Apparatus and process for passivating an SRF cavity

DOEpatents

Myneni, Ganapati Rao; Wallace, John P

2014-12-02

An apparatus and process for the production of a niobium cavity exhibiting high quality factors at high gradients is provided. The apparatus comprises a first chamber positioned within a second chamber, an RF generator and vacuum pumping systems. The process comprises placing the niobium cavity in a first chamber of the apparatus; thermally treating the cavity by high temperature in the first chamber while maintaining high vacuum in the first and second chambers; and applying a passivating thin film layer to a surface of the cavity in the presence of a gaseous mixture and an RF field. Further a niobium cavity exhibiting high quality factors at high gradients produced by the method of the invention is provided.

Hierarchic spatio-temporal dynamics in glycolysis

NASA Astrophysics Data System (ADS)

Shinjyo, Takahiro; Nakagawa, Yoshiyuki; Ueda, Tetsuo

Yeast extracts exhibit oscillations when the glycolytic system is far away from equilibrium. Spatio-temporal dynamics in this system was studied in the newly developed gel as well as in the solution. Small regions (about 10 um) with very complex shape with high or low concentrations of NADH appeared, and upon these small structures large-scale dynamics were superimposed. Concentration waves propagated, and the source of wave was induced by contact with high ADP. Sink of waves was generated by contacting the reaction gel to two small gels rich in ADP. Upon these spatio-temporal dynamics were superimposed much slower global oscillations throughout the system with a period of about 40 min. Similar dynamics was seen in a solution of yeast extract, but the size of domains was about ten times larger than that in the gel. In this way, the multi-enzyme system of glycolysis exhibits self-organization of hierarchy in spatio-temporal dynamics.

Moderate pressure massage elicits a parasympathetic nervous system response.

PubMed

Diego, Miguel A; Field, Tiffany

2009-01-01

Twenty healthy adults were randomly assigned to a moderate pressure or a light pressure massage therapy group, and EKGs were recorded during a 3-min baseline, during the 15-min massage period and during a 3-min postmassage period. EKG data were then used to derive the high frequency (HF), low frequency (LF) components of heart rate variability and the low to high frequency ratio (LF/HF) as noninvasive markers of autonomic nervous system activity. The participants who received the moderate pressure massage exhibited a parasympathetic nervous system response characterized by an increase in HF, suggesting increased vagal efferent activity and a decrease in the LF/HF ratio, suggesting a shift from sympathetic to parasympathetic activity that peaked during the first half of the massage period. On the other hand, those who received the light pressure massage exhibited a sympathetic nervous system response characterized by decreased HF and increased LF/HF.

Starship 2040 Exhibit

NASA Technical Reports Server (NTRS)

2002-01-01

This photograph shows Justin Varnadore, son of a Marshall TV employee, at the controls of one of the many displays within the Starship 2040 exhibit on display at Joe Davis Stadium in Huntsville, Alabama. Developed by the Space Transportation Directorate at Marshall Space Flight Center (MSFC), the Starship 2040 exhibit is housed in a 48-ft (14.6-m) tractor and trailer rig, permitting it to travel around the Nation, demonstrating NASA's vision of what commercial spaceflight might be like 40 years from now. All the irnovations suggested aboard the exhibit (automated vehicle health monitoring systems, high-energy propulsion drive, navigational aids, and emergency and safety systems) are based on concepts and technologies now being studied at NASA Centers and partner institutions around the Nation. NASA is the Nation's premier agency for development of the space transportation system, including future-generation reusable launch vehicles. Such systems, the keys to a 'real' Starship 2040, require revolutionary advances in critical aerospace technologies, from thermal, magnetic, chemical, and propellantless propulsion systems to new energy sources such as space solar power or antimatter propulsion. These and other advances are now being studied, developed, and tested at NASA field centers and partner institutions all over the Nation.

Around Marshall

NASA Image and Video Library

2001-01-01

This photograph shows the Starship 2040 leaving the Marshall Space Flight Center (MSFC) for the exhibit site. Developed by the Space Transportation Directorate at MSFC, the Starship 2040 exhibit is housed in a 48-ft (14.6-m) tractor and trailer rig, permitting it to travel around the Nation, demonstrating NASA's vision of what commercial spaceflight might be like 40 years from now. All the irnovations suggested aboard the exhibit, automated vehicle health monitoring systems, high-energy propulsion drive, navigational aids and emergency and safety systems, are based on concepts and technologies now being studied at NASA Centers and partner institutions around the Nation. NASA is the nation's premier agency for development of the space transportation system, including future-generation reusable launch vehicles. Such systems, the keys to a "real" Starship 2040, require revolutionary advances in critical aerospace technologies, from thermal, magnetic, chemical, and propellantless propulsion systems to new energy sources such as space solar power or antimatter propulsion. These and other advances are now being studied, developed, and tested at NASA field centers and partner institutions all over the Nation.

Magnetization at high pressure in CeP

NASA Astrophysics Data System (ADS)

Naka, T.; Matsumoto, T.; Okayama, Y.; Môri, N.; Haga, Y.; Suzuki, T.

1995-02-01

We have investigated the pressure dependence of magnetization below 60 K up to 1.6 GPa in the low-carrier concentration system CeP showing two step transitions at T = TL and TH under high pressure. At high pressure, M( P, T) exhibits a maximum at around the lower transition temperature TL. This behavior implies that the magnetic state changes at TL. The pressure dependence of isothermal magnetization M( P) is different above and below TL. In fact, M( P) below TL exhibits a maximum at around 1.4 GPa, whereas M( P) above TL increases steeply with pressure up to 1.6 GPa.

Thermoplastic adhesives based on 4,4'-isophthaloyldiphthalic anhydride (IDPA)

NASA Technical Reports Server (NTRS)

Progar, Donald J.; Stclair, Terry L.; Pratt, J. Richard

1988-01-01

Thermoplastic polyimides were prepared and evaluated as adhesives. These materials are based on 4,4'-isophthaloyldiphathalic anhydride (IDAP) and either metaphenylene diamine (MPD) or 3,3'-diaminobenzophenone (DBAP). Both polymers exhibit excellent adhesive properties; however, the IDPA-MPD is the more attractive system because of a combination of high mechanical and physical properties as well as being made from commercially attractive monomers. The IDPA-MPD is an isomeric form of the commercially available adhesive and matrix resin, LARC-TPI and both systems have the same glass transition temperature and exhibit similar adhesive properties.

James C. McGroddy Prize Talk: Development and Applications of Bulk Metallic Glasses

NASA Astrophysics Data System (ADS)

Inoue, Akihisa

2009-03-01

We realized, through detailed amorphous material investigations in the 1980's, that a number of metallic glassy alloys of multi-component La-, Mg- and Zr-based systems exhibit a large supercooled-liquid region prior to crystallization. The stabilization phenomenon of these supercooled liquid should enable us to fabricate, by slow cooling processes, bulk metallic glasses (BMGs) with critical diameters larger than several millimeters. Caltech's group also succeeded the fabrication of BMG in Zr-based alloy system in 1993. Since then, much attention has been paid to BMGs because of their novel characteristics in basic science and engineering aspects and new materials science and engineering fields have emerged for BMGs. Based on knowledge obtained thus far, we have successfully developed new BMGs with technologically-important transition metals, such as Zr-, Ti-, Fe-, Co-, Ni- and Cu-based alloys. Currently, the maximum diameter for glass formation reaches 30 mm for Zr- and Cu-based systems, 12 mm for Ti-based system, 18 mm for Fe-Co-based system and 20 mm for Ni-based system, even employing the copper mold casting technique. These large size BMGs possess nearly the same fundamental properties as those of the BMGs with smaller diameters. BMGs with diameters above 10 mm can be formed in Zr-Al-Ni-Cu system with Zr compositions higher than 65 at% and they exhibit excellent properties, such as high Poisson's ratio, high ductility, high fracture toughness, high fatigue strength and high stability of mechanical properties to annealing-induced embrittlement. The new Ti-based BMGs without allergic and toxic elements should exhibit good compatibility to bio-tissues. Applications of BMGs in Fe-, Co-, Ti- and Zr-based systems have advanced many devices including the following; choke coil, power inductor, electro magnetic shielding, magnetic and position sensors, micro-geared motor, pressure sensor, Coriolis flowmeter, surface coating layer, precise polishing medium, magnetic and structural parts in electric magnetic control-type spring drive watches, medical operation instruments and so forth. A. Inoue, Acta Mater., 48(2000), 279-306.

Experimental study of two-dimensional quantum Wigner solid in zero magnetic field

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

Huang, Jian; Pfeiffer, L. N.; West, K. W.

2014-03-31

At temperatures T → 0, strongly interacting two-dimensional (2D) electron systems manifest characteristic insulating behaviors that are key for understanding the nature of the ground state in light of the interplay between disorder and electron-electron interaction. In contrast to the hopping conductance demonstrated in the insulating side of the metal-to-insulator transition, the ultra-high quality 2D systems exhibit nonactivated T-dependence of the conductivity even for dilute carrier concentrations down to 7×10{sup 8} cm{sup −2}. The apparent metal-to-insulator transition (MIT) occurs for a large r{sub s} value around 40 for which a Wigner Crystalllization is expected. The magnetoresistance for a series ofmore » carrier densities in the vicinity of the transition exhibits a characteristic sign change in weak perpendicular magnetic field. Within the Wigner Crystallization regime (with r{sub s} > 40), we report an experimental observation of a characteristic nonlinear threshold behavior from a high-resolution dc dynamical response as an evidence for aWigner crystallization in high-purity GaAs 2D hole systems in zero magnetic field. The system under an increasing current drive exhibits voltage oscillations with negative differential resistance. They confirm the coexistence of a moving crystal along with striped edge states as observed for electrons on helium surfaces. Moreover, the threshold is well below the typical classical levels due to a different pinning and depinning mechanism that is possibly related to quantum processes.« less

Characterization and device applications of ZnO films deposited by high power impulse magnetron sputtering (HiPIMS)

NASA Astrophysics Data System (ADS)

Partridge, J. G.; Mayes, E. L. H.; McDougall, N. L.; Bilek, M. M. M.; McCulloch, D. G.

2013-04-01

ZnO films have been reactively deposited on sapphire substrates at 300 °C using a high impulse power magnetron sputtering deposition system and characterized structurally, optically and electronically. The unintentionally doped n-type ZnO films exhibit high transparency, moderate carrier concentration (˜5 × 1018 cm-3) and a Hall mobility of 8.0 cm2 V-1 s-1, making them suitable for electronic device applications. Pt/ZnO Schottky diodes formed on the HiPIMS deposited ZnO exhibited rectification ratios up to 104 at ±2 V and sensitivity to UV light.

SPIN–SPIN COUPLING IN THE SOLAR SYSTEM

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

Batygin, Konstantin; Morbidelli, Alessandro, E-mail: kbatygin@gps.caltech.edu

The richness of dynamical behavior exhibited by the rotational states of various solar system objects has driven significant advances in the theoretical understanding of their evolutionary histories. An important factor that determines whether a given object is prone to exhibiting non-trivial rotational evolution is the extent to which such an object can maintain a permanent aspheroidal shape, meaning that exotic behavior is far more common among the small body populations of the solar system. Gravitationally bound binary objects constitute a substantial fraction of asteroidal and TNO populations, comprising systems of triaxial satellites that orbit permanently deformed central bodies. In thismore » work, we explore the rotational evolution of such systems with specific emphasis on quadrupole–quadrupole interactions, and show that for closely orbiting, highly deformed objects, both prograde and retrograde spin–spin resonances naturally arise. Subsequently, we derive capture probabilities for leading order commensurabilities and apply our results to the illustrative examples of (87) Sylvia and (216) Kleopatra asteroid systems. Cumulatively, our results suggest that spin–spin coupling may be consequential for highly elongated, tightly orbiting binary objects.« less

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

Becher, P.F.; Sun, E.Y.; Hsueh, C.H.

The development of high strength ({ge} 1 GPa), high toughness ({ge} 10 MPa {radical}m) ceramic systems is being examined using two approaches. In silicon nitride, toughening is achieved by the introduction of large prismatic shaped grains dispersed in a fine grain matrix. For the system examined herein, both the microstructure and the composition must be controlled. A distinctly bimodal distribution of grain diameters combined with controlled yttria to alumina ratio in additives to promote interfacial debonding is required. Using a cermet approach, ductile Ni{sub 3}Al-bonded TiC exhibited toughening due to plastic deformation within the Ni{sub 3}Al binder phase assisted bymore » interfacial debonding and cleavage of TiC grains. The TiC-Ni{sub 3}Al cermets have toughness values equal to those of the WC-Co cermets. Furthermore, the TiC-Ni{sub 3}Al cermets exhibit high strengths that are retained in air to temperatures of {approximately} 1,000 C.« less

Around Marshall

NASA Image and Video Library

2002-06-01

This photograph shows onlookers viewing displays within the Starship 2040 exhibit on display at Joe Davis Stadium in Huntsville, Alabama. Developed by the Space Transportation Directorate at Marshall Space Flight Center (MSFC), the Starship 2040 exhibit is housed in a 48-ft (14.6-m) tractor and trailer rig, permitting it to travel around the Nation, demonstrating NASA's vision of what commercial spaceflight might be like 40 years from now. All the irnovations suggested aboard the exhibit (automated vehicle health monitoring systems, high-energy propulsion drive, navigational aids, and emergency and safety systems) are based on concepts and technologies now being studied at NASA Centers and partner institutions around the Nation. NASA is the Nation's premier agency for development of the space transportation system, including future-generation reusable launch vehicles. Such systems, the keys to a "real" Starship 2040, require revolutionary advances in critical aerospace technologies, from thermal, magnetic, chemical, and propellantless propulsion systems to new energy sources such as space solar power or antimatter propulsion. These and other advances are now being studied, developed, and tested at NASA field centers and partner institutions all over the Nation.

Starship 2040 Exhibit

NASA Technical Reports Server (NTRS)

2002-01-01

This photograph shows the Starship 2040 on display at Joe Davis Stadium in Huntsville, Alabama. Developed by the Space Transportation Directorate at Marshall Space Flight Center (MSFC), the Starship 2040 exhibit is housed in a 48-ft (14.6-m) tractor and trailer rig, permitting it to travel around the Nation, demonstrating NASA's vision of what commercial spaceflight might be like 40 years from now. All the irnovations suggested aboard the exhibit (automated vehicle health monitoring systems, high-energy propulsion drive, navigational aids, and emergency and safety systems) are based on concepts and technologies now being studied at NASA Centers and partner institutions around the Nation. NASA is the Nation's premier agency for development of the space transportation system, including future-generation reusable launch vehicles. Such systems, the keys to a 'real' Starship 2040, require revolutionary advances in critical aerospace technologies, from thermal, magnetic, chemical, and propellantless propulsion systems to new energy sources such as space solar power or antimatter propulsion. These and other advances are now being studied, developed, and tested at NASA field centers and partner institutions all over the Nation.

Imide modified epoxy matrix resins

NASA Technical Reports Server (NTRS)

Scola, D. A.; Pater, R. H.

1981-01-01

High char yield epoxy using novel bisimide amines (BIA's) as curing agents with a state of the art epoxy resin was developed. Stoichiometric quantities of the epoxy resin and the BIA's were studied to determine the cure cycle required for preparation of resin specimens. The bisimide cured epoxies were designated IME's (imide modified epoxy). The physical, thermal and mechanical properties of these novel resins were determined. The levels of moisture absorption exhibited by the bisimide amine cured expoxies (IME's) were considerably lower than the state of the art epoxies. The strain-to-failure of the control resin system was improved 25% by replacement of DDS with 6F-DDS. Each BIA containing resin exhibited twice the char yield of the control resin MY 720/DDS. Graphite fiber reinforced control (C) and IME resins were fabricated and characterized. Two of the composite systems showed superior properties compared to the other Celion 6000/IME composite systems and state of the art graphite epoxy systems. The two systems exhibited excellent wet shear and flexural strengths and moduli at 300 and 350 F.

Vertically Emitting Indium Phosphide Nanowire Lasers.

PubMed

Xu, Wei-Zong; Ren, Fang-Fang; Jevtics, Dimitars; Hurtado, Antonio; Li, Li; Gao, Qian; Ye, Jiandong; Wang, Fan; Guilhabert, Benoit; Fu, Lan; Lu, Hai; Zhang, Rong; Tan, Hark Hoe; Dawson, Martin D; Jagadish, Chennupati

2018-06-13

Semiconductor nanowire (NW) lasers have attracted considerable research effort given their excellent promise for nanoscale photonic sources. However, NW lasers currently exhibit poor directionality and high threshold gain, issues critically limiting their prospects for on-chip light sources with extremely reduced footprint and efficient power consumption. Here, we propose a new design and experimentally demonstrate a vertically emitting indium phosphide (InP) NW laser structure showing high emission directionality and reduced energy requirements for operation. The structure of the laser combines an InP NW integrated in a cat's eye (CE) antenna. Thanks to the antenna guidance with broken asymmetry, strong focusing ability, and high Q-factor, the designed InP CE-NW lasers exhibit a higher degree of polarization, narrower emission angle, enhanced internal quantum efficiency, and reduced lasing threshold. Hence, this NW laser-antenna system provides a very promising approach toward the achievement of high-performance nanoscale lasers, with excellent prospects for use as highly localized light sources in present and future integrated nanophotonics systems for applications in advanced sensing, high-resolution imaging, and quantum communications.

Conclusion

NASA Astrophysics Data System (ADS)

Ivancevic, Vladimir G.; Reid, Darryn J.

2015-11-01

It is often held that things should always be made simple, which presumes that either that they can always be made simple or that all the jetisoned logic doesn't matter anyway. Alledgedly, anything should be explainable so that anyone can understand it. Don't get bogged down in dreary details. It should be effortless for the reader: low-dimensional systems exhibit complex behaviour while high-dimensional systems exhibit simple behaviour (to return to our prolegomonal opening), competition is a universal solution, demand must increase as price falls, and everything under the sun neatly fits a power law. Or so the story goes...

Realization of High-temperature Superconductivity in Nano-carbon Materials and Its Application

DTIC Science & Technology

2015-07-13

hottest topics in condensed matter physics and also for application to zero- emission energy system. In particular, carbon-based superconductors have...ernission energy system. In particular, carbon-based superconductors have attracted significant attention for high transition temperature (T c). In...e-based superconductors have previously shown T c > 40K among various superconductors . In particular, carbon-base new SC exhibited T c < 20K in any

Weak localization of electromagnetic waves and opposition phenomena exhibited by high-albedo atmosphereless solar system objects.

PubMed

Mishchenko, Michael I; Rosenbush, Vera K; Kiselev, Nikolai N

2006-06-20

The totality of new and previous optical observations of a class of high-albedo solar system objects at small phase angles reveals a unique combination of extremely narrow brightness and polarization features centered at exactly the opposition. The specific morphological parameters of these features provide an almost unequivocal evidence that they are caused by the renowned effect of coherent backscattering.

Elastomer Compound Developed for High Wear Applications

NASA Technical Reports Server (NTRS)

Crawford, D.; Feuer, H.; Flanagan, D.; Rodriguez, G.; Teets, A.; Touchet, P.

1993-01-01

The U.S. Army is currently spending 300 million dollars per year replacing rubber track pads. An experimental rubber compound has been developed which exhibits 2 to 3 times greater service life than standard production pad compounds. To improve the service life of the tank track pads various aspects of rubber chemistry were explored including polymer, curing and reinforcing systems. Compounds that exhibited superior physical properties based on laboratory data were then fabricated into tank pads and field tested. This paper will discuss the compounding studies, laboratory data and field testing that led to the high wear elastomer compound.

Effects of high pressure processing on activity and structure of soluble acid invertase in mango pulp, crude extract, purified form and model systems.

PubMed

Li, Renjie; Wang, Yongtao; Ling, Jiangang; Liao, Xiaojun

2017-09-15

The effects of high pressure processing (HPP) on the activity of soluble acid invertase (SAI) in mango pulp, crude extract, purified SAI and purified SAI in model systems (pectin, bovine serum albumin (BSA), sugars and pH 3-7) were investigated. The activity of SAI in mango pulp was increased after HPP, and that in crude extract stayed unchanged. The activity of purified SAI was decreased after HPP at 45 and 50°C. Pectin exhibited a concentration-dependent protection for purified SAI against HPP at 50°C/600MPa for 30min. Pectin that had an esterification degree (DE) of 85% exhibited a greater protection than pectin that had a DE of 20-34%. BSA, acidic pH (3-6) and sucrose also exhibited protection for purified SAI against HPP. HPP at 50°C/600MPa for 30min disrupted the secondary structure and tertiary structure of purified SAI, but no aggregation of purified SAI was observed after HPP. Copyright © 2017 Elsevier Ltd. All rights reserved.

Fabrication of functional hollow microspheres constructed from MOF shells: Promising drug delivery systems with high loading capacity and targeted transport

PubMed Central

Gao, Xuechuan; Hai, Xiao; Baigude, Huricha; Guan, Weihua; Liu, Zhiliang

2016-01-01

An advanced multifunctional, hollow metal-organic framework (MOF) drug delivery system with a high drug loading level and targeted delivery was designed and fabricated for the first time and applied to inhibit tumour cell growth. This hollow MOF targeting drug delivery system was prepared via a simple post-synthetic surface modification procedure, starting from hollow ZIF-8 successfully obtained for the first time via a mild phase transformation under solvothermal conditions. As a result, the hollow ZIF-8 exhibits a higher loading capacity for the model anticancer drug 5-fluorouracil (5-FU). Subsequently, 5-FU-loaded ZIF-8 was encapsulated into polymer layers (FA-CHI-5-FAM) with three components: a chitosan (CHI) backbone, the imaging agent 5-carboxyfluorescein (5-FAM), and the targeting reagent folic acid (FA). Thus, an advanced drug delivery system, ZIF-8/5-FU@FA-CHI-5-FAM, was fabricated. A cell imaging assay demonstrated that ZIF-8/5-FU@FA-CHI-5-FAM could target and be taken up by MGC-803 cells. Furthermore, the as-prepared ZIF-8/5-FU@FA-CHI-5-FAM exhibited stronger cell growth inhibitory effects on MGC-803 cells because of the release of 5-FU, as confirmed by a cell viability assay. In addition, a drug release experiment in vitro indicated that ZIF-8/5-FU@FA-CHI-5-FAM exhibited high loading capacity (51%) and a sustained drug release behaviour. Therefore, ZIF-8/5-FU@FA-CHI-5-FAM could provide targeted drug transportation, imaging tracking and localized sustained release. PMID:27876876

Multifrequency Aperture-Synthesizing Microwave Radiometer System (MFASMR). Volume 1

NASA Technical Reports Server (NTRS)

Wiley, C. A.; Chang, M. U.

1981-01-01

Background material and a systems analysis of a multifrequency aperture - synthesizing microwave radiometer system is presented. It was found that the system does not exhibit high performance because much of the available thermal power is not used in the construction of the image and because the image that can be formed has a resolution of only ten lines. An analysis of image reconstruction is given. The system is compared with conventional aperture synthesis systems.

Thermoelectric Properties in the TiO2/SnO2 System

NASA Technical Reports Server (NTRS)

Dynys, F.; Sayir, A.; Sehirlioglu, A.; Berger, M.

2009-01-01

Nanotechnology has provided a new interest in thermoelectric technology. A thermodynamically driven process is one approach in achieving nanostructures in bulk materials. TiO2/SnO2 system exhibits a large spinodal region with exceptional stable phase separated microstructures up to 1400 C. Fabricated TiO2/SnO2 nanocomposites exhibit n-type behavior with Seebeck coefficients greater than -300 .V/K. Composites exhibit good thermal conductance in the range of 7 to 1 W/mK. Dopant additions have not achieved high electrical conductivity (<1000 S/m). Formation of oxygen deficient composites, TixSn1-xO2-y, can change the electrical conductivity by four orders of magnitude. Achieving higher thermoelectric ZT by oxygen deficiency is being explored. Seebeck coeffcient, thermal conductivity, electrical conductance and microstructure will be discussed in relation to composition and doping.

Coupled ultrasonication-milling synthesis of hierarchically porous carbon for high-performance supercapacitor.

PubMed

Yang, Dewei; Jing, Huijuan; Wang, Zhaowu; Li, Jiaheng; Hu, Mingxiang; Lv, Ruitao; Zhang, Rui; Chen, Deliang

2018-05-19

Activated carbon (AC) based supercapacitors exhibit intrinsic advantages in energy storage. Traditional two-step synthesis (carbonization and activation) of AC faces difficulties in precisely regulating its pore-size distribution and thoroughly removing residual impurities like silicon oxide. This paper reports a novel coupled ultrasonication-milling (CUM) process for the preparation of hierarchically porous carbon (HPC) using corn cobs as the carbon resource. The as-obtained HPC is of a large surface area (2288 m 2  g -1 ) with a high mesopore ratio of ∼44.6%. When tested in a three-electrode system, the HPC exhibits a high specific capacitance of 465 F g -1 at 0.5 Ag -1 , 2.7 times higher than that (170 F g -1 ) of the commercial AC (YP-50F). In the two-electrode test system, the HPC device exhibits a specific capacitance of 135 F g -1 at 1 A g -1 , twice higher than that (68 F g -1 ) of YP-50F. The above excellent energy-storage properties are resulted from the CUM process which efficiently removes the impurities and modulates the mesopore/micropore structures of the AC samples derived from the agricultural resides of corn cobs. The CUM process is an efficient method to prepare high-performance biomass-derived AC materials. Copyright © 2018 Elsevier Inc. All rights reserved.

High power and high energy electrodes using carbon nanotubes

DOEpatents

Martini, Fabrizio; Brambilla, Nicolo Michele; Signorelli, Riccardo

2015-04-07

An electrode useful in an energy storage system, such as a capacitor, includes an electrode that includes at least one to a plurality of layers of compressed carbon nanotube aggregate. Methods of fabrication are provided. The resulting electrode exhibits superior electrical performance in terms of gravimetric and volumetric power density.

A new transgenic rice line exhibiting enhanced ferric iron reduction and phytosiderophore production confers tolerance to low iron availability in calcareous soil.

PubMed

Masuda, Hiroshi; Shimochi, Erika; Hamada, Tatsuro; Senoura, Takeshi; Kobayashi, Takanori; Aung, May Sann; Ishimaru, Yasuhiro; Ogo, Yuko; Nakanishi, Hiromi; Nishizawa, Naoko K

2017-01-01

Iron (Fe) deficiency is a critical agricultural problem, especially in calcareous soil, which is distributed worldwide. Rice plants take up Fe(II) from soil through a OsIRT1 transporter (Strategy I-related system) and also take up Fe(III) via a phytosiderophore-based system (Strategy II system). However, rice plants are susceptible to low-Fe conditions because they have low Fe(III) reduction activity and low-level phytosiderophore secretion. Previously, we produced transgenic rice plants expressing a mutationally reconstructed yeast ferric chelate reductase, refre1/372, under the control of the OsIRT1 promoter. This transgenic rice line exhibited higher Fe(III) chelate reductase activity and tolerance to Fe deficiency. In addition, we produced transgenic rice overexpressing the Fe deficiency-inducible transcription factor, OsIRO2, which regulates the expression of various genes involved in the strategy II Fe(III) uptake system, including OsNAS1, OsNAAT1, OsDMAS1, OsYSL15, and TOM1. This transgenic rice exhibited improved phytosiderophore secretion ability and tolerance to Fe deficiency. In the present research, transgenic rice plants that possess both the OsIRT1 promoter-refre1/372 and the 35S promoter-OsIRO2 (RI lines) were produced to enhance both Strategy I Fe(II) reductase ability and Strategy II phytosiderophore productivity. RI lines exhibited enhanced tolerance to Fe-deficient conditions at the early and middle-late stages of growth in calcareous soil, compared to both the non-transgenic line and lines harboring either OsIRT1 promoter-refre1/372 or 35S promoter-OsIRO2 alone. RI lines also exhibited a 9-fold higher yield than the non-transgenic line. Moreover, we successfully produced Fe-deficiency-tolerant Tachisugata rice, which is a high-biomass variety used as fodder. Collectively, our results demonstrate that combined enhancement of two Fe uptake systems in rice is highly effective in conferring tolerance to low Fe availability in calcareous soil.

A supersaturating delivery system of silibinin exhibiting high payload achieved by amorphous nano-complexation with chitosan.

PubMed

Nguyen, Minh-Hiep; Yu, Hong; Dong, Bingxue; Hadinoto, Kunn

2016-06-30

The therapeutic potentials of silibinin - a phytochemical isolated from milk thistle plants - have not been fully realized due to its poor oral bioavailability caused by the low aqueous solubility. Existing solubility enhancement strategies of silibinin by nanonization were limited by their low payload. Herein we developed a supersaturating delivery system of silibinin exhibiting a high payload (≈76%) in the form of amorphous silibinin-chitosan nanoparticle complex (or silibinin nanoplex in short) prepared by self-assembly drug-polysaccharide complexation. The effects of (1) pH and (2) charge ratio of chitosan to silibinin on the nanoplex's physical characteristics (i.e. size, zeta potential, and payload) and preparation efficiency (i.e. silibinin utilization, overall yield) were investigated. The formation of nanoplex (≈240nm) was feasible only in a narrow pH range (5.1-5.8) and favored charge ratio below unity. At the optimal condition (pH 5.8 and charge ratio of 0.30), the nanoplex preparation exhibited 87% silibinin utilization rate and 63% yield signifying its high efficiency. The amorphous state and colloidal stabilities of the nanoplex during storage, and prolonged supersaturation generation (3h) at more than 10× of the saturation solubility were successfully demonstrated. Copyright © 2016 Elsevier B.V. All rights reserved.

34th Annual Gun and Ammunitions Symposium and Exhibition held in Monterey, CA on 26-29 April 1999

DTIC Science & Technology

1999-04-01

Allan Buckley, Oerlikon Contraves ൫/50MM HETF (High Explosive Time Fuze) Ammunition" by Mr. Stephen Kerk and Mr. Peter Moore,* Diehl Stifung & Co...Technologies, Inc. "OICW Fire Control System" by Mr. Grant Moule*; Ms. Susan Franciscus*, Contraves Brashear Systems L.P. "Air Bursting Systems" by Mr. John

Aggregation-Induced Emission (AIE) Fluorophore Exhibits a Highly Ratiometric Fluorescent Response to Zn2+ in vitro and in Human Liver Cancer Cells.

PubMed

Mehdi, Hassan; Gong, Weitao; Guo, Huimin; Watkinson, Michael; Ma, Hua; Wajahat, Ali; Ning, Guiling

2017-09-21

Two novel organic fluorophores, containing bis-naphthylamide and quinoline motifs, have been designed and synthesized. One of the fluorophores contains an isobutylene unit and exhibits a significant aggregation-induced emission (AIE) and a remarkable highly selective ratiometric fluorescence response towards Zn 2+ in solution as well as in human liver cancer cells. The AIE behavior of this fluorophore was fully verified by fluorescence and UV/Vis spectroscopy, quantum yield calculations, and single-crystal X-ray diffraction, which revealed an intricate crystal packing system. Conversely, a fluorophore that lacks the isobutylene moiety did not exhibit any significant fluorescent properties as a result of its more flexible molecular structure that presumably allows free intramolecular rotational processes to occur. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

An all-organic composite actuator material with a high dielectric constant.

PubMed

Zhang, Q M; Li, Hengfeng; Poh, Martin; Xia, Feng; Cheng, Z-Y; Xu, Haisheng; Huang, Cheng

2002-09-19

Electroactive polymers (EAPs) can behave as actuators, changing their shape in response to electrical stimulation. EAPs that are controlled by external electric fields--referred to here as field-type EAPs--include ferroelectric polymers, electrostrictive polymers, dielectric elastomers and liquid crystal polymers. Field-type EAPs can exhibit fast response speeds, low hysteresis and strain levels far above those of traditional piezoelectric materials, with elastic energy densities even higher than those of piezoceramics. However, these polymers also require a high field (>70 V micro m(-1)) to generate such high elastic energy densities (>0.1 J cm(-3); refs 4, 5, 9, 10). Here we report a new class of all-organic field-type EAP composites, which can exhibit high elastic energy densities induced by an electric field of only 13 V micro m(-1). The composites are fabricated from an organic filler material possessing very high dielectric constant dispersed in an electrostrictive polymer matrix. The composites can exhibit high net dielectric constants while retaining the flexibility of the matrix. These all-organic actuators could find applications as artificial muscles, 'smart skins' for drag reduction, and in microfluidic systems for drug delivery.

Analysis of genetic admixture in Uyghur using the 26 Y-STR loci system

PubMed Central

Bian, Yingnan; Zhang, Suhua; Zhou, Wei; Zhao, Qi; Siqintuya; Zhu, Ruxin; Wang, Zheng; Gao, Yuzhen; Hong, Jie; Lu, Daru; Li, Chengtao

2016-01-01

The Uyghur population has experienced extensive interaction with European and Eastern Asian populations historically. A set of high-resolution genetic markers could be useful to infer the genetic relationships between the Uyghur population and European and Asian populations. In this study we typed 100 unrelated Uyghur males living in southern Xinjiang at 26 Y-STR loci. Using the high-resolution 26 Y-STR loci system, we investigated genetic and phylogenetic relationship between the Uyghur population and 23 reference European or Asian populations. We found that the Uyghur population exhibited a genetic admixture of Eastern Asian and European populations, and had a slightly closer relationship with the selected European populations than the Eastern Asian populations. We also demonstrated that the 26 Y-STR loci system was potentially useful in forensic sciences because it has a large power of discrimination and rarely exhibits common haplotypes. However, ancestry inference of Uyghur samples could be challenging due to the admixed nature of the population. PMID:26842947

Analysis of genetic admixture in Uyghur using the 26 Y-STR loci system.

PubMed

Bian, Yingnan; Zhang, Suhua; Zhou, Wei; Zhao, Qi; Siqintuya; Zhu, Ruxin; Wang, Zheng; Gao, Yuzhen; Hong, Jie; Lu, Daru; Li, Chengtao

2016-02-04

The Uyghur population has experienced extensive interaction with European and Eastern Asian populations historically. A set of high-resolution genetic markers could be useful to infer the genetic relationships between the Uyghur population and European and Asian populations. In this study we typed 100 unrelated Uyghur males living in southern Xinjiang at 26 Y-STR loci. Using the high-resolution 26 Y-STR loci system, we investigated genetic and phylogenetic relationship between the Uyghur population and 23 reference European or Asian populations. We found that the Uyghur population exhibited a genetic admixture of Eastern Asian and European populations, and had a slightly closer relationship with the selected European populations than the Eastern Asian populations. We also demonstrated that the 26 Y-STR loci system was potentially useful in forensic sciences because it has a large power of discrimination and rarely exhibits common haplotypes. However, ancestry inference of Uyghur samples could be challenging due to the admixed nature of the population.

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

Jiang, Daqiang, E-mail: dq80jiang@126.com; Cui, Lishan; Jiang, Jiang

Graphical abstract: - Highlights: • In situ NiTi/Nb(Ti) composites were fabricated. • The transformation temperature was affected by the mixing Ti:Ni atomic ratios. • The NiTi component became micron-scale lamella after forging and rolling. • The composite exhibited high strength and high damping capacity. - Abstract: This paper reports on the creation of a series of in situ NiTi/Nb(Ti) composites with controllable transformation temperatures based on the pseudo-binary hypereutectic transformation of NiTi–Nb system. The composite constituent morphology was controlled by forging and rolling. It is found that the thickness of the NiTi lamella in the composite reached micron level aftermore » the hot-forging and cold-rolling. The NiTi/Nb(Ti) composite exhibited high damping capacity as well as high yield strength.« less

Dynamic memory of a single voltage-gated potassium ion channel: A stochastic nonequilibrium thermodynamic analysis

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

Banerjee, Kinshuk, E-mail: kbpchem@gmail.com

2015-05-14

In this work, we have studied the stochastic response of a single voltage-gated potassium ion channel to a periodic external voltage that keeps the system out-of-equilibrium. The system exhibits memory, resulting from time-dependent driving, that is reflected in terms of dynamic hysteresis in the current-voltage characteristics. The hysteresis loop area has a maximum at some intermediate voltage frequency and disappears in the limits of low and high frequencies. However, the (average) dissipation at long-time limit increases and finally goes to saturation with rising frequency. This raises the question: how diminishing hysteresis can be associated with growing dissipation? To answer this,more » we have studied the nonequilibrium thermodynamics of the system and analyzed different thermodynamic functions which also exhibit hysteresis. Interestingly, by applying a temporal symmetry analysis in the high-frequency limit, we have analytically shown that hysteresis in some of the periodic responses of the system does not vanish. On the contrary, the rates of free energy and internal energy change of the system as well as the rate of dissipative work done on the system show growing hysteresis with frequency. Hence, although the current-voltage hysteresis disappears in the high-frequency limit, the memory of the ion channel is manifested through its specific nonequilibrium thermodynamic responses.« less

Around Marshall

NASA Image and Video Library

2002-06-01

This photograph shows Justin Varnadore, son of a Marshall TV employee, at the controls of one of the many displays within the Starship 2040 exhibit on display at Joe Davis Stadium in Huntsville, Alabama. Developed by the Space Transportation Directorate at Marshall Space Flight Center (MSFC), the Starship 2040 exhibit is housed in a 48-ft (14.6-m) tractor and trailer rig, permitting it to travel around the Nation, demonstrating NASA's vision of what commercial spaceflight might be like 40 years from now. All the irnovations suggested aboard the exhibit (automated vehicle health monitoring systems, high-energy propulsion drive, navigational aids, and emergency and safety systems) are based on concepts and technologies now being studied at NASA Centers and partner institutions around the Nation. NASA is the Nation's premier agency for development of the space transportation system, including future-generation reusable launch vehicles. Such systems, the keys to a "real" Starship 2040, require revolutionary advances in critical aerospace technologies, from thermal, magnetic, chemical, and propellantless propulsion systems to new energy sources such as space solar power or antimatter propulsion. These and other advances are now being studied, developed, and tested at NASA field centers and partner institutions all over the Nation.

Influence of volcanic history on groundwater patterns on the west slope of the Oregon High Cascades.

Treesearch

A. Jefferson; G. Grant; T. Rose

2006-01-01

Spring systems on the west slope of the Oregon High Cascades exhibit complex relationships among modern topography, lava flow geometries, and groundwater flow patterns. Seven cold springs were continuously monitored for discharge and temperature in the 2004 water year, and they were periodically sampled for ?18O, ?D, tritium, and dissolved noble gases. Anomalously high...

Facile electrodeposition of reduced graphene oxide hydrogels for high-performance supercapacitors

NASA Astrophysics Data System (ADS)

Pham, Viet Hung; Gebre, Tesfaye; Dickerson, James H.

2015-03-01

We report both a facile, scalable method to prepare reduced graphene oxide hydrogels through the electrodeposition of graphene oxide and its use as an electrode for high-performance supercapacitors. Such systems exhibited specific capacitances of 147 and 223 F g-1 at a current density of 10 A g-1 when using H2SO4 and H2SO4 + hydroquinone redox electrolytes, respectively.We report both a facile, scalable method to prepare reduced graphene oxide hydrogels through the electrodeposition of graphene oxide and its use as an electrode for high-performance supercapacitors. Such systems exhibited specific capacitances of 147 and 223 F g-1 at a current density of 10 A g-1 when using H2SO4 and H2SO4 + hydroquinone redox electrolytes, respectively. Electronic supplementary information (ESI) available: GO synthesis, characterization, fabrication of ERGO supercapacitor and electrochemical measurement, elemental composition, TGA and XRD of GO and ERGO. See DOI: 10.1039/c4nr07508k

Generation of efficient 33 GHz optical combs using cascaded stimulated Brillouin scattering effects in optical fiber

NASA Astrophysics Data System (ADS)

Al-Mansoori, M. H.; Al-Sheriyani, A.; Al-Nassri, S.; Hasoon, F. N.

2017-06-01

In this paper, we demonstrate a multi-wavelength Brillouin-erbium fiber laser (BEFL) with ~33 GHz frequency spacing using cascaded stimulated Brillouin scattering effects in optical fiber. The proposed laser structure exhibits a stable output channel with a tuning range of 19 nm, from 1549 nm to 1568 nm. The number of stable output channels produced is six channels with a triple-Brillouin frequency spacing. The output channels exhibit high output power and high optical signal-to-noise ratios (OSNRs). The laser structure has the potential to be used as a multi-wavelength source for optical communication systems.

Many-body localization beyond eigenstates in all dimensions

NASA Astrophysics Data System (ADS)

Chandran, A.; Pal, A.; Laumann, C. R.; Scardicchio, A.

2016-10-01

Isolated quantum systems with quenched randomness exhibit many-body localization (MBL), wherein they do not reach local thermal equilibrium even when highly excited above their ground states. It is widely believed that individual eigenstates capture this breakdown of thermalization at finite size. We show that this belief is false in general and that a MBL system can exhibit the eigenstate properties of a thermalizing system. We propose that localized approximately conserved operators (l*-bits) underlie localization in such systems. In dimensions d >1 , we further argue that the existing MBL phenomenology is unstable to boundary effects and gives way to l*-bits . Physical consequences of l*-bits include the possibility of an eigenstate phase transition within the MBL phase unrelated to the dynamical transition in d =1 and thermal eigenstates at all parameters in d >1 . Near-term experiments in ultracold atomic systems and numerics can probe the dynamics generated by boundary layers and emergence of l*-bits .

State of Oklahoma v. Tracy Smith. 1999-2000 Oklahoma High School Mock Trial Program.

ERIC Educational Resources Information Center

Stucky, Melanie; Eberle, April; Cale, Stephen

This mock trial curriculum is intended to help high school students learn about the law and the legal system. The curriculum is divided into the following sections: Statement of the Case, Stipulations, Legal Authorities, Witness Statements/Narrative Report (Prosecution Witnesses; Defense Witnesses), and Exhibits (Statement of Miranda Rights; Front…

Developmental Assets: Profile of Youth in a Juvenile Justice Facility

ERIC Educational Resources Information Center

Chew, Weslee; Osseck, Jenna; Raygor, Desiree; Eldridge-Houser, Jennifer; Cox, Carol

2010-01-01

Background: Possessing high numbers of developmental assets greatly reduces the likelihood of a young person engaging in health-risk behaviors. Since youth in the juvenile justice system seem to exhibit many high-risk behaviors, the purpose of this study was to assess the presence of external, internal, and social context areas of developmental…

Multichannel System Based on a High Sensitivity Superconductive Sensor for Magnetoencephalography

PubMed Central

Rombetto, Sara; Granata, Carmine; Vettoliere, Antonio; Russo, Maurizio

2014-01-01

We developed a multichannel system based on superconducting quantum interference devices (SQUIDs) for magnetoencephalography measurements. Our system consists of 163 fully-integrated SQUID magnetometers, 154 channels and 9 references, and all of the operations are performed inside a magnetically-shielded room. The system exhibits a magnetic field noise spectral density of approximatively 5 fT/Hz1/2. The presented magnetoencephalography is the first system working in a clinical environment in Italy. PMID:25006995

Systemic regulation of leaf anatomical structure, photosynthetic performance, and high-light tolerance in sorghum.

PubMed

Jiang, Chuang-Dao; Wang, Xin; Gao, Hui-Yuan; Shi, Lei; Chow, Wah Soon

2011-03-01

Leaf anatomy of C3 plants is mainly regulated by a systemic irradiance signal. Since the anatomical features of C4 plants are different from that of C3 plants, we investigated whether the systemic irradiance signal regulates leaf anatomical structure and photosynthetic performance in sorghum (Sorghum bicolor), a C4 plant. Compared with growth under ambient conditions (A), no significant changes in anatomical structure were observed in newly developed leaves by shading young leaves alone (YS). Shading mature leaves (MS) or whole plants (S), on the other hand, caused shade-leaf anatomy in newly developed leaves. By contrast, chloroplast ultrastructure in developing leaves depended only on their local light conditions. Functionally, shading young leaves alone had little effect on their net photosynthetic capacity and stomatal conductance, but shading mature leaves or whole plants significantly decreased these two parameters in newly developed leaves. Specifically, the net photosynthetic rate in newly developed leaves exhibited a positive linear correlation with that of mature leaves, as did stomatal conductance. In MS and S treatments, newly developed leaves exhibited severe photoinhibition under high light. By contrast, newly developed leaves in A and YS treatments were more resistant to high light relative to those in MS- and S-treated seedlings. We suggest that (1) leaf anatomical structure, photosynthetic capacity, and high-light tolerance in newly developed sorghum leaves were regulated by a systemic irradiance signal from mature leaves; and (2) chloroplast ultrastructure only weakly influenced the development of photosynthetic capacity and high-light tolerance. The potential significance of the regulation by a systemic irradiance signal is discussed.

High Temperature Transfer Molding Resins

NASA Technical Reports Server (NTRS)

Connell, John W. (Inventor); Smith, Joseph G., Jr. (Inventor); Hergenrother, Paul M. (Inventor)

2000-01-01

High temperature resins containing phenylethynyl groups that are processable by transfer molding have been prepared. These phenylethynyl containing oligomers were prepared from aromatic diamines containing phenylethynyl groups and various ratios of phthalic anhydride and 4-phenylethynlphthalic anhydride in glacial acetic acid to form a mixture of imide compounds in one step. This synthetic approach is advantageous since the products are a mixture of compounds and consequently exhibit a relatively low melting temperature. In addition, these materials exhibit low melt viscosities which are stable for several hours at 210-275 C, and since the thermal reaction of the phenylethynyl group does not occur to any appreciable extent at temperatures below 300 C, these materials have a broad processing window. Upon thermal cure at approximately 300-350 C, the phenylethynyl groups react to provide a crosslinked resin system. These new materials exhibit excellent properties and are potentially useful as adhesives, coatings, films, moldings and composite matrices.

Intelligent Systems and Its Applications in Robotics

NASA Astrophysics Data System (ADS)

Kaynak, Okyay

The last decade of the last millennium is characterized by what might be called the intelligent systems revolution, as a result of which, it is now possible to have man made systems that exhibit ability to reason, learn from experience and make rational decisions without human intervention. Prof. Zadeh has coined the word MIQ (machine intelligence quotient) to describe a measure of intelligence of man-made systems. In this perspective, an intelligent system can be defined as a system that has a high MIQ.

Solid-Body Fuse Developed for High- Voltage Space Power Missions

NASA Technical Reports Server (NTRS)

Dolce, James L.; Baez, Anastacio N.

2001-01-01

AEM Incorporated has completed the development, under a NASA Glenn Research Center contract, of a solid-body fuse for high-voltage power systems of satellites and spacecraft systems. High-reliability fuses presently defined by MIL-PRF-23419 do not meet the increased voltage and amperage requirements for the next generation of spacecraft. Solid-body fuses exhibit electrical and mechanical attributes that enable these fuses to perform reliably in the vacuum and high-vibration and -shock environments typically present in spacecraft applications. The construction and screening techniques for solid-body fuses described by MIL-PRF-23419/12 offer an excellent roadmap for the development of high-voltage solid-body fuses.

Enhancing Performance of Large-Area Organic Solar Cells with Thick Film via Ternary Strategy.

PubMed

Zhang, Jianqi; Zhao, Yifan; Fang, Jin; Yuan, Liu; Xia, Benzheng; Wang, Guodong; Wang, Zaiyu; Zhang, Yajie; Ma, Wei; Yan, Wei; Su, Wenming; Wei, Zhixiang

2017-06-01

Large-scale fabrication of organic solar cells requires an active layer with high thickness tolerability and the use of environment-friendly solvents. Thick films with high-performance can be achieved via a ternary strategy studied herein. The ternary system consists of one polymer donor, one small molecule donor, and one fullerene acceptor. The small molecule enhances the crystallinity and face-on orientation of the active layer, leading to improved thickness tolerability compared with that of a polymer-fullerene binary system. An active layer with 270 nm thickness exhibits an average power conversion efficiency (PCE) of 10.78%, while the PCE is less than 8% with such thick film for binary system. Furthermore, large-area devices are successfully fabricated using polyethylene terephthalate (PET)/Silver gride or indium tin oxide (ITO)-based transparent flexible substrates. The product shows a high PCE of 8.28% with an area of 1.25 cm 2 for a single cell and 5.18% for a 20 cm 2 module. This study demonstrates that ternary organic solar cells exhibit great potential for large-scale fabrication and future applications. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Macrophyte Community Response to Nitrogen Loading and ...

EPA Pesticide Factsheets

Empirical determination of nutrient loading thresholds that negatively impact seagrass communities have been elusive due to the multitude of factors involved. Using a mesocosm system that simulated Pacific Northwest estuaries, we evaluated macrophyte metrics across gradients of NO3 loading (0, 1.5, 3 and 6x ambient) and temperature (10 and 20 °C). Macroalgal growth, biomass, and C:N responded positively to increased NO3 load and floating algal mats developed at 20 ºC. Zostera japonica metrics, including C:N, responded more to temperature than to NO3 loading. Z. marina biomass exhibited a negative temperature effect and in some cases a negative NO3 effect, while growth rate increased with temperature. Shoot survival decreased at 20 ºC but was not influenced by NO3 loading. Wasting disease index exhibited a significant temperature by NO3 interaction consistent with increased disease susceptibility. Community shifts observed were consistent with the nutrient loading hypothesis at 20 ºC, but there was no evidence of other eutrophication symptoms due to the short residence time. The Nutrient Pollution Index tracked the NO3 gradient at 10 ºC but exhibited no response at 20 ºC. We suggest that systems characterized by cool temperatures, high NO3 loads, and short residence time may be resilient to many symptoms of eutrophication. Estuarine systems characterized by cool temperatures, high nutrient loads and rapid flushing may be resilient to some symptoms

In situ high temperature X-Ray diffraction study of the phase equilibria in the UO2-PuO2-Pu2O3 system

NASA Astrophysics Data System (ADS)

Belin, Renaud C.; Strach, Michal; Truphémus, Thibaut; Guéneau, Christine; Richaud, Jean-Christophe; Rogez, Jacques

2015-10-01

The region of the U-Pu-O phase diagram delimited by the compounds UO2-PuO2-Pu2O3 is known to exhibit a miscibility gap at low temperature. Consequently, MOX fuels with a composition entering this region could decompose into two fluorite phases and thus exhibit chemical heterogeneities. The experimental data on this domain found in the literature are scarce and usually provided using DTA that is not suitable for the investigation of such decomposition phenomena. In the present work, new experimental data, i.e. crystallographic phases, lattice parameters, phase fractions and temperature of phase separation, were measured in the composition range 0.14 < Pu/(U + Pu) < 0.62 and 1.85 < O/(U + Pu) < 2 from 298 to 1750 K using a novel in situ high temperature X-ray diffraction apparatus. A very good agreement is found between the temperature of phase separation determined from our results and using the thermodynamic model of the U-Pu-O system based on the CALPHAD method. Also, the combined use of thermodynamic calculations and XRD results refinement proved helpful in the determination of the O/M ratio of the samples during cooling. The methodology used in the current work might be useful to investigate other oxides systems exhibiting a miscibility gap.

Gold nanoparticle incorporated polymer/bioactive glass composite for controlled drug delivery application.

PubMed

Jayalekshmi, A C; Sharma, Chandra P

2015-02-01

The present study discusses the development of a biodegradable polymer encapsulated-nanogold incorporated-bioactive glass composite (AuPBG) by a low-temperature method. The composite was analyzed by atomic force microscopy (AFM), X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, thermogravimetry (TG), fluorescence and dissolution analysis. The composite exhibited aggregation behaviour in solid and solution states and exhibited negative zeta potential (-13.3 ± 1.4 mV). The composite exhibited fast degradation starting from the 5(th) day onwards in phosphate buffered saline (PBS) for a period of 14 days. The composite showed fluorescence quenching effect at pH 7 and the fluorescence recovered at pH 5. The composite has been found to be suitable for the release of doxorubicin at high rates at acidic pH (∼ 5) which is the intracellular pH of tumour cells. The drug loading ratio is also high and it exhibited a controlled release for a period of 8 days in PBS. The system serves as a promising material for targeted drug delivery applications. Copyright © 2014 Elsevier B.V. All rights reserved.

Functional dissection of hematopoietic stem cell populations with a stemness-monitoring system based on NS-GFP transgene expression.

PubMed

Ali, Mohamed A E; Fuse, Kyoko; Tadokoro, Yuko; Hoshii, Takayuki; Ueno, Masaya; Kobayashi, Masahiko; Nomura, Naho; Vu, Ha Thi; Peng, Hui; Hegazy, Ahmed M; Masuko, Masayoshi; Sone, Hirohito; Arai, Fumio; Tajima, Atsushi; Hirao, Atsushi

2017-09-12

Hematopoietic stem cells (HSCs) in a steady state can be efficiently purified by selecting for a combination of several cell surface markers; however, such markers do not consistently reflect HSC activity. In this study, we successfully enriched HSCs with a unique stemness-monitoring system using a transgenic mouse in which green florescence protein (GFP) is driven by the promoter/enhancer region of the nucleostemin (NS) gene. We found that the phenotypically defined long-term (LT)-HSC population exhibited the highest level of NS-GFP intensity, whereas NS-GFP intensity was strongly downregulated during differentiation in vitro and in vivo. Within the LT-HSC population, NS-GFP high cells exhibited significantly higher repopulating capacity than NS-GFP low cells. Gene expression analysis revealed that nine genes, including Vwf and Cdkn1c (p57), are highly expressed in NS-GFP high cells and may represent a signature of HSCs, i.e., a stemness signature. When LT-HSCs suffered from remarkable stress, such as transplantation or irradiation, NS-GFP intensity was downregulated. Finally, we found that high levels of NS-GFP identified HSC-like cells even among CD34 + cells, which have been considered progenitor cells without long-term reconstitution ability. Thus, high NS-GFP expression represents stem cell characteristics in hematopoietic cells, making this system useful for identifying previously uncharacterized HSCs.

Homogeneous (Cu, Ni)6Sn5 intermetallic compound joints rapidly formed in asymmetrical Ni/Sn/Cu system using ultrasound-induced transient liquid phase soldering process.

PubMed

Li, Z L; Dong, H J; Song, X G; Zhao, H Y; Tian, H; Liu, J H; Feng, J C; Yan, J C

2018-04-01

Homogeneous (Cu, Ni) 6 Sn 5 intermetallic compound (IMC) joints were rapidly formed in asymmetrical Ni/Sn/Cu system by an ultrasound-induced transient liquid phase (TLP) soldering process. In the traditional TLP soldering process, the intermetallic joints formed in Ni/Sn/Cu system consisted of major (Cu, Ni) 6 Sn 5 and minor Cu 3 Sn IMCs, and the grain morphology of (Cu, Ni) 6 Sn 5 IMCs subsequently exhibited fine rounded, needlelike and coarse rounded shapes from the Ni side to the Cu side, which was highly in accordance with the Ni concentration gradient across the joints. However, in the ultrasound-induced TLP soldering process, the intermetallic joints formed in Ni/Sn/Cu system only consisted of the (Cu, Ni) 6 Sn 5 IMCs which exhibited an uniform grain morphology of rounded shape with a remarkably narrowed Ni concentration gradient. The ultrasound-induced homogeneous intermetallic joints exhibited higher shear strength (61.6 MPa) than the traditional heterogeneous intermetallic joints (49.8 MPa). Copyright © 2017 Elsevier B.V. All rights reserved.

Highly efficient exciplex organic light-emitting diodes incorporating a heptazine derivative as an electron acceptor.

PubMed

Li, Jie; Nomura, Hiroko; Miyazaki, Hiroshi; Adachi, Chihaya

2014-06-11

Highly efficient exciplex systems incorporating a heptazine derivative () as an electron acceptor and 1,3-di(9H-carbazol-9-yl)benzene () as an electron donor are developed. An organic light-emitting diode containing 8 wt% : as an emitting layer exhibits a maximum external quantum efficiency of 11.3%.

Liquid monobenzoxazine based resin system

DOEpatents

Tietze, Roger; Nguyen, Yen-Loan; Bryant, Mark

2014-10-07

The present invention provides a liquid resin system including a liquid monobenzoxazine monomer and a non-glycidyl epoxy compound, wherein the weight ratio of the monobenzoxazine monomer to the non-glycidyl epoxy compound is in a range of about 25:75 to about 60:40. The liquid resin system exhibits a low viscosity and exceptional stability over an extended period of time making its use in a variety of composite manufacturing methods highly advantageous.

Can mixed star-plus-wormhole systems mimic black holes?

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

Dzhunushaliev, Vladimir; Folomeev, Vladimir; Kleihaus, Burkhard

We consider mixed strongly gravitating configurations consisting of a wormhole threaded by two types of ordinary matter. For such systems, the possibility of obtaining static spherically symmetric solutions describing compact massive central objects enclosed by high-redshift surfaces (black-hole-like configurations) is studied. Using the standard thin accretion disk model, we exhibit potentially observable differences allowing to distinguish the mixed systems from ordinary black holes with the same masses.

Cooperative CO2 Absorption Isotherms from a Bifunctional Guanidine and Bifunctional Alcohol.

PubMed

Steinhardt, Rachel; Hiew, Stanley C; Mohapatra, Hemakesh; Nguyen, Du; Oh, Zachary; Truong, Richard; Esser-Kahn, Aaron

2017-12-27

Designing new liquids for CO 2 absorption is a challenge in CO 2 removal. Here, achieving low regeneration energies while keeping high selectivity and large capacity are current challenges. Recent cooperative metal-organic frameworks have shown the potential to address many of these challenges. However, many absorbent systems and designs rely on liquid capture agents. We present herein a liquid absorption system which exhibits cooperative CO 2 absorption isotherms. Upon introduction, CO 2 uptake is initially suppressed, followed by an abrupt increase in absorption. The liquid consists of a bifunctional guanidine and bifunctional alcohol, which, when dissolved in bis(2-methoxyethyl) ether, forms a secondary viscous phase within seconds in response to increases in CO 2 . The precipitation of this second viscous phase drives CO 2 absorption from the gas phase. The isotherm of the bifunctional system differs starkly from the analogous monofunctional system, which exhibits limited CO 2 uptake across the same pressure range. In our system, CO 2 absorption is strongly solvent dependent. In DMSO, both systems exhibit hyperbolic isotherms and no precipitation occurs. Subsequent 1 H NMR experiments confirmed the formation of distinct alkylcarbonate species having either one or two molecules of CO 2 bound. The solvent and structure relationships derived from these results can be used to tailor new liquid absorption systems to the conditions of a given CO 2 separation process.

Novel disturbance-observer-based control for systems with high-order mismatched disturbances

NASA Astrophysics Data System (ADS)

Fang, Xing; Liu, Fei; Wang, Zhiguo; Dong, Na

2018-01-01

A novel disturbance-observer-based control method is investigated to attenuate the high-order mismatched disturbances. First, a finite-time disturbance observer (FTDO) is proposed to estimate the disturbances as well as the derivatives. By incorporating the outputs of FTDO, the original system is then reconstructed, where the mismatched disturbances are transformed to the matched ones that are compensated by feed-forward algorithm. Moreover, a feedback control law is developed to achieve the stability and tracking performance requirements for the systems. Finally, the proposed composite control method is applied to an unmanned helicopter system. The simulation results demonstrate that the proposed control method exhibits excellent control performance in the presence of high-order matched and mismatched disturbances.

Improved All-Terrain Suspension System

NASA Technical Reports Server (NTRS)

Bickler, Donald B.

1994-01-01

Redesigned suspension system for all-terrain vehicle exhibits enhanced ability to negotiate sand and rocks. Improved six-wheel suspension system includes only two links on each side. Bogie tends to pull rear wheels with it as it climbs. Designed for rover vehicle for exploration of Mars, also has potential application in off-road vehicles, military scout vehicles, robotic emergency vehicles, and toys. Predecessors of suspension system described in "Articulated Suspension Without Springs" (NPO-17354), "Four-Wheel Vehicle Suspension System" (NPO-17407), and "High-Clearance Six-Wheel Suspension" (NPO-17821).

Correlations of Life Form, Pollination Mode and Sexual System in Aquatic Angiosperms

PubMed Central

Du, Zhi-Yuan; Wang, Qing-Feng

2014-01-01

Aquatic plants are phylogenetically well dispersed across the angiosperms. Reproductive and other life-history traits of aquatic angiosperms are closely associated with specific growth forms. Hydrophilous pollination exhibits notable examples of convergent evolution in angiosperm reproductive structures, and hydrophiles exhibit great diversity in sexual system. In this study, we reconstructed ancestral characters of aquatic lineages based on the phylogeny of aquatic angiosperms. Our aim is to find the correlations of life form, pollination mode and sexual system in aquatic angiosperms. Hydrophily is the adaptive evolution of completely submersed angiosperms to aquatic habitats. Hydroautogamy and maleflower-ephydrophily are the transitional stages from anemophily and entomophily to hydrophily. True hydrophily occurs in 18 submersed angiosperm genera, which is associated with an unusually high incidence of unisexual flowers. All marine angiosperms are submersed, hydrophilous species. This study would help us understand the evolution of hydrophilous pollination and its correlations with life form and sexual system. PMID:25525810

High-energy non-rechargeable batteries and their applications

NASA Astrophysics Data System (ADS)

Higgins, Robert; Kruger, Ken

1990-04-01

Many of the more recently developed high energy battery systems employ Li anodes, which are capable of energy densities of 700 W h/kg and shelf power-losses of less than 3 percent/yr. It has been noted, however, that some Li-based systems exhibit 'voltage sag' during storage and pose some safety problems in cases of inadvertent abuse. The two highest energy-output yielding of the current Li systems, namely Li/CF(x) spiral cells and Li/thionyl chloride liquid cathode cells, are presented and compared with a Zn/AgO electrochemical (aqueous) battery system which, although of older design, is still capable of substantial energy densities.

CA resist with high sensitivity and sub-100-nm resolution for advanced mask and device making

NASA Astrophysics Data System (ADS)

Kwong, Ranee W.; Huang, Wu-Song; Hartley, John G.; Moreau, Wayne M.; Robinson, Christopher F.; Angelopoulos, Marie; Magg, Christopher; Lawliss, Mark

2000-07-01

Recently, there is significant interest in using CA resists for electron beam (E-Beam) applications including mask making, direct write, and projection printing. CA resists provide superior lithographic performance in comparison to traditional non CA E-beam resists in particular high contrast, resolution, and sensitivity. However, most of the commercially available CA resists have the concern of airborne base contaminants and sensitivity to PAB and/or PEB temperatures. In this presentation, we will discuss a new improved ketal resist system referred to as KRS-XE which exhibits excellent lithography, is robust toward airborne base, compatible with 0.263 N TMAH aqueous developer and exhibits a large PAB/PEB latitude. With the combination of a high performance mask making E-beam exposure tool, high kV (75 kV) shaped beam system EL4+ and the KRS-XE resist, we have printed 75 nm lines/space features with excellent profile control at a dose of 13 (mu) C/cm2 at 75 kV. The shaped beam vector scan system used here provides an unique property in resolving small features in lithography and throughput. Overhead in EL4+ limits the systems ability to fully exploit the sensitivity of the new resist for throughput. The EL5 system, currently in the build phase, has sufficiently low overhead that it is projected to print a 4X, 16G, DRAM mask with OPC in under 3 hours with the CA resist. We will discuss the throughput advantages of the next generation EL5 system over the existing EL4+. In addition we will show the resolution of KRS-XE down to 70 nm using the PREVAIL projection printing system.

Small-scale thermal studies of volatile homemade explosives

DOE PAGES

Sandstrom, Mary M.; Brown, Geoffrey W.; Warner, Kirsten F.; ...

2016-01-26

Several homemade or improvised explosive mixtures that either contained volatile components or produced volatile products were examined using standard small-scale safety and thermal (SSST) testing that employed differential scanning calorimetry (DSC) techniques (constant heating rate and standard sample holders). KClO 3 and KClO 4 mixtures with dodecane exhibited different enthalpy behavior when using a vented sample holder in contrast to a sealed sample holder. The standard configuration produced profiles that exhibited only endothermic transitions. The sealed system produced profiles that exhibited additional exothermic transitions absent in the standard configuration produced profiles. When H 2O 2/fuel mixtures were examined, the volatilizationmore » of the peroxide (endothermic) dominated the profiles. When a sealed sample holder was used, the energetic releases of the mixture could be clearly observed. For AN and AN mixtures, the high temperature decomposition appears as an intense endothermic event. Using a nominally sealed sample holder also did not adequately contain the system. Only when a high-pressure rated sample holder was used the high temperature decomposition of the AN could be detected as an exothermic release. The testing was conducted during a proficiency (or round-robin type) test that included three U.S. Department of Energy and two U.S. Department of Defense laboratories. In the course of this proficiency test, certain HMEs exhibited thermal behavior that was not adequately accounted for by standard techniques. Further examination of this atypical behavior highlighted issues that may have not been recognized previously because some of these materials are not routinely tested. More importantly, if not recognized, the SSST testing results could lead to inaccurate safety assessments. Furthermore, this study provides examples, where standard techniques can be applied, and results can be obtained, but these results may be misleading in establishing thermal properties.« less

BET surface area distributions in polar stream sediments: Implications for silicate weathering in a cold-arid environment

USGS Publications Warehouse

Marra, Kristen R.; Elwood Madden, Megan E; Soreghan, Gerilyn S.; Hall, Brenda L

2014-01-01

BET surface area values are critical for quantifying the amount of potentially reactive sediments available for chemical weathering and ultimately, prediction of silicate weathering fluxes. BET surface area values of fine-grained (<62.5 μm) sediment from the hyporheic zone of polar glacial streams in the McMurdo Dry Valleys, Antarctica (Wright and Taylor Valleys) exhibit a wide range (2.5–70.6 m2/g) of surface area values. Samples from one (Delta Stream, Taylor Valley) of the four sampled stream transects exhibit high values (up to 70.6 m2/g), which greatly exceed surface area values from three temperate proglacial streams (0.3–12.1 m2/g). Only Clark stream in Wright Valley exhibits a robust trend with distance, wherein surface area systematically decreases (and particle size increases) in the mud fraction downstream, interpreted to reflect rapid dissolution processes in the weathering environment. The remaining transects exhibit a range in variability in surface area distributions along the length of the channel, likely related to variations in eolian input to exposed channel beds, adjacent snow drifts, and to glacier surfaces, where dust is trapped and subsequently liberated during summer melting. Additionally, variations in stream discharge rate, which mobilizes sediment in pulses and influences water:rock ratios, the origin and nature of the underlying drift material, and the contribution of organic acids may play significant roles in the production and mobilization of high-surface area sediment. This study highlights the presence of sediments with high surface area in cold-based glacier systems, which influences models of chemical denudation rates and the impact of glacial systems on the global carbon cycle.

Feasibility of light-emitting diode uses for annular reactor inner-coated with TiO2 or nitrogen-doped TiO2 for control of dimethyl sulfide.

PubMed

Jo, Wan-Kuen; Eun, Sung-Soo; Shin, Seung-Ho

2011-01-01

Limited environmental pollutants have only been investigated for the feasibility of light-emitting diodes (LED) uses in photocatalytic decomposition (PD). The present study investigated the applicability of LEDs for annular photocatalytic reactors by comparing PD efficiencies of dimethyl sulfide (DMS), which has not been investigated with any LED-PD system, between photocatalytic systems utilizing conventional and various LED lamps with different wavelengths. A conventional 8 W UV/TiO(2) system exhibited a higher DMS PD efficiency as compared with UV-LED/TiO(2) system. Similarly, a conventional 8 W visible-lamp/N-enhanced TiO(2) (NET) system exhibited a higher PD efficiency as compared with six visible-LED/NET systems. However, the ratios of PD efficiency to the electric power consumption were rather high for the photocatalytic systems using UV- or visible-LED lamps, except for two LED lamps (yellow- and red-LED lamps), compared to the photocatalytic systems using conventional lamps. For the photocatalytic systems using LEDs, lower flow rates and input concentrations and shorter hydraulic diameters exhibited higher DMS PD efficiencies. An Fourier-transformation infrared analysis suggested no significant absorption of byproducts on the catalyst surface. Consequently, it was suggested that LEDs can still be energy-efficiently utilized as alternative light sources for the PD of DMS, under the operational conditions used in this study. © 2011 The Authors. Photochemistry and Photobiology © 2011 The American Society of Photobiology.

Development of Ciprofloxacin-loaded contact lenses using fluorous chemistry

PubMed Central

Zhu, Zhiling; Li, Siheng; McDermott, Alison M.

2017-01-01

In this work, we developed a simple method to load drugs into commercially available contact lenses utilizing fluorous chemistry. We demonstrated this method using model compounds including fluorous-tagged fluorescein and antibiotic ciprofloxacin. We showed that fluorous interactions facilitated the loading of model molecules into fluorocarbon-containing contact lenses, and that the release profiles exhibited sustained release. Contact lenses loaded with fluorous-tagged ciprofloxacin exhibited antimicrobial activity against Pseudomonas aeruginosa in vitro, while no cytotoxicity towards human corneal epithelial cells was observed. To mimic the tear turnover, we designed a porcine eye infection model under flow conditions. Significantly, the modified lenses also exhibited antimicrobial efficacy against Pseudomonas aeruginosa in the ex vivo infection model. Overall, utilizing fluorous chemistry, we can construct a drug delivery system that exhibits high drug loading capacity, sustained drug release, and robust biological activity. PMID:28188995

High-power 0.87-micron channel substrate planar lasers for spaceborne communications

NASA Technical Reports Server (NTRS)

Connolly, J. C.; Stewart, T. R.; Gilbert, D. B.; Slavin, S. E.; Carlin, D. B.

1988-01-01

High-power single-mode channeled-substrate planar AlGaAs diode lasers are being developed for reliable high-power operation for use as sources in spaceborne optical communication systems. The CSP laser structure has been optimized for operation at an emission wavelength of 870 nm. Such devices have exhibited output powers in excess of 80 mW CW at an operating temperature of 80 C.

Application of an imaging system to a museum exhibition for developing interactive exhibitions

NASA Astrophysics Data System (ADS)

Miyata, Kimiyoshi; Inoue, Yuka; Takiguchi, Takahiro; Tsumura, Norimichi; Nakaguchi, Toshiya; Miyake, Yoichi

2009-10-01

In the National Museum of Japanese History, 215,759 artifacts are stored and used for research and exhibitions. In museums, due to the limitation of space in the galleries, a guidance system is required to satisfy visitors' needs and to enhance their understanding of the artifacts. We introduce one exhibition using imaging technology to improve visitors' understanding of a kimono (traditional Japanese clothing) exhibition. In the imaging technology introduced, one data projector, one display with touch panel interface, and magnifiers were used as exhibition tools together with a real kimono. The validity of this exhibition method was confirmed by results from a visitors' interview survey. Second, to further develop the interactive guidance system, an augmented reality system that consisted of cooperation between the projector and a digital video camera was also examined. A white paper board in the observer's hand was used as a projection screen and also as an interface to control the images projected on the board. The basic performance of the proposed system was confirmed; however continuous development was necessary for applying the system to actual exhibitions.

Roles of dispersal, stochasticity, and nonlinear dynamics in the spatial structuring of seasonal natural enemy-victim populations

Treesearch

Patrick C. Tobin; Ottar N. Bjornstad

2005-01-01

Natural enemy-victim systems may exhibit a range of dynamic space-time patterns. We used a theoretical framework to study spatiotemporal structuring in a transient natural enemy-victim system subject to differential rates of dispersal, stochastic forcing, and nonlinear dynamics. Highly mobile natural enemies that attacked less mobile victims were locally spatially...

Modeling a flexible representation machinery of human concept learning.

PubMed

Matsuka, Toshihiko; Sakamoto, Yasuaki; Chouchourelou, Arieta

2008-01-01

It is widely acknowledged that categorically organized abstract knowledge plays a significant role in high-order human cognition. Yet, there are many unknown issues about the nature of how categories are internally represented in our mind. Traditionally, it has been considered that there is a single innate internal representation system for categorical knowledge, such as Exemplars, Prototypes, or Rules. However, results of recent empirical and computational studies collectively suggest that the human internal representation system is apparently capable of exhibiting behaviors consistent with various types of internal representation schemes. We, then, hypothesized that humans' representational system as a dynamic mechanism, capable of selecting a representation scheme that meets situational characteristics, including complexities of category structure. The present paper introduces a framework for a cognitive model that integrates robust and flexible internal representation machinery. Three simulation studies were conducted. The results showed that SUPERSET, our new model, successfully exhibited cognitive behaviors that are consistent with three main theories of the human internal representation system. Furthermore, a simulation study on social cognitive behaviors showed that the model was capable of acquiring knowledge with high commonality, even for a category structure with numerous valid conceptualizations.

Jamming Behavior of Domain Walls in an Antiferromagnetic Film

NASA Astrophysics Data System (ADS)

Sinha, Sunil

2014-03-01

Over the last few years, attempts have been made to unify many aspects of the freezing behavior of glasses, granular materials, gels, supercooled liquids, etc. into a general conceptual framework of what is called jamming behavior. This occurs when particles reach packing densities high enough that their motions become highly restricted. A general phase diagram has been proposed onto which various materials systems, e.g glasses or granular materials, can be mapped. We will discuss some recent applications of resonant and non-resonant soft X-ray Grazing Incidence Scattering to mesoscopic science, for example the study of magnetic domain wall fluctuations in thin films. For these studies, we use resonant magnetic x-ray scattering with a coherent photon beam and the technique of X-ray Photon Correlation Spectroscopy. find that at the ordering temperature the domains of an antiferromagnetic system, namely Dysprosium metal, behave very much also like a jammed system and their associated fluctuations exhibit behavior which exhibit some of the universal characteristics of jammed systems, such as non-exponential relaxation and Vogel-Fulcher type freezing. Work supported by Basic Energy Sciences, U.S. Dept. of Energy under Grant Number: DE-SC0003678.

A Flexible High-Performance Photoimaging Device Based on Bioinspired Hierarchical Multiple-Patterned Plasmonic Nanostructures.

PubMed

Lee, Yoon Ho; Lee, Tae Kyung; Kim, Hongki; Song, Inho; Lee, Jiwon; Kang, Saewon; Ko, Hyunhyub; Kwak, Sang Kyu; Oh, Joon Hak

2018-03-01

In insect eyes, ommatidia with hierarchical structured cornea play a critical role in amplifying and transferring visual signals to the brain through optic nerves, enabling the perception of various visual signals. Here, inspired by the structure and functions of insect ommatidia, a flexible photoimaging device is reported that can simultaneously detect and record incoming photonic signals by vertically stacking an organic photodiode and resistive memory device. A single-layered, hierarchical multiple-patterned back reflector that can exhibit various plasmonic effects is incorporated into the organic photodiode. The multiple-patterned flexible organic photodiodes exhibit greatly enhanced photoresponsivity due to the increased light absorption in comparison with the flat systems. Moreover, the flexible photoimaging device shows a well-resolved spatiotemporal mapping of optical signals with excellent operational and mechanical stabilities at low driving voltages below half of the flat systems. Theoretical calculation and scanning near-field optical microscopy analyses clearly reveal that multiple-patterned electrodes have much stronger surface plasmon coupling than flat and single-patterned systems. The developed methodology provides a versatile and effective route for realizing high-performance optoelectronic and photonic systems. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Unsupervised Learning and Pattern Recognition of Biological Data Structures with Density Functional Theory and Machine Learning.

PubMed

Chen, Chien-Chang; Juan, Hung-Hui; Tsai, Meng-Yuan; Lu, Henry Horng-Shing

2018-01-11

By introducing the methods of machine learning into the density functional theory, we made a detour for the construction of the most probable density function, which can be estimated by learning relevant features from the system of interest. Using the properties of universal functional, the vital core of density functional theory, the most probable cluster numbers and the corresponding cluster boundaries in a studying system can be simultaneously and automatically determined and the plausibility is erected on the Hohenberg-Kohn theorems. For the method validation and pragmatic applications, interdisciplinary problems from physical to biological systems were enumerated. The amalgamation of uncharged atomic clusters validated the unsupervised searching process of the cluster numbers and the corresponding cluster boundaries were exhibited likewise. High accurate clustering results of the Fisher's iris dataset showed the feasibility and the flexibility of the proposed scheme. Brain tumor detections from low-dimensional magnetic resonance imaging datasets and segmentations of high-dimensional neural network imageries in the Brainbow system were also used to inspect the method practicality. The experimental results exhibit the successful connection between the physical theory and the machine learning methods and will benefit the clinical diagnoses.

Engaging high school students as plasma science outreach ambassadors

NASA Astrophysics Data System (ADS)

Wendt, Amy; Boffard, John

2017-10-01

Exposure to plasma science among future scientists and engineers is haphazard. In the U.S., plasma science is rare (or absent) in mainstream high school and introductory college physics curricula. As a result, talented students may be drawn to other careers simply due to a lack of awareness of the stimulating science and wide array of fulfilling career opportunities involving plasmas. In the interest of enabling informed decisions about career options, we have initiated an outreach collaboration with the Madison West High School Rocket Club. Rocket Club members regularly exhibit their activities at public venues, including large-scale expos that draw large audiences of all ages. Building on their historical emphasis on small scale rockets with chemical motors, we worked with the group to add a new feature to their exhibit that highlights plasma-based spacecraft propulsion for interplanetary probes. This new exhibit includes a model satellite with a working (low power) plasma thruster. The participating high school students led the development process, to be described, and enthusiastically learned to articulate concepts related to plasma thruster operation and to compare the relative advantages of chemical vs. plasma/electrical propulsion systems for different scenarios. Supported by NSF Grant PHY-1617602.

Atomtronics: Realizing the behavior of electronic components in ultracold atomic systems

NASA Astrophysics Data System (ADS)

Pepino, Ron

2007-06-01

Atomtronics focuses on creating an analogy of electronic devices and circuits with ultracold atoms. Such an analogy can come from the highly tunable band structure of ultracold neutral atoms trapped in optical lattices. Solely by tuning the parameters of the optical lattice, we demonstrate that conditions can be created that cause atoms in lattices to exhibit the same behavior as electrons moving through solid state media. We present our model and show how the atomtronic diode, field effect transistor, and bipolar junction transistor can all be realized. Our analogs of these fundamental components exhibit precisely-controlled atomic signal amplification, trimming, and switching (on/off) characteristics. In addition, the evolution of dynamics of the superfluid atomic currents within these systems is completely reversible. This implies a possible use of atomtronic systems in the development of quantum computational devices.

Reynolds numbers exhibit dramatic influence on directionality of movement of self-propelled systems.

PubMed

Zhao, Guanjia; Pumera, Martin

2012-05-14

Self-propelled artificial objects are at the current forefront of research. We demonstrate here that the motion directionality of millimetre sized self-propelled objects is highly dependent on the Reynolds numbers (Re) of the systems, with emphasis on the "intermediate" Re region (1-600). Our findings have strong implication on the motion controllability and predictability of these independent self-propelled systems. This journal is © the Owner Societies 2012

Hard-Soft Composite Carbon as a Long-Cycling and High-Rate Anode for Potassium-Ion Batteries

DOE PAGES

Jian, Zelang; Hwang, Sooyeon; Li, Zhifei; ...

2017-05-05

There exist tremendous needs for sustainable storage solutions for intermittent renewable energy sources, such as solar and wind energy. Thus, systems based on Earth-abundant elements deserve much attention. Potassium-ion batteries represent a promising candidate because of the abundance of potassium resources. As for the choices of anodes, graphite exhibits encouraging potassium-ion storage properties; however, it suffers limited rate capability and poor cycling stability. Here in this paper, nongraphitic carbons as K-ion anodes with sodium carboxymethyl cellulose as the binder are systematically investigated. Compared to hard carbon and soft carbon, a hard–soft composite carbon with 20 wt% soft carbon distributed inmore » the matrix phase of hard carbon microspheres exhibits highly amenable performance: high capacity, high rate capability, and very stable long-term cycling. In contrast, pure hard carbon suffers limited rate capability, while the capacity of pure soft carbon fades more rapidly.« less

Hard-Soft Composite Carbon as a Long-Cycling and High-Rate Anode for Potassium-Ion Batteries

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

Jian, Zelang; Hwang, Sooyeon; Li, Zhifei

There exist tremendous needs for sustainable storage solutions for intermittent renewable energy sources, such as solar and wind energy. Thus, systems based on Earth-abundant elements deserve much attention. Potassium-ion batteries represent a promising candidate because of the abundance of potassium resources. As for the choices of anodes, graphite exhibits encouraging potassium-ion storage properties; however, it suffers limited rate capability and poor cycling stability. Here in this paper, nongraphitic carbons as K-ion anodes with sodium carboxymethyl cellulose as the binder are systematically investigated. Compared to hard carbon and soft carbon, a hard–soft composite carbon with 20 wt% soft carbon distributed inmore » the matrix phase of hard carbon microspheres exhibits highly amenable performance: high capacity, high rate capability, and very stable long-term cycling. In contrast, pure hard carbon suffers limited rate capability, while the capacity of pure soft carbon fades more rapidly.« less

Sharing the Data along with the Responsibility: Examining an Analytic Scale-Based Model for Assessing School Climate.

ERIC Educational Resources Information Center

Shindler, John; Taylor, Clint; Cadenas, Herminia; Jones, Albert

This study was a pilot effort to examine the efficacy of an analytic trait scale school climate assessment instrument and democratic change system in two urban high schools. Pilot study results indicate that the instrument shows promising soundness in that it exhibited high levels of validity and reliability. In addition, the analytic trait format…

Gas barrier properties of bio-inspired Laponite-LC polymer hybrid films.

PubMed

Tritschler, Ulrich; Zlotnikov, Igor; Fratzl, Peter; Schlaad, Helmut; Grüner, Simon; Cölfen, Helmut

2016-05-26

Bio-inspired Laponite (clay)-liquid crystal (LC) polymer composite materials with high clay fractions (>80%) and a high level of orientation of the clay platelets, i.e. with structural features similar to the ones found in natural nacre, have been shown to exhibit a promising behavior in the context of reduced oxygen transmission. Key characteristics of these bio-inspired composite materials are their high inorganic content, high level of exfoliation and orientation of the clay platelets, and the use of a LC polymer forming the organic matrix in between the Laponite particles. Each single feature may be beneficial to increase the materials gas barrier property rendering this composite a promising system with advantageous barrier capacities. In this detailed study, Laponite/LC polymer composite coatings with different clay loadings were investigated regarding their oxygen transmission rate. The obtained gas barrier performance was linked to the quality, respective Laponite content and the underlying composite micro- and nanostructure of the coatings. Most efficient oxygen barrier properties were observed for composite coatings with 83% Laponite loading that exhibit a structure similar to sheet-like nacre. Further on, advantageous mechanical properties of these Laponite/LC polymer composites reported previously give rise to a multifunctional composite system.

10J water-cooled DPSSL system based on Yb:YAG crystal edge-cladded by Cr:YAG ceramics (Conference Presentation)

NASA Astrophysics Data System (ADS)

Zheng, Jian-Gang; Yan, Xiongwei; Jiang, Xinying; Wang, Zhenguo; Li, Mingzhong; Zhang, Jun; Zhu, Qihua; Zheng, Wanguo

2017-05-01

Laser Inertial Fusion Energy (IFE) has been attracting the interests of the researchers around the world, because of the promising to the future energy. The Yb:YAG was broadly used in the research field of high-peak power and large energy laser with repetition-rate for IFE because of its outstanding performance, including significant thermal and mechanical capacities, long upper energy level lifetime, high quantum efficiency and highly doping capacity. But it exhibits high saturation fluence at room temperature because of the small emission and absorption cross-section. And at the same time this gain material exhibits self-absorption of laser because of the thermal population at lower laser level at room temperature. Ant it appears to have been solved by means of the cryogenic temperature, but the total efficiency of the laser system will be decreased as the use of cryogenic temperature. The amplified spontaneous emission (ASE) effect of the amplifier can be relaxed by means of edge-cladded absorption material. And the difficulties of edge cladding can be will solved as the emergence of ceramics. But at present the ceramics exhibits high scattering and many disfigurements, which limited the application in the high-power large-energy laser system. So the edge-cladding of Yb:YAG crystal will be a key issue for solution the ASE in amplifier. In this paper, we will introduce a 10J water-cooled DPSSL system, based on Yb:YAG crystal at room temperature. In this system a new edge cladding method has been used, that the Yb:YAG crystal was edge cladded by Cr:YAG ceramics, which was used as the absorption material of ASE. The amplifier was an active mirror water-cooled room temperature amplifier. With the help of this edge cladding the ASE has been lowered, and about 5 times small signal gain has been obtained in a single pass amplification, which was much higher than the earlier of 2 times. And the wavefront aberrance of the laser beam was also reduced due to the thermal equilibrium between the edge cladding and the gain region. the amplifiers can be stably operated under 10Hz. Finally the output of the laser system was about 7.15J@10Hz and 10.8J@1-2Hz. The total optical-to-optical efficiency was about 8.3% for 1-2Hz (under the condition of 120kW/1ms pumping, 880mJ input and 10.8J output) and 5.6% for 10Hz.

Synthesis of high density aviation fuel with cyclopentanol derived from lignocellulose

NASA Astrophysics Data System (ADS)

Sheng, Xueru; Li, Ning; Li, Guangyi; Wang, Wentao; Yang, Jinfan; Cong, Yu; Wang, Aiqin; Wang, Xiaodong; Zhang, Tao

2015-03-01

For the first time, renewable high density aviation fuels were synthesized at high overall yield (95.6%) by the Guerbet reaction of cyclopentanol which can be derived from lignocellulose, followed by the hydrodeoxygenation (HDO). The solvent-free Guerbet reaction of cyclopentanol was carried out under the co-catalysis of solid bases and Raney metals. Among the investigated catalyst systems, the combinations of magnesium-aluminium hydrotalcite (MgAl-HT) and Raney Ni (or Raney Co) exhibited the best performances. Over them, high carbon yield (96.7%) of C10 and C15 oxygenates was achieved. The Guerbet reaction products were further hydrodeoxygenated to bi(cyclopentane) and tri(cyclopentane) over a series of Ni catalysts. These alkanes have high densities (0.86 g mL-1 and 0.91 g mL-1) and can be used as high density aviation fuels or additives to bio-jet fuel. Among the investigated HDO catalysts, the 35 wt.% Ni-SiO2-DP prepared by deposition-precipitation method exhibited the highest activity.

Synthesis of high density aviation fuel with cyclopentanol derived from lignocellulose.

PubMed

Sheng, Xueru; Li, Ning; Li, Guangyi; Wang, Wentao; Yang, Jinfan; Cong, Yu; Wang, Aiqin; Wang, Xiaodong; Zhang, Tao

2015-03-31

For the first time, renewable high density aviation fuels were synthesized at high overall yield (95.6%) by the Guerbet reaction of cyclopentanol which can be derived from lignocellulose, followed by the hydrodeoxygenation (HDO). The solvent-free Guerbet reaction of cyclopentanol was carried out under the co-catalysis of solid bases and Raney metals. Among the investigated catalyst systems, the combinations of magnesium-aluminium hydrotalcite (MgAl-HT) and Raney Ni (or Raney Co) exhibited the best performances. Over them, high carbon yield (96.7%) of C10 and C15 oxygenates was achieved. The Guerbet reaction products were further hydrodeoxygenated to bi(cyclopentane) and tri(cyclopentane) over a series of Ni catalysts. These alkanes have high densities (0.86 g mL(-1) and 0.91 g mL(-1)) and can be used as high density aviation fuels or additives to bio-jet fuel. Among the investigated HDO catalysts, the 35 wt.% Ni-SiO2-DP prepared by deposition-precipitation method exhibited the highest activity.

Advances in the T7 phage display system (Review).

PubMed

Deng, Xiangying; Wang, Li; You, Xiaolong; Dai, Pei; Zeng, Yanhua

2018-01-01

The present review describes the advantages and updated applications of the T7 phage display system in bioscience and medical science. Current phage display systems are based on various bacteriophage vectors, including M13, T7, T4 and f1. Of these, the M13 phage display is the most frequently used, however, the present review highlights the advantages of the T7 system. As a phage display platform, M13 contains single‑stranded DNA, while the T7 phage consists of double‑stranded DNA, which exhibits increased stability and is less prone to mutation during replication. Additional characteristics of the T7 phage include the following: The T7 phage does not depend on a protein secretion pathway in the lytic cycle; expressed peptides and proteins are usually located on the C‑terminal region of capsid protein gp10B, which avoids problems associated with steric hindrance; and T7 phage particles exhibit high stability under various extreme conditions, including high temperature and low pH, which facilitates effective high‑throughput affinity elutriation. Recent applications of the T7 phage display system have been instrumental in uncovering mechanisms of molecular interaction, particularly in the fields of antigen discovery, vaccine development, protein interaction, and cancer diagnosis and treatment.

An infinitely-stiff elastic system via a tuned negative-stiffness component stabilized by rotation-produced gyroscopic forces

NASA Astrophysics Data System (ADS)

Kochmann, D. M.; Drugan, W. J.

2016-06-01

An elastic system containing a negative-stiffness element tuned to produce positive-infinite system stiffness, although statically unstable as is any such elastic system if unconstrained, is proved to be stabilized by rotation-produced gyroscopic forces at sufficiently high rotation rates. This is accomplished in possibly the simplest model of a composite structure (or solid) containing a negative-stiffness component that exhibits all these features, facilitating a conceptually and mathematically transparent, completely closed-form analysis.

Fully solar-powered photoelectrochemical conversion for simultaneous energy storage and chemical sensing.

PubMed

Wang, Yongcheng; Tang, Jing; Peng, Zheng; Wang, Yuhang; Jia, Dingsi; Kong, Biao; Elzatahry, Ahmed A; Zhao, Dongyuan; Zheng, Gengfeng

2014-06-11

We report the development of a multifunctional, solar-powered photoelectrochemical (PEC)-pseudocapacitive-sensing material system for simultaneous solar energy conversion, electrochemical energy storage, and chemical detection. The TiO2 nanowire/NiO nanoflakes and the Si nanowire/Pt nanoparticle composites are used as photoanodes and photocathodes, respectively. A stable open-circuit voltage of ∼0.45 V and a high pseudocapacitance of up to ∼455 F g(-1) are obtained, which also exhibit a repeating charging-discharging capability. The PEC-pseudocapacitive device is fully solar powered, without the need of any external power supply. Moreover, this TiO2 nanowire/NiO nanoflake composite photoanode exhibits excellent glucose sensitivity and selectivity. Under the sun light illumination, the PEC photocurrent shows a sensitive increase upon different glucose additions. Meanwhile in the dark, the open-circuit voltage of the charged pseudocapacitor also exhibits a corresponding signal over glucose analyte, thus serving as a full solar-powered energy conversion-storage-utilization system.

Design, characterization, and biological evaluation of curcumin-loaded surfactant-based systems for topical drug delivery.

PubMed

Fonseca-Santos, Bruno; Dos Santos, Aline Martins; Rodero, Camila Fernanda; Gremião, Maria Palmira Daflon; Chorilli, Marlus

From previous studies, it has been found that curcumin exhibits an anti-inflammatory activity and is being used for the treatment of skin disorders; however, it is hydrophobic and has weak penetrating ability, resulting in poor drug transport through the stratum corneum. The aim of this study was to develop liquid crystalline systems for topical administration of curcumin for the treatment of inflammation. These liquid crystalline systems were developed from oleic acid, polyoxypropylene (5) polyoxyethylene (20) cetyl alcohol, and water as the surfactant, oil phase, and aqueous phase, respectively. These systems were characterized, and polarized light microscopy showed anisotropy with lamellar mesophases (Formulation 1) and hexagonal mesophases (Formulations 2 and 3), which were confirmed by the peak ratio measured using small-angle X-ray scattering. In addition, rheological tests revealed that the formulations exhibited gel-like behavior (G'>G″), as evidenced by the increased G' values that indicate structured systems. Texture profile analysis showed that hexagonal mesophases have high values of hardness, adhesiveness, and compressibility, which indicate structured systems. In vitro studies on bioadhesion revealed that the hexagonal mesophases increased the bioadhesiveness of the systems to the skin of the pig ear. An in vivo inflammation experiment showed that the curcumin-loaded hexagonal mesophase exhibited an anti-inflammatory activity as compared to the positive control (dexamethasone). The results suggest that this system has a potential to be used as a bioadhesive vehicle for the topical administration of curcumin. Therefore, it is possible to conclude that these systems can be used for the optimization of drug delivery systems to the skin.

Geometric Magnetic Frustration in Li3Mg2OsO6 Studied with Muon Spin Relaxation

NASA Astrophysics Data System (ADS)

Carlo, J. P.; Derakhshan, S.; Greedan, J. E.

Geometric frustration manifests when the spatial arrangement of ions inhibits magnetic order. Typically associated with antiferromagnetically (AF)-correlated moments on triangular or tetrahedral lattices, frustration occurs in a variety of structures and systems, resulting in rich phase diagrams and exotic ground states. As a window to exotic physics revealed by the cancellation of normally dominant interactions, the research community has taken great interest in frustrated systems. One family of recent interest are the rock-salt ordered oxides A5BO6, in which the B sites are occupied by magnetic ions comprising a network of interlocked tetrahedra, and nonmagnetic ions on the A sites control the B oxidation state through charge neutrality. Here we will discuss studies of Li3Mg2OsO6 using muon spin relaxation (μSR), a highly sensitive local probe of magnetism. Previous studies of this family included Li5OsO6, which exhibits AF order below 50K with minimal evidence for frustration, and Li4MgReO6, which exhibits glassy magnetism. Li3Mg2RuO6, meanwhile, exhibits long-range AF, with the ordering temperature suppressed by frustration. But its isoelectronic twin, Li3Mg2OsO6 (5d3 vs. 4d3) exhibits very different behavior, revealed by μSR to be a glassy ground state below 12K. Understanding why such similar systems exhibit diverse ground-state behavior is key to understanding the nature of geometric magnetic frustration. Financial support from the Research Corporation for Science Advancement.

Studies on polar high-speed counter-current chromatographic systems in separation of amaranthine-type betacyanins from Celosia species.

PubMed

Spórna-Kucab, Aneta; Milo, Angelika; Kumorkiewicz, Agnieszka; Wybraniec, Sławomir

2018-01-15

Betacyanins, natural plant pigments exhibiting antioxidant and chemopreventive properties, were extracted from Celosia spicata (Thouars) Spreng. inflorescences and separated by high-speed counter-current chromatography (HSCCC) in two polar solvent systems composed of: TBME - 1-BuOH - ACN - H 2 O (0.7% HFBA, 2:2:1:5, v/v/v/v) (system I) and EtOH - ACN - 1-PrOH - (NH 4 ) 2 SO 4satd.soln - H 2 O (0.5:0.5:0.5:1.2:1, v/v/v/v/v) (system II). The systems were used in the head-to-tail (system I) and tail-to-head (system II) mode. The flow rate of the mobile phase was 2.0 ml/min and the column rotation speed was 860 rpm. The retention of the stationary phase was 73.5% (system I) and 80.0% (system II). For the identification of separated betacyanins in the crude extract as well as in the HSCCC fractions, LC-DAD-ESI-MS/MS analyses were performed. Depending on the target compounds, each of the systems exhibit meaningfully different selectivity and applicability. For the pairs of amaranthines (1/1') and betanins (2/2'), the best choice is the system II, but the acylated amaranthine pairs (3/3' and 4/4') can be resolved only in the ion-pair system I. For the indication of the most suitable solvent system for Celosia plumosa hort., Celosia cristata L. and Celosia spicata (Thouars) Spreng. species, the profiles of betacyanins in different plant parts were studied. Copyright © 2017. Published by Elsevier B.V.

A Solar Dynamic Power Option for Space Solar Power

NASA Technical Reports Server (NTRS)

Mason, Lee S.

1999-01-01

A study was performed to determine the potential performance and related technology requirements of Solar Dynamic power systems for a Space Solar Power satellite. Space Solar Power is a concept where solar energy is collected in orbit and beamed to Earth receiving stations to supplement terrestrial electric power service. Solar Dynamic systems offer the benefits of high solar-to-electric efficiency, long life with minimal performance degradation, and high power scalability. System analyses indicate that with moderate component development, SD systems can exhibit excellent mass and deployed area characteristics. Using the analyses as a guide, a technology roadmap was -enerated which identifies the component advances necessary to make SD power generation a competitive option for the SSP mission.

Microstructural effects on ignition sensitivity in Ni/Al systems subjected to high strain rate impacts

NASA Astrophysics Data System (ADS)

Reeves, Robert; Mukasyan, Alexander; Son, Steven

2011-06-01

The effect of microstructural refinement on the sensitivity of the Ni/Al (1:1 at%) system to ignition via high strain rate impacts is investigated. The tested microstructures include compacts of irregularly convoluted lamellar structures with nanometric features created through high-energy ball milling (HEBM) of micron size Ni/Al powders and compacts of nanometric Ni and Al powders. The test materials were subjected to high strain rate impacts through Asay shear experiments powered by a light gas gun. Muzzle velocities up to 1.1 km/s were used. It was found that the nanometric powder exhibited a greater sensitivity to ignition via impact than the HEBM material, despite greater thermal sensitivity of the HEBM. A previously unseen fast reaction mode where the reaction front traveled at the speed of the input stress wave was also observed in the nanometric mixtures at high muzzle energies. This fast mode is considered to be a mechanically induced thermal explosion mode dependent on the magnitude of the traveling stress wave, rather than a self-propagating detonation, since its propagation rate decreases rapidly across the sample. A similar mode is not exhibited by HEBM samples, although local, nonpropagating reaction zones occur in shear bands formed during the impact event.

Microstructural effects on ignition sensitivity in Ni/Al systems subjected to high strain rate impacts

NASA Astrophysics Data System (ADS)

Reeves, Robert V.; Mukasyan, Alexander S.; Son, Steven

2012-03-01

The effect of microstructural refinement on the sensitivity of the Ni/Al (1:1 mol%) system to ignition via high strain rate impacts is investigated. The tested microstructures include compacts of irregularly convoluted lamellar structures with nanometric features created through high-energy ball milling (HEBM) of micron size Ni/Al powders and compacts of nanometric Ni and Al powders. The test materials were subjected to high strain rate impacts through Asay shear experiments powered by a light gas gun. Muzzle velocities up to 1.1 km/s were used. It was found that the nanometric powder exhibited a greater sensitivity to ignition via impact than the HEBM material, despite greater thermal sensitivity of the HEBM. A previously unseen fast reaction mode where the reaction front traveled at the speed of the input stress wave was also observed in the nanometric mixtures at high muzzle energies. This fast mode is considered to be a mechanically induced thermal explosion mode dependent on the magnitude of the traveling stress wave, rather than a self-propagating detonation, since its propagation rate decreases rapidly across the sample. A similar mode is not exhibited by HEBM samples, although local, nonpropagating reaction zones shear bands formed during the impact event are observed.

152 W average power Tm-doped fiber CPA system.

PubMed

Stutzki, Fabian; Gaida, Christian; Gebhardt, Martin; Jansen, Florian; Wienke, Andreas; Zeitner, Uwe; Fuchs, Frank; Jauregui, Cesar; Wandt, Dieter; Kracht, Dietmar; Limpert, Jens; Tünnermann, Andreas

2014-08-15

A high-power thulium (Tm)-doped fiber chirped-pulse amplification system emitting a record compressed average output power of 152 W and 4 MW peak power is demonstrated. This result is enabled by utilizing Tm-doped photonic crystal fibers with mode-field diameters of 35 μm, which mitigate detrimental nonlinearities, exhibit slope efficiencies of more than 50%, and allow for reaching a pump-power-limited average output power of 241 W. The high-compression efficiency has been achieved by using multilayer dielectric gratings with diffraction efficiencies higher than 98%.

Subsurface Thermal Energy Storage for Improved Heating and Air Conditioning Efficiency

DTIC Science & Technology

2016-11-21

This project involved a field demonstration of subsurface thermal energy storage for improving the geothermal heat pump air conditioning efficiency... geothermal heat pump systems, undesirable heating of the ground may occur. This demonstration was performed at the MCAS, Beaufort, SC, where several...buildings with geothermal heat pump systems were exhibiting excessively high ground loop temperatures. These buildings were retrofitted with dry fluid

Why is bidirectional sex change rare?

PubMed

Yamaguchi, Sachi; Iwasa, Yoh

2018-09-14

Various species of fish living in coral reef communities show sequential hermaphroditism, or sex change. In a typical case, an individual first matures as a female, and later, when it becomes dominant in the mating group, it becomes a male (i.e., protogynous sex change). Many species show only unidirectional changes but some of coral reef fishes exhibit bidirectional sex changes, in which even a dominant male may revert to female when a socially more dominant competitor arrives. However, bidirectional sex change has rarely been observed in natural conditions, even among those species exhibiting it under experimental conditions. Here we explain the rarity of bidirectional sex change by studying dynamics of hormones controlling sex expression. We consider social status factor, S F , which is elevated when the individual becomes more dominant in the mating group. When the S F level is high, the dynamics would culminate with low estradiol expression and high testosterone expression, suggesting a male phenotype. In contrast, when S F level is low, the system converges to an equilibrium with high estradiol expression and low testosterone expression, suggesting a female phenotype. There is a parameter region in which the dynamics exhibit bistability. The model demonstrates hysteresis: as S F increases smoothly, the system undergoes a sudden transition in the levels of sex hormones. The model can explain why species show unidirectional sex change, in that an individual's switch to a new sex is irreversible, even if the individual's social situation returns to the original subdominant status. Copyright © 2018 Elsevier Ltd. All rights reserved.

Process for preparing high-transition-temperature superconductors in the Nb-Al-Ge system

DOEpatents

Giorgi, A.L.; Szklarz, E.G.

1973-01-30

The patent describes a process for preparing superconducting materials in the Nb-Al-Ge system having transition temperatures in excess of 19K. The process comprises premixing powdered constituents, pressing them into a plug, heating the plug to 1,450-1,800C for 30 minutes to an hour under vacuum or an inert atmosphere, and annealing at moderate temperatures for reasonably long times (approximately 50 hours). High transition-temperature superconductors, including those in the Nb3(Al,Ge) system, prepared in accordance with this process exhibit little degradation in the superconducting transition temperature on being ground to -200 mesh powder. (GRA)

Crystal structure and electrochemical characteristics of non-AB 5 type La-Ni system alloys

NASA Astrophysics Data System (ADS)

Shi, Siqi; Ouyang, Chuying; Lei, Minsheng

The La-Ni system compounds have been prepared by arc-melting method under Ar atmosphere. X-ray diffraction analysis reveals that the as-prepared alloys consist of different phases. The electrochemical properties, including activation, maximum discharge capacity, high rate chargeability (HRC), and high rate dischargeability (HRD) of these alloy electrodes have been studied through the charge-discharge recycle testing at different temperatures and charge (or discharge) currents. Among the La-Ni alloy electrodes studied, LaNi 2.28 alloy has the most excellent high rate charging performance, and La 2Ni 7 alloy exhibit the highest high rate dischargeability, while La 7Ni 3 alloy is capable of discharging at low temperature.

World's highest tides: Hypertidal coastal systems in North America, South America and Europe

NASA Astrophysics Data System (ADS)

Archer, Allen W.

2013-02-01

Hypertidal systems can be defined as areas where spring tides have ranges greater than 6 m. These very high tidal ranges results in unique patterns of sedimentation within hypertidal estuaries. Such systems are not common but they do occur on a number of continents. This report will discuss six areas that have the highest tides in the world. North America hypertidal systems occur within Cook Inlet in Alaska, USA, Leaf Basin in Ungava Bay, Quebec Province, Canada, and the Bay of Fundy, Nova Scotia and New Brunswick, Canada. In South America, the Straits of Magellan and associated Atlantic coastal settings exhibit hypertidal conditions. European hypertidal systems include Bristol Channel and Severn estuary in southwest England and the Gulf of St. Malo in Normandy, France. These six areas have the highest tides in the world and spring tidal ranges that regularly exceed 10 m. All the six areas can be divided into intertidal sedimentological zones. Zone 1 is the outermost zone and contains longitudinal bars. Zone 2 exhibits laterally extensive sand flats. Zone 3 includes the innermost extent of tides and estuarine point bars. Annual and neap-spring cycles have been documented in Zone 3 and are probably the most indicative features of hypertidal systems. The North American systems occur in high-latitude cold climates where winter ice can have a minor or major impact on the development of sedimentary facies. Conversely, the European and Patagonia systems have climates minimal ice formation.

High-capacity NO2 denuder systems operated at various temperatures (298-473 K).

PubMed

Wolf, Jan-Christoph; Niessner, Reinhard

2012-12-01

In this study, we investigated several coatings for high-temperature, high-capacity, and high-efficiency denuder-based NO(2) removal, with the scope to face the harsh conditions and requirements of automotive exhaust gas sampling. As first coating, we propose a potassium iodide (KI)/polyethylene glycol coating with a high removal efficiency (ε > 98%) for about 2 h and 50 ppm NO(2) at room temperature (298 K). At elevated temperatures (423 K), the initial capacity (100 ppmh) is decreased to 15 ppmh. Furthermore, this is the first proposal of the ionic liquid methyl-butyl-imidazolium iodide ([BMIm(+)][I(-)]) as denuder coating material. At room temperature, this ionic liquid exhibits far greater capacity (300 ppmh) and NO(2) removal efficiency (ε > 99.9%) than KI. Nevertheless, KI exhibits a slightly (~10%) higher capacity at elevated temperatures than [BMIm(+)][I(-)]. Both coatings presented are suitable for applications requiring selective denuding of NO(2) at temperatures up to 423 K.

Three-dimensional porous activated carbon derived from loofah sponge biomass for supercapacitor applications

NASA Astrophysics Data System (ADS)

Su, Xiao-Li; Chen, Jing-Ran; Zheng, Guang-Ping; Yang, Jing-He; Guan, Xin-Xin; Liu, Pu; Zheng, Xiu-Cheng

2018-04-01

Biomass carbon source is generally cheap, environmentally friendly and readily available in high quality and quantity. In this work, a series of loofah sponge-derived activated carbon (SAC-x) with hierarchical porous structures are prepared by KOH chemical activation and used as electrode materials for supercapacitors. The pore size can be easily controllable by changing the dosage of KOH. The optimized material (SAC-4) exhibits a high specific capacitance of 309.6 F g-1 at 1 A g-1 in the three-electrode system using 6 M KOH electrolyte. More importantly, the as-assembled symmetric supercapacitor based on SAC-4 exhibits a high energy density of 16.1 Wh kg-1 at a power density of 160.0 W kg-1 using 1 M Na2SO4 electrolyte. These remarkable results demonstrate the exciting commercial potential of SAC-x for high-performance supercapacitor applications due to their high specific surface area, appropriately porous structure, and the trace heteroatom (O and N) functionalities.

Striking antitumor activity of a methinium system with incorporated quinoxaline unit obtained by spontaneous cyclization.

PubMed

Bříza, T; Králová, J; Dolenský, B; Rimpelová, S; Kejík, Z; Ruml, T; Hajdúch, M; Džubák, P; Mikula, I; Martásek, P; Poučková, P; Král, V

2015-03-02

A novel pentamethinium salt was synthesized with an unforeseen expanded conjugated quinoxaline unit directly incorporated into a pentamethinium chain. The compound exhibited high fluorescence intensity, selective mitochondrial localization, high cytotoxicity, and selectivity toward malignant cell lines, and resulted in remarkable in vivo suppression of tumor growth in mice. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Asymmetric hydrogenation of aromatic ketones by new recyclable ionic tagged ferrocene-ruthenium catalyst system.

PubMed

Xu, Di; Zhou, Zhi-Ming; Dai, Li; Tang, Li-Wei; Zhang, Jun

2015-05-01

Newly developed ferrocene-oxazoline-phosphine ligands containing quaternary ammonium ionic groups exhibited excellent catalytic performance for the ruthenium-catalyzed hydrogenation of aromatic ketonic substrates to give chiral secondary alcohols with high levels of conversions and enantioselectivities. Simple manipulation process, water tolerance, high activity and good recyclable property make this catalysis practical and appealing. Copyright © 2015 Elsevier Ltd. All rights reserved.

Design of Instant Messaging System of Multi-language E-commerce Platform

NASA Astrophysics Data System (ADS)

Yang, Heng; Chen, Xinyi; Li, Jiajia; Cao, Yaru

2017-09-01

This paper aims at researching the message system in the instant messaging system based on the multi-language e-commerce platform in order to design the instant messaging system in multi-language environment and exhibit the national characteristics based information as well as applying national languages to e-commerce. In order to develop beautiful and friendly system interface for the front end of the message system and reduce the development cost, the mature jQuery framework is adopted in this paper. The high-performance server Tomcat is adopted at the back end to process user requests, and MySQL database is adopted for data storage to persistently store user data, and meanwhile Oracle database is adopted as the message buffer for system optimization. Moreover, AJAX technology is adopted for the client to actively pull the newest data from the server at the specified time. In practical application, the system has strong reliability, good expansibility, short response time, high system throughput capacity and high user concurrency.

PScan 1.0: flexible software framework for polygon based multiphoton microscopy

NASA Astrophysics Data System (ADS)

Li, Yongxiao; Lee, Woei Ming

2016-12-01

Multiphoton laser scanning microscopes exhibit highly localized nonlinear optical excitation and are powerful instruments for in-vivo deep tissue imaging. Customized multiphoton microscopy has a significantly superior performance for in-vivo imaging because of precise control over the scanning and detection system. To date, there have been several flexible software platforms catered to custom built microscopy systems i.e. ScanImage, HelioScan, MicroManager, that perform at imaging speeds of 30-100fps. In this paper, we describe a flexible software framework for high speed imaging systems capable of operating from 5 fps to 1600 fps. The software is based on the MATLAB image processing toolbox. It has the capability to communicate directly with a high performing imaging card (Matrox Solios eA/XA), thus retaining high speed acquisition. The program is also designed to communicate with LabVIEW and Fiji for instrument control and image processing. Pscan 1.0 can handle high imaging rates and contains sufficient flexibility for users to adapt to their high speed imaging systems.

Evaluation of three thermal protection systems in a hypersonic high-heating-rate environment induced by an elevon deflected 30 deg

NASA Technical Reports Server (NTRS)

Taylor, A. H.; Jackson, L. R.; Weinstein, I.

1977-01-01

Three thermal protection systems proposed for a hypersonic research airplane were subjected to high heating rates in the Langley 8 foot, high temperature structures tunnel. Metallic heat sink (Lockalloy), reusable surface insulation, and insulator-ablator materials were each tested under similar conditions. The specimens were tested for a 10 second exposure on the windward side of an elevon deflected 30 deg. The metallic heat sink panel exhibited no damage; whereas the reusable surface insulation tiles were debonded from the panel and the insulator-ablator panel eroded through its thickness, thus exposing the aluminum structure to the Mach 7 environment.

A random PCR screening system for the identification of type 1 human herpes simplex virus.

PubMed

Yu, Xuelian; Shi, Bisheng; Gong, Yan; Zhang, Xiaonan; Shen, Silan; Qian, Fangxing; Gu, Shimin; Hu, Yunwen; Yuan, Zhenghong

2009-10-01

Several viral diseases exhibit measles-like symptoms. Differentiation of suspected cases of measles with molecular epidemiological techniques in the laboratory is useful for measles surveillance. In this study, a random PCR screening system was undertaken for the identification of isolates from patients with measles-like symptoms who exhibited cytopathic effects, but who had negative results for measles virus-specific reverse transcription (RT)-PCR and indirect immunofluorescence assays. Sequence analysis of random amplified PCR products showed that they were highly homologous to type 1 human herpes simplex virus (HSV-1). The results were further confirmed by an HSV-1-specific TaqMan real-time PCR assay. The random PCR screening system described in this study provides an efficient procedure for the identification of unknown viral pathogens. Measles-like symptoms can also be caused by HSV-1, suggesting the need to include HSV-1 in differential diagnoses of measles-like diseases.

High-Dimensional Disorder-Driven Phenomena in Weyl Semimetals, Semiconductors, and Related Systems

NASA Astrophysics Data System (ADS)

Syzranov, Sergey V.; Radzihovsky, Leo

2018-03-01

It is commonly believed that a noninteracting disordered electronic system can undergo only the Anderson metal-insulator transition. It has been suggested, however, that a broad class of systems can display disorder-driven transitions distinct from Anderson localization that have manifestations in the disorder-averaged density of states, conductivity, and other observables. Such transitions have received particular attention in the context of recently discovered 3D Weyl and Dirac materials but have also been predicted in cold-atom systems with long-range interactions, quantum kicked rotors, and all sufficiently high-dimensional systems. Moreover, such systems exhibit unconventional behavior of Lifshitz tails, energy-level statistics, and ballistic-transport properties. Here, we review recent progress and the status of results on non-Anderson disorder-driven transitions and related phenomena.

Technology Projections for Solar Dynamic Power

NASA Technical Reports Server (NTRS)

Mason, Lee S.

1999-01-01

Solar Dynamic power systems can offer many potential benefits to Earth orbiting satellites including high solar-to-electric efficiency, long life without performance degradation, and high power capability. A recent integrated system test of a 2 kilowatt SD power system in a simulated space environment has successfully demonstrated technology readiness for space flight. Conceptual design studies of SD power systems have addressed several potential mission applications: a 10 kilowatt LEO satellite, a low power Space Based Radar, and a 30 kilowatt GEO communications satellite. The studies show that with moderate component development, SD systems can exhibit excellent mass and deployed area characteristics. Using the conceptual design studies as a basis, a SD technology roadmap was generated which identifies the component advances necessary to assure SD systems a competitive advantage for future NASA, DOD, and commercial missions.

A fully battery-powered inexpensive spectrophotometric system for high-sensitivity point-of-care analysis on a microfluidic chip

PubMed Central

Dou, Maowei; Lopez, Juan; Rios, Misael; Garcia, Oscar; Xiao, Chuan; Eastman, Michael

2016-01-01

A cost-effective battery-powered spectrophotometric system (BASS) was developed for quantitative point-of-care (POC) analysis on a microfluidic chip. By using methylene blue as a model analyte, we first compared the performance of the BASS with a commercial spectrophotometric system, and further applied the BASS for loop-mediated isothermal amplification (LAMP) detection and subsequent quantitative nucleic acid analysis which exhibited a comparable limit of detection to that of Nanodrop. Compared to the commercial spectrophotometric system, our spectrophotometric system is lower-cost, consumes less reagents, and has a higher detection sensitivity. Most importantly, it does not rely on external power supplies. All these features make our spectrophotometric system highly suitable for a variety of POC analyses, such as field detection. PMID:27143408

Various topological Mott insulators and topological bulk charge pumping in strongly-interacting boson system in one-dimensional superlattice

NASA Astrophysics Data System (ADS)

Kuno, Yoshihito; Shimizu, Keita; Ichinose, Ikuo

2017-12-01

In this paper, we study a one-dimensional boson system in a superlattice potential. This system is experimentally feasible by using ultracold atomic gases, and attracts much attention these days. It is expected that the system has a topological phase called a topological Mott insulator (TMI). We show that in strongly-interacting cases, the competition between the superlattice potential and the on-site interaction leads to various TMIs with a non-vanishing integer Chern number. Compared to the hard-core case, the soft-core boson system exhibits rich phase diagrams including various non-trivial TMIs. By using the exact diagonalization, we obtain detailed bulk-global phase diagrams including the TMIs with high Chern numbers and also various non-topological phases. We also show that in adiabatic experimental setups, the strongly-interacting bosonic TMIs exhibit the topological particle transfer, i.e., the topological charge pumping phenomenon, similarly to weakly-interacting systems. The various TMIs are characterized by topological charge pumping as it is closely related to the Chern number, and therefore the Chern number is to be observed in feasible experiments.

The Prevalence of Social Maladjustment among School-Age Children.

ERIC Educational Resources Information Center

McGhee, Ron L.; Short, Rick Jay

1991-01-01

Investigated prevalence of social maladjustment among students in two rural/suburban school systems. Results from 249 elementary and secondary school teachers indicated that the percentage of students reported as exhibiting characteristics of social maladjustment was sufficiently high to indicate that services beyond special education may be…

Systems biology approaches to understanding conceptus elongation and early pregnancy loss

USDA-ARS?s Scientific Manuscript database

Infertility and subfertility represent major problems in domestic animals and humans. Selection for higher milk production in United States dairy cattle has been very successful during the past 50 years, however the modern lactating dairy cow exhibits a high incidence of subfertility and infertility...

Evolution of mating system and the genetic covariance between male and female investment in Clarkia (onagraceae): selfing opposes the evolution of trade-offs.

PubMed

Mazer, Susan J; Delesalle, Véronique A; Paz, Horacio

2007-01-01

Sex allocation theory has assumed that hermaphroditic species exhibit strong genetically based trade-offs between investment in male and female function. The potential effects of mating system on the evolution of this genetic covariance, however, have not been explored. We have challenged the assumption of a ubiquitous trade-off between male and female investment by arguing that in highly self-fertilizing species, stabilizing natural selection should favor highly efficient ratios of male to female gametes. In flowering plants, the result of such selection would be similar pollen:ovule (P:O) ratios across selfing genotypes, precluding a negative genetic correlation (r(g)) between pollen and ovule production per flower. Moreover, if selfing genotypes with similar P:O ratios differ in total gametic investment per flower, a positive r(g) between pollen and ovule production would be observed. In outcrossers, by contrast, male- and female-biased flowers and genotypes may have equal fitness and coexist at evolutionary equilibrium. In the absence of strong stabilizing selection on the P:O ratio, selection on this trait will be relaxed, resulting in independence or resource-based trade-offs between male and female investment. To test this prediction, we conducted artificial selection on pollen and ovule production per flower in two sister species with contrasting mating systems. The predominantly self-fertilizing species (Clarkia exilis) consistently exhibited a significant positive r(g) between pollen and ovule production while the outcrossing species (C. unguiculata) exhibited either a trade-off or independence between these traits. Clarkia exilis also exhibited much more highly canalized gender expression than C. unguiculata. Selection on pollen and ovule production resulted in little correlated change in the P:O ratio in the selfing exilis, while dramatic changes in the P:O ratio were observed in unguiculata. To test the common prediction that floral attractiveness should be positively genetically correlated with investment in male function, we examined the response of petal area to selection on pollen and ovule production and found that petal area was not consistently genetically correlated with gender expression in either species. Our results suggest that the joint evolutionary trajectory of primary sexual traits in hermaphroditic species will be affected by their mating systems; this should be taken into account in future theoretical and comparative empirical investigations.

ENERGY-NET (Energy, Environment and Society Learning Network): Best Practices to Enhance Informal Geoscience Learning

NASA Astrophysics Data System (ADS)

Rossi, R.; Elliott, E. M.; Bain, D.; Crowley, K. J.; Steiner, M. A.; Divers, M. T.; Hopkins, K. G.; Giarratani, L.; Gilmore, M. E.

2014-12-01

While energy links all living and non-living systems, the integration of energy, the environment, and society is often not clearly represented in 9 - 12 classrooms and informal learning venues. However, objective public learning that integrates these components is essential for improving public environmental literacy. ENERGY-NET (Energy, Environment and Society Learning Network) is a National Science Foundation funded initiative that uses an Earth Systems Science framework to guide experimental learning for high school students and to improve public learning opportunities regarding the energy-environment-society nexus in a Museum setting. One of the primary objectives of the ENERGY-NET project is to develop a rich set of experimental learning activities that are presented as exhibits at the Carnegie Museum of Natural History in Pittsburgh, Pennsylvania (USA). Here we detail the evolution of the ENERGY-NET exhibit building process and the subsequent evolution of exhibit content over the past three years. While preliminary plans included the development of five "exploration stations" (i.e., traveling activity carts) per calendar year, the opportunity arose to create a single, larger topical exhibit per semester, which was assumed to have a greater impact on museum visitors. Evaluative assessments conducted to date reveal important practices to be incorporated into ongoing exhibit development: 1) Undergraduate mentors and teen exhibit developers should receive additional content training to allow richer exhibit materials. 2) The development process should be distributed over as long a time period as possible and emphasize iteration. This project can serve as a model for other collaborations between geoscience departments and museums. In particular, these practices may streamline development of public presentations and increase the effectiveness of experimental learning activities.

Polarized emission from CsPbX3 perovskite quantum dots

NASA Astrophysics Data System (ADS)

Wang, Dan; Wu, Dan; Dong, Di; Chen, Wei; Hao, Junjie; Qin, Jing; Xu, Bing; Wang, Kai; Sun, Xiaowei

2016-06-01

Compared to organic/inorganic hybrid perovskites, full inorganic perovskite quantum dots (QDs) exhibit higher stability. In this study, full inorganic CsPbX3 (X = Br, I and mixed halide systems Br/I) perovskite QDs have been synthesized and interestingly, these QDs showed highly polarized photoluminescence which is systematically studied for the first time. Furthermore, the polarization of CsPbI3 was as high as 0.36 in hexane and 0.40 as a film. The CsPbX3 perovskite QDs with high polarization properties indicate that they possess great potential for application in new generation displays with wide colour gamut and low power consumption.Compared to organic/inorganic hybrid perovskites, full inorganic perovskite quantum dots (QDs) exhibit higher stability. In this study, full inorganic CsPbX3 (X = Br, I and mixed halide systems Br/I) perovskite QDs have been synthesized and interestingly, these QDs showed highly polarized photoluminescence which is systematically studied for the first time. Furthermore, the polarization of CsPbI3 was as high as 0.36 in hexane and 0.40 as a film. The CsPbX3 perovskite QDs with high polarization properties indicate that they possess great potential for application in new generation displays with wide colour gamut and low power consumption. Electronic supplementary information (ESI) available. See DOI: 10.1039/c6nr01915c

Inkjet 3D printing of UV and thermal cure silicone elastomers for dielectric elastomer actuators

NASA Astrophysics Data System (ADS)

McCoul, David; Rosset, Samuel; Schlatter, Samuel; Shea, Herbert

2017-12-01

Dielectric elastomer actuators (DEAs) are an attractive form of electromechanical transducer, possessing high energy densities, an efficient design, mechanical compliance, high speed, and noiseless operation. They have been incorporated into a wide variety of devices, such as microfluidic systems, cell bioreactors, tunable optics, haptic displays, and actuators for soft robotics. Fabrication of DEA devices is complex, and the majority are inefficiently made by hand. 3D printing offers an automated and flexible manufacturing alternative that can fabricate complex, multi-material, integrated devices consistently and in high resolution. We present a novel additive manufacturing approach to DEA devices in which five commercially available, thermal and UV-cure DEA silicone rubber materials have been 3D printed with a drop-on-demand, piezoelectric inkjet system. Using this process, 3D structures and high-quality silicone dielectric elastomer membranes as thin as 2 μm have been printed that exhibit mechanical and actuation performance at least as good as conventionally blade-cast membranes. Printed silicone membranes exhibited maximum tensile strains of up to 727%, and DEAs with printed silicone dielectrics were actuated up to 6.1% area strain at a breakdown strength of 84 V μm-1 and also up to 130 V μm-1 at 2.4% strain. This approach holds great potential to manufacture reliable, high-performance DEA devices with high throughput.

Thermostatistically approaching living systems: Boltzmann Gibbs or nonextensive statistical mechanics?

NASA Astrophysics Data System (ADS)

Tsallis, Constantino

2006-03-01

Boltzmann-Gibbs ( BG) statistical mechanics is, since well over one century, successfully used for many nonlinear dynamical systems which, in one way or another, exhibit strong chaos. A typical case is a classical many-body short-range-interacting Hamiltonian system (e.g., the Lennard-Jones model for a real gas at moderately high temperature). Its Lyapunov spectrum (which characterizes the sensitivity to initial conditions) includes positive values. This leads to ergodicity, the stationary state being thermal equilibrium, hence standard applicability of the BG theory is verified. The situation appears to be of a different nature for various phenomena occurring in living organisms. Indeed, such systems exhibit a complexity which does not really accommodate with this standard dynamical behavior. Life appears to emerge and evolve in a kind of delicate situation, at the frontier between large order (low adaptability and long memory; typically characterized by regular dynamics, hence only nonpositive Lyapunov exponents) and large disorder (high adaptability and short memory; typically characterized by strong chaos, hence at least one positive Lyapunov exponent). Along this frontier, the maximal relevant Lyapunov exponents are either zero or close to that, characterizing what is currently referred to as weak chaos. This type of situation is shared by a great variety of similar complex phenomena in economics, linguistics, to cite but a few. BG statistical mechanics is built upon the entropy S=-k∑plnp. A generalization of this form, S=k(1-∑piq)/(q-1) (with S=S), has been proposed in 1988 as a basis for formulating what is nowadays currently called nonextensive statistical mechanics. This theory appears to be particularly adapted for nonlinear dynamical systems exhibiting, precisely, weak chaos. Here, we briefly review the theory, its dynamical foundation, its applications in a variety of disciplines (with special emphasis to living systems), and its connections with the ubiquitous scale-free networks.

Cyanate ester-nanoparticle composites as multifunctional structural capacitors

NASA Astrophysics Data System (ADS)

De Leon, J. Eliseo

An important goal of engineering is to increase the energy density of electrical energy storage devices used to deliver power onboard mobile platforms. Equally important is the goal to reduce the overall mass of the vehicles transporting these devices to achieve increased fuel and cost efficiency. One approach to meeting both these objectives is to develop multifunctional systems that serve as both energy storage and load bearing structural devices. Multifunctional devices consist of constituents that individually perform a subset of the overall desired functions. However, the synergy achieved by the combination of each constituent's characteristics allows for system-level benefits that cannot be achieved by simply optimizing the separate subsystems. We investigated multifunctional systems consisting of light weight polymer matrix and high dielectric constant fillers to achieve these objectives. The monomer of bisphenol E cyanate ester exhibited excellent processing ability because of its low room temperature viscosity. Additionally, the fully cured thermoset demonstrated excellent thermal stability, specific strength and stiffness. Fillers, including multi-walled carbon nanotubes, nanometer scale barium titanate and nanometer scale calcium copper titanate, offer high dielectric constants that raised the effective dielectric constant of the polymer matrix composite. The combination of high epsilon'and high dielectric strength produce high energy density components exhibiting increased electrical energy storage. Mechanical (load bearing) improvements of the PMCs were attributed to covalently bonded nanometer and micrometer sized filler particles, as well as the continuous glass fiber, integrated into the resin systems which increased the structural characteristics of the cured composites. Breakdown voltage tests and dynamic mechanical analysis were employed to demonstrate that precise combinations of these constituents, under the proper processing conditions, can satisfy the needs presented by the aerospace industry and military forces.

CHEMICAL RIGIDIZATION OF EXPANDABLE STRUCTURES.

DTIC Science & Technology

The objective of this program was to develop a chemical rigidization process that could be activated by an on-command mechanism and be capable of...and rigidized in the high vacuum facilities atWright-Patterson AFB, Ohio and were delivered to the Air Force. A fail-safe chemical rigidization system...have been varied from fifteen minutes to two hours. The chemical system, a vinyl-type monomer, has exhibited a sustained shelf-life, under ambient

Silicon/copper dome-patterned electrodes for high-performance hybrid supercapacitors.

PubMed

Liu, Xuyan; Jung, Hun-Gi; Kim, Sang-Ok; Choi, Ho-Suk; Lee, Sangwha; Moon, Jun Hyuk; Lee, Joong Kee

2013-12-02

This study proposes a method for manufacturing high-performance electrode materials in which controlling the shape of the current collector and electrode material for a Li-ion capacitor (LIC). In particular, the proposed LIC manufacturing method maintains the high voltage of a cell by using a microdome-patterned electrode material, allowing for reversible reactions between the Li-ion and the active material for an extended period of time. As a result, the LICs exhibit initial capacities of approximately 42 F g⁻¹, even at 60 A g⁻¹. The LICs also exhibit good cycle performance up to approximately 15,000 cycles. In addition, these advancements allow for a considerably higher energy density than other existing capacitor systems. The energy density of the proposed LICs is approximately nine, two, and 1.5 times higher than those of the electrochemical double layer capacitor (EDLC), AC/LiMn₂O₄ hybrid capacitor, and intrinsic Si/AC LIC, respectively.

Silicon/copper dome-patterned electrodes for high-performance hybrid supercapacitors

NASA Astrophysics Data System (ADS)

Liu, Xuyan; Jung, Hun-Gi; Kim, Sang-Ok; Choi, Ho-Suk; Lee, Sangwha; Moon, Jun Hyuk; Lee, Joong Kee

2013-12-01

This study proposes a method for manufacturing high-performance electrode materials in which controlling the shape of the current collector and electrode material for a Li-ion capacitor (LIC). In particular, the proposed LIC manufacturing method maintains the high voltage of a cell by using a microdome-patterned electrode material, allowing for reversible reactions between the Li-ion and the active material for an extended period of time. As a result, the LICs exhibit initial capacities of approximately 42 F g-1, even at 60 A g-1. The LICs also exhibit good cycle performance up to approximately 15,000 cycles. In addition, these advancements allow for a considerably higher energy density than other existing capacitor systems. The energy density of the proposed LICs is approximately nine, two, and 1.5 times higher than those of the electrochemical double layer capacitor (EDLC), AC/LiMn2O4 hybrid capacitor, and intrinsic Si/AC LIC, respectively.

H3PO4 solution hydrothermal carbonization combined with KOH activation to prepare argy wormwood-based porous carbon for high-performance supercapacitors

NASA Astrophysics Data System (ADS)

Dai, Changchao; Wan, Jiafeng; Yang, Juan; Qu, Shanshan; Jin, Tieyu; Ma, Fangwei; Shao, Jinqiu

2018-06-01

In this work, argy wormwood-based porous carbon electrode materials for high-performance supercapacitors are prepared through H3PO4 solution hydrothermal carbonization and subsequent KOH activation. The obtained carbon has a specific surface area (SSA) of 927 m2 g-1, a total pore volume of 0.56 cm3 g-1, and a high oxygen (9.38%) content. In three-electrode system, it exhibits specific capacitance of 344 F g-1 at 1 A g-1. Moreover, the symmetric supercapacitor shows an excellent rate capability of 87% retention from 1 A g-1 to 10 A g-1, and a good cycling performance with 91.6% retention over 5000 cycles in 6 M KOH. Therefore, the sample activated by H3PO4 & KOH exhibits an excellent future in energy storage.

Resonant tunnelling in a quantum oxide superlattice

DOE PAGES

Choi, Woo Seok; Lee, Sang A.; You, Jeong Ho; ...

2015-06-24

Resonant tunneling is a quantum mechanical process that has long been attracting both scientific and technological attention owing to its intriguing underlying physics and unique applications for high-speed electronics. The materials system exhibiting resonant tunneling, however, has been largely limited to the conventional semiconductors, partially due to their excellent crystalline quality. Here we show that a deliberately designed transition metal oxide superlattice exhibits a resonant tunneling behaviour with a clear negative differential resistance. The tunneling occurred through an atomically thin, lanthanum δ- doped SrTiO 3 layer, and the negative differential resistance was realized on top of the bi-polar resistance switchingmore » typically observed for perovskite oxide junctions. This combined process resulted in an extremely large resistance ratio (~10 5) between the high and low resistance states. Lastly, the unprecedentedly large control found in atomically thin δ-doped oxide superlattices can open a door to novel oxide-based high-frequency logic devices.« less

Formation of Multi-Layer Structures in Bi3Pb7 Intermetallic Compounds under an Ultra-High Gravitational Field

NASA Astrophysics Data System (ADS)

Mashimo, T.; Iguchi, Y.; Bagum, R.; Sano, T.; Sakata, O.; Ono, M.; Okayasu, S.

2008-02-01

Ultra-high gravitational field (Mega-gravity field) can promote sedimentation of atoms (diffusion) even in solids, and is expected to form a compositionally-graded structure and/or nonequilibrium phase in multi-component condensed matter. We had achieved sedimentation of substitutional solute atoms in miscible systems (Bi-Sb, In-Pb, etc.). In this study, a mega-gravity experiment at high temperature was performed on a thin-plate sample (0.7 mm in thickness) of the intermetallic compound Bi3Pb7. A visible four-layer structure was produced, which exhibited different microscopic structures. In the lowest-gravity region layer, Bi phase appeared. In the mid layers, a compositionally-graded structure was formed, with differences observed in the powder X-ray diffraction patterns. Such a multi-layer structure is expected to exhibit unique physical properties such as superconductivity.

Comfortable, high-efficiency heat pump with desiccant-coated, water-sorbing heat exchangers

NASA Astrophysics Data System (ADS)

Tu, Y. D.; Wang, R. Z.; Ge, T. S.; Zheng, X.

2017-01-01

Comfortable, efficient, and affordable heating, ventilation, and air conditioning systems in buildings are highly desirable due to the demands of energy efficiency and environmental friendliness. Traditional vapor-compression air conditioners exhibit a lower coefficient of performance (COP) (typically 2.8-3.8) owing to the cooling-based dehumidification methods that handle both sensible and latent loads together. Temperature- and humidity-independent control or desiccant systems have been proposed to overcome these challenges; however, the COP of current desiccant systems is quite small and additional heat sources are usually needed. Here, we report on a desiccant-enhanced, direct expansion heat pump based on a water-sorbing heat exchanger with a desiccant coating that exhibits an ultrahigh COP value of more than 7 without sacrificing any comfort or compactness. The pump’s efficiency is doubled compared to that of pumps currently used in conventional room air conditioners, which is a revolutionary HVAC breakthrough. Our proposed water-sorbing heat exchanger can independently handle sensible and latent loads at the same time. The desiccants adsorb moisture almost isothermally and can be regenerated by condensation heat. This new approach opens up the possibility of achieving ultrahigh efficiency for a broad range of temperature- and humidity-control applications.

Comfortable, high-efficiency heat pump with desiccant-coated, water-sorbing heat exchangers.

PubMed

Tu, Y D; Wang, R Z; Ge, T S; Zheng, X

2017-01-12

Comfortable, efficient, and affordable heating, ventilation, and air conditioning systems in buildings are highly desirable due to the demands of energy efficiency and environmental friendliness. Traditional vapor-compression air conditioners exhibit a lower coefficient of performance (COP) (typically 2.8-3.8) owing to the cooling-based dehumidification methods that handle both sensible and latent loads together. Temperature- and humidity-independent control or desiccant systems have been proposed to overcome these challenges; however, the COP of current desiccant systems is quite small and additional heat sources are usually needed. Here, we report on a desiccant-enhanced, direct expansion heat pump based on a water-sorbing heat exchanger with a desiccant coating that exhibits an ultrahigh COP value of more than 7 without sacrificing any comfort or compactness. The pump's efficiency is doubled compared to that of pumps currently used in conventional room air conditioners, which is a revolutionary HVAC breakthrough. Our proposed water-sorbing heat exchanger can independently handle sensible and latent loads at the same time. The desiccants adsorb moisture almost isothermally and can be regenerated by condensation heat. This new approach opens up the possibility of achieving ultrahigh efficiency for a broad range of temperature- and humidity-control applications.

B-52 stability augmentation system reliability

NASA Technical Reports Server (NTRS)

Bowling, T. C.; Key, L. W.

1976-01-01

The B-52 SAS (Stability Augmentation System) was developed and retrofitted to nearly 300 aircraft. It actively controls B-52 structural bending, provides improved yaw and pitch damping through sensors and electronic control channels, and puts complete reliance on hydraulic control power for rudder and elevators. The system has experienced over 300,000 flight hours and has exhibited service reliability comparable to the results of the reliability test program. Development experience points out numerous lessons with potential application in the mechanization and development of advanced technology control systems of high reliability.

STAR FORMATION AND SUPERCLUSTER ENVIRONMENT OF 107 NEARBY GALAXY CLUSTERS

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

Cohen, Seth A.; Hickox, Ryan C.; Wegner, Gary A.

We analyze the relationship between star formation (SF), substructure, and supercluster environment in a sample of 107 nearby galaxy clusters using data from the Sloan Digital Sky Survey. Previous works have investigated the relationships between SF and cluster substructure, and cluster substructure and supercluster environment, but definitive conclusions relating all three of these variables has remained elusive. We find an inverse relationship between cluster SF fraction ( f {sub SF}) and supercluster environment density, calculated using the Galaxy luminosity density field at a smoothing length of 8 h {sup −1} Mpc (D8). The slope of f {sub SF} versus D8more » is −0.008 ± 0.002. The f {sub SF} of clusters located in low-density large-scale environments, 0.244 ± 0.011, is higher than for clusters located in high-density supercluster cores, 0.202 ± 0.014. We also divide superclusters, according to their morphology, into filament- and spider-type systems. The inverse relationship between cluster f {sub SF} and large-scale density is dominated by filament- rather than spider-type superclusters. In high-density cores of superclusters, we find a higher f {sub SF} in spider-type superclusters, 0.229 ± 0.016, than in filament-type superclusters, 0.166 ± 0.019. Using principal component analysis, we confirm these results and the direct correlation between cluster substructure and SF. These results indicate that cluster SF is affected by both the dynamical age of the cluster (younger systems exhibit higher amounts of SF); the large-scale density of the supercluster environment (high-density core regions exhibit lower amounts of SF); and supercluster morphology (spider-type superclusters exhibit higher amounts of SF at high densities).« less

DNA methylation in inflammatory genes among children with obstructive sleep apnea.

PubMed

Kim, Jinkwan; Bhattacharjee, Rakesh; Khalyfa, Abdelnaby; Kheirandish-Gozal, Leila; Capdevila, Oscar Sans; Wang, Yang; Gozal, David

2012-02-01

Pediatric obstructive sleep apnea (OSA) leads to multiple end-organ morbidities that are mediated by the cumulative burden of oxidative stress and inflammation. Because not all children with OSA exhibit increased systemic inflammation, genetic and environmental factors may be affecting patterns of DNA methylation in genes subserving inflammatory functions. DNA from matched children with OSA with and without high levels of high-sensitivity C-reactive protein (hsCRP) were assessed for DNA methylation levels of 24 inflammatory-related genes. Primer-based polymerase chain reaction assays in a case-control setting involving 47 OSA cases and 31 control subjects were conducted to confirm the findings; hsCRP and myeloid-related protein (MRP) 8/14 levels were also assayed. Forkhead box P3 (FOXP3) and interferon regulatory factor 1 (IRF1) showed higher methylation in six children with OSA and high hsCRP levels compared with matched children with OSA and low hsCRP levels (P < 0.05). In the case-control cohort, children with OSA and high CRP levels had higher log FOXP3 DNA methylation levels compared with children with OSA and low CRP levels and control subjects. IRF1 did not exhibit significant differences. FOXP3 DNA methylation levels correlated with hsCRP and MRP 8/14 levels and with apnea-hypopnea index (AHI), BMI z score, and apolipoprotein B levels. A stepwise multiple regression model showed that AHI was independently associated with FOXP3 DNA methylation levels (P < 0.03). The FOXP3 gene, which regulates expression of T regulatory lymphocytes, is more likely to display increased methylation among children with OSA who exhibit increased systemic inflammatory responses. Thus, epigenetic modifications may constitute an important determinant of inflammatory phenotype in OSA, and FOXP3 DNA methylation levels may provide a potential biomarker for end-organ vulnerability.

Compassionate Love Buffers Stress-Reactive Mothers from Fight-or-Flight Parenting

ERIC Educational Resources Information Center

Miller, Jonas G.; Kahle, Sarah; Lopez, Monica; Hastings, Paul D.

2015-01-01

The links among mothers' compassionate love for their child, autonomic nervous system activity, and parenting behavior during less and more challenging mother-child interactions were examined. Mothers expressed and reported less negative affect when they exhibited autonomic patterns of increased parasympathetic dominance (high parasympathetic…

Comparative Data Mining Analysis for Information Retrieval of MODIS Images: Monitoring Lake Turbidity Changes at Lake Okeechobee, Florida

EPA Science Inventory

In the remote sensing field, a frequently recurring question is: Which computational intelligence or data mining algorithms are most suitable for the retrieval of essential information given that most natural systems exhibit very high non-linearity. Among potential candidates mig...

Oral Histories of Four Urban Youth Affected by Disproportionality in Special Education

ERIC Educational Resources Information Center

Wright, Shalene R.

2012-01-01

This study uncovered some experiences and perspectives of four students of color during their educational journey through K-12 public schools as students identified with high incidence disabilities in school systems that exhibited ethnic disproportionality in special education. The participants reflected on their experiences to provide detailed…

Aspects of Supercritical Turbulence: Direct Numerical Simulation of O2/H2 and C7H16/N2 Temporal Mixing Layers

NASA Technical Reports Server (NTRS)

Bellan, J.; Okongo, N. A.; Harstad, K. G.; Hutt, John (Technical Monitor)

2002-01-01

Results from Direct Numerical Simulations of temporal, supercritical mixing layers for two species systems are analyzed to elucidate species-specific turbulence aspects. The two species systems, O2/H2 and C7HG16/N2, have different thermodynamic characteristics; thus, although the simulations are performed at similar reduced pressure (ratio of the pressure to the critical pressure), the former system is dose to mixture ideality and has a relatively high solubility with respect to the latter, which exhibits strong departures from mixture ideality Due to the specified, smaller initial density stratification, the C7H16/N2 layers display higher growth and increased global molecular mixing as well as larger turbulence levels. However, smaller density gradients at the transitional state for the O2/H2 system indicate that on a local basis, the layer exhibits an enhanced mixing, this being attributed to the increased solubility and to mixture ideality. These thermodynamic features are shown to affect the irreversible entropy production (i.e. the dissipation), which is larger for the O2/H2 layer and is primarily concentrated in high density-gradient magnitude regions that are distortions of the initial density stratification boundary. In contrast, the regions of largest dissipation in the C7H16/N2 layer are located in high density-gradient magnitude regions resulting from the mixing of the two fluids.

2007 Global Demilitarization Symposium and Exhibition

DTIC Science & Technology

2007-05-17

system! Defines reactive properties ! www.biorex.se Heavy metals • Water soluble • Easily spread • Elements • Not degradable • Hazardous • In high or low...Activated sludge Oat by-products Juniper fibre Sawdust Agro-based fibres Seaweed Grape stalk fibres Marine algae Husk of black gram www.biorex.se Sorbent...Description Reactor Illustration 18 inch diameter reactor 120 inches high Single diameter throughout entire reactor length 19 resistance heaters Alloy 600

From Mahan excitons to Landau levels at high magnetic fields: 2DFT spectroscopy reveals hidden quantum correlations (Conference Presentation)

NASA Astrophysics Data System (ADS)

Karaiskaj, Denis

2017-02-01

Two-dimensional electron gases have been the subject of research for decades. Modulation doped GaAs quantum wells in the absence of magnetic fields exhibit interesting many-body physics such as the Fermi edge singularity or Mahan exciton and can be regarded as a collective excitation of the system. Under high magnetic fields Landau levels form which have been studied using transport and optical measurements. Nonlinear coherent two-dimensional Fourier transform (2DFT) spectroscopy however provides new insights into these systems. We present the 2DFT spectra of Mahan Excitons associated with the heavy-hole and light-hole resonances observed in a modulation doped GaAs/AlGaAs single quantum well [1]. These resonances are observed to be strongly coupled through many-body interactions. The 2DFT spectra were measured using co-linear, cross-linear, and co-circular polarizations and reveal striking differences. Furthermore, 2DFT spectra at high magnetic fields performed at the National High Magnetic Field Lab (NHMFL) in Tallahassee, Florida will be discussed. The spectra exhibit new features and peculiar line shapes suggesting interesting underlying physics. [1] J. Paul, C. E. Stevens, C. Liu, P. Dey, C. McIntyre, V. Turkowski, J. L. Reno, D. J. Hilton, and D. Karaiskaj, Phys. Rev. Lett.116, 157401 (2016).

Accommodating High Transformation Strains in Battery Electrodes via the Formation of Nanoscale Intermediate Phases: Operando Investigation of Olivine NaFePO 4 [Accommodation of High Transformation Strain in Battery Electrodes via Formation of Nanoscale Intermediate Phases: Operando Structure Investigation of Olivine Sodium Iron Phosphate

DOE PAGES

Xiang, Kai; Xing, Wenting; Ravnsbaek, Dorthe B.; ...

2017-02-21

Virtually all intercalation compounds used as battery electrodes exhibit significant changes in unit cell volume during use. Na xFePO 4 (0 < x < 1, NFP) olivine, of interest as a cathode for sodium-ion batteries, is a model for topotactic, high strain systems as it exhibits one of the largest discontinuous volume changes (~17% by volume) during its first-order transition between two otherwise isostructural phases. Using synchrotron radiation powder X-ray diffraction (PXD) and pair distribution function (PDF) analysis, we discover a new strain-accommodation mechanism wherein a third, <10 nm scale nanocrystalline phase forms to buffer the large lattice mismatch betweenmore » primary phases. The new phase has a and b lattice parameters matching one crystalline endmember phase and c lattice parameter matching the other, and is not detectable by powder diffraction alone. Finally, we suggest that this strain-accommodation mechanism may apply to systems with large transformation strains but in which true “amorphization” does not occur.« less

Fast photoresponse and high detectivity in copper indium selenide (CuIn7Se11) phototransistors

NASA Astrophysics Data System (ADS)

Ghosh, Sujoy; Patil, Prasanna D.; Wasala, Milinda; Lei, Sidong; Nolander, Andrew; Sivakumar, Pooplasingam; Vajtai, Robert; Ajayan, Pulickel; Talapatra, Saikat

2018-03-01

The fast and sensitive detection of light can lead to a variety of optoelectronics and/or photonic-based applications in fields ranging from fast optical switching devices to health and environmental monitoring systems. Although several systems based on organic and inorganic materials show high sensitivity to visible light, in general they suffer from slow response times. Here we show that phototransistors fabricated using multilayers of CuIn7Se11 exhibit response times of ~ tens of µs with responsivity (R) values  >  10 AW-1 and with external quantum efficiencies reaching beyond 103 % when excited with a 658 nm wavelength laser. These devices also show high specific detectivity (D *) values of ~1012 Jones. The responsivity and detectivity exhibited by these phototransistors are at least an order of magnitude better than commercially available conventional Si-based photodetectors, coupled with response times that are orders of magnitude better than several other families of layered materials investigated so far. The properties of the CuIn7Se11 phototransistor can be further tuned and enhanced by applying a back-gate voltage. Our investigations indicate that such layered ternary compounds can potentially be used as components in opto-electronics-related applications.

Accommodating High Transformation Strains in Battery Electrodes via the Formation of Nanoscale Intermediate Phases: Operando Investigation of Olivine NaFePO 4 [Accommodation of High Transformation Strain in Battery Electrodes via Formation of Nanoscale Intermediate Phases: Operando Structure Investigation of Olivine Sodium Iron Phosphate

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

Xiang, Kai; Xing, Wenting; Ravnsbaek, Dorthe B.

Virtually all intercalation compounds used as battery electrodes exhibit significant changes in unit cell volume during use. Na xFePO 4 (0 < x < 1, NFP) olivine, of interest as a cathode for sodium-ion batteries, is a model for topotactic, high strain systems as it exhibits one of the largest discontinuous volume changes (~17% by volume) during its first-order transition between two otherwise isostructural phases. Using synchrotron radiation powder X-ray diffraction (PXD) and pair distribution function (PDF) analysis, we discover a new strain-accommodation mechanism wherein a third, <10 nm scale nanocrystalline phase forms to buffer the large lattice mismatch betweenmore » primary phases. The new phase has a and b lattice parameters matching one crystalline endmember phase and c lattice parameter matching the other, and is not detectable by powder diffraction alone. Finally, we suggest that this strain-accommodation mechanism may apply to systems with large transformation strains but in which true “amorphization” does not occur.« less

Asymmetry and basic pathways in sleep-stage transitions

NASA Astrophysics Data System (ADS)

Lo, Chung-Chuan; Bartsch, Ronny P.; Ivanov, Plamen Ch.

2013-04-01

We study dynamical aspects of sleep micro-architecture. We find that sleep dynamics exhibits a high degree of asymmetry, and that the entire class of sleep-stage transition pathways underlying the complexity of sleep dynamics throughout the night can be characterized by two independent asymmetric transition paths. These basic pathways remain stable under sleep disorders, even though the degree of asymmetry is significantly reduced. Our findings demonstrate an intriguing temporal organization in sleep micro-architecture at short time scales that is typical for physical systems exhibiting self-organized criticality (SOC), and indicates nonequilibrium critical dynamics in brain activity during sleep.

Evaluation of high temperature structural adhesives for extended service

NASA Technical Reports Server (NTRS)

Hendricks, C. L.; Hill, S. G.

1984-01-01

High temperature stable adhesive systems were evaluated for potential Supersonic Cruise Research (SCR) vehicle applications. The program was divided into two major phases: Phase I 'Adhesive Screening' evaluated eleven selected polyimide (PI) and polyphenylquinoxaline (PPQ) adhesive resins using eight different titanium (6Al-4V) adherend surface preparations; Phase II 'Adhesive Optimization and Characterization' extensively evaluated two adhesive systems, selected from Phase I studies, for chemical characterization and environmental durability. The adhesive systems which exhibited superior thermal and environmental bond properties were LARC-TPI polyimide and polyphenylquinoxaline both developed at NASA Langley. The latter adhesive system did develop bond failures at extended thermal aging due primarily to incompatibility between the surface preparation and the polymer. However, this study did demonstrate that suitable adhesive systems are available for extended supersonic cruise vehicle design applications.

Noncovalent interaction-assisted drug delivery system with highly efficient uptake and release of paclitaxel for anticancer therapy.

PubMed

Wei, Yuping; Ma, Liang; Zhang, Liang; Xu, Xia

2017-01-01

An effective drug delivery system requires efficient drug uptake and release inside cancer cells. Here, we report a novel drug delivery system, in which paclitaxel (PTX) interacts with a novel cell penetrating peptide (CPP) through noncovalent interaction designed based on molecular simulations. This CPP/PTX complex confers high efficiency in delivering PTX into cancer cells not by endocytosis but by an energy-independent pathway. Once inside cells, the noncovalent interaction between PTX and the CPP may allow fast release of PTX within cells due to the direct translocation of CPP/PTX. This drug delivery system exhibits strong capacity for inhibition of tumor growth and offers a new avenue for the development of advanced drug delivery systems for anticancer therapy.

A multifunctional metal-organic framework based tumor targeting drug delivery system for cancer therapy

NASA Astrophysics Data System (ADS)

Wang, Xiao-Gang; Dong, Zhi-Yue; Cheng, Hong; Wan, Shuang-Shuang; Chen, Wei-Hai; Zou, Mei-Zhen; Huo, Jia-Wei; Deng, He-Xiang; Zhang, Xian-Zheng

2015-09-01

Drug delivery systems (DDSs) with biocompatibility and precise drug delivery are eagerly needed to overcome the paradox in chemotherapy that high drug doses are required to compensate for the poor biodistribution of drugs with frequent dose-related side effects. In this work, we reported a metal-organic framework (MOF) based tumor targeting DDS developed by a one-pot, and organic solvent-free ``green'' post-synthetic surface modification procedure, starting from the nanoscale MOF MIL-101. Owing to the multifunctional surface coating, premature drug release from this DDS was prevented. Due to the pH responsive benzoic imine bond and the redox responsive disulfide bond at the modified surface, this DDS exhibited tumor acid environment enhanced cellular uptake and intracellular reducing environment triggered drug release. In vitro and in vivo results showed that DOX loaded into this DDS exhibited effective cancer cell inhibition with much reduced side effects.Drug delivery systems (DDSs) with biocompatibility and precise drug delivery are eagerly needed to overcome the paradox in chemotherapy that high drug doses are required to compensate for the poor biodistribution of drugs with frequent dose-related side effects. In this work, we reported a metal-organic framework (MOF) based tumor targeting DDS developed by a one-pot, and organic solvent-free ``green'' post-synthetic surface modification procedure, starting from the nanoscale MOF MIL-101. Owing to the multifunctional surface coating, premature drug release from this DDS was prevented. Due to the pH responsive benzoic imine bond and the redox responsive disulfide bond at the modified surface, this DDS exhibited tumor acid environment enhanced cellular uptake and intracellular reducing environment triggered drug release. In vitro and in vivo results showed that DOX loaded into this DDS exhibited effective cancer cell inhibition with much reduced side effects. Electronic supplementary information (ESI) available: Synthesis procedure, 1HNMR, ESI-MS and additional data. See DOI: 10.1039/c5nr04045k

High pressure mechanical seal

NASA Technical Reports Server (NTRS)

Babel, Henry W. (Inventor); Anderson, Raymond H. (Inventor)

1996-01-01

A relatively impervious mechanical seal is formed between the outer surface of a tube and the inside surface of a mechanical fitting of a high pressure fluid or hydraulic system by applying a very thin soft metal layer onto the outer surface of the hard metal tube and/or inner surface of the hard metal fitting. The thickness of such thin metal layer is independent of the size of the tube and/or fittings. Many metals and alloys of those metals exhibit the requisite softness, including silver, gold, tin, platinum, indium, rhodium and cadmium. Suitably, the coating is about 0.0025 millimeters (0.10 mils) in thickness. After compression, the tube and fitting combination exhibits very low leak rates on the order or 10.sup.-8 cubic centimeters per second or less as measured using the Helium leak test.

Efficacy of forming biofilms by Pseudomonas migulae AN-1 toward in situ bioremediation of aniline-contaminated aquifer by groundwater circulation wells.

PubMed

Zhao, Yongsheng; Qu, Dan; Zhou, Rui; Yang, Shuai; Ren, Hejun

2016-06-01

The formation and activity of aniline-degrading biofilms developed by the psychrotrophic Pseudomonas migulae AN-1 were studied for the in situ remediation of contaminated aquifer using in-well bioreactor of groundwater circulating wells (GCWs). Biofilms grown in mineral salt medium with aniline exhibited tolerance to high concentrations of aniline. In aniline degradation rate, AN-1 biofilms exhibited slight differences compared with planktonic cells. The effectiveness and bio-implication of AN-1 biofilms in GCWs were investigated to treat aniline-contaminated aquifer. The results demonstrate that AN-1 biofilms survived the GCWs treatment process with high aniline-degrading efficiency. This system provides a novel environmentally friendly technology for the in situ bioremediation of low-volatile contaminants.

HIV-risk characteristics in community corrections.

PubMed

Clark, C Brendan; McCullumsmith, Cheryl B; Waesche, Matthew C; Islam, M Aminul; Francis, Reginald; Cropsey, Karen L

2013-01-01

Individuals in the criminal justice system engage in behaviors that put them at high risk for HIV. This study sought to identify characteristics of individuals who are under community corrections supervision (eg, probation) and at risk for HIV. Approximately 25,000 individuals under community corrections supervision were assessed for HIV risk, and 5059 participants were deemed high-risk or no-risk. Of those, 1519 exhibited high sexual-risk (SR) behaviors, 203 exhibited injection drug risk (IVR), 957 exhibited both types of risk (SIVR), and 2380 exhibited no risk. Sociodemographic characteristics and drug of choice were then examined using univariate and binary logistic regression. Having a history of sexual abuse, not having insurance, and selecting any drug of choice were associated with all forms of HIV risk. However, the effect sizes associated with the various drugs of choice varied significantly by group. Aside from those common risk factors, very different patterns emerged. Female gender was a risk factor for the SR group but was less likely to be associated with IVR. Younger age was associated with SR, whereas older age was associated with IVR. Black race was a risk factor for SR but had a negative association with IVR and SIVR. Living in a shelter, living with relatives/friends, and being unemployed were all risk factors for IVR but were protective factors for SR. Distinct sociodemographic and substance use characteristics were associated with sexual versus injection drug use risk for individuals under community corrections supervision who were at risk for HIV. Information from this study could help identify high-risk individuals and allow tailoring of interventions.

Geospatial drivers of the groundwater δ18O isoscape in a temperate maritime climate (Republic of Ireland)

NASA Astrophysics Data System (ADS)

Regan, S.; Goodhue, R.; Naughton, O.; Hynds, P.

2017-11-01

In recent years, the concept of ;isoscapes; has been used to describe spatiotemporal stable isotope distributions within natural environments including groundwater systems at multiple scales. This study presents an updated groundwater δ18O isoscape for the Republic of Ireland and describes the climatic and geological drivers influencing 18O composition. In all, 142 geographically and geologically representative groundwater installations were sampled and analysed, in addition to 35 samples from six nested boreholes. Geospatially, Irish groundwater exhibits high δ18O values in southern and western coastal regions, becoming progressively depleted inland before reaching lowest measured values along the eastern coast, equating to a national groundwater δ18O profile range of approximately 3‰. Groundwater δ18O composition is primarily driven by location with respect to orographically influenced rainfall deposition and annual precipitation volume, with a bias towards winter recharge. Results also demonstrate that local/regional (hydro)geological setting exerts a secondary influence on δ18O composition via infiltration and recharge mechanisms. ;Flashy; groundwater systems (e.g. karst limestones) are more likely to exhibit seasonal groundwater δ18O patterns, whereas low productivity systems with high residence times (e.g. granites), tend to display a dampened composition to groundwater recharge and exhibit more temporally constant δ18O values. The derived δ18O isoscape enhances current understanding of what is a geologically distinct groundwater setting, whilst also potentially serving as a δ18O ;sentinel; for continental Europe, with respect to both groundwater and precipitation, due to Ireland's geographic location.

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

Chen, Zhe; Cao, Minhua, E-mail: caomh@bit.edu.cn; Key Laboratory of Cluster Science, Ministry of Education of China, Department of Chemistry, Beijing Institute of Technology, Beijing 100081

Research highlights: {yields} Novel Bi{sub 2}S{sub 3} hierarchical nanostructures self-assembled by nanorods are successfully synthesized in mild benzyl alcohol system under hydrothermal conditions. {yields} The hierarchical nanostructures exhibit a flower-like shape. {yields} PVP plays an important role for the formation of the hierarchical nanostructures. {yields} Bi{sub 2}S{sub 3} film prepared from the flower-like hierarchical nanostructures exhibits good hydrophobic properties. -- Abstract: Novel Bi{sub 2}S{sub 3} hierarchical nanostructures self-assembled by nanorods are successfully synthesized in mild benzyl alcohol system under hydrothermal conditions. The hierarchical nanostructures exhibit a flower-like shape. X-ray diffraction (XRD), X-ray photoelectron spectra (XPS), scanning electron microscopy (SEM), transmissionmore » electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM), and selected area electron diffraction (SAED) were used to characterize the as-synthesized samples. Meanwhile, the effect of various experimental parameters including the concentration of reagents and reaction time on final product has been investigated. In our experiment, PVP plays an important role for the formation of the hierarchical nanostructures and the possible mechanism was proposed. In addition, Bi{sub 2}S{sub 3} film prepared from the flower-like hierarchical nanostructures exhibits good hydrophobic properties, which may bring nontrivial functionalities and may have some promising applications in the future.« less

Synthesis of high density aviation fuel with cyclopentanol derived from lignocellulose

PubMed Central

Sheng, Xueru; Li, Ning; Li, Guangyi; Wang, Wentao; Yang, Jinfan; Cong, Yu; Wang, Aiqin; Wang, Xiaodong; Zhang, Tao

2015-01-01

For the first time, renewable high density aviation fuels were synthesized at high overall yield (95.6%) by the Guerbet reaction of cyclopentanol which can be derived from lignocellulose, followed by the hydrodeoxygenation (HDO). The solvent-free Guerbet reaction of cyclopentanol was carried out under the co-catalysis of solid bases and Raney metals. Among the investigated catalyst systems, the combinations of magnesium-aluminium hydrotalcite (MgAl-HT) and Raney Ni (or Raney Co) exhibited the best performances. Over them, high carbon yield (96.7%) of C10 and C15 oxygenates was achieved. The Guerbet reaction products were further hydrodeoxygenated to bi(cyclopentane) and tri(cyclopentane) over a series of Ni catalysts. These alkanes have high densities (0.86 g mL−1 and 0.91 g mL−1) and can be used as high density aviation fuels or additives to bio-jet fuel. Among the investigated HDO catalysts, the 35 wt.% Ni-SiO2-DP prepared by deposition-precipitation method exhibited the highest activity. PMID:25826744

High voltage testing for the Majorana Demonstrator

DOE PAGES

Abgrall, N.; Arnquist, I. J.; Avignone, III, F. T.; ...

2016-04-04

The Majorana Collaboration is constructing the Majorana Demonstrator, an ultra-low background, 44-kg modular high-purity Ge (HPGe) detector array to search for neutrinoless double-beta decay in 76Ge. The phenomenon of surface micro-discharge induced by high-voltage has been studied in the context of the Majorana Demonstrator. This effect can damage the front-end electronics or mimic detector signals. To ensure the correct performance, every high-voltage cable and feedthrough must be capable of supplying HPGe detector operating voltages as high as 5 kV without exhibiting discharge. R&D measurements were carried out to understand the testing system and determine the optimum design configuration of themore » high-voltage path, including different improvements of the cable layout and feedthrough flange model selection. Every cable and feedthrough to be used at the Majorana Demonstrator was characterized and the micro-discharge effects during the Majorana Demonstrator commissioning phase were studied. Furthermore, a stable configuration has been achieved, and the cables and connectors can supply HPGe detector operating voltages without exhibiting discharge.« less

High voltage testing for the Majorana Demonstrator

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

Abgrall, N.; Arnquist, Isaac J.; Avignone, F. T.

2016-07-01

The Majorana Collaboration is constructing theMajorana Demonstrator, an ultra-low background, 44-kg modular high-purity Ge (HPGe) detector array to search for neutrinoless double-beta decay in 76Ge. The phenomenon of surface micro-discharge induced by high-voltage has been studied in the context of theMajorana Demonstrator. This effect can damage the front-end electronics or mimic detector signals. To ensure the correct performance, every high-voltage cable and feedthrough must be capable of supplying HPGe detector operating voltages as high as 5 kV without exhibiting discharge. R&D measurements were carried out to understand the testing system and determine the optimum design configuration of the high-voltage path,more » including different improvements of the cable layout and feedthrough flange model selection. Every cable and feedthrough to be used at the Majorana Demonstrator was characterized and the micro-discharge effects during theMajorana Demonstrator commissioning phase were studied. A stable configuration has been achieved, and the cables and connectors can supply HPGe detector operating voltages without exhibiting discharge.« less

Thermocouples of tantalum and rhenium alloys for more stable vacuum-high temperature performance

NASA Technical Reports Server (NTRS)

Morris, J. F. (Inventor)

1977-01-01

Thermocouples of the present invention provide stability and performance reliability in systems involving high temperatures and vacuums by employing a bimetallic thermocouple sensor wherein each metal of the sensor is selected from a group of metals comprising tantalum and rhenium and alloys containing only those two metals. The tantalum, rhenium thermocouple sensor alloys provide bare metal thermocouple sensors having advantageous vapor pressure compatibilities and performance characteristics. The compatibility and physical characteristics of the thermocouple sensor alloys of the present invention result in improved emf, temperature properties and thermocouple hot junction performance. The thermocouples formed of the tantalum, rhenium alloys exhibit reliability and performance stability in systems involving high temperatures and vacuums and are adaptable to space propulsion and power systems and nuclear environments.

Laser dye DCM: CW, synchronously pumped, cavity pumped and single-frequency performance

NASA Astrophysics Data System (ADS)

Marason, E. G.

1981-04-01

Laser dye DCM exhibits a tuning range of 605 to 725 nm with a lasing efficiency as high as 34% when pumped by the 488 nm line of the argon ion laser, placing it among the most efficient and broadly tunable dyes known. Performance of the dye is characterized for four laser systems: 1) continuous wave, 2) synchronously pumped (SP), 3) cavity dumped synchrompously pumped (SPCD) and 4) single-frequency ring dye laser. Pulse peak powers were as high as 520 W and 2.8 kW for SP and SPCD systems respectively.

77 FR 31909 - Culturally Significant Objects Imported for Exhibition

Federal Register 2010, 2011, 2012, 2013, 2014

2012-05-30

... exhibition ``50th Anniversary Remembrance of the Tragedy at Orly,'' imported from abroad by the High Museum of Art for temporary exhibition within the United States, is of cultural significance. The object is... exhibition or display of the exhibit object at the High Museum of Art in Atlanta, Georgia from on or about...

The Effect of Molecular Weight on the Composite Properties of Cured Phenylethynyl Terminated Imide Oligomers

NASA Technical Reports Server (NTRS)

Smith, J. G., Jr.; Connell, J. W.; Hergenrother, P. M.

1997-01-01

As part of a program to develop high temperature/high performance structural resins for aeronautical applications, imide oligomers containing terminal phenylethynyl groups with calculated number average molecular weights of 1250, 2500 and 5000 g/mol were prepared, characterized, and evaluated as adhesives and composite matrix resins. The goal of this work was to develop resin systems that are processable using conventional processing equipment into void free composites that exhibit high mechanical properties with long term high temperature durability, and are not affected by exposure to common aircraft fluids. The imide oligomers containing terminal phenylethynyl groups were fabricated into titanium adhesive specimens and IM-7 carbon fiber laminates under 0.1 - 1.4 MPa for 1 hr at 350-371 C. The lower molecular weight oligomers exhibited higher cured Tg, better processability, and better retention of mechanical properties at elevated temperature without significantly sacrificing toughness or damage tolerance than the higher molecular weight oligomer. The neat resin, adhesive and composite properties of the cured polymers will be presented.

Suzaku Observation of Two Ultraluminous X-ray Sources in NGC 1313

NASA Technical Reports Server (NTRS)

Mizuno, T.; Miyawaki, R.; Ebisawa, K.; Kubota, A.; Miyamoto, M.; Winter, L.; Ueda, Y.; Isobe, N.; Dewangan, G.; Mushotzky, R.F.;

Flexible, highly efficient all-polymer solar cells

PubMed Central

Kim, Taesu; Kim, Jae-Han; Kang, Tae Eui; Lee, Changyeon; Kang, Hyunbum; Shin, Minkwan; Wang, Cheng; Ma, Biwu; Jeong, Unyong; Kim, Taek-Soo; Kim, Bumjoon J.

2015-01-01

All-polymer solar cells have shown great potential as flexible and portable power generators. These devices should offer good mechanical endurance with high power-conversion efficiency for viability in commercial applications. In this work, we develop highly efficient and mechanically robust all-polymer solar cells that are based on the PBDTTTPD polymer donor and the P(NDI2HD-T) polymer acceptor. These systems exhibit high power-conversion efficiency of 6.64%. Also, the proposed all-polymer solar cells have even better performance than the control polymer-fullerene devices with phenyl-C61-butyric acid methyl ester (PCBM) as the electron acceptor (6.12%). More importantly, our all-polymer solar cells exhibit dramatically enhanced strength and flexibility compared with polymer/PCBM devices, with 60- and 470-fold improvements in elongation at break and toughness, respectively. The superior mechanical properties of all-polymer solar cells afford greater tolerance to severe deformations than conventional polymer-fullerene solar cells, making them much better candidates for applications in flexible and portable devices. PMID:26449658

Compassionate love buffers stress-reactive mothers from fight-or-flight parenting.

PubMed

Miller, Jonas G; Kahle, Sarah; Lopez, Monica; Hastings, Paul D

2015-01-01

The links among mothers' compassionate love for their child, autonomic nervous system activity, and parenting behavior during less and more challenging mother-child interactions were examined. Mothers expressed and reported less negative affect when they exhibited autonomic patterns of increased parasympathetic dominance (high parasympathetic and low sympathetic activation) or autonomic coactivation (high parasympathetic and high sympathetic activation) during the less challenging interaction and autonomic coactivation during the more challenging interaction. Compassionate love predicted less reported and observed negativity in mothers who showed increased sympathetic nervous system dominance (high sympathetic and low parasympathetic activation). Compassionate love appeared to help mothers, and particularly those who experienced strong physiological arousal during difficult parenting situations, establish positive socialization contexts for their children and avoid stress-induced adverse parenting.

Energy Efficiency and Environmental Impact Analyses of Supermarket Refrigeration Systems

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

Fricke, Brian A; Bansal, Pradeep; Zha, Shitong

This paper presents energy and life cycle climate performance (LCCP) analyses of a variety of supermarket refrigeration systems to identify designs that exhibit low environmental impact and high energy efficiency. EnergyPlus was used to model refrigeration systems in a variety of climate zones across the United States. The refrigeration systems that were modeled include the traditional multiplex DX system, cascade systems with secondary loops and the transcritical CO2 system. Furthermore, a variety of refrigerants were investigated, including R-32, R-134a, R-404A, R-1234yf, R-717, and R-744. LCCP analysis was used to determine the direct and indirect carbon dioxide emissions resulting from themore » operation of the various refrigeration systems over their lifetimes. Our analysis revealed that high-efficiency supermarket refrigeration systems may result in up to 44% less energy consumption and 78% reduced carbon dioxide emissions compared to the baseline multiplex DX system. This is an encouraging result for legislators, policy makers and supermarket owners to select low emission, high-efficiency commercial refrigeration system designs for future retrofit and new projects.« less

Highly stable families of soliton molecules in fiber-optic systems

NASA Astrophysics Data System (ADS)

Moubissi, A.-B.; Tchofo Dinda, P.; Nse Biyoghe, S.

2018-04-01

We develop an efficient approach to the design of families of single solitons and soliton molecules most suited to a given fiber system. The obtained solitonic entities exhibit very high stability, with a robustness which allows them to propagate over thousands of kilometers and to survive collisions with other solitonic entities. Our approach enables the generation of a large number of solitonic entities, including families of single solitons and two-soliton molecules, which can be distinguished sufficiently by their respective profiles or energy levels, and so can be easily identifiable and detectable without ambiguity. We discuss the possible use of such solitonic entities as symbols of a multi-level modulation format in fiber-optic communication systems.

A Fiber-Optic System Generating Pulses of High Spectral Density

NASA Astrophysics Data System (ADS)

Abramov, A. S.; Zolotovskii, I. O.; Korobko, D. A.; Fotiadi, A. A.

2018-03-01

A cascade fiber-optic system that generates pulses of high spectral density by using the effect of nonlinear spectral compression is proposed. It is demonstrated that the shape of the pulse envelope substantially influences the degree of compression of its spectrum. In so doing, maximum compression is achieved for parabolic pulses. The cascade system includes an optical fiber exhibiting normal dispersion that decreases along the fiber length, thereby ensuring that the pulse envelope evolves toward a parabolic shape, along with diffraction gratings and a fiber spectral compressor. Based on computer simulation, we determined parameters of cascade elements leading to maximum spectral density of radiation originating from a subpicosecond laser pulse of medium energy.

Facilitated charge transport in ternary interconnected electrodes for flexible supercapacitors with excellent power characteristics

NASA Astrophysics Data System (ADS)

Chen, Wanjun; He, Yongmin; Li, Xiaodong; Zhou, Jinyuan; Zhang, Zhenxing; Zhao, Changhui; Gong, Chengshi; Li, Shuankui; Pan, Xiaojun; Xie, Erqing

2013-11-01

Flexible and high performance supercapacitors are very critical in modern society. In order to develop the flexible supercapacitors with high power density, free-standing and flexible three-dimensional graphene/carbon nanotubes/MnO2 (3DG/CNTs/MnO2) composite electrodes with interconnected ternary 3D structures were fabricated, and the fast electron and ion transport channels were effectively constructed in the rationally designed electrodes. Consequently, the obtained 3DG/CNTs/MnO2 composite electrodes exhibit superior specific capacitance and rate capability compared to 3DG/MnO2 electrodes. Furthermore, the 3DG/CNTs/MnO2 based asymmetric supercapacitor demonstrates the maximum energy and power densities of 33.71 W h kg-1 and up to 22 727.3 W kg-1, respectively. Moreover, the asymmetric supercapacitor exhibits excellent cycling stability with 95.3% of the specific capacitance maintained after 1000 cycle tests. Our proposed synthesis strategy to construct the novel ternary 3D structured electrodes can be efficiently applied to other high performance energy storage/conversion systems.Flexible and high performance supercapacitors are very critical in modern society. In order to develop the flexible supercapacitors with high power density, free-standing and flexible three-dimensional graphene/carbon nanotubes/MnO2 (3DG/CNTs/MnO2) composite electrodes with interconnected ternary 3D structures were fabricated, and the fast electron and ion transport channels were effectively constructed in the rationally designed electrodes. Consequently, the obtained 3DG/CNTs/MnO2 composite electrodes exhibit superior specific capacitance and rate capability compared to 3DG/MnO2 electrodes. Furthermore, the 3DG/CNTs/MnO2 based asymmetric supercapacitor demonstrates the maximum energy and power densities of 33.71 W h kg-1 and up to 22 727.3 W kg-1, respectively. Moreover, the asymmetric supercapacitor exhibits excellent cycling stability with 95.3% of the specific capacitance maintained after 1000 cycle tests. Our proposed synthesis strategy to construct the novel ternary 3D structured electrodes can be efficiently applied to other high performance energy storage/conversion systems. Electronic supplementary information (ESI) available: Additional experimental details; calculations of the specific capacitances, and energy and power densities; additional SEM and optical images; XPS results; additional electrochemical results. See DOI: 10.1039/c3nr03923d

An Evaluation of the Elbit Canary and DynaSense PocketNIRS In-Flight Physiological Monitoring Systems

DTIC Science & Technology

2017-01-04

you have normal pulmonary function? YES NO 6. Have you ever been diagnosed with heart /circulatory disease ? YES NO 7. Do you...total dropout, the Canary system occasionally exhibited long stretches of data with sporadic heart rate signal dropout accompanied by high variance...values as low as 86%. This occurs over a timespan with sporadic heart rate signal dropout and greater mismatch between Canary and Ohmeda HR

Large area silicon sheet by EFG

NASA Technical Reports Server (NTRS)

Morrison, A. D.; Ravi, K. V.; Rao, C. V. H.; Surek, T.; Bliss, D. F.; Garone, L. C.; Hogencamp, R. W.

1976-01-01

Progress in a program to produce high speed, thin, wide silicon sheets for fabricating 10% efficient solar cells is reported. An EFG ribbon growth system was used to perform growth rate and ribbon thickness experiments. A new, wide ribbon growth system was developed. A theoretical study of stresses in ribbons was also conducted. The EFG ribbons were observed to exhibit a characteristic defect structure which is orientation dependent in the early stages of growth.

High Gloss Corrosion-Resistant Coatings

DTIC Science & Technology

1991-08-27

removal and parts by weight of a zinc salt of a substituted benioic certainly saves on manpower that would generally be acid , and 4 to 27 pans by...system consisting essentially of zinc molybdate, zinc salt of benzoic acids , and zinc phosphate in specific ratio’s. The coating exhibits good...polymeric binder and 18 to 70 percent by weight of a pigment system consisting essen- tially of zinc molybdate. zinc salt of benzoic acids , and zinc

Multi-step cure kinetic model of ultra-thin glass fiber epoxy prepreg exhibiting both autocatalytic and diffusion-controlled regimes under isothermal and dynamic-heating conditions

NASA Astrophysics Data System (ADS)

Kim, Ye Chan; Min, Hyunsung; Hong, Sungyong; Wang, Mei; Sun, Hanna; Park, In-Kyung; Choi, Hyouk Ryeol; Koo, Ja Choon; Moon, Hyungpil; Kim, Kwang J.; Suhr, Jonghwan; Nam, Jae-Do

2017-08-01

As packaging technologies are demanded that reduce the assembly area of substrate, thin composite laminate substrates require the utmost high performance in such material properties as the coefficient of thermal expansion (CTE), and stiffness. Accordingly, thermosetting resin systems, which consist of multiple fillers, monomers and/or catalysts in thermoset-based glass fiber prepregs, are extremely complicated and closely associated with rheological properties, which depend on the temperature cycles for cure. For the process control of these complex systems, it is usually required to obtain a reliable kinetic model that could be used for the complex thermal cycles, which usually includes both the isothermal and dynamic-heating segments. In this study, an ultra-thin prepreg with highly loaded silica beads and glass fibers in the epoxy/amine resin system was investigated as a model system by isothermal/dynamic heating experiments. The maximum degree of cure was obtained as a function of temperature. The curing kinetics of the model prepreg system exhibited a multi-step reaction and a limited conversion as a function of isothermal curing temperatures, which are often observed in epoxy cure system because of the rate-determining diffusion of polymer chain growth. The modified kinetic equation accurately described the isothermal behavior and the beginning of the dynamic-heating behavior by integrating the obtained maximum degree of cure into the kinetic model development.

Implicit Memory in Monkeys: Development of a Delay Eyeblink Conditioning System with Parallel Electromyographic and High-Speed Video Measurements.

PubMed

Kishimoto, Yasushi; Yamamoto, Shigeyuki; Suzuki, Kazutaka; Toyoda, Haruyoshi; Kano, Masanobu; Tsukada, Hideo; Kirino, Yutaka

2015-01-01

Delay eyeblink conditioning, a cerebellum-dependent learning paradigm, has been applied to various mammalian species but not yet to monkeys. We therefore developed an accurate measuring system that we believe is the first system suitable for delay eyeblink conditioning in a monkey species (Macaca mulatta). Monkey eyeblinking was simultaneously monitored by orbicularis oculi electromyographic (OO-EMG) measurements and a high-speed camera-based tracking system built around a 1-kHz CMOS image sensor. A 1-kHz tone was the conditioned stimulus (CS), while an air puff (0.02 MPa) was the unconditioned stimulus. EMG analysis showed that the monkeys exhibited a conditioned response (CR) incidence of more than 60% of trials during the 5-day acquisition phase and an extinguished CR during the 2-day extinction phase. The camera system yielded similar results. Hence, we conclude that both methods are effective in evaluating monkey eyeblink conditioning. This system incorporating two different measuring principles enabled us to elucidate the relationship between the actual presence of eyelid closure and OO-EMG activity. An interesting finding permitted by the new system was that the monkeys frequently exhibited obvious CRs even when they produced visible facial signs of drowsiness or microsleep. Indeed, the probability of observing a CR in a given trial was not influenced by whether the monkeys closed their eyelids just before CS onset, suggesting that this memory could be expressed independently of wakefulness. This work presents a novel system for cognitive assessment in monkeys that will be useful for elucidating the neural mechanisms of implicit learning in nonhuman primates.

Chemiresistive Graphene Sensors for Ammonia Detection.

PubMed

Mackin, Charles; Schroeder, Vera; Zurutuza, Amaia; Su, Cong; Kong, Jing; Swager, Timothy M; Palacios, Tomás

2018-05-09

The primary objective of this work is to demonstrate a novel sensor system as a convenient vehicle for scaled-up repeatability and the kinetic analysis of a pixelated testbed. This work presents a sensor system capable of measuring hundreds of functionalized graphene sensors in a rapid and convenient fashion. The sensor system makes use of a novel array architecture requiring only one sensor per pixel and no selector transistor. The sensor system is employed specifically for the evaluation of Co(tpfpp)ClO 4 functionalization of graphene sensors for the detection of ammonia as an extension of previous work. Co(tpfpp)ClO 4 treated graphene sensors were found to provide 4-fold increased ammonia sensitivity over pristine graphene sensors. Sensors were also found to exhibit excellent selectivity over interfering compounds such as water and common organic solvents. The ability to monitor a large sensor array with 160 pixels provides insights into performance variations and reproducibility-critical factors in the development of practical sensor systems. All sensors exhibit the same linearly related responses with variations in response exhibiting Gaussian distributions, a key finding for variation modeling and quality engineering purposes. The mean correlation coefficient between sensor responses was found to be 0.999 indicating highly consistent sensor responses and excellent reproducibility of Co(tpfpp)ClO 4 functionalization. A detailed kinetic model is developed to describe sensor response profiles. The model consists of two adsorption mechanisms-one reversible and one irreversible-and is shown capable of fitting experimental data with a mean percent error of 0.01%.

Comparative mapping of serotonin-immunoreactive neurons in the central nervous systems of nudibranch molluscs.

PubMed

Newcomb, James M; Fickbohm, David J; Katz, Paul S

2006-11-20

The serotonergic systems in nudibranch molluscs were compared by mapping the locations of serotonin-immunoreactive (5-HT-ir) neurons in 11 species representing all four suborders of the nudibranch clade: Dendronotoidea (Tritonia diomedea, Tochuina tetraquetra, Dendronotus iris, Dendronotus frondosus, and Melibe leonina), Aeolidoidea (Hermissenda crassicornis and Flabellina trophina), Arminoidea (Dirona albolineata, Janolus fuscus, and Armina californica), and Doridoidea (Triopha catalinae). A nomenclature is proposed to standardize reports of cell location in species with differing brain morphologies. Certain patterns of 5-HT immunoreactivity were found to be consistent for all species, such as the presence of 5-HT-ir neurons in the pedal and cerebral ganglia. Also, particular clusters of 5-HT-ir neurons in the anterior and posterior regions of the dorsal surface of the cerebral ganglion were always present. However, there were interspecies differences in the number of 5-HT-ir neurons in each cluster, and some clusters even exhibited strong intraspecies variability that was only weakly correlated with brain size. Phylogenetic analysis suggests that the presence of particular classes of 5-HT-ir neurons exhibits a great deal of homoplasy. The conserved features of the nudibranch serotonergic system presumably represent the shared ancestral structure, whereas the derived characters suggest substantial independent evolutionary changes in the number and presence of serotonergic neurons. Although a number of studies have demonstrated phylogenetic variability of peptidergic systems, this study suggests that serotonergic systems may also exhibit a high degree of homoplasy in some groups of organisms.

Maternal "junk-food" feeding of rat dams alters food choices and development of the mesolimbic reward pathway in the offspring.

PubMed

Ong, Z Y; Muhlhausler, B S

2011-07-01

Individuals exposed to high-fat, high-sugar diets before birth have an increased risk of obesity in later life. Recent studies have shown that these offspring exhibit increased preference for fat, leading to suggestions that perinatal exposure to high-fat, high-sugar foods results in permanent changes within the central reward system that increase the subsequent drive to overconsume palatable foods. The present study has determined the effect of a maternal "junk-food" diet on the expression of key components of the mesolimbic reward pathway in the offspring of rat dams at 6 wk and 3 mo of age. We show that offspring of junk-food-fed (JF) dams exhibit higher fat intake from weaning until at least 3 mo of age (males: 16 ± 0.6 vs. 11 ± 0.8 g/kg/d; females: 19 ± 1.3 vs. 13 ± 0.4 g/kg/d; P<0.01). mRNA expression of μ-opioid receptor (Mu) was 1.6-fold higher (P<0.01) and dopamine active transporter (DAT) was 2-fold lower (P<0.05) in JF offspring at 6 wk of age. By 3 mo, these differences were reversed, and Mu mRNA expression was 2.8-fold lower (P<0.01) and DAT mRNA expression was 1.9-fold higher (P<0.01) in the JF offspring. These findings suggest that perinatal exposure to high-fat, high-sugar diets results in altered development of the central reward system, resulting in increased fat intake and altered response of the reward system to excessive junk-food intake in postnatal life.

Construction of high-dimensional universal quantum logic gates using a Λ system coupled with a whispering-gallery-mode microresonator.

PubMed

He, Ling Yan; Wang, Tie-Jun; Wang, Chuan

2016-07-11

High-dimensional quantum system provides a higher capacity of quantum channel, which exhibits potential applications in quantum information processing. However, high-dimensional universal quantum logic gates is difficult to achieve directly with only high-dimensional interaction between two quantum systems and requires a large number of two-dimensional gates to build even a small high-dimensional quantum circuits. In this paper, we propose a scheme to implement a general controlled-flip (CF) gate where the high-dimensional single photon serve as the target qudit and stationary qubits work as the control logic qudit, by employing a three-level Λ-type system coupled with a whispering-gallery-mode microresonator. In our scheme, the required number of interaction times between the photon and solid state system reduce greatly compared with the traditional method which decomposes the high-dimensional Hilbert space into 2-dimensional quantum space, and it is on a shorter temporal scale for the experimental realization. Moreover, we discuss the performance and feasibility of our hybrid CF gate, concluding that it can be easily extended to a 2n-dimensional case and it is feasible with current technology.

Aquaporins in desert rodent physiology.

PubMed

Pannabecker, Thomas L

2015-08-01

Desert rodents face a sizeable challenge in maintaining salt and water homeostasis due to their life in an arid environment. A number of their organ systems exhibit functional characteristics that limit water loss above that which occurs in non-desert species under similar conditions. These systems include renal, pulmonary, gastrointestinal, nasal, and skin epithelia. The desert rodent kidney preserves body water by producing a highly concentrated urine that reaches a maximum osmolality nearly three times that of the common laboratory rat. The precise mechanism by which urine is concentrated in any mammal is unknown. Insights into the process may be more apparent in species that produce highly concentrated urine. Aquaporin water channels play a fundamental role in water transport in several desert rodent organ systems. The role of aquaporins in facilitating highly effective water preservation in desert rodents is only beginning to be explored. The organ systems of desert rodents and their associated AQPs are described. © 2015 Marine Biological Laboratory.

Vertically homogeneous stationary tornado-type vortex

NASA Astrophysics Data System (ADS)

Rutkevich, P. B.; Rutkevych, P. P.

2010-05-01

Tornado is regarded as one of the most dangerous atmosphere phenomena. The tornado phenomenon has been intensively studied so far, however, there is still no established and accepted theory of how tornadoes form, an uncertainty still exists concerning extreme winds and pressure drops in tornadoes. It is commonly accepted that it is possible to describe tornado from the set of nonlinear hydrodynamical equations, however, it is still unclear which non-linear processes are responsible for its formation. Nonlinear terms in the system are associated with either centrifugal force, or entropy transport, or transport of humidity. It appears that the amount and spatial distribution of precipitation with the convection are important indicators of the weather phenomena associated with a particular storm. The low-precipitation supercells that produce relatively little precipitation and yet show clear visual signs of rotation. Low-precipitation supercells occur most often near the surface dryline and, owing to the sparse precipitation and relatively dry environments with little cloudiness. Low-precipitation storms are frequently non-tornadic and many are non-severe despite exhibiting persistent rotation. On the other hand, the so-called high-precipitation storms are characterized by substantial precipitation within their mesocyclonic circulations. When high-precipitation storms have a recognizable hook radar echo, reflectivity in the hook is comparable to those in the precipitation core. High-precipitation supercells are probably the most common form of supercell and produce severe weather of all types including tornadoes. Therefore, in this work we consider a hydrodynamic system with only one nonlinear term associated with atmosphere humidity, which yields energy to the system. The tornado vortex is usually to a good approximation cylindrical so we use cylindrical geometry and homogeneity in vertical direction. In this case the problem reduces to a system of ordinary differential equations. Rotation in the vortex is associated with compressibility so we also take into account the compressibility of the gas. Under certain approximations the problem reduces to a single high-order nonlinear equation. Numerical solution of the obtained high-order equation describes all three velocity components and all thermodynamic parameters in the system. The system exhibits high rotation and strong vertical air flow in the middle part of the vortex.

Characteristics and oil sorption effectiveness of kapok fibre, sugarcane bagasse and rice husks: oil removal suitability matrix.

PubMed

Ali, Norizan; El-Harbawi, Mohanad; Jabal, Ayman Abo; Yin, Chun-Yang

2012-01-01

The characteristics and water/oil sorption effectiveness ofkapok fibre, sugarcane bagasse and rice husks have been compared. The three biomass types were subjected to field emission scanning electron microscopy-energy dispersive X-ray spectroscopy and surface tension analyses for liquid-air and oil-water systems were conducted. Both kapok fibre and sugarcane bagasse exhibit excellent oil sorption capabilities for diesel, crude, new engine and used engine oils as their oil sorption capacities all exceed 10 g/g. The synthetic sorbent exhibits oil sorption capacities comparable with sugarcane bagasse, while rice husks exhibit the lowest oil sorption capacities among all the sorbents. Kapok fibre shows overwhelmingly high oil-to-water sorption (O/W) ratios ranging from 19.35 to 201.53 while sugarcane bagasse, rice husks and synthetic sorbent have significantly lower O/W ratios (0.76-2.69). This suggests that kapok fibre is a highly effective oil sorbent even in well-mixed oil-water media. An oil sorbent suitability matrix is proposed to aid stakeholders in evaluating customized oil removal usage of the natural sorbents.

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

None available

For the purpose of this STI product and unless otherwise stated, hybrid fuel cell systems are power generation systems in which a high temperature fuel cell is combined with another power generating technology. The resulting system exhibits a synergism in which the combination performs with an efficiency far greater than can be provided by either system alone. Hybrid fuel cell designs under development include fuel cell with gas turbine, fuel cell with reciprocating (piston) engine, and designs that combine different fuel cell technologies. Hybrid systems have been extensively analyzed and studied over the past five years by the Department ofmore » Energy (DOE), industry, and others. These efforts have revealed that this combination is capable of providing remarkably high efficiencies. This attribute, combined with an inherent low level of pollutant emission, suggests that hybrid systems are likely to serve as the next generation of advanced power generation systems.« less

High Solids Coating System

DTIC Science & Technology

1980-06-01

environmental pollution and increased worker safety. One formulation, consisting of a combination of Acryloid AU-568 (oxazolidine), NIAX PCP-0300 (polyol), and Desmodur N-100 (polyisocyanate) was developed under the initial contract and found to exhibit performance properties closely approximating the program goals. During the present contract, this formulation was further evaluated. Attempts to upgrade the properties not meeting the performance specifications were made. Also, new commercially available resins were evaluated for incorporation into the high solids

A One-Component, Fast-Cure, and Economical Epoxy Resin System Suitable for Liquid Molding of Automotive Composite Parts.

PubMed

Wang, Yiru; Liu, Wanshuang; Qiu, Yiping; Wei, Yi

2018-04-27

Imidazole cured epoxy resin systems were evaluated for one-component, fast-curing resins for liquid molding of automotive composite parts according to industry requirements. It was demonstrated that an epoxy resin-1-(cyanoethyl)-2-ethyl-4-methylimidazol(EP-1C2E4MIM) system would cure in a few minutes at 120 °C, while exhibiting acceptable pot life, viscosity profiles, and low water absorption. Moreover, this system yielded high T g parts with mechanical properties similar to the amine-epoxy systems, which are the mainstream two-component epoxy resin systems for automobiles.

A One-Component, Fast-Cure, and Economical Epoxy Resin System Suitable for Liquid Molding of Automotive Composite Parts

PubMed Central

Wang, Yiru; Qiu, Yiping; Wei, Yi

2018-01-01

Imidazole cured epoxy resin systems were evaluated for one-component, fast-curing resins for liquid molding of automotive composite parts according to industry requirements. It was demonstrated that an epoxy resin-1-(cyanoethyl)-2-ethyl-4-methylimidazol(EP-1C2E4MIM) system would cure in a few minutes at 120 °C, while exhibiting acceptable pot life, viscosity profiles, and low water absorption. Moreover, this system yielded high Tg parts with mechanical properties similar to the amine-epoxy systems, which are the mainstream two-component epoxy resin systems for automobiles. PMID:29702575

Flexible Strain Sensors Fabricated by Meniscus-Guided Printing of Carbon Nanotube-Polymer Composites.

PubMed

Wajahat, Muhammad; Lee, Sanghyeon; Kim, Jung Hyun; Chang, Won Suk; Pyo, Jaeyeon; Cho, Sung Ho; Seol, Seung Kwon

2018-06-13

Printed strain sensors have promising potential as a human-machine interface (HMI) for health-monitoring systems, human-friendly wearable interactive systems, and smart robotics. Herein, flexible strain sensors based on carbon nanotube (CNT)-polymer composites were fabricated by meniscus-guided printing using a CNT ink formulated from multiwall nanotubes (MWNTs) and polyvinylpyrrolidone (PVP); the ink was suitable for micropatterning on nonflat (or curved) substrates and even three-dimensional structures. The printed strain sensors exhibit a reproducible response to applied tensile and compressive strains, having gauge factors of 13.07 under tensile strain and 12.87 under compressive strain; they also exhibit high stability during ∼1500 bending cycles. Applied strains induce a contact rearrangement of the MWNTs and a change in the tunneling distance between them, resulting in a change in the resistance (Δ R/ R 0 ) of the sensor. Printed MWNT-PVP sensors were used in gloves for finger movement detection; these can be applied to human motion detection and remote control of robotic equipment. Our results demonstrate that meniscus-guided printing using CNT inks can produce highly flexible, sensitive, and inexpensive HMI devices.

Controlled insertional mutagenesis using a LINE-1 (ORFeus) gene-trap mouse model.

PubMed

O'Donnell, Kathryn A; An, Wenfeng; Schrum, Christina T; Wheelan, Sarah J; Boeke, Jef D

2013-07-16

A codon-optimized mouse LINE-1 element, ORFeus, exhibits dramatically higher retrotransposition frequencies compared with its native long interspersed element 1 counterpart. To establish a retrotransposon-mediated mouse model with regulatable and potent mutagenic capabilities, we generated a tetracycline (tet)-regulated ORFeus element harboring a gene-trap cassette. Here, we show that mice expressing tet-ORFeus broadly exhibit robust retrotransposition in somatic tissues when treated with doxycycline. Consistent with a significant mutagenic burden, we observed a reduced number of double transgenic animals when treated with high-level doxycycline during embryogenesis. Transgene induction in skin resulted in a white spotting phenotype due to somatic ORFeus-mediated mutations that likely disrupt melanocyte development. The data suggest a high level of transposition in melanocyte precursors and consequent mutation of genes important for melanoblast proliferation, differentiation, or migration. These findings reveal the utility of a retrotransposon-based mutagenesis system as an alternative to existing DNA transposon systems. Moreover, breeding these mice to different tet-transactivator/reversible tet-transactivator lines supports broad functionality of tet-ORFeus because of the potential for dose-dependent, tissue-specific, and temporal-specific mutagenesis.

Feasibility of high recovery highwall mining equipment. Final report

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

Not Available

1981-01-01

Three equipment systems exhibited significant promise: the RSV Miner, a surface longwall using standard underground equipment, and the variable angle auger. Other equipment systems showing considerable merit were the surface shortwall, and the two extended depth augers. Of the three most significant systems, the RSV Miner exhibits the greatest versatility and adaptability. It may be used competently in many surface mining applications and readily adapts to geologic anomalies and changing seam heights. The machine employs steering and guidance equipment and provides the necessary capabilities for extended depth operation. Safety is good, as no men are required to work underground. However,more » most important is the system's recovery factor of approximately 75% to 80% of the in-situ coal reserve within reach. The surface longwall system using standard underground equipment (preferably a ranging drum shearer in conjunction with shield supports) is most suited to either a trench mining or a modified area mining application. Both applications would allow the length of the face to be held constant. Another important consideration is legal requirements for a tailgate entry, which would necessitate additional equipment for development in a modified area mining application. When compared to surface shortwall, surface longwall exhibits higher productivity, a far greater equipment selection which allows system tailoring to geologic conditions, and greater roof control due to the significantly smaller section of overburden that must be supported. Recovery should approach, and possibly exceed, 90% of the coal in-place. The variable angle auger, which is currently only a concept, fills a very real need for which no other equipment is available at this time.« less

In-situ and real-time growth observation of high-quality protein crystals under quasi-microgravity on earth.

PubMed

Nakamura, Akira; Ohtsuka, Jun; Kashiwagi, Tatsuki; Numoto, Nobutaka; Hirota, Noriyuki; Ode, Takahiro; Okada, Hidehiko; Nagata, Koji; Kiyohara, Motosuke; Suzuki, Ei-Ichiro; Kita, Akiko; Wada, Hitoshi; Tanokura, Masaru

2016-02-26

Precise protein structure determination provides significant information on life science research, although high-quality crystals are not easily obtained. We developed a system for producing high-quality protein crystals with high throughput. Using this system, gravity-controlled crystallization are made possible by a magnetic microgravity environment. In addition, in-situ and real-time observation and time-lapse imaging of crystal growth are feasible for over 200 solution samples independently. In this paper, we also report results of crystallization experiments for two protein samples. Crystals grown in the system exhibited magnetic orientation and showed higher and more homogeneous quality compared with the control crystals. The structural analysis reveals that making use of the magnetic microgravity during the crystallization process helps us to build a well-refined protein structure model, which has no significant structural differences with a control structure. Therefore, the system contributes to improvement in efficiency of structural analysis for "difficult" proteins, such as membrane proteins and supermolecular complexes.

High Performance MG-System Alloys For Weight Saving Applications: First Year Results From The Green Metallurgy EU Project

NASA Astrophysics Data System (ADS)

D'Errico, Fabrizio; Plaza, Gerardo Garces; Hofer, Markus; Kim, Shae K.

The GREEN METALLURGY Project, a LIFE+ project co-financed by the EU Commission, has just concluded its first year. The Project seeks to set manufacturing processes at a pre-industrial scale for nanostructured-based high-performance Mg-Zn(Y) magnesium alloys. The Project's goal is the reduction of specific energy consumed and the overall carbon-footprint produced in the cradle-to-exit gate phases. Preliminary results addressed potentialities of the upstream manufacturing process pathway. Two Mg-Zn(Y) system alloys with rapid solidifying powders have been produced and directly extruded for 100% densification. Examination of the mechanical properties showed that such materials exhibit strength and elongation comparable to several high performing aluminum alloys; 390 MPa and 440 MPa for the average UTS for two different system alloys, and 10% and 15% elongations for two system alloys. These results, together with the low-environmental impact targeted, make these novel Mg alloys competitive as lightweight high-performance materials for automotive components.

Adaptive Control for Microgravity Vibration Isolation System

NASA Technical Reports Server (NTRS)

Yang, Bong-Jun; Calise, Anthony J.; Craig, James I.; Whorton, Mark S.

2005-01-01

Most active vibration isolation systems that try to a provide quiescent acceleration environment for space science experiments have utilized linear design methods. In this paper, we address adaptive control augmentation of an existing classical controller that employs a high-gain acceleration feedback together with a low-gain position feedback to center the isolated platform. The control design feature includes parametric and dynamic uncertainties because the hardware of the isolation system is built as a payload-level isolator, and the acceleration Sensor exhibits a significant bias. A neural network is incorporated to adaptively compensate for the system uncertainties, and a high-pass filter is introduced to mitigate the effect of the measurement bias. Simulations show that the adaptive control improves the performance of the existing acceleration controller and keep the level of the isolated platform deviation to that of the existing control system.

Minimum fuel control of a vehicle with a continuously variable transmission. [control system simulation

NASA Technical Reports Server (NTRS)

Burghart, J. H.; Donoghue, J. F.

1980-01-01

The design and evaluation of a control system for a sedan with a heat engine and a continuously variable transmission, is considered in a effort to minimize fuel consumption and achieve satisfactory dynamic response of vehicle variables as the vehicle is driven over a standard driving cycle. Even though the vehicle system was highly nonlinear, attention was restricted to linear control algorithms which could be easily understood and implemented demonstrated by simulation. Simulation results also revealed that the vehicle could exhibit unexpected dynamic behavior which must be taken into account in any control system design.

Contact binary stars

NASA Technical Reports Server (NTRS)

Dupree, A. K.

1983-01-01

Ultraviolet and X-ray surveys of the W Ursae Majoris type stars are reviewed. These systems exhibit extended coronas and transition regions that are confined close to the optically determined surfaces. Correlations of X-ray activity with period or rotational velocity indicate a turn-over or saturation of emission at the short periods or high velocities found in the W UMa-type systems. For a number of systems, ultraviolet emission appears to be anti-correlated with the strength of X-ray emission. These observations are discussed in terms of solar structures, activity, and evolution.

Synthesis of Multifunctional Nanoparticles for Cancer Diagnostics and Therapeutics

NASA Astrophysics Data System (ADS)

Fang, Chen

2011-12-01

Magnetic nanoparticles (MNPs) have attracted enormous research attention due to their unique magnetic properties that enable the detection by the non-invasive medical imaging modality---magnetic resonance imaging (MRI). By incorporating advanced features, such as specific targeting, multimodality, therapeutic delivery, the detectability and applicability of MNPs have been dramatically expanded. Smart and rational design on structure, composition and surface chemistry is essential to achieving desired properties in MNP systems, such as high sensitivity and colloidal stability, target specificity and/or multimodality. The goal of this research is to develop MNP-based platforms for the detection, diagnosis and treatment of cancer. MNPs with high contrast enhancement were coated with poly(ethylene glycol) (PEG)-based polymers to render aqueous stability and confer therapeutic-loading capability. Tumor-specific MNPs were developed by functionalization of nanoparticles with chlorotoxin (CTX) or arginine-glycine-aspartic acid (RGD) that targets, respectively, MMP-2 receptor or alphavbeta3 integrin overexpressed on a variety of cancer cells. The effects of ligands' molecular targets on the temporal and spatial distribution of MNPs within tumors were also investigated both in vitro and in vivo. All MNPs exhibited excellent long-term stability in cell culture media. CTX-labeled MNP exhibited sustained accumulation, penetration and distribution in the tumor mass. These findings revealed the influence of the targeting ligands on the intratumoral distribution of the ligand-enabled nanoprobes. To demonstrate the ability of nanoparticles as drug carrier, anthracyline chemotherapeutic drugs doxorubicin and mitoxantrone were attached to iron oxide nanoparticles. The theragnostic nanoparticles showed sufficient contrast enhancement and comparable anti-neoplastic efficacy in vitro. With flexible surface chemistry, our nanoparticle platform can be used in a modular fashion to conjugate biomolecules for intended applications, and the functionalized nanoparticle systems retain a prolonged stability and exhibit high tumor specificity. The study would establish the foundation for future development of integrated theragnostic systems for the treatment of cancer and other complex diseases.

Ni-DNA-based nanowires and nanodevices

NASA Astrophysics Data System (ADS)

Chang, Chia-Ching; Yuan, Chiun-Jye; Jian, Wen-Bin; Chen, Yu-Chang; di Ventra, Massimiliano

DNA is a highly versatile biopolymer that has been a recent focus in the field of nanomachines and nanoelectronics. DNA exhibits high stability, adjustable conductance, self-organizing capability, programmability and vast information storage. It is an ideal material in the applications of nanodevices, nanoelectronics, and molecular computing. Low conductance of native DNA renders applications difficult. However, doping with nickel ions tunes the DNA into a conducting polymer. Further studies showed that nickel ions containing DNA (Ni-DNA) nanowires exhibit characteristics of memristor and memcapacitor making them a potential mass information storage system. In summary, Ni-DNA has promising applications in a variety of fields, including nanoelectronics, biosensors and memcomputing. This study was supported in part by the Ministry of Science and Technology (MOST), Taiwan (ROC) MOST 103-2112-M-009-011 -MY3, and MOST 105-2627-M-009-006.

Disordered cellular automaton traffic flow model: phase separated state, density waves and self organized criticality

NASA Astrophysics Data System (ADS)

Fourrate, K.; Loulidi, M.

2006-01-01

We suggest a disordered traffic flow model that captures many features of traffic flow. It is an extension of the Nagel-Schreckenberg (NaSch) stochastic cellular automata for single line vehicular traffic model. It incorporates random acceleration and deceleration terms that may be greater than one unit. Our model leads under its intrinsic dynamics, for high values of braking probability pr, to a constant flow at intermediate densities without introducing any spatial inhomogeneities. For a system of fast drivers pr→0, the model exhibits a density wave behavior that was observed in car following models with optimal velocity. The gap of the disordered model we present exhibits, for high values of pr and random deceleration, at a critical density, a power law distribution which is a hall mark of a self organized criticality phenomena.

A Novel Characterization of Amalgamated Networks in Natural Systems

PubMed Central

Barranca, Victor J.; Zhou, Douglas; Cai, David

2015-01-01

Densely-connected networks are prominent among natural systems, exhibiting structural characteristics often optimized for biological function. To reveal such features in highly-connected networks, we introduce a new network characterization determined by a decomposition of network-connectivity into low-rank and sparse components. Based on these components, we discover a new class of networks we define as amalgamated networks, which exhibit large functional groups and dense connectivity. Analyzing recent experimental findings on cerebral cortex, food-web, and gene regulatory networks, we establish the unique importance of amalgamated networks in fostering biologically advantageous properties, including rapid communication among nodes, structural stability under attacks, and separation of network activity into distinct functional modules. We further observe that our network characterization is scalable with network size and connectivity, thereby identifying robust features significant to diverse physical systems, which are typically undetectable by conventional characterizations of connectivity. We expect that studying the amalgamation properties of biological networks may offer new insights into understanding their structure-function relationships. PMID:26035066

Porous Iron-Carboxylate Metal-Organic Framework: A Novel Bioplatform with Sustained Antibacterial Efficacy and Nontoxicity.

PubMed

Lin, Sha; Liu, Xiangmei; Tan, Lei; Cui, Zhenduo; Yang, Xianjin; Yeung, Kelvin W K; Pan, Haobo; Wu, Shuilin

2017-06-07

Sustained drug release plays a critical role in targeting the therapy of local diseases such as bacterial infections. In the present work, porous iron-carboxylate metal-organic framework [MOF-53(Fe)] nanoparticles (NPs) were designed to entrap the vancomycin (Van) drugs. This system exhibited excellent chemical stability under acidic conditions (pH 7.4, 6.5, and 5.5) and much higher drug-loading capability because of the high porosity and large surface area of MOF NPs. The results showed that the drug-loading ratio of Van could reach 20 wt % and that the antibacterial ratio of the MOF-53(Fe)/Van system against Staphylococcus aureus could reach up to 90%. In addition, this MOF-53(Fe)/Van system exhibited excellent biocompatibility because of its chemical stability and sustained release of iron ions. Hence, these porous MOF NPs are a promising bioplatform not only for local therapy of bacterial infections but also for other biomedical therapies for tissue regeneration.

Genetic evidence for polygynandry in the black-striped pipefish Syngnathus abaster: a microsatellite-based parentage analysis.

PubMed

Hübner, Kerstin; Gonzalez-Wanguemert, Mercedes; Diekmann, Onno E; Serrão, Ester A

2013-01-01

Sexual selection theory predicts that, in organisms with reversed sex roles, more polyandrous species exhibit higher levels of sexual dimorphism. In the family Syngnathidae (pipefish, seahorses, and seadragons), males provide all parental care by carrying developing embryos on their ventral surfaces, and females develop secondary sex characters. Syngnathids exhibit a variety of genetic mating patterns, making them an ideal group to test predictions of sexual selection theory. Here, we describe the mating system of the black-striped pipefish Syngnathus abaster, using 4 highly variable microsatellites to analyze parentage of 102 embryos. Results revealed that 1) both sexes mate multiple times over the course of a pregnancy (polygynandrous mating system), 2) eggs are spatially segregated by maternity within each brood pouch, and 3) larger females have higher mating success (Kolmogorov-Smirnov test; P < 0.05). Together with similar studies of other syngnathid species, our results support the hypothesis that the mating system is related to the intensity of sexual dimorphism.

In Vitro Analysis of the Role of Replication Protein A (RPA) and RPA Phosphorylation in ATR-mediated Checkpoint Signaling*

PubMed Central

Lindsey-Boltz, Laura A.; Reardon, Joyce T.; Wold, Marc S.; Sancar, Aziz

2012-01-01

Replication protein A (RPA) plays essential roles in DNA metabolism, including replication, checkpoint, and repair. Recently, we described an in vitro system in which the phosphorylation of human Chk1 kinase by ATR (ataxia telangiectasia mutated and Rad3-related) is dependent on RPA bound to single-stranded DNA. Here, we report that phosphorylation of other ATR targets, p53 and Rad17, has the same requirements and that RPA is also phosphorylated in this system. At high p53 or Rad17 concentrations, RPA phosphorylation is inhibited and, in this system, RPA with phosphomimetic mutations cannot support ATR kinase function, whereas a non-phosphorylatable RPA mutant exhibits full activity. Phosphorylation of these ATR substrates depends on the recruitment of ATR and the substrates by RPA to the RPA-ssDNA complex. Finally, mutant RPAs lacking checkpoint function exhibit essentially normal activity in nucleotide excision repair, revealing RPA separation of function for checkpoint and excision repair. PMID:22948311

In vitro analysis of the role of replication protein A (RPA) and RPA phosphorylation in ATR-mediated checkpoint signaling.

PubMed

Lindsey-Boltz, Laura A; Reardon, Joyce T; Wold, Marc S; Sancar, Aziz

2012-10-19

Replication protein A (RPA) plays essential roles in DNA metabolism, including replication, checkpoint, and repair. Recently, we described an in vitro system in which the phosphorylation of human Chk1 kinase by ATR (ataxia telangiectasia mutated and Rad3-related) is dependent on RPA bound to single-stranded DNA. Here, we report that phosphorylation of other ATR targets, p53 and Rad17, has the same requirements and that RPA is also phosphorylated in this system. At high p53 or Rad17 concentrations, RPA phosphorylation is inhibited and, in this system, RPA with phosphomimetic mutations cannot support ATR kinase function, whereas a non-phosphorylatable RPA mutant exhibits full activity. Phosphorylation of these ATR substrates depends on the recruitment of ATR and the substrates by RPA to the RPA-ssDNA complex. Finally, mutant RPAs lacking checkpoint function exhibit essentially normal activity in nucleotide excision repair, revealing RPA separation of function for checkpoint and excision repair.

Peak-dip-hump lineshape from holographic superconductivity

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

Chen, J.-W.; Kao, Y.-J.; Wen, W.-Y.

2010-07-15

We study the fermionic spectral function in a holographic superconductor model. At zero temperature, there is no horizon and hence the entropy of the system is zero after the backreaction of the condensate is taken into account. We find the system exhibits the famous peak-dip-hump lineshape with a sharp low-energy peak followed by a dip and then a hump at higher energies. This feature is widely observed in the spectrum of several high-T{sub c} superconductors.

Programmed packaging of multicomponent envelope-type nanoparticle system for gene delivery

NASA Astrophysics Data System (ADS)

Pozzi, Daniela; Marianecci, Carlotta; Carafa, Maria; Marchini, Cristina; Montani, Maura; Amici, Augusto; Caracciolo, Giulio

2010-05-01

A programmed packaging strategy to develop a multicomponent envelope-type nanoparticle system (MENS) is presented. To this end, we took specific advantage of using in-house tailored liposomes that have been recently shown to exhibit intrinsic endosomal rupture properties that allow plasmid DNA to escape from endosomes and to enter the nucleus with extremely high efficiency. Transfection efficiency experiments on NIH 3T3 mouse fibroblasts indicate that MENS is a promising transfection candidate.

A space necklace about the earth

NASA Technical Reports Server (NTRS)

Polyakov, G.

1977-01-01

A space elevator is forecasted for the first quarter of the 21st century, that will consist of a cable attached at the earth's equator, suspended in space by an artificial satellite in geosynchronous orbit. It is stated that such a transport system will supplement rockets as the railway supplements aircraft. Specific aspects of the system are examined, including provisions for artificial gravity, the development special composite construction materials exhibiting high strength and low mass, and spacecraft launching from the elevator.

A Carbon-Cotton Cathode with Ultrahigh-Loading Capability for Statically and Dynamically Stable Lithium–Sulfur Batteries

DOE PAGES

Chung, Sheng-Heng; Chang, Chi-Hao; Manthiram, Arumugam

2016-10-26

Sulfur exhibits a high theoretical capacity of 1675 mA h g -1 via a distinct conversion reaction, which is different from the insertion reactions in commercial lithium-ion batteries. In consideration of its conversion reaction battery chemistry, a custom design for electrode materials could establish the way for attaining high-loading capability while simultaneously maintaining high electrochemical utilization and stability. In this study, this process is undertaken by introducing carbon cotton as an attractive electrode-containment material for enhancing the dynamic and static stabilities of lithium-sulfur (Li-S) batteries. The carbon cotton possessing a hierarchical macro-/microporous architecture exhibits a high surface area of 805more » m 2 g -1 and high microporosity with a micropore area of 557 m 2 g -1. The macroporous channels allow the carbon cotton to load and stabilize a high amount of active material. The abundant microporous reaction sites spread throughout the carbon cotton facilitate the redox chemistry of the high-loading/content Li-S system. As a result, the high-loading carbon-cotton cathode exhibits (i) enhanced cycle stability with a good dynamic capacity retention of 70% after 100 cycles and (ii) improved cellstorage stability with a high static capacity retention of above 93% and a low time-dependent self-discharge rate of 0.12% per day after storing for a long period of 60 days. In conclusion, these carbon-cotton cathodes with the remarkably highest values reported so far of both sulfur loading (61.4 mg cm -2) and sulfur content (80 wt %) demonstrate enhanced electrochemical utilization with the highest areal, volumetric, and gravimetric capacities simultaneously.« less

A Carbon-Cotton Cathode with Ultrahigh-Loading Capability for Statically and Dynamically Stable Lithium–Sulfur Batteries

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

Chung, Sheng-Heng; Chang, Chi-Hao; Manthiram, Arumugam

Sulfur exhibits a high theoretical capacity of 1675 mA h g -1 via a distinct conversion reaction, which is different from the insertion reactions in commercial lithium-ion batteries. In consideration of its conversion reaction battery chemistry, a custom design for electrode materials could establish the way for attaining high-loading capability while simultaneously maintaining high electrochemical utilization and stability. In this study, this process is undertaken by introducing carbon cotton as an attractive electrode-containment material for enhancing the dynamic and static stabilities of lithium-sulfur (Li-S) batteries. The carbon cotton possessing a hierarchical macro-/microporous architecture exhibits a high surface area of 805more » m 2 g -1 and high microporosity with a micropore area of 557 m 2 g -1. The macroporous channels allow the carbon cotton to load and stabilize a high amount of active material. The abundant microporous reaction sites spread throughout the carbon cotton facilitate the redox chemistry of the high-loading/content Li-S system. As a result, the high-loading carbon-cotton cathode exhibits (i) enhanced cycle stability with a good dynamic capacity retention of 70% after 100 cycles and (ii) improved cellstorage stability with a high static capacity retention of above 93% and a low time-dependent self-discharge rate of 0.12% per day after storing for a long period of 60 days. In conclusion, these carbon-cotton cathodes with the remarkably highest values reported so far of both sulfur loading (61.4 mg cm -2) and sulfur content (80 wt %) demonstrate enhanced electrochemical utilization with the highest areal, volumetric, and gravimetric capacities simultaneously.« less

The regulation of rat activity following exposure to hyperdynamic fields

NASA Technical Reports Server (NTRS)

Fuller, Charles A.; Ishihama, Linda M.; Murakami, Dean M.

1993-01-01

The microgravity of space flight and the hyperdynamic fields produced via centrifugation have allowed researchers to examine the effect of altered gravitational environments on the regulation of physiological systems. In this study, a high frequency light/dark cycle was provided for 24 hours as an environmental challenge to assess the recovery of homeostatic and circadian components of physiological regulation in rats. For example, the nocturnal rat exhibited a homeostatic increase in body temperature during the dark periods and a decrease during the light periods. In addition, the magnitude of the body temperature response exhibits a time of day variation demonstrating the effect on circadian regulation.

New insights from a statistical analysis of IUE spectra of dwarf novae and nova-like stars. I - Inclination effects in lines and continua

NASA Technical Reports Server (NTRS)

La Dous, Constanze

1991-01-01

IUE observations of dwarf novae at maximum at quiescence and novalike objects at the high brightness state are analyzed for effects of the inclination angle on the emitted continuum and line radiation. A clear pattern in the continuum flux distribution is exhibited only by dwarf novae at maximum where some 80 percent of the non-double-eclipsing systems show essentially identical distributions. This result is not in disagreement with theoretical expectations. All classes of objects exhibit a clear, but in each case different, dependence of the line radiation on the inclination angle.

Oval gradient coils for an open magnetic resonance imaging system with a vertical magnetic field.

PubMed

Matsuzawa, Koki; Abe, Mitsushi; Kose, Katsumi; Terada, Yasuhiko

2017-05-01

Existing open magnetic resonance imaging (MRI) systems use biplanar gradient coils for the spatial encoding of signals. We propose using novel oval gradient coils for an open vertical-field MRI. We designed oval gradients for a 0.3T open MRI system and showed that such a system could outperform a traditional biplanar gradient system while maintaining adequate gradient homogeneity and subject accessibility. Such oval gradient coils would exhibit high efficiency, low inductance and resistance, and high switching capability. Although the designed oval Y and Z coils showed more heat dissipation and less cooling capability than biplanar coils with the same gap, they showed an efficient heat-dissipation path to the surrounding air, which would alleviate the heat problem. The performance of the designed oval-coil system was demonstrated experimentally by imaging a human hand. Copyright © 2017 Elsevier Inc. All rights reserved.

Compassionate Love Buffers Stress-Reactive Mothers From Fight-or-Flight Parenting

PubMed Central

Miller, Jonas G.; Kahle, Sarah; Lopez, Monica; Hastings, Paul D.

2015-01-01

The links among mothers’ compassionate love for their child, autonomic nervous system activity, and parenting behavior during less and more challenging mother–child interactions were examined. Mothers expressed and reported less negative affect when they exhibited autonomic patterns of increased parasympathetic dominance (high parasympathetic and low sympathetic activation) or autonomic coactivation (high parasympathetic and high sympathetic activation) during the less challenging interaction and autonomic coactivation during the more challenging interaction. Compassionate love predicted less reported and observed negativity in mothers who showed increased sympathetic nervous system dominance (high sympathetic and low parasympathetic activation). Compassionate love appeared to help mothers, and particularly those who experienced strong physiological arousal during difficult parenting situations, establish positive socialization contexts for their children and avoid stress-induced adverse parenting. PMID:25329554

Spectral imaging and passive sampling to investigate particle sources in urban desert regions.

PubMed

Wagner, Jeff; Casuccio, Gary

2014-07-01

Two types of electron microscopy analyses were employed along with geographic information system (GIS) mapping to investigate potential sources of PM2.5 and PM10 (airborne particulate matter smaller than 2.5 and 10 μm, respectively) in two urbanized desert areas known to exhibit PM excursions. Integrated spectral imaging maps were obtained from scanning electron microscopy/energy-dispersive X-ray spectroscopy (SEM/EDS) analyses of 13 filters collected in Imperial Valley, California. Seven were from 24 h PM10 Federal Reference Method (FRM) samplers and six were from PM2.5 FRM samplers. This technique enabled extraction of information from particles collected on complex filter matrices, and indicated that all samples exhibited substantial proportions of crustal particles. Six Imperial PM2.5 and PM10 filters selected from unusually high-PM days exhibited more large particles (2.5-15 and 10-30 μm, respectively) than did filters from low-PM days, and were more consistent with soils analyzed from the region. High winds were present on three of the six high-PM days. One of the high-PM2.5 filters also exhibited substantial fine carbonaceous soot PM, suggesting significant contributions from a combustion source. Computer-controlled SEM/EDS (CCSEM/EDS) was conducted on PM collected with UNC Passive samplers from Phoenix, Arizona. The passive samplers showed good agreement with co-located FRM PM10 and PM2.5 measurements (μg m(-3)), and also enabled detailed individual particle analysis. The CCSEM/EDS data revealed mostly crustal particles in both the Phoenix fine and coarse PM10 fractions. GIS maps of multiple dust-related parameters confirm that both Imperial Valley and Phoenix possess favorable conditions for airborne crustal PM from natural and anthropogenic sources.

Can one ``Hear'' the aggregation state of a granular system?

NASA Astrophysics Data System (ADS)

Kruelle, Christof A.; Sánchez, Almudena García

2013-06-01

If an ensemble of macroscopic particles is mechanically agitated the constant energy input is dissipated into the system by multiple inelastic collisions. As a result, the granular material can exhibit, depending on the magnitude of agitation, several physical states - like a gaseous phase for high energy input or a condensed state for low agitation. Here we introduce a new method for quantifying the acoustical response of the granular system. Our experimental system consists of a monodisperse packing of glass beads with a free upper surface, which is confined inside a cylindrical container. An electro-mechanical shaker exerts a sinusoidal vertical vibration at normalized accelerations well above the fluidization threshold for a monolayer of particles. By increasing the number of beads the granular gas suddenly collapses if a critical threshold is exceeded. The transition can be detected easily with a microphone connected to the soundcard of a PC. From the recorded audio track a FFT is calculated in real-time. Depending on either the number of particles at a fixed acceleration or the amount of energy input for a given number of particles, the resulting rattling noise exhibits a power spectrum with either the dominating (shaker) frequency plus higher harmonics for a granular crystal or a high-frequency broad-band noise for a granular gas, respectively. Our new method demonstrates that it is possible to quantify analytically the subjective audio impressions of a careful listener and thus to distinguish easily between different aggregation states of an excited granular system.

Synthesis of Porous Carbon Monoliths Using Hard Templates.

PubMed

Klepel, Olaf; Danneberg, Nina; Dräger, Matti; Erlitz, Marcel; Taubert, Michael

2016-03-21

The preparation of porous carbon monoliths with a defined shape via template-assisted routes is reported. Monoliths made from porous concrete and zeolite were each used as the template. The porous concrete-derived carbon monoliths exhibited high gravimetric specific surface areas up to 2000 m²·g -1 . The pore system comprised macro-, meso-, and micropores. These pores were hierarchically arranged. The pore system was created by the complex interplay of the actions of both the template and the activating agent as well. On the other hand, zeolite-made template shapes allowed for the preparation of microporous carbon monoliths with a high volumetric specific surface area. This feature could be beneficial if carbon monoliths must be integrated into technical systems under space-limited conditions.

Synthesis of Porous Carbon Monoliths Using Hard Templates

PubMed Central

Klepel, Olaf; Danneberg, Nina; Dräger, Matti; Erlitz, Marcel; Taubert, Michael

2016-01-01

The preparation of porous carbon monoliths with a defined shape via template-assisted routes is reported. Monoliths made from porous concrete and zeolite were each used as the template. The porous concrete-derived carbon monoliths exhibited high gravimetric specific surface areas up to 2000 m2·g−1. The pore system comprised macro-, meso-, and micropores. These pores were hierarchically arranged. The pore system was created by the complex interplay of the actions of both the template and the activating agent as well. On the other hand, zeolite-made template shapes allowed for the preparation of microporous carbon monoliths with a high volumetric specific surface area. This feature could be beneficial if carbon monoliths must be integrated into technical systems under space-limited conditions. PMID:28773338

Advanced Propfan Engine Technology (APET) and Single-rotation Gearbox/Pitch Change Mechanism

NASA Technical Reports Server (NTRS)

Sargisson, D. F.

1985-01-01

The projected performance, in the 1990's time period, of the equivalent technology level high bypass ratio turbofan powered aircraft (at the 150 passenger size) is compared with advanced turboprop propulsion systems. Fuel burn analysis, economic analysis, and pollution (noise, emissions) estimates were made. Three different cruise Mach numbers were investigated for both the turbofan and the turboprop systems. Aerodynamic design and performance estimates were made for nacelles, inlets, and exhaust systems. Air to oil heat exchangers were investigated for oil cooling advanced gearboxes at the 12,500 SHP level. The results and conclusions are positive in that high speed turboprop aircraft will exhibit superior fuel burn characteristics and lower operating costs when compared with equivalent technology turbofan aircraft.

Intermittent impact dynamics of a cantilever scanning a surface at high speed

NASA Astrophysics Data System (ADS)

Dey, S.; Kartik, V.

2018-03-01

In contact-mode scanning probe microscopy (SPM), the cantilever's dynamics are conventionally investigated by assuming the tip to be always in contact with the sample's surface. At high scanning speeds, however, the cantilever's inertia becomes dominant and the tip can therefore completely detach from the surface and start impacting upon it. Experiments at the macro-scale cannot emulate the complex micro-scale dynamics, as the system exhibits negligible effects due to meniscus forces and the surrounding medium's squeeze film damping; however, they can provide qualitative insight into the cantilever's dynamics at high frequencies, corresponding to those likely to be excited during video-rate SPM imaging. This paper investigates such intermittent impact dynamics for an upscaled cantilever, analytically, numerically, and experimentally. In contact-mode scanning, a critical scan speed exists beyond which the cantilever's tip loses contact with the sample's surface; a closed-form expression for this contact loss frequency is derived. At high scan speeds, impacts cause the cantilever to switch between different contact regimes: in-, off-, and grazing-contact; within each regime, the system's modal configuration is different. Experimentally-obtained Poincare maps indicate quasi-periodic behaviour at frequencies for which the response is repetitive, as is also predicted by the model. Intermittent impacts excite the sub- and super-harmonics of the excitation frequency, which are related to the natural frequencies of different system configurations based on the "effective" tip-end boundary conditions. The cantilever's response exhibits several phenomena, such as modal transition, beating, grazing, and possible chaotic behaviour, depending upon the relation between the excitation harmonics and the natural frequencies.

Large-eddy simulations of the restricted nonlinear system

NASA Astrophysics Data System (ADS)

Bretheim, Joel; Gayme, Dennice; Meneveau, Charles

2014-11-01

Wall-bounded shear flows often exhibit elongated flow structures with streamwise coherence (e.g. rolls/streaks), prompting the exploration of a streamwise-constant modeling framework to investigate wall-turbulence. Simulations of a streamwise-constant (2D/3C) model have been shown to produce the roll/streak structures and accurately reproduce the blunted turbulent mean velocity profile in plane Couette flow. The related restricted nonlinear (RNL) model captures these same features but also exhibits self-sustaining turbulent behavior. Direct numerical simulation (DNS) of the RNL system results in similar statistics for a number of flow quantities and a flow field that is consistent with DNS of the Navier-Stokes equations. Aiming to develop reduced-order models of wall-bounded turbulence at very high Reynolds numbers in which viscous near-wall dynamics cannot be resolved, this work presents the development of an RNL formulation of the filtered Navier-Stokes equations solved for in large-eddy simulations (LES). The proposed LES-RNL system is a computationally affordable reduced-order modeling tool that is of interest for studying the underlying dynamics of high-Reynolds wall-turbulence and for engineering applications where the flow field is dominated by streamwise-coherent motions. This work is supported by NSF (IGERT, SEP-1230788 and IIA-1243482).

Comfortable, high-efficiency heat pump with desiccant-coated, water-sorbing heat exchangers

PubMed Central

Tu, Y. D.; Wang, R. Z.; Ge, T. S.; Zheng, X.

2017-01-01

Comfortable, efficient, and affordable heating, ventilation, and air conditioning systems in buildings are highly desirable due to the demands of energy efficiency and environmental friendliness. Traditional vapor-compression air conditioners exhibit a lower coefficient of performance (COP) (typically 2.8–3.8) owing to the cooling-based dehumidification methods that handle both sensible and latent loads together. Temperature- and humidity-independent control or desiccant systems have been proposed to overcome these challenges; however, the COP of current desiccant systems is quite small and additional heat sources are usually needed. Here, we report on a desiccant-enhanced, direct expansion heat pump based on a water-sorbing heat exchanger with a desiccant coating that exhibits an ultrahigh COP value of more than 7 without sacrificing any comfort or compactness. The pump’s efficiency is doubled compared to that of pumps currently used in conventional room air conditioners, which is a revolutionary HVAC breakthrough. Our proposed water-sorbing heat exchanger can independently handle sensible and latent loads at the same time. The desiccants adsorb moisture almost isothermally and can be regenerated by condensation heat. This new approach opens up the possibility of achieving ultrahigh efficiency for a broad range of temperature- and humidity-control applications. PMID:28079171

Malicious Hubs: Detecting Abnormally Malicious Autonomous Systems

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

Kalafut, Andrew J.; Shue, Craig A; Gupta, Prof. Minaxi

While many attacks are distributed across botnets, investigators and network operators have recently targeted malicious networks through high profile autonomous system (AS) de-peerings and network shut-downs. In this paper, we explore whether some ASes indeed are safe havens for malicious activity. We look for ISPs and ASes that exhibit disproportionately high malicious behavior using 12 popular blacklists. We find that some ASes have over 80% of their routable IP address space blacklisted and others account for large fractions of blacklisted IPs. Overall, we conclude that examining malicious activity at the AS granularity can unearth networks with lax security or thosemore » that harbor cybercrime.« less

Large-Scale Simulation of Multi-Asset Ising Financial Markets

NASA Astrophysics Data System (ADS)

Takaishi, Tetsuya

2017-03-01

We perform a large-scale simulation of an Ising-based financial market model that includes 300 asset time series. The financial system simulated by the model shows a fat-tailed return distribution and volatility clustering and exhibits unstable periods indicated by the volatility index measured as the average of absolute-returns. Moreover, we determine that the cumulative risk fraction, which measures the system risk, changes at high volatility periods. We also calculate the inverse participation ratio (IPR) and its higher-power version, IPR6, from the absolute-return cross-correlation matrix. Finally, we show that the IPR and IPR6 also change at high volatility periods.

Femtosecond Laser Eyewear Protection: Measurements and Precautions

PubMed Central

Stromberg, Christopher J.; Hadler, Joshua A.; Alberding, Brian G.; Heilweil, Edwin J.

2018-01-01

Ultrafast laser systems are becoming more widespread throughout the research and industrial communities yet eye protection for these high power, bright pulsed sources still require scrupulous characterization and testing before use. Femtosecond lasers, with pulses naturally possessing broad-bandwidth and high average power with variable repetition rate, can exhibit spectral side-bands and subtly changing center wavelengths, which may unknowingly affect eyewear safety protection. Pulse spectral characterization and power diagnostics are presented for a 80 MHz, Ti+3:Sapphire, ≈ 800 nm, ≈40 femtosecond oscillator system. Power and spectral transmission for 22 test samples are measured to determine whether they fall within manufacturer specifications. PMID:29353984

Femtosecond Laser Eyewear Protection: Measurements and Precautions.

PubMed

Stromberg, Christopher J; Hadler, Joshua A; Alberding, Brian G; Heilweil, Edwin J

2017-11-01

Ultrafast laser systems are becoming more widespread throughout the research and industrial communities yet eye protection for these high power, bright pulsed sources still require scrupulous characterization and testing before use. Femtosecond lasers, with pulses naturally possessing broad-bandwidth and high average power with variable repetition rate, can exhibit spectral side-bands and subtly changing center wavelengths, which may unknowingly affect eyewear safety protection. Pulse spectral characterization and power diagnostics are presented for a 80 MHz, Ti +3 :Sapphire, ≈ 800 nm, ≈40 femtosecond oscillator system. Power and spectral transmission for 22 test samples are measured to determine whether they fall within manufacturer specifications.

A Study of the Kepler K2 Variable EPIC 211957146 Exhibiting a Variable O’ Connell Effect

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

Sriram, K.; Malu, S.; Rao, P. Vivekananda

We present the multi-band photometric and spectroscopic study of an over-contact binary system, EPIC 211957146. The light curves exhibit a variable O’ Connell effect, confirmed from our observational data and the Kepler K2 data. The best photometric solution incorporating a dark spot over the primary component unveils that the system has a low-mass ratio ( q  ∼ 0.17) and a high inclination ( i  ∼ 85°). To confirm the solution and constrain the uncertainty, Monte-Carlo simulations are performed and the results are reported. Based on the O–C diagram analysis, we see that the variable shows a period increase at the rate ofmore » dP / dt  ∼ 1.06 × 10{sup −6} days yr{sup −1}, which is higher than the theoretically predicted value. Presence of a third body having a period of ∼16.23 years is evident from the O–C diagram. No filled-in effect is observed in the H α line, while the effect is vividly present in the Na line. From the Kepler K2 data, we found that the primary and secondary minima exhibit an anti-correlated O–C variation followed by an erratic behavior. This is possibly caused by the longitudinal motion of the spot, and hence, we set a lower limit of ∼40 days for the spot modulation. We also observe a possibly associated photometric difference in the primary depth by comparing our light curves with Kepler K2 normalized light curves. This system has a low-mass ratio and a high fill-out factor, and, theoretically, such a physical configuration would lead to a merger.« less

A Study of the Kepler K2 Variable EPIC 211957146 Exhibiting a Variable O’ Connell Effect

NASA Astrophysics Data System (ADS)

Sriram, K.; Malu, S.; Choi, C. S.; Vivekananda Rao, P.

2017-05-01

We present the multi-band photometric and spectroscopic study of an over-contact binary system, EPIC 211957146. The light curves exhibit a variable O’ Connell effect, confirmed from our observational data and the Kepler K2 data. The best photometric solution incorporating a dark spot over the primary component unveils that the system has a low-mass ratio (q ˜ 0.17) and a high inclination (I ˜ 85°). To confirm the solution and constrain the uncertainty, Monte-Carlo simulations are performed and the results are reported. Based on the O-C diagram analysis, we see that the variable shows a period increase at the rate of dP/dt ˜ 1.06 × 10-6 days yr-1, which is higher than the theoretically predicted value. Presence of a third body having a period of ˜16.23 years is evident from the O-C diagram. No filled-in effect is observed in the Hα line, while the effect is vividly present in the Na line. From the Kepler K2 data, we found that the primary and secondary minima exhibit an anti-correlated O-C variation followed by an erratic behavior. This is possibly caused by the longitudinal motion of the spot, and hence, we set a lower limit of ˜40 days for the spot modulation. We also observe a possibly associated photometric difference in the primary depth by comparing our light curves with Kepler K2 normalized light curves. This system has a low-mass ratio and a high fill-out factor, and, theoretically, such a physical configuration would lead to a merger.

Highly Stereoselective Intermolecular Haloetherification and Haloesterification of Allyl Amides

PubMed Central

Soltanzadeh, Bardia; Jaganathan, Arvind; Staples, Richard J.

2016-01-01

An organocatalytic and highly regio-, diastereo-, and enantioselective intermolecular haloetherification and haloesterification reaction of allyl amides is reported. A variety of alkene substituents and substitution patterns are compatible with this chemistry. Notably, electronically unbiased alkene substrates exhibit exquisite regio- and diastereoselectivity for the title transformation. We also demonstrate that the same catalytic system can be used in both chlorination and bromination reactions of allyl amides with a variety of nucleophiles with little or no modification. PMID:26110812

An Ultrastable Europium(III)-Organic Framework with the Capacity of Discriminating Fe2+/Fe3+ Ions in Various Solutions.

PubMed

Wen, Guo-Xuan; Wu, Ya-Pan; Dong, Wen-Wen; Zhao, Jun; Li, Dong-Sheng; Zhang, Jian

2016-10-05

An ultrastable luminescent europium-organic framework, {[Eu(L)(H 2 O) 2 ]·NMP·H 2 O} n (CTGU-2; NMP = N-methyl-2-pyrrolidone), can first detect Fe 2+ /Fe 3+ cations in different medium systems with high selectivity and sensitivity, and it also exhibits high sensitivity for Cr 2 O 7 2- anion and acetone with a wide linear range and a low detection limit.

Developing a reversible rapid coordinate transformation model for the cylindrical projection

NASA Astrophysics Data System (ADS)

Ye, Si-jing; Yan, Tai-lai; Yue, Yan-li; Lin, Wei-yan; Li, Lin; Yao, Xiao-chuang; Mu, Qin-yun; Li, Yong-qin; Zhu, De-hai

2016-04-01

Numerical models are widely used for coordinate transformations. However, in most numerical models, polynomials are generated to approximate "true" geographic coordinates or plane coordinates, and one polynomial is hard to make simultaneously appropriate for both forward and inverse transformations. As there is a transformation rule between geographic coordinates and plane coordinates, how accurate and efficient is the calculation of the coordinate transformation if we construct polynomials to approximate the transformation rule instead of "true" coordinates? In addition, is it preferable to compare models using such polynomials with traditional numerical models with even higher exponents? Focusing on cylindrical projection, this paper reports on a grid-based rapid numerical transformation model - a linear rule approximation model (LRA-model) that constructs linear polynomials to approximate the transformation rule and uses a graticule to alleviate error propagation. Our experiments on cylindrical projection transformation between the WGS 84 Geographic Coordinate System (EPSG 4326) and the WGS 84 UTM ZONE 50N Plane Coordinate System (EPSG 32650) with simulated data demonstrate that the LRA-model exhibits high efficiency, high accuracy, and high stability; is simple and easy to use for both forward and inverse transformations; and can be applied to the transformation of a large amount of data with a requirement of high calculation efficiency. Furthermore, the LRA-model exhibits advantages in terms of calculation efficiency, accuracy and stability for coordinate transformations, compared to the widely used hyperbolic transformation model.

An infrared optical pacing system for screening cardiac electrophysiology in human cardiomyocytes.

PubMed

McPheeters, Matthew T; Wang, Yves T; Werdich, Andreas A; Jenkins, Michael W; Laurita, Kenneth R

2017-01-01

Human cardiac myocytes derived from pluripotent stem cells (hCM) have invigorated interest in genetic disease mechanisms and cardiac safety testing; however, the technology to fully assess electrophysiological function in an assay that is amenable to high throughput screening has lagged. We describe a fully contactless system using optical pacing with an infrared (IR) laser and multi-site high fidelity fluorescence imaging to assess multiple electrophysiological parameters from hCM monolayers in a standard 96-well plate. Simultaneous multi-site action potentials (FluoVolt) or Ca2+ transients (Fluo4-AM) were measured, from which high resolution maps of conduction velocity and action potential duration (APD) were obtained in a single well. Energy thresholds for optical pacing were determined for cell plating density, laser spot size, pulse width, and wavelength and found to be within ranges reported previously for reliable pacing. Action potentials measured using FluoVolt and a microelectrode exhibited the same morphology and rate of depolarization. Importantly, we show that this can be achieved accurately with minimal damage to hCM due to optical pacing or fluorescence excitation. Finally, using this assay we demonstrate that hCM exhibit reproducible changes in repolarization and impulse conduction velocity for Flecainide and Quinidine, two well described reference compounds. In conclusion, we demonstrate a high fidelity electrophysiological screening assay that incorporates optical pacing with IR light to control beating rate of hCM monolayers.

System-Level Design of a Shape Memory Alloy Actuator for Active Clearance Control in the High-Pressure Turbine

NASA Technical Reports Server (NTRS)

DeCastro, Jonathan A.; Melcher, Kevin J.; Noebe, Ronald D.

2005-01-01

This paper describes results of a numerical analysis evaluating the feasibility of high-temperature shape memory alloys (HTSMA) for active clearance control actuation in the high-pressure turbine section of a modern turbofan engine. The prototype actuator concept considered here consists of parallel HTSMA wires attached to the shroud that is located on the exterior of the turbine case. A transient model of an HTSMA actuator was used to evaluate active clearance control at various operating points in a test bed aircraft engine simulation. For the engine under consideration, each actuator must be designed to counteract loads from 380 to 2000 lbf and displace at least 0.033 inches. Design results show that an actuator comprised of 10 wires 2 inches in length is adequate for control at critical engine operating points and still exhibits acceptable failsafe operability and cycle life. A proportional-integral-derivative (PID) controller with integrator windup protection was implemented to control clearance amidst engine transients during a normal mission. Simulation results show that the control system exhibits minimal variability in clearance control performance across the operating envelope. The final actuator design is sufficiently small to fit within the limited space outside the high-pressure turbine case and is shown to consume only small amounts of bleed air to adequately regulate temperature.

Interesting examples of supervised continuous variable systems

NASA Technical Reports Server (NTRS)

Chase, Christopher; Serrano, Joe; Ramadge, Peter

1990-01-01

The authors analyze two simple deterministic flow models for multiple buffer servers which are examples of the supervision of continuous variable systems by a discrete controller. These systems exhibit what may be regarded as the two extremes of complexity of the closed loop behavior: one is eventually periodic, the other is chaotic. The first example exhibits chaotic behavior that could be characterized statistically. The dual system, the switched server system, exhibits very predictable behavior, which is modeled by a finite state automaton. This research has application to multimodal discrete time systems where the controller can choose from a set of transition maps to implement.

High-speed railway real-time localization auxiliary method based on deep neural network

NASA Astrophysics Data System (ADS)

Chen, Dongjie; Zhang, Wensheng; Yang, Yang

2017-11-01

High-speed railway intelligent monitoring and management system is composed of schedule integration, geographic information, location services, and data mining technology for integration of time and space data. Assistant localization is a significant submodule of the intelligent monitoring system. In practical application, the general access is to capture the image sequences of the components by using a high-definition camera, digital image processing technique and target detection, tracking and even behavior analysis method. In this paper, we present an end-to-end character recognition method based on a deep CNN network called YOLO-toc for high-speed railway pillar plate number. Different from other deep CNNs, YOLO-toc is an end-to-end multi-target detection framework, furthermore, it exhibits a state-of-art performance on real-time detection with a nearly 50fps achieved on GPU (GTX960). Finally, we realize a real-time but high-accuracy pillar plate number recognition system and integrate natural scene OCR into a dedicated classification YOLO-toc model.

Interfacing planar superconducting qubits with high overtone bulk acoustic phonons

NASA Astrophysics Data System (ADS)

Kervinen, Mikael; Rissanen, Ilkka; Sillanpää, Mika

2018-05-01

Mechanical resonators are a promising way for interfacing qubits in order to realize hybrid quantum systems that offer great possibilities for applications. Mechanical systems can have very long energy lifetimes, and they can be further interfaced to other systems. Moreover, integration of a mechanical oscillator with qubits creates a potential platform for the exploration of quantum physics in macroscopic mechanical degrees of freedom. The utilization of high overtone bulk acoustic resonators coupled to superconducting qubits is an intriguing platform towards these goals. These resonators exhibit a combination of high-frequency and high-quality factors. They can reach their quantum ground state at dilution refrigeration temperatures and they can be strongly coupled to superconducting qubits via their piezoelectric effect. In this paper, we demonstrate our system where bulk acoustic phonons of a high overtone resonator are coupled to a transmon qubit in a planar circuit architecture. We show that the bulk acoustic phonons are interacting with the qubit in a simple design architecture at the quantum level, representing further progress towards the quantum control of mechanical motion.

Magnetostrictive performance of additively manufactured CoFe rods using the LENS (TM) system

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

Jones, Nicholas J.; Yoo, Jin-Hyeong; Ott, Ryan T.

Magnetostrictive materials exhibit a strain in the presence of a variable magnetic field. While they normally require large, highly oriented crystallographic grains for high strain values, metal additive manufacturing (3D printing) may be able to produce highly textured polycrystalline rods, with properties comparable to those manufactured using the more demanding free standing zone melting (FSZM) technique. Rods of Co 75.8Fe 24.2 and Co 63.7Fe 36.3 have been fabricated using the Laser engineered net shaping (LENS TM) system to evaluate the performance of additively manufactured magnetic and magnetostrictive materials. The 76% Co sample showed an average magnetostriction (λ) of 86 ppmmore » at a stress of 124 MPa; in contrast, the 64% Co sample showed only 27 ppm at the same stress. For direct comparison, a Co 67Fe 33 single crystal disk, also measured as part of this study, exhibited a magnetostriction value of 131 and 91 microstrain in the [100] and [111] directions, respectively, with a calculated polycrystalline value (λ s) of 107 microstrain. Electron back scattered diffraction (EBSD) has been used to qualitatively link the performance with crystallographic orientation and phase information, showing only the BCC phase in the 76% Co sample, but three different phases (BCC, FCC, and HCP) in the 64% Co sample.« less

Magnetostrictive performance of additively manufactured CoFe rods using the LENSTM system

NASA Astrophysics Data System (ADS)

Jones, Nicholas J.; Yoo, Jin-Hyeong; Ott, Ryan T.; Lambert, Paul K.; Petculescu, Gabriela; Simsek, Emrah; Schlagel, Deborah; Lograsso, Thomas A.

2018-05-01

Magnetostrictive materials exhibit a strain in the presence of a variable magnetic field. While they normally require large, highly oriented crystallographic grains for high strain values, metal additive manufacturing (3D printing) may be able to produce highly textured polycrystalline rods, with properties comparable to those manufactured using the more demanding free standing zone melting (FSZM) technique. Rods of Co75.8Fe24.2 and Co63.7Fe36.3 have been fabricated using the Laser engineered net shaping (LENSTM) system to evaluate the performance of additively manufactured magnetic and magnetostrictive materials. The 76% Co sample showed an average magnetostriction (λ) of 86 ppm at a stress of 124 MPa; in contrast, the 64% Co sample showed only 27 ppm at the same stress. For direct comparison, a Co67Fe33 single crystal disk, also measured as part of this study, exhibited a magnetostriction value of 131 and 91 microstrain in the [100] and [111] directions, respectively, with a calculated polycrystalline value (λs) of 107 microstrain. Electron back scattered diffraction (EBSD) has been used to qualitatively link the performance with crystallographic orientation and phase information, showing only the BCC phase in the 76% Co sample, but three different phases (BCC, FCC, and HCP) in the 64% Co sample.

Magnetostrictive performance of additively manufactured CoFe rods using the LENS (TM) system

DOE PAGES

Jones, Nicholas J.; Yoo, Jin-Hyeong; Ott, Ryan T.; ...

2018-05-01

Magnetostrictive materials exhibit a strain in the presence of a variable magnetic field. While they normally require large, highly oriented crystallographic grains for high strain values, metal additive manufacturing (3D printing) may be able to produce highly textured polycrystalline rods, with properties comparable to those manufactured using the more demanding free standing zone melting (FSZM) technique. Rods of Co 75.8Fe 24.2 and Co 63.7Fe 36.3 have been fabricated using the Laser engineered net shaping (LENS TM) system to evaluate the performance of additively manufactured magnetic and magnetostrictive materials. The 76% Co sample showed an average magnetostriction (λ) of 86 ppmmore » at a stress of 124 MPa; in contrast, the 64% Co sample showed only 27 ppm at the same stress. For direct comparison, a Co 67Fe 33 single crystal disk, also measured as part of this study, exhibited a magnetostriction value of 131 and 91 microstrain in the [100] and [111] directions, respectively, with a calculated polycrystalline value (λ s) of 107 microstrain. Electron back scattered diffraction (EBSD) has been used to qualitatively link the performance with crystallographic orientation and phase information, showing only the BCC phase in the 76% Co sample, but three different phases (BCC, FCC, and HCP) in the 64% Co sample.« less

Spatiotemporal Co-variability of Surface Climate for Renewable Energy across the Contiguous United States: Role of the North Atlantic Subtropical High

NASA Astrophysics Data System (ADS)

Doering, K.; Steinschneider, S.

2017-12-01

The variability of renewable energy supply and drivers of demand across space and time largely determines the energy balance within power systems with a high penetration of renewable technologies. This study examines the joint spatiotemporal variability of summertime climate linked to renewable energy production (precipitation, wind speeds, insolation) and energy demand (temperature) across the contiguous United States (CONUS) between 1948 and 2015. Canonical correlation analysis is used to identify the major modes of joint variability between summer wind speeds and precipitation and related patterns of insolation and temperature. Canonical variates are then related to circulation anomalies to identify common drivers of the joint modes of climate variability. Results show that the first two modes of joint variability between summer wind speeds and precipitation exhibit pan-US dipole patterns with centers of action located in the eastern and central CONUS. Temperature and insolation also exhibit related US-wide dipoles. The relationship between canonical variates and lower-tropospheric geopotential height indicates that these modes are related to variability in the North Atlantic subtropical high (NASH). This insight can inform optimal strategies for siting renewables in an interconnected electric grid, and has implications for the impacts of climate variability and change on renewable energy systems.

Hard X-Ray Lightcurves of High Mass X-Ray Binaries

NASA Technical Reports Server (NTRS)

Laycock, S.; Coe, M. J.; Harmon, B. A.; Finger, M.; Wilson-Hodge, C.; Rose, M. Franklin (Technical Monitor)

2001-01-01

Using the 7.2 years of continuous data now available from the Burst And Transient Source Experiment (BATSE) aboard CGRO, we have measured orbital periods and produced folded lightcurves for 8 High Mass X-ray Binaries (HMXB). Given the length of the datasets, our determinations are based on many more binary orbits than previous investigations. Thus our source detections have high statistical significance and we are able to follow long-term trends in X-ray output. In particular we focus on two systems: A0538-668 and EXO2030+375 both HMXBs exhibiting Type I outbursts. Recent work on A0538-668 (Alcock et al 1999) reported a 16.65d optical variability due to the orbital period, but only seen during minima of a longer-term variability at 421d. We searched for this signal in the BATSE dataset using an ephemeris derived from Alcock et al ( 1999) & Skinner ( 1982). We found no evidence for such modulation and place an upper limit of 3.0 x 10(exp -3) photon/sq cm.s in the 20-70 keV BATSE energy band , based upon statistical modelling of the signal. EXO2030+375 has exhibited an X-ray active epoch, followed by a quiescent period lasting 2.5yr and since April 1996 has exhibited renewed activity. Previous observations (Reig et a 1998) using RXTE ASM data indicate secondary outbursts occur at apastron passage during the current epoch, but not in the former. We present a lightcurve for the earlier epoch showing convincing evidence for such apastron outbursts. We find apastron outbursts in 3 sources, all having orbital periods greater than 41d. No such signal is conclusively detected in the more rapidly orbiting systems studied.

A detailed investigation of the strain hardening response of aluminum alloyed Hadfield steel

NASA Astrophysics Data System (ADS)

Canadinc, Demircan

The unusual strain hardening response exhibited by Hadfield steel single and polycrystals under tensile loading was investigated. Hadfield steel, which deforms plastically through the competing mechanisms slip and twinning, was alloyed with aluminum in order to suppress twinning and study the role of slip only. To avoid complications due to a grained structure, only single crystals of the aluminum alloyed Hadfield steel were considered at the initial stage of the current study. As a result of alloying with aluminum, twinning was suppressed; however a significant increase in the strain hardening response was also present. A detailed microstructural analysis showed the presence of high-density dislocation walls that evolve in volume fraction due to plastic deformation and interaction with slip systems. The very high strain hardening rates exhibited by the aluminum alloyed Hadfield steel single crystals was attributed to the blockage of glide dislocations by the high-density dislocation walls. A crystal plasticity model was proposed, that accounts for the volume fraction evolution and rotation of the dense dislocation walls, as well as their interaction with the active slip systems. The novelty of the model lies in the simplicity of the constitutive equations that define the strain hardening, and the fact that it is based on experimental data regarding the microstructure. The success of the model was tested by its application to different crystallographic orientations, and finally the polycrystals of the aluminum alloyed Hadfield steel. Meanwhile, the capability of the model to predict texture was also observed through the rotation of the loading axis in single crystals. The ability of the model to capture the polycrystalline deformation response provides a venue for its utilization in other alloys that exhibit dislocation sheet structures.

Response Characteristics of a Stable Mixed Potential Ammonia Sensor in Simulated Diesel Exhaust

DOE PAGES

Ramaiyan, Kannan P.; Pihl, Josh A.; Kreller, Cortney R.; ...

2017-07-15

A mixed potential sensor using Au and Pt dense wire electrodes embedded between tape-casted layers of 8 mol% yttria stabilized zirconia (YSZ) was tested for application toward NH 3, NO, NO 2, C 3H 6 and C 3H 8. In single-gas testing, the sensor exhibited the highest response toward NH 3, while still exhibiting reasonably high sensitivity toward other interferent gases. We tested the sensor in a high-flow reactor at the National Transportation Research Center (NTRC) in order to simulate exhaust gas constituents and flow rates produced by lean-burn vehicles powered by Compression-Ignition Direct-Injection (CIDI), diesel engines. The sensor wasmore » characterized at 525 and 625°C for NH 3, CO, C 3H 6, C 3H 8, and NO x in a base gas composition of 10% O 2, 5% H 2O, and 5% CO 2 flowing at 15 slpm. The sensor exhibited fast response time equal to the response time of the system's switching valve (T90<0.6s). Furthermore, in simulations of overdosing a selective catalytic reduction (SCR) system, the sensor was able to selectively respond to 20ppm injections of NH 3 slip despite the presence of the interferent gas species at combined concentrations ten times higher than that of the NH 3. The laboratory sensor construct was transitioned to a pre-commercial, automotive stick sensor configuration that was demonstrated to retain the advantageous characteristics of the tape-cast device.« less

Response Characteristics of a Stable Mixed Potential Ammonia Sensor in Simulated Diesel Exhaust

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

Ramaiyan, Kannan P.; Pihl, Josh A.; Kreller, Cortney R.

A mixed potential sensor using Au and Pt dense wire electrodes embedded between tape-casted layers of 8 mol% yttria stabilized zirconia (YSZ) was tested for application toward NH 3, NO, NO 2, C 3H 6 and C 3H 8. In single-gas testing, the sensor exhibited the highest response toward NH 3, while still exhibiting reasonably high sensitivity toward other interferent gases. We tested the sensor in a high-flow reactor at the National Transportation Research Center (NTRC) in order to simulate exhaust gas constituents and flow rates produced by lean-burn vehicles powered by Compression-Ignition Direct-Injection (CIDI), diesel engines. The sensor wasmore » characterized at 525 and 625°C for NH 3, CO, C 3H 6, C 3H 8, and NO x in a base gas composition of 10% O 2, 5% H 2O, and 5% CO 2 flowing at 15 slpm. The sensor exhibited fast response time equal to the response time of the system's switching valve (T90<0.6s). Furthermore, in simulations of overdosing a selective catalytic reduction (SCR) system, the sensor was able to selectively respond to 20ppm injections of NH 3 slip despite the presence of the interferent gas species at combined concentrations ten times higher than that of the NH 3. The laboratory sensor construct was transitioned to a pre-commercial, automotive stick sensor configuration that was demonstrated to retain the advantageous characteristics of the tape-cast device.« less

Thermoregulation of Capsule Production by Streptococcus pyogenes

PubMed Central

Kang, Song Ok; Wright, Jordan O.; Tesorero, Rafael A.; Lee, Hyunwoo; Beall, Bernard; Cho, Kyu Hong

2012-01-01

The capsule of Streptococcus pyogenes serves as an adhesin as well as an anti-phagocytic factor by binding to CD44 on keratinocytes of the pharyngeal mucosa and the skin, the main entry sites of the pathogen. We discovered that S. pyogenes HSC5 and MGAS315 strains are further thermoregulated for capsule production at a post-transcriptional level in addition to the transcriptional regulation by the CovRS two-component regulatory system. When the transcription of the hasABC capsular biosynthetic locus was de-repressed through mutation of the covRS system, the two strains, which have been used for pathogenesis studies in the laboratory, exhibited markedly increased capsule production at sub-body temperature. Employing transposon mutagenesis, we found that CvfA, a previously identified membrane-associated endoribonuclease, is required for the thermoregulation of capsule synthesis. The mutation of the cvfA gene conferred increased capsule production regardless of temperature. However, the amount of the capsule transcript was not changed by the mutation, indicating that a post-transcriptional regulator mediates between CvfA and thermoregulated capsule production. When we tested naturally occurring invasive mucoid strains, a high percentage (11/53, 21%) of the strains exhibited thermoregulated capsule production. As expected, the mucoid phenotype of these strains at sub-body temperature was due to mutations within the chromosomal covRS genes. Capsule thermoregulation that exhibits high capsule production at lower temperatures that occur on the skin or mucosal surface potentially confers better capability of adhesion and invasion when S. pyogenes penetrates the epithelial surface. PMID:22615992

High-performance nanostructured supercapacitors on a sponge.

PubMed

Chen, Wei; Rakhi, R B; Hu, Liangbing; Xie, Xing; Cui, Yi; Alshareef, H N

2011-12-14

A simple and scalable method has been developed to fabricate nanostructured MnO2-carbon nanotube (CNT)-sponge hybrid electrodes. A novel supercapacitor, henceforth referred to as "sponge supercapacitor", has been fabricated using these hybrid electrodes with remarkable performance. A specific capacitance of 1,230 F/g (based on the mass of MnO2) can be reached. Capacitors based on CNT-sponge substrates (without MnO2) can be operated even under a high scan rate of 200 V/s, and they exhibit outstanding cycle performance with only 2% degradation after 100,000 cycles under a scan rate of 10 V/s. The MnO2-CNT-sponge supercapacitors show only 4% of degradation after 10,000 cycles at a charge-discharge specific current of 5 A/g. The specific power and energy of the MnO2-CNT-sponge supercapacitors are high with values of 63 kW/kg and 31 Wh/kg, respectively. The attractive performances exhibited by these sponge supercapacitors make them potentially promising candidates for future energy storage systems.

Spatiotemporal noise characterization for chirped-pulse amplification systems

PubMed Central

Ma, Jingui; Yuan, Peng; Wang, Jing; Wang, Yongzhi; Xie, Guoqiang; Zhu, Heyuan; Qian, Liejia

2015-01-01

Optical noise, the core of the pulse-contrast challenge for ultra-high peak power femtosecond lasers, exhibits spatiotemporal (ST) coupling induced by angular dispersion. Full characterization of such ST noise requires two-dimensional measurements in the ST domain. Thus far, all noise measurements have been made only in the temporal domain. Here we report the experimental characterization of the ST noise, which is made feasible by extending cross-correlation from the temporal domain to the ST domain. We experimentally demonstrate that the ST noise originates from the optical surface imperfections in the pulse stretcher/compressor and exhibits a linear ST coupling in the far-field plane. The contrast on the far-field axis, underestimated in the conventional measurements, is further improved by avoiding the far-field optics in the stretcher. These results enhance our understanding of the pulse contrast with respect to its ST-coupling nature and pave the way toward the design of high-contrast ultra-high peak power lasers. PMID:25648187

Thermoelectric properties and performance of flexible reduced graphene oxide films up to 3,000 K

NASA Astrophysics Data System (ADS)

Li, Tian; Pickel, Andrea D.; Yao, Yonggang; Chen, Yanan; Zeng, Yuqiang; Lacey, Steven D.; Li, Yiju; Wang, Yilin; Dai, Jiaqi; Wang, Yanbin; Yang, Bao; Fuhrer, Michael S.; Marconnet, Amy; Dames, Chris; Drew, Dennis H.; Hu, Liangbing

2018-02-01

The development of ultrahigh-temperature thermoelectric materials could enable thermoelectric topping of combustion power cycles as well as extending the range of direct thermoelectric power generation in concentrated solar power. However, thermoelectric operation temperatures have been restricted to under 1,500 K due to the lack of suitable materials. Here, we demonstrate a thermoelectric conversion material based on high-temperature reduced graphene oxide nanosheets that can perform reliably up to 3,000 K. After a reduction treatment at 3,300 K, the nanosheet film exhibits an increased conductivity to 4,000 S cm-1 at 3,000 K and a high power factor S2σ = 54.5 µW cm-1 K-2. We report measurements characterizing the film's thermoelectric properties up to 3,000 K. The reduced graphene oxide film also exhibits a high broadband radiation absorbance and can act as both a radiative receiver and a thermoelectric generator. The printable, lightweight and flexible film is attractive for system integration and scalable manufacturing.

Silicon/copper dome-patterned electrodes for high-performance hybrid supercapacitors

PubMed Central

Liu, Xuyan; Jung, Hun-Gi; Kim, Sang-Ok; Choi, Ho-Suk; Lee, Sangwha; Moon, Jun Hyuk; Lee, Joong Kee

2013-01-01

This study proposes a method for manufacturing high-performance electrode materials in which controlling the shape of the current collector and electrode material for a Li-ion capacitor (LIC). In particular, the proposed LIC manufacturing method maintains the high voltage of a cell by using a microdome-patterned electrode material, allowing for reversible reactions between the Li-ion and the active material for an extended period of time. As a result, the LICs exhibit initial capacities of approximately 42 F g−1, even at 60 A g−1. The LICs also exhibit good cycle performance up to approximately 15,000 cycles. In addition, these advancements allow for a considerably higher energy density than other existing capacitor systems. The energy density of the proposed LICs is approximately nine, two, and 1.5 times higher than those of the electrochemical double layer capacitor (EDLC), AC/LiMn2O4 hybrid capacitor, and intrinsic Si/AC LIC, respectively. PMID:24292725

HIGH-ENERGY PULSED LIQUID LASER.

DTIC Science & Technology

SeOCl2:SnCl4, POCL3:SnCl4 and POCL3: ZrCl4 , are presented in detail. It is shown from the point of view of gain, efficiency and loss, that the first and...third systems are equivalent, while the second exhibits some degree of solubility instability. Chemically, the POCL3: ZrCl4 represents a significant

Redundant Information and the Quantum-Classical Transition

ERIC Educational Resources Information Center

Riedel, Charles Jess

2012-01-01

A state selected at random from the Hilbert space of a many-body system is overwhelmingly likely to exhibit highly non-classical correlations. For these typical states, half of the environment must be measured by an observer to determine the state of a given subsystem. The objectivity of classical reality--the fact that multiple observers can each…

Impregnation of bio-oil from small diameter pine into wood for moisture resistance

Treesearch

Thomas J. Robinson; Brian K. Via; Oladiran Fasina; Sushil Adhikari; Emily Carter

2011-01-01

Wood pyrolysis oil consists of hundreds of complex compounds, many of which are phenolic-based and exhibit hydrophobic properties. Southern yellow pine was impregnated with a pyrolysis oil-based penetrant using both a high pressure and vacuum impregnation systems, with no significant differences in retention levels. Penetrant concentrations ranging from 5-50% pyrolysis...

Self-organization of critical behavior in controlled general queueing models

NASA Astrophysics Data System (ADS)

Blanchard, Ph.; Hongler, M.-O.

2004-03-01

We consider general queueing models of the (G/G/1) type with service times controlled by the busy period. For feedback control mechanisms driving the system to very high traffic load, it is shown the busy period probability density exhibits a generic - {3}/{2} power law which is a typical mean field behavior of SOC models.

Exhibits Recognition System for Combining Online Services and Offline Services

NASA Astrophysics Data System (ADS)

Ma, He; Liu, Jianbo; Zhang, Yuan; Wu, Xiaoyu

2017-10-01

In order to achieve a more convenient and accurate digital museum navigation, we have developed a real-time and online-to-offline museum exhibits recognition system using image recognition method based on deep learning. In this paper, the client and server of the system are separated and connected through the HTTP. Firstly, by using the client app in the Android mobile phone, the user can take pictures and upload them to the server. Secondly, the features of the picture are extracted using the deep learning network in the server. With the help of the features, the pictures user uploaded are classified with a well-trained SVM. Finally, the classification results are sent to the client and the detailed exhibition’s introduction corresponding to the classification results are shown in the client app. Experimental results demonstrate that the recognition accuracy is close to 100% and the computing time from the image uploading to the exhibit information show is less than 1S. By means of exhibition image recognition algorithm, our implemented exhibits recognition system can combine online detailed exhibition information to the user in the offline exhibition hall so as to achieve better digital navigation.

Design of flexible polyphenylene proton-conducting membrane for next-generation fuel cells.

PubMed

Miyake, Junpei; Taki, Ryunosuke; Mochizuki, Takashi; Shimizu, Ryo; Akiyama, Ryo; Uchida, Makoto; Miyatake, Kenji

2017-10-01

Proton exchange membrane fuel cells (PEMFCs) are promising devices for clean power generation in automotive, stationary, and portable applications. Perfluorosulfonic acid (PFSA) ionomers (for example, Nafion) have been the benchmark PEMs; however, several problems, including high gas permeability, low thermal stability, high production cost, and environmental incompatibility, limit the widespread dissemination of PEMFCs. It is believed that fluorine-free PEMs can potentially address all of these issues; however, none of these membranes have simultaneously met the criteria for both high performance (for example, proton conductivity) and durability (for example, mechanical and chemical stability). We present a polyphenylene-based PEM (SPP-QP) that fulfills the required properties for fuel cell applications. The newly designed PEM exhibits very high proton conductivity, excellent membrane flexibility, low gas permeability, and extremely high stability, with negligible degradation even under accelerated degradation conditions, which has never been achieved with existing fluorine-free PEMs. The polyphenylene PEM also exhibits reasonably high fuel cell performance, with excellent durability under practical conditions. This new PEM extends the limits of existing fluorine-free proton-conductive materials and will help to realize the next generation of PEMFCs via cost reduction as well as the performance improvement compared to the present PFSA-based PEMFC systems.

Magnesium/Lithium-Ion Hybrid Battery with High Reversibility by Employing NaV3O8·1.69H2O Nanobelts as a Positive Electrode.

PubMed

Rashad, Muhammad; Li, Xianfeng; Zhang, Huamin

2018-06-27

Recently, magnesium-ion batteries (MIBs) have been under remarkable research focus owing to their appealingly high energy density and natural abundance of magnesium. Nevertheless, MIBs exhibit a very limited performance because of sluggish solid-state Mg 2+ ion diffusion and high polarizability, which hinder their progress toward commercialization. Herein, we report a Mg 2+ /Li + hybrid-ion battery (MLIB) with NaV 3 O 8 ·1.69H 2 O (NVO) nanobelts synthesized at room temperature working as the positive electrode. In the hybrid-ion system, Li + intercalates/deintercalates along with a small amount of Mg 2+ adsorption at the NVO cathode, whereas the anode side of the cell is dominated by Mg 2+ deposition/dissolution. As a result, the MLIB exhibits a much higher rate capability (i.e., 446 mA h g -1 at 20 mA g -1 ) than the previously reported MLIBs. MLIB maintains a high specific capacity of 200 mA h g -1 at 80 mA g -1 for 150 cycles, showing excellent stability. Moreover, the effect of different Li-ion concentrations (i.e., 0.5-2.0 M) in the electrolyte and cutoff voltage (ranging from 2 to 2.6 V) on the specific capacities are investigated. The current study highlights a strategy to exploit the Mg 2+ /Li + hybrid electrolyte system with various electrode materials for high-performance MIBs.

Porphyrin-Sensitized Evolution of Hydrogen using Dawson and Keplerate Polyoxometalate Photocatalysts.

PubMed

Panagiotopoulos, Athanassios; Douvas, Antonios M; Argitis, Panagiotis; Coutsolelos, Athanassios G

2016-11-23

Hydrogen evolution using photocatalytic systems based on artificial photosynthesis is a major approach toward solar energy conversion and storage. In the polyoxometalate-based photocatalytic systems proposed in the past, middle/near UV light irradiation and noble-metal catalysts were mainly used. Although recently polyoxometalates were sensitized in visible light, photosensitizers or catalysts based on noble metals, and/or poor activity of polyoxometalates were generally obtained. Here we show the highly efficient [turnover number (TON)=215] hydrogen evolution induced by the zinc(II) mesotetrakis(N-methyl-pyridinium-4-yl)porphyrin (ZnTMPyP 4+ ) sensitization of a series of polyoxometalate catalysts (two Dawson type, P 2 Mo 18 O 62 6- and P 2 W 18 O 62 6- anions, and one Keplerate {Mo 132 } cluster) in a visible-light-driven, noble-metal-free, and fully water-soluble system. We attributed the high efficiency for hydrogen evolution to the multi-electron reduction of polyoxometalates and found that: (a) both Dawson polyoxometalates exhibit higher hydrogen evolution efficiency upon ZnTMPyP 4+ sensitization in relation to the direct photoreduction of those compounds; (b) the P 2 Mo 18 O 62 6- anion is more efficient (TON=65 vs. 38, respectively) for hydrogen evolution than the P 2 W 18 O 62 6- anion; and (c) the high nuclearity Keplerate {Mo 132 } cluster exhibits the highest efficiency (TON=215) for hydrogen evolution compared with the polyoxometalates studied. © 2016 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Prokaryotic regulatory systems biology: Common principles governing the functional architectures of Bacillus subtilis and Escherichia coli unveiled by the natural decomposition approach.

PubMed

Freyre-González, Julio A; Treviño-Quintanilla, Luis G; Valtierra-Gutiérrez, Ilse A; Gutiérrez-Ríos, Rosa María; Alonso-Pavón, José A

2012-10-31

Escherichia coli and Bacillus subtilis are two of the best-studied prokaryotic model organisms. Previous analyses of their transcriptional regulatory networks have shown that they exhibit high plasticity during evolution and suggested that both converge to scale-free-like structures. Nevertheless, beyond this suggestion, no analyses have been carried out to identify the common systems-level components and principles governing these organisms. Here we show that these two phylogenetically distant organisms follow a set of common novel biologically consistent systems principles revealed by the mathematically and biologically founded natural decomposition approach. The discovered common functional architecture is a diamond-shaped, matryoshka-like, three-layer (coordination, processing, and integration) hierarchy exhibiting feedback, which is shaped by four systems-level components: global transcription factors (global TFs), locally autonomous modules, basal machinery and intermodular genes. The first mathematical criterion to identify global TFs, the κ-value, was reassessed on B. subtilis and confirmed its high predictive power by identifying all the previously reported, plus three potential, master regulators and eight sigma factors. The functionally conserved cores of modules, basal cell machinery, and a set of non-orthologous common physiological global responses were identified via both orthologous genes and non-orthologous conserved functions. This study reveals novel common systems principles maintained between two phylogenetically distant organisms and provides a comparison of their lifestyle adaptations. Our results shed new light on the systems-level principles and the fundamental functions required by bacteria to sustain life. Copyright © 2012 Elsevier B.V. All rights reserved.

Construction of titanium dioxide nanorod/graphite microfiber hybrid electrodes for a high performance electrochemical glucose biosensor

NASA Astrophysics Data System (ADS)

Zhang, Jian; Yu, Xin; Guo, Weibo; Qiu, Jichuan; Mou, Xiaoning; Li, Aixue; Liu, Hong

2016-04-01

The demand for a highly sensitive and selective glucose biosensor which can be used for implantable or on-time monitoring is constantly increasing. In this work, TiO2 nanorods were synthesized in situ on the surface of graphite microfibers to yield TiO2 nanorod/graphite microfiber hybrid electrodes. The TiO2 nanorods not only retain the high activity of the immobilized glucose molecule, but also promote the direct electron transfer process on the electrode surface. As a working electrode in an electrochemical glucose biosensor in a flowing system, the microfiber hybrid electrodes exhibit high sensitivity, selectivity and stability. Due to its simplicity, low cost, high stability, and unique morphology, the TiO2 nanorod/graphite microfiber hybrid electrode is expected to be an excellent candidate for an implantable biosensor or for in situ flow monitoring.The demand for a highly sensitive and selective glucose biosensor which can be used for implantable or on-time monitoring is constantly increasing. In this work, TiO2 nanorods were synthesized in situ on the surface of graphite microfibers to yield TiO2 nanorod/graphite microfiber hybrid electrodes. The TiO2 nanorods not only retain the high activity of the immobilized glucose molecule, but also promote the direct electron transfer process on the electrode surface. As a working electrode in an electrochemical glucose biosensor in a flowing system, the microfiber hybrid electrodes exhibit high sensitivity, selectivity and stability. Due to its simplicity, low cost, high stability, and unique morphology, the TiO2 nanorod/graphite microfiber hybrid electrode is expected to be an excellent candidate for an implantable biosensor or for in situ flow monitoring. Electronic supplementary information (ESI) available. See DOI: 10.1039/c6nr01360k

Understanding rapid evolution in predator‐prey interactions using the theory of fast‐slow dynamical systems.

PubMed

Cortez, Michael H; Ellner, Stephen P

2010-11-01

The accumulation of evidence that ecologically important traits often evolve at the same time and rate as ecological dynamics (e.g., changes in species' abundances or spatial distributions) has outpaced theory describing the interplay between ecological and evolutionary processes with comparable timescales. The disparity between experiment and theory is partially due to the high dimensionality of models that include both evolutionary and ecological dynamics. Here we show how the theory of fast-slow dynamical systems can be used to reduce model dimension, and we use that body of theory to study a general predator-prey system exhibiting fast evolution in either the predator or the prey. Our approach yields graphical methods with predictive power about when new and unique dynamics (e.g., completely out-of-phase oscillations and cryptic dynamics) can arise in ecological systems exhibiting fast evolution. In addition, we derive analytical expressions for determining when such behavior arises and how evolution affects qualitative properties of the ecological dynamics. Finally, while the theory requires a separation of timescales between the ecological and evolutionary processes, our approach yields insight into systems where the rates of those processes are comparable and thus is a step toward creating a general ecoevolutionary theory.

Experimental investigation of low aspect ratio, large amplitude, aeroelastic energy harvesting systems

NASA Astrophysics Data System (ADS)

Kirschmeier, Benjamin; Summerour, Jacob; Bryant, Matthew

2017-04-01

Interest in clean, stable, and renewable energy harvesting devices has increased dramatically with the volatility of petroleum markets. Specifically, research in aero/hydro kinetic devices has created numerous new horizontal and vertical axis wind turbines, and oscillating wing turbines. Oscillating wing turbines (OWTs) differ from their wind turbine cousins by having a rectangular swept area compared to a circular swept area. The OWT systems also possess a lower tip speed that reduces the overall noise produced by the system. OWTs have undergone significant computational analysis to uncover the underlying flow physics that can drive the system to high efficiencies for single wing oscillations. When two of these devices are placed in tandem configuration, i.e. one placed downstream of the other, they either can constructively or destructively interact. When constructive interactions occurred, they enhance the system efficiency to greater than that of two devices on their own. A new experimental design investigates the dependency of interaction modes on the pitch stiffness of the downstream wing. The experimental results demonstrated that interaction modes are functions of convective time scale and downstream wing pitch stiffness. Heterogeneous combinations of pitch stiffness exhibited constructive and destructive lock-in phenomena whereas the homogeneous combination exhibited only destructive interactions.

[Effect of preparation methods on the metal-porcelain bond strength of Co-Cr alloys].

PubMed

Liu, Jie; Chi, Shuai; Xu, Jin; Wang, Yanyan; Zhan, Desong

2014-04-01

To compare the shear bond strength(SBS) of cast Co-Cr alloys and selective laser melting(SLM) Co-Cr alloys with those of dental porcelain. A dental porcelain (Vita) was applied on cast and SLM Co-Cr alloy specimens (n = 10). SBS test was conducted, and fracture mode analysis was determined. Student's t-test by SPSS 13.0 software was employed to analyze the data. The SLM Co-Cr alloy specimens had lower SBS values than the cast Co-Cr alloy specimens (P > 0.05). The metal-porcelain bond strength value of the cast group was (33.11 +/- 4.98) MPa, and that of the SLM group was (30.94 +/- 5.98) MPa. The specimens in both test groups exhibited mixed failure. The metal-porcelain system processed by SLM exhibit a bond strength that is similar to that of the cast group. This system also display a high precision.

Nano-jewels in biology. Gold and platinum on diamond nanoparticles as antioxidant systems against cellular oxidative stress.

PubMed

Martín, Roberto; Menchón, Cristina; Apostolova, Nadezda; Victor, Victor M; Alvaro, Mercedes; Herance, José Raúl; García, Hermenegildo

2010-11-23

Diamond nanoparticles (DNPs) obtained by explosive detonation have become commercially available. These commercial DNPs can be treated under Fenton conditions (FeSO(4) and H(2)O(2) at acidic pH) to obtain purer DNP samples with a small average particle size (4 nm) and a large population of surface OH groups (HO-DNPs). These Fenton-treated HO-DNPs have been used as a support of gold and platinum nanoparticles (≤2 nm average size). The resulting materials (Au/HO-DNP and Pt/HO-DNP) exhibit a high antioxidant activity against reactive oxygen species induced in a hepatoma cell line. In addition to presenting good biocompatibility, Au/HO- and Pt/HO-DNP exhibit about a two-fold higher antioxidant activity than glutathione, one of the reference antioxidant systems. The most active material against cellular oxidative stress was Au/HO-DNP.

Inhibition of the calcineurin pathway by two tannins, chebulagic acid and chebulanin, isolated from Harrisonia abyssinica Oliv.

PubMed

Lee, Won Jeong; Moon, Jae Sun; Kim, Sung In; Kim, Young Tae; Nash, Oyekanmi; Bahn, Yong-Sun; Kim, Sung Uk

2014-10-01

In order to discover and develop novel signaling inhibitors from plants, a screening system was established targeting the two-component system of Cryptococcus neoformans by using the wild type and a calcineurin mutant of C. neoformans, based on the counter-regulatory action of high-osmolarity glycerol (Hog1) mitogen-activated protein kinase and the calcineurin pathways in C. neoformans. Among 10,000 plant extracts, that from Harrisonia abyssinica Oliv. exhibited the most potent inhibitory activity against C. neoformans var. grubii H99 with fludioxonil. Bioassay-guided fractionation was used to isolate two bioactive compounds from H. abyssinica, and these compounds were identified as chebulagic acid and chebulanin using spectroscopic methods. These compounds specifically inhibited the calcineurin pathway in C. neoformans. Moreover, they exhibited potent antifungal activities against various human pathogenic fungi with minimum inhibitory concentrations ranging from 0.25 to over 64 µg/ml.

Stepwise photochromism of bisnaphthopyrans exhibiting an excitation intensity-dependent color change.

PubMed

Inagaki, Yuki; Mutoh, Katsuya; Abe, Jiro

2018-06-07

Non-linear photoresponses against excitation light intensity are important for the development of attractive photofunctional materials exhibiting high spatial selective photoswitching that is not affected by weak background light. Biphotochromic systems composed of two fast photochromic units have the potential to show a stepwise two-photon absorption process in which the optical properties can be non-linearly controlled by changing the excitation light conditions. Herein, we designed and synthesized novel bisnaphthopyran derivatives containing fast photoswitchable naphthopyran units. The bisnaphthopyran derivatives show a stepwise two-photon-induced photochromic reaction upon UV light irradiation accompanied by a drastic color change due to a large change in the molecular structure between the one-photon product and the two-photon product. Consequently, the color of the bisnaphthopyran derivatives can be non-linearly controlled by changing the excitation intensity. This characteristic photochromic property of the biphotochromic system provides important insight into advanced photoresponsive materials.

A metal-organic tetrahedron as a redox vehicle to encapsulate organic dyes for photocatalytic proton reduction.

PubMed

Jing, Xu; He, Cheng; Yang, Yang; Duan, Chunying

2015-03-25

The design of artificial systems that mimic highly evolved and finely tuned natural photosynthetic systems is a subject of intensive research. We report herein a new approach to constructing supramolecular systems for the photocatalytic generation of hydrogen from water by encapsulating an organic dye molecule into the pocket of a redox-active metal-organic polyhedron. The assembled neutral Co4L4 tetrahedron consists of four ligands and four cobalt ions that connect together in alternating fashion. The cobalt ions are coordinated by three thiosemicarbazone NS chelators and exhibit a redox potential suitable for electrochemical proton reduction. The close proximity between the redox site and the photosensitizer encapsulated in the pocket enables photoinduced electron transfer from the excited state of the photosensitizer to the cobalt-based catalytic sites via a powerful pseudo-intramolecular pathway. The modified supramolecular system exhibits TON values comparable to the highest values reported for related cobalt/fluorescein systems. Control experiments based on a smaller tetrahedral analogue of the vehicle with a filled pocket and a mononuclear compound resembling the cobalt corner of the tetrahedron suggest an enzymatic dynamics behavior. The new, well-elucidated reaction pathways and the increased molarity of the reaction within the confined space render these supramolecular systems superior to other relevant systems.

Interacting shells in AdS spacetime and chaos

NASA Astrophysics Data System (ADS)

Brito, Richard; Cardoso, Vitor; Rocha, Jorge V.

2016-07-01

We study the simplest two-body problem in asymptotically anti-de Sitter spacetime: two, infinitely thin, concentric spherical shells of matter. We include only gravitational interaction between the two shells, but we show that the dynamics of this system is highly nontrivial. We observe prompt collapse to a black hole, delayed collapse and even perpetual oscillatory motion, depending on the initial location of the shells (or their energy content). The system exhibits critical behavior, and we show strong hints that it is also chaotic.

Development of a High Throughput Assay for Indirectly Measuring Phage Growth Using the OmniLog (trademark) System

DTIC Science & Technology

2012-09-01

and phage Giraffe exhibits a similar morphology (Fig. 1A). Phage BA39 (Fig. 1E) appears to belong to the Myoviridae family (icosahedral head and...see later) but this assignment is tentative. Monitoring the kinetics of bacterial growth using OmniLogTM system upon infection with Giraffe phage...spores with and without infection by Giraffe phage are shown in Figure 2A and B respectively. The growth of 7702 without phage infection followed a

A Terahertz VRT spectrometer employing quantum cascade lasers

NASA Astrophysics Data System (ADS)

Cole, William T. S.; Hlavacek, Nik C.; Lee, Alan W. M.; Kao, Tsung-Yu; Hu, Qing; Reno, John L.; Saykally, Richard J.

2015-10-01

The first application of a commercial Terahertz quantum cascade laser (QCL) system for high resolution spectroscopy of supersonic beams is presented. The QCLs exhibited continuous linear voltage tuning over a 2 GHz range about a center frequency of 3.762 THz with ∼1 ppm resolution. A sensitivity of ∼1 ppm fractional absorption was measured with a single pass optical system. Multipass operation at the quantum noise limit of the stressed photoconductor detector would produce a 100-fold improvement.

Room temperature infrared imaging sensors based on highly purified semiconducting carbon nanotubes.

PubMed

Liu, Yang; Wei, Nan; Zhao, Qingliang; Zhang, Dehui; Wang, Sheng; Peng, Lian-Mao

2015-04-21

High performance infrared (IR) imaging systems usually require expensive cooling systems, which are highly undesirable. Here we report the fabrication and performance characteristics of room temperature carbon nanotube (CNT) IR imaging sensors. The CNT IR imaging sensor is based on aligned semiconducting CNT films with 99% purity, and each pixel or device of the imaging sensor consists of aligned strips of CNT asymmetrically contacted by Sc and Pd. We found that the performance of the device is dependent on the CNT channel length. While short channel devices provide a large photocurrent and a rapid response of about 110 μs, long channel length devices exhibit a low dark current and a high signal-to-noise ratio which are critical for obtaining high detectivity. In total, 36 CNT IR imagers are constructed on a single chip, each consists of 3 × 3 pixel arrays. The demonstrated advantages of constructing a high performance IR system using purified semiconducting CNT aligned films include, among other things, fast response, excellent stability and uniformity, ideal linear photocurrent response, high imaging polarization sensitivity and low power consumption.

Phase-Engineered Type-II Multimetal-Selenide Heterostructures toward Low-Power Consumption, Flexible, Transparent, and Wide-Spectrum Photoresponse Photodetectors.

PubMed

Chen, Yu-Ze; Wang, Sheng-Wen; Su, Teng-Yu; Lee, Shao-Hsin; Chen, Chia-Wei; Yang, Chen-Hua; Wang, Kuangye; Kuo, Hao-Chung; Chueh, Yu-Lun

2018-05-01

Phase-engineered type-II metal-selenide heterostructures are demonstrated by directly selenizing indium-tin oxide to form multimetal selenides in a single step. The utilization of a plasma system to assist the selenization facilitates a low-temperature process, which results in large-area films with high uniformity. Compared to single-metal-selenide-based photodetectors, the multimetal-selenide photodetectors exhibit obviously improved performance, which can be attributed to the Schottky contact at the interface for tuning the carrier transport, as well as the type-II heterostructure that is beneficial for the separation of the electron-hole pairs. The multimetal-selenide photodetectors exhibit a response to light over a broad spectrum from UV to visible light with a high responsivity of 0.8 A W -1 and an on/off current ratio of up to 10 2 . Interestingly, all-transparent photodetectors are successfully produced in this work. Moreover, the possibility of fabricating devices on flexible substrates is also demonstrated with sustainable performance, high strain tolerance, and high durability during bending tests. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Thermoplastic deformation of ferromagnetic CoFe-based bulk metallic glasses

NASA Astrophysics Data System (ADS)

Wu, Chenguang; Hu, Renchao; Man, Qikui; Chang, Chuntao; Wang, Xinmin

2017-12-01

The superplastic deformation behavior of the ferromagnetic Co31Fe31Nb8B30 bulk metallic glass (BMG) in the supercooled liquid region was investigated. At a given temperature, the BMG exhibits a Newtonian behavior at low strain rates but a non-Newtonian behavior at high strain rates. The high thermal stability of this glassy alloy system offers an enough processing window to thermoplastic forming (TPF), and the strong processing ability was examined by simple micro-replication experiments. It is demonstrated that the TPF formability on length scales ranging down to nanometers can be achieved in the selected experimental condition. Based on the analysis of deformation behavior, the nearly full density sample (i.e. nearly 100%), was produced from water-atomized glassy powders and consolidated by the hot-pressing technique. The sample exhibits good soft-magnetic and mechanical properties, i.e., low coercive force of 0.43 Oe, high initial permeability of 4100 and high Vickers hardness 1398. These results suggest that the hot-pressing process opens up possibilities for the commercial exploitation of BMGs in engineering applications.

The effect of the size of the system, aspect ratio and impurities concentration on the dynamic of emergent magnetic monopoles in artificial spin ice systems

NASA Astrophysics Data System (ADS)

León, Alejandro

2013-08-01

In this work we study the dynamical properties of a finite array of nanomagnets in artificial kagome spin ice at room temperature. The dynamic response of the array of nanomagnets is studied by implementing a "frustrated celular autómata" (FCA), based in the charge model and dipolar model. The FCA simulations allow us to study in real-time and deterministic way, the dynamic of the system, with minimal computational resource. The update function is defined according to the coordination number of vertices in the system. Our results show that for a set geometric parameters of the array of nanomagnets, the system exhibits high density of Dirac strings and high density emergent magnetic monopoles. A study of the effect of disorder in the arrangement of nanomagnets is incorporated in this work.

Evolutionary fuzzy modeling human diagnostic decisions.

PubMed

Peña-Reyes, Carlos Andrés

2004-05-01

Fuzzy CoCo is a methodology, combining fuzzy logic and evolutionary computation, for constructing systems able to accurately predict the outcome of a human decision-making process, while providing an understandable explanation of the underlying reasoning. Fuzzy logic provides a formal framework for constructing systems exhibiting both good numeric performance (accuracy) and linguistic representation (interpretability). However, fuzzy modeling--meaning the construction of fuzzy systems--is an arduous task, demanding the identification of many parameters. To solve it, we use evolutionary computation techniques (specifically cooperative coevolution), which are widely used to search for adequate solutions in complex spaces. We have successfully applied the algorithm to model the decision processes involved in two breast cancer diagnostic problems, the WBCD problem and the Catalonia mammography interpretation problem, obtaining systems both of high performance and high interpretability. For the Catalonia problem, an evolved system was embedded within a Web-based tool-called COBRA-for aiding radiologists in mammography interpretation.

Poloxamer surface modified trimethyl chitosan nanoparticles for the effective delivery of methotrexate in osteosarcoma.

PubMed

Li, Shenglong; Xiong, Yuyuan; Zhang, Xiaojing

2017-06-01

The present work is an effort to explore the poloxamer-modified trimethyl chitosan (TMC) encapsulated MTX for osteosarcoma treatment in order to improve the therapeutic efficacy and minimize severe toxicity associated with the clinical usage of MTX. The methotrexate-loaded pluronic-chitosan nanoparticles (MTCN) was nanosized and exhibited a controlled release of drug from the carrier system. The MTCN showed higher accumulation in cell cytoplasm region evident by the high red fluorescence indicating its uptake through energy-dependent endocytosis process. MTCN exhibited the increased cytotoxicity in MG63 cells compared free MTX due to its enhanced cellular uptake. Especially, MTCN exhibited a superior apoptosis effect with bright chromatin condensation and nuclear fragmentation was observed and showed remarkably higher apoptosis (∼48%) compared to that of free drug. The results of this investigation clearly demonstrate that the poloxamer-modified trimethyl chitosan (TMC) seems to have a great potential as a drug carrier in cancer chemotherapy. The present research work offers immense scope for further exploitation of poloxamer-modified trimethyl chitosan (TMC) in future for the development of nanoparticulate drug delivery system for cancer chemotherapy. Copyright © 2017. Published by Elsevier Masson SAS.

Modelling and prediction for chaotic fir laser attractor using rational function neural network.

PubMed

Cho, S

2001-02-01

Many real-world systems such as irregular ECG signal, volatility of currency exchange rate and heated fluid reaction exhibit highly complex nonlinear characteristic known as chaos. These chaotic systems cannot be retreated satisfactorily using linear system theory due to its high dimensionality and irregularity. This research focuses on prediction and modelling of chaotic FIR (Far InfraRed) laser system for which the underlying equations are not given. This paper proposed a method for prediction and modelling a chaotic FIR laser time series using rational function neural network. Three network architectures, TDNN (Time Delayed Neural Network), RBF (radial basis function) network and the RF (rational function) network, are also presented. Comparisons between these networks performance show the improvements introduced by the RF network in terms of a decrement in network complexity and better ability of predictability.

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

Rubin, M. B.; Vorobiev, O.; Vitali, E.

Here, a large deformation thermomechanical model is developed for shock loading of a material that can exhibit elastic and inelastic anisotropy. Use is made of evolution equations for a triad of microstructural vectors m i(i=1,2,3) which model elastic deformations and directions of anisotropy. Specific constitutive equations are presented for a material with orthotropic elastic response. The rate of inelasticity depends on an orthotropic yield function that can be used to model weak fault planes with failure in shear and which exhibits a smooth transition to isotropic response at high compression. Moreover, a robust, strongly objective numerical algorithm is proposed formore » both rate-independent and rate-dependent response. The predictions of the continuum model are examined by comparison with exact steady-state solutions. Also, the constitutive equations are used to obtain a simplified continuum model of jointed rock which is compared with high fidelity numerical solutions that model a persistent system of joints explicitly in the rock medium.« less

High pressure mechanical seal

NASA Technical Reports Server (NTRS)

Babel, Henry W. (Inventor); Fuson, Phillip L. (Inventor); Chickles, Colin D. (Inventor); Jones, Cherie A. (Inventor); Anderson, Raymond H. (Inventor)

1995-01-01

A relatively impervious mechanical seal is formed between the outer surface of a tube and the inside surface of a mechanical fitting of a high pressure fluid or hydraulic system by applying a very thin soft metal layer onto the outer surface of the hard metal tube and/or inner surface of the hard metal fitting, prior to swaging the fitting onto the tube. The thickness of such thin metal layer is independent of the size of the tube and/or fittings. Many metals and alloys of those metals exhibit the requisite softness, including silver, gold, nickel, tin, platinum, indium, rhodium and cadmium. Suitably, the coating is about 0.0025 millimeters (0.10 mils) in thickness. After swaging, the tube and fitting combination exhibits very low leak rates on the order or 10.sup.-8 cubic centimeters per second or less as meaured using the Helium leak test.

M-OTDR sensing system based on 3D encoded microstructures

PubMed Central

Sun, Qizhen; Ai, Fan; Liu, Deming; Cheng, Jianwei; Luo, Hongbo; Peng, Kuan; Luo, Yiyang; Yan, Zhijun; Shum, Perry Ping

2017-01-01

In this work, a quasi-distributed sensing scheme named as microstructured OTDR (M-OTDR) by introducing ultra-weak microstructures along the fiber is proposed. Owing to its relative higher reflectivity compared with the backscattered coefficient in fiber and three dimensional (3D) i.e. wavelength/frequency/time encoded property, the M-OTDR system exhibits the superiorities of high signal to noise ratio (SNR), high spatial resolution of millimeter level and high multiplexing capacity up to several ten thousands theoretically. A proof-of-concept system consisting of 64 sensing units is constructed to demonstrate the feasibility and sensing performance. With the help of the demodulation method based on 3D analysis and spectrum reconstruction of the signal light, quasi-distributed temperature sensing with a spatial resolution of 20 cm as well as a measurement resolution of 0.1 °C is realized. PMID:28106132

Optical interconnect technologies for high-bandwidth ICT systems

NASA Astrophysics Data System (ADS)

Chujo, Norio; Takai, Toshiaki; Mizushima, Akiko; Arimoto, Hideo; Matsuoka, Yasunobu; Yamashita, Hiroki; Matsushima, Naoki

2016-03-01

The bandwidth of information and communication technology (ICT) systems is increasing and is predicted to reach more than 10 Tb/s. However, an electrical interconnect cannot achieve such bandwidth because of its density limits. To solve this problem, we propose two types of high-density optical fiber wiring for backplanes and circuit boards such as interface boards and switch boards. One type uses routed ribbon fiber in a circuit board because it has the ability to be formed into complex shapes to avoid interfering with the LSI and electrical components on the board. The backplane is required to exhibit high density and flexibility, so the second type uses loose fiber. We developed a 9.6-Tb/s optical interconnect demonstration system using embedded optical modules, optical backplane, and optical connector in a network apparatus chassis. We achieved 25-Gb/s transmission between FPGAs via the optical backplane.

A 25-kW Series-Resonant Power Converter

NASA Technical Reports Server (NTRS)

Frye, R. J.; Robson, R. R.

1986-01-01

Prototype exhibited efficiency of 93.9 percent. 25-kW resonant dc/dc power converter designed, developed, fabricated, and tested, using Westinghouse D7ST transistors as high-power switches. D7ST transistor characterized for use as switch in series-resonant converters, and refined base-drive circuit developed. Technical base includes advanced switching magnetic, and filter components, mathematical circuit models, control philosophies, and switch-drive strategies. Power-system benefits such as lower losses when used for high-voltage distribution, and reduced magnetics and filter mass realized.

Sexual conflict predicts morphology and behavior in two species of penduline tits

PubMed Central

2010-01-01

Background The evolutionary interests of males and females rarely coincide (sexual conflict), and these conflicting interests influence morphology, behavior and speciation in various organisms. We examined consequences of variation in sexual conflict in two closely-related passerine birds with contrasting breeding systems: the Eurasian penduline tit Remiz pendulinus (EPT) exhibiting a highly polygamous breeding system with sexually antagonistic interests over parental care, and the socially monogamous Cape penduline tit Anthoscopus minutus (CPT). We derived four a priori predictions from sexual conflict theory and tested these using data collected in Central Europe (EPT) and South Africa (CPT). Firstly, we predicted that EPTs exhibit more sexually dimorphic plumage than CPTs due to more intense sexual selection. Secondly, we expected brighter EPT males to provide less care than duller males. Thirdly, since song is a sexually selected trait in many birds, male EPTs were expected to exhibit more complex songs than CPT males. Finally, intense sexual conflict in EPT was expected to lead to low nest attendance as an indication of sexually antagonistic interests, whereas we expected more cooperation between parents in CPT consistent with their socially monogamous breeding system. Results Consistent with our predictions EPTs exhibited greater sexual dimorphism in plumage and more complex song than CPTs, and brighter EPT males provided less care than duller ones. EPT parents attended the nest less frequently and less simultaneously than CPT parents. Conclusions These results are consistent with sexual conflict theory: species in which sexual conflict is more manifested (EPT) exhibited a stronger sexual dimorphism and more elaborated sexually selected traits than species with less intense sexual conflict (CPT). Our results are also consistent with the notion that EPTs attempt to force their partner to work harder as expected under sexual conflict: each member of the breeding pair attempts to shift the costs of care to the other parent. More brightly colored males benefit more from desertion than dull ones, because they are more likely to remate with a new female. Taken together, the comparison between two closely related species with contrasting breeding systems suggest that sexual conflict over care has influenced the evolution of behavior and morphology in penduline tits. PMID:20416066

Sexual conflict predicts morphology and behavior in two species of penduline tits.

PubMed

van Dijk, René E; Pogány, Akos; Komdeur, Jan; Lloyd, Penn; Székely, Tamás

2010-04-23

The evolutionary interests of males and females rarely coincide (sexual conflict), and these conflicting interests influence morphology, behavior and speciation in various organisms. We examined consequences of variation in sexual conflict in two closely-related passerine birds with contrasting breeding systems: the Eurasian penduline tit Remiz pendulinus (EPT) exhibiting a highly polygamous breeding system with sexually antagonistic interests over parental care, and the socially monogamous Cape penduline tit Anthoscopus minutus (CPT). We derived four a priori predictions from sexual conflict theory and tested these using data collected in Central Europe (EPT) and South Africa (CPT). Firstly, we predicted that EPTs exhibit more sexually dimorphic plumage than CPTs due to more intense sexual selection. Secondly, we expected brighter EPT males to provide less care than duller males. Thirdly, since song is a sexually selected trait in many birds, male EPTs were expected to exhibit more complex songs than CPT males. Finally, intense sexual conflict in EPT was expected to lead to low nest attendance as an indication of sexually antagonistic interests, whereas we expected more cooperation between parents in CPT consistent with their socially monogamous breeding system. Consistent with our predictions EPTs exhibited greater sexual dimorphism in plumage and more complex song than CPTs, and brighter EPT males provided less care than duller ones. EPT parents attended the nest less frequently and less simultaneously than CPT parents. These results are consistent with sexual conflict theory: species in which sexual conflict is more manifested (EPT) exhibited a stronger sexual dimorphism and more elaborated sexually selected traits than species with less intense sexual conflict (CPT). Our results are also consistent with the notion that EPTs attempt to force their partner to work harder as expected under sexual conflict: each member of the breeding pair attempts to shift the costs of care to the other parent. More brightly colored males benefit more from desertion than dull ones, because they are more likely to remate with a new female. Taken together, the comparison between two closely related species with contrasting breeding systems suggest that sexual conflict over care has influenced the evolution of behavior and morphology in penduline tits.

Characterization of Antimicrobial Agent Loaded Eudragit RS Solvent Exchange-Induced In Situ Forming Gels for Periodontitis Treatment.

PubMed

Phaechamud, Thawatchai; Jantadee, Takron; Mahadlek, Jongjan; Charoensuksai, Purin; Pichayakorn, Wiwat

2017-02-01

Eudragit RS (ERS), a quaternary polyacrylate positively charged polymer, exhibits a very low permeability and swells in aqueous media independently of pH without dissolving. Owing to its high solubility in N-methyl pyrrolidone (NMP), it was interesting to apply as polymer matrix for solvent-exchanged in situ forming gel. The aim of this research was to prepare in situ forming gels from ERS to deliver the antimicrobial agents (doxycycline hyclate, metronidazole, and benzoyl peroxide) for periodontitis treatment. They were evaluated for viscosity and rheology, gel formation, syringeability, drug release, and antimicrobial activities. The solvent exchange between NMP and an external aqueous simulated gingival crevicular fluid stimulated the dissolved ERS transforming into the opaque rigid gel. Antimicrobial agent loaded ERS systems exhibited Newtonian flow with acceptable syringeability. The higher-loaded ERS promoted the more prolongation of drug release because of the retardation of water diffusion into the precipitated matrix. Antimicrobial activities against Staphylococcus aureus, Escherichia coli, Candida albicans, Streptococcus mutans, and Porphyromonas gingivalis depended on type of drugs and test microorganisms. Doxycycline hyclate loaded ERS systems showed these activities greater than the others; however, all of them could inhibit all test microorganisms. Thus, the solvent exchange-induced in situ forming gels comprising ERS-antimicrobial drugs exhibited potential use as localized delivery systems for periodontitis treatment.

High-frequency vibration energy harvesting from impulsive excitation utilizing intentional dynamic instability caused by strong nonlinearity

NASA Astrophysics Data System (ADS)

Remick, Kevin; Dane Quinn, D.; Michael McFarland, D.; Bergman, Lawrence; Vakakis, Alexander

2016-05-01

The authors investigate a vibration-based energy harvesting system utilizing essential (nonlinearizable) nonlinearities and electromagnetic coupling elements. The system consists of a grounded, weakly damped linear oscillator (primary system) subjected to a single impulsive load. This primary system is coupled to a lightweight, damped oscillating attachment (denoted as nonlinear energy sink, NES) via a neodymium magnet and an inductance coil, and a piano wire, which generates an essential geometric cubic stiffness nonlinearity. Under impulsive input, the transient damped dynamics of this system exhibit transient resonance captures (TRCs) causing intentional large-amplitude and high-frequency instabilities in the response of the NES. These TRCs result in strong energy transfer from the directly excited primary system to the light-weight attachment. The energy is harvested by the electromagnetic elements in the coupling and, in the present case, dissipated in a resistive element in the electrical circuit. The primary goal of this work is to numerically, analytically, and experimentally demonstrate the efficacy of employing this type of intentional high-frequency dynamic instability to achieve enhanced vibration energy harvesting under impulsive excitation.

A temperature-tolerant multiplex elements and genes screening system for genetically modified organisms based on dual priming oligonucleotide primers and capillary electrophoresis.

PubMed

Fu, Wei; Wei, Shuang; Wang, Chenguang; Du, Zhixin; Zhu, Pengyu; Wu, Xiyang; Wu, Gang; Zhu, Shuifang

2017-08-15

High throughput screening systems are the preferred solution to meet the urgent requirement of increasing number of genetically modified organisms (GMOs). In this study, we have successfully developed a multiplex GMO element screening system with dual priming oligonucleotide (DPO) primers. This system can detect the cauliflower mosaic virus 35S (CaMV 35S), terminator of nopaline synthase gene (NOS), figwort mosaic virus 35S (FMV 35S) promoter, neomycin phosphotransferaseII (NPTII), Bt Cry 1Ab, phosphinothricin acetyltransferase genes (bar) and Streptomyces viridochromogenes (pat) simultaneously, which covers more than 90% of all authorized GMO species worldwide. This system exhibits a high tolerance to annealing temperatures, high specificity and a limit of detection equal to conventional PCR. A total of 214 samples from markets, national entry-exit agencies, the Institute for Reference Materials and Measurement (IRMM) and the American Oil Chemists' Society (AOCS) were also tested for applicability. This screening system is therefore suitable for GMO screening. Copyright © 2017 Elsevier Ltd. All rights reserved.

A new high-speed IR camera system

NASA Technical Reports Server (NTRS)

Travis, Jeffrey W.; Shu, Peter K.; Jhabvala, Murzy D.; Kasten, Michael S.; Moseley, Samuel H.; Casey, Sean C.; Mcgovern, Lawrence K.; Luers, Philip J.; Dabney, Philip W.; Kaipa, Ravi C.

1994-01-01

A multi-organizational team at the Goddard Space Flight Center is developing a new far infrared (FIR) camera system which furthers the state of the art for this type of instrument by the incorporating recent advances in several technological disciplines. All aspects of the camera system are optimized for operation at the high data rates required for astronomical observations in the far infrared. The instrument is built around a Blocked Impurity Band (BIB) detector array which exhibits responsivity over a broad wavelength band and which is capable of operating at 1000 frames/sec, and consists of a focal plane dewar, a compact camera head electronics package, and a Digital Signal Processor (DSP)-based data system residing in a standard 486 personal computer. In this paper we discuss the overall system architecture, the focal plane dewar, and advanced features and design considerations for the electronics. This system, or one derived from it, may prove useful for many commercial and/or industrial infrared imaging or spectroscopic applications, including thermal machine vision for robotic manufacturing, photographic observation of short-duration thermal events such as combustion or chemical reactions, and high-resolution surveillance imaging.

Dynamic video encryption algorithm for H.264/AVC based on a spatiotemporal chaos system.

PubMed

Xu, Hui; Tong, Xiao-Jun; Zhang, Miao; Wang, Zhu; Li, Ling-Hao

2016-06-01

Video encryption schemes mostly employ the selective encryption method to encrypt parts of important and sensitive video information, aiming to ensure the real-time performance and encryption efficiency. The classic block cipher is not applicable to video encryption due to the high computational overhead. In this paper, we propose the encryption selection control module to encrypt video syntax elements dynamically which is controlled by the chaotic pseudorandom sequence. A novel spatiotemporal chaos system and binarization method is used to generate a key stream for encrypting the chosen syntax elements. The proposed scheme enhances the resistance against attacks through the dynamic encryption process and high-security stream cipher. Experimental results show that the proposed method exhibits high security and high efficiency with little effect on the compression ratio and time cost.

A bifunctional luminescent Tb(III)-metal-organic framework by a tetracarboxylate ligand for highly selective detection of Fe3+ cation and Cr2O72- anion

NASA Astrophysics Data System (ADS)

Yu, Li; Wang, Chao; Hu, Chang-Jiang; Dong, Wen-Wen; Wu, Ya-Pan; Li, Dong-Sheng; Zhao, Jun

2018-06-01

Reaction of Tb3+ ions with p-terphenyl-3,3″,5,5″-tetracarboxylic acid (H4ptptc) in a mixed solvent system has afforded a new metal-organic framework formulated as [Tb2(ptptc)1.5(H2O)2]n (1). Compound 1 displays a 3D (5,6,8)-connected framework with fascinating one-dimensional triangle open channels. The luminescence explorations demonstrated that 1 exhibits highly selective and sensitive response to Fe3+ in DMF solution and biological system through luminescence quenching effects. In addition, 1 also shows high detection for the Cr2O72-, making it a promising dual functional materials for detecting Fe3+ cation and Cr2O72- anion with high sensitivity and selectivity.

Evaluation of the pathotec Rapid I-D system for identification of Enterobacteriaceae.

PubMed Central

Smith, P B; Rhoden, D L; Tomfohrde, K M

1975-01-01

The PathoTec Rapid I-D System for identifying Enterobacteriaceae was evaluated with 471 cultures. In 4,910 individual test comparisons, 95.5% of the results agreed, with results of only two test strips, those for esculin hydrolysis and urease production, agreeing with conventional tests in less than 94% of the trials. The PathoTec system exhibited 94.3% accuracy in identifying these cultures in a double-blind study with conventional media and procedures as the alternate system. Two newly developed test strips, for 0-nitrophenyl-beta-D-galactopyranoside and ornithine decarboxylase, were found to be highly reliable. PMID:1041590

Detecting unstable periodic orbits in chaotic time series using synchronization

NASA Astrophysics Data System (ADS)

Olyaei, Ali Azimi; Wu, Christine; Kinsner, Witold

2017-07-01

An alternative approach of detecting unstable periodic orbits in chaotic time series is proposed using synchronization techniques. A master-slave synchronization scheme is developed, in which the chaotic system drives a system of harmonic oscillators through a proper coupling condition. The proposed scheme is designed so that the power of the coupling signal exhibits notches that drop to zero once the system approaches an unstable orbit yielding an explicit indication of the presence of a periodic motion. The results shows that the proposed approach is particularly suitable in practical situations, where the time series is short and noisy, or it is obtained from high-dimensional chaotic systems.

Paleovalley fills: Trunk vs. tributary

USGS Publications Warehouse

Kvale, E.P.; Archer, A.W.

2007-01-01

A late Mississippian-early Pennsylvanian eustatic sea level drop resulted in a complex lowstand drainage network being eroded across the Illinois Basin in the eastern United States. This drainage system was filled during the early part of the Pennsylvanian. Distinct differences can be recognized between the trunk and tributary paleovalley fills. Fills preserved within the trunk systems tend to be fluvially dominated and consist of bed-load deposits of coarse- to medium-grained sandstone and conglomerate. Conversely, the incised valleys of tributary systems tend to be filled with dark mudstone, thinly interbedded sandstones, and mudstones and siltstones. These finer grained facies exhibit marine influences manifested by tidal rhythmites, certain traces fossils, and macro- and microfauna. Examples of tributary and trunk systems, separated by no more than 7 km (4.3 mi) along strike, exhibit these styles of highly contrasting fills. Useful analogs for understanding this Pennsylvanian system include the Quaternary glacial sluiceways present in the lower Ohio, White, and Wabash river valleys of Indiana (United States) and the modern Amazon River (Brazil). Both the Amazon River and the Quaternary rivers of Indiana have (or had) trunk rivers that are (were) dominated by large quantities of bed load relative to their tributaries. The trunk valley systems of these analogs aggraded much more rapidly than their tributary valleys, which evolved into lakes because depositional rates along the trunk are (were) so high that the mouths of the tributaries have been dammed by bed-load deposits. These Holocene systems illustrate that sediment yields can significantly influence the nature of fill successions within incised valleys independent of rates of sea level changes or proximity to highstand coastlines. Copyright ?? 2007. The American Association of Petroleum Geologists. All rights reserved.

Formal development of a clock synchronization circuit

NASA Technical Reports Server (NTRS)

Miner, Paul S.

1995-01-01

This talk presents the latest stage in formal development of a fault-tolerant clock synchronization circuit. The development spans from a high level specification of the required properties to a circuit realizing the core function of the system. An abstract description of an algorithm has been verified to satisfy the high-level properties using the mechanical verification system EHDM. This abstract description is recast as a behavioral specification input to the Digital Design Derivation system (DDD) developed at Indiana University. DDD provides a formal design algebra for developing correct digital hardware. Using DDD as the principle design environment, a core circuit implementing the clock synchronization algorithm was developed. The design process consisted of standard DDD transformations augmented with an ad hoc refinement justified using the Prototype Verification System (PVS) from SRI International. Subsequent to the above development, Wilfredo Torres-Pomales discovered an area-efficient realization of the same function. Establishing correctness of this optimization requires reasoning in arithmetic, so a general verification is outside the domain of both DDD transformations and model-checking techniques. DDD represents digital hardware by systems of mutually recursive stream equations. A collection of PVS theories was developed to aid in reasoning about DDD-style streams. These theories include a combinator for defining streams that satisfy stream equations, and a means for proving stream equivalence by exhibiting a stream bisimulation. DDD was used to isolate the sub-system involved in Torres-Pomales' optimization. The equivalence between the original design and the optimized verified was verified in PVS by exhibiting a suitable bisimulation. The verification depended upon type constraints on the input streams and made extensive use of the PVS type system. The dependent types in PVS provided a useful mechanism for defining an appropriate bisimulation.

Connecting the Public to Natural Hazards Through a Hands-on Museum Exhibit

NASA Astrophysics Data System (ADS)

Olds, S. E.; Rowe, S. M.; Hanshumaker, W.; Farley, M.

2014-12-01

Communities along the coast of Oregon, Washington, and northern California live with the threat of potentially devastating subduction zone earthquakes and subsequent tsunami that could happen at any time. Both residents and visitors to the coast need to be aware of the potential impacts such hazards can have on their lives as well as what to do during an earthquake and before a tsunami hits. To raise awareness of both natural hazards and the technologies used to monitor them, UNAVCO designed and installed a museum exhibit on display at Oregon State University's Hatfield Marine Science Center (HMSC) Visitor Center in Newport, Oregon. The objectives for the exhibit are to increase familiarization with the natural hazards of earthquakes and tsunamis in the Cascadia region, to explain the connection between the crust's movement and compression over time with the potential strength of a subduction-zone earthquake, and to inform visitors about high-precision, high-rate GPS technology. The exhibit includes multiple hands-on models and an authentic GPS monitoring station. Additionally, panels explain the science behind the models, potential impacts of a great earthquake to society, and actions visitors can take to practice earthquake safety through the Great ShakeOut earthquake drill. Over the past year that the exhibit has been open to the public, it has been visited by over 100,000 people including students, family and senior groups, and the general public. Anecdotal evidence indicates that two components of the exhibit create the most visitor impact providing visitors with 'ah ha moments': a real-scale tape measure showing the approximate 12 foot distance the coast has compressed over the past 300+ years, and a flexible map illustrating that the coastal areas are compressing the most compared to areas further inland. Through HMSC's NSF-funded Cyberlab automated visitor data collection system, we have been able to document and analyze a variety of visitor characteristics including number of people visiting the various elements of the exhibit, time on exhibit elements, order of visitation, grouping characteristics, and basic use of the exhibit as a learning tool by groups. During this session we will share the successes and challenges of the exhibit and next steps to further raise awareness about natural hazards of the region.

Development and Testing of a Shape Memory Alloy-Driven Composite Morphing Radiator

NASA Astrophysics Data System (ADS)

Walgren, P.; Bertagne, C.; Wescott, M.; Benafan, O.; Erickson, L.; Whitcomb, J.; Hartl, D.

2018-03-01

Future crewed deep space missions will require thermal control systems that can accommodate larger fluctuations in temperature and heat rejection loads than current designs. To maintain the crew cabin at habitable temperatures throughout the entire mission profile, radiators will be required to exhibit turndown ratios (defined as the ratio between the maximum and minimum heat rejection rates) as high as 12:1. Potential solutions to increase radiator turndown ratios include designs that vary the heat rejection rate by changing shape, hence changing the rate of radiation to space. Shape memory alloys exhibit thermally driven phase transformations and thus can be used for both the control and actuation of such a morphing radiator with a single active structural component that transduces thermal energy into motion. This work focuses on designing a high-performance composite radiator panel and investigating the behavior of various SMA actuators in this application. Three designs were fabricated and subsequently tested in a relevant thermal vacuum environment; all three exhibited repeatable morphing behavior, and it is shown through validated computational analysis that the morphing radiator concept can achieve a turndown ratio of 27:1 with a number of simple configuration changes.

Smart Photosensitizer: Tumor-Triggered Oncotherapy by Self-Assembly Photodynamic Nanodots.

PubMed

Jia, Yuhua; Li, Jinyu; Chen, Jincan; Hu, Ping; Jiang, Longguang; Chen, Xueyuan; Huang, Mingdong; Chen, Zhuo; Xu, Peng

2018-05-09

Clinical photosensitizers suffer from the disadvantages of fast photobleaching and high systemic toxicities because of the off-target photodynamic effects. To address these problems, we report a self-assembled pentalysine-phthalocyanine assembly nanodots (PPAN) fabricated by an amphipathic photosensitizer-peptide conjugate. We triggered the photodynamic therapy effects of photosensitizers by precisely controlling the assembly and disintegration of the nanodots. In physiological aqueous conditions, PPAN exhibited a size-tunable spherical conformation with a highly positive shell of the polypeptides and a hydrophobic core of the π-stacking Pc moieties. The assembly conformation suppressed the fluorescence and the reactive oxygen species generation of the monomeric photosensitizer molecules (mono-Pc) and thus declined the photobleaching and off-target photodynamic effects. However, tumor cells disintegrated PPAN and released the mono-Pc molecules, which exhibited fluorescence for detection and the photodynamic effects for the elimination of the tumor tissues. The molecular dynamics simulations revealed the various assembly configurations of PPAN and illustrated the assembly mechanism. At the cellular level, PPAN exhibited a remarkable phototoxicity to breast cancer cells with the IC 50 values in a low nanomolar range. By using the subcutaneous and orthotopic breast cancer animal models, we also demonstrated the excellent antitumor efficacies of PPAN in vivo.

Nanocolloids in Natural Water: Isolation, Characterization, and Toxicity.

PubMed

Ouyang, Shaohu; Hu, Xiangang; Zhou, Qixing; Li, Xiaokang; Miao, Xinyu; Zhou, Ruiren

2018-04-17

Nanocolloids are widespread in natural water systems, but their characterization and ecological risks are largely unknown. Herein, tangential flow ultrafiltration (TFU) was used to separate and concentrate nanocolloids from surface waters. Unexpectedly, nanocolloids were present in high concentrations ranging from 3.7 to 7.2 mg/L in the surface waters of the Harihe River in Tianjin City, China. Most of the nanocolloids were 10-40 nm in size, contained various trace metals and polycyclic aromatic hydrocarbons, and exhibited fluorescence properties. Envelopment effects and aggregation of Chlorella vulgaris in the presence of nanocolloids were observed. Nanocolloids entered cells and nanocolloid-exposed cells exhibited stronger plasmolysis, chloroplast damage and more starch grains than the control cells. Moreover, nanocolloids inhibited the cell growth, promoted reactive oxygen species (ROS), reduce the chlorophyll a content and increased the cell permeability. The genotoxicity of nanocolloids was also observed. The metabolomics analysis revealed a significant ( p < 0.05) downregulation of amino acids and upregulation of fatty acids contributing to ROS increase, chlorophyll a decrease and plasmolysis. The present work reveals that nanocolloids, which are different from specific, engineered nanoparticles (e.g., Ag nanoparticles), are present at high concentrations, exhibit an obvious toxicity in environments, and deserve more attention in the future.

Topological crystalline insulator SnTe nanoribbons

NASA Astrophysics Data System (ADS)

Dahal, Bishnu R.; Dulal, Rajendra P.; Pegg, Ian L.; Philip, John

2017-03-01

Topological crystalline insulators are systems in which a band inversion that is protected by crystalline mirror symmetry gives rise to nontrivial topological surface states. SnTe is a topological crystalline insulator. It exhibits p-type conductivity due to Sn vacancies and Te antisites, which leads to high carrier density in the bulk. Thus growth of high quality SnTe is a prerequisite for understanding the topological crystalline insulating behavior. We have grown SnTe nanoribbons using a solution method. The width of the SnTe ribbons varies from 500 nm to 2 μm. They exhibit rock salt crystal structure with a lattice parameter of 6.32 Å. The solution method that we have adapted uses low temperature, so the Sn vacancies can be controlled. The solution grown SnTe nanoribbons exhibit strong semiconducting behavior with an activation energy of 240 meV. This activation energy matches with the calculated band gap for SnTe with a lattice parameter of 6.32 Å, which is higher than that reported for bulk SnTe. The higher activation energy makes the thermal excitation of bulk charges very difficult on the surface. As a result, the topological surfaces will be free from the disturbance caused by the thermal excitations

Peptide π-Electron Conjugates: Organic Electronics for Biology?

PubMed

Ardoña, Herdeline Ann M; Tovar, John D

2015-12-16

Highly ordered arrays of π-conjugated molecules are often viewed as a prerequisite for effective charge-transporting materials. Studies involving these materials have traditionally focused on organic electronic devices, with more recent emphasis on biological systems. In order to facilitate the transition to biological environments, biomolecules that can promote hierarchical ordering and water solubility are often covalently appended to the π-electron unit. This review highlights recent work on π-conjugated systems bound to peptide moieties that exhibit self-assembly and aims to provide an overview on the development and emerging applications of peptide-based supramolecular π-electron systems.

Tunable electro-optic filter stack

DOEpatents

Fontecchio, Adam K.; Shriyan, Sameet K.; Bellingham, Alyssa

2017-09-05

A holographic polymer dispersed liquid crystal (HPDLC) tunable filter exhibits switching times of no more than 20 microseconds. The HPDLC tunable filter can be utilized in a variety of applications. An HPDLC tunable filter stack can be utilized in a hyperspectral imaging system capable of spectrally multiplexing hyperspectral imaging data acquired while the hyperspectral imaging system is airborne. HPDLC tunable filter stacks can be utilized in high speed switchable optical shielding systems, for example as a coating for a visor or an aircraft canopy. These HPDLC tunable filter stacks can be fabricated using a spin coating apparatus and associated fabrication methods.

Massive companions of binary systems

NASA Astrophysics Data System (ADS)

Jableka, D.; Zola, S.; Zakrzewski, B.; Kreiner, J. M.; Ogloza, W.

2018-04-01

We examined the O-C diagrams of eclipsing binary systems and selected these exhibiting cyclic shape, either sinusoidal or quasi sinusoidal. Assuming these variations being due to the Light Time Travel effect (LTE), we estimated the parameters of companions with the Monte Carlo method. As a result, we identified nearly two dozen of eclipsing systems that might have companions with a minimum mass larger than that of a neutron star. Their masses fall into the range between 1.7 and 34 solar masses. This sample of triples with high mass companions can be confirmed with the help of observations gathered by Gaia: parallaxes and astrometric measurements.

Thermalization without eigenstate thermalization hypothesis after a quantum quench.

PubMed

Mori, Takashi; Shiraishi, Naoto

2017-08-01

Nonequilibrium dynamics of a nonintegrable system without the eigenstate thermalization hypothesis is studied. It is shown that, in the thermodynamic limit, this model thermalizes after an arbitrary quantum quench at finite temperature, although it does not satisfy the eigenstate thermalization hypothesis. In contrast, when the system size is finite and the temperature is low enough, the system may not thermalize. In this case, the steady state is well described by the generalized Gibbs ensemble constructed by using highly nonlocal conserved quantities. We also show that this model exhibits prethermalization, in which the prethermalized state is characterized by nonthermal energy eigenstates.

A high-speed pnCCD detector system for optical applications

NASA Astrophysics Data System (ADS)

Hartmann, R.; Buttler, W.; Gorke, H.; Herrmann, S.; Holl, P.; Meidinger, N.; Soltau, H.; Strüder, L.

2006-11-01

Measurements of a frame-store pnCCD detector system, optimized for high-speed applications in the optical and near infrared (NIR) region, will be presented. The device with an image area of 13.5 mm by 13.5 mm and a pixelsize of 51 μm by 51 μm exhibits a readout time faster than 1100 frames per second with an overall electronic noise contribution of less than three electrons. Variable operation modes of the detector system allow for even higher readout speeds by a pixel binning in transfer direction or, at slightly slower readout speeds, a further improvement in noise performance. We will also present the concept of a data acquisition system being able to handle pixel rates of more than 75 megapixel per second. The application of an anti-reflective coating on the ultra-thin entrance window of the back illuminated detector together with the large sensitive volume ensures a high and uniform detection efficiency from the ultra violet to the NIR.

The effect of external magnetic field on the Raman peaks in manganites

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

Sahu, A. K., E-mail: ajitsahu@seemantaengg.ac.in; Rout, G. C.

2014-04-24

We report here a microscopic theoretical model study exhibiting the effect of external magnetic field on the Raman excitation peaks in the CMR manganite system. The Hamiltonian consists of Jahn-Teller (J-T) distortion in e{sub g} band, the double exchange interaction and the Heisenberg spin-spin interaction. Further the phonons are coupled to e{sub g} band electrons, J-T distorted e{sub g} band and the double exchange interaction. The Raman spectral intensity is calculated from the imaginary part of the phonon Green function. The spectra exhibits three peaks besides a very weak high energy peak. The magnetic field effect on these peaks aremore » reported.« less

Society for the advancement of material and process engineering. 41st International SAMPE symposium and exhibition, Volume 41, Books 1 and 2

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

NONE

This document contains reports which were presented at the 41st International Society For The Advancement of Material and Process Engineering Symposium and Exhibition. Topics include: structural integrity of aging aircraft; composite materials development; affordable composites and processes; corrosion characterization of aging aircraft; adhesive advances; composite design; dual use materials and processing; repair of aircraft structures; adhesive inspection; materials systems for infrastructure; fire safety; composite impact/energy absorption; advanced materials for space; seismic retrofit; high temperature resins; preform technology; thermoplastics; alternative energy and transportation; manufacturing; and durability. Individual reports have been processed separately for the United States Department of Energy databases.

49.6 Gb/s direct detection DMT transmission over 40 km single mode fibre using an electrically packaged silicon photonic modulator.

PubMed

Lacava, C; Cardea, I; Demirtzioglou, I; Khoja, A E; Ke, Li; Thomson, D J; Ruan, X; Zhang, F; Reed, G T; Richardson, D J; Petropoulos, P

2017-11-27

We present the characterization of a silicon Mach-Zehnder modulator with electrical packaging and show that it exhibits a large third-order intermodulation spurious-free dynamic range (> 100 dB Hz 2/3 ). This characteristic renders the modulator particularly suitable for the generation of high spectral efficiency discrete multi-tone signals and we experimentally demonstrate a single-channel, direct detection transmission system operating at 49.6 Gb/s, exhibiting a baseband spectral efficiency of 5 b/s/Hz. Successful transmission is demonstrated over various lengths of single mode fibre up to 40 km, without the need of any amplification or dispersion compensation.

Radiation-hardened nano-particles-based Erbium-doped fiber for space environment

NASA Astrophysics Data System (ADS)

Thomas, Jérémie; Myara, Mikhaël.; Signoret, Philippe; Burov, Ekaterina; Pastouret, Alain; Melin, Gilles; Boivin, David; Gilard, Olivier; Sotom, Michel

2017-11-01

We demonstrate for the first time a radiationresistant Erbium-Doped Fiber exhibiting performances that can fill the requirements of Erbium-Doped Fiber Amplifiers for space applications. This is based on an Aluminum co-doping atom reduction enabled by Nanoparticules Doping-Process. For this purpose, we developed several fibers containing very different erbium and aluminum concentrations, and tested them in the same optical amplifier configuration. This work allows to bring to the fore a highly radiation resistant Erbium-doped pure silica optical fiber exhibiting a low quenching level. This result is an important step as the EDFA is increasingly recognized as an enabling technology for the extensive use of photonic sub-systems in future satellites.

Microgravity fluid management requirements of advanced solar dynamic power systems

NASA Technical Reports Server (NTRS)

Migra, Robert P.

1987-01-01

The advanced solar dynamic system (ASDS) program is aimed at developing the technology for highly efficient, lightweight space power systems. The approach is to evaluate Stirling, Brayton and liquid metal Rankine power conversion systems (PCS) over the temperature range of 1025 to 1400K, identify the critical technologies and develop these technologies. Microgravity fluid management technology is required in several areas of this program, namely, thermal energy storage (TES), heat pipe applications and liquid metal, two phase flow Rankine systems. Utilization of the heat of fusion of phase change materials offers potential for smaller, lighter TES systems. The candidate TES materials exhibit large volume change with the phase change. The heat pipe is an energy dense heat transfer device. A high temperature application may transfer heat from the solar receiver to the PCS working fluid and/or TES. A low temperature application may transfer waste heat from the PCS to the radiator. The liquid metal Rankine PCS requires management of the boiling/condensing process typical of two phase flow systems.

Pain Behavior in Rheumatoid Arthritis Patients: Identification of Pain Behavior Subgroups

PubMed Central

Waters, Sandra J.; Riordan, Paul A.; Keefe, Francis J.; Lefebvre, John C.

2008-01-01

This study used Ward’s minimum variance hierarchical cluster analysis to identify homogeneous subgroups of rheumatoid arthritis patients suffering from chronic pain who exhibited similar pain behavior patterns during a videotaped behavior sample. Ninety-two rheumatoid arthritis patients were divided into two samples. Six motor pain behaviors were examined: guarding, bracing, active rubbing, rigidity, grimacing, and sighing. The cluster analysis procedure identified four similar subgroups in Sample 1 and Sample 2. The first subgroup exhibited low levels of all pain behaviors. The second subgroup exhibited a high level of guarding and low levels of other pain behaviors. The third subgroup exhibited high levels of guarding and rigidity and low levels of other pain behaviors. The fourth subgroup exhibited high levels of guarding and active rubbing and low levels of other pain behaviors. Sample 1 contained a fifth subgroup that exhibited a high level of active rubbing and low levels of other pain measures. The results of this study suggest that there are homogeneous subgroups within rheumatoid arthritis patient populations who differ in the motor pain behaviors they exhibit. PMID:18358682

High-Voltage Lithium-Metal Batteries Enabled by Localized High-Concentration Electrolytes.

PubMed

Chen, Shuru; Zheng, Jianming; Mei, Donghai; Han, Kee Sung; Engelhard, Mark H; Zhao, Wengao; Xu, Wu; Liu, Jun; Zhang, Ji-Guang

2018-03-25

Rechargeable lithium-metal batteries (LMBs) are regarded as the "holy grail" of energy-storage systems, but the electrolytes that are highly stable with both a lithium-metal anode and high-voltage cathodes still remain a great challenge. Here a novel "localized high-concentration electrolyte" (HCE; 1.2 m lithium bis(fluorosulfonyl)imide in a mixture of dimethyl carbonate/bis(2,2,2-trifluoroethyl) ether (1:2 by mol)) is reported that enables dendrite-free cycling of lithium-metal anodes with high Coulombic efficiency (99.5%) and excellent capacity retention (>80% after 700 cycles) of Li||LiNi 1/3 Mn 1/3 Co 1/3 O 2 batteries. Unlike the HCEs reported before, the electrolyte reported in this work exhibits low concentration, low cost, low viscosity, improved conductivity, and good wettability that make LMBs closer to practical applications. The fundamental concept of "localized HCEs" developed in this work can also be applied to other battery systems, sensors, supercapacitors, and other electrochemical systems. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Ion-Responsive Drug Delivery Systems.

PubMed

Yoshida, Takayuki; Shakushiro, Kohsuke; Sako, Kazuhiro

2018-02-08

Some kinds of cations and anions are contained in body fluids such as blood, interstitial fluid, gastrointestinal juice, and tears at relatively high concentration. Ionresponsive drug delivery is available to design the unique dosage formulations which provide optimized drug therapy with effective, safe and convenient dosing of drugs. The objective of the present review was to collect, summarize, and categorize recent research findings on ion-responsive drug delivery systems. Ions in body fluid/formulations caused structural changes of polymers/molecules contained in the formulations, allow formulations exhibit functions. The polymers/molecules responding to ions were ion-exchange resins/fibers, anionic or cationic polymers, polymers exhibiting transition at lower critical solution temperature, self-assemble supramolecular systems, peptides, and metalorganic frameworks. The functions of ion-responsive drug delivery systems were categorized to controlled drug release, site-specific drug release, in situ gelation, prolonged retention at the target sites, and enhancement of drug permeation. Administration of the formulations via oral, ophthalmic, transdermal, and nasal routes has showed significant advantages in the recent literatures. Many kinds of drug delivery systems responding to ions have been reported recently for several administration routes. Improvement and advancement of these systems can maximize drugs potential and contribute to patients in the world. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

1997 IEEE/LEOS Summer Topical Meeting on Gallium Nitride Materials, Processing and Devices Held in Montreal, Quebec, Canada on 11-15 August 1997

DTIC Science & Technology

1998-01-01

photochemical exposure, these monomer systems form highly crosslinked networks which exhibit low intrinsic ab- sorption in the wavelength range extending...losses. The tip is also coated with a PFA Teflon coating to minimize the sticking of the cauterized tissue onto the tip. The dedicated forceps is mounted

Sputtered pin amorphous silicon semi-conductor device and method therefor

DOEpatents

Moustakas, Theodore D.; Friedman, Robert A.

1983-11-22

A high efficiency amorphous silicon PIN semi-conductor device is constructed by the sequential sputtering of N, I and P layers of amorphous silicon and at least one semi-transparent ohmic electrode. A method of construction produces a PIN device, exhibiting enhanced physical integrity and facilitates ease of construction in a singular vacuum system and vacuum pump down procedure.

Periodicity of high-order neural functions

NASA Technical Reports Server (NTRS)

Kellaway, P.; Borda, R. P.; Frost, J. D.; Carrie, J. R. G.; Coats, A. C.

1973-01-01

The results of recent studies on higher order, integrative processes in the central nervous system are reported. Attempts were made to determine whether these processes exhibit any ongoing rhythmicity which might manifest itself in alterations of attention and alertness. Experiments were also designed to determine if a periodicity approximating that of the REM could be detected in various parameters of brain electrical activity.

Delgado Community College/Sears-Roebuck Keeping America Working. Math, Science and Technology Summer Youth Enrichment Program. Final Report.

ERIC Educational Resources Information Center

Delgado Community Coll., New Orleans, LA.

Recognizing the need for better preparation of high school students in mathematics, science, and technology, Delgado Community College and the Orleans Parish School System entered into an agreement for the provision of a summer enrichment program for minority students in grades 7 through 9 who had exhibited average or above average abilities in…

Millimeter wave propagation measurements using the ATS 5 satellite

NASA Technical Reports Server (NTRS)

Ippolito, L. J.

1972-01-01

The ATS 5 millimeter wave propagation experiment determines long- and short-term attenuation statistics of operational millimeter wavelength earthspace links as functions of defined meteorological conditions. A preliminary analysis of results with 15 GHz downlink and 32 GHz uplink frequency bands indicates that both frequency bands exhibit an excellent potential for utilization in reliable high data rate earth-space communications systems.

SERS encoded silver pyramids for attomolar detection of multiplexed disease biomarkers.

PubMed

Xu, Liguang; Yan, Wenjing; Ma, Wei; Kuang, Hua; Wu, Xiaoling; Liu, Liqaing; Zhao, Yuan; Wang, Libing; Xu, Chuanlai

2015-03-11

Three disease biomarkers can simultaneously be detected at the attomolar level because of a novel surface-enhanced Raman scattering (SERS) encoded silver pyramid sensing system. This newly designed pyramidal sensor with well-controlled geometry exhibits highly sensitive, selective, and reproducible SERS signals, and holds promising potential for biodetection applications. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Production of fibers by a floating zone fiber drawing technique

NASA Technical Reports Server (NTRS)

Haggerty, J. S.

1972-01-01

A CO2 laser heated, floating zone fiber growth process was developed. The resulting Al2O3 fibers exhibited the high room temperature strengths for large diameter fibers as well as high specific creep rupture strengths observed at 1093 C and 1316 C (2000 F and 2400 F). Single crystal fibers of TiC and Y2O3 were also grown. An optical system was developed to focus four CO2 laser beams onto the surface of a feed rod permitting the formation of highly controllable molten zones. The optical system permitted energy densities and angle of incidence of the beams to be adjusted over wide ranges. This optical system was incorporated into a controlled atmosphere, fiber growth furnace. The two principal advantages of a CO2 laser heat source are that ambient atmospheres may be freely selected to optimize fiber properties and the laser has no inherent temperature limit, so extremely high melting point materials can be melted. Both advantages were demonstrated.

High-refined carbohydrate diet promotes detrimental effects on alveolar bone and femur microarchitecture.

PubMed

Montalvany-Antonucci, C C; Zicker, M C; Macari, S; Pereira, T S F; Diniz, I M A; Andrade, I; Ferreira, A V M; Silva, T A

2018-02-01

The impact of high-refined carbohydrate (HC) diet on fat accumulation, adipokines secretion and systemic inflammation is well described. However, it remains unclear whether these processes affect bone remodeling. To investigate the effects of HC diet in the alveolar bone and femur parameters. BalbC mice were fed with conventional chow or HC diet for 12 weeks. After experimental time maxillae, femur, blood and white adipose tissue samples were collected. The animals feed with HC diet exhibited considerable increase of adiposity index and adipose tissue levels of TNF-α, IL-6, IL-10, IL-1β, TGF-β and leptin. Microtomography analysis of maxillary bone revealed horizontal alveolar bone loss and disruption of trabecular bone in mice feed with HC diet. These deleterious effects were correlated with a disturbance in bone cells and an augmented expression of Rankl/Opg ratio. Consistently, similar effects were observed in femurs, which also exhibited a reduction in bone maximum load and stiffness. Our data indicates that HC diet consumption disrupts bone remodeling process, favoring bone loss. Underlying mechanisms relies on fat tissue accumulation and also in systemic and local inflammation. Copyright © 2017 Elsevier Ltd. All rights reserved.

Kinetics of Cyclic Oxidation and Cracking and Finite Element Analysis of MA956 and Sapphire/MA956 Composite System

NASA Technical Reports Server (NTRS)

Lee, Kang N.; Arya, Vinod K.; Halford, Gary R.; Barrett, Charles A.

1996-01-01

Sapphire fiber-reinforced MA956 composites hold promise for significant weight savings and increased high-temperature structural capability, as compared to unreinforced MA956. As part of an overall assessment of the high-temperature characteristics of this material system, cyclic oxidation behavior was studied at 1093 C and 1204 C. Initially, both sets of coupons exhibited parabolic oxidation kinetics. Later, monolithic MA956 exhibited spallation and a linear weight loss, whereas the composite showed a linear weight gain without spallation. Weight loss of the monolithic MA956 resulted from the linking of a multiplicity of randomly oriented and closely spaced surface cracks that facilitated ready spallation. By contrast, cracking of the composite's oxide layer was nonintersecting and aligned nominally parallel with the orientation of the subsurface reinforcing fibers. Oxidative lifetime of monolithic MA956 was projected from the observed oxidation kinetics. Linear elastic, finite element continuum, and micromechanics analyses were performed on coupons of the monolithic and composite materials. Results of the analyses qualitatively agreed well with the observed oxide cracking and spallation behavior of both the MA956 and the Sapphire/MA956 composite coupons.

Growth mindset tempers the effects of poverty on academic achievement.

PubMed

Claro, Susana; Paunesku, David; Dweck, Carol S

2016-08-02

Two largely separate bodies of empirical research have shown that academic achievement is influenced by structural factors, such as socioeconomic background, and psychological factors, such as students' beliefs about their abilities. In this research, we use a nationwide sample of high school students from Chile to investigate how these factors interact on a systemic level. Confirming prior research, we find that family income is a strong predictor of achievement. Extending prior research, we find that a growth mindset (the belief that intelligence is not fixed and can be developed) is a comparably strong predictor of achievement and that it exhibits a positive relationship with achievement across all of the socioeconomic strata in the country. Furthermore, we find that students from lower-income families were less likely to hold a growth mindset than their wealthier peers, but those who did hold a growth mindset were appreciably buffered against the deleterious effects of poverty on achievement: students in the lowest 10th percentile of family income who exhibited a growth mindset showed academic performance as high as that of fixed mindset students from the 80th income percentile. These results suggest that students' mindsets may temper or exacerbate the effects of economic disadvantage on a systemic level.

The transport systems of Ventricaria ventricosa: hypotonic and hypertonic turgor regulation.

PubMed

Bisson, M A; Beilby, M J

2002-11-01

The time course of hypertonic and hypotonic turgor regulation was studied in Ventricaria (Valonia) using pressure probe and I/V(current-voltage) analysis. Of 11 cells, 9 exhibited hypertonic turgor regulation, ranging from 100% regulation in 150 min to 14% regulation (14% recovery of the decrease in turgor) in 314 min. Some cells began regulating immediately, others took up to 90 min to begin. The resting PD (potential difference) became more positive in most cells. The I/V characteristics became more nonlinear with high resistance between -150 and -20 mV and negative conductance region near -70 mV. Prolonged (16 sec) voltage clamps to negative levels (-100 to -150 mV) showed progressively more rapid current turn-off, but subsequent I/V characteristics were not affected. Clamping to +150 mV, however, abolished the high conductance between -50 and +100 mV to yield a uniform high resistance I/V characteristic, similar to that in high [K+]o. Decreasing illumination from 2.02 micromol sec(-1) m(-2) to 0.5 micromol sec(-1)1 m(-2) had a similar effect. Two out of a total of three cells exhibited hypotonic turgor regulation. Both cells started regulating within minutes and achieved near 50% regulation within 50 min. The PD became more negative. The I/V curves exhibited high resistance between +50 and +150 mV. The characteristics were similar to those in cells exposed to low [K+]o. Prolonged voltage clamps to both negative and positive levels showed slow current increase. Decreased illumination increased the membrane resistance.

CXCR1-mediated Neutrophil Degranulation and Fungal Killing Promotes Candida Clearance and Host Survival

PubMed Central

Swamydas, Muthulekha; Gao, Ji-Liang; Break, Timothy J.; Johnson, Melissa D.; Jaeger, Martin; Rodriguez, Carlos A.; Lim, Jean K.; Green, Nathaniel M.; Collar, Amanda L.; Fischer, Brett G.; Lee, Chyi-Chia Richard; Perfect, John R.; Alexander, Barbara D.; Kullberg, Bart-Jan; Netea, Mihai G.; Murphy, Philip M.; Lionakis, Michail S.

2016-01-01

Systemic Candida albicans infection causes high morbidity and mortality and is now the leading cause of nosocomial bloodstream infection in the US. Neutropenia is a major risk factor for poor outcome in infected patients; however, the molecular factors that mediate neutrophil trafficking and effector function during infection are poorly defined. Here, using a mouse model of systemic candidiasis, we found that the neutrophil-selective CXC chemokine receptor Cxcr1 and its ligand, Cxcl5, are highly induced in the Candida-infected kidney, the target organ in the model. To investigate the role of Cxcr1 in antifungal host defense in vivo, we generated Cxcr1−/− mice and analyzed their immune response to Candida. Mice lacking Cxcr1 exhibited decreased survival with enhanced Candida growth in the kidney and renal failure. Surprisingly, increased susceptibility of Cxcr1−/− mice to systemic candidiasis was not due to impaired neutrophil trafficking from the blood into the infected kidney but was the result of defective killing of the fungus by neutrophils that exhibited a cell-intrinsic decrease in degranulation. In humans, the mutant CXCR1 allele CXCR1-T276 results in impaired neutrophil degranulation and fungal killing and was associated with increased risk of disseminated candidiasis in infected patients. Together, our data demonstrate a biological function for mouse Cxcr1 in vivo and indicate that CXCR1-dependent neutrophil effector function is a critical innate protective mechanism of fungal clearance and host survival in systemic candidiasis. PMID:26791948

High-pressure electronic phase diagrams in FeSe1-xSx superconductors

NASA Astrophysics Data System (ADS)

Matsuura, Kohei; Arai, Yuki; Hosoi, Suguru; Ishida, Kousuke; Mizukami, Yuta; Watashige, Tatsuya; Kasahara, Shigeru; Matsuda, Yuji; Maejima, Naoyuki; Machida, Akihiko; Watanuki, Tetsu; Fukuda, Tatsuo; Uwatoko, Yoshiya; Shibauchi, Takasada

The spin fluctuations are believed to be related to the mechanism of the unconventional superconductors. On the other hand, many recent studies suggest that the nematic order that spontaneously breaks rotational symmetry of the system exists in the Fe-based superconductors and its quantum fluctuations may play an essential role for the superconductivity. However, this remains unclear because the nematic order usually coexists with the magnetic order. To solve this issue, FeSe exhibiting a nonmagnetic nematic order is a key system. Under pressure, this order is suppressed and concurrently magnetic order appears, which competes with high-Tc superconducting phase. In isovalent substitution system FeSe1-xSx, we found a nonmagnetic nematic quantum critical point. Here we report our recent high-pressure studies in high-quality single-crystalline FeSe1-xSx up to 8 GPa. We find a systematic change of the pressure phase diagram in FeSe by the S-substitution. Our results imply that the respective role of nematic and magnetic fluctuations can be elucidated from the precise control of pressure and substitution in this system.

Single-site trinuclear copper oxygen clusters in mordenite for selective conversion of methane to methanol.

PubMed

Grundner, Sebastian; Markovits, Monica A C; Li, Guanna; Tromp, Moniek; Pidko, Evgeny A; Hensen, Emiel J M; Jentys, Andreas; Sanchez-Sanchez, Maricruz; Lercher, Johannes A

2015-06-25

Copper-exchanged zeolites with mordenite structure mimic the nuclearity and reactivity of active sites in particulate methane monooxygenase, which are enzymes able to selectively oxidize methane to methanol. Here we show that the mordenite micropores provide a perfect confined environment for the highly selective stabilization of trinuclear copper-oxo clusters that exhibit a high reactivity towards activation of carbon-hydrogen bonds in methane and its subsequent transformation to methanol. The similarity with the enzymatic systems is also implied from the similarity of the reversible rearrangements of the trinuclear clusters occurring during the selective transformations of methane along the reaction path towards methanol, in both the enzyme system and copper-exchanged mordenite.

Studying Soft-matter and Biological Systems over a Wide Length-scale from Nanometer and Micrometer Sizes at the Small-angle Neutron Diffractometer KWS-2

PubMed Central

Radulescu, Aurel; Szekely, Noemi Kinga; Appavou, Marie-Sousai; Pipich, Vitaliy; Kohnke, Thomas; Ossovyi, Vladimir; Staringer, Simon; Schneider, Gerald J.; Amann, Matthias; Zhang-Haagen, Bo; Brandl, Georg; Drochner, Matthias; Engels, Ralf; Hanslik, Romuald; Kemmerling, Günter

2016-01-01

The KWS-2 SANS diffractometer is dedicated to the investigation of soft matter and biophysical systems covering a wide length scale, from nm to µm. The instrument is optimized for the exploration of the wide momentum transfer Q range between 1x10-4 and 0.5 Å-1 by combining classical pinhole, focusing (with lenses), and time-of-flight (with chopper) methods, while simultaneously providing high-neutron intensities with an adjustable resolution. Because of its ability to adjust the intensity and the resolution within wide limits during the experiment, combined with the possibility to equip specific sample environments and ancillary devices, the KWS-2 shows a high versatility in addressing the broad range of structural and morphological studies in the field. Equilibrium structures can be studied in static measurements, while dynamic and kinetic processes can be investigated over time scales between minutes to tens of milliseconds with time-resolved approaches. Typical systems that are investigated with the KWS-2 cover the range from complex, hierarchical systems that exhibit multiple structural levels (e.g., gels, networks, or macro-aggregates) to small and poorly-scattering systems (e.g., single polymers or proteins in solution). The recent upgrade of the detection system, which enables the detection of count rates in the MHz range, opens new opportunities to study even very small biological morphologies in buffer solution with weak scattering signals close to the buffer scattering level at high Q. In this paper, we provide a protocol to investigate samples with characteristic size levels spanning a wide length scale and exhibiting ordering in the mesoscale structure using KWS-2. We present in detail how to use the multiple working modes that are offered by the instrument and the level of performance that is achieved. PMID:28060296

A folate-integrated magnetic polymer micelle for MRI and dual targeted drug delivery

NASA Astrophysics Data System (ADS)

Ao, Lijiao; Wang, Bi; Liu, Peng; Huang, Liang; Yue, Caixia; Gao, Duyang; Wu, Chunlei; Su, Wu

2014-08-01

This paper devotes a novel micellar structure for cancer theranostics by incorporating magnetic and therapeutic functionalities into a natural sourced targeting polymer vehicle. Heparin-folic acid micelles taking advantage of both excellent loading capability and cancer targeting ability have been employed to simultaneously incorporate superparamagnetic iron oxide nanoparticles (SPIONs) and doxorubicin through an ultrasonication-assisted microemulsion method. In this system, folic acids not only take the responsibility of micelle construction, but also facilitate cellular uptake due to their specific reorganization by MCF-7 cells over-expressing folate receptors. The obtained micelles exhibit good colloidal stability, a high magnetic content, considerable drug loading and sustained in vitro drug release. These clustered SPIONs exhibited high r2 relaxivity (243.65 mM-1 s-1) and further served as efficient probes for MR imaging. Notably, the transport efficiency of these micelles could be significantly improved under an external magnetic field, owing to their quick magnetic response. As a result, the as-proposed micelle shows great potential in multimodal theranostics, including active targeting, MRI diagnosis and drug delivery.This paper devotes a novel micellar structure for cancer theranostics by incorporating magnetic and therapeutic functionalities into a natural sourced targeting polymer vehicle. Heparin-folic acid micelles taking advantage of both excellent loading capability and cancer targeting ability have been employed to simultaneously incorporate superparamagnetic iron oxide nanoparticles (SPIONs) and doxorubicin through an ultrasonication-assisted microemulsion method. In this system, folic acids not only take the responsibility of micelle construction, but also facilitate cellular uptake due to their specific reorganization by MCF-7 cells over-expressing folate receptors. The obtained micelles exhibit good colloidal stability, a high magnetic content, considerable drug loading and sustained in vitro drug release. These clustered SPIONs exhibited high r2 relaxivity (243.65 mM-1 s-1) and further served as efficient probes for MR imaging. Notably, the transport efficiency of these micelles could be significantly improved under an external magnetic field, owing to their quick magnetic response. As a result, the as-proposed micelle shows great potential in multimodal theranostics, including active targeting, MRI diagnosis and drug delivery. Electronic supplementary information (ESI) available. See DOI: 10.1039/c4nr02484b

Sex-specific patterns and deregulation of endocrine pathways in the gene expression profiles of Bangladeshi adults exposed to arsenic contaminated drinking water

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

Muñoz, Alexandra; Chervona, Yana; Hall, Megan

Arsenic contamination of drinking water occurs globally and is associated with numerous diseases including skin, lung and bladder cancers, and cardiovascular disease. Recent research indicates that arsenic may be an endocrine disruptor. This study was conducted to evaluate the nature of gene expression changes among males and females exposed to arsenic contaminated water in Bangladesh at high and low doses. Twenty-nine (55% male) Bangladeshi adults with water arsenic exposure ranging from 50 to 1000 μg/L were selected from the Folic Acid Creatinine Trial. RNA was extracted from peripheral blood mononuclear cells for gene expression profiling using Affymetrix 1.0 ST arrays.more » Differentially expressed genes were assessed between high and low exposure groups for males and females separately and findings were validated using quantitative real-time PCR. There were 534 and 645 differentially expressed genes (p < 0.05) in the peripheral blood mononuclear cells of males and females, respectively, when high and low water arsenic exposure groups were compared. Only 43 genes overlapped between the two sexes, with 29 changing in opposite directions. Despite the difference in gene sets both males and females exhibited common biological changes including deregulation of 17β-hydroxysteroid dehydrogenase enzymes, deregulation of genes downstream of Sp1 (specificity protein 1) transcription factor, and prediction of estrogen receptor alpha as a key hub in cardiovascular networks. Arsenic-exposed adults exhibit sex-specific gene expression profiles that implicate involvement of the endocrine system. Due to arsenic's possible role as an endocrine disruptor, exposure thresholds for arsenic may require different parameters for males and females. - Highlights: • Males and females exhibit unique gene expression changes in response to arsenic. • Only 23 genes are common among the differentially expressed genes for the sexes. • Male and female gene lists exhibit common biological implications. • Both sexes exhibit deregulation of cardiovascular and endocrine pathways.« less

Synthesis and Characterization of High c-axis ZnO Thin Film by Plasma Enhanced Chemical Vapor Deposition System and its UV Photodetector Application

PubMed Central

Chao, Chung-Hua; Wei, Da-Hua

2015-01-01

In this study, zinc oxide (ZnO) thin films with high c-axis (0002) preferential orientation have been successfully and effectively synthesized onto silicon (Si) substrates via different synthesized temperatures by using plasma enhanced chemical vapor deposition (PECVD) system. The effects of different synthesized temperatures on the crystal structure, surface morphologies and optical properties have been investigated. The X-ray diffraction (XRD) patterns indicated that the intensity of (0002) diffraction peak became stronger with increasing synthesized temperature until 400 oC. The diffraction intensity of (0002) peak gradually became weaker accompanying with appearance of (10-10) diffraction peak as the synthesized temperature up to excess of 400 oC. The RT photoluminescence (PL) spectra exhibited a strong near-band-edge (NBE) emission observed at around 375 nm and a negligible deep-level (DL) emission located at around 575 nm under high c-axis ZnO thin films. Field emission scanning electron microscopy (FE-SEM) images revealed the homogeneous surface and with small grain size distribution. The ZnO thin films have also been synthesized onto glass substrates under the same parameters for measuring the transmittance. For the purpose of ultraviolet (UV) photodetector application, the interdigitated platinum (Pt) thin film (thickness ~100 nm) fabricated via conventional optical lithography process and radio frequency (RF) magnetron sputtering. In order to reach Ohmic contact, the device was annealed in argon circumstances at 450 oC by rapid thermal annealing (RTA) system for 10 min. After the systematic measurements, the current-voltage (I-V) curve of photo and dark current and time-dependent photocurrent response results exhibited a good responsivity and reliability, indicating that the high c-axis ZnO thin film is a suitable sensing layer for UV photodetector application. PMID:26484561

Industrial activated sludge exhibit unique bacterial community composition at high taxonomic ranks.

PubMed

Ibarbalz, Federico M; Figuerola, Eva L M; Erijman, Leonardo

2013-07-01

Biological degradation of domestic and industrial wastewater by activated sludge depends on a common process of separation of the diverse self-assembled and self-sustained microbial flocs from the treated wastewater. Previous surveys of bacterial communities indicated the presence of a common core of bacterial phyla in municipal activated sludge, an observation consistent with the concept of ecological coherence of high taxonomic ranks. The aim of this work was to test whether this critical feature brings about a common pattern of abundance distribution of high bacterial taxa in industrial and domestic activated sludge, and to relate the bacterial community structure of industrial activated sludge with relevant operational parameters. We have applied 454 pyrosequencing of 16S rRNA genes to evaluate bacterial communities in full-scale biological wastewater treatment plants sampled at different times, including seven systems treating wastewater from different industries and one plant that treats domestic wastewater, and compared our datasets with the data from municipal wastewater treatment plants obtained by three different laboratories. We observed that each industrial activated sludge system exhibited a unique bacterial community composition, which is clearly distinct from the common profile of bacterial phyla or classes observed in municipal plants. The influence of process parameters on the bacterial community structure was evaluated using constrained analysis of principal coordinates (CAP). Part of the differences in the bacterial community structure between industrial wastewater treatment systems were explained by dissolved oxygen and pH. Despite the ecological relevance of floc formation for the assembly of bacterial communities in activated sludge, the wastewater characteristics are likely to be the major determinant that drives bacterial composition at high taxonomic ranks. Copyright © 2013 Elsevier Ltd. All rights reserved.

Modeling Surface Processes Occurring on Moons of the Outer Solar System

NASA Astrophysics Data System (ADS)

Umurhan, O. M.; White, O. L.; Moore, J. M.; Howard, A. D.; Schenk, P.

2016-12-01

A variety of processes, some with familiar terrestrial analogs, are known to take place on moon surfaces in the outer solar system. In this talk, we discuss the observed features of mass wasting and surface transport seen on both Jupiter's moon Calisto and one of Saturn's Trojan moons Helene. We provide a number of numerical models using upgraded version of MARSSIM in support of several hypotheses suggested on behalf of the observations made regarding these objects. Calisto exhibits rolling plains of low albedo materials surrounding relatively high jutting peaks harboring high albedo deposits. Our modeling supports the interpretation that Calisto's surface is a record of erosion driven by the sublimation of CO2 and H2O contained in the bedrock. Both solar insolation and surface re-radiation drives the sublimation leaving behind debris which we interpret to be the observed darkened regolith and, further, the high albedo peaks are water ice deposits on surface cold traps. On the other hand, the 45 km scale Helene, being a milligravity environment, exhibits mysterious looking streaks and grooves of very high albedo materials extending for several kilometers with a down-sloping grade of 7o-9o. Helene's cratered terrain also shows evidence of narrowed septa. The observed surface features suggest some type of advective processes are at play in this system. Our modeling lends support to the suggestion that Helene's surface materials behave as a Bingham plastic material - our flow modeling with such rheologies can reproduce the observed pattern of streakiness depending upon the smoothness of the underlying bedrock; the overall gradients observed; and the narrowed septa of inter-crater regions.

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

Ogura, Toshihiko, E-mail: t-ogura@aist.go.jp

Highlights: • We developed a high-sensitive frequency transmission electric-field (FTE) system. • The output signal was highly enhanced by applying voltage to a metal layer on SiN. • The spatial resolution of new FTE method is 41 nm. • New FTE system enables observation of the intact bacteria and virus in water. - Abstract: The high-resolution structural analysis of biological specimens by scanning electron microscopy (SEM) presents several advantages. Until now, wet bacterial specimens have been examined using atmospheric sample holders. However, images of unstained specimens in water using these holders exhibit very poor contrast and heavy radiation damage. Recently,more » we developed the frequency transmission electric-field (FTE) method, which facilitates the SEM observation of biological specimens in water without radiation damage. However, the signal detection system presents low sensitivity. Therefore, a high EB current is required to generate clear images, and thus reducing spatial resolution and inducing thermal damage to the samples. Here a high-sensitivity detection system is developed for the FTE method, which enhances the output signal amplitude by hundredfold. The detection signal was highly enhanced when voltage was applied to the metal layer on silicon nitride thin film. This enhancement reduced the EB current and improved the spatial resolution as well as the signal-to-noise ratio. The spatial resolution of a high-sensitive FTE system is 41 nm, which is considerably higher than previous FTE system. New FTE system can easily be utilised to examine various unstained biological specimens in water, such as living bacteria and viruses.« less

Biologically derived melanin electrodes in aqueous sodium-ion energy storage devices

PubMed Central

Kim, Young Jo; Wu, Wei; Chun, Sang-Eun; Whitacre, Jay F.; Bettinger, Christopher J.

2013-01-01

Biodegradable electronics represents an attractive and emerging paradigm in medical devices by harnessing simultaneous advantages afforded by electronically active systems and obviating issues with chronic implants. Integrating practical energy sources that are compatible with the envisioned operation of transient devices is an unmet challenge for biodegradable electronics. Although high-performance energy storage systems offer a feasible solution, toxic materials and electrolytes present regulatory hurdles for use in temporary medical devices. Aqueous sodium-ion charge storage devices combined with biocompatible electrodes are ideal components to power next-generation biodegradable electronics. Here, we report the use of biologically derived organic electrodes composed of melanin pigments for use in energy storage devices. Melanins of natural (derived from Sepia officinalis) and synthetic origin are evaluated as anode materials in aqueous sodium-ion storage devices. Na+-loaded melanin anodes exhibit specific capacities of 30.4 ± 1.6 mAhg−1. Full cells composed of natural melanin anodes and λ-MnO2 cathodes exhibit an initial potential of 1.03 ± 0.06 V with a maximum specific capacity of 16.1 ± 0.8 mAhg−1. Natural melanin anodes exhibit higher specific capacities compared with synthetic melanins due to a combination of beneficial chemical, electrical, and physical properties exhibited by the former. Taken together, these results suggest that melanin pigments may serve as a naturally occurring biologically derived charge storage material to power certain types of medical devices. PMID:24324163

Maternal “junk-food” feeding of rat dams alters food choices and development of the mesolimbic reward pathway in the offspring

PubMed Central

Ong, Z. Y.; Muhlhausler, B. S.

2011-01-01

Individuals exposed to high-fat, high-sugar diets before birth have an increased risk of obesity in later life. Recent studies have shown that these offspring exhibit increased preference for fat, leading to suggestions that perinatal exposure to high-fat, high-sugar foods results in permanent changes within the central reward system that increase the subsequent drive to overconsume palatable foods. The present study has determined the effect of a maternal “junk-food” diet on the expression of key components of the mesolimbic reward pathway in the offspring of rat dams at 6 wk and 3 mo of age. We show that offspring of junk-food-fed (JF) dams exhibit higher fat intake from weaning until at least 3 mo of age (males: 16±0.6 vs. 11±0.8 g/kg/d; females: 19±1.3 vs. 13±0.4 g/kg/d; P<0.01). mRNA expression of μ-opioid receptor (Mu) was 1.6-fold higher (P<0.01) and dopamine active transporter (DAT) was 2-fold lower (P<0.05) in JF offspring at 6 wk of age. By 3 mo, these differences were reversed, and Mu mRNA expression was 2.8-fold lower (P<0.01) and DAT mRNA expression was 1.9-fold higher (P<0.01) in the JF offspring. These findings suggest that perinatal exposure to high-fat, high-sugar diets results in altered development of the central reward system, resulting in increased fat intake and altered response of the reward system to excessive junk-food intake in postnatal life.—Ong, Z. Y., Muhlhausler, B. S. Maternal “junk-food” feeding of rat dams alters food choices and development of the mesolimbic reward pathway in the offspring. PMID:21427213

A high-fat diet differentially regulates glutathione phenotypes in the obesity-prone mouse strains DBA/2J, C57BL/6J, and AKR/J.

PubMed

Norris, Katie M; Okie, Whitney; Kim, Woo Kyun; Adhikari, Roshan; Yoo, Sarah; King, Stephanie; Pazdro, Robert

2016-12-01

The ubiquitous tripeptide glutathione (GSH) is a critical component of the endogenous antioxidant defense system. Tissue GSH concentrations and redox status (GSH/GSSG) are genetically controlled, but it is unclear whether interactions between genetic background and diet affect GSH homeostasis. The current study tested the hypothesis that a high-fat diet regulates GSH homeostasis in a manner dependent on genetic background. At 4 months of age, female mice representing 3 obesity-prone inbred strains-C57BL/6J (B6), DBA/2J (D2), and AKR/J (AKR)-were randomly assigned to consume a control (10% energy from fat) or high-fat (62% energy from fat) diet for 10 weeks (n=5/diet per strain). Tissue GSH levels, GSSG levels, and GSH/GSSG were quantified, and hepatic expression of GSH-related enzymes was evaluated by quantitative reverse transcription polymerase chain reaction. The high-fat diet caused a decrease in hepatic GSH/GSSG in D2 mice. In contrast, B6 mice exhibited a decrease in GSSG levels in the liver and kidney, as well as a resultant increase in renal GSH/GSSG. AKR mice also exhibited increased renal GSH/GSSG on a high-fat diet. Finally, the high-fat diet induced a unique gene expression response in D2 mice compared with B6 and AKR. The D2 response was characterized by up-regulation of glutamate-cysteine ligase modifier subunit and down-regulation of glutathione reductase, whereas the B6 and AKR responses were characterized by up-regulation of glutathione peroxidase 1. Two-way analysis of variance analyses confirmed several diet-strain interactions within the GSH system, and linear regression models highlighted relationships between body mass and GSH outcomes as well. Overall, our data indicate that dietary fat regulates the GSH system in a strain-dependent manner. Copyright © 2016 Elsevier Inc. All rights reserved.

Method of improving system performance and survivability through changing function

NASA Technical Reports Server (NTRS)

Hinchey, Michael G. (Inventor); Vassev, Emil I. (Inventor)

2012-01-01

A biologically-inspired system and method is provided for self-adapting behavior of swarm-based exploration missions, whereby individual components, for example, spacecraft, in the system can sacrifice themselves for the greater good of the entire system. The swarm-based system can exhibit emergent self-adapting behavior. Each component can be configured to exhibit self-sacrifice behavior based on Autonomic System Specification Language (ASSL).

[Utilization of polymeric micelle magnetic resonance imaging (MRI) contrast agent for theranostic system].

PubMed

Shiraishi, Kouichi

2013-01-01

We applied a polymeric micelle carrier system for the targeting of a magnetic resonance imaging (MRI) contrast agent. Prepared polymeric micelle MRI contrast agent exhibited a long circulation characteristic in blood, and considerable amount of the contrast agent was found to accumulate in colon 26 solid tumor by the EPR effect. The signal intensities of tumor area showed 2-folds increase in T1-weighted images at 24 h after i.v. injection. To observe enhancement of the EPR effect by Cderiv pretreatment on tumor targeting, we used the contrast agent for the evaluation by means of MRI. Cderiv pretreatment significantly enhanced tumor accumulation of the contrast agent. Interestingly, very high signal intensity in tumor region was found at 24 h after the contrast agent injection in Cderiv pretreated mice. The contrast agent visualized a microenvironmental change in tumor. These results indicate that the contrast agent exhibits potential use for tumor diagnostic agent. To combine with a polymeric micelle carrier system for therapeutic agent, the usage of the combination makes a new concept of "theranostic" for a better cancer treatment.

Alginate/hyaluronic acid hydrogel delivery system characteristics regulate the differentiation of periodontal ligament stem cells toward chondrogenic lineage.

PubMed

Ansari, Sahar; Diniz, Ivana M; Chen, Chider; Aghaloo, Tara; Wu, Benjamin M; Shi, Songtao; Moshaverinia, Alireza

2017-09-15

Cartilage tissue regeneration often presents a challenging clinical situation. Recently, it has been shown that Periodontal Ligament Stem Cells (PDLSCs) possess high chondrogenic differentiation capacity. In this study, we developed a stem cell delivery system based on alginate/hyaluronic acid (HA) loaded with TGF-β1 ligand, encapsulating PDLSCs; and investigated the chondrogenic differentiation of encapsulated cells in alginate/HA hydrogel microspheres in vitro and in vivo. The results showed that PDLSCs, as well as human bone marrow mesenchymal stem cells (hBMMSCs), as the positive control, were stained positive for both toluidine blue and alcian blue staining, while exhibiting high levels of gene expression related to chondrogenesis (Col II, Aggrecan and Sox-9), as assessed via qPCR. The quantitative PCR analyses exhibited that the chondrogenic differentiation of encapsulated MSCs can be regulated by the modulus of elasticity of hydrogel delivery system, confirming the vital role of the microenvironment, and the presence of inductive signals for viability and differentiation of MSCs. In vivo, histological and immunofluorescence staining for chondrogenic specific protein markers confirmed ectopic cartilage-like tissue regeneration inside transplanted hydrogels. PDLSCs presented significantly greater capability for chondrogenic differentiation than hBMMSCs (P < 0.05). Altogether, our findings confirmed that alginate/HA hydrogels encapsulating PDLSCs are a promising candidate for cartilage regeneration.

Parallel Computation of Flow in Heterogeneous Media Modelled by Mixed Finite Elements

NASA Astrophysics Data System (ADS)

Cliffe, K. A.; Graham, I. G.; Scheichl, R.; Stals, L.

2000-11-01

In this paper we describe a fast parallel method for solving highly ill-conditioned saddle-point systems arising from mixed finite element simulations of stochastic partial differential equations (PDEs) modelling flow in heterogeneous media. Each realisation of these stochastic PDEs requires the solution of the linear first-order velocity-pressure system comprising Darcy's law coupled with an incompressibility constraint. The chief difficulty is that the permeability may be highly variable, especially when the statistical model has a large variance and a small correlation length. For reasonable accuracy, the discretisation has to be extremely fine. We solve these problems by first reducing the saddle-point formulation to a symmetric positive definite (SPD) problem using a suitable basis for the space of divergence-free velocities. The reduced problem is solved using parallel conjugate gradients preconditioned with an algebraically determined additive Schwarz domain decomposition preconditioner. The result is a solver which exhibits a good degree of robustness with respect to the mesh size as well as to the variance and to physically relevant values of the correlation length of the underlying permeability field. Numerical experiments exhibit almost optimal levels of parallel efficiency. The domain decomposition solver (DOUG, http://www.maths.bath.ac.uk/~parsoft) used here not only is applicable to this problem but can be used to solve general unstructured finite element systems on a wide range of parallel architectures.

Self-Assembled CNT-Polymer Hybrids in Single-Walled Carbon Nanotubes Dispersed Aqueous Triblock Copolymer Solutions

NASA Astrophysics Data System (ADS)

Vijayaraghavan, D.; Manjunatha, A. S.; Poojitha, C. G.

2018-04-01

We have carried out scanning electron microscopy (SEM), differential scanning calorimetry (DSC), small angle X-ray scattering (SAXS), electrical conductivity, and 1H NMR studies as a function of temperature on single-walled carbon nanotubes (SWCNTs) dispersed aqueous triblock copolymer (P123) solutions. The single-walled carbon nanotubes in this system aggregate to form bundles, and the bundles aggregate to form net-like structures. Depending on the temperature and phases of the polymer, this system exhibits three different self-assembled CNT-polymer hybrids. We find CNT-unimer hybrid at low temperatures, CNT-micelle hybrid at intermediate temperatures wherein the polymer micelles are adsorbed in the pores of the CNT nets, and another type of CNT-micelle hybrid at high temperatures wherein the polymer micelles are adsorbed on the surface of the CNT bundles. Our DSC thermogram showed two peaks related to these structural changes in the CNT-polymer hybrids. Temperature dependence of the 1H NMR chemical shifts of the molecular groups of the polymer and the AC electrical conductivity of the composite also showed discontinuous changes at the temperatures at which the CNT-polymer hybrid's structural changes are seen. Interestingly, for a higher CNT concentration (0.5 wt.%) in the system, the aggregated polymer micelles adsorbed on the CNTs exhibit cone-like and cube-like morphologies at the intermediate and at high temperatures respectively.

Moving from hand to mouth: echo phonology and the origins of language

PubMed Central

Woll, Bencie

2014-01-01

Although the sign languages in use today are full human languages, certain of the features they share with gestures have been suggested to provide information about possible origins of human language. These features include sharing common articulators with gestures, and exhibiting substantial iconicity in comparison to spoken languages. If human proto-language was gestural, the question remains of how a highly iconic manual communication system might have been transformed into a primarily vocal communication system in which the links between symbol and referent are for the most part arbitrary. The hypothesis presented here focuses on a class of signs which exhibit: “echo phonology,” a repertoire of mouth actions which are characterized by “echoing” on the mouth certain of the articulatory actions of the hands. The basic features of echo phonology are introduced, and discussed in relation to various types of data. Echo phonology provides naturalistic examples of a possible mechanism accounting for part of the evolution of language, with evidence both of the transfer of manual actions to oral ones and the conversion of units of an iconic manual communication system into a largely arbitrary vocal communication system. PMID:25071636

Automatic generation of smart earthquake-resistant building system: Hybrid system of base-isolation and building-connection.

PubMed

Kasagi, M; Fujita, K; Tsuji, M; Takewaki, I

2016-02-01

A base-isolated building may sometimes exhibit an undesirable large response to a long-duration, long-period earthquake ground motion and a connected building system without base-isolation may show a large response to a near-fault (rather high-frequency) earthquake ground motion. To overcome both deficiencies, a new hybrid control system of base-isolation and building-connection is proposed and investigated. In this new hybrid building system, a base-isolated building is connected to a stiffer free wall with oil dampers. It has been demonstrated in a preliminary research that the proposed hybrid system is effective both for near-fault (rather high-frequency) and long-duration, long-period earthquake ground motions and has sufficient redundancy and robustness for a broad range of earthquake ground motions.An automatic generation algorithm of this kind of smart structures of base-isolation and building-connection hybrid systems is presented in this paper. It is shown that, while the proposed algorithm does not work well in a building without the connecting-damper system, it works well in the proposed smart hybrid system with the connecting damper system.

The significance of denitrifying polyphosphate accumulating organisms in biological nutrient removal activated sludge systems.

PubMed

Hu, Z R; Wentzel, M C; Ekama, G A

2002-01-01

In this paper the advantages and disadvantages of denitrifying PAOs (polyphosphate accumulating organisms) in conventional BNRAS (biological nutrient removal activated sludge) and external nitrification BNRAS (ENBNRAS) systems are evaluated, with experimental data exhibiting a range of anoxic P uptake from low (<10%) to very high (>60%). The results indicate that the specific denitrification rate of the PAOs on internally stored PHB COD is about 1/5th of that of the "ordinary" heterotrophic organisms on SBCOD, and the PAOs contribute little (maximum 20%) to the denitrification in BNRAS systems even when the anoxic P uptake is high (60% of the total P uptake). Considering the unpredictable nature of anoxic P uptake and the reduction in BEPR it causes compared with aerobic P uptake BEPR, it is concluded that anoxic P uptake does not add a significant advantage to the BNR system.

Integration process of fermentation and liquid biphasic flotation for lipase separation from Burkholderia cepacia.

PubMed

Sankaran, Revathy; Show, Pau Loke; Lee, Sze Ying; Yap, Yee Jiun; Ling, Tau Chuan

2018-02-01

Liquid Biphasic Flotation (LBF) is an advanced recovery method that has been effectively applied for biomolecules extraction. The objective of this investigation is to incorporate the fermentation and extraction process of lipase from Burkholderia cepacia using flotation system. Initial study was conducted to compare the performance of bacteria growth and lipase production using flotation and shaker system. From the results obtained, bacteria shows quicker growth and high lipase yield via flotation system. Integration process for lipase separation was investigated and the result showed high efficiency reaching 92.29% and yield of 95.73%. Upscaling of the flotation system exhibited consistent result with the lab-scale which are 89.53% efficiency and 93.82% yield. The combination of upstream and downstream processes in a single system enables the acceleration of product formation, improves the product yield and facilitates downstream processing. This integration system demonstrated its potential for biomolecules fermentation and separation that possibly open new opportunities for industrial production. Copyright © 2017 Elsevier Ltd. All rights reserved.

Small systems of Duffing oscillators and the Fermi-Pasta-Ulam-Tsingou system An examination of the possible reasons for the unusual stability of localized nonlinear excitations in these systems

NASA Astrophysics Data System (ADS)

Kashyap, Rahul; Westley, Alexandra; Sen, Surajit

The Duffing oscillator, a nonlinear oscillator with a potential energy with both quadratic and cubic terms, is known to show highly chaotic solutions in certain regions of its parameter space. Here, we examine the behaviors of small chains of harmonically and anharmonically coupled Duffing oscillators and show that these chains exhibit localized nonlinear excitations (LNEs) similar to the ones seen in the Fermi-Pasta-Ulam-Tsingou (FPUT) system. These LNEs demonstrate properties such as long-time energy localization, high periodicity, and slow energy leaking which rapidly accelerates upon frequency matching with the adjacent particles all of which have been observed in the FPUT system. Furthermore, by examining bifurcation diagrams, we will show that many qualitative properties of this system during the transition from weakly to strongly nonlinear behavior depend directly upon the frequencies associated with the individual Duffing oscillators.

Estimating biozone hydraulic conductivity in wastewater soil-infiltration systems using inverse numerical modeling.

PubMed

Bumgarner, Johnathan R; McCray, John E

2007-06-01

During operation of an onsite wastewater treatment system, a low-permeability biozone develops at the infiltrative surface (IS) during application of wastewater to soil. Inverse numerical-model simulations were used to estimate the biozone saturated hydraulic conductivity (K(biozone)) under variably saturated conditions for 29 wastewater infiltration test cells installed in a sandy loam field soil. Test cells employed two loading rates (4 and 8cm/day) and 3 IS designs: open chamber, gravel, and synthetic bundles. The ratio of K(biozone) to the saturated hydraulic conductivity of the natural soil (K(s)) was used to quantify the reductions in the IS hydraulic conductivity. A smaller value of K(biozone)/K(s,) reflects a greater reduction in hydraulic conductivity. The IS hydraulic conductivity was reduced by 1-3 orders of magnitude. The reduction in IS hydraulic conductivity was primarily influenced by wastewater loading rate and IS type and not by the K(s) of the native soil. The higher loading rate yielded greater reductions in IS hydraulic conductivity than the lower loading rate for bundle and gravel cells, but the difference was not statistically significant for chamber cells. Bundle and gravel cells exhibited a greater reduction in IS hydraulic conductivity than chamber cells at the higher loading rates, while the difference between gravel and bundle systems was not statistically significant. At the lower rate, bundle cells exhibited generally lower K(biozone)/K(s) values, but not at a statistically significant level, while gravel and chamber cells were statistically similar. Gravel cells exhibited the greatest variability in measured values, which may complicate design efforts based on K(biozone) evaluations for these systems. These results suggest that chamber systems may provide for a more robust design, particularly for high or variable wastewater infiltration rates.

The Impact on Space Radiation Requirements and Effects on ASIMS

NASA Technical Reports Server (NTRS)

Barnes, C.; Johnston, A.; Swift, G.

1995-01-01

The evolution of highly miniaturized electronic and mechanical systems will be accompanied by new problems and issues regarding the radiation response of these systems in the space environment. In this paper we discuss some of the more prominent radiation problems brought about by miniaturization. For example, autonomous micro-spacecraft will require large amounts of high density memory, most likely in the form of stacked, multichip modules of DRAM's, that must tolerate the radiation environment. However, advanced DRAM's (16 to 256 Mbit) are quite susceptible to radiation, particularly single event effects, and even exhibit new radiation phenomena that were not a problem for older, less dense memory chips. Another important trend in micro-spacecraft electronics is toward the use of low-voltage microelectronic systems that consume less power. However, the reduction in operating voltage also caries with it an increased susceptibility to radiation. In the case of application specific integrated microcircuits (ASIM's), advanced devices of this type, such as high density field programmable gate arrays (FPGA's) exhibit new single event effects (SEE), such as single particle reprogramming of anti-fuse links. New advanced bipolar circuits have been shown recently to degrade more rapidly in the low dose rate space environment than in the typical laboratory total dose radiation test used to qualify such devices. Thus total dose testing of these parts is no longer an appropriately conservative measure to be used for hardness assurance. We also note that the functionality of micromechanical Si-based devices may be altered due to the radiation-induced deposition of charge in the oxide passivation layers.

Syntheses, structure and magnetic properties of two vanadate garnets Ca{sub 5}M{sub 4}V{sub 6}O{sub 24} (M=Co, Ni)

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

Wang, Nannan; College of Materials Science and Engineering, Fuzhou University, Fuzhou, Fujian 350108; He, Zhangzhen, E-mail: hcz1988@hotmail.com

2015-08-15

Two vanadate compounds Ca{sub 5}M{sub 4}V{sub 6}O{sub 24} (M=Co, Ni) have been synthesized by a high-temperature solid-state reaction. The compounds are found to crystallize in the cubic system with a space group Ia-3d, which exhibit a typical garnet structural framework. Magnetic measurements show that Ca{sub 5}M{sub 4}V{sub 6}O{sub 24} (M=Co, Ni) exhibit similar magnetic behaviors, in which Ca{sub 5}Co{sub 4}V{sub 6}O{sub 24} possesses an antiferromagnetic ordering at T{sub N}=~6 K while Ca{sub 5}Ni{sub 4}V{sub 6}O{sub 24} shows an antiferromagnetic ordering at T{sub N}=~7 K. - Graphical abstract: Garnet vanadate compounds Ca{sub 5}M{sub 4}V{sub 6}O{sub 24} (M=Co, Ni) have been synthesizedmore » by a high-temperature solid-state reaction. Structural features and magnetic behaviors are also investigated. - Highlights: • New type of garnet vanadates Ca{sub 5}M{sub 4}V{sub 6}O{sub 24} (M=Co, Ni) are synthesized by a high-temperature solid-state reaction. • Structural features are confirmed by single crystal samples. • Magnetic behaviors are firstly investigated in the systems.« less

A method to validate quantitative high-frequency power doppler ultrasound with fluorescence in vivo video microscopy.

PubMed

Pinter, Stephen Z; Kim, Dae-Ro; Hague, M Nicole; Chambers, Ann F; MacDonald, Ian C; Lacefield, James C

2014-08-01

Flow quantification with high-frequency (>20 MHz) power Doppler ultrasound can be performed objectively using the wall-filter selection curve (WFSC) method to select the cutoff velocity that yields a best-estimate color pixel density (CPD). An in vivo video microscopy system (IVVM) is combined with high-frequency power Doppler ultrasound to provide a method for validation of CPD measurements based on WFSCs in mouse testicular vessels. The ultrasound and IVVM systems are instrumented so that the mouse remains on the same imaging platform when switching between the two modalities. In vivo video microscopy provides gold-standard measurements of vascular diameter to validate power Doppler CPD estimates. Measurements in four image planes from three mice exhibit wide variation in the optimal cutoff velocity and indicate that a predetermined cutoff velocity setting can introduce significant errors in studies intended to quantify vascularity. Consistent with previously published flow-phantom data, in vivo WFSCs exhibited three characteristic regions and detectable plateaus. Selection of a cutoff velocity at the right end of the plateau yielded a CPD close to the gold-standard vascular volume fraction estimated using IVVM. An investigator can implement the WFSC method to help adapt cutoff velocity to current blood flow conditions and thereby improve the accuracy of power Doppler for quantitative microvascular imaging. Copyright © 2014 World Federation for Ultrasound in Medicine & Biology. Published by Elsevier Inc. All rights reserved.

Scalable High-Performance Ultraminiature Graphene Micro-Supercapacitors by a Hybrid Technique Combining Direct Writing and Controllable Microdroplet Transfer.

PubMed

Shen, Daozhi; Zou, Guisheng; Liu, Lei; Zhao, Wenzheng; Wu, Aiping; Duley, Walter W; Zhou, Y Norman

2018-02-14

Miniaturization of energy storage devices can significantly decrease the overall size of electronic systems. However, this miniaturization is limited by the reduction of electrode dimensions and the reproducible transfer of small electrolyte drops. This paper reports first a simple scalable direct writing method for the production of ultraminiature microsupercapacitor (MSC) electrodes, based on femtosecond laser reduced graphene oxide (fsrGO) interlaced pads. These pads, separated by 2 μm spacing, are 100 μm long and 8 μm wide. A second stage involves the accurate transfer of an electrolyte microdroplet on top of each individual electrode, which can avoid any interference of the electrolyte with other electronic components. Abundant in-plane mesopores in fsrGO induced by a fs laser together with ultrashort interelectrode spacing enables MSCs to exhibit a high specific capacitance (6.3 mF cm -2 and 105 F cm -3 ) and ∼100% retention after 1000 cycles. An all graphene resistor-capacitor (RC) filter is also constructed by combining the MSC and a fsrGO resistor, which is confirmed to exhibit highly enhanced performance characteristics. This new hybrid technique combining fs laser direct writing and precise microdroplet transfer easily enables scalable production of ultraminiature MSCs, which is believed to be significant for practical application of micro-supercapacitor microelectronic systems.

Wide-Band, High-Quantum-Efficiency Photodetector

NASA Technical Reports Server (NTRS)

Jackson, Deborah; Wilson, Daniel; Stern, Jeffrey

2007-01-01

A design has been proposed for a photodetector that would exhibit a high quantum efficiency (as much as 90 percent) over a wide wavelength band, which would typically be centered at a wavelength of 1.55 m. This and similar photodetectors would afford a capability for detecting single photons - a capability that is needed for research in quantum optics as well as for the practical development of secure optical communication systems for distribution of quantum cryptographic keys. The proposed photodetector would be of the hot-electron, phonon-cooled, thin-film superconductor type. The superconducting film in this device would be a meandering strip of niobium nitride. In the proposed photodetector, the quantum efficiency would be increased through incorporation of optiA design has been proposed for a photodetector that would exhibit a high quantum efficiency (as much as 90 percent) over a wide wavelength band, which would typically be centered at a wavelength of 1.55 m. This and similar photodetectors would afford a capability for detecting single photons - a capability that is needed for research in quantum optics as well as for the practical development of secure optical communication systems for distribution of quantum cryptographic keys. The proposed photodetector would be of the hot-electron, phonon-cooled, thin-film superconductor type. The superconducting film in this device would be a meandering strip of niobium nitride. In the proposed photodetector, the quantum efficiency would be increased through incorporation of opti-

A comparative study of the mechanical performance of Glass and Glass/Carbon hybrid polymer composites at different temperature environments

NASA Astrophysics Data System (ADS)

Shukla, M. J.; Kumar, D. S.; Mahato, K. K.; Rathore, D. K.; Prusty, R. K.; Ray, B. C.

2015-02-01

Glass Fiber Reinforced Polymer (GFRP) composites have been widely accepted as high strength, low weight structural material as compared to their metallic counterparts. Some specific advanced high performance applications such as aerospace components still require superior specific strength and specific modulus. Carbon Fiber Reinforced Polymer (CFRP) composites exhibit superior specific strength and modulus but have a lower failure strain and high cost. Hence, the combination of both glass and carbon fiber in polymer composite may yield optimized mechanical properties. Further the in-service environment has a significant role on the mechanical performance of this class of materials. Present study aims to investigate the mechanical property of GFRP and Glass/Carbon (G/C hybrid) composites at room temperature, in-situ and ex-situ temperature conditions. In-situ testing at +70°C and +100°C results in significant loss in inter-laminar shear strength (ILSS) for both the composites as compared to room temperature. The ILSS was nearly equal for both the composite systems tested in-situ at +100°C and effect of fiber hybridisation was completely diminished there. At low temperature ex-situ conditioning significant reduction in ILSS was observed for both the systems. Further at -60°C G/C hybrid exhibited 32.4 % higher ILSS than GFRP. Hence this makes G/C hybrid a better choice of material in low temperature environmental applications.

Scalable domain decomposition solvers for stochastic PDEs in high performance computing

DOE PAGES

Desai, Ajit; Khalil, Mohammad; Pettit, Chris; ...

2017-09-21

Stochastic spectral finite element models of practical engineering systems may involve solutions of linear systems or linearized systems for non-linear problems with billions of unknowns. For stochastic modeling, it is therefore essential to design robust, parallel and scalable algorithms that can efficiently utilize high-performance computing to tackle such large-scale systems. Domain decomposition based iterative solvers can handle such systems. And though these algorithms exhibit excellent scalabilities, significant algorithmic and implementational challenges exist to extend them to solve extreme-scale stochastic systems using emerging computing platforms. Intrusive polynomial chaos expansion based domain decomposition algorithms are extended here to concurrently handle high resolutionmore » in both spatial and stochastic domains using an in-house implementation. Sparse iterative solvers with efficient preconditioners are employed to solve the resulting global and subdomain level local systems through multi-level iterative solvers. We also use parallel sparse matrix–vector operations to reduce the floating-point operations and memory requirements. Numerical and parallel scalabilities of these algorithms are presented for the diffusion equation having spatially varying diffusion coefficient modeled by a non-Gaussian stochastic process. Scalability of the solvers with respect to the number of random variables is also investigated.« less

Scalable domain decomposition solvers for stochastic PDEs in high performance computing

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

Desai, Ajit; Khalil, Mohammad; Pettit, Chris

Stochastic spectral finite element models of practical engineering systems may involve solutions of linear systems or linearized systems for non-linear problems with billions of unknowns. For stochastic modeling, it is therefore essential to design robust, parallel and scalable algorithms that can efficiently utilize high-performance computing to tackle such large-scale systems. Domain decomposition based iterative solvers can handle such systems. And though these algorithms exhibit excellent scalabilities, significant algorithmic and implementational challenges exist to extend them to solve extreme-scale stochastic systems using emerging computing platforms. Intrusive polynomial chaos expansion based domain decomposition algorithms are extended here to concurrently handle high resolutionmore » in both spatial and stochastic domains using an in-house implementation. Sparse iterative solvers with efficient preconditioners are employed to solve the resulting global and subdomain level local systems through multi-level iterative solvers. We also use parallel sparse matrix–vector operations to reduce the floating-point operations and memory requirements. Numerical and parallel scalabilities of these algorithms are presented for the diffusion equation having spatially varying diffusion coefficient modeled by a non-Gaussian stochastic process. Scalability of the solvers with respect to the number of random variables is also investigated.« less

A hybrid electrochemical device based on a synergetic inner combination of Li ion battery and Li ion capacitor for energy storage.

PubMed

Zheng, Jun-Sheng; Zhang, Lei; Shellikeri, Annadanesh; Cao, Wanjun; Wu, Qiang; Zheng, Jim P

2017-02-07

Li ion battery (LIB) and electrochemical capacitor (EC) are considered as the most widely used energy storage systems (ESSs) because they can produce a high energy density or a high power density, but it is a huge challenge to achieve both the demands of a high energy density as well as a high power density on their own. A new hybrid Li ion capacitor (HyLIC), which combines the advantages of LIB and Li ion capacitor (LIC), is proposed. This device can successfully realize a potential match between LIB and LIC and can avoid the excessive depletion of electrolyte during the charge process. The galvanostatic charge-discharge cycling tests reveal that at low current, the HyLIC exhibits a high energy density, while at high current, it demonstrates a high power density. Ragone plot confirms that this device can make a synergetic balance between energy and power and achieve a highest energy density in the power density range of 80 to 300 W kg -1 . The cycle life test proves that HyLIC exhibits a good cycle life and an excellent coulombic efficiency. The present study shows that HyLIC, which is capable of achieving a high energy density, a long cycle life and an excellent power density, has the potential to achieve the winning combination of a high energy and power density.

A hybrid electrochemical device based on a synergetic inner combination of Li ion battery and Li ion capacitor for energy storage

PubMed Central

Zheng, Jun-Sheng; Zhang, Lei; Shellikeri, Annadanesh; Cao, Wanjun; Wu, Qiang; Zheng, Jim P.

2017-01-01

Li ion battery (LIB) and electrochemical capacitor (EC) are considered as the most widely used energy storage systems (ESSs) because they can produce a high energy density or a high power density, but it is a huge challenge to achieve both the demands of a high energy density as well as a high power density on their own. A new hybrid Li ion capacitor (HyLIC), which combines the advantages of LIB and Li ion capacitor (LIC), is proposed. This device can successfully realize a potential match between LIB and LIC and can avoid the excessive depletion of electrolyte during the charge process. The galvanostatic charge-discharge cycling tests reveal that at low current, the HyLIC exhibits a high energy density, while at high current, it demonstrates a high power density. Ragone plot confirms that this device can make a synergetic balance between energy and power and achieve a highest energy density in the power density range of 80 to 300 W kg−1. The cycle life test proves that HyLIC exhibits a good cycle life and an excellent coulombic efficiency. The present study shows that HyLIC, which is capable of achieving a high energy density, a long cycle life and an excellent power density, has the potential to achieve the winning combination of a high energy and power density. PMID:28169329

Genomics of parallel adaptation at two timescales in Drosophila

PubMed Central

Begun, David J.

2017-01-01

Two interesting unanswered questions are the extent to which both the broad patterns and genetic details of adaptive divergence are repeatable across species, and the timescales over which parallel adaptation may be observed. Drosophila melanogaster is a key model system for population and evolutionary genomics. Findings from genetics and genomics suggest that recent adaptation to latitudinal environmental variation (on the timescale of hundreds or thousands of years) associated with Out-of-Africa colonization plays an important role in maintaining biological variation in the species. Additionally, studies of interspecific differences between D. melanogaster and its sister species D. simulans have revealed that a substantial proportion of proteins and amino acid residues exhibit adaptive divergence on a roughly few million years long timescale. Here we use population genomic approaches to attack the problem of parallelism between D. melanogaster and a highly diverged conger, D. hydei, on two timescales. D. hydei, a member of the repleta group of Drosophila, is similar to D. melanogaster, in that it too appears to be a recently cosmopolitan species and recent colonizer of high latitude environments. We observed parallelism both for genes exhibiting latitudinal allele frequency differentiation within species and for genes exhibiting recurrent adaptive protein divergence between species. Greater parallelism was observed for long-term adaptive protein evolution and this parallelism includes not only the specific genes/proteins that exhibit adaptive evolution, but extends even to the magnitudes of the selective effects on interspecific protein differences. Thus, despite the roughly 50 million years of time separating D. melanogaster and D. hydei, and despite their considerably divergent biology, they exhibit substantial parallelism, suggesting the existence of a fundamental predictability of adaptive evolution in the genus. PMID:28968391

Selection of mRNA 5'-untranslated region sequence with high translation efficiency through ribosome display

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

Mie, Masayasu; Shimizu, Shun; Takahashi, Fumio

2008-08-15

The 5'-untranslated region (5'-UTR) of mRNAs functions as a translation enhancer, promoting translation efficiency. Many in vitro translation systems exhibit a reduced efficiency in protein translation due to decreased translation initiation. The use of a 5'-UTR sequence with high translation efficiency greatly enhances protein production in these systems. In this study, we have developed an in vitro selection system that favors 5'-UTRs with high translation efficiency using a ribosome display technique. A 5'-UTR random library, comprised of 5'-UTRs tagged with a His-tag and Renilla luciferase (R-luc) fusion, were in vitro translated in rabbit reticulocytes. By limiting the translation period, onlymore » mRNAs with high translation efficiency were translated. During translation, mRNA, ribosome and translated R-luc with His-tag formed ternary complexes. They were collected with translated His-tag using Ni-particles. Extracted mRNA from ternary complex was amplified using RT-PCR and sequenced. Finally, 5'-UTR with high translation efficiency was obtained from random 5'-UTR library.« less

High-dimensional Controlled-phase Gate Between a 2 N -dimensional Photon and N Three-level Artificial Atoms

NASA Astrophysics Data System (ADS)

Ma, Yun-Ming; Wang, Tie-Jun

2017-10-01

Higher-dimensional quantum system is of great interest owing to the outstanding features exhibited in the implementation of novel fundamental tests of nature and application in various quantum information tasks. High-dimensional quantum logic gate is a key element in scalable quantum computation and quantum communication. In this paper, we propose a scheme to implement a controlled-phase gate between a 2 N -dimensional photon and N three-level artificial atoms. This high-dimensional controlled-phase gate can serve as crucial components of the high-capacity, long-distance quantum communication. We use the high-dimensional Bell state analysis as an example to show the application of this device. Estimates on the system requirements indicate that our protocol is realizable with existing or near-further technologies. This scheme is ideally suited to solid-state integrated optical approaches to quantum information processing, and it can be applied to various system, such as superconducting qubits coupled to a resonator or nitrogen-vacancy centers coupled to a photonic-band-gap structures.

Design of flexible polyphenylene proton-conducting membrane for next-generation fuel cells

PubMed Central

Miyake, Junpei; Taki, Ryunosuke; Mochizuki, Takashi; Shimizu, Ryo; Akiyama, Ryo; Uchida, Makoto; Miyatake, Kenji

2017-01-01

Proton exchange membrane fuel cells (PEMFCs) are promising devices for clean power generation in automotive, stationary, and portable applications. Perfluorosulfonic acid (PFSA) ionomers (for example, Nafion) have been the benchmark PEMs; however, several problems, including high gas permeability, low thermal stability, high production cost, and environmental incompatibility, limit the widespread dissemination of PEMFCs. It is believed that fluorine-free PEMs can potentially address all of these issues; however, none of these membranes have simultaneously met the criteria for both high performance (for example, proton conductivity) and durability (for example, mechanical and chemical stability). We present a polyphenylene-based PEM (SPP-QP) that fulfills the required properties for fuel cell applications. The newly designed PEM exhibits very high proton conductivity, excellent membrane flexibility, low gas permeability, and extremely high stability, with negligible degradation even under accelerated degradation conditions, which has never been achieved with existing fluorine-free PEMs. The polyphenylene PEM also exhibits reasonably high fuel cell performance, with excellent durability under practical conditions. This new PEM extends the limits of existing fluorine-free proton-conductive materials and will help to realize the next generation of PEMFCs via cost reduction as well as the performance improvement compared to the present PFSA-based PEMFC systems. PMID:29075671

Plant-produced anti-dengue virus monoclonal antibodies exhibit reduced antibody-dependent enhancement of infection activity.

PubMed

Dent, Matthew; Hurtado, Jonathan; Paul, Amber M; Sun, Haiyan; Lai, Huafang; Yang, Ming; Esqueda, Adrian; Bai, Fengwei; Steinkellner, Herta; Chen, Qiang

2016-12-01

The mAb E60 has the potential to be a desirable therapeutic molecule since it efficiently neutralizes all four serotypes of dengue virus (DENV). However, mammalian-cell-produced E60 exhibits antibody-dependent enhancement of infection (ADE) activity, rendering it inefficacious in vivo, and treated animals more susceptible to developing more severe diseases during secondary infection. In this study, we evaluated a plant-based expression system for the production of therapeutically suitable E60. The mAb was transiently expressed in Nicotiana benthamianaWT and a ∆XFT line, a glycosylation mutant lacking plant-specific N-glycan residues. The mAb was efficiently expressed and assembled in leaves and exhibited highly homogenous N-glycosylation profiles, i.e. GnGnXF3 or GnGn structures, depending on the expression host. Both E60 glycovariants demonstrated equivalent antigen-binding specificity and in vitro neutralization potency against DENV serotypes 2 and 4 compared with their mammalian-cell-produced counterpart. By contrast, plant-produced E60 exhibited reduced ADE activity in Fc gamma receptor expressing human cells. Our results suggest the ability of plant-produced antibodies to minimize ADE, which may lead to the development of safe and highly efficacious antibody-based therapeutics against DENV and other ADE-prone viral diseases. Our study provides so far unknown insight into the relationship between mAb N-glycosylation and ADE, which contributes to our understanding of how sugar moieties of antibodies modulate Fc-mediated functions and viral pathogenesis.

High-Performance Ru1 /CeO2 Single-Atom Catalyst for CO Oxidation: A Computational Exploration.

PubMed

Li, Fengyu; Li, Lei; Liu, Xinying; Zeng, Xiao Cheng; Chen, Zhongfang

2016-10-18

By means of density functional theory computations, we examine the stability and CO oxidation activity of single Ru on CeO 2 (111), TiO 2 (110) and Al 2 O 3 (001) surfaces. The heterogeneous system Ru 1 /CeO 2 has very high stability, as indicated by the strong binding energies and high diffusion barriers of a single Ru atom on the ceria support, while the Ru atom is rather mobile on TiO 2 (110) and Al 2 O 3 (001) surfaces and tends to form clusters, excluding these systems from having a high efficiency per Ru atom. The Ru 1 /CeO 2 exhibits good catalytic activity for CO oxidation via the Langmuir-Hinshelwood mechanism, thus is a promising single-atom catalyst. © 2016 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

High-pressure electrical resistivity studies for Ba1-xCsxFe2Se3

NASA Astrophysics Data System (ADS)

Kawashima, C.; Soeda, H.; Takahashi, H.; Hawai, T.; Nambu, Y.; Sato, T. J.; Hirata, Y.; Ohgushi, K.

2017-10-01

High-pressure electrical resistance measurements were performed for iron-based ladder material Ba1-xCsxFe2Se3 (x = 0.25 and 0.65) using a diamond anvil cell (DAC). Recent high-pressure study revealed that iron-based ladder material BaFe2S3 exhibits an insulator-metal transition and superconductivity, and this discovery would provide important insight for understanding the mechanism of iron-based superconductors. Therefore, it is intriguing to investigate the high-pressure properties for the iron-based ladder material Ba1-xCsxFe2Se3 system. The parent compounds BaFe2Se3 and CsFe2Se3 show insulating and magnetic ordering features. For Ba1-xCsxFe2Se3 system, no magnetic ordering is observed for x = 0.25 and minimum charge gap was estimated for x = 0.65. The insulator-metal transitions are observed in both materials.

High-pressure electrical resistivity studies for Ba1-xCsxFe2Se3

NASA Astrophysics Data System (ADS)

Kawashima, C.; Soeda, H.; Takahashi, H.; Hawai, T.; Nambu, Y.; Sato, T. J.; Hirata, Y.; Ohgushi, K.

2017-10-01

High-pressure electrical resistance measurements were performed for iron-based ladder material Ba1-xCsxFe2Se3 (x = 0.25 and 0.65) using a diamond anvil cell (DAC). Recent high-pressure study revealed that iron-based ladder material BaFe2S3 exhibits an insulator- metal transition and superconductivity, and this discovery would provide important insight for understanding the mechanism of iron-based superconductors. Therefore, it is intriguing to investigate the high-pressure properties for the iron-based ladder material Ba1-xCsxFe2Se3 system. The parent compounds BaFe2Se3 and CsFe2Se3 show insulating and magnetic ordering features. For Ba1-xCsxFe2Se3 system, no magnetic ordering is observed for x = 0.25 and minimum charge gap was estimated for x = 0.65. The insulator-metal transitions are observed in both materials.

Effects of Hatchery Rearing on the Structure and Function of Salmonid Mechanosensory Systems.

PubMed

Brown, Andrew D; Sisneros, Joseph A; Jurasin, Tyler; Coffin, Allison B

2016-01-01

This paper reviews recent studies on the effects of hatchery rearing on the auditory and lateral line systems of salmonid fishes. Major conclusions are that (1) hatchery-reared juveniles exhibit abnormal lateral line morphology (relative to wild-origin conspecifics), suggesting that the hatchery environment affects lateral line structure, perhaps due to differences in the hydrodynamic conditions of hatcheries versus natural rearing environments, and (2) hatchery-reared salmonids have a high proportion of abnormal otoliths, a condition associated with reduced auditory sensitivity and suggestive of inner ear dysfunction.

Low-dimensional chaos in turbulence

NASA Technical Reports Server (NTRS)

Vastano, John A.

1989-01-01

Direct numerical simulations are being performed on two different fluid flows in an attempt to discover the mechanism underlying the transition to turbulence in each. The first system is Taylor-Couette flow; the second, two-dimensional flow over an airfoil. Both flows exhibit a gradual transition to high-dimensional turbulence through low-dimensional chaos. The hope is that the instabilities leading to chaos will be easier to relate to physical processes in this case, and that the understanding of these mechanisms can then be applied to a wider array of turbulent systems.

The Urbana coherent-scatter radar: Synthesis and first results

NASA Technical Reports Server (NTRS)

Gibbs, K. P.; Bowhill, S. A.

1979-01-01

A coherent scatter radar system was synthesized and several hundred hours of echo power and line of sight velocity data obtained. The coherent scatter radar utilizes a diode array and components from meteor radar. The receiving system permits a time resolution of one minute in the data. Echo power from the D region shows a high degree of variability from day to day. Examples of changes in power level at shorter time scales are observed. Velocity data show the existence of gravity waves and occasionally exhibit vertical standing wave characteristics.

Growth of High Purity Oxygen-Free Silicon by Cold Crucible Techniques.

DTIC Science & Technology

1982-06-01

Liquid Metals (A Review). High Temp.-High Pressures 2(6), 583-586, 1970. 1971 Knights, C.F. and Perkins, R. Levitation Melting of Uranium Mono- Carbide . J...content - typically I PPM or less. c) The crystals grown exhibited a high level of carbon contamination (2-30 PPM ) which we believe, is caused by the...grown from melts confined in the cold crucible exhibit an unusually low oxygen content - typically 1 PPM or less. c.) The crystals grown exhibited a

Antioxidative properties of harmane and beta-carboline alkaloids.

PubMed

Tse, S Y; Mak, I T; Dickens, B F

1991-07-15

beta-Carboline alkaloids are derived as a result of condensation between indoleamine (e.g. tryptamine) and short-chain carboxylic acid (e.g. pyruvic acid) or aldehyde (e.g. acetaldehyde), a reaction that occurs readily at room temperature. These compounds have been found endogenously in human and animal tissues and may be formed as a byproduct of secondary metabolism: their endogenous functions however, are not well understood. Indoles and tryptophan derivatives exhibit antioxidative actions by scavenging free radicals and forming resonance stabilized indolyl radicals. Harmane and related compounds exhibited concentration-dependent inhibition of lipid peroxidation (measured as thiobarbiturate reactive products) in a hepatic microsomal preparation incubated with either enzymatic dependent (Fe3+ ADP/NADPH) or non-enzymatic dependent (Fe3+ ADP/dihydroxyfumarate) oxygen radical producing systems. Alkaloids with hydroxyl substitution and a partially desaturated pyridyl ring were found to have the highest antioxidative potencies. Substitution of a hydroxyl group by a methoxyl group at the 6-position resulted in a decrease of greater than 10-fold in the antioxidative activities. Harmane showed high efficacy in an enzymatic system but low efficacy in a non-enzymatic system. The antioxidative effects of harmane in the former system may be attributed to its ability to inhibit oxidative enzymes in the microsomal system. These results suggest that beta-carbolines may also serve as endogenous antioxidants.

Immunotoxicity and environment: immunodysregulation and systemic inflammation in children.

PubMed

Calderón-Garcidueñas, Lilian; Macías-Parra, Mercedes; Hoffmann, Hans J; Valencia-Salazar, Gildardo; Henríquez-Roldán, Carlos; Osnaya, Norma; Monte, Ofelia Camacho-Del; Barragán-Mejía, Gerardo; Villarreal-Calderon, Rodolfo; Romero, Lina; Granada-Macías, Margarita; Torres-Jardón, Ricardo; Medina-Cortina, Humberto; Maronpot, Robert R

2009-02-01

Environmental pollutants, chemicals, and drugs have an impact on children's immune system development. Mexico City (MC) children exposed to significant concentrations of air pollutants exhibit chronic respiratory inflammation, systemic inflammation, neuroinflammation, and cognitive deficits. We tested the hypothesis that exposure to severe air pollution plays a role in the immune responses of asymptomatic, apparently healthy children. Blood measurements for markers of immune function, inflammatory mediators, and molecules interacting with the lipopolysaccharide recognition complex were obtained from two cohorts of matched children (aged 9.7 +/- 1.2 years) from southwest Mexico City (SWMC) (n = 66) and from a control city (n = 93) with criteria pollutant levels below current standards. MC children exhibited significant decreases in the numbers of natural killer cells (p = .003) and increased numbers of mCD14+ monocytes (p < .001) and CD8+ cells (p = .02). Lower concentrations of interferon gamma (p = .009) and granulocyte-macrophage colony-stimulating factor (p < .001), an endotoxin tolerance-like state, systemic inflammation, and an anti-inflammatory response were also present in the highly exposed children. C-reactive protein and the prostaglandin E metabolite levels were positively correlated with twenty-four- and forty-eight-hour cumulative concentrations of PM(2.5). Exposure to urban air pollution is associated with immunodysregulation and systemic inflammation in children and is a major health threat.

Internal Representation and Memory Formation of Odor Preference Based on Oscillatory Activities in a Terrestrial Slug

ERIC Educational Resources Information Center

Sekiguchi, Tatsuhiko; Furudate, Hiroyuki; Kimura, Tetsuya

2010-01-01

The terrestrial slug "Limax" exhibits a highly developed ability to learn odors with a small nervous system. When a fluorescent dye, Lucifer Yellow (LY), is injected into the slug's body cavity after odor-taste associative conditioning, a group of neurons in the procerebral (PC) lobe, an olfactory center of the slug, is labeled by LY. We examined…

A New Room-Temperature Liquid, High-Performance Tricyanate Ester

DTIC Science & Technology

2010-01-01

addition of thermoplastic modifiers. Taken together, these results indicate that mono- mer 7 exhibits very favorable processing characteristics for a...significantly exceed those of epoxy resins with corresponding temperature-dependent monomer viscos- ity characteristics .4(a) In addition, cyanate ester...temperature, favorable solubility and viscos- ity characteristics for the addition of comonomers4(b) or toughening agents.4(c) Cyanate ester monomer systems

Laboratory experiments to estimate interception of infrared radiation by tree canopies

Treesearch

Bill J. Mathews; Eva K. Strand; Alistair M. S. Smith; Andrew T. Hudak; Matthew B. Dickinson; Robert L. Kremens

2016-01-01

Fire is a key earth-system and Anthropocene process (Bowman et al. 2009; Smith et al. 2016a). Fire impacts on the global carbon (C) cycle from both anthropogenic and natural sources, with 1350-3400 Tg C emitted from land-use changes, agricultural practices and residential uses, and 2750-4600 Tg C emitted in wildfire events, which exhibit high interannual variability (...

Handheld isotope identification system

DOEpatents

Frankle, Christen M [Los Alamos, NM; Becker, John A [Alameda, CA; Cork,; Christopher, P [Pleasant Hill, CA; Madden, Norman W [Livermore, CA

2007-01-09

A portable radiation detector using a high-purity germanium crystal as the sensing device. The crystal is fabricated such that it exhibits a length to width ratio greater than 1:1 and is oriented within the detector to receive radiation along the width of said crystal. The crystal is located within a container pressurized with ultra-pure nitrogen, and the container is located within a cryostat under vacuum.

[Policies for influenza control in Chile].

PubMed

Astudillo Olivares, Pedro

2006-03-01

Influenza control is based in two main components: a surveillance system and vaccination. In both aspects Chile has conquered high internacional standards and can exhibit the best results in the Region, obtaining a significant reduction in mortality attributable to influenza and pneumonia as vaccine coverage has increased over 11% of the total population. Pandemic influenza menace is permanent and obliges national authorities to prepare special strategies to face it.

International SAMPE Symposium and Exhibition, 36th, San Diego, CA, Apr. 15-18, 1991, Proceedings. Books 1 2

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

Stinson, J.; Adsit, R.; Gordaninejad, F.

This symposium presents papers in the fields of the design and development of space system structures, advanced textile preforming, low-cost processing of materials, and nondestructive testing. Also presented are adhesive and bonding technologies, resin transfer molding, filament winding, high-temperature composites, thermoplastic material properties, composites for marine environments, and thermoplastic processes and applications.

High-throughput and high-yield fabrication of uniaxially-aligned chitosan-based nanofibers by centrifugal electrospinning

PubMed Central

Erickson, Ariane E.; Edmondson, Dennis; Chang, Fei-Chien; Wood, Dave; Gong, Alex; Levengood, Sheeny Lan; Zhang, Miqin

2016-01-01

The inability to produce large quantities of nanofibers has been a primary obstacle in advancement and commercialization of electrospinning technologies, especially when aligned nanofibers are desired. Here, we present a high-throughput centrifugal electrospinning (HTP-CES) system capable of producing a large number of highly-aligned nanofiber samples with high-yield and tunable diameters. The versatility of the design was revealed when bead-less nanofibers were produced from copolymer chitosan/polycaprolactone (C-PCL) solutions despite variations in polymer blend composition or spinneret needle gauge. Compared to conventional electrospinning techniques, fibers spun with the HTP-CES not only exhibited superior alignment, but also better diameter uniformity. Nanofiber alignment was quantified using Fast Fourier Transform (FFT) analysis. In addition, a concave correlation between the needle diameter and resultant fiber diameter was identified. This system can be easily scaled up for industrial production of highly-aligned nanofibers with tunable diameters that can potentially meet the requirements for various engineering and biomedical applications. PMID:26428148

Energy performance of a ventilation system for a block of apartments with a ground source heat pump as generation system

NASA Astrophysics Data System (ADS)

Lucchi, M.; Lorenzini, M.; Valdiserri, P.

2017-01-01

This work presents a numerical simulation of the annual performance of two different systems: a traditional one composed by a gas boiler-chiller pair and one consisting of a ground source heat pump (GSHP) both coupled to two thermal storage tanks. The systems serve a bloc of flats located in northern Italy and are assessed over a typical weather year, covering both the heating and cooling seasons. The air handling unit (AHU) coupled with the GSHP exhibits excellent characteristics in terms of temperature control, and has high performance parameters (EER and COP), which make conduction costs about 30% lower than those estimated for the traditional plant.

Towards energy efficient operation of Heating, Ventilation and Air Conditioning systems via advanced supervisory control design

NASA Astrophysics Data System (ADS)

Oswiecinska, A.; Hibbs, J.; Zajic, I.; Burnham, K. J.

2015-11-01

This paper presents conceptual control solution for reliable and energy efficient operation of heating, ventilation and air conditioning (HVAC) systems used in large volume building applications, e.g. warehouse facilities or exhibition centres. Advanced two-level scalable control solution, designed to extend capabilities of the existing low-level control strategies via remote internet connection, is presented. The high-level, supervisory controller is based on Model Predictive Control (MPC) architecture, which is the state-of-the-art for indoor climate control systems. The innovative approach benefits from using passive heating and cooling control strategies for reducing the HVAC system operational costs, while ensuring that required environmental conditions are met.

Minimal hardware Bluetooth tracking for long-term at-home elder supervision.

PubMed

Kelly, Damian; McLoone, Sean; Farrell, Ronan

2010-01-01

The ability to automatically detect the location of an elder within their own home is a significant enabler of remote elder supervision and interaction applications. This location information is typically generated via a myriad of sensors throughout the home environment. Even with high sensor redundancy, there are still situations where traditional elder monitoring systems are unable to resolve the location of the elder. This work develops a minimal infrastructure radio-frequency localisation system for long-term elder location tracking. An RFID room-labelling technique is employed and with it, the localisation system developed in this work is shown to exhibit superior performance to more traditional localisation systems in realistic long-term deployments.

Impact of seasonality upon the dynamics of a novel pathogen in a seabird colony

NASA Astrophysics Data System (ADS)

O'Regan, S. M.

2008-11-01

A seasonally perturbed variant of the basic Susceptible-Infected-Recovered (SIR) model in epidemiology is considered in this paper. The effect of seasonality on an IR system of ordinary differential equations describing the dynamics of a novel pathogen, e.g., highly pathogenic avian influenza, in a seabird colony is investigated. The method of Lyapunov functions is used to determine the long-term behaviour of this system. Numerical simulations of the seasonally perturbed IR system indicate that the system exhibits complex dynamics as the amplitude of the seasonal perturbation term is increased. These findings suggest that seasonality may exert a considerable effect on the dynamics of epidemics in a seabird colony.

Facilitated charge transport in ternary interconnected electrodes for flexible supercapacitors with excellent power characteristics.

PubMed

Chen, Wanjun; He, Yongmin; Li, Xiaodong; Zhou, Jinyuan; Zhang, Zhenxing; Zhao, Changhui; Gong, Chengshi; Li, Shuankui; Pan, Xiaojun; Xie, Erqing

2013-12-07

Flexible and high performance supercapacitors are very critical in modern society. In order to develop the flexible supercapacitors with high power density, free-standing and flexible three-dimensional graphene/carbon nanotubes/MnO2 (3DG/CNTs/MnO2) composite electrodes with interconnected ternary 3D structures were fabricated, and the fast electron and ion transport channels were effectively constructed in the rationally designed electrodes. Consequently, the obtained 3DG/CNTs/MnO2 composite electrodes exhibit superior specific capacitance and rate capability compared to 3DG/MnO2 electrodes. Furthermore, the 3DG/CNTs/MnO2 based asymmetric supercapacitor demonstrates the maximum energy and power densities of 33.71 W h kg(-1) and up to 22,727.3 W kg(-1), respectively. Moreover, the asymmetric supercapacitor exhibits excellent cycling stability with 95.3% of the specific capacitance maintained after 1000 cycle tests. Our proposed synthesis strategy to construct the novel ternary 3D structured electrodes can be efficiently applied to other high performance energy storage/conversion systems.

Deterministic Coupling of Quantum Emitters in 2D Materials to Plasmonic Nanocavity Arrays.

PubMed

Tran, Toan Trong; Wang, Danqing; Xu, Zai-Quan; Yang, Ankun; Toth, Milos; Odom, Teri W; Aharonovich, Igor

2017-04-12

Quantum emitters in two-dimensional materials are promising candidates for studies of light-matter interaction and next generation, integrated on-chip quantum nanophotonics. However, the realization of integrated nanophotonic systems requires the coupling of emitters to optical cavities and resonators. In this work, we demonstrate hybrid systems in which quantum emitters in 2D hexagonal boron nitride (hBN) are deterministically coupled to high-quality plasmonic nanocavity arrays. The plasmonic nanoparticle arrays offer a high-quality, low-loss cavity in the same spectral range as the quantum emitters in hBN. The coupled emitters exhibit enhanced emission rates and reduced fluorescence lifetimes, consistent with Purcell enhancement in the weak coupling regime. Our results provide the foundation for a versatile approach for achieving scalable, integrated hybrid systems based on low-loss plasmonic nanoparticle arrays and 2D materials.

Highly sensitive MicroRNA 146a detection using a gold nanoparticle-based CTG repeat probing system and isothermal amplification.

PubMed

Le, Binh Huy; Seo, Young Jun

2018-01-25

We have developed a gold nanoparticle (AuNP)-based CTG repeat probing system displaying high quenching capability and combined it with isothermal amplification for the detection of miRNA 146a. This method of using a AuNP-based CTG repeat probing system with isothermal amplification allowed the highly sensitive (14 aM) and selective detection of miRNA 146a. A AuNP-based CTG repeat probing system having a hairpin structure and a dT F fluorophore exhibited highly efficient quenching because the CTG repeat-based stable hairpin structure imposed a close distance between the AuNP and the dT F residue. A small amount of miRNA 146a induced multiple copies of the CAG repeat sequence during rolling circle amplification; the AuNP-based CTG repeat probing system then bound to the complementary multiple-copy CAG repeat sequence, thereby inducing a structural change from a hairpin to a linear structure with amplified fluorescence. This AuNP-based CTG probing system combined with isothermal amplification could also discriminate target miRNA 146a from one- and two-base-mismatched miRNAs (ORN 1 and ORN 2, respectively). This simple AuNP-based CTG probing system, combined with isothermal amplification to induce a highly sensitive change in fluorescence, allows the detection of miRNA 146a with high sensitivity (14 aM) and selectivity. Copyright © 2017 Elsevier B.V. All rights reserved.

Giant Polarization and High Temperature Monoclinic Phase in a Lead-Free Perovskite of Bi(Zn 0.5Ti 0.5)O 3-BiFeO 3

DOE PAGES

Pan, Zhao; Chen, Jun; Yu, Runze; ...

2016-09-15

Lead-free piezoelectrics have attracted increasing attention due to the awareness of lead toxicity to the environment. Here, a new Bi-based lead-free perovskite of (1-x)Bi(Zn 0.5Ti 0.5)O 3-xBiFeO 3 has been synthesized via high-pressure and high-temperature method. It exhibits interest-ing properties of giant polarization, morphotropic phase boundary (MPB), and monoclinic phase. In particular, large tetragonality ( c/a = 1.228) and giant spontaneous polariza-tion of 110 μC/cm 2 has been obtained in 0.6Bi(Zn 0.5Ti 0.5)O 3-0.4BiFeO 3, which is much higher than most available lead-free materials and conventional Pb(Zr,Ti)O 3. MPB is clearly identified to be constituted by tetragonal and monoclinic phasesmore » at x = 0.5. Notably, a single monoclinic phase has been observed at x = 0.6, which exhibits an intriguing high temperature property. In conclusion, the present results are helpful to explore new lead-free MPB systems in bismuth-based compounds.« less

Ultrathin nickel hydroxide on carbon coated 3D-porous copper structures for high performance supercapacitors.

PubMed

Kang, Kyeong-Nam; Kim, Ik-Hee; Ramadoss, Ananthakumar; Kim, Sun-I; Yoon, Jong-Chul; Jang, Ji-Hyun

2018-01-03

An ultrathin nickel hydroxide layer electrodeposited on a carbon-coated three-dimensional porous copper structure (3D-C/Cu) is suggested as an additive and binder-free conductive electrode with short electron path distances, large electrochemical active sites, and improved structural stability, for high performance supercapacitors. The 3D-porous copper structure (3D-Cu) provides high electrical conductivity and facilitates electron transport between the Ni(OH) 2 active materials and the current collector of the Ni-plate. A carbon coating was applied to the 3D-Cu to prevent the oxidation of Cu, without degrading the electron transport behavior of the 3D-Cu. The 3D-Ni(OH) 2 /C/Cu exhibited a high specific capacitance of 1860 F g -1 at 1 A g -1 , and good cycling performance, with an 86.5% capacitance retention after 10 000 cycles. When tested in a two-electrode system, an asymmetric supercapacitor exhibited an energy density of 147.9 W h kg -1 and a power density of 37.0 kW kg -1 . These results open a new area of ultrahigh-performance supercapacitors, supported by 3D-Cu electrodes.

Effect of surface microstructure on electrochemical performance of garnet solid electrolytes.

PubMed

Cheng, Lei; Chen, Wei; Kunz, Martin; Persson, Kristin; Tamura, Nobumichi; Chen, Guoying; Doeff, Marca

2015-01-28

Cubic garnet phases based on Al-substituted Li7La3Zr2O12 (LLZO) have high ionic conductivities and exhibit good stability versus metallic lithium, making them of particular interest for use in next-generation rechargeable battery systems. However, high interfacial impedances have precluded their successful utilization in such devices until the present. Careful engineering of the surface microstructure, especially the grain boundaries, is critical to achieving low interfacial resistances and enabling long-term stable cycling with lithium metal. This study presents the fabrication of LLZO heterostructured solid electrolytes, which allowed direct correlation of surface microstructure with the electrochemical characteristics of the interface. Grain orientations and grain boundary distributions of samples with differing microstructures were mapped using high-resolution synchrotron polychromatic X-ray Laue microdiffraction. The electrochemical characteristics are strongly dependent upon surface microstructure, with small grained samples exhibiting much lower interfacial resistances and better cycling behavior than those with larger grain sizes. Low area specific resistances of 37 Ω cm(2) were achieved; low enough to ensure stable cycling with minimal polarization losses, thus removing a significant obstacle toward practical implementation of solid electrolytes in high energy density batteries.

Columnar alterations of NADH fluorescence during hypoxia-ischemia in immature rat brain.

PubMed

Welsh, F A; Vannucci, R C; Brierley, J B

1982-01-01

Cerebral hypoxia-ischemia was produced in 7-day postnatal rats by unilateral carotid artery ligation combined with systemic hypoxia (8% O2). Levels of high energy phosphates, which were only slightly altered in the contralateral hemisphere, were nearly depleted in the ipsilateral hemisphere during the 3-h hypoxic insult. With hypoxia of between 1 and 3 hours' duration, columnar alterations of cortical NADH fluorescence occurred in the same location and regional pattern as did histologic damage demonstrated previously (Rice et al., 1981). In regions exhibiting columns of NADH fluorescence, there was no evidence of a columnar reduction of high energy phosphates as levels of ATP and phosphocreatine were nearly zero. Recovery from 3 h of hypoxia was accompanied by partial and regionally heterogeneous restoration of ATP within the ipsilateral hemisphere. Columnar variations of NADH fluorescence were not detected in the recovery period; rather, regions with impaired restitution of high energy phosphates exhibited NADH fluorescence that was diminished diffusely compared to the contralateral hemisphere. The correlation between depressed NADH fluorescence and depleted ATP, present as cortical columns during hypoxia and as larger regions during recovery, suggests that decreased formation of NADH may be limiting the resynthesis of high energy phosphates.

“Turn-On” Protein Fluorescence: In Situ Formation of Cyanine Dyes

PubMed Central

2015-01-01

Protein reengineering of cellular retinoic acid binding protein II (CRABPII) has yielded a genetically addressable system, capable of binding a profluorophoric chromophore that results in fluorescent protein/chromophore complexes. These complexes exhibit far-red emission, with high quantum efficiencies and brightness and also exhibit excellent pH stability spanning the range of 2–11. In the course of this study, it became evident that single mutations of L121E and R59W were most effective in improving the fluorescent characteristics of CRABPII mutants as well as the kinetics of complex formation. The readily crystallizable nature of these proteins was invaluable to provide clues for the observed spectroscopic behavior that results from single mutation of key residues. PMID:25534273

Magnetic and dielectric studies on half-doped orthochromite R(Fe0.5Cr0.5)O3 (R=Gd, Sm) ceramics

NASA Astrophysics Data System (ADS)

Tirupathi, Patri; Reddy, H. Satish Kumar

2018-05-01

In the present paper, we report a details on magnetic and dielectric studies on ball milled single phase Gd(Fe0.5Cr0.5)O3 (GFC) and Sm(Fe0.5Cr0.5)O3 (SmFC) ceramics. The room temperature X-ray diffraction suggest that GFC and SmFC are exhibit orthorhombic crystal system with Pnma space group. Temperature dependent dc-magnetic studies exhibit a complex sequence of magnetic transitions (TN = 281 K) for GFC (TN = 249 K for SmFC ceramics respectively. A weak ferromagnetic character at low temperature were observed for both compounds. In addition, high temperature dielectric studies were also reported for SmFC ceramics.

"Turn-on" protein fluorescence: in situ formation of cyanine dyes.

PubMed

Yapici, Ipek; Lee, Kin Sing Stephen; Berbasova, Tetyana; Nosrati, Meisam; Jia, Xiaofei; Vasileiou, Chrysoula; Wang, Wenjing; Santos, Elizabeth M; Geiger, James H; Borhan, Babak

2015-01-28

Protein reengineering of cellular retinoic acid binding protein II (CRABPII) has yielded a genetically addressable system, capable of binding a profluorophoric chromophore that results in fluorescent protein/chromophore complexes. These complexes exhibit far-red emission, with high quantum efficiencies and brightness and also exhibit excellent pH stability spanning the range of 2-11. In the course of this study, it became evident that single mutations of L121E and R59W were most effective in improving the fluorescent characteristics of CRABPII mutants as well as the kinetics of complex formation. The readily crystallizable nature of these proteins was invaluable to provide clues for the observed spectroscopic behavior that results from single mutation of key residues.

Full reinforcement operators in aggregation techniques.

PubMed

Yager, R R; Rybalov, A

1998-01-01

We introduce the concept of upward reinforcement in aggregation as one in which a collection of high scores can reinforce or corroborate each other to give an even higher score than any of the individual arguments. The concept of downward reinforcement is also introduced as one in which low scores reinforce each other. Our concern is with full reinforcement aggregation operators, those exhibiting both upward and downward reinforcement. It is shown that the t-norm and t-conorm operators are not full reinforcement operators. A class of operators called fixed identity MICA operators are shown to exhibit the property of full reinforcement. We present some families of these operators. We use the fuzzy system modeling technique to provide further examples of these operators.

“Turn-On” Protein Fluorescence: In Situ Formation of Cyanine Dyes

DOE PAGES

Yapici, Ipek; Lee, Kin Sing Stephen; Berbasova, Tetyana; ...

2014-12-22

Protein reengineering of cellular retinoic acid binding protein II (CRABPII) has yielded a genetically addressable system, capable of binding a profluorophoric chromophore that results in fluorescent protein/chromophore complexes. These complexes exhibit far-red emission, with high quantum efficiencies and brightness and also exhibit excellent pH stability spanning the range of 2$-$11. In the course of this study, it became evident that single mutations of L121E and R59W were most effective in improving the fluorescent characteristics of CRABPII mutants as well as the kinetics of complex formation. The readily crystallizable nature of these proteins was invaluable to provide clues for the observedmore » spectroscopic behavior that results from single mutation of key residues.« less

Transparent ceramic photo-optical semiconductor high power switches

DOEpatents

Werne, Roger W.; Sullivan, James S.; Landingham, Richard L.

2016-01-19

A photoconductive semiconductor switch according to one embodiment includes a structure of sintered nanoparticles of a high band gap material exhibiting a lower electrical resistance when excited by light relative to an electrical resistance thereof when not exposed to the light. A method according to one embodiment includes creating a mixture comprising particles, at least one dopant, and at least one solvent; adding the mixture to a mold; forming a green structure in the mold; and sintering the green structure to form a transparent ceramic. Additional system, methods and products are also presented.

Optical air-coupled NDT system with ultra-broad frequency bandwidth (Conference Presentation)

NASA Astrophysics Data System (ADS)

Fischer, Balthasar; Rohringer, Wolfgang; Heine, Thomas

2017-05-01

We present a novel, optical ultrasound airborne acoustic testing setup exhibiting a frequency bandwidth of 1MHz in air. The sound waves are detected by a miniaturized Fabry-Pérot interferometer (2mm cavity) whilst the sender consists of a thermoacoustic emitter or a short laser pulse We discuss characterization measurements and C-scans of a selected set of samples, including Carbon fiber reinforced polymer (CFRP). The high detector sensitivity allows for an increased penetration depth. The high frequency and the small transducer dimensions lead to a compelling image resolution.

Partially Filled Aperture Interferometric Telescopes: Achieving Large Aperture and Coronagraphic Performance

NASA Astrophysics Data System (ADS)

Moretto, G.; Kuhn, J.; Langlois, M.; Berdugyna, S.; Tallon, M.

2017-09-01

Telescopes larger than currently planned 30-m class instruments must break the mass-aperture scaling relationship of the Keck-generation of multi-segmented telescopes. Partially filled aperture, but highly redundant baseline interferometric instruments may achieve both large aperture and high dynamic range. The PLANETS FOUNDATION group has explored hybrid telescope-interferometer concepts for narrow-field optical systems that exhibit coronagraphic performance over narrow fields-of-view. This paper describes how the Colossus and Exo-Life Finder telescope designs achieve 10x lower moving masses than current Extremely Large Telescopes.

High spatial resolution distributed optical fiber dynamic strain sensor with enhanced frequency and strain resolution.

PubMed

Masoudi, Ali; Newson, Trevor P

2017-01-15

A distributed optical fiber dynamic strain sensor with high spatial and frequency resolution is demonstrated. The sensor, which uses the ϕ-OTDR interrogation technique, exhibited a higher sensitivity thanks to an improved optical arrangement and a new signal processing procedure. The proposed sensing system is capable of fully quantifying multiple dynamic perturbations along a 5 km long sensing fiber with a frequency and spatial resolution of 5 Hz and 50 cm, respectively. The strain resolution of the sensor was measured to be 40 nε.

[Advances of tumor targeting peptides drug delivery system with pH-sensitive activities].

PubMed

Ma, Yin-yun; Li, Li; Huang, Hai-feng; Gou, San-hu; Ni, Jing-man

2016-05-01

The pH-sensitive peptides drug delivery systems, which target to acidic extracellular environment of tumor tissue, have many advantages in drug delivery. They exhibit a high specificity to tumor and low cytotoxicity, which significantly increase the efficacy of traditional anti-cancer drugs. In recent years the systems have received a great attention. The pH-sensitive peptides drug delivery systems can be divided into five types according to the difference in pH-responsive mechanism,type of peptides and carrier materials. This paper summarizes the recent progresses in the field with a focus on the five types of pH-sensitive peptides in drug delivery systems. This may provide a guideline to design and application of tumor targeting drugs.

L1 Adaptive Control Augmentation System with Application to the X-29 Lateral/Directional Dynamics: A Multi-Input Multi-Output Approach

NASA Technical Reports Server (NTRS)

Griffin, Brian Joseph; Burken, John J.; Xargay, Enric

2010-01-01

This paper presents an L(sub 1) adaptive control augmentation system design for multi-input multi-output nonlinear systems in the presence of unmatched uncertainties which may exhibit significant cross-coupling effects. A piecewise continuous adaptive law is adopted and extended for applicability to multi-input multi-output systems that explicitly compensates for dynamic cross-coupling. In addition, explicit use of high-fidelity actuator models are added to the L1 architecture to reduce uncertainties in the system. The L(sub 1) multi-input multi-output adaptive control architecture is applied to the X-29 lateral/directional dynamics and results are evaluated against a similar single-input single-output design approach.

Logarithmic entanglement lightcone in many-body localized systems

NASA Astrophysics Data System (ADS)

Deng, Dong-Ling; Li, Xiaopeng; Pixley, J. H.; Wu, Yang-Le; Das Sarma, S.

2017-01-01

We theoretically study the response of a many-body localized system to a local quench from a quantum information perspective. We find that the local quench triggers entanglement growth throughout the whole system, giving rise to a logarithmic lightcone. This saturates the modified Lieb-Robinson bound for quantum information propagation in many-body localized systems previously conjectured based on the existence of local integrals of motion. In addition, near the localization-delocalization transition, we find that the final states after the local quench exhibit volume-law entanglement. We also show that the local quench induces a deterministic orthogonality catastrophe for highly excited eigenstates, where the typical wave-function overlap between the pre- and postquench eigenstates decays exponentially with the system size.

On the torque and wear behavior of selected thin film MOS2 lubricated gimbal bearings

NASA Technical Reports Server (NTRS)

Bohner, John J.; Conley, Peter L.

1988-01-01

During the thermal vacuum test phase of the GOES 7 spacecraft, the primary scan mirror system exhibited unacceptably high drive friction. The observed friction was found to correlate with small misalignments in the mirror structure and unavoidable loads induced by the vehicle spin. An intensive effort to understand and document the performance of the scan mirror bearing system under these loads is described. This effort involved calculation of the bearing loads and expected friction torque, comparison of the computed values to test data, and verification of the lubrication system performance and limitations under external loads. The study culminated in a successful system launch in February of 1987. The system has operated as predicted since that time.

Liquid Crystalline Behavior and Related Properties of Colloidal Systems of Inorganic Oxide Nanosheets

PubMed Central

Nakato, Teruyuki; Miyamoto, Nobuyoshi

2009-01-01

Inorganic layered crystals exemplified by clay minerals can be exfoliated in solvents to form colloidal dispersions of extremely thin inorganic layers that are called nanosheets. The obtained “nanosheet colloids” form lyotropic liquid crystals because of the highly anisotropic shape of the nanosheets. This system is a rare example of liquid crystals consisting of inorganic crystalline mesogens. Nanosheet colloids of photocatalytically active semiconducting oxides can exhibit unusual photoresponses that are not observed for organic liquid crystals. This review summarizes experimental work on the phase behavior of the nanosheet colloids as well as photochemical reactions observed in the clay and semiconducting nanosheets system.

Graphene based strain sensor with LCP substrate

NASA Astrophysics Data System (ADS)

Nie, M.; Yang, H. S.; Xia, Y. H.

2018-02-01

A flexible strain sensor constructed by an efficient, low-cost fabrication strategy is presented in this paper. It is assembled by adhering grid-like graphene on LCP substrate. Kinds of measurement setup have been designed to verify that the proposed flexible sensor device is suitable to be used in health monitoring system. From the experiment results, it can be proved that the sensor exhibits the following features: ultra-light, relatively good sensitivity, high reversibility, superior physical robustness, easy fabrication. With the great performance of this flexible strain sensor, it is considered to play an important role in body monitoring, structural health monitoring system, fatigue detection and healthcare systems in the near future.

Design and field results of a walk-through EDS

NASA Astrophysics Data System (ADS)

Wendel, Gregory J.; Bromberg, Edward E.; Durfee, Memorie K.; Curby, William A.

1997-01-01

A walk-through portal sampling module which incorporates active sampling has been developed. The module uses opposing wands which actively brush the subjects exterior clothing to disturb explosive traces. These traces are entrained in an air stream and transported to a High Speed GC- chemiluminescence explosives detection system. This combination provides automatic screening of passengers at rates of 10 per minute. The system exhibits sensitivity and selectivity which equals or betters that available from commercially available manual equipment. The systems has been developed for deployment at border crossings, airports and other security screening points. Detailed results of laboratory tests and airport field trials are reviewed.

NLOphoric multichromophoric auxiliary methoxy aided triphenylamine D-π-A chromophores - Spectroscopic and computational studies

NASA Astrophysics Data System (ADS)

Erande, Yogesh; Kothavale, Shantaram; Sreenath, Mavila C.; Chitrambalam, Subramaniyan; Joe, Isaac H.; Sekar, Nagaiyan

2017-11-01

Molecules containing methoxy supported triphenylamine as strong electron-donor and dicyanovinyl as electron-acceptor groups interacting via isophorone as a configurationally locked polyene π-conjugated bridge are studied for their nonlinear optical properties. The photophysical study of examined chromophores in non-polar and polar solvents suggest that they exhibit strong emission solvatochromism and significant charge transfer characteristics supported by Lippert-Mataga plots and Generalised Mulliken Hush analysis. Linear and nonlinear optical properties as well as electronic properties measured by spectroscopic methods and cyclic voltametry and supported by DFT calculation were used to elucidate the structure property relationships. All three chromophores exhibit very high thermal stabilities with the decomposition temperatures higher than 340°C. The vibrational motions play very important role in determining the overall NLO response styryl chromophores which was established by DFT study. Dye 3 with maximum nonlinear optical susceptibility among three D-π-A systems proves that the multibranched push-pull chromophores exhibit a higher third order nonlinear susceptibility and justifies the design strategy.

Dynamical gauge effects in an open quantum network

NASA Astrophysics Data System (ADS)

Zhao, Jianshi; Price, Craig; Liu, Qi; Gemelke, Nathan

2016-05-01

We describe new experimental techniques for simulation of high-energy field theories based on an analogy between open thermodynamic systems and effective dynamical gauge-fields following SU(2) × U(1) Yang-Mills models. By coupling near-resonant laser-modes to atoms moving in a disordered optical environment, we create an open system which exhibits a non-equilibrium phase transition between two steady-state behaviors, exhibiting scale-invariant behavior near the transition. By measuring transport of atoms through the disordered network, we observe two distinct scaling behaviors, corresponding to the classical and quantum limits for the dynamical gauge field. This behavior is loosely analogous to dynamical gauge effects in quantum chromodynamics, and can mapped onto generalized open problems in theoretical understanding of quantized non-Abelian gauge theories. Additional, the scaling behavior can be understood from the geometric structure of the gauge potential and linked to the measure of information in the local disordered potential, reflecting an underlying holographic principle. We acknowledge support from NSF Award No.1068570, and the Charles E. Kaufman Foundation.

Atomistic study of the solid state inside graphene nanobubbles.

PubMed

Iakovlev, Evgeny; Zhilyaev, Petr; Akhatov, Iskander

2017-12-20

A two-dimensional (2D) material placed on an atomically flat substrate can lead to the formation of surface nanobubbles trapping different types of substances. In this paper graphene nanobubbles of the radius of 7-34 nm with argon atoms inside are studied using molecular dynamics (MD). All modeled graphene nanobubbles except for the smallest ones exhibit an universal shape, i.e., a constant ratio of a bubble height to its footprint radius, which is in an agreement with experimental studies and their interpretation using the elastic theory of membranes. MD simulations reveal that argon does exist in a solid close-packed phase, although the internal pressure in the nanobubble is not sufficiently high for the ordinary crystallization that would occur in a bulk system. The smallest graphene bubbles with a radius of 7 nm exhibit an unusual "pancake" shape. Previously, nanobubbles with a similar pancake shape were experimentally observed in completely different systems at the interface between water and a hydrophobic surface.

Magnetic properties of doped Mn-Ga alloys made by mechanical milling and heat treatment

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

Brown, Daniel R.; National High Magnetic Field Laboratory, Tallahassee, FL 32310; Han, Ke

2016-05-15

Mn-Ga alloys have shown hard magnetic properties, even though these alloys contain no rare-earth metals. However, much work is needed before rare-earth magnets can be replaced. We have examined the magnetic properties of bulk alloys made with partial replacement of both the Mn and Ga elements in the Mn{sub 0.8}Ga{sub 0.2} system. Bulk samples of Mn-Ga-Bi, Mn-Ga-Al, Mn-Fe-Ga and Mn-(FeB)-Ga alloys were fabricated and studied using mechanically milling and heat treatments while altering the atomic percentage of the third element between 2.5 and 20 at%. The ternary alloy exhibits all hard magnetic properties at room temperature with large coercivity. Annealedmore » Mn-Ga-X bulk composites exhibit high coercivities up to 16.6 kOe and remanence up to 9.8 emu/g, that is increased by 115% over the binary system.« less

The Effect of Pluronic 123 Surfactant concentration on The N2 Adsorption Capacity of Mesoporous Silica SBA-15: Dubinin-Astakhov Adsorption Isotherm Analysis

NASA Astrophysics Data System (ADS)

Dhaneswara, Donanta; Siti Agustina, A. A. A.; Dewantoro Adhy, P.; Delayori, Farhan; Fajar Fatriansyah, Jaka

2018-04-01

Mesoporous SBA-15 has been successfully synthesized at various concentration of Pluronic 123 surfactant (7mM, 50 mM, 54 mM, 60 mM and 66 mM) and the effect of these various concentrations on the N2 adsorption capacity has been investigated. The adsorption analysis was conducted using Dubinin-Astakhov isotherm model for multilayer adsorption phenomenon. It was found that etryat low concentration of Pluronic 123, the system exhibits type I adsorption isotherm while at high concentration, the system exhibits type IV adsorption with H1 hysteresis curve which indicates the existence of pores with cylindrical geometry, relatively uniform pore size and possibility of pore network effects. It also was found that, by using D-A isotherm model fitting, at 60 mM concentration of Pluronic 123, SBA-15 has the highest adsorption capacity which stands at 421 cm3/gram.

Acceptance threshold hypothesis is supported by chemical similarity of cuticular hydrocarbons in a stingless bee, Melipona asilvai.

PubMed

Nascimento, D L; Nascimento, F S

2012-11-01

The ability to discriminate nestmates from non-nestmates in insect societies is essential to protect colonies from conspecific invaders. The acceptance threshold hypothesis predicts that organisms whose recognition systems classify recipients without errors should optimize the balance between acceptance and rejection. In this process, cuticular hydrocarbons play an important role as cues of recognition in social insects. The aims of this study were to determine whether guards exhibit a restrictive level of rejection towards chemically distinct individuals, becoming more permissive during the encounters with either nestmate or non-nestmate individuals bearing chemically similar profiles. The study demonstrates that Melipona asilvai (Hymenoptera: Apidae: Meliponini) guards exhibit a flexible system of nestmate recognition according to the degree of chemical similarity between the incoming forager and its own cuticular hydrocarbons profile. Guards became less restrictive in their acceptance rates when they encounter non-nestmates with highly similar chemical profiles, which they probably mistake for nestmates, hence broadening their acceptance level.

Overcoming the crystallization and designability issues in the ultrastable zirconium phosphonate framework system

DOE PAGES

Zheng, Tao; Yang, Zaixing; Gui, Daxiang; ...

2017-05-30

Metal-organic frameworks (MOFs) based on zirconium phosphonates exhibit superior chemical stability suitable for applications under harsh conditions. These compounds mostly exist as poorly crystallized precipitates, and precise structural information has therefore remained elusive. Furthermore, a zero-dimensional zirconium phosphonate cluster acting as secondary building unit has been lacking, leading to poor designability in this system. We overcome these challenges and obtain single crystals of three zirconium phosphonates that are suitable for structural analysis. Furthermore, these compounds are built by previously unknown isolated zirconium phosphonate clusters and exhibit combined high porosity and ultrastability even in fuming acids. SZ-2 possesses the largest voidmore » volume recorded in zirconium phosphonates and SZ-3 represents the most porous crystalline zirconium phosphonate and the only porous MOF material reported to survive in aqua regia. SZ-2 and SZ-3 can effectively remove uranyl ions from aqueous solutions over a wide pH range, and we have elucidated the removal mechanism.« less

Expression-Linked Patterns of Codon Usage, Amino Acid Frequency, and Protein Length in the Basally Branching Arthropod Parasteatoda tepidariorum

PubMed Central

Whittle, Carrie A.; Extavour, Cassandra G.

2016-01-01

Abstract Spiders belong to the Chelicerata, the most basally branching arthropod subphylum. The common house spider, Parasteatoda tepidariorum, is an emerging model and provides a valuable system to address key questions in molecular evolution in an arthropod system that is distinct from traditionally studied insects. Here, we provide evidence suggesting that codon usage, amino acid frequency, and protein lengths are each influenced by expression-mediated selection in P. tepidariorum. First, highly expressed genes exhibited preferential usage of T3 codons in this spider, suggestive of selection. Second, genes with elevated transcription favored amino acids with low or intermediate size/complexity (S/C) scores (glycine and alanine) and disfavored those with large S/C scores (such as cysteine), consistent with the minimization of biosynthesis costs of abundant proteins. Third, we observed a negative correlation between expression level and coding sequence length. Together, we conclude that protein-coding genes exhibit signals of expression-related selection in this emerging, noninsect, arthropod model. PMID:27017527

Overcoming the crystallization and designability issues in the ultrastable zirconium phosphonate framework system

PubMed Central

Zheng, Tao; Yang, Zaixing; Gui, Daxiang; Liu, Zhiyong; Wang, Xiangxiang; Dai, Xing; Liu, Shengtang; Zhang, Linjuan; Gao, Yang; Chen, Lanhua; Sheng, Daopeng; Wang, Yanlong; Diwu, Juan; Wang, Jianqiang; Zhou, Ruhong; Chai, Zhifang; Albrecht-Schmitt, Thomas E.; Wang, Shuao

2017-01-01

Metal-organic frameworks (MOFs) based on zirconium phosphonates exhibit superior chemical stability suitable for applications under harsh conditions. These compounds mostly exist as poorly crystallized precipitates, and precise structural information has therefore remained elusive. Furthermore, a zero-dimensional zirconium phosphonate cluster acting as secondary building unit has been lacking, leading to poor designability in this system. Herein, we overcome these challenges and obtain single crystals of three zirconium phosphonates that are suitable for structural analysis. These compounds are built by previously unknown isolated zirconium phosphonate clusters and exhibit combined high porosity and ultrastability even in fuming acids. SZ-2 possesses the largest void volume recorded in zirconium phosphonates and SZ-3 represents the most porous crystalline zirconium phosphonate and the only porous MOF material reported to survive in aqua regia. SZ-2 and SZ-3 can effectively remove uranyl ions from aqueous solutions over a wide pH range, and we have elucidated the removal mechanism. PMID:28555656

Overcoming the crystallization and designability issues in the ultrastable zirconium phosphonate framework system

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

Zheng, Tao; Yang, Zaixing; Gui, Daxiang

Metal-organic frameworks (MOFs) based on zirconium phosphonates exhibit superior chemical stability suitable for applications under harsh conditions. These compounds mostly exist as poorly crystallized precipitates, and precise structural information has therefore remained elusive. Furthermore, a zero-dimensional zirconium phosphonate cluster acting as secondary building unit has been lacking, leading to poor designability in this system. We overcome these challenges and obtain single crystals of three zirconium phosphonates that are suitable for structural analysis. Furthermore, these compounds are built by previously unknown isolated zirconium phosphonate clusters and exhibit combined high porosity and ultrastability even in fuming acids. SZ-2 possesses the largest voidmore » volume recorded in zirconium phosphonates and SZ-3 represents the most porous crystalline zirconium phosphonate and the only porous MOF material reported to survive in aqua regia. SZ-2 and SZ-3 can effectively remove uranyl ions from aqueous solutions over a wide pH range, and we have elucidated the removal mechanism.« less

De-vitrification of nanoscale phase-separated amorphous thin films in the immiscible copper-niobium system

NASA Astrophysics Data System (ADS)

Puthucode, A.; Devaraj, A.; Nag, S.; Bose, S.; Ayyub, P.; Kaufman, M. J.; Banerjee, R.

2014-05-01

Copper and niobium are mutually immiscible in the solid state and exhibit a large positive enthalpy of mixing in the liquid state. Using vapour quenching via magnetron co-sputter deposition, far-from equilibrium amorphous Cu-Nb films have been deposited which exhibit a nanoscale phase separation. Annealing these amorphous films at low temperatures (~200 °C) initiates crystallization via the nucleation and growth of primary nanocrystals of a face-centred cubic Cu-rich phase separated by the amorphous matrix. Interestingly, subsequent annealing at a higher temperature (>300 °C) leads to the polymorphic nucleation and growth of large spherulitic grains of a body-centred cubic Nb-rich phase within the retained amorphous matrix of the partially crystallized film. This sequential two-stage crystallization process has been investigated in detail by combining transmission electron microscopy [TEM] (including high-resolution TEM) and atom probe tomography studies. These results provide new insights into the crystallization behaviour of such unusual far-from equilibrium phase-separated metallic glasses in immiscible systems.

Identifying bubble collapse in a hydrothermal system using hidden Markov models

USGS Publications Warehouse

Dawson, P.B.; Benitez, M.C.; Lowenstern, J. B.; Chouet, B.A.

2012-01-01

Beginning in July 2003 and lasting through September 2003, the Norris Geyser Basin in Yellowstone National Park exhibited an unusual increase in ground temperature and hydrothermal activity. Using hidden Markov model theory, we identify over five million high-frequency (>15Hz) seismic events observed at a temporary seismic station deployed in the basin in response to the increase in hydrothermal activity. The source of these seismic events is constrained to within ???100 m of the station, and produced ???3500-5500 events per hour with mean durations of ???0.35-0.45s. The seismic event rate, air temperature, hydrologic temperatures, and surficial water flow of the geyser basin exhibited a marked diurnal pattern that was closely associated with solar thermal radiance. We interpret the source of the seismicity to be due to the collapse of small steam bubbles in the hydrothermal system, with the rate of collapse being controlled by surficial temperatures and daytime evaporation rates. copyright 2012 by the American Geophysical Union.

Identifying bubble collapse in a hydrothermal system using hiddden Markov models

USGS Publications Warehouse

Dawson, Phillip B.; Benitez, M.C.; Lowenstern, Jacob B.; Chouet, Bernard A.

2012-01-01

Beginning in July 2003 and lasting through September 2003, the Norris Geyser Basin in Yellowstone National Park exhibited an unusual increase in ground temperature and hydrothermal activity. Using hidden Markov model theory, we identify over five million high-frequency (>15 Hz) seismic events observed at a temporary seismic station deployed in the basin in response to the increase in hydrothermal activity. The source of these seismic events is constrained to within ~100 m of the station, and produced ~3500–5500 events per hour with mean durations of ~0.35–0.45 s. The seismic event rate, air temperature, hydrologic temperatures, and surficial water flow of the geyser basin exhibited a marked diurnal pattern that was closely associated with solar thermal radiance. We interpret the source of the seismicity to be due to the collapse of small steam bubbles in the hydrothermal system, with the rate of collapse being controlled by surficial temperatures and daytime evaporation rates.

Rapid feedback of chemical vapor deposition growth mechanisms by operando X-ray diffraction

DOE PAGES

Martin, Aiden A.; Depond, Philip J.; Bagge-Hansen, Michael; ...

2018-03-14

An operando x-ray diffraction system is presented for elucidating optimal laser assisted chemical vapor deposition growth conditions. The technique is utilized to investigate deposition dynamics of boron-carbon materials using trimethyl borate precursor. Trimethyl borate exhibits vastly reduced toxicological and flammability hazards compared to existing precursors, but has previously not been applied to boron carbide growth. Crystalline boron-rich carbide material is produced in a narrow growth regime on addition of hydrogen during the growth phase at high temperature. Finally, the use of the operando x-ray diffraction system allows for the exploration of highly nonequilibrium conditions and rapid process control, which aremore » not possible using ex situ diagnostics.« less

Rapid feedback of chemical vapor deposition growth mechanisms by operando X-ray diffraction

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

Martin, Aiden A.; Depond, Philip J.; Bagge-Hansen, Michael

An operando x-ray diffraction system is presented for elucidating optimal laser assisted chemical vapor deposition growth conditions. The technique is utilized to investigate deposition dynamics of boron-carbon materials using trimethyl borate precursor. Trimethyl borate exhibits vastly reduced toxicological and flammability hazards compared to existing precursors, but has previously not been applied to boron carbide growth. Crystalline boron-rich carbide material is produced in a narrow growth regime on addition of hydrogen during the growth phase at high temperature. Finally, the use of the operando x-ray diffraction system allows for the exploration of highly nonequilibrium conditions and rapid process control, which aremore » not possible using ex situ diagnostics.« less

Single-site trinuclear copper oxygen clusters in mordenite for selective conversion of methane to methanol

DOE PAGES

Grundner, Sebastian; Markovits, Monica A. C.; Li, Guanna; ...

2015-06-25

Copper-exchanged zeolites with mordenite structure mimic the nuclearity and reactivity of active sites in particulate methane monooxygenase, which are enzymes able to selectively oxidize methane to methanol. Here we show that the mordenite micropores provide a perfect confined environment for the highly selective stabilization of trinuclear copper-oxo clusters that exhibit a high reactivity towards activation of carbon–hydrogen bonds in methane and its subsequent transformation to methanol. In conclusion, the similarity with the enzymatic systems is also implied from the similarity of the reversible rearrangements of the trinuclear clusters occurring during the selective transformations of methane along the reaction path towardsmore » methanol, in both the enzyme system and copper-exchanged mordenite.« less

Single-site trinuclear copper oxygen clusters in mordenite for selective conversion of methane to methanol

PubMed Central

Grundner, Sebastian; Markovits, Monica A.C.; Li, Guanna; Tromp, Moniek; Pidko, Evgeny A.; Hensen, Emiel J.M.; Jentys, Andreas; Sanchez-Sanchez, Maricruz; Lercher, Johannes A.

2015-01-01

Copper-exchanged zeolites with mordenite structure mimic the nuclearity and reactivity of active sites in particulate methane monooxygenase, which are enzymes able to selectively oxidize methane to methanol. Here we show that the mordenite micropores provide a perfect confined environment for the highly selective stabilization of trinuclear copper-oxo clusters that exhibit a high reactivity towards activation of carbon–hydrogen bonds in methane and its subsequent transformation to methanol. The similarity with the enzymatic systems is also implied from the similarity of the reversible rearrangements of the trinuclear clusters occurring during the selective transformations of methane along the reaction path towards methanol, in both the enzyme system and copper-exchanged mordenite. PMID:26109507

Accelerating fissile material detection with a neutron source

DOEpatents

Rowland, Mark S.; Snyderman, Neal J.

2018-01-30

A neutron detector system for discriminating fissile material from non-fissile material wherein a digital data acquisition unit collects data at high rate, and in real-time processes large volumes of data directly to count neutrons from the unknown source and detecting excess grouped neutrons to identify fission in the unknown source. The system includes a Poisson neutron generator for in-beam interrogation of a possible fissile neutron source and a DC power supply that exhibits electrical ripple on the order of less than one part per million. Certain voltage multiplier circuits, such as Cockroft-Walton voltage multipliers, are used to enhance the effective of series resistor-inductor circuits components to reduce the ripple associated with traditional AC rectified, high voltage DC power supplies.

Dynamic characteristic investigation on the fuel pressure of diesel engines electronic in-line pump system

NASA Astrophysics Data System (ADS)

Liu, You; Yuan, Zhi-Guo; Fan, Li-Yun; Tian, Bin-Qi

2010-12-01

The electronic in-line pump (EIP) is a complex system consisting of mechanical, hydraulic, and electromagnetic parts. Experimental study showed that the fuel pressure of the plunger and the fuel drainage of the pressure system after fuel injection could result in fuel pressure fluctuation in the low pressure system. Such fluctuation exhibited pulsating cycle fluctuation as the amplitude rose with the increase of the injection pulse width. The time domain analysis found that the pressure time history curve and injection cylinders corresponded with a one-to-one relationship. By frequency domain analysis, the result was that with the increase of the working cylinder number, the high frequency amplitude gradually increased and the basic frequency amplitude gradually decreased. The conclusion was that through wavelet transformation, the low pressure signal simultaneously moved towards low frequency as the high frequency of the wavelet transformation signal with the working cylinder number increased. Lastly, by using the numerical model, the study investigated the simulation research concerning the relationship of the fluctuation dynamic characteristic in the low pressure system and the fuel injection characteristic of the high pressure system, completing the conclusions obtained by the experimental study.

The activated iron system for phosphorus recovery in aqueous environments.

PubMed

Wan, Jun; Jiang, Xiaoqing; Zhang, Tian C; Hu, Jiong; Richter-Egger, Dana; Feng, Xiaonan; Zhou, Aijiao; Tao, Tao

2018-04-01

Finding a good sorbent for phosphorus (P) recovery from the aquatic environment is critical for preventing eutrophication and providing P resources. The activated iron system (mainly consisted of zero-valent iron (ZVI), Fe 3 O 4 and Fe 2+ ) has been reported to exhibit a favorable performance towards various contaminants in wastewater, but its effect on P recovery has not been studied systematically. In this study, we used Fe 2+ -nitrate pretreatment reaction to prepare the activated iron system and then applied it to P recovery. Results show that more than 99% P was removed from water in 60 min; co-existing anions (NO 3 - , Cl - and SO 4 2- ) and natural organic matter (NOM) had little effect on P removal. The P removal capacity of activated iron system is very high compared with currently reported sorbents. Externally-supplied Fe 2+ plays an important role on P removal in the system. Regeneration study shows that the activated iron system exhibited stable P recovery ability by using 0.1 M NaOH solution. Various methods were applied to characterize the ZVI and iron corrosion, and results conclude that sorption precipitation, and co-precipitation contribute to P removal. This method will be promising and have an application potential in the field for efficient and cost-effective recovery of P with cheap microscale zero valent iron. Copyright © 2017 Elsevier Ltd. All rights reserved.

Atomistic Simulations of Detonation Instabilities in Condensed Phase Systems

NASA Astrophysics Data System (ADS)

Kober, Edward; Heim, Andrew; Germann, Timothy; Jensen, Niels

2007-06-01

We report the results of simulations of condensed phase detonation phenomena using a model diatomic system: 2AB -> A2 + B2. The initial set of parameters for this system corresponded to the Model 0 set of C. White et al, which exhibits a steady, Chapman-Jouget (CJ) detonation structure with a reaction zone length of 30-100 å. This has a highly compressed CJ state (V/V0˜0.5) that does not consist of discrete molecular species. The potential form was modified so that a more molecular CJ state resulted, consistent with the models for conventional organic explosives. The new system has a less dense CJ state (V/V0˜0.8), and the reaction zone was substantially extended. The reaction rate fits Arrhenius-type kinetics with an activation energy of ˜2 eV, with a minor density dependence. In contrast, the original Model 0 system had a lower activation energy (˜1 eV) with a stronger density dependence. The new system exhibits quite marked two dimensional instability structures with well-defined wavelengths similar to what has been observed for gas-phase detonations and for nitromethane. Depending on the exothermicity and the width of the periodic simulations, these instabilities can result in either detonation failure or quasi-steady propagation. The observed propagation velocities are several per cent higher than CJ values derived from thermodynamic analyses.

Multistability and hidden attractors in a relay system with hysteresis

NASA Astrophysics Data System (ADS)

Zhusubaliyev, Zhanybai T.; Mosekilde, Erik; Rubanov, Vasily G.; Nabokov, Roman A.

2015-06-01

For nonlinear dynamic systems with switching control, the concept of a "hidden attractor" naturally applies to a stable dynamic state that either (1) coexists with the stable switching cycle or (2), if the switching cycle is unstable, has a basin of attraction that does not intersect with the neighborhood of that cycle. We show how the equilibrium point of a relay system disappears in a boundary-equilibrium bifurcation as the system enters the region of autonomous switching dynamics and demonstrate experimentally how a relay system can exhibit large amplitude chaotic oscillations at high values of the supply voltage. By investigating a four-dimensional model of the experimental relay system we finally show how a variety of hidden periodic, quasiperiodic and chaotic attractors arise, transform and disappear through different bifurcations.

Shape Modification and Size Classification of Microcrystalline Graphite Powder as Anode Material for Lithium-Ion Batteries

NASA Astrophysics Data System (ADS)

Wang, Cong; Gai, Guosheng; Yang, Yufen

2018-03-01

Natural microcrystalline graphite (MCG) composed of many crystallites is a promising new anode material for lithium-ion batteries (LiBs) and has received considerable attention from researchers. MCG with narrow particle size distribution and high sphericity exhibits excellent electrochemical performance. A nonaddition process to prepare natural MCG as a high-performance LiB anode material is described. First, raw MCG was broken into smaller particles using a pulverization system. Then, the particles were modified into near-spherical shape using a particle shape modification system. Finally, the particle size distribution was narrowed using a centrifugal rotor classification system. The products with uniform hemispherical shape and narrow size distribution had mean particle size of approximately 9 μm, 10 μm, 15 μm, and 20 μm. Additionally, the innovative pilot experimental process increased the product yield of the raw material. Finally, the electrochemical performance of the prepared MCG was tested, revealing high reversible capacity and good cyclability.

Modeling long correlation times using additive binary Markov chains: Applications to wind generation time series.

PubMed

Weber, Juliane; Zachow, Christopher; Witthaut, Dirk

2018-03-01

Wind power generation exhibits a strong temporal variability, which is crucial for system integration in highly renewable power systems. Different methods exist to simulate wind power generation but they often cannot represent the crucial temporal fluctuations properly. We apply the concept of additive binary Markov chains to model a wind generation time series consisting of two states: periods of high and low wind generation. The only input parameter for this model is the empirical autocorrelation function. The two-state model is readily extended to stochastically reproduce the actual generation per period. To evaluate the additive binary Markov chain method, we introduce a coarse model of the electric power system to derive backup and storage needs. We find that the temporal correlations of wind power generation, the backup need as a function of the storage capacity, and the resting time distribution of high and low wind events for different shares of wind generation can be reconstructed.

Modeling long correlation times using additive binary Markov chains: Applications to wind generation time series

NASA Astrophysics Data System (ADS)

Weber, Juliane; Zachow, Christopher; Witthaut, Dirk

2018-03-01

Wind power generation exhibits a strong temporal variability, which is crucial for system integration in highly renewable power systems. Different methods exist to simulate wind power generation but they often cannot represent the crucial temporal fluctuations properly. We apply the concept of additive binary Markov chains to model a wind generation time series consisting of two states: periods of high and low wind generation. The only input parameter for this model is the empirical autocorrelation function. The two-state model is readily extended to stochastically reproduce the actual generation per period. To evaluate the additive binary Markov chain method, we introduce a coarse model of the electric power system to derive backup and storage needs. We find that the temporal correlations of wind power generation, the backup need as a function of the storage capacity, and the resting time distribution of high and low wind events for different shares of wind generation can be reconstructed.

Toward a molecular programming language for algorithmic self-assembly

NASA Astrophysics Data System (ADS)

Patitz, Matthew John

Self-assembly is the process whereby relatively simple components autonomously combine to form more complex objects. Nature exhibits self-assembly to form everything from microscopic crystals to living cells to galaxies. With a desire to both form increasingly sophisticated products and to understand the basic components of living systems, scientists have developed and studied artificial self-assembling systems. One such framework is the Tile Assembly Model introduced by Erik Winfree in 1998. In this model, simple two-dimensional square 'tiles' are designed so that they self-assemble into desired shapes. The work in this thesis consists of a series of results which build toward the future goal of designing an abstracted, high-level programming language for designing the molecular components of self-assembling systems which can perform powerful computations and form into intricate structures. The first two sets of results demonstrate self-assembling systems which perform infinite series of computations that characterize computably enumerable and decidable languages, and exhibit tools for algorithmically generating the necessary sets of tiles. In the next chapter, methods for generating tile sets which self-assemble into complicated shapes, namely a class of discrete self-similar fractal structures, are presented. Next, a software package for graphically designing tile sets, simulating their self-assembly, and debugging designed systems is discussed. Finally, a high-level programming language which abstracts much of the complexity and tedium of designing such systems, while preventing many of the common errors, is presented. The summation of this body of work presents a broad coverage of the spectrum of desired outputs from artificial self-assembling systems and a progression in the sophistication of tools used to design them. By creating a broader and deeper set of modular tools for designing self-assembling systems, we hope to increase the complexity which is attainable. These tools provide a solid foundation for future work in both the Tile Assembly Model and explorations into more advanced models.

Understanding the high-temperature deformation

NASA Astrophysics Data System (ADS)

Gyurko, Angela M.; Vignoul, Gregory E.; Tien, John K.; Sanchez, Juan M.

1992-11-01

Engineering, University of Texas at Austin, Austin, TX 78712 While much of the high-temperature intermetallics research has centered around Ni3Al and other aluminum-based systems, the present study focuses on the Engel-Brewer Ll2 intermetallic Ir3Zr, which has a melting temperature approaching that of ceramics (2280 °C). Due to limited material availability, the technique of microindentation was used to study both the temperature and time dependence of strength. Because of the widely held belief that certain mechanical properties of intermetallics scale roughly with temperature, Ir3Zr was expected to exhibit high strength. The microhardness was observed to vary from 225 MPa at room temperature to 75 MPa at 1400 °C, which is significantly lower than the behavior of Ni3Al. The activation energy for creep was determined to be 467 kJ/mole, and the stress exponent was found to be 18.2. The ordering energy of this system was calculated to be 0.114 eV. If it can be assumed that high ordering energy correlates to a high antiphase boundary (APB) energy, then the behavior of this system is consistent with a model that predicts highly glissile dislocation cores.

Processing of AlCoCrFeNiTi high entropy alloy by atmospheric plasma spraying

NASA Astrophysics Data System (ADS)

Löbel, M.; Lindner, T.; Kohrt, C.; Lampke, T.

2017-03-01

High Entropy Alloys (HEA) are gaining increasing interest due to their unique combination of properties. Especially the combination of high mechanical strength and hardness with distinct ductility makes them attractive for numerous applications. One interesting alloy system that exhibits excellent properties in bulk state is AlCoCrFeNiTi. A high strength, wear resistance and high-temperature resistance are the necessary requirements for the application in surface engineering. The suitability of blended, mechanically ball milled and inert gas atomized feedstock powders for the development of atmospheric plasma sprayed (APS) coatings is investigated in this study. The ball milled and inert gas atomized powders were characterized regarding their particle morphology, phase composition, chemical composition and powder size distribution. The microstructure and phase composition of the thermal spray coatings produced with different feedstock materials was investigated and compared with the feedstock material. Furthermore, the Vickers hardness (HV) was measured and the wear behavior under different tribological conditions was tested in ball-on-disk, oscillating wear and scratch tests. The results show that all produced feedstock materials and coatings exhibit a multiphase composition. The coatings produced with inert gas atomized feedstock material provide the best wear resistance and the highest degree of homogeneity.

High-Performance Visible-Blind UV Phototransistors Based on n-Type Naphthalene Diimide Nanomaterials.

PubMed

Song, Inho; Lee, Seung-Chul; Shang, Xiaobo; Ahn, Jaeyong; Jung, Hoon-Joo; Jeong, Chan-Uk; Kim, Sang-Wook; Yoon, Woojin; Yun, Hoseop; Kwon, O-Pil; Oh, Joon Hak

2018-04-11

This study investigates the performance of single-crystalline nanomaterials of wide-band gap naphthalene diimide (NDI) derivatives with methylene-bridged aromatic side chains. Such materials are found to be easily used as high-performance, visible-blind near-UV light detectors. NDI single-crystalline nanoribbons are assembled using a simple solution-based process (without solvent-inclusion problems), which is then applied to organic phototransistors (OPTs). Such OPTs exhibit excellent n-channel transistor characteristics, including an average electron mobility of 1.7 cm 2 V -1 s -1 , sensitive UV detection properties with a detection limit of ∼1 μW cm -2 , millisecond-level responses, and detectivity as high as 10 15 Jones, demonstrating the highly sensitive organic visible-blind UV detectors. The high performance of our OPTs originates from the large face-to-face π-π stacking area between the NDI semiconducting cores, which is facilitated by methylene-bridged aromatic side chains. Interestingly, NDI-based nanoribbon OPTs exhibit a distinct visible-blind near-UV detection with an identical detection limit, even under intense visible light illumination (for example, 10 4 times higher intensity than UV light intensity). Our findings demonstrate that wide-band gap NDI-based nanomaterials are highly promising for developing high-performance visible-blind UV photodetectors. Such photodetectors could potentially be used for various applications including environmental and health-monitoring systems.

Nanomechanical properties of distinct fibrillar polymorphs of the protein α-synuclein.

PubMed

Makky, Ali; Bousset, Luc; Polesel-Maris, Jérôme; Melki, Ronald

2016-11-30

Alpha-synuclein (α-Syn) is a small presynaptic protein of 140 amino acids. Its pathologic intracellular aggregation within the central nervous system yields protein fibrillar inclusions named Lewy bodies that are the hallmarks of Parkinson's disease (PD). In solution, pure α-Syn adopts an intrinsically disordered structure and assembles into fibrils that exhibit considerable morphological heterogeneity depending on their assembly conditions. We recently established tightly controlled experimental conditions allowing the assembly of α-Syn into highly homogeneous and pure polymorphs. The latter exhibited differences in their shape, their structure but also in their functional properties. We have conducted an AFM study at high resolution and performed a statistical analysis of fibrillar α-Syn shape and thermal fluctuations to calculate the persistence length to further assess the nanomechanical properties of α-Syn polymorphs. Herein, we demonstrated quantitatively that distinct polymorphs made of the same protein (wild-type α-Syn) show significant differences in their morphology (height, width and periodicity) and physical properties (persistence length, bending rigidity and axial Young's modulus).

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

Zhang, Zijiao; Sheng, Hongwei; Wang, Zhangjie

Combinations of high strength and ductility are hard to attain in metals. Exceptions include materials exhibiting twinning-induced plasticity. To understand how the strength-ductility trade-off can be defeated, we apply in situ, and aberration-corrected scanning, transmission electron microscopy to examine deformation mechanisms in the medium-entropy alloy CrCoNi that exhibits one of the highest combinations of strength, ductility and toughness on record. Ab initio modelling suggests that it has negative stacking-fault energy at 0K and high propensity for twinning. With deformation we find that a three-dimensional (3D) hierarchical twin network forms from the activation of three twinning systems. This serves a dualmore » function: conventional twin-boundary (TB) strengthening from blockage of dislocations impinging on TBs, coupled with the 3D twin network which offers pathways for dislocation glide along, and cross-slip between, intersecting TB-matrix interfaces. The stable twin architecture is not disrupted by interfacial dislocation glide, serving as a continuous source of strength, ductility and toughness.« less

Magnetic Excitations across the Metal-Insulator Transition in the Pyrochlore Iridate Eu2Ir2O7

NASA Astrophysics Data System (ADS)

Chun, Sae Hwan; Yuan, Bo; Casa, Diego; Kim, Jungho; Kim, Chang-Yong; Tian, Zhaoming; Qiu, Yang; Nakatsuji, Satoru; Kim, Young-June

2018-04-01

We report a resonant inelastic x-ray scattering study of the magnetic excitation spectrum in a highly insulating Eu2 Ir2 O7 single crystal that exhibits a metal-insulator transition at TMI=111 (7 ) K . A propagating magnon mode with a 20 meV bandwidth and a 28 meV magnon gap is found in the excitation spectrum at 7 K, which is expected in the all-in-all-out magnetically ordered state. This magnetic excitation exhibits substantial softening as the temperature is raised towards TMI and turns into a highly damped excitation in the paramagnetic phase. Remarkably, the softening occurs throughout the whole Brillouin zone including the zone boundary. This observation is inconsistent with the magnon renormalization expected in a local moment system and indicates that the strength of the electron correlation in Eu2 Ir2 O7 is only moderate, so that electron itinerancy should be taken into account in describing its magnetism.

Geopotential Error Analysis from Satellite Gradiometer and Global Positioning System Observables on Parallel Architecture

NASA Technical Reports Server (NTRS)

Schutz, Bob E.; Baker, Gregory A.

1997-01-01

The recovery of a high resolution geopotential from satellite gradiometer observations motivates the examination of high performance computational techniques. The primary subject matter addresses specifically the use of satellite gradiometer and GPS observations to form and invert the normal matrix associated with a large degree and order geopotential solution. Memory resident and out-of-core parallel linear algebra techniques along with data parallel batch algorithms form the foundation of the least squares application structure. A secondary topic includes the adoption of object oriented programming techniques to enhance modularity and reusability of code. Applications implementing the parallel and object oriented methods successfully calculate the degree variance for a degree and order 110 geopotential solution on 32 processors of the Cray T3E. The memory resident gradiometer application exhibits an overall application performance of 5.4 Gflops, and the out-of-core linear solver exhibits an overall performance of 2.4 Gflops. The combination solution derived from a sun synchronous gradiometer orbit produce average geoid height variances of 17 millimeters.

Theoretical Analysis of Rain Attenuation Probability

NASA Astrophysics Data System (ADS)

Roy, Surendra Kr.; Jha, Santosh Kr.; Jha, Lallan

2007-07-01

Satellite communication technologies are now highly developed and high quality, distance-independent services have expanded over a very wide area. As for the system design of the Hokkaido integrated telecommunications(HIT) network, it must first overcome outages of satellite links due to rain attenuation in ka frequency bands. In this paper theoretical analysis of rain attenuation probability on a slant path has been made. The formula proposed is based Weibull distribution and incorporates recent ITU-R recommendations concerning the necessary rain rates and rain heights inputs. The error behaviour of the model was tested with the loading rain attenuation prediction model recommended by ITU-R for large number of experiments at different probability levels. The novel slant path rain attenuastion prediction model compared to the ITU-R one exhibits a similar behaviour at low time percentages and a better root-mean-square error performance for probability levels above 0.02%. The set of presented models exhibits the advantage of implementation with little complexity and is considered useful for educational and back of the envelope computations.

Nanomechanical properties of distinct fibrillar polymorphs of the protein α-synuclein

NASA Astrophysics Data System (ADS)

Makky, Ali; Bousset, Luc; Polesel-Maris, Jérôme; Melki, Ronald

2016-11-01

Alpha-synuclein (α-Syn) is a small presynaptic protein of 140 amino acids. Its pathologic intracellular aggregation within the central nervous system yields protein fibrillar inclusions named Lewy bodies that are the hallmarks of Parkinson’s disease (PD). In solution, pure α-Syn adopts an intrinsically disordered structure and assembles into fibrils that exhibit considerable morphological heterogeneity depending on their assembly conditions. We recently established tightly controlled experimental conditions allowing the assembly of α-Syn into highly homogeneous and pure polymorphs. The latter exhibited differences in their shape, their structure but also in their functional properties. We have conducted an AFM study at high resolution and performed a statistical analysis of fibrillar α-Syn shape and thermal fluctuations to calculate the persistence length to further assess the nanomechanical properties of α-Syn polymorphs. Herein, we demonstrated quantitatively that distinct polymorphs made of the same protein (wild-type α-Syn) show significant differences in their morphology (height, width and periodicity) and physical properties (persistence length, bending rigidity and axial Young’s modulus).

Geopotential error analysis from satellite gradiometer and global positioning system observables on parallel architectures

NASA Astrophysics Data System (ADS)

Baker, Gregory Allen

The recovery of a high resolution geopotential from satellite gradiometer observations motivates the examination of high performance computational techniques. The primary subject matter addresses specifically the use of satellite gradiometer and GPS observations to form and invert the normal matrix associated with a large degree and order geopotential solution. Memory resident and out-of-core parallel linear algebra techniques along with data parallel batch algorithms form the foundation of the least squares application structure. A secondary topic includes the adoption of object oriented programming techniques to enhance modularity and reusability of code. Applications implementing the parallel and object oriented methods successfully calculate the degree variance for a degree and order 110 geopotential solution on 32 processors of the Cray T3E. The memory resident gradiometer application exhibits an overall application performance of 5.4 Gflops, and the out-of-core linear solver exhibits an overall performance of 2.4 Gflops. The combination solution derived from a sun synchronous gradiometer orbit produce average geoid height variances of 17 millimeters.

An hp symplectic pseudospectral method for nonlinear optimal control

NASA Astrophysics Data System (ADS)

Peng, Haijun; Wang, Xinwei; Li, Mingwu; Chen, Biaosong

2017-01-01

An adaptive symplectic pseudospectral method based on the dual variational principle is proposed and is successfully applied to solving nonlinear optimal control problems in this paper. The proposed method satisfies the first order necessary conditions of continuous optimal control problems, also the symplectic property of the original continuous Hamiltonian system is preserved. The original optimal control problem is transferred into a set of nonlinear equations which can be solved easily by Newton-Raphson iterations, and the Jacobian matrix is found to be sparse and symmetric. The proposed method, on one hand, exhibits exponent convergence rates when the number of collocation points are increasing with the fixed number of sub-intervals; on the other hand, exhibits linear convergence rates when the number of sub-intervals is increasing with the fixed number of collocation points. Furthermore, combining with the hp method based on the residual error of dynamic constraints, the proposed method can achieve given precisions in a few iterations. Five examples highlight the high precision and high computational efficiency of the proposed method.

Magnetotransport Properties in High-Quality Ultrathin Two-Dimensional Superconducting Mo2C Crystals.

PubMed

Wang, Libin; Xu, Chuan; Liu, Zhibo; Chen, Long; Ma, Xiuliang; Cheng, Hui-Ming; Ren, Wencai; Kang, Ning

2016-04-26

Ultrathin transition metal carbides are a class of developing two-dimensional (2D) materials with superconductivity and show great potentials for electrical energy storage and other applications. Here, we report low-temperature magnetotransport measurements on high-quality ultrathin 2D superconducting α-Mo2C crystals synthesized by a chemical vapor deposition method. The magnetoresistance curves exhibit reproducible oscillations at low magnetic fields for temperature far below the superconducting transition temperature of the crystals. We interpret the oscillatory magnetoresistance as a consequence of screening currents circling around the boundary of triangle-shaped terraces found on the surface of ultrathin Mo2C crystals. As the sample thickness decreases, the Mo2C crystals exhibit negative magnetoresistance deep in the superconducting transition regime, which reveals strong phase fluctuations of the superconducting order parameters associated with the superconductor-insulator transition. Our results demonstrate that the ultrathin superconducting Mo2C crystals provide an interesting system for studying rich transport phenomena in a 2D crystalline superconductor with enhanced quantum fluctuations.

Response of Late Cretaceous migrating deltaic facies systems to sea level, tectonics, and sediment supply changes, New Jersey Coastal Plain, U.S.A.

USGS Publications Warehouse

Kulpecz, A.A.; Miller, K.G.; Sugarman, P.J.; Browning, J.V.

2008-01-01

Paleogeographic, isopach, and deltaic lithofacies mapping of thirteen depositional sequences establish a 35 myr high resolution (> 1 Myr) record of Late Cretaceous wave- and tide-influenced deltaic sedimentation. We integrate sequences defined on the basis of lithologic, biostratigraphic, and Sr-isotope stratigraphy from cores with geophysical log data from 28 wells to further develop and extend methods and calibrations of well-log recognition of sequences and facies variations. This study reveals the northeastward migration of depocenters from the Cenomanian (ca. 98 Ma) through the earliest Danian (ca. 64 Ma) and documents five primary phases of paleodeltaic evolution in response to long-term eustatic changes, variations in sediment supply, the location of two long-lived fluvial axes, and thermoflexural basement subsidence: (1) Cenomanian-early Turonian deltaic facies exhibit marine and nonmarine facies and are concentrated in the central coastal plain; (2) high sediment rates, low sea level, and high accommodation rates in the northern coastal plain resulted in thick, marginal to nonmarine mixed-influenced deltaic facies during the Turonign-Coniacian; (3) comparatively low sediment rates and high long-term sea level in the Santonian resulted in a sediment-starved margin with low deltaic influence; (4) well-developed Campanian deltaic sequences expand to the north and exhibit wave reworking and longshore transport of sands, and (5) low sedimentation rates and high long-term sea level during the Maastrichtian resulted in the deposition of a sediment-starved glauconitic shelf. Our study illustrates the widely known variability of mixed-influence deltaic systems, but also documents the relative stability of deltaic facies systems on the 106-107 yr scale, with long periods of cyclically repeating systems tracts controlled by eustasy. Results from the Late Cretaceous further show that although eustasy provides the template for sequences globally, regional tectonics (rates of subsidence and accommodation), changes in sediment supply, proximity to sediment input, and flexural subsidence from depocenter loading determines the regional to local preservation and facies expression of sequences. Copyright ?? 2008, SEPM (Society for Sedimentary Geology).

Aluminum/vacuum multilayer configuration for spatial high-energy electron shielding via electron return effects induced by magnetic field.

PubMed

Chen, Tuo; Tang, Xiaobin; Chen, Feida; Ni, Minxuan; Huang, Hai; Zhang, Yun; Chen, Da

2017-06-26

Radiation shielding of high-energy electrons is critical for successful space missions. However, conventional passive shielding systems exhibit several limitations, such as heavy configuration, poor shielding ability, and strong secondary bremsstrahlung radiation. In this work, an aluminum/vacuum multilayer structure was proposed based on the electron return effects induced by magnetic field. The shielding property of several configurations was evaluated by using the Monte Carlo method. Results showed that multilayer systems presented improved shielding ability to electrons, and less secondary x-ray transmissions than those of conventional systems. Moreover, the influences of magnetic flux density and number of layers on the shielding property of multilayer systems were investigated using a female Chinese hybrid reference phantom based on cumulative dose. In the case of two aluminum layers, the cumulative dose in a phantom gradually decreased with increasing magnetic flux density. The maximum decline rate was found within 0.4-1 Tesla. With increasing layers of configuration, the cumulative dose decreased and the shielding ability improved. This research provides effective shielding measures for future space radiation protection in high-energy electron environments.

Simultaneous three wavelength imaging with a scanning laser ophthalmoscope.

PubMed

Reinholz, F; Ashman, R A; Eikelboom, R H

1999-11-01

Various imaging properties of scanning laser ophthalmoscopes (SLO) such as contrast or depth discrimination, are superior to those of the traditional photographic fundus camera. However, most SLO are monochromatic whereas photographic systems produce colour images, which inherently contain information over a broad wavelength range. An SLO system has been modified to allow simultaneous three channel imaging. Laser light sources in the visible and infrared spectrum were concurrently launched into the system. Using different wavelength triads, digital fundus images were acquired at high frame rates. Favourable wavelengths combinations were established and high contrast, true (red, green, blue) or false (red, green, infrared) colour images of the retina were recorded. The monochromatic frames which form the colour image exhibit improved distinctness of different retinal structures such as the nerve fibre layer, the blood vessels, and the choroid. A multi-channel SLO combines the advantageous imaging properties of a tunable, monochrome SLO with the benefits and convenience of colour ophthalmoscopy. The options to modify parameters such as wavelength, intensity, gain, beam profile, aperture sizes, independently for every channel assign a high degree of versatility to the system. Copyright 1999 Wiley-Liss, Inc.

1.55 µm InAs/GaAs Quantum Dots and High Repetition Rate Quantum Dot SESAM Mode-locked Laser

NASA Astrophysics Data System (ADS)

Zhang, Z. Y.; Oehler, A. E. H.; Resan, B.; Kurmulis, S.; Zhou, K. J.; Wang, Q.; Mangold, M.; Süedmeyer, T.; Keller, U.; Weingarten, K. J.; Hogg, R. A.

2012-06-01

High pulse repetition rate (>=10 GHz) diode-pumped solid-state lasers, modelocked using semiconductor saturable absorber mirrors (SESAMs) are emerging as an enabling technology for high data rate coherent communication systems owing to their low noise and pulse-to-pulse optical phase-coherence. Quantum dot (QD) based SESAMs offer potential advantages to such laser systems in terms of reduced saturation fluence, broader bandwidth, and wavelength flexibility. Here, we describe the development of an epitaxial process for the realization of high optical quality 1.55 µm In(Ga)As QDs on GaAs substrates, their incorporation into a SESAM, and the realization of the first 10 GHz repetition rate QD-SESAM modelocked laser at 1.55 µm, exhibiting ~2 ps pulse width from an Er-doped glass oscillator (ERGO). With a high areal dot density and strong light emission, this QD structure is a very promising candidate for many other applications, such as laser diodes, optical amplifiers, non-linear and photonic crystal based devices.

An Evaluation of High Temperature Airframe Seals for Advanced Hypersonic Vehicles

NASA Technical Reports Server (NTRS)

DeMange, Jeffrey J.; Dunlap, Patrick H.; Steinetz, Bruce M.; Drlik, Gary J.

2007-01-01

High temperature seals are required for advanced hypersonic airframe applications. In this study, both spring tube thermal barriers and innovative wafer seal systems were evaluated under relevant hypersonic test conditions (temperatures, pressures, etc.) via high temperature compression testing and room temperature flow assessments. Thermal barriers composed of a Rene 41 spring tube filled with Saffil insulation and overbraided with a Nextel 312 sheath showed acceptable performance at 1500 F in both short term and longer term compression testing. Nextel 440 thermal barriers with Rene 41 spring tubes and Saffil insulation demonstrated good compression performance up to 1750 F. A silicon nitride wafer seal/compression spring system displayed excellent load performance at temperatures as high as 2200 F and exhibited room temperature leakage values that were only 1/3 those for the spring tube rope seals. For all seal candidates evaluated, no significant degradation in leakage resistance was noted after high temperature compression testing. In addition to these tests, a superalloy seal suitable for dynamic seal applications was optimized through finite element techniques.

A health assessment of high status Christian burials recovered from the Roman-Byzantine archeological site of Elaiussa Sebaste, Turkey.

PubMed

Paine, R R; Vargiu, R; Coppa, A; Morselli, C; Schneider, E E

2007-01-01

The purpose of this study is to assess the state of health of 116 individuals whose remains were excavated from Byzantine period burials underneath the floor of an important Christian basilica from the site of Elaiussa Sebaste, Turkey. Elaiussa Sebaste was a Mediterranean coastal community, which began as a Roman town and continued as an early Christian Byzantine community until the end of the 7th century AD. The burials date from the middle of the 6th through the middle of the 7th centuries AD. We attempt to determine how high social status has influenced the type and frequency of skeletal lesions exhibited in this sample. All strata of this population show a number of chronic and acute health problems as indicated by skeletal lesions. Yet, only the frequency of degenerative joint disease (DJD) differs by sex, with males exhibiting a higher rate of DJD than females, p=0.09. There is no difference in the frequency of trauma among adult males and females. Non-specific skeletal lesions (cribra orbitalia, porotic hyperostosis, and periostitis) often associated with dietary and general stressors, but also with specific systemic diseases, are common in both sexes. The sub-adults primarily exhibit periostitis of the long bones and do not show skeletal lesions specific to malaria. It seems that high social ranking did not prevent serious ailments from affecting the health of individuals living in the Elaiussa Sebaste community.

GSH- and pH-responsive drug delivery system constructed by water-soluble pillar[5]arene and lysine derivative for controllable drug release.

PubMed

Wu, Xuan; Li, Yan; Lin, Chen; Hu, Xiao-Yu; Wang, Leyong

2015-04-21

Novel GSH- and pH-responsive supramolecular vesicles constructed by an amphiphilic inclusion complex formed from water-soluble pillar[5]arene and lysine derivative have been successfully developed, which can efficiently encapsulate anticancer drug MTZ and show rapid MTZ-release in a simulated acidic tumor environment with high GSH concentration, and exhibit potent antitumor activity.

Acute hypoxia during organogenesis affects cardiac autonomic balance in pregnant rats.

PubMed

Maslova, M V; Graf, A V; Maklakova, A S; Krushinskaya, Ya V; Sokolova, N A; Koshelev, V B

2005-02-01

Changes in ECG parameters were studied in pregnant rats exposed to acute hypobaric hypoxia during the period of organogenesis (gestation days 9 to 10). Rats with low, medium, and high tolerance to hypoxia exhibited pronounced autonomic nervous system imbalance, which become apparent as a loss of correlation between various parameters of ECG signals recorded at rest and during exposure to some stress factors existing under normal conditions.

AlGaSb Buffer Layers for Sb-Based Transistors

DTIC Science & Technology

2010-01-01

transistor ( HEMT ), molecular beam epitaxy (MBE), field-effect transistor (FET), buffer layer INTRODUCTION High-electron-mobility transistors ( HEMTs ) with InAs...monolayers/s. The use of thinner buffer layers reduces molecular beam epitaxial growth time and source consumption. The buffer layers also exhibit...source. In addition, some of the flux from an Sb cell in a molecular beam epitaxy (MBE) system will deposit near the mouth of the cell, eventually

Highly Viscoelastic Reverse Wormlike Micellar Systems from a Mixture of Lecithin, Polyglycerol Fatty Acid Monoesters, and an Oil.

PubMed

Hashizaki, Kaname; Imai, Miko; Yako, Shuhei; Tsusaka, Hitomi; Sakanishi, Yuichi; Saito, Yoshihiro; Fujii, Makiko

2017-09-01

We report new lecithin reverse wormlike micelles with high viscoelasticity formed using lecithin/polyglycerol fatty acid monoester (PGLFA)/oil systems. In this study, the influence of the amphiphilicity (i.e., hydrophile-lipophile balance, HLB) of PGLFA on the phase behavior and rheological properties of reverse wormlike micelles was investigated in detail. PGLFAs with degrees of polymerization of polyglycerol varying between 6-40 and constituent fatty acids with chains between 6-18 carbon atoms long were used. Partial phase diagrams of the lecithin/PGLFA/n-decane systems indicated that the appropriate PGLFA could change the lecithin/oil solution into a highly viscoelastic solution comprising reverse wormlike micelles. Rheological measurements showed that all systems that formed reverse wormlike micelles exhibited an unusual phenomenon called "shear-thickening". Furthermore, reverse wormlike micelles grew as the PGLFA concentration increased and the zero-shear viscosity (η 0 ) of the solution rapidly increased. Our results indicate that the magnitude of the maximum η 0 depends on the degree of polymerization of the constituent polyglycerol in the PGLFA, while the size of the reverse micellar region and the highly viscous region in the phase diagram depends on the HLB value of the PGLFA.

Influence of long-wavelength track irregularities on the motion of a high-speed train

NASA Astrophysics Data System (ADS)

Hung, C. F.; Hsu, W. L.

2018-01-01

Vertical track irregularities over viaducts in high-speed rail systems could be possibly caused by concrete creep if pre-stressed concrete bridges are used. For bridge spans that are almost uniformly distributed, track irregularity exhibits a near-regular wave profile that excites car bodies as a high-speed train moves over the bridge system. A long-wavelength irregularity induces low-frequency excitation that may be close to the natural frequencies of the train suspension system, thereby causing significant vibration of the car body. This paper investigates the relationship between the levels of car vibration, bridge vibration, track irregularity, and the train speed. First, this study investigates the vibration levels of a high-speed train and bridge system using 3D finite-element (FE) transient dynamic analysis, before and after adjustment of vertical track irregularities by means of installing shimming plates under rail pads. The analysis models are validated by in situ measurements and on-board measurement. Parametric studies of car body vibration and bridge vibration under three different levels of track irregularity at five train speeds and over two bridge span lengths are conducted using the FE model. Finally, a discontinuous shimming pattern is proposed to avoid vehicle suspension resonance.

Layer-by-layer self-assembled graphene oxide/silica microsphere composites as stationary phase for high performance liquid chromatography.

PubMed

Liang, Xiaojing; Liu, Shujuan; Song, Xinwang; Zhu, Yangwen; Jiang, Shengxiang

2012-11-21

Graphene oxide (GO) has been layer-by-layer assembled onto silica microspheres to form a GO/SiO(2) composite stationary phase. All the characterizations of GO/SiO(2) by elemental analysis, Raman spectroscopy and Fourier transformed infrared spectrometry confirmed that with the increase of the assembled layer, GO gradually increases on the silica surface. The chromatographic properties of bare SiO(2) and GO/SiO(2) with different GO assembled layers show that the amount of GO plays an important role in the separation of analytes. Only the appropriate amount of GO on SiO(2) can perform a good chromatographic separation. The comparison between chromatographic performances of bare SiO(2) column, GO/SiO(2)-2 column and C18 commercial column clearly show that GO/SiO(2)-2 and C18 columns obtained a better separation; GO/SiO(2)-2 exhibits a large π-electron system and C18 exhibits hydrophobicity. The eluting order, peak width and resolution of analyte on GO/SiO(2)-2 column was highly dependent on the size of its π-electron system, while on the C18 column the decisive factor is its hydrophobic property.

Fourier-spectral element approximation of the ion–electron Braginskii system with application to tokamak edge plasma in divertor configuration

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

Minjeaud, Sebastian; INRIA project CASTOR; Pasquetti, Richard, E-mail: richard.pasquetti@unice.fr

Due to the extreme conditions required to produce energy by nuclear fusion in tokamaks, simulating the plasma behavior is an important but challenging task. We focus on the edge part of the plasma, where fluid approaches are probably the best suited, and our approach relies on the Braginskii ion–electron model. Assuming that the electric field is electrostatic, this yields a set of 10 strongly coupled and non-linear conservation equations that exhibit multiscale and anisotropy features. The computational domain is a torus of complex geometrical section, that corresponds to the divertor configuration, i.e. with an “X-point” in the magnetic surfaces. Tomore » capture the complex physics that is involved, high order methods are used: The time-discretization is based on a Strang splitting, that combines implicit and explicit high order Runge–Kutta schemes, and the space discretization makes use of the spectral element method in the poloidal plane together with Fourier expansions in the toroidal direction. The paper thoroughly describes the algorithms that have been developed, provides some numerical validations of the key algorithms and exhibits the results of preliminary numerical experiments. In particular, we point out that the highest frequency of the system is intermediate between the ion and electron cyclotron frequencies.« less

Growth mindset tempers the effects of poverty on academic achievement

PubMed Central

Claro, Susana; Paunesku, David; Dweck, Carol S.

2016-01-01

Two largely separate bodies of empirical research have shown that academic achievement is influenced by structural factors, such as socioeconomic background, and psychological factors, such as students’ beliefs about their abilities. In this research, we use a nationwide sample of high school students from Chile to investigate how these factors interact on a systemic level. Confirming prior research, we find that family income is a strong predictor of achievement. Extending prior research, we find that a growth mindset (the belief that intelligence is not fixed and can be developed) is a comparably strong predictor of achievement and that it exhibits a positive relationship with achievement across all of the socioeconomic strata in the country. Furthermore, we find that students from lower-income families were less likely to hold a growth mindset than their wealthier peers, but those who did hold a growth mindset were appreciably buffered against the deleterious effects of poverty on achievement: students in the lowest 10th percentile of family income who exhibited a growth mindset showed academic performance as high as that of fixed mindset students from the 80th income percentile. These results suggest that students’ mindsets may temper or exacerbate the effects of economic disadvantage on a systemic level. PMID:27432947

Biomimetic HDL nanoparticle mediated tumor targeted delivery of indocyanine green for enhanced photodynamic therapy.

PubMed

Wang, Yazhe; Wang, Cheng; Ding, Yang; Li, Jing; Li, Min; Liang, Xiao; Zhou, Jianping; Wang, Wei

2016-12-01

Photodynamic therapy has emerged as a promising strategy for cancer treatment. To ensure the efficient delivery of a photosensitizer to tumor for anticancer effect, a safe and tumor-specific delivery system is highly desirable. Herein, we introduce a novel biomimetic nanoparticle named rHDL/ICG (rHDL/I), by loading amphiphilic near-infrared (NIR) fluorescent dye indocyanine green (ICG) into reconstituted high density lipoproteins (rHDL). In this system, rHDL can mediate photoprotection effect and receptor-guided tumor-targeting transportation of cargos into cells. Upon NIR irradiation, ICG can generate fluorescent imaging signals for diagnosis and monitoring therapeutic activity, and produce singlet oxygen to trigger photodynamic therapy (PDT). Our studies demonstrated that rHDL/I exhibited excellent size and fluorescence stability, light-triggered controlled release feature, and neglectable hemolytic activity. It also showed equivalent NIR response compared to free ICG under laser irradiation. Importantly, the fluorescent signal of ICG loaded in rHDL/I could be visualized subcellularly in vitro and exhibited metabolic distribution in vivo, presenting superior tumor targeting and internalization. This NIR-triggered image-guided nanoparticle produced outstanding therapeutic outcomes against cancer cells, demonstrating great potential of biomimetic delivery vehicles in future clinical practice. Copyright © 2016 Elsevier B.V. All rights reserved.

Inorganic Nanovehicle Targets Tumor in an Orthotopic Breast Cancer Model

NASA Astrophysics Data System (ADS)

Choi, Goeun; Kwon, Oh-Joon; Oh, Yeonji; Yun, Chae-Ok; Choy, Jin-Ho

2014-03-01

The clinical efficacy of conventional chemotherapeutic agent, methotrexate (MTX), can be limited by its very short plasma half-life, the drug resistance, and the high dosage required for cancer cell suppression. In this study, a new drug delivery system is proposed to overcome such limitations. To realize such a system, MTX was intercalated into layered double hydroxides (LDHs), inorganic drug delivery vehicle, through a co-precipitation route to produce a MTX-LDH nanohybrid with an average particle size of approximately 130 nm. Biodistribution studies in mice bearing orthotopic human breast tumors revealed that the tumor-to-liver ratio of MTX in the MTX-LDH-treated-group was 6-fold higher than that of MTX-treated-one after drug treatment for 2 hr. Moreover, MTX-LDH exhibited superior targeting effect resulting in high antitumor efficacy inducing a 74.3% reduction in tumor volume compared to MTX alone, and as a consequence, significant survival benefits. Annexin-V and propidium iodine dual staining and TUNEL analysis showed that MTX-LDH induced a greater degree of apoptosis than free MTX. Taken together, our data demonstrate that a new MTX-LDH nanohybrid exhibits a superior efficacy profile and improved distribution compared to MTX alone and has the potential to enhance therapeutic efficacy via inhibition of tumor proliferation and induction of apoptosis.

Inorganic nanovehicle targets tumor in an orthotopic breast cancer model.

PubMed

Choi, Goeun; Kwon, Oh-Joon; Oh, Yeonji; Yun, Chae-Ok; Choy, Jin-Ho

2014-03-21

The clinical efficacy of conventional chemotherapeutic agent, methotrexate (MTX), can be limited by its very short plasma half-life, the drug resistance, and the high dosage required for cancer cell suppression. In this study, a new drug delivery system is proposed to overcome such limitations. To realize such a system, MTX was intercalated into layered double hydroxides (LDHs), inorganic drug delivery vehicle, through a co-precipitation route to produce a MTX-LDH nanohybrid with an average particle size of approximately 130 nm. Biodistribution studies in mice bearing orthotopic human breast tumors revealed that the tumor-to-liver ratio of MTX in the MTX-LDH-treated-group was 6-fold higher than that of MTX-treated-one after drug treatment for 2 hr. Moreover, MTX-LDH exhibited superior targeting effect resulting in high antitumor efficacy inducing a 74.3% reduction in tumor volume compared to MTX alone, and as a consequence, significant survival benefits. Annexin-V and propidium iodine dual staining and TUNEL analysis showed that MTX-LDH induced a greater degree of apoptosis than free MTX. Taken together, our data demonstrate that a new MTX-LDH nanohybrid exhibits a superior efficacy profile and improved distribution compared to MTX alone and has the potential to enhance therapeutic efficacy via inhibition of tumor proliferation and induction of apoptosis.

Limestone characterization to model damage from acidic precipitation: Effect of pore structure on mass transfer

USGS Publications Warehouse

Leith, S.D.; Reddy, M.M.; Irez, W.F.; Heymans, M.J.

1996-01-01

The pore structure of Salem limestone is investigated, and conclusions regarding the effect of the pore geometry on modeling moisture and contaminant transport are discussed based on thin section petrography, scanning electron microscopy, mercury intrusion porosimetry, and nitrogen adsorption analyses. These investigations are compared to and shown to compliment permeability and capillary pressure measurements for this common building stone. Salem limestone exhibits a bimodal pore size distribution in which the larger pores provide routes for convective mass transfer of contaminants into the material and the smaller pores lead to high surface area adsorption and reaction sites. Relative permeability and capillary pressure measurements of the air/water system indicate that Salem limestone exhibits high capillarity end low effective permeability to water. Based on stone characterization, aqueous diffusion and convection are believed to be the primary transport mechanisms for pollutants in this stone. The extent of contaminant accumulation in the stone depends on the mechanism of partitioning between the aqueous and solid phases. The described characterization techniques and modeling approach can be applied to many systems of interest such as acidic damage to limestone, mass transfer of contaminants in concrete and other porous building materials, and modeling pollutant transport in subsurface moisture zones.

31-mode piezoelectric micromachined ultrasonic transducer with PZT thick film by granule spraying in vacuum process

NASA Astrophysics Data System (ADS)

Jung, Joontaek; Annapureddy, Venkateswarlu; Hwang, Geon-Tae; Song, Youngsup; Lee, Wonjun; Kang, Woojin; Ryu, Jungho; Choi, Hongsoo

2017-05-01

A piezoelectric micromachined ultrasonic transducer (pMUT) is an ideal device for portable medical diagnosis systems, intravascular ultrasound systems, and ultrasonic cameras because of its favorable characteristics including small size, acoustic impedance matching with the body, low power consumption, and simple integration with the systems. Despite these advantages, practical applications are limited because of insufficient acoustic pressure of the pMUT caused by the thin active piezoelectric layer. Here, we report the fabrication of a thick piezoelectric Pb(Zr,Ti)O3 (PZT) film-based pMUT device having high deflection at low driving voltage using the granule spraying in vacuum (GSV) process. Pre-patterned high-density thick (exceeding 8 μm) PZT films were grown on 6-inch-diameter Si/SiO2/Ti/Pt silicon-on-insulator wafers at room temperature at a high deposition rate of ˜5 μm min-1. The fabrication process using the proposed GSV process was simple and fast, and the deflection of the pMUT exhibited a high value of 0.8 μm.

Application of TL dosemeters for dose distribution measurements at high temperatures in nuclear reactors.

PubMed

Osvay, M; Deme, S

2006-01-01

Al2O3:Mg,Y ceramic thermoluminescence dosemeters were developed at the Institute of Isotopes for high dose applications at room temperatures. The glow curve of Al2O3:Mg,Y exhibits two peaks--one at 250 degrees C (I) and another peak at approximately 400 degrees C (II). In order to extend the application of these dosemeters to high temperatures, the effect of irradiation temperature was investigated using temperature controlled heating system during high dose irradiation at various temperatures (20-100 degrees C). The new calibration and measuring method has been successfully applied for dose mapping within the hermetic zone of the Paks Nuclear Power Plant even at high temperature parts of blocks.

Risk Identification in a Smart Monitoring System Used to Preserve Artefacts Based on Textile Materials

NASA Astrophysics Data System (ADS)

Diaconescu, V. D.; Scripcariu, L.; Mătăsaru, P. D.; Diaconescu, M. R.; Ignat, C. A.

2018-06-01

Exhibited textile-materials-based artefacts can be affected by the environmental conditions. A smart monitoring system that commands an adaptive automatic environment control system is proposed for indoor exhibition spaces containing various textile artefacts. All exhibited objects are monitored by many multi-sensor nodes containing temperature, relative humidity and light sensors. Data collected periodically from the entire sensor network is stored in a database and statistically processed in order to identify and classify the environment risk. Risk consequences are analyzed depending on the risk class and the smart system commands different control measures in order to stabilize the indoor environment conditions to the recommended values and prevent material degradation.

Technology at the zoo: the influence of a touchscreen computer on orangutans and zoo visitors.

PubMed

Perdue, Bonnie M; Clay, Andrea W; Gaalema, Diann E; Maple, Terry L; Stoinski, Tara S

2012-01-01

A computer-controlled touchscreen apparatus (hereafter referred to as "touchscreen") in the orangutan exhibit at Zoo Atlanta provides enrichment to the animals and allows cognitive research to take place on exhibit. This study investigated the impact of the touchscreen on orangutan behavior and visibility, as well as its impact on zoo visitors. Despite previous research suggesting that providing a single computer system may negatively affect orangutan behavior, there was not a significant increase in aggression, stereotypic, or distress-related behaviors following the activation of the on-exhibit touchscreen. We also investigated the possibility that zoo visitors may be negatively affected by technology because it deviates from naturalism. However, we did not find a change in stay time or overall experience rating when the computer was turned on. This research was the first to assess visitor attitudes toward technology at the zoo, and we found that visitors report highly positive attitudes about technology for both animals and visitors. If subjects visited the exhibit when the computer was turned on, they more strongly agreed that orangutans benefit from interacting with computerized enrichment. This study is the first investigation of an on-exhibit touchscreen in group-housed apes; our findings of no negative effects on the animals or zoo visitors and positive attitudes toward technology suggest a significant value of this practice. © 2011 Wiley Periodicals, Inc.

What surface water tells about groundwater in lowlands - and what it does not

NASA Astrophysics Data System (ADS)

Steidl, Jörg; Lischeid, Gunnar; Kalettka, Thomas; Dannowski, Ralf; Merz, Christoph

2017-04-01

Lowland regions often exhibit a high density streams, lakes, ponds and wetlands. This holds, e.g., for Northeast Europe. As a consequence of heterogeneous sedimentation during and after glaciation, and temporarily dead ice blocks left behind in the late stage of the last glaciation, the landscape is now spotted by small depressions that are often filled with water, called kettle holes. Tight coupling between groundwater and surface water with non-stationary gradients and flow directions is often considered rather complex and surely is a challenge for hydrological models. However, on the other hand, close links imply that the one system bears information about the other and vice versa. For example, for the 170 km2 Quillow catchment in Northeast Germany a detailed groundwater map was generated from airborne remote sensing data exclusively, that is, from laser scan data of water level elevation in streams and kettle holes. On average, about 12 points of support per km2 were used. Such a high density can hardly be achieved at that scale based on groundwater wells. The resulting map was checked for consistency and plausibility. The groundwater map allowed delineating the catchments of the single kettle holes in order to assess the impact of land use of water quality. These catchments differed substantially from those determined based on topography. In general, the former usually exhibited a clearly elongated shape of up to some km length, resembling more single groundwater flowpaths rather than exhibiting the typical shape of stream catchments. Analysis of water quality monitoring data revealed that kettle hole water reflected the concentration of earth and alkaline earth metals of the shallow groundwater. However, this did not hold for nutrients and redox sensitive solutes due to rapid biogeochemical turnover in the eutrophic to hypertrophic small lentic systems.

Structure-activity models of oral clearance, cytotoxicity, and LD50: a screen for promising anticancer compounds

PubMed Central

Boik, John C; Newman, Robert A

2008-01-01

Background Quantitative structure-activity relationship (QSAR) models have become popular tools to help identify promising lead compounds in anticancer drug development. Few QSAR studies have investigated multitask learning, however. Multitask learning is an approach that allows distinct but related data sets to be used in training. In this paper, a suite of three QSAR models is developed to identify compounds that are likely to (a) exhibit cytotoxic behavior against cancer cells, (b) exhibit high rat LD50 values (low systemic toxicity), and (c) exhibit low to modest human oral clearance (favorable pharmacokinetic characteristics). Models were constructed using Kernel Multitask Latent Analysis (KMLA), an approach that can effectively handle a large number of correlated data features, nonlinear relationships between features and responses, and multitask learning. Multitask learning is particularly useful when the number of available training records is small relative to the number of features, as was the case with the oral clearance data. Results Multitask learning modestly but significantly improved the classification precision for the oral clearance model. For the cytotoxicity model, which was constructed using a large number of records, multitask learning did not affect precision but did reduce computation time. The models developed here were used to predict activities for 115,000 natural compounds. Hundreds of natural compounds, particularly in the anthraquinone and flavonoids groups, were predicted to be cytotoxic, have high LD50 values, and have low to moderate oral clearance. Conclusion Multitask learning can be useful in some QSAR models. A suite of QSAR models was constructed and used to screen a large drug library for compounds likely to be cytotoxic to multiple cancer cell lines in vitro, have low systemic toxicity in rats, and have favorable pharmacokinetic properties in humans. PMID:18554402

Structure-activity models of oral clearance, cytotoxicity, and LD50: a screen for promising anticancer compounds.

PubMed

Boik, John C; Newman, Robert A

2008-06-13

Quantitative structure-activity relationship (QSAR) models have become popular tools to help identify promising lead compounds in anticancer drug development. Few QSAR studies have investigated multitask learning, however. Multitask learning is an approach that allows distinct but related data sets to be used in training. In this paper, a suite of three QSAR models is developed to identify compounds that are likely to (a) exhibit cytotoxic behavior against cancer cells, (b) exhibit high rat LD50 values (low systemic toxicity), and (c) exhibit low to modest human oral clearance (favorable pharmacokinetic characteristics). Models were constructed using Kernel Multitask Latent Analysis (KMLA), an approach that can effectively handle a large number of correlated data features, nonlinear relationships between features and responses, and multitask learning. Multitask learning is particularly useful when the number of available training records is small relative to the number of features, as was the case with the oral clearance data. Multitask learning modestly but significantly improved the classification precision for the oral clearance model. For the cytotoxicity model, which was constructed using a large number of records, multitask learning did not affect precision but did reduce computation time. The models developed here were used to predict activities for 115,000 natural compounds. Hundreds of natural compounds, particularly in the anthraquinone and flavonoids groups, were predicted to be cytotoxic, have high LD50 values, and have low to moderate oral clearance. Multitask learning can be useful in some QSAR models. A suite of QSAR models was constructed and used to screen a large drug library for compounds likely to be cytotoxic to multiple cancer cell lines in vitro, have low systemic toxicity in rats, and have favorable pharmacokinetic properties in humans.

Novel Polysaccharide Based Polymers and Nanoparticles for Controlled Drug Delivery and Biomedical Imaging

NASA Astrophysics Data System (ADS)

Shalviri, Alireza

The use of polysaccharides as building blocks in the development of drugs and contrast agents delivery systems is rapidly growing. This can be attributed to the outstanding virtues of polysaccharides such as biocompatibility, biodegradability, upgradability, multiple reacting groups and low cost. The focus of this thesis was to develop and characterize novel starch based hydrogels and nanoparticles for delivery of drugs and imaging agents. To this end, two different systems were developed. The first system includes polymer and nanoparticles prepared by graft polymerization of polymethacrylic acid and polysorbate 80 onto starch. This starch based platform nanotechnology was developed using the design principles based on the pathophysiology of breast cancer, with applications in both medical imaging and breast cancer chemotherapy. The nanoparticles exhibited a high degree of doxorubicin loading as well as sustained pH dependent release of the drug. The drug loaded nanoparticles were significantly more effective against multidrug resistant human breast cancer cells compared to free doxorubicin. Systemic administration of the starch based nanoparticles co-loaded with doxorubicin and a near infrared fluorescent probe allowed for non-invasive real time monitoring of the nanoparticles biodistribution, tumor accumulation, and clearance. Systemic administration of the clinically relevant doses of the drug loaded particles to a mouse model of breast cancer significantly enhanced therapeutic efficacy while minimizing side effects compared to free doxorubicin. A novel, starch based magnetic resonance imaging (MRI) contrast agent with good in vitro and in vivo tolerability was formulated which exhibited superior signal enhancement in tumor and vasculature. The second system is a co-polymeric hydrogel of starch and xanthan gum with adjustable swelling and permeation properties. The hydrogels exhibited excellent film forming capability, and appeared to be particularly useful in controlled delivery applications of larger molecular size compounds. The starch based hydrogels, polymers and nanoparticles developed in this work have shown great potentials for controlled drug delivery and biomedical imaging applications.

Lipid-Based Drug Delivery Systems in Cancer Therapy: What Is Available and What Is Yet to Come

PubMed Central

Yingchoncharoen, Phatsapong; Kalinowski, Danuta S.

2016-01-01

Cancer is a leading cause of death in many countries around the world. However, the efficacy of current standard treatments for a variety of cancers is suboptimal. First, most cancer treatments lack specificity, meaning that these treatments affect both cancer cells and their normal counterparts. Second, many anticancer agents are highly toxic, and thus, limit their use in treatment. Third, a number of cytotoxic chemotherapeutics are highly hydrophobic, which limits their utility in cancer therapy. Finally, many chemotherapeutic agents exhibit short half-lives that curtail their efficacy. As a result of these deficiencies, many current treatments lead to side effects, noncompliance, and patient inconvenience due to difficulties in administration. However, the application of nanotechnology has led to the development of effective nanosized drug delivery systems known commonly as nanoparticles. Among these delivery systems, lipid-based nanoparticles, particularly liposomes, have shown to be quite effective at exhibiting the ability to: 1) improve the selectivity of cancer chemotherapeutic agents; 2) lower the cytotoxicity of anticancer drugs to normal tissues, and thus, reduce their toxic side effects; 3) increase the solubility of hydrophobic drugs; and 4) offer a prolonged and controlled release of agents. This review will discuss the current state of lipid-based nanoparticle research, including the development of liposomes for cancer therapy, different strategies for tumor targeting, liposomal formulation of various anticancer drugs that are commercially available, recent progress in liposome technology for the treatment of cancer, and the next generation of lipid-based nanoparticles. PMID:27363439

Early Conventional MRI for Prediction of Neurodevelopmental Impairment in Extremely-Low-Birth-Weight Infants.

PubMed

Slaughter, Laurel A; Bonfante-Mejia, Eliana; Hintz, Susan R; Dvorchik, Igor; Parikh, Nehal A

2016-01-01

Extremely-low-birth-weight (ELBW; ≤1,000 g) infants are at high risk for neurodevelopmental impairments. Conventional brain MRI at term-equivalent age is increasingly used for prediction of outcomes. However, optimal prediction models remain to be determined, especially for cognitive outcomes. The aim was to evaluate the accuracy of a data-driven MRI scoring system to predict neurodevelopmental impairments. 122 ELBW infants had a brain MRI performed at term-equivalent age. Conventional MRI findings were scored with a standardized algorithm and tested using a multivariable regression model to predict neurodevelopmental impairment, defined as one or more of the following at 18-24 months' corrected age: cerebral palsy, bilateral blindness, bilateral deafness requiring amplification, and/or cognitive/language delay. Results were compared with a commonly cited scoring system. In multivariable analyses, only moderate-to-severe gyral maturational delay was a significant predictor of overall neurodevelopmental impairment (OR: 12.6, 95% CI: 2.6, 62.0; p < 0.001). Moderate-to-severe gyral maturational delay also predicted cognitive delay, cognitive delay/death, and neurodevelopmental impairment/death. Diffuse cystic abnormality was a significant predictor of cerebral palsy (OR: 33.6, 95% CI: 4.9, 229.7; p < 0.001). These predictors exhibited high specificity (range: 94-99%) but low sensitivity (30-67%) for the above outcomes. White or gray matter scores, determined using a commonly cited scoring system, did not show significant association with neurodevelopmental impairment. In our cohort, conventional MRI at term-equivalent age exhibited high specificity in predicting neurodevelopmental outcomes. However, sensitivity was suboptimal, suggesting additional clinical factors and biomarkers are needed to enable accurate prognostication. © 2016 S. Karger AG, Basel.

A Concept for a Mobile Remote Manipulator System

NASA Technical Reports Server (NTRS)

Mikulus, M. M., Jr.; Bush, H. G.; Wallsom, R. E.; Jensen, J. K.

1985-01-01

A conceptual design for a Mobile Remote Manipulator System (MRMS) is presented. This concept does not require continuous rails for mobility (only guide pins at truss hardpoints) and is very compact, being only one bay square. The MRMS proposed is highly maneuverable and is able to move in any direction along the orthogonal guide pin array under complete control at all times. The proposed concept would greatly enhance the safety and operational capabilities of astronauts performing EVA functions such as structural assembly, payload transport and attachment, space station maintenance, repair or modification, and future spacecraft construction or servicing. The MRMS drive system conceptual design presented is a reasonably simple mechanical device which can be designed to exhibit high reliability. Developmentally, all components of the proposed MRMS either exist or are considered to be completely state of the art designs requiring minimal development, features which should enhance reliability and minimize costs.

Pattern matching techniques for correcting low-confidence OCR words in a known context

NASA Astrophysics Data System (ADS)

Ford, Glenn; Hauser, Susan E.; Le, Daniel X.; Thoma, George R.

2000-12-01

A commercial OCR system is a key component of a system developed at the National Library of Medicine for the automated extraction of bibliographic fields from biomedical journals. This 5-engine OCR system, while exhibiting high performance overall, does not reliably convert very small characters, especially those that are in italics. As a result, the 'affiliations' field that typically contains such characters in most journals, is not captured accurately, and requires a disproportionately high manual input. To correct this problem, dictionaries have been created from words occurring in this field (e.g., university, department, street addresses, names of cities, etc.) from 230,000 articles already processed. The OCR output corresponding to the affiliation field is then matched against these dictionary entries by approximate string-matching techniques, and the ranked matches are presented to operators for verification. This paper outlines the techniques employed and the results of a comparative evaluation.

Molecular approaches to third generation photovoltaics: photochemical up-conversion

NASA Astrophysics Data System (ADS)

Cheng, Yuen Yap; Fückel, Burkhard; Roberts, Derrick A.; Khoury, Tony; Clady, Rapha"l. G. C. R.; Tayebjee, Murad J. Y.; Piper, Roland; Ekins-Daukes, N. J.; Crossley, Maxwell J.; Schmidt, Timothy W.

2010-08-01

We have investigated a photochemical up-conversion system comprising a molecular mixture of a palladium porphyrin to harvest light, and a polycyclic aromatic hydrocarbon to emit light. The energy of harvested photons is stored as molecular triplet states which then annihilate to bring about up-converted fluorescence. The limiting efficiency of such triplet-triplet annihilation up-conversion has been believed to be 11% for some time. However, by rigorously investigating the kinetics of delayed fluorescence following pulsed excitation, we demonstrate instantaneous annihilation efficiencies exceeding 40%, and limiting efficiencies for the current system of ~60%. We attribute the high efficiencies obtained to the electronic structure of the emitting molecule, which exhibits an exceptionally high T2 molecular state. We utilize the kinetic data obtained to model an up-converting layer irradiated with broadband sunlight, finding that ~3% efficiencies can be obtained with the current system, with this improving dramatically upon optimization of various parameters.

Aviation-fuel lubricity evaluation

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

Not Available

1988-07-01

Fuel-system components have experienced problems with the slipperiness or lubricity of the fuel back to the early 1960's. As a consequence of the level of refinement necessary for the PWA 523 fuel (now designated MIL-T-38219 grade JP-7) to obtain its high-temperature stability, many of the polar compounds contributing to lubricity had been removed, resulting in abnormal hydraulic fuel-pump wear. A lubricity-enhancing compound was developed (PWA 536) to eliminate the wear problem. High-pressure piston-type fuel pumps were one of the first parts of the engine fuel system to exhibit problems related to fuel properties. One early problem manifested itself as corrosionmore » of silver-plated slipper pads and was related to carryover of residual-chlorides fuel. Fuel controls were another part of the engine fuel system susceptible to fuel properties. Lack of lubricity agents caused fuel control sliding servo valves to stick.« less

A simple-architecture fibered transmission system for dissemination of high stability 100 MHz signals

NASA Astrophysics Data System (ADS)

Bakir, A.; Rocher, C.; Maréchal, B.; Bigler, E.; Boudot, R.; Kersalé, Y.; Millo, J.

2018-05-01

We report on the development of a simple-architecture fiber-based frequency distribution system used to transfer high frequency stability 100 MHz signals. This work is focused on the emitter and the receiver performances that allow the transmission of the radio-frequency signal over an optical fiber. The system exhibits a residual fractional frequency stability of 1 × 10-14 at 1 s integration time and in the low 10-16 range after 100 s. These performances are suitable to transfer the signal of frequency references such as those of a state-of-the-art hydrogen maser without any phase noise compensation scheme. As an application, we demonstrate the dissemination of such a signal through a 100 m long optical fiber without any degradation. The proposed setup could be easily extended for operating frequencies in the 10 MHz-1 GHz range.

A novel process for comprehensive utilization of vanadium slag

NASA Astrophysics Data System (ADS)

Liu, Li-ying; Du, Tao; Tan, Wen-jun; Zhang, Xin-pu; Yang, Fan

2016-02-01

Traditional processes for treating vanadium slag generate a huge volume of solid residue and a large amount of harmful gas, which cause serious environmental problems. In this study, a new process for the comprehensive utilization of vanadium slag was proposed, wherein zeolite A and a V2O5/TiO2 system were synthesized. The structural properties of the as-synthesized zeolite A and the V2O5/TiO2 system were characterized using various experimental techniques, including X-ray diffraction, X-ray fluorescence, scanning electron microscopy, and infrared spectroscopy. The results reveal that zeolite A and the V2O5/TiO2 system are successfully obtained with high purity. The results of gas adsorption measurements indicate that the prepared zeolite A exhibits high selectivity for CO2 over N2 and is a candidate material for CO2 capture from flue-gas streams.

Secure self-calibrating quantum random-bit generator

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

Fiorentino, M.; Santori, C.; Spillane, S. M.

2007-03-15

Random-bit generators (RBGs) are key components of a variety of information processing applications ranging from simulations to cryptography. In particular, cryptographic systems require 'strong' RBGs that produce high-entropy bit sequences, but traditional software pseudo-RBGs have very low entropy content and therefore are relatively weak for cryptography. Hardware RBGs yield entropy from chaotic or quantum physical systems and therefore are expected to exhibit high entropy, but in current implementations their exact entropy content is unknown. Here we report a quantum random-bit generator (QRBG) that harvests entropy by measuring single-photon and entangled two-photon polarization states. We introduce and implement a quantum tomographicmore » method to measure a lower bound on the 'min-entropy' of the system, and we employ this value to distill a truly random-bit sequence. This approach is secure: even if an attacker takes control of the source of optical states, a secure random sequence can be distilled.« less

Aquatic food production modules in bioregenerative life support systems based on higher plants

NASA Astrophysics Data System (ADS)

Bluem, V.; Paris, F.

Most bioregenerative life support systems (BLSS) are based on gravitropic higher plants which exhibit growth and seed generation disturbances in microgravity. Even when used for a lunar or martian base the reduced gravity may induce a decreased productivity in comparison to Earth. Therefore, the implementation of aquatic biomass production modules in higher plant and/or hybrid BLSS may compensate for this and offer, in addition, the possibility to produce animal protein for human nutrition. It was shown on the SLS-89 and SLS-90 space shuttle missions with the C.E.B.A.S.-MINI MODULE that the edible non gravitropic rootless higher aquatic plant Ceratophyllum demeresum exhibits an undisturbed high biomass production rate in space and that the teleost fish species, Xiphophorus helleri, adapts rapidly to space conditions without loss of its normal reproductive functions. Based on these findings a series of ground-based aquatic food production systems were developed which are disposed for utilization in space. These are plant production bioreactors for the species mentioned above and another suitable candidate, the lemnacean (duckweed) species, Wolffia arrhiza. Moreover, combined intensive aquaculture systems with a closed food loop between herbivorous fishes and aquatic and land plants are being developed which may be suitable for integration into a BLSS of higher complexity.

Comparison of the BD Viper System with XTR Technology to the Gen-Probe APTIMA COMBO 2 Assay using the TIGRIS DTS system for the detection of Chlamydia trachomatis and Neisseria gonorrhoeae in urine specimens.

PubMed

Mushanski, Linda M; Brandt, Ken; Coffin, Nicolette; Levett, Paul N; Horsman, Gregory B; Rank, Elliot L

2012-07-01

Performances of the BD ProbeTec Chlamydia trachomatis (CT)/Neisseria Gonorrhoeae (GC) Q(x) Amplified DNA Assay reagents on a BD Viper System with XTR Technology and APTIMA COMBO 2 Assay reagents on a TIGRIS DTS platform, for detection of both CT and GC were compared. A total of 1018 first-void urine specimens were tested for the presence of CT and GC DNA using the 2 assays. CT was detected in 143 specimens (14%). Eight specimens exhibited discordant results, and they were divided equally between the 2 assays. Based on the original results, the overall agreement for CT was 99.2%, with 97.1% and 99.5% in agreement with positive and negative specimens, respectively. Cohen's Kappa was 0.967. GC was detected in 27 specimens (2.6%). Two specimens exhibited discordant results, and they were divided equally between the 2 assays. Based on the original results, the overall agreement was 99.8%, with 96.2% and 99.9% in agreement for positive and negative specimens, respectively. Cohen's Kappa was 0.961. There was a high level of agreement between the systems for both CT and GC detection.

Nanostructured lipid carriers as novel ophthalmic delivery system for mangiferin: improving in vivo ocular bioavailability.

PubMed

Liu, Rui; Liu, Zhidong; Zhang, Chengui; Zhang, Boli

2012-10-01

The aim of this study was to develop a novel nanostructured lipid carriers (NLCs) system to improve ocular bioavailability of mangiferin (MGN) for the potential treatment of cataract. The physicochemical properties of MGN-loaded NLC (MGN-NLC) formulation were characterized by particle size, polydispersity index, zeta potential, entrapment efficiency, drug loading, morphological property, and crystalline state. in vitro characteristics were investigated by drug release from NLC system, physical stability, and corneal permeation through excised rabbit cornea. Moreover, in vivo ocular tolerability was assessed by a modified Draize test and histological microscopy. Preocular retention capability was evaluated by slit-lamp observation. Pharmacokinetic study in the aqueous humor was performed by microdialysis technique. Transmission electron microscopy depicted spherical and uniform morphology. Differential scanning calorimetry and X-ray diffractometry displayed imperfect crystalline lattice. The optimized MGN-NLC formulation exhibited a sustained drug release with 3 months stability and 4.31-fold increase of in vitro corneal permeation. Furthermore, in vivo studies exhibited a high tolerance in the ocular tissues and prolonged drug retention capacity on the corneal surface. Finally, pharmacokinetic study suggested a 5.69-fold increase of ocular bioavailability compared with MGN solution (MGN-SOL). Therefore, NLC system is a promising approach for ocular delivery of MGN. Copyright © 2012 Wiley Periodicals, Inc.

Do marmosets care to share? Oxytocin treatment reduces prosocial behavior toward strangers.

PubMed

Mustoe, Aaryn C; Cavanaugh, Jon; Harnisch, April M; Thompson, Breanna E; French, Jeffrey A

2015-05-01

Cooperatively-breeding and socially-monogamous primates, like marmosets and humans, exhibit high levels of social tolerance and prosociality toward others. Oxytocin (OXT) generally facilitates prosocial behavior, but there is growing recognition that OXT modulation of prosocial behavior is shaped by the context of social interactions and by other motivational states such as arousal or anxiety. To determine whether prosociality varies based on social context, we evaluated whether marmoset donors (Callithrix penicillata) preferentially rewarded pairmates versus opposite-sex strangers in a prosocial food-sharing task. To examine potential links among OXT, stress systems, and prosociality, we evaluated whether pretrial cortisol levels in marmosets altered the impact of OXT on prosocial responses. Marmosets exhibited spontaneous prosociality toward others, but they did so preferentially toward strangers compared to their pairmates. When donor marmosets were treated with marmoset-specific Pro(8)-OXT, they exhibited reduced prosociality toward strangers compared to marmosets treated with saline or consensus-mammalian Leu(8)-OXT. When pretrial cortisol levels were lower, marmosets exhibited higher prosociality toward strangers. These findings demonstrate that while marmosets show spontaneous prosocial responses toward others, they do so preferentially toward opposite-sex strangers. Cooperative breeding may be associated with the expression of prosociality, but the existence of a pair-bond between marmoset partners appears to be neither necessary nor sufficient for the expression of spontaneous prosocial responses. Furthermore, high prosociality toward strangers is significantly reduced in marmosets treated with Pro(8)-OXT, suggesting that OXT does not universally enhance prosociality, but, rather OXT modulation of prosocial behavior varies depending on social context. Copyright © 2015 Elsevier Inc. All rights reserved.

Do marmosets care to share? Oxytocin treatment reduces prosocial behavior toward strangers

PubMed Central

Mustoe, Aaryn C.; Cavanaugh, Jon; Harnisch, April M.; Thompson, Breanna E.; French, Jeffrey A.

2015-01-01

Cooperatively-breeding and socially-monogamous primates, like marmosets and humans, exhibit high levels of social tolerance and prosociality toward others. Oxytocin (OXT) generally facilitates prosocial behavior, but there is growing recognition that OXT modulation of prosocial behavior is shaped by the context of social interactions and by other motivational states such as arousal or anxiety. To determine whether prosociality varies based on social context, we evaluated whether marmoset donors (Callithrix penicillata) preferentially rewarded pairmates versus opposite-sex strangers in a prosocial food-sharing task. To examine potential links among OXT, stress systems, and prosociality, we evaluated whether pretrial cortisol levels in marmosets altered the impact of OXT on prosocial responses. Marmosets exhibited spontaneous prosociality toward others, but they did so preferentially toward strangers compared to their pairmates. When donor marmosets were treated with marmoset-specific Pro8-OXT, they exhibited reduced prosociality toward strangers compared to marmosets treated with saline or consensus-mammalian Leu8-OXT. When pretrial cortisol levels were lower, marmosets exhibited higher prosociality toward strangers. These findings demonstrate that while marmosets show spontaneous prosocial responses toward others, they do so preferentially toward opposite-sex strangers. Cooperative breeding may be associated with the expression of prosociality, but the existence of a pair-bond between marmoset partners appears to be neither necessary nor sufficient for the expression of spontaneous prosocial responses. Further, high prosociality toward strangers is significantly reduced in marmosets treated with Pro8-OXT, suggesting that OXT does not universally enhance prosociality, but, rather OXT modulation of prosocial behavior varies depending on social context. PMID:25934057

Quantitative fluorescence and elastic scattering tissue polarimetry using an Eigenvalue calibrated spectroscopic Mueller matrix system.

PubMed

Soni, Jalpa; Purwar, Harsh; Lakhotia, Harshit; Chandel, Shubham; Banerjee, Chitram; Kumar, Uday; Ghosh, Nirmalya

2013-07-01

A novel spectroscopic Mueller matrix system has been developed and explored for both fluorescence and elastic scattering polarimetric measurements from biological tissues. The 4 × 4 Mueller matrix measurement strategy is based on sixteen spectrally resolved (λ = 400 - 800 nm) measurements performed by sequentially generating and analyzing four elliptical polarization states. Eigenvalue calibration of the system ensured high accuracy of Mueller matrix measurement over a broad wavelength range, either for forward or backscattering geometry. The system was explored for quantitative fluorescence and elastic scattering spectroscopic polarimetric studies on normal and precancerous tissue sections from human uterine cervix. The fluorescence spectroscopic Mueller matrices yielded an interesting diattenuation parameter, exhibiting differences between normal and precancerous tissues.

Controlling aliased dynamics in motion systems? An identification for sampled-data control approach

NASA Astrophysics Data System (ADS)

Oomen, Tom

2014-07-01

Sampled-data control systems occasionally exhibit aliased resonance phenomena within the control bandwidth. The aim of this paper is to investigate the aspect of these aliased dynamics with application to a high performance industrial nano-positioning machine. This necessitates a full sampled-data control design approach, since these aliased dynamics endanger both the at-sample performance and the intersample behaviour. The proposed framework comprises both system identification and sampled-data control. In particular, the sampled-data control objective necessitates models that encompass the intersample behaviour, i.e., ideally continuous time models. Application of the proposed approach on an industrial wafer stage system provides a thorough insight and new control design guidelines for controlling aliased dynamics.

Cross-Correlations and Structures of Aero-Engine Gas Path System Based on DCCA Coefficient and Rooted Tree

NASA Astrophysics Data System (ADS)

Dong, Keqiang; Fan, Jie; Gao, You

2015-12-01

Identifying the mutual interaction is a crucial problem that facilitates the understanding of emerging structures in complex system. We here focus on aero-engine dynamic as an example of complex system. By applying the detrended cross-correlation analysis (DCCA) coefficient method to aero-engine gas path system, we find that the low-spool rotor speed (N1) and high-spool rotor speed (N2) fluctuation series exhibit cross-correlation characteristic. Further, we employ detrended cross-correlation coefficient matrix and rooted tree to investigate the mutual interactions of other gas path variables. The results can infer that the exhaust gas temperature (EGT), N1, N2, fuel flow (WF) and engine pressure ratio (EPR) are main gas path parameters.

Dynamical tides in highly eccentric binaries: chaos, dissipation, and quasi-steady state

NASA Astrophysics Data System (ADS)

Vick, Michelle; Lai, Dong

2018-05-01

Highly eccentric binary systems appear in many astrophysical contexts, ranging from tidal capture in dense star clusters, precursors of stellar disruption by massive black holes, to high-eccentricity migration of giant planets. In a highly eccentric binary, the tidal potential of one body can excite oscillatory modes in the other during a pericentre passage, resulting in energy exchange between the modes and the binary orbit. These modes exhibit one of three behaviours over multiple passages: low-amplitude oscillations, large-amplitude oscillations corresponding to a resonance between the orbital frequency and the mode frequency, and chaotic growth, with the mode energy reaching a level comparable to the orbital binding energy. We study these phenomena with an iterative map that includes mode dissipation, fully exploring how the mode evolution depends on the orbital and mode properties of the system. The dissipation of mode energy drives the system towards a quasi-steady state, with gradual orbital decay punctuated by resonances. We quantify the quasi-steady state and the long-term evolution of the system. A newly captured star around a black hole can experience significant orbital decay and heating due to the chaotic growth of the mode amplitude and dissipation. A giant planet pushed into a high-eccentricity orbit may experience a similar effect and become a hot or warm Jupiter.

Rapid Catalyst Screening by a Continuous-Flow Microreactor Interfaced with Ultra High Pressure Liquid Chromatography

PubMed Central

Fang, Hui; Xiao, Qing; Wu, Fanghui; Floreancig, Paul E.; Weber, Stephen G.

2010-01-01

A high-throughput screening system for homogeneous catalyst discovery has been developed by integrating a continuous-flow capillary-based microreactor with ultra-high pressure liquid chromatography (UHPLC) for fast online analysis. Reactions are conducted in distinct and stable zones in a flow stream that allows for time and temperature regulation. UHPLC detection at high temperature allows high throughput online determination of substrate, product, and byproduct concentrations. We evaluated the efficacies of a series of soluble acid catalysts for an intramolecular Friedel-Crafts addition into an acyliminium ion intermediate within one day and with minimal material investment. The effects of catalyst loading, reaction time, and reaction temperature were also screened. This system exhibited high reproducibility for high-throughput catalyst screening and allowed several acid catalysts for the reaction to be identified. Major side products from the reactions were determined through off-line mass spectrometric detection. Er(OTf)3, the catalyst that showed optimal efficiency in the screening, was shown to be effective at promoting the cyclization reaction on a preparative scale. PMID:20666502

Starch Applications for Delivery Systems

NASA Astrophysics Data System (ADS)

Li, Jason

2013-03-01

Starch is one of the most abundant and economical renewable biopolymers in nature. Starch molecules are high molecular weight polymers of D-glucose linked by α-(1,4) and α-(1,6) glycosidic bonds, forming linear (amylose) and branched (amylopectin) structures. Octenyl succinic anhydride modified starches (OSA-starch) are designed by carefully choosing a proper starch source, path and degree of modification. This enables emulsion and micro-encapsulation delivery systems for oil based flavors, micronutrients, fragrance, and pharmaceutical actives. A large percentage of flavors are encapsulated by spray drying in today's industry due to its high throughput. However, spray drying encapsulation faces constant challenges with retention of volatile compounds, oxidation of sensitive compound, and manufacturing yield. Specialty OSA-starches were developed suitable for the complex dynamics in spray drying and to provide high encapsulation efficiency and high microcapsule quality. The OSA starch surface activity, low viscosity and film forming capability contribute to high volatile retention and low active oxidation. OSA starches exhibit superior performance, especially in high solids and high oil load encapsulations compared with other hydrocolloids. The submission is based on research and development of Ingredion

Three-dimensional graphene-polypyrrole hybrid electrochemical actuator

NASA Astrophysics Data System (ADS)

Liu, Jia; Wang, Zhi; Zhao, Yang; Cheng, Huhu; Hu, Chuangang; Jiang, Lan; Qu, Liangti

2012-11-01

The advancement of mechanical actuators benefits from the development of new structural materials with prominent properties. A novel three-dimensional (3D) hydrothermally converted graphene and polypyrrole (G-PPy) hybrid electrochemical actuator is presented, which is prepared via a convenient hydrothermal process, followed by in situ electropolymerization of pyrrole. The 3D pore-interconnected G-PPy pillar exhibits strong actuation responses superior to pure graphene and PPy film. In response to the low potentials of +/-0.8 V, the saturated strain of 3D G-PPy pillar can reach a record of 2.5%, which is more than 10 times higher than that of carbon nanotube film and about 3 times that of unitary graphene film under an applied potential of +/-1.2 V. Also, the 3D G-PPy actuator exhibits high actuation durability with high operating load as demonstrated by an 11 day continuous measurement. Finally, a proof-of-concept application of 3D G-PPy as smart filler for on/off switch is also demonstrated, which indicates the great potential of the 3D G-PPy structure developed in this study for advanced actuator systems.The advancement of mechanical actuators benefits from the development of new structural materials with prominent properties. A novel three-dimensional (3D) hydrothermally converted graphene and polypyrrole (G-PPy) hybrid electrochemical actuator is presented, which is prepared via a convenient hydrothermal process, followed by in situ electropolymerization of pyrrole. The 3D pore-interconnected G-PPy pillar exhibits strong actuation responses superior to pure graphene and PPy film. In response to the low potentials of +/-0.8 V, the saturated strain of 3D G-PPy pillar can reach a record of 2.5%, which is more than 10 times higher than that of carbon nanotube film and about 3 times that of unitary graphene film under an applied potential of +/-1.2 V. Also, the 3D G-PPy actuator exhibits high actuation durability with high operating load as demonstrated by an 11 day continuous measurement. Finally, a proof-of-concept application of 3D G-PPy as smart filler for on/off switch is also demonstrated, which indicates the great potential of the 3D G-PPy structure developed in this study for advanced actuator systems. Electronic supplementary information (ESI) available: Experimental setup for fabrication of G-PPy hybrid structure, and movie showing the on/off response of G-PPy filler. See DOI: 10.1039/c2nr32699j

Synthesis and Raman spectroscopy of a layered SiS2 phase at high pressures

NASA Astrophysics Data System (ADS)

Wang, Yu; Jiang, Shu-Qing; Goncharov, Alexander F.; Gorelli, Federico A.; Chen, Xiao-Jia; Plašienka, Dušan; MartoÅák, Roman; Tosatti, Erio; Santoro, Mario

2018-01-01

Dichalcogenides are known to exhibit layered solid phases, at ambient and high pressures, where 2D layers of chemically bonded formula units are held together by van der Waals forces. These materials are of great interest for solid-state sciences and technology, along with other 2D systems such as graphene and phosphorene. SiS2 is an archetypal model system of the most fundamental interest within this ensemble. Recently, high pressure (GPa) phases with Si in octahedral coordination by S have been theoretically predicted and also experimentally found to occur in this compound. At variance with stishovite in SiO2, which is a 3D network of SiO6 octahedra, the phases with octahedral coordination in SiS2 are 2D layered. Very importantly, this type of semiconducting material was theoretically predicted to exhibit continuous bandgap closing with pressure to a poor metallic state at tens of GPa. We synthesized layered SiS2 with octahedral coordination in a diamond anvil cell at 7.5-9 GPa, by laser heating together elemental S and Si at 1300-1700 K. Indeed, Raman spectroscopy up to 64.4 GPa is compatible with continuous bandgap closing in this material with the onset of either weak metallicity or of a narrow bandgap semiconductor state with a large density of defect-induced, intra-gap energy levels, at about 57 GPa. Importantly, our investigation adds up to the fundamental knowledge of layered dichalcogenides.

Odorant-binding proteins display high affinities for behavioral attractants and repellents in the natural predator Chrysopa pallens.

PubMed

Li, Zhao-Qun; Zhang, Shuai; Luo, Jun-Yu; Wang, Si-Bao; Dong, Shuang-Lin; Cui, Jin-Jie

2015-07-01

Chrysopa pallens is an important natural predator of various pests in many different cropping systems. Understanding the sophisticated olfactory system of insect antennae is crucial for studying the physiological bases of olfaction and could also help enhance the effectiveness of C. pallens in biological control. However, functional studies of the olfactory genes in C. pallens are still lacking. In this study, we cloned five odorant-binding protein (OBP) genes from C. pallens (CpalOBPs). Quantitative RT-PCR results indicated that the five CpalOBPs had different tissue expression profiles. Ligand-binding assays showed that farnesol, farnesene, cis-3-hexenyl hexanoate, geranylacetone, beta-ionone, octyl aldehyde, decanal, nerolidol (Ki<20 μM), and especially 2-pentadecanone (Ki=1.19 μM) and 2-hexyl-1-decanol (Ki=0.37 μM) strongly bound to CpalOBP2. CpalOBP15 exhibited high binding affinities for beta-ionone, 2-tridecanone, trans-nerolidol, and dodecyl aldehyde. Behavioral trials using the 14 compounds exhibiting high binding affinities for the CpalOBPs revealed that nine were able to elicit significant behavioral responses from C. pallens. Among them, farnesene and its corresponding alcohol, farnesol, elicited remarkable repellent behavioral responses from C. pallens. Our study provides several compounds that could be selected to develop slow-release agents that attract/repel C. pallens and to improve the search for strategies to eliminate insect pests. Copyright © 2015 Elsevier Inc. All rights reserved.

The effect of fluorescent nanodiamonds on neuronal survival and morphogenesis

NASA Astrophysics Data System (ADS)

Huang, Yung-An; Kao, Chun-Wei; Liu, Kuang-Kai; Huang, Hou-Syun; Chiang, Ming-Han; Soo, Ching-Ren; Chang, Huan-Cheng; Chiu, Tzai-Wen; Chao, Jui-I.; Hwang, Eric

2014-11-01

Nanodiamond (ND) has emerged as a promising carbon nanomaterial for therapeutic applications. In previous studies, ND has been reported to have outstanding biocompatibility and high uptake rate in various cell types. ND containing nitrogen-vacancy centers exhibit fluorescence property is called fluorescent nanodiamond (FND), and has been applied for bio-labeling agent. However, the influence and application of FND on the nervous system remain elusive. In order to study the compatibility of FND on the nervous system, neurons treated with FNDs in vitro and in vivo were examined. FND did not induce cytotoxicity in primary neurons from either central (CNS) or peripheral nervous system (PNS); neither did intracranial injection of FND affect animal behavior. The neuronal uptake of FNDs was confirmed using flow cytometry and confocal microscopy. However, FND caused a concentration-dependent decrease in neurite length in both CNS and PNS neurons. Time-lapse live cell imaging showed that the reduction of neurite length was due to the spatial hindrance of FND on advancing axonal growth cone. These findings demonstrate that FNDs exhibit low neuronal toxicity but interfere with neuronal morphogenesis, and should be taken into consideration when applications involve actively growing neurites (e.g. nerve regeneration).