Development of Toxicity Benchmarks for Nitrogen-based Energetic Materials for the Enchytraeid Worm, Enchytraeus crypticus

DTIC Science & Technology

2013-11-01

pp 177–182. Anzhi, Z.L.; Marx, K.A.; Walker, J.; Kaplan, D.L. Trinitrotoluene and Metabolites Binding to Humic Acid . Environ. Sci. Technol. 1997...2001, pp 293–312. Thorn, K.A.; Kennedy, K.R. 15 N NMR Investigation of the Covalent Binding of Reduced TNT Amines to Soil Humic Acid , Model...9 3.2 Toxicity of Reference Toxicant, Boric Acid , to the Potworm E. crypticus ......15 3.3 Effects of 2,4-DNT on the Potworm E. crypticus

An angle encoder for super-high resolution and super-high accuracy using SelfA

NASA Astrophysics Data System (ADS)

Watanabe, Tsukasa; Kon, Masahito; Nabeshima, Nobuo; Taniguchi, Kayoko

2014-06-01

Angular measurement technology at high resolution for applications such as in hard disk drive manufacturing machines, precision measurement equipment and aspherical process machines requires a rotary encoder with high accuracy, high resolution and high response speed. However, a rotary encoder has angular deviation factors during operation due to scale error or installation error. It has been assumed to be impossible to achieve accuracy below 0.1″ in angular measurement or control after the installation onto the rotating axis. Self-calibration (Lu and Trumper 2007 CIRP Ann. 56 499; Kim et al 2011 Proc. MacroScale; Probst 2008 Meas. Sci. Technol. 19 015101; Probst et al Meas. Sci. Technol. 9 1059; Tadashi and Makoto 1993 J. Robot. Mechatronics 5 448; Ralf et al 2006 Meas. Sci. Technol. 17 2811) and cross-calibration (Probst et al 1998 Meas. Sci. Technol. 9 1059; Just et al 2009 Precis. Eng. 33 530; Burnashev 2013 Quantum Electron. 43 130) technologies for a rotary encoder have been actively discussed on the basis of the principle of circular closure. This discussion prompted the development of rotary tables which achieve reliable and high accuracy angular verification. We apply these technologies for the development of a rotary encoder not only to meet the requirement of super-high accuracy but also to meet that of super-high resolution. This paper presents the development of an encoder with 221 = 2097 152 resolutions per rotation (360°), that is, corresponding to a 0.62″ signal period, achieved by the combination of a laser rotary encoder supplied by Magnescale Co., Ltd and a self-calibratable encoder (SelfA) supplied by The National Institute of Advanced Industrial Science & Technology (AIST). In addition, this paper introduces the development of a rotary encoder to guarantee ±0.03″ accuracy at any point of the interpolated signal, with respect to the encoder at the minimum resolution of 233, that is, corresponding to a 0.0015″ signal period after interpolation of 212 (= 4096) divisions through the interpolator.

Microfluidic Experiments Studying Pore Scale Interactions of Microbes and Geochemistry

NASA Astrophysics Data System (ADS)

Chen, M.; Kocar, B. D.

2016-12-01

Understanding how physical phenomena, chemical reactions, and microbial behavior interact at the pore-scale is crucial to understanding larger scale trends in groundwater chemistry. Recent studies illustrate the utility of microfluidic devices for illuminating pore-scale physical-biogeochemical processes and their control(s) on the cycling of iron, uranium, and other important elements 1-3. These experimental systems are ideal for examining geochemical reactions mediated by microbes, which include processes governed by complex biological phenomenon (e.g. biofilm formation, etc.)4. We present results of microfluidic experiments using a model metal reducing bacteria and varying pore geometries, exploring the limitations of the microorganisms' ability to access tight pore spaces, and examining coupled biogeochemical-physical controls on the cycling of redox sensitive metals. Experimental results will provide an enhanced understanding of coupled physical-biogeochemical processes transpiring at the pore-scale, and will constrain and compliment continuum models used to predict and describe the subsurface cycling of redox-sensitive elements5. 1. Vrionis, H. A. et al. Microbiological and geochemical heterogeneity in an in situ uranium bioremediation field site. Appl. Environ. Microbiol. 71, 6308-6318 (2005). 2. Pearce, C. I. et al. Pore-scale characterization of biogeochemical controls on iron and uranium speciation under flow conditions. Environ. Sci. Technol. 46, 7992-8000 (2012). 3. Zhang, C., Liu, C. & Shi, Z. Micromodel investigation of transport effect on the kinetics of reductive dissolution of hematite. Environ. Sci. Technol. 47, 4131-4139 (2013). 4. Ginn, T. R. et al. Processes in microbial transport in the natural subsurface. Adv. Water Resour. 25, 1017-1042 (2002). 5. Scheibe, T. D. et al. Coupling a genome-scale metabolic model with a reactive transport model to describe in situ uranium bioremediation. Microb. Biotechnol. 2, 274-286 (2009).

Origin of Ultralow Friction and Wear in Ultrananocrystalline Diamond

DTIC Science & Technology

2008-06-11

Erdemir, G. R. Fenske , A. R. Krauss, D. M. Gruen, T. McCauley, and R. T. Csencsits, Surf. Coat. Technol. 120–121, 565 (1999). [3] S. E. Grillo and J...and A. Erdemir, Tribol. Lett. 21, 51 (2006). [6] A. Erdemir, O. L. Eryilmaz, and G. Fenske , J. Vac. Sci. Technol. A 18, 1987 (2000). [7] L. Sun, Q. Wu... Fenske , C. Zuiker, R. Csencsits, A. R. Krauss, and D. M. Gruen, Tribol. Trans. 40, 667 (1997). [28] Worn and unworn areas were imaged in the same

Recent Experimental Advances to Determine (noble) Gases in Waters

NASA Astrophysics Data System (ADS)

Kipfer, R.; Brennwald, M. S.; Huxol, S.; Mächler, L.; Maden, C.; Vogel, N.; Tomonaga, Y.

2013-12-01

In aquatic systems noble gases, radon, and bio-geochemically conservative transient trace gases (SF6, CFCs) are frequently applied to determine water residence times and to reconstruct past environmental and climatic conditions. Recent experimental breakthroughs now enable ● to apply the well-established concepts of terrestrial noble gas geochemistry in waters to the minute water amounts stored in sediment pore space and in fluid inclusions (A), ● to determine gas exchange processes on the bio-geochemical relevant time scales of minutes - hours (B), and ● to separate diffusive and advective gas transport in soil air (C). A. Noble-gas analysis in water samples (< 1 g) facilitates determining the solute transport in the pore space and identifying the origin of bio- and geogenic fluids in (un) consolidated sediments [1]. Advanced techniques that combine crushing and sieving speleothem samples in ultra-high-vacuum to a specific grain size allow to separate air and water-bearing fluid inclusions and thus enables noble-gas-based reconstruction of environmental conditions from water masses as small as 1mg [2]. B. The coupling of noble gas analysis with approaches of gas chromatography permits combined analysis of noble gases and other gases species (e.g., SF6, CFCs, O2, N2) from a single water sample. The new method substantially improves ground water dating by SF6 and CFCs as excess air is quantified from the same sample and hence can adequately be corrected for [3]. Portable membrane-inlet mass spectrometers enable the quasi-continuous and real-time analysis of noble gases and other dissolved gases directly in the field, allowing, for instance, quantification of O2 turnover rates on small time scales [4]. C. New technical developments perfect 222Rn analysis in water by the synchronous the determination of the short-lived 220Rn. The combined 220,222Rn analysis sheds light on the emanation behaviour of radon by identifying soil water content to be the crucial control of 220Rn occurrence in the environment, e.g., making an argument why 220Rn is not detectable in water, but in soil air. As 220Rn occurrence is of 'very local origin' the combined analysis of 220,222Rn in soil air allows differentiating between advective and diffusive soil gas transport [5]. By discussing these recent achievements, we intend to stimulate a broader discussion to identify future applications of noble and other gases in (un) conventional aquatic systems, such as blood. [1] Tomonaga et al. (2011) Limnol. Oceanogr. Methods, 9, 42-49, doi:10:4319/lom.2011.9.42. [2] Vogel et al. (2013) Geochem. Geophys. Geosyst., 14, doi:10.1002/ggge.20164. [3] Brennwald et al. (2013) Environ. Sci. Technol., Article ASAP, DOI: 10.1021/es401698p. [4] Mächler et al. (2012) Environ. Sci. Technol., 47, 7060-7066. [5] Huxol et al. Environ. Sci. Technol., in revision.

Helio Moutinho | NREL

Science.gov Websites

length in single grains and the effect of grain boundaries in CdTe, and the effects of defects on the diffraction of CdTe thin films: Effects of CdCl2 treatment, J. Vac. Sci. Technol. A 26, 1068 (2008). H.R

Virtual Impactor for Sub-micron Aerosol Particles

NASA Astrophysics Data System (ADS)

Bolshakov, A. A.; Strawa, A. W.; Hallar, A. G.

2005-12-01

The objective of a virtual impactor is to separate out the larger particles in a flow from the smaller particles in such a way that both sizes of particles are available for sampling. A jet of particle-laden air is accelerated toward a collection probe so that a small gap exists between the acceleration nozzle and the probe. A vacuum is applied to deflect a major portion of the airstream away form the collection probe. Particles larger than a certain size have sufficient momentum so that they cross the deflected streamlines and enter the collection probe, whereas smaller particles follow the deflected streamlines. The result is that the collection probe will contain a higher concentration of larger particles than is in the initial airstream. Typically, virtual impactors are high-flow devices used to separate out particles greater than several microns in diameter. We have developed a special virtual impactor to concentrate aerosol particles of diameters between 0.5 to 1 micron for the purpose of calibrating the optical cavity ring-down instrument [1]. No similar virtual impactors are commercially available. In our design, we have exploited considerations described earlier [2-4]. Performance of our virtual impactor was evaluated in an experimental set-up using TSI 3076 nebulizer and TSI 3936 scanning mobility particle size spectrometer. Under experimental conditions optimized for the best performance of the virtual impactor, we were able to concentrate the 700-nm polystyrene particles no less than 15-fold. However, under experimental conditions optimized for calibrating our cavity ring-down instrument, a concentration factor attainable was from 4 to 5. During calibration experiments, maximum realized particle number densities were 190, 300 and 1600 cm-3 for the 900-nm, 700-nm and 500-nm spheres, respectively. This paper discusses the design of the impactor and laboratory studies verifying its performance. References: 1. A.W. Strawa, R. Castaneda, T. Owano, D.S. Baer, B.A. Paldus, J. Atm. Ocean. Technol., 20, 454-465 (2003). 2. V.A. Marple, K.L. Rubow, B.A. Olson, Aerosol Sci. Technol., 22, 140-150 (1995). 3. B.T. Chen, H.C. Yeh, Y.S. Cheng, J. Aerosol Sci., 16, 343-354 (1985). 4. V.A. Marple, C.M. Chien, Environ. Sci. Technol., 14, 976-985 (1980).

Defense and Arms Control Studies Program

DTIC Science & Technology

1991-01-01

States Military Academy, Poli. Sci. Massachusetts Institute of Technol- ogy, Electr. Eng. Craig Wheeler Cynthia Womack University of California-San...of the Assistant Secretary of Defense (Program Analysis and Evaluation), "Total Force Policy" November 6 - M. Gen. Gene A. Deegan , USMC Vice Director

Particle Deposition onto Enclosure Surfaces

DTIC Science & Technology

2009-08-20

Deposition on Semiconductor Wafers," Aerosol Sci. Technol. 6, 215 (1987). 3. S. E. Pratsinis, T. T. Kodas , M. P. Dudukovic, and S. K. Friedlander...29, 511 (1998). 11. T. T. Kodas , "Generation of Complex Metal Oxides by Aerosol Processes: Superconducting Ceramic Particles and Films," Adv. Mater

High Energy Density Dielectrics for Pulsed Power Applications

DTIC Science & Technology

2008-09-01

Energy/Power/Thermal Division //Signature// DEREK M. LINCOLN, Major, USAF Deputy Chief Energy/Power/Thermal Division Propulsion Directorate...comparative study," J. Vac. Sci. Technol. A 16, (1998), 2804-2815. 11 T.T. Leung and C.W. Ong . “Nearly amorphous to epitxial growth of aluminum nitride

Helicon antenna radiation patterns in a high-density hydrogen linear plasma device

NASA Astrophysics Data System (ADS)

Caneses, J. F.; Blackwell, B. D.; Piotrowicz, P.

2017-11-01

Antenna radiation patterns in the vicinity of a helicon antenna are investigated in hydrogen plasmas produced in the MAGPIE linear plasma device. Using a uniform cold-plasma full-wave code, we model the wave physics in MAGPIE and find good agreement with experimental wave measurements. We show for the first time which antenna elements in a helicon device couple most strongly to the plasma and discuss the physical mechanism that determines this effect. Helicon wavefields in the near field of the antenna are best described in terms of the group velocity and ray direction, while far from the antenna, helicon wavefields behave like plane waves and are best described in terms of eigen-modes. In addition, we present recent 2D axis-symmetric full-wave simulations of the 120 kW helicon source in ProtoMPEX [Rapp et al., IEEE Trans. Plasma Sci. 44(12), 3456-3464 (2016); Caughman et al., J. Vac. Sci. Technol. Vac. Surf. Films 35, 03E114 (2017); and Goulding et al., Fusion Sci. Technol. 72(4), 588-594 (2017)] ( n e ˜ 5 × 1019 m-3, B 0 ˜ 70 mT, and f = 13.56 MHz) where the antenna radiation patterns are evident, and we provide an interpretation of the numerical results using the ideas developed in this paper.

Richard Ahrenkiel | NREL

Science.gov Websites

Kuciauskas, J Tynan, "Dual-sensor technique for characterization of carrier lifetime decay transients in semiconductors", Journal of Applied Physics 116 (21), 214510 (2014) J. Moseley, M.M. Al-Jassim, H.R For Contactless Measurement of Carrier Lifetime", J. Vac. Sci. Technol. B 31, 04D113 R. K

Post-CMOS Micromachining of Surface and Bulk Structures

DTIC Science & Technology

2002-05-06

Structures iii Acknowledgements I would like to thank my advisors, Professor Gary K. Fedder and Professor Dave W. Greve, for their continuing support...Donnelly, Plasma Chem. Plasma Process, vol. 1, pp. 37, 1981. [54] J. L. Mauer, J. S. Logan, L. B. Zielinski , and G. S. Schwartz, J. Vac. Sci. Technol

Understanding helicon plasmas

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tarey, R. D.; Sahu, B. B.; Ganguli, A.

2012-07-15

This paper presents a comprehensive overview of work on the helicon plasmas and also discusses various aspects of RF power deposition in such plasmas. Some of the work presented here is a review of earlier work on theoretical [A. Ganguli et al., Phys. Plasmas 14, 113503 (2007)] and experimental [A. Ganguli et al., Plasma Sources Sci. Technol. 20(1), 015021 (2011)] investigations on helicon plasmas in a conducting cylindrical waveguide for m = -1 mode. This work also presents an approach to investigate the mechanisms by which the helicon and associated Trivelpiece-Gould (TG) waves are responsible for RF power deposition inmore » Helicon discharges. Experiment design adopts the recent theory of damping and absorption of Helicon modes in conducting waveguides [A. Ganguli et al., Phys. Plasmas 14, 113503 (2007)]. The effort has also been made to detect the warm electrons, which are necessary for ionization, because Helicon discharges are of high density, low T{sub e} discharges and the tail of the bulk electron population may not have sufficient high-energy electrons. Experimental set up also comprises of the mirror magnetic field. Measurements using RF compensated Langmuir probes [A. Ganguli et al., Plasma Sources Sci. Technol. 17, 015003 (2008)], B-dot probe and computations based on the theory shows that the warm electrons at low pressure (0.2-0.3 mTorr) Helicon discharges, are because of the Landau damping of TG waves. In collisional environment, at a pressure Almost-Equal-To 10 mTorr, these high-energy electrons are due to the acceleration of bulk electrons from the neighboring regions across steep potential gradients possibly by the formation of double layers.« less

Process diagnostics and monitoring using the multipole resonance probe in an inhomogeneous plasma for ion-assisted deposition of optical coatings

NASA Astrophysics Data System (ADS)

Styrnoll, T.; Harhausen, J.; Lapke, M.; Storch, R.; Brinkmann, R. P.; Foest, R.; Ohl, A.; Awakowicz, P.

2013-08-01

The application of a multipole resonance probe (MRP) for diagnostic and monitoring purposes in a plasma ion-assisted deposition (PIAD) process is reported. Recently, the MRP was proposed as an economical and industry compatible plasma diagnostic device (Lapke et al 2011 Plasma Sources Sci. Technol. 20 042001). The major advantages of the MRP are its robustness against dielectric coating and its high sensitivity to measure the electron density. The PIAD process investigated is driven by the advanced plasma source (APS), which generates an ion beam in the deposition chamber for the production of high performance optical coatings. With a background neutral pressure of p0 ˜ 20 mPa the plasma expands from the source region into the recipient, leading to an inhomogeneous spatial distribution. Electron density and electron temperature vary over the distance from substrate (ne ˜ 109 cm-3 and Te,eff ˜ 2 eV) to the APS (ne ≳ 1012 cm-3 and Te,eff ˜ 20 eV) (Harhausen et al 2012 Plasma Sources Sci. Technol. 21 035012). This huge variation of the plasma parameters represents a big challenge for plasma diagnostics to operate precisely for all plasma conditions. The results obtained by the MRP are compared to those from a Langmuir probe chosen as reference diagnostics. It is demonstrated that the MRP is suited for the characterization of the PIAD plasma as well as for electron density monitoring. The latter aspect offers the possibility to develop new control schemes for complex industrial plasma environments.

Optoelectronic Integration

DTIC Science & Technology

1992-03-20

34 Interband Transitions in InGaAs/GaAs Strained Layer Superlattices ," J. of Vac. Sci and Technol. B, Vol. 7(5), pp. 1106-1110, 1989. 33 B. Kh...2 II. C. Resonant Cavity-Enhanced Photodetectors ................................ .............. 3 II. D. Wavelength Selective Optoelectronic...Simultions of Electronic States in Semiconductor Quantum Wells and Superlattices under Electrical Field ................................ ....... 5 II. G . G

Contact Formation (Hg, CD)Te

DTIC Science & Technology

1989-12-01

Davis, W.A. Beck, D.G. Kilday, J.T. McKinley, and G. Margaritondo, J. Vac. Sci. Technol. A 7, 870 (1989). 312 J.M. Pawlikowski, Acta Physica Polonica A49...139 (1976). J.M. Pawlikowski, Acta Physica Polonica A49, 563 (1976). J.M. Pawlikowski, Acta Physica Polonica A51, 95 (1977). SJ.M. Pawlikowski, Phys

Navigating Tensions between Conceptual and Metaconceptual Goals in the Use of Models

ERIC Educational Resources Information Center

Delgado, Cesar

2015-01-01

Science education involves learning about phenomena at three levels: concrete (facts and generalizations), conceptual (concepts and theories), and metaconceptual (epistemology) (Snir et al. in "J Sci Educ Technol" 2(2):373-388, 1993). Models are key components in science, can help build conceptual understanding, and may also build…

Reduced PM2.5 Emissions for Military Gas Turbine Engines using Fuel Additives

DTIC Science & Technology

2006-08-12

indicator of the presence of PAH species in hydrocarbon flames [ Naegeli 1998, Bomse 1992]. Although fluorescence originates from a wide range of aromatic...Env. Sci. Technol., 32:2033, 1998. Mueller, M. , R Yetter, F. Dryer, ChemKinet 31 (1999) 705-724. Naegeli , D.W. and K.H. Childress, "Lower

Chaiwat Engtrakul | NREL

Science.gov Websites

, College Park B.S. Chemistry, Gettysburg College Featured Publications M.Z. Hu, C. Engtrakul, B.L. Bischoff Applications." Separ. Sci. Technol., 53, 528-543. C. Engtrakul, M.Z. Hu, B.L. Bischoff, G.G. Jang (2016 Catalytic Fast Pyrolysis of Pine Biomass." Energy Fuels, 30, 8343-8348. C. Engtrakul, C. Mukarakate

Application of common y-intercept regression parameters for log Kp vs 1/ T for predicting gas-particle partitioning in the urban environment

NASA Astrophysics Data System (ADS)

Pankow, James F.

Gas-particle partitioning is examined using a partitioning constant Kp = ( F/ TSP)/ A, where F (ng m -3) and A (ng m -3) are the particulate-associated and gas-phase concentrations, respectively, and TSP is the total suspended particulate matter level (μg m -3). Compound-dependent values of Kp depend on temperature ( T) according to Kp = mp/ T + bp. Limitations in data quality can cause errors in estimates of mp and bp obtained by simple linear regression (SLR). However, within a group of similar compounds, the bp values will be similar. By pooling data, an improved set of mp and a single bp can be obtained by common y-intercept regression (CYIR). SLR estimates for mp and bp for polycyclic aromatic hydrocarbons (PAHs) sorbing to urban Osaka particulate matter are available (Yamasaki et al., 1982, Envir. Sci. Technol.16, 189-194), as are CYIR estimates for the same particulate matter (Pankow, 1991, Atmospheric Environment25A, 2229-2239). In this work, a comparison was conducted of the ability of these two sets of mp and bp to predict A/ F ratios for PAHs based on measured T and TSP values for data obtained in other urban locations, specifically: (1) in and near the Baltimore Harbor Tunnel by Benner (1988, Ph.D thesis, University of Maryland) and Benner et al. (1989, Envir. Sci. Technol.23, 1269-1278); and (2) in Chicago by Cotham (1990, Ph.D. thesis, University of South Carolina). In general, the CYIR estimates for mp and bp obtained for Osaka particulate matter were found to be at least as reliable, and for some compounds more reliable than their SLR counterparts in predicting gas-particle ratios for PAHs. This result provides further evidence of the utility of the CYIR approach in quantitating the dependence of log Kp values on 1/ T.

Ligand-controlled Fe mobilization catalyzed by adsorbed Fe(II) on Fe(hydr)oxides

NASA Astrophysics Data System (ADS)

Kang, Kyounglim; Biswakarma, Jagannath; Borowski, Susan C.; Hug, Stephan J.; Hering, Janet G.; Schenkeveld, Walter D. C.; Kraemer, Stephan M.

2017-04-01

Dissolution of Fe(hydr)oxides is a key process in biological iron acquisition. Due to the low solubility of iron oxides in environments with a circumneutral pH, organisms may exude organic compounds catalyzing iron mobilization by reductive and ligand controlled dissolution mechanisms. Recently, we have shown synergistic effects between reductive dissolution and ligand-controlled dissolution that may operate in biological iron acquisition. The synergistic effects were observed in Fe mobilization from single goethite suspensions as well as in suspensions containing calcareous soil[1],[2]. However, how the redox reaction accelerates Fe(hydr)oxide dissolution by ligands is not studied intensively. In our study, we hypothesized that electron transfer to structural Fe(III) labilizes the Fe(hydr)oxide structure, and that this can accelerate ligand controlled dissolution. Systematical batch dissolution experiments were carried out under anoxic conditions at environmentally relevant pH values in which various Fe(hydr)oxides (goethite, hematite, lepidocrocite) interacted with two different types of ligand (desferrioxamine B (DFOB) and N,N'-Di(2-hydroxybenzyl)ethylenediamine-N,N'-diacetic acid monohydrochloride (HBED)). Electron transfer to the structure was induced by adsorbing Fe(II) to the mineral surface at various Fe(II) concentrations. Our results show a distinct catalytic effect of adsorbed Fe(II) on ligand controlled dissolution, even at submicromolar Fe(II) concentrations. We observed the effect for a range of iron oxides, but it was strongest in lepidocrocite, most likely due to anisotropy in conductivity leading to higher near-surface concentration of reduced iron. Our results demonstrate that the catalytic effect of reductive processes on ligand controlled dissolution require a very low degree of reduction making this an efficient process for biological iron acquisition and a potentially important effect in natural iron cycling. References 1. Wang, Z. M.; Schenkeveld, W. D. C.; Kraemer, S. M.; Giammar, D. E. Environ. Sci. Technol. 2015, 49, (12), 7236-7244. 2. Schenkeveld, W. D. C.; Wang, Z. M.; Giammar, D. E.; Kraemer, S. M. Environ. Sci. Technol. 2016, 50, (12), 6381-6388.

PREFACE: Superconductivity in ultrathin films and nanoscale systems Superconductivity in ultrathin films and nanoscale systems

NASA Astrophysics Data System (ADS)

Bianconi, Antonio; Bose, Sangita; Garcia-Garcia, Antonio Miguel

2012-12-01

The recent technological developments in the synthesis and characterization of high-quality nanostructures and developments in the theoretical techniques needed to model these materials, have motivated this focus section of Superconductor Science and Technology. Another motivation is the compelling evidence that all new superconducting materials, such as iron pnictides and chalcogenides, diborides (doped MgB2) and fullerides (alkali-doped C60 compounds), are heterostrucures at the atomic limit, such as the cuprates made of stacks of nanoscale superconducting layers intercalated by different atomic layers with nanoscale periodicity. Recently a great amount of interest has been shown in the role of lattice nano-architecture in controlling the fine details of Fermi surface topology. The experimental and theoretical study of superconductivity in the nanoscale started in the early 1960s, shortly after the discovery of the BCS theory. Thereafter there has been rapid progress both in experiments and the theoretical understanding of nanoscale superconductors. Experimentally, thin films, granular films, nanowires, nanotubes and single nanoparticles have all been explored. New quantum effects appear in the nanoscale related to multi-component condensates. Advances in the understanding of shape resonances or Fano resonances close to 2.5 Lifshitz transitions near a band edge in nanowires, 2D films and superlattices [1, 2] of these nanosized modules, provide the possibility of manipulating new quantum electronic states. Parity effects and shell effects in single, isolated nanoparticles have been reported by several groups. Theoretically, newer techniques based on solving Richardson's equation (an exact theory incorporating finite size effects to the BCS theory) numerically by path integral methods or solving the entire Bogoliubov-de Gennes equation in these limits have been attempted, which has improved our understanding of the mechanism of superconductivity in these confined systems. In addition, the role of thermodynamic fluctuations on superconducting properties has been extensively studied in the context of nanoparticles and nanowires both experimentally and theoretically. In the past decade, a lot of work has been initiated in the area of interface superconductivity where different techniques have been demonstrated to tune Tc. Although the progress in this field has deepened our understanding of nanoscale superconductors, there are several open and key questions which need to be addressed. Some of these are: (1) can superconductivity be enhanced and Tc increased in nanostructures with respect to the bulk limit and if so, how can it be controlled? (2) What are the theoretical and experimental limits for the enhancement and control of superconductivity? (3) Can the phenomena identified in conventional nanostructures shed light on phenomena in high Tc superconductors and vice versa? (4) How will the new fundamental physics of superconductivity at the nanoscale promote advances in nanotechnology applications and vice versa? The papers in this focus section reflect the advances made in this field, in particular in nanowires and nanofilms, but also attempt to answer some of the key open questions outlined above. The theoretical papers explore unconventional quantum phenomena such as the role of confinement in the dynamics of single Cooper pairs in isolated grains [1] and Fano resonances in superconducting gaps in multi-condensate superconductors near a 2.5 Lifshitz transition [2]. Here a new emerging class of quantum phenomena of fundamental physics appear at the Bose-BCS crossover in multi-condensate superconductors [2]. Nanosize effects can now be manipulated by controlling defects in layered oxides [3]. A new approach is provided by controlling the self-organization of oxygen interstitials in layered copper oxides that show an intrinsic nanoscale phase separation [4]. In this case a non-trivial distribution of superconducting nanograins appears to enhance the critical temperature [4]. This is a hot topic as in the past year many works have clarified the nanoscale phase separation in electron-doped chalcogenides, showing the key role of a complex texture of nanograins and opening new avenues for the fundamental understanding of quantum phenomena in networks of superconducting nanograins. The advances in nanotechnology allow the exploration of the possible existence of superconductivity in single carbon nanotubes [5]. The technological applications presented by Gomez [6] and Lehtinen [7] show the fundamental physics of superconductivity at the nanoscale to promote new advances in quantum devices. We hope that this combination will make these focus papers in Superconductor Science and Technology interesting and promote cross-fertilization among the different sub-branches of the field which all share the same goal of addressing the key questions on nanoscale superconductors. References [1]Croitoru M D, Vagov A, Shanenko A A and Axt V M 2012 The Cooper problem in nanoscale: enhancement of the coupling due to confinement Supercond. Sci. Technol. 25 124001 [2]Perali A, Innocenti A, Valletta A and Bianconi A 2012 Anomalous isotope effect near a 2.5 Lifshitz transition in a multi-band multi-condensate superconductor made of a superlattice of stripes Supercond. Sci. Technol. 25 124002 [3]Zeng S W, Huang Z, Wang X, Lü W M, Liu Z Q, Zhang B M, Dhar S, Venkatesan T and Ariando 2012 The influence of La substitution and oxygen reduction in ambipolar La-doped YBa2Cu3Oy thin films Supercond. Sci. Technol. 25 124003 [4]Poccia N, Bianconi A, Campi G, Fratini M and Ricci A 2012 Size evolution of the oxygen interstitial nanowires in La2CuO4+y by thermal treatments and x-ray continuous illumination Supercond. Sci. Technol. 25 124004 [5]Yang Y, Fedorov G, Zhang J, Tselev A, Shafranjuk S and Barbara P 2012 The search for superconductivity at van Hove singularities in carbon nanotubes Supercond. Sci. Technol. 25 124005 [6]Gomez A, Gonzalez E M and Vicent J L 2012 Superconducting vortex dynamics on arrays with bicrystal-like structures: matching and rectifier effects Supercond. Sci. Technol. 25 124006 [7]Lehtinen J S and Arutyunov K Yu 2012 The quantum phase slip phenomenon in superconducting nanowires with a low-Ohmic environment Supercond. Sci. Technol. 25 124007

Particle processing technology

NASA Astrophysics Data System (ADS)

Sakka, Yoshio

2014-02-01

In recent years, there has been strong demand for the development of novel devices and equipment that support advanced industries including IT/semiconductors, the environment, energy and aerospace along with the achievement of higher efficiency and reduced environmental impact. Many studies have been conducted on the fabrication of innovative inorganic materials with novel individual properties and/or multifunctional properties including electrical, dielectric, thermal, optical, chemical and mechanical properties through the development of particle processing. The fundamental technologies that are key to realizing such materials are (i) the synthesis of nanoparticles with uniform composition and controlled crystallite size, (ii) the arrangement/assembly and controlled dispersion of nanoparticles with controlled particle size, (iii) the precise structural control at all levels from micrometer to nanometer order and (iv) the nanostructural design based on theoretical/experimental studies of the correlation between the local structure and the functions of interest. In particular, it is now understood that the application of an external stimulus, such as magnetic energy, electrical energy and/or stress, to a reaction field is effective in realizing advanced particle processing [1-3]. This special issue comprises 12 papers including three review papers. Among them, seven papers are concerned with phosphor particles, such as silicon, metals, Si3N4-related nitrides, rare-earth oxides, garnet oxides, rare-earth sulfur oxides and rare-earth hydroxides. In these papers, the effects of particle size, morphology, dispersion, surface states, dopant concentration and other factors on the optical properties of phosphor particles and their applications are discussed. These nanoparticles are classified as zero-dimensional materials. Carbon nanotubes (CNT) and graphene are well-known one-dimensional (1D) and two-dimensional (2D) materials, respectively. This special issue also includes two papers on the fabrication of mechanically reliable nanocomposites by dispersing graphene into a ceramic matrix, and on supercapacitors with high energy densities in a Co(OH)2 system decorated with graphene and carbon nanotubes. As a novel preparation method of oxide films, the fabrication of alumina films with laminated structures by ac anodization is reviewed. Moreover a new type of nanosheet has been fabricated by the exfoliation of layered, ternary transition-metal carbide and nitride compounds, known as Mn + 1AXn phases (or MAX phases) where M is an early transition metal, such as Ti or Nb, A is an A group element, such as Si or Al, X is carbon and/or nitrogen and n = 1-3 [4]. Among the MAX phases, those containing Mo have been theoretically calculated by first-principles calculations to be a source for obtaining Mo2C nanosheets with potentially unique properties. As an example of improving bulk ceramic properties, texturing by using a high magnetic field [5] and sintering by the electric current activated/assisted sintering (ECAS) technology [6] have been demonstrated for ultra-high temperature ceramics with high-temperature strength. A project on the development of materials and particle processing for the field of environment and energy has been ongoing at the National Institute for Materials Science since April 2011. This project employs various core competence technologies for particle processing such as ion beam irradiation for nanoparticle fabrication [7], fullerene nanomaterial processing using liquid-liquid interface precipitation [8], a gas reduction nitridation process to obtain Si3N4-based phosphor materials [9], advanced phosphors via novel processing [10, 11], ultra-high pressure technology for processing and in situ analysis [12, 13], colloidal processing in a high magnetic field to obtain laminated, textured ceramics [1, 3, 5], the ECAS process for nanostructuring ceramics [6] and so forth. Here, I would like to introduce some research achievements that are not covered in this special issue. (1) The evolution of hydrogen by the reaction of fine metal particles such as Al [14] and Mg [15] with water; the specific surface area and surface modification are important factors.(2) The realization of new carbon related materials with 1D and 2D structures consisting of fullerenes prepared by liquid-liquid interface precipitation: alkaline-doped superconductive nanotubes consisting of fullerenes [16], application to solar cells of fullerene/cobalt porphyrin hybrid nanosheets [17], etc.(3) The fabrication of textured films and bulk materials with excellent functional properties by colloidal processing methods such as slip casting [5], gel casting [18] and electrophoretic deposition [3, 19], in a high magnetic field, and with subsequent heating; examples of such materials include dye-sensitized TiO2 solar cells, thermoelectric materials and cathode materials for solid state Li-ion batteries and dielectric ceramics.(4) The fabrication of high-strength and high-toughness MAX phase ceramics [20, 21] inspired by the nacreous structure [22].(5) The modeling and development of the ECAS process [6]. This involves two-step pressure application [23] and high-pressure application above 400 MPa to fabricate transparent oxides [24-26], and rapid heating to obtain dense nanocomposites of ceramic-CNT [27] and diamonds [28].(6) The contraction of ternary phase diagrams for oxide ion conductor systems such as zirconia [29] and apatite systems [30], leading to an increased understanding of the stability of such systems and assisting the search for high oxygen ion conductors. Acknowledgments I am grateful to the authors who have contributed to this special issue, and sincerely hope that the readers will expand their knowledge of particle processing technology. References [1] Sakka Y 2006 J. Ceram. Soc. Japan 114 371 [2] Badica P, Crisan A, Aldica G, Endo K, Borodianska H, Togano K, Awaji S, Vasylkiv O and Sakka Y 2011 Sci. Technol. Adv. Mater. 12 013001 [3] Sakka Y and Uchikoshi T 2010 KONA Powder Particle J. 28 74 (kona.or.jp/search/28_074.pdf) [4] Naguib M, Mashtalir O, Carle J, Presser V, Lu J, Hultman L, Gogotsi Y and Barsoum M W 2012 ACS Nano 6 1322 [5] Sakka Y and Suzuki T S 2005 J. Ceram. Soc. Japan 113 26 [6] Grasso S, Sakka Y and Maizza G 2009 Sci. Technol. Adv. Mater. 10 053001 [7] Nakao H, Tokonami S, Hamada T, Shiigi H, Nagaoka T, Iwate F and Takeda Y 2012 Nanoscale 4 6814 [8] Miyazawa K and Hotta K 2010 J. Cryst. Growth 312 2764 [9] Suehiro T, Xie R and Hirosaki N 2013 Indust. Eng. Chem. Res. 52 7453 [10] Zhu Q, Li J-G, Li X, Sun X and Sakka Y 2011 Sci. Technol. Adv. Mater. 12 055001 [11] Li J, Li J-G, Zhang Z, Wu X, Liu S, Li X, Sun X and Sakka Y 2012 Sci. Technol. Adv. Mater. 13 035007 [12] Kawamura F, Yusa H and Taniguchi T 2012 Appl. Phys. Lett. 100 251910 [13] Watanabe K and Taniguchi T 2011 Int. J. Appl. Ceram. Technol. 8 977 [14] Deng Z-Y, Ferreira J M F and Sakka Y 2008 J. Am. Ceram. Soc. 91 3825 [15] Uda M, Okuyama H, Suzuki T S and Sakka Y 2012 Sci. Technol. Adv. Mater. 13 025009 [16] Takeya H, Kato R, Wakahara T, Miyazawa K, Yamaguchi T, Ozaki T, Okazaki H and Takano Y 2013 Mater. Res. Bull. 48 343 [17] Wakahara T, D'Angelo P, Miyazawa K, Nemoto Y, Ito O, Tanigaki N, Bradley D D C and Anthopoulos T D 2012 J. Am. Chem. Soc. 134 7204 [18] Wiecinska P, Sakka Y, Suzuki T S, Uchikoshi T, Mizerski T and Szafran M 2013 J. Ceram. Soc. Japan 121 89 [19] Kawakita M, Uchikoshi T, Kawakita J and Sakka Y 2009 J. Am. Ceram. Soc. 92 984 [20] Hu C, Sakka Y, Grasso S, Nishimura T, Guo S and Tanaka H 2011 Scr. Mater. 64 765 [21] Hu C, Sakka Y, Nishimura T, Guo S, Grasso S and Tanaka H 2011 Sci. Technol. Adv. Mater. 12 044603 [22] Kakisawa H and Sumitomo T 2011 Sci. Technol. Adv. Mater. 12 064710 [23] Grasso S, Hu C F, Maizza G, Kim B N and Sakka Y 2011 J. Am. Ceram. Soc. 94 1405 [24] Grasso S, Kim B N, Hu C F, Maizza G and Sakka Y 2010 J. Am. Ceram. Soc. 93 2460 [25] Zhang H B, Kim B N, Morita K, Hiraga K, Yoshida H and Sakka Y 2012 Sci. Technol. Adv. Mater. 13 055003 [26] Kim B-N, Hiraga K, Grasso S, Morita K, Yoshida H, Zhang H and Sakka Y 2012 J. Ceram. Soc. Japan 120 116 [27] Estili M, Kawasaki A and Sakka Y 2012 Adv. Mater. 24 4322 [28] Grasso S, Hu C F, Maizza G and Sakka Y 2012 J. Am. Ceram. Soc. 95 2423 [29] Andrievskaya E R, Kornienko O A, Sayir A, Vasylkiv O and Sakka Y 2011 J. Am. Ceram. Soc. 94 1911 [30] Kobayashi K and Sakka Y 2012 Sci. Technol. Adv. Mater. 13 045006

Strained InGaAs/InAlAs Quantum Wells for Complementary III-V Transistors

DTIC Science & Technology

2014-01-01

GaAs substrates for low power and high frequency applications, J. Appl. Phys. 109 (2011) 033706. [28] A. Ali, H. Madan , A. Agrawal, I. Ramirez, R...Growth of InAsSb-channel high electron mobility transistor structures, J. Vac. Sci. Technol. B 23 (2005) 1441–1444. [30] A. Ali, H. Madan , M.J

Finite Element Modeling of Viscoelastic Behavior and Interface Damage in Adhesively Bonded Joints

DTIC Science & Technology

2012-01-01

eccentricity of the axis of a lap joint gives rise to transverse or peel stresses at the Report Documentation Page Form ApprovedOMB No. 0704-0188...Computers and Structures 29, 1011 (1988). 21 S. Roy and J. N. Reddy, Tire Sci. Technol. 16, 146 (1988). 22 S. Roy and J. N. Reddy, Intl. J. Numer

Investigation of Schottky Barriers

DTIC Science & Technology

1989-12-01

W. E. Spicer, I. Lindau, P. R. Skeath, C. Y. Su and P. W. Chye , Phys. Rev. Lett. 44, 420 (1980); W. E. Spicer, P. W. Chye , P. R. Skeath, C. Y. Su and...Kahn, D. G. Kilday, and G. Margaritondo, J. Vac. Sci. Technol. B5, 987 (1987). 8. R. Cao, K. Miyano, T. Kendelewicz, K. K. Chin , I. Lindau, and W. E

Development of a Miniature Snapshot Multispectral Imager

DTIC Science & Technology

2010-09-01

ZnS ) and SiO2, however since ITC had no prior experience with ZnS , the next best choice of TiO2 and SiO2 was selected for fabrication of dielectric...Bass, S. J.; Apsley, N. High Quality InP /InGaAs Fabry-Perrot Etalons Grown by AP MOCVD. Semicon. Sci. Technol. 1987, 2, 466–467. 13. Szipocs, R

Anthropogenic Osmium in Airborne Particles from Woods Hole, Massachusetts, USA

NASA Astrophysics Data System (ADS)

Peucker-Ehrenbrink, B.; Sen, I. S.; Geboy, N.

2012-12-01

The global geochemical cycle of osmium has been significantly disturbed by the introduction of automobile exhaust catalysts to convert noxious gas emissions into more benign forms. Anthropogenic osmium has been reported in rainwater, snow, and in the urban airborne particles from around the world to reveal global-scale osmium pollution [1, 2]. In this study, we report on the platinum group element (PGE) concentrations and osmium isotope ratios of airborne particles (PM10) collected in Woods Hole, a small coastal town in Massachusetts to better understand inputs of anthropogenic osmium to rural environments. We further investigate the use of osmium isotopes to track sources of airborne particles and support source apportionment studies on a continental scale. The samples used in this study were collected at Woods Hole Oceanographic Institution over one year (2008-2009). From this collection twelve samples for which the backward air mass trajectories have been determined were selected for osmium isotope analyses. Our results show that the osmium and platinum concentrations are an order of magnitude lower when compared to downtown Boston [2]. The average Os, Pt and Ir concentrations are 0.006±0.012, 0.019±0.023, and 0.685±0.634 pg m-3, respectively. The 187Os/188Os of the aerosols range from 0.275 to 0.788. As continental crust is radiogenic (187Os/188Os >1) and PGE ore bodies generally have unradiogenic 187Os/188Os (~0.2), the unradiogenic 187Os/188Os signature of the aerosols indicates anthropogenic contributions. With 95% of the total osmium mobilization on land being attributed to human activities [3], it is clear that human imprint on airborne particles is not restricted to urban centers with high traffic flows, but also affects rural environments. Aerosol particles that have backward air mass trajectories from the Southwest, the densely populated and industrialized Eastern seaboard, are characterized by unradiogenic osmium, while air masses from the North have radiogenic signatures. Our results suggest that 187Os/188Os has potential for source apportionment studies. [1] Rauch et al. (2005), Environ. Sci. Technol., 39, p. 9464-9470 [2] Chen et al. (2009), PNAS, 106, p. 7724-7728 [3] Sen and Peucker-Ehrenbrink (2012), Environ. Sci. Technol., dx.doi.org/10.102/es301261x

EDITORIAL: The 20th European Sectional Conference on Atomic and Molecular Physics of Ionized Gases The 20th European Sectional Conference on Atomic and Molecular Physics of Ionized Gases

NASA Astrophysics Data System (ADS)

Petrović, Zoran Lj; Marić, Dragana; Malović, Gordana

2011-03-01

This special issue consists of papers that are associated with invited lectures, workshop papers and hot topic papers presented at the 20th European Sectional Conference on Atomic and Molecular Physics of Ionized Gases (ESCAMPIG XX). This conference was organized in Novi Sad (Serbia) from 13 to 17 July 2010 by the Institute of Physics of the University of Belgrade. It is important to note that this is not a conference 'proceedings'. Following the initial selection process by the International Scientific Committee, all papers were submitted to the journal by the authors and have been fully peer reviewed to the standard required for publication in Plasma Sources Science and Technology (PSST). The papers are based on presentations given at the conference but are intended to be specialized technical papers covering all or part of the topic presented by the author during the meeting. The ESCAMPIG conference is a regular biennial Europhysics Conference of the European Physical Society focusing on collisional and radiative aspects of atomic and molecular physics in partially ionized gases as well as on plasma-surface interaction. The conference focuses on low-temperature plasma sciences in general and includes the following topics: Atomic and molecular processes in plasmas Transport phenomena, particle velocity distribution function Physical basis of plasma chemistry Plasma surface interaction (boundary layers, sheath, surface processes) Plasma diagnostics Plasma and discharges theory and simulation Self-organization in plasmas, dusty plasmas Upper atmospheric plasmas and space plasmas Low-pressure plasma sources High-pressure plasma sources Plasmas and gas flows Laser-produced plasmas During ESCAMPIG XX special sessions were dedicated to workshops on: Atomic and molecular collision data for plasma modeling, organized by Professors Z Lj Petrovic and N Mason Plasmas in medicine, organized by Dr N Puac and Professor G Fridman. The conference topics were represented in the program by 16 invited lectures, 7 selected hot topics, and 191 poster presentations. The largest number of contributed papers was submitted in Topic 5: Plasma diagnostics (37). The workshop topics were addressed by 10 invited lectures, 5 oral presentations and 7 posters. A post-conference workshop with 5 invited lectures was organized, dealing with the data needs for modeling of plasma sources of light. ESCAMPIG XX was attended by 185 scientists from 31 countries. Of the participants, 30% were PhD students (55). The list includes scientists from the USA, Japan, Australia, Mexico and other non-European countries, which indicates the truly international status of the conference. We would like to thank the authors for their efforts in preparing stimulating lectures and interesting articles for the readers of PSST, and the scientific community dealing with ionized gases, plasma sources and atomic, molecular and chemical physics of low-temperature plasmas for continued interest in the field of ESCAMPIG. We would like to thank the organizers of all previous ESCAMPIG conferences for setting the standards for organization and, in particular, the organizers of ESCAMPIG XVIII and XIX for their direct help and insight. Finally the International Scientific Committee and its chairman in particular have worked hard to select the best possible program and to keep us in line with almost 40 years of tradition and standards of the conference. Most importantly this has been the 20th conference. The quality of new papers shows maturity and new vistas in the field that has produced so much fundamental understanding of complex, non-equilibrium, even nonlinear plasmas. At the same time the field has led to some of the key technologies of modern civilization and has shown that responsible science that pays attention to its societal benefits should have no fear for its future. All critical issues studied today were presented at the meeting and only a small part is represented here. For example, discharges in liquids or above liquids were covered by several lectures represented by two papers. Verreycken et al [1] studied optical emission spectroscopy and Rayleigh scattering in discharges above water electrodes in order to measure gas temperature. At the same time Starikovsky et al [2] showed that it is possible to strike a breakdown directly in the liquid phase without gaseous evaporation or bubbles. Another key issue of present-day low-temperature plasma physics is atmospheric pressure discharges. Application of atmospheric pressure microwave plasma was considered by Belmonte et al [3] as a source for plasma-enhanced chemical vapour deposition. Strategies to produce nanosize structures and high deposition rates have also been proposed. Akishev et al [4] presented modeling results showing why spatial reproducibility of the origins of micro-discharges in a dielectric barrier discharge (DBD) is very high while the stochastic nature of the breakdown leads to jitter. Associated with the application of plasmas in many systems is control plasma chemistry. Tanarro and Herrero [5] performed measurements and modeling of dominant species in a hollow cathode discharge with variation of pressure. Dramatic changes in composition were noticed in H2, H2/Ar, and air. For example, NO becomes the second most abundant neutral under some conditions while at high mean energies H2+ ions become more abundant than H3+. Loureiro et al [6] presented the most detailed self-consistent model of discharges in N2, both pure and in mixtures with H2 and CH4. The model includes coupling of different mechanisms in the gas phase and on surfaces. A further example of detailed plasma chemistry and modeling of possible industrial applications is the work of De Bie et al [7] who studied the conversion of methane to more complex hydrocarbons and other gases in a detailed model of kinetic and plasma chemistry of a DBD reactor. Associated with plasma chemistry models but with a completely different final goal is the work of Taccogna et al [8]. They provide a detailed model of negative ion production in an ITER source of fast neutrals for heating of fusion plasma. Low-temperature plasmas have made their most significant impact through application of etching and other plasma techniques in the production of integrated circuits. Associated with this there have been several papers dealing with control of plasmas relevant for plasma etching applications. Czarnetzki et al [9] presented the modeling of an electrical asymmetry effect which allows independent control of plasma symmetry, bias and consequently properties of ions reaching the surfaces. Separate control of the flux and energy of ions from capacitively coupled plasmas, while an interesting fundamental issue, is also one of the key issues in the manufacture of integrated circuits. Makabe and Yagisawa [10] gave a detailed presentation of the top-down model of plasma devices for etching and other plasma-related nanotechnologies. Their paper presents a complex model covering atomic and molecular collisions and transport, plasma kinetics in complex geometries, and plasma interaction with surfaces with the ability to calculate the development of etched profiles, and the damage-inducing potentials within the wafer. Finally, as the basis of all modeling of plasmas, atomic and molecular collision and transport data were a much more prominent part of ESCAMPIG conferences in the past. We tried to initiate the return of elementary processes to ESCAMPIG from numerous specialized conferences by organizing a workshop on the data for modeling. Bartschat and Zatsarinny [11] gave a presentation of the foundation of the B-spline R-matrix method and a number of cross section results that extend the databases for plasma modeling of atomic gases. State-of-the-art calculations presented here focus on threshold regions of electronic excitation cross sections where complex structures exist due to resonances. These threshold regions of the excitation cross sections, however, determine the distribution function in the region of the ionization, The interface between plasma modeling and atomic physics is swarm studies, and those are based on transport theory that has recently become quite complex and versatile. Dujko et al [12] considered a Boltzmann equation solution to the transport of charged particles, especially in crossed electric and magnetic fields. Apart from indicating the necessity to include transport properties in E × B fields in plasma modeling, these results show complexity and kinetic phenomena that require kinetic models to be properly included. Finally, Makabe and Tatsumi [13] presented the structure of a comprehensive model of plasma etching devices and focused on the requirements for the atomic and collision cross section data. The winner of the W Crookes Prize was Zoltán Donkó [14] who gave a review of particle-in-cell and Monte Carlo simulation methods and presented a review of a large number of systems where he and his co-workers have applied this technique. In particular the lecture gives examples of different kinetic phenomena that arise in modeling of different plasmas. This presentation covers both applications in the control of low-pressure capacitively coupled plasmas and DC breakdown and glow discharges as well as the issues of modeling of elementary processes in the gas phase and on surfaces. Finally, to reply to Harold Pinter and his famous quote, apart from the known and the unknown there is the joy of extending the border of the 'known' and sharing it with colleagues at conferences like ESCAMPIG. Every answer that is reached opens new horizons and new realms of the 'unknown' to explore, and conferences like ESCAMPIG have proven to be a continuous source of ideas and inspiration for all colleagues within the field of low-temperature plasmas and elementary processes. We can certainly hope that the 20th ESCAMPIG was no exception in this regard. References Verreycken T, van Gessel A F H, Pageau A and Bruggeman P 2011 Plasma Sources Sci. Technol. 20 024002 Starikovsky A, Yang Y, Cho Y I and Fridman A 2011 Plasma Sources Sci. Technol. 20 024003 Belmonte T, Gries T, Cardoso R P, Arnoult R, Kosior F and Henrion G 2011 Plasma Sources Sci. Technol. 20 024004 Akishev Y, Aponin G, Balakirev A, Grushin M, Karalnik V, Petryakov A and Trushkin N 2011 Plasma Sources Sci. Technol. 20 024005 Tanarro I and Herrero V J 2011 Plasma Sources Sci. Technol. 20 024006 Loureiro J, Guerra V, Sá P A, Pintassilgo C D and Lino da Silva M 2011 Plasma Sources Sci. Technol. 20 024007 De Bie C, Martens T, van Dijk, Paulussen S, Verheyde B and Bogaerts A 2011 Plasma Sources Sci. Technol. 20 024008 Taccogna F, Minelli P, Diomede P, Longo S, Capitelli M and Schneider R 2011 Plasma Sources Sci. Technol. 20 024009 Czarnetzki U, Schulze J, Schungel E and Donkó Z 2011 Plasma Sources Sci. Technol. 20 024010 Makabe T and Yagisawa T 2011 Plasma Sources Sci. Technol. 20 024011 Bartschat K and Zatsarinny O 2011 Plasma Sources Sci. Technol. 20 024012 Dujko S, White R D, Petrovic Z Lj and Robson R E 2011 Plasma Sources Sci. Technol. 20 024013 Makabe T and Tatsumi T 2011 Plasma Sources Sci. Technol. 20 024014 Donkó Z 2011 Plasma Sources Sci. Technol. 20 024001

Green engineering education through a U.S. EPA/academia collaboration.

PubMed

Shonnard, David R; Allen, David T; Nguyen, Nhan; Austin, Sharon Weil; Hesketh, Robert

2003-12-01

The need to use resources efficiently and reduce environmental impacts of industrial products and processes is becoming increasingly important in engineering design; therefore, green engineering principles are gaining prominence within engineering education. This paper describes a general framework for incorporating green engineering design principles into engineering curricula, with specific examples for chemical engineering. The framework for teaching green engineering discussed in this paper mirrors the 12 Principles of Green Engineering proposed by Anastas and Zimmerman (Environ. Sci. Technol. 2003, 37, 94A-101A), especially in methods for estimating the hazardous nature of chemicals, strategies for pollution prevention, and approaches leading to efficient energy and material utilization. The key elements in green engineering education, which enlarge the "box" for engineering design, are environmental literacy, environmentally conscious design, and beyond-the-plant boundary considerations.

Combustion of Alane and Aluminum with Water for Hydrogen and Thermal Energy Generation

DTIC Science & Technology

2010-01-01

Herr, Green Rocket Propulsion by Reaction of Al and Mg Powders and Water, AIAA 2004-4037, 2004. [9] J.L. Sabourin , G.A. Risha, R.A. Yetter, S.F. Son...Wiley and Sons, Inc., 1992. [32] G.A. Risha, J.L. Sabourin , V. Yang, R.A. Yetter, S.F. Son, B.C. Tappan, Combust. Sci. Technol. 180 (2008) 2127–2142

Recent Naval Postgraduate School Publications.

DTIC Science & Technology

1985-09-30

of the performance of a new storm tracking methodology Prepared for Naval Environmental Prediction Res. Facility Monterey, Calif., Naval Postgraduate...Aerospace Sci. Mtg., Jr’., 1983. Sarpkaya, T; Storm , M A ydrodynamic forces from combined wave and current flow on smooth and rough circular cylinders...Houston, Tx., May, 1982. IN Proc 1982 Offshore Technol. Conf., vol. 1, p.731-736, (1982). Sarpkaya, T; Storm , M A ydrodynamic forces from combined wave

A New Family of Schroder's Method and Its Variants Based on Power Means for Multiple Roots of Nonlinear Equations

ERIC Educational Resources Information Center

Kanwar, V.; Sharma, Kapil K.; Behl, Ramandeep

2010-01-01

In this article, we derive one-parameter family of Schroder's method based on Gupta et al.'s (K.C. Gupta, V. Kanwar, and S. Kumar, "A family of ellipse methods for solving non-linear equations", Int. J. Math. Educ. Sci. Technol. 40 (2009), pp. 571-575) family of ellipse methods for the solution of nonlinear equations. Further, we introduce new…

Reactive high power impulse magnetron sputtering

NASA Astrophysics Data System (ADS)

Gudmundsson, J. T.; Magnus, F.; Tryggvason, T. K.; Sveinsson, O. B.; Olafsson, S.

2012-10-01

Here we discuss reactive high power impulse magnetron sputtering sputtering (HiPIMS) [1] of Ti target in an Ar/N2 and Ar/O2 atmosphere. The discharge current waveform is highly dependent on both the pulse repetition frequency and discharge voltage. The discharge current increases with decreasing frequency or voltage. This we attribute to an increase in the secondary electron emission yield during the self-sputtering phase of the pulse, as nitride [2] or oxide [3] forms on the target. We also discuss the growth of TiN films on SiO2 at temperatures of 22-600 ^oC. The HiPIMS process produces denser films at lower growth temperature and the surface is much smoother and have a significantly lower resistivity than dc magnetron sputtered films on SiO2 at all growth temperatures due to reduced grain boundary scattering [4].[4pt] [1] J. T. Gudmundsson, N. Brenning, D. Lundin and U. Helmersson, J. Vac. Sci. Technol. A, 30 030801 (2012)[0pt] [2] F. Magnus, O. B. Sveinsson, S. Olafsson and J. T. Gudmundsson, J. Appl. Phys., 110 083306 (2011)[0pt] [3] F. Magnus, T. K. Tryggvason, S. Olafsson and J. T. Gudmundsson, J. Vac. Sci. Technol., submitted 2012[0pt] [4] F. Magnus, A. S. Ingason, S. Olafsson and J. T. Gudmundsson, IEEE Elec. Dev. Lett., accepted 2012

Advanced Coatings from Natural-Based Polymers for Metals

DTIC Science & Technology

2000-07-01

Polyimide Interfaces," J. surfaces using a simple dipping-withdrawing coating Vac. Sci. Technol., 3,1390 (1985).converted into the solid layers by heat...Tang, C.H., "Interface Reaction During Metalliza- more, the Al metal in the substrate favorably interacted tion of Cured Polyimide : An XPS Study," 1...property together with its biocompatability was the reason why CS is widely used in biomedical applications, for example, a bacteriostatic agent, a

Nitrogen Plasma Optimization for High-Quality Dilute Nitrides

DTIC Science & Technology

2005-02-01

Available online 1 February 2005Abstract Growth of GaInNAs by molecular beam epitaxy (MBE) generally requires a nitrogen plasma, which complicates growth...InGaAs and InGaAsP lasers. This paper addresses several of the challenges of plasma-assisted molecular beam epitaxy (MBE) of high-quality dilute nitrides...A.L. Holmes, Using beam flux monitor as Langmuir probe for plasma-assisted molecular beam epitaxy , J. Vac. Sci. Technol. B, in press.

Analysis of reversibility and reaction products of glyoxal uptake onto ammonium sulfate aerosol

NASA Astrophysics Data System (ADS)

Galloway, M. M.; Chhabra, P. S.; Chan, A. W.; Surratt, J. D.; Kwan, A. J.; Wennberg, P. O.; Flagan, R. C.; Seinfeld, J. H.; Keutsch, F. N.

2009-04-01

Glyoxal, the smallest alpha-dicarbonyl, is an oxidation product of both biogenic and anthropogenic volatile organic compounds (Fu et al. JGR 113, D15303, 2008). Despite its low molecular weight, its role in secondary organic aerosol (SOA) formation has gained interest and a recent study suggested that it accounts for more than 15% of SOA in Mexico City (Volkamer et al. GRL 34, L19807, 2007). Despite numerous previous studies, questions remain regarding the processes controlling glyoxal uptake onto aerosol, including the role of acid catalysis, degree of reversibility, and identity of aerosol phase reaction products. We present results of chamber aerosol studies (Galloway et al. ACPD 8, 20799, 2008) and laboratory studies of bulk samples aimed at improving the understanding of these processes, in particular formation of oligomers and organosulfates of glyoxal, as well as the formation of imidazoles (carbon-nitrogen containing heterocyclic aromatic compounds) under dark and irradiated conditions. The relevance of these classes of reaction products extends beyond glyoxal, as evidence of oligomers and organosulfates other than those of glyoxal have been found in ambient aerosol (Surratt et al. JPCA 112, 8345, 2008; Denkenberger et al. Environ. Sci. Technol. 41, 5439, 2007). Experiments in which a chamber air mass was diluted after equilibration of glyoxal uptake onto ammonium sulfate seed aerosol (relative humidity 60% and glyoxal mixing ratios of 25-200 ppbv) shows that under these conditions uptake is reversible. The most important condensed phase products are hydrated oligomers of glyoxal, which are also formed reversibly under these conditions. Our studies show that organosulfates were not formed under dark conditions for neutral or acidified aerosol; similarly, Minerath et al. have recently shown that formation of a different class of organosulfates (alkyl sulfates) also proceeds very slowly even under acidic conditions (Environ. Sci. Technol. 42, 4410, 2008). The masses assigned to sulfate esters in previous work (Liggio et al. Environ. Sci. Technol. 39, 1532, 2005) via low resolution AMS studies were assigned as glyoxal oligomers in our study via high resolution AMS spectra. However, organosulfates were identified under irradiated conditions, and we present attempts to identify the specific species via comparison with lab synthesized organosulfates. The influence of irradiation on organosulfate formation is still under investigation. Under irradiated conditions we see clear evidence for active oxidative photochemistry. The aerosol phase becomes increasingly oxidized and oxidation products, such as organic acids, similar to those observed in studies using bulk samples by Carlton et al. (Atmos. Environ. 41, 7588, 2007) are formed. Overall uptake is reduced under our experimental conditions, likely due to increasing temperature and decreasing relative humidity. We also report observation of imidazoles (carbon-nitrogen containing aromatic heterocycles) resulting from reaction of glyoxal with the nitrogen component of the ammonium sulfate seed aerosol. The imidazoles form irreversibly under dark and irradiated conditions, in ammonium sulfate and acidified ammonium sulfate (pH~1) aerosol. The molecular framework of imidazoles is very stable as a result of the aromaticity. The primary imidazole product, which has a low vapor pressure estimated at 0.0014 Torr, is predicted to be present as a (protonated) cation, owing to its basicity (pKB = 7). It is thus likely not a candidate for repartitioning to the gas phase. Evidence for participation of ammonium in reactions with glyoxal using bulk samples has recently been reported by Noziere et al. (JPCA 113, 231, 2008; ACPD 9, 1, 2009). This study reveals the complex chemistry occurring within ammonium sulfate seed aerosol even for systems with greatly reduced complexity compared to atmospheric aerosol. The results increase our understanding of the contribution of glyoxal to SOA formation processes. More specifically, these results provide valuable insights into important aerosol processes, such as organosulfate and oligomer formation, as well as the formation of aromatic nitrogen containing heterocycles from reaction of a carbonyl with ammonium sulfate aerosol.

Rapid Formation of Acrylated Microstructures by Microwave-Induced Thermal Crosslinking

DTIC Science & Technology

2010-01-01

Kagawa, M. Okubo, Chem. Rev. 2008, 108, 3747. [10] C. O. Kappe, D. Dallinger, Nature Rev. Drug Disc. 2006, 5, 51. [11] R. Hoogenboom , U. S. Schubert...of Electronic Imaging 2004, 13. [24] R. M. Paulus, C. R. Becer, R. Hoogenboom , U. S. Schubert, Aust. J. Chem. 2009, 62, 254. [25] S. S. Cutie, D. E...Kohn, Macromolecules 1992, 25, 4476. [27] H. Zhang, R. Hoogenboom , M. Meier, U. Schubert, Meas. Sci. Technol. 2005, 16, 203. 13

Joint Services Electronics Program.

DTIC Science & Technology

1986-09-30

IEEE Computer Society Conference on Trends and Aplications , Gaithersburg, MD, 57-62, May 1983. R.W. Miksad, D.W. Choi and E.J. Powers, "Application of...Estimators for Weakl Nonlinear Esti’mation Problems, M.S. Thesis , Dept. of Electrica Engineering, University of Texas at Austin, May 1982. 7 %- (Page...Chen, J. Vac. Sci. Technol. 17,911 (1980). 6. N.I. Cho, Masters Thesis , unpublished. 7. EI-Saied M. Aly and J.P. Stark, J. Appl. Phys. 53(4), 3063

Scanning Tunneling Microscopy, Atomic Force Microscopy, and Related Techniques

DTIC Science & Technology

1992-02-26

92. (B47) Fujui, T.; Suzuki, MA.; Miyashita, MA.; Yamaguchi, M.; Onuki , T.; Nakamura, H .; Matsubara, T.; Yamada, H .; Nakayamia, K. J. Vac. Sd...and seven deflection detection systems (A 15). (Al) Binnig, G.; Rohrer, H .; Gerber, Ch.; Weibel, E. Phys. Rev. Lett. 1982, 49, 57. (A2) Ray, M.A...J. J. Vac Sci. Technol. A 1ඣ, 9, 44-50. (AS) Scanning Tunneling Microscopy and Related Methods; Behm, RJ., Garcia, N., Rohrer, H ., Eds.; NATO ASI

Enhanced etching of tin-doped indium oxide due to surface modification by hydrogen ion injection

NASA Astrophysics Data System (ADS)

Li, Hu; Karahashi, Kazuhiro; Friederich, Pascal; Fink, Karin; Fukasawa, Masanaga; Hirata, Akiko; Nagahata, Kazunori; Tatsumi, Tetsuya; Wenzel, Wolfgang; Hamaguchi, Satoshi

2018-06-01

It is known that the etching yield (i.e., sputtering yield) of tin-doped indium oxide (ITO) by hydrocarbon ions (CH x +) is higher than its corresponding physical sputtering yield [H. Li et al., J. Vac. Sci. Technol. A 33, 060606 (2015)]. In this study, the effects of hydrogen in the incident hydrocarbon ion beam on the etching yield of ITO have been examined experimentally and theoretically with the use of a mass-selected ion beam system and by first-principles quantum mechanical (QM) simulation. As in the case of ZnO [H. Li et al., J. Vac. Sci. Technol. A 35, 05C303 (2017)], mass-selected ion beam experiments have shown that the physical sputtering yield of ITO by chemically inert Ne ions increases after a pretreatment of the ITO film by energetic hydrogen ion injection. First-principles QM simulation of the interaction of In2O3 with hydrogen atoms shows that hydrogen atoms embedded in In2O3 readily form hydroxyl (OH) groups and weaken or break In–O bonds around the hydrogen atoms, making the In2O3 film less resistant to physical sputtering. This is consistent with experimental observation of the enhanced etching yields of ITO by CH x + ions, considering the fact that hydrogen atoms of the incident CH x + ions are embedded into ITO during the etching process.

On the modified Tabor parameter for the JKR-DMT transition in the presence of a liquid meniscus.

PubMed

Xu, Dewei; Liechti, Kenneth M; Ravi-Chandar, K

2007-11-15

The JKR, DMT, Maugis models and Tabor parameter for contact under normal loading have been developed based mainly on solid-solid (van der Waals) interactions. In this case, the characteristic length scale for the adhesive forces in the Tabor parameter is the equilibrium interatomic spacing. However, for contact in humid environments, where a liquid meniscus may be present, capillary forces with a longer force range related to the Kelvin radius dominate. Fogden and White [J. Colloid Interface Sci. 138 (1990) 414] introduced a parameter that includes the Kelvin radius for the JKR-DMT transition. This topic was also addressed by Maugis and Gauthier-Manuel [J. Adhes. Sci. Technol. 8 (1994) 1311] who included capillary effects within the frame work that Maugis had previously established. The parameters introduced by Fogden and White and Maugis and Gauthier-Manuel can be viewed as a modified Tabor parameter for the JKR-DMT transition. In the present work, the Kelvin equation linking the Kelvin radius and the relative humidity was explicitly included in the modified Tabor parameter. This provided a quantitative description of the JKR-DMT transition in terms of the relative humidity. This parameter was examined via load and contact radius measurements, where the latter were obtained from Bowden and Tabor's assumption that the friction force f=tauA. The friction experiments were conducted at two different humidity levels using a newly-developed mesoscale friction tester (MFT), which provides a very wide range of contact radii. The modified Tabor parameter was used to reexamine data from pull-off experiments in water and cyclohexane vapor environments [L.R. Fisher, J.N. Israelachvili, Colloids Surf. 3 (1981) 303 and H.K. Christenson, J. Colloid Interface Sci. 121 (1988) 170]. Finally, guidelines are presented for the appropriate choice of contact mechanics models to be used in interpreting data from SFA and AFM experiments in humid environments.

Label-free carbon particulates detection in bio (medical) settings (Conference Presentation)

NASA Astrophysics Data System (ADS)

Steuwe, Christian; Bové, Hannelore; vandeVen, Martin J.; Ameloot, Marcel; Roeffaers, Maarten B. J.

2017-02-01

The adverse health effects of particulate matter exposure are a generally accepted concern. Dramatic statistical figures suggest that fine dust is a main environmental risk in Europe and can be held accountable for hundreds of thousands of deaths per year [1]. Locating and tracking these nanometer sized particles, however, is not straight forward: In epidemiological and toxicology research only measurements based on labels [2] such as radionuclide markers have been applied. In this paper we present a direct, label-free optical contrast mechanism to detect carbon nanoparticles immersed in aqueous environments [3]. The virtue of this technique is its ability to perform in body fluids such as urine but also in cells and tissues. The mechanism is based on white light (WL) generation upon illumination with femtosecond pulsed near-infrared and is therefore non-incandescence related. We demonstrate the technique in various biological settings with dry and suspended carbon black particles (CB), a widely used model compound for soot [4]. Our approach allows for the unequivocal localization of CB alongside of common fluorophores and markers and can be performed on multiphoton laser-scanning microscopy platforms, a system commonly available in research laboratories. [1] European Environment Agency (2015). Press release. [2] Kong et al. Int. J. Mol. Sci. 2013, 14, (11), 22529-22543 [3] Bové and Steuwe et al. Nano letters, 2016, (16) , pages 3173-3178 [4] Arnal et al. Combust. Sci. Technol. 2012, 184, (7-8), 1191-1206.

Water Temperature and Concentration Measurements Within the Expanding Blast Wave of a High Explosive

DTIC Science & Technology

2011-03-15

Please scroll down to see the full text article. 2011 Meas. Sci. Technol. 22 045601 (http://iopscience.iop.org/0957-0233/22/4/045601) Download...Glumac [15] recently demonstrated the use of a Nd:YAG pumped dye laser for absorption measurements (single shot per detonation experiment, 10 ns...weighing 2.6 or 21 g for the 12.7 and 25.4 mm cylinders, respectively. A thin layer of vacuum grease was applied to the face of the detonator so that the

Laser Surface Melting of Stainless Steel Anodes for Reduced Hydrogen Outgassing (Postprint)

DTIC Science & Technology

2016-12-29

including baking [8– 12], vacuum baking [8,11,13,14], polishing [8,14], and surface treatments to create oxide or other protective surface films. Elec...quantity [15] and may necessitate an additional bake to thoroughly degas the surface [8]. The purpose of the work described here was to determine the...9] M. Bernardini, Air bake -out to reduce hydrogen outgassing from stainless steel, J. Vac. Sci. Technol. A Vacuum, Surfaces, Film 16 (1998) 188–193.4

Interface-induced localization in AlSb/InAs heterostructures

NASA Astrophysics Data System (ADS)

Shaw, M. J.; Briddon, P. R.; Jaros, M.

1995-12-01

The existence of localized states at perfect InSb-like interfaces in AlSb/InAs superlattices is predicted from ab initio pseudopotential calculations. Localized states are predicted in both the valence and conduction bands, the former being identifiable with the interface states proposed by Kroemer, Nguyen, and Brar [J. Vac. Sci. Technol. 10, 1769 (1990)]. The existence of these interface localized states is invoked to explain the reported experimental dependence of the band gap upon interface types in such superlattices.

Quantifying the decadal changes of PM2.5 over New York through a combination of satellite, model and in-situ measurements

NASA Astrophysics Data System (ADS)

Jin, X.; Fiore, A. M.; Curci, G.; Lyapustin, A.; Wang, Y.; Civerolo, K.; Ku, M.; van Donkelaar, A.; Martin, R.

2017-12-01

Ambient exposure to fine particulate matter (PM2.5) is one of the top global health concerns. Efforts have been made to regulate PM2.5 precursor emissions across the U.S.A, which are expected to mitigate the air pollution related health impacts. However, quantifying the health outcomes from emission controls requires robust estimates of PM2.5 exposures that accurately describe the spatial and temporal variability of PM2.5. Satellite remote sensing offers the potential to fill the gaps of the sparse, limited sampling of in situ measurement networks and is increasingly being used in health assessments. We provide new estimates of PM2.5 over New York State with 1 km spatial resolution that use Multi-Angle Implementation of Atmospheric Correction (MAIAC) AOD and a regional air quality model (CMAQ) to estimate the AOD-PM2.5 scaling factors. Next, we evaluate three major sources of uncertainties of satellite-derived PM2.5 data and their impacts on the derived decadal changes: 1) satellite retrieval of AOD, 2) optical properties of the particles, 3) relationships between the aerosol burden in the planetary boundary layer and full atmospheric column. Finally, we analyze the decadal changes of PM2.5 over New York State using the newly developed PM2.5 data, alongside four other PM2.5 estimates including satellite-derived PM2.5 developed by van Donkelaar et al. (2015), statistical land use regression developed by Beckerman et al. (2013), CMAQ simulations, and a Bayesian fusion of CMAQ and ground-based measurements. By evaluating the decadal changes of PM2.5 from multiple datasets over areas with dense (e.g. New York City area) and sparse ground-based measurements (e.g. upstate New York), we evaluate the extent to which satellite remote sensing could help better quantify the health outcomes of emission controls. References: Beckerman et al., (2013), A Hybrid Approach to Estimating National Scale Spatiotemporal Variability of PM2.5 in the Contiguous United States, Environ. Sci. Technol., 47(13), 7233-7241. van Donkelaar et al. (2015), High-Resolution Satellite-Derived PM2.5 from Optimal Estimation and Geographically Weighted Regression over North America, Environ. Sci. Technol., 49(17), 10482-10491.

Effect of ionic strength on barium transport in porous media

NASA Astrophysics Data System (ADS)

Prigiobbe, V.; Ye, Z.

2017-12-01

Hydraulic fracturing (or fracking) is a well stimulation technique used to extract resourcesfrom a low permeability formation. During the operation large volumes of brine, rich ofhazardous chemicals, are produced. Spills of brine from a well or a pit might negativelyimpact underground water resources and one of the major concerns is for the migrationof radionuclides, such as, e.g., radium (Ra2+), into the shallow subsurface [1]. However, thetransport behaviour of Ra2+ through a reactive porous medium under conditions typical of abrine, i.e., high salinity, is not well understood, yet. Here, a study on the transport behaviour ofbarium (Ba2+, congener of radium) through a porous medium containing a common mineralsuch as goethite (FeO(OH)) is presented [2]. Batch and column flood tests were carried out atconditions resembling the produced water, i.e., large values of ionic strength (I), namely, 1to 3 mol/kg. The measurements were described with the triple layer surface complexationmodel coupled with the Pitzer activity coefficient method and a reactive transport model,in the case of the transport tests. The experimental results show that the adsorption of Ba2+onto FeO(OH) increases with pH but decreases with I and it becomes negligible at the brineconditions. Moreover, even if isotherms show adsorption at large I, at the same conditionsduring transport, Ba2+ travels without retardation through the FeO(OH) porous medium. The triple layer model agrees very well with all batch data but it cannot capture wellthe transport test, in particular, at large I values (Figure 1). This may suggest that thechemical reactions at the solid-liquid interface cannot describe well the adsorption of Ba2+onto FeO(OH) at large salinity. Finally, observations in this study suggest that in the case of a produced water spill, barium and potentially its congeners, namely, radium, calcium,magnesium, and strontium, contained in the brine may travel at the average flow velocity through a soil containing iron oxide minerals. References[1] Patterson et al. Environ. Sci. Technol. 2017, 51, 2563-2573.[2] Ye, Z. and Prigiobbe, V. In preparation for: Environ. Sci. Technol. 201X. Figure 1. Measurements and simulations of Ba2+ transport tests for experiments performedusing (a) NaCl = 0 and (b) NaCl = 1 mole/kg.

Response to Julian et al. (2015) "comment on and reinterpretation of Gabriel et al. (2014) 'fish mercury and surface water sulfate relationships in the everglades protection area'".

PubMed

Gabriel, Mark C; Axelrad, Don; Orem, William; Osborne, Todd Z

2015-06-01

The purpose of this forum is to respond to a rebuttal submitted by Julian et al., Environ Manag 55:1-5, 2015 where they outlined their overall disagreement with the data preparation, methods, and interpretation of results presented in Gabriel et al. (Environ Manag 53:583-593, 2014). Here, we provide background information on the research premise presented in Gabriel et al. (Environ Manag 53:583-593, 2014) and provide a defense for this work using five themes. In spite of what Julian et al. perceive as limitations in the sampling methods and analytical tools used for this work, the relationships found between fish total mercury and surface water sulfate concentrations in Gabriel et al. (Environ Manag 53:583-593, 2014) are comparable to relationships between pore water methylmercury (MeHg) and pore water sulfate found in past studies indicating that sulfate is important to MeHg production and bioaccumulation in the Everglades. Julian et al. state "…there is no way to justify any ecosystem-wide sulfur strategy as a management approach to reduce mercury risk in the (Everglades) as suggested by Gabriel et al. (Environ Manag 53:583-593, 2014), Corrales et al. (Sci Tot Environ 409:2156-2162, 2011) and Orem et al. (Rev Environ Sci Technol 41 (S1):249-288, 2011)." We disagree, and having stated why sulfate input reduction to the Everglades may be the most effective means of reducing mercury in Everglades fish, it is important that research on sulfur and mercury biogeochemistry continues. If further studies support the relationship between sulfate loading reduction and MeHg reduction, sulfur mass balance studies should commence to (1) better quantify agricultural and connate seawater sulfate inputs and (2) define opportunities to reduce sulfate inputs to the Everglades ecosystem.

The "Mendel syndrome" in science: durability of scientific literature and its effects on bibliometric analysis of individual scientists.

PubMed

Costas, Rodrigo; van Leeuwen, Thed N; van Raan, Anthony F J

2011-10-01

The obsolescence and "durability" of scientific literature have been important elements of debate during many years, especially regarding the proper calculation of bibliometric indicators. The effects of "delayed recognition" on impact indicators have importance and are of interest not only to bibliometricians but also among research managers and scientists themselves. It has been suggested that the "Mendel syndrome" is a potential drawback when assessing individual researchers through impact measures. If publications from particular researchers need more time than "normal" to be properly acknowledged by their colleagues, the impact of these researchers may be underestimated with common citation windows. In this paper, we answer the question whether the bibliometric indicators for scientists can be significantly affected by the Mendel syndrome. Applying a methodology developed previously for the classification of papers according to their durability (Costas et al., J Am Soc Inf Sci Technol 61(8):1564-1581, 2010a; J Am Soc Inf Sci Technol 61(2):329-339, 2010b), the scientific production of 1,064 researchers working at the Spanish Council for Scientific Research (CSIC) in three different research areas has been analyzed. Cases of potential "Mendel syndrome" are rarely found among researchers and these cases do not significantly outperform the impact of researchers with a standard pattern of reception in their citations. The analysis of durability could be included as a parameter for the consideration of the citation windows used in the bibliometric analysis of individuals.

Examining the relationship between mercury and organic matter in lake sediments along a latitudinal transect in subarctic Canada

NASA Astrophysics Data System (ADS)

Galloway, Jennifer M.; Sanei, Hamed; Parsons, Michael; Swindles, Graeme T.; Macumber, Andrew L.; Patterson, R. Timothy; Palmer, Michael; Falck, Hendrik

2016-04-01

The accumulation of Hg in aquatic environments at both high and low latitudes can be controlled by organic matter through algal scavenging, thus complicating the interpretation of historical Hg profiles in lake sediments1,2,3. However, other recent studies suggest that algal scavenging is not important in governing Hg flux to sediments4, in some cases because of dilution by inorganic materials5. This study examines relationships between Hg and organic matter (OM) in over 100 lakes located between 60.5 and 65.4 °N and crossing the latitudinal tree-line in subarctic Canada. The latitudinal gradient approach in our study offers an opportunity to better understand climate and environmental controls on OM accumulation and its role in influencing Hg deposition in subarctic lacustrine environments. We used Rock Eval 6 pyrolysis to determine total organic carbon (TOC%), S1 (soluble OM consisting of degradable lipids and algal pigments), S2 (OM derived from highly aliphatic biomacromolecule structure of algal cell walls), and S3 (OM dominated by carbohydrates, lignins, and plant materials). Total Hg in sediments was measured using thermal decomposition, amalgamation, and atomic absorption spectrophotometry. In these lake sediments, S2 composes the majority of TOC (Pearson's r = 0.978, p<0.01) and is negatively correlated with latitude (r = -0.475, p<0.01). S1 and TOC are also negatively correlated with latitude (r = -0.237 and -0.452, respectively, p<0.01). These associations are interpreted to reflect less autochthonous OM production and proportionally higher allochthonous OM input to more northern lakes (oxygen index vs. latitude r = 0.371, p<0.01). Similar to previous studies1,2,3 Mercury displays a significant positive association with S1 (r = 0.556, p<0.01), S2 (r = 0.518, p<0.01), and TOC (r = 0.504, p<0.01),supporting the hypothesis that OM influences Hg accumulation in subarctic lake sediments. References 1Sanei, H., Goodarzi, F. 2006. Relationship between organic matter and mercury in recent lake sediment: the physical-geochemical aspects. Appl Geochem 21: 1900-12. 2Outridge, P.M., Sanei, H., Stern, G.A., Hamilton, P.B., Goodarzi, F. 2007. Evidence for control of mercury accumulation rates in Canadian high Arctic lake sediments by variations of aquatic primary productivity. Environ Sci Technol 41: 5259-65. 3Wu, F., Zu, L., Liao, H., Guo, F., Zhao, X., Giesy, J. 2013. Relationship between mercury and organic carbon in sediment cores from Lakes Qinghai and Chenghai, China. J Soils Sediments 13: 1084-1092.4Kirk, J.L., Muir, D.C.G., Antoniades, D., Douglas, M.S.V., Evans, M.S., Jackson, T.A., Kling, H., Lamoureux, S., Lim, D.S.S., Pienitz, R., Smol, J.P., Stewart, K., Wang, X., Yang, F. 2011. Response to comment on climate change and mercury accumulation in Canadian high and subarctic lakes. Environ Sci Technol 45: 6705-06.5Deison, R., Smol, J.P., Kokelj, S.V., Pisaric, M.F.J., Kimpe, L.E., Poulain, A.J., Sanei, H., Theinpoint, J.R., Blais, J.M. 2012. Spatial and temporal assessment of mercury and organic matter in thermokarst affected lakes of the Mackenzie Delta Uplands, NT, Canada. Environ Sci Tech 46: 8748-55.

Ultrashort Pulse Inscription of Photonic Structures in ZnSe and GaAs for Mid Infrared Applications

DTIC Science & Technology

2010-08-01

structure shown in Figure 2 is an example of a type I waveguide where guiding occurs in the modified region created at the focus of the fabrication beam...turn produces a refractive index change. The end facet cross sections of type I and type II waveguide structures are illustrated below in Figure 2 and...and E. Mazur, Meas. Sci. Technol. 12, 1784 (2001). 4) A. G. Okhrimchuk, V. K. Mezentsev, H. Schmitz, M. Dubov, and I . Bennion, Laser Phys. 19 1415

Interface Properties of Wide Bandgap Semiconductor Structures

DTIC Science & Technology

1994-06-01

resistive than silicides and their chemistry with 126I I Si-based materials more complex. However, in a series of studies, M. 0. Aboelfotoh et al. have...clarification of these issues. CuGe contacts on Ge:GaN and Mg:GaN. To date, the properties of Cu3Ge films have been documented by Aboelfotoh et al., but the...Martin, V. Malhotra, and J. E. Mahan, J. Vac. Sci. Technol. B 3, 836 (1985). 25. L. Krusin-Elbaum and M. 0. Aboelfotoh , Appl. Phys. Lett. 58(12), 1341

The Application of Advanced Diagnostics to the Study of Non-Equilibrium Air Plasmas

DTIC Science & Technology

2002-09-01

26. The 10-, 100-, and 1000-µs pulses monotonically increase with N2 dilution, and the shapes agree with the calculation of Garscadden and Nagpal ...efficiency of H2 in a steady-state H2–N2 gas-mixture discharge has been measured by Nagpal et al.,24 and their analysis of the energy balance showed that...Bletzinger, J. Appl. Phys. 82, 4772 (1997). 49 23. A. Garscadden and R. Nagpal , Plasma Sources Sci. Technol. 4, 268 (1995). 24. R. Nagpal , B. N

Chemical Bonding, Interdiffusion and Electronic Structure at InP, GaAs, and Si-Metal Interfaces.

DTIC Science & Technology

1984-01-15

1980) 420. 37. A. Hiraki , K. Shuts. F. Kim. W. Kammura. and W. Iwami, A\\ppl. Phys. Len. 31 (1977) 611, and references therein. 38. L.J. Brilison, C.F...and references therein. 5. A. Hiraki , M.A. Nicolet, and J.W. Mayer, Appi. Phys. Lett. !a, 178 (1971); A. Hiraki , K. Shuto, F. Kim, W. Kammura, and W...IZ, 1005 (1980) and references therein. 7. T. Narusawa, K. Kinoshita, W.M. Gibson, and A. Hiraki , J. Vac. Sci. Technol.. Ia. 872 (1981). 8. J

Encapsulation and Annealing of Sulfur and Selenium Implanted Gallium Arsenide

DTIC Science & Technology

1978-03-24

Nisse, and F. L. Vook, Plenum Press, New York 1974 (p. 141). 3. J. A. Borders and S. T. Picraux, Proc. IEEE 62, 1224 (1974). 4. A. Hiraki , M. A. Nicolet...and J. W. Mayer, Appl. Phys. Letters 18, 178 (1971). 5. A. Hiraki and E. Lugujjo, J. Vacuum Sci. Technol. 9, 155 (1972). 6. A. Hiraki , E. Lugujjo, M...A. Nicolet, and J. W. Mayer, phys. stat. sol (a) 7, 401 (1971). 7. A. Hiraki , E. Lugujjo, and J. W. Mayer, J. Appl. Phys. 43, 3643 (1972). 8. J. M

Modeling spatially- and temporally-explicit water stress indices for use in life cycle assessment

NASA Astrophysics Data System (ADS)

Scherer, L.; Venkatesh, A.; Karuppiah, R.; Usadi, A.; Pfister, S.; Hellweg, S.

2013-12-01

Water scarcity is a regional issue in many areas across the world, and can affect human health and ecosystems locally. Water stress indices (WSIs) have been developed as quantitative indicators of such scarcities - examples include the Falkenmark indicator, Social Water Stress Index, and the Water Supply Stress Index1. Application of these indices helps us understand water supply and demand risks for multiple users, including those in the agricultural, industrial, residential and commercial sectors. Pfister et al.2 developed a method to calculate WSIs that were used to estimate characterization factors (CFs) in order to quantify environmental impacts of freshwater consumption within a life cycle assessment (LCA) framework. Global WSIs were based on data from the WaterGAP model3, and presented as annual averages for watersheds. Since water supply and demand varies regionally and temporally, the resolution used in Pfister et al. does not effectively differentiate between seasonal and permanent water scarcity. This study aims to improve the temporal and spatial resolution of the water scarcity calculations used to estimate WSIs and CFs. We used the Soil and Water Assessment Tool (SWAT)4 hydrological model to properly simulate water supply in different world regions with high spatial and temporal resolution, and coupled it with water use data from WaterGAP3 and Pfister et al.5. Input data to SWAT included weather, land use, soil characteristics and a digital elevation model (DEM), all from publicly available global data sets. Potential evapotranspiration, which affects water supply, was determined using an improved Priestley-Taylor approach. In contrast to most other hydrological studies, large reservoirs, water consumption and major water transfers were simulated. The model was calibrated against observed monthly discharge, actual evapotranspiration, and snow water equivalents wherever appropriate. Based on these simulations, monthly WSIs were calculated for a few model regions (including Africa and North America). These WSIs were used to estimate revised CFs for freshwater consumption to be used in LCAs. Future work will extend results to a global scale. References 1. Brown, A., Matlock, M., 2011. A Review of Water Scarcity Indices and Methodologies, University of Kansas, The Sustainability Consortium, White Paper #106. 2. Pfister, S., Koehler, A., Hellweg, S., 2009. Assessing the Environmental Impacts of Freshwater Consumption in LCA. Environ. Sci. Technol. 43 (11), 4098-4104. 3. Alcamo, J.; Doll, P.; Henrichs, T.; Kaspar, F.; Lehner, B.; Rosch, T.; Siebert, S. Development and testing of the WaterGAP 2 global model of water use and availability Hydrol. Sci. J. 2003, 48 (3) 317- 337. 4. Arnold, J.G., Srinivasan, R., Muttiah, R.S., Allen, P.M., 1999. Continental scale simulation of the hydrologic balance. J. Am.Water Resour. Assoc. 35 (5), 1037-1051. 5. Pfister, S., Bayer, P., Koehler, A., Hellweg, S., 2011. Environmental Impacts of Water Use in Global Crop Production: Hotspots and Trade-Offs with Land Use. Environ. Sci. Technol. 45 (13), 5761- 5768.

Reactive Gaseous Mercury Formation Over The North Pacific Ocean: Influence Of Environmental Parameters On Elemental Mercury Oxidation In The Marine Boundary Layer

NASA Astrophysics Data System (ADS)

Laurier, F. J.

2002-12-01

Global mercury models have identified wet and dry particle deposition and evasion of dissolved gaseous mercury from the ocean and from land as key controls over global mercury cycling (1,2). Recent ocean studies (3,4) however, have indicated that estimated mercury evasion rates from the ocean substantially exceed estimated deposition. Oxidized reactive gaseous mercury species (RGHg) are now known to play a major role in the global mercury cycle (2,5). RGHg species are water-soluble, exhibit a much shorter atmospheric lifetime than elemental mercury, and contribute to a large extent to atmospheric mercury deposition (2,3,6). Although recent global mercury models have accounted for the dry deposition of RGHg derived from point source emissions (6,7), the formation and deposition of RGHg in remote areas have not been incorporated. We suggest that the oxidation of elemental mercury over the ocean, by gas phase or heterogeneous reactions, is an important part the global mercury cycle. In agreement with previous studies (3,8,9) our recent data from atmospheric collections over the North Pacific Ocean support the notion of enhanced oxidation in the marine boundary layer. Our results show an inverse correlation between RGHg production and ozone, and a diurnal cycle with highest concentrations during periods of highest UV irradiation. In addition, the relationship between RGHg and other parameters measured during the cruise will be discussed. Our results clearly show that RGHg deposition to the ocean must be an important Hg source, and a crucial part of the global Hg cycle. (1) Mason R.P., Fitzgerald W.F., and Morel F.M.M. (1994), The biogeochemical cycling of elemental mercury: Anthropogenic influences, Geochim. Cosmochim. Acta, 58: 3191-3198 (2) Shia R.L., Seigneur C., Pai P., Ko M., and Sze N.-D. (1999), Global simulation of atmospheric mercury concentrations and deposition fluxes, J. Geophy. Res., 104(D19), 23, 747-23, 760 (3) Mason, R.P., Lawson N.M., and Sheu G.-R. (2001), Mercury in the Atlantic Ocean: factors controlling air-sea exchange of mercury and its distribution in the upper water, Deep-Sea Res. II, 2829-2853 (4) Lamborg, C.H., Rolfus K.R., and Fitzgerald W.F. (1999), The atmospheric cycling and air-sea exchange of mercury species in the south and equatorial Atlantic Ocean, Deep-Sea Res. II, 957-977 (5) Lindberg S.E., Brooks S., Lin C.-J., Scott K. J., Landis M. S., Stevens R.K., Goodsite M., and Richter A. (2002), Dynamic oxidation of gaseous mercury in the arctic troposphere at polar sunrise, Environ. Sci. Technol., 1245-1256 (6) Bullock O.R. (2000), Modeling assessment of transport and deposition patterns of anthropogenic mercury air emissions in the United States and Canada, Sci Total Environ., 259(1-3), 145-157 (7) Xu X., Yang X., Miller d.R., Helble J.J., and Carley R.J. (2000), a regional scale modelling study of atmospheric transport and formation of mercury. II. Simulation results for the northeast United states, Atmos. Environ., 34: 4945-4955 (8) Sheu G.-R. (2001), Speciation and distribution of atmospheric mercury: Significance of reactive gaseous mercury in the global mercury cycle. PhD. thesis, University of Maryland, College park, pp. 170 (9) Guentzel J.L., Landing W.M., Gill G.A., and Pollman C.D. (2001), Processes influencing rainfall deposition of mercury in Florida, Environ. Sci. Technol., 35: 863-873

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kokkoris, George; Boudouvis, Andreas G.; Gogolides, Evangelos

An integrated framework for the neutral flux calculation inside trenches and holes during plasma etching is described, and a comparison between the two types of structure in a number of applications is presented. First, a detailed and functional set of equations for the neutral and ion flux calculations inside long trenches and holes with cylindrical symmetry is explicitly formulated. This set is based on early works [T. S. Cale and G. B. Raupp, J. Vac. Sci. Technol. B 8, 1242 (1990); V. K. Singh et al., J. Vac. Sci. Technol. B 10, 1091 (1992)], and includes new equations for themore » case of holes with cylindrical symmetry. Second, a method for the solution of the respective numerical task, i.e., one or a set of linear or nonlinear integral equations, is described. This method includes a coupling algorithm with a surface chemistry model and resolves the singularity problem of the integral equations. Third, the fluxes inside trenches and holes are compared. The flux from reemission is the major portion of the local flux at the bottom of both types of structure. The framework is applied in SiO{sub 2} etching by fluorocarbon plasmas to predict the increased intensity of reactive ion etching lag in SiO{sub 2} holes compared to trenches. It is also applied in deep Si etching: By calculating the flux of F atoms at the bottom of very high aspect ratio (up to 150) Si trenches and holes during the gas chopping process, the aspect ratio at which the flux of F atoms is eliminated and etching practically stops is estimated.« less

Effect of frequency on the uniformity of symmetrical RF CCP discharges

NASA Astrophysics Data System (ADS)

Liu, Yue; Booth, Jean-Paul; Chabert, Pascal

2018-05-01

A 2D Cartesian electrostatic particle-in-cell/Monte Carlo collision (PIC/MCC) model presented previously (Liu et al 2018 Plasma Sources Sci. Technol. 27 025006) is used to investigate the effect of the driving frequency (over the range of 15–45 MHz) on the plasma uniformity in radio frequency (RF) capacitively coupled plasma (CCP) discharges in a geometrically symmetric reactor with a dielectric side wall in argon gas. The reactor size (12 cm electrode length, 2.5 cm gap) and driving frequency are sufficiently small that electromagnetic effects can be ignored. Previously, we showed (Liu et al 2018 Plasma Sources Sci. Technol. 27 025006) that for 15 MHz excitation, Ohmic heating of electrons by the electric field perpendicular to the electrodes is enhanced in a region in front of the dielectric side wall, leading to a maximum in electron density there. In this work we show that increasing the excitation frequency (at constant applied voltage amplitude) not only increases the overall electron heating and density but also causes a stronger, narrower peak in electron heating closer to the dielectric wall, improving the plasma uniformity along the electrodes. This heating peak comes both from enhanced perpendicular electron heating and from the appearance at high frequency of significant parallel heating. The latter is caused by the presence of a significant parallel-direction RF oscillating electric field in the corners. Whereas at the reactor center the sheaths oscillate perpendicularly to the electrodes, near the dielectric edge they move in and out of the corners and must be treated in two dimensions.

Room temperature deposition of gold onto the diffuse and sharp diffraction spot Si(111)-( 3 × 3) R30° Au surfaces

NASA Astrophysics Data System (ADS)

Plass, Richard; Marks, Laurence D.

1996-06-01

Room temperature gold depositions onto Si(111)-( 3 × 3) R30° Au surfaces with diffuse and sharp diffraction spots [Surf. Sci. 242 (1991) 73] (diffuse and sharp 3 × 3 Au hereafter) under UHV conditions has been monitored using transmission electron diffraction (TED). Both systems display an increase in surface structure diffraction spot intensities up to the completion of 1.0 monolayer (ML) after which the surface beams display an exponential decrease in intensity with coverage. The exponential decay rate decreases after roughly 1.33 ML. These results can be attributed to gold initially diffusing to and filling 3 × 3 Au gold trimer sites in vacancy type surface domain walls [Surf. Sci. 342 (1995) 233], then filling one of three possible sites on the 3 × 3 Au structure with essentially no surface diffusion, disrupting nearby gold trimers. Gold deposition onto the diffuse type structure caused the formation and expansion of satellite arcs around the strongest 3 × 3 beams similar to those seen by others [Surf. Sci. 242 (1991) 73; Jpn. J. Appl. Phys. 16 (1977) 891; J. Vac. Sci. Technol. A 10 (1992) 3486] at elevated temperatures while the sharp structure displayed only a modest shoulder formation near the strongest 3 × 3 beams.

Experimental investigation of concentration and stable isotopes signals during organic contaminants back diffusion

NASA Astrophysics Data System (ADS)

Jin, Biao; Nika, Chrysanthi-Elisabeth; Rolle, Massimo

2017-04-01

Back diffusion of organic contaminants is often the cause of groundwater plumes' persistence and can significantly hinder cleanup interventions [1, 2]. In this study we perform a high-resolution investigation of back diffusion in a well-controlled flow-through laboratory setup. We considered cis-dichloroethene (cis-DCE) as model contaminant and we investigated its back diffusion from an impermeable source into a permeable saturated layer, in which advection-dominated flow conditions were established. We used concentration and stable chlorine isotope measurements to investigate the plumes originated by cis-DCE back diffusion in a series of flow-through experiments, performed in porous media with different hydraulic conductivity and at different seepage velocities (i.e., 0.4, 0.8 and 1.2 m/day). A two-centimeter thick agarose gel layer was placed at the bottom of the setup to simulate the source of cis-DCE back diffusion from an impervious layer. Intensive sampling (>1000 measurements) was carried out, including the withdrawal of aqueous samples at closely spaced (1 cm) outlet ports, as well as the high-resolution sampling of the source zone (agarose gel) at the end of each experiment. The transient behavior of the plumes originated by back diffusion was investigated by sampling the outlet ports at regular intervals in the experiments, each run for a total time corresponding to 15 pore volumes. The high-resolution sampling allowed us to resolve the spatial and temporal evolution of concentration and stable isotope gradients in the flow-through setup. In particular, steep concentration and stable isotope gradients were observed at the outlet. Lateral isotope gradients corresponding to chlorine isotope fractionation up to 20‰ were induced by cis-DCE back diffusion and subsequent advection-dominated transport in all flow-through experiments. A numerical modeling approach, tracking individually all chlorine isotopologues, based on the accurate parameterization of local dispersion, as well as on the values of aqueous diffusion coefficients and diffusion-induced isotope fractionation from a previous study [3], provided a good agreement with the experimental data. References [1] Mackay, D. M.; Cherry, J. A. Groundwater contamination: Pumpand-treat remediation. Environ. Sci. Technol. 1989, 23, 630-636. [2] Parker, B. L.; Chapman, S. W.; Guilbeault, M. A. Plume persistence caused by back diffusion from thin clay layers in a sand aquifer following TCE source-zone hydraulic isolation. J. Contam. Hydrol. 2008, 102, 19-19. [3] Jin, B., Rolle, M., Li, T., Haderlein, S.B., 2014. Diffusive fractionation of BTEX and chlorinated ethenes in aqueous solution: quantification of spatial isotope gradients. Environ. Sci. Technol. 48, 6141-6150.

Controls on radium transport by adsorption to iron minerals

NASA Astrophysics Data System (ADS)

Chen, M.; Wang, T.; Kocar, B. D.

2015-12-01

Radium is a naturally occurring radioactive metal found in many subsurface environments. Radium isotopes are generated by uranium and thorium decay, and are particularly abundant within groundwaters where minimal porewater flux leads to accumulation. These isotopes are used as natural tracers for estimating submarine groundwater discharge (SGD) [1], allowing for large scale estimation of GW fluxes into and out of the ocean [2]. They also represent a substantial hazard in wastewater produced after hydraulic fracturing for natural gas extraction [3], resulting in a significant risk of environmental release to surface and near-surface waters, and increased cost for water treatment or disposal. Adsorption to mineral surfaces represents a dominant pathway of radium retention in subsurface environments. For SGD studies, adsorption processes impact estimates of GW fluxes, while in hydraulic fracturing, radium adsorption to aquifer solids mediates wastewater radium activities. Analysis of past sorption studies revealed large variability in partition coefficients [4], while examination of radium adsorption kinetics and surface complexation have only recently started [5]. Accordingly, we present the results of sorption and column experiments of radium with a suite of iron minerals representative of those found within deep saline and near-surface (freshwater) aquifers, and evaluate impacts of varying salinity solutions through artificial waters. Further, we explore the impacts of pyrite oxidation and ferrihydrite transformation to other iron-bearing secondary minerals on the transport and retention of radium. These results will provide critical information on the mineralogical controls on radium retention in subsurface environments, and will therefore improve predictions of radium groundwater transport in natural and contaminated systems. [1] Charette, M.A., Buesseler, K.O. & Andrews, J.E., Limnol. Oceanogr. (2001). [2] Moore, W.S., Ann. Rev. Mar. Sci. (2010). [3] Vengosh, A. et al. Environ. Sci. Technol., (2014). [4] Beck, A., Cochran, M., Marine Chem., (2013). [5] Sajih, M. et al. Geochim. Cosmochim. AC. (2014).

COLLABORATIVE RESEARCH AND DEVELOPMENT (CR&D) Delivery Order 0063: Flexible and Transparent Electronics (FAT) Development

DTIC Science & Technology

2008-02-01

Suzuki, T . Matsushita, T . Aoki and M. Okuda, Thin Solid Films, 445, p263 (2003). 7 S.M. Park, T . Ikegami , K. Ebihara and P.K. Shin, App. Surf...quality films and substrates have negligible scatter therefore we may take the absorption to be 1- T -R, where T and R are the specularly resolved...1995. 2 T . Minami, Semicond. Sci. Technol. 20, S35–S44 (2005). 3 G. Fang, D. Li and B.L. Yao, Vacuum 68, p363 (2003). 4 T . Minami, S. Suzuki and T

Variation of thermophysical parameters of PCM CaCl2.6H2O with dopant from T-history data analysis

NASA Astrophysics Data System (ADS)

Sutjahja, I. M.; Silalahi, Alfriska O.; Sukmawati, Nissa; Kurnia, D.; Wonorahardjo, S.

2018-03-01

T-history is a powerful method for deriving the thermophysical parameters of a phase change material (PCM), which consists of solid and liquid specific heats as well as latent heat enthalpy. The performance of a PCM for thermal energy storage could be altered by chemical dopants added directly to the PCM in order to form a stable suspension. We described in this paper the role of chemical dopants in the variation of thermophysical parameters for CaCl2 · 6H2O inorganic PCM with 1 wt% and 2 wt% dopant concentration and BaSO4 (1 wt%) as a nucleator using the T-history method. The dopant consists graphite and CuO nanoparticles. The data analysis follows the original method proposed by (Zhang et al 1999 Meas. Sci. Technol. 10 201–205) and its modification by (Hong et al 2004 Int. J. Refrig. 27 360–366). In addition, the enthalpy-temperature curve is obtained by adopting a method proposed by (Marín et al 2003 Meas. Sci. Technol. 14 184–189). We found that the solid specific heat tends to increase non-linearly with increased dopant concentration for all dopants. The increased liquid specific heat, however, indicates the optimum value for 1 wt% graphite dopant. In contrast, the CuO dopant shows a smaller increase in dopant concentration. The specific heat data are analyzed based on the interacting mesolayer model for a nanofluid. The heat of fusion show strong variation with dopant type, in agreement with other experimental data for various PCMs and dopant particles.

[Analysis on literatures about clinical treatment of low back pain with acupuncture and moxibustion published in the periodicals included by SCI in recent 5 years].

PubMed

Jiang, Chui-gang

2007-03-01

To explore the development state of acupuncture and moxibustion therapy in the world. Retrieve and analyze the literatures about clinically treating low back pain with acupuncture and moxibustion published at periodicals included by SCI in recent 5 years in Pubmed. Nineteen concerned literatures were retrieved. Authors of the literatures come from USA, Germany, Hong Kong of China, UK (including Northern Ireland) , Austria, Sweden and Italy. The literatures were published at Altern Ther Health Med, Am J Phys Med Rehabil, Anesth Analg, Arch Intern Med, Forsch Komplementärmed Klass Naturheilkd, Health Technol Assess, Rheumatology (Oxford), South Med J, Spine, Complment Ther Med, Pain. Three researches show that efficacy of acupuncture is uncertain. Other researches support the efficacy of acupuncture. The researches on treating low back pain with acupuncture and moxibustion are still mainly about efficacy of the acupuncture and moxibustion therapy. The acupuncture and moxibustion therapy is still in the process of gradually admitted by international medicine.

Studies of Turbulence and Transport in Alcator C-Mod H-Mode Plasmas with Phase Contrast Imaging and Comparisons with GYRO

NASA Astrophysics Data System (ADS)

Porkolab, M.; Lin, L.; Edlund, E. M.; Rost, J. C.; Fiore, C. L.; Greenwald, M.; Mikkelsen, D.

2008-11-01

We present recent experimental measurements of turbulence and transport in C-Mod H-Mode plasmas with and without internal transport barriers (ITB) using the phase contrast imaging (PCI) diagnostic and compare the results with GYRO predictions. In plasmas without ITB, the fluctuation above 300 kHz observed by PCI agrees with ITG in GYRO simulation, including the direction of propagation, wavenumber spectrum, and absolute intensity within experimental uncertainly (+/-75%). After transition to ITBs, the observed overall fluctuation intensity increases. GYRO simulation in the core shows that ITG dominates in ITBs but its intensity is lower than the overall experimental measurements which may also include contributions from the plasma edge. These results, as well as the impact of varying ∇Ti, ∇n, and ExB shear on turbulence will be discussed. C.L. Fiore et al., Fusion Sci. Technol., 51, 303 (2007). M. Porkolab et al., IEEE Trans. Plasma Sci. 34, 229 (2006). J. Candy et al., Phys. Rev. Lett., 91, 045001 (2003).

Flux Pinning Enhancement in YBa2Cu3O7-x Films with BaSnO3 Nanoparticles

DTIC Science & Technology

2008-10-01

SUPERCONDUCTOR SCIENCE AND TECHNOLOGY Supercond. Sci. Technol. 19 (2006) L37 –L41 doi:10.1088/0953-2048/19/10/L01 RAPID COMMUNICATION Flux pinning enhancement in...2006 Online at stacks.iop.org/SUST/19/ L37 Abstract Nanoparticles of BaSnO3 were incorporated into YBa2Cu3O7−x (YBCO) films on LaAlO3 substrates for...0953-2048/06/100037+05$30.00 © 2006 IOP Publishing Ltd Printed in the UK L37 1 Rapid Communication materials and sintered together to form a composite

Localized heating of electrons in ionization zones: Going beyond the Penning-Thornton paradigm in magnetron sputtering

DOE Office of Scientific and Technical Information (OSTI.GOV)

Anders, Andre

2014-12-07

The fundamental question of how energy is supplied to a magnetron discharge is commonly answered by the Penning-Thornton paradigm invoking secondary electrons. Huo et al. (Plasma Sources Sci. Technol. 22, 045005, (2013)) used a global discharge model to show that electron heating in the electric field of the magnetic presheath is dominant. In this contribution, this concept is applied locally taking into account the electric potential structure of ionization zones. Images of ionization zones can and should be interpreted as diagrams of the localization of electric potential and related electron energy, where certain collisions promote or dampen their formation.

Manufacturable Tri-Stack AlSb/InAs HEMT Low-Noise Amplifiers Using Wafer-Level-Packaging Technology for Light-Weight and Ultralow-Power Applications

DTIC Science & Technology

2009-05-01

shown in Fig. 1 was grown by molecular - beam epitaxy (MBE) on 3-inch semi-insulating GaAs substrates. AlGaSb was used as a buffer. AlSb was used as... beam epitaxy for low-power applications,” J. Vac. Sci. Technol. B. 24, pp. 2581-2585, 2006. [12] Y. C. Chou, L. J. Lee, J. M. Yang, M. D. Lange, P...passivation AlGaSb buffer Figure 1: Cross section of an AlSb/InAs HEMT device on a 3-inch GaAs substrate. The interface region between the

Temperature Dependent Spectral Response and Detectivity of GeSn Photoconductors on Silicon for Short Wave Infrared Detection

DTIC Science & Technology

2014-01-01

Littler, M. Canonico, S. Zollner, J. Kouvetakis, and J. Menéndez, "Optical critical points of thin- film Ge1−ySny alloys : A comparative Ge1−ySny∕Ge1...Bernardy, T. Stoica, D. Grützmacher, and S. Mantl, "Reduced Pressure CVD Growth of Ge and Ge1−xSnx Alloys ," ECS J. of Solid State Sci. and Technol. 2... oxide etch, 10 nm of Cr followed by 200 nm of Au was deposited for the Ohmic contacts. These contacts showed a linear I-V behavior, thus no

Molecular Simulations of the Diffusion of Uranyl Carbonate Species in Nanosized Mineral Fractures

NASA Astrophysics Data System (ADS)

Kerisit, S.; Liu, C.

2010-12-01

Uranium is a major groundwater contaminant at uranium processing and mining sites as a result of intentional and accidental discharges of uranium-containing waste products into subsurface environments. Recent characterization has shown that uranium preferentially associates with intragrain and intra-aggregate domains in some of the uranium-contaminated sediments collected from the US Department of Energy Hanford Site [1, 2]. In these sediments, uranium existed as precipitated and/or adsorbed phases in grain micropores with nano- to microscale sizes. Desorption and diffusion characterization studies and continuum-scale modeling indicated that ion diffusion in the microfractures is a major mechanism that led to preferential uranium concentration in the microfracture regions and will control the future mobility of uranium in the subsurface sediments [1, 3-4]. However, the diffusion properties of uranyl species in the intragrain regions, especially at the solid-liquid interface, are still poorly understood. Therefore, a general aim of this work is to provide atomic-level insights into the contribution of microscopic surface effects to the slow diffusion process of uranyl species in porous media with nano- to microsized fractures. In this presentation, we will first present molecular dynamics (MD) simulations of feldspar-water interfaces to investigate their interfacial structure and dynamics and establish a theoretical framework for subsequent simulations of water and ion diffusion at these interfaces [5]. We will then report on MD simulations carried out to probe the effects of confinement and of the presence of the mineral surface on the diffusion of water and electrolyte ions in nanosized feldspar fractures [6]. Several properties of the mineral-water interface were varied, such as the fracture width, the ionic strength of the contacting solution, and the surface charge. Our calculations reveal a 2.0-2.5 nm interfacial region within which the diffusion properties of water and that of the electrolyte ions differ significantly from those in bulk aqueous solutions. We will then present MD simulations of the diffusion of a series of alkaline-earth uranyl carbonate species in aqueous solutions [7]. The MD simulations show that the alkaline-earth uranyl carbonate complexes have distinct water exchange dynamics, which could lead to different reactivities. Finally, we will present recent results on the diffusion and adsorption of uranyl carbonate species in intragrain micropores, modeled with the feldspar-water interfaces mentioned in the above, to help interpret the diffusion behavior of uranium in contaminated sediments. [1] Liu C. et al. Geochim. Cosmochim. Acta 68 4519 (2004) [2] McKinley J. P. et al. Geochim. Cosmochim. Acta 70 1873 (2006) [3] Liu C. et al. Water Resour. Res. 42 W12420 (2006) [4] Ilton E. S. et al. Environ. Sci. Technol. 42 1565 (2009) [5] Kerisit S. et al. Geochim. Cosmochim. Acta 72 1481 (2008) [6] Kerisit S. and Liu C. Environ. Sci. Technol. 43 777 (2009) [7] Kerisit S. and Liu C. Geochim. Cosmochim. Acta 74 4937 (2010)

3D-calibration of three- and four-sensor hot-film probes based on collocated sonic using neural networks

NASA Astrophysics Data System (ADS)

Kit, Eliezer; Liberzon, Dan

2016-09-01

High resolution measurements of turbulence in the atmospheric boundary layer (ABL) are critical to the understanding of physical processes and parameterization of important quantities, such as the turbulent kinetic energy dissipation. Low spatio-temporal resolution of standard atmospheric instruments, sonic anemometers and LIDARs, limits their suitability for fine-scale measurements of ABL. The use of miniature hot-films is an alternative technique, although such probes require frequent calibration, which is logistically untenable in field setups. Accurate and truthful calibration is crucial for the multi-hot-films applications in atmospheric studies, because the ability to conduct calibration in situ ultimately determines the turbulence measurements quality. Kit et al (2010 J. Atmos. Ocean. Technol. 27 23-41) described a novel methodology for calibration of hot-film probes using a collocated sonic anemometer combined with a neural network (NN) approach. An important step in the algorithm is the generation of a calibration set for NN training by an appropriate low-pass filtering of the high resolution voltages, measured by the hot-film-sensors and low resolution velocities acquired by the sonic. In Kit et al (2010 J. Atmos. Ocean. Technol. 27 23-41), Kit and Grits (2011 J. Atmos. Ocean. Technol. 28 104-10) and Vitkin et al (2014 Meas. Sci. Technol. 25 75801), the authors reported on successful use of this approach for in situ calibration, but also on the method’s limitations and restricted range of applicability. In their earlier work, a jet facility and a probe, comprised of two orthogonal x-hot-films, were used for calibration and for full dataset generation. In the current work, a comprehensive laboratory study of 3D-calibration of two multi-hot-film probes (triple- and four-sensor) using a grid flow was conducted. The probes were embedded in a collocated sonic, and their relative pitch and yaw orientation to the mean flow was changed by means of motorized traverses. The study demonstrated that NN-calibration is a powerful tool for calibration of multi-sensor 3D-hot film probes embedded in a collocated sonic, and can be employed in long-lasting field campaigns.

EDITORIAL: Outgoing Editor-in-Chief Outgoing Editor-in-Chief

NASA Astrophysics Data System (ADS)

Hauptmann, Peter

2012-01-01

I started in 2002 as Editor-in-Chief of a well established journal—MST (Measurement Science and Technology). It was a time when modern means of communication offered new opportunities for the scientific community—for all scientists and engineers whether at universities, in industry or at other institutions—to access better quality information in a shorter time. This development helped us to be more efficient in our daily scientific work and to anticipate new trends faster than before. A flood of information was created by different search engines. A few online journals or journals published in emerging countries with a similar profile to MST appeared on the market. MST had to provide new answers in response to these developments. In 2002 I postulated two requirements to the journal. Firstly, the publisher has to be up to date. My impression over the years has been that IOPP is excellently organized. That has made it easier for the board members and all our reviewers to concentrate on the scientific aspects of our input to the journal. During all my visits to Bristol or my contacts with the IOPP staff I always met very professional and enthusiastic staff members. They have not only supported and encouraged the ideas and initiatives of the Editorial Board members, but they have also worked hard on establishing one of the most effective journal operations in the field of measurement science and technology. Many authors are well aware of this. Thus I am able to declare that the first requirement for a successful journal has been met. Secondly, the scientific level has to be high and the journal should attract readers from all over the world. This task was the responsibility of the Editorial Board members and of myself. Our strategy was on the one hand to ensure continuity in MST but on the other hand to be open to new trends and developments. Examples of these new aspects of the journal are fields like micro- and nanometrology, measurement techniques for biological, medical and life science applications or sensors and sensing systems. Selected papers or special features in recent issues of MST attest to this development [1-3]. In parallel with these new fields, board members have always kept their eye on the other journal topics. Many papers published in MST have been downloaded very often and highly cited. This shows the acceptance and reputation of MST. Thanks to the activity of all board members over the last ten years MST has published a number of excellent review articles. This has strengthened the prestige of MST. A new series of articles was introduced under the banner of 'Perspectives' in 2008. They highlight milestones in a selected field and indicate some future challenges from the point of view of the author [4]. In summary, it can be stated that MST is on a good path. This was created thanks to the activity of all members of the Editorial Board. In recent years we have enlarged this board with well known scientists from universities and industry from all over the world. This will ensure a continuously positive development of MST. As outgoing Editor-in-Chief, I can say that I have found my task fascinating and I have enjoyed it very much. I have learned a lot in this time because I have come into close contact with a large number of scientists from a vast spectrum of technical areas and parts of our world. My special gratitude is dedicated to all the Editorial Board members of the last ten years and especially to Sharon D'Souza from IOPP. Furthermore, I would like to pass on to my successor, Professor David Birch from University of Strathclyde, Glasgow, my best wishes for an enjoyable and successful tenure as Editor-in-Chief! References [1] Tanaka M, Baba T and Postek M T 2011 Nanometrology Meas. Sci. Technol. 22 020101 [2] Potyrailo R A et al 2011 RFID sensors as the common sensing platform for single-use biopharmaceutical manufacturing Meas. Sci. Technol. 22 082001 [3] Fritze H 2011 High-temperature bulk acoustic wave sensors Meas. Sci. Technol. 22 012002 [4] Birch D J S 2011 Fluorescence detections and directions Meas. Sci. Technol. 22 052002

Determination of the composition of HgCdTe oxide films by neutron activation analysis

NASA Astrophysics Data System (ADS)

Gnade, B.; Simmons, A.; Little, D.; Strong, R.

1987-04-01

The composition of HgCdTe oxides grown by anodic oxidation in a standard KOH/ethylene glycol solution has been determined by neutron activation analysis (NAA). This technique is not hindered by the difficulties normally associated with methods using ion beams or electron beams. Neutron activation analysis has the advantage of being quantitative, and also NAA is not affected by the chemical composition of the matrix. The analysis of the KOH/ethylene glycol oxide film by neutron activation yields Hg:Cd:Te ratios of 0.534:0.19:1, in close agreement with Rutherford backscattering spectroscopy analysis (R.L. Strong et al., J. Vac. Sci. Technol. A4 (4) (1986) 1992).

Heterogeneous freezing of droplets with immersed surface modified mineral dust particles

NASA Astrophysics Data System (ADS)

Hartmann, Susan

2010-05-01

In the framework of the international measurement campaign FROST II (FReezing Of duST), the heterogeneous freezing of droplets with an immersed surface modified size-segregated mineral dust particles was investigated at LACIS (Leipzig Aerosol Cloud Interaction Simulator, Stratmann et al. 2004). The following measurements were done: LACIS, CFDC (Continuous Flow thermal gradient Diffusion Chamber, Rogers (1988)) and FINCH (Fast Ice Nucleus Chamber Counter, Bundke et al (2008)) were used to analyze the immersion freezing behavior of the treated Arizona Test Dust (ATD) particles at different temperature regimes. The ability to act as IN (Ice Nucleus) in the deposition nucleation mode was quantified by the PINC (Portable Ice Nucleation Chamber) and the CFDC instrument. AMS (Aerosol Mass Spectrometers, e.g. Schneider et al. (2005)) and ATOFMS (Aerosol Time-Of-Flight Mass Spectrometer) measurements were applied to determine particle composition. The hygroscopic growth and the critical super-saturations needed for droplet activation were determined by means of an H-TDMA (Humidity-Tandem Differential Mobility Analyzer) and CCN counter (Cloud Condensation Nucleus counter, Droplet Measurement Technologies, Roberts and Nenes (2005)). The 300 nm ATD particles were chemically and physically treated by coating with sulphuric acid (H2SO4, three different coating thicknesses) and ammonium sulphate ((NH4)2SO4) or by thermal treatment with a thermodenuder operating at 250°C. The H2SO4 coating modified the particles by reacting with particle material, forming soluble sulfates and therefore changing surface properties. AMS showed free H2SO4 only for thick H2SO4 coatings. In the heated section of the thermodenuder coating materials were evaporated partly and the surface properties of the particles were additionally altered. Uncoated particles and those coated with thin coatings of H2SO4, showed almost no hygroscopic growth. Particles coated with thicker coatings of H2SO4 and of (NH4)2SO4 grew noticeably above 95% relative humidity. All investigated particles were found to activate at atmospherically relevant super-saturations. All kinds of treatment lower the IN-ability, whereas the deposition nucleation was more sensitive to treatments than the immersion freezing mode. Considering the immersion freezing behavior, pure ATD particles and particles coated with thin coatings of H2SO4 were more efficient IN, than particles with thick H2SO4 or (NH4)2SO4 coatings. Thermal treatments of the particles led to further decrease of the IN capability except for particles coated with (NH4)2SO4, where the heating did not effect the immersion freezing behavior likely due to their already reduced IN ability. In order to specify the temperature-dependent immersion freezing, two parameterization based on either stochastic or singular hypothesis were performed. From both theoretical approaches it can be concluded that the treatments lead to particle surface modifications lowering the nucleation efficiency. References: Bundke, U., B. Nillius, et al. (2008), The fast Ice Nucleus chamber FINCH, Atmospheric Research 90(2-4): 180-186. Rader, D. J. and P. H. McMurry (1986), Application of the Tandem Differential Mobility Analyzer to studies of droplet growth or evaporation, J. Aerosol Sci., Vol. 17, No. 5, pp. 771-787. Roberts, G., and A. Nenes (2005), A continuous-flow streamwise thermal-gradient CCN chamber for atmospheric measurements, Aerosol Sci. Technol., 39, 206-221. Schneider, J., N. Hock, S. Weimer, S. Borrmann, U. Kirchner, R. Vogt, and V. Scheer (2005), Nucleation particles in Diesel exhaust: Composition inferred from in situ mass spectrometric analysis, Environ. Sci. Technol., 39, 6153-6161. Rogers,D .C. (1988), Developmenot f a continuousflow thermal gradient diffusion chamber for ice nucleation studies. Atmospheric Research, 22, 149-181. Stratmann, F., A. Kiselev, S. Wurzler, M. Wendisch, J. Heintzenberg, R. J. Charlson, K. Diehl, H. Wex, and S. Schmidt (2004), Laboratory studies and numerical simulations of cloud droplet formation under realistic super-saturation conditions, J. Atmos. Oceanic Technol., 21, 876-887.

Integration of snow management practices into a detailed snow pack model

NASA Astrophysics Data System (ADS)

Spandre, Pierre; Morin, Samuel; Lafaysse, Matthieu; Lejeune, Yves; François, Hugues; George-Marcelpoil, Emmanuelle

2016-04-01

The management of snow on ski slopes is a key socio-economic and environmental issue in mountain regions. Indeed the winter sports industry has become a very competitive global market although this economy remains particularly sensitive to weather and snow conditions. The understanding and implementation of snow management in detailed snowpack models is a major step towards a more realistic assessment of the evolution of snow conditions in ski resorts concerning past, present and future climate conditions. Here we describe in a detailed manner the integration of snow management processes (grooming, snowmaking) into the snowpack model Crocus (Spandre et al., Cold Reg. Sci. Technol., in press). The effect of the tiller is explicitly taken into account and its effects on snow properties (density, snow microstructure) are simulated in addition to the compaction induced by the weight of the grooming machine. The production of snow in Crocus is carried out with respect to specific rules and current meteorological conditions. Model configurations and results are described in detail through sensitivity tests of the model of all parameters related to snow management processes. In-situ observations were carried out in four resorts in the French Alps during the 2014-2015 winter season considering for each resort natural, groomed only and groomed plus snowmaking conditions. The model provides realistic simulations of the snowpack properties with respect to these observations. The main uncertainty pertains to the efficiency of the snowmaking process. The observed ratio between the mass of machine-made snow on ski slopes and the water mass used for production was found to be lower than was expected from the literature, in every resort. The model now referred to as "Crocus-Resort" has been proven to provide realistic simulations of snow conditions on ski slopes and may be used for further investigations. Spandre, P., S. Morin, M. Lafaysse, Y. Lejeune, H. François and E. George-Marcelpoil, Integration of snow management processes into a detailed snowpack model, Cold Reg. Sci. Technol., in press.

Life cycle assessment of automobile/fuel options.

PubMed

MacLean, Heather L; Lave, Lester B

2003-12-01

We examine the possibilities for a "greener" car that would use less material and fuel, be less polluting, and would have a well-managed end-of-life. Light-duty vehicles are fundamental to our economy and will continue to be for the indefinite future. Any redesign to make these vehicles greener requires consumer acceptance. Consumer desires for large, powerful vehicles have been the major stumbling block in achieving a "green car". The other major barrier is inherent contradictions among social goals such as fuel economy, safety, low emissions of pollutants, and low emissions of greenhouse gases, which has led to conflicting regulations such as emissions regulations blocking sales of direct injection diesels in California, which would save fuel. In evaluating fuel/vehicle options with the potential to improve the greenness of cars [diesel (direct injection) and ethanol in internal combustion engines, battery-powered, gasoline hybrid electric, and hydrogen fuel cells], we find no option dominates the others on all dimensions. The principles of green design developed by Anastas and Zimmerman (Environ. Sci. Technol. 2003, 37, 94A-101A) and the use of a life cycle approach provide insights on the key sustainability issues associated with the various options.

Impact of Propene on Secondary Organic Aerosol Formation from m-Xylene

DOE Office of Scientific and Technical Information (OSTI.GOV)

Song, Chen; Na, Kwangsam; Warren, Bethany

2007-10-15

Propene is widely used in smog chamber experiments to increase the hydroxyl radical (OH) level based on the assumption that the formation of secondary organic aerosol (SOA) from parent hydrocarbon is unaffected. A series ofm-xylene/NOx photooxidation experiments were conducted in the presence of propene in the University of California CECERT atmospheric chamber facility. The experimental data are compared with previousm-xylene/NOx photooxidation work performed in the same chamber facility in the absence of propene (Song et al. Environ. Sci. Technol. 2005, 39, 3143-3149). The result shows that, for similar initial conditions, experiments with propene have lower reaction rates of m-xylene thanmore » those without propene, which indicates that propene reduces OH in the system. Furthermore, experiments with propene showed more than 15% reduction in SOA yield compared to experiments in the absence of propene. Additional experiments ofm-xylene/NOx with CO showed similar trends of suppressing OH and SOA formation. These results indicate that SOA from m-xylene/NOx photooxidation is strongly dependent on the OH level present, which provides evidence for the critical role of OH in SOA formation from aromatic hydrocarbons.« less

EDITORIAL: Letter from the Editor Letter from the Editor

NASA Astrophysics Data System (ADS)

Hauptmann, Peter

2011-01-01

Dear authors and reviewers of articles for Measurement Science and Technology, I would like to thank all those who have published papers with us in 2010, and special thanks go to those of you who have kindly reviewed articles for the journal. I would also like to take this opportunity to update you on some of the developments on the journal and look ahead to 2011. As many of you are no doubt aware, our impact factor (a measure of the average number of times recent papers are referred to by others) is currently 1.317. This is often taken as an indication of the quality and relevance of recently published research, and although as readers we develop our own instinct for journals of high quality, it is gratifying as an Editor to see the data from an independent organization (Thomson ISI) agreeing with my own assessment. Measurement Science and Technology is a journal with a broad scope covering new measurement techniques in all fields of science and engineering. I therefore find it particularly enjoyable to read summaries of recent research in our strong topical review programme as these cover many varied topics of interest. In 2010 several interesting articles by international leaders in their field were published, for example: Single-photon generation and detection, by G S Buller and R J Collins of Heriot-Watt University [1]. Fluorescence lifetime imaging microscopy in life sciences, by Jan Willem Borst and Antonie J W G Visser, from the Microspectroscopy Centre of Wageningen University [2]. Biological and chemical sensors for cancer diagnosis, by Elfriede Simon of Siemens AG [3]. I hope that these articles, and the others published in 2010 and now in 2011, will provide a useful overview for our readers, and be helpful to new researchers. When speaking to young researchers I am particularly aware that having their articles published in a timely fashion is important, and I am pleased that our publication times are highly competitive, with most authors receiving a publication decision within 7 weeks and most articles being published a month after acceptance. Looking forward to 2011, we will continue to rely on you, our esteemed reviewers, for your help in determining which articles make a significant contribution to the field of measurements. Your work is highly valued, not only by those of us who work directly on the journal, but also by the readers who can continue to refer to MST knowing that only work of a high standard is published here. There simply remains for me to say thank you again for your contribution to Measurement Science and Technology in 2010, and I wish you all the best for a successful 2011! References [1] Buller G S and Collins R J 2010 Single-photon generation and detection Meas. Sci. Technol. 21 012002 [2] Borst J W and Visser A J W G 2010 Fluorescence lifetime imaging microscopy in life sciences Meas. Sci. Technol. 21 102002 [3] Simon E 2010 Biological and chemical sensors for cancer diagnosis Meas. Sci. Technol. 21 112002

Industrial applications using BASF eco-efficiency analysis: perspectives on green engineering principles.

PubMed

Shonnard, David R; Kicherer, Andreas; Saling, Peter

2003-12-01

Life without chemicals would be inconceivable, but the potential risks and impacts to the environment associated with chemical production and chemical products are viewed critically. Eco-efficiency analysis considers the economic and life cycle environmental effects of a product or process, giving these equal weighting. The major elements of the environmental assessment include primary energy use, raw materials utilization, emissions to all media, toxicity, safety risk, and land use. The relevance of each environmental category and also for the economic versus the environmental impacts is evaluated using national emissions and economic data. The eco-efficiency analysis method of BASF is briefly presented, and results from three applications to chemical processes and products are summarized. Through these applications, the eco-efficiency analyses mostly confirm the 12 Principles listed in Anastas and Zimmerman (Environ. Sci. Technol. 2003, 37(5), 94A), with the exception that, in one application, production systems based on bio-based feedstocks were not the most eco-efficient as compared to those based on fossil resources. Over 180 eco-efficiency analyses have been conducted at BASF, and their results have been used to support strategic decision-making, marketing, research and development, and communication with external parties. Eco-efficiency analysis, as one important strategy and success factor in sustainable development, will continue to be a very strong operational tool at BASF.

Metal mobilization by iron- and sulfur-oxidizing bacteria in a multiple extreme mine tailings in the Atacama Desert, Chile.

PubMed

Korehi, H; Blöthe, M; Sitnikova, M A; Dold, B; Schippers, A

2013-03-05

The marine shore sulfidic mine tailings dump at the Chañaral Bay in the Atacama Desert, northern Chile, is characterized by extreme acidity, high salinity, and high heavy metals concentrations. Due to pyrite oxidation, metals (especially copper) are mobilized under acidic conditions and transported toward the tailings surface and precipitate as secondary minerals (Dold, Environ. Sci. Technol. 2006, 40, 752-758.). Depth profiles of total cell counts in this almost organic-carbon free multiple extreme environment showed variable numbers with up to 10(8) cells g(-1) dry weight for 50 samples at four sites. Real-time PCR quantification and bacterial 16S rRNA gene diversity analysis via clone libraries revealed a dominance of Bacteria over Archaea and the frequent occurrence of the acidophilic iron(II)- and sulfur-oxidizing and iron(III)-reducing genera Acidithiobacillus, Alicyclobacillus, and Sulfobacillus. Acidophilic chemolithoautotrophic iron(II)-oxidizing bacteria were also frequently found via most-probable-number (MPN) cultivation. Halotolerant iron(II)-oxidizers in enrichment cultures were active at NaCl concentrations up to 1 M. Maximal microcalorimetrically determined pyrite oxidation rates coincided with maxima of the pyrite content, total cell counts, and MPN of iron(II)-oxidizers. These findings indicate that microbial pyrite oxidation and metal mobilization preferentially occur in distinct tailings layers at high salinity. Microorganisms for biomining with seawater salt concentrations obviously exist in nature.

Fast Fourier transform-based solution of 2D and 3D magnetization problems in type-II superconductivity

NASA Astrophysics Data System (ADS)

Prigozhin, Leonid; Sokolovsky, Vladimir

2018-05-01

We consider the fast Fourier transform (FFT) based numerical method for thin film magnetization problems (Vestgården and Johansen 2012 Supercond. Sci. Technol. 25 104001), compare it with the finite element methods, and evaluate its accuracy. Proposed modifications of this method implementation ensure stable convergence of iterations and enhance its efficiency. A new method, also based on the FFT, is developed for 3D bulk magnetization problems. This method is based on a magnetic field formulation, different from the popular h-formulation of eddy current problems typically employed with the edge finite elements. The method is simple, easy to implement, and can be used with a general current–voltage relation; its efficiency is illustrated by numerical simulations.

Radium Adsorption to Iron Bearing Minerals in Variable Salinity Waters

NASA Astrophysics Data System (ADS)

Chen, M.; Kocar, B. D.

2014-12-01

Radium is a common, naturally occurring radioactive metal found in many subsurface environments. Radium isotopes are a product of natural uranium and thorium decay, and are particularly abundant within groundwaters where minimal flux leads to accumulation within porewaters. Radium has been used as a natural tracer to estimate submarine groundwater discharge (SGD) [1], where the ratios of various radium isotopes are used to estimate total groundwater flux to and from the ocean [2]. Further, it represents a substantial hazard in waste water produced after hydraulic fracturing for natural gas extraction [3], resulting in a significant risk of environmental release and increased cost for water treatment or disposal. Adsorption to mineral surfaces represents a primary pathway of radium retention within subsurface environments. For SGD studies, it is important to understand adsorption processes to correctly estimate GW fluxes, while in hydraulic fracturing, radium adsorption to aquifer solids will mediate the activities of radium within produced water. While some studies of radium adsorption to various minerals have been performed [4], there is a limited understanding of the surface chemistry of radium adsorption, particularly to iron-bearing minerals such as pyrite, goethite and ferrihydrite. Accordingly, we present the results of sorption experiments of radium to a suite of iron-bearing minerals representative of those found within deep saline and near-surface (freshwater) aquifers, and evaluate impacts of varying salinity solutions through the use of artificial groundwater, seawater, and shale formation brine. Further, we explore the impacts of pyrite oxidation and ferrihydrite transformation to other iron-bearing secondary minerals on the retention of radium. This work lays the groundwork for further study of radium use as a tracer for SGD, as well as understanding mechanisms of radium retention and release from deep aquifer materials following hydraulic fracturing operations. [1] Charette, M.A., Buesseler, K.O. & Andrews, J.E., Limnol. Oceanogr. 46, 465-470 (2001). [2] Moore, W.S., Ann. Rev. Mar. Sci. 2, 59-88 (2010). [3] Vengosh, A., Jackson, R.B., Warner, N., Darrah, T.H. & Kondash, Environ. Sci. Technol., (2014). [4] Ames, L.L, McGarrah, J., & Walker, B., Clays Clay Miner. 31, 335-342 (1983).

Reactions of SIV species with organic compounds: formation mechanisms of organo-sulfur derivatives in atmospheric aerosols

NASA Astrophysics Data System (ADS)

Passananti, Monica; Shang, Jing; Dupart, Yoan; Perrier, Sébastien; George, Christian

2015-04-01

Secondary organic aerosol (SOA) have an important impact on climate, air quality and human health. However the chemical reactions involved in their formation and growth are not fully understood or well-constrained in climate models. It is well known that inorganic sulfur (mainly in oxidation states (+IV) and (+VI)) plays a key role in aerosol formation, for instance sulfuric acid is known to be a good nucleating gas. In addition, acid-catalyzed heterogeneous reactions of organic compounds has shown to produce new particles, with a clear enhancement in the presence of ozone (Iinuma 2013). Organosulfates have been detected in tropospheric particles and aqueous phases, which suggests they are products of secondary organic aerosol formation process (Tolocka 2012). Originally, the production of organosulfates was explained by the esterification reaction of alcohols, but this reaction in atmosphere is kinetically negligible. Other formation pathways have been suggested such as hydrolysis of peroxides and reaction of organic matter with sulfite and sulfate radical anions (SO3-, SO4-) (Nozière 2010), but it remains unclear if these can completely explain atmospheric organo-sulfur aerosol loading. To better understand the formation of organo-sulfur compounds, we started to investigate the reactivity of SIV species (SO2 and SO32-) with respect to specific functional groups (organic acids and double bonds) on atmospherically relevant carboxylic acids and alkenes. The experiments were carried out in the homogeneous aqueous phase and at the solid-gas interface. A custom built coated-wall flow tube reactor was developed to control relativity humidity, SO2 concentration, temperature and gas flow rate. Homogeneous and heterogeneous reaction kinetics were measured and resulting products were identified using liquid chromatography coupled with an orbitrap mass spectrometer (LC-HR-MS). The experiments were performed with and without the presence of ozone in order to evaluate any impact on the SIV oxidation and product formation. Preliminary results reveal that oxidation of SIV species can occur under a variety of atmospherically relevant conditions. Furthermore, LC-HR-MS analysis confirms the formation of organo-sulfur compounds that could derive from sulfate and/or the sulfite radical anion. These results elucidate the role of organo-sulfates aqueous and interfacial chemistry, important for our scientific understanding of atmospheric SOA formation. Iinuma Y., Kahnt A., Mutzel A., Böge O., Herrmann H., Environ. Sci. Technol., 2013, (47), 3639-3647, DOI: 10.1021/es305156z. Mauldin III R. L., Berndt T., Sipilä M., Paasonen P., Petäjä T., Kim S., Kurtén T., Stratmann F., Kerminen V.-M., Kulmala M., Nature, 2012, (488), 193-196, DOI: 10.1038/nature11278. Nozière B., Ekström S., AlsbergT., Holmström S., Geophys. Res. Lett., 2010, (37), 1-6, DOI: 10.1029/2009GL041683. Tolocka M.P., Turpin B., Environ. Sci. Technol., 2012, (46), 7978-7983, DOI: 10.1021/es300651v.

New Insight into the Local Structure of Hydrous Ferric Arsenate Using Full-Potential Multiple Scattering Analysis, Density Functional Theory Calculations, and Vibrational Spectroscopy.

PubMed

Wang, Shaofeng; Ma, Xu; Zhang, Guoqing; Jia, Yongfeng; Hatada, Keisuke

2016-11-15

Hydrous ferric arsenate (HFA) is an important arsenic-bearing precipitate in the mining-impacted environment and hydrometallurgical tailings. However, there is no agreement on its local atomic structure. The local structure of HFA was reprobed by employing a full-potential multiple scattering (FPMS) analysis, density functional theory (DFT) calculations, and vibrational spectroscopy. The FPMS simulations indicated that the coordination number of the As-Fe, Fe-As, or both in HFA was approximately two. The DFT calculations constructed a structure of HFA with the formula of Fe(HAsO 4 ) x (H 2 AsO 4 ) 1-x (OH) y ·zH 2 O. The presence of protonated arsenate in HFA was also evidenced by vibrational spectroscopy. The As and Fe K-edge X-ray absorption near-edge structure spectra of HFA were accurately reproduced by FPMS simulations using the chain structure, which was also a reasonable model for extended X-Ray absorption fine structure fitting. The FPMS refinements indicated that the interatomic Fe-Fe distance was approximately 5.2 Å, consistent with that obtained by Mikutta et al. (Environ. Sci. Technol. 2013, 47 (7), 3122-3131) using wavelet analysis. All of the results suggested that HFA was more likely to occur as a chain with AsO 4 tetrahedra and FeO 6 octahedra connecting alternately in an isolated bidentate-type fashion. This finding is of significance for understanding the fate of arsenic and the formation of ferric arsenate minerals in an acidic environment.

Approximating the nonlinear density dependence of electron transport coefficients and scattering rates across the gas-liquid interface

NASA Astrophysics Data System (ADS)

Garland, N. A.; Boyle, G. J.; Cocks, D. G.; White, R. D.

2018-02-01

This study reviews the neutral density dependence of electron transport in gases and liquids and develops a method to determine the nonlinear medium density dependence of electron transport coefficients and scattering rates required for modeling transport in the vicinity of gas-liquid interfaces. The method has its foundations in Blanc’s law for gas-mixtures and adapts the theory of Garland et al (2017 Plasma Sources Sci. Technol. 26) to extract electron transport data across the gas-liquid transition region using known data from the gas and liquid phases only. The method is systematically benchmarked against multi-term Boltzmann equation solutions for Percus-Yevick model liquids. Application to atomic liquids highlights the utility and accuracy of the derived method.

The electron-phonon interaction with forward scattering peak is dominant in high T c superconductors of FeSe films on {{\\rm{SrTiO}}}_{3} (TiO2)

NASA Astrophysics Data System (ADS)

Kulić, M. L.; Dolgov, O. V.

2017-01-01

The theory of the electron-phonon interaction (EPI) with strong forward scattering peak (FSP) in an extreme delta-peak limit (Kulić and Zeyher 1994 Phys. Rev. B 49 4395; Kulić 2000 Phys. Rep. 38 1-264 Kulić and Dolgov 2005 Phys. Status Solidi b 242 151; Danylenko et al 1999 Eur. Phys. J. B 9 201) is recently applied in (Lee et al 2014 Nature 515 245; Rademaker et al 2016 New J. Phys. 18 022001; Wang et al 2016 Supercond. Sci. Technol. 29 054009) for the explanation of high {T}{{c}}(˜ 100 {{K}}) in a monolayer FeSe grown on {{{SrTiO}}}3 (Lee et al 2014 Nature 515 245) and TiO2 (Rebec et al 2016 arXiv:1606.09358v1) substrates. The EPI is due to a long-range dipolar electric field created by high-energy oxygen vibrations ({{Ω }}˜ 90 meV) at the interface (Lee et al 2014 Nature 515 245; Rademaker et al 2016 New J. Phys. 18 022001; Wang et al 2016 Supercond. Sci. Technol. 29 054009). In leading order (with respect to {T}{{c}0}/{{Ω }}) the mean-field critical temperature {T}{{c}0}={< {V}{{epi}}(q)> }q/4) ˜ {({{aq}}{{c}})}2{V}{{epi}}(0) and the gap {{{Δ }}}0=2{T}{{c}0\\text{}} are due to an interplay between the maximal EPI pairing potential {V}{{epi}}(0) and the FSP-width q c. For {T}{{c}0}˜ 100 K one has {{{Δ }}}0˜ 16 meV in a satisfactory agreement with ARPES experiments. In leading order T c0 is mass-independent and a very small oxygen isotope effect is expected in next to leading order. In clean systems T c0 for s-wave and d-wave pairing is degenerate but both are affected by non-magnetic impurities, which are pair-weakening in the s-channel and pair-breaking in the d-channel. The self-energy and replica bands at T = 0 and at the Fermi surface are calculated and compared with experimental results at T> 0 ( Rademaker et al 2016 New J. Phys. 18 022001; Wang et al 2016 Supercond. Sci. Technol. 29 054009). The EPI coupling constant {λ }{{m}}={< {V}{{epi}}(q)> }q/2{{Ω }} is mass-dependent ({M}1/2) and at ω (\\ll {{Ω }}) makes the slope of the self-energy {{Σ }}(k,ω )(≈ -{λ }{{m}}ω ) and the replica intensities {A}i(˜ {λ }{{m}}) mass-dependent. This result, overlooked in the literature, is contrary to the prediction of the standard Migdal-Eliashberg theory for EPI. The small oxygen isotope effect in {T}{{c}0} and pronounced isotope effect in {{Σ }}(k,ω ) and ARPES spectra A i of the replica bands in FeSe films on SrTiO3 and TiO2 is a smoking-gun experiment for validity of the EPI-FSP theory to these systems. The EPI-FSP theory predicts a large number of low-laying pairing states, thus causing internal pair fluctuations. The latter reduce T c0 additionally, by creating a pseudogap state for {T}{{c}}< T< {T}{{c}0}. Possibilities to increase T c0, by designing novel structures are discussed in the framework of the EPI-FSP theory.

Digital particle image thermometry/velocimetry: a review

NASA Astrophysics Data System (ADS)

Dabiri, Dana

2009-02-01

Digital particle image thermometry/velocimetry (DPIT/V) is a relatively new methodology that allows for measurements of simultaneous temperature and velocity within a two-dimensional domain, using thermochromic liquid crystal tracer particles as the temperature and velocity sensors. Extensive research has been carried out over recent years that have allowed the methodology and its implementation to grow and evolve. While there have been several reviews on the topic of liquid crystal thermometry (Moffat in Exp Therm Fluid Sci 3:14-32, 1990; Baughn in Int J Heat Fluid Flow 16:365-375, 1995; Roberts and East in J Spacecr Rockets 33:761-768, 1996; Wozniak et al. in Appl Sci Res 56:145-156, 1996; Behle et al. in Appl Sci Res 56:113-143, 1996; Stasiek in Heat Mass Transf 33:27-39, 1997; Stasiek and Kowalewski in Opto Electron Rev 10:1-10, 2002; Stasiek et al. in Opt Laser Technol 38:243-256, 2006; Smith et al. in Exp Fluids 30:190-201, 2001; Kowalewski et al. in Springer handbook of experimental fluid mechanics, 1st edn. Springer, Berlin, pp 487-561, 2007), the focus of the present review is to provide a relevant discussion of liquid crystals pertinent to DPIT/V. This includes a background on liquid crystals and color theory, a discussion of experimental setup parameters, a description of the methodology’s most recent advances and processing methods affecting temperature measurements, and finally an explanation of its various implementations and applications.

Modeling the local biodiversity impacts of agricultural water use: case study of a wetland in the coastal arid area of Peru.

PubMed

Verones, Francesca; Bartl, Karin; Pfister, Stephan; Jiménez Vílchez, Ricardo; Hellweg, Stefanie

2012-05-01

Global water use is dominated by agriculture and has considerable influence on people's livelihood and ecosystems, especially in semiarid and arid regions. Methods to address the impacts of water withdrawal and consumption on terrestrial and aquatic ecosystems within life cycle assessment are still sparse and very generic. Regionalized characterization factors (CFs) for a groundwater-fed wetland at the arid coast of Peru are developed for groundwater and surface water withdrawal and consumption in order to address the spatial dependency of water use related impacts. Several agricultural scenarios for 2020 were developed in a workshop with local stakeholders and used for calculating total biodiversity impacts. In contrast to assumptions used in top-down approaches (e.g., Pfister et al. Environ. Sci Technol. 2009, 43, 4098 ), irrigation with surface water leads in this specific region to benefits for the groundwater-fed wetland, due to additional groundwater recharge from surplus irrigation water. However, irrigation with groundwater leads to ecological damage to the wetland. The CFs derived from the different scenarios are similar and can thus be used as general CFs for this region, helping local decision-makers to plan future agricultural development, including irrigation technologies, crop choices, and protection of the wetland. © 2012 American Chemical Society

U(VI) bioreduction with emulsified vegetable oil as the electron donor--model application to a field test.

PubMed

Tang, Guoping; Watson, David B; Wu, Wei-Min; Schadt, Christopher W; Parker, Jack C; Brooks, Scott C

2013-04-02

We amended a shallow fast-flowing uranium (U) contaminated aquifer with emulsified vegetable oil (EVO) and subsequently monitored the biogeochemical responses for over a year. Using a biogeochemical model developed in a companion article (Tang et al., Environ. Sci. Technol.2013, doi: 10.1021/es304641b) based on microcosm tests, we simulated geochemical and microbial dynamics in the field test during and after the 2-h EVO injection. When the lab-determined parameters were applied in the field-scale simulation, the estimated rate coefficient for EVO hydrolysis in the field was about 1 order of magnitude greater than that in the microcosms. Model results suggested that precipitation of long-chain fatty acids, produced from EVO hydrolysis, with Ca in the aquifer created a secondary long-term electron donor source. The model predicted substantial accumulation of denitrifying and sulfate-reducing bacteria, and U(IV) precipitates. The accumulation was greatest near the injection wells and along the lateral boundaries of the treatment zone where electron donors mixed with electron acceptors in the groundwater. While electron acceptors such as sulfate were generally considered to compete with U(VI) for electrons, this work highlighted their role in providing electron acceptors for microorganisms to degrade complex substrates thereby enhancing U(VI) reduction and immobilization.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lunden, Melissa M.; Delp, William W.

Effective exhaust hoods can mitigate the indoor air quality impacts of pollutant emissions from residential cooking. This study reports capture efficiencies (CE) measured for cooking generated particles for scripted cooking procedures in a 121-m3 chamber with kitchenette. CEs also were measured for burner produced CO2 during cooking and separately for pots and pans containing water. The study used four exhaust hoods previously tested by Delp and Singer (Environ. Sci. Technol., 2012, 46, 6167-6173). For pan-frying a hamburger over medium heat on the back burner, CEs for particles were similar to those for burner produced CO2 and mostly above 80percent. Formore » stir-frying green beans in a wok (high heat, front burner), CEs for burner CO2 during cooking varied by hood and airflow: CEs were 34-38percent for low (51?68 L s-1) and 54?72percent for high (109?138 L s-1) settings. CEs for 0.3?2.0 ?m particles during front burner stir-frying were 3?11percent on low and 16?70percent on high settings. Results indicate that CEs measured for burner CO2 are not predictive of CEs of cooking-generated particles under all conditions, but they may be suitable to identify devices with CEs above 80percent both for burner combustion products and for cooking-related particles.« less

Emission Spectroscopy of Atmospheric-Pressure Ball Plasmoids: Higher Energy Reveals a Rich Chemistry

NASA Astrophysics Data System (ADS)

Dubowsky, Scott E.; Rose, Amber Nicole; Glumac, Nick; McCall, Benjamin J.

2017-06-01

Ball plasmoids (self-sustaining spherical plasmas) are a particularly unique example of a non-equilibrium air plasma. These plasmoids have lifetimes on the order of hundreds of milliseconds without an external power source, however, current models dictate that a ball plasmoid should recombine in a millisecond or less. Ball plasmoids are considered to be a laboratory analogue of natural ball lightning, a phenomenon that has eluded scientific explanation for centuries. We are searching for the underlying physicochemical mechanism(s) by which ball plasmoids and (by extension) ball lightning are stabilized using a variety of diagnostic techniques. This presentation will focus on optical emission spectroscopy (OES) of ball plasmoid discharges between 190-850 nm. The previous generation of OES measurements of this system showed emission from only a few atomic and molecular species, however, the energy available for the discharges in these experiments was limited by the size of the capacitor banks and voltages to which the capacitor banks were charged. We are capable of generating plasmoids at much higher energies, and as a result we are the first to report a very rich chemistry previously not observed in ball plasmoids. We have identified signals from species including NO A^{2}Σ^{+}→X^{2}Π, OH A^{2}Σ^{+}→X^{2}Π, NH A^{3}Π→X^{3}Σ^{-}, AlO A^{2}Π→X^{2}Σ^{+}, NH^{+} B^{2}Δ→X^{2}Π, W I, Al I, Cu I, and H_{α}, all of which have not yet been reported for this system. Analysis of the emission spectra and fitting procedures will be discussed, rotational temperatures of constituent species will be reported, and theories of ball plasmoid stabilization based upon these new results will be presented. Versteegh, A.; Behringer, K.; Fantz, U.; Fussman, G.; Jüttner, B.; Noack, S. Plas. Sour. Sci. Technol. 2008, 17(2), 024014 Stephan, K. D.; Dumas, S.; Komala-Noor, L.; McMinn, J. Plas. Sour. Sci. Technol. 2013, 22(2), 025018

Self-Organized Composition Modulation During Epitaxial Growth

NASA Astrophysics Data System (ADS)

Barabási

1998-03-01

There is extensive recent experimental evidence of spontaneous superlattice (SL) formation in various II-VI and III-V semiconductors. Here we propose an atomistic mechanism responsible for SL formation, and derive a relation predicting the temperature, flux and miscut dependence of the SL layer thickness(A.-L. Barabási, Appl. Phys. Lett.) 70, 764 (1996).. Moreover, the model explains the existence of a critical miscut angle below which no SL is formed, in agreement with results on ZnSeTe(S.P Ahrenkiel et al.), Phys. Rev. Lett. 75, 1586 (1995)., and predicts the formation of a platelet structure for deposition onto high symmetry surfaces, similar to that observed in InAsSb(A.G. Norman, et al.) Semicond. Sci. Technol. 8, S9 (1991).. Work done in collaboration with I. Daruka and J.K. Furdyna.

Experimental identification of nonlinear coupling between (intermediate, small)-scale microturbulence and an MHD mode in the core of a superconducting tokamak

NASA Astrophysics Data System (ADS)

Sun, P. J.; Li, Y. D.; Ren, Y.; Zhang, X. D.; Wu, G. J.; Xu, L. Q.; Chen, R.; Li, Q.; Zhao, H. L.; Zhang, J. Z.; Shi, T. H.; Wang, Y. M.; Lyu, B.; Hu, L. Q.; Li, J.; The EAST Team

2018-01-01

In this paper, we present clear experimental evidence of core region nonlinear coupling between (intermediate, small)-scale microturbulence and an magnetohydrodynamics (MHD) mode during the current ramp-down phase in a set of L-mode plasma discharges in the experimental advanced superconducting tokamak (EAST, Wan et al (2006 Plasma Sci. Technol. 8 253)). Density fluctuations of broadband microturbulence (k\\perpρi˜2{-}5.2 ) and the MHD mode (toroidal mode number m = -1 , poloidal mode number n = 1 ) are measured simultaneously, using a four-channel tangential CO2 laser collective scattering diagnostic in core plasmas. The nonlinear coupling between the broadband microturbulence and the MHD mode is directly demonstrated by showing a statistically significant bicoherence and modulation of turbulent density fluctuation amplitude by the MHD mode.

A spin-orbit coupling for a neutral particle from Lorentz symmetry breaking effects in the CPT-odd sector of the Standard Model Extension

NASA Astrophysics Data System (ADS)

Belich, H.; Bakke, K.

2015-07-01

We start by investigating the arising of a spin-orbit coupling and a Darwin-type term that stem from Lorentz symmetry breaking effects in the CPT-odd sector of the Standard Model Extension. Then, we establish a possible scenario of the violation of the Lorentz symmetry that gives rise to a linear confining potential and an effective electric field in which determines the spin-orbit coupling for a neutral particle analogous to the Rashba coupling [E. I. Rashba, Sov. Phys. Solid State 2, 1109 (1960)]. Finally, we confine the neutral particle to a quantum dot [W.-C. Tan and J. C. Inkson, Semicond. Sci. Technol. 11, 1635 (1996)] and analyze the influence of the linear confining potential and the spin-orbit coupling on the spectrum of energy.

Turbulent equipartition pinch of toroidal momentum in spherical torus

NASA Astrophysics Data System (ADS)

Hahm, T. S.; Lee, J.; Wang, W. X.; Diamond, P. H.; Choi, G. J.; Na, D. H.; Na, Y. S.; Chung, K. J.; Hwang, Y. S.

2014-12-01

We present a new analytic expression for turbulent equipartition (TEP) pinch of toroidal angular momentum originating from magnetic field inhomogeneity of spherical torus (ST) plasmas. Starting from a conservative modern nonlinear gyrokinetic equation (Hahm et al 1988 Phys. Fluids 31 2670), we derive an expression for pinch to momentum diffusivity ratio without using a usual tokamak approximation of B ∝ 1/R which has been previously employed for TEP momentum pinch derivation in tokamaks (Hahm et al 2007 Phys. Plasmas 14 072302). Our new formula is evaluated for model equilibria of National Spherical Torus eXperiment (NSTX) (Ono et al 2001 Nucl. Fusion 41 1435) and Versatile Experiment Spherical Torus (VEST) (Chung et al 2013 Plasma Sci. Technol. 15 244) plasmas. Our result predicts stronger inward pinch for both cases, as compared to the prediction based on the tokamak formula.

The simulated clinical environment: Cognitive and emotional impact among undergraduates.

PubMed

Tremblay, Marie-Laurence; Lafleur, Alexandre; Leppink, Jimmie; Dolmans, Diana H J M

2017-02-01

Simulated clinical immersion (SCI) is used in undergraduate healthcare programs to expose the learner to real-life situations in authentic simulated clinical environments. For novices, the environment in which the simulation occurs can be distracting and stressful, hence potentially compromising learning. This study aims to determine whether SCI (with environment) imposes greater extraneous cognitive load and stress on undergraduate pharmacy students than simulated patients (SP) (without environment). It also aims to explore how features of the simulated environment influence students' perception of learning. In this mixed-methods study, 143 undergraduate pharmacy students experienced both SCI and SP in a crossover design. After the simulations, participants rated their cognitive load and emotions. Thirty-five students met in focus groups to explore their perception of learning in simulation. Intrinsic and extraneous cognitive load and stress scores in SCI were significantly but modestly higher compared to SP. Qualitative findings reveal that the physical environment in SCI generated more stress and affected students? focus. In SP, students concentrated on clinical reasoning. SCI stimulated a focus on data collection but impeded in-depth problem solving processes. The physical environment in simulation influences what and how students learn. SCI was reported as more cognitively demanding than SP. Our findings emphasize the need for the development of adapted instructional design guidelines in simulation for novices.

Abundance and antibiotic susceptibility of Vibrio spp. isolated from microplastics

NASA Astrophysics Data System (ADS)

Laverty, A. L.; Darr, K.; Dobbs, F. C.

2016-02-01

In recent years, there has been a growing concern for `microplastics' (particles < 5 mm) in the marine environment. Since plastics degrade very slowly, they remain in the environment on much longer timescales than most natural substrates and can thus provide a novel habitat for colonization by microbial communities (Zettler et al. 2013 Environ. Sci. Technol. 47:7137). The full spectrum of relationships between microplastics and bacteria, however, is little understood. In summer 2015, we examined microplastics collected from a tributary of the lower Chesapeake Bay and determined the presence, abundance, and antibiotic-resistance profiles of Vibrio spp. found on them. We collected 22 microplastic pieces, paired seawater samples, and from them cultured 44 putative Vibrio spp. isolates, 18 of which were PCR-confirmed as V. parahaemolyticus and 3 as V. vulnificus. There were no PCR-confirmed V. cholerae isolates. We used the Kirby-Bauer disk diffusion susceptibility test to examine the isolates' response to six antibiotics: chloramphenicol (30μg), gentamicin (10μg), ampicillin (10μg), streptomycin (10μg), tetracycline (30μg), and rifampin (5μg). Vibrio isolates were susceptible to three or more of the six antibiotics tested and all were susceptible to tetracycline and chloramphenicol. There were no apparent differences between the antibiotic susceptibilities of vibrios isolated from microplastics compared to those from the water column. In every instance tested, vibrios on microplastics were enriched by at least two orders of magnitude compared to those from paired seawater samples. This study demonstrates that microplastic particles serve as a habitat for Vibrio species, in particular V. vulnificus and V. parahaemolyticus, confirming the conjecture of Zettler et al. (2013) that plastics may serve as a vector for these and other potentially pathogenic bacteria.

Hazard assessment of exhaust emissions - The next generation of fast and reliable tools for in vitro screening

NASA Astrophysics Data System (ADS)

Rothen-Rutishauser, B.

2017-12-01

Hazard assessment of exhaust emissions - The next generation of fast and reliable tools for in vitro screening Barbara Rothen-Rutishauser Adolphe Merkle Institute, University of Fribourg, Switzerland; barbara.rothen@unifr.ch Pollution by vehicles is a major problem for the environment due to the various components in the exhaust gasses that are emitted into the atmosphere. A large number of epidemiological studies demonstrate the profound impact of vehicle emissions upon human health [1-3]. Such studies however, are unable to attribute a given subset of emissions to a certain adverse effect, which renders decision making difficult. Standardized protocols for exhaust toxicity assessment are lacking and it relies in many aspects on epidemiological and in vivo studies (animals), which are very time and cost-intensive and suffer from considerable ethical issues. An overview about the current state of research and clinical aspects in the field, as well as about the development of sophisticated in vitro approaches mimicking the inhalation of airborne particles / exhaust for the toxicological testing of engine emissions will be provided. Data will be presented that show that the combination of an air-liquid exposure system and 3D lung-cell culture model offers an adequate tool for fast and reliable investigations of complete exhaust toxicity as well as the effects of particulate fraction [4,5]. This approach yields important results for novel and improved emission technologies in the early stages of product development. [1] Donaldson et al. Part Fibre Toxicol 2005, 2: 10. [2] Ghio et al. J Toxicol Environ Health B Crit Rev 2012, 15: 1-21. [3] Peters et al. Res Rep Health Eff Inst 2009, 5-77. [4] Bisig et al. Emiss Control Sci Technol 2015, 1: 237-246. [5] Steiner et al. Atmos Environ 2013, 81: 380-388.

Diclofenac degradation by heterogeneous photocatalysis with Fe3O4/Ti x O y /activated carbon fiber composite synthesized by ultrasound irradiation

NASA Astrophysics Data System (ADS)

Moreno-Valencia, E. I.; Paredes-Carrera, S. P.; Sánchez-Ochoa, J. C.; Flores-Valle, S. O.; Avendaño-Gómez, J. R.

2017-11-01

In this work, a photocatalytic system to degrade diclofenac was developed using a composite Fe3O4/Ti x O y on an activated carbon fiber. Diclofenac is widely used as an anti-inflammatory compound worldwide and it is constantly being added as waste in the environment (Heberer 2002 J. Hydrol. 266 175-89), exceeding the permissible maximum concentration in the wastewater (GEO-3 2002 Programa de las Naciones Unidas para el Medio Ambiente; Golet et al 2003 Environ. Sci. Technol. 37 3243-9 Oviedo et al 2010 Environ. Toxicol. Pharmacol. 29 9-43 Le-Minh et al 2010 Water Res. 44 4295-323 Legrini et al 1993 Chem. Rev. 1093 671-98). The composite was synthesized by sol-gel technique with and without ultrasound irradiation (Singh and Nakate 2014 J. Nanopart. 2014 326747). The solids were deposited by ultrasound irradiation on active carbon fiber in order to optimize the diclofenac degradation. The solids were characterized by x-ray diffraction (XRD), nitrogen physisorption (BET), and scanning electron microscopy with EDS microanalysis (SEM-EDS). The crystal size was calculated with the Debye-Scherrer equation, and the band gap values by the diffuse reflectance method. The evaluation process was studied by UV-vis spectroscopy (Rizzoa et al 2009 Water Res. 43 979-88). It was found that in this synthesis method (ultrasound), textural properties such as porosity, specific surface area and morphology depend on the ultrasound irradiation. The proposed system, Fe3O4/titanium oxide hydrate showed better degradation profile than TiO2 anatase phase; the increase of diclofenac degradation was attributed to the textural properties of the composite, it avoids the filtering process since the separation can be achieved by magnetizing and/or decantation.

New Low-Temperature Magnetic Data Acquired on Synthetic Lepidocrocite

NASA Astrophysics Data System (ADS)

Guyodo, Y.; Bonville, P.; Ona-Nguema, G.; Carvallo, C.; Wang, Y.; Morin, G.

2007-12-01

Lepidocrocite (γ-FeOOH) is an iron oxyhydroxide commonly found in the environment, which is assumed to be antiferromagnetic with a small ferromagnetic-like behavior and a Néel temperature of about 50K (e.g., Hirt et al., 2002, JGR, 107, 10.1029/2001JB000242). It is currently used as starting material in bio- reduction experiments leading to the formation of Fe(II)-bearing minerals such as green rusts, magnetite, and siderite (e.g., Ona-Nguema et al., 2002, Environ. Sci. Technol., 36, 16-20). Both initial and resulting materials are being characterized using various techniques including low-temperature magnetic methods. At this meeting, results obtained on the initial synthetic lepidocrocite samples will be presented, which describe an unusual magnetic behavior. In particular, field cooled and zero field cooled induced magnetization curves (obtained using a 5mT magnetic induction) merge at a temperature around 150K (well above 50K). Below this temperature, the difference between the two curves can be qualified as a remanent magnetization, acquired during cooling of the sample in the presence of a magnetic field. As a consequence, some ferromagnetic-like behavior persists at temperatures above the admitted Néel temperature. The cooling/warming cycle of the room temperature remanent magnetization (acquired using a 2.5T magnetic induction) also indicates that some remanence can be acquired well above that temperature. Other types of measurement have been performed in order to better constrain the low-temperature magnetic behavior of these samples, in particular using a high-field VSM.

Comparison of Experimenal Photooxidation Rates and Patterns in Glass- and Water-Based Oil Slicks with Daily Weathering Observed in the Gulf of Mexico

NASA Astrophysics Data System (ADS)

Sharpless, C.; Aeppli, C.; Reddy, C. M.; Swarthout, B.; Stewart, O. C.; Walters, M.; Valentine, D. L.

2016-02-01

Photooxidation is a well-known degradation route for toxic components of oil (e.g., PAHs). However, recent research suggests that it may play a broader role by enhancing oil's dark1 and photo-toxicity2 and producing persistent, oxidized hydrocarbons.3To better understand photooxidation's importance to oil weathering in marine systems, we are combining laboratory studies with field measurements of compositional changes under controlled conditions. Lab experiments have employed a solar simulator to photooxidize slicks of Dorado Well crude oil on water (Instant Ocean) and glass surfaces. Qualitatively similar compositional changes were seen in both systems, such as rapid loss of aromatics and production of oxidized hydrocarbons as assessed by GCMS, GCxGC, TLC-FID, and FTIR. Rates were much faster on water, a finding tentatively ascribed to the film on glass ( 750 um) being much thicker than on water ( 140 um). Further experiments have been conducted with thinner films on glass, and the results are being analyzed to clarify the importance of film thickness versus surface substrate for photoxidation kinetics. Naturally weathered samples were also collected in the Gulf during a cruise in June, 2015. Surface slicks from natural seeps were tracked and sampled daily under very calm seas with full sun, and solar irradiance was simultaneously measured. These samples, currently undergoing GCxGC and TLC-FID analyses, provide a unique reference with which to assess in-situ transformation rates and compositional changes due to photooxidation. Comparison between results from the field samples and lab experiments should help clarify the absolute contribution of photooxidation to marine oil weathering and improve efforts to use lab results to constrain estimates of environmental transformation rates. 1. D. Rial et al. J. Haz. Mat. 2013, 260, 67 2. J.P. Incardona et al. Proc. Natl. Acad. Sci. 2012, 109, E51 3. C. Aeppli et al. Environ. Sci. Technol. 2012, 46, 8799

Laser irradiance scaling in polar direct drive implosions on the National Ignition Facility

DOE PAGES

Murphy, T. J.; Krasheninnikova, N. S.; Kyrala, G. A.; ...

2015-09-17

Polar-direct-drive experiments conducted at the National Ignition Facility [E. I. Moses, Fusion Sci. Technol. 54, 361 (2008)] performed at laser irradiance between 1 and 2×10 15 W/cm 2 exhibit increased hard x-ray emission, decreased neutron yield, and reduced areal density as the irradiance is increased. Experimental x-ray images at the higher irradiances show x-ray emission at the equator, as well as degraded symmetry, that is not predicted in hydrodynamic simulations using flux-limited energy transport, but that appear when non-local electron transport together with a model to account for cross beam energy transfer (CBET) is utilized. The reduction in laser powermore » for equatorial beams required in the simulations to reproduce the effects of CBET on the observed symmetry also reproduces the yield degradation consistent with experimental data.« less

Damage healing ability of a shape-memory-polymer-based particulate composite with small thermoplastic contents

NASA Astrophysics Data System (ADS)

Nji, Jones; Li, Guoqiang

2012-02-01

The purpose of this study is to investigate the potential of a shape-memory-polymer (SMP)-based particulate composite to heal structural-length scale damage with small thermoplastic additive contents through a close-then-heal (CTH) self-healing scheme that was introduced in a previous study (Li and Uppu 2010 Comput. Sci. Technol. 70 1419-27). The idea is to achieve reasonable healing efficiencies with minimal sacrifice in structural load capacity. By first closing cracks, the gap between two crack surfaces is narrowed and a lesser amount of thermoplastic particles is required to achieve healing. The particulate composite was fabricated by dispersing copolyester thermoplastic particles in a shape memory polymer matrix. It is found that, for small thermoplastic contents of less than 10%, the CTH scheme followed in this study heals structural-length scale damage in the SMP particulate composite to a meaningful extent and with less sacrifice of structural capacity.

Oxygen adsorption and incorporation at irradiated GaN(0001) and GaN(0001¯) surfaces: First-principles density-functional calculations

NASA Astrophysics Data System (ADS)

Sun, Qiang; Selloni, Annabella; Myers, T. H.; Doolittle, W. Alan

2006-11-01

Density functional theory calculations of oxygen adsorption and incorporation at the polar GaN(0001) and GaN(0001¯) surfaces have been carried out to explain the experimentally observed reduced oxygen concentration in GaN samples grown by molecular beam epitaxy in the presence of high energy (˜10keV) electron beam irradiation [Myers , J. Vac. Sci. Technol. B 18, 2295 (2000)]. Using a model in which the effect of the irradiation is to excite electrons from the valence to the conduction band, we find that both the energy cost of incorporating oxygen impurities in deeper layers and the oxygen adatom diffusion barriers are significantly reduced in the presence of the excitation. The latter effect leads to a higher probability for two O adatoms to recombine and desorb, and thus to a reduced oxygen concentration in the irradiated samples, consistent with experimental observations.

RAPID COMMUNICATION: Optical distortion correction for liquid droplet visualization using the ray tracing method: further considerations

NASA Astrophysics Data System (ADS)

Minor, G.; Oshkai, P.; Djilali, N.

2007-11-01

The original work of Kang et al (2004 Meas. Sci. Technol. 15 1104 12) presents a scheme for correcting optical distortion caused by the curved surface of a droplet, and illustrates its application in PIV measurements of the velocity field inside evaporating liquid droplets. In this work we re-derive the correction algorithm and show that several terms in the original algorithm proposed by Kang et al are erroneous. This was not evident in the original work because the erroneous terms are negligible for droplets with approximately hemispherical shapes. However, for the more general situation of droplets that have shapes closer to that of a sphere, with heights much larger than their contact-line radii, these errors become quite significant. The corrected algorithm is presented and its application illustrated in comparison with that of Kang et al.

Exact cone beam reconstruction formulae for functions and their gradients for spherical and flat detectors

NASA Astrophysics Data System (ADS)

Louis, Alfred K.

2016-11-01

We derive unified inversion formulae for the cone beam transform similar to the Radon transform. Reinterpreting Grangeat’s formula we find a relation between the Radon transform of the gradient of the searched-for function and a quantity computable from cone beam data. This gives a uniqueness result for the cone beam transform of compactly supported functions under much weaker assumptions than the Tuy-Kirillov condition. Furthermore this relation leads to an exact formula for the direct calculation of derivatives of the density distribution; but here, similar to the classical Radon transform, complete Radon data are needed, hence the Tuy-Kirillov condition has to be imposed. Numerical experiments reported in Hahn B N et al (2013 Meas. Sci. Technol. 24 125601) indicate that these calculations are less corrupted by beam-hardening noise. Finally, we present flat detector versions for these results, which are mathematically less attractive but important for applications.

Use of Threshold of Toxicological Concern (TTC) with High ...

EPA Pesticide Factsheets

Although progress has been made with HTS (high throughput screening) in profiling biological activity (e.g., EPA’s ToxCast™), challenges arise interpreting HTS results in the context of adversity & converting HTS assay concentrations to equivalent human doses for the broad domain of commodity chemicals. Here, we propose using TTC as a risk screening method to evaluate exposure ranges derived from NHANES for 7968 chemicals. Because the well-established TTC approach uses hazard values derived from in vivo toxicity data, relevance to adverse effects is robust. We compared the conservative TTC (non-cancer) value of 90 μg/day (1.5 μg/kg/day) (Kroes et al., Fd Chem Toxicol, 2004) to quantitative exposure predictions of the upper 95% credible interval (UCI) of median daily exposures for 7968 chemicals in 10 different demographic groups (Wambaugh et al., Environ Sci Technol. 48:12760-7, 2014). Results indicate: (1) none of the median values of credible interval of exposure for any chemical in any demographic group was above the TTC; & (2) fewer than 5% of chemicals had an UCI that exceeded the TTC for any group. However, these median exposure predictions do not cover highly exposed (e.g., occupational) populations. Additionally, we propose an expanded risk-based screening workflow that comprises a TTC decision tree that includes screening compounds for structural alerts for DNA reactivity, OPs & carbamates as well as a comparison with bioactivity-based margins of

Creating wealth from groundwater for dollar-a-day farmers: Where the silent revolution and the four revolutions to end rural poverty meet

NASA Astrophysics Data System (ADS)

Polak, Paul; Yoder, Robert

2006-03-01

More than 550 million of the current 1.1 billion people earning less than 1-a-day earn a living from agriculture in developing countries. A revolution in water control is needed to develop and mass-disseminate new, affordable, small-plot irrigation technologies. A revolution in agriculture is required to enable smallholders to produce high-value, marketable, labor-intensive cash crops. A revolution in markets is needed to open access to markets for the crops they produce and the inputs they need to produce them. Finally, a revolution in design, based on the ruthless pursuit of affordability, is needed to harness shallow groundwater. The experiences of suppliers of treadle pumps, low-cost drip irrigation and water storage systems were examined. The wealth these technologies generated, coupled with falling prices for small diesel pumps in countries like India and China, created a suitable environment for the rapid adoption of affordable diesel pump tubewells, which in turn created vigorous water markets and expanded access to affordable irrigation water for smallholders. The combination of smallholder-centered revolutions, along with the ‘silent revolution in groundwater’ described by Llamas and Martinez-Santos (Water Sci Technol 51(8):167-174, 2005) provide new practical options for meeting the UN Millennium Development Goals on poverty and hunger by 2015.

The SOA formation model combined with semiempirical quantum chemistry for predicting UV-Vis absorption of secondary organic aerosols.

PubMed

Zhong, Min; Jang, Myoseon; Oliferenko, Alexander; Pillai, Girinath G; Katritzky, Alan R

2012-07-07

A new model for predicting the UV-visible absorption spectra of secondary organic aerosols (SOA) has been developed. The model consists of two primary parts: a SOA formation model and a semiempirical quantum chemistry method. The mass of SOA is predicted using the PHRCSOA (Partitioning Heterogeneous Reaction Consortium Secondary Organic Aerosol) model developed by Cao and Jang [Environ. Sci. Technol., 2010, 44, 727]. The chemical composition is estimated using a combination of the kinetic model (MCM) and the PHRCSOA model. The absorption spectrum is obtained by taking the sum of the spectrum of each SOA product calculated using a semiempirical NDDO (Neglect of Diatomic Differential Overlap)-based method. SOA was generated from the photochemical reaction of toluene or α-pinene at different NO(x) levels (low NO(x): 24-26 ppm, middle NO(x): 49 ppb, high NO(x): 104-105 ppb) using a 2 m(3) indoor Teflon film chamber. The model simulation reasonably agrees with the measured absorption spectra of α-pinene SOA but underestimates toluene SOA under high and middle NO(x) conditions. The absorption spectrum of toluene SOA is moderately enhanced with increasing NO(x) concentrations, while that of α-pinene SOA is not affected. Both measured and calculated UV-visible spectra show that the light absorption of toluene SOA is much stronger than that of α-pinene SOA.

Bacterial population dynamics during uranium reduction andre-oxidation: Application of a novel high density oligonucleotidemicroarray approach

DOE Office of Scientific and Technical Information (OSTI.GOV)

Brodie, Eoin L.; DeSantis, Todd Z.; Joyner, Dominique C.

2006-01-30

Reduction of soluble uranium U(VI) to less-soluble uraniumU(IV) is a promising approach to minimize migration from contaminatedaquifers. It is generally assumed that, under constant reducingconditions, U(IV) is stable and immobile; however, in a previous study,we documented reoxidation of U(IV) under continuous reducing conditions(Wan et al., Environ. Sci. Technol. 2005, 39:6162 6169). To determine ifchanges in microbial community composition were a factor in U(IV)reoxidation, we employed a high-density phylogenetic DNA microarray (16Smicroarray) containing 500,000 probes to monitor changes in bacterialpopulations during this remediation process. Comparison of the 16Smicroarray with clone libraries demonstrated successful detection andclassification of most clone groups. Analysis ofmore » the most dynamic groupsof 16S rRNA gene amplicons detected by the 16S microarray identified fiveclusters of bacterial subfamilies responding in a similar manner. Thisapproach demonstrated that amplicons of known metal-reducing bacteriasuch as Geothrix fermentans (confirmed by quantitative PCR) and thosewithin the Geobacteraceae were abundant during U(VI) reduction and didnot decline during the U(IV) reoxidation phase. Significantly, it appearsthat the observed reoxidation of uranium under reducing conditionsoccurred despite elevated microbial activity and the consistent presenceof metal-reducing bacteria. High-density phylogenetic microarraysconstitute a powerful tool, enabling the detection and monitoring of asubstantial portion of the microbial population in a routine, accurate,and reproducible manner.« less

Tritium Decay Helium-3 Effects in Tungsten

DOE Office of Scientific and Technical Information (OSTI.GOV)

Shimada, M.; Merrill, B. J.

2016-06-01

A critical challenge for long-term operation of ITER and beyond to a Demonstration reactor (DEMO) and future fusion reactor will be the development of plasma-facing components (PFCs) that demonstrate erosion resistance to steady-state/transient heat fluxes and intense neutral/ion particle fluxes under the extreme fusion nuclear environment, while at the same time minimizing in-vessel tritium inventories and permeation fluxes into the PFC’s coolant. Tritium will diffuse in bulk tungsten at elevated temperatures, and can be trapped in radiation-induced trap site (up to 1 at. % T/W) in tungsten [1,2]. Tritium decay into helium-3 may also play a major role in microstructuralmore » evolution (e.g. helium embrittlement) in tungsten due to relatively low helium-4 production (e.g. He/dpa ratio of 0.4-0.7 appm [3]) in tungsten. Tritium-decay helium-3 effect on tungsten is hardly understood, and its database is very limited. Two tungsten samples (99.99 at. % purity from A.L.M.T. Co., Japan) were exposed to high flux (ion flux of 1.0x1022 m-2s-1 and ion fluence of 1.0x1026 m-2) 0.5%T2/D2 plasma at two different temperatures (200, and 500°C) in Tritium Plasma Experiment (TPE) at Idaho National Laboratory. Tritium implanted samples were stored at ambient temperature in air for more than 3 years to investigate tritium decay helium-3 effect in tungsten. The tritium distributions on plasma-exposed was monitored by a tritium imaging plate technique during storage period [4]. Thermal desorption spectroscopy was performed with a ramp rate of 10°C/min up to 900°C to outgas residual deuterium and tritium but keep helium-3 in tungsten. These helium-3 implanted samples were exposed to deuterium plasma in TPE to investigate helium-3 effect on deuterium behavior in tungsten. The results show that tritium surface concentration in 200°C sample decreased to 30 %, but tritium surface concentration in 500°C sample did not alter over the 3 years storage period, indicating possible tritium retention in helium-3 bubble. This paper reports the initial experimental observation of tritium-decay helium-3 in tungsten exposed to deuterium/tritium plasma along with electron microscope analysis and also discusses a Tritium Migration Analysis Program (TMAP) analysis of tritium-decay helium-3 effects on tritium retention in tungsten for DEMO and future fusion reactor. [1] Y. Hatano, et.al., Nucl. Fusion 53 (2013) 073006 [2] M. Shimada, et.al., Nucl. Fusion 55 (2015) 013008 [3] M. Sawan, Fus. Sci. Technol. 66 (2014) 272 [4] T. Otsuka, Fus. Sci. Technol. 60 (2011) 1539 This work was prepared for the U.S. Department of Energy, Office of Fusion Energy Sciences, under the DOE Idaho Field Office contract number DE-AC07-05ID14517.« less

Annually-layered lake sediments reveal strongly increased release of persistent chemicals due to accelerated glacier melting

NASA Astrophysics Data System (ADS)

Anselmetti, Flavio S.; Blüthgen, Nancy; Bogdal, Christian; Schmid, Peter

2010-05-01

Melting glaciers may represent a secondary source of chemical pollutants that have previously been incorporated and stored in the ice. Of particular concern are persistent organic pollutants (POPs), such as the insecticide dichlorodiphenyl trichloroethane (DDT) and industrial chemicals like polychlorinated biphenyls (PCBs), which are hazardous environmental contaminants due to their persistent, bioaccumulative and toxic properties. They were introduced in the 1930s and eventually banned in the 1970s. After release into the environment these chemicals were atmospherically transported to even remote areas such as the Alps and were deposited and stored in glaciers. Ongoing drastic glacier melting due to global warming, which is expected to further accelerate, implies the significance of studying the fate of these 'legacy pollutants'. Proglacial lake sediments provide well-dated and high-resolution archives to reconstruct timing and quantities of such a potentially hazardous remobilization. The goal of this study is to reconstruct the historical inputs of POPs into remote alpine lakes and to investigate the accelerated release of POPs from melting glaciers. Due to their lipophilic character, these chemicals exhibit a high tendency to adsorb to particles whereas concentrations in water are expected to be low. Therefore, quantitative determination in annually-layered lake sediment provides an excellent way to investigate the temporal trend of inputs into lakes that act as particle sinks. For this purpose, sediment cores were sampled from proglacial lakes in the Bernese Alps (Switzerland), which are exclusively fed by glacial melt waters. For comparison, cores were also taken from nearby high-alpine lakes located in non-glaciated catchments, which only should record the initial atmospheric fall-out. Sediment layers were dated by annual varve counting and radionuclide measurements; they cover the time period from the mid 20th century to today. The measured time series of POPs indicate indeed different patterns in proglacial and non-glacial lakes. Similar to lowland Swiss plateau lakes [1,2], high-alpine lakes show a historic maximum of POP-concentrations some decades ago, which is synchronous with their primary use at that time. However, only proglacial lakes exhibit a dramatic re-increase in POP-input during the last years, thus confirming the crucial role of glaciers as reservoir and secondary source of these pollutants. The burden of pollutants in these sediments due to glacier melting is already in the same range as the earlier accumulations from direct atmospheric fall-out. Furthermore, the undiminished increase of the fluxes of many POPs into the sediment of proglacial lakes does not yet indicate an exhaust of the glacial inventory of these contaminants. Considering ongoing global warming and accelerated massive glacier melting predicted for the future, our study indicates the potential for significant environmental hazards due to pollutants delivered into such remote mountainous areas. [3] [1] Zennegg M. et al., Chemosphere 2007, 67, 1754. [2] Bogdal C. et al., Env. Sci. & Technol. 2008, 47, 6817. [3] Bogdal C. et al., Env. Sci. & Technol. 2009, 43, 8173.

Navigating Tensions Between Conceptual and Metaconceptual Goals in the Use of Models

NASA Astrophysics Data System (ADS)

Delgado, Cesar

2015-04-01

Science education involves learning about phenomena at three levels: concrete (facts and generalizations), conceptual (concepts and theories), and metaconceptual (epistemology) (Snir et al. in J Sci Educ Technol 2(2):373-388, 1993). Models are key components in science, can help build conceptual understanding, and may also build metaconceptual understanding. Technology can transform teaching and learning by turning models into interactive simulations that learners can investigate. This paper identifies four characteristics of models and simulations that support conceptual learning but misconstrue models and science at a metaconceptual level. Ahistorical models combine the characteristics of several historical models; they conveniently compile ideas but misrepresent the history of science (Gilbert in Int J Sci Math Educ 2(2):115-130, 2004). Teleological models explain behavior in terms of a final cause; they can lead to useful heuristics but imply purpose in processes driven by chance and probability (Talanquer in Int J Sci Educ 29(7):853-870, 2007). Epistemological overreach occurs when models or simulations imply greater certainty and knowledge about phenomena than warranted; conceptualizing nature as being well known (e.g., having a mathematical structure) poses the danger of conflating model and reality or data and theory. Finally, models are inevitably ontologically impoverished. Real-world deviations and many variables are left out of models, as models' role is to simplify. Models and simulations also lose much of the sensory data present in phenomena. Teachers, designers, and professional development designers and facilitators must thus navigate the tension between conceptual and metaconceptual learning when using models and simulations. For each characteristic, examples are provided, along with recommendations for instruction and design. Prompts for explicit reflective activities around models are provided for each characteristic

Rapid Measurements of Aerosol Size Distribution and Hygroscopic Growth via Image Processing with a Fast Integrated Mobility Spectrometer (FIMS)

NASA Astrophysics Data System (ADS)

Wang, Y.; Pinterich, T.; Spielman, S. R.; Hering, S. V.; Wang, J.

2017-12-01

Aerosol size distribution and hygroscopicity are among key parameters in determining the impact of atmospheric aerosols on global radiation and climate change. In situ submicron aerosol size distribution measurements commonly involve a scanning mobility particle sizer (SMPS). The SMPS scanning time is in the scale of minutes, which is often too slow to capture the variation of aerosol size distribution, such as for aerosols formed via nucleation processes or measurements onboard research aircraft. To solve this problem, a Fast Integrated Mobility Spectrometer (FIMS) based on image processing was developed for rapid measurements of aerosol size distributions from 10 to 500 nm. The FIMS consists of a parallel plate classifier, a condenser, and a CCD detector array. Inside the classifier an electric field separates charged aerosols based on electrical mobilities. Upon exiting the classifier, the aerosols pass through a three stage growth channel (Pinterich et al. 2017; Spielman et al. 2017), where aerosols as small as 7 nm are enlarged to above 1 μm through water or heptanol condensation. Finally, the grown aerosols are illuminated by a laser sheet and imaged onto a CCD array. The images provide both aerosol concentration and position, which directly relate to the aerosol size distribution. By this simultaneous measurement of aerosols with different sizes, the FIMS provides aerosol size spectra nearly 100 times faster than the SMPS. Recent deployment onboard research aircraft demonstrated that the FIMS is capable of measuring aerosol size distributions in 1s (Figure), thereby offering a great advantage in applications requiring high time resolution (Wang et al. 2016). In addition, the coupling of the FIMS with other conventional aerosol instruments provides orders of magnitude more rapid characterization of aerosol optical and microphysical properties. For example, the combination of a differential mobility analyzer, a relative humidity control unit, and a FIMS was used to measure aerosol hygroscopic growth. Such a system reduced the time of measuring the hygroscopic properties of submicron aerosols (six sizes) to less than three minutes in total, with an error within 1%. Pinterich et al. (2017) Aerosol Sci. Technol. accepted Spielman et al. (2017) Aerosol Sci. Technol. accepted Wang et al. (2016) Nature 539:416-419

EDITORIAL: Perspectives Perspectives

NASA Astrophysics Data System (ADS)

Dewhurst, Richard

2011-05-01

In this issue, we are delighted to publish the second in a series of articles under the banner of Perspectives. The series commenced in late 2008, when Udo Kaatze [1] published an article about the powerful technique of dielectric spectrometry for liquid measurements. In addition to examining the very wide frequency range from 10-6 Hz to 10-13 Hz, an outline of possible future developments was presented. Some challenging tasks for the future were briefly outlined. The format of the article was different to the usual style of a contributed paper or review article. Instead, it represented a short summary of recent work in the field and offered a viewpoint of an expert in the area. Its commentary noted several milestones that had been recently achieved, and then looked to the future. The Perspective format allowed the author to provide some opinion about the challenges of the future not normally permitted in a Topical Review. The journal now intends to publish several more Perspectives. For example, in this issue David Birch [2] presents a Perspective about another important measurement science, namely fluorescence detections and their future directions. These are based on an old technique which provided the basis for detecting the presence of molecular species. Successful research led to an understanding and description of the phenomenon of molecular fluorescence in terms of excited state energies, transitions, symmetries and rate parameters. More recently, using fluorescence as a probe, and with the exploitation of new technologies, new applications have included the study of protein, vision, photosynthesis, membranes and DNA. Indeed nowhere has fluorescence had more impact than in the biosciences. Once again, the intention of the Perspective article has been to highlight recent milestones within the field. Importantly, it also indicates some of the future challenges. Such Perspectives are an occasional series. They are not intended to deflect from the balance of MST, where about 20% of papers involve special features, special issues and review articles. The remaining 80% of papers are original, contributed, papers. Nevertheless, we hope readers will find that these new Perspectives are both useful commentaries and also provide an insight into the future of topical fields of research. References [1] Kaatze U 2008 Perspectives in dielectric measurement techniques for liquids Meas. Sci. Technol. 19 112001 [2] Birch D J S 2011 Fluorescence detections and directions Meas. Sci. Technol. 22 052002

Walking in water and on land after an incomplete spinal cord injury.

PubMed

Tamburella, Federica; Scivoletto, Giorgio; Cosentino, Elena; Molinari, Marco

2013-10-01

Although no data are available on the effects of water environment on the gait of subjects with spinal cord injury (SCI), hydrotherapy is used in the rehabilitation protocols of SCI patients. The aim of this study was to characterize gait features of subjects with incomplete SCI walking in water and on land in comparison with healthy controls (CTRLs) to identify the specificity of water environment on influencing gait in SCI subjects. This is a matched case-control study. Kinematic gait parameters and range of motion of joint angles of 15 SCI subjects and 15 CTRLs were analyzed. Compared with gait on land, gait in water of the SCI patients was characterized by speed and stance phase reduction, gait cycle time increment, and invariance of stride length and range of motion values. Comparison with CTRL data remarked that walking in water reduces gait differences between the groups. Furthermore, in water, the SCI subjects presented a reduction in variability of the hip and knee joint angles, whereas in the CTRLs, a larger variability was observed. Gait in water of the SCI subjects is associated with kinematic parameters more similar to those of the CTRLs, particularly regarding speed, stride length, and stance phase, supporting the idea that walking in a water environment may be of rehabilitative significance for SCI subjects.

Learning by Creating and Exchanging Objects: The SCY Experience

ERIC Educational Resources Information Center

De Jong, Ton; Van Joolingen, Wouter R.; Giemza, Adam; Girault, Isabelle; Hoppe, Ulrich; Kindermann, Jorg; Kluge, Anders; Lazonder, Ard W.; Vold, Vibeke; Weinberger, Armin; Weinbrenner, Stefan; Wichmann, Astrid; Anjewierden, Anjo; Bodin, Marjolaine; Bollen, Lars; D'Ham, Cedric; Dolonen, Jan; Engler, Jan; Geraedts, Caspar; Grosskreutz, Henrik; Hovardas, Tasos; Julien, Rachel; Lechner, Judith; Ludvigsen, Sten; Matteman, Yuri; Meistadt, Oyvind; Naess, Bjorge; Ney, Muriel; Pedaste, Margus; Perritano, Anthony; Rinket, Marieke; Von Schlanbusch, Henrik; Sarapuu, Tago; Schulz, Florian; Sikken, Jakob; Slotta, Jim; Toussaint, Jeremy; Verkade, Alex; Wajeman, Claire; Wasson, Barbara; Zacharia, Zacharias C.; Van Der Zanden, Martine

2010-01-01

Science Created by You (SCY) is a project on learning in science and technology domains. SCY uses a pedagogical approach that centres around products, called "emerging learning objects" (ELOs) that are created by students. Students work individually and collaboratively in SCY-Lab (the general SCY learning environment) on "missions" that are guided…

A Scheme for the Integrated Assessment of Mitigation Options

NASA Astrophysics Data System (ADS)

Held, H.; Edenhofer, O.

2003-04-01

After some consensus has been achieved that the global mean temperature will have increased by 1.4 to 5.8^oC at the end of this century in case of continued ``business as usual'' greenhouse gas emissions, society has to decide if or which mitigation measures should be taken. A new integrated assessment project on this very issue will be started at PIK in spring 2003. The assessment will cover economic aspects as well as potential side effects of various measures. In the economic module, the effects of investment decisions on technological innovation will be explicitly taken into account. Special emphasize will be put on the issue of uncertainty. Hereby we distinguish the uncertainty related to the Integrated Assessment modules, including the economic module, from the fact that no over-complex system can be fully captured by a model. Therefore, a scheme for the assessment of the ``residual'', the non-modelled part of the system, needs to be worked out. The scheme must be truly interdisciplinary, i.e. must be applicable to at least the natural science and the economic aspects. A scheme based on meta-principles like minimum persistence, ubiquity, or irreversibility of potential measures appears to be a promising candidate. An implementation of ubiquity as at present successfully operated in environmental chemistry may serve as a guideline [1]. Here, the best-known mechanism within a complex impact chain of potentially harmful chemicals, their transport, is captured by a reaction-diffusion mechanism [2]. begin{thebibliography}{0} bibitem{s} M. Scheringer, Persistence and spatial range as endpoints of an exposure-based assessment of organic chemicals. Environ. Sci. Technol. 30: 1652-1659 (1996). bibitem{h} H. Held, Robustness of spatial ranges of environmental chemicals with respect to model dimension, accepted for publication in Stoch. Environ. Res. Risk Assessment.

Two-Dimensional Stable Isotope Fractionation During Aerobic and Anaerobic Alkane Biodegradation and Implications for the Field

NASA Astrophysics Data System (ADS)

El Morris, Brandon; Suflita, Joseph M.; Richnow, Hans-Hermann

2010-05-01

Quantitatively, n-alkanes comprise a major portion of most crude oils. In petroliferous formations, it may be possible to relate the loss of these compounds to the levels of biodegradation occurring in situ [1]. Moreover, it is important to develop indicators of alkane degradation that may be used to monitor bioremediation of hydrocarbon-impacted environments. Desulfoglaeba alkanexedens and Pseudomonas putida GPo1 were used to determine if carbon and hydrogen stable isotope fractionation could differentiate between n-alkane degradation under anaerobic and aerobic conditions, respectively in the context of the Rayleigh equation model [2]. Bacterial cultures were sacrificed by acidification and headspace samples were analyzed for stable isotope composition using gas chromatography-isotope ratio mass spectrometry. Carbon enrichment factors (bulk) for anaerobic and aerobic biodegradation of hexane were -5.52 ± 0.2‰ and -4.34 ± 0.3‰, respectively. Hydrogen enrichment during hexane degradation was -43.14 ± 6.32‰ under sulfate-reducing conditions, and was too low for quantification during aerobiosis. Collectively, this indicates that the correlation between carbon and hydrogen stable isotope fractionation (may be used to help elucidate in situ microbial processes in oil reservoirs, and during intrinsic as well as engineered remediation efforts. References 1. Asif, M.; Grice, K.; Fazeelat, T., Assessment of petroleum biodegradation using stable hydrogen isotopes of individual saturated hydrocarbon and polycyclic aromatic hydrocarbon distributions in oils from the Upper Indus Basin, Pakistan. Organic Geochemistry 2009, 40, (3), 301-311. 2. Fischer, A.; Herklotz, I.; Herrmann, S.; Thullner, M.; Weelink, S. A. B.; Stams, A., J. M.; Schloemann, M.; Richnow, H.-H.; Vogt, C., Combined carbon and hydrogen isotope fractionation investigations for elucidating benzene biodegradation pathways. Environ. Sci. Technol. 2008, 42, 4356-4363.

EDITORIAL: Announcing the 2007 Measurement Science and Technology Outstanding Paper Awards

NASA Astrophysics Data System (ADS)

Foss, John; Dewhurst, Richard; Fujii, Kenichi; Regtien, Paul

2008-05-01

Since 1991, Measurement Science and Technology has awarded a Best Paper prize. The Editorial Board of this journal believes that such a prize is an opportunity to thank authors for submitting their work, and serves as an integral part of the on-going quality review of the journal. The current breadth of topical areas that are covered by MST has made it advisable to expand the recognition of excellent publications. Hence, since 2005 the Editorial Board have presented 'Outstanding Paper Awards' in four subject categories: Fluid Mechanics; Measurement Science; Precision Measurements; and Sensors and Sensing Systems. 2007 Award Winners—Fluid Mechanics An adaptive sampling and windowing interrogation method in PIV R Theunissen, F Scarano and M L Riethmuller von Karman Institute for Fluid Dynamics, Chaussée de Waterloo 72, 1640 Sint-Genesius Rode, Belgium and Department of Aerospace Engineering, Delft University of Technology, Delft, PO Box 5058, 2600 GB Delft, The Netherlands The co-authored paper [1] has been selected as the Outstanding Paper in Fluid Mechanics for 2007. This paper provides a strategy whereby the placement and the size of the interrogation regions are adapted to the image signal strength (seeding density) and the spatial variations of the velocity magnitudes. Two, quite distinct, test cases demonstrate the efficacy of their method: a shockwave- boundary layer interaction and an aircraft vortex wake. The Selection Committee—Drs T Fansler, J Foss, I Marusic, S Morris, K Okamoto and M Wernet—selected this paper from a strongly competitive shortlist of four candidates. Their selection process was influenced by the perceived utility of the contribution to the numerous investigators who utilize PIV methods. 2007 Award Winners—Measurement Science Broadband single cell impedance spectroscopy using maximum length sequences: theoretical analysis and practical considerations Tao Sun, Shady Gawad, Catia Bernabini, Nicolas G Green and Hywel Morgan Nanoscale Systems Integration Group, School of Electronics and Computer Science, University of Southampton, Southampton SO17 1BJ, UK The paper [2] describes a novel impedance spectroscopic measurement method for applications in the identification of biological cells. The frequency-dependent impedance is obtained in the frequency domain by applying a fast M-sequence transform (FMT), and a fast Fourier transform (FFT) in the time domain response. Using FMT, the evaluation takes place within a short timescale of the order of milliseconds. This technique is used in a microfluidic impedance cytometer, for the analysis of single biological cells in suspension. The theory of the technique is analysed in depth. It is then applied to an experimental system that characterizes the impedance spectrum of red blood cells within the microfluidic system. Measured spectra show good agreement with simulations. The paper has a short but excellent introduction, supported by a solid reference list of about 55 papers describing related work. Most of these papers are citations from 2000 onwards. This is followed by a detailed analysis of maximum length sequences and theory used for predictions of spectra. It then continues with a useful description of a cytometer that was used to confirm theoretical predictions of spectra. Results are at an early stage. The system is still under development, since there are issues arising from the fact that the particle flows during the acquisition of data, and is not static in the electric field as assumed by the model. Nevertheless, the paper possesses good clarity of the motivation behind the work, of the measurement techniques developed and of the potential relevance to applications in the life sciences. 2007 Award Winners—Precision Measurement Ultraprecision micro-CMM using a low force 3D touch probe A Küng, F Meli and R Thalmann Swiss Federal Office of Metrology (METAS), Lindenweg 50, CH-3003 Bern-Wabern, Switzerland The paper [3] describes a new three-dimensional coordinate measuring machine (CMM) developed for traceable measurement for small objects. The most sophisticated component of the system lies in the structure of its touch probe. It was designed based on a parallel kinematic mechanism with flexure hinges in order to minimize the moving mass and to ensure an isotropic low stiffness. This head features very weak probing forces, below 0.5 mN, and supports exchangeable probes down to 0.1 mm diameter, realizing a measurement without introducing any plastic deformation on the surface of the object. It was then combined with a highly accurate 90 mm × 90 mm × 38 mm air bearing stage with interferometric position measurement with no Abbe offset, achieving a typical reproducibility of 5 nm in measuring various shapes of the objects. In order to evaluate the contribution of the shape deviation of the probing sphere to the uncertainty, a new calibration method with three spheres has been developed in this work. In addition, a scanning measurement procedure was also implemented for fast measurement without any loss of accuracy, contributing to practical measurement for users. The selection committee members on precision measurement—Drs K Fujii and A Yacoot—and Editorial Board members Drs P Hauptmann, U Kaatze and M Player, selected this paper from a strongly competitive list of nine candidates. The paper opened a new way for achieving an unprecedented accuracy in coordinate metrology. 2007 Award Winners—Sensors and Sensing Systems Two-dimensional optical accelerometer based on commercial DVD pick-up head Chih-Liang Chu, Cha-Hao Lin and Kuang-Chao Fan Department of Mechanical Engineering, Southern Taiwan University of Technology, Tainan, Taiwan, Republic of China and Department of Mechanical Engineering, National Taiwan University, Taipei, Taiwan, Republic of China The authors describe in this paper [4] a 2D accelerometer that is based on a simple DVD pick-up head. It is a considerable extension of an earlier paper [5] dealing with a similar device but restricted to 1D only. In the awarded paper, not only is the extension to 2D presented, but also a thorough analysis of the system's performance is given. A clear description of the general concept is followed by the derivation of the intensity distribution on the four-quadrant photodetector. In the next section, the design of the mechanical part is detailed, including a FEM analysis for obtaining optimal performance characteristics in terms of resonance frequency, sensitivity and range. The system is extensively tested, and the paper presents a useful selection of the measurement data in graphical and numerical format. Altogether, theory, experimental and measurement results are presented in a clear and well balanced way, and illustrated with neat graphics. A missing uncertainty analysis is the only deficiency in this otherwise excellent paper. A sequel to this paper from the same authors appeared a few issues later [6], presenting the DVD head as a nanoscale touch trigger probe. Both papers belong to the top 60 most downloaded papers in the 2007 volume. The Outstanding Paper Awards, comprising a cash honorarium and certificate, will be presented to the authors of the winning papers at suitable venues in the near future. The Editorial Board would like to congratulate the winning authors and would like to encourage all researchers to think of Measurement Science and Technology as the home for your best submissions. References [1] Theunissen R, Scarano F and Riethmuller M L 2007 An adaptive sampling and windowing interrogation method in PIV Meas. Sci. Technol. 18 275-87 [2] Sun T, Gawad S, Bernabini C, Green N G and Morgan H 2007 Broadband single cell impedance spectroscopy using maximum length sequences: theoretical analysis and practical considerations Meas. Sci. Technol. 18 2859-68 [3] Küng A, Meli F and Thalmann R 2007 Ultraprecision micro-CMM using a low force 3D touch probe Meas. Sci. Technol. 18 319-27 [4] Chu C-L, Lin C-H and Fan K-C 2007 Two-dimensional optical accelerometer based on commercial DVD pick-up head Meas. Sci. Technol. 18 265-74 [5] Chu C-L and Lin C-H 2005 Development of an optical accelerometer with a DVD pick-up head Meas. Sci. Technol. 16 2498-502 [6] Chu C-L and Chiu C-Y 2007 Development of a low-cost nanoscale touch trigger probe based on two commercial DVD pick-up heads Meas. Sci. Technol. 18 1831-42

Demonstrating the Value of Fine-resolution Optical Data for Minimising Aliasing Impacts on Biogeochemical Models of Surface Waters

NASA Astrophysics Data System (ADS)

Chappell, N. A.; Jones, T.; Young, P.; Krishnaswamy, J.

2015-12-01

There is increasing awareness that under-sampling may have resulted in the omission of important physicochemical information present in water quality signatures of surface waters - thereby affecting interpretation of biogeochemical processes. For dissolved organic carbon (DOC) and nitrogen this under-sampling can now be avoided using UV-visible spectroscopy measured in-situ and continuously at a fine-resolution e.g. 15 minutes ("real time"). Few methods are available to extract biogeochemical process information directly from such high-frequency data. Jones, Chappell & Tych (2014 Environ Sci Technol: 13289-97) developed one such method using optically-derived DOC data based upon a sophisticated time-series modelling tool. Within this presentation we extend the methodology to quantify the minimum sampling interval required to avoid distortion of model structures and parameters that describe fundamental biogeochemical processes. This shifting of parameters which results from under-sampling is called "aliasing". We demonstrate that storm dynamics at a variety of sites dominate over diurnal and seasonal changes and that these must be characterised by sampling that may be sub-hourly to avoid aliasing. This is considerably shorter than that used by other water quality studies examining aliasing (e.g. Kirchner 2005 Phys Rev: 069902). The modelling approach presented is being developed into a generic tool to calculate the minimum sampling for water quality monitoring in systems driven primarily by hydrology. This is illustrated with fine-resolution, optical data from watersheds in temperate Europe through to the humid tropics.

Capture efficiency of cooking-related fine and ultrafine particles by residential exhaust hoods.

PubMed

Lunden, M M; Delp, W W; Singer, B C

2015-02-01

Effective exhaust hoods can mitigate the indoor air quality impacts of pollutant emissions from residential cooking. This study reports capture efficiencies (CE) measured for cooking-generated particles for scripted cooking procedures in a 121-m3 chamber with kitchenette. CEs also were measured for burner produced CO2 during cooking and separately for pots and pans containing water. The study used four exhaust hoods previously tested by Delp and Singer (Environ. Sci. Technol., 2012, 46, 6167-6173). For pan-frying a hamburger over medium heat on the back burner, CEs for particles were similar to those for burner produced CO2 and mostly above 80%. For stir-frying green beans in a wok (high heat, front burner), CEs for burner CO2 during cooking varied by hood and airflow: CEs were 34-38% for low (51-68 l/s) and 54-72% for high (109-138 l/s) settings. CEs for 0.3-2.0 μm particles during front burner stir-frying were 3-11% on low and 16-70% on high settings. Results indicate that CEs measured for burner CO2 are not predictive of CEs of cooking-generated particles under all conditions, but they may be suitable to identify devices with CEs above 80% both for burner combustion products and for cooking-related particles. Published 2014. This article is a U.S. Government work and is in the public domain in the USA.

Using Scenarios to Design Complex Technology-Enhanced Learning Environments

ERIC Educational Resources Information Center

de Jong, Ton; Weinberger, Armin; Girault, Isabelle; Kluge, Anders; Lazonder, Ard W.; Pedaste, Margus; Ludvigsen, Sten; Ney, Muriel; Wasson, Barbara; Wichmann, Astrid; Geraedts, Caspar; Giemza, Adam; Hovardas, Tasos; Julien, Rachel; van Joolingen, Wouter R.; Lejeune, Anne; Manoli, Constantinos C.; Matteman, Yuri; Sarapuu, Tago; Verkade, Alex; Vold, Vibeke; Zacharia, Zacharias C.

2012-01-01

Science Created by You (SCY) learning environments are computer-based environments in which students learn about science topics in the context of addressing a socio-scientific problem. Along their way to a solution for this problem students produce many types of intermediate products or learning objects. SCY learning environments center the entire…

THE EFFECT OF AMOUNT OF CRUDE OIL ON EXTENT OF ITS BIODEGRADATION IN OPEN WATER- AND SANDY BEACH- LABORATORY SIMULATIONS

EPA Science Inventory

Lepo, J.E., C. R. Cripe, J.L. Kavanaugh, S. Zhang and G.P. Norton. 2003. Effect of Amount of Crude Oil on Extent of Its Biodegradation in Open Water- and Sandy Beach-Laboratory Simulations. Environ. Technol. 24(10):1291-1302. (ERL,GB 1109).

We examined the biodegradation ...

Comparison of different measurement methods for transmittance haze

NASA Astrophysics Data System (ADS)

Yu, Hsueh-Ling; Hsaio, Chin-Chai

2009-08-01

Transmittance haze is increasingly important to the LCD and solar cell industry. Most commercial haze measurement instruments are designed according to the method recommended in the documentary standards like ASTM D 1003 (ASTM 2003 Standard Test Method for Haze and Luminous Transmittance of Transparent Plastics), JIS K 7361 (JIS 1997 Plastics—Determination of the Total Luminous Transmittance of Transparent Materials—Part 1: Single Beam Instrument) and ISO 14782 (ISO 1997 Plastics—Determination of Haze of Transparent Materials). To improve the measurement accuracy of the current standards, a new apparatus was designed by the Center for Measurement Standards (Yu et al 2006 Meas. Sci. Technol. 17 N29-36). Besides the methods mentioned above, a double-beam method is used in the design of some instruments. There are discrepancies between the various methods. But no matter which method is used, a white standard is always needed. This paper compares the measurement results from different methods, presents the effect of the white standard, and analyses the measurement uncertainty.

FPGA-based photon-counting phase-modulation fluorometer and a brief comparison with that operated in a pulsed-excitation mode

NASA Astrophysics Data System (ADS)

Iwata, Tetsuo; Taga, Takanori; Mizuno, Takahiko

2018-02-01

We have constructed a high-efficiency, photon-counting phase-modulation fluorometer (PC-PMF) using a field-programmable gate array, which is a modified version of the photon-counting fluorometer (PCF) that works in a pulsed-excitation mode (Iwata and Mizuno in Meas Sci Technol 28:075501, 2017). The common working principle for both is the simultaneous detection of the photoelectron pulse train, which covers 64 ns with a 1.0-ns resolution time (1.0 ns/channel). The signal-gathering efficiency was improved more than 100 times over that of conventional time-correlated single-photon-counting at the expense of resolution time depending on the number of channels. The system dead time for building a histogram was eliminated, markedly shortening the measurement time for fluorescent samples with moderately high quantum yields. We describe the PC-PMF and make a brief comparison with the pulsed-excitation PCF in precision, demonstrating the potential advantage of PC-PMF.

Current profile redistribution driven by neutral beam injection in a reversed-field pinch

NASA Astrophysics Data System (ADS)

Parke, E.; Anderson, J. K.; Brower, D. L.; Den Hartog, D. J.; Ding, W. X.; Johnson, C. A.; Lin, L.

2016-05-01

Neutral beam injection in reversed-field pinch (RFP) plasmas on the Madison Symmetric Torus [Dexter et al., Fusion Sci. Technol. 19, 131 (1991)] drives current redistribution with increased on-axis current density but negligible net current drive. Internal fluctuations correlated with tearing modes are observed on multiple diagnostics; the behavior of tearing mode correlated structures is consistent with flattening of the safety factor profile. The first application of a parametrized model for island flattening to temperature fluctuations in an RFP allows inferrence of rational surface locations for multiple tearing modes. The m = 1, n = 6 mode is observed to shift inward by 1.1 ± 0.6 cm with neutral beam injection. Tearing mode rational surface measurements provide a strong constraint for equilibrium reconstruction, with an estimated reduction of q0 by 5% and an increase in on-axis current density of 8% ± 5%. The inferred on-axis current drive is consistent with estimates of fast ion density using TRANSP [Goldston et al., J. Comput. Phys. 43, 61 (1981)].

Theoretical analysis of field emission from a metal diamond cold cathode emitter

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lerner, P.; Cutler, P.H.; Miskovsky, N.M.

Recently, Geis {ital et al.} [J. Vac. Sci. Technol. B {bold 14}, 2060 (1996)] proposed a cold cathode emitter based on a Spindt-type design using a diamond film doped by substitutional nitrogen. The device is characterized by high field emission currents at very low power. Two properties, the rough surface of the metallic injector and the negative electron affinity of the (111) surface of the diamond are essential for its operation. We present a first consistent quantitative theory of the operation of a Geis{endash}Spindt diamond field emitter. Its essential features are predicated on nearly {ital zero-field conditions} in the diamondmore » beyond the depletion layer, {ital quasiballistic transport} in the conduction band, and applicability of a modified {ital Fowler{endash}Nordheim equation} to the transmission of electrons through the Schottky barrier at the metal-diamond interface. Calculated results are in good qualitative and quantitative agreement with the experimental results of Geis {ital et al.} {copyright} {ital 1997 American Vacuum Society.}« less

Improvement of the ESR detection of irradiated food containing cellulose employing a simple extraction method

NASA Astrophysics Data System (ADS)

Delincée, Henry; Soika, Christiane

2002-03-01

Fruit may be irradiated at rather low doses, below 1 kGy in combination treatments or for quarantine purposes. To improve the ESR detection sensitivity of irradiated fruit de Jesus et al. (Int. J. Food Sci. Technol. 34 (1999) 173.) proposed extracting the fruit pulp with 80% ethanol and measuring the residue with ESR using low power (0.25 mW) for detection of 'cellulosic' radicals. An improvement in ESR sensitivity using the extraction procedure could be confirmed in this paper for strawberries and papayas. In most cases, a radiation dose of 0.5 kGy could be detected in both fruits even after 2-3 weeks storage. In addition, some herbs and spices were also tested, but only for a few of them the ESR detection of the 'cellulosic' signal was improved by previous alcoholic extraction. As an alternative to ESR measurements, other detection methods like DNA Comet Assay and thermoluminescence were also tested.

Exploring the limits of case-to-capsule ratio, pulse length, and picket energy for symmetric hohlraum drive on the National Ignition Facility Laser

NASA Astrophysics Data System (ADS)

Callahan, D. A.; Hurricane, O. A.; Ralph, J. E.; Thomas, C. A.; Baker, K. L.; Benedetti, L. R.; Berzak Hopkins, L. F.; Casey, D. T.; Chapman, T.; Czajka, C. E.; Dewald, E. L.; Divol, L.; Döppner, T.; Hinkel, D. E.; Hohenberger, M.; Jarrott, L. C.; Khan, S. F.; Kritcher, A. L.; Landen, O. L.; LePape, S.; MacLaren, S. A.; Masse, L. P.; Meezan, N. B.; Pak, A. E.; Salmonson, J. D.; Woods, D. T.; Izumi, N.; Ma, T.; Mariscal, D. A.; Nagel, S. R.; Kline, J. L.; Kyrala, G. A.; Loomis, E. N.; Yi, S. A.; Zylstra, A. B.; Batha, S. H.

2018-05-01

We present a data-based model for low mode asymmetry in low gas-fill hohlraum experiments on the National Ignition Facility {NIF [Moses et al., Fusion Sci. Technol. 69, 1 (2016)]} laser. This model is based on the hypothesis that the asymmetry in these low fill hohlraums is dominated by the hydrodynamics of the expanding, low density, high-Z (gold or uranium) "bubble," which occurs where the intense outer cone laser beams hit the high-Z hohlraum wall. We developed a simple model which states that the implosion symmetry becomes more oblate as the high-Z bubble size becomes large compared to the hohlraum radius or the capsule size becomes large compared to the hohlraum radius. This simple model captures the trends that we see in data that span much of the parameter space of interest for NIF ignition experiments. We are now using this model as a constraint on new designs for experiments on the NIF.

Growth anisotropy effect of bulk high temperature superconductors on the levitation performance in the applied magnetic field

NASA Astrophysics Data System (ADS)

Zheng, J.; Liao, X. L.; Jing, H. L.; Deng, Z. G.; Yen, F.; Wang, S. Y.; Wang, J. S.

2013-10-01

Growth anisotropies of bulk high temperature superconductors (HTSCs) fabricated by a top-seeded melt texture growth process, that is, different pinning effect in the growth sectors (GSs) and growth sector boundaries (GSBs), possess effect on the macro flux trapping and levitation performance of bulk HTSCs. Previous work (Physics Procedia, 36 (2012) 1043) has found that the bulk HTSC array with aligned GSB pattern (AGSBP) exhibits better capability for levitation and suppression of levitation force decay above a permanent magnet guideway (PMG) compared with misaligned GSB pattern (MGSBP). In this paper, we further examine this growth anisotropy effect on the maglev performance of a double-layer bulk HTSC. In contrast to reported trapped flux cases (Supercond. Sci. Technol. 19 (2006) S466), the two superposed bulk HTSCs with same AGSBP with PMG are found to show better maglev performance. These series of results are helpful and support a new way for the performance optimization of present HTS maglev systems.

A mathematical analysis of the ABCD criteria for diagnosing malignant melanoma

NASA Astrophysics Data System (ADS)

Lee, Hyunju; Kwon, Kiwoon

2017-03-01

The medical community currently employs the ABCD (asymmetry, border irregularity, color variegation, and diameter of the lesion) criteria in the early diagnosis of a malignant melanoma. Although many image segmentation and classification methods are used to analyze the ABCD criteria, it is rare to see a study containing mathematical justification of the parameters that are used to quantify the ABCD criteria. In this paper, we suggest new parameters to assess asymmetry, border irregularity, and color variegation, and explain the mathematical meaning of the parameters. The suggested parameters are then tested with 24 skin samples. The parameters suggested for the 24 skin samples are displayed in three-dimensional coordinates and are compared to those presented in other studies (Ercal et al 1994 IEEE Trans. Biomed. Eng. 41 837-45, Cheerla and Frazier 2014 Int. J. Innovative Res. Sci., Eng. Technol. 3 9164-83) in terms of Pearson correlation coefficient and classification accuracy in determining the malignancy of the lesions.

Amplification of terahertz pulses in gases beyond thermodynamic equilibrium

NASA Astrophysics Data System (ADS)

Schwaab, G. W.; Schroeck, K.; Havenith, M.

2007-03-01

In Ebbinghaus [Plasma Sources Sci. Technol. 15, 72 (2006)] we reported terahertz time-domain spectroscopy in a plasma at low pressure, we observed a simultaneous absorption and amplification process within each single rotational transition. Here we show that this observation is a direct consequence of the short interaction time of the pulsed terahertz radiation with the plasma, which is shorter than the average collision time between the molecules. Thus, during the measurement time the molecular states may be considered entangled. Solution of the time-dependent Schrödinger equation yields a linear term that may be neglected for long observation times, large frequencies, or nonentangled states. We determine the restrictions for the observation of this effect and calculate the spectrum of a simple diatomic molecule. Using this model we are able to explain the spectral features showing a change from emission to absorption as observed previously. In addition we find that the amplification and absorption do not follow the typical Lambert-Beer exponential law but an approximate square law.

Phenomenological scattering-rate model for the simulation of the current density and emission power in mid-infrared quantum cascade lasers

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kurlov, S. S.; Institute of Semiconductor Physics, National Academy of Sciences, pr. Nauki 45, Kiev-03028; Flores, Y. V.

2016-04-07

A phenomenological scattering-rate model introduced for terahertz quantum cascade lasers (QCLs) [Schrottke et al., Semicond. Sci. Technol. 25, 045025 (2010)] is extended to mid-infrared (MIR) QCLs by including the energy dependence of the intersubband scattering rates for energies higher than the longitudinal optical phonon energy. This energy dependence is obtained from a phenomenological fit of the intersubband scattering rates based on published lifetimes of a number of MIR QCLs. In our approach, the total intersubband scattering rate is written as the product of the exchange integral for the squared moduli of the envelope functions and a phenomenological factor that dependsmore » only on the transition energy. Using the model to calculate scattering rates and imposing periodical boundary conditions on the current density, we find a good agreement with low-temperature data for current-voltage, power-current, and energy-photon flux characteristics for a QCL emitting at 5.2 μm.« less

Numerical Simulation for Predicting Fatigue Damage Progress in Notched CFRP Laminates by Using Cohesive Elements

NASA Astrophysics Data System (ADS)

Okabe, Tomonaga; Yashiro, Shigeki

This study proposes the cohesive zone model (CZM) for predicting fatigue damage growth in notched carbon-fiber-reinforced composite plastic (CFRP) cross-ply laminates. In this model, damage growth in the fracture process of cohesive elements due to cyclic loading is represented by the conventional damage mechanics model. We preliminarily investigated whether this model can appropriately express fatigue damage growth for a circular crack embedded in isotropic solid material. This investigation demonstrated that this model could reproduce the results with the well-established fracture mechanics model plus the Paris' law by tuning adjustable parameters. We then numerically investigated the damage process in notched CFRP cross-ply laminates under tensile cyclic loading and compared the predicted damage patterns with those in experiments reported by Spearing et al. (Compos. Sci. Technol. 1992). The predicted damage patterns agreed with the experiment results, which exhibited the extension of multiple types of damage (e.g., splits, transverse cracks and delaminations) near the notches.

Summary: Update to ASTM guide E 1523 to charge control and charge referencing techniques in x-ray photoelectron spectroscopy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Baer, D.R.

2005-05-01

An updated version of the American Society for Testing and Materials (ASTM) guide E 1523 to the methods to charge control and charge referencing techniques in x-ray photoelectron spectroscopy has been released by ASTM [Annual Book of ASTM Standards Surface Analysis (American Society for Testing and Materials, West Conshohocken, PA, 2004), Vol. 03.06]. The guide is meant to acquaint x-ray photoelectron spectroscopy (XPS) users with the various charge control and charge referencing techniques that are and have been used in the acquisition and interpretation of XPS data from surfaces of insulating specimens. The current guide has been expanded to includemore » new references as well as recommendations for reporting information on charge control and charge referencing. The previous version of the document had been published in 1997 [D. R. Baer and K. D. Bomben, J. Vac. Sci. Technol. A 16, 754 (1998)].« less

Responding to Students' Learning Preferences in Chemistry

NASA Astrophysics Data System (ADS)

Lewthwaite, Brian; Wiebe, Rick

2014-04-01

This paper reports on a teacher's and his students' responsiveness to a new tetrahedral-oriented (Mahaffy in J Chem Educ 83(1):49-55, 2006) curriculum requiring more discursive classroom practices in the teaching of chemistry. In this instrumental case study, we identify the intentions of this learner-centered curriculum and a teacher's development in response to this curriculum. We also explore the tensions this teacher experiences as students subsequently respond to his adjusted teaching. We use a Chemistry Teacher Inventory (Lewthwaite and Wiebe in Res Sci Educ 40(11):667-689, 2011; Lewthwaite and Wiebe in Can J Math Sci Technol Educ 12(1):36-61, 2012; Lewthwaite in Chem Educ Res Pract. doi:10.1039/C3RP00122A, 2014) to assist the teacher in monitoring how he teaches and how he would like to improve his teaching. We also use a student form of the instrument, the Chemistry Classroom Inventory and Classroom Observation Protocol (Lewthwaite and Wiebe 2011) to verify the teacher's teaching and perception of student preferences for his teaching especially in terms of the discursive processes the curriculum encourages. By so doing, the teacher is able to use both sets of data as a foundation for critical reflection and work towards resolution of the incongruence in data arising from students' preferred learning orientations and his teaching aspirations. Implications of this study in regards to the authority of students' voice in triggering teachers' pedagogical change and the adjustments in `teachering' and `studenting' required by such curricula are considered.

Normalization and extension of single-collector efficiency correlation equation

NASA Astrophysics Data System (ADS)

Messina, Francesca; Marchisio, Daniele; Sethi, Rajandrea

2015-04-01

The colloidal transport and deposition are important phenomena involved in many engineering problems. In the environmental engineering field the use of micro- and nano-scale zerovalent iron (M-NZVI) is one of the most promising technologies for groundwater remediation. Colloid deposition is normally studied from a micro scale point of view and the results are then implemented in macro scale models that are used to design field-scale applications. The single collector efficiency concept predicts particles deposition onto a single grain of a complex porous medium in terms of probability that an approaching particle would be retained on the solid grain. In literature, many different approaches and equations exist to predict it, but most of them fail under specific conditions (e.g. very small or very big particle size and very low fluid velocity) because they predict efficiency values exceeding unity. By analysing particle fluxes and deposition mechanisms and performing a mass balance on the entire domain, the traditional definition of efficiency was reformulated and a novel total flux normalized correlation equation is proposed for predicting single-collector efficiency under a broad range of parameters. It has been formulated starting from a combination of Eulerian and Lagrangian numerical simulations, performed under Smoluchowski-Levich conditions, in a geometry which consists of a sphere enveloped by a control volume. In order to guarantee the independence of each term, the correlation equation is derived through a rigorous hierarchical parameter estimation process, accounting for single and mutual interacting transport mechanisms. The correlation equation provides efficiency values lower than one over a wide range of parameters and is valid both for point and finite-size particles. A reduced form is also proposed by elimination of the less relevant terms. References 1. Yao, K. M.; Habibian, M. M.; Omelia, C. R., Water and Waste Water Filtration - Concepts and Applications. Environ Sci Technol 1971, 5, (11), 1105-&. 2. Tufenkji, N., and M. Elimelech, Correlation equation for predicting single-collector efficiency in physicochemical filtration in saturated porous media. Environmental Science & Technology 2004 38(2):529-536. 3. Boccardo, G.; Marchisio, D. L.; Sethi, R., Microscale simulation of particle deposition in porous media. J Colloid Interface Sci 2014, 417, 227-37

DOE Office of Scientific and Technical Information (OSTI.GOV)

Metzler, Dominik; Li, Chen; Engelmann, Sebastian

With the increasing interest in establishing directional etching methods capable of atomic scale resolution for fabricating highly scaled electronic devices, the need for development and characterization of atomic layer etching (ALE) processes, or generally etch processes with atomic layer precision, is growing. In this work, a flux-controlled cyclic plasma process is used for etching of SiO 2 and Si at the Angstrom-level. This is based on steady-state Ar plasma, with periodic, precise injection of a fluorocarbon (FC) precursor (C 4F 8 and CHF 3), and synchronized, plasma-based Ar+ ion bombardment [D. Metzler et al., J Vac Sci Technol A 32,more » 020603 (2014), and D. Metzler et al., J Vac Sci Technol A 34, 01B101 (2016)]. For low energy Ar+ ion bombardment conditions, physical sputter rates are minimized, whereas material can be etched when FC reactants are present at the surface. This cyclic approach offers a large parameter space for process optimization. Etch depth per cycle, removal rates, and self-limitation of removal, along with material dependence of these aspects, were examined as a function of FC surface coverage, ion energy, and etch step length using in situ real time ellipsometry. The deposited FC thickness per cycle is found to have a strong impact on etch depth per cycle of SiO 2 and Si, but is limited with regard to control over material etching selectivity. Ion energy over the 20 to 30 eV range strongly impacts material selectivity. The choice of precursor can have a significant impact on the surface chemistry and chemically enhanced etching. CHF 3 has a lower FC deposition yield for both SiO 2 and Si, and also exhibits a strong substrate dependence of FC deposition yield, in contrast to C4F 8. The thickness of deposited FC layers using CHF 3 is found to be greater for Si than for SiO 2. X-ray photoelectron spectroscopy was used to study surface chemistry. When thicker FC films of 11 Å are employed, strong changes of FC film chemistry during a cycle are seen whereas the chemical state of the substrate varies much less. On the other hand, for FC film deposition of 5 Å for each cycle, strong substrate surface chemical changes are seen during an etching cycle. The nature of this cyclic etching with periodic deposition of thin FC films differs significantly from conventional etching with steady-state FC layers since surface conditions change strongly throughout each cycle.« less

A thermal desorption mass spectrometer for freshly nucleated secondary aerosol particles

NASA Astrophysics Data System (ADS)

Held, A.; Gonser, S. G.

2012-04-01

Secondary aerosol formation in the atmosphere is observed in a large variety of locations worldwide, introducing new particles to the atmosphere which can grow to sizes relevant for health and climate effects of aerosols. The chemical reactions leading to atmospheric secondary aerosol formation are not yet fully understood. At the same time, analyzing the chemical composition of freshly nucleated particles is still a challenging task. We are currently finishing the development of a field portable aerosol mass spectrometer for nucleation particles with diameters smaller than 30 nm. This instrument consists of a custom-built aerosol sizing and collection unit coupled to a time-of-flight mass spectrometer (TOF-MS). The aerosol sizing and collection unit is composed of three major parts: (1) a unipolar corona aerosol charger, (2) a radial differential mobility analyzer (rDMA) for aerosol size separation, and (3) an electrostatic precipitator for aerosol collection. After collection, the aerosol sample is thermally desorbed, and the resulting gas sample is transferred to the TOF-MS for chemical analysis. The unipolar charger is based on corona discharge from carbon fibres (e.g. Han et al., 2008). This design allows efficient charging at voltages below 2 kV, thus eliminating the potential for ozone production which would interfere with the collected aerosol. With the current configuration the extrinsic charging efficiency for 20 nm particles is 32 %. The compact radial DMA similar to the design of Zhang et al. (1995) is optimized for a diameter range from 1 nm to 100 nm. Preliminary tests show that monodisperse aerosol samples (geometric standard deviation of 1.09) at 10 nm, 20 nm, and 30 nm can easily be separated from the ambient polydisperse aerosol population. Finally, the size-segregated aerosol sample is collected on a high-voltage biased metal filament. The collected sample is protected from contamination using a He sheath counterflow. Resistive heating of the filament allows temperature-controlled desorption of compounds of different volatility. We will present preliminary characterization experiments of the aerosol sizing and collection unit coupled to the mass spectrometer. Funding by the German Research Foundation (DFG) under grant DFG HE5214/3-1 is gratefully acknowledged. Han, B., Kim, H.J., Kim, Y.J., and Sioutas, C. (2008) Unipolar charging of ultrafine particles using carbon fiber ionizers. Aerosol Sci. Technol, 42, 793-800. Zhang, S.-H., Akutsu, Y., Russell, L.M., Flagan, R.C., and Seinfeld, J.H. (1995) Radial Differential Mobility Analyzer. Aerosol Sci. Technol, 23, 357-372.

Characterizing fluorocarbon assisted atomic layer etching of Si using cyclic Ar/C4F8 and Ar/CHF3 plasma

NASA Astrophysics Data System (ADS)

Metzler, Dominik; Li, Chen; Engelmann, Sebastian; Bruce, Robert L.; Joseph, Eric A.; Oehrlein, Gottlieb S.

2017-02-01

With the increasing interest in establishing directional etching methods capable of atomic scale resolution for fabricating highly scaled electronic devices, the need for development and characterization of atomic layer etching processes, or generally etch processes with atomic layer precision, is growing. In this work, a flux-controlled cyclic plasma process is used for etching of SiO2 and Si at the Angstrom-level. This is based on steady-state Ar plasma, with periodic, precise injection of a fluorocarbon (FC) precursor (C4F8 and CHF3) and synchronized, plasma-based Ar+ ion bombardment [D. Metzler et al., J. Vac. Sci. Technol., A 32, 020603 (2014) and D. Metzler et al., J. Vac. Sci. Technol., A 34, 01B101 (2016)]. For low energy Ar+ ion bombardment conditions, physical sputter rates are minimized, whereas material can be etched when FC reactants are present at the surface. This cyclic approach offers a large parameter space for process optimization. Etch depth per cycle, removal rates, and self-limitation of removal, along with material dependence of these aspects, were examined as a function of FC surface coverage, ion energy, and etch step length using in situ real time ellipsometry. The deposited FC thickness per cycle is found to have a strong impact on etch depth per cycle of SiO2 and Si but is limited with regard to control over material etching selectivity. Ion energy over the 20-30 eV range strongly impacts material selectivity. The choice of precursor can have a significant impact on the surface chemistry and chemically enhanced etching. CHF3 has a lower FC deposition yield for both SiO2 and Si and also exhibits a strong substrate dependence of FC deposition yield, in contrast to C4F8. The thickness of deposited FC layers using CHF3 is found to be greater for Si than for SiO2. X-ray photoelectron spectroscopy was used to study surface chemistry. When thicker FC films of 11 Å are employed, strong changes of FC film chemistry during a cycle are seen whereas the chemical state of the substrate varies much less. On the other hand, for FC film deposition of 5 Å for each cycle, strong substrate surface chemical changes are seen during an etching cycle. The nature of this cyclic etching with periodic deposition of thin FC films differs significantly from conventional etching with steady-state FC layers since surface conditions change strongly throughout each cycle.

LLCySA: Making Sense of Cyberspace

DTIC Science & Technology

2014-01-01

data center. His other activities include the development of immersive 3D environments leveraging video- game technology to provide a multiplayer ...exploring data-driven approaches to network protection. Imagine a cyber analyst navigating a three-dimen- sional (3D) game , walking down virtual office...because of information overload. One approach to this challenge leverages technol- ogy utilized in the 3D gaming industry. The video- game medium

Position-specific isotope modeling of organic micropollutants transformations through different reaction pathways

NASA Astrophysics Data System (ADS)

Jin, Biao; Rolle, Massimo

2016-04-01

Organic compounds are produced in vast quantities for industrial and agricultural use, as well as for human and animal healthcare [1]. These chemicals and their metabolites are frequently detected at trace levels in fresh water environments where they undergo degradation via different reaction pathways. Compound specific stable isotope analysis (CSIA) is a valuable tool to identify such degradation pathways in different environmental systems. Recent advances in analytical techniques have promoted the fast development and implementation of multi-element CSIA. However, quantitative frameworks to evaluate multi-element stable isotope data and incorporating mechanistic information on the degradation processes [2,3] are still lacking. In this study we propose a mechanism-based modeling approach to simultaneously evaluate concentration as well as bulk and position-specific multi-element isotope evolution during the transformation of organic micropollutants. The model explicitly simulates position-specific isotopologues for those atoms that experience isotope effects and, thereby, provides a mechanistic description of isotope fractionation occurring at different molecular positions. We validate the proposed approach with the concentration and multi-element isotope data of three selected organic micropollutants: dichlorobenzamide (BAM), isoproturon (IPU) and diclofenac (DCF). The model precisely captures the dual element isotope trends characteristic of different reaction pathways and their range of variation consistent with observed multi-element (C, N) bulk isotope fractionation. The proposed approach can also be used as a tool to explore transformation pathways in scenarios for which position-specific isotope data are not yet available. [1] Schwarzenbach, R.P., Egli, T., Hofstetter, T.B., von Gunten, U., Wehrli, B., 2010. Global Water Pollution and Human Health. Annu. Rev. Environ. Resour. doi:10.1146/annurev-environ-100809-125342. [2] Jin, B., Haderlein, S.B., Rolle, M., 2013. Integrated carbon and chlorine isotope modeling: Applications to chlorinated aliphatic hydrocarbons dechlorination. Environ. Sci. Technol. 47, 1443-1451. doi:10.1021/es304053h. [3] Jin, B., Rolle, M., 2014. Mechanistic approach to multi-element isotope modeling of organic contaminant degradation. Chemosphere 95, 131-139. doi:10.1016/j.chemosphere.2013.08.050.

Evaluation of Microlon and Technol-G : final report.

DOT National Transportation Integrated Search

1982-01-01

An evaluation was made of the cost-effectiveness of the automotive products Microlon, an engine treatment consisting of Teflon suspended in a solvent, and Technol-G, a gasoline treating additive consisting of a blend of aliphatic and aromatic distill...

Outpatient spinal cord injury rehabilitation: managing costs and funding in a changing health care environment.

PubMed

Riis, V; Verrier, M C

2007-10-15

To examine the literature describing the cost of outpatient rehabilitation for patients with spinal cord injury (SCI) as well as the effect of funding type on cost and outcome. A SCI rehabilitation planning and funding model is presented that calls for structured assessment of the client's economic environment, with follow through to promote full access to funding for rehabilitation plans. Literature review of specific outpatient rehabilitation intervention costs and effect of funding type, followed by development of a funding model to improve access to available funding for SCI rehabilitation. There is insufficient economic data to draw conclusions about the relationship between an individual's rehabilitation needs and access to appropriate funding for outpatient rehabilitation. Consequently, health providers and payers need to adopt an approach that will improve consistency of payment decisions and access to necessary funding for rehabilitation. A model for a more formal approach to: (a) Assessment of a client's economic environment; (b) use of evidence-based SCI rehabilitation; and (c) use of available financial resources should promote better access to appropriate rehabilitation following SCI.

Stable Fe isotope fractionation during anaerobic microbial dissimilatory iron reduction at low pH

NASA Astrophysics Data System (ADS)

Chanda, P.; Amenabar, M. J.; Boyd, E. S.; Beard, B. L.; Johnson, C.

2017-12-01

In low-temperature anaerobic environments microbial dissimilatory iron reduction (DIR) plays an important role in Fe cycling. At neutral pH, sorption of aqueous Fe(II) (Fe(II)aq, produced by DIR) catalyzes isotopic exchange between Fe(II) and solid Fe(III), producing 56Fe/54Fe fractionations on the order of 3‰ during DIR[1,2,3]. At low pH, however, the absence of sorbed Fe(II) produces only limited abiologic isotopic exchange[4]. Here we investigated the scope of isotopic exchange between Fe(II)aq and ferric (hydr)oxides (ferrihydrite and goethite) and the associated stable Fe isotope fractionation during DIR by Acidianus strain DS80 at pH 3.0 and 80°C[5]. Over 19 days, 13% reduction of both minerals via microbial DIR was observed. The δ56Fe values of the fluid varied from -2.31 to -1.63‰ (ferrihydrite) and -0.45 to 0.02‰ (goethite). Partial leaching of bulk solid from each reactor with dilute HCl showed no sorption of Fe(II), and the surface layers of the solids were composed of Fe(III) with high δ56Fe values (ferrihydrite: 0.20 to 0.48‰ and goethite: 1.20 to 1.30‰). These results contrast with the lack of Fe isotope exchange in abiologic low-pH systems and indicate a key role for biology in catalyzing Fe isotope exchange between Fe(II)aq and Fe(III) solids, despite the absence of sorbed Fe(II). The estimated fractionation factor (ΔFeFe(III) -Fe(II)aq 2.6‰) from leaching of ferrihydrite is similar to the abiologic equilibrium fractionation factor ( 3.0‰)[3]. The fractionation factor (ΔFeFe(III) -Fe(II)aq 2.0‰) for goethite is higher than the abiologic fractionation factor ( 1.05‰)[2], but is consistent with the previously proposed "distorted surface layer" of goethite produced during the exchange with Fe(II)aq at neutral pH[1]. This study indicates that significant variations in Fe isotope compositions may be produced in low-pH environments where biological cycling of Fe occurs, in contrast to the expected lack of isotopic fractionation in low-pH abiologic systems, and such results bear on the search for biosignatures in Mars and Mars-analog settings. [1] Crosby et al., 2007 Geobiol. 5, 169-189 [2] Beard et al., 2010 Earth Planet. Sci. Lett. 295, 241-250 [3] Wu et al., 2011 Environ. Sci. Technol. 45, 1847-1852 [4] Reddy et al., 2015 Chem. Geol. 397, 118-127 [5] Amenabar et al., 2017 Nat. Geosci. In press

Model analysis of secondary organic aerosol formation by glyoxal in laboratory studies: the case for photoenhanced chemistry.

PubMed

Sumner, Andrew J; Woo, Joseph L; McNeill, V Faye

2014-10-21

The reactive uptake of glyoxal by atmospheric aerosols is believed to be a significant source of secondary organic aerosol (SOA). Several recent laboratory studies have been performed with the goal of characterizing this process, but questions remain regarding the effects of photochemistry on SOA growth. We applied GAMMA (McNeill et al. Environ. Sci. Technol. 2012, 46, 8075-8081), a photochemical box model with coupled gas-phase and detailed aqueous aerosol-phase chemistry, to simulate aerosol chamber studies of SOA formation by the uptake of glyoxal by wet aerosol under dark and irradiated conditions (Kroll et al. J. Geophys. Res. 2005, 110 (D23), 1-10; Volkamer et al. Atmos. Chem. Phys. 2009, 9, 1907-1928; Galloway et al. Atmos. Chem. Phys. 2009, 9, 3331- 306 3345 and Geophys. Res. Lett. 2011, 38, L17811). We find close agreement between simulated SOA growth and the results of experiments conducted under dark conditions using values of the effective Henry's Law constant of 1.3-5.5 × 10(7) M atm(-1). While irradiated conditions led to the production of some organic acids, organosulfates, and other oxidation products via well-established photochemical mechanisms, these additional product species contribute negligible aerosol mass compared to the dark uptake of glyoxal. Simulated results for irradiated experiments therefore fell short of the reported SOA mass yield by up to 92%. This suggests a significant light-dependent SOA formation mechanism that is not currently accounted for by known bulk photochemistry, consistent with recent laboratory observations of SOA production via photosensitizer chemistry.

Analytical Solution for Reactive Solute Transport Considering Incomplete Mixing

NASA Astrophysics Data System (ADS)

Bellin, A.; Chiogna, G.

2013-12-01

The laboratory experiments of Gramling et al. (2002) showed that incomplete mixing at the pore scale exerts a significant impact on transport of reactive solutes and that assuming complete mixing leads to overestimation of product concentration in bimolecular reactions. We consider here the family of equilibrium reactions for which the concentration of the reactants and the product can be expressed as a function of the mixing ratio, the concentration of a fictitious non reactive solute. For this type of reactions we propose, in agreement with previous studies, to model the effect of incomplete mixing at scales smaller than the Darcy scale assuming that the mixing ratio is distributed within an REV according to a Beta distribution. We compute the parameters of the Beta model by imposing that the mean concentration is equal to the value that the concentration assumes at the continuum Darcy scale, while the variance decays with time as a power law. We show that our model reproduces the concentration profiles of the reaction product measured in the Gramling et al. (2002) experiments using the transport parameters obtained from conservative experiments and an instantaneous reaction kinetic. The results are obtained applying analytical solutions both for conservative and for reactive solute transport, thereby providing a method to handle the effect of incomplete mixing on multispecies reactive solute transport, which is simpler than other previously developed methods. Gramling, C. M., C. F. Harvey, and L. C. Meigs (2002), Reactive transport in porous media: A comparison of model prediction with laboratory visualization, Environ. Sci. Technol., 36(11), 2508-2514.

Opportunities for research to improve employment for people with spinal cord injuries.

PubMed

Frieden, L; Winnegar, A J

2012-05-01

This paper reviews the literature pertaining to the employment of people who experience spinal cord injury (SCI) in the United States and recommending future research. The literature was reviewed with search terms such as SCI, employment, working from home and telework using databases in EBSCO, including Academic Search Complete and the American Psychological Association’s databases. Literature and findings on key factors related to employment illustrate the multiple dimensions of work environments, and health demands, that effect employment outcomes for people with SCI. Employment is important for people with SCI and valued in society. The literature reviewed indicates that researchers understand the work demands for people with SCI and may help to identify suitable supports, training and job opportunities. There remains a need for research focus on understanding future employment demands, necessary work skills, differing work environments and methods for increasing and preserving employment.

Current profile redistribution driven by neutral beam injection in a reversed-field pinch

DOE Office of Scientific and Technical Information (OSTI.GOV)

Parke, E.; Department of Physics, University of Wisconsin-Madison 1150 University Ave., Madison, Wisconsin 53706; Anderson, J. K.

2016-05-15

Neutral beam injection in reversed-field pinch (RFP) plasmas on the Madison Symmetric Torus [Dexter et al., Fusion Sci. Technol. 19, 131 (1991)] drives current redistribution with increased on-axis current density but negligible net current drive. Internal fluctuations correlated with tearing modes are observed on multiple diagnostics; the behavior of tearing mode correlated structures is consistent with flattening of the safety factor profile. The first application of a parametrized model for island flattening to temperature fluctuations in an RFP allows inferrence of rational surface locations for multiple tearing modes. The m = 1, n = 6 mode is observed to shift inward by 1.1 ± 0.6 cm withmore » neutral beam injection. Tearing mode rational surface measurements provide a strong constraint for equilibrium reconstruction, with an estimated reduction of q{sub 0} by 5% and an increase in on-axis current density of 8% ± 5%. The inferred on-axis current drive is consistent with estimates of fast ion density using TRANSP [Goldston et al., J. Comput. Phys. 43, 61 (1981)].« less

Detection of concealed explosives at stand-off distances using wide band swept millimetre waves

NASA Astrophysics Data System (ADS)

Andrews, David A.; Rezgui, Nacer D.; Smith, Sarah E.; Bowring, Nicholas; Southgate, Matthew; Baker, John G.

2008-10-01

Millimetre waves in the range 20 to 110 GHz have been used to detect the presence and thickness of dielectric materials, such as explosives, by measuring the frequency response of the return signal. Interference between the reflected signals from the front and back surfaces of the dielectric provides a characteristic frequency variation in the return signal, which may be processed to yield its optical depth [Bowring et al, Meas. Sci. Technol. 19, 024004 (2008)]. The depth resolution depends on the sweep bandwidth, which is typically 10 to 30 GHz. By using super-heterodyne detection the range of the object can also be determined, which enables a signal from a target, such as a suicide bomber to be extracted from background clutter. Using millimetre wave optics only a small area of the target is illuminated at a time, thus reducing interference from different parts of a human target. Results are presented for simulated explosive materials with water or human backing at stand-off distances. A method of data analysis that involves pattern recognition enables effective differentiation of target types.

PUBLISHER'S ANNOUNCEMENT: Important changes for 2008

NASA Astrophysics Data System (ADS)

Bedrock, Claire

2008-01-01

Having reviewed several aspects of IOP journal content, both in print and online, we have made some changes for 2008, some of which affect Semiconductor Science and Technology. Article numbering In common with many other IOP journals, Semiconductor Science and Technology has moved from sequential page numbering to an article numbering system. Articles will continue to be published on the web in advance of the print edition. The bibliographic citation will change slightly. Articles should be referenced using the six-digit article number in place of a page number, and this number must include any leading zeros. For instance: Surname X and Surname Y 2008 Semicond. Sci. Technol. 18 015003 A new look and feel Semiconductor Science and Technology has changed from European A4 format to a slightly smaller size, closer to US Letter format, and we have taken the opportunity to refresh the cover, in order to modernise the typography, and create a consistent look and feel across our range of publications. If you have any questions or comments about any of these changes, please contact us at sst@iop.org

Resistive sensitivity functions for van der Pauw astroid and rounded crosses and cloverleafs

NASA Astrophysics Data System (ADS)

Koon, Daniel; Hansen, Ole

2014-03-01

We have calculated the sensitivity of van der Pauw resistances to local resistive variations for circular, square and astroid discs of infinitesimal thickness, as well as for the families of rounded crosses and cloverleafs, as a function of specimen parameters, using the direct formulas of our recent paper (Koon et al. 2013 J. Appl. Phys.114 163710) applied to ``reciprocally dual geometries'' (swapped Dirichlet and Neumann boundary conditions) described by Mareš et al.(2012 Meas. Sci. Technol. 23 045004). These results show that (a) the product of any such sensitivity function times differential area, and thus (b) the ratio of any two sensitivities, is invariant under conformal mapping, allowing for the pointwise determination of the conformal mapping function. The family of rounded crosses, which is bounded in parameter space by the square, the astroid and an ``infinitesimally thin'' cross, seems to represent the best geometry for focusing transport measurements on the center of the specimen while minimizing errors due to edge- or contact-effects. Made possible by an SLU Faculty research grant.

Theory of electron g-tensor in bulk and quantum-well semiconductors

NASA Astrophysics Data System (ADS)

Lau, Wayne H.; Flatte', Michael E.

2004-03-01

We present quantitative calculations for the electron g-tensors in bulk and quantum-well semiconductors based on a generalized P.p envelope function theory solved in a fourteen-band restricted basis set. The dependences of g-tensor on structure, magnetic field, carrier density, temperature, and spin polarization have been explored and will be described. It is found that at temperatures of a few Kelvin and fields of a few Tesla, the g-tensors for bulk semiconductors develop quasi-steplike dependences on carrier density or magnetic field due to magnetic quantization, and this effect is even more pronounced in quantum-well semiconductors due to the additional electric quantization along the growth direction. The influence of quantum confinement on the electron g-tensors in QWs is studied by examining the dependence of electron g-tensors on well width. Excellent agreement between these calculated electron g-tensors and measurements [1-2] is found for GaAs/AlGaAs QWs. This work was supported by DARPA/ARO. [1] A. Malinowski and R. T. Harley, Phys. Rev. B 62, 2051 (2000);[2] Le Jeune et al., Semicond. Sci. Technol. 12, 380 (1997).

Lead isotopes and trace metal ratios of aerosols as tracers of Pb pollution sources in Kanpur, India

NASA Astrophysics Data System (ADS)

Sen, Indra; Bizimis, Michael; Tripathi, Sachchida; Paul, Debajyoti; Tyagi, Swati; Sengupta, Deep

2015-04-01

The anthropogenic flux of Pb in the Earth's surface is almost an order of magnitude higher than its corresponding natural flux [1]. Identifying the sources and pathways of anthropogenic Pb in environment is important because Pb toxicity is known to have adverse effects on human health. Pb pollution sources for America, Europe, and China are well documented. However, sources of atmospheric Pb are unknown in India, particularly after leaded gasoline was phased out in 2000. India has a developing economy with a rapidly emerging automobile and high temperature industry, and anthropogenic Pb emission is expected to rise in the next decade. In this study, we report on the Pb- isotope compositions and trace metal ratios of airborne particulates collected in Kanpur, an industrial city in northern India. The Pb concentration in the airborne particulate matter varies between 14-216 ng/m3, while the other heavy metals vary by factor of 10 or less, e.g. Cd=0.3-3 ng/m3, As=0.4-3.5 ng/m3, Zn=36-161 ng/m3, and Cu=3-22 ng/m3. The 206Pb/207Pb, 208Pb/206Pb, and 208Pb/207Pb vary between 1.112 - 1.129, 2.123-2.141, and 2.409-2.424 respectively, and are highly correlated with each other (R2>0.9). Pb isotopes and trace metal data reveals that coal combustion is the major source of anthropogenic Pb in the atmosphere, with limited contribution from mining and smelting processes. We further conclude that combination of Pb isotope ratios and V/Pb ratios are powerful tracers for Pb source apportionment studies, which is otherwise difficult to differentiate based only on Pb systematics [1] Sen and Peucker-Ehrenbrink (2012), Environ. Sci. Technol.(46), 8601-8609

Application of the integrating sphere method to separate the contributions of brown and black carbon in atmospheric aerosols.

PubMed

Wonaschütz, Anna; Hitzenberger, Regina; Bauer, Heidi; Pouresmaeil, Parissa; Klatzer, Barbara; Caseiro, Alexandre; Puxbaum, Hans

2009-02-15

Until about a decade ago, black carbon (BC) was thought to be the only light absorbing substance in the atmospheric aerosol except for soil or desert dust In more recent years, light absorbing polymeric carbonaceous material was found in atmospheric aerosols. Absorption increases appreciably toward short wavelengths, so this fraction was called brown carbon. Because brown carbon is thermally rather refractory, it influences the split between organic carbon (OC) and elemental carbon (EC) in thermal methods and, through its light absorption characteristics, leads to overestimations of BC concentrations. The goal of the present study was to extend the integrating sphere method to correct the BC signal for the contribution of brown carbon and to obtain an estimate of brown carbon concentrations. Humic acid sodium salt was used as proxy for brown carbon. The extended method is first tested on mixtures of test substances and then applied to atmospheric samples collected during biomass smoke episodes (Easter bonfires) in Austria. The resulting concentrations of black and brown carbon are compared to EC obtained with a widely used thermal method, the Cachier method (Cachier et al. Tellus 1989, 41B, 379-390) and a thermal-optical method (Schmid et al. Atmos. Environ. 2001, 35, 2111-2121), as well as to concentrations of humic like substances (HULIS) and to biomass smoke POM (particulate organic matter). Both the thermal methods were found to overestimate BC on days with large contributions of woodsmoke, which agrees with the findings of the method intercomparison study by Reisinger et at. (Environ. Sci. Technol. 2008, 42, 884-889). During the days of the bonfires, the Cachier method gave EC concentrations that were higher by a factor of 3.8 than the BC concentrations, while the concentrations obtained with the thermal-optical method were higher by a factor of 2.6.

SciEthics Interactive: Science and Ethics Learning in a Virtual Environment

ERIC Educational Resources Information Center

Nadolny, Larysa; Woolfrey, Joan; Pierlott, Matthew; Kahn, Seth

2013-01-01

Learning in immersive 3D environments allows students to collaborate, build, and interact with difficult course concepts. This case study examines the design and development of the TransGen Island within the SciEthics Interactive project, a National Science Foundation-funded, 3D virtual world emphasizing learning science content in the context of…

Characterizing Fluorocarbon Assisted Atomic Layer Etching of Si Using Cyclic Ar/C 4F 8 and Ar/CHF 3 Plasma

DOE PAGES

Metzler, Dominik; Li, Chen; Engelmann, Sebastian; ...

2016-09-08

With the increasing interest in establishing directional etching methods capable of atomic scale resolution for fabricating highly scaled electronic devices, the need for development and characterization of atomic layer etching (ALE) processes, or generally etch processes with atomic layer precision, is growing. In this work, a flux-controlled cyclic plasma process is used for etching of SiO 2 and Si at the Angstrom-level. This is based on steady-state Ar plasma, with periodic, precise injection of a fluorocarbon (FC) precursor (C 4F 8 and CHF 3), and synchronized, plasma-based Ar+ ion bombardment [D. Metzler et al., J Vac Sci Technol A 32,more » 020603 (2014), and D. Metzler et al., J Vac Sci Technol A 34, 01B101 (2016)]. For low energy Ar+ ion bombardment conditions, physical sputter rates are minimized, whereas material can be etched when FC reactants are present at the surface. This cyclic approach offers a large parameter space for process optimization. Etch depth per cycle, removal rates, and self-limitation of removal, along with material dependence of these aspects, were examined as a function of FC surface coverage, ion energy, and etch step length using in situ real time ellipsometry. The deposited FC thickness per cycle is found to have a strong impact on etch depth per cycle of SiO 2 and Si, but is limited with regard to control over material etching selectivity. Ion energy over the 20 to 30 eV range strongly impacts material selectivity. The choice of precursor can have a significant impact on the surface chemistry and chemically enhanced etching. CHF 3 has a lower FC deposition yield for both SiO 2 and Si, and also exhibits a strong substrate dependence of FC deposition yield, in contrast to C4F 8. The thickness of deposited FC layers using CHF 3 is found to be greater for Si than for SiO 2. X-ray photoelectron spectroscopy was used to study surface chemistry. When thicker FC films of 11 Å are employed, strong changes of FC film chemistry during a cycle are seen whereas the chemical state of the substrate varies much less. On the other hand, for FC film deposition of 5 Å for each cycle, strong substrate surface chemical changes are seen during an etching cycle. The nature of this cyclic etching with periodic deposition of thin FC films differs significantly from conventional etching with steady-state FC layers since surface conditions change strongly throughout each cycle.« less

Detection and kinetics of protein nitration in aerosols by NO2 and O3

NASA Astrophysics Data System (ADS)

Yang, H.; Zhang, Y.; Pöschl, U.

2009-04-01

The effects of air pollution on allergic diseases are not yet well-understood, but recent studies have shown that proteins are efficiently nitrated by polluted air (Franze et al., 2005) and that nitration enhances the allergenic potential of proteins such as the prominent birch pollen allergen Bet v 1 (Gruijthuijsen et al., 2006). Accordingly, the nitration of proteins in bioaerosol particles such as pollen and spores by NO2 and O3 might be a reason why allergies are on the increase in areas with traffic-related air pollution such as mega-cities and city clusters. In this study we have developed a method to determine the nitrotyrosine residue number per molecule in nitrated model proteins (bovine serum albumin, BSA; ovalbumin, OVA) by liquid chromatography coupled to UV-Vis photometry and mass spectrometry detectors (LC-DAD and LC-ESI-MS). Nitration experiments were carried out by exposing proteins to synthetic gas mixtures of nitrogen dioxide, ozone, nitrogen, synthetic air and water vapor. Reaction rates were measured at different concentration levels of NO2 and O3, and rate coefficients for the heterogeneous chemical reaction were determined. The implications for atmospheric aging and chemical transformation of bioaerosol particles and their potential effects on public health will be discussed. References: Franze, T., Weller, M.G., Niessner, R., Pöschl, U., Protein nitration by polluted air, Environ. Sci. Technol. 39, 1673-1678, 2005. Gruijthuijsen, Y.K., Grieshuber, I., Stöcklinger, A., Tischler, U., Fehrenbach, T., Weller, M.G., Vogel, L., Vieths, S., Pöschl, U., Duschl, A., Nitration enhances the allergenic potential of proteins, Int. Arch. Allergy Immunol. 141, 265-275, 2006.

Nanoscale topographic pattern formation on Kr{sup +}-bombarded germanium surfaces

DOE Office of Scientific and Technical Information (OSTI.GOV)

Perkinson, Joy C.; Madi, Charbel S.; Aziz, Michael J.

2013-03-15

The nanoscale pattern formation of Ge surfaces uniformly irradiated by Kr{sup +} ions was studied in a low-contamination environment at ion energies of 250 and 500 eV and at angles of 0 Degree-Sign through 80 Degree-Sign . The authors present a phase diagram of domains of pattern formation occurring as these two control parameters are varied. The results are insensitive to ion energy over the range covered by the experiments. Flat surfaces are stable from normal incidence up to an incidence angle of {theta} = 55 Degree-Sign from normal. At higher angles, the surface is linearly unstable to the formationmore » of parallel-mode ripples, in which the wave vector is parallel to the projection of the ion beam on the surface. For {theta} {>=} 75 Degree-Sign the authors observe perpendicular-mode ripples, in which the wave vector is perpendicular to the ion beam. This behavior is qualitatively similar to those of Madi et al. for Ar{sup +}-irradiated Si but is inconsistent with those of Ziberi et al. for Kr{sup +}-irradiated Ge. The existence of a window of stability is qualitatively inconsistent with a theory based on sputter erosion [R. M. Bradley and J. M. Harper, J. Vac. Sci. Technol. A 6, 2390 (1988)] and qualitatively consistent with a model of ion impact-induced mass redistribution [G. Carter and V. Vishnyakov, Phys. Rev. B 54, 17647 (1996)] as well as a crater function theory incorporating both effects [S. A. Norris et al., Nat. Commun. 2, 276 (2011)]. The critical transition angle between stable and rippled surfaces occurs 10 Degree-Sign -15 Degree-Sign above the value of 45 Degree-Sign predicted by the mass redistribution model.« less

Wave-induced mass transport affects daily Escherichia coli fluctuations in nearshore water.

PubMed

Ge, Zhongfu; Whitman, Richard L; Nevers, Meredith B; Phanikumar, Mantha S

2012-02-21

Characterization of diel variability of fecal indicator bacteria concentration in nearshore waters is of particular importance for development of water sampling standards and protection of public health. Significant nighttime increase in Escherichia coli (E. coli) concentration in beach water, previously observed at marine sites, has also been identified in summer 2000 from fixed locations in waist- and knee-deep waters at Chicago 63rd Street Beach, an embayed, tideless, freshwater beach with low currents at night (approximately 0.015 m s(-1)). A theoretical model using wave-induced mass transport velocity for advection was developed to assess the contribution of surface waves to the observed nighttime E. coli replenishment in the nearshore water. Using average wave conditions for the summer season of year 2000, the model predicted an amount of E. coli transported from water of intermediate depth, where sediment resuspension occurred intermittently, that would be sufficient to have elevated E. coli concentration in the surf and swash zones as observed. The nighttime replenishment of E. coli in the surf and swash zones revealed here is an important phase in the cycle of diel variations of E. coli concentration in nearshore water. According to previous findings in Ge et al. (Environ. Sci. Technol. 2010, 44, 6731-6737), enhanced current circulation in the embayment during the day tends to displace and deposit material offshore, which partially sets up the system by the early evening for a new period of nighttime onshore movement. This wave-induced mass transport effect, although facilitating a significant base supply of material shoreward, can be perturbed or significantly influenced by high currents (orders of magnitude larger than a typical wave-induced mass transport velocity), current-induced turbulence, and tidal forcing.

DiAs Web Monitoring: A Real-Time Remote Monitoring System Designed for Artificial Pancreas Outpatient Trials

PubMed Central

Place, Jérôme; Robert, Antoine; Brahim, Najib Ben; Patrick, Keith-Hynes; Farret, Anne; Marie-Josée, Pelletier; Buckingham, Bruce; Breton, Marc; Kovatchev, Boris; Renard, Eric

2013-01-01

Background Developments in an artificial pancreas (AP) for patients with type 1 diabetes have allowed a move toward performing outpatient clinical trials. “Home-like” environment implies specific protocol and system adaptations among which the introduction of remote monitoring is meaningful. We present a novel tool allowing multiple patients to monitor AP use in home-like settings. Methods We investigated existing systems, performed interviews of experienced clinical teams, listed required features, and drew several mockups of the user interface. The resulting application was tested on the bench before it was used in three outpatient studies representing 3480 h of remote monitoring. Results Our tool, called DiAs Web Monitoring (DWM), is a web-based application that ensures reception, storage, and display of data sent by AP systems. Continuous glucose monitoring (CGM) and insulin delivery data are presented in a colored chart to facilitate reading and interpretation. Several subjects can be monitored simultaneously on the same screen, and alerts are triggered to help detect events such as hypoglycemia or CGM failures. In the third trial, DWM received approximately 460 data per subject per hour: 77% for log messages, 5% for CGM data. More than 97% of transmissions were achieved in less than 5 min. Conclusions Transition from a hospital setting to home-like conditions requires specific AP supervision to which remote monitoring systems can contribute valuably. DiAs Web Monitoring worked properly when tested in our outpatient studies. It could facilitate subject monitoring and even accelerate medical and technical assessment of the AP. It should now be adapted for long-term studies with an enhanced notification feature. J Diabetes Sci Technol 2013;7(6):1427–1435 PMID:24351169

Wave-induced mass transport affects daily Escherichia coli fluctuations in nearshore water

USGS Publications Warehouse

Ge, Zhongfu; Whitman, Richard L.; Nevers, Meredith B.; Phanikumar, Mantha S.

2012-01-01

Characterization of diel variability of fecal indicator bacteria concentration in nearshore waters is of particular importance for development of water sampling standards and protection of public health. Significant nighttime increase in Escherichia coli (E. coli) concentration in beach water, previously observed at marine sites, has also been identified in summer 2000 from fixed locations in waist- and knee-deep waters at Chicago 63rd Street Beach, an embayed, tideless, freshwater beach with low currents at night (approximately 0.015 m s–1). A theoretical model using wave-induced mass transport velocity for advection was developed to assess the contribution of surface waves to the observed nighttime E. coli replenishment in the nearshore water. Using average wave conditions for the summer season of year 2000, the model predicted an amount of E. coli transported from water of intermediate depth, where sediment resuspension occurred intermittently, that would be sufficient to have elevated E. coli concentration in the surf and swash zones as observed. The nighttime replenishment of E. coli in the surf and swash zones revealed here is an important phase in the cycle of diel variations of E. coli concentration in nearshore water. According to previous findings in Ge et al. (Environ. Sci. Technol. 2010, 44, 6731–6737), enhanced current circulation in the embayment during the day tends to displace and deposit material offshore, which partially sets up the system by the early evening for a new period of nighttime onshore movement. This wave-induced mass transport effect, although facilitating a significant base supply of material shoreward, can be perturbed or significantly influenced by high currents (orders of magnitude larger than a typical wave-induced mass transport velocity), current-induced turbulence, and tidal forcing.

Nonlinear Polarization Conversion using Microring Resonators

DTIC Science & Technology

2007-06-08

Office MURI grant W911NF-04-01-0203. References 1. B. E. Little and S. T. Chu, Opt. Photon. News 11(11), 24 (2000). 2. G. Griffel , IEEE Photon. Technol...Thompson Learning, 1976). 15. S. J. Choi, K. Djordjev, S. J. Choi, P. D. Dapkus, W. Lin, G. Griffel , R. Menna, and J. Connoly, IEEE Photon. Technol. Lett

Determining Virtual Environment "Fit": The Relationship between Navigation Style in a Virtual Field Trip, Student Self-Reported Desire to Visit the Field Trip Site in the Real World, and the Purposes of Science Education

ERIC Educational Resources Information Center

Tutwiler, M. Shane; Lin, Ming-Chao; Chang, Chun-Yen

2013-01-01

In this study, a follow-up analysis of the data reported in Lin et al. ("Learn Media Technol." doi: 10.1080/17439884.2011.629660 , 2011), we investigated the relationship between student use of a virtual field trip (VFT) system and the probability of students reporting wanting to visit the national park site upon which the VFT was modeled,…

A high brightness source for nano-probe secondary ion mass spectrometry

NASA Astrophysics Data System (ADS)

Smith, N. S.; Tesch, P. P.; Martin, N. P.; Kinion, D. E.

2008-12-01

The two most prevalent ion source technologies in the field of surface analysis and surface machining are the Duoplasmatron and the liquid metal ion source (LMIS). There have been many efforts in this area of research to develop an alternative source [ S.K. Guharay, J. Orloff, M. Wada, IEEE Trans. Plasma Sci. 33 (6) (2005) 1911; N.S. Smith, W.P. Skoczylas, S.M. Kellogg, D.E. Kinion, P.P. Tesch, O. Sutherland, A. Aanesland, R.W. Boswell, J. Vac. Sci. Technol. B 24 (6) (2006) 2902-2906] with the brightness of a LMIS and yet the ability to produce secondary ion yield enhancing species such as oxygen. However, to date a viable alternative has not been realized. The high brightness and small virtual source size of the LMIS are advantageous for forming high resolution probes but a significant disadvantage when beam currents in excess of 100 nA are required, due to the effects of spherical aberration from the optical column. At these higher currents a source with a high angular intensity is optimal and in fact the relatively moderate brightness of today's plasma ion sources prevail in this operating regime. Both the LMIS and Duoplasmatron suffer from a large axial energy spread resulting in further limitations when forming focused beams at the chromatic limit where the figure-of-merit is inversely proportional to the square of the energy spread. Also, both of these ion sources operate with a very limited range of ion species. This article reviews some of the latest developments and some future potential in this area of instrument development. Here we present an approach to source development that could lead to oxygen ion beam SIMS imaging with 10 nm resolution, using a 'broad area' RF gas phase ion source.

Toward Understanding the Nature of a Partnership Between an Elementary Classroom Teacher and an Informal Science Educator

NASA Astrophysics Data System (ADS)

Weiland, Ingrid S.; Akerson, Valarie L.

2013-12-01

This study explored the nature of the relationship between a fifth-grade teacher and an informal science educator as they planned and implemented a life science unit in the classroom, and sought to define this relationship in order to gain insight into the roles of each educator. In addition, student learning as a result of instruction was assessed. Prior research has predominately examined relationships and roles of groups of teachers and informal educators in the museum setting (Tal et al. in Sci Educ 89:920-935, 2005; Tal and Steiner in Can J Sci Math Technol Educ 6:25-46, 2006; Tran 2007). The current study utilized case study methodology to examine one relationship (between two educators) in more depth and in a different setting—an elementary classroom. The relationship was defined through a framework of cooperation, coordination, and collaboration (Buck 1998; Intriligator 1986, 1992) containing eight dimensions. Findings suggest a relationship of coordination, which requires moderate commitment, risk, negotiation, and involvement, and examined the roles that each educator played and how they negotiated these roles. Consistent with previous examinations in science education of educator roles, the informal educator's role was to provide the students with expertise and resources not readily available to them. The roles played by the classroom teacher included classroom management, making connections to classroom activities and curricula, and clarifying concepts. Both educators' perceptions suggested they were at ease with their roles and that they felt these roles were critical to the optimization of the short time frames (1 h) the informal educator was in the classroom. Pre and posttest tests demonstrated students learned as a result of the programs.

SciServer: An Online Collaborative Environment for Big Data in Research and Education

NASA Astrophysics Data System (ADS)

Raddick, Jordan; Souter, Barbara; Lemson, Gerard; Taghizadeh-Popp, Manuchehr

2017-01-01

For the past year, SciServer Compute (http://compute.sciserver.org) has offered access to big data resources running within server-side Docker containers. Compute has allowed thousands of researchers to bring advanced analysis to big datasets like the Sloan Digital Sky Survey and others, while keeping the analysis close to the data for better performance and easier read/write access. SciServer Compute is just one part of the SciServer system being developed at Johns Hopkins University, which provides an easy-to-use collaborative research environment for astronomy and many other sciences.SciServer enables these collaborative research strategies using Jupyter notebooks, in which users can write their own Python and R scripts and execute them on the same server as the data. We have written special-purpose libraries for querying, reading, and writing data. Intermediate results can be stored in large scratch space (hundreds of TBs) and analyzed directly from within Python or R with state-of-the-art visualization and machine learning libraries. Users can store science-ready results in their permanent allocation on SciDrive, a Dropbox-like system for sharing and publishing files.SciServer Compute’s virtual research environment has grown with the addition of task management and access control functions, allowing collaborators to share both data and analysis scripts securely across the world. These features also open up new possibilities for education, allowing instructors to share datasets with students and students to write analysis scripts to share with their instructors. We are leveraging these features into a new system called “SciServer Courseware,” which will allow instructors to share assignments with their students, allowing students to engage with big data in new ways.SciServer has also expanded to include more datasets beyond the Sloan Digital Sky Survey. A part of that growth has been the addition of the SkyQuery component, which allows for simple, fast cross-matching between very large astronomical datasets.Demos, documentation, and more information about all these resources can be found at www.sciserver.org.

The effects of a heat acclimation protocol in persons with spinal cord injury.

PubMed

Trbovich, Michelle B; Kiratli, Jenny B; Price, Mike J

2016-12-01

Persons without spinal cord injury (SCI) physiologically acclimate between seven to fourteen consecutive days of exercise in the heat. Decreased resting and exercise core temperature, decreased heart rate, increased plasma volume and increased thermal comfort during exercise are changes consistent with heat acclimation. Autonomic dysfunction after SCI impairs heat dissipation through sweating and vasodilation. The purpose of this study is to determine if seven consecutive days of exercise in the heat would result in physiologic changes consistent with heat acclimation in persons with SCI. Ten persons with SCI divided into two groups: tetraplegia (n=5) and paraplegia (n=5) exercised in 35°C using an arm ergometer at 50% W peak for 30min followed by 15min rest. This protocol was repeated over seven consecutive days. Heart rate (HR), skin temperature, aural temperature (T aur ), rate of perceived exertion (RPE), rate of perceived thermal strain (RPTS), and plasma volume (PV) were measured throughout the protocol. There were no significant differences in resting T aur exercise T aur , mean skin temperature, HR, PV, RPE or RPTS over the 7 days for either the tetraplegic or paraplegic group. Participants with SCI did not demonstrate the ability to dissipate heat more efficiently over 7 days of exercise at 35°C. The lack of heat acclimation seen in persons with SCI has implications for the athlete and non-athlete alike. For the SCI athlete, inability to acclimate will impair performance and endurance especially in warm environments, compared to the person without SCI. For the SCI non-athlete, there is a greater risk of heat-related illness in warm environments that can negatively affect participation in outdoor activities and thus quality of life. Published by Elsevier Ltd.

Narrative environments and the capacity of disability narratives to motivate leisure-time physical activity among individuals with spinal cord injury.

PubMed

Perrier, Marie-Josée; Smith, Brett M; Latimer-Cheung, Amy E

2013-01-01

Few individuals with spinal cord injury (SCI) engage in the recommended amount of leisure time physical activity (LTPA). Yet little is known about how, and why, active individuals engage in specific types of LTPA. This study explored how a unique narrative environment and disability narratives motivated individuals with SCI to engage in LTPA. Fourteen individuals with SCI from a physical activity program participated in approximately hour-long interviews. Interviews were then subjected to a narrative analysis. Individuals who used a restitution narrative (n = 6) were motivated to engage in functional LTPA because of the desire to maintain the body and restore the past self. The individual who used the chaos narrative (n = 1) preferred solitary LTPA as exposure to others with SCI was a constant reminder of the lost, pre-injury self. Individuals who used a quest narrative (n = 7) explored LTPA options that fit with their interests; these individuals were open to new types of LTPA, such as sport and outdoor recreation. The plot of three disability narratives can all motivate the pursuit of LTPA; however, not all types of LTPA are seen as equal. LTPA interventions can be enhanced through the lessons learned from this unique type of environment. Despite individuals' views about their disability, they can still be motivated to engage in routine LTPA. Different theoretical determinants, such as health or social benefits, hold different relevance for LTPA among individuals with differing disability narratives. The environment provided by practitioners can therefore elicit some stories of SCI while stifling others. Open narrative environment will attract individuals to listen and maintain involvement in LTPA.

SciServer Compute brings Analysis to Big Data in the Cloud

NASA Astrophysics Data System (ADS)

Raddick, Jordan; Medvedev, Dmitry; Lemson, Gerard; Souter, Barbara

2016-06-01

SciServer Compute uses Jupyter Notebooks running within server-side Docker containers attached to big data collections to bring advanced analysis to big data "in the cloud." SciServer Compute is a component in the SciServer Big-Data ecosystem under development at JHU, which will provide a stable, reproducible, sharable virtual research environment.SciServer builds on the popular CasJobs and SkyServer systems that made the Sloan Digital Sky Survey (SDSS) archive one of the most-used astronomical instruments. SciServer extends those systems with server-side computational capabilities and very large scratch storage space, and further extends their functions to a range of other scientific disciplines.Although big datasets like SDSS have revolutionized astronomy research, for further analysis, users are still restricted to downloading the selected data sets locally - but increasing data sizes make this local approach impractical. Instead, researchers need online tools that are co-located with data in a virtual research environment, enabling them to bring their analysis to the data.SciServer supports this using the popular Jupyter notebooks, which allow users to write their own Python and R scripts and execute them on the server with the data (extensions to Matlab and other languages are planned). We have written special-purpose libraries that enable querying the databases and other persistent datasets. Intermediate results can be stored in large scratch space (hundreds of TBs) and analyzed directly from within Python or R with state-of-the-art visualization and machine learning libraries. Users can store science-ready results in their permanent allocation on SciDrive, a Dropbox-like system for sharing and publishing files. Communication between the various components of the SciServer system is managed through SciServer‘s new Single Sign-on Portal.We have created a number of demos to illustrate the capabilities of SciServer Compute, including Python and R scripts accessing a range of datasets and showing the data flow between storage and compute components.Demos, documentation, and more information can be found at www.sciserver.org.SciServer is funded by the National Science Foundation Award ACI-1261715.

Electrostatic turbulence intermittence driven by biasing in Texas Helimak

DOE Office of Scientific and Technical Information (OSTI.GOV)

Toufen, D. L.; Institute of Physics, University of São Paulo, 05315-970 São Paulo, São Paulo; Pereira, F. A. C.

We investigate changes in the intermittent sequence of bursts in the electrostatic turbulence due to imposed positive bias voltage applied to control the plasma radial electric field in Texas Helimak [K. W. Gentle and H. He, Plasma Sci. Technol. 10, 284 (2008)]—a toroidal plasma device with a one-dimensional equilibrium, magnetic curvature, and shear. We identify the burst characteristics by analyzing ion saturation current fluctuations collected in a large set of Langmuir probes. The number of bursts increase with positive biasing, giving rise to a long tailed skewed turbulence probability distribution function. The burst shape does not change much with themore » applied bias voltage, while their vertical velocity increases monotonically. For high values of bias voltage, the bursts propagate mainly in the vertical direction which is perpendicular to the radial density gradient and the toroidal magnetic field. Moreover, in contrast with the bursts in tokamaks, the burst velocity agrees with the phase velocity of the overall turbulence in both vertical and radial directions. For a fixed bias voltage, the time interval between bursts and their amplitudes follows exponential distributions. Altogether, these burst characteristics indicate that their production can be modelled by a stochastic process.« less

Numerical study of multiscale compaction-initiated detonation

NASA Astrophysics Data System (ADS)

Gambino, J. R.; Schwendeman, D. W.; Kapila, A. K.

2018-02-01

A multiscale model of heterogeneous condensed-phase explosives is examined computationally to determine the course of transient events following the application of a piston-driven stimulus. The model is a modified version of that introduced by Gonthier (Combust Sci Technol 175(9):1679-1709, 2003. https://doi.org/10.1080/00102200302373) in which the explosive is treated as a porous, compacting medium at the macro-scale and a collection of closely packed spherical grains capable of undergoing reaction and diffusive heat transfer at the meso-scale. A separate continuum description is ascribed to each scale, and the two scales are coupled together in an energetically consistent manner. Following piston-induced compaction, localized energy deposition at the sites of intergranular contact creates hot spots where reaction begins preferentially. Reaction progress at the macro-scale is determined by the spatial average of that at the grain scale. A parametric study shows that combustion at the macro-scale produces an unsteady detonation with a cyclical character, in which the lead shock loses strength and is overtaken by a stronger secondary shock generated in the partially reacted material behind it. The secondary shock in turn becomes the new lead shock and the process repeats itself.

Instability analysis of charges trapped in the oxide of metal-ultra thin oxide-semiconductor structures

NASA Astrophysics Data System (ADS)

Aziz, A.; Kassmi, K.; Maimouni, R.; Olivié, F.; Sarrabayrouse, G.; Martinez, A.

2005-09-01

In this paper, we present the theoretical and experimental results of the influence of a charge trapped in ultra-thin oxide of metal/ultra-thin oxide/semiconductor structures (MOS) on the I(Vg) current-voltage characteristics when the conduction is of the Fowler-Nordheim (FN) tunneling type. The charge, which is negative, is trapped near the cathode (metal/oxide interface) after constant current injection by the metal (Vg<0). Of particular interest is the influence on the Δ Vg(Vg) shift over the whole I(Vg) characteristic at high field (greater than the injection field (>12.5 MV/cm)). It is shown that the charge centroid varies linearly with respect to the voltage Vg. The behavior at low field (<12.5 MV/cm) is analyzed in référence A. Aziz, K. Kassmi, Ka. Kassmi, F. Olivié, Semicond. Sci. Technol. 19, 877 (2004) and considers that the trapped charge centroid is fixed. The results obtained make it possible to analyze the influence of the injected charge and the applied field on the centroid position of the trapped charge, and to highlight the charge instability in the ultra-thin oxide of MOS structures.

Influence of kinetic effects on the resonance behavior of the Multipole Resonance Probe

NASA Astrophysics Data System (ADS)

Oberrath, Jens; Mussenbrock, Thomas; Brinkmann, Ralf Peter

2012-10-01

Active plasma resonance spectroscopy is a well known diagnostic method. Many concepts of this method are theoretically investigated and realized as a diagnostic tool. One of these tools is the multipole resonance probe (MRP) [1]. The application of such a probe in plasmas with pressures of only a few Pa raises the question whether kinetic effects have to be taken into account or not. To address this question a kinetic model is necessary. A general kinetic model for an electrostatic concept of active plasma resonance spectroscopy has already been presented by the authors [2]. This model can be used to describe the dynamical behavior of the MRP, which is interpretable as a special case of the general model. Neglecting electron-neutral collisions, this model can be solved analytically. Based on this solution we derive an approximated expression for the admittance of the system to investigate the influence of kinetic effects on the resonance behavior of the MRP. [4pt] [1] M. Lapke et al., Plasma Sources Sci. Technol. 20, 2011, 042001[0pt] [2] J. Oberrath et al., Proceedings of the 30th International Conference on Phenomena in Ionized Gases, 28th August - 2nd September, 2011

Improved Kolsky tension bar for high-rate tensile characterization of materials

NASA Astrophysics Data System (ADS)

Song, Bo; Antoun, Bonnie R.; Connelly, Kevin; Korellis, John; Lu, Wei-Yang

2011-04-01

A new Kolsky tension bar has been re-designed and developed at Sandia National Laboratories, CA. The new design uses the concept that a solid striker is fired to impact an end cap attached to the open end of the gun barrel to generate dynamic tensile loading. The gun barrel here serves as part of the loading device. The incident bar that is connected to the gun barrel and the transmission bar follow the design similar to the Kolsky compression bar. The bar supporting and aligning systems are the same as those in the Kolsky compression bar design described by Song et al (2009 Meas. Sci. Technol. 20 115701). Due to the connection complication among the gun barrel, bars and specimen, stress-wave propagation in the new Kolsky tension bar system is comprehensively analyzed. Based on the stress-wave analysis, the strain gage location on the incident bar needs to be carefully determined. A highly precise laser-beam measurement system is recommended to directly measure the displacement of the incident bar end. Dynamic tensile characterization of a 4330-V steel using this new Kolsky tension bar is presented as an example.

A new approach to the inverse problem for current mapping in thin-film superconductors

NASA Astrophysics Data System (ADS)

Zuber, J. W.; Wells, F. S.; Fedoseev, S. A.; Johansen, T. H.; Rosenfeld, A. B.; Pan, A. V.

2018-03-01

A novel mathematical approach has been developed to complete the inversion of the Biot-Savart law in one- and two-dimensional cases from measurements of the perpendicular component of the magnetic field using the well-developed Magneto-Optical Imaging technique. Our approach, especially in the 2D case, is provided in great detail to allow a straightforward implementation as opposed to those found in the literature. Our new approach also refines our previous results for the 1D case [Johansen et al., Phys. Rev. B 54, 16264 (1996)], and streamlines the method developed by Jooss et al. [Physica C 299, 215 (1998)] deemed as the most accurate if compared to that of Roth et al. [J. Appl. Phys. 65, 361 (1989)]. We also verify and streamline the iterative technique, which was developed following Laviano et al. [Supercond. Sci. Technol. 16, 71 (2002)] to account for in-plane magnetic fields caused by the bending of the applied magnetic field due to the demagnetising effect. After testing on magneto-optical images of a high quality YBa2Cu3O7 superconducting thin film, we show that the procedure employed is effective.

Comprehensive evaluation of the linear stability of Alfvén eigenmodes driven by alpha particles in an ITER baseline scenario

NASA Astrophysics Data System (ADS)

Figueiredo, A. C. A.; Rodrigues, P.; Borba, D.; Coelho, R.; Fazendeiro, L.; Ferreira, J.; Loureiro, N. F.; Nabais, F.; Pinches, S. D.; Polevoi, A. R.; Sharapov, S. E.

2016-07-01

The linear stability of Alfvén eigenmodes in the presence of fusion-born alpha particles is thoroughly assessed for two variants of an ITER baseline scenario, which differ significantly in their core and pedestal temperatures. A systematic approach based on CASTOR-K (Borba and Kerner 1999 J. Comput. Phys. 153 101; Nabais et al 2015 Plasma Sci. Technol. 17 89) is used that considers all possible eigenmodes for a given magnetic equilibrium and determines their growth rates due to alpha-particle drive and Landau damping on fuel ions, helium ashes and electrons. It is found that the fastest growing instabilities in the aforementioned ITER scenario are core-localized, low-shear toroidal Alfvén eigenmodes. The largest growth-rates occur in the scenario variant with higher core temperatures, which has the highest alpha-particle density and density gradient, for eigenmodes with toroidal mode numbers n≈ 30 . Although these eigenmodes suffer significant radiative damping, which is also evaluated, their growth rates remain larger than those of the most unstable eigenmodes found in the variant of the ITER baseline scenario with lower core temperatures, which have n≈ 15 and are not affected by radiative damping.

Transplantation of Mesenchymal Stem Cells Promotes an Alternative Pathway of Macrophage Activation and Functional Recovery after Spinal Cord Injury

PubMed Central

Uchida, Kenzo; Guerrero, Alexander Rodriguez; Watanabe, Shuji; Sugita, Daisuke; Takeura, Naoto; Yoshida, Ai; Long, Guang; Wright, Karina T.; Johnson, William E.B.; Baba, Hisatoshi

2012-01-01

Abstract Mesenchymal stem cells (MSC) derived from bone marrow can potentially reduce the acute inflammatory response in spinal cord injury (SCI) and thus promote functional recovery. However, the precise mechanisms through which transplanted MSC attenuate inflammation after SCI are still unclear. The present study was designed to investigate the effects of MSC transplantation with a special focus on their effect on macrophage activation after SCI. Rats were subjected to T9–T10 SCI by contusion, then treated 3 days later with transplantation of 1.0×106 PKH26-labeled MSC into the contusion epicenter. The transplanted MSC migrated within the injured spinal cord without differentiating into glial or neuronal elements. MSC transplantation was associated with marked changes in the SCI environment, with significant increases in IL-4 and IL-13 levels, and reductions in TNF-α and IL-6 levels. This was associated simultaneously with increased numbers of alternatively activated macrophages (M2 phenotype: arginase-1- or CD206-positive), and decreased numbers of classically activated macrophages (M1 phenotype: iNOS- or CD16/32-positive). These changes were associated with functional locomotion recovery in the MSC-transplanted group, which correlated with preserved axons, less scar tissue formation, and increased myelin sparing. Our results suggested that acute transplantation of MSC after SCI modified the inflammatory environment by shifting the macrophage phenotype from M1 to M2, and that this may reduce the effects of the inhibitory scar tissue in the subacute/chronic phase after injury to provide a permissive environment for axonal extension and functional recovery. PMID:22233298

Experience of sleep in individuals with spinal cord injury

PubMed Central

Fogelberg, Donald J.; Leland, Natalie E.; Blanchard, Jeanine; Rich, Timothy J.; Clark, Florence A.

2017-01-01

Background Poor sleep contributes to adverse health outcomes making it important to understand sleep in medically vulnerable populations, including those with spinal cord injury (SCI). However, little attention has been paid to circumstances specific to SCI that may negatively impact sleep, or to consequences of poor sleep in this population. Objectives To examine the experience of sleep among individuals with SCI. Methodology Secondary analysis using thematic coding of qualitative data from an ethnographic study of community-dwelling adults with SCI. Results Sleep-related data were found in transcripts for 90% of the sample. Participants described diminished sleep duration and irregular sleep patterns. Several factors contributing to poor sleep were identified, including SCI-related circumstances and sleep environment. Participants also discussed how poor sleep affected occupational engagement. Conclusion This study highlights the extent of sleep disturbance experienced after SCI, the subsequent impact on occupational performance, and provides direction for clinical practice. PMID:28196449

Linking carbon and iron cycles by investigating transport, fate and mineralogy of iron-bearing colloids from peat-draining rivers - Scotland as model for high-latitude rivers

NASA Astrophysics Data System (ADS)

Wood, Deborah; Crocket, Kirsty; Brand, Tim; Stutter, Marc; Wilson, Clare; Schröder, Christian

2016-04-01

Linking carbon and iron cycles by investigating transport, fate and mineralogy of iron-bearing colloids from peat-draining rivers - Scotland as model for high-latitude rivers Wood, D.A¹, Crocket, K², Brand, T², Stutter, M³, Wilson, C¹ & Schröder, C¹ ¹Biological and Environmental Sciences, University of Stirling, Stirling, FK9 4LA ²Scottish Association for Marine Science, University of the Highlands and Islands, Dunbeg, Oban, PA37 1QA ³James Hutton Institute, Craigiebuckler, Aberdeen, AB15 8QH The biogeochemical iron cycle exerts significant control on the carbon cycle¹. Iron is a limiting nutrient in large areas of the world's oceans and its bioavailability controls CO2 uptake by marine photosynthesizing microorganisms. While atmospheric iron inputs to the open ocean have been extensively measured, global river inputs have likely been underestimated because most major world rivers exhibit extensive iron removal by flocculation and sedimentation during seawater mixing. Iron minerals and organic matter mutually stabilise each other², which results in a 'rusty carbon sink' in sediments³ on the one hand but may also enhance transport beyond the salinity gradient on the other. Humic-rich, high latitude rivers have a higher iron-carrying capacity⁴-⁶ but are underrepresented in iron flux calculations. The West Coast sea lochs in Scotland are fed by predominantly peatland drainage catchments, and the rivers entering the sea lochs carry a high load of organic matter. The short distance between many of these catchments and the coastal ocean facilitates source-to-sea research investigating transport, fate and mineralogy of iron-bearing colloids providing a good analogue for similar high latitude fjordic systems. We use SeaFAST+ICP-MS and Mössbauer spectroscopy to survey trace metal concentrations, with emphasis on iron concentrations, speciation and mineralogy, across salinity gradients. In combination with ultra-filtration techniques, this allows determination of the concentrations and chemical composition of different size fractions of iron-organic matter particles and colloids. We are developing new filtering and enrichment protocols to enable the use of Mössbauer spectroscopy in order to close a gap in the understanding of iron mineralogy in sub-micron particles. Here we will present results from a first sampling campaign in Loch Sunart and its tributaries. Acknowledgements: This is a MASTS-funded PhD project (GSS30). Preliminary work was supported by a SAGES PECRE grant to C.S., and a MASTS Visiting Fellowship award (VF41) to K.C. References: 1. Raiswell and Canfield (2012). The Iron Biogeochemical Cycle Past and Present. Geochemical Perspectives 1(1), 1-220. 2. Schröder et al. The biogeochemical iron cycle and astrobiology. Hyperfine Interactions in press. 3. Lalonde et al. (2012). Preservation of organic matter in sediments promoted by iron. Nature 483, 198-200. 4. Batchelli et al. (2010). Evidence for strong but dynamic iron-humic colloidal associations in humic-rich coastal waters. Environ. Sci. Technol., 44, 8485-8490. 5. Krachler et al. (2010). Relevance of peat-draining rivers for the riverine input of dissolved iron into the ocean. Sci. Total Environ., 408, 2402-2408. 6. Pokrovsky et al. (2014). Fate of colloids during estuarine mixing in the Arctic. Ocean Sci., 10, 107-125.

Sample-morphology effects on x-ray photoelectron peak intensities. III. Simulated spectra of model core–shell nanoparticles

DOE Office of Scientific and Technical Information (OSTI.GOV)

Powell, Cedric J., E-mail: cedric.powell@nist.gov; Chudzicki, Maksymilian; Werner, Wolfgang S. M.

2015-09-15

The National Institute of Standards and Technology database for the simulation of electron spectra for surface analysis has been used to simulate Cu 2p photoelectron spectra for four types of spherical copper–gold nanoparticles (NPs). These simulations were made to extend the work of Tougaard [J. Vac. Sci. Technol. A 14, 1415 (1996)] and of Powell et al. [J. Vac. Sci. Technol. A 31, 021402 (2013)] who performed similar simulations for four types of planar copper–gold films. The Cu 2p spectra for the NPs were compared and contrasted with analogous results for the planar films and the effects of elastic scatteringmore » were investigated. The new simulations were made for a monolayer of three types of Cu/Au core–shell NPs on a Si substrate: (1) an Au shell of variable thickness on a Cu core with diameters of 0.5, 1.0, 2.0, 5.0, and 10.0 nm; (2) a Cu shell of variable thickness on an Au core with diameters of 0.5, 1.0, 2.0, 5.0, and 10.0 nm; and (3) an Au shell of variable thickness on a 1 nm Cu shell on an Au core with diameters of 0.5, 1.0, 2.0, 5.0, and 10.0 nm. For these three morphologies, the outer-shell thickness was varied until the Cu 2p{sub 3/2} peak intensity was the same (within 2%) as that found in our previous work with planar Cu/Au morphologies. The authors also performed similar simulations for a monolayer of spherical NPs consisting of a CuAu{sub x} alloy (also on a Si substrate) with diameters of 0.5, 1.0, 2.0, 5.0, and 10.0 nm. In the latter simulations, the relative Au concentration (x) was varied to give the same Cu 2p{sub 3/2} peak intensity (within 2%) as that found previously. For each morphology, the authors performed simulations with elastic scattering switched on and off. The authors found that elastic-scattering effects were generally strong for the Cu-core/Au-shell and weak for the Au-core/Cu-shell NPs; intermediate elastic-scattering effects were found for the Au-core/Cu-shell/Au-shell NPs. The shell thicknesses required to give the selected Cu 2p{sub 3/2} peak intensity for the three types of core–shell NPs were less than the corresponding film thicknesses of planar samples since Cu 2p photoelectrons can be detected from the sides and, for the smaller NPs, bottoms of the NPs. Elastic-scattering effects were also observed on the Au atomic fractions found for the CuAu{sub x} NP alloys with different diameters.« less

Uncovering the Physical Basis Connecting Environment and Tribological Performance of Ultrananocrystalline Diamond

DTIC Science & Technology

2012-10-05

Anisotropic Nanotribological Properties,” Journal of the Mechanical Behavior of Biomedical Materials, Vol. 4, Issue 4, pp. 515-522 (SCI) Kuo -Cheng Chen...Nanodiamond With the Polymer Used as an Additive in Lubricant Oil,” Journal of Materials Chemistry, Vol. 21, pp. 13213-13222 (SCI) Chih- Jung Chen, Ray...Deep Submicron to Nano-Scale,” Journal of Mechanics, Vol. 28, Issue 3, pp. 507-511 (SCI) Yeau-Ren Jeng, Yi-Min Wang, Hua-Chiang Wen, Shih -Ming Huang

Japan Report, Science and Technology.

DTIC Science & Technology

1986-12-15

Sakamoto, "Glutathione," KODANSHA SCIENTIFIC (1985). 2. T. Tochikura, et al., J. FERMENT . TECHNOL., 45, 511 (1967). 3. Ibid., 46, 957 (1968). 4. S...Watanabe, et al., AGRIC. BIOL. CHEM., 36, 2265 (1972). 5. T. Tochikura, et al., J. FERMENT . TECHNOL., 48, 763 (1970). 6. T. Tachiki, et al., J. GEN. APPL...Tachiki and T. Tochikura, Fermentation and Industry, 41, 736, 1983). 13. K. Murata, J. Kato, and I. Senhata, Ibid., 39, 900 (1981). 14. Y. Isokazu

Residual Efficacy of Field-Applied Permethrin, d-Phenothrin, and Resmethrin on Plant Foliage Against Adult Mosquitoes

DTIC Science & Technology

2008-01-01

Kerst WC. 1997. Residue levels of pyrethrins and piperonyl butoxide in soil and runoff water. J Environ Sci Health B 32:621–644. Antonious GF, Snyder JC...Patel GA. 2001. Pyrethrins and piperonyl butoxide residues on potato leaves and in soil under field conditions. J Environ Sci Health B 36:261–271... metabolism of the pyrethroids cis- and trans- cypermethrin in rainbow trout, Salmo gairdneri. Xenobiotica 17:1175–1193. Foster WA. 1995. Mosquito sugar feeding

The association between health-related quality of life/dietary satisfaction and perceived food environment among Japanese individuals with spinal cord injury.

PubMed

Hata, K; Inayama, T; Yoshiike, N

2017-08-01

Cross-sectional. To examine the association between health-related quality of life (HRQOL)/dietary satisfaction and perceived food environment in community-dwelling individuals with spinal cord injury (SCI). Members of the Spinal Injuries Japan organization. Subjects were 2007 Japanese individuals with SCI. A questionnaire conducted in 2015 included items addressing sociodemographic characteristics, HRQOL, dietary satisfaction and eight perceived food environment items. Responses from 506 individuals were analyzed (valid response rate=25%). Dependent variables were the physical and mental summary scores of the HRQOL and dietary satisfaction. The independent variable was the perceived food environment. We used a univariate analysis (in Model 1) and a multivariate analysis (in Models 2 and 3) as part of a binominal logistic regression analysis. In Model 3, we divided and analyzed the perceived food environment variable into 'access to food' and 'access to information'. Both physical and mental summary scores were related to 'dietary information acquisition in the community'. Dietary satisfaction was related to 'balanced meals in the household', 'food and health information available from family' and 'right health and dietary information acquisition from the media'. HRQOL and dietary satisfaction were differentially associated with perceived food environment factors in community-dwelling individuals with SCI. HRQOL was positively related to dietary information of perceived food environment in the community. Dietary satisfaction was positively related to perceived food environment in the household.

Institutional profile: the national Swedish academic drug discovery & development platform at SciLifeLab

PubMed Central

Arvidsson, Per I; Sandberg, Kristian; Sakariassen, Kjell S

2017-01-01

The Science for Life Laboratory Drug Discovery and Development Platform (SciLifeLab DDD) was established in Stockholm and Uppsala, Sweden, in 2014. It is one of ten platforms of the Swedish national SciLifeLab which support projects run by Swedish academic researchers with large-scale technologies for molecular biosciences with a focus on health and environment. SciLifeLab was created by the coordinated effort of four universities in Stockholm and Uppsala: Stockholm University, Karolinska Institutet, KTH Royal Institute of Technology and Uppsala University, and has recently expanded to other Swedish university locations. The primary goal of the SciLifeLab DDD is to support selected academic discovery and development research projects with tools and resources to discover novel lead therapeutics, either molecules or human antibodies. Intellectual property developed with the help of SciLifeLab DDD is wholly owned by the academic research group. The bulk of SciLifeLab DDD's research and service activities are funded from the Swedish state, with only consumables paid by the academic research group through individual grants. PMID:28670468

Institutional profile: the national Swedish academic drug discovery & development platform at SciLifeLab.

PubMed

Arvidsson, Per I; Sandberg, Kristian; Sakariassen, Kjell S

2017-06-01

The Science for Life Laboratory Drug Discovery and Development Platform (SciLifeLab DDD) was established in Stockholm and Uppsala, Sweden, in 2014. It is one of ten platforms of the Swedish national SciLifeLab which support projects run by Swedish academic researchers with large-scale technologies for molecular biosciences with a focus on health and environment. SciLifeLab was created by the coordinated effort of four universities in Stockholm and Uppsala: Stockholm University, Karolinska Institutet, KTH Royal Institute of Technology and Uppsala University, and has recently expanded to other Swedish university locations. The primary goal of the SciLifeLab DDD is to support selected academic discovery and development research projects with tools and resources to discover novel lead therapeutics, either molecules or human antibodies. Intellectual property developed with the help of SciLifeLab DDD is wholly owned by the academic research group. The bulk of SciLifeLab DDD's research and service activities are funded from the Swedish state, with only consumables paid by the academic research group through individual grants.

Seasonal evolution of anionic, cationic and non-ionic surfactant concentrations in coastal aerosols from Askö, Sweden

NASA Astrophysics Data System (ADS)

Gérard, Violaine; Nozière, Barbara; Baduel, Christine

2015-04-01

Surfactants present in atmospheric aerosols are expected to enhance the activation into cloud droplets by acting on one of the two key parameters of the Köhler equation: the surface tension, σ. But because the magnitude of this effect and its regional and temporal variability are still highly uncertain [1,2], various approaches have been developed to evidence it directly in the atmosphere. This work presents the analysis of surfactants present in PM2.5 aerosol fractions collected at the coastal site of Askö, Sweden (58° 49.5' N, 17° 39' E) from July to October 2010. The total surfactant fraction was extracted from the samples using an improved double extraction technique. Surface tension measurements performed with the pendant drop technique [3] indicated the presence of very strong surfactants (σ ~ 30 - 35 mN/m) in these aerosols. In addition, these extractions were combined with colorimetric methods to determine the anionic, cationic and non-ionic surfactant concentrations [4,5], and provided for the first time interference-free surfactant concentrations in atmospheric aerosols. At this site, the total surfactant concentration in the PM2.5 samples varied between 7 to 150 mM and was dominated by anionic and non-ionic ones. The absolute surface tension curves obtained for total surfactant fraction displayed Critical Micelle Concentrations (CMC) in the range 50 - 400 uM, strongly suggesting a biological origin for the surfactants. The seasonal evolution of these concentrations and their relationships with environmental or meteorological parameters at the site will be discussed. [1] Ekström, S., Nozière, B. et al., Biogeosciences, 2010, 7, 387 [2] Baduel, C., Nozière, B., Jaffrezo, J.-L., Atmos. Environ., 2012, 47, 413 [3] Nozière, B., Baduel, C., Jaffrezo, J.-L., Nat. Commun., 2014, 5, 1 [4] Latif, M. T.; Brimblecombe, P. Environ. Sci. Technol., 2004, 38, 6501 [5] Pacheco e Silva et al., Method to measure surfactant in fluid, 2013, US 2013/0337568 A1

Heat Transfer by Thermo-capillary Convection -Sounding Rocket COMPERE Experiment SOURCE

NASA Astrophysics Data System (ADS)

Dreyer, Michael; Fuhrmann, Eckart

The sounding rocket COMPERE experiment SOURCE was successfully flown on MASER 11, launched in Kiruna (ESRANGE), May 15th, 2008. SOURCE has been intended to partly ful-fill the scientific objectives of the European Space Agency (ESA) Microgravity Applications Program (MAP) project AO-2004-111 (Convective boiling and condensation). Three parties of principle investigators have been involved to design the experiment set-up: ZARM for thermo-capillary flows, IMFT (Toulouse, France) for boiling studies, EADS Astrium (Bremen, Ger-many) for depressurization. The topic of this paper is to study the effect of wall heat flux on the contact line of the free liquid surface and to obtain a correlation for a convective heat trans-fer coefficient. The experiment has been conducted along a predefined time line. A preheating sequence at ground was the first operation to achieve a well defined temperature evolution within the test cell and its environment inside the rocket. Nearly one minute after launch, the pressurized test cell was filled with the test liquid HFE-7000 until a certain fill level was reached. Then the free surface could be observed for 120 s without distortion. Afterwards, the first depressurization was started to induce subcooled boiling, the second one to start saturated boiling. The data from the flight consists of video images and temperature measurements in the liquid, the solid, and the gaseous phase. Data analysis provides the surface shape versus time and the corresponding apparent contact angle. Computational analysis provides information for the determination of the heat transfer coefficient in a compensated gravity environment where a flow is caused by the temperature difference between the hot wall and the cold liquid. The paper will deliver correlations for the effective contact angle and the heat transfer coefficient as a function of the relevant dimensionsless parameters as well as physical explanations for the observed behavior. The data will be used for benchmarking of commercial CFD codes and the tank design (using these codes) of future cryogenic upper stages. References Eckart Fuhrmann, Michael E. Dreyer, Description of the Sounding Rocket Experiment SOURCE, Microgravity sci. technol., 20/3-4, 206 (2008)

Formation of nitro-PAHs from the heterogeneous reaction of ambient particle-bound PAHs with NO3/N2O5

NASA Astrophysics Data System (ADS)

Zimmermann, K.; Jariyasopit, N.; Simonich, S. L.; Atkinson, R.; Arey, J.

2012-12-01

Polycyclic aromatic hydrocarbons (PAHs) and their nitrated derivatives (nitro-PAHs) have been shown to be mutagenic in bacterial and mammalian assays and are classified as probable human carcinogens. Semi-volatile PAHs partition between the gas and particulate phases, depending on their liquid-phase vapor pressures and ambient temperatures. These PAHs have been extensively measured in ambient particulate matter and can ultimately undergo long-range transport from source regions (e.g., China to the western USA) (1). During transport these particle-bound PAHs may undergo reaction with NO3/N2O5 to form nitro-PAH derivatives. Previous studies of heterogeneous nitration of PAHs have used particles composed of graphite, diesel soot, and wood smoke (2-4). This study investigates the heterogeneous formation of nitro-PAHs from ambient particle-bound PAHs from Beijing, China and sites located within the Los Angeles air basin. These ambient particle samples, along with filters coated with isotopically labeled PAHs, were exposed to a mix of NO2/NO3/N2O5 in a 7000 L Teflon chamber, with analysis focused on the heterogeneous formation of molecular weight 247 and 273 nitro-PAHs. The heterogeneous formation of certain nitro-PAHs (including1-nitropyrene and 1- and 2-nitrotriphenylene) was observed for some, but not all, ambient samples. Formation of nitro-PAHs typically formed through gas-phase reactions (2-nitrofluoranthene and 2-nitropyrene) was not observed. The effect of particle age and local photochemical conditions during sampling on the degree of nitration in environmental chamber reactions, as well as ambient implications, will be presented. 1. Primbs, T.; Simonich, S.; Schmedding, D.; Wilson, G.; Jaffe, D.; Takami, A.; Kato, S.; Hatakeyama, S.; Kajii, Y. Environ. Sci. Technol. 2007, 41, 3551-3558. 2. Esteve, W.; Budzinski, H.; Villenave, E. Atmospheric Environment 2004, 38, 6063-6072. 3. Nguyen, M.; Bedjanian, Y.; Guilloteau, A. Journal of Atmospheric Chemistry 2009, 62, 139-150. 4. Kamens, R. M.; Zhi-Hua, F.; Yao, Y.; Chen, D.; Chen, S.; Vartiainen, M. Chemosphere 1994, 28, 1623-1632.

Ship-borne measurements of microbial enzymatic activity: A rapid biochemical indicator for microbial water quality monitoring

NASA Astrophysics Data System (ADS)

Stadler, Philipp; Loken, Luke; Crawford, John; Schramm, Paul; Sorsa, Kirsti; Kuhn, Catherine; Savio, Domenico; Striegl, Rob; Butman, David; Stanley, Emily; Farnleitner, Andreas H.; Zessner, Matthias

2017-04-01

Contamination of aquatic ecosystems by human and animal wastes is a global concern for water quality. Disclosing fate and transport processes of fecal indicator organism (FIO) in large water bodies is a big challenge due to material intensive and time consuming methods used in microbiological water quality monitoring. In respect of utilization of large surface water resources there is a dearth of rapid microbiological methods that allow a near-real time health related water quality monitoring to be implemented into early warning systems. The detection of enzymatic activities has been proposed as a rapid surrogate for microbiological pollution monitoring of water and water resources (Cabral, 2010; Farnleitner et al., 2001, 2002). Methods such as the beta-D-Glucuronidase assay (GLUC), targeting FIO such as E. coli, were established. New automated enzymatic assays have been implemented during the last years into on-site monitoring stations, ranging from ground- to surface waters (Ryzinska-Paier et al., 2014; Stadler et al., 2017, 2016). While these automated enzymatic methods cannot completely replace assays for culture-based FIO enumeration, they yielded significant information on pollution events and temporal dynamics on a catchment specific basis, but were restricted to stationary measurements. For the first time we conducted ship-borne and automated measurements of enzymatic GLUC activity on large fresh water bodies, including the Columbia River, the Mississippi River and Lake Mendota. Not only are automated enzymatic assays technically feasible from a mobile vessel, but also can be used to localize point sources of potential microbial fecal contamination, such as tributaries or storm drainages. Spatial and temporal patterns of enzymatic activity were disclosed and the habitat specific correlation with microbiological standard assays for FIO determined due to reference samples. The integration of rapid and automated enzymatic assays into well-established systems for ship-borne measurements of physico-chemical parameters, such as the FLAMe (Crawford et al., 2015), paves new ground for data interpretation and process understanding. Cabral, J.P.S., 2010. Water Microbiology. Bacterial Pathogens and Water. Int. J. Environ. Res. Public. Health 7, 3657-3703. doi:10.3390/ijerph7103657 Crawford, J.T., Loken, L.C., Casson, N.J., Smith, C., Stone, A.G., Winslow, L.A., 2015. High-speed limnology: using advanced sensors to investigate spatial variability in biogeochemistry and hydrology. Environ. Sci. Technol. 49, 442-450. doi:10.1021/es504773x Farnleitner, A. h., Hocke, L., Beiwl, C., Kavka, G. c., Zechmeister, T., Kirschner, A. k. t., Mach, R. l., 2001. Rapid enzymatic detection of Escherichia coli contamination in polluted river water. Lett. Appl. Microbiol. 33, 246-250. doi:10.1046/j.1472-765x.2001.00990.x Farnleitner, A.H., Hocke, L., Beiwl, C., Kavka, G.G., Mach, R.L., 2002. Hydrolysis of 4-methylumbelliferyl-β-d-glucuronide in differing sample fractions of river waters and its implication for the detection of fecal pollution. Water Res. 36, 975-981. doi:10.1016/S0043-1354(01)00288-3 Ryzinska-Paier, G., Lendenfeld, T., Correa, K., Stadler, P., Blaschke, A.P., Mach, R.L., Stadler, H., Kirschner, A.K.T., Farnleitner, A.H., 2014. A sensitive and robust method for automated on-line monitoring of enzymatic activities in water and water resources. Water Sci. Technol. J. Int. Assoc. Water Pollut. Res. 69, 1349-1358. doi:10.2166/wst.2014.032 Stadler, P., Blöschl, G., Vogl, W., Koschelnik, J., Epp, M., Lackner, M., Oismüller, M., Kumpan, M., Nemeth, L., Strauss, P., Sommer, R., Ryzinska-Paier, G., Farnleitner, A.H., Zessner, M., 2016. Real-time monitoring of beta-d-glucuronidase activity in sediment laden streams: A comparison of prototypes. Water Res. 101, 252-261. doi:10.1016/j.watres.2016.05.072 Stadler, P., Farnleitner, A.H., Zessner, M., 2017. Development and evaluation of a self-cleaning custom-built auto sampler controlled by a low-cost RaspberryPi microcomputer for online enzymatic activity measurements. Talanta 162, 390-397. doi:10.1016/j.talanta.2016.10.031

EDITORIAL: Announcing the 2011 Measurement Science and Technology Outstanding Paper Awards Announcing the 2011 Measurement Science and Technology Outstanding Paper Awards

NASA Astrophysics Data System (ADS)

Foss, John; Dewhurst, Richard; Fujii, Kenichi; Regtien, Paul; Tatam, Ralph

2012-06-01

Since 1991, Measurement Science and Technology has awarded a Best Paper prize. The Editorial Board of this journal believe that such a prize is an opportunity to thank authors for submitting their work, and serves as an integral part of the on-going quality review of the journal. The current breadth of topical areas that are covered by MST has made it advisable to expand the recognition of excellent publications. Hence, since 2005 the Editorial Board have presented 'Outstanding Paper Awards'. This year awards were presented in the areas of 'Measurement Science', 'Fluid Mechanics' and 'Precision Measurement'. Although the categories mirror subject sections in the journal, the Editorial Board consider articles from all categories in the selection process. 2011 Award Winners—Measurement Science Simultaneous measurement of internal and surrounding flows of a moving droplet using multicolour confocal micro-particle image velocimetry (micro-PIV) M Oishi, H Kinoshita, T Fujii and M Oshima Institute of Industrial Science, The University of Tokyo, 4-6-1 Komaba, Meguro-Ku, Tokyo 153-8505, Japan Interfaculty Initiative in Information Studies, The University of Tokyo, 4-6-1 Komaba, Meguro-Ku, Tokyo 153-8505, Japan Whilst the award last year [1] was concerned with the application of microscopy to ultra-high vacuum dynamic force measurements, this year's award [2] goes to another micro-measurement technique, one concerned with measurements related to particle image velocimetry. The technique relates to multiphase flow in microfluidic devices, and offers a non-contact methodology for examining simultaneous dynamic interactions between flows having different phases. There are several features which make this an excellent paper. It introduces its subject with a clear and concise description of previous advances in related measurement methods, before introducing the additional feature of two-colour fluorescent monitoring of flow in two independent optical channels. By adapting a conventional confocal microscope for PIV measurements, the authors describe how to measure multiphase flow having separate phases in a simultaneous way, exploiting fluorescent markers with wavelength separation. The measurement technique required the integration of several optical systems, including two different laser excitation sources. The novelty of the paper resides with the multicolour separation unit and its optical design, with two synchronized camera systems. Alignment and setting of optical components are crucial for efficient monitoring of light from the conjugate focus. All these experimental features are described in detail and with clarity. The technique gives a measurement methodology for velocity measurements in the x-y plane, in a two-phase medium. Additionally, the out-of-plane, z, component of velocity has been estimated analytically using three-dimensional two-component measured velocity data and the continuity equation. This computational method was exploited with experimental data in a post-processing operation to derive full three-dimensional velocity distributions. Examples are then provided of the behaviour of droplets with surrounding flow. Image sizes are typically 800 × 600 pixels with resolution in the x-y plane of 0.284 µm/pixel. For examples discussed within the paper, the recording frame rate was 990 fps with an exposure time of about 1 ms for high quality PIV images. The results section is detailed and convincing, before the paper reaches a set of concise conclusions. There is also a useful list of 22 references at the end of the paper. The paper was rated as excellent by one of the referees in the initial refereeing process, and since publication it has attracted a high number of downloads. It is bound to make an impact within the PIV community. Readers may also like to know that the authors have since published a related paper [3] which uses this technique to measure the microscopic interaction between red blood cells (RBCs) and surrounding flow. 2011 Award Winners—Fluid Mechanics Acoustic tomographic imaging of temperature and flow fields in air Manuela Barth and Armin Raabe University of Leipzig, Institute for Meteorology, Stephanstraße 3, 04103 Leipzig, Germany This paper [4] provides a valuable measurement strategy for volumetric measurements of the velocity and temperature fields in an airflow over large fields. Given that the speed of sound in the medium is influenced by humidity, the recovered temperature is termed 'acoustic virtual temperature' (Tav). The method is demonstrated for a volume of order 1 m3. It can, in principle, be scaled to a much larger domain. The inferred quantities, T(x, y, z, t) and bar v(x, y, z, t), are not intended to replace discrete point measurements (which can be obtained with substantially greater accuracy albeit with intrusive probes or added scattering particles). Rather, the time-resolved measurements will likely be very valuable for HVAC or micro-meteorological, etc measurements. The supporting theory and the respective literature base are succinctly presented. The experimental strategy, in which pairs of counter-propagating acoustic emitters/receivers criss-cross the measurement domain, is supported by the authors' form of an algebraic tomographic reconstruction technique. The demonstration experiment and representative results are clearly presented. The selection committee anticipates a positive response by those investigators whose application problem is compatible with the capabilities offered by this paper. 2011 Award Winner—Precision Measurement Diameter measurements of polystyrene particles with atomic force microscopy J Garnaes Danish Fundamental Metrology, Matematiktorvet 307, DK-2800 Kgs. Lyngby, Denmark This paper [5] describes a geometric diameter measurement of polystyrene spheres with nominal diameters of about 100 nm using atomic force microscopy (AFM). Although electron microscopy has conventionally been used for small diameter measurements, the method can only be used in vacuum, leading to significant changes in deformation as no meniscus of water is formed on the surface of the spheres placed in a vacuum. In this work, AFM is used for the height and distance measurements of the spheres placed on a mica substrate, allowing the measurement in air. Uncertainties in the diameter measurements have been evaluated in detail by taking into account influences of the deformations due to the AFM tip, substrate, surface tension effect of a thin water layer, interaction between the two spheres, and so on. The influence of air gaps introduced by imperfect packing of the spheres has also been evaluated quantitatively from the distribution of the measured diameters. Finally the geometric diameter of the polystyrene spheres has been determined with an uncertainty of 3 nm from the height and packing distance measurements. This paper has been downloaded more than 300 times since its publication. The selection committee members on the Precision Measurement Award, Dr K Fujii, Dr A Yacoot, Dr P Williams, Dr H Bosse, Professor X Chen and Dr T Eom, selected this paper from a strongly competitive list of ten candidates for its sophisticated idea and detailed evaluation of uncertainty in measurement. Considering its impact on accurate evaluation of particles using AFM, the paper was selected as the winner of the MST Precision Measurement Award for 2011. The chairmen would like to thank the authors for choosing to publish their work in Measurement Science and Technology, and hope that other researchers enjoy reading these works and feel encouraged to submit their own best work to the journal. References [1] Lübbe J, Tröger L, Torbrügge S, Bechstein R, Richter C, Kühnle A and Reichling M 2010 Achieving high effective Q-factors in ultra-high vacuum dynamic force microscopy Meas. Sci. Technol. 21 125501 (9pp) [2] Oishi M, Kinoshita H, Fujii T and Oshima M 2011 Simultaneous measurement of internal and surrounding flows of a moving droplet using multicolour confocal micro-particle image velocimetry (micro-PIV) Meas. Sci. Technol. 22 105401 (13pp) [3] Oishi M, Utsubo K, Kinoshita H, Fujii T and Oshima M 2012 Continuous and simultaneous measurement of the tank-treading motion of red blood cells and the surrounding flow using translational confocal micro-particle image velocimetry (micro-PIV) with sub-micron resolution Meas. Sci. Technol. 23 035301 (18pp) [4] Barth M and Raabe A 2011 Acoustic tomographic imaging of temperature and flow fields in air Meas. Sci. Technol. 22 035102 (13pp) [5] Garnaes J 2011 Diameter measurements of polystyrene particles with atomic force microscopy Meas. Sci. Technol. 22 094001 (8pp)

Combustion Processes Indoors: a Source of High OH Radical Concentrations Through the Photolysis of Hono

NASA Astrophysics Data System (ADS)

Bartolomei, V.; Gomez Alvarez, E.; Glor, M.; Gligorovski, S.; Temime-Roussel, B.; Quivet, E.; Strekowski, R.; Zetzsch, C.; Held, A. B.; Wortham, H.

2013-12-01

Hydroxyl radical (OH) is one of the most important oxidant species in the atmosphere controlling its self-oxidizing capacity. The main sources of OH radicals are photolysis of ozone and photolysis of nitrous acid (HONO), among the others. In the indoor air, the ozonolysis of alkenes has been suggested as the main OH formation pathway. The possibility for OH formation through photolytic pathways in the indoor environment has been, up to now, ignored (Gómez Alvarez et al., 2012). Models and indirect measurements to the present time predicted concentrations of OH radicals in the order of 104 -105 cm-3. Recently, by direct measurements we have detected high OH radical concentrations of 1.8 106 cm-3 in a classroom in Marseille and we demonstrated that its main source is the photolysis of HONO (Gómez Alvarez et al., 2013). The concentrations of HONO are quite high indoors, reaching levels in the order of a few tens of ppbV (Gómez Alvarez et al., 2013). This is mainly due to 1) direct combustion sources and 2) heterogeneous reactions of NO2 on the numerous surfaces present in the indoor environment. HONO levels of 30 ppb were measured in a previous campaign carried out in Bayreuth in July 2012 as direct emissions from the combustion of a candle. The combination between so high concentrations of HONO and higher than expected light transmissions indoors (or indoor artificial lighting) could have a significant impact on the OH concentrations indoors which could feasibly become considerably higher than we measured in our school campaign (Gomez Alvarez et al., 2013). In order to evaluate these upper limits under combustion conditions in the indoor environment, we have carried out a campaign in the LOTASC chamber (Bayreuth, Germany). For this aim, the exhaust fumes from the burning of a commonly used domestic candle have been introduced in the chamber. The chamber was irradiated under well research indoor lighting conditions. A thorough characterization of light intensities and span (wavelength distribution) indoors have been performed, which had been identified as a clear flaw in our knowledge restricting the advancement of indoor air quality models. OH concentration levels have been determined using d9-butanol as tracer, using the OH clock determination procedure by PTR-MS-TOF. The OH radical concentration was investigated using different light intensities representative from indoor conditions, both natural and artificial and also different levels of RH. The PSS model has been performed in order to evaluate the contribution of different sources to the OH radical concentrations indoors under these conditions. The obtained results from the PSS model clearly indicate that the main source of OH radical indoors under combustion conditions is the photolysis of HONO under typical indoor irradiation conditions. REFERENCES Gómez Alvarez E, Wortham H, Strekowski R, Zetzsch C, Gligorovski S (2012) Atmospheric photo-sensitized heterogeneous and multiphase reactions: From outdoors to indoors, Environ. Sci. Technol. 46, 1955-1963. Gómez Alvarez, E.; Amedro, D.; Afif, C. ; Gligorovski, S.; Schoemacker , C.; Fittschen, C. ; Doussin, J. F.; Wortham, H. (2013) Unexpectedly high indoor hydroxyl radical concentrations associated with nitrous acid. Proc. Natl. Acad. Sci. USA Accepted.

Two types of nonlinear wave equations for diffractive beams in bubbly liquids with nonuniform bubble number density.

PubMed

Kanagawa, Tetsuya

2015-05-01

This paper theoretically treats the weakly nonlinear propagation of diffracted sound beams in nonuniform bubbly liquids. The spatial distribution of the number density of the bubbles, initially in a quiescent state, is assumed to be a slowly varying function of the spatial coordinates; the amplitude of variation is assumed to be small compared to the mean number density. A previous derivation method of nonlinear wave equations for plane progressive waves in uniform bubbly liquids [Kanagawa, Yano, Watanabe, and Fujikawa (2010). J. Fluid Sci. Technol. 5(3), 351-369] is extended to handle quasi-plane beams in weakly nonuniform bubbly liquids. The diffraction effect is incorporated by adding a relation that scales the circular sound source diameter to the wavelength into the original set of scaling relations composed of nondimensional physical parameters. A set of basic equations for bubbly flows is composed of the averaged equations of mass and momentum, the Keller equation for bubble wall, and supplementary equations. As a result, two types of evolution equations, a nonlinear Schrödinger equation including dissipation, diffraction, and nonuniform effects for high-frequency short-wavelength case, and a Khokhlov-Zabolotskaya-Kuznetsov equation including dispersion and nonuniform effects for low-frequency long-wavelength case, are derived from the basic set.

Sub-grid scale combustion models for large eddy simulation of unsteady premixed flame propagation around obstacles.

PubMed

Di Sarli, Valeria; Di Benedetto, Almerinda; Russo, Gennaro

2010-08-15

In this work, an assessment of different sub-grid scale (sgs) combustion models proposed for large eddy simulation (LES) of steady turbulent premixed combustion (Colin et al., Phys. Fluids 12 (2000) 1843-1863; Flohr and Pitsch, Proc. CTR Summer Program, 2000, pp. 61-82; Kim and Menon, Combust. Sci. Technol. 160 (2000) 119-150; Charlette et al., Combust. Flame 131 (2002) 159-180; Pitsch and Duchamp de Lageneste, Proc. Combust. Inst. 29 (2002) 2001-2008) was performed to identify the model that best predicts unsteady flame propagation in gas explosions. Numerical results were compared to the experimental data by Patel et al. (Proc. Combust. Inst. 29 (2002) 1849-1854) for premixed deflagrating flame in a vented chamber in the presence of three sequential obstacles. It is found that all sgs combustion models are able to reproduce qualitatively the experiment in terms of step of flame acceleration and deceleration around each obstacle, and shape of the propagating flame. Without adjusting any constants and parameters, the sgs model by Charlette et al. also provides satisfactory quantitative predictions for flame speed and pressure peak. Conversely, the sgs combustion models other than Charlette et al. give correct predictions only after an ad hoc tuning of constants and parameters. Copyright 2010 Elsevier B.V. All rights reserved.

Simultaneous electrical and optical study of spoke rotation, merging and splitting in HiPIMS plasma

NASA Astrophysics Data System (ADS)

Klein, P.; Lockwood Estrin, F.; Hnilica, J.; Vašina, P.; Bradley, J. W.

2017-01-01

To gain more information on the temporal and spatial behaviour of self-organized spoke structures in HiPIMS plasmas, a correlation between the broadband optical image of an individual spoke (taken over 200 ns) and the current it delivers to the target has been made for a range of magnetron operating conditions. As a spoke passes over a set of embedded probes in the niobium cathode target, a distinct modulation in the local current density is observed, (typically up to twice the average value), matching very well the radially integrated optical emission intensities (obtained remotely with an ICCD camera). The dual diagnostic system allows the merging and splitting of a set of spokes to be studied as they rotate. It is observed that in the merger of two spokes, the trailing spoke maintains its velocity while the leading spoke either decreases its velocity or increases its azimuthal length. In the spoke splitting process, the total charge collected by an embedded probe is conserved. A simple phenomenological model is developed that relates the spoke mode number m to the spoke dimensions, spoke velocity and gas atom velocity. The results are discussed in the context of the observations of spoke dynamics made by Hecimovic et al (2015 Plasma Sources Sci. Technol. 24 045005)

Mobility of long-chain DNA in two-dimensional artificial gels

NASA Astrophysics Data System (ADS)

Turner, Stephen W. P.; Han, Jongyoon; Craighead, Harold G.

2000-03-01

In this study, a two-dimensional array of nanofabricated obstacles is used as an artificial gel to study the electrophoretic mobility dependence of DNA as a function of pore size, molecule length and electric field. Limitations in feature size have prevented previous studies from testing the crossover from the separating to the non-separating regime predicted by the biased reptation model of Lumpkin, Dejardin and Zimm[1] and the modified model of Duke, Semenov and Viovy.[2] That limitation is overcome in this work with the use of electron beam lithography to define features as small as 30 nm. Attainment of these feature sizes was made possible by the use of a sacrificial-layer-based technique for fluidics fabrication.[3] A novel band-launching strategy is used to provide band separation data for the first time in this system. Molecule lengths between 5 and 150 kilobases are studied for electric field strengths from 0.1 to 20 Volts per meter. [1] O. Lumpkin, P. Dejardin and B. Zimm, Biopolymers, Vol. 24, 1573-1593 (1985) [2] T. Duke, A. Semenov and J. Viovy, Phys. Rev. Lett. Vol. 69, No. 22, 3260-3263 (1992) [3] S. Turner, A. Perez, A. Lopez, and H. Craighead, J. Vac. Sci. Technol. B 16(6) 3835-3840 (1998)

Characterization of homoionic Fe 2+-type montmorillonite: Potential chemical species of iron contaminant

NASA Astrophysics Data System (ADS)

Kozai, Naofumi; Inada, Koichi; Adachi, Yoshifusa; Kawamura, Sachi; Kashimoto, Yusuke; Kozaki, Tamotsu; Sato, Seichi; Ohnuki, Toshihiko; Sakai, Takuro; Sato, Takahiro; Oikawa, Masakazu; Esaka, Fumitaka; Mitamura, Hisayoshi

2007-08-01

Fe 2+-montmorillonite with Fe 2+ ions occupying cation exchange sites is an ideal transformation product in bentonite buffer material. In our previous study on preparation and characterization of Fe 2+-montmorillonite, the montmorillonite sample that adsorbed Fe 2+ ions on almost all of the cation exchange sites was prepared using a FeCl 2 solution under an inert gas condition [N. Kozai, Y. Adachi, S. Kawamura, K. Inada, T. Kozaki, S. Sato, H. Ohashi, T. Ohnuki, T. Banba, J. Nucl. Sci. Technol. 38 (2001) 1141]. In view of the unstable nature of iron(II) chemical species, this study attempted to determine the potential contaminant iron chemical species in the sample. Nondestructive elemental analysis revealed that a small amount of chloride ions remained dispersed throughout the clay particles. The chloride ion retention may be due to the adsorption of FeCl + ion pairs in the initial FeCl 2 solution and the subsequent containment of the Cl - ions that are dissociated from the FeCl + ion pairs during excess salt removal treatment. Two explanations are advanced for the second process: the slow release of the remaining Cl - ions from the collapsed interlayer of the montmorillonite, and the transformation of a minor fraction of the remaining FeCl + ion pairs to iron(III) hydroxide chloride complexes having low solubility.

Temperature measurements in small holes drilled in superconducting bulk during pulsed field magnetization

NASA Astrophysics Data System (ADS)

Fujishiro, H.; Naito, T.; Furuta, D.; Kakehata, K.

2010-11-01

The time dependence of the temperatures T(z, t) has been measured along the thickness direction z in several drilled holes in a superconducting bulk during pulsed field magnetization (PFM) and the heat generation and heat transfer in the bulk have been discussed. In the previous paper [H. Fujishiro, S. Kawaguchi, K. Kakehata, A. Fujiwara, T. Tateiwa, T. Oka, Supercond. Sci. Technol. 19 (2006) S540], we calculated the T(z, t) profiles in the bulk by solving a three-dimensional heat-diffusion equation to reproduce the measured T(t) on the bulk surface; the heat generation took place adiabatically and the calculated T(z, t) was isothermal along the z direction. In this study, the measured T(z, t) at the top surface was higher than that at the bottom surface just after the pulse field application at t < 0.5 s, and then became isothermal with increasing time. These results suggest that the magnetic flux intrudes inhomogeneously into the bulk from the edge of the top surface and the periphery at the early stage. The inhomogeneous magnetic flux intrusion and the flux trap during PFM change depending on the strength of the pulsed field and the pulse number in the successive pulse field application.

Evaluation of microbial transformations of dissolved organic matter - what information can be extracted from high-field FTICR-MS elemental formula data sets?

NASA Astrophysics Data System (ADS)

Herzsprung, Peter; von Tümpling, Wolf; Harir, Mourad; Hertkorn, Norbert; Schmitt-Kopplin, Philippe; Norf, Helge; Weitere, Markus; Kamjunke, Norbert

2017-04-01

Transformation of DOC and DOM was and is widespread investigated (1-3). Due to the complex composition of DOC increased attention was payed to DOM quality change during degradation processes. In order to get a better insight in DOM transformation processes both resolution as a function of time and on a molecular level are promising. The observation of DOM quality changes requires sophisticated evaluation techniques. A new evaluation strategy of FTICR-MS elemental formula data sets is introduced. An experiment with seven flumes and leaf leachate was performed. All flumes were sampled on five dates (within 7 days) and the SPEDOM was characterized using high-field FTICR-MS analysis, resulting in together 35 elemental formula data sets. The time dependent change of components abundance was fitted by a simple linear regression model after normalization of mass peak intensities. All components were categorized by calculation of the slope (change of percent intensity per day) in all seven flumes. A positive slope means product formation, a negative slope means degradation of components. Specific data filtration was developed to find out components with relevant change of relative intensity. About 7000 different components were present in at least one of the 35 samples. Of those about 1800 components were present in all of the 35 samples. About 300 components with significant increase of intensity were identified. They were mainly unsaturated and oxygen-rich components (lignin-like or tannin-like) and had molecular masses less than 450 Dalton. A group of about 70 components was partially degraded (significant negative slope, present in all samples). These components were more saturated and less oxygen-rich compared to the product group and had molecular masses > 450 Dalton. A third group of about 150 components was identified with a tendency to total degradation (significant negative slope, not present in all samples, reduced or no abundance at the end of the experiment). They were highly saturated and oxygen-poor (lipid-like). As a conclusion components of biogeochemical groups (specified by their H/C and O/C coordinates in Van Krevelen diagrams) can be allocated to DOM transformation processes by their tendency of intensity change. References 1) Lechtenfeld, O.J., Kattner, G., Flerus, R., McCallister, S.L., Schmitt-Kopplin, P., Koch, B.P., 2014. Molecular transformation and degradation of refractory dissolved organic matter in the Atlantic and Southern Ocean. Geochim. Cosmochim. Acta 126, 321-337. 2) Morling, K., Herzsprung, P., Kamjunke, N., 2017. Discharge determines production of, decomposition of and quality changes in dissolved organic carbon in pre-dams of drinking water reservoirs. Sci. Tot. Environ. 577, 329-339. 3) Ohno, T., Parr, T.B., Gruselle, M.C.I., Fernandez, I.J., Sleighter, R.L., Hatcher, P.G., 2014. Molecular Composition and Biodegradability of Soil Organic Matter: A Case Study Comparing Two New England Forest Types. Environ. Sci. Technol. 48, 7229 - 7236.

A review of the liquid metal diffusion data obtained from the space shuttle endeavour mission STS-47 and the space shuttle columbia mission STS-52

NASA Astrophysics Data System (ADS)

Shirkhanzadeh, Morteza

Accurate data of liquid-phase solute diffusion coefficients are required to validate the condensed -matter physics theories. However, the required data accuracy to discriminate between com-peting theoretical models is 1 to 2 percent(1). Smith and Scott (2) have recently used the measured values of diffusion coefficients for Pb-Au in microgravity to validate the theoretical values of the diffusion coefficients derived from molecular dynamics simulations and several Enskog hard sphere models. The microgravity data used was obtained from the liquid diffusion experiments conducted on board the Space Shuttle Endeavour (mission STS-47) and the Space Shuttle Columbia (mission STS-52). Based on the analysis of the results, it was claimed that the measured values of diffusion coefficients were consistent with the theoretical results and that the data fit a linear relationship with a slope slightly greater than predicted by the molecular dynamics simulations. These conclusions, however, contradict the claims made in previous publications (3-5) where it was reported that the microgravity data obtained from the shuttle experiments fit the fluctuation theory (D proportional to T2). A thorough analysis of data will be presented to demonstrate that the widely-reported micro-gravity results obtained from shuttle experiments are not reliable and sufficiantly accurate to discriminate between competing theoretical models. References: 1. J.P. Garandet, G. Mathiak, V. Botton, P. Lehmann and A. Griesche, Int. J. Thermophysics, 25, 249 (2004). 2.P.J. Scott and R.W. Smith, J. Appl. Physics 104, 043706 (2008). 3. R.W. Smith, Microgravity Sci. Technol. XI (2) 78-84 (1998). 4.Smith et al, Ann. N.Y. Acad. Sci. 974:56-67 (2002) (retracted). 5.R.A. Herring et al, J. Jpn. Soc. Microgravity Appl., Vol.16, 234-244 (1999).

An assessment of sources and pathways of human exposure to polybrominated diphenyl ethers in the United States.

PubMed

Johnson-Restrepo, Boris; Kannan, Kurunthachalam

2009-07-01

Polybrominated diphenyl ethers (PBDEs) are ubiquitous in the indoor environment, owing to their use in consumer products ranging from electronics to mattresses, furniture, and carpets. People are exposed to PBDEs through inhalation of indoor air and ingestion, and dermal absorption of dust particles present in the air. In this study, concentrations of PBDEs were determined in indoor air and house dust collected from homes in Albany, New York, USA. Based on the measured concentrations of PBDEs in indoor air and dust, we estimated daily exposure dose (DED) of PBDEs. In addition, we used previously published PBDE concentrations reported for breast milk from Massachusetts, USA [Johnson-Restrepo, B., Addink, R., Wong, C., Arcaro, K., Kannan, K., 2007. Polybrominated diphenyl ethers and organochlorine pesticides in human breast milk from Massachusetts. USA. J. Environ. Monitor. 9, 1205-1212] and foodstuffs collected from Texas and Florida, USA [Schecter, A., Päpke, O., Harris, T.R., Tung, K.C., Musumba, A., Olson, J., Birnbaum, L., 2006. Polybrominated diphenyl ether (PBDE) levels in an expanded market basket survey of U.S. food and estimated PBDE dietary intake by age and sex. Environ. Health Perspect. 114, 1515-1520, Johnson-Restrepo, B., Kannan, K., Addink, R., Adams, D.H., 2005b. Polybrominated diphenyl ethers and polychlorinated biphenyls in a marine foodweb of coastal Florida. Environ. Sci. Technol. 39, 8243-8250], in an estimation of dietary exposure to PBDEs. The exposure assessment was performed for five age groups: infants (<1yr), toddlers (1-5yr), children (6-11yr), teenagers (12-19yr), and adults (20yr). The dust ingestion and air inhalation factors that we used were the US Environmental Protection Agency's (EPA) exposure factors, while the daily food intake rates (g/day) were derived from the US Department of Agriculture's (USDA) food intake surveys. The total DED of PBDEs was calculated by summation of the exposures from diet, indoor air, and house dust. The average estimated DED of PBDEs was the highest for breastfed infants (86.4ng/kg-bw/day), contributed primarily (91%) from the consumption of breast milk. The average DED of PBDEs for toddlers, children, teenagers, and adults was respectively, 13.3, 5.3, 3.5, and 2.9ng/kg-bw/day. Ingestion and dermal absorption of house dust are the major pathways of PBDE exposure in toddlers, children, teenagers, and adults accounting for, on average, 56-77% of the total PBDE intake.

Particulate matter in new technology diesel exhaust (NTDE) is quantitatively and qualitatively very different from that found in traditional diesel exhaust (TDE).

PubMed

Hesterberg, Thomas W; Long, Christopher M; Sax, Sonja N; Lapin, Charles A; McClellan, Roger O; Bunn, William B; Valberg, Peter A

2011-09-01

Diesel exhaust (DE) characteristic of pre-1988 engines is classified as a "probable" human carcinogen (Group 2A) by the International Agency for Research on Cancer (IARC), and the U.S. Environmental Protection Agency has classified DE as "likely to be carcinogenic to humans." These classifications were based on the large body of health effect studies conducted on DE over the past 30 or so years. However, increasingly stringent U.S. emissions standards (1988-2010) for particulate matter (PM) and nitrogen oxides (NOx) in diesel exhaust have helped stimulate major technological advances in diesel engine technology and diesel fuel/lubricant composition, resulting in the emergence of what has been termed New Technology Diesel Exhaust, or NTDE. NTDE is defined as DE from post-2006 and older retrofit diesel engines that incorporate a variety of technological advancements, including electronic controls, ultra-low-sulfur diesel fuel, oxidation catalysts, and wall-flow diesel particulate filters (DPFs). As discussed in a prior review (T. W. Hesterberg et al.; Environ. Sci. Technol. 2008, 42, 6437-6445), numerous emissions characterization studies have demonstrated marked differences in regulated and unregulated emissions between NTDE and "traditional diesel exhaust" (TDE) from pre-1988 diesel engines. Now there exist even more data demonstrating significant chemical and physical distinctions between the diesel exhaust particulate (DEP) in NTDE versus DEP from pre-2007 diesel technology, and its greater resemblance to particulate emissions from compressed natural gas (CNG) or gasoline engines. Furthermore, preliminary toxicological data suggest that the changes to the physical and chemical composition of NTDE lead to differences in biological responses between NTDE versus TDE exposure. Ongoing studies are expected to address some of the remaining data gaps in the understanding of possible NTDE health effects, but there is now sufficient evidence to conclude that health effects studies of pre-2007 DE likely have little relevance in assessing the potential health risks of NTDE exposures.

Revisiting the cape cod bacteria injection experiment using a stochastic modeling approach

USGS Publications Warehouse

Maxwell, R.M.; Welty, C.; Harvey, R.W.

2007-01-01

Bromide and resting-cell bacteria tracer tests conducted in a sandy aquifer at the U.S. Geological Survey Cape Cod site in 1987 were reinterpreted using a three-dimensional stochastic approach. Bacteria transport was coupled to colloid filtration theory through functional dependence of local-scale colloid transport parameters upon hydraulic conductivity and seepage velocity in a stochastic advection - dispersion/attachment - detachment model. Geostatistical information on the hydraulic conductivity (K) field that was unavailable at the time of the original test was utilized as input. Using geostatistical parameters, a groundwater flow and particle-tracking model of conservative solute transport was calibrated to the bromide-tracer breakthrough data. An optimization routine was employed over 100 realizations to adjust the mean and variance ofthe natural-logarithm of hydraulic conductivity (InK) field to achieve best fit of a simulated, average bromide breakthrough curve. A stochastic particle-tracking model for the bacteria was run without adjustments to the local-scale colloid transport parameters. Good predictions of mean bacteria breakthrough were achieved using several approaches for modeling components of the system. Simulations incorporating the recent Tufenkji and Elimelech (Environ. Sci. Technol. 2004, 38, 529-536) correlation equation for estimating single collector efficiency were compared to those using the older Rajagopalan and Tien (AIChE J. 1976, 22, 523-533) model. Both appeared to work equally well at predicting mean bacteria breakthrough using a constant mean bacteria diameter for this set of field conditions. Simulations using a distribution of bacterial cell diameters available from original field notes yielded a slight improvement in the model and data agreement compared to simulations using an average bacterial diameter. The stochastic approach based on estimates of local-scale parameters for the bacteria-transport process reasonably captured the mean bacteria transport behavior and calculated an envelope of uncertainty that bracketed the observations in most simulation cases. ?? 2007 American Chemical Society.

Repeated helicopter-based surveys of fugitive hydrocarbon emissions from tight oil operations: Persistence and driving factors

NASA Astrophysics Data System (ADS)

Englander, J. G.; Brandt, A. R.; Jackson, R. B.; Alvarez, R.; Lyon, D. R.

2016-12-01

A recent study used helicopters and optical gas imaging (infrared-based) to study hydrocarbon leaks [1] across numerous oil and gas producing basins. The appearance of leaks appeared to have small statistical correlations with factors such as age of wells, production rate, or water production. However, there have not been few if any attempts to observe the presence of leaks over time. In this work, we used the same helicopter-based optical gas imaging techniques to revisit wells in the Bakken formation that had previously been measured in 2014 [1] In this study, we visited 353 of the total 683 well pads in Bakken from the original study, and we also visited 50 randomly selected well pads that were newly developed between studies. We first examine the presence of leaks as a function of different factors, including: operator, number of wells, tanks, and treaters on a well pad; and numerous other possible emissions drivers. In addition, using the previous years observations as our prior, we conducted a Bayesian analysis to determine the likelihood of finding a leaking or non-leaking well pad and compared the observations to a Monte Carlo simulation of randomly distributed leaks. We find that the overall prevalence of observed emissions was similar for each year (11% for 2014 observations and 10% for 2015 observations). We also find whether a pad was found to be leaking in the first observation year had a statistically significant influence (4.9σ) on the presence of a leak in the following observation year. Similar levels of persistence are also apparent for non-leaking well pads. [1] D. R. Lyon, R. A. Alvarez, D. Zavala-Araiza, A. R. Brandt, R. B. Jackson, and S. P. Hamburg, "Aerial surveys of elevated hydrocarbon emissions from oil and gas production sites," Environ. Sci. Technol., p. acs.est.6b00705, Apr. 2016.

Charging and performance of the CubeSTAR satellite studied by numerical simulations

NASA Astrophysics Data System (ADS)

Miloch, Wojciech; Bekkeng, Tore André; Lindem, Torfinn

2012-07-01

A good understanding of spacecraft-plasma interaction is important for all space missions and experiments. The spacecraft potential is determined by the plasma, photoemission and other currents [1]. A charged object can significantly disturb the surrounding plasma, and lead to wake formation. The wake features, such as ion focusing, can influence the measurements of the plasma by the instruments onboard. A study of this problem using analytical models is difficult and can not account for all phenomena. This has encouraged use of numerical models for self-consistent studies of the plasma-object interactions on a detailed kinetic level [2][3]. With three-dimensional particle-in-cell (PIC) simulations [3][4], we address the spacecraft-plasma interaction in various plasma environments, and account for the self-consistent charging of the spacecraft by plasma and photoemission currents. As a specific case, we consider the interactions between plasma and a CubeSTAR satellite. CubeSTAR is a nano-satellite for the space weather studies being constructed in Norway, with the launch scheduled for year 2013. With a novel Langmuir probe system [5], it will measure the absolute electron densities with a high spatial resolution, allowing for studies of small scale plasma irregularities. We perform a systematic study of the role of the wakefield on the measurements with the Langmuir probes onboard the CubeSTAR for the plasma conditions relevant for the planned polar orbit. The simulation results are of relevance also for other spacecraft missions. [1] Whipple E C, Rep. Prog. Phys. 44, 1197 (1981). [2] Roussel J F and Berthelier J J, J. Geophys. Res. 109, A01104 (2004). [3] Yaroshenko V V et al., J. Geophys. Res. 116, A12218 (2011). [4] Miloch W J Kroll M and Block D 2010 Phys. Plasmas 17, 103703 (2010). [5] Bekkeng T A et al. Meas. Sci. Technol. 21, 085903 (2010).

Reactive oxygen species from secondary organic aerosols decomposition in water and surrogate lung lining fluid

NASA Astrophysics Data System (ADS)

Tong, H.; Shen, F.; Lakey, P. S. J.; Arangio, A. M.; Socorro, J.; Brune, W. H.; Lucas, K.; Poeschl, U.; Shiraiwa, M.

2016-12-01

Reactive oxygen species (ROS) play a significant role in climate and adverse health effects of air pollutants (Anglada, J. M. et al., 2015; Pöschl and Shiraiwa, 2015). Secondary organic aerosols (SOA) account for a major fraction of fine particles (Jimenez et al., 2009; Huang et al., 2014). Thus, studies on ROS production ability of SOA are important for comprehensive evaluation of the impacts of air particulate matter on climate change and public health. In this study, we have investigated ROS formation by laboratory-generated SOA particles using a variety of different experimental techniques including electron paramagnetic resonance spectrometry, dithiothreitol and fluorometric hydrogen peroxide assays, and LC-MS/MS spectrometry, we found substantial amounts of ROS species such as •OH, O2•-, RO•, R• and H2O2 were generated by isoprene, β-pinene, and naphthalene SOA upon interaction with water and surrogate lung lining fluid. Antioxidants contained in surrogate lung lining fluid scavenge •OH and O2•-efficiently, but not organic radicals. LC-MS/MS analysis and kinetic modeling suggest that organic hydroperoxides, which account for a major fraction of SOA particles (Docherty et al., 2005; Ehn et al., 2014) play a critical role in ROS formation (Tong et al., 2016). We also found the cellular responses of human alveolar basal epithelial (A549) and macrophage cells (THP-1) to SOA could be explained by the ROS yields, indicating a key role of ROS on the cytotoxicity of SOA. Anglada, J. M. et al., Acc. Chem. Res. 48, 575-583, 2015. Docherty, K. S. eta al. Environ. Sci. Technol. 39, 4049-4059, 2005. Ehn, M. et al., Nature 506, 476-479, 2014. Huang, R.-J. et al., Nature 514, 218-222, 2014. Jimenez, J. L. et al., Science 326, 1525-1529, 2009. Pöschl, U., and Shiraiwa, M. Chem. Rev., 115, 4440-4475, 2015. Tong, H. et al., Atmos. Chem. Phys. 16, 1761-1771, 2016.

Upscaling mixing in porous media from an experimental quantification of pore scale Lagrangian deformation statistics

NASA Astrophysics Data System (ADS)

Turuban, R.; Jimenez-Martinez, J.; De Anna, P.; Tabuteau, H.; Meheust, Y.; Le Borgne, T.

2014-12-01

As dissolved chemical elements are transported in the subsurface, their mixing with other compounds and potential reactivity depends on the creation of local scale chemical gradients, which ultimately drive diffusive mass transfer and reaction. The distribution of concentration gradients is in turn shaped by the spatial gradients of flow velocity arising from the random distribution of solid grains. We present an experimental investigation of the relationship between the microscale flow stretching properties and the effective large scale mixing dynamics in porous media. We use a flow cell that models a horizontal quasi two-dimensional (2D) porous medium, the grains of which are cylinders randomly positioned between two glass plates [de Anna et al. 2013]. In this setup, we perform both non diffusive and diffusive transport tests, by injecting respectively microsphere solid tracers and a fluorescent dye. While the dye front propagates through the medium, it undergoes in time a kinematic stretching that is controlled by the flow heterogeneity, as it encounters stagnation zones and high velocity channels between the grains. The spatial distribution of the dye can then be described as a set of stretched lamellae whose rate of diffusive smoothing is locally enhanced by kinematic stretching [Le Borgne et al., 2013]. We show that this representation allows predicting the temporal evolution of the mixing rate and the probability distribution of concentration gradients for a range of Peclet numbers. This upscaling framework hence provides a quantification of the dynamics of effective mixing from the microscale Lagrangian velocity statistics. References:[1] P. de Anna, J. Jimenez-Martinez, H. Tabuteau, R. Turuban, T. Le Borgne, M. Derrien,and Yves Méheust, Mixing and reaction kinetics in porous media : an experimental pore scale quantification, Environ. Sci. Technol. 48, 508-516, 2014. [2] Le Borgne, T., M. Dentz, E. Villermaux, Stretching, coalescence and mixing in porous media, Phys. Rev. Lett., 110, 204501 (2013)

Chemical analysis of solid materials by a LIMS instrument designed for space research: 2D elemental imaging, sub-nm depth profiling and molecular surface analysis

NASA Astrophysics Data System (ADS)

Moreno-García, Pavel; Grimaudo, Valentine; Riedo, Andreas; Neuland, Maike B.; Tulej, Marek; Broekmann, Peter; Wurz, Peter

2016-04-01

Direct quantitative chemical analysis with high lateral and vertical resolution of solid materials is of prime importance for the development of a wide variety of research fields, including e.g., astrobiology, archeology, mineralogy, electronics, among many others. Nowadays, studies carried out by complementary state-of-the-art analytical techniques such as Auger Electron Spectroscopy (AES), X-ray Photoelectron Spectroscopy (XPS), Secondary Ion Mass Spectrometry (SIMS), Glow Discharge Time-of-Flight Mass Spectrometry (GD-TOF-MS) or Laser Ablation Inductively Coupled Plasma Mass Spectrometry (LA-ICP-MS) provide extensive insight into the chemical composition and allow for a deep understanding of processes that might have fashioned the outmost layers of an analyte due to its interaction with the surrounding environment. Nonetheless, these investigations typically employ equipment that is not suitable for implementation on spacecraft, where requirements concerning weight, size and power consumption are very strict. In recent years Laser Ablation/Ionization Mass Spectrometry (LIMS) has re-emerged as a powerful analytical technique suitable not only for laboratory but also for space applications.[1-3] Its improved performance and measurement capabilities result from the use of cutting edge ultra-short femtosecond laser sources, improved vacuum technology and fast electronics. Because of its ultimate compactness, simplicity and robustness it has already proven to be a very suitable analytical tool for elemental and isotope investigations in space research.[4] In this contribution we demonstrate extended capabilities of our LMS instrument by means of three case studies: i) 2D chemical imaging performed on an Allende meteorite sample,[5] ii) depth profiling with unprecedented sub-nm vertical resolution on Cu electrodeposited interconnects[6,7] and iii) preliminary molecular desorption of polymers without assistance of matrix or functionalized substrates.[8] On the whole, these results prove the adequacy of LMS as a powerful analytical tool able to address a great variety of topics in in situ space research. References: [1] U. Rohner, J. A. Whitby, P. Wurz, Meas. Sci. Technol. 2003, 14, 2159. [2] W. B. Brinckerhoff, G. G. Managadze, R. W. McEntire, A. F. Cheng, W. J. Green, Rev. Sci. Instrum. 2000, 71, 536. [3] G. G. Managadze, P. Wurz, R. Z. Sagdeev, A. E. Chumikov, M. Tuley, M. Yakovleva, N. G. Managadze, A. L. Bondarenko, Sol. Syst. Res. 2010, 44, 376. [4] A. Riedo, M. Neuland, S. Meyer, M. Tulej, P. Wurz, J. Anal. At. Spectrom. 2013, 28, 1256. [5] M.B. Neuland, S. Meyer, K. Mezger, A. Riedo, M. Tulej, P. Wurz, Planet. Space Sci. 2014, 101, 196. [6] V. Grimaudo, P. Moreno-García, A. Riedo, M. B. Neuland, M. Tulej, P. Broekmann, P. Wurz, Anal. Chem. 2015, 87, 2037. [7] A. Riedo, V. Grimaudo, P. Moreno-García, M. B. Neuland, M. Tulej, P. Wurz, P. Broekmann, J. Anal. At. Spectrom. 2015, 30, 2371. [8] P. Moreno-García, V. Grimaudo, A. Riedo, M. Tulej, P. Wurz, P. Broekmann, submitted to Rapid. Commun. Mass Spectrom., 2016.

Hydrogels and Cell Based Therapies in Spinal Cord Injury Regeneration

PubMed Central

Assunção-Silva, Rita C.; Gomes, Eduardo D.; Silva, Nuno A.; Salgado, António J.

2015-01-01

Spinal cord injury (SCI) is a central nervous system- (CNS-) related disorder for which there is yet no successful treatment. Within the past several years, cell-based therapies have been explored for SCI repair, including the use of pluripotent human stem cells, and a number of adult-derived stem and mature cells such as mesenchymal stem cells, olfactory ensheathing cells, and Schwann cells. Although promising, cell transplantation is often overturned by the poor cell survival in the treatment of spinal cord injuries. Alternatively, the therapeutic role of different cells has been used in tissue engineering approaches by engrafting cells with biomaterials. The latter have the advantages of physically mimicking the CNS tissue, while promoting a more permissive environment for cell survival, growth, and differentiation. The roles of both cell- and biomaterial-based therapies as single therapeutic approaches for SCI repair will be discussed in this review. Moreover, as the multifactorial inhibitory environment of a SCI suggests that combinatorial approaches would be more effective, the importance of using biomaterials as cell carriers will be herein highlighted, as well as the recent advances and achievements of these promising tools for neural tissue regeneration. PMID:26124844

Announcing the 2013 Measurement Science and Technology Outstanding Paper Awards

NASA Astrophysics Data System (ADS)

Foss, John; Dewhurst, Richard; Yacoot, Andrew; Tadigadapa, Srinivas; Peters, Kara

2014-07-01

Since 1991, Measurement Science and Technology has awarded a Best Paper prize. The Editorial Board of this journal believe that such a prize is an opportunity to thank authors for submitting their work, and serves as an integral part of the on-going quality review of the journal. The current breadth of topical areas that are covered by MST has made it advisable to expand the recognition of excellent publications. Hence, since 2005 the Editorial Board have presented 'Outstanding Paper Awards'. This year awards were presented in the areas of Fluid Mechanics, Measurement Science, Precision Measurement, Sensors and Sensing Systems, and Optical and Laser-based Techniques. Although the categories mirror subject sections in the journal, the Editorial Board consider articles from all categories in the selection process. 2013 Award Winner—Fluid Mechanics Extraction of skin-friction fields from surface flow visualizations Tianshu Liu Department of Mechanical and Aerospace Engineering, Western Michigan University, Kalamazoo, MI 49008, USA The skin friction or wall shear stress, τ w, for a wall bounded turbulent flow is a quantity of fundamental importance. It is the basis for the wall unit, ν/u τ (kinematic viscosity/friction velocity: [τ w/ρ ]1/2), which establishes the intrinsic length scale in the flow. The selected paper [1] provides a comprehensive review of—and builds upon—prior techniques to obtain τ w values over an area of interest for flow past complex geometries. The quantities that can be measured by optical imaging are shown to be related to the skin friction by the optical flow equation, which in turn is solved numerically as an inverse problem via the variational approach. The paper provides a well defined set of guidelines for other investigators. Detailed examples of skin-friction measurements using luminescent oil films as well as temperature- and pressure-sensitive paints are presented. Quantitative uncertainty estimates are included in the paper. Given the importance of the wall shear stress (skin friction) in fluid mechanics and the notorious difficulty of measuring this quantity directly, this paper is expected to be a seminal contribution. The paper was one of four in the special feature on Wall Shear Stress organized by Professor A Naguib in the December 2013 issue. 2013 Award Winner—Measurement Science Analysis of calibration-free wavelength-scanned wavelength modulation spectroscopy for practical gas sensing using tunable diode lasers K Sun, X Chao, R Sur, C S Goldenstein, J B Jeffries and R K Hanson High Temperature Gasdynamics Laboratory, Department of Mechanical Engineering, Stanford University, Stanford, CA 94305, USA In the previous two years, the Measurement Science Award has gone to important papers in diagnostic fields, namely particle image velocimetry (PIV [2]) and x-ray micro-computed tomographic systems [3]. This year's award [4] goes to another diagnostic field, infrared spectroscopy for practical gas sensing. Infrared spectroscopy is a very important topic for measurement science, concerned with the monitoring of gases in our environment. Over two decades, this form of spectroscopy has been enabled with the development of tunable diode lasers (TDLs). Hence, tunable diode laser absorption spectroscopy (TDLAS) is now an established method for in situ measurements of gas composition, temperature, pressure and velocity. Gases such as ammonia, methane, carbon dioxide and monoxide, hydrogen chloride, hydrogen fluoride and sulfur dioxide can all be monitored by commercially available systems. Some advances have been associated with improvements in infrared detectors or in the properties of some diode lasers. For homogeneous gases, the interpretation using the Beer-Lambert law and direct absorption (DA) is quite straightforward. DA is the preferred method when an absorption line can be found in the infrared region with an isolated transition of sufficient strength, and with a linewidth small enough to allow the laser to be wavelength-scanned on the absorption line, and just off it (as a reference baseline). Otherwise, wavelength modulation spectroscopy (WMS) is used for those cases where the gas offers small absorbance, or high pressure or for absorbers with closely spaced transitions, which are blended in the wings precluding measurement of a non-absorbing baseline. WMS is a powerful technique, but the interpretation is more complex, and the authors explain in their introduction the strategies that are normally adopted for data interpretation. In this new paper, the authors explain a new strategy for wavelength modulation spectroscopy. The strategy is different in two significant ways. Firstly, the measured laser intensity is used to simulate the transmitted laser intensity. Secondly, digital lock-in and low-pass filter software is used to expand both simulated and measured transmitted laser intensities into harmonics of the modulation frequency. In this way, the analysis scheme does not require an isolated transition; instead it recovers the lineshape for absorption from unresolved blended transitions. The paper goes on to describe an example using this novel method. It discusses the analysis of WMS absorption detection using water as an example. The advantages of the new method are explained, and a comparison is made with the more usual Fourier analysis approach. This paper is excellent in its clarity, presentation and scientific description. Issues have been clearly identified, and a new method of analysis has been presented with some evidence of validation. Its conclusions contain an in-depth summary, and the following 42 references are informative and representative of what is a very large field of study. It was voted as the best paper from a shortlist of 12 nominated papers. 2013 Award Winner—Precision Measurement Interferometric diameter determination of a silicon sphere using a traceable single laser frequency synthesizer Xuejian Wu, Yan Li, Haoyun Wei, Honglei Yang, Guoce Yang and Jitao Zhang State Key Lab of Precision Measurement Technology and Instruments, Department of Precision Instrument, Tsinghua University, Beijing 100084, People's Republic of China This paper [5] describes the determination of the absolute diameter of a silicon sphere for the Avogadro project using a phase shifting interferometer based on a flat etalon. The absolute diameter is attained by combining the fractional and integral measurement results, which are measured with phase shifting interferometry and frequency sweeping interferometry using laser frequency tuning, respectively. An optical frequency comb is used as the frequency ruler to measure and control the frequency of an external cavity diode laser in order to reduce the uncertainty contribution from the laser frequency on the phase steps to an insignificant level. The Carré algorithm with arbitrary but equal phase steps is used to calculate the fractional interference phases according to the characteristic of single laser frequency synthesiser. The paper provides a comprehensive description of the measurement techniques together with an uncertainty budget for the measurement of a silicon sphere. An overall measurement uncertainty of 5 nm is achieved. This paper has been downloaded more than 130 times since its publication. The selection committee members on the Precision Measurement Award, Dr A Yacoot, Dr P Williams, Dr H Bosse, Professor X Chen and Dr T Eom, selected this paper from a strongly competitive list of several candidates. Considering its impact on accurate evaluation of the measurement of silicon spheres, the paper was selected as the winner of the Precision Measurement Award for 2013. 2013 Award Winner—Sensors and Sensing Systems Enhancing the dynamic range of ultrasound imaging velocimetry using interleaved imaging C Poelma1 and K H Fraser 2 1Laboratory for Aero and Hydrodynamics (3ME-P&E), Delft University of Technology, Leeghwaterstraat 21, 2628 CA Delft, The Netherlands 2Department of Bioengineering, Imperial College London, South Kensington Campus, SW7 2AZ London, UK This paper [6] presents an innovative interleaved imaging technique to overcome the dynamic velocity range limitation of current ultrasound imaging velocimetry. Due to the nature of the recording of ultrasound images, the conversion from pixel displacement to velocities is less straightforward since the lines of an image are not recorded at the same time, so the inter-frame time needs to be corrected for any displacement. The upper limit of displacement velocities is widely reported in the literature as a major problem with the best measured in-vivo flow rates of ~ 70-80 cm s-1 or by restricting the field of view to as high as 140 cm s-1. In this study, the authors introduce a novel imaging method that enhances the dynamic range of ultrasound imaging velocimetry by an interleaved read-out approach. Using this technique, the inter-frame time is no longer fixed to the imaging rate and allows for the displacement of fast flows to be reduced by choosing an appropriate image offset parameter. The authors show that this technique allows for measurement of flows of up to 140 cm s-1 with the maximum lateral field of view and unrestricted depth. In their winning paper the authors have very clearly articulated the dynamic range limitations of the flow measurement using ultrasound imaging velocimetry and have very elegantly described the theory and experimental implementation of the interleaved imaging technique. The superior performance of the proposed method is clearly demonstrated through experimental results and images analyzed using the necessary mathematical transforms. The improved dynamic flow rate measurements using ultrasound imaging velocimetry made feasible using this technique are likely to have a significant impact on non-invasive blood flow monitoring for clinical screening and post-operative monitoring. 2013 Award Winner—Optical and Laser-based Techniques Detection of excited level population transfer in an MOT through the measurement of trapped atom number. L Moi1, G Batignani1, A Khanbekyan1, K Khanbekyan1, C Marinelli1, E Mariotti1, L Marmugi1, L Corradi2, A Dainelli2, R Calabrese3, G Mazzocca3, L Tomassetti3 and P Minguzzi4 1CNISM, Physics Department, University of Siena, via Roma 56, 53100 Siena, Italy 2INFN—Laboratori Nazionali di Legnaro, viale dell'Università 2, 35020 Legnaro (PD), Italy 3University of Ferrara and INFN, via Saragat 1, 44122 Ferrara, Italy 4CNISM, Physics Department, University of Pisa, largo Pontecorvo 3, 56127 Pisa, Italy The selected paper [7] applies a direct fluorescence detection scheme to monitor the very low number of trapped atoms, simulating the conditions in a francium magneto-optical trap (MOT). Precise atomic parity nonconservation measurements are inherently difficult due to the fact that extremely weak signals must be detected. By scanning a probe beam across a resonance condition and then detecting the MOT fluorescence, the authors were able to monitor the population transfer from the ground level and the first excited level in the MOT. The significance of this work is that it presents a rapid and flexible method to detect the number of trapped atoms in conditions where very low numbers of these atoms are present. Such high precision measurements are essential in nuclear physics and are fundamental to our understanding of nuclear decay processes. We have selected this article for the Best Paper Award because the measurement technique demonstrated is not only innovative, but also flexible to implement as it is wavelength independent and presents a high signal to noise ratio. The experimental configuration was also extremely well documented in the paper, including a detailed estimate of the detection limits. Data were presented for many different excitation mechanisms to show the wide applicability of the measurement technique. It is expected that this innovative measurement strategy will be seen in successful applications of the study of atomic parity nonconservation in different nuclear particles in the near future. The chairmen would like to thank the authors for choosing to publish their work in Measurement Science and Technology , and hope that other researchers enjoy reading these works and feel encouraged to submit their own best work to the journal. References [1] Liu T 2013 Extraction of skin-friction fields from surface flow visualizations as an inverse problem Meas. Sci. Technol 24 124004 [2] Oishi M, Kinoshita H, Fujii T and Oshima M 2011 Simultaneous measurement of internal and surrounding flows of a moving droplet using multicolour confocal micro-particle image velocimetry micro-PIV Meas. Sci. Technol. 22 105401 [3] Hiller J, Maisl M and Reindl L M 2012 Physical characterization and performance evaluation of an x-ray micro-computed tomography system for dimensional metrology applications Meas. Sci. Technol 23 085404 [4] Sun K, Chao X, Sur R, Goldenstein C S, Jeffries J B and Hanson R K 2013 Analysis of calibration-free wavelength-scanned wavelength modulation spectroscopy for practical gas sensing using tunable diode lasers Meas. Sci. Technol 24 125203 [5] Wu X et al 2013 Interferometric diameter determination of a silicon sphere using a traceable single laser frequency synthesizer Meas. Sci. Technol. 24 115202 [6] Poelma C and Fraser K H 2013 Enhancing the dynamic range of ultrasound imaging velocimetry using interleaved imaging Meas. Sci. Technol. 24 115701 [7] Moi L et al 2013 Detection of excited level population transfer in an MOT through the measurement of trapped atom number Meas. Sci. Technol. 24 015201

Data supporting Al-Abed et al., Environ. Sci.: Nano, 2016,

EPA Pesticide Factsheets

Data files representing each of the Figures and Tables published in Al-Abed et al., Environ. Sci.: Nano, 2016,3, 593. The data file names identify the Figure or Table and each file contains an internal set of data definitionsThis dataset is associated with the following publication:Al-Abed, S.R., J. Virkutyte, J. Ortenzio , R.M. McCarrick, L. Degn, R. Zucker , N. Coates , K. Cleveland, H. Ma, S. Diamond, K. Dreher , and W. Boyes. Environmental aging alters AI(OH)3 coating of TiO2 nanoparticles enhancing their photocatalytic and phototoxicity activities. Environmental Science: Nano. RSC Publishing, Cambridge, UK, N/A, (2016).

Reply to the EFSA (2016) on the relevance of recent publications (Hofmann et al. 2014, 2016) on environmental risk assessment and management of Bt-maize events (MON810, Bt11 and 1507).

PubMed

Kruse-Plass, Maren; Hofmann, Frieder; Kuhn, Ulrike; Otto, Mathias; Schlechtriemen, Ulrich; Schröder, Boris; Vögel, Rudolf; Wosniok, Werner

2017-01-01

In this commentary, we respond to a report of the EFSA GMO Panel (EFSA EFSA Supp Publ, 1) that criticises the outcomes of two studies published in this journal (Hofmann et al. Environ Sci Eur 26: 24, 2; Environ Sci Eur 28: 14, 3). Both publications relate to the environmental risk assessment and management of Bt-maize, including maize events MON810, Bt11 and maize 1507. The results of Hofmann et al. (Environ Sci Eur 26: 24, 2), using standardised pollen mass filter deposition measurements, indicated that the EFSA Panel model had underestimated pollen deposition and, hence, exposure of non-target organisms to Bt-maize pollen. The results implied a need for safety buffer distances in the kilometre range for protected nature reserve areas instead of the 20-30 m range recommended by the EFSA Panel. As a result, the EFSA Panel revised their model (EFSA EFSA J 13: 4127, 4), adopting the slope of the empirical data from Hofmann et al. The intercept, however, was substantially reduced to less than 1% at one point by introducing further assumptions based on the estimates of mainly panel members, citing possible 'uncertainty'. Hofmann et al. (Environ Sci Eur 28: 14, 3) published extensive empirical data regarding pollen deposition on leaves. These results were part of a larger 3-year study involving detailed measurements of pollen release, dispersal and deposition over the maize flowering period. The data collected in situ confirmed the previous predictions of Hofmann et al. (Environ Sci Eur 26: 24, 2). Mean levels and observed variability of pollen deposition on maize and four lepidopteran host plants exceeded the assumptions and disagreed with the conclusions of the EFSA Panel. The EFSA Panel reacted in a report (EFSA EFSA Supp Publ, 1) criticising the methods and outcomes of the two published studies of Hofmann et al. while reaffirming their original recommendations. We respond here point-by-point, showing that the critique is not justified. Based on our results on Urtica leaf pollen density, we confirm the need for specific environmental impact assessments for Bt-maize cultivation with respect to protected habitats within isolation buffer distances in the kilometre range.

What's Manifest in the History of SciTech: Reflections on The History Manifesto.

PubMed

Kevles, Daniel J

2016-06-01

Making nuts-and-bolts public policy is not--and never has been--the long suit of professional historians, but general historical work, whatever its durée, has done a good deal to shape discourse on public issues. Jo Guldi and David Armitage neglect that fact, as well as the opinion-shaping influence of history conveyed via nonprint media. They also ignore the large body of scholarship produced in all media during recent decades in the history of science, technology, and science-related medicine (SciTech), even though SciTech itself looms enormously large in the modern era as an instrument of national and international security, a driver of the economy, and a transformer of medicine, public health, and the environment. Much of this scholarship, even though of short durée, can illuminate salient contemporary issues, including innovation; patronage and practice; government and policy; imperialism and globalization; intellectual property; science and religion; and human rights, environment, energy, and disasters.

Distributed Scaffolding: Synergy in Technology-Enhanced Learning Environments

ERIC Educational Resources Information Center

Ustunel, Hale H.; Tokel, Saniye Tugba

2018-01-01

When technology is employed challenges increase in learning environments. Kim et al. ("Sci Educ" 91(6):1010-1030, 2007) presented a pedagogical framework that provides a valid technology-enhanced learning environment. The purpose of the present design-based study was to investigate the micro context dimension of this framework and to…

Dynamic mechanical characterization of aluminum: analysis of strain-rate-dependent behavior

NASA Astrophysics Data System (ADS)

Rahmat, Meysam

2018-05-01

A significant number of materials show different mechanical behavior under dynamic loads compared to quasi-static (Salvado et al. in Prog. Mater. Sci. 88:186-231, 2017). Therefore, a comprehensive study of material dynamic behavior is essential for applications in which dynamic loads are dominant (Li et al. in J. Mater. Process. Technol. 255:373-386, 2018). In this work, aluminum 6061-T6, as an example of ductile alloys with numerous applications including in the aerospace industry, has been studied under quasi-static and dynamic tensile tests with strain rates of up to 156 s^{-1}. Dogbone specimens were designed, instrumented and tested with a high speed servo-hydraulic load frame, and the results were validated with the literature. It was observed that at a strain rate of 156 s^{-1} the yield and ultimate strength increased by 31% and 33% from their quasi-static values, respectively. Moreover, the failure elongation and fracture energy per unit volume also increased by 18% and 52%, respectively. A Johnson-Cook model was used to capture the behavior of the material at different strain rates, and a modified version of this model was presented to enhance the capabilities of the original model, especially in predicting material properties close to the failure point. Finally, the fracture surfaces of specimens tested under quasi-static and dynamic loads were compared and conclusions about the differences were drawn.

Measurement of acoustic velocity components in a turbulent flow using LDV and high-repetition rate PIV

NASA Astrophysics Data System (ADS)

Léon, Olivier; Piot, Estelle; Sebbane, Delphine; Simon, Frank

2017-06-01

The present study provides theoretical details and experimental validation results to the approach proposed by Minotti et al. (Aerosp Sci Technol 12(5):398-407, 2008) for measuring amplitudes and phases of acoustic velocity components (AVC) that are waveform parameters of each component of velocity induced by an acoustic wave, in fully turbulent duct flows carrying multi-tone acoustic waves. Theoretical results support that the turbulence rejection method proposed, based on the estimation of cross power spectra between velocity measurements and a reference signal such as a wall pressure measurement, provides asymptotically efficient estimators with respect to the number of samples. Furthermore, it is shown that the estimator uncertainties can be simply estimated, accounting for the characteristics of the measured flow turbulence spectra. Two laser-based measurement campaigns were conducted in order to validate the acoustic velocity estimation approach and the uncertainty estimates derived. While in previous studies estimates were obtained using laser Doppler velocimetry (LDV), it is demonstrated that high-repetition rate particle image velocimetry (PIV) can also be successfully employed. The two measurement techniques provide very similar acoustic velocity amplitude and phase estimates for the cases investigated, that are of practical interest for acoustic liner studies. In a broader sense, this approach may be beneficial for non-intrusive sound emission studies in wind tunnel testings.

A study on the maximum power transfer condition in an inductively coupled plasma using transformer circuit model

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kim, Young-Do; Lee, Hyo-Chang; Chung, Chin-Wook

Correlations between the external discharge parameters (the driving frequency ω and the chamber dimension R) and plasma characteristics (the skin depth δ and the electron-neutral collision frequency ν{sub m}) are studied using the transformer circuit model [R. B. Piejak et al., Plasma Sources Sci. Technol. 1, 179 (1992)] when the absorbed power is maximized in an inductively coupled plasma. From the analysis of the transformer circuit model, the maximum power transfer conditions, which depend on the external discharge parameters and the internal plasma characteristics, were obtained. It was found that a maximum power transfer occurs when δ≈0.38R for the dischargemore » condition at which ν{sub m}/ω≪1, while it occurs when δ≈√(2)√(ω/ν{sub m})R for the discharge condition at which ν{sub m}/ω≫1. The results of this circuit analysis are consistent with the stable last inductive mode region of an inductive-to-capacitive mode transition [Lee and Chung, Phys. Plasmas 13, 063510 (2006)], which was theoretically derived from Maxwell's equations. Our results were also in agreement with the experimental results. From this work, we demonstrate that a simple circuit analysis can be applied to explain complex physical phenomena to a certain extent.« less

Scintillator based detector for fast-ion losses induced by magnetohydrodynamic instabilities in the ASDEX upgrade tokamak.

PubMed

García-Muñoz, M; Fahrbach, H-U; Zohm, H

2009-05-01

A scintillator based detector for fast-ion losses has been designed and installed on the ASDEX upgrade (AUG) tokamak [A. Herrmann and O. Gruber, Fusion Sci. Technol. 44, 569 (2003)]. The detector resolves in time the energy and pitch angle of fast-ion losses induced by magnetohydrodynamics (MHD) fluctuations. The use of a novel scintillator material with a very short decay time and high quantum efficiency allows to identify the MHD fluctuations responsible for the ion losses through Fourier analysis. A Faraday cup (secondary scintillator plate) has been embedded behind the scintillator plate for an absolute calibration of the detector. The detector is mounted on a manipulator to vary its radial position with respect to the plasma. A thermocouple on the inner side of the graphite protection enables the safety search for the most adequate radial position. To align the scintillator light pattern with the light detectors a system composed by a lens and a vacuum-compatible halogen lamp has been allocated within the detector head. In this paper, the design of the scintillator probe, as well as the new technique used to analyze the data through spectrograms will be described. A last section is devoted to discuss the diagnosis prospects of this method for ITER [M. Shimada et al., Nucl. Fusion 47, S1 (2007)].

Characterization of Reaerosolization From Impingers in an Effort to Improve Airborne Virus Sampling

DTIC Science & Technology

2009-04-01

Koutrakis, P. (1996) Inertial separation of ultrafine particles using a condensational growth/ virtual impaction system. Aerosol Sci. Tech. 25, 424–436...Environ. 42, 828–832. Demokritou, P., Gupta, T., and and Koutrakis, P. (2002) A high volume apparatus for the condensational growth of ultrafine ... particles for inhalation toxicological studies. Aerosol Sci. Tech. 36, 1061–1072. Floyd, R., and Sharp, D. G. (1978) Viral aggregation: Effects of salts

Regional-scale simulation of transport and transformations of semi-volatile polycyclic aromatic hydrocarbons (PAHs) in East Asia: diurnal variations investigation

NASA Astrophysics Data System (ADS)

Mu, Qing; Lammel, Gerhard; Cheng, Yafang

2015-04-01

Semi-volatile PAHs are major pollutants of urban air, mostly regionally transported and reaching remote environments[1]. Some semi-volatile PAHs are carcinogenic. About 22% of global PAHs emissions are in China. The transport and sinks (atmospheric reactions, deposition) of semi-volatile PAHs in East Asia are studied using a modified version of the Weather Research and Forecasting model coupled with chemistry (WRF/Chem [2]). For this purpose, PAHs' gas and particulate phase chemical reactions and dry and wet deposition processes are included. We use emissions of 2008 [3] which include technical combustion processes (coal, oil, gas, waste and biomass) and open fires and apply diurnal time functions as those of black carbon. The model was run for phenanthrene (3-ring PAH, p = 1.5×10-2 Pa at 298 K) and benzo(a)pyrene (5-ring PAH, p = 7×10-7 Pa) for July 2013 with hourly output and 27 km horizontal grid spacing. The comparison of model predicted phenanthrene concentrations with measurements at a rural site near Beijing (own data, unpublished) validates the model's ability to simulate diurnal variations of gaseous PAHs. The model's performance is better in simulating day time than night time gaseous PAHs. The concentrations of PAHs had experienced significant diurnal variations in rural and remote areas of China. Elevated concentration levels of 40-60 ng m-3 for phenanthrene and 1-10 ng m-3 for benzo(a)pyrene are predicted in Shanxi, Guizhou, the North China Plain, the Sichuan Basin and Chongqing metropolitan areas due to the high emission densities at those locations. References [1] Keyte, I.J., Harrison, R.M., and Lammel, G., 2013: Chemical reactivity and long-range transport potential of polycyclic aromatic hydrocarbons - a review, Chem. Soc. Rev., 42, 9333-9391. [2] Grell, G.A, Peckham, S.E, Schmitz, R, McKeen, S.A, Frost, G, Skamarock, W.C, and Eder, B., 2005: Fully coupled online chemistry within the WRF model, Atmos. Environ., 39, 6957-6975. [3] Shen, H. Z., Huang, Y., Wang, R., Zhu, D., Li, W., Shen, G. F., Wang, B., Zhang, Y. Y., Chen, Y. C., Lu, Y., Chen, H., Li, T. C., Sun, K., Li, B. G., Liu, W. X., Liu, J. F., and Tao, S., 2013: Global atmospheric emissions of polycyclic aromatic hydrocarbons from 1960 to 2008 and future predictions, Environ. Sci. Technol., 47, 6415-6424.

Primary VOC emissions from Commercial Aircraft Jet Engines

NASA Astrophysics Data System (ADS)

Kilic, Dogushan; Huang, Rujin; Slowik, Jay; Brem, Benjamin; Durdina, Lukas; Rindlisbacher, Theo; Baltensperger, Urs; Prevot, Andre

2014-05-01

Air traffic is growing continuously [1]. The increasing number of airplanes leads to an increase of aviation emissions giving rise to environmental concerns globally by high altitude emissions and, locally on air quality at the ground level [2]. The overall impact of aviation emissions on the environment is likely to increase when the growing air transportation trend [2] is considered. The Aviation Particle Regulatory Instrumentation Demonstration Experiment (APRIDE)-5 campaign took place at Zurich Airport in 2013. In this campaign, aircraft exhaust is sampled during engine acceptance tests after engine overhaul at the facilities of SR Technics. Direct sampling from the engine core is made possible due to the unique fixed installation of a retractable sampling probe and the use of a standardized sampling system designed for the new particulate matter regulation in development for aircraft engines. Many of the gas-phase aircraft emissions, e.g. CO2, NOX, CO, SO2, hydrocarbons, and volatile organic compounds (VOC) were detected by the instruments in use. This study, part of the APRIDE-5 campaign, focuses on the primary VOC emissions in order to produce emission factors of VOC species for varying engine operating conditions which are the surrogates for the flight cycles. Previously, aircraft plumes were sampled in order to quantify VOCs by a proton transfer reaction quadrupole mass spectrometer (PTR-MS) [3]. This earlier study provided a preliminary knowledge on the emission of species such as methanol, acetaldehyde, acetone, benzene and toluene by varying engine thrust levels. The new setup was (i) designed to sample from the diluted engine exhaust and the new tool and (ii) used a high resolution time of flight PTR-MS with higher accuracy for many new species, therefore providing a more detailed and accurate inventory. We will present the emission factors for species that were quantified previously, as well as for many additional VOCs detected during the campaign. References 1."Annual Review 2013", International Air Transport Association (IATA) 2014, Page 8, available on: http://www.iata.org/about/Documents/iata-annual-review-2013-en.pdf. 2."Summary for Policymakers: IPCC Special Report Aviation and the Global Atmosphere", 1999, pp. 5-10. 3."Hydrocarbon emissions from in-use commercial aircraft during airport operations", Herndon S.C., Rogers T., Dunlea E.J., Jayne J.T., Miake-Lye R., Knighton B., Environ Sci. Technol. 2006 Jul 15;40(14):4406-13.

Global burden of mortalities due to chronic exposure to ambient PM2.5 from open combustion of domestic waste

NASA Astrophysics Data System (ADS)

Kodros, John K.; Wiedinmyer, Christine; Ford, Bonne; Cucinotta, Rachel; Gan, Ryan; Magzamen, Sheryl; Pierce, Jeffrey R.

2016-12-01

Uncontrolled combustion of domestic waste has been observed in many countries, creating concerns for air quality; however, the health implications have not yet been quantified. We incorporate the Wiedinmyer et al (2014 Environ. Sci. Technol. 48 9523-30) emissions inventory into the global chemical-transport model, GEOS-Chem, and provide a first estimate of premature adult mortalities from chronic exposure to ambient PM2.5 from uncontrolled combustion of domestic waste. Using the concentration-response functions (CRFs) of Burnett et al (2014 Environ. Health Perspect. 122 397-403), we estimate that waste-combustion emissions result in 270 000 (5th-95th: 213 000-328 000) premature adult mortalities per year. The confidence interval results only from uncertainty in the CRFs and assumes equal toxicity of waste-combustion PM2.5 to all other PM2.5 sources. We acknowledge that this result is likely sensitive to choice of chemical-transport model, CRFs, and emission inventories. Our central estimate equates to 9% of adult mortalities from exposure to ambient PM2.5 reported in the Global Burden of Disease Study 2010. Exposure to PM2.5 from waste combustion increases the risk of premature mortality by more than 0.5% for greater than 50% of the population. We consider sensitivity simulations to uncertainty in waste-combustion emission mass, the removal of waste-combustion emissions, and model resolution. A factor-of-2 uncertainty in waste-combustion PM2.5 leads to central estimates ranging from 138 000 to 518 000 mortalities per year for factors-of-2 reductions and increases, respectively. Complete removal of waste combustion would only avoid 191 000 (5th-95th: 151 000-224 000) mortalities per year (smaller than the total contributed premature mortalities due to nonlinear CRFs). Decreasing model resolution from 2° × 2.5° to 4° × 5° results in 16% fewer mortalities attributed to waste-combustion PM2.5, and over Asia, decreasing resolution from 0.5° × 0.666° to 2° × 2.5° results in 21% fewer mortalities attributed to waste-combustion PM2.5. Owing to coarse model resolution, our global estimates of premature mortality from waste-combustion PM2.5 are likely a lower bound.

Temporal change in the size distribution of airborne Radiocesium derived from the Fukushima accident

NASA Astrophysics Data System (ADS)

Kaneyasu, Naoki; Ohashi, Hideo; Suzuki, Fumie; Okuda, Tomoaki; Ikemori, Fumikazu; Akata, Naofumi

2013-04-01

The accident of Fukushima Dai-ichi nuclear power plant discharged a large amount of radioactive materials into the environment. After 40 days of the accident, we started to collect the size-segregated aerosol at Tsukuba City, Japan, located 170 km south of the plant, by use of a low-pressure cascade impactor. The sampling continued from April 28, through October 26, 2011. The number of sample sets collected in total was 8. The radioactivity of 134Cs and 137Cs in aerosols collected at each stage were determined by gamma-ray with a high sensitivity Germanic detector. After the gamma-ray spectrometry analysis, the chemical species in the aerosols were analyzed. The analyses of first (April 28-May 12) and second (May 12-26) samples showed that the activity size distributions of 134Cs and 137Cs in aerosols reside mostly in the accumulation mode size range. These activity size distributions almost overlapped with the mass size distribution of non-sea-salt sulfate aerosol. From the results, we regarded that sulfate is the main transport medium of these radionuclides, and re-suspended soil particles that attached radionuclides were not the major airborne radioactive substances by the end of May, 2011 (Kaneyasu et al., 2012). We further conducted the successive extraction experiment of radiocesium from the aerosol deposits on the aluminum sheet substrate (8th stage of the first aerosol sample, 0.5-0.7 μm in aerodynamic diameter) with water and 0.1M HCl. In contrast to the relatively insoluble property of Chernobyl radionuclides, those in aerosols collected at Tsukuba in fine mode are completely water-soluble (100%). From the third aerosol sample, the activity size distributions started to change, i.e., the major peak in the accumulation mode size range seen in the first and second aerosol samples became smaller and an additional peak appeared in the coarse mode size range. The comparison of the activity size distributions of radiocesium and the mass size distributions of major aerosol components collected by the end of August, 2011, (i.e., sample No.5) and its implication will be discussed in the presentation. Reference Kaneyasu et al., Environ. Sci. Technol. 46, 5720-5726 (2012).

Novel Applications of Peroxidase

NASA Astrophysics Data System (ADS)

Rob, Abdul; Ball, Andrew S.; Tuncer, Munir; Wilson, Michael T.

1997-02-01

The article entitled "Novel Biocatalysts Will Work Even Better for Industry" published recently in this Journal (1) was informative and interesting. However it touched only briefly on the application of peroxidase as catalyst. Here, we would like to mention in more detail the novel applications of peroxidase in agricultural, paper pulp, water treatment, pharmaceutical, and medical situations. Firstly, the peroxidase isolated from Phanerochaete chyrosporium has been shown to detoxify herbicides such as atrazine to less toxic compounds and would certainly find potential application in agriculture (2). Secondly, the peroxidase produced by Streptomyces thermoviolaceus may find application in the paper pulp industry as a delignifying agent (3). Thirdly, it has been shown that extracellular peroxidase produced by Streptomyces avermitilis can remove the intense color from paper-mill effluent obtained after semichemical alkaline pulping of wheat straw (4), and thus this enzyme might find application as a catalyst in water treatment plants. Fourthly, the heme-containing horseradish peroxidase enzyme has been exploited in several diagnostic applications in pharmaceutics and medicine, such as the detection of human immunodeficiency virus and cystic fibrosis (5-10). Finally, recent work from our laboratory has suggested that thermophilic nonheme peroxidase produced by Thermomonospora fusca BD25 may find medical use in the diagnosis of myocardial infarction (11, 12). Literature Cited 1. Wiseman, A. J. Chem. Educ. 1996, 73, 55-58. 2. Mougin, C. Appl. Environ. Microbiol. 1994, 60, 705-708. 3. McCarthy A. J.; Peace, W.; Broda, P. Appl. Microbiol. Technol. 1985, 23, 238-244. 4. Hernandez, M; Rodriguez J; Soliveri, J; Copa, J. L; Perez, M. I; Arias, M. E. Appl. Environ. Microbiol. 1994, 60, 3909-3913. 5. Hopfer, S. M.; Aslanzadeh, J. Ann. Clin. Lab. Sci. 1995, 25, 475-480. 6. Suzuki, K; Iman, M. J. Virol. Methods 1995, 55, 347-356. 7. Nielsen, K. J. Immunoassay 1995, 16, 183-197. 8. Warhol, M. J.; Heitz, P. U. Lab. Invest. 1992, 67, 263-269. 9. Pergande, M.; Jung, K. Clin. Chem. 1993, 39, 1885-1890. 10. Allain, C. C; Poon, L. S.; Chan, C. S. G; Richmond, W.; Fu, P. C. Clin. Chem. 1974, 20, 470-475. 11. Rob, A; Ball, A. S.; Tuncer, M; Wilson, M. T. Biochem. Soc. Trans. 1995, 23, 507. 12. Rob, A.; Ball, A. S.; Tuncer, M.; Jones, G. D.; Taylor, P. D; Wilson, M. T. Biochem. Soc. Trans. 1996, 24, 455.

The Impact of Health Behaviors and Health Management on Employment After SCI: Physical Health and Functioning.

PubMed

Meade, Michelle A; Reed, Karla S; Krause, James S

2016-01-01

Background : Research has shown that employment following spinal cord injury (SCI) is related to health and functioning, with physical health and functioning after SCI frequently identified as a primary barrier to employment. Objective: To examine the relationship between employment and behaviors associated with the management of physical health and functioning as described by individuals with SCI who have been employed post injury. Methods: A qualitative approach using 6 focus groups at 2 sites included 44 participants with SCI who had worked at some time post injury. Heterogeneous and homogeneous groups were created based on specific characteristics, such as education, gender, or race. A semi-structured interview format asked questions about personal, environmental, and policy-related factors influencing employment after SCI. Groups were recorded, transcribed, and entered into NVivo before coding by 2 reviewers. Results: Within the area of behaviors and management of physical health and functioning, 4 overlapping themes were identified: (1) relearning your own body and what it can do; (2) general health and wellness behaviors; (3) communication, education, and advocacy; and (4) secondary conditions and aging. Specific themes articulate the many types of behaviors individuals must master and their impact on return to work as well as on finding, maintaining, and deciding to leave employment. Conclusions: Individuals with SCI who are successfully employed after injury must learn how to perform necessary behaviors to manage health and function in a work environment. The decision to leave employment often appears to be associated with secondary complications and other conditions that occur as persons with SCI age.

Differences in the Community Built Environment Influence Poor Perceived Health among Persons with Spinal Cord Injury

PubMed Central

Botticello, Amanda L.; Rohrbach, Tanya; Cobbold, Nicolette

2015-01-01

Objectives To assess the association between characteristics of the built environment and differences in perceived health among persons with spinal cord injury (SCI) using objective measures of the local community derived from Geographic Information Systems (GIS) data. Design Secondary analysis of cross-sectional survey data. Setting Community. Participants 503 persons with chronic SCI enrolled in the Spinal Cord Injury Model Systems (SCIMS) database. All cases were residents of New Jersey, completed an interview during the years 2000–2012, had a complete residential address, and were community living at the time of follow-up. Intervention Not applicable. Main Outcome Measure Perceived health. Results Bivariate tests indicated that persons with SCI residing in communities with more (versus less) mixed land use and small (versus large) amounts of open space were more likely to report poor perceived health. No associations were found between perceived health and differences in the residential or destination density of the community. Adjusting for variation in demographic, impairment, quality of life, and community socioeconomic characteristics accounted for the gap in the odds of reporting poor health between persons living in areas with large versus small amounts of open space (OR 0.54; 95% CI 0.28–1.02). However, even after accounting for individual background differences, persons living in communities characterized by more heterogeneous land use were twice as likely to report poor health compared to persons living in less mixed areas (OR 2.14; 95% CI 1.12–4.08). Conclusions Differences in the built characteristics of communities may be important to the long-term health and well-being of persons with SCI who may have greater exposure to the features of their local area due to limited mobility. The results of this study suggest living in a community with more heterogeneous land use was not beneficial to the perceived health of persons with chronic SCI living in New Jersey. Further investigation is needed to assess if the relationships observed in this analysis are influenced by differences in infrastructure and resources across communities. Further research is also needed to investigate the role built environment plays in the long-term health and well-being of persons with SCI in other geographic locales. PMID:25998221

Differences in the Community Built Environment Influence Poor Perceived Health Among Persons With Spinal Cord Injury.

PubMed

Botticello, Amanda L; Rohrbach, Tanya; Cobbold, Nicolette

2015-09-01

To assess the association between characteristics of the built environment and differences in perceived health among persons with spinal cord injury (SCI) using objective measures of the local community derived from Geographic Information Systems data. Secondary analysis of cross-sectional survey data. Community. Persons with chronic SCI enrolled in the Spinal Cord Injury Model Systems database (N=503). All cases were residents of New Jersey, completed an interview during the years 2000 through 2012, had a complete residential address, and were community living at the time of follow-up. Not applicable. Perceived health. Bivariate tests indicated that persons with SCI residing in communities with more (vs less) mixed land use and small (vs large) amounts of open space were more likely to report poor perceived health. No associations were found between perceived health and differences in the residential or destination density of the community. Adjusting for variation in demographic, impairment, quality of life, and community socioeconomic characteristics accounted for the gap in the odds of reporting poor health between persons living in areas with large versus small amounts of open space (odds ratio [OR], 0.54; 95% confidence interval [CI], 0.28-1.02). However, even after accounting for individual background differences, persons living in communities characterized by more heterogeneous land use were twice as likely to report poor health compared with persons living in less mixed areas (OR, 2.14; 95% CI, 1.12-4.08). Differences in the built characteristics of communities may be important to the long-term health and well-being of persons with SCI who may have greater exposure to the features of their local area because of limited mobility. The results of this study suggest living in a community with more heterogeneous land use was not beneficial to the perceived health of persons with chronic SCI living in New Jersey. Further investigation is needed to assess if the relationships observed in this analysis are influenced by differences in infrastructure and resources across communities. Further research is also needed to investigate the role built environment plays in the long-term health and well-being of persons with SCI in other geographic locales. Copyright © 2015 American Congress of Rehabilitation Medicine. Published by Elsevier Inc. All rights reserved.

Aerosol volatility in a boreal forest environment

NASA Astrophysics Data System (ADS)

Häkkinen, S. A. K.; ńijälä, M.; Lehtipalo, K.; Junninen, H.; Virkkula, A.; Worsnop, D. R.; Kulmala, M.; Petäjä, T.; Riipinen, I.

2012-04-01

Climate and health effects of atmospheric aerosols are determined by their properties such as their chemical composition. Aerosol chemical composition can be studied indirectly by measuring volatility of aerosol particles. The volatility of submicron aerosol particles (20-500 nm) was studied in a boreal forest site at SMEAR II (Station for Measuring Ecosystem-Atmosphere Relations II) station (Vesala et al., 1998) in Hyytiälä, Finland, during 01/2008-05/2010. The instrument used for the measurements was VDMPS (Volatility Differential Mobility Particle Sizer), which consists of two separate instruments: DMPS (Differential Mobility Particle Sizer, Aalto et al., 2001) and TD (Thermodenuder, Wehner et al., 2002). Aerosol evaporation was examined by heating the aerosol and comparing the total aerosol mass before and after heating. In the VDMPS system ambient aerosol sample was heated up to temperatures ranging from 80 °C to 280 °C. The higher the heating temperature was the more aerosol material was evaporated. There was a non-volatile residual present in aerosol particles when heated up to 280 °C. This residual explained (20±8)% of the total aerosol mass. Aerosol non-volatile mass fraction was highest during winter and smallest during summer months. The role of black carbon in the observed non-volatile residual was determined. Black carbon explained 40 to 90% of the non-volatile mass. Especially during colder seasons noticeable amount of non-volatile material, something else than black carbon, was observed. According to Kalberer et al. (2004) some atmospheric organic species can form polymers that have high evaporation temperatures. Also low-volatile organic salts may contribute to the non-volatile aerosol (Smith et al., 2010). Aerosol mass composition measured directly with AMS (Aerosol Mass Spectrometer, Jayne et al., 2000) was analyzed in order to examine the properties of the non-volatile material (other than black carbon). The AMS measurements were performed during spring and autumn 2008. Results from the aerosol mass spectrometry indicate that the non-volatile residual consists of nitrate and organic compounds, especially during autumn. These compounds may be low-volatile organic nitrates or salts. During winter and spring the non-volatile core (black carbon removed) correlated markedly with carbon monoxide, which is a tracer of anthropogenic emissions. Due to this, the non-volatile residual may also contain other pollutants in addition to black carbon. Thus, it seems that the amount of different compounds in submicron aerosol particles varies with season and as a result the chemical composition of the non-volatile residual changes within a year. This work was supported by University of Helsinki three-year research grant No 490082 and Maj and Tor Nessling Foundation grant No 2010143. Aalto et al., (2001). Physical characterization of aerosol particles during nucleation events. Tellus B, 53, 344-358. Jayne, et al., (2000). Development of an aerosol mass spectrometer for size and composition analysis of submicron particles. Aerosol Sci. Technol., 33(1-2), 49-70. Kalberer et al., (2004). Identification of Polymers as Major Components of Atmospheric Organic Aerosols. Science, 303, 1659-1662. Smith et al., (2010). Observations of aminium salts in atmospheric nanoparticles and possible climatic implications. P. Natl. Acad. Sci., 107(15). Vesala et al., (1998). Long-term field measurements of atmosphere-surface interactions in boreal forest combining forest ecology, micrometeorology, aerosol physics and atmospheric chemistry. Trends Heat, Mass Mom. Trans., 4, 17-35. Wehner et al., (2002). Design and calibration of a thermodenuder with an improved heating unit to measure the size-dependent volatile fraction of aerosol particles. J. Aerosol Sci., 33, 1087-1093.

Effect of chemical environment and rock composition on fracture mechanics properties of reservoir lithologies in context of CO2 sequestration

NASA Astrophysics Data System (ADS)

Major, J. R.; Eichhubl, P.; Callahan, O. A.

2015-12-01

The coupled chemical and mechanical response of reservoir and seal rocks to injection of CO2 have major implications on the short and long term security of sequestered carbon. Many current numerical models evaluating behavior of reservoirs and seals during and after CO2 injection in the subsurface consider chemistry and mechanics separately and use only simple mechanical stability criteria while ignoring time-dependent failure parameters. CO2 injection irreversibly alters the subsurface chemical environment which can then affect geomechanical properties on a range of time scales by altering rock mineralogy and cements through dissolution, remobilization, and precipitation. It has also been documented that geomechanical parameters such as fracture toughness (KIC) and subcritical index (SCI) are sensitive to chemical environment. Double torsion fracture mechanics testing of reservoir lithologies under controlled environmental conditions relevant to CO2 sequestration show that chemical environment can measurably affect KIC and SCI. This coupled chemical-mechanical behavior is also influenced by rock composition, grains, amount and types of cement, and fabric. Fracture mechanics testing of the Aztec Sandstone, a largely silica-cemented, subarkose sandstone demonstrate it is less sensitive to chemical environment than Entrada Sandstone, a silty, clay-rich sandstone. The presence of de-ionized water lowers KIC by approximately 20% and SCI 30% in the Aztec Sandstone relative to tests performed in air, whereas the Entrada Sandstone shows reductions on the order of 70% and 90%, respectively. These results indicate that rock composition influences the chemical-mechanical response to deformation, and that the relative chemical reactivity of target reservoirs should be recognized in context of CO2 sequestration. In general, inert grains and cements such as quartz will be less sensitive to the changing subsurface environment than carbonates and clays.

Scytonemin Plays a Potential Role in Stabilizing the Exopolysaccharidic Matrix in Terrestrial Cyanobacteria.

PubMed

Gao, Xiang

2017-02-01

Cyanobacteria are photosynthetic oxygen-evolving prokaryotes that are distributed in diverse habitats. They synthesize the ultraviolet (UV)-screening pigments, scytonemin (SCY) and mycosporine-like amino acids (MAAs), located in the exopolysaccharide (EPS) matrix. Multiple roles for both pigments have gradually been recognized, such as sunscreen ability, antioxidant activity, and heat dissipation from absorbed UV radiation. In this study, a filamentous terrestrial cyanobacterium Nostoc flagelliforme was used to evaluate the potential stabilizing role of SCY on the EPS matrix. SCY (∼3.7 %) was partially removed from N. flagelliforme filaments by rinsing with 100 % acetone for 5 s. The physiological damage to cells resulting from this treatment, in terms of photosystem II activity parameter Fv/Fm, was repaired after culturing the sample for 40 h. The physiologically recovered sample was further desiccated by natural or rapid drying and then allowed to recovery for 24 h. Compared with the normal sample, a relatively slower Fv/Fm recovery was observed in the SCY-partially removed sample, suggesting that the decreased SCY concentration in the EPS matrix caused cells to suffer further damage upon desiccation. In addition, the SCY-partially removed sample could allow the release of MAAs (∼25 %) from the EPS matrix, while the normal sample did not. Therefore, damage caused by drying of the former resulted from at least the reduction of structural stability of the EPS matrix as well as the loss of partial antioxidant compounds. Considering that an approximately 4 % loss of SCY led to this significant effect, the structurally stabilizing potential of SCY on the EPS matrix is crucial for terrestrial cyanobacteria survival in complex environments.

A pilot study evaluating protein abundance in pressure ulcer fluid from people with and without spinal cord injury

PubMed Central

Edsberg, Laura E.; Wyffels, Jennifer T.; Ogrin, Rajna; Craven, B. Catharine; Houghton, Pamela

2015-01-01

Objective To determine whether the biochemistry of chronic pressure ulcers differs between patients with and without chronic spinal cord injury (SCI) through measurement and comparison of the concentration of wound fluid inflammatory mediators, growth factors, cytokines, acute phase proteins, and proteases. Design Survey. Setting Tertiary spinal cord rehabilitation center and skilled nursing facilities. Participants Twenty-nine subjects with SCI and nine subjects without SCI (>18 years) with at least one chronic pressure ulcer Stage II, III, or IV were enrolled. Outcome measures Total protein and 22 target analyte concentrations including inflammatory mediators, growth factors, cytokines, acute phase proteins, and proteases were quantified in the wound fluid and blood serum samples. Blood samples were tested for complete blood count, albumin, hemoglobin A1c, total iron binding capacity, iron, percent (%) saturation, C-reactive protein, and erythrocyte sedimentation rate. Results Wound fluid concentrations were significantly different between subjects with SCI and subjects without SCI for total protein concentration and nine analytes, MMP-9, S100A12, S100A8, S100A9, FGF2, IL-1b, TIMP-1, TIMP-2, and TGF-b1. Subjects without SCI had higher values for all significantly different analytes measured in wound fluid except FGF2, TGF-b1, and wound fluid total protein. Subject-matched circulating levels of analytes and the standardized local concentration of the same proteins in the wound fluid were weakly or not correlated. Conclusions The biochemical profile of chronic pressure ulcers is different between SCI and non-SCI populations. These differences should be considered when selecting treatment options. Systemic blood serum properties may not represent the local wound environment. PMID:24968005

Environmental factors and their role in community integration after spinal cord injury.

PubMed

Lysack, Cathy; Komanecky, Marie; Kabel, Allison; Cross, Katherine; Neufeld, Stewart

2007-01-01

The International Classification of Functioning, Disability and Health (ICF) model presents an opportunity to better understand previously neglected longterm social outcomes after traumatic spinal cord injury (SCI), especially the experience of participation. The study explored the relationship between perceived environmental barriers and perceived community integration (a participation proxy) in a sample of adults with traumatic SCI. The study interviewed African American and White women and men (n = 136) who had lived with SCI for an average of 11.5 years. Participants reported environmental barriers at twice the level indicated by previous studies; the natural environment and the policies of government were the most problematic. Levels of community integration were also high. Data suggest a significant relationship (p < .01) between perceived environmental barriers and community integration for adults with SCI, providing support for the ICF model. Improved measures and more sophisticated concepts and theories are needed to explicate the relationship between environmental factors and participation concepts in the ICE With respect to practice, occupational therapists need to be aware that removal of environmental barriers is only a first step in the more complex effort to facilitate optimal community integration after SCI.

SciJourn is magic: construction of a science journalism community of practice

NASA Astrophysics Data System (ADS)

Nicholas, Celeste R.

2017-06-01

This article is the first to describe the discoursal construction of an adolescent community of practice (CoP) in a non-school setting. CoPs can provide optimal learning environments. The adolescent community centered around science journalism and positioned itself dichotomously in relationship to school literacy practices. The analysis focuses on recordings from a panel-style research interview from an early implementation of the Science Literacy Through Science Journalism (SciJourn) project. Researchers trained high school students participating in a youth development program to write science news articles. Students engaged in the authentic practices of professional science journalists, received feedback from a professional editor, and submitted articles for publication. I used a fine-grained critical discourse analysis of genre, discourse, and style to analyze student responses about differences between writing in SciJourn and in school. Students described themselves as agentic in SciJourn and passive in school, using an academic writing discourse of deficit to describe schooling experiences. They affiliated with and defined a SciJourn CoP, constructing positive journalistic identities therein. Educators are encouraged to develop similar CoPs. The discursive features presented may be used to monitor the development of communities of practice in a variety of settings.

Regenerative Potential of Ependymal Cells for Spinal Cord Injuries Over Time.

PubMed

Li, Xiaofei; Floriddia, Elisa M; Toskas, Konstantinos; Fernandes, Karl J L; Guérout, Nicolas; Barnabé-Heider, Fanie

2016-11-01

Stem cells have a high therapeutic potential for the treatment of spinal cord injury (SCI). We have shown previously that endogenous stem cell potential is confined to ependymal cells in the adult spinal cord which could be targeted for non-invasive SCI therapy. However, ependymal cells are an understudied cell population. Taking advantage of transgenic lines, we characterize the appearance and potential of ependymal cells during development. We show that spinal cord stem cell potential in vitro is contained within these cells by birth. Moreover, juvenile cultures generate more neurospheres and more oligodendrocytes than adult ones. Interestingly, juvenile ependymal cells in vivo contribute to glial scar formation after severe but not mild SCI, due to a more effective sealing of the lesion by other glial cells. This study highlights the importance of the age-dependent potential of stem cells and post-SCI environment in order to utilize ependymal cell's regenerative potential. Copyright © 2016 The Authors. Published by Elsevier B.V. All rights reserved.

A faster and more reliable data acquisition system for the full performance of the SciCRT

DOE PAGES

Sasai, Y.; Matsubara, Y.; Itow, Y.; ...

2017-01-03

The SciBar Cosmic Ray Telescope (SciCRT) is a massive scintillator tracker to observe cosmic rays at a very high-altitude environment in Mexico. The fully active tracker is based on the Scintillator Bar (SciBar) detector developed as a near detector for the KEK-to-Kamioka long-baseline neutrino oscillation experiment (K2K) in Japan. Since the data acquisition (DAQ) system was developed for the accelerator experiment, we determined to develop a new robust DAQ system to optimize it to our cosmic-ray experiment needs at the top of Mt. Sierra Negra (4600 m). One of our special requirements is to achieve a 10 times faster readoutmore » rate. We started to develop a new fast readout back-end board (BEB) based on 100 Mbps SiTCP, a hardware network processor developed for DAQ systems for high energy physics experiments. Then we developed the new BEB which has a potential of 20 times faster than the current one in the case of observing neutrons. Lastly, we installed the new DAQ system including the new BEBs to a part of the SciCRT in July 2015. The system has been operating since then. In this article, we describe the development, the basic performance of the new BEB, the status after the installation in the SciCRT, and the future performance.« less

Life cycle assessment in support of sustainable transportation

NASA Astrophysics Data System (ADS)

Eckelman, Matthew J.

2013-06-01

In our rapidly urbanizing world, sustainable transportation presents a major challenge. Transportation decisions have considerable direct impacts on urban society, both positive and negative, for example through changes in transit times and economic productivity, urban connectivity, tailpipe emissions and attendant air quality concerns, traffic accidents, and noise pollution. Much research has been dedicated to quantifying these direct impacts for various transportation modes. Transportation planning decisions also result in a variety of indirect environmental and human health impacts, a portion of which can accrue outside of the transit service area and so outside of the local decision-making process. Integrated modeling of direct and indirect impacts over the life cycle of different transportation modes provides decision support that is more comprehensive and less prone to triggering unintended consequences than a sole focus on direct tailpipe emissions. The recent work of Chester et al (2013) in this journal makes important contributions to this research by examining the environmental implications of introducing bus rapid transit and light rail in Los Angeles using life cycle assessment (LCA). Transport in the LA region is dominated by automobile trips, and the authors show that potential shifts to either bus or train modes would reduce energy use and emissions of criteria air pollutants, on an average passenger mile travelled basis. This work compares not just the use of each vehicle, but also upstream impacts from its manufacturing and maintenance, as well as the construction and maintenance of the entire infrastructure required for each mode. Previous work by the lead author (Chester and Horvath 2009), has shown that these non-operational sources and largely non-local can dominate life cycle impacts from transportation, again on an average (or attributional) basis, for example increasing rail-related GHG emissions by >150% over just operational emissions. While average results are valuable in comparing transport modes generally, they are less representative of local planning decisions, where the focus is on understanding the consequences of new infrastructure and how it might affect traffic, community impacts, and environmental aspects going forward. Chester et al (2013) also present their results using consequential LCA, which provides more detailed insights about the marginal effects of the specific rapid bus and light rail lines under study. The trade-offs between the additional resources required to install the public transit infrastructure (the 'resource debt') and the environmental advantages during the operation of these modes can be considered explicitly in terms of environmental impact payback periods, which vary with the type of environmental impact being considered. For example, bus rapid transit incurs a relatively small carbon debt associated with the GHG emissions of manufacturing new buses and installing transit infrastructure and pays this debt off almost immediately, while it takes half a century for the light rail line to pay off the 'smog debt' of its required infrastructure. This payback period approach, ubiquitous in life cycle costing, has been useful for communicating the magnitude of unintended environmental consequences from other resource and land management decisions, e.g., the release of soil carbon from land conversion to bioenergy crops (Fargione et al 2008), and will likely grow in prevalence as consequential LCA is used for decision support. The locations of projected emissions is just as important to decision-making as their magnitudes, as policy-making bodies seek to understand effects in their jurisdictions; however, life cycle impact assessment methods typically aggregate results by impact category rather than by source or sink location. Chester et al (2013) address this issue by providing both local (within Los Angeles) and total emissions results, with accompanying local-only payback periods. Much more challenging is the geographic mapping of impacts that these emissions will cause, given the many point and mobile sources of air pollutants over the entire transportation life cycle. Integration of LCA with high-resolution data sets is an active area of model development (Mutel and Hellweg 2009) and will provide site- and population-specific information for impacts ranging from water quality to biodiversity to human respiratory health. Another complex challenge in modeling environmental impacts of transportation (and cities in general) is the long run, interdependent relationship between transportation technologies and urban form. LCA modeling has tended to assume a fixed pattern of settlements and demand for mobility and then examined changes to a particular technology or practice within the transportation system, such as electric or hybrid vehicles or improved pavement materials. New transit options or other travel demand management strategies might induce mode switching or reduced trips, but the overall pattern of where people live and work is generally assumed in these models to be constant in the short run. In contrast, the automobile has been influencing land-use patterns for a century, and it is the resulting geographic structure that determines the baseline need for transportation, and thus drives the use of material and energy resources used in transportation systems (Kunstler 1994). We have seen that cities with high population densities tend to have lower tailpipe emissions from transportation (Kennedy et al 2009). Recent studies have modeled how changes in urban land-use or zoning changes the geographic structure of transportation demand and then used LCA to determine the environmental benefits of such policies. For example, Mashayekh et al (2012) summarized travel demand reductions projected from several studies of compact, smart growth, and brownfield in-fill development strategies to find benefits ranging up to 75% reductions in life cycle GHG and air pollutant emissions. A related study in Toronto on life cycle energy use and GHG emissions for high- and low-density development strategies found a ~60% difference in GHG emissions, largely due to transportation (Norman et al 2006). System dynamics and agent-based models may complement LCA in capturing long-term effects of transportation strategies as they are inherently dynamic (Stepp et al 2009), and can internalize spatially resolved decisions about where to settle and work (Waddell 2002). Transportation planning decisions have both direct and indirect, spatially distributed, often long-term effects on our health and our environment. The accompanying work by Chester et al (2013) provides a well-documented case study that highlights the potential of LCA as a rich source of decision support. References Chester M, Pincetl S, Elizabeth Z, Eisenstein W and Matute J 2013 Infrastructure and automobile shifts: positioning transit to reduce life-cycle environmental impacts for urban sustainability goals Environ. Res. Lett. 8 015041 Chester M V and Horvath A 2009 Environmental assessment of passenger transportation should include infrastructure and supply chains Environ. Res. Lett. 4 024008 Fargione J, Hill J, Tilman D, Polasky S and Hawthorne P 2008 Land clearing and the biofuel carbon debt Science 319 1235-8 Kennedy C, Steinberger J, Gasson B, Hansen Y, Hillman T, Havránek M, Pataki D, Phdungsilp A, Ramaswami A and Mendez G V 2009 Greenhouse gas emissions from global cities Environ. Sci. Technol. 43 7297-302 Kunstler J H 1994 Geography of Nowhere: The Rise and Decline of America's Man-Made Landscape (New York: Free Press) Mashayekh Y, Jaramillo P, Samaras C, Hendrickson C T, Blackhurst M, MacLean H L and Matthews H S 2012 Potentials for sustainable transportation in cities to alleviate climate change impacts Environ. Sci. Technol. 46 2529-37 Mutel C L and Hellweg S 2009 Regionalized life cycle assessment: computational methodology and application to inventory databases Environ. Sci. Technol. 43 5797-803 Norman J, MacLean H L and Kennedy C A 2006 Comparing high and low residential density: life-cycle analysis of energy use and greenhouse gas emissions J. Urban Plann. Dev. 132 10-21 Stepp M D, Winebrake J J, Hawker J S and Skerlos S J 2009 Greenhouse gas mitigation policies and the transportation sector: the role of feedback effects on policy effectiveness Energy Policy 37 2774-87 Waddell P 2002 UrbanSim: modeling urban development for land use, transportation, and environmental planning J. Am. Plann. Assoc. 68 297-314

Daniel J. Schell | NREL

Science.gov Websites

processing High solids biomass conversion Fermentation process development Separation processes Techno ; Bioresour. Technol. (2010) "An economic comparison of different fermentation configurations to convert

The strongest magnetic barrier in the DIII-D tokamak and comparison with the ASDEX UG

NASA Astrophysics Data System (ADS)

Ali, Halima; Punjabi, Alkesh

2013-05-01

Magnetic perturbations in tokamaks lead to the formation of magnetic islands, chaotic field lines, and the destruction of flux surfaces. Controlling or reducing transport along chaotic field lines is a key challenge in magnetically confined fusion plasmas. A local control method was proposed by Chandre et al. [Nucl. Fusion 46, 33-45 (2006)] to build barriers to magnetic field line diffusion by addition of a small second-order control term localized in the phase space to the field line Hamiltonian. Formation and existence of such magnetic barriers in Ohmically heated tokamaks (OHT), ASDEX UG and piecewise analytic DIII-D [Luxon, J.L.; Davis, L.E., Fusion Technol. 8, 441 (1985)] plasma equilibria was predicted by the authors [Ali, H.; Punjabi, A., Plasma Phys. Control. Fusion 49, 1565-1582 (2007)]. Very recently, this prediction for the DIII-D has been corroborated [Volpe, F.A., et al., Nucl. Fusion 52, 054017 (2012)] by field-line tracing calculations, using experimentally constrained Equilibrium Fit (EFIT) [Lao, et al., Nucl. Fusion 25, 1611 (1985)] DIII-D equilibria perturbed to include the vacuum field from the internal coils utilized in the experiments. This second-order approach is applied to the DIII-D tokamak to build noble irrational magnetic barriers inside the chaos created by the locked resonant magnetic perturbations (RMPs) (m, n)=(3, 1)+(4, 1), with m and n the poloidal and toroidal mode numbers of the Fourier expansion of the magnetic perturbation with amplitude δ. A piecewise, analytic, accurate, axisymmetric generating function for the trajectories of magnetic field lines in the DIII-D is constructed in magnetic coordinates from the experimental EFIT Grad-Shafranov solver [Lao, L, et al., Fusion Sci. Technol. 48, 968 (2005)] for the shot 115,467 at 3000 ms in the DIII-D. A symplectic mathematical map is used to integrate field lines in the DIII-D. A numerical algorithm [Ali, H., et al., Radiat. Eff. Def. Solids Inc. Plasma Sc. Plasma Tech. 165, 83 (2010)] based on continued fraction decomposition of the rotational transform labeling the barriers for selecting and identifying the strongest noble irrational barrier is used. The results are compared and contrasted with our previous results on the ASDEX UG. About six times stronger a barrier can be built in the DIII-D than in the ASDEX UG. High magnetic shear near the separatrix in the DIII-D is inferred as the possible cause of this. Implications of this for the DIII-D and the International Thermonuclear Experimental Reactor (ITER) are discussed.

Partitioning and transport of total and methyl mercury in the Lower Fox River, Wisconsin

USGS Publications Warehouse

Hurley, J.P.; Cowell, S.E.; Shafer, M.M.; Hughes, P.E.

1998-01-01

To investigate transport and partitioning processes of Hg(T) in the Fox River, we coupled detailed time series data of total mercury (Hg(T)) at the river mouth with transect sampling in the Lower Fox River. Unfiltered Hg(T) concentrations in the Fox River during the study period (April 1994-October 1995) ranged from 1.8 to 182 ng L(-1) with a median of 24.8 ng L-1, predominantly (93.6%) in the particulate phase. These levels were significantly elevated compared with other large tributaries to Lake Michigan (Hurley, J. P.; Shafer, M. M.; Cowell, S. E.; Overdier, J. T.; Hughes, P. E.; Armstrong, D. E. Environ. Sci. Technol. 1996, 30, 20932098). Transect sampling revealed progressively increasing water column Hg(T) concentrations and Hg(T) particulate enrichment downstream, which were consistent with trends in sediment Hg(T) levels in the river. Resuspended sediments are likely the predominant source of Hg from the Fox River into Green Bay. Despite elevated Hg(T) concentrations, methyl mercury (MeHg) concentrations were relatively low, suggesting limited bioavailability of Hg(T) associated with sediments.To investigate transport and partitioning processes of HgT in the Fox River, we coupled detailed time series data of total mercury (HgT) at the river mouth with transect sampling in the Lower Fox River. Unfiltered HgT concentrations in the Fox River during the study period (April 1994-October 1995) ranged from 1.8 to 182 ng L-1 with a median of 24.8 ng L-1, predominantly (93.6%) in the particulate phase. These levels were significantly elevated compared with other large tributaries to Lake Michigan. Transect sampling revealed progressively increasing water column HgT concentrations and HgT particulate enrichment downstream, which were consistent with trends in sediment HgT levels in the river. Resuspended sediments are likely the predominant source of Hg from the Fox River into Green Bay. Despite elevated HgT concentrations, methyl mercury (MeHg) concentrations were relatively low, suggesting limited bioavailability of HgT associated with sediments.

Linking of EEM spectra with FTICRMS data via van Krevelen diagrams and rank correlation

NASA Astrophysics Data System (ADS)

Herzsprung, Peter; von Tümpling, Wolf; Hertkorn, Norbert; Harir, Mourad; Bravidor, Jenny; Büttner, Olaf; Friese, Kurt; Schmitt-Kopplin, Philippe

2014-05-01

DOM plays an important role in both natural and engineered water systems. Due to its sensitivity and non-destruction of samples EEM is widespread used for comprehension of CDOM. EEM provides sensitive bulk optical parameters with low structural resolution concerning DOM quality even when spectra are modelled by PARAFAC or EEM is coupled to chromatography. Fourier transform ion cyclotron resonance mass spectrometry (FTICRMS) is a high-resolution analytical tool to determine the elemental compositions of thousands of DOM components directly out of mixtures. Lacking the ability for identification of distinct chemical substances (isomers), the elemental compositions can nevertheless be allocated to biogeochemical pools by means of van Krevelen diagrams. The spearman rank correlation was applied to link the EEM intensities (humic like fluorescence) with exact molecular formulas and their corresponding relative mass peak abundances. The initiative for this study to find out what is humic like fluorescence was the environmental problem of increasing levels of organic carbon in fresh waters as a great challenge for processing and commercial supply of drinking water. In the southern Saxony region, Germany, raw drinking water is mainly received from reservoirs situated in the ore mountains (Erzgebirge). Most of these reservoirs are affected by high concentrations of humic substances detected by the drinking water administration via measurement of the dissolved organic carbon (DOC) and the spectral absorption coefficient at 254 nm (SAC254). To get a better insight into the DOM composition, the seasonal variability of DOM quality was determined using EEM and FTICRMS and coupling these two methods in the catchment area of the reservoir Muldenberg. Thereby, humic-like fluorescence could be allocated to the pool of oxygen-rich and relatively unsaturated components with stoichiometries similar to those of tannic acids [1]. [1] Herzsprung, P., von Tümpling, W., Hertkorn, N., Harir, M., Büttner, O., Bravidor, J., Friese, K., Schmitt-Kopplin, P. Variations of DOM quality in inflows of a drinking water reservoir: Linking of van Krevelen diagrams with EEMF spectra by rank correlation. Environ. Sci. Technol. 46, 5511-5518 (2012).

Biogeochemial modeling of biodegradation and stable isotope fractionation of DCE in a small-scale wetland

NASA Astrophysics Data System (ADS)

Alvarez-Zaldívar, Pablo; Imfeld, Gwenaël; Maier, Uli; Centler, Florian; Thullner, Martin

2013-04-01

In recent years, the use of (constructed) wetlands has gained significant attention for the in situ remediation of groundwater contaminated with (chlorinated) organic hydrocarbons. Although many sophisticated experimental methods exist for the assessment of contaminant removal in such wetlands the understanding how changes in wetland hydrochemistry affect the removal processes is still limited. This knowledge gap might be reduced by the use of biogeochemical reactive transport models. This study presents the reactive transport simulation of a small-scale constructed wetland treated with groundwater containing cis-1,2-dichloroethene (cDCE). Simulated processes consider different cDCE biodegradation pathways and the associated carbon isotope fractionation, a set of further (bio)geochemical processes as well as the activity of the plant roots. Spatio-temporal hydrochemical and isotope data from a long-term constructed wetland experiment [1] are used to constrain the model. Simulation results for the initial oxic phase of the wetland experiment indicate carbon isotope enrichment factors typical for cometabolic DCE oxidation, which suggests that aerobic treatment of cDCE is not an optimal remediation strategy. For the later anoxic phase of the experiment model derived enrichment factors indicate reductive dechlorination pathways. This degradation is promoted at all wetland depths by a sufficient availability of electron donor and carbon sources from root exudates, which makes the anoxic treatment of groundwater in such wetlands an effective remediation strategy. In combination with the previous experimental data results from this study suggest that constructed wetlands are viable remediation means for the treatment of cDCE contaminated groundwater. Reactive transport models can improve the understanding of the factors controlling chlorinated ethenes removal, and the used model approach would also allow for an optimization of the wetland operation needed for a complete degradation of these contaminants. [1] Imfeld, G., Aragonés, C., Zeiger, S., von Eckstädt, C., Paschke, H., Trabitzsch, R., Weiss, H., and Richnow, H. (2008). Tracking in situ biodegradation of 1,2-dicholoroethenes in a model wetland. Environ. Sci. Technol., 42: 7924-7930.

Short-interval repeat ground-based surveys of fugitive emissions from oil production facilities in the Bakken

NASA Astrophysics Data System (ADS)

Englander, J. G.; Wang, J.; Lebel, E.; Brandt, A. R.; Jackson, R. B.

2016-12-01

There has been a growing body of research focused on fugitive emissions from oil and gas production. Some studies are bottom-up, component-level studies of individual leaks, while others use atmospheric flux quantification to estimate overall leakage [1]. These studies represent static views of the emissions from a particular region or piece of equipment. There have not (as of yet) been studies examining how the leaks in a facility change over time. Also, challenges have arisen due to study designs that primarily rely on operator cooperation, raising the potential of participation bias in samples taken. This study investigates the persistence of leaking wellpads in the Bakken formation over time, utilizing ground-based observations with an optical gas imaging camera (FLIR GF320). This study examines - without operator foreknowledge - operations which are visible from public roads. This study is broken up into two phases: Phase A included seventy well pads observed over seven separate visits (15, 30, 45, 60, 75, 180, 365 days) where well sites were selected using prior observations to include a higher proportion of leaking wells than across the population overall. Phase B includes sixty-two randomly selected well pads observed over six visits (15, 30, 45, 60, 75, 180 days). This study examines the dynamics between leaking and non-leaking sites over time by comparing the observed presence (or absence) of leaks in a Monte Carlo simulation to a random leak distribution [2]. Even after 180 days, the number of well pads that persisted as either leaking or non-leaking were more than 2σ away from that expected using a random distribution of leaks. This indicates that the mitigation of previously leaking wells could have a significant impact in the reduction of fugitive emissions through enabling persistent improvements in leakage behavior. [1] D. R. Lyon et al. "Aerial surveys of elevated hydrocarbon emissions from oil and gas production sites," Environ. Sci. Technol., p. acs.est.6b00705, Apr. 2016. [2] J. Peischl et al. "Quantifying atmospheric methane emissions from oil and natural gas production in the Bakken shale region of North Dakota," J. Geophys. Res. Atmos., May 2016.

Reductive Dechlorination of Carbon Tetrachloride by Tetrachloroethene and Trichloroethene Respiring Anaerobic Mixed Cultures

NASA Astrophysics Data System (ADS)

Vickstrom, K. E.; Azizian, M.; Semprini, L.

2015-12-01

Carbon tetrachloride (CT) is a toxic and recalcitrant groundwater contaminant with the potential to form a broad range of transformation products. Of the possible biochemical pathways through which CT can be degraded, reductive dehalogenation to less chlorinated compounds and mineralization to carbon dioxide (CO2) appear to be the most frequently utilized pathways by anaerobic organisms. Results will be presented from batch experiments of CT degradation by the Evanite (EV), Victoria Strain (VS) and Point Mugu (PM) anaerobic dechlorinating cultures. The cultures are grown in chemostats and are capable of transforming tetrachloroethene (PCE) or trichloroethene (TCE) to ethene by halorespiration via reductive dehalogenase enzymes. For the batch CT transformation tests, the cells along with supernatant were harvested from chemostats fed PCE or TCE, but never CT. The batch reactors were initially fed 0.0085 mM CT and an excess of formate (EV and VS) or lactate (PM) as electron donor. Transformation of CT was 100% with about 20% converted to chloroform (CF) and undetected products. Multiple additions of CT showed a slowing of pseudo first-order CT transformation rates across all cultures. Batch reactors were then established and fed 0.085 mM CT with an excess of electron donor in order to better quantify the reductive pathway. CT was transformed to CF and dichloromethane (DCM), with trace amounts of chloromethane (CM) detected. Between 60-90% of the mass added to the system was accounted for, showing that the majority of the carbon tetrachloride present is being reductively dehalogenated. Results from batch reactors that were poisoned using sodium azide, and from reactors not provided electron donor will be presented to distinguish between biotic and abiotic reactions. Furthermore, results from reactors prepared with acetylene (a potent, reversible inhibitor of reductive dehalogenases (1)) will be presented as a means of identifying the enzymes involved in the transformation of CT. The results clearly demonstrate that reductive dechlorination of CT can be promoted by anaerobic cultures not previously acclimated to CT. 1. G. Pon, M. R. Hyman, L. Semprini, Environ. Sci. Technol. 37, 3181-3188 (2003).

Using high resolution measurements of gas tracers to determine metabolic rates in streams

NASA Astrophysics Data System (ADS)

Knapp, J. L.; Osenbrück, K.; Brennwald, M. S.; Cirpka, O. A.

2017-12-01

Hyporheic exchange and other hyporheic processes are strongly linked to stream respiration, as the majority of a streams' microorganisms are located within the streambed. Directly estimating these respiration rates on the reach scale is usually not possible, but they can indirectly be inferred from measurements of dissolved oxygen. This, however, requires determining stream reaeration rates with high precision. Conducting gas-tracer tests has been found to be the most reliable method to estimate stream reaeration, but the majority of field-based sampling techniques for tracer gases are either costly in time and materials, or imprecise. By contrast, on-site gas analysis using gas-equilibrium membrane-inlet mass spectrometers (miniRUEDI, Gasometrix GmbH [1]) avoid the errors caused by sampling, storage, and analysis in the standard sampling techniques. Furthermore, the high analytical frequency of the on-site mass-spectrometer provides concentration data exhibiting a low uncertainty. We present results from gas-tracer tests with a continuous injection of propane and noble gases as tracers in a number of small streams. The concentrations of the tracer gases are recorded continuously over time at the first measurement station to account for fluctuations of the input signal, whereas shorter sample sets are collected at all further measurement stations. Reaeration rate constants are calculated from gas measurements for individual stream sections. These rates are then used to estimate metabolic rates of respiration and primary production based on time series of oxygen measurements. To demonstrate the advancement of the method provided by the on-site analysis, results from measurements performed by on-site mass spectroscopy are compared to those from traditional headspace sampling with gas chromatography analysis. Additionally, differences in magnitude and uncertainty of the obtained reaeration rates of oxygen and calculated metabolic rates from both methods highlight the usefulness of the high-frequency on-site analysis. [1] Brennwald, M. S., Schmidt, M., Oser, J., and Kipfer, R. (2016). A portable and autonomous mass spectrometric system for on-site environmental gas analysis. Environ. Sci. Technol., 50(24):13455-13463. Doi: 10.1021/acs.est.6b03669

Continuous monitoring of dissolved gases with membrane inlet mass spectrometry to fingerprint river biochemical activity

NASA Astrophysics Data System (ADS)

Vautier, Camille; Chatton, Eliot; Abbott, Benjamin; Harjung, Astrid; Labasque, Thierry; Guillou, Aurélie; Pannard, Alexandrine; Piscart, Christophe; Laverman, Anniet; Kolbe, Tamara; Massé, Stéphanie; de Dreuzy, Jean-Raynald; Thomas, Zahra; Aquilina, Luc; Pinay, Gilles

2017-04-01

Water quality in rivers results from biogeochemical processes in contributing hydrological compartments (soils, aquifers, hyporheic and riparian zones) and biochemical activity in the river network itself. Consequently, chemical fluxes fluctuate on multiple spatial and temporal scales, leading eventually to complex concentration signals in rivers. We characterized these fluctuations with innovative continuous monitoring of dissolved gases, to quantify transport and reaction processes occurring in different hydrological compartments. We performed stream-scale experiments in two headwater streams in Brittany, France. Factorial injections of inorganic nitrogen (NH4NO3), inorganic phosphate (P2O5) and multiple sources of labile carbon (acetate, tryptophan) were implemented in the two streams. We used a new field application of membrane inlet mass spectrometry to continuously monitor dissolved gases for multiple day-night periods (Chatton et al., 2016). Quantified gases included He, O2, N2, CO2, CH4, N2O, and 15N of dissolved N2 and N2O. We calibrated and assessed the methodology with well-established complementary techniques including gas chromatography and high-frequency water quality sensors. Wet chemistry and radon analysis complemented the study. The analyses provided several methodological and ecological insights and demonstrated that high frequency variations linked to background noise can be efficiently determined and filtered to derive effective fluxes. From a more fundamental point of view, the tested stream segments were fully characterized with extensive sampling of riverbeds and laboratory experiments, allowing scaling of point-level microbial and invertebrate diversity and activity on in-stream processing. This innovative technology allows fully-controlled in-situ experiments providing rich information with a high signal to noise ratio. We present the integrated nutrient demand and uptake and discuss limiting processes and elements at the reach and catchment scales. Eliot Chatton, Thierry Labasque, Jérôme de La Bernardie, Nicolas Guihéneuf, Olivier Bour, Luc Aquilina. 2016. Field Continuous Measurement of Dissolved Gases with a CF-MIMS: Applications to the Physics and Biogeochemistry of Groundwater Flow. Environ. Sci. Technol.

Mobility of engineered inorganic nanoparticles in porous media

NASA Astrophysics Data System (ADS)

Metreveli, George; Heidmann, Ilona; Schaumann, Gabriele Ellen

2013-04-01

Besides the excellent properties and great potential for various industrial, medical, pharmaceutical, cosmetic, and life science applications, engineered inorganic nanoparticles (EINP) can show also disadvantages concerning increasing risk potential with increasing application, if they are released in the environmental systems. EINP can influence microbial activity and can show toxic effects (Fabrega et al., 2009). Similar to the inorganic natural colloids, EINP can be transported in soil and groundwater systems (Metreveli et al., 2005). Furthermore, due to the large surface area and high sorption and complex formation capacity, EINP can facilitate transport of different contaminants. In this study the mobility behaviour of EINP and their effect on the transport of different metal(loid) species in water saturated porous media was investigated. For these experiments laboratory column system was used. The column was filled with quartz sand. The interactions between EINP and metal(loid)s were characterised by coupling of asymmetrical flow field flow fractionation (AF4) with inductively coupled plasma mass spectrometer (ICP-MS). As EINP laponite (synthetic three layer clay mineral), and as metal(loid)s Cu, Pb, Zn, Pt and As were used. In AF4 experiments sorption of metal(loid)s on the surface of EINP could be observed. The extent of interactions was influenced by pH value and was different for different metal(loid)s. Laboratory column experiments showed high mobility of EINP, which facilitated transport of most of metal(loid)s in water saturated porous media. Furthermore the migration of synthetic silver nanoparticles in natural soil columns was determined in leaching experiments. Acknowledgement Financial support by German Research Council (DFG) and Max-Buchner-Research Foundation (MBFSt) is gratefully acknowledged. We thank Karlsruhe Institute of Technology (KIT) for the opportunity to perform the column and AF4 experiments. References: Fabrega, J., Fawcett, S. R., Renshaw, J. C. Lead, J. R. 2009. Silver nanoparticle impact on bacterial growth: Effect of pH, concentration, and organic matter. Environ. Sci. Technol. 43 (19): 7285-7290 Metreveli, G., Kaulisch, E.-M., Frimmel, F. H. 2005. Coupling of a column system with ICP-MS for the characterisation of colloid mediated metal(loid) transport in porous media. Acta Hydrochim. Hydrobiol. 33 (4): 337-345

Predicting Organic Cation Sorption Coefficients: Accounting for Competition from Sorbed Inorganic Cations Using a Simple Probe Molecule.

PubMed

Jolin, William C; Goyetche, Reaha; Carter, Katherine; Medina, John; Vasudevan, Dharni; MacKay, Allison A

2017-06-06

With the increasing number of emerging contaminants that are cationic at environmentally relevant pH values, there is a need for robust predictive models of organic cation sorption coefficients (K d ). Current predictive models fail to account for the differences in the identity, abundance, and affinity of surface-associated inorganic exchange ions naturally present at negatively charged receptor sites on environmental solids. To better understand how organic cation sorption is influenced by surface-associated inorganic exchange ions, sorption coefficients of 10 organic cations (including eight pharmaceuticals and two simple probe organic amines) were determined for six homoionic forms of the aluminosilicate mineral, montmorillonite. Organic cation sorption coefficients exhibited consistent trends for all compounds across the various homoionic clays with sorption coefficients (K d ) decreasing as follows: K d Na + > K d NH 4 + ≥ K d K + > K d Ca 2+ ≥ K d Mg 2+ > K d Al 3+ . This trend for competition between organic cations and exchangeable inorganic cations is consistent with the inorganic cation selectivity sequence, determined for exchange between inorganic ions. Such consistent trends in competition between organic and inorganic cations suggested that a simple probe cation, such as phenyltrimethylammonium or benzylamine, could capture soil-to-soil variations in native inorganic cation identity and abundance for the prediction of organic cation sorption to soils and soil minerals. Indeed, sorption of two pharmaceutical compounds to 30 soils was better described by phenyltrimethylammonium sorption than by measures of benzylamine sorption, effective cation exchange capacity alone, or a model from the literature (Droge, S., and Goss, K. Environ. Sci. Technol. 2013, 47, 14224). A hybrid approach integrating structural scaling factors derived from this literature model of organic cation sorption, along with phenyltrimethylammonium K d values, allowed for estimation of K d values for more structurally complex organic cations to homoionic montmorillonites and to heteroionic soils (mean absolute error of 0.27 log unit). Accordingly, we concluded that the use of phenyltrimethylammonium as a probe compound was a promising means to account for the identity, affinity, and abundance of natural exchange ions in the prediction of organic cation sorption coefficients for environmental solids.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Metzler, Dominik; Oehrlein, Gottlieb S., E-mail: oehrlein@umd.edu; Li, Chen

The need for atomic layer etching (ALE) is steadily increasing as smaller critical dimensions and pitches are required in device patterning. A flux-control based cyclic Ar/C{sub 4}F{sub 8} ALE based on steady-state Ar plasma in conjunction with periodic, precise C{sub 4}F{sub 8} injection and synchronized plasma-based low energy Ar{sup +} ion bombardment has been established for SiO{sub 2} [Metzler et al., J. Vac. Sci. Technol. A 32, 020603 (2014)]. In this work, the cyclic process is further characterized and extended to ALE of silicon under similar process conditions. The use of CHF{sub 3} as a precursor is examined and comparedmore » to C{sub 4}F{sub 8}. CHF{sub 3} is shown to enable selective SiO{sub 2}/Si etching using a fluorocarbon (FC) film build up. Other critical process parameters investigated are the FC film thickness deposited per cycle, the ion energy, and the etch step length. Etching behavior and mechanisms are studied using in situ real time ellipsometry and x-ray photoelectron spectroscopy. Silicon ALE shows less self-limitation than silicon oxide due to higher physical sputtering rates for the maximum ion energies used in this work, ranged from 20 to 30 eV. The surface chemistry is found to contain fluorinated silicon oxide during the etching of silicon. Plasma parameters during ALE are studied using a Langmuir probe and establish the impact of precursor addition on plasma properties.« less

On a novel low cost high accuracy experimental setup for tomographic particle image velocimetry

NASA Astrophysics Data System (ADS)

Discetti, Stefano; Ianiro, Andrea; Astarita, Tommaso; Cardone, Gennaro

2013-07-01

This work deals with the critical aspects related to cost reduction of a Tomo PIV setup and to the bias errors introduced in the velocity measurements by the coherent motion of the ghost particles. The proposed solution consists of using two independent imaging systems composed of three (or more) low speed single frame cameras, which can be up to ten times cheaper than double shutter cameras with the same image quality. Each imaging system is used to reconstruct a particle distribution in the same measurement region, relative to the first and the second exposure, respectively. The reconstructed volumes are then interrogated by cross-correlation in order to obtain the measured velocity field, as in the standard tomographic PIV implementation. Moreover, differently from tomographic PIV, the ghost particle distributions of the two exposures are uncorrelated, since their spatial distribution is camera orientation dependent. For this reason, the proposed solution promises more accurate results, without the bias effect of the coherent ghost particles motion. Guidelines for the implementation and the application of the present method are proposed. The performances are assessed with a parametric study on synthetic experiments. The proposed low cost system produces a much lower modulation with respect to an equivalent three-camera system. Furthermore, the potential accuracy improvement using the Motion Tracking Enhanced MART (Novara et al 2010 Meas. Sci. Technol. 21 035401) is much higher than in the case of the standard implementation of tomographic PIV.

Comparing simulation of plasma turbulence with experiment

NASA Astrophysics Data System (ADS)

Ross, David W.; Bravenec, Ronald V.; Dorland, William; Beer, Michael A.; Hammett, G. W.; McKee, George R.; Fonck, Raymond J.; Murakami, Masanori; Burrell, Keith H.; Jackson, Gary L.; Staebler, Gary M.

2002-01-01

The direct quantitative correspondence between theoretical predictions and the measured plasma fluctuations and transport is tested by performing nonlinear gyro-Landau-fluid simulations with the GRYFFIN (or ITG) code [W. Dorland and G. W. Hammett, Phys. Fluids B 5, 812 (1993); M. A. Beer and G. W. Hammett, Phys. Plasmas 3, 4046 (1996)]. In an L-mode reference discharge in the DIII-D tokamak [J. L. Luxon and L. G. Davis, Fusion Technol. 8, 441 (1985)], which has relatively large fluctuations and transport, the turbulence is dominated by ion temperature gradient (ITG) modes. Trapped electron modes and impurity drift waves also play a role. Density fluctuations are measured by beam emission spectroscopy [R. J. Fonck, P. A. Duperrex, and S. F. Paul, Rev. Sci. Instrum. 61, 3487 (1990)]. Experimental fluxes and corresponding diffusivities are analyzed by the TRANSP code [R. J. Hawryluk, in Physics of Plasmas Close to Thermonuclear Conditions, edited by B. Coppi, G. G. Leotta, D. Pfirsch, R. Pozzoli, and E. Sindoni (Pergamon, Oxford, 1980), Vol. 1, p. 19]. The shape of the simulated wave number spectrum is close to the measured one. The simulated ion thermal transport, corrected for E×B low shear, exceeds the experimental value by a factor of 1.5 to 2.0. The simulation overestimates the density fluctuation level by an even larger factor. On the other hand, the simulation underestimates the electron thermal transport, which may be accounted for by modes that are not accessible to the simulation or to the BES measurement.

EDITORIAL: Award for Patrick Gill

NASA Astrophysics Data System (ADS)

Hauptmann, Peter

2007-12-01

On behalf of the journal I would like to congratulate Professor Patrick Gill, a long-serving member of the Editorial Board for Measurement Science and Technology, who has been awarded the prestigious Institute of Physics Young medal and prize for world-leading contributions to optical frequency metrology. He is recognized as the UK leader in the quest for very accurate optical clocks. Professor Gill's work is concerned with the development of cold trapped ion systems as optical frequency standards with potential for future redefinition of the SI second, and the frequency metrology needed to relate optical and microwave standards to high accuracy. Interested readers may wish to read a short review of the wider state-of-the-art development of single cold trapped ion frequency standards, coupled with a more detailed account of results achieved at the National Physical Laboratory, written by Professor Gill and co-workers from NPL: ''Trapped ion optical frequency standards'' by P Gill, G P Barwood, H A Klein, G Huang, S A Webster, P J Blythe, K Hosaka, S N Lea and H S Margolis 2003 Meas. Sci. Technol. 14 (8) 1174-86 He was one of the very early developers of the frequency comb idea, and in 2004 he led an experiment where the femtosecond laser frequency comb measured the prototype optical clock frequency, based on a strontium-ion optical transition, with accuracy close to the capability of the best caesium microwave clocks. Once again I congratulate Professor Gill and wish him every success for his future work.

Atmospheric H2O2 measurement: comparison of cold trap method with impinger bubbling method

NASA Technical Reports Server (NTRS)

Sakugawa, H.; Kaplan, I. R.

1987-01-01

Collection of atmospheric H2O2 was performed by a cold trap method using dry ice-acetone as the refrigerant. The air was drawn by a pump into a glass gas trap immersed in the dry ice-acetone slush in a dewar flask at a flow rate of 2.5 l min-1 for approximately 2 h. Collection efficiency was > 99% and negligible interferences by O3, SO2 or organic matter with the collected H2O2 in the trap were observed. This method was compared with the air impinger bubbling method which has been previously described (Kok et al., 1978a, b, Envir. Sci. Technol. 12, 1072-1080). The measured total peroxide (H2O2 + organic peroxide) values in a series of aim samples collected by the impinger bubbling method (0.06-3.7 ppb) were always higher than those obtained by the cold trap method (0.02-1.2 ppb). Laboratory experiments suggest that the difference in values between the two methods probably results from the aqueous phase generation of H2O2 and organic peroxide in the impinger solution by a reaction of atmospheric O3 with olefinic and aromatic compounds. If these O3-organic compound reactions which occur in the impinger also occur in aqueous droplets in the atmosphere, the process could be very important for aqueous phase generation of H2O2 in clouds and rainwater.

Study of dual radio frequency capacitively coupled plasma: an analytical treatment matched to an experiment

NASA Astrophysics Data System (ADS)

Saikia, P.; Bhuyan, H.; Escalona, M.; Favre, M.; Wyndham, E.; Maze, J.; Schulze, J.

2018-01-01

The behavior of a dual frequency capacitively coupled plasma (2f CCP) driven by 2.26 and 13.56 MHz radio frequency (rf) source is investigated using an approach that integrates a theoretical model and experimental data. The basis of the theoretical analysis is a time dependent dual frequency analytical sheath model that casts the relation between the instantaneous sheath potential and plasma parameters. The parameters used in the model are obtained by operating the 2f CCP experiment (2.26 MHz + 13.56 MHz) in argon at a working pressure of 50 mTorr. Experimentally measured plasma parameters such as the electron density, electron temperature, as well as the rf current density ratios are the inputs of the theoretical model. Subsequently, a convenient analytical solution for the output sheath potential and sheath thickness was derived. A comparison of the present numerical results is done with the results obtained in another 2f CCP experiment conducted by Semmler et al (2007 Plasma Sources Sci. Technol. 16 839). A good quantitative correspondence is obtained. The numerical solution shows the variation of sheath potential with the low and high frequency (HF) rf powers. In the low pressure plasma, the sheath potential is a qualitative measure of DC self-bias which in turn determines the ion energy. Thus, using this analytical model, the measured values of the DC self-bias as a function of low and HF rf powers are explained in detail.

Comparison of surface vacuum ultraviolet emissions with resonance level number densities. II. Rare-gas plasmas and Ar-molecular gas mixtures

DOE Office of Scientific and Technical Information (OSTI.GOV)

Boffard, John B., E-mail: jboffard@wisc.edu; Lin, Chun C.; Wang, Shicong

2015-03-15

Vacuum ultraviolet (VUV) emissions from excited plasma species can play a variety of roles in processing plasmas, including damaging the surface properties of materials used in semiconductor processing. Depending on their wavelength, VUV photons can easily transmit thin upper dielectric layers and affect the electrical characteristics of the devices. Despite their importance, measuring VUV fluxes is complicated by the fact that few materials transmit at VUV wavelengths, and both detectors and windows are easily damaged by plasma exposure. The authors have previously reported on measuring VUV fluxes in pure argon plasmas by monitoring the concentrations of Ar(3p{sup 5}4s) resonance atomsmore » that produce the VUV emissions using noninvasive optical emission spectroscopy in the visible/near-infrared wavelength range [Boffard et al., J. Vac. Sci. Technol., A 32, 021304 (2014)]. Here, the authors extend this technique to other rare-gases (Ne, Kr, and Xe) and argon-molecular gas plasmas (Ar/H{sub 2}, Ar/O{sub 2}, and Ar/N{sub 2}). Results of a model for VUV emissions that couples radiation trapping and the measured rare-gas resonance level densities are compared to measurements made with both a calibrated VUV photodiode and a sodium salicylate fluorescence detection scheme. In these more complicated gas mixtures, VUV emissions from a variety of sources beyond the principal resonance levels of the rare gases are found to contribute to the total VUV flux.« less

Simulations of stress evolution and the current density scaling of electromigration-induced failure times in pure and alloyed interconnects

NASA Astrophysics Data System (ADS)

Park, Young-Joon; Andleigh, Vaibhav K.; Thompson, Carl V.

1999-04-01

An electromigration model is developed to simulate the reliability of Al and Al-Cu interconnects. A polynomial expression for the free energy of solution by Murray [Int. Met. Rev. 30, 211 (1985)] was used to calculate the chemical potential for Al and Cu while the diffusivities were defined based on a Cu-trapping model by Rosenberg [J. Vac. Sci. Technol. 9, 263 (1972)]. The effects of Cu on stress evolution and lifetime were investigated in all-bamboo and near-bamboo stud-to-stud structures. In addition, the significance of the effect of mechanical stress on the diffusivity of both Al and Cu was determined in all-bamboo and near-bamboo lines. The void nucleation and growth process was simulated in 200 μm, stud-to-stud lines. Current density scaling behavior for void-nucleation-limited failure and void-growth-limited failure modes was simulated in long, stud-to-stud lines. Current density exponents of both n=2 for void nucleation and n=1 for void growth failure modes were found in both pure Al and Al-Cu lines. Limitations of the most widely used current density scaling law (Black's equation) in the analysis of the reliability of stud-to-stud lines are discussed. By modifying the input materials properties used in this model (when they are known), this model can be adapted to predict the reliability of other interconnect materials such as pure Cu and Cu alloys.

Image simulation and surface reconstruction of undercut features in atomic force microscopy

NASA Astrophysics Data System (ADS)

Qian, Xiaoping; Villarrubia, John; Tian, Fenglei; Dixson, Ronald

2007-03-01

CD-AFMs (critical dimension atomic force microscopes) are instruments with servo-control of the tip in more than one direction. With appropriately "boot-shaped" or flared tips, such instruments can image vertical or even undercut features. As with any AFM, the image is a dilation of the sample shape with the tip shape. Accurate extraction of the CD requires a correction for the tip effect. Analytical methods to correct images for the tip shape have been available for some time for the traditional (vertical feedback only) AFMs, but were until recently unavailable for instruments with multi-dimensional feedback. Dahlen et al. [J. Vac. Sci. Technol. B23, pp. 2297-2303, (2005)] recently introduced a swept-volume approach, implemented for 2-dimensional (2D) feedback. It permits image simulation and sample reconstruction, techniques previously developed for the traditional instruments, to be extended for the newer tools. We have introduced [X. Qian and J. S. Villarrubia, Ultramicroscopy, in press] an alternative dexel-based method, that does the same in either 2D or 3D. This paper describes the application of this method to sample shapes of interest in semiconductor manufacturing. When the tip shape is known (e.g., by prior measurement using a tip characterizer) a 3D sample surface may be reconstructed from its 3D image. Basing the CD measurement upon such a reconstruction is shown here to remove some measurement artifacts that are not removed (or are incompletely removed) by the existing measurement procedures.

Shrinkage strain-rates of dental resin-monomer and composite systems.

PubMed

Atai, Mohammad; Watts, David C; Atai, Zahra

2005-08-01

The purpose of this study was to investigate the shrinkage strain rate of different monomers, which are commonly used in dental composites and the effect of monomer functionality and molecular mass on the rate. Bis-GMA, TEGDMA, UDMA, MMA, HEMA, HPMA and different ratios of Bis-GMA/TEGDMA were mixed with Camphorquinone and Dimethyl aminoethyle methacrylate as initiator system. The shrinkage strain of the samples photopolymerised at Ca. 550 mW/cm2 and 23 degrees C was measured using the bonded-disk technique of Watts and Cash (Meas. Sci. Technol. 2 (1991) 788-794), and initial shrinkage-strain rates were obtained by numerical differentiation. Shrinkage-strain rates rose rapidly to a maximum, and then fell rapidly upon vitrification. Strain and initial strain rate were dependent upon monomer functionality, molecular mass and viscosity. Strain rates were correlated with Bis-GMA in Bis-GMA/TEGDMA mixtures up to 75-80 w/w%, due to the higher molecular mass of Bis-GMA affecting termination reactions, and then decreased due to its higher viscosity affecting propagation reactions. Monofunctional monomers exhibited lower rates. UDMA, a difunctional monomer of medium viscosity, showed the highest shrinkage strain rate (P < 0.05). Shrinkage strain rate, related to polymerization rate, is an important factor affecting the biomechanics and marginal integrity of composites cured in dental cavities. This study shows how this is related to monomer molecular structure and viscosity. The results are significant for the production, optimization and clinical application of dental composite restoratives.

Characterisation of the incident beam and current diffraction capabilities on the VESUVIO spectrometer

NASA Astrophysics Data System (ADS)

Romanelli, G.; Krzystyniak, M.; Senesi, R.; Raspino, D.; Boxall, J.; Pooley, D.; Moorby, S.; Schooneveld, E.; Rhodes, N. J.; Andreani, C.; Fernandez-Alonso, F.

2017-09-01

The VESUVIO spectrometer at the ISIS pulsed neutron and muon source is a unique instrument amongst those available at neutron facilities. This is the only inverted-geometry neutron spectrometer accessing values of energy and wavevector transfer above tens of eV and {\\mathringA}-1 , respectively, and where deep inelastic neutron scattering experiments are routinely performed. As such, the procedure at the base of the technique has been previously described in an article published by this journal (Mayers and Reiter 2012 Meas. Sci. Technol. 23 045902). The instrument has recently witnessed an upsurge of interest due to a new trend to accommodate, within a single experiment, neutron diffraction and transmission measurements in addition to deep inelastic neutron scattering. This work presents a broader description of the instrument following these recent developments. In particular, we assess the absolute intensity and two-dimensional profile of the incident neutron beam and the capabilities of the backscattering diffraction banks. All results are discussed in the light of recent changes to the moderator viewed by the instrument. We find that VESUVIO has to be considered a high-resolution diffractometer as much as other diffractometers at ISIS, with a resolution as high as 2× 10-3 in backscattering. Also, we describe the extension of the wavelength range of the instrument to include lower neutron energies for diffraction measurements, an upgrade that could be readily applied to other neutron instruments as well.

Femtosecond pulsed laser deposition of amorphous, ultrahard boride thin films

NASA Astrophysics Data System (ADS)

Stock, Michael; Molian, Pal

2004-05-01

Amorphous thin films (300-500 nm) of ultrahard AlMgB10 with oxygen and carbon impurities were grown on Si (100) substrates at 300 K using a solid target of AlMgB14 containing a spinel phase (MgAl2O4) and using a 120 fs pulsed, 800 nm wavelength Ti:sapphire laser. The films were subsequently annealed in argon gas up to 1373 K for 2 h. Scanning electron microscopy (SEM) was used to examine the particulate formation, atomic force microscopy was employed to characterize the film surface topography, x-ray diffraction and transmission electron microscopy were used to determine the microstructure, x-ray photoelectron spectroscopy was performed to examine the film composition, and nanoindentation was employed to study the hardness of thin films. The as-deposited and postannealed films (up to 1273 K) had a stochiometry of AlMgB10 with a significant amount of oxygen and carbon impurities and exhibited amorphous structures for a maximum hardness of 40+/-3 GPa. However, postannealing at higher temperatures led to crystallization and transformation of the film to SiB6 with a substantial loss in hardness. Results are also compared with our previous study on 23 ns, 248 nm wavelength (KrF excimer) pulsed laser deposition of AlMgB14 reported in this journal [Y. Tian, A. Constant, C. C. H. Lo, J. W. Anderegg, A. M. Russell, J. E. Snyder, and P. A. Molian, J. Vac. Sci. Technol. A 21, 1055 (2003)]. .

Skeletal muscle mitochondrial health and spinal cord injury.

PubMed

O'Brien, Laura C; Gorgey, Ashraf S

2016-10-18

Mitochondria are the main source of cellular energy production and are dynamic organelles that undergo biogenesis, remodeling, and degradation. Mitochondrial dysfunction is observed in a number of disease states including acute and chronic central or peripheral nervous system injury by traumatic brain injury, spinal cord injury (SCI), and neurodegenerative disease as well as in metabolic disturbances such as insulin resistance, type II diabetes and obesity. Mitochondrial dysfunction is most commonly observed in high energy requiring tissues like the brain and skeletal muscle. In persons with chronic SCI, changes to skeletal muscle may include remarkable atrophy and conversion of muscle fiber type from oxidative to fast glycolytic, combined with increased infiltration of intramuscular adipose tissue. These changes contribute to a proinflammatory environment, glucose intolerance and insulin resistance. The loss of metabolically active muscle combined with inactivity predisposes individuals with SCI to type II diabetes and obesity. The contribution of skeletal muscle mitochondrial density and electron transport chain activity to the development of the aforementioned comorbidities following SCI is unclear. A better understanding of the mechanisms involved in skeletal muscle mitochondrial dynamics is imperative to designing and testing effective treatments for this growing population. The current editorial will review ways to study mitochondrial function and the importance of improving skeletal muscle mitochondrial health in clinical populations with a special focus on chronic SCI.

Effect of a Cooling Vest on Core Temperature in Athletes With and Without Spinal Cord Injury

PubMed Central

Trbovich, Michelle

2014-01-01

Background: It is well accepted that persons with spinal cord injury (SCI) have impaired ability to regulate core temperature due to impaired vasomotor and sudomotor activity below their level of injury. Impaired heat dissipation puts SCI athletes at great risk of exercise-induced hyperthermia (EIH) (>37.8°C). There is minimal evidence for efficacy of any specific cooling method in SCI athletes in a thermoneutral sport-specific setting. Objective: To evaluate the extent of EIH in persons with and without SCI and subsequently examine the effect of a cooling vest to attenuate rise in core body temperature (Tc). Methods: SCI (n = 17) and able-bodied (AB; n = 19) athletes participated in a 60-minute intermittent sprinting exercise in a thermoneutral (21.1°C-23.9°C) environment. Participants were separated according to their level of injury: tetraplegia defined as above T1 (TP; n = 6), high paraplegia defined as T5 through T1 (HP; n = 5), low paraplegia defined as T6 and below (LP; n = 6), and AB (n = 19). Tc was recorded at 15-minute intervals using an ingestible thermometer pill. This protocol was completed with a cooling vest (V) and without a cooling vest (NV). Results: All SCI and most AB athletes experienced EIH. After 60 minutes, Tc of TP athletes was significantly increased compared to HP (P = .03) and AB athletes (P = .007). There was no significant effect of the vest on Tc over time for any group. Conclusions: TP athletes have the highest risk of exercise-induced hyperthermia. The cooling vest does not significantly attenuate rise in Tc in SCI or AB athletes. PMID:24574824

Effect of a cooling vest on core temperature in athletes with and without spinal cord injury.

PubMed

Trbovich, Michelle; Ortega, Catherine; Schroeder, James; Fredrickson, Mark

2014-01-01

It is well accepted that persons with spinal cord injury (SCI) have impaired ability to regulate core temperature due to impaired vasomotor and sudomotor activity below their level of injury. Impaired heat dissipation puts SCI athletes at great risk of exercise-induced hyperthermia (EIH) (>37.8°C). There is minimal evidence for efficacy of any specific cooling method in SCI athletes in a thermoneutral sport-specific setting. To evaluate the extent of EIH in persons with and without SCI and subsequently examine the effect of a cooling vest to attenuate rise in core body temperature (Tc). SCI (n = 17) and able-bodied (AB; n = 19) athletes participated in a 60-minute intermittent sprinting exercise in a thermoneutral (21.1°C-23.9°C) environment. Participants were separated according to their level of injury: tetraplegia defined as above T1 (TP; n = 6), high paraplegia defined as T5 through T1 (HP; n = 5), low paraplegia defined as T6 and below (LP; n = 6), and AB (n = 19). Tc was recorded at 15-minute intervals using an ingestible thermometer pill. This protocol was completed with a cooling vest (V) and without a cooling vest (NV). All SCI and most AB athletes experienced EIH. After 60 minutes, Tc of TP athletes was significantly increased compared to HP (P = .03) and AB athletes (P = .007). There was no significant effect of the vest on Tc over time for any group. TP athletes have the highest risk of exercise-induced hyperthermia. The cooling vest does not significantly attenuate rise in Tc in SCI or AB athletes.

Perceived influence of intrinsic/extrinsic factors on participation in life activities after spinal cord injury.

PubMed

Cobb, John E; Leblond, Jean; Dumont, Frédéric S; Noreau, Luc

2018-04-03

Various types of limitations on community participation are experienced by people with spinal cord injury (SCI). To determine: 1) the perceived influence of six intrinsic/extrinsic factors (i.e. physical impairment, emotional condition, thinking skills, environment, lack of assistance, discrimination) on participation in 26 life activities, 2) if this influence varied based on extent of participation, and 3) if personal or environmental characteristics influenced perceptions. Secondary analysis of a cohort (SCI Community Survey, n = 1508) using the SCI Person-Perceived Participation in Daily Activities Questionnaire. Frequency tables, Fisher's exact tests and correspondence analyses. Respectively, 79.6% and 38.5% of respondents perceived that their physical impairment and the natural and/or built environment were the main factors that limited participation across all activities. Considering participation between three groups (no participation; less than wanted; as much as wanted), significant differences (p < 0.001) of perceptions were observed in 65% of the combinations (26 activities x 6 factors). The hypothesis that respondents who did not participate would perceive the highest proportion of limitations was confirmed in 41% of the combinations. Perceived influence of the intrinsic/extrinsic factors on participation was not significantly influenced by other personal or environmental characteristics. A majority of people with SCI perceived that their participation is limited by one or more of intrinsic/extrinsic factors. Perceptions regarding which factors influence participation differ between activities and these perceptions appear related to the extent of participation suggesting that those who actively participate could be the most sensitive to limitations in certain activities. Copyright © 2018 Elsevier Inc. All rights reserved.

Control of locomotor stability in stabilizing and destabilizing environments.

PubMed

Wu, Mengnan/Mary; Brown, Geoffrey; Gordon, Keith E

2017-06-01

To develop effective interventions targeting locomotor stability, it is crucial to understand how people control and modify gait in response to changes in stabilization requirements. Our purpose was to examine how individuals with and without incomplete spinal cord injury (iSCI) control lateral stability in haptic walking environments that increase or decrease stabilization demands. We hypothesized that people would adapt to walking in a predictable, stabilizing viscous force field and unpredictable destabilizing force field by increasing and decreasing feedforward control of lateral stability, respectively. Adaptations in feedforward control were measured using after-effects when fields were removed. Both groups significantly (p<0.05) decreased step width in the stabilizing field. When the stabilizing field was removed, narrower steps persisted in both groups and subjects with iSCI significantly increased movement variability (p<0.05). The after-effect of walking in the stabilizing field was a suppression of ongoing general stabilization mechanisms. In the destabilizing field, subjects with iSCI took faster steps and increased lateral margins of stability (p<0.05). Step frequency increases persisted when the destabilizing field was removed (p<0.05), suggesting that subjects with iSCI made feedforward adaptions to increase control of lateral stability. In contrast, in the destabilizing field, non-impaired subjects increased movement variability (p<0.05) and did not change step width, step frequency, or lateral margin of stability (p>0.05). When the destabilizing field was removed, increases in movement variability persisted (p<0.05), suggesting that non-impaired subjects made feedforward decreases in resistance to perturbations. Published by Elsevier B.V.

Study of Np(V) Sorption by Ionic Exchange on Na, K, Ca and Mg-Montmorillonite

NASA Astrophysics Data System (ADS)

Benedicto, A.; Begg, J.; Zhao, P.; Kersting, A. B.; Zavarin, M.

2012-12-01

The transport behavior of actinides in soil and ground water are highly influenced by clay minerals due to their ubiquity in the environment, reactivity and colloidal properties. Neptunium(V) has been introduced in the environment as a result of nuclear weapons testing [e.g. 1, 2] and is a radionuclide of potential interest for safety assessment of high level radioactive waste disposal because its long half-life and high toxicity [3]. Surface complexation and ionic exchange have been identified as Np(V) sorption mechanisms onto montmorillonite. At pH below 5, Np(V) sorption is mainly attributed to ionic exchange. This study examines Np(V) ion exchange on Na, K, Ca and Mg forms of montmorillonite. Experiments were carried out using 237Np concentrations between 2 x 10-8 M and 5 x 10-6 M at three different ionic strengths 0.1, 0.01 and 0.001M. The pH was maintained at 4.5. Np(V) sorption to montmorillonite homoionized with monovalent cations (Na and K) demonstrated a markedly different behavior to that observed for montmorillonite homoionized with divalent cations (Ca and Mg). Np sorption to Na and K-montmorillonite was greater than Np sorption to Ca and Mg-montmorillonite. Isotherms with Na and K-montmorillonite showed a strong dependence on ionic strength: the percentage of Np adsorbed was near zero at 0.1M ionic strength, but increased to 30% at 0.001 M ionic strength. This suggests ionic exchange is the main Np adsorption mechanism under the experimental conditions investigated. Dependence on ionic strength was not observed in the Np sorption isotherms for Ca and Mg-montmorillonite indicating a low exchange capacity between Np and divalent cations. Modeling of the sorption experimental data will allow determination of the Na+↔NpO2+ and K+↔NpO2+ ionic exchange constants on montmorillonite. References: [1] A. R. Felmy; K. J. Cantrell; S. D. Conradson, Phys. Chem. Earth 2010, 35, 292-297 [2] D. K. Smith; D. L. Finnegan; S. M. Bowen, J. Environ. Radioact. 2003, 67, (1), 35-51 [3] N. Kozai; T. Ohnuki; S. Muraoka, J. Nucl. Sci. Technol. 1993, 30, (11), 1153-1159 This work was funded by U. S. DOE Office of Biological & Environmental Sciences, Subsurface Biogeochemistry Research Program, and performed under the auspices of the U. S. Department of Energy by Lawrence Livermore National Security, LLC under Contract DE-AC52-07NA27344. A. Benedicto was supported by a Spanish Ministry of Science and Innovation 'FPI' pre-doctoral contract in CIEMAT (Spain). LLNL-ABS-570160

Salt lakes of Western Australia - Natural abiotic formation of volatile organic compounds

NASA Astrophysics Data System (ADS)

Krause, T.; Studenroth, S.; Mulder, I.; Tubbesing, C.; Kotte, K.; Ofner, J.; Junkermann, W.; Schöler, H. F.

2012-04-01

Western Australia is a semi-/arid region that is heavily influenced by global climate change and agricultural land use. The area is known for its many ephemeral saline and hypersaline lakes with a wide range of hydrogeochemical parameters that have gradually changed over the last fifty years. Historically, the region was covered by eucalyptus trees and shrubs, but was cleared mainly within 10 years after WWII to make room for wheat and live stock. After the clearance of the deep rooted native plants the groundwater started to rise, bringing increased amounts of dissolved salts and minerals to the surface and discharging them into streams and lakes. Thus most of Western Australia is influenced by secondary salinisation (soil salting) [1]. Another problem is that the discharged minerals affect the pH of ground and surface water, which ranges from acidic to slightly basic. During the 2011 campaign surface water was measured with a pH between 2.5 and 7.1. Another phenomenon in Western Australia is the decrease of rainfall over the last decades assumed to be linked to the secondary salinisation. The rising saline and mineral rich groundwater increases the biotical and abiotical activity of the salt lakes. Halogenated and non-halogenated volatile organic compounds emitted from those lakes undergo fast oxidation and chemical reactions to form small particles modifying cloud microphysics and thus suppressing rain events [2]. Our objective is to gain a better understanding of this extreme environment with its hypersaline acidic lakes with regard to the potential abiotic formation of volatile organic compounds and its impact on the local climate. In spring 2011 fifty-three sediment samples from ten salt lakes in the Lake King region where taken, freeze-dried and ground. In order to simulate the abiotic formation of volatile organic compounds the soil samples were resuspended with water in gas-tight headspace vials. The headspace was measured using a purge and trap GC/MS. Especially the acidic lakes are sources for trihalomethanes in agreement with laboratory studies on model compounds like catechol [3]. Other compounds that are formed are chloromethane, -butane, -hexane and heptane as well as monocyclic terpenes and furan derivatives. Additionally, there are different sulphur compounds such as thiophene derivatives, carbon disulfide and dimethyl sulfide. Western Australia offers a variety of hypersaline environments with various hydrogeochemical parameters that will help to understand the abiotic formation of different volatile organic compounds. The field of research includes the complex relationships between agriculture, secondary salinisation and particle formation from volatile organic compounds emitted from the salt lakes. [1] Williams, 2001, Hydrobiologia, 466, 329-337. [2] Junkermann et al., 2009, Atmos. Chem. Phys., 9, 6531-6539. [3] Huber et al., 2009, Environ. Sci. Technol., 43 (13), 4934-4939.

The Lunar dusty plasmas -levitation and transport.

NASA Astrophysics Data System (ADS)

Atamaniuk, Barbara; Rothkaehl, Hanna

Lunar dust can exhibit unusual behavior -due to electron photoemission via solar-UV radiation the lunar surface represents a complex plasma -"dusty plasma". The dust grains and lunar surface are electrostatically charged by the Moon's interaction with the local plasma environ-ment and the photoemission of electrons due to solar UV and X-rays. This effect causes the like-charged surface and dust particles to repel each other, and creates a near-surface electric field. Lunar dust must be treated as a dusty plasma. Using analytic (kinetic (Vlasov) and magnetohydrodynamic theory ) and numerical modeling we show physical processes related to levitation and transport dusty plasma on the Moon. These dust grains could affect the lunar environment for radio wave and plasma diagnostics and interfere with exploration activities. References: 1. Wilson T.L. (1992), in Analysis of Interplanetary Dust, M. Zolensky et al. AIP Conf.Proc. 310, 33-44 (AIP, NY), 2.Wilson T.L."LUNAR DUST AND DUSTY PLASMA PHYSICS".40th Lunar and Planetary Science Conference (2009), 3. Grün E., et al.(1993),Nature 363, 144. 4. Morfill G. and Grün E.(1979), Planet. Space Sci.. 27, 1269, 1283, 5. Manka R. and Michel F. (1971), Proc. 2nd Lun. Sci. Conf. 2, 1717 (MIT Press, Cambridge). 6. Manka R. et al.(1973), Lun. Sci.-III, 504. 7. Barbara Atamaniuk "Kinetic Description of Localized Plasma Structure in Dusty Plasmas". Czechoslovak Journal of Physics Vol.54 C 2004

An in-depth understanding of the impact of the environment on participation among people with spinal cord injury.

PubMed

Chang, Feng-Hang; Liu, Cheng-Han; Hung, Hsin-Ping

2017-05-22

To identify environmental factors associated with participation and gain an in-depth understanding of relationships between environmental factors and participation among people with spinal cord injury. Six focus groups (n= 30) with individuals with spinal cord injury were conducted. Two independent coders thematically analyzed the transcribed data. Twenty environmental factors were identified, all of which were classified into eight categories: built environment; natural environment; assistive technology; transportation; information and technology access; economics; social support and social attitudes; and systems, services and policies. While all factors had direct impacts on individuals' participation outcomes, factors within the categories of societal attitudes, policies and economics also affected participation through affecting other environmental factors. Some factors together also showed cumulative or countering effects on participation. Accordingly, a conceptual model of the relationships between environmental factors and participation was constructed. This study highlighted key environmental factors and their impacts on participation of people with spinal cord injury. The findings support previous research findings but also suggest that different factors may have different levels of impact on participation. Based on our findings, rehabilitation practitioners and policymakers can prioritize intervention plans to optimize the environment for people with spinal cord injury and improve their societal participation. Implications for rehabilitation Environmental factors are critical contributors to participation among people with spinal cord injury (SCI) and need to be addressed in rehabilitation programs. Factors with broader impacts on participation, such as societal attitudes and policies, should be treated as priorities in intervention plans aimed at improving participation among people with SCI. Rehabilitation practitioners should not only consider how the community supports people with SCI but also consider how rehabilitation programs change the community.

A Comprehensive Evaluation of H2SO4 formation from OH and sCI pathways in high BVOC environments

NASA Astrophysics Data System (ADS)

Kim, S.; Seco, R.; Park, J. H.; Guenther, A. B.; Smith, J. N.; Kuang, C.; Bustillos, J. O. V.; Tota, J.; Souza, R. A. F. D.

2014-12-01

The recently highlighted importance of stabilized Criegee intermediates (sCI) as an oxidant for atmospheric SO2 triggered a number of studies to assess the atmospheric implications of H2SO4 formation from the sCI reaction pathway. In addition, it has not been clear why new particle formation events are not observed in the Amazon rain forest. The mostly widely speculated reason has been a very low H2SO4 level. We will present quantitative assessments of SO2 oxidation by sCI leading to the H2SO4 production using a comprehensive observational dataset from a tropical rainforest study during the GOAmazon field campaign at the T3 site in Manacapuru, Amazonas, Brazil. To our best knowledge, this is the first observation of H2SO4 and OH in Amazon and is unique for all tropical sites due to the accompanying comprehensive gas and aerosol observations such as CO, NOX, SO2, VOCs, and physical and chemical characteristics of aerosols. We will discuss observed H2SO4 levels during the GOAmazon field campaigns to demonstrate 1) H2SO4 formation potential from OH and sCI oxidation pathways by contrasting extremely clean and relatively polluted air masses and 2) the Implications of the observed H2SO4 levels in new particle formation and particle growth events.

Microlithography and resist technology information at your fingertips via SciFinder

NASA Astrophysics Data System (ADS)

Konuk, Rengin; Macko, John R.; Staggenborg, Lisa

1997-07-01

Finding and retrieving the information you need about microlithography and resist technology in a timely fashion can make or break your competitive edge in today's business environment. Chemical Abstracts Service (CAS) provides the most complete and comprehensive database of the chemical literature in the CAplus, REGISTRY, and CASREACT files including 13 million document references, 15 million substance records and over 1.2 million reactions. This includes comprehensive coverage of positive and negative resist formulations and processing, photoacid generation, silylation, single and multilayer resist systems, photomasks, dry and wet etching, photolithography, electron-beam, ion-beam and x-ray lithography technologies and process control, optical tools, exposure systems, radiation sources and steppers. Journal articles, conference proceedings and patents related to microlithography and resist technology are analyzed and indexed by scientific information analysts with strong technical background in these areas. The full CAS database, which is updated weekly with new information, is now available at your desktop, via a convenient, user-friendly tool called 'SciFinder.' Author, subject and chemical substance searching is simplified by SciFinder's smart search features. Chemical substances can be searched by chemical structure, chemical name, CAS registry number or molecular formula. Drawing chemical structures in SciFinder is easy and does not require compliance with CA conventions. Built-in intelligence of SciFinder enables users to retrieve substances with multiple components, tautomeric forms and salts.

Chromium Isotopes in Marine Carbonates - an Indicator for Climatic Change?

NASA Astrophysics Data System (ADS)

Frei, R.; Gaucher, C.

2010-12-01

Chromium (Cr) stable isotopes experience an increased interest as a tracer of Cr (VI) reduction in groundwater and thus showed their potential as a monitor of remediation of anthropogenic and natural contamination in water (Berna et al., 2009; Izbicki et al., 2008). Chromium stable isotopes in Fe-rich chemical sediments (BIFs and Fe-cherts) have recently also been used as a tracer for Earth's atmospheric oxygenation through time (Frei et al., 2009). We have applied the Cr isotope system to organic-rich carbonates from a late Ediacaran succession in Uruguay (Polanco Formation), from which we have previously analyzed BIFs with extremely fractionated (δ53Cr up to 5.0 ‰) Cr isotope signatures that are part of an underlying deep water clastic sediment (shale-dominated) sequence (Yerbal Formation) deposited in a glacio-marine environment (Gaucher et al.,2004). δ53Cr values of organic rich carbonates correlate with positive and negative carbon isotope excursions (δ13C PDB between -3 and +3 ‰) and with systematic changes in strontium isotope compositions, commonly interpreted as to reflect fluctuations in organic (photosynthetic algae) production related to fluctuations in atmospheric oxygen and weathering intensities, respectively. Slightly positively fractioned δ53Cr values (up to +0.25‰), paralleling positive (δ13C PDB and 87Sr/86Sr ratio excursions would thereby trace elevated atmospheric oxygen levels/pulses possibly related to glacier retreat/melting stages that caused bioproductivity to increase. While the causal link between these multiple isotopic tracers and the mechanisms of Cr stripping into carbonates has to be further investigated in detail, the first indications from this study point to a potentially promising use of stable Cr isotopes in organic-rich carbonates to monitor fluctuations of atmospheric oxygen, particularly over the Neoproterozoic and Phanerozoic ice age periods. E.C. Berna et al. (2010) Cr stable isotopes as indicators of Cr(VI) reduction in groundwater: a detailed time-series study of a point-source plume. Environ. Sci. Technol., v. 44, p. 1043-1048. J.A. Izbicki et al. (2008) Chromium, chromium isotopes and selected trace elements, western Mojave Desert, USA. Applied Geochemistry, v.23, p. 1325-1352. R. Frei et al. (2009) Fluctuations in Precambrian atmospheric oxygenation recorded by chromium isotopes. Nature, v. 461, p. 250-253. C. Gaucher et al. (2004) Chemostratigraphy of the Lower Arroyo del Soldado Group (Vendian, Uruguay) and palaeoclimatic implications. Gondwana Research, v.7, p. 715-730

Manual Wheelchair Skills Training for Community-Dwelling Veterans with Spinal Cord Injury: A Randomized Controlled Trial.

PubMed

Kirby, R Lee; Mitchell, Doug; Sabharwal, Sunil; McCranie, Mark; Nelson, Audrey L

2016-01-01

To test the hypotheses that community-dwelling veterans with spinal cord injury (SCI) who receive the Wheelchair Skills Training Program (WSTP) in their own environments significantly improve their manual wheelchair-skills capacity, retain those improvements at one year and improve participation in comparison with an Educational Control (EC) group. We carried out a randomized controlled trial, studying 106 veterans with SCI from three Veterans Affairs rehabilitation centers. Each participant received either five one-on-one WSTP or EC sessions 30-45 minutes in duration. The main outcome measures were the total and subtotal percentage capacity scores from the Wheelchair Skills Test 4.1 (WST) and Craig Handicap Assessment and Reporting Technique (CHART) scores. Participants in the WSTP group improved their total and Advanced-level WST scores by 7.1% and 30.1% relative to baseline (p < 0.001) and retained their scores at one year follow-up. The success rates for individual skills were consistent with the total and subtotal WST scores. The CHART Mobility sub-score improved by 3.2% over baseline (p = 0.021). Individualized wheelchair skills training in the home environment substantially improves the advanced and total wheelchair skills capacity of experienced community-dwelling veterans with SCI but has only a small impact on participation.

Manual Wheelchair Skills Training for Community-Dwelling Veterans with Spinal Cord Injury: A Randomized Controlled Trial

PubMed Central

Mitchell, Doug; Sabharwal, Sunil; McCranie, Mark; Nelson, Audrey L.

2016-01-01

Objectives To test the hypotheses that community-dwelling veterans with spinal cord injury (SCI) who receive the Wheelchair Skills Training Program (WSTP) in their own environments significantly improve their manual wheelchair-skills capacity, retain those improvements at one year and improve participation in comparison with an Educational Control (EC) group. Methods We carried out a randomized controlled trial, studying 106 veterans with SCI from three Veterans Affairs rehabilitation centers. Each participant received either five one-on-one WSTP or EC sessions 30–45 minutes in duration. The main outcome measures were the total and subtotal percentage capacity scores from the Wheelchair Skills Test 4.1 (WST) and Craig Handicap Assessment and Reporting Technique (CHART) scores. Results Participants in the WSTP group improved their total and Advanced-level WST scores by 7.1% and 30.1% relative to baseline (p < 0.001) and retained their scores at one year follow-up. The success rates for individual skills were consistent with the total and subtotal WST scores. The CHART Mobility sub-score improved by 3.2% over baseline (p = 0.021). Conclusions Individualized wheelchair skills training in the home environment substantially improves the advanced and total wheelchair skills capacity of experienced community-dwelling veterans with SCI but has only a small impact on participation. PMID:28002472

The Impact of Living in a Care Home on the Health and Wellbeing of Spinal Cord Injured People

PubMed Central

Smith, Brett; Caddick, Nick

2015-01-01

In the UK, 20% of people with spinal cord injury (SCI) are discharged from rehabilitation into an elderly care home. Despite this, and knowledge that the home is central to health and wellbeing, little research has examined the impact of being in care homes on the health and wellbeing of people with SCI. The purpose of this study was to address this gap. Twenty adults who lived in care homes or had done so recently for over two years were interviewed in-depth. Qualitative data were analyzed using inductive thematic analysis. Analyses revealed that living in a care home environment severely damages quality of life, physical health and psychological wellbeing in the short and long-term. Reasons why quality of life, health, and wellbeing were damaged are identified. These included a lack of freedom, control, and flexibility, inability to participate in community life, inability to sustain relationships, safety problems, restricted participation in work and leisure time physical activity, lack of meaning, self-expression, and a future, loneliness, difficulties with the re-housing process, depression, and suicidal thoughts and actions. It is concluded that for people with SCI, the care home environment violates social dignity, is oppressive, and denies human rights. Implications for housing and health care policies are also offered. PMID:25884273

The impact of living in a care home on the health and wellbeing of spinal cord injured people.

PubMed

Smith, Brett; Caddick, Nick

2015-04-15

In the UK, 20% of people with spinal cord injury (SCI) are discharged from rehabilitation into an elderly care home. Despite this, and knowledge that the home is central to health and wellbeing, little research has examined the impact of being in care homes on the health and wellbeing of people with SCI. The purpose of this study was to address this gap. Twenty adults who lived in care homes or had done so recently for over two years were interviewed in-depth. Qualitative data were analyzed using inductive thematic analysis. Analyses revealed that living in a care home environment severely damages quality of life, physical health and psychological wellbeing in the short and long-term. Reasons why quality of life, health, and wellbeing were damaged are identified. These included a lack of freedom, control, and flexibility, inability to participate in community life, inability to sustain relationships, safety problems, restricted participation in work and leisure time physical activity, lack of meaning, self-expression, and a future, loneliness, difficulties with the re-housing process, depression, and suicidal thoughts and actions. It is concluded that for people with SCI, the care home environment violates social dignity, is oppressive, and denies human rights. Implications for housing and health care policies are also offered.

DEMONSTRATION BULLETIN: SOLIDIFICATION/STABILIZATION PROCESS, Hazcon, Inc.

EPA Science Inventory

The solidification/stabilization technology mixes hazardous wastes, cement, water and an additive called Chloranan. Chloranan, a nontoxic chemical, encapsulates organic molecules, rendering them ineffective in retarding or inhibiting solidification. This treatment technol...

Mexican Space Weather Service (SCiESMEX)

NASA Astrophysics Data System (ADS)

Gonzalez-Esparza, J. A.; De la Luz, V.; Corona-Romero, P.; Mejia-Ambriz, J. C.; Gonzalez, L. X.; Sergeeva, M. A.; Romero-Hernandez, E.; Aguilar-Rodriguez, E.

2017-01-01

Legislative modifications of the General Civil Protection Law in Mexico in 2014 included specific references to space hazards and space weather phenomena. The legislation is consistent with United Nations promotion of international engagement and cooperation on space weather awareness, studies, and monitoring. These internal and external conditions motivated the creation of a space weather service in Mexico. The Mexican Space Weather Service (SCiESMEX in Spanish) (www.sciesmex.unam.mx) was initiated in October 2014 and is operated by the Institute of Geophysics at the Universidad Nacional Autonoma de Mexico (UNAM). SCiESMEX became a Regional Warning Center of the International Space Environment Services (ISES) in June 2015. We present the characteristics of the service, some products, and the initial actions for developing a space weather strategy in Mexico. The service operates a computing infrastructure including a web application, data repository, and a high-performance computing server to run numerical models. SCiESMEX uses data of the ground-based instrumental network of the National Space Weather Laboratory (LANCE), covering solar radio burst emissions, solar wind and interplanetary disturbances (by interplanetary scintillation observations), geomagnetic measurements, and analysis of the total electron content (TEC) of the ionosphere (by employing data from local networks of GPS receiver stations).

ScyFlow: An Environment for the Visual Specification and Execution of Scientific Workflows

NASA Technical Reports Server (NTRS)

McCann, Karen M.; Yarrow, Maurice; DeVivo, Adrian; Mehrotra, Piyush

2004-01-01

With the advent of grid technologies, scientists and engineers are building more and more complex applications to utilize distributed grid resources. The core grid services provide a path for accessing and utilizing these resources in a secure and seamless fashion. However what the scientists need is an environment that will allow them to specify their application runs at a high organizational level, and then support efficient execution across any given set or sets of resources. We have been designing and implementing ScyFlow, a dual-interface architecture (both GUT and APT) that addresses this problem. The scientist/user specifies the application tasks along with the necessary control and data flow, and monitors and manages the execution of the resulting workflow across the distributed resources. In this paper, we utilize two scenarios to provide the details of the two modules of the project, the visual editor and the runtime workflow engine.

The Impact of Congruency between Preferred and Actual Learning Environments on Tenth Graders' Science Literacy in Taiwan

ERIC Educational Resources Information Center

Chang, Chun-Yen; Yeh, Ting-Kuang; Lin, Chun-Yen; Chang, Yueh-Hsia; Chen, Chia-Li D.

2010-01-01

This study explored the effects of congruency between preferred and actual learning environment (PLE & ALE) perceptions on students' science literacy in terms of science concepts, attitudes toward science, and the understanding of the nature of science in an innovative curriculum of High Scope Project, namely Sci-Tech Mind and Humane Heart…

Longitudinal Recovery and Reduced Costs After 120 Sessions of Locomotor Training for Motor Incomplete Spinal Cord Injury.

PubMed

Morrison, Sarah A; Lorenz, Douglas; Eskay, Carol P; Forrest, Gail F; Basso, D Michele

2018-03-01

To determine the impact of long-term, body weight-supported locomotor training after chronic, incomplete spinal cord injury (SCI), and to estimate the health care costs related to lost recovery potential and preventable secondary complications that may have occurred because of visit limits imposed by insurers. Prospective observational cohort with longitudinal follow-up. Eight outpatient rehabilitation centers that participate in the Christopher & Dana Reeve Foundation NeuroRecovery Network (NRN). Individuals with motor incomplete chronic SCI (American Spinal Injury Association Impairment Scale C or D; N=69; 0.1-45y after SCI) who completed at least 120 NRN physical therapy sessions. Manually assisted locomotor training (LT) in a body weight-supported treadmill environment, overground standing and stepping activities, and community integration tasks. International Standards for Neurological Classification of Spinal Cord Injury motor and sensory scores, orthostatic hypotension, bowel/bladder/sexual function, Spinal Cord Injury Functional Ambulation Inventory (SCI-FAI), Berg Balance Scale, Modified Functional Reach, 10-m walk test, and 6-minute walk test. Longitudinal outcome measure collection occurred every 20 treatments and at 6- to 12-month follow-up after discharge from therapy. Significant improvement occurred for upper and lower motor strength, functional activities, psychological arousal, sensation of bowel movement, and SCI-FAI community ambulation. Extended training enabled minimal detectable changes at 60, 80, 100, and 120 sessions. After detectable change occurred, it was sustained through 120 sessions and continued 6 to 12 months after treatment. Delivering at least 120 sessions of LT improves recovery from incomplete chronic SCI. Because walking reduces rehospitalization, LT delivered beyond the average 20-session insurance limit can reduce rehospitalizations and long-term health costs. Copyright © 2018 American Congress of Rehabilitation Medicine. Published by Elsevier Inc. All rights reserved.

Suspect/Counterfeit Items Information Guide for Subcontractors/Suppliers

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tessmar, Nancy D.; Salazar, Michael J.

2012-09-18

Counterfeiting of industrial and commercial grade items is an international problem that places worker safety, program objectives, expensive equipment, and security at risk. In order to prevent the introduction of Suspect/Counterfeit Items (S/CI), this information sheet is being made available as a guide to assist in the implementation of S/CI awareness and controls, in conjunction with subcontractor's/supplier's quality assurance programs. When it comes to counterfeit goods, including industrial materials, items, and equipment, no market is immune. Some manufactures have been known to misrepresent their products and intentionally use inferior materials and processes to manufacture substandard items, whose properties can significantlymore » cart from established standards and specifications. These substandard items termed by the Department of Energy (DOE) as S/CI, pose immediate and potential threats to the safety of DOE and contractor workers, the public, and the environment. Failure of certain systems and processes caused by an S/CI could also have national security implications at Los Alamos National Laboratory (LANL). Nuclear Safety Rules (federal Laws), DOE Orders, and other regulations set forth requirements for DOE contractors to implement effective controls to assure that items and services meet specified requirements. This includes techniques to implement and thereby minimizing the potential threat of entry of S/CI to LANL. As a qualified supplier of goods or services to the LANL, your company will be required to establish and maintain effective controls to prevent the introduction of S/CI to LANL. This will require that your company warrant that all items (including their subassemblies, components, and parts) sold to LANL are genuine (i.e. not counterfeit), new, and unused, and conform to the requirements of the LANL purchase orders/contracts unless otherwise approved in writing to the Los Alamos National Security (LANS) contract administrator/procurements specialist.« less

Changes in Gene Expression and Metabolism in the Testes of the Rat following Spinal Cord Injury

PubMed Central

Fortune, Ryan D.; Grill, Raymond J.; Beeton, Christine; Tanner, Mark; Huq, Redwan

2017-01-01

Abstract Spinal cord injury (SCI) results in devastating changes to almost all aspects of a patient's life. In addition to a permanent loss of sensory and motor function, males also will frequently exhibit a profound loss of fertility through poorly understood mechanisms. We demonstrate that SCI causes measureable pathology in the testis both acutely (24 h) and chronically up to 1.5 years post-injury, leading to loss in sperm motility and viability. SCI has been shown in humans and rats to induce leukocytospermia, with the presence of inflammatory cytokines, anti-sperm antibodies, and reactive oxygen species found within the ejaculate. Using messenger RNA and metabolomic assessments, we describe molecular and cellular changes that occur within the testis of adult rats over an acute to chronic time period. From 24 h, 72 h, 28 days, and 90 days post-SCI, the testis reveal a distinct time course of pathological events. The testis show an acute drop in normal sexual organ processes, including testosterone production, and establishment of a pro-inflammatory environment. This is followed by a subacute initiation of an innate immune response and loss of cell cycle regulation, possibly due to apoptosis within the seminiferous tubules. At 1.5 years post-SCI, there is a chronic low level immune response as evidenced by an elevation in T cells. These data suggest that SCI elicits a wide range of pathological processes within the testes, the actions of which are not restricted to the acute phase of injury but rather extend chronically, potentially through the lifetime of the subject. The multiplicity of these pathological events suggest a single therapeutic intervention is unlikely to be successful. PMID:27750479

Predict-first experimental analysis using automated and integrated magnetohydrodynamic modeling

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lyons, B. C.; Paz-Soldan, C.; Meneghini, O.

An integrated-modeling workflow has been developed in this paper for the purpose of performing predict-first analysis of transient-stability experiments. Starting from an existing equilibrium reconstruction from a past experiment, the workflow couples together the EFIT Grad-Shafranov solver [L. Lao et al., Fusion Sci. Technol. 48, 968 (2005)], the EPED model for the pedestal structure [P. B. Snyder et al., Phys. Plasmas 16, 056118 (2009)], and the NEO drift-kinetic-equation solver [E. A. Belli and J. Candy, Plasma Phys. Controlled Fusion 54, 015015 (2012)] (for bootstrap current calculations) in order to generate equilibria with self-consistent pedestal structures as the plasma shape andmore » various scalar parameters (e.g., normalized β, pedestal density, and edge safety factor [q 95]) are changed. These equilibria are then analyzed using automated M3D-C1 extended-magnetohydrodynamic modeling [S. C. Jardin et al., Comput. Sci. Discovery 5, 014002 (2012)] to compute the plasma response to three-dimensional magnetic perturbations. This workflow was created in conjunction with a DIII-D experiment examining the effect of triangularity on the 3D plasma response. Several versions of the workflow were developed, and the initial ones were used to help guide experimental planning (e.g., determining the plasma current necessary to maintain the constant edge safety factor in various shapes). Subsequent validation with the experimental results was then used to revise the workflow, ultimately resulting in the complete model presented here. We show that quantitative agreement was achieved between the M3D-C1 plasma response calculated for equilibria generated by the final workflow and equilibria reconstructed from experimental data. A comparison of results from earlier workflows is used to show the importance of properly matching certain experimental parameters in the generated equilibria, including the normalized β, pedestal density, and q 95. On the other hand, the details of the pedestal current did not significantly impact the plasma response in these equilibria. A comparison to the experimentally measured plasma response shows mixed agreement, indicating that while the equilibria are predicted well, additional analysis tools may be needed. In conclusion, we note the implications that these results have for the success of future predict-first studies, particularly the need for scans of uncertain parameters and for close collaboration between experimentalists and theorists.« less

Predict-first experimental analysis using automated and integrated magnetohydrodynamic modeling

DOE PAGES

Lyons, B. C.; Paz-Soldan, C.; Meneghini, O.; ...

2018-05-07

An integrated-modeling workflow has been developed in this paper for the purpose of performing predict-first analysis of transient-stability experiments. Starting from an existing equilibrium reconstruction from a past experiment, the workflow couples together the EFIT Grad-Shafranov solver [L. Lao et al., Fusion Sci. Technol. 48, 968 (2005)], the EPED model for the pedestal structure [P. B. Snyder et al., Phys. Plasmas 16, 056118 (2009)], and the NEO drift-kinetic-equation solver [E. A. Belli and J. Candy, Plasma Phys. Controlled Fusion 54, 015015 (2012)] (for bootstrap current calculations) in order to generate equilibria with self-consistent pedestal structures as the plasma shape andmore » various scalar parameters (e.g., normalized β, pedestal density, and edge safety factor [q 95]) are changed. These equilibria are then analyzed using automated M3D-C1 extended-magnetohydrodynamic modeling [S. C. Jardin et al., Comput. Sci. Discovery 5, 014002 (2012)] to compute the plasma response to three-dimensional magnetic perturbations. This workflow was created in conjunction with a DIII-D experiment examining the effect of triangularity on the 3D plasma response. Several versions of the workflow were developed, and the initial ones were used to help guide experimental planning (e.g., determining the plasma current necessary to maintain the constant edge safety factor in various shapes). Subsequent validation with the experimental results was then used to revise the workflow, ultimately resulting in the complete model presented here. We show that quantitative agreement was achieved between the M3D-C1 plasma response calculated for equilibria generated by the final workflow and equilibria reconstructed from experimental data. A comparison of results from earlier workflows is used to show the importance of properly matching certain experimental parameters in the generated equilibria, including the normalized β, pedestal density, and q 95. On the other hand, the details of the pedestal current did not significantly impact the plasma response in these equilibria. A comparison to the experimentally measured plasma response shows mixed agreement, indicating that while the equilibria are predicted well, additional analysis tools may be needed. In conclusion, we note the implications that these results have for the success of future predict-first studies, particularly the need for scans of uncertain parameters and for close collaboration between experimentalists and theorists.« less

Predict-first experimental analysis using automated and integrated magnetohydrodynamic modeling

NASA Astrophysics Data System (ADS)

Lyons, B. C.; Paz-Soldan, C.; Meneghini, O.; Lao, L. L.; Weisberg, D. B.; Belli, E. A.; Evans, T. E.; Ferraro, N. M.; Snyder, P. B.

2018-05-01

An integrated-modeling workflow has been developed for the purpose of performing predict-first analysis of transient-stability experiments. Starting from an existing equilibrium reconstruction from a past experiment, the workflow couples together the EFIT Grad-Shafranov solver [L. Lao et al., Fusion Sci. Technol. 48, 968 (2005)], the EPED model for the pedestal structure [P. B. Snyder et al., Phys. Plasmas 16, 056118 (2009)], and the NEO drift-kinetic-equation solver [E. A. Belli and J. Candy, Plasma Phys. Controlled Fusion 54, 015015 (2012)] (for bootstrap current calculations) in order to generate equilibria with self-consistent pedestal structures as the plasma shape and various scalar parameters (e.g., normalized β, pedestal density, and edge safety factor [q95]) are changed. These equilibria are then analyzed using automated M3D-C1 extended-magnetohydrodynamic modeling [S. C. Jardin et al., Comput. Sci. Discovery 5, 014002 (2012)] to compute the plasma response to three-dimensional magnetic perturbations. This workflow was created in conjunction with a DIII-D experiment examining the effect of triangularity on the 3D plasma response. Several versions of the workflow were developed, and the initial ones were used to help guide experimental planning (e.g., determining the plasma current necessary to maintain the constant edge safety factor in various shapes). Subsequent validation with the experimental results was then used to revise the workflow, ultimately resulting in the complete model presented here. We show that quantitative agreement was achieved between the M3D-C1 plasma response calculated for equilibria generated by the final workflow and equilibria reconstructed from experimental data. A comparison of results from earlier workflows is used to show the importance of properly matching certain experimental parameters in the generated equilibria, including the normalized β, pedestal density, and q95. On the other hand, the details of the pedestal current did not significantly impact the plasma response in these equilibria. A comparison to the experimentally measured plasma response shows mixed agreement, indicating that while the equilibria are predicted well, additional analysis tools may be needed. Finally, we note the implications that these results have for the success of future predict-first studies, particularly the need for scans of uncertain parameters and for close collaboration between experimentalists and theorists.

Otolith Asymmetry and kinetotic Behaviour of Fish in Parabolic Flights and under simulated Parabolic Flight "Micro"Gravity - a Drop-Tower Experiment

NASA Astrophysics Data System (ADS)

Knie, M.; Hilbig, R.; Anken, R.

We have shown earlier that some fish of a given batch reveal motion sickness a kinetosis at the transition from earth gravity to diminished gravity The percentual ratios of the various types of behaviour normal swimming and kinetotic swimming kinetotic specimens revealed looping responses LR or spinning movements SM however highly differed depending on the quality of diminished gravity Anken and Hilbig Microgravity Sci Technol 15 52-57 2004 Whereas kinetoses were exhibited by some 90 of the individuals who had experienced flights at high quality microgravity HQM 10-6g ZARM drop-tower only some 15-25 depending on the batch of all animals had shown a kinetotic behaviour during parabolic aircraft flights PFs low quality microgravity LQM 0 03-0 05g Probably LQM is sufficient for most fish to be perceived - in relation to the individual shape or weight of otoliths and thus the performance of the vestibular system - and used as a cue for postural control In striking contrast to the results gained using PF specimens according to which otolith asymmetry differences in the size and calcium incorporation of the inner ear stones between the left and right side of the body was significantly higher in kinetotic specimens as compared to normally swimming fish a comparable asymmetry between the kinetotically and normally swimming drop-tower samples could statistically not be verified Anken et al Adv Space Res submitted The present study was designed to further elucidate the role of otolith asymmetry concerning an individually different

State of the art on granular sludge by using bibliometric analysis.

PubMed

Zheng, Tianlong; Li, Pengyu; Wu, Wenjun; Liu, Jianguo; Shi, Zhining; Guo, Xuesong; Liu, Junxin

2018-04-01

With rapid industrialization and urbanization in the nineteenth century, the activated sludge process (ASP) has experienced significant steps forward in the face of greater awareness of and sensitivity toward water-related environmental problems. Compared with conventional flocculent ASP, the major advantages of granular sludge are characterized by space saving and resource recovery, where the methane and hydrogen recovery in anaerobic granular and 50% more space saving, 30-50% of energy consumption reduction, 75% of footprint cutting, and even alginate recovery in aerobic granular. Numerous engineers and scientists have made great efforts to explore the superiority over the last 40 years. Therefore, a bibliometric analysis was desired to trace the global trends of granular sludge research from 1992 to 2016 indexed in the SCI-EXPANDED. Articles were published in 276 journals across 44 subject categories spanning 1420 institutes across 68 countries. Bioresource Technology (293, 11.9%), Water Research (235, 9.6%), and Applied Microbiology and Biotechnology (127, 5.2%) dominated in top three journals. The Engineering (991, 40.3%), China (906, 36.9%), and Harbin Inst Technol, China (114, 4.6%) were the most productive subject category, country, and institution, respectively. The hotspot is the emerging techniques depended on granular reactors in response to the desired removal requirements and bio-energy production (primarily in anaerobic granular sludge). In view of advanced and novel bio-analytical methods, the characteristics, functions, and mechanisms for microbial granular were further revealed in improving and innovating the granulation techniques. Therefore, a promising technique armed with strengthened treatment efficiency and efficient resource and bio-energy recovery can be achieved.

Quantification of oxide particle composition in model oxide dispersion strengthened steel alloys.

PubMed

London, A J; Lozano-Perez, S; Moody, M P; Amirthapandian, S; Panigrahi, B K; Sundar, C S; Grovenor, C R M

2015-12-01

Oxide dispersion strengthened ferritic steels (ODS) are being considered for structural components of future designs of fission and fusion reactors because of their impressive high-temperature mechanical properties and resistance to radiation damage, both of which arise from the nanoscale oxide particles they contain. Because of the critical importance of these nanoscale phases, significant research activity has been dedicated to analysing their precise size, shape and composition (Odette et al., Annu. Rev. Mater. Res. 38 (2008) 471-503 [1]; Miller et al., Mater. Sci. Technol. 29(10) (2013) 1174-1178 [2]). As part of a project to develop new fuel cladding alloys in India, model ODS alloys have been produced with the compositions, Fe-0.3Y2O3, Fe-0.2Ti-0.3Y2O3 and Fe-14Cr-0.2Ti-0.3Y2O3. The oxide particles in these three model alloys have been studied by APT in their as-received state and following ion irradiation (as a proxy for neutron irradiation) at various temperatures. In order to adequately quantify the composition of the oxide clusters, several difficulties must be managed, including issues relating to the chemical identification (ranging and variable peak-overlaps); trajectory aberrations and chemical structure; and particle sizing. This paper presents how these issues can be addressed by the application of bespoke data analysis tools and correlative microscopy. A discussion follows concerning the achievable precision in these measurements, with reference to the fundamental limiting factors. Copyright © 2015 Elsevier B.V. All rights reserved.

On non-equilibrium atmospheric pressure plasma jets and plasma bullet

NASA Astrophysics Data System (ADS)

Lu, Xinpei

2012-10-01

Because of the enhanced plasma chemistry, atmospheric pressure nonequilibrium plasmas (APNPs) have been widely studied for several emerging applications such as biomedical applications. For the biomedical applications, plasma jet devices, which generate plasma in open space (surrounding air) rather than in confined discharge gaps only, have lots of advantages over the traditional dielectric barrier discharge (DBD) devices. For example, it can be used for root canal disinfection, which can't be realized by the traditional plasma device. On the other hand, currently, the working gases of most of the plasma jet devices are noble gases or the mixtures of the noble gases with small amount of O2, or air. If ambient air is used as the working gas, several serious difficulties are encountered in the plasma generation process. Amongst these are high gas temperatures and disrupting instabilities. In this presentation, firstly, a brief review of the different cold plasma jets developed to date is presented. Secondly, several different plasma jet devices developed in our lab are reported. The effects of various parameters on the plasma jets are discussed. Finally, one of the most interesting phenomena of APNP-Js, the plasma bullet is discussed and its behavior is described. References: [1] X. Lu, M. Laroussi, V. Puech, Plasma Sources Sci. Technol. 21, 034005 (2012); [2] Y. Xian, X. Lu, S. Wu, P. Chu, and Y. Pan, Appl. Phys. Lett. 100, 123702 (2012); [3] X. Pei, X. Lu, J. Liu, D. Liu, Y. Yang, K. Ostrikov, P. Chu, and Y. Pan, J. Phys. D 45, 165205 (2012).

Iodine-frequency-stabilized laser diode and displacement-measuring interferometer based on sinusoidal phase modulation

NASA Astrophysics Data System (ADS)

Duong, Quang Anh; Vu, Thanh Tung; Higuchi, Masato; Wei, Dong; Aketagawa, Masato

2018-06-01

We propose a sinusoidal phase modulation method to achieve both the frequency stabilization of an external-cavity laser diode (ECLD) to an 127I2 saturated absorption transition near 633 nm and displacement measurement using a Mach–Zehnder interferometer. First, the frequency of the ECLD is stabilized to the b 21 hyperfine component of the P(33) 6-3 transition of 127I2 by combining sinusoidal phase modulation by an electro-optic modulator and frequency modulation spectroscopy by chopping the pump beam using an acousto-optic modulator. Even though a small modulation index of m  =  3.768 rad is utilized, a relative frequency stability of 10‑11 order is obtained over a sampling time of 400 s. Secondly, the frequency-stabilized ECLD is applied as a light source to a Mach–Zehnder interferometer. From the two consecutive modulation harmonics (second and third orders) involved in the interferometer signal, the displacement of the moving mirror is determined for four optical path differences (L 0  =  100, 200, 500, and 1000 mm). The measured modulation indexes for the four optical path differences coincide with the designated value (3.768 rad) within 0.5%. Compared with the sinusoidal frequency modulation Michelson interferometer (Vu et al 2016 Meas. Sci. Technol. 27 105201) which was demonstrated by some of the same authors of this paper, the phase modulation Mach–Zhender interferometer could fix the modulation index to a constant value for the four optical path differences. In this report, we discuss the measurement principle, experimental system, and results.

Measuring time of flight of fusion products in an inertial electrostatic confinement fusion device for spatial profiling of fusion reactions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Donovan, D. C.; Boris, D. R.; Kulcinski, G. L.

2013-03-15

A new diagnostic has been developed that uses the time of flight (TOF) of the products from a nuclear fusion reaction to determine the location where the fusion reaction occurred. The TOF diagnostic uses charged particle detectors on opposing sides of the inertial electrostatic confinement (IEC) device that are coupled to high resolution timing electronics to measure the spatial profile of fusion reactions occurring between the two charged particle detectors. This diagnostic was constructed and tested by the University of Wisconsin-Madison Inertial Electrostatic Confinement Fusion Group in the IEC device, HOMER, which accelerates deuterium ions to fusion relevant energies inmore » a high voltage ({approx}100 kV), spherically symmetric, electrostatic potential well [J. F. Santarius, G. L. Kulcinski, R. P. Ashley, D. R. Boris, B. B. Cipiti, S. K. Murali, G. R. Piefer, R. F. Radel, T. E. Radel, and A. L. Wehmeyer, Fusion Sci. Technol. 47, 1238 (2005)]. The TOF diagnostic detects the products of D(d,p)T reactions and determines where along a chord through the device the fusion event occurred. The diagnostic is also capable of using charged particle spectroscopy to determine the Doppler shift imparted to the fusion products by the center of mass energy of the fusion reactants. The TOF diagnostic is thus able to collect spatial profiles of the fusion reaction density along a chord through the device, coupled with the center of mass energy of the reactions occurring at each location. This provides levels of diagnostic detail never before achieved on an IEC device.« less

Reconstruction of the static magnetic field of a magnetron

NASA Astrophysics Data System (ADS)

Krüger, Dennis; Köhn, Kevin; Gallian, Sara; Brinkmann, Ralf Peter

2018-06-01

The simulation of magnetron discharges requires a quantitatively correct mathematical model of the magnetic field structure. This study presents a method to construct such a model on the basis of a spatially restricted set of experimental data and a plausible a priori assumption on the magnetic field configuration. The example in focus is that of a planar circular magnetron. The experimental data are Hall probe measurements of the magnetic flux density in an accessible region above the magnetron plane [P. D. Machura et al., Plasma Sources Sci. Technol. 23, 065043 (2014)]. The a priori assumption reflects the actual design of the device, and it takes the magnetic field emerging from a center magnet of strength m C and vertical position d C and a ring magnet of strength m R , vertical position d R , and radius R. An analytical representation of the assumed field configuration can be formulated in terms of generalized hypergeometric functions. Fitting the ansatz to the experimental data with a least square method results in a fully specified analytical field model that agrees well with the data inside the accessible region and, moreover, is physically plausible in the regions outside of it. The outcome proves superior to the result of an alternative approach which starts from a multimode solution of the vacuum field problem formulated in terms of polar Bessel functions and vertical exponentials. As a first application of the obtained field model, typical electron and ion Larmor radii and the gradient and curvature drift velocities of the electron guiding center are calculated.

Relativistic R -matrix calculations for the electron-impact excitation of neutral molybdenum

NASA Astrophysics Data System (ADS)

Smyth, R. T.; Johnson, C. A.; Ennis, D. A.; Loch, S. D.; Ramsbottom, C. A.; Ballance, C. P.

2017-10-01

A recent PISCES-B Mod experiment [Nishijima et al., J. Phys. B 43, 225701 (2010), 10.1088/0953-4075/43/22/225701] has revealed up to a factor of 5 discrepancy between measurement and the two existing theoretical models [Badnell et al., J. Phys. B 29, 3683 (1996), 10.1088/0953-4075/29/16/014; Bartschat et al., J. Phys. B 35, 2899 (2002), 10.1088/0953-4075/35/13/305], providing important diagnostics for Mo i. In the following paper we address this issue by employing a relativistic atomic structure and R -matrix scattering calculations to improve upon the available models for future applications and benchmark results against a recent Compact Toroidal Hybrid experiment [Hartwell et al., Fusion Sci. Technol. 72, 76 (2017), 10.1080/15361055.2017.1291046]. We determine the atomic structure of Mo i using grasp0, which implements the multiconfigurational Dirac-Fock method. Fine structure energies and radiative transition rates are presented and compared to existing experimental and theoretical values. The electron-impact excitation of Mo i is investigated using the relativistic R -matrix method and the parallel versions of the Dirac atomic R -matrix codes. Electron-impact excitation cross sections are presented and compared to the few available theoretical cross sections. Throughout, our emphasis is on improving the results for the z 1,2,3o5P →a S52,z 2,3,4o7P → a S73 and y 2,3,4o7P → a S73 electric dipole transitions of particular relevance for diagnostic work.

Measurements and modeling of the impact of weak magnetic fields on the plasma properties of a planar slot antenna driven plasma source

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yoshikawa, Jun, E-mail: jun.yoshikawa@tel.com; Susa, Yoshio; Ventzek, Peter L. G.

The radial line slot antenna plasma source is a type of surface wave plasma source driven by a planar slot antenna. Microwave power is transmitted through a slot antenna structure and dielectric window to a plasma characterized by a generation zone adjacent to the window and a diffusion zone that contacts a substrate. The diffusion zone is characterized by a very low electron temperature. This renders the source useful for soft etch applications and thin film deposition processes requiring low ion energy. Another property of the diffusion zone is that the plasma density tends to decrease from the axis tomore » the walls under the action of ambipolar diffusion at distances far from where the plasma is generated. A previous simulation study [Yoshikawa and. Ventzek, J. Vac. Sci. Technol. A 31, 031306 (2013)] predicted that the anisotropy in transport parameters due to weak static magnetic fields less than 50 G could be leveraged to manipulate the plasma profile in the radial direction. These simulations motivated experimental tests in which weak magnetic fields were applied to a radial line slot antenna source. Plasma absorption probe measurements of electron density and etch rate showed that the magnetic fields remote from the wafer were able to manipulate both parameters. A summary of these results is presented in this paper. Argon plasma simulation trends are compared with experimental plasma and etch rate measurements. A test of the impact of magnetic fields on charge up damage showed no perceptible negative effect.« less

A status report of the multipurpose superconducting electron cyclotron resonance ion source.

PubMed

Ciavola, G; Gammino, S; Barbarino, S; Celona, L; Consoli, F; Gallo, G; Maimone, F; Mascali, D; Passarello, S; Galatà, A; Tinschert, K; Spaedtke, P; Lang, R; Maeder, J; Rossbach, J; Koivisto, H; Savonen, M; Koponen, T; Suominen, P; Ropponen, T; Baruè, C; Lechartier, M; Beijers, J P M; Brandenburg, S; Kremers, H R; Vanrooyen, D; Kuchler, D; Scrivens, R; Schachter, L; Dobrescu, S; Stiebing, K

2008-02-01

Intense heavy ion beam production with electron cyclotron resonance (ECR) ion sources is a common requirement for many of the accelerators under construction in Europe and elsewhere. An average increase of about one order of magnitude per decade in the performance of ECR ion sources was obtained up to now since the time of pioneering experiment of R. Geller at CEA, Grenoble, and this trend is not deemed to get the saturation at least in the next decade, according to the increased availability of powerful magnets and microwave generators. Electron density above 10(13) cm(-3) and very high current of multiply charged ions are expected with the use of 28 GHz microwave heating and of an adequate plasma trap, with a B-minimum shape, according to the high B mode concept [S. Gammino and G. Ciavola, Plasma Sources Sci. Technol. 5, 19 (1996)]. The MS-ECRIS ion source has been designed following this concept and its construction is underway at GSI, Darmstadt. The project is the result of the cooperation of nine European institutions with the partial funding of EU through the sixth Framework Programme. The contribution of different institutions has permitted to build in 2006-2007 each component at high level of expertise. The description of the major components will be given in the following with a view on the planning of the assembly and commissioning phase to be carried out in fall 2007. An outline of the experiments to be done with the MS-ECRIS source in the next two years will be presented.

Production of internal transport barriers via self-generated mean flows in Alcator C-Moda)

NASA Astrophysics Data System (ADS)

Fiore, C. L.; Ernst, D. R.; Podpaly, Y. A.; Mikkelsen, D.; Howard, N. T.; Lee, Jungpyo; Reinke, M. L.; Rice, J. E.; Hughes, J. W.; Ma, Y.; Rowan, W. L.; Bespamyatnov, I.

2012-05-01

New results suggest that changes observed in the intrinsic toroidal rotation influence the internal transport barrier (ITB) formation in the Alcator C-Mod tokamak [E. S. Marmar and Alcator C-Mod group, Fusion Sci. Technol. 51, 261 (2007)]. These arise when the resonance for ion cyclotron range of frequencies (ICRF) minority heating is positioned off-axis at or outside of the plasma half-radius. These ITBs form in a reactor relevant regime, without particle or momentum injection, with Ti ≈ Te, and with monotonic q profiles (qmin < 1). C-Mod H-mode plasmas exhibit strong intrinsic co-current rotation that increases with increasing stored energy without external drive. When the resonance position is moved off-axis, the rotation decreases in the center of the plasma resulting in a radial toroidal rotation profile with a central well which deepens and moves farther off-axis when the ICRF resonance location reaches the plasma half-radius. This profile results in strong E × B shear (>1.5 × 105 rad/s) in the region where the ITB foot is observed. Gyrokinetic analyses indicate that this spontaneous shearing rate is comparable to the linear ion temperature gradient (ITG) growth rate at the ITB location and is sufficient to reduce the turbulent particle and energy transport. New and detailed measurement of the ion temperature demonstrates that the radial profile flattens as the ICRF resonance position moves off axis, decreasing the drive for the ITG the instability as well. These results are the first evidence that intrinsic rotation can affect confinement in ITB plasmas.

Ultra-high-speed 3D astigmatic particle tracking velocimetry: application to particle-laden supersonic impinging jets

NASA Astrophysics Data System (ADS)

Buchmann, N. A.; Cierpka, C.; Kähler, C. J.; Soria, J.

2014-11-01

The paper demonstrates ultra-high-speed three-component, three-dimensional (3C3D) velocity measurements of micron-sized particles suspended in a supersonic impinging jet flow. Understanding the dynamics of individual particles in such flows is important for the design of particle impactors for drug delivery or cold gas dynamic spray processing. The underexpanded jet flow is produced via a converging nozzle, and micron-sized particles ( d p = 110 μm) are introduced into the gas flow. The supersonic jet impinges onto a flat surface, and the particle impact velocity and particle impact angle are studied for a range of flow conditions and impingement distances. The imaging system consists of an ultra-high-speed digital camera (Shimadzu HPV-1) capable of recording rates of up to 1 Mfps. Astigmatism particle tracking velocimetry (APTV) is used to measure the 3D particle position (Cierpka et al., Meas Sci Technol 21(045401):13, 2010) by coding the particle depth location in the 2D images by adding a cylindrical lens to the high-speed imaging system. Based on the reconstructed 3D particle positions, the particle trajectories are obtained via a higher-order tracking scheme that takes advantage of the high temporal resolution to increase robustness and accuracy of the measurement. It is shown that the particle velocity and impingement angle are affected by the gas flow in a manner depending on the nozzle pressure ratio and stand-off distance where higher pressure ratios and stand-off distances lead to higher impact velocities and larger impact angles.

Comparison of single bout effects of bicycle training versus locomotor training on paired reflex depression of the soleus H-reflex after motor incomplete spinal cord injury.

PubMed

Phadke, Chetan P; Flynn, Sheryl M; Thompson, Floyd J; Behrman, Andrea L; Trimble, Mark H; Kukulka, Carl G

2009-07-01

To examine paired reflex depression changes post 20-minute bout each of 2 training environments: stationary bicycle ergometer training (bicycle training) and treadmill with body weight support and manual assistance (locomotor training). Pretest-posttest repeated-measures. Locomotor laboratory. Motor incomplete SCI (n=12; mean, 44+/-16y); noninjured subjects (n=11; mean, 30.8+/-8.3y). All subjects received each type of training on 2 separate days. Paired reflex depression at different interstimulus intervals (10 s, 1 s, 500 ms, 200 ms, and 100 ms) was measured before and after both types of training. (1) Depression was significantly less post-SCI compared with noninjured subjects at all interstimulus intervals and (2) post-SCI at 100-millisecond interstimulus interval: reflex depression significantly increased postbicycle training in all SCI subjects and in the chronic and spastic subgroups (P<.05). Phase-dependent regulation of reflex excitability, essential to normal locomotion, coordinated by pre- and postsynaptic inhibitory processes (convergent action of descending and segmental inputs onto spinal circuits) is impaired post-SCI. Paired reflex depression provides a quantitative assay of inhibitory processes contributing to phase-dependent changes in reflex excitability. Because bicycle training normalized reflex depression, we propose that bicycling may have a potential role in walking rehabilitation, and future studies should examine the long-term effects on subclinical measures of reflex activity and its relationship to functional outcomes.

An area-preserving mapping in natural canonical coordinates for magnetic field line trajectories in the DIII-D tokamak

NASA Astrophysics Data System (ADS)

Punjabi, Alkesh

2009-11-01

The new approach of integrating magnetic field line trajectories in natural canonical coordinates (Punjabi and Ali 2008 Phys. Plasmas 15 122502) in divertor tokamaks is used for the DIII-D tokamak (Luxon and Davis1985 Fusion Technol. 8 441). The equilibrium EFIT data (Evans et al 2004 Phys. Rev. Lett. 92 235003, Lao et al 2005 Fusion Sci. Technol. 48 968) for the DIII-D tokamak shot 115467 at 3000 ms is used to construct the equilibrium generating function (EGF) for the DIII-D in natural canonical coordinates. The EGF gives quite an accurate representation of the closed and open equilibrium magnetic surfaces near the separatrix, the separatrix, the position of the X-point and the poloidal magnetic flux inside the ideal separatrix in the DIII-D. The equilibrium safety factor q from the EGF is somewhat smaller than the DIII-D EFIT q profile. The equilibrium safety factor is calculated from EGF as described in the previous paper (Punjabi and Ali 2008 Phys. Plasmas 15 122502). Here the safety factor for the open surfaces in the DIII-D is calculated. A canonical transformation is used to construct a symplectic mapping for magnetic field line trajectories in the DIII-D in natural canonical coordinates. The map is explored in more detail in this work, and is used to calculate field line trajectories in the DIII-D tokamak. The continuous analogue of the map does not distort the DIII-D magnetic surfaces in different toroidal planes between successive iterations of the map. The map parameter k can represent effects of magnetic asymmetries in the DIII-D. These effects in the DIII-D are illustrated. The DIII-D map is then used to calculate stochastic broadening of the ideal separatrix from the topological noise and field errors, the low mn, the high mn and peeling-ballooning magnetic perturbations in the DIII-D. The width of the stochastic layer scales as 1/2 power of amplitude with a maximum deviation of 6% from the Boozer-Rechester scaling (Boozer and Rechester 1978 Phys. Fluids 21 682). The loss of poloidal flux scales linearly with the amplitude of perturbation with a maximum deviation of 10% from linearity. Perturbations with higher mode numbers result in higher stochasticity. The higher the complexity and coupling in the equilibrium magnetic geometry, the closer is the scaling to the Boozer-Rechester scaling of width. The comparison of the EGF for the simple map (Punjabi et al 1992 Phys. Rev. Lett. 69 3322) with that of the DIII-D shows that the more complex the magnetic geometry and the more coupling of modes in equilibrium, the more robust or resilient is the system against the chaos-inducing, symmetry-breaking perturbations.

Army Reserve Component Personalized Empowerment Program (ARCPEP)

DTIC Science & Technology

2010-10-01

in U.S. hospitals—2007. Am J Health Syst Pharm 2008; 65:2244-64 2. Hardiker NR, Grant MJ. Barriers and facilitators that affect public engagement with eHealth services. Stud Health Technol Inform 2010; 160:13-7

Unified Scaling Law for flux pinning in practical superconductors: II. Parameter testing, scaling constants, and the Extrapolative Scaling Expression

NASA Astrophysics Data System (ADS)

Ekin, Jack W.; Cheggour, Najib; Goodrich, Loren; Splett, Jolene; Bordini, Bernardo; Richter, David

2016-12-01

A scaling study of several thousand Nb3Sn critical-current (I c) measurements is used to derive the Extrapolative Scaling Expression (ESE), a relation that can quickly and accurately extrapolate limited datasets to obtain full three-dimensional dependences of I c on magnetic field (B), temperature (T), and mechanical strain (ɛ). The relation has the advantage of being easy to implement, and offers significant savings in sample characterization time and a useful tool for magnet design. Thorough data-based analysis of the general parameterization of the Unified Scaling Law (USL) shows the existence of three universal scaling constants for practical Nb3Sn conductors. The study also identifies the scaling parameters that are conductor specific and need to be fitted to each conductor. This investigation includes two new, rare, and very large I c(B,T,ɛ) datasets (each with nearly a thousand I c measurements spanning magnetic fields from 1 to 16 T, temperatures from ˜2.26 to 14 K, and intrinsic strains from -1.1% to +0.3%). The results are summarized in terms of the general USL parameters given in table 3 of Part 1 (Ekin J W 2010 Supercond. Sci. Technol. 23 083001) of this series of articles. The scaling constants determined for practical Nb3Sn conductors are: the upper-critical-field temperature parameter v = 1.50 ± 0.04 the cross-link parameter w = 3.0 ± 0.3 and the strain curvature parameter u = 1.7 ± 0.1 (from equation (29) for b c2(ɛ) in Part 1). These constants and required fitting parameters result in the ESE relation, given by I c ( B , T , ɛ ) B = C [ b c 2 ( ɛ ) ] s ( 1 - t 1.5 ) η - μ ( 1 - t 2 ) μ b p ( 1 - b ) q with reduced magnetic field b ≡ B/B c2*(T,ɛ) and reduced temperature t ≡ T/T c*(ɛ), where: B c 2 * ( T , ɛ ) = B c 2 * ( 0 , 0 ) ( 1 - t 1.5 ) b c 2 ( ɛ ) T c * ( ɛ ) = T c * ( 0 ) [ b c 2 ( ɛ ) ] 1/3 and fitting parameters: C, B c2*(0,0), T c*(0), s, either η or μ (but not both), plus the parameters in the strain function b c2(ɛ). The pinning-force shape parameters p and q are also preferably fitted (simultaneously with the other parameters), but default values p = 0.5 and q = 2.0 also give high fitting accuracy when the range of relative magnetic fields is not extensive. Default values are also essential when the magnetic field data range is insufficient to determine p and q. The scaling constants are remarkably stable (changes less than ˜1%) with respect to different values of p and q, Nb3Sn conductor configurations, magnetic self-field corrections, and pinning-force trim values. The results demonstrate that the scaling of transport critical current holds down to the lowest temperatures measured ˜2.2 K, for both magnetic self-field corrected and uncorrected data. An initial comparison is also made between transport and magnetization scaling data in matched Nb3Sn samples and significant differences are found, especially for the upper critical field B c2*(T,ɛ), which may be a result of inhomogeneous shielding currents. In Part 3 of this topical review series (Ekin J W 2017 Supercond. Sci. Technol. at press), the smallest practical minimum dataset for extrapolating full I c(B,T,ɛ) datasets is derived. Application of the ESE relation is illustrated in several new areas, including full characterization of Nb3Sn conductors from as little as a single I c(B) curve when a few core parameters have been determined for similar conductors.

Exploring Earth and the Solar System: Educational Outreach Through NASA's Space Place, SciJinks, and Climate Kids Websites

NASA Technical Reports Server (NTRS)

Meneses, Joseph Chistopher

2012-01-01

NASA's Space Place team publishes engaging content and creates an effective environment to inspire a young audience to dare mighty things. NASA uses the Space Place, Climate Kids, and SciJinks websites to cultivate interest among elementary-school-aged children in both science and technology. During my summer internship at Jet Propulsion Laboratory I used Adobe Flash and ActionScript 3 to develop content for the Space Place, Climate Kids, and SciJinks sites. In addition, I was involved in the development process for ongoing and new projects during my internship. My involvement allowed me to follow a project from concept to design, implementation, and release. I personally worked on three projects this summer, two of which are currently in deployment. The first is a scrambled letter-tile guessing game titled Solar System Scramble. The second, Butterfrog Mix-Up, is a rotating-tile puzzle game. The third project is a unfinished prototype for a maze game.

Application of a model to analyze shoulder biomechanics in adult patients with spinal cord injury when walking with crutches in two different gait patterns.

PubMed

Perez-Rizo, Enrique; Trincado-Alonso, Fernando; Pérez-Nombela, Soraya; Del Ama-Espinosa, Antonio; Jiménez-Díaz, Fernando; Lozano-Berrio, Vicente; Gil-Agudo, Angel

2017-01-01

Specific biomechanical models have been developed to study gait using crutches. Clinical application of these models is needed in adult spinal cord injury (SCI) population walking with different patterns of gait with crutches to prevent overuse shoulder injuries. To apply a biomechanical model in a clinical environment to analyze shoulder in adult SCI patients walking with two different patterns of gait with crutches: two point reciprocal gait (RG) and swing-through gait (SG). Load cells were fixed to the distal ends and forearm cuffs of a pair of crutches. An active markers system was used for kinematics. Five cycles for each gait pattern were analyzed applying a biomechanical model of the upper limbs. Fifteen subjects with SCI were analyzed. The flexo-extension range of motion was significantly greater when using SG (p < 0.01). Similarly, the superior, posterior and medial forces were significantly stronger for SG in all 3 directions. Flexion, adduction and internal rotation torques were also greater in SG (p < 0.01). A biomechanical model was successfully applied to study shoulder biomechanics in adult patients with SCI walking with crutches in two different gait patterns. Greater loads exerted on the shoulder walking with SG were confirmed compared to RG.

Enabling Scientists: Serving Sci-Tech Library Users with Disabilities.

ERIC Educational Resources Information Center

Coonin, Bryna

2001-01-01

Discusses how librarians in scientific and technical libraries can contribute to an accessible electronic library environment for users with disabilities to ensure independent access to information. Topics include relevant assistive technologies; creating accessible Web pages; monitoring accessibility of electronic databases; preparing accessible…

Study of water quality improvements during riverbank filtration at three midwestern United States drinking water utilities

NASA Astrophysics Data System (ADS)

Weiss, W.; Bouwer, E.; Ball, W.; O'Melia, C.; Lechevallier, M.; Arora, H.; Aboytes, R.; Speth, T.

2003-04-01

Riverbank filtration (RBF) is a process during which surface water is subjected to subsurface flow prior to extraction from wells. During infiltration and soil passage, surface water is subjected to a combination of physical, chemical, and biological processes such as filtration, dilution, sorption, and biodegradation that can significantly improve the raw water quality (Tufenkji et al, 2002; Kuehn and Mueller, 2000; Kivimaki et al, 1998; Stuyfzand, 1998). Transport through alluvial aquifers is associated with a number of water quality benefits, including removal of microbes, pesticides, total and dissolved organic carbon (TOC and DOC), nitrate, and other contaminants (Hiscock and Grischek, 2002; Tufenkji et al., 2002; Ray et al, 2002; Kuehn and Mueller, 2000; Doussan et al, 1997; Cosovic et al, 1996; Juttner, 1995; Miettinen et al, 1994). In comparison to most groundwater sources, alluvial aquifers that are hydraulically connected to rivers are typically easier to exploit (shallow) and more highly productive for drinking water supplies (Doussan et al, 1997). Increased applications of RBF are anticipated as drinking water utilities strive to meet increasingly stringent drinking water regulations, especially with regard to the provision of multiple barriers for protection against microbial pathogens, and with regard to tighter regulations for disinfection by-products (DBPs), such as trihalomethanes (THMs) and haloacetic acids (HAAs). In the above context, research was conducted to document the water quality benefits during RBF at three major river sources in the mid-western United States, specifically with regard to DBP precursor organic matter and microbial pathogens. Specific objectives were to: 1. Evaluate the merits of RBF for removing/controlling DBP precursors and certain other drinking water contaminants (e.g. microorganisms). 2. Evaluate whether RBF can improve finished drinking water quality by removing and/or altering natural organic matter (NOM) in a manner that is not otherwise accomplished through conventional processes of drinking water treatment (e.g. coagulation, flocculation, sedimentation). 3. Evaluate changes in the character of NOM upon ground passage from the river to the wells. The experimental approach entailed monitoring the performance of three different RBF systems along the Ohio, Wabash, and Missouri Rivers in the Midwestern United States and involved a cooperative effort between the American Water Works Company, Inc. and Johns Hopkins University. Samples of the river source waters and the bank-filtered well waters were analyzed for a range of water quality parameters including TOC, DOC, UV-absorbance at 254-nm (UV-254), biodegradable dissolved organic carbon (BDOC), biologically assimilable organic carbon (AOC), inorganic species, DBP formation potential, and microorganisms. In the second year of the project, river waters were subjected to a bench-scale conventional treatment train consisting of coagulation, flocculation, sedimentation, glass-fiber filtration, and ozonation. The treated river waters were compared with the bank-filtered waters in terms of TOC, DOC, UV-254, and DBP formation potential. In the third and fourth years of the project, NOM from the river and well waters was characterized using the XAD-8 resin adsorption fractionation method (Leenheer, 1981; Thurman &Malcolm, 1981). XAD-8 adsorbing (hydrophobic) and non-adsorbing (hydrophilic) fractions of the river and well waters were compared with respect to DOC, UV-254, and DBP formation potential to determine whether RBF alters the character of the source water NOM upon ground passage and if so, which fractions are preferentially removed. The results demonstrate the effectiveness of RBF at removing the organic precursors to potentially carcinogenic DBPs. When compared to a bench-scale conventional treatment train optimized for turbidity removal, RBF performed as well as the treatment at one of the sites and significantly better than the treatment at the other two sites in terms of removal of organic carbon and DBP precursor material. Removals of TOC and DOC upon RBF at the three sites generally ranged from 30 to 70% compared to 20 to 50% removals upon bench-scale treatment of the river waters. Reductions in precursor material for a variety of DBP precursors for trihalomethanes, haloacetic acids, haloacetonitriles, haloketones, chloral hydrate, and chloropicrin upon RBF ranged from 50 to 100% using both the formation potential (FP) and the uniform formation conditions (UFC) tests (Standard Methods, 1998; Summers et al., 1996), while reductions upon bench-scale treatment were generally in the range of 40 to 80%. The significantly higher reductions of the DBP precursors relative to those of TOC and DOC indicate a preferential reduction upon ground passage in the NOM that reacts with chlorine to form DBPs. Upon both bench-scale conventional treatment and RBF, a shift was observed in DBP formation from the chlorinated to the more brominated species due to the removal of DOC relative to bromide upon treatment or RBF. As DOC is removed, the bromide:DOC ratio increases, leading to the formation of more brominated DBPs. The shift was more pronounced upon RBF due to the generally higher reductions in DOC. UFC testing with a constant chlorine:DOC:bromide ratio ruled out the possibility of any significant preferential removal of the NOM precursor material for the more chlorinated DBPs. These results highlight the importance of the bromide ion in the formation of DBPs in drinking water, especially in light of the higher theoretical cancer risk associated with the brominated DBPs. Risk calculations demonstrated the ability of RBF to reduce the theoretical excess cancer risk due to THMs formed upon chlorination, in all cases, and with substantially better performance than the bench-scale treatment train. The characterization studies were carried out to evaluate whether the observed removals of DBP precursor material upon RBF reflected a preferential removal of NOM of particular character. The results of this study indicate that RBF appears to be equally capable of removing material of different character. The different removal mechanisms in the subsurface (e.g. sorption, biodegradation, filtration) combine to provide similar removal of the operationally defined hydrophilic and hydrophobic fractions of organic material upon ground passage. Thus, the reductions in DBP formation upon RBF observed during the first two phases of this research are largely the result of a decrease in the NOM concentration rather than a major shift in the NOM character. Preliminary monitoring of a number of microorganisms indicates that RBF may also serve as a significant barrier for the removal of microbial contaminants, including human pathogens. The monitoring data demonstrated >3 log removal of Clostridium spores and >2 log removal of bacteriophage. Assuming that these indicator organisms can be used as surrogates for Giardia cysts and human enteric viruses, RBF at the three study sites surpassed the performance requirements in the United States for conventional coagulation, sedimentation, and filtration (e.g., 2.5 log removal for Giardia cysts and 2.0 log removal of viruses). References Cosovic, D.; Hrsak, V.; Vojvodic, V.; &Krznaric, D., 1996. Transformation of organic matter and bank filtration from a polluted stream. Wat. Res., 30:12:2921. Doussan, C.; Poitevin, G.; Ledoux, E.; &Detay, M., 1997. River bank filtration: Modeling of the changes in water chemistry with emphasis on nitrogen species, J. Contam. Hydrol., 25:129. Hiscock, K.M. &Grischek, T., 2002. Attenuation of Groundwater Pollution by Bank Filtration. Jour. Hydrol., 266:139. Juttner, F., 1995. Elimination of Terpenoid Odorous Compounds by Slow Sand and River Bank Filtration of the Ruhr River, Germany. Wat. Sci. Tech., 31:11:211. Kivimaki, A-L.; Lahti, K.; Hatva, T.; Tuominen, S.M.; &Miettinen, I.T., 1998. Removal of organic matter during bank filtration. Artificial Recharge of Groundwater (J.H. Peters, editor). A.A. Balkema. Rotterdam, Netherlands; Brookfield, VT. Kuehn, W. &Mueller, U., 2000. Riverbank filtration: an overview. Jour. AWWA, 92:12:60. Leenheer, J.A., 1981. Comprehensive Approach to Preparative Isolation and Fractionation of Dissolved Organic Carbon from Natural Waters and Wastewaters. Environ. Sci. Technol., 15:5:578. Miettinen, I.T.; Martikainen, P.J.; &Vartiainen, T., 1994. Humus Transformation at the Bank Filtration Water Plant. Wat. Sci. Tech., 30:10:179. Ray, C.; Grischek, T.; Schubert, J.; Wang, J.Z.; &Speth, T.F., 2002. A perspective of riverbank filtration. Jour. AWWA, 94:4:149. Standard Methods for the Examination of Water and Wastewater, 1998 (20th ed.). APHA, AWWA, and WEF, Washington. Stuyfzand, P.J., 1998. Fate of pollutants during artificial recharge and bank filtration in the Netherlands. Artificial Recharge of Groundwater (J.H. Peters, editor). A.A. Balkema. Rotterdam, Netherlands; Brookfield, Vermont. Summers, R.S.; Hooper, S.M.; Shukairy, H.M.; Solarik, G.; &Owen, D., 1996. Assessing DBP Yield: Uniform Formation Conditions. Jour. AWWA, 88:6:80. Thurman, E.M. &Malcolm, R.L., 1981. Preparative Isolation of Aquatic Humic Substances. Environ. Sci. Technol., 15:4:463. Tufenkji, N.; Ryan, J.N.; &Elimelech, M., 2002. The Promise of Bank Filtration. Envir. Sci. &Technol., 36:21:423A.

Estimation of Energy Expenditure for Wheelchair Users Using a Physical Activity Monitoring System.

PubMed

Hiremath, Shivayogi V; Intille, Stephen S; Kelleher, Annmarie; Cooper, Rory A; Ding, Dan

2016-07-01

To develop and evaluate energy expenditure (EE) estimation models for a physical activity monitoring system (PAMS) in manual wheelchair users with spinal cord injury (SCI). Cross-sectional study. University-based laboratory environment, a semistructured environment at the National Veterans Wheelchair Games, and the participants' home environments. Volunteer sample of manual wheelchair users with SCI (N=45). Participants were asked to perform 10 physical activities (PAs) of various intensities from a list. The PAMS consists of a gyroscope-based wheel rotation monitor (G-WRM) and an accelerometer device worn on the upper arm or on the wrist. Criterion EE using a portable metabolic cart and raw sensor data from PAMS were collected during each of these activities. Estimated EE using custom models for manual wheelchair users based on either the G-WRM and arm accelerometer (PAMS-Arm) or the G-WRM and wrist accelerometer (PAMS-Wrist). EE estimation performance for the PAMS-Arm (average error ± SD: -9.82%±37.03%) and PAMS-Wrist (-5.65%±32.61%) on the validation dataset indicated that both PAMS-Arm and PAMS-Wrist were able to estimate EE for a range of PAs with <10% error. Moderate to high intraclass correlation coefficients (ICCs) indicated that the EE estimated by PAMS-Arm (ICC3,1=.82, P<.05) and PAMS-Wrist (ICC3,1=.89, P<.05) are consistent with the criterion EE. Availability of PA monitors can assist wheelchair users to track PA levels, leading toward a healthier lifestyle. The new models we developed can estimate PA levels in manual wheelchair users with SCI in laboratory and community settings. Copyright © 2016 American Congress of Rehabilitation Medicine. Published by Elsevier Inc. All rights reserved.

Training wheelchair navigation in immersive virtual environments for patients with spinal cord injury - end-user input to design an effective system.

PubMed

Nunnerley, Joanne; Gupta, Swati; Snell, Deborah; King, Marcus

2017-05-01

A user-centred design was used to develop and test the feasibility of an immersive 3D virtual reality wheelchair training tool for people with spinal cord injury (SCI). A Wheelchair Training System was designed and modelled using the Oculus Rift headset and a Dynamic Control wheelchair joystick. The system was tested by clinicians and expert wheelchair users with SCI. Data from focus groups and individual interviews were analysed using a general inductive approach to thematic analysis. Four themes emerged: Realistic System, which described the advantages of a realistic virtual environment; a Wheelchair Training System, which described participants' thoughts on the wheelchair training applications; Overcoming Resistance to Technology, the obstacles to introducing technology within the clinical setting; and Working outside the Rehabilitation Bubble which described the protective hospital environment. The Oculus Rift Wheelchair Training System has the potential to provide a virtual rehabilitation setting which could allow wheelchair users to learn valuable community wheelchair use in a safe environment. Nausea appears to be a side effect of the system, which will need to be resolved before this can be a viable clinical tool. Implications for Rehabilitation Immersive virtual reality shows promising benefit for wheelchair training in a rehabilitation setting. Early engagement with consumers can improve product development.

Facilitators and barriers to social and community participation following spinal cord injury.

PubMed

Barclay, Linda; McDonald, Rachael; Lentin, Primrose; Bourke-Taylor, Helen

2016-02-01

One of the factors known to contribute to a 'good life' following an acquired disability is making connections with others, often achieved through participation in activities outside the home. The majority of outcomes research following SCI has focussed on impairments and activity limitations with less emphasis on participation. This paper reports part of a larger study that explored the experience and meaning of social and community participation following SCI. The research question guiding the part of the study reported in this paper was: What are the facilitators and barriers to social and community participation following acquired SCI? Semi-structured interviews were conducted with 17 adults with traumatically acquired spinal cord injury living in the community. Interviews were audio-recorded, transcribed verbatim and analysed using thematic analysis. Three main themes and 11 subthemes were identified. The main themes were: Resources and environmental accessibility impact social participation; other people influence community engagement; health issues affect social participation. Adequate financial resources and social support (from friends and family, and from peer mentors) were found to assist social participation, while the physical environment, unsupportive social attitudes and mental health issues were identified as barriers to community participation. This study contributes to the evidence base regarding outcomes following SCI. Enabling engagement in meaningful activities in the community must be at the forefront of occupational therapy intervention, both at an individual client level and through advocacy and policy involvement, to improve the quality of life of people with SCI living in the community. © 2015 Occupational Therapy Australia.

Surgical techniques influence local environment of injured spinal cord and cause various grafted cell survival and integration.

PubMed

Hou, Shaoping; Saltos, Tatiana M; Iredia, Idiata W; Tom, Veronica J

2018-01-01

Cellular transplantation to repair a complete spinal cord injury (SCI) is tremendously challenging due to the adverse local milieu for graft survival and growth. Results from cell transplantation studies yield great variability, which may possibly be due to the surgical techniques employed to induce an SCI. In order to delineate the influence of surgery on such inconsistency, we compared lesion morphology and graft survival as well as integration from different lesion methodologies of SCI. Surgical techniques, including a traditional approach cut+microaspiration, and two new approaches, cut alone as well as crush, were employed to produce a complete SCI, respectively. Approximately half of the rats in each group received injury only, whereas the other half received grafts of fetal brainstem cells into the lesion gap. Eight weeks after injury with or without graft, histological analysis showed that the cut+microaspiration surgery resulted in larger lesion cavities and severe fibrotic scars surrounding the cavity, and cellular transplants rarely formed a tissue bridge to penetrate the barrier. In contrast, the majority of cases treated with cut alone or crush exhibited smaller cavities and less scarring; the grafts expanded and blended extensively with the host tissue, which often built continuous tissue bridging the rostral and caudal cords. Scarring and cavitation were significantly reduced when microaspiration was avoided in SCI surgery, facilitating graft/host tissue fusion for signal transmission. The result suggests that microaspiration frequently causes severe scars and cavities, thus impeding graft survival and integration. Copyright © 2017 Elsevier B.V. All rights reserved.

Identifying Criegee Intermediates As Potential Oxidants In The Troposphere

NASA Astrophysics Data System (ADS)

Novelli, A.; Hens, K.; Tatum Ernest, C.; Martinez, M.; Nölscher, A. C.; Sinha, V.; Paasonen, P.; Petäjä, T.; Sipilä, M.; Elste, T.; Plass-Duelmer, C.; Kubistin, D.; Phillips, G. J.; Williams, J.; Vereecken, L.; Lelieveld, J.; Harder, H.

2015-12-01

Criegee intermediates (CI) are formed during the ozonolysis of unsaturated compounds and have been intensively studied in the last few years due to their possible role as oxidants in the troposphere. Stabilised CI (SCI) are now known to react very rapidly, k(298 K) = 10-12 to 10-10 cm3 molecule-1 s-1, with a large number of trace gases (SO2, NO2, organic acids, water dimers). An assessment of their effective oxidative capacity remain challenging as, CI chemistry is complex, it spans a large range of rate coefficients for different SCI conformers reacting with water dimers and trace gases, and in addition, no reliable measurement technique able to detect ambient SCI concentrations is currently available. In this study, we examine the extensive dataset from the HUMPPA-COPEC 2010 and the HOPE 2012 field campaigns, aided by literature data, to estimate the abundance of SCI in the lower troposphere. The budget of SCI is analyzed using four different approaches: 1) based on an observed yet unexplained H2SO4 production; 2) from the measured concentrations of unsaturated volatile organic compounds (VOC); 3) from OH reactivity measurements; 4) from the unexplained production rate of OH. A SCI concentration range between 5 x 103 and 2 x 106 molecule cm-3 is calculated for the two environments. The weighted mean estimate of the SCI concentration over the boreal forest of ~ 5 x 104 molecules cm-3 implies a significant impact on the conversion of SO2 into H2SO4. In addition, we present measurements obtained using our inlet pre-injector laser-induced fluorescence assay by gas expansion technique (IPI-LIF-FAGE) for the above-mentioned campaigns. A recent laboratory study performed with the same instrumental setup showed that the IPI-LIF-FAGE system is sensitive to the detection of the OH formed from unimolecular decomposition of SCI. In order to investigate the applicability of the laboratory findings to the ambient data, measurement of the background OH (OHbg), the signal detected by the IPI-LIF-FAGE after the removal of ambient OH, measured during the two field campaigns are represented in comparison with many other trace gases to assess if the observations in controlled conditions are transferable to ambient conditions.

Bacterial Formation of As(V) and As(III) Ferric Oxyhydroxides in Acid Mine Drainage.

NASA Astrophysics Data System (ADS)

Morin, G.; Juillot, F.; Lebrun, S.; Casiot, C.; Elbaz-Poulichet, F.; Bruneel, O.; Personne, J.; Leblanc, M.; Ildefonse, P.; Calas, G.

2002-12-01

The oxidation of dissolved Fe(II) which is often promoted by acidophilic bacteria in acid mine drainage (AMD) and some hot springs, leads to the precipitation of Fe(III) oxy-hydroxides which incorporate toxic elements within their structure or adsorb them at their surface, thus limiting their mobility. In such complex natural systems, synchrotron-based techniques as X-ray absorption spectroscopy offer the opportunity to monitor surface/solution interactions as well as redox changes affecting the mobility and toxicity of trace elements as arsenic. Spatial and seasonal variations of the (bio-) oxidation of Fe(II) and As(III), and the subsequent precipitation of As-Fe gels, were followed by XANES, XRD, and SEM along the CarnoulŠs AMD (Gard, France). Chemical and mineralogical data collected on sediments, stromatolite, and bioassay samples showed that some indigenous bacteria living in the As-rich CarnoulŠs water ([As] = up to 350 mg.l-1) play an important role in the nature and composition of the solid phases that sequester arsenic at the site. The formation of nano-crystalline and amorphous As(III) ferric oxy-hydroxides has been related to the presence of bacteria able to oxidize Fe(II) but not As(III), which are only present in winter in the upstream area. A rare ferric arsenite sulfate oxy-hydroxide mineral was discovered in this context. Other types of bacteria, occurring in the downstream area whatever the season, are able to catalyze As(III) to As(V) oxidation and, provided that enough Fe(II) oxidizes, promote the formation of amorphous As(V) rich ferric oxy-hydroxides. These bacterially mediated reactions significantly reduce the concentration of dissolved As(III), which is more toxic and mobile than As(V), and might thus be helpful for designing As-removal processes. This work was supported by the French PEVS and ACI Ecologie Quantitative Programs and the PIRAMID EC program. ?Deceased, 26 October 1999 Juillot F., Ildefonse Ph., Morin G., Calas G., De Kersabiec A.M. and Benedetti M. Applied Geochemistry 8, 1031-1048 (1999). Morin G., Lecocq D., Juillot F., Ildefonse Ph., Calas Bull. Soc. Géol. Fr. 173, 281-291 (2002). Morin G., Juillot F., Casiot C., Bruneel O., Personné J-C., Elbaz-Poulichet F., Leblanc M., Ildefonse P. and Calas G. Environ. Sci. Technol (in review.)

Formation of halogenated acetones in the lower troposphere

NASA Astrophysics Data System (ADS)

Sattler, Tobias; Wittmer, Julian; Krause, Torsten; Schöler, Heinz Friedrich; Kamilli, Katharina; Held, Andreas; Zetzsch, Cornelius; Ofner, Johannes; Atlas, Elliot

2015-04-01

Western Australia is a semi-/arid region that is heavily influenced by climate change and agricultural land use. The area is known for its saline lakes with a wide range of hydrogeochemical parameters and consists of ephemeral saline and saline groundwater fed lakes with a pH range from 2.5 to 7.1. In 2012 a novel PTFE-chamber was setup directly on the lakes. The 1.5 m³ cubic chamber was made of UV transparent PTFE foil to permit photochemistry while preventing dilution of the air due to lateral wind transport. This experimental setup allows linking measured data directly to the chemistry of and above the salt lakes. Air samples were taken using stainless steel canisters and measured by GC-MS/ECD. Sediment, crust and water samples were taken for investigation of potential VOC and VOX emissions in the laboratory using GC-MS. Several lakes were investigated and canister samples were taken over the day to see diurnal variations. The first samples were collected at 6 a.m. and from this time every 2 hours a canister was filled with chamber air. Concentrations of chloroacetone up to 15 ppb and of bromoacetone up to 40 ppb in the air samples were detected. The concentrations vary over the day and display their highest values around noon. Soil and water samples showed a variety of highly volatile and semi-volatile VOC/VOX but no halogenated acetones. An abiotic formation of these VOC/VOX seems conclusive due to iron-catalysed reactions below the salt crust [1]. The salt crust is the interface through which VOC/VOX pass from soil/groundwater to the atmosphere where they were photochemically altered. This explains the finding of halo acetones only in the air samples and not in water and soil samples measured in the laboratory. The main forming pathway for these haloacetones is the direct halogenation due to atomic chlorine and bromine above the salt lakes [2]. A minor pathway is the atmospheric degradation of chloropropane and bromopropane [3]. These halopropanes were found in minor concentrations in soil and water samples (maximum of 8.8 ng/g in soil and 0,012 ng/ml in water). [1] Huber et al., 2009, Environ.Sci.Technol., 43 (13), 4934-4939 [2] Wittmer et al., 2014, J. Phys. Chem. A, DOI: 10.1021/jp508006s [3] Burkholder et al., 2002, Geophysical Research Letters, 29 (17)

Recovery of nitrogen and phosphorus from alkaline fermentation liquid of waste activated sludge and application of the fermentation liquid to promote biological municipal wastewater treatment.

PubMed

Tong, Juan; Chen, Yinguang

2009-07-01

In previous publications we reported that by controlling the pH at 10.0 the accumulation of short-chain fatty acids (SCFA) during waste activated sludge (WAS) fermentation was remarkably improved [Yuan, H., Chen, Y., Zhang, H., Jiang, S., Zhou, Q., Gu, G., 2006. Improved bioproduction of short-chain fatty acids (SCFAs) from excess sludge under alkaline conditions. Environ. Sci. Technol. 40, 2025-2029], but significant ammonium nitrogen (NH(4)-N) and soluble ortho-phosphorus (SOP) were released [Chen, Y., Jiang, S., Yuan, H., Zhou, Q., Gu, G., 2007. Hydrolysis and acidification of waste activated sludge at different pHs. Water Res. 41, 683-689]. This paper investigated the simultaneous recovery of NH(4)-N and SOP from WAS alkaline fermentation liquid and the application of the fermentation liquid as an additional carbon source for municipal wastewater biological nitrogen and phosphorus removal. The central composite design (CCD) of the response surface methodology (RSM) was employed to optimize and model the simultaneous NH(4)-N and SOP recovery from WAS alkaline fermentation liquid. Under the optimum conditions, the predicted and experimental recovery efficiency was respectively 73.4 and 75.7% with NH(4)-N, and 82.0 and 83.2% with SOP, which suggested that the developed models described the experiments well. After NH(4)-N and SOP recovery, the alkaline fermentation liquid was added to municipal wastewater, and the influence of volume ratio of fermentation liquid to municipal wastewater (FL/MW) on biological nitrogen and phosphorus removal was investigated. The addition of fermentation liquid didn't significantly affect nitrification. Both SOP and total nitrogen (TN) removal were increased with fermentation liquid, but there was no significant increase at FL/MW greater than 1/35. Compared to the blank test, the removal efficiency of SOP and TN at FL/MW=1/35 was improved from 44.0 to 92.9%, and 63.3 to 83.2%, respectively. The enhancement of phosphorus and nitrogen removal was mainly attributed to the increase of influent SCFA, or rather, the increase of intracellular polyhydroxyalkanoates (PHA) which served as the carbon and energy sources for denitrification and phosphorus uptake. The addition of alkaline fermentation liquid to municipal wastewater, however, increased the effluent COD, which was caused mainly by the increase of influent humic acid, not protein or carbohydrate.

Investigating Changes in Iron Solubility and Isotopic Composition of Mineral Dust and Industrial Ash during Simulated Atmospheric Processing

NASA Astrophysics Data System (ADS)

Maters, E. C.; Flament, P.; de Jong, J.; Mattielli, N. D. C.; Deboudt, K.

2017-12-01

Iron (Fe) is a key element in ocean biogeochemistry and hence the carbon cycle. Its low concentration in seawater limits primary production in >30% of the surface ocean, and thus strong interest lies in constraining Fe inputs to the ocean on different spatial and temporal scales. During Earth's past, large fluctuations in atmospheric deposition fluxes of continental particles including mineral dust and volcanic ash to the ocean may have played a role in climate change events. At present, anthropogenic particles from metal working, biomass burning, and fossil fuel combustion are increasingly recognised to deliver Fe to the ocean as well. To assess the relative importance of these particulate Fe sources, knowledge of their deposition flux (overall dominated by natural dusts) and their Fe solubility (a proxy for Fe bioavailability, and typically higher in anthropogenic materials) is needed, although large uncertainties remain in these parameters. A potential tool for tracing atmospheric inputs to the ocean is the Fe isotope composition (δ56Fe), previously reported to be distinct for natural versus anthropogenic particles. However, it remains unknown if and how the δ56Fe is influenced by various physicochemical processes (e.g. acidification, photochemistry) shown to enhance Fe solubility in airborne particles. Iron isotopic fractionation has been observed during ligand-controlled and photo-reductive dissolution of goethite at low pH,[1] and similar effects may apply to more complex materials during atmospheric transport. Specifically, isotopic enrichment in partially dissolved particles may result from initial preferential release of 54Fe over 56Fe from the solid surface. To test these hypotheses, we subjected natural and anthropogenic specimens, including mineral dust from the Sahara desert and industrial ash from an Fe-Mn alloy factory, to simulated atmospheric processing in pH 2 solution in the presence/absence of oxalic acid and solar radiation. The Fe solubility and δ56Fe/IRMM-014 values of the solid samples were measured to determine the extents of fractionation relative to unprocessed particles. The results of these experiments and the implications for tracing atmospheric Fe inputs to the ocean will be presented. [1] Wiederhold, J. G. et. al. (2006) Environ. Sci. Technol., 40, 3787-3793.

An SOA model for toluene oxidation in the presence of inorganic aerosols.

PubMed

Cao, Gang; Jang, Myoseon

2010-01-15

A predictive model for secondary organic aerosol (SOA) formation including both partitioning and heterogeneous reactions is explored for the SOA produced from the oxidation of toluene in the presence of inorganic seed aerosols. The predictive SOA model comprises the explicit gas-phase chemistry of toluene, gas-particle partitioning, and heterogeneous chemistry. The resulting products from the explicit gas phase chemistry are lumped into several classes of chemical species based on their vapor pressure and reactivity for heterogeneous reactions. Both the gas-particle partitioning coefficient and the heterogeneous reaction rate constant of each lumped gas-phase product are theoretically determined using group contribution and molecular structure-reactivity. In the SOA model, the predictive SOA mass is decoupled into partitioning (OM(P)) and heterogeneous aerosol production (OM(H)). OM(P) is estimated from the SOA partitioning model developed by Schell et al. (J. Geophys. Res. 2001, 106, 28275-28293 ) that has been used in a regional air quality model (CMAQ 4.7). OM(H) is predicted from the heterogeneous SOA model developed by Jang et al. (Environ. Sci. Technol. 2006, 40, 3013-3022 ). The SOA model is evaluated using a number of the experimental SOA data that are generated in a 2 m(3) indoor Teflon film chamber under various experimental conditions (e.g., humidity, inorganic seed compositions, NO(x) concentrations). The SOA model reasonably predicts not only the gas-phase chemistry, such as the ozone formation, the conversion of NO to NO(2), and the toluene decay, but also the SOA production. The model predicted that the OM(H) fraction of the total toluene SOA mass increases as NO(x) concentrations decrease: 0.73-0.83 at low NO(x) levels and 0.17-0.47 at middle and high NO(x) levels for SOA experiments with high initial toluene concentrations. Our study also finds a significant increase in the OM(H) mass fraction in the SOA generated with low initial toluene concentrations, compared to those with high initial toluene concentrations. On average, more than a 1-fold increase in OM(H) fraction is observed when the comparison is made between SOA experiments with 40 ppb toluene to those with 630 ppb toluene. Such an observation implies that heterogeneous reactions of the second-generation products of toluene oxidation can contribute considerably to the total SOA mass under atmospheric relevant conditions.

Consideration of HOMs in α- and β-pinene SOA model

NASA Astrophysics Data System (ADS)

Gatzsche, Kathrin; Iinuma, Yoshiteru; Mutzel, Anke; Berndt, Torsten; Wolke, Ralf

2016-04-01

Secondary organic aerosol (SOA) is the major burden of the atmospheric organic particulate matter with 140 - 910 TgC yr-1 (Hallquist et al., 2009). SOA particles are formed via the oxidation of volatile organic carbons (VOCs), where the volatility of the VOCs is lowered due to the increase in their functionalization as well as their binding ability. Therefore, gaseous compounds can either nucleate to form new particles or condense on existing particles. The framework of SOA formation under natural conditions is very complex, because there are a multitude of gas-phase precursors, atmospheric degradation processes and products after oxidation. A lacking understanding about chemical and physical processes associated with SOA formation makes modeling of SOA processes difficult, leading to discrepancy between measured and modeled global SOA burdens. The present study utilizes a parcel model SPACCIM (SPectral Aerosol Cloud Chemistry Interaction Model, Wolke et al., 2005) that couples a multiphase chemical model with a microphysical model. For SOA modeling a further development of SPACCIM was necessary. Therefore, two components are added (i) a gas-phase chemistry mechanism for the VOC oxidation and (ii) a partitioning approach for the gas-to-particle phase transfer. An aggregated gas-phase chemistry mechanism for α- and β-pinene was adapted from Chen and Griffin (2005). For the phase transfer an absorptive partitioning approach (Pankow, 1994) and a kinetic approach (Zaveri et al., 2014) are implemented. Whereby the kinetic approach serves some advantages. The organic aerosol can be resolved in different size sections, whereby the particle radius is involved in the partitioning equations. The phase state of the organic material and the reactivity of the organic compounds in the particle-phase directly influence the modeled SOA yields. Recently, highly oxidized multifunctional organic compounds (HOMs) were found in the gas phase from lab and field studies. They are also known as extremely low-volatile organic compounds (ELVOCs) (Ehn et al. 2014). The importance of HOMs for the early aerosol growth makes them indispensable in SOA modeling. Thus, we included HOMs in our model framework. The measurements from the institute's own smog chamber LEAK are used as a base for model evaluation and process analysis, especially since HOMs were lately identified from LEAK data (Mutzel et al., 2015). The presentation will provide a sensitivity study for the kinetic approach as well as a comparison of measured and modeled SOA yields. References: Ehn, M., Thornton, J. A., Kleist, E. et al. (2014) Nature, 506, 476 - 479 Hallquist, M., Wenger, J. C., Baltensperger, U., et al. (2009) Atmos. Chem. Phys., 9, 5155 - 5236 Mutzel, A., Poulain, L., Berndt, T. et al. (2015) Environ. Sci. Technol., 49, 7754 - 7761 Pankow, J. F. (1994) Atmos. Environ., 28, 2, 189 - 193 Wolke, R., Sehili, A. M., Simmel, M., Knoth, O., Tilgner, A. and Herrmann, H. (2005) Atmos. Environ., 39, 4375 - 4388 Zaveri, R. A., Easter, R. C., Shilling J. E. and Seinfeld, J. H. (2014) Atmos. Chem. Phys., 14, 5153 - 5181

Interaction of ribonucleotides with oxide and silicate minerals under varying environmental conditions

NASA Astrophysics Data System (ADS)

Feuillie, C.; Sverjensky, D. A.; Hazen, R. M.

2013-12-01

Large quantities of nucleic acids are found in natural environments, released after the death of an organism and subsequent cell lysis [1]. Nucleic acids are known to adsorb on mineral surfaces [2, 3, 4], which protect them from degradation, whether enzymatic [5, 6] or UV-mediated [7]. It may then contribute to the extracellular genetic pool available in soils to microorganisms for horizontal gene transfers [8]. In order to better understand the behaviour of extracellular nucleic acids in soils, we have investigated the interactions between nucleotides, 5'-GMP, 5'-CMP, 5'-AMP and 5'-UMP, and α-alumina as a model compound for Al in six-fold coordination in soil minerals. We carried out batch adsorption experiments over a wide range of pH, ionic strength and surface loading. Alumina adsorbs high amounts of nucleotides > 2 μmol/m2. In similar environmental conditions, swelling clays such as nontronite and montmorillonite adsorb less than 0.1 μmol/m2 if the total surface area is taken under consideration. However, if only the edges of clay particles are considered, the amount of nucleotides adsorbed reaches values between 1.2 and 2 μmol/m2 [9], similar to the alumina and consistent with ';oxide-like' surface sites on the edges of the clay particles. Surface complexation modeling enabled us to predict the speciation of the surface species on the alumina, as well as the stoichiometry and thermodynamic equilibrium constants for the adsorption of nucleotides. We used the extended triple-layer model (ETLM), that takes into account the electrical work linked to the desorption of chemisorbed water molecules during the formation of inner-sphere complexes. Two surface species are thought to form on the surface of corundum: a monodentate inner-sphere complex, dominant at pH < 7.5, and a bidentate outer-sphere complex, dominant at higher pH. Both complexes involve interactions between the negatively charged phosphate group and the positively charged surface of alumina. Our results provide a better understanding of how nucleic acids attach to mineral surfaces under varying environmental conditions in soil environments. Moreover, the predicted configuration of nucleotide surface species, bound via the phosphate group, could have implications for the abiotic formation and concentration of nucleic acids in the context of the origin of life. References : [1] Lorenz and Wackernagel (1987), Applied and environmental microbial., 2948-2952 [2] Ferris (2005), Reviews in mineralogy & geochemistry 59, 187-210 [3] Cleaves H.J. et al. (2011), Chemosphere 83, 1560-1567 [4] Arora & Kamaluddin (2009), Astrobiology 9, 165-171 [5] Cai et al. (2006), Environ. Sci. Technol. 40 (9), 2971-2976 [6] Franchi and Gallori (2005),Gene 346, 205-214 [7] Scappini et al. (2004), International Journal of Astrobiology 3(1), 17-19 [8] Levy-Booth et al. (2007), Soil Biol. Biochem. 39, 2977-2991. [9] Feuillie et al. (2013), Geochimica et Cosmochimica Acta (in press)

Transforming NAD 27 and NAD 83 positions : making legacy mapping and surveys GPS compatible.

DOT National Transportation Integrated Search

2015-06-01

The Connecticut Department of Transportation (CTDOT) and the University of Connecticut are creating a real-time network (RTN) to make real-time surveying widely available in Connecticut. This RTN uses global navigation satellite system (GNSS) technol...

Preface: SciDAC 2007

NASA Astrophysics Data System (ADS)

Keyes, David E.

2007-09-01

It takes a village to perform a petascale computation—domain scientists, applied mathematicians, computer scientists, computer system vendors, program managers, and support staff—and the village was assembled during 24-28 June 2007 in Boston's Westin Copley Place for the third annual Scientific Discovery through Advanced Computing (SciDAC) 2007 Conference. Over 300 registered participants networked around 76 posters, focused on achievements and challenges in 36 plenary talks, and brainstormed in two panels. In addition, with an eye to spreading the vision for simulation at the petascale and to growing the workforce, 115 participants—mostly doctoral students and post-docs complementary to the conferees—were gathered on 29 June 2007 in classrooms of the Massachusetts Institute of Technology for a full day of tutorials on the use of SciDAC software. Eleven SciDAC-sponsored research groups presented their software at an introductory level, in both lecture and hands-on formats that included live runs on a local BlueGene/L. Computation has always been about garnering insight into the behavior of systems too complex to explore satisfactorily by theoretical means alone. Today, however, computation is about much more: scientists and decision makers expect quantitatively reliable predictions from simulations ranging in scale from that of the Earth's climate, down to quarks, and out to colliding black holes. Predictive simulation lies at the heart of policy choices in energy and environment affecting billions of lives and expenditures of trillions of dollars. It is also at the heart of scientific debates on the nature of matter and the origin of the universe. The petascale is barely adequate for such demands and we are barely established at the levels of resolution and throughput that this new scale of computation affords. However, no scientific agenda worldwide is pushing the petascale frontier on all its fronts as vigorously as SciDAC. The breadth of this conference archive reflects the philosophy of the SciDAC program, which was introduced as a collaboration of all of the program offices in the Office of Science of the U.S. Department of Energy (DOE) in Fall 2001 and was renewed for a second period of five years in Fall 2006, with additional support in certain areas from the DOE's National Nuclear Security Administration (NNSA) and the U.S. National Science Foundation (NSF). All of the projects in the SciDAC portfolio were represented at the conference and most are captured in this volume. In addition, the Organizing Committee incorporated into the technical program a number of computational science highlights from outside of SciDAC, and, indeed, from outside of the United States. As implied by the title, scientific discovery is the driving deliverable of the SciDAC program, spanning the full range of the DOE Office of Science: accelerator design, astrophysics, chemistry and materials science, climate science, combustion, life science, nuclear physics, plasma physics, and subsurface physics. As articulated in the eponymous report that launched SciDAC, the computational challenges of these diverse areas are remarkably common. Each is profoundly multiscale in space and time and therefore continues to benefit at any margin from access to the largest and fastest computers available. Optimality of representation and execution requires adaptive, scalable mathematical algorithms in both continuous (geometrically complex domain) and discrete (mesh and graph) aspects. Programmability and performance optimality require software environments that both manage the intricate details of the underlying hardware and abstract them for scientific users. Running effectively on remote specialized hardware requires transparent workflow systems. Comprehending the petascale data sets generated in such simulations requires automated tools for data exploration and visualization. Archiving and sharing access to this data within the inevitably distributed community of leading scientists requires networked collaborative environments. Each of these elements is a research and development project in its own right. SciDAC does not replace theoretical programs oriented towards long-term basic research, but harvests them for contemporary, complementary state-of-the-art computational campaigns. By clustering researchers from applications and enabling technologies into coordinated, mission-driven projects, SciDAC accomplishes two ends with remarkable effectiveness: (1) it enriches the scientific perspective of both applications and enabling communities through mutual interaction and (2) it leverages between applications solutions and effort encapsulated in software. Though SciDAC is unique, its objective of multiscale science at extreme computational scale is shared and approached through different programmatic mechanisms, notably NNSA's ASC program, NSF's Cyberinfrastructure program, and DoD's CREATE program in the U.S., and RIKEN's computational simulation programs in Japan. Representatives of each of these programs were given the podium at SciDAC 2007 and communication occurred that will be valuable towards the ends of complementarity, leverage, and promulgation of best practices. The 2007 conference was graced with additional welcome program announcements. Michael Strayer announced a new program of postdoctoral research fellowships in the enabling technologies. (The computer science post-docs will be named after the late Professor Ken Kennedy, who briefly led the SciDAC project Center for Scalable Application Development Software (CScADS) until his untimely death in February 2007.) IBM announced its petascale BlueGene/P system on June 26. Meanwhile, at ISC07 in Dresden, the semi-annual posting of a revised Top 500 list on June 27 showed several new Top 10 systems accessible to various SciDAC participants. While SciDAC is dominated in 2007 by the classical scientific pursuit of understanding through reduction to components and isolation of causes and effects, simulation at scale is beginning to offer something even more tantalizing: synthesis and integration of multiple interacting phenomena in complex systems. Indeed, the design-oriented elements of SciDAC, such as accelerator and tokamak modeling, area already emphasizing multiphysics coupling, and climate science has been doing so for years in the coupling of models of the ocean, atmosphere, ice, and land. In one of the panels at SciDAC 2007, leaders of a three-stage `progressive workshop' on exascale simulation for energy and environment (E3), considered prospects for whole-system modeling in a variety of scientific areas within the domain of DOE related to energy, environmental, and global security. Computer vendors were invited to comment on the prospects for delivering exascale computing systems in another panel. The daunting nature of this challenge is summarized with the observation that the peak processing power of the entire Top 500 list of June 2007 is only 0.0052 exaflop/s. It takes the combined power of most of the computers on the internet today worldwide to reach 1 exaflop/s or 1018 floating point operations per second. The program of SciDAC 2007 followed a template honed by its predecessor meetings in San Francisco in 2005 and Denver in 2006. The Boston venue permitted outreach to a number of universities in the immediate region and throughout southern New England, including SciDAC campuses of Boston University, Harvard, and MIT, and a dozen others including most of the Ivy League. Altogether 55 universities, 20 laboratories, 14 private companies, 5 agencies, and 4 countries were represented among the conference and tutorial workshop participants. Approximately 47% of the conference participants were from government laboratories, 37% from universities, 9% from federal program offices, and 7% from industry. Keys to the success of SciDAC 2007 were the informal poster receptions, coffee breaks, working breakfasts and lunches, and even the `Right-brain Night' featuring artistic statements, both reverent and irreverent, by computational scientists, inspired by their work. The organizers thank the sponsors for their generosity in attracting participants to these informal occasions with sumptuous snacks and beverages: AMD, Cray, DataDirect, IBM, SGI, SiCortex, and the Institute of Physics. A conference as logistically complex as SciDAC 2007 cannot possibly and should not be executed primarily by the scientists, themselves. It is a great pleasure to acknowledge the many talented staff that contributed to a productive time for all participants and nearperfect adherence to schedule. Chief among them is Betsy Riley, currently detailed from ORNL to the program office in Germantown, with degrees in mathematics and computer science, but a passion for organizing interdisciplinary scientific programs. Betsy staffed the organizing committee during the year of telecon meetings leading up to the conference and masterminded sponsorship, invitations, and the compilation of the proceedings. Assisting her from ORNL in managing the program were Daniel Pack, Angela Beach, and Angela Fincher. Cynthia Latham of ORNL performed admirably in website and graphic design for all aspects of the online and printed materials of the meeting. John Bui, John Smith, and Missy Smith of ORNL ran their customary tight ship with respect to audio-visual execution and capture, assisted by Eric Ecklund and Keith Quinn of the Westin. Pamelia Nixon-Hartje of Ambassador Services was personally invaluable in getting the most out of the hotel and its staff. We thank Jeff Nichols of ORNL for managing the primary subcontract for the meeting. The SciDAC tutorial program was a joint effort of Professor John Negele of MIT, David Skinner, PI of the SciDAC Outreach Center, and the SciDAC 2007 Chair. Sponsorship from the Outreach Center in the form of travel scholarships for students, and of the local area SciDAC university delegation of BU, Harvard, and MIT for food and facilities is gratefully acknowledged. Of course, the archival success of a scientific meeting rests with the willingness of the presenters to make the extra effort to package their field-leading science in a form suitable for interaction with colleagues from other disciplines rather than fellow specialists. This goal, oft-stated in the run up to the meeting, was achieved to an admirable degree, both in the live presentations and in these proceedings. This effort is its own reward, since it leads to enhanced communication and accelerated scientific progress. Our greatest thanks are reserved for Michael Strayer, Associate Director for OASCR and the Director of SciDAC, for envisioning this celebratory meeting three years ago, and sustaining it with his own enthusiasm, in order to provide a highly visible manifestation of the fruits of SciDAC. He and the other Office of Science program managers in attendance and working in Washington, DC to communicate the opportunities afforded by SciDAC deserve the gratitude of a new virtual scientific village created and cemented under the vision of scientific discovery through advanced computing. David E Keyes Fu Foundation Professor of Applied Mathematics

SciBox, an end-to-end automated science planning and commanding system

NASA Astrophysics Data System (ADS)

Choo, Teck H.; Murchie, Scott L.; Bedini, Peter D.; Steele, R. Josh; Skura, Joseph P.; Nguyen, Lillian; Nair, Hari; Lucks, Michael; Berman, Alice F.; McGovern, James A.; Turner, F. Scott

2014-01-01

SciBox is a new technology for planning and commanding science operations for Earth-orbital and planetary space missions. It has been incrementally developed since 2001 and demonstrated on several spaceflight projects. The technology has matured to the point that it is now being used to plan and command all orbital science operations for the MErcury Surface, Space ENvironment, GEochemistry, and Ranging (MESSENGER) mission to Mercury. SciBox encompasses the derivation of observing sequences from science objectives, the scheduling of those sequences, the generation of spacecraft and instrument commands, and the validation of those commands prior to uploading to the spacecraft. Although the process is automated, science and observing requirements are incorporated at each step by a series of rules and parameters to optimize observing opportunities, which are tested and validated through simulation and review. Except for limited special operations and tests, there is no manual scheduling of observations or construction of command sequences. SciBox reduces the lead time for operations planning by shortening the time-consuming coordination process, reduces cost by automating the labor-intensive processes of human-in-the-loop adjudication of observing priorities, reduces operations risk by systematically checking constraints, and maximizes science return by fully evaluating the trade space of observing opportunities to meet MESSENGER science priorities within spacecraft recorder, downlink, scheduling, and orbital-geometry constraints.

An ecosystem-scale perspective of the net land methanol flux: synthesis of micrometeorological flux measurements

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wohlfahrt, G.; Amelynck, C.; Ammann, Christof

2015-07-09

We present field observations made in June 2011 downwind of Dallas-Fort Worth, TX, and evaluate the role of stabilized Criegee radicals (sCIs) in gaseous sulfuric acid (H2SO4) production. Zero-dimensional model calculations show that sCI from BVOCs composed the majority of the sCIs. The main uncertainty associated with an evaluation of H2SO4 production from the sCI reaction channel is the lack of experimentally determined reaction rates for sCIs formed from isoprene ozonolysis with SO2. In general, the maximum of H2SO4 production from the sCI channel is found in the late afternoon as ozone increases towards the late afternoon. The sCI channel,more » however, contributes minor H2SO4 production compared with the conventional OH channel. Finally, The production and the loss rates of H2SO4 are compared. The application of the recommended mass accommodation coefficient causes significant overestimation of H2SO4 loss rates compared with H2SO4 production rates. On the other hand, the application of a lower experimental value for the mass accommodation coefficient provides good agreement between the loss and production rates of H2SO4. The results suggest that the recommended coefficient for the H2O surface may not be suitable for this relatively dry environment.« less

Determination of the Threshold of Gravity for the Susceptibility to Kinetosis in Fish - a Centrifuge Experiment in the ZARM Drop-Tower employing gradually reduced Gravity

NASA Astrophysics Data System (ADS)

Anken, R.; Hilbig, R.

In the course of earlier experiments at diminished gravity conditions we have successfully used larval cichlid fish Oreochromis mossambicus as a vertebrate model system in investigating the basic cause of susceptibility to motion sickness kinetosis It was observed that most animals of a given batch reveal kinetoses i e performing looping responses LR or spinning movements SM at high quality microgravity 10-6g ZARM drop-tower whereas comparatively few individuals swim kinetotically at low quality microgravity LQM 0 03-0 05g during parabolic aircraft flights Anken and Hilbig Microgravity Sci Technol 15 52-57 2004 In order to gain further insights into a possible threshold of gravity for inducing motion sickness animals were subjected to drop-tower flights within a centrifuge The levels of gravity applied ranged from 0 009g until 0 3g The lowest level of gravity under which few normally swimming fish were observed ranged around 0 015g Since this is a very low level of gravity the normally swimming fish have to be considered to be either extremely sensitive to any force of gravity in order to use it as a cue for postural control or they use cues other than the residual gravity for maintaining equilibrium Most of the remaining kinetotically swimming animals showed LR whereas few exhibited SM With increasing gravity the ratio of normally swimming and spinning specimens increased accompanied by a decrease in the number of looping larvae Regarding the ratio a shift from LR to SM took place at around 0 02g At 0 3g all animals behaved

Analytical investigation of microwave resonances of a curling probe for low and high-pressure plasma diagnostics

NASA Astrophysics Data System (ADS)

Arshadi, Ali; Brinkmann, Ralf Peter

2017-01-01

The concept of ‘active plasma resonance spectroscopy’ (APRS) has attracted greater interest in recent years as an established plasma diagnostic technique. The APRS describes a class of related methods utilizing the intrinsic ability of plasma to resonate at or near the electron plasma frequency {ω\\text{pe}} . The Curling probe (CP) as a novel realization of the APRS idea, is a miniaturized spiral slot embedded flatly in the chamber wall. Consequently, a plasma diagnostic technique with minimum disturbance and without metal contamination can be developed. To measure the plasma parameters the CP is fed with a weak frequency-swept signal from the exterior of the plasma chamber by a network analyzer which also records the response of the plasma versus the frequency. The resonance behavior is strongly dependent on the electron density and the gas pressure. The CP has also the advantage of resonating at a frequency greater than {ω\\text{pe}} which is dependent on the spiral’s length. The double resonance characteristic gives the CP the ability to be applied in varying plasma regimes. Assuming that the spiralization does not have a considerable effect on the resonances, a ‘straightened’ infinite length CP has recently been investigated (Arshadi and Brinkmann 2016 Plasma Sources Sci. Technol. 25 045014) to obtain the surface wave resonances. This work generalizes the approach and models the CP by a rectangular slot-type resonator located between plasma and quartz. Cold plasma theory and Maxwell’s equations are utilized to compute the electromagnetic fields propagating into the plasma by the diffraction of an incident plane wave at the slot. A mathematical model is employed and both kinds of resonances are derived. The analytical study of this paper shows good agreement with the numerical results of the probe inventors.

Fast-ion transport in qmin>2, high- β steady-state scenarios on DIII-D

DOE PAGES

Holcomb, C. T.; Heidbrink, W. W.; Ferron, J. R.; ...

2015-05-22

The results from experiments on DIII-D [J. L. Luxon, Fusion Sci. Technol. 48, 828 (2005)] aimed at developing high β steady-state operating scenarios with high-qminqmin confirm that fast-ion transport is a critical issue for advanced tokamak development using neutral beam injection current drive. In DIII-D, greater than 11 MW of neutral beam heating power is applied with the intent of maximizing β N and the noninductive current drive. However, in scenarios with q min>2 that target the typical range of q 95= 5–7 used in next-step steady-state reactor models, Alfvén eigenmodes cause greater fast-ion transport than classical models predict. Thismore » enhanced transport reduces the absorbed neutral beam heating power and current drive and limits the achievable β N. Conversely similar plasmas except with q min just above 1 have approximately classical fast-ion transport. Experiments that take q min>3 plasmas to higher β P with q 95= 11–12 for testing long pulse operation exhibit regimes of better than expected thermal confinement. Compared to the standard high-q min scenario, the high β P cases have shorter slowing-down time and lower ∇β fast, and this reduces the drive for Alfvénic modes, yielding nearly classical fast-ion transport, high values of normalized confinement, β N, and noninductive current fraction. These results suggest DIII-D might obtain better performance in lower-q 95, high-q min plasmas using broader neutral beam heating profiles and increased direct electron heating power to lower the drive for Alfvén eigenmodes.« less

Development of diagnostic and manipulation systems for space-charge dominated electron beams and confined electron plasmas in ELTRAP

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rome, M.; Cavaliere, F.; Maero, G.

2013-03-19

Modifications have been implemented in the Penning-Malmberg device ELTRAP aimed at performing studies on the dynamics of space-charge dominated nanosecond electron bunches traveling along the magnetic field. In particular, a Thomson backscattering apparatus has been developed where an infrared (IR) laser pulse collides with the bunched electron beam. The frequency-shifted backscattered radiation, acquired by means of a photomultiplier (PMT), can be exploited to evaluate information on energy, energy spread and density of the bunch. The achievable sensitivity of the diagnostics has been estimated, and valuable information on the main parameters affecting the signal-to-noise (S/N) ratio has been obtained [B. Paroli,more » F. Cavaliere, M. Cavenago, F. De Luca, M. Ikram, G. Maero, C. Marini, R. Pozzoli, and M. Rome, JINST 7, P01008 (2012)]. A series of upgrades are under way, aimed at increasing the S/N ratio through the use of a new laser for the electron source, the insertion of a stray light shield, and the optimization of the detection electronics. Moreover, electromagnetic simulations relevant to the design and implementation of a microwave heating system are presented. The generation of an electron plasma in ELTRAP by means of a low-power radio frequency (RF) drive in the MHz range applied on one of the trap electrodes and under ultra-high vacuum (UHV) conditions has previously been demonstrated [B. Paroli, F. De Luca, G. Maero, F. Pozzoli, and M. Rome, Plasma Sources Sci. Technol. 19, 045013 (2010)]. The new heating system will allow the extension of the RF studies to the GHz range and in particular the production of a more energetic electron plasma via cyclotron resonant excitation.« less

Dynamics of δ-dopant redistribution during heterostructure growth

NASA Astrophysics Data System (ADS)

Pankratov, E. L.

2007-06-01

It has recently been shown that growth of a multilayer structure with one or more delta-layers at high temperature leads to spreading and asymmetrization of the dopant distribution [see, for example, E.F.J. Schubert, Vac. Sci. Technol. A. 8, 2980 (1990), A.M. Nazmul, S. Sugahara, M. Tanaka, J. Crystal Growth 251, 303 (2003); R.C. Newman, M.J. Ashwin, M.R. Fahy, L. Hart, S.N. Holmes, C. Roberts, X. Zhang, Phys. Rev. B 54, 8769 (1996); E.F. Schubert, J.M. Kuo, R.F. Kopf, H.S. Luftman, L.C. Hopkins, N.J. Sauer, J. Appl. Phys. 67, 1969 (1990); P.M. Zagwijn, J.F. van der Veen, E. Vlieg, A.H. Reader, D.J. Gravesteijn, J. Appl. Phys. 78, 4933 (1995); W.S. Hobson, S.J. Pearton, E.F. Schubert, G. Cabaniss, Appl. Phys. Lett. 55, 1546 (1989); Delta Doping of Semiconductors, edited by E.F. Schubert (Cambridge University Press, Cambridge, 1996); Yu.N. Drozdov, N.B. Baidus', B.N. Zvonkov, M.N. Drozdov, O.I. Khrykin, V.I. Shashkin, Semiconductors 37, 194 (2003); E. Skuras, A.R. Long, B. Vogele, M.C. Holland, C.R. Stanley, E.A. Johnson, M. van der Burgt, H. Yaguchi, J. Singleton, Phys. Rev. B 59, 10712 (1999); G. Li, C. Jagadish, Solid-State Electronics 41, 1207 (1997)]. In this work analytical and numerical analysis of dopant dynamics in a delta-doped area of a multilayer structure has been accomplished using Fick's second law. Some reasons for asymmetrization of a delta-dopant distribution are illustrated. The spreading of a delta-layer has been estimated using example materials of a multilayer structure, a delta-layer and an overlayer.

Multi-channel transport experiments at Alcator C-Mod and comparison with gyrokinetic simulations

DOE Office of Scientific and Technical Information (OSTI.GOV)

White, A. E.; Howard, N. T.; Greenwald, M.

2013-05-15

Multi-channel transport experiments have been conducted in auxiliary heated (Ion Cyclotron Range of Frequencies) L-mode plasmas at Alcator C-Mod [Marmar and Alcator C-Mod Group, Fusion Sci. Technol. 51(3), 3261 (2007)]. These plasmas provide good diagnostic coverage for measurements of kinetic profiles, impurity transport, and turbulence (electron temperature and density fluctuations). In the experiments, a steady sawtoothing L-mode plasma with 1.2 MW of on-axis RF heating is established and density is scanned by 20%. Measured rotation profiles change from peaked to hollow in shape as density is increased, but electron density and impurity profiles remain peaked. Ion or electron heat fluxesmore » from the two plasmas are the same. The experimental results are compared directly to nonlinear gyrokinetic theory using synthetic diagnostics and the code GYRO [Candy and Waltz, J. Comput. Phys. 186, 545 (2003)]. We find good agreement with experimental ion heat flux, impurity particle transport, and trends in the fluctuation level ratio (T(tilde sign){sub e}/T{sub e})/(ñ{sub e}/n{sub e}), but underprediction of electron heat flux. We find that changes in momentum transport (rotation profiles changing from peaked to hollow) do not correlate with changes in particle transport, and also do not correlate with changes in linear mode dominance, e.g., Ion Temperature Gradient versus Trapped Electron Mode. The new C-Mod results suggest that the drives for momentum transport differ from drives for heat and particle transport. The experimental results are inconsistent with present quasilinear models, and the strong sensitivity of core rotation to density remains unexplained.« less

Common y-intercept and single compound regressions of gas-particle partitioning data vs 1/T

NASA Astrophysics Data System (ADS)

Pankow, James F.

Confidence intervals are placed around the log Kp vs 1/ T correlation equations obtained using simple linear regressions (SLR) with the gas-particle partitioning data set of Yamasaki et al. [(1982) Env. Sci. Technol.16, 189-194]. The compounds and groups of compounds studied include the polycylic aromatic hydrocarbons phenanthrene + anthracene, me-phenanthrene + me-anthracene, fluoranthene, pyrene, benzo[ a]fluorene + benzo[ b]fluorene, chrysene + benz[ a]anthracene + triphenylene, benzo[ b]fluoranthene + benzo[ k]fluoranthene, and benzo[ a]pyrene + benzo[ e]pyrene (note: me = methyl). For any given compound, at equilibrium, the partition coefficient Kp equals ( F/ TSP)/ A where F is the particulate-matter associated concentration (ng m -3), A is the gas-phase concentration (ng m -3), and TSP is the concentration of particulate matter (μg m -3). At temperatures more than 10°C from the mean sampling temperature of 17°C, the confidence intervals are quite wide. Since theory predicts that similar compounds sorbing on the same particulate matter should possess very similar y-intercepts, the data set was also fitted using a special common y-intercept regression (CYIR). For most of the compounds, the CYIR equations fell inside of the SLR 95% confidence intervals. The CYIR y-intercept value is -18.48, and is reasonably close to the type of value that can be predicted for PAH compounds. The set of CYIR regression equations is probably more reliable than the set of SLR equations. For example, the CYIR-derived desorption enthalpies are much more highly correlated with vaporization enthalpies than are the SLR-derived desorption enthalpies. It is recommended that the CYIR approach be considered whenever analysing temperature-dependent gas-particle partitioning data.

Enhanced circular photogalvanic effect in HgTe quantum wells in the heavily inverted regime

NASA Astrophysics Data System (ADS)

Li, Jun; Yang, Wen; Liu, Jiang-Tao; Huang, Wei; Li, Cheng; Chen, Song-Yan

2017-01-01

HgTe-based quantum wells (QWs) possess very strong spin-orbit interaction (SOI) and have become an ideal platform for the study of fundamental SOI-dependent phenomena and the topological insulator phase. Circular photogalvanic effect (CPGE) in HgTe QWs is of great interest because it provides an effective optical access to probe the spin-related information of HgTe systems. However, the complex band structure and large spin splitting of HgTe QWs makes it inadequate to analyze the experimental results of CPGE in HgTe QWs [B. Wittmann et al., Semicond. Sci. Technol. 25, 095005 (2010), 10.1088/0268-1242/25/9/095005] with reduced band models. Here, based on the realistic eight-band k .p Hamiltonian and combined with the density-matrix formalism, we present a detailed theoretical investigation of CPGE in (001)-oriented Hg0.3Cd0.7Te /HgTe /Hg0.3Cd0.7Te QWs. We find the CPGE currents in HgTe QWs in the heavily inverted regime are significantly enhanced due to the strong distortion of band dispersion at a certain range of the energy spectrum. This enhancement effect could offer an experimental certificate that the HgTe QW is in the heavily inverted phase (usually accompanied with the emergence of two-dimensional topological edge states), and could also be utilized in engineering the high efficiency ellipticity detector of infrared and terahertz radiation [S. N. Danilov et al., J. Appl. Phys. 105, 013106 (2009), 10.1063/1.3056393]. Additionally, within the same theoretical framework, we also investigate the interplay effect of structure inversion asymmetry and bulk inversion asymmetry and the pure spin currents driven by linearly polarized light in HgTe QWs.

Wave modeling in a cylindrical non-uniform helicon discharge

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chang, L.; Hole, M. J.; Caneses, J. F.

2012-08-15

A radio frequency field solver based on Maxwell's equations and a cold plasma dielectric tensor is employed to describe wave phenomena observed in a cylindrical non-uniform helicon discharge. The experiment is carried out on a recently built linear plasma-material interaction machine: The magnetized plasma interaction experiment [Blackwell et al., Plasma Sources Sci. Technol. (submitted)], in which both plasma density and static magnetic field are functions of axial position. The field strength increases by a factor of 15 from source to target plate, and the plasma density and electron temperature are radially non-uniform. With an enhancement factor of 9.5 to themore » electron-ion Coulomb collision frequency, a 12% reduction in the antenna radius, and the same other conditions as employed in the experiment, the solver produces axial and radial profiles of wave amplitude and phase that are consistent with measurements. A numerical study on the effects of axial gradient in plasma density and static magnetic field on wave propagations is performed, revealing that the helicon wave has weaker attenuation away from the antenna in a focused field compared to a uniform field. This may be consistent with observations of increased ionization efficiency and plasma production in a non-uniform field. We find that the relationship between plasma density, static magnetic field strength, and axial wavelength agrees well with a simple theory developed previously. A numerical scan of the enhancement factor to the electron-ion Coulomb collision frequency from 1 to 15 shows that the wave amplitude is lowered and the power deposited into the core plasma decreases as the enhancement factor increases, possibly due to the stronger edge heating for higher collision frequencies.« less

Adaptive vector validation in image velocimetry to minimise the influence of outlier clusters

NASA Astrophysics Data System (ADS)

Masullo, Alessandro; Theunissen, Raf

2016-03-01

The universal outlier detection scheme (Westerweel and Scarano in Exp Fluids 39:1096-1100, 2005) and the distance-weighted universal outlier detection scheme for unstructured data (Duncan et al. in Meas Sci Technol 21:057002, 2010) are the most common PIV data validation routines. However, such techniques rely on a spatial comparison of each vector with those in a fixed-size neighbourhood and their performance subsequently suffers in the presence of clusters of outliers. This paper proposes an advancement to render outlier detection more robust while reducing the probability of mistakenly invalidating correct vectors. Velocity fields undergo a preliminary evaluation in terms of local coherency, which parametrises the extent of the neighbourhood with which each vector will be compared subsequently. Such adaptivity is shown to reduce the number of undetected outliers, even when implemented in the afore validation schemes. In addition, the authors present an alternative residual definition considering vector magnitude and angle adopting a modified Gaussian-weighted distance-based averaging median. This procedure is able to adapt the degree of acceptable background fluctuations in velocity to the local displacement magnitude. The traditional, extended and recommended validation methods are numerically assessed on the basis of flow fields from an isolated vortex, a turbulent channel flow and a DNS simulation of forced isotropic turbulence. The resulting validation method is adaptive, requires no user-defined parameters and is demonstrated to yield the best performances in terms of outlier under- and over-detection. Finally, the novel validation routine is applied to the PIV analysis of experimental studies focused on the near wake behind a porous disc and on a supersonic jet, illustrating the potential gains in spatial resolution and accuracy.

Application of the Fokker-Planck molecular mixing model to turbulent scalar mixing using moment methods

NASA Astrophysics Data System (ADS)

Madadi-Kandjani, E.; Fox, R. O.; Passalacqua, A.

2017-06-01

An extended quadrature method of moments using the β kernel density function (β -EQMOM) is used to approximate solutions to the evolution equation for univariate and bivariate composition probability distribution functions (PDFs) of a passive scalar for binary and ternary mixing. The key element of interest is the molecular mixing term, which is described using the Fokker-Planck (FP) molecular mixing model. The direct numerical simulations (DNSs) of Eswaran and Pope ["Direct numerical simulations of the turbulent mixing of a passive scalar," Phys. Fluids 31, 506 (1988)] and the amplitude mapping closure (AMC) of Pope ["Mapping closures for turbulent mixing and reaction," Theor. Comput. Fluid Dyn. 2, 255 (1991)] are taken as reference solutions to establish the accuracy of the FP model in the case of binary mixing. The DNSs of Juneja and Pope ["A DNS study of turbulent mixing of two passive scalars," Phys. Fluids 8, 2161 (1996)] are used to validate the results obtained for ternary mixing. Simulations are performed with both the conditional scalar dissipation rate (CSDR) proposed by Fox [Computational Methods for Turbulent Reacting Flows (Cambridge University Press, 2003)] and the CSDR from AMC, with the scalar dissipation rate provided as input and obtained from the DNS. Using scalar moments up to fourth order, the ability of the FP model to capture the evolution of the shape of the PDF, important in turbulent mixing problems, is demonstrated. Compared to the widely used assumed β -PDF model [S. S. Girimaji, "Assumed β-pdf model for turbulent mixing: Validation and extension to multiple scalar mixing," Combust. Sci. Technol. 78, 177 (1991)], the β -EQMOM solution to the FP model more accurately describes the initial mixing process with a relatively small increase in computational cost.

Fast-ion transport in q{sub min}>2, high-β steady-state scenarios on DIII-D

DOE Office of Scientific and Technical Information (OSTI.GOV)

Holcomb, C. T.; Heidbrink, W. W.; Collins, C.

2015-05-15

Results from experiments on DIII-D [J. L. Luxon, Fusion Sci. Technol. 48, 828 (2005)] aimed at developing high β steady-state operating scenarios with high-q{sub min} confirm that fast-ion transport is a critical issue for advanced tokamak development using neutral beam injection current drive. In DIII-D, greater than 11 MW of neutral beam heating power is applied with the intent of maximizing β{sub N} and the noninductive current drive. However, in scenarios with q{sub min}>2 that target the typical range of q{sub 95}= 5–7 used in next-step steady-state reactor models, Alfvén eigenmodes cause greater fast-ion transport than classical models predict. Thismore » enhanced transport reduces the absorbed neutral beam heating power and current drive and limits the achievable β{sub N}. In contrast, similar plasmas except with q{sub min} just above 1 have approximately classical fast-ion transport. Experiments that take q{sub min}>3 plasmas to higher β{sub P} with q{sub 95}= 11–12 for testing long pulse operation exhibit regimes of better than expected thermal confinement. Compared to the standard high-q{sub min} scenario, the high β{sub P} cases have shorter slowing-down time and lower ∇β{sub fast}, and this reduces the drive for Alfvénic modes, yielding nearly classical fast-ion transport, high values of normalized confinement, β{sub N}, and noninductive current fraction. These results suggest DIII-D might obtain better performance in lower-q{sub 95}, high-q{sub min} plasmas using broader neutral beam heating profiles and increased direct electron heating power to lower the drive for Alfvén eigenmodes.« less

A dense Black Carbon network in the region of Paris, France: Implementation, objectives, and first results

NASA Astrophysics Data System (ADS)

Sciare, Jean; Petit, Jean-Eudes; Sarda-Esteve, Roland; Bonnaire, Nicolas; Gros, Valérie; Pernot, Pierre; Ghersi, Véronique; Ampe, Christophe; Songeur, Charlotte; Brugge, Benjamin; Debert, Christophe; Favez, Olivier; Le Priol, Tiphaine; Mocnik, Grisa

2013-04-01

Motivations. Road traffic and domestic wood burning emissions are two major contributors of particulate pollution in our cities. These two sources emit ultra-fine, soot containing, particles in the atmosphere, affecting health adversely, increasing morbidity and mortality from cardiovascular and respiratory conditions and casing lung cancer. A better characterization of soot containing aerosol sources in our major cities provides useful information for policy makers for assessment, implementation and monitoring of strategies to tackle air pollution issues affecting human health with additional benefits for climate change. Objectives. This study on local sources of primary Particulate Matter (PM) in the megacity of Paris is a follow-up of several programs (incl. EU-FP7-MEGAPOLI) that have shown that fine PM - in the Paris background atmosphere - is mostly secondary and imported. A network of 14 stations of Black Carbon has been implemented in the larger region of Paris to provide highly spatially resolved long term survey of local combustion aerosols. To our best knowledge, this is the first time that such densely BC network is operating over a large urban area, providing novel information on the spatial/temporal distribution of combustion aerosols within a post-industrialized megacity. Experimental. As part of the PRIMEQUAL "PREQUALIF" project, a dense Black Carbon network (of 14 stations) has been installed over the city of Paris beginning of 2012 in order to produce spatially resolved Equivalent Black Carbon (EBC) concentration maps with high time resolution through modeling and data assimilation. This network is composed of various real-time instruments (Multi-Angle Absorption Photometer, MAAP by THERMO; Multi-wavelength Aethalometers by MAGEE Scientific) implemented in contrasted sites (rural background, urban background, traffic) complementing the regulated measurements (PM, NOx) in the local air quality network AIRPARIF (http://www.airparif.asso.fr/). Contribution of imported versus local EBC is calculated using the "Lenschow" methodology (Lenschow et al., 2001), whereas the influence of domestic wood burning EBC (vs traffic) over the region of Paris is evaluated using the Aethalometer model developed by Sandradewi et al. (2008). Results and discussion. First results of this BC network are presented here including the temporal variations of EBC from wood burning (domestic heating) and fossil fuel (traffic) for the various sites (1-year observation for rural background and traffic sites; 4-year observations for urban background). The local versus imported contributions of EBC are also presented and discussed for these 2 sources. References. Lenschow, P., et al., Some ideas about the sources of PM10, Atmospheric Environment 35 Supplement No. 1 (2001) S23-S33 Sandradewi, J., et al., Using aerosol light absorption measurements for the quantitative determination of wood burning and traffic emission contributions to particulate matter, Environ. Sci. Technol., 42, 3316-3323, 2008

High hydrostatic pressure influences the in vitro response to xenobiotics in Dicentrarchus labrax liver.

PubMed

Lemaire, Benjamin; Mignolet, Eric; Debier, Cathy; Calderon, Pedro Buc; Thomé, Jean Pierre; Rees, Jean François

2016-04-01

Hydrostatic pressure (HP) increases by about 1 atmosphere (0.1MPa) for each ten-meter depth increase in the water column. This thermodynamical parameter could well influence the response to and effects of xenobiotics in the deep-sea biota, but this possibility remains largely overlooked. To grasp the extent of HP adaptation in deep-sea fish, comparative studies with living cells of surface species exposed to chemicals at high HP are required. We initially conducted experiments with precision-cut liver slices of a deep-sea fish (Coryphaenoides rupestris), co-exposed for 15h to the aryl hydrocarbon receptor (AhR) agonist 3-methylcholanthrene at HP levels representative of the surface (0.1MPa) and deep-sea (5-15MPa; i.e., 500-1500m depth) environments. The transcript levels of a suite of stress-responsive genes, such as the AhR battery CYP1A, were subsequently measured (Lemaire et al., 2012; Environ. Sci. Technol. 46, 10310-10316). Strikingly, the AhR agonist-mediated increase of CYP1A mRNA content was pressure-dependently reduced in C. rupestris. Here, the same co-exposure scenario was applied for 6 or 15h to liver slices of a surface fish, Dicentrarchus labrax, a coastal species presumably not adapted to high HP. Precision-cut liver slices of D. labrax were also used in 1h co-exposure studies with the pro-oxidant tert-butylhydroperoxide (tBHP) as to investigate the pressure-dependence of the oxidative stress response (i.e., reactive oxygen production, glutathione and lipid peroxidation status). Liver cells remained viable in all experiments (adenosine triphosphate content). High HP precluded the AhR agonist-mediated increase of CYP1A mRNA expression in D. labrax, as well as that of glutathione peroxidase, and significantly reduced that of heat shock protein 70. High HP (1h) also tended per se to increase the level of oxidative stress in liver cells of the surface fish. Trends to an increased resistance to tBHP were also noted. Whether the latter observation truly reflects a protective response to oxidative stress will be addressed in future co-exposure studies with both surface and deep-sea fish liver cells, using additional pro-oxidant chemicals. Altogether, data on CYP1A inducibility with D. labrax and C. rupestris support the view that high HP represses AhR signaling in marine fishes, and that only species adapted to thrive in the deep-sea have evolved the molecular adaptations necessary to counteract to some extent this inhibition. Copyright © 2016 Elsevier B.V. All rights reserved.

OPENING REMARKS: SciDAC: Scientific Discovery through Advanced Computing

NASA Astrophysics Data System (ADS)

Strayer, Michael

2005-01-01

Good morning. Welcome to SciDAC 2005 and San Francisco. SciDAC is all about computational science and scientific discovery. In a large sense, computational science characterizes SciDAC and its intent is change. It transforms both our approach and our understanding of science. It opens new doors and crosses traditional boundaries while seeking discovery. In terms of twentieth century methodologies, computational science may be said to be transformational. There are a number of examples to this point. First are the sciences that encompass climate modeling. The application of computational science has in essence created the field of climate modeling. This community is now international in scope and has provided precision results that are challenging our understanding of our environment. A second example is that of lattice quantum chromodynamics. Lattice QCD, while adding precision and insight to our fundamental understanding of strong interaction dynamics, has transformed our approach to particle and nuclear science. The individual investigator approach has evolved to teams of scientists from different disciplines working side-by-side towards a common goal. SciDAC is also undergoing a transformation. This meeting is a prime example. Last year it was a small programmatic meeting tracking progress in SciDAC. This year, we have a major computational science meeting with a variety of disciplines and enabling technologies represented. SciDAC 2005 should position itself as a new corner stone for Computational Science and its impact on science. As we look to the immediate future, FY2006 will bring a new cycle to SciDAC. Most of the program elements of SciDAC will be re-competed in FY2006. The re-competition will involve new instruments for computational science, new approaches for collaboration, as well as new disciplines. There will be new opportunities for virtual experiments in carbon sequestration, fusion, and nuclear power and nuclear waste, as well as collaborations with industry and virtual prototyping. New instruments of collaboration will include institutes and centers while summer schools, workshops and outreach will invite new talent and expertise. Computational science adds new dimensions to science and its practice. Disciplines of fusion, accelerator science, and combustion are poised to blur the boundaries between pure and applied science. As we open the door into FY2006 we shall see a landscape of new scientific challenges: in biology, chemistry, materials, and astrophysics to name a few. The enabling technologies of SciDAC have been transformational as drivers of change. Planning for major new software systems assumes a base line employing Common Component Architectures and this has become a household word for new software projects. While grid algorithms and mesh refinement software have transformed applications software, data management and visualization have transformed our understanding of science from data. The Gordon Bell prize now seems to be dominated by computational science and solvers developed by TOPS ISIC. The priorities of the Office of Science in the Department of Energy are clear. The 20 year facilities plan is driven by new science. High performance computing is placed amongst the two highest priorities. Moore's law says that by the end of the next cycle of SciDAC we shall have peta-flop computers. The challenges of petascale computing are enormous. These and the associated computational science are the highest priorities for computing within the Office of Science. Our effort in Leadership Class computing is just a first step towards this goal. Clearly, computational science at this scale will face enormous challenges and possibilities. Performance evaluation and prediction will be critical to unraveling the needed software technologies. We must not lose sight of our overarching goal—that of scientific discovery. Science does not stand still and the landscape of science discovery and computing holds immense promise. In this environment, I believe it is necessary to institute a system of science based performance metrics to help quantify our progress towards science goals and scientific computing. As a final comment I would like to reaffirm that the shifting landscapes of science will force changes to our computational sciences, and leave you with the quote from Richard Hamming, 'The purpose of computing is insight, not numbers'.

Exploring a Model of Situated Professional Development: Impact on Classroom Practice

NASA Astrophysics Data System (ADS)

Singer, Jonathan; Lotter, Christine; Feller, Robert; Gates, Harry

2011-04-01

A hallmark of current science education reform involves teaching through inquiry. However, the widespread use of inquiry-based instruction in many classrooms has not occurred (Roehrig and Luft in Int J Sci Educ 26:3-24, 2004; Schneider et al. in J Res Sci Teach 42:283-312, 2005). The purpose of this study was to investigate the impact of a professional development program on middle school science teachers' ability to enact inquiry-based pedagogical practices. Data were generated through evaluation of teacher practice using the Reformed Teaching Observation Protocol (RTOP) (Sawada et al. in School Sci Math 102:245-253, 2002) at three distinct junctures, before, during, and after the professional development treatment. Analysis of teacher-participant post-institute reflections was then utilized to determine the perceived role of the various institute components. Statistical significant changes in RTOP scores indicated that the teachers were able to successfully transfer the enactment of the inquiry-based practices into their classrooms. The subsequent discussion provides connection between these pedagogical changes with use of professional development strategies that provide a situated learning environment.

Neuroprotective effects of perflurocarbon (oxycyte) after contusive spinal cord injury.

PubMed

Yacoub, Adly; Hajec, Marygrace C; Stanger, Richard; Wan, Wen; Young, Harold; Mathern, Bruce E

2014-02-01

Spinal cord injury (SCI) often results in irreversible and permanent neurological deficits and long-term disability. Vasospasm, hemorrhage, and loss of microvessels create an ischemic environment at the site of contusive or compressive SCI and initiate the secondary injury cascades leading to progressive tissue damage and severely decreased functional outcome. Although the initial mechanical destructive events cannot be reversed, secondary injury damage occurs over several hours to weeks, a time frame during which therapeutic intervention could be achieved. One essential component of secondary injury cascade is the reduction in spinal cord blood flow with resultant decrease in oxygen delivery. Our group has recently shown that administration of fluorocarbon (Oxycyte) significantly increased parenchymal tissue oxygen levels during the usual postinjury hypoxic phase, and fluorocarbon has been shown to be effective in stroke and head injury. In the current study, we assessed the beneficial effects of Oxycyte after a moderate-to-severe contusion SCI was simulated in adult Long-Evans hooded rats. Histopathology and immunohistochemical analysis showed that the administration of 5 mL/kg of Oxycyte perfluorocarbon (60% emulsion) after SCI dramatically reduced destruction of spinal cord anatomy and resulted in a marked decrease of lesion area, less cell death, and greater white matter sparing at 7 and 42 days postinjury. Terminal deoxynucleotidyl transferase dUTP nick end labeling staining showed a significant reduced number of apoptotic cells in Oxycyte-treated animals, compared to the saline group. Collectively, these results demonstrate the potential neuroprotective effect of Oxycyte treatment after SCI, and its beneficial effects may be, in part, a result of reducing apoptotic cell death and tissue sparing. Further studies to determine the most efficacious Oxycyte dose and its mechanisms of protection are warranted.

Restoration of motor function following spinal cord injury via optimal control of intraspinal microstimulation: toward a next generation closed-loop neural prosthesis

PubMed Central

Grahn, Peter J.; Mallory, Grant W.; Berry, B. Michael; Hachmann, Jan T.; Lobel, Darlene A.; Lujan, J. Luis

2014-01-01

Movement is planned and coordinated by the brain and carried out by contracting muscles acting on specific joints. Motor commands initiated in the brain travel through descending pathways in the spinal cord to effector motor neurons before reaching target muscles. Damage to these pathways by spinal cord injury (SCI) can result in paralysis below the injury level. However, the planning and coordination centers of the brain, as well as peripheral nerves and the muscles that they act upon, remain functional. Neuroprosthetic devices can restore motor function following SCI by direct electrical stimulation of the neuromuscular system. Unfortunately, conventional neuroprosthetic techniques are limited by a myriad of factors that include, but are not limited to, a lack of characterization of non-linear input/output system dynamics, mechanical coupling, limited number of degrees of freedom, high power consumption, large device size, and rapid onset of muscle fatigue. Wireless multi-channel closed-loop neuroprostheses that integrate command signals from the brain with sensor-based feedback from the environment and the system's state offer the possibility of increasing device performance, ultimately improving quality of life for people with SCI. In this manuscript, we review neuroprosthetic technology for improving functional restoration following SCI and describe brain-machine interfaces suitable for control of neuroprosthetic systems with multiple degrees of freedom. Additionally, we discuss novel stimulation paradigms that can improve synergy with higher planning centers and improve fatigue-resistant activation of paralyzed muscles. In the near future, integration of these technologies will provide SCI survivors with versatile closed-loop neuroprosthetic systems for restoring function to paralyzed muscles. PMID:25278830

Student goal orientation in learning inquiry skills with modifiable software advisors

NASA Astrophysics Data System (ADS)

Shimoda, Todd A.; White, Barbara Y.; Frederiksen, John R.

2002-03-01

A computer support environment (SCI-WISE) for learning and doing science inquiry projects was designed. SCI-WISE incorporates software advisors that give general advice about a skill such as hypothesizing. By giving general advice (rather than step-by-step procedures), the system is intended to help students conduct experiments that are more epistemologically authentic. Also, students using SCI-WISE can select the type of advice the advisors give and when they give advice, as well as modify the advisors' knowledge bases. The system is based partly on a theoretical framework of levels of agency and goal orientation. This framework assumes that giving students higher levels of agency facilitates higher-level goal orientations (such as mastery or knowledge building as opposed to task completion) that in turn produce higher levels of competence. A study of sixth grade science students was conducted. Students took a pretest questionnaire that measured their goal orientations for science projects and their inquiry skills. The students worked in pairs on an open-ended inquiry project that requires complex reasoning about human memory. The students used one of two versions of SCI-WISE - one that was modifiable and one that was not. After finishing the project, the students took a posttest questionnaire similar to the pretest, and evaluated the version of the system they used. The main results showed that (a) there was no correlation of goal orientation with grade point average, (b) knowledge-oriented students using the modifiable version tended to rate SCI-WISE more helpful than task-oriented students, and (c) knowledge-oriented pairs using the nonmodifiable version tended to have higher posttest inquiry skills scores than other pair types.

SunLine Transit Agency Advanced Technology Fuel Cell Bus Evaluation: Fourth Results Report

DOT National Transportation Integrated Search

2013-01-01

SunLine Transit Agency provides public transit services to the Coachella Valley area of California. SunLine has demonstrated hydrogen and fuel cell bus technologies for more than 10 years. In May 2010, SunLine began demonstrating the advanced technol...

Los Angeles congestion reduction demonstration (Metro ExpressLanes) program. National evaluation : surveys, interviews, and workshops test plan.

DOT National Transportation Integrated Search

1997-09-01

Integration of intelligent transportation systems (ITS) within a metropolitan area is crucial for effective deployment. The Early Deployment Planning (EDP) Process is one tool that allows transportation officials to plan for and implement ITS technol...

University Research Initiative Program for Combat Readiness

DTIC Science & Technology

1999-05-01

found in sponge-associated bacteria Micrococcus luteus (Bultel-Ponce et al., 1998). Such compounds have antimicrobial activity. Water contact angles...Guyot, M. 1998. Metabolites from the sponge-associated bacterium Micrococcus luteus. J. Mar. Biotechnol. 6:233-236. 3. Incze, B.I., Sea Technol. 1996, 37

Passive hind-limb cycling improves cardiac function and reduces cardiovascular disease risk in experimental spinal cord injury.

PubMed

West, Christopher R; Crawford, Mark A; Poormasjedi-Meibod, Malihe-Sadat; Currie, Katharine D; Fallavollita, Andre; Yuen, Violet; McNeill, John H; Krassioukov, Andrei V

2014-04-15

Spinal cord injury (SCI) causes altered autonomic control and severe physical deconditioning that converge to drive maladaptive cardiac remodelling. We used a clinically relevant experimental model to investigate the cardio-metabolic responses to SCI and to establish whether passive hind-limb cycling elicits a cardio-protective effect. Initially, 21 male Wistar rats were evenly assigned to three groups: uninjured control (CON), T3 complete SCI (SCI) or T3 complete SCI plus passive hind-limb cycling (SCI-EX; 2 × 30 min day(-1), 5 days week(-1) for 4 weeks beginning 6 days post-SCI). On day 32, cardio-metabolic function was assessed using in vivo echocardiography, ex vivo working heart assessments, cardiac histology/molecular biology and blood lipid profiles. Twelve additional rats (n = 6 SCI and n = 6 SCI-EX) underwent in vivo echocardiography and basal haemodynamic assessments pre-SCI and at days 7, 14 and 32 post-SCI to track temporal cardiovascular changes. Compared with CON, SCI exhibited a rapid and sustained reduction in left ventricular dimensions and function that ultimately manifested as reduced contractility, increased myocardial collagen deposition and an up-regulation of transforming growth factor beta-1 (TGFβ1) and mothers against decapentaplegic homolog 3 (Smad3) mRNA. For SCI-EX, the initial reduction in left ventricular dimensions and function at day 7 post-SCI was completely reversed by day 32 post-SCI, and there were no differences in myocardial contractility between SCI-EX and CON. Collagen deposition was similar between SCI-EX and CON. TGFβ1 and Smad3 were down-regulated in SCI-EX. Blood lipid profiles were improved in SCI-EX versus SCI. We provide compelling novel evidence that passive hind-limb cycling prevents cardiac dysfunction and reduces cardiovascular disease risk in experimental SCI.

Mixed-reality exercise effects on participation of individuals with spinal cord injuries and developmental disabilities: a pilot study.

PubMed

Heyn, Patricia C; Baumgardner, Chad A; McLachlan, Leslie; Bodine, Cathy

2014-01-01

The purpose of this pilot study was to investigate the effectiveness of a mixed-reality (MR) exercise environment on engagement and enjoyment levels of individuals with spinal cord injury (SCI) and intellectual and developmental disabilities (IDD). Six people participated in this cross-sectional, observational pilot study involving one MR exercise trial. The augmented reality environment was based on a first-person perspective video of a scenic biking/walking trail in Colorado. Males and females (mean age, 43.3 ± 13.7 years) were recruited from a research database for their participation in previous clinical studies. Of the 6 participants, 2 had SCI, 2 had IDD, and 2 were without disability. The primary outcome measurement of this pilot study was the self-reported engagement and enjoyment level of each participant after the exercise trial. All participants reported increased levels of engagement, enjoyment, and immersion involving the MR exercise environment as well as positive feedback recommending this type of exercise approach to peers with similar disabilities. All the participants reported higher than normal levels of enjoyment and 66.7% reported higher than normal levels of being on a real trail. Participants' feedback suggested that the MR environment could be entertaining, motivating, and engaging for users with disabilities, resulting in a foundation for further development of this technology for use in individuals with cognitive and physical disabilities.

GeoSciML version 3: A GML application for geologic information

NASA Astrophysics Data System (ADS)

International Union of Geological Sciences., I. C.; Richard, S. M.

2011-12-01

After 2 years of testing and development, XML schema for GeoSciML version 3 are now ready for application deployment. GeoSciML draws from many geoscience data modelling efforts to establish a common suite of feature types to represent information associated with geologic maps (materials, structures, and geologic units) and observations including structure data, samples, and chemical analyses. After extensive testing and use case analysis, in December 2008 the CGI Interoperability Working Group (IWG) released GeoSciML 2.0 as an application schema for basic geological information. GeoSciML 2.0 is in use to deliver geologic data by the OneGeology Europe portal, the Geological Survey of Canada Groundwater Information Network (wet GIN), and the Auscope Mineral Resources portal. GeoSciML to version 3.0 is updated to OGC Geography Markup Language v3.2, re-engineered patterns for association of element values with controlled vocabulary concepts, incorporation of ISO19156 Observation and Measurement constructs for representing numeric and categorical values and for representing analytical data, incorporation of EarthResourceML to represent mineral occurrences and mines, incorporation of the GeoTime model to represent GSSP and stratigraphic time scale, and refactoring of the GeoSciML namespace to follow emerging ISO practices for decoupling of dependencies between standardized namespaces. These changes will make it easier for data providers to link to standard vocabulary and registry services. The depth and breadth of GeoSciML remains largely unchanged, covering the representation of geologic units, earth materials and geologic structures. ISO19156 elements and patterns are used to represent sampling features such as boreholes and rock samples, as well as geochemical and geochronologic measurements. Geologic structures include shear displacement structures (brittle faults and ductile shears), contacts, folds, foliations, lineations and structures with no preferred orientation (e.g. 'miarolitic cavities'). The Earth material package allows for the description of both individual components, such as minerals, and compound materials, such as rocks or unconsolidated materials. Provision is made for alteration, weathering, metamorphism, particle geometry, fabric, and petrophysical descriptions. Mapped features describe the shape of the geological features using standard GML geometries, such as polygons, lines, points or 3D volumes. Geological events provide the age, process and environment of formation of geological features. The Earth Resource section includes features to represent mineral occurrences and mines and associated human activities independently. This addition allows description of resources and reserves that can comply with national and internationally accepted reporting codes. GeoSciML v3 is under consideration as the data model for INSPIRE annex 2 geologic reporting in Europe.

Plasma iron levels appraised 15 days after spinal cord injury in a limb movement animal model.

PubMed

Reis, F M; Esteves, A M; Tufik, S; de Mello, M T

2011-03-01

Experimental, controlled trial. The purpose of this study was to evaluate plasma iron and transferrin levels in a limb movement animal model with spinal cord injury (SCI). Universidade Federal de São Paulo, Departamento de Psicobiologia. In all, 72 male Wistar rats aged 90 days were divided into four groups: (1) acute SCI (1 day, SCI1), (2) 3 days post-SCI (SCI3), (3) 7 days post-SCI (SCI7) and (4) 15 days post-SCI (SCI15). Each of these groups had corresponding control (CTRL) and SHAM groups. Plasma iron and transferrin levels of the different groups were analyzed using a one-way analysis of variance (ANOVA) followed by Tukey's test. We found a significant reduction in iron plasma levels after SCI compared with the CTRL group: SCI1 (CTRL: 175±10.58 μg dl(-1); SCI: 108.28±11.7 μg dl(-1)), SCI3 (CTRL: 195.5±11.00 μg dl(-1); SCI: 127.88±12.63 μg dl(-1)), SCI7 (CTRL: 186±2.97 μg dl(-1); SCI: 89.2±15.39 μg dl(-1)) and SCI15 (CTRL: 163±5.48 μg dl(-1); SCI: 124.44±10.30 μg dl(-1)) (P<0.05; ANOVA). The SHAM1 group demonstrated a reduction in iron plasma after acute SCI (CTRL: 175±10.58 μg dl(-1); SHAM: 114.60±7.81 μg dl(-1)) (P<0.05; ANOVA). Reduced iron metabolism after SCI may be one of the mechanisms involved in the pathogenesis of sleep-related movement disorders.

The SDF-1/CXCR4 axis promotes recovery after spinal cord injury by mediating bone marrow-derived from mesenchymal stem cells

PubMed Central

Wang, Xiao; Zhang, Yong-Le; Zhang, Ya-Dong; Xue, Feng

2017-01-01

This study aims to explore the role of the SDF-1/CXCR4 axis in mediating BMSCs and SCI recovery. BMSCs were collected and SCI rat models were established. Wistar rats were assigned into the blank control, sham, SCI, SCI + BMSCs, SCI + BMSCs + SDF-1, SCI + BMSCs + AMD3100 (an inhibitor of SDF-1/CXCR4 axis) and SCI + BMSCs + SDF-1 + AMD3100 groups. Hind limb motor function was measured 7, 14, 21 and 28 days after operation. qRT-PCR, western blotting and ELISA was performed to determine the expressions of SDF-1, CXCR4, NGF, BDNF, GFAP and GAP-43, TNF-α, IL-1β, L-6 and IFN-γ. Hind limb motor function scores 7 days after the operation were reduced in the SCI rats of the blank control and sham groups. Hind limb function was found to be better in the SCI + BMSCs and SCI + BMSCs + SDF-1 groups than in the SCI, SCI + BMSCs + AMD3100 and SCI + BMSCs + SDF-1 + AMD3100 groups 14, 21 and 28 days after operation. Furthermore, the SCI group had lower SDF-1, CXCR4, NGF, BDNF and GAP-43 expressions but higher GFAP, TNF-α, IL-1β, IL-6 and IFN-γ than the blank control and sham groups 28 days after operation. While, the SCI + BMSCs, SCI + BMSCs + SDF-1 and SCI + BMSCs + SDF-1 + AMD3100 groups displayed opposite trends to the SCI and SCI + BMSCs + AMD3100 groups. In conclusion, SDF-1/CXCR4 axis promotes recovery after SCI by mediating BMSCs. PMID:28099928

CAPSTONE SENIOR DESIGN - SUPRAMOLECULAR PROTON EXCHANGE MEMBRANES FOR FUEL CELLS

EPA Science Inventory

In order to assume a leading role in the burgeoning hydrogen economy, new infrastructure will be required for fuel cell manufacturing and R&D capabilities. The objective of this proposal is the development of a new generation of advanced proton exchange membrane (PEM) technol...

Water-Soluble Nanodiamond (Postprint)

DTIC Science & Technology

2012-03-01

Lim, D.-S. Tribological behavior of PTFE film with nanodiamond. Surf. Coat. Technol. 2004, 188−189, 534−538. (9) Williams , O. A.; Nesladek, M.; Daenen...properties and applications. Russ. Chem. Rev. 2001, 70, 607−626. (27) Liang, Y.; Meinhardt, T.; Jarre, G.; Ozawa, M.; Vrodijak, P.; Scholl , A

THE U.S. ENVIRONMENTAL PROTECTION AGENCY'S SITE EMERGING TECHNOLOGY PROGRAM

EPA Science Inventory

Under the SITE Emerging Technology Program, the U.S. Environmental Protection Agency is seeking to foster the further development of technol- ogies that have been successfully tested at bench-scale and are now ready for pilot-scale testing, prior to field- or full-scale demonstra...

BIOREMEDIATION OF HAZARDOUS WASTES - RESEARCH, DEVELOPMENT AND FIELD EVALUATIONS - 1995

EPA Science Inventory

The proceedings of the 1995 Symposium on Bioremediation of Hazardous Wastes, hosted by the Office of Research and Development (ORD) of the EPA in Rye Brook, New York. he symposium was the eighth annual meeting for the presentation of research conducted by EPA's Biosystems Technol...

Passive hind-limb cycling improves cardiac function and reduces cardiovascular disease risk in experimental spinal cord injury

PubMed Central

West, Christopher R; Crawford, Mark A; Poormasjedi-Meibod, Malihe-Sadat; Currie, Katharine D; Fallavollita, Andre; Yuen, Violet; McNeill, John H; Krassioukov, Andrei V

2014-01-01

Spinal cord injury (SCI) causes altered autonomic control and severe physical deconditioning that converge to drive maladaptive cardiac remodelling. We used a clinically relevant experimental model to investigate the cardio-metabolic responses to SCI and to establish whether passive hind-limb cycling elicits a cardio-protective effect. Initially, 21 male Wistar rats were evenly assigned to three groups: uninjured control (CON), T3 complete SCI (SCI) or T3 complete SCI plus passive hind-limb cycling (SCI-EX; 2 × 30 min day−1, 5 days week−1 for 4 weeks beginning 6 days post-SCI). On day 32, cardio-metabolic function was assessed using in vivo echocardiography, ex vivo working heart assessments, cardiac histology/molecular biology and blood lipid profiles. Twelve additional rats (n = 6 SCI and n = 6 SCI-EX) underwent in vivo echocardiography and basal haemodynamic assessments pre-SCI and at days 7, 14 and 32 post-SCI to track temporal cardiovascular changes. Compared with CON, SCI exhibited a rapid and sustained reduction in left ventricular dimensions and function that ultimately manifested as reduced contractility, increased myocardial collagen deposition and an up-regulation of transforming growth factor beta-1 (TGFβ1) and mothers against decapentaplegic homolog 3 (Smad3) mRNA. For SCI-EX, the initial reduction in left ventricular dimensions and function at day 7 post-SCI was completely reversed by day 32 post-SCI, and there were no differences in myocardial contractility between SCI-EX and CON. Collagen deposition was similar between SCI-EX and CON. TGFβ1 and Smad3 were down-regulated in SCI-EX. Blood lipid profiles were improved in SCI-EX versus SCI. We provide compelling novel evidence that passive hind-limb cycling prevents cardiac dysfunction and reduces cardiovascular disease risk in experimental SCI. PMID:24535438

A miniature laser ablation mass spectrometer for quantitative in situ chemical composition investigation of lunar surface

NASA Astrophysics Data System (ADS)

Brigitte Neuland, Maike; Grimaudo, Valentine; Mezger, Klaus; Moreno-García, Pavel; Riedo, Andreas; Tulej, Marek; Wurz, Peter

2016-04-01

The chemical composition of planetary bodies, moons, comets and asteroids is a key to understand their origin and evolution [Wurz,2009]. Measurements of the elemental and isotopic composition of rocks yield information about the formation of the planetary body, its evolution and following processes shaping the planetary surface. From the elemental composition, conclusions about modal mineralogy and petrology can be drawn. Isotope ratios are a sensitive indicator for past events on the planetary body and yield information about origin and transformation of the matter, back to events that occurred in the early solar system. Finally, measurements of radiogenic isotopes make it possible to carry out dating analyses. All these topics, particularly in situ dating analyses, quantitative elemental and highly accurate isotopic composition measurements, are top priority scientific questions for future lunar missions. An instrument for precise measurements of chemical composition will be a key element in scientific payloads of future landers or rovers on lunar surface. We present a miniature laser ablation mass spectrometer (LMS) designed for in situ research in planetary and space science and optimised for measurements of the chemical composition of rocks and soils on a planetary surface. By means of measurements of standard reference materials we demonstrate that LMS is a suitable instrument for in situ measurements of elemental and isotopic composition with high precision and accuracy. Measurements of soil standards are used to confirm known sensitivity coefficients of the instrument and to prove the power of LMS for quantitative elemental analyses [Neuland,2016]. For demonstration of the capability of LMS to measure the chemical composition of extraterrestrial material we use a sample of Allende meteorite [Neuland,2014]. Investigations of layered samples confirm the high spatial resolution in vertical direction of LMS [Grimaudo,2015], which allows in situ studying of past surface processes on a planetary surface. Analyses of Pb isotopes show that the statistical uncertainty for the age determination by LMS is about ±100 Myrs, if abundance of 206Pb and 207Pb is 20ppm and 2ppm respectively [Riedo,2013]. These Pb isotopes have abundances of tens to hundreds of ppm in lunar KREEP [Nemchin,2008]. We demonstrate the measurement capabilities of LMS for petrographic and mineralogical analyses, for isotopic studies and dating analyses, which are key topics for future missions to the Moon. Having the LMS instrument installed on a lunar rover would allow measuring the chemical composition of many rock and soil samples, distributed over a certain area, inside the South Pole Aitken Basin for example. LMS measurements would yield valuable conclusions about age and mineralogy. References: [Wurz,2009]Wurz,P. et al. 2009, AIP Conf.Proc., CP1144:70-75. [Grimaudo,2015]Grimaudo, V. et al. 2015, Anal.Chem. 87: 2037-2041. [Neuland,2014]Neuland, M.B. et al. 2014, Planet.Space Sci.101:196-209. [Neuland,2016]Neuland M.B. et al. 2016, Meas. Sci. Technol.,submitted. [Riedo,2013]Riedo A. et al., 2013 Planet. Space Sci. 87: 1-13. [Nemchin,2008]Nemchin et al., 2008 Geochim. Cosmochim.Acta 72:668-689.

From Sci-Fi to Reality--Mobile Robots Get the Job Done

ERIC Educational Resources Information Center

Roman, Harry T.

2006-01-01

Robots are simply computers that can interact with their environment. Some are fixed in place in industrial assembly plants for cars, appliances, micro electronic circuitry, and pharmaceuticals. Another important category of robots is the mobiles, machines that can be driven to the workplace, often designed for hazardous duty operation or…

Best Sci-Tech Books of 2008

ERIC Educational Resources Information Center

Sapp, Gregg

2009-01-01

In tight economic times, the concerns and issues of science, viewed as not having enough practical value, can get pushed aside. But the top science books of 2008 demonstrate how science more often than not pays for itself. What's more practical than food (Tomorrow's Table), health (Our Daily Meds), the environment (The Hot Topics), or even--sex…

"Disorienting, Fun or Meaningful?": Looking beyond the Boundaries of the Museum

ERIC Educational Resources Information Center

Birmingham, Daniel

2016-01-01

A growing body of research highlights how informal science learning environments (ISLE's) can alter modes of participation in science for youth who are traditionally marginalized in science (Calabrese Barton and Tan in "J Learn Sci" 19(2):187-229, 2010). While these findings reveal successful examples of ISLE's potential to bridge…

SciJourn Is Magic: Construction of a Science Journalism Community of Practice

ERIC Educational Resources Information Center

Nicholas, Celeste R.

2017-01-01

This article is the first to describe the discoursal construction of an adolescent community of practice (CoP) in a non-school setting. CoPs can provide optimal learning environments. The adolescent community centered around science journalism and positioned itself dichotomously in relationship to school literacy practices. The analysis focuses on…

Comparison of gait performance on different environmental settings for patients with chronic spinal cord injury.

PubMed

Olmos, L E; Freixes, O; Gatti, M A; Cozzo, D A; Fernandez, S A; Vila, C J; Agrati, P E; Rubel, I F

2008-05-01

Observational cross-section study. The objective of our study was to determine if the influence of a community environment would impact on ASIA D spinal cord injured (SCI) gait performance patients. Our main hypothesis is that an outdoor community environment may influence gait speed and endurance on community ambulating patients. Ten-Meter Walking (10MWT) and Six-Minute Walking (6MWT) tests were performed on community ambulating SCI research participants (n=18) in two different environmental conditions: (1) Experimental (indoors Gymnasium) and (2) Natural (community setting). Average gait speed and endurance values were obtained for the two different conditions and analyzed for statistical significance on the nonparametric two-tailed Wilcoxon signed rank test. While no difference was observed on the 10MWT we found an improvement on gait performance on the 6 MWT on a community setting. Our study showed mixed results on environmental influence on gait speed and endurance on ASIA D patient population. While there is no difference on the 10 MWT, there is an improvement on gait performance on the communitary 6MWT.

Discrepancies between implicit and explicit self-concepts of intelligence: relations to modesty, narcissism, and achievement motivation

PubMed Central

Gerstenberg, Friederike X. R.; Imhoff, Roland; Banse, Rainer; Schmitt, Manfred

2014-01-01

Previous research has shown that different configurations of the implicit self-concept of intelligence (iSCI) and the explicit self-concept of intelligence (eSCI) are consistently related to individuals’ performance on different intelligence tests (Dislich etal., 2012). The results indicated that any discrepant configuration between the iSCI and the eSCI impairs performance. In the present study, how correspondence between the iSCI and the eSCI is related to intelligence test performance as well as personality traits of modesty (low eSCI, high iSCI), narcissism (high eSCI, low iSCI), and achievement motivation was investigated. Furthermore, a moderated mediation analysis showed that the relation between the iSCI–eSCI configurations and intelligence test performance was mediated by achievement motivation for modest individuals. PMID:24575063

INNOVATIVE TECHNOLOGY EVALUATION REPORT: RADIO FREQUENCY HEATING, KAI TECHNOLOGIES, INC.

EPA Science Inventory

A demonstration of KAI Technologies in-situ radio frequency heating system for soil treatment was conducted from January 1994 to July 1994 at Kelly Air Force Base in San Antonio, Texas. This demonstration was conducted as a joint effort between the USEPA and the USAF. The technol...

Maskless Lithography Using Surface Plasmon Enhanced Illumination

DTIC Science & Technology

2007-04-30

Dale Larson Figure 1. Nanohole array probes exhibiting extraordinary optical transmission of light with a high degree of collimation. Left: a bull’s...Technol. B 22, 3552-3556 (2004). 2. Stark, P., Halleck, A. E. & Larson, D. N. Short order nanohole arrays in metals for highly sensitive probing of local

The Phases Differential Astrometry Data Archive. 5. Candidate Substellar Companions to Binary Systems

DTIC Science & Technology

2010-12-01

Mathematics and Astronomy , 105-24, California Institute of Technology, Pasadena, CA 91125, USA 5 Nicolaus Copernicus Astronomical Center, Polish Academy...Blind Test with support from NASA contract NAS7-03001 (JPL 1336910). PHASES is funded in part by the California Institute of Technol- ogy Astronomy

Development of Microbial and Enzymatic Fuel Cells for Bio-Inspired Power Sources

DTIC Science & Technology

2009-03-01

that of the oxidation of NADH as possible.[30] A variety of organic mediators have been studied for the anode, including phenazines ,[38] dyes,[39,40...glucose-6-phosphate dehydrogenase on the rotating graphite disc electrode modified with phenazine methosulfate. Enzyme Microb. Technol. 1993, 15 (6), 525

Object-Oriented Dynamic Bayesian Network-Templates for Modelling Mechatronic Systems

DTIC Science & Technology

2002-05-04

daimlerchrysler.com Abstract are widespread. For modelling mechanical systems The object-oriented paradigma is a new but proven technol- ADAMS [31 or...hardware (sub-)systems. On the Software side thermal flow or hydraulics, see Figure 1. It also contains a the object-oriented paradigma is by now (at

Length of stay and medical stability for spinal cord-injured patients on admission to an inpatient rehabilitation hospital: a comparison between a model SCI trauma center and non-SCI trauma center.

PubMed

Ploumis, A; Kolli, S; Patrick, M; Owens, M; Beris, A; Marino, R J

2011-03-01

Retrospective database review. To compare lengths of stay (LOS), pressure ulcers and readmissions to the acute care hospital of patients admitted to the inpatient rehabilitation facility (IRF) from a model spinal cord injury (SCI) trauma center or from a non-SCI acute hospital. Only sparse data exist comparing the status of patients admitted to IRF from a model SCI trauma center or from a non-SCI acute hospital. Acute care, IRF and total LOS were compared between patients transferred to IRF from the SCI center (n=78) and from non-SCI centers (n=131). The percentages of pressure ulcers on admission to IRF and transfer back to acute care were also compared. Patients admitted to IRF from the SCI trauma center (SCI TC) had significantly shorter (P=0.01) acute care LOS and total LOS compared with patients admitted from non-SCI TCs. By neurological category, acute-care LOS was less for all groups admitted from the SCI center, but statistically significant only for tetraplegia. There was no significant difference in the incidence of readmissions to acute care from IRF. More patients from non-SCI centers (34%) than SCI centers (12%) had pressure ulcers (P<0.001). Acute care in organized SCI TCs before transfer to IRF can significantly lower acute-care LOS or total LOS and incidence of pressure ulcers compared with non-SCI TCs. Patients admitted to IRF from SCI TCs are no more likely to be sent back to an acute hospital than those from non-SCI TCs.

Ammonium Oxidation Under Iron Reducing Conditions: Environmental Factors Characterization and Process Optimization

NASA Astrophysics Data System (ADS)

Huang, Shan; Ruiz, Melany; Jaffe, Peter

2015-04-01

Ammonium (NH4+) oxidation coupled to iron (Fe) reduction in the absence of oxygen and nitrate/nitrite (NO3-/NO2-) has been reported by several investigators and is referred to as Feammox. Feammox is a biological reaction, where Fe(III) is the electron acceptor, which is reduced to Fe(II), and NH4+ is the electron donor, which is oxidized to NO2-. An Acidimicrobiaceae bacterium named A6, a previously unreported species in the Acidimicrobiaceae family, has been identified as being responsible for the Feammox process(1, 2) Feammox process was noted in riparian wetland soils in New Jersey(1,3), in tropical rainforest soils in Puerto Rico (4) and in paddy soils in China (5). In addition to these published locations, Feammox process was also found in samples collected from a series of local wetland-, upland-, as well as storm-water detention pond-sediments in New Jersey, river sediments from South Carolina, and forested soils near an acid mine drainage (Dabaoshan, Guangdong province) in China. Using primers acm342f - 439r (2), Acidimicrobiaceae bacterium A6 was detected in samples where Feammox was observed, after strictly anaerobic incubations. According to a canonical correspondence analysis with environmental characteristics and soil microbial communities, the species-environment relationship indicated that pH and Fe oxides content were the primary factors controlling Feammox process. Anaerobic incubations of Feammox enrichment cultures adjusted to different pH, revealed that the optimal pH for Feammox is 4 ~ 5, and the reaction does not proceed when pH > 7. No correlation was found between the distributions of Feammox bacteria and other NH4+ oxidation bacteria. Pure Acidimicrobiaceae bacterium A6 strain was isolated in an autotrophic medium, from an active Feammox membrane reactor (A6 was enriched to 65.8% of the total bacteria). A 13C labeled CO2 amendment was conducted, and the 13C in cells of A6 increased from 1.80% to 10.3% after 14 days incubation. In a separate incubation, 15NH4Cl was added with a final concentration of 0.5 mmol L-1, and 0.133 mmol L-1 of 15NO2- was detected, while no 15NO3- was produced. In Feammox culture amended with different Fe(III) sources, Feammox reaction proceeded only when Fe oxides (ferrihydrite or goethite) were supplied, whereas samples incubated with ferric chloride or ferric citrate showed no measurable NH4+ oxidation. Acidimicrobiaceae bacterium A6 were then grown in Microbial Electrolysis Cells (MECs). While being gently shaken, with a voltage input of 0.7V and a 10Ω resistance between the anode and cathode, the MECs produce currents, increasing from 0.1μA up to ~35μA while NH4+ was available in the medium. Up to 105 copies of DNA/ml have been detected in liquid medium after 3 weeks of operation. Hence, MECs represent an alternative, iron-free form, for optimized biomass production of pure Acidimicrobiaceae bacterium A6. References 1. Clement J.C., Shrestha J., Ehrenfeld J.G., Jaffé P.R., 2005. Soil Biol Biochem 37:2323-2328. 2. Huang S., and Jaffé P.R., 2014. Biogeosciences Discussions 11, 12295-12321 3. Shrestha J., Rich J., Ehrenfeld J., Jaffé P.R., 2009. Soil Sci. 174:156-164. 4. Yang W.H., Weber K.A., Silver W.L., 2012. Nat Geosc 5: 538-541. 5. Ding L.J., An X.L., Li S., Zhang G.L., Zhu Y.G., 2014. Environ Sci Technol. 48:10641-7

To What Extent Do Neighborhood Differences Mediate Racial Disparities in Participation After Spinal Cord Injury?

PubMed

Botticello, Amanda L; Boninger, Mike; Charlifue, Susan; Chen, Yuying; Fyffe, Denise; Heinemann, Allen; Hoffman, Jeanne M; Jette, Alan; Kalpakjian, Claire; Rohrbach, Tanya

2016-10-01

To examine the role of residential neighborhood characteristics in accounting for race disparities in participation among a large sample of community-living adults with chronic spinal cord injury (SCI). Secondary analysis of cross-sectional survey data from the national Spinal Cord Injury Model Systems (SCIMS) database linked with national survey and spatial data. SCIMS database participants enrolled at 10 collaborating centers active in follow-up between 2000 and 2014. The sample consisted of persons with SCI (N=6892) in 5441 Census tracts from 50 states and the District of Columbia. Not applicable. The Craig Handicap Assessment and Reporting Technique was used to measure full participation across 4 domains: physical independence, mobility, occupation, and social integration. Racial minority groups had lower odds of reporting full participation relative to whites across all domains, suggesting that blacks and Hispanics are at risk for poorer community reintegration after SCI. Neighborhood characteristics, notably differences in socioeconomic advantage, reduced race group differences in the odds of full occupational and social integration, suggesting that the race disparities in community reintegration after SCI are partially attributable to variation in the economic characteristics of the places where people live. This investigation suggests that addressing disadvantage at the neighborhood level may modify gaps in community participation after medical rehabilitation and provides further support for the role of the environment in the experience of disability. Copyright © 2016 American Congress of Rehabilitation Medicine. Published by Elsevier Inc. All rights reserved.

Thermodysregulation in persons with spinal cord injury: case series on use of the autonomic standards.

PubMed

Handrakis, John P; Trbovich, Michelle; Hagen, Ellen Merete; Price, Michael

2017-01-01

The ability to maintain core body temperature (Tcore) within a narrow range (37 ± 0.6 °C), despite exposure to a wide range of ambient temperatures, is essential in order to provide an optimal environment for vital organs, the central nervous system (CNS), and cellular processes to function. High-level (above T6) spinal cord injury (SCI) interrupts the autonomic nervous system's ability to carry out hypothalamic regulation of thermoregulatory mechanisms for both heat dissipation and conservation. This interruption leaves persons with high-level SCI vulnerable to hyper and hypothermia even during exposure to relatively mild ambient temperatures. The goal of the Autonomic Standards is to enable the clinician to quickly identify those individuals with SCI who may be most at risk for thermoregulatory dysfunction. Case 1: Heat Exhaustion, Case 2: Heat Stroke in absence of CNS symptoms, Case 3: Heat Exhaustion. The three cases demonstrate the signs and symptoms that may accompany hyperthermia in persons with SCI. The onset may be quite rapid and the condition persistent, despite ambient temperatures being much less intense than expected to be necessary to induce similar conditions in able-bodied (AB) persons. The responses of the persons in the case studies to the temperature regulation and autonomic control of sweating sections of the Autonomic Standards would identify them as being vulnerable and warrant providing appropriate exposure guidelines and precautions to them and their caregivers.

A Review of Theoretical Frameworks for Supply Chain Integration

NASA Astrophysics Data System (ADS)

Thoo, AC; Tan, LC; Sulaiman, Z.; Zakuan, N.

2017-06-01

In a world of fierce competition and business driven by speed to market, good quality and low costs, this environment requires firms to have a source of competitive advantage that is inimitable and non-substitutable. For a supply chain integration (SCI) strategy to achieve sustainable competitive advantage it must be non-substitutable, inimitable, path-dependent and developed over time. Also, an integrated supply chain framework is needed to tie the whole network together in order to reduce perennial supply chain challenges such as functional silos, poor transparency of knowledge and information and the inadequate formation of appropriate customer and supplier relationships. Therefore, this paper aims to evaluate the competitive impact of a SCI strategy on firm performance using the theory of Resource-based View (RBV) and relational view.

Amphibolite of the Xinghuadukou group from the Xinlin-Xiguitu belt, NE China: new evidence for the NE branch of the Paleo-Asian Ocean

NASA Astrophysics Data System (ADS)

Hou, Wenzhu

2017-04-01

The tectonic evolution of the Paleo-Asian Ocean (PAO) witnessed the cycling of two supercontinents, Rodinia and Pangea, in Earth's geological history. This long-lasting paleo-ocean was initiated by the breakup of the supercontinent Rodinia during the Early Neoproterozoic (1,2) and terminated by the final collage of the supercontinent Pangea from Central to Eastern (current coordinates) Asia, likely lasting to the Late Permian or Early Triassic (3,4). Numerous continental and island arcs, seamounts, mid-ocean ridges and micro-blocks were amalgamated responding to the subduction and consumption of the oceanic crust of the PAO, to form the most complex and long-living Phanerozoic accretionary orogenic belt, the Central Asian Orogenic Belt (CAOB) (5,6). Trapped by the collision and amalgamation of the eastern segment of CAOB, several rock suites of oceanic affinity were reported along the Xinlin-Xiguitu belt that connects the Erguna block to the northwest and the Xing'an block to the southeast in NE China, including the Toudaoqiao blueschist (7), Jifeng ophiolite (although the forming environment remains debatable, see 8 and 9), and Xinlin ophiolite (10,11). All these suites have been proposed to be the relics of the NE branch of the PAO. However, along the northeastern extension of this belt, outcropped the Xinghuadukou group that was previously thought Paleoproterozoic in age yet has been reconsidered to be Cambrian (12), the relationship of which and this belt remains unclear. In this study, a suite of amphibolite was collected from the Xinghuadukou group outcropped in the easternmost Xinlin-Xiguitu belt in NE China and conducted geochemical analysis to discuss their forming environment and tectonic implications. Samples display low SiO2 (45%-49%wt), low K2O (0.55%-1.07%wt) compositions, low in A/CNK, but high in A/NK and FeOt/MgO ratios. REE compositions are relative low (ΣREE=52-122ppm) showing a flat chondrite normative pattern with slight enrichment in LREE ((La/Ya)N=1.5-2.4) and no Eu anomaly (Eu/Eu*=0.9-1.0). The LILE fractionation is indistinctive ((Sr/Y)N=1.1-1.8). Samples show an evident E-MORB affinity. Along with the previous studies, it can be concluded: 1) the protolith of the amphibolite of the Xinghuadukou group is a suite of tholeiitic basalt that formed in the oceanic islands environment; 2) with all the oceanic suites reported in Xinlin-Xiguitu belt, a branch of the Eastern PAO can be well defined, which likely existed from the Late Neoproterozoic to Late Cambrian, so called the Xinlin-Xiguitu Ocean. Acknowledgements: This study was financially supported by the National Natural Science Foundation of China (Projects 41190075, 41190070, 41230207, 41390441), the Hong Kong Research Grants Council General Research Fund (HKU7063/13P and 17301915), and the HKU Seed Funding Programme for Basic Research (201311159126). References: 1. N. L. Dobretsov et al., Gondwana Res. 6(2), 143-159 (2003). 2. J. Tang et al., Precambrian Res. 224, 597-611 (2013). 3. J. Y. Li, J. Asian Earth Sci. 26(3), 207-224 (2006). 4. P. R. Eizenhöfer et al., Tectonics 33(4), 441-463 (2014). 5. B. F. Windley et al., J. Geol. Soc. 164(1), 31-47 (2007). 6. W. Xiao et al., Annu. Rev. Earth Planet. Sci. 43, 477-507 (2015). 7. J. B. Zhou et al., J. Asian Earth Sci. 97, 197-210 (2015). 8. Z. Feng et al., Int. J. Earth Sci. 105(2), 491-505 (2016). 9. D. H. Ni, Int. J. Earth Sci. (2016). doi:10.1007/s00531-016-1412-2 10. R. S. Li, Heilongjiang Geology, 2(1), 21-32 (1991). 11. W. Yan et al., Earth Sci. - J. Chin. Uni. Geo. 8 (2014). 12. L. Miao et al., Chin. Sci. Bull. 52(8), 1112-1124 (2007).

The Implementation Challenge and the Learning Health System for SCI Initiative.

PubMed

Stucki, Gerold; Bickenbach, Jerome

2017-02-01

The paper introduces the special issue by linking the International Spinal Cord Injury (InSCI) Community Survey study to the Learning Health System for SCI Initiative (LHS-SCI). The LHS-SCI was designed to respond to the implementation challenge of bringing about policy reform in light of the targeted policy recommendations of World Health Organization's International Perspectives on SCI report as well as the call for action of WHO's Global Disability Action Plan. The paper reviews the components of LHS-SCI relevant to internationally comparable information, a theory of change to guide for action, and the tools for evidence-informed policy. The interplay between persons, their health needs, and the societal response to those needs provides the foundation for the organization of the LHS-SCI Initiative. Moreover, as the other articles in this special issue describe in detail, the rationale, conceptualization, and study design of the InSCI study are also informed by the rationale, and mission, of the LHS for SCI Initiative. The LHS-SCI, and the implementation challenge that motivates it, is responsible for the design of the InSCI study and the overall mission of LHS-SCI to continuously improve the lived experience of people living with SCI around the world through an international evidence- and rights-informed research and policy reform effort.

Knowledge acquisition and decision-making: spinal cord injured individuals perceptions of caring during rehabilitation.

PubMed

Lucke, K T

1997-09-01

Nurses and other healthcare providers have little research to guide them on specific interventions and attitudes which expedite the attainment of rehabilitation outcomes by spinal cord injured (SCI) individuals and their successful return to the community (Fuhrer, 1994; Whiteneck, 1994). Acquisition of knowledge is required during rehabilitation to learn self-care and decision-making which is essential to long term survival following SCI. However, skills that patients and families are able to accomplish in rehabilitation are often not able to be translated into the home environment (White & Holloway, 1990). The process of learning self-care and decision-making needs to be more clearly elucidated, so more effective interventions can be designed which can improve problem-solving and lead to enhanced well-being and quality of life. The purpose of this qualitative study was to describe the meaning, process and consequences of caring during rehabilitation from the perspective of the SCI individual. This paper will report on the findings from one research question: How is the process of a developing caring relationship perceived by SCI individuals during rehabilitation? The theoretical foundation of caring for this study was synthesized from philosophical, ethical, feminist, and nursing literature. A purposive sample of adults with traumatic SCI were interviewed at least once during their initial rehabilitation stay. Twenty interviews were conducted with fifteen participants at various times during their rehabilitation stay over a six month period. The core category of "getting back together" or reintegration of self, which was the major work of rehabilitation, was accomplished with nurses and therapists who were perceived as caring. The process of a developing caring relationship was conceptualized, from participants' descriptions in three phases: learning the other, learning what I need to know, and letting me find out. During each phase reciprocal behaviors occurred between the patient and the caregiver resulting in intermediate outcomes, which facilitated movement to the next phase. Consequences of these caring relationships were: well-being, self-care, autonomy, independence, and hope. Caring by rehabilitation professionals was perceived by SCI individuals as central to recovery and to a positive attitude toward disability.

EDITORIAL: Announcing the 2009 Measurement Science and Technology Outstanding Paper Awards Announcing the 2009 Measurement Science and Technology Outstanding Paper Awards

NASA Astrophysics Data System (ADS)

Foss, John; Dewhurst, Richard; Fujii, Kenichi; Regtien, Paul

2010-06-01

Since 1991, Measurement Science and Technology has awarded a Best Paper prize. The Editorial Board of this journal believes that such a prize is an opportunity to thank authors for submitting their work, and serves as an integral part of the on-going quality review of the journal. The current breadth of topical areas that are covered by MST has made it advisable to expand the recognition of excellent publications. Hence, since 2005 the Editorial Board have presented 'Outstanding Paper Awards' in four subject categories: Fluid Mechanics; Measurement Science; Precision Measurements; and Sensors and Sensing Systems. This year also saw the introduction of a new category—Optical and Laser-based Techniques. 2009 Award Winners—Fluid Mechanics Digital particle image velocimetry (DPIV) robust phase correlation Adric Eckstein and Pavlos P Vlachos Department of Mechanical Engineering, Virginia Tech, Blacksburg, VA, USA This paper [1] represents a valuable improvement to the phase-only correlation technique (first proposed by Wernet in this journal in 2005 (Wernet M 2005 Symmetric phase-only filtering: a new paradigm for DPIV data processing Meas. Sci. Technol. 16 601-18) for particle-image-velocimetry (PIV) measurements of fluid flow. The authors establish a sound theoretical foundation and clearly describe the working principle of their robust phase correlation method. The methodology for assessing performance is excellent. Detailed results on several internationally recognized PIV test cases are presented. The robust phase correlation method is of general applicability and therefore can be expected to have substantial impact in this very active area of fluid-mechanics measurements. 2009 Award Winner—Precision Measurement A nanonewton force facility and a novel method for measurements of the air and vacuum permittivity at zero frequencies V Nesterov Physikalisch-Technische Bundesanstalt (PTB), Bundesallee 100, D-38116 Braunschweig, Germany This paper [2] describes a new method for measuring the air and vacuum permittivity by observing a nanonewton force in a disk-pendulum. The frequency dependence of the vacuum permittivity, ɛ0, has been one of the fundamental questions in physics. Although it is confidently believed that there is no frequency dependence in ɛ0, very few experiments have been conducted to verify the properties of ɛ0. Especially in the region near zero frequencies, no experiment has been done in the vacuum. The precise measurement of the vacuum permittivity is therefore of fundamental interest to test the correctness of Maxwell's equations in an electrostatic field. In this paper, the author developed a new principle using a disk-pendulum, where the displacement of the disk-pendulum in the presence of an electrostatic field has been detected by optical interferometry. The nanonewton forces generated by the electrostatic field have been measured to evaluate the air and vacuum permittivity at zero frequencies, achieving a relative standard uncertainty of 10-5 in the measurement of ɛ0. The measurement system developed here also opened a new way for the force standard in the nanonewton region, investigation of the Casimir effect, direct measurement of laser power etc. This paper has been downloaded more than 200 times since its publication. The selection committee members on precision measurement selected this paper from a strongly competitive list of eleven candidates for its sophisticated idea, originality in apparatus, and excellent result with uncertainty evaluation. Considering its impact on fundamental physics and also on precision force measurement in the nanonewton region, the paper was nominated for the MST Precision Measurement Award from the papers published in 2009. 2009 Award Winners—Sensors and Sensing Systems High-resolution and compact refractometer for salinity measurements D Malardé, Z Y Wu, P Grosso, J-L de Bougrenet de la Tocnaye and M Le Menn Optics Department, UMR CNRS 6082 FOTON, TELECOM Bretagne, CS 83818, 29238 Brest Cédex 3, France Laboratoire de Métrologie et de Chimie Océanographique, SHOM 13 rue du Châtelier, BP 30316, 29603 Brest Cedex, France The absolute salinity of seawater is an important component in the determination of the ocean's thermodynamic properties. This paper [3] presents a measurement system for very accurate determination of the salinity. The method is based on measuring the refractive index of seawater, a parameter that is related to the salinity. Although the method is essentially simple: using a prism and a PSD for direct measurement of the angle of refraction, the refraction also depends on many more parameters (temperature, pressure, wavelength). Moreover, for obtaining accurate salinity values, a high resolution of the refractive index is required, of the order of 10-7, under all possible conditions. Starting with a list of notations and symbols, the paper follows with an overview of existing methods for salinity measurements and their performances. Next, the principle based on refractometry is introduced, and a theoretical model is presented, comprising a large number of parameters that influence the properties of the refractometer. From this analysis there follows an optimization of the geometry of the device. The sensitivity for salinity and other water parameters are estimated from theory, and verified experimentally. Salinity measurements are compared with those using standard salinometers, and show an uncertainty less than a few 10-3 psu (practical salinity units). The obtained resolution is about 4 × 10-7, which is limited by that of the readout electronics of the PSD. It is demonstrated that this can be further improved to achieve the required resolution lower than 10-7. The authors make clear that their prototype, the length of which is about 12 cm, is an important step to a fully in situ oceanographic salinometer, but further testing is required to confirm reliability. Indeed, the paper does not report on long term effects of, for instance, contamination of the optical parts. Hopefully this will be investigated and published in the next stage of the research. 2009 Award Winners—Measurement Science Analysis and mitigation of measurement uncertainties in the traceability chain for the calibration of photovoltaic devices Harald Mullejans, Willem Zaaiman and Roberto Galleano European Commission, Joint Research Centre, Institute for Energy, Renewable Energy Unit, European Solar Test Installation, Via E Fermi 2749, I-21027 Ispra (Va), Italy The energy output and efficiency from different types of photovoltaic (PV) devices is an essential characteristic of photovoltaics. They may only be assessed from cell performance under standard test conditions, with traceability back to international standards. As this paper [4] points out in its introduction, the reliability of the measurements and their uncertainty are of crucial importance to manufacturers, operators and investors. Several features in the format of the article help to make this an excellent paper. Following an informative abstract, the paper has a concise introduction followed by a detailed formulation of the problem to be addressed. After a discussion of present-day international codes related to the measurement and performance of PVs, the paper goes on to describe one of the most difficult issues in traceability, that of deriving an irradiance quantity which is normally measured by a reference PV device. This might appear straightforward, but the paper highlights the difficulties of measuring the irradiance of sunlight (either simulated or natural) during the evaluation of the electrical performance of PV devices. The calibration of any PV device essentially consists of the measurement of the IV characteristics, by sweeping the device from its short-circuit condition (SC) to its open-circuit condition (OC) when exposed to (pulsed or continuous) simulated or natural sunlight. In this paper, all measurements were carried out at the European Solar Test Installation at Ispra in Italy. After describing the measurement methods, the authors discuss at length the calculations of measurement uncertainty. This leads to a rigorous discussion of relative uncertainties from measurement parameters. Uncertainties arise from a range of parameters that include small contributions from electrical, temperature and fill factor parameters. But the greatest arises from uncertainties both in the optical source and in the reference cell. As a consequence, the authors make a convincing case both for identifying the sources of uncertainty and for reducing overall uncertainties from +/-2.6% to below +/-2%. The conclusions are concise, and the paper is rounded off with a list of 34 references with several papers cited from 2005 onwards. This paper was rated as excellent by external referees, and has been downloaded several hundred times since its publication. It is one of 30 papers nominated this year in the Measurement Science category, and gained most votes from those short-listed. The discussion on measurement uncertainty sets a fine example to all researchers involved in experimental measurement science. 2009 Award Winners—Optical and Laser-based Techniques Measurement of tiny droplets using a newly developed optical fibre probe micro-fabricated by a femtosecond pulse laser T Saito, K Matsuda, Y Ozawa, S Oishi and S Aoshima Shizuoka University, 3-5-1 Johoku, Naka-ku Hamamatsu, Shizuoka 432-8561, Japan CRL, Hamamatsu Photonics K.K., 5000 Hirakuchi, Hamakita-ku Hamamatsu, Shizuoka 434-8601, Japan This Award goes to a paper [5] describing a fascinating and novel optical fibre probe applied to measurements in gas-liquid two-phase flows. Optical probes have already been widely applied to two-phase flows. These include the use of four-tip optical probes (F-TOP) for millimetre-size bubbles/droplets, and a single-tip optical fibre probe (S-TOP) for sub-millimetre size bubbles/droplets. This new paper describes how micro-machining a groove into the side of the silica fibre using a femtosecond laser system leads to a new optical fibre probe (Fs-TOP). It is capable of measurements of velocity and size of droplets down to about 50 µm in diameter. A useful introduction describes the importance of characterization required in gas-liquid two-phase flows. Measurements are required in a variety of research fields, e.g. sprays, automotive engines, fine chemistry and atomic power plants. Characterization of bubbles/droplets at high density has been desired for both laboratory and industrial use. Addressed towards this goal, this paper describes the use of optical fibre probes that have been modified with a side-wall groove. The authors point out that whereas the S-TOP is made very easily, with the tip of the S-TOP only micro-ground into a wedge shape, the Fs-TOP is very difficult to fabricate. In addition to a wedge tip, fabrication involves a femtosecond laser system with nano-order six-axis automatic optical stages and confocal optics. Hence it is important to intelligently select between these two types of probe depending on the measurement objective. Moreover, like all types of new probe, it is first necessary to validate its performance against other probes with accepted performance characteristics. After describing the experimental arrangement, the authors discuss at length the performance of the new Fs-TOP and that of the S-TOP for comparison. Additionally, results from the Fs-TOP are compared with those from visualization of the droplets by a high-speed video camera. Results show satisfactory agreement. After a lengthy presentation of results and discussion, the authors produce a concise set of inclusions, including a summary of the small perturbation in droplet size arising from the presence of the probe. The paper was one of 22 papers nominated this year for the Best Paper Award in Optical and Laser-based Techniques. It crosses the disciplines of optical measurement science and measurements required for the characterization of two-phase fluid flow. Exploiting new technological facilities in micromachining, the paper is an excellent example of new opportunities that may arise in measurement. References [1] Eckstein A and Vlachos P P 2009 Digital particle image velocimetry (DPIV) robust phase correlation Meas. Sci. Technol. 20 055401 (14pp) [2] Nesterov V 2009 A nanonewton force facility and a novel method for measurements of the air and vacuum permittivity at zero frequencies Meas. Sci. Technol. 20 084012 (6pp) [3] Malardé D, Wu Z Y, Grosso P, de Bougrenet de la Tocnaye J-L and Le Menn M 2009 High-resolution and compact refractometer for salinity measurements Meas. Sci. Technol. 20 015204 (8pp) [4] Müllejans H, Zaaiman W and Galleano R 2009 Analysis and mitigation of measurement uncertainties in the traceability chain for the calibration of photovoltaic devices Meas. Sci. Technol. 20 075101 (12pp) [5] Saito T, Matsuda K, Ozawa Y, Oishi S and Aoshima S 2009 Measurement of tiny droplets using a newly developed optical fibre probe micro-fabricated by a femtosecond pulse laser Meas. Sci. Technol. 20 114002 (12pp)

SciFlo: Semantically-Enabled Grid Workflow for Collaborative Science

NASA Astrophysics Data System (ADS)

Yunck, T.; Wilson, B. D.; Raskin, R.; Manipon, G.

2005-12-01

SciFlo is a system for Scientific Knowledge Creation on the Grid using a Semantically-Enabled Dataflow Execution Environment. SciFlo leverages Simple Object Access Protocol (SOAP) Web Services and the Grid Computing standards (WS-* standards and the Globus Alliance toolkits), and enables scientists to do multi-instrument Earth Science by assembling reusable SOAP Services, native executables, local command-line scripts, and python codes into a distributed computing flow (a graph of operators). SciFlo's XML dataflow documents can be a mixture of concrete operators (fully bound operations) and abstract template operators (late binding via semantic lookup). All data objects and operators can be both simply typed (simple and complex types in XML schema) and semantically typed using controlled vocabularies (linked to OWL ontologies such as SWEET). By exploiting ontology-enhanced search and inference, one can discover (and automatically invoke) Web Services and operators that have been semantically labeled as performing the desired transformation, and adapt a particular invocation to the proper interface (number, types, and meaning of inputs and outputs). The SciFlo client & server engines optimize the execution of such distributed data flows and allow the user to transparently find and use datasets and operators without worrying about the actual location of the Grid resources. The scientist injects a distributed computation into the Grid by simply filling out an HTML form or directly authoring the underlying XML dataflow document, and results are returned directly to the scientist's desktop. A Visual Programming tool is also being developed, but it is not required. Once an analysis has been specified for a granule or day of data, it can be easily repeated with different control parameters and over months or years of data. SciFlo uses and preserves semantics, and also generates and infers new semantic annotations. Specifically, the SciFlo engine uses semantic metadata to understand (infer) what it is doing and potentially improve the data flow; preserves semantics by saving links to the semantics of (metadata describing) the input datasets, related datasets, and the data transformations (algorithms) used to generate downstream products; generates new metadata by allowing the user to add semantic annotations to the generated data products (or simply accept automatically generated provenance annotations); and infers new semantic metadata by understanding and applying logic to the semantics of the data and the transformations performed. Much ontology development still needs to be done but, nevertheless, SciFlo documents provide a substrate for using and preserving more semantics as ontologies develop. We will give a live demonstration of the growing SciFlo network using an example dataflow in which atmospheric temperature and water vapor profiles from three Earth Observing System (EOS) instruments are retrieved using SOAP (geo-location query & data access) services, co-registered, and visually & statistically compared on demand (see http://sciflo.jpl.nasa.gov for more information).

Environmental factors and their role in participation and life satisfaction after spinal cord injury.

PubMed

Whiteneck, Gale; Meade, Michelle A; Dijkers, Marcel; Tate, Denise G; Bushnik, Tamara; Forchheimer, Martin B

2004-11-01

To investigate environmental barriers reported by people with spinal cord injury (SCI), and to determine the relative impact of environmental barriers compared with demographic and injury characteristics and activity limitations in predicting variation in participation and life satisfaction. Cross-sectional, follow-up survey. Individuals rehabilitated at 16 federally designated Model Spinal Cord Injury Systems of care, now living in the community. People with SCI (N=2726) who completed routine follow-up research interviews between 2000 and 2002. Not applicable. The Craig Hospital Inventory of Environmental Factors-Short Form (CHIEF-SF), the Craig Handicap Assessment and Reporting Technique-Short Form, and the Satisfaction With Life Scale. The top 5 environmental barriers reported by subjects with SCI, in descending order of importance, were the natural environment, transportation, need for help in the home, availability of health care, and governmental policies. The CHIEF-SF subscales accounted for only 4% or less of the variation in participation; they accounted for 10% of the variation in life satisfaction. The inclusion of environmental factors in models of disability was supported, but were found to be more strongly related to life satisfaction than to societal participation.

Photoenhanced uptakes of NO2 by indoor surfaces: A new HONO source

NASA Astrophysics Data System (ADS)

Gligorovski, S.; Bartolomei, V.; Soergel, M.; Gomez Alvarez, E.; Zetzsch, C.; Wortham, H.

2012-12-01

Nitrous acid (HONO) is a known household pollutant that can lead to human respiratory tract irritation. HONO acts as the nitrosating agent, e.g. by the formation of the so-called third-hand smoke after wall reactions of HONO with nicotine (1). HONO can be generated indoors directly during combustion processes or indirectly via heterogeneous NO2 reactions with adsorbed water on diverse surfaces (2). Recently a new source was identified as another path of HONO formation in the troposphere (3). Namely, the light-induced heterogeneous reaction of NO2 with adsorbed organics (known as photosensitizers) on various surfaces such as roads, buildings, rocks or plants leads to enhanced HONO production. The detected values of HONO indoors vary in the range between 2 and 25 parts per billion (ppb). However, like outdoors, the processes leading to HONO formation indoors are not completely understood (4). Indoor photolysis radiation sources include exterior sunlight (λ>350 nm) that enters typically through the windows and indoor illumination sources, i.e., rare gas/mercury fluorescent light bulbs and tungsten and tungsten/halogen light bulbs among others. The present work is showing the importance of indoor sources of HONO recently identified or postulated. We have tested a number of common household chemical agents commonly used for cleaning purposes or coatings of domestic surfaces to better identify different indoor HONO sources. We used a heterogeneous flow tube technique to test the HONO production potentials of these household chemical agents under different experimental conditions, namely with and without light and at different relative humidity levels and different NO2 concentrations. We report uptake kinetics measurements of the heterogeneous reaction of gas phase NO2 with lacquer and paint coated on the walls of the reactor. The flow tube was irradiated with four near-ultraviolet (UV) emitting lamps (range of wavelengths 300-420nm). We observed that the heterogeneous conversion of NO2 to HONO on lacquer surfaces and on white wall paints is substantially enhanced in the presence of light and at higher relative humidity (RH = 60%). In runs carried out applying experimental conditions typically found indoors, i.e., NO2 mixing ratios of 25 ppb and 60% RH%, the observed NO2 uptakes on a surface coated with lacquer and paint showed an enhancement of one order of magnitude in the presence of light as compared to the uptake observed in the dark. Our results indicate, contrary to other study that claimed that humidity does not influence the NO2 reactions with adsorbed organics, that actually both postulated HONO sources combined i.e. heterogeneous NO2 reactions with adsorbed organics (photosensitizers) in presence of elevated humidity leads to even more pronounced HONO production. Reference: 1. M., Sleiman, L. A., Gundel, J. F., Pankow, P., Jacob, B. C., Singer, H., Destaillats, P. Natl. Acad. Sci. USA, 107, 6576 (2010). 2. B. J. Finlayson-Pitts, L. M. Wingen, A. L. Sumner, D. Syomin, K. A. Ramazan, Phys. Chem. Chem. Phys. 5, 223 (2003). 3. K., Stemmler, M., Ammann, C., Donders, J., Kleffmann, C., George, Nature 440, 195 (2006). 4. E. Gomez Alvarez, H. Wortham, R. Strekowski, C. Zetzsch, S. Gligorovski, Environ. Sci. Technol., 46, 1955 (2012).

The Development of a Self-Regulation in a Collaborative Context Scale

ERIC Educational Resources Information Center

Law, Victor; Ge, Xun; Eseryel, Deniz

2016-01-01

Self-regulation has been shown as a critical factor in learning in a regular classroom environment (e.g. Wolters and Pintrich in "Instr Sci" 26(1):27-47, 1998. doi: 10.1023/A:1003035929216). However, little research has been conducted to understand self-regulation in the context of collaboration (Dinsmore et al. in "Educ Psychol…

Spacecraft Charging - Present Situation and Some Problems

DTIC Science & Technology

2007-06-01

Individual Cosmic Dust Grains," Astrophys J., vol. 645, part 1,324-336, 2006."IS Abbas, M.M., D. Tankosic, P.D. Craven, J.F. Spann, A. LeClair and E.A...Garrett, H.B. and A.R. Hoffman , "Comparison of Spacecraft Charging Environments at the Earth, Jupiter, and Saturn,"IEEE Trans. Plasma Sci., vol.28, no

Exploring Pupils' Beliefs about Designers and Designing

ERIC Educational Resources Information Center

Trebell, Donna

2011-01-01

The purpose of this paper is to report on an investigation into pupil beliefs about designers and designing conducted as part of a research project focusing on Designerly Activity in Secondary Design and Technology which builds upon a pilot study (Barlex and Trebell in "Int J Technol Design Educ," 2007). Four research questions drove this element…

New National Cryo-EM Facility Provides Access to Cutting-Edge Technology for Cancer Research Community | Frederick National Laboratory for Cancer Research

Cancer.gov

Cancer researchers nationwide now have access to the latest technology in the field of cryo-electron microscopy (cryo-EM)—the study of protein structures at atomic resolution—at the Frederick National Lab for Cancer Research. The emerging technol

Effect of Ocean Interannual Variability on Acoustic Propagation in the Philippine Sea and South China Sea

DTIC Science & Technology

2017-06-01

Coronas , 1920). The dominant pattern of interannual variability is the El Nino Southern Oscillation (ENSO), which has two quasi-periodic states...Validation of Wavewatch-III using TOPEX/ Poseidon data. J. Atmos. Oceanic Technol., 21, 1718–1733. Coronas , J., 1920: The climate and weather of the

IEA/Annex II Powder Characterization Cooperative Program

DTIC Science & Technology

1989-06-01

entatie Sampling of Particks with a Spinning Riffler. Stochastic ModeL Powder Technol., v. 19, 1978. p. 227-233 6. CHARLIER, R., and GOOSSENS , P. J. D...12222 St. Paul, Mix 55144 1 ATTN: Prof. W. A. Lanfo d ATTN: R. E. Richards State University of New York at Stony Brook, Department of Technology

Fundamental Properteries and Capabilities of Plasmonic Antennas for Efficient Interaction with Nanoeletronics

DTIC Science & Technology

2015-08-20

the THz region. Microwave Opt. Technol. Lett. 48, 524-529 (2006). 57. Huo, Y., Taylor, G. W. & Bansal , R. Planar log-periodic antennas on extended...Berry, M. R. Hashemi and M. Jarrahi, Appl. Phys. Lett. 14, 081122, 2014. [39] Y. Huo, G. W. Taylor and R. Bansal , J. Infrared, Millimeter and

Increasing specialty care access through use of an innovative home telehealth-based spinal cord injury disease management protocol (SCI DMP)

PubMed Central

Seton, Jacinta M.; Washington, Monique; Tomlinson, Suk C.; Phrasavath, Douangmala; Farrell, Karen R.; Goldstein, Barry

2016-01-01

Background A spinal cord injury disease management protocol (SCI DMP) was developed to address the unique medical, physical, functional, and psychosocial needs of those living with spinal cord injuries and disorders (SCI/D). The SCI DMP was piloted to evaluate DMP clinical content and to identify issues for broader implementation across the Veterans Affairs (VA) SCI System of Care. Methods Thirty-three patients with SCI/D from four VA SCI centers participated in a 6-month pilot. Patients received customized SCI DMP questions through a data messaging device (DMD). Nurse home telehealth care coordinators (HTCC) monitored responses and addressed clinical alerts daily. One site administered the Duke Severity of Illness (DUSOI) Checklist and Short Form-8 (SF-8™) to evaluate the changes in comorbidity severity and health-related quality of life while on the SCI DMP. Results Patients remained enrolled an average of 116 days, with a mean response rate of 56%. The average distance between patient's home and their VA SCI center was 59 miles. Feedback on SCI DMP content and the DMD included requests for additional clinical topics, changes in administration frequency, and adapting the DMD for functional impairments. Improvement in clinical outcomes was seen in a subset of patients enrolled on the SCI DMP. Conclusion SCI HTCCs and patients reported that the program was most beneficial for newly injured patients recently discharged from acute rehabilitation that live far from specialty SCI care facilities. SCI DMP content changes and broader implementation strategies are currently being evaluated based on lessons learned from the pilot. PMID:24617497

Increasing specialty care access through use of an innovative home telehealth-based spinal cord injury disease management protocol (SCI DMP).

PubMed

Woo, Christine; Seton, Jacinta M; Washington, Monique; Tomlinson, Suk C; Phrasavath, Douangmala; Farrell, Karen R; Goldstein, Barry

2016-01-01

A spinal cord injury disease management protocol (SCI DMP) was developed to address the unique medical, physical, functional, and psychosocial needs of those living with spinal cord injuries and disorders (SCI/D). The SCI DMP was piloted to evaluate DMP clinical content and to identify issues for broader implementation across the Veterans Affairs (VA) SCI System of Care. Thirty-three patients with SCI/D from four VA SCI centers participated in a 6-month pilot. Patients received customized SCI DMP questions through a data messaging device (DMD). Nurse home telehealth care coordinators (HTCC) monitored responses and addressed clinical alerts daily. One site administered the Duke Severity of Illness (DUSOI) Checklist and Short Form-8 (SF-8™) to evaluate the changes in comorbidity severity and health-related quality of life while on the SCI DMP. Patients remained enrolled an average of 116 days, with a mean response rate of 56%. The average distance between patient's home and their VA SCI center was 59 miles. Feedback on SCI DMP content and the DMD included requests for additional clinical topics, changes in administration frequency, and adapting the DMD for functional impairments. Improvement in clinical outcomes was seen in a subset of patients enrolled on the SCI DMP. SCI HTCCs and patients reported that the program was most beneficial for newly injured patients recently discharged from acute rehabilitation that live far from specialty SCI care facilities. SCI DMP content changes and broader implementation strategies are currently being evaluated based on lessons learned from the pilot.

Psychometric evaluation of the Spanish version of the MPI-SCI.

PubMed

Soler, M D; Cruz-Almeida, Y; Saurí, J; Widerström-Noga, E G

2013-07-01

Postal surveys. To confirm the factor structure of the Spanish version of the MPI-SCI (MPI-SCI-S, Multidimensional Pain Inventory in the SCI population) and to test its internal consistency and construct validity in a Spanish population. Guttmann Institute, Barcelona, Spain. The MPI-SCI-S along with Spanish measures of pain intensity (Numerical Rating Scale), pain interference (Brief Pain Inventory), functional independence (Functional Independence Measure), depression (Beck Depression Inventory), locus of control (Multidimensional health Locus of Control), support (Functional Social Support Questionnaire (Duke-UNC)), psychological well-being (Psychological Global Well-Being Index) and demographic/injury characteristics were assessed in persons with spinal cord injury (SCI) and chronic pain (n=126). Confirmatory factor analysis suggested an adequate factor structure for the MPI-SCI-S. The internal consistency of the MPI-SCI-S subscales ranged from acceptable (r=0.66, Life Control) to excellent (r=0.94, Life Interference). All MPI-SCI-S subscales showed adequate construct validity, with the exception of the Negative and Solicitous Responses subscales. The Spanish version of the MPI-SCI is adequate for evaluating chronic pain impact following SCI in a Spanish-speaking population. Future studies should include additional measures of pain-related support in the Spanish-speaking SCI population.

Infertility in Men with Spinal Cord Injury: Research and Treatment

PubMed Central

Brackett, Nancy L.

2012-01-01

Spinal cord injury (SCI) occurs most often to young men. Following SCI, most men are infertile due to a combination of erectile dysfunction, ejaculatory dysfunction and semen abnormalities. Erectile dysfunction may be treated by the same therapies that are used in the general population. Similarly, the same treatments that are effective to assist conception in couples with non-SCI male factor patients are effective in assisting conception in SCI male-factor patients. The most apparent differences in male-factor symptoms between SCI and non-SCI patients are the high occurrences of anejaculation and atypical semen profiles in men with SCI. Methods available to assist ejaculation in men with SCI include penile vibratory stimulation and EEJ. Use of surgical sperm retrieval as the first line of treatment for anejaculation in men with SCI is controversial. Most men with SCI have a unique semen profile characterized by normal sperm concentration, but abnormally low sperm motility. Toxic substances in the semen contribute to this problem. Despite impaired sperm parameters, pregnancy outcomes using sperm from men with SCI are similar to pregnancy outcomes using sperm from non-SCI men. Future studies should focus on improving natural ejaculation and improving semen quality in these men. PMID:24278717

Prevalence and Etiology of Hypogonadism in Young Men With Chronic Spinal Cord Injury: A Cross-Sectional Analysis From Two University-Based Rehabilitation Centers.

PubMed

Sullivan, Shannon D; Nash, Mark S; Tefera, Eshetu; Tinsley, Emily; Blackman, Marc R; Groah, Suzanne

2017-08-01

Spinal cord injury (SCI) triggers an "accelerated aging" process that may include development of hypogonadism, even among younger men with SCI; however, few studies have investigated the prevalence or etiology of hypogonadism in men with SCI. Young men with SCI also are at increased risk for developing metabolic dysfunction after injury, which may be exacerbated by concomitant testosterone (T) deficiency, thus identifying the prevalence and risk factors for T deficiency in men with SCI is important for their long-term health. To investigate the prevalence, risk factors, and etiology of T deficiency (hypogonadism) in otherwise-healthy men with chronic, motor complete SCI. Secondary cross-sectional analysis. Rehabilitation research centers in Washington, DC, and Miami, Florida. Men (n = 58) aged 18-45 years with chronic (≥1 year), motor complete SCI without comorbidities or use of testosterone therapy. Plasma concentrations of hormones were measured with standardized assays. Body composition was assessed with dual-energy x-ray absorptiometry scan. Serum total T and calculated free T. T deficiency was more common in men after SCI than in a matched cohort of similarly-aged men without SCI (25%, SCI versus 6.7%, non-SCI, P < .001). The risk of hypogonadism appeared to be increased in men with more extensive injury and with higher percent body fat. The majority of men with SCI with low T had low serum LH levels, suggesting that central suppression of the hypothalamic-pituitary-gonadal axis may be the most common etiology of hypogonadism after SCI. Hypogonadism is more common in young men with SCI than in similarly aged men without SCI, suggesting that SCI should be identified as a risk factor for T deficiency and that routine screening for hypogonadism should be performed in the SCI population. II. Copyright © 2017 American Academy of Physical Medicine and Rehabilitation. Published by Elsevier Inc. All rights reserved.

Bacteria mediated dissolution of pyromorphite Pb5(PO4)3Cl in presence of Pseudomonas putida bacteria - an effect on Pb remobilization in the environment

NASA Astrophysics Data System (ADS)

Flis, Justyna; Manecki, Maciej; Merkel, Broder J.; Latowski, Dariusz

2010-05-01

The objective of the study was to determine the mechanisms of microbially enhanced dissolution of lead phosphate-pyromorphite Pb5(PO4)3Cl). Contrary to the current literature, the results of our experiments indicate a great potential for Pb remobilization in the environment by an aerobic microorganism acquiring phosphates. Broad knowledge exists about the role of Pb-apatites in regulating the behavior and the bioavailability of Pb in soils and wastewater. In situ Pb immobilization is one of the methods now routinely applied for the reclamation of Pb-contaminated soils, including shallow unconfined aquifers (Magalhaes & Silva, 2003; Magalhaes, 2002; Ma et al. 1993). This method is based on the principle that aqueous phosphates added to soil pore solutions form a very stable (insoluble) mineral pyromorphite (Pb-apatite) Pb5(PO4)3Cl. Bioavailability of aqueous Pb is thus minimized due to the very low solubility and the high thermodynamic stability of pyromorphite (Flis, 2007; Nriagu, 1974). Several reports have examined the ability of different bacterial species including Pseudomonas to solubilise insoluble inorganic phosphate compounds for example apatites (Welch et al., 2002; Maurice et al., 1999; Rodriguez and Fraga, 1999 ). Various species of Pseudomonas genera are encountered as common inhabitants of soils and wastes in the industrial areas under strong pollution influence. To date, there has not been any published evidence of microbial dissolution of pyromorphite. The major objective of the project was to study Pseudomonas putida growth in the presence of Pb-apatite (Pb5(PO4)3Cl) as the sole source of phosphate. It was to test the hypothesis that in the phosphate deficient environment bacteria are able to actively scavenge for P from the Pb-apatite which results in remobilization of Pb in the environment. The bacteria growth was investigated at 22oC. Commercially available Pseudomonas putida strain was used throughout. The experiment and its controls were run in standard growth medium for the period of 10 days, at starting pH=6.5. Samples were periodically analysed for pH, bacterial density, Pb and P (UV-vis, ICP). Our results indicate that Pb may be mobilized from pyromorphite by microbial activity, both in phosphorous-rich and phosphorous-deficient environment. At the experimental conditions the presence of bacteria enhances the dissolution of pyromorphite, resulting in up to 20 times increase of Pbaq. The observed effects of microorganisms on Pb remobilization need to be considered in Pb remediation strategies that rely on pyromorphite formation. References: FLIS J.M., (2007). "Thermodynamic properties of minerals from pyromorphite-mimetite series"- Master Thesis, AGH-University of Science and Technology, Faculty of Geology, Geophysics and Environmental Protection, Department of Mineralogy, Petrography and Geochemistry, Cracow, Poland. MA Q.Y., TRAINA S.J., LOGAN T.J., RYAN J.A. (1993). "In-situ lead immobilization by apatite". Environ. Sci. Technol., 27: 1803-1810. MAURICE P.A, LEE Y.J., HERSMAN L.E. (1999). "Dissolution of Al-substituted goethites by an aerobic Pseudomonas mendocina var. Bacteria." Gechim. Cosmochim. Acta. 64: 1363-1374. MAGALHÃES M.C.F. (2002). "Arsenic. An environmental problem limited by solubility". Pure Appl. Chem., 74(10): 1843-1850. MAGALHÃES M.C.F., SLIVA, M.C.M.(2003). "Stability of lead(II) arsenates". Monat. fur Chem. 134: 735-743 NRIAGU J.O., (1974). "Lead orthophosphates IV. Formation and stability in the environment." Geochim. Cosmochim. Acta, 37: 367-377. RODRIGUEZ H. & FRAGA R. (1999). "Phosphate solubilizing bacteria and their role in plant growth promotion". Biotechn. Advan. 17: 319-339. WELCH S.A., TAUNTON A.E., BANFIELD J.F. (2002). "Effect of Microorganisms and Microbial Metabolites on Apatite Dissolution". Geomicrobil. J. 19: 343-367.

Combined SCI and TBI: Recovery of forelimb function after unilateral cervical spinal cord injury (SCI) is retarded by contralateral traumatic brain injury (TBI), and ipsilateral TBI balances the effects of SCI on paw placement

PubMed Central

Inoue, Tomoo; Lin, Amity; Ma, Xiaokui; McKenna, Stephen L.; Creasey, Graham H.; Manley, Geoffrey T.; Ferguson, Adam R.; Bresnahan, Jacqueline C.; Beattie, Michael S.

2015-01-01

A significant proportion (estimates range from 16–74%) of patients with spinal cord injury (SCI) have concomitant traumatic brain injury (TBI), and the combination often produces difficulties in planning and implementing rehabilitation strategies and drug therapies. For example, many of the drugs used to treat SCI may interfere with cognitive rehabilitation, and conversely drugs that are used to control seizures in TBI patients may undermine locomotor recovery after SCI. The current paper presents an experimental animal model for combined SCI and TBI to help drive mechanistic studies of dual diagnosis. Rats received a unilateral SCI (75 kdyn) at C5 vertebral level, a unilateral TBI (2.0 mm depth, 4.0 m/s velocity impact on the forelimb sensori-motor cortex), or both SCI + TBI. TBI was placed either contralateral or ipsilateral to the SCI. Behavioral recovery was examined using paw placement in a cylinder, grooming, open field locomotion, and the IBB cereal eating test. Over 6 weeks, in the paw placement test, SCI + contralateral TBI produced a profound deficit that failed to recover, but SCI + ipsilateral TBI increased the relative use of the paw on the SCI side. In the grooming test, SCI + contralateral TBI produced worse recovery than either lesion alone even though contralateral TBI alone produced no observable deficit. In the IBB forelimb test, SCI + contralateral TBI revealed a severe deficit that recovered in 3 weeks. For open field locomotion, SCI alone or in combination with TBI resulted in an initial deficit that recovered in 2 weeks. Thus, TBI and SCI affected forelimb function differently depending upon the test, reflecting different neural substrates underlying, for example, exploratory paw placement and stereotyped grooming. Concurrent SCI and TBI had significantly different effects on outcomes and recovery, depending upon laterality of the two lesions. Recovery of function after cervical SCI was retarded by the addition of a moderate TBI in the contralateral hemisphere in all tests, but forepaw placements were relatively increased by an ipsilateral TBI relative to SCI alone, perhaps due to the dual competing injuries influencing the use of both forelimbs. These findings emphasize the complexity of recovery from combined CNS injuries, and the possible role of plasticity and laterality in rehabilitation, and provide a start towards a useful preclinical model for evaluating effective therapies for combine SCI and TBI. PMID:23770071

Combined SCI and TBI: recovery of forelimb function after unilateral cervical spinal cord injury (SCI) is retarded by contralateral traumatic brain injury (TBI), and ipsilateral TBI balances the effects of SCI on paw placement.

PubMed

Inoue, Tomoo; Lin, Amity; Ma, Xiaokui; McKenna, Stephen L; Creasey, Graham H; Manley, Geoffrey T; Ferguson, Adam R; Bresnahan, Jacqueline C; Beattie, Michael S

2013-10-01

A significant proportion (estimates range from 16 to 74%) of patients with spinal cord injury (SCI) have concomitant traumatic brain injury (TBI), and the combination often produces difficulties in planning and implementing rehabilitation strategies and drug therapies. For example, many of the drugs used to treat SCI may interfere with cognitive rehabilitation, and conversely drugs that are used to control seizures in TBI patients may undermine locomotor recovery after SCI. The current paper presents an experimental animal model for combined SCI and TBI to help drive mechanistic studies of dual diagnosis. Rats received a unilateral SCI (75 kdyn) at C5 vertebral level, a unilateral TBI (2.0 mm depth, 4.0 m/s velocity impact on the forelimb sensori-motor cortex), or both SCI+TBI. TBI was placed either contralateral or ipsilateral to the SCI. Behavioral recovery was examined using paw placement in a cylinder, grooming, open field locomotion, and the IBB cereal eating test. Over 6weeks, in the paw placement test, SCI+contralateral TBI produced a profound deficit that failed to recover, but SCI+ipsilateral TBI increased the relative use of the paw on the SCI side. In the grooming test, SCI+contralateral TBI produced worse recovery than either lesion alone even though contralateral TBI alone produced no observable deficit. In the IBB forelimb test, SCI+contralateral TBI revealed a severe deficit that recovered in 3 weeks. For open field locomotion, SCI alone or in combination with TBI resulted in an initial deficit that recovered in 2 weeks. Thus, TBI and SCI affected forelimb function differently depending upon the test, reflecting different neural substrates underlying, for example, exploratory paw placement and stereotyped grooming. Concurrent SCI and TBI had significantly different effects on outcomes and recovery, depending upon laterality of the two lesions. Recovery of function after cervical SCI was retarded by the addition of a moderate TBI in the contralateral hemisphere in all tests, but forepaw placements were relatively increased by an ipsilateral TBI relative to SCI alone, perhaps due to the dual competing injuries influencing the use of both forelimbs. These findings emphasize the complexity of recovery from combined CNS injuries, and the possible role of plasticity and laterality in rehabilitation, and provide a start towards a useful preclinical model for evaluating effective therapies for combine SCI and TBI. Copyright © 2013 Elsevier Inc. All rights reserved.

Sorption/Desorption Interactions of Plutonium with Montmorillonite

NASA Astrophysics Data System (ADS)

Begg, J.; Zavarin, M.; Zhao, P.; Kersting, A. B.

2012-12-01

Plutonium (Pu) release to the environment through nuclear weapon development and the nuclear fuel cycle is an unfortunate legacy of the nuclear age. In part due to public health concerns over the risk of Pu contamination of drinking water, predicting the behavior of Pu in both surface and sub-surface water is a topic of continued interest. Typically it was assumed that Pu mobility in groundwater would be severely restricted, as laboratory adsorption studies commonly show that naturally occurring minerals can effectively remove plutonium from solution. However, evidence for the transport of Pu over significant distances at field sites highlights a relative lack of understanding of the fundamental processes controlling plutonium behavior in natural systems. At several field locations, enhanced mobility is due to Pu association with colloidal particles that serve to increase the transport of sorbed contaminants (Kersting et al., 1999; Santschi et al., 2002, Novikov et al., 2006). The ability for mineral colloids to transport Pu is in part controlled by its oxidation state and the rate of plutonium adsorption to, and desorption from, the mineral surface. Previously we have investigated the adsorption affinity of Pu for montmorillonite colloids, finding affinities to be similar over a wide range of Pu concentrations. In the present study we examine the stability of adsorbed Pu on the mineral surface. Pu(IV) at an initial concentration of 10-10 M was pre-equilibrated with montmorillonite in a background electrolyte at pH values of 4, 6 and 8. Following equilibration, aliquots of the suspensions were placed in a flow cell and Pu-free background electrolyte at the relevant pH was passed through the system. Flow rates were varied in order to investigate the kinetics of desorption and hence gain a mechanistic understanding of the desorption process. The flow cell experiments demonstrate that desorption of Pu from the montmorillonite surface cannot be modeled as a simple first order process. Furthermore, a pH dependence was observed, with less desorbed at pH 4 compared to pH 8. We suggest the pH dependence is likely controlled by reoxidation of Pu(IV) to Pu(V) and aqueous speciation. We will present models used to describe desorption behavior and discuss the implications for Pu transport. References: Kersting, A.B.; Efurd, D.W.; Finnegan, D.L.; Rokop, D.J.; Smith, D.K.; Thompson J.L. (1999) Migration of plutonium in groundwater at the Nevada Test Site, Nature, 397, 56-59. Novikov A.P.; Kalmykov, S.N.; Utsunomiya, S.; Ewing, R.C.; Horreard, F.; Merkulov, A.; Clark, S.B.; Tkachev, V.V.; Myasoedov, B.F. (2006) Colloid transport of plutonium in the far-field of the Mayak Production Association, Russia, Science, 314, 638-641. Santschi, P.H.; Roberts, K.; Guo, L. (2002) The organic nature of colloidal actinides transported in surface water environments. Environ. Sci. Technol., 36, 3711-3719. This work was funded by U. S. DOE Office of Biological & Environmental Sciences, Subsurface Biogeochemistry Research Program, and performed under the auspices of the U. S. Department of Energy by Lawrence Livermore National Security, LLC under Contract DE-AC52-07NA27344. LLNL-ABS-570161

Neuroprotective effects of lycopene in spinal cord injury in rats via antioxidative and anti-apoptotic pathway.

PubMed

Hu, Wei; Wang, Hongbo; Liu, Zhenfeng; Liu, Yanlu; Wang, Rong; Luo, Xiao; Huang, Yifei

2017-03-06

Oxidative damage induced-mitochondrial dysfunction and apoptosis has been widely studied in spinal cord injury (SCI). Lycopene, a polyunsaturated hydrocarbon, has the highest antioxidant capacity compared to the other carotenoids. However, the role of lycopene in SCI is unknown. In the present study, we evaluated the antioxidant effects of lycopene on mitochondrial dysfunction and apoptosis following T10 contusion SCI in rats. The rats were randomized into 5 groups: the sham group, the SCI group and the SCI pre-treated with lycopene (5, 10, or 20mg/kg) group. The SCI group showed increased malondialdehyde (MDA) content, decreased superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) ability, which indicated that SCI could induce oxidative damage. What's more, the SCI group showed decreased mRNA expression of cytochrome b and mitochondrial transcription factor A (Tfam), and decreased mitochondrial membrane potential (ΔYm), which indicated that SCI could induce mitochondrial dysfunction. Besides, the SCI group showed decreased protein expression of bcl-2 and mitochondrial cytochrome C, increased protein expression of cytosolic cytochrome C, cleaved caspase-9, cleaved caspase-3 and bax, and increased TUNEL-positive cell numbers, which indicated that SCI could induce cell apoptosis. Fortunately, the lycopene treatment significantly ameliorated oxidative damage, mitochondrial dysfunction and cell apoptosis via the reversion of those parameters described above in the dose of lycopene of 10 and 20mg/kg. In addition, lycopene significantly ameliorated the hind limb motor disturbances in the SCI+lyco10 group and the SCI+lyco20 group compared with the SCI group. These results suggested that lycopene administration could improve total antioxidant status and might have neuroprotective effects on SCI. Copyright © 2017 Elsevier B.V. All rights reserved.

DOE Office of Scientific and Technical Information (OSTI.GOV)

NEALSON, KENNETH H.

This project had as its goals the understanding of the ecophysiology of the genus Shewanella using various genomics approaches. As opposed to other programs involving Shewanella, this one branched out into the various areas in which Shewanella cells are active, and included both basic and applied studies. All of the work was, to some extent, related to the ability of the bacteria to accomplish electron exchange between the cell and solid state electron acceptors and/or electron donors, a process we call Extracellular Electron Transport, or EET. The major accomplishments related to several different areas: Basic Science Studies: 1. Genetics andmore » genomics of nitrate reduction, resulting in elucidation of atypical nitrate reduction systems in Shewanella oneidensis (MR-1)[2]. 2. Influence of bacterial strain and growth conditions on iron reduction, showing that rates of reduction, extents of reduction, and the formation of secondary minerals were different for different strains of Shewanella [3,4,9]. 3. Comparative genomics as a tool for comparing metabolic capacities of different Shewanella strains, and for predicting growth and metabolism [6,10,15]. In these studies, collaboration with ORNL, PNNL, and 4. Basic studies of electron transport in strain MR-1, both to poised electrodes, and via conductive nanowires [12,13]. This included the first accurate measurements of electrical energy generation by a single cell during electrode growth [12], and the demonstration of electrical conductivity along the length of bacterial nanowires [13]. 5. Impact of surface charge and electron flow on cell movement, cell attachment, cell growth, and biofilm formation [7.18]. The demonstration that interaction with solid state electron acceptors resulted in increased motility [7] led to the description of a phenomenon called electrokinesis. The importance of this for biofilm formation and for electron flow was hypothesized by Nealson & Finkel [18], and is now under study in several laboratories. Applications: 1. Corrosion: Electron flow is often part of the corrosive process, and several studies were done in concert with this proposal with regard to the ability of EET-capable bacteria to enhance, inhibit, or detect corrosion. These included using EET-capable bacteria to detect corrosion in its earliest stages [5], to use corrosion-causing bacteria for the study of the microbe/mineral interface during corrosion [1], and to study the groups of microbes involved with corrosion of natural systems [19]. 2. Bioenergy and microbial fuel cells: The production of electricity by Shewanella was shown early in this program (several years ago) to be dependent on the genes for extracellular electron transport (EET), and applied work involved the testing of various strains and conditions for the optimization of current production by the shewanellae [11,14,16]. 3. Identification of shewanellae strains: Based on similarities seen in genomic comparisons, a rapid method was employed for distinguishing between shewanellae strains [17]. Interactions with other laboratories: This grant was an extension of a grant involving the so-called ?Shewanella Federation?, and as such, a number of our publications were joint with other members of this group. The groups included: 1. Pacific Northwest Laboratories ? 2. Oak Ridge National Labs 3. Michigan State University 4. University of Oklahoma 5. Naval Research Laboratory, Washington DC 6. Burnham Medical Research Institute, San Diego 7. J. Craig Venter Institute, San Diego Education: Graduate Students: Michael Waters, Ph.D. ? at NIST, Washington D.C. Lewis Hsu, Ph.D. ? at NRL, San Diego Howard Harris, Ph.D. ? Postdoc at University, France Everett Salas, Ph.D. ? Scientist at Chevron McLean, Jeffrey, Ph.D. ? Scientist at J. Craig Venter Institute McCrow, John, Ph.D. ? Scientist at J. Craig Venter Institute Postdocs: Mohamed El-Naggar ? Professor of Physics, USC Jinjun Kan ? Senior Researcher at Undergraduatges: During this year, we had three undergraduate researchers in the lab, each working on an aspect of this work, and each involved with an undergraduate honors research project. Publications produced as a result of this funding. 1. Waters, M.S., M.Y. El-Naggar, L. Hsu, C.A. Sturm, A. Luttge, F.E. Udwadia, D.G. Cvitkovitch, S.D. Goodman, and K.H. Nealson. 2009. Simultaneous interferometric measurement of corrosive or demineralizing bacteria and their mineral interfaces. Appl. Environ. Microbiol. 75:1445-1449. 2. Gao, H., Z.K. Yang, S. Barua, S. B. Reed, M.F. Romine, K.H. Nealson, J.K. Fredrickson, J.M. Tiedje, and J. Zhou. 2009. Reduction of nitrate in Shewanella oneidensis depends on atypical NAP and NRF systems with NapB as a preferred electron transport protein from CymA to NapA. The ISME J. 3:966-976. 3. Salas, E.C., W.M. Berelson, D.E. Hammond, A.R. Kampf and K. H. Nealson. 2009. The impact of bacterial strain on the products of dissimilatory iron reduction. Geochim. Cosmochim. Acta. (in press: doi: 10.1016/j.gca.2009.10.039) 4. Salas, E.C., W.M. Berelson, D.E. Hammond, A.R. Kampf, and K. H. Nealson. 2009. The influence of carbon source on the products of dissimilatory iron reduction. Geomicrobiol. J. 26:451-462 [7,18]. 5. Waters, M.S., E.C. Salas, S.D. Goodman, F.E. Udwadia, and K.H. Nealson. 2009. Early detection of oxidized surfaces using Shewanella oneidensis MR-1 as a tool. Biofouling. 25:163-172. 6. Konstantinidis, K., et al. 2009. Comparative systems biology across an evolutionary gradient within the Shewanella genus. Proc. Nat. Acad. Sci. USA 106: 15909-15914. 7. Harris, H.W., M.Y. El-Naggar, O. Bretschger, M.J. Ward, M. F. Romine, A.Y. Obraztsova, and K.H. Nealson. 2010. Electrokinesis is a microbial behavior that requires extracellular electron transport. Proc. Nat. Acad. Sci. 107:326-331 8. Nealson, K.H. 2010. Sediment reactions defy dogma. Nature 463:1033-1034. 9. Salas, E.C., W.M. Berelson, D.E. Hammond, A.R. Kampf, and K.H. Nealson. 2010. The impact of bacterial strain on the products of dissimilatory iron reduction. Geochim. Cosmochim. Acta. 74:574-583. 10. Karpinets, T.V., A.Y Obraztsova, Y. Wang, D.D. Schmoyer, G.H. Kora, B.H. Park, M.H. Serres, M.F. Ropmine, M.L. Land, T.B. Kothe, J.K. Fredrickson, K.H. Nealson, and E.C. Uberbacher 2010. Conserved synteny at the protein family level reveals genes underlying Shewanella species? cold tolerance and predicts their novel phenotypes. Funct. Integr. Genomics 10: 97 ? 110. (DOI 10.1007/s10143-009-0142-y) 11. Bretschger, O., A.C.M. Cheung, F. Mansfeld, and K.H. Nealson. 2010. Comparative microbial fuel cell evaluations of Shewanella spp. Electroanalysis 22: 883-894. 12. McLean, J.S., G. Wanger, Y.A. Gorby, M. Wainstein, J. McQuaid, Shun?ichi Ishii, O. Bretschger, H. Beyanal, K.H. Nealson. 2010. Quantification of electron transfer rates to a solid phase electron acceptor through the stages of biofilm formation from single cells to multicellular communities. Env. Sci. Technol. 44:2721-2717. 13. El-Naggar, M., G. Wanger, K.M. Leung, T.D. Yuzvinsky, G. Southam, J. Yang, W.M. Lau, K.H. Nealson, and Y.A. Gorby. 2010. Electrical Transport Along Bacterial Nanowires from Shewanella oneidensis MR-1 Proc. Nat. Acad. Sci. USA 107:18127-18131. 14. Biffinger, J.C., L.A. Fitzgerald, R. Ray, B.J. Little, S.E. Lizewski, E.R. Petersen, B.R. Ringeisen, W.C. Sanders, P.E. Sheehan, J.J. Pietron, J.W. Baldwin, L.J. Nadeau, G.R. Johnson, M. Ribbens, S.E. Finkel, K.H. Nealson. 2010. The utility of Shewanella japonica for microbial fuel cells. Bioresource Technol. 102:290-297. 15. Rodionov, D. , C. Yang, X. Li, I. Rodionova, Y. Wang, A.Y. Obraztsova, O. P. Zagnitko, R. Overbeek, M. F. Romine, S. Reed, J.K. Fredrickson, K.H. Nealson, A.L. Osterman. 2010. Genomic encyclopedia of sugar utilization pathways in the Shewanella genus. BMC Genomics 2010, 11:494 16. Kan, J., L. Hsu, A.C.M. Cheung, M. Pirbazari, and K.H. Nealson. 2011. Current production by bacterial communities in microbial fuel cells enriched from wastewater sludge with different electron donors. Env. Sci. Technol. 45: 1139-1146. 17. Kan, J. B. Flood, J.P. McCrow, J.S. Kim, L. Tan, and K.H. Nealson. 2011. A rapid fingerprinting approach to distinguish between closely related strains of Shewanella. J. Microbiol. Methods. 86: 62-68. 18. Nealson, K.H. and S.E. Finkel. 2011. Electron flow and biofilms. MRS Bull. 36:380-384. 19. Kan, J., P. Chellamuthu, A. Obraztsova, J.E. Moore, and K.H. Nealson. 2011. Diverse bacterial groups are associated with corrosive lesions at a Granite Mountain Record Vault (GMRV). J. Appl. Microbiol. 111: 329-337. Patents and Inventions: No patents or inventions were created during this funded work.« less

Self-paced brain-computer interface control of ambulation in a virtual reality environment.

PubMed

Wang, Po T; King, Christine E; Chui, Luis A; Do, An H; Nenadic, Zoran

2012-10-01

Spinal cord injury (SCI) often leaves affected individuals unable to ambulate. Electroencephalogram (EEG) based brain-computer interface (BCI) controlled lower extremity prostheses may restore intuitive and able-body-like ambulation after SCI. To test its feasibility, the authors developed and tested a novel EEG-based, data-driven BCI system for intuitive and self-paced control of the ambulation of an avatar within a virtual reality environment (VRE). Eight able-bodied subjects and one with SCI underwent the following 10-min training session: subjects alternated between idling and walking kinaesthetic motor imageries (KMI) while their EEG were recorded and analysed to generate subject-specific decoding models. Subjects then performed a goal-oriented online task, repeated over five sessions, in which they utilized the KMI to control the linear ambulation of an avatar and make ten sequential stops at designated points within the VRE. The average offline training performance across subjects was 77.2 ± 11.0%, ranging from 64.3% (p = 0.001 76) to 94.5% (p = 6.26 × 10(-23)), with chance performance being 50%. The average online performance was 8.5 ± 1.1 (out of 10) successful stops and 303 ± 53 s completion time (perfect = 211 s). All subjects achieved performances significantly different than those of random walk (p < 0.05) in 44 of the 45 online sessions. By using a data-driven machine learning approach to decode users' KMI, this BCI-VRE system enabled intuitive and purposeful self-paced control of ambulation after only 10 minutes training. The ability to achieve such BCI control with minimal training indicates that the implementation of future BCI-lower extremity prosthesis systems may be feasible.

QERx- A Faster than Real-Time Emulator for Space Processors

NASA Astrophysics Data System (ADS)

Carvalho, B.; Pidgeon, A.; Robinson, P.

2012-08-01

Developing software for space systems is challenging. Especially because, in order to be sure it can cope with the harshness of the environment and the imperative requirements and constrains imposed by the platform were it will run, it needs to be tested exhaustively. Software Validation Facilities (SVF) are known to the industry and developers, and provide the means to run the On-Board Software (OBSW) in a realistic environment, allowing the development team to debug and test the software.But the challenge is to be able to keep up with the performance of the new processors (LEON2 and LEON3), which need to be emulated within the SVF. Such processor emulators are also used in Operational Simulators, used to support mission preparation and train mission operators. These simulators mimic the satellite and its behaviour, as realistically as possible. For test/operational efficiency reasons and because they will need to interact with external systems, both these uses cases require the processor emulators to provide real-time, or faster, performance.It is known to the industry that the performance of previously available emulators is not enough to cope with the performance of the new processors available in the market. SciSys approached this problem with dynamic translation technology trying to keep costs down by avoiding a hardware solution and keeping the integration flexibility of full software emulation.SciSys presented “QERx: A High Performance Emulator for Software Validation and Simulations” [1], in a previous DASIA event. Since then that idea has evolved and QERx has been successfully validated. SciSys is now presenting QERx as a product that can be tailored to fit different emulation needs. This paper will present QERx latest developments and current status.

Effects of Spinal Cord Injury in Heart Rate Variability After Acute and Chronic Exercise: A Systematic Review.

PubMed

Buker, Daniel Bueno; Oyarce, Cristóbal Castillo; Plaza, Raúl Smith

2018-01-01

Background: Spinal cord injury (SCI) above T6 is followed by a loss of sympathetic supraspinal control of the heart, disturbing the autonomic balance and increasing cardiovascular risk. Heart rate variability (HRV) is a widely used tool for assessing the cardiac autonomic nervous system and positive adaptations after regular exercise in able-bodied subjects. However, adaptations in SCI subjects are not well known. Objectives: To compare HRV between able-bodied and SCI subjects and analyze the effects of chronic and acute exercise on HRV in the SCI group. Methods: We searched MEDLINE, Embase, Web of Science, SciELO, and Google Scholar databases to July 2016. We selected English and Spanish observational or experimental studies reporting HRV after training or acute exercise in SCI patients. We also included studies comparing HRV in SCI individuals with able-bodied subjects. Animal studies and nontraumatic SCI studies were excluded. We screened 279 articles by title and abstract; of these, we fully reviewed 29 articles. Eighteen articles fulfilled criteria for inclusion in this study. Results: SCI individuals showed lower HRV values in the low frequency band compared to able-bodied subjects. Regular exercise improved HRV in SCI subjects, however time and intensity data were lacking. HRV decreases after an acute bout of exercise on SCI subjects, but recovery kinetics are unknown. Conclusion: HRV is affected following SCI. Able-bodied subjects and SCI individuals have different values of HRV. Acute bouts of exercise change HRV temporarily, and chronic exercise might improve autonomic balance in SCI.

Overview of the Spinal Cord Injury--Quality of Life (SCI-QOL) measurement system.

PubMed

Tulsky, David S; Kisala, Pamela A; Victorson, David; Tate, Denise G; Heinemann, Allen W; Charlifue, Susan; Kirshblum, Steve C; Fyffe, Denise; Gershon, Richard; Spungen, Ann M; Bombardier, Charles H; Dyson-Hudson, Trevor A; Amtmann, Dagmar; Kalpakjian, Claire Z; Choi, Seung W; Jette, Alan M; Forchheimer, Martin; Cella, David

2015-05-01

The Spinal Cord Injury--Quality of Life (SCI-QOL) measurement system was developed to address the shortage of relevant and psychometrically sound patient reported outcome (PRO) measures available for clinical care and research in spinal cord injury (SCI) rehabilitation. Using a computer adaptive testing (CAT) approach, the SCI-QOL builds on the Patient Reported Outcomes Measurement Information System (PROMIS) and the Quality of Life in Neurological Disorders (Neuro-QOL) initiative. This initial manuscript introduces the background and development of the SCI-QOL measurement system. Greater detail is presented in the additional manuscripts of this special issue. Classical and contemporary test development methodologies were employed. Qualitative input was obtained from individuals with SCI and clinicians through interviews, focus groups, and cognitive debriefing. Item pools were field tested in a multi-site sample (n=877) and calibrated using item response theory methods. Initial reliability and validity testing was performed in a new sample of individuals with traumatic SCI (n=245). Five Model SCI System centers and one Department of Veterans Affairs Medical Center across the United States. Adults with traumatic SCI. n/a n/a The SCI-QOL consists of 19 item banks, including the SCI-Functional Index banks, and 3 fixed-length scales measuring physical, emotional, and social aspects of health-related QOL (HRQOL). The SCI-QOL measurement system consists of psychometrically sound measures for individuals with SCI. The manuscripts in this special issue provide evidence of the reliability and initial validity of this measurement system. The SCI-QOL also links to other measures designed for a general medical population.

Bacterial susceptibility patterns in patients with spinal cord injury and disorder (SCI/D): an opportunity for customized stewardship tools.

PubMed

Suda, K J; Patel, U C; Sabzwari, R; Cao, L; Ramanathan, S; Hill, J N; Evans, C T

2016-11-01

Retrospective observational study of bacterial susceptibilities in Veterans with SCI/D as compared to a general patient population. The purpose of this project was to evaluate the prevalence and susceptibility of bacteria isolated from spinal cord injury and disorder (SCI/D) patients as compared with a general patient population and determine whether a SCI/D-specific antibiogram, a report of bacterial susceptibilities used to guide empiric antibiotic selection, would be a useful stewardship tool. Veterans Affairs Medical Center located in Cook county, IL, USA. Microbiology reports from 1 October 2012 to 30 September 2013 were compiled into a SCI/D-specific antibiogram and compared to a non-SCI/D antibiogram. Persons with positive cultures and SCI/D were younger and had a higher Charlson Index as compared to non-SCI/D patients (P<0.0001 for both). Five thousand one hundred and thirty-one unique isolate cultures were evaluated (SCI/D=23.0%). Frequencies of pathogens isolated in SCI/D and non-SCI/D differed. Methicillin-resistant Staphylococcus aureus occurred more frequently in SCI/D (27.8% vs 55.4%; P<0.0001). Gram-negatives had generally lower susceptibilities in SCI/D and a higher frequency of organisms producing extended-spectrum Beta-lactamases (17.6% vs 5.0%; P<0.0001), carbapenem-resistant Enterobacteriaceae (2.4% vs 0.5%; P<0.0001), carbapenem resistance (7.6% vs 2.4%; P<0.0001) and isolates resistant to ⩾3 antibiotic classes (60.7% vs 28.0%; P=0.0001). Different pathogens with poorer susceptibilities are isolated in SCI/D. Thus an SCI/D-specific antibiogram reflective of resistance patterns in these patients may increase the appropriateness of empiric antibiotic selection. The frequency of multi-drug resistant organisms in cultures obtained from patients with SCI/D is worrisome.

Tracking functional status across the spinal cord injury lifespan: linking pediatric and adult patient-reported outcome scores.

PubMed

Tian, Feng; Ni, Pengsheng; Mulcahey, M J; Hambleton, Ronald K; Tulsky, David; Haley, Stephen M; Jette, Alan M

2014-11-01

To use item response theory (IRT) methods to link scores from 2 recently developed contemporary functional outcome measures, the adult Spinal Cord Injury-Functional Index (SCI-FI) and the Pedi SCI (both the parent version and the child version). Secondary data analysis of the physical functioning items of the adult SCI-FI and the Pedi SCI instruments. We used a nonequivalent group design with items common to both instruments and the Stocking-Lord method for the linking. Linking was conducted so that the adult SCI-FI and Pedi SCI scaled scores could be compared. Community. This study included a total sample of 1558 participants. Pedi SCI items were administered to a sample of children (n=381) with SCI aged 8 to 21 years, and of parents/caregivers (n=322) of children with SCI aged 4 to 21 years. Adult SCI-FI items were administered to a sample of adults (n=855) with SCI aged 18 to 92 years. Not applicable. Five scales common to both instruments were included in the analysis: Wheelchair, Daily Routine/Self-care, Daily Routine/Fine Motor, Ambulation, and General Mobility functioning. Confirmatory factor analysis and exploratory factor analysis results indicated that the 5 scales are unidimensional. A graded response model was used to calibrate the items. Misfitting items were identified and removed from the item banks. Items that function differently between the adult and child samples (ie, exhibit differential item functioning) were identified and removed from the common items used for linking. Domain scores from the Pedi SCI instruments were transformed onto the adult SCI-FI metric. This IRT linking allowed estimation of adult SCI-FI scale scores based on Pedi SCI scale scores and vice versa; therefore, it provides clinicians with a means of tracking long-term functional data for children with an SCI across their entire lifespan. Copyright © 2014 American Congress of Rehabilitation Medicine. Published by Elsevier Inc. All rights reserved.

SciDAC-Data, A Project to Enabling Data Driven Modeling of Exascale Computing

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mubarak, M.; Ding, P.; Aliaga, L.

The SciDAC-Data project is a DOE funded initiative to analyze and exploit two decades of information and analytics that have been collected by the Fermilab Data Center on the organization, movement, and consumption of High Energy Physics data. The project will analyze the analysis patterns and data organization that have been used by the NOvA, MicroBooNE, MINERvA and other experiments, to develop realistic models of HEP analysis workflows and data processing. The SciDAC-Data project aims to provide both realistic input vectors and corresponding output data that can be used to optimize and validate simulations of HEP analysis. These simulations aremore » designed to address questions of data handling, cache optimization and workflow structures that are the prerequisites for modern HEP analysis chains to be mapped and optimized to run on the next generation of leadership class exascale computing facilities. We will address the use of the SciDAC-Data distributions acquired from Fermilab Data Center’s analysis workflows and corresponding to around 71,000 HEP jobs, as the input to detailed queuing simulations that model the expected data consumption and caching behaviors of the work running in HPC environments. In particular we describe in detail how the Sequential Access via Metadata (SAM) data handling system in combination with the dCache/Enstore based data archive facilities have been analyzed to develop the radically different models of the analysis of HEP data. We present how the simulation may be used to analyze the impact of design choices in archive facilities.« less

Assessment of NgR1 Function In Vivo After Spinal Cord Injury

PubMed Central

Tong, Jing; Ren, Yi; Wang, Xiaowei; Dimopoulos, Vassilios G.; Kesler, Henry N.; Liu, Weimin; He, Xiaosheng; Nedergaard, Maiken; Huang, Jason H.

2014-01-01

Background: Neuronal Nogo-66 receptor 1 (NgR1) has attracted attention as a converging point for mediating the effects of myelin-associate inhibitory ligands in the CNS, establishing the growth restrictive environment, and limiting axon regeneration following traumatic injury. Objective: The importance of NgR1 has been undermined by several studies that have shown the lack of substantial axon regeneration following spinal cord injury (SCI) in NgR1 knockout or knockdown animal models. This study aims to investigate the factors that may be contributing to the discrepancy. Methods: We used mice carrying either a homozygous or heterozygous null mutation in the NgR1 gene and subjected them to either a moderate or severe SCI. Results: Locomotor function assessments revealed that the level of functional recovery is affected by the degree of injury suffered. NgR1 ablation enhanced local collateral sprouting in the mutant mice. Reactive astrocytes and chondroitin sulfate proteoglycans (CSPGs) are upregulated surrounding the injury site. MMP-9, which has been shown to degrade CSPGs, was significantly upregulated in the homozygous mutant mice compared to the heterozygous or wild-type mice. However, CSPG levels remained higher in the homozygous compared to the heterozygous mice, suggesting that CSPG-degrading activity of MMP-9 may require the presence of NgR1. Conclusion: Genetic ablation of NgR1 may lead to significant recovery in locomotor function following SCI. The difference in locomotor recovery we observed between the groups that suffered varying degrees of injury suggests that injury severity may be a confounding factor in functional recovery following SCI. PMID:24594926

Quantification of site-city interaction effects on the response of structure under double resonance condition

NASA Astrophysics Data System (ADS)

Kumar, Neeraj; Narayan, Jay Prakash

2018-01-01

This paper presents the site-city interaction (SCI) effects on the response of closely spaced structures under double resonance condition (F_{02{{D}}}^{{S}} = F_{02{{D}}}^{{B}}), where F_{02{{D}}}^{{S}} and F_{02{{D}}}^{{B}} are fundamental frequencies of 2-D structure and 2-D basin, respectively. This paper also presents the development of empirical relations to predict the F_{02{{D}}}^{{B}} of elliptical and trapezoidal basins for both the polarizations of the S wave. Simulated results revealed that F_{02{{D}}}^{{B}} of a 2-D basin very much depends on its geometry, shape ratio and polarization of the incident S wave. The obtained spectral amplification factor (SAF) at F_{02{{D}}}^{{S}} of a standalone structure in a 2-D basin is greater than that in the 1-D case under double resonance condition. A considerable reduction of the fundamental resonance frequency of structures due to the SCI effects is observed for both the polarizations of the S wave. The SAFs at F_{02{{D}}}^{{S}} of closely spaced structures due to SCI effects is larger in the case of SV than SH waves. A splitting of the fundamental-mode frequency bandwidth along with the drastic decrease of SAF due to the SCI effects is obtained. The findings of this paper raise the question concerning the validity of the predicted response of standalone structure based on soil-structure interaction for the design of structures in a 2-D small basin, in an urban environment.

Towards a global historical emission inventory for selected PCB congeners--a mass balance approach 3. An update.

PubMed

Breivik, Knut; Sweetman, Andy; Pacyna, Jozef M; Jones, Kevin C

2007-05-15

Previously published estimates of the global production, consumption and atmospheric emissions of 22 individual PCB congeners [Breivik K, Sweetman A, Pacyna JM, Jones KC. Towards a global historical emission inventory for selected PCB congeners - a mass balance approach. 1. Global production and consumption. Sci Total Environ 2002a; 290: 181-198.; Breivik K, Sweetman A, Pacyna JM, Jones KC. Towards a global historical emission inventory for selected PCB congeners--a mass balance approach. 2. Emissions. Sci Total Environ 2002b; 290: 181-198.] have provided useful information for later studies attempting to interpret contaminant levels in remote areas as well as in the global environment. As a result of the need for more contemporary emission data (following the year 2000), an update of this emission database is presented. This exercise takes into account new information on PCB production in Poland, as well as new data on the chemical composition of various technical mixtures for which less information had been available. The methodology to estimate temporal trends of PCB emissions associated with various types of PCB usage is improved. Projected emissions up to year 2100 are presented to facilitate predictions of future environmental exposure. The national emission data for each of the 114 countries considered is spatially resolved on a 1 degrees x1 degrees grid for each congener and year, using population density as a surrogate.

In-situ single particle composition analysis of free tropospheric ice nuclei and ice residues in mixed-phase clouds during INUIT-JFJ 2013

NASA Astrophysics Data System (ADS)

Schmidt, Susan; Schneider, Johannes; Thomas, Klimach; Stephan, Mertes; Ludwig, Schenk; Udo, Kästner; Frank, Stratmann; Joachim, Curtius; Piotr, Kupiszewski; Ernest, Weingartner; Emanuel, Hammer; Paul, Vochezer; Martin, Schnaiter; Stephan, Borrmann

2014-05-01

In the framework of the DFG (deutsche Forschungsgemeinschaft)-funded research unit INUIT (Ice Nuclei research UnIT) a field campaign at the High Alpine Research Station Jungfraujoch (JFJ, Swiss Alps, Sphinx Laboratory, 3580 m asl; 7°59'2''E, 46°32'53''N) took place in January/February 2013 (INUIT-JFJ 2013). The goal of the measurements was to investigate the chemical composition of ice particle residues (IPR) in ambient air as well as the background aerosol particles. Previous investigations conducted at the JFJ showed that particles consisting of mineral components dominate the ice particle residue number (Kamphus et al., 2008) but also particles consisting of black carbon were found to be enriched in IPR (Mertes et al., 2007; Cozic et al., 2008). Cziczo et al. find out that lead as well is a good ice nucleus and was measured in IPR at previous measurements at the JFJ. During INUIT-JFJ 2013, the IPR were sampled out of mixed-phase clouds by an Ice-CVI (Ice Counterflow Virtual Impactor, Mertes et al., 2007) and an ISI (Ice Selective Inlet, Kupiszewski et al., 2013) and analyzed by the single particle mass spectrometer ALABAMA (Aircraft-based Laser Ablation Aerosol Mass Spectrometer; Brands et al., 2011). Additionally, the ALABAMA was connected to a total aerosol-inlet to investigate the chemical composition of background aerosol particles. During 217 hours of background aerosol measurements we analyzed more than 27000 aerosol particles, which consisted mainly of pure organic components or organics mixed with ammonium, metals or mineral components. During six cloud events with approximately 63 h measurement time we detected 162 IPR sampled by the Ice-CVI. The main part of these IPR were also composed of organic material mixed with other chemical compounds. Additionally, we found particles which consisted of mineral components (approximately 23 %). Sampling mixed-phase cloud through the ISI we measured during four cloud events 34 ice residues in approximately 30 h measurement time. The main part of the chemical compounds of these IPR were also organic material mixed with metals or with mineral compounds. We also found a smaller part of particles which consisted of pure mineral components (about 48 %). Lead was also found in the IPR measured behind Ice-CVI (~14 %) as well as in the background aerosol (~0.04 %). Black carbon particles were only found in the background aerosol. Because of the topography of the JFJ, air masses can reach the station only from the northwestern or southeastern direction (Hammer et al., 2013). Back trajectory calculations show that during our measurements the air masses were dominated mainly by long-distance transport from North America over Great Britain and France. This may explain the lower abundance of mineral dust in the ice residues compared to the previous studies. Brands, M., Kamphus, M., Böttger, T., Schneider, J., Drewnick, F., Roth, A., Curtius, J., Voigt, C., Borbon, A., Beekmann, M., Bourdon, A., Perrin, T. and Borrmann, S. (2011) Aerosol Sci. Technol., 45, 46-64. Cozic, J., Mertes, S., Verheggen, B., Cziczo, D. J., Gallavardin, S. J., Walter, S., Baltensperger, U. and Weingartner, E. (2008) J. Geophys. Res.-Atmos., 113, D15209. Cziczo, D. J., Stetzer. O., Worringen, A., Ebert, M., Weinbruch, S., Kamphus, M., Gallavardin, S. J., Curtius, J., Borrmann, S., Froyd, K. D., Mertes, S., Möhler, O., Lohmann, U. (2009) Nature Geoscience, 2, 333-336 Hammer, E., Bukowiecki, N., Gysel, M., Jurányi, Z., Hoyle, C. R., Vogt, R., Baltensperger, U. and Weingartner, E. (2013) Atmos. Chem. Phys. Discuss., 13, 20419-20462 Kamphus, M., Ettner-Mahl, M., Klimach, T., Drewnick, F, Keller, L., Cziczo, D. J., Mertes, S., Borrmann, S. and Curtius1, J. (2010) Atmos. Chem. Phys., 10, 8077-8095. Kupiszewski, P., Weingartner, E., Färber, R., Gysel, M., Hammer, E., Fuchs, C., Baltensperger, U., Vochezer, P., Schnaiter, M., Linke, C., Toprak, E., Mertes, S., Schneider, J., Schmidt, S. (2013) European Aerosol Conference, Prague. Mertes, S., Verheggen, B., Walter,S., Connolly,P., Ebert, M., Schneider, J., Bower, K. N., Cozic, J., Weinbruch, S., Baltensperger, U. and Weingartner, E. (2007) Aerosol Sci. Technol., 41, 848-864.

Uranium in surface soils: an easy-and-quick assay combining X-ray diffraction and fluorescence qualitative data

NASA Astrophysics Data System (ADS)

Figueiredo, M. O.; Silva, T. P.; Batista, M. J.; Leote, J.; Ferreira, M. L.; Limpo, V.

2009-04-01

Portugal has been a uranium-producer since the beginning of the last century. The uranium-rich area of Alto Alentejo, East-central Portugal, was identified more than fifty years ago [1]. Almost all the uranium-bearing mineralization occurs in schistose rocks of the contact metamorphic aureole produced by intrusion of the Hercynian monzonitic granite of Alto Alentejo into the pre-Ordovitian schist-greywacke complex forming deposits of vein and dissemination type. The Nisa uranium-reservoir, situated at the sharp border of a large and arch shaped granite pluton, was identified in 1957 [2] but its exploitation was considered economically impracticable until recently. However, its existence and the accumulated detritus of these prospect efforts are a concern for local populations [3]. A study of the near-surface soils close to the Nisa reservoir was therefore undertaken to assess the uranium retention by adsorption on clay components under the form of uranyl ions, [UO2]2+ [4-6] and its eventual release into the aquifer groundwater. As an attempt to very quickly appraise the presence of uranium in as-collected near-surface sediment samples a combination of laboratory X-ray techniques was designed: X-ray diffraction (XRD) to identify the mineral phases and roughly estimate its relative proportion plus X-ray fluorescence spectrometry in wavelength dispersive mode (XRF-WDS) to ascertain the presence of uranium and tentatively evaluate its content by comparison with selected chemical components of the soil. A description of the experimental methodology adopted for the implemented easy-and-quick uranium assay is presented. Obtained results compare quite well to the data of certified time-consuming analytical tests of uranium in those soil samples. [1] L. Pilar (1966) Conditions of formation of Nisa uranium deposit (in Portuguese). Comunic. Serv. Geol. Portugal, tomo L, 50-85. [2] C. Gonçalves & J.V. Teixeira Lopes (1971) Uranium deposit of Nisa: geological aspects of its discovery and valorisation (in Portuguese). Internal Rept., JEN, 20 pp. [3] http://www.naturtejo.com [4] J.A. Davis et al. (2006) Processes affecting transport of uranium in a suboxic aquifer. Phys. Chem. of the Earth 31, 548-555. [5] Y. Arai et al. (2007) Spectroscopic evidence for uranium bearing precipitates in Vadose zone sediments at the Hanford 300-Area site. Environ. Sci. Technol. 41, 4633-4639. [6] A. Kremleva, S. Krüger & N. Rösch (2008) Density functional model studies of uranyl adsorption on (001) surfaces of kaolinite. Langmuir 24, 9515-9524.

GHG monitoring over Paris megacity and Orléans forest

NASA Astrophysics Data System (ADS)

Te, Y. V.; Jeseck, P.; Zanon, T.; Boursier, C.; Janssen, C.; Deutscher, N. M.; Warneke, T.; Notholt, J.; Lac, C.; Dieudonné, E.; Lopez, M.; Schmidt, M.; Xueref-remy, I. C.

2012-12-01

In a growing world with more than 7 billion inhabitants and big emerging countries such as China, Brazil and India, emissions of anthropogenic pollutants and greenhouse gases (GHGs) are increasing continuously. Their monitoring and control in megacities have become a major challenge for scientists and public health authorities in environmental research area. The ground-based Fourier transform spectrometer (QualAir FTS[a], model IFS 125HR) of the QualAir platform located in downtown Paris at University Pierre et Marie Curie (UPMC), is a scientific research instrument dedicated to the survey of greenhouse gases (GHGs) and urban air quality. Equipped with a sun-tracker, the remote sensing QualAir FTS relies on solar infrared absorption for monitoring trace gas concentrations and their variability in the Ile-de-France region[b]. Concentrations of atmospheric GHGs, especially CO2, CH4 and N2O, are retrieved by the radiative transfer model PROFFIT[c]. Because Paris is the third largest European megacity, the QualAir FTS can provide new and complementary measurements as compared to existing ground-based FTS network stations (NDACC and TCCON) located in unpolluted environments, such as the TCCON-Orléans station[d] situated in the forest of Orléans (100 km south of Paris). In the effort to integrate QualAir FTS into the TCCON network, simultaneous FTS measurements of GHGs at Paris and Orléans have been performed. We will emphasize on comparisons of CO2 from these two sites. Our comparison will be completed by high-resolved direct CO2 modeling outputs from the Meso-NH model, and ground in situ measurements at different sites (Orléans/Trainou, Paris/Jussieu, Paris/Eiffel Tower). Parts of the data were acquired in the framework of the French CO2-MEGAPARIS project[e, f], whose main goal is to quantify CO2 emissions from the Paris area. The present data intercomparison will help to reduce uncertainties in carbon cycle models and to better characterize regional GHG fluxes, especially with respect to anthropogenic emission sources (urban versus rural) and trends. References: [a] Té et al., J. Atmos. Oceanic Technol., 29, 911-921, 2012 [b] Té et al., Rev. Sci. Instrum., 81, 103102, 2010 [c] Hase et al., JQSRT, 87, 25-52, 2004 [d] https://tccon-wiki.caltech.edu/Sites/Orleans [e] http://co2-megaparis.lsce.ipsl.fr/ [f] Xueref-Remy et al., Abstract n°A13F-0277, AGU Fall Meeting 2010, San Francisco, USA

Cyclo-octafluorobutane (PFC-318) in the global atmosphere

NASA Astrophysics Data System (ADS)

Muhle, J.; Vollmer, M. K.; Fraser, P. J.; Rhee, T. S.; Ivy, D. J.; Arnold, T.; Harth, C. M.; Salameh, P.; O'Doherty, S.; Young, D.; Steele, P.; Krummel, P. B.; Leist, M.; Schmidbauer, N.; Lunder, C.; Kim, J.; Kim, K.; Reimann, S.; Simmonds, P.; Prinn, R. G.; Weiss, R. F.

2010-12-01

PFC-318 (c-C4F8, cyclo-octafluorobutane) is a long-lived (3200 years) perfluorocarbon (PFC) greenhouse gas with a high 100-year Global Warming Potential (GWP100 = 10,300) and a wide range of industrial uses. We extend previous atmospheric measurements of PFC-318 in the Cape Grim Air Archive (Oram, 1999) with our new in situ measurements from remote and urban AGAGE (Advanced Global Atmospheric Gases Experiment) and affiliated stations. Our longest in situ record is from the Jungfraujoch observatory in the Swiss Alps, and our data set is augmented by measurements of flasks from the King Sejong and Troll coastal Antarctic stations and several locations in the Northern Hemisphere. In mid-2009 we find ˜1.25 ppt (parts-per-trillion, dry mol fraction) in the Northern Hemisphere and ˜1.20 ppt in the Southern Hemisphere, with rise rates of ˜0.03 ppt/yr and an interhemispheric ratio of ˜1.04. We obtain PFC-318 emissions for 2008-2010 of ˜1 Gg/yr using a simple box model, and preliminary measurements of older archived air at SIO indicate similar emissions since at the least the late 1990s. In contrast, the EDGAR v4 emissions database estimates much lower PFC-318 emissions of 0.02 Gg/yr for 2005. Using GWP100 we calculate ˜10 million tons of CO2-equivalent PFC-318 emissions/yr for 2008-2010, about double the CO2-equivalent PFC-218 annual emissions, or 0.4 times the CO2-equivalent PFC-116 annual emissions, reported for 2008-2009 by Mühle et al. (2010). Thus PFC-318 is the third most important PFC in terms of CO2-equivalent emissions. We find mostly baseline conditions at remote AGAGE stations and urban sites in the USA, Europe, and Australia, in contrast to frequent above baseline conditions at Gosan station, Jeju Island, South Korea, indicating significant emission sources in East Asia as found by Saito et al. (2010). Oram, D.E., Trends of long-lived anthropogenic halocarbons in the Southern Hemisphere and model calculation of global emissions, Ph.D. thesis, University of East Anglia, Norwich, U.K., 1999. Mühle et al., Perfluorocarbons in the global atmosphere: tetrafluoromethane, hexafluoroethane, and octafluoropropane, Atmos. Chem. Phys., 10(11), 5145-5164, doi:10.5194/acp-10-5145-2010, 2010. Saito et al., Large Emissions of Perfluorocarbons in East Asia Deduced from Continuous Atmospheric Measurements, Environ. Sci. Technol., 44(11), 4089-4095, doi:10.1021/es1001488, 2010.

National Centers for Environmental Prediction

Science.gov Websites

references for past and current documentation: Sort A-Z | Sort by Year Alpert, J.C., S-Y Hong and Y-J Kim -Scale Environment, Part I. J. Atmos. Sci., 31, 674-704. Asselin, R., 1972: Frequency filter for time observations and model computations. J. Clim. and Appl. Meteo., 25, 214-226. Campana, K. A., Y-T Hou, K. E

2015 Marine Corps Security Environment Forecast: Futures 2030-2045

DTIC Science & Technology

2015-01-01

The technologies that make the iPhone “smart” were publically funded—the Internet, wireless networks, the global positioning system, microelectronics...Energy Revolution (63 percent);  Internet of Things (ubiquitous sensors embedded in interconnected computing devices) (50 percent);  “Sci-Fi...Neuroscience & artificial intelligence - Sensors /control systems -Power & energy -Human-robot interaction Robots/autonomous systems will become part of the

Lipid Peroxidation and Its Role in the Expression of NLRP1a and NLRP3 Genes in Testicular Tissue of Male Rats: a Model of Spinal Cord Injury

PubMed

Bazrafkan, Mahshid; Nikmehr, Banafsheh; Shahverdi, Abdolhossein; Hosseini, Seyed Reza; Hassani, Fatemeh; Poorhassan, Mahnaz; Mokhtari, Tahmineh; Abolhassani, Farid; Choobineh, Hamid; Beyer, Cordian; Hassanzadeh, Gholamreza

2017-10-16

The majority of male patients with spinal cord injury (SCI) suffer from infertility. Nucleotide-binding oligomerization domain-like receptors NOD-like receptors (NLRs) are a kind of receptors that corporate in the inflammasome complex. Recent studies have introduced the inflammasome as the responsible agent for secreting cytokines in semen. Reactive oxygen species (ROS) is one of the elements that trigger inflammasome activation. Genital infections in SCI can lead to ROS generation. We investigated the relation between lipid peroxidation and inflammasome complex activity in testicular tissue of SCI rats. Adult male rats (n=20), weighting 200-250 g, were included and divided into four groups: three experimental groups, including SCI1, SCI3, and SCI7, i.e. the rats were subjected to SCI procedure and sacrificed after one, three, and seven days, respectively and a control group. We performed a moderate, midline spinal contusion injury at thoracic level 10. The animals were anesthetized, and testes were collected for measurement of gene expression by real-time PCR. Caudal parts of epididymis were collected for malondialdehyde (MDA) measurement. No NLRP1a mRNA over expression was seen in the testes of control and SCI groups. After seven days from SCI surgery, NLRP3 mRNA expression was significantly increased in SCI7 animals (P≤0.05). There was a significant difference in MDA level in SCI7 versus control group, as well as SCI1 and SCI3 animals (P≤0.05). NLRP3 overexpression occurs due to the increased ROS production in testicular tissue of SCI rats.

Lipid Peroxidation and Its Role in the Expression of NLRP1a and NLRP3 Genes in Testicular Tissue of Male Rats: A Model of Spinal Cord Injury

PubMed Central

Bazrafkan, Mahshid; Nikmehr, Banafsheh; Shahverdi, Abdolhossein; Hosseini, Seyed Reza; Hassani, Fatemeh; Poorhassan, Mahnaz; Mokhtari, Tahmineh; Abolhassani, Farid; Choobineh, Hamid; Beyer, Cordian; Hassanzadeh, Gholamreza

2018-01-01

Background: The majority of male patients with spinal cord injury (SCI) suffer from infertility. Nucleotide-binding oligomerization domain-like receptors NOD-like receptors (NLRs) are a kind of receptors that corporate in the inflammasome complex. Recent studies have introduced the inflammasome as the responsible agent for secreting cytokines in semen. Reactive oxygen species (ROS) is one of the elements that trigger inflammasome activation. Genital infections in SCI can lead to ROS generation. We investigated the relation between lipid peroxidation and inflammasome complex activity in testicular tissue of SCI rats. Methods: Adult male rats (n=20), weighting 200-250 g, were included and divided into four groups: three experimental groups, including SCI1, SCI3, and SCI7, i.e. the rats were subjected to SCI procedure and sacrificed after one, three, and seven days, respectively and a control group. We performed a moderate, midline spinal contusion injury at thoracic level 10. The animals were anesthetized, and testes were collected for measurement of gene expression by real-time PCR. Caudal parts of epididymis were collected for malondialdehyde (MDA) measurement. Results: No NLRP1a mRNA overexpression was seen in the testes of control and SCI groups. After seven days from SCI surgery, NLRP3 mRNA expression was significantly increased in SCI7 animals (p ≤ 0.05). There was a significant difference in MDA level in SCI7 versus control group, as well as SCI1 and SCI3 animals (p ≤ 0.05). Conclusion: NLRP3 overexpression occurs due to the increased ROS production in testis tissue of SCI rats

Overview of the Spinal Cord Injury – Quality of Life (SCI-QOL) measurement system

PubMed Central

Tulsky, David S.; Kisala, Pamela A.; Victorson, David; Tate, Denise G.; Heinemann, Allen W.; Charlifue, Susan; Kirshblum, Steve C.; Fyffe, Denise; Gershon, Richard; Spungen, Ann M.; Bombardier, Charles H.; Dyson-Hudson, Trevor A.; Amtmann, Dagmar; Z. Kalpakjian, Claire; W. Choi, Seung; Jette, Alan M.; Forchheimer, Martin; Cella, David

2015-01-01

Context/Objective The Spinal Cord Injury – Quality of Life (SCI-QOL) measurement system was developed to address the shortage of relevant and psychometrically sound patient reported outcome (PRO) measures available for clinical care and research in spinal cord injury (SCI) rehabilitation. Using a computer adaptive testing (CAT) approach, the SCI-QOL builds on the Patient Reported Outcomes Measurement Information System (PROMIS) and the Quality of Life in Neurological Disorders (Neuro-QOL) initiative. This initial manuscript introduces the background and development of the SCI-QOL measurement system. Greater detail is presented in the additional manuscripts of this special issue. Design Classical and contemporary test development methodologies were employed. Qualitative input was obtained from individuals with SCI and clinicians through interviews, focus groups, and cognitive debriefing. Item pools were field tested in a multi-site sample (n = 877) and calibrated using item response theory methods. Initial reliability and validity testing was performed in a new sample of individuals with traumatic SCI (n = 245). Setting Five Model SCI System centers and one Department of Veterans Affairs Medical Center across the United States. Participants Adults with traumatic SCI. Interventions n/a Outcome Measures n/a Results The SCI-QOL consists of 19 item banks, including the SCI-Functional Index banks, and 3 fixed-length scales measuring physical, emotional, and social aspects of health-related QOL (HRQOL). Conclusion The SCI-QOL measurement system consists of psychometrically sound measures for individuals with SCI. The manuscripts in this special issue provide evidence of the reliability and initial validity of this measurement system. The SCI-QOL also links to other measures designed for a general medical population. PMID:26010962

Investigating "The Coolest School in America": How Technology Is Used in a Learner-Centered School

ERIC Educational Resources Information Center

Aslan, Sinem; Reigeluth, Charles M.

2016-01-01

Reigeluth et al. ("Educ Technol" 48(6):32-39, 2008) proposed major and secondary functions for educational technology systems for the learner-centered paradigm of education. However, the functions proposed should be formatively evaluated and revised using a variety of cases to develop a better understanding of how technology can support…

Bacterial Degradation of Nitrogenous Energetic Compounds (NEC) in Coastal Waters and Sediments

DTIC Science & Technology

2008-09-10

2006) Enzymatic immobilization of 2,4,6-trinitrotoluene (TNT) biodegradation products onto model humic substances. Enzyme Microbial Technol 39:1197...11 2.3 Heterotrophic bacterial production ...collected May 2006: A) Average (AVG) rates of TNT incorporation and bacterial production (μg C L-1 d-1); and, B) TNT incorporation normalized for

Compact, High Power, Multi-Spectral Mid-Infrared Semiconductor Laser Package

DTIC Science & Technology

2001-10-01

depositions to map out effects due to stress in the films. Stress in the film will result in the substrate curvature. This curvature results in the...Lasers at 4.5 µm”, IEEE Photon. Technol. Lett., vol. 9, pp. 1573-1575, (1997). 58 18. A. N. Baranov, N. Bertru, Y. Cuminal , G. Boissier, C. Alibert, and

Three Dimensionally Interconnected Silicon Nanomembranes for Optical Phased Array (OPA) and Optical True Time Delay (TTD) Applications

DTIC Science & Technology

2012-06-01

Nanophotonic Waveguides," J. Lightwave Technol. 25 (1), 151-156 (2007). [7-4] Yongbo Tang, Zhechao Wang, Lech Wosinski, Urban Westergren, and Sailing...Waveguides," Photonics Journal, IEEE 3 (2), 203-208 (2011). [8-25] Zhechao Wang, Ning Zhu, Yongbo Tang, Lech Wosinski, Daoxin Dai, and Sailing He

Evaluation of Magnetostrictive Shunt Damper Performance Using Iron (Fe)-Gallium (Ga) Alloy

DTIC Science & Technology

2013-09-01

Technol. 2003, 11 (4), 482– 494 3. Manning, K. V.; Watanabe, K.; Drake, A. E.; Wright, A. Eddy Current. in AccessScience , ©McGraw-Hill Education...2012, http://www.accessscience.com. 4. Manning, K. V. Lenz’s Law in AccessScience , ©McGraw-Hill Education, 2012, http://www.accessscience.com 5

High Temperature Bonding Techniques for Solar Cell Array

DTIC Science & Technology

1977-11-01

Kedaya, E. , Kawakami, J. K., Kopf, P. W. , Kwiatkowski, G. T., McNeil, D. W. , and Tulis , R. W., "Union Carbide Rept. " UCRI-735 (30 July 1973...6. Peters, E. N., Kedaya, E., Kawakami, J. K. , Kwiatkowski, G. T. , McNeil, D. W., and Tulis , R. W., Rubber Chem. and Technol. 48 (1), 14-18 (1975

Study of the genetic diversity of the aflatoxin biosynthesis cluster in Aspergillus section Flavi using insertion/deletion markers in peanut seeds from Georgia, USA

USDA-ARS?s Scientific Manuscript database

Aflatoxins are among the most powerful carcinogens in nature. The major aflatoxin-producing fungi are Aspergillus flavus and A. parasiticus. Numerous crops, including peanut, are susceptible to aflatoxin contamination by these fungi. There has been an increased use of RNA interference (RNAi) technol...

Circulating sclerostin is elevated in short-term and reduced in long-term SCI

PubMed Central

Battaglino, Ricardo A.; Sudhakar, Supreetha; Lazzari, Antonio; Garshick, Eric; Zafonte, Ross; Morse, Leslie R.

2012-01-01

Spinal cord injury (SCI) causes profound bone loss due to muscle paralysis resulting in the inability to walk. Sclerostin, a Wnt signaling pathway antagonist produced by osteocytes, is a potent inhibitor of bone formation. Short-term studies in rodent models have demonstrated increased sclerostin in response to mechanical unloading that is reversed with reloading. Although sclerostin inhibition has been proposed as a potential therapy for bone loss, it is not known if sclerostin levels vary with duration of SCI in humans. We analyzed circulating sclerostin in 155 men with varying degrees of SCI who were 1 year or more post-injury. We report that sclerostin levels are greatest in subjects with short-term SCI (≤ 5 years post-injury) and decrease significantly over the first 5 years post-injury. There was no association between sclerostin and injury duration in subjects with long-term SCI (> 5 years post-injury). In subjects with long-term SCI, sclerostin levels were positively associated with lower extremity bone density and bone mineral content. These data suggest that sclerostin levels in SCI are initially increased after SCI in response to mechanical unloading. This response is time-limited and as bone loss progresses, circulating sclerostin is lowest in subjects with severe osteoporosis. These findings support a dual role for sclerostin after SCI: a therapeutic target in acute SCI, and a biomarker of osteoporosis severity in chronic SCI. PMID:22575440

75 FR 24747 - SCI, LLC/Zener-Rectifier Operations Division A Wholly Owned Subsidiary of SCI, LLC/ON...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-05-05

... DEPARTMENT OF LABOR Employment and Training Administration [TA-W-70,235] SCI, LLC/Zener-Rectifier... Adjustment Assistance on October 19, 2009, applicable to workers of SCI LLC/Zener-Rectifier, Operations... Technical Resources were employed on-site at the Phoenix Arizona location of SCI LLC/Zener-Rectifier...

Sensitivity of the SCI-FI/AT in Individuals With Traumatic Spinal Cord Injury.

PubMed

Keeney, Tamra; Slavin, Mary; Kisala, Pamela; Ni, Pengsheng; Heinemann, Allen W; Charlifue, Susan; Fyffe, Denise C; Marino, Ralph J; Morse, Leslie R; Worobey, Lynn A; Tate, Denise; Rosenblum, David; Zafonte, Ross; Tulsky, David; Jette, Alan M

2018-03-31

To examine the ability of the Spinal Cord Injury-Functional Index/Assistive Technology (SCI-FI/AT) measure to detect change in persons with spinal cord injury (SCI). Multisite longitudinal (12-mo follow-up) study. Nine SCI Model Systems programs. Adults (N=165) with SCI enrolled in the SCI Model Systems database. Not applicable. SCI-FI/AT computerized adaptive test (CAT) (Basic Mobility, Self-Care, Fine Motor Function, Wheelchair Mobility, and/or Ambulation domains) completed at discharge from rehabilitation and 12 months after SCI. For each domain, effect size estimates and 95% confidence intervals were calculated for subgroups with paraplegia and tetraplegia. The demographic characteristics of the sample were as follows: 46% (n=76) individuals with paraplegia, 76% (n=125) male participants, 57% (n=94) used a manual wheelchair, 38% (n=63) used a power wheelchair, 30% (n=50) were ambulatory. For individuals with paraplegia, the Basic Mobility, Self-Care, and Ambulation domains of the SCI-FI/AT detected a significantly large amount of change; in contrast, the Fine Motor Function and Wheelchair Mobility domains detected only a small amount of change. For those with tetraplegia, the Basic Mobility, Fine Motor Function, and Self-Care domains detected a small amount of change whereas the Ambulation item domain detected a medium amount of change. The Wheelchair Mobility domain for people with tetraplegia was the only SCI-FI/AT domain that did not detect significant change. SCI-FI/AT CAT item banks detected an increase in function from discharge to 12 months after SCI. The effect size estimates for the SCI-FI/AT CAT vary by domain and level of lesion. Findings support the use of the SCI-FI/AT CAT in the population with SCI and highlight the importance of multidimensional functional measures. Copyright © 2018 American Congress of Rehabilitation Medicine. Published by Elsevier Inc. All rights reserved.

Acute and Chronic Deficits in the Urinary Bladder after Spinal Contusion Injury in the Adult Rat

PubMed Central

Herrera, Juan J.; Haywood-Watson, Ricky J.L.

2010-01-01

Abstract Traumatic spinal cord injury (SCI) permanently alters bladder function in humans. Hematuria and cystitis occur in both human SCI as well as in rodent models of SCI. Others have reported early SCI-dependent disruption to bladder uroepithelial integrity that results in increased permeability to urine and urine-borne substances. This can result in cystitis, or inflammation of the bladder, an ongoing pathological condition present throughout the chronic phase of SCI in humans. The goals of our study were twofold: (1) to begin to examine the inflammatory and molecular changes that occur within the bladder uroepithelium using a clinically-relevant spinal contusion model of injury, and (2) to assess whether these alterations continue into the chronic phase of SCI. Rats received either moderate SCI or sham surgery. Urine was collected from SCI and sham subjects over 7 days or at 7 months to assess levels of excreted proteins. Inflammation in the bladder wall was assessed via biochemical and immunohistochemical methods. Bladder tight junction proteins, mediators of uroepithelial integrity, were also measured in both the acute and chronic phases of SCI. Urine protein and hemoglobin levels rapidly increase following SCI. An SCI-dependent elevation in numbers of neutrophils within the bladder wall peaked at 48 h. Bladder tight junction proteins demonstrate a rapid but transient decrease as early as 2 h post-SCI. Surprisingly, elevated levels of urine proteins and significant deficits in bladder tight junction proteins could be detected in chronic SCI, suggesting that early pathological changes to the bladder may continue throughout the chronic phase of injury. PMID:19891526

Driving forces of individual BVOC emissions from a spruce tree in Central Germany; results from a dynamic enclosure study.

NASA Astrophysics Data System (ADS)

Bourtsoukidis, S.; Dittmann, A.; Jacobi, S.; Bonn, B.

2012-04-01

We have conducted seasonal ambient and emission measurements of a series of biogenic VOCs such as monoterpenes (MT), sesquiterpenes (SQT), isoprene, methanol, methyl chavicol and acetaldehyde. Therefore a plant enclosure technique was applied in order to investigate a Central European spruce forest and its emissions responses to meteorological and environmental parameters. A healthy ≈15m tall Norway spruce tree was selected and a vegetation enclosure technique was applied from April to November 2011. VOCs are measured by PTR-MS, while samples have also been analyzed with GC-MS (Gas Chromatography - Mass Spectrometry) techniques for intercomparison and identification of individual VOCs. E/N ratio was adjusted at 117Td[2] and the primary ion signal (H3O+) was continuously above 4×10^7cps, implying a high sensitivity to our measurements. Temperature, relative humidity, ozone, photosynthetic active radiation (PAR) and CO2 concentrations were continuously measured inside the plant cuvette. Meteorological and environmental parameters (radiation, atmospheric pressure, wind velocity, wind direction, temperature, O3, relative humidity, soil moisture, precipitation, global radiation, H2O, NO, NO2) were measured by HLUG (Hessian Agency for Environment and Geology) and DWD (German Weather Service), 50 meters away from the measuring site. In a peculiar season, which was characterized by a warm spring (temperature anomaly >40C), a wet summer (precipitation anomaly 126-150%) and an extremely dry autumn (precipitation anomaly <50%), VOC emissions were analyzed and studied in order to discern different driving forces for the individual compounds. The suggested[3] empirical beta factor for MT found to be in a reasonable range but the temperature dependency was almost double for daytime compared to nighttime measurements, suggesting that light is also influencing MT emissions. On the contrary, SQT emissions showed similar temperature dependency for both day and night measurements. The beta factor showed a different behavior during the seasons for different compounds implying different driving forces and storage inside the tree. Especially for SQT, there are indications that a storage pool that is getting empty while moving towards winter. Interestingly, it has been found that SQT emissions are not only correlated with ambient temperature but also with high ambient ozone levels. In a wide range of meteorological conditions and ozone concentrations, we found different emission behavior when ozone values are exceeding a critical threshold. [1] Goldstein, A. H. and Galbally, I. E.: Known and unexplored organic constituents in the earth's atmosphere, Environ. Sci. Technol., 41, 1514-1521, 2007. [2] Kim, S., Karl, T., Helmig, D., Daly, R., Rassmusen, R. and Guether, A. : Measurement of atmospheric sesquiterpenes by proton transfer reaction-mass spectrometry (PTR-MS), Atmos. Meas. Tech., 2, 99-112, 2009. [3] Guenther, A.B., Zimmerman, P.R., Harley, P.C., Monson, R.K., Fall, R., 1993. Isoprene and monoterpene emission rate variability: model evaluations and sensitivity analyses, Journal of Geophysical Research., 98, 12609-12617, 1993.

Characterization of key aerosol, trace gas and meteorological properties and particle formation and growth processes dependent on air mass origins in coastal Southern Spain

NASA Astrophysics Data System (ADS)

Diesch, J.; Drewnick, F.; Sinha, V.; Williams, J.; Borrmann, S.

2011-12-01

The chemical composition and concentration of aerosols at a certain site can vary depending on season, the air mass source region and distance from sources. Regardless of the environment, new particle formation (NPF) events are one of the major sources for ultrafine particles which are potentially hazardous to human health. Grown particles are optically active and efficient CCN resulting in important implications for visibility and climate (Zhang et al., 2004). The study presented here is intended to provide information about various aspects of continental, urban and marine air masses reflected by wind patterns of the air arriving at the measurement site. Additionally we will be focusing on NPF events associated with different types of air masses affecting their emergence and temporal evolution. Measurements of the ambient aerosol, various trace gases and meteorological parameters were performed within the framework of the DOMINO (Diel Oxidant Mechanisms In relation to Nitrogen Oxides) project. The field campaign took place from mid-November to mid-December 2008 at the atmospheric research station "El Arenosillo" located at the interface between a natural park, industrial cities (Huelva, Seville) and the Atlantic Ocean. Number and mass as well as PAH and black carbon concentrations were measured in PM1 and size distribution instruments covered the size range 6 nm up to 32 μm. The chemical composition of the non-refractory submicron aerosol was measured by means of an Aerosol Mass Spectrometer (AMS). In order to evaluate the characteristics of different air masses linking local and regional sources as well as NPF processes, characteristic air mass types were classified dependent on backwards trajectory pathways and local meteorology. Large nuclei mode concentrations in the number size distribution were found within continental and urban influenced air mass types due to frequently occurring NPF events. Exploring individual production and sink variables, sulfuric acid was found to be the main particle formation contributor. The AMS analysis showed inorganic sulfate species being substantially higher during the growth stages of urban compared to continentally influenced events that are characterized by lower PM1 mass concentrations mainly composed of oxidized organics. The lowest average PM1 mass and number concentrations (2 μg m-3, 1000 cm-3) were found in marine air mass types characterized by the highest sulfate PM1-fraction (54%, 0.91 μg m-3) and volume size distributions probably dominated by sodium chloride particles from sea spray. Two to five times higher submicron aerosol mass concentrations were observed in continental (2.5 μg m-3) and urban (4.2 μg m-3) air mass types mainly consisting of organic species that were further evaluated using Positive Matrix Factorization (PMF). Zhang, Q. et al. (2004), Environ. Sci. Technol., 38, 4797-4809.

The barriers, benefits and facilitators of leisure time physical activity among people with spinal cord injury: a meta-synthesis of qualitative findings.

PubMed

Williams, Toni Louise; Smith, Brett; Papathomas, Anthony

2014-01-01

Physical activity (PA) can have a positive impact upon health and well-being for people with spinal cord injury (SCI). Despite these benefits, people with SCI are within the most physically inactive segment of society that comprises disabled people. This original meta-synthesis of qualitative research was undertaken to explore the barriers, benefits and facilitators of leisure time physical activity (LTPA) among people with SCI. Articles published since 2000 were identified through a rigorous search of electronic databases, supported with a hand search of relevant journals and papers. In total, 64 papers were read in full, and based on inclusion criteria, 18 were relevant for review. The key themes constructed from the data were summarised, compared and synthesised. Eight interrelated concepts were identified as barriers, benefits and/or facilitators of LTPA: (i) well-being (WB); (ii) environment; (iii) physical body; (iv) body-self relationship; (v) physically active identity; (vi) knowledge; (vii) restitution narrative; (viii) perceived absences. Based on the synthesised evidence, healthcare professionals need to appreciate the relationships between the barriers, benefits and facilitators of LTPA in order to successfully promote a physically active lifestyle. Equally, a more critical attitude to PA promotion is called for in terms of possible adverse consequences.

Targeting Translational Successes through CANSORT-SCI: Using Pet Dogs To Identify Effective Treatments for Spinal Cord Injury.

PubMed

Moore, Sarah A; Granger, Nicolas; Olby, Natasha J; Spitzbarth, Ingo; Jeffery, Nick D; Tipold, Andrea; Nout-Lomas, Yvette S; da Costa, Ronaldo C; Stein, Veronika M; Noble-Haeusslein, Linda J; Blight, Andrew R; Grossman, Robert G; Basso, D Michele; Levine, Jonathan M

2017-06-15

Translation of therapeutic interventions for spinal cord injury (SCI) from laboratory to clinic has been historically challenging, highlighting the need for robust models of injury that more closely mirror the human condition. The high prevalence of acute, naturally occurring SCI in pet dogs provides a unique opportunity to evaluate expeditiously promising interventions in a population of animals that receive diagnoses and treatment clinically in a manner similar to persons with SCI, while adhering to National Institutes of Health guidelines for scientific rigor and transparent reporting. In addition, pet dogs with chronic paralysis are often maintained long-term by their owners, offering a similarly unique population for study of chronic SCI. Despite this, only a small number of studies have used the clinical dog model of SCI. The Canine Spinal Cord Injury Consortium (CANSORT-SCI) was recently established by a group of veterinarians and basic science researchers to promote the value of the canine clinical model of SCI. The CANSORT-SCI group held an inaugural meeting November 20 and 21, 2015 to evaluate opportunities and challenges to the use of pet dogs in SCI research. Key challenges identified included lack of familiarity with the model among nonveterinary scientists and questions about how and where in the translational process the canine clinical model would be most valuable. In light of these, we review the natural history, outcome, and available assessment tools associated with canine clinical SCI with emphasis on their relevance to human SCI and the translational process.

High Prevalence of Stress and Low Prevalence of Alzheimer Disease CSF Biomarkers in a Clinical Sample with Subjective Cognitive Impairment.

PubMed

Eckerström, Marie; Berg, Anne Ingeborg; Nordlund, Arto; Rolstad, Sindre; Sacuiu, Simona; Wallin, Anders

2016-01-01

Subjective cognitive impairment (SCI) is a trigger for seeking health care in a possible preclinical phase of Alzheimer's disease (AD), although the characteristics of SCI need clarification. We investigated the prevalence of psychosocial stress, depressive symptoms and CSF AD biomarkers in SCI and MCI (mild cognitive impairment). Memory clinic patients (SCI: n = 90; age: 59.8 ± 7.6 years; MCI: n = 160; age: 63.7 ± 7.0 years) included in the Gothenburg MCI study were examined at baseline. Variables were analyzed using logistic regression with SCI as dependent variable. Stress was more prevalent in SCI (51.1%) than MCI (23.1%); p < 0.0005. SCI patients had more previous depressive symptoms (p = 0.006), but showed no difference compared to MCI patients considering current depressive symptoms. A positive CSF AD profile was present in 14.4% of SCI patients and 35.0% of MCI patients (p = 0.001). Stress (p = 0.002), previous stress/depressive symptoms (p = 0.006) and a negative CSF AD profile (p = 0.036) predicted allocation to the SCI group. Psychosocial stress is more prevalent in SCI than previously acknowledged. The high prevalence and long-term occurrence of stress/depressive symptoms in SCI in combination with a low prevalence of altered CSF AD biomarkers strengthens the notion that AD is not the most likely etiology of SCI. © 2016 S. Karger AG, Basel.

Use, knowledge, and perception of the scientific contribution of Sci-Hub in medical students: Study in six countries in Latin America.

PubMed

Mejia, Christian R; Valladares-Garrido, Mario J; Miñan-Tapia, Armando; Serrano, Felipe T; Tobler-Gómez, Liz E; Pereda-Castro, William; Mendoza-Flores, Cynthia R; Mundaca-Manay, Maria Y; Valladares-Garrido, Danai

2017-01-01

Sci-Hub is a useful web portal for people working in science as it provides access to millions of free scientific articles. Satisfaction and usage should be explored in the Latino student population. The objective of this study was to evaluate the use, knowledge, and perception of the scientific contribution of Sci-Hub in medical students from Latin America. A multicenter, observational, analytical study was conducted in 6632 medical students from 6 countries in Latin America. We surveyed from a previously validated instrument, delving into knowledge, monthly average usage, satisfaction level, and perception of the scientific contributions provided by Sci-Hub. Frequencies and percentages are described, and generalized linear models were used to establish statistical associations. Only 19.2% of study participants knew of Sci-Hub and its function, while the median use was twice a month. 29.9% of Sci-Hub-aware participants claimed they always find the desired scientific information in their Sci-Hub search; 62.5% of participants affirmed that Sci-Hub contributes to scientific investigation; only 2.2% reported that Sci-Hub does not contribute to science. The majority of Latino students are not aware of Sci-Hub.

Recommendations for the National Institute for Neurologic Disorders and Stroke spinal cord injury common data elements for children and youth with SCI.

PubMed

Mulcahey, M J; Vogel, L C; Sheikh, M; Arango-Lasprilla, J C; Augutis, M; Garner, E; Hagen, E M; Jakeman, L B; Kelly, E; Martin, R; Odenkirchen, J; Scheel-Sailer, A; Schottler, J; Taylor, H; Thielen, C C; Zebracki, K

2017-04-01

In 2014, the adult spinal cord injury (SCI) common data element (CDE) recommendations were made available. This project was a review of the adult SCI CDE for relevance to children and youth with SCI. The objective of this study was to review the National Institute of Neurologic Disorders and Stroke (NINDS) adult SCI CDEs for relevance to children and youth with SCI. International. The pediatric working group consisted of international members with varied fields of expertise related to pediatric SCI. The group convened biweekly meetings for 6 months in 2015. All of the adult SCI CDEs were reviewed, evaluated and modified/created for four age groups: 0-5 years, 6-12 years, 13-15 years and 16-18 years. Whenever possible, results of published research studies were used to guide recommendations. In the absence of empirical support, grey literature and international content expert consensus were garnered. Existing pediatric NINDS CDEs and new CDEs were developed in areas where adult recommendations were not appropriate. After internal working group review of domain recommendations, these pediatric CDEs were vetted during a public review from November through December 2015. Version 1.0 of the pediatric SCI CDEs was posted in February 2016. The pediatric SCI CDEs are incorporated directly into the NINDS SCI CDE sets and can be found at https://commondataelements.ninds.nih.gov.

Development of an Acetate- or Sugar-fed Microbial Power Generator for Military Bases

DTIC Science & Technology

2012-07-01

Lovley, L. M. Tender, Energy Environ. Sci. 2011, 4, 896–913. [10] a) E. F. Dalton, N. A. Surridge, J. C. Jernigan, K. O. Wilbourn , J. S. Facci, R. W...Microbiol. 2010, 76, 3999–4007; b) X. L. Qian, T. Mester, L. Morgado, T. Arakawa, M. L. Sharma, K. Inoue, C. Joseph , C. A. Salgueiro, M. J. Maroney, D

Wireless Communications in Reverberant Environments

DTIC Science & Technology

2015-01-01

Secure Wireless Agent Testbed (SWAT), the Protocol Engineering Advanced Networking (PROTEAN) Research Group, the Data Fusion Laboratory (DFL), and the...constraints of their application. 81 Bibliography [1] V. Gungor and G. Hancke, “Industrial wireless sensor networks : Challenges, design principles, and...Bhattacharya, “Path loss estimation for a wireless sensor network for application in ship,” Int. J. of Comput. Sci. and Mobile Computing, vol. 2, no. 6, pp

Spinal cord injury below-level neuropathic pain relief with dorsal root entry zone microcoagulation performed caudal to level of complete spinal cord transection.

PubMed

Falci, Scott; Indeck, Charlotte; Barnkow, Dave

2018-06-01

OBJECTIVE Surgically created lesions of the spinal cord dorsal root entry zone (DREZ) to relieve central pain after spinal cord injury (SCI) have historically been performed at and cephalad to, but not below, the level of SCI. This study was initiated to investigate the validity of 3 proposed concepts regarding the DREZ in SCI central pain: 1) The spinal cord DREZ caudal to the level of SCI can be a primary generator of SCI below-level central pain. 2) Neuronal transmission from a DREZ that generates SCI below-level central pain to brain pain centers can be primarily through sympathetic nervous system (SNS) pathways. 3) Perceived SCI below-level central pain follows a unique somatotopic map of DREZ pain-generators. METHODS Three unique patients with both intractable SCI below-level central pain and complete spinal cord transection at the level of SCI were identified. All 3 patients had previously undergone surgical intervention to their spinal cords-only cephalad to the level of spinal cord transection-with either DREZ microcoagulation or cyst shunting, in failed attempts to relieve their SCI below-level central pain. Subsequent to these surgeries, DREZ lesioning of the spinal cord solely caudal to the level of complete spinal cord transection was performed using electrical intramedullary guidance. The follow-up period ranged from 1 1/2 to 11 years. RESULTS All 3 patients in this study had complete or near-complete relief of all below-level neuropathic pain. The analyzed electrical data confirmed and enhanced a previously proposed somatotopic map of SCI below-level DREZ pain generators. CONCLUSIONS The results of this study support the following hypotheses. 1) The spinal cord DREZ caudal to the level of SCI can be a primary generator of SCI below-level central pain. 2) Neuronal transmission from a DREZ that generates SCI below-level central pain to brain pain centers can be primarily through SNS pathways. 3) Perceived SCI below-level central pain follows a unique somatotopic map of DREZ pain generators.

The Operational plans for Ptolemy during the Rosetta mission

NASA Astrophysics Data System (ADS)

Morse, Andrew; Andrews, Dan; Barber, Simeon; Sheridan, Simon; Morgan, Geraint; Wright, Ian

2014-05-01

Ptolemy is a Gas Chromatography - Isotope Ratio - Mass Spectrometer (GC-IR-MS) instrument within the Philae Lander, part of ESA's Rosetta mission [1]. The primary aim of Ptolemy is to analyse the chemical and isotopic composition of solid comet samples. Samples are collected by the Sampler, Drill and Distribution (SD2) system [2] and placed into ovens for analysis by three instruments on the Lander: COSAC [3], ÇIVA[4] and/or Ptolemy. In the case of Ptolemy, the ovens can be heated with or without oxygen and the evolved gases separated by chemical and GC techniques for isotopic analysis. In addition Ptolemy can measure gaseous (i.e. coma) samples by either directly measuring the ambient environment within the mass spectrometer or by passively trapping onto an adsorbent phase in order to pre-concentrate coma species before desorbing into the mass spectrometer. At the time of this presentation the Rosetta spacecraft should have come out of hibernation and Ptolemy's Post Hibernation Commissioning phase will have been completed. During the Comet Approach phase of the mission Ptolemy will attempt to measure the coma composition both in sniffing and pre-concentration modes. Previous work has demonstrated that spacecraft outgassing is a significant component of the gaseous environment and highlighted the advantage of obtaining complementary measurements with different instruments [5]. In principle Ptolemy could study the spatial evolution of gases through the coma during the lander's descent to the comet surface, but in practice it is likely that mission resources will need to be fully directed towards ensuring a safe landing. Once on the surface of the comet the lander begins its First Science Sequence which continues until the primary batteries are exhausted after some 42 hours. SD2 will collect a sample from a depth of ~5cm and deliver it to a Ptolemy high temperature oven which will then be analysed in five temperature steps to determine the carbon isotopic composition of CO, CO2 and organics; the nitrogen isotopic composition of N2 and organics; and the oxygen isotopic composition of water. The Long Term Science phase of the lander relies on Solar power and the secondary batteries. There will be intermittent operations of Ptolemy to measure the temporal evolution of the coma gas as the comet activity increases. As sufficient power becomes available Ptolemy can continue with more detailed analyses of further comet samples extracted by SD2. [1] Glassmeier, K-H. et al. (2007) Space Sci. Rev., 128, 1 [2] Finzi, E. et al (2007) Space Sci. Rev., 128, 281 [3] Goesmann, F. et al (2007) Space Sci. Rev., 128, 257 [4] Bibring, J-P. et al. (2007) Space Sci. Rev., 128, 397 [5] Morse A.D. (2012) et al. Planetary and Space Sci., 66, 165

Not just quantity: gluteus maximus muscle characteristics in able-bodied and SCI individuals--implications for tissue viability.

PubMed

Wu, Gary A; Bogie, Kath M

2013-08-01

Some individuals with spinal cord injury (SCI) remain pressure ulcer (PU) free whilst others experience a recurring cycle of tissue breakdown. Detailed analysis of gluteal muscle characteristics may provide insights to local tissue viability variability. The study hypothesis was that SCI individuals have altered muscle composition compared to able-bodied (AB). Ten AB and ten SCI received a supine pelvic CT scan, with contrast. Cross-sectional area (CSA) and overall muscle volume were derived using image analysis. Gluteal muscle tissue type was classified at the S2/S3 sacral vertebrae midpoint, the superior greater trochanters margin (GT) and the inferior ischial tuberosities margin (IT) using the linear transformation Hounsfield Unit scale. SCI gluteal CSA was less than for AB throughout the muscle, with the greatest relative atrophy at the IT (48%). Average AB gluteal volume was nearly double SCI. Eight SCI had over 20% infiltrative adipose tissue, three with over 50%. SCI gluteal CSA and intramuscular fat infiltration were significantly negatively correlated (p < 0.05). SCI IT axial slices showed less lean muscle and higher intramuscular fat infiltration than more proximally (p < 0.05). SCI gluteal muscle characteristics were indicative of impaired tissue viability. SCI disuse muscle atrophy was anticipated; the analytic approach further indicated that intramuscular atrophy was not uniform. SCI muscle composition showed increased proportions of both low density muscle and adipose tissue. CT scan with contrast is effective for gluteal muscle characterization. This assessment technique may contribute to determination of personalized risk for PU development and other secondary complications. Published by Elsevier Ltd.

Targeting Translational Successes through CANSORT-SCI: Using Pet Dogs To Identify Effective Treatments for Spinal Cord Injury

PubMed Central

Granger, Nicolas; Olby, Natasha J.; Spitzbarth, Ingo; Jeffery, Nick D.; Tipold, Andrea; Nout-Lomas, Yvette S.; da Costa, Ronaldo C.; Stein, Veronika M.; Noble-Haeusslein, Linda J.; Blight, Andrew R.; Grossman, Robert G.; Basso, D. Michele; Levine, Jonathan M.

2017-01-01

Abstract Translation of therapeutic interventions for spinal cord injury (SCI) from laboratory to clinic has been historically challenging, highlighting the need for robust models of injury that more closely mirror the human condition. The high prevalence of acute, naturally occurring SCI in pet dogs provides a unique opportunity to evaluate expeditiously promising interventions in a population of animals that receive diagnoses and treatment clinically in a manner similar to persons with SCI, while adhering to National Institutes of Health guidelines for scientific rigor and transparent reporting. In addition, pet dogs with chronic paralysis are often maintained long-term by their owners, offering a similarly unique population for study of chronic SCI. Despite this, only a small number of studies have used the clinical dog model of SCI. The Canine Spinal Cord Injury Consortium (CANSORT-SCI) was recently established by a group of veterinarians and basic science researchers to promote the value of the canine clinical model of SCI. The CANSORT-SCI group held an inaugural meeting November 20 and 21, 2015 to evaluate opportunities and challenges to the use of pet dogs in SCI research. Key challenges identified included lack of familiarity with the model among nonveterinary scientists and questions about how and where in the translational process the canine clinical model would be most valuable. In light of these, we review the natural history, outcome, and available assessment tools associated with canine clinical SCI with emphasis on their relevance to human SCI and the translational process. PMID:28230415

Microbiology of Fresh Comminuted Turkey Meat

DTIC Science & Technology

1976-04-12

823 Reprinted from J. Milk Food Technol. Vol. 39. No. 12. Pages 823-829 (December. 1976) Cooyright 1976, International Association of Milk , Food, and...most probable number (MPN) method (13). niacin, and riboflavin (29). Canadian officials have proposed microbial standards The literature contains...onto Mueller-Hinton agar plates containing 5% various retail markets in the San Francisco Bay Area. They were defibrinated sheep blood. Representative

JPRS Report China

DTIC Science & Technology

1988-05-23

materials and teach them the technol- ogy. Once armed with the technology, they went into business on their own, borrowing capital from overseas Chinese or...opened this year. 12802 AGRICULTURE Projects Supported by National Natural Science Foundation 40060239 Beijing ZHIWU XUEBAO [ACTA BOTANICA SINICAJ...On Research in Educational Psychology; * 1. Research in the psychology of esthetics; * 2. Study and application of psychology of teaching ; 3

Lethal and Legal The Ethics of Drone Strikes

DTIC Science & Technology

2015-12-01

analysis, evaluation, and refinement of professional expertise in war, strategy, operations, national security, resource management , and responsible...in business studies and holds an M.Phil. in defence and security studies from the Defence College of Management and Technol- ogy, Defence Academy...in unsafe buildings, search and rescue missions in treacherous conditions, police searches for missing or wanted persons, traffic management , public

Software Development for Decision Analysis

DTIC Science & Technology

1975-03-01

to p Pollution Cost/lb Sulfur Emitted ( Flue Gas Desulfurization ) 178 3.11 Sensitivity of Total Societal Cost/KWH to...34 and "FGD ( flue gas desulfurization ) technology" have all been represented. The branching structure shown in Figure 3.7 (and for that matter each... Gas Desulfurization ) technol- ogy" are decision variables representing possible means of sulfur oxide emission control avallabie for the electric

Learning about the Earth through Societally-relevant Interdisciplinary Research Projects: the Honours Integrated Science Program at McMaster

NASA Astrophysics Data System (ADS)

Eyles, C.; Symons, S. L.; Harvey, C. T.

2016-12-01

Students in the Honours Integrated Science (iSci) program at McMaster University (Hamilton, Ontario, Canada) learn about the Earth through interdisciplinary research projects that focus on important societal issues. The iSci program is a new and innovative undergraduate program that emphasizes the links between scientific disciplines and focuses on learning through research and the development of scientific communication skills. The program accepts up to 60 students each year and is taught by a team of 18 instructors comprising senior and junior faculty, post-doctoral fellows, a lab coordinator, instructional assistant, a librarian and library staff, and an administrator. The program is designed around a pedagogical model that emphasizes hands-on learning through interdisciplinary research (Research-based Integrated Education: RIE) and is mostly project-based and experiential. In their freshman year students learn fundamental Earth science concepts (in conjunction with chemistry, physics, mathematics and biology) through research projects focused on environmental contamination, interplanetary exploration, the effect of drugs on the human body and environment, sustainable energy, and cancer. In subsequent years they conduct research on topics such as the History of the Earth, Thermodynamics, Plant-Animal Interactions, Wine Science, Forensics, and Climate Change. The iSci program attracts students with a broad interest in science and has been particularly effective in directing high quality students into the Earth sciences as they are introduced to the discipline in their first year of study through research projects that are interesting and stimulating. The structure of the iSci program encourages consideration of geoscientific applications in a broad range of societally relevant research projects; these projects are reviewed and modified each year to ensure their currency and ability to meet program learning objectives.

Novel Sensor Technology To Assess Independence and Limb-Use Laterality in Cervical Spinal Cord Injury.

PubMed

Brogioli, Michael; Popp, Werner L; Albisser, Urs; Brust, Anne K; Frotzler, Angela; Gassert, Roger; Curt, Armin; Starkey, Michelle L

2016-11-01

After spinal cord injury (SCI), levels of independence are commonly assessed with standardized clinical assessments. However, such tests do not provide information about the actual extent of upper limb activities or the impact on independence of bi- versus unilateral usage throughout daily life following cervical SCI. The objective of this study was to correlate activity intensity and laterality of upper extremity activity measured by body-fixed inertial measurement units (IMUs) with clinical assessment scores of independence. Limb-use intensity and laterality of activities performed by the upper extremities was measured in 12 subjects with cervical SCI using four IMUs (positioned on both wrists, on the chest, and on one wheel of the wheelchair). Algorithms capable of reliably detecting self-propulsion and arm activity in a clinical environment were applied to rate functional outcome levels, and were related to clinical independence measures during inpatient rehabilitation. Measures of intensity of upper extremity activity during self-propulsion positively correlated (p < 0.05, r = 0.643) with independence measures related to mobility. Clinical measures of laterality were positively correlated (p < 0.01, r = 0.900) with laterality as measured by IMUs during "daily life," and increased laterality was negatively correlated (p < 0.01, r = -0.739) with independence. IMU sensor technology is sensitive in assessing and quantifying upper limb-use intensity and laterality in human cervical SCI. Continuous and objective movement data of distinct daily activities (i.e., mobility and day-to-day activities) can be related to levels of independence. Therefore, IMU sensor technology is suitable not only for monitoring activity levels during rehabilitation (including during clinical trials) but could also be used to assess levels of participation after discharge.

Combining neurotrophin-transduced schwann cells and rolipram to promote functional recovery from subacute spinal cord injury.

PubMed

Flora, Govinder; Joseph, Gravil; Patel, Samik; Singh, Amanpreet; Bleicher, Drew; Barakat, David J; Louro, Jack; Fenton, Stephanie; Garg, Maneesh; Bunge, Mary Bartlett; Pearse, Damien D

2013-01-01

Following spinal cord injury (SCI), both an inhibitory environment and lack of intrinsic growth capacity impede axonal regeneration. In a previous study, prevention of cyclic adenosine monophosphate (AMP) hydrolysis by the phosphodiesterase-4 inhibitor rolipram, in combination with Schwann cell (SC) grafts, promoted significant supraspinal and proprioceptive fiber growth and/or sparing and improved locomotion. In another study, transplanted SCs transduced to generate a bifunctional neurotrophin (D15A) led to significant increases in graft SCs and axons, including supraspinal and myelinated axons. Here we studied the growth and myelination of local and supraspinal axons and functional outcome following the combination of rolipram administration and neurotrophin-transduced SC implantation after SCI. Rolipram was administered subcutaneously for 4 weeks immediately after contusion at vertebral T8 (25.0-mm weight drop, MASCIS impactor). GFP or GFP-D15A-transduced SCs were injected into the injury epicenter 1 week after SCI. GFP-D15A SC grafts and GFP SC grafts with rolipram contained significantly more serotonergic fibers compared to GFP SCs. SC myelinated axons were increased significantly in GFP SC with rolipram-treated animals compared to animals receiving SCI alone. Rolipram administered with either GFP or GFP-D15A SCs significantly increased numbers of brain stem-derived axons below the lesion/implant area and improved hindlimb function. Compared to the single treatments, the combination led to the largest SC grafts, the highest numbers of serotonergic fibers in the grafts, and increased numbers of axons from the reticular formation below the lesion/implant area and provided the greatest improvement in hindlimb function. These findings demonstrate the therapeutic potential for a combination therapy involving the maintenance of cyclic AMP levels and neurotrophin-transduced SCs to repair the subacutely injured spinal cord.

A Spanish version of the Skin Cancer Index: a questionnaire for measuring quality of life in patients with cervicofacial nonmelanoma skin cancer.

PubMed

de Troya-Martín, M; Rivas-Ruiz, F; Blázquez-Sánchez, N; Fernández-Canedo, I; Aguilar-Bernier, M; Repiso-Jiménez, J B; Toribio-Montero, J C; Jones-Caballero, M; Rhee, J

2015-01-01

The Skin Cancer Index (SCI) is the first specific patient-reported outcome measure for patients with cervicofacial nonmelanoma skin cancer. To date, only the original English version has been published. To develop a Spanish version of the SCI that is semantically and linguistically equivalent to the original, and to evaluate its measurement properties in this different cultural environment. A cross-sectional study was conducted of the cultural adaptation and empirical validation of the questionnaire, analysing the psychometric properties of the new index at different stages. Of 440 patients recruited to the study, 431 (95%) completed the Spanish version of the SCI questionnaire, in a mean time of 6·3 min (SD 2·9). Factor analysis of the scale revealed commonality and loading values of < 0·5 for three of the 15 items. The remaining 12 items converged into two components: appearance/social aspects (seven items) and emotional aspects (five items). Both domains presented a high level of internal consistency, with Cronbach's alpha values above 0·8. The convergent-discriminant validity analysis produced correlations higher than 0·3 for the mental component of the Short Form Health Survey-12v2 Health Questionnaire (correlation coefficient 0·39) and the Dermatology Quality of Life Index (correlation coefficient -0·30). In the test-retest, nine of the 12 items produced a weighted kappa value exceeding 0·4, and for the remaining three items, the absolute agreement percentage exceeded 60%. The Spanish version of the SCI quality of life scale has been satisfactorily adapted and validated for use in Spanish-speaking countries and populations. © 2014 British Association of Dermatologists.

Spinal-Cord-Injured Individual's Experiences of Having a Partner: A Phenomenological-Hermeneutic Study.

PubMed

Angel, Sanne

2015-06-01

Having a partner is a strong factor in adaptation to the new life situation with a spinal cord injury (SCI). Still, more knowledge in detail about the partner's influences according to the experiences of individuals with SCI could contribute to the understanding of the situation after an injury. The aim of this phenomenological-hermeneutic article is to achieve a deeper understanding of nine individuals' experiences the first 2 years after SCI. In rehabilitation after SCI, the partner supported the SCI individual's life spirit by not giving up and by still seeing possibilities in the future. The partner reinforced the SCI individual's commitment to life by sharing experiences; providing love, trust, and hope; and giving priority to the best things in life for the SCI individual. This implied cohabitation providing concrete help and an intimacy that helped to cope with problems and anxieties and allowed SCI individuals the ability to self-realize. This promoted feelings of profound gratitude but also dependency. Thus, the SCI individual benefitted from the partner's support mentally and physically, which enabled a life that would not otherwise be possible.

Global meaning in people with spinal cord injury: Content and changes

PubMed Central

Littooij, Elsbeth; Widdershoven, Guy A.M.; Stolwijk-Swüste, Janneke M.; Doodeman, Suzan; Leget, Carlo J.W.; Dekker, Joost

2016-01-01

Background After spinal cord injury (SCI), people are confronted with abrupt discontinuity in almost all areas of life, leading to questions on how to live a meaningful life again. Global meaning refers to basic ideas and goals that guide people in giving meaning to their lives, in specific situations. Little is known about global meaning relating to SCI and whether global meaning changes after SCI. Purpose The purpose of this study was twofold: (i) to explore the content of global meaning of people with SCI, and (ii) to explore whether or not global meaning changes after SCI. Methods In-depth semi-structured interviews were conducted with 16 people with SCI. Interviews were analyzed according to the method of grounded theory. Results (i) Five aspects of global meaning were found: core values, relationships, worldview, identity and inner posture. (ii) Overall, little change in the content of global meaning was found after SCI; specific aspects of global meaning were foregrounded after SCI. Conclusion Five aspects of global meaning were found in people with SCI. Global meaning seems hardly subject to change. PMID:25615571

Evaluation and Management of SCI-Associated Pain.

PubMed

Saulino, Michael; Averna, Justin F

2016-09-01

Traumatic spinal cord injury (SCI) is a devastating neurological condition. Treatment of SCI-related pain is challenging for the treating physician, as normal neural pathways are disrupted. Patients with SCI consistently rate pain as one of the most difficult problems associated with their injury. SCI-related pain can be refractory and complete relief is often not possible. The multidimensional nature of SCI-related pain affects the neural system including autonomic nervous system deregulation and can alter metabolic and biochemical processes throughout the body. Co-morbid psychological illnesses such as depression and adjustment disorder are seen in a significant percentage of patients. Despite a better understanding of the underlying pain mechanisms and advances in procedural, pharmacologic, and non-pharmacologic therapies, treatment of pain after SCI remains elusive. This manuscript reviews the current evidence-based evaluation and management of the SCI patient with the overarching goal of providing appropriate and effective management of their pain. In particular, additional well-designed studies are needed to help elucidate effective treatments for SCI-related neuropathic pain in an effort to help provide these patients with better management of their pain and improve their quality of life.

Resting-state synchrony between the retrosplenial cortex and anterior medial cortical structures relates to memory complaints in subjective cognitive impairment.

PubMed

Yasuno, Fumihiko; Kazui, Hiroaki; Yamamoto, Akihide; Morita, Naomi; Kajimoto, Katsufumi; Ihara, Masafumi; Taguchi, Akihiko; Matsuoka, Kiwamu; Kosaka, Jun; Tanaka, Toshihisa; Kudo, Takashi; Takeda, Masatoshi; Nagatsuka, Kazuyuki; Iida, Hidehiro; Kishimoto, Toshifumi

2015-06-01

Subjective cognitive impairment (SCI) is a clinical state characterized by subjective cognitive deficits without cognitive impairment. To test the hypothesis that this state might involve dysfunction of self-referential processing mediated by cortical midline structures, we investigated abnormalities of functional connectivity in these structures in individuals with SCI using resting-state functional magnetic resonance imaging. We performed functional connectivity analysis for 23 individuals with SCI and 30 individuals without SCI. To reveal the pathophysiological basis of the functional connectivity change, we performed magnetic resonance-diffusion tensor imaging. Positron emission tomography-amyloid imaging was conducted in 13 SCI and 15 nonSCI subjects. Individuals with SCI showed reduced functional connectivity in cortical midline structures. Reduction in white matter connections was related to reduced functional connectivity, but we found no amyloid deposition in individuals with SCI. The results do not necessarily contradict the possibility that SCI indicates initial cognitive decrements, but imply that reduced functional connectivity in cortical midline structures contributes to overestimation of the experience of forgetfulness. Copyright © 2015 Elsevier Inc. All rights reserved.

32 CFR 154.19 - Reinvestigation.

Code of Federal Regulations, 2011 CFR

2011-07-01

... to Sensitive Compartmented Information (SCI). Each individual having current access to SCI shall be... certain SCI duties may require very special compartmentation and other special security measures. In such... for continued SCI access. (h) Foreign nationals employed by DoD organizations overseas. Foreign...

Measuring stigma after spinal cord injury: Development and psychometric characteristics of the SCI-QOL Stigma item bank and short form.

PubMed

Kisala, Pamela A; Tulsky, David S; Pace, Natalie; Victorson, David; Choi, Seung W; Heinemann, Allen W

2015-05-01

To develop a calibrated item bank and computer adaptive test (CAT) to assess the effects of stigma on health-related quality of life in individuals with spinal cord injury (SCI). Grounded-theory based qualitative item development methods, large-scale item calibration field testing, confirmatory factor analysis, and item response theory (IRT)-based psychometric analyses. Five SCI Model System centers and one Department of Veterans Affairs medical center in the United States. Adults with traumatic SCI. SCI-QOL Stigma Item Bank A sample of 611 individuals with traumatic SCI completed 30 items assessing SCI-related stigma. After 7 items were iteratively removed, factor analyses confirmed a unidimensional pool of items. Graded Response Model IRT analyses were used to estimate slopes and thresholds for the final 23 items. The SCI-QOL Stigma item bank is unique not only in the assessment of SCI-related stigma but also in the inclusion of individuals with SCI in all phases of its development. Use of confirmatory factor analytic and IRT methods provide flexibility and precision of measurement. The item bank may be administered as a CAT or as a 10-item fixed-length short form and can be used for research and clinical applications.

Development and psychometric characteristics of the SCI-QOL Pressure Ulcers scale and short form.

PubMed

Kisala, Pamela A; Tulsky, David S; Choi, Seung W; Kirshblum, Steven C

2015-05-01

To develop a self-reported measure of the subjective impact of pressure ulcers on health-related quality of life (HRQOL) in individuals with spinal cord injury (SCI) as part of the SCI quality of life (SCI-QOL) measurement system. Grounded-theory based qualitative item development methods, large-scale item calibration testing, confirmatory factor analysis (CFA), and item response theory-based psychometric analysis. Five SCI Model System centers and one Department of Veterans Affairs medical center in the United States. Adults with traumatic SCI. SCI-QOL Pressure Ulcers scale. 189 individuals with traumatic SCI who experienced a pressure ulcer within the past 7 days completed 30 items related to pressure ulcers. CFA confirmed a unidimensional pool of items. IRT analyses were conducted. A constrained Graded Response Model with a constant slope parameter was used to estimate item thresholds for the 12 retained items. The 12-item SCI-QOL Pressure Ulcers scale is unique in that it is specifically targeted to individuals with spinal cord injury and at every stage of development has included input from individuals with SCI. Furthermore, use of CFA and IRT methods provide flexibility and precision of measurement. The scale may be administered in its entirety or as a 7-item "short form" and is available for both research and clinical practice.

Measuring stigma after spinal cord injury: Development and psychometric characteristics of the SCI-QOL Stigma item bank and short form

PubMed Central

Kisala, Pamela A.; Tulsky, David S.; Pace, Natalie; Victorson, David; Choi, Seung W.; Heinemann, Allen W.

2015-01-01

Objective To develop a calibrated item bank and computer adaptive test (CAT) to assess the effects of stigma on health-related quality of life in individuals with spinal cord injury (SCI). Design Grounded-theory based qualitative item development methods, large-scale item calibration field testing, confirmatory factor analysis, and item response theory (IRT)-based psychometric analyses. Setting Five SCI Model System centers and one Department of Veterans Affairs medical center in the United States. Participants Adults with traumatic SCI. Main Outcome Measures SCI-QOL Stigma Item Bank Results A sample of 611 individuals with traumatic SCI completed 30 items assessing SCI-related stigma. After 7 items were iteratively removed, factor analyses confirmed a unidimensional pool of items. Graded Response Model IRT analyses were used to estimate slopes and thresholds for the final 23 items. Conclusions The SCI-QOL Stigma item bank is unique not only in the assessment of SCI-related stigma but also in the inclusion of individuals with SCI in all phases of its development. Use of confirmatory factor analytic and IRT methods provide flexibility and precision of measurement. The item bank may be administered as a CAT or as a 10-item fixed-length short form and can be used for research and clinical applications. PMID:26010973

Use, knowledge, and perception of the scientific contribution of Sci-Hub in medical students: Study in six countries in Latin America

PubMed Central

Mejia, Christian R.; Valladares-Garrido, Mario J.; Miñan-Tapia, Armando; Serrano, Felipe T.; Tobler-Gómez, Liz E.; Pereda-Castro, William; Mendoza-Flores, Cynthia R.; Mundaca-Manay, Maria Y.; Valladares-Garrido, Danai

2017-01-01

Introduction Sci-Hub is a useful web portal for people working in science as it provides access to millions of free scientific articles. Satisfaction and usage should be explored in the Latino student population. The objective of this study was to evaluate the use, knowledge, and perception of the scientific contribution of Sci-Hub in medical students from Latin America. Methodology A multicenter, observational, analytical study was conducted in 6632 medical students from 6 countries in Latin America. We surveyed from a previously validated instrument, delving into knowledge, monthly average usage, satisfaction level, and perception of the scientific contributions provided by Sci-Hub. Frequencies and percentages are described, and generalized linear models were used to establish statistical associations. Results Only 19.2% of study participants knew of Sci-Hub and its function, while the median use was twice a month. 29.9% of Sci-Hub-aware participants claimed they always find the desired scientific information in their Sci-Hub search; 62.5% of participants affirmed that Sci-Hub contributes to scientific investigation; only 2.2% reported that Sci-Hub does not contribute to science. Conclusion The majority of Latino students are not aware of Sci-Hub. PMID:28982181

Sleep disordered breathing in chronic spinal cord injury.

PubMed

Sankari, Abdulghani; Bascom, Amy; Oomman, Sowmini; Badr, M Safwan

2014-01-15

Spinal cord injury (SCI) is associated with 2-5 times greater prevalence of sleep disordered breathing (SDB) than the general population. The contribution of SCI on sleep and breathing at different levels of injury using two scoring methods has not been assessed. The objectives of this study were to characterize the sleep disturbances in the SCI population and the associated physiological abnormalities using quantitative polysomnography and to determine the contribution of SCI level on the SDB mechanism. We studied 26 consecutive patients with SCI (8 females; age 42.5 ± 15.5 years; BMI 25.9 ± 4.9 kg/m2; 15 cervical and 11 thoracic levels) by spirometry, a battery of questionnaires and by attended polysomnography with flow and pharyngeal pressure measurements. Inclusion criteria for SCI: chronic SCI (> 6 months post injury), level T6 and above and not on mechanical ventilation. Ventilation, end-tidal CO2 (PETCO2), variability in minute ventilation (VI-CV) and upper airway resistance (RUA) were monitored during wakefulness and NREM sleep in all subjects. Each subject completed brief history and exam, Epworth Sleepiness Scale (ESS), Pittsburgh Sleep Quality Index (PSQI), Berlin questionnaire (BQ) and fatigue severity scale (FSS). Sleep studies were scored twice, first using standard 2007 American Academy of Sleep Medicine (AASM) criteria and second using new 2012 recommended AASM criteria. Mean PSQI was increased to 10.3 ± 3.7 in SCI patients and 92% had poor sleep quality. Mean ESS was increased 10.4 ± 4.4 in SCI patients and excessive daytime sleepiness (ESS ≥ 10) was present in 59% of the patients. Daytime fatigue (FSS > 20) was reported in 96% of SCI, while only 46% had high-risk score of SDB on BQ. Forced vital capacity (FVC) in SCI was reduced to 70.5% predicted in supine compared to 78.5% predicted in upright positions (p < 0.05). Likewise forced expiratory volume in first second (FEV1) was 64.9% predicted in supine compared to 74.7% predicted in upright positions (p < 0.05). Mean AHI in SCI patients was 29.3 ± 25.0 vs. 20.0 ± 22.8 events/h using the new and conventional AASM scoring criteria, respectively (p < 0.001). SCI patients had SDB (AHI > 5 events/h) in 77% of the cases using the new AASM scoring criteria compared to 65% using standard conventional criteria (p < 0.05). In cervical SCI, VI decreased from 7.2 ± 1.6 to 5.5 ± 1.3 L/min, whereas PETCO2 and VI-CV, increased during sleep compared to thoracic SCI. The majority of SCI survivors have symptomatic SDB and poor sleep that may be missed if not carefully assessed. Decreased VI and increased PETCO2 during sleep in patients with cervical SCI relative to thoracic SCI suggests that sleep related hypoventilation may contribute to the pathogenesis SDB in patients with chronic cervical SCI.

Potential of personal health record portals in the care of individuals with spinal cord injuries and disorders: Provider perspectives.

PubMed

Hill, Jennifer N; Smith, Bridget M; Weaver, Frances M; Nazi, Kim M; Thomas, Florian P; Goldstein, Barry; Hogan, Timothy P

2018-05-01

Although personal health record (PHR) portals are designed for patients, healthcare providers are a key influence in how patients use their features and realize benefits from them. A few studies have examined provider attitudes toward PHR portals, but none have focused on those who care for individuals with spinal cord injuries and disorders (SCI/D). We characterize SCI/D provider perspectives of PHR portals, including perceived advantages and disadvantages of PHR portal use in SCI/D care. Cross-sectional; semi-structured interviews. Spinal Cord Injury (SCI) Centers in the Veterans Health Administration. Twenty-six SCI/D healthcare providers. None. Perceived advantages and disadvantages of PHR portals. The complex situations of individuals with SCI/D shaped provider perspectives of PHR portals and their potential role in practice. Perceived advantages of PHR portal use in SCI/D care included the ability to coordinate information and care, monitor and respond to outpatient requests, support patient self-management activities, and provide reliable health information to patients. Perceived disadvantages of PHR portal use in SCI/D care included concerns about the quality of patient-generated health data, other potential liabilities for providers and workload burden, and the ability of individuals with SCI/D to understand clinical information accessed through a portal. Our study highlights advantages and disadvantages that should be considered when promoting engagement of SCI/D healthcare providers in use of PHR portals, and portal features that may have the most utility in SCI/D care.

Circulating sclerostin is elevated in short-term and reduced in long-term SCI.

PubMed

Battaglino, Ricardo A; Sudhakar, Supreetha; Lazzari, Antonio A; Garshick, Eric; Zafonte, Ross; Morse, Leslie R

2012-09-01

Spinal cord injury (SCI) causes profound bone loss due to muscle paralysis resulting in the inability to walk. Sclerostin, a Wnt signaling pathway antagonist produced by osteocytes, is a potent inhibitor of bone formation. Short-term studies in rodent models have demonstrated increased sclerostin in response to mechanical unloading that is reversed with reloading. Although sclerostin inhibition has been proposed as a potential therapy for bone loss, it is not known if sclerostin levels vary with duration of SCI in humans. We analyzed circulating sclerostin in 155 men with varying degrees of SCI who were 1 year or more post-injury. We report that sclerostin levels are greatest in subjects with short-term SCI (≤5 years post-injury) and decrease significantly over the first 5 years post-injury. There was no association between sclerostin and injury duration in subjects with long-term SCI (>5 years post-injury). In subjects with long-term SCI, sclerostin levels were positively associated with lower extremity bone density and bone mineral content. These data suggest that sclerostin levels are initially increased after SCI in response to mechanical unloading. This response is time-limited and as bone loss progresses, circulating sclerostin is lowest in subjects with severe osteoporosis. These findings support a dual role for sclerostin after SCI: a therapeutic target in acute SCI, and a biomarker of osteoporosis severity in chronic SCI. Copyright © 2012 Elsevier Inc. All rights reserved.

Curcumin Increase the Expression of Neural Stem/Progenitor Cells and Improves Functional Recovery after Spinal Cord Injury

PubMed Central

Bang, Woo-Seok; Kim, Kyoung-Tae; Seo, Ye Jin; Cho, Dae-Chul; Sung, Joo-Kyung; Kim, Chi Heon

2018-01-01

Objective To investigates the effect of curcumin on proliferation of spinal cord neural stem/progenitor cells (SC-NSPCs) and functional outcome in a rat spinal cord injury (SCI) model. Methods Sixty adult male Sprague-Dawley rats were randomly and blindly allocated into three groups (sham control group; curcumin treated group after SCI; vehicle treated group after SCI). Functional recovery was evaluated by the Basso, Beattie, and Bresnahan (BBB) scale during 6 weeks after SCI. The expression of SC-NSPC proliferation and astrogliosis were analyzed by nestin/Bromodeoxyuridine (BrdU) and Glial fibrillary acidic protein (GFAP) staining. The injured spinal cord was then examined histologically, including quantification of cavitation. Results The BBB score of the SCI-curcumin group was better than that of SCI-vehicle group up to 14 days (p<0.05). The co-immunoreactivity of nestin/BrdU in the SCI-curcumin group was much higher than that of the SCI-vehicle group 1 week after surgery (p<0.05). The GFAP immunoreactivity of the SCI-curcumin group was remarkably lower than that of the SCI-vehicle group 4 weeks after surgery (p<0.05). The lesion cavity was significantly reduced in the curcumin group as compared to the control group (p<0.05). Conclusion These results indicate that curcumin could increase the expression of SC-NSPCs, and reduce the activity of reactive astrogliosis and lesion cavity. Consequently curcumin could improve the functional recovery after SCI via SC-NSPC properties. PMID:29354231

Spinal Cord Injury Impairs Cardiovascular Capacity in Elite Wheelchair Rugby Athletes.

PubMed

Gee, Cameron M; Currie, Katharine D; Phillips, Aaron A; Squair, Jordan W; Krassioukov, Andrei V

2017-12-19

To examine differences in heart rate (HR) responses during international wheelchair rugby competition between athletes with and without a cervical spinal cord injury (SCI) and across standardized sport classifications. Observational study. The 2015 Parapan American Games wheelchair rugby competition. Forty-three male athletes (31 ± 8 years) with a cervical SCI (n = 32) or tetraequivalent impairment (non-SCI, n = 11). Average and peak HR (HRavg and HRpeak, respectively). To characterize HR responses in accordance with an athletes' International Wheelchair Rugby Federation (IWRF) classification, we separated athletes into 3 groups: group I (IWRF classification 0.5-1.5, n = 15); group II (IWRF classification 2.0, n = 15); and group III (IWRF classification 2.5-3.5, n = 13). Athletes with SCI had lower HRavg (111 ± 14 bpm vs 155 ± 13 bpm) and HRpeak (133 ± 12 bpm vs 178 ± 13 bpm) compared with non-SCI (both P < 0.001). Average HR was higher in group III than in I (136 ± 25 bpm vs 115 ± 20 bpm, P = 0.045); however, SCI athletes showed no difference in HRavg or HRpeak between groups. Within group III, SCI athletes had lower HRavg (115 ± 6 bpm vs 160 ± 8 bpm) and HRpeak (135 ± 11 bpm vs 183 ± 11 bpm) than non-SCI athletes (both P < 0.001). This study is the first to demonstrate attenuated HR responses during competition in SCI compared with non-SCI athletes, likely due to injury to spinal autonomic pathways. Among athletes with SCI, IWRF classification was not related to differences in HR. Specific assessment of autonomic function after SCI may be able to predict HR during competition and consideration of autonomic impairments may improve the classification process.

Understanding Quality of Life in Adults with Spinal Cord Injury Via SCI-Related Needs and Secondary Complications.

PubMed

Sweet, Shane N; Noreau, Luc; Leblond, Jean; Dumont, Frédéric S

2014-01-01

Understanding the factors that can predict greater quality of life (QoL) is important for adults with spinal cord injury (SCI), given that they report lower levels of QoL than the general population. To build a conceptual model linking SCI-related needs, secondary complications, and QoL in adults with SCI. Prior to testing the conceptual model, we aimed to develop and evaluate the factor structure for both SCI-related needs and secondary complications. Individuals with a traumatic SCI (N = 1,137) responded to an online survey measuring 13 SCI-related needs, 13 secondary complications, and the Life Satisfaction Questionnaire to assess QoL. The SCI-related needs and secondary complications were conceptualized into factors, tested with a confirmatory factor analysis, and subsequently evaluated in a structural equation model to predict QoL. The confirmatory factor analysis supported a 2-factor model for SCI related needs, χ(2)(61, N = 1,137) = 250.40, P <.001, comparative fit index (CFI) = .93, root mean square error of approximation (RMSEA) = .05, standardized root mean square residual (SRMR) = .04, and for 11 of the 13 secondary complications, χ(2)(44, N = 1,137) = 305.67, P < .001, CFI = .91, RMSEA = .060, SRMR = .033. The final 2 secondary complications were kept as observed constructs. In the structural model, both vital and personal development unmet SCI-related needs (β = -.22 and -.20, P < .05, respectively) and the neuro-physiological systems factor (β = -.45, P < .05) were negatively related with QoL. Identifying unmet SCI-related needs of individuals with SCI and preventing or managing secondary complications are essential to their QoL.

Methodology for the development and calibration of the SCI-QOL item banks

PubMed Central

Tulsky, David S.; Kisala, Pamela A.; Victorson, David; Choi, Seung W.; Gershon, Richard; Heinemann, Allen W.; Cella, David

2015-01-01

Objective To develop a comprehensive, psychometrically sound, and conceptually grounded patient reported outcomes (PRO) measurement system for individuals with spinal cord injury (SCI). Methods Individual interviews (n = 44) and focus groups (n = 65 individuals with SCI and n = 42 SCI clinicians) were used to select key domains for inclusion and to develop PRO items. Verbatim items from other cutting-edge measurement systems (i.e. PROMIS, Neuro-QOL) were included to facilitate linkage and cross-population comparison. Items were field tested in a large sample of individuals with traumatic SCI (n = 877). Dimensionality was assessed with confirmatory factor analysis. Local item dependence and differential item functioning were assessed, and items were calibrated using the item response theory (IRT) graded response model. Finally, computer adaptive tests (CATs) and short forms were administered in a new sample (n = 245) to assess test-retest reliability and stability. Participants and Procedures A calibration sample of 877 individuals with traumatic SCI across five SCI Model Systems sites and one Department of Veterans Affairs medical center completed SCI-QOL items in interview format. Results We developed 14 unidimensional calibrated item banks and 3 calibrated scales across physical, emotional, and social health domains. When combined with the five Spinal Cord Injury – Functional Index physical function banks, the final SCI-QOL system consists of 22 IRT-calibrated item banks/scales. Item banks may be administered as CATs or short forms. Scales may be administered in a fixed-length format only. Conclusions The SCI-QOL measurement system provides SCI researchers and clinicians with a comprehensive, relevant and psychometrically robust system for measurement of physical-medical, physical-functional, emotional, and social outcomes. All SCI-QOL instruments are freely available on Assessment CenterSM. PMID:26010963

Methodology for the development and calibration of the SCI-QOL item banks.

PubMed

Tulsky, David S; Kisala, Pamela A; Victorson, David; Choi, Seung W; Gershon, Richard; Heinemann, Allen W; Cella, David

2015-05-01

To develop a comprehensive, psychometrically sound, and conceptually grounded patient reported outcomes (PRO) measurement system for individuals with spinal cord injury (SCI). Individual interviews (n=44) and focus groups (n=65 individuals with SCI and n=42 SCI clinicians) were used to select key domains for inclusion and to develop PRO items. Verbatim items from other cutting-edge measurement systems (i.e. PROMIS, Neuro-QOL) were included to facilitate linkage and cross-population comparison. Items were field tested in a large sample of individuals with traumatic SCI (n=877). Dimensionality was assessed with confirmatory factor analysis. Local item dependence and differential item functioning were assessed, and items were calibrated using the item response theory (IRT) graded response model. Finally, computer adaptive tests (CATs) and short forms were administered in a new sample (n=245) to assess test-retest reliability and stability. A calibration sample of 877 individuals with traumatic SCI across five SCI Model Systems sites and one Department of Veterans Affairs medical center completed SCI-QOL items in interview format. We developed 14 unidimensional calibrated item banks and 3 calibrated scales across physical, emotional, and social health domains. When combined with the five Spinal Cord Injury--Functional Index physical function banks, the final SCI-QOL system consists of 22 IRT-calibrated item banks/scales. Item banks may be administered as CATs or short forms. Scales may be administered in a fixed-length format only. The SCI-QOL measurement system provides SCI researchers and clinicians with a comprehensive, relevant and psychometrically robust system for measurement of physical-medical, physical-functional, emotional, and social outcomes. All SCI-QOL instruments are freely available on Assessment CenterSM.

The role of capsaicin-sensitive C-fiber afferent pathways in the control of micturition in spinal-intact and spinal cord-injured mice.

PubMed

Kadekawa, Katsumi; Majima, Tsuyoshi; Shimizu, Takahiro; Wada, Naoki; de Groat, William C; Kanai, Anthony J; Goto, Momokazu; Yoshiyama, Mitsuharu; Sugaya, Kimio; Yoshimura, Naoki

2017-09-01

We examined bladder and urethral sphincter activity in mice with or without spinal cord injury (SCI) after C-fiber afferent desensitization induced by capsaicin pretreatment and changes in electrophysiological properties of mouse bladder afferent neurons 4 wk after SCI. Female C57BL/6N mice were divided into four groups: 1 ) spinal intact (SI)-control, 2 ) SI-capsaicin pretreatment (Cap), 3 ) SCI-control, and 4 ) SCI-Cap groups. Continuous cystometry and external urethral sphincter (EUS)-electromyogram (EMG) were conducted under an awake condition. In the Cap groups, capsaicin (25, 50, or 100 mg/kg) was injected subcutaneously 4 days before the experiments. In the SI-Cap group, 100 mg/kg capsaicin pretreatment significantly increased bladder capacity and decreased the silent period duration of EUS/EMG compared with the SI-control group. In the SCI-Cap group, 50 and 100 mg/kg capsaicin pretreatment decreased the number of nonvoiding contractions (NVCs) and the duration of reduced EUS activity during voiding, respectively, compared with the SCI-control group. In SCI mice, hexamethonium, a ganglionic blocker, almost completely blocked NVCs, suggesting that they are of neurogenic origin. Patch-clamp recordings in capsaicin-sensitive bladder afferent neurons from SCI mice showed hyperexcitability, which was evidenced by decreased spike thresholds and increased firing rate compared with SI mice. These results indicate that capsaicin-sensitive C-fiber afferent pathways, which become hyperexcitable after SCI, can modulate bladder and urethral sphincter activity in awake SI and SCI mice. Detrusor overactivity as shown by NVCs in SCI mice is significantly but partially dependent on capsaicin-sensitive C-fiber afferents, whereas the EUS relaxation during voiding is enhanced by capsaicin-sensitive C-fiber bladder afferents in SI and SCI mice. Copyright © 2017 the American Physiological Society.

Investigation of Microbiota Alterations and Intestinal Inflammation Post-Spinal Cord Injury in Rat Model.

PubMed

O'Connor, Gregory; Jeffrey, Elisabeth; Madorma, Derik; Marcillo, Alexander; Abreu, Maria T; Deo, Sapna K; Dietrich, W Dalton; Daunert, Sylvia

2018-06-07

Although there has been a significant amount of research focused on the pathophysiology of spinal cord injury (SCI), there is limited information on the consequences of SCI on remote organs. SCI can produce significant effects on a variety of organ systems, including the gastrointestinal tract. Patients with SCI often suffer from severe, debilitating bowel dysfunction in addition to their physical disabilities, which is of major concern for these individuals because of the adverse impact on their quality of life. Herein, we report on our investigation into the effects of SCI and subsequent antibiotic treatment on the intestinal tissue and microbiota. For that, we used a thoracic SCI rat model and investigated changes to the microbiota, proinflammatory cytokine levels, and bacterial communication molecule levels post-injury and gentamicin treatment for 7 days. We discovered significant changes, the most interesting being the differences in the gut microbiota beta diversity of 8-week SCI animals compared to control animals at the family, genus, and species level. Specifically, 35 operational taxonomic units were enriched in the SCI animal group and three were identified at species level; Lactobacillus intestinalis, Clostridium disporicum, and Bifidobacterium choerinum. In contrast, Clostridium saccharogumia was identified as depleted in the SCI animal group. Proinflammatory cytokines interleukin (IL)-12, macrophage inflammatory protein-2 (MIP-2), and tumor necrosis factor alpha were found to be significantly elevated in intestinal tissue homogenate 4 weeks post-SCI compared to 8-weeks post-injury. Further, levels of IL-1β, IL-12, and MIP-2 significantly correlated with changes in beta diversity 8-weeks post-SCI. Our data provide a greater understanding of the early effects of SCI on the microbiota and gastrointestinal tract, highlighting the need for further investigation to elucidate the mechanism underlying these effects.

The Role of Scientific Communication Skills in Trainees' Intention to Pursue Biomedical Research Careers: A Social Cognitive Analysis.

PubMed

Cameron, Carrie; Lee, Hwa Young; Anderson, Cheryl; Byars-Winston, Angela; Baldwin, Constance D; Chang, Shine

2015-01-01

Scientific communication (SciComm) skills are indispensable for success in biomedical research, but many trainees may not have fully considered the necessity of regular writing and speaking for research career progression. Our purpose was to investigate the relationship between SciComm skill acquisition and research trainees' intentions to remain in research careers. We used social cognitive career theory (SCCT) to test a model of the relationship of SciComm skills to SciComm-related cognitive variables in explaining career intentions. A sample of 510 graduate students and postdoctoral fellows at major academic health science centers in the Texas Medical Center, Houston, Texas, were surveyed online. Results suggested that interest in performing SciComm tasks, SciComm outcome expectations (SCOEs), and SciComm productivity predicted intention to remain in a research career, while SciComm self-efficacy did not directly predict career intention. SCOEs also predicted interest in performing SciComm tasks. As in other SCCT studies, SciComm self-efficacy predicted SCOEs. We conclude that social cognitive factors of SciComm skill acquisition and SciComm productivity significantly predict biomedical trainees' intentions to pursue research careers whether within or outside academia. While further studies are needed, these findings may lead to evidence-based interventions to help trainees remain in their chosen career paths. © 2015 C. Cameron et al. CBE—Life Sciences Education © 2015 The American Society for Cell Biology. This article is distributed by The American Society for Cell Biology under license from the author(s). It is available to the public under an Attribution–Noncommercial–Share Alike 3.0 Unported Creative Commons License (http://creativecommons.org/licenses/by-nc-sa/3.0).

An efficient and accurate approach to MTE-MART for time-resolved tomographic PIV

NASA Astrophysics Data System (ADS)

Lynch, K. P.; Scarano, F.

2015-03-01

The motion-tracking-enhanced MART (MTE-MART; Novara et al. in Meas Sci Technol 21:035401, 2010) has demonstrated the potential to increase the accuracy of tomographic PIV by the combined use of a short sequence of non-simultaneous recordings. A clear bottleneck of the MTE-MART technique has been its computational cost. For large datasets comprising time-resolved sequences, MTE-MART becomes unaffordable and has been barely applied even for the analysis of densely seeded tomographic PIV datasets. A novel implementation is proposed for tomographic PIV image sequences, which strongly reduces the computational burden of MTE-MART, possibly below that of regular MART. The method is a sequential algorithm that produces a time-marching estimation of the object intensity field based on an enhanced guess, which is built upon the object reconstructed at the previous time instant. As the method becomes effective after a number of snapshots (typically 5-10), the sequential MTE-MART (SMTE) is most suited for time-resolved sequences. The computational cost reduction due to SMTE simply stems from the fewer MART iterations required for each time instant. Moreover, the method yields superior reconstruction quality and higher velocity field measurement precision when compared with both MART and MTE-MART. The working principle is assessed in terms of computational effort, reconstruction quality and velocity field accuracy with both synthetic time-resolved tomographic images of a turbulent boundary layer and two experimental databases documented in the literature. The first is the time-resolved data of flow past an airfoil trailing edge used in the study of Novara and Scarano (Exp Fluids 52:1027-1041, 2012); the second is a swirling jet in a water flow. In both cases, the effective elimination of ghost particles is demonstrated in number and intensity within a short temporal transient of 5-10 frames, depending on the seeding density. The increased value of the velocity space-time correlation coefficient demonstrates the increased velocity field accuracy of SMTE compared with MART.

Turbulent motion of mass flows. Mathematical modeling

NASA Astrophysics Data System (ADS)

Eglit, Margarita; Yakubenko, Alexander; Yakubenko, Tatiana

2016-04-01

New mathematical models for unsteady turbulent mass flows, e.g., dense snow avalanches and landslides, are presented. Such models are important since most of large scale flows are turbulent. In addition to turbulence, the two other important points are taken into account: the entrainment of the underlying material by the flow and the nonlinear rheology of moving material. The majority of existing models are based on the depth-averaged equations and the turbulent character of the flow is accounted by inclusion of drag proportional to the velocity squared. In this paper full (not depth-averaged) equations are used. It is assumed that basal entrainment takes place if the bed friction equals the shear strength of the underlying layer (Issler D, M. Pastor Peréz. 2011). The turbulent characteristics of the flow are calculated using a three-parameter differential model (Lushchik et al., 1978). The rheological properties of moving material are modeled by one of the three types of equations: 1) Newtonian fluid with high viscosity, 2) power-law fluid and 3) Bingham fluid. Unsteady turbulent flows down long homogeneous slope are considered. The flow dynamical parameters and entrainment rate behavior in time as well as their dependence on properties of moving and underlying materials are studied numerically. REFERENCES M.E. Eglit and A.E. Yakubenko, 2014. Numerical modeling of slope flows entraining bottom material. Cold Reg. Sci. Technol., 108, 139-148 Margarita E. Eglit and Alexander E. Yakubenko, 2016. The effect of bed material entrainment and non-Newtonian rheology on dynamics of turbulent slope flows. Fluid Dynamics, 51(3) Issler D, M. Pastor Peréz. 2011. Interplay of entrainment and rheology in snow avalanches; a numerical study. Annals of Glaciology, 52(58), 143-147 Lushchik, V.G., Paveliev, A.A. , and Yakubenko, A.E., 1978. Three-parameter model of shear turbulence. Fluid Dynamics, 13, (3), 350-362

Hydrophilic PEO-PDMS for microfluidic applications

NASA Astrophysics Data System (ADS)

Yao, Mingjin; Fang, Ji

2012-02-01

Polydimethylsiloxane (PDMS) is a popularly used nontoxic and biocompatible material in microfluidic systems, which is relatively cheap and does not break easily like glass. The simple fabrication, optical transparency and elastomeric property make PDMS a handy material to work with. In order to develop different applications of PDMS in microfluidics and bioengineering, it is necessary to modify the PDMS surface nature to improve wetting characteristics, and to have a better control in nonspecific binding of proteins and cells, as well as to increase adhesion. At the moment, the hydrophilic surface modification performance of PDMS is known to recover its hydrophobicity shortly after oxidation modification, which is not stable in the long term (Owen and Smith 1994 J. Adhes. Sci. Technol. 8 1063-75). This paper presents a long-term stable hydrophilic surface modification processing of PDMS. The poly(dimethylsiloxane-ethylene oxide polymeric) (PDMS-b-PEO) is used in this project as a surfactant additive to be added into the PDMS base and the curing agent mixture during polymerization and to create hydrophilic PEO-PDMS. The contact angle can be controlled at 21.5-80.9° with the different mixing ratios and the hydrophilicity will remain stable for two months and then slightly varied later. We also investigate the bonding conditions of the modified PDMS to a silicon wafer and a glass wafer. To demonstrate its applications, we designed a device which consists of microchannels on a silicon wafer, and PEO-PDMS is utilized as a cover sheet. The capillary function was investigated under the different contact angles of PED-PDMS and with different aspect ratios of microchannels. All of the processes and testing data are presented in detail. This easy and cost-effective modified PDMS with a good bonding property can be widely used in the capillary device and systems, and microfluidic devices for fluid flow control of the microchannels in biological, chemical, medical applications.

The electrical resistivity of rough thin films: A model based on electron reflection at discrete step edges

NASA Astrophysics Data System (ADS)

Zhou, Tianji; Zheng, Pengyuan; Pandey, Sumeet C.; Sundararaman, Ravishankar; Gall, Daniel

2018-04-01

The effect of the surface roughness on the electrical resistivity of metallic thin films is described by electron reflection at discrete step edges. A Landauer formalism for incoherent scattering leads to a parameter-free expression for the resistivity contribution from surface mound-valley undulations that is additive to the resistivity associated with bulk and surface scattering. In the classical limit where the electron reflection probability matches the ratio of the step height h divided by the film thickness d, the additional resistivity Δρ = √{3 /2 } /(g0d) × ω/ξ, where g0 is the specific ballistic conductance and ω/ξ is the ratio of the root-mean-square surface roughness divided by the lateral correlation length of the surface morphology. First-principles non-equilibrium Green's function density functional theory transport simulations on 1-nm-thick Cu(001) layers validate the model, confirming that the electron reflection probability is equal to h/d and that the incoherent formalism matches the coherent scattering simulations for surface step separations ≥2 nm. Experimental confirmation is done using 4.5-52 nm thick epitaxial W(001) layers, where ω = 0.25-1.07 nm and ξ = 10.5-21.9 nm are varied by in situ annealing. Electron transport measurements at 77 and 295 K indicate a linear relationship between Δρ and ω/(ξd), confirming the model predictions. The model suggests a stronger resistivity size effect than predictions of existing models by Fuchs [Math. Proc. Cambridge Philos. Soc. 34, 100 (1938)], Sondheimer [Adv. Phys. 1, 1 (1952)], Rossnagel and Kuan [J. Vac. Sci. Technol., B 22, 240 (2004)], or Namba [Jpn. J. Appl. Phys., Part 1 9, 1326 (1970)]. It provides a quantitative explanation for the empirical parameters in these models and may explain the recently reported deviations of experimental resistivity values from these models.

Structures of dynamic particle accumulation in Marangoni convection in half-zone liquid bridge

NASA Astrophysics Data System (ADS)

Tanaka, S.; Ueno, I.; Kawamura, H.

Thermocapillary convection is induced by the temperature difference T between two cylindrical rods sustaining liquid bridge. It is well known that the induced flow exhibits a transition from 2-D steady to 3-D time-dependent oscillatory flows with the increasing T. These convections can be visualized by using fine particles as tracers. In a certain flow condition, the particles were found to get accumulated. This is called PAS, particle accumulation structure, after Schwabe et al. (Microgravity, sci. technol. 1996). The authors group (Ueno et al, Proc. TSFP-2, 2001) categorized the induced flow fields into several regimes by the particle motion, structures and the surface temperature variation. Two sets of pulsating and rotating flows appeared. It was observed clearly that the particle gathered along a closed single path. This kind of structure was named as TL-PAS, Twisted-loop particle accumulation structure, (Tanaka et al, J. Japan Soc. Microgravity Appl, 2000). Special attention was paid for this kind of PAS in this study. The TL-PAS exhibited several types of closed path lines. Its detailed structure changed even in the same regime with a slight change of T and aspect ratio. The experimental setup consisted of the transparent crystal top and aluminum bottom rods. Flow fields were observed from top and side through two CCD cameras. A laser-light-sheet was employed in order to grasp the 3-D structures of TL-PAS. The liquid bridge of Silicone oil of 2 cSt was formed between rods of 5mm in diameter. Several kinds of particles were tested as tracer. The surface temperature variation was measured simultaneously by use of a 25μm thermocouple up to 50Hz, or 2.5μm CCT probe (constant current thermometry) up to 100Hz. By use of this apparatus, 3-D structure of TL-PAS and motions of individual particles were captured.

Seasonal Influences on Ground-Surface Water Interactions in an Arsenic-Affected Aquifer in Cambodia

NASA Astrophysics Data System (ADS)

Richards, L. A.; Magnone, D.; Van Dongen, B.; Bryant, C.; Boyce, A.; Ballentine, C. J.; Polya, D. A.

2015-12-01

Millions of people in South and Southeast Asia consume drinking water daily which contains dangerous levels of arsenic exceeding health-based recommendations [1]. A key control on arsenic mobilization in aquifers in these areas has been controversially identified as the interaction of 'labile' organic matter contained in surface waters with groundwaters and sediments at depth [2-4], which may trigger the release of arsenic from the solid- to aqueous-phase via reductive dissolution of iron-(hyr)oxide minerals [5]. In a field site in Kandal Province, Cambodia, which is an arsenic-affected area typical to others in the region, there are strong seasonal patterns in groundwater flow direction, which are closely related to monsoonal rains [6] and may contribute to arsenic release in this aquifer. The aim of this study is to explore the implications of the high susceptibility of this aquifer system to seasonal changes on potential ground-surface water interactions. The main objectives are to (i) identify key zones where there are likely ground-surface water interactions, (ii) assess the seasonal impact of such interactions and (iii) quantify the influence of interactions using geochemical parameters (such as As, Fe, NO3, NH4, 14C, 3T/3He, δ18O, δ2H). Identifying the zones, magnitude and seasonal influence of ground-surface water interactions elucidates new information regarding potential locations/pathways of arsenic mobilization and/or transport in affected aquifers and may be important for water management strategies in affected areas. This research is supported by NERC (NE/J023833/1) to DP, BvD and CJB and a NERC PhD studentship (NE/L501591/1) to DM. References: [1] World Health Organization, 2008. [2] Charlet & Polya (2006), Elements, 2, 91-96. [3] Harvey et al. (2002), Science, 298, 1602-1606. [4] Lawson et al. (2013), Env. Sci. Technol. 47, 7085 - 7094. [5] Islam et al. (2004), Nature, 430, 68-71. [6] Benner et al. (2008) Appl. Geochem. 23(11), 3072 - 3087.

Planar laser imaging of differential molecular diffusion in gas-phase turbulent jets

NASA Astrophysics Data System (ADS)

Brownell, C. J.; Su, L. K.

2008-03-01

Planar laser Rayleigh scattering yields quantitative, two-dimensional measurements of differential diffusion in a turbulent propane-helium jet issuing into air. The jet exit Reynolds number ranges from 1000 to 3000, corresponding to estimated outer-scale Reynolds numbers from 4300 to 13 000. Using a technique originally proposed by Bilger and Dibble [Combust. Sci. Technol. 28, 161 (1982)], the imaging measurements allow direct determination of a normalized scalar difference quantity ξ. For the lower Re, significant differential diffusion develops in the pretransitional portion of the flow. Downstream of the turbulent transition, radial profiles of mean ξ take on a characteristic form, with an excess of the less-diffusive propane on the jet boundary. This characteristic form is independent of Reynolds number, and is thus apparently independent of the degree of differential diffusion in the pretransition range. Evolution of the ξ fields in the turbulent part of the flow is surprisingly consistent with the mixing of conventional scalar quantities. Fluctuation profiles of ξ have a self-similar, bimodal shape for each Re, and power spectra of ξ are monotonically decreasing, with a distinct k-5/3 inertial range. This spectral form is at odds with prior analytical and computational results in isotropic turbulence, which predicted that the spectrum would show a peak intermediate between the diffusive cutoffs of the individual scalars. The discrepancy appears to be due to the forcing applied in the simulations; the differential diffusion in the experiments preferentially develops in the jet near field, so the resulting evolution is more akin to a decay process. This is further emphasized by the observation that the thickness of ξ structures in the jet decreases with downstream distance. The present results indicate that consideration of differential diffusion must account for the details of the flow configuration, particularly the uniformity of turbulence levels. This has important implications for reacting flows, where local laminarization by heat release can be significant.

Dose Accuracy and Injection Force of Different Insulin Glargine Pens

PubMed Central

Friedrichs, Arnd; Bohnet, Janine; Korger, Volker; Adler, Steffen; Schubert-Zsilavecz, Manfred; Abdel-Tawab, Mona

2013-01-01

Background Dose accuracy and injection force, representing key parameters of insulin pens, were determined for three pens delivering insulin glargine-based copies, Pen Royale (WR) and DispoPen (WD) for Glaritus® (Wockhardt) and GanLee Pen (GL) for Basalin® (Gan & Lee), compared with pens of the originator, ClikSTAR® (CS) and S o l o S TA R® (SS) for Lantus® (Sanofi) . Methods Using the weighing procedure recommended by DIN EN ISO 11608–1:2000, dose accuracy was evaluated based on nonrandomized delivery of low (5 U), mid (30 U), and high (60 U) dosage levels. Injection force was measured by dispensing the maximum dose of insulin (60 U for the GL, WR, and WD; 80 U for the SS and CS) at dose speeds of 6 and 10 U/s. Results All tested pens delivered comparable average doses within the DIN EN ISO 11608–1:2000 limits at all dosage levels. The GL revealed a higher coefficient of variation (CV) at 5 U, and the WR and WD had higher CVs at all dosage levels compared with the CS and SS. Injection force was higher for the WR, WD, and GL compared with the CS and SS at both dose speeds. In contrast to the CS and SS with an end-of-content feature, doses exceeding the remaining insulin could be dialed with the WR, GL, and WD and, apparently, dispensed with the WD. Conclusions All pens fulfilled the dose accuracy requirements defined by DIN EN ISO 11608–1:2000 standards at all three dosage levels, with the WR, WD, and GL showing higher dosage variability and injection force compared with the SS and CS. Thus, the devices that deliver insulin glargine copies show different performance characteristics compared with the originator. J Diabetes Sci Technol 2013;7(5):1346–1353 PMID:24124963

Towards improved photovoltaic conversion using dilute magnetic semiconductors (abstract only)

NASA Astrophysics Data System (ADS)

Olsson, Pär; Guillemoles, J.-F.; Domain, C.

2008-02-01

Present photovoltaic devices, based on p/n junctions, are limited from first principles to maximal efficiencies of 31% (40% under full solar concentration; Shockley and Queisser 1961 J. Appl. Phys. 32 510). However, more innovative schemes may overcome the Shockley-Queisser limit since the theoretical maximal efficiency of solar energy conversion is higher than 85% (Harder and Würfel 2003 Semicond. Sci. Technol. 18 S151). To date, the only practical realization of such an innovative scheme has been multi-junction devices, which at present hold the world record for efficiency at nearly 41% at significant solar concentration (US DOE news site: http://www.energy.gov/news/4503.htm). It has been proposed that one could make use of the solar spectrum in much the same way as the multi-junction devices do but in a single cell, using impurity induced intermediate levels to create gaps of different sizes. This intermediate level semiconductor (ILSC) concept (Green and Wenham 1994 Appl. Phys. Lett. 65 2907; Luque and Martí1997 Phys. Rev. Lett. 78 5014) has a maximal efficiency similar to that of multi-junction devices but suffers from prohibitively large non-radiative recombination rates. We here propose to use a ferromagnetic impurity scheme in order to reduce the non-radiative recombination rates while maintaining the high theoretical maximum efficiency of the ILSC scheme, that is about 46%. Using density functional theory calculations, the electronic and energetic properties of transition metal impurities for a wide range of semiconductors have been analysed. Of the several hundred compounds studied, only a few fulfil the design criteria that we present here. As an example, wide gap AlP is one of the most promising compounds. It was found that inclusion of significant amounts of Mn in AlP induces band structures providing conversion efficiencies potentially close to the theoretical maximum, with an estimated Curie temperature reaching above 100 K.