Aerodynamic efficiency of a bioinspired flapping wing rotor at low Reynolds number

PubMed Central

Guo, S.

2018-01-01

This study investigates the aerodynamic efficiency of a bioinspired flapping wing rotor kinematics which combines an active vertical flapping motion and a passive horizontal rotation induced by aerodynamic thrust. The aerodynamic efficiencies for producing both vertical lift and horizontal thrust of the wing are obtained using a quasi-steady aerodynamic model and two-dimensional (2D) CFD analysis at Reynolds number of 2500. The calculated efficiency data show that both efficiencies (propulsive efficiency-ηp, and efficiency for producing lift-Pf) of the wing are optimized at Strouhal number (St) between 0.1 and 0.5 for a range of wing pitch angles (upstroke angle of attack αu less than 45°); the St for high Pf (St = 0.1 ∼ 0.3) is generally lower than for high ηp (St = 0.2 ∼ 0.5), while the St for equilibrium rotation states lies between the two. Further systematic calculations show that the natural equilibrium of the passive rotating wing automatically converges to high-efficiency states: above 85% of maximum Pf can be obtained for a wide range of prescribed wing kinematics. This study provides insight into the aerodynamic efficiency of biological flyers in cruising flight, as well as practical applications for micro air vehicle design. PMID:29657749

Superconducting Technology Assessment

DTIC Science & Technology

2005-08-01

designing a single compressor pulse tube between the high pump frequency which produces good efficiency at the higher...noise models must be extended to sub-micron JJs. Transmission line models must be extended to the high frequency regime. VHDL models and methods ...temperatures and the low frequencies needed at low temperatures. Hybrid Sterling- pulse tube coolers allow the higher efficiency of a Sterling high

High-Efficiency Polycrystalline CdS/CdTe Solar Cells on Buffered Commercial TCO-Coated Glass

NASA Astrophysics Data System (ADS)

Colegrove, E.; Banai, R.; Blissett, C.; Buurma, C.; Ellsworth, J.; Morley, M.; Barnes, S.; Gilmore, C.; Bergeson, J. D.; Dhere, R.; Scott, M.; Gessert, T.; Sivananthan, Siva

2012-10-01

Multiple polycrystalline CdS/CdTe solar cells with efficiencies greater than 15% were produced on buffered, commercially available Pilkington TEC Glass at EPIR Technologies, Inc. (EPIR, Bolingbrook, IL) and verified by the National Renewable Energy Laboratory (NREL). n-CdS and p-CdTe were grown by chemical bath deposition (CBD) and close space sublimation, respectively. Samples with sputter-deposited CdS were also investigated. Initial results indicate that this is a viable dry-process alternative to CBD for production-scale processing. Published results for polycrystalline CdS/CdTe solar cells with high efficiencies are typically based on cells using research-grade transparent conducting oxides (TCOs) requiring high-temperature processing inconducive to low-cost manufacturing. EPIR's results for cells on commercial glass were obtained by implementing a high-resistivity SnO2 buffer layer and by optimizing the CdS window layer thickness. The high-resistivity buffer layer prevents the formation of CdTe-TCO junctions, thereby maintaining a high open-circuit voltage and fill factor, whereas using a thin CdS layer reduces absorption losses and improves the short-circuit current density. EPIR's best device demonstrated an NREL-verified efficiency of 15.3%. The mean efficiency of hundreds of cells produced with a buffer layer between December 2010 and June 2011 is 14.4%. Quantum efficiency results are presented to demonstrate EPIR's progress toward NREL's best-published results.

A Silicon–Singlet Fission Tandem Solar Cell Exceeding 100% External Quantum Efficiency with High Spectral Stability

PubMed Central

2017-01-01

After 60 years of research, silicon solar cell efficiency saturated close to the theoretical limit, and radically new approaches are needed to further improve the efficiency. The use of tandem systems raises this theoretical power conversion efficiency limit from 34% to 45%. We present the advantageous spectral stability of using voltage-matched tandem solar cells with respect to their traditional series-connected counterparts and experimentally demonstrate how singlet fission can be used to produce simple voltage-matched tandems. Our singlet fission silicon–pentacene tandem solar cell shows efficient photocurrent addition. This allows the tandem system to benefit from carrier multiplication and to produce an external quantum efficiency exceeding 100% at the main absorption peak of pentacene. PMID:28261671

High-performance axicon lenses based on high-contrast, multilayer gratings

NASA Astrophysics Data System (ADS)

Doshay, Sage; Sell, David; Yang, Jianji; Yang, Rui; Fan, Jonathan A.

2018-01-01

Axicon lenses are versatile optical elements that can convert Gaussian beams to Bessel-like beams. In this letter, we demonstrate that axicons operating with high efficiencies and at large angles can be produced using high-contrast, multilayer gratings made from silicon. Efficient beam deflection of incident monochromatic light is enabled by higher-order optical modes in the silicon structure. Compared to diffractive devices made from low-contrast materials such as silicon dioxide, our multilayer devices have a relatively low spatial profile, reducing shadowing effects and enabling high efficiencies at large deflection angles. In addition, the feature sizes of these structures are relatively large, making the fabrication of near-infrared devices accessible with conventional optical lithography. Experimental lenses with deflection angles as large as 40° display field profiles that agree well with theory. Our concept can be used to design optical elements that produce higher-order Bessel-like beams, and the combination of high-contrast materials with multilayer architectures will more generally enable new classes of diffractive photonic structures.

A study of the effectiveness and energy efficiency of ultrasonic emulsification.

PubMed

Li, Wu; Leong, Thomas S H; Ashokkumar, Muthupandian; Martin, Gregory J O

2017-12-20

Three essential experimental parameters in the ultrasonic emulsification process, namely sonication time, acoustic amplitude and processing volume, were individually investigated, theoretically and experimentally, and correlated to the emulsion droplet sizes produced. The results showed that with a decrease in droplet size, two kinetic regions can be separately correlated prior to reaching a steady state droplet size: a fast size reduction region and a steady state transition region. In the fast size reduction region, the power input and sonication time could be correlated to the volume-mean diameter by a power-law relationship, with separate power-law indices of -1.4 and -1.1, respectively. A proportional relationship was found between droplet size and processing volume. The effectiveness and energy efficiency of droplet size reduction was compared between ultrasound and high-pressure homogenisation (HPH) based on both the effective power delivered to the emulsion and the total electric power consumed. Sonication could produce emulsions across a broad range of sizes, while high-pressure homogenisation was able to produce emulsions at the smaller end of the range. For ultrasonication, the energy efficiency was higher at increased power inputs due to more effective droplet breakage at high ultrasound intensities. For HPH the consumed energy efficiency was improved by operating at higher pressures for fewer passes. At the laboratory scale, the ultrasound system required less electrical power than HPH to produce an emulsion of comparable droplet size. The energy efficiency of HPH is greatly improved at large scale, which may also be true for larger scale ultrasonic reactors.

Vortex focusing of ions produced in corona discharge.

PubMed

Kolomiets, Yuri N; Pervukhin, Viktor V

2013-06-15

Completeness of the ion transportation into an analytical path defines the efficiency of ionization analysis techniques. This is of particular importance for atmospheric pressure ionization sources like corona discharge, electrospray, ionization with radioactive ((3)H, (63)Ni) isotopes that produce nonuniform spatial distribution of sample ions. The available methods of sample ion focusing are either efficient at reduced pressure (~1Torr) or feature high sample losses. This paper deals with experimental research into atmospheric pressure focusing of unipolar (positive) ions using a highly swirled air stream with a well-defined vortex core. Effects of electrical fields from corona needle and inlet capillary of mass spectrometer on collection efficiency is considered. We used a corona discharge to produce an ionized unipolar sample. It is shown experimentally that with an electrical field barrier efficient transportation and focusing of an ionized sample are possible only when a metal plate restricting the stream and provided with an opening covered with a grid is used. This gives a five-fold increase of the transportation efficiency. It is shown that the electric field barrier in the vortex sampling region reduces the efficiency of remote ionized sample transportation two times. The difference in the efficiency of light ion focusing observed may be explained by a high mobility and a significant effect of the electric field barrier upon them. It is possible to conclude based on the experimental data that the presence of the field barrier narrows considerably (more than by one and half) the region of the vortex sample ion focusing. Copyright © 2013 Elsevier B.V. All rights reserved.

Report of high quantum efficiency photocathode at Milano

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

Michelato, P.

R D activity on high quantum efficiency alkali antimonide photocathode is in progress at Milano, in the context of the ARES program. Inside a preliminary preparation chamber, Cs[sub 3]Sb layers with qunatum efficiency up to 9% (at [lambda]=543.5 nm) and lifetime of some days has been recently produced on copper, stainless steel and niobium, using a reproducible deposition procedure adapted to the material of the different substrata.

Processing mechanics of alternate twist ply (ATP) yarn technology

NASA Astrophysics Data System (ADS)

Elkhamy, Donia Said

Ply yarns are important in many textile manufacturing processes and various applications. The primary process used for producing ply yarns is cabling. The speed of cabling is limited to about 35m/min. With the world's increasing demands of ply yarn supply, cabling is incompatible with today's demand activated manufacturing strategies. The Alternate Twist Ply (ATP) yarn technology is a relatively new process for producing ply yarns with improved productivity and flexibility. This technology involves self plying of twisted singles yarn to produce ply yarn. The ATP process can run more than ten times faster than cabling. To implement the ATP process to produce ply yarns there are major quality issues; uniform Twist Profile and yarn Twist Efficiency. The goal of this thesis is to improve these issues through process modeling based on understanding the physics and processing mechanics of the ATP yarn system. In our study we determine the main parameters that control the yarn twist profile. Process modeling of the yarn twist across different process zones was done. A computational model was designed to predict the process parameters required to achieve a square wave twist profile. Twist efficiency, a measure of yarn torsional stability and bulk, is determined by the ratio of ply yarn twist to singles yarn twist. Response Surface Methodology was used to develop the processing window that can reproduce ATP yarns with high twist efficiency. Equilibrium conditions of tensions and torques acting on the yarns at the self ply point were analyzed and determined the pathway for achieving higher twist efficiency. Mechanistic modeling relating equilibrium conditions to the twist efficiency was developed. A static tester was designed to zoom into the self ply zone of the ATP yarn. A computer controlled, prototypic ATP machine was constructed and confirmed the mechanistic model results. Optimum parameters achieving maximum twist efficiency were determined in this study. The successful results of this work have led to the filing of a US patent disclosing the method for producing ATP yarns with high yarn twist efficiency using a high convergence angle at the self ply point together with applying ply torque.

High Efficiency, Low Cost Solar Cells Manufactured Using 'Silicon Ink' on Thin Crystalline Silicon Wafers

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

Antoniadis, H.

Reported are the development and demonstration of a 17% efficient 25mm x 25mm crystalline Silicon solar cell and a 16% efficient 125mm x 125mm crystalline Silicon solar cell, both produced by Ink-jet printing Silicon Ink on a thin crystalline Silicon wafer. To achieve these objectives, processing approaches were developed to print the Silicon Ink in a predetermined pattern to form a high efficiency selective emitter, remove the solvents in the Silicon Ink and fuse the deposited particle Silicon films. Additionally, standard solar cell manufacturing equipment with slightly modified processes were used to complete the fabrication of the Silicon Ink highmore » efficiency solar cells. Also reported are the development and demonstration of a 18.5% efficient 125mm x 125mm monocrystalline Silicon cell, and a 17% efficient 125mm x 125mm multicrystalline Silicon cell, by utilizing high throughput Ink-jet and screen printing technologies. To achieve these objectives, Innovalight developed new high throughput processing tools to print and fuse both p and n type particle Silicon Inks in a predetermined pat-tern applied either on the front or the back of the cell. Additionally, a customized Ink-jet and screen printing systems, coupled with customized substrate handling solution, customized printing algorithms, and a customized ink drying process, in combination with a purchased turn-key line, were used to complete the high efficiency solar cells. This development work delivered a process capable of high volume producing 18.5% efficient crystalline Silicon solar cells and enabled the Innovalight to commercialize its technology by the summer of 2010.« less

Development of a high efficiency thin silicon solar cell

NASA Technical Reports Server (NTRS)

Storti, G.; Culik, J.; Wrigley, C.

1980-01-01

Significant improvements in open-circuit voltage and conversion efficiency, even on relatively high bulk resistivity silicon, were achieved by using a screen-printed aluminum paste back surface field. A 4 sq cm 50 micron m thick cell was fabricated from textured 10 omega-cm silicon which had an open-circuit voltage of 595 mV and AMO conversion efficiency at 25 C of 14.3%. The best 4 sq cm 50 micron thick cell (2 omega-cm silicon) produced had an open-circuit voltage of 607 mV and an AMO conversion efficiency of 15%. Processing modifications are described which resulted in better front contact integrity and reduced breakage. These modifications were utilized in the thin cell pilot line to fabricate 4 sq cm cells with an average AMO conversion efficiency at 25 C of better than 12.5% and with lot yields as great as 51% of starts; a production rate of 10,000 cells per month was demonstrated. A pilot line was operated which produced large area (25 cm) ultra-thin cells with an average AMO conversion efficiency at 25 deg of better than 11.5% and a lot yield as high as 17%.

Solar-Power System Produces High-Pressure Steam

NASA Technical Reports Server (NTRS)

Lansing, F. L.

1985-01-01

Combination of three multistaged solar collectors produces highpressure steam for large-scale continuously operating turbines for generating mechanical or electrical energy. Superheated water vapor drives turbines, attaining an overall system efficiency about 22 percent.

The LICPA-driven collider—a novel efficient tool for the production of ultra-high pressures in condensed media

NASA Astrophysics Data System (ADS)

Badziak, J.; Krousky, E.; Kucharik, M.; Liska, R.

2016-03-01

Generation of strong shock waves for the production of Mbar or Gbar pressures is a topic of high relevance for contemporary research in various domains, including inertial confinement fusion, laboratory astrophysics, planetology and material science. The pressures in the multi-Mbar range can be produced by the shocks generated using chemical explosions, light-gas guns, Z-pinch machines or lasers. Higher pressures, in the sub-Gbar or Gbar range are attainable only with nuclear explosions or laser-based methods. Unfortunately, due to the low efficiency of energy conversion from a laser to the shock (below a few percent), multi-kJ, multi-beam lasers are needed to produce such pressures with these methods. Here, we propose and investigate a novel scheme for generating high-pressure shocks which is much more efficient than the laser-based schemes known so far. In the proposed scheme, the shock is generated in a dense target by the impact of a fast projectile driven by the laser-induced cavity pressure acceleration (LICPA) mechanism. Using two-dimensional hydrodynamic simulations and the measurements performed at the kilojoule PALS laser facility it is shown that in the LICPA-driven collider the laser-to-shock energy conversion efficiency can reach a very high value ~ 15-20 % and, as a result, the shock pressure ~ 0.5-1 Gbar can be produced using lasers of energy <= 0.5 kJ. On the other hand, the pressures in the multi-Mbar range could be produced in this collider with low-energy (~ 10 J) lasers available on the market. It would open up the possibility of conducting research in high energy-density science also in small, university-class laboratories.

Aerodynamic efficiency of a bioinspired flapping wing rotor at low Reynolds number.

PubMed

Li, H; Guo, S

2018-03-01

This study investigates the aerodynamic efficiency of a bioinspired flapping wing rotor kinematics which combines an active vertical flapping motion and a passive horizontal rotation induced by aerodynamic thrust. The aerodynamic efficiencies for producing both vertical lift and horizontal thrust of the wing are obtained using a quasi-steady aerodynamic model and two-dimensional (2D) CFD analysis at Reynolds number of 2500. The calculated efficiency data show that both efficiencies (propulsive efficiency- η p , and efficiency for producing lift- P f ) of the wing are optimized at Strouhal number ( St ) between 0.1 and 0.5 for a range of wing pitch angles (upstroke angle of attack α u less than 45°); the St for high P f ( St  = 0.1 ∼ 0.3) is generally lower than for high η p ( St  = 0.2 ∼ 0.5), while the St for equilibrium rotation states lies between the two. Further systematic calculations show that the natural equilibrium of the passive rotating wing automatically converges to high-efficiency states: above 85% of maximum P f can be obtained for a wide range of prescribed wing kinematics. This study provides insight into the aerodynamic efficiency of biological flyers in cruising flight, as well as practical applications for micro air vehicle design.

Low-Cost High-Pressure Hydrogen Generator

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

Cropley, Cecelia C.; Norman, Timothy J.

Electrolysis of water, particularly in conjunction with renewable energy sources, is potentially a cost-effective and environmentally friendly method of producing hydrogen at dispersed forecourt sites, such as automotive fueling stations. The primary feedstock for an electrolyzer is electricity, which could be produced by renewable sources such as wind or solar that do not produce carbon dioxide or other greenhouse gas emissions. However, state-of-the-art electrolyzer systems are not economically competitive for forecourt hydrogen production due to their high capital and operating costs, particularly the cost of the electricity used by the electrolyzer stack. In this project, Giner Electrochemical Systems, LLC (GES)more » developed a low cost, high efficiency proton-exchange membrane (PEM) electrolysis system for hydrogen production at moderate pressure (300 to 400 psig). The electrolyzer stack operates at differential pressure, with hydrogen produced at moderate pressure while oxygen is evolved at near-atmospheric pressure, reducing the cost of the water feed and oxygen handling subsystems. The project included basic research on catalysts and membranes to improve the efficiency of the electrolysis reaction as well as development of advanced materials and component fabrication methods to reduce the capital cost of the electrolyzer stack and system. The project culminated in delivery of a prototype electrolyzer module to the National Renewable Energy Laboratory for testing at the National Wind Technology Center. Electrolysis cell efficiency of 72% (based on the lower heating value of hydrogen) was demonstrated using an advanced high-strength membrane developed in this project. This membrane would enable the electrolyzer system to exceed the DOE 2012 efficiency target of 69%. GES significantly reduced the capital cost of a PEM electrolyzer stack through development of low cost components and fabrication methods, including a 60% reduction in stack parts count. Economic analysis indicates that hydrogen could be produced for $3.79 per gge at an electricity cost of $0.05/kWh by the lower-cost PEM electrolyzer developed in this project, assuming high-volume production of large-scale electrolyzer systems.« less

Facile and Scalable Fabrication of Highly Efficient Lead Iodide Perovskite Thin-Film Solar Cells in Air Using Gas Pump Method.

PubMed

Ding, Bin; Gao, Lili; Liang, Lusheng; Chu, Qianqian; Song, Xiaoxuan; Li, Yan; Yang, Guanjun; Fan, Bin; Wang, Mingkui; Li, Chengxin; Li, Changjiu

2016-08-10

Control of the perovskite film formation process to produce high-quality organic-inorganic metal halide perovskite thin films with uniform morphology, high surface coverage, and minimum pinholes is of great importance to highly efficient solar cells. Herein, we report on large-area light-absorbing perovskite films fabrication with a new facile and scalable gas pump method. By decreasing the total pressure in the evaporation environment, the gas pump method can significantly enhance the solvent evaporation rate by 8 times faster and thereby produce an extremely dense, uniform, and full-coverage perovskite thin film. The resulting planar perovskite solar cells can achieve an impressive power conversion efficiency up to 19.00% with an average efficiency of 17.38 ± 0.70% for 32 devices with an area of 5 × 2 mm, 13.91% for devices with a large area up to 1.13 cm(2). The perovskite films can be easily fabricated in air conditions with a relative humidity of 45-55%, which definitely has a promising prospect in industrial application of large-area perovskite solar panels.

Genome Sequence of Lactobacillus rhamnosus Strain CASL, an Efficient l-Lactic Acid Producer from Cheap Substrate Cassava

PubMed Central

Yu, Bo; Su, Fei; Wang, Limin; Zhao, Bo; Qin, Jiayang; Ma, Cuiqing; Xu, Ping; Ma, Yanhe

2011-01-01

Lactobacillus rhamnosus is a type of probiotic bacteria with industrial potential for l-lactic acid production. We announce the draft genome sequence of L. rhamnosus CASL (2,855,156 bp with a G+C content of 46.6%), which is an efficient producer of l-lactic acid from cheap, nonfood substrate cassava with a high production titer. PMID:22123765

Production of Dissolved Organic Matter During Doliolid Feeding

NASA Astrophysics Data System (ADS)

Castellane, N. J.; Paffenhofer, G. A.; Stubbins, A.

2016-02-01

The biological carbon pump (BCP) draws carbon dioxide out of the atmosphere and buries it at the seafloor. The efficiency of the BCP is determined in part by the sinking rates of particulate organic carbon (POC) from ocean surface waters. Zooplankton can package POC into fecal pellets with higher sinking rates than their food source (e.g. phytoplankton), increasing the efficiency of the BCP. However, dissolved organic carbon (DOC) is also produced as zooplankton ingest and egest food, reducing the efficiency of BCP. The pelagic tunicate Dolioletta gegenbauri (doliolid) is a gelatinous zooplankton found at high concentrations in shelf waters, including our study site: the South Atlantic Bight. Doliolids are efficient grazers capable of stripping large quantities of phytoplankton from the water column. To determine the balance between pellet formation and DOC production during feeding, doliolids (6-7 mm gonozooids) were placed in natural seawater amended with a live phytoplankton food source and incubated on a plankton wheel. Dissolved organic matter (DOM) released directly to the water as well as the water soluble fraction of pellet organic matter were quantified and optically characterized. Colored dissolved organic matter (CDOM) absorbance and fluorescence spectra revealed that doliolid feeding produces DOM with optical properties that are commonly indicative of newly produced, highly biolabile DOM of microbial origin. Based upon these optical characteristics, doliolid-produced DOM is expected to be highly bio-labile in the environment and therefore rapidly degraded by surface ocean microbes shunting phytoplankton-derived organic carbon out of the BCP and back to dissolved inorganic carbon.

LARGE-SCALE HYDROGEN PRODUCTION FROM NUCLEAR ENERGY USING HIGH TEMPERATURE ELECTROLYSIS

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

James E. O'Brien

2010-08-01

Hydrogen can be produced from water splitting with relatively high efficiency using high-temperature electrolysis. This technology makes use of solid-oxide cells, running in the electrolysis mode to produce hydrogen from steam, while consuming electricity and high-temperature process heat. When coupled to an advanced high temperature nuclear reactor, the overall thermal-to-hydrogen efficiency for high-temperature electrolysis can be as high as 50%, which is about double the overall efficiency of conventional low-temperature electrolysis. Current large-scale hydrogen production is based almost exclusively on steam reforming of methane, a method that consumes a precious fossil fuel while emitting carbon dioxide to the atmosphere. Demandmore » for hydrogen is increasing rapidly for refining of increasingly low-grade petroleum resources, such as the Athabasca oil sands and for ammonia-based fertilizer production. Large quantities of hydrogen are also required for carbon-efficient conversion of biomass to liquid fuels. With supplemental nuclear hydrogen, almost all of the carbon in the biomass can be converted to liquid fuels in a nearly carbon-neutral fashion. Ultimately, hydrogen may be employed as a direct transportation fuel in a “hydrogen economy.” The large quantity of hydrogen that would be required for this concept should be produced without consuming fossil fuels or emitting greenhouse gases. An overview of the high-temperature electrolysis technology will be presented, including basic theory, modeling, and experimental activities. Modeling activities include both computational fluid dynamics and large-scale systems analysis. We have also demonstrated high-temperature electrolysis in our laboratory at the 15 kW scale, achieving a hydrogen production rate in excess of 5500 L/hr.« less

High-Efficiency Silicon Carbide (SiC) Converters. Delivery Order 0001: Development of High-Temperature, High-Power, High-Efficiency, High-Voltage Converters Using Silicon Carbide

DTIC Science & Technology

2004-03-01

32 Silicon Dioxide as a Mask ......................................................... 34 Silicon Nitride as a Mask...phosphorous (P), and arsenic (As) for n-type material and aluminum (Al), boron (B), beryllium (Be), gallium (Ga), oxygen (O), and scandium (Sc) for...O2 in carbon tetrafluoride (CF4), nitrogen trifluoride (NF3), and sulfur hexafluoride (SF6) were observed because these gases produce high fluorine

Pilot scale high solids anaerobic digestion of steam autoclaved municipal solid waste (MSW) pulp

USDA-ARS?s Scientific Manuscript database

Steam autoclaving is an efficient method for the separation and recovery of nearly all organics from MSW, yet a reliable alternative outlet for the large volume of organics produced has not yet been successfully demonstrated. The material produced by the autoclave contains a high concentration of s...

High-efficiency holograms fixed in lithium niobate after recording using a digital fringe stabilization system.

PubMed

Arizmendi, Luis; Ambite, Emilio J

2012-02-20

We used a digital feedback control loop system to produce reproducible fixed volume transmission holograms of high diffraction efficiency. Different strategies were investigated to obtain holograms of good quality and the highest refractive index modulation depth. Using this control system, we were able to record holograms with stationary fringes. Additionally to using the stationary fringe recording, a double recording-fixing schedule resulted in being the most appropriate one to produce reproducible holograms of better characteristics. This strategy is discussed and compared with other already established ones. © 2012 Optical Society of America

Efficient High Order Central Schemes for Multi-Dimensional Hamilton-Jacobi Equations: Talk Slides

NASA Technical Reports Server (NTRS)

Bryson, Steve; Levy, Doron; Biegel, Brian R. (Technical Monitor)

2002-01-01

This viewgraph presentation presents information on the attempt to produce high-order, efficient, central methods that scale well to high dimension. The central philosophy is that the equations should evolve to the point where the data is smooth. This is accomplished by a cyclic pattern of reconstruction, evolution, and re-projection. One dimensional and two dimensional representational methods are detailed, as well.

Plasma instability control toward high fluence, high energy x-ray continuum source

NASA Astrophysics Data System (ADS)

Poole, Patrick; Kirkwood, Robert; Wilks, Scott; Blue, Brent

2017-10-01

X-ray source development at Omega and NIF seeks to produce powerful radiation with high conversion efficiency for material effects studies in extreme fluence environments. While current K-shell emission sources can achieve tens of kJ on NIF up to 22 keV, the conversion efficiency drops rapidly for higher Z K-alpha energies. Pulsed power devices are efficient generators of MeV bremsstrahlung x-rays but are unable to produce lower energy photons in isolation, and so a capability gap exists for high fluence x-rays in the 30 - 100 keV range. A continuum source under development utilizes instabilities like Stimulated Raman Scattering (SRS) to generate plasma waves that accelerate electrons into high-Z converter walls. Optimizing instabilities using existing knowledge on their elimination will allow sufficiently hot and high yield electron distributions to create a superior bremsstrahlung x-ray source. An Omega experiment has been performed to investigate the optimization of SRS and high energy x-rays using Au hohlraums with parylene inner lining and foam fills, producing 10× greater x-ray yield at 50 keV than conventional direct drive experiments on the facility. Experiment and simulation details on this campaign will be presented. This work was performed under the auspices of the US DoE by LLNL under Contract No. DE-AC52-07NA27344.

Efficiency and cost advantages of an advanced-technology nuclear electrolytic hydrogen-energy production facility

NASA Technical Reports Server (NTRS)

Donakowski, T. D.; Escher, W. J. D.; Gregory, D. P.

1977-01-01

The concept of an advanced-technology (viz., 1985 technology) nuclear-electrolytic water electrolysis facility was assessed for hydrogen production cost and efficiency expectations. The facility integrates (1) a high-temperature gas-cooled nuclear reactor (HTGR) operating a binary work cycle, (2) direct-current (d-c) electricity generation via acyclic generators, and (3) high-current-density, high-pressure electrolyzers using a solid polymer electrolyte (SPE). All subsystems are close-coupled and optimally interfaced for hydrogen production alone (i.e., without separate production of electrical power). Pipeline-pressure hydrogen and oxygen are produced at 6900 kPa (1000 psi). We found that this advanced facility would produce hydrogen at costs that were approximately half those associated with contemporary-technology nuclear electrolysis: $5.36 versus $10.86/million Btu, respectively. The nuclear-heat-to-hydrogen-energy conversion efficiency for the advanced system was estimated as 43%, versus 25% for the contemporary system.

LASER APPLICATIONS AND OTHER TOPICS IN QUANTUM ELECTRONICS: Mechanism for shock wave merging in magnetised plasma: criteria and efficiency of formation of low-frequency magnetosonic waves

NASA Astrophysics Data System (ADS)

Tishchenko, V. N.; Shaikhislamov, I. F.

2010-08-01

The mechanism of merging of shock waves produced by a pulsating energy source is considered for magnetised plasma. The criteria for the emergence of this mechanism are found and its high efficiency for producing low-frequency magnetosonic waves, which have the form of a jet and propagate at large distances without attenuation, is shown.

High Power Klystrons for Efficient Reliable High Power Amplifiers.

DTIC Science & Technology

1980-11-01

techniques to obtain high overall efficiency. One is second harmonic space charge bunching. This is a process whereby the fundamental and second harmonic...components of the space charge waves in the electron beam of a microwave tube are combined to produce more highly concentrated electron bunches raising the...the drift lengths to enhance the 2nd harmonic component in the space charge waves. The latter method was utilized in the VKC-7790. Computer

Design and Applications of Rapid Image Tile Producing Software Based on Mosaic Dataset

NASA Astrophysics Data System (ADS)

Zha, Z.; Huang, W.; Wang, C.; Tang, D.; Zhu, L.

2018-04-01

Map tile technology is widely used in web geographic information services. How to efficiently produce map tiles is key technology for rapid service of images on web. In this paper, a rapid producing software for image tile data based on mosaic dataset is designed, meanwhile, the flow of tile producing is given. Key technologies such as cluster processing, map representation, tile checking, tile conversion and compression in memory are discussed. Accomplished by software development and tested by actual image data, the results show that this software has a high degree of automation, would be able to effectively reducing the number of IO and improve the tile producing efficiency. Moreover, the manual operations would be reduced significantly.

Production technology for high efficiency ion implanted solar cells

NASA Technical Reports Server (NTRS)

Kirkpatrick, A. R.; Minnucci, J. A.; Greenwald, A. C.; Josephs, R. H.

1978-01-01

Ion implantation is being developed for high volume automated production of silicon solar cells. An implanter designed for solar cell processing and able to properly implant up to 300 4-inch wafers per hour is now operational. A machine to implant 180 sq m/hr of solar cell material has been designed. Implanted silicon solar cells with efficiencies exceeding 16% AM1 are now being produced and higher efficiencies are expected. Ion implantation and transient processing by pulsed electron beams are being integrated with electrostatic bonding to accomplish a simple method for large scale, low cost production of high efficiency solar cell arrays.

Unrevealed part of myosin's powerstroke accounts for high efficiency of muscle contraction.

PubMed

Bibó, András; Károlyi, György; Kovács, Mihály

2017-09-01

Myosin II, the motor protein driving muscle contraction, uses energy of ATP hydrolysis to produce movement along actin. The key step of energy transduction is the powerstroke, involving rotation of myosin's lever while myosin is attached to actin. Macroscopic measurements indicated high thermodynamic efficiency for energy conversion. However, single-molecule experiments indicated lower efficiency, provoking a long-standing discrepancy. Based on the Fluctuation-Dissipation Theorem, we built a sufficiently detailed but low degree-of-freedom model reconstructing the entire mechanoenzymatic cycle. We show that a high axial stiffness of the lever during an initial, experimentally yet unrevealed part of the powerstroke results in a short-time, ratchet-like Kramers effect, and is responsible for the missing efficiency. The second part of the powerstroke is an Eyring-like relaxation that dominantly contributes to lever rotation, but produces only a minor part of the work. The model reveals the structural background of myosin's capability to function as a robust molecular engine and a very precise load sensor as well. Our model also suggests an explanation for the malfunction of myosins harboring mutations that lead to hypertrophic cardiomyopathies with most severe clinical prognosis. The model explains how a force-transmitting device within a biological motor can enable high energetic efficiency. Copyright © 2017 Elsevier B.V. All rights reserved.

Metabolic differences of industrial acarbose-producing Actinoplanes sp. A56 under various osmolality levels.

PubMed

Li, Kun-tai; Peng, Wei-fu; Xia, Wei; Huang, Lin; Cheng, Xin

2016-01-01

Many investigations have revealed that a certain concentration of osmolality was indispensable for efficient acarbose production, but little information was available on the response mechanism of acarbose-producing strains to osmotic stress. By using the gas chromatography-mass spectrometry (GC-MS) analysis coupled with the enzyme activity determination of central carbon metabolism, the present work investigated the metabolic characteristics of industrial acarbose-producing Actinoplanes sp. A56 under various osmolality levels. Relatively high osmolality (450-500 mOsm/kg) appeared to favor efficient acarbose production by Actinoplanes sp. A56, although it inhibited cell growth. Further GC-MS analysis showed that fatty acids were the uppermost differential intracellular metabolites under various osmolality levels, and the relatively high osmolality resulted in increases in levels of fatty acids.

Producing high-quality negatives from ERTS black-and-white transparancies

Treesearch

Richard J. Myhre

1973-01-01

A method has been devised for producing high-quality black-and-white negatives quickly and efficiently from dense transparencies orgininating from Earth Resources Technology Satellite imagery. Transparencies are evaluated on a standard light source to determine exposure and processing information needed for making negatives. A “System ASA Rating” was developed by...

High Efficiency mm-Wave Transmitter Array

DTIC Science & Technology

2016-09-01

SECURITY CLASSIFICATION OF: High efficiency, high power transmitters integrated in silicon at 45, 94 and 138 GHz were developed. Our approach...employs CMOS-SOI and SiGe HBT unit amplifiers, power -combined in free-space using antenna arrays to attain high power levels. In the baseline approach...the-art were made. At 45GHz, a single CMOS chip produced an RF power of 630mW, which yielded an EIRP of 1. REPORT DATE (DD-MM-YYYY) 4. TITLE AND

Efficient phase contrast imaging in STEM using a pixelated detector. Part 1: Experimental demonstration at atomic resolution

DOE PAGES

Pennycook, Timothy J.; Lupini, Andrew R.; Yang, Hao; ...

2014-10-15

In this paper, we demonstrate a method to achieve high efficiency phase contrast imaging in aberration corrected scanning transmission electron microscopy (STEM) with a pixelated detector. The pixelated detector is used to record the Ronchigram as a function of probe position which is then analyzed with ptychography. Ptychography has previously been used to provide super-resolution beyond the diffraction limit of the optics, alongside numerically correcting for spherical aberration. Here we rely on a hardware aberration corrector to eliminate aberrations, but use the pixelated detector data set to utilize the largest possible volume of Fourier space to create high efficiency phasemore » contrast images. The use of ptychography to diagnose the effects of chromatic aberration is also demonstrated. In conclusion, the four dimensional dataset is used to compare different bright field detector configurations from the same scan for a sample of bilayer graphene. Our method of high efficiency ptychography produces the clearest images, while annular bright field produces almost no contrast for an in-focus aberration-corrected probe.« less

Biological nitrification/denitrification of high sodium nitrite (navy shipyard) wastewater.

PubMed

Kamath, S; Sabatini, D A; Canter, L W

1991-01-01

In the hydroblasting of ships' boiler tubes, a wastewater high in nitrite (as high as 1200 mg litre(-1)) is produced by the US Navy. This research has evaluated the use of a suspended-growth biological system to treat this wastewater by denitrification. Two biological treatment configurations were evaluated (direct denitrification versus nitrification/denitrification) with nitrification/denitrification producing better nitrite removal efficiencies (54 to 62% versus 40%, respectively). The introduction of metals (cadmium, chromium, lead, copper and iron) in concentrations typical for this wastewater did not inhibit the nitrite removal efficiencies. The influent metal concentrations ranged from 0.02 mg litre(-1) for cadmium to 22 mg litre(-1) for iron and the metal removal efficiencies ranged from 4.8% for cadmium to 50% for copper. Increasing sludge age resulted in improved nitrite removal efficiencies (52%, 57% and 74% for sludge ages of 4, 6 and 8 days, respectively). The resulting biokinetic constants were similar to those reported by others for lower influent concentrations of nitrite or nitrate (Ygs=0.02 mg/mg; Ygn=0.16 mg/mg; Yb=0.8 mg/mg; and b=0.006 h(-1)).

Characterization of Quantum Efficiency and Robustness of Cesium-Based Photocathodes

DTIC Science & Technology

2010-01-01

photocathodes produce picosecond-pulsed, high- current electron beams for photoinjection applications like free electron lasers . In photoinjectors, a...pulsed drive laser incident on the photocathode causes photoemission of short, dense bunches of electrons, which are then accelerated into a...relativistic, high quality beam. Future free electron lasers demand reliable photocathodes with long-lived quantum efficiency at suitable drive laser

Magnetic Force Switches for Magnetic Fluid Micromixing

NASA Astrophysics Data System (ADS)

Wei, Zung-Hang; Lee, Chiun-Peng; Lai, Mei-Feng

2010-01-01

A magnetic fluid micromixer with energy-saving magnetic force switches that can manipulate the magnetic fluid flow is proposed. The micromixer of high mixing efficiency uses single-domain micro magnets that have strong magnetic anisotropy to produce the magnetic force for the mixing. By altering the magnetization directions of the magnets that have different aspect ratios and coercivities, open and closed magnetic fluxes can be produced around each magnet cluster. For open magnetic flux, the mixing efficiency is numerically found to increase with the saturation magnetization of the magnets. On the contrary, the magnet clusters barely affects the mixing efficiency in the case of closed magnetic flux. Due to the different magnetic forces produced in open and closed magnetic fluxes, the magnetic fluid mixing can be switched on and off.

Advances of zeolite based membrane for hydrogen production via water gas shift reaction

NASA Astrophysics Data System (ADS)

Makertihartha, I. G. B. N.; Zunita, M.; Rizki, Z.; Dharmawijaya, P. T.

2017-07-01

Hydrogen is considered as a promising energy vector which can be obtained from various renewable sources. However, an efficient hydrogen production technology is still challenging. One technology to produce hydrogen with very high capacity with low cost is through water gas shift (WGS) reaction. Water gas shift reaction is an equilibrium reaction that produces hydrogen from syngas mixture by the introduction of steam. Conventional WGS reaction employs two or more reactors in series with inter-cooling to maximize conversion for a given volume of catalyst. Membrane reactor as new technology can cope several drawbacks of conventional reactor by removing reaction product and the reaction will favour towards product formation. Zeolite has properties namely high temperature, chemical resistant, and low price makes it suitable for membrane reactor applications. Moreover, it has been employed for years as hydrogen selective layer. This review paper is focusing on the development of membrane reactor for efficient water gas shift reaction to produce high purity hydrogen and carbon dioxide. Development of membrane reactor is discussed further related to its modification towards efficient reaction and separation from WGS reaction mixture. Moreover, zeolite framework suitable for WGS membrane reactor will be discussed more deeply.

Laser amplifier chain

DOEpatents

Hackel, Richard P.

1992-01-01

A laser amplifier chain has a plurality of laser amplifiers arranged in a chain to sequentially amplify a low-power signal beam to produce a significantly higher-power output beam. Overall efficiency of such a chain is improved if high-gain, low efficiency amplifiers are placed on the upstream side of the chain where only a very small fraction of the total pumped power is received by the chain and low-gain, high-efficiency amplifiers are placed on the downstream side where a majority of pumping energy is received by the chain.

High Efficiency Solar Integrated Roof Membrane Product

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

Partyka, Eric; Shenoy, Anil

2013-05-15

This project was designed to address the Solar Energy Technology Program objective, to develop new methods to integrate photovoltaic (PV) cells or modules within a building-integrated photovoltaic (BIPV) application that will result in lower installed cost as well as higher efficiencies of the encapsulated/embedded PV module. The technology assessment and development focused on the evaluation and identification of manufacturing technologies and equipment capable of producing such low-cost, high-efficiency, flexible BIPV solar cells on single-ply roofing membranes.

Guayule (Parthenium argentatum)pyrolysis and analysis by PY-GC/MS

USDA-ARS?s Scientific Manuscript database

Economic and sustainable biofuel production requires high process efficiency. The choice of biomass and the conversion technology employed to produce renewable fuels determines the product yields, fuel quality and consequently the process efficiency. Guayule, a perennial shrub native to the southwes...

Semirational Approach for Ultrahigh Poly(3-hydroxybutyrate) Accumulation in Escherichia coli by Combining One-Step Library Construction and High-Throughput Screening.

PubMed

Li, Teng; Ye, Jianwen; Shen, Rui; Zong, Yeqing; Zhao, Xuejin; Lou, Chunbo; Chen, Guo-Qiang

2016-11-18

As a product of a multistep enzymatic reaction, accumulation of poly(3-hydroxybutyrate) (PHB) in Escherichia coli (E. coli) can be achieved by overexpression of the PHB synthesis pathway from a native producer involving three genes phbC, phbA, and phbB. Pathway optimization by adjusting expression levels of the three genes can influence properties of the final product. Here, we reported a semirational approach for highly efficient PHB pathway optimization in E. coli based on a phbCAB operon cloned from the native producer Ralstonia entropha (R. entropha). Rationally designed ribosomal binding site (RBS) libraries with defined strengths for each of the three genes were constructed based on high or low copy number plasmids in a one-pot reaction by an oligo-linker mediated assembly (OLMA) method. Strains with desired properties were evaluated and selected by three different methodologies, including visual selection, high-throughput screening, and detailed in-depth analysis. Applying this approach, strains accumulating 0%-92% PHB contents in cell dry weight (CDW) were achieved. PHB with various weight-average molecular weights (M w ) of 2.7-6.8 × 10 6 were also efficiently produced in relatively high contents. These results suggest that the semirational approach combining library design, construction, and proper screening is an efficient way to optimize PHB and other multienzyme pathways.

Economic feasibility of converting center pivot irrigation to subsurface drip irrigation

USDA-ARS?s Scientific Manuscript database

Advancements in irrigation technology have increased water use efficiency. However, producers can be reluctant to convert to a more efficient irrigation system when the initial investment costs are high. This study examines the economic feasibility of replacing low energy precision application (LEPA...

Analyzing Clonal Variation of Monoclonal Antibody-Producing CHO Cell Lines Using an In Silico Metabolomic Platform

PubMed Central

Ghorbaniaghdam, Atefeh; Chen, Jingkui; Henry, Olivier; Jolicoeur, Mario

2014-01-01

Monoclonal antibody producing Chinese hamster ovary (CHO) cells have been shown to undergo metabolic changes when engineered to produce high titers of recombinant proteins. In this work, we have studied the distinct metabolism of CHO cell clones harboring an efficient inducible expression system, based on the cumate gene switch, and displaying different expression levels, high and low productivities, compared to that of the parental cells from which they were derived. A kinetic model for CHO cell metabolism was further developed to include metabolic regulation. Model calibration was performed using intracellular and extracellular metabolite profiles obtained from shake flask batch cultures. Model simulations of intracellular fluxes and ratios known as biomarkers revealed significant changes correlated with clonal variation but not to the recombinant protein expression level. Metabolic flux distribution mostly differs in the reactions involving pyruvate metabolism, with an increased net flux of pyruvate into the tricarboxylic acid (TCA) cycle in the high-producer clone, either being induced or non-induced with cumate. More specifically, CHO cell metabolism in this clone was characterized by an efficient utilization of glucose and a high pyruvate dehydrogenase flux. Moreover, the high-producer clone shows a high rate of anaplerosis from pyruvate to oxaloacetate, through pyruvate carboxylase and from glutamate to α-ketoglutarate, through glutamate dehydrogenase, and a reduced rate of cataplerosis from malate to pyruvate, through malic enzyme. Indeed, the increase of flux through pyruvate carboxylase was not driven by an increased anabolic demand. It is in fact linked to an increase of the TCA cycle global flux, which allows better regulation of higher redox and more efficient metabolic states. To the best of our knowledge, this is the first time a dynamic in silico platform is proposed to analyze and compare the metabolomic behavior of different CHO clones. PMID:24632968

An efficient and highly stereoselective synthesis of new P-chiral 1,5-diphosphanylferrocene ligands and their use in enantioselective hydrogenation.

PubMed

Chen, Weiping; Roberts, J Stanley M; Whittall, John; Steiner, Alexander

2006-07-21

An efficient and highly stereoselective synthesis of P-chiral 1,5-diphosphanylferrocene ligands has been developed, and the introduction of P-chirality in ferrocene-based phosphine ligands enhances the enantioselective discrimination produced by the corresponding catalyst when matching of the planar chirality, the chirality at carbon and the chirality at phosphorus occurs.

Outstanding adsorption performance of high aspect ratio and super-hydrophobic carbon nanotubes for oil removal.

PubMed

Kayvani Fard, Ahmad; Mckay, Gordon; Manawi, Yehia; Malaibari, Zuhair; Hussien, Muataz A

2016-12-01

Oil removal from water is a highly important area due to the large production rate of emulsified oil in water, which is considered one of the major pollutants, having a negative effect on human health, environment and wildlife. In this study, we have reported the application of high quality carbon nanotube bundles produced by an injected vertical chemical vapor deposition (IV-CVD) reactor for oil removal. High quality, bundles, super hydrophobic, and high aspect ratio carbon nanotubes were produced. The average diameters of the produced CNTs ranged from 20 to 50 nm while their lengths ranged from 300 to 500 μm. Two types of CNTs namely, P-CNTs and C-CNTs, (Produced CNTs from the IV-CVD reactor and commercial CNTs) were used for oil removal from water. For the first time, thermogravimetric analysis (TGA) was conducted to measure maximum oil uptake using CNT and it was found that P-CNT can take oil up to 17 times their weight. The effect of adsorbent dosage, contact time, and agitation speed were examined on the oil spill clean-up efficiency using batch sorption experiments. Higher efficiency with almost 97% removal was achieved using P-CNTs compared to 87% removal using C-CNTs. Copyright © 2016 Elsevier Ltd. All rights reserved.

Thermoelectric Power Generation System for Future Hybrid Vehicles Using Hot Exhaust Gas

NASA Astrophysics Data System (ADS)

Kim, Sun-Kook; Won, Byeong-Cheol; Rhi, Seok-Ho; Kim, Shi-Ho; Yoo, Jeong-Ho; Jang, Ju-Chan

2011-05-01

The present experimental and computational study investigates a new exhaust gas waste heat recovery system for hybrid vehicles, using a thermoelectric module (TEM) and heat pipes to produce electric power. It proposes a new thermoelectric generation (TEG) system, working with heat pipes to produce electricity from a limited hot surface area. The current TEG system is directly connected to the exhaust pipe, and the amount of electricity generated by the TEMs is directly proportional to their heated area. Current exhaust pipes fail to offer a sufficiently large hot surface area for the high-efficiency waste heat recovery required. To overcome this, a new TEG system has been designed to have an enlarged hot surface area by the addition of ten heat pipes, which act as highly efficient heat transfer devices and can transmit the heat to many TEMs. As designed, this new waste heat recovery system produces a maximum 350 W when the hot exhaust gas heats the evaporator surface of the heat pipe to 170°C; this promises great possibilities for application of this technology in future energy-efficient hybrid vehicles.

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

Wierer, Jonathan J.; Tsao, Jeffrey Y.; Sizov, Dmitry S.

Solid-state lighting (SSL) is now the most efficient source of high color quality white light ever created. Nevertheless, the blue InGaN light-emitting diodes (LEDs) that are the light engine of SSL still have significant performance limitations. Foremost among these is the decrease in efficiency at high input current densities widely known as “efficiency droop.” Efficiency droop limits input power densities, contrary to the desire to produce more photons per unit LED chip area and to make SSL more affordable. Pending a solution to efficiency droop, an alternative device could be a blue laser diode (LD). LDs, operated in stimulated emission,more » can have high efficiencies at much higher input power densities than LEDs can. In this article, LEDs and LDs for future SSL are explored by comparing: their current state-of-the-art input-power-density-dependent power-conversion efficiencies; potential improvements both in their peak power-conversion efficiencies and in the input power densities at which those efficiencies peak; and their economics for practical SSL.« less

High-power and highly efficient diode-cladding-pumped Ho3+-doped silica fiber lasers.

PubMed

Jackson, Stuart D; Bugge, Frank; Erbert, Götz

2007-11-15

We demonstrate high-power operation from a singly Ho3+-doped silica fiber laser that is cladding pumped directly with diode lasers operating at 1150 nm. Internal slope efficiencies approaching the Stokes limit were produced, and the maximum output power was 2.2W. This result was achieved using a low Ho3+-ion concentration and La3+-ion codoping, which together limit the transfer of energy between excited Ho3+ ions.

Enhanced cellulase producing mutants developed from heterokaryotic Aspergillus strain.

PubMed

Kaur, Baljit; Oberoi, H S; Chadha, B S

2014-03-01

A heterokaryon 28, derived through protoplast fusion between Aspergillus nidulans and Aspergillus tubingensis (Dal8), was subjected cyclic mutagenesis followed by selection on increasing levels of 2-deoxy glucose (2-DG) as selection marker. The derived deregulated cellulase hyper producing mutant '64', when compared to fusant 28, produced 9.83, 7.8, 3.2, 4.2 and 19.74 folds higher endoglucanase, β-glucosidase, cellobiohydrolase, FPase and xylanase, respectively, under shake cultures. The sequence analysis of PCR amplified β-glucosidase gene from wild and mutant showed nucleotide deletion/substitution. The mutants showed highly catalytic efficient β-glucosidase as evident from low Km and high Vmax values. The expression profiling through zymogram analysis also indicated towards over-expression of cellulases. The up/down regulated expressed proteins observed through SDS-PAGE were identified by Peptide mass fingerprinting The cellulase produced by mutants in conjunction with cellulase free xylanase derived from Thermomyces lanuginosus was used for efficient utilization of alkali treated rice straw for obtaining xylo-oligosaccharides and ethanol. Copyright © 2014 Elsevier Ltd. All rights reserved.

Metal-electrode-free Window-like Organic Solar Cells with p-Doped Carbon Nanotube Thin-film Electrodes

PubMed Central

Jeon, Il; Delacou, Clement; Kaskela, Antti; Kauppinen, Esko I.; Maruyama, Shigeo; Matsuo, Yutaka

2016-01-01

Organic solar cells are flexible and inexpensive, and expected to have a wide range of applications. Many transparent organic solar cells have been reported and their success hinges on full transparency and high power conversion efficiency. Recently, carbon nanotubes and graphene, which meet these criteria, have been used in transparent conductive electrodes. However, their use in top electrodes has been limited by mechanical difficulties in fabrication and doping. Here, expensive metal top electrodes were replaced with high-performance, easy-to-transfer, aerosol-synthesized carbon nanotubes to produce transparent organic solar cells. The carbon nanotubes were p-doped by two new methods: HNO3 doping via ‘sandwich transfer’, and MoOx thermal doping via ‘bridge transfer’. Although both of the doping methods improved the performance of the carbon nanotubes and the photovoltaic performance of devices, sandwich transfer, which gave a 4.1% power conversion efficiency, was slightly more effective than bridge transfer, which produced a power conversion efficiency of 3.4%. Applying a thinner carbon nanotube film with 90% transparency decreased the efficiency to 3.7%, which was still high. Overall, the transparent solar cells had an efficiency of around 50% that of non-transparent metal-based solar cells (7.8%). PMID:27527565

Metal-electrode-free Window-like Organic Solar Cells with p-Doped Carbon Nanotube Thin-film Electrodes.

PubMed

Jeon, Il; Delacou, Clement; Kaskela, Antti; Kauppinen, Esko I; Maruyama, Shigeo; Matsuo, Yutaka

2016-08-16

Organic solar cells are flexible and inexpensive, and expected to have a wide range of applications. Many transparent organic solar cells have been reported and their success hinges on full transparency and high power conversion efficiency. Recently, carbon nanotubes and graphene, which meet these criteria, have been used in transparent conductive electrodes. However, their use in top electrodes has been limited by mechanical difficulties in fabrication and doping. Here, expensive metal top electrodes were replaced with high-performance, easy-to-transfer, aerosol-synthesized carbon nanotubes to produce transparent organic solar cells. The carbon nanotubes were p-doped by two new methods: HNO3 doping via 'sandwich transfer', and MoOx thermal doping via 'bridge transfer'. Although both of the doping methods improved the performance of the carbon nanotubes and the photovoltaic performance of devices, sandwich transfer, which gave a 4.1% power conversion efficiency, was slightly more effective than bridge transfer, which produced a power conversion efficiency of 3.4%. Applying a thinner carbon nanotube film with 90% transparency decreased the efficiency to 3.7%, which was still high. Overall, the transparent solar cells had an efficiency of around 50% that of non-transparent metal-based solar cells (7.8%).

Engineering, construction, and operations in space

NASA Technical Reports Server (NTRS)

Johnson, Stewart W. (Editor); Wetzel, John P. (Editor)

1990-01-01

The century-old Mond process for carbonyl extraction of metals from ore shows great promise as an efficient low energy scheme for producing high-purity Fe, Ni, Cr, Mn, and Co from lunar or asteroidal feedstocks. Scenarios for winning oxygen from the lunar regolith can be enhanced by carbonyl processing of the metallic alloy by-products of such operations. The native metal content of asteroidal regoliths is even more suitable to carbonyl processing. High-purity, corrosion resistant Fe and Ni can be extracted from asteroidial feedstocks along with a Co-rich residue containing 0.5 percent platinum-group metals. The resulting gaseous metal carbonyl can produce a variety of end products using efficient vapor forming techniques.

High Energy Directly Pumped Ho:YLF Laser

NASA Technical Reports Server (NTRS)

Petros, Mulugeta; Yu, Ji-Rong; Singh, Upendra N.; Barnes, Norman P.

2000-01-01

The most commonly used crystal architecture to produce 2 micrometer laser is co-doping Ho and Tm into a single host crystal. In this method, the stored energy transfer from the Tm (3)F4 to the Ho (5)I7 manifold is not fast enough to warrant high efficiency for short pulse applications. By separating the Ho and the Tm ions and doping the Tm in YALO3 and the Ho in YLF, we were able to directly pump the Ho (5)I7 manifold with 1.94 micrometers. The Ho:YLF laser has produced 33 mJ at 2.062 micrometers with a quantum efficiency of 0.88. The performance of each laser will be presented.

Improving Best Air Conditioner Efficiency by 20-30% through a High Efficiency Fan and Diffuser Stage Coupled with an Evaporative Condenser Pre-Cooler

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

Parker, Danny S; Sherwin, John R; Raustad, Richard

2014-04-10

The Florida Solar Energy Center (FSEC) conducted a research project to improve the best residential air conditioner condenser technology currently available on the market by retrofitting a commercially-available unit with both a high efficiency fan system and an evaporative pre-cooler. The objective was to integrate these two concepts to achieve an ultra-efficient residential air conditioner design. The project produced a working prototype that was 30% more efficient compared to the best currently-available technologies; the peak the energy efficiency ratio (EER) was improved by 41%. Efficiency at the Air-Conditioning and Refrigeration Institute (ARI) standard B-condition which is used to estimate seasonalmore » energy efficiency ratio (SEER), was raised from a nominal 21 Btu/Wh to 32 Btu/Wh.« less

Absolute S- and P-plane polarization efficiencies for high frequency holographic gratings in the VUV

NASA Technical Reports Server (NTRS)

Caruso, A. J.; Woodgate, B. E.; Mount, G. H.

1981-01-01

High frequency plane gratings (3500 and 3600 gr/mm) have been holographically ruled and blazed for the VUV spectral region. All gratings were coated with 70 nm Al + 25 nm MgF2. Absolute unpolarized and S- and P-plane polarization efficiencies have been measured for the first and second orders in the 120- to 450-nm spectral region at 18.5 and 30 deg angles of deviation. For deep grooves, anomalous features are more pronounced for the P-plane polarization efficiency than for the S-plane polarization efficiency. Holographic gratings can be tailored to produce high polarization or low polarization in the VUV. For comparison, efficiencies and polarization of the best conventional high frequency gratings were also determined. Measurements show that scattered light is significantly lower for holographic gratings in the VUV when compared with the conventional gratings.

Widely tunable gas laser for remote sensing

NASA Technical Reports Server (NTRS)

Rothe, D. E.

1988-01-01

An advanced, highly efficient and reliable Rare-Gas Halide laser was developed. It employs the following: (1) novel prepulse techniques and impedance matching for efficient energy transfer; (2) magnetic switches for high reliability; (3) x-ray preionization for discharge uniformity and beam quality; and (4) an integrated gas flow loop for compactness. When operated as a XeCl laser, the unit produces 2 J per pulse with good beam uniformity. Optical pulse duration is 100 ns. Pulse repetition rate was tested up to 25 Hz. Efficiency is 3 percent.

Laser amplifier chain

DOEpatents

Hackel, R.P.

1992-10-20

A laser amplifier chain has a plurality of laser amplifiers arranged in a chain to sequentially amplify a low-power signal beam to produce a significantly higher-power output beam. Overall efficiency of such a chain is improved if high-gain, low efficiency amplifiers are placed on the upstream side of the chain where only a very small fraction of the total pumped power is received by the chain and low-gain, high-efficiency amplifiers are placed on the downstream side where a majority of pumping energy is received by the chain. 6 figs.

High-Efficiency Synthesis of Human α-Endorphin and Magainin in the Erythrocytes of Transgenic Mice: A Production System for Therapeutic Peptides

NASA Astrophysics Data System (ADS)

Sharma, Ajay; Khoury-Christianson, Anastasia M.; White, Steven P.; Dhanjal, Nirpal K.; Huang, Wen; Paulhiac, Clara; Friedman, Eric J.; Manjula, Belur N.; Kumar, Ramesh

1994-09-01

Chemical synthesis of peptides, though feasible, is hindered by considerations of cost, purity, and efficiency of synthesizing longer chains. Here we describe a transgenic system for producing peptides of therapeutic interest as fusion proteins at low cost and high purity. Transgenic hemoglobin expression technology using the locus control region was employed to produce fusion hemoglobins in the erythrocytes of mice. The fusion hemoglobin contains the desired peptide as an extension at the C end of human α-globin. A protein cleavage site is inserted between the C end of the α-globin chain and the N-terminal residue of the desired peptide. The peptide is recovered after cleavage of the fusion protein with enzymes that recognize this cleavage signal as their substrate. Due to the selective compartmentalization of hemoglobin in the erythrocytes, purification of the fusion hemoglobin is easy and efficient. Because of its compact and highly ordered structure, the internal sites of hemoglobin are resistant to protease digestion and the desired peptide is efficiently released and recovered. The applicability of this approach was established by producing a 16-mer α-endorphin peptide and a 26-mer magainin peptide in transgenic mice. Transgenic animals and their progeny expressing these fusion proteins remain healthy, even when the fusion protein is expressed at >25% of the total hemoglobin in the erythrocytes. Additional applications and potential improvements of this methodology are discussed.

High efficiency x-ray nanofocusing by the blazed stacking of binary zone plates

NASA Astrophysics Data System (ADS)

Mohacsi, I.; Karvinen, P.; Vartiainen, I.; Diaz, A.; Somogyi, A.; Kewish, C. M.; Mercere, P.; David, C.

2013-09-01

The focusing efficiency of binary Fresnel zone plate lenses is fundamentally limited and higher efficiency requires a multi step lens profile. To overcome the manufacturing problems of high resolution and high efficiency multistep zone plates, we investigate the concept of stacking two different binary zone plates in each other's optical near-field. We use a coarse zone plate with π phase shift and a double density fine zone plate with π/2 phase shift to produce an effective 4- step profile. Using a compact experimental setup with piezo actuators for alignment, we demonstrated 47.1% focusing efficiency at 6.5 keV using a pair of 500 μm diameter and 200 nm smallest zone width. Furthermore, we present a spatially resolved characterization method using multiple diffraction orders to identify manufacturing errors, alignment errors and pattern distortions and their effect on diffraction efficiency.

Communication—Electrolysis at High Efficiency with Remarkable Hydrogen Production Rates

DOE PAGES

Wood, Anthony; He, Hongpeng; Joia, Tahir; ...

2016-01-20

Solid Oxide Electrolysis (SOE) can be used to produce hydrogen with very high efficiencies at remarkable hydrogen production rates. Through microstructural and compositional modification, conventional low cost Solid Oxide Fuel Cell (SOFC) materials have been used to create a Solid Oxide Electrolysis Cell (SOEC) that can achieve remarkable current density at cell voltages allowing higher conversion efficiency than current commercial electrolysers. Current densities in excess of 6 A/cm2 have been achieved at 800°C with a cell voltage of < 1.67 V. This cell shows a more than 3-fold increase in hydrogen production rate at higher efficiency than established commercial electrolysers.

Rapid one-step recombinational cloning

PubMed Central

Fu, Changlin; Wehr, Daniel R.; Edwards, Janice; Hauge, Brian

2008-01-01

As an increasing number of genes and open reading frames of unknown function are discovered, expression of the encoded proteins is critical toward establishing function. Accordingly, there is an increased need for highly efficient, high-fidelity methods for directional cloning. Among the available methods, site-specific recombination-based cloning techniques, which eliminate the use of restriction endonucleases and ligase, have been widely used for high-throughput (HTP) procedures. We have developed a recombination cloning method, which uses truncated recombination sites to clone PCR products directly into destination/expression vectors, thereby bypassing the requirement for first producing an entry clone. Cloning efficiencies in excess of 80% are obtained providing a highly efficient method for directional HTP cloning. PMID:18424799

Increasing Stabilized Performance Of Amorphous Silicon Based Devices Produced By Highly Hydrogen Diluted Lower Temperature Plasma Deposition.

DOEpatents

Li, Yaun-Min; Bennett, Murray S.; Yang, Liyou

1999-08-24

High quality, stable photovoltaic and electronic amorphous silicon devices which effectively resist light-induced degradation and current-induced degradation, are produced by a special plasma deposition process. Powerful, efficient single and multi-junction solar cells with high open circuit voltages and fill factors and with wider bandgaps, can be economically fabricated by the special plasma deposition process. The preferred process includes relatively low temperature, high pressure, glow discharge of silane in the presence of a high concentration of hydrogen gas.

Increased Stabilized Performance Of Amorphous Silicon Based Devices Produced By Highly Hydrogen Diluted Lower Temperature Plasma Deposition.

DOEpatents

Li, Yaun-Min; Bennett, Murray S.; Yang, Liyou

1997-07-08

High quality, stable photovoltaic and electronic amorphous silicon devices which effectively resist light-induced degradation and current-induced degradation, are produced by a special plasma deposition process. Powerful, efficient single and multi-junction solar cells with high open circuit voltages and fill factors and with wider bandgaps, can be economically fabricated by the special plasma deposition process. The preferred process includes relatively low temperature, high pressure, glow discharge of silane in the presence of a high concentration of hydrogen gas.

Refractory oxide hosts for a high power, broadly tunable laser with high quantum efficiency and method of making same

DOEpatents

Chen, Yok; Gonzalez, Roberto

1986-01-01

Refractory oxide crystals having high-quantum efficiency and high thermal stability for use as broadly tunable laser host materials. The crystals are formed by removing hydrogen from a single crystal of the oxide material to a level below about 10.sup.12 protons per cm.sup.3 and subsequently thermochemically reducing the oxygen content of the crystal to form sufficient oxygen anion vacancies so that short-lived F.sup.+ luminescence is produced when the crystal is optically excited.

Refractory oxide hosts for a high power, broadly tunable laser with high quantum efficiency and method of making same

DOEpatents

Chen, Yok; Gonzalez, R.

1985-07-03

Refractory oxide crystals having high-quantum efficiency and high thermal stability for use as broadly tunable laser host materials. The crystals are formed by removing hydrogen from a single crystal of the oxide material to a level below about 10/sup 12/ protons per cm/sup 3/ and subsequently thermochemically reducing the oxygen content of the crystal to form sufficient oxygen anion vacancies so that short-lived F/sup +/ luminescence is produced when the crystal is optically excited.

Improving real-time efficiency of case-based reasoning for medical diagnosis.

PubMed

Park, Yoon-Joo

2014-01-01

Conventional case-based reasoning (CBR) does not perform efficiently for high volume dataset because of case-retrieval time. Some previous researches overcome this problem by clustering a case-base into several small groups, and retrieve neighbors within a corresponding group to a target case. However, this approach generally produces less accurate predictive performances than the conventional CBR. This paper suggests a new case-based reasoning method called the Clustering-Merging CBR (CM-CBR) which produces similar level of predictive performances than the conventional CBR with spending significantly less computational cost.

Surface nanodroplets for highly efficient liquid-liquid microextraction

NASA Astrophysics Data System (ADS)

Li, Miaosi; Lu, Ziyang; Yu, Haitao; Zhang, Xuehua

2016-11-01

Nanoscale droplets on a substrate are an essential element for a wide range of applications, such as laboratory-on-chip devices, simple and highly efficient miniaturized reactors for concentrating products, high-throughput single-bacteria or single-biomolecular analysis, encapsulation, and high-resolution imaging techniques. The solvent exchange process is a simple bottom-up approach for producing droplets at solid-liquid interfaces that are only several tens to hundreds of nanometers in height, or a few femtoliters in volume Oil nanodroplets can be produced on a substrate by solvent exchange in which a good solvent of oil is displaced by a poor solvent. Our previous work has significantly advanced understanding of the principle of solvent exchange, and the droplet size can be well-controlled by several parameters, including flow rates, flow geometry, gravitational effect and composition of solutions. In this work, we studied the microextraction effect of surface nanodroplets. Oil nanodroplets have been demonstrated to provide highly-efficient liquid-liquid microextraction of hydrophobic solute in a highly diluted solution. This effect proved the feasibility of nanodroplets as a platform for preconcentrating compounds for in situ highly sensitive microanalysis without further separation. Also the long lifetime and temporal stability of surface nanodroplets allow for some long-term extraction process and extraction without addition of stabilisers.

A new mechanism for relativistic particle acceleration via wave-particle interaction

NASA Astrophysics Data System (ADS)

Lapenta, Giovanni; Markidis, Stefano; Marocchino, Alberto

2006-10-01

Often in laboratory, space and astrophysical plasma, high energy populations are observed. Two puzzling factors still defy our understanding. First, such populations of high energy particles produce power law distributions that are not only ubiquitous but also persistent in time. Such persistence is in direct contradiction to the H theorem that states the ineluctable transition of physical systems towards thermodynamic equilibrium, and ergo Maxwellian distributions. Second, such high energy populations are efficiently produced, much more efficiently than processes that we know can produce. A classic example of such a situation is cosmic rays where power alws extend up to tremendolus energy ranges. In the present work, we identify a new mechanism for particle acceleration via wave-particle interaction. The mechanism is peculiar to special relativity and has no classical equivalent. That explains why it is not observed in most simulation studies of plasma processes, based on classical physics. The mechanism is likely to be active in systems undergoing streaming instabilities and in particular shocked systems. The new mechanism can produce energy increases vastly superior to previously known mechanisms (such as Fermi acceleration) and can hold the promise of explaining at least some of the observed power laws.

High-efficiency (6 + 1) × 1 pump-signal combiner based on low-deformation and high-precision alignment fabrication

NASA Astrophysics Data System (ADS)

Zou, Shuzhen; Chen, Han; Yu, Haijuan; Sun, Jing; Zhao, Pengfei; Lin, Xuechun

2017-12-01

We demonstrate a new method for fabricating a (6 + 1) × 1 pump-signal combiner based on the reduction of signal fiber diameter by corrosion. This method avoids the mismatch loss of the splice between the signal fiber and the output fiber caused by the signal fiber taper processing. The optimum radius of the corroded signal fiber was calculated according to the analysis of the influence of the cladding thickness on the laser propagating in the fiber core. Besides, we also developed a two-step splicing method to complete the high-precision alignment between the signal fiber core and the output fiber core. A high-efficiency (6 + 1) × 1 pump-signal combiner was produced with an average pump power transmission efficiency of 98.0% and a signal power transmission efficiency of 97.7%, which is well suitable for application to high-power fiber laser system.

High oxygen condition facilitates the differentiation of mouse and human pluripotent stem cells into pancreatic progenitors and insulin-producing cells.

PubMed

Hakim, Farzana; Kaitsuka, Taku; Raeed, Jamiruddin Mohd; Wei, Fan-Yan; Shiraki, Nobuaki; Akagi, Tadayuki; Yokota, Takashi; Kume, Shoen; Tomizawa, Kazuhito

2014-04-04

Pluripotent stem cells have potential applications in regenerative medicine for diabetes. Differentiation of stem cells into insulin-producing cells has been achieved using various protocols. However, both the efficiency of the method and potency of differentiated cells are insufficient. Oxygen tension, the partial pressure of oxygen, has been shown to regulate the embryonic development of several organs, including pancreatic β-cells. In this study, we tried to establish an effective method for the differentiation of induced pluripotent stem cells (iPSCs) into insulin-producing cells by culturing under high oxygen (O2) conditions. Treatment with a high O2 condition in the early stage of differentiation increased insulin-positive cells at the terminus of differentiation. We found that a high O2 condition repressed Notch-dependent gene Hes1 expression and increased Ngn3 expression at the stage of pancreatic progenitors. This effect was caused by inhibition of hypoxia-inducible factor-1α protein level. Moreover, a high O2 condition activated Wnt signaling. Optimal stage-specific treatment with a high O2 condition resulted in a significant increase in insulin production in both mouse embryonic stem cells and human iPSCs and yielded populations containing up to 10% C-peptide-positive cells in human iPSCs. These results suggest that culturing in a high O2 condition at a specific stage is useful for the efficient generation of insulin-producing cells.

Development of Advanced Deposition Technology for Microcrystalline Si Based Solar Cells and Modules: Final Technical Report, 1 May 2002-31 July 2004

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

Li, Y. M.

2004-12-01

The key objective of this subcontract was to take the first steps to extend the radio-frequency plasma-enhanced chemical vapor deposition (RF-PECVD) manufacturing technology of Energy Photovoltaics, Inc. (EPV), to the promising field of a-Si/nc-Si solar cell fabrication by demonstrating ''proof-of-concept'' devices of good efficiencies that previously were believed to be unobtainable in single-chamber reactors owing to contamination problems. A complementary goal was to find a new high-rate deposition method that can conceivably be deployed in large PECVD-type reactors. We emphasize that our goal was not to produce 'champion' devices of near-record efficiencies, but rather, to achieve modestly high efficiencies usingmore » a far simpler (cheaper) system, via practical processing methods and materials. To directly attack issues in solar-cell fabrication at EPV, the nc-Si thin films were studied almost exclusively in the p-i-n device configuration (as absorbers or i-layers), not as stand-alone films. Highly efficient, p-i-n type, nc-Si-based solar cells are generally grown on expensive, laboratory superstrates, such as custom ZnO/glass of high texture (granular surface) and low absorption. Also standard was the use of a highly effective back-reflector ZnO/Ag, where the ZnO can be surface-textured for efficient diffuse reflection. The high-efficiency ''champion'' devices made by the PECVD methods were invariably prepared in sophisticated (i.e., expensive), multi-chamber, or at least load-locked deposition systems. The electrode utilization efficiency, defined as the surface-area ratio of the powered electrode to that of the substrates, was typically low at about one (1:1). To evaluate the true potential of nc-Si absorbers for cost-competitive, commercially viable manufacturing of large-area PV modules, we took a more down-to-earth approach, based on our proven production of a-Si PV modules by a massively parallel batch process in single-chamber RF-PECVD systems, to the study of nc-Si solar cells, with the aim of producing high-efficiency a-Si/nc-Si solar cells and sub-modules.« less

An organic surface modifier to produce a high work function transparent electrode for high performance polymer solar cells.

PubMed

Choi, Hyosung; Kim, Hak-Beom; Ko, Seo-Jin; Kim, Jin Young; Heeger, Alan J

2015-02-04

Modification of an ITO electrode with small-molecule organic surface modifier, 4-chloro-benzoic acid (CBA), via a simple spin-coating method produces a high-work-function electrode with high transparency and a hydrophobic surface. As an alternative to PEDOT:PSS, CBA modification achieves efficiency enhancement up to 8.5%, which is attributed to enhanced light absorption within the active layer and smooth hole transport from the active layer to the anode. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Statistical properties of proportional residual energy intake as a new measure of energetic efficiency.

PubMed

Zamani, Pouya

2017-08-01

Traditional ratio measures of efficiency, including feed conversion ratio (FCR), gross milk efficiency (GME), gross energy efficiency (GEE) and net energy efficiency (NEE) may have some statistical problems including high correlations with milk yield. Residual energy intake (REI) or residual feed intake (RFI) is another criterion, proposed to overcome the problems attributed to the traditional ratio criteria, but it does not account for production or intake levels. For example, the same REI value could be considerable for low producing and negligible for high producing cows. The aim of this study was to propose a new measure of efficiency to overcome the problems attributed to the previous criteria. A total of 1478 monthly records of 268 lactating Holstein cows were used for this study. In addition to FCR, GME, GEE, NEE and REI, a new criterion called proportional residual energy intake (PREI) was calculated as REI to net energy intake ratio and defined as proportion of net energy intake lost as REI. The PREI had an average of -0·02 and range of -0·36 to 0·27, meaning that the least efficient cow lost 0·27 of her net energy intake as REI, while the most efficient animal saved 0·36 of her net energy intake as less REI. Traditional ratio criteria (FCR, GME, GEE and NEE) had high correlations with milk and fat corrected milk yields (absolute values from 0·469 to 0·816), while the REI and PREI had low correlations (0·000 to 0·069) with milk production. The results showed that the traditional ratio criteria (FCR, GME, GEE and NEE) are highly influenced by production traits, while the REI and PREI are independent of production level. Moreover, the PREI adjusts the REI magnitude for intake level. It seems that the PREI could be considered as a worthwhile measure of efficiency for future studies.

Highly efficient exciplex formation via radical ion pair recombination in X-irradiated alkane solutions for luminophores with short fluorescence lifetimes.

PubMed

Melnikov, Anatoly R; Kalneus, Evgeny V; Korolev, Valeri V; Dranov, Igor G; Kruppa, Alexander I; Stass, Dmitri V

2014-08-01

X-irradiation of alkane solutions of N,N-dimethylaniline with various organic luminophores produces characteristic emission bands ascribed to the corresponding exciplexes. In contrast to optical generation, which requires diffusion-controlled quenching of excited states, an additional channel of exciplex formation via irreversible recombination of radical ion pairs is operative here, which produces exciplexes in solution with high efficiency even for p-terphenyl and diphenylacetylene having fluorescence decay times of 0.95 ns and 8 ps, respectively. The exciplex emission band is sensitive to an external magnetic field and exerts a very large observed magnetic field effect of up to 20%, the maximum possible value under the conditions of the described experiment.

Creep feeding nursing beef calves.

PubMed

Lardy, Gregory P; Maddock, Travis D

2007-03-01

Creep feeding can be used to increase calf weaning weights. However, the gain efficiency of free-choice, energy-based creep feeds is relatively poor. Generally, limit-feeding, high-protein creep feeds are more efficient, and gains may be similar to those produced by creep feeds offered free choice. Creep feeding can increase total organic matter intake and improve the overall energy status of the animal. Creep-fed calves tend to acclimate to the feedlot more smoothly than unsupplemented calves. Furthermore, provision of a high-starch creep feed may have a positive influence on subsequent carcass quality traits. Creep feeding can be applied to numerous environmental situations to maximize calf performance; however, beef cattle producers should consider their individual situations carefully before making the decision to creep feed.

Efficiency analysis of betavoltaic elements

NASA Astrophysics Data System (ADS)

Sachenko, A. V.; Shkrebtii, A. I.; Korkishko, R. M.; Kostylyov, V. P.; Kulish, M. R.; Sokolovskyi, I. O.

2015-09-01

The conversion of energy of electrons produced by a radioactive β-source into electricity in a Si and SiC p- n junctions is modeled. The features of the generation function that describes the electron-hole pair production by an electron flux and the emergence of a "dead layer" are discussed. The collection efficiency Q that describes the rate of electron-hole pair production by incident beta particles, is calculated taking into account the presence of the dead layer. It is shown that in the case of high-grade Si p- n junctions, the collection efficiency of electron-hole pairs created by a high-energy electrons flux (such as, e.g., Pm-147 beta flux) is close or equal to unity in a wide range of electron energies. For SiC p-n junctions, Q is near unity only for electrons with relatively low energies of about 5 keV (produced, e.g., by a tritium source) and decreases rapidly with further increase of electron energy. The conditions, under which the influence of the dead layer on the collection efficiency is negligible, are determined. The open-circuit voltage is calculated for realistic values of the minority carriers' diffusion coefficients and lifetimes in Si and SiC p- n junctions, irradiated by a high-energy electrons flux. Our calculations allow to estimate the attainable efficiency of betavoltaic elements.

An Earth-Abundant Catalyst-Based Seawater Photoelectrolysis System with 17.9% Solar-to-Hydrogen Efficiency.

PubMed

Hsu, Shao-Hui; Miao, Jianwei; Zhang, Liping; Gao, Jiajian; Wang, Hongming; Tao, Huabing; Hung, Sung-Fu; Vasileff, Anthony; Qiao, Shi Zhang; Liu, Bin

2018-05-01

The implementation of water splitting systems, powered by sustainable energy resources, appears to be an attractive strategy for producing high-purity H 2 in the absence of the release of carbon dioxide (CO 2 ). However, the high cost, impractical operating conditions, and unsatisfactory efficiency and stability of conventional methods restrain their large-scale development. Seawater covers 70% of the Earth's surface and is one of the most abundant natural resources on the planet. New research is looking into the possibility of using seawater to produce hydrogen through electrolysis and will provide remarkable insight into sustainable H 2 production, if successful. Here, guided by density functional theory (DFT) calculations to predict the selectivity of gas-evolving catalysts, a seawater-splitting device equipped with affordable state-of-the-art electrocatalysts composed of earth-abundant elements (Fe, Co, Ni, and Mo) is demonstrated. This device shows excellent durability and specific selectivity toward the oxygen evolution reaction in seawater with near 100% Faradaic efficiency for the production of H 2 and O 2 . Powered by a single commercial III-V triple-junction photovoltaic cell, the integrated system achieves spontaneous and efficient generation of high-purity H 2 and O 2 from seawater at neutral pH with a remarkable 17.9% solar-to-hydrogen efficiency. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

A novel high-efficiency stable atmospheric microwave plasma device for fluid processing based on ridged waveguide

NASA Astrophysics Data System (ADS)

Xiao, Wei; Huang, Kama; He, Jianbo; Wu, Ying

2017-09-01

The waveguide-based microwave plasma device is widely used to generate atmospheric plasma for some industrial applications. Nevertheless, the traditional tapered waveguide device has limited power efficiency and produces unstable plasma. A novel ridged waveguide with an oblique hole is proposed to produce microwave atmospheric plasma for fluid processing. By using the ridged waveguide, the microwave field can be well focused, which can sustain plasma at relatively low power. Besides, an oblique hole is used to decrease the power reflection and generate a stable plasma torch especially in the case of high flowing rates. Experiments have been performed with the air flowing rates ranging from 500 l h-1 to 1000 l h-1 and the microwave working frequency of 2.45 GHz. The results show that in comparison with the conventional tapered waveguide, this novel device can both sustain plasma at relative low power and increase the power transfer efficiency by 11% from microwave to plasma. Moreover, both devices are used to process the waste gas-CO and CH4. Significantly, the removal efficiency for CO and CH4 can be increased by 19.7% and 32% respectively in the ridged waveguide compared with the tapered waveguide. It demonstrates that the proposed device possesses a great potential in industrial applications because of its high efficiency and stable performance.

The Feeding Biomechanics and Dietary Ecology of Paranthropus boisei

PubMed Central

Smith, Amanda L.; Benazzi, Stefano; Ledogar, Justin A.; Tamvada, Kelli; Pryor Smith, Leslie C.; Weber, Gerhard W.; Spencer, Mark A.; Lucas, Peter W.; Michael, Shaji; Shekeban, Ali; Al-Fadhalah, Khaled; Almusallam, Abdulwahab S.; Dechow, Paul C.; Grosse, Ian R.; Ross, Callum F.; Madden, Richard H.; Richmond, Brian G.; Wright, Barth W.; Wang, Qian; Byron, Craig; Slice, Dennis E.; Wood, Sarah; Dzialo, Christine; Berthaume, Michael A.; Casteren, Adam Van; Strait, David S.

2015-01-01

The African Plio-Pleistocene hominins known as australopiths evolved derived craniodental features frequently interpreted as adaptations for feeding on either hard, or compliant/tough foods. Among australopiths, Paranthropus boisei is the most robust form, exhibiting traits traditionally hypothesized to produce high bite forces efficiently and strengthen the face against feeding stresses. However, recent mechanical analyses imply that P. boisei may not have been an efficient producer of bite force and that robust morphology in primates is not necessarily strong. Here we use an engineering method, finite element analysis, to show that the facial skeleton of P. boisei is structurally strong, exhibits a strain pattern different from that in chimpanzees (Pan troglodytes) and Australopithecus africanus, and efficiently produces high bite force. It has been suggested that P. boisei consumed a diet of compliant/tough foods like grass blades and sedge pith. However, the blunt occlusal topography of this and other species suggests that australopiths are adapted to consume hard foods, perhaps including grass and sedge seeds. A consideration of evolutionary trends in morphology relating to feeding mechanics suggests that food processing behaviors in gracile australopiths evidently were disrupted by environmental change, perhaps contributing to the eventual evolution of Homo and Paranthropus. PMID:25529240

Limits on the maximum attainable efficiency for solid-state lighting

NASA Astrophysics Data System (ADS)

Coltrin, Michael E.; Tsao, Jeffrey Y.; Ohno, Yoshi

2008-03-01

Artificial lighting for general illumination purposes accounts for over 8% of global primary energy consumption. However, the traditional lighting technologies in use today, i.e., incandescent, fluorescent, and high-intensity discharge lamps, are not very efficient, with less than about 25% of the input power being converted to useful light. Solid-state lighting is a rapidly evolving, emerging technology whose efficiency of conversion of electricity to visible white light is likely to approach 50% within the next years. This efficiency is significantly higher than that of traditional lighting technologies, with the potential to enable a marked reduction in the rate of world energy consumption. There is no fundamental physical reason why efficiencies well beyond 50% could not be achieved, which could enable even greater world energy savings. The maximum achievable luminous efficacy for a solid-state lighting source depends on many different physical parameters, for example the color rendering quality that is required, the architecture employed to produce the component light colors that are mixed to produce white, and the efficiency of light sources producing each color component. In this article, we discuss in some detail several approaches to solid-state lighting and the maximum luminous efficacy that could be attained, given various constraints such as those listed above.

Improving Plant Nitrogen Use Efficiency through Alteration of Amino Acid Transport Processes1[OPEN

PubMed Central

Perchlik, Molly

2017-01-01

Improving the efficiency of nitrogen (N) uptake and utilization in plants could potentially increase crop yields while reducing N fertilization and, subsequently, environmental pollution. Within most plants, N is transported primarily as amino acids. In this study, pea (Pisum sativum) plants overexpressing AMINO ACID PERMEASE1 (AAP1) were used to determine if and how genetic manipulation of amino acid transport from source to sink affects plant N use efficiency. The modified plants were grown under low, moderate, or high N fertilization regimes. The results showed that, independent of the N nutrition, the engineered plants allocate more N via the vasculature to the shoot and seeds and produce more biomass and higher seed yields than wild-type plants. Dependent on the amount of N supplied, the AAP1-overexpressing plants displayed improved N uptake or utilization efficiency, or a combination of the two. They also showed significantly increased N use efficiency in N-deficient as well as in N-rich soils and, impressively, required half the amount of N to produce as many fruits and seeds as control plants. Together, these data support that engineering N allocation from source to sink presents an effective strategy to produce crop plants with improved productivity as well as N use efficiency in a range of N environments. PMID:28733388

Bilayer graphene phonovoltaic-FET: In situ phonon recycling

NASA Astrophysics Data System (ADS)

Melnick, Corey; Kaviany, Massoud

2017-11-01

A new heat harvester, the phonovoltaic (pV) cell, was recently proposed. The device converts optical phonons into power before they become heat. Due to the low entropy of a typical hot optical phonon population, the phonovoltaic can operate at high fractions of the Carnot limit and harvest heat more efficiently than conventional heat harvesting technologies such as the thermoelectric generator. Previously, the optical phonon source was presumed to produce optical phonons with a single polarization and momentum. Here, we examine a realistic optical phonon source in a potential pV application and the effects this has on pV operation. Supplementing this work is our investigation of bilayer graphene as a new pV material. Our ab initio calculations show that bilayer graphene has a figure of merit exceeding 0.9, well above previously investigated materials. This allows a room-temperature pV to recycle 65% of a highly nonequilibrium, minimum entropy population of phonons. However, full-band Monte Carlo simulations of the electron and phonon dynamics in a bilayer graphene field-effect transistor (FET) show that the optical phonons emitted by field-accelerated electrons can only be recycled in situ with an efficiency of 50%, and this efficiency falls as the field strength grows. Still, an appropriately designed FET-pV can recycle the phonons produced therein in situ with a much higher efficiency than a thermoelectric generator can harvest heat produced by a FET ex situ.

Laser doping of boron-doped Si paste for high-efficiency silicon solar cells

NASA Astrophysics Data System (ADS)

Tomizawa, Yuka; Imamura, Tetsuya; Soeda, Masaya; Ikeda, Yoshinori; Shiro, Takashi

2015-08-01

Boron laser doping (LD) is a promising technology for high-efficiency solar cells such as p-type passivated locally diffused solar cells and n-type Si-wafer-based solar cells. We produced a printable phosphorus- or boron-doped Si paste (NanoGram® Si paste/ink) for use as a diffuser in the LD process. We used the boron LD process to fabricate high-efficiency passivated emitter and rear locally diffused (PERL) solar cells. PERL solar cells on Czochralski Si (Cz-Si) wafers yielded a maximum efficiency of 19.7%, whereas the efficiency of a reference cell was 18.5%. Fill factors above 79% and open circuit voltages above 655 mV were measured. We found that the boron-doped area effectively performs as a local boron back surface field (BSF). The characteristics of the solar cell formed using NanoGram® Si paste/ink were better than those of the reference cell.

A balanced microbiota efficiently produces methane in a novel high-rate horizontal anaerobic reactor for the treatment of swine wastewater.

PubMed

Duda, Rose Maria; da Silva Vantini, Juliana; Martins, Larissa Scattolin; de Mello Varani, Alessandro; Lemos, Manoel Victor Franco; Ferro, Maria Inês Tiraboschi; de Oliveira, Roberto Alves

2015-12-01

A novel combination of structurally simple, high-rate horizontal anaerobic reactors installed in series was used to treat swine wastewater. The reactors maintained stable pH, alkalinity, and volatile acid levels. Removed chemical oxygen demand (COD) represented 68% of the total, and the average specific methane production was 0.30L CH4 (g removed CODtot)(-1). In addition, next-generation sequencing and quantitative real-time PCR analyses were used to explore the methane-producing Archaea and microbial diversity. At least 94% of the sludge diversity belong to the Bacteria and Archaea, indicating a good balance of microorganisms. Among the Bacteria the Proteobacteria, Bacteroidetes and Firmicutes were the most prevalent phyla. Interestingly, up to 12% of the sludge diversity belongs to methane-producing orders, such as Methanosarcinales, Methanobacteriales and Methanomicrobiales. In summary, this system can efficiently produce methane and this is the first time that horizontal anaerobic reactors have been evaluated for the treatment of swine wastewater. Copyright © 2015 Elsevier Ltd. All rights reserved.

Design of an organic redox mediator and optimization of an organic counter electrode for efficient transparent bifacial dye-sensitized solar cells.

PubMed

Li, Xiong; Ku, Zhiliang; Rong, Yaoguang; Liu, Guanghui; Liu, Linfeng; Liu, Tongfa; Hu, Min; Yang, Ying; Wang, Heng; Xu, Mi; Xiang, Peng; Han, Hongwei

2012-11-07

A new thiolate/disulfide mediator was designed and synthesized by employing DFT calculations as a guide. It possesses high transparency to visible light, a very attractive feature for bifacially active transparent DSCs that require a highly transparent counter electrode (CE). Compared to the reported and most promising thiolate/disulfide mediator T(-)/T(2), this new analogous mediator produced a major enhancement in open circuit potential (V(OC)) by about 40 mV and correspondingly a higher power conversion efficiency (η) for DSCs. Furthermore, a highly uniform and transparent (transmittance > 91%) poly(3,4-ethylenedioxythiophene) (PEDOT(BE)) CE was prepared and could efficiently catalyze the reduction of the disulfide. Based on the novel transparent redox couple and PEDOT(BE) CE, a new type of iodine-free and Pt-free transparent bifacial DSC was successfully fabricated. This new bifacial device could not only yield a promising front-illuminated η of 6.07%, but also produce an attractive η as high as 4.35% for rear-side irradiation, which exceeds the rear-illuminated η of 3.93% achieved for the same type of device, employing the dark-colored I(-)/I(3)(-) electrolyte.

High-efficiency photovoltaic cells

DOEpatents

Yang, H.T.; Zehr, S.W.

1982-06-21

High efficiency solar converters comprised of a two cell, non-lattice matched, monolithic stacked semiconductor configuration using optimum pairs of cells having bandgaps in the range 1.6 to 1.7 eV and 0.95 to 1.1 eV, and a method of fabrication thereof, are disclosed. The high band gap subcells are fabricated using metal organic chemical vapor deposition (MOCVD), liquid phase epitaxy (LPE) or molecular beam epitaxy (MBE) to produce the required AlGaAs layers of optimized composition, thickness and doping to produce high performance, heteroface homojunction devices. The low bandgap subcells are similarly fabricated from AlGa(As)Sb compositions by LPE, MBE or MOCVD. These subcells are then coupled to form a monolithic structure by an appropriate bonding technique which also forms the required transparent intercell ohmic contact (IOC) between the two subcells. Improved ohmic contacts to the high bandgap semiconductor structure can be formed by vacuum evaporating to suitable metal or semiconductor materials which react during laser annealing to form a low bandgap semiconductor which provides a low contact resistance structure.

High regression rate hybrid rocket fuel grains with helical port structures

NASA Astrophysics Data System (ADS)

Walker, Sean D.

Hybrid rockets are popular in the aerospace industry due to their storage safety, simplicity, and controllability during rocket motor burn. However, they produce fuel regression rates typically 25% lower than solid fuel motors of the same thrust level. These lowered regression rates produce unacceptably high oxidizer-to-fuel (O/F) ratios that produce a potential for motor instability, nozzle erosion, and reduced motor duty cycles. To achieve O/F ratios that produce acceptable combustion characteristics, traditional cylindrical fuel ports are fabricated with very long length-to-diameter ratios to increase the total burning area. These high aspect ratios produce further reduced fuel regression rate and thrust levels, poor volumetric efficiency, and a potential for lateral structural loading issues during high thrust burns. In place of traditional cylindrical fuel ports, it is proposed that by researching the effects of centrifugal flow patterns introduced by embedded helical fuel port structures, a significant increase in fuel regression rates can be observed. The benefits of increasing volumetric efficiencies by lengthening the internal flow path will also be observed. The mechanisms of this increased fuel regression rate are driven by enhancing surface skin friction and reducing the effect of boundary layer "blowing" to enhance convective heat transfer to the fuel surface. Preliminary results using additive manufacturing to fabricate hybrid rocket fuel grains from acrylonitrile-butadiene-styrene (ABS) with embedded helical fuel port structures have been obtained, with burn-rate amplifications up to 3.0x than that of cylindrical fuel ports.

Complete Protection against Pneumonic and Bubonic Plague after a Single Oral Vaccination

PubMed Central

Derbise, Anne; Hanada, Yuri; Khalifé, Manal; Carniel, Elisabeth; Demeure, Christian E.

2015-01-01

Background No efficient vaccine against plague is currently available. We previously showed that a genetically attenuated Yersinia pseudotuberculosis producing the Yersinia pestis F1 antigen was an efficient live oral vaccine against pneumonic plague. This candidate vaccine however failed to confer full protection against bubonic plague and did not produce F1 stably. Methodology/Principal Findings The caf operon encoding F1 was inserted into the chromosome of a genetically attenuated Y. pseudotuberculosis, yielding the VTnF1 strain, which stably produced the F1 capsule. Given orally to mice, VTnF1 persisted two weeks in the mouse gut and induced a high humoral response targeting both F1 and other Y. pestis antigens. The strong cellular response elicited was directed mostly against targets other than F1, but also against F1. It involved cells with a Th1—Th17 effector profile, producing IFNγ, IL-17, and IL-10. A single oral dose (108 CFU) of VTnF1 conferred 100% protection against pneumonic plague using a high-dose challenge (3,300 LD50) caused by the fully virulent Y. pestis CO92. Moreover, vaccination protected 100% of mice from bubonic plague caused by a challenge with 100 LD50 Y. pestis and 93% against a high-dose infection (10,000 LD50). Protection involved fast-acting mechanisms controlling Y. pestis spread out of the injection site, and the protection provided was long-lasting, with 93% and 50% of mice surviving bubonic and pneumonic plague respectively, six months after vaccination. Vaccinated mice also survived bubonic and pneumonic plague caused by a high-dose of non-encapsulated (F1-) Y. pestis. Significance VTnF1 is an easy-to-produce, genetically stable plague vaccine candidate, providing a highly efficient and long-lasting protection against both bubonic and pneumonic plague caused by wild type or un-encapsulated (F1-negative) Y. pestis. To our knowledge, VTnF1 is the only plague vaccine ever reported that could provide high and durable protection against the two forms of plague after a single oral administration. PMID:26473734

Complete Protection against Pneumonic and Bubonic Plague after a Single Oral Vaccination.

PubMed

Derbise, Anne; Hanada, Yuri; Khalifé, Manal; Carniel, Elisabeth; Demeure, Christian E

2015-01-01

No efficient vaccine against plague is currently available. We previously showed that a genetically attenuated Yersinia pseudotuberculosis producing the Yersinia pestis F1 antigen was an efficient live oral vaccine against pneumonic plague. This candidate vaccine however failed to confer full protection against bubonic plague and did not produce F1 stably. The caf operon encoding F1 was inserted into the chromosome of a genetically attenuated Y. pseudotuberculosis, yielding the VTnF1 strain, which stably produced the F1 capsule. Given orally to mice, VTnF1 persisted two weeks in the mouse gut and induced a high humoral response targeting both F1 and other Y. pestis antigens. The strong cellular response elicited was directed mostly against targets other than F1, but also against F1. It involved cells with a Th1-Th17 effector profile, producing IFNγ, IL-17, and IL-10. A single oral dose (108 CFU) of VTnF1 conferred 100% protection against pneumonic plague using a high-dose challenge (3,300 LD50) caused by the fully virulent Y. pestis CO92. Moreover, vaccination protected 100% of mice from bubonic plague caused by a challenge with 100 LD50 Y. pestis and 93% against a high-dose infection (10,000 LD50). Protection involved fast-acting mechanisms controlling Y. pestis spread out of the injection site, and the protection provided was long-lasting, with 93% and 50% of mice surviving bubonic and pneumonic plague respectively, six months after vaccination. Vaccinated mice also survived bubonic and pneumonic plague caused by a high-dose of non-encapsulated (F1-) Y. pestis. VTnF1 is an easy-to-produce, genetically stable plague vaccine candidate, providing a highly efficient and long-lasting protection against both bubonic and pneumonic plague caused by wild type or un-encapsulated (F1-negative) Y. pestis. To our knowledge, VTnF1 is the only plague vaccine ever reported that could provide high and durable protection against the two forms of plague after a single oral administration.

Algal sludge from Taihu Lake can be utilized to create novel PGPR-containing bio-organic fertilizers.

PubMed

Zhang, Miao; Li, Rong; Cao, Liangliang; Shi, Juanjuan; Liu, Hongjun; Huang, Yan; Shen, Qirong

2014-01-01

Large amounts of refloated algal sludge from Taihu Lake result in secondary environmental pollution due to annual refloatation. This study investigated the possibility to produce bio-organic fertilizer (BIO) using algal sludge as a solid-state fermentation (SSF) medium. Results showed that addition of algal sludge contributed to efficient SFF by a plant growth-promoting rhizobacteria (PGPR) strain SQR9 and improved the nutrient contents in the novel BIO. The optimum water content and initial inoculation size were 45% and 5%, respectively. After 6 days of SSF, the biomass of strain SQR9 was increased to a cell density of more than 5 × 10(7) CFU g(-1). Microcystins were rapidly degraded, and a high germination index value was observed. Plant growth experiments showed that the produced BIO efficiently promoted plant growth. Additional testing showed that the novel SSF process was also suitable for other PGPR strains. This study provides a novel way of high-value utilization of algal sludge from Taihu Lake by producing low-cost but high-quality BIOs. Copyright © 2013 Elsevier Ltd. All rights reserved.

Multi-Physics Modeling of Molten Salt Transport in Solid Oxide Membrane (SOM) Electrolysis and Recycling of Magnesium

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

Powell, Adam; Pati, Soobhankar

2012-03-11

Solid Oxide Membrane (SOM) Electrolysis is a new energy-efficient zero-emissions process for producing high-purity magnesium and high-purity oxygen directly from industrial-grade MgO. SOM Recycling combines SOM electrolysis with electrorefining, continuously and efficiently producing high-purity magnesium from low-purity partially oxidized scrap. In both processes, electrolysis and/or electrorefining take place in the crucible, where raw material is continuously fed into the molten salt electrolyte, producing magnesium vapor at the cathode and oxygen at the inert anode inside the SOM. This paper describes a three-dimensional multi-physics finite-element model of ionic current, fluid flow driven by argon bubbling and thermal buoyancy, and heat andmore » mass transport in the crucible. The model predicts the effects of stirring on the anode boundary layer and its time scale of formation, and the effect of natural convection at the outer wall. MOxST has developed this model as a tool for scale-up design of these closely-related processes.« less

Development of high-efficiency power amplifiers for PIP2 (Project X), Phase II

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

Raab, Frederick

The Fermi Lab PIP II (formerly Project X) accelerator will require the generation of over a megawatt of radio-frequency (RF) power at 325 and 650 MHz. This Phase-II SBIR grant developed techniques to generate this RF power efficienly. The basis of this approach is a system comprising high-efficiency RF power amplifiers, high-efficiency class-S modulators to maintain efficiency at all power levels, and low-loss power combiners. A digital signal processor adjusts signal parameters to obtain the maximum efficiency while producing a signal of the desired amplitude and phase. Components of 4-kW prototypes were designed, assembled, and tested. The 500-W modules producemore » signals at 325 MHz with an overall efficiency of 83 percent and signals at 650 MHz with an overall efficiency of 79 percent. This efficiency is nearly double that available from conventional techniques, which makes it possible to cut the power consumption nearly in half. The system is designed to be scalable to the multi-kilowatt level and can be adapted to other DoE applications.« less

Optically efficient InAsSb nanowires for silicon-based mid-wavelength infrared optoelectronics.

PubMed

Zhuang, Q D; Alradhi, H; Jin, Z M; Chen, X R; Shao, J; Chen, X; Sanchez, Ana M; Cao, Y C; Liu, J Y; Yates, P; Durose, K; Jin, C J

2017-03-10

InAsSb nanowires (NWs) with a high Sb content have potential in the fabrication of advanced silicon-based optoelectronics such as infrared photondetectors/emitters and highly sensitive phototransistors, as well as in the generation of renewable electricity. However, producing optically efficient InAsSb NWs with a high Sb content remains a challenge, and optical emission is limited to 4.0 μm due to the quality of the nanowires. Here, we report, for the first time, the success of high-quality and optically efficient InAsSb NWs enabling silicon-based optoelectronics operating in entirely mid-wavelength infrared. Pure zinc-blende InAsSb NWs were realized with efficient photoluminescence emission. We obtained room-temperature photoluminescence emission in InAs NWs and successfully extended the emission wavelength in InAsSb NWs to 5.1 μm. The realization of this optically efficient InAsSb NW material paves the way to realizing next-generation devices, combining advances in III-V semiconductors and silicon.

Efficient perovskite light-emitting diodes featuring nanometre-sized crystallites

NASA Astrophysics Data System (ADS)

Xiao, Zhengguo; Kerner, Ross A.; Zhao, Lianfeng; Tran, Nhu L.; Lee, Kyung Min; Koh, Tae-Wook; Scholes, Gregory D.; Rand, Barry P.

2017-01-01

Organic-inorganic hybrid perovskite materials are emerging as highly attractive semiconductors for use in optoelectronics. In addition to their use in photovoltaics, perovskites are promising for realizing light-emitting diodes (LEDs) due to their high colour purity, low non-radiative recombination rates and tunable bandgap. Here, we report highly efficient perovskite LEDs enabled through the formation of self-assembled, nanometre-sized crystallites. Large-group ammonium halides added to the perovskite precursor solution act as a surfactant that dramatically constrains the growth of 3D perovskite grains during film forming, producing crystallites with dimensions as small as 10 nm and film roughness of less than 1 nm. Coating these nanometre-sized perovskite grains with longer-chain organic cations yields highly efficient emitters, resulting in LEDs that operate with external quantum efficiencies of 10.4% for the methylammonium lead iodide system and 9.3% for the methylammonium lead bromide system, with significantly improved shelf and operational stability.

A high-efficiency thermoelectric converter for space applications

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

Metzger, J.D.; El-Genk, M.S.

1990-01-01

This paper presents a concept for using high-temperature superconducting materials in thermoelectric generators (SCTE) to produce electricity at conversion efficiencies approaching 50% of the Carrot efficiency. The SCTE generator is applicable to systems operating in temperature ranges of high-temperature superconducting materials and thus would be a low-grade converter. Operating in cryogenic temperature ranges provides the advantage of inherently increasing the limits of the Carrot efficiency. Potential applications are for systems operating in space where the ambient temperatures are in the cryogenic temperature range. The advantage of using high-temperature superconducting material in a thermoelectric converter is that it would significantly reducemore » or eliminate the Joule heating losses in a thermoelectric element. This paper investigates the system aspects and the material requirements of the SCTE converter concept, and presents a conceptual design and an application for a space power system.« less

A high-efficiency thermoelectric converter for space applications

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

Metzger, J.D.; El-Genk, M.S.

1990-12-31

This paper presents a concept for using high-temperature superconducting materials in thermoelectric generators (SCTE) to produce electricity at conversion efficiencies approaching 50% of the Carrot efficiency. The SCTE generator is applicable to systems operating in temperature ranges of high-temperature superconducting materials and thus would be a low-grade converter. Operating in cryogenic temperature ranges provides the advantage of inherently increasing the limits of the Carrot efficiency. Potential applications are for systems operating in space where the ambient temperatures are in the cryogenic temperature range. The advantage of using high-temperature superconducting material in a thermoelectric converter is that it would significantly reducemore » or eliminate the Joule heating losses in a thermoelectric element. This paper investigates the system aspects and the material requirements of the SCTE converter concept, and presents a conceptual design and an application for a space power system.« less

Kilohertz Pulse Repetition Frequency Slab Ti:sapphire Lasers with High Average Power (10 W)

NASA Astrophysics Data System (ADS)

Wadsworth, William J.; Coutts, David W.; Webb, Colin E.

1999-11-01

High-average-power broadband 780-nm slab Ti:sapphire lasers, pumped by a kilohertz pulse repetition frequency copper vapor laser (CVL), were demonstrated. These lasers are designed for damage-free power scaling when pumped by CVL s configured for maximum output power (of order 100 W) but with poor beam quality ( M 2 300 ). A simple Brewster-angled slab laser side pumped by a CVL produced 10-W average power (1.25-mJ pulses at 8 kHz) with 4.2-ns FWHM pulse duration at an absolute efficiency of 15% (68-W pump power). Thermal lensing in the Brewster slab laser resulted in multitransverse mode output, and pump absorption was limited to 72% by the maximum doping level for commercially available Ti:sapphire (0.25%). A slab laser with a multiply folded zigzag path was therefore designed and implemented that produced high-beam-quality (TEM 00 -mode) output when operated with cryogenic cooling and provided a longer absorption path for the pump. Excessive scattering of the Ti:sapphire beam at the crystal surfaces limited the efficiency of operation for the zigzag laser, but fluorescence diagnostic techniques, gain measurement, and modeling suggest that efficient power extraction ( 15 W TEM 00 , 23% efficiency) from this laser would be possible for crystals with an optical quality surface polish.

Modeling and experimental performance of an intermediate temperature reversible solid oxide cell for high-efficiency, distributed-scale electrical energy storage

NASA Astrophysics Data System (ADS)

Wendel, Christopher H.; Gao, Zhan; Barnett, Scott A.; Braun, Robert J.

2015-06-01

Electrical energy storage is expected to be a critical component of the future world energy system, performing load-leveling operations to enable increased penetration of renewable and distributed generation. Reversible solid oxide cells, operating sequentially between power-producing fuel cell mode and fuel-producing electrolysis mode, have the capability to provide highly efficient, scalable electricity storage. However, challenges ranging from cell performance and durability to system integration must be addressed before widespread adoption. One central challenge of the system design is establishing effective thermal management in the two distinct operating modes. This work leverages an operating strategy to use carbonaceous reactant species and operate at intermediate stack temperature (650 °C) to promote exothermic fuel-synthesis reactions that thermally self-sustain the electrolysis process. We present performance of a doped lanthanum-gallate (LSGM) electrolyte solid oxide cell that shows high efficiency in both operating modes at 650 °C. A physically based electrochemical model is calibrated to represent the cell performance and used to simulate roundtrip operation for conditions unique to these reversible systems. Design decisions related to system operation are evaluated using the cell model including current density, fuel and oxidant reactant compositions, and flow configuration. The analysis reveals tradeoffs between electrical efficiency, thermal management, energy density, and durability.

Efficient acceleration of neutral atoms in laser produced plasma

DOE PAGES

Dalui, M.; Trivikram, T. M.; Colgan, James Patrick; ...

2017-06-20

Recent advances in high-intensity laser-produced plasmas have demonstrated their potential as compact charge particle accelerators. Unlike conventional accelerators, transient quasi-static charge separation acceleration fields in laser produced plasmas are highly localized and orders of magnitude larger. Manipulating these ion accelerators, to convert the fast ions to neutral atoms with little change in momentum, transform these to a bright source of MeV atoms. The emittance of the neutral atom beam would be similar to that expected for an ion beam. Since intense laser-produced plasmas have been demonstrated to produce high-brightness-low-emittance beams, it is possible to envisage generation of high-flux, low-emittance, highmore » energy neutral atom beams in length scales of less than a millimeter. Here, we show a scheme where more than 80% of the fast ions are reduced to energetic neutral atoms and demonstrate the feasibility of a high energy neutral atom accelerator that could significantly impact applications in neutral atom lithography and diagnostics.« less

Low-Cost, High-Performance Cryocoolers for In-Situ Propellant Production

NASA Technical Reports Server (NTRS)

Martin, J. L.; Corey, J. A.; Peters, T. A.

1999-01-01

A key feature of many In-Situ Resource Utilization (ISRU) schemes is the production of rocket fuel and oxidizer from the Martian atmosphere. Many of the fuels under consideration will require cryogenic cooling for efficient long-term storage. Although significant research has been focused on the techniques for producing the fuels from Martian resources, little effort has been expended on the development of cryocoolers to efficiently liquefy these fuels. This paper describes the design of a pulse tube liquefier optimized for liquefying oxygen produced by an In-Situ Propellant Production (ISPP) plant on Mars.

Low-Cost High-Performance Cryocoolers for In-Situ Propellant Production

NASA Technical Reports Server (NTRS)

Martin, J. L.; Corey, J. A.; Peters, T. A.

1999-01-01

A key feature of many In-Situ Resource Utilization (ISRU) schemes is the production of rocket fuel and oxidizer from the Martian atmosphere. Many of the fuels under consideration will require cryogenic cooling for efficient long-term storage. Although significant research has been focused on the techniques for producing the fuels from Martian resources, little effort has been expended on the development of cryocoolers to efficiently liquefy these fuels. This paper describes the design of a pulse tube liquefier optimized for liquefying oxygen produced by an In-Situ Propellant Production (ISPP) plant on Mars.

Recovery of succinic acid produced by fermentation of a metabolically engineered Mannheimia succiniciproducens strain.

PubMed

Song, Hyohak; Huh, Yun Suk; Lee, Sang Yup; Hong, Won Hi; Hong, Yeon Ki

2007-12-01

There have recently been much advances in the production of succinic acid, an important four-carbon dicarboxylic acid for many industrial applications, by fermentation of several natural and engineered bacterial strains. Mannheimia succiniciproducens MBEL55E isolated from bovine rumen is able to produce succinic acid with high efficiency, but also produces acetic, formic and lactic acids just like other anaerobic succinic acid producers. We recently reported the development of an engineered M. succiniciproducens LPK7 strain which produces succinic acid as a major fermentation product while producing much reduced by-products. Having an improved succinic acid producer developed, it is equally important to develop a cost-effective downstream process for the recovery of succinic acid. In this paper, we report the development of a simpler and more efficient method for the recovery of succinic acid. For the recovery of succinic acid from the fermentation broth of LPK7 strain, a simple process composed of a single reactive extraction, vacuum distillation, and crystallization yielded highly purified succinic acid (greater than 99.5% purity, wt%) with a high yield of 67.05wt%. When the same recovery process or even multiple reactive extraction steps were applied to the fermentation broth of MBEL55E, lower purity and yield of succinic acid were obtained. These results suggest that succinic acid can be purified in a cost-effective manner by using the fermentation broth of engineered LPK7 strain, showing the importance of integrating the strain development, fermentation and downstream process for optimizing the whole processes for succinic acid production.

Processes for producing low cost, high efficiency silicon solar cells

DOEpatents

Rohatgi, Ajeet; Chen, Zhizhang; Doshi, Parag

1996-01-01

Processes which utilize rapid thermal processing (RTP) are provided for inexpensively producing high efficiency silicon solar cells. The RTP processes preserve minority carrier bulk lifetime .tau. and permit selective adjustment of the depth of the diffused regions, including emitter and back surface field (bsf), within the silicon substrate. Silicon solar cell efficiencies of 16.9% have been achieved. In a first RTP process, an RTP step is utilized to simultaneously diffuse phosphorus and aluminum into the front and back surfaces, respectively, of a silicon substrate. Moreover, an in situ controlled cooling procedure preserves the carrier bulk lifetime .tau. and permits selective adjustment of the depth of the diffused regions. In a second RTP process, both simultaneous diffusion of the phosphorus and aluminum as well as annealing of the front and back contacts are accomplished during the RTP step. In a third RTP process, the RTP step accomplishes simultaneous diffusion of the phosphorus and aluminum, annealing of the contacts, and annealing of a double-layer antireflection/passivation coating SiN/SiO.sub.x.

CRISPR-Cas9, a tool to efficiently increase the development of recombinant African swine fever viruses.

PubMed

Borca, Manuel V; Holinka, Lauren G; Berggren, Keith A; Gladue, Douglas P

2018-02-16

African swine fever virus (ASFV) causes a highly contagious disease called African swine fever. This disease is often lethal for domestic pigs, causing extensive losses for the swine industry. ASFV is a large and complex double stranded DNA virus. Currently there is no commercially available treatment or vaccine to prevent this devastating disease. Development of recombinant ASFV for producing live-attenuated vaccines or studying the involvement of specific genes in virus virulence has relied on the relatively rare event of homologous recombination in primary swine macrophages, causing difficulty to purify the recombinant virus from the wild-type parental ASFV. Here we present the use of the CRISPR-Cas9 gene editing system as a more robust and efficient system to produce recombinant ASFVs. Using CRISPR-Cas9 a recombinant virus was efficiently developed by deleting the non-essential gene 8-DR from the genome of the highly virulent field strain Georgia07 using swine macrophages as cell substrate.

ELiXIR—Solid-State Luminaire With Enhanced Light Extraction by Internal Reflection

NASA Astrophysics Data System (ADS)

Allen, Steven C.; Steckl, Andrew J.

2007-06-01

A phosphor-converted light-emitting diode (pcLED) luminaire featuring enhanced light extraction by internal reflection (ELiXIR) with efficacy of 60 lm/W producing 18 lumens of yellowish green light at 100 mA is presented. The luminaire consists of a commercial blue high power LED, a polymer hemispherical shell lens with interior phosphor coating, and planar aluminized reflector. High extraction efficiency of the phosphor-converted light is achieved by separating the phosphor from the LED and using internal reflection to steer the light away from lossy reflectors and the LED package and out of the device. At 10 and 500 mA, the luminaire produces 2.1 and 66 lumens with efficacies of 80 and 37 lm/W, respectively. Technological improvements over existing commercial LEDs, such as more efficient pcLED packages or, alternatively, higher efficiency green or yellow for color mixing, will be essential to achieving 150 200 lm/W solid-state lighting. Advances in both areas are demonstrated.

Biological construction of single-walled carbon nanotube electron transfer pathways in dye-sensitized solar cells.

PubMed

Inoue, Ippei; Watanabe, Kiyoshi; Yamauchi, Hirofumi; Ishikawa, Yasuaki; Yasueda, Hisashi; Uraoka, Yukiharu; Yamashita, Ichiro

2014-10-01

We designed and mass-produced a versatile protein supramolecule that can be used to manufacture a highly efficient dye-sensitized solar cell (DSSC). Twelve single-walled carbon-nanotube (SWNT)-binding and titanium-mineralizing peptides were genetically integrated on a cage-shaped dodecamer protein (CDT1). A process involving simple mixing of highly conductive SWNTs with CDT1 followed by TiO2 biomineralization produces a high surface-area/weight TiO2 -(anatase)-coated intact SWNT nanocomposite under environmentally friendly conditions. A DSSC with a TiO2 photoelectrode containing 0.2 wt % of the SWNT-TiO2 nanocomposite shows a current density improvement by 80% and a doubling of the photoelectric conversion efficiency. The SWNT-TiO2 nanocomposite transfers photon-generated electrons from dye molecules adsorbed on the TiO2 to the anode electrode swiftly. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

The Draft Genome Sequence of a Novel High-Efficient Butanol-Producing Bacterium Clostridium Diolis Strain WST.

PubMed

Chen, Chaoyang; Sun, Chongran; Wu, Yi-Rui

2018-03-21

A wild-type solventogenic strain Clostridium diolis WST, isolated from mangrove sediments, was characterized to produce high amount of butanol and acetone with negligible level of ethanol and acids from glucose via a unique acetone-butanol (AB) fermentation pathway. Through the genomic sequencing, the assembled draft genome of strain WST is calculated to be 5.85 Mb with a GC content of 29.69% and contains 5263 genes that contribute to the annotation of 5049 protein-coding sequences. Within these annotated genes, the butanol dehydrogenase gene (bdh) was determined to be in a higher amount from strain WST compared to other Clostridial strains, which is positively related to its high-efficient production of butanol. Therefore, we present a draft genome sequence analysis of strain WST in this article that should facilitate to further understand the solventogenic mechanism of this special microorganism.

Process for CO.sub.2 capture using zeolites from high pressure and moderate temperature gas streams

DOEpatents

Siriwardane, Ranjani V [Morgantown, WV; Stevens, Robert W [Morgantown, WV

2012-03-06

A method for separating CO.sub.2 from a gas stream comprised of CO.sub.2 and other gaseous constituents using a zeolite sorbent in a swing-adsorption process, producing a high temperature CO.sub.2 stream at a higher CO.sub.2 pressure than the input gas stream. The method utilizes CO.sub.2 desorption in a CO.sub.2 atmosphere and effectively integrates heat transfers for optimizes overall efficiency. H.sub.2O adsorption does not preclude effective operation of the sorbent. The cycle may be incorporated in an IGCC for efficient pre-combustion CO.sub.2 capture. A particular application operates on shifted syngas at a temperature exceeding 200.degree. C. and produces a dry CO.sub.2 stream at low temperature and high CO.sub.2 pressure, greatly reducing any compression energy requirements which may be subsequently required.

Optimisation of GaN LEDs and the reduction of efficiency droop using active machine learning

DOE PAGES

Rouet-Leduc, Bertrand; Barros, Kipton Marcos; Lookman, Turab; ...

2016-04-26

A fundamental challenge in the design of LEDs is to maximise electro-luminescence efficiency at high current densities. We simulate GaN-based LED structures that delay the onset of efficiency droop by spreading carrier concentrations evenly across the active region. Statistical analysis and machine learning effectively guide the selection of the next LED structure to be examined based upon its expected efficiency as well as model uncertainty. This active learning strategy rapidly constructs a model that predicts Poisson-Schrödinger simulations of devices, and that simultaneously produces structures with higher simulated efficiencies.

High Performance OLED Panel and Luminaire

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

Spindler, Jeffrey

2017-02-20

In this project, OLEDWorks developed and demonstrated the technology required to produce OLED lighting panels with high energy efficiency and excellent light quality. OLED panels developed in this program produce high quality warm white light with CRI greater than 85 and efficacy up to 80 lumens per watt (LPW). An OLED luminaire employing 24 of the high performance panels produces practical levels of illumination for general lighting, with a flux of over 2200 lumens at 60 LPW. This is a significant advance in the state of the art for OLED solid-state lighting (SSL), which is expected to be a complementarymore » light source to the more advanced LED SSL technology that is rapidly replacing all other traditional forms of lighting.« less

Novel dry-desulfurization process using Ca(OH)2/fly ash sorbent in a circulating fluidized bed.

PubMed

Matsushima, Norihiko; Li, Yan; Nishioka, Masateru; Sadakata, Masayoshi; Qi, Haiying; Xu, Xuchang

2004-12-15

A dry-desulfurization process using Ca(OH)2/fly ash sorbent and a circulating fluidized bed (CFB) was developed. Its aim was to achieve high SO2 removal efficiency without humidification and production of CaSO4 as the main byproduct. The CaSO4 produced could be used to treat alkalized soil. An 83% SO2 removal rate was demonstrated, and a byproduct with a high CaSO4 content was produced through baghouse ash. These results indicated that this process could remove SO2 in flue gas with a high efficiency under dry conditions and simultaneously produce soil amendment. It was shown that NO and NO2 enhanced the SO2 removal rate markedly and that NO2 increased the amount of CaSO4 in the final product more than NO. These results confirmed that the significant effects of NO and NO2 on the SO2 removal rate were due to chain reactions that occurred under favorable conditions. The amount of baghouse ash produced increased as the reaction progressed, indicating that discharge of unreacted Ca(OH)2 from the reactor was suppressed. Hence, unreacted Ca(OH)2 had a long residence time in the CFB, resulting in a high SO2 removal rate. It was also found that 350 degrees C is the optimum reaction temperature for dry desulfurization in the range tested (320-380 degrees C).

Why Clone?

MedlinePlus

... have been cloned already, including two relatives of cattle called the guar and the banteng, mouflon sheep, ... are underway to clone agricultural animals, such as cattle and pigs, that are efficient producers of high- ...

Development of advanced inert-gas ion thrusters

NASA Technical Reports Server (NTRS)

Poeschel, R. L.

1983-01-01

Inert gas ion thruster technology offers the greatest potential for providing high specific impulse, low thrust, electric propulsion on large, Earth orbital spacecraft. The development of a thruster module that can be operated on xenon or argon propellant to produce 0.2 N of thrust at a specific impulse of 3000 sec with xenon propellant and at 6000 sec with argon propellant is described. The 30 cm diameter, laboratory model thruster is considered to be scalable to produce 0.5 N thrust. A high efficiency ring cusp discharge chamber was used to achieve an overall thruster efficiency of 77% with xenon propellant and 66% with argon propellant. Measurements were performed to identify ion production and loss processes and to define critical design criteria (at least on a preliminary basis).

Reversal electron attachment ionizer for detection of trace species

NASA Technical Reports Server (NTRS)

Bernius, Mark T. (Inventor); Chutjian, Ara (Inventor)

1990-01-01

An in-line reversal electron, high-current ionizer capable of focusing a beam of electrons to a reversal region and executing a reversal of said electrons, such that the electrons possess zero kinetic energy at the point of reversal, may be used to produce both negative and positive ions. A sample gas is introduced at the point of electron reversal for low energy electron-(sample gas) molecule attachment with high efficiency. The attachment process produces negative ions from the sample gas, which includes species present in trace (minute) amounts. These ions are extracted efficiently and directed to a mass analyzer where they may be detected and identified. The generation and detection of positive ions is accomplished in a similar fashion with minimal adjustment to potentials applied to the apparatus.

Reversal electron attachment ionizer for detection of trace species

NASA Technical Reports Server (NTRS)

Bernius, Mark T. (Inventor); Chutjian, Ara (Inventor)

1989-01-01

An in-line reversal electron, high-current ionizer capable of focusing a beam of electrons to a reversal region and executing a reversal of the electrons, such that the electrons possess zero kinetic energy at the point of reversal, may be used to produce both negative and positive ions. A sample gas is introduced at the point of electron reversal for low energy electron-(sample gas) molecule attachment with high efficiency. The attachment process produces negative ions from the sample gas, which includes species present in trace (minute) amounts. These ions are extracted efficiently and directed to a mass analyzer where they may be detected and identified. The generation and detection of positive ions is accomplished in a similar fashion with minimal adjustment to potentials applied to the apparatus.

Efficient Dual Head Nd:YAG 100mJ Oscillator for Remote Sensing

NASA Technical Reports Server (NTRS)

Coyle, Donald B.; Stysley, Paul R.; Kay, Richard b.; Poulios, Demetrios

2007-01-01

A diode pumped, Nd:YAG laser producing 100 mJ Q-switched pulses and employing a dual-pump head scheme in an unstable resonator configuration is described. Each head contains a side pumped zig-zag slab and four 6-bar QCW 808 nm diodes arrays which are de-rated 23%. Denoting 'z' as the lasing axis, the pump directions were along the x-axis in one head and the y-axis in the other, producing a circularized thermal lens, more typical in laser rod-based cavities. The dual head design's effective thermal lens is now corrected with a proper HR mirror curvature selection. This laser has demonstrated over 100 mJ output with high optical efficiency (24%), good TEM(sub 00) beam quality, and high pointing stability.

Efficiency of a flapping propulsion system based on two side-by-side pitching foils

NASA Astrophysics Data System (ADS)

Huera-Huarte, Francisco

2017-11-01

We explore the propulsive performance of two foils flapping side-by-side in a wide variety of configurations, for different foil separations, pitching amplitudes and frequencies and phase differences. Direct force and torque measurements will be shown in each situation, after a thorough parametric study, that led to the identification of highly efficient modes of propulsion. The especially designed experimental rig allowed the computation of efficiencies globally and at each shaft in the system. Planar and volumetric Particle Image Velocimetry (PIV) allowed a detailed description of the wake generated by the system, for each different kinematics investigated. The investigation is part of an ambitious project with the aim of producing a high efficient and highly manoeuvrable flapping propulsion system for underwater vehicles. Funding from Spanish Ministry MINECO through Grant DPI2015-71645-P is gratefully acknowledged.

Superconducting thermoelectric generator

DOEpatents

Metzger, J.D.; El-Genk, M.S.

1994-01-01

Thermoelectricity is produced by applying a temperature differential to dissimilar electrically conducting or semiconducting materials, thereby producing a voltage that is proportional to the temperature difference. Thermoelectric generators use this effect to directly convert heat into electricity; however, presently-known generators have low efficiencies due to the production of high currents which in turn cause large resistive heating losses. Some thermoelectric generators operate at efficiencies between 4% and 7% in the 800{degrees} to 1200{degrees}C range. According to its major aspects and bradly stated, the present invention is an apparatus and method for producing electricity from heat. In particular, the invention is a thermoelectric generator that juxtaposes a superconducting material and a semiconducting material - so that the superconducting and the semiconducting materials touch - to convert heat energy into electrical energy without resistive losses in the temperature range below the critical temperature of the superconducting material. Preferably, an array of superconducting material is encased in one of several possible configurations within a second material having a high thermal conductivity, preferably a semiconductor, to form a thermoelectric generator.

Investigation of spore coat display of Bacillus subtilis β-galactosidase for developing of whole cell biocatalyst.

PubMed

Tavassoli, Setareh; Hinc, Krzysztof; Iwanicki, Adam; Obuchowski, Michal; Ahmadian, Gholamreza

2013-03-01

The production of highly efficient, recyclable and cost-effective enzymes is one of the most important goals in industrial biotechnology. Bacterial spores are highly resistant to harsh environmental conditions, easy to produce and are suitable for manipulation of genetic materials. These features make them a very efficient tool for biotechnology. Here, we show the use bacterial spores for presentation of functional enzyme. Spore coat display was used to produce a biocatalyst, which expresses β-galactiosidase (LacA). This enzyme is commonly used to produce lactose-free milk for lactose intolerant individuals. The lacA gene from Bacillus subtilis strain 168 was expressed on the surface of B. subtilis RH101(ΔcotC) spores using CotC as protein carrier. Presence of LacA protein is verified by western blotting. Results of β-galactiosidase assay show that the expressed enzyme retained its activity in condition of freezing and drying, as well as after recovery from the reaction's mixture.

Engineering of microorganisms for the production of biofuels and perspectives based on systems metabolic engineering approaches.

PubMed

Jang, Yu-Sin; Park, Jong Myoung; Choi, Sol; Choi, Yong Jun; Seung, Do Young; Cho, Jung Hee; Lee, Sang Yup

2012-01-01

The increasing oil price and environmental concerns caused by the use of fossil fuel have renewed our interest in utilizing biomass as a sustainable resource for the production of biofuel. It is however essential to develop high performance microbes that are capable of producing biofuels with very high efficiency in order to compete with the fossil fuel. Recently, the strategies for developing microbial strains by systems metabolic engineering, which can be considered as metabolic engineering integrated with systems biology and synthetic biology, have been developed. Systems metabolic engineering allows successful development of microbes that are capable of producing several different biofuels including bioethanol, biobutanol, alkane, and biodiesel, and even hydrogen. In this review, the approaches employed to develop efficient biofuel producers by metabolic engineering and systems metabolic engineering approaches are reviewed with relevant example cases. It is expected that systems metabolic engineering will be employed as an essential strategy for the development of microbial strains for industrial applications. Copyright © 2011 Elsevier Inc. All rights reserved.

Diffraction efficiency of radially-profiled off-plane reflection gratings

NASA Astrophysics Data System (ADS)

Miles, Drew M.; Tutt, James H.; DeRoo, Casey T.; Marlowe, Hannah; Peterson, Thomas J.; McEntaffer, Randall L.; Menz, Benedikt; Burwitz, Vadim; Hartner, Gisela; Laubis, Christian; Scholze, Frank

2015-09-01

Future X-ray missions will require gratings with high throughput and high spectral resolution. Blazed off-plane reflection gratings are capable of meeting these demands. A blazed grating profile optimizes grating efficiency, providing higher throughput to one side of zero-order on the arc of diffraction. This paper presents efficiency measurements made in the 0.3 - 1.5 keV energy band at the Physikalisch-Technische Bundesanstalt (PTB) BESSY II facility for three holographically-ruled gratings, two of which are blazed. Each blazed grating was tested in both the Littrow configuration and anti-Littrow configuration in order to test the alignment sensitivity of these gratings with regard to throughput. This paper outlines the procedure of the grating experiment performed at BESSY II and discuss the resulting efficiency measurements across various energies. Experimental results are generally consistent with theory and demonstrate that the blaze does increase throughput to one side of zero-order. However, the total efficiency of the non-blazed, sinusoidal grating is greater than that of the blazed gratings, which suggests that the method of manufacturing these blazed profiles fails to produce facets with the desired level of precision. Finally, evidence of a successful blaze implementation from first diffraction results of prototype blazed gratings produce via a new fabrication technique at the University of Iowa are presented.

Design of Ablation Test Device for Brick Coating of Gun

NASA Astrophysics Data System (ADS)

shirui, YAO; yongcai, CHEN; fei, WANG; jianxin, ZHAO

2018-03-01

As a result of the live ammunition test conditions, the barrel resistance of the barrel coating has high cost, time consuming, low efficiency and high test site requirements. This article designed a simple, convenient and efficient test device. Through the internal trajectory calculation by Matlab, the ablation environment produced by the ablation test device has achieved the expected effect, which is consistent with the working condition of the tube in the launching state, which can better reflect the ablation of the coating.

Promethium-147 capacitor.

PubMed

Kavetskiy, A; Yakubova, G; Lin, Q; Chan, D; Yousaf, S M; Bower, K; Robertson, J D; Garnov, A; Meier, D

2009-06-01

Beta particle surface fluxes for tritium, Ni-63, Pm-147, and Sr-90 sources were calculated in this work. High current density was experimentally achieved from Pm-147 oxide in silica-titana glass. A 96 GBq (2.6 Ci) Pm-147 4pi-source with flux efficiency greater than 50% was used for constructing a direct charge capacitor with a polyimide coated collector and vacuum as electrical insulation. The capacitor connected to high resistance (TOmega) loads produced up to 35 kV. Overall conversion efficiency was over 10% (on optimal load).

High flux, narrow bandwidth compton light sources via extended laser-electron interactions

DOEpatents

Barty, V P

2015-01-13

New configurations of lasers and electron beams efficiently and robustly produce high flux beams of bright, tunable, polarized quasi-monoenergetic x-rays and gamma-rays via laser-Compton scattering. Specifically, the use of long-duration, pulsed lasers and closely-spaced, low-charge and low emittance bunches of electron beams increase the spectral flux of the Compton-scattered x-rays and gamma rays, increase efficiency of the laser-electron interaction and significantly reduce the overall complexity of Compton based light sources.

Efficient enzymatic production of hydroxy fatty acids by linoleic acid Δ9 hydratase from Lactobacillus plantarum AKU 1009a.

PubMed

Takeuchi, M; Kishino, S; Park, S-B; Hirata, A; Kitamura, N; Saika, A; Ogawa, J

2016-05-01

This study aims to produce hydroxy fatty acids efficiently. Escherichia coli overexpressing linoleic acid Δ9 hydratase from Lactobacillus plantarum AKU 1009a was employed to produce hydroxy fatty acids with industrial potential. We found that 280 g l(-1) of linoleic acid (1 mol l(-1)) was converted into (S)-10-hydoxy-cis-12-octadecenoic acid (HYA) with a high conversion rate of 98% (mol/mol) and more than 99·9% enantiomeric excess (e.e.) by recombinant E. coli cells in the presence of FAD and NADH. In the same way, many kinds of C18 unsaturated fatty acids with Δ9 carbon double bond (280 g l(-1)) were converted into corresponding 10-hydroxy fatty acids with the conversion rates over 95% (mol/mol). We also produced HYA at a high rate of accumulation (289 g l(-1) ) with a high yield (97 mol%) in a reaction mixture that contained glucose instead of NADH. We developed a process for producing several types of hydroxy fatty acids with high accumulation rates and high yields. Hydroxy fatty acids are important materials for the chemical, food, cosmetic and pharmaceutical industries, and thus they have recently attracted much interest in a variety of research fields. However, the mass production of hydroxy fatty acids has been limited. This method of hydroxy fatty acids production will facilitate the widespread application of hydroxy fatty acids in various industries. © 2016 The Society for Applied Microbiology.

Microwave Frequency Multiplier

NASA Astrophysics Data System (ADS)

Velazco, J. E.

2017-02-01

High-power microwave radiation is used in the Deep Space Network (DSN) and Goldstone Solar System Radar (GSSR) for uplink communications with spacecraft and for monitoring asteroids and space debris, respectively. Intense X-band (7.1 to 8.6 GHz) microwave signals are produced for these applications via klystron and traveling-wave microwave vacuum tubes. In order to achieve higher data rate communications with spacecraft, the DSN is planning to gradually furnish several of its deep space stations with uplink systems that employ Ka-band (34-GHz) radiation. Also, the next generation of planetary radar, such as Ka-Band Objects Observation and Monitoring (KaBOOM), is considering frequencies in the Ka-band range (34 to 36 GHz) in order to achieve higher target resolution. Current commercial Ka-band sources are limited to power levels that range from hundreds of watts up to a kilowatt and, at the high-power end, tend to suffer from poor reliability. In either case, there is a clear need for stable Ka-band sources that can produce kilowatts of power with high reliability. In this article, we present a new concept for high-power, high-frequency generation (including Ka-band) that we refer to as the microwave frequency multiplier (MFM). The MFM is a two-cavity vacuum tube concept where low-frequency (2 to 8 GHz) power is fed into the input cavity to modulate and accelerate an electron beam. In the second cavity, the modulated electron beam excites and amplifies high-power microwaves at a frequency that is a multiple integer of the input cavity's frequency. Frequency multiplication factors in the 4 to 10 range are being considered for the current application, although higher multiplication factors are feasible. This novel beam-wave interaction allows the MFM to produce high-power, high-frequency radiation with high efficiency. A key feature of the MFM is that it uses significantly larger cavities than its klystron counterparts, thus greatly reducing power density and arcing concerns. We present a theoretical analysis for the beam-wave interactions in the MFM's input and output cavities. We show the conditions required for successful frequency multiplication inside the output cavity. Computer simulations using the plasma physics code MAGIC show that 100 kW of Ka-band (32-GHz) output power can be produced using an 80-kW X-band (8-GHz) signal at the MFM's input. The associated MFM efficiency - from beam power to Ka-band power - is 83 percent. Thus, the overall klystron-MFM efficiency is 42 percent - assuming that a klystron with an efficiency of 50 percent delivers the input signal.

High-efficiency solar-thermophotovoltaic system equipped with a monolithic planar selective absorber/emitter

NASA Astrophysics Data System (ADS)

Shimizu, Makoto; Kohiyama, Asaka; Yugami, Hiroo

2015-01-01

We demonstrate a high-efficiency solar-thermophotovoltaic system (STPV) using a monolithic, planar, and spectrally selective absorber/emitter. A complete STPV system using gallium antimonide (GaSb) cells was designed and fabricated to conduct power generation tests. To produce a high-efficiency STPV, it is important to match the thermal radiation spectrum with the sensitive region of the GaSb cells. Therefore, to reach high temperatures with low incident power, a planar absorber/emitter is incorporated for controlling the thermal radiation spectrum. This multilayer coating consists of thin-film tungsten sandwiched by yttria-stabilized zirconia. The system efficiency is estimated to be 16% when accounting for the optical properties of the fabricated absorber/emitter. Power generation tests using a high-concentration solar simulator show that the absorber/emitter temperature peaks at 1640 K with an incident power density of 45 W/cm2, which can be easily obtained by low-cost optics such as Fresnel lenses. The conversion efficiency became 23%, exceeding the Shockley-Queisser limit for GaSb, with a bandgap of 0.67 eV. Furthermore, a total system efficiency of 8% was obtained with the view factor between the emitter and the cell assumed to be 1.

Highly efficient water-mediated approach to access benzazoles: metal catalyst and base-free synthesis of 2-substituted benzimidazoles, benzoxazoles, and benzothiazoles.

PubMed

Bala, Manju; Verma, Praveen Kumar; Sharma, Deepika; Kumar, Neeraj; Singh, Bikram

2015-05-01

An efficient water-catalyzed method has been developed for the synthesis of 2-substituted benzimidazoles, benzoxazoles, and benzothiazoles in one step. The present method excludes the usage of toxic metal catalysts and bases to produce benzazoles in good to excellent yields. An efficient and versatile water-mediated method has been established for the synthesis of various 2-arylbenzazoles. The present protocol excludes the usage of any catalyst and additive provided excellent selectivities and yields with high functional group tolerance for the synthesis of 2-arylated benzimidazoles, benzoxazoles, and benzothiazoles. Benzazolones were also synthesized using similar reaction protocol.

High-power waveguide resonator second harmonic device with external conversion efficiency up to 75%

NASA Astrophysics Data System (ADS)

Stefszky, M.; Ricken, R.; Eigner, C.; Quiring, V.; Herrmann, H.; Silberhorn, C.

2018-06-01

We report on a highly efficient waveguide resonator device for the production of 775 nm light using a titanium indiffused LiNbO3 waveguide resonator. When scanning the resonance, the device produces up to 110 mW of second harmonic power with 140 mW incident on the device—an external conversion efficiency of 75%. The cavity length is also locked, using a Pound–Drever–Hall type locking scheme, involving feedback to either the cavity temperature or the laser frequency. With laser frequency feedback, a stable output power of approximately 28 mW from a 52 mW pump is seen over one hour.

Quantitative Modeling of Cerenkov Light Production Efficiency from Medical Radionuclides

PubMed Central

Beattie, Bradley J.; Thorek, Daniel L. J.; Schmidtlein, Charles R.; Pentlow, Keith S.; Humm, John L.; Hielscher, Andreas H.

2012-01-01

There has been recent and growing interest in applying Cerenkov radiation (CR) for biological applications. Knowledge of the production efficiency and other characteristics of the CR produced by various radionuclides would help in accessing the feasibility of proposed applications and guide the choice of radionuclides. To generate this information we developed models of CR production efficiency based on the Frank-Tamm equation and models of CR distribution based on Monte-Carlo simulations of photon and β particle transport. All models were validated against direct measurements using multiple radionuclides and then applied to a number of radionuclides commonly used in biomedical applications. We show that two radionuclides, Ac-225 and In-111, which have been reported to produce CR in water, do not in fact produce CR directly. We also propose a simple means of using this information to calibrate high sensitivity luminescence imaging systems and show evidence suggesting that this calibration may be more accurate than methods in routine current use. PMID:22363636

Transparent Ti-In-Sn-O multicomponent anodes for highly efficient phosphorescent organic light emitting diodes

NASA Astrophysics Data System (ADS)

Lim, Jong-Wook; Jun Kang, Seong; Lee, Sunghun; Kim, Jang-Joo; Kim, Han-Ki

2012-07-01

We report on transparent Ti-In-Sn-O (TITO) multicomponent anodes prepared by co-sputtering anatase TiO2-x and ITO targets to produce highly efficient phosphorescent organic light emitting diodes (OLEDs). In spite of the incorporation of low cost TiO2, the crystalline TITO electrode annealed at temperature of 600 °C showed a sheet resistance of 18.06 Ω/sq, an optical transmittance of 87.96% at a wavelength of 550 nm, and a work function of 4.71 eV comparable to conventional ITO electrode. Both the quantum (21.69%) and power efficiencies (90.92 lm/W) of the phosphorescent OLED fabricated on the TITO anode were higher than those of the OLED with the reference ITO anode due to the high transparency of the TITO electrodes. This indicates that the TITO electrode is a promising indium-saving electrode that can replace high-cost ITO electrodes in the manufacture of low-cost, highly efficient phosphorescent OLEDs.

Breed of cow and herd productivity affect milk nutrient recovery in curd, and cheese yield, efficiency and daily production.

PubMed

Stocco, G; Cipolat-Gotet, C; Gasparotto, V; Cecchinato, A; Bittante, G

2018-02-01

Little is known about cheese-making efficiency at the individual cow level, so our objective was to study the effects of herd productivity, individual herd within productivity class and breed of cow within herd by producing, then analyzing, 508 model cheeses from the milk of 508 cows of six different breeds reared in 41 multi-breed herds classified into two productivity classes (high v. low). For each cow we obtained six milk composition traits; four milk nutrient (fat, protein, solids and energy) recovery traits (REC) in curd; three actual % cheese yield traits (%CY); two theoretical %CYs (fresh cheese and cheese solids) calculated from milk composition; two overall cheese-making efficiencies (% ratio of actual to theoretical %CYs); daily milk yield (dMY); and three actual daily cheese yield traits (dCY). The aforementioned phenotypes were analyzed using a mixed model which included the fixed effects of herd productivity, parity, days in milk (DIM) and breed; the random effects were the water bath, vat, herd and residual. Cows reared in high-productivity herds yielded more milk with higher nutrient contents and more cheese per day, had greater theoretical %CY, and lower cheese-making efficiency than low-productivity herds, but there were no differences between them in terms of REC traits. Individual herd within productivity class was an intermediate source of total variation in REC, %CY and efficiency traits (10.0% to 17.2%), and a major source of variation in milk yield and dCY traits (43.1% to 46.3%). Parity of cows was an important source of variation for productivity traits, whereas DIM affected almost all traits. Breed within herd greatly affected all traits. Holsteins produced more milk, but Brown Swiss cows produced milk with higher actual and theoretical %CYs and cheese-making efficiency, so that the two large-framed breeds had the same dCY. Compared with the two large-framed breeds, the small Jersey cows produced much less milk, but with greater actual and theoretical %CYs, similar efficiencies and a slightly lower dCY. Compared with the average of the specialized dairy breeds, the three dual-purpose breeds (Simmental and the local Rendena and Alpine Grey) had, on average, similar dMY, lower actual and theoretical %CY, similar fat and protein REC, and slightly greater cheese-making efficiency.

Three-stage linear, split-Stirling cryocooler for 1 to 2K magnetic cold stage

NASA Technical Reports Server (NTRS)

Longsworth, R. C.

1993-01-01

A long-life, linear, high efficiency 8K split Stirling cycle cryocooler was designed, built, and tested. The refrigerator is designed for cooling a 50 mW, 1.5K magnetic cold stage. Dual opposed piston compressors are driven by moving-coil linear motors. The three stage expander, although not completed, is also driven by a linear motor and is designed to produce 1 SW at 60K, 4W at 16K, and 1.2W at 8K. The cold regenerator employs a parallel gap construction for high efficiency. The key technology areas addressed include warm and cold flexible suspension bearings and a new cold regenerator geometry for high efficiency at 8K.

Nanostructured Materials for Solar Cells

NASA Technical Reports Server (NTRS)

Bailey, Sheila; Raffaelle, Ryne; Castro, Stephanie; Fahey, S.; Gennett, T.; Tin, P.

2003-01-01

The use of both inorganic and organic nanostructured materials in producing high efficiency photovoltaics is discussed in this paper. Recent theoretical results indicate that dramatic improvements in device efficiency may be attainable through the use of semiconductor quantum dots in an ordinary p-i-n solar cell. In addition, it has also recently been demonstrated that quantum dots can also be used to improve conversion efficiencies in polymeric thin film solar cells. A similar improvement in these types of cells has also been observed by employing single wall carbon nanotubes. This relatively new carbon allotrope may assist both in the disassociation of excitons as well as carrier transport through the composite material. This paper reviews the efforts that are currently underway to produce and characterize these nanoscale materials and to exploit their unique properties.

Tuneable light-emitting carbon-dot/polymer flexible films prepared through one-pot synthesis

NASA Astrophysics Data System (ADS)

Bhunia, Susanta Kumar; Nandi, Sukhendu; Shikler, Rafi; Jelinek, Raz

2016-02-01

Development of efficient, inexpensive, and environmentally-friendly light emitters, particularly devices that produce white light, have drawn intense interest due to diverse applications in the lighting industry, photonics, solar energy, and others. We present a simple strategy for the fabrication of flexible transparent films exhibiting tuneable light emission through one-pot synthesis of polymer matrixes with embedded carbon dots assembled in situ. Importantly, different luminescence colours were produced simply by preparing C-dot/polymer films using carbon precursors that yielded C-dots exhibiting distinct fluorescence emission profiles. Furthermore, mixtures of C-dot precursors could be also employed for fabricating films exhibiting different colours. In particular, we successfully produced films emitting white light with attractive properties (i.e. ``warm'' white light with a high colour rendering index) - a highly sought after goal in optical technologies.Development of efficient, inexpensive, and environmentally-friendly light emitters, particularly devices that produce white light, have drawn intense interest due to diverse applications in the lighting industry, photonics, solar energy, and others. We present a simple strategy for the fabrication of flexible transparent films exhibiting tuneable light emission through one-pot synthesis of polymer matrixes with embedded carbon dots assembled in situ. Importantly, different luminescence colours were produced simply by preparing C-dot/polymer films using carbon precursors that yielded C-dots exhibiting distinct fluorescence emission profiles. Furthermore, mixtures of C-dot precursors could be also employed for fabricating films exhibiting different colours. In particular, we successfully produced films emitting white light with attractive properties (i.e. ``warm'' white light with a high colour rendering index) - a highly sought after goal in optical technologies. Electronic supplementary information (ESI) available. See DOI: 10.1039/c5nr08400h

Producing Hydrogen by Plasma Pyrolysis of Methane

NASA Technical Reports Server (NTRS)

Atwater, James; Akse, James; Wheeler, Richard

2010-01-01

Plasma pyrolysis of methane has been investigated for utility as a process for producing hydrogen. This process was conceived as a means of recovering hydrogen from methane produced as a byproduct of operation of a life-support system aboard a spacecraft. On Earth, this process, when fully developed, could be a means of producing hydrogen (for use as a fuel) from methane in natural gas. The most closely related prior competing process - catalytic pyrolysis of methane - has several disadvantages: a) The reactor used in the process is highly susceptible to fouling and deactivation of the catalyst by carbon deposits, necessitating frequent regeneration or replacement of the catalyst. b) The reactor is highly susceptible to plugging by deposition of carbon within fixed beds, with consequent channeling of flow, high pressure drops, and severe limitations on mass transfer, all contributing to reductions in reactor efficiency. c) Reaction rates are intrinsically low. d) The energy demand of the process is high.

Anaerobic digestion of post-hydrothermal liquefaction wastewater for improved energy efficiency of hydrothermal bioenergy processes.

PubMed

Zhou, Yan; Schideman, Lance; Zheng, Mingxia; Martin-Ryals, Ana; Li, Peng; Tommaso, Giovana; Zhang, Yuanhui

2015-01-01

Hydrothermal liquefaction (HTL) is a promising process for converting wet biomass and organic wastes into bio-crude oil. It also produces an aqueous product referred to as post-hydrothermal liquefaction wastewater (PHWW) containing up to 40% of the original feedstock carbon, which reduces the overall energy efficiency of the HTL process. This study investigated the feasibility of using anaerobic digestion (AD) to treat PHWW, with the aid of activated carbon. Results showed that successful AD occurred at relatively low concentrations of PHWW (≤ 6.7%), producing a biogas yield of 0.5 ml/mg CODremoved, and ∼53% energy recovery efficiency. Higher concentrations of PHWW (≥13.3%) had an inhibitory effect on the AD process, as indicated by delayed, slower, or no biogas production. Activated carbon was shown to effectively mitigate this inhibitory effect by enhancing biogas production and allowing digestion to proceed at higher PHWW concentrations (up to 33.3%), likely due to sequestering toxic organic compounds. The addition of activated carbon also increased the net energy recovery efficiency of AD with a relatively high concentration of PHWW (33.3%), taking into account the energy for producing activated carbon. These results suggest that AD is a feasible approach to treat PHWW, and to improve the energy efficiency of the HTL processes.

Efficiency Enhancement in DC Pulsed Gas Discharge Memory Panel

NASA Astrophysics Data System (ADS)

Okamoto, Yukio

1983-01-01

Much improvement in the luminous efficiency of a dc pulsed gas discharge memory panel for color TV display was achieved by shortening the sustaining pulse duration. High energy electrons can thus be produced in the pulsed discharge with fast rise times. Calculated optimum value of E/P in a Xe gas discharge is 7-8 V/cm\\cdotTorr.

Assessing genetic variation in lettuce for traits related to nitrogen use efficiency using susceptibility and relative efficiency indices

USDA-ARS?s Scientific Manuscript database

Lettuce is a high value commodity in the USA with annual value of ~$2.5 billion. California produces ~75 percent of all lettuce in the country. Overuse of agricultural inputs for crop production can cause detrimental effects to the health of Californians as well as on agricultural and natural resour...

Scalable Production Method for Graphene Oxide Water Vapor Separation Membranes

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

Fifield, Leonard S.; Shin, Yongsoon; Liu, Wei

ABSTRACT Membranes for selective water vapor separation were assembled from graphene oxide suspension using techniques compatible with high volume industrial production. The large-diameter graphene oxide flake suspensions were synthesized from graphite materials via relatively efficient chemical oxidation steps with attention paid to maintaining flake size and achieving high graphene oxide concentrations. Graphene oxide membranes produced using scalable casting methods exhibited water vapor flux and water/nitrogen selectivity performance meeting or exceeding that of membranes produced using vacuum-assisted laboratory techniques. (PNNL-SA-117497)

A synthetic microbial consortium of Shewanella and Bacillus for enhanced generation of bioelectricity.

PubMed

Liu, Ting; Yu, Yang-Yang; Chen, Tao; Chen, Wei Ning

2017-03-01

In this study, a synthetic microbial consortium containing exoelectrogen Shewanella oneidensis MR-1 and riboflavin-producing strain, Bacillus subtilis RH33, was rationally designed and successfully constructed, enabling a stable, multiple cycles of microbial fuel cells (MFCs) operation for more than 500 h. The maximum power density of MFCs with this synthetic microbial consortium was 277.4 mW/m 2 , which was 4.9 times of that with MR-1 (56.9 mW/m 2 ) and 40.2 times of RH33 (6.9 mW/m 2 ), separately. At the same time, the Coulombic efficiency of the synthetic microbial consortium (5.6%) was higher than MR-1 (4.1%) and RH33 (2.3%). Regardless the high concentration of riboflavin produced by RH33, the power density of RH33 was rather low. The low bioelectricity generation can be ascribed to the low efficiency of RH33 in utilizing riboflavin for extracellular electron transfer (EET). In the synthetic microbial consortium of MR-1 and RH33, it was found that both mediated and direct electron transfer efficiencies were enhanced. By exchanging the anolyte of MR-1 and RH33, it was confirmed that the improved MFC performance with the synthetic microbial consortium was because MR-1 could efficiently utilize the high concentration of riboflavin produced by RH33. Biotechnol. Bioeng. 2017;114: 526-532. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

Modelling bio-electrosynthesis in a reverse microbial fuel cell to produce acetate from CO2 and H2O.

PubMed

Kazemi, M; Biria, D; Rismani-Yazdi, H

2015-05-21

Bio-electrosynthesis is one of the significant developments in reverse microbial fuel cell technology which is potentially capable of creating organic compounds by combining CO2 with H2O. Accordingly, the main objective in the current study was to present a model of microbial electrosynthesis for producing organic compounds (acetate) based on direct conduction of electrons in biofilms. The proposed model enjoys a high degree of rigor because it can predict variations in the substrate concentration, electrical potential, current density and the thickness of the biofilm. Additionally, coulombic efficiency was investigated as a function of substrate concentration and cathode potential. For a system containing CO2 as the substrate and Sporomusa ovata as the biofilm forming microorganism, an increase in the substrate concentration at a constant potential can lead to a decrease in coulombic efficiency as well as an increase in current density and biofilm thickness. On the other hand, an increase in the surface cathodic voltage at a constant substrate concentration may result in an increase in the coulombic efficiency and a decrease in the current density. The maximum coulombic efficiency was revealed to be 75% at a substrate concentration of 0.025 mmol cm(-3) and 55% at a surface cathodic voltage of -0.3 V producing a high range of acetate production by creating an optimal state in the concentration and potential intervals. Finally, the validity of the model was verified by comparing the obtained results with related experimental findings.

Photoproduction of I2, Br2, and Cl2 on n-semiconducting powder

NASA Technical Reports Server (NTRS)

Reichman, B.; Byvik, C. E.

1981-01-01

The photosynthetic production of Br2 and Cl2 and the photocatalytic production of I2 from aqueous solutions of the respective halide ions in the presence of platinized semiconducting n-TiO2 powder are reported. Reactions were produced in 2-3 M oxygen-saturated aqueous solutions of KI, KBr or NaCl containing Pt-TiO2 powder which were irradiated by a high-pressure mercury lamp at a power of 400 mW/sq cm. Halogens are found to be produced in greater quantities when platinized TiO2 powders are used rather than pure TiO2, and rates of halogen production are observed to increase from Cl2 to Br2 to I2. The presence of the synthetic reactions producing Br2 and Cl2 with a net influx of energy indicates that an effective separation of the photoproduced electron-hole pair occurs in the semiconductor. Quantum efficiencies of the reaction, which increase with decreasing solution pH, are found to be as high as 30%, implying a solar-to-chemical energy conversion efficiency between 0.03% and 3% for the case of chlorine production. It is concluded that the photoproduction of halogens may be of practical value if product halogens are efficiently removed from the reaction cell.

Energy comparison between solar thermal power plant and photovoltaic power plant

NASA Astrophysics Data System (ADS)

Novosel, Urška; Avsec, Jurij

2017-07-01

The combined use of renewable energy and alternative energy systems and better efficiency of energy devices is a promising approach to reduce effects due to global warming in the world. On the basis of first and second law of thermodynamics we could optimize the processes in the energy sector. The presented paper shows the comparison between solar thermal power plant and photovoltaic power plant in terms of energy, exergy and life cycle analysis. Solar thermal power plant produces electricity with basic Rankine cycle, using solar tower and solar mirrors to produce high fluid temperature. Heat from the solar system is transferred by using a heat exchanger to Rankine cycle. Both power plants produce hydrogen via electrolysis. The paper shows the global efficiency of the system, regarding production of the energy system.

Enzymatic hydrolysis of steam-pretreated lignocellulosic materials with Trichoderma atroviride enzymes produced in-house

PubMed Central

Kovacs, Krisztina; Macrelli, Stefano; Szakacs, George; Zacchi, Guido

2009-01-01

Background Improvement of the process of cellulase production and development of more efficient lignocellulose-degrading enzymes are necessary in order to reduce the cost of enzymes required in the biomass-to-bioethanol process. Results Lignocellulolytic enzyme complexes were produced by the mutant Trichoderma atroviride TUB F-1663 on three different steam-pretreated lignocellulosic substrates, namely spruce, wheat straw and sugarcane bagasse. Filter paper activities of the enzymes produced on the three materials were very similar, while β-glucosidase and hemicellulase activities were more dependent on the nature of the substrate. Hydrolysis of the enzyme preparations investigated produced similar glucose yields. However, the enzymes produced in-house proved to degrade the xylan and the xylose oligomers less efficiently than a commercial mixture of cellulase and β-glucosidase. Furthermore, accumulation of xylose oligomers was observed when the TUB F-1663 supernatants were applied to xylan-containing substrates, probably due to the low β-xylosidase activity of the enzymes. The efficiency of the enzymes produced in-house was enhanced by supplementation with extra commercial β-glucosidase and β-xylosidase. When the hydrolytic capacities of various mixtures of a commercial cellulase and a T. atroviride supernatant produced in the lab were investigated at the same enzyme loading, the glucose yield appeared to be correlated with the β-glucosidase activity, while the xylose yield seemed to be correlated with the β-xylosidase level in the mixtures. Conclusion Enzyme supernatants produced by the mutant T. atroviride TUB F-1663 on various pretreated lignocellulosic substrates have good filter paper activity values combined with high levels of β-glucosidase activities, leading to cellulose conversion in the enzymatic hydrolysis that is as efficient as with a commercial cellulase mixture. On the other hand, in order to achieve good xylan conversion, the supernatants produced by the mutant have to be supplemented with additional β-xylosidase activity. PMID:19580644

Neutron/gamma pulse shape discrimination (PSD) in plastic scintillators with digital PSD electronics

NASA Astrophysics Data System (ADS)

Hutcheson, Anthony L.; Simonson, Duane L.; Christophersen, Marc; Phlips, Bernard F.; Charipar, Nicholas A.; Piqué, Alberto

2013-05-01

Pulse shape discrimination (PSD) is a common method to distinguish between pulses produced by gamma rays and neutrons in scintillator detectors. This technique takes advantage of the property of many scintillators that excitations by recoil protons and electrons produce pulses with different characteristic shapes. Unfortunately, many scintillating materials with good PSD properties have other, undesirable properties such as flammability, toxicity, low availability, high cost, and/or limited size. In contrast, plastic scintillator detectors are relatively low-cost, and easily handled and mass-produced. Recent studies have demonstrated efficient PSD in plastic scintillators using a high concentration of fluorescent dyes. To further investigate the PSD properties of such systems, mixed plastic scintillator samples were produced and tested. The addition of up to 30 wt. % diphenyloxazole (DPO) and other chromophores in polyvinyltoluene (PVT) results in efficient detection with commercial detectors. These plastic scintillators are produced in large diameters up to 4 inches by melt blending directly in a container suitable for in-line detector use. This allows recycling and reuse of materials while varying the compositions. This strategy also avoids additional sample handling and polishing steps required when using removable molds. In this presentation, results will be presented for different mixed-plastic compositions and compared with known scintillating materials

Tree resistance to Lymantria dispar caterpillars: importance and limitations of foliar tannin composition.

PubMed

Barbehenn, Raymond V; Jaros, Adam; Lee, Grace; Mozola, Cara; Weir, Quentin; Salminen, Juha-Pekka

2009-04-01

The ability of foliar tannins to increase plant resistance to herbivores is potentially determined by the composition of the tannins; hydrolyzable tannins are much more active as prooxidants in the guts of caterpillars than are condensed tannins. By manipulating the tannin compositions of two contrasting tree species, this work examined: (1) whether increased levels of hydrolyzable tannins increase the resistance of red oak (Quercus rubra L.), a tree with low resistance that produces mainly condensed tannins, and (2) whether increased levels of condensed tannins decrease the resistance of sugar maple (Acer saccharum Marsh.), a tree with relatively high resistance that produces high levels of hydrolyzable tannins. As expected, when Lymantria dispar L. caterpillars ingested oak leaves coated with hydrolyzable tannins, levels of hydrolyzable tannin oxidation increased in their midgut contents. However, increased tannin oxidation had no significant impact on oxidative stress in the surrounding midgut tissues. Although growth efficiencies were decreased by hydrolyzable tannins, growth rates remained unchanged, suggesting that additional hydrolyzable tannins are not sufficient to increase the resistance of oak. In larvae on condensed tannin-coated maple, no antioxidant effects were observed in the midgut, and levels of tannin oxidation remained high. Consequently, neither oxidative stress in midgut tissues nor larval performance were significantly affected by high levels of condensed tannins. Post hoc comparisons of physiological mechanisms related to tree resistance revealed that maple produced not only higher levels of oxidative stress in the midgut lumen and midgut tissues of L. dispar, but also decreased protein utilization efficiency compared with oak. Our results suggest that high levels of hydrolyzable tannins are important for producing oxidative stress, but increased tree resistance to caterpillars may require additional factors, such as those that produce nutritional stress.

Comparison of electro-fusion and intracytoplasmic nuclear injection methods in pig cloning.

PubMed

Kurome, Mayuko; Fujimura, Tatsuya; Murakami, Hiroshi; Takahagi, Yoichi; Wako, Naohiro; Ochiai, Takashi; Miyazaki, Koji; Nagashima, Hiroshi

2003-01-01

This paper methodologically compares the electro-fusion (EF) and intracytoplasmic injection (ICI) methods, as well as simultaneous fusion/activation (SA) and delayed activation (DA), in somatic nuclear transfer in pigs using fetal fibroblast cells. Comparison of the remodeling pattern of donor nuclei after nuclear transfer by ICI or EF showed that a high rate (80-100%) of premature chromosome condensation occurred in both cases whether or not Ca2+ was present in the fusion medium. Formation of pseudo-pronuclei tended to be lower for nuclear transfer performed by the ICI method (65% vs. 85-97%, p < 0.05). In vitro developmental potential of nuclear transfer embryos reconstructed with IVM oocytes using the EF method was higher than that of those produced by the ICI method (blastocyst formation: 19 vs. 5%, p < 0.05), and it was not improved using in vivo-matured oocytes as recipient cytoplasts. Embryos produced using SA protocol developed to blastocysts with the same degree of efficiency as those produced under the DA protocol (11 vs. 12%). Use of the EF method in conjunction with SA was shown to be an efficient method for producing cloned pigs based on producing a cloned normal pig fetus. However, subtle differences in nuclear remodeling patterns between the SA and DA protocols may imply variations in their nuclear reprogramming efficiency.

Electrical Activation Studies of Silicon Implanted Aluminum Gallium Nitride with High Aluminum Mole Fraction

DTIC Science & Technology

2007-12-01

realized with silicon due to its indirect band gap that results in poor quantum efficiency . The first LEDs and laser diodes were developed with...deep UV (λ < 340 nm) still face many challenges and have low internal quantum efficiency . Jong Kyu Kim et al. have developed a light emitting triode...LET) to try to overcome some of the challenges and 16 have produced a lighting device with increased quantum efficiency (16). AlxGa1-xN has been

Process and apparatus for separating fine particles by microbubble flotation together with a process and apparatus for generation of microbubbles

DOEpatents

Yoon, R.H.; Adel, G.T.; Luttrell, G.H.

1991-01-01

A method and apparatus are disclosed for the microbubble flotation separation of very fine particles, especially coal, so as to produce a high purity and large recovery efficiently. This is accomplished through the use of a high aspect ratio flotation column, microbubbles, and a countercurrent use of wash water to gently wash the froth. Also, disclosed are unique processes and apparatus for generating microbubbles for flotation in a high efficient and inexpensive manner using either a porous tube or an in-line static generator. 23 figures.

Apparatus and process for the separation of hydrophobic and hydrophilic particles using microbubble column flotation together with a process and apparatus for generation of microbubbles

DOEpatents

Yoon, Roe-Hoan; Adel, Gregory T.; Luttrell, Gerald H.

1992-01-01

A method and apparatus are disclosed for the microbubble flotation separation of very fine and coarse particles, especially coal and minerals, so as to produce high purity and high recovery efficiency. This is accomplished through the use of a flotation column, microbubbles, recycling of the flotation pulp, and countercurrent wash water to gently wash the froth. Also disclosed are unique processes and apparatus for generating microbubbles for flotation in a highly efficient and inexpensive manner using either a porous tube or in-line static generators.

Apparatus for the separation of hydrophobic and hydrophilic particles using microbubble column flotation together with a process and apparatus for generation of microbubbles

DOEpatents

Yoon, Roe-Hoan; Adel, Gregory T.; Luttrell, Gerald H.

1995-01-01

An apparatus is disclosed for the microbubble flotation separation of very fine and coarse particles, especially coal, and minerals so as to produce high purity and high recovery efficiency. This is accomplished through the use of a flotation column, microbubbles, recycling of the flotation pulp, and countercurrent wash water to gently wash the froth. Also disclosed are unique processes and apparatus for generating microbubbles for flotation in a highly efficient and inexpensive manner using either a porous tube or in-line static generators.

Apparatus for the separation of hydrophobic and hydrophilic particles using microbubble column flotation together with a process and apparatus for generation of microbubbles

DOEpatents

Yoon, R.H.; Adel, G.T.; Luttrell, G.H.

1995-03-14

An apparatus is disclosed for the microbubble flotation separation of very fine and coarse particles, especially coal, and minerals so as to produce high purity and high recovery efficiency. This is accomplished through the use of a flotation column, microbubbles, recycling of the flotation pulp, and countercurrent wash water to gently wash the froth. Also disclosed are unique processes and apparatus for generating microbubbles for flotation in a highly efficient and inexpensive manner using either a porous tube or in-line static generators. 14 figs.

Apparatus and process for the separation of hydrophobic and hydrophilic particles using microbubble column flotation together with a process and apparatus for generation of microbubbles

DOEpatents

Yoon, Roe-Hoan; Adel, Gregory T.; Luttrell, Gerald H.

1998-01-01

A method and apparatus are disclosed for the microbubble flotation separation of very fine and coarse particles, especially coal and minerals, so as to produce high purity and high recovery efficiency. This is accomplished through the use of a flotation column, microbubbles, recycling of the flotation pulp, and countercurrent wash water to gently wash the froth. Also disclosed are unique processes and apparatus for generating microbubbles for flotation in a highly efficient and inexpensive manner using either a porous tube or in-line static generators.

High-power and highly efficient diode-cladding-pumped holmium-doped fluoride fiber laser operating at 2.94 microm.

PubMed

Jackson, Stuart D

2009-08-01

A high-power diode-cladding-pumped Ho(3+), Pr(3+)-doped fluoride glass fiber laser is demonstrated. The laser produced a maximum output power of 2.5 W at a slope efficiency of 32% using diode lasers emitting at 1,150 nm. The long-emission wavelength of 2.94 microm measured at maximum pump power, which is particularly suited to medical applications, indicates that tailoring of the proportion of Pr(3+) ions can provide specific emission wavelengths while providing sufficient de-excitation of the lower laser level.

Lysosome-controlled efficient ROS overproduction against cancer cells with a high pH-responsive catalytic nanosystem

NASA Astrophysics Data System (ADS)

Fu, Jingke; Shao, Yiran; Wang, Liyao; Zhu, Yingchun

2015-04-01

Excess reactive oxygen species (ROS) have been proved to damage cancer cells efficiently. ROS overproduction is thus greatly desirable for cancer therapy. To date, ROS production is generally uncontrollable and outside cells, which always bring severe side-effects in the vasculature. Since most ROS share a very short half-life and primarily react close to their site of formation, it would be more efficient if excess ROS are controllably produced inside cancer cells. Herein, we report an efficient lysosome-controlled ROS overproduction via a pH-responsive catalytic nanosystem (FeOx-MSNs), which catalyze the decomposition of H2O2 to produce considerable ROS selectively inside the acidic lysosomes (pH 5.0) of cancer cells. After a further incorporation of ROS-sensitive TMB into the nanosystem (FeOx-MSNs-TMB), both a distinct cell labeling and an efficient death of breast carcinoma cells are obtained. This lysosome-controlled efficient ROS overproduction suggests promising applications in cancer treatments.Excess reactive oxygen species (ROS) have been proved to damage cancer cells efficiently. ROS overproduction is thus greatly desirable for cancer therapy. To date, ROS production is generally uncontrollable and outside cells, which always bring severe side-effects in the vasculature. Since most ROS share a very short half-life and primarily react close to their site of formation, it would be more efficient if excess ROS are controllably produced inside cancer cells. Herein, we report an efficient lysosome-controlled ROS overproduction via a pH-responsive catalytic nanosystem (FeOx-MSNs), which catalyze the decomposition of H2O2 to produce considerable ROS selectively inside the acidic lysosomes (pH 5.0) of cancer cells. After a further incorporation of ROS-sensitive TMB into the nanosystem (FeOx-MSNs-TMB), both a distinct cell labeling and an efficient death of breast carcinoma cells are obtained. This lysosome-controlled efficient ROS overproduction suggests promising applications in cancer treatments. Electronic supplementary information (ESI) available: Experimental section, supplementary figures and characterization of as-prepared compounds. See DOI: 10.1039/c5nr00706b

The mineralogy of bauxite for producing smelter-grade alumina

NASA Astrophysics Data System (ADS)

Authier-Martin, M.; Forte, G.; Ostap, S.; See, J.

2001-12-01

Aluminum-producing companies rely on low-cost, high-purity, smelter-grade alumina (aluminum oxide), and alumina production utilizes the bulk of bauxites mined world-wide. The mineralogy of the bauxites has a significant impact on the operation of the Bayer process for alumina production. Typically, the Bayer process produces smelter-grade alumina of 99.5% Al2O3, starting from bauxite containing 30% to 60% Al2O3. The main objective of the Bayer process is to extract the maximum amount of aluminum from the bauxite at as high an aluminate concentration in solution as possible, while limiting any troublesome side reactions. Only with a better understanding of the chemistry of the mineral species and a strict control of the operating/processing conditions can the Bayer process produce efficiently, a low cost, high-quality alumina with minimum detrimental environmental impact.

Wetlands can produce excellent hardwoods and shelter for game

Treesearch

Robert L. Johnson

1985-01-01

From Virginia to Texas, there are about 30 million acres of forests in swamps, creek margins, and river bottoms. These bottomland areas can be efficient producers of high-quality hardwoods, and they are unexcelled as habitat for many species of game and nongame birds and animals. In fact, the southern bottomlands are extremely diverse in species, sites, wood qualities...

Reactivation of Breast Cancer Micrometastases by Senescent Bone Marrow Stroma

DTIC Science & Technology

2011-07-01

Strep, 0.28 mM L-Ascorbic Acid 2-Phosphate and 10 mM β- Glycerophosphate and 1 ml was added on to each Disc placed in a 24 well dish and incubated at... Glycerophosphate . Mouse osteoclasts produced numerous, measurable lacunae at a high efficiency while MC3T3 E1 (Preosteoblasts) and MCF-7 did not produce

Fully Controllable Pancharatnam-Berry Metasurface Array with High Conversion Efficiency and Broad Bandwidth

PubMed Central

Liu, Chuanbao; Bai, Yang; Zhao, Qian; Yang, Yihao; Chen, Hongsheng; Zhou, Ji; Qiao, Lijie

2016-01-01

Metasurfaces have powerful abilities to manipulate the properties of electromagnetic waves flexibly, especially the modulation of polarization state for both linearly polarized (LP) and circularly polarized (CP) waves. However, the transmission efficiency of cross-polarization conversion by a single-layer metasurface has a low theoretical upper limit of 25% and the bandwidth is usually narrow, which cannot be resolved by their simple additions. Here, we efficiently manipulate polarization coupling in multilayer metasurface to promote the transmission of cross-polarization by Fabry-Perot resonance, so that a high conversion coefficient of 80–90% of CP wave is achieved within a broad bandwidth in the metasurface with C-shaped scatters by theoretical calculation, numerical simulation and experiments. Further, fully controlling Pancharatnam-Berry phase enables to realize polarized beam splitter, which is demonstrated to produce abnormal transmission with high conversion efficiency and broad bandwidth. PMID:27703254

Efficient electrochemical remediation of microcystin-LR in tap water using designer TiO2@carbon electrodes

NASA Astrophysics Data System (ADS)

Sanz Lobón, Germán; Yepez, Alfonso; Garcia, Luane Ferreira; Morais, Ruiter Lima; Vaz, Boniek Gontijo; Carvalho, Veronica Vale; de Oliveira, Gisele Augusto Rodrigues; Luque, Rafael; Gil, Eric De Souza

2017-02-01

Microcystin-leucine arginine (MC-LR) is the most abundant and toxic secondary metabolite produced by freshwater cyanobacteria. This toxin has a high potential hazard health due to potential interactions with liver, kidney and the nervous system. The aim of this work was the design of a simple and environmentally friendly electrochemical system based on highly efficient nanostructured electrodes for the removal of MC-LR in tap water. Titania nanoparticles were deposited on carbon (graphite) under a simple and efficient microwave assisted approach for the design of the electrode, further utilized in the electrochemical remediation assays. Parameters including the applied voltage, time of removal and pH (natural tap water or alkaline condition) were investigated in the process, with results pointing to a high removal efficiency for MC-LR (60% in tap water and 90% in alkaline media experiments, under optimized conditions).

Potential high efficiency solar cells: Applications from space photovoltaic research

NASA Technical Reports Server (NTRS)

Flood, D. J.

1986-01-01

NASA involvement in photovoltaic energy conversion research development and applications spans over two decades of continuous progress. Solar cell research and development programs conducted by the Lewis Research Center's Photovoltaic Branch have produced a sound technology base not only for the space program, but for terrestrial applications as well. The fundamental goals which have guided the NASA photovoltaic program are to improve the efficiency and lifetime, and to reduce the mass and cost of photovoltaic energy conversion devices and arrays for use in space. The major efforts in the current Lewis program are on high efficiency, single crystal GaAs planar and concentrator cells, radiation hard InP cells, and superlattice solar cells. A brief historical perspective of accomplishments in high efficiency space solar cells will be given, and current work in all of the above categories will be described. The applicability of space cell research and technology to terrestrial photovoltaics will be discussed.

High efficiency direct thermal to electric energy conversion from radioisotope decay using selective emitters and spectrally tuned solar cells

NASA Technical Reports Server (NTRS)

Chubb, Donald L.; Flood, Dennis J.; Lowe, Roland A.

1993-01-01

Thermophotovoltaic (TPV) systems are attractive possibilities for direct thermal-to-electric energy conversion, but have typically required the use of black body radiators operating at high temperatures. Recent advances in both the understanding and performance of solid rare-earth oxide selective emitters make possible the use of TPV at temperatures as low as 1200K. Both selective emitter and filter system TPV systems are feasible. However, requirements on the filter system are severe in order to attain high efficiency. A thin-film of a rare-earth oxide is one method for producing an efficient, rugged selective emitter. An efficiency of 0.14 and power density of 9.2 W/KG at 1200K is calculated for a hypothetical thin-film neodymia (Nd2O3) selective emitter TPV system that uses radioisotope decay as the thermal energy source.

Efficient electrochemical remediation of microcystin-LR in tap water using designer TiO2@carbon electrodes

PubMed Central

Sanz Lobón, Germán; Yepez, Alfonso; Garcia, Luane Ferreira; Morais, Ruiter Lima; Vaz, Boniek Gontijo; Carvalho, Veronica Vale; de Oliveira, Gisele Augusto Rodrigues; Luque, Rafael; Gil, Eric de Souza

2017-01-01

Microcystin-leucine arginine (MC-LR) is the most abundant and toxic secondary metabolite produced by freshwater cyanobacteria. This toxin has a high potential hazard health due to potential interactions with liver, kidney and the nervous system. The aim of this work was the design of a simple and environmentally friendly electrochemical system based on highly efficient nanostructured electrodes for the removal of MC-LR in tap water. Titania nanoparticles were deposited on carbon (graphite) under a simple and efficient microwave assisted approach for the design of the electrode, further utilized in the electrochemical remediation assays. Parameters including the applied voltage, time of removal and pH (natural tap water or alkaline condition) were investigated in the process, with results pointing to a high removal efficiency for MC-LR (60% in tap water and 90% in alkaline media experiments, under optimized conditions). PMID:28145477

Sustainable Production of o-Xylene from Biomass-Derived Pinacol and Acrolein.

PubMed

Hu, Yancheng; Li, Ning; Li, Guangyi; Wang, Aiqin; Cong, Yu; Wang, Xiaodong; Zhang, Tao

2017-07-21

o-Xylene (OX) is a large-volume commodity chemical that is conventionally produced from fossil fuels. In this study, an efficient and sustainable two-step route is used to produce OX from biomass-derived pinacol and acrolein. In the first step, the phosphotungstic acid (HPW)-catalyzed pinacol dehydration in 1-ethyl-3-methylimidazolium chloride ([emim]Cl) selectively affords 2,3-dimethylbutadiene. The high selectivity of this reaction can be ascribed to the H-bonding interaction between Cl - and the hydroxy group of pinacol. The stabilization of the carbocation intermediate by the surrounding anion Cl - may be another reason for the high selectivity. Notably, the good reusability of the HPW/[emim]Cl system can reduce the waste output and production cost. In the second step, OX is selectively produced by a Diels-Alder reaction of 2,3-dimethylbutadiene and acrolein, followed by a Pd/C-catalyzed decarbonylation/aromatization cascade in a one-pot fashion. The sustainable two-step process efficiently produces renewable OX in 79 % overall yield. Analogously, biomass-derived crotonaldehyde and pinacol can also serve as the feedstocks for the production of 1,2,4-trimethylbenzene. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Magnetic characterization of the stator core of a high-speed motor made of an ultrathin electrical steel sheet using the magnetic property evaluation system

NASA Astrophysics Data System (ADS)

Oka, Mohachiro; Enokizono, Masato; Mori, Yuji; Yamazaki, Kazumasa

2018-04-01

Recently, the application areas for electric motors have been expanding. For instance, electric motors are used in new technologies such as rovers, drones, cars, and robots. The motor used in such machinery should be small, high-powered, highly-efficient, and high-speed. In such motors, loss at high-speed rotation must be especially minimal. Eddy-current loss in the stator core is known to increase greatly during loss at high-speed rotation of the motor. To produce an efficient high-speed motor, we are developing a stator core for a motor using an ultrathin electrical steel sheet with only a small amount of eddy-current loss. Furthermore, the magnetic property evaluation for efficient, high-speed motor stator cores that use conventional commercial frequency is insufficient. Thus, we made a new high-speed magnetic property evaluation system to evaluate the magnetic properties of the efficient high-speed motor stator core. This system was composed of high-speed A/D converters, D/A converters, and a high-speed power amplifier. In experiments, the ultrathin electrical steel sheet dramatically suppressed iron loss and, in particular, eddy-current loss. In addition, a new high-speed magnetic property evaluation system accurately evaluated the magnetic properties of the efficient high-speed motor stator core.

Non-sterilized fermentation of high optically pure D-lactic acid by a genetically modified thermophilic Bacillus coagulans strain.

PubMed

Zhang, Caili; Zhou, Cheng; Assavasirijinda, Nilnate; Yu, Bo; Wang, Limin; Ma, Yanhe

2017-11-25

Optically pure D-lactic acid (≥ 99%) is an important precursor of polylactic acid. However, there are relatively few studies on D-lactic acid fermentation compared with the extensive investigation of L-lactic acid production. Most lactic acid producers are mesophilic organisms. Optically pure D-lactic acid produced at high temperature not only could reduce the costs of sterilization but also could inhibit the growth of other bacteria, such as L-lactic acid producers. Thermophilic Bacillus coagulans is an excellent producer of L-lactic acid with capable of growing at 50 °C. In our previous study, the roles of two L-lactic acid dehydrogenases have been demonstrated in B. coagulans DSM1. In this study, the function of another annotated possible L-lactate dehydrogenase gene (ldhL3) was verified to be leucine dehydrogenase with an activity of 0.16 units (μmol/min) per mg protein. Furthermore, the activity of native D-lactate dehydrogenase was too low to support efficient D-lactic acid production, even under the control of strong promoter. Finally, an engineered B. coagulans D-DSM1 strain with the capacity for efficient production of D-lactic acid was constructed by deletion of two L-lactate dehydrogenases genes (ldhL1 and ldhL2) and insertion of the D-lactate dehydrogenase gene (LdldhD) from Lactobacillus delbrueckii subsp. bulgaricus DSM 20081 at the position of ldhL1. This genetically engineered strain produced only D-lactic acid under non-sterilized condition, and finally 145 g/L of D-lactic acid was produced with an optical purity of 99.9% and a high yield of 0.98 g/g. This is the highest optically pure D-lactic acid titer produced by a thermophilic strain.

Vertically Aligned Graphene Sheets Membrane for Highly Efficient Solar Thermal Generation of Clean Water.

PubMed

Zhang, Panpan; Li, Jing; Lv, Lingxiao; Zhao, Yang; Qu, Liangti

2017-05-23

Efficient utilization of solar energy for clean water is an attractive, renewable, and environment friendly way to solve the long-standing water crisis. For this task, we prepared the long-range vertically aligned graphene sheets membrane (VA-GSM) as the highly efficient solar thermal converter for generation of clean water. The VA-GSM was prepared by the antifreeze-assisted freezing technique we developed, which possessed the run-through channels facilitating the water transport, high light absorption capacity for excellent photothermal transduction, and the extraordinary stability in rigorous conditions. As a result, VA-GSM has achieved average water evaporation rates of 1.62 and 6.25 kg m -2 h -1 under 1 and 4 sun illumination with a superb solar thermal conversion efficiency of up to 86.5% and 94.2%, respectively, better than that of most carbon materials reported previously, which can efficiently produce the clean water from seawater, common wastewater, and even concentrated acid and/or alkali solutions.

Innovative solar thermochemical water splitting.

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

Hogan, Roy E. Jr.; Siegel, Nathan P.; Evans, Lindsey R.

2008-02-01

Sandia National Laboratories (SNL) is evaluating the potential of an innovative approach for splitting water into hydrogen and oxygen using two-step thermochemical cycles. Thermochemical cycles are heat engines that utilize high-temperature heat to produce chemical work. Like their mechanical work-producing counterparts, their efficiency depends on operating temperature and on the irreversibility of their internal processes. With this in mind, we have invented innovative design concepts for two-step solar-driven thermochemical heat engines based on iron oxide and iron oxide mixed with other metal oxides (ferrites). The design concepts utilize two sets of moving beds of ferrite reactant material in close proximitymore » and moving in opposite directions to overcome a major impediment to achieving high efficiency--thermal recuperation between solids in efficient counter-current arrangements. They also provide inherent separation of the product hydrogen and oxygen and are an excellent match with high-concentration solar flux. However, they also impose unique requirements on the ferrite reactants and materials of construction as well as an understanding of the chemical and cycle thermodynamics. In this report the Counter-Rotating-Ring Receiver/Reactor/Recuperator (CR5) solar thermochemical heat engine and its basic operating principals are described. Preliminary thermal efficiency estimates are presented and discussed. Our ferrite reactant material development activities, thermodynamic studies, test results, and prototype hardware development are also presented.« less

Electrochemical sulfide removal and caustic recovery from spent caustic streams.

PubMed

Vaiopoulou, Eleni; Provijn, Thomas; Prévoteau, Antonin; Pikaar, Ilje; Rabaey, Korneel

2016-04-01

Spent caustic streams (SCS) are produced during alkaline scrubbing of sulfide containing sour gases. Conventional methods mainly involve considerable chemical dosing or energy expenditures entailing high cost but limited benefits. Here we propose an electrochemical treatment approach involving anodic sulfide oxidation preferentially to sulfur coupled to cathodic caustic recovery using a two-compartment electrochemical system. Batch experiments showed sulfide removal efficiencies of 84 ± 4% with concomitant 57 ± 4% efficient caustic production in the catholyte at a final concentration of 6.4 ± 0.1 wt% NaOH (1.6 M) at an applied current density of 100 A m(-2). Subsequent long-term continuous experiments showed that stable cell voltages (i.e. 2.7 ± 0.1 V) as well as constant sulfide removal efficiencies of 67 ± 5% at a loading rate of 47 g(S) L(-1) h(-1) were achieved over a period of 77 days. Caustic was produced at industrially relevant strengths for scrubbing (i.e. 5.1 ± 0.9 wt% NaOH) at current efficiencies of 96 ± 2%. Current density between 0 and 200 A m(-2) and sulfide loading rates of 50-200 g(S) L(-1) d(-1) were tested. The higher the current density the more oxidized the sulfur species produced and the higher the sulfide oxidation. On the contrary, high loading rate resulted in a reduction of sulfide oxidation efficiency. The results obtained in this study together with engineering calculations show that the proposed process could represent a cost-effective approach for sodium and sulfur recovery from SCS. Copyright © 2016 Elsevier Ltd. All rights reserved.

Forward-Osmosis Desalination with Poly(Ionic Liquid) Hydrogels as Smart Draw Agents.

PubMed

Fan, Xuelin; Liu, Huili; Gao, Yating; Zou, Zhu; Craig, Vincent S J; Zhang, Guangzhao; Liu, Guangming

2016-06-01

The combination of high desalination efficiency, negligible draw-solute leakage, nontoxicity, ease of regeneration, and effective separation to produce liquid water makes the smart draw agents developed here highly suited for forward-osmosis desalination. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Engineering cell factories for producing building block chemicals for bio-polymer synthesis.

PubMed

Tsuge, Yota; Kawaguchi, Hideo; Sasaki, Kengo; Kondo, Akihiko

2016-01-21

Synthetic polymers are widely used in daily life. Due to increasing environmental concerns related to global warming and the depletion of oil reserves, the development of microbial-based fermentation processes for the production of polymer building block chemicals from renewable resources is desirable to replace current petroleum-based methods. To this end, strains that efficiently produce the target chemicals at high yields and productivity are needed. Recent advances in metabolic engineering have enabled the biosynthesis of polymer compounds at high yield and productivities by governing the carbon flux towards the target chemicals. Using these methods, microbial strains have been engineered to produce monomer chemicals for replacing traditional petroleum-derived aliphatic polymers. These developments also raise the possibility of microbial production of aromatic chemicals for synthesizing high-performance polymers with desirable properties, such as ultraviolet absorbance, high thermal resistance, and mechanical strength. In the present review, we summarize recent progress in metabolic engineering approaches to optimize microbial strains for producing building blocks to synthesize aliphatic and high-performance aromatic polymers.

Method for enhancement of useful luminescence from vacancy defects in refractory oxides for tunable lasers

DOEpatents

Chen, Yok

1990-01-01

Refractory oxide crystals suitable for use in tunable lasers and a method for preparing the same are provided. The crystals are characterized by high quantum efficiency, high thermal stability, good crystal transparency, and a high percentage of useful luminescence. The method for preparation of the crystals involves removing substantially all the hydrogen, thermochemically reducing the crystal's oxygen content to produce oxygen (anion) vacancy defects, and subsequently irradiating the crystal with electrons to inactivate trace H.sup.- ions so that an increased amount of short lived F.sup.+ luminescence is produced when the crystal is optically excited.

Near atomically smooth alkali antimonide photocathode thin films

DOE PAGES

Feng, Jun; Karkare, Siddharth; Nasiatka, James; ...

2017-01-24

Nano-roughness is one of the major factors degrading the emittance of electron beams that can be generated by high efficiency photocathodes, such as the thermally reacted alkali antimonide thin films. In this paper, we demonstrate a co-deposition based method for producing alkali antimonide cathodes that produce near atomic smoothness with high reproducibility. Here, we calculate the effect of the surface roughness on the emittance and show that such smooth cathode surfaces are essential for operation of alkali antimonide cathodes in high field, low emittance radio frequency electron guns and to obtain ultracold electrons for ultrafast electron diffraction applications.

Near atomically smooth alkali antimonide photocathode thin films

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

Feng, Jun; Karkare, Siddharth; Nasiatka, James

Nano-roughness is one of the major factors degrading the emittance of electron beams that can be generated by high efficiency photocathodes, such as the thermally reacted alkali antimonide thin films. In this paper, we demonstrate a co-deposition based method for producing alkali antimonide cathodes that produce near atomic smoothness with high reproducibility. Here, we calculate the effect of the surface roughness on the emittance and show that such smooth cathode surfaces are essential for operation of alkali antimonide cathodes in high field, low emittance radio frequency electron guns and to obtain ultracold electrons for ultrafast electron diffraction applications.

Generation of high-field narrowband terahertz radiation by counterpropagating plasma wakefields

NASA Astrophysics Data System (ADS)

Timofeev, I. V.; Annenkov, V. V.; Volchok, E. P.

2017-10-01

It is found that nonlinear interaction of plasma wakefields driven by counterpropagating laser or particle beams can efficiently generate high-power electromagnetic radiation at the second harmonic of the plasma frequency. Using a simple analytical theory and particle-in-cell simulations, we show that this phenomenon can be attractive for producing high-field ( ˜10 MV/cm) tunable terahertz radiation with a narrow line width. For laser drivers produced by existing petawatt-class systems, this nonlinear process opens the way to the generation of gigawatt, multi-millijoule terahertz pulses which are not presently available for any other generating schemes.

Low-Cost Resin Transfer Molding Process Developed for High-Temperature Polyimide Matrix Composites

NASA Technical Reports Server (NTRS)

1996-01-01

The use of high-temperature polymer matrix composites (PMC's) in aircraft engine applications can significantly reduce engine weight and improve performance and fuel efficiency. High-temperature PMC's, such as those based on the PMR-15 polyimide matrix resin developed by the NASA Lewis Research Center, have been used extensively in military applications where performance improvements have justified their use regardless of the cost involved in producing the component. However, in commercial engines cost is a primary driver, and PMC components must be produced at costs comparable to those of the metal components that they will replace.

High-Efficiency Selective Electron Tunnelling in a Heterostructure Photovoltaic Diode.

PubMed

Jia, Chuancheng; Ma, Wei; Gu, Chunhui; Chen, Hongliang; Yu, Haomiao; Li, Xinxi; Zhang, Fan; Gu, Lin; Xia, Andong; Hou, Xiaoyuan; Meng, Sheng; Guo, Xuefeng

2016-06-08

A heterostructure photovoltaic diode featuring an all-solid-state TiO2/graphene/dye ternary interface with high-efficiency photogenerated charge separation/transport is described here. Light absorption is accomplished by dye molecules deposited on the outside surface of graphene as photoreceptors to produce photoexcited electron-hole pairs. Unlike conventional photovoltaic conversion, in this heterostructure both photoexcited electrons and holes tunnel along the same direction into graphene, but only electrons display efficient ballistic transport toward the TiO2 transport layer, thus leading to effective photon-to-electricity conversion. On the basis of this ipsilateral selective electron tunnelling (ISET) mechanism, a model monolayer photovoltaic device (PVD) possessing a TiO2/graphene/acridine orange ternary interface showed ∼86.8% interfacial separation/collection efficiency, which guaranteed an ultrahigh absorbed photon-to-current efficiency (APCE, ∼80%). Such an ISET-based PVD may become a fundamental device architecture for photovoltaic solar cells, photoelectric detectors, and other novel optoelectronic applications with obvious advantages, such as high efficiency, easy fabrication, scalability, and universal availability of cost-effective materials.

Monte Carlo simulations and measurements for efficiency determination of lead shielded plastic scintillator detectors

NASA Astrophysics Data System (ADS)

Yasin, Zafar; Negoita, Florin; Tabbassum, Sana; Borcea, Ruxandra; Kisyov, Stanimir

2017-12-01

The plastic scintillators are used in different areas of science and technology. One of the use of these scintillator detectors is as beam loss monitors (BLM) for new generation of high intensity heavy ion in superconducting linear accelerators. Operated in pulse counting mode with rather high thresholds and shielded by few centimeters of lead in order to cope with radiofrequency noise and X-ray background emitted by accelerator cavities, they preserve high efficiency for high energy gamma ray and neutrons produced in the nuclear reactions of lost beam particles with accelerator components. Efficiency calculation and calibration of detectors is very important before their practical usage. In the present work, the efficiency of plastic scintillator detectors is simulated using FLUKA for different gamma and neutron sources like, 60Co, 137Cs and 238Pu-Be. The sources are placed at different positions around the detector. Calculated values are compared with the measured values and a reasonable agreement is observed.

High-Efficiency Food Production in a Renewable Energy Based Micro-Grid Power System

NASA Technical Reports Server (NTRS)

Bubenheim, David; Meiners, Dennis

2016-01-01

Controlled Environment Agriculture (CEA) systems can be used to produce high-quality, desirable food year round, and the fresh produce can positively contribute to the health and well being of residents in communities with difficult supply logistics. While CEA has many positive outcomes for a remote community, the associated high electric demands have prohibited widespread implementation in what is typically already a fully subscribed power generation and distribution system. Recent advances in CEA technologies as well as renewable power generation, storage, and micro-grid management are increasing system efficiency and expanding the possibilities for enhancing community supporting infrastructure without increasing demands for outside supplied fuels. We will present examples of how new lighting, nutrient delivery, and energy management and control systems can enable significant increases in food production efficiency while maintaining high yields in CEA. Examples from Alaskan communities where initial incorporation of renewable power generation, energy storage and grid management techniques have already reduced diesel fuel consumption for electric generation by more than 40% and expanded grid capacity will be presented. We will discuss how renewable power generation, efficient grid management to extract maximum community service per kW, and novel energy storage approaches can expand the food production, water supply, waste treatment, sanitation and other community support services without traditional increases of consumable fuels supplied from outside the community. These capabilities offer communities with a range of choices to enhance their communities. The examples represent a synergy of technology advancement efforts to develop sustainable community support systems for future space-based human habitats and practical implementation of infrastructure components to increase efficiency and enhance health and well being in remote communities today and tomorrow.

High-Efficiency Food Production in a Renewable Energy Based Micro-Grid

NASA Technical Reports Server (NTRS)

Bubenheim, David L.

2017-01-01

Controlled Environment Agriculture (CEA) systems can be used to produce high-quality, desirable food year round, and the fresh produce can positively contribute to the health and well being of residents in communities with difficult supply logistics. While CEA has many positive outcomes for a remote community, the associated high electric demands have prohibited widespread implementation in what is typically already a fully subscribed power generation and distribution system. Recent advances in CEA technologies as well as renewable power generation, storage, and micro-grid management are increasing system efficiency and expanding the possibilities for enhancing community supporting infrastructure without increasing demands for outside supplied fuels. We will present examples of how new lighting, nutrient delivery, and energy management and control systems can enable significant increases in food production efficiency while maintaining high yields in CEA.Examples from Alaskan communities where initial incorporation of renewable power generation, energy storage and grid management techniques have already reduced diesel fuel consumption for electric generation by more than 40 and expanded grid capacity will be presented. We will discuss how renewable power generation, efficient grid management to extract maximum community service per kW, and novel energy storage approaches can expand the food production, water supply, waste treatment, sanitation and other community support services without traditional increases of consumable fuels supplied from outside the community. These capabilities offer communities with a range of choices to enhance their communities. The examples represent a synergy of technology advancement efforts to develop sustainable community support systems for future space-based human habitats and practical implementation of infrastructure components to increase efficiency and enhance health and well-being in remote communities today and tomorrow.

Realistic and efficient 2D crack simulation

NASA Astrophysics Data System (ADS)

Yadegar, Jacob; Liu, Xiaoqing; Singh, Abhishek

2010-04-01

Although numerical algorithms for 2D crack simulation have been studied in Modeling and Simulation (M&S) and computer graphics for decades, realism and computational efficiency are still major challenges. In this paper, we introduce a high-fidelity, scalable, adaptive and efficient/runtime 2D crack/fracture simulation system by applying the mathematically elegant Peano-Cesaro triangular meshing/remeshing technique to model the generation of shards/fragments. The recursive fractal sweep associated with the Peano-Cesaro triangulation provides efficient local multi-resolution refinement to any level-of-detail. The generated binary decomposition tree also provides efficient neighbor retrieval mechanism used for mesh element splitting and merging with minimal memory requirements essential for realistic 2D fragment formation. Upon load impact/contact/penetration, a number of factors including impact angle, impact energy, and material properties are all taken into account to produce the criteria of crack initialization, propagation, and termination leading to realistic fractal-like rubble/fragments formation. The aforementioned parameters are used as variables of probabilistic models of cracks/shards formation, making the proposed solution highly adaptive by allowing machine learning mechanisms learn the optimal values for the variables/parameters based on prior benchmark data generated by off-line physics based simulation solutions that produce accurate fractures/shards though at highly non-real time paste. Crack/fracture simulation has been conducted on various load impacts with different initial locations at various impulse scales. The simulation results demonstrate that the proposed system has the capability to realistically and efficiently simulate 2D crack phenomena (such as window shattering and shards generation) with diverse potentials in military and civil M&S applications such as training and mission planning.

Vacuum Nanohole Array Embedded Phosphorescent Organic Light Emitting Diodes

PubMed Central

Jeon, Sohee; Lee, Jeong-Hwan; Jeong, Jun-Ho; Song, Young Seok; Moon, Chang-Ki; Kim, Jang-Joo; Youn, Jae Ryoun

2015-01-01

Light extraction from organic light-emitting diodes that utilize phosphorescent materials has an internal efficiency of 100% but is limited by an external quantum efficiency (EQE) of 30%. In this study, extremely high-efficiency organic light emitting diodes (OLEDs) with an EQE of greater than 50% and low roll-off were produced by inserting a vacuum nanohole array (VNHA) into phosphorescent OLEDs (PhOLEDs). The resultant extraction enhancement was quantified in terms of EQE by comparing experimentally measured results with those produced from optical modeling analysis, which assumes the near-perfect electric characteristics of the device. A comparison of the experimental data and optical modeling results indicated that the VNHA extracts the entire waveguide loss into the air. The EQE obtained in this study is the highest value obtained to date for bottom-emitting OLEDs. PMID:25732061

Exploration on the technology for ozone reduction in urban sewage treatment

NASA Astrophysics Data System (ADS)

Yang, Min; Sun, Yi; Han, Zhicheng; Liu, Jun

2017-05-01

With the rapid development of China’s economy, urban water consumption is increasing. However, sewage treatment plants will produce large amounts of sludge after treatment of sewage. Generally, and the sludge treatment costs are relatively high. Therefore, the problem about how to deal with the sewage sludge becomes the hot issues. Municipal waste water treatment plant produces a lot of sludge. This paper summarized the abroad study of ozonation minimization technology. Introduction and discussion were made on the principle of ozonated efficiency of sludge minimization, the efficiency of sludge minimization and the relationship between efficiency and ozone dosage, as well the effect of return sludge ozonated on waste water treatment running and the sludge setting and the dewatering characteristic. The economic estimation was also made on this technology. It’s showed that sludge minimization technology exhibits extensive application foreground.

Pt-coated cylindrical micropatterned honeycomb Petri dishes as an efficient TCO-free counter electrode in liquid junction photovoltaic devices

NASA Astrophysics Data System (ADS)

Dao, Van-Duong; Bui, Van-Tien; Choi, Ho-Suk

2018-02-01

The Pt layer deposited on a cylindrical micro cavity patterned Petri dish, which is produced using a one-step solvent-immersion phase separation, is fabricated for the first time as an FTO-free counter electrode (CE) for dye-sensitized solar cells (DSCs). Due to the high specific active surface area of the Pt-deposited honeycomb substrate CE, the efficiency of the DSC using the developed CE substrate is enhanced by 14.5% compared with the device using a Pt-sputtered flat substrate. This design strategy has potential in fabricating highly efficient and low-cost CE materials with FTO-free substrates for DSCs.

Development of a nonazeotropic heat pump for crew hygiene water heating

NASA Technical Reports Server (NTRS)

Walker, David H.; Deming, Glenn I.

1991-01-01

A heat pump system is currently under development to produce hot water for crew hygiene on future manned space missions. The heat pump uses waste heat sources and a nonazeotropic working fluid in a highly efficient cycle. The potential benefits include a reduction in peak power draw from 2 to 5 kW for electric cartridge heaters to just more than 100 W for the heat pump. As part of the heat pump development project, a unique high efficiency compressor was developed to maintain lubrication in a zero-gravity environment.

Preliminary Ionization Efficiencies of {sup 11}C and {sup 14}O with the LBNL ECR Ion Sources

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

Xie, Z.Q.; Cerny, J.; Guo, F.Q.

1998-10-05

High charge states, up to fully stripped {sup 11}C and {sup 14}O ion, beams have been produced with the electron cyclotron resonance ion sources (LBNL, ECR and AECR-U) at Lawrence Berkeley National Laboratory. The radioactive atoms of {sup 11}C and {sup 14}O were collected in batch mode with an LN{sub 2} trap and then bled into the ECR ion sources. Ionization efficiency as high as 11% for {sup 11}C{sup 4+} was achieved.

A Highly Efficient and Facile Approach for Fabricating Graphite Nanoplatelets

NASA Astrophysics Data System (ADS)

Van Thanh, Dang; Van Thien, Nguyen; Thang, Bui Hung; Van Chuc, Nguyen; Hong, Nguyen Manh; Trang, Bui Thi; Lam, Tran Dai; Huyen, Dang Thi Thu; Hong, Phan Ngoc; Minh, Phan Ngoc

2016-05-01

In this study, we report a highly efficient, convenient, and cost-effective technique for producing graphite nanoplatelets (GNPs) from plasma-expanded graphite oxides (PEGOs) obtained directly from low-cost, recycled graphite electrodes of used batteries, x-ray diffraction, Raman spectroscopy, and x-ray photoelectron spectroscopy confirmed the successful preparation of GNPs. Scanning electron microscopy revealed that the GNPs have lateral width from several hundreds of nanometers to 1.5 μm with an approximate thickness of 20-50 nm. These GNPs can serve as a precursor for the preparation of GNPs-based nanocomposite.

Manipulating Adsorption-Insertion Mechanisms in Nanostructured Carbon Materials for High-Efficiency Sodium Ion Storage

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

Qiu, Shen; Xiao, Lifen; Sushko, Maria L.

Hard carbon is one of the most promising anode materials for sodium-ion batteries, but the low coulombic efficiency is still a key barrier. In this paper we synthesized a series of nanostructured hard carbon materials with controlled architectures. Using a combination of in-situ XRD mapping, ex-situ NMR, EPR, electrochemical techniques and simulations, an “adsorption-intercalation” (A-I) mechanism is established for Na ion storage. During the initial stages of Na insertion, Na ions adsorb on the defect sites of hard carbon with a wide adsorption energy distribution, producing a sloping voltage profile. In the second stage, Na ions intercalate into graphitic layersmore » with suitable spacing to form NaCx compounds similar to the Li ion intercalation process in graphite, producing a flat low voltage plateau. The cation intercalation with a flat voltage plateau should be enhanced and the sloping region should be avoided. Guided by this knowledge, non-porous hard carbon material has been developed which has achieved high reversible capacity and coulombic efficiency to fulfill practical application.« less

Production, Characterization, and Flocculation Mechanism of Cation Independent, pH Tolerant, and Thermally Stable Bioflocculant from Enterobacter sp. ETH-2

PubMed Central

Tang, Wei; Song, Liyan; Li, Dou; Qiao, Jing; Zhao, Tiantao; Zhao, Heping

2014-01-01

Synthetic high polymer flocculants, frequently utilized for flocculating efficiency and low cost, recently have been discovered as producing increased risk to human health and the environment. Development of a more efficient and environmentally sound alternative flocculant agent is investigated in this paper. Bioflocculants are produced by microorganisms and may exhibit a high rate of flocculation activity. The bioflocculant ETH-2, with high flocculating activity (2849 mg Kaolin particle/mg ETH-2), produced by strain Enterobacter sp. isolated from activated sludge, was systematically investigated with regard to its production, characterization, and flocculation mechanism. Analyses of microscopic observation, zeta potential and ETH-2 structure demonstrates the bridging mechanism, as opposed to charge neutralization, was responsible for flocculation of the ETH-2. ETH-2 retains high molecular weight (603 to 1820 kDa) and multi-functional groups (hydroxyl, amide and carboxyl) that contributed to flocculation. Polysaccharides mainly composed of mannose, glucose, and galactose, with a molar ratio of 1∶2.9∶9.8 were identified as the active constituents in bioflocculant. The structure of the long backbone with active sites of polysaccharides was determined as a primary basis for the high flocculation activity. Bioflocculant ETH-2 is cation independent, pH tolerant, and thermally stable, suggesting a potential fit for industrial application. PMID:25485629

10 GHz dual loop opto-electronic oscillator without RF-amplifiers

NASA Astrophysics Data System (ADS)

Zhou, Weimin; Okusaga, Olukayode; Nelson, Craig; Howe, David; Carter, Gary

2008-02-01

We report the first demonstration of a 10 GHz dual-fiber-loop Opto-Electronic Oscillator (OEO) without RF-amplifiers. Using a recently developed highly efficient RF-Photonic link with RF-to-RF gain facilitated by a high power laser, highly efficient optical modulator and high power phototectectors, we have built an amplifier-less OEO that eliminates the phase noise produced by the electronic amplifier. The dual-loop approach can provide additional gain and reduce unwanted multi-mode spurs. However, we have observed RF phase noise produced by the high power laser include relative intensity noise (RIN) and noise related to the laser's electronic control system. In addition, stimulated Brillouin scattering limits the fiber loop's length to ~2km at the 40mW laser power needed to provide the RF gain which limits the system's quality factor, Q. We have investigated several different methods for solving these problems. One promising technique is the use of a multi-longitudinal-mode laser to carry the RF signal, maintaining the total optical power but reducing the optical power of each mode to eliminate the Brillouin scattering in a longer fiber thereby reducing the phase noise of the RF signal produced by the OEO. This work shows that improvement in photonic components increases the potential for more RF system applications such as an OEO's with higher performance and new capabilities.

Scanning electron microscope image signal-to-noise ratio monitoring for micro-nanomanipulation.

PubMed

Marturi, Naresh; Dembélé, Sounkalo; Piat, Nadine

2014-01-01

As an imaging system, scanning electron microscope (SEM) performs an important role in autonomous micro-nanomanipulation applications. When it comes to the sub micrometer range and at high scanning speeds, the images produced by the SEM are noisy and need to be evaluated or corrected beforehand. In this article, the quality of images produced by a tungsten gun SEM has been evaluated by quantifying the level of image signal-to-noise ratio (SNR). In order to determine the SNR, an efficient and online monitoring method is developed based on the nonlinear filtering using a single image. Using this method, the quality of images produced by a tungsten gun SEM is monitored at different experimental conditions. The derived results demonstrate the developed method's efficiency in SNR quantification and illustrate the imaging quality evolution in SEM. © 2014 Wiley Periodicals, Inc.

Facile synthesis of semi-library of low charge density cationic polyesters from poly(alkylene maleate)s for efficient local gene delivery.

PubMed

Yan, Huijie; Zhu, Dingcheng; Zhou, Zhuxian; Liu, Xin; Piao, Ying; Zhang, Zhen; Liu, Xiangrui; Tang, Jianbin; Shen, Youqing

2018-03-30

Cationic polymers are one of the main non-viral vectors for gene therapy, but their applications are hindered by the toxicity and inefficient transfection, particularly in the presence of serum or other biological fluids. While rational design based on the current understanding of gene delivery process has produced various cationic polymers with improved overall transfection, high-throughput parallel synthesis of libraries of cationic polymers seems a more effective strategy to screen out efficacious polymers. Herein, we demonstrate a novel platform for parallel synthesis of low cationic charge-density polyesters for efficient gene delivery. Unsaturated polyester poly(alkylene maleate) (PAM) readily underwent Michael-addition reactions with various mercaptamines to produce polyester backbones with pendant amine groups, poly(alkylene maleate mercaptamine)s (PAMAs). Variations of the alkylenes in the backbone and the mercaptamines on the side chain produced PAMAs with tunable hydrophobicity and DNA-condensation ability, the key parameters dominating transfection efficiency of the resulting polymer/DNA complexes (polyplexes). A semi-library of such PAMAs was exampled from 7 alkylenes and 18 mercaptamines, from which a lead PAMA, G-1, synthesized from poly(1,4-phenylene bis(methylene) maleate) and N,N-dimethylcysteamine, showed remarkable transfection efficiency even in the presence of serum, owing to its efficient lysosome-circumventing cellular uptake. Furthermore, G-1 polyplexes efficiently delivered the suicide gene pTRAIL to intraperitoneal tumors and elicited effective anticancer activity. Copyright © 2018 Elsevier Ltd. All rights reserved.

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

Bustamante, Mauricio; Heinze, Jonas; Winter, Walter

Gamma-ray bursts (GRBs) are promising as sources of neutrinos and cosmic rays. In the internal shock scenario, blobs of plasma emitted from a central engine collide within a relativistic jet and form shocks, leading to particle acceleration and emission. Motivated by present experimental constraints and sensitivities, we improve the predictions of particle emission by investigating time-dependent effects from multiple shocks. We produce synthetic light curves with different variability timescales that stem from properties of the central engine. For individual GRBs, qualitative conclusions about model parameters, neutrino production efficiency, and delays in high-energy gamma-rays can be deduced from inspection of themore » gamma-ray light curves. GRBs with fast time variability without additional prominent pulse structure tend to be efficient neutrino emitters, whereas GRBs with fast variability modulated by a broad pulse structure can be inefficient neutrino emitters and produce delayed high-energy gamma-ray signals. Our results can be applied to quantitative tests of the GRB origin of ultra-high-energy cosmic rays, and have the potential to impact current and future multi-messenger searches.« less

From photons to biomass and biofuels: evaluation of different strategies for the improvement of algal biotechnology based on comparative energy balances.

PubMed

Wilhelm, Christian; Jakob, Torsten

2011-12-01

Microalgal based biofuels are discussed as future sustainable energy source because of their higher photosynthetic and water use efficiency to produce biomass. In the context of climate CO2 mitigation strategies, algal mass production is discussed as a potential CO2 sequestration technology which uses CO2 emissions to produce biomass with high-oil content independent on arable land. In this short review, it is presented how complete energy balances from photon to harvestable biomass can help to identify the limiting processes on the cellular level. The results show that high productivity is always correlated with high metabolic costs. The overall efficiency of biomass formation can be improved by a photobioreactor design which is kinetically adapted to the rate-limiting steps in cell physiology. However, taking into account the real photon demand per assimilated carbon and the energy input for biorefinement, it becomes obvious that alternative strategies must be developed to reach the goal of a real CO2 sequestration.

Conceptual Design of Low-Temperature Hydrogen Production and High-Efficiency Nuclear Reactor Technology

NASA Astrophysics Data System (ADS)

Fukushima, Kimichika; Ogawa, Takashi

Hydrogen, a potential alternative energy source, is produced commercially by methane (or LPG) steam reforming, a process that requires high temperatures, which are produced by burning fossil fuels. However, as this process generates large amounts of CO2, replacement of the combustion heat source with a nuclear heat source for 773-1173K processes has been proposed in order to eliminate these CO2 emissions. In this paper, a novel method of nuclear hydrogen production by reforming dimethyl ether (DME) with steam at about 573K is proposed. From a thermodynamic equilibrium analysis of DME steam reforming, the authors identified conditions that provide high hydrogen production fraction at low pressure and temperatures of about 523-573K. By setting this low-temperature hydrogen production process upstream from a turbine and nuclear reactor at about 573K, the total energy utilization efficiency according to equilibrium mass and heat balance analysis is about 50%, and it is 75%for a fast breeder reactor (FBR), where turbine is upstream of the reformer.

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

Buckpitt, Alan, E-mail: arbuckpitt@ucdavis.edu; Morin, Dexter; Murphy, Shannon

Naphthalene produces species and cell selective injury to respiratory tract epithelial cells of rodents. In these studies we determined the apparent K{sub m}, V{sub max}, and catalytic efficiency (V{sub max}/K{sub m}) for naphthalene metabolism in microsomal preparations from subcompartments of the respiratory tract of rodents and non-human primates. In tissues with high substrate turnover, major metabolites were derived directly from naphthalene oxide with smaller amounts from conjugates of diol epoxide, diepoxide, and 1,2- and 1,4-naphthoquinones. In some tissues, different enzymes with dissimilar K{sub m} and V{sub max} appeared to metabolize naphthalene. The rank order of V{sub max} (rat olfactory epitheliummore » > mouse olfactory epithelium > murine airways ≫ rat airways) correlated well with tissue susceptibility to naphthalene. The V{sub max} in monkey alveolar subcompartment was 2% that in rat nasal olfactory epithelium. Rates of metabolism in nasal compartments of the monkey were low. The catalytic efficiencies of microsomes from known susceptible tissues/subcompartments are 10 and 250 fold higher than in rat airway and monkey alveolar subcompartments, respectively. Although the strong correlations between catalytic efficiencies and tissue susceptibility suggest that non-human primate tissues are unlikely to generate metabolites at a rate sufficient to produce cellular injury, other studies showing high levels of formation of protein adducts support the need for additional studies. - Highlights: • Naphthalene is metabolized with high catalytic efficiency in susceptible tissue. • Naphthalene is metabolized at low catalytic efficiency in non-susceptible tissue. • Respiratory tissues of the non human primate metabolize naphthalene slowly.« less

High-Efficiency InGaN/GaN Quantum Well-Based Vertical Light-Emitting Diodes Fabricated on β-Ga2O3 Substrate.

PubMed

Muhammed, Mufasila M; Alwadai, Norah; Lopatin, Sergei; Kuramata, Akito; Roqan, Iman S

2017-10-04

We demonstrate a state-of-the-art high-efficiency GaN-based vertical light-emitting diode (VLED) grown on a transparent and conductive (-201)-oriented (β-Ga 2 O 3 ) substrate, obtained using a straightforward growth process that does not require a high-cost lift-off technique or complex fabrication process. The high-resolution scanning transmission electron microscopy (STEM) images confirm that we produced high quality upper layers, including a multiquantum well (MQW) grown on the masked β-Ga 2 O 3 substrate. STEM imaging also shows a well-defined MQW without InN diffusion into the barrier. Electroluminescence (EL) measurements at room temperature indicate that we achieved a very high internal quantum efficiency (IQE) of 78%; at lower temperatures, IQE reaches ∼86%. The photoluminescence (PL) and time-resolved PL analysis indicate that, at a high carrier injection density, the emission is dominated by radiative recombination with a negligible Auger effect; no quantum-confined Stark effect is observed. At low temperatures, no efficiency droop is observed at a high carrier injection density, indicating the superior VLED structure obtained without lift-off processing, which is cost-effective for large-scale devices.

Improvement in adenoviral gene transfer efficiency after preincubation at +37 degrees C in vitro and in vivo.

PubMed

Kossila, Maija; Jauhiainen, Suvi; Laukkanen, Mikko O; Lehtolainen, Pauliina; Jääskeläinen, Maiju; Turunen, Päivi; Loimas, Sami; Wahlfors, Jarmo; Ylä-Herttuala, Seppo

2002-01-01

Adenovirus is a widely used vector in gene transfer experiments because it produces high transduction efficiency in vitro and in vivo by means of the coxsackie-adenovirus receptor (CAR) and major histocompatibility complex (MHC) class I alpha-2 domain. Adenoviral gene transfer efficiency has been reported to correlate with cellular CAR expression. We report here a simple method to increase adenoviral gene transfer efficiency in cells that do not express high levels of CAR: preincubation of adenovirus for 30-40 minutes at +37 degrees C significantly increased the transduction efficiency in vitro in CHO and BALB/3T3 cells, in which CAR is expressed at very low levels. Increased transduction efficiency of preincubated adenovirus was also detected in vivo in rat brain tissue. In addition, we found that adenoviruses were rapidly inactivated in human serum in a complement-independent manner, whereas fetal bovine serum (FBS) had hardly any effects on the viral infectivity. We conclude that preincubation of adenoviral vectors at +37 degrees C may substantially increase gene transfer efficiency in applications in which target cells do not express high levels of CAR.

Processing of transparent polycrystalline AlON:Ce 3+ scintillators

DOE PAGES

Chen, Ching -Fong; Yang, Pin; King, Graham; ...

2015-10-23

A new polycrystalline ceramic scintillator is reported for potential use in radiation detection and medical imaging applications. The goal was to develop cerium-activated aluminum oxynitride (AlON:Ce 3+) ceramics, which can be produced using ceramic processes in comparison to the high-cost, low-yield single-crystal growth technique. A phase pure AlON:Ce 3+ powder with cubic symmetry was successfully synthesized at high temperature under a reducing atmosphere to convert Ce 4+ to Ce 3+ in the solid solution. We explored two different activator concentrations (0.5 and 1.0 mol%). Fully dense and transparent AlON:Ce 3+ ceramics were produced by a liquid-phase-assisted pressureless sintering. The crystalmore » field splitting around the Ce 3+ activator in the AlON was comparable to the splitting induced by Br₋ and the Cl₋ ligands, which produced an emission spectrum perfectly matching the maximum quantum efficiency range of the photomultiplier tube for radiation detection. Both optical excitation and radiation ionizations in AlON:Ce 3+ were demonstrated. Lastly, challenges and mechanisms related to the radioluminescence efficiency are discussed.« less

Overproduction of α-Lipoic Acid by Gene Manipulated Escherichia coli

PubMed Central

Sun, Yirong; Zhang, Wenbin; Ma, Jincheng; Pang, Hongshen; Wang, Haihong

2017-01-01

Alpha-lipoic acid (LA) is an important enzyme cofactor widely used by organisms and is also a natural antioxidant for the treatment of pathologies driven by low levels of endogenous antioxidants. In order to establish a safer and more efficient process for LA production, we developed a new biological method for LA synthesis based on the emerging knowledge of lipoic acid biosynthesis. We first cloned the lipD gene, which encodes the lipoyl domain of the E2 subunit of pyruvate dehydrogenase, allowing high levels of LipD production. Plasmids containing genes for the biosynthesis of LA were subsequently constructed utilizing various vectors and promotors to produce high levels of LA. These plasmids were transformed into the Escherichia coli strain BL21. Octanoic acid (OA) was used as the substrate for LA synthesis. One transformant, YS61, which carried lipD, lplA, and lipA, produced LA at levels over 200-fold greater than the wild-type strain, showing that LA could be produced efficiently in E. coli using genetic engineering methods. PMID:28068366

Ethanol production from lignocellulosic hydrolysates using engineered Saccharomyces cerevisiae harboring xylose isomerase-based pathway.

PubMed

Ko, Ja Kyong; Um, Youngsoon; Woo, Han Min; Kim, Kyoung Heon; Lee, Sun-Mi

2016-06-01

The efficient co-fermentation of glucose and xylose is necessary for the economically feasible bioethanol production from lignocellulosic biomass. Even with xylose utilizing Saccharomyces cerevisiae, the efficiency of the lignocellulosic ethanol production remains suboptimal mainly due to the low conversion yield of xylose to ethanol. In this study, we evaluated the co-fermentation performances of SXA-R2P-E, a recently engineered isomerase-based xylose utilizing strain, in mixed sugars and in lignocellulosic hydrolysates. In a high-sugar fermentation with 70g/L of glucose and 40g/L of xylose, SXA-R2P-E produced 50g/L of ethanol with an yield of 0.43gethanol/gsugars at 72h. From dilute acid-pretreated hydrolysates of rice straw and hardwood (oak), the strain produced 18-21g/L of ethanol with among the highest yield of 0.43-0.46gethanol/gsugars ever reported. This study shows a highly promising potential of a xylose isomerase-expressing strain as an industrially relevant ethanol producer from lignocellulosic hydrolysates. Copyright © 2016 Elsevier Ltd. All rights reserved.

Beef donor cows with high number of retrieved COC produce more in vitro embryos compared with cows with low number of COC after repeated ovum pick-up sessions.

PubMed

Monteiro, F M; Batista, E O S; Vieira, L M; Bayeux, B M; Accorsi, M; Campanholi, S P; Dias, E A R; Souza, A H; Baruselli, P S

2017-03-01

The aim of the present study was to evaluate whether repeated ovum pick-up (OPU) procedures may affect the efficiency of OPU programs for in vitro embryo production (IVEP) in Bos indicus (Nelore) donors. In addition, the repeatability (r) efficiency of IVEP was also assessed. Data available were from 432 OPU-IVEP sessions that were performed at random stages of the estrous cycle in 36 cycling, nonlactating Nelore donors. Semen from three Nelore bulls was used for the IVF. Donors were submitted to 12 consecutive OPU procedures, with an interval of approximately 30 days between sessions. Data were analyzed as repeated measures using the GLIMMIX procedure of SAS 9.3. Cows yielding ≥15 COCs were defined as "high" COCs and cows with less than 15 COCs were defined as "low" COCs donors. The number of COCs retrieved decreased over time in donors classified with high COCs and remained fairly steady in cows with low COCs at the beginning of the program (P session*COC retrieved groups  = 0.02). Moreover, the number of COCs retrieved (P < 0.0001), and number of blastocysts produced per OPU (P = 0.001) was greater for the high COCs donors compared with the low COCs category, and these results were consistent across OPU sessions. Interestingly, there was no effect of COCs category on the rate of blastocyst development (P = 0.83). In addition, number of blastocysts produced were not affected by repeated OPU (P = 0.37) and interactions between time and COC category (P = 0.72). Similarly, blastocyst rate was not affected by repeated OPU (P = 0.21) and interactions between time and COC category (P = 0.58). Despite of COC category of the donor cows, repeatability was high for the number of COCs retrieved (r = 0.81), number of blastocysts produced per OPU (r = 0.79), and blastocyst rate (0.69). In conclusion, overall numbers of COCs decreased over time in donors classified as having high COCs. However, cumulative amounts of produced blastocysts were greater in donors with high COCs. More importantly, high repeatability was observed in terms of IVEP efficiency. Therefore, IVEP programs can be significantly improved with more aggressive selection toward donors with greater numbers of COCs. Copyright © 2016 Elsevier Inc. All rights reserved.

Disclosing the Parameters Leading to High Productivity of Retroviral Producer Cells Lines: Evaluating Random Versus Targeted Integration.

PubMed

Bandeira, Vanessa S; Tomás, Hélio A; Alici, Evren; Carrondo, Manuel J T; Coroadinha, Ana S

2017-04-01

Gammaretrovirus and lentivirus are the preferred viral vectors to genetically modify T and natural killer cells to be used in immune cell therapies. The transduction efficiency of hematopoietic and T cells is more efficient using gibbon ape leukemia virus (GaLV) pseudotyping. In this context gammaretroviral vector producer cells offer competitive higher titers than transient lentiviral vectors productions. The main aim of this work was to identify the key parameters governing GaLV-pseudotyped gammaretroviral vector productivity in stable producer cells, using a retroviral vector expression cassette enabling positive (facilitating cell enrichment) and negative cell selection (allowing cell elimination). The retroviral vector contains a thymidine kinase suicide gene fused with a ouabain-resistant Na + ,K + -ATPase gene, a potential safer and faster marker. The establishment of retroviral vector producer cells is traditionally performed by randomly integrating the retroviral vector expression cassette codifying the transgene. More recently, recombinase-mediated cassette exchange methodologies have been introduced to achieve targeted integration. Herein we compared random and targeted integration of the retroviral vector transgene construct. Two retroviral producer cell lines, 293 OuaS and 293 FlexOuaS, were generated by random and targeted integration, respectively, producing high titers (on the order of 10 7 infectious particles·ml -1 ). Results showed that the retroviral vector transgene cassette is the key retroviral vector component determining the viral titers notwithstanding, single-copy integration is sufficient to provide high titers. The expression levels of the three retroviral constructs (gag-pol, GaLV env, and retroviral vector transgene) were analyzed. Although gag-pol and GaLV env gene expression levels should surpass a minimal threshold, we found that relatively modest expression levels of these two expression cassettes are required. Their levels of expression should not be maximized. We concluded, to establish a high producer retroviral vector cell line only the expression level of the genomic retroviral RNA, that is, the retroviral vector transgene cassette, should be maximized, both through (1) the optimization of its design (i.e., genetic elements composition) and (2) the selection of high expressing chromosomal locus for its integration. The use of methodologies identifying and promoting integration into high-expression loci, as targeted integration or high-throughput screening are in this perspective highly valuable.

Highly efficient and autocatalytic H2₂ dissociation for CO₂ reduction into formic acid with zinc.

PubMed

Jin, Fangming; Zeng, Xu; Liu, Jianke; Jin, Yujia; Wang, Lunying; Zhong, Heng; Yao, Guodong; Huo, Zhibao

2014-03-28

Artificial photosynthesis, specifically H2O dissociation for CO2 reduction with solar energy, is regarded as one of the most promising methods for sustainable energy and utilisation of environmental resources. However, a highly efficient conversion still remains extremely challenging. The hydrogenation of CO2 is regarded as the most commercially feasible method, but this method requires either exotic catalysts or high-purity hydrogen and hydrogen storage, which are regarded as an energy-intensive process. Here we report a highly efficient method of H2O dissociation for reducing CO2 into chemicals with Zn powder that produces formic acid with a high yield of approximately 80%, and this reaction is revealed for the first time as an autocatalytic process in which an active intermediate, ZnH(-) complex, serves as the active hydrogen. The proposed process can assist in developing a new concept for improving artificial photosynthetic efficiency by coupling geochemistry, specifically the metal-based reduction of H2O and CO2, with solar-driven thermochemistry for reducing metal oxide into metal.

Highly efficient and autocatalytic H2O dissociation for CO2 reduction into formic acid with zinc

PubMed Central

Jin, Fangming; Zeng, Xu; Liu, Jianke; Jin, Yujia; Wang, Lunying; Zhong, Heng; Yao, Guodong; Huo, Zhibao

2014-01-01

Artificial photosynthesis, specifically H2O dissociation for CO2 reduction with solar energy, is regarded as one of the most promising methods for sustainable energy and utilisation of environmental resources. However, a highly efficient conversion still remains extremely challenging. The hydrogenation of CO2 is regarded as the most commercially feasible method, but this method requires either exotic catalysts or high-purity hydrogen and hydrogen storage, which are regarded as an energy-intensive process. Here we report a highly efficient method of H2O dissociation for reducing CO2 into chemicals with Zn powder that produces formic acid with a high yield of approximately 80%, and this reaction is revealed for the first time as an autocatalytic process in which an active intermediate, ZnH− complex, serves as the active hydrogen. The proposed process can assist in developing a new concept for improving artificial photosynthetic efficiency by coupling geochemistry, specifically the metal-based reduction of H2O and CO2, with solar-driven thermochemistry for reducing metal oxide into metal. PMID:24675820

Nanocellulose-Based Materials for Water Purification

PubMed Central

Voisin, Hugo; Bergström, Lennart; Liu, Peng; Mathew, Aji P.

2017-01-01

Nanocellulose is a renewable material that combines a high surface area with high strength, chemical inertness, and versatile surface chemistry. In this review, we will briefly describe how nanocellulose is produced, and present—in particular, how nanocellulose and its surface modified versions affects the adsorption behavior of important water pollutants, e.g., heavy metal species, dyes, microbes, and organic molecules. The processing of nanocellulose-based membranes and filters for water purification will be described in detail, and the uptake capacity, selectivity, and removal efficiency will also be discussed. The processing and performance of nanocellulose-based membranes, which combine a high removal efficiency with anti-fouling properties, will be highlighted. PMID:28336891

Apparatus and process for the separation of hydrophobic and hydrophilic particles using microbubble column flotation together with a process and apparatus for generation of microbubbles

DOEpatents

Yoon, R.H.; Adel, G.T.; Luttrell, G.H.

1992-12-01

A method and apparatus are disclosed for the microbubble flotation separation of very fine and coarse particles, especially coal and minerals, so as to produce high purity and high recovery efficiency. This is accomplished through the use of a flotation column, microbubbles, recycling of the flotation pulp, and countercurrent wash water to gently wash the froth. Also disclosed are unique processes and apparatus for generating microbubbles for flotation in a highly efficient and inexpensive manner using either a porous tube or in-line static generators. 14 figs.

Harmonic engine

DOEpatents

Bennett, Charles L [Livermore, CA

2009-10-20

A high efficiency harmonic engine based on a resonantly reciprocating piston expander that extracts work from heat and pressurizes working fluid in a reciprocating piston compressor. The engine preferably includes harmonic oscillator valves capable of oscillating at a resonant frequency for controlling the flow of working fluid into and out of the expander, and also preferably includes a shunt line connecting an expansion chamber of the expander to a buffer chamber of the expander for minimizing pressure variations in the fluidic circuit of the engine. The engine is especially designed to operate with very high temperature input to the expander and very low temperature input to the compressor, to produce very high thermal conversion efficiency.

Do photovoltaics have a future

NASA Technical Reports Server (NTRS)

Williams, B. F.

1979-01-01

There is major concern as to the economic practicality of widespread terrestrial use because of the high cost of the photovoltaic arrays themselves. Based on their high efficiency, photovoltaic collectors should be one of the cheapest forms of energy generators known. Present photovoltaic panels are violating the trend of lower costs with increasing efficiency due to their reliance on expensive materials. A medium technology solution should provide electricity competitive with the existing medium to high technology energy generators such as oil, coal, gas, and nuclear fission thermal plants. Programs to reduce the cost of silicon and develop reliable thin film materials have a realistic chance of producing cost effective photovoltaic panels.

Apparatus and process for the separation of hydrophobic and hydrophilic particles using microbubble column flotation together with a process and apparatus for generation of microbubbles

DOEpatents

Yoon, R.H.; Adel, G.T.; Luttrell, G.H.

1998-09-29

A method and apparatus are disclosed for the microbubble flotation separation of very fine and coarse particles, especially coal and minerals, so as to produce high purity and high recovery efficiency. This is accomplished through the use of a flotation column, microbubbles, recycling of the flotation pulp, and countercurrent wash water to gently wash the froth. Also disclosed are unique processes and apparatus for generating microbubbles for flotation in a highly efficient and inexpensive manner using either a porous tube or in-line static generators. 14 figs.

Two-Color Laser High-Harmonic Generation in Cavitated Plasma Wakefields

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

Schroeder, Carl; Benedetti, Carlo; Esarey, Eric

2016-10-03

A method is proposed for producing coherent x-rays via high-harmonic generation using a laser interacting with highly-stripped ions in cavitated plasma wakefields. Two laser pulses of different colors are employed: a long-wavelength pulse for cavitation and a short-wavelength pulse for harmonic generation. This method enables efficient laser harmonic generation in the sub-nm wavelength regime.

Tar-free fuel gas production from high temperature pyrolysis of sewage sludge

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

Zhang, Leguan; Xiao, Bo; Hu, Zhiquan

2014-01-15

Highlights: • High temperature pyrolysis of sewage sludge was efficient for producing tar-free fuel gas. • Complete tar removal and volatile matter release were at elevated temperature of 1300 °C. • Sewage sludge was converted to residual solid with high ash content. • 72.60% of energy conversion efficiency for gas production in high temperature pyrolysis. • Investment and costing for tar cleaning were reduced. - Abstract: Pyrolysis of sewage sludge was studied in a free-fall reactor at 1000–1400 °C. The results showed that the volatile matter in the sludge could be completely released to gaseous product at 1300 °C. Themore » high temperature was in favor of H{sub 2} and CO in the produced gas. However, the low heating value (LHV) of the gas decreased from 15.68 MJ/N m{sup 3} to 9.10 MJ/N m{sup 3} with temperature increasing from 1000 °C to 1400 °C. The obtained residual solid was characterized by high ash content. The energy balance indicated that the most heating value in the sludge was in the gaseous product.« less

An enhanced chemoenzymatic method for loading substrates onto carrier protein domains.

PubMed

Kittilä, Tiia; Cryle, Max J

2018-06-01

Non-ribosomal peptide synthetase (NRPS) machineries produce many medically relevant peptides that cannot be easily accessed by chemical synthesis. Thus, understanding NRPS mechanism is of crucial importance to allow efficient redesign of these machineries to produce new compounds. During NRPS-mediated synthesis, substrates are covalently attached to peptidyl carrier proteins (PCPs), and studies of NRPSs are impeded by difficulties in producing PCPs loaded with substrates. Different approaches to load substrates onto PCP domains have been described, but all suffer from difficulties in either the complexity of chemical synthesis or low enzymatic efficiency. Here, we describe an enhanced chemoenzymatic loading method that combines 2 approaches into a single, highly efficient one-pot loading reaction. First, d-pantetheine and ATP are converted into dephospho-coenzyme A via the actions of 2 enzymes from coenzyme A (CoA) biosynthesis. Next, phosphoadenylates are dephosphorylated using alkaline phosphatase to allow linker attachment to PCP domain by Sfp mutant R4-4, which is inhibited by phosphoadenylates. This route does not depend on activity of the commonly problematic dephospho-CoA kinase and, therefore, offers an improved method for substrate loading onto PCP domains.

Gasification of rice straw in a fluidized-bed gasifier for syngas application in close-coupled boiler-gasifier systems.

PubMed

Calvo, L F; Gil, M V; Otero, M; Morán, A; García, A I

2012-04-01

The feasibility and operation performance of the gasification of rice straw in an atmospheric fluidized-bed gasifier was studied. The gasification was carried out between 700 and 850 °C. The stoichiometric air-fuel ratio (A/F) for rice straw was 4.28 and air supplied was 7-25% of that necessary for stoichiometric combustion. Mass and power balances, tar concentration, produced gas composition, gas phase ammonia, chloride and potassium concentrations, agglomeration tendencies and gas efficiencies were assessed. Agglomeration was avoided by replacing the normal alumina-silicate bed by a mixture of alumina-silicate sand and MgO. It was shown that it is possible to produce high quality syngas from the gasification of rice straw. Under the experimental conditions used, the higher heating value (HHV) of the produced gas reached 5.1 MJ Nm(-3), the hot gas efficiency 61% and the cold gas efficiency 52%. The obtained results prove that rice straw may be used as fuel for close-coupled boiler-gasifier systems. Copyright © 2012 Elsevier Ltd. All rights reserved.

Alternative Fuels Data Center: Hydrogen Basics

Science.gov Websites

; Incentives Hydrogen Basics Hydrogen (H2) is an alternative fuel that can be produced from diverse domestic for domestic production, its fast filling time, and the fuel cell's high efficiency. In fact, a fuel

LEDs are on a roll

NASA Astrophysics Data System (ADS)

Blom, Paul; van Mol, Ton

2011-11-01

Light-emitting diodes are more efficient than conventional lighting, but high production costs limit their uptake. Organic versions that can be produced using a cheap newspaper-style "roll-to-roll" printing process are likely to revolutionize our lighting and signage.

Exciton Hybridisation in Organic-Inorganic Semiconductor Microcavities

DTIC Science & Technology

2002-02-01

hybridizing organic and inorganic semiconductors in microcavities to produce a highly efficient light source that could be either a laser or a very efficient...such process may also have an important effect on the spectral distribution of photoluminescence from the microcavity and can be considered as a...Absorption (solid dots) and photoluminescence emission (open circles) of a thin film of J-aggregated cyanine dyes in a PVA matrix. Note, the chemical

Combination of molecular, morphological, and interfacial engineering to achieve highly efficient and stable plastic solar cells.

PubMed

Chang, Chih-Yu; Cheng, Yen-Ju; Hung, Shih-Hsiu; Wu, Jhong-Sian; Kao, Wei-Shun; Lee, Chia-Hao; Hsu, Chain-Shu

2012-01-24

A flexible solar device showing exceptional air and mechanical stability is produced by simultaneously optimizing molecular structure, active layer morphology, and interface characteristics. The PFDCTBT-C8-based devices with inverted architecture exhibited excellent power conversion efficiencies of 7.0% and 6.0% on glass and flexible substrates, respectively. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Broadband high-efficiency dielectric metasurfaces for the visible spectrum

PubMed Central

Devlin, Robert C.; Khorasaninejad, Mohammadreza; Chen, Wei Ting; Oh, Jaewon; Capasso, Federico

2016-01-01

Metasurfaces are planar optical elements that hold promise for overcoming the limitations of refractive and conventional diffractive optics. Original dielectric metasurfaces are limited to transparency windows at infrared wavelengths because of significant optical absorption and loss at visible wavelengths. Thus, it is critical that new materials and nanofabrication techniques be developed to extend dielectric metasurfaces across the visible spectrum and to enable applications such as high numerical aperture lenses, color holograms, and wearable optics. Here, we demonstrate high performance dielectric metasurfaces in the form of holograms for red, green, and blue wavelengths with record absolute efficiency (>78%). We use atomic layer deposition of amorphous titanium dioxide with surface roughness less than 1 nm and negligible optical loss. We use a process for fabricating dielectric metasurfaces that allows us to produce anisotropic, subwavelength-spaced dielectric nanostructures with shape birefringence. This process is capable of realizing any high-efficiency metasurface optical element, e.g., metalenses and axicons. PMID:27601634

Ultrasmooth Perovskite Film via Mixed Anti-Solvent Strategy with Improved Efficiency.

PubMed

Yu, Yu; Yang, Songwang; Lei, Lei; Cao, Qipeng; Shao, Jun; Zhang, Sheng; Liu, Yan

2017-02-01

Most antisolvents employed in previous research were miscible with perovskite precursor solution. They always led to fast formation of perovskite even if the intermediate stage existed, which was not beneficial to obtain high quality perovskite films and made the formation process less controllable. In this work, a novel ethyl ether/n-hexane mixed antisolvent (MAS) was used to achieve high nucleation density and slow down the formation process of perovskite, producing films with improved orientation of grains and ultrasmooth surfaces. These high quality films exhibited efficient charge transport at the interface of perovskite/hole transport material and perovskite solar cells based on these films showed greatly improved performance with the best power conversion efficiency of 17.08%. This work also proposed a selection principle of MAS and showed that solvent engineering by designing the mixed antisolvent system can lead to the fabrication of high-performance perovskite solar cells.

Planar concentrators at the étendue limit

NASA Astrophysics Data System (ADS)

Winston, Roland; Gordon, Jeffrey M.

2005-08-01

Recently proposed aplanatic imaging designs are integrally combined with nonimaging flux boosters to produce an ultra-compact planar dielectric-filled concentrator that performs near the étendue limit. Such optical devices are attractive for high-efficiency multi-junction photovoltaics at high flux, with realistic power generation of 1 W from a 1 mm2 cell.

PBFA II, a 100 TW Pulsed Power Driver for the Inertial Confinement Fusion Program

DTIC Science & Technology

1985-06-01

providing a 30 MV, 15 ns output pulse,which accelerates lithium ions. The ions will focus onto a pellet containing deuterium-tritium, producing fusion ... energy . Several research areas will be reviewed: low jitter, highly reliable 370 kJ Marx generators; highly synchronized gas switching at 5 MV; efficient

Chapter 5: Residential Furnaces and Boilers Evaluation Protocol. The Uniform Methods Project: Methods for Determining Energy Efficiency Savings for Specific Measures

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

Kurnik, Charles W.; Jacobson, David

The high-efficiency boiler and furnace measure produces gas heating savings resulting from installation of more energy-efficient heating equipment in a residence. Such equipment, which ranges in size from 60 kBtu/hr to 300 kBtu/hr, is installed primarily in single-family homes and multifamily buildings with individual heating systems for each dwelling unit. This protocol does not cover integrated heating and water heating units which can be used in lieu of space heating only equipment.

Highly Efficient Agrobacterium-Mediated Transformation of Wheat Via In Planta Inoculation

NASA Astrophysics Data System (ADS)

Risacher, Thierry; Craze, Melanie; Bowden, Sarah; Paul, Wyatt; Barsby, Tina

This chapter details a reproducible method for the transformation of spring wheat using Agrobacterium tumefaciens via the direct inoculation of bacteria into immature seeds in planta as described in patent WO 00/63398(1. Transformation efficiencies from 1 to 30% have been obtained and average efficiencies of at least 5% are routinely achieved. Regenerated plants are phenotypically normal with 30-50% of transformation events carrying introduced genes at single insertion sites, a higher rate than is typically reported for transgenic plants produced using biolistic transformation methods.

Development of a 200 W CW high efficiency traveling wave tube at 12 GHz. [for use in communication technology satellites

NASA Technical Reports Server (NTRS)

Christensen, J. A.; Tammaru, I.

1974-01-01

The design, development, and test results are reported for an experimental PPM focused, traveling-wave tube that produces 235 watts of CW RF power over 85 MHz centered at 12.080 GHz. The tube uses a coupled cavity RF circuit with a velocity taper for greater than 30 percent basic efficiency. Overall efficiency of 51 percent is achieved by means of a nine stage depressed collector designed at NASA Lewis Research Center. This collector is cooled by direct radiation to deep space.

Efficient, Long Term Production of Monocyte-Derived Macrophages from Human Pluripotent Stem Cells under Partly-Defined and Fully-Defined Conditions

PubMed Central

van Wilgenburg, Bonnie; Browne, Cathy; Vowles, Jane; Cowley, Sally A.

2013-01-01

Human macrophages are specialised hosts for HIV-1, dengue virus, Leishmania and Mycobacterium tuberculosis. Yet macrophage research is hampered by lack of appropriate cell models for modelling infection by these human pathogens, because available myeloid cell lines are, by definition, not terminally differentiated like tissue macrophages. We describe here a method for deriving monocytes and macrophages from human Pluripotent Stem Cells which improves on previously published protocols in that it uses entirely defined, feeder- and serum-free culture conditions and produces very consistent, pure, high yields across both human Embryonic Stem Cell (hESC) and multiple human induced Pluripotent Stem Cell (hiPSC) lines over time periods of up to one year. Cumulatively, up to ∼3×107 monocytes can be harvested per 6-well plate. The monocytes produced are most closely similar to the major blood monocyte (CD14+, CD16low, CD163+). Differentiation with M-CSF produces macrophages that are highly phagocytic, HIV-1-infectable, and upon activation produce a pro-inflammatory cytokine profile similar to blood monocyte-derived macrophages. Macrophages are notoriously hard to genetically manipulate, as they recognise foreign nucleic acids; the lentivector system described here overcomes this, as pluripotent stem cells can be relatively simply genetically manipulated for efficient transgene expression in the differentiated cells, surmounting issues of transgene silencing. Overall, the method we describe here is an efficient, effective, scalable system for the reproducible production and genetic modification of human macrophages, facilitating the interrogation of human macrophage biology. PMID:23951090

Guidance for Efficient Small Animal Imaging Quality Control.

PubMed

Osborne, Dustin R; Kuntner, Claudia; Berr, Stuart; Stout, David

2017-08-01

Routine quality control is a critical aspect of properly maintaining high-performance small animal imaging instrumentation. A robust quality control program helps produce more reliable data both for academic purposes and as proof of system performance for contract imaging work. For preclinical imaging laboratories, the combination of costs and available resources often limits their ability to produce efficient and effective quality control programs. This work presents a series of simplified quality control procedures that are accessible to a wide range of preclinical imaging laboratories. Our intent is to provide minimum guidelines for routine quality control that can assist preclinical imaging specialists in setting up an appropriate quality control program for their facility.

Genomic, proteomic and biochemical analysis of the chitinolytic machinery of Serratia marcescens BJL200.

PubMed

Tuveng, Tina R; Hagen, Live Heldal; Mekasha, Sophanit; Frank, Jeremy; Arntzen, Magnus Øverlie; Vaaje-Kolstad, Gustav; Eijsink, Vincent G H

2017-04-01

The chitinolytic machinery of Serratia marcescens BJL200 has been studied in detail over the last couple of decades, however, the proteome secreted by this Gram-negative bacterium during growth on chitin has not been studied in depth. In addition, the genome of this most studied chitinolytic Serratia strain has until now, not been sequenced. We report a draft genome sequence for S. marcescens BJL200. Using label-free quantification (LFQ) proteomics and a recently developed plate-method for assessing secretomes during growth on solid substrates, we find that, as expected, the chitin-active enzymes (ChiA, B, C, and CBP21) are produced in high amounts when the bacterium grows on chitin. Other proteins produced in high amounts after bacterial growth on chitin provide interesting targets for further exploration of the proteins involved in degradation of chitin-rich biomasses. The genome encodes a fourth chitinase (ChiD), which is produced in low amounts during growth on chitin. Studies of chitin degradation with mixtures of recombinantly produced chitin-degrading enzymes showed that ChiD does not contribute to the overall efficiency of the process. ChiD is capable of converting N,N'-diacetyl chitobiose to N-acetyl glucosamine, but is less efficient than another enzyme produced for this purpose, the Chitobiase. Thus, the role of ChiD in chitin degradation, if any, remains unclear. Copyright © 2017 Elsevier B.V. All rights reserved.

The type of carbohydrates specifically selects microbial community structures and fermentation patterns.

PubMed

Chatellard, Lucile; Trably, Eric; Carrère, Hélène

2016-12-01

The impact on dark fermentation of seven carbohydrates as model substrates of lignocellulosic fractions (glucose, cellobiose, microcrystalline cellulose, arabinose, xylose, xylan and wheat straw) was investigated. Metabolic patterns and bacterial communities were characterized at the end of batch tests inoculated with manure digestate. It was found that hydrogen production was linked to the sugar type (pentose or hexose) and the degree of polymerisation. Hexoses produced less hydrogen, with a specific selection of lactate-producing bacterial community structures. Maximal hydrogen production was five times higher on pentose-based substrates, with specific bacterial community structures producing acetate and butyrate as main metabolites. Low hydrogen amounts accumulated from complex sugars (cellulose, xylan and wheat straw). A relatively high proportion of the reads was affiliated to Ruminococcaceae suggesting an efficient hydrolytic activity. Knowing that the bacterial community structure is very specific to a particular substrate offers new possibilities to design more efficient H 2 -producing biological systems. Copyright © 2016 Elsevier Ltd. All rights reserved.

Analysis of higher order harmonics with holographic reflection gratings

NASA Astrophysics Data System (ADS)

Mas-Abellan, P.; Madrigal, R.; Fimia, A.

2017-05-01

Silver halide emulsions have been considered one of the most energetic sensitive materials for holographic applications. Nonlinear recording effects on holographic reflection gratings recorded on silver halide emulsions have been studied by different authors obtaining excellent experimental results. In this communication specifically we focused our investigation on the effects of refractive index modulation, trying to get high levels of overmodulation that will produce high order harmonics. We studied the influence of the overmodulation and its effects on the transmission spectra for a wide exposure range by use of 9 μm thickness films of ultrafine grain emulsion BB640, exposed to single collimated beams using a red He-Ne laser (wavelength 632.8 nm) with Denisyuk configuration obtaining a spatial frequency of 4990 l/mm recorded on the emulsion. The experimental results show that high overmodulation levels of refractive index produce second order harmonics with high diffraction efficiency (higher than 75%) and a narrow grating bandwidth (12.5 nm). Results also show that overmodulation produce diffraction spectra deformation of the second order harmonic, transforming the spectrum from sinusoidal to approximation of square shape due to very high overmodulation. Increasing the levels of overmodulation of refractive index, we have obtained higher order harmonics, obtaining third order harmonic with diffraction efficiency (up to 23%) and narrowing grating bandwidth (5 nm). This study is the first step to develop a new easy technique to obtain narrow spectral filters based on the use of high index modulation reflection gratings.

Synthesis, Transport, and Thermoelectric Studies of Topological Dirac Semimetal Cd3As2 for Room Temperature Waste Heat Recovery and Energy Conversion

NASA Astrophysics Data System (ADS)

Hosseini, Tahereh A.

Rising rates of the energy consumption and growing concerns over the climate change worldwide have made energy efficiency an urgent problem to address. Nowadays, almost two-thirds of the energy produced by burning fossil fuels to generate electrical power is lost in the form of the heat. On this front, increasing electrical power generation through a waste heat recovery remains one of the highly promising venues of the energy research. Thermo-electric generators (TEGs) directly convert thermal energy into electrical and are the prime candidates for application in low-grade thermal energy/ waste heat recovery. The key commercial TE materials, e.g. PbTe and Bi2Te 3, have room temperature ZT of less than 1, whereas ZT exceeding 3 is required for a TEG to be economically viable. With the thermoelectric efficiency typically within a few percent range and a low efficiency-to-cost ratio of TEGs, there has been a resurgence in the search for new class of thermo-electric materials for developing high efficiency thermo-to-electric energy conversion systems, with phonon-glass electron-crystal materials holding the most promise. Herein, we focus on synthesis, characterization and investigation of electrical, thermo-electrical and thermal characteristics of crystalline Cd 3As2, a high performance 3D topological Dirac semimetal with Dirac fermions dispersing linearly in k3-space and possessing one of the largest electron mobilities known for crystalline materials, i.e. 104-105cm2V-1 s-1. Suppression of carrier backscattering, ultra-high charge carrier mobility, and inherently low thermal conductivity make this semimetal a key candidate for demonstrating high, device-favorable S and in turn ZT. In this work, a low-temperature vapor-based crystallization pathway was developed and optimized to produce free standing 2D cm-size crystals in Cd 3As2. Compared to the bulk crystals produced in previous studies, e.g. Piper-Polich, Bridgman, or flux method, Cd3As 2 samples were synthesized over a considerably shorter time ( only a few hours), were single crystals and highly stochiometric. A high thermopower of up to 613 microV K-1 and the electrical conductivity of 105 S/m were registered within the temperature range of 300-400 K. A 1o-method based on the transfer function was applied to probe a thermal conductivity, k of Cd3As2 platelets. The results yield k of 2.4 W/m.K in the confirmation that the thermal conductivity of Cd3As2 crystals is to approach the amorphous limit at the room temperature. With its peak thermopower attained at the low temperature range of 300-400 K, high electrical conductivity and amorphous limit thermal conductivity, crystalline Cd3As2 grown via a low-T vapor based method demonstrates ZT > 3; the results confirm that as-produced Cd 3As2 platelets hold a high promise and is another phonon-glass electron-crystal TE material for the development of next generation, high efficiency thermo-electric generators and refrigerators operating under normal conditions.

Distinct enhancement of sub-bandgap photoresponse through intermediate band in high dose implanted ZnTe:O alloys

NASA Astrophysics Data System (ADS)

Li, Jing; Ye, Jiandong; Ren, Fangfang; Tang, Dongming; Yang, Yi; Tang, Kun; Gu, Shulin; Zhang, Rong; Zheng, Youdou

2017-03-01

The demand for high efficiency intermediate band (IB) solar cells is driving efforts in producing high quality IB photovoltaic materials. Here, we demonstrate ZnTe:O highly mismatched alloys synthesized by high dose ion implantation and pulsed laser melting exhibiting optically active IB states and efficient sub-gap photoresponse, as well as investigate the effect of pulsed laser melting on the structural and optical recovery in detail. The structural evolution and vibrational dynamics indicates a significant structural recovery of ZnTe:O alloys by liquid phase epitaxy during pulsed laser melting process, but laser irradiation also aggravates the segregation of Te in ZnTe:O alloys. A distinct intermediate band located at 1.8 eV above valence band is optically activated as evidenced by photoluminescence, absorption and photoresponse characteristics. The carrier dynamics indicates that carriers in the IB electronic states have a relatively long lifetime, which is beneficial for the fast separation of carriers excited by photons with sub-gap energy and thus the improved overall conversion efficiency. The reproducible capability of implantation and laser annealing at selective area enable the realization of high efficient lateral junction solar cells, which can ensure extreme light trapping and efficient charge separation.

Novel Low Cost Organic Vapor Jet Printing of Striped High Efficiency Phosphorescent OLEDs for White Lighting

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

Mike Hack

In this program, Universal Display Corporation and University of Michigan proposed to integrate three innovative concepts to meet the DOE's Solid State Lighting (SSL) goals: (1) high-efficiency phosphorescent organic light emitting device (PHOLED{trademark}) technology, (2) a white lighting design that is based on a series of red, green and blue OLED stripes, and (3) the use of a novel cost-effective, high rate, mask-less deposition process called organic vapor jet printing (OVJP). Our PHOLED technology offers up to four-times higher power efficiency than other OLED approaches for general lighting. We believe that one of the most promising approaches to maximizing themore » efficiency of OLED lighting sources is to produce stripes of the three primary colors at such a pitch (200-500 {mu}m) that they appear as a uniform white light to an observer greater than 1 meter (m) away from the illumination source. Earlier work from a SBIR Phase 1 entitled 'White Illumination Sources Using Striped Phosphorescent OLEDs' suggests that stripe widths of less than 500 {mu}m appear uniform from a distance of 1m without the need for an external diffuser. In this program, we intend to combine continued advances in this PHOLED technology with the striped RGB lighting design to demonstrate a high-efficiency, white lighting source. Using this background technology, the team has focused on developing and demonstrating the novel cost-effective OVJP process to fabricate these high-efficiency white PHOLED light sources. Because this groundbreaking OVJP process is a direct printing approach that enables the OLED stripes to be printed without a shadow mask, OVJP offers very high material utilization and high throughput without the costs and wastage associated with a shadow mask (i.e. the waste of material that deposits on the shadow mask itself). As a direct printing technique, OVJP also has the potential to offer ultra-high deposition rates (> 1,000 Angstroms/second) for any size or shaped features. As a result, we believe that this work will lead to the development of a cost-effective manufacturing solution to produce very-high efficiency OLEDs. By comparison to more common ink-jet printing (IJP), OVJP can also produce well-defined patterns without the need to pattern the substrate with ink wells or to dry/anneal the ink. In addition, the material set is not limited by viscosity and solvent solubility. During the program we successfully demonstrated a 6-inch x 6-inch PHOLED lighting panel consisting of fine-featured red, green and blue (R-G-B) stripes (1mm width) using an OVJP deposition system that was designed, procured and installed into UDC's cleanroom as part of this program. This project will significantly accelerate the DOE's ability to meet its 2015 DOE SSL targets of 70-150 lumens/Watt and less than $10 per 1,000 lumens for high CRI lighting index (76-90). Coupled with a low cost manufacturing path through OVJP, we expect that this achievement will enable the DOE to achieve its 2015 performance goals by the year 2013, two years ahead of schedule. As shown by the technical work performed under this program, we believe that OVJP is a very promising technology to produce low cost, high efficacy, color tunable light sources. While we have made significant progress to develop OVJP technology and build a pilot line tool to study basic aspects of the technology and demonstrate a lighting panel prototype, further work needs to be performed before its full potential and commercial viability can be fully assessed.« less

Ku-band high efficiency GaAs MMIC power amplifiers

NASA Technical Reports Server (NTRS)

Tserng, H. Q.; Witkowski, L. C.; Wurtele, M.; Saunier, Paul

1988-01-01

The development of Ku-band high efficiency GaAs MMIC power amplifiers is examined. Three amplifier modules operating over the 13 to 15 GHz frequency range are to be developed. The first MMIC is a 1 W variable power amplifier (VPA) with 35 percent efficiency. On-chip digital gain control is to be provided. The second MMIC is a medium power amplifier (MPA) with an output power goal of 1 W and 40 percent power-added efficiency. The third MMIC is a high power amplifier (HPA) with 4 W output power goal and 40 percent power-added efficiency. An output power of 0.36 W/mm with 49 percent efficiency was obtained on an ion implanted single gate MESFET at 15 GHz. On a dual gate MESFET, an output power of 0.42 W/mm with 27 percent efficiency was obtained. A mask set was designed that includes single stage, two stage, and three stage single gate amplifiers. A single stage 600 micron amplifier produced 0.4 W/mm output power with 40 percent efficiency at 14 GHz. A four stage dual gate amplifier generated 500 mW of output power with 20 dB gain at 17 GHz. A four-bit digital-to-analog converter was designed and fabricated which has an output swing of -3 V to +/- 1 V.

Efficient high-harmonic generation from a stable and compact ultrafast Yb-fiber laser producing 100 μJ, 350 fs pulses based on bendable photonic crystal fiber

NASA Astrophysics Data System (ADS)

Feehan, James S.; Price, Jonathan H. V.; Butcher, Thomas J.; Brocklesby, William S.; Frey, Jeremy G.; Richardson, David J.

2017-01-01

The development of an Yb3+-fiber-based chirped-pulse amplification system and the performance in the generation of extreme ultraviolet (EUV) radiation by high-harmonic generation is reported. The fiber laser produced 100 μJ, 350 fs output pulses with diffraction-limited beam quality at a repetition rate of 16.7 kHz. The system used commercial single-mode, polarization maintaining fiber technology. This included a 40 μm core, easily packaged, bendable final amplifier fiber in order to enable a compact system, to reduce cost, and provide reliable and environmentally stable long-term performance. The system enabled the generation of 0.4 μW of EUV at wavelengths between 27 and 80 nm with a peak at 45 nm using xenon gas. The EUV flux of 1011 photons per second for a driving field power of 1.67 W represents state-of-the-art generation efficiency for single-fiber amplifier CPA systems, corresponding to a maximum calculated energy conversion efficiency of 2.4 × 10-7 from the infrared to the EUV. The potential for high average power operation at increased repetition rates and further suggested technical improvements are discussed. Future applications could include coherent diffractive imaging in the EUV, and high-harmonic spectroscopy.

Intermediate photovoltaic system application experiment operational performance report: Volume 5, for Beverly High School, Beverly, Mass.

NASA Astrophysics Data System (ADS)

1982-02-01

Performance data for the month of January, 1982 for a grid connected photovoltaic power supply in Massachusetts are presented. Data include: monthly and daily electrical energy produced; monthly and daily solar energy incident on the array; monthly and daily array efficiency; plots of energy produced as a function of power level, voltage, cell temperature and time of day; power conditioner input, output and efficiency for each of two individual units and for the total power conditioning system; photovoltaic system efficiency; capacity factor; PV system to load and grid to load energies and corresponding dollar values; daily energy supplies to the load by the PV system; daily PV system availability; monthly and hourly insolation; monthly and hourly temperature average; monthly and hourly wind speed; wind direction distribution; average heating and cooling degree days; number of freeze/thaw cycles; and the data acquisition mode and recording interval plot.

Investigation of the biofuel flue and producer gases cleaning efficiency using ESP

NASA Astrophysics Data System (ADS)

Poškas, Robertas; Sirvydas, Arūnas; Poškas, Povilas; Striūgas, Nerijus; Pedišius, Nerijus; Valinčius, Vitas

2017-11-01

The use of biofuel has been increasing in Europe over the last years, and the reason for that is acceptable cost and the least negative impact on the environment. However, NOx and emissions of fine particulates are important, and biofuel is still a disadvantage compared to oil and natural gas fired systems. Usually, flue gas is filtered in multicyclones or fibre filters before discharge into the atmosphere. Yet, in the case of fine particulates, the filters of such type do not show high effectiveness, thus electrostatic precipitators are used. In this comparative study on biofuel (wood pellets), the collection efficiency of solid particles from a class 3 boiler (50 kW) and from a gasification unit (100 kW) was investigated. Although releases of solid particles from modern boilers are low, a combination of such a boiler with an electrostatic precipitator may reduce the releases of particles to the minimum, and the collection efficiency of the electrostatic precipitator obtained during the investigation was 98-99%. There is a big difference in particle concentrations comparing the systems with flue gas and producer gas. As the working conditions in the test section with producer gas were harder, it led to lower efficiency of the electrostatic precipitator ( 75%).

Influence of methane emissions and vehicle efficiency on the climate implications of heavy-duty natural gas trucks.

PubMed

Camuzeaux, Jonathan R; Alvarez, Ramón A; Brooks, Susanne A; Browne, Joshua B; Sterner, Thomas

2015-06-02

While natural gas produces lower carbon dioxide emissions than diesel during combustion, if enough methane is emitted across the fuel cycle, then switching a heavy-duty truck fleet from diesel to natural gas can produce net climate damages (more radiative forcing) for decades. Using the Technology Warming Potential methodology, we assess the climate implications of a diesel to natural gas switch in heavy-duty trucks. We consider spark ignition (SI) and high-pressure direct injection (HPDI) natural gas engines and compressed and liquefied natural gas. Given uncertainty surrounding several key assumptions and the potential for technology to evolve, results are evaluated for a range of inputs for well-to-pump natural gas loss rates, vehicle efficiency, and pump-to-wheels (in-use) methane emissions. Using reference case assumptions reflecting currently available data, we find that converting heavy-duty truck fleets leads to damages to the climate for several decades: around 70-90 years for the SI cases, and 50 years for the more efficient HPDI. Our range of results indicates that these fuel switches have the potential to produce climate benefits on all time frames, but combinations of significant well-to-wheels methane emissions reductions and natural gas vehicle efficiency improvements would be required.

Highly efficient and selective pressure-assisted photon-induced polymerization of styrene

NASA Astrophysics Data System (ADS)

Guan, Jiwen; Song, Yang

2016-06-01

The polymerization process of condensed styrene to produce polystyrene as an industrially important polymeric material was investigated using a novel approach by combining external compression with ultraviolet radiation. The reaction evolution was monitored as a function of time and the reaction products were characterized by in situ Fourier transform infrared spectroscopy. By optimizing the loading pressures, we observed highly efficient and selective production of polystyrene of different tacticities. Specifically, at relatively low loading pressures, infrared spectra suggest that styrene monomers transform to amorphous atactic polystyrene (APS) with minor crystalline isotactic polystyrene. In contrast, APS was found to be the sole product when polymerization occurs at relatively higher loading pressures. The time-dependent reaction profiles allow the examination of the polymerization kinetics by analyzing the rate constant and activation volume as a function of pressure. As a result, an optimized pressure condition, which allows a barrierless reaction to proceed, was identified and attributed to the very desirable reaction yield and kinetics. Finally, the photoinitiated reaction mechanism and the growth geometry of the polymer chains were investigated from the energy diagram of styrene and by the topology analysis of the crystal styrene. This study shows strong promise to produce functional polymeric materials in a highly efficient and controlled manner.

Graphene-Based Standalone Solar Energy Converter for Water Desalination and Purification.

PubMed

Yang, Yang; Zhao, Ruiqi; Zhang, Tengfei; Zhao, Kai; Xiao, Peishuang; Ma, Yanfeng; Ajayan, Pulickel M; Shi, Gaoquan; Chen, Yongsheng

2018-01-23

Harvesting solar energy for desalination and sewage treatment has been considered as a promising solution to produce clean water. However, state-of-the-art technologies often require optical concentrators and complicated systems with multiple components, leading to poor efficiency and high cost. Here, we demonstrate an extremely simple and standalone solar energy converter consisting of only an as-prepared 3D cross-linked honeycomb graphene foam material without any other supporting components. This simple all-in-one material can act as an ideal solar thermal converter capable of capturing and converting sunlight into heat, which in turn can distill water from various water sources into steam and produce purified water under ambient conditions and low solar flux with very high efficiency. High specific water production rate of 2.6 kg h -1 m -2 g -1 was achieved with near ∼87% under 1 sun intensity and >80% efficiency even under ambient sunlight (<1 sun). This scalable sheet-like material was used to obtain pure drinkable water from both seawater and sewage water under ambient conditions. Our results demonstrate a competent monolithic material platform providing a paradigm change in water purification by using a simple, point of use, reusable, and low-cost solar thermal water purification system for a variety of environmental conditions.

Myostatin gene mutated mice induced with tale nucleases.

PubMed

Zhou, Fangfang; Sun, Ruilin; Chen, Hongyan; Fei, Jian; Lu, Daru

2015-01-01

Myostain gene (MSTN) is expressed primarily in skeletal muscle, and negatively regulates skeletal muscle mass; it has been suggested that mice with MSTN inhibition have reduced adiposity and improved insulin sensitivity. Therefore, it is important to establish a fast and effective gene editing method. In this report, we established the myostatin mutated-mouse model by microinjection of Transcription Activator-Like Effector Nucleases (TALENs) mRNA within the mouse fertilized oocytes and achieved high rates of mutagenesis of the mouse MSTN in C57BL/6J. Six of 45 born mice carried target mutations and we appointed one as the parental mating with wild mouse to produce the F1 and backcross to produce the F2 generation. All the mutations of the mice were examined quickly and efficiently by high-resolution melting curve analysis (HRMA) and then verified by direct sequencing. We obtained the homozygous of the F2 generation which transmitted the mutant alleles to the progeny with 100% efficiency. Mutant mice exhibited increases in muscle mass comparable to those observed in wild-type mice. Therefore, combining TALEN-mediated gene targeting with HRMA technology is a superior method of constructing genetically modified mice through microinjection in the mouse fertilized oocytes with high efficiency and short time of selection.

Experimental Investigation on Effect of Fin Shape on the Thermal-Hydraulic Performance of Compact Fin-and-Tube Heat Exchangers

NASA Astrophysics Data System (ADS)

Moorthy, P.; Oumer, A. N.; Ishak, M.

2018-03-01

The aim of this paper is to investigate the effect of fin shapes on the performance of compact finned flat tube heat exchangers. Three types of fin shapes namely plain, wavy, and rectangular grooved fins attached to three by three arrays of flat tube banks were considered. Moreover, the tubes were deployed in in-line and staggered arrangements. In addition to the fin shapes, the air velocity and the tube inclination angles were varied and the thermal-hydraulic performance was analysed. On the other hand, the temperatures at the tube surfaces were kept constant to produce constant heat flux throughout the study. The results showed that as flowrate increases, the heat transfer increases, however, the friction factor decreases. Staggered arrangement produces higher heat transfer and friction factor than inline fin. Moreover, the rectangular fin is the best in terms of high heat transfer however the drawback of high friction factor leads the fin to have the least efficiency of all. On the other hand, plain fin had the least heat transfer performance however the highest efficiency was achieved. Therefore, plain fin should be used when efficiency is prioritized and rectangular fin when high heat transfer is desired.

The infrared imaging spectrograph (IRIS) for TMT: volume phase holographic grating performance testing and discussion

NASA Astrophysics Data System (ADS)

Chen, Shaojie; Meyer, Elliot; Wright, Shelley A.; Moore, Anna M.; Larkin, James E.; Maire, Jerome; Mieda, Etsuko; Simard, Luc

2014-07-01

Maximizing the grating efficiency is a key goal for the first light instrument IRIS (Infrared Imaging Spectrograph) currently being designed to sample the diffraction limit of the TMT (Thirty Meter Telescope). Volume Phase Holographic (VPH) gratings have been shown to offer extremely high efficiencies that approach 100% for high line frequencies (i.e., 600 to 6000l/mm), which has been applicable for astronomical optical spectrographs. However, VPH gratings have been less exploited in the near-infrared, particularly for gratings that have lower line frequencies. Given their potential to offer high throughputs and low scattered light, VPH gratings are being explored for IRIS as a potential dispersing element in the spectrograph. Our team has procured near-infrared gratings from two separate vendors. We have two gratings with the specifications needed for IRIS current design: 1.51-1.82μm (H-band) to produce a spectral resolution of 4000 and 1.19-1.37μm (J-band) to produce a spectral resolution of 8000. The center wavelengths for each grating are 1.629μm and 1.27μm, and the groove densities are 177l/mm and 440l/mm for H-band R=4000 and J-band R=8000, respectively. We directly measure the efficiencies in the lab and find that the peak efficiencies of these two types of gratings are quite good with a peak efficiency of ~88% at the Bragg angle in both TM and TE modes at H-band, and 90.23% in TM mode, 79.91% in TE mode at J-band for the best vendor. We determine the drop in efficiency off the Bragg angle, with a 20-23% decrease in efficiency at H-band when 2.5° deviation from the Bragg angle, and 25%-28% decrease at J-band when 5° deviation from the Bragg angle.

Energetic and environmental assessment of thermochemical and biochemical ways for producing energy from agricultural solid residues: Coffee Cut-Stems case.

PubMed

García, Carlos A; Peña, Álvaro; Betancourt, Ramiro; Cardona, Carlos A

2018-06-15

Forest residues are an important source of biomass. Among these, Coffee Cut-Stems (CCS) are an abundant wood waste in Colombia obtained from coffee crops renovation. However, only low quantities of these residues are used directly in combustion processes for heating and cooking in coffee farms where their energy efficiency is very low. In the present work, an energy and environmental assessment of two bioenergy production processes (ethanol fermentation and gasification) using CCS as raw material was performed. Biomass gasification seems to be the most promising thermochemical method for bioenergy production whereas, ethanol fermentation is a widely studied biochemical method to produce biofuels. Experimental runs of the CCS gasification were carried out and the synthesis gas composition was monitored. Prior to the fermentation process, a treatment of the CCS is required from which sugar content was determined and then, in the fermentation process, the ethanol yield was calculated. Both processes were simulated in order to obtain the mass and energy balance that are used to assess the energy efficiency and the potential environmental impact (PEI). Moderate high energy efficiency and low environmental impacts were obtained from the CCS gasification. In contrast, high environmental impacts in different categories and low energy efficiencies were calculated from the ethanolic fermentation. Biomass gasification seems to be the most promising technology for the use of Coffee Cut-Stems with high energy yields and low environmental issues. Copyright © 2017 Elsevier Ltd. All rights reserved.

Electrical and Optical Performance Characteristics of 0.74-eV p/n InGaAs Monolithic Interconnected Modules

NASA Technical Reports Server (NTRS)

Wilt, David M.; Fatemi, Navid S.; Jenkins, Phillip P.; Weizer, Victor G.; Hoffman, Richard W., Jr.; Jain, Raj K.; Murray, Christopher S.; Riley, David R.

1997-01-01

There has been a traditional trade-off in thermophotovoltaic (TPV) energy conversion development between system efficiency and power density. This trade-off originates from the use of front surface spectral controls such as selective emitters and various types of filters. A monolithic interconnected module (MIM) structure has been developed which allows for both high power densities and high system efficiencies. The MIM device consists of many individual indium gallium arsenide (InGaAs) cells series-connected on a single semi-insulating indium phosphide (InP) substrate. The MIM is exposed to the entire emitter output, thereby maximizing output power density. An infrared (IR) reflector placed on the rear surface of the substrate returns the unused portion of the emitter output spectrum back to the emitter for recycling, thereby providing for high system efficiencies. Initial MIM development has focused on a 1 sq cm device consisting of eight (8) series interconnected cells. MIM devices, produced from 0.74-eV InGaAs, have demonstrated V(sub oc) = 3.2 volts, J(sub sc) = 70 mA/sq cm, and a fill factor of 66% under flashlamp testing. Infrared (IR) reflectance measurements (greater than 2 micron) of these devices indicate a reflectivity of greater than 82%. MIM devices produced from 0.55-eV InGaAs have also been demonstrated. In addition, conventional p/n InGaAs devices with record efficiencies (11.7% AM0) have been demonstrated.

InGaAs/InP Monolithic Interconnected Modules (MIM) for Thermophotovoltaic Applications

NASA Technical Reports Server (NTRS)

Wilt, David M.; Fatemi, Navid S.; Jenkins, Phillip P.; Weizer, Victor G.; Hoffman, Richard W., Jr.; Scheiman, David A.; Murray, Christopher S.; Riley, David R.

2004-01-01

There has been a traditional trade-off in thermophotovoltaic (TPV) energy conversion development between systems efficiency and power density. This trade-off originates from the use of front surface spectral controls such as selective emitters and various types of filters. A monolithic interconnected module (MIM) structure has been developed which allows for both high power densities and high system efficiencies. The MIM device consists of many individual indium gallium arsenide (InGaAs) devices series -connected on a single semi-insulating indium phosphide (InP) substrate. The MIMs are exposed to the entire emitter output, thereby maximizing output power density. An infrared (IR) reflector placed on the rear surface of the substrate returns the unused portion of the emitter output spectrum back to the emitter for recycling, thereby providing for high system efficiencies. Initial MIM development has focused on a 1 sq cm device consisting of eight series interconnected cells. MIM devices, produced from 0,74 eV InGAAs, have demonstrated V(sub infinity) = 3.23 volts, J(sub sc) = 70 mA/sq cm and a fill factor of 66% under flashlamp testing. Infrared (IR) reflectance measurement (less than 2 microns) of these devices indicate a reflectivity of less than 82%. MIM devices produced from 0.55 eV InGaAs have also been den=monstrated. In addition, conventional p/n InGaAs devices with record efficiencies (11.7% AM1) have been demonstrated.

Structure of deformed silicon and implications for low cost solar cells

NASA Technical Reports Server (NTRS)

Mardesich, N.; Leipold, M. H.; Turner, G. B.; Digges, T. G., Jr.

1978-01-01

The microstructure and minority carrier lifetime of silicon were investigated in uniaxially compressed silicon samples. The objective of the investigation was to determine if it is feasible to produce silicon solar cells from sheet formed by high temperature rolling. The initial structure of the silicon samples ranged from single crystal to fine-grained polycrystals. The samples had been deformed at strain rates of 0.1 to 8.5/sec and temperatures of 1270-1380 C with subsequent annealing at 1270-1380 C. The results suggest that high temperature rolling of silicon to produce sheet for cells of high efficiency is not practical.

Intense ion beam generator

DOEpatents

Humphries, Jr., Stanley; Sudan, Ravindra N.

1977-08-30

Methods and apparatus for producing intense megavolt ion beams are disclosed. In one embodiment, a reflex triode-type pulsed ion accelerator is described which produces ion pulses of more than 5 kiloamperes current with a peak energy of 3 MeV. In other embodiments, the device is constructed so as to focus the beam of ions for high concentration and ease of extraction, and magnetic insulation is provided to increase the efficiency of operation.

Extended cage adjustable speed electric motors and drive packages

DOEpatents

Hsu, John S.

1999-01-01

The rotor cage of a motor is extended, a second stator is coupled to this extended rotor cage, and the windings have the same number of poles. The motor torque and speed can be controlled by either injecting energy into or extracting energy out from the rotor cage. The motor produces less harmonics than existing doubly-fed motors. Consequently, a new type of low cost, high efficiency drive is produced.

Stratified Diffractive Optic Approach for Creating High Efficiency Gratings

NASA Technical Reports Server (NTRS)

Chambers, Diana M.; Nordin, Gregory P.

1998-01-01

Gratings with high efficiency in a single diffracted order can be realized with both volume holographic and diffractive optical elements. However, each method has limitations that restrict the applications in which they can be used. For example, high efficiency volume holographic gratings require an appropriate combination of thickness and permittivity modulation throughout the bulk of the material. Possible combinations of those two characteristics are limited by properties of currently available materials, thus restricting the range of applications for volume holographic gratings. Efficiency of a diffractive optic grating is dependent on its approximation of an ideal analog profile using discrete features. The size of constituent features and, consequently, the number that can be used within a required grating period restricts the applications in which diffractive optic gratings can be used. These limitations imply that there are applications which cannot be addressed by either technology. In this paper we propose to address a number of applications in this category with a new method of creating high efficiency gratings which we call stratified diffractive optic gratings. In this approach diffractive optic techniques are used to create an optical structure that emulates volume grating behavior. To illustrate the stratified diffractive optic grating concept we consider a specific application, a scanner for a space-based coherent wind lidar, with requirements that would be difficult to meet by either volume holographic or diffractive optic methods. The lidar instrument design specifies a transmissive scanner element with the input beam normally incident and the exiting beam deflected at a fixed angle from the optical axis. The element will be rotated about the optical axis to produce a conical scan pattern. The wavelength of the incident beam is 2.06 microns and the required deflection angle is 30 degrees, implying a grating period of approximately 4 microns. Creating a high efficiency volume grating with these parameters would require a grating thickness that cannot be attained with current photosensitive materials. For a diffractive optic grating, the number of binary steps necessary to produce high efficiency combined with the grating period requires feature sizes and alignment tolerances that are also unattainable with current techniques. Rotation of the grating and integration into a space-based lidar system impose the additional requirements that it be insensitive to polarization orientation, that its mass be minimized and that it be able to withstand launch and space environments.

Cultivar development and selection

USDA-ARS?s Scientific Manuscript database

Successful blackberry production and marketing depends on planting cultivars that are adapted to the region, efficiently produce high yields, and have the fruit quality the market, whether local or distant, demands. Blackberry breeding programs have developed cultivars that consumers like to eat and...

Energy efficient engine high pressure turbine ceramic shroud support technology report

NASA Technical Reports Server (NTRS)

Nelson, W. A.; Carlson, R. G.

1982-01-01

This work represents the development and fabrication of ceramic HPT (high pressure turbine) shrouds for the Energy Efficient Engine (E3). Details are presented covering the work performed on the ceramic shroud development task of the NASA/GE Energy Efficient Engine (E3) component development program. The task consists of four phases which led to the selection of a ZrO2-BY2O3 ceramic shroud material system, the development of an automated plasma spray process to produce acceptable shroud structures, the fabrication of select shroud systems for evaluation in laboratory, component, and CF6-50 engine testing, and finally, the successful fabrication of ZrO2-8Y2O3/superpeg, engine quality shrouds for the E3 engine.

Phase plate technology for laser marking of magnetic discs

DOEpatents

Neuman, Bill; Honig, John; Hackel, Lloyd; Dane, C. Brent; Dixit, Shamasundar

1998-01-01

An advanced design for a phase plate enables the distribution of spots in arbitrarily shaped patterns with very high uniformity and with a continuously or near-continuously varying phase pattern. A continuous phase pattern eliminates large phase jumps typically expected in a grating that provides arbitrary shapes. Large phase jumps increase scattered light outside of the desired pattern, reduce efficiency and can make the grating difficult to manufacture. When manufacturing capabilities preclude producing a fully continuous grating, the present design can be easily adapted to minimize manufacturing errors and maintain high efficiencies. This continuous grating is significantly more efficient than previously described Dammann gratings, offers much more flexibility in generating spot patterns and is easier to manufacture and replicate than a multi-level phase grating.

Countercurrent extraction of soluble sugars from almond hulls and assessment of the bioenergy potential.

PubMed

Holtman, Kevin M; Offeman, Richard D; Franqui-Villanueva, Diana; Bayati, Andre K; Orts, William J

2015-03-11

Almond hulls contain considerable proportions (37% by dry weight) of water-soluble, fermentable sugars (sucrose, glucose, and fructose), which can be extracted for industrial purposes. The maximum optimal solids loading was determined to be 20% for sugar extraction, and the addition of 0.5% (w/v) pectinase aided in maintaining a sufficient free water volume for sugar recovery. A laboratory countercurrent extraction experiment utilizing a 1 h steep followed by three extraction (wash) stages produced a high-concentration (131 g/L fermentable sugar) syrup. Overall, sugar recovery efficiency was 88%. The inner stage washing efficiencies were compatible with solution equilibrium calculations, indicating that efficiency was high. The concentrated sugar syrup was fermented to ethanol at high efficiency (86% conversion), and ethanol concentrations in the broth were 7.4% (v/v). Thin stillage contained 233 g SCOD/L, which was converted to biomethane at an efficiency of 90% with a biomethane potential of 297 mL/g SCODdestroyed. Overall, results suggested that a minima of 49 gal (185 L) ethanol and 75 m(3) methane/t hulls (dry whole hull basis) are achievable.

Metallic Junction Thermoelectric Device Simulations

NASA Technical Reports Server (NTRS)

Duzik, Adam J.; Choi, Sang H.

2017-01-01

Thermoelectric junctions made of semiconductors have existed in radioisotope thermoelectric generators (RTG) for deep space missions, but are currently being adapted for terrestrial energy harvesting. Unfortunately, these devices are inefficient, operating at only 7% efficiency. This low efficiency has driven efforts to make high-figure-of-merit thermoelectric devices, which require a high electrical conductivity but a low thermal conductivity, a combination that is difficult to achieve. Lowered thermal conductivity has increased efficiency, but at the cost of power output. An alternative setup is to use metallic junctions rather than semiconductors as thermoelectric devices. Metals have orders of magnitude more electrons and electronic conductivities higher than semiconductors, but thermal conductivity is higher as well. To evaluate the viability of metallic junction thermoelectrics, a two dimensional heat transfer MATLAB simulation was constructed to calculate efficiency and power output. High Seebeck coefficient alloys, Chromel (90%Ni-10%Cr) and Constantan (55%Cu-45%Ni), produced efficiencies of around 20-30%. Parameters such as the number of layers of junctions, lateral junction density, and junction sizes for both series- and parallel-connected junctions were explored.

Highly Flexible Dye-sensitized Solar Cells Produced by Sewing Textile Electrodes on Cloth

PubMed Central

Yun, Min Ju; Cha, Seung I.; Seo, Seon Hee; Lee, Dong Y.

2014-01-01

Textile forms of solar cells possess special advantages over other types of solar cells, including their light weight, high flexibility, and mechanical robustness. Recent demand for wearable devices has promoted interest in the development of high-efficiency textile-based solar cells for energy suppliers. However, the weaving process occurs under high-friction, high-tension conditions that are not conducive to coated solar-cell active layers or electrodes deposited on the wire or strings. Therefore, a new approach is needed for the development of textile-based solar cells suitable for woven fabrics for wide-range application. In this report, we present a highly flexible, efficient DSSC, fabricated by sewing textile-structured electrodes onto casual fabrics such as cotton, silk, and felt, or paper, thereby forming core integrated DSSC structures with high energy-conversion efficiency (~5.8%). The fabricated textile-based DSSC devices showed high flexibility and high performance under 4-mm radius of curvature over thousands of deformation cycles. Considering the vast number of textile types, our textile-based DSSC devices offer a huge range of applications, including transparent, stretchable, wearable devices. PMID:24957920

Highly flexible dye-sensitized solar cells produced by sewing textile electrodes on cloth.

PubMed

Yun, Min Ju; Cha, Seung I; Seo, Seon Hee; Lee, Dong Y

2014-06-24

Textile forms of solar cells possess special advantages over other types of solar cells, including their light weight, high flexibility, and mechanical robustness. Recent demand for wearable devices has promoted interest in the development of high-efficiency textile-based solar cells for energy suppliers. However, the weaving process occurs under high-friction, high-tension conditions that are not conducive to coated solar-cell active layers or electrodes deposited on the wire or strings. Therefore, a new approach is needed for the development of textile-based solar cells suitable for woven fabrics for wide-range application. In this report, we present a highly flexible, efficient DSSC, fabricated by sewing textile-structured electrodes onto casual fabrics such as cotton, silk, and felt, or paper, thereby forming core integrated DSSC structures with high energy-conversion efficiency (~5.8%). The fabricated textile-based DSSC devices showed high flexibility and high performance under 4-mm radius of curvature over thousands of deformation cycles. Considering the vast number of textile types, our textile-based DSSC devices offer a huge range of applications, including transparent, stretchable, wearable devices.

High throughput electrospinning of high-quality nanofibers via an aluminum disk spinneret

NASA Astrophysics Data System (ADS)

Zheng, Guokuo

In this work, a simple and efficient needleless high throughput electrospinning process using an aluminum disk spinneret with 24 holes is described. Electrospun mats produced by this setup consisted of fine fibers (nano-sized) of the highest quality while the productivity (yield) was many times that obtained from conventional single-needle electrospinning. The goal was to produce scaled-up amounts of the same or better quality nanofibers under variable concentration, voltage, and the working distance than those produced with the single needle lab setting. The fiber mats produced were either polymer or ceramic (such as molybdenum trioxide nanofibers). Through experimentation the optimum process conditions were defined to be: 24 kilovolt, a distance to collector of 15cm. More diluted solutions resulted in smaller diameter fibers. Comparing the morphologies of the nanofibers of MoO3 produced by both the traditional and the high throughput set up it was found that they were very similar. Moreover, the nanofibers production rate is nearly 10 times than that of traditional needle electrospinning. Thus, the high throughput process has the potential to become an industrial nanomanufacturing process and the materials processed by it may be used as filtration devices, in tissue engineering, and as sensors.

A Transforming Marker That Produces Merodiploids with High Efficiency and Stable Transformants with Low Efficiency in Streptococcus

PubMed Central

Ravin, Arnold W.; Ma, Michael

1975-01-01

A mutation (ery-r8) conferring a high level of resistance to erythromycin in the Challis strain of Streptoccus sanguis can be transferred to wild-type erythromycin-sensitive recipients via single molecules of donor DNA. The transformants thus produced are of two types: (1) cells slightly more resistant to erythromycin than wild-type and capable of segregating (at a frequency of 2 x 10-4/bacterium/generation) either wild-type or highly-resistant cells like the original donor type; (2) cells phenotypically and genotypically identical to the original donor type. The unstable diploids (ery-r8/+) occur with a frequency equivalent to that obtained with high-efficiency (HE) markers, whereas the stable donor-type (ery-r8) transformants occur with about five hundred times lower frequency. Penetration of the wild-type recipient by more than one molecule of DNA bearing the ery-r8 marker increases by as much as seven times the incidence of stable transformants. UV-irradiation of molecules bearing the ery-r8 marker diminishes their ability to cooperate in producing a stable transformant, although the UV sensitivity of stable transformant production by a single DNA molecule is not different from that of diploid production. Hence, stable transformants do not appear to be produced by a process typical of low efficiency (LE) markers, which are generally highly sensitive to ultraviolet irradiation. Moreover, stable ery-r8 transformants are produced with equally low frequencies in strains of S. pneumoniae that discriminate (hex+) and fail to discriminate (hex -) between HE and LE markers. We postulate that all transformations by the ery-r8 marker result in ery-r8/+ diploids, and that segregation results in the infrequent stable transformants of the original donor type. This hypothesis is supported by the observations that rifampin treatment of ery-r8/+ populations increases the frequency of segregation and similar treatment of wild-type recipients undergoing transformation by the ery-r8 marker increases the frequency of stable transformants.—In producing the ery-r8/+ transformant the r8 allele is integrated close to the site of its wild-type homolog, since single molecules of DNA from this transformant can be shown to carry both alleles. Segregation of either the ery-r8 or + allele is not detectably enhanced by acridine orange or thymidine deprivation.—The ery-r8 marker occurs close to a site of mutation (ery-r2) which confers erythromycin resistance upon ribosomes. When the r2 and r8 markers are jointly transferred, ery-r2-r8/+ genomes are produced in which the r2 marker is stably integrated but the r8 marker is unstably adjoined to its wild-type homolog. Thus, the duplicated region can be quite short. When the ery-r8 marker is stably integrated, the region of the marker is refractory to subsequent transformation. Markers with properties like ery-r8 are not particularly rare, being found with a frequency of about 4% among spontaneous mutations to erythromycin resistance. PMID:1232022

Enhanced energy conversion efficiency from high strength synthetic organic wastewater by sequential dark fermentative hydrogen production and algal lipid accumulation.

PubMed

Ren, Hong-Yu; Liu, Bing-Feng; Kong, Fanying; Zhao, Lei; Xing, Defeng; Ren, Nan-Qi

2014-04-01

A two-stage process of sequential dark fermentative hydrogen production and microalgal cultivation was applied to enhance the energy conversion efficiency from high strength synthetic organic wastewater. Ethanol fermentation bacterium Ethanoligenens harbinense B49 was used as hydrogen producer, and the energy conversion efficiency and chemical oxygen demand (COD) removal efficiency reached 18.6% and 28.3% in dark fermentation. Acetate was the main soluble product in dark fermentative effluent, which was further utilized by microalga Scenedesmus sp. R-16. The final algal biomass concentration reached 1.98gL(-1), and the algal biomass was rich in lipid (40.9%) and low in protein (23.3%) and carbohydrate (11.9%). Compared with single dark fermentation stage, the energy conversion efficiency and COD removal efficiency of two-stage system remarkably increased 101% and 131%, respectively. This research provides a new approach for efficient energy production and wastewater treatment using a two-stage process combining dark fermentation and algal cultivation. Copyright © 2014 Elsevier Ltd. All rights reserved.

LED power efficiency of biomass, fatty acid, and carotenoid production in Nannochloropsis microalgae.

PubMed

Ma, Ruijuan; Thomas-Hall, Skye R; Chua, Elvis T; Eltanahy, Eladl; Netzel, Michael E; Netzel, Gabriele; Lu, Yinghua; Schenk, Peer M

2018-03-01

The microalga Nannochloropsis produces high-value omega-3-rich fatty acids and carotenoids. In this study the effects of light intensity and wavelength on biomass, fatty acid, and carotenoid production with respect to light output efficiency were investigated. Similar biomass and fatty acid yields were obtained at high light intensity (150 μmol m -2  s -1 ) LEDs on day 7 and low light intensity (50 μmol m -2  s -1 ) LEDs on day 11 during cultivation, but the power efficiencies of biomass and fatty acid (specifically eicosapentaenoic acid) production were higher for low light intensity. Interestingly, low light intensity enhanced both, carotenoid power efficiency of carotenoid biosynthesis and yield. White LEDs were neither advantageous for biomass and fatty acid yields, nor the power efficiency of biomass, fatty acid, and carotenoid production. Noticeably, red LED resulted in the highest biomass and fatty acid power efficiency, suggesting that LEDs can be fine-tuned to grow Nannochloropsis algae more energy-efficiently. Copyright © 2017 Elsevier Ltd. All rights reserved.

A Burkholderia sacchari cell factory: production of poly-3-hydroxybutyrate, xylitol and xylonic acid from xylose-rich sugar mixtures.

PubMed

Raposo, Rodrigo S; de Almeida, M Catarina M D; de Oliveira, M da Conceição M A; da Fonseca, M Manuela; Cesário, M Teresa

2017-01-25

Efficient production of poly-3-hydroxybutyrate (P(3HB)) based on glucose-xylose mixtures simulating different types of lignocellulosic hydrolysate (LCH) was addressed using Burkholderia sacchari, a wild strain capable of metabolizing both sugars and producing P(3HB). Carbon catabolite repression was avoided by maintaining glucose concentration below 10g/L. Xylose concentrations above 30g/L were inhibitory for growth and production. In fed-batch cultivations, pulse size and feed addition rate were controlled in order to reach high productivities and efficient sugar consumptions. High xylose uptake and P(3HB) productivity were attained with glucose-rich mixtures (glucose/xylose ratio in the feed=1.5w/w) using high feeding rates, while with xylose-richer feeds (glucose/xylose=0.8w/w), a lower feeding rate is a robust strategy to avoid xylose build-up in the medium. Xylitol production was observed with xylose concentrations in the medium above 30-40g/L. With sugar mixtures featuring even lower glucose/xylose ratios, i.e. xylose-richer feeds (glucose/xylose=0.5), xylonic acid (a second byproduct) was produced. This is the first report of the ability of Burkholderia sacchari to produce both xylitol and xylonic acid. Copyright © 2016 Elsevier B.V. All rights reserved.

Amylolytic bacterial lactic acid fermentation - a review.

PubMed

Reddy, Gopal; Altaf, Md; Naveena, B J; Venkateshwar, M; Kumar, E Vijay

2008-01-01

Lactic acid, an enigmatic chemical has wide applications in food, pharmaceutical, leather, textile industries and as chemical feed stock. Novel applications in synthesis of biodegradable plastics have increased the demand for lactic acid. Microbial fermentations are preferred over chemical synthesis of lactic acid due to various factors. Refined sugars, though costly, are the choice substrates for lactic acid production using Lactobacillus sps. Complex natural starchy raw materials used for production of lactic acid involve pretreatment by gelatinization and liquefaction followed by enzymatic saccharification to glucose and subsequent conversion of glucose to lactic acid by Lactobacillus fermentation. Direct conversion of starchy biomass to lactic acid by bacteria possessing both amylolytic and lactic acid producing character will eliminate the two step process to make it economical. Very few amylolytic lactic acid bacteria with high potential to produce lactic acid at high substrate concentrations are reported till date. In this view, a search has been made for various amylolytic LAB involved in production of lactic acid and utilization of cheaply available renewable agricultural starchy biomass. Lactobacillus amylophilus GV6 is an efficient and widely studied amylolytic lactic acid producing bacteria capable of utilizing inexpensive carbon and nitrogen substrates with high lactic acid production efficiency. This is the first review on amylolytic bacterial lactic acid fermentations till date.

Helium (3) Rich Solar Flares

DOE R&D Accomplishments Database

Colgate, S. A.; Audouze, J.; Fowler, W. A.

1977-05-03

The extreme enrichment of {sup 3} He {sup 4} He greater than or equal to 1 in some solar flares as due to spallation and the subsequent confinement of the products in a high temperature, kT approx. = 200 keV, high density, n{sub e} approx. = 3 x 10{sup 15} cm {sup -3} plasma associated with the magnetic instability producing the flare is interpreted. The pinch or filament is a current of high energy protons that creates the spallation and maintains the temperature that produces the high energy x-ray spectrum and depletes other isotopes D, Li, Be, and B as observed. Finally the high temperature plasma is a uniquely efficient spallation target that is powered by the interaction of stellar convection and self generated magnetic field.

Bioblendstocks that Enable High Efficiency Engine Designs

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

McCormick, Robert L.; Fioroni, Gina M.; Ratcliff, Matthew A.

2016-11-03

The past decade has seen a high level of innovation in production of biofuels from sugar, lipid, and lignocellulose feedstocks. As discussed in several talks at this workshop, ethanol blends in the E25 to E50 range could enable more highly efficient spark-ignited (SI) engines. This is because of their knock resistance properties that include not only high research octane number (RON), but also charge cooling from high heat of vaporization, and high flame speed. Emerging alcohol fuels such as isobutanol or mixed alcohols have desirable properties such as reduced gasoline blend vapor pressure, but also have lower RON than ethanol.more » These fuels may be able to achieve the same knock resistance benefits, but likely will require higher blend levels or higher RON hydrocarbon blendstocks. A group of very high RON (>150) oxygenates such as dimethyl furan, methyl anisole, and related compounds are also produced from biomass. While providing no increase in charge cooling, their very high octane numbers may provide adequate knock resistance for future highly efficient SI engines. Given this range of options for highly knock resistant fuels there appears to be a critical need for a fuel knock resistance metric that includes effects of octane number, heat of vaporization, and potentially flame speed. Emerging diesel fuels include highly branched long-chain alkanes from hydroprocessing of fats and oils, as well as sugar-derived terpenoids. These have relatively high cetane number (CN), which may have some benefits in designing more efficient CI engines. Fast pyrolysis of biomass can produce diesel boiling range streams that are high in aromatic, oxygen and acid contents. Hydroprocessing can be applied to remove oxygen and consequently reduce acidity, however there are strong economic incentives to leave up to 2 wt% oxygen in the product. This oxygen will primarily be present as low CN alkyl phenols and aryl ethers. While these have high heating value, their presence in diesel fuel at significant volume percentage will require higher CN blendstocks or the use of cetane improving additives.« less

Increasing the Efficiency on Producing Radiology Reports for Breast Cancer Diagnosis by Means of Structured Reports. A Comparative Study.

PubMed

Segrelles, J Damian; Medina, Rosana; Blanquer, Ignacio; Martí-Bonmatí, Luis

2017-05-18

Radiology reports are commonly written on free-text using voice recognition devices. Structured reports (SR) have a high potential but they are usually considered more difficult to fill-in so their adoption in clinical practice leads to a lower efficiency. However, some studies have demonstrated that in some cases, producing SRs may require shorter time than plain-text ones. This work focuses on the definition and demonstration of a methodology to evaluate the productivity of software tools for producing radiology reports. A set of SRs for breast cancer diagnosis based on BI-RADS have been developed using this method. An analysis of their efficiency with respect to free-text reports has been performed. The methodology proposed compares the Elapsed Time (ET) on a set of radiological reports. Free-text reports are produced with the speech recognition devices used in the clinical practice. Structured reports are generated using a web application generated with TRENCADIS framework. A team of six radiologists with three different levels of experience in the breast cancer diagnosis was recruited. These radiologists performed the evaluation, each one introducing 50 reports for mammography, 50 for ultrasound scan and 50 for MRI using both approaches. Also, the Relative Efficiency (REF) was computed for each report, dividing the ET of both methods. We applied the T-Student (T-S) test to compare the ETs and the ANOVA test to compare the REFs. Both tests were computed using the SPSS software. The study produced three DICOM-SR templates for Breast Cancer Diagnosis on mammography, ultrasound and MRI, using RADLEX terms based on BIRADs 5th edition. The T-S test on radiologists with high or intermediate profile, showed that the difference between the ET was only statistically significant for mammography and ultrasound. The ANOVA test performed grouping the REF by modalities, indicated that there were no significant differences between mammograms and ultrasound scans, but both have significant statistical differences with MRI. The ANOVA test of the REF for each modality, indicated that there were only significant differences in Mammography (ANOVA p = 0.024) and Ultrasound (ANOVA p = 0.008). The ANOVA test for each radiologist profile, indicated that there were significant differences on the high profile (ANOVA p = 0.028) and medium (ANOVA p = 0.045). In this work, we have defined and demonstrated a methodology to evaluate the productivity of software tools for producing radiology reports in Breast Cancer. We have evaluated that adopting Structured Reporting in mammography and ultrasound studies in breast cancer diagnosis improves the performance in producing reports.

Turbo-Brayton cryocooler technology for low-temperature space applications

NASA Astrophysics Data System (ADS)

Zagarola, Mark V.; Breedlove, Jeffrey F.; McCormick, John A.; Swift, Walter L.

2003-03-01

High performance, low temperature cryocoolers are being developed for future space-borne telescopes and instruments. To meet mission objectives, these coolers must be compact, lightweight, have low input power, operate reliably for 5-10 years, and produce no disturbances that would affect the pointing accuracy of the instruments. This paper describes progress in the development of turbo-Brayton cryocoolers addressing cooling in the 5 K to 20 K temperature range for loads of up to 300 mW. The key components for these cryocoolers are the miniature, high-speed turbomachines and the high performance recuperative heat exchangers. The turbomachines use gas-bearings to support the low mass, high speed rotors, resulting in negligible vibration and long life. Precision fabrication techniques are used to produce the necessary micro-scale geometric features that provide for high cycle efficiencies at these reduced sizes. Turbo-Brayton cryocoolers for higher temperatures and loads have been successfully developed for space applications. For efficient operation at low temperatures and capacities, advances in the core technologies have been pursued. Performance test results of a new, low poer compressor will be presented, and early cryogenic test results on a low temperature expansion turbine will be discussed. Projections for several low temperature cooler configurations are summarized.

Comparison of Planning Quality and Efficiency Between Conventional and Knowledge-based Algorithms in Nasopharyngeal Cancer Patients Using Intensity Modulated Radiation Therapy.

PubMed

Chang, Amy T Y; Hung, Albert W M; Cheung, Fion W K; Lee, Michael C H; Chan, Oscar S H; Philips, Helen; Cheng, Yung-Tang; Ng, Wai-Tong

2016-07-01

Intensity modulated radiation therapy (IMRT) is widely used to achieve a highly conformal dose and improve treatment outcome. However, plan quality and planning time are institute and planner dependent, and no standardized tool exists to recognize an optimal plan. RapidPlan, a knowledge-based algorithm, can generate constraints to assist optimization and produce high-quality IMRT plans. This report evaluated the quality and efficiency of using RapidPlan in nasopharyngeal carcinoma (NPC) IMRT planning. RapidPlan was configured using 79 radical IMRT plans for NPC; 20 consecutive NPC patients indicated for radical radiation therapy between October 2014 and May 2015 were then recruited to assess its performance. The ability of RapidPlan to produce acceptable plans was evaluated. For plans that could not achieve clinical acceptance, manual touch-up was performed. The IMRT plans produced without RapidPlan (manual plans) and with RapidPlan (RP-2 plans, including those with manual touch-up) were compared in terms of dosimetric quality and planning efficiency. RapidPlan by itself could produce clinically acceptable plans for 9 of the 20 patients; manual touch-up increased the number of acceptable plans (RP-2 plans) to 19. The target dose coverage and conformity were very similar. No difference was found in the maximum dose to the brainstem and optic chiasm. RP-2 plans delivered a higher maximum dose to the spinal cord (46.4 Gy vs 43.9 Gy, P=.002) but a lower dose to the parotid (mean dose to right parotid, 37.3 Gy vs 45.4 Gy; left, 34.4 Gy vs 43.1 Gy; P<.001) and the right cochlea (mean dose, 48.6 Gy vs 52.6 Gy; P=.02). The total planning time for RP-2 plans was significantly less than that for manual plans (64 minutes vs 295 minutes, P<.001). This study shows that RapidPlan can significantly improve planning efficiency and produce quality IMRT plans for NPC patients. Copyright © 2016 Elsevier Inc. All rights reserved.

Ultra-High Efficiency, High-Concentration PV System Based On Spectral Division Between GaInP/GaInAs/Ge And BPC Silicon Cells

NASA Astrophysics Data System (ADS)

Benítez, P.; Mohedano, R.; Buljan, M.; Miñano, J. C.; Sun, Y.; Falicoff, W.; Vilaplana, J.; Chaves, J.; Biot, G.; López, J.

2011-12-01

A novel HCPV nonimaging concentrator concept with high concentration (>500×) is presented. It uses the combination of a commercial concentration GaInP/GaInAs/Ge 3J cell and a concentration Back-Point-Contact (BPC) concentration silicon cell for efficient spectral utilization, and external confinement techniques for recovering the 3J cell's reflection. The primary optical element (POE) is a flat Fresnel lens and the secondary optical element (SOE) is a free-form RXI-type concentrator with a band-pass filter embedded it, both POE and SOE performing Köhler integration to produce light homogenization. The band-pass filter sends the IR photons in the 900-1200 nm band to the silicon cell. Computer simulations predict that four-terminal terminal designs could achieve ˜46% added cell efficiencies using commercial 39% 3J and 26% Si cells. A first proof-of concept receiver prototype has been manufactured using a simpler optical architecture (with a lower concentration, ˜100× and lower simulated added efficiency), and experimental measurements have shown up to 39.8% 4J receiver efficiency using a 3J with peak efficiency of 36.9%.

Planar concentrators near the étendue limit.

PubMed

Winston, Roland; Gordon, Jeffrey M

2005-10-01

Recently proposed aplanatic imaging designs are integrally combined with nonimaging flux boosters to produce an ultracompact planar glass-filled concentrator that performs near the étendue limit. Such optical devices are attractive for high-efficiency multijunction photovoltaics at high flux, with realistic power generation of 1 W from a 1 mm2 cell. When deployed in reverse, our designs provide collimation even for high-numerical-aperture light sources.

A modular optically powered floating high voltage generator.

PubMed

Antonini, P; Borsato, E; Carugno, G; Pegoraro, M; Zotto, P

2013-02-01

The feasibility of fully floating high voltage (HV) generation was demonstrated producing a prototype of a modular HV system. The primary power source is provided by a high efficiency semiconductor power cell illuminated by a laser system ensuring the floating nature of each module. The HV is then generated by dc-dc conversion and a HV multiplier. The possibility of series connection among modules was verified.

Planar concentrators near the étendue limit

NASA Astrophysics Data System (ADS)

Winston, Roland; Gordon, Jeffrey M.

2005-10-01

Recently proposed aplanatic imaging designs are integrally combined with nonimaging flux boosters to produce an ultracompact planar glass-filled concentrator that performs near the étendue limit. Such optical devices are attractive for high-efficiency multijunction photovoltaics at high flux, with realistic power generation of 1 W from a 1 mm² cell. When deployed in reverse, our designs provide collimation even for high-numerical-aperture light sources.

Innovative Inverted Magnetron Experiments and Theory

DTIC Science & Technology

2015-06-01

and characterized the Recirculating Planar Magnetron (RPM), a new type of High Power Microwave (HPM) device. Researchers have simulated the operation... power extraction is desired. In simulation, the RPM-CACE was up to 70% efficient, producing peak microwave powers of 420 MW. 15. SUBJECT TERMS High ...type of High Power Microwave (HPM) device. Using HFSS, MAGIC, and ICEPIC, researchers have simulated the operation of the device in both a

Efficient production of a gene mutant cell line through integrating TALENs and high-throughput cell cloning.

PubMed

Sun, Changhong; Fan, Yu; Li, Juan; Wang, Gancheng; Zhang, Hanshuo; Xi, Jianzhong Jeff

2015-02-01

Transcription activator-like effectors (TALEs) are becoming powerful DNA-targeting tools in a variety of mammalian cells and model organisms. However, generating a stable cell line with specific gene mutations in a simple and rapid manner remains a challenging task. Here, we report a new method to efficiently produce monoclonal cells using integrated TALE nuclease technology and a series of high-throughput cell cloning approaches. Following this method, we obtained three mTOR mutant 293T cell lines within 2 months, which included one homozygous mutant line. © 2014 Society for Laboratory Automation and Screening.

Cryopreservation of Human Pluripotent Stem Cells in Defined Medium

PubMed Central

Liu, Weiwei; Chen, Guokai

2014-01-01

This protocol describes a cryopreservation procedure using an enzyme-free dissociation method to harvest cells and preserve cells in albumin-free chemically defined E8 medium for human pluripotent stem cells (hPSCs). The dissociation by EDTA/PBS produces small cell aggregates that allow high survival efficiency in passaging and cryopreservation. The preservation in E8 medium eliminates serum or other animal products, and is suitable for the increasing demand for high quality hPSCs in translational research. In combination with the special feature of EDTA/PBS dissociation, this protocol allows efficient cryopreservation in more time-saving manner. PMID:25366897

Full Scale Technology Demonstration of a Modern Counterrotating Unducted Fan Engine Concept. Design Report

NASA Technical Reports Server (NTRS)

1987-01-01

The Unducted Fan engine (UDF trademark) concept is based on an ungeared, counterrotating, unducted, ultra-high-bypass turbofan configuration. This engine is being developed to provide a high thrust-to-weight ratio power plant with exceptional fuel efficiency for subsonic aircraft application. This report covers the design methodology and details for the major components of this engine. The design intent of the engine is to efficiently produce 25,000 pounds of static thrust while meeting life and stress requirements. The engine is required to operate at Mach numbers of 0.8 or above.

An Inductorless Self-Controlled Rectifier for Piezoelectric Energy Harvesting

PubMed Central

Lu, Shaohua; Boussaid, Farid

2015-01-01

This paper presents a high-efficiency inductorless self-controlled rectifier for piezoelectric energy harvesting. High efficiency is achieved by discharging the piezoelectric device (PD) capacitance each time the current produced by the PD changes polarity. This is achieved automatically without the use of delay lines, thereby making the proposed circuit compatible with any type of PD. In addition, the proposed rectifier alleviates the need for an inductor, making it suitable for on-chip integration. Reported experimental results show that the proposed rectifier can harvest up to 3.9 times more energy than a full wave bridge rectifier. PMID:26610492

An Inductorless Self-Controlled Rectifier for Piezoelectric Energy Harvesting.

PubMed

Lu, Shaohua; Boussaid, Farid

2015-11-19

This paper presents a high-efficiency inductorless self-controlled rectifier for piezoelectric energy harvesting. High efficiency is achieved by discharging the piezoelectric device (PD) capacitance each time the current produced by the PD changes polarity. This is achieved automatically without the use of delay lines, thereby making the proposed circuit compatible with any type of PD. In addition, the proposed rectifier alleviates the need for an inductor, making it suitable for on-chip integration. Reported experimental results show that the proposed rectifier can harvest up to 3.9 times more energy than a full wave bridge rectifier.

Efficient THZ Source Based on Cascaded Optical Down-Conversion in Orientation-Patterned GaAs Structures

DTIC Science & Technology

2008-11-20

techniques for generating THz radiation [5], none of them provides a THz source which is simultaneously ( i ) compact, (ii) highly efficient, (iii...are very attractive for QPM THz-wave generation because of several appealing properties, namely ( i ) small THz absorption coefficient (smaller by an...with periodically- inverted crystalline orientation were used for QPM THz generation: ( i ) diffusion-bonded GaAs (DB-GaAs) [49], produced by

Efficient, deep-blue TADF-emitters for OLED display applications (Conference Presentation)

NASA Astrophysics Data System (ADS)

Volz, Daniel; Baumann, Thomas

2016-09-01

Currently, the mobile display market is strongly shifting towards AMOLED technology, in order to enable curved and flexible displays. This leads to a growing demand for highly efficient OLED emitters to reduce the power consumption and increase display resolution at the same time. While highly efficient green and red OLEDs already found their place in commercial OLED-displays, the lack of efficient blue emitters is still an issue. Consequently, the active area for blue is considerably larger than for green and red pixels, to make up for the lower efficiency. We intend to close this efficiency-gap with novel emitters based on thermally activated delayed fluorescence (TADF) technology. Compared to state-of-the-art fluorescent dopants, the efficiency of TADF-emitters is up to four times higher. At the same time, it is possible to design them in a way to maintain deep blue emission, i.e. CIE y < 0.2. These aspects are relevant to produce efficient high resolution AMOLED displays. Apart from these direct customer benefits, our TADF technology does not contain any rare elements, which allows for the fabrication of sustainable OLED technology. In this work, we highlight one of our recently developed blue TADF materials. Basic material properties as well as first device results are discussed. In a bottom-emitting device, a CIEx/CIEy coordinate of (0.16/0.17) was achieved with efficiency values close to 20% EQE.

'Squeezing' near-field thermal emission for ultra-efficient high-power thermophotovoltaic conversion.

PubMed

Karalis, Aristeidis; Joannopoulos, J D

2016-07-01

We numerically demonstrate near-field planar ThermoPhotoVoltaic systems with very high efficiency and output power, at large vacuum gaps. Example performances include: at 1200 °K emitter temperature, output power density 2 W/cm(2) with ~47% efficiency at 300 nm vacuum gap; at 2100 °K, 24 W/cm(2) with ~57% efficiency at 200 nm gap; and, at 3000 °K, 115 W/cm(2) with ~61% efficiency at 140 nm gap. Key to this striking performance is a novel photonic design forcing the emitter and cell single modes to cros resonantly couple and impedance-match just above the semiconductor bandgap, creating there a 'squeezed' narrowband near-field emission spectrum. Specifically, we employ surface-plasmon-polariton thermal emitters and silver-backed semiconductor-thin-film photovoltaic cells. The emitter planar plasmonic nature allows for high-power and stable high-temperature operation. Our simulations include modeling of free-carrier absorption in both cell electrodes and temperature dependence of the emitter properties. At high temperatures, the efficiency enhancement via resonant mode cross-coupling and matching can be extended to even higher power, by appropriately patterning the silver back electrode to enforce also an absorber effective surface-plasmon-polariton mode. Our proposed designs can therefore lead the way for mass-producible and low-cost ThermoPhotoVoltaic micro-generators and solar cells.

‘Squeezing’ near-field thermal emission for ultra-efficient high-power thermophotovoltaic conversion

PubMed Central

Karalis, Aristeidis; Joannopoulos, J. D.

2016-01-01

We numerically demonstrate near-field planar ThermoPhotoVoltaic systems with very high efficiency and output power, at large vacuum gaps. Example performances include: at 1200 °K emitter temperature, output power density 2 W/cm2 with ~47% efficiency at 300 nm vacuum gap; at 2100 °K, 24 W/cm2 with ~57% efficiency at 200 nm gap; and, at 3000 °K, 115 W/cm2 with ~61% efficiency at 140 nm gap. Key to this striking performance is a novel photonic design forcing the emitter and cell single modes to cros resonantly couple and impedance-match just above the semiconductor bandgap, creating there a ‘squeezed’ narrowband near-field emission spectrum. Specifically, we employ surface-plasmon-polariton thermal emitters and silver-backed semiconductor-thin-film photovoltaic cells. The emitter planar plasmonic nature allows for high-power and stable high-temperature operation. Our simulations include modeling of free-carrier absorption in both cell electrodes and temperature dependence of the emitter properties. At high temperatures, the efficiency enhancement via resonant mode cross-coupling and matching can be extended to even higher power, by appropriately patterning the silver back electrode to enforce also an absorber effective surface-plasmon-polariton mode. Our proposed designs can therefore lead the way for mass-producible and low-cost ThermoPhotoVoltaic micro-generators and solar cells. PMID:27363522

Ion Exchange Formation via Sulfonated Bicomponent Nonwovens

NASA Astrophysics Data System (ADS)

Stoughton, Hannah L.

For many years ion exchange resins were used to: remove heavy metals from water, recover materials from wastewater, and eliminate harmful gases from the air. While use of these resin beads dominates the ion exchange industry, the beads have limitations that should be considered when decisions are made to employ them. For instance, officials must balance the inherent zero sum surface area and porosity of the materials. This series of studies investigates the use of bicomponent nonwovens as a base substrate for producing high surface area ion exchange materials for the removal of heavy metal ions. Functionalized materials were produced in a two-step process: (1) PET/PE spunbond bicomponent fibers were fractured completely, producing the high surface area nonwoven to be used as the base ion exchange material, and (2) the conditions for functionalizing the PET fibers of the nonwoven webs were investigated where an epoxy containing monomer was grafted to the surface followed by sulfonation of the monomer. The functionalization reactions of the PET fibers were monitored based on: weight gain, FTIR, TOF-SIMS, and SEM. Ion exchange properties were evaluated using titration and copper ion removal capacity from test solutions. The relationship between web structure and removal efficiency of the metal ions was defined through a comparison of the bicomponent and homocomponent nonwovens for copper ion removal efficiency. The investigation revealed that utilizing the high surface area, fractured bicomponent nonwoven ion exchange materials with capacities comparable to commercially available ion exchange resins could be produced.

Efficient Array Design for Sonotherapy

PubMed Central

Stephens, Douglas N.; Kruse, Dustin E.; Ergun, Arif S.; Barnes, Stephen; Ming Lu, X.; Ferrara, Katherine

2008-01-01

New linear multi-row, multi-frequency arrays have been designed, constructed and tested as fully operational ultrasound probes to produce confocal imaging and therapeutic acoustic intensities with a standard commercial ultrasound imaging system. The triple-array probes and imaging system produce high quality B-mode images with a center row imaging array at 5.3 MHz, and sufficient acoustic power with dual therapeutic arrays to produce mild hyperthermia at 1.54 MHz. The therapeutic array pair in the first probe design (termed G3) utilizes a high bandwidth and peak pressure, suitable for mechanical therapies. The second multi-array design (termed G4) has a redesigned therapeutic array pair which is optimized for high time-averaged power output suitable for mild hyperthermia applications. The “thermal therapy” design produces more than 4 Watts of acoustic power from the low frequency arrays with only a 10.5 °C internal rise in temperature after 100 seconds of continuous use with an unmodified conventional imaging system, or substantially longer operation at lower acoustic power. The low frequency arrays in both probe designs were examined and contrasted for real power transfer efficiency with a KLM model which includes all lossy contributions in the power delivery path from system transmitters to tissue load. Laboratory verification was successfully performed for the KLM derived estimates of transducer parallel model acoustic resistance and dissipation resistance, which are the critical design factors for acoustic power output and undesired internal heating respectively. PMID:18591737

Constant-pressure Blowers

NASA Technical Reports Server (NTRS)

Sorensen, E

1940-01-01

The conventional axial blowers operate on the high-pressure principle. One drawback of this type of blower is the relatively low pressure head, which one attempts to overcome with axial blowers producing very high pressure at a given circumferential speed. The Schicht constant-pressure blower affords pressure ratios considerably higher than those of axial blowers of conventional design with approximately the same efficiency.

High speed machining of space shuttle external tank liquid hydrogen barrel panel

NASA Technical Reports Server (NTRS)

Hankins, J. D.

1983-01-01

Actual and projected optimum High Speed Machining data for producing shuttle external tank liquid hydrogen barrel panels of aluminum alloy 2219-T87 are reported. The data included various machining parameters; e.g., spindle speeds, cutting speed, table feed, chip load, metal removal rate, horsepower, cutting efficiency, cutter wear (lack of) and chip removal methods.

High speed machining of space shuttle external tank liquid hydrogen barrel panel

NASA Astrophysics Data System (ADS)

Hankins, J. D.

1983-11-01

Actual and projected optimum High Speed Machining data for producing shuttle external tank liquid hydrogen barrel panels of aluminum alloy 2219-T87 are reported. The data included various machining parameters; e.g., spindle speeds, cutting speed, table feed, chip load, metal removal rate, horsepower, cutting efficiency, cutter wear (lack of) and chip removal methods.

Performance characteristics of high-conductivity channel electron multipliers. [as UV and x ray detector

NASA Technical Reports Server (NTRS)

Timothy, J. G.; Bybee, R. L.

1978-01-01

The paper describes a new type of continuous channel multiplier (CEM) fabricated from a low-resistance glass to produce a high-conductivity channel section and thereby obtain a high count-rate capability. The flat-cone cathode configuration of the CEM is specifically designed for the detection of astigmatic exit images from grazing-incidence spectrometers at the optimum angle of illumination for high detection efficiencies at XUV wavelengths. Typical operating voltages are in the range of 2500-2900 V with stable counting plateau slopes in the range 3-6% per 100-V increment. The modal gain at 2800 V was typically in the range (50-80) million. The modal gain falls off at count rates in excess of about 20,000 per sec. The detection efficiency remains essentially constant to count rates in excess of 2 million per sec. Higher detection efficiencies (better than 20%) are obtained by coating the CEM with MgF2. In life tests of coated CEMs, no measurable change in detection efficiency was measured to a total accumulated signal of 2 times 10 to the 11th power counts.

Sustainable and efficient biohydrogen production via electrohydrogenesis.

PubMed

Cheng, Shaoan; Logan, Bruce E

2007-11-20

Hydrogen gas has tremendous potential as an environmentally acceptable energy carrier for vehicles, but most hydrogen is generated from nonrenewable fossil fuels such as natural gas. Here, we show that efficient and sustainable hydrogen production is possible from any type of biodegradable organic matter by electrohydrogenesis. In this process, protons and electrons released by exoelectrogenic bacteria in specially designed reactors (based on modifying microbial fuel cells) are catalyzed to form hydrogen gas through the addition of a small voltage to the circuit. By improving the materials and reactor architecture, hydrogen gas was produced at yields of 2.01-3.95 mol/mol (50-99% of the theoretical maximum) at applied voltages of 0.2 to 0.8 V using acetic acid, a typical dead-end product of glucose or cellulose fermentation. At an applied voltage of 0.6 V, the overall energy efficiency of the process was 288% based solely on electricity applied, and 82% when the heat of combustion of acetic acid was included in the energy balance, at a gas production rate of 1.1 m(3) of H(2) per cubic meter of reactor per day. Direct high-yield hydrogen gas production was further demonstrated by using glucose, several volatile acids (acetic, butyric, lactic, propionic, and valeric), and cellulose at maximum stoichiometric yields of 54-91% and overall energy efficiencies of 64-82%. This electrohydrogenic process thus provides a highly efficient route for producing hydrogen gas from renewable and carbon-neutral biomass resources.

Mesoporous Three-Dimensional Graphene Networks for Highly Efficient Solar Desalination under 1 sun Illumination.

PubMed

Kim, Kwanghyun; Yu, Sunyoung; An, Cheolwon; Kim, Sung-Wook; Jang, Ji-Hyun

2018-05-09

Solar desalination via thermal evaporation of seawater is one of the most promising technologies for addressing the serious problem of global water scarcity because it does not require additional supporting energy other than infinite solar energy for generating clean water. However, low efficiency and a large amount of heat loss are considered critical limitations of solar desalination technology. The combination of mesoporous three-dimensional graphene networks (3DGNs) with a high solar absorption property and water-transporting wood pieces with a thermal insulation property has exhibited greatly enhanced solar-to-vapor conversion efficiency. 3DGN deposited on a wood piece provides an outstanding value of solar-to-vapor conversion efficiency, about 91.8%, under 1 sun illumination and excellent desalination efficiency of 5 orders salinity decrement. The mass-producible 3DGN enriched with many mesopores efficiently releases the vapors from an enormous area of the surface by heat localization on the top surface of the wood piece. Because the efficient solar desalination device made by 3DGN on the wood piece is highly scalable and inexpensive, it could serve as one of the main sources for the worldwide supply of purified water achieved via earth-abundant materials without an extra supporting energy source.

Diffuse-Illumination Systems for Growing Plants

NASA Technical Reports Server (NTRS)

May, George; Ryan, Robert

2010-01-01

Agriculture in both terrestrial and space-controlled environments relies heavily on artificial illumination for efficient photosynthesis. Plant-growth illumination systems require high photon flux in the spectral range corresponding with plant photosynthetic active radiation (PAR) (400 700 nm), high spatial uniformity to promote uniform growth, and high energy efficiency to minimize electricity usage. The proposed plant-growth system takes advantage of the highly diffuse reflective surfaces on the interior of a sphere, hemisphere, or other nearly enclosed structure that is coated with highly reflective materials. This type of surface and structure uniformly mixes discrete light sources to produce highly uniform illumination. Multiple reflections from within the domelike structures are exploited to obtain diffuse illumination, which promotes the efficient reuse of photons that have not yet been absorbed by plants. The highly reflective surfaces encourage only the plant tissue (placed inside the sphere or enclosure) to absorb the light. Discrete light sources, such as light emitting diodes (LEDs), are typically used because of their high efficiency, wavelength selection, and electronically dimmable properties. The light sources are arranged to minimize shadowing and to improve uniformity. Different wavelengths of LEDs (typically blue, green, and red) are used for photosynthesis. Wavelengths outside the PAR range can be added for plant diagnostics or for growth regulation

Full 3D modelling of pulse propagation enables efficient nonlinear frequency conversion with low energy laser pulses in a single-element tripler.

PubMed

Kardaś, Tomasz M; Nejbauer, Michał; Wnuk, Paweł; Resan, Bojan; Radzewicz, Czesław; Wasylczyk, Piotr

2017-02-22

Although new optical materials continue to open up access to more and more wavelength bands where femtosecond laser pulses can be generated, light frequency conversion techniques are still indispensable in filling the gaps on the ultrafast spectral scale. With high repetition rate, low pulse energy laser sources (oscillators) tight focusing is necessary for a robust wave mixing and the efficiency of broadband nonlinear conversion is limited by diffraction as well as spatial and temporal walk-off. Here we demonstrate a miniature third harmonic generator (tripler) with conversion efficiency exceeding 30%, producing 246 fs UV pulses via cascaded second order processes within a single laser beam focus. Designing this highly efficient and ultra compact frequency converter was made possible by full 3-dimentional modelling of propagation of tightly focused, broadband light fields in nonlinear and birefringent media.

Multiple exciton generation for photoelectrochemical hydrogen evolution reactions with quantum yields exceeding 100%

DOE PAGES

Yan, Yong; Crisp, Ryan W.; Gu, Jing; ...

2017-04-03

Multiple exciton generation (MEG) in quantum dots (QDs) has the potential to greatly increase the power conversion efficiency in solar cells and in solar-fuel production. During the MEG process, two electron-hole pairs (excitons) are created from the absorption of one high-energy photon, bypassing hot-carrier cooling via phonon emission. Here we demonstrate that extra carriers produced via MEG can be used to drive a chemical reaction with quantum efficiency above 100%. We developed a lead sulfide (PbS) QD photoelectrochemical cell that is able to drive hydrogen evolution from aqueous Na 2S solution with a peak external quantum efficiency exceeding 100%. QDmore » photoelectrodes that were measured all demonstrated MEG when the incident photon energy was larger than 2.7 times the bandgap energy. Finally, our results demonstrate a new direction in exploring high-efficiency approaches to solar fuels.« less

Full 3D modelling of pulse propagation enables efficient nonlinear frequency conversion with low energy laser pulses in a single-element tripler

NASA Astrophysics Data System (ADS)

Kardaś, Tomasz M.; Nejbauer, Michał; Wnuk, Paweł; Resan, Bojan; Radzewicz, Czesław; Wasylczyk, Piotr

2017-02-01

Although new optical materials continue to open up access to more and more wavelength bands where femtosecond laser pulses can be generated, light frequency conversion techniques are still indispensable in filling the gaps on the ultrafast spectral scale. With high repetition rate, low pulse energy laser sources (oscillators) tight focusing is necessary for a robust wave mixing and the efficiency of broadband nonlinear conversion is limited by diffraction as well as spatial and temporal walk-off. Here we demonstrate a miniature third harmonic generator (tripler) with conversion efficiency exceeding 30%, producing 246 fs UV pulses via cascaded second order processes within a single laser beam focus. Designing this highly efficient and ultra compact frequency converter was made possible by full 3-dimentional modelling of propagation of tightly focused, broadband light fields in nonlinear and birefringent media.

Synthesis of chemicals using solar energy with stable photoelectrochemically active heterostructures.

PubMed

Mubeen, Syed; Singh, Nirala; Lee, Joun; Stucky, Galen D; Moskovits, Martin; McFarland, Eric W

2013-05-08

Efficient and cost-effective conversion of solar energy to useful chemicals and fuels could lead to a significant reduction in fossil hydrocarbon use. Artificial systems that use solar energy to produce chemicals have been reported for more than a century. However the most efficient devices demonstrated, based on traditionally fabricated compound semiconductors, have extremely short working lifetimes due to photocorrosion by the electrolyte. Here we report a stable, scalable design and molecular level fabrication strategy to create photoelectrochemically active heterostructure (PAH) units consisting of an efficient semiconductor light absorber in contact with oxidation and reduction electrocatalysts and otherwise protected by alumina. The functional heterostructures are fabricated by layer-by-layer, template-directed, electrochemical synthesis in porous anodic aluminum oxide membranes to produce high density arrays of electronically autonomous, nanostructured, corrosion resistant, photoactive units (~10(9)-10(10) PAHs per cm(2)). Each PAH unit is isolated from its neighbor by the transparent electrically insulating oxide cellular enclosure that makes the overall assembly fault tolerant. When illuminated with visible light, the free floating devices have been demonstrated to produce hydrogen at a stable rate for over 24 h in corrosive hydroiodic acid electrolyte with light as the only input. The quantum efficiency (averaged over the solar spectrum) for absorbed photons-to-hydrogen conversion was 7.4% and solar-to-hydrogen energy efficiency of incident light was 0.9%. The fabrication approach is scalable for commercial manufacturing and readily adaptable to a variety of earth abundant semiconductors which might otherwise be unstable as photoelectrocatalysts.

Assessment of Palm Press Fibre and Sawdust-Based Substrate Formulas for Efficient Carpophore Production of Lentinus squarrosulus (Mont.) Singer

PubMed Central

Chiejina, Nneka Virginia

2015-01-01

Development of efficient substrate formulas to improve yield and shorten production time is one of the prerequisites for commercial cultivation of edible mushrooms. In this study, fifteen substrate formulas consisting of varying ratios of palm press fibre (PPF), mahogany sawdust (MS), Gmelina sawdust, wheat bran (WB), and fixed proportions of 1% calcium carbonate (CaCO3) and 1% sucrose were assessed for efficient Lentinus squarrosulus production. Proximate compositions of mushrooms produced on the different substrate formulas were also analysed and compared. Substrate formulations containing 85% PPF, 13% WB, 1% CaCO3, and 1% sucrose were found to produce the highest carpophore yield, biological efficiency and size (206.5 g/kg, 61.96%, and 7.26 g, respectively). Days to production (first harvest) tended to increase with an increase in the amount of WB in the substrate formulas, except for PPF based formulas. The addition of WB in amounts equivalent to 8~18% in substrate formulas containing 80~90% PPF resulted in a decrease in the time to first harvest by an average of 17.7 days compared to 80~90% MS with similar treatment. Nutritional content of mushrooms was affected by the different substrate formulas. Protein content was high for mushrooms produced on formulas containing PPF as the basal substrate. Thus, formulas comprising PPF, WB, CaCO3, and sucrose at 85% : 13% : 1% : 1%) respectively could be explored as starter basal ingredients for efficient large scale production of L. squarrosulus. PMID:26839507

1W frequency-doubled VCSEL-pumped blue laser with high pulse energy

NASA Astrophysics Data System (ADS)

Van Leeuwen, Robert; Chen, Tong; Watkins, Laurence; Xu, Guoyang; Seurin, Jean-Francois; Wang, Qing; Zhou, Delai; Ghosh, Chuni

2015-02-01

We report on a Q-switched VCSEL side-pumped 946 nm Nd:YAG laser that produces high average power blue light with high pulse energy after frequency doubling in BBO. The gain medium was water cooled and symmetrically pumped by three 1 kW 808 nm VCSEL pump modules. More than 1 W blue output was achieved at 210 Hz with 4.9 mJ pulse energy and at 340 Hz with 3.2 mJ pulse energy, with 42% and 36% second harmonic conversion efficiency respectively. Higher pulse energy was obtained at lower repetition frequencies, up to 9.3 mJ at 70 Hz with 52% conversion efficiency.

Extended cage adjustable speed electric motors and drive packages

DOEpatents

Hsu, J.S.

1999-03-23

The rotor cage of a motor is extended, a second stator is coupled to this extended rotor cage, and the windings have the same number of poles. The motor torque and speed can be controlled by either injecting energy into or extracting energy out from the rotor cage. The motor produces less harmonics than existing doubly-fed motors. Consequently, a new type of low cost, high efficiency drive is produced. 12 figs.

Efficient preparation of enantiopure D-phenylalanine through asymmetric resolution using immobilized phenylalanine ammonia-lyase from Rhodotorula glutinis JN-1 in a recirculating packed-bed reactor.

PubMed

Zhu, Longbao; Zhou, Li; Huang, Nan; Cui, Wenjing; Liu, Zhongmei; Xiao, Ke; Zhou, Zhemin

2014-01-01

An efficient enzymatic process was developed to produce optically pure D-phenylalanine through asymmetric resolution of the racemic DL-phenylalanine using immobilized phenylalanine ammonia-lyase (RgPAL) from Rhodotorula glutinis JN-1. RgPAL was immobilized on a modified mesoporous silica support (MCM-41-NH-GA). The resulting MCM-41-NH-GA-RgPAL showed high activity and stability. The resolution efficiency using MCM-41-NH-GA-RgPAL in a recirculating packed-bed reactor (RPBR) was higher than that in a stirred-tank reactor. Under optimal operational conditions, the volumetric conversion rate of L-phenylalanine and the productivity of D-phenylalanine reached 96.7 mM h⁻¹ and 0.32 g L⁻¹ h⁻¹, respectively. The optical purity (eeD) of D-phenylalanine exceeded 99%. The RPBR ran continuously for 16 batches, the conversion ratio did not decrease. The reactor was scaled up 25-fold, and the productivity of D-phenylalanine (eeD>99%) in the scaled-up reactor reached 7.2 g L⁻¹ h⁻¹. These results suggest that the resolution process is an alternative method to produce highly pure D-phenylalanine.

Efficient Preparation of Enantiopure D-Phenylalanine through Asymmetric Resolution Using Immobilized Phenylalanine Ammonia-Lyase from Rhodotorula glutinis JN-1 in a Recirculating Packed-Bed Reactor

PubMed Central

Huang, Nan; Cui, Wenjing; Liu, Zhongmei; Xiao, Ke; Zhou, Zhemin

2014-01-01

An efficient enzymatic process was developed to produce optically pure D-phenylalanine through asymmetric resolution of the racemic DL-phenylalanine using immobilized phenylalanine ammonia-lyase (RgPAL) from Rhodotorula glutinis JN-1. RgPAL was immobilized on a modified mesoporous silica support (MCM-41-NH-GA). The resulting MCM-41-NH-GA-RgPAL showed high activity and stability. The resolution efficiency using MCM-41-NH-GA-RgPAL in a recirculating packed-bed reactor (RPBR) was higher than that in a stirred-tank reactor. Under optimal operational conditions, the volumetric conversion rate of L-phenylalanine and the productivity of D-phenylalanine reached 96.7 mM h−1 and 0.32 g L−1 h−1, respectively. The optical purity (ee D) of D-phenylalanine exceeded 99%. The RPBR ran continuously for 16 batches, the conversion ratio did not decrease. The reactor was scaled up 25-fold, and the productivity of D-phenylalanine (ee D>99%) in the scaled-up reactor reached 7.2 g L−1 h−1. These results suggest that the resolution process is an alternative method to produce highly pure D-phenylalanine. PMID:25268937

Different Efficiency of Liposomal Forms with Hydrophilic and Hydrophobic Antitumor Agents in Relation to Solid Transplants of Mouse Tumor and Its Metastases in the Liver.

PubMed

Popova, N A; Kaledin, V I; Nikolin, V P; Bogdanova, L A; Morozkova, T S; Tornuev, Yu V

2016-10-01

Experiments were performed on the model of transplanted mouse tumor with high incidence of liver metastases. Hydrophilic drug cycloplatam (injected intravenously in liposomes) was more potent than "free cycloplatam" (injected intravenously or intraperitoneally in physiological saline) in inhibiting the growth of natural and experimental metastases in the liver. By contrast, liposomal cycloplatam had lower efficiency than free cycloplatam in suppressing the growth of solid tumor. Liposomal and free cortifen (hydrophobic hormonal cytostatic) produced nearly the same effects on solid tumor growth. Our results suggest that liposomal forms of hydrophobic compounds producing nonselective effect on tumor cells (e.g., actinomycin D or Cosmegen), should not have advantages over free forms.

Comparative behaviour of yeast strains for ethanolic fermentation of culled apple juice.

PubMed

Modi, D R; Garg, S K; Johri, B N

1998-07-01

The culled apple juice contained (% w/v): nitrogen, 0.036; total sugars, 11.6 and was of pH 3.9. Saccharomyces cerevisiae NCIM 3284, Pichia kluyeri and Candida krusei produced more ethanol from culled apple juice at its optimum initial pH 4.5, whereas S. cerevisiae NCIM 3316 did so at pH 5.0. An increase in sugar concentration of apple juice from natural 11.6% to 20% exhibited enhanced ethanol production and improved fermentation efficiency of both the S. cerevisiae strains, whereas P. kluyveri and C. krusei produced high ethanol at 11.6% and 16.0% sugar levels, respectively. Urea was stimulatory for ethanol production as well as fermentation efficiency of the yeast strains under study.

Papaya (Carica papaya L.).

PubMed

Zhu, Yun J; Fitch, Maureen M M; Moore, Paul H

2006-01-01

Transgenic papaya plants were initially obtained using particle bombardment, a method having poor efficiency in producing intact, single-copy insertion of transgenes. Single-copy gene insertion was improved using Agrobacterium tumefaciens. With progress being made in genome sequencing and gene discovery, there is a need for more efficient methods of transformation in order to study the function of these genes. We describe a protocol for Agrobacterium-mediated transformation using carborundum-wounded papaya embryogenic calli. This method should lead to high-throughput transformation, which on average produced at least one plant that was positive in polymerase chain reaction (PCR), histochemical staining, or by Southern blot hybridization from 10 to 20% of the callus clusters that had been co-cultivated with Agrobacterium. Plants regenerated from the callus clusters in 9 to 13 mo.

Airfoil Design and Optimization by the One-Shot Method

NASA Technical Reports Server (NTRS)

Kuruvila, G.; Taasan, Shlomo; Salas, M. D.

1995-01-01

An efficient numerical approach for the design of optimal aerodynamic shapes is presented in this paper. The objective of any optimization problem is to find the optimum of a cost function subject to a certain state equation (governing equation of the flow field) and certain side constraints. As in classical optimal control methods, the present approach introduces a costate variable (Lagrange multiplier) to evaluate the gradient of the cost function. High efficiency in reaching the optimum solution is achieved by using a multigrid technique and updating the shape in a hierarchical manner such that smooth (low-frequency) changes are done separately from high-frequency changes. Thus, the design variables are changed on a grid where their changes produce nonsmooth (high-frequency) perturbations that can be damped efficiently by the multigrid. The cost of solving the optimization problem is approximately two to three times the cost of the equivalent analysis problem.

Topology-optimized metasurfaces: impact of initial geometric layout.

PubMed

Yang, Jianji; Fan, Jonathan A

2017-08-15

Topology optimization is a powerful iterative inverse design technique in metasurface engineering and can transform an initial layout into a high-performance device. With this method, devices are optimized within a local design phase space, making the identification of suitable initial geometries essential. In this Letter, we examine the impact of initial geometric layout on the performance of large-angle (75 deg) topology-optimized metagrating deflectors. We find that when conventional metasurface designs based on dielectric nanoposts are used as initial layouts for topology optimization, the final devices have efficiencies around 65%. In contrast, when random initial layouts are used, the final devices have ultra-high efficiencies that can reach 94%. Our numerical experiments suggest that device topologies based on conventional metasurface designs may not be suitable to produce ultra-high-efficiency, large-angle metasurfaces. Rather, initial geometric layouts with non-trivial topologies and shapes are required.

High efficiency laser-assisted H - charge exchange for microsecond duration beams

DOE PAGES

Cousineau, Sarah; Rakhman, Abdurahim; Kay, Martin; ...

2017-12-26

Laser-assisted stripping is a novel approach to H - charge exchange that overcomes long-standing limitations associated with the traditional, foil-based method of producing high-intensity, time-structured beams of protons. This paper reports on the first successful demonstration of the laser stripping technique for microsecond duration beams. The experiment represents a factor of 1000 increase in the stripped pulse duration compared with the previous proof-of-principle demonstration. The central theme of the experiment is the implementation of methods to reduce the required average laser power such that high efficiency stripping can be accomplished for microsecond duration beams using conventional laser technology. In conclusion,more » the experiment was performed on the Spallation Neutron Source 1 GeV H - beam using a 1 MW peak power UV laser and resulted in ~95% stripping efficiency.« less

High efficiency laser-assisted H - charge exchange for microsecond duration beams

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

Cousineau, Sarah; Rakhman, Abdurahim; Kay, Martin

Laser-assisted stripping is a novel approach to H - charge exchange that overcomes long-standing limitations associated with the traditional, foil-based method of producing high-intensity, time-structured beams of protons. This paper reports on the first successful demonstration of the laser stripping technique for microsecond duration beams. The experiment represents a factor of 1000 increase in the stripped pulse duration compared with the previous proof-of-principle demonstration. The central theme of the experiment is the implementation of methods to reduce the required average laser power such that high efficiency stripping can be accomplished for microsecond duration beams using conventional laser technology. In conclusion,more » the experiment was performed on the Spallation Neutron Source 1 GeV H - beam using a 1 MW peak power UV laser and resulted in ~95% stripping efficiency.« less

Airfoil optimization by the one-shot method

NASA Technical Reports Server (NTRS)

Kuruvila, G.; Taasan, Shlomo; Salas, M. D.

1994-01-01

An efficient numerical approach for the design of optimal aerodynamic shapes is presented in this paper. The objective of any optimization problem is to find the optimum of a cost function subject to a certain state equation (Governing equation of the flow field) and certain side constraints. As in classical optimal control methods, the present approach introduces a costate variable (Language multiplier) to evaluate the gradient of the cost function. High efficiency in reaching the optimum solution is achieved by using a multigrid technique and updating the shape in a hierarchical manner such that smooth (low-frequency) changes are done separately from high-frequency changes. Thus, the design variables are changed on a grid where their changes produce nonsmooth (high-frequency) perturbations that can be damped efficiently by the multigrid. The cost of solving the optimization problem is approximately two to three times the cost of the equivalent analysis problem.

Efficient Removal of Arsenic and Antimony During Blast Furnace Smelting of Lead-Containing Materials

NASA Astrophysics Data System (ADS)

Dosmukhamedov, Nurlan; Kaplan, Valery

2017-02-01

The efficient removal of impurities, As and Sb, from recycled lead-containing materials is a key issue in the selection of the appropriate smelting technology for projects involving metal reuse. Volatilization of impurities such as As and Sb should occur as early as possible in the process, and preferably within the smelting furnace, so that they do not contaminate the industrial environment nor interfere with the operation of downstream equipment. Using of copper-zinc concentrates in the blast furnace process for recycling lead-containing materials achieves: (1) high copper extraction to matte; (2) high lead extraction to lead bullion; and (3) high zinc extraction to slag, while at the same time producing a more efficient volatilization of As and Sb. Based on both laboratory and industrial data and thermodynamic considerations, the advantages of this blast furnace process for the treatment of recycled lead-containing materials are discussed.

Yb:YAG ceramic-based laser driver for Inertial Fusion Energy (IFE)

NASA Astrophysics Data System (ADS)

Vetrovec, John; Copeland, Drew A.; Litt, Amardeep S.

2016-03-01

We report on a new class of laser amplifiers for inertial confinement fusion (ICF) drivers based on a Yb:YAG ceramic disk in an edge-pumped configuration and cooled by a high-velocity gas flow. The Yb lasant offers very high efficiency and low waste heat. The ceramic host material has a thermal conductivity nearly 15-times higher than the traditionally used glass and it is producible in sizes suitable for a typical 10- to 20-kJ driver beam line. The combination of high lasant efficiency, low waste heat, edge-pumping, and excellent thermal conductivity of the host, enable operation at 10 to 20 Hz at over 20% wall plug efficiency while being comparably smaller and less costly than recently considered face-pumped alternative drivers using Nd:glass, Yb:S-FAP, and cryogenic Yb:YAG. Scalability of the laser driver over a broad range of sizes is presented.

Efficient free fatty acid production in engineered Escherichia coli strains using soybean oligosaccharides as feedstock.

PubMed

Wang, Dan; Wu, Hui; Thakker, Chandresh; Beyersdorf, Jared; Bennett, George N; San, Ka-Yiu

2015-01-01

To be competitive with current petrochemicals, microbial synthesis of free fatty acids can be made to rely on a variety of renewable resources rather than on food carbon sources, which increase its attraction for governments and companies. Industrial waste soybean meal is an inexpensive feedstock, which contains soluble sugars such as stachyose, raffinose, sucrose, glucose, galactose, and fructose. Free fatty acids were produced in this report by introducing an acyl-ACP carrier protein thioesterase and (3R)-hydroxyacyl-ACP dehydratase into E. coli. Plasmid pRU600 bearing genes involved in raffinose and sucrose metabolism was also transformed into engineered E. coli strains, which allowed more efficient utilization of these two kinds of specific oligosaccharide present in the soybean meal extract. Strain ML103 (pRU600, pXZ18Z) produced ~1.60 and 2.66 g/L of free fatty acids on sucrose and raffinose, respectively. A higher level of 2.92 g/L fatty acids was obtained on sugar mixture. The fatty acid production using hydrolysate obtained from acid or enzyme based hydrolysis was evaluated. Engineered strains just produced ~0.21 g/L of free fatty acids with soybean meal acid hydrolysate. However, a fatty acid production of 2.61 g/L with a high yield of 0.19 g/g total sugar was observed on an enzymatic hydrolysate. The results suggest that complex mixtures of oligosaccharides derived from soybean meal can serve as viable feedstock to produce free fatty acids. Enzymatic hydrolysis acts as a much more efficient treatment than acid hydrolysis to facilitate the transformation of industrial waste from soybean processing to high value added chemicals. © 2015 American Institute of Chemical Engineers.

Precise Perforation and Scalable Production of Si Particles from Low-Grade Sources for High-Performance Lithium Ion Battery Anodes.

PubMed

Zong, Linqi; Jin, Yan; Liu, Chang; Zhu, Bin; Hu, Xiaozhen; Lu, Zhenda; Zhu, Jia

2016-11-09

Alloy anodes, particularly silicon, have been intensively pursued as one of the most promising anode materials for the next generation lithium-ion battery primarily because of high specific capacity (>4000 mAh/g) and elemental abundance. In the past decade, various nanostructures with porosity or void space designs have been demonstrated to be effective to accommodate large volume expansion (∼300%) and to provide stable solid electrolyte interphase (SEI) during electrochemical cycling. However, how to produce these building blocks with precise morphology control at large scale and low cost remains a challenge. In addition, most of nanostructured silicon suffers from poor Coulombic efficiency due to a large surface area and Li ion trapping at the surface coating. Here we demonstrate a unique nanoperforation process, combining modified ball milling, annealing, and acid treating, to produce porous Si with precise and continuous porosity control (from 17% to 70%), directly from low cost metallurgical silicon source (99% purity, ∼ $1/kg). The produced porous Si coated with graphene by simple ball milling can deliver a reversible specific capacity of 1250 mAh/g over 1000 cycles at the rate of 1C, with Coulombic efficiency of first cycle over 89.5%. The porous networks also provide efficient ion and electron pathways and therefore enable excellent rate performance of 880 mAh/g at the rate of 5C. Being able to produce particles with precise porosity control through scalable processes from low-grade materials, it is expected that this nanoperforation may play a role in the next generation lithium ion battery anodes, as well as many other potential applications such as optoelectronics and thermoelectrics.

Management of enzyme diversity in high-performance cellulolytic cocktails.

PubMed

Reyes-Sosa, Francisco Manuel; López Morales, Macarena; Platero Gómez, Ana Isabel; Valbuena Crespo, Noelia; Sánchez Zamorano, Laura; Rocha-Martín, Javier; Molina-Heredia, Fernando P; Díez García, Bruno

2017-01-01

Modern biorefineries require enzymatic cocktails of improved efficiency to generate fermentable sugars from lignocellulosic biomass. Cellulolytic fungi, among other microorganisms, have demonstrated the highest potential in terms of enzymatic productivity, complexity and efficiency. On the other hand, under cellulolytic-inducing conditions, they often produce a considerable diversity of carbohydrate-active enzymes which allow them to adapt to changing environmental conditions. However, industrial conditions are fixed and adjusted to the optimum of the whole cocktail, resulting in underperformance of individual enzymes. One of these cellulolytic cocktails from Myceliophthora thermophila has been analyzed here by means of LC-MS/MS. Pure GH6 family members detected have been characterized, confirming previous studies, and added to whole cocktails to compare their contribution in the hydrolysis of industrial substrates. Finally, independent deletions of two GH6 family members, as an example of the enzymatic diversity management, led to the development of a strain producing a more efficient cellulolytic cocktail. These data indicate that the deletion of noncontributive cellulases (here EG VI) can increase the cellulolytic efficiency of the cocktail, validating the management of cellulase diversity as a strategy to obtain improved fungal cellulolytic cocktails.

Development of high efficiency Versatile Arc Discharge Ion Source at CERN ISOLDE.

PubMed

Penescu, L; Catherall, R; Lettry, J; Stora, T

2010-02-01

We report here recent developments of Forced Electron Beam Induced Arc Discharge (FEBIAD) ion sources at the ISOLDE radioactive ion beam facility, hosted at the European Organization for Nuclear Research (CERN). As a result of the propositions to improve the ionization efficiency, two FEBIAD prototypes have been produced and successfully tested in 2008. Off-line studies showed that the 1+ ionization efficiencies for noble gases are 5-20 times larger than with the standard ISOLDE FEBIAD ion sources and reach 60% for radon, which allowed the identification at ISOLDE of (229)Rn, an isotope that had never previously been observed in the laboratory. A factor of 3 increase is also expected for the ionization efficiency of the other elements. The experimental and theoretical methodology is presented. The theoretical model, which gives precise insights on the processes affecting the ionization, is used to design optimal sources (grouped under the name of VADIS--Versatile Arc Discharge Ion Source) for the different chemical classes of the produced isotopes, as already demonstrated for the noble gases.

Highly efficient reversible addition-fragmentation chain-transfer polymerization in ethanol/water via flow chemistry

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

Ye, Piaoran; Cao, Peng -Fei; Su, Zhe

Here, utilization of a flow reactor under high pressure allows highly efficient polymer synthesis via reversible addition–fragmentation chain-transfer (RAFT) polymerization in an aqueous system. Compared with the batch reaction, the flow reactor allows the RAFT polymerization to be performed in a high-efficiency manner at the same temperature. The adjustable pressure of the system allows further elevation of the reaction temperature and hence faster polymerization. Other reaction parameters, such as flow rate and initiator concentration, were also well studied to tune the monomer conversion and the molar mass dispersity (Ð) of the obtained polymers. Gel permeation chromatography, nuclear magnetic resonance (NMR),more » and Fourier transform infrared spectroscopies (FTIR) were utilized to monitor the polymerization process. With the initiator concentration of 0.15 mmol L –1, polymerization of poly(ethylene glycol) methyl ethermethacrylate with monomer conversion of 52% at 100 °C under 73 bar can be achieved within 40 min with narrow molar mass dispersity (D) Ð (<1.25). The strategy developed here provides a method to produce well-defined polymers via RAFT polymerization with high efficiency in a continuous manner.« less

Co- and defect-rich carbon nanofiber films as a highly efficient electrocatalyst for oxygen reduction

NASA Astrophysics Data System (ADS)

Kim, Il To; Song, Myeong Jun; Shin, Seoyoon; Shin, Moo Whan

2018-03-01

Many efforts are continuously devoted to developing high-efficiency, low-cost, and highly scalable oxygen reduction reaction (ORR) electrocatalysts to replace precious metal catalysts. Herein, we successfully synthesize Co- and defect-rich carbon nanofibers (CNFs) using an efficient heat treatment approach involving the pyrolysis of electrospun fibers at 370 °C under air. The heat treatment process produces Co-decorated CNFs with a high Co mass ratio, enriched pyridinic N, Co-pyridinic Nx clusters, and defect-rich carbon structures. The synergistic effects from composition and structural changes in the designed material increase the number of catalytically active sites for the ORR in an alkaline solution. The prepared Co- and defect-rich CNFs exhibit excellent ORR activities with a high ORR onset potential (0.954 V vs. RHE), a large reduction current density (4.426 mA cm-2 at 0.40 V), and a nearly four-electron pathway. The catalyst also exhibits a better long-term durability than commercial Pt/C catalysts. This study provides a novel hybrid material as an efficient ORR catalyst and important insight into the design strategy for CNF-based hybrid materials as electrochemical electrodes.

Genome mining of astaxanthin biosynthetic genes from Sphingomonas sp. ATCC 55669 for heterologous overproduction in Escherichia coli.

PubMed

Ma, Tian; Zhou, Yuanjie; Li, Xiaowei; Zhu, Fayin; Cheng, Yongbo; Liu, Yi; Deng, Zixin; Liu, Tiangang

2016-02-01

As a highly valued keto-carotenoid, astaxanthin is widely used in nutritional supplements and pharmaceuticals. Therefore, the demand for biosynthetic astaxanthin and improved efficiency of astaxanthin biosynthesis has driven the investigation of metabolic engineering of native astaxanthin producers and heterologous hosts. However, microbial resources for astaxanthin are limited. In this study, we found that the α-Proteobacterium Sphingomonas sp. ATCC 55669 could produce astaxanthin naturally. We used whole-genome sequencing to identify the astaxanthin biosynthetic pathway using a combined PacBio-Illumina approach. The putative astaxanthin biosynthetic pathway in Sphingomonas sp. ATCC 55669 was predicted. For further confirmation, a high-efficiency targeted engineering carotenoid synthesis platform was constructed in E. coli for identifying the functional roles of candidate genes. All genes involved in astaxanthin biosynthesis showed discrete distributions on the chromosome. Moreover, the overexpression of exogenous E. coli idi in Sphingomonas sp. ATCC 55669 increased astaxanthin production by 5.4-fold. This study described a new astaxanthin producer and provided more biosynthesis components for bioengineering of astaxanthin in the future. © 2015 The Authors. Biotechnology Journal published by WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Development of high efficiency ball-bearing turbocharger

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

Miyashita, K.; Kurasawa, M.; Matsuoka, H.

1987-01-01

Turbochargers have become very popular on passenger cars since the first mass-produced turbocharged passenger cars were put on market in Japan in 1979. Turbo lag is one of the most serious problem since the first mass-production started. Several new technologies such as a variable geometry turbocharger, ceramic turbocharger, etc. have been introduced to improve acceleration performance. A variable geometry turbocharger changes the area of gas flow passage and increases exhaust gas speed at low engine speed. A ceramic turbocharger reduces inertia moment of a turbine wheel and shaft. Turbocharger mechanical efficiency has equal importance as compressor efficiency and turbine efficiency.more » This paper describes the test results of ball bearing turbochargers.« less

Inducing Stable α + β Microstructures during Selective Laser Melting of Ti-6Al-4V Using Intensified Intrinsic Heat Treatments.

PubMed

Barriobero-Vila, Pere; Gussone, Joachim; Haubrich, Jan; Sandlöbes, Stefanie; Da Silva, Julio Cesar; Cloetens, Peter; Schell, Norbert; Requena, Guillermo

2017-03-07

Selective laser melting is a promising powder-bed-based additive manufacturing technique for titanium alloys: near net-shaped metallic components can be produced with high resource-efficiency and cost savings [...].

High-throughput assay for optimising microbial biological control agent production and delivery

USDA-ARS?s Scientific Manuscript database

Lack of technologies to produce and deliver effective biological control agents (BCAs) is a major barrier to their commercialization. A myriad of variables associated with BCA cultivation, formulation, drying, storage, and reconstitution processes complicates agent quality maximization. An efficie...

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.

Laser-guided energetic discharges over large air gaps by electric-field enhanced plasma filaments

NASA Astrophysics Data System (ADS)

Théberge, Francis; Daigle, Jean-François; Kieffer, Jean-Claude; Vidal, François; Châteauneuf, Marc

2017-01-01

Recent works on plasma channels produced during the propagation of ultrashort and intense laser pulses in air demonstrated the guiding of electric discharges along the laser path. However, the short plasma lifetime limits the length of the laser-guided discharge. In this paper, the conductivity and lifetime of long plasma channels produced by ultrashort laser pulses is enhanced efficiently over many orders of magnitude by the electric field of a hybrid AC-DC high-voltage source. The AC electric pulse from a Tesla coil allowed to stimulate and maintain the highly conductive channel during few milliseconds in order to guide a subsequent 500 times more energetic discharge from a 30-kV DC source. This DC discharge was laser-guided over an air gap length of two metres, which is more than two orders of magnitude longer than the expected natural discharge length. Long plasma channel induced by laser pulses and stimulated by an external high-voltage source opens the way for wireless and efficient transportation of energetic current pulses over long air gaps and potentially for guiding lightning.

Jerusalem artichoke powder: a useful material in producing high-optical-purity l-lactate using an efficient sugar-utilizing thermophilic Bacillus coagulans strain.

PubMed

Wang, Limin; Xue, Zhangwei; Zhao, Bo; Yu, Bo; Xu, Ping; Ma, Yanhe

2013-02-01

Jerusalem artichoke is a low-requirement crop, which does not interfere with food chain, and is a promising carbon source for industrial fermentation. Microbial conversion of such a renewable raw material to useful products, such as lactic acid, is an important objective in industrial biotechnology. In this study, high-optical-purity l-lactate was efficiently produced from the hydrolysates of Jerusalem artichoke powder by a thermophilic bacterium, Bacillus coagulans XZL4. High l-lactate production (134gl(-1)) was obtained using 267gl(-1) Jerusalem artichoke powder (total reducing sugars of 140gl(-1)) and 10gl(-1) of corn steep powder in fed-batch fermentation, with an average productivity of 2.5gl(-1)h(-1) and a yield of 0.96gg(-1) reducing sugars. The final product optical purity is 99%, which meets the requirement of lactic acid polymerization. Our study represents a cost-effective and promising method for polymer-grade l-lactate production using a cheap raw bio-resource. Copyright © 2012 Elsevier Ltd. All rights reserved.

Variable Pitch Darrieus Water Turbines

NASA Astrophysics Data System (ADS)

Kirke, Brian; Lazauskas, Leo

In recent years the Darrieus wind turbine concept has been adapted for use in water, either as a hydrokinetic turbine converting the kinetic energy of a moving fluid in open flow like an underwater wind turbine, or in a low head or ducted arrangement where flow is confined, streamtube expansion is controlled and efficiency is not subject to the Betz limit. Conventional fixed pitch Darrieus turbines suffer from two drawbacks, (i) low starting torque and (ii) shaking due to cyclical variations in blade angle of attack. Ventilation and cavitation can also cause problems in water turbines when blade velocities are high. Shaking can be largely overcome by the use of helical blades, but these do not produce large starting torque. Variable pitch can produce high starting torque and high efficiency, and by suitable choice of pitch regime, shaking can be minimized but not entirely eliminated. Ventilation can be prevented by avoiding operation close to a free surface, and cavitation can be prevented by limiting blade velocities. This paper summarizes recent developments in Darrieus water turbines, some problems and some possible solutions.

Multi-messenger Light Curves from Gamma-Ray Bursts in the Internal Shock Model

NASA Astrophysics Data System (ADS)

Bustamante, Mauricio; Heinze, Jonas; Murase, Kohta; Winter, Walter

2017-03-01

Gamma-ray bursts (GRBs) are promising as sources of neutrinos and cosmic rays. In the internal shock scenario, blobs of plasma emitted from a central engine collide within a relativistic jet and form shocks, leading to particle acceleration and emission. Motivated by present experimental constraints and sensitivities, we improve the predictions of particle emission by investigating time-dependent effects from multiple shocks. We produce synthetic light curves with different variability timescales that stem from properties of the central engine. For individual GRBs, qualitative conclusions about model parameters, neutrino production efficiency, and delays in high-energy gamma-rays can be deduced from inspection of the gamma-ray light curves. GRBs with fast time variability without additional prominent pulse structure tend to be efficient neutrino emitters, whereas GRBs with fast variability modulated by a broad pulse structure can be inefficient neutrino emitters and produce delayed high-energy gamma-ray signals. Our results can be applied to quantitative tests of the GRB origin of ultra-high-energy cosmic rays, and have the potential to impact current and future multi-messenger searches.

Plasmoid Thruster for High Specific-Impulse Propulsion

NASA Technical Reports Server (NTRS)

Fimognari, Peter; Eskridge, Richard; Martin, Adam; Lee, Michael

2007-01-01

A report discusses a new multi-turn, multi-lead design for the first generation PT-1 (Plasmoid Thruster) that produces thrust by expelling plasmas with embedded magnetic fields (plasmoids) at high velocities. This thruster is completely electrodeless, capable of using in-situ resources, and offers efficiencies as high as 70 percent at a specific impulse, I(sub sp), of up to 8,000 s. This unit consists of drive and bias coils wound around a ceramic form, and the capacitor bank and switches are an integral part of the assembly. Multiple thrusters may be gauged to inductively recapture unused energy to boost efficiency and to increase the repetition rate, which, in turn increases the average thrust of the system. The thruster assembly can use storable propellants such as H2O, ammonia, and NO, among others. Any available propellant gases can be used to produce an I(sub sp) in the range of 2,000 to 8,000 s with a single-stage thruster. These capabilities will allow the transport of greater payloads to outer planets, especially in the case of an I(sub sp) greater than 6,000 s.

The influence of metal speciation in combustion waste on the efficiency of Cu, Pb, Zn, Cd, Ni and Cr bioleaching in a mixed culture of sulfur-oxidizing and biosurfactant-producing bacteria.

PubMed

Karwowska, Ewa; Wojtkowska, Małgorzata; Andrzejewska, Dorota

2015-12-15

Metal leachability from ash and combustion slag is related to the physico-chemical properties, including their speciation in the waste. Metals speciation is an important factor that influences the efficiency of metal bioleaching from combustion wastes in a mixed culture of acidophilic and biosurfactant-producing bacteria. It was observed that individual metals tended to occur in different fractions, which reflects their susceptibility to bioleaching. Cr and Ni were readily removed from wastes when present with a high fraction bound to carbonates. Cd and Pb where not effectively bioleached when present in high amounts in a fraction bound to organic matter. The best bioleaching results were obtained for power plant slag, which had a high metal content in the exchangeable, bound to carbonates and bound to Fe and Mg oxides fractions- the metal recovery percentage for Zn, Cu and Ni from this waste exceeded 90%. Copyright © 2015 Elsevier B.V. All rights reserved.

Laser-guided energetic discharges over large air gaps by electric-field enhanced plasma filaments

PubMed Central

Théberge, Francis; Daigle, Jean-François; Kieffer, Jean-Claude; Vidal, François; Châteauneuf , Marc

2017-01-01

Recent works on plasma channels produced during the propagation of ultrashort and intense laser pulses in air demonstrated the guiding of electric discharges along the laser path. However, the short plasma lifetime limits the length of the laser-guided discharge. In this paper, the conductivity and lifetime of long plasma channels produced by ultrashort laser pulses is enhanced efficiently over many orders of magnitude by the electric field of a hybrid AC-DC high-voltage source. The AC electric pulse from a Tesla coil allowed to stimulate and maintain the highly conductive channel during few milliseconds in order to guide a subsequent 500 times more energetic discharge from a 30-kV DC source. This DC discharge was laser-guided over an air gap length of two metres, which is more than two orders of magnitude longer than the expected natural discharge length. Long plasma channel induced by laser pulses and stimulated by an external high-voltage source opens the way for wireless and efficient transportation of energetic current pulses over long air gaps and potentially for guiding lightning. PMID:28053312

One-pot exfoliation, functionalization, and size manipulation of graphene sheets: efficient system for biomedical applications.

PubMed

Bani, Farhad; Bodaghi, Ali; Dadkhah, Abbas; Movahedi, Soodabeh; Bodaghabadi, Narges; Sadeghizadeh, Majid; Adeli, Mohsen

2018-05-01

In this work, we reported a facile method to produce stable aqueous graphene dispersion through direct exfoliation of graphite by modified hyperbranched polyglycerol. Size of graphene sheets was manipulated by simultaneous exfoliation and sonication of graphite, and functionalized graphene sheets with narrow size distribution were obtained. The polyglycerol-functionalized graphene sheets exhibited highly efficient cellular uptake and photothermal conversion, enabling it to serve as a photothermal agent for cancer therapy.

Application of selected advanced technologies to high performance, single-engine, business airplanes

NASA Technical Reports Server (NTRS)

Domack, C. S.; Martin, G. L.

1984-01-01

Improvements in performance and fuel efficiency are evaluated for five new configurations of a six place, single turboprop, business airplane derived from a conventional, aluminum construction baseline aircraft. Results show the greatest performance gains for enhancements in natural laminar flow. A conceptual diesel engine provides greater fuel efficiency but reduced performance. Less significant effects are produced by the utilization of composite materials construction or by reconfiguration from tractor to pusher propeller installation.

Characterization of the fast electrons distribution produced in a high intensity laser target interaction

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

Westover, B.; Lawrence Livermore National Laboratory, Livermore, California 94550; Chen, C. D.

2014-03-15

Experiments on the Titan laser (∼150 J, 0.7 ps, 2 × 10{sup 20} W cm{sup −2}) at the Lawrence Livermore National Laboratory were carried out in order to study the properties of fast electrons produced by high-intensity, short pulse laser interacting with matter under conditions relevant to Fast Ignition. Bremsstrahlung x-rays produced by these fast electrons were measured by a set of compact filter-stack based x-ray detectors placed at three angles with respect to the target. The measured bremsstrahlung signal allows a characterization of the fast electron beam spectrum, conversion efficiency of laser energy into fast electron kinetic energy and angular distribution. A Monte Carlo codemore » Integrated Tiger Series was used to model the bremsstrahlung signal and infer a laser to fast electron conversion efficiency of 30%, an electron slope temperature of about 2.2 MeV, and a mean divergence angle of 39°. Simulations were also performed with the hybrid transport code ZUMA which includes fields in the target. In this case, a conversion efficiency of laser energy to fast electron energy of 34% and a slope temperature between 1.5 MeV and 4 MeV depending on the angle between the target normal direction and the measuring spectrometer are found. The observed temperature of the bremsstrahlung spectrum, and therefore the inferred electron spectrum are found to be angle dependent.« less

A facile approach to manufacturing non-ionic surfactant nanodipsersions using proniosome technology and high-pressure homogenization.

PubMed

Najlah, Mohammad; Hidayat, Kanar; Omer, Huner K; Mwesigwa, Enosh; Ahmed, Waqar; AlObaidy, Kais G; Phoenix, David A; Elhissi, Abdelbary

2015-03-01

In this study, a niosome nanodispersion was manufactured using high-pressure homogenization following the hydration of proniosomes. Using beclometasone dipropionate (BDP) as a model drug, the characteristics of the homogenized niosomes were compared with vesicles prepared via the conventional approach of probe-sonication. Particle size, zeta potential, and the drug entrapment efficiency were similar for both size reduction mechanisms. However, high-pressure homogenization was much more efficient than sonication in terms of homogenization output rate, avoidance of sample contamination, offering a greater potential for a large-scale manufacturing of noisome nanodispersions. For example, high-pressure homogenization was capable of producing small size niosomes (209 nm) using a short single-step of size reduction (6 min) as compared with the time-consuming process of sonication (237 nm in >18 min) and the BDP entrapment efficiency was 29.65% ± 4.04 and 36.4% ± 2.8. In addition, for homogenization, the output rate of the high-pressure homogenization was 10 ml/min compared with 0.83 ml/min using the sonication protocol. In conclusion, a facile, applicable, and highly efficient approach for preparing niosome nanodispersions has been established using proniosome technology and high-pressure homogenization.

Hepatic mitochondrial energetics during catch-up fat with high-fat diets rich in lard or safflower oil.

PubMed

Crescenzo, Raffaella; Bianco, Francesca; Falcone, Italia; Tsalouhidou, Sofia; Yepuri, Gayathri; Mougios, Vassilis; Dulloo, Abdul G; Liverini, Giovanna; Iossa, Susanna

2012-09-01

We have investigated whether altered hepatic mitochondrial energetics could explain the differential effects of high-fat diets with low or high ω6 polyunsaturated fatty acid content (lard vs. safflower oil) on the efficiency of body fat recovery (catch-up fat) during refeeding after caloric restriction. After 2 weeks of caloric restriction, rats were isocalorically refed with a low-fat diet (LF) or high-fat diets made from either lard or safflower oil for 1 week, and energy balance and body composition changes were assessed. Hepatic mitochondrial energetics were determined from measurements of liver mitochondrial mass, respiratory capacities, and proton leak. Compared to rats refed the LF, the groups refed high-fat diets showed lower energy expenditure and increased efficiency of fat gain; these differences were less marked with high-safflower oil than with high-lard diet. The increase in efficiency of catch-up fat by the high-fat diets could not be attributed to differences in liver mitochondrial activity. By contrast, the lower fat gain with high-safflower oil than with high-lard diet is accompanied by higher mitochondrial proton leak and increased proportion of arachidonic acid in mitochondrial membranes. In conclusion, the higher efficiency for catch-up fat on high-lard diet than on LF cannot be explained by altered hepatic mitochondrial energetics. By contrast, the ability of the high-safflower oil diet to produce a less pronounced increase in the efficiency of catch-up fat may partly reside in increased incorporation of arachidonic acid in hepatic mitochondrial membranes, leading to enhanced proton leak and mitochondrial uncoupling.

A simple electroelution method for rapid protein purification: isolation and antibody production of alpha toxin from Clostridium septicum.

PubMed

Vázquez-Iglesias, Lorena; Estefanell-Ucha, Borja; Barcia-Castro, Leticia; Páez de la Cadena, María; Álvarez-Chaver, Paula; Ayude-Vázquez, Daniel; Rodríguez-Berrocal, Francisco Javier

2017-01-01

Clostridium septicum produces a number of diseases in human and farm animals which, in most of the cases, are fatal without clinical intervention. Alpha toxin is an important agent and the unique lethal virulent factor produced by Clostridium septicum. This toxin is haemolytic, highly lethal and necrotizing activities but is being used as an antigen to develop animal vaccines. The aim of this study was to isolate the alpha toxin of Clostridium septicum and produce highly specific antibodies against it. In this work, we have developed a simple and efficient method for alpha toxin purification, based on electroelution that can be used as a time-saving method for purifying proteins. This technique avoids contamination by other proteins that could appear during other protein purification techniques such chromatography. The highly purified toxin was used to produce polyclonal antibodies. The specificity of the antibodies was tested by western blot and these antibodies can be applied to the quantitative determination of alpha toxin by slot blot.

A simple electroelution method for rapid protein purification: isolation and antibody production of alpha toxin from Clostridium septicum

PubMed Central

Estefanell-Ucha, Borja; Barcia-Castro, Leticia; Páez de la Cadena, María; Álvarez-Chaver, Paula; Ayude-Vázquez, Daniel; Rodríguez-Berrocal, Francisco Javier

2017-01-01

Clostridium septicum produces a number of diseases in human and farm animals which, in most of the cases, are fatal without clinical intervention. Alpha toxin is an important agent and the unique lethal virulent factor produced by Clostridium septicum. This toxin is haemolytic, highly lethal and necrotizing activities but is being used as an antigen to develop animal vaccines. The aim of this study was to isolate the alpha toxin of Clostridium septicum and produce highly specific antibodies against it. In this work, we have developed a simple and efficient method for alpha toxin purification, based on electroelution that can be used as a time-saving method for purifying proteins. This technique avoids contamination by other proteins that could appear during other protein purification techniques such chromatography. The highly purified toxin was used to produce polyclonal antibodies. The specificity of the antibodies was tested by western blot and these antibodies can be applied to the quantitative determination of alpha toxin by slot blot. PMID:28652930

Phase plate technology for laser marking of magnetic discs

DOEpatents

Neuman, B.; Honig, J.; Hackel, L.; Dane, C.B.; Dixit, S.

1998-10-27

An advanced design for a phase plate enables the distribution of spots in arbitrarily shaped patterns with very high uniformity and with a continuously or near-continuously varying phase pattern. A continuous phase pattern eliminates large phase jumps typically expected in a grating that provides arbitrary shapes. Large phase jumps increase scattered light outside of the desired pattern, reduce efficiency and can make the grating difficult to manufacture. When manufacturing capabilities preclude producing a fully continuous grating, the present design can be easily adapted to minimize manufacturing errors and maintain high efficiencies. This continuous grating is significantly more efficient than previously described Dammann gratings, offers much more flexibility in generating spot patterns and is easier to manufacture and replicate than a multi-level phase grating. 3 figs.

Combustion synthesis of ceramic-metal composite materials in microgravity

NASA Technical Reports Server (NTRS)

Moore, John

1995-01-01

Combustion synthesis, self-propagating high temperature synthesis (SHS) or reactive synthesis provides an attractive alternative to conventional methods of producing advanced materials since this technology is based on the ability of highly exothermic reactions to be self sustaining and, therefore, energetically efficient. The exothermic SHS reaction is initiated at the ignition temperature, T(sub ig), and generates heat which is manifested in a maximum or combustion temperature, T(sub c), which can exceed 3000 K . Such high combustion temperatures are capable of melting and/or volatilizing reactant and product species and, therefore, present an opportunity for producing structure and property modification and control through liquid-solid, vapor-liquid-solid, and vapor-solid transformations.

An Improved System for Generation of Diploid Cloned Porcine Embryos Using Induced Pluripotent Stem Cells Synchronized to Metaphase.

PubMed

Kim, Eunhye; Zheng, Zhong; Jeon, Yubyeol; Jin, Yong-Xun; Hwang, Seon-Ung; Cai, Lian; Lee, Chang-Kyu; Kim, Nam-Hyung; Hyun, Sang-Hwan

2016-01-01

Pigs provide outstanding models of human genetic diseases due to their striking similarities with human anatomy, physiology and genetics. Although transgenic pigs have been produced using genetically modified somatic cells and nuclear transfer (SCNT), the cloning efficiency was extremely low. Here, we report an improved method to produce diploid cloned embryos from porcine induced pluripotent stem cells (piPSCs), which were synchronized to the G2/M stage using a double blocking method with aphidicolin and nocodazole. The efficiency of this synchronization method on our piPSC lines was first tested. Then, we modified our traditional SCNT protocol to find a workable protocol. In particular, the removal of a 6DMAP treatment post-activation enhanced the extrusion rate of pseudo-second-polar bodies (p2PB) (81.3% vs. 15.8%, based on peak time, 4hpa). Moreover, an immediate activation method yielded significantly more blastocysts than delayed activation (31.3% vs. 16.0%, based on fused embryos). The immunofluorescent results confirmed the effect of the 6DMAP treatment removal, showing remarkable p2PB extrusion during a series of nuclear transfer procedures. The reconstructed embryos from metaphase piPSCs with our modified protocol demonstrated normal morphology at 2-cell, 4-cell and blastocyst stages and a high rate of normal karyotype. This study demonstrated a new and efficient way to produce viable cloned embryos from piPSCs when synchronized to the G2/M phase of the cell cycle, which may lead to opportunities to produce cloned pigs from piPSCs more efficiently.

Efficient transformation of sucrose into high pullulan concentrations by Aureobasidium melanogenum TN1-2 isolated from a natural honey.

PubMed

Jiang, Hong; Xue, Si-Jia; Li, Yan-Feng; Liu, Guang-Lei; Chi, Zhen-Ming; Hu, Zhong; Chi, Zhe

2018-08-15

A very high pullulan producing yeast-like fungus, Aureobasidium melanogenum TN1-2 isolated from a natural honey was found to be able to produce 97.0 g/L of pullulan from 140.0 g/L sucrose at a flask level while it could yield 114.0 g/L of pullulan within 134 h during a 10-liter fermentation, the yield was 0.81 g/g and the productivity was 0.86 g/L/h. The high ability to biosynthesize pullulan by this yeast-like fungal strain TN1-2 was related to high glucosyltransferase activity, high phosphofructo-2-kinase activity, high content of its cellular glycerol and low glucose repressor. The Mw of the produced pullulan was 1.42 × 10 5  g/mol. The low Mw may be due to the high α-amylase, glucoamylase and isopullulanase activities. The intracellular level of trehalose had no influence on high pullulan production by the yeast-like fungal strain TN1-2. Copyright © 2018. Published by Elsevier Ltd.

RNAi Knock-Down of LHCBM1, 2 and 3 Increases Photosynthetic H2 Production Efficiency of the Green Alga Chlamydomonas reinhardtii

PubMed Central

Oey, Melanie; Ross, Ian L.; Stephens, Evan; Steinbeck, Janina; Wolf, Juliane; Radzun, Khairul Adzfa; Kügler, Johannes; Ringsmuth, Andrew K.; Kruse, Olaf; Hankamer, Ben

2013-01-01

Single cell green algae (microalgae) are rapidly emerging as a platform for the production of sustainable fuels. Solar-driven H2 production from H2O theoretically provides the highest-efficiency route to fuel production in microalgae. This is because the H2-producing hydrogenase (HYDA) is directly coupled to the photosynthetic electron transport chain, thereby eliminating downstream energetic losses associated with the synthesis of carbohydrate and oils (feedstocks for methane, ethanol and oil-based fuels). Here we report the simultaneous knock-down of three light-harvesting complex proteins (LHCMB1, 2 and 3) in the high H2-producing Chlamydomonas reinhardtii mutant Stm6Glc4 using an RNAi triple knock-down strategy. The resultant Stm6Glc4L01 mutant exhibited a light green phenotype, reduced expression of LHCBM1 (20.6% ±0.27%), LHCBM2 (81.2% ±0.037%) and LHCBM3 (41.4% ±0.05%) compared to 100% control levels, and improved light to H2 (180%) and biomass (165%) conversion efficiencies. The improved H2 production efficiency was achieved at increased solar flux densities (450 instead of ∼100 µE m−2 s−1) and high cell densities which are best suited for microalgae production as light is ideally the limiting factor. Our data suggests that the overall improved photon-to-H2 conversion efficiency is due to: 1) reduced loss of absorbed energy by non-photochemical quenching (fluorescence and heat losses) near the photobioreactor surface; 2) improved light distribution in the reactor; 3) reduced photoinhibition; 4) early onset of HYDA expression and 5) reduction of O2-induced inhibition of HYDA. The Stm6Glc4L01 phenotype therefore provides important insights for the development of high-efficiency photobiological H2 production systems. PMID:23613840

Self-bunching electron guns

NASA Astrophysics Data System (ADS)

Mako, Frederick M.; Len, L. K.

1999-05-01

We report on three electron gun projects that are aimed at power tube and injector applications. The purpose of the work is to develop robust electron guns which produce self-bunched, high-current-density beams. We have demonstrated, in a microwave cavity, self-bunching, cold electron emission, long life, and tolerance to contamination. The cold process is based on secondary electron emission. FMT has studied using simulation codes the resonant bunching process which gives rise to high current densities (0.01-5 kA/cm2), high charge bunches (up to 500 nC/bunch), and short pulses (1-100 ps) for frequencies from 1 to 12 GHz. The beam pulse width is nominally ˜5% of the rf period. The first project is the L-Band Micro-Pulse Gun (MPG). Measurements show ˜40 ps long micro-bunches at ˜20 A/cm2 without contamination due to air exposure. Lifetime testing has been carried out for about 18 months operating at 1.25 GHz for almost 24 hours per day at a repetition rate of 300 Hz and 5 μs-long macro-pulses. Approximately 5.8×1013 micro-bunches or 62,000 coulombs have passed through this gun and it is still working fine. The second project, the S-Band MPG, is now operational. It is functioning at a frequency of 2.85 GHz, a repetition rate of 30 Hz, with a 2 μs-long macro-pulse. It produces about 45 A in the macro-pulse. The third project is a 34.2 GHz frequency-multiplied source driven by an X-Band MPG. A point design was performed at an rf output power of 150 MW at 34.2 GHz. The resulting system efficiency is 53% and the gain is 60 dB. The system efficiency includes the input cavity efficiency, input driver efficiency (a 50 MW klystron at 11.4 GHz), output cavity efficiency, and the post-acceleration efficiency.

UV activation of polymeric high aspect ratio microstructures: ramifications in antibody surface loading for circulating tumor cell selection.

PubMed

Jackson, Joshua M; Witek, Małgorzata A; Hupert, Mateusz L; Brady, Charles; Pullagurla, Swathi; Kamande, Joyce; Aufforth, Rachel D; Tignanelli, Christopher J; Torphy, Robert J; Yeh, Jen Jen; Soper, Steven A

2014-01-07

The need to activate thermoplastic surfaces using robust and efficient methods has been driven by the fact that replication techniques can be used to produce microfluidic devices in a high production mode and at low cost, making polymer microfluidics invaluable for in vitro diagnostics, such as circulating tumor cell (CTC) analysis, where device disposability is critical to mitigate artifacts associated with sample carryover. Modifying the surface chemistry of thermoplastic devices through activation techniques can be used to increase the wettability of the surface or to produce functional scaffolds to allow for the covalent attachment of biologics, such as antibodies for CTC recognition. Extensive surface characterization tools were used to investigate UV activation of various surfaces to produce uniform and high surface coverage of functional groups, such as carboxylic acids in microchannels of different aspect ratios. We found that the efficiency of the UV activation process is highly dependent on the microchannel aspect ratio and the identity of the thermoplastic substrate. Colorimetric assays and fluorescence imaging of UV-activated microchannels following EDC/NHS coupling of Cy3-labeled oligonucleotides indicated that UV-activation of a PMMA microchannel with an aspect ratio of ~3 was significantly less efficient toward the bottom of the channel compared to the upper sections. This effect was a consequence of the bulk polymer's damping of the modifying UV radiation due to absorption artifacts. In contrast, this effect was less pronounced for COC. Moreover, we observed that after thermal fusion bonding of the device's cover plate to the substrate, many of the generated functional groups buried into the bulk rendering them inaccessible. The propensity of this surface reorganization was found to be higher for PMMA compared to COC. As an example of the effects of material and microchannel aspect ratios on device functionality, thermoplastic devices for the selection of CTCs from whole blood were evaluated, which required the immobilization of monoclonal antibodies to channel walls. From our results, we concluded the CTC yield and purity of isolated CTCs were dependent on the substrate material with COC producing the highest clinical yields for CTCs as well as better purities compared to PMMA.

Exploration of graphene oxide as an intelligent platform for cancer vaccines

NASA Astrophysics Data System (ADS)

Yue, Hua; Wei, Wei; Gu, Zonglin; Ni, Dezhi; Luo, Nana; Yang, Zaixing; Zhao, Lin; Garate, Jose Antonio; Zhou, Ruhong; Su, Zhiguo; Ma, Guanghui

2015-11-01

We explored an intelligent vaccine system via facile approaches using both experimental and theoretical techniques based on the two-dimensional graphene oxide (GO). Without extra addition of bio/chemical stimulators, the microsized GO imparted various immune activation tactics to improve the antigen immunogenicity. A high antigen adsorption was acquired, and the mechanism was revealed to be a combination of electrostatic, hydrophobic, and π-π stacking interactions. The ``folding GO'' acted as a cytokine self-producer and antigen reservoir and showed a particular autophagy, which efficiently promoted the activation of antigen presenting cells (APCs) and subsequent antigen cross-presentation. Such a ``One but All'' modality thus induced a high level of anti-tumor responses in a programmable way and resulted in efficient tumor regression in vivo. This work may shed light on the potential use of a new dimensional nano-platform in the development of high-performance cancer vaccines.We explored an intelligent vaccine system via facile approaches using both experimental and theoretical techniques based on the two-dimensional graphene oxide (GO). Without extra addition of bio/chemical stimulators, the microsized GO imparted various immune activation tactics to improve the antigen immunogenicity. A high antigen adsorption was acquired, and the mechanism was revealed to be a combination of electrostatic, hydrophobic, and π-π stacking interactions. The ``folding GO'' acted as a cytokine self-producer and antigen reservoir and showed a particular autophagy, which efficiently promoted the activation of antigen presenting cells (APCs) and subsequent antigen cross-presentation. Such a ``One but All'' modality thus induced a high level of anti-tumor responses in a programmable way and resulted in efficient tumor regression in vivo. This work may shed light on the potential use of a new dimensional nano-platform in the development of high-performance cancer vaccines. Electronic supplementary information (ESI) available. See DOI: 10.1039/c5nr04986e

The design of a linear L-band high power amplifier for mobile communication satellites

NASA Technical Reports Server (NTRS)

Whittaker, N.; Brassard, G.; Li, E.; Goux, P.

1990-01-01

A linear L-band solid state high power amplifier designed for the space segment of the Mobile Satellite (MSAT) mobile communication system is described. The amplifier is capable of producing 35 watts of RF power with multitone signal at an efficiency of 25 percent and with intermodulation products better than 16 dB below carrier.

A Rapid Microwave-Assisted Thermolysis Route to Highly Crystalline Carbon Nitrides for Efficient Hydrogen Generation.

PubMed

Guo, Yufei; Li, Jing; Yuan, Yupeng; Li, Lu; Zhang, Mingyi; Zhou, Chenyan; Lin, Zhiqun

2016-11-14

Highly crystalline graphitic carbon nitride (g-C 3 N 4 ) with decreased structural imperfections benefits from the suppression of electron-hole recombination, which enhances its hydrogen generation activity. However, producing such g-C 3 N 4 materials by conventional heating in an electric furnace has proven challenging. Herein, we report on the synthesis of high-quality g-C 3 N 4 with reduced structural defects by judiciously combining the implementation of melamine-cyanuric acid (MCA) supramolecular aggregates and microwave-assisted thermolysis. The g-C 3 N 4 material produced after optimizing the microwave reaction time can effectively generate H 2 under visible-light irradiation. The highest H 2 evolution rate achieved was 40.5 μmol h -1 , which is two times higher than that of a g-C 3 N 4 sample prepared by thermal polycondensation of the same supramolecular aggregates in an electric furnace. The microwave-assisted thermolysis strategy is simple, rapid, and robust, thereby providing a promising route for the synthesis of high-efficiency g-C 3 N 4 photocatalysts. © 2016 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Technical evaluation of photobioreactors for microalgae cultivation

NASA Astrophysics Data System (ADS)

Płaczek, Małgorzata; Patyna, Agnieszka; Witczak, Stanisław

2017-10-01

This paper undertakes the description and assessment of various solutions applied for the design of photobioreactors as the type of apparatus, which can provide high output of green algae biomass. The design of such apparatus plays an important role in the context of the concurrent fulfillment of ecological and economic requirements, which are necessary to conduct an efficient and effective technology using cheap and easily accessible resources to produce different goods. Nowadays, algae is seen as one of the most promising sustainable way to produce energy in the future (biofuels, electricity, thermal energy) but technologies of biomass production and processing are still under development particularly to increase biomass and energy output. The cultivation costs in closed systems are still high, limiting their commercial applications to high-valued compounds but they can be reduced by efficient bioreactor designs, which are able to achieve high areal biomass productivities. This paper focuses on the advantages and drawbacks associated with the application of the particular types of bioreactors in algae production, description of their operation parameters and area for practical application, pointing of the constructions (tubular, flat panel, bubble column) that can contribute to improvement the profitability of large-scale production.

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

Chang, Amy T.Y., E-mail: changty@ha.org.hk; Hung, Albert W.M.; Cheung, Fion W.K.

Purpose: Intensity modulated radiation therapy (IMRT) is widely used to achieve a highly conformal dose and improve treatment outcome. However, plan quality and planning time are institute and planner dependent, and no standardized tool exists to recognize an optimal plan. RapidPlan, a knowledge-based algorithm, can generate constraints to assist optimization and produce high-quality IMRT plans. This report evaluated the quality and efficiency of using RapidPlan in nasopharyngeal carcinoma (NPC) IMRT planning. Methods and Materials: RapidPlan was configured using 79 radical IMRT plans for NPC; 20 consecutive NPC patients indicated for radical radiation therapy between October 2014 and May 2015 weremore » then recruited to assess its performance. The ability of RapidPlan to produce acceptable plans was evaluated. For plans that could not achieve clinical acceptance, manual touch-up was performed. The IMRT plans produced without RapidPlan (manual plans) and with RapidPlan (RP-2 plans, including those with manual touch-up) were compared in terms of dosimetric quality and planning efficiency. Results: RapidPlan by itself could produce clinically acceptable plans for 9 of the 20 patients; manual touch-up increased the number of acceptable plans (RP-2 plans) to 19. The target dose coverage and conformity were very similar. No difference was found in the maximum dose to the brainstem and optic chiasm. RP-2 plans delivered a higher maximum dose to the spinal cord (46.4 Gy vs 43.9 Gy, P=.002) but a lower dose to the parotid (mean dose to right parotid, 37.3 Gy vs 45.4 Gy; left, 34.4 Gy vs 43.1 Gy; P<.001) and the right cochlea (mean dose, 48.6 Gy vs 52.6 Gy; P=.02). The total planning time for RP-2 plans was significantly less than that for manual plans (64 minutes vs 295 minutes, P<.001). Conclusions: This study shows that RapidPlan can significantly improve planning efficiency and produce quality IMRT plans for NPC patients.« less

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

Junhua Jiang; Ted Aulich

An electrolytic renewable nitrogen fertilizer process that utilizes wind-generated electricity, N{sub 2} extracted from air, and syngas produced via the gasification of biomass to produce nitrogen fertilizer ammonia was developed at the University of North Dakota Energy & Environmental Research Center. This novel process provides an important way to directly utilize biosyngas generated mainly via the biomass gasification in place of the high-purity hydrogen which is required for Haber Bosch-based production of the fertilizer for the production of the widely used nitrogen fertilizers. Our preliminary economic projection shows that the economic competitiveness of the electrochemical nitrogen fertilizer process strongly dependsmore » upon the cost of hydrogen gas and the cost of electricity. It is therefore expected the cost of nitrogen fertilizer production could be considerably decreased owing to the direct use of cost-effective 'hydrogen-equivalent' biosyngas compared to the high-purity hydrogen. The technical feasibility of the electrolytic process has been proven via studying ammonia production using humidified carbon monoxide as the hydrogen-equivalent vs. the high-purity hydrogen. Process optimization efforts have been focused on the development of catalysts for ammonia formation, electrolytic membrane systems, and membrane-electrode assemblies. The status of the electrochemical ammonia process is characterized by a current efficiency of 43% using humidified carbon monoxide as a feedstock to the anode chamber and a current efficiency of 56% using high-purity hydrogen as the anode gas feedstock. Further optimization of the electrolytic process for higher current efficiency and decreased energy consumption is ongoing at the EERC.« less

Static Converter for High Energy Utilization, Modular, Small Nuclear Power Plants

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

El-Genk, Mohamed S.; Tournier, Jean-Michel P.

2002-07-01

This paper presents and analyzes the performance of high efficiency, high total energy utilization, static converters, which could be used in conjunction with small nuclear reactor plants in remote locations and in undersea applications, requiring little or no maintenance. The converters consist of a top cycle of Alkali Metal Thermal-to-Electric Conversion (AMTEC) units and PbTe thermoelectric (TE) bottom cycle. In addition to converting the reactor thermal power to electricity at 1150 K or less, at a thermodynamic efficiency in the low to mid thirties, the heat rejection from the TE bottom cycle could be used for space heating, industrial processing,more » or sea water desalination. The results indicated that for space heating applications, where the rejected thermal power from the TE bottom cycle is removed by natural convection of ambient air, a total utilization of the reactor thermal power of > 80% is possible. When operated at 1030 K, potassium AMTEC/TE converters are not only more efficient than the sodium AMTEC/TE converters but produce more electrical power. The present analysis showed that a single converter could be sized to produce up to 100 kWe and 70 kWe, for the Na-AMTEC/TE units when operating at 1150 K and the K-AMTEC/TE units when operating at 1030 K, respectively. Such modularity is an added advantage to the high-energy utilization of the present AMTEC/TE converters. (authors)« less

Over production of fermentable sugar for bioethanol production from carbohydrate-rich Malaysian food waste via sequential acid-enzymatic hydrolysis pretreatment.

PubMed

Hafid, Halimatun Saadiah; Nor 'Aini, Abdul Rahman; Mokhtar, Mohd Noriznan; Talib, Ahmad Tarmezee; Baharuddin, Azhari Samsu; Umi Kalsom, Md Shah

2017-09-01

In Malaysia, the amount of food waste produced is estimated at approximately 70% of total municipal solid waste generated and characterised by high amount of carbohydrate polymers such as starch, cellulose, and sugars. Considering the beneficial organic fraction contained, its utilization as an alternative substrate specifically for bioethanol production has receiving more attention. However, the sustainable production of bioethanol from food waste is linked to the efficient pretreatment needed for higher production of fermentable sugar prior to fermentation. In this work, a modified sequential acid-enzymatic hydrolysis process has been developed to produce high concentration of fermentable sugars; glucose, sucrose, fructose and maltose. The process started with hydrothermal and dilute acid pretreatment by hydrochloric acid (HCl) and sulphuric acid (H 2 SO 4 ) which aim to degrade larger molecules of polysaccharide before accessible for further steps of enzymatic hydrolysis by glucoamylase. A kinetic model is proposed to perform an optimal hydrolysis for obtaining high fermentable sugars. The results suggested that a significant increase in fermentable sugar production (2.04-folds) with conversion efficiency of 86.8% was observed via sequential acid-enzymatic pretreatment as compared to dilute acid pretreatment (∼42.4% conversion efficiency). The bioethanol production by Saccharomyces cerevisiae utilizing fermentable sugar obtained shows ethanol yield of 0.42g/g with conversion efficiency of 85.38% based on the theoretical yield was achieved. The finding indicates that food waste can be considered as a promising substrate for bioethanol production. Copyright © 2017. Published by Elsevier Ltd.

Efficiency in hydrocarbon degradation and biosurfactant production by Joostella sp. A8 when grown in pure culture and consortia.

PubMed

Rizzo, Carmen; Rappazzo, Alessandro Ciro; Michaud, Luigi; De Domenico, Emilio; Rochera, Carlos; Camacho, Antonio; Lo Giudice, Angelina

2018-05-01

Joostella strains are emerging candidates for biosurfactant production. Here such ability was analyzed for Joostella strain A8 in comparison with Alcanivorax strain A53 and Pseudomonas strain A6, all previously isolated from hydrocarbon enrichment cultures made of polychaete homogenates. In pure cultures Joostella sp. A8 showed the highest stable emulsion percentage (78.33%), hydrophobicity rate (62.67%), and an optimal surface tension reduction during growth in mineral medium supplemented with diesel oil (reduction of about 12mN/m), thus proving to be highly competitive with Alcanivorax and Pseudomonas strains. During growth in pure culture different level of biodegradation were detected for Alcanivorax strain A53 (52.7%), Pseudomonas strain A6 (38.2%) and Joostella strain A8 (26.8%). When growing in consortia, isolates achieved similar abundance values, with the best efficiency that was observed for the Joostella-Pseudomonas co-culture. Gas-chromatographic analysis revealed an increase in the biodegradation efficiency in co-cultures (about 90%), suggesting that the contemporary action of different bacterial species could improve the process. Results were useful to compare the efficiencies of well-known biosurfactant producers (i.e. Pseudomonas and Alcanivorax representatives) with a still unknown biosurfactant producer, i.e. Joostella, and to confirm them as optimal biosurfactant-producing candidates. Copyright © 2017. Published by Elsevier B.V.

Highly efficient production of hyaluronic acid by Streptococcus zooepidemicus R42 derived from heterologous expression of bacterial haemoglobin and mutant selection.

PubMed

Lu, J F; Zhu, Y; Sun, H L; Liang, S; Leng, F F; Li, H Y

2016-04-01

During Streptococcus zooepidemicus fermentation, most carbon sources are used to synthesize lactic acid, which can inhibit strain growth and hyaluronic acid production. Here, we expressed bacterial haemoglobin (Vhb) in Strep. zooepidemicus. Due to highly efficient oxygen use, only 15·26 g l(-1) lactic acid was produced, which is 0·73 times the quantity produced by the control strain. Compared with the control strain (1·61 g l(-1) ), hyaluronic acid (HA) production in this strain did not substantially increase, only to 2·16 g l(-1) . Next, we used a series of N-methyl-N'-nitro-N-nitroso-guanidine (NTG) treatments and selection programmes. Finally, we generated a hyaluronidase-negative and rifampin-resistant mutant strain that produces high levels of HA. The optimum carbon concentration for maximum hyaluronic acid production is only 30 g l(-1) of sucrose, which is lower than the control strain (60 g l(-1) ). The oxygen transfer rate coefficient KL a increased significantly to 372 ± 53 h(-1) from 18 ± 4 h(-1) of the control. The optimum carbon source for this strain is 21 g l(-1) of sucrose, 9 g l(-1) of maltose and 5 g l(-1) of glutamic acid. Hyaluronic acid accumulated at 6·7 g l(-1) in the culture broth. However, the molecular weight of HA decreased from 1835 KDa (Control) to 429 kDa. The prepared low-molecular weight HA could function as potential antiangiogenic substances, antiviral and antitumour agents to possibly be used as functional food ingredients. Hyaluronic acid (HA) has been used for a wide range of applications in health, cosmetic and clinical fields. During fermentation of Streptococcus to produce HA, 80-85% of the carbon source is used to produce lactic acid and acetic acid, and only approx. 5 and 10% of the carbon source is used to produce HA and biomass respectively. Here, we expressed bacteria haemoglobin (Vhb) in Streptococcus zooepidemicus, which can dramatically inhibit lactic acid production. After NTG treatments and selection programmes, we identified a mutant strain with highly efficient hyaluronic acid production (6·7 g l(-1) ) under economic fermentation conditions. © 2016 The Society for Applied Microbiology.

Engineered heat treated methanogenic granules: a promising biotechnological approach for extreme thermophilic biohydrogen production.

PubMed

Abreu, Angela A; Alves, Joana I; Pereira, M Alcina; Karakashev, Dimitar; Alves, M Madalena; Angelidaki, Irini

2010-12-01

In the present study, two granular systems were compared in terms of hydrogen production rate, stability and bacterial diversity under extreme thermophilic conditions (70 degrees C). Two EGSB reactors were individually inoculated with heat treated methanogenic granules (HTG) and HTG amended with enrichment culture with high capacity of hydrogen production (engineered heat treated methanogenic granules - EHTG), respectively. The reactor inoculated with EHTG (R(EHTG)) attained a maximum production rate of 2.7l H(2)l(-1)day(-1) in steady state. In comparison, the R(HTG) containing the HTG granules was very unstable, with low hydrogen productions and only two peaks of hydrogen (0.8 and 1.5l H(2)l(-1)day(-1)). The presence of active hydrogen producers in the R(EHTG) system during the reactor start-up resulted in the development of an efficient H(2)-producing bacterial community. The results showed that "engineered inocula" where known hydrogen producers are co-inoculated with HTG is an efficient way to start up biohydrogen-producing reactors. Copyright (c) 2010 Elsevier Ltd. All rights reserved.

Expression of naturally ionic liquid-tolerant thermophilic cellulases in Aspergillus niger

DOE PAGES

Amaike Campen, Saori; Lynn, Jed; Sibert, Stephanie J.; ...

2017-12-27

Efficient deconstruction of plant biomass is a major barrier to the development of viable lignocellulosic biofuels. Pretreatment with ionic liquids reduces lignocellulose recalcitrance to enzymatic hydrolysis, increasing yields of sugars for conversion into biofuels. However, commercial cellulases are not compatible with many ionic liquids, necessitating extensive water washing of pretreated biomass prior to hydrolysis. To circumvent this issue, previous research has demonstrated that several thermophilic bacterial cellulases can efficiently deconstruct lignocellulose in the presence of the ionic liquid, 1-ethyl-3-methylimadizolium acetate. As promising as these enzymes are, they would need to be produced at high titer in an industrial enzyme productionmore » host before they could be considered a viable alternative to current commercial cellulases. Aspergillus Niger has been used to produce high titers of secreted enzymes in industry and therefore, we assessed the potential of this organism to be used as an expression host for these ionic liquid-tolerant cellulases. We demonstrated that 29 of these cellulases were expressed at detectable levels in a wild-type strain of A. Niger, indicating a basic level of compatibility and potential to be produced at high levels in a host engineered to produce high titers of enzymes. We then profiled one of these enzymes in detail, the β-glucosidase A5IL97, and compared versions expressed in both A. Niger and Escherichia coli. Finally, this comparison revealed the enzymatic activity of A5IL97 purified from E. coli and A. Niger is equivalent, suggesting that A. Niger could be an excellent enzyme production host for enzymes originally characterized in E. coli, facilitating the transition from the laboratory to industry.« less

Expression of naturally ionic liquid-tolerant thermophilic cellulases in Aspergillus niger

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

Amaike Campen, Saori; Lynn, Jed; Sibert, Stephanie J.

Efficient deconstruction of plant biomass is a major barrier to the development of viable lignocellulosic biofuels. Pretreatment with ionic liquids reduces lignocellulose recalcitrance to enzymatic hydrolysis, increasing yields of sugars for conversion into biofuels. However, commercial cellulases are not compatible with many ionic liquids, necessitating extensive water washing of pretreated biomass prior to hydrolysis. To circumvent this issue, previous research has demonstrated that several thermophilic bacterial cellulases can efficiently deconstruct lignocellulose in the presence of the ionic liquid, 1-ethyl-3-methylimadizolium acetate. As promising as these enzymes are, they would need to be produced at high titer in an industrial enzyme productionmore » host before they could be considered a viable alternative to current commercial cellulases. Aspergillus Niger has been used to produce high titers of secreted enzymes in industry and therefore, we assessed the potential of this organism to be used as an expression host for these ionic liquid-tolerant cellulases. We demonstrated that 29 of these cellulases were expressed at detectable levels in a wild-type strain of A. Niger, indicating a basic level of compatibility and potential to be produced at high levels in a host engineered to produce high titers of enzymes. We then profiled one of these enzymes in detail, the β-glucosidase A5IL97, and compared versions expressed in both A. Niger and Escherichia coli. Finally, this comparison revealed the enzymatic activity of A5IL97 purified from E. coli and A. Niger is equivalent, suggesting that A. Niger could be an excellent enzyme production host for enzymes originally characterized in E. coli, facilitating the transition from the laboratory to industry.« less

Expression of naturally ionic liquid-tolerant thermophilic cellulases in Aspergillus niger

PubMed Central

Lynn, Jed; Sibert, Stephanie J.; Srikrishnan, Sneha; Phatale, Pallavi; Feldman, Taya; Guenther, Joel M.; Hiras, Jennifer; Tran, Yvette Thuy An; Singer, Steven W.; Adams, Paul D.; Sale, Kenneth L.; Simmons, Blake A.; Baker, Scott E.; Magnuson, Jon K.; Gladden, John M.

2017-01-01

Efficient deconstruction of plant biomass is a major barrier to the development of viable lignocellulosic biofuels. Pretreatment with ionic liquids reduces lignocellulose recalcitrance to enzymatic hydrolysis, increasing yields of sugars for conversion into biofuels. However, commercial cellulases are not compatible with many ionic liquids, necessitating extensive water washing of pretreated biomass prior to hydrolysis. To circumvent this issue, previous research has demonstrated that several thermophilic bacterial cellulases can efficiently deconstruct lignocellulose in the presence of the ionic liquid, 1-ethyl-3-methylimadizolium acetate. As promising as these enzymes are, they would need to be produced at high titer in an industrial enzyme production host before they could be considered a viable alternative to current commercial cellulases. Aspergillus niger has been used to produce high titers of secreted enzymes in industry and therefore, we assessed the potential of this organism to be used as an expression host for these ionic liquid-tolerant cellulases. We demonstrated that 29 of these cellulases were expressed at detectable levels in a wild-type strain of A. niger, indicating a basic level of compatibility and potential to be produced at high levels in a host engineered to produce high titers of enzymes. We then profiled one of these enzymes in detail, the β-glucosidase A5IL97, and compared versions expressed in both A. niger and Escherichia coli. This comparison revealed the enzymatic activity of A5IL97 purified from E. coli and A. niger is equivalent, suggesting that A. niger could be an excellent enzyme production host for enzymes originally characterized in E. coli, facilitating the transition from the laboratory to industry. PMID:29281693

Expression of naturally ionic liquid-tolerant thermophilic cellulases in Aspergillus niger.

PubMed

Amaike Campen, Saori; Lynn, Jed; Sibert, Stephanie J; Srikrishnan, Sneha; Phatale, Pallavi; Feldman, Taya; Guenther, Joel M; Hiras, Jennifer; Tran, Yvette Thuy An; Singer, Steven W; Adams, Paul D; Sale, Kenneth L; Simmons, Blake A; Baker, Scott E; Magnuson, Jon K; Gladden, John M

2017-01-01

Efficient deconstruction of plant biomass is a major barrier to the development of viable lignocellulosic biofuels. Pretreatment with ionic liquids reduces lignocellulose recalcitrance to enzymatic hydrolysis, increasing yields of sugars for conversion into biofuels. However, commercial cellulases are not compatible with many ionic liquids, necessitating extensive water washing of pretreated biomass prior to hydrolysis. To circumvent this issue, previous research has demonstrated that several thermophilic bacterial cellulases can efficiently deconstruct lignocellulose in the presence of the ionic liquid, 1-ethyl-3-methylimadizolium acetate. As promising as these enzymes are, they would need to be produced at high titer in an industrial enzyme production host before they could be considered a viable alternative to current commercial cellulases. Aspergillus niger has been used to produce high titers of secreted enzymes in industry and therefore, we assessed the potential of this organism to be used as an expression host for these ionic liquid-tolerant cellulases. We demonstrated that 29 of these cellulases were expressed at detectable levels in a wild-type strain of A. niger, indicating a basic level of compatibility and potential to be produced at high levels in a host engineered to produce high titers of enzymes. We then profiled one of these enzymes in detail, the β-glucosidase A5IL97, and compared versions expressed in both A. niger and Escherichia coli. This comparison revealed the enzymatic activity of A5IL97 purified from E. coli and A. niger is equivalent, suggesting that A. niger could be an excellent enzyme production host for enzymes originally characterized in E. coli, facilitating the transition from the laboratory to industry.

Transient transfection of serum-free suspension HEK 293 cell culture for efficient production of human rFVIII.

PubMed

Swiech, Kamilla; Kamen, Amine; Ansorge, Sven; Durocher, Yves; Picanço-Castro, Virgínia; Russo-Carbolante, Elisa M S; Neto, Mário S A; Covas, Dimas T

2011-11-24

Hemophilia A is a bleeding disorder caused by deficiency in coagulation factor VIII. Recombinant factor VIII (rFVIII) is an alternative to plasma-derived FVIII for the treatment of hemophilia A. However, commercial manufacturing of rFVIII products is inefficient and costly and is associated to high prices and product shortage, even in economically privileged countries. This situation may be solved by adopting more efficient production methods. Here, we evaluated the potential of transient transfection in producing rFVIII in serum-free suspension HEK 293 cell cultures and investigated the effects of different DNA concentration (0.4, 0.6 and 0.8 μg/106 cells) and repeated transfections done at 34° and 37 °C. We observed a decrease in cell growth when high DNA concentrations were used, but no significant differences in transfection efficiency and in the biological activity of the rFVIII were noticed. The best condition for rFVIII production was obtained with repeated transfections at 34 °C using 0.4 μg DNA/106 cells through which almost 50 IU of active rFVIII was produced six days post-transfection. Serum-free suspension transient transfection is thus a viable option for high-yield-rFVIII production. Work is in progress to further optimize the process and validate its scalability.

TRANSVERSE MODE ELECTRO-OPTIC MATERIALS.

DTIC Science & Technology

electro - optic modulators presently used are crystals such as KDP which exhibit a longitudinal electro - optic effect. It has been demonstrated that a more efficient modulator can be produced when a crystal having a transverse electro - optic effect is employed. Generally these crystals are produced either from the melt or from fluxes. Since melt grown crystals must be cooled through several hundred degrees and often must undergo phase transitions, these crystals are generally highly strained. Flux grown crystals are also

Analytical applications of MIPs in diagnostic assays: future perspectives.

PubMed

Bedwell, Thomas S; Whitcombe, Michael J

2016-03-01

Many efforts have been made to produce artificial materials with biomimetic properties for applications in binding assays. Among these efforts, the technique of molecular imprinting has received much attention because of the high selectivity obtainable for molecules of interest, robustness of the produced polymers, simple and short synthesis, and excellent cost efficiency. In this review, progress in the field of molecularly imprinted sorbent assays is discussed-with a focus on work conducted from 2005 to date.

Performance of dithiocarbamate-type flocculant in treating simulated polymer flooding produced water.

PubMed

Gao, Baoyu; Jia, Yuyan; Zhang, Yongqiang; Li, Qian; Yue, Qinyan

2011-01-01

Produced water from polymer flooding is difficult to treat due to its high polymer concentration, high viscosity, and emulsified characteristics. The dithiocarbamate flocculant, DTC (T403), was prepared by the amine-terminated polyoxypropane-ether compound known as Jeffamine-T403. The product was characterized by IR spectra and elemental analysis. The DTC agent chelating with Fe2+ produced a network polymer matrix, which captured and removed oil droplets efficiently. Oil removal by the flocculent on simulated produced water with 0, 200, 500, 900 mg/L of partially hydrolyzed polyacrylamide (HPAM) was investigated for aspects of effectiveness of DTC (T403) dosage and concentrations of HPAM and Fe2+ ions in the wastewater. Results showed that HPAM had a negative influence on oil removal efficiency when DTC (T403) dosage was lower than 20 mg/L. However, residual oil concentrations in tested samples with different concentrations of HPAM all decreased below 10 mg/L when DTC (T403) dosage reached 30 mg/L. The concentration of Fe2+ in the initial wastewater had a slight effect on oil removal at the range of 2-12 mg/L. Results showed that Fe3+ could not be used in place of Fe2+ as Fe3+ could not react with DTC under flocculated conditions. The effects of mineral salts ions were also investigated.

Ceramic High Efficiency Particulate Air (HEPA) Filter Final Report CRADA No. TC02160.0

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

Mitchell, M.; Bergman, W.

2017-08-25

The technical objective of this project was to develop a ceramic HEPA filter technology, by initially producing and testing coupon ceramics, small scale prototypes, and full scale prototype HEPA filters, and to address relevant manufacturing and commercialization technical issues.

Are We Good at Detecting Conflict during Reasoning?

ERIC Educational Resources Information Center

Pennycook, Gordon; Fugelsang, Jonathan A.; Koehler, Derek J.

2012-01-01

Recent evidence suggests that people are highly efficient at detecting conflicting outputs produced by competing intuitive and analytic reasoning processes. Specifically, De Neys and Glumicic (2008) demonstrated that participants reason longer about problems that are characterized by conflict (as opposed to agreement) between stereotypical…

High forage quality helps maintain resilience to gastrointestinal parasites on sheep and goats

USDA-ARS?s Scientific Manuscript database

Control of gastrointestinal (GI) parasites (especially the blood feeder Haemonchus contortus) in small ruminants is a problem for sheep and goat producers. Gastrointestinal parasite overloads reduce livestock performance and production efficiency, and can result in increased death losses of animals...

Functionalized multi-walled carbon nanotube based sensors for distributed methane leak detection

EPA Science Inventory

This paper presents a highly sensitive, energy efficient and low-cost distributed methane (CH4) sensor system (DMSS) for continuous monitoring, detection and localization of CH4 leaks in natural gas infrastructure such as transmission and distribution pipelines, wells, and produc...

Aspergillus oryzae-based cell factory for direct kojic acid production from cellulose.

PubMed

Yamada, Ryosuke; Yoshie, Toshihide; Wakai, Satoshi; Asai-Nakashima, Nanami; Okazaki, Fumiyoshi; Ogino, Chiaki; Hisada, Hiromoto; Tsutsumi, Hiroko; Hata, Yoji; Kondo, Akihiko

2014-05-18

Kojic acid (5-Hydroxy-2-(hydroxymethyl)-4-pyrone) is one of the major secondary metabolites in Aspergillus oryzae. It is widely used in food, pharmaceuticals, and cosmetics. The production cost, however, is too high for its use in many applications. Thus, an efficient and cost-effective kojic acid production process would be valuable. However, little is known about the complete set of genes for kojic acid production. Currently, kojic acid is produced from glucose. The efficient production of kojic acid using cellulose as an inexpensive substrate would help establish cost-effective kojic acid production. A kojic acid transcription factor gene over-expressing the A. oryzae strain was constructed. Three genes related to kojic acid production in this strain were transcribed in higher amounts than those found in the wild-type strain. This strain produced 26.4 g/L kojic acid from 80 g/L glucose. Furthermore, this strain was transformed with plasmid harboring 3 cellulase genes. The resultant A. oryzae strain successfully produced 0.18 g/L of kojic acid in 6 days of fermentation from the phosphoric acid swollen cellulose. Kojic acid was produced directly from cellulose material using genetically engineered A. oryzae. Because A. oryzae has efficient protein secretion ability and secondary metabolite productivity, an A. oryzae-based cell factory could be a platform for the production of various kinds of bio-based chemicals.

Aspergillus oryzae-based cell factory for direct kojic acid production from cellulose

PubMed Central

2014-01-01

Background Kojic acid (5-Hydroxy-2-(hydroxymethyl)-4-pyrone) is one of the major secondary metabolites in Aspergillus oryzae. It is widely used in food, pharmaceuticals, and cosmetics. The production cost, however, is too high for its use in many applications. Thus, an efficient and cost-effective kojic acid production process would be valuable. However, little is known about the complete set of genes for kojic acid production. Currently, kojic acid is produced from glucose. The efficient production of kojic acid using cellulose as an inexpensive substrate would help establish cost-effective kojic acid production. Results A kojic acid transcription factor gene over-expressing the A. oryzae strain was constructed. Three genes related to kojic acid production in this strain were transcribed in higher amounts than those found in the wild-type strain. This strain produced 26.4 g/L kojic acid from 80 g/L glucose. Furthermore, this strain was transformed with plasmid harboring 3 cellulase genes. The resultant A. oryzae strain successfully produced 0.18 g/L of kojic acid in 6 days of fermentation from the phosphoric acid swollen cellulose. Conclusions Kojic acid was produced directly from cellulose material using genetically engineered A. oryzae. Because A. oryzae has efficient protein secretion ability and secondary metabolite productivity, an A. oryzae-based cell factory could be a platform for the production of various kinds of bio-based chemicals. PMID:24885968

Effect of Clouds on Apertures of Space-based Air Fluorescence Detectors

NASA Technical Reports Server (NTRS)

Sokolsky, P.; Krizmanic, J.

2003-01-01

Space-based ultra-high-energy cosmic ray detectors observe fluorescence light from extensive air showers produced by these particles in the troposphere. Clouds can scatter and absorb this light and produce systematic errors in energy determination and spectrum normalization. We study the possibility of using IR remote sensing data from MODIS and GOES satellites to delimit clear areas of the atmosphere. The efficiency for detecting ultra-high-energy cosmic rays whose showers do not intersect clouds is determined for real, night-time cloud scenes. We use the MODIS SST cloud mask product to define clear pixels for cloud scenes along the equator and use the OWL Monte Carlo to generate showers in the cloud scenes. We find the efficiency for cloud-free showers with closest approach of three pixels to a cloudy pixel is 6.5% exclusive of other factors. We conclude that defining a totally cloud-free aperture reduces the sensitivity of space-based fluorescence detectors to unacceptably small levels.

Thermally insulating and fire-retardant lightweight anisotropic foams based on nanocellulose and graphene oxide.

PubMed

Wicklein, Bernd; Kocjan, Andraž; Salazar-Alvarez, German; Carosio, Federico; Camino, Giovanni; Antonietti, Markus; Bergström, Lennart

2015-03-01

High-performance thermally insulating materials from renewable resources are needed to improve the energy efficiency of buildings. Traditional fossil-fuel-derived insulation materials such as expanded polystyrene and polyurethane have thermal conductivities that are too high for retrofitting or for building new, surface-efficient passive houses. Tailored materials such as aerogels and vacuum insulating panels are fragile and susceptible to perforation. Here, we show that freeze-casting suspensions of cellulose nanofibres, graphene oxide and sepiolite nanorods produces super-insulating, fire-retardant and strong anisotropic foams that perform better than traditional polymer-based insulating materials. The foams are ultralight, show excellent combustion resistance and exhibit a thermal conductivity of 15 mW m(-1) K(-1), which is about half that of expanded polystyrene. At 30 °C and 85% relative humidity, the foams retained more than half of their initial strength. Our results show that nanoscale engineering is a promising strategy for producing foams with excellent properties using cellulose and other renewable nanosized fibrous materials.

Production of neutron-rich nuclei approaching r-process by gamma-induced fission of 238U at ELI-NP

NASA Astrophysics Data System (ADS)

Mei, Bo; Balabanski, Dimiter; Constantin, Paul; Anh Le, Tuan; Viet Cuong, Phan

2018-05-01

The investigation of neutron-rich exotic nuclei is crucial not only for nuclear physics but also for nuclear astrophysics. Experimentally, only few neutron-rich nuclei near the stability have been studied, however, most neutron-rich nuclei have not been measured due to their small production cross sections as well as short half-lives. At ELI-NP, gamma beams with high intensities will open new opportunities to investigate very neutron-rich fragments produced by photofission of 238U targets in a gas cell. Based on some simulations, a novel gas cell has been designed to produce, stop and extract 238U photofission fragments. The extraction time and efficiency of photofission fragments have been optimized by using SIMION simulations. According to these simulations, a high extraction efficiency and a short extraction time can be achieved for 238U photofission fragments in the gas cell, which will allow one to measure very neutron-rich fragments with short half-lives by using the IGISOL facility proposed at ELI-NP.

Semiconductor photoelectrochemistry

NASA Technical Reports Server (NTRS)

Buoncristiani, A. M.; Byvik, C. E.

1983-01-01

Semiconductor photoelectrochemical reactions are investigated. A model of the charge transport processes in the semiconductor, based on semiconductor device theory, is presented. It incorporates the nonlinear processes characterizing the diffusion and reaction of charge carriers in the semiconductor. The model is used to study conditions limiting useful energy conversion, specifically the saturation of current flow due to high light intensity. Numerical results describing charge distributions in the semiconductor and its effects on the electrolyte are obtained. Experimental results include: an estimate rate at which a semiconductor photoelectrode is capable of converting electromagnetic energy into chemical energy; the effect of cell temperature on the efficiency; a method for determining the point of zero zeta potential for macroscopic semiconductor samples; a technique using platinized titanium dioxide powders and ultraviolet radiation to produce chlorine, bromine, and iodine from solutions containing their respective ions; the photoelectrochemical properties of a class of layered compounds called transition metal thiophosphates; and a technique used to produce high conversion efficiency from laser radiation to chemical energy.

Optimization of pretreatment, enzymatic hydrolysis and fermentation for more efficient ethanol production by Jerusalem artichoke stalk.

PubMed

Li, Kai; Qin, Jin-Cheng; Liu, Chen-Guang; Bai, Feng-Wu

2016-12-01

Jerusalem artichoke (JA) is a potential energy crop for biorefinery due to its unique agronomic traits such as resistance to environmental stresses and high biomass yield in marginal lands. Although JA tubers have been explored for inulin extraction and biofuels production, there is little concern on its stalk (JAS). In this article, the pretreatment of JAS by alkaline hydrogen peroxide was optimized using the response surface methodology to improve sugars yield and reduce chemicals usage. Scanning electron microscopy, X-ray diffraction, and thermogravimetric analysis were applied to characterize the structures of the pretreated JAS to evaluate the effectiveness of the pretreatment. Furthermore, the feeding of the pretreated JAS and cellulase was performed for high solid uploading (up to 30%) to increase ethanol titer, and simultaneous saccharification and fermentation with 55.6g/L ethanol produced, 36.5% more than that produced through separate hydrolysis and fermentation, was validated to be more efficient. Copyright © 2016 Elsevier Ltd. All rights reserved.

Devitrite-based optical diffusers.

PubMed

Butt, Haider; Knowles, Kevin M; Montelongo, Yunuen; Amaratunga, Gehan A J; Wilkinson, Timothy D

2014-03-25

Devitrite is a novel material produced by heat treatment of commercial soda-lime-silica glass. It consists of fans of needle-like crystals which can extend up to several millimeters and have interspacings of up to a few hundred nanometers. To date, only the material properties of devitrite have been reported, and there has been a distinct lack of research on using it for optical applications. In this study, we demonstrate that randomly oriented fans of devitrite crystals can act as highly efficient diffusers for visible light. Devitrite crystals produce phase modulation of light because of their relatively high anisotropy. The nanoscale spacings between these needles enable light to be diffused to large scattering angles. Experimentally measured results suggest that light diffusion patterns with beam widths of up to 120° are produced. Since devitrite is an inexpensive material to produce, it has the potential to be used in a variety of commercial applications.

Cloning and expression of the gene for bacteriophage T7 RNA polymerase

DOEpatents

Studier, F. William; Davanloo, Parichehre; Rosenberg, Alan H.; Moffatt, Barbara A.; Dunn, John J.

1999-02-09

This application describes a means to clone a functional gene for bacteriophage T7 RNA polymerase. Active T7 RNA polymerase is produced from the cloned gene, and a plasmid has been constructed that can produce the active enzyme in large amounts. T7 RNA polymerase transcribes DNA very efficiently and is highly selective for a relatively long promoter sequence. This enzyme is useful for synthesizing large amounts of RNA in vivo or in vitro, and is capable of producing a single RNA selectively from a complex mixture of DNAs. The procedure used to obtain a clone of the R7 RNA polymerase gene can be applied to other T7-like phages to obtain clones that produce RNA polymerases having different promoter specificities, different bacterial hosts, or other desirable properties. T7 RNA polymerase is also used in a system for selective, high-level synthesis of RNAs and proteins in suitable host cells.

Cloning and expression of the gene for bacteriophage T7 RNA polymerase

DOEpatents

Studier, F. William; Davanloo, Parichehre; Rosenberg, Alan H.; Moffatt, Barbara A.; Dunn, John J.

1997-12-02

This application describes a means to clone a functional gene for bacteriophage T7 RNA polymerase. Active T7 RNA polymerase is produced from the cloned gene, and a plasmid has been constructed that can produce the active enzyme in large amounts. T7 RNA polymerase transcribes DNA very efficiently and is highly selective for a relatively long promoter sequence. This enzyme is useful for synthesizing large amounts of RNA in vivo or in vitro, and is capable of producing a single RNA selectively from a complex mixture of DNAs. The procedure used to obtain a clone of the R7 RNA polymerase gene can be applied to other T7-like phages to obtain clones that produce RNA polymerases having different promoter specificities, different bacterial hosts, or other desirable properties. T7 RNA polymerase is also used in a system for selective, high-level synthesis of RNAs and proteins in suitable host cells.

Cloning and expression of the gene for bacteriophage T7 RNA polymerase

DOEpatents

Studier, F. William; Davanloo, Parichehre; Rosenberg, Alan H.; Moffatt, Barbara A.; Dunn, John J.

1990-01-01

This application describes a means to clone a functional gene for bacteriophage T7 RNA polymerase. Active T7 RNA polymerase is produced from the cloned gene, and a plasmid has been constructed that can produce the active enzyme in large amounts. T7 RNA polymerase transcribes DNA very efficiently and is highly selective for a relatively long promoter sequence. This enzyme is useful for synthesizing large amounts of RNA in vivo or in vitro, and is capable of producing a single RNA selectively from a complex mixture of DNAs. The procedure used to obtain a clone of the T7 RNA polymerase gene can be applied to other T7-like phages to obtain clones that produce RNA polymerases having different promoter specificities, different bacterial hosts, or other desirable properties. T7 RNA polymerase is also used in a system for selective, high-level synthesis of RNAs and proteins in suitable host cells.

Solar energy collection system

NASA Technical Reports Server (NTRS)

Miller, C. G.; Stephens, J. B. (Inventor)

1979-01-01

A fixed, linear, ground-based primary reflector having an extended curved sawtooth-contoured surface covered with a metalized polymeric reflecting material, reflects solar energy to a movably supported collector that is kept at the concentrated line focus reflector primary. The primary reflector may be constructed by a process utilizing well known freeway paving machinery. The solar energy absorber is preferably a fluid transporting pipe. Efficient utilization leading to high temperatures from the reflected solar energy is obtained by cylindrical shaped secondary reflectors that direct off-angle energy to the absorber pipe. A seriatim arrangement of cylindrical secondary reflector stages and spot-forming reflector stages produces a high temperature solar energy collection system of greater efficiency.

Highly Selective Photothermal Therapy by a Phenoxylated-Dextran-Functionalized Smart Carbon Nanotube Platform.

PubMed

Han, Seungmin; Kwon, Taeyun; Um, Jo-Eun; Haam, Seungjoo; Kim, Woo-Jae

2016-05-01

Near-infrared (NIR) photothermal therapy using biocompatible single-walled carbon nanotubes (SWNTs) is advantageous because as-produced SWNTs, without additional size control, both efficiently absorb NIR light and demonstrate high photothermal conversion efficiency. In addition, covalent attachment of receptor molecules to SWNTs can be used to specifically target infected cells. However, this technique interrupts SWNT optical properties and inevitably lowers photothermal conversion efficiency and thus remains major hurdle for SWNT applications. This paper presents a smart-targeting photothermal therapy platform for inflammatory disease using newly developed phenoxylated-dextran-functionalized SWNTs. Phenoxylated dextran is biocompatible and efficiently suspends SWNTs by noncovalent π-π stacking, thereby minimizing SWNT bundle formations and maintaining original SWNT optical properties. Furthermore, it selectively targets inflammatory macrophages by scavenger-receptor binding without any additional receptor molecules; therefore, its preparation is a simple one-step process. Herein, it is experimentally demonstrated that phenoxylated dextran-SWNTs (pD-SWNTs) are also biocompatible, selectively penetrate inflammatory macrophages over normal cells, and exhibit high photothermal conversion efficiency. Consequently, NIR laser-triggered macrophage treatment can be achieved with high accuracy by pD-SWNT without damaging receptor-free cells. These smart targeting materials can be a novel photothermal agent candidate for inflammatory disease. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Melt-cast organic glasses as high-efficiency fast neutron scintillators

NASA Astrophysics Data System (ADS)

Carlson, Joseph S.; Feng, Patrick L.

2016-10-01

In this work we report a new class of organic-based scintillators that combines several of the desirable attributes of existing crystalline, liquid, and plastic organic scintillators. The prepared materials may be isolated in single crystalline form or melt-cast to produce highly transparent glasses that have been shown to provide high light yields of up to 16,000 photons/MeVee, as evaluated against EJ-200 plastic scintillators and solution-grown trans-stilbene crystals. The prepared organic glasses exhibit neutron/gamma pulse-shape discrimination (PSD) and are compatible with wavelength shifters to reduce optical self-absorption effects that are intrinsic to pure materials such as crystalline organics. The combination of high scintillation efficiency, PSD capabilities, and facile scale-up via melt-casting distinguishes this new class of amorphous materials from existing alternatives.

High-level generation of polyclonal antibodies by genetic immunization.

PubMed

Chambers, Ross S; Johnston, Stephen Albert

2003-09-01

Antibodies are important tools for investigating the proteome, but current methods for producing them have become a rate-limiting step. A primary obstacle in most methods for generating antibodies or antibody-like molecules is the requirement for at least microgram quantities of purified protein. We have developed a technology for producing antibodies using genetic immunization. Genetic immunization-based antibody production offers several advantages, including high throughput and high specificity. Moreover, antibodies produced from genetically immunized animals are more likely to recognize the native protein. Here we show that a genetic immunization-based system can be used to efficiently raise useful antibodies to a wide range of antigens. We accomplished this by linking the antigen gene to various elements that enhance antigenicity and by codelivering plasmids encoding genetic adjuvants. Our system, which was tested by immunizing mice with >130 antigens, has shown a final success rate of 84%.

Antibody Production in Plants and Green Algae.

PubMed

Yusibov, Vidadi; Kushnir, Natasha; Streatfield, Stephen J

2016-04-29

Monoclonal antibodies (mAbs) have a wide range of modern applications, including research, diagnostic, therapeutic, and industrial uses. Market demand for mAbs is high and continues to grow. Although mammalian systems, which currently dominate the biomanufacturing industry, produce effective and safe recombinant mAbs, they have a limited manufacturing capacity and high costs. Bacteria, yeast, and insect cell systems are highly scalable and cost effective but vary in their ability to produce appropriate posttranslationally modified mAbs. Plants and green algae are emerging as promising production platforms because of their time and cost efficiencies, scalability, lack of mammalian pathogens, and eukaryotic posttranslational protein modification machinery. So far, plant- and algae-derived mAbs have been produced predominantly as candidate therapeutics for infectious diseases and cancer. These candidates have been extensively evaluated in animal models, and some have shown efficacy in clinical trials. Here, we review ongoing efforts to advance the production of mAbs in plants and algae.

Production and characterization of vaccines based on flaviviruses defective in replication

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

Mason, Peter W.; Department of Pathology, University of Texas Medical Branch, 301 University Boulevard, Galveston, TX 77555-1019; Sealy Center for Vaccine Development, University of Texas Medical Branch, 301 University Boulevard, Galveston, TX 77555-1019

2006-08-01

To develop new vaccine candidates for flavivirus infections, we have engineered two flaviviruses, yellow fever virus (YFV) and West Nile virus (WNV), that are deficient in replication. These defective pseudoinfectious viruses (PIVs) lack a functional copy of the capsid (C) gene in their genomes and are incapable of causing spreading infection upon infection of cells both in vivo and in vitro. However, they produce extracellular E protein in form of secreted subviral particles (SVPs) that are known to be an effective immunogen. PIVs can be efficiently propagated in trans-complementing cell lines making high levels of C or all three viralmore » structural proteins. PIVs derived from YFV and WNV, demonstrated very high safety and immunization produced high levels of neutralizing antibodies and protective immune response. Such defective flaviviruses can be produced in large scale under low biocontainment conditions and should be useful for diagnostic or vaccine applications.« less

Holographic spectrum-splitting optical systems for solar photovoltaics

NASA Astrophysics Data System (ADS)

Zhang, Deming

Solar energy is the most abundant source of renewable energy available. The relatively high cost prevents solar photovoltaic (PV) from replacing fossil fuel on a larger scale. In solar PV power generation the cost is reduced with more efficient PV technologies. In this dissertation, methods to improve PV conversion efficiency with holographic optical components are discussed. The tandem multiple-junction approach has achieved very high conversion efficiency. However it is impossible to manufacture tandem PV cells at a low cost due to stringent fabrication standards and limited material types that satisfy lattice compatibility. Current produced by the tandem multi-junction PV cell is limited by the lowest junction due to series connection. Spectrum-splitting is a lateral multi-junction concept that is free of lattice and current matching constraints. Each PV cell can be optimized towards full absorption of a spectral band with tailored light-trapping schemes. Holographic optical components are designed to achieve spectrum-splitting PV energy conversion. The incident solar spectrum is separated onto multiple PV cells that are matched to the corresponding spectral band. Holographic spectrum-splitting can take advantage of existing and future low-cost technologies that produces high efficiency thin-film solar cells. Spectrum-splitting optical systems are designed and analyzed with both transmission and reflection holographic optical components. Prototype holograms are fabricated and high optical efficiency is achieved. Light-trapping in PV cells increases the effective optical path-length in the semiconductor material leading to improved absorption and conversion efficiency. It has been shown that the effective optical path length can be increased by a factor of 4n2 using diffusive surfaces. Ultra-light-trapping can be achieved with optical filters that limit the escape angle of the diffused light. Holographic reflection gratings have been shown to act as angle-wavelength selective filters that can function as ultra-light-trapping filters. Results from an experimental reflection hologram are used to model the absorption enhancement factor for a silicon solar cell and light-trapping filter. The result shows a significant improvement in current generation for thin-film silicon solar cells under typical operating conditions.

Generating free charges by carrier multiplication in quantum dots for highly efficient photovoltaics.

PubMed

Ten Cate, Sybren; Sandeep, C S Suchand; Liu, Yao; Law, Matt; Kinge, Sachin; Houtepen, Arjan J; Schins, Juleon M; Siebbeles, Laurens D A

2015-02-17

CONSPECTUS: In a conventional photovoltaic device (solar cell or photodiode) photons are absorbed in a bulk semiconductor layer, leading to excitation of an electron from a valence band to a conduction band. Directly after photoexcitation, the hole in the valence band and the electron in the conduction band have excess energy given by the difference between the photon energy and the semiconductor band gap. In a bulk semiconductor, the initially hot charges rapidly lose their excess energy as heat. This heat loss is the main reason that the theoretical efficiency of a conventional solar cell is limited to the Shockley-Queisser limit of ∼33%. The efficiency of a photovoltaic device can be increased if the excess energy is utilized to excite additional electrons across the band gap. A sufficiently hot charge can produce an electron-hole pair by Coulomb scattering on a valence electron. This process of carrier multiplication (CM) leads to formation of two or more electron-hole pairs for the absorption of one photon. In bulk semiconductors such as silicon, the energetic threshold for CM is too high to be of practical use. However, CM in nanometer sized semiconductor quantum dots (QDs) offers prospects for exploitation in photovoltaics. CM leads to formation of two or more electron-hole pairs that are initially in close proximity. For photovoltaic applications, these charges must escape from recombination. This Account outlines our recent progress in the generation of free mobile charges that result from CM in QDs. Studies of charge carrier photogeneration and mobility were carried out using (ultrafast) time-resolved laser techniques with optical or ac conductivity detection. We found that charges can be extracted from photoexcited PbS QDs by bringing them into contact with organic electron and hole accepting materials. However, charge localization on the QD produces a strong Coulomb attraction to its counter charge in the organic material. This limits the production of free charges that can contribute to the photocurrent in a device. We show that free mobile charges can be efficiently produced via CM in solids of strongly coupled PbSe QDs. Strong electronic coupling between the QDs resulted in a charge carrier mobility of the order of 1 cm(2) V(-1) s(-1). This mobility is sufficiently high so that virtually all electron-hole pairs escape from recombination. The impact of temperature on the CM efficiency in PbSe QD solids was also studied. We inferred that temperature has no observable effect on the rate of cooling of hot charges nor on the CM rate. We conclude that exploitation of CM requires that charges have sufficiently high mobility to escape from recombination. The contribution of CM to the efficiency of photovoltaic devices can be further enhanced by an increase of the CM efficiency above the energetic threshold of twice the band gap. For large-scale applications in photovoltaic devices, it is important to develop abundant and nontoxic materials that exhibit efficient CM.

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

Erga, O.; Finborud, A.

Cost-effective FGD processes with high SO{sub 2} removal efficiencies are required for fossil-fired power plants. With high-sulfur fuel, conventional limestone processes are less ideal, and regenerative processes with SO{sub 2} recovery may offer important advantages. The Elsorb process, which is being developed by the Norwegian company Elkem Technology a.s., is a regenerable SO{sub 2} recovery process which operates on the principle of chemical absorption followed by regeneration by evaporation. The process is based on the use of a chemical stable sodium phosphate buffer in high concentration. It combines high cleaning efficiency with high cyclic absorption capacity, moderate energy requirement, andmore » very little oxidation losses. The process produces SO{sub 2} (g) which can be converted into liquid SO{sub 2}, sulfuric acid or elemental sulfur. The Elsorb process has been pilot tested on flue gas from a coal-fired boiler with very promising results, concerning cleaning efficiency and oxidation losses of SO{sub 2}. The first commercial Elsorb plant has been installed for treating incinerated Claus tail gas. Preliminary data regarding cleaning efficiency are in accordance with the pilot tests. However, unexpected high consumption of make-up chemicals were encountered. The existing incinerator is now to be modified. Complete data for the Elsorb plant should be available later this year. 1 fig.« less

New Metamaterials with Combined Subnano - and Mesoscale Topology for High-efficiency Catalytic Combustion Chambers of Innovative Gas Turbine Engines

NASA Astrophysics Data System (ADS)

Knysh, Yu A.; Xanthopoulou, G. G.

2018-01-01

The object of the study is a catalytic combustion chamber that provides a highly efficient combustion process through the use of effects: heat recovery from combustion, microvortex heat transfer, catalytic reaction and acoustic resonance. High efficiency is provided by a complex of related technologies: technologies for combustion products heat transfer (recuperation) to initial mixture, catalytic processes technology, technology for calculating effective combustion processes based on microvortex matrices, technology for designing metamaterials structures and technology for obtaining the required topology product by laser fusion of metal powder compositions. The mesoscale level structure provides combustion process with the use of a microvortex effect with a high intensity of heat and mass transfer. High surface area (extremely high area-to-volume ratio) created due to nanoscale periodic structure and ensures catalytic reactions efficiency. Produced metamaterial is the first multiscale product of new concept which due to combination of different scale level periodic topologies provides qualitatively new set of product properties. This research is aimed at solving simultaneously two global problems of the present: ensure environmental safety of transport systems and power industry, as well as the economy and rational use of energy resources, providing humanity with energy now and in the foreseeable future.

Aerosol Generation by Modern Flush Toilets.

PubMed

Johnson, David; Lynch, Robert; Marshall, Charles; Mead, Kenneth; Hirst, Deborah

A microbe-contaminated toilet will produce bioaerosols when flushed. We assessed toilet plume aerosol from high efficiency (HET), pressure-assisted high efficiency (PAT), and flushometer (FOM) toilets with similar bowl water and flush volumes. Total and droplet nuclei "bioaerosols" were assessed. Monodisperse 0.25-1.9- μ m fluorescent microspheres served as microbe surrogates in separate trials in a mockup 5 m 3 water closet (WC). Bowl water seeding was approximately 10 12 particles/mL. Droplet nuclei were sampled onto 0.2- μ m pore size mixed cellulose ester filters beginning 15 min after the flush using open-face cassettes mounted on the WC walls. Pre- and postflush bowl water concentrations were measured. Filter particle counts were analyzed via fluorescent microscopy. Bowl headspace droplet count size distributions were bimodal and similar for all toilet types and flush conditions, with 95% of droplets < 2 μ m diameter and > 99% < 5 μ m. Up to 145,000 droplets were produced per flush, with the high-energy flushometer producing over three times as many as the lower energy PAT and over 12 times as many as the lowest energy HET despite similar flush volumes. The mean numbers of fluorescent droplet nuclei particles aerosolized and remaining airborne also increased with flush energy. Fluorescent droplet nuclei per flush decreased with increasing particle size. These findings suggest two concurrent aerosolization mechanisms-splashing for large droplets and bubble bursting for the fine droplets that form droplet nuclei.

Development of Thermoelectric and Permanent Magnet Nanoparticles for Clean Energy Applications

NASA Astrophysics Data System (ADS)

Nguyen, Phi-Khanh

The global trend towards energy efficiency and environmental sustainability has generated a strong demand for clean energy technologies. Among the many energy solutions, the work in this dissertation contributes to two strategic goals: the reduction of fuel consumption in the transportation sector, and the increase of domestic wind power capacity. The key barriers to achieving these goals are materials challenges. Automobiles can be made more efficient by thermoelectric conversion of waste heat from the engine into electricity that can be used to power electrical components in the vehicle. Vehicles can forego petroleum fuel altogether by using electric or hybrid motors. Unfortunately, the conversion efficiency of current thermoelectric technology is too low to be considered economically feasible, and the permanent magnets used in electric vehicle motors and wind turbine generators require critical rare-earth elements that are economically unstable (often referred to as the "rare-earth crisis"). In order to combat these challenges, a "spark erosion" technique was utilized for producing nanoparticles that improve thermoelectric efficiency and contribute to the development of electromotors that do not require rare-earths. In Chapter 2 of this dissertation, I describe the utilization of spark erosion for producing high-quality thermoelectric nanoparticles at a remarkably high rate and with enhanced thermoelectric properties. The technique was employed to synthesize p-type bismuth-antimony telluride (BST) and n-type skutterudite nanoparticles, using a relatively small laboratory apparatus, with low energy consumption. The compacted BST nanocomposite samples made from these nanoparticles exhibit a well-defined, 20--50 nm size nanograin microstructure, and show an enhanced Figure of merit, ZT, of 1.36 at 360 K due to a reduction in lattice thermal conductivity. The skutterudite nanocomposites also show reduced thermal conductivity but still require enhancement in the thermoelectric power factor. Such a technique is essential for providing inexpensive, oxidation-free nanoparticles required for fabricating high performance thermoelectric devices for power generation from waste heat, and for refrigeration. We have investigated the spark erosion of MnBi, a promising rare-earth-free permanent magnet, and have determined that spark erosion provides the best approach for producing MnBi particles. The low-temperature phase of MnBi (LTP-MnBi) is an attractive rare-earth free permanent magnet material due it its high uniaxial magnetocrystalline anisotropy, which produces an unusually high coercivity at the elevated temperatures required for motor and generators. However, due to the peritectic Mn-Bi phase diagram and the slow interdiffusion of Mn and Bi below the 350°C phase change temperature, bulk samples of LTP-MnBi with high saturation magnetization (MS) have been difficult to achieve. In Chapter 3, we describe the successful formation of high-purity bulk LTP-MnBi ingots and spark erosion of this material to produce single-domain particles of MnBi at an unprecedented rate. The bulk ingots have MS > 90 wt % of LTP-MnBi, and are formed by chill-casting and by vacuum-annealing of arc-melted ingots. The as-prepared powder then consists of amorphous, crystalline, and superparamagnetic particles, mostly as porous aggregates. The major fraction of the powder consists of 20--30 nm particles. A short anneal crystallizes the amorphous particles producing a high moment, albeit with HC of only a few kOe. If lightly milled, the agglomerates are broken up and yield an HC of 1 T and a maximum energy product of 3.0 MGOe. The particles can be further engineered through milling, annealing, and/or solution processing in order to produce unique properties that hold promise to achieving the first bulk permanent magnet that utilizes the exchange-spring principle. In addition, we have found that due to the amorphous component of the spark-eroded powder, a cold compact can be magnetically oriented by crystallizing in a magnetic field. This crystallographic alignment is necessary for further improvement of the magnet energy density.

Strong antenna-enhanced fluorescence of a single light-harvesting complex shows photon antibunching

PubMed Central

Wientjes, Emilie; Renger, Jan; Curto, Alberto G.; Cogdell, Richard; van Hulst, Niek F.

2014-01-01

The nature of the highly efficient energy transfer in photosynthetic light-harvesting complexes is a subject of intense research. Unfortunately, the low fluorescence efficiency and limited photostability hampers the study of individual light-harvesting complexes at ambient conditions. Here we demonstrate an over 500-fold fluorescence enhancement of light-harvesting complex 2 (LH2) at the single-molecule level by coupling to a gold nanoantenna. The resonant antenna produces an excitation enhancement of circa 100 times and a fluorescence lifetime shortening to ~\

Strong antenna-enhanced fluorescence of a single light-harvesting complex shows photon antibunching

NASA Astrophysics Data System (ADS)

Wientjes, Emilie; Renger, Jan; Curto, Alberto G.; Cogdell, Richard; van Hulst, Niek F.

2014-06-01

The nature of the highly efficient energy transfer in photosynthetic light-harvesting complexes is a subject of intense research. Unfortunately, the low fluorescence efficiency and limited photostability hampers the study of individual light-harvesting complexes at ambient conditions. Here we demonstrate an over 500-fold fluorescence enhancement of light-harvesting complex 2 (LH2) at the single-molecule level by coupling to a gold nanoantenna. The resonant antenna produces an excitation enhancement of circa 100 times and a fluorescence lifetime shortening to ~\

An Efficient, Optimized Synthesis of Fentanyl and Related Analogs

DOE PAGES

Valdez, Carlos A.; Leif, Roald N.; Mayer, Brian P.; ...

2014-09-18

The alternate and optimized syntheses of the parent opioid fentanyl and its analogs are described. The routes presented exhibit high-yielding transformations leading to these powerful analgesics after optimization studies were carried out for each synthetic step. The general three-step strategy produced a panel of four fentanyls in excellent yields (73–78%) along with their more commonly encountered hydrochloride and citric acid salts. In conclusion, the following strategy offers the opportunity for the gram-scale, efficient production of this interesting class of opioid alkaloids.

An Efficient, Optimized Synthesis of Fentanyl and Related Analogs

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

Valdez, Carlos A.; Leif, Roald N.; Mayer, Brian P.

The alternate and optimized syntheses of the parent opioid fentanyl and its analogs are described. The routes presented exhibit high-yielding transformations leading to these powerful analgesics after optimization studies were carried out for each synthetic step. The general three-step strategy produced a panel of four fentanyls in excellent yields (73–78%) along with their more commonly encountered hydrochloride and citric acid salts. In conclusion, the following strategy offers the opportunity for the gram-scale, efficient production of this interesting class of opioid alkaloids.

Improving efficiency of polystyrene concrete production with composite binders

NASA Astrophysics Data System (ADS)

Lesovik, R. V.; Ageeva, M. S.; Lesovik, G. A.; Sopin, D. M.; Kazlitina, O. V.; Mitrokhina, A. A.

2018-03-01

According to leading marketing researchers, the construction market in Russia and CIS will continue growing at a rapid rate; this applies not only to a large-scale major construction, but to a construction of single-family houses and small-scale industrial facilities as well. Due to this, there are increased requirements for heat insulation of the building enclosures and a significant demand for efficient walling materials with high thermal performance. All these developments led to higher requirements imposed on the equipment that produces such materials.

Ultra clean burner for an AMTEC system suitable for hybrid electric vehicles

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

Mital, R.; Sievers, R.K.; Hunt, T.K.

1997-12-31

High power Alkali Metal Thermal to Electric Converter (AMTEC) systems have the potential to make the hybrid electric vehicle (HEV) program a success by meeting the challenging standards put forth by the EPA for the automobile industry. The premise of the whole concept of using AMTEC cells, as discussed by Hunt et al. (1995), for power generation in HEV`s is based on the utilization of a high efficiency external combustion system. The key requirement being a burner which will produce extremely low quantities of carbon monoxide and oxides of nitrogen, emit minimal amounts of hydrocarbon, will have high radiative andmore » convective efficiencies and at least a 4:1 turndown ratio. This work presents one such burner which has the potential to meet all of these demands and more. After investigation of a number of burners, including, metal fiber, ported metal, ceramic fiber and ported ceramic, it is believed that cellular ceramic burners will be the best candidates for integration with AMTEC cells for a high power system suitable for hybrid electric vehicles. A detailed study which includes the operating range, radiation efficiency, total heat transfer efficiency, spectral intensity, exit gas temperature and pollutant emission indices measurement has been carried out on circular and square shaped burners. Total heat transfer efficiencies as high as 65--70% have been measured using a water calorimeter. With efficient recuperation, a burner/recuperator efficiency of 80% at peak power and 90% at peak efficiency operating points are conceivable with this burner. Establishment of combustion within the porous matrix leads to low peak temperatures and hence lower NO{sub x}. The emission indices of CO and HC are also quite low. The stability range measurements show a 6:1 turndown ratio at an equivalence ratio of 0.9.« less

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

Shaw, B. H.; Applied Science and Technology, University of California, Berkeley, California 94720; Tilborg, J. van

Solid-based surface high-harmonic generation from a tape is experimentally studied. By operating at mildly relativistic normalized laser strengths a{sub 0}≲0.2, harmonics up to the 17th order are efficiently produced in the coherent wake emission (CWE) regime. CWE pulse properties, such as divergence, energy, conversion efficiency, and spectrum, are investigated for various tape materials and drive laser conditions. A clear correlation between surface roughness and harmonic beam divergence is found. At the measured pulse properties for the 15th harmonic (conversion efficiency ∼6.5×10{sup −7}, divergence ∼7−15 mrad), the 100-mJ-level drive laser produces several MWs of extreme ultra-violet pulses. The spooling tape configurationmore » enables multi-Hz operation over thousands of shots, making this source attractive as a seed to the few-Hz laser-plasma-accelerator-driven free-electron laser (FEL). Models indicate that these CWE pulses with MW level powers are sufficient for seed-induced bunching and FEL gain.« less

Chemical composition, pretreatments and saccharification of Senna siamea (Lam.) H.S. Irwin & Barneby: An efficient biomass producing tree legume.

PubMed

Mund, Nitesh K; Dash, Debabrata; Barik, Chitta R; Goud, Vaibhav V; Sahoo, Lingaraj; Mishra, Prasannajit; Nayak, Nihar R

2016-05-01

Protocols were developed for efficient release of glucose from the biomass of Senna siamea, one of the highly efficient biomass producing tree legumes. Composition of mature, 1year and 2years coppice biomass were analysed. For the hydrolysis of the glucan, two pretreatments, cellulose solvent- and organic solvent-based lignocellulose fractionation (COSLIF) and alkali (sodium hydroxide) were used; COSLIF (85% phosphoric acid, 45min incubation at 50°C) pretreated mature biomass exhibited best result in which 88.90% glucose released after 72h of incubation with the use of 5 filter paper units (FPU) of cellulase and 10 international units (IU) of β-glucosidase per gram of glucan. Of the biomass of different particle sizes (40-200mesh) used for saccharification, 40-60mesh shown the maximum glucose release. COSLIF pretreated mature, 1year and 2years coppice biomass showed equivalent glucose release profiles. Copyright © 2016 Elsevier Ltd. All rights reserved.

Phosphate-binding pocket in Dicer-2 PAZ domain for high-fidelity siRNA production

PubMed Central

Kandasamy, Suresh K.

2016-01-01

The enzyme Dicer produces small silencing RNAs such as micro-RNAs (miRNAs) and small interfering RNAs (siRNAs). In Drosophila, Dicer-1 produces ∼22–24-nt miRNAs from pre-miRNAs, whereas Dicer-2 makes 21-nt siRNAs from long double-stranded RNAs (dsRNAs). How Dicer-2 precisely makes 21-nt siRNAs with a remarkably high fidelity is unknown. Here we report that recognition of the 5′-monophosphate of a long dsRNA substrate by a phosphate-binding pocket in the Dicer-2 PAZ (Piwi, Argonaute, and Zwille/Pinhead) domain is crucial for the length fidelity, but not the efficiency, in 21-nt siRNA production. Loss of the length fidelity, meaning increased length heterogeneity of siRNAs, caused by point mutations in the phosphate-binding pocket of the Dicer-2 PAZ domain decreased RNA silencing activity in vivo, showing the importance of the high fidelity to make 21-nt siRNAs. We propose that the 5′-monophosphate of a long dsRNA substrate is anchored by the phosphate-binding pocket in the Dicer-2 PAZ domain and the distance between the pocket and the RNA cleavage active site in the RNaseIII domain corresponds to the 21-nt pitch in the A-form duplex of a long dsRNA substrate, resulting in high-fidelity 21-nt siRNA production. This study sheds light on the molecular mechanism by which Dicer-2 produces 21-nt siRNAs with a remarkably high fidelity for efficient RNA silencing. PMID:27872309

Efficient photoconductive terahertz detector with all-dielectric optical metasurface

NASA Astrophysics Data System (ADS)

Mitrofanov, Oleg; Siday, Thomas; Thompson, Robert J.; Luk, Ting Shan; Brener, Igal; Reno, John L.

2018-05-01

We designed an optically thin photoconductive channel as an all-dielectric metasurface comprising an array of low-temperature grown GaAs nanobeams and a sub-surface distributed Bragg reflector. The metasurface exhibited enhanced optical absorption, and it was integrated into a photoconductive THz detector, which showed high efficiency and sensitivity as a result. The detector produced photocurrents over one order of magnitude higher compared to a similar detector with an unstructured surface with only 0.5 mW of optical excitation while exhibiting high dark resistance required for low-noise detection in THz time-domain spectroscopy and imaging. At that level of optical excitation, the metasurface detector showed a high signal to noise ratio of 106. The detector showed saturation above that level.

Coupling chemical and biological catalysis: a flexible paradigm for producing biobased chemicals.

PubMed

Schwartz, Thomas J; Shanks, Brent H; Dumesic, James A

2016-04-01

Advances in metabolic engineering have allowed for the development of new biological catalysts capable of selectively de-functionalizing biomass to yield platform molecules that can be upgraded to biobased chemicals using high efficiency continuous processing allowed by heterogeneous chemical catalysis. Coupling these disciplines overcomes the difficulties of selectively activating COH bonds by heterogeneous chemical catalysis and producing petroleum analogues by biological catalysis. We show that carboxylic acids, pyrones, and alcohols are highly flexible platforms that can be used to produce biobased chemicals by this approach. More generally, we suggest that molecules with three distinct functionalities may represent a practical upper limit on the extent of functionality present in the platform molecules that serve as the bridge between biological and chemical catalysis. Copyright © 2016 Elsevier Ltd. All rights reserved.

High-Performance Lithium-Oxygen Battery Electrolyte Derived from Optimum Combination of Solvent and Lithium Salt.

PubMed

Ahn, Su Mi; Suk, Jungdon; Kim, Do Youb; Kang, Yongku; Kim, Hwan Kyu; Kim, Dong Wook

2017-10-01

To fabricate a sustainable lithium-oxygen (Li-O 2 ) battery, it is crucial to identify an optimum electrolyte. Herein, it is found that tetramethylene sulfone (TMS) and lithium nitrate (LiNO 3 ) form the optimum electrolyte, which greatly reduces the overpotential at charge, exhibits superior oxygen efficiency, and allows stable cycling for 100 cycles. Linear sweep voltammetry (LSV) and differential electrochemical mass spectrometry (DEMS) analyses reveal that neat TMS is stable to oxidative decomposition and exhibit good compatibility with a lithium metal. But, when TMS is combined with typical lithium salts, its performance is far from satisfactory. However, the TMS electrolyte containing LiNO 3 exhibits a very low overpotential, which minimizes the side reactions and shows high oxygen efficiency. LSV-DEMS study confirms that the TMS-LiNO 3 electrolyte efficiently produces NO 2 - , which initiates a redox shuttle reaction. Interestingly, this NO 2 - /NO 2 redox reaction derived from the LiNO 3 salt is not very effective in solvents other than TMS. Compared with other common Li-O 2 solvents, TMS seems optimum solvent for the efficient use of LiNO 3 salt. Good compatibility with lithium metal, high dielectric constant, and low donicity of TMS are considered to be highly favorable to an efficient NO 2 - /NO 2 redox reaction, which results in a high-performance Li-O 2 battery.

Characterization of Catalase from Psychrotolerant Psychrobacter piscatorii T-3 Exhibiting High Catalase Activity

PubMed Central

Kimoto, Hideyuki; Yoshimune, Kazuaki; Matsuyma, Hidetoshi; Yumoto, Isao

2012-01-01

A psychrotolerant bacterium, strain T-3 (identified as Psychrobacter piscatorii), that exhibited an extraordinarily high catalase activity was isolated from the drain pool of a plant that uses H2O2 as a bleaching agent. Its cell extract exhibited a catalase activity (19,700 U·mg protein−1) that was higher than that of Micrococcus luteus used for industrial catalase production. Catalase was approximately 10% of the total proteins in the cell extract of the strain. The catalase (PktA) was purified homogeneously by only two purification steps, anion exchange and hydrophobic chromatographies. The purified catalase exhibited higher catalytic efficiency and higher sensitivity of activity at high temperatures than M. luteus catalase. The deduced amino acid sequence showed the highest homology with catalase of Psycrobacter cryohalolentis, a psychrotolelant bacterium obtained from Siberian permafrost. These findings suggest that the characteristics of the PktA molecule reflected the taxonomic relationship of the isolate as well as the environmental conditions (low temperatures and high concentrations of H2O2) under which the bacterium survives. Strain T-3 efficiently produces a catalase (PktA) at a higher rate than Exiguobacterium oxidotolerans, which produces a very strong activity of catalase (EktA) at a moderate rate, in order to adapt to high concentration of H2O2. PMID:22408420

Fabrication of photovoltaic laser energy converterby MBE

NASA Technical Reports Server (NTRS)

Lu, Hamilton; Wang, Scott; Chan, W. S.

1993-01-01

A laser-energy converter, fabricated by molecular beam epitaxy (MBE), was developed. This converter is a stack of vertical p-n junctions connected in series by low-resistivity, lattice matched CoSi2 layers to achieve a high conversion efficiency. Special high-temperature electron-beam (e-beam) sources were developed especially for the MBE growth of the junctions and CoSi2 layers. Making use of the small (greater than 1.2 percent) lattice mismatch between CoSi2 and Si layers, high-quality and pinhole-free epilayers were achieved, providing a capability of fabricating all the junctions and connecting layers as a single growth process with one pumpdown. Well-defined multiple p-n junctions connected by CoSi2 layers were accomplished by employing a low growth temperature (greater than 700 C) and a low growth rate (less than 0.5 microns/hour). Producing negligible interdiffusion, the low growth temperature and rate also produced negligible pinholes in the CoSi2 layers. For the first time, a stack of three p-n junctions connected by two 10(exp -5) Ohm-cm CoSi2 layers was achieved, meeting the high conversion efficiency requirement. This process can now be optimized for high growth rate to form a practical converter with 10 p-n junctions in the stack.

Hybrid carbon nanoparticles modified core-shell silica: a high efficiency carbon-based phase for hydrophilic interaction liquid chromatography.

PubMed

Ibrahim, Mohammed E A; Wahab, M Farooq; Lucy, Charles A

2014-04-11

Hydrophilic interaction liquid chromatography (HILIC) is a fast growing separation technique for hydrophilic and polar analytes. In this work, we combine the unique selectivity of carbon surfaces with the high efficiency of core-shell silica. First, 5 μm core-shell silica is electrostatically coated with 105 nm cationic latex bearing quaternary ammonium groups. Then 50 nm anionic carbon nanoparticles are anchored onto the surface of the latex coated core-shell silica particles to produce a hybrid carbon-silica phase. The hybrid phase shows different selectivity than ten previously classified HILIC column chemistries and 36 stationary phases. The hybrid HILIC phase has shape selectivity for positional isomeric pairs (phthalic/isophthalic and 1-naphthoic/2-naphthoic acids). Fast and high efficiency HILIC separations of biologically important carboxylates, phenols and pharmaceuticals are reported with efficiencies up to 85,000 plates m(-1). Reduced plate height of 1.9 (95,000 plates m(-1)) can be achieved. The hybrid phase is stable for at least 3 months of usage and storage under typical HILIC eluents. Copyright © 2014 Elsevier B.V. All rights reserved.

Diesel NO(x) aftertreatment by combined process using temperature swing adsorption, NO(x) reduction by nonthermal plasma, and NO(x) recirculation: improvement of the recirculation process.

PubMed

Yoshida, Keiichiro; Kuwahara, Takuya; Kuroki, Tomoyuki; Okubo, Masaaki

2012-09-15

NO(x) emitted from a stationary diesel engine generator was treated with a hybrid system comprising NO(x) reduction by nonthermal plasma (NTP) and temperature swing adsorption (TSA) driven by engine waste heat. TSA produces a low-volume gas mixture of N(2) and highly concentrated NO(x), which is effectively reduced by NTP treatment. Improved treatment performance and efficiency are achieved by re-injecting the NTP-treated gas mixture into the engine intake. The system comprises two switchable adsorption chambers; the operation of this system was simulated by using a one-chamber system. The maximum energy efficiency for NO(x) treatment is 200 g(NO(2))/kWh. The respective contributions of NTP and injection of N(2) and NO(x) to the performance were theoretically analyzed. The analysis predicts that high energy efficiency and high NO(x)-removal efficiency can be simultaneously achieved with this system but miniaturization of the adsorption chambers will be a challenge. Copyright © 2012 Elsevier B.V. All rights reserved.

Economic and environmental evaluation of compressed-air cars

NASA Astrophysics Data System (ADS)

Creutzig, Felix; Papson, Andrew; Schipper, Lee; Kammen, Daniel M.

2009-10-01

Climate change and energy security require a reduction in travel demand, a modal shift, and technological innovation in the transport sector. Through a series of press releases and demonstrations, a car using energy stored in compressed air produced by a compressor has been suggested as an environmentally friendly vehicle of the future. We analyze the thermodynamic efficiency of a compressed-air car powered by a pneumatic engine and consider the merits of compressed air versus chemical storage of potential energy. Even under highly optimistic assumptions the compressed-air car is significantly less efficient than a battery electric vehicle and produces more greenhouse gas emissions than a conventional gas-powered car with a coal intensive power mix. However, a pneumatic-combustion hybrid is technologically feasible, inexpensive and could eventually compete with hybrid electric vehicles.

Independent Power Generation in a Modern Electrical Substation Based on Thermoelectric Technology

NASA Astrophysics Data System (ADS)

Li, Z. M.; Zhao, Y. Q.; Liu, W.; Wei, B.; Qiu, M.; Lai, X. K.

2017-05-01

Because of many types of electrical equipment with high power in substations, the potentiality of energy conservation is quite large. From this viewpoint, thermoelectric materials may be chosen to produce electrical energy using the waste heat produced in substations. Hence, a thermoelectric generation system which can recycle the waste heat from electric transformers was proposed to improve the energy efficiency and reduce the burden of the oil cooling system. An experimental prototype was fabricated to perform the experiment and to verify the feasibility. The experimental results showed that the output power could achieve 16 W from waste heat of 900 W, and that the power conversion efficiency was approximately 1.8%. Therefore, power generation is feasible by using the waste heat from the transformers based on thermoelectric technology.

Experimental demonstration of a compact epithermal neutron source based on a high power laser

NASA Astrophysics Data System (ADS)

Mirfayzi, S. R.; Alejo, A.; Ahmed, H.; Raspino, D.; Ansell, S.; Wilson, L. A.; Armstrong, C.; Butler, N. M. H.; Clarke, R. J.; Higginson, A.; Kelleher, J.; Murphy, C. D.; Notley, M.; Rusby, D. R.; Schooneveld, E.; Borghesi, M.; McKenna, P.; Rhodes, N. J.; Neely, D.; Brenner, C. M.; Kar, S.

2017-07-01

Epithermal neutrons from pulsed-spallation sources have revolutionised neutron science allowing scientists to acquire new insight into the structure and properties of matter. Here, we demonstrate that laser driven fast (˜MeV) neutrons can be efficiently moderated to epithermal energies with intrinsically short burst durations. In a proof-of-principle experiment using a 100 TW laser, a significant epithermal neutron flux of the order of 105 n/sr/pulse in the energy range of 0.5-300 eV was measured, produced by a compact moderator deployed downstream of the laser-driven fast neutron source. The moderator used in the campaign was specifically designed, by the help of MCNPX simulations, for an efficient and directional moderation of the fast neutron spectrum produced by a laser driven source.

Advancing metabolic engineering through systems biology of industrial microorganisms.

PubMed

Dai, Zongjie; Nielsen, Jens

2015-12-01

Development of sustainable processes to produce bio-based compounds is necessary due to the severe environmental problems caused by the use of fossil resources. Metabolic engineering can facilitate the development of highly efficient cell factories to produce these compounds from renewable resources. The objective of systems biology is to gain a comprehensive and quantitative understanding of living cells and can hereby enhance our ability to characterize and predict cellular behavior. Systems biology of industrial microorganisms is therefore valuable for metabolic engineering. Here we review the application of systems biology tools for the identification of metabolic engineering targets which may lead to reduced development time for efficient cell factories. Finally, we present some perspectives of systems biology for advancing metabolic engineering further. Copyright © 2015 Elsevier Ltd. All rights reserved.

RF pulse compression for future linear colliders

NASA Astrophysics Data System (ADS)

Wilson, Perry B.

1995-07-01

Future (nonsuperconducting) linear colliders will require very high values of peak rf power per meter of accelerating structure. The role of rf pulse compression in producing this power is examined within the context of overall rf system design for three future colliders at energies of 1.0-1.5 TeV, 5 TeV, and 25 TeV. In order to keep the average AC input power and the length of the accelerator within reasonable limits, a collider in the 1.0-1.5 TeV energy range will probably be built at an x-band rf frequency, and will require a peak power on the order of 150-200 MW per meter of accelerating structure. A 5 TeV collider at 34 GHz with a reasonable length (35 km) and AC input power (225 MW) would require about 550 MW per meter of structure. Two-beam accelerators can achieve peak powers of this order by applying dc pulse compression techniques (induction linac modules) to produce the drive beam. Klystron-driven colliders achieve high peak power by a combination of dc pulse compression (modulators) and rf pulse compression, with about the same overall rf system efficiency (30-40%) as a two-beam collider. A high gain (6.8) three-stage binary pulse compression system with high efficiency (80%) is described, which (compared to a SLED-II system) can be used to reduce the klystron peak power by about a factor of two, or alternatively, to cut the number of klystrons in half for a 1.0-1.5 TeV x-band collider. For a 5 TeV klystron-driven collider, a high gain, high efficiency rf pulse compression system is essential.

Lunar Oxygen Production and Metals Extraction Using Ionic Liquids

NASA Technical Reports Server (NTRS)

Marone, Matthew; Paley, Mark Steven; Donovan, David N.; Karr, Laurel J.

2009-01-01

Initial results indicate that ionic liquids are promising media for the extraction of oxygen from lunar regolith. IL acid systems can solubilize regolith and produce water with high efficiency. IL electrolytes are effective for water electrolysis, and the spent IL acid media are capable of regeneration.

Thin film polymeric gel electrolytes

DOEpatents

Derzon, Dora K.; Arnold, Jr., Charles; Delnick, Frank M.

1996-01-01

Novel hybrid thin film electrolyte, based on an organonitrile solvent system, which are compositionally stable, environmentally safe, can be produced efficiently in large quantity and which, because of their high conductivities .apprxeq.10.sup.-3 .OMEGA..sup.-1 cm.sup.-1 are useful as electrolytes for rechargeable lithium batteries.

The effective photoinduction of Haematococcus pluvialis for accumulating astaxanthin with attached cultivation.

PubMed

Wan, Minxi; Hou, Dongmei; Li, Yuanguang; Fan, Jianhua; Huang, Jianke; Liang, Songtao; Wang, Weiliang; Pan, Ronghua; Wang, Jun; Li, Shulan

2014-07-01

As the optimal source of astaxanthin, Haematococcus pluvialis was cultured for commercial production of astaxanthin through two continuous phases: cell growth and astaxanthin induction. In this study, the efficiency of an attached system for producing astaxanthin from H. pluvialis was investigated and compared to that of the suspended system (bubble column bioreactor) under various conditions. Results showed that this attached system is more suitable for photoinduction of H. pluvialis than the suspended bioreactor. Under the optimal conditions, the astaxanthin productivity of the attached system was 65.8 mg m(-2)d(-1) and 2.4-fold of that in the suspended system. This attached approach also offers other advantages over suspended systems, such as, producing astaxanthin under a wide range of light intensities and temperatures, saving water, ease to harvest cells, resisting contamination. Therefore, the attached approach can be considered an economical, environmentally friendly and highly-efficient technology for producing astaxanthin from H. pluvialis. Copyright © 2014 Elsevier Ltd. All rights reserved.

Summary of Recent Hybrid Torpedo Powerplant Studies

DTIC Science & Technology

2007-12-01

engine (such as the one used in SCEPS), a generic open-cycle expander engine that operates on a mixture of combustion products, a Brayton cycle engine ...difficult to produce an efficient engine that operates at a high backpressure . This particular value was chosen because it was used in a study of various... Effect of Design High Speed .........................................................................13 Figure 4: Hybrid vs. Conventional Torpedo Range

Laser ion source for multi-nucleon transfer reaction products

NASA Astrophysics Data System (ADS)

Hirayama, Y.; Watanabe, Y. X.; Imai, N.; Ishiyama, H.; Jeong, S. C.; Miyatake, H.; Oyaizu, M.; Kimura, S.; Mukai, M.; Kim, Y. H.; Sonoda, T.; Wada, M.; Huyse, M.; Kudryavtsev, Yu.; Van Duppen, P.

2015-06-01

We have developed a laser ion source for the target-like fragments (TLFs) produced in multi-nucleon transfer (MNT) reactions. The operation principle of the source is based on the in-gas laser ionization and spectroscopy (IGLIS) approach. In the source TLFs are thermalized and neutralized in high pressure and high purity argon gas, and are extracted after being selectively re-ionized in a multi-step laser resonance ionization process. The laser ion source has been implemented at the KEK Isotope Separation System (KISS) for β-decay spectroscopy of neutron-rich isotopes with N = 126 of nuclear astrophysical interest. The simulations of gas flow and ion-beam optics have been performed to optimize the gas cell for efficient thermalization and fast transporting the TLFs, and the mass-separator for efficient transport with high mass-resolving power, respectively. To confirm the performances expected at the design stage, off-line experiments have been performed by using 56Fe atoms evaporated from a filament in the gas cell. The gas-transport time of 230 ms in the argon cell and the measured KISS mass-resolving power of 900 are consistent with the designed values. The high purity of the gas-cell system, which is extremely important for efficient and highly-selective production of laser ions, was achieved and confirmed from the mass distribution of the extracted ions. After the off-line tests, on-line experiments were conducted by directly injecting energetic 56Fe beam into the gas cell. After thermalization of the injected 56Fe beam, laser-produced singly-charged 56Fe+ ions were extracted. The extraction efficiency and selectivity of the gas cell in the presence of plasma induced by 56Fe beam injection as well as the time profile of the extracted ions were investigated; extraction efficiency of 0.25%, a beam purity of >99% and an extraction time of 270 ms. It has been confirmed that the performance of the KISS laser ion source is satisfactory to start the measurements of lifetimes of the β-decayed nuclei with N = 126 .

TM-30 Guidance

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

Royer, Michael P.

Minimum color quality standards are necessary, because the light sources most efficient at producing lumens are impractical for use in architectural lighting due to poor color rendition. Thus, accurate measures of color rendition and accompanying performance criteria are essential for helping technology developers and users balance tradeoffs between energy efficiency and lighting quality. Setting higher color-rendition criteria while maintaining use of CRI (e.g., CRI ≥ 90) may filter out some unacceptable light sources, but also filters out many highly desirable light sources and requires a greater tradeoff with energy efficiency. In contrast, specifying color rendition using TM-30 Rf, Rg, andmore » Rcs,h1 has been shown to be effective for differentiating desirable sources while maintaining flexibility for technology development and energy efficiency.« less

Pure climb creep mechanism drives flow in Earth’s lower mantle

PubMed Central

Boioli, Francesca; Carrez, Philippe; Cordier, Patrick; Devincre, Benoit; Gouriet, Karine; Hirel, Pierre; Kraych, Antoine; Ritterbex, Sebastian

2017-01-01

At high pressure prevailing in the lower mantle, lattice friction opposed to dislocation glide becomes very high, as reported in recent experimental and theoretical studies. We examine the consequences of this high resistance to plastic shear exhibited by ringwoodite and bridgmanite on creep mechanisms under mantle conditions. To evaluate the consequences of this effect, we model dislocation creep by dislocation dynamics. The calculation yields to an original dominant creep behavior for lower mantle silicates where strain is produced by dislocation climb, which is very different from what can be activated under high stresses under laboratory conditions. This mechanism, named pure climb creep, is grain-size–insensitive and produces no crystal preferred orientation. In comparison to the previous considered diffusion creep mechanism, it is also a more efficient strain-producing mechanism for grain sizes larger than ca. 0.1 mm. The specificities of pure climb creep well match the seismic anisotropy observed of Earth’s lower mantle. PMID:28345037

Roles of coercivity and remanent flux density of permanent magnet in interior permanent magnet synchronous motor (IPMSM) performance for electric vehicle applications

NASA Astrophysics Data System (ADS)

Won, Hoyun; Hong, Yang-Ki; Lee, Woncheol; Choi, Minyeong

2018-05-01

We used four rotor topologies of an interior permanent magnet synchronous motor (IPMSM) to investigate the effects of remanent flux density (Br) and coercivity (Hc) of permanent magnet on motor performance. Commercial strontium hexaferrite (SrFe12O19: energy product, (BH)max, of 4.62 MGOe) and Nd-Fe-B ((BH)max of 38.2 MGOe) magnets were used for the rotor designs. The same machine specifications and magnet volume keep constant, while the Hc and Br vary to calculate torque and energy efficiency with the finite-element analysis. A combination of high Hc and low Br more effectively increased maximum torque of IPMSM when the hexaferrite magnet was used. For Nd-Fe-B magnet, the same combination did not affect maximum torque, but increased energy efficiency at high speed. Therefore, the Hc value of a permanent magnet is more effective than the Br in producing high maximum torque for SrM-magnet based IPMSM and high energy efficiency at high speed for Nd-Fe-B magnet based IPMSM.

Formation of ultra Si/Ti nano thin film for enhancing silicon solar cell efficiency

NASA Astrophysics Data System (ADS)

Adam, T.; Dhahi, T. S.; Mohammed, M.; Al-Hajj, A. M.; Hashim, U.

2017-10-01

An alternative electrical source has l has become the major quest of every researchers due to it numerous advantages and applications of power supply and as electronic devices are becoming more and more portable. A highly efficient power supply is become inevitable. Thus. in this study, present ultrasonic based assisted fabrication of electrochemical silicon-Titanium nano thin film by in-house simple technique, uniformly silicon Nano film was fabricated and etched with HF (40%): C2H5OH (99%):1:1, < 20 nm pore diameter of silicon was fabricated. The surface and morphology reveal that the method produce uniform nano silicon porous layer with smaller silicon pores with high etching efficiency. The silicon-Titanium integrated nano porous exhibited excellent observation properties with low reflection index ~ 1.1 compared to silicon alone thin film.

Factors affecting beef cattle producer perspectives on feed efficiency.

PubMed

Wulfhorst, J D; Ahola, J K; Kane, S L; Keenan, L D; Hill, R A

2010-11-01

To establish the basis for implementation of a producer education program, a social assessment of the willingness and barriers to adoption of a measure of feed efficiency in beef cattle [residual feed intake (RFI)] was conducted. A 35-question mailed survey was sent to 1,888 producers acquired from the stratified random sample of the Idaho Cattle Association member list (n = 488), Red Angus Association of America member list (n = 2,208), and Red Angus Association of America bull buyer list (n = 5,325). The adjusted response rate for the survey was 49.9%. Of the survey respondents, 58.7% were commercial cow/calf producers and 41.3% were seedstock producers or operated a combination seedstock/commercial operation. Commercial operations had an average of 223 ± 17 cows and 13 ± 3 bulls, whereas seedstock herds (including combination herds) had slightly fewer cows (206 ± 24) and more bulls (23 ± 6). Both commercial and seedstock operators indicated that calving ease/birth weight was the most important trait used to evaluate genetic merit of breeding bulls. Only 3.8 and 4.8% of commercial and seedstock producers indicated that feed efficiency was the most important characteristic used for bull selection. Binary logistic regression models were used to predict willingness of seedstock producers to begin collecting data for the calculation of RFI on their bulls, or to predict willingness of commercial producers to begin selecting bulls based on RFI data. In response, 49.1% of commercial producers and 43.6% of seedstock producers indicated they were willing to adopt RFI as a measure of feed efficiency. These data indicate that feed efficiency was one of the traits that producers consider important; those who perceive feed efficiency as important tended to be actively involved in data collection on their herds, underpinning the notion that objective assessment was valued and used by some. Additional data collection in a future social assessment will continue to elaborate the proportion of producers who perceive feed efficiency as an increasingly important decision and management tool for beef production.

A practical and improved synthesis of (3S,5S)-3-[(tert-butyloxycarbonyl)methyl]- 5-[(methanesulfonyloxy)methyl]-2- pyrrolidinone.

PubMed

Yee, Nathan K; Dong, Yong; Kapadia, Suresh R; Song, Jinhua J

2002-11-29

A practical and improved synthesis of (3S,5S)-3-[(tert-butyloxycarbonyl)methyl]-5-[(methanesulfonyloxy)methyl]-2-pyrrolidinone (1) is described. The key transformations involve a highly efficient reaction sequence consisting of ethoxycarbonylation, alkylation, hydrolysis, and decarboxylation to produce compound 10. The process described herein is practical, robust, and cost-effective, and it has been successfully implemented in a pilot plant to produce a multikilogram quantity of mesylate 1.

High Efficiency Solar Thermochemical Reactor for Hydrogen Production.

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

McDaniel, Anthony H.

2017-09-30

This research and development project is focused on the advancement of a technology that produces hydrogen at a cost that is competitive with fossil-based fuels for transportation. A twostep, solar-driven WS thermochemical cycle is theoretically capable of achieving an STH conversion ratio that exceeds the DOE target of 26% at a scale large enough to support an industrialized economy [1]. The challenge is to transition this technology from the laboratory to the marketplace and produce hydrogen at a cost that meets or exceeds DOE targets.

Use of bacterial acc deaminase to increase oil (especially poly aromatic hydrocarbons) phytoremediation efficiency for maize (zea mays) seedlings.

PubMed

Rezvani Borujeni, Samira; Khavazi, Kazem; Asgharzadeh, Ahmad; Rezvani Borujeni, Iraj

2018-04-16

Oil presence in soil, as a stressor, reduces phytoremediation efficiency through an increase in the plant stress ethylene. Bacterial 1-aminocyclopropane-1-carboxylic acid (ACC) deaminase, as a plant stress ethylene reducer, was employed to increase oil phytoremediation efficiency. For this purpose, the ability of ACC deaminase-producing Pseudomonas strains to grow in oil-polluted culture media and withstand various concentrations of oil and also their ability to reduce plant stress ethylene and enhance some growth characteristics of maize and finally their effects on increasing phytoremediation efficiency of poly aromatic hydrocarbons (PAHs) in soil were investigated. Based on the results, of tested strains just P9 and P12 were able to perform oil degradation. Increasing oil concentration from 0 to 10% augmented these two strains population, 15.7% and 12.9%, respectively. The maximum increase in maize growth was observed in presence of P12 strain. Results of high-performance liquid chromatography (HPLC) revealed that PAHs phytoremediation efficiency was higher for inoculated seeds than uninoculated. The highest plant growth and PAHs removal percentage (74.9%) from oil-polluted soil was observed in maize inoculated with P12. These results indicate the significance of ACC deaminase producing bacteria in alleviation of plant stress ethylene in oil-polluted soils and increasing phytoremediation efficiency of such soils.

Overexpression of smORF YNR034W-A/EGO4 in Saccharomyces cerevisiae increases the fermentative efficiency of Agave tequilana Weber must.

PubMed

Vargas-Maya, Naurú Idalia; González-Hernández, Gloria Angélica; Padilla-Guerrero, Israel Enrique; Torres-Guzmán, Juan Carlos

2017-01-01

Fermentative processes are widely used to produce food, beverages and biofuels. Saccharomyces cerevisiae is an efficient ethanol-producing microorganism. However, a concentration of high ethanol and other metabolites can affect yeast viability and decrease the ethanol yield. Many studies have focused on improving the fermentative efficiency, mostly through the genetic engineering of genes that have a direct impact on specific metabolic pathways. In the present study, we characterized a small open reading frame encoding a protein with an unknown function and biological role termed YNR034W-A. We analyzed the expression profile of the YNR034W-A gene during growth and glucose treatment, finding that it is expressed during the diauxic shift and stationary phase and is negatively regulated by glucose. We overexpressed the YNR034W-A gene in the BY4741 laboratory strain and a wild-type yeast strain (AR5) isolated during the Tequila fermentation process. Transformant derivatives of the AR5 strain showed an improved fermentative efficiency during fermentation of Agave tequilana Weber juice. We suggest that the improved fermentative efficiency is the result of a higher stress tolerance response in the YNR034W-A overexpressing transformant.

Chemically modified biochar produced from conocarpus waste increases NO3 removal from aqueous solutions.

PubMed

Usman, Adel R A; Ahmad, Mahtab; El-Mahrouky, Mohamed; Al-Omran, Abdulrasoul; Ok, Yong Sik; Sallam, Abdelazeem Sh; El-Naggar, Ahmed H; Al-Wabel, Mohammad I

2016-04-01

Biochar has emerged as a universal sorbent for the removal of contaminants from water and soil. However, its efficiency is lower than that of commercially available sorbents. Engineering biochar by chemical modification may improve its sorption efficiency. In this study, conocarpus green waste was chemically modified with magnesium and iron oxides and then subjected to thermal pyrolysis to produce biochar. These chemically modified biochars were tested for NO3 removal efficiency from aqueous solutions in batch sorption isothermal and kinetic experiments. The results revealed that MgO-biochar outperformed other biochars with a maximum NO3 sorption capacity of 45.36 mmol kg(-1) predicted by the Langmuir sorption model. The kinetics data were well described by the Type 1 pseudo-second-order model, indicating chemisorption as the dominating mechanism of NO3 sorption onto biochars. Greater efficiency of MgO-biochar was related to its high specific surface area (391.8 m(2) g(-1)) and formation of strong ionic complexes with NO3. At an initial pH of 2, more than 89 % NO3 removal efficiency was observed for all of the biochars. We conclude that chemical modification can alter the surface chemistry of biochar, thereby leading to enhanced sorption capacity compared with simple biochar.

The efficiency of parameter estimation of latent path analysis using summated rating scale (SRS) and method of successive interval (MSI) for transformation of score to scale

NASA Astrophysics Data System (ADS)

Solimun, Fernandes, Adji Achmad Rinaldo; Arisoesilaningsih, Endang

2017-12-01

Research in various fields generally investigates systems and involves latent variables. One method to analyze the model representing the system is path analysis. The data of latent variables measured using questionnaires by applying attitude scale model yields data in the form of score, before analyzed should be transformation so that it becomes data of scale. Path coefficient, is parameter estimator, calculated from scale data using method of successive interval (MSI) and summated rating scale (SRS). In this research will be identifying which data transformation method is better. Path coefficients have smaller varieties are said to be more efficient. The transformation method that produces scaled data and used in path analysis capable of producing path coefficients (parameter estimators) with smaller varieties is said to be better. The result of analysis using real data shows that on the influence of Attitude variable to Intention Entrepreneurship, has relative efficiency (ER) = 1, where it shows that the result of analysis using data transformation of MSI and SRS as efficient. On the other hand, for simulation data, at high correlation between items (0.7-0.9), MSI method is more efficient 1.3 times better than SRS method.

Perceptual load corresponds with factors known to influence visual search

PubMed Central

Roper, Zachary J. J.; Cosman, Joshua D.; Vecera, Shaun P.

2014-01-01

One account of the early versus late selection debate in attention proposes that perceptual load determines the locus of selection. Attention selects stimuli at a late processing level under low-load conditions but selects stimuli at an early level under high-load conditions. Despite the successes of perceptual load theory, a non-circular definition of perceptual load remains elusive. We investigated the factors that influence perceptual load by using manipulations that have been studied extensively in visual search, namely target-distractor similarity and distractor-distractor similarity. Consistent with previous work, search was most efficient when targets and distractors were dissimilar and the displays contained homogeneous distractors; search became less efficient when target-distractor similarity increased irrespective of display heterogeneity. Importantly, we used these same stimuli in a typical perceptual load task that measured attentional spill-over to a task-irrelevant flanker. We found a strong correspondence between search efficiency and perceptual load; stimuli that generated efficient searches produced flanker interference effects, suggesting that such displays involved low perceptual load. Flanker interference effects were reduced in displays that produced less efficient searches. Furthermore, our results demonstrate that search difficulty, as measured by search intercept, has little bearing on perceptual load. These results suggest that perceptual load might be defined in part by well-characterized, continuous factors that influence visual search. PMID:23398258

Membraneless laminar flow cell for electrocatalytic CO2 reduction with liquid product separation

NASA Astrophysics Data System (ADS)

Monroe, Morgan M.; Lobaccaro, Peter; Lum, Yanwei; Ager, Joel W.

2017-04-01

The production of liquid fuel products via electrochemical reduction of CO2 is a potential path to produce sustainable fuels. However, to be practical, a separation strategy is required to isolate the fuel-containing electrolyte produced at the cathode from the anode and also prevent the oxidation products (i.e. O2) from reaching the cathode. Ion-conducting membranes have been applied in CO2 reduction reactors to achieve this separation, but they represent an efficiency loss and can be permeable to some product species. An alternative membraneless approach is developed here to maintain product separation through the use of a laminar flow cell. Computational modelling shows that near-unity separation efficiencies are possible at current densities achievable now with metal cathodes via optimization of the spacing between the electrodes and the electrolyte flow rate. Laminar flow reactor prototypes were fabricated with a range of channel widths by 3D printing. CO2 reduction to formic acid on Sn electrodes was used as the liquid product forming reaction, and the separation efficiency for the dissolved product was evaluated with high performance liquid chromatography. Trends in product separation efficiency with channel width and flow rate were in qualitative agreement with the model, but the separation efficiency was lower, with a maximum value of 90% achieved.

Development of real-time PCR methods to quantify patulin-producing molds in food products.

PubMed

Rodríguez, Alicia; Luque, M Isabel; Andrade, María J; Rodríguez, Mar; Asensio, Miguel A; Córdoba, Juan J

2011-09-01

Patulin is a mycotoxin produced by different Penicillium and Aspergillus strains isolated from food products. To improve food safety, the presence of patulin-producing molds in foods should be quantified. In the present work, two real-time (RTi) PCR protocols based on SYBR Green and TaqMan were developed. Thirty four patulin producers and 28 non-producers strains belonging to different species usually reported in food products were used. The patulin production was tested by mycellar electrokinetic capillary electrophoresis (MECE) and high-pressure liquid chromatography-mass spectrometry (HPLC-MS). A primer pair F-idhtrb/R-idhtrb and the probe IDHprobe were designed from the isoepoxydon dehydrogenase (idh) gene, involved in patulin biosynthesis. The functionality of the developed method was demonstrated by the high linear relationship of the standard curves constructed with the idh gene copy number and Ct values for the different patulin producers tested. The ability to quantify patulin producers of the developed SYBR Green and TaqMan assays in artificially inoculated food samples was successful, with a minimum threshold of 10 conidia g(-1) per reaction. The developed methods quantified with high efficiency fungal load in foods. These RTi-PCR protocols, are proposed to be used to quantify patulin-producing molds in food products and to prevent patulin from entering the food chain. Copyright © 2011 Elsevier Ltd. All rights reserved.

Processes for producing low cost, high efficiency silicon solar cells

DOEpatents

Rohatgi, Ajeet; Doshi, Parag; Tate, John Keith; Mejia, Jose; Chen, Zhizhang

1998-06-16

Processes which utilize rapid thermal processing (RTP) are provided for inexpensively producing high efficiency silicon solar cells. The RTP processes preserve minority carrier bulk lifetime .tau. and permit selective adjustment of the depth of the diffused regions, including emitter and back surface field (bsf), within the silicon substrate. In a first RTP process, an RTP step is utilized to simultaneously diffuse phosphorus and aluminum into the front and back surfaces, respectively, of a silicon substrate. Moreover, an in situ controlled cooling procedure preserves the carrier bulk lifetime .tau. and permits selective adjustment of the depth of the diffused regions. In a second RTP process, both simultaneous diffusion of the phosphorus and aluminum as well as annealing of the front and back contacts are accomplished during the RTP step. In a third RTP process, the RTP step accomplishes simultaneous diffusion of the phosphorus and aluminum, annealing of the contacts, and annealing of a double-layer antireflection/passivation coating SiN/SiO.sub.x. In a fourth RTP process, the process of applying front and back contacts is broken up into two separate respective steps, which enhances the efficiency of the cells, at a slight time expense. In a fifth RTP process, a second RTP step is utilized to fire and adhere the screen printed or evaporated contacts to the structure.

High-Temperature Particulate Matter Filtration with Resilient Yttria-Stabilized ZrO2 Nanofiber Sponge.

PubMed

Wang, Haolun; Lin, Sen; Yang, Shen; Yang, Xudong; Song, Jianan; Wang, Dong; Wang, Haiyang; Liu, Zhenglian; Li, Bo; Fang, Minghao; Wang, Ning; Wu, Hui

2018-05-01

Particulate matter (PM) is a major air pollutant in many regions, jeopardizing ecosystems and public health. Filtration at pollutant source is one of the most important ways to protect the environment, however, considering the high-temperature exhaust gas emissions, effective removal of PM and related pollutants from their sources remains a major challenge. In this study, a resilient, heat-resisting, and high-efficiency PM filter based on yttria-stabilized ZrO 2 (YSZ) nanofiber sponge produced with a scalable solution blow spinning process is reported. The porous 3D sponge composed of YSZ nanofibers is lightweight (density of 20 mg cm -3 ) and resilient at both room temperature and high temperatures. At room-temperature conditions, the YSZ nanofiber sponge exhibits 99.4% filtration efficiency for aerosol particles with size in the range of 20-600 nm, associated with a low pressure drop of only 57 Pa under an airflow velocity of 4.8 cm s -1 . At a high temperature of 750 °C, the ceramic sponge maintains a high filtration efficiency of 99.97% for PM 0.3-2.5 under a high airflow velocity of 10 cm s -1 . A practical vehicle exhaust filter to capture particles with filtration efficiency of >98.3% is also assembled. Hence, the YSZ nanofiber sponge has enormous potential to be applied in industry. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Genome-wide association of porcine lung lesions using DNA pooling

USDA-ARS?s Scientific Manuscript database

Respiratory disease in swine is a primary health concern for producers. Pleuropneumonia and enzootic pneumonia occur at a high incidence on most farms and have a negative effect on feed efficiency, growth, and animal welfare. Mycoplasma pneumonia is one of the most important because it increases sus...

NOx reduction by electron beam-produced nitrogen atom injection

DOEpatents

Penetrante, Bernardino M.

2002-01-01

Deactivated atomic nitrogen generated by an electron beam from a gas stream containing more than 99% N.sub.2 is injected at low temperatures into an engine exhaust to reduce NOx emissions. High NOx reduction efficiency is achieved with compact electron beam devices without use of a catalyst.

Esterification pretreatment of free fatty acid in biodiesel production, from laboratory to industry

EPA Science Inventory

Making biodiesel from recycled oils and fats has expanded from household to commercial operations as a sustainable way to produce alternative energy and reduce waste. However, the high free fatty acids (FFA) content in waste cooking oils can greatly reduce the efficiency of the ...

Method of preparing thin film polymeric gel electrolytes

DOEpatents

Derzon, Dora K.; Arnold, Jr., Charles

1997-01-01

Novel hybrid thin film electrolyte, based on an organonitrile solvent system, which are compositionally stable, environmentally safe, can be produced efficiently in large quantity and which, because of their high conductivities .apprxeq.10.sup.-3 .OMEGA..sup.-1 cm.sup.-1 are useful as electrolytes for rechargeable lithium batteries.

Allele-Specific Transcription Factor Binding in Pig Calpastatin Promoter Regions

USDA-ARS?s Scientific Manuscript database

The identification of predictive DNA markers for pork quality would allow U.S. pork producers and breeders to more quickly and efficiently select genetically superior animals for production of consistent, high quality meat. Genome scans have identified QTL for tenderness on pig chromosome 2 which ha...

Predictive markers in calpastatin for tenderness in commercial pig populations

USDA-ARS?s Scientific Manuscript database

The identification of predictive DNA markers for pork quality would allow U.S. pork producers and breeders to more quickly and efficiently select genetically superior animals for production of consistent, high quality meat. Genome scans have identified QTL for tenderness on pig chromosome 2 which ha...

Association of Functional SNPs in Pig Calpastatin Regulatory Regions with Tenderness

USDA-ARS?s Scientific Manuscript database

The identification of predictive DNA markers for pork quality would allow U.S. pork producers and breeders to more quickly and efficiently select genetically superior animals for production of consistent, high quality meat. Genome scans have identified QTL for tenderness on pig chromosome 2 which ha...

Tunable, rare earth-doped solid state lasers

DOEpatents

Emmett, John L.; Jacobs, Ralph R.; Krupke, William F.; Weber, Marvin J.

1980-01-01

Laser apparatus comprising combinations of an excimer pump laser and a rare earth-doped solid matrix, utilizing the 5d-4f radiative transition in a rare earth ion to produce visible and ultra-violet laser radiation with high overall efficiency in selected cases and relatively long radiative lifetimes.

Seizing Workplace Learning Affordances in High-Pressure Work Environments

ERIC Educational Resources Information Center

Gnaur, Dorina

2010-01-01

Work in call centres is often presented as a form of unskilled labour characterized by routinization, technological surveillance and tight management control aimed at reaching intensive performance targets. Beyond delivering business objectives, this control and efficiency strategy is often held to produce counterproductive effects with regard to…

Genetically modified yeast of the species Issatchenkia orientalis and closely relates species, and fermentation processes using same

DOEpatents

Suominen, Pirkko [Maple Grove, MN; Aristidou, Aristos [Highland Ranch, CO; Pentilla, Merja [Helsinki, FI; Ilmen, Marja [Helsinki, FI; Ruohonen, Laura [Helsinki, FI; Koivuranta, Kari [Vantaa, FI; Roberg-Perez, Kevin [Minneapolis, MN

2012-01-17

Cells of the species Issatchenkia orientalis and closely related yeast species are transformed with a vector to introduce an exogenous lactate dehydrogenase gene. The cells produce lactic acid efficiently and are resistant at low pH, high lactate titer conditions.

Temperature-sensitive PSII: a novel approach for sustained photosynthetic hydrogen production.

PubMed

Bayro-Kaiser, Vinzenz; Nelson, Nathan

2016-12-01

The need for energy and the associated burden are ever growing. It is crucial to develop new technologies for generating clean and efficient energy for society to avoid upcoming energetic and environmental crises. Sunlight is the most abundant source of energy on the planet. Consequently, it has captured our interest. Certain microalgae possess the ability to capture solar energy and transfer it to the energy carrier, H 2 . H 2 is a valuable fuel, because its combustion produces only one by-product: water. However, the establishment of an efficient biophotolytic H 2 production system is hindered by three main obstacles: (1) the hydrogen-evolving enzyme, [FeFe]-hydrogenase, is highly sensitive to oxygen; (2) energy conversion efficiencies are not economically viable; and (3) hydrogen-producing organisms are sensitive to stressful conditions in large-scale production systems. This study aimed to circumvent the oxygen sensitivity of this process with a cyclic hydrogen production system. This approach required a mutant that responded to high temperatures by reducing oxygen evolution. To that end, we randomly mutagenized the green microalgae, Chlamydomonas reinhardtii, to generate mutants that exhibited temperature-sensitive photoautotrophic growth. The selected mutants were further characterized by their ability to evolve oxygen and hydrogen at 25 and 37 °C. We identified four candidate mutants for this project. We characterized these mutants with PSII fluorescence, P700 absorbance, and immunoblotting analyses. Finally, we demonstrated that these mutants could function in a prototype hydrogen-producing bioreactor. These mutant microalgae represent a novel approach for sustained hydrogen production.

Factors that influence the efficiency of beef and dairy cattle recording system in Kenya: A SWOT-AHP analysis.

PubMed

Wasike, Chrilukovian B; Magothe, Thomas M; Kahi, Alexander K; Peters, Kurt J

2011-01-01

Animal recording in Kenya is characterised by erratic producer participation and high drop-out rates from the national recording scheme. This study evaluates factors influencing efficiency of beef and dairy cattle recording system. Factors influencing efficiency of animal identification and registration, pedigree and performance recording, and genetic evaluation and information utilisation were generated using qualitative and participatory methods. Pairwise comparison of factors was done by strengths, weaknesses, opportunities and threats-analytical hierarchical process analysis and priority scores to determine their relative importance to the system calculated using Eigenvalue method. For identification and registration, and evaluation and information utilisation, external factors had high priority scores. For pedigree and performance recording, threats and weaknesses had the highest priority scores. Strengths factors could not sustain the required efficiency of the system. Weaknesses of the system predisposed it to threats. Available opportunities could be explored as interventions to restore efficiency in the system. Defensive strategies such as reorienting the system to offer utility benefits to recording, forming symbiotic and binding collaboration between recording organisations and NARS, and development of institutions to support recording were feasible.

Bifacial Si heterojunction-perovskite organic-inorganic tandem to produce highly efficient ( ηT * ˜ 33%) solar cell

NASA Astrophysics Data System (ADS)

Asadpour, Reza; Chavali, Raghu V. K.; Ryyan Khan, M.; Alam, Muhammad A.

2015-06-01

As single junction photovoltaic (PV) technologies, both Si heterojunction (HIT) and perovskite based solar cells promise high efficiencies at low cost. Intuitively, a traditional tandem cell design with these cells connected in series is expected to improve the efficiency further. Using a self-consistent numerical modeling of optical and transport characteristics, however, we find that a traditional series connected tandem design suffers from low J S C due to band-gap mismatch and current matching constraints. Specifically, a traditional tandem cell with state-of-the-art HIT ( η = 24 % ) and perovskite ( η = 20 % ) sub-cells provides only a modest tandem efficiency of η T ˜ 25%. Instead, we demonstrate that a bifacial HIT/perovskite tandem design decouples the optoelectronic constraints and provides an innovative path for extraordinary efficiencies. In the bifacial configuration, the same state-of-the-art sub-cells achieve a normalized output of ηT * = 33%, exceeding the bifacial HIT performance at practical albedo reflections. Unlike the traditional design, this bifacial design is relatively insensitive to perovskite thickness variations, which may translate to simpler manufacture and higher yield.

High efficiency 4H-SiC betavoltaic power sources using tritium radioisotopes

NASA Astrophysics Data System (ADS)

Thomas, Christopher; Portnoff, Samuel; Spencer, M. G.

2016-01-01

Realization of an 18.6% efficient 4H-silicon carbide (4H-SiC) large area betavoltaic power source using the radioisotope tritium is reported. A 200 nm 4H-SiC P+N junction is used to collect high-energy electrons. The electron source is a titanium tritide (TiH3x) foil, or an integrated titanium tritide region formed by the diffusion of tritium into titanium. The specific activity of the source is directly measured. Dark current measured under short circuit conditions was less than 6.1 pA/cm2. Samples measured with an external tritium foil produced an open circuit voltage of 2.09 V, short circuit current of 75.47 nA/cm2, fill factor of 0.86, and power efficiency of 18.6%. Samples measured with an integrated source produced power efficiencies of 12%. Simulations were done to determine the beta spectrum (modified by self absorption) exiting the source and the electron hole pair generation function in the 4H-SiC. The electron-hole pair generation function in 4H-SiC was modeled as a Gaussian distribution, and a closed form solution of the continuity equation was used to analyze the cell performance. The effective surface recombination velocity in our samples was found to be 105-106 cm/s. Our analysis demonstrated that the surface recombination dominates the performance of a tritium betavoltaic device but that using a thin P+N junction structure can mitigate some of the negative effects.

An efficient strategy for producing a stable, replaceable, highly efficient transgene expression system in silkworm, Bombyx mori

PubMed Central

Long, Dingpei; Lu, Weijian; Zhang, Yuli; Bi, Lihui; Xiang, Zhonghuai; Zhao, Aichun

2015-01-01

We developed an efficient strategy that combines a method for the post-integration elimination of all transposon sequences, a site-specific recombination system, and an optimized fibroin H-chain expression system to produce a stable, replaceable, highly efficient transgene expression system in the silkworm (Bombyx mori) that overcomes the disadvantages of random insertion and post-integration instability of transposons. Here, we generated four different transgenic silkworm strains, and of one the transgenic strains, designated TS1-RgG2, with up to 16% (w/w) of the target protein in the cocoons, was selected. The subsequent elimination of all the transposon sequences from TS1-RgG2 was completed by the heat-shock-induced expression of the transposase in vivo. The resulting transgenic silkworm strain was designated TS3-g2 and contained only the attP-flanked optimized fibroin H-chain expression cassette in its genome. A phiC31/att-system-based recombinase-mediated cassette exchange (RMCE) method could be used to integrate other genes of interest into the same genome locus between the attP sites in TS3-g2. Controlling for position effects with phiC31-mediated RMCE will also allow the optimization of exogenous protein expression and fine gene function analyses in the silkworm. The strategy developed here is also applicable to other lepidopteran insects, to improve the ecological safety of transgenic strains in biocontrol programs. PMID:25739894

THE IMPACT OF STELLAR FEEDBACK ON THE STRUCTURE, SIZE, AND MORPHOLOGY OF GALAXIES IN MILKY-WAY-SIZED DARK MATTER HALOS

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

Agertz, Oscar; Kravtsov, Andrey V., E-mail: o.agertz@surrey.ac.uk

We use cosmological zoom-in simulations of galaxy formation in a Milky-Way-sized halo started from identical initial conditions to investigate the evolution of galaxy sizes, baryon fractions, morphologies, and angular momenta in runs with different parameters of the star formation–feedback cycle. Our fiducial model with a high local star formation efficiency, which results in efficient feedback, produces a realistic late-type galaxy that matches the evolution of basic properties of late-type galaxies: stellar mass, disk size, morphology dominated by a kinematically cold disk, stellar and gas surface density profiles, and specific angular momentum. We argue that feedback’s role in this success ismore » twofold: (1) removal of low angular momentum gas, and (2) maintaining a low disk-to-halo mass fraction, which suppresses disk instabilities that lead to angular momentum redistribution and a central concentration of baryons. However, our model with a low local star formation efficiency, but large energy input per supernova, chosen to produce a galaxy with a similar star formation history as our fiducial model, leads to a highly irregular galaxy with no kinematically cold component, overly extended stellar distribution, and low angular momentum. This indicates that only when feedback is allowed to become vigorous via locally efficient star formation in dense cold gas do resulting galaxy sizes, gas/stellar surface density profiles, and stellar disk angular momenta agree with observed z = 0 galaxies.« less

Growth of Nanosized Single Crystals for Efficient Perovskite Light-Emitting Diodes.

PubMed

Lee, Seungjin; Park, Jong Hyun; Nam, Yun Seok; Lee, Bo Ram; Zhao, Baodan; Di Nuzzo, Daniele; Jung, Eui Dae; Jeon, Hansol; Kim, Ju-Young; Jeong, Hu Young; Friend, Richard H; Song, Myoung Hoon

2018-04-24

Organic-inorganic hybrid perovskites are emerging as promising emitting materials due to their narrow full-width at half-maximum emissions, color tunability, and high photoluminescence quantum yields (PLQYs). However, the thermal generation of free charges at room temperature results in a low radiative recombination rate and an excitation-intensity-dependent PLQY, which is associated with the trap density. Here, we report perovskite films composed of uniform nanosized single crystals (average diameter = 31.7 nm) produced by introducing bulky amine ligands and performing the growth at a lower temperature. By effectively controlling the crystal growth, we maximized the radiative bimolecular recombination yield by reducing the trap density and spatially confining the charges. Finally, highly bright and efficient green emissive perovskite light-emitting diodes that do not suffer from electroluminescence blinking were achieved with a luminance of up to 55 400 cd m -2 , current efficiency of 55.2 cd A -1 , and external quantum efficiency of 12.1%.

Stirling Air Conditioner for Compact Cooling

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

None

2010-09-01

BEETIT Project: Infinia is developing a compact air conditioner that uses an unconventional high efficient Stirling cycle system (vs. conventional vapor compression systems) to produce cool air that is energy efficient and does not rely on polluting refrigerants. The Stirling cycle system is a type of air conditioning system that uses a motor with a piston to remove heat to the outside atmosphere using a gas refrigerant. To date, Stirling systems have been expensive and have not had the right kind of heat exchanger to help cool air efficiently. Infinia is using chip cooling technology from the computer industry tomore » make improvements to the heat exchanger and improve system performance. Infinia’s air conditioner uses helium gas as refrigerant, an environmentally benign gas that does not react with other chemicals and does not burn. Infinia’s improvements to the Stirling cycle system will enable the cost-effective mass production of high-efficiency air conditioners that use no polluting refrigerants.« less

Highly efficient solar-pumped Nd:YAG laser.

PubMed

Liang, Dawei; Almeida, Joana

2011-12-19

The recent progress in solar-pumped laser with Fresnel lens and Cr:Nd:YAG ceramic medium has revitalized solar laser researches, revealing a promising future for renewable reduction of magnesium from magnesium oxide. Here we show a big advance in solar laser collection efficiency by utilizing an economical Fresnel lens and a most widely used Nd:YAG single-crystal rod. The incoming solar radiation from the sun is focused by a 0.9 m diameter Fresnel lens. A dielectric totally internally reflecting secondary concentrator is employed to couple the concentrated solar radiation from the focal zone to a 4 mm diameter Nd:YAG rod within a conical pumping cavity. 12.3 W cw laser power is produced, corresponding to 19.3 W/m(2) collection efficiency, which is 2.9 times larger than the previous results with Nd:YAG single-crystal medium. Record-high slope efficiency of 3.9% is also registered. Laser beam quality is considerably improved by pumping a 3 mm diameter Nd:YAG rod.

Synthesis of Silane and Silicon in a Non-equilibrium Plasma Jet

NASA Technical Reports Server (NTRS)

Calcote, H. F.

1978-01-01

The original objective of this program was to determine the feasibility of high volume, low-cost production of high purity silane or solar cell grade silicon using a non equilibrium plasma jet. The emphasis was changed near the end of the program to determine the feasibility of preparing photovoltaic amorphous silicon films directly using this method. The non equilibrium plasma jet should be further evaluated as a technique for producing high efficiency photovoltaic amorphous silicon films.

Development of carbon plasma-coated multiwell plates for high-throughput mass spectrometric analysis of highly lipophilic fermentation products.

PubMed

Heinig, Uwe; Scholz, Susanne; Dahm, Pia; Grabowy, Udo; Jennewein, Stefan

2010-08-01

Classical approaches to strain improvement and metabolic engineering rely on rapid qualitative and quantitative analyses of the metabolites of interest. As an analytical tool, mass spectrometry (MS) has proven to be efficient and nearly universally applicable for timely screening of metabolites. Furthermore, gas chromatography (GC)/MS- and liquid chromatography (LC)/MS-based metabolite screens can often be adapted to high-throughput formats. We recently engineered a Saccharomyces cerevisiae strain to produce taxa-4(5),11(12)-diene, the first pathway-committing biosynthetic intermediate for the anticancer drug Taxol, through the heterologous and homologous expression of several genes related to isoprenoid biosynthesis. To date, GC/MS- and LC/MS-based high-throughput methods have been inherently difficult to adapt to the screening of isoprenoid-producing microbial strains due to the need for extensive sample preparation of these often highly lipophilic compounds. In the current work, we examined different approaches to the high-throughput analysis of taxa-4(5),11(12)-diene biosynthesizing yeast strains in a 96-deep-well format. Carbon plasma coating of standard 96-deep-well polypropylene plates allowed us to circumvent the inherent solvent instability of commonly used deep-well plates. In addition, efficient adsorption of the target isoprenoid product by the coated plates allowed rapid and simple qualitative and quantitative analyses of the individual cultures. Copyright 2010 Elsevier Inc. All rights reserved.

Improving the efficiency of CHO cell line generation using glutamine synthetase gene knockout cells.

PubMed

Fan, Lianchun; Kadura, Ibrahim; Krebs, Lara E; Hatfield, Christopher C; Shaw, Margaret M; Frye, Christopher C

2012-04-01

Although Chinese hamster ovary (CHO) cells, with their unique characteristics, have become a major workhorse for the manufacture of therapeutic recombinant proteins, one of the major challenges in CHO cell line generation (CLG) is how to efficiently identify those rare, high-producing clones among a large population of low- and non-productive clones. It is not unusual that several hundred individual clones need to be screened for the identification of a commercial clonal cell line with acceptable productivity and growth profile making the cell line appropriate for commercial application. This inefficiency makes the process of CLG both time consuming and laborious. Currently, there are two main CHO expression systems, dihydrofolate reductase (DHFR)-based methotrexate (MTX) selection and glutamine synthetase (GS)-based methionine sulfoximine (MSX) selection, that have been in wide industrial use. Since selection of recombinant cell lines in the GS-CHO system is based on the balance between the expression of the GS gene introduced by the expression plasmid and the addition of the GS inhibitor, L-MSX, the expression of GS from the endogenous GS gene in parental CHOK1SV cells will likely interfere with the selection process. To study endogenous GS expression's potential impact on selection efficiency, GS-knockout CHOK1SV cell lines were generated using the zinc finger nuclease (ZFN) technology designed to specifically target the endogenous CHO GS gene. The high efficiency (∼2%) of bi-allelic modification on the CHO GS gene supports the unique advantages of the ZFN technology, especially in CHO cells. GS enzyme function disruption was confirmed by the observation of glutamine-dependent growth of all GS-knockout cell lines. Full evaluation of the GS-knockout cell lines in a standard industrial cell culture process was performed. Bulk culture productivity improved two- to three-fold through the use of GS-knockout cells as parent cells. The selection stringency was significantly increased, as indicated by the large reduction of non-producing and low-producing cells after 25 µM L-MSX selection, and resulted in a six-fold efficiency improvement in identifying similar numbers of high-productive cell lines for a given recombinant monoclonal antibody. The potential impact of GS-knockout cells on recombinant protein quality is also discussed. Copyright © 2011 Wiley Periodicals, Inc.

Logic circuits composed of flexible carbon nanotube thin-film transistor and ultra-thin polymer gate dielectric

PubMed Central

Lee, Dongil; Yoon, Jinsu; Lee, Juhee; Lee, Byung-Hyun; Seol, Myeong-Lok; Bae, Hagyoul; Jeon, Seung-Bae; Seong, Hyejeong; Im, Sung Gap; Choi, Sung-Jin; Choi, Yang-Kyu

2016-01-01

Printing electronics has become increasingly prominent in the field of electronic engineering because this method is highly efficient at producing flexible, low-cost and large-scale thin-film transistors. However, TFTs are typically constructed with rigid insulating layers consisting of oxides and nitrides that are brittle and require high processing temperatures, which can cause a number of problems when used in printed flexible TFTs. In this study, we address these issues and demonstrate a method of producing inkjet-printed TFTs that include an ultra-thin polymeric dielectric layer produced by initiated chemical vapor deposition (iCVD) at room temperature and highly purified 99.9% semiconducting carbon nanotubes. Our integrated approach enables the production of flexible logic circuits consisting of CNT-TFTs on a polyethersulfone (PES) substrate that have a high mobility (up to 9.76 cm2 V−1 sec−1), a low operating voltage (less than 4 V), a high current on/off ratio (3 × 104), and a total device yield of 90%. Thus, it should be emphasized that this study delineates a guideline for the feasibility of producing flexible CNT-TFT logic circuits with high performance based on a low-cost and simple fabrication process. PMID:27184121

Logic circuits composed of flexible carbon nanotube thin-film transistor and ultra-thin polymer gate dielectric

NASA Astrophysics Data System (ADS)

Lee, Dongil; Yoon, Jinsu; Lee, Juhee; Lee, Byung-Hyun; Seol, Myeong-Lok; Bae, Hagyoul; Jeon, Seung-Bae; Seong, Hyejeong; Im, Sung Gap; Choi, Sung-Jin; Choi, Yang-Kyu

2016-05-01

Printing electronics has become increasingly prominent in the field of electronic engineering because this method is highly efficient at producing flexible, low-cost and large-scale thin-film transistors. However, TFTs are typically constructed with rigid insulating layers consisting of oxides and nitrides that are brittle and require high processing temperatures, which can cause a number of problems when used in printed flexible TFTs. In this study, we address these issues and demonstrate a method of producing inkjet-printed TFTs that include an ultra-thin polymeric dielectric layer produced by initiated chemical vapor deposition (iCVD) at room temperature and highly purified 99.9% semiconducting carbon nanotubes. Our integrated approach enables the production of flexible logic circuits consisting of CNT-TFTs on a polyethersulfone (PES) substrate that have a high mobility (up to 9.76 cm2 V-1 sec-1), a low operating voltage (less than 4 V), a high current on/off ratio (3 × 104), and a total device yield of 90%. Thus, it should be emphasized that this study delineates a guideline for the feasibility of producing flexible CNT-TFT logic circuits with high performance based on a low-cost and simple fabrication process.

a High-Density Electron Beam and Quad-Scan Measurements at Pleiades Thomson X-Ray Source

NASA Astrophysics Data System (ADS)

Lim, J. K.; Rosenzweig, J. B.; Anderson, S. G.; Tremaine, A. M.

2007-09-01

A recent development of the photo-cathode injector technology has greatly enhanced the beam quality necessary for the creation of high density/high brightness electron beam sources. In the Thomson backscattering x-ray experiment, there is an immense need for under 20 micron electron beam spot at the interaction point with a high-intensity laser in order to produce a large x-ray flux. This has been demonstrated successfully at PLEIADES in Lawrence Livermore National Laboratory. For this Thomson backscattering experiment, we employed an asymmetric triplet, high remanence permanent-magnet quads to produce smaller electron beams. Utilizing highly efficient optical transition radiation (OTR) beam spot imaging technique and varying electron focal spot sizes enabled a quadrupole scan at the interaction zone. Comparisons between Twiss parameters obtained upstream to those parameter values deduced from PMQ scan will be presented in this report.

a High-Density Electron Beam and Quad-Scan Measurements at Pleiades Thomson X-Ray Source

NASA Astrophysics Data System (ADS)

Lim, J. K.; Rosenzweig, J. B.; Anderson, S. G.; Tremaine, A. M.

A recent development of the photo-cathode injector technology has greatly enhanced the beam quality necessary for the creation of high density/high brightness electron beam sources. In the Thomson backscattering x-ray experiment, there is an immense need for under 20 micron electron beam spot at the interaction point with a high-intensity laser in order to produce a large x-ray flux. This has been demonstrated successfully at PLEIADES in Lawrence Livermore National Laboratory. For this Thomson backscattering experiment, we employed an asymmetric triplet, high remanence permanent-magnet quads to produce smaller electron beams. Utilizing highly efficient optical transition radiation (OTR) beam spot imaging technique and varying electron focal spot sizes enabled a quadrupole scan at the interaction zone. Comparisons between Twiss parameters obtained upstream to those parameter values deduced from PMQ scan will be presented in this report.

Integrating Cellular and Bioprocess Engineering in the Non-Conventional Yeast Yarrowia lipolytica for Biodiesel Production: A Review

PubMed Central

Xie, Dongming

2017-01-01

As one of the major biofuels to replace fossil fuel, biodiesel has now attracted more and more attention due to its advantages in higher energy density and overall less greenhouse gas generation. Biodiesel (fatty acid alkyl esters) is produced by chemically or enzymatically catalyzed transesterification of lipids from microbial cells, microalgae, oil crops, or animal fats. Currently, plant oils or waste cooking oils/fats remain the major source for biodiesel production via enzymatic route, but the production capacity is limited either by the uncertain supplement of plant oils or by the low or inconsistent quality of waste oils/fats. In the past decades, significant progresses have been made on synthesis of microalgae oils directly from CO2 via a photosynthesis process, but the production cost from any current technologies is still too high to be commercialized due to microalgae’s slow growth rate on CO2, inefficiency in photo-bioreactors, lack of efficient contamination control methods, and high cost in downstream recovery. At the same time, many oleaginous microorganisms have been studied to produce lipids via the fatty acid synthesis pathway under aerobic fermentation conditions, among them one of the most studied is the non-conventional yeast, Yarrowia lipolytica, which is able to produce fatty acids at very high titer, rate, and yield from various economical substrates. This review summarizes the recent research progresses in both cellular and bioprocess engineering in Y. lipolytica to produce lipids at a low cost that may lead to commercial-scale biodiesel production. Specific technologies include the strain engineering for using various substrates, metabolic engineering in high-yield lipid synthesis, cell morphology study for efficient substrate uptake and product formation, free fatty acid formation and secretion for improved downstream recovery, and fermentation engineering for higher productivities and less operating cost. To further improve the economics of the microbial oil-based biodiesel, production of lipid-related or -derived high-value products are also discussed. PMID:29090211

[Tobacco--a highly efficient producer of vaccines].

PubMed

Budzianowski, Jaromir

2010-01-01

Along with the depreciation of tobacco as a source of nicotine-containing commercial products, the increase of its appreciation as a potential producer of recombinant therapeutical proteins can be observed. Two species of tobacco--Nicotiana tabacum L. and N. benthamiana are easily grown by well established methods of field or green-house cultivation or cell culture, yield high biomass and soluble protein content, can be easily transformed by several methods and are not food for humans or feed for animals. Expression of foreign proteins, including vaccines, can be achieved in those plants either through stable transformation of nuclear or plastid (chloroplast) genomes or by transient transformation using infection with plant virus or bacteria--Agrobacterium tumefaciens (agroinfiltration). The most advanced mode of agrofiltration termed magnifection, which combines benefits of virus and Agrobacterium and depends on using Agrobacterium with viral pro-vectors, enables high-yield and rapid expression of therapeutical proteins, even in a few days, and can be employed on an industrial scale. Expression of many antigenic proteins, which may serve as antiviral, antibacterial, antiprotozoan and anticancer vaccines, and additionally a few autoantigens designed for the treatment of autoimunogenic diseases, like diabetes, have been achieved in tobacco. To date, a vaccine against Newcastle virus disease in poultry produced by tobacco cell culture has been approved for commercial application and several other vaccines are in advanced stage of development. The possibility of a high-level production of vaccines in tobacco against pandemic influenza or anthrax and plague due to a bioterroristic attack, as well as of individualised anticancer vaccines against non-Hodgkin's lymphoma (NHL) in a much shorter period of time than by traditional methods became realistic and hence caused increased interest in tobacco as a high-efficient producer of vaccines not only of specialistic biotechnology firms but also a big pharmaceutical corporation and a department of defence.

Tree branch-shaped cupric oxide for highly effective photoelectrochemical water reduction

NASA Astrophysics Data System (ADS)

Jang, Youn Jeong; Jang, Ji-Wook; Choi, Sun Hee; Kim, Jae Young; Kim, Ju Hun; Youn, Duck Hyun; Kim, Won Yong; Han, Suenghoon; Sung Lee, Jae

2015-04-01

Highly efficient tree branch-shaped CuO photocathodes are fabricated using the hybrid microwave annealing process with a silicon susceptor within 10 minutes. The unique hierarchical, one-dimensional structure provides more facile charge transport, larger surface areas, and increased crystallinity and crystal ordering with less defects compared to irregular-shaped CuO prepared by conventional thermal annealing. As a result, the photocathode fabricated with the tree branch-shaped CuO produces an unprecedently high photocurrent density of -4.4 mA cm-2 at 0 VRHE under AM 1.5 G simulated sunlight compared to -1.44 mA cm-2 observed for a photocathode fabricated by thermal annealing. It is also confirmed that stoichiometric hydrogen and oxygen are produced from photoelectrochemical water splitting on the tree branch-shaped CuO photocathode and a platinum anode.Highly efficient tree branch-shaped CuO photocathodes are fabricated using the hybrid microwave annealing process with a silicon susceptor within 10 minutes. The unique hierarchical, one-dimensional structure provides more facile charge transport, larger surface areas, and increased crystallinity and crystal ordering with less defects compared to irregular-shaped CuO prepared by conventional thermal annealing. As a result, the photocathode fabricated with the tree branch-shaped CuO produces an unprecedently high photocurrent density of -4.4 mA cm-2 at 0 VRHE under AM 1.5 G simulated sunlight compared to -1.44 mA cm-2 observed for a photocathode fabricated by thermal annealing. It is also confirmed that stoichiometric hydrogen and oxygen are produced from photoelectrochemical water splitting on the tree branch-shaped CuO photocathode and a platinum anode. Electronic supplementary information (ESI) available: The detailed schematic diagram for the HMA process, XRD results, the temperature profile during HMA, derivative XANES results, TEM images, J-V curves, lists of previously reported copper oxide photocathode, and parameters extracted from EIS. See DOI: 10.1039/c5nr00208g

CO2 Fixation, Lipid Production, and Power Generation by a Novel Air-Lift-Type Microbial Carbon Capture Cell System.

PubMed

Hu, Xia; Liu, Baojun; Zhou, Jiti; Jin, Ruofei; Qiao, Sen; Liu, Guangfei

2015-09-01

An air-lift-type microbial carbon capture cell (ALMCC) was constructed for the first time by using an air-lift-type photobioreactor as the cathode chamber. The performance of ALMCC in fixing high concentration of CO2, producing energy (power and biodiesel), and removing COD together with nutrients was investigated and compared with the traditional microbial carbon capture cell (MCC) and air-lift-type photobioreactor (ALP). The ALMCC system produced a maximum power density of 972.5 mW·m(-3) and removed 86.69% of COD, 70.52% of ammonium nitrogen, and 69.24% of phosphorus, which indicate that ALMCC performed better than MCC in terms of power generation and wastewater treatment efficiency. Besides, ALMCC demonstrated 9.98- and 1.88-fold increases over ALP and MCC in the CO2 fixation rate, respectively. Similarly, the ALMCC significantly presented a higher lipid productivity compared to those control reactors. More importantly, the preliminary analysis of energy balance suggested that the net energy of the ALMCC system was significantly superior to other systems and could theoretically produce enough energy to cover its consumption. In this work, the established ALMCC system simultaneously achieved the high level of CO2 fixation, energy recycle, and municipal wastewater treatment effectively and efficiently.

High-efficiency scintillation detector for combined detection of thermal and fast neutrons and gamma radiation

DOEpatents

Chiles, M.M.; Mihalczo, J.T.; Blakeman, E.D.

1987-02-27

A scintillation based radiation detector for the combined detection of thermal neutrons, high-energy neutrons and gamma rays in a single detecting unit. The detector consists of a pair of scintillators sandwiched together and optically coupled to the light sensitive face of a photomultiplier tube. A light tight radiation pervious housing is disposed about the scintillators and a portion of the photomultiplier tube to hold the arrangement in assembly and provides a radiation window adjacent the outer scintillator through which the radiation to be detected enters the detector. The outer scintillator is formed of a material in which scintillations are produced by thermal-neutrons and the inner scintillator is formed of a material in which scintillations are produced by high-energy neutrons and gamma rays. The light pulses produced by events detected in both scintillators are coupled to the photomultiplier tube which produces a current pulse in response to each detected event. These current pulses may be processed in a conventional manner to produce a count rate output indicative of the total detected radiation event count rate. Pulse discrimination techniques may be used to distinguish the different radiations and their energy distribution.

High-efficiency scintillation detector for combined of thermal and fast neutrons and gamma radiation

DOEpatents

Chiles, Marion M.; Mihalczo, John T.; Blakeman, Edward D.

1989-02-07

A scintillation based radiation detector for the combined detection of thermal neutrons, high-energy neutrons and gamma rays in a single detecting unit. The detector consists of a pair of scintillators sandwiched together and optically coupled to the light sensitive face of a photomultiplier tube. A light tight radiation pervious housing is disposed about the scintillators and a portion of the photomultiplier tube to hold the arrangement in assembly and provides a radiation window adjacent the outer scintillator through which the radiation to be detected enters the detector. The outer scintillator is formed of a material in which scintillations are produced by thermal-neutrons and the inner scintillator is formed of a material in which scintillations are produced by high-energy neutrons and gamma rays. The light pulses produced by events detected in both scintillators are coupled to the photomultiplier tube which produces a current pulse in response to each detected event. These current pulses may be processed in a conventional manner to produce a count rate output indicative of the total detected radiation even count rate. Pulse discrimination techniques may be used to distinguish the different radiations and their energy distribution.

High-efficiency scintillation detector for combined of thermal and fast neutrons and gamma radiation

DOEpatents

Chiles, Marion M.; Mihalczo, John T.; Blakeman, Edward D.

1989-01-01

A scintillation based radiation detector for the combined detection of thermal neutrons, high-energy neutrons and gamma rays in a single detecting unit. The detector consists of a pair of scintillators sandwiched together and optically coupled to the light sensitive face of a photomultiplier tube. A light tight radiation pervious housing is disposed about the scintillators and a portion of the photomultiplier tube to hold the arrangement in assembly and provides a radiation window adjacent the outer scintillator through which the radiation to be detected enters the detector. The outer scintillator is formed of a material in which scintillations are produced by thermal-neutrons and the inner scintillator is formed of a material in which scintillations are produced by high-energy neutrons and gamma rays. The light pulses produced by events detected in both scintillators are coupled to the photomultiplier tube which produces a current pulse in response to each detected event. These current pulses may be processed in a conventional manner to produce a count rate output indicative of the total detected radiation even count rate. Pulse discrimination techniques may be used to distinguish the different radiations and their energy distribution.

High-efficiency photorealistic computer-generated holograms based on the backward ray-tracing technique

NASA Astrophysics Data System (ADS)

Wang, Yuan; Chen, Zhidong; Sang, Xinzhu; Li, Hui; Zhao, Linmin

2018-03-01

Holographic displays can provide the complete optical wave field of a three-dimensional (3D) scene, including the depth perception. However, it often takes a long computation time to produce traditional computer-generated holograms (CGHs) without more complex and photorealistic rendering. The backward ray-tracing technique is able to render photorealistic high-quality images, which noticeably reduce the computation time achieved from the high-degree parallelism. Here, a high-efficiency photorealistic computer-generated hologram method is presented based on the ray-tracing technique. Rays are parallelly launched and traced under different illuminations and circumstances. Experimental results demonstrate the effectiveness of the proposed method. Compared with the traditional point cloud CGH, the computation time is decreased to 24 s to reconstruct a 3D object of 100 ×100 rays with continuous depth change.

Towards high-resolution laser ionization spectroscopy of the heaviest elements in supersonic gas jet expansion

PubMed Central

Ferrer, R.; Barzakh, A.; Bastin, B.; Beerwerth, R.; Block, M.; Creemers, P.; Grawe, H.; de Groote, R.; Delahaye, P.; Fléchard, X.; Franchoo, S.; Fritzsche, S.; Gaffney, L. P.; Ghys, L.; Gins, W.; Granados, C.; Heinke, R.; Hijazi, L.; Huyse, M.; Kron, T.; Kudryavtsev, Yu.; Laatiaoui, M.; Lecesne, N.; Loiselet, M.; Lutton, F.; Moore, I. D.; Martínez, Y.; Mogilevskiy, E.; Naubereit, P.; Piot, J.; Raeder, S.; Rothe, S.; Savajols, H.; Sels, S.; Sonnenschein, V.; Thomas, J-C; Traykov, E.; Van Beveren, C.; Van den Bergh, P.; Van Duppen, P.; Wendt, K.; Zadvornaya, A.

2017-01-01

Resonant laser ionization and spectroscopy are widely used techniques at radioactive ion beam facilities to produce pure beams of exotic nuclei and measure the shape, size, spin and electromagnetic multipole moments of these nuclei. However, in such measurements it is difficult to combine a high efficiency with a high spectral resolution. Here we demonstrate the on-line application of atomic laser ionization spectroscopy in a supersonic gas jet, a technique suited for high-precision studies of the ground- and isomeric-state properties of nuclei located at the extremes of stability. The technique is characterized in a measurement on actinium isotopes around the N=126 neutron shell closure. A significant improvement in the spectral resolution by more than one order of magnitude is achieved in these experiments without loss in efficiency. PMID:28224987

Melt-cast organic glasses as high-efficiency fast neutron scintillators

DOE PAGES

Carlson, Joseph S.; Feng, Patrick L.

2016-06-24

In this work we report a new class of organic-based scintillators that combines several of the desirable attributes of existing crystalline, liquid, and plastic organic scintillators. The prepared materials may be isolated in single crystalline form or melt-cast to produce highly transparent glasses that have been shown to provide high light yields of up to 16,000 photons/MeVee, as evaluated against EJ-200 plastic scintillators and solution-grown trans-stilbene crystals. The prepared organic glasses exhibit neutron/gamma pulse-shape discrimination (PSD) and are compatible with wavelength shifters to reduce optical self-absorption effects that are intrinsic to pure materials such as crystalline organics. In conclusion, themore » combination of high scintillation efficiency, PSD capabilities, and facile scale-up via melt-casting distinguishes this new class of amorphous materials from existing alternatives.« less

Recent advances in microbial production of mannitol: utilization of low-cost substrates, strain development and regulation strategies.

PubMed

Zhang, Min; Gu, Lei; Cheng, Chao; Ma, Jiangfeng; Xin, Fengxue; Liu, Junli; Wu, Hao; Jiang, Min

2018-02-26

Mannitol has been widely used in fine chemicals, pharmaceutical industries, as well as functional foods due to its excellent characteristics, such as antioxidant protecting, regulation of osmotic pressure and non-metabolizable feature. Mannitol can be naturally produced by microorganisms. Compared with chemical manufacturing, microbial production of mannitol provides high yield and convenience in products separation; however the fermentative process has not been widely adopted yet. A major obstacle to microbial production of mannitol under industrial-scale lies in the low economical efficiency, owing to the high cost of fermentation medium, leakage of fructose, low mannitol productivity. In this review, recent advances in improving the economical efficiency of microbial production of mannitol were reviewed, including utilization of low-cost substrates, strain development for high mannitol yield and process regulation strategies for high productivity.

Water-activated graphite felt as a high-performance electrode for vanadium redox flow batteries

NASA Astrophysics Data System (ADS)

Kabtamu, Daniel Manaye; Chen, Jian-Yu; Chang, Yu-Chung; Wang, Chen-Hao

2017-02-01

A simple, green, novel, time-efficient, and potentially cost-effective water activation method was employed to enhance the electrochemical activity of graphite felt (GF) electrodes for vanadium redox flow batteries (VRFBs). The GF electrode prepared with a water vapor injection time of 5 min at 700 °C exhibits the highest electrochemical activity for the VO2+/VO2+ couple among all the tested electrodes. This is attributed to the small, controlled amount of water vapor that was introduced producing high contents of oxygen-containing functional groups, such as sbnd OH groups, on the surface of the GF fibers, which are known to be electrochemically active sites for vanadium redox reactions. Charge-discharge tests further confirm that only 5 min of GF water activation is required to improve the efficiency of the VRFB cell. The average coulombic efficiency, voltage efficiency, and energy efficiency are 95.06%, 87.42%, and 83.10%, respectively, at a current density of 50 mA cm-2. These voltage and energy efficiencies are determined to be considerably higher than those of VRFB cells assembled using heat-treated GF electrodes without water activation and pristine GF electrodes.

A systematic review on the efficiency of cerium-impregnated activated carbons for the removal of gas-phase, elemental mercury from flue gas.

PubMed

Sowlat, Mohammad Hossein; Kakavandi, Babak; Lotfi, Saeedeh; Yunesian, Masud; Abdollahi, Mohammad; Rezaei Kalantary, Roshanak

2017-05-01

In the present systematic review, we aimed to collect and analyze all the relevant evidence on the efficiency of cerium-impregnated versus virgin-activated carbons (ACs) for the removal of gas-phase elemental mercury (Hg 0 ) from the flue gas of coal-fired power plants and to assess the effect of different calcination and operational parameters on their efficiency. A total of eight relevant papers (out of 1193 hits produced by the search) met the eligibility criteria and were included in the study. Results indicated that the Hg 0 adsorption capacity of cerium-impregnated ACs is significantly higher than that of virgin ACs, depending highly on the impregnation and operational parameters. It was noticed that although cerium-impregnated ACs possessed smaller surface areas and pore volumes, their Hg 0 removal efficiencies were still higher than their virgin counterparts. An increased Hg 0 removal efficiency was in general found by increasing the operational adsorption temperature as high as 150-170 °C. Studies also indicated that NO, SO 2 , and HCl have promoting impacts on the Hg 0 removal efficiency of Ce-impregnated ACs, while H 2 O has an inhibitory effect.

Analysis and Optimization of Four-Coil Planar Magnetically Coupled Printed Spiral Resonators.

PubMed

Khan, Sadeque Reza; Choi, GoangSeog

2016-08-03

High-efficiency power transfer at a long distance can be efficiently established using resonance-based wireless techniques. In contrast to the conventional two-coil-based inductive links, this paper presents a magnetically coupled fully planar four-coil printed spiral resonator-based wireless power-transfer system that compensates the adverse effect of low coupling and improves efficiency by using high quality-factor coils. A conformal architecture is adopted to reduce the transmitter and receiver sizes. Both square architecture and circular architectures are analyzed and optimized to provide maximum efficiency at a certain operating distance. Furthermore, their performance is compared on the basis of the power-transfer efficiency and power delivered to the load. Square resonators can produce higher measured power-transfer efficiency (79.8%) than circular resonators (78.43%) when the distance between the transmitter and receiver coils is 10 mm of air medium at a resonant frequency of 13.56 MHz. On the other hand, circular coils can deliver higher power (443.5 mW) to the load than the square coils (396 mW) under the same medium properties. The performance of the proposed structures is investigated by simulation using a three-layer human-tissue medium and by experimentation.

Effects of sodium salicylate on the determination of Lead-210/Bismuth-210 by Cerenkov counting.

PubMed

Wang, Yadong; Yang, Yonggang; Song, Lijuan; Ma, Yan; Luo, Maoyi; Dai, Xiongxin

2018-05-21

Due to the nature of Cerenkov radiation and instrumental limitations, detection efficiencies of 210 Bi by Cerenkov counting are generally quite low (~15%). Sodium salicylate, acting as a wavelength shifter, has been used to improve the detection efficiency of Cerenkov photons. In this study, we found that the addition of sodium salicylate could significantly increase the counting efficiencies of 210 Pb/ 210 Bi in aqueous samples. Meanwhile, a sharp increase of the counting efficiency for the alphas from 210 Po was also observed with the addition of high concentration of sodium salicylate, implying that scintillation light rather than Cerenkov photons from the alphas has been produced. Detailed studies about the effects of sodium salicylate on the counting of 210 Pb, 210 Bi and 210 Po were conducted. At low concentration (< 0.5 mg g -1 ) of sodium salicylate, only a small increase in Cerenkov counting efficiency for 210 Bi by the wavelength-shifting effect could be observed. Meanwhile, the counting efficiency for 210 Bi at high concentration (> 1 mg g -1 ) of sodium salicylate would significantly increase due to the scintillation effect. Copyright © 2018 Elsevier Ltd. All rights reserved.

Effects of electrode settings on chlorine generation efficiency of electrolyzing seawater.

PubMed

Hsu, Guoo-Shyng Wang; Hsia, Chih-Wei; Hsu, Shun-Yao

2015-12-01

Electrolyzed water has significant disinfection effects, can comply with food safety regulations, and is environmental friendly. We investigated the effects of immersion depth of electrodes, stirring, electrode size, and electrode gap on the properties and chlorine generation efficiency of electrolyzing seawater and its storage stability. Results indicated that temperature and oxidation-reduction potential (ORP) of the seawater increased gradually, whereas electrical conductivity decreased steadily in electrolysis. During the electrolysis process, pH values and electric currents also decreased slightly within small ranges. Additional stirring or immersing the electrodes deep under the seawater significantly increased current density without affecting its electric efficiency and current efficiency. Decreasing electrode size or increasing electrode gap decreased chlorine production and electric current of the process without affecting its electric efficiency and current efficiency. Less than 35% of chlorine in the electrolyzed seawater was lost in a 3-week storage period. The decrement trend leveled off after the 1 st week of storage. The electrolyzing system is a convenient and economical method for producing high-chlorine seawater, which will have high potential applications in agriculture, aquaculture, or food processing. Copyright © 2015. Published by Elsevier B.V.

High efficiency solar cells for concentrator systems: silicon or multi-junction?

NASA Astrophysics Data System (ADS)

Slade, Alexander; Stone, Kenneth W.; Gordon, Robert; Garboushian, Vahan

2005-08-01

Amonix has become the first company to begin production of high concentration silicon solar cells where volumes are over 10 MW/year. Higher volumes are available due to the method of manufacture; Amonix solely uses semiconductor foundries for solar cell production. In the previous years of system and cell field testing, this method of manufacturing enabled Amonix to maintain a very low overhead while incurring a high cost for the solar cell. However, recent simplifications to the solar cell processing sequence resulted in cost reduction and increased yield. This new process has been tested by producing small qualities in very short time periods, enabling a simulation of high volume production. Results have included over 90% wafer yield, up to 100% die yield and world record performance (η =27.3%). This reduction in silicon solar cell cost has increased the required efficiency for multi-junction concentrator solar cells to be competitive / advantageous. Concentrator systems are emerging as a low-cost, high volume option for solar-generated electricity due to the very high utilization of the solar cell, leading to a much lower $/Watt cost of a photovoltaic system. Parallel to this is the onset of alternative solar cell technologies, such as the very high efficiency multi-junction solar cells developed at NREL over the last two decades. The relatively high cost of these type of solar cells has relegated their use to non-terrestrial applications. However, recent advancements in both multi-junction concentrator cell efficiency and their stability under high flux densities has made their large-scale terrestrial deployment significantly more viable. This paper presents Amonix's experience and testing results of both high-efficiency silicon rear-junction solar cells and multi-junction solar cells made for concentrated light operation.

Conceptual design and experiments of electrochemistry-flushing technology for the remediation of historically Cr(Ⅵ)-contaminated soil.

PubMed

Li, Dong; Sun, Delin; Hu, Siyang; Hu, Jing; Yuan, Xingzhong

2016-02-01

A conceptual design and experiments, electrochemistry-flushing (E-flushing), using electrochemistry to enhance flushing efficiency for the remediation of Cr(Ⅵ)-contaminated soil is presented. The rector contained three compartments vertically superposed. The upper was airtight cathode compartment containing an iron-cathode. The middle was soil layer. The bottom was anode compartment containing an iron-anode and connected to a container by circulation pumps. H2 and OH(-) ions were produced at cathode. H2 increased the gas pressure in cathode compartment and drove flushing solution into soil layer forming flushing process. OH(-) ions entered into soil layer by eletromigration and hydraulic flow to enhance the desorption of Cr(Ⅵ). High potential gradient was applied to accelerate the electromigration of desorbed Cr(Ⅵ) ions and produced joule heat to increase soil temperature to enhance Cr(Ⅵ) desorption. In anode compartment, Fe(2+) ions produced at iron-anode reduced the desorbed Cr(Ⅵ) into Cr(3+) ions, which reacted with OH(-) ions forming Cr(OH)3. Experimental results show that Cr(Ⅵ) removal efficiency of E-flushing experiments was more than double of flushing experiments and reached the maximum of removal efficiency determined by desorption kinetics. All electrochemistry processes were positively used in E-flushing technology. Copyright © 2015 Elsevier Ltd. All rights reserved.

Novel electrical energy storage system based on reversible solid oxide cells: System design and operating conditions

NASA Astrophysics Data System (ADS)

Wendel, C. H.; Kazempoor, P.; Braun, R. J.

2015-02-01

Electrical energy storage (EES) is an important component of the future electric grid. Given that no other widely available technology meets all the EES requirements, reversible (or regenerative) solid oxide cells (ReSOCs) working in both fuel cell (power producing) and electrolysis (fuel producing) modes are envisioned as a technology capable of providing highly efficient and cost-effective EES. However, there are still many challenges and questions from cell materials development to system level operation of ReSOCs that should be addressed before widespread application. This paper presents a novel system based on ReSOCs that employ a thermal management strategy of promoting exothermic methanation within the ReSOC cell-stack to provide thermal energy for the endothermic steam/CO2 electrolysis reactions during charging mode (fuel producing). This approach also serves to enhance the energy density of the stored gases. Modeling and parametric analysis of an energy storage concept is performed using a physically based ReSOC stack model coupled with thermodynamic system component models. Results indicate that roundtrip efficiencies greater than 70% can be achieved at intermediate stack temperature (680 °C) and elevated stack pressure (20 bar). The optimal operating condition arises from a tradeoff between stack efficiency and auxiliary power requirements from balance of plant hardware.

Characterization of fine and carbonaceous particles emissions from pelletized biomass-coal blends combustion: Implications on residential crop residue utilization in China

NASA Astrophysics Data System (ADS)

Xu, Yue; Wang, Yan; Chen, Yingjun; Tian, Chongguo; Feng, Yanli; Li, Jun; Zhang, Gan

2016-09-01

Bulk biofuel, biomass pellets and pelletized biomass-coal blends were combusted in a typical rural conventional household stove and a high-efficiency stove. Reductions in PM2.5, organic carbon (OC) and elemental carbon (EC) emissions were evaluated by comparing emission factors (EFs) among 19 combinations of biofuel/residential stove types measured using a dilution sampling system. In the low-efficiency stove, the average EFs of PM2.5, OC, and EC of biomass pellets were 2.64 ± 1.56, 0.42 ± 0.36, and 0.30 ± 0.11 g/kg, respectively, significantly lower than those burned in bulk form. EFPM2.5 and EFOC of pelletized biomass combustion in the high-efficiency stove were lower than those of the same biofuel burned in the low-efficiency stove. Furthermore, pelletized corn residue and coal blends burned in the high-efficiency stove could significantly decrease emissions. Compared with the bulk material burned in the low-efficiency stove, the reduction rates of PM2.5, OC and EC from pelletized blends in the high-efficiency stove can reach 84%, 96% and 93%, respectively. If the annually produced corn residues in 2010 had been blended with 10% anthracite coal powder and burnt as pellets, it would have reduced about 82% of PM2.5, 90-96% of OC and 81-92% of EC emission in comparison with burning raw materials in conventional household stoves. Given the low cost, high health benefit and reduction effect on atmospheric pollutants, pelletized blends could be a promising alternative to fossil fuel resources or traditional bulk biofuel.

Major advances associated with reproduction in dairy cattle.

PubMed

Moore, K; Thatcher, W W

2006-04-01

The purpose of this overview is to review some of the major advances in reproductive technologies, and how they may be applied to meet the challenge of enhancing reproductive efficiency in the high-producing dairy cow of the 21st century. The current population of high-producing dairy cows is considered to be subfertile, as characterized by low pregnancy rates and high rates of embryonic mortality. Coordinated systems of reproductive management have been developed based upon a thorough understanding of the endocrine, cellular, and molecular factors controlling ovarian and uterine function. These systems will partially restore herd reproductive performance. Advances in other reproductive technologies offer possibilities for wider use of superior germplasm. Technologies such as sexed semen, cloning, transgenesis, and preimplantation genetic diagnosis offer the potential to enhance the influence of superior animals on production of food for human consumption. However, at this time, additional research is needed to counteract the higher rates of embryonic and fetal mortality associated with some of these technologies. Furthermore, use of genomics, proteomics, and bioinformatics in the study of reproduction will undoubtedly provide investigators with a greater understanding of the limitations to efficient reproductive processes in the subfertile lactating dairy cow.

Topologically guided tuning of Zr-MOF pore structures for highly selective separation of C6 alkane isomers

DOE PAGES

Wang, Hao; Dong, Xinglong; Lin, Junzhong; ...

2018-05-01

As an alternative technology to energy intensive distillations, adsorptive separation by porous solids offers lower energy cost and higher efficiency. Herein we report a topology-directed design and synthesis of a series of Zr-based metal-organic frameworks with optimized pore structure for efficient separation of C6 alkane isomers, a critical step in the petroleum refining process to produce gasoline with high octane rating. Zr 6O 4(OH) 4(bptc) 3 adsorbs a large amount of n-hexane but excluding branched isomers. The n-hexane uptake is ~70% higher than that of a benchmark adsorbent, zeolite-5A. A derivative structure, Zr 6O 4(OH) 8(H 2O) 4(abtc) 2, ismore » capable of discriminating all three C6 isomers and yielding a high separation factor for 3-methylpentane over 2,3-dimethylbutane. This property is critical for producing gasoline with further improved quality. Multicomponent breakthrough experiments provide a quantitative measure of the capability of these materials for separation of C6 alkane isomers. A detailed structural analysis reveals the unique topology, connectivity and relationship of these compounds.« less