Science.gov

Sample records for addition fundamental studies

  1. A fundamental study of the oxidation behavior of SI primary reference fuels with propionaldehyde and DTBP as an additive

    NASA Astrophysics Data System (ADS)

    Johnson, Rodney

    In an effort to combine the benefits of SI and CI engines, Homogeneous Charge Compression Ignition (HCCI) engines are being developed. HCCI combustion is achieved by controlling the temperature, pressure, and composition of the fuel and air mixture so that autoignition occurs in proper phasing with the piston motion. This control system is fundamentally more challenging than using a spark plug or fuel injector to determine ignition timing as in SI and CI engines, respectively. As a result, this is a technical barrier that must be overcome to make HCCI engines applicable to a wide range of vehicles and viable for high volume production. One way to tailor the autoignition timing is to use small amounts of ignition enhancing additives. In this study, the effect of the addition of DTBP and propionaldehyde on the autoignition behavior of SI primary reference fuels was investigated. The present work was conducted in a new research facility built around a single cylinder Cooperative Fuels Research (CFR) octane rating engine but modified to run in HCCI mode. It focused on the effect of select oxygenated hydrocarbons on hydrocarbon fuel oxidation, specifically, the primary reference fuels n-heptane and iso-octane. This work was conducted under HCCI operating conditions. Previously, the operating parameters for this engine were validated for stable combustion under a wide range of operating parameters such as engine speeds, equivalence ratios, compression ratios and inlet manifold temperature. The stable operating range under these conditions was recorded and used for the present study. The major focus of this study was to examine the effect of the addition of DTBP or propionaldehyde on the oxidation behavior of SI primary reference fuels. Under every test condition the addition of the additives DTBP and propionaldehyde caused a change in fuel oxidation. DTBP always promoted fuel oxidation while propionaldehyde promoted oxidation for lower octane number fuels and delayed

  2. Fundamental studies in geodynamics

    NASA Technical Reports Server (NTRS)

    Anderson, D. L.; Hager, B. H.; Kanamori, H.

    1981-01-01

    Research in fundamental studies in geodynamics continued in a number of fields including seismic observations and analysis, synthesis of geochemical data, theoretical investigation of geoid anomalies, extensive numerical experiments in a number of geodynamical contexts, and a new field seismic volcanology. Summaries of work in progress or completed during this report period are given. Abstracts of publications submitted from work in progress during this report period are attached as an appendix.

  3. Fundamental studies in geodynamics

    NASA Technical Reports Server (NTRS)

    Anderson, D. L.

    1980-01-01

    Progress in modeling instantaneous plate kinematics is reviewed, with emphasis on recently developed models of present day plate motions derived by the systematic inversion of globally distributed data sets. Rivera plate motions, the Caribbean South American boundary, Indian plate deformation, Pacific-North America, seismicity and subduction processes, and the study of slow earthquakes and free oscillations are discussed.

  4. Fundamental Aspects of Selective Melting Additive Manufacturing Processes

    SciTech Connect

    van Swol, Frank B.; Miller, James E.

    2014-12-01

    Certain details of the additive manufacturing process known as selective laser melting (SLM) affect the performance of the final metal part. To unleash the full potential of SLM it is crucial that the process engineer in the field receives guidance about how to select values for a multitude of process variables employed in the building process. These include, for example, the type of powder (e.g., size distribution, shape, type of alloy), orientation of the build axis, the beam scan rate, the beam power density, the scan pattern and scan rate. The science-based selection of these settings con- stitutes an intrinsically challenging multi-physics problem involving heating and melting a metal alloy, reactive, dynamic wetting followed by re-solidification. In addition, inherent to the process is its considerable variability that stems from the powder packing. Each time a limited number of powder particles are placed, the stacking is intrinsically different from the previous, possessing a different geometry, and having a different set of contact areas with the surrounding particles. As a result, even if all other process parameters (scan rate, etc) are exactly the same, the shape and contact geometry and area of the final melt pool will be unique to that particular configuration. This report identifies the most important issues facing SLM, discusses the fundamental physics associated with it and points out how modeling can support the additive manufacturing efforts.

  5. Fundamental studies of fusion plasmas

    SciTech Connect

    Aamodt, R.E.; Catto, P.J.; D'Ippolito, D.A.; Myra, J.R.; Russell, D.A.

    1992-05-26

    The major portion of this program is devoted to critical ICH phenomena. The topics include edge physics, fast wave propagation, ICH induced high frequency instabilities, and a preliminary antenna design for Ignitor. This research was strongly coordinated with the world's experimental and design teams at JET, Culham, ORNL, and Ignitor. The results have been widely publicized at both general scientific meetings and topical workshops including the speciality workshop on ICRF design and physics sponsored by Lodestar in April 1992. The combination of theory, empirical modeling, and engineering design in this program makes this research particularly important for the design of future devices and for the understanding and performance projections of present tokamak devices. Additionally, the development of a diagnostic of runaway electrons on TEXT has proven particularly useful for the fundamental understanding of energetic electron confinement. This work has led to a better quantitative basis for quasilinear theory and the role of magnetic vs. electrostatic field fluctuations on electron transport. An APS invited talk was given on this subject and collaboration with PPPL personnel was also initiated. Ongoing research on these topics will continue for the remainder fo the contract period and the strong collaborations are expected to continue, enhancing both the relevance of the work and its immediate impact on areas needing critical understanding.

  6. Fundamental studies and development of nickel-catalyzed trifluoromethylthiolation of aryl chlorides: active catalytic species and key roles of ligand and traceless MeCN additive revealed.

    PubMed

    Yin, Guoyin; Kalvet, Indrek; Englert, Ulli; Schoenebeck, Franziska

    2015-04-01

    A catalytic protocol to convert aryl and heteroaryl chlorides to the corresponding trifluoromethyl sulfides is reported herein. It relies on a relatively inexpensive Ni(cod)2/dppf (cod = 1,5-cyclooctadiene; dppf = 1,1'-bis(diphenylphosphino)ferrocene) catalyst system and the readily accessible coupling reagent (Me4N)SCF3. Our computational and experimental mechanistic data are consistent with a Ni(0)/Ni(II) cycle and inconsistent with Ni(I) as the reactive species. The relevant intermediates were prepared, characterized by X-ray crystallography, and tested for their catalytic competence. This revealed that a monomeric tricoordinate Ni(I) complex is favored for dppf and Cl whose role was unambiguously assigned as being an off-cycle catalyst deactivation product. Only bidentate ligands with wide bite angles (e.g., dppf) are effective. These bulky ligands render the catalyst resting state as [(P-P)Ni(cod)]. The latter is more reactive than Ni(P-P)2, which was found to be the resting state for ligands with smaller bite angles and suffers from an initial high-energy dissociation of one ligand prior to oxidative addition, rendering the system unreactive. The key to effective catalysis is hence the presence of a labile auxiliary ligand in the catalyst resting state. For more challenging substrates, high conversions were achieved via the employment of MeCN as a traceless additive. Mechanistic data suggest that its beneficial role lies in decreasing the energetic span, therefore accelerating product formation. Finally, the methodology has been applied to synthetic targets of pharmaceutical relevance. PMID:25790253

  7. Fundamental studies of catalytic gasification

    SciTech Connect

    Heinemann, H.; Somorjai, G.A.

    1990-06-01

    Previous work has shown that chars and coal can be gasified with steam in the presence of alkali-transition metal oxide catalysts or alkali-earth alkali catalysts at relatively low temperatures. These studies are to be extended to the investigation of the amounts of catalysts required and whether a throw away catalyst can be used. Fresh versus stored char will be gasified to determine the role of oxidation of the char on gasification rates. Less expensive catalyst materials such as sodium instead of potassium and iron instead of nickel will be explored. Reaction rates will be determined in the presence of nitrogen, Co and CO{sub 2}. Reactions of methane and carbon solids in the presence of an oxidizing agent such as water, oxygen, and/or carbon dioxide will be explored in the presence of similar catalyst. This quarter, additional experiments on catalytic gasification of coal were carried out. Major emphasis, however, was on the production of C{sub 2} and higher hydrocarbons from methane at very high selectivities. Catalysts studied include KCaNiO. 6 figs., 1 tab.

  8. Fundamental studies of polymer filtration

    SciTech Connect

    Smith, B.F.; Lu, M.T.; Robison, T.W.; Rogers, Y.C.; Wilson, K.V.

    1998-12-31

    This is the final report of a one-year, Laboratory Directed Research and Development (LDRD) project at Los Alamos National Laboratory (LANL). The objectives of this project were (1) to develop an enhanced fundamental understanding of the coordination chemistry of hazardous-metal-ion complexation with water-soluble metal-binding polymers, and (2) to exploit this knowledge to develop improved separations for analytical methods, metals processing, and waste treatment. We investigated features of water-soluble metal-binding polymers that affect their binding constants and selectivity for selected transition metal ions. We evaluated backbone polymers using light scattering and ultrafiltration techniques to determine the effect of pH and ionic strength on the molecular volume of the polymers. The backbone polymers were incrementally functionalized with a metal-binding ligand. A procedure and analytical method to determine the absolute level of functionalization was developed and the results correlated with the elemental analysis, viscosity, and molecular size.

  9. The Fundamental Ontology of Study

    ERIC Educational Resources Information Center

    Lewis, Tyson E.

    2014-01-01

    In an effort to disrupt the hegemonic dominance of learning theory, in this article Tyson Lewis explores the unique educational logic of studying. Drawing on the work of Giorgio Agamben, we can understand the operation of study as one of suspension through three modes: preferring not; no longer, not yet; and as not. But the relationship between…

  10. Fundamental studies of catalytic gasification

    SciTech Connect

    Heinemann, H.; Somorjai, G.A.

    1991-09-01

    In this project a considerable number of important findings have been made. Leads for scale-up have been developed and mechanisms for the reaction have been delineated. A small amount of additional experimental work is necessary and the extensive body of this project must be summarized in a final report. Recently limited experimentation has been carried out on the production of C{sub 2} hydrocarbons from methane in the presence of Ca/K/Ni oxide catalysts and of oxygen, carbon and water. The main finding thus far has been that C{sub 2} yields of 10--13% can be obtained at about 600{degrees}C or 150{degrees} lower temperature than described in the literature for similar yields. Occasionally much higher yields were obtained and reasons for this must be determined. We have recently found that with a modified catalyst and by operating at quite low temperature ({approx}600{degrees}C) CO{sub 2} formation can be almost totally suppressed. Yields of 7--10% C{sub 2} hydrocarbons at 99+% selectivity have been obtained. The presence of water and small amounts of oxygen is essential. Yields of this magnitude may be attractive since there is no loss of methane to valueless by-products, no purification of the recycle steam is required and no oxygen is used to burn methane. Further improvement in yields by catalyst and operating conditions modifications will be investigated. It is also intended to clarify the chemistry which inhibits burning of methane to carbon oxides.

  11. Fundamental studies of coal liquefaction

    SciTech Connect

    Ross, D.S.

    1992-12-04

    SRI International is conducting studies of the effects of liquid water at temperatures and pressures near its critical point on the behavior of coal. The present study involves the construction and operation of a cell for visual observation of the process. The cell is batch charged with a dispersion of coal particles in solvent; it is designed for continuous flow operation should that mode of operation become desirable. It can be electrically heated to 550[degree]C and can handle pressures to 5000 psi. Direct observation of individual particles takes place through a pair of diamond windows, a lens assembly, and a television monitoring system. A number of runs have been performed during this quarter, including runs with Wyodak and Illinois No. 6 coal with both water and tetralin. A video tape of two runs was submitted with a monthly report during this quarter, and a tape with four runs in included with this report. Unfortunately just as our experience with the cell was developing, one of the diamonds cracked and the replacement is not expected before December. Accordingly we have spent some time operating the cell with a single window and front lighting.

  12. Fundamental studies of catalytic gasification

    SciTech Connect

    Heinemann, H.; Somorjai, G.A.

    1990-09-01

    Our previous work has shown that chars and coal can be gasified with steam in the presence of alkali-transition metal oxide catalysts or alkali-earth catalysts at relatively low temperatures. These studies are to be extended to the investigation of the amounts of catalysts required and whether a throw away catalyst can be used. Fresh versus stored char will be gasified to determine the role of oxidation of the char on gasification rates. Less expensive catalyst materials such as sodium instead of potassium and iron instead of nickel will be explored. Reaction rates will be determined in the presence of nitrogen, CO and CO{sub 2}. Reactions of methane and carbon solids in the presence of an oxidizing agent such as water, oxygen, and/or carbon dioxide will be explored in the presence of similar catalysts. It is expected that hydrocarbon liquids and C{sub 2} plus gases will be produced along with hydrogen. These studies will be performed over a wide range of reaction pressures and reaction temperatures in a flow reactor using a GC-MS detector. Pure paraffinic and cyclic hydrocarbons of high carbon to hydrogen ratio will be designed to have an indication of the ease of gasification of different carbonaceous materials. Results on the performance of Na, Cs, and BaO{sub x} as catalysts are briefly discussed. 3 figs.

  13. Fundamental studies of spray combustion

    SciTech Connect

    Li, S.C.; Libby, P.A.; Williams, F.A.

    1997-12-31

    Our research on spray combustion involves both experiment and theory and addresses the characteristics of individual droplets and of sprays in a variety of flows: laminar and turbulent, opposed and impinging. Currently our focus concerns water and fuel sprays in two stage laminar flames, i.e., flames arising, for example from a stream of fuel and oxidizer flowing opposite to an air stream carrying a water spray. Our interest in these flames is motivated by the goals of reducing pollutant emissions and extending the range of stable spray combustion. There remains considerable research to be carried out in order to achieve these goals. Thus far our research on the characteristics of sprays in turbulent flows has been limited to nonreacting jets impinging on a plate but this work will be extended to opposed flows with and without a flame. In the following we discuss details of these studies and our plans for future work.

  14. Fundamental studies of coal liquefaction

    SciTech Connect

    Not Available

    1995-01-01

    The authors have examined the pyrolysis of Argonne samples of Wyodak and Illinois No. 6 coal in argon, undecane, Tetralin, and water. The effects of the pyrolysis on individual particles of coal were monitored visually in a cell with diamond windows capable of operation to temperature and pressures in excess of 500{degrees}C and 3000 psi. The changes in the particles from ambient to 460{degrees}C were recorded in real time on video tape, and images were then taken from the tape record and analyzed. The study showed that in argon both coals developed tars at 350{degrees}-370{degrees}C. The tars then quickly evaporated, leaving core particles remarkably similar in size and shape to the initial particles. These observations suggest that coal does not melt nor become fully liquid when heated. Nor does the softened coal undergo crosslinking to generate coke. Rather the simple loss of volatiles leaves behind the core residue as coke. Contrary to the common view, there appears to be no link between the bond-breaking processes yielding tar and the interaction of the coal with H-donors leading to liquefaction. Water as a medium was surprising in its effect. Both coals began to shrink at 300{degrees}-350{degrees}C, with the effect appearing to be more of an erosion rather than a uniform loss of substance as seen in Tetralin. The Wyodak continued to shrink to 460{degrees}C to about half its initial size. With the Illinois No. 6 coal, however, the process reversed at around 420{degrees}C, and the particles appeared to grow with the evolution of a tar, continuing to 460{degrees}C. The authors submit that this final observation is evidence for hydrothermal synthesis of hydrocarbons at these conditions.

  15. Fundamental studies of coal liquefaction

    SciTech Connect

    Ross, D.S.

    1993-02-04

    The results for the control run for a single particle are shown in Figure 1. The figure, which includes other thermolytic data for Illinois No. 6 coal, shows that the particle was stable in size to around 440[degree]C. At that point it contracted very rapidly to about half its size over the next 15[degrees]. Also shown are data for the same coal from SRI's field ionization mass spectrometer (FIMS), in which case a sample of the coal is heated at 2.5[degrees]C/min from ambient to 500[degrees]C and the effluent is swept into mass spectrometer. The evolution of the coal volatiles is reflected by accumulated ion count with increasing temperature, and is presented in the figure as the fraction of total volatiles. As the figure shows, the abrupt increase in volatility corresponds very closely to the equally abrupt reduction in particle size. The weight average molecular weight profile from the FIMS work is also in the figure, and shows that the coal experiences a simple loss of volatiles of increasing molecular weight up to around 440[degrees]C. At that point pyrolysis and fragmentation come about, reflected in the quick reversal and decline in molecular weight. The high rate of volatility and shrinkage are clearly associated with this second stage in the pyrolytic process. These results are further in line with the account of Eser et al. (1991) who found in studies of Illinois No. 6 coal in a high pressure microdilatometer that the coal contracted by about 40% in the same region of temperature at heating rates of around 20[degrees]C/min. At higher heating rates the contraction was followed by a swelling. Finally, in our cell work we observed the deposition of tar in the diamond windows starting at around 350[degrees]C.

  16. Fundamental Studies of Recombinant Hydrogenases

    SciTech Connect

    Adams, Michael W

    2014-01-25

    This research addressed the long term goals of understanding the assembly and organization of hydrogenase enzymes, of reducing them in size and complexity, of determining structure/function relationships, including energy conservation via charge separation across membranes, and in screening for novel H2 catalysts. A key overall goal of the proposed research was to define and characterize minimal hydrogenases that are produced in high yields and are oxygen-resistant. Remarkably, in spite of decades of research carried out on hydrogenases, it is not possible to readily manipulate or design the enzyme using molecular biology approaches since a recombinant form produced in a suitable host is not available. Such resources are essential if we are to understand what constitutes a “minimal” hydrogenase and design such catalysts with certain properties, such as resistance to oxygen, extreme stability and specificity for a given electron donor. The model system for our studies is Pyrococcus furiosus, a hyperthermophile that grows optimally at 100°C, which contains three different nickel-iron [NiFe-] containing hydrogenases. Hydrogenases I and II are cytoplasmic while the other, MBH, is an integral membrane protein that functions to both evolve H2 and pump protons. Three important breakthroughs were made during the funding period with P. furiosus soluble hydrogenase I (SHI). First, we produced an active recombinant form of SHI in E. coli by the co-expression of sixteen genes using anaerobically-induced promoters. Second, we genetically-engineered P. furiosus to overexpress SHI by an order of magnitude compared to the wild type strain. Third, we generated the first ‘minimal’ form of SHI, one that contained two rather than four subunits. This dimeric form was stable and active, and directly interacted with a pyruvate-oxidizing enzyme with any intermediate electron carrier. The research resulted in five peer-reviewed publications.

  17. Fundamental Characterization Studies of Advanced Photocatalytic Materials

    NASA Astrophysics Data System (ADS)

    Phivilay, Somphonh Peter

    Solar powered photocatalytic water splitting has been proposed as a method for the production of sustainable, non-carbon hydrogen fuel. Although much technological progress has been achieved in recent years in the discovery of advanced photocatalytic materials, the progress in the fundamental scientific understanding of such novel, complex mixed oxide and oxynitride photocatalysts has significantly lagged. One of the major reasons for this slow scientific progress is the limited number of reported surface characterization studies of the complex bulk mixed oxide and oxynitride photocatalyst systems. Although photocatalytic splitting of water by bulk mixed oxide and oxynitride materials involves both bulk (generation of excited electrons and holes) and surface phenomena (reaction of H2O with excited electrons and holes at the surface), the photocatalysis community has almost completely ignored the surface characteristics of such complex bulk photocatalysts and correlates the photocatalytic properties with bulk properties. Some of the most promising photocatalyst systems (NaTaO3, GaN, (Ga1-xZnx)(N1-xOx) and TaON) were investigated to establish fundamental bulk/surface structure photoactivity relationships. The bulk molecular and electronic structures of the photocatalysts were determined with Raman and UV-vis spectroscopy. Photoluminescence (PL) and transient PL spectroscopy were provided insight into how recombination of photogenerated electrons is related to the photocatalysis activity. The chemical states and atomic compositions of the surface region of the photocatalysts were determined with high resolution X-ray photoelectron spectroscopy (˜1-3 nm) and high sensitivity-low energy ion scattering spectroscopy (˜0.3 nm). The new insights obtained from surface characterization clarified the role of La and Ni promoters species for the NaTaO3 photocatalyst system. The La2O3 additive was found to be a structural promoter that stabilizes small NaTaO3 nanoparticles (NPs

  18. [Fundamental ophthalmology: the role of electrophysiological studies].

    PubMed

    Zueva, M V

    2014-01-01

    Studying of functional aspects of eye disease pathogenesis by electrophysiological methods is widely demanded in fundamental ophthalmology. Introduction of modern methods of functional assessment into experimental and clinical projects significantly broadens knowledge of normal and pathological functioning of the visual system and is the basis for further development of new strategies of pathogenetic treatment, diagnostics and expert evaluation. Some problems of ophthalmology, including those that concern age-related macular degeneration, glaucoma, diabetic retinopathy, and other diseases, are considered in the context of how much electrophysiology contributes to their solution. The role of functional examinations of the retina in studying pathophysiology of neurodegenerative brain diseases, such as Alzheimer's and Parkinson's, is also discussed. PMID:25715550

  19. Fundamental and Applied Studies of Polymer Membranes

    NASA Astrophysics Data System (ADS)

    Imbrogno, Joseph

    Four major areas have been studied in this research: 1) synthesizing novel monomers, e.g. chiral monomers, to produce new types of functionalized membranes for the biotechnology and pharmaceutical industries, 2) hydrophobic brush membranes for desalinating brackish water, sea water, and separating organics, 3) fundamental studies of water interactions at surfaces using sum frequency generation (SFG), and 4) discovering new surface chemistries that will control the growth and differentiation of stem cells. We have developed a novel synthesis method in order to increase the breadth of our high throughput screening library. This library was generated using maleimide chemistry to react a common methacrylate linker with a variety of different functions groups (R groups) in order to form new monomers that were grafted from the surface of PES ultrafiltration membranes. From this work, we discovered that the chirality of a membrane can affect performance when separating chiral feed streams. This effect was observed when filtering bovine serum albumin (BSA) and ovalbumin in a high salt phosphate buffered saline (PBS, 150 mM salt). The Phe grafted membranes showed a large difference in performance when filtering BSA with selectivity of 1.13 and 1.00 for (S) and (R) Phe, respectively. However, when filtering ovalbumin, the (S) and (R) modified surfaces showed selectivity of 2.06 and 2.31, respectively. The higher selectivity enantiomer switched for the two different proteins. Permeability when filtering BSA was 3.06 LMH kPa-1 and 4.31 LMH kPa -1 for (S)- and (R)- Phe, respectively, and 2.65 LMH kPa -1 and 2.10 LMH kPa-1 when filtering ovalbumin for (S)- and (R)- Phe, respectively. Additionally, these effects were no longer present when using a low salt phosphate buffer (PB, 10 mM salt). Since, to our knowledge, membrane chirality is not considered in current industrial systems, this discovery could have a large impact on the pharmaceutical and biotechnology industries. We

  20. Fundamental and Applied Studies of Polymer Membranes

    NASA Astrophysics Data System (ADS)

    Imbrogno, Joseph

    Four major areas have been studied in this research: 1) synthesizing novel monomers, e.g. chiral monomers, to produce new types of functionalized membranes for the biotechnology and pharmaceutical industries, 2) hydrophobic brush membranes for desalinating brackish water, sea water, and separating organics, 3) fundamental studies of water interactions at surfaces using sum frequency generation (SFG), and 4) discovering new surface chemistries that will control the growth and differentiation of stem cells. We have developed a novel synthesis method in order to increase the breadth of our high throughput screening library. This library was generated using maleimide chemistry to react a common methacrylate linker with a variety of different functions groups (R groups) in order to form new monomers that were grafted from the surface of PES ultrafiltration membranes. From this work, we discovered that the chirality of a membrane can affect performance when separating chiral feed streams. This effect was observed when filtering bovine serum albumin (BSA) and ovalbumin in a high salt phosphate buffered saline (PBS, 150 mM salt). The Phe grafted membranes showed a large difference in performance when filtering BSA with selectivity of 1.13 and 1.00 for (S) and (R) Phe, respectively. However, when filtering ovalbumin, the (S) and (R) modified surfaces showed selectivity of 2.06 and 2.31, respectively. The higher selectivity enantiomer switched for the two different proteins. Permeability when filtering BSA was 3.06 LMH kPa-1 and 4.31 LMH kPa -1 for (S)- and (R)- Phe, respectively, and 2.65 LMH kPa -1 and 2.10 LMH kPa-1 when filtering ovalbumin for (S)- and (R)- Phe, respectively. Additionally, these effects were no longer present when using a low salt phosphate buffer (PB, 10 mM salt). Since, to our knowledge, membrane chirality is not considered in current industrial systems, this discovery could have a large impact on the pharmaceutical and biotechnology industries. We

  1. Fundamentals of free flux flow: proposed studies

    NASA Astrophysics Data System (ADS)

    Alexander, J. A.; Gafarov, O.; Gapud, A. A.; Wu, J. Z.

    2013-03-01

    Although much is known about free flux flow (FFF) in superconductors - in which pinning is insignificant compared to interactions between quantized vortices - there still remain questions concerning fundamental dynamics. Building on our previous work in correlating FFF with vortex core size (PRB 80, 134524), we propose three new studies examining more deeply the normal state in the vortex core and interactions between vortices. A correlation between scattering inside cores and the viscosity of FFF has not been explicitly determined; this may be investigated by probing the effect of scattering centers created by proton irradiation. Using results of previous irradiation work, one could control the extent of normal state scattering while monitoring effects on FFF. Questions also exist concerning vortex motion in channels with widths approaching that of individual vortices - as determined solely by inter-vortex interactions. Studies have suggested that flux flow through constrictions could imitate ``jamming'' in the collective motion of grains: Under certain conditions, it is possible for grains to form a barrier, blocking flow. More than just qualitatively comparing flux flow and granular flow to find evidence of jamming, we propose a new experiment for quantitatively modeling flux jamming by realizing the flux flow equivalent of granular jamming in a ``hopper''. In the same way, we also propose a FFF equivalent of another granular-flow phenomenon, ``non-Newtonian'' fluids, where rapid shear causes jamming. Funded by NSF-RUI grant, DMR-0907038.

  2. A Study of Fundamental Shock Noise Mechanisms

    NASA Technical Reports Server (NTRS)

    Meadows, Kristine R.

    1997-01-01

    This paper investigates two mechanisms fundamental to sound generation in shocked flows: shock motion and shock deformation. Shock motion is modeled numerically by examining the interaction of a sound wave with a shock. This numerical approach is validated by comparison with results obtained by linear theory for a small-disturbance case. Analysis of the perturbation energy with Myers' energy corollary demonstrates that acoustic energy is generated by the interaction of acoustic disturbances with shocks. This analysis suggests that shock motion generates acoustic and entropy disturbance energy. Shock deformation is modeled numerically by examining the interaction of a vortex ring with a shock. These numerical simulations demonstrate the generation of both an acoustic wave and contact surfaces. The acoustic wave spreads cylindrically. The sound intensity is highly directional and the sound pressure increases with increasing shock strength. The numerically determined relationship between the sound pressure and the Mach number is found to be consistent with experimental observations of shock noise. This consistency implies that a dominant physical process in the generation of shock noise is modeled in this study.

  3. Fundamental studies on passivity and passivity breakdown

    SciTech Connect

    Macdonald, D.D.; Urquidi-Macdonald, M.

    1993-06-01

    Using photoelectrochemical impedance and admittance spectroscopies, a fundamental and quantitative understanding of the mechanisms for the growth and breakdown of passive films on metal and alloy surfaces in contact with aqueous environments is being developed. A point defect model has been extended to explain the breakdown of passive films, leading to pitting and crack growth and thus development of damage due to localized corrosion.

  4. Fundamental Ice Crystal Accretion Physics Studies

    NASA Technical Reports Server (NTRS)

    Struk, Peter M.; Broeren, Andy P.; Tsao, Jen-Ching; Vargas, Mario; Wright, William B.; Currie, Tom; Knezevici, Danny; Fuleki, Dan

    2012-01-01

    Due to numerous engine power-loss events associated with high-altitude convective weather, ice accretion within an engine due to ice crystal ingestion is being investigated. The National Aeronautics and Space Administration (NASA) and the National Research Council (NRC) of Canada are starting to examine the physical mechanisms of ice accretion on surfaces exposed to ice-crystal and mixed-phase conditions. In November 2010, two weeks of testing occurred at the NRC Research Altitude Facility utilizing a single wedge-type airfoil designed to facilitate fundamental studies while retaining critical features of a compressor stator blade or guide vane. The airfoil was placed in the NRC cascade wind tunnel for both aerodynamic and icing tests. Aerodynamic testing showed excellent agreement compared with CFD data on the icing pressure surface and allowed calculation of heat transfer coefficients at various airfoil locations. Icing tests were performed at Mach numbers of 0.2 to 0.3, total pressures from 93 to 45 kPa, and total temperatures from 5 to 15 C. Ice and liquid water contents ranged up to 20 and 3 g/m3, respectively. The ice appeared well adhered to the surface in the lowest pressure tests (45 kPa) and, in a particular case, showed continuous leading-edge ice growth to a thickness greater than 15 mm in 3 min. Such widespread deposits were not observed in the highest pressure tests, where the accretions were limited to a small area around the leading edge. The suction surface was typically ice-free in the tests at high pressure, but not at low pressure. The icing behavior at high and low pressure appeared to be correlated with the wet-bulb temperature, which was estimated to be above 0 C in tests at 93 kPa and below 0 C in tests at lower pressure, the latter enhanced by more evaporative cooling of water. The authors believe that the large ice accretions observed in the low pressure tests would undoubtedly cause the aerodynamic performance of a compressor component

  5. Fundamental Ice Crystal Accretion Physics Studies

    NASA Technical Reports Server (NTRS)

    Currie, Tom; Knezevici, Danny; Fuleki, Dan; Struk, Peter M.; Broeren, Andy P.; Tsao, Jen-ching; Vargas, Mario; Wright, William

    2011-01-01

    Due to numerous engine power-loss events associated with high-altitude convective weather, ice accretion within an engine due to ice-crystal ingestion is being investigated. The National Aeronautics and Space Administration (NASA) and the National Research Council (NRC) of Canada are starting to examine the physical mechanisms of ice accretion on surfaces exposed to ice-crystal and mixed-phase conditions. In November 2010, two weeks of testing occurred at the NRC Research Altitude Facility utilizing a single wedge-type airfoil designed to facilitate fundamental studies while retaining critical features of a compressor stator blade or guide vane. The airfoil was placed in the NRC cascade wind tunnel for both aerodynamic and icing tests. Aerodynamic testing showed excellent agreement compared with CFD data on the icing pressure surface and allowed calculation of heat transfer coefficients at various airfoil locations. Icing tests were performed at Mach numbers of 0.2 to 0.3, total pressures from 93 to 45 kPa, and total temperatures from 5 to 15 C. Ice and liquid water contents ranged up to 20 and 3 grams per cubic meter, respectively. The ice appeared well adhered to the surface in the lowest pressure tests (45 kPa) and, in a particular case, showed continuous leading-edge ice growth to a thickness greater than 15 millimeters in 3 minutes. Such widespread deposits were not observed in the highest pressure tests, where the accretions were limited to a small area around the leading edge. The suction surface was typically ice-free in the tests at high pressure, but not at low pressure. The icing behavior at high and low pressure appeared to be correlated with the wet-bulb temperature, which was estimated to be above 0 C in tests at 93 kPa and below 0 C in tests at lower pressure, the latter enhanced by more evaporative cooling of water. The authors believe that the large ice accretions observed in the low pressure tests would undoubtedly cause the aerodynamic

  6. Cable Discharge System for fundamental detonator studies

    NASA Technical Reports Server (NTRS)

    Peevy, Gregg R.; Barnhart, Steven G.; Brigham, William P.

    1994-01-01

    Sandia National Laboratories has recently completed the modification and installation of a cable discharge system (CDS) which will be used to study the physics of exploding bridgewire (EBW) detonators and exploding foil initiators (EFI or slapper). Of primary interest are the burst characteristics of these devices when subjected to the constant current pulse delivered by this system. The burst process involves the heating of the bridge material to a conductive plasma and is essential in describing the electrical properties of the bridgewire foil for use in diagnostics or computer models. The CDS described herein is capable of delivering up to an 8000 A pulse of 3 micron duration. Experiments conducted with the CDS to characterize the EBW and EFI burst behavior are also described. In addition, the CDS simultaneous VISAR capability permits updating the EFI electrical Gurney analysis parameters used in our computer simulation codes. Examples of CDS generated data for a typical EFI and EBW detonator are provided.

  7. Fundamental studies of passivity and passivity breakdown

    SciTech Connect

    Macdonald, D.D.; Urquidi-Macdonald, M.; Song, H.; Biaggio-Rocha, S.; Searson, P.

    1991-11-01

    This report summarizes the findings of our fundamental research program on passivity and passivity breakdown. During the past three and one half years in this program (including the three year incrementally-funded grant prior to the present grant), we developed and experimentally tested various physical models for the growth and breakdown of passive films on metal surfaces. These models belong to a general class termed point defects models'' (PDMs), in which the growth and breakdown of passive films are described in terms of the movement of anion and cation vacancies.

  8. Fundamental studies concerning planetary quarantine in space.

    PubMed

    Koike, J; Hori, T; Katahira, Y; Koike, K A; Tanaka, K; Kobayashi, K; Kawasaki, Y

    1996-01-01

    If there is a possibility that the organisms carried from Earth to space can live for a significant period on planets, the contamination of planets should be prevented for the purpose of future life-detection experiments. In connection with quarantine for interplanetary missions, we have examined the survivabilities of terrestrial microorganisms under simulated space conditions. In this study, examined the survivabilities of terrestrial organisms under simulated Mars conditions. The Mars conditions were simulated by ultraviolet (UV) and proton irradiation under low temperature, high vacuum, and simulated gaseous conditions. After exposure to the simulated Mars condition, the survivabilities of the organisms were examined. The spores of Bacillus subtilis and Aspergillus niger, some anaerobic bacterias and algaes, showed considerably high survivabilities even after UV and proton irradiation corresponding to 200 years on Mars. This subject is not restricted to academic curiosity but concerns problems involving the contamination of Mars with terrestrial organisms carried by space-probes.

  9. Fundamental studies concerning planetary quarantine in space

    NASA Astrophysics Data System (ADS)

    Koike, J.; Hori, T.; Katahira, Y.; Koike, K. A.; Tanaka, K.; Kobayashi, K.; Kawasaki, Y.

    If there is a possibility that the organisms carried from Earth to space can live for a significant period on planets, the contamination of planets should be prevented for the purpose of future life-detection experiments. In connection with quarantine for interplanetary missions, we have examined the survivabilities of terrestrial microorganisms under simulated space conditions /1-8/. In this study, examined the survivabilities of terrestrial organisms under simulated Mars conditions. The Mars conditions were simulated by ultraviolet (UV) and proton irradiation under low temperature, high vacuum, and simulated gaseous conditions. After exposure to the simulated Mars condition, the survivabilities of the organisms were examined. The spores of Bacillus subtilis andAspergillus niger , some anaerobic bacterias and algaes, showed considerably high survivabilities even after UV and proton irradiation corresponding to 200 years on Mars. This subject is not restricted to academic curiosity but concerns problems involving the contamination of Mars with terrestrial organisms carried by space-probes.

  10. Fundamental studies concerning planetary quarantine in space.

    PubMed

    Koike, J; Hori, T; Katahira, Y; Koike, K A; Tanaka, K; Kobayashi, K; Kawasaki, Y

    1996-01-01

    If there is a possibility that the organisms carried from Earth to space can live for a significant period on planets, the contamination of planets should be prevented for the purpose of future life-detection experiments. In connection with quarantine for interplanetary missions, we have examined the survivabilities of terrestrial microorganisms under simulated space conditions. In this study, examined the survivabilities of terrestrial organisms under simulated Mars conditions. The Mars conditions were simulated by ultraviolet (UV) and proton irradiation under low temperature, high vacuum, and simulated gaseous conditions. After exposure to the simulated Mars condition, the survivabilities of the organisms were examined. The spores of Bacillus subtilis and Aspergillus niger, some anaerobic bacterias and algaes, showed considerably high survivabilities even after UV and proton irradiation corresponding to 200 years on Mars. This subject is not restricted to academic curiosity but concerns problems involving the contamination of Mars with terrestrial organisms carried by space-probes. PMID:11538982

  11. Fundamental studies of water pretreatment of coal

    SciTech Connect

    Serio, M.A.; Solomon, P.R.; Kroo, E.; Charpenay, S.; Bassilakis, R.

    1990-01-01

    The goals of this project are to gain understanding of the chemistry of water or steam coal pretreatments and to assess the importance of such pretreatments on subsequent coal liquefaction. Coals, modified coals and model-polymers will be treated with water or steam. This study will include three coals, five modifications (dried, demineralized, ion-exchanged, Ca-loaded, Ba-loaded), three polymers and two polymer modifications (e.g. acid chlorides, amides). Experiments will be performed to investigate both conventional steam pretreatment and the possibility of using the CO/H{sub 2}O system of Ross and coworkers as a pretreatment method. The main experimental variables will be sample type and temperature. Detailed characterization of the gas, liquid and solid products from the pretreatment stage will be done. This will include analysis of gases by GC or FT-IR, liquids by capillary GC, FT-IR and FIMS, and residues by solvent swelling, solvent extraction, and elemental analysis. Selected residues will also be evaluated by a standard liquefaction test. Analysis of the raw coals and pretreatment samples will be performed using the above techniques to study changes in the crosslinking, donatable hydrogen, heteroatom composition, evolved gases, functional group composition, extraction yields, molecular weight distributions, etc. Standard tubing bomb liquefaction tests will be used to determine the effect of pretreatment on coal reactivity toward coal liquefaction. A previously developed model for coal liquefaction, the FG-DVC liquefaction model, will be used (after appropriate modifications) to model the physics and chemistry of water pretreatment. 3 figs., 3 tabs.

  12. Fundamental study on identification of CMOS cameras

    NASA Astrophysics Data System (ADS)

    Kurosawa, Kenji; Saitoh, Naoki

    2003-08-01

    In this study, we discussed individual camera identification of CMOS cameras, because CMOS (complementary-metal-oxide-semiconductor) imaging detectors have begun to make their move into the CCD (charge-coupled-device) fields for recent years. It can be identified whether or not the given images have been taken with the given CMOS camera by detecting the imager's intrinsic unique fixed pattern noise (FPN) just like the individual CCD camera identification method proposed by the authors. Both dark and bright pictures taken with the CMOS cameras can be identified by the method, because not only dark current in the photo detectors but also MOS-FET amplifiers incorporated in each pixel may produce pixel-to-pixel nonuniformity in sensitivity. Each pixel in CMOS detectors has the amplifier, which degrades image quality of bright images due to the nonuniformity of the amplifier gain. Two CMOS cameras were evaluated in our experiments. They were WebCamGoPlus (Creative), and EOS D30 (Canon). WebCamGoPlus is a low-priced web camera, whereas EOS D30 is for professional use. Image of a white plate were recorded with the cameras under the plate's luminance condition of 0cd/m2 and 150cd/m2. The recorded images were multiply integrated to reduce the random noise component. From the images of both cameras, characteristic dots patterns were observed. Some bright dots were observed in the dark images, whereas some dark dots were in the bright images. The results show that the camera identification method is also effective for CMOS cameras.

  13. Fundamental studies of supported bimetallic catalysts by NMR spectroscopy

    SciTech Connect

    Savargaonkar, N.

    1996-10-17

    Various hydrogenation reactions on transition metals are important commercially whereas certain hydrogenolysis reactions are useful from fundamental point of view. Understanding the hydrogen mobility and kinetics of adsorption-desorption of hydrogen is important in understanding the mechanisms of such reactions involving hydrogen. The kinetics of hydrogen chemisorption was studied by means of selective excitation NMR on silica supported Pt, Rh and Pt-Rh catalysts. The activation energy of hydrogen desorption was found to be lower on silica supported Pt catalysts as compared to Rh and Pt-Rh catalysts. It was found that the rates of hydrogen adsorption and desorption on Pt-Rh catalyst were similar to those on Rh catalyst and much higher as compared to Pt catalyst. The Ru-Ag bimetallic system is much simpler to study than the Pt-Rh system and serves as a model system to characterize more complicated systems such as the K/Ru system. Ag was found to decrease the amounts of adsorbed hydrogen and the hydrogen-to-ruthenium stoichiometry. Ag reduced the populations of states with low and intermediate binding energies of hydrogen on silica supported Ru catalyst. The rates of hydrogen adsorption and desorption were also lower on silica supported Ru-Ag catalyst as compared to Ru catalyst. This report contains introductory information, the literature review, general conclusions, and four appendices. An additional four chapters and one appendix have been processed separately for inclusion on the data base.

  14. A Course of Study in Acting Fundamentals for Junior College.

    ERIC Educational Resources Information Center

    Greening, Ruth Patricia Browne

    A complete and comprehensive course of study in acting fundamentals for the junior college is presented. Its overall goals are to develop individual sensitivity and creativity, without neglecting essential skills and traditional theatrical and academic values. Justification of major course objectives in the junior college curriculum, presentation…

  15. Fourier, Gegenbauer and Jacobi Expansions for a Power-Law Fundamental Solution of the Polyharmonic Equation and Polyspherical Addition Theorems

    NASA Astrophysics Data System (ADS)

    Cohl, Howard S.

    2013-06-01

    We develop complex Jacobi, Gegenbauer and Chebyshev polynomial expansions for the kernels associated with power-law fundamental solutions of the polyharmonic equation on d-dimensional Euclidean space. From these series representations we derive Fourier expansions in certain rotationally-invariant coordinate systems and Gegenbauer polynomial expansions in Vilenkin's polyspherical coordinates. We compare both of these expansions to generate addition theorems for the azimuthal Fourier coefficients.

  16. Unraveling the Fundamental Mechanisms of Solvent-Additive-Induced Optimization of Power Conversion Efficiencies in Organic Photovoltaic Devices.

    PubMed

    Herath, Nuradhika; Das, Sanjib; Zhu, Jiahua; Kumar, Rajeev; Chen, Jihua; Xiao, Kai; Gu, Gong; Browning, James F; Sumpter, Bobby G; Ivanov, Ilia N; Lauter, Valeria

    2016-08-10

    The realization of controllable morphologies of bulk heterojunctions (BHJ) in organic photovoltaics (OPVs) is one of the key factors enabling high-efficiency devices. We provide new insights into the fundamental mechanisms essential for the optimization of power conversion efficiencies (PCEs) with additive processing to PBDTTT-CF:PC71BM system. We have studied the underlying mechanisms by monitoring the 3D nanostructural modifications in BHJs and correlated the modifications with the optical analysis and theoretical modeling of charge transport. Our results demonstrate profound effects of diiodooctane (DIO) on morphology and charge transport in the active layers. For small amounts of DIO (<3 vol %), DIO promotes the formation of a well-mixed donor-acceptor compact film and augments charge transfer and PCE. In contrast, for large amounts of DIO (>3 vol %), DIO facilitates a loosely packed mixed morphology with large clusters of PC71BM, leading to deterioration in PCE. Theoretical modeling of charge transport reveals that DIO increases the mobility of electrons and holes (the charge carriers) by affecting the energetic disorder and electric field dependence of the mobility. Our findings show the implications of phase separation and carrier transport pathways to achieve optimal device performances. PMID:27403964

  17. Unraveling the Fundamental Mechanisms of Solvent-Additive-Induced Optimization of Power Conversion Efficiencies in Organic Photovoltaic Devices.

    PubMed

    Herath, Nuradhika; Das, Sanjib; Zhu, Jiahua; Kumar, Rajeev; Chen, Jihua; Xiao, Kai; Gu, Gong; Browning, James F; Sumpter, Bobby G; Ivanov, Ilia N; Lauter, Valeria

    2016-08-10

    The realization of controllable morphologies of bulk heterojunctions (BHJ) in organic photovoltaics (OPVs) is one of the key factors enabling high-efficiency devices. We provide new insights into the fundamental mechanisms essential for the optimization of power conversion efficiencies (PCEs) with additive processing to PBDTTT-CF:PC71BM system. We have studied the underlying mechanisms by monitoring the 3D nanostructural modifications in BHJs and correlated the modifications with the optical analysis and theoretical modeling of charge transport. Our results demonstrate profound effects of diiodooctane (DIO) on morphology and charge transport in the active layers. For small amounts of DIO (<3 vol %), DIO promotes the formation of a well-mixed donor-acceptor compact film and augments charge transfer and PCE. In contrast, for large amounts of DIO (>3 vol %), DIO facilitates a loosely packed mixed morphology with large clusters of PC71BM, leading to deterioration in PCE. Theoretical modeling of charge transport reveals that DIO increases the mobility of electrons and holes (the charge carriers) by affecting the energetic disorder and electric field dependence of the mobility. Our findings show the implications of phase separation and carrier transport pathways to achieve optimal device performances.

  18. New Quasar Studies Keep Fundamental Physical Constant Constant

    NASA Astrophysics Data System (ADS)

    2004-03-01

    Very Large Telescope sets stringent limit on possible variation of the fine-structure constant over cosmological time Summary Detecting or constraining the possible time variations of fundamental physical constants is an important step toward a complete understanding of basic physics and hence the world in which we live. A step in which astrophysics proves most useful. Previous astronomical measurements of the fine structure constant - the dimensionless number that determines the strength of interactions between charged particles and electromagnetic fields - suggested that this particular constant is increasing very slightly with time. If confirmed, this would have very profound implications for our understanding of fundamental physics. New studies, conducted using the UVES spectrograph on Kueyen, one of the 8.2-m telescopes of ESO's Very Large Telescope array at Paranal (Chile), secured new data with unprecedented quality. These data, combined with a very careful analysis, have provided the strongest astronomical constraints to date on the possible variation of the fine structure constant. They show that, contrary to previous claims, no evidence exist for assuming a time variation of this fundamental constant. PR Photo 07/04: Relative Changes with Redshift of the Fine Structure Constant (VLT/UVES) A fine constant To explain the Universe and to represent it mathematically, scientists rely on so-called fundamental constants or fixed numbers. The fundamental laws of physics, as we presently understand them, depend on about 25 such constants. Well-known examples are the gravitational constant, which defines the strength of the force acting between two bodies, such as the Earth and the Moon, and the speed of light. One of these constants is the so-called "fine structure constant", alpha = 1/137.03599958, a combination of electrical charge of the electron, the Planck constant and the speed of light. The fine structure constant describes how electromagnetic forces hold

  19. New Quasar Studies Keep Fundamental Physical Constant Constant

    NASA Astrophysics Data System (ADS)

    2004-03-01

    a function of the redshift and the corresponding look-back time. The open circle is the measurement from the Oklo natural reactor. The horizontal long dashed lines show the area of the previous claim of variation of the fine structure constant. Clearly, the new UVES data are inconsistent with this range. A team of astronomers [1], led by Patrick Petitjean (Institut d'Astrophysique de Paris and Observatoire de Paris, France) and Raghunathan Srianand (IUCAA Pune, India) very carefully studied a homogeneous sample of 50 absorption systems observed with UVES and Kueyen along 18 distant quasars lines of sight. They recorded the spectra of quasars over a total of 34 nights to achieve the highest possible spectral resolution and the best signal-to-noise ratio. Sophisticated automatic procedures specially designed for this programme were applied. In addition, the astronomers used extensive simulations to show that they can correctly model the line profiles to recover a possible variation of alpha. The result of this extensive study is that over the last 10,000 million years, the relative variation of alpha must be less than 0.6 part per million. This is the strongest constraint from quasar absorption lines studies to date. More importantly, this new result does not support previous claims of a statistically significant change of alpha with time. Interestingly, this result is supported by another - less extensive - analysis, also conducted with the UVES spectrometer on the VLT [2]. Even though those observations were only concerned with one of the brightest known quasar HE 0515-4414, this independent study lends further support to the hypothesis of no variation of alpha. Even though these new results represent a significant improvement in our knowledge of the possible (non-) variation of one of the fundamental physical constants, the present set of data would in principle still allow variations that are comparatively large compared to those resulting from the measurements

  20. High-accuracy mass spectrometry for fundamental studies.

    PubMed

    Kluge, H-Jürgen

    2010-01-01

    Mass spectrometry for fundamental studies in metrology and atomic, nuclear and particle physics requires extreme sensitivity and efficiency as well as ultimate resolving power and accuracy. An overview will be given on the global status of high-accuracy mass spectrometry for fundamental physics and metrology. Three quite different examples of modern mass spectrometric experiments in physics are presented: (i) the retardation spectrometer KATRIN at the Forschungszentrum Karlsruhe, employing electrostatic filtering in combination with magnetic-adiabatic collimation-the biggest mass spectrometer for determining the smallest mass, i.e. the mass of the electron anti-neutrino, (ii) the Experimental Cooler-Storage Ring at GSI-a mass spectrometer of medium size, relative to other accelerators, for determining medium-heavy masses and (iii) the Penning trap facility, SHIPTRAP, at GSI-the smallest mass spectrometer for determining the heaviest masses, those of super-heavy elements. Finally, a short view into the future will address the GSI project HITRAP at GSI for fundamental studies with highly-charged ions.

  1. High-accuracy mass spectrometry for fundamental studies.

    PubMed

    Kluge, H-Jürgen

    2010-01-01

    Mass spectrometry for fundamental studies in metrology and atomic, nuclear and particle physics requires extreme sensitivity and efficiency as well as ultimate resolving power and accuracy. An overview will be given on the global status of high-accuracy mass spectrometry for fundamental physics and metrology. Three quite different examples of modern mass spectrometric experiments in physics are presented: (i) the retardation spectrometer KATRIN at the Forschungszentrum Karlsruhe, employing electrostatic filtering in combination with magnetic-adiabatic collimation-the biggest mass spectrometer for determining the smallest mass, i.e. the mass of the electron anti-neutrino, (ii) the Experimental Cooler-Storage Ring at GSI-a mass spectrometer of medium size, relative to other accelerators, for determining medium-heavy masses and (iii) the Penning trap facility, SHIPTRAP, at GSI-the smallest mass spectrometer for determining the heaviest masses, those of super-heavy elements. Finally, a short view into the future will address the GSI project HITRAP at GSI for fundamental studies with highly-charged ions. PMID:20530821

  2. The fundamental physics explorer: An ESA technology reference study

    NASA Astrophysics Data System (ADS)

    Binns, D. A.; Rando, N.; Cacciapuoti, L.

    2009-04-01

    ESA technology reference studies are used as a process to identify key technologies and technical challenges of potential future missions not yet in the science programme. This paper reports on the study of the Fundamental Physics Explorer (FPE), a re-usable platform targeted to small missions testing fundamental laws of physics in space. The study addresses three specific areas of interest: special and general relativity tests based on atomic clocks, experiments on the Weak Equivalence Principle (WEP), and studies of Bose-Einstein condensates under microgravity conditions. Starting from preliminary science objectives and payload requirements, three reference missions in the small/medium class range are discussed, based on a re-adaptation of the LISA Pathfinder spacecraft. A 700/3600 km elliptic orbit has been selected to conduct clock tests of special and general relativity, a 700 km circular orbit to perform experiments on the Weak Equivalence Principle and to study Bose-Einstein condensates, each mission being based on a three-axis stabilised spacecraft. It was determined that adaptation of LISA Pathfinder would be required in order to meet the demands of the FPE missions. Moreover it was established that specific payload and spacecraft technology development would be required to realise such a programme.

  3. Fundamental Mechanistic Investigations of Silane and Chlorocarbon Addition to Low Valent Palladium Species and their Application to Catalysis

    SciTech Connect

    Fink, Mark J.

    2009-01-27

    The collaboration between Mark Fink (Tulane University) and R. Morris Bullock (Brookhaven National Laboratory, currently at PNL) is an effort to understand some of the fundamental processes involved in catalytic bond activations with low coordinate palladium species. The project involves the photochemical generation of reactive low-valent palladium species as transients using nanosecond laser flash photolysis and the subsequent investigation of their reactions with chloroarenes and hydrosilanes. In the case of Si-H activation of hydrosilanes, relatively long-lived sigma complexes are implicated. These complexes may be important models for C-H activation in hydrocarbons. The information obtained from these studies will help in the understanding of fundamental processes involved in a number of important catalytic reactions in the petrochemical and environmental areas.

  4. Fundamental studies on the Cs dynamics under ion source conditions

    SciTech Connect

    Friedl, R. Fantz, U.

    2014-02-15

    The performance of surface conversion based negative hydrogen ion sources is mainly determined by the caesium dynamics. Therefore, fundamental investigations in vacuum and plasma are performed at a flexible laboratory setup with ion source parameters. Studies on the influence of Cs on the plasma parameters of H{sub 2} and D{sub 2} plasmas showed that n{sub e} and T{sub e} in the bulk plasma are not affected by relevant amounts of Cs and no isotopic differences could be observed. The coating of the vessel surfaces with Cs, however, leads to a considerable gettering of hydrogen atoms from the plasma volume and to the decrease of n{sub e} close to a sample surface due to the formation of negative ions.

  5. Fundamental studies of fusion plasmas. Annual performance report

    SciTech Connect

    Aamodt, R.E.; Catto, P.J.; D`Ippolito, D.A.; Myra, J.R.; Russell, D.A.

    1992-05-26

    The major portion of this program is devoted to critical ICH phenomena. The topics include edge physics, fast wave propagation, ICH induced high frequency instabilities, and a preliminary antenna design for Ignitor. This research was strongly coordinated with the world`s experimental and design teams at JET, Culham, ORNL, and Ignitor. The results have been widely publicized at both general scientific meetings and topical workshops including the speciality workshop on ICRF design and physics sponsored by Lodestar in April 1992. The combination of theory, empirical modeling, and engineering design in this program makes this research particularly important for the design of future devices and for the understanding and performance projections of present tokamak devices. Additionally, the development of a diagnostic of runaway electrons on TEXT has proven particularly useful for the fundamental understanding of energetic electron confinement. This work has led to a better quantitative basis for quasilinear theory and the role of magnetic vs. electrostatic field fluctuations on electron transport. An APS invited talk was given on this subject and collaboration with PPPL personnel was also initiated. Ongoing research on these topics will continue for the remainder fo the contract period and the strong collaborations are expected to continue, enhancing both the relevance of the work and its immediate impact on areas needing critical understanding.

  6. Amphitropic liquid crystal phases from polyhydroxy sugar surfactants: Fundamental studies

    NASA Astrophysics Data System (ADS)

    Abou Zied, Osama K.; Hashim, Rauzah; Timimi, B. A.

    2015-03-01

    The self-assembly phenomena on a special class of poly-hydroxy sugar surfactant have been studied extensively. This class of material is classified as amphitropic liquid crystals since they exhibit both thermotropic and lyotropic liquid crystalline properties. Hence the potential applications of these non-ionic surfactants are more versatile than those from the conventional lyotropic liquid crystals including those from thermotropic phases, but the latters are yet to be realized. Unfortunately, due to the lack of interest (or even awareness), fundamental studies in thermotropic glycolipids are scanty to support application development, and any tangible progress is often mired by the complexity of the sugar stereochemistry. However, some applications may be pursued from these materials by taking the advantage of the sugar chirality and the tilted structure of the lipid organization which implies ferroelectric behavior. Here, we present our studies on the stereochemical diversity of the sugar units in glycosides that form the thermotropic/lyotropic phases. The structure to property relationship compares different chain designs and other popular polyhydroxy compounds, such as monooleins and alkylpolyglucosides. Different structural properties of these glycosides are discussed with respect to their self-assembly organization and potential applications, such as delivery systems and membrane mimetic study.

  7. Design, fabrication and fundamental studies of plasmonic materials

    NASA Astrophysics Data System (ADS)

    McLellan, Erin C.

    2007-12-01

    Nanoplasmonics is an emerging branch of photonics that studies the optical properties of noble metals. Nanostructured noble metal materials, which can strongly interact with light and support various plasmon modes, are exceptional candidates for nanophotonic devices. This work describes the latest advances in the fabrication of ordered silver nanoparticles or nanowell arrays using both nanosphere lithography (NSL) and electron beam lithography (EBL). More specifically, three types of new NSL-derived materials are addressed in this thesis: (1) the application of electrochemistry to "fine tune" the structure of silver nanotriangles and the wavelength of their localized surface plasmon resonance (LSPR), (2) the fabrication of ordered arrays of in-plane, triangular cross-section nanowells with the aid of reactive ion etching (RIE), and (3) the anchoring of the truncated tetrahedrons for a more stabile sensing surface. Futhermore, utilizing EBL, studies looking deeper into the fundamental coupling interactions in both one and two dimensional arrays were performed. All of these studies will allow for the logical design of novel plasmonic devices for an array of applications.

  8. Microscopic examination of fingermark residues: Opportunities for fundamental studies.

    PubMed

    Moret, Sébastien; Spindler, Xanthe; Lennard, Chris; Roux, Claude

    2015-10-01

    Despite significant ongoing research, a substantial proportion of latent fingermarks remain undetected in casework. Therefore, to improve existing detection techniques and to allow the development of new approaches, it is important to gain a better understanding of detection mechanisms rather than solely focusing on method formulations. As a starting point, it is crucial to gain a deeper understanding of the fingermark residue itself. Even if the chemical composition is reasonably well understood, little research has been reported on the physical aspects related to the deposition of fingermarks and their interactions with the environment and underlying substrates. This study aimed at exploring various techniques that can be used for the non-destructive visualisation of fingermarks before applying detection techniques. Both light and electron microscopy were investigated. Phase contrast imaging and environmental scanning electron microscopy, coupled with energy-dispersive X-ray spectrometry, proved to be essential tools for the study of latent fingermark deposits. These methods can be used to gather fundamental information that will add to our body of knowledge in this field.

  9. Fundamental Studies of Fluid Mechanics: Stability in Porous Media

    SciTech Connect

    George M. Homsy

    2005-04-28

    This work has been concerned with theoretical, computational and experimental studies of a variety of flow and transport problems that are of generic interest and applicability in energy-related and energy-intensive processes. These include the following. (1) Problems associated with oil recovery: the global economy continues to be dependent on the stable and predictable supply of oil and fossil fuels. This will remain the case for the near term, as current estimates are that world production of oil will peak between 2025 and 2100, depending on assumptions regarding growth. Most of these resources reside in porous rocks and other naturally occurring media. Studies of flow-induced instabilities are relevant to the areas of secondary and enhanced oil recovery. (2) Small scale and Stokes flows: flows in microgeometries and involving interfaces and surfactants are of interest in a myriad of energy-related contexts. These include: pore-level modeling of the fundamental processes by which oil held in porous materials is mobilized and produced; heating and cooling energy cycles involving significant expenditure of energy in conditioning of human environments, heat pipes, and compact heat exchangers; and energy efficiency in large scale separation processes such as distillation and absorption-processes that underlie the chemical process industries. (3) Coating flows: these are of interest in information technologies, including the manufacture of integrated circuits and data storage and retrieval devices. It is estimated that 50-70% of the starting raw materials and intermediate devices in information technology processes must be discarded as a result of imperfections and failure to meet specifications. These in turn are often the result of the inability to control fluid-mechanical processes and flow instabilities. Our work over the grant period is primarily fundamental in nature. We are interested in establishing general principles and behaviors that relate to a variety of

  10. Program for studying fundamental interactions at the PIK reactor facilities

    NASA Astrophysics Data System (ADS)

    Serebrov, A. P.; Vassiljev, A. V.; Varlamov, V. E.; Geltenbort, P.; Gridnev, K. A.; Dmitriev, S. P.; Dovator, N. A.; Egorov, A. I.; Ezhov, V. F.; Zherebtsov, O. M.; Zinoviev, V. G.; Ivochkin, V. G.; Ivanov, S. N.; Ivanov, S. A.; Kolomensky, E. A.; Konoplev, K. A.; Krasnoschekova, I. A.; Lasakov, M. S.; Lyamkin, V. A.; Martemyanov, V. P.; Murashkin, A. N.; Neustroev, P. V.; Onegin, M. S.; Petelin, A. L.; Pirozhkov, A. N.; Polyushkin, A. O.; Prudnikov, D. V.; Ryabov, V. L.; Samoylov, R. M.; Sbitnev, S. V.; Fomin, A. K.; Fomichev, A. V.; Zimmer, O.; Cherniy, A. V.; Shoka, I. V.

    2016-05-01

    A research program aimed at studying fundamental interactions by means of ultracold and polarized cold neutrons at the GEK-4-4' channel of the PIK reactor is presented. The apparatus to be used includes a source of cold neutrons in the heavy-water reflector of the reactor, a source of ultracold neutrons based on superfluid helium and installed in a cold-neutron beam extracted from the GEK-4 channel, and a number of experimental facilities in neutron beams. An experiment devoted to searches for the neutron electric dipole moment and an experiment aimed at a measurement the neutron lifetime with the aid of a large gravitational trap are planned to be performed in a beam of ultracold neutrons. An experiment devoted to measuring neutron-decay asymmetries with the aid of a superconducting solenoid is planned in a beam of cold polarized neutrons from the GEK-4' channel. The second ultracold-neutron source and an experiment aimed at measuring the neutron lifetime with the aid of a magnetic trap are planned in the neutron-guide system of the GEK-3 channel. In the realms of neutrino physics, an experiment intended for sterile-neutrino searches is designed. The state of affairs around the preparation of the experimental equipment for this program is discussed.

  11. Fundamental study of contact resistance behavior in RSW aluminum

    NASA Astrophysics Data System (ADS)

    Sun, Ta-Chien

    2003-06-01

    This dissertation study has developed a fundamental understanding of the contact resistance behavior using the virtual contact volume concept and the equivalent contact resistivity definition. In this research, an integrated experimental-numerical approach was used to demonstrate the proposed equivalent contact resistivity versus temperature relationship. Such relationship was further used to study the expulsion behavior of the resistance spot welding aluminum alloy. A concept of using the constriction ring was demonstrated to be effective in preventing weld expulsion in resistance spot aluminum welds. The a-spot model simulated a single ball contact to define the equivalent contact resistivity. For a specific loading range, the generic equivalent contact resistivity versus temperature relationship, consisting of a proportional term and a exponential term, was derived. The proportionality term represents the increasing contact resistivity with temperature reflecting the Wiedemann-Franz-Lorentz behavior. The exponential term represents the softening effect of the contact surface as temperature increases. With the generic equivalent contact resistivity versus temperature relationship established, an a-spot welding which incorporated the contact pairs with the resistivity relationship leaving three factors as parametric variables and an experimental a-spot welding model were conducted. Both the numerical and experimental analyses show the same relationship that is defined by the theoretical hypothesis of a-spot model. The parametric study was conducted to quantify the parametric factors based on comparisons on nugget size and electrical potential drops across the electrodes. For an ideal combination of parameters at the Cu/Al interface and the Al/Al faying surface, both the comparisons of weld nugget size and potential drops are satisfactory. The mechanical analysis proposed a concept that expulsion would occur when the crack tip is within the solidus nugget zone at

  12. Fundamental studies on welding-induced distortion in thin plates

    NASA Astrophysics Data System (ADS)

    Han, Myoung Soo

    2002-09-01

    Welding of thin plates can cause extensive angular and buckling distortions that deteriorate structural integrity and production reliability. Remarkable developments in computer technology in recent years have improved numerical prediction capability of welding distortion. Despite of many uncertainties in the distortion mechanism, it is generally agreed that welding distortion is predictable if one can approximate the inherent strains distributed in and around the weld region. In this dissertation, a fundamental study on the prediction and the control of welding-induced distortion in thin plates was conducted through correlating inherent strains with welding process variables and the degree of constraints. Experimental studies were also performed to verify the numerical procedure for welding distortion analyses. Significant findings observed through the study are summarized as follows: (1) The peak temperatures and the nil-plasticity peak temperature uniquely determined magnitudes of longitudinal inherent strains. (2) The effective inherent strain responsible for angular distortion was produced under non-uniform temperature distribution through the thickness, and estimated by adding halves of longitudinal plastic strains to transverse inherent strains. (3) The shrinkage volume model considering effective inherent strains reasonably predicted magnitudes of angular distortion. (4) The onset of longitudinal distortion was strongly influenced by transient temperature fields. The more intensified thermal field was required for the onset in the smaller plate subjected to the smaller heat input. Longitudinal distortion in small plates grew for a limited cooling period, and it in large plates continued to grow until the completion of the cooling cycle. (5) The critical curve from eigenvalue analyses showed that the buckling instability is manifested as plate size or heat input increases. Buckling instability predicted by eigenvalue analyses is closely related to the

  13. Fundamental Studies of Crystal Growth of Microporous Materials

    NASA Technical Reports Server (NTRS)

    Dutta, P.; George, M.; Ramachandran, N.; Schoeman, B.; Curreri, Peter A. (Technical Monitor)

    2002-01-01

    Microporous materials are framework structures with well-defined porosity, often of molecular dimensions. Zeolites contain aluminum and silicon atoms in their framework and are the most extensively studied amongst all microporous materials. Framework structures with P, Ga, Fe, Co, Zn, B, Ti and a host of other elements have also been made. Typical synthesis of microporous materials involve mixing the framework elements (or compounds, thereof) in a basic solution, followed by aging in some cases and then heating at elevated temperatures. This process is termed hydrothermal synthesis, and involves complex chemical and physical changes. Because of a limited understanding of this process, most synthesis advancements happen by a trial and error approach. There is considerable interest in understanding the synthesis process at a molecular level with the expectation that eventually new framework structures will be built by design. The basic issues in the microporous materials crystallization process include: (1) Nature of the molecular units responsible for the crystal nuclei formation; (2) Nature of the nuclei and nucleation process; (3) Growth process of the nuclei into crystal; (4) Morphological control and size of the resulting crystal; (5) Surface structure of the resulting crystals; (6) Transformation of frameworks into other frameworks or condensed structures. The NASA-funded research described in this report focuses to varying degrees on all of the above issues and has been described in several publications. Following is the presentation of the highlights of our current research program. The report is divided into five sections: (1) Fundamental aspects of the crystal growth process; (2) Morphological and Surface properties of crystals; (3) Crystal dissolution and transformations; (4) Modeling of Crystal Growth; (5) Relevant Microgravity Experiments.

  14. Fundamental studies of superconductors using scanning magnetic imaging

    NASA Astrophysics Data System (ADS)

    Kirtley, J. R.

    2010-12-01

    In this review I discuss the application of scanning magnetic imaging to fundamental studies of superconductors, concentrating on three scanning magnetic microscopies—scanning SQUID microscopy (SSM), scanning Hall bar microscopy (SHM) and magnetic force microscopy (MFM). I briefly discuss the history, sensitivity, spatial resolution, invasiveness and potential future developments of each technique. I then discuss a selection of applications of these microscopies. I start with static imaging of magnetic flux: an SSM study provides deeper understanding of vortex trapping in narrow strips, which are used to reduce noise in superconducting circuitry. Studies of vortex trapping in wire lattices, clusters and arrays of rings and nanoholes show fascinating ordering effects. The cuprate high-Tc superconductors are shown to have predominantly d-wave pairing symmetry by magnetic imaging of the half-integer flux quantum effect. Arrays of superconducting rings act as a physical analog for the Ising spin model, with the half-integer flux quantum effect helping to eliminate one source of disorder in antiferromagnetic arrangements of the ring moments. Tests of the interlayer tunneling model show that the condensation energy available from this mechanism cannot account for the high critical temperatures observed in the cuprates. The strong divergence in the magnetic fields of Pearl vortices allows them to be imaged using SSM, even for penetration depths of a millimeter. Unusual vortex arrangements occur in samples comparable in size to the coherence length. Spontaneous magnetization is not observed in Sr2RuO4, which is believed to have px ± ipy pairing symmetry, although effects hundreds of times bigger than the sensitivity limits had been predicted. However, unusual flux trapping is observed in this superconductor. Finally, unusual flux arrangements are also observed in magnetic superconductors. I then turn to vortex dynamics: imaging of vortices in rings of highly underdoped

  15. Fundamentals of Physics, Student Study Guide, Extended 7th Edition

    NASA Astrophysics Data System (ADS)

    Halliday, David; Resnick, Robert; Walker, Jearl

    2004-06-01

    No other book on the market today can match the 30-year success of Halliday, Resnick and Walker's Fundamentals of Physics! Fundamentals of Physics, 7th Edition and the Extended Version, 7th Edition offer a solid understanding of fundamental physics concepts, helping readers apply this conceptual understanding to quantitative problem solving, in a breezy, easy-to-understand style. A unique combination of authoritative content and stimulating applications. * Numerous improvements in the text, based on feedback from the many users of the sixth edition (both instructors and students) * Several thousand end-of-chapter problems have been rewritten to streamline both the presentations and answers * 'Chapter Puzzlers' open each chapter with an intriguing application or question that is explained or answered in the chapter * Problem-solving tactics are provided to help beginning Physics students solve problems and avoid common error * The first section in every chapter introduces the subject of the chapter by asking and answering, "What is Physics?" as the question pertains to the chapter * Numerous supplements available to aid teachers and students The extended edition provides coverage of developments in Physics in the last 100 years, including: Einstein and Relativity, Bohr and others and Quantum Theory, and the more recent theoretical developments like String Theory.

  16. Fundamental Studies of Hydroporphyrin Architectures for Solar-Energy Applications

    SciTech Connect

    Lindsey, Jonathan S.; Bocian, David F.; Holten, Dewey; Kirmaier, Christine

    2013-10-30

    /electron transfer between (hydro)porphyrins as a function of array size, distance between components, linker type, site of linker connection, and frontier molecular orbital composition. (iv) Build upon the results of the aforementioned studies to design, synthesize, and characterize integrated architectures that incorporate a panchromatic absorber and other molecular components that that afford efficient hole/electron migration and long-lived charge separation. Such architectures will be examined on solid substrates to explore the viability of the component parts and processes under application-oriented conditions. Such architectures or successors may prove directly useful for solar-energy conversion systems. An equally important attribute is to serve as a test-bed for successful integration of the requisite properties and processes, some of which require rather weak coupling between constituents, some of which require very strong electronic interactions to elicit the desired behavior, and all of which should be tunable under molecular design control to the extent possible. Collectively, the proposed studies will provide fundamental insights into molecular properties, interactions, and processes relevant to the design of molecular architectures for solar-energy conversion. The accomplishment of these goals is only possible through a highly synergistic program that encompasses molecular design, synthesis, and in-depth characterization.

  17. Fundamental studies of passivity and passivity breakdown. Final report

    SciTech Connect

    Macdonald, D.D.; Urquidi-Macdonald, M.; Song, H.; Biaggio-Rocha, S.; Searson, P.

    1991-11-01

    This report summarizes the findings of our fundamental research program on passivity and passivity breakdown. During the past three and one half years in this program (including the three year incrementally-funded grant prior to the present grant), we developed and experimentally tested various physical models for the growth and breakdown of passive films on metal surfaces. These models belong to a general class termed ``point defects models`` (PDMs), in which the growth and breakdown of passive films are described in terms of the movement of anion and cation vacancies.

  18. Microfluidic platforms and fundamental electrocatalysis studies for fuel cell applications

    NASA Astrophysics Data System (ADS)

    Cohen, Jamie Lee

    The fabrication and testing of a planar membraneless microchannel fuel cell, based on a silicon microchannel, is described in detail. Laminar flow of fuel and oxidant streams, one on top of the other, prevents fuel crossover while allowing ionic transport at the interface between the two solutions. By employing laminar flow, the useful functions of a membrane are retained, while bypassing its inherent limitations. The planar design maximizes the anode and cathode areas, and elimination of the membrane affords broad flexibility in the choice of fuel and oxidant. Fuels including formic acid, methanol, ethanol, sodium borohydride and hydrogen were tested along with oxidants such as oxygen, hydrogen peroxide and potassium permanganate. Steps taken to improve voltage, current density, and overall power output have been addressed, including the testing of a dual electrolyte system and the use of micro-patterned electrode surfaces to enhance fuel utilization. As the complexity of the fuels studied in the microchannel fuel cell increased, it was imperative to characterize these fuels using electrochemical techniques prior to utilization in the fuel cell. The oxidation pathway of the liquid fuel methanol was studied rigorously because of its importance for micro-fuel cell applications. Activation energies for methanol oxidation at a Ptpoly surface were determined using electrochemical techniques, providing a benchmark for the comparison of activation energies of other Pt-based electrocatalysts for methanol oxidation at a given potential. A protocol to obtain Ea values was established in three different electrolytes and experimental parameters that influence the magnitude of these values are discussed in detail. The oxidation pathways of sodium borohydride were also examined at Au, Pt, and Pd surfaces using cyclic voltammetry, chronoamperometry, and rotating disk electrode voltammetry. In addition to studies on bulk Ptpoly surfaces, new bulk intermetallic catalysts were

  19. Additives

    NASA Technical Reports Server (NTRS)

    Smalheer, C. V.

    1973-01-01

    The chemistry of lubricant additives is discussed to show what the additives are chemically and what functions they perform in the lubrication of various kinds of equipment. Current theories regarding the mode of action of lubricant additives are presented. The additive groups discussed include the following: (1) detergents and dispersants, (2) corrosion inhibitors, (3) antioxidants, (4) viscosity index improvers, (5) pour point depressants, and (6) antifouling agents.

  20. Fundamental studies of fluid mechanics and stability in porous media

    SciTech Connect

    Homsy, G.M.

    1992-07-01

    We have been active in four areas: Numerical and analytical studies of viscous fingering in miscible displacements, including non- monotonic mobility profiles; numerical and analytical studies of the effect of non-Newtonian fluid characteristics on instabilities; experimental studies of instabilities of moving contact lines for Newtonian and non-Newtonian fluids; and studies of natural convective energy transport due to time-dependent body forces.

  1. Fundamental studies of tin whiskering in microelectronics finishes

    NASA Astrophysics Data System (ADS)

    Pinol, Lesly Agnes

    Common electronics materials, such as tin, copper, steel, and brass, are ambient reactive under common use conditions, and as such are prone to corrosion. During the early 1940s, reports of failures due to electrical shorting of components caused by 'whisker' (i.e., filamentary surface protrusion) growth on many surface types---including the aforementioned metals---began to emerge. Lead alloying of tin (3--10% by weight, typically in the eutectic proportion) eliminated whiskering risk for decades, until the July 2006 adoption of the Restriction of Hazardous Substances (RoHS) directive was issued by the European Union. This directive, which has since been adopted by California and parts of China, severely restricted the use of lead (<1000 ppm) in all electrical and electronics equipment being placed on the EU market, imposing the need for developing reliable new "lead-free" alternatives to SnPb. In spite of the abundance of modern-day anecdotes chronicling whisker-related failures in satellites, nuclear power stations, missiles, pacemakers, and spacecraft navigation equipment, pure tin finishes are still increasingly being employed today, and the root cause(s) of tin whiskering remains elusive. This work describes a series of structured experiments exploring the fundamental relationships between the incidence of tin whiskering (as dependent variable) and numerous independent variables. These variables included deposition method (electroplating, electroless plating, template-based electrochemical synthesis, and various physical vapor deposition techniques, including resistive evaporation, electron beam evaporation, and sputtering), the inclusion of microparticles and organic contamination, the effects of sample geometry, and nanostructuring. Key findings pertain to correlations between sample geometry and whisker propensity, and also to the stress evolution across a series of 4"-diameter silicon wafers of varying thicknesses with respect to the degree of post

  2. Fundamental studies on the metal chloride cathodes in sodium batteries

    NASA Technical Reports Server (NTRS)

    Ratnakumar, B. V.; Attia, A.; Halpert, G.

    1990-01-01

    The authors report studies of the passivation of the NiCl2 electrode during reduction, its effect on the electrochemical rate kinetics for the reduction, and its dependence on the state of charge of the electrode. NiCl2 exhibits passive behavior more readily at lower states of charge due to a decrease in the electrochemical area, resulting from NaCl deposited during reduction. The passive behavior is evident from the DC polarization curves as well as AC impedance plots at the same potentials, implying a correlation between them. The results of the studies are presented in detail.

  3. Additional EIPC Study Analysis. Final Report

    SciTech Connect

    Hadley, Stanton W; Gotham, Douglas J.; Luciani, Ralph L.

    2014-12-01

    Between 2010 and 2012 the Eastern Interconnection Planning Collaborative (EIPC) conducted a major long-term resource and transmission study of the Eastern Interconnection (EI). With guidance from a Stakeholder Steering Committee (SSC) that included representatives from the Eastern Interconnection States Planning Council (EISPC) among others, the project was conducted in two phases. Phase 1 involved a long-term capacity expansion analysis that involved creation of eight major futures plus 72 sensitivities. Three scenarios were selected for more extensive transmission- focused evaluation in Phase 2. Five power flow analyses, nine production cost model runs (including six sensitivities), and three capital cost estimations were developed during this second phase. The results from Phase 1 and 2 provided a wealth of data that could be examined further to address energy-related questions. A list of 14 topics was developed for further analysis. This paper brings together the earlier interim reports of the first 13 topics plus one additional topic into a single final report.

  4. Sexual Fundamentalism and Performances of Masculinity: An Ethnographic Scene Study

    ERIC Educational Resources Information Center

    Gallagher, Kathleen

    2006-01-01

    The study on which this paper is based examined the experiences of students in order to develop a theoretical and empirically grounded account of the dynamic social forces of inclusion and exclusion experienced by youth in their unique contexts of North American urban schooling. The ethnographic scenes, organized into four "beats," theatrically…

  5. Fundamental spectroscopic studies of carbenes and hydrocarbon radicals

    SciTech Connect

    1999-03-12

    Determination of bond dissociation energies and heats of formation of hydrocarbon radicals and carbenes requires knowledge of their structures, but this is not provided by standard mass spectrometric studies; what is needed is high-resolution spectroscopy, often best achieved at centimeter and millimeter wavelengths. Nearly 60 reactive organic molecules were investigated in the period from 1988--1998.

  6. A study of the fundamental characteristics of 2175A extinction

    NASA Technical Reports Server (NTRS)

    Cardelli, Jason A.; Savage, Blair D.

    1987-01-01

    The characteristics of interstellar extinction were studied in the region of the 2175 A feature for lines of sight which appear to exhibit unusually weak ultraviolet extinction. The analysis was based upon a parameterization of the observed extinction via fitting specific mathematical functions in order to determine the position and width of the 2175 A feature. The data are currently being analyzed.

  7. Fundamental spectroscopic studies of carbenes and hydrocarbon radicals

    SciTech Connect

    Gottlieb, C.A.; Thaddeus, P.

    1993-12-01

    Highly reactive carbenes and carbon-chain radicals are studied at millimeter wavelengths by observing their rotational spectra. The purpose is to provide definitive spectroscopic identification, accurate spectroscopic constants in the lowest vibrational states, and reliable structures of the key intermediates in reactions leading to aromatic hydrocarbons and soot particles in combustion.

  8. Plasma Assisted Combustion: Fundamental Studies and Engine Applications

    NASA Astrophysics Data System (ADS)

    Lefkowitz, Joseph K.

    Successful and efficient ignition in short residence time environments or ultra-lean mixtures is a key technological challenge for the evolution of advanced combustion devices in terms of both performance and efficiency. To meet this challenge, interest in plasma assisted combustion (PAC) has expanded over the past 20 years. However, understanding of the underlying physical processes of ignition by plasma discharge remains elementary. In order to shed light on the key processes involved, two main thrusts of research were undertaken in this dissertation. First, demonstration of the applicability of plasma discharges in engines and engine-like environments was carried out using a microwave discharge and a nanosecond repetitively pulsed discharge in an internal combustion engine and a pulsed detonation engine, respectively. Major conclusions include the extension of lean ignition limits for both engines, significant reduction of ignition time for mixtures with large minimum ignition energy, and the discovery of the inter-pulse coupling effect of nanosecond repetitively pulsed (NRP) discharges at high frequency. In order to understand the kinetic processes that led to these improvements, the second thrust of research directly explored the chemical kinetic processes of plasma discharges with hydrocarbon fuels. For this purpose, a low pressure flow reactor with a NRP dielectric barrier discharge cell was assembled. The discharge cell was fitted with a Herriott type multipass mirror arrangement, which allowed quantitative laser absorption spectroscopy to be performed in situ during the plasma discharge. Experiments on methane and ethylene mixtures with oxygen, argon, and helium revealed the importance of low temperature oxidation pathways in PAC. In particular, oxygen addition reactions were shown to be of primary importance in the oxidation of these small hydrocarbons in the temperature range of 300-600 K. Kinetic modeling tools, including both a coupled plasma and

  9. Fundamental Studies of Fluid Mechanics: Stability in Porous Media

    SciTech Connect

    Homsy, George M.

    2014-02-12

    We summarize our research results in three main areas: coating flows; electrohydrodynamics of drops; and wetting and spreading of drops. Experimental, computational and analytical methods are used to address a variety of issues. Coating flow studies include the effect of roughness, surfactants, and adsorbed particles on the dynamics of dip-coating. Electrohydrodynamic studies include drop deformation in uniform electric fields, shape distortion due to charge convection in sedimenting drops, and driving chaotic advection by either an electric field inclined to the direction of drop motion or time-periodic changes in the direction of the electric field. Heat and mass transport from chaotically mixed droplets exhibit unexpected and remarkable increases in the rates of transport. Finally, we develop an analytical solution to the problem of a static droplet, and use numerical techniques to predict its migration due to surface tension gradients.

  10. Fundamental Approaches to the Study of Zebrafish Nutrition

    PubMed Central

    Watts, Stephen A.; Powell, Mickie; D’Abramo, Louis R.

    2014-01-01

    The value of the zebrafish model has been well established. However, culture variability within and among laboratories remains a concern, particularly as it relates to nutrition. Investigators using rodent models addressed this concern several decades ago and have developed strict nutritional regimes to which their models adhere. These investigators decreased the variability associated with nutrition in most studies by developing standardized reference and open formulation diets. Zebrafish investigators have not embraced this approach. In this article, we address the problems associated with the lack of nutritional information and standardization in the zebrafish research community. Based on the knowledge gained from studies of other animals, including traditional research models, other fish species, domesticated and companion animals, and humans, we have proposed an approach that seeks to standardize nutrition research in zebrafish. We have identified a number of factors for consideration in zebrafish nutrition studies and have suggested a number of proposed outcomes. The long term-goal of nutrition research will be to identify the daily nutritional requirements of the zebrafish and to develop appropriate standardized reference and open formulation diets. PMID:23382346

  11. Overview of fundamental study of pazopanib in cancer.

    PubMed

    Zhao, Hong-Lin; Yang, Fan; Huang, Xin; Zhou, Qing-Hua

    2014-11-01

    Angiogenesis is an indispensible process for tumor growth and metastasis. Anti-angiogenesis based therapy is one of the most promising treatments for inhibiting cancer progression. Through the exploration of inhibitors of vascular endothelial growth factor receptor (VEGFR)-2, deemed as the major angiogenesis pathway, pazopanib was found as a small molecular pan-VEGFR and pan-platelet-derived growth factor receptor (PDGFR) inhibitor, with suitable pharmacodynamic and pharmacokinetic parameters to be an oral drug. In an vitro study, pazopanib exerted anti-tumor effect through mechanisms including the Raf-MAPK/ERK (MEK)-extracellular signal-regulated kinase (ERK) pathway, and directly targeted on v-raf murine sarcoma viral oncogene homolog B (B-raf) as well. It inhibited the proliferation of cell lines, such as DU-145 and HRC-45 in hepatocellular carcinoma, through mechanisms like "cell cycle arrest." In vivo xenograft studies and phase I/II clinical trials revealed a series of plasma cytokine and angiogenic factors, such as interleukin (IL)-6, IL-12, hepatocyte growth factor (HGF), and soluble VEGFR2, which have significant association with clinical curative effect. Pazopanib has been shown to be effective in solid tumors and some hematological malignancies. Future studies should focus on the exploration of biomarkers to screen sensitive patients and concomitant or metronomic dosage with other kinds of medicines.

  12. Overview of fundamental study of pazopanib in cancer

    PubMed Central

    Zhao, Hong-Lin; Yang, Fan; Huang, Xin; Zhou, Qing-Hua

    2014-01-01

    Angiogenesis is an indispensible process for tumor growth and metastasis. Anti-angiogenesis based therapy is one of the most promising treatments for inhibiting cancer progression. Through the exploration of inhibitors of vascular endothelial growth factor receptor (VEGFR)-2, deemed as the major angiogenesis pathway, pazopanib was found as a small molecular pan-VEGFR and pan-platelet-derived growth factor receptor (PDGFR) inhibitor, with suitable pharmacodynamic and pharmacokinetic parameters to be an oral drug. In an vitro study, pazopanib exerted anti-tumor effect through mechanisms including the Raf-MAPK/ERK (MEK)-extracellular signal-regulated kinase (ERK) pathway, and directly targeted on v-raf murine sarcoma viral oncogene homolog B (B-raf) as well. It inhibited the proliferation of cell lines, such as DU-145 and HRC-45 in hepatocellular carcinoma, through mechanisms like “cell cycle arrest.” In vivo xenograft studies and phase I/II clinical trials revealed a series of plasma cytokine and angiogenic factors, such as interleukin (IL)-6, IL-12, hepatocyte growth factor (HGF), and soluble VEGFR2, which have significant association with clinical curative effect. Pazopanib has been shown to be effective in solid tumors and some hematological malignancies. Future studies should focus on the exploration of biomarkers to screen sensitive patients and concomitant or metronomic dosage with other kinds of medicines. PMID:26767042

  13. Fundamental studies of reactive intermediates in homogeneous catalysis

    SciTech Connect

    Not Available

    1993-10-01

    The studies involve dissociation of Fe(CO){sub n}{sup {minus}}, Ni(CO){sub n}{sub {minus}}, and other carbonyl anions; decarboxylation of (CO){sub 4}FeCOOH{sup {minus}} to form CO{sub 2} and (CO){sub 4}FeH{sup {minus}} in the water gas shift reaction; gas-phase bimolecular reactions of carbonyl anions and O{sub 2}; reaction of O{sub 2} with CpMn(CO){sub 2}{sup {minus}}; gas-phase chemistry of fullerene anions; and gas-phase thermochemistry of bicarbonate ion, bisulfite ion, and their conjugate acids (sulfonate ion was produced).

  14. Fundamental study of phosphor separation by controlling magnetic force

    NASA Astrophysics Data System (ADS)

    Wada, Kohei; Mishima, Fumihito; Akiyama, Yoko; Nishijima, Shigehiro

    2013-11-01

    The phosphor wastes consist of phosphors with different emission colors, green (LAP), red (YOX), blue (BAM) and white (HP). It is required to recover and reuse the rare earth phosphors with high market value. In this study, we tried to separate the phosphor using the magnetic separation by HTS bulk magnet utilizing the differences of magnetic susceptibility by the type of phosphors. We succeeded in the successive separation of HP with low market value from YOX and BAM including the rare earth using the magnetic Archimedes method. In this method, vertical and radial components of the magnetic force were used.

  15. Fundamentals of Mold Free Casting: Experimental and Computational Studies

    NASA Technical Reports Server (NTRS)

    Tryggvason, Gretar; Ceccio, Steven

    1997-01-01

    Researchers are developing the technology of 'Ballistic Particle Manufacturing' (BPM) in which individual drops are precisely layered onto a substrate, and the drops are deposited so as to prevent splatting. These individual drops will ultimately be combined to form a net-shape, three-dimensional object. Our understanding of controlled drop deposition as applied to BPM is far from complete. Process parameters include the size and temperature of the liquid metal drop, its impact velocity and trajectory, and the condition and temperature of the substrate. Quantitative knowledge of the fluid mechanics and heat transfer of drop deposition and solidification are necessary to fully optimize the manufacturing process and to control the material microstructure of the final part. The object of this study is to examine the dynamics of liquid metal drops as they impinge upon a solid surface and solidify under conditions consistent with BPM (i.e. conditions which produce non-splatting drops). A program of both numerical simulations and experiments will be conducted. Questions this study will address include the following: How do the deformation and solidification of the drop depend on the properties of the fluid drop and the solid substrate? How does the presence of previously deposited drops affect the impingement and solidification process? How does the impingement of the new drop affect already deposited material? How does the cooling rate and solidification of the drops influence the material microstructure?

  16. Fundamental study on magnetic separation of organic dyes in wastewater

    NASA Astrophysics Data System (ADS)

    Fang, M.; Mishima, F.; Akiyama, Y.; Nishijima, S.

    2010-11-01

    The objective of this study is to separate dyes in wastewater with high efficiency and speed using High Gradient Magnetic Separation with superconducting magnet. Two main technologies are necessary for magnetic separation; one is magnetic seeding technology to provide ferromagnetism to the substance, and the other is magnetic separation technology using superconducting magnet and magnetic filters. In order to separate organic dyes, it is necessary to clarify the mechanism of magnetic seeding, and to design a suitable magnetic seeding method depending on the kind of object dye. Six kinds of dyes which are widely used in industry were adopted to investigate the possibility of the magnetic seeding and interaction mechanism between dye and ferromagnetic particles. As a result, it was shown that electrostatic interaction is one of the main interactions between organic dye and ferromagnetic particles.

  17. Fundamental studies of the solid-particle erosion of silicon

    NASA Technical Reports Server (NTRS)

    Routbort, J. L.; Scattergood, R. O.

    1982-01-01

    The predictions of the theories of solid-particle erosion of brittle materials are compared to experimental results of studies in which angular Al2O3 particles with mean diameters D of 23 to 270 microns are used to erode (111) surfaces of silicon single crystals at impact angles alpha from 20 to 90 deg and velocities v from 30 to 150 m/s. The description of the steady state erosion rate by a power law, delta W varies directly as (v sin alpha)(n)D(m) must be modified to include threshold and plasticity effects. Furthermore the velocity exponent n depends on D. Results using abrasives of different sizes mixed together can be explained using a logarithmic-normal distribution. The results of transient experiments can be used to explain the synergistic effects which are observed using a biomodal distribution of abrasives.

  18. Studies of the fundamentals of solids state batteries

    NASA Astrophysics Data System (ADS)

    Abraham, K. M.; Alamgir, M.

    1990-11-01

    Several methods have been developed to dimensionally stabilize polymer electrolytes based on poly-(bis (methoxy ethoxy ethoxide) phosphazene), known as MEEP. In contrast to the poor dimensional stability exhibited by complexes of MEEP with most Li salts, those prepared with LiAlCl4 have been isolated as the first example of free-standing MEEP-(LiX)n films. The mechanical properties of dimensionally unstable MEEP-(LIX)n complexes can be significantly improved by forming composites with polymers such as poly(ethylene oxide), poly(propylene oxide), poly(ethylene glycol diacrylate) and poly(vinyl pyrrolidinone). The conductivity of 6.7 x 10(exp -5) ohm(exp -1) cm(exp -1) at 25 C exhibited by 55 w/o MEEP/45 w/o PEO-(LiN(CF3SO2)2)0.13 is among the highest values reported to date for a dimensionally stable electrolyte. The preparation, and conductivity, calorimetric and electrochemical studies of these electrolytes are described. Cyclic voltammetric data indicated that these electrolytes have anodic stability at least up to 4.5V versus Li(+)/Li. They have shown excellent compatibility with Li metal making them suitable for use as Li(+) conductive solid electrolytes in solid-state Li batteries. Li/TiS2 solid-state cells utilizing some of these electrolytes have exceeded 200 cycles.

  19. Fundamental Studies of Droplet Combustion at Reduced Gravity

    NASA Technical Reports Server (NTRS)

    Williams, F. A.

    1985-01-01

    Reduced gravity is used to carry out scientific investigations of droplet combustion. In earlier work a preliminary conceptual design had been developed for droplet burning experiments for Spacelab. Refinements of the earlier work with special consideration given to possible experiments for Mid-Deck Modules of the Space Shuttle is discussed. A re-evaluation of suitable experiments on droplet combustion is done to ascertain whether influences of reduced buoyancy on time-dependent processes of heat and mass transfer in the gas or in the liquid on extinction processes or on disruptive burning phenomena are best suited for further investigation. Components of the experimental apparatus, which include a droplet dispensing system, a droplet positioning system, a droplet ignition system and provision for recording, primarily photographically, the combustion of the individual droplet in a chamber having a controlled gas atmosphere, are studied to determine optimal approaches to the experimental design. Methods for data reduction and interpretation are being made more specific, particularly in the context of an objective to calculate overall gas-phase chemical-kinetic parameters for the combustion from observations of extinction conditions in different atmospheres.

  20. Fundamental Studies of Crystal Growth of Microporous Materials

    NASA Technical Reports Server (NTRS)

    Singh, Ramsharan; Doolittle, John, Jr.; Payra, Pramatha; Dutta, Prabir K.; George, Michael A.; Ramachandran, Narayanan; Schoeman, Brian J.

    2003-01-01

    Microporous materials are framework structures with well-defined porosity, often of molecular dimensions. Zeolites contain aluminum and silicon atoms in their framework and are the most extensively studied amongst all microporous materials. Framework structures with P, Ga, Fe, Co, Zn, B, Ti and a host of other elements have also been made. Typical synthesis of microporous materials involve mixing the framework elements (or compounds, thereof) in a basic solution, followed by aging in some cases and then heating at elevated temperatures. This process is termed hydrothermal synthesis, and involves complex chemical and physical changes. Because of a limited understanding of this process, most synthesis advancements happen by a trial and error approach. There is considerable interest in understanding the synthesis process at a molecular level with the expectation that eventually new framework structures will be built by design. The basic issues in the microporous materials crystallization process include: (a) Nature of the molecular units responsible for the crystal nuclei formation; (b) Nature of the nuclei and nucleation process; (c) Growth process of the nuclei into crystal; (d) Morphological control and size of the resulting crystal; (e) Surface structure of the resulting crystals; and (f) Transformation of frameworks into other frameworks or condensed structures.

  1. A fundamental study of nucleate pool boiling under microgravity

    NASA Technical Reports Server (NTRS)

    Ervin, Jamie S.; Merte, Herman, Jr.

    1991-01-01

    An experimental study of incipient boiling in short-term microgravity and with a/g = +/- 1 for pool boiling was performed. Calibrated thin gold films sputtered on a smoothly polished quartz surface were used simultaneously for thermal resistance measurements and heating of the boiling surface. The gold films were used for both transient and quasi-steady heating surface temperature measurements. Two test vessels were constructed for precise measurement and control of fluid temperature and pressure: a laboratory pool boiling vessel for the a/g = +/- experiments and a pool boiling vessel designed for the 131 m free-fall in the NASA Lewis Research Center Microgravity Research Facility for the microgravity tests. Measurements included the heater surface temperature, the pressure near the heating surface, and the bulk liquid temperatures. High speed photography was used in the experiments. With high quality microgravity and the measured initial temperature of the quiescent test fluid, R113, the temperature distribution in the liquid at the moment of boiling inception resulting from an imposed step in heat flux is known with a certainty not possible previously. The types of boiling propagation across the large flat heating surface are categorized; the conditions necessary for their occurrence are described. Explosive boiling propagation with a striking pattern of small scale protuberances over the entire vapor mass periphery not observed previously at low heat flux levels is described. For the heater surface with a/g = -1, a step in the heater surface temperature of short duration was imposed. The resulting liquid temperature distribution at the moment of boiling inception was different from that obtained with a step in heat flux.

  2. A Fundamental Study of Nucleate Pool Boiling Under Microgravity

    NASA Technical Reports Server (NTRS)

    Ervin, Jamie S.; Merte, Herman, Jr.

    1996-01-01

    An experimental study of incipient boiling in short-term microgravity and with a/g = +/- 1 for pool boiling was performed. Calibrated thin gold films sputtered on a smoothly polished quartz surface were used simultaneously for thermal-resistance measurements and heating of the boiling surface. The gold films were used for both transient and quasi-steady heating surface temperature measurements. Two test vessels were constructed for precise measurement and control of fluid temperature and pressure: a laboratory pool boiling vessel for the a/g = +/- 1 experiments and a pool boiling vessel designed for the 131 m free-fall in the NASA Lewis Research Center Microgravity Research Facility for the microgravity tests. Measurements included the heater surface temperature, the pressure near the heating surface, the bulk liquid temperatures. High speed photography (up to 1,000 frames per second) was used in the experiments. With high quality microgravity and the measured initial temperature of the quiescent test fluid, R113, the temperature distribution in the liquid at the moment of boiling inception resulting from an imposed step in heat flux is known with a certainty not possible previously. The types of boiling propagation across the large flat heating surface, some observed here for the first time, are categorized; the conditions necessary for their occurrence are described. Explosive boiling propagation with a striking pattern of small scale protuberances over the entire vapor mass periphery not observed previously at low heat flux levels (on the order of 5 W/cm(exp 2)) is described. For the heater surface with a/g = -1, a step in the heater surface temperature of short duration was imposed. The resulting liquid temperature distribution at the moment of boiling inception was different from that obtained with a step in heat flux.

  3. Fundamental Study of Material Flow in Friction Stir Welds

    NASA Technical Reports Server (NTRS)

    Reynolds, Anthony P.

    1999-01-01

    The presented research project consists of two major parts. First, the material flow in solid-state, friction stir, butt-welds as been investigated using a marker insert technique. Changes in material flow due to welding parameter as well as tool geometry variations have been examined for different materials. The method provides a semi-quantitative, three-dimensional view of the material transport in the welded zone. Second, a FSW process model has been developed. The fully coupled model is based on fluid mechanics; the solid-state material transport during welding is treated as a laminar, viscous flow of a non-Newtonian fluid past a rotating circular cylinder. The heat necessary for the material softening is generated by deformation of the material. As a first step, a two-dimensional model, which contains only the pin of the FSW tool, has been created to test the suitability of the modeling approach and to perform parametric studies of the boundary conditions. The material flow visualization experiments agree very well with the predicted flow field. Accordingly, material within the pin diameter is transported only in the rotation direction around the pin. Due to the simplifying assumptions inherent in the 2-D model, other experimental data such as forces on the pin, torque, and weld energy cannot be directly used for validation. However, the 2-D model predicts the same trends as shown in the experiments. The model also predicts a deviation from the "normal" material flow at certain combinations of welding parameters, suggesting a possible mechanism for the occurrence of some typical FSW defects. The next step has been the development of a three-dimensional process model. The simplified FSW tool has been designed as a flat shoulder rotating on the top of the workpiece and a rotating, cylindrical pin, which extends throughout the total height of the flow domain. The thermal boundary conditions at the tool and at the contact area to the backing plate have been varied

  4. Fundamental studies in hypersonic aeroelasticity using computational methods

    NASA Astrophysics Data System (ADS)

    Thuruthimattam, Biju James

    This dissertation describes the aeroelastic analysis of a generic hypersonic vehicle using methods in computational aeroelasticity. This objective is achieved by first considering the behavior of a representative configuration, namely a two degree-of-freedom typical cross-section, followed by that of a three-dimensional model of the generic vehicle, operating at very high Mach numbers. The typical cross-section of a hypersonic vehicle is represented by a double-wedge cross-section, having pitch and plunge degrees of freedom. The flutter boundaries of the typical cross-section are first generated using third-order piston theory, to serve as a basis for comparison with the refined calculations. Prior to the refined calculations, the time-step requirements for the reliable computation of the unsteady airloads using Euler and Navier-Stokes aerodynamics are identified. Computational aeroelastic response results are used to obtain frequency and damping characteristics, and compared with those from piston theory solutions for a variety of flight conditions. A parametric study of offsets, wedge angles; and static angle of attack is conducted. All the solutions are fairly close below the flutter boundary, and differences between the various models increase when the flutter boundary is approached. For this geometry, differences between viscous and inviscid aeroelastic behavior are not substantial. The effects of aerodynamic heating on the aeroelastic behavior of the typical cross-section are incorporated in an approximate manner, by considering the response of a heated wing. Results indicate that aerodynamic heating reduces aeroelastic stability. This analysis was extended to a generic hypersonic vehicle, restrained such that the rigid-body degrees of freedom are absent. The aeroelastic stability boundaries of the canted fin alone were calculated using third-order piston theory. The stability boundaries for the generic vehicle were calculated at different altitudes using

  5. Fundamental Physics with the ASI Lunar Mission MAGIA (Phase A Study)

    NASA Astrophysics Data System (ADS)

    Dell'Agnello, S.; Currie, D.; Delle Monache, G.; Vittori, R.; Bellettini, G.; March, R.; Tauraso, R.; Boni, A.; Cantone, C.; Garattini, M.; Lops, C.; Martini, M.; Prosperi, C.

    2008-07-01

    MAGIA is a mission selected by ASI for Phase A study for the planetology science and fundamental physics measurements: Gravitational Redshift; Precursor test of Proposal LLRRA-21 (NASA LSSO); Measurement of the Selenocenter.

  6. Structure Property Studies for Additively Manufactured Parts

    SciTech Connect

    Milenski, Helen M; Schmalzer, Andrew Michael; Kelly, Daniel

    2015-08-17

    Since the invention of modern Additive Manufacturing (AM) processes engineers and designers have worked hard to capitalize on the unique building capabilities that AM allows. By being able to customize the interior fill of parts it is now possible to design components with a controlled density and customized internal structure. The creation of new polymers and polymer composites allow for even greater control over the mechanical properties of AM parts. One of the key reasons to explore AM, is to bring about a new paradigm in part design, where materials can be strategically optimized in a way that conventional subtractive methods cannot achieve. The two processes investigated in my research were the Fused Deposition Modeling (FDM) process and the Direct Ink Write (DIW) process. The objectives of the research were to determine the impact of in-fill density and morphology on the mechanical properties of FDM parts, and to determine if DIW printed samples could be produced where the filament diameter was varied while the overall density remained constant.

  7. A Fundamental Study of Laser Beam Welding Aluminum-Lithium Alloy 2195 for Cryogenic Tank Applications

    NASA Technical Reports Server (NTRS)

    Martukanitz, R. P.; Jan. R.

    1996-01-01

    Based on the potential for decreasing costs of joining stiffeners to skin by laser beam welding, a fundamental research program was conducted to address the impediments identified during an initial study involving laser beam welding of aluminum-lithium alloys. Initial objectives of the program were the identification of governing mechanism responsible for process related porosity while establishing a multivariant relationship between process parameters and fusion zone geometry for laser beam welds of alloy 2195. A three-level fractional factorial experiment was conducted to establish quantitative relationships between primary laser beam processing parameters and critical weld attributes. Although process consistency appeared high for welds produced during partial completion of this study, numerous cracks on the top-surface of the welds were discovered during visual inspection and necessitated additional investigations concerning weld cracking. Two experiments were conducted to assess the effect of filler alloy additions on crack sensitivity: the first experiment was used to ascertain the effects of various filler alloys on cracking and the second experiment involved modification to process parameters for increasing filler metal dilution. Results indicated that filler alloys 4047 and 4145 showed promise for eliminating cracking.

  8. Fundamental ecology is fundamental.

    PubMed

    Courchamp, Franck; Dunne, Jennifer A; Le Maho, Yvon; May, Robert M; Thébaud, Christophe; Hochberg, Michael E

    2015-01-01

    The primary reasons for conducting fundamental research are satisfying curiosity, acquiring knowledge, and achieving understanding. Here we develop why we believe it is essential to promote basic ecological research, despite increased impetus for ecologists to conduct and present their research in the light of potential applications. This includes the understanding of our environment, for intellectual, economical, social, and political reasons, and as a major source of innovation. We contend that we should focus less on short-term, objective-driven research and more on creativity and exploratory analyses, quantitatively estimate the benefits of fundamental research for society, and better explain the nature and importance of fundamental ecology to students, politicians, decision makers, and the general public. Our perspective and underlying arguments should also apply to evolutionary biology and to many of the other biological and physical sciences.

  9. Optimization of PECVD Chamber Cleans Through Fundamental Studies of Electronegative Fluorinated Gas Discharges.

    NASA Astrophysics Data System (ADS)

    Langan, John

    1996-10-01

    The predominance of multi-level metalization schemes in advanced integrated circuit manufacturing has greatly increased the importance of plasma enhanced chemical vapor deposition (PECVD) and in turn in-situ plasma chamber cleaning. In order to maintain the highest throughput for these processes the clean step must be as short as possible. In addition, there is an increasing desire to minimize the fluorinated gas usage during the clean, while maximizing its efficiency, not only to achieve lower costs, but also because many of the gases used in this process are global warming compounds. We have studied the fundamental properties of discharges of NF_3, CF_4, and C_2F6 under conditions relevant to chamber cleaning in the GEC rf reference cell. Using electrical impedance analysis and optical emission spectroscopy we have determined that the electronegative nature of these discharges defines the optimal processing conditions by controlling the power coupling efficiency and mechanisms of power dissipation in the discharge. Examples will be presented where strategies identified by these studies have been used to optimize actual manufacturing chamber clean processes. (This work was performed in collaboration with Mark Sobolewski, National Institute of Standards and Technology, and Brian Felker, Air Products and Chemicals, Inc.)

  10. A Study of 8 Fundamental Moral Characteristics among Thai Undergraduate Students

    ERIC Educational Resources Information Center

    Ngammuk, Patariya

    2011-01-01

    The objective of this study is to explore the eight fundamental moral characteristics of undergraduate students in order to benefit instructional model development. The eight moral characteristics are diligence, frugality, honesty, discipline, politeness, cleanliness, unity and generosity. The study findings rank these eight moral characteristics…

  11. Fundamental mechanistic studies in formic acid decomposition on transition metal surfaces

    NASA Astrophysics Data System (ADS)

    Mavrikakis, Manos

    2014-03-01

    Formic acid (HCOOH) is a simple molecule that is an abundant product of biomass processing and can serve as an internal source of hydrogen for oxygen removal and upgrading of biomass to chemicals and fuels. In addition, HCOOH can be used as a fuel for low temperature direct fuel cells. We present a systematic study of the HCOOH decomposition reaction mechanism starting from first-principles and including reactivity experiments and microkinetic modeling. In particular, periodic self-consistent Density Functional Theory (DFT) calculations are performed to determine the stability of reactive intermediates and activation energy barriers of elementary steps. Pre-exponential factors are determined from vibrational frequency calculations. Mean-field microkinetic models are developed and calculated reaction rates and reaction orders are then compared with experimentally measured ones. These comparisons provide useful insights on the nature of the active site, most-abundant surface intermediates as a function of reaction conditions and feed composition. Trends across metals on the fundamental atomic-scale level up to selectivity trends will be discussed. Finally, we identify from first-principles alloy surfaces, which may possess better catalytic properties for selective dehydrogenation of HCOOH than monometallic surfaces, thereby guiding synthesis towards promising novel catalytic materials. Work supported as part of the Institute of Atom-efficient Chemical Transformation (IACT), an Energy Frontier Research Center funded by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences.

  12. Fundamental study on the application of liquid crystals to actuator devices

    NASA Astrophysics Data System (ADS)

    Zhou, Yuan; Tsuji, Tomohiro; Chono, Shigeomi

    2016-07-01

    In a fundamental study to develop liquid crystal microactuators, we prepared a sandwich cell with a movable upper plate and used backflow induced by applying repetitively a rectangular wave voltage to drive the upper plate in its plane. We used 4-cyano-4'-pentyl biphenyl, a low-molar-mass nematic liquid crystal. The speed of the plate depends significantly on the frequency of the applied voltage. With specific settings of applied voltage, duty ratio, plate gap, and upper plate mass, the speed increases with increasing frequency, attaining a maximum value of 120 μm/s at 175 Hz. Further increases in frequency, however, produce a gradual decrease in plate speed because the molecules of the liquid crystal respond too slowly to the change in voltage at the higher frequencies. In addition, to expand the field of application of liquid crystal actuators, we performed an experiment to control the direction of movement of the upper plate by patterning the electrodes and the alignment layer to govern the orientation of molecules at the walls. The plate changes its direction smoothly with quick responses at each switching, but its speed is reduced compared with the unidirectional actuators over the entire frequency range.

  13. A Study of Thermal Analyses and Fundamental Combustion Characteristics for Thermal Utility with Biomass Volatile Matter

    NASA Astrophysics Data System (ADS)

    Ida, Tamio; Namba, Kunihiko; Sano, Hiroshi

    Based on un-use biomass utilities, Carbonized technology is noticed as material utilities and solid fuel. Therefore, this technology is tackling by national project as large-scale utilities. But, this technology is dehydrated volatiles matter during carbonized from biomass. Especially, Woody tar into one of volatile matter has vicious handling to get into trouble in carbonized equipment. In this study, we propose to get fundamental knowledge for effective thermal utility through thermal decompositions and fundamental combustion properties on experimental results. Woody tar has high caloric value (approximately 30MJ/kg) and high carbon ration. On the other hand, a woody vinegar liquid has thermal decomposition property close to water property with heat absorption as evaporation latent heat of water. In fundamental combustion experimental result, a woody tar has fl ammable combustion and surface combustion. Especially, a total combustion and ignition time properties has hyperbola relation to environment temperatures in furnace.

  14. Fundamentally updating fundamentals.

    PubMed

    Armstrong, Gail; Barton, Amy

    2013-01-01

    Recent educational research indicates that the six competencies of the Quality and Safety Education for Nurses initiative are best introduced in early prelicensure clinical courses. Content specific to quality and safety has traditionally been covered in senior level courses. This article illustrates an effective approach to using quality and safety as an organizing framework for any prelicensure fundamentals of nursing course. Providing prelicensure students a strong foundation in quality and safety in an introductory clinical course facilitates early adoption of quality and safety competencies as core practice values.

  15. Fundamental study of the austenite formation and decomposition in low-silicon, aluminum added TRIP steels

    NASA Astrophysics Data System (ADS)

    Garcia-Gonzalez, Jose Enrique

    2005-11-01

    TRIP (Transformation Induced Plasticity) steels are under development for automotive applications that require high strength and excellent formability. Conventional TRIP steels consist of a multiphase microstructure comprised of a ferrite matrix with a dispersion of bainite and metastable retained austenite. The high ductility exhibited by these steels results from the transformation of the metastable retained austenite to martensite during straining. In conventional TRIP steel processing, the multiphase microstructure is obtained by controlled cooling from the alpha + gamma region to an isothermal holding temperature. During this holding, bainite forms and carbon is rejected out into the austenite, which lowers the Ms temperature and stabilizes the austenite to room temperature. In this research project, a fundamental study of a low-Si, Mo-Nb added cold rolled TRIP steel with and without Al additions was conducted. In this study, the recrystallization of cold-rolled ferrite, the formation of austenite during intercritical annealing and the characteristics of the decomposition of the intercritically annealed austenite by controlled cooling rates were systematically assessed. Of special interest were: (i) the effect of the initial hot band microstructure, (ii) the formation of epitaxial ferrite during cooling from the intercritical annealing temperature to the isothermal holding temperature, (iii) the influence of the intercritically annealed austenite on the formation of bainite during the isothermal holding temperature, and (iv) the influence of the processing variables on the type, amount, composition and stability of the retained austenite. During this research study, techniques such as OM, SEM, EBSD, TEM, XRD and Magnetometry were used to fully characterize the microstructures. Furthermore, a Gleeble 3500 unit at US Steel Laboratories was used for dilatometry studies and to simulate different CGL processing routes, from which specimens were obtained to evaluate

  16. Damage analysis and fundamental studies. Quarterly progress report, October-December 1980

    SciTech Connect

    Not Available

    1981-02-01

    This report is the twelfth in a series of Quarterly Technical Progress Reports on Damage Analysis and Fundamental Studies (DAFS) which is one element of the Fusion Reactor Materials Program, conducted in support of the Magnetic Fusion Energy Program of the US Department of Energy. The first eight reports in this series were numbered DOE/ET-0065/1 through 8.

  17. Fundamental Frequency Variation with an Electrolarynx Improves Speech Understanding: A Case Study

    ERIC Educational Resources Information Center

    Watson, Peter J.; Schlauch, Robert S.

    2009-01-01

    Purpose: This study examined the effect of fundamental frequency (F0) variation on the intelligibility of speech in an alaryngeal talker who used an electrolarynx (EL). Method: One experienced alaryngeal talker produced variable F0 and a constant F0 with his EL as he read sentences aloud. As a control, a group of sentences with variable F0 was…

  18. Organic Chemistry Educators' Perspectives on Fundamental Concepts and Misconceptions: An Exploratory Study

    ERIC Educational Resources Information Center

    Duis, Jennifer M.

    2011-01-01

    An exploratory study was conducted with 23 organic chemistry educators to discover what general chemistry concepts they typically review, the concepts they believe are fundamental to introductory organic chemistry, the topics students find most difficult in the subject, and the misconceptions they observe in undergraduate organic chemistry…

  19. First Principles Studies of Tapered Silicon Nanowires: Fundamental Insights and Practical Applications

    NASA Astrophysics Data System (ADS)

    Wu, Zhigang

    2008-03-01

    Nanowires (NWs) are often observed experimentally to be tapered rather than straight-edged, with diameters (d) shrinking by as much as 1 nm per 10 nm of vertical growth. Previous theoretical studies have examined the electronic properties of straight-edged nanowires (SNWs), although the effects of tapering on quantum confinement may be of both fundamental and practical importance. We have employed ab initio calculations to study the structural and electronic properties of tapered Si NWs. As one may expect, tapered nanowires (TNWs) possess axially-dependent electronic properties; their local energy gaps vary along the wire axis, with the largest gap occurring at the narrowest point of the wire. In contrast to SNWs, where confinement tends to shift valence bands more than conduction bands away from the bulk gap, the unoccupied states in TNWs are much more sensitive to d than the occupied states. In addition, tapering causes the band-edge states to be spatially separated along the wire axis, a consequence of the interplay between a strong variation in quantum confinement strength with diameter and the tapering-induced charge transfer. This property may be exploited in electronic and optical applications, for example, in photovoltaic devices where the separation of the valence and conduction band states could be used to transport excited charges during the thermalization process. In order to gain insight into TNW photovoltaic properties, we have also carried out calculations of the dipole matrix elements near the band edges as well as the role of metal contacts on TNW electronic properties. Finally, a combination of ab initio total energy calculations and classical molecular dynamics (MD) simulations are employed to suggest a new technique for bringing nanoscale objects together to form ordered, ultra high-aspect ratio nanowires. This work was supported in part by the U.S. Department of Energy under Contract No. DE-AC02-05CH11231.

  20. A spectroscopic study of southern (candidate) γ Doradus stars. II. Detailed abundance analysis and fundamental parameters

    NASA Astrophysics Data System (ADS)

    Bruntt, H.; De Cat, P.; Aerts, C.

    2008-02-01

    Context: The γ Doradus stars are a recent class of variable main sequence F-type stars located on the red edge of the Cepheid instability strip. They pulsate in gravity modes, and this makes them particularly interesting for detailed asteroseismic analysis, which can provide fundamental knowledge of properties near the convective cores of intermediate-mass main sequence stars. Aims: To improve current understanding of γ Dor stars through theoretical modelling, additional constraints are needed. Our aim is to estimate the fundamental atmospheric parameters and determine the chemical composition of these stars. Detailed analyses of single stars have previously suggested links to Am and λ Boo stars, so we wish to explore this interesting connection between chemical peculiarity and pulsation. Methods: We analysed a sample of γ Dor stars for the first time, including nine bona fide and three candidate members of the class. We determined the fundamental atmospheric parameters and compared the abundance pattern with other A-type stars. We used the semi-automatic software package VWA for the analysis. This code relies on the calculation of synthetic spectra and thus takes line-blending into account. This is important because of the fast rotation in some of the sample stars, and we made a thorough analysis of how VWA performs when increasing v sin i. We obtained good results in agreement with previously derived fundamental parameters and abundances in a few selected reference stars with properties similar to the γ Dor stars. Results: We find that the abundance pattern in the γ Dor stars is not distinct from the constant A- and F-type stars we analysed. Appendices A and B are only available in electronic form at http://www.aanda.org

  1. Fundamental study about CO2 laser welding of titanium aluminide intermetallic compound

    NASA Astrophysics Data System (ADS)

    Kuwahara, Gaku; Yamaguchi, Shigeru; Nanri, Kenzo; Ootani, Masanori; Tetsuka, Masato; Seto, Sachio; Arai, Mikiya; Fujioka, Tomoo

    2000-11-01

    Titanium aluminide intermetallic compound is attracting attentions as heat-resistant and high-specific strength material in the next generation, especially, it is promising material in the field of aerospace components. Conventional machining process including welding, however, can be hardly applied due to its very low ductility. The objective of this study, as a first stage, is to find out paying attention to crack and hardness the fundamental good conditions of the bead-on-plate welding of TiAl intermetallic compound using CO2 laser irradiation. In the experiment, we used the casting gamma titanium aluminide contained iron, vanadium and boron with a thickness of 2mm. We carried out bead-on-plate laser welding in the titanium aluminide material in inert gas environment filled with argon. We measured fused depth, Vickers hardness, transverse crack numbers and so on as major parameters of welding speed from 1000 to 4600 mm/min and initial temperature of specimen from R.T. to 873 K with a beam spot size of 0.5 mm and an output power of 1.5 kW. In addition, the specimens were analyzed by Electron Probe X-ray Micro Analyzer, Energy Dispersive X-ray Spectroscopy and X-ray Diffractometry. As a result of experiments, transverse crack-free welding was achieved, when initial temperature was at 873 K. In every condition, the value of Vickers hardness of fused zone increased compared with base. We think the reason of it is an increase of (alpha) 2(Ti3Al) phase, which is caused by rapid cooling, taking in Oxygen, fine structure and so on.

  2. Feasibility Study for a Plasma Dynamo Facility to Investigate Fundamental Processes in Plasma Astrophysics. Final report

    SciTech Connect

    Forest, Cary B.

    2013-09-19

    The scientific equipment purchased on this grant was used on the Plasma Dynamo Prototype Experiment as part of Professor Forest's feasibility study for determining if it would be worthwhile to propose building a larger plasma physics experiment to investigate various fundamental processes in plasma astrophysics. The initial research on the Plasma Dynamo Prototype Experiment was successful so Professor Forest and Professor Ellen Zweibel at UW-Madison submitted an NSF Major Research Instrumentation proposal titled "ARRA MRI: Development of a Plasma Dynamo Facility for Experimental Investigations of Fundamental Processes in Plasma Astrophysics." They received funding for this project and the Plasma Dynamo Facility also known as the "Madison Plasma Dynamo Experiment" was constructed. This experiment achieved its first plasma in the fall of 2012 and U.S. Dept. of Energy Grant No. DE-SC0008709 "Experimental Studies of Plasma Dynamos," now supports the research.

  3. Fundamental Symmetries and Interactions Studied with Radioactive Isotopes in Atom Traps

    SciTech Connect

    Wilschut, H.W.

    2005-11-21

    The structure of certain nuclei and atoms allow one to study fundamental symmetries and interactions. In this review we consider the search for Time-Reversal invariance Violation (TRV). We consider two options: TRV in {beta} decay or the search for the forbidden Electric Dipole Moment (EDM). In both cases atomic trapping can be an appropriate tool. For {beta} decay radioactive isotopes are necessary, but also for EDM searches they appear to be useful.

  4. Real-Time X-Ray Transmission Microscopy for Fundamental Studies Solidification

    NASA Technical Reports Server (NTRS)

    Curreri, Peter A.; Kaukler, William F.; Sen, Subhayu; Peters, Palmer

    1998-01-01

    High resolution real-time X-ray Transmission Microscopy, XTM, has been applied to obtain information fundamental to solidification of optically opaque metallic systems. We have previously reported the measurement of solute profile in the liquid, phase growth, and detailed solid-liquid interfacial morphology of aluminum based alloys with exposure times less than 2 seconds. Recent advances in XTM furnace design have provided an increase in real-time magnification (during solidification) for the XTM from 4OX to 16OX. The increased magnification has enabled for the first time the XTM imaging of real-time growth of fibers and particles with diameters of 5 micrometers. We have applied this system to study of the kinetics of formation and morphological evolution of secondary fibers and particles in Al-Bi monotectic alloys to observe a previously unreported velocity dependent thermo-capillary depletion mechanism for Bi rich liquid which can penetrate many fiber diameters into the solid-liquid interface. In this talk we will discuss application of the XTM to the study the fundamentals of monotectic and eutectic solidification, the enhancement of XTM data with precise solid liquid interfacial temperature and thermal gradient measurement techniques, and the application of this technology to the study of the fundamentals of solidification in microgravity,

  5. A Study of Additional Costs of Second Language Instruction.

    ERIC Educational Resources Information Center

    McEwen, Nelly

    A study was conducted whose primary aim was to identify and explain additional costs incurred by Alberta, Canada school jurisdictions providing second language instruction in 1980. Additional costs were defined as those which would not have been incurred had the second language program not been in existence. Three types of additional costs were…

  6. Fundamental Studies of the Durability of Materials for Interconnects in Solid Oxide Fuel Cells

    SciTech Connect

    Frederick S. Pettit; Gerald H. Meier

    2006-06-30

    Ferritic stainless steels are a leading candidate material for use as an SOFC interconnect, but have the problem of forming volatile chromia species that lead to cathode poisoning. This project has focused both on optimization of ferritic alloys for SOFC applications and evaluating the possibility of using alternative materials. The initial efforts involved studying the oxidation behavior of a variety of chromia-forming ferritic stainless steels in the temperature range 700-900 C in atmospheres relevant to solid oxide fuel cell operation. The alloys exhibited a wide variety of oxidation behavior based on composition. A method for reducing the vaporization is to add alloying elements that lead to the formation of a thermally grown oxide layer over the protective chromia. Several commercial steels form manganese chromate on the surface. This same approach, combined with observations of TiO{sub 2} overlayer formation on the chromia forming, Ni-based superalloy IN 738, has resulted in the development of a series of Fe-22 Cr-X Ti alloys (X=0-4 wt%). Oxidation testing has indicated that this approach results in significant reduction in chromia evaporation. Unfortunately, the Ti also results in accelerated chromia scale growth. Fundamental thermo-mechanical aspects of the durability of solid oxide fuel cell (SOFC) interconnect alloys have also been investigated. A key failure mechanism for interconnects is the spallation of the chromia scale that forms on the alloy, as it is exposed to fuel cell environments. Indentation testing methods to measure the critical energy release rate (Gc) associated with the spallation of chromia scale/alloy systems have been evaluated. This approach has been used to evaluate the thermomechanical stability of chromia films as a function of oxidation exposure. The oxidation of pure nickel in SOFC environments was evaluated using thermogravimetric analysis (TGA) to determine the NiO scaling kinetics and a four-point probe was used to measure

  7. Fundamental Study on the Effect of High Frequency Vibration on Ride Comfort

    NASA Astrophysics Data System (ADS)

    Nakagawa, Chizuru; Shimamune, Ryohei; Watanabe, Ken; Suzuki, Erimitsu

    To develop a more suitable method of evaluating ride comfort of high speed trains, a fundamental study was conducted on sensitivity of passengers to various frequencies of vibration with respect to ride comfort. Experiments were performed on 55 subjects using an electrodynamic vibration system that can generate vibrations in the frequency range of 1 to 80 Hz in the vertical direction. Results of experiments indicated that the subjects tend to experience greater discomfort when exposed to high frequency vibrations than that presumed by the conventional Japanese ride comfort assessment method, the "Ride Comfort Level."

  8. Study on thermal effects & sulfurized additives, in lubricating greases

    NASA Astrophysics Data System (ADS)

    Shah, Ami Atul

    Lithium Base grease constitutes about 50% of market. The greases are developed to be able to work in multiple working conditions and have longer working life. Greases with extreme pressure additives and anti-wear additives have been developed as a solution to many of the applications. These developed greases are tested under ASTM D2266 testing conditions to meet the requirements. The actual working conditions, although, differ than the real testing conditions. The loading, speed and temperature conditions can be more harsh, or fluctuating in nature. The cyclic nature of the parameters cannot be directly related to the test performance. For this purpose studies on the performance under spectrum loading, variable speed and fluctuating temperature must be performed. This study includes tests to understand the effect of thermal variation on some of the most commonly used grease additives that perform well under ASTM D2266 testing conditions. The studied additives include most widely used industrial extreme pressure additive MoS2. Performance of ZDDP which is trying to replace MoS2 in its industrial applications has also been studied. The tests cover study of extreme pressure, anti-wear and friction modifier additives to get a general idea on the effects of thermal variation in three areas. Sulphur is the most common extreme pressure additive. Sulphur based MoS 2 is extensively used grease additive. Study to understand the tribological performance of this additive through wear testing and SEM/EDX studies has been done. This performance is also studied for other metallic sulfides like WS2 and sulphur based organic compound. The aim is to study the importance of the type of bond that sulphur shares in its additive's structure on its performance. The MoS2 film formation is found to be on the basis of the FeS formation on the substrate and protection through sacrificial monolayer deposition of the MoS2 sheared structure. The free Mo then tends to oxidise. An attempt to

  9. Fundamental Study of Micro-Defects in Electropolished EB-Welded and Hydroformed SRF Accelerating Structures

    SciTech Connect

    Sumption, Mike

    2014-08-29

    In the area of niobium elecropolishing fundamentals, we focused on understanding the influence of the surface topology, and geometry (with effects from gravity included. The formation of a viscous film is essential for the electropolishing process to take place. The exact nature and composition of the film formed on niobium is still unknown because of its solubility in the electrolyte. Extensive pitting may take place at surface where a stable film cannot form. This has to be taken into consideration while determining the speed with which the SRF cavities are rotated while EP. Hydrodynamic aspects must be taken into consideration while optimizing the polishing parameters. There is improvement in surface finish with polishing time. There is a huge change in surface quality when the EP time is increased from 2 hours to 4 hours but not much change takes place when the time is further increased to 6 hours. So keeping the economic points in view, about 100 um defect layer removal may be sufficient to get the desired performance. In the area of Electropolishing of untreated and treated niobium with Weld Joints we studied untreated and treated Nb, especially for the heat affected areas next to welded bumps, electropolished for different durations. The electropolishing of the untreated Nb caused the formation of pits on the surface at about 15 min but they disappeared when the electropolishing duration was more than 15 min. Electropolishing for 120 min smoothened the surface of untreated Nb by levelling the surface, but the severe formation of pits on the whole surface was found after 240 min. The treatment of Nb significantly changed the Nb surface morphology which was covered by grains of different size that looked light or dark in the optical microscope. The treated Nb was susceptible to pitting during the entire electropolishing starting from 15 min and the dark grains had more susceptibility to pitting than the light grains. In addition, electropolishing for 240 min

  10. CrossFit athletes exhibit high symmetry of fundamental movement patterns. A cross-sectional study

    PubMed Central

    Tafuri, Silvio; Notarnicola, Angela; Monno, Antonello; Ferretti, Francesco; Moretti, Biagio

    2016-01-01

    Summary Background even if CrossFit training programs accounted actually more than 7500 gyms affiliated in the USA and more than 2000 in Europe and involved today more than 1 million of people, actually there were not several studies about the effect of the CrossFit on the health and sport performance. The aim of these research was to evaluate the performance in 7 fundamental movement patterns using a standardized methods, the Functional Movement Screen (FMS). Methods we enrolled three groups of athletes (age 17–40 years; >6 months of training programs): CrossFitters, body builders and professional weightlifters. FMS test was performed to all people enrolled. Scores of FMS test was examined comparing three groups. Results no differences in the three groups were showed in the mean score values of each test and in total score, except for shoulder mobility test (higher among CrossFitters) and trunk stability push-up test (higher among weightlifter). Agreement between the test performed on the two sides was higher in CrossFit groups for hurdle step (93.2%), in line lung (86%), rotary stability test (95.3%) and shoulder mobility (90.7%; p<0.001). Conclusions CrossFitters seem to have a high level of concordance in the scores achieved in bilateral test. CrossFit seems to produce marked symmetry in some fundamental movements compared to weightlifting and bodybuilding. PMID:27331045

  11. [Fundamental study on the development of a measuring device using an accelerometer].

    PubMed

    Toshiaki, Sekita; Shyo, Hasegawa; Iwao, Hayakawa

    2002-12-01

    It is important to clarify stomatognathic functions. To diagnose them, some measuring devices, such as MKG and the Gnatho-hexagraph, were developed. Such equipment, however, is not widely diffused, due to cost. The purpose of this fundamental study was to obtain information on position using an accelerometer. This system consists of a micro dual-axis accelerometer and a peripheral interface controller. Two-dimensional acceleration, velocity, and movement can be calculated by a computer. We examined the accuracy of this system using a laser measuring device. The result was as follows: The accuracy of the system was 0.03 (p-p values) using acceleration of gravity and a frequency of 72.5 Hz. In the present study, mandibular movements during chewing raisins were analyzed using this system. The new system demonstrated its value for analyzing mandibular movements.

  12. Status of efforts on fundamental and applied studies with tritium at RFNC-VNIIEF

    SciTech Connect

    Yukhimchuk, A.A.; Ilkaev, R.I.

    2015-03-15

    This paper gives an overview of the efforts in the field of fundamental and applied physics with tritium carried out with the participation of RFNC-VNIIEF in 2007-2013. New physical results in the study of muon-catalyzed fusion and neutron-excess nuclei are presented; a project of a new experiment on searching for a magnetic moment of the neutrino using a tritium source and helium detector is discussed. The description of a tritium support test-bed for a plasma focus-type neutron source with intensity of 10{sup 13} s{sup -1} is given. Results of studies in the area of interaction of hydrogen isotopes with structural materials such as nickel, stainless steels, high-strength austenitic alloys and alumina-based ceramics are summarized. (authors)

  13. [Scientific fundamentals of hippo- and riding therapy - a compilation of study results (author's transl)].

    PubMed

    Rieger, C

    1978-02-01

    The article surveys some of the scientific fundamentals of hippo- and riding therapy, and its methods using the characteristic horseback three dimensional rhythmic movement impulses for its therapeutic values, particularly in cerebral palsy. The influence of riding on posture and balance reactions, position of the pelvic, postures of head and trunk as well as rotatory movements was demonstrated in film studies using the cerebral palsied with different syndromes as an example. Electromyographic examinations of antagonistic muscle groups, kinesiologic analyses with the help of a video-recorder, as well as motor tests to evaluate coordination and balance control confirm the practical experience, i.e., that the hippo- and riding therapy has a positive influence on the neuromuscular dysfunction in cerebral movement disorders. A lasting improvement of motor and intellectual abilities was proven by a long-term study which also revealed that motivation was the driving force. PMID:564536

  14. Fundamental study of failure mechanisms of pressure vessels under thermo-mechanical cycling in multiphase environments

    NASA Astrophysics Data System (ADS)

    Penso Mula, Jorge Antonio

    Cracking and bulging in welded and internally lined pressure vessels that work in thermal-mechanical cycling services have been well known problems in the petrochemical, power and nuclear industries. Published literature and industry surveys show that similar problems have been occurring during the last 50 years. Understanding the causes of cracking and bulging would lead to improvements in the reliability of these pressure vessels. This study attempts to add information required for improving the knowledge and fundamental understanding of these problems. Cracking and bulging, most often in the weld areas, commonly experienced in delayed coking units (e.g. coke drums) in oil refineries are typical examples. The coke drum was selected for this study because of the existing field experience and past industrial investigation results that were available to serve as the baseline references for the analytical studies performed for this dissertation. Another reason for selecting the delayed coking units for this study was due to their high economical yields. Shutting down these units would cause a high negative economic impact on the refinery operations. Several failure mechanisms were hypothesized. The finite element method was used to analyze these significant variables and to verify the hypotheses. In conclusion, a fundamental explanation of the occurrence of bulging and cracking in pressure vessels in multiphase environments has been developed. Several important factors have been identified, including the high convection coefficient of the boiling layer during filling and quenching, the mismatch in physical, thermal and mechanical properties in the dissimilar weld of the clad plates and process conditions such as heating and quenching rate and warming time. Material selection for coke drums should consider not only fatigue strength but also corrosion resistance at high temperatures and low temperatures. Cracking occurs due to low cycle fatigue and corrosion. The FEA

  15. NMR Computational Studies of Solid Acidity/Fundamental Studies of Catalysis by Solid Acids

    SciTech Connect

    James F. Haw

    2008-06-28

    This project focused on catalysis by zeolites and the synergy of spectroscopic characterization and theoretical modeling. In collaboration with the Waroquier group in Belgium we used state-of-the-art quantum chemical simulations on a supramolecular model of both the HZSM-5 zeolite and the co-catalytic hydrocarbon pool species and calculated a full catalytic cycle (including all rate constants) for methanol-to-olefin (MTO) catalysis involving a hydrocarbon pool species. This work not only represents the most robust computational analysis of a successful MTO route to date, but it also succeeds in tying together the many experimental clues. That work was featured on the cover of Angewandte Chemie. More recently we elucidated several unsuspected roles for formaldehyde in methanol to olefin catalysis. Formaldehyde proves to be a key species responsible for both the growth of the catalytically active hydrocarbon pool and its inevitable aging into deactivated polycyclic aromatic species. The apparent inevitability of formaldehyde formation at high temperatures, in particular in contact with active metal or metal oxide surfaces, may put some fundamental limitations on the economic potential of conversion of methanol to olefins.

  16. A Long Journey in Lanthanide Chemistry: From Fundamental Crystallogenesis Studies to Commercial Anticounterfeiting Taggants.

    PubMed

    Guillou, Olivier; Daiguebonne, Carole; Calvez, Guillaume; Bernot, Kevin

    2016-05-17

    Lanthanide ions have unique physical properties and are essential for numerous technological devices. Indeed, much research has been undertaken in order to understand and optimize their luminescent behavior. From a chemical and more specific point of view, lanthanides can be used to build coordination polymers (CPs). CPs are materials in which metal ions are associated with organic molecules (ligands) to form extended networks. They present great structural diversity and a wide range of unique properties such as great porosity, strong catalytic activities, and original magnetic and luminescent behaviors. In this Account, we highlight recent research advances obtained by our team in the field of lanthanide-based CPs. However, rather than present a simple chronological description of successive investigations, we have chosen present our own experience in order to show how standard academic studies can be successfully turned into applied research and finally into a viable startup that commercializes these products as anticounterfieting taggants. A taggant is a compound that can be dispersed in a host matrix at parts per million rates for it to be labeled. Its economic advantages over traditional anticounterfeiting techniques (labels, chips, etc.) are its very low cost and its ability to label a raw material at every stage of its processing, unlike traditional techniques that label only the final product. It thus permits traceability of a given material over a wide range of suppliers/subcontractors/sellers or customers at every step of its life. After 15 years of fundamental crystallogenesis research, we identified a very stable phase of lanthanide-based CPs in which strong lanthanide luminescence can be observed. We investigated this phase further and showed that a heteronuclear approach can give access to billions of different compositions and makes it possible to turn these powders into taggants. After the creation of a startup, we refocused on fundamental studies

  17. Fundamental studies to develop certified reference material to calibrate spectrophotometer in the ultraviolet region

    NASA Astrophysics Data System (ADS)

    da Conceição, F. C.; Borges, P. P.; Gomes, J. F. S.

    2016-07-01

    Spectrophotometry is the technique used in a great number of laboratories around the world. Quantitative determination of a high number of inorganic, organic and biological species can be made by spectrophotometry using calibrated spectrophotometers. International standards require the use of optical filters to perform the calibration of spectrophotometers. One of the recommended materials is the crystalline potassium dichromate (K2Cr2O7), which is used to prepare solutions in specific concentrations for calibration or verification of spectrophotometers in the ultraviolet (UV) spectral regions. This paper presents the results concerning the fundamental studies for developing a certified reference material (CRM) of crystalline potassium dichromate to be used as standard of spectrophotometers in order to contribute to reliable quantitative analyses.

  18. Fundamental studies of methyl iodide adsorption in DABCO impregnated activated carbons.

    PubMed

    Herdes, Carmelo; Prosenjak, Claudia; Román, Silvia; Müller, Erich A

    2013-06-11

    Methyl iodide capture from a water vapor stream using 1,4-diazabicyclo[2.2.2]octane (DABCO)-impregnated activated carbons is, for the first time, fundamentally described here on the atomic level by means of both molecular dynamics and grand canonical Monte Carlo simulations. A molecular dynamics annealing strategy was adopted to mimic the DABCO experimental impregnation procedure in a selected slitlike carbon pore. Predictions, restricted to the micropore region, are made about the adsorption isotherms of methyl iodide, water, and nitrogen on both impregnated and bare activated carbon models. Experimental and simulated nitrogen adsorption isotherms are compared for the validation of the impregnation strategy. Selectivity analyses of the preferential adsorption toward methyl iodide over water are also reported. These simulated adsorption isotherms sum up to previous experimental studies to provide an enhanced picture for this adsorption system of widespread use at nuclear plant HVAC facilities for the capture of radioactive iodine compounds. PMID:23679202

  19. Fundamental Studies of Charge Migration and Delocalization Relevant to Solar Energy Conversion

    SciTech Connect

    Michael J. Therien

    2012-06-01

    This program aimed to understand the molecular-level principles by which complex chemical systems carry out photochemical charge separation, transport, and storage, and how these insights could impact the design of practical solar energy conversion and storage devices. Towards these goals, this program focused on: (1) carrying out fundamental mechanistic and transient dynamical studies of proton-coupled electron-transfer (PCET) reactions; (2) characterizing and interrogating via electron paramagnetic resonance (EPR) spectroscopic methods novel conjugated materials that feature large charge delocalization lengths; and (3) exploring excitation delocalization and migration, as well as polaron transport properties of meso-scale assemblies that are capable of segregating light-harvesting antennae, nanoscale wire-like conduction elements, and distinct oxidizing and reducing environments.

  20. Damage analysis and fundamental studies. Quarterly progress report, January-March 1980

    SciTech Connect

    Not Available

    1980-05-01

    The DAFS program element is a national effort composed of contributions from a number of National Laboratories and other government laboratories, universities, and industrial laboratories. It was organized by the Materials and Radiation Effects Branch, Office of Fusion Energy, DOE, and a Task Group on Damage Analysis and Fundamental Studies which operates under the auspices of that Branch. The purpose of this series of reports is to provide a working technical record of that effort for the use of the program participants, for the fusion energy program in general, and for the Department of Energy. This report is organized along topical lines in parallel to a Program Plan of the same title so that activities and accomplishments may be followed readily, relative to that Program Plan. Thus, the work of a given laboratory may appear throughout the report. The Table of Contents is annotated for the convenience of the reader.

  1. FUNDAMENTAL STUDIES OF IGNITION PROCESSES IN LARGE NATURAL GAS ENGINES USING LASER SPARK IGNITION

    SciTech Connect

    Azer Yalin; Morgan Defoort; Bryan Willson

    2005-01-01

    The current report details project progress made during the first quarterly reporting period of the DOE sponsored project ''Fundamental studies of ignition processes in large natural gas engines using laser spark ignition''. The goal of the overall research effort is to develop a laser ignition system for natural gas engines, with a particular focus on using fiber optic delivery methods. In this report we present our successful demonstration of spark formation using fiber delivery made possible though the use of novel coated hollow fibers. We present results of (high power) experimental characterizations of light propagation using hollow fibers using both a high power research grade laser as well as a more compact laser. Finally, we present initial designs of the system we are developing for future on-engine testing using the hollow fibers.

  2. Damage analysis and fundamental studies. Quarterly progress report, April-June 1980

    SciTech Connect

    Not Available

    1980-08-01

    The DAFS program element is a national effort composed of contributions from a number of National Laboratories and other government laboratories, universities, and industrial laboratories. It was organized by the Materials and Radiation Effects Branch, Office of Fusion Energy, DOE, and a Task Group on Damage Analysis and Fundamental Studies which operates under the auspices of that Branch. The purpose of this series of reports is to provide a working technical record of that effort for the use of the program participants, for the fusion energy program in general, and for the Department of Energy. This report is organized along topical lines in parallel to a Program Plan of the same title so that activities and accomplishments may be followed readily, relative to that Program Plan.

  3. Prediction of Fundamental Vibrational Frequencies and Infrared Intensities: a Benchmark Study

    NASA Astrophysics Data System (ADS)

    Vázquez, Juana; Harding, Michael E.; Stanton, John F.

    2011-06-01

    In this work we investigate the performance of second-order vibrational perturbation theory (VPT2) using force fields computed at the fc-CCSD(T) level in conjunction with different double-, triple-, and quadruple-ζ basis sets for the prediction of fundamental vibrational frequencies and infrared intensities. A benchmark study comprising more than thirty small and medium sized molecules illustrates the accuracy and limitations of the presented scheme. Atomic natural orbital (ANOY, Y=0,1,2) [J. Almlöf and P. R. Taylor, J. Chem. Phys. 86, 4070 (1987)] and correlation-consistent (cc-pVXZ, X=D,T,Q) [T. H. Dunning, Jr., J. Chem. Phys. 90, 1007 (1989)] basis sets.

  4. Fundamentals of clinical outcomes assessment for spinal disorders: study designs, methodologies, and analyses.

    PubMed

    Vavken, Patrick; Ganal-Antonio, Anne Kathleen B; Shen, Francis H; Chapman, Jens R; Samartzis, Dino

    2015-04-01

    Study Design A broad narrative review. Objective Management of spinal disorders is continuously evolving, with new technologies being constantly developed. Regardless, assessment of patient outcomes is key in understanding the safety and efficacy of various therapeutic interventions. As such, evidence-based spine care is an essential component to the armamentarium of the spine specialist in an effort to critically analyze the reported literature and execute studies in an effort to improve patient care and change clinical practice. The following article, part one of a two-part series, is meant to bring attention to the pros and cons of various study designs, their methodological issues, as well as statistical considerations. Methods An extensive review of the peer-reviewed literature was performed, irrespective of language of publication, addressing study designs and their methodologies as well as statistical concepts. Results Numerous articles and concepts addressing study designs and their methodological considerations as well as statistical analytical concepts have been reported. Their applications in the context of spine-related conditions and disorders were noted. Conclusion Understanding the fundamental principles of study designs and their methodological considerations as well as statistical analyses can further advance and improve future spine-related research.

  5. Superallowed Beta Decay Studies at TRIUMF --- Nuclear Structure and Fundamental Symmetries

    NASA Astrophysics Data System (ADS)

    Zganjar, E. F.; Achtzehn, T.; Albers, D.; Andreoiu, C.; Andreyev, A. N.; Austin, R. A. E.; Ball, G. C.; Behr, J. A.; Biosvert, G. C.; Bricault, P.; Bishop, S.; Chakrawarthy, R. S.; Churchman, R.; Cross, D.; Cunningham, E.; D'Auria, J. M.; Dombsky, M.; Finlay, P.; Garrett, P. E.; Grinyer, G. F.; Hackman, G.; Hanemaayer, V.; Hardy, J. C.; Hodgson, D. F.; Hyland, B.; Iacob, V.; Klages, P.; Koopmans, K. A.; Kulp, W. D.; Lassen, J.; Lavoie, J. P.; Leslie, J. R.; Linder, T.; MacDonald, J. A.; Mak, H.-B.; Melconian, D.; Morton, A. C.; Ormand, W. E.; Osborne, C. J.; Pearson, C. J.; Pearson, M. R.; Phillips, A. A.; Piechaczek, A.; Ressler, J.; Sarazin, F.; Savard, G.; Schumaker, M. A.; Scraggs, H. C.; Svensson, C. E.; Valiente-Dobon, J. J.; Towner, I. S.; Waddington, J. C.; Walker, P. M.; Wendt, K.; Wood, J. L.

    2007-04-01

    Precision measurement of the beta -decay half-life, Q-value, and branching ratio between nuclear analog states of Jpi = 0+ and T=1 can provide critical and fundamental tests of the Standard Model's description of electroweak interactions. A program has been initiated at TRIUMF-ISAC to measure the ft values of these superallowed beta transitions. Two Tz = 0, A > 60 cases, 74Rb and 62Ga, are presented. These are particularly relevant because they can provide critical tests of the calculated nuclear structure and isospin-symmetry breaking corrections that are predicted to be larger for heavier nuclei, and because they demonstrate the advance in the experimental precision on ft at TRIUMF-ISAC from 0.26% for 74Rb in 2002 to 0.05% for 62Ga in 2006. The high precision world data on experimental ft and corrected Ft values are discussed and shown to be consistent with CVC at the 10-4 level, yielding an average Ft = 3073.70(74) s. This Ft leads to Vud = 0.9737(4) for the up-down element of the Standard Model's CKM matrix. With this value and the Particle Data Group's 2006 values for Vus and Vub, the unitarity condition for the CKM matrix is met. Additional measurements and calculations are needed, however, to reduce the uncertainties in that evaluation. That objective is the focus of the continuing program on superallowed-beta decay at TRIUMF-ISAC.

  6. Tether fundamentals

    NASA Technical Reports Server (NTRS)

    Carroll, J. A.

    1986-01-01

    Some fundamental aspects of tethers are presented and briefly discussed. The effects of gravity gradients, dumbbell libration in circular orbits, tether control strategies and impact hazards for tethers are among those fundamentals. Also considered are aerodynamic drag, constraints in momentum transfer applications and constraints with permanently deployed tethers. The theoretical feasibility of these concepts are reviewed.

  7. Combustion Fundamentals Research

    NASA Technical Reports Server (NTRS)

    1983-01-01

    Increased emphasis is placed on fundamental and generic research at Lewis Research Center with less systems development efforts. This is especially true in combustion research, where the study of combustion fundamentals has grown significantly in order to better address the perceived long term technical needs of the aerospace industry. The main thrusts for this combustion fundamentals program area are as follows: analytical models of combustion processes, model verification experiments, fundamental combustion experiments, and advanced numeric techniques.

  8. A Fundamental Study of Smoldering with Emphasis on Experimental Design for Zero-G

    NASA Technical Reports Server (NTRS)

    Fernandez-Pello, Carlos; Pagni, Patrick J.

    1995-01-01

    A research program to study smoldering combustion with emphasis on the design of an experiment to be conducted in the space shuttle was conducted at the Department of Mechanical Engineering, University of California, Berkeley. The motivation of the research is the interest in smoldering both as a fundamental combustion problem and as a serious fire risk. Research conducted included theoretical and experimental studies that have brought considerable new information about smolder combustion, the effect that buoyancy has on the process, and specific information for the design of a space experiment. Experiments were conducted at normal gravity, in opposed and forward mode of propagation and in the upward and downward direction to determine the effect and range of influence of gravity on smolder. Experiments were also conducted in microgravity, in a drop tower and in parabolic aircraft flights, where the brief microgravity periods were used to analyze transient aspects of the problem. Significant progress was made on the study of one-dimensional smolder, particularly in the opposed-flow configuration. These studies provided enough information to design a small-scale space-based experiment that was successfully conducted in the Spacelab Glovebox in the June 1992 USML-1/STS-50 mission of the Space Shuttle Columbia.

  9. Fundamental measure density functional theory study of hard spheres solid-liquid interface

    NASA Astrophysics Data System (ADS)

    Warshavsky, Vadim

    2005-03-01

    Interfacial free energy is an important characteristic of solid-liquid interface as it is one of the crucial parameters in many formula of interface thermodynamics such the nucleation theory. Previously different aspects of crystal-melt interfaces were intensively studied with simulations [1,2,3], but theoretical studies with Density Functional Theories (DFT) are inconclusive [4,5]. In this report the structure of hard spheres fcc crystal-melt interfaces and the anisotropy of the interfacial free energies are studied using the Rosenfeld's Fundamental Measure DFT as such a functional leads to reliable coexistence results not only for the hard sphere system but also for the Lennard-Jones systems [6]. The parameters of interfacial density profile were calculated by a proper minimization procedure. For the equilibrium density profile the interfacial free energies were compared with simulation results. 1. R.L.Davidchak and B.B.Laird, Phys.Rev.Lett., 85, 4751(2000). 2. J.J. Hoyt, M. Asta and A. Karma, Phys.Rev.Lett., 86, 5530 (2001). 3. J.R.Morris and X.Song, J.Chem.Phys., 119, 3920 (2003). 4. W.A.Curtin, Phys.Rev.B, 39, 6775(1989). 5. R.Ohnesorge, H.Lowen, and H.Wagner, Phys.Rev.E, 50, 4801 (1994). 6. V.Warshavsky and X.Song, Phys.Rev.E, 69, 061113 (2004).

  10. Diamond and Hydrogenated Carbons for Advanced Batteries and Fuel Cells: Fundamental Studies and Applications.

    SciTech Connect

    Swain; Greg M.

    2009-04-13

    The original funding under this project number was awarded for a period 12/1999 until 12/2002 under the project title Diamond and Hydrogenated Carbons for Advanced Batteries and Fuel Cells: Fundamental Studies and Applications. The project was extended until 06/2003 at which time a renewal proposal was awarded for a period 06/2003 until 06/2008 under the project title Metal/Diamond Composite Thin-Film Electrodes: New Carbon Supported Catalytic Electrodes. The work under DE-FG02-01ER15120 was initiated about the time the PI moved his research group from the Department of Chemistry at Utah State University to the Department of Chemistry at Michigan State University. This DOE-funded research was focused on (i) understanding structure-function relationships at boron-doped diamond thin-film electrodes, (ii) understanding metal phase formation on diamond thin films and developing electrochemical approaches for producing highly dispersed electrocatalyst particles (e.g., Pt) of small nominal particle size, (iii) studying the electrochemical activity of the electrocatalytic electrodes for hydrogen oxidation and oxygen reduction and (iv) conducting the initial synthesis of high surface area diamond powders and evaluating their electrical and electrochemical properties when mixed with a Teflon binder.

  11. Radiation Hydrodynamic Simulations in the Planar Scheme for the Fundamental Studies of Shock Ignition

    NASA Astrophysics Data System (ADS)

    Dong, Yunsong; Yang, Jiamin; Song, Tianming; Zhu, Tuo; Huang, Chengwu

    2016-04-01

    As a fundamental and crucial research topic in the direct-driven inertial confinement fusion (ICF), especially for shock ignition (SI), investigation on the laser coupling with planar low-Z targets is beneficial for deep physical comprehension at the primary phase of SI. The production of the intense shock and the shock coalescence in the multi-layer targets, driven by the 3ω intense laser (351 nm the wavelength), were studied in detail with the 1D and 2D radiation hydrodynamic simulations. It was inferred that the 1D simulation would overrate the shock velocity and the ablation pressure of the spike; the coalescence time and the velocity of the coalescence shock depended evidently on the pulse shape and the start time of the spike. The present study can also provide a semi-quantitative reference for the design of the SI decomposition experiments on the Shenguang-III prototype laser facility. supported by the National High-Tech R&D Program (863 Program) of China and National Natural Science Foundation of China (Nos. 11205143, 11505167)

  12. Hydrate-phobic surfaces: fundamental studies in clathrate hydrate adhesion reduction.

    PubMed

    Smith, J David; Meuler, Adam J; Bralower, Harrison L; Venkatesan, Rama; Subramanian, Sivakumar; Cohen, Robert E; McKinley, Gareth H; Varanasi, Kripa K

    2012-05-01

    Clathrate hydrate formation and subsequent plugging of deep-sea oil and gas pipelines represent a significant bottleneck for deep-sea oil and gas operations. Current methods for hydrate mitigation are expensive and energy intensive, comprising chemical, thermal, or flow management techniques. In this paper, we present an alternate approach of using functionalized coatings to reduce hydrate adhesion to surfaces, ideally to a low enough level that hydrodynamic shear stresses can detach deposits and prevent plug formation. Systematic and quantitative studies of hydrate adhesion on smooth substrates with varying solid surface energies reveal a linear trend between hydrate adhesion strength and the practical work of adhesion (γ(total)[1 + cos θ(rec)]) of a suitable probe liquid, that is, one with similar surface energy properties to those of the hydrate. A reduction in hydrate adhesion strength by more than a factor of four when compared to bare steel is achieved on surfaces characterized by low Lewis acid, Lewis base, and van der Waals contributions to surface free energy such that the practical work of adhesion is minimized. These fundamental studies provide a framework for the development of hydrate-phobic surfaces, and could lead to passive enhancement of flow assurance and prevention of blockages in deep-sea oil and gas operations.

  13. Induced neural stem/precursor cells for fundamental studies and potential application in neurodegenerative diseases.

    PubMed

    Shen, Ting; Pu, Jiali; Zheng, Tingting; Zhang, Baorong

    2015-10-01

    Recent research has shown that defined sets of exogenous factors are sufficient to convert rodent and human somatic cells directly into induced neural stem cells or neural precursor cells (iNSCs/iNPCs). The process of transdifferentiation bypasses the step of a pluripotent state and reduces the risk of tumorigenesis and genetic instability while retaining the self-renewing capacity. This iNSC/iNPC technology has fueled much excitement in regenerative medicine, as these cells can be differentiated into target cells for re placement therapy for neurodegenerative diseases. Patients' somatic cell-derived iNSCs/iNPCs have also been proposed to serve as disease models with potential value in both fundamental studies and clinical applications. This review focuses on the mechanisms, techniques, and app lications of iNSCs/iNPCs from a series of related studies, as well as further efforts in designing novel strategies using iNSC/iNPC technology and its potential applications in neurodegenerative diseases.

  14. Correlational study of speakers' heights, weights, body surface areas, and speaking fundamental frequencies.

    PubMed

    Lass, N J

    1978-04-01

    The purpose of this investigation was to determine the relationship among speakers' heights, weights, body surface areas, and speaking fundamental frequencies. The recordings of 30 speakers' readings of a standard prose passage were analyzed by means of the Fundamental Frequency Indicator (FFI) to obtain their speaking fundamental frequency characteristics. The speakers' heights and weights were obtained by means of standard measurement procuedures, and their body surface areas were calculated. Pearson product-moment correlation coefficients, computed separately for men and women, indicated that speakers' heights, weights, and body surface areas were not significantly correlated with their speaking fundamental frequencies; female speakers showed a slight negative correlation while male speakers showed a low, positive trend. Implications of these findings and suggestions for future research are discussed.

  15. Benchmark Study of Industrial Needs for Additive Manufacturing in Finland

    NASA Astrophysics Data System (ADS)

    Lindqvist, Markku; Piili, Heidi; Salminen, Antti

    Additive manufacturing (AM) is a modern way to produce parts for industrial use. Even though the technical knowledge and research of AM processes are strong in Finland, there are only few industrial applications. Aim of this study is to collect practical knowledge of companies who are interested in industrial use of AM, especially in South-Eastern Finland. Goal of this study is also to investigate demands and requirements of applications for industrial use of AM in this area of Finland. It was concluded, that two of the reasons prohibiting wider industrial use of AM in Finland, are wrong expectations against this technology as well as lack of basic knowledge of possibilities of the technology. Especially, it was noticed that strong 3D-hype is even causing misunderstandings. Nevertheless, the high-level industrial know-how in the area, built around Finnish lumber industry is a strong foundation for the additive manufacturing technology.

  16. Racism in Interracial Dating: A Case Study in Southern Culture and Fundamentalism

    ERIC Educational Resources Information Center

    Rose, Stephanie Firebaugh; Firmin, Michael W.

    2016-01-01

    This article presents a case study of Bob Jones University (BJU), a fundamentalist Christian institution located in South Carolina that is known within the context of U.S. higher education for its conservatism on multiple levels. Our analysis traces the beliefs of the institution's founder and subsequent leaders, in addition to particular…

  17. Electrostatic Levitation for Studies of Additive Manufactured Materials

    NASA Technical Reports Server (NTRS)

    SanSoucie, Michael P.; Rogers, Jan R.; Tramel, Terri

    2014-01-01

    The electrostatic levitation (ESL) laboratory at NASA's Marshall Space Flight Center is a unique facility for investigators studying high temperature materials. The laboratory boasts two levitators in which samples can be levitated, heated, melted, undercooled, and resolidified. Electrostatic levitation minimizes gravitational effects and allows materials to be studied without contact with a container or instrumentation. The lab also has a high temperature emissivity measurement system, which provides normal spectral and normal total emissivity measurements at use temperature. The ESL lab has been instrumental in many pioneering materials investigations of thermophysical properties, e.g., creep measurements, solidification, triggered nucleation, and emissivity at high temperatures. Research in the ESL lab has already led to the development of advanced high temperature materials for aerospace applications, coatings for rocket nozzles, improved medical and industrial optics, metallic glasses, ablatives for reentry vehicles, and materials with memory. Modeling of additive manufacturing materials processing is necessary for the study of their resulting materials properties. In addition, the modeling of the selective laser melting processes and its materials property predictions are also underway. Unfortunately, there is very little data for the properties of these materials, especially of the materials in the liquid state. Some method to measure thermophysical properties of additive manufacturing materials is necessary. The ESL lab is ideal for these studies. The lab can provide surface tension and viscosity of molten materials, density measurements, emissivity measurements, and even creep strength measurements. The ESL lab can also determine melting temperature, surface temperatures, and phase transition temperatures of additive manufactured materials. This presentation will provide background on the ESL lab and its capabilities, provide an approach to using the ESL

  18. A Study of Additive Noise Model for Robust Speech Recognition

    NASA Astrophysics Data System (ADS)

    Awatade, Manisha H.

    2011-12-01

    A model of how speech amplitude spectra are affected by additive noise is studied. Acoustic features are extracted based on the noise robust parts of speech spectra without losing discriminative information. An existing two non-linear processing methods, harmonic demodulation and spectral peak-to-valley ratio locking, are designed to minimize mismatch between clean and noisy speech features. Previously studied methods, including peak isolation [1], do not require noise estimation and are effective in dealing with both stationary and non-stationary noise.

  19. Fundamental Study of Local Heat Transfer in Forced Convective Boiling of Ammonia on Vertical Flat Plate

    NASA Astrophysics Data System (ADS)

    Kim, Jeong-Hun; Arima, Hirofumi; Ikegami, Yasuyuki

    In the present study, the fundamental experiments that investigate characteristics of local heat transfer in forced convective boiling on vertical flat plate with 2-mm channel height are taken to realize plate type compact evaporator for OTEC or STEC. The experiments are performed with ammonia as the working fluid. The experiments are also carried out with the following test conditions; saturated pressure = 0.7, 0.8, 0.9 MPa, mass flux = 7.5, 10, 15 kg/(m2•s), heat flux = 15, 20, 25 kW/m2 and inlet quality = 0.1 ~ 0.4 [-]. The result shows that the wall superheated temperature of forced convective boiling is lower than that of pool boiling. And the heat transfer coefficient increases with an increase in quality and the decrease in the local heat flux and saturated pressure for prescribed experimental conditions. However, local heat transfer coefficients are not affected by mass fluxes in the prescribed experimental conditions. An empirical correlation that can predict the local heat transfer coefficient on vertical flat plate within experimental conditions is also proposed.

  20. Fundamental measure density functional theory study of liquid-vapor interface of dipolar and quadrupolar fluids.

    PubMed

    Warshavsky, V B; Zeng, X C

    2013-10-01

    We have studied interfacial structure and properties of liquid-vapor interfaces of dipolar fluids and quadrupolar fluids, respectively, using the classical density functional theory (DFT). Towards this end, we employ the fundamental measure DFT for a reference hard-sphere (HS) part of free energy and the modified mean field approximation for the correlation function of dipolar or quadrupolar fluid. At low temperatures we find that both the liquid-vapor interfacial density profile and orientational order parameter profile exhibit weakly damped oscillatory decay into the bulk liquid. At high temperatures the decay of interfacial density and order parameter profiles is entirely monotonic. The scaled temperature τ = 1 - T/T(c) that separates the two qualitatively different interfacial structures is in the range 0.10-0.15. At a given (dimensionless) temperature, increasing the dipolar or quadrupolar moment enhances the density oscillations. Application of an electric field (normal to the interface) will damp the oscillations. Likewise, at the given temperature, increasing the strength of any multipolar moment also increases the surface tensions while increasing the strength of the applied electric field will reduce the surface tensions. The results are compared with those based on the local-density approximations (LDA) for the reference HS part of free energy as well as with results of numerical experiments.

  1. Inverse oxide/metal catalysts in fundamental studies and practical applications: A perspective of recent developments

    DOE PAGES

    Rodriguez, José A.; Liu, Ping; Graciani, Jesús; Senanayake, Sanjaya D.; Grinter, David C.; Stacchiola, Dario; Hrbek, Jan; Fernández-Sanz, Javier

    2016-06-21

    Inverse oxide/metal catalysts have shown to be excellent systems for studying the role of the oxide and oxide–metal interface in catalytic reactions. These systems can have special structural and catalytic properties due to strong oxide–metal interactions difficult to attain when depositing a metal on a regular oxide support. Oxide phases that are not seen or are metastable in a bulk oxide can become stable in an oxide/metal system opening the possibility for new chemical properties. Using these systems, it has been possible to explore fundamental properties of the metal–oxide interface (composition, structure, electronic state), which determine catalytic performance in themore » oxidation of CO, the water–gas shift and the hydrogenation of CO2 to methanol. Recently, there has been a significant advance in the preparation of oxide/metal catalysts for technical or industrial applications. In conclusion, one goal is to identify methods able to control in a precise way the size of the deposited oxide particles and their structure on the metal substrate.« less

  2. Spectroscopic studies of magnesium plasma produced by fundamental and second harmonics of Nd:YAG laser

    NASA Astrophysics Data System (ADS)

    Haq, S. U.; Ahmat, L.; Mumtaz, M.; Shakeel, Hira; Mahmood, S.; Nadeem, A.

    2015-08-01

    In the present experimental work, laser induced magnesium plasma has been characterized using plasma parameters. The plasma has been generated by the fundamental (1064 nm) and second harmonics (532 nm) of Nd:YAG laser. The plasma parameters such as electron temperature and electron number density have been extracted using Boltzmann plot method and Stark broadened line profile, respectively. The laser irradiance dependence and spatial behavior of electron temperature and number density in laser induced magnesium plasma have been studied. The electron temperature as a function of laser irradiance (0.5 to 6.5 GW/cm2) ranges from (9.16-10.37) × 103 K and (8.5-10.1)× 103 K, and electron number density from (0.99-1.08) × 1016 cm-3 and (1.04-1.22) × 1016cm-3 for 1064 and 532 nm, respectively. These parameters exhibit fast increase at low laser irradiance and slow increase at high irradiance. The spatial distribution of electron temperature and electron number density shows same decreasing trend up to 2.25 mm from the target surface. The electron temperature and number density decrease from (9.5-8.6) × 103 K, (1.27-1.15) × 1016cm-3 and (10.56-8.85)× 103 K, (1.08-0.99) × 1016 cm-3 for 532 nm and 1064 nm laser ablation wavelengths, respectively.

  3. Microwave sanitization of color additives used in cosmetics: feasibility study.

    PubMed

    Jasnow, S B; Smith, J L

    1975-08-01

    Microwave exposure has been explored as a method of microbiologically sanitizing color additives used in cosmetic products. Selected microbiologically unacceptable cosmetic color additives, D&C red no. 7 Ca lake (certified synthetic organic color), carmine (natural organic color not subject to certification), and chromium hydroxide green (inorganic color not subject to certification), were submitted to microwave exposure. Gram-negative bacteria were eliminated, as verified by enrichment procedures, and levels of gram-positive bacteria were reduced. Generally, analytical and dermal safety studies indicated no significant alterations in physical, chemical, and toxicological properties of the colors. Sanitization was also successfully performed on other colors (D&C red no. 9 Ba lake, D&C red no. 12 Ba lake, D&C green no. 5, and FD&C red no. 4); initial physical and chemical tests were satisfactory. Results indicated that this method of sanitization is feasible and warrants further investigation.

  4. BIG FROG WILDERNESS STUDY AREA AND ADDITIONS, TENNESSEE AND GEORGIA.

    USGS Publications Warehouse

    Slack, John F.; Gazdik, Gertrude C.

    1984-01-01

    A mineral-resource survey was made of the Big Frog Wilderness Study Area and additions, Tennessee-Georgia. Geochemical sampling found traces of gold, zinc, copper, and arsenic in rocks, stream sediments, and panned concentrates, but not in sufficient quantities to indicate the presence of deposits of these metals. The results of the survey indicate that there is little promise for the occurrence of metallic mineral deposits within the study area. The only apparent resources are nonmetallic commodities including rock suitable for construction materials, and small amounts of sand and gravel; however, these commodities are found in abundance outside the study area. A potential may exist for oil and natural gas at great depths, but this cannot be evaluated by the present study.

  5. Recommended Protocol for Round Robin Studies in Additive Manufacturing

    PubMed Central

    Moylan, Shawn; Brown, Christopher U.; Slotwinski, John

    2016-01-01

    One way to improve confidence and encourage proliferation of additive manufacturing (AM) technologies and parts is by generating more high quality data describing the performance of AM processes and parts. Many in the AM community see round robin studies as a way to generate large data sets while distributing the cost among the participants, thereby reducing the cost to individual users. The National Institute of Standards and Technology (NIST) has conducted and participated in several of these AM round robin studies. While the results of these studies are interesting and informative, many of the lessons learned in conducting these studies concern the logistics and methods of the study and unique issues presented by AM. Existing standards for conducting interlaboratory studies of measurement methods, along with NIST’s experience, form the basis for recommended protocols for conducting AM round robin studies. The role of round robin studies in AM qualification, some of the limitations of round robin studies, and the potential benefit of less formal collaborative experiments where multiple factors, AM machine being only one, are varied simultaneously are also discussed. PMID:27274602

  6. A study on the fundamental mechanism and the evolutionary driving forces behind aerobic fermentation in yeast.

    PubMed

    Hagman, Arne; Piškur, Jure

    2015-01-01

    Baker's yeast Saccharomyces cerevisiae rapidly converts sugars to ethanol and carbon dioxide at both anaerobic and aerobic conditions. The later phenomenon is called Crabtree effect and has been described in two forms, long-term and short-term effect. We have previously studied under fully controlled aerobic conditions forty yeast species for their central carbon metabolism and the presence of long-term Crabtree effect. We have also studied ten steady-state yeast cultures, pulsed them with glucose, and followed the central carbon metabolism and the appearance of ethanol at dynamic conditions. In this paper we analyzed those wet laboratory data to elucidate possible mechanisms that determine the fate of glucose in different yeast species that cover approximately 250 million years of evolutionary history. We determine overflow metabolism to be the fundamental mechanism behind both long- and short-term Crabtree effect, which originated approximately 125-150 million years ago in the Saccharomyces lineage. The "invention" of overflow metabolism was the first step in the evolution of aerobic fermentation in yeast. It provides a general strategy to increase energy production rates, which we show is positively correlated to growth. The "invention" of overflow has also simultaneously enabled rapid glucose consumption in yeast, which is a trait that could have been selected for, to "starve" competitors in nature. We also show that glucose repression of respiration is confined mainly among S. cerevisiae and closely related species that diverged after the whole genome duplication event, less than 100 million years ago. Thus, glucose repression of respiration was apparently "invented" as a second step to further increase overflow and ethanol production, to inhibit growth of other microbes. The driving force behind the initial evolutionary steps was most likely competition with other microbes to faster consume and convert sugar into biomass, in niches that were semi-anaerobic.

  7. A fundamental study of contribution'' transport theory and channel theory applications

    SciTech Connect

    Williams, M.L.

    1992-01-01

    The objective of this three-year study is to develop a technique called channel theory'' that can be used in interpreting particle transport analysis such as frequently required in radiation shielding design and assessment. Channel theory is a technique used to provide insight into the mechanisms by which particles emitted from a source are transported through a complex system and register a response on some detector. It is based on the behavior of a pseudo particle called a contributon,'' which is the response carrier through space and energy channels that connect the source and detector. Contributons'' are those particles among all the ones contained in the system which will eventually contribute some amount of response to the detector. The specific goals of this projects are to provide a more fundamental theoretical understanding of the method, and to develop computer programs to apply the techniques to practical problems encountered in radiation transport analysis. The overall project can be divided into three components to meet these objectives: (a) Theoretical Development, (b) Code Development, and (c) Sample Applications. During the present third year of this study, an application of contributon theory to the analysis of radiation heating in a nuclear rocket has been completed, and a paper on the assessment of radiation damage response of an LWR pressure vessel and analysis of radiation propagation through space and energy channels in air at the Hiroshima weapon burst was accepted for publication. A major effort was devoted to developing a new Contributon Monte Carlo'' method, which can improve the efficiency of Monte Carlo calculations of radiation transport by tracking only contributons. The theoretical basis for Contributon Monte Carlo has been completed, and the implementation and testing of the technique is presently being performed.

  8. A fundamental study of ``contribution`` transport theory and channel theory applications. Progress report

    SciTech Connect

    Williams, M.L.

    1992-12-01

    The objective of this three-year study is to develop a technique called ``channel theory`` that can be used in interpreting particle transport analysis such as frequently required in radiation shielding design and assessment. Channel theory is a technique used to provide insight into the mechanisms by which particles emitted from a source are transported through a complex system and register a response on some detector. It is based on the behavior of a pseudo particle called a ``contributon,`` which is the response carrier through space and energy channels that connect the source and detector. ``Contributons`` are those particles among all the ones contained in the system which will eventually contribute some amount of response to the detector. The specific goals of this projects are to provide a more fundamental theoretical understanding of the method, and to develop computer programs to apply the techniques to practical problems encountered in radiation transport analysis. The overall project can be divided into three components to meet these objectives: (a) Theoretical Development, (b) Code Development, and (c) Sample Applications. During the present third year of this study, an application of contributon theory to the analysis of radiation heating in a nuclear rocket has been completed, and a paper on the assessment of radiation damage response of an LWR pressure vessel and analysis of radiation propagation through space and energy channels in air at the Hiroshima weapon burst was accepted for publication. A major effort was devoted to developing a new ``Contributon Monte Carlo`` method, which can improve the efficiency of Monte Carlo calculations of radiation transport by tracking only contributons. The theoretical basis for Contributon Monte Carlo has been completed, and the implementation and testing of the technique is presently being performed.

  9. A study on the fundamental mechanism and the evolutionary driving forces behind aerobic fermentation in yeast.

    PubMed

    Hagman, Arne; Piškur, Jure

    2015-01-01

    Baker's yeast Saccharomyces cerevisiae rapidly converts sugars to ethanol and carbon dioxide at both anaerobic and aerobic conditions. The later phenomenon is called Crabtree effect and has been described in two forms, long-term and short-term effect. We have previously studied under fully controlled aerobic conditions forty yeast species for their central carbon metabolism and the presence of long-term Crabtree effect. We have also studied ten steady-state yeast cultures, pulsed them with glucose, and followed the central carbon metabolism and the appearance of ethanol at dynamic conditions. In this paper we analyzed those wet laboratory data to elucidate possible mechanisms that determine the fate of glucose in different yeast species that cover approximately 250 million years of evolutionary history. We determine overflow metabolism to be the fundamental mechanism behind both long- and short-term Crabtree effect, which originated approximately 125-150 million years ago in the Saccharomyces lineage. The "invention" of overflow metabolism was the first step in the evolution of aerobic fermentation in yeast. It provides a general strategy to increase energy production rates, which we show is positively correlated to growth. The "invention" of overflow has also simultaneously enabled rapid glucose consumption in yeast, which is a trait that could have been selected for, to "starve" competitors in nature. We also show that glucose repression of respiration is confined mainly among S. cerevisiae and closely related species that diverged after the whole genome duplication event, less than 100 million years ago. Thus, glucose repression of respiration was apparently "invented" as a second step to further increase overflow and ethanol production, to inhibit growth of other microbes. The driving force behind the initial evolutionary steps was most likely competition with other microbes to faster consume and convert sugar into biomass, in niches that were semi

  10. Making intelligent systems team players: Additional case studies

    NASA Technical Reports Server (NTRS)

    Malin, Jane T.; Schreckenghost, Debra L.; Rhoads, Ron W.

    1993-01-01

    Observations from a case study of intelligent systems are reported as part of a multi-year interdisciplinary effort to provide guidance and assistance for designers of intelligent systems and their user interfaces. A series of studies were conducted to investigate issues in designing intelligent fault management systems in aerospace applications for effective human-computer interaction. The results of the initial study are documented in two NASA technical memoranda: TM 104738 Making Intelligent Systems Team Players: Case Studies and Design Issues, Volumes 1 and 2; and TM 104751, Making Intelligent Systems Team Players: Overview for Designers. The objective of this additional study was to broaden the investigation of human-computer interaction design issues beyond the focus on monitoring and fault detection in the initial study. The results of this second study are documented which is intended as a supplement to the original design guidance documents. These results should be of interest to designers of intelligent systems for use in real-time operations, and to researchers in the areas of human-computer interaction and artificial intelligence.

  11. A numerical study of fundamental shock noise mechanisms. Ph.D. Thesis - Cornell Univ.

    NASA Technical Reports Server (NTRS)

    Meadows, Kristine R.

    1995-01-01

    The results of this thesis demonstrate that direct numerical simulation can predict sound generation in unsteady aerodynamic flows containing shock waves. Shock waves can be significant sources of sound in high speed jet flows, on helicopter blades, and in supersonic combustion inlets. Direct computation of sound permits the prediction of noise levels in the preliminary design stage and can be used as a tool to focus experimental studies, thereby reducing cost and increasing the probability of a successfully quiet product in less time. This thesis reveals and investigates two mechanisms fundamental to sound generation by shocked flows: shock motion and shock deformation. Shock motion is modeled by the interaction of a sound wave with a shock. During the interaction, the shock wave begins to move and the sound pressure is amplified as the wave passes through the shock. The numerical approach presented in this thesis is validated by the comparison of results obtained in a quasi-one dimensional simulation with linear theory. Analysis of the perturbation energy demonstrated for the first time that acoustic energy is generated by the interaction. Shock deformation is investigated by the numerical simulation of a ring vortex interacting with a shock. This interaction models the passage of turbulent structures through the shock wave. The simulation demonstrates that both acoustic waves and contact surfaces are generated downstream during the interaction. Analysis demonstrates that the acoustic wave spreads cylindrically, that the sound intensity is highly directional, and that the sound pressure level increases significantly with increasing shock strength. The effect of shock strength on sound pressure level is consistent with experimental observations of shock noise, indicating that the interaction of a ring vortex with a shock wave correctly models a dominant mechanism of shock noise generation.

  12. Bence Jones proteins: Powerful tool for fundamental study of protein chemistry and pathophysiology

    SciTech Connect

    Stevens, F.J.; Schiffer, M.; Solomon, A.

    1991-12-31

    Bence Jones proteins are typically found in patients with monoclonal plasma cell or related B-cell immunoproliferative disorders. Because of their monoclonal origin and resulting chemical homogeneity much of the fundamental information on immunoglobulin structure came initially from their analysis. Amino acid analyses of these components revealed an N-terminal variable (V) and C-terminal constant (C) domain as well as the existence within the V domain of hypervariable segments that account for the specificity and diversity of antibodies. Over the past three decades, the primary structures of hundreds of light chains (complete and partial), from human and other sources, have been determined, aligned, and archived. Bence Jones proteins and V{sub L} dimers were the crystallizable homogeneous proteins which provided much of the early three-dimensional conformational data that helped explain the structural basis of antibody function. Remarkably, a single Bence Jones protein in two solvent systems (low and high ionic strength) exhibited significant differences in the interactions of the two monomeric subunits comprising the dimer, resulting in substantial variation in the structure of the antigen combining site under the two solution conditions. This observation led to a prediction that heterogeneity of domain interactions may contribute to antibody-antigen interactions. Experimental support for this hypothesis has come from comparisons of the detailed structures of antibody-antigen complexes. The interactions at the interface of the V{sub L} dimer are a function of primary structure and solution conditions. Study of these interactions has led to new information on the relationship between protein structure and function and, as discussed below, can account for specific pathophysiological properties associated with Bence Jones proteins.

  13. Spectroscopic studies of magnesium plasma produced by fundamental and second harmonics of Nd:YAG laser

    SciTech Connect

    Haq, S. U. Ahmat, L.; Mumtaz, M.; Nadeem, A.; Shakeel, Hira; Mahmood, S.

    2015-08-15

    In the present experimental work, laser induced magnesium plasma has been characterized using plasma parameters. The plasma has been generated by the fundamental (1064 nm) and second harmonics (532 nm) of Nd:YAG laser. The plasma parameters such as electron temperature and electron number density have been extracted using Boltzmann plot method and Stark broadened line profile, respectively. The laser irradiance dependence and spatial behavior of electron temperature and number density in laser induced magnesium plasma have been studied. The electron temperature as a function of laser irradiance (0.5 to 6.5 GW/cm{sup 2}) ranges from (9.16–10.37) × 10{sup 3 }K and (8.5–10.1)× 10{sup 3 }K, and electron number density from (0.99–1.08) × 10{sup 16} cm{sup −3} and (1.04–1.22) × 10{sup 16}cm{sup −3} for 1064 and 532 nm, respectively. These parameters exhibit fast increase at low laser irradiance and slow increase at high irradiance. The spatial distribution of electron temperature and electron number density shows same decreasing trend up to 2.25 mm from the target surface. The electron temperature and number density decrease from (9.5–8.6) × 10{sup 3 }K, (1.27–1.15) × 10{sup 16}cm{sup −3} and (10.56–8.85)× 10{sup 3 }K, (1.08–0.99) × 10{sup 16} cm{sup −3} for 532 nm and 1064 nm laser ablation wavelengths, respectively.

  14. RAMSEYS DRAFT WILDERNESS STUDY AREA AND ADDITION, VIRGINIA.

    USGS Publications Warehouse

    Lesure, Frank G.; Mory, Peter C.

    1984-01-01

    Mineral-resource surveys of the Ramseys Draft Wilderness Study Area and adjoining roadless area addition in George Washington National Forest in the western valley and ridge province, Augusta and Highland Counties, Virginia, were done. The surveys outlined three small areas containing anomalous amounts of copper, lead, and zinc related to stratabound red-bed copper mineralization, but these occurrences are not large and are not considered as having mineral-resource potential. The area contains abundant sandstone suitable for construction materials and shale suitable for making brick, tile, and other low-grade ceramic products, but these commodities occur in abundance outside the wilderness study area. Structural conditions are probably favorable for the accumulation of natural gas, but exploratory drilling has not been done sufficiently near the area to evaluate the gas potential.

  15. A Study of the Relationship between Reading, Computational, and Critical Thinking Skills and Academic Success in Fundamentals of Chemistry.

    ERIC Educational Resources Information Center

    Hurov, Janet Torrisi

    In spring 1987, a study was conducted at St. Louis Community College at Florissant Valley (Missouri) to identify the basic skills necessary for the successful completion of the course, "Fundamentals of Chemistry." The study evaluated the relationship between performance on the Nelson-Denny Reading Test (NDRT), the Numerical Reasoning subtest of…

  16. Fundamental studies of energy-and hole/electron- transfer in hydroporphyrin architectures

    SciTech Connect

    Bocian, David F.

    2014-08-20

    of spectra for naturally occurring and synthetic hydroporphyrins. The availability of such data should augment efforts in the design of light-harvesting systems where spectral coverage in the red and near-infrared regions is desired. Collectively, the proposed studies will provide fundamental insights into molecular properties, interactions, and processes relevant to the design of molecular architectures for solar-energy conversion. The accomplishment of these goals is only possible through a highly synergistic program that encompasses molecular design, synthesis, and characterization.

  17. Fundamental frequency and voice perturbation measures in smokers and non-smokers: An acoustic and perceptual study

    NASA Astrophysics Data System (ADS)

    Freeman, Allison

    This research examined the fundamental frequency and perturbation (jitter % and shimmer %) measures in young adult (20-30 year-old) and middle-aged adult (40-55 year-old) smokers and non-smokers; there were 36 smokers and 36 non-smokers. Acoustic analysis was carried out utilizing one task: production of sustained /a/. These voice samples were analyzed utilizing Multi-Dimensional Voice Program (MDVP) software, which provided values for fundamental frequency, jitter %, and shimmer %.These values were analyzed for trends regarding smoking status, age, and gender. Statistical significance was found regarding the fundamental frequency, jitter %, and shimmer % for smokers as compared to non-smokers; smokers were found to have significantly lower fundamental frequency values, and significantly higher jitter % and shimmer % values. Statistical significance was not found regarding fundamental frequency, jitter %, and shimmer % for age group comparisons. With regard to gender, statistical significance was found regarding fundamental frequency; females were found to have statistically higher fundamental frequencies as compared to males. However, the relationships between gender and jitter % and shimmer % lacked statistical significance. These results indicate that smoking negatively affects voice quality. This study also examined the ability of untrained listeners to identify smokers and non-smokers based on their voices. Results of this voice perception task suggest that listeners are not accurately able to identify smokers and non-smokers, as statistical significance was not reached. However, despite a lack of significance, trends in data suggest that listeners are able to utilize voice quality to identify smokers and non-smokers.

  18. Fundamental and applied studies in nanoparticle biomedical imaging, stabilization, and processing

    NASA Astrophysics Data System (ADS)

    Pansare, Vikram J.

    Nanoparticle carrier systems are gaining importance in the rapidly expanding field of biomedical whole animal imaging where they provide long circulating, real time imaging capability. This thesis presents a new paradigm in imaging whereby long wavelength fluorescent or photoacoustically active contrast agents are embedded in the hydrophobic core of nanocarriers formed by Flash NanoPrecipitation. The long wavelength allows for improved optical penetration depth. Compared to traditional contrast agents where fluorophores are placed on the surface, this allows for improved signal, increased stability, and molecular targeting capabilities. Several types of long wavelength hydrophobic dyes based on acene, cyanine, and bacteriochlorin scaffolds are utilized and animal results obtained for nanocarrier systems used in both fluorescent and photoacoustic imaging modes. Photoacoustic imaging is particularly promising due to its high resolution, excellent penetration depth, and ability to provide real-time functional information. Fundamental studies in nanoparticle stabilization are also presented for two systems: model alumina nanoparticles and charge stabilized polystyrene nanoparticles. Motivated by the need for stable suspensions of alumina-based nanocrystals for security printing applications, results are presented for the adsorption of various small molecule charged hydrophobes onto the surface of alumina nanoparticles. Results are also presented for the production of charge stabilized polystyrene nanoparticles via Flash NanoPrecipitation, allowing for the independent control of polymer molecular weight and nanoparticle size, which is not possible by traditional emulsion polymerization routes. Lastly, methods for processing nanoparticle systems are explored. The increasing use of nanoparticle therapeutics in the pharmaceutical industry has necessitated the development of scalable, industrially relevant processing methods. Ultrafiltration is particularly well suited for

  19. Fundamental study of photoresist dissolution with real time spectroscopic ellipsometry and interferometry

    NASA Astrophysics Data System (ADS)

    Burns, Sean D.; Schmid, Gerard M.; Trinque, Brian C.; Willson, James; Wunderlich, Jennifer; Tsiartas, Pavlos C.; Taylor, James C.; Burns, Ryan L.; Wilson, C. Grant

    2003-06-01

    The use of in situ spectroscopic ellipsometry (SE) is demonstrated as a technique for studying photoresist dissolution. Experiments carried out using a J.A.Woollam M-2000 ellipsometer and a custom built cell designed for in situ film measurements show that bulk dissolution rate measurements using the SE technique agree with dissolution rate data obtained using multiwavelength interferometry. SE is also demonstrated as a method for measuring thin film dissolution rates, water sorption, and films that swell. An additional focus of this work was the topic of interfacial "gel" layer formation during photoresist dissolution. Ellipsometry and interferometry were used to test several photoresist resins, with an emphasis on phenolic polymers. Single and multiple layer models were used to analyze the data, and were compared to model calculations predicting formation of a gel layer. For the materials studied, interfacial gel layer formation in low molecular weight phenolic polymers was not detected, within the resolution of the experimental techniques (< 15 nm).

  20. Developmental Changes in the Fundamental Frequency (f0) of Infants' Cries: A Study of Children with Autism Spectrum Disorder

    ERIC Educational Resources Information Center

    Esposito, Gianluca; Venuti, Paola

    2010-01-01

    Episodes of crying with higher fundamental frequency (f0) are perceived as more aversive and distressful than lower frequency cries. Besides, previous studies have speculated that in children with Autism Spectrum Disorder (ASD) higher f0 may account for evoking mental states of uneasiness in the caregiver. Moreover no evidence on developmental…

  1. The Fundamental Lifestyle of a University Community: A Case Study of Higher Education in a Malaysian Institution

    ERIC Educational Resources Information Center

    Abdullah, Melissa Ng Lee Yen; Mey, See Ching

    2012-01-01

    This study identified the fundamental lifestyles adopted by a university community in Malaysia. Rapid growth and expansion of higher education in Malaysia is inevitable as the country moves from a production-based economy to one that is innovative and knowledge-based, requiring the development of a highly skilled and knowledgeable workforce.…

  2. Fundamental studies on electrochemical production of dendrite-free aluminum and titanium-aluminum alloys

    NASA Astrophysics Data System (ADS)

    Pradhan, Debabrata

    -Al alloys were determined. The Ti-Al alloys containing about 13-27 atom % Ti were produced using both electrolytes. The current efficiency of AlCl3-BMIC was varies between 79-87%. But lower current efficiency (25-38%) was obtained for AlCl3-BMIC-TiCl4 electrolytes due to the formation of TiCl3 passive layer on the electrodes. To increase the productivity, constant current method (160-210 A/m2) was implemented. This fundamental study on low temperature production of dendrite-free aluminum and Al-Ti alloys is not only efficient but also opens a novel route in aluminum and titanium process metallurgy.

  3. Fundamental studies of solution and gaseous reactions at transition metal surfaces

    NASA Astrophysics Data System (ADS)

    Qiu, Siping

    Redox reactions at metal surfaces have many important applications. For example, they are used to remove contaminants from solution for environmental remediation, and are also used for the growth of dielectric thin films. This dissertation investigates surface chemical reactions at the liquid-solid and vapor-solid interfaces. Chemical reactions at the solid-liquid interface were investigated in an effort to bridge the gap between conventional bulk solution chemical studies and UHV gas phase surface reactions studies. Such reactions have not been studied extensively at the fundamental level due to the inherent complexity of the systems. Saline solutions containing selenate, chromate and uranyl contaminant ions were reacted with Fe and Fe oxide surfaces. Scanning tunneling microscopy (STM) images collected in situ were used to monitor the changes in surface morphology during reaction. X-ray photoelectron spectroscopy (XPS) was used to identify the surface products following reaction. The foil surfaces become smoother due to both etching of the substrate and the deposition of material. Selenium and chromium are deposited onto the surface in a partially reduced form, while uranium is deposited without reduction. The amount of material deposited is dependent on the presence of dissolved gases, such as O2 and CO2, in the solution. Gaseous SeF6 was reacted with atomically clean iron and iron oxide surfaces in vacuum in order to model the reduction of selenate. The resulting surfaces were examined with XPS. It was found that SeF6 dissociatively chemisorbs onto iron, i.e., the selenium is completely reduced. In the reaction with a clean Fe surface, a thin film of FeF2 is formed. Surface oxide inhibits the adsorption of SeF6. The growth of the FeF2 film initially follows MottCabrera kinetics, but then abruptly stops. It is suggested that the shutdown is due to the inability of electrons from the substrate to transport through the film when it becomes too thick. These

  4. Experimental Study of Additives on Viscosity biodiesel at Low Temperature

    NASA Astrophysics Data System (ADS)

    Fajar, Berkah; Sukarno

    2015-09-01

    An experimental investigation was performed to find out the viscosity of additive and biodiesel fuel mixture in the temperature range from 283 K to 318 K. Solutions to reduce the viscosity of biodiesel is to add the biodiesel with some additive. The viscosity was measured using a Brookfield Rheometer DV-II. The additives were the generic additive (Diethyl Ether/DDE) and the commercial additive Viscoplex 10-330 CFI. Each biodiesel blends had a concentration of the mixture: 0.0; 0.25; 0.5; 0.75; 1.0; and 1.25% vol. Temperature of biodiesel was controlled from 40°C to 0°C. The viscosity of biodiesel and additive mixture at a constant temperature can be approximated by a polynomial equation and at a constant concentration by exponential equation. The optimum mixture is at 0.75% for diethyl ether and 0.5% for viscoplex.

  5. Fundamental studies of coal liquefaction. Quarterly report No. 8, July 1, 1993--October 1, 1993

    SciTech Connect

    Ross, D.S.

    1993-10-14

    In the last report the effects of water, tetralin, and argon were discussed as media during the heating of Illinois No. 6 coal. In studies in which the temperature was ramped from ambient to 460{degrees}C at 30{degrees}C/min particles were observed to shrink in the case of both water and tetralin, and first swell and then collapse back to particles with their starting shapes in the case of argon. The result with tetralin was expected, but that for water was not. Similarly, the results in argon were not in accord with some models of coal pyrolysis which suggest that coals fully liquefy when heated (Solomon, et al.). The work described here includes discussion of additional work with Illinois No. 6 coal with argon and water, and new work with n-undecane as medium.

  6. Marketing fundamentals.

    PubMed

    Redmond, W H

    2001-01-01

    This chapter outlines current marketing practice from a managerial perspective. The role of marketing within an organization is discussed in relation to efficiency and adaptation to changing environments. Fundamental terms and concepts are presented in an applied context. The implementation of marketing plans is organized around the four P's of marketing: product (or service), promotion (including advertising), place of delivery, and pricing. These are the tools with which marketers seek to better serve their clients and form the basis for competing with other organizations. Basic concepts of strategic relationship management are outlined. Lastly, alternate viewpoints on the role of advertising in healthcare markets are examined. PMID:11401791

  7. Additive Manufacturing in Production: A Study Case Applying Technical Requirements

    NASA Astrophysics Data System (ADS)

    Ituarte, Iñigo Flores; Coatanea, Eric; Salmi, Mika; Tuomi, Jukka; Partanen, Jouni

    Additive manufacturing (AM) is expanding the manufacturing capabilities. However, quality of AM produced parts is dependent on a number of machine, geometry and process parameters. The variability of these parameters affects the manufacturing drastically and therefore standardized processes and harmonized methodologies need to be developed to characterize the technology for end use applications and enable the technology for manufacturing. This research proposes a composite methodology integrating Taguchi Design of Experiments, multi-objective optimization and statistical process control, to optimize the manufacturing process and fulfil multiple requirements imposed to an arbitrary geometry. The proposed methodology aims to characterize AM technology depending upon manufacturing process variables as well as to perform a comparative assessment of three AM technologies (Selective Laser Sintering, Laser Stereolithography and Polyjet). Results indicate that only one machine, laser-based Stereolithography, was feasible to fulfil simultaneously macro and micro level geometrical requirements but mechanical properties were not at required level. Future research will study a single AM system at the time to characterize AM machine technical capabilities and stimulate pre-normative initiatives of the technology for end use applications.

  8. ULTRASONIC STUDIES OF THE FUNDAMENTAL MECHANISMS OF RECRYSTALLIZATION AND SINTERING OF METALS

    SciTech Connect

    TURNER, JOSEPH A.

    2005-11-30

    The purpose of this project was to develop a fundamental understanding of the interaction of an ultrasonic wave with complex media, with specific emphases on recrystallization and sintering of metals. A combined analytical, numerical, and experimental research program was implemented. Theoretical models of elastic wave propagation through these complex materials were developed using stochastic wave field techniques. The numerical simulations focused on finite element wave propagation solutions through complex media. The experimental efforts were focused on corroboration of the models developed and on the development of new experimental techniques. The analytical and numerical research allows the experimental results to be interpreted quantitatively.

  9. Fundamental study of ash formation and deposition: Effect of reducing stoichiometry

    SciTech Connect

    Helble, J.J.; Bool, L.E.; Kang, S.G.

    1995-11-01

    This project is designed to examine the effects of combustion stoichiometry on the fundamental aspects of ash formation and ash deposit initiation. Emphasis is being placed on reducing stoichiometries associated with low-NOx combustion, although a range of oxidant/fuel ratios are being considered. Previous work has demonstrated that ash formation depends strongly upon coal mineralogy, including mineral type, size, amount, and the presence of organically associated inorganic species. Combustion temperature and the oxidation state of iron also play a significant role. As these latter items will vary with changes in stoichiometry, research to determine the net effect on deposition is required.

  10. Nanosecond Pulsed Discharge in Water without Bubbles: A Fundamental Study of Initiation, Propagation and Plasma Characteristics

    NASA Astrophysics Data System (ADS)

    Seepersad, Yohan

    The state of plasma is widely known as a gas-phase phenomenon, but plasma in liquids have also received significant attention over the last century. Generating plasma in liquids however is theoretically challenging, and this problem is often overcome via liquid-gas phase transition preceding the actual plasma formation. In this sense, plasma forms in gas bubbles in the liquid. Recent work at the Drexel Plasma Institute has shown that nanosecond pulsed electric fields can initiate plasma in liquids without any initial cavitation phase, at voltages below theoretical direct-ionization thresholds. This unique regime is poorly understood and does not fit into any current descriptive mechanisms. As with all new phenomena, a complete fundamental description is paramount to understanding its usefulness to practical applications. The primary goals of this research were to qualitatively and quantitatively understand the phenomenon of nanosecond pulsed discharge in liquids as a means to characterizing properties that may open up niche application possibilities. Analysis of the plasma was based on experimental results from non-invasive, sub-nanosecond time-resolved optical diagnostics, including direct imaging, transmission imaging (Schlieren and shadow), and optical emission spectroscopy. The physical characteristics of the plasma were studied as a function of variations in the electric field amplitude and polarity, liquid permittivity, and pulse duration. It was found that the plasma size and emission intensity was dependent on the permittivity of the liquid, as well as the voltage polarity, and the structure and dynamics were explained by a 'cold-lightning' mechanism. The under-breakdown dynamics at the liquid-electrode interface were investigated by transmission imaging to provide evidence for a novel mechanism for initiation based on the electrostriction. This mechanism was proposed by collaborators on the project and developed alongside the experimental work in this

  11. Quantitative studies of the optical and UV spectra of Galactic early B supergiants. I. Fundamental parameters

    NASA Astrophysics Data System (ADS)

    Searle, S. C.; Prinja, R. K.; Massa, D.; Ryans, R.

    2008-04-01

    Aims: We undertake an optical and ultraviolet spectroscopic analysis of a sample of 20 Galactic B0-B5 supergiants of luminosity classes Ia, Ib, Iab, and II. Fundamental stellar parameters are obtained from optical diagnostics and a critical comparison of the model predictions to observed UV spectral features is made. Methods: Fundamental parameters (e.g., {T_eff}, {log L*}, mass-loss rates and CNO abundances) are derived for individual stars using CMFGEN, a nLTE, line-blanketed model atmosphere code. The impact of these newly derived parameters on the Galactic B supergiant {T_eff} scale, mass discrepancy, and wind-momentum luminosity relation is examined. Results: The B supergiant temperature scale derived here shows a reduction of about 1000-3000 K compared to previous results using unblanketed codes. Mass-loss rate estimates are in good agreement with predicted theoretical values, and all of the 20 B0-B5 supergiants analysed show evidence of CNO processing. A mass discrepancy still exists between spectroscopic and evolutionary masses, with the largest discrepancy occurring at {log (L/L⊙}) 5.4. The observed WLR values calculated for B0-B0.7 supergiants are higher than predicted values, whereas the reverse is true for B1-B5 supergiants. This means that the discrepancy between observed and theoretical values cannot be resolved by adopting clumped (i.e., lower) mass-loss rates as for O stars. The most surprising result is that, although CMFGEN succeeds in reproducing the optical stellar spectrum accurately, it fails to precisely reproduce key UV diagnostics, such as the N V and C IV P Cygni profiles. This problem arises because the models are not ionised enough and fail to reproduce the full extent of the observed absorption trough of the P Cygni profiles. Conclusions: Newly-derived fundamental parameters for early B supergiants are in good agreement with similar work in the field. The most significant discovery, however, is the failure of CMFGEN to predict the

  12. Fundamental movement skills and physical fitness as predictors of physical activity: A 6-year follow-up study.

    PubMed

    Jaakkola, T; Yli-Piipari, S; Huotari, P; Watt, A; Liukkonen, J

    2016-01-01

    The purpose of this study was to examine the extent to which fundamental movement skills and physical fitness scores assessed in early adolescence predict self-reported physical activity assessed 6 years later. The sample comprised 333 (200 girls, 133 boys; M age = 12.41) students. The effects of previous physical activity, sex, and body mass index (BMI) were controlled in the main analyses. Adolescents' fundamental movement skills, physical fitness, self-report physical activity, and BMI were collected at baseline, and their self-report energy expenditure (metabolic equivalents: METs) and intensity of physical activity were collected using the International Physical Activity Questionnaire 6 years later. Results showed that fundamental movement skills predicted METs, light, moderate, and vigorous intensity physical activity levels, whereas fitness predicted METs, moderate, and vigorous physical activity levels. Hierarchical regression analyses also showed that after controlling for previous levels of physical activity, sex, and BMI, the size of the effect of fundamental movement skills and physical fitness on energy expenditure and physical activity intensity was moderate (R(2) change between 0.06 and 0.15), with the effect being stronger for high intensity physical activity. PMID:25644386

  13. Radioactive ion beam transportation for the fundamental symmetry study with laser-trapped atoms.

    PubMed

    Arikawa, Hiroshi; Ando, S; Aoki, T; Ezure, S; Harada, K; Hayamizu, T; Inoue, T; Ishikawa, T; Itoh, M; Kawamura, H; Kato, K; Kato, T; Uchiyama, A; Aoki, T; Furukawa, T; Hatakeyama, A; Hatanaka, K; Imai, K; Murakami, T; Nataraj, H S; Sato, T; Shimizu, Y; Wakasa, T; Yoshida, H P; Sakemi, Y

    2014-02-01

    The search for the violation of the fundamental symmetry in a radioactive atom is the promising candidate for precision tests of the standard model and its possible extensions. The subtle signal arising from the symmetry violation is enhanced in heavy atoms, such as a francium (Fr). To realize high precision measurements, a large amount of radioactive isotopes is required. The Fr is produced via a nuclear fusion reaction using a melted gold target with a (18)O primary beam at Cyclotron and Radioisotope Center, Tohoku University. The maximum extraction efficiency of the Fr ion was achieved at approximately 35%. The beam line consists of an electrostatic deflector, three electrostatic quadrupole triplets to the measurement area at 10 m away from the reaction point, and several beam diagnosis systems. We optimized parameters of the beam line. PMID:24593466

  14. Radioactive ion beam transportation for the fundamental symmetry study with laser-trapped atoms

    NASA Astrophysics Data System (ADS)

    Arikawa, Hiroshi; Ando, S.; Aoki, T.; Ezure, S.; Harada, K.; Hayamizu, T.; Inoue, T.; Ishikawa, T.; Itoh, M.; Kawamura, H.; Kato, K.; Kato, T.; Uchiyama, A.; Aoki, T.; Furukawa, T.; Hatakeyama, A.; Hatanaka, K.; Imai, K.; Murakami, T.; Nataraj, H. S.; Sato, T.; Shimizu, Y.; Wakasa, T.; Yoshida, H. P.; Sakemi, Y.

    2014-02-01

    The search for the violation of the fundamental symmetry in a radioactive atom is the promising candidate for precision tests of the standard model and its possible extensions. The subtle signal arising from the symmetry violation is enhanced in heavy atoms, such as a francium (Fr). To realize high precision measurements, a large amount of radioactive isotopes is required. The Fr is produced via a nuclear fusion reaction using a melted gold target with a 18O primary beam at Cyclotron and Radioisotope Center, Tohoku University. The maximum extraction efficiency of the Fr ion was achieved at approximately 35%. The beam line consists of an electrostatic deflector, three electrostatic quadrupole triplets to the measurement area at 10 m away from the reaction point, and several beam diagnosis systems. We optimized parameters of the beam line.

  15. Radioactive ion beam transportation for the fundamental symmetry study with laser-trapped atoms.

    PubMed

    Arikawa, Hiroshi; Ando, S; Aoki, T; Ezure, S; Harada, K; Hayamizu, T; Inoue, T; Ishikawa, T; Itoh, M; Kawamura, H; Kato, K; Kato, T; Uchiyama, A; Aoki, T; Furukawa, T; Hatakeyama, A; Hatanaka, K; Imai, K; Murakami, T; Nataraj, H S; Sato, T; Shimizu, Y; Wakasa, T; Yoshida, H P; Sakemi, Y

    2014-02-01

    The search for the violation of the fundamental symmetry in a radioactive atom is the promising candidate for precision tests of the standard model and its possible extensions. The subtle signal arising from the symmetry violation is enhanced in heavy atoms, such as a francium (Fr). To realize high precision measurements, a large amount of radioactive isotopes is required. The Fr is produced via a nuclear fusion reaction using a melted gold target with a (18)O primary beam at Cyclotron and Radioisotope Center, Tohoku University. The maximum extraction efficiency of the Fr ion was achieved at approximately 35%. The beam line consists of an electrostatic deflector, three electrostatic quadrupole triplets to the measurement area at 10 m away from the reaction point, and several beam diagnosis systems. We optimized parameters of the beam line.

  16. Radioactive ion beam transportation for the fundamental symmetry study with laser-trapped atoms

    SciTech Connect

    Arikawa, Hiroshi Ando, S.; Aoki, T.; Ezure, S.; Harada, K.; Hayamizu, T.; Inoue, T.; Ishikawa, T.; Itoh, M.; Kawamura, H.; Kato, K.; Kato, T.; Uchiyama, A.; Sakemi, Y.; Aoki, T.; Furukawa, T.; Hatakeyama, A.; Hatanaka, K.; Yoshida, H. P.; Imai, K.; and others

    2014-02-15

    The search for the violation of the fundamental symmetry in a radioactive atom is the promising candidate for precision tests of the standard model and its possible extensions. The subtle signal arising from the symmetry violation is enhanced in heavy atoms, such as a francium (Fr). To realize high precision measurements, a large amount of radioactive isotopes is required. The Fr is produced via a nuclear fusion reaction using a melted gold target with a {sup 18}O primary beam at Cyclotron and Radioisotope Center, Tohoku University. The maximum extraction efficiency of the Fr ion was achieved at approximately 35%. The beam line consists of an electrostatic deflector, three electrostatic quadrupole triplets to the measurement area at 10 m away from the reaction point, and several beam diagnosis systems. We optimized parameters of the beam line.

  17. Studies of collision-induced emission in the fundamental vibration-rotation band of H2

    NASA Astrophysics Data System (ADS)

    Caledonia, G. E.; Krech, R. H.; Wilkerson, T.; Taylor, R. L.; Birnbaum, G.

    Measurements are presented of the collision induced emission (CIE) from the fundamental vibration-rotation band of H2 taken over the temperature range of 900-3000 K. The spectral shape and strength of this IR band centered about 2.4 microns has been measured behind reflected shocks in mixtures of H2/Ar. The observed radiation at elevated temperatures is found to be dominantly in the Q branch. The results, compared with theory, show that radiation at elevated temperatures is primarily the result of an induced dipole moment in H2 induced by the overlap between the H2 and Ar electron clouds during collision. The strength of this interaction has been evaluated by an analysis of the measured temperature dependence of the absolute bandstrengths.

  18. Fundamental studies of bulk flow of fine coal. Quarterly report, October 1-December 31, 1985

    SciTech Connect

    Hogg, R.; Luckie, P.T.

    1986-04-01

    Research during this period has been concentrated in the areas of evaluation of test procedures and the analysis of powder flow in real systems. A comparative study of the use of the Jenike (translational) and Peschl (rotational) shear cells for the measurement of powder flow properties is in progress. The results to date indicate that both systems given reproducible, self-consistent data but that there can be significant differences between the two kinds of measurements. Semi-quantitative explanations, based on equipment limitations, etc., have been suggested to account for the discrepancies. Because of the importance of these measurements in the design of bulk materials handling and storage equipment, we believe that resolution of these apparent anomalies should be a critical aspect of our research effort. The application of powder flow criteria to real systems depends on the analysis of stresses in converging channels. We are using a modified stress analysis which can allow for additional variations in material properties with consolidation in an attempt to assess the value of the standard flowability criteria in such systems. 14 refs., 2 figs.

  19. Exhaust Gas Recirculation Cooler Fouling in Diesel Applications: Fundamental Studies Deposit Properties and Microstructure

    SciTech Connect

    Storey, John Morse; Sluder, Scott; Lance, Michael J; Styles, Dan; Simko, Steve

    2013-01-01

    This paper reports on the results of experimental efforts aimed at improving the understanding of the mechanisms and conditions at play in the fouling of EGR coolers. An experimental apparatus was constructed to utilize simplified surrogate heat exchanger tubes in lieu of full-size heat exchangers. The use of these surrogate tubes allowed removal of the tubes after exposure to engine exhaust for study of the deposit layer and its properties. The exhaust used for fouling the surrogate tubes was produced using a modern medium-duty diesel engine fueled with both ultra-low sulfur diesel and biodiesel blends. At long exposure times, no significant difference in the fouling rate was observed between fuel types and HC levels. Surface coatings for the tubes were also evaluated to determine their impact on deposit growth. No surface treatment or coating produced a reduction in the fouling rate or any evidence of deposit removal. In addition, microstructural analysis of the fouling layers was performed using optical and electron microscopy in order to better understand the deposition mechanism. The experimental results are consistent with thermophoretic deposition for deposit formation, and van der Waals attraction between the deposit surface and exhaust-borne particulate.

  20. Fundamental studies of grain boundary passivation in polycrystalline silicon with application to improved photovoltaic devices

    NASA Astrophysics Data System (ADS)

    Seager, C. H.; Ginley, D. S.

    1980-02-01

    Several aspects of the electrical properties of silicon grain boundaries were studied. The temperature dependence of the zero bias conductance and capacitance of single boundaries was measured and shown to be in good agreement with a simple double depletion layer/thermal emission model developed to predict the transport properties of such structures. In addition, it was shown that deconvolution of the I-V properties of some boundaries yields effective one electron densities of trapping states which are in good agreement with estimates obtained by low temperature electron emission measurements. Experiments were also performed which indicate that diffusion of atomic hydrogen into silicon grain boundaries greatly reduces this density of trapping states. In properly prepared, large grained polycrystalline samples, all measurable traces of grain boundary potential barriers can be removed to substantial penetration depths after several hours exposure to a hydrogen plasma at elevated temperatures. Initial experiments on prototype polysilicon solar cells have shown that this passivation process can improve AM1 efficiencies.

  1. Fundamental study of optical threshold layer approach towards double exposure lithography

    NASA Astrophysics Data System (ADS)

    Gu, Xinyu; Berro, Adam J.; Cho, Younjin; Jen, Kane; Lee, Saul; Ngai, Tomoki; Ogata, Toshiyuki; Durand, William J.; Sundaresan, Arunkumar; Lancaster, Jeffrey R.; Jockusch, Steffen; Zimmerman, Paul; Turro, Nicholas J.; Willson, C. G.

    2009-03-01

    193 immersion lithography has reached its maximal achievable resolution. There are mainly two lithographic strategies that will enable continued increase in resolution. Those are being pursued in parallel. The first is extreme ultraviolet (EUV) lithography and the second is double patterning (exposure) lithography. EUV lithography is counted on to be available in 2013 time frame for 22 nm node. Unfortunately, this technology has suffered several delays due to fundamental problems with source power, mask infrastructure, metrology and overall reliability. The implementation of EUV lithography in the next five years is unlikely due to economic factors. Double patterning lithography (DPL) is a technology that has been implemented by the industry and has already shown the proof of concept for the 22nm node. This technique while expensive is the only current path forward for scaling with no fundamental showstoppers for the 32nm and 22nm nodes. Double exposure lithography (DEL) is being proposed as a cost mitigating approach to advanced lithography. Compared to DPL, DEL offers advantages in overlay and process time, thus reducing the cost-of-ownership (CoO). However, DEL requires new materials that have a non-linear photoresponse. So far, several approaches were proposed for double exposure lithography, from which Optical Threshold Layer (OTL) was found to give the best lithography performance according to the results of the simulation. This paper details the principle of the OTL approach. A photochromic polymer was designed and synthesized. The feasibility of the material for application of DEL was explored by a series of evaluations.

  2. Health studies indicate MTBE is safe gasoline additive

    SciTech Connect

    Anderson, E.V.

    1993-09-01

    Implementation of the oxygenated fuels program by EPA in 39 metropolitan areas, including Fairbanks and Anchorage, Alaska, in the winter of 1992, encountered some unexpected difficulties. Complaints of headaches, dizziness, nausea, and irritated eyes started in Fairbanks, jumped to Anchorage, and popped up in various locations in the lower 48 states. The suspected culprit behind these complaints was the main additive for oxygenation of gasoline is methyl tert-butyl ether (MTBE). A test program, hastily organized in response to these complaints, has indicated that MTBE is a safe gasoline additive. However, official certification of the safety of MTBE is still awaited.

  3. Fundamental Study on Temperature Dependence of Deposition Rate of Silicic Acid - 13270

    SciTech Connect

    Shinmura, Hayata; Niibori, Yuichi; Mimura, Hitoshi

    2013-07-01

    The dynamic behavior of the silicic acid is one of the key factors to estimate the condition of the repository system after the backfill. This study experimentally examined the temperature dependence of dynamic behavior of supersaturated silicic acid in the co-presence of solid phase, considering Na ions around the repository, and evaluated the deposition rate constant, k, of silicic acid by using the first-order reaction equation considering the specific surface area. The values of k were in the range of 1.0x10{sup -11} to 1.0x10{sup -9} m/s in the temperature range of 288 K to 323 K. The deposition rate became larger with increments of temperature under the Na ion free condition. Besides, in the case of Na ions 0.6 M, colloidal silicic acid decreased dramatically at a certain time. This means that the diameter of the colloidal silicic acid became larger than the pore size of filter (0.45 μm) due to bridging of colloidal silicic acid. Furthermore, this study estimated the range of altering area and the aperture of flow-path in various value of k corresponding to temperature by using advection-dispersion model. The concentration in the flow-path became lower with increments of temperature, and when the value of k is larger than 1.0x10{sup -11} m/s, the deposition range of supersaturated silicic acid was estimated to be less than 20 m around the repository. In addition, the deposition of supersaturated silicic acid led the decrement of flow-path aperture, which was remarkable under the condition of relatively high temperature. Such a clogging in flow paths is expected as a retardation effect of radionuclides. (authors)

  4. Fundamental studies of the chemical vapor deposition of diamond. Final technical report, April 1, 1988--December 31, 1994

    SciTech Connect

    Nix, W.D.

    1995-05-01

    We submit here a final technical report for the research program entitled: Fundamental Studies of the Chemical Vapor Deposition of Diamond, DOE Grant No. DE-FG05-88ER45345-M006. This research program was initiated in 1988 under the direction of the late Professor David A. Stevenson and was renewed in 1992. Unfortunately, at the end of 1992, just as the last phase of this work was getting underway, Professor Stevenson learned that he had developed mesothelioma, a form of cancer based on asbestos. Professor Stevenson died from that disease in February of 1994. Professor William D. Nix, the Chairman of the Materials Science department at Stanford was named the Principal Investigator. Professor Nix has assembled this final technical report. Much of the work of this grant was conducted by Mr. Paul Dennig, a graduate student who will receive his Ph.D. degree from Stanford in a few months. His research findings are described in the chapters of this report and in the papers published over the past few years. The main discovery of this work was that surface topology plays a crucial role in the nucleation of diamond on silicon. Dennig and his collaborators demonstrated this by showing that diamond nucleates preferentially at the tips of asperities on a silicon surface rather than in the re-entrant comers at the base of such asperities. Some of the possible reasons for this effect are described in this report. The published papers listed on the next page of this report also describe this research. Interested persons can obtain copies of these papers from Professor Nix at Stanford. A full account of all of the research results obtained in this work is given in the regular chapters that follow this brief introduction. In addition, interested readers will want to consult Mr. Dennig`s Ph.D. dissertation when it is made available later this year.

  5. Exploiting the Temperature Dependence of Magnetic Susceptibility to Control Convection in Fundamental Studies of Solidification Phenomena

    NASA Technical Reports Server (NTRS)

    Seybert, C. D.; Evans, J. W.; Leslie, Fred; Jones, W. K., Jr.

    2000-01-01

    It is well known that convection is a dominant mass transport mechanism when materials are solidified on Earth's surface. This convection is caused by gradients in density (and therefore gravitational force) that are brought about by gradients in temperature, composition or both. Diffusion of solute is therefore dwarfed by convection and the study of fundamental parameters, such as dendrite tip shape and growth velocity in the absence of convection is nearly impossible. Significant experimental work has therefore been carried out in orbiting laboratories with the intent of minimizing convection by minimizing gravity. One of the best known experiments of this kind is the Isothermal Dendritic Growth Experiment (IDGE), supported by NASA. Naturally such experiments are costly and one objective of the present investigation is to develop an experimental method whereby convection can be- halted, in solidification and other experiments, on the surface. A second objective is to use the method to minimize convection resulting from the residual accelerations suffered by experiments in microgravity. The method to be used to minimize convection relies on the dependence of the magnetic susceptibility of a fluid on temperature or composition (whichever is driving convection). All materials experience a force when placed in a magnetic field gradient. The direction and magnitude of that force depend on the magnetic susceptibility of the material. Consequently the force will vary if the susceptibility varies with temperature or composition. With a magnetic field gradient in the right direction (typically upward) and of the right magnitude, this variation in the magnetic force can be made to exactly cancel the variation in the gravitational force. Expressed another way, normal buoyancy is exactly countered by a "magnetic buoyancy". To demonstrate the principle, a solution of MnC12 in water has been used. First the variation of the susceptibility of this paramagnetic solution with

  6. Fundamental studies on ultrasonic cavitation-assisted molten metal processing of A356-nanocomposites

    NASA Astrophysics Data System (ADS)

    Liu, Xiaoda

    The usage of lightweight high-performance components is expected to increase significantly as automotive, military and aerospace industries are required to improve the energy efficiency and the performance of their products. A356, which is much lighter than steel, is an attractive replacement material. Therefore, it is of great interest to enhance its properties. There is strong evidence that the microstructure and mechanical properties can be considerably improved if nanoparticles are used as reinforcement to form metal-matrix-nano-composite (MMNC). Several recent studies revealed that ultrasonic vibration is highly efficient in dispersing nanoparticles into the melt and producing MMNC. In this thesis, a detailed analysis of the microstructure and mechanical properties is provided for an A356 alloy enhanced with Al2O 3 and SiC nanoparticles via ultrasonic processing. Each type of the nanoparticles was inserted into the A356 molten metal and dispersed by ultrasonic cavitation and acoustic streaming technology (UST) to avoid agglomeration or coalescence. The results showed that microstructures were greatly refined and with the addition of nanoparticles, tensile strength, yield strength and elongation increased significantly. SEM and EDS analyses were also performed to analyze the dispersion of nanoparticles in the A356 matrix. Since the ultrasonic energy is concentrated in a small region under the ultrasonic probe, it is difficult to ensure proper cavitation and acoustic streaming for efficient dispersion of the nanoparticles (especially in larger UST systems) without to determine the suitable ultrasonic parameters via modeling and simulation. Accordingly, another goal of this thesis was to develop well-controlled UST experiments that can be used in the development and validation of a recently developed UST modeling and simulation tool.

  7. Fundamental movement skills and physical activity among children living in low-income communities: a cross-sectional study

    PubMed Central

    2014-01-01

    Background Although previous studies have demonstrated that children with high levels of fundamental movement skill competency are more active throughout the day, little is known regarding children’s fundamental movement skill competency and their physical activity during key time periods of the school day (i.e., lunchtime, recess and after-school). The purpose of this study was to examine the associations between fundamental movement skill competency and objectively measured moderate-to-vigorous physical activity (MVPA) throughout the school day among children attending primary schools in low-income communities. Methods Eight primary schools from low-income communities and 460 children (8.5 ± 0.6 years, 54% girls) were involved in the study. Children’s fundamental movement skill competency (TGMD-2; 6 locomotor and 6 object-control skills), objectively measured physical activity (ActiGraph GT3X and GT3X + accelerometers), height, weight and demographics were assessed. Multilevel linear mixed models were used to assess the cross-sectional associations between fundamental movement skills and MVPA. Results After adjusting for age, sex, BMI and socio-economic status, locomotor skill competency was positively associated with total (P = 0.002, r = 0.15) and after-school (P = 0.014, r = 0.13) MVPA. Object-control skill competency was positively associated with total (P < 0.001, r = 0.20), lunchtime (P = 0.03, r = 0.10), recess (P = 0.006, r = 0.11) and after-school (P = 0.022, r = 0.13) MVPA. Conclusions Object-control skill competency appears to be a better predictor of children’s MVPA during school-based physical activity opportunities than locomotor skill competency. Improving fundamental movement skill competency, particularly object-control skills, may contribute to increased levels of children’s MVPA throughout the day. Trial registration Australian New Zealand Clinical Trials Registry No: ACTRN

  8. Impact of Four Nonclinical Speaking Environments on a Child's Fundamental Frequency and Voice Level: A Preliminary Case Study

    ERIC Educational Resources Information Center

    Hunter, Eric J.; Halpern, Angela E.; Spielman, Jennifer L.

    2012-01-01

    Purpose: The aim of this study was to investigate how a child's fundamental frequency (F0) and estimated voice level (dB SPL) change in distinct speaking environments. Method: A child age 5;7 (years;months) wore a National Center for Voice and Speech voice dosimeter for 4 days. The 2 parameters measured were F0 and dB SPL. During analysis, the F0…

  9. Kinetic study of additions of dialkylmagnesium compounds to a cycloprene

    SciTech Connect

    Watkins, E.K.; Richey, H.G. Jr.

    1992-11-01

    Reaction of Et{sub 2}Mg and spiro[2.4]hept-1-ene (1) in tetahydrofuran followed by hydrolysis furnishes mainly 1-ethylspiro[2.4]heptane (3); when hydrolysis is with D{sub 2}O, {ge}98% of this (Z)-1-ethylspirol[2.4]heptane-2-d (4). Some metalation of 1 and formation of higher molecular weight products incorporating two or three molecules of 1 also take place. Formation of 3 is first order in 1 and in Et{sub 2}Mg, and at 35.47{degrees}C the rate constant is 1.2 x 10{sup -5} L M{sup -1}s{sup -1}. Under the same conditions, the rate of addition (1.5 x 10{sup -5} L M{sup -1}{sub s}{sup -1}). Under the same conditions, the rate of addition (1.5 x 10{sup -5} L mol{sup -1} {sub s}{sup -1}) of the Grignard reagent prepared from EtBr is similar. Reactions of 1 with Me{sub 2}Mg, I-Pr{sub 2}Mg, and t-Bu{sub 2}Mg. Added Fe(acac){sub 3} increases the rate of formation of 3 from reactions of 1 with either Et{sub 2}Mg or the Grignard reagent prepared from EtBr, but additional products also are formed. 55 refs., 2 tabs.

  10. Studies of fundamental properties of rutherfordium (Element 104) using organic complexing agents

    SciTech Connect

    Czerwinski, K.R.

    1992-04-01

    Chemical properties of rutherfordium (Rf) have been investigated with the organic ligands triisooctylamine (TIOA), tributylphosphate (TBP), and thenoyltrifluoroacetone (TTA). The TIOA studies showed that Rf behaves differently than Th and Eu and most similarly to Zr, only Zr and Rf extract from 12 M HCI. This result is further evidence that Rf is a Group 4 element. Studies with TBP showed that Rf chemical behavior differed from the other Group 4 elements. The extraction by TBP at different chloride concentrations showed that Rf at times behaves more like Pu{sup 4+} than Zr or Hf. At high chloride concentrations, Rf and Pu extraction decreased. Under the same conditions, Zr, Hf and Th extraction increased. In addition, Rf extraction by TBP was affected by hydrogen ion concentration, while Zr and Hf extraction was not. TTA extractions were used to determine the K{sub eq}, K{sub hyd}, and the ionic radius of Rf. The of K{sub eq} for Rf with TTA was calculated to be 3.18 {plus minus} 0.90. The first four log K{sub hyd's} for Rf are calculated to be {minus}2.6 {plus minus} 0.7, {minus}5.9 {plus minus} 1.7, {minus}10.2 {plus minus} 2.9, and {minus}14.5 {plus minus} 4.1. These hydrolysis constants indicate that Rf will not hydrolyze at conditions under which Zr, Hf, and Pu will. Calculations of the ionic radius were made with the log K{sub eq} for Rf derived with TTA. The ionic radius of Rf was calculated to be 91 {plus minus} 4 pm for the 6-coordinate species and 102 {plus minus} 4 pm for the 8-coordinate species. A search for the isotope {sup 263}Rf was conducted using TTA chemistry. In 300 experiments, seven SF events and no alpha events were observed in the Rf chemical fraction. The observed SF events attributed to {sup 263}Rf and had a half-life of 500 {plus minus}{sub 200}{sup 300} seconds and a production cross section of 140 {plus minus} 50 pb.

  11. Studies of fundamental properties of rutherfordium (Element 104) using organic complexing agents

    SciTech Connect

    Czerwinski, K.R.

    1992-04-01

    Chemical properties of rutherfordium (Rf) have been investigated with the organic ligands triisooctylamine (TIOA), tributylphosphate (TBP), and thenoyltrifluoroacetone (TTA). The TIOA studies showed that Rf behaves differently than Th and Eu and most similarly to Zr, only Zr and Rf extract from 12 M HCI. This result is further evidence that Rf is a Group 4 element. Studies with TBP showed that Rf chemical behavior differed from the other Group 4 elements. The extraction by TBP at different chloride concentrations showed that Rf at times behaves more like Pu{sup 4+} than Zr or Hf. At high chloride concentrations, Rf and Pu extraction decreased. Under the same conditions, Zr, Hf and Th extraction increased. In addition, Rf extraction by TBP was affected by hydrogen ion concentration, while Zr and Hf extraction was not. TTA extractions were used to determine the K{sub eq}, K{sub hyd}, and the ionic radius of Rf. The of K{sub eq} for Rf with TTA was calculated to be 3.18 {plus_minus} 0.90. The first four log K{sub hyd`s} for Rf are calculated to be {minus}2.6 {plus_minus} 0.7, {minus}5.9 {plus_minus} 1.7, {minus}10.2 {plus_minus} 2.9, and {minus}14.5 {plus_minus} 4.1. These hydrolysis constants indicate that Rf will not hydrolyze at conditions under which Zr, Hf, and Pu will. Calculations of the ionic radius were made with the log K{sub eq} for Rf derived with TTA. The ionic radius of Rf was calculated to be 91 {plus_minus} 4 pm for the 6-coordinate species and 102 {plus_minus} 4 pm for the 8-coordinate species. A search for the isotope {sup 263}Rf was conducted using TTA chemistry. In 300 experiments, seven SF events and no alpha events were observed in the Rf chemical fraction. The observed SF events attributed to {sup 263}Rf and had a half-life of 500 {plus_minus}{sub 200}{sup 300} seconds and a production cross section of 140 {plus_minus} 50 pb.

  12. Healthcare fundamentals.

    PubMed

    Kauk, Justin; Hill, Austin D; Althausen, Peter L

    2014-07-01

    In order for a trauma surgeon to have an intelligent discussion with hospital administrators, healthcare plans, policymakers, or any other physicians, a basic understanding of the fundamentals of healthcare is paramount. It is truly shocking how many surgeons are unable to describe the difference between Medicare and Medicaid or describe how hospitals and physicians get paid. These topics may seem burdensome but they are vital to all business decision making in the healthcare field. The following chapter provides further insight about what we call "the basics" of providing medical care today. Most of the topics presented can be applied to all specialties of medicine. It is broken down into 5 sections. The first section is a brief overview of government programs, their influence on care delivery and reimbursement, and past and future legislation. Section 2 focuses on the compliance, care provision, and privacy statutes that regulate physicians who care for Medicare/Medicaid patient populations. With a better understanding of these obligations, section 3 discusses avenues by which physicians can stay informed of current and pending health policy and provides ways that they can become involved in shaping future legislation. The fourth section changes gears slightly by explaining how the concepts of trade restraint, libel, antitrust legislation, and indemnity relate to physician practice. The fifth, and final, section ties all of components together by describing how physician-hospital alignment can be mutually beneficial in providing patient care under current healthcare policy legislation.

  13. Real-time X-ray transmission microscopy for fundamental studies solidification: Al-Al2Au eutectic

    NASA Astrophysics Data System (ADS)

    Curreri, Peter A.; Kaukler, William F.; Sen, Subhayu

    1998-01-01

    High resolution real-time X-ray Transmission Microscopy, XTM, has been applied to obtain information fundamental to solidification of optically opaque metallic systems. We have previously reported the measurement of the solute profile in the liquid, phase growth, and detailed solid-liquid interfacial morphology of aluminum based alloys with exposure times less than 2 seconds. Recent advances in XTM furnace design have provided an increase in real-time magnification (during solidification) for the XTM from 40X to 160X. The increased magnification has enabled for the first time the XTM imaging of real-time growth of fibers and particles with diameters of 5 μm. We have previously applied this system to study the kinetics of formation and morphological evolution of secondary fibers and particles in Al-Bi monotectic alloys. In this paper we present the preliminary results of the first real-time observations of fiber morphology evolution in optically opaque bulk metal sample of Aluminum-Gold eutectic alloy. These studies show that the XTM can be applied to study the fundamentals of eutectic and monotectic solidification. We are currently attempting to apply this technology in the fundamentals of solidification in microgravity.

  14. Real-time X-ray transmission microscopy for fundamental studies solidification: Al-Al{sub 2}Au eutectic

    SciTech Connect

    Curreri, Peter A.; Kaukler, William F.; Sen, Subhayu

    1998-01-15

    High resolution real-time X-ray Transmission Microscopy, XTM, has been applied to obtain information fundamental to solidification of optically opaque metallic systems. We have previously reported the measurement of the solute profile in the liquid, phase growth, and detailed solid-liquid interfacial morphology of aluminum based alloys with exposure times less than 2 seconds. Recent advances in XTM furnace design have provided an increase in real-time magnification (during solidification) for the XTM from 40X to 160X. The increased magnification has enabled for the first time the XTM imaging of real-time growth of fibers and particles with diameters of 5 {mu}m. We have previously applied this system to study the kinetics of formation and morphological evolution of secondary fibers and particles in Al-Bi monotectic alloys. In this paper we present the preliminary results of the first real-time observations of fiber morphology evolution in optically opaque bulk metal sample of Aluminum-Gold eutectic alloy. These studies show that the XTM can be applied to study the fundamentals of eutectic and monotectic solidification. We are currently attempting to apply this technology in the fundamentals of solidification in microgravity.

  15. Fundamental interface studies of GaSb and InAs substrates with atomic layer deposition

    NASA Astrophysics Data System (ADS)

    Greer, Frank; Baker, L.; Cook, S.; Fisher, A.; Keo, S.; Soibel, A.; Khoshakhlagh, Arezou; Nguyen, J.; Ting, D.; Gunapala, S.

    2012-10-01

    Long Wavelength infrared photodetectors based on Type-II superlattices from the 6.1Å system hold great promise for a wide variety of applications. However, as these materials are fabricated into focal plane arrays for real world applications, the small pixel sizes that are required can result in unacceptably high dark current due to a significant contribution of surface-induced leakage. These surface currents could be substantially reduced or even eliminated by the application of an appropriate passivation material. But, while a considerable amount of effort has gone into developing passivation processes and materials for these detectors (e.g. PECVD SiO2, polyimides, etc.), there is no one widely adopted standard technique in use today. Atomic layer deposition has the possibility of being an excellent method for depositing passivation because of the wide variety of materials that are readily available via ALD and the ability to conformally coat arbitrary topographies that may be found in the patterning of LWIR FPAs. In this work, fundamental materials characterization results and electrical test data will be presented for two wide band gap, high-K dielectrics (Titanium Oxide and Hafnium Oxide) looking at their nucleation and growth behavior on substrates of relevant III-V materials such as GaSb and InAs using ellispometry, XPS, and XRD. These results will be compared to more conventional passivation strategies to highlight the unique features of the ALD technique.

  16. Fundamental study of a real-time occupational dosimetry system for interventional radiology staff.

    PubMed

    Inaba, Yohei; Chida, Koichi; Kobayashi, Ryota; Kaga, Yuji; Zuguchi, Masayuki

    2014-09-01

    Real-time monitoring of the radiation doses received by interventional radiology (IR) staff has become highly desirable. However, occupational doses are rarely measured in real time, due to the lack of a feasible method for use in IR. Recently, the i2 system by RaySafe™ has been introduced to measure occupational exposure in IR in real time. The i2 system consists of several personal dosimeters (PDs) and a base station with a display and computer interfacing. We evaluated the fundamental performance (dose linearity, dose-rate dependence, angular dependence, batch uniformity and reproducibility) of the i2 system. The dose linearity of the i2 was excellent (R(2) = 1.00) The i2 exhibited slight dose-rate dependence (~20%) at very high dose rates (250 mGy h(-1)). Little angular dependence (within 20%) was observed between 0° and ±45°, in either the vertical or horizontal direction. We also found that the PD was highly sensitive (about 200%) at angles behind it, e.g. 180°. However, this backscattered radiation is not a problem, in general, due to the placement of the i2 sensor (PD) on the lead apron. We conclude that the i2 system facilitates accurate real-time monitoring and management of occupational doses during IR.

  17. A fundamental study of the charge transport and morphology of regioregular poly(3-hexylthiophene)

    NASA Astrophysics Data System (ADS)

    Kline, R. Joseph

    Conjugated polymers include some of the most promising candidates for the active layer of low-cost thin-film transistors (TFTs) and bulk heterojunction photovoltaic (PV) cells. The charge carrier mobility of these conjugated polymers is the key materials property limiting the performance of both of these devices. This thesis outlines a fundamental investigation of the charge transport and morphology of the first high mobility conjugated polymer, regioregular poly(3-hexylthiophene) (P3HT). The charge carrier mobility in TFTs was found to increase by four orders-of-magnitude as the molecular weight (MW) of P3HT is increased from 3000 g/mole to 36,000 g/mole. P3HT films with different MWs provided an ideal system for correlating morphological changes in conjugated polymers to resulting changes in charge transport. Atomic force microscopy, x-ray diffraction and grazing incidence x-ray scattering (GIXS) were used to measure changes in the crystallinity and crystal orientation associated with varying the spin-casting solvent, annealing conditions, substrate surface treatment, and drop-casting at a constant MW. The GIXS results showed that at a constant MW in both low- and high-MW films, the mobility correlated to the strength of in-plane pi-stacking. When comparing different MWs, however, this correlation broke down. Rocking curves on samples with a chemically modified surface showed highly oriented crystals that were nucleated from the substrate and correlate with variations in charge transport. Switching to low-MW P3HT improves the overall crystallinity, the intensity of in-plane pi-stacking, and the concentration of highly oriented crystals, but the mobility is more than a factor of 100 lower than high-MW P3HT. These counterintuitive results clearly show that the charge carrier mobility of conjugated polymers is coupled to several different aspects of the morphology. In the case of the low-MW films, the strong driving force for ordering creates grain boundaries that

  18. NMR relaxometry study of plaster mortar with polymer additives

    SciTech Connect

    Jumate, E.; Manea, D.; Moldovan, D.; Fechete, R.

    2013-11-13

    The cement mixed with water forms a plastic paste or slurry which stiffness in time and finally hardens into a resistant stone. The addition of sand aggregates, polymers (Walocel) and/or calcium carbonate will modify dramatically the final mortar mechanic and thermal properties. The hydration processes can be observed using the 1D NMR measurements of transverse T{sub 2} relaxation times distributions analysed by a Laplace inversion algorithm. These distributions were obtained for mortar pasta measured at 2 hours after preparation then at 3, 7 and 28 days after preparation. Multiple components are identified in the T{sub 2} distributions. These can be associated with the proton bounded chemical or physical to the mortar minerals characterized by a short T{sub 2} relaxation time and to water protons in pores with three different pore sizes as observed from SEM images. The evaporation process is faster in the first hours after preparation, while the mortar hydration (bonding of water molecules to mortar minerals) can be still observed after days or months from preparation. Finally, the mechanic resistance was correlated with the transverse T{sub 2} relaxation rates corresponding to the bound water.

  19. Testing Our Fundamental Assumptions

    NASA Astrophysics Data System (ADS)

    Kohler, Susanna

    2016-06-01

    fundamental assumptions.A recent focus set in the Astrophysical Journal Letters, titled Focus on Exploring Fundamental Physics with Extragalactic Transients, consists of multiple published studies doing just that.Testing General RelativitySeveral of the articles focus on the 4th point above. By assuming that the delay in photon arrival times is only due to the gravitational potential of the Milky Way, these studies set constraints on the deviation of our galaxys gravitational potential from what GR would predict. The study by He Gao et al. uses the different photon arrival times from gamma-ray bursts to set constraints at eVGeV energies, and the study by Jun-Jie Wei et al. complements this by setting constraints at keV-TeV energies using photons from high-energy blazar emission.Photons or neutrinos from different extragalactic transients each set different upper limits on delta gamma, the post-Newtonian parameter, vs. particle energy or frequency. This is a test of Einsteins equivalence principle: if the principle is correct, delta gamma would be exactly zero, meaning that photons of different energies move at the same velocity through a vacuum. [Tingay Kaplan 2016]S.J. Tingay D.L. Kaplan make the case that measuring the time delay of photons from fast radio bursts (FRBs; transient radio pulses that last only a few milliseconds) will provide even tighter constraints if we are able to accurately determine distances to these FRBs.And Adi Musser argues that the large-scale structure of the universe plays an even greater role than the Milky Way gravitational potential, allowing for even stricter testing of Einsteins equivalence principle.The ever-narrower constraints from these studies all support GR as a correct set of rules through which to interpret our universe.Other Tests of Fundamental PhysicsIn addition to the above tests, Xue-Feng Wu et al. show that FRBs can be used to provide severe constraints on the rest mass of the photon, and S. Croft et al. even touches on what we

  20. Fundamental studies of high-temperature corrosion reactions. Fifth annual progress report

    SciTech Connect

    Rapp, R.A.

    1980-02-01

    The in-situ study of metal oxidation reactions and the mechanism of the sulfidation of molybdenum by sulfur gases were studied. Equipment including a SEM microscope, heater and power supply which were used is described. (FS)

  1. Fundamental studies of fluid mechanics and stability in porous media. Progress report

    SciTech Connect

    Homsy, G.M.

    1992-07-01

    We have been active in four areas: Numerical and analytical studies of viscous fingering in miscible displacements, including non- monotonic mobility profiles; numerical and analytical studies of the effect of non-Newtonian fluid characteristics on instabilities; experimental studies of instabilities of moving contact lines for Newtonian and non-Newtonian fluids; and studies of natural convective energy transport due to time-dependent body forces.

  2. The Testing Effect: Illustrating a Fundamental Concept and Changing Study Strategies

    ERIC Educational Resources Information Center

    Einstein, Gilles O.; Mullet, Hillary G.; Harrison, Tyler L.

    2012-01-01

    An important recent finding is that testing improves learning and memory. In this article, the authors describe a demonstration that illustrates this principle and helps students incorporate more testing into their learning. The authors asked students to read one text using a Study-Study strategy and one text using a Study-Test strategy. One week…

  3. Study Guide for Fundamentals of Solar Heating: A Correspondence Course for the Airconditioning Industry.

    ERIC Educational Resources Information Center

    Sheet Metal and Air Conditioning Contractors National Association, Vienna, VA.

    This study guide groups eleven lessons into four study units. The first unit discusses the development and basic concepts of solar heating. The second unit deals with the nomenclature of the solar heating system. The third study unit covers sizing of the solar heating system to meet demand and discusses the operation of the total system. The…

  4. Additional EIPC Study Analysis: Interim Report on High Priority Topics

    SciTech Connect

    Hadley, Stanton W

    2013-11-01

    Between 2010 and 2012 the Eastern Interconnection Planning Collaborative (EIPC) conducted a major long-term resource and transmission study of the Eastern Interconnection (EI). With guidance from a Stakeholder Steering Committee (SSC) that included representatives from the Eastern Interconnection States Planning Council (EISPC) among others, the project was conducted in two phases. Phase 1 involved a long-term capacity expansion analysis that involved creation of eight major futures plus 72 sensitivities. Three scenarios were selected for more extensive transmission- focused evaluation in Phase 2. Five power flow analyses, nine production cost model runs (including six sensitivities), and three capital cost estimations were developed during this second phase. The results from Phase 1 and 2 provided a wealth of data that could be examined further to address energy-related questions. A list of 13 topics was developed for further analysis; this paper discusses the first five.

  5. Additional studies for the spectrophotometric measurement of iodine in water

    NASA Technical Reports Server (NTRS)

    1972-01-01

    Previous work in iodine spectroscopy is briefly reviewed. Continued studies of the direct spectrophotometric determination of aqueous iodine complexed with potassium iodide show that free iodine is optimally determined at the isosbestic point for these solutions. The effects on iodine determinations of turbidity and chemical substances (in trace amounts) is discussed and illustrated. At the levels tested, iodine measurements are not significantly altered by such substances. A preliminary design for an on-line, automated iodine monitor with eventual capability of operating also as a controller was analyzed and developed in detail with respect single beam colorimeter operating at two wavelengths (using a rotating filter wheel). A flow-through sample cell allows the instrument to operate continuously, except for momentary stop flow when measurements are made. The timed automatic cycling of the system may be interrupted whenever desired, for manual operation. An analog output signal permits controlling an iodine generator.

  6. Variability in Fundamental Frequency during Speech in Prodromal and Incipient Parkinson's Disease: A Longitudinal Case Study

    ERIC Educational Resources Information Center

    Harel, Brian; Cannizzaro, Michael; Snyder, Peter J.

    2004-01-01

    Nearly two centuries ago, Parkinson (1817) first observed that a particular pattern of speech changes occur in patients with idiopathic Parkinson's disease (PD). Numerous studies have documented these changes using a wide variety of acoustic measures, and yet few studies have attempted to quantify any such changes longitudinally, through the early…

  7. Fundamental studies of hydrogen interaction with supported meta and bimetallic catalysts

    SciTech Connect

    Bhatia, S.

    1993-12-07

    The thesis is divided into 3 parts: interaction of H with silica supported Ru catalysts (high pressure in situ NMR), in situ NMR study of H interaction with supported Ru-group IB bimetallic catalysts, and in-situ NMR study of H effects on silica-supported Pt, Rh and Ru catalysts.

  8. Fundamental studies of fluid mechanics and stability in porous media. Progress report

    SciTech Connect

    Homsy, G.M.

    1993-08-01

    This progress report covers our work over the last grant period (1990-1993). Work has been in the following areas: semi-analytical studies of enhanced energy transport in natural convection due to time dependent body forces; large scale simulations of non-linear instabilities in porous media flow for situations of interest in petroleum recovery; analytical studies of `chimney` formation in unstable freezing mixtures; analytical and experimental studies of contact line dynamics for Newtonian and non-Newtonian fluids; and large scale numerical simulations of shear instabilities of viscoelastic fluids.

  9. Fundamental studies of coal liquefaction. Quarterly report No. 6, January 1--April 1, 1993

    SciTech Connect

    Ross, D.S.

    1993-05-04

    Figures 3, 4, and 5 display images of two adjacent particles chosen for analysis with characteristic dimensions of 50--100 {mu}m Figure 3 shows that there is essentially no change up to 395{degrees}C over an 18 min period, but at that point the particle labeled a begins to shrink. The action continues in Figure 4 where the particle contracts to about half its initial size over a 45 sec period as the temperature, increases from 424{degrees}C to 430{degrees}C, at which point the contraction stops. The size profile for a is presented in Figure 6 and compares very well with the profile generated in an earlier experiment from our last report. As just noted, this agreement suggests that this behavior is representative of at least one class of particle in the sample. Figure 5 shows that there is a second, higher temperature range of activity, represented by the changes in particle b. This particle contracts to about half its size from 450{degrees} to 460{degrees}C over 1 min. The temperature was held at 460{degrees} and there appears to be an additional 7--10% contraction over 10 min at that temperature, although the scatter seen in Figure 6 shows that change is not outside our error limits. We conclude that the process takes place rapidly and concludes within initial 1 min period.

  10. Fundamental study of flow field generated by rotorcraft blades using wide-field shadowgraph

    NASA Technical Reports Server (NTRS)

    Parthasarathy, S. P.; Cho, Y. I.; Back, L. H.

    1985-01-01

    The vortex trajectory and vortex wake generated by helicopter rotors are visualized using a wide-field shadowgraph technique. Use of a retro-reflective Scotchlite screen makes it possible to investigate the flow field generated by full-scale rotors. Tip vortex trajectories are visible in shadowgraphs for a range of tip Mach number of 0.38 to 0.60. The effect of the angle of attack is substantial. At an angle of attack greater than 8 degrees, the visibility of the vortex core is significant even at relatively low tip Mach numbers. The theoretical analysis of the sensitivity is carried out for a rotating blade. This analysis demonstrates that the sensitivity decreases with increasing dimensionless core radius and increases with increasing tip Mach number. The threshold value of the sensitivity is found to be 0.0015, below which the vortex core is not visible and above which it is visible. The effect of the optical path length is also discussed. Based on this investigation, it is concluded that the application of this wide-field shadowgraph technique to a large wind tunnel test should be feasible. In addition, two simultaneous shadowgraph views would allow three-dimensional reconstruction of vortex trajectories.

  11. Fundamental studies of gas phase ionic reactions by ion mobility spectrometry

    NASA Technical Reports Server (NTRS)

    Giles, K.; Knighton, W. B.; Sahlstrom, K. E.; Grimsrud, E. P.

    1995-01-01

    Ion mobility spectrometry (IMS) provides a promising approach to the study of gas phase ionic reactions in buffer gases at unusually high pressures. This point is illustrated here by studies of the Sn2 nucleophilic displacement reaction, Cl(-) + CH3Br yields Br + CH3Br, using IMS at atmospheric pressure. The equilibrium clustering reaction, Cl(-)(CHCI3)(n - 1) + CHCI3 yields Cl(-)(CHCI3)(n), where n = 1 and 2, and the effect of clustering on the Sn2 reaction with CH3Br have also been characterized by this IMS-based kinetic method. Present problems and anticipated improvements in the application of ion mobility spectrometry to studies of other gas phase ionic processes are discussed.

  12. Fundamental studies of the properties of photoresists based on resins containing polymer-bound photoacid generators

    NASA Astrophysics Data System (ADS)

    Lee, Cheng-Tsung; Jarnagin, Nathan D.; Wang, Mingxing; Gonsalves, Kenneth E.; Robert, Jeanette M.; Yueh, Wang; Henderson, Clifford L.

    2006-03-01

    Conventional chemically amplified photoresist formulations are complex mixtures that include a protected polymer resin and a small molecule photoacid generator (PAG). The limited compatibility of the PAG with resist resin and the mobility of the small molecule additive can lead to problems including PAG phase separation, non-uniform initial PAG and photoacid distribution, and acid migration during the post-exposure baking (PEB) processes. The incorporation of PAG units into the main chain of the polymer resin is one possible method to alleviate these problems. Recently, we have investigated methacrylate based resists which incorporate novel PAG functional groups into the polymer main chain. These materials have demonstrated good resolution performance for both 193 nm and EUV exposure for sub-100 nm patterning. However, limited information is available on the effect of binding the PAG to the polymer on PAG photoreactivity and photoacid diffusivity. In this work, the photoacid generation rate constant (commonly referred to as the Dill C parameter for the PAG) of both triflate polymer-bound PAG and blended PAG photoresists based on poly(γ-butyrolactone methacrylate -co-2-ethyl-2-adamantyl methacrylate ) resists were determined by a new technique utilizing both quantitative FTIR spectroscopy and kinetic model fitting. The results indicate that the polymer-bound PAG resist has a lower photoacid generation rate constant (C=0.0122) than the blend PAG one (C=0.2647). This large difference in Dill C parameters would indicate that the sensitivity of the polymer-bound PAG resist is substantially lower than that of the analogous blended sample which is consistent with contrast curve data for these two samples.

  13. Fundamental studies of catalytic gasification. Quarterly report, July 1--September 30, 1991

    SciTech Connect

    Heinemann, H.; Somorjai, G.A.

    1991-09-01

    In this project a considerable number of important findings have been made. Leads for scale-up have been developed and mechanisms for the reaction have been delineated. A small amount of additional experimental work is necessary and the extensive body of this project must be summarized in a final report. Recently limited experimentation has been carried out on the production of C{sub 2} hydrocarbons from methane in the presence of Ca/K/Ni oxide catalysts and of oxygen, carbon and water. The main finding thus far has been that C{sub 2} yields of 10--13% can be obtained at about 600{degrees}C or 150{degrees} lower temperature than described in the literature for similar yields. Occasionally much higher yields were obtained and reasons for this must be determined. We have recently found that with a modified catalyst and by operating at quite low temperature ({approx}600{degrees}C) CO{sub 2} formation can be almost totally suppressed. Yields of 7--10% C{sub 2} hydrocarbons at 99+% selectivity have been obtained. The presence of water and small amounts of oxygen is essential. Yields of this magnitude may be attractive since there is no loss of methane to valueless by-products, no purification of the recycle steam is required and no oxygen is used to burn methane. Further improvement in yields by catalyst and operating conditions modifications will be investigated. It is also intended to clarify the chemistry which inhibits burning of methane to carbon oxides.

  14. Twelve Factors Leading to Fundamental Pedagogical Change in a Primary School: A Case-Study

    ERIC Educational Resources Information Center

    Norris, Cathleen; Soloway, Elliot

    2016-01-01

    A school can change. In this case study, the authors describe the 12 factors they have identified as being key in the transformation of the core pedagogical practices at Nan Chiau Primary School, Singapore, from direct instruction to inquiry, from a 20th to a 21st century school. While the adoption of 1:1 mobile devices played a catalytic role in…

  15. Using Baseball in Social Studies Instruction: Addressing the Five Fundamental Themes of Geography

    ERIC Educational Resources Information Center

    Edgington, William D.; Hyman, William

    2005-01-01

    Many children do not enjoy social studies because they see it as having little, if any, relevance to their lives. That response is attributable primarily to two factors: Dry content and even drier instructional strategies. Teachers know that if material presented to children is not meaningful and relevant to their lives, real learning does not…

  16. Exploratory cell research and fundamental processes study in solid state electrochemical cells

    SciTech Connect

    Smyrl, W.H.; Owens, B.B.; White, H.S. . Dept. of Chemical Engineering and Materials Science)

    1990-06-01

    Last year this program demonstrated that alternative to lithium had some merit on which to base new polymer electrolyte batteries and other electrochemical devices. We reported that Na, Zn, and Cu electrolytes have modest conductivities at 100{degree}C. Some preliminary cell cycling data were reported with V{sub 6}O{sub 13} insertion cathodes, and the successful cell cycling suggested that N{sup +}, Zn{sup +2} could be inserted and removed reversibly in the cathode material. Also, thin-film polymer cathodes were shown by impedance measurements to have three characteristic regions of behavior. Each region had different controlling processes with relaxation time constants that could be separated with careful manipulation of film thickness, morphology, and charging level. The present report gives results of the continuation of these studies. In particular, the sodium system was studied more intensively with conductivity measurements on sodium triflate in poly(ethyleneoxide)(PEO), and cell studies with V{sub 6}O{sub 13} and poly(pyrrole)(PPY) cathodes. The impedance work was concluded and several directions of new work in that area were identified. The insertion studies with single crystal V{sub 6}O{sub 13} were concluded on this program and transferred to NSF funding. 29 refs., 6 figs., 6 tabs.

  17. Fundamental studies of quantum codes and gates for building a reliable quantum computer

    NASA Astrophysics Data System (ADS)

    Siddiqui, Shabnam

    In this dissertation we have studied various methods that have been proposed to overcome the problem of decoherence in a quantum computer. These methods are: (1) Quantum-error correcting codes (QECC's); (2) Decoherence-free subsystem/subspace (DFS); (3) Adiabatic gate operation. In the first two methods, information is encoded in the form of a code that provides protection against certain noise and hence protect the qubit from losing information to the environment. In the third method, the gate operation is performed in such a way that the qubit is made to evolve adiabatically because of which it acquires a phase which is insensitive to the certain form of noise. Thus, because of the insensivity of the phase to the noise, the qubit is prevented from losing information to the environment. All these methods have limitations and in this work we studied these limitations. This work is divided into two parts. In the first part, we studied the performance of a 3-qubit QECC in the presence of quantized partially correlated noise, as well as 3 and 4-qubit DFS in the presence of partially correlated noise. We derived the relationship between the fidelity of the code, the initial state, coherence length of the noise and the spatial distance between the qubits. For the case of, 3-qubit QECC we found that the quantum nature of the noise enhances the infidelity of the code. For the case of, 3 and 4-qubit DFS we found that under certain conditions 3-qubit DFS code is a better code over 4-qubit code. Nonetheless, these studies provide us insights of the influence of the environment on the performance of quantum codes. In the second part, we studied the problem of the entanglement of the coherent field (that is used to turn on/off the gate) with the qubit on which gate operation is performed. The gate operation is made adiabatic by making the coherent field to change very slowly in time. The entanglement arises due to the quantum nature of the coherent field and causes faulty gate

  18. Fundamental Studies on Two-Phase Gas-Liquid Flows Through Packed Beds in Microgravity

    NASA Technical Reports Server (NTRS)

    Balakotaiah, Vemuri; McCready, Mark J.; Motil, Brian J.

    2002-01-01

    evaluated along with a companion set of tests in normal gravity. The flow rates, fluid properties and packing properties were selected to provide a range of several orders-of-magnitude for the important dimensionless parameters. Additional information is included in the original extended abstract.

  19. A fundamental study of the sticking of insect residues to aircraft wings

    NASA Technical Reports Server (NTRS)

    Eiss, N. S., Jr.; Wightman, J. P.; Gilliam, D. R.; Siochi, E. J.

    1985-01-01

    The aircraft industry has long been concerned with the increase of drag on airplanes due to fouling of the wings by insects. The present research studied the effects of surface energy and surface roughness on the phenomenon of insect sticking. Aluminum plates of different roughnesses were coated with thin films of polymers with varying surface energies. The coated plates were attached to a custom jig and mounted on top of an automobile for insect collection. Contact angle measurements, X-ray photoelectron spectroscopy and specular reflectance infrared spectroscopy were used to characterize the surface before and after the insect impact experiments. Scanning electron microscopy showed the topography of insect residues on the exposed plates. Moments were calculated in order to find a correlation between the parameters studied and the amount of bugs collected on the plates. An effect of surface energy on the sticking of insect residues was demonstrated.

  20. Fundamental studies of the mechanisms of slag deposit formation: Final report

    SciTech Connect

    Austin, L.G.; Benson, S.; Rabinovich, A.; Tangsathitkulchai, M.; Schobert H.H.

    1987-07-01

    The kinetics of ash deposition on utility boilers have been studied. A heated tube furnace system was used in the study. Areas of consideration in the deposition mechanics were: close space knowledge of chemical composition and distribution of inorganic constituents in coal, transformations and reactions of the inorganic constituents in the flame, ash transport mechanisms, initial adhesion of ash particles to heat transfer surfaces and subsequently to each other to form a deposit, and further interactions of the deposited ash to grow a strong deposit. Interactions of deposited ash that cause changes in physical and chemical properties in an aged deposit are due to processes such as sintering, chemical reactions, and melting. The degree of these changes increases as the deposit grows from the heat transfer surfaces where it forms. All of these changes during the deposit formation process are coal-specific and are strongly dependent on the boiler configuration and operating conditions. 18 refs., 55 figs., 42 tabs.

  1. The use of analytical surface tools in the fundamental study of wear. [atomic nature of wear

    NASA Technical Reports Server (NTRS)

    Buckley, D. H.

    1977-01-01

    Various techniques and surface tools available for the study of the atomic nature of the wear of materials are reviewed These include chemical etching, x-ray diffraction, electron diffraction, scanning electron microscopy, low-energy electron diffraction, Auger emission spectroscopy analysis, electron spectroscopy for chemical analysis, field ion microscopy, and the atom probe. Properties of the surface and wear surface regions which affect wear, such as surface energy, crystal structure, crystallographic orientation, mode of dislocation behavior, and cohesive binding, are discussed. A number of mechanisms involved in the generation of wear particles are identified with the aid of the aforementioned tools.

  2. Fundamental studies of passivity and passivity breakdown. Final report, [September 1993--September 1994

    SciTech Connect

    Macdonald, D.D.; Urquidi-Macdonald, M.

    1994-02-21

    Purpose is to understand the mechanisms for growth and breakdown of passive films on metal and alloy surfaces in aqueous medium; a secondary goal is to devise methods for predicting localized corrosion damage in industrial systems. Tasks currently being studied are: formation of bilayer structures in passive films on metals and alloys; passivity breakdown on solid vs. liquid gallium; roles of alloying elements in passivity breakdown; electrochemical impedance spectroscopy of passive films; electronic structure of passive oxide films; photoelectrochemical impedance spectroscopy of passive films; and kinetics of localized attack.

  3. Fundamental studies of coal liquefaction. Quarterly report No. 4, July 1--October 1, 1992

    SciTech Connect

    Ross, D.S.

    1992-12-04

    SRI International is conducting studies of the effects of liquid water at temperatures and pressures near its critical point on the behavior of coal. The present study involves the construction and operation of a cell for visual observation of the process. The cell is batch charged with a dispersion of coal particles in solvent; it is designed for continuous flow operation should that mode of operation become desirable. It can be electrically heated to 550{degree}C and can handle pressures to 5000 psi. Direct observation of individual particles takes place through a pair of diamond windows, a lens assembly, and a television monitoring system. A number of runs have been performed during this quarter, including runs with Wyodak and Illinois No. 6 coal with both water and tetralin. A video tape of two runs was submitted with a monthly report during this quarter, and a tape with four runs in included with this report. Unfortunately just as our experience with the cell was developing, one of the diamonds cracked and the replacement is not expected before December. Accordingly we have spent some time operating the cell with a single window and front lighting.

  4. Long-term importance of fundamental motor skills: a 20-year follow-up study.

    PubMed

    Lloyd, Meghann; Saunders, Travis J; Bremer, Emily; Tremblay, Mark S

    2014-01-01

    The purpose of this study was to investigate the potential long-term association of motor skill proficiency at 6 years of age and self-reported physical activity (PA) at age 26. Direct motor performance data were collected in 1991 with a follow-up study occurring in 1996, and then indirect questionnaires (self-report) administered in 2001 and 2011. In 2011, 17 participants who were identified as either having high motor proficiency (HMP) or low motor proficiency (LMP) in 1991 completed a series of 4 questionnaires. Analyses were conducted to determine whether there were differences between groups for motor skill proficiency, PA, or sedentary behavior, and whether these outcomes were related across ages. Motor skill proficiency at age 6 was related to self-reported proficiency at age 16 (r = .77, p = .006), and self-reported proficiency between 16 and 26 years (r = .85, p = .001). Motor skill proficiency at age 6 was positively associated with leisure time PA at age 26 in females and participants in the HMP group. The results may provide preliminary evidence about the importance of how early motor skill proficiency relates to long-term PA. More research with larger sample sizes is needed to investigate the importance of motor skills over time.

  5. Development of critical attitude in fundamentals of professional care discipline: a case study.

    PubMed

    Waterkemper, Roberta; do Prado, Marta Lenise; Medina, Jose Luis Moya; Reibnitz, Kenya Schmidt

    2014-04-01

    This is a qualitative case study to identify the contributions of a critical pedagogical technique in developing critical attitudes of graduating nursing students in Brazil. Fourteen students participated in this study. Data were collected from March to August 2010 using triangulation of non-participant observation, interview and document analysis. The collected data were transcribed to Word documents, which were subsequently imported into ATLAS.ti, version 6.2, for organisation and qualitative data analysis. The analysis was based on the work of Minayo (2010). The following three thematic analysis units were constructed: feeling free - seeking the liberty to learn to admire, admiring by curiosity and reflecting about the admired object. The results of the thematic categories reveal that the students understand that they are free to have an active role in their education, and the teacher facilitates this process; thus, the students have a raison d'ètre, or reason for being, free. Feeling free, the student can exercise their curiosity when facing the given situations and topics, which challenges them to make decisions based on their awareness of the world. PMID:23968668

  6. Fundamental study of the mechanism and kinetics of cellulose hydrolysis by acids and enzymes

    NASA Astrophysics Data System (ADS)

    Gong, C. S.; Chang, M.

    1981-02-01

    There are three basic enzymes e.g., endoglucanase (C/sub x/), exoglucanase (C1) and cellobiase comprising the majority of extracellular cellulase enzymes produced by the cellulolytic mycelial fungi, Trichoderma reesei, and other cellulolytic microorganisms. The kinetics of cellobiase were developed on the basis of applying the pseudo-steady state assumption to hydrolyze cellobiose to glucose. The results indicated that cellobiase was bjected to end-product inhibition by glucose. The kinetic modeling of exoglucanase (C1) with respect to cellodextrins was studied. Both glucose and cellobiose were found to be inhibitors of this enzyme with cellobiose being a stronger inhibitor than glucose. Similarly, endoglucanase (C/sub x) is subject to end-product inhibition by glucose. Crystallinity of the cellulose affects the rate of hydrolysis by cellulases. Hence, the changes in crystallinity of cellulose in relation to chemical pretreatment and enzyme hydrolysis was compared. The study of cellulase biosynthesis resulted in the conclusion that exo-and endo-glucanases are coinduced while cellobiase is synthesized independent of the other two enzymes.

  7. ''Decoupled method'' for studying large interconnected grounding systems using microcomputers - Part I - Fundamentals

    SciTech Connect

    Sobral, S.T. ); Fleury, V.G.P. ); Villalba, J.R. ); Mukhedkar, D. )

    1988-10-01

    Interconnected ground systems with hundreds of even thousands of circuit elements are relatively frequent in the electrical industry. If used the common matricial representation of the complete ground circuit, the quality of the solution decreases with the size of the circuit, due to the propagation of the relative error of each circuit element. For very large circuits, all digits of a solution can become non-significant. This paper presents the ''Decoupled Method'' (1), (2), (7), (8), which is a set of procedures allowing the determination of an equivalent circuit generally 10-60 times smaller than the original one. The flow-chart of the corresponding computer program is also presented. The reduced size of this equivalent circuit avoids the error propagation and allows even huge ground systems to be studied using microcomputers. A companion paper presents the theoretical justification of some techniques used in this paper, and also shows how the ''Decoupled Method'' was used for studying and detailing important ground facilities of the 1300 MW Itaipu Generation Complex (including four large nearby substations interconnected through ACSR ground-wires of several 500 kV and 220 kV transmission lines). It is shown that field measurements bear out the computed values.

  8. Emotions beyond the laboratory: theoretical fundaments, study design, and analytic strategies for advanced ambulatory assessment.

    PubMed

    Wilhelm, Frank H; Grossman, Paul

    2010-07-01

    Questionnaire and interview assessment can provide reliable data on attitudes and self-perceptions on emotion, and experimental laboratory assessment can examine functional relations between stimuli and reactions under controlled conditions. On the other hand, ambulatory assessment is less constrained and provides naturalistic data on emotion in daily life, with the potential to (1) assure external validity of laboratory findings, (2) provide normative data on prevalence, quality and intensity of real-life emotion and associated processes, (3) characterize previously unidentified emotional phenomena, and (4) model real-life stimuli for representative laboratory research design. Technological innovations now allow for detailed ambulatory study of emotion across domains of subjective experience, overt behavior and physiology. However, methodological challenges abound that may compromise attempts to characterize biobehavioral aspects of emotion in the real world. For example, emotional effects can be masked by social engagement, mental and physical workloads, as well as by food intake and circadian and quasi-random variation in metabolic activity. The complexity of data streams and multitude of factors that influence them require a high degree of context specification for meaningful data interpretation. We consider possible solutions to typical and often overlooked issues related to ambulatory emotion research, including aspects of study design decisions, recording devices and channels, electronic diary implementation, and data analysis. PMID:20132861

  9. Fundamental studies in production of C[sub 2]-C[sub 4] hydrocarbons from coal

    SciTech Connect

    Wiser, W.H.; Oblad, A.G.

    1993-03-01

    The following conclusions can be drawn from the result obtained in this kinetic study of single stage coal gasification to hydrocarbon (HC) gases high in C[sub 2]-C[sub 4] hydrocarbons. It was observed that the direct conversion of coal to HC gases involves two steps. The first step is thermal cleavage of the coal structure to produce liquids with small amounts of gases and coke. The second step is conversion of liquids to gases. Coal to liquids occurs very rapidly and was completed within 10 minutes. Liquids to gases is the rate-determining step of the overall process. The conversion of liquids to gases was observed to follow first order kinetics. The first order kinetics treatment of the data by isothermal approximation gave an apparent activation energy of approximately 23 kcal/mol. The first order kinetics treatment of the data by a more rigorous non-isothermal method gave an activation energy of 26 kcal/mol. The quantity of HC gases produced directly from coal reached a constant value of about l0% of the dmmf coal at a reaction time of 10 miutes. Most of the HC gases were produced from the liquids. The study of model compounds shows that conversion of liquids to HC gases.proceeds through a carbonium ion mechanism, and this accounts for the production of C[sub 2]-C[sub 4] gases. Liquid to gases occurs by a catalytic hydrocracking reaction.

  10. Fundamental Studies of Assembly and Mechanical Properties of Lipid Bilayer Membranes and Unilamellar Vesicles

    NASA Astrophysics Data System (ADS)

    Wang, Xi

    This dissertation work focuses on: (i) obtaining a phospholipid bilayer membrane (LBM)/conducting electrode system with low defect density and optimized rigidity; (ii) investigating vesicle stability and mechanical properties. LBM is a simplified yet representative cell membrane model. LBMs assembled on conductive surfaces can probe protein-LBM interactions activities electrochemically. Sterically stabilized vesicles could be used as cell models or for drug delivery. The main challenges for LBM assembly on gold are vesicles do not spontaneously rupture to form LBMs on gold and the roughness of the gold substrate has considerable influence on molecular film defect density. In this study, 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC) vesicles were functionalized with 1,2-distearoyl-sn-glycero-3-phosphoethanolamine- N-poly(ethylene glycol)-2000-N-[3-(2-pyridyldithio)propionate] (DSPE-PEG-PDP) to yield stable LBMs on gold without surface modification. A template-stripping method was used to obtain atomically flat and pristine gold surfaces. The critical force to initiate vesicle rupture decreases with increasing DSPE-PEG-PDP concentration, indicating that gold-thiolate bonding between DSPE-PEG-PDP and gold substrates promotes LBM formation. Mechanical properties of LBMs and vesicles were investigated as a function of DSPE-PEG-PDP concentration via Atomic Force Microscopy. The elastic moduli of LBMs were determined with DSPE-PEG-PDP concentration ranging from 0mol% to 24mol% and were found to depend on PEG chain conformation. Incorporating DSPE-PEG-PDP molecules with PEG in mushroom conformation results in a decrease of LBM rigidity, while incorporating PEG in brush conformation leads to LBM stiffening. Contrarily, mechanical properties of functionalized vesicles did not vary significantly by varying DSPE-PEG-PDP concentration. LBM with tunable rigidity by adjusting DSPE-PEG-PDP concentration provides a versatile cell membrane model for studying protein or

  11. Fundamental studies of separation processes. Technical progress report, 15 August 1979-14 August 1980

    SciTech Connect

    Rogers, L.B.

    1980-01-01

    During the past year, four technical reports have been issued. These have dealt with relative retentions in gas chromatography of the sulfur isotopes in COS, CS/sub 2/ and SO/sub 2/, fractionations of oligomers in commercial polystyrene, identifications of classes of compounds removed from different types of carbonaceous materials by supercritical pentane, and a comparison of the speed of a system of multiple isothermal columns with that of a programmed-temperature column for the fractionation of a mixture of compounds covering a wide range of boiling points. Other studies have involved optimization of the recycle mode in gas chromatography, selective weighting of peaks in the measurement of information conveyed by a chromatogram, development of procedures for the isolations of various vanadium compounds from Venezuelan crude oil, and evaluation of the effect of organic ligand on the sensitivity of the flame emission signal observed for vanadium.

  12. A Fundamental Study for Aerodynamic Characteristics of Supersonic Biplane Wing and Wing-Body Configurations

    NASA Astrophysics Data System (ADS)

    Odaka, Yusuke; Kusunose, Kazuhiro

    In order to develop a quiet supersonic transport, it is necessary to reduce shock waves around the transport. Shock waves, in general, are the cause of the airplane's sonic boom. Authors have been studying an aerodynamic feasibility of supersonic biplanes based on the concept of the Busemann biplane. In this paper, the three dimensional effect of wing geometries on their wave drags, including wing tip effects and the interference effects between the wing and a body (Wing-Body configurations) are investigated, using CFD code in Euler (inviscid) mode. As a result, we can conclude that the supersonic biplane wings at their design Mach number (M∞=1.7) are still capable of reducing wave drag significantly similar to that of the 2-D supersonic biplane.

  13. Fundamental studies of radar scattering from water surfaces: The Lake Washington experiment

    NASA Technical Reports Server (NTRS)

    Salam, A.; Bush, D.; Gogineni, S.; Zaide, A.

    1991-01-01

    The University of Kansas and the University of Washington conducted a series of experiments during July and August of 1989, and July and August of 1990, to study the effects of various geophysical parameters on radar backscatter. The experiments were conducted from a platform in Lake Washington. Measurements of backscattered power and radar range were made by the University of Kansas, and environmental data such as wind speed, wind direction, and air and water temperature were measured by the University of Washington. Results of preliminary data processing are described. Radar data were acquired using two radars, one that operated at C and X bands and another at Ka band. Measurements were made at W and HH antenna polarizations, at different angles of incidence and under various wind conditions. Plots of backscattered power, normalized radar cross section, and wave height, and the Modulation Transfer Functions of selected data are presented.

  14. Formation of imploding plasma liners for fundamental HEDP studies and MIF Standoff Driver Concept

    SciTech Connect

    Cassibry, Jason; Hatcher, Richard; Stanic, Milos

    2013-08-17

    The disciplines of High Energy Density Physics (HEDP) and Inertial Confinement Fusion (ICF) are characterized by hypervelocity implosions and strong shocks. The Plasma Liner Experiment (PLX) is focused on reaching HEDP and/or ICF relevant regimes in excess of 1 Mbar peak pressure by the merging and implosion of discrete plasma jets, as a potentially efficient path towards these extreme conditions in a laboratory. In this work we have presented the first 3D simulations of plasma liner, formation, and implosion by the merging of discrete plasma jets in which ionization, thermal conduction, and radiation are all included in the physics model. The study was conducted by utilizing a smoothed particle hydrodynamics code (SPHC) and was a part of the plasma liner experiment (PLX). The salient physics processes of liner formation and implosion are studied, namely vacuum propagation of plasma jets, merging of the jets (liner forming), implosion (liner collapsing), stagnation (peak pressure), and expansion (rarefaction wave disassembling the target). Radiative transport was found to significantly reduce the temperature of the liner during implosion, thus reducing the thermal leaving more pronounced gradients in the plasma liner during the implosion compared with ideal hydrodynamic simulations. These pronounced gradients lead to a greater sensitivity of initial jet geometry and symmetry on peak pressures obtained. Accounting for ionization and transport, many cases gave higher peak pressures than the ideal hydrodynamic simulations. Scaling laws were developed accordingly, creating a non-dimensional parameter space in which performance of an imploding plasma jet liner can be estimated. It is shown that HEDP regimes could be reached with ~ 5 MJ of liner energy, which would translate to roughly 10 to 20 MJ of stored (capacitor) energy. This is a potentially significant improvement over the currently available means via ICF of achieving HEDP and nuclear fusion relevant parameters.

  15. The Anisakis Transcriptome Provides a Resource for Fundamental and Applied Studies on Allergy-Causing Parasites

    PubMed Central

    Baird, Fiona J.; Su, Xiaopei; Aibinu, Ibukun; Nolan, Matthew J.; Sugiyama, Hiromu; Otranto, Domenico

    2016-01-01

    Background Food-borne nematodes of the genus Anisakis are responsible for a wide range of illnesses (= anisakiasis), from self-limiting gastrointestinal forms to severe systemic allergic reactions, which are often misdiagnosed and under-reported. In order to enhance and refine current diagnostic tools for anisakiasis, knowledge of the whole spectrum of parasite molecules transcribed and expressed by this parasite, including those acting as potential allergens, is necessary. Methodology/Principal Findings In this study, we employ high-throughput (Illumina) sequencing and bioinformatics to characterise the transcriptomes of two Anisakis species, A. simplex and A. pegreffii, and utilize this resource to compile lists of potential allergens from these parasites. A total of ~65,000,000 reads were generated from cDNA libraries for each species, and assembled into ~34,000 transcripts (= Unigenes); ~18,000 peptides were predicted from each cDNA library and classified based on homology searches, protein motifs and gene ontology and biological pathway mapping. Using comparative analyses with sequence data available in public databases, 36 (A. simplex) and 29 (A. pegreffii) putative allergens were identified, including sequences encoding ‘novel’ Anisakis allergenic proteins (i.e. cyclophilins and ABA-1 domain containing proteins). Conclusions/Significance This study represents a first step towards providing the research community with a curated dataset to use as a molecular resource for future investigations of the biology of Anisakis, including molecules putatively acting as allergens, using functional genomics, proteomics and immunological tools. Ultimately, an improved knowledge of the biological functions of these molecules in the parasite, as well as of their immunogenic properties, will assist the development of comprehensive, reliable and robust diagnostic tools. PMID:27472517

  16. Fundamental basis and implementation of shell and tube heat exchanger project design: condenser and evaporator study

    NASA Astrophysics Data System (ADS)

    Dalkilic, A. S.; Acikgoz, O.; Tapan, S.; Wongwises, S.

    2016-03-01

    A shell and tube heat exchanger is used as a condenser and an evaporator in this theoretical study. Parametric performance analyses for various actual refrigerants were performed using well-known correlations in open sources. Condensation and evaporation were occurred in the shell side while the water was flowing in the tube side of heat exchanger. Heat transfer rate from tube side was kept constant for condenser and evaporator design. Condensing temperatures were varied from 35 to 60 °C whereas evaporating temperatures were ranging from -15 to 10 °C for the refrigerants of R12, R22, R134a, R32, R507A, R404A, R502, R407C, R152A, R410A and R1234ZE. Variation of convective heat transfer coefficients of refrigerants, total heat transfer coefficients with Reynolds numbers and saturation temperatures were given as validation process considering not only fouling resistance and omission of it but also staggered (triangular) and line (square) arrangements. The minimum tube lengths and necessary pumping powers were calculated and given as case studies for the investigated refrigerants considering validation criteria. It was understood that refrigerant type, fouling resistance and arrangement type are one of the crucial issues regarding the determination of heat exchanger's size and energy consumption. Consequently, R32 and R152a were found to require the shortest tube length and lowest pumping power in the condenser, whereas R507 and R407C have the same advantages in the evaporator. Their heat transfer coefficients were also determined larger than others as expectedly.

  17. Fundamental Study on Localized Heating in Hyperthermia Using Phase Control of Long-wavelength Microwaves

    NASA Astrophysics Data System (ADS)

    Matsumoto, Hiroshi; Ishida, Hiroki; Nakamoto, Satoshi; Takeno, Hiromasa; Yasaka, Yasuyoshi; Kawai, Shigeaki; Mitani, Tomohiko; Shinohara, Naoki; Namiki, Hironori

    For the treatment of cancer using hyperthermia, high frequency electromagnetic fields are used to heat the cancer cells. These electromagnetic fields fall into two general frequency ranges, one relatively low, and the other in the microwave range. Both produce some side effects such as the heating of healthy cells or the impact on the body of invasive surgery required to expose deep-lying cells. To reduce these side reactions, the use of lower microwave frequencies with phase control was proposed. In this paper, we present a very basic study to prove the viability of the proposed scheme. This includes the selection of a suitable frequency, demonstration of localized heating using the selected frequency, and a three-dimensional numerical analysis of the electromagnetic fields involved. In the heating demonstration, a tissue-equivalent phantom made from agar was irradiated by phase-controlled electromagnetic waves from a pair of circular patch antennas operating at 430MHz. This produced localized heating. The numerical analysis produced a field distribution that corresponded closely to the results from the heating experiment. It confirmed that the phase control technique for long-wavelength microwaves was effective in producing localized heating.

  18. Nucifer: A small electron-antineutrino detector for fundamental and safeguard studies

    SciTech Connect

    Letourneau, A.; Bui, V. M.; Fallot, M.; Giot, L.; Martino, J.; Porta, A.; Varignon, C.; Yermia, F.

    2011-07-01

    The Nucifer detector will be deployed in the next few months at the Osiris research reactor in France. Nucifer is a 1-ton Gd-doped liquid scintillator detector devoted to reactor antineutrino studies. It will be installed 7 m away from the compact core of the Osiris reactor. The design of such small volume detector has been focused on high detection efficiency and good background rejection. Over the last decades, our understanding of the neutrino properties has been improved and allows today the possibility to apply the detection of antineutrinos to automatic and to non intrusively survey nuclear power plant. This has triggered the interest of the International Atomic Energy Agency (IAEA), which is interested by developing new safeguard techniques for next generation reactors. The sensitivity of such technique has to be proved and demonstrated. On the other hand there is still some issues in our understanding of the neutrino properties as the observed deficit in the antineutrino rate at short distances (< 100 m) that can not be explained by oscillations in the 3-flavors neutrino model. If a global systematic error is rejected, such anomaly opens the door to new physic that can be assessed with small detectors placed close to the core. Here we review the Nucifer detector in this context and the tests we are performing. (authors)

  19. [Fundamental study on effect of high-mineral drinking water for osteogenesis in calciprivia ovariectomized rats].

    PubMed

    Ogata, Fumihiko; Nagai, Noriaki; Ito, Yoshimasa; Kawasaki, Naohito

    2014-01-01

    Since osteoporosis is a major public health problem in Japan, it is important to clarify the effect of high-mineral drinking water consumption on osteogenesis. Therefore, in this study, we investigated the relationship between high-mineral drinking water consumption and osteogenesis in ovariectomized rats that received a low-calcium diet and purified water (PW group) or a low-calcium diet and high-mineral drinking water (CR group). High-mineral drinking water affected the rats' body weight. After 3 months, the bone density of the CR group was higher than that of the PW group (p<0.05). Furthermore, the CR group showed a decrease in the amount of calcium in the bones after 3 months. These results suggest that high-mineral drinking water contributes to the maintenance of bone density and not to the amount of calcium in bone. On the other hand, serum alkaline phosphatase levels in the PW group at 3 months were higher than those in the CR group, which indicates that the blood concentration of calcium in the CR group was maintained. Moreover, the amount of magnesium in the bones and the blood concentration of magnesium in the CR group after 3 months were higher than the corresponding values in the PW group. These results suggest that consumption of high-mineral drinking water could be beneficial for osteogenesis (i.e., for maintaining bone quantity).

  20. Fundamental study of spin-coating using in-situ analysis and simulation

    NASA Astrophysics Data System (ADS)

    Harumoto, Masahiko; Yoshida, Jun-ichi; Stokes, Harold; Tanaka, Yuji; Miyagi, Tadashi; Kaneyama, Koji; Pieczulewski, Charles; Asai, Masaya

    2015-03-01

    Spin coating has been used as a photoresist application method for many years, and consequently certain defects have been recognized through each resist generation; i-line, KrF, ArF, ArF immersion and, most recently, EUV. Last year we reported an in-situ analysis via high-speed video camera that proved to be useful for understanding defect formation such as non-uniformity spots within organic film coatings and post-develop water-mark defects. In this study, fingerprints known as `tiger stripes' around the wafer's edge were analyzed. This phenomenon, for example, is directly related to the wafer spin-speed and air-flow during the coat-processing. Utilizing a high-speed camera and 3D simulation, we reveal the mechanism of fingerprint generation for tiger stripe phenomena, confirm the mechanism with several different spin-speeds, and correlate these to defect inspection results. Furthermore, we will discuss the expansion to 450mmm wafers.

  1. Fundamental studies of hydrogen chemisorption on supported monometallic and bimetallic catalysts using microcalorimetry

    SciTech Connect

    Narayan, R.L.

    1997-06-24

    Highly dispersed transition metal catalysts are used in numerous commercial processes such as hydrocarbon conversions. For example, the use of Pt supported on acidic alumina or silica-alumina for reforming of naphtha in the production of gasoline is well known. Another use of supported catalysts is in automobile emission control where supported Pt-Rh bimetallic catalysts are used. Supported Ru can be used in Fischer-Tropsch synthesis for the production of higher hydrocarbons from synthesis gas. While many of these catalyst systems have been in commercial operation for several decades there is still a lack of consensus regarding the exact role of the catalyst on a molecular level. In particular, little is known about the mechanisms operating on the catalyst surface at the high pressure and high temperature conditions typically used in commercial operations. This report contains the general introduction and conclusions and an appendix containing the operating instructions for a microcalorimeter. Three chapters have been processed separately. They are: the effect of K on the kinetics and thermodynamics of hydrogen adsorption on Ru/SiO{sub 2}; hydrogen adsorption states on silica supported Ru-Ag and Ru-Cu bimetallic catalysts investigated via microcalorimetry; a comparative study of hydrogen chemisorption on silica supported Ru, Rh, and Pt.

  2. Does planetary temperature fundamentally affect water availability on land? An idealized modeling study

    NASA Astrophysics Data System (ADS)

    Scheff, J.; Frierson, D. M.

    2013-12-01

    The geologic and paleobotanical record is usually said to show that during warm greenhouse climates of Earth's past, moisture for plant growth was at least as plentiful as it is today in most land areas. Similarly, very cold glacial stages are usually interpreted as times of water scarcity, outside of a few small regions. Yet, for the warm greenhouse climates of Earth's near future, comprehensive models largely project declines in time-mean soil moisture, and increases in physical drought and aridity measures. This study attempts to understand these projections by using a simple, general, idealized land model coupled to a global atmosphere model (GFDL AM2.1) and a slab ocean. The model is run to equilibrium over a wide range of planetary temperatures, and the responses of land hydroclimates are examined. In particular, several different dimensionless water-scarcity metrics are tracked, including near-surface relative humidity, ratios between precipitation, actual and potential evapotranspiration, and the percent of maximum soil moisture. These experiments are performed for a very wide range of land model parameters, atmospheric parameterizations, idealized continent geometries, prescribed ocean heat transport fields, astronomical boundary conditions, and temperature change mechanisms. If dimensionless water availability systematically declines with increasing planetary temperature regardless of these choices, then the model result might be viewed as robust. However, if certain modeling choices, metrics, and/or regions indicate the opposite behavior, in line with the geologic record, then the results could greatly aid in the interpretation of that record.

  3. A further Rasch study confirms that ALSFRS-R does not conform to fundamental measurement requirements.

    PubMed

    Franchignoni, Franco; Mandrioli, Jessica; Giordano, Andrea; Ferro, Salvatore

    2015-01-01

    Our objective was to verify and expand previous evidence of psychometric inadequacies in the ALSFRS-R, in a different sample of subjects suffering from ALS. Since 2009, a prospective registry records all incident cases of ALS in Emilia Romagna Region, Italy (4.4 million inhabitants) referred to its 17 neurological departments. For each patient, demographic and clinical information is collected by the physician in charge, including compilation of the ALSFRS-R at each clinical follow-up. Results showed that a confirmatory factor analysis on the three-factor model previously found (bulbar, motor, respiratory function) showed a good fit. Rasch analysis on the whole scale showed the need to collapse some rating categories, confirmed the multidimensionality of the ALSFRS-R, and demonstrated the presence of differential item functioning between patients with spinal versus bulbar onset. Moreover, some items included in the three ALSFRS-R subscales showed a problematic fit to the respective construct they were intended to measure. In conclusion, the interpretation of a total raw score of ALSFRS-R is hampered by ambiguities due to the different metric properties of the three domains the scale aggregates, and their content and structure. This study confirms that a refinement of ALSFRS-R is warranted, pointing to the need to revise its whole structure, and providing detailed guidelines for its revision.

  4. Fundamental study on magnetic separation of aquatic organisms for preservation of marine ecosystem

    NASA Astrophysics Data System (ADS)

    Sakaguchi, F.; Akiyama, Y.; Izumi, Y.; Nishijima, S.

    2009-10-01

    Recently, destruction and disturbance of marine ecosystem have been caused by changes in global environment and transplants of farmed fishes and shellfishes. To solve the problems, water treatment techniques to kill or to remove aquatic organisms are necessary. In this study, application of magnetic separation for removal of the aquatic organisms was examined in order to establish the process with high-speed, compact device and low environmental load. Techniques of magnetic seeding and magnetic separation using superconducting magnet are important for high-speed processing of aquatic organisms. Magnetic seeding is to adhere separating object to the surface of ferromagnetic particles, and magnetic separation is to remove aquatic organisms with magnetic force. First, we confirmed the possibility of magnetic seeding of aquatic organisms, and then interaction between aquatic organisms and ferromagnetic particles was examined. Next, for practical application of magnetic separation system using superconducting magnet for removal of aquatic organisms, particle trajectories were simulated and magnetic separation experiment using superconducting magnet was performed in order to design magnetic separation system to achieve high separation efficiency.

  5. FUNDAMENTAL STUDIES OF THE DURABILITY OF MATERIALS FOR INTERCONNECTS IN SOLID OXIDE FUEL CELLS

    SciTech Connect

    Frederick S. Pettit; Gerald H. Meier

    2003-06-30

    This report describes the result of the first eight months of effort on a project directed at improving metallic interconnect materials for solid oxide fuel cells (SOFCs). The results include cyclic oxidation studies of a group of ferritic alloys, which are candidate interconnect materials. The exposures have been carried out in simulated fuel cell atmospheres. The oxidation morphologies have been characterized and the ASR has been measured for the oxide scales. The effect of fuel cell electric current density on chromia growth rates has been considered The thermomechanical behavior of the scales has been investigated by stress measurements using x-ray diffraction and interfacial fracture toughness measurements using indentation. The ultimate goal of this thrust is to use knowledge of changes in oxide thickness, stress and adhesion to develop accelerated testing methods for evaluating SOFC interconnect alloys. Finally a theoretical assessment of the potential for use of ''new'' metallic materials as interconnect materials has been conducted and is presented in this report. Alloys being considered include materials based on pure nickel, materials based on the ''Invar'' concept, and coated materials to optimize properties in both the anode and cathode gases.

  6. A fundamental study on hyper-thermal neutrons for neutron capture therapy.

    PubMed

    Sakurai, Y; Kobayashi, T; Kanda, K

    1994-12-01

    The utilization of hyper-thermal neutrons, which have an energy spectrum with a Maxwellian distribution at a higher temperature than room temperature (300 K), was studied in order to improve the thermal neutron flux distribution at depth in a living body for neutron capture therapy. Simulation calculations were carried out using a Monte Carlo code 'MCNP-V3' in order to investigate the characteristics of hyper-thermal neutrons, i.e. (i) depth dependence of the neutron energy spectrum, and (ii) depth distribution of the reaction rate in a water phantom for materials with 1/v neutron absorption. It is confirmed that hyper-thermal neutron irradiation can improve the thermal neutron flux distribution in the deeper areas in a living body compared with thermal neutron irradiation. When hyper-thermal neutrons with a 3000 K Maxwellian distribution are incident on a body, the reaction rates of 1/v materials such as 14N, 10B etc are about twice that observed for incident thermal neutrons at 300 K, at a depth of 5 cm. The limit of the treatable depth for tumours having 30 ppm 10B is expected to be about 1.5 cm greater by utilizing hyper-thermal neutrons at 3000 K compared with the incidence of thermal neutrons at 300 K.

  7. Fundamental study on dissolution behavior of poly(methyl methacrylate) by quartz crystal microbalance

    NASA Astrophysics Data System (ADS)

    Konda, Akihiro; Yamamoto, Hiroki; Yoshitake, Shusuke; Kozawa, Takahiro

    2016-03-01

    Ionizing radiations such as extreme ultraviolet (EUV) and electron beam (EB) are the most promising exposure source for next-generation lithographic technology. In the realization of high resolution lithography, it is necessary for resist materials to improve the trade-off relationship among sensitivity, resolution, and line width roughness (LWR). In order to overcome them, it is essential to understand basic chemistry of resist matrices in resist processes. In particular, the dissolution process of resist materials is a key process. Therefore, it is essential for next-generation resist design for ionizing radiation to clarify the dissolution behavior of the resist film into developer. However, the details in dissolution process of EUV and EB resist films have not been investigated thus far. In this study, main chain scission and dissolution behavior of poly(methyl methacrylate) (PMMA) as main chain scission type resist was investigated using quartz crystal microbalance (QCM) method and gel permeation chromatography (GPC) in order to understand the relationship between the degree of PMMA degradation and dissolution behavior. The relationship between the molecular weight after irradiation and the swelling behavior was clarified.

  8. Fundamental studies of coal liquefaction. Quarterly report No. 5, October 1, 1992--January 1, 1993

    SciTech Connect

    Ross, D.S.

    1993-02-04

    The results for the control run for a single particle are shown in Figure 1. The figure, which includes other thermolytic data for Illinois No. 6 coal, shows that the particle was stable in size to around 440{degree}C. At that point it contracted very rapidly to about half its size over the next 15{degrees}. Also shown are data for the same coal from SRI`s field ionization mass spectrometer (FIMS), in which case a sample of the coal is heated at 2.5{degrees}C/min from ambient to 500{degrees}C and the effluent is swept into mass spectrometer. The evolution of the coal volatiles is reflected by accumulated ion count with increasing temperature, and is presented in the figure as the fraction of total volatiles. As the figure shows, the abrupt increase in volatility corresponds very closely to the equally abrupt reduction in particle size. The weight average molecular weight profile from the FIMS work is also in the figure, and shows that the coal experiences a simple loss of volatiles of increasing molecular weight up to around 440{degrees}C. At that point pyrolysis and fragmentation come about, reflected in the quick reversal and decline in molecular weight. The high rate of volatility and shrinkage are clearly associated with this second stage in the pyrolytic process. These results are further in line with the account of Eser et al. (1991) who found in studies of Illinois No. 6 coal in a high pressure microdilatometer that the coal contracted by about 40% in the same region of temperature at heating rates of around 20{degrees}C/min. At higher heating rates the contraction was followed by a swelling. Finally, in our cell work we observed the deposition of tar in the diamond windows starting at around 350{degrees}C.

  9. Fundamental studies of coal liquefaction. Quarterly report No. 7, April 1--July 1, 1993

    SciTech Connect

    Ross, D.S.

    1993-07-14

    In our last report we discussed observations in our cell concerning the behavior or Illinois No. 6 coal in tetralin to 460{degrees}C. We noted that there were possibly two distinct types of particles comprising the organic phase, reacting respectively at 420{degrees}--430{degrees}C, and at 450{degrees}--460{degrees}C. Alternatively we could interpret the data as describing a range of reactivity bounded by those temperatures. As evidenced by the contraction of the particles, the reactions were rapid. The particles lost half of their substance within 1 min, and we suggested that the rates were too fast to be accommodated by the commonly held scheme for coal liquefaction involving thermolytic scission of weak, bibenzyl-like bonds. Our analyses were aided by our use of Adobe Photoshop, which allows us to store, digitized versions of our recorded images. The images can then be manipulated at will to provide quantitative data on morphological changes. We noted in our last report that printer limitations prevented us from presenting images with the desirable quality, and we are at present attempting to find access to equipment which will provide satisfactory figures. Accordingly our progress will be described here without any photographs, and we expect to present a more complete account of our work in our next report. The work reported here includes studies of Illinois No. 6 coal with water as the medium, and a control run with argon as medium. Our temperature ramping was like that used last time, 25{degrees}C/min to 250{degrees}C, and then 10{degrees}C/min to 450{degrees}C. The results from the earlier work and the data presented here can therefore be directly compared.

  10. Radiolytic Modification of Sulfur Containing Acidic Amino Residues in Model Peptides: Fundamental Studies for Protein Footprinting

    SciTech Connect

    Xu,G.; Chance, M.

    2005-01-01

    Protein footprinting based on hydroxyl radical-mediated modification and quantitative mass spectroscopic analysis is a proven technique for examining protein structure, protein-ligand interactions, and structural allostery upon protein complex formation. The reactive and solvent-accessible amino acid side chains function as structural probes; however, correct structural analysis depends on the identification and quantification of all the relevant oxidative modifications within the protein sequence. Sulfur-containing amino acids are oxidized readily and the mechanisms of oxidation are particularly complex, although they have been extensively investigated by EPR and other spectroscopic methods. Here we have undertaken a detailed mass spectrometry study (using electrospray ionization mass spectrometry and tandem mass spectrometry) of model peptides containing cysteine (Cys-SH), cystine (disulfide bonded Cys), and methionine after oxidation using {gamma}-rays or synchrotron X-rays and have compared these results to those expected from oxidation mechanisms proposed in the literature. Radiolysis of cysteine leads to cysteine sulfonic acid (+48 Da mass shift) and cystine as the major products; other minor products including cysteine sulfinic acid (+32 Da mass shift) and serine (-16 Da mass shift) are observed. Radiolysis of cystine results in the oxidative opening of the disulfide bond and generation of cysteine sulfonic acid and sulfinic acid; however, the rate of oxidation is significantly less than that for cysteine. Radiolysis of methionine gives rise primarily to methionine sulfoxide (+16 Da mass shift); this can be further oxidized to methionine sulfone (+32 Da mass shift) or another product with a -32 Da mass shift likely due to aldehyde formation at the {gamma}-carbon. Due to the high reactivity of sulfur-containing amino acids, the extent of oxidation is easily influenced by secondary oxidation events or the presence of redox reagents used in standard proteolytic

  11. A fundamental study on biological removal of N2O in the presence of oxygen.

    PubMed

    Figueroa-González, Ivonne; Quijano, Guillermo; Laguna, Inés; Muñoz, Raúl; García-Encina, Pedro A

    2016-09-01

    The biodegradation of N2O by a non-acclimated secondary activated sludge in the presence of O2 was studied. Batch tests with a headspace containing an initial N2O concentration of ∼400 mg m(-3) (∼200 ppmv) and initial O2 gas concentrations of 0%, 1%, 2%, 5% and 21% were investigated. The effect of O2 on the biokinetic parameters qmax (maximum specific N2O uptake rate) and KS (half-saturation constant), as well as on the bacterial population structure, was evaluated. A complete N2O removal was recorded in the presence of up to 2% O2, while O2 at 5% and 21% mediated inhibitions of 37% and 95% in the removal of N2O compared with the control without O2. The elemental analysis of the biomass obtained at the end of the batch tests strongly suggested that NN2O was not used as a nitrogen source. The presence of O2 mediated decreases of up to 12.6- and 4.8-fold in qmax and KS, respectively, compared to the control without O2. Likewise, the presence of O2 induced changes in the structure of the bacterial population. The predominant microorganisms in the presence of O2 belonged to the phyla Proteobacteria, Firmicutes and Chlamydiae. Bacteria belonging to the Proteobacteria phylum, particularly the Dokdonella genus, were predominant at 2% O2, which was the highest O2 concentration without inhibitory effects on N2O biodegradation. PMID:27236493

  12. Fundamental studies on kinetic isotope effect (KIE) of hydrogen isotope fractionation in natural gas systems

    USGS Publications Warehouse

    Ni, Y.; Ma, Q.; Ellis, G.S.; Dai, J.; Katz, B.; Zhang, S.; Tang, Y.

    2011-01-01

    Based on quantum chemistry calculations for normal octane homolytic cracking, a kinetic hydrogen isotope fractionation model for methane, ethane, and propane formation is proposed. The activation energy differences between D-substitute and non-substituted methane, ethane, and propane are 318.6, 281.7, and 280.2cal/mol, respectively. In order to determine the effect of the entropy contribution for hydrogen isotopic substitution, a transition state for ethane bond rupture was determined based on density function theory (DFT) calculations. The kinetic isotope effect (KIE) associated with bond rupture in D and H substituted ethane results in a frequency factor ratio of 1.07. Based on the proposed mathematical model of hydrogen isotope fractionation, one can potentially quantify natural gas thermal maturity from measured hydrogen isotope values. Calculated gas maturity values determined by the proposed mathematical model using ??D values in ethane from several basins in the world are in close agreement with similar predictions based on the ??13C composition of ethane. However, gas maturity values calculated from field data of methane and propane using both hydrogen and carbon kinetic isotopic models do not agree as closely. It is possible that ??D values in methane may be affected by microbial mixing and that propane values might be more susceptible to hydrogen exchange with water or to analytical errors. Although the model used in this study is quite preliminary, the results demonstrate that kinetic isotope fractionation effects in hydrogen may be useful in quantitative models of natural gas generation, and that ??D values in ethane might be more suitable for modeling than comparable values in methane and propane. ?? 2011 Elsevier Ltd.

  13. A Fundamental Study of Nucleate Pool Boiling Under Microgravity. Final report

    SciTech Connect

    Ervin, J.S.; Merte, H. Jr.

    1996-03-01

    An experimental study of incipient boiling in short-term microgravity and with a/g = {+-} 1 for pool boiling was performed. Calibrated thin gold films sputtered on a smoothly polished quartz surface were used simultaneously for thermal-resistance measurements and heating of the boiling surface. The gold films were used for both transient and quasi-steady heating surface temperature measurements. Two test vessels were constructed for precise measurement and control of fluid temperature and pressure: a laboratory pool boiling vessel for the a/g = {+-} 1 experiments and a pool boiling vessel designed for the 131 m free-fall in the NASA Lewis Research Center Microgravity Research Facility for the microgravity tests. Measurements included the heater surface temperature, the pressure near the heating surface, the bulk liquid temperatures. High speed photography (up to 1,000 frames per second) was used in the experiments. With high quality microgravity and the measured initial temperature of the quiescent test fluid, R113, the temperature distribution in the liquid at the moment of boiling inception resulting from an imposed step in heat flux is known with a certainty not possible previously. The types of boiling propagation across the large flat heating surface, some observed here for the first time, are categorized; the conditions necessary for their occurrence are described. Explosive boiling propagation with a striking pattern of small scale protuberances over the entire vapor mass periphery not observed previously at low heat flux levels (on the order of 5 W/cm(exp 2)) is described. For the heater surface with a/g = {minus}1, a step in the heater surface temperature of short duration was imposed. The resulting liquid temperature distribution at the moment of boiling inception was different from that obtained with a step in heat flux.

  14. Testing Our Fundamental Assumptions

    NASA Astrophysics Data System (ADS)

    Kohler, Susanna

    2016-06-01

    fundamental assumptions.A recent focus set in the Astrophysical Journal Letters, titled Focus on Exploring Fundamental Physics with Extragalactic Transients, consists of multiple published studies doing just that.Testing General RelativitySeveral of the articles focus on the 4th point above. By assuming that the delay in photon arrival times is only due to the gravitational potential of the Milky Way, these studies set constraints on the deviation of our galaxys gravitational potential from what GR would predict. The study by He Gao et al. uses the different photon arrival times from gamma-ray bursts to set constraints at eVGeV energies, and the study by Jun-Jie Wei et al. complements this by setting constraints at keV-TeV energies using photons from high-energy blazar emission.Photons or neutrinos from different extragalactic transients each set different upper limits on delta gamma, the post-Newtonian parameter, vs. particle energy or frequency. This is a test of Einsteins equivalence principle: if the principle is correct, delta gamma would be exactly zero, meaning that photons of different energies move at the same velocity through a vacuum. [Tingay Kaplan 2016]S.J. Tingay D.L. Kaplan make the case that measuring the time delay of photons from fast radio bursts (FRBs; transient radio pulses that last only a few milliseconds) will provide even tighter constraints if we are able to accurately determine distances to these FRBs.And Adi Musser argues that the large-scale structure of the universe plays an even greater role than the Milky Way gravitational potential, allowing for even stricter testing of Einsteins equivalence principle.The ever-narrower constraints from these studies all support GR as a correct set of rules through which to interpret our universe.Other Tests of Fundamental PhysicsIn addition to the above tests, Xue-Feng Wu et al. show that FRBs can be used to provide severe constraints on the rest mass of the photon, and S. Croft et al. even touches on what we

  15. Fundamentals studies in geodynamics

    NASA Technical Reports Server (NTRS)

    Anderson, D. L.

    1980-01-01

    Research in geodynamics, seismology, and planetary quakes is presented. Terradynamics and plate tectonics are described using dynamic models. The early evolution of the Earth's mantle is also discussed.

  16. Fundamental studies in the molecular basis of laser-induced retinal damage. Annual report, February-September 1981

    SciTech Connect

    Lewis

    1981-09-01

    Laser-spectroscopy experiments have focused on cones in the red-eared swamp turtle, Pseudemys scripta elegans. Choice of this system was based on the desire to correlate molecular data with the extensive data being collected on this system by Dr. Zwick in his studies on laser hazards at LAIR. Thus, a detailed collaborative effort was initiated on this system during the past year. The experiments resulted in important information that opens new avenues to explore fundamental molecular mechanisms of retinal damage with laser irradiation. Results of these experiments are summarized in the following sections: I. Elucidation of the role of oil droplets in the absorption of light by the turtle retina; II. A Selective Probe of Membrane Potentials in Turtle Cone Cells; III. Angstrom Resolution Light Microscopy of Photoreceptor Cells; IV. Identification and Selective Staining of Other Important Molecular Components of Photoreceptor Cells.

  17. Hypotheses and fundamental study design characteristics for evaluating potential reduced-risk tobacco products. Part I: Heuristic.

    PubMed

    Murrelle, Lenn; Coggins, Christopher R E; Gennings, Chris; Carchman, Richard A; Carter, Walter H; Davies, Bruce D; Krauss, Marc R; Lee, Peter N; Schleef, Raymond R; Zedler, Barbara K; Heidbreder, Christian

    2010-06-01

    The risk-reducing effect of a potential reduced-risk tobacco product (PRRP) can be investigated conceptually in a long-term, prospective study of disease risks among cigarette smokers who switch to a PRRP and in appropriate comparison groups. Our objective was to provide guidance for establishing the fundamental design characteristics of a study intended to (1) determine if switching to a PRRP reduces the risk of lung cancer (LC) compared with continued cigarette smoking, and (2) compare, using a non-inferiority approach, the reduction in LC risk among smokers who switched to a PRRP to the reduction in risk among smokers who quit smoking entirely. Using standard statistical methods applied to published data on LC incidence after smoking cessation, we show that the sample size and duration required for a study designed to evaluate the potential for LC risk reduction for an already marketed PRRP, compared with continued smoking, varies depending on the LC risk-reducing effectiveness of the PRRP, from a 5-year study with 8000-30,000 subjects to a 15-year study with <5000 to 10,000 subjects. To assess non-inferiority to quitting, the required sample size tends to be about 10 times greater, again depending on the effectiveness of the PRRP.

  18. SISGR-Fundamental Experimental and Theoretical Studies on a Novel Family of Oxide Catalyst Supports for Water Electrolysis

    SciTech Connect

    Kumta, Prashant

    2014-10-03

    Identification and development of non-noble metal based electro-catalysts or electro-catalysts with significant reduction of expensive noble metal contents (E.g. IrO2, Pt) with comparable electrochemical performance as the standard noble metal/metal oxide for proton exchange membrane (PEM) based water electrolysis would constitute a major breakthrough in the generation of hydrogen by water electrolysis. Accomplishing such a system would not only result reduction of the overall capital costs of PEM based water electrolyzers, but also help attain the targeted hydrogen production cost [< $ 3.0 / gallon gasoline equivalent (gge)] comparable to conventional liquid fuels. In line with these goals, it was demonstrated that fluorine doped IrO2 thin films and nanostructured high surface area powders display remarkably higher electrochemical activity, and comparable durability as pure IrO2 electro-catalyst for the oxygen evolution reaction (OER) in PEM based water electrolysis. Furthermore, corrosion resistant SnO2 and NbO2 support has been doped with F and coupled with IrO2 or RuO2 for use as an OER electro-catalyst. A solid solution of SnO2:F or NbO2:F with only 20 - 30 mol.% IrO2 or RuO2 yielding a rutile structure in the form of thin films and bulk nanoparticles displays similar electrochemical activity and stability as pure IrO2/RuO2. This would lead to more than 70 mol.% reduction in the noble metal oxide content. Novel nanostructured ternary (Ir,Sn,Nb)O2 thin films of different compositions FUNDAMENTAL STUDY OF NANOSTRUCTURED ELECTRO-CATALYSTS WITH REDUCED NOBLE METAL CONTENT FOR PEM BASED WATER ELECTROLYSIS 4 have also been studied. It has been shown that (Ir0.40Sn0.30Nb0.30)O2 shows similar electrochemical activity and enhanced chemical robustness as compared to pure IrO2. F doping of the ternary (Ir,Sn,Nb)O2 catalyst helps in further decreasing the noble metal oxide content of the catalyst. As a result, these reduced noble metal oxide catalyst systems would

  19. Fundamental Study on Saving Energy for Electrified Railway System Applying High Temperature Superconductor Motor and Energy Storage System

    NASA Astrophysics Data System (ADS)

    Konishi, Takeshi; Nakamura, Taketsune; Amemiya, Naoyuki

    Induction motor instead of dc one has been applied widely for dc electric rolling stock because of the advantage of its utility and efficiency. However, further improvement of motor characteristics will be required to realize environment-friendly dc railway system in the future. It is important to study more efficient machine applying dc electric rolling stock for next generation high performance system. On the other hand, the methods to reuse regenerative energy produced by motors effectively are also important. Therefore, we carried out fundamental study on saving energy for electrified railway system. For the first step, we introduced the energy storage system applying electric double-layer capacitors (EDLC), and its control system. And then, we tried to obtain the specification of high temperature superconductor induction/synchronous motor (HTS-ISM), which performance is similar with that of the conventional induction motors. Furthermore, we tried to evaluate an electrified railway system applying energy storage system and HTS-ISM based on simulation. We succeeded in showing the effectiveness of the introductions of energy storage system and HTS-ISM in DC electrified railway system.

  20. Fundamental studies with a monodisperse aerosol-based liquid chromatography/mass spectrometry interface (MAGIC-LC/MS)

    SciTech Connect

    Browner, R.F.

    1990-10-01

    Accomplishments on the fundamental studies with a monodisperse aerosol-based liquid chromatography/mass spectrometry (LC/MS) interface during the period 1 December 1989 to 30 November 1990 are summarized. In order to determine the influence of temperature on the vaporization and decomposition properties of molecules, test have been carried out on both thermally stable and thermally labile molecules. The test compounds used were a series of polynuclear aromatic (PAH) compounds covering a wide range of molecular weights from two-ring naphthalene to twelve-ring perylene. The less thermally stable species examined were aldicarb, a highly thermally labile pesticide, and cholesterol, which readily loses water when subjected to high temperatures. A new, externally heated probe, which can be raised to temperatures as high as 500{degree}C was also used. Matrix loading effects for a range of surface active and non-surface active compounds in three different matrices: glycerol, 3-nitrobenzyl alcohol, and thioglycerol for fast atom bombardment (FAB) particle beam LC/MS have been studied. The time dependence of FAB spectra generation in the particle beam system has been examined and contrasted with ion generation in normal probe FAB work. Future FAB LC/MS research is outlined. 3 refs. (BM)

  1. Fundamental studies on initiation and evolution of multi-channel discharges and their application to next generation pulsed power machines.

    SciTech Connect

    Schwarz, Jens; Savage, Mark E.; Lucero, Diego Jose; Jaramillo, Deanna M.; Seals, Kelly Gene; Pitts, Todd Alan; Hautzenroeder, Brenna M.; Laine, Mark Richard; Karelitz, David B.; Porter, John L.

    2014-09-01

    Future pulsed power systems may rely on linear transformer driver (LTD) technology. The LTD's will be the building blocks for a driver that can deliver higher current than the Z-Machine. The LTD's would require tens of thousands of low inductance ( %3C 85nH), high voltage (200 kV DC) switches with high reliability and long lifetime ( 10 4 shots). Sandia's Z-Machine employs 36 megavolt class switches that are laser triggered by a single channel discharge. This is feasible for tens of switches but the high inductance and short switch life- time associated with the single channel discharge are undesirable for future machines. Thus the fundamental problem is how to lower inductance and losses while increasing switch life- time and reliability. These goals can be achieved by increasing the number of current-carrying channels. The rail gap switch is ideal for this purpose. Although those switches have been extensively studied during the past decades, each effort has only characterized a particular switch. There is no comprehensive understanding of the underlying physics that would allow predictive capability for arbitrary switch geometry. We have studied rail gap switches via an extensive suite of advanced diagnostics in synergy with theoretical physics and advanced modeling capability. Design and topology of multichannel switches as they relate to discharge dynamics are investigated. This involves electrically and optically triggered rail gaps, as well as discrete multi-site switch concepts.

  2. Exploiting the Temperature/Concentration Dependence of Magnetic Susceptibility to Control Convection in Fundamental Studies of Solidification Phenomena

    NASA Technical Reports Server (NTRS)

    Evans, J. W.; Xu, Dong; Jones, W. Kinzy, Jr.; Szofran, Frank R.

    1999-01-01

    The objective of this new research project is to demonstrate by experiment, supplemented by mathematical modeling and physical property measurement, that the effects of buoyancy driven convection can be largely eliminated in ground-based experiments, and further reduced in flight, by applying a new technique. That technique exploits the dependence of magnetic susceptibility on composition or temperature. It is emphasized at the outset that the phenomenon to be exploited is fundamentally and practically different from the magnetic damping of convection in conducting liquids that has been the subject of much prior research. The concept suggesting this research is that all materials, even non-conductors, when placed in a magnetic field gradient, experience a force. Of particular interest here are paramagnetic and diamagnetic materials, classes which embrace the "model alloys", such as succinonitrile-acetone, that have been used by others investigating the fundamentals of solidification. Such alloys will exhibit a dependence of susceptibility on composition. The consequence is that, with a properly oriented field (gradient) a force will arise that can be made to be equal to, but opposite, the buoyancy force arising from concentration (or temperature) gradients. In this way convection can be stilled. The role of convection in determining the microstructure, and thereby properties, of materials is well known. Elimination of that convection has both scientific and technological consequences. Our knowledge of diffusive phenomena in solidification, phenomena normally hidden by the dominance of convection, is enhanced if we can study solidification of quiescent liquids. Furthermore, the microstructure, microchemistry and properties of materials (thereby practical value) are affected by the convection occurring during their solidification. Hitherto the method of choice for elimination of convection has been experimentation in microgravity. However, even in low Earth orbit

  3. Fundamental Studies and Development of III-N Visible LEDs for High-Power Solid-State Lighting Applications

    SciTech Connect

    Dupuis, Russell

    2012-02-29

    The goal of this program is to understand in a fundamental way the impact of strain, defects, polarization, and Stokes loss in relation to unique device structures upon the internal quantum efficiency (IQE) and efficiency droop (ED) of III-nitride (III-N) light-emitting diodes (LEDs) and to employ this understanding in the design and growth of high-efficiency LEDs capable of highly-reliable, high-current, high-power operation. This knowledge will be the basis for our advanced device epitaxial designs that lead to improved device performance. The primary approach we will employ is to exploit new scientific and engineering knowledge generated through the application of a set of unique advanced growth and characterization tools to develop new concepts in strain-, polarization-, and carrier dynamics-engineered and low-defect materials and device designs having reduced dislocations and improved carrier collection followed by efficient photon generation. We studied the effects of crystalline defect, polarizations, hole transport, electron-spillover, electron blocking layer, underlying layer below the multiplequantum- well active region, and developed high-efficiency and efficiency-droop-mitigated blue LEDs with a new LED epitaxial structures. We believe new LEDs developed in this program will make a breakthrough in the development of high-efficiency high-power visible III-N LEDs from violet to green spectral region.

  4. Fundamental studies in the molecular basis of laser-induced retinal damage. Annual report, September 1983-September 1984

    SciTech Connect

    Lewis, A.

    1984-09-01

    Advances made in the work for the Ocular Hazards Program at the Letterman Army Institute of Research (LAIR) are described. The research has seen the first application of femtosecond lasers to the visual system; it is giving new insights into how these ultimate laser sources interact with biological tissue in general and with the visual system in particular. The authors have discovered that simple anions can activate visual photoreceptors in the dark; among these anionic activators is the dental agent fluoride. Research has continued into identifying selectively and spatially the image of various elements in photoreceptors and adjacent tissue. The authors were able to extend our preparation procedures to view the elemental composition of such components as melanin granules. The sensitive and selective spatial images should play important roles in extending understanding of the fundamental mechanisms of laser damage. The staining procedures developed can be applied to study laser-damaged retina. Data were obtained demonstrating rapid mechanical motions in vertebrate photoreceptors. Such rapid mechanical motions which parallel electrophysiological responses in the cell may lie at the very basis of photoreceptor function. Laser-damage mechanisms should now be reevaluated in terms of this new data. The effect of laser light on these newly discovered mechanical motions will surely lead to new and improved understanding of low-level laser ocular hazards.

  5. A fundamental study on the [(μ-Cl)3 Mg2 (THF)6 ]+ dimer electrolytes for rechargeable Mg batteries

    DOE PAGES

    Liu, Tianbiao; Cox, Jonathan T.; Hu, Dehong; Deng, Xuchu; Hu, Jianzhi; Hu, Mary Y.; Xiao, Jie; Shao, Yuyan; Tang, Keqi; Liu, Jun

    2015-01-05

    We present a fundamental study on [(μ-Cl)3 Mg2 (THF)6 ]+ dimer electrolytes using various physical methods including Subambient Pressure Ionization with Nanoelectrospray Mass spectrometry (SPIN-MS), Raman spectroscopy, 25Mg{1H} NMR, 27Al{1H} NMR and electrochemical analysis. For the first time, long time sought THF solvated [MgCl]+ species was experimentally characterized by SPIN mass spectrometry in the solution of the Mgdimer containing electrolyte, confirming the mono-Cl- abstraction reaction between MgCl2 and an Al Lewis acid. Solvated MgCl2 in the electrolyte was confirmed by Raman spectroscopy. The experimental results establish the previously proposed dimerization equilibrium of solvated [MgCl]+ and MgCl2 with [(μ-Cl)3Mg2(THF)6]+.more » 25Mg{1H} NMR, 27Al{1H} NMR and electrochemical analysis on chloration reaction of [(μ-Cl)3Mg2(THF)6]AlPh3Cl with external Cl- led to further insights on the coordination chemistry of the dimer electrolyte. Finally, a comprehensive mechanism is proposed for the reversible electrochemical Mg deposition and stripping and Mg2+ and Cl- ion transports of the Mg dimer electrolytes in rechargeable Mg batteries.« less

  6. VLTI/AMBER Studies of the Atmospheric Structure and Fundamental Parameters of Red Giant and Supergiant Stars

    NASA Astrophysics Data System (ADS)

    Arroyo-Torres, B.; Wittkowski, M.; Marcaide, J. M.; Abellan, F. J.; Chiavassa, A.; Fabregat, J.; Freytag, B.; Guirado, J. C.; Hauschildt, P. H.; Marti-Vidal, I.; Quirrenbach, A.; Scholz, M.; Wood, P. R.

    2015-08-01

    We present recent near-IR interferometric studies of red giant and supergiant stars, which are aimed at obtaining information on the structure of the atmospheric layers and constraining the fundamental parameters of these objects. The observed visibilities of six red supergiants (RSGs), and also of one of the five red giants observed, indicate large extensions of the molecular layers, as previously observed for Mira stars. These extensions are not predicted by hydrostatic PHOENIX model atmospheres, hydrodynamical (RHD) simulations of stellar convection, or self-excited pulsation models. All these models based on parameters of RSGs lead to atmospheric structures that are too compact compared to our observations. We discuss how alternative processes might explain the atmospheric extensions for these objects. As the continuum appears to be largely free of contamination by molecular layers, we can estimate reliable Rosseland angular radii for our stars. Together with distances and bolometric fluxes, we estimate the effective temperatures and luminosities of our targets, locate them in the HR diagram, and compare their positions to recent evolutionary tracks.

  7. Fundamental studies of hydrogen attack in carbon-0.5molybdenum steel and weldments applied in petroelum and petrochemical industries

    NASA Astrophysics Data System (ADS)

    Liu, Peng

    High temperature hydrogen attack (HTHA) is a form of surface decarburization, internal decarburization, and/or intergranular cracking in steels exposed to high temperature (>400°F) and high hydrogen pressure. Hydrogen attack is an irreversible process which can cause permanent damage resulting in degradation of mechanical properties and failures such as leakage, bursting, fire, and/or explosion. The continuous progression of hydrogen attack in C-0.5Mo steel and weldments below the C-0.5Mo Nelson Curve has caused a significant concern for the integrity and serviceability of C-0.5Mo steel utilized for pressure vessels and piping in the petroleum refinery and petrochemical industries. A state-of-the-art literature review was implemented to provide a comprehensive overview of the published research efforts on hydrogen attack studies. The evolution of "Nelson Curves" for carbon steel, C-0.5Mo, and Cr-Mo steels was historically reviewed in regard to design applications and limitations. Testing techniques for hydrogen attack assessment were summarized under the categories of hydrogen exposure testing, mechanical evaluation, and dilatometric swelling testing. In accord with the demands of these industries, fundamental studies of hydrogen attack in C-0.5Mo steel and weldments were accomplished in terms of quantitative methodologies for hydrogen damage evaluation; hydrogen damage assessment of service exposed weldments and autoclave exposed materials; effects of carbon and alloying elements, heat treatments, hot and cold working, welding processes and postweld heat treatment (PWHT) on hydrogen attack susceptibility; development of continuous cooling transformation (CCT) diagrams for C-0.5Mo base metals and the coarse grained heat-affected zone (CGHAZ); carbide evaluation for the C-0.5Mo steel after service exposure and heat treatment; methane evolution by the reaction of hydrogen and carbides; hydrogen diffusion and methane pressure through the wall thickness of one

  8. Study of wood plastic composite in the presence of nitrogen containing additives

    NASA Astrophysics Data System (ADS)

    Ali, K. M. Idriss; Khan, Mubarak A.; Husain, M. M.

    1994-10-01

    Effect of nitrogen-containing additives in the study of wood plastic composites of MMA with simul and mango wood of Bangladesh has been investigated. Nine different additives were used and the additives containing carboamide group induce the highest tensile strength to the composite.

  9. Fundamentals of ionic conductivity relaxation gained from study of procaine hydrochloride and procainamide hydrochloride at ambient and elevated pressure.

    PubMed

    Wojnarowska, Z; Swiety-Pospiech, A; Grzybowska, K; Hawelek, L; Paluch, M; Ngai, K L

    2012-04-28

    The pharmaceuticals, procaine hydrochloride and procainamide hydrochloride, are glass-forming as well as ionically conducting materials. We have made dielectric measurements at ambient and elevated pressures to characterize the dynamics of the ion conductivity relaxation in these pharmaceuticals, and calorimetric measurements for the structural relaxation. Perhaps due to their special chemical and physical structures, novel features are found in the ionic conductivity relaxation of these pharmaceuticals. Data of conductivity relaxation in most ionic conductors when represented by the electric loss modulus usually show a single resolved peak in the electric modulus loss M(")(f) spectra. However, in procaine hydrochloride and procainamide hydrochloride we find in addition another resolved loss peak at higher frequencies over a temperature range spanning across T(g). The situation is analogous to many non-ionic glass-formers showing the presence of the structural α-relaxation together with the Johari-Goldstein (JG) β-relaxation. Naturally the analogy leads us to name the slower and faster processes resolved in procaine hydrochloride and procainamide hydrochloride as the primary α-conductivity relaxation and the secondary β-conductivity relaxation, respectively. The analogy of the β-conductivity relaxation in procaine HCl and procainamide HCl with JG β-relaxation in non-ionic glass-formers goes further by the finding that the β-conductivity is strongly related to the α-conductivity relaxation at temperatures above and below T(g). At elevated pressure but compensated by raising temperature to maintain α-conductivity relaxation time constant, the data show invariance of the ratio between the β- and the α-conductivity relaxation times to changes of thermodynamic condition. This property indicates that the β-conductivity relaxation has fundamental importance and is indispensable as the precursor of the α-conductivity relaxation, analogous to the relation found

  10. Fundamentals of ionic conductivity relaxation gained from study of procaine hydrochloride and procainamide hydrochloride at ambient and elevated pressure

    NASA Astrophysics Data System (ADS)

    Wojnarowska, Z.; Swiety-Pospiech, A.; Grzybowska, K.; Hawelek, L.; Paluch, M.; Ngai, K. L.

    2012-04-01

    The pharmaceuticals, procaine hydrochloride and procainamide hydrochloride, are glass-forming as well as ionically conducting materials. We have made dielectric measurements at ambient and elevated pressures to characterize the dynamics of the ion conductivity relaxation in these pharmaceuticals, and calorimetric measurements for the structural relaxation. Perhaps due to their special chemical and physical structures, novel features are found in the ionic conductivity relaxation of these pharmaceuticals. Data of conductivity relaxation in most ionic conductors when represented by the electric loss modulus usually show a single resolved peak in the electric modulus loss M″(f ) spectra. However, in procaine hydrochloride and procainamide hydrochloride we find in addition another resolved loss peak at higher frequencies over a temperature range spanning across Tg. The situation is analogous to many non-ionic glass-formers showing the presence of the structural α-relaxation together with the Johari-Goldstein (JG) β-relaxation. Naturally the analogy leads us to name the slower and faster processes resolved in procaine hydrochloride and procainamide hydrochloride as the primary α-conductivity relaxation and the secondary β-conductivity relaxation, respectively. The analogy of the β-conductivity relaxation in procaine HCl and procainamide HCl with JG β-relaxation in non-ionic glass-formers goes further by the finding that the β-conductivity is strongly related to the α-conductivity relaxation at temperatures above and below Tg. At elevated pressure but compensated by raising temperature to maintain α-conductivity relaxation time constant, the data show invariance of the ratio between the β- and the α-conductivity relaxation times to changes of thermodynamic condition. This property indicates that the β-conductivity relaxation has fundamental importance and is indispensable as the precursor of the α-conductivity relaxation, analogous to the relation found

  11. Final Report: DE- FC36-05GO15063, Fundamental Studies of Advanced High-Capacity, Reversible Metal Hydrides

    SciTech Connect

    Jensen, Craig; McGrady, Sean; Severa, Godwin; Eliseo, Jennifer; Chong, Marina

    2013-05-31

    The project was component of the US DOE, Metal Hydride Center of Excellence (MHCoE). The Sandia National Laboratory led center was established to conduct highly collaborative and multi-disciplinary applied R&D to develop new reversible hydrogen storage materials that meet or exceed DOE/FreedomCAR 2010 and 2015 system targets for hydrogen storage materials. Our approach entailed a wide variety of activities ranging from synthesis, characterization, and evaluation of new candidate hydrogen storage materials; screening of catalysts for high capacity materials requiring kinetics enhancement; development of low temperature methods for nano-confinement of hydrides and determining its effects on the kinetics and thermodynamics of hydrides; and development of novel processes for the direct re-hydrogenation of materials. These efforts have resulted in several advancements the development of hydrogen storage materials. We have greatly extended the fundamental knowledge about the highly promising hydrogen storage carrier, alane (AlH3), by carrying out the first crystal structure determinations and the first determination of the heats of dehydrogenation of β–AlH3 and γ-AlD3. A low-temperature homogenous organometallic approach to incorporation of Al and Mg based hydrides into carbon aerogels has been developed that that allows high loadings without degradation of the nano-porous scaffold. Nano-confinement was found to significantly improve the dehydrogenation kinetics but not effect the enthalpy of dehydrogenation. We conceived, characterized, and synthesized a novel class of potential hydrogen storage materials, bimetallic borohydrides. These novel compounds were found to have many favorable properties including release of significant amounts of hydrogen at moderate temperatures (75-190 º C). However, in situ IR studies in tandem with thermal gravimetric analysis have shown that about 0.5 equivalents of diborane are released during the

  12. Gas-Grain Simulation Facility: Fundamental studies of particle formation and interactions. Volume 2: Abstracts, candidate experiments and feasibility study

    NASA Technical Reports Server (NTRS)

    Fogleman, Guy (Editor); Huntington, Judith L. (Editor); Schwartz, Deborah E. (Editor); Fonda, Mark L. (Editor)

    1989-01-01

    An overview of the Gas-Grain Simulation Facility (GGSF) project and its current status is provided. The proceedings of the Gas-Grain Simulation Facility Experiments Workshop are recorded. The goal of the workshop was to define experiments for the GGSF--a small particle microgravity research facility. The workshop addressed the opportunity for performing, in Earth orbit, a wide variety of experiments that involve single small particles (grains) or clouds of particles. Twenty experiments from the fields of exobiology, planetary science, astrophysics, atmospheric science, biology, physics, and chemistry were described at the workshop and are outlined in Volume 2. Each experiment description included specific scientific objectives, an outline of the experimental procedure, and the anticipated GGSF performance requirements. Since these experiments represent the types of studies that will ultimately be proposed for the facility, they will be used to define the general science requirements of the GGSF. Also included in the second volume is a physics feasibility study and abstracts of example Gas-Grain Simulation Facility experiments and related experiments in progress.

  13. Fundamental studies in the molecular basis of laser-induced retinal damage. Annual report, September 1981-August 1982

    SciTech Connect

    Lewis

    1982-09-01

    This research led to new insights in the fundamental mechanisms involved in laser induced retinal damage and some of the fundamental work on these mechanisms lead to new and exciting avenues in the development of rapidly adjustable molecular light filters with important new possibilities for pulsed-laser eye protection. This report summarizes the significant progress of the past year: (1) Development and Fundamental Mechanism of a Rapidly Adjustable Molecular Filter for Pulsed Laser Eye Protection - this research direction resulted from our investigations on cones of the red-eared swamp turtle, Pseudemys scripta elegans. (2) The Optical Density of Turtle Oil Droplet Solutions - it is important both from a practical and fundamental point of view to determine the optical density of turtle oil-droplet suspensions. In view of the high optical densities in this system, tunable-laser resonance Raman spectroscopy, which is the only technique that has been able to provide high-resolution data, is the only technique that is potentially able to obtain the information. (3) Laser-Induced Molecular Alterations in Turtle Retina. (4) Light Driven Enzymatic Reactions in Photoreceptors. (5) Molecular Cytology of Rod Outer Segments.

  14. Effectiveness of a Fundamental Motor Skill Intervention for 4-Year-Old Children with Autism Spectrum Disorder: A Pilot Study

    ERIC Educational Resources Information Center

    Bremer, Emily; Balogh, Robert; Lloyd, Meghann

    2015-01-01

    A wait-list control experimental design was employed to investigate the effectiveness of a fundamental motor skill intervention at improving the motor skills, adaptive behavior, and social skills of 4-year-old children with autism spectrum disorder (experimental n?=?5, control n?=?4); the impact of intervention intensity was also explored. The…

  15. Load bearing and stiffness tailored NiTi implants produced by additive manufacturing: a simulation study

    NASA Astrophysics Data System (ADS)

    Rahmanian, Rasool; Shayesteh Moghaddam, Narges; Haberland, Christoph; Dean, David; Miller, Michael; Elahinia, Mohammad

    2014-03-01

    Common metals for stable long-term implants (e.g. stainless steel, Titanium and Titanium alloys) are much stiffer than spongy cancellous and even stiffer than cortical bone. When bone and implant are loaded this stiffness mismatch results in stress shielding and as a consequence, degradation of surrounding bony structure can lead to disassociation of the implant. Due to its lower stiffness and high reversible deformability, which is associated with the superelastic behavior, NiTi is an attractive biomaterial for load bearing implants. However, the stiffness of austenitic Nitinol is closer to that of bone but still too high. Additive manufacturing provides, in addition to the fabrication of patient specific implants, the ability to solve the stiffness mismatch by adding engineered porosity to the implant. This in turn allows for the design of different stiffness profiles in one implant tailored to the physiological load conditions. This work covers a fundamental approach to bring this vision to reality. At first modeling of the mechanical behavior of different scaffold designs are presented as a proof of concept of stiffness tailoring. Based on these results different Nitinol scaffolds can be produced by additive manufacturing.

  16. Lateralization of the frontal lobe functions elicited by a cognitive bias task is a fundamental process. Lesion study.

    PubMed

    Aoyagi, Kakurou; Aihara, Masao; Goldberg, Elkhonon; Nakazawa, Shinpei

    2005-09-01

    Cognitive neuroscience researchers have hypothesized that context-dependent and context-independent response selection is associated with the left and right frontal lobe, respectively, in right-handed adult males. Patients with left frontal lobe lesions show context-independent reasoning in a cognitive bias task (CBT), while those with right frontal lesions show context-dependent reasoning. Young children show more context-independent responses in a modified CBT (mCBT), while adolescents and adults show more context-dependent responses. We investigated the cognitive bias of right-handed children with unilateral frontal lobe lesions/epileptic foci to explore the plasticity of lateralization in the frontal lobes. The study included eight children with left frontal lobe lesions/epileptic foci (LLF) and four children with right frontal lobe lesions/epileptic foci (RLF). Twenty-three right-handed age-matched males served as controls. A computer presented version of the original card-choice task that was simplified and modified for children was used (mCBT). Simple visual stimuli differed dichotomously in shape, color, number, and shading. A target object presented alone was followed by two choices from which subjects made selection based on preference. Considering all four characteristics, the degree of similarity between the target and the subjects' choice was scored for 30 trials. A high score indicated a context-dependent response selection bias and a low score indicated a context-independent bias. The RLF subjects had a higher converted score (mean: 26.8+/-2.2), while LLF subjects showed a lower converted score (mean: 7.75+/-6.3). There were highly significant differences between LLF subjects and the other groups (P<0.001 vs. controls or RLF subjects). No significant correlations were observed between the converted scores and the age at onset, time since insult, or IQ in either LLF or RLF subjects. These findings suggest that the lateralization of frontal lobe

  17. Effectiveness of a fundamental motor skill intervention for 4-year-old children with autism spectrum disorder: A pilot study.

    PubMed

    Bremer, Emily; Balogh, Robert; Lloyd, Meghann

    2015-11-01

    A wait-list control experimental design was employed to investigate the effectiveness of a fundamental motor skill intervention at improving the motor skills, adaptive behavior, and social skills of 4-year-old children with autism spectrum disorder (experimental n = 5, control n = 4); the impact of intervention intensity was also explored. The experimental group significantly improved their object manipulation and overall motor scores from pre- to post-intervention. The wait-list control design revealed no group-by-time interactions; however, with the groups combined time was a significant factor for all motor variables. There were no significant changes in adaptive behavior and social skills. These preliminary findings suggest that a fundamental motor skill intervention may benefit young children with autism spectrum disorder. Future research with larger samples is warranted.

  18. A FUNDAMENTAL STUDY ON OBSERVATION DENSITY OF RAIN-GAUGE NETWORK OVER JAPAN USING MULTIPLE EVALUATION INDEX

    NASA Astrophysics Data System (ADS)

    Hayashi, Yoshiaki; Tebakari, Taichi; Yamasaki, Koreyoshi

    Rain-gauge stations have been operated by many agencies, thus temporal and spatial characteristics of rain-gauge network have not been studied. We studied the observation density of rain-gauge network over Japan using available data observed by Japan Meteorological Agency (JMA), the River Bureau under Ministry of Land, Infrastructure, Transport and Tourism (RB-MLIT) and local governments (L-Gov). As a result of analysis of elevation, rain-gauge stations have been installed at a constant rate by each elevation class of the topography, and Japan has no rain-gauge stations over altitude 2500m. As a result of observation density by mesh analysis, approximately 70% of rain-gauge stations could observe rainfall data. In addition, we analyzed between DID and flood/drought disaster in recent years and observation density over Japan.

  19. Exchange Rates and Fundamentals.

    ERIC Educational Resources Information Center

    Engel, Charles; West, Kenneth D.

    2005-01-01

    We show analytically that in a rational expectations present-value model, an asset price manifests near-random walk behavior if fundamentals are I (1) and the factor for discounting future fundamentals is near one. We argue that this result helps explain the well-known puzzle that fundamental variables such as relative money supplies, outputs,…

  20. Fundamentals of electrokinetics

    NASA Astrophysics Data System (ADS)

    Kozak, M. W.

    The study of electrokinetics is a very mature field. Experimental studies date from the early 1800s, and acceptable theoretical analyses have existed since the early 1900s. The use of electrokinetics in practical field problems is more recent, but it is still quite mature. Most developments in the fundamental understanding of electrokinetics are in the colloid science literature. A significant and increasing divergence between the theoretical understanding of electrokinetics found in the colloid science literature and the theoretical analyses used in interpreting applied experimental studies in soil science and waste remediation has developed. The soil science literature has to date restricted itself to the use of very early theories, with their associated limitations. The purpose of this contribution is to review fundamental aspects of electrokinetic phenomena from a colloid science viewpoint. It is hoped that a bridge can be built between the two branches of the literature, from which both will benefit. Attention is paid to special topics such as the effects of overlapping double layers, applications in unsaturated soils, the influence of dispersivity, and the differences between electrokinetic theory and conductivity theory.

  1. 7 CFR 1710.253 - Engineering and cost studies-addition of generation capacity.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 7 Agriculture 11 2010-01-01 2010-01-01 false Engineering and cost studies-addition of generation... TO ELECTRIC LOANS AND GUARANTEES Construction Work Plans and Related Studies § 1710.253 Engineering... engineering and cost studies as specified by RUS. The studies shall cover a period from the beginning of...

  2. 7 CFR 1710.253 - Engineering and cost studies-addition of generation capacity.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 7 Agriculture 11 2011-01-01 2011-01-01 false Engineering and cost studies-addition of generation... TO ELECTRIC LOANS AND GUARANTEES Construction Work Plans and Related Studies § 1710.253 Engineering... engineering and cost studies as specified by RUS. The studies shall cover a period from the beginning of...

  3. 7 CFR 1710.253 - Engineering and cost studies-addition of generation capacity.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 7 Agriculture 11 2013-01-01 2013-01-01 false Engineering and cost studies-addition of generation... TO ELECTRIC LOANS AND GUARANTEES Construction Work Plans and Related Studies § 1710.253 Engineering... engineering and cost studies as specified by RUS. The studies shall cover a period from the beginning of...

  4. 7 CFR 1710.253 - Engineering and cost studies-addition of generation capacity.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 7 Agriculture 11 2014-01-01 2014-01-01 false Engineering and cost studies-addition of generation... TO ELECTRIC LOANS AND GUARANTEES Construction Work Plans and Related Studies § 1710.253 Engineering... engineering and cost studies as specified by RUS. The studies shall cover a period from the beginning of...

  5. 7 CFR 1710.253 - Engineering and cost studies-addition of generation capacity.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 7 Agriculture 11 2012-01-01 2012-01-01 false Engineering and cost studies-addition of generation... TO ELECTRIC LOANS AND GUARANTEES Construction Work Plans and Related Studies § 1710.253 Engineering... engineering and cost studies as specified by RUS. The studies shall cover a period from the beginning of...

  6. Fundamental study of a refractory-based carbon fiber reinforced composite made by reactive melt infiltration for hypersonic applications

    NASA Astrophysics Data System (ADS)

    Wali, Natalie Alice

    Ceramic matrix composites are excellent candidates for ultrahigh temperature applications due their good physical properties, which are a combination of a chemically stable matrix and tough fiber reinforcement. This work is a fundamental study of a carbon fiber reinforced zirconium carbide composite (Cf/ZrC). The background chapter reviews reactive melt infiltration, which is the processing method used to make the Cf/ZrC composite. The first chapter discusses the microstructural characterization and development of Cf/ZrC. A formation mechanism of the unique matrix microstructure is proposed based on the characterization results. In the second chapter the mechanical properties of Cf/ZrC were determined. The fracture toughness at room temperature is obtained with a standard four point bend test, while flexural strength of Cf/ZrC is obtained to the ultra high temperature regime. For high temperatures a testing rig was modified to operate in inert atmosphere and tests were conducted at 1100 °C, 1350 °C and 1650 °C. Correlation is made between the flexural strength and fiber coatings of two different composite types. In situ compression tests were performed a modified SEM. Digital image correlation was used to monitor strains during compression. The stress-strain information is correlated to surface deformation. The environmental durability and oxidation behavior of Cf/ZrC and ZrC is detailed in the third and fourth chapters. The oxidation and shock behavior of Cf/ZrC were observed under both slow and rapid heating rates to ultra high temperatures. For rapid heating rates a panel was subjected to heating at steady-state and non-steady state heat flux. For slow heating rates specimen coupons were heated at 2000 °C in a bottom-loading furnace. Specimens were characterized post-test by x-ray diffraction, electron microscopy, electron probe microanalysis, and optical microscopy. The oxidation kinetics of Cf/ZrC composites and ZrC powders (45 micron and 60 nanometer

  7. Fundamental studies of the removal of contaminants from ground and waste waters via reduction by zero-valent metals. 1998 annual progress report

    SciTech Connect

    Yarmoff, J.A.; Amrhein, C.

    1998-06-01

    'Contaminated groundwater and surface waters are a problem throughout the US and the world. In many instances, the types of contamination can be directly attributed to man''s actions. For instance, the burial of wastes, casual disposal of solvents in unlined pits, and the development of irrigated agriculture have all contributed to groundwater and surface water contamination. The kinds of contaminants include chlorinated solvents and toxic trace elements that are soluble and mobile in soils and aquifers. Oxyanions of selenium, chromium, uranium, arsenic, and chlorine (as perchlorate) are frequently found as contaminants on many DOE sites. In addition, the careless disposal of cleaning solvents, such as carbon tetrachloride and trichloroethylene, has further contaminated many groundwaters at these sites. Oxyanions of selenium, nitrogen, arsenic, vanadium, uranium, chromium, and molybdenum are contaminants in agricultural areas of the Western US. The management of these waters requires treatment to remove the contaminants before reuse or surface water disposal. In one instance in the Central Valley of California, the discharge of selenate-contaminated shallow groundwater to a wildlife refuge caused catastrophic bird deaths and deformities of embryos. A potential remediation method for many of these oxyanions and chlorinated-solvents is to react the contaminated water with zero-valent iron. In this reaction, the iron serves as both an electron source and as a catalyst. Elemental iron is already being used on an experimental basis. Both in-situ reactive barriers and above-ground reactors are being developed for this purpose. However, the design and operation of these treatment systems requires a detailed process-level understanding of the interactions between the contaminants and the iron surfaces. Only limited success has been achieved in the field, partly because the basic surface chemical reactions are not well understood. The authors are performing fundamental

  8. Fundamental Study on Applicability of Powder-Based 3D Printer for Physical Modeling in Rock Mechanics

    NASA Astrophysics Data System (ADS)

    Fereshtenejad, Sayedalireza; Song, Jae-Joon

    2016-06-01

    Applications of 3D printing technology become more widespread in many research fields because of its rapid development and valuable capabilities. In rock mechanics and mining engineering, this technology has the potential to become a useful tool that might help implement a number of research studies previously considered impractical. Most commercial 3D printers cannot print prototypes with mechanical properties that match precisely those of natural rock samples. Therefore, some additional enhancements are required for 3D printers to be effectively utilized for rock mechanics applications. In this study, we printed and studied specimens using a powder-based commercial ZPrinter® 450 with ZP® 150 powder and Zb® 63 binder used as raw materials. The specimens printed by this 3D printer exhibited relatively low strength and ductile behavior, implying that it needs further improvements. Hence, we focused on several ways to determine the best combination of printing options and post-processing including the effects of the printing direction, printing layer thickness, binder saturation level, and heating process on the uniaxial compressive strength (UCS) and stress-strain behavior of the printed samples. The suggested procedures have demonstrated their effectiveness by obtaining the printed samples that behave similarly to the natural rocks with low UCS. Although our optimization methods were particularly successful, further improvements are required to expand 3D printer application in the area of rock mechanics.

  9. Fundamental study of ash formation and deposition: Effect of reducing stoichiometry. Final report, April 1, 1993--June 30, 1995

    SciTech Connect

    Bool, L.E. III; Helble, J.J.; Shah, N.

    1995-09-01

    The technical objectives of this project are: (1) To identify the partitioning of inorganic coal constituents among vapor, submicron fume, and fly ash products generated during the combustion of pulverized coal under a variety of combustion conditions. Fuel lean and fuel rich combustion conditions are considered. (2) To identify and quantify the fundamental processes by which the transformations of minerals and organically-associated inorganic species occur. Emphasis is placed on identifying any changes that occur as a result of combustion under sub-stoichiometric combustion conditions. (3) To incorporate the effects of combustion stoichiometry into an Engineering Model for Ash Formation.

  10. Fundamental Studies of The Removal of Contaminants from Ground and Waste Waters Via Reduction By Zero-Valent metals

    SciTech Connect

    Jory A. Yarmoff; Christopher Amrhein

    2002-04-23

    Oxyanions of uranium, selenium, chromium, arsenic, technetium, and chlorine (as perchlorate) are frequently found as contaminants on many DOE sites, and in other areas of the U.S.. A potential remediation method is to react the contaminated water with zero-valent iron (ZVI). We are performing fundamental investigations of the interactions of the relevant compounds with Fe filings and single- and poly-crystalline surfaces. The aim of this work is to develop the physical and chemical understanding that is necessary for the development of cleanup techniques and procedures.

  11. Centaur feedline dynamics study using power spectral methods. [fundamental mode resonant frequencies of RL-10 oxygen and hydrogen feed lines

    NASA Technical Reports Server (NTRS)

    Lorenzo, C. F.

    1974-01-01

    Tests were conducted to determine the dynamic characteristics of the Centaur/RL-10 oxygen and hydrogen feedlines. The fundamental-mode resonant frequencies were determined by applying power spectral methods to noise-generated data from hot firings of the RL-10 engine. The effect of net positive suction pressure of the main feed pumps on resonant frequency characteristics was determined to be a straight-line relation. Power spectral methods were also used to determine the dynamic characteristics of the boost pumps.

  12. A Fundamental Study of Vapor Generation from Nonaqeuous Phase Liquid Sources as a Function of Soil Moisture

    NASA Astrophysics Data System (ADS)

    Petri, B. G.; Illangasekare, T. H.; Sauck, C.; Sakaki, T.; Christ, J.

    2011-12-01

    The intrusion of vapor phase contaminants from subsurface sources into occupied buildings represents a possible exposure pathway and threat to human health. To make informed risk-management decisions regarding this pathway, it is important to build a conceptual model of the physical and chemical processes that govern vapor intrusion, and specifically to understand the source of the contaminant vapors. One vapor source includes nonaqueous phase liquids (NAPLs) entrapped within the vadose zone. The generation of vapors in the vadose zone from these sources under transient conditions imparted by the heat and water flux boundary conditions at the land surface involves complex mass-transfer processes; partitioning occurs simultaneously between NAPL, air, water and soil phases. Advection and diffusion within the air and water phases also play a critical role. It is our contention that the mass transfer to the air phase is a strong function of the soil moisture conditions in the direct vicinity of the NAPL source. We hypothesize that NAPL sources located in zones of high water saturation will have lower effective mass transfer rates than NAPLs located in low saturation regions, due to the higher diffusion resistance in the aqueous phase. Several studies have investigated NAPL mass transfer under unsaturated conditions and variable soil moisture (Ho and Udell 1992; Wilkins et al. 1995; Yoon et al. 2002); however, to build on this knowledge base, laboratory experimentation is needed under controlled conditions that considers spatially and temporally variable airflow fields and soil moisture saturations that occur in source zones in response to rain events and other climatic phenomena. The fundamental knowledge needed to address field problems cannot be generated in field systems due to lack of control and geologic complexities that are hard to characterize, leading to the need to use intermediate scale test systems. To investigate this problem, experiments were first

  13. Fundamental Studies on the Enzymatic Liquefaction and Rheology of Cellulosic Biomass viaMagnetic Resonance Imaging Velocimetry

    NASA Astrophysics Data System (ADS)

    Cardona, Maria Jose

    Worldwide need for alternatives to fossil fuels has driven significant research effort toward the development and scale-up of sustainable forms of energy. Second-generation biofuels, obtained from the breakdown of lignocellulosic biomass (e.g., agricultural residues), present a promising alternative. In biofuel production, the enzymatic hydrolysis of cellulose to glucose is currently one of the most expensive steps in the biochemical breakdown of lignocellulosic biomass. Economic considerations for large-scale implementation of this process demand operation at high solids loadings of biomass (>15% (w/w)) due to potential for higher product concentrations and reduction of water usage throughout the biorefining process. In the high-solids regime, however, biomass slurries form a high viscosity, non-Newtonian slurry that introduces processing challenges, especially during the initial stages of hydrolysis (liquefaction), due to the low availability of water in the bulk phase. Furthermore, a concomitant reduction in glucose yields with increase in solids loadings has been observed, a phenomenon that is not well understood, but if overcome could hold the key to achieving desirable yields during hydrolysis. In order to better understand liquefaction, a magnetic resonance imaging (MRI) rheometer was used to perform in-line, in situ, real-time, and noninvasive studies on biomass slurries undergoing enzymatic hydrolysis. Batch and fed-batch experiments were done on lignocellulosic and cellulosic substrates with both purified and mixtures of enzymes, under various reaction conditions. The mechanism of liquefaction was found to be decoupled from the mechanism of saccharification. In addition, end product inhibition was found to have an impact on both saccharification and liquefaction during the initial stage of hydrolysis, which has an impact on scale-up of hydrolysis processes. Lastly, to address and overcome high-solids limitations, a fed-batch liquefaction process based on

  14. Studies of jet fuel additives using the quartz crystal microbalance and pressure monitoring at 140 C

    SciTech Connect

    Zabarnick, S.; Grinstead, R.R. . Aerospace Mechanics Div./KL-463)

    1994-11-01

    Recent advances in jet aircraft and engine technology have placed an ever increasing heat load on the aircraft. The bulk of this excess heat is absorbed by the aircraft fuel, as jet fuel is used as the primary coolant for the numerous heat sources. The quartz crystal microbalance (QCM) and pressure monitoring are used for the evaluation of jet fuel additives for the improvement of jet fuel thermal stability. The mechanisms of additive behavior are determined by measuring the time-dependent deposition with the QCM and oxidation by pressure measurements. Studies at various additive concentrations permits the determination of optimum additive concentrations. Additive packages made of mixtures of antioxidants, detergent/dispersants, and metal deactivators are shown to yield good improvements in thermal stability over a wide range of jet fuel types.

  15. Fundamental study of ash formation and deposition: Effect of reducing stoichiometry. Quarterly report No. 4, 1 January--31 March 1994

    SciTech Connect

    Helble, J.J.; Bool, L.E.; Senior, C.L.; Sarofim, A.F.; Zeng, Taofang; Huffman, G.P.; Huggins, F.E.; Shah, N.

    1994-05-01

    The technical objectives of this project are: (a) To identify the partitioning of inorganic coal constituents among vapor, submicron fume, and fly ash products generated during the combustion of pulverized coal under a variety of combustion conditions. Fuel lean and fuel rich combustion conditions will be considered. (b) To identify and quantify the fundamental processes by which the transformations of minerals and organically associated inorganic species occurs. Emphasis will be placed on identifying any changes that occur as a result of combustion under sub-stoichiometric combustion conditions. (c) To incorporate the effects of combustion stoichiometry into an engineering model for ash formation based upon the understanding developed in (a) and (b). When completed, this model will predict the particle size and chemical composition distributions of ash formed during the combustion of pulverized coal under a broad range of conditions.

  16. Final Technical Report, Grant DE-FG02-87ER13714, "Fundamental Studies of Metastable Liquids"

    SciTech Connect

    Pablo G. Debenedetti

    2009-03-09

    Grant DE-FG02-87ER13714 supported fundamental work on the physical properties of metastable liquids from 6/1/87 to 4/30/08. Renewal proposals were submitted every three years (1990, 1993, 1996, 1999, 2002, 2005), and included, in every case, a detailed Final Technical Report on the previous three years. Accordingly, the bulk of this report covers the final 2-year period 5/1/06 to 4/30/08 of this grant, which is not covered in any of the previous Final Technical Reports. This is preceded by a brief overview of the main research objectives and principal accomplishments during these very fruitful and productive 21 years of DOE-funded research.

  17. Analytical study of seismic effects of a solar receiver mounted on concrete towers with different fundamental periods

    NASA Astrophysics Data System (ADS)

    Deng, Lin

    2016-05-01

    This paper examines the seismic effects experienced by a solar receiver mounted on concrete towers with different fundamental periods. Ten concrete towers are modeled with the empty solar receiver structure and loaded solar receiver structure to examine the tower seismic effects on the solar receiver. The fundamental periods of the towers range from 0.22 seconds to 4.58 seconds, with heights ranging from 40.5 meters to 200 meters. Thirty earthquake ground motion records are used to investigate the responses of each of the combined receiver-on-tower models as well as the receiver-on-ground models by the STAAD Pro software using time history analyses. The earthquake ground motion records are chosen based on the ratio of the peak ground acceleration to the peak ground velocity, ranging from 0.29 g/m/s to 4.88 g/m/s. For each of the combined models, the base shear at the interface between the receiver and the concrete tower is compared with the base shear of the receiver-on-ground model, and the ratio of the two base shears represents the structure amplification factor. It is found that the peak mean plus one standard deviation value of the structure amplification factor matches well with equation 13.3-1 in ASCE 7-10 for the empty solar receiver structure. However, when the solar receiver structure is loaded with dead loads, the peak value is greatly suppressed, and using equation 13.3-1 in ASCE 7-10 will be overly conservative.

  18. Coprocessing through fundamental and mechanistic studies in hydrogen transfer and catalysis. Quarterly report, September 26, 1991--December 26, 1991

    SciTech Connect

    Curtis, C.W.

    1991-12-31

    The research conducted during this quarter evaluated hydrogen transfer from hydroaromatics and cyclic olefins to aromatics under thermal and catalytic conditions. The reactions under study involved thermal reactions of a cyclic olefin, isotetralin (ISO), with aromatics, anthracene (ANT) and pyrene (PYR). These reactions completed a set of experiments with hydrogen-rich species and aromatics previously reported that included cycloalkanes of perhydropyrene (PHP) and perhydroanthracene (PHA), hydroaromatic donors, tetralin (TET) and dihydroanthracene (DHA), cyclic olefins, hexahydroanthracene (HHA) and ISO, and aromatics, PYR and ANT. Catalytic reactions performed this quarter used a sulfur catalyst that had been shown by Rudnick to affect the hydrogen transfer from cycloalkanes to aromatics and/or coal. Rudnick investigated the dehydrogenation of alicyclic compounds converting them to the corresponding aromatic compounds in a process in which the alicyclic compounds served as hydrogen donors. Thiophenol and thiol were effective catalysts and helped promote the conversion of alicyclic compounds to aromatic compounds. The research performed in our laboratory focused on evaluating the effect of a sulfur catalyst on the transfer of hydrogen from cycloalkanes like perhydropyrene (PHP) to aromatics like anthracene under catalytic conditions. The catalyst used in this study was sulfur generated from thiophenol present at a concentration level of 2000 ppm of sulfur. The reactions were performed under two temperature conditions, 380 and 440{degrees}C; both thermal and catalytic reactions were performed for comparison. In addition, the individual cycloalkane and aromatic compounds were reacted under these conditions so that a direct comparison of the effect of temperature and of catalyst on the reaction products formed could be made.

  19. Evaluating Drugs and Food Additives for Public Use: A Case Studies Approach.

    ERIC Educational Resources Information Center

    Merritt, Sheridan V.

    1980-01-01

    Described is a case study used in an introductory college biology course that provides a basis for generating debate on an issue concerning the regulation of controversial food additives and prescription drugs. The case study contained within this article deals with drug screening, specifically with information related to thalidomide. (CS)

  20. Fundamentals of Geophysics

    NASA Astrophysics Data System (ADS)

    Lowrie, William

    1997-10-01

    This unique textbook presents a comprehensive overview of the fundamental principles of geophysics. Unlike most geophysics textbooks, it combines both the applied and theoretical aspects to the subject. The author explains complex geophysical concepts using abundant diagrams, a simplified mathematical treatment, and easy-to-follow equations. After placing the Earth in the context of the solar system, he describes each major branch of geophysics: gravitation, seismology, dating, thermal and electrical properties, geomagnetism, paleomagnetism and geodynamics. Each chapter begins with a summary of the basic physical principles, and a brief account of each topic's historical evolution. The book will satisfy the needs of intermediate-level earth science students from a variety of backgrounds, while at the same time preparing geophysics majors for continued study at a higher level.

  1. Molecular modeling of directed self-assembly of block copolymers: Fundamental studies of processing conditions and evolutionary pattern design

    NASA Astrophysics Data System (ADS)

    Khaira, Gurdaman Singh

    Rapid progress in the semi-conductor industry has pushed for smaller feature sizes on integrated electronic circuits. Current photo-lithographic techniques for nanofabrication have reached their technical limit and are problematic when printing features small enough to meet future industrial requirements. "Bottom-up'' techniques, such as the directed self-assembly (DSA) of block copolymers (BCP), are the primary contenders to compliment current "top-down'' photo-lithography ones. For industrial requirements, the defect density from DSA needs to be less than 1 defect per 10 cm by 10 cm. Knowledge of both material synthesis and the thermodynamics of the self-assembly process are required before optimal operating conditions can be found to produce results adequate for industry. The work present in this thesis is divided into three chapters, each discussing various aspects of DSA as studied via a molecular model that contains the essential physics of BCP self-assembly. Though there are various types of guiding fields that can be used to direct BCPs over large wafer areas with minimum defects, this study focuses only on chemically patterned substrates. The first chapter addresses optimal pattern design by describing a framework where molecular simulations of various complexities are coupled with an advanced optimization technique to find a pattern that directs a target morphology. It demonstrates the first ever study where BCP self-assembly on a patterned substrate is optimized using a three-dimensional description of the block-copolymers. For problems pertaining to DSA, the methodology is shown to converge much faster than the traditional random search approach. The second chapter discusses the metrology of BCP thin films using TEM tomography and X-ray scattering techniques, such as CDSAXS and GISAXS. X-ray scattering has the advantage of being able to quickly probe the average structure of BCP morphologies over large wafer areas; however, deducing the BCP morphology

  2. Study raises questions about measurement of 'additionality,'or maintaining domestic health spending amid foreign donations.

    PubMed

    Garg, Charu C; Evans, David B; Dmytraczenko, Tania; Izazola-Licea, José-Antonio; Tangcharoensathien, Viroj; Ejeder, Tessa Tan-Torres

    2012-02-01

    Donor nations and philanthropic organizations increasingly require that funds provided for a specific health priority such as HIV should supplement domestic spending on that priority-a concept known as "additionality." We investigated the "additionality" concept using data from Honduras, Rwanda, and Thailand, and we found that the three countries increased funding for HIV in response to increased donor funding. In contrast, the study revealed that donors, faced with increased Global Fund resources for HIV in certain countries, tended to decrease their funding for HIV or shift funds for use in non-HIV health areas. More broadly, we found many problems in the measurement and interpretation of additionality. These findings suggest that it would be preferable for donors and countries to agree on how best to use available domestic and external funds to improve population health, and to develop better means of tracking outcomes, than to try to develop more sophisticated methods to track additionality.

  3. SHEEP MOUNTAIN WILDERNESS STUDY AREA AND CUCAMONGA WILDERNESS AND ADDITIONS, CALIFORNIA.

    USGS Publications Warehouse

    Evans, James G.; Ridenour, James

    1984-01-01

    The Sheep Mountain Wilderness Study Area and Cucamonga Wilderness and additions encompass approximately 104 sq mi of the eastern San Gabriel Mountains, Los Angeles and San Bernardino Counties, California. A mineral survey indicates areas of probable and substantiated tungsten and gold resource potential for parts of the Sheep Mountain Wilderness Study Area and an area of probable tungsten and gold resource potential in the Cucamonga Wilderness and additions. The rugged topography, withdrawal of lands from mineral entry to protect watershed, and restricted entry of lands during periods of high fire danger have contributed to the continuing decline in mineral exploration. The geologic setting precludes the presence of energy resources.

  4. Influence of Polarization on Carbohydrate Hydration: A Comparative Study Using Additive and Polarizable Force Fields.

    PubMed

    Pandey, Poonam; Mallajosyula, Sairam S

    2016-07-14

    Carbohydrates are known to closely modulate their surrounding solvent structures and influence solvation dynamics. Spectroscopic investigations studying far-IR regions (below 1000 cm(-1)) have observed spectral shifts in the libration band (around 600 cm(-1)) of water in the presence of monosaccharides and polysaccharides. In this paper, we use molecular dynamics simulations to gain atomistic insight into carbohydrate-water interactions and to specifically highlight the differences between additive (nonpolarizable) and polarizable simulations. A total of six monosaccharide systems, α and β anomers of glucose, galactose, and mannose, were studied using additive and polarizable Chemistry at HARvard Macromolecular Mechanics (CHARMM) carbohydrate force fields. Solvents were modeled using three additive water models TIP3P, TIP4P, and TIP5P in additive simulations and polarizable water model SWM4 in polarizable simulations. The presence of carbohydrate has a significant effect on the microscopic water structure, with the effects being pronounced for proximal water molecules. Notably, disruption of the tetrahedral arrangement of proximal water molecules was observed due to the formation of strong carbohydrate-water hydrogen bonds in both additive and polarizable simulations. However, the inclusion of polarization resulted in significant water-bridge occupancies, improved ordered water structures (tetrahedral order parameter), and longer carbohydrate-water H-bond correlations as compared to those for additive simulations. Additionally, polarizable simulations also allowed the calculation of power spectra from the dipole-dipole autocorrelation function, which corresponds to the IR spectra. From the power spectra, we could identify spectral signatures differentiating the proximal and bulk water structures, which could not be captured from additive simulations. PMID:27266974

  5. Fundamental Physical Constants

    National Institute of Standards and Technology Data Gateway

    SRD 121 CODATA Fundamental Physical Constants (Web, free access)   This site, developed in the Physics Laboratory at NIST, addresses three topics: fundamental physical constants, the International System of Units (SI), which is the modern metric system, and expressing the uncertainty of measurement results.

  6. Fundamentals of Physics

    NASA Astrophysics Data System (ADS)

    Halliday, David; Resnick, Robert; Walker, Jearl

    2003-01-01

    No other book on the market today can match the success of Halliday, Resnick and Walker's Fundamentals of Physics! In a breezy, easy-to-understand style the book offers a solid understanding of fundamental physics concepts, and helps readers apply this conceptual understanding to quantitative problem solving.

  7. Experimental study of impact-cratering damage on brittle cylindrical column model as a fundamental component of space architecture

    NASA Astrophysics Data System (ADS)

    Fujiwara, Akira; Onose, Naomi; Setoh, Masato; Nakamura, Akiko M.; Hiraoka, Kensuke; Hasegawa, Sunao; Okudaira, Kyoko

    2014-10-01

    The cylindrical column of brittle material processed from soil and rock is a fundamental component of architectures on the surface of solid bodies in the solar system. One of the most hazardous events for the structure is damaging by hypervelocity impacts by meteoroids and debris. In such a background, cylindrical columns made of plaster of Paris and glass-bead-sintered ceramic were impacted by spherical projectiles of nylon, glass, and steel at velocity of about 1-4.5 km/s. Measured crater radii, depth, and excavated mass expressed by a function of the cylinder radius are similar irrespective of the target material, if those parameters are normalized by appropriate parameters of the crater produced on the flat-surface target. The empirical scaling relations of the normalized crater radii and depth are provided. Using them, crater dimensions and excavated mass of crater on cylindrical surface of any radius can be predicted from the existing knowledge of those for flat surface. Recommendation for the minimum diameter of a cylinder so as to resist against a given impact is provided.

  8. Comparative study of electrolyte additives using electrochemical impedance spectroscopy on symmetric cells

    NASA Astrophysics Data System (ADS)

    Petibon, R.; Sinha, N. N.; Burns, J. C.; Aiken, C. P.; Ye, Hui; VanElzen, Collette M.; Jain, Gaurav; Trussler, S.; Dahn, J. R.

    2014-04-01

    The effect of various electrolyte additives and additive combinations added to a 1 M LiPF6 EC:EMC electrolyte on the positive and negative electrodes surface of 1 year old wound LiCoO2/graphite cells and Li[Ni0.4Mn0.4Co0.2])O2/graphite cells was studied using electrochemical impedance spectroscopy (EIS) on symmetric cells. The additives tested were: vinylene carbonate (VC), trimethoxyboroxine (TMOBX), fluoroethylene carbonate (FEC), lithium bis(trifluoromethanesulfonyl)imide (LiTFSI), and H2O alone or in combination. In general, compared to control electrolyte, the additives tested reduced the impedance of the positive electrode and increased the impedance of the negative electrode with the exception of LiTFSI in Li[Ni0.4Mn0.4Co0.2]O2/graphite wound cells. Higher charge voltage led to higher positive electrode impedance, with the exception of 2%VC + 2% FEC, and 2% LiTFSI. In some cases, some additives when mixed with another controlled the formation of the SEI at one electrode, and shared the formation of the SEI at one electrode when mixed with a different additive.

  9. Generating Scenarios of Addition and Subtraction: A Study of Japanese University Students

    ERIC Educational Resources Information Center

    Kinda, Shigehiro

    2013-01-01

    Students are presented with problems involving three scenario types of addition and subtraction in elementary mathematics: one dynamic ("Change") and two static ("Combine, Compare"). Previous studies have indicated that the dynamic type is easier for school children, whereas the static types are more difficult and comprehended only gradually…

  10. A fundamental study of the impact of pressure on the adsorption mechanism in reversed-phase liquid chromatography.

    PubMed

    Åsberg, Dennis; Samuelsson, Jörgen; Fornstedt, Torgny

    2016-07-29

    A fundamental investigation of the pressure effect on individual adsorption sites was undertaken based on adsorption energy distribution and adsorption isotherm measurements. For this purpose, we measured adsorption equilibrium data at pressures ranging from 100 to 1000bar at constant flow and over a wide concentration range for three low-molecular-weight solutes, antipyrine, sodium 2-naphthalenesulfonate, and benzyltriethylammonium chloride, on an Eternity C18 stationary phase. The adsorption energy distribution was bimodal for all solutes, remaining clearly so at all pressures. The bi-Langmuir model best described the adsorption in these systems and two types of adsorption sites were identified, one with a low and another with a high energy of interaction. Evidence exists that the low-energy interactions occur at the interface between the mobile and stationary phases and that the high-energy interactions occur nearer the silica surface, deeper in the C18 layer. The contribution of each type of adsorption site to the retention factor was calculated and the change in solute molar volume from the mobile to stationary phase during the adsorption process was estimated for each type of site. The change in solute molar volume was 2-4 times larger at the high-energy site, likely because of the greater loss of solute solvation layer when penetrating deeper into the C18 layer. The association equilibrium constant increased with increasing pressure while the saturation capacity of the low-energy site remained almost unchanged. The observed increase in saturation capacity for the high-energy site did not affect the column loading capacity, which was almost identical at 50- and 950-bar pressure drops over the column.

  11. Experimental study of combustion of decane, dodecane and hexadecane with polymeric and nano-particle additives

    NASA Astrophysics Data System (ADS)

    Ghamari, Mohsen; Ratner, Albert

    2015-11-01

    Recent studies have shown that adding combustible nano-particles could have promising effects on increasing burning rate of liquid fuels. Combustible nano-particles could enhance the heat conduction and mixing within the droplet. Polymers have also higher burning rate than regular hydrocarbon fuels because of having the flame closer to the droplet surface. Therefore adding polymeric additive could have the potential to increase the burning rate. In this study, combustion of stationary fuel droplets of n-Decane, n-Dodecane and n-Hexadecane doped with different percentages of a long chain polymer and also a very fine nano carbon was examined and compared with the pure hydrocarbon behavior. In contrast with hydrocarbon droplets with no polymer addition, several zones of combustion including a slow and steady burning zone, a strong swelling zone and a final fast and fairly steady combustion zone were also detected. In addition, increasing polymer percentage resulted in a more extended swelling zone and shorter slow burning zone in addition to a shorter total burning time. Addition of nano-particles also resulted in an overall increased burning rate and shortened burning time which is due to enhanced heat conduction within the droplet.

  12. Mental addition in bilinguals: an FMRI study of task-related and performance-related activation.

    PubMed

    Lin, Jo-Fu Lotus; Imada, Toshiaki; Kuhl, Patricia K

    2012-08-01

    Behavioral studies show that bilinguals are slower and less accurate when performing mental calculation in their nondominant (second; L2) language than in their dominant (first; L1) language. However, little is known about the neural correlates associated with the performance differences observed between bilinguals' 2 languages during arithmetic processing. To address the cortical activation differences between languages, the current study examined task-related and performance-related brain activation during mental addition when problems were presented auditorily in participants' L1 and L2. Eleven Chinese-English bilinguals heard 2-digit addition problems that required exact or approximate calculations. Functional magnetic resonance imaging results showed that auditorily presented multidigit addition in bilinguals activates bilateral inferior parietal and inferior frontal regions in both L1 and L2. Language differences were observed in the form of greater activation for L2 exact addition in the left inferior frontal area. A negative correlation between brain activation and behavioral performance during mental addition in L2 was observed in the left inferior parietal area. Current results provide further evidence for the effects of language-specific experience on arithmetic processing in bilinguals at the cortical level.

  13. Sequential neural processes in abacus mental addition: an EEG and FMRI case study.

    PubMed

    Ku, Yixuan; Hong, Bo; Zhou, Wenjing; Bodner, Mark; Zhou, Yong-Di

    2012-01-01

    Abacus experts are able to mentally calculate multi-digit numbers rapidly. Some behavioral and neuroimaging studies have suggested a visuospatial and visuomotor strategy during abacus mental calculation. However, no study up to now has attempted to dissociate temporally the visuospatial neural process from the visuomotor neural process during abacus mental calculation. In the present study, an abacus expert performed the mental addition tasks (8-digit and 4-digit addends presented in visual or auditory modes) swiftly and accurately. The 100% correct rates in this expert's task performance were significantly higher than those of ordinary subjects performing 1-digit and 2-digit addition tasks. ERPs, EEG source localizations, and fMRI results taken together suggested visuospatial and visuomotor processes were sequentially arranged during the abacus mental addition with visual addends and could be dissociated from each other temporally. The visuospatial transformation of the numbers, in which the superior parietal lobule was most likely involved, might occur first (around 380 ms) after the onset of the stimuli. The visuomotor processing, in which the superior/middle frontal gyri were most likely involved, might occur later (around 440 ms). Meanwhile, fMRI results suggested that neural networks involved in the abacus mental addition with auditory stimuli were similar to those in the visual abacus mental addition. The most prominently activated brain areas in both conditions included the bilateral superior parietal lobules (BA 7) and bilateral middle frontal gyri (BA 6). These results suggest a supra-modal brain network in abacus mental addition, which may develop from normal mental calculation networks.

  14. Characterization of fundamental catalytic properties of MoS2/WS2 nanotubes and nanoclusters for desulfurization catalysis - a surface temperature study

    SciTech Connect

    U. Burghaus

    2012-07-05

    The prior project consisted of two main project lines. First, characterization of novel nanomaterials for hydrodesulfurization (HDS) applications. Second, studying more traditional model systems for HDS such as vapor-deposited silica-supported Mo and MoSx clusters. In the first subproject, we studied WS2 and MoS2 fullerene-like nanoparticles as well as WS2 nanotubes. Thiophene (C4H4S) was used as the probe molecule. Interestingly, metallic and sulfur-like adsorption sites could be identified on the silica-supported fullerene-particles system. Similar structures are seen for the traditional system (vapor-deposited clusters). Thus, this may be a kinetics fingerprint feature of modern HDS model systems. In addition, kinetics data allowed characterization of the different adsorption sites for thiophene on and inside WS2 nanotube bundles. The latter is a unique feature of nanotubes that has not been reported before for any inorganic nanotube system; however, examples are known for carbon nanotubes, including prior work of the PI. Although HDS has been studied for decades, utilizing nanotubes as nanosized HDS reactors has never been tried before, as far as we know. This is of interest from a fundamental perspective. Unfortunately, the HDS activity of the nanocatalysts at ultra-high vacuum (UHV) conditions was close to the detection limit of our techniques. Therefore, we propose to run experiments at ambient pressure on related nanopowder samples as part of the renewal application utilizing a now-available GC (gas chromatograph) setup. In addition, Ni and Co doped nanocatalyts are proposed for study. These dopants will boost the catalytic activity. In the second subproject of the prior grant, we studied HDS-related chemistry on more traditional supported cluster catalysts. Mo clusters supported by physical vapor deposition (PVD) on silica have been characterized. Two reaction pathways are evident when adsorbing thiophene on Mo and MoSx clusters: molecular adsorption and

  15. Fundamental studies of the removal of contaminants from ground and waste waters via reduction by zero-valent metals. Annual progress report, September 1, 1996--August 31, 1997

    SciTech Connect

    Yarmoff, J.A.; Amrhein, C.

    1997-01-01

    contaminants and the iron surfaces. Only limited success has been achieved in the field, partly because the basic surface chemical reactions are not well understood. The authors are performing fundamental investigations of the interactions of the relevant chlorinated solvents, trace elements, and trace element-containing compounds with single- and poly-crystalline Fe surfaces. The aim of this work is to develop the fundamental physical and chemical understanding that is necessary for the development of cleanup techniques and procedures. The authors are perforrming both bulk chemical measurements of the reduction reactions and surface science studies of model chemical systems. During this first year of funding, the authors have already made significant progress in both areas. Initially, they have focused primarily on the reduction of selenate by elemental iron. They have also performed some work with chromate, perchlorate, uranyl, and carbon tetrachloride, as well. In the following sections, some of the progress is described.'

  16. Microstructural Study Of Zinc Hot Dip Galvanized Coatings with Titanium Additions In The Zinc Melt

    NASA Astrophysics Data System (ADS)

    Konidaris, S.; Pistofidis, N.; Vourlias, G.; Pavlidou, E.; Stergiou, A.; Stergioudis, G.; Polychroniadis, E. K.

    2007-04-01

    Zinc hot-dip galvanizing is a method for protecting iron and steel against corrosion. Galvanizing with pure Zn or Zn with additions like Ni, Al, Pb and Bi has been extensively studied, but there is a lack of scientific information about other additions. The present work examines the effect of a 0.5 wt% Ti addition in the Zn melt. The samples were exposed to accelerated corrosion in a salt spray chamber (SSC). The microstructure and chemical composition of the coatings were determined by Optical Microscopy, XRD and SEM associated with an EDS Analyzer. The results indicate that the coatings have a typical morphology, while Zn-Ti phases were also detected.

  17. A synchrotron study of microstructure gradient in laser additively formed epitaxial Ni-based superalloy.

    PubMed

    Xue, Jiawei; Zhang, Anfeng; Li, Yao; Qian, Dan; Wan, Jingchun; Qi, Baolu; Tamura, Nobumichi; Song, Zhongxiao; Chen, Kai

    2015-01-01

    Laser additive forming is considered to be one of the promising techniques to repair single crystal Ni-based superalloy parts to extend their life and reduce the cost. Preservation of the single crystalline nature and prevention of thermal mechanical failure are two of the most essential issues for the application of this technique. Here we employ synchrotron X-ray microdiffraction to evaluate the quality in terms of crystal orientation and defect distribution of a Ni-based superalloy DZ125L directly formed by a laser additive process rooted from a single crystalline substrate of the same material. We show that a disorientation gradient caused by a high density of geometrically necessary dislocations and resultant subgrains exists in the interfacial region between the epitaxial and stray grains. This creates a potential relationship of stray grain formation and defect accumulation. The observation offers new directions on the study of performance control and reliability of the laser additive manufactured superalloys. PMID:26446425

  18. A synchrotron study of microstructure gradient in laser additively formed epitaxial Ni-based superalloy

    SciTech Connect

    Xue, Jiawei; Zhang, Anfeng; Li, Yao; Qian, Dan; Wan, Jingchun; Qi, Baolu; Tamura, Nobumichi; Song, Zhongxiao; Chen, Kai

    2015-10-08

    Laser additive forming is considered to be one of the promising techniques to repair single crystal Ni-based superalloy parts to extend their life and reduce the cost. Preservation of the single crystalline nature and prevention of thermal mechanical failure are two of the most essential issues for the application of this technique. Here we employ synchrotron X-ray microdiffraction to evaluate the quality in terms of crystal orientation and defect distribution of a Ni-based superalloy DZ125L directly formed by a laser additive process rooted from a single crystalline substrate of the same material. We show that a disorientation gradient caused by a high density of geometrically necessary dislocations and resultant subgrains exists in the interfacial region between the epitaxial and stray grains. This creates a potential relationship of stray grain formation and defect accumulation. In conclusion, the observation offers new directions on the study of performance control and reliability of the laser additive manufactured superalloys.

  19. A synchrotron study of microstructure gradient in laser additively formed epitaxial Ni-based superalloy

    PubMed Central

    Xue, Jiawei; Zhang, Anfeng; Li, Yao; Qian, Dan; Wan, Jingchun; Qi, Baolu; Tamura, Nobumichi; Song, Zhongxiao; Chen, Kai

    2015-01-01

    Laser additive forming is considered to be one of the promising techniques to repair single crystal Ni-based superalloy parts to extend their life and reduce the cost. Preservation of the single crystalline nature and prevention of thermal mechanical failure are two of the most essential issues for the application of this technique. Here we employ synchrotron X-ray microdiffraction to evaluate the quality in terms of crystal orientation and defect distribution of a Ni-based superalloy DZ125L directly formed by a laser additive process rooted from a single crystalline substrate of the same material. We show that a disorientation gradient caused by a high density of geometrically necessary dislocations and resultant subgrains exists in the interfacial region between the epitaxial and stray grains. This creates a potential relationship of stray grain formation and defect accumulation. The observation offers new directions on the study of performance control and reliability of the laser additive manufactured superalloys. PMID:26446425

  20. Aluminum gettering of crystalline silicon for improvement of minority carrier diffusion length and for studies of fundamental diffusion mechanisms

    NASA Astrophysics Data System (ADS)

    Joshi, Subhash Mukund

    .e., the Frank-Turnbull mechanism has the dominant contribution. The fundamental physical reason for this phenomenon is identified, viz., that the diffusion mechanism that causes supersaturation of a point defect is likely to dominate over the one that causes undersaturation of the other point defect as the concentration gradient for outdiffusion of the supersaturated species is much larger than the concentration gradient for indiffusion of the undersaturated species.

  1. Fundamental studies of the plasma extraction and ion beam formation processes in inductively coupled plasma mass spectrometry

    SciTech Connect

    Niu, Hongsen

    1995-02-10

    The fundamental and practical aspects are described for extracting ions from atmospheric pressure plasma sources into an analytical mass spectrometer. Methodologies and basic concepts of inductively coupled plasma mass spectrometry (ICP-MS) are emphasized in the discussion, including ion source, sampling interface, supersonic expansion, slumming process, ion optics and beam focusing, and vacuum considerations. Some new developments and innovative designs are introduced. The plasma extraction process in ICP-MS was investigated by Langmuir measurements in the region between the skimmer and first ion lens. Electron temperature (T{sub e}) is in the range 2000--11000 K and changes with probe position inside an aerosol gas flow. Electron density (n{sub e}) is in the range 10{sup 8}--10{sup 10} {sup {minus}cm }at the skimmer tip and drops abruptly to 10{sup 6}--10{sup 8} cm{sup {minus}3} near the skimmer tip and drops abruptly to 10{sup 6}--10{sup 8} cm{sup {minus}3} downstream further behind the skimmer. Electron density in the beam leaving the skimmer also depends on water loading and on the presence and mass of matrix elements. Axially resolved distributions of electron number-density and electron temperature were obtained to characterize the ion beam at a variety of plasma operating conditions. The electron density dropped by a factor of 101 along the centerline between the sampler and skimmer cones in the first stage and continued to drop by factors of 10{sup 4}--10{sup 5} downstream of skimmer to the entrance of ion lens. The electron density in the beam expansion behind sampler cone exhibited a 1/z{sup 2} intensity fall-off (z is the axial position). An second beam expansion originated from the skimmer entrance, and the beam flow underwent with another 1/z{sup 2} fall-off behind the skimmer. Skimmer interactions play an important role in plasma extraction in the ICP-MS instrument.

  2. Summary of Previous Chamber or Controlled Anthrax Studies and Recommendations for Possible Additional Studies

    SciTech Connect

    Piepel, Gregory F.; Amidan, Brett G.; Morrow, Jayne B.

    2010-12-29

    This report and an associated Excel file(a) summarizes the investigations and results of previous chamber and controlled studies(b) to characterize the performance of methods for collecting, storing and/or transporting, extracting, and analyzing samples from surfaces contaminated by Bacillus anthracis (BA) or related simulants. This report and the Excel are the joint work of the Pacific Northwest National Laboratory (PNNL) and the National Institute of Standards and Technology (NIST) for the Department of Homeland Security, Science and Technology Directorate. The report was originally released as PNNL-SA-69338, Rev. 0 in November 2009 with limited distribution, but was subsequently cleared for release with unlimited distribution in this Rev. 1. Only minor changes were made to Rev. 0 to yield Rev. 1. A more substantial update (including summarizing data from other studies and more condensed summary tables of data) is underway

  3. Studies of levels of biogenic amines in meat samples in relation to the content of additives.

    PubMed

    Jastrzębska, Aneta; Kowalska, Sylwia; Szłyk, Edward

    2016-01-01

    The impact of meat additives on the concentration of biogenic amines and the quality of meat was studied. Fresh white and red meat samples were fortified with the following food additives: citric and lactic acids, disodium diphosphate, sodium nitrite, sodium metabisulphite, potassium sorbate, sodium chloride, ascorbic acid, α-tocopherol, propyl 3,4,5-trihydroxybenzoate (propyl gallate) and butylated hydroxyanisole. The content of spermine, spermidine, putrescine, cadaverine, histamine, tyramine, tryptamine and 2-phenylethylamine was determined by capillary isotachophoretic methods in meat samples (fresh and fortified) during four days of storage at 4°C. The results were applied to estimate the impact of the tested additives on the formation of biogenic amines in white and red meat. For all tested meats, sodium nitrite, sodium chloride and disodium diphosphate showed the best inhibition. However, cadaverine and putrescine were characterised by the biggest changes in concentration during the storage time of all the additives. Based on the presented data for the content of biogenic amines in meat samples analysed as a function of storage time and additives, we suggest that cadaverine and putrescine have a significant impact on meat quality. PMID:26515667

  4. Studies of levels of biogenic amines in meat samples in relation to the content of additives.

    PubMed

    Jastrzębska, Aneta; Kowalska, Sylwia; Szłyk, Edward

    2016-01-01

    The impact of meat additives on the concentration of biogenic amines and the quality of meat was studied. Fresh white and red meat samples were fortified with the following food additives: citric and lactic acids, disodium diphosphate, sodium nitrite, sodium metabisulphite, potassium sorbate, sodium chloride, ascorbic acid, α-tocopherol, propyl 3,4,5-trihydroxybenzoate (propyl gallate) and butylated hydroxyanisole. The content of spermine, spermidine, putrescine, cadaverine, histamine, tyramine, tryptamine and 2-phenylethylamine was determined by capillary isotachophoretic methods in meat samples (fresh and fortified) during four days of storage at 4°C. The results were applied to estimate the impact of the tested additives on the formation of biogenic amines in white and red meat. For all tested meats, sodium nitrite, sodium chloride and disodium diphosphate showed the best inhibition. However, cadaverine and putrescine were characterised by the biggest changes in concentration during the storage time of all the additives. Based on the presented data for the content of biogenic amines in meat samples analysed as a function of storage time and additives, we suggest that cadaverine and putrescine have a significant impact on meat quality.

  5. In-situ study of the influence of additives on the growth behavior of copper electrodeposits on copper single crystal

    NASA Astrophysics Data System (ADS)

    Wu, Aiwen

    Trace organic additives are known to be essential in obtaining desired metal electrodeposits in the microelectronic industry, however, fundamental design principles for their use and a scientific understanding of their interaction during electrodeposition is lacking. In the present study we investigated electrodeposition of copper on the Cu(100) surface in air-saturated or dearated acid-sulfate plating solutions containing several combinations of chloride and additives benzotriazole (BTA) and 3-mercapto propane sulfonic acid (MPSA) under galvanostatic pulse-current conditions. The electrodeposition process was followed using in-situ atomic force microscopy (AFM). AFM images were quantitatively analyzed by pattern-recognition and scaling procedures. In the absence of additives, copper deposits grew in a layer-by-layer mode from the earliest stage of deposition. The surface consisted of smooth terraces separated by steps. The scaling analysis result was consistent with a process dominated by surface diffusion and step growth. In chloride containing solutions, square-pyramidal mounds were initiated and grew to cover the surface. Mound slope increased with deposition time with no indication of reaching a steady-state value. This growth mode was consistent with a surface diffusion mechanism. The scaling result was similar to the additive-free system, but indicated that surface diffusion was more dominant in the presence of chloride. BTA inhibited the surface and produced nucleation-limited growth at hemispheroidal centers whose height to base radius aspect ratio increased linearly with deposition time. Nucleation and growth of three-dimensional nodules started randomly across the entire surface. The nodules were smaller in size than the mounds observed without BTA. The number and density of nodules were much higher than the mounds density. The deposit growth was dominated by a roughening mechanism that can be described by the random roughening term of a stochastic model

  6. A Study of Aluminum Combustion in Solids, Powders, Foams, Additively-Manufactured Lattices, and Composites

    NASA Astrophysics Data System (ADS)

    Black, James; Trammell, Norman; Batteh, Jad; Curran, Nicholas; Rogers, John; Littrell, Donald

    2015-06-01

    This study examines the fireball characteristics, blast parameters, and combustion efficiency of explosively-shocked aluminum-based materials. The materials included structural and non-structural aluminum forms - such as solid cylinders, foams, additively-manufactured lattices, and powders - and some polytetrafluoroethylene-aluminum (PTFE-Al) composites. The materials were explosively dispersed in a small blast chamber, and the blast properties and products were measured with pressure transducers, thermocouples, slow and fast ultraviolet/visible spectrometers, and high-speed video.

  7. Spectra-temporal patterns underlying mental addition: an ERP and ERD/ERS study.

    PubMed

    Ku, Yixuan; Hong, Bo; Gao, Xiaorong; Gao, Shangkai

    2010-03-12

    Functional neuroimaging data have shown that mental calculation involves fronto-parietal areas that are composed of different subsystems shared with other cognitive functions such as working memory and language. Event-related potential (ERP) analysis has also indicated sequential information changes during the calculation process. However, little is known about the dynamic properties of oscillatory networks in this process. In the present study, we applied both ERP and event-related (de-)synchronization (ERS/ERD) analyses to EEG data recorded from normal human subjects performing tasks for sequential visual/auditory mental addition. Results in the study indicate that the late positive components (LPCs) can be decomposed into two separate parts. The earlier element LPC1 (around 360ms) reflects the computing attribute and is more prominent in calculation tasks. The later element LPC2 (around 590ms) indicates an effect of number size and appears larger only in a more complex 2-digit addition task. The theta ERS and alpha ERD show modality-independent frontal and parietal differential patterns between the mental addition and control groups, and discrepancies are noted in the beta ERD between the 2-digit and 1-digit mental addition groups. The 2-digit addition (both visual and auditory) results in similar beta ERD patterns to the auditory control, which may indicate a reliance on auditory-related resources in mental arithmetic, especially with increasing task difficulty. These results coincide with the theory of simple calculation relying on the visuospatial process and complex calculation depending on the phonological process. PMID:20105450

  8. Fundamental studies of the mechanisms of slag deposit formation: Studies on initiation, growth and sintering in the formation of utility boiler deposits: Topical technical report

    SciTech Connect

    Tangsathitkulchai, M.; Austin, L.G.

    1986-03-01

    Three laboratory-scale devices were utilized to investigate the mechanisms of the initiation, growth and sintering process involved in the formation of boiler deposits. Sticking apparatus investigations were conducted to study deposit initiation by comparing the adhesion behavior of the ash drops on four types of steel-based heat exchanger materials under the conditions found in a utility boiler and an entrained slagging gasifier. In addition, the adhesion behavior of the ash drops on a reduced steel surface were investigated. All the ash drops studied in this investigation were produced from bituminous coals.

  9. STUDY OF THE FUNDAMENTALS OF MERCURY SPECIATION IN COAL-FIRED BOILERS UNDER SIMULATED POST-COMBUSTION CONDITIONS

    EPA Science Inventory

    The report discusses a continuation of the study on mercury speciation initiated in the fiscal year 1997 (FY97). The previous study found that cupric oxide (CuO) and ferric oxide (Fe2O3) in the presence of hydrogen chloride (HCl) promote elemental mercury oxidation in simulated f...

  10. A fundamental study of drag and an assessment of conventional drag-due-to-lift reduction devices

    NASA Technical Reports Server (NTRS)

    Yates, J. E.; Donald, C. D.

    1986-01-01

    The integral conservation laws of fluid mechanics are used to assess the drag efficiency of lifting wings, both CTOL and various out-of-plane configurations. The drag-due-to-lift is separated into two major components: (1) the induced drag-due-to-lift that depends on aspect ratio but is relatively independent of Reynolds number; (2) the form drag-due-to-lift that is independent of aspect ratio but dependent on the details of the wing section design, planform and Reynolds number. For each lifting configuration there is an optimal load distribution that yields the minimum value of drag-due-to-lift. For well designed high aspect ratio CTOL wings the two drag components are independent. With modern design technology CTOL wings can be (and usually are) designed with a drag-due-to-lift efficiency close to unity. Wing tip-devices (winglets, feathers, sails, etc.) can improve drag-due-to-lift efficiency by 10 to 15% if they are designed as an integral part of the wing. As add-on devices they can be detrimental. It is estimated that 25% improvements of wing drag-due-to-lift efficiency can be obtained with joined tip configurations and vertically separated lifting elements without considering additional benefits that might be realized by improved structural efficiency. It is strongly recommended that an integrated aerodynamic/structural approach be taken in the design of (or research on) future out-of-plane configurations.

  11. Fundamental studies in the molecular basis of laser-induced retinal damage. Annual report, September 1982-August 1983

    SciTech Connect

    Lewis

    1983-09-01

    This research led to major discoveries in two general areas. First, it was shown that there are a series of anionic activators of visual cells. These anionic activators turn on, in the dark, the enzymatic processes usually stimulated by light. Among these anionic activators is fluoride, the important additive in dental care. It is possible that the discovery of anionic activators will allow modulation of visual sensitivity and excitation. A second major advance was the development of a staining method that allows the direct observation with light microscopy of actin filaments in rod outer segments. This discovery will now allow viewing these important actin filaments in live cells under physiologically relevant experimental conditions. It will also allow for the development of new methods to probe pathological and damaged conditions in visual photoreceptor cells. The above discoveries are described in two separate sections, the first entitled Anionic Activators of Photoreceptor Cells in the Dark, and the second entitled Visualization of Actin in Photoreceptor Cells by Light Microscopy.

  12. Variation of Fundamental Constants

    NASA Astrophysics Data System (ADS)

    Flambaum, V. V.

    2006-11-01

    Theories unifying gravity with other interactions suggest temporal and spatial variation of the fundamental ``constants'' in expanding Universe. The spatial variation can explain a fine tuning of the fundamental constants which allows humans (and any life) to appear. We appeared in the area of the Universe where the values of the fundamental constants are consistent with our existence. We present a review of recent works devoted to the variation of the fine structure constant α, strong interaction and fundamental masses. There are some hints for the variation in quasar absorption spectra. Big Bang nucleosynthesis, and Oklo natural nuclear reactor data. A very promising method to search for the variation of the fundamental constants consists in comparison of different atomic clocks. Huge enhancement of the variation effects happens in transition between accidentally degenerate atomic and molecular energy levels. A new idea is to build a ``nuclear'' clock based on the ultraviolet transition between very low excited state and ground state in Thorium nucleus. This may allow to improve sensitivity to the variation up to 10 orders of magnitude! Huge enhancement of the variation effects is also possible in cold atomic and molecular collisions near Feshbach resonance.

  13. Effect of Exogenous Phytase Addition on Soil Phosphatase Activities: a Fluorescence Spectroscopy Study.

    PubMed

    Yang, Xiao-zhu; Chen, Zhen-hua; Zhang, Yu-lan; Chen, Li-jun

    2015-05-01

    The utilization of organic phosphorus (P) has directly or indirectly improved after exogenous phytase was added to soil. However, the mechanism by which exogenous phytase affected the soil phosphatases (phosphomonoesterase and phosphodiesterase) activities was not clear. The present work was aimed to study red soil, brown soil and cinnamon soil phosphomonoesterase (acid and alkaline) (AcP and AlP) and phosphodiesterase (PD) activities responding to the addition of exogenous phytase (1 g phytase/50 g air dry soil sample) based on the measurements performed via a fluorescence detection method combined with 96 microplates using a TECAN Infinite 200 Multi-Mode Microplate Reader. The results indicated that the acid phosphomonoesterase activity was significantly enhanced in red soil (p≤0. 01), while it was significantly reduced in cinnamon soil; alkaline phosphomonoesterase activity was significantly enhanced in cinnamon soil (p≤ 0. 01), while it was significantly reduced in red soil; phosphodiesterase activity was increased in three soils but it was significantly increased in brown soil (p≤0. 01) after the addition of exogenous phytase. The activities still remained strong after eight days in different soils, which indicated that exogenous phytase addition could be enhance soil phosphatases activities effectively. This effect was not only related to soil properties, such as pH and phosphorus forms, but might also be related to the excreted enzyme amount of the stimulating microorganism. Using fluorescence spectroscopy to study exogenous phytase addition influence on soil phosphatase activities was the first time at home and abroad. Compared with the conventional spectrophotometric method, the fluorescence microplate method is an accurate, fast and simple to use method to determine the relationships among the soil phosphatases activities.

  14. Competency to Study and Learn in Stressful Contests: Fundamentals of the "e-Coping with Academic Stress"™ Utility

    ERIC Educational Resources Information Center

    de la Fuente, Jesús; López, Mireia; Zapata, Lucía; Martínez-Vicente, Jose Manuel; Vera, Manuel Mariano; Solinas, Giulliana; Fadda, Salvatore

    2014-01-01

    There has been growing research interest in achievement emotions in university teaching-learning processes in recent years. While their importance has been firmly established, there continues to be a need for assessment and intervention models. The objective of this report is to present the "Competency Model for Studying, Learning and…

  15. Monte Carlo fundamentals

    SciTech Connect

    Brown, F.B.; Sutton, T.M.

    1996-02-01

    This report is composed of the lecture notes from the first half of a 32-hour graduate-level course on Monte Carlo methods offered at KAPL. These notes, prepared by two of the principle developers of KAPL`s RACER Monte Carlo code, cover the fundamental theory, concepts, and practices for Monte Carlo analysis. In particular, a thorough grounding in the basic fundamentals of Monte Carlo methods is presented, including random number generation, random sampling, the Monte Carlo approach to solving transport problems, computational geometry, collision physics, tallies, and eigenvalue calculations. Furthermore, modern computational algorithms for vector and parallel approaches to Monte Carlo calculations are covered in detail, including fundamental parallel and vector concepts, the event-based algorithm, master/slave schemes, parallel scaling laws, and portability issues.

  16. Arguing against fundamentality

    NASA Astrophysics Data System (ADS)

    McKenzie, Kerry

    This paper aims to open up discussion on the relationship between fundamentality and naturalism, and in particular on the question of whether fundamentality may be denied on naturalistic grounds. A historico-inductive argument for an anti-fundamentalist conclusion, prominent within the contemporary metaphysical literature, is examined; finding it wanting, an alternative 'internal' strategy is proposed. By means of an example from the history of modern physics - namely S-matrix theory - it is demonstrated that (1) this strategy can generate similar (though not identical) anti-fundamentalist conclusions on more defensible naturalistic grounds, and (2) that fundamentality questions can be empirical questions. Some implications and limitations of the proposed approach are discussed.

  17. Analysis, scientific computing and fundamental studies in fluid mechanics. Summary report number 19, May 1, 1995--April 30, 1996

    SciTech Connect

    1996-07-01

    Summaries are given of the progress on each of the following research projects: (1) a multi-resolution finite element method for computing multiscale solutions; (2) numerical study of free interface problems; (3) numerical simulation of two-dimensional particle coarsening; (4) numerical simulation of three-dimensional water waves; (5) vortex dynamics; (6) vortex models and turbulence; (7) flow in a non-uniform Hele-Shaw cell; (8) numerical analysis/scientific computing.

  18. Fundamental Study of a Jet-in-Cross-Flow Interacting with a Vortex Generator for Film Cooling Applications

    NASA Technical Reports Server (NTRS)

    Zaman, Khairul; Rigby, David; Heidmann, James

    2009-01-01

    Results of an experimental study are presented on the effectiveness of a vortex generator (VG) in preventing lift-off of a jet-in-cross-flow (JICF). The study is pertinent to film-cooling applications and its relevance to NASA programs is first briefly discussed. In the experiment, the jet issues into the boundary layer at an angle of 20deg to the free-stream. The effect of a triangular, ramp-shaped VG is studied while varying its geometry and location. Detailed flow-field properties are obtained for a case in which the height of the VG and the diameter of the orifice are comparable to the approach boundary layer thickness. The VG produces a streamwise vortex pair with vorticity magnitude three times larger (and of opposite sense) than that found in the JICF alone. Such a VG appears to be most effective in keeping the jet attached to the wall. The effect of parametric variation is studied mostly from surveys ten diameters downstream from the orifice. Results over a range of jet-to-freestream momentum flux ratio (1

  19. Fundamental and exploratory studies of catalytic steam gasification of carbonaceous materials. Final report, fiscal years 1985--1994

    SciTech Connect

    Heinemann, H.; Somorjai, G.A.

    1994-03-01

    The major purpose of this project was to find catalysts which will permit steam gasification of carbonaceous material at reasonable rates and at lower temperatures than currently practiced. Rapid catalyst deactivation must be avoided. An understanding of the catalytic mechanism is necessary to provide leads towards this aim. This report describes the gasification of graphite studies and the gasification of coals, chars, and petroleum cokes.

  20. Fundamental studies of fuel chemistry as related to internal combustion engine phenomena. Final technical report, October 1987--December 1989

    SciTech Connect

    Dryer, F.L.; Brezinsky, K.

    1990-09-01

    Intent of this research effort was to provide insight (through homogeneous gas phase kinetic studies at different constant pressures) to the fuel chemistry issues important to autoignition in engines. Conditions of the proposed experiments were chosen to be similar to engine parameters under knocking conditions: 700--1100 K temperatures, 1--20 atm pressures, and stoichiometries around 1. A variable pressure flow reactor was designed in which a range of reaction pressures and lower reaction temperatures could be accessed. Crossed beam optical access, continuous on-line gas sampling (nondispersive infrared, oxygen paramagnetic, H thermo-conductive, Fourier transform infrared, off-line GC, GC/mass spectrometric, wet chemical), and temperature measurements at the sampling location are available; reacting systems with reaction times ranging from 50--100 ms to 15--20 s can be studied. Testing has begun. Experiments on isobutene/oxygen mixtures have been conducted in the old atmospheric pressure flow reactor at 1150 K and in an equivalence ratio range of pyrolysis with 100 ppM oxygen background to 0.42. The kinetic model indicates that the inhibitory effect of isobutene at high temps is due to depletion of the active radical pool and formation of unreactive stable species and methyl radicals; isobutene oxidation/pyrolysis is heavily influenced by the chemistry of methyl radicals. The reaction of hydroperoxy radical (HO{sub 2}) with methyl radical and its effect on isobutene oxidation will be studied in the new reactor.

  1. Fundamentals of fluid lubrication

    NASA Technical Reports Server (NTRS)

    Hamrock, Bernard J.

    1991-01-01

    The aim is to coordinate the topics of design, engineering dynamics, and fluid dynamics in order to aid researchers in the area of fluid film lubrication. The lubrication principles that are covered can serve as a basis for the engineering design of machine elements. The fundamentals of fluid film lubrication are presented clearly so that students that use the book will have confidence in their ability to apply these principles to a wide range of lubrication situations. Some guidance on applying these fundamentals to the solution of engineering problems is also provided.

  2. Fundamentals of fluid sealing

    NASA Technical Reports Server (NTRS)

    Zuk, J.

    1976-01-01

    The fundamentals of fluid sealing, including seal operating regimes, are discussed and the general fluid-flow equations for fluid sealing are developed. Seal performance parameters such as leakage and power loss are presented. Included in the discussion are the effects of geometry, surface deformations, rotation, and both laminar and turbulent flows. The concept of pressure balancing is presented, as are differences between liquid and gas sealing. Mechanisms of seal surface separation, fundamental friction and wear concepts applicable to seals, seal materials, and pressure-velocity (PV) criteria are discussed.

  3. Fundamental neutron physics at LANSCE

    SciTech Connect

    Greene, G.

    1995-10-01

    Modern neutron sources and science share a common origin in mid-20th-century scientific investigations concerned with the study of the fundamental interactions between elementary particles. Since the time of that common origin, neutron science and the study of elementary particles have evolved into quite disparate disciplines. The neutron became recognized as a powerful tool for studying condensed matter with modern neutron sources being primarily used (and justified) as tools for neutron scattering and materials science research. The study of elementary particles has, of course, led to the development of rather different tools and is now dominated by activities performed at extremely high energies. Notwithstanding this trend, the study of fundamental interactions using neutrons has continued and remains a vigorous activity at many contemporary neutron sources. This research, like neutron scattering research, has benefited enormously by the development of modern high-flux neutron facilities. Future sources, particularly high-power spallation sources, offer exciting possibilities for continuing this research.

  4. A synchrotron study of microstructure gradient in laser additively formed epitaxial Ni-based superalloy

    DOE PAGES

    Xue, Jiawei; Zhang, Anfeng; Li, Yao; Qian, Dan; Wan, Jingchun; Qi, Baolu; Tamura, Nobumichi; Song, Zhongxiao; Chen, Kai

    2015-10-08

    Laser additive forming is considered to be one of the promising techniques to repair single crystal Ni-based superalloy parts to extend their life and reduce the cost. Preservation of the single crystalline nature and prevention of thermal mechanical failure are two of the most essential issues for the application of this technique. Here we employ synchrotron X-ray microdiffraction to evaluate the quality in terms of crystal orientation and defect distribution of a Ni-based superalloy DZ125L directly formed by a laser additive process rooted from a single crystalline substrate of the same material. We show that a disorientation gradient caused bymore » a high density of geometrically necessary dislocations and resultant subgrains exists in the interfacial region between the epitaxial and stray grains. This creates a potential relationship of stray grain formation and defect accumulation. In conclusion, the observation offers new directions on the study of performance control and reliability of the laser additive manufactured superalloys.« less

  5. Couples Counseling in Alzheimer's Disease: Additional Clinical Findings from a Novel Intervention Study.

    PubMed

    Auclair, Ursula; Epstein, Cynthia; Mittelman, Mary

    2009-04-01

    This article describes the clinical findings of a study designed to assess the benefit of counseling for couples, one of whom is in the early stage of Alzheimer's disease (AD). We previously reported our findings based on the first 12 couples that enrolled in the study. Based on the treatment of 30 additional couples, we have refined our treatment strategy to include concepts of Gestalt Therapy and Transactional Analysis and identified prevalent issues of concern to this cohort. The study design has remained as described in the earlier article (Epstein et al., 2006), and has proven to be appropriate to meet the goals of this intervention as indicated by our clinical experience and feedback from the participating couples. Case vignettes demonstrate how to conduct the sessions so that the experience of each member of the dyad is validated, while acknowledging the differential impact of the disease on them. PMID:19865591

  6. Fundamental studies with a monodisperse aerosol-based liquid chromatography/mass spectrometry interface (MAGIC-LC/MS). Final progress report, December 1, 1989--December 31, 1992

    SciTech Connect

    Browner, R.F.

    1992-12-01

    One of the most dramatic developments in mass spectrometry in the last fifteen years has been the evolution of versatile and powerful interfacing approaches that allow direct chromatographic coupling of separations techniques to mass spectrometers. The most successful of these approaches have been aerosol-based. This report describes the research carried out under DOE support directed toward fundamental studies with the Particle Beam LC/MS interface (also known as the MAGIC LC/MS interface). The primary goal has been to gain a better understanding of aerosol generation, transport, vaporization, and ionization processes which forms the basis of the technique. Gaining a deeper understanding of the basic physical processes on which particle Beam LC/MS is based provides the most direct way to improve performance benchmarks, such as (1) detection limits (2) quality of mass spectra (3) range of compound types possible, and (4) the ability to interface with all types of separation techniques. This research effort has been devoted to developing a fundamental understanding of the basic physical process which underlie aerosol mass spectrometry interfacing approaches. The paper describes chromatographic peak broadening studies and carrier effects with the particle beam interface.

  7. Fundamental studies of stress distributions and stress relaxation in oxide scales on high temperature alloys. [Final progress report

    SciTech Connect

    Shores, D.A.; Stout, J.H.; Gerberich, W.W.

    1993-06-01

    This report summarizes a three-year study of stresses arising in the oxide scale and underlying metal during high temperature oxidation and of scale cracking. In-situ XRD was developed to measure strains during oxidation over 1000{degrees}C on pure metals. Acoustic emission was used to observe scale fracture during isothermal oxidation and cooling, and statistical analysis was used to infer mechanical aspects of cracking. A microscratch technique was used to measure the fracture toughness of scale/metal interface. A theoretical model was evaluated for the development and relaxation of stresses in scale and metal substrate during oxidation.

  8. [Fundamental studies in oxidation-reduction in relation to water photolysis]. Final report, February 15, 1990--July 31, 1993

    SciTech Connect

    Hurst, J.K.

    1994-07-01

    Broad objectives are to improve the conceptual view of ways in which membranes and interfaces can be used to control chemical reactivity. Focus was on three elementary processes central to developing membrane-based integrated chemical systems for water photolysis or related photoconversion/photostorage processes. It was sought to identify the influence of interfaces on charge separation/recombination reactions, pathways for transmembrane charge separation across hydrocarbon bilayer membranes, and mechanisms of water oxidation catalyzed by transition metal coordination complexes. The supramolecular assemblies studied comprise primarily small unilamellar vesicles doped with amphiphilic viologens (N,N`dialkyl-4,4`-bipyridinium ions) which can function as transmembrane charge relays.

  9. Addition of fluoride to pit and fissure sealants--a feasibility study.

    PubMed

    Swartz, M L; Phillips, R W; Norman, R D; Elliason, S; Rhodes, B F; Clark, H E

    1976-01-01

    The data obtained in this in vitro study indicate that contact with pit and fissure sealants to which NaF has been added in amounts ranging from 2 to 5% substantially increases the fluoride content of the enamel and reduces its solubility in acid. The properties of the materials do not seem to be impaired by the addition of fluoride in these amounts. It thus appears that this approach to providing a backup anticariogenic mechanism may, indeed, be feasible. However, further investigation must be done to confirm the anticariogenic effect and to establish the most efficacious means of fluoride incorporation in the materials.

  10. Fundamental study for improvement of dewatering of fine coal/refuse. Annual report, August 1982-August 1983

    SciTech Connect

    Chiang, S.H.; Klinzing, G.E.; Morsi, B.J.; Tierney, J.W.; Adams, J.; Bhat, N.; Binkley, T.; Chi, S.M.; Kakwani, R.; Qamar, I.

    1983-09-01

    The overall objective of the study is to seek improved methods of dewatering through a better understanding of the filtration and post-filtration processes. As a first step, efforts have been focused on the mechanism of dewatering in terms of basic properties of coal (and refuse) particles and microstructures of filter cakes, and their relations to filtration rate and final moisture content. Pittsburgh seam-Bruceton Mine coal was used as a base coal with experiments also being conducted with Upper Freeport and Illinois No. 6 coals. During the past year, filter cakes from the above coals with widely varied size ranges were micrographically characterized. The effects of a number of surface active agents and of entrapped air bubbles on the filter cake properties were also studied. A module of the network model for calculating single phase permeabilities was completed and tested. The report is divided into four parts: summary and deliverables; work forecast for the 1983-84; detailed descriptions of technical progress for particle/filter cake characterization; theoretical modeling, and enhanced dewatering methods; and appendices. 11 references, 35 figures, 11 tables.

  11. Fundamental Studies of Low Velocity Impact Resistance of Graphite Fiber Reinforced Polymer Matrix Composites. Ph.D. Thesis

    NASA Technical Reports Server (NTRS)

    Bowles, K. J.

    1985-01-01

    A study was conducted to relate the impact resistance of graphite fiber reinforced composites with matrix properties through gaining an understanding of the basic mechanics involved in the deformation and fracture process, and the effect of the polymer matrix structure on these mechanisms. It was found that the resin matrix structure influences the composite impact resistance in at least two ways. The integration of flexibilizers into the polymer chain structure tends to reduce the T sub g and the mechanical properties of the polymer. The reduction in the mechanical properties of the matrix does not enhance the composite impact resistance because it allows matrix controlled failure to initiate impact damage. It was found that when the instrumented dropweight impact tester is used as a means for assessing resin toughness, the resin toughness is enhanced by the ability of the clamped specimen to deflect enough to produce sufficient membrane action to support a significant amount of the load. The results of this study indicate that crossplied composite impact resistance is very much dependent on the matrix mechanical properties.

  12. Fundamental study on transient bubble (slug) behavior by characterizing transient forces of solid particles in fluidized beds

    SciTech Connect

    Kono, H.O.

    1991-01-01

    The objective of this work is to recognize and interpret the signals of transient motion of bubbles (slugs) in fluidized beds by measuring and utilizing the signals of transient motion of solid particles. The two signals were measured simultaneously and also synchronized by using the TTL signal technique in the same fluidized beds. Also, a simultaneous study of video bubble image, transient force and pressure signals was initiated in a two dimensional fluidized bed. we successfully synchronized three signals so that the relationship of bubble behavior and force pressure signals can be identified and characterized. It has been found that bubble image can well be correlated to the transient force signal of solid particles under certain conditions in three dimensional fluidized beds. Accordingly, it seems that the transient force signals can significantly help understanding the transient motion of bubbles (slugs), which is important to design the fluidized beds.

  13. Fundamental study on transient bubble (slug) behavior by characterizing transient forces of solid particles in fluidized beds. 1990 Annual report

    SciTech Connect

    Kono, H.O.

    1991-01-01

    The objective of this work is to recognize and interpret the signals of transient motion of bubbles (slugs) in fluidized beds by measuring and utilizing the signals of transient motion of solid particles. The two signals were measured simultaneously and also synchronized by using the TTL signal technique in the same fluidized beds. Also, a simultaneous study of video bubble image, transient force and pressure signals was initiated in a two dimensional fluidized bed. we successfully synchronized three signals so that the relationship of bubble behavior and force pressure signals can be identified and characterized. It has been found that bubble image can well be correlated to the transient force signal of solid particles under certain conditions in three dimensional fluidized beds. Accordingly, it seems that the transient force signals can significantly help understanding the transient motion of bubbles (slugs), which is important to design the fluidized beds.

  14. Substrate Selection for Fundamental Studies of Electrocatalysts and Photoelectrodes: Inert Potential Windows in Acidic, Neutral, and Basic Electrolyte

    PubMed Central

    Gorlin, Yelena; Jaramillo, Thomas F.

    2014-01-01

    The selection of an appropriate substrate is an important initial step for many studies of electrochemically active materials. In order to help researchers with the substrate selection process, we employ a consistent experimental methodology to evaluate the electrochemical reactivity and stability of seven potential substrate materials for electrocatalyst and photoelectrode evaluation. Using cyclic voltammetry with a progressively increased scan range, we characterize three transparent conducting oxides (indium tin oxide, fluorine-doped tin oxide, and aluminum-doped zinc oxide) and four opaque conductors (gold, stainless steel 304, glassy carbon, and highly oriented pyrolytic graphite) in three different electrolytes (sulfuric acid, sodium acetate, and sodium hydroxide). We determine the inert potential window for each substrate/electrolyte combination and make recommendations about which materials may be most suitable for application under different experimental conditions. Furthermore, the testing methodology provides a framework for other researchers to evaluate and report the baseline activity of other substrates of interest to the broader community. PMID:25357131

  15. Substrate selection for fundamental studies of electrocatalysts and photoelectrodes: inert potential windows in acidic, neutral, and basic electrolyte.

    PubMed

    Benck, Jesse D; Pinaud, Blaise A; Gorlin, Yelena; Jaramillo, Thomas F

    2014-01-01

    The selection of an appropriate substrate is an important initial step for many studies of electrochemically active materials. In order to help researchers with the substrate selection process, we employ a consistent experimental methodology to evaluate the electrochemical reactivity and stability of seven potential substrate materials for electrocatalyst and photoelectrode evaluation. Using cyclic voltammetry with a progressively increased scan range, we characterize three transparent conducting oxides (indium tin oxide, fluorine-doped tin oxide, and aluminum-doped zinc oxide) and four opaque conductors (gold, stainless steel 304, glassy carbon, and highly oriented pyrolytic graphite) in three different electrolytes (sulfuric acid, sodium acetate, and sodium hydroxide). We determine the inert potential window for each substrate/electrolyte combination and make recommendations about which materials may be most suitable for application under different experimental conditions. Furthermore, the testing methodology provides a framework for other researchers to evaluate and report the baseline activity of other substrates of interest to the broader community.

  16. FUNDAMENTAL STUDY ON REAL-TIME FLOOD FORECASTING METHOD FOR LOCALLY HEAVY RAINFALL IN URBAN DRAINAGE AREAS

    NASA Astrophysics Data System (ADS)

    Kimura, Makoto; Kido, Yoshinobu; Nakakita, Eiichi

    Recently, locally heavy rainfall occurs frequently at highly urbanized area, and causes serious personal accidents, so importance of flood forecasting system is growing in order to reduce damage of inundation. However, flood forecasting that secured lead-time for evacuation is extremely difficult, because the rainfall flows out rapidly. In this study, the numerical simulation model that can finely express inundation mechanism of urban drainage areas was applied with the most recent available data and analysis tool. The influence of the factor (i.e. sewer system, overland and rainfall information) which affected inundation mechanism was evaluated through the sensibility analysis with this model, and evaluation results show some requirements of model condition and information on time and space resolution of real-time flood forecasting.

  17. Coprocessing through fundamental and mechanistic studies in hydrogen transfer and catalysis. Quarterly report, December 27, 1991--March 27, 1992

    SciTech Connect

    Curtis, C.W.

    1992-12-31

    The research conducted this quarter evaluated hydrogen transfer from resids reduced using the Birch reduction method and their corresponding parent resid to an aromatic acceptor, anthracene (ANT). The reactions involved thermal and catalytic reactions using sulfur introduced as thiophenol. This catalyst has been shown by Rudnick to affect the hydrogen transfer from cycloalkane to aromatics/or coal. The purpose of this current study was to evaluate the efficacy of hydrogen transfer from the hydrogen-enriched reduced resid to an aromatic species and to compare that to the hydrogen transfer from the original resid. The analyses performed to evaluate hydrogen transfer were the determination of product slates from the hydrogenation of ANT and the fractionation of the resid into solubility fractions after reaction with ANT. The amount of coal conversion to THF solubles was higher in the coprocessing reactions with the reduced resids compared to the reactions with the corresponding untreated resid. The reduction of the resids by the Birch method increased the hydrogen donating ability of the resid to the same level as that obtained with the introduction of isotetralin (ISO) to the original resid. The ISO was introduced at a level of 0.5 wt % donable hydrogen. Both the original resids and the resids reduced by the Birch method were reacted in the presence of an aromatic species, anthracene (ANT). These reactions were performed under both nitrogen and hydrogen atmospheres at a pressure of 1250 psig introduced at ambient temperature. The reactions were performed both thermally and catalytically at 380{degree}C for 30 minutes. The catalyst used was thiophenol which is the same catalyst as has been used in the previously reported model compound studies involving hydrogen transfer from cycloalkanes to aromatics.

  18. Fundamental studies of materials, designs, and models development for polymer electrolyte membrane fuel cell flow field distributors

    NASA Astrophysics Data System (ADS)

    Nikam, Vaibhav Vilas

    Fuel cells are becoming a popular source of energy due to their promising performance and availability. However, the high cost of fuel cell stack forbids its deployment to end user. Moreover, bipolar plate is one of the critical components in current polymer electrolyte membrane fuel cell (PEMFC) system, causing severe increase in manufacturing cost. The objective of this research work is to develop new materials, design and manufacturing process for bipolar plates. The materials proposed for use were tested for corrosion resistance in simulated fuel cell conditions. After corrosion studies copper alloy (C17200) and Low Temperature Carburized (LTC) SS 316 were selected as an alternative material for bipolar plate. It was observed that though the copper alloy offered good resistance in corrosive atmosphere, the major advantage of using the alloys was good conductivity even after formation of corrosion layer compared to SS 316. However, LTC SS 316 achieved the best corrosion resistance (ever reported in current open literature at relatively low cost) with decreased contact resistance, as compared to SS 316. Due to the expensive and tedious machining for bipolar plate manufacturing, the conventional machining process was not used. Bipolar plates were manufactured from thin corrugated sheets formed of the alloy. This research also proposed a novel single channel convoluted flow field design which was developed by increasing the tortuosity of conventional serpentine design. The CFD model for novel single channel convoluted design showed uniform distribution of velocity over the entire three dimensional domain. The novel design was further studied using pressure drop and permeability models. These modeling calculations showed substantial benefit in using corrugated sheet design and novel single channel convoluted flow field design. All the concepts of materials (except for LTC SS 316), manufacturing and design are validated using various tests like long term stability

  19. Fundamental studies of ion injection and trapping of electrosprayed ions on a quadrupole ion trap mass spectrometer

    NASA Astrophysics Data System (ADS)

    Quarmby, Scott Thomas

    The quadrupole ion trap is a highly versatile and sensitive analytical mass spectrometer. Because of the advantages offered by the ion trap, there has been intense interest in coupling it to ionization techniques such as electrospray which form ions externally to the ion trap. In this work, experiments and computer simulations were employed to study the injection of electrosprayed ions into the ion trap of a Finnigan MAT LCQ LC/MS n mass spectrometer. The kinetic energy distribution of the ion beam was characterized and found to be relatively wide, a result of the high pressures from the atmospheric pressure source. One of the most important experimental parameters which affects ion injection efficiency is the RF voltage applied to the ring electrode. A theoretical model was fit to experimental data allowing the optimum RF voltage for trapping a given m/z ion to be predicted. Computer simulations of ion motion were performed to study the effect of various instrumental parameters on trapping efficiency. A commercially available ion optics program, SIMION v6.0, was chosen because it allowed the actual ion trap electrode geometry including endcap holes to be simulated. In contrast to previous computer simulations, SIMION provided the ability to start ions outside the ion trap and to simulate more accurately the injection of externally formed ions. The endcap holes were found to allow the RF field to penetrate out of the ion trap and affect ions as they approached the ion trap. From these simulations, a model for the process by which injected ions are trapped was developed. Using these computer simulations, techniques of improving trapping efficiency were investigated. Most previous techniques perturb ions which are already in the ion trap and therefore cannot be used to accumulate ions; the ability to accumulate ions is a necessity with ionization sources such as electrospray which form ions continuously. One such novel technique for improving trapping efficiency

  20. Reading Is Fundamental, 1977.

    ERIC Educational Resources Information Center

    Smithsonian Institution, Washington, DC. National Reading is Fun-damental Program.

    Reading Is Fundamental (RIF) is a national, nonprofit organization designed to motivate children to read by making a wide variety of inexpensive books available to them and allowing the children to choose and keep books that interest them. This annual report for 1977 contains the following information on the RIF project: an account of the…

  1. Fundamentals of Chemical Processes.

    ERIC Educational Resources Information Center

    Moser, William R.

    1985-01-01

    Describes a course that provides students with a fundamental understanding of the chemical, catalytic, and engineering sciences related to the chemical reactions taking place in a variety of reactors of different configurations. Also describes the eight major lecture topics, course examinations, and term papers. The course schedule is included.…

  2. Unification of Fundamental Forces

    NASA Astrophysics Data System (ADS)

    Salam, Abdus; Taylor, Foreword by John C.

    2005-10-01

    Foreword John C. Taylor; 1. Unification of fundamental forces Abdus Salam; 2. History unfolding: an introduction to the two 1968 lectures by W. Heisenberg and P. A. M. Dirac Abdus Salam; 3. Theory, criticism, and a philosophy Werner Heisenberg; 4. Methods in theoretical physics Paul Adrian Maurice Dirac.

  3. Fundamentals of Diesel Engines.

    ERIC Educational Resources Information Center

    Marine Corps Inst., Washington, DC.

    This student guide, one of a series of correspondence training courses designed to improve the job performance of members of the Marine Corps, deals with the fundamentals of diesel engine mechanics. Addressed in the three individual units of the course are the following topics: basic principles of diesel mechanics; principles, mechanics, and…

  4. Fundamentals of Library Instruction

    ERIC Educational Resources Information Center

    McAdoo, Monty L.

    2012-01-01

    Being a great teacher is part and parcel of being a great librarian. In this book, veteran instruction services librarian McAdoo lays out the fundamentals of the discipline in easily accessible language. Succinctly covering the topic from top to bottom, he: (1) Offers an overview of the historical context of library instruction, drawing on recent…

  5. Homeschooling and Religious Fundamentalism

    ERIC Educational Resources Information Center

    Kunzman, Robert

    2010-01-01

    This article considers the relationship between homeschooling and religious fundamentalism by focusing on their intersection in the philosophies and practices of conservative Christian homeschoolers in the United States. Homeschooling provides an ideal educational setting to support several core fundamentalist principles: resistance to…

  6. Food Service Fundamentals.

    ERIC Educational Resources Information Center

    Marine Corps Inst., Washington, DC.

    Developed as part of the Marine Corps Institute (MCI) correspondence training program, this course on food service fundamentals is designed to provide a general background in the basic aspects of the food service program in the Marine Corps; it is adaptable for nonmilitary instruction. Introductory materials include specific information for MCI…

  7. Laser Fundamentals and Experiments.

    ERIC Educational Resources Information Center

    Van Pelt, W. F.; And Others

    As a result of work performed at the Southwestern Radiological Health Laboratory with respect to lasers, this manual was prepared in response to the increasing use of lasers in high schools and colleges. It is directed primarily toward the high school instructor who may use the text for a short course in laser fundamentals. The definition of the…

  8. Understanding the fundamentals of redox mediators in Li-O2 batteries: a case study on nitroxides.

    PubMed

    Bergner, Benjamin J; Hofmann, Christine; Schürmann, Adrian; Schröder, Daniel; Peppler, Klaus; Schreiner, Peter R; Janek, Jürgen

    2015-12-21

    The development of aprotic lithium-oxygen (Li-O2) batteries suffers from high charging overvoltages. Dissolved redox mediators, like nitroxides, providing increased energy efficiency and longer lifetime are promising tools to overcome this challenge. Since this auspicious concept is still in its infancy, the underlying chemical reactions as well as the impact of the different (electro)chemical parameters are poorly understood. Herein, we derive an electrochemical model for the charging reactions, which is validated by potentiostatic measurements. The model elucidates the impact of the major factors including basic cell parameters and the chemical properties of the redox mediator. The model is applied to the promising class of nitroxides, which is systematically investigated by using derivatives of TEMPO (2,2,6,6-tetramethyl-1-piperidinyloxy), AZADO (2-azaadamantane-N-oxyl), and an azaphenalene based nitroxide. The nitroxides are electrochemically characterized by cyclic voltammetry and their performance as redox mediators is studied in Li-O2 batteries with an ether-based electrolyte. Based on the presented model, the charging profiles of the different nitroxide redox mediators are correlated with their molecular structures.

  9. Fundamental study of application of umbilical cord mesenchymal stem cells to the periodontium to aid healing after autotransplantation of teeth.

    PubMed

    Li, Yunpeng; Hou, Rui; Wang, Yibo; Lu, Bin; Zhang, Junrui; Feng, Xinghua; Liu, Yanpu; Cao, Qiang

    2014-07-01

    After autotransplantation of teeth the healing of periodontal tissue regulates the patient's prognosis. Umbilical cord mesenchymal stem cells (UCMSC) have shown excellent pluripotent and proliferation potential. In the present study we investigated the characteristics and developmental capability of osteogenic differentiation to find out whether human UCMSC promote periodontal healing. UCMSC were obtained by primary culture and identified using flow cytometry. Flow cytometry, real-time polymerase chain reaction (PCR), Western blotting, assays of alkaline phosphatase activity, and alizarin red staining were used to assess the potential for hUCMSC to proliferate and differentiate in vitro. Both dentine and predifferentiated or undifferentiated cells were transplanted subcutaneously onto the backs of immunodeficient mice to mimic periodontal tissue healing in vivo. The result showed that hUCMSC were readily obtained, and expressed numerous mesenchymal stem cell markers. Expression of stemness markers decreased notably during osteogenic differentiation. Through investigation of different time points, we found that the osteogenic procedure could be activated and detected at day 7. In the in vivo experiments, the predifferentiated hUCMSC showed increased ability to form cementum-like deposits surrounded by fibroblast-like tissue on the surface of the dentine. In conclusion, the potential for proliferation and differentiation, and the ability to form cementum-like tissue, suggest that hUCMSC are promising candidates as a source of mesenchymal stem cell for sources of periodontal healing after autotransplantation of teeth.

  10. Understanding the fundamentals of redox mediators in Li-O2 batteries: a case study on nitroxides.

    PubMed

    Bergner, Benjamin J; Hofmann, Christine; Schürmann, Adrian; Schröder, Daniel; Peppler, Klaus; Schreiner, Peter R; Janek, Jürgen

    2015-12-21

    The development of aprotic lithium-oxygen (Li-O2) batteries suffers from high charging overvoltages. Dissolved redox mediators, like nitroxides, providing increased energy efficiency and longer lifetime are promising tools to overcome this challenge. Since this auspicious concept is still in its infancy, the underlying chemical reactions as well as the impact of the different (electro)chemical parameters are poorly understood. Herein, we derive an electrochemical model for the charging reactions, which is validated by potentiostatic measurements. The model elucidates the impact of the major factors including basic cell parameters and the chemical properties of the redox mediator. The model is applied to the promising class of nitroxides, which is systematically investigated by using derivatives of TEMPO (2,2,6,6-tetramethyl-1-piperidinyloxy), AZADO (2-azaadamantane-N-oxyl), and an azaphenalene based nitroxide. The nitroxides are electrochemically characterized by cyclic voltammetry and their performance as redox mediators is studied in Li-O2 batteries with an ether-based electrolyte. Based on the presented model, the charging profiles of the different nitroxide redox mediators are correlated with their molecular structures. PMID:26563563

  11. A water soluble additive to suppress respirable dust from concrete-cutting chainsaws: a case study.

    PubMed

    Summers, Michael P; Parmigiani, John P

    2015-01-01

    Respirable dust is of particular concern in the construction industry because it contains crystalline silica. Respirable forms of silica are a severe health threat because they heighten the risk of numerous respirable diseases. Concrete cutting, a common work practice in the construction industry, is a major contributor to dust generation. No studies have been found that focus on the dust suppression of concrete-cutting chainsaws, presumably because, during normal operation water is supplied continuously and copiously to the dust generation points. However, there is a desire to better understand dust creation at low water flow rates. In this case study, a water-soluble surfactant additive was used in the chainsaw's water supply. Cutting was performed on a free-standing concrete wall in a covered outdoor lab with a hand-held, gas-powered, concrete-cutting chainsaw. Air was sampled at the operator's lapel, and around the concrete wall to simulate nearby personnel. Two additive concentrations were tested (2.0% and 0.2%), across a range of fluid flow rates (0.38-3.8 Lpm [0.1-1.0 gpm] at 0.38 Lpm [0.1 gpm] increments). Results indicate that when a lower concentration of additive is used exposure levels increase. However, all exposure levels, once adjusted for 3 hours of continuous cutting in an 8-hour work shift, are below the Occupational Safety and Health Administration (OSHA) permissible exposure limit (PEL) of 5 mg/m(3). Estimates were made using trend lines to predict the fluid flow rates that would cause respirable dust exposure to exceed both the OSHA PEL and the American Conference of Governmental Industrial Hygienists (ACGIH®) threshold limit value (TLV).

  12. Maximum Entropy Fundamentals

    NASA Astrophysics Data System (ADS)

    Harremoeës, P.; Topsøe, F.

    2001-09-01

    In its modern formulation, the Maximum Entropy Principle was promoted by E.T. Jaynes, starting in the mid-fifties. The principle dictates that one should look for a distribution, consistent with available information, which maximizes the entropy. However, this principle focuses only on distributions and it appears advantageous to bring information theoretical thinking more prominently into play by also focusing on the "observer" and on coding. This view was brought forward by the second named author in the late seventies and is the view we will follow-up on here. It leads to the consideration of a certain game, the Code Length Game and, via standard game theoretical thinking, to a principle of Game Theoretical Equilibrium. This principle is more basic than the Maximum Entropy Principle in the sense that the search for one type of optimal strategies in the Code Length Game translates directly into the search for distributions with maximum entropy. In the present paper we offer a self-contained and comprehensive treatment of fundamentals of both principles mentioned, based on a study of the Code Length Game. Though new concepts and results are presented, the reading should be instructional and accessible to a rather wide audience, at least if certain mathematical details are left aside at a rst reading. The most frequently studied instance of entropy maximization pertains to the Mean Energy Model which involves a moment constraint related to a given function, here taken to represent "energy". This type of application is very well known from the literature with hundreds of applications pertaining to several different elds and will also here serve as important illustration of the theory. But our approach reaches further, especially regarding the study of continuity properties of the entropy function, and this leads to new results which allow a discussion of models with so-called entropy loss. These results have tempted us to speculate over the development of natural

  13. Sediment Studies Refute EIS Hypothesis, While Most Fundamental Process Questions Remain Unanswered: An Update on Experiments in Grand Canyon

    NASA Astrophysics Data System (ADS)

    Melis, T. S.; Topping, D. J.; Wright, S. A.; Rubin, D. M.; Schmidt, J. C.; Hazel, J. E.; Kaplinski, M. A.; Parnell, R. A.

    2004-12-01

    drought throughout the Upper Colorado River Basin now poses a natural barrier to testing the key sediment hypothesis. Downstream sand production from the Paria River remains at its lowest level in 80 years, while water storage in Lake Powell approaches 40 percent of capacity. As scientists wait out delays in sediment experimentation forced by the current drought, managers have already approved limited sediment augmentation feasibility studies aimed at identifying options for managing physical habitats. With regard to conventional thinking about regulation and management of natural hydrologic systems, some important lessons may be learned from the current situation. Rubin, D.M., Topping, D.J., Schmidt, J.C., Hazel, J., Kaplinski, M. and Melis, T.S., 2002, Recent Sediment Studies Refute Glen Canyon Dam EIS Hypothesis: Eos, vol. 83, no. 25, p. 273-278. Laursen, E.M., Ince, S. and Pollack, J., 1976, On Sediment Transport Through the Grand Canyon, Proceedings of the 3rd Federal Interagency Sedimentation Conference, Denver, CO, vol. 1, p. 4-76 - 4-87.

  14. Fundamental study on photodynamic therapy for atrial fibrillation: effect of photosensitization reaction parameters on myocardial necrosis in vitro

    NASA Astrophysics Data System (ADS)

    Ogawa, Emiyu; Ito, Arisa; Arai, Tsunenori

    2012-03-01

    We studied necrotic cell death effect on myocardial cells with photosensitizer existed outside the cells varying photosensitization reaction parameters widely in vitro. We have developed non-thermal ablator with the application of photosensitization reaction for atrial fibrillation. Since laser irradiation is applied shortly after photosensitizer injection, the photosensitization reaction is induced outside the cells. The interaction for the myocardial cells by the photosensitization reaction is not well understood yet on various photosensitization reaction parameters. Rat myocardial cells were cultured in 96 well plates for 7 days. The photosensitization reaction was applied with talaporfin sodium (NPe6) and the semiconductor laser of 663nm wavelength. The average drug light interval was set 8 mins. The photosensitizer concentration and radiant exposure were varied from 5 to 40 μg/ml and 1.2 to 60 J/cm2, respectively. The well bottom was irradiated by the red laser with irradiance of 293 mW/cm2. The photosensitizer fluorescence was monitored during the photosensitization reaction. Alive cell rate was measured by WST assay after 2 hours from the irradiation. In the case of the photosensitizer concentration of 10 μg/ml, the myocardial cells were almost alive even thought 60 J/cm2 in the radiant exposure was applied. In the 15 μg/ml case, the alive cell rate was almost linear relation to the photosensitizer concentration and radiant exposure. We obtained that the threshold for myocardial cell necrosis on the photosensitizer concentration was around 15 μg/ml with 20 J/cm2 in the radiant exposure. This threshold on the photosensitizer concentration was similar to the reported threshold for cancer therapy.

  15. Fundamental Study of Detection of Muscle Hypertrophy-Oriented Gene Doping by Myostatin Knock Down Using RNA Interference

    PubMed Central

    Takemasa, Tohru; Yakushiji, Naohisa; Kikuchi, Dale Manjiro; Deocaris, Custer; Widodo; Machida, Masanao; Kiyosawa, Hidenori

    2012-01-01

    To investigate the feasibility of developing a method for detection of gene doping in power-athletes, we devised an experimental model system. Myostatin is a potent negative regulator of skeletal muscle development and growth, and myostatin-knockout mice exhibit a double-muscle phenotype. To achieve knockdown, we constructed plasmids expressing short hairpin interfering RNAs (shRNAs) against myostatin. These shRNAs were transfected into C2C12 cultured cells or injected into the tibialis anterior (TA) muscle of adult mice. By performing in vitro and in vivo experiments, we found that some shRNAs effectively reduced the expression of myostatin, and that the TA muscle showed hypertrophy of up to 27.9%. Then, using real-time PCR, we tried to detect the shRNA plasmid in the serum or muscles of mice into which it had been injected. Although we were unable to detect the plasmid in serum samples, it was detectable in the treated muscle at least four weeks after induction. We were also able to detect the plasmid in muscle in the vicinity of the TA. This gene doping model system will be useful for further studies aimed at doping control. Key pointsUsing a myostatin knockdown plasmid, we have succeeded in creating a model system for gene doping using mice that resulted in muscle hypertrophy greater than that reported previously.We confirmed that there was a limit of gene doping detection using real-time PCR, either from serum or muscle smple.This model experimental system can be utilized for examining indirect methods of gene doping detection such as immune responses to gene transfer or a profiling approach using DNA microarray. PMID:24149203

  16. Fundamental and practical studies on high-performance liquid affinity chromatography of biopolymers with novel stationary phases

    SciTech Connect

    Bacolod, M.D.

    1992-01-01

    Rigid microparticulate stationary phases having surface-bound metal chelating functions were developed and evaluated in high performance metal chelate affinity chromatography of proteins. Silica- and polystyrene-divinylbenzene-based metal chelate sorbents were produced in wide pore and in non-porous type of column packings. A major effort has been placed on development of non-porous highly crosslinked polystyrene-divinylbenzene (PSDVB). These PSDVB microparticles were produced by a two-step swelling polymerization, and exhibited excellent mechanical strength over a wide range of flow-rates and composition used in high performance liquid chromatography (HPLC). Simple and reproducible hydrophilic coatings were developed for the surface modification of hydrophobic PSDVB supports. A tetradentate metal chelating ligand, ethylenediamine-N, N[prime]-diacetic acid (EDDA), was covalently bound to the surface of the various supports. Sorbents having iminodiacetic acid (IDA) metal chelating functions were also evaluated. The hydrophilic character and surface coverage of various stationary phases were assessed chromatographically. Studies concerning the effects of eluent pH as well as the nature and concentration of salts on retention and selectivity with different metal chelate stationary phases having various immobilized metal ions were carried out. Elution schemes were developed for rapid separation of proteins in metal chelate affinity chromatography. EDDA stationary phases in metal forms can be viewed as complementary to IDA stationary phases since they afforded different selectivity and retentivity toward proteins. Hydrophilic PSDVB could be functionalized with IDA or EDDA metal chelating ligands or lectins. The non-porous metal chelate stationary phases afforded rapid separation of proteins by the development of multiple gradient systems, which permitted higher column peak capacity, enabling the separation of a greater number of proteins in a single chromatographic run.

  17. Fundamental studies of methanol synthesis from CO(2) hydrogenation on Cu(111), Cu clusters, and Cu/ZnO(0001).

    PubMed

    Yang, Yixiong; Evans, Jaime; Rodriguez, Jose A; White, Michael G; Liu, Ping

    2010-09-01

    A combination of experimental and theoretical methods were employed to investigate the synthesis of methanol via CO(2) hydrogenation (CO(2) + 3H(2)--> CH(3)OH + H(2)O) on Cu(111) and Cu nanoparticle surfaces. High pressure reactivity studies show that Cu nanoparticles supported on a ZnO(0001[combining macron]) single crystal exhibit a higher catalytic activity than the Cu(111) planar surface. Complementary density functional theory (DFT) calculations of methanol synthesis were also performed for a Cu(111) surface and unsupported Cu(29) nanoparticles, and the results support a higher activity for Cu nanoparticles. The DFT calculations show that methanol synthesis on Cu surfaces proceeds through a formate intermediate and the overall reaction rate is limited by both formate and dioxomethylene hydrogenation. Moreover, the superior activity of the nanoparticle is associated with its fluxionality and the presence of low-coordinated Cu sites, which stabilize the key intermediates, e.g. formate and dioxomethylene, and lower the barrier for the rate-limiting hydrogenation process. The reverse water-gas-shift (RWGS) reaction (CO(2) + H(2)--> CO + H(2)O) was experimentally observed to compete with methanol synthesis and was also considered in our DFT calculations. In agreement with experiment, the rate of the RWGS reaction on Cu nanoparticles is estimated to be approximately 2 orders of magnitude faster than methanol synthesis at T = 573 K. The experiments and calculations also indicate that CO produced by the fast RWGS reaction does not undergo subsequent hydrogenation to methanol, but instead simply accumulates as a product. Methanol production from CO hydrogenation via the RWGS pathway is hindered by the first hydrogenation of CO to formyl, which is not stable and prefers to dissociate into CO and H atoms on Cu. Our calculated results suggest that the methanol yield over Cu-based catalysts could be improved by adding dopants or promoters which are able to stabilize formyl

  18. Magneto-optical study of uranium additions to amorphous TbxFe1 - x

    NASA Astrophysics Data System (ADS)

    Dillon, J. F., Jr.; van Dover, R. B.; Hong, M.; Gyorgy, E. M.; Albiston, S. D.

    1987-02-01

    Recent reports of huge magneto-optical Kerr rotations in certain crystalline metallic uranium compounds prompted a study of the magnetic and magneto-optical effects of uranium additions to a rare-earth transition metal amorphous alloy. Using variable composition samples, the polar Kerr effect at a small spot (e.g., 0.5 mm diam) was measured as field, temperature, and composition were varied. Points on the Curie line and the edges of the compensation region were determined from these observations. The compositions studied included (TbxFe1-x)1-yUy with 0.125≤x≤0.550 and y=0.0, 0.04, 0.07, 0.16. The addition of uranium to TbxFe1-x depresses the TC of Tb-rich material much more strongly than that of Tb-poor material. The compensation region does not shift at all with increasing y. It appears that uranium does not contribute to the magnetization of these amorphous alloys, nor does it significantly affect the magneto-optical effects.

  19. Characterization studies on the additives mixed L-arginine phosphate monohydrate (LAP) crystals

    NASA Astrophysics Data System (ADS)

    Haja Hameed, A. S.; Karthikeyan, C.; Ravi, G.; Rohani, S.

    2011-04-01

    L-arginine phosphate monohydrate (LAP), potassium thiocyanate (KSCN) mixed LAP (LAP:KSCN) and sodium sulfite (Na 2SO 3) mixed LAP (LAP:Na 2SO 3) single crystals were grown by slow cooling technique. The effect of microbial contamination and coloration on the growth solutions was studied. The crystalline powders of the grown crystals were examined by X-ray diffraction and the lattice parameters of the crystals were estimated. From the FTIR spectroscopic analysis, various functional group frequencies associated with the crystals were assigned. Vickers microhardness studies were done on {1 0 0} faces for pure and additives mixed LAP crystals. From the preliminary surface second harmonic generation (SHG) results, it was found that the SHG intensity at (1 0 0) face of LAP:KSCN crystal was much stronger than that of pure LAP.

  20. The guanidine and maleic acid (1:1) complex. The additional theoretical and experimental studies

    NASA Astrophysics Data System (ADS)

    Drozd, Marek; Dudzic, Damian

    2012-04-01

    On the basis of experimental literature data the theoretical studies for guanidinium and maleic acid complex with using DFT method are performed. In these studies the experimental X-ray data for two different forms of investigated crystal were used. During the geometry optimization process one equilibrium structure was found, only. According to this result the infrared spectrum for one theoretical molecule was calculated. On the basis of potential energy distribution (PED) analysis the clear-cut assignments of observed bands were performed. For the calculated molecule with energy minimum the highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO) were obtained and graphically illustrated. The energy difference (GAP) between HOMO and LUMO was analyzed. Additionally, the nonlinear properties of this molecule were calculated. The α and β (first and second order) hyperpolarizability values are obtained. On the basis of these results the title crystal was classified as new second order NLO generator.

  1. Prazosin addition to fluvoxamine: A preclinical study and open clinical trial in OCD.

    PubMed

    Feenstra, Matthijs G P; Klompmakers, André; Figee, Martijn; Fluitman, Sjoerd; Vulink, Nienke; Westenberg, Herman G M; Denys, Damiaan

    2016-02-01

    The efficacy of selective serotonin reuptake inhibitors (SRIs) in psychiatric disorders may be "augmented" through the addition of atypical antipsychotic drugs. A synergistic increase in dopamine (DA) release in the prefrontal cortex has been suggested to underlie this augmentation effect, though the mechanism of action is not clear yet. We used in vivo microdialysis in rats to study DA release following the administration of combinations of fluvoxamine (10 mg/kg) and quetiapine (10 mg/kg) with various monoamine-related drugs. The results confirmed that the selective 5-HT1A antagonist WAY-100635 (0.05 mg/kg) partially blocked the fluvoxamine-quetiapine synergistic effect (maximum DA increase dropped from 325% to 214%). A novel finding is that the α1-adrenergic blocker prazosin (1 mg/kg), combined with fluvoxamine, partially mimicked the effect of augmentation (maximum DA increase 205%; area-under-the-curve 163%). As this suggested that prazosin augmentation might be tested in a clinical study, we performed an open clinical trial of prazosin 20 mg addition to SRI in therapy-resistant patients with obsessive-compulsive disorder applying for neurosurgery. A small, non-significant reduction in Yale Brown Obsessive Compulsive Scale (Y-BOCS) scores was observed in 10 patients and one patient was classified as a responder with a reduction in Y-BOCS scores of more than 25%. We suggest that future clinical studies augmenting SRIs with an α1-adrenergic blocker in less treatment resistant cases should be considered. The clinical trial "Prazosin in combination with a serotonin reuptake inhibitor for patients with Obsessive Compulsive disorder: an open label study" was registered at 24/05/2011 under trial number ISRCTN61562706: http://www.controlled-trials.com/ISRCTN61562706. PMID:26712326

  2. Frontiers of Fundamental Physics 14

    NASA Astrophysics Data System (ADS)

    The 14th annual international symposium "Frontiers of Fundamental Physics" (FFP14) was organized by the OCEVU Labex. It was held in Marseille, on the Saint-Charles Campus of Aix Marseille University (AMU) and had over 280 participants coming from all over the world. FFP Symposium began in India in 1997 and it became itinerant in 2004, through Europe, Canada and Australia. It covers topics in fundamental physics with the objective to enable scholars working in related areas to meet on a single platform and exchange ideas. In addition to highlighting the progress in these areas, the symposium invites the top researchers to reflect on the educational aspects of our discipline. Moreover, the scientific concepts are also discussed through philosophical and epistemological viewpoints. Several eminent scientists, such as the laureates of prestigious awards (Nobel Prize, Fields Medal,…), have already participated in these meetings. The FFP14 Symposium developed around seven main themes, namely: Astroparticle Physics, Cosmology, High Energy Physics, Quantum Gravity, Mathematical Physics, Physics Education, Epistemology and Philosophy. The morning was devoted to the plenary session, with talks for a broad audience of physicists in its first half (9:00-10:30), and more specialized in its second half (11:00-12:30); this part was held in three amphitheaters. The parallel session of the Symposium took place during the afternoon (14:30-18:30) with seven thematic conferences and an additional conference on open topics named "Frontiers of Fundamental Physics". These eight conferences were organized around the contributions of participants, in addition to the ones of invited speakers. Altogether, there were some 250 contributions to the symposium (talks and posters). The plenary talks were webcasted live and recorded. The slides of the talks and the videos of the plenary talks are available from the Symposium web site: http://ffp14.cpt.univ-mrs.fr/

  3. A combined toxicity study of zinc oxide nanoparticles and vitamin C in food additives

    NASA Astrophysics Data System (ADS)

    Wang, Yanli; Yuan, Lulu; Yao, Chenjie; Ding, Lin; Li, Chenchen; Fang, Jie; Sui, Keke; Liu, Yuanfang; Wu, Minghong

    2014-11-01

    At present, safety evaluation standards for nanofood additives are made based on the toxic effects of a single additive. Since the size, surface properties and chemical nature influence the toxicity of nanomaterials, the toxicity may have dramatically changed when nanomaterials are used as food additives in a complex system. Herein, we investigated the combined toxicity of zinc oxide nanoparticles (ZnO NPs) and vitamin C (Vc, ascorbic acid). The results showed that Vc increased the cytotoxicity significantly compared with that of the ZnO only NPs. When the cells were exposed to ZnO NPs at a concentration less than 15 mg L-1, or to Vc at a concentration less than 300 mg L-1, there was no significant cytotoxicity, both in the case of gastric epithelial cell line (GES-1) and neural stem cells (NSCs). However, when 15 mg L-1 of ZnO NPs and 300 mg L-1 of Vc were introduced to cells together, the cell viability decreased sharply indicating significant cytotoxicity. Moreover, the significant increase in toxicity was also shown in the in vivo experiments. The dose of the ZnO NPs and Vc used in the in vivo study was calculated according to the state of food and nutrition enhancer standard. After repeated oral exposure to ZnO NPs plus Vc, the injury of the liver and kidneys in mice has been indicated by the change of these indices. These findings demonstrate that the synergistic toxicity presented in a complex system is essential for the toxicological evaluation and safety assessment of nanofood.At present, safety evaluation standards for nanofood additives are made based on the toxic effects of a single additive. Since the size, surface properties and chemical nature influence the toxicity of nanomaterials, the toxicity may have dramatically changed when nanomaterials are used as food additives in a complex system. Herein, we investigated the combined toxicity of zinc oxide nanoparticles (ZnO NPs) and vitamin C (Vc, ascorbic acid). The results showed that Vc increased the

  4. Impact of contacting study authors to obtain additional data for systematic reviews: diagnostic accuracy studies for hepatic fibrosis

    PubMed Central

    2014-01-01

    Background Seventeen of 172 included studies in a recent systematic review of blood tests for hepatic fibrosis or cirrhosis reported diagnostic accuracy results discordant from 2 × 2 tables, and 60 studies reported inadequate data to construct 2 × 2 tables. This study explores the yield of contacting authors of diagnostic accuracy studies and impact on the systematic review findings. Methods Sixty-six corresponding authors were sent letters requesting additional information or clarification of data from 77 studies. Data received from the authors were synthesized with data included in the previous review, and diagnostic accuracy sensitivities, specificities, and positive and likelihood ratios were recalculated. Results Of the 66 authors, 68% were successfully contacted and 42% provided additional data for 29 out of 77 studies (38%). All authors who provided data at all did so by the third emailed request (ten authors provided data after one request). Authors of more recent studies were more likely to be located and provide data compared to authors of older studies. The effects of requests for additional data on the conclusions regarding the utility of blood tests to identify patients with clinically significant fibrosis or cirrhosis were generally small for ten out of 12 tests. Additional data resulted in reclassification (using median likelihood ratio estimates) from less useful to moderately useful or vice versa for the remaining two blood tests and enabled the calculation of an estimate for a third blood test for which previously the data had been insufficient to do so. We did not identify a clear pattern for the directional impact of additional data on estimates of diagnostic accuracy. Conclusions We successfully contacted and received results from 42% of authors who provided data for 38% of included studies. Contacting authors of studies evaluating the diagnostic accuracy of serum biomarkers for hepatic fibrosis and cirrhosis in hepatitis C patients

  5. A study of pyrazines in cigarettes and how additives might be used to enhance tobacco addiction

    PubMed Central

    Alpert, Hillel R; Agaku, Israel T; Connolly, Gregory N

    2016-01-01

    Background Nicotine is known as the drug that is responsible for the addicted behaviour of tobacco users, but it has poor reinforcing effects when administered alone. Tobacco product design features enhance abuse liability by (A) optimising the dynamic delivery of nicotine to central nervous system receptors, and affecting smokers’ withdrawal symptoms, mood and behaviour; and (B) effecting conditioned learning, through sensory cues, including aroma, touch and visual stimulation, to create perceptions of pending nicotine reward. This study examines the use of additives called ‘pyrazines’, which may enhance abuse potential, their introduction in ‘lights’ and subsequently in the highly market successful Marlboro Lights (Gold) cigarettes and eventually many major brands. Methods We conducted internal tobacco industry research using online databases in conjunction with published scientific literature research, based on an iterative feedback process. Results Tobacco manufacturers developed the use of a range of compounds, including pyrazines, in order to enhance ‘light’ cigarette products’ acceptance and sales. Pyrazines with chemosensory and pharmacological effects were incorporated in the first ‘full-flavour, low-tar’ product achieving high market success. Such additives may enhance dependence by helping to optimise nicotine delivery and dosing and through cueing and learned behaviour. Conclusions Cigarette additives and ingredients with chemosensory effects that promote addiction by acting synergistically with nicotine, increasing product appeal, easing smoking initiation, discouraging cessation or promoting relapse should be regulated by the US Food and Drug Administration. Current models of tobacco abuse liability could be revised to include more explicit roles with regard to non-nicotine constituents that enhance abuse potential. PMID:26063608

  6. A combined toxicity study of zinc oxide nanoparticles and vitamin C in food additives.

    PubMed

    Wang, Yanli; Yuan, Lulu; Yao, Chenjie; Ding, Lin; Li, Chenchen; Fang, Jie; Sui, Keke; Liu, Yuanfang; Wu, Minghong

    2014-12-21

    At present, safety evaluation standards for nanofood additives are made based on the toxic effects of a single additive. Since the size, surface properties and chemical nature influence the toxicity of nanomaterials, the toxicity may have dramatically changed when nanomaterials are used as food additives in a complex system. Herein, we investigated the combined toxicity of zinc oxide nanoparticles (ZnO NPs) and vitamin C (Vc, ascorbic acid). The results showed that Vc increased the cytotoxicity significantly compared with that of the ZnO only NPs. When the cells were exposed to ZnO NPs at a concentration less than 15 mg L(-1), or to Vc at a concentration less than 300 mg L(-1), there was no significant cytotoxicity, both in the case of gastric epithelial cell line (GES-1) and neural stem cells (NSCs). However, when 15 mg L(-1) of ZnO NPs and 300 mg L(-1) of Vc were introduced to cells together, the cell viability decreased sharply indicating significant cytotoxicity. Moreover, the significant increase in toxicity was also shown in the in vivo experiments. The dose of the ZnO NPs and Vc used in the in vivo study was calculated according to the state of food and nutrition enhancer standard. After repeated oral exposure to ZnO NPs plus Vc, the injury of the liver and kidneys in mice has been indicated by the change of these indices. These findings demonstrate that the synergistic toxicity presented in a complex system is essential for the toxicological evaluation and safety assessment of nanofood.

  7. Rate constants of hydroperoxyl radical addition to cyclic nitrones: a DFT study.

    PubMed

    Villamena, Frederick A; Merle, John K; Hadad, Christopher M; Zweier, Jay L

    2007-10-01

    Nitrones are potential synthetic antioxidants against the reduction of radical-mediated oxidative damage in cells and as analytical reagents for the identification of HO2* and other such transient species. In this work, the PCM/B3LYP/6-31+G(d,p)//B3LYP/6-31G(d) and PCM/mPW1K/6-31+G(d,p) density functional theory (DFT) methods were employed to predict the reactivity of HO2* with various functionalized nitrones as spin traps. The calculated second-order rate constants and free energies of reaction at both levels of theory were in the range of 100-103 M-1 s-1 and 1 to -12 kcal mol-1, respectively, and the rate constants for some nitrones are on the same order of magnitude as those observed experimentally. The trend in HO2* reactivity to nitrones could not be explained solely on the basis of the relationship of the theoretical positive charge densities on the nitronyl-C, with their respective ionization potentials, electron affinities, rate constants, or free energies of reaction. However, various modes of intramolecular H-bonding interaction were observed at the transition state (TS) structures of HO2* addition to nitrones. The presence of intramolecular H-bonding interactions in the transition states were predicted and may play a significant role toward a facile addition of HO2* to nitrones. In general, HO2* addition to ethoxycarbonyl- and spirolactam-substituted nitrones, as well as those nitrones without electron-withdrawing substituents, such as 5,5-dimethyl-pyrroline N-oxide (DMPO) and 5-spirocyclopentyl-pyrroline N-oxide (CPPO), are most preferred compared to the methylcarbamoyl-substituted nitrones. This study suggests that the use of specific spin traps for efficient trapping of HO2* could pave the way toward improved radical detection and antioxidant protection. PMID:17845014

  8. Additional follow-up telephone counselling and initial smoking relapse: a longitudinal, controlled study

    PubMed Central

    Wu, Lei; He, Yao; Jiang, Bin; Zuo, Fang; Liu, Qinghui; Zhang, Li; Zhou, Changxi

    2016-01-01

    Objectives Smoking cessation services can help smokers to quit; however, many smoking relapse cases occur over time. Initial relapse prevention should play an important role in achieving the goal of long-term smoking cessation. Several studies have focused on the effect of extended telephone support in relapse prevention, but the conclusions remain conflicting. Design and setting From October 2008 to August 2013, a longitudinal, controlled study was performed in a large general hospital of Beijing. Participants The smokers who sought treatment at our smoking cessation clinic were non-randomised and divided into 2 groups: face-to-face individual counselling group (FC group), and face-to-face individual counselling plus telephone follow-up counselling group (FCF group). No pharmacotherapy was offered. Outcomes The timing of initial smoking relapse was compared between FC and FCF groups. Predictors of initial relapse were investigated during the first 180 days, using the Cox proportional hazards model. Results Of 547 eligible male smokers who volunteered to participate, 457 participants (117 in FC group and 340 in FCF group) achieved at least 24 h abstinence. The majority of the lapse episodes occurred during the first 2 weeks after the quit date. Smokers who did not receive the follow-up telephone counselling (FC group) tended to relapse to smoking earlier than those smokers who received the additional follow-up telephone counselling (FCF group), and the log-rank test was statistically significant (p=0.003). A Cox regression model showed that, in the FCF group, being married, and having a lower Fagerström test score, normal body mass index and doctor-diagnosed tobacco-related chronic diseases, were significantly independent protective predictors of smoking relapse. Conclusions Within the limitations of this study, it can be concluded that additional follow-up telephone counselling might be an effective strategy in preventing relapse. Further research is still

  9. Study of mandible reconstruction using a fibula flap with application of additive manufacturing technology

    PubMed Central

    2014-01-01

    Background This study aimed to establish surgical guiding techniques for completing mandible lesion resection and reconstruction of the mandible defect area with fibula sections in one surgery by applying additive manufacturing technology, which can reduce the surgical duration and enhance the surgical accuracy and success rate. Methods A computer assisted mandible reconstruction planning (CAMRP) program was used to calculate the optimal cutting length and number of fibula pieces and design the fixtures for mandible cutting, registration, and arrangement of the fibula segments. The mandible cutting and registering fixtures were then generated using an additive manufacturing system. The CAMRP calculated the optimal fibula cutting length and number of segments based on the location and length of the defective portion of the mandible. The mandible cutting jig was generated according to the boundary surface of the lesion resection on the mandible STL model. The fibular cutting fixture was based on the length of each segment, and the registered fixture was used to quickly arrange the fibula pieces into the shape of the defect area. In this study, the mandibular lesion was reconstructed using registered fibular sections in one step, and the method is very easy to perform. Results and conclusion The application of additive manufacturing technology provided customized models and the cutting fixtures and registered fixtures, which can improve the efficiency of clinical application. This study showed that the cutting fixture helped to rapidly complete lesion resection and fibula cutting, and the registered fixture enabled arrangement of the fibula pieces and allowed completion of the mandible reconstruction in a timely manner. Our method can overcome the disadvantages of traditional surgery, which requires a long and different course of treatment and is liable to cause error. With the help of optimal cutting planning by the CAMRP and the 3D printed mandible resection jig and

  10. Damage analysis and fundamental studies

    SciTech Connect

    Not Available

    1981-02-01

    As a planning activity, the objectives of the workshop were to list, prioritize and milestone the activities necessary to understand, interpret and control the mechanical behavior of candidate fusion reactor alloys. Emphasis was placed on flow and fracture processes which are unique to the fusion environment since the national fusion materials program must evaluate these effects without assistance from other reactor programs. The working group on flow processes and properties was concerned with the time-dependent and independent flow. This included radiation hardening and steady state and cyclic creep. The working group on the effect of flow on fracture was concerned with the relationships between the unique flow properties of irradiated materials, such as dislocation channeling, and the fracture properties of these materials. The working group on time-dependent fracture was concerned with high-temperature, time-dependent fracture, such as stress-rupture and fatigue fracture, while also being concerned with time-dependent environmental effects on fracture. The working group on radiation-induced or enhanced embrittlement was concerned primarily with time-independent fracture of materials for near-term fusion device applications.

  11. Toxicogenomics concepts and applications to study hepatic effects of food additives and chemicals

    SciTech Connect

    Stierum, Rob . E-mail: stierum@voeding.tno.nl; Heijne, Wilbert; Kienhuis, Anne; Ommen, Ben van; Groten, John

    2005-09-01

    Transcriptomics, proteomics and metabolomics are genomics technologies with great potential in toxicological sciences. Toxicogenomics involves the integration of conventional toxicological examinations with gene, protein or metabolite expression profiles. An overview together with selected examples of the possibilities of genomics in toxicology is given. The expectations raised by toxicogenomics are earlier and more sensitive detection of toxicity. Furthermore, toxicogenomics will provide a better understanding of the mechanism of toxicity and may facilitate the prediction of toxicity of unknown compounds. Mechanism-based markers of toxicity can be discovered and improved interspecies and in vitro-in vivo extrapolations will drive model developments in toxicology. Toxicological assessment of chemical mixtures will benefit from the new molecular biological tools. In our laboratory, toxicogenomics is predominantly applied for elucidation of mechanisms of action and discovery of novel pathway-supported mechanism-based markers of liver toxicity. In addition, we aim to integrate transcriptome, proteome and metabolome data, supported by bioinformatics to develop a systems biology approach for toxicology. Transcriptomics and proteomics studies on bromobenzene-mediated hepatotoxicity in the rat are discussed. Finally, an example is shown in which gene expression profiling together with conventional biochemistry led to the discovery of novel markers for the hepatic effects of the food additives butylated hydroxytoluene, curcumin, propyl gallate and thiabendazole.

  12. Resources allocation in healthcare for cancer: a case study using generalised additive mixed models.

    PubMed

    Musio, Monica; Sauleau, Erik A; Augustin, Nicole H

    2012-11-01

    Our aim is to develop a method for helping resources re-allocation in healthcare linked to cancer, in order to replan the allocation of providers. Ageing of the population has a considerable impact on the use of health resources because aged people require more specialised medical care due notably to cancer. We propose a method useful to monitor changes of cancer incidence in space and time taking into account two age categories, according to healthcar general organisation. We use generalised additive mixed models with a Poisson response, according to the methodology presented in Wood, Generalised additive models: an introduction with R. Chapman and Hall/CRC, 2006. Besides one-dimensional smooth functions accounting for non-linear effects of covariates, the space-time interaction can be modelled using scale invariant smoothers. Incidence data collected by a general cancer registry between 1992 and 2007 in a specific area of France is studied. Our best model exhibits a strong increase of the incidence of cancer along time and an obvious spatial pattern for people more than 70 years with a higher incidence in the central band of the region. This is a strong argument for re-allocating resources for old people cancer care in this sub-region. PMID:23242683

  13. Covalent binding of aniline to humic substances. 2. 15N NMR studies of nucleophilic addition reactions

    USGS Publications Warehouse

    Thorn, K.A.; Pettigrew, P.J.; Goldenberg, W.S.; Weber, E.J.

    1996-01-01

    Aromatic amines are known to undergo covalent binding with humic substances in the environment. Although previous studies have examined reaction conditions and proposed mechanisms, there has been no direct spectroscopic evidence for the covalent binding of the amines to the functional groups in humic substances. In order to further elucidate the reaction mechanisms, the Suwannee River and IHSS soil fulvic and humic acids were reacted with 15N-labeled aniline at pH 6 and analyzed using 15N NMR spectrometry. Aniline underwent nucleophilic addition reactions with the quinone and other carbonyl groups in the samples and became incorporated in the form of anilinohydroquinone, anilinoquinone, anilide, imine, and heterocyclic nitrogen, the latter comprising 50% or more of the bound amine. The anilide and anilinohydroquinone nitrogens were determined to be susceptible to chemical exchange by ammonia. In the case of Suwannee River fulvic acid, reaction under anoxic conditions and pretreatment with sodium borohydride or hydroxylamine prior to reaction under oxic conditions resulted in a decrease in the proportion of anilinohydroquinone nitrogen incorporated. The relative decrease in the incorporation of anilinohydroquinone nitrogen with respect to anilinoquinone nitrogen under anoxic conditions suggested that inter- or intramolecular redox reactions accompanied the nucleophilic addition reactions.

  14. Studies on the reuse of waste printed circuit board as an additive for cement mortar.

    PubMed

    Ban, Bong-Chan; Song, Jong-Yoon; Lim, Joong-Yeon; Wang, Soo-Kyoon; An, Kwang-Guk; Kim, Dong-Su

    2005-01-01

    The recent development in electronic industries has generated a drastic increase in production of printed circuit boards (PCB). Accordingly, the amount of waste PCB from electronic productions and waste electronics and its environmental impact such as soil and groundwater contamination have become a great concern. This study aims to propose a method for reuse of waste PCB as an additive for cement mortar. Although the expansibility of waste PCB powder finer than 0.08 mm in water was observed to be greater than 2.0%, the maximum expansion rates in water for 0.08 to approximately 0.15 and 0.15 to approximately 0.30 mm sized PCB powders were less than 2.0%, which satisfied the necessary condition as an alternative additive for cement mortar in place of sand. The difference in the compressive strength of standard mortar and waste PCB added mortar was observed to be less than 10% and their difference was expected to be smaller after prolonged aging. The durability of waste PCB added cement mortar was also examined through dry/wet conditioning cyclic tests and acidic/alkaline conditioning tests. From the tests, both weight and compressive strength of cement mortar were observed to be recovered with aging. The leaching test for heavy metals from waste PCB added mortar showed that no heavy metal ions such as copper, lead, or cadmium were detected in the leachate, which resulted from fixation effect of the cement hydrates.

  15. Assessment of Nano Cellulose from Peach Palm Residue as Potential Food Additive: Part II: Preliminary Studies.

    PubMed

    Andrade, Dayanne Regina Mendes; Mendonça, Márcia Helena; Helm, Cristiane Vieira; Magalhães, Washington L E; de Muniz, Graciela Ines Bonzon; Kestur, Satyanarayana G

    2015-09-01

    High consumption of dietary fibers in the diet is related to the reduction of the risk of non-transmitting of chronic diseases, prevention of the constipation etc. Rich diets in dietary fibers promote beneficial effects for the metabolism. Considering the above and recognizing the multifaceted advantages of nano materials, there have been many attempts in recent times to use the nano materials in the food sector including as food additive. However, whenever new product for human and animal consumption is developed, it has to be tested for their effectiveness regarding improvement in the health of consumers, safety aspects and side effects. However, before it is tried with human beings, normally such materials would be assessed through biological tests on a living organism to understand its effect on health condition of the consumer. Accordingly, based on the authors' finding reported in a previous paper, this paper presents body weight, biochemical (glucose, cholesterol and lipid profile in blood, analysis of feces) and histological tests carried out with biomass based cellulose nano fibrils prepared by the authors for its possible use as food additive. Preliminary results of the study with mice have clearly brought out potential of these fibers for the said purpose. PMID:26344977

  16. Resources allocation in healthcare for cancer: a case study using generalised additive mixed models.

    PubMed

    Musio, Monica; Sauleau, Erik A; Augustin, Nicole H

    2012-11-01

    Our aim is to develop a method for helping resources re-allocation in healthcare linked to cancer, in order to replan the allocation of providers. Ageing of the population has a considerable impact on the use of health resources because aged people require more specialised medical care due notably to cancer. We propose a method useful to monitor changes of cancer incidence in space and time taking into account two age categories, according to healthcar general organisation. We use generalised additive mixed models with a Poisson response, according to the methodology presented in Wood, Generalised additive models: an introduction with R. Chapman and Hall/CRC, 2006. Besides one-dimensional smooth functions accounting for non-linear effects of covariates, the space-time interaction can be modelled using scale invariant smoothers. Incidence data collected by a general cancer registry between 1992 and 2007 in a specific area of France is studied. Our best model exhibits a strong increase of the incidence of cancer along time and an obvious spatial pattern for people more than 70 years with a higher incidence in the central band of the region. This is a strong argument for re-allocating resources for old people cancer care in this sub-region.

  17. Mechanisms on electrical breakdown strength increment of polyethylene by aromatic carbonyl compounds addition: a theoretical study.

    PubMed

    Zhang, Hui; Shang, Yan; Wang, Xuan; Zhao, Hong; Han, Baozhong; Li, Zesheng

    2013-12-01

    A theoretical investigation is accomplished on the mechanisms of electrical breakdown strength increment of polyethylene at the atomic and molecular levels. It is found that the addition of aromatic carbonyl compounds as voltage stabilizers is one of the important factors for increasing electrical breakdown strength of polyethylene, as the additives can trap hot electrons, obtain energy of hot electrons, and transform the aliphatic cation to relatively stable aromatic cation to prevent the degradation of the polyethylene matrix. The HOMO-LUMO energy gaps (E(g)), the ionization potentials (IPs), and electron affinities (EAs) at the ground states of a series of aromatic carbonyl compounds are obtained at the B3LYP/6-311+G(d,p) level. The theoretical results are in good agreement with the available experimental findings, show that 2,4-dioctyloxybenzophenone (Bzo) and 4,4'-didodecyloxybenzil (Bd) molecules can effectively increase the electrical breakdown strength when they are doped into polyethylene because of their much smaller E g values than all the other studied aromatic carbonyl molecules and excellent compatibility with polymers matrix.

  18. Fundamentals of Space Medicine

    NASA Astrophysics Data System (ADS)

    Clément, Gilles

    2005-03-01

    A total of more than 240 human space flights have been completed to date, involving about 450 astronauts from various countries, for a combined total presence in space of more than 70 years. The seventh long-duration expedition crew is currently in residence aboard the International Space Station, continuing a permanent presence in space that began in October 2000. During that time, investigations have been conducted on both humans and animal models to study the bone demineralization and muscle deconditioning, space motion sickness, the causes and possible treatment of postflight orthostatic intolerance, the changes in immune function, crew and crew-ground interactions, and the medical issues of living in a space environment, such as the effects of radiation or the risk of developing kidney stones. Some results of these investigations have led to fundamental discoveries about the adaptation of the human body to the space environment. Gilles Clément has been active in this research. This readable text presents the findings from the life science experiments conducted during and after space missions. Topics discussed in this book include: adaptation of sensory-motor, cardio-vascular, bone, and muscle systems to the microgravity of spaceflight; psychological and sociological issues of living in a confined, isolated, and stressful environment; operational space medicine, such as crew selection, training and in-flight health monitoring, countermeasures and support; results of space biology experiments on individual cells, plants, and animal models; and the impact of long-duration missions such as the human mission to Mars. The author also provides a detailed description of how to fly a space experiment, based on his own experience with research projects conducted onboard Salyut-7, Mir, Spacelab, and the Space Shuttle. Now is the time to look at the future of human spaceflight and what comes next. The future human exploration of Mars captures the imagination of both the

  19. Fundamentals of Space Medicine

    NASA Astrophysics Data System (ADS)

    Clément, G.

    2003-10-01

    As of today, a total of more than 240 human space flights have been completed, involving about 450 astronauts from various countries, for a combined total presence in space of more than 70 years. The seventh long-duration expedition crew is currently in residence aboard the International Space Station, continuing a permanent presence in space that began in October 2000. During that time, investigations have been conducted on both humans and animal models to study the bone demineralization and muscle deconditioning, space motion sickness, the causes and possible treatment of postflight orthostatic intolerance, the changes in immune function, crew and crew-ground interactions, and the medical issues of living in a space environment, such as the effects of radiation or the risk of developing kidney stones. Some results of these investigations have led to fundamental discoveries about the adaptation of the human body to the space environment. Gilles Clément has been active in this research. This book presents in a readable text the findings from the life science experiments conducted during and after space missions. Topics discussed in this book include: adaptation of sensory-motor, cardiovascular, bone and muscle systems to the microgravity of spaceflight; psychological and sociological issues of living in a confined, isolated and stressful environment; operational space medicine, such as crew selection, training and in-flight health monitoring, countermeasures and support; results of space biology experiments on individual cells, plants, and animal models; and the impact of long-duration missions such as the human mission to Mars. The author also provides a detailed description of how to fly a space experiment, based on his own experience with research projects conducted onboard Salyut-7, Mir, Spacelab, and the Space Shuttle. Now is the time to look at the future of human spaceflight and what comes next. The future human exploration of Mars captures the imagination

  20. Fundamentals of Polarized Light

    NASA Technical Reports Server (NTRS)

    Mishchenko, Michael

    2003-01-01

    The analytical and numerical basis for describing scattering properties of media composed of small discrete particles is formed by the classical electromagnetic theory. Although there are several excellent textbooks outlining the fundamentals of this theory, it is convenient for our purposes to begin with a summary of those concepts and equations that are central to the subject of this book and will be used extensively in the following chapters. We start by formulating Maxwell's equations and constitutive relations for time- harmonic macroscopic electromagnetic fields and derive the simplest plane-wave solution that underlies the basic optical idea of a monochromatic parallel beam of light. This solution naturally leads to the introduction of such fundamental quantities as the refractive index and the Stokes parameters. Finally, we define the concept of a quasi-monochromatic beam of light and discuss its implications.

  1. Study on Friction and Wear Properties of Silver Matrix Brush Material with Different Additives

    NASA Astrophysics Data System (ADS)

    Chen, Xiaoli; Wang, Wenfang; Hong, Yu; Wu, Yucheng

    2013-07-01

    Friction and wear processes of AgCuX (G, CF and AlN) composites-CuAgV alloy friction pair and effects of different additive content in silver based composite on friction and wear behavior are studied in this paper. The microstructure of the brush wear surface is observed by SEM. The results show that when graphite content is up to 9 wt.%, Ag-Cu-CF-G composite exhibits the best wear properties; when the content of aluminum nitride is up to 0.5 wt.%, Ag-Cu-AlN-G composites has the most comprehensive performance. The wear loss of both composites arises with the increase of both pressure and speed, but when speed reaches a critical value, the increased amplitude of wear loss tends to be steady.

  2. Comparative study of dimensional accuracy of different impression techniques using addition silicone impression material.

    PubMed

    Penaflor, C F; Semacio, R C; De Las Alas, L T; Uy, H G

    1998-01-01

    This study compared dimensional accuracy of the single, double with spacer, double with cut-out and double mix impression technique using addition silicone impression material. A typhodont containing Ivorine teeth model with six (6) full-crown tooth preparations were used as the positive control. Two stone replication models for each impression technique were made as test materials. Accuracy of the techniques were assessed by measuring four dimensions on the stone dies poured from the impression of the Ivorine teeth model. Results indicated that most of the measurements for the height, width and diameter slightly decreased and a few increased compared with the Ivorine teeth model. The double with cut-out and double mix technique presents the least difference from the master model as compared to the two latter impression techniques. PMID:10202524

  3. Study of cadmium, zinc and lead biosorption by orange wastes using the subsequent addition method.

    PubMed

    Pérez-Marín, A B; Ballester, A; González, F; Blázquez, M L; Muñoz, J A; Sáez, J; Zapata, V Meseguer

    2008-11-01

    The biosorption of several metals (Cd2+, Zn2+ and Pb2+) by orange wastes has been investigated in binary systems. Multicomponent sorption isotherms were obtained using an original procedure, similar to that proposed by Pagnanelli et al. [Pagnanelli, F., Petrangeli, M.P., Toro, L., Trifoni, M., Veglio, F., 2001a. Biosorption of metal ions on Arthrobacter sp.: biomass characterization and biosorption modelling. Environ. Sci. Technol. 34, 2773-2778] for monoelement systems, known as subsequent addition method (SAM). Experimental sorption data were analysed using an extended multicomponent Langmuir equation. The maximum sorption uptake was approximately 0.25mmol/g for the three binary systems studied. The reliability of the proposed procedure for obtaining the equilibrium data in binary systems was verified by means of a statistical F-test. PMID:18440805

  4. Spectroscopic studies of nucleic acid additions during seed-mediated growth of gold nanoparticles

    PubMed Central

    Tapp, Maeling; Sullivan, Rick; Dennis, Patrick; Naik, Rajesh R.

    2015-01-01

    The effect of adding nucleic acids to gold seeds during the growth stage of either nanospheres or nanorods was investigated using UV-Vis spectroscopy to reveal any oligonucleotide base or structure-specific effects on nanoparticle growth kinetics or plasmonic signatures. Spectral data indicate that the presence of DNA duplexes during seed ageing drastically accelerated nanosphere growth while the addition of single-stranded polyadenine at any point during seed ageing induces nanosphere aggregation. For seeds added to a gold nanorod growth solution, single-stranded polythymine induces a modest blue-shift in the longitudinal peak wavelength. Moreover, a particular sequence comprised of 50% thymine bases was found to induce a faster, more dramatic blue-shift in the longitudinal peak wavelength compared to any of the homopolymer incubation cases. Monomeric forms of the nucleic acids, however, do not yield discernable spectral differences in any of the gold suspensions studied. PMID:25960601

  5. Rapid identification of color additives, using the C18 cartridge: collaborative study.

    PubMed

    Young, M L

    1988-01-01

    Nine laboratories collaboratively studied a method for the separation and identification of the 7 permitted FD&C color additives (Red Nos. 3 and 40; Blue Nos. 1 and 2; Yellow Nos. 5 and 6; Green No. 3) and the banned FD&C Red No. 2 in foods. The method is based on use of a commercial C18 cartridge and spectrophotometry or thin layer chromatography. Collaborators analyzed 5 commercial products (noodles, candy, carbonated soda, flavored gelatin, and powdered drink) and 2 dye mixtures (one containing FD&C Red Nos. 2, 3, and 40; the other containing FD&C Green No. 3 and Red No. 3). All of the colors were identified with little or no difficulty by 8 collaborators. The method has been adopted official first action.

  6. Genetic assessment of additional endophenotypes from the Consortium on the Genetics of Schizophrenia Family Study.

    PubMed

    Greenwood, Tiffany A; Lazzeroni, Laura C; Calkins, Monica E; Freedman, Robert; Green, Michael F; Gur, Raquel E; Gur, Ruben C; Light, Gregory A; Nuechterlein, Keith H; Olincy, Ann; Radant, Allen D; Seidman, Larry J; Siever, Larry J; Silverman, Jeremy M; Stone, William S; Sugar, Catherine A; Swerdlow, Neal R; Tsuang, Debby W; Tsuang, Ming T; Turetsky, Bruce I; Braff, David L

    2016-01-01

    The Consortium on the Genetics of Schizophrenia Family Study (COGS-1) has previously reported our efforts to characterize the genetic architecture of 12 primary endophenotypes for schizophrenia. We now report the characterization of 13 additional measures derived from the same endophenotype test paradigms in the COGS-1 families. Nine of the measures were found to discriminate between schizophrenia patients and controls, were significantly heritable (31 to 62%), and were sufficiently independent of previously assessed endophenotypes, demonstrating utility as additional endophenotypes. Genotyping via a custom array of 1536 SNPs from 94 candidate genes identified associations for CTNNA2, ERBB4, GRID1, GRID2, GRIK3, GRIK4, GRIN2B, NOS1AP, NRG1, and RELN across multiple endophenotypes. An experiment-wide p value of 0.003 suggested that the associations across all SNPs and endophenotypes collectively exceeded chance. Linkage analyses performed using a genome-wide SNP array further identified significant or suggestive linkage for six of the candidate endophenotypes, with several genes of interest located beneath the linkage peaks (e.g., CSMD1, DISC1, DLGAP2, GRIK2, GRIN3A, and SLC6A3). While the partial convergence of the association and linkage likely reflects differences in density of gene coverage provided by the distinct genotyping platforms, it is also likely an indication of the differential contribution of rare and common variants for some genes and methodological differences in detection ability. Still, many of the genes implicated by COGS through endophenotypes have been identified by independent studies of common, rare, and de novo variation in schizophrenia, all converging on a functional genetic network related to glutamatergic neurotransmission that warrants further investigation. PMID:26597662

  7. Genetic assessment of additional endophenotypes from the Consortium on the Genetics of Schizophrenia Family Study.

    PubMed

    Greenwood, Tiffany A; Lazzeroni, Laura C; Calkins, Monica E; Freedman, Robert; Green, Michael F; Gur, Raquel E; Gur, Ruben C; Light, Gregory A; Nuechterlein, Keith H; Olincy, Ann; Radant, Allen D; Seidman, Larry J; Siever, Larry J; Silverman, Jeremy M; Stone, William S; Sugar, Catherine A; Swerdlow, Neal R; Tsuang, Debby W; Tsuang, Ming T; Turetsky, Bruce I; Braff, David L

    2016-01-01

    The Consortium on the Genetics of Schizophrenia Family Study (COGS-1) has previously reported our efforts to characterize the genetic architecture of 12 primary endophenotypes for schizophrenia. We now report the characterization of 13 additional measures derived from the same endophenotype test paradigms in the COGS-1 families. Nine of the measures were found to discriminate between schizophrenia patients and controls, were significantly heritable (31 to 62%), and were sufficiently independent of previously assessed endophenotypes, demonstrating utility as additional endophenotypes. Genotyping via a custom array of 1536 SNPs from 94 candidate genes identified associations for CTNNA2, ERBB4, GRID1, GRID2, GRIK3, GRIK4, GRIN2B, NOS1AP, NRG1, and RELN across multiple endophenotypes. An experiment-wide p value of 0.003 suggested that the associations across all SNPs and endophenotypes collectively exceeded chance. Linkage analyses performed using a genome-wide SNP array further identified significant or suggestive linkage for six of the candidate endophenotypes, with several genes of interest located beneath the linkage peaks (e.g., CSMD1, DISC1, DLGAP2, GRIK2, GRIN3A, and SLC6A3). While the partial convergence of the association and linkage likely reflects differences in density of gene coverage provided by the distinct genotyping platforms, it is also likely an indication of the differential contribution of rare and common variants for some genes and methodological differences in detection ability. Still, many of the genes implicated by COGS through endophenotypes have been identified by independent studies of common, rare, and de novo variation in schizophrenia, all converging on a functional genetic network related to glutamatergic neurotransmission that warrants further investigation.

  8. Value of Fundamental Science

    NASA Astrophysics Data System (ADS)

    Burov, Alexey

    Fundamental science is a hard, long-term human adventure that has required high devotion and social support, especially significant in our epoch of Mega-science. The measure of this devotion and this support expresses the real value of the fundamental science in public opinion. Why does fundamental science have value? What determines its strength and what endangers it? The dominant answer is that the value of science arises out of curiosity and is supported by the technological progress. Is this really a good, astute answer? When trying to attract public support, we talk about the ``mystery of the universe''. Why do these words sound so attractive? What is implied by and what is incompatible with them? More than two centuries ago, Immanuel Kant asserted an inseparable entanglement between ethics and metaphysics. Thus, we may ask: which metaphysics supports the value of scientific cognition, and which does not? Should we continue to neglect the dependence of value of pure science on metaphysics? If not, how can this issue be addressed in the public outreach? Is the public alienated by one or another message coming from the face of science? What does it mean to be politically correct in this sort of discussion?

  9. Study of triallyl phosphate as an electrolyte additive for high voltage lithium-ion cells

    NASA Astrophysics Data System (ADS)

    Xia, J.; Madec, L.; Ma, L.; Ellis, L. D.; Qiu, W.; Nelson, K. J.; Lu, Z.; Dahn, J. R.

    2015-11-01

    The role of triallyl phosphate as an electrolyte additive in Li(Ni0.42Mn0.42Co0.16)O2/graphite pouch cells was studied using ex-situ gas measurements, ultra high precision coulometry, automated storage experiments, electrochemical impedance spectroscopy, long-term cycling and X-ray photoelectron spectroscopy. Cells containing triallyl phosphate produced less gas during formation, cycling and storage than control cells. The use of triallyl phosphate led to higher coulombic efficiency and smaller charge endpoint capacity slippage during ultra high precision charger testing. Cells containing triallyl phosphate showed smaller potential drop during 500 h storage at 40 °C and 60 °C and the voltage drop decreased as the triallyl phosphate content in the electrolyte increased. However, large amounts of triallyl phosphate (>3% by weight in the electrolyte) led to large impedance after cycling and storage. Symmetric cell studies showed large amounts of triallyl phosphate (5% or more) led to significant impedance increase at both negative and positive electrodes. X-ray photoelectron spectroscopy studies suggested that the high impedance came from the polymerization of triallyl phosphate molecules which formed thick solid electrolyte interphase films at the surfaces of both negative and positive electrodes. An optimal amount of 2%-3% triallyl phosphate led to better capacity retention during long term cycling.

  10. Gas cell based on optical contacting for fundamental spectroscopy studies with initial reference absorption spectrum of H2O vapor at 1723 K and 0.0235 bar

    NASA Astrophysics Data System (ADS)

    Melin, Scott T.; Sanders, Scott T.

    2016-09-01

    A gas cell, using optically contacted sapphire windows to form a hot vapor seal, has been created for high temperature fundamental spectroscopy studies. It is designed to operate at temperatures from 280-2273 K and pressures from vacuum to 1.3 bar. Using the cell in conjunction with an external cavity diode laser spectrometer, a reference H2O vapor absorption spectrum at P=0.0235±0.0036 bar and T=1723±6 K was measured with 0.0001 cm-1 resolution over the 7326-7598 cm-1 range. Comparison of the measured spectrum to simulations reveals errors in both the HITEMP and BT2 databases. This work establishes heated static cell capabilities at temperatures well above the typical limit of approximately 1300 K set by quartz material properties. This paper addresses the design of the cell as well as the cell's limitations.

  11. Variation of fundamental constants: theory

    NASA Astrophysics Data System (ADS)

    Flambaum, Victor

    2008-05-01

    Theories unifying gravity with other interactions suggest temporal and spatial variation of the fundamental ``constants'' in expanding Universe. There are some hints for the variation of different fundamental constants in quasar absorption spectra and Big Bang nucleosynthesis data. A large number of publications (including atomic clocks) report limits on the variations. We want to study the variation of the main dimensionless parameters of the Standard Model: 1. Fine structure constant alpha (combination of speed of light, electron charge and Plank constant). 2. Ratio of the strong interaction scale (LambdaQCD) to a fundamental mass like electron mass or quark mass which are proportional to Higgs vacuum expectation value. The proton mass is propotional to LambdaQCD, therefore, the proton-to-electron mass ratio comes into this second category. We performed necessary atomic, nuclear and QCD calculations needed to study variation of the fundamental constants using the Big Bang Nucleosynthsis, quasar spectra, Oklo natural nuclear reactor and atomic clock data. The relative effects of the variation may be enhanced in transitions between narrow close levels in atoms, molecules and nuclei. If one will study an enhanced effect, the relative value of systematic effects (which are not enhanced) may be much smaller. Note also that the absolute magnitude of the variation effects in nuclei (e.g. in very narrow 7 eV transition in 229Th) may be 5 orders of magnitude larger than in atoms. A different possibility of enhancement comes from the inversion transitions in molecules where splitting between the levels is due to the quantum tunneling amplitude which has strong, exponential dependence on the electron to proton mass ratio. Our study of NH3 quasar spectra has already given the best limit on the variation of electron to proton mass ratio.

  12. The impact of bismuth addition to sequential treatment on Helicobacter pylori eradication: A pilot study.

    PubMed

    Basyigit, Sebahat; Kefeli, Ayse; Sapmaz, Ferdane; Yeniova, Abdullah Ozgür; Asilturk, Zeliha; Hokkaomeroglu, Murat; Uzman, Metin; Nazligul, Yasar

    2015-10-25

    The success of the current anti-Helicobacter pylori (H. pylori) treatment protocols is reported to decrease by years, and research is needed to strengthen the H. pylori eradication treatment. Sequential treatment (ST), one of the treatment modalities for H. pylori eradication, includes amoxicillin 1 gr b.i.d and proton pump inhibitor b.i.d for first 5 days and then includes clarithromycin 500 mg b.i.d, metronidazole 500 mg b.i.d and a proton pump inhibitor b.i.d for remaining 5 days. In this study, we investigated efficacy and tolerability of bismuth addition in to ST. We included patients that underwent upper gastrointestinal endoscopy in which H. pylori infection was diagnosed by histological examination of antral and corporal gastric mucosa biopsy. Participants were randomly administered ST or bismuth containing ST (BST) protocols for the first-line H. pylori eradication therapy. Participants have been tested by urea breath test for eradication success 6 weeks after the completion of treatment. One hundred and fifty patients (93 female, 57 male) were enrolled. There were no significant differences in eradication rates for both intention to treat population (70.2%, 95% confidence interval [CI]: 66.3-74.1% vs. 71.8%, 95% CI: 61.8-81.7%, for ST and BST, respectively, p>0.05) and per protocol population (74.6%, 95% CI: 63.2-85.8% vs. 73.7%, 95% CI: 63.9-83.5% for ST and BST, respectively, p>0.05). Despite the undeniable effect of bismuth, there may be several possible reasons of unsatisfactory eradication success. Drug administration time, coadministration of other drugs, possible H. pylori resistance to bismuth may affect the eradication success. The addition of bismuth subcitrate to ST regimen does not provide significant increase in eradication rates.

  13. Experimental Study of Disruption of Columnar Grains During Rapid Solidification in Additive Manufacturing

    NASA Astrophysics Data System (ADS)

    Manogharan, Guha; Yelamanchi, Bharat; Aman, Ronald; Mahbooba, Zaynab

    2016-03-01

    Over the years, many studies have been conducted to study and analyze the grain structures of metal alloys during additive manufacturing to improve mechanical properties. In particular, columnar grains are observed predominantly during rapid solidification of molten metal. This leads to lower mechanical properties and requires expensive secondary heat-treatment processes. This study is aimed at disrupting the formation of columnar grain growth during rapid solidification using ultrasonic vibration and analyzes the effects on grain structure and mechanical properties. A gas-metal arc welder mounted on a Rep-Rap-based low-cost metal 3 Dimension printer was used to deposit ER70S-6 mild steel layers on a plate. A contact-type ultrasonic transducer with a control system to vary the frequency and power of the vibration was used. The effects of ultrasonic vibration were determined from the statistical analysis of microstructure and micro-indentation techniques on the deposited layer and heat-affected zone. It was found that both frequency and interaction between frequency and power had significant impact on the refinement of average grain size up to 10.64% and increased the number of grains by approximately 41.78%. Analysis of micro-indentation tests showed that there was an increase of approximately 14.30% in micro-hardness due to the applied frequency during rapid solidification. A pole diagram shows that application of vibration causes randomization of grain orientation. Along with the results from this study, further efforts in modeling and experimentation of multi-directional vibrations would lead to a better understanding of disrupting columnar grains in applications that use mechanical vibrations, such as welding, directed energy deposition, brazing, etc.

  14. Evaluating the addition of positive reinforcement for learning a frightening task: a pilot study with horses.

    PubMed

    Heleski, Camie; Bauson, Laura; Bello, Nora

    2008-01-01

    Horse training often relies upon negative reinforcement (NR). This study tested the hypothesis that adding positive reinforcement (PR) to NR would enhance learning in horses (n = 34) being taught to walk over a tarp (novel/typically frightening task). Subjects were Arabians, and the same person handled all of them. This person handled half "traditionally" (NR only)--that is, halter/lead were pulled; when horse stepped forward, pressure was released; process repeated until criterion met (horse crossed the tarp with little/no obvious anxiety). The same person handled the other half traditionally--but with addition of PR < food + verbal praise > (NR + PR). Subjects "failed" the task if they refused to walk onto the tarp after 10 min. Nine horses failed; 6 of 9 failures were from NR only--no significant difference detected (p = .41). The study detected no difference in time to first crossing of the tarp (p = .30) or total time to achieve calmness criterion (p = .67). Overall, adding PR did not significantly enhance learning this task. However, there were practical implications--adding PR made the task safer/less fatiguing for the handler. PMID:18569217

  15. Evaluating the addition of positive reinforcement for learning a frightening task: a pilot study with horses.

    PubMed

    Heleski, Camie; Bauson, Laura; Bello, Nora

    2008-01-01

    Horse training often relies upon negative reinforcement (NR). This study tested the hypothesis that adding positive reinforcement (PR) to NR would enhance learning in horses (n = 34) being taught to walk over a tarp (novel/typically frightening task). Subjects were Arabians, and the same person handled all of them. This person handled half "traditionally" (NR only)--that is, halter/lead were pulled; when horse stepped forward, pressure was released; process repeated until criterion met (horse crossed the tarp with little/no obvious anxiety). The same person handled the other half traditionally--but with addition of PR < food + verbal praise > (NR + PR). Subjects "failed" the task if they refused to walk onto the tarp after 10 min. Nine horses failed; 6 of 9 failures were from NR only--no significant difference detected (p = .41). The study detected no difference in time to first crossing of the tarp (p = .30) or total time to achieve calmness criterion (p = .67). Overall, adding PR did not significantly enhance learning this task. However, there were practical implications--adding PR made the task safer/less fatiguing for the handler.

  16. Synthesis, Characterization, Molecular Modeling, and DNA Interaction Studies of Copper Complex Containing Food Additive Carmoisine Dye.

    PubMed

    Shahabadi, Nahid; Akbari, Alireza; Jamshidbeigi, Mina; Khodarahmi, Reza

    2016-06-01

    A copper complex of carmoisine dye; [Cu(carmoisine)2(H2O)2]; was synthesized and characterized by using physico-chemical and spectroscopic methods. The binding of this complex with calf thymus (ct) DNA was investigated by circular dichroism, absorption studies, emission spectroscopy, and viscosity measurements. UV-vis results confirmed that the Cu complex interacted with DNA to form a ground-state complex and the observed binding constant (2× 10(4) M(-1)) is more in keeping with the groove bindings with DNA. Furthermore, the viscosity measurement result showed that the addition of complex causes no significant change on DNA viscosity and it indicated that the intercalation mode is ruled out. The thermodynamic parameters are calculated by van't Hoff equation, which demonstrated that hydrogen bonds and van der Waals interactions played major roles in the reaction. The results of circular dichroism (CD) suggested that the complex can change the conformation of DNA from B-like form toward A-like conformation. The cytotoxicity studies of the carmoisine dye and its copper complex indicated that both of them had anticancer effects on HT-29 (colon cancer) cell line and they may be new candidates for treatment of the colon cancer.

  17. Density functional theory study of the effects of alloying additions on sulfur adsorption on nickel surfaces

    NASA Astrophysics Data System (ADS)

    Malyi, Oleksandr I.; Chen, Zhong; Kulish, Vadym V.; Bai, Kewu; Wu, Ping

    2013-01-01

    Reactions of hydrogen sulfide (H2S) with Nickel/Ytrria-doped zirconia (Ni/YDZ) anode materials might cause degradation of the performance of solid oxide fuel cells when S containing fuels are used. In this paper, we employ density functional theory to investigate S adsorption on metal (M)-doped and undoped Ni(0 0 1) and Ni(1 1 1) surfaces. Based on the performed calculations, we analyze the effects of 12 alloying additions (Ag, Au, Al, Bi, Cd, Co, Cu, Fe, Sn, Sb, V, and Zn) on the temperature of transition between clean (S atoms do not adsorb on the surfaces) and contaminated (S atoms can adsorb on the surfaces spontaneously) M-doped Ni surfaces for different concentrations of H2S in the fuel. Predicted results are consistent with many experimental studies relevant to S poisoning of both Ni/YDZ and M-doped Ni/YDZ anode materials. This study is important to understand S poisoning phenomena and to develop new S tolerant anode materials.

  18. Synthesis, Characterization, Molecular Modeling, and DNA Interaction Studies of Copper Complex Containing Food Additive Carmoisine Dye.

    PubMed

    Shahabadi, Nahid; Akbari, Alireza; Jamshidbeigi, Mina; Khodarahmi, Reza

    2016-06-01

    A copper complex of carmoisine dye; [Cu(carmoisine)2(H2O)2]; was synthesized and characterized by using physico-chemical and spectroscopic methods. The binding of this complex with calf thymus (ct) DNA was investigated by circular dichroism, absorption studies, emission spectroscopy, and viscosity measurements. UV-vis results confirmed that the Cu complex interacted with DNA to form a ground-state complex and the observed binding constant (2× 10(4) M(-1)) is more in keeping with the groove bindings with DNA. Furthermore, the viscosity measurement result showed that the addition of complex causes no significant change on DNA viscosity and it indicated that the intercalation mode is ruled out. The thermodynamic parameters are calculated by van't Hoff equation, which demonstrated that hydrogen bonds and van der Waals interactions played major roles in the reaction. The results of circular dichroism (CD) suggested that the complex can change the conformation of DNA from B-like form toward A-like conformation. The cytotoxicity studies of the carmoisine dye and its copper complex indicated that both of them had anticancer effects on HT-29 (colon cancer) cell line and they may be new candidates for treatment of the colon cancer. PMID:27152751

  19. Percutaneous Dorsal Instrumentation of Vertebral Burst Fractures: Value of Additional Percutaneous Intravertebral Reposition—Cadaver Study

    PubMed Central

    Krüger, Antonio; Schmuck, Maya; Noriega, David C.; Ruchholtz, Steffen; Baroud, Gamal; Oberkircher, Ludwig

    2015-01-01

    Purpose. The treatment of vertebral burst fractures is still controversial. The aim of the study is to evaluate the purpose of additional percutaneous intravertebral reduction when combined with dorsal instrumentation. Methods. In this biomechanical cadaver study twenty-eight spine segments (T11-L3) were used (male donors, mean age 64.9 ± 6.5 years). Burst fractures of L1 were generated using a standardised protocol. After fracture all spines were allocated to four similar groups and randomised according to surgical techniques (posterior instrumentation; posterior instrumentation + intravertebral reduction device + cement augmentation; posterior instrumentation + intravertebral reduction device without cement; and intravertebral reduction device + cement augmentation). After treatment, 100000 cycles (100–600 N, 3 Hz) were applied using a servohydraulic loading frame. Results. Overall anatomical restoration was better in all groups where the intravertebral reduction device was used (p < 0.05). In particular, it was possible to restore central endplates (p > 0.05). All techniques decreased narrowing of the spinal canal. After loading, clearance could be maintained in all groups fitted with the intravertebral reduction device. Narrowing increased in the group treated with dorsal instrumentation. Conclusions. For height and anatomical restoration, the combination of an intravertebral reduction device with dorsal instrumentation showed significantly better results than sole dorsal instrumentation. PMID:26137481

  20. Experimental study of enhanced heat transfer by addition of CuO nanoparticle

    NASA Astrophysics Data System (ADS)

    Jesumathy, Stella; Udayakumar, M.; Suresh, S.

    2012-06-01

    An energy storage system has been designed to study the thermal characteristics of paraffin wax with an embedded nano size copper oxide (CuO) particle. This paper presents studies conducted on phase transition times, heat fraction as well as heat transfer characteristics of paraffin wax as phase change material (PCM) embedded with CuO nanoparticles. 40 nm mean size CuO particles of 2, 5 and 10% by weight were dispersed in PCM for this study. Experiments were performed on a heat exchanger with 1.5-10 l/min of heat transfer fluid (HTF) flow. Time-based variations of the temperature distributions are revealed from the results of observations of melting and solidification curves. The results strongly suggested that the thermal conductivity enhances 6, 6.7 and 7.8% in liquid state and in dynamic viscosity it enhances by 5, 14 and 30% with increasing mass fraction of the CNEPs. The thermal conductivity ratio of the composites can be augmented by a factor up to 1.3. The heat transfer coefficient during solidification increased about 78% for the maximum flow rate. The analysis of experimental results reveals that the addition of copper oxide nanoparticles to the paraffin wax enhances both the conduction and natural convection very effectively in composites and in paraffin wax. The paraffin wax-based composites have great potential for energy storage applications like industrial waste heat recovery, solar thermal applications and solar based dynamic space power generation with optimal fraction of copper oxide nanoparticles.

  1. Increased Risk of Additional Cancers Among Patients with Gastrointestinal Stromal Tumors: A Population-Based Study

    PubMed Central

    Murphy, James D.; Ma, Grace L.; Baumgartner, Joel M.; Madlensky, Lisa; Burgoyne, Adam M.; Tang, Chih-Min; Martinez, Maria Elena; Sicklick, Jason K.

    2015-01-01

    Purpose Most gastrointestinal stromal tumors (GIST) are considered non-hereditary or sporadic. However, single-institution studies suggest that GIST patients develop additional malignancies with increased frequencies. We hypothesized that we could gain greater insight into possible associations between GIST and other malignancies using a national cancer database inquiry. Methods Patients diagnosed with GIST (2001–2011) in the Surveillance, Epidemiology, and End Results database were included. Standardized prevalence ratios (SPRs) and standardized incidence ratios (SIRs) were used to quantify cancer risks incurred by GIST patients before and after GIST diagnoses, respectively, when compared with the general U.S. population. Results Of 6,112 GIST patients, 1,047 (17.1%) had additional cancers. There were significant increases in overall cancer rates: 44% (SPR=1.44) before diagnosis and 66% (SIR=1.66) after GIST diagnoses. Malignancies with significantly increased occurrence both before/after diagnoses included other sarcomas (SPR=5.24/SIR=4.02), neuroendocrine-carcinoid tumors (SPR=3.56/SIR=4.79), non-Hodgkin’s lymphoma (SPR=1.69/SIR=1.76), and colorectal adenocarcinoma (SPR=1.51/SIR=2.16). Esophageal adenocarcinoma (SPR=12.0), bladder adenocarcinoma (SPR=7.51), melanoma (SPR=1.46), and prostate adenocarcinoma (SPR=1.20) were significantly more common only before GIST. Ovarian carcinoma (SIR=8.72), small intestine adenocarcinoma (SIR=5.89), papillary thyroid cancer (SIR=5.16), renal cell carcinoma (SIR=4.46), hepatobiliary adenocarcinomas (SIR=3.10), gastric adenocarcinoma (SIR=2.70), pancreatic adenocarcinoma (SIR=2.03), uterine adenocarcinoma (SIR=1.96), non-small cell lung cancer (SIR=1.74), and transitional cell carcinoma of the bladder (SIR=1.65) were significantly more common only after GIST. Conclusion This is the first population-based study to characterize the associations and temporal relationships between GIST and other cancers, both by site and

  2. Fundamental "Uncertainty" in Science

    NASA Astrophysics Data System (ADS)

    Reichl, Linda E.

    The conference on "Uncertainty and Surprise" was concerned with our fundamental inability to predict future events. How can we restructure organizations to effectively function in an uncertain environment? One concern is that many large complex organizations are built on mechanical models, but mechanical models cannot always respond well to "surprises." An underlying assumption a bout mechanical models is that, if we give them enough information about the world, they will know the future accurately enough that there will be few or no surprises. The assumption is that the future is basically predictable and deterministic.

  3. Fundamental experiments in velocimetry

    SciTech Connect

    Briggs, Matthew Ellsworth; Hull, Larry; Shinas, Michael

    2009-01-01

    One can understand what velocimetry does and does not measure by understanding a few fundamental experiments. Photon Doppler Velocimetry (PDV) is an interferometer that will produce fringe shifts when the length of one of the legs changes, so we might expect the fringes to change whenever the distance from the probe to the target changes. However, by making PDV measurements of tilted moving surfaces, we have shown that fringe shifts from diffuse surfaces are actually measured only from the changes caused by the component of velocity along the beam. This is an important simplification in the interpretation of PDV results, arising because surface roughness randomizes the scattered phases.

  4. 78 FR 68461 - Guidance for Industry: Studies To Evaluate the Utility of Anti-Salmonella Chemical Food Additives...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-11-14

    ... Anti- Salmonella Chemical Food Additives in Feeds; Request for Comments AGENCY: Food and Drug... Chemical Food Additives in Feeds,'' and is seeking comments on this guidance before revisions are made... Guidance for Industry: Studies to Evaluate the Utility of Anti-Salmonella Chemical Food Additives in...

  5. Beyond the Call of Duty: A Qualitative Study of Teachers' Additional Responsibilities Related to Sexuality Education

    ERIC Educational Resources Information Center

    Eisenberg, Marla E.; Madsen, Nikki; Oliphant, Jennifer A.; Resnick, Michael

    2011-01-01

    Seven focus groups were conducted with sexuality educators in Minnesota to explore ways that teaching sexuality education differs from teaching other health education content and to determine if additional supports or resources are needed for sexuality educators. Teachers described many specific additional responsibilities or concerns related to…

  6. Addition reaction of alkyl radical to C60 fullerene: Density functional theory study

    NASA Astrophysics Data System (ADS)

    Tachikawa, Hiroto; Kawabata, Hiroshi

    2016-02-01

    Functionalized fullerenes are known as a high-performance molecules. In this study, the alkyl-functionalized fullerenes (denoted by R-C60) have been investigated by means of the density functional theory (DFT) method to elucidate the effects of functionalization on the electronic states of fullerene. Also, the reaction mechanism of alkyl radicals with C60 was investigated. The methyl, ethyl, propyl, and butyl radicals (denoted by n = 1-4, where n means the number of carbon atoms in the alkyl radical) were examined as alkyl radicals. The DFT calculation showed that the alkyl radical binds to the carbon atom of C60 at the on-top site, and a strong C-C single bond is formed. The binding energies of alkyl radicals to C60 were distributed in the range of 31.8-35.1 kcal mol-1 at the CAM-B3LYP/6-311G(d,p) level. It was found that the activation barrier exists before alkyl addition, the barrier heights were calculated to be 2.1-2.8 kcal mol-1. The electronic states of R-C60 complexes were discussed on the basis of the theoretical results.

  7. Experimental study of combustion characteristics of nanoscale metal and metal oxide additives in biofuel (ethanol).

    PubMed

    Jones, Matthew; Li, Calvin H; Afjeh, Abdollah; Peterson, Gp

    2011-01-01

    An experimental investigation of the combustion behavior of nano-aluminum (n-Al) and nano-aluminum oxide (n-Al2O3) particles stably suspended in biofuel (ethanol) as a secondary energy carrier was conducted. The heat of combustion (HoC) was studied using a modified static bomb calorimeter system. Combustion element composition and surface morphology were evaluated using a SEM/EDS system. N-Al and n-Al2O3 particles of 50- and 36-nm diameters, respectively, were utilized in this investigation. Combustion experiments were performed with volume fractions of 1, 3, 5, 7, and 10% for n-Al, and 0.5, 1, 3, and 5% for n-Al2O3. The results indicate that the amount of heat released from ethanol combustion increases almost linearly with n-Al concentration. N-Al volume fractions of 1 and 3% did not show enhancement in the average volumetric HoC, but higher volume fractions of 5, 7, and 10% increased the volumetric HoC by 5.82, 8.65, and 15.31%, respectively. N-Al2O3 and heavily passivated n-Al additives did not participate in combustion reactively, and there was no contribution from Al2O3 to the HoC in the tests. A combustion model that utilized Chemical Equilibrium with Applications was conducted as well and was shown to be in good agreement with the experimental results. PMID:21711760

  8. Experimental study of combustion characteristics of nanoscale metal and metal oxide additives in biofuel (ethanol)

    NASA Astrophysics Data System (ADS)

    Jones, Matthew; Li, Calvin H.; Afjeh, Abdollah; Peterson, Gp

    2011-12-01

    An experimental investigation of the combustion behavior of nano-aluminum (n-Al) and nano-aluminum oxide (n-Al2O3) particles stably suspended in biofuel (ethanol) as a secondary energy carrier was conducted. The heat of combustion (HoC) was studied using a modified static bomb calorimeter system. Combustion element composition and surface morphology were evaluated using a SEM/EDS system. N-Al and n-Al2O3 particles of 50- and 36-nm diameters, respectively, were utilized in this investigation. Combustion experiments were performed with volume fractions of 1, 3, 5, 7, and 10% for n-Al, and 0.5, 1, 3, and 5% for n-Al2O3. The results indicate that the amount of heat released from ethanol combustion increases almost linearly with n-Al concentration. N-Al volume fractions of 1 and 3% did not show enhancement in the average volumetric HoC, but higher volume fractions of 5, 7, and 10% increased the volumetric HoC by 5.82, 8.65, and 15.31%, respectively. N-Al2O3 and heavily passivated n-Al additives did not participate in combustion reactively, and there was no contribution from Al2O3 to the HoC in the tests. A combustion model that utilized Chemical Equilibrium with Applications was conducted as well and was shown to be in good agreement with the experimental results.

  9. Experimental study of combustion characteristics of nanoscale metal and metal oxide additives in biofuel (ethanol)

    PubMed Central

    2011-01-01

    An experimental investigation of the combustion behavior of nano-aluminum (n-Al) and nano-aluminum oxide (n-Al2O3) particles stably suspended in biofuel (ethanol) as a secondary energy carrier was conducted. The heat of combustion (HoC) was studied using a modified static bomb calorimeter system. Combustion element composition and surface morphology were evaluated using a SEM/EDS system. N-Al and n-Al2O3 particles of 50- and 36-nm diameters, respectively, were utilized in this investigation. Combustion experiments were performed with volume fractions of 1, 3, 5, 7, and 10% for n-Al, and 0.5, 1, 3, and 5% for n-Al2O3. The results indicate that the amount of heat released from ethanol combustion increases almost linearly with n-Al concentration. N-Al volume fractions of 1 and 3% did not show enhancement in the average volumetric HoC, but higher volume fractions of 5, 7, and 10% increased the volumetric HoC by 5.82, 8.65, and 15.31%, respectively. N-Al2O3 and heavily passivated n-Al additives did not participate in combustion reactively, and there was no contribution from Al2O3 to the HoC in the tests. A combustion model that utilized Chemical Equilibrium with Applications was conducted as well and was shown to be in good agreement with the experimental results. PMID:21711760

  10. Meiofaunal and bacterial community response to diesel additions in a microcosm study.

    PubMed

    Lindgren, J Fredrik; Hassellöv, Ida-Maja; Dahllöf, Ingela

    2012-03-01

    Effects of low PAH-containing diesel were studied in a 60-day microcosm experiment at PAH concentrations 130, 1300 and 13,000μg/kg sediment. Nutrient fluxes, potential nitrification and meiofaunal community composition were analysed at three time points. Changed ∑NOx-fluxes indicated reduced sediment nitrification in Medium and High with time, in agreement with lowered potential nitrification rates in all treatments. Reduction in silicate and phosphate fluxes over time suggested severe effects on activity of meiofauna. Reduced activity increased the anoxic sediment layer, which could have contributed to the changed ∑NOx-fluxes. There were significant differences in meiofaunal community composition after 30 and 60days in Medium and High. Changes were due to increasing numbers of harpacticoids and the foraminiferan group Rotaliina, as well as decreasing numbers of Nematodes and the foraminiferan group Reophax. In spite of the low PAH-level, small additions of this diesel can still have pronounced effects on meiofaunal and bacterial communities.

  11. A theoretical study of wave dispersion and thermal conduction for HMX/additive interfaces

    NASA Astrophysics Data System (ADS)

    Long, Yao; Chen, Jun

    2014-04-01

    The wave dispersion rule for non-uniform material is useful for ultrasonic inspection and engine life prediction, and also is key in achieving an understanding of the energy dissipation and thermal conduction properties of solid material. On the basis of linear response theory and molecular dynamics, we derive a set of formulas for calculating the wave dispersion rate of interface systems, and study four kinds of interfaces inside plastic bonded explosives: HMX/{HMX, TATB, F2312, F2313}. (HMX: octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine; TATB: 1,3,5-triamino-2,4,6-trinitrobenzene; F2312, F2313: fluoropolymers). The wave dispersion rate is obtained over a wide frequency range from kHz to PHz. We find that at low frequency, the rate is proportional to the square of the frequency, and at high frequency, the rate couples with the molecular vibration modes at the interface. By using the results, the thermal conductivities of HMX/additive interfaces are derived, and a physical model is built for describing the total thermal conductivity of mixture explosives, including HMX multi-particle systems and {TATB, F2312, F2313}-coated HMX.

  12. Comparative study of trimethyl phosphite and trimethyl phosphate as electrolyte additives in lithium ion batteries

    NASA Astrophysics Data System (ADS)

    Yao, X. L.; Xie, S.; Chen, C. H.; Wang, Q. S.; Sun, J. H.; Li, Y. L.; Lu, S. X.

    Safety concerns of lithium ion batteries have been the key problems in their practical applications. Trimethyl phosphite (TMP(i)) and trimethyl phosphate (TMP(a)) were used as the electrolyte additives to improve the safety and electrochemical performance of lithium cells. Gallvanostatic cell cycling, flammability test and thermal stability measurements by means of accelerated rate calorimeter (ARC) and micro calorimeter were performed. It is found that both TMP(i) and TMP(a) reduce the flammability of the electrolyte. The TMP(i) additive not only enhances the thermal stability of the electrolyte, but also improves its electrochemical performance. The TMP(a) additive can improve the thermal stability of the electrolyte at the expense of some degree of degradation of its electrochemical performance. Therefore, TMP(i) is a better flame retardant additive in the electrolyte compared with TMP(a).

  13. Fortification of yogurts with different antioxidant preservatives: A comparative study between natural and synthetic additives.

    PubMed

    Caleja, Cristina; Barros, Lillian; Antonio, Amilcar L; Carocho, Márcio; Oliveira, M Beatriz P P; Ferreira, Isabel C F R

    2016-11-01

    Consumers demand more and more so-called "natural" products and, therefore, the aim of this work was to compare the effects of natural versus synthetic antioxidant preservatives in yogurts. Matricaria recutita L. (chamomile) and Foeniculum vulgare Mill. (fennel) decoctions were tested as natural additives, while potassium sorbate (E202) was used as a synthetic additive. The fortification of yogurts with natural and synthetic antioxidants did not cause significant changes in the yoghurt pH and nutritional value, in comparison with control samples (yogurt without any additive). However, the fortified yogurts showed higher antioxidant activity, mainly the yogurts with natural additives (and among these, the ones with chamomile decoction). Overall, it can be concluded that plant decoctions can be used to develop novel yogurts, by replacing synthetic preservatives and improving the antioxidant properties of the final product, without changing the nutritional profile. PMID:27211646

  14. Fortification of yogurts with different antioxidant preservatives: A comparative study between natural and synthetic additives.

    PubMed

    Caleja, Cristina; Barros, Lillian; Antonio, Amilcar L; Carocho, Márcio; Oliveira, M Beatriz P P; Ferreira, Isabel C F R

    2016-11-01

    Consumers demand more and more so-called "natural" products and, therefore, the aim of this work was to compare the effects of natural versus synthetic antioxidant preservatives in yogurts. Matricaria recutita L. (chamomile) and Foeniculum vulgare Mill. (fennel) decoctions were tested as natural additives, while potassium sorbate (E202) was used as a synthetic additive. The fortification of yogurts with natural and synthetic antioxidants did not cause significant changes in the yoghurt pH and nutritional value, in comparison with control samples (yogurt without any additive). However, the fortified yogurts showed higher antioxidant activity, mainly the yogurts with natural additives (and among these, the ones with chamomile decoction). Overall, it can be concluded that plant decoctions can be used to develop novel yogurts, by replacing synthetic preservatives and improving the antioxidant properties of the final product, without changing the nutritional profile.

  15. Chemostat Studies of TCE-Dehalogenating Anaerobic Consortia under Excess and Limited Electron Donor Addition

    NASA Astrophysics Data System (ADS)

    Semprini, L.; Azizian, M.; Green, J.; Mayer-Blackwell, K.; Spormann, A. M.

    2015-12-01

    Two cultures - the Victoria Strain (VS) and the Evanite Strain (EV), enriched with the organohalide respiring bacteria Dehalococcoides mccartyi - were grown in chemostats for more than 4 years at a mean cell residence time of 50 days. The slow doubling rate represents growth likely experienced in the subsurface. The chemostats were fed formate as an electron donor and trichloroethene (TCE) as the terminal electron acceptor. Under excess formate conditions, stable operation was observed with respect to TCE transformation, steady-state hydrogen (H2) concentrations (40 nM), and the structure of the dehalogenating community. Both cultures completely transformed TCE to ethene, with minor amounts of vinyl chloride (VC) observed, along with acetate formation. When formate was limited, TCE was transformed incompletely to ethene (40-60%) and VC (60- 40%), and H2 concentrations ranged from 1 to 3 nM. The acetate concentration dropped below detection. Batch kinetic studies of TCE transformation with chemostat harvested cells found transformation rates of c-DCE and VC were greatly reduced when the cells were grown with limited formate. Upon increasing formate addition to the chemostats, from limited to excess, essentially complete transformation of TCE to ethene was achieved. The increase in formate was associated with an increase in H2 concentration and the production of acetate. Results of batch kinetic tests showed increases in transformation rates for TCE and c-DCE by factors of 3.5 and 2.5, respectively, while VC rates increased by factors of 33 to 500, over a six month period. Molecular analysis of chemostat samples is being performed to quantify the changes in copy numbers of reductase genes and to determine whether shifts in the strains of Dehalococcoides mccartyi where responsible for the observed rate increases. The results demonstrate the importance of electron donor supply for successful in-situ remediation.

  16. Study of metal whiskers growth and mitigation technique using additive manufacturing

    NASA Astrophysics Data System (ADS)

    Gullapalli, Vikranth

    For years, the alloy of choice for electroplating electronic components has been tin-lead (Sn-Pb) alloy. However, the legislation established in Europe on July 1, 2006, required significant lead (Pb) content reductions from electronic hardware due to its toxic nature. A popular alternative for coating electronic components is pure tin (Sn). However, pure tin has the tendency to spontaneously grow electrically conductive Sn whisker during storage. Sn whisker is usually a pure single crystal tin with filament or hair-like structures grown directly from the electroplated surfaces. Sn whisker is highly conductive, and can cause short circuits in electronic components, which is a very significant reliability problem. The damages caused by Sn whisker growth are reported in very critical applications such as aircraft, spacecraft, satellites, and military weapons systems. They are also naturally very strong and are believed to grow from compressive stresses developed in the Sn coating during deposition or over time. The new directive, even though environmentally friendly, has placed all lead-free electronic devices at risk because of whisker growth in pure tin. Additionally, interest has occurred about studying the nature of other metal whiskers such as zinc (Zn) whiskers and comparing their behavior to that of Sn whiskers. Zn whiskers can be found in flooring of data centers which can get inside electronic systems during equipment reorganization and movement and can also cause systems failure. Even though the topic of metal whiskers as reliability failure has been around for several decades to date, there is no successful method that can eliminate their growth. This thesis will give further insights towards the nature and behavior of Sn and Zn whiskers growth, and recommend a novel manufacturing technique that has potential to mitigate metal whiskers growth and extend life of many electronic devices.

  17. A study of the electrochemistry of nickel hydroxide electrodes with various additives

    NASA Astrophysics Data System (ADS)

    Zhu, Wen-Hua; Ke, Jia-Jun; Yu, Hong-Mei; Zhang, Deng-Jun

    Nickel composite electrodes (NCE) with various additives are prepared by a chemical impregnation method from nitrate solutions on sintered porous plaques. The electrochemical properties, such as utilization of active material, swelling and the discharge potential of the nickel oxide electrode (NOE) are determined mainly through the composition of the active material and the characteristics of nickel plaques. Most additives (Mg, Ca, Sr, Ba, Zn, Cd, Co, Li and Al hydroxide) exert effects on the discharge potential and swelling of the NOE. Chemical co-precipitation with the addition of calcium, zinc, magnesium and barium hydroxide increases the discharge potential by more than 20 mV, but that with zinc hydroxide results in an obvious decrease of active-material utilization and that with calcium and magnesium hydroxide produces a larger increase of electrode thickness. The effects of anion additives are also examined. Less than 1% mol of NiS in the active material increases the discharge potential. Cadmium, cobalt and zinc hydroxide are excellent additives for preventing swelling of the NCE. Slow voltammetry (0.2 mV s -1) in 6 M KOH is applied to characterize the oxygen-evolving potential of the NCE. The difference between the oxygen-evolution potential and the potential of the oxidation peak for the NCE with additives of calcium, lithium, barium and aluminium hydroxide is at least + 60 mV.

  18. Fundamental studies in the molecular basis of laser-induced retinal damage. Annual report (Final), 1 March 1979-15 March 1985

    SciTech Connect

    Lewis, A.

    1985-04-01

    This report describes the advances made in work for the Ocular Hazards Program. Research saw seen the first application of femtosecond lasers to the visual system. IT was discovered that anions can activate visual photoreceptors in the dark. One anionic activator is the commonly used dental agent fluoride. The data on in-vitro preparations indicate that these anions modulate photoreceptor biochemistry and may effect photoreceptor sensitivity. The image of various elements in photoreceptors and adjacent tissues were identified. The spatial images should play important roles in extending our understanding of the fundamental mechanisms of laser damage. Complementary techniques have been developed to view, in light microscopy, actin filaments in photoreceptors. The staining procedures developed can be applied to study the laser-damaged retina. The protective nature of oil droplets in the turtle has been studied. Data demonstrating rapid mechanical motions in vertebrate photoreceptors was obtained. Such rapid mechanical motions, which parallel electrophysiological responses in the cell, may lie at the very basis of photoreceptor function. Laser-damage mechanisms should be reevaluated in terms of this new data. The effect of laser light on these newly discovered mechanical motions will surely lead to new and improved understandings of low-level laser ocular hazards.

  19. Fundamental studies of matrix-assisted laser desorption/ionization, using time-of-flight mass spectrometry to identify biological molecules

    SciTech Connect

    Eades, D.; Wruck, D.; Gregg, H.

    1996-11-11

    MALDI MS was developed as a way of getting molecular weight information on small quantities (picomole to femtomole levels) of high-mass, thermally labile macromolecules. While most other analytical MS ionization techniques cause fragmentation, decomposition, or multiple charging, MALDI efficiently places intact macromolecules into the gas phase with little fragmentation or rearrangement. This project had 3 objectives: establish the MALDI capability at LLNL, perform fundamental studies of analyte-matrix interactions, and apply the technique for biochemical research. A retired time-of-flight instrument was adapted for MALDI analyses, relevant parameters influencing the MALDI process were identified for further study (matrix molar absorptivity, sample crystal preparation), and collaborations were established with research groups in the Biology and Biotechnology Research Program at LLNL. In MALDI, the macromolecule of interest is mixed with a high-molar excess (1:100 to 1:10,000) of an organic matrix which readily absorbs energy at the wavelength corresponding to a UV laser. Upon laser irradiation, the matrix absorbs the majority of the energy, causing it to desorb from the surface and gently release the macromolecule into the gas phase with little or no fragmentation. Once in the gas phase, ion-molecule reactions between excited matrix and neutral macromolecules generated ionized analyte species which then can be focused into a MS for detection.

  20. Wall of fundamental constants

    SciTech Connect

    Olive, Keith A.; Peloso, Marco; Uzan, Jean-Philippe

    2011-02-15

    We consider the signatures of a domain wall produced in the spontaneous symmetry breaking involving a dilatonlike scalar field coupled to electromagnetism. Domains on either side of the wall exhibit slight differences in their respective values of the fine-structure constant, {alpha}. If such a wall is present within our Hubble volume, absorption spectra at large redshifts may or may not provide a variation in {alpha} relative to the terrestrial value, depending on our relative position with respect to the wall. This wall could resolve the contradiction between claims of a variation of {alpha} based on Keck/Hires data and of the constancy of {alpha} based on Very Large Telescope data. We derive the properties of the wall and the parameters of the underlying microscopic model required to reproduce the possible spatial variation of {alpha}. We discuss the constraints on the existence of the low-energy domain wall and describe its observational implications concerning the variation of the fundamental constants.

  1. Fundamentals in Nuclear Physics

    NASA Astrophysics Data System (ADS)

    Basdevant, Jean-Louis, Rich, James, Spiro, Michael

    This course on nuclear physics leads the reader to the exploration of the field from nuclei to astrophysical issues. Much nuclear phenomenology can be understood from simple arguments such as those based on the Pauli principle and the Coulomb barrier. This book is concerned with extrapolating from such arguments and illustrating nuclear systematics with experimental data. Starting with the basic concepts in nuclear physics, nuclear models, and reactions, the book covers nuclear decays and the fundamental electro-weak interactions, radioactivity, and nuclear energy. After the discussions of fission and fusion leading into nuclear astrophysics, there is a presentation of the latest ideas about cosmology. As a primer this course will lay the foundations for more specialized subjects. This book emerged from a series of topical courses the authors delivered at the Ecole Polytechnique and will be useful for graduate students and for scientists in a variety of fields.

  2. Fundamentals of zoological scaling

    NASA Astrophysics Data System (ADS)

    Lin, Herbert

    1982-01-01

    Most introductory physics courses emphasize highly idealized problems with unique well-defined answers. Though many textbooks complement these problems with estimation problems, few books present anything more than an elementary discussion of scaling. This paper presents some fundamentals of scaling in the zoological domain—a domain complex by any standard, but one also well suited to illustrate the power of very simple physical ideas. We consider the following animal characteristics: skeletal weight, speed of running, height and range of jumping, food consumption, heart rate, lifetime, locomotive efficiency, frequency of wing flapping, and maximum sizes of animals that fly and hover. These relationships are compared to zoological data and everyday experience, and match reasonably well.

  3. Maltreated children's representations of mother and an additional caregiver: a longitudinal study.

    PubMed

    Manashko, Shany; Besser, Avi; Priel, Beatriz

    2009-04-01

    In the current longitudinal investigation, we explored the continuity of and changes in the mental representations of the mother and an additional caregiver among forty-five 9- to 11-year-old children who had been severely maltreated and subsequently placed in long-term residential care as well as the relationships between the content and structure of these representations and teacher's assessments of the child's externalizing and internalizing symptoms. At Time 1, a nonmaltreated comparison group was assessed concomitantly. Compared to nonmaltreated children, maltreated children scored higher for externalizing and internalizing symptoms, and their maternal representations were found to be significantly less benevolent and integrated and more punitive. In addition, among the maltreated children, the additional caregiver representations were found to be more benevolent and integrated, and less punitive, than the maternal representations. After 30 months, the maltreated children's levels of externalizing and internalizing symptoms diminished, their maternal representations become more benevolent and less punitive, and the additional caregiver representations became less benevolent. Moreover, the Benevolence of the additional caregiver representation was found to predict these children's changes in externalizing symptoms beyond the effects of their symptomatology and its associations with the Benevolence of these representations at Time 1. PMID:19220720

  4. Fundamental issues in questionnaire design.

    PubMed

    Murray, P

    1999-07-01

    The questionnaire is probably the most common form of data collection tool used in nursing research. There is a misconception that anyone with a clear grasp of English and a modicum of common sense can design an effective questionnaire. Contrary to such common belief, this article will demonstrate that questionnaire design is a complex and time consuming process, but a necessary labour to ensure valid and reliable data is collected. In addition, meticulous construction is more likely to yield data that can be utilized in the pursuit of objective, quantitative and generalizable truths, upon which practice and policy decisions can be formulated. This article examines a myriad of fundamental issues surrounding questionnaire design, which encompass question wording, question order, presentation, administration and data collection, amongst other issues.

  5. Computational study of the rate constants and free energies of intramolecular radical addition to substituted anilines.

    PubMed

    Gansäuer, Andreas; Seddiqzai, Meriam; Dahmen, Tobias; Sure, Rebecca; Grimme, Stefan

    2013-01-01

    The intramolecular radical addition to aniline derivatives was investigated by DFT calculations. The computational methods were benchmarked by comparing the calculated values of the rate constant for the 5-exo cyclization of the hexenyl radical with the experimental values. The dispersion-corrected PW6B95-D3 functional provided very good results with deviations for the free activation barrier compared to the experimental values of only about 0.5 kcal mol(-1) and was therefore employed in further calculations. Corrections for intramolecular London dispersion and solvation effects in the quantum chemical treatment are essential to obtain consistent and accurate theoretical data. For the investigated radical addition reaction it turned out that the polarity of the molecules is important and that a combination of electrophilic radicals with preferably nucleophilic arenes results in the highest rate constants. This is opposite to the Minisci reaction where the radical acts as nucleophile and the arene as electrophile. The substitution at the N-atom of the aniline is crucial. Methyl substitution leads to slower addition than phenyl substitution. Carbamates as substituents are suitable only when the radical center is not too electrophilic. No correlations between free reaction barriers and energies (ΔG (‡) and ΔG R) are found. Addition reactions leading to indanes or dihydrobenzofurans are too slow to be useful synthetically.

  6. Effect of stabilizing additives on the structure and hydration of proteins: a study involving monoclinic lysozyme.

    PubMed

    Saraswathi, N T; Sankaranarayanan, R; Vijayan, M

    2002-07-01

    In pursuance of a long-range programme on the hydration, mobility and action of proteins, the structural basis of the stabilizing effect of sugars and polyols is being investigated. With two crystallographically independent molecules with slightly different packing environments in the crystal, monoclinic lysozyme constitutes an ideal system for exploring the problem. The differences in the structure and hydration of the two molecules provide a framework for examining the changes caused by stabilizing additives. Monoclinic crystals were grown under native conditions and also in the presence of 10% sucrose, 15% trehalose, 10% trehalose, 10% sorbitol and 5% glycerol. The crystal structures were refined at resolutions ranging from 1.8 to 2.1 A. The average B values, and hence the mobility of the structure, are lower in the presence of additives than in the native crystals. However, a comparison of the structures indicates that the effect of the additives on the structure and the hydration shell around the protein molecule is considerably less than that caused by differences in packing. It is also less than that caused by the replacement of NaNO(3) by NaCl as the precipitant in the crystallization experiments. This result is not in conformity with the commonly held belief that additives exert their stabilizing effect through the reorganization of the hydration shell, at least as far as the ordered water molecules are concerned.

  7. Studies on the Food Additive Propyl Gallate: Synthesis, Structural Characterization, and Evaluation of the Antioxidant Activity

    ERIC Educational Resources Information Center

    Garrido, Jorge; Garrido, E. Manuela; Borges, Fernanda

    2012-01-01

    Antioxidants are additives largely used in industry for delaying, retarding, or preventing the development of oxidative deterioration. Propyl gallate (E310) is a phenolic antioxidant extensively used in the food, cosmetics, and pharmaceutical industries. A series of lab experiments have been developed to teach students about the importance and…

  8. Computational study of the rate constants and free energies of intramolecular radical addition to substituted anilines.

    PubMed

    Gansäuer, Andreas; Seddiqzai, Meriam; Dahmen, Tobias; Sure, Rebecca; Grimme, Stefan

    2013-01-01

    The intramolecular radical addition to aniline derivatives was investigated by DFT calculations. The computational methods were benchmarked by comparing the calculated values of the rate constant for the 5-exo cyclization of the hexenyl radical with the experimental values. The dispersion-corrected PW6B95-D3 functional provided very good results with deviations for the free activation barrier compared to the experimental values of only about 0.5 kcal mol(-1) and was therefore employed in further calculations. Corrections for intramolecular London dispersion and solvation effects in the quantum chemical treatment are essential to obtain consistent and accurate theoretical data. For the investigated radical addition reaction it turned out that the polarity of the molecules is important and that a combination of electrophilic radicals with preferably nucleophilic arenes results in the highest rate constants. This is opposite to the Minisci reaction where the radical acts as nucleophile and the arene as electrophile. The substitution at the N-atom of the aniline is crucial. Methyl substitution leads to slower addition than phenyl substitution. Carbamates as substituents are suitable only when the radical center is not too electrophilic. No correlations between free reaction barriers and energies (ΔG (‡) and ΔG R) are found. Addition reactions leading to indanes or dihydrobenzofurans are too slow to be useful synthetically. PMID:24062821

  9. Vector generalized additive models for extreme rainfall data analysis (study case rainfall data in Indramayu)

    NASA Astrophysics Data System (ADS)

    Utami, Eka Putri Nur; Wigena, Aji Hamim; Djuraidah, Anik

    2016-02-01

    Rainfall pattern are good indicators for potential disasters. Global Circulation Model (GCM) contains global scale information that can be used to predict the rainfall data. Statistical downscaling (SD) utilizes the global scale information to make inferences in the local scale. Essentially, SD can be used to predict local scale variables based on global scale variables. SD requires a method to accommodate non linear effects and extreme values. Extreme value Theory (EVT) can be used to analyze the extreme value. One of methods to identify the extreme events is peak over threshold that follows Generalized Pareto Distribution (GPD). The vector generalized additive model (VGAM) is an extension of the generalized additive model. It is able to accommodate linear or nonlinear effects by involving more than one additive predictors. The advantage of VGAM is to handle multi response models. The key idea of VGAM are iteratively reweighted least square for maximum likelihood estimation, penalized smoothing, fisher scoring and additive models. This works aims to analyze extreme rainfall data in Indramayu using VGAM. The results show that the VGAM with GPD is able to predict extreme rainfall data accurately. The prediction in February is very close to the actual value at quantile 75.

  10. Teaching Young Children Decomposition Strategies to Solve Addition Problems: An Experimental Study

    ERIC Educational Resources Information Center

    Cheng, Zi-Juan

    2012-01-01

    The ability to count has traditionally been considered an important milestone in children's development of number sense. However, using counting (e.g., counting on, counting all) strategies to solve addition problems is not the best way for children to achieve their full mathematical potential and to prepare them to develop more complex and…

  11. Study on automatic optical element addition or deletion in lens optimization

    NASA Astrophysics Data System (ADS)

    Cheng, Xuemin; Wang, Yongtian; Hao, Qun

    2002-09-01

    Two lens form parameters, quantifying the symmetry of the optical system and the optical power distribution among the individual lens elements, are used as the criteria for automatic element addition or deletion in lens optimization. The scheme based on the criteria is described in this paper. Design examples are provided, which demonstrate that the scheme is practicable.

  12. Computational study of the rate constants and free energies of intramolecular radical addition to substituted anilines

    PubMed Central

    Seddiqzai, Meriam; Dahmen, Tobias; Sure, Rebecca

    2013-01-01

    Summary The intramolecular radical addition to aniline derivatives was investigated by DFT calculations. The computational methods were benchmarked by comparing the calculated values of the rate constant for the 5-exo cyclization of the hexenyl radical with the experimental values. The dispersion-corrected PW6B95-D3 functional provided very good results with deviations for the free activation barrier compared to the experimental values of only about 0.5 kcal mol−1 and was therefore employed in further calculations. Corrections for intramolecular London dispersion and solvation effects in the quantum chemical treatment are essential to obtain consistent and accurate theoretical data. For the investigated radical addition reaction it turned out that the polarity of the molecules is important and that a combination of electrophilic radicals with preferably nucleophilic arenes results in the highest rate constants. This is opposite to the Minisci reaction where the radical acts as nucleophile and the arene as electrophile. The substitution at the N-atom of the aniline is crucial. Methyl substitution leads to slower addition than phenyl substitution. Carbamates as substituents are suitable only when the radical center is not too electrophilic. No correlations between free reaction barriers and energies (ΔG ‡ and ΔG R) are found. Addition reactions leading to indanes or dihydrobenzofurans are too slow to be useful synthetically. PMID:24062821

  13. Overlay accuracy fundamentals

    NASA Astrophysics Data System (ADS)

    Kandel, Daniel; Levinski, Vladimir; Sapiens, Noam; Cohen, Guy; Amit, Eran; Klein, Dana; Vakshtein, Irina

    2012-03-01

    Currently, the performance of overlay metrology is evaluated mainly based on random error contributions such as precision and TIS variability. With the expected shrinkage of the overlay metrology budget to < 0.5nm, it becomes crucial to include also systematic error contributions which affect the accuracy of the metrology. Here we discuss fundamental aspects of overlay accuracy and a methodology to improve accuracy significantly. We identify overlay mark imperfections and their interaction with the metrology technology, as the main source of overlay inaccuracy. The most important type of mark imperfection is mark asymmetry. Overlay mark asymmetry leads to a geometrical ambiguity in the definition of overlay, which can be ~1nm or less. It is shown theoretically and in simulations that the metrology may enhance the effect of overlay mark asymmetry significantly and lead to metrology inaccuracy ~10nm, much larger than the geometrical ambiguity. The analysis is carried out for two different overlay metrology technologies: Imaging overlay and DBO (1st order diffraction based overlay). It is demonstrated that the sensitivity of DBO to overlay mark asymmetry is larger than the sensitivity of imaging overlay. Finally, we show that a recently developed measurement quality metric serves as a valuable tool for improving overlay metrology accuracy. Simulation results demonstrate that the accuracy of imaging overlay can be improved significantly by recipe setup optimized using the quality metric. We conclude that imaging overlay metrology, complemented by appropriate use of measurement quality metric, results in optimal overlay accuracy.

  14. Fundamentals of Atmospheric Radiation

    NASA Astrophysics Data System (ADS)

    Bohren, Craig F.; Clothiaux, Eugene E.

    2006-02-01

    This textbook fills a gap in the literature for teaching material suitable for students of atmospheric science and courses on atmospheric radiation. It covers the fundamentals of emission, absorption, and scattering of electromagnetic radiation from ultraviolet to infrared and beyond. Much of the book applies to planetary atmosphere. The authors are physicists and teach at the largest meteorology department of the US at Penn State. Craig T. Bohren has taught the atmospheric radiation course there for the past 20 years with no book. Eugene Clothiaux has taken over and added to the course notes. Problems given in the text come from students, colleagues, and correspondents. The design of the figures especially for this book is meant to ease comprehension. Discussions have a graded approach with a thorough treatment of subjects, such as single scattering by particles, at different levels of complexity. The discussion of the multiple scattering theory begins with piles of plates. This simple theory introduces concepts in more advanced theories, i.e. optical thickness, single-scattering albedo, asymmetry parameter. The more complicated theory, the two-stream theory, then takes the reader beyond the pile-of-plates theory. Ideal for advanced undergraduate and graduate students of atmospheric science.

  15. A laboratory study of the perceived benefit of additional noise attenuation by houses

    NASA Technical Reports Server (NTRS)

    Flindell, I. H.

    1983-01-01

    Two Experiments were conducted to investigate the perceived benefit of additional house attenuation against aircraft flyover noise. First, subjects made annoyance judgments in a simulated living room while an operative window with real and dummy storm windows was manipulated in full view of those subjects. Second, subjects made annoyance judgments in an anechoic audiometric test chamber of frequency shaped noise signals having spectra closely matched to those of the aircraft flyover noises reproduced in the first experiment. These stimuli represented the aircraft flyover noises in levels and spectra but without the situational and visual cues present in the simulated living room. Perceptual constancy theory implies that annoyance tends to remain constant despite reductions in noise level caused by additional attenuation of which the subjects are fully aware. This theory was supported when account was taken for a reported annoyance overestimation for certain spectra and for a simulated condition cue overreaction.

  16. A laboratory study of the perceived benefit of additional noise attenuation by houses

    NASA Astrophysics Data System (ADS)

    Flindell, I. H.

    1983-06-01

    Two Experiments were conducted to investigate the perceived benefit of additional house attenuation against aircraft flyover noise. First, subjects made annoyance judgments in a simulated living room while an operative window with real and dummy storm windows was manipulated in full view of those subjects. Second, subjects made annoyance judgments in an anechoic audiometric test chamber of frequency shaped noise signals having spectra closely matched to those of the aircraft flyover noises reproduced in the first experiment. These stimuli represented the aircraft flyover noises in levels and spectra but without the situational and visual cues present in the simulated living room. Perceptual constancy theory implies that annoyance tends to remain constant despite reductions in noise level caused by additional attenuation of which the subjects are fully aware. This theory was supported when account was taken for a reported annoyance overestimation for certain spectra and for a simulated condition cue overreaction.

  17. Thiopeptin, a New Feed-Additive Antibiotic: Biological Studies and Field Trials

    PubMed Central

    Mine, K.; Miyairi, N.; Takano, N.; Mori, S.; Watanabe, N.

    1972-01-01

    Thiopeptin is a new antibiotic, produced by Streptomyces tateyamensis and developed solely for animal use as a feed additive. The antibiotic content in animal tissue and feed was assayed in terms of the antimicrobial activity against Mycoplasma laidlawii A. This antibiotic was found to be relatively nontoxic in rats and mice. In chickens, this antibiotic is excreted into feces within 48 hr of administration and is not absorbed in tissue. It is well tolerated in both broilers and swine and is highly stable in animal feed. Thiopeptin-supplemented feed contributes to the improvement of weight gain, feed efficiency in chickens and swine, and the egg performance in layers. Thus, thiopeptin, when used as a feed additive, is quite suitable for supplementing animal nutrition. PMID:4680812

  18. Structural changes in gluten protein structure after addition of emulsifier. A Raman spectroscopy study

    NASA Astrophysics Data System (ADS)

    Ferrer, Evelina G.; Gómez, Analía V.; Añón, María C.; Puppo, María C.

    2011-06-01

    Food protein product, gluten protein, was chemically modified by varying levels of sodium stearoyl lactylate (SSL); and the extent of modifications (secondary and tertiary structures) of this protein was analyzed by using Raman spectroscopy. Analysis of the Amide I band showed an increase in its intensity mainly after the addition of the 0.25% of SSL to wheat flour to produced modified gluten protein, pointing the formation of a more ordered structure. Side chain vibrations also confirmed the observed changes.

  19. Magnetic Force Microscopy Study of Zr2Co11 -Based Nanocrystalline Materials: Effect of Mo Addition

    DOE PAGES

    Yue, Lanping; Jin, Yunlong; Zhang, Wenyong; Sellmyer, David J.

    2015-01-01

    Tmore » he addition of Molybdenum was used to modify the nanostructure and enhance coercivity of rare-earth-free Zr2Co11-based nanocrystalline permanent magnets. he effect of Mo addition on magnetic domain structures of melt spun nanocrystalline Zr16Co84-xMox(x=0, 0.5, 1, 1.5, and 2.0) ribbons has been investigated. It was found that magnetic properties and local domain structures are strongly influenced by Mo doping. he coercivity of the samples increases with the increase in Mo content (x≤1.5). he maximum energy product(BH)maxincreases with increasingxfrom 0.5 MGOe forx=0to a maximum value of 4.2 MGOe forx=1.5. he smallest domain size with a relatively short magnetic correlation length of 128 nm and largest root-mean-square phase shiftΦrmsvalue of 0.66° are observed for thex=1.5. he optimal Mo addition promotes magnetic domain structure refinement and thus leads to a significant increase in coercivity and energy product in this sample.« less

  20. Fundamental differences in axial and appendicular bone density in stress fractured and uninjured Royal Marine recruits--a matched case-control study.

    PubMed

    Davey, Trish; Lanham-New, Susan A; Shaw, Anneliese M; Cobley, Rosalyn; Allsopp, Adrian J; Hajjawi, Mark O R; Arnett, Timothy R; Taylor, Pat; Cooper, Cyrus; Fallowfield, Joanne L

    2015-04-01

    Stress fracture is a common overuse injury within military training, resulting in significant economic losses to the military worldwide. Studies to date have failed to fully identify the bone density and bone structural differences between stress fractured personnel and controls due to inadequate adjustment for key confounding factors; namely age, body size and physical fitness; and poor sample size. The aim of this study was to investigate bone differences between male Royal Marine recruits who suffered a stress fracture during the 32 weeks of training and uninjured control recruits, matched for age, body weight, height and aerobic fitness. A total of 1090 recruits were followed through training and 78 recruits suffered at least one stress fracture. Bone mineral density (BMD) was measured at the lumbar spine (LS), femoral neck (FN) and whole body (WB) using Dual X-ray Absorptiometry in 62 matched pairs; tibial bone parameters were measured using peripheral Quantitative Computer Tomography in 51 matched pairs. Serum C-terminal peptide concentration was measured as a marker of bone resorption at baseline, week-15 and week-32. ANCOVA was used to determine differences between stress fractured recruits and controls. BMD at the LS, WB and FN sites was consistently lower in the stress fracture group (P<0.001). Structural differences between the stress fracture recruits and controls were evident in all slices of the tibia, with the most prominent differences seen at the 38% tibial slice. There was a negative correlation between the bone cross-sectional area and BMD at the 38% tibial slice. There was no difference in serum CTx concentration between stress fracture recruits and matched controls at any stage of training. These results show evidence of fundamental differences in bone mass and structure in stress fracture recruits, and provide useful data on bone risk factor profiles for stress fracture within a healthy military population.

  1. Fundamental studies of defect generation in amorphous silicon alloys grown by remote plasma-enhanced chemical-vapor deposition. Final subcontract report, 1 July 1989--31 December 1992

    SciTech Connect

    Lucovsky, G.

    1993-08-01

    This report describes research to reduce the intrinsic bonding defects in amorphous and microcrystalline Si alloys by controlling the bonding chemistry and the microstructure via the deposition process reactions. The specific approach was to use remote plasma-enhanced, chemical-vapor deposition (PECVD) and reactive magnetron sputtering to limit the multiplicity of deposition inaction pathways, and thereby gain increased control over the thin-film chemistry and microstrucre. The research included (1) the deposition of amorphous and microcrystalline Si alloy materials by the PECVD process and by reactive magnetron sputtering, and (2) the evaluation of the material properties of these films for potential applications in PV devices. The focus of the research was on pining a fundamental understanding of the relationships between deposition reaction pathways, the bonding of dopant and alloy atoms, and the electrical provides of importance for PV applications. This involved studying the factors that contribute to defect generation and to defect removal and/or neutralization. In addition to the experimental studies, the research also included theoretical and modeling studies aimed at understanding the relationships between local atomic arrangements of Si and alloy atoms, and the electrical, optical, vibrational, and defect properties.

  2. Parameters and pitfalls to consider in the conduct of food additive research, Carrageenan as a case study.

    PubMed

    Weiner, Myra L

    2016-01-01

    This paper provides guidance on the conduct of new in vivo and in vitro studies on high molecular weight food additives, with carrageenan, the widely used food additive, as a case study. It is important to understand the physical/chemical properties and to verify the identity/purity, molecular weight and homogeneity/stability of the additive in the vehicle for oral delivery. The strong binding of CGN to protein in rodent chow or infant formula results in no gastrointestinal tract exposure to free CGN. It is recommended that doses of high Mw non-caloric, non-nutritive additives not exceed 5% by weight of total solid diet to avoid potential nutritional effects. Addition of some high Mw additives at high concentrations to liquid nutritional supplements increases viscosity and may affect palatability, caloric intake and body weight gain. In in vitro studies, the use of well-characterized, relevant cell types and the appropriate composition of the culture media are necessary for proper conduct and interpretation. CGN is bound to media protein and not freely accessible to cells in vitro. Interpretation of new studies on food additives should consider the interaction of food additives with the vehicle components and the appropriateness of the animal or cell model and dose-response.

  3. Parameters and pitfalls to consider in the conduct of food additive research, Carrageenan as a case study.

    PubMed

    Weiner, Myra L

    2016-01-01

    This paper provides guidance on the conduct of new in vivo and in vitro studies on high molecular weight food additives, with carrageenan, the widely used food additive, as a case study. It is important to understand the physical/chemical properties and to verify the identity/purity, molecular weight and homogeneity/stability of the additive in the vehicle for oral delivery. The strong binding of CGN to protein in rodent chow or infant formula results in no gastrointestinal tract exposure to free CGN. It is recommended that doses of high Mw non-caloric, non-nutritive additives not exceed 5% by weight of total solid diet to avoid potential nutritional effects. Addition of some high Mw additives at high concentrations to liquid nutritional supplements increases viscosity and may affect palatability, caloric intake and body weight gain. In in vitro studies, the use of well-characterized, relevant cell types and the appropriate composition of the culture media are necessary for proper conduct and interpretation. CGN is bound to media protein and not freely accessible to cells in vitro. Interpretation of new studies on food additives should consider the interaction of food additives with the vehicle components and the appropriateness of the animal or cell model and dose-response. PMID:26615870

  4. Strategic Petroleum Reserve (SPR) additional geologic site characterization studies, Bryan Mound Salt Dome, Texas

    SciTech Connect

    Neal, J.T.; Magorian, T.R.; Ahmad, S.

    1994-11-01

    This report revises the original report that was published in 1980. Some of the topics covered in the earlier report were provisional and it is now practicable to reexamine them using new or revised geotechnical data and that obtained from SPR cavern operations, which involves 16 new caverns. Revised structure maps and sections show interpretative differences as compared with the 1980 report and more definition in the dome shape and caprock structural contours, especially a major southeast-northwest trending anomalous zone. The original interpretation was of westward tilt of the dome, this revision shows a tilt to the southeast, consistent with other gravity and seismic data. This interpretation refines the evaluation of additional cavern space, by adding more salt buffer and allowing several more caverns. Additional storage space is constrained on this nearly full dome because of low-lying peripheral wetlands, but 60 MMBBL or more of additional volume could be gained in six or more new caverns. Subsidence values at Bryan Mound are among the lowest in the SPR system, averaging about 11 mm/yr (0.4 in/yr), but measurement and interpretation issues persist, as observed values are about the same as survey measurement accuracy. Periodic flooding is a continuing threat because of the coastal proximity and because peripheral portions of the site are at elevations less than 15 ft. This threat may increase slightly as future subsidence lowers the surface, but the amount is apt to be small. Caprock integrity may be affected by structural features, especially the faulting associated with anomalous zones. Injection wells have not been used extensively at Bryan Mound, but could be a practicable solution to future brine disposal needs. Environmental issues center on the areas of low elevation that are below 15 feet above mean sea level: the coastal proximity and lowland environment combined with the potential for flooding create conditions that require continuing surveillance.

  5. A near-infrared spectroscopic study of young field ultracool dwarfs: additional analysis

    NASA Astrophysics Data System (ADS)

    Allers, K. N.; Liu, M. C.

    We present additional analysis of the classification system presented in \\citet{allers13}. We refer the reader to \\citet{allers13} for a detailed discussion of our near-IR spectral type and gravity classification system. Here, we address questions and comments from participants of the Brown Dwarfs Come of Age meeting. In particular, we examine the effects of binarity and metallicity on our classification system. We also present our classification of Pleiades brown dwarfs using published spectra. Lastly, we determine SpTs and calculate gravity-sensitive indices for the BT-Settl atmospheric models and compare them to observations.

  6. The influence of bioaugmentation and biosurfactant addition on bioremediation efficiency of diesel-oil contaminated soil: feasibility during field studies.

    PubMed

    Szulc, Alicja; Ambrożewicz, Damian; Sydow, Mateusz; Ławniczak, Łukasz; Piotrowska-Cyplik, Agnieszka; Marecik, Roman; Chrzanowski, Łukasz

    2014-01-01

    The study focused on assessing the influence of bioaugmentation and addition of rhamnolipids on diesel oil biodegradation efficiency during field studies. Initial laboratory studies (measurement of emitted CO2 and dehydrogenase activity) were carried out in order to select the consortium for bioaugmentation as well as to evaluate the most appropriate concentration of rhamnolipids. The selected consortium consisted of following bacterial taxa: Aeromonas hydrophila, Alcaligenes xylosoxidans, Gordonia sp., Pseudomonas fluorescens, Pseudomonas putida, Rhodococcus equi, Stenotrophomonas maltophilia, Xanthomonas sp. It was established that the application of rhamnolipids at 150 mg/kg of soil was most appropriate in terms of dehydrogenase activity. Based on the obtained results, four treatment methods were designed and tested during 365 days of field studies: I) natural attenuation; II) addition of rhamnolipids; III) bioaugmentation; IV) bioaugmentation and addition of rhamnolipids. It was observed that bioaugmentation contributed to the highest diesel oil biodegradation efficiency, whereas the addition of rhamnolipids did not notably influence the treatment process.

  7. Kaolinite flocculation induced by smectite addition - a transmission X-ray microscopic study.

    PubMed

    Zbik, Marek S; Song, Yen-Fang; Frost, Ray L

    2010-09-01

    The influence of smectite addition on kaolinite suspensions in water was investigated by transmission X-ray microscopy (TXM) and Scanning Electron Microscopy (SEM). Sedimentation test screening was also conducted. Micrographs were processed by the STatistic IMage Analysing (STIMAN) program and structural parameters were calculated. From the results of the sedimentation tests important influences of small smectite additions to about 3wt.% on kaolinite suspension flocculation has been found. In order to determine the reason for this smectite impact on kaolinite suspension, macroscopic behaviour micro-structural examination using Transmission X-ray Microscope (TXM) and SEM has been undertaken. TXM & SEM micrographs of freeze-dried kaolinite-smectite suspensions with up to 20% smectite showed a high degree of orientation of the fabric made of highly oriented particles and greatest density when 3wt.% of smectite was added to the 10wt.% dense kaolinite suspension. In contrast, suspensions containing pure kaolinite do not show such platelet mutual orientation but homogenous network of randomly oriented kaolinite platelets. This suggests that in kaolinite-smectite suspensions, smectite forms highly oriented basic framework into which kaolinite platelets may bond in face to face preferential contacts strengthening structure and allowing them to show plastic behaviour which is cause of platelets orientation. PMID:20621806

  8. Excitotoxic food additives--relevance of animal studies to human safety.

    PubMed

    Olney, J W

    1984-01-01

    Evidence is reviewed supporting the view that excitotoxic food additives pose a significant hazard to the developing nervous system of young children. The following points are stressed: (1) although blood-brain barriers protect most central neurons from excitotoxins, certain brain regions lack such protection (a characteristic common to all vertebrate species); (2) regardless of species, it requires only a transient increase in blood excitotoxin levels for neurons in unprotected brain regions to be "silently" destroyed; (3) humans may be at particularly high risk for this kind of brain damage, since ingestion of a given amount of excitotoxin causes much higher blood excitotoxin levels in humans than in other species; (4) in addition to the heightened risk on a species basis, risk may be further increased for certain consumer sub-populations due to youth, disease or genetic factors; (5) despite these reasons for maintaining a wide margin of safety in the use of excitotoxins in foods, no safety margin is currently being observed, i.e., a comparative evaluation of animal (extensive) and human (limited) data supports the conclusion that excitotoxins, as used in foods today, may produce blood elevations high enough to cause damage to the nervous system of young children, damage which is not detectable at the time of occurrence but which may give rise to subtle disturbances in neuroendocrine function in adolescence and/or adulthood.

  9. Fundamental studies with a monodisperse aerosol-based liquid chromatography/mass spectrometry interface (MAGIC-LC/MS): Progress report, September 1, 1985-August 31, 1988

    SciTech Connect

    Browner, R.F.

    1988-05-01

    Technical advances have been made through a number of careful and detailed studies of fundamental processes occurring within the interface. These have led to great improvements in the performance of the interface, many of which are detailed below. Of particular importance has been an improvement in detection capabilities, allowing full-scan (40--400 daltons) electron impact mass spectra to be obtained with only approximately 5 ng of material injected on column. Selected ion monitoring gives detection limits in the range of 100 pg. These figures are particularly noteworthy because they represent values within a factor of 3 of the lowest detection limits possible with the same instrument when used in a GC/MS mode. The full range of compound types accessible with the MAGIC-LC/MS interface has not been fully investigated. In general terms, all compounds which are known to be capable of generating EI and CI spectra and which have been tried with the interface have generated good quality spectra. These include carbamate and triazine pesticides, phenyl urea herbicides, polynuclear aromatic hydrocarbons, plant alkaloids, antioxidants and EPA Appendix 8 compounds. Compounds known not to generate EI spectra, such as simple sugars and certain azo dyes, predictably do not generate spectra with the current system. The primary mode of ion formation appears to be through a flash vaporization step in the ion source, followed by EI or CI ionization, as selected. It is possible to generate good searchable EI spectra with strong molecular ions even for quite involatile species. An example is provided by reserpine, with a molecular weight of 608 daltons, which generates a searchable EI spectrum with a strong molecular ion at m/z 608. 11 refs.

  10. Additive Manufacturing of a Microbial Fuel Cell--A detailed study.

    PubMed

    Calignano, Flaviana; Tommasi, Tonia; Manfredi, Diego; Chiolerio, Alessandro

    2015-01-01

    In contemporary society we observe an everlasting permeation of electron devices, smartphones, portable computing tools. The tiniest living organisms on Earth could become the key to address this challenge: energy generation by bacterial processes from renewable stocks/waste through devices such as microbial fuel cells (MFCs). However, the application of this solution was limited by a moderately low efficiency. We explored the limits, if any, of additive manufacturing (AM) technology to fabricate a fully AM-based powering device, exploiting low density, open porosities able to host the microbes, systems easy to fuel continuously and to run safely. We obtained an optimal energy recovery close to 3 kWh m(-3) per day that can power sensors and low-power appliances, allowing data processing and transmission from remote/harsh environments.

  11. Additive Manufacturing of a Microbial Fuel Cell—A detailed study

    PubMed Central

    Calignano, Flaviana; Tommasi, Tonia; Manfredi, Diego; Chiolerio, Alessandro

    2015-01-01

    In contemporary society we observe an everlasting permeation of electron devices, smartphones, portable computing tools. The tiniest living organisms on Earth could become the key to address this challenge: energy generation by bacterial processes from renewable stocks/waste through devices such as microbial fuel cells (MFCs). However, the application of this solution was limited by a moderately low efficiency. We explored the limits, if any, of additive manufacturing (AM) technology to fabricate a fully AM-based powering device, exploiting low density, open porosities able to host the microbes, systems easy to fuel continuously and to run safely. We obtained an optimal energy recovery close to 3 kWh m−3 per day that can power sensors and low-power appliances, allowing data processing and transmission from remote/harsh environments. PMID:26611142

  12. Additive Manufacturing of a Microbial Fuel Cell—A detailed study

    NASA Astrophysics Data System (ADS)

    Calignano, Flaviana; Tommasi, Tonia; Manfredi, Diego; Chiolerio, Alessandro

    2015-11-01

    In contemporary society we observe an everlasting permeation of electron devices, smartphones, portable computing tools. The tiniest living organisms on Earth could become the key to address this challenge: energy generation by bacterial processes from renewable stocks/waste through devices such as microbial fuel cells (MFCs). However, the application of this solution was limited by a moderately low efficiency. We explored the limits, if any, of additive manufacturing (AM) technology to fabricate a fully AM-based powering device, exploiting low density, open porosities able to host the microbes, systems easy to fuel continuously and to run safely. We obtained an optimal energy recovery close to 3 kWh m-3 per day that can power sensors and low-power appliances, allowing data processing and transmission from remote/harsh environments.

  13. Preliminary study of neutron absorption by concrete with boron carbide addition

    NASA Astrophysics Data System (ADS)

    Abdullah, Yusof; Ariffin, Fatin Nabilah Tajul; Hamid, Roszilah; Yusof, Mohd Reusmaazran; Zali, Nurazila Mat; Ahmad, Megat Harun Al Rashid Megat; Yazid, Hafizal; Ahmad, Sahrim; Mohamed, Abdul Aziz

    2014-02-01

    Concrete has become a conventional material in construction of nuclear reactor due to its properties like safety and low cost. Boron carbide was added as additives in the concrete construction as it has a good neutron absorption property. The sample preparation for concrete was produced with different weight percent of boron carbide powder content. The neutron absorption rate of these samples was determined by using a fast neutron source of Americium-241/Be (Am-Be 241) and detection with a portable backscattering neutron detector. Concrete with 20 wt % of boron carbide shows the lowest count of neutron transmitted and this indicates the most neutrons have been absorbed by the concrete. Higher boron carbide content may affect the concrete strength and other properties.

  14. Sulphur diffusion in β-NiAl and effect of Pt additive: an ab initio study

    NASA Astrophysics Data System (ADS)

    Chen, Kuiying

    2016-02-01

    Diffusivities of detrimental impurity sulfur (S) in stoichiometric and Pt doped β-NiAl were evaluated using density functional theory calculations. The apparent activation energy and the pre-exponential factor of diffusivity via the next nearest neighbour (NNN) and interstitial jumps were evaluated to identify possible preferred diffusion mechanism(s). By calculating the electron localization function (ELF), the bonding characteristics of S with its surrounding atoms were assessed for the diffusion process. By comparison with the experimental results, the S diffusion through the NNN vacancy-mediated mechanism is found to be favoured. Addition of Pt in β-NiAl was found to significantly reduce the S diffusivity, and an associated electronic effect was explored. The elucidation of the above mechanisms may shed light on the development of new Pt-modified doped β-NiAl bond coats that can extend the life of oxidation resistant and thermal barrier coatings.

  15. Preliminary study of neutron absorption by concrete with boron carbide addition

    SciTech Connect

    Abdullah, Yusof Yusof, Mohd Reusmaazran; Zali, Nurazila Mat; Ahmad, Megat Harun Al Rashid Megat; Yazid, Hafizal; Ariffin, Fatin Nabilah Tajul; Ahmad, Sahrim; Hamid, Roszilah; Mohamed, Abdul Aziz

    2014-02-12

    Concrete has become a conventional material in construction of nuclear reactor due to its properties like safety and low cost. Boron carbide was added as additives in the concrete construction as it has a good neutron absorption property. The sample preparation for concrete was produced with different weight percent of boron carbide powder content. The neutron absorption rate of these samples was determined by using a fast neutron source of Americium-241/Be (Am-Be 241) and detection with a portable backscattering neutron detector. Concrete with 20 wt % of boron carbide shows the lowest count of neutron transmitted and this indicates the most neutrons have been absorbed by the concrete. Higher boron carbide content may affect the concrete strength and other properties.

  16. THERMODYNAMIC STUDY OF THE NICKEL ADDITION IN ZINC HOT-DIP GALVANIZING BATHS

    SciTech Connect

    Pistofidis, N.; Vourlias, G.

    2010-01-21

    A usual practice during zinc hot-dip galvanizing is the addition of nickel in the liquid zinc which is used to inhibit the Sandelin effect. Its action is due to the fact that the zeta(zeta) phase of the Fe-Zn system is replaced by the TAU(tau) phase of the Fe-Zn-Ni system. In the present work an attempt is made to explain the formation of the TAU phase with thermodynamics. For this reason the Gibbs free energy changes for TAU and zeta phases were calculated. The excess free energy for the system was calculated with the Redlich-Kister polyonyme. From this calculation it was deduced that the Gibbs energy change for the tau phase is negative. As a result its formation is spontaneous.

  17. Fundamentals of phosphate transfer.

    PubMed

    Kirby, Anthony J; Nome, Faruk

    2015-07-21

    Historically, the chemistry of phosphate transfer-a class of reactions fundamental to the chemistry of Life-has been discussed almost exclusively in terms of the nucleophile and the leaving group. Reactivity always depends significantly on both factors; but recent results for reactions of phosphate triesters have shown that it can also depend strongly on the nature of the nonleaving or "spectator" groups. The extreme stabilities of fully ionised mono- and dialkyl phosphate esters can be seen as extensions of the same effect, with one or two triester OR groups replaced by O(-). Our chosen lead reaction is hydrolysis-phosphate transfer to water: because water is the medium in which biological chemistry takes place; because the half-life of a system in water is an accepted basic index of stability; and because the typical mechanisms of hydrolysis, with solvent H2O providing specific molecules to act as nucleophiles and as general acids or bases, are models for reactions involving better nucleophiles and stronger general species catalysts. Not least those available in enzyme active sites. Alkyl monoester dianions compete with alkyl diester monoanions for the slowest estimated rates of spontaneous hydrolysis. High stability at physiological pH is a vital factor in the biological roles of organic phosphates, but a significant limitation for experimental investigations. Almost all kinetic measurements of phosphate transfer reactions involving mono- and diesters have been followed by UV-visible spectroscopy using activated systems, conveniently compounds with good leaving groups. (A "good leaving group" OR* is electron-withdrawing, and can be displaced to generate an anion R*O(-) in water near pH 7.) Reactivities at normal temperatures of P-O-alkyl derivatives-better models for typical biological substrates-have typically had to be estimated: by extended extrapolation from linear free energy relationships, or from rate measurements at high temperatures. Calculation is free

  18. Fundamental studies in the molecular basis of laser-induced retinal damage. Annual report, 1 May 1985-30 April 1986

    SciTech Connect

    Lewis, A.

    1986-12-31

    Progress on the fundamental effects of femtosecond laser pulses with retinal pigments, new insights into the detailed interactions of light with photoreceptor cells, and tremendous advances in new forms of super-resolution microscopy are discussed. The common Nd:YAG laser pumping a dye laser is used.

  19. Professional Competence Development of the Social Work Specialists in the Period of Study in the System of Additional Education

    ERIC Educational Resources Information Center

    Davletkaliev, Denis Kuanyshevich; Zueva, Natalia Konstantinovna; Lebedeva, Natalya Vasilevna; Mkrtumova, Irina Vladimirovna; Timofeeva, Olga

    2015-01-01

    The goal of this work is the study of psychological-pedagogical approaches to the understanding of the idea of professional competence of social work specialists as well as the role of study in the system of additional educations in professional-personal development of the listeners. In the process of study of this problem we define main…

  20. A systematic study of well-known electrolyte additives in LiCoO2/graphite pouch cells

    NASA Astrophysics Data System (ADS)

    Wang, David Yaohui; Sinha, N. N.; Petibon, R.; Burns, J. C.; Dahn, J. R.

    2014-04-01

    The effectiveness of well-known electrolyte additives singly or in combination on LiCoO2/graphite pouch cells has been systematically investigated and compared using the ultra high precision charger (UHPC) at Dalhousie University and electrochemical impedance spectroscopy (EIS). UHPC studies are believed to identify the best electrolyte additives singly or in combination within a short time period (several weeks). Three parameters: 1) the coulombic efficiency (CE); 2) the charge endpoint capacity slippage (slippage) and 3) the charge transfer resistance (Rct), of LiCoO2/graphite pouch cells with different electrolyte additives singly or in combination were measured and the results for over 55 additive sets are compared. The experimental results suggest that a combination of electrolyte additives can be more effective than a single electrolyte additive. However, of all the additive sets tested, simply using 2 wt.% vinylene carbonate yielded cells very competitive in CE, slippage and Rct. It is hoped that this comprehensive report can be used as a guide and reference for the study of other electrolyte additives singly or in combination.

  1. Fundamentals of Refrigeration.

    ERIC Educational Resources Information Center

    Sutliff, Ronald D.; And Others

    This self-study course is designed to familiarize Marine enlisted personnel with the principles of the refrigeration process. The course contains five study units. Each study unit begins with a general objective, which is a statement of what the student should learn from the unit. The study units are divided into numbered work units, each…

  2. Spectroscopic Evidence for Covalent Binding of Sulfadiazine to Natural Soils via 1,4-nucleophilic addition (Michael Type Addition) studied by Spin Labeling ESR

    NASA Astrophysics Data System (ADS)

    Aleksandrova, Olga

    2015-04-01

    Among different classes of veterinary pharmaceuticals, Sulfadiazine (SDZ) is widely used in animal husbandry. Its residues were detected in different environmental compartments. However, soil is a hot spot for SDZ as it receives a large portion of excreted compounds through the application of manure during soil fertilization. Ample studies on the fate of SDZ in soils showed that a large portion forms nonextractable residues (NER) along with transformation products and a low mineralization (Mueller et al., 2013). A common observation was an initially fast formation of NER up to 10% of the applied amount promptly after the application of SDZ to soil, and this portion increased up to 50% within a few days (Mueller et al., 2013; Nowak et al., 2011). A common finding for SDZ, as for other sulfonamides, was biphasic kinetics of the formation of NER, which was attributed to the occurrence of two reaction processes: a rapid, often reversible process and a slower, irreversible process (Weber et al., 1996). A single-phase reaction process was also established under anaerobic treatment (Gulkowska et al., 2014). A major focus of this work is to elucidate a reaction mechanism of covalent binding of SDZ to soil that is currently required to estimate a risk of NER formed by SDZ in soils for human health. Taking into account a key role of the amine functional groups of SDZ on its reactivity in soil, nitroxide radicals with the sewed aromatic or aliphatic amines labeled soil samples and then, were investigated by means of ESR spectroscopy. 2,5,5-Trimethyl-2-(3-aminophenyl)pyrrolidin-1-yloxy and 4-amino-2,2,6,6-Tetramethylpiperidin-1-oxyl modeled decomposition products of SDZ with the aromatic and aliphatic amines, respectively. The application of the defined combination of both spin labels (SL) to different soils well simulated a change of a paramagnetic signal of soil organic radicals interacted with SDZ. After their application to soil, SL were found in soil sites characterized

  3. Spectroscopic Evidence for Covalent Binding of Sulfadiazine to Natural Soils via 1,4-nucleophilic addition (Michael Type Addition) studied by Spin Labeling ESR

    NASA Astrophysics Data System (ADS)

    Aleksandrova, Olga

    2015-04-01

    Among different classes of veterinary pharmaceuticals, Sulfadiazine (SDZ) is widely used in animal husbandry. Its residues were detected in different environmental compartments. However, soil is a hot spot for SDZ as it receives a large portion of excreted compounds through the application of manure during soil fertilization. Ample studies on the fate of SDZ in soils showed that a large portion forms nonextractable residues (NER) along with transformation products and a low mineralization (Mueller et al., 2013). A common observation was an initially fast formation of NER up to 10% of the applied amount promptly after the application of SDZ to soil, and this portion increased up to 50% within a few days (Mueller et al., 2013; Nowak et al., 2011). A common finding for SDZ, as for other sulfonamides, was biphasic kinetics of the formation of NER, which was attributed to the occurrence of two reaction processes: a rapid, often reversible process and a slower, irreversible process (Weber et al., 1996). A single-phase reaction process was also established under anaerobic treatment (Gulkowska et al., 2014). A major focus of this work is to elucidate a reaction mechanism of covalent binding of SDZ to soil that is currently required to estimate a risk of NER formed by SDZ in soils for human health. Taking into account a key role of the amine functional groups of SDZ on its reactivity in soil, nitroxide radicals with the sewed aromatic or aliphatic amines labeled soil samples and then, were investigated by means of ESR spectroscopy. 2,5,5-Trimethyl-2-(3-aminophenyl)pyrrolidin-1-yloxy and 4-amino-2,2,6,6-Tetramethylpiperidin-1-oxyl modeled decomposition products of SDZ with the aromatic and aliphatic amines, respectively. The application of the defined combination of both spin labels (SL) to different soils well simulated a change of a paramagnetic signal of soil organic radicals interacted with SDZ. After their application to soil, SL were found in soil sites characterized

  4. Sensitization to Food Additives in Patients with Allergy: A Study Based on Skin Test and Open Oral Challenge.

    PubMed

    Moghtaderi, Mozhgan; Hejrati, Zinatosadat; Dehghani, Zahra; Dehghani, Faranak; Kolahi, Niloofar

    2016-06-01

    There has been a great increase in the consumption of various food additives in recent years. The purpose of this study was to identify the incidence of sensitization to food additives by using skin prick test in patients with allergy and to determine the concordance rate between positive skin tests and oral challenge in hypersensitivity to additives. This cross-sectional study included 125 (female 71, male 54) patients aged 2-76 years with allergy and 100 healthy individuals. Skin tests were performed in both patient and control groups with 25 fresh food additives. Among patients with allergy, 22.4% showed positive skin test at least to one of the applied materials. Skin test was negative to all tested food additives in control group. Oral food challenge was done in 28 patients with positive skin test, in whom 9 patients showed reaction to culprit (Concordance rate=32.1%). The present study suggested that about one-third of allergic patients with positive reaction to food additives showed positive oral challenge; it may be considered the potential utility of skin test to identify the role of food additives in patients with allergy.

  5. Sensitization to Food Additives in Patients with Allergy: A Study Based on Skin Test and Open Oral Challenge.

    PubMed

    Moghtaderi, Mozhgan; Hejrati, Zinatosadat; Dehghani, Zahra; Dehghani, Faranak; Kolahi, Niloofar

    2016-06-01

    There has been a great increase in the consumption of various food additives in recent years. The purpose of this study was to identify the incidence of sensitization to food additives by using skin prick test in patients with allergy and to determine the concordance rate between positive skin tests and oral challenge in hypersensitivity to additives. This cross-sectional study included 125 (female 71, male 54) patients aged 2-76 years with allergy and 100 healthy individuals. Skin tests were performed in both patient and control groups with 25 fresh food additives. Among patients with allergy, 22.4% showed positive skin test at least to one of the applied materials. Skin test was negative to all tested food additives in control group. Oral food challenge was done in 28 patients with positive skin test, in whom 9 patients showed reaction to culprit (Concordance rate=32.1%). The present study suggested that about one-third of allergic patients with positive reaction to food additives showed positive oral challenge; it may be considered the potential utility of skin test to identify the role of food additives in patients with allergy. PMID:27424134

  6. Driveline Fundamentals and Lubrication

    NASA Astrophysics Data System (ADS)

    Joseph, I.

    The various gear types and automotive transmissions in drive trains are described. The need for automotive differential axle gears is demonstrated. SAE gear lubricant classifications are related to performance specifications. Automatic transmission fluids, ATFs, are described together with agricultural and off-highway fluids. Generic formulations of driveline fluids are discussed in terms of their tribology and performance and also the contribution of various additive classes to that performance. The main functions of manual gearbox, automatic transmission and axle lubricants are described. General trends and emerging technologies in drive train components are discussed in terms of the requirements placed on the lubricant, evolution in transmission technologies and relative market penetration.

  7. Fundamentals of flow measurement

    SciTech Connect

    De Carlo, J.P.

    1984-01-01

    This book provides an understanding of flow measurement methods. Twelve separate units are designed to introduce the two basic approaches to flow measurement. ''Energy Extractive'' and ''Energy Additive,'' the general classes and types of flowmeters, the terminology associated with flow measurement, special techniques, mass flow measurement and the methodology for flowmeter selection. It explains the basic approaches to flow measurement and the different classes of flowmeters; flowmeter terminology; the basic theory of operation of different flowmeters; choosing the correct approach, class type, and particular device to satisfy the specified requirement; and sizing a flowmeter to satisfy the requirements of an installation.

  8. Te Rita Papesch: Case Study of an Exemplary Learner of Maori as an Additional Language

    ERIC Educational Resources Information Center

    Ratima, Matiu Tai; Papesch, Te Rita

    2014-01-01

    This paper presents a case study of the life experiences of one exemplar adult second language Maori learner--Te Rita Papesch. Te Rita was one of 17 participants who were interviewed as a part of the first author's PhD study which sought to answer the question: what factors lead to the development of proficiency in te reo Maori amongst adult…

  9. Study on additional carrier sensing for IEEE 802.15.4 wireless sensor networks.

    PubMed

    Lee, Bih-Hwang; Lai, Ruei-Lung; Wu, Huai-Kuei; Wong, Chi-Ming

    2010-01-01

    Wireless sensor networks based on the IEEE 802.15.4 standard are able to achieve low-power transmissions in the guise of low-rate and short-distance wireless personal area networks (WPANs). The slotted carrier sense multiple access with collision avoidance (CSMA/CA) is used for contention mechanism. Sensor nodes perform a backoff process as soon as the clear channel assessment (CCA) detects a busy channel. In doing so they may neglect the implicit information of the failed CCA detection and further cause the redundant sensing. The blind backoff process in the slotted CSMA/CA will cause lower channel utilization. This paper proposes an additional carrier sensing (ACS) algorithm based on IEEE 802.15.4 to enhance the carrier sensing mechanism for the original slotted CSMA/CA. An analytical Markov chain model is developed to evaluate the performance of the ACS algorithm. Both analytical and simulation results show that the proposed algorithm performs better than IEEE 802.15.4, which in turn significantly improves throughput, average medium access control (MAC) delay and power consumption of CCA detection.

  10. Chromosome studies in the aquatic monocots of Myanmar: A brief review with additional records.

    PubMed

    Ito, Yu; Tanaka, Nobuyuki

    2014-01-01

    Myanmar (Burma) constitutes a significant component of the Indo-Myanmar biodiversity hotspot, with elements of the Indian, the Indochina, and the Sino-Japanese floristic regions, yet thus far only a few reliable sources of the country's flora have been available. As a part of a contribution for the floristic inventory of Myanmar, since it is important in a floristic survey to obtain as much information as possible, in addition to previous two reports, here we present three more chromosome counts in the aquatic monocots of Myanmar: Limnocharisflava with 2n = 20, Sagittariatrifolia with 2n = 22 (Alismataceae), and Potamogetondistinctus × Potamogetonnodosus with 2n = 52 (Potamogetonaceae); the third one is new to science. A brief review of cytological researches in the floristic regions' 45 non-hybrid aquatic monocots plus well investigated two inter-specific hybrids that are recorded in Myanmar is given, indicating that the further works with a focus on species in Myanmar that has infra-specific chromosome variation in the floristic regions will address the precise evolutionary history of the aquatic flora of Myanmar.

  11. Numerical study of the effect of water addition on gas explosion.

    PubMed

    Liang, Yuntao; Zeng, Wen

    2010-02-15

    Through amending the SENKIN code of CHEMKIN III chemical kinetics package, a computational model of gas explosion in a constant volume bomb was built, and the detailed reaction mechanism (GRI-Mech 3.0) was adopted. The mole fraction profiles of reactants, some selected free radicals and catastrophic gases in the process of gas explosion were analyzed by this model. Furthermore, through the sensitivity analysis of the reaction mechanism of gas explosion, the dominant reactions that affect gas explosion and the formation of catastrophic gases were found out. At the same time, the inhibition mechanisms of water on gas explosion and the formation of catastrophic gases were analyzed. The results show that the induced explosion time is prolonged, and the mole fractions of reactant species such as CH(4), O(2) and catastrophic gases such as CO, CO(2) and NO are decreased as water is added to the mixed gas. With the water fraction in the mixed gas increasing, the sensitivities of the dominant reactions contributing to CH(4), CO(2) are decreased and the sensitivity coefficients of CH(4), CO and NO mole fractions are also decreased. The inhibition of gas explosion with water addition can be ascribed to the significant decrease of H, O and OH in the process of gas explosion due to the water presence. PMID:19811873

  12. Generalized linear and generalized additive models in studies of species distributions: Setting the scene

    USGS Publications Warehouse

    Guisan, A.; Edwards, T.C.; Hastie, T.

    2002-01-01

    An important statistical development of the last 30 years has been the advance in regression analysis provided by generalized linear models (GLMs) and generalized additive models (GAMs). Here we introduce a series of papers prepared within the framework of an international workshop entitled: Advances in GLMs/GAMs modeling: from species distribution to environmental management, held in Riederalp, Switzerland, 6-11 August 2001. We first discuss some general uses of statistical models in ecology, as well as provide a short review of several key examples of the use of GLMs and GAMs in ecological modeling efforts. We next present an overview of GLMs and GAMs, and discuss some of their related statistics used for predictor selection, model diagnostics, and evaluation. Included is a discussion of several new approaches applicable to GLMs and GAMs, such as ridge regression, an alternative to stepwise selection of predictors, and methods for the identification of interactions by a combined use of regression trees and several other approaches. We close with an overview of the papers and how we feel they advance our understanding of their application to ecological modeling. ?? 2002 Elsevier Science B.V. All rights reserved.

  13. Exploratory studies of extended storage of apheresis platelets in a platelet additive solution (PAS).

    PubMed

    Slichter, Sherrill J; Corson, Jill; Jones, Mary Kay; Christoffel, Todd; Pellham, Esther; Bailey, S Lawrence; Bolgiano, Doug

    2014-01-01

    To evaluate the poststorage viability of apheresis platelets stored for up to 18 days in 80% platelet additive solution (PAS)/20% plasma, 117 healthy subjects donated platelets using the Haemonetics MCS+, COBE Spectra (Spectra), or Trima Accel (Trima) systems. Control platelets from the same subjects were compared with their stored test PAS platelets by radiolabeling their stored and control platelets with either (51)chromium or (111)indium. Trima platelets met Food and Drug Administration poststorage platelet viability criteria for only 7 days vs almost 13 days for Haemonetics platelets; ie, platelet recoveries after these storage times averaged 44 ± 3% vs 49 ± 3% and survivals were 5.4 ± 0.3 vs 4.6 ± 0.3 days, respectively. The differences in storage duration are likely related to both the collection system and the storage bag. The Spectra and Trima platelets were hyperconcentrated during collection, and PAS was added, whereas the Haemonetics platelets were elutriated with PAS, which may have resulted in less collection injury. When Spectra and Trima platelets were stored in Haemonetics' bags, poststorage viability was significantly improved. Platelet viability is better maintained in vitro than in vivo, allowing substantial increases in platelet storage times. However, implementation will require resolution of potential bacterial overgrowth during storage.

  14. Chromosome studies in the aquatic monocots of Myanmar: A brief review with additional records

    PubMed Central

    2014-01-01

    Abstract Myanmar (Burma) constitutes a significant component of the Indo-Myanmar biodiversity hotspot, with elements of the Indian, the Indochina, and the Sino-Japanese floristic regions, yet thus far only a few reliable sources of the country's flora have been available. As a part of a contribution for the floristic inventory of Myanmar, since it is important in a floristic survey to obtain as much information as possible, in addition to previous two reports, here we present three more chromosome counts in the aquatic monocots of Myanmar: Limnocharis flava with 2n = 20, Sagittaria trifolia with 2n = 22 (Alismataceae), and Potamogeton distinctus × Potamogeton nodosus with 2n = 52 (Potamogetonaceae); the third one is new to science. A brief review of cytological researches in the floristic regions' 45 non-hybrid aquatic monocots plus well investigated two inter-specific hybrids that are recorded in Myanmar is given, indicating that the further works with a focus on species in Myanmar that has infra-specific chromosome variation in the floristic regions will address the precise evolutionary history of the aquatic flora of Myanmar. PMID:24891826

  15. Multi-spectroscopic DNA interaction studies of sunset yellow food additive.

    PubMed

    Kashanian, Soheila; Heidary Zeidali, Sahar; Omidfar, Kobra; Shahabadi, Nahid

    2012-12-01

    The use of food dyes is at least controversial due to their essential role. Synthetic color food additives occupy an important place in the food industry. Moreover many of them have been related to health problems mainly in children that are considered the most vulnerable group. The purpose of this work is to present spectrophotometric methods to analyze the interaction of native calf thymus DNA (CT-DNA) with sunset yellow (SY) at physiological pH. Considerable hyperchromism and no red shift with an intrinsic binding constant of 7 × 10(4 )M(-1) were observed in UV absorption band of SY. Binding constants of DNA with complex were calculated at different temperatures. Slow increase in specific viscosity of DNA, induced circular dichroism spectral changes, and no significant changes in the fluorescence of neutral red-DNA solutions in the presence of SY suggest that this molecule interacts with CT-DNA via groove binding mode. Furthermore, the enthalpy and entropy of the reaction between SY and CT-DNA showed that the reaction is exothermic and enthalpy favored (∆H = -58.19 kJ mol(-1); ΔS = -274.36 kJ mol(-1) ) which are other evidences to indicate that van der Waals interactions and hydrogen bonding are the main running forces in the binding of the mentioned molecule and mode of interaction with DNA.

  16. A study of alternative metal particle structures and mixtures for dental amalgams based on mercury additions.

    PubMed

    Marquez, J A; Murr, L E; Agüero, V

    2000-08-01

    The perception that mercury in dental amalgam is toxic to the human organism has prompted worldwide efforts by the scientific community to develop alternative amalgam-like materials that utilize little or no mercury. In this investigation, an attempt is made to develop a new dental alloy system by adding liquid mercury to silver-coated Ag4Sn intermetallic particles in lesser amounts than are used in conventional amalgam alloys. An effort to precipitate the important eta-prime (Cu6Sn5) phase was made by adding pure Cu and Sn powders to the alloy formulation during trituration. Tytin a popular Ag-Sn-Cu single-composition, spray-atomized conventional dental alloy was used as the control to obtain baseline data for comparisons of microstructures and mechanical properties. Amalgamation of the coated particles with mercury, with or without the addition of Cu and Sn powders, mostly produced specimens with chemically non-coherent microstructures that were relatively weak in compression. These results were due, in part, to mercury's inability to chemically wet the Ag-coated particles and Cu and Sn powders because of naturally occurring surface oxide films. The strongest specimens tested had silver dendritic coatings, resulting in compression strength values up to 40% of the control's. Their higher strength is attributed to mechanical interlocking at the particle/matrix interfaces.

  17. Additional road markings as an indication of speed limits: results of a field experiment and a driving simulator study.

    PubMed

    Daniels, Stijn; Vanrie, Jan; Dreesen, An; Brijs, Tom

    2010-05-01

    Although speed limits are indicated by road signs, road users are not always aware, while driving, of the actual speed limit on a given road segment. The Roads and Traffic Agency developed additional road markings in order to support driver decisions on speed on 70 km/h roads in Flanders-Belgium. In this paper the results are presented of two evaluation studies, both a field study and a simulator study, on the effects of the additional road markings on speed behaviour. The results of the field study showed no substantial effect of the markings on speed behaviour. Neither did the simulator study, with slightly different stimuli. Nevertheless an effect on lateral position was noticed in the simulator study, showing at least some effect of the markings. The role of conspicuity of design elements and expectations towards traffic environments is discussed. Both studies illustrate well some strengths and weaknesses of observational field studies compared to experimental simulator studies.

  18. Voice measures of workload in the advanced flight deck: Additional studies

    NASA Technical Reports Server (NTRS)

    Schneider, Sid J.; Alpert, Murray

    1989-01-01

    These studies investigated acoustical analysis of the voice as a measure of workload in individual operators. In the first study, voice samples were recorded from a single operator during high, medium, and low workload conditions. Mean amplitude, frequency, syllable duration, and emphasis all tended to increase as workload increased. In the second study, NASA test pilots performed a laboratory task, and used a flight simulator under differing work conditions. For two of the pilots, high workload in the simulator brought about greater amplitude, peak duration, and stress. In both the laboratory and simulator tasks, high workload tended to be associated with more statistically significant drop-offs in the acoustical measures than were lower workload levels. There was a great deal of intra-subject variability in the acoustical measures. The results suggested that in individual operators, increased workload might be revealed by high initial amplitude and frequency, followed by rapid drop-offs over time.

  19. Study on Type C Coal Fly ash as an Additive to Molding Sand for Steel Casting

    NASA Astrophysics Data System (ADS)

    Palaniappan, Jayanthi

    2016-05-01

    Study of physio-chemical properties studies such as granulometric analysis, moisture, X ray fluorescence etc. were performed with Type C coal—combustion fly ash to investigate their potential as a distinct option for molding sand in foundry, thereby reducing the dependency on latter. Technological properties study such as compressive strength, tensile strength, permeability and compaction of various compositions of fly ash molding sand (10, 20 and 30 % fly ash substitute to chemically bonded sand) were performed and compared with silica molding sand. Steel casting production using this fly ash molding sand was done and the casting surface finish and typical casting parameters were assessed. It was noted that a good quality steel casting could be produced using type C fly ash molding sand, which effectively replaced 20 % of traditional molding sand and binders thereby providing greater financial profits to the foundry and an effective way of fly ash utilization (waste management).

  20. Additional Study of Water Droplet Median Volume Diameter (MVD) Effects on Ice Shapes

    NASA Technical Reports Server (NTRS)

    Tsao, Jen-Ching; Anderson, David N.

    2005-01-01

    This paper reports the result of an experimental study in the NASA Glenn Icing Research Tunnel (IRT) to evaluate how well the MVD-independent effect identified previously might apply to SLD conditions in rime icing situations. Models were NACA 0012 wing sections with chords of 53.3 and 91.4 cm. Tests were conducted with a nominal airspeed of 77 m/s (150 kt) and a number of MVD's ranging from 15 to 100 m with LWC of 0.5 to 1 g/cu m. In the present study, ice shapes recorded from past studies and recent results at SLD and Appendix-C conditions are reviewed to show that droplet diameter is not important to rime ice shape for MVD of 30 microns or larger, but for less than 30 m drop sizes a rime ice shape transition from convex to wedge to spearhead type ice shape is observed.