Effect of water on sulfur dioxide (SO2) and nitrogen oxides (NOx) removal from flue gas in a direct current corona discharge reactor

NASA Astrophysics Data System (ADS)

Yang, Jiaxiang; Chi, Xiaochun; Dong, Limin

2007-05-01

A direct current (dc) corona discharge reactor composed of needle-plate electrodes in a glass container filled with flue gas was designed. To clarify the influence of water on discharge characteristics, water was introduced in the plasma reactor as electrode where plate electrode is immersed, under the application of dc voltage. Experiment results show that (1) corona wind forming between high-voltage needle electrode and water by corona discharge enhances the cleaning efficiency of flue gas due to the existence of water and the cleaning efficiency will increase with the increase of applied dc voltage within definite range and (2) both removal efficiencies of NOx and SO2 increased in the presence of water, which reach up to 98% for SO2, and about 85% for NOx under suitable conditions. These results play an important role in flue gas cleanup research.

Fully printed and integrated electrolyzer cells with additive manufacturing for high-efficiency water splitting

DOE PAGES

Yang, Gaoqiang; Mo, Jingke; Kang, Zhenye; ...

2018-02-20

Using additive manufacturing (AM) technology, a fundamental material and structure innovation was proposed to significantly increase the energy efficiency, and to reduce the weight, volume and component quantity of proton exchange membrane electrolyzer cells (PEMECs). Four conventional parts (liquid/gas diffusion layer, bipolar plate, gasket, and current distributor) in a PEMEC were integrated into one multifunctional AM plate without committing to tools or molds for the first time. In addition, since the interfacial contact resistances between those parts were eliminated, the comprehensive in-situ characterizations of AM cells showed that an excellent energy efficiency of up to 86.48% was achieved at 2more » A/cm2 and 80 degrees C, and the hydrogen generation rate was increased by 61.81% compared to the conventional cell. More importantly, the highly complex inner structures of the AM integrated multifunctional plates also exhibit the potential to break limitations of conventional manufacture methods for hydrogen generation and to open a door for the development of other energy conversion devices, including fuel cells, solar cells and batteries.« less

Fully printed and integrated electrolyzer cells with additive manufacturing for high-efficiency water splitting

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

Yang, Gaoqiang; Mo, Jingke; Kang, Zhenye

Using additive manufacturing (AM) technology, a fundamental material and structure innovation was proposed to significantly increase the energy efficiency, and to reduce the weight, volume and component quantity of proton exchange membrane electrolyzer cells (PEMECs). Four conventional parts (liquid/gas diffusion layer, bipolar plate, gasket, and current distributor) in a PEMEC were integrated into one multifunctional AM plate without committing to tools or molds for the first time. In addition, since the interfacial contact resistances between those parts were eliminated, the comprehensive in-situ characterizations of AM cells showed that an excellent energy efficiency of up to 86.48% was achieved at 2more » A/cm2 and 80 degrees C, and the hydrogen generation rate was increased by 61.81% compared to the conventional cell. More importantly, the highly complex inner structures of the AM integrated multifunctional plates also exhibit the potential to break limitations of conventional manufacture methods for hydrogen generation and to open a door for the development of other energy conversion devices, including fuel cells, solar cells and batteries.« less

76 FR 17577 - Increased Scope of Coverage for Electric Motors

Federal Register 2010, 2011, 2012, 2013, 2014

2011-03-30

... motors do not include a full frame, front plate, bearings, shaft, or shaft support. Because the ability.... chosen, the efficiency of these motors is therefore dependent on the application. Because of this, they... face plate, and therefore can be tested with a ``dummy test bracket'' using the current test procedure...

Preheating Water In The Covers Of Solar Water Heaters

NASA Technical Reports Server (NTRS)

Bhandari, Pradeep

1995-01-01

Solar water heaters that include glass covers over absorber plates redesigned to increase efficiencies according to proposal. Redesign includes modification of single-layer glass cover into double-layer glass cover and addition of plumbing so cool water to be heated made to flow between layers of cover before entering absorber plate.

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.

Improvements in Boron Plate Coating Technology for Higher Efficiency Neutron Detection and Coincidence Counting Error Reduction

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

Menlove, Howard Olsen; Henzlova, Daniela

This informal report presents the measurement data and information to document the performance of the advanced Precision Data Technology, Inc. (PDT) sealed cell boron-10 plate neutron detector that makes use of the advanced coating materials and procedures. In 2015, PDT changed the boron coating materials and application procedures to significantly increase the efficiency of their basic corrugated plate detector performance. A prototype sealed cell unit was supplied to LANL for testing and comparison with prior detector cells. Also, LANL had reference detector slabs from the original neutron collar (UNCL) and the new Antech UNCL with the removable 3He tubes. Themore » comparison data is presented in this report.« less

ENTRAINMENT AND EFFICIENCY STUDIES IN A SMALL DIAMETER BUBBLECAP PLATE COLUMN

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

Chrones, J.

1952-07-01

Efficiency and entrainment studies were made in a 4inch diameter bubblecap plate column using a plate spacing of 4 inches. The plates contained one bubblecap each, and were designed so taat they could be easily inserted in a single length of 4 inch OD stainless steel tubing. An entrainment of 10% was obtained for the water-steam system at a column vapor velocity of 1.9 fps or a vapor mass rate of 255 pounds of steam per hour per square foot. This entraimnent value is gener ally accepted as the maximum allowable without impairing the plate efficiency appreciably. This low entrainmentmore » may be partly due to the small column diameter with the walls acting as entrainanent separators. The Murphree vapor plate efficiency, as measured for alcohol-water, was found to depend on the slope of the equilibrium line and the mass velocity factor V / sub v//sup 0.5/. An empirical equation was developed relating these factors. Fow low values of the slope of the equilibrium line (2 or less it was noted, that for practical purposes, the actual point efficiency on the plates was equal to the measured Murphree vapor plate efficiency regardless of the degree of mixing on the plate. (auth)« less

Mechanisms Affecting Performance of the BaBar Resistive Plate Chambers and Searches for Remediation

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

Lu, Changguo

2003-09-19

The BaBar experiment at PEPII relies on the Instrumentation of the Flux Return (IFR) for both muon identification and KL detection. The active detector is composed of Resistive Plate Chambers (RPC's) operated in streamer mode. Since the start of operation the RPC's have suffered persistent efficiency deterioration and dark current increase problems. The ''autopsy'' of bad BaBar RPC's revealed that in many cases uncured Linseed oil droplets had formed on the inner surface of the Bakelite plates, leading to current paths from oil ''stalagmites'' bridging the 2 mm gap. In this paper a possible model of this ''stalagmite'' formation andmore » its effect on the dark current and efficiency of RPC chambers is presented. Laboratory test results strongly support this model. Based upon this model we are searching for solutions to eliminate the unfavorable effect of the oil stalagmites. The lab tests show that the stalagmite resistivity increases dramatically if exposed to the air, an observation that points to a possible way to remedy the damage and increase the efficiency. We have seen that flowing an oxygen gas mixture into the chamber helps to polymerize the uncured linseed oil. Consequently the resistivity of the bridged oil stalagmites increases, as does that of the oil coating on the frame edges and spacers, significantly reducing the RPC dark currents and low-efficiency regions. We have tested this idea on two chambers removed from BaBar because of their low efficiency and high dark current. These test results are reported in the paper, and two other remediation methods also mentioned. We continue to study this problem, and try to find new treatments with permanent improvement.« less

Heat transfer enhancement of flow insulator by combined stainless steel fibrous and wire net porous materials

NASA Astrophysics Data System (ADS)

Khantikomol, P.; Polsongkram, M.; Apisitpinyo, W.; Poowadin, T.

2018-01-01

The present research article aims to propose the heat transfer enhancement of the flow insulator using combined fibrous and wire net stainless steel porous material. The stainless fibrous plate with porosity of 0.9292 was combined to the stainless steel wire net having pore per inch (PPI) of 16 and total thickness of 30 mm. Two models of the arranging porous plates were prepared, which were model BA and model AB. Each porous plate segment had the same thickness. The examined porous plate model have porosities of 0.8452. The porous plate was placed normal to the flow direction. The air was used as working fluid heated by 5 kW electric heater, which was controlled by the automatic temperature control. Type-K thermocouples were employed to measure the air temperatures. The temperature at front of the porous plate was varied to be 350, 450, and 550°C. The air flow rate was varied in the range of 4-12 m3/hr. The experimental result showed that the temperature drop across the porous plate and the thermal efficiency increase with the inlet temperature. The air velocity slightly affects the temperature profile inside the test section at the upstream side of the porous plate but greatly affects temperature inside the porous plate. In consideration of the arranging porous plate, placing of the stainless steel wire net at the upstream side and placing the stainless steel fibrous at downstream side (model BA) results in the highest temperature drop and the highest thermal efficiency. At Re 733 and inlet temperature 550°C for model BA at 30 mm thickness, the thermal efficiency was 50%. It was shown that the combined stainless steel fibrous and stainless steel wire net porous material could be a good flow insulator.

An experimental investigation with artificial sunlight of a solar hot-water heater

NASA Technical Reports Server (NTRS)

Simon, F. F.

1976-01-01

Thermal performance measurements were made of a commercial solar hot-water heater in a solar simulator. The objective of the test was to determine basic performance characteristics of a traditional type of flat-plate collector, with and without side reflectors (to increase the solar flux). Due to the fact that collector testing in the solar simulator permits control of the variables that affect collector performance, it was possible to obtain information on each of the following: (1) the effect of flow and incidence angle on the efficiency of a flat-plate collector (but only without side reflectors), (2) transient performance under flow and nonflow conditions, (3) the effectiveness of reflectors in increasing collector efficiency for a zero radiation angle at fluid temperatures required for solar air conditioning, and (4) the limits of applicability of a collector efficiency correlation based on the Hottel-Whillier equation (1958).

Electrospun polyvinyl alcohol ultra-thin layer chromatography of amino acids.

PubMed

Lu, Tian; Olesik, Susan V

2013-01-01

Electrospun polyvinyl alcohol (PVA) ultrathin layer chromatographic (UTLC) plates were fabricated using in situ crosslinking electrospinning technique. The value of these ULTC plates were characterized using the separation of fluorescein isothiocyanate (FITC) labeled amino acids and the separation of amino acids followed visualization using ninhydrin. The in situ crosslinked electrospun PVA plates showed enhanced stability in water and were stable when used for the UTLC study. The selectivity of FITC labeled amino acids on PVA plate was compared with that on commercial Si-Gel plate. The efficiency of the separation varied with analyte concentration, size of capillary analyte applicator, analyte volume, and mat thickness. The concentration of 7mM or less, 50μm i.d. capillary applicator, minimum volume of analyte solution and three-layered mat provides the best efficiency of FITC-labeled amino acids on PVA UTLC plate. The efficiency on PVA plate was greatly improved compared to the efficiency on Si-Gel HPTLC plate. The hydrolysis products of aspartame in diet coke, aspartic acid and phenylalanine, were also successfully analyzed using PVA-UTLC plate. Copyright © 2012 Elsevier B.V. All rights reserved.

The constraint method: A new finite element technique. [applied to static and dynamic loads on plates

NASA Technical Reports Server (NTRS)

Tsai, C.; Szabo, B. A.

1973-01-01

An approch to the finite element method which utilizes families of conforming finite elements based on complete polynomials is presented. Finite element approximations based on this method converge with respect to progressively reduced element sizes as well as with respect to progressively increasing orders of approximation. Numerical results of static and dynamic applications of plates are presented to demonstrate the efficiency of the method. Comparisons are made with plate elements in NASTRAN and the high-precision plate element developed by Cowper and his co-workers. Some considerations are given to implementation of the constraint method into general purpose computer programs such as NASTRAN.

Design and development of a chopping and deflecting system for the high current injector at IUAC

NASA Astrophysics Data System (ADS)

Kedia, Sanjay Kumar; Mehta, R.

2018-05-01

The Low Energy Beam Transport (LEBT) section of the High Current Injector (HCI) incorporates a Chopping cum Deflecting System (CDS). The CDS comprises of a deflecting system and a pair of slits that will remove dark current and produce time bunched beam of 60 ns at different repetition rates of 4, 2, 1, 0.5, 0.25 and 0.125 MHz. The distinguishing feature of the design is the use of a multi-plate deflecting structure with low capacitance to optimize the electric field, which in turn results in higher efficiency in terms of achievable ion current. To maximize the effective electric field and its uniformity, the gap between the deflecting plates has been varied and a semi-circular contour has been incorporated on the deflecting plates. Due to this the electric field variation is less than ±0.5% within the plate length. The length of deflecting plates was chosen to maximize the transmission efficiency. Since the velocity of the charged particles in the LEBT section is constant, therefore the separation between two successive sets of deflecting plates has been kept constant to match the ions transient time within the gap which is nearly 32 ns. A square pulse has been chosen, instead of a sinusoidal one, to increase the transmission efficiency and to decrease the tailing effect. The loaded capacitance of the structure was kept <10 pF to achieve fast rise/fall time of the applied voltage signal. A Python code has been developed to verify the various design parameters. The simulation also shows that one can get an efficient deflection of undesired particles resulting in >90% transmission efficiency with in the bunch length. Various simulation codes like Solid Works, TRACE 3D, CST MWS and homebrew Python codes were used to validate the design.

Efficiency enhancement of ZnO nanostructure assisted Si solar cell based on fill factor enlargement and UV-blue spectral down-shifting

NASA Astrophysics Data System (ADS)

Gholizadeh, A.; Reyhani, A.; Parvin, P.; Mortazavi, S. Z.

2017-05-01

ZnO nanostructures (including nano-plates and nano-rods (NRs)) are grown in various temperatures and Ar/O2 flow rates using thermal chemical vapor deposition, which affect the structure, nano-plate/NR population, and the quality of ZnO nanostructures. X-ray diffraction (XRD) attests that the peak intensity of the crystallographic plane (1 0 0) is correlated to nano-plate abundance. Moreover, optical properties elucidate that the population of nano-plates in samples strongly affect the band gap, binding energy of the exciton, and UV-visible (UV-vis) absorption and spectral luminescence emissions. In fact, the exciton binding energy reduces from ~100 to 80 meV when the population of nano-plates increases in samples. Photovoltaic characteristics based on the drop-casting on Si solar cells reveals three dominant factors, namely, the equivalent series resistance, decreasing reflectance, and down-shifting, in order to scale up the absolute efficiency by 3%. As a consequence, the oxygen vacancies in ZnO nanostructures give rise to the down-shifting and increase of free-carriers, leading to a reduction in the equivalent series resistance and an enlargement of fill factor. To obtain a larger I sc, reduction of spectral reflectance is essential; however, the down-shifting process is shown to be dominant by lessening the surface electron-hole recombination rate over the UV-blue spectral range.

Enhanced methanol utilization in direct methanol fuel cell

DOEpatents

Ren, Xiaoming; Gottesfeld, Shimshon

2001-10-02

The fuel utilization of a direct methanol fuel cell is enhanced for improved cell efficiency. Distribution plates at the anode and cathode of the fuel cell are configured to distribute reactants vertically and laterally uniformly over a catalyzed membrane surface of the fuel cell. A conductive sheet between the anode distribution plate and the anodic membrane surface forms a mass transport barrier to the methanol fuel that is large relative to a mass transport barrier for a gaseous hydrogen fuel cell. In a preferred embodiment, the distribution plate is a perforated corrugated sheet. The mass transport barrier may be conveniently increased by increasing the thickness of an anode conductive sheet adjacent the membrane surface of the fuel cell.

Physical and chemical analysis of a Ni/H2 cell

NASA Technical Reports Server (NTRS)

Vaidyanathan, H.; Earl, M. W.; Kirkendall, T. D.

1991-01-01

A cycled aerospace nickel hydrogen (Ni/H2) cell was subjected to destructive physical analysis to determine the reason for a capacity loss after 5,967 cycles at 60 percent depth of discharge. The positive plates in the cell were analyzed in terms of chemical composition, active material utilization, charge efficiency, and thickness increase. The microstructure of a cross section of the positive plate was determined by backscattered electron image analysis. The results suggest that the capacity loss in the cell is caused by low charge acceptance and low active material utilization at the positive plate. The oxidized nickel species content of the positive plate increased due to corrosion of the nickel sintered skeleton. This appears to circumvent the orderly reaction of the active material. Microstructural analysis has indicated that a new phase of active material is formed with cycling.

Killing of Bacillus Megaterium Spores by X-rays at the Phosphorus K-edge

NASA Technical Reports Server (NTRS)

Richmond, Robert C.; Frigo, Sean P.; Ehret, Charles F.; Rose, M. Franklin (Technical Monitor)

2001-01-01

This study continues a progression of experiments on the radiation-induced killing of bacterial spores that began at the Argonne National Laboratory in 1957. A series of aliquots of Bacillus megaterium spores were prepared onto polycarbonate filters and irradiated with photons of 2159 eV compared to 2140 eV energy on the 2-IDB beamline at the Advanced Photon Source. Flux density was approximately 10(exp 18) photons/sec/sq mm. The phosphorous K-edge absorption spectrum in these spores was determined to peak at 2159 eV, wheras 2140 eV was determined to be outside that absorption spectrum. Spores on filters were irradiated at ambient conditions, and were either immediately plated for colony formation after irradiation, or were held for postirradiation exposure to oxygen prior to plating. Slopes of survival curves from the four conditions of irradiation, i.e., two photon energies each comparing immediate plating vs postirradiation holding, were used for quantitative determination of differences in rates of spore killing over a range of radiation doses. It was found that spores irradiated at the phosphorus K-edge were killed 20% more efficiently than when irradiated with 2140 eV photons, and this was true for both immediate plating and postirradiation holding in air. Postirradiation holding in air increased killing efficiency by about 12% for both photon energies compared to plating immediately after irradiation. The increase of killing efficiency with postirradiation holding is less than expected from earlier experiments using relatively low-flux X-rays, and raises the possibility of dose-mitigation by radical-radical recombination in the case of high-flux X-rays from the synchrotron.

Killing of Bacillus Megaterium Spores by X-Rays at the Phosphorus K-Edge

NASA Technical Reports Server (NTRS)

Richmond, Robert C.; Frigo, Sean P.; Ehret, Charles F.; Rose, M. Franklin (Technical Monitor)

2001-01-01

This study continues a progression of experiments on the radiation-induced killing of bacterial spores that began at the Argonne National Laboratory in 1957. A series of aliquots of Bacillus megaterium spores were prepared onto polycarbonate filters and irradiated with photons of 2159 eV compared to 2140 eV energy on the 2-IDB beamline at the Advanced Photon Source. Flux density was approximately 10 photons/sec/mm . The phosphorous K-edge absorption spectrum in these spores was determined to peak at 2159 eV, wheras 2140 eV was determined to be outside that absorption spectrum. Spores on filters were irradiated at ambient conditions, and were either immediately plated for colony formation after irradiation, or were held for postirradiation exposure to oxygen prior to plating. Slopes of survival curves from the four conditions of irradiation, i.e., two photon energies each comparing immediate plating vs postirradiation holding, were used for quantitative determination of differences in rates of spore killing over a range of radiation doses. It was found that spores irradiated at the phosphorus K-edge were killed 20% more efficiently than when irradiated with 2140eV photons, and this was true for both immediate plating and postirradiation holding in air. Postirradiation holding in air increased killing efficiency by about 12% for both photon energies compared to plating immediately after irradiation. The increase of killing efficiency with postirradiation holding is less than expected from earlier experiments using relatively low-flux X-rays, and raises the possibility of dose-mitigation by radical-radical recombination in the case of high-flux X-rays from the synchrotron.

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.

Electroviscous effect and electrokinetic energy conversion in time periodic pressure-driven flow through a parallel-plate nanochannel with surface charge-dependent slip

NASA Astrophysics Data System (ADS)

Buren, Mandula; Jian, Yongjun; Zhao, Yingchun; Chang, Long

2018-05-01

In this paper we analytically investigate the electroviscous effect and electrokinetic energy conversion in the time periodic pressure-driven flow of an incompressible viscous Newtonian liquid through a parallel-plate nanochannel with surface charge-dependent slip. Analytical and semi-analytical solutions for electric potential, velocity and streaming electric field are obtained and are utilized to compute electrokinetic energy conversion efficiency. The results show that velocity amplitude and energy conversion efficiency are reduced when the effect of surface charge on slip length is considered. The surface charge effect increases with zeta potential and ionic concentration. In addition, the energy conversion efficiency is large when the ratio of channel half-height to the electric double layer thickness is small. The boundary slip results in a large increase in energy conversion. Higher values of the frequency of pressure pulsation lead to higher values of the energy conversion efficiency. We also obtain the energy conversion efficiency in constant pressure-driven flow and find that the energy conversion efficiency in periodical pressure-driven flow becomes larger than that in constant pressure-driven flow when the frequency is large enough.

Influence of wire-coil inserts on the thermo-hydraulic performance of a flat-plate solar collector

NASA Astrophysics Data System (ADS)

Herrero Martín, R.; García, A.; Pérez-García, J.

2012-11-01

Enhancement techniques can be applied to flat-plate liquid solar collectors towards more compact and efficient designs. For the typical operating mass flow rates in flat-plate solar collectors, the most suitable technique is inserted devices. Based on previous studies from the authors, wire coils were selected for enhancing heat transfer. This type of inserted device provides better results in laminar, transitional and low turbulence fluid flow regimes. To test the enhanced solar collector and compare with a standard one, an experimental side-by-side solar collector test bed was designed and constructed. The testing set up was fully designed following the requirements of EN12975-2 and allow us to accomplish performance tests under the same operating conditions (mass flow rate, inlet fluid temperature and weather conditions). This work presents the thermal efficiency curves of a commercial and an enhanced solar collector, for the standardized mass flow rate per unit of absorber area of 0.02 kg/sm2 (in useful engineering units 144 kg/h for water as working fluid and 2 m2 flat-plate solar collector of absorber area). The enhanced collector was modified inserting spiral wire coils of dimensionless pitch p/D = 1 and wire-diameter e/D = 0.0717. The friction factor per tube has been computed from the overall pressure drop tests across the solar collectors. The thermal efficiency curves of both solar collectors, a standard and an enhanced collector, are presented. The enhanced solar collector increases the thermal efficiency by 15%. To account for the overall enhancement a modified performance evaluation criterion (R3m) is proposed. The maximum value encountered reaches 1.105 which represents an increase in useful power of 10.5% for the same pumping power consumption.

Effect of fly ash on catalytic removal of gaseous dioxins over V{sub 2}O{sub 5}-WO{sub 3} catalyst of a sinter plant

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

Shu Hao Chang; Kai Hsien Chi; Chi Wei Young

2009-10-01

A PCDD/F (polychlorinated dibenzo-p-dioxin and dibenzofuran)-containing gas stream generating system was developed to investigate the efficiency and effectiveness of V{sub 2}O{sub 5}-WO{sub 3} catalyst for PCDD/F destruction. Catalytic decomposition of PCDD/Fs (simulated gas streams) was evaluated with lab-scale pelletized and plate-type catalyst based on V{sub 2}O{sub 5}-WO{sub 3}/TiO{sub 2} at controlled temperature, space velocity, and inlet PCDD/F concentration. Due to the lower porosity of the pelletized catalyst, PCDD/F destruction efficiencies reach 72.9-83.2% for different levels of inlet PCDD/F concentrations (1.08-3.04 ng-TEQ/Nm{sup 3}) of the gas stream (space velocity: 5000 h-1). As the surface area is increased from 287 m{sup 2}/m{supmore » 3} (plate-type A) to 550 m{sup 2}/m{sup 3} (plate-type B), the PCDD/F destruction achieved with plate-type catalyst increases from 76.0% to 85.3% at 320{sup o}C (space velocity: 5000 h{sup -1}). In addition, the results of pilot-scale experiment (real flue gases of a sinter plant) indicate that relatively lower PCDD/F destruction efficiencies (62.1-65.7%) were achieved with the plate-type B catalyst as the solid-phase PCDD/F and fly ash passed through the reactor (space velocity: 5000 h{sup -1}). Overall, the lab-scale and pilot-scale experiments indicate that PCDD/F destructions achieved with pelletized and plate-type catalysts strongly depend on the operating temperature of the catalyst. The results also indicate that the presence of fly ash lowers PCDD/F destruction due to significant PCDD/F formation via de novo synthesis at 320{sup o}C. 20 refs., 5 figs., 3 tabs.« less

Quality Improvement of Chrome-Diamond Coatings on Flowing Chrome Plating

NASA Astrophysics Data System (ADS)

Belyaev, V. N.; Koslyuk, A. Yu; Lobunets, A. V.; Andreyev, A. S.

2016-04-01

The research results of the process of flowing chrome plating of internal surfaces of long-length cylindrical articles with the usage of electrolyte with ultra-dispersed diamonds when continuous article rotation, while chromium-plating, are presented. During experiments the following varying technological parameters: electrolyte temperature and article frequency rotation were chosen, and experimental samples were obtained. Estimation of porosity, micro-hardness, thickness of chrome coatings and uniformity were performed as well as the precipitation structure by the method of scanning electron microscopy. The results showed that the use of ultra-dispersed diamonds and realization of the scheme with rotation of detail-cathode when flowing chromium-plating allows one to increase servicing characteristics of the coating due to the decrease of grains size of chrome coating and porosity, and due to the increase of micro-hardness, so confirming the efficiency of using the suggested scheme of coating application and the given type of ultra-dispersed fillers when chromium-plating.

Corrosion resistance and mechanical properties of titanium nitride plating on orthodontic wires.

PubMed

Sugisawa, Haruki; Kitaura, Hideki; Ueda, Kyosuke; Kimura, Keisuke; Ishida, Masahiko; Ochi, Yumiko; Kishikawa, Akiko; Ogawa, Saika; Takano-Yamamoto, Teruko

2018-03-30

Titanium nitride (TiN) coating by ion plating has properties such as high hardness, wear resistance, corrosion resistance, and surface lubricity, therefore TiN coating is often used in various dental appliances and materials. In this study, we evaluated the corrosion behaviors and mechanical properties of TiN coated stainless steel (SS) and nickel titanium (Ni-Ti) orthodontic wires prepared by ion plating. TiN coating by ion plating improves the corrosion resistance of orthodontic wires. The corrosion pitting of the TiN coated wire surface become small. The tensile strength and stiffness of SS wire were increased after TiN coating. In contrast, its elastic force, which is a property for Ni-Ti wire, was decreased. In addition, TiN coating provided small friction forces. The low level of friction may increase tooth movement efficiently. Therefore, TiN coated SS wire could be useful for orthodontics treatment.

SAMI Automated Plug Plate Configuration

NASA Astrophysics Data System (ADS)

Lorente, N. P. F.; Farrell, T.; Goodwin, M.

2013-10-01

The Sydney-AAO Multi-object Integral field spectrograph (SAMI) is a prototype wide-field system at the Anglo-Australian Telescope (AAT) which uses a plug-plate to mount its 13×61-core imaging fibre bundles (hexabundles) in the optical path at the telescope's prime focus. In this paper we describe the process of determining the positions of the plug-plate holes, where plates contain three or more stacked observation configurations. The process, which up until now has involved several separate processes and has required significant manual configuration and checking, is now being automated to increase efficiency and reduce error. This is carried out by means of a thin Java controller layer which drives the configuration cycle. This layer controls the user interface and the C++ algorithm layer where the plate configuration and optimisation is carried out. Additionally, through the Aladin display package, it provides visualisation and facilitates user verification of the resulting plates.

Shelter effect efficacy of sand fences: A comparison of systems in a wind tunnel

NASA Astrophysics Data System (ADS)

Wang, Tao; Qu, Jianjun; Ling, Yuquan; Liu, Benli; Xiao, Jianhua

2018-02-01

The Lanzhou-Xinjiang High-speed Railway runs through an expansive wind area in the Gobi Desert and blown-sand disasters are a critical issue affecting its operation. To strengthen the blown-sand disaster shelter systems along the railway, the shelter effects of punching plate and wire mesh fences with approximately equal porosity (48%) were simulated in a wind tunnel. The experimental results showed that the wind velocity was reduced to a higher extent by the punching plate fence than by the wire mesh fence. When a single row of sand fencing was used, the wind velocity reduction coefficient (Rcz) values downwind of the punching plate fence and wire mesh fence reached 71.77% and 39.37%, respectively. When double rows of sand fencing were used, the Rcz values downwind of the punching plate and wire mesh fences were approximately 87.48% and 60.81%, respectively. For the flow field structure on the leeward side of the fencing, the deceleration zone behind the punching plate fence was more pronounced than that behind the wire mesh fence. The vortex zone was not obvious and the reverse flow disappeared for both types of fences, which indicates that the turbulent intensity was small. The sand-trapping efficiency of the wire mesh fence was close to that of punching plate fence. When a single row of sand fencing was set up, the total mass flux density decreased, on average, by 65.85% downwind of the wire mesh fence, and 75.06% downwind of the punching plate fence; when double rows of sand fencing were present, the total mass flux density decreased, on average, by 84.53% downwind of the wire mesh fence and 84.51% downwind of the punching plate fence. In addition, the wind-proof efficiency and the sand-proof efficiency of the punching plate fence and the wire mesh fence decreased with increasing wind velocities. Consequently, punching plate and wire mesh fences may effectively control the sand hazard in the expansive wind area of the Gobi Desert.

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.

Separation of natural product using columns packed with Fused-Core particles.

PubMed

Yang, Peilin; Litwinski, George R; Pursch, Matthias; McCabe, Terry; Kuppannan, Krishna

2009-06-01

Three HPLC columns packed with 3 microm, sub-2 microm, and 2.7 microm Fused-Core (superficially porous) particles were compared in separation performance using two natural product mixtures containing 15 structurally related components. The Ascentis Express C18 column packed with Fused-Core particles showed an 18% increase in column efficiency (theoretical plates), a 76% increase in plate number per meter, a 65% enhancement in separation speed and a 19% increase in back pressure compared to the Atlantis T3 C18 column packed with 3 microm particles. Column lot-to-lot variability for critical pairs in the natural product mixture was observed with both columns, with the Atlantis T3 column exhibiting a higher degree of variability. The Ascentis Express column was also compared with the Acquity BEH column packed with sub-2 microm particles. Although the peak efficiencies obtained by the Ascentis Express column were only about 74% of those obtained by the Acquity BEH column, the 50% lower back pressure and comparable separation speed allowed high-efficiency and high-speed separation to be performed using conventional HPLC instrumentation.

Removal of NO and SO2 in Corona Discharge Plasma Reactor with Water Film

NASA Astrophysics Data System (ADS)

He, Yuanji; Dong, Liming; Yang, Jiaxiang

2004-04-01

In this paper, a novel type of a corona discharge plasma reactor was designed, which consists of needle-plate-combined electrodes, in which a series of needle electrodes are placed in a glass container filled with flue gas, and a plate electrode is immersed in the water. Based on this model, the removal of NO and SO2 was tested experimentally. In addition, the effect of streamer polarity on the reduction of SO2 and NO was investigated in detail. The experimental results show that the corona wind formed between the high-voltage needle electrode and the water by corona discharge enhances the cleaning efficiency of the flue gas because of the presence of water, and the cleaning efficiency will increase with the increase of applied dc voltage within a definite range. The removal efficiency of SO2 up to 98%, and about 85% of NOx removal under suitable conditions is obtained in our experiments.

Effect of geometric and process variables on the performance of inclined plate settlers in treating aquacultural waste.

PubMed

Sarkar, Sudipto; Kamilya, Dibyendu; Mal, B C

2007-03-01

Inclined plate settlers are used in treating wastewater due to their low space requirement and high removal rates. The prediction of sedimentation efficiency of these settlers is essential for their performance evaluation. In the present study, the technique of dimensional analysis was applied to predict the sedimentation efficiency of these inclined plate settlers. The effect of various geometric parameters namely, distance between plates (w(p)), plate angle (alpha), length of plate (l(p)), plate roughness (epsilon(p)), number of plates (n(p)) and particle diameter (d(s)) on the dynamic conditions, influencing the sedimentation process was studied. From the study it was established that neither the Reynolds criterion nor the Froude criterion was singularly valid to simulate the sedimentation efficiency (E) for different values of w(p) and flow velocity (v(f)). Considering the prevalent scale effect, simulation equations were developed to predict E at different dynamic conditions. The optimum dynamic condition producing the maximum E is also discussed.

Laser Cutting of Multilayered Kevlar Plates

NASA Astrophysics Data System (ADS)

Yilbas, B. S.; Al-Sulaiman, F.; Karakas, C.; Ahsan, M.

2007-12-01

Laser cutting of Kevlar plates, consisting of multilayered laminates, with different thicknesses are carried out. A mathematical model is developed to predict the kerf width, thermal efficiency, and specific energy requirements during cutting. Optical microscopy and Scanning Electron Microscopy (SEM) are employed to obtain the micrographs of the cutting sections. The kerf width size is measured and compared with the predictions. A factorial analysis is carried out to assess the affecting parameters on the mean kerf width and dimensionless damage sizes. It is found that the kerf width and damage sizes changes sharply when increasing cutting speed from 0.03 to 0.08 m/s. Thermal efficiency of the cutting process increases with increasing thickness and cutting speed while specific energy reduces with increasing thickness. The main effects of cutting parameters are found to be significant on the mean kerf width and dimensionless damage sizes, which is more pronounced for the workpiece bottom surface, where locally distributed char formation and sideways burning are observed.

Chromatic characterization of ion-exchanged glass binary phase plates for mode-division multiplexing.

PubMed

Prieto-Blanco, Xesús; Montero-Orille, Carlos; Moreno, Vicente; Mateo, Eduardo F; Liñares, Jesús

2015-04-10

Mode-division multiplexing (MDM) in few-mode fibers is regarded as a promising candidate to increase optical network capacity. A fundamental element for MDM is a modal transformer to LP modes which can be implemented in a free-space basis by using multiregion phase plates, that is, LP plates. Likewise, several wavelengths have to be used due to wavelength multiplexing purposes, optical amplification tasks, and so on. In this work we show that efficient monolithic binary phase plates for different wavelengths can be fabricated by ion-exchange in glass and used for MDM tasks. We introduce an optical characterization method of the chromatic properties of such phase plates which combines the inverse Wentzel-Kramers-Brillouin (IWKB) together with Mach-Zehnder and Michelson-based interferometric techniques. The interferometric method provides a measurement of the phase step for several wavelengths, which characterizes the chromatic properties of the phase plate. Consequently, it is shown that the IWKB method allows us to design and characterize the phase plates in an easy and fast way.

Investigation of the decolorization efficiency of two pin-to-plate corona discharge plasma system for industrial wastewater treatment

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

El-Tayeb, A., E-mail: ahmed.khalil@ejust.edu.eg; El-Shazly, A. H.; Elkady, M. F.

In this article, a dual pin-to-plate high-voltage corona discharge system is introduced to study experimentally the gap distance, the contact time, the effect of pin and plate materials, the thickness of ground plate and the conductivity on the amount of Acid Blue 25 dye color removal efficiency from polluted water. A study for the optimum air gap distance between dual pin and surface of Acid Blue 25 dye solution is carried out using 3D-EM simulator to find maximum electric field intensity at the tip of both pins. The outcomes display that the best gap for corona discharge is approximately 5more » mm for 15-kV source. This separation is constant during the study of other factors. In addition, an investigation of the essential reactive species responsible for oxidation of the dye organic compounds (O{sub 3} in air discharge, O{sub 3} in water, and H{sub 2}O{sub 2}) during the experimental time is conducted. Three various materials such as: stainless steel, copper and aluminum are used for pins and plate. The maximum color removal efficiencies of Acid Blue 25 dyes are 99.03, 82.04, and 90.78% after treatment time 15 min for stainless steel, copper, and aluminum, respectively. Measurement results for the impact of thickness of an aluminum ground plate on color removal competence show color removal efficiencies of 86.3, 90.78, and 98.06% after treatment time 15 min for thicknesses of 2, 0.5, and 0.1 mm, respectively. The increasing of the solution conductivity leads to the reduction of decolorization efficiency. A kinetic model is used to define the performance of corona discharge system. The models of pseudo-zero-order, pseudo-first-order, and pseudo-second-order reaction kinetics are utilized to investigate the decolorization of Acid Blue 25 dye. The rate of degradation of Acid Blue 25 dye follows the pseudo-first-order kinetics in the dye concentration.« less

Effects of oil on the feeding mechanism of the bowhead whale. Final report

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

Braithwaite, L.F.

1983-06-10

Research was designed to determine the effect of crude oil on the filtration efficiency of bowhead whale (Balaena mysticetus) baleen. An experiment apparatus was constructed with temperature-controlled, circulating sea water moving through a chamber containing mounted baleen plates. All circulating water of the apparatus flowed over and through the hair-fringed stratum of the baleen plates. Efficiency of filtration of living plankters was measured and compared for various kinds and levels of petroleum fouling. The filtering efficiency of the baleen plates decreased when the plates were fouled with Prudhoe Bay crude oil.

Development of zinc-plated regenerator material

NASA Astrophysics Data System (ADS)

Y Xu, M.; Morie, T.; Tsuchiya, A.

2017-12-01

An effective way to improve the efficiency of a cryocooler is to improve the efficiency of the regenerator. In general, the heat capacity of materials decreases as temperature decreases. Thus, when temperature is below 40 K, lead or bismuth spheres are often used as regenerator materials. However, the pressure drop in a sphere regenerator is much larger than that in a screen regenerator. To overcome this dilemma, Xu et al. reported that cooling performance at the temperature of less than 40 K was improved when using tin-plated screens at the cold end of the regenerator. However, the reliability of tin at low temperatures is still not verified fully because of its phase transition from a normal β phase to an abnormal α phase, which may result in a significant reduction of the mechanical strength. In this paper, a zinc-plated screen is proposed as another potential alternative. A comparison test was performed with a two-stage GM cryocooler by replacing part of the first stage regenerator material, phosphorus bronze screens, with zinc-plated screens. Compared to a regenerator filled with bronze screens, the cooling capacity of the first stage increased by about 11% at 40 K and 60% at 30 K with these zinc-plated screens. The detailed experimental results are reported in this paper.

Induction-heating MOCVD reactor with significantly improved heating efficiency and reduced harmful magnetic coupling

NASA Astrophysics Data System (ADS)

Li, Kuang-Hui; Alotaibi, Hamad S.; Sun, Haiding; Lin, Ronghui; Guo, Wenzhe; Torres-Castanedo, Carlos G.; Liu, Kaikai; Valdes-Galán, Sergio; Li, Xiaohang

2018-04-01

In a conventional induction-heating III-nitride metalorganic chemical vapor deposition (MOCVD) reactor, the induction coil is outside the chamber. Therefore, the magnetic field does not couple with the susceptor well, leading to compromised heating efficiency and harmful coupling with the gas inlet and thus possible overheating. Hence, the gas inlet has to be at a minimum distance away from the susceptor. Because of the elongated flow path, premature reactions can be more severe, particularly between Al- and B-containing precursors and NH3. Here, we propose a structure that can significantly improve the heating efficiency and allow the gas inlet to be closer to the susceptor. Specifically, the induction coil is designed to surround the vertical cylinder of a T-shaped susceptor comprising the cylinder and a top horizontal plate holding the wafer substrate within the reactor. Therefore, the cylinder coupled most magnetic field to serve as the thermal source for the plate. Furthermore, the plate can block and thus significantly reduce the uncoupled magnetic field above the susceptor, thereby allowing the gas inlet to be closer. The results show approximately 140% and 2.6 times increase in the heating and susceptor coupling efficiencies, respectively, as well as a 90% reduction in the harmful magnetic flux on the gas inlet.

More are better, but the details matter: combinations of multiple Fresnel zone plates for improved resolution and efficiency in X-ray microscopy

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

Li, Kenan; Jacobsen, Chris

Fresnel zone plates used for X-ray nanofocusing face high-aspect-ratio nanofabrication challenges in combining narrow transverse features (for high spatial resolution) along with extended optical modulation along the X-ray beam direction (to improve efficiency). The stacking of multiple Fresnel zone plates along the beam direction has already been shown to offer improved characteristics of resolution and efficiency when compared with thin single zone plates. Using multislice wave propagation simulation methods, here a number of new schemes for the stacking of multiple Fresnel zone plates are considered. These include consideration of optimal thickness and spacing in the axial direction, and methods tomore » capture a fraction of the light otherwise diffracted into unwanted orders, and instead bring it into the desired first-order focus. In conclusion, the alignment tolerances for stacking multiple Fresnel zone plates are also considered.« less

Alternative Fuels Data Center

Science.gov Websites

AFV special license plate, which are available from the Arizona Department of Transportation (ADOT license plate. ADOT has reached its maximum limit of 10,000 vehicles and the issuance of Energy Efficient Alternative Fuel Vehicle (AFV) and Energy Efficient Plate Programs Dedicated AFVs qualify for an

Periodic nanostructures formed on a poly-methyl methacrylate surface with a femtosecond laser for biocompatibility improvement

NASA Astrophysics Data System (ADS)

Takenaka, Keisuke; Tsukamoto, Masahiro; Sato, Yuji; Ooga, Takahiro; Asai, Satoru; Murai, Kensuke

2018-06-01

Poly(methyl methacrylate) (PMMA) is widely used as a biomaterial. The formation of periodic nanostructures on the surface is necessary to improve the biocompatibility. A method was proposed and developed to form periodic nanostructures on a PMMA surface. A PMMA plate was placed on titanium (Ti) plate, and then the Ti plate was irradiated with a laser through the PMMA plate. We try to effectively produce periodic nanostructures on PMMA with a femtosecond laser at a fundamental wavelength by increasing the contact pressure and using titanium (Ti) plate. The contact pressure between PMMA and Ti required to form a periodic nanostructure is 300 kPa, and for a contact pressure of 2400 kPa, periodic nanostructures are formed in 62% of the laser-irradiated area on the PMMA surface. These results suggest that the formation efficiency of the periodic nanostructure depends on the laser conditions and the contact pressure.

High-aspect ratio zone plate fabrication for hard x-ray nanoimaging

NASA Astrophysics Data System (ADS)

Parfeniukas, Karolis; Giakoumidis, Stylianos; Akan, Rabia; Vogt, Ulrich

2017-08-01

We present our results in fabricating Fresnel zone plate optics for the NanoMAX beamline at the fourth-generation synchrotron radiation facility MAX IV, to be used in the energy range of 6-10 keV. The results and challenges of tungsten nanofabrication are discussed, and an alternative approach using metal-assisted chemical etching (MACE) of silicon is showcased. We successfully manufactured diffraction-limited zone plates in tungsten with 30 nm outermost zone width and an aspect ratio of 21:1. These optics were used for nanoimaging experiments at NanoMAX. However, we found it challenging to further improve resolution and diffraction efficiency using tungsten. High efficiency is desirable to fully utilize the advantage of increased coherence on the optics at MAX IV. Therefore, we started to investigate MACE of silicon for the nanofabrication of high-resolution and high-efficiency zone plates. The first type of structures we propose use the silicon directly as the phase-shifting material. We have achieved 6 μm deep dense vertical structures with 100 nm linewidth. The second type of optics use iridium as the phase material. The structures in the silicon substrate act as a mold for iridium coating via atomic layer deposition (ALD). A semi-dense pattern is used with line-to-space ratio of 1:3 for a so-called frequency-doubled zone plate. This way, it is possible to produce smaller structures with the tradeoff of the additional ALD step. We have fabricated 45 nm-wide and 3.6 μm-tall silicon/iridium structures.

Reactive conductors for increased efficiency of exploding foil initiators and other detonators

DOEpatents

Morris, Christopher J.; Wilkins, Paul; May, Chadd; Zakar, Eugene

2015-05-05

Provided among other things are reactive energetic material systems used for conductors in detonators for increased efficiencies. According to an embodiment, a detonator may include: a conductor including at least two constituents including (i) an electrically conductive constituent, and (ii) an electrically non-conductive constituent, that when subjected to sufficient electrical energy, result in an exothermic reaction; and a flyer plate having a non-conductive surface in contact with said conductor. When the sufficient electrical energy is supplied to said conductor, rapid heating and vaporization of at least a portion of the conductor occurs so as to explosively drive at least a portion of the flyer plate away from said conductor. In an embodiment, a multilayer conductor may be formed of alternating layers of at least one electrically conductive layer, and at least one electrically non-conductive layer, that when subjected to sufficient electrical energy, result in an exothermic reaction.

Slip analysis of squeezing flow using doubly stratified fluid

NASA Astrophysics Data System (ADS)

Ahmad, S.; Farooq, M.; Javed, M.; Anjum, Aisha

2018-06-01

The non-isothermal flow is modeled and explored for squeezed fluid. The influence of velocity, thermal and solutal slip effects on transport features of squeezed fluid are analyzed through Darcy porous channel when fluid is moving due to squeezing of upper plate towards the stretchable lower plate. Dual stratification effects are illustrated in transport equations. A similarity analysis is performed and reduced governing flow equations are solved using moderated and an efficient convergent approach i.e. Homotopic technique. The significant effects of physical emerging parameters on flow velocity, temperature and fluid concentration are reporting through various plots. Graphical explanations for drag force, Nusselt and Sherwood numbers are stated and examined. The results reveal that minimum velocity field occurs near the plate, whereas it increases far away from the plate for strong velocity slip parameter. Furthermore, temperature and fluid concentration significantly decreases with increased slip effects. The current analysis is applicable in some advanced technological processes and industrial fluid mechanics.

Broadband high-efficiency half-wave plate: a supercell-based plasmonic metasurface approach.

PubMed

Ding, Fei; Wang, Zhuoxian; He, Sailing; Shalaev, Vladimir M; Kildishev, Alexander V

2015-04-28

We design, fabricate, and experimentally demonstrate an ultrathin, broadband half-wave plate in the near-infrared range using a plasmonic metasurface. The simulated results show that the linear polarization conversion efficiency is over 97% with over 90% reflectance across an 800 nm bandwidth. Moreover, simulated and experimental results indicate that such broadband and high-efficiency performance is also sustained over a wide range of incident angles. To further obtain a background-free half-wave plate, we arrange such a plate as a periodic array of integrated supercells made of several plasmonic antennas with high linear polarization conversion efficiency, consequently achieving a reflection-phase gradient for the cross-polarized beam. In this design, the anomalous (cross-polarized) and the normal (copolarized) reflected beams become spatially separated, hence enabling highly efficient and robust, background-free polarization conversion along with broadband operation. Our results provide strategies for creating compact, integrated, and high-performance plasmonic circuits and devices.

Performance of a circular cylinder piezoelectric wind energy harvester fitted with a splitter plate

NASA Astrophysics Data System (ADS)

Song, Jie; Hu, Gang; Tse, K. T.; Li, S. W.; Kwok, K. C. S.

2017-11-01

This study examines effects of the splitter plate placed in the near wake of a circular cylinder on the performance of a piezoelectric wind energy harvester through wind tunnel experiments. The kinetic energy of the harvester is gained by wind-induced vibrations of the circular cylinder. The splitter plate is attached to the leeward side of the cylinder. The ratio of the splitter plate length to the diameter of the circular cylinder (Lsp/D) ranges from 0.25 to 2.00. After attaching the splitter plate with an appropriate length, the harvester is able to sustain large amplitude vibrations beyond the wind speed range corresponding to vortex-induced vibrations. Thus, the upper bound of the wind speed range for the harvester to harness wind energy is eliminated, which significantly increases the efficiency of the harvester. Compared to the different lengths of the splitter plate, 0.65D has been found to be the optimal length for maximizing the harvested power.

Influence of nanofluids on the efficiency of Flat-Plate Solar Collectors (FPSC)

NASA Astrophysics Data System (ADS)

Nejad, Marjan B.; Mohammed, H. A.; Sadeghi, O.; Zubeer, Swar A.

2017-11-01

A numerical investigation is performed using finite volume method to study the laminar heat transfer in a three-dimensional flat-plate solar collector using different nanofluids as working fluids. Three nanofluids with different types of nanoparticles (Ag, MWCNT and Al2O3 dispersed in water) with 1-2 wt% volume fractions are analyzed. A constant heat flux, equivalent to solar radiation absorbed by the collector, is applied at the top surface of the absorber plate. In this study, several parameters including boundary conditions (different volume flow rates, different fluid inlet temperatures and different solar irradiance at Skudai, Malaysia), different types of nanoparticles, and different solar collector tilt angles are investigated to identify their effects on the heat transfer performance of FPSC. The numerical results reveal that the three types of nanofluid enhance the thermal performance of solar collector compared to pure water and FPSC with Ag nanofluid has the best thermal performance enhancement. For all the cases, the collector efficiency increased with the increase of volume flow rate while fluid outlet temperature decreased. It is found that FPSC with tilt angle of 10° and fluid inlet temperature of 301.15 K has the best thermal performance.

Mechanisms of Ionizing Radiation-Induced Cell Death in Primary Lung Cells

DTIC Science & Technology

2013-03-05

haemocytometer, and plated on 60 mm dishes coated with 0.5% gelatin (modification to allow attachment of PAEC). The cells were incubated for 14 days...we performed delayed plating where PAEC were first cultured to 70-90% confluence, exposed to varying doses of X-rays, incubated, and seeded then for...calculated as a function of plating efficiency of non-irradiated controls. The plating efficiency (PE) was defined as the percentage of the number

Absolute detection efficiencies of low energy H, H -, H +, H 2+ and H 3+ incident on a multichannel plate detector

NASA Astrophysics Data System (ADS)

Peko, B. L.; Stephen, T. M.

2000-12-01

Measured absolute detection efficiencies are presented for H, H - and H n+ ( n=1,2,3) impacting a commercially available, dual multichannel plate (MCP) electron multiplier at kinetic energies ranging from 30 to 1000 eV. Measurements involving isotopic substitutions (D, D -, D n+) and Ar + are also presented. In addition, atomic hydrogen detection efficiencies relative to those of H + and H - are given, as they may have a more universal application. For the three charge states, H, H + and H -, the absolute detection efficiencies are markedly different at low energies and converge to a nearly uniform value of ˜70% with increasing projectile energy. The energy dependence is strongest for H +, varying nearly three orders of magnitude over the energy range studied, and weakest for H -, varying by less than one order of magnitude. In general, for the low energy positive ions at a given energy, the lighter the incident particle mass, the greater the probability of its detection.

A method of vehicle license plate recognition based on PCANet and compressive sensing

NASA Astrophysics Data System (ADS)

Ye, Xianyi; Min, Feng

2018-03-01

The manual feature extraction of the traditional method for vehicle license plates has no good robustness to change in diversity. And the high feature dimension that is extracted with Principal Component Analysis Network (PCANet) leads to low classification efficiency. For solving these problems, a method of vehicle license plate recognition based on PCANet and compressive sensing is proposed. First, PCANet is used to extract the feature from the images of characters. And then, the sparse measurement matrix which is a very sparse matrix and consistent with Restricted Isometry Property (RIP) condition of the compressed sensing is used to reduce the dimensions of extracted features. Finally, the Support Vector Machine (SVM) is used to train and recognize the features whose dimension has been reduced. Experimental results demonstrate that the proposed method has better performance than Convolutional Neural Network (CNN) in the recognition and time. Compared with no compression sensing, the proposed method has lower feature dimension for the increase of efficiency.

The effect of automobile exhaust particulates on cell viability, plating efficiency and cell division of mammalian tissue culture cells.

PubMed

Seemayer, N H; Hadnagy, W; Tomingas, R

1987-03-01

Extract of particulate matter (EPM) of gasoline engine exhaust induced only a slight loss of cell viability of mouse macrophages (line IC-21) in vitro, while a strong dose-dependent reduction of plating efficiency of human cell line A-549 and of Syrian hamster line 14-1b occurred. Cytological investigations of exposed macrophages of line IC-21 revealed an increase in the mitotic index from 1.5% of control values up to 14.6% at the highest tested concentration of EPM. Mitotic arrest is based almost exclusively on C-type mitoses occurring dose-dependently in the presence of EPM. Results indicate disturbances of the spindle apparatus in the presence of EPM.

Roughness Effects on the Formation of a Leading Edge Vortex

NASA Astrophysics Data System (ADS)

Elliott, Cassidy; Lang, Amy; Wahidi, Redha; Wilroy, Jacob

2016-11-01

Microscopic scales cover the wings of Monarch butterflies, creating a patterned surface. This patterning is an important natural flow control mechanism that is thought to delay the growth of the leading edge vortex (LEV) produced by the flapping motion of a wing. The increased skin friction caused by the scales leads to a weaker LEV being shed into the butterfly's wake, lessening drag and increasing flight efficiency. To test this theory, a plate of random roughness was designed in SolidWorks and printed on the Objet 30 Pro 3D printer. A 2x3x5 cubic foot tow tank was used to test the rough plate at Reynold's numbers of 1500, 3000, and 6000 (velocities of 8, 16, and 32 mm/s) at an angle of attack of 45 degrees. Particle Image Velocimetry (PIV) captured images of the LEV generated by the plate when towed upwards through the particle-seeded flow. Codes written in MatLab were used to automatically track and determine the strength of the LEV. Circulation values for the randomly-rough plate were then compared to the same values generated in a previous experiment that used a smooth plate and a grooved plate to determine the effect of the patterning on vortex development. Funding provided by NSF REU site Grant EEC 1358991 and CBET 1628600.

Stress Distribution Around a Circular Hole in Square Plates, Loaded Uniformly in the Plane, on Two Opposite Sides of the Square. Optimum Shapes of Central Holes in Square Plates Subjected to Uniaxial Uniform Load. Optimization of Hole Shapes in Circular Cylindrical Shells Under Axial Tension,

DTIC Science & Technology

1981-09-01

brittle and photoelastic coatings, gages, grids, holography and speckle to solve two- and three-dimensional problems in elasticity, plasticity...weight by 10%. The efficiency coefficient is increased from 0.59 to 0.95. Tests with 4 brittle material show an increase in strength of 20%. An ideal...particularly useful for components made with brittle materials, or components made with ductile materials subjected to fatigue. Ple I Fa 441 ( .t

Absolute ion detection efficiencies of microchannel plates and funnel microchannel plates for multi-coincidence detection

NASA Astrophysics Data System (ADS)

Fehre, K.; Trojanowskaja, D.; Gatzke, J.; Kunitski, M.; Trinter, F.; Zeller, S.; Schmidt, L. Ph. H.; Stohner, J.; Berger, R.; Czasch, A.; Jagutzki, O.; Jahnke, T.; Dörner, R.; Schöffler, M. S.

2018-04-01

Modern momentum imaging techniques allow for the investigation of complex molecules in the gas phase by detection of several fragment ions in coincidence. For these studies, it is of great importance that the single-particle detection efficiency ɛ is as high as possible, as the overall efficiency scales with ɛn, i.e., the power of the number of detected particles. Here we present measured absolute detection efficiencies for protons of several micro-channel plates (MCPs), including efficiency enhanced "funnel MCPs." Furthermore, the relative detection efficiency for two-, three-, four-, and five-body fragmentation of CHBrClF has been examined. The "funnel" MCPs exhibit an efficiency of approximately 90%, gaining a factor of 24 (as compared to "normal" MCPs) in the case of a five-fold ion coincidence detection.

Scattering of turbulent-jet wavepackets by a swept trailing edge.

PubMed

Piantanida, Selene; Jaunet, Vincent; Huber, Jérôme; Wolf, William R; Jordan, Peter; Cavalieri, André V G

2016-12-01

Installed jet noise is studied by means of a simplified configuration comprising a flat plate in the vicinity of a round jet. The effects of Mach number, jet-plate radial distance, and trailing-edge sweep angle are explored. Acoustic measurements are performed using a traversable 18-microphone azimuthal array, providing pressure data at 360 points on a cylindrical surface surrounding the jet-plate system. Key observations include a decrease, with increasing Mach number, of the relative level of the scattered field in comparison to the uninstalled jet; an exponential dependence of the scattered sound pressure level on the radial jet-plate separation; and considerable sideline noise reductions with increasing sweep angle, with which there is an overall reduction in acoustic efficiency. The measurements are compared with results obtained using a kinematic wavepacket source model, whose radiation is computed in two ways. A TGF for a semi-infinite flat plate is used to provide a low-order approximation of the scattering effect. Use of a more computationally intensive boundary element method provides additional precision. Good agreement between model predictions and experiment, encouraging from the perspective of low-cost prediction strategies, demonstrates that the models comprise the essential sound generation mechanisms.

Apparatus and method for rapid cooling of large area substrates in vacuum

DOEpatents

Barth, Kurt L.; Enzenroth, Robert A.; Sampath, Walajabad S.

2012-11-06

The present invention is directed to an apparatus and method for rapid cooling of a large substrate in a vacuum environment. A first cooled plate is brought into close proximity with one surface of a flat substrate. The spatial volume between the first cooling plate and the substrate is sealed and brought to a higher pressure than the surrounding vacuum level to increase the cooling efficiency. A second cooled plate is brought into close proximity with the opposite surface of the flat substrate. A second spatial volume between the second cooling plate and the substrate is sealed and the gas pressure is equalized to the gas pressure in the first spatial volume. The equalization of the gas pressure on both sides of the flat substrate eliminates deflection of the substrate and bending stress in the substrate.

A comparative study of Cr-X-N (X=Zr, Si) coatings for the improvement of the low-speed torque efficiency of a hydraulic piston pump

NASA Astrophysics Data System (ADS)

Hong, Yeh-Sun; Lee, Sang-Yul

2008-02-01

The internal parts of hydraulic pumps operating at variable speed should be protected from insufficient lubrication. The axial piston type pumps employ a steel-base cylinder barrel rotating on a soft bronze valves plate with a slide contact, where the insufficient lubrication of these components can cause rapid wear of the valve plate and increase the friction loss. In this study, the cylinder barrel surface was deposited with CrZrN coatings, which were expected to improve the tribological contact with a valve plate under low-speed mixed lubrication conditions. Its effect on the improvement of the low-speed torque efficiency of a hydraulic piston pump was investigated and compared with that from the CrSiN coating. The coated cylinder barrels showed much lower friction coefficients and wear rates of the valve plates than the uncoated plasma-nitride one. In particular, the CrZrN coatings revealed better performance than the CrSiN coatings. By representing the improvement in the torque efficiency of the whole pump based upon the degree of the friction coefficient reduction, the CrZrN coatings exhibited approximately a 0.35% higher improvement at 300 bar and 100 rpm than CrSiN coatings. The possible failure modes of the coatings coated on the barrel were sugested and the microstructures of the coatings seemed to have a strong effect on the film failure mode.

Technology demonstration for reducing mercury emissions from small-scale gold refining facilities.

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

Habegger, L. J.; Fernandez, L. E.; Engle, M.

2008-06-30

Gold that is brought from artisanal and small-scale gold mining areas to gold shops for processing and sale typically contains 5-40% mercury. The uncontrolled removal of the residual mercury in gold shops by using high-temperature evaporation can be a significant source of mercury emissions in urban areas where the shops are located. Emissions from gold shop hoods during a burn can exceed 1,000 mg/m{sup 3}. Because the saturation concentration of mercury vapor at operating temperatures at the hood exhaust is less than 100 mg/m{sup 3}, the dominant component of the exhaust is in the form of aerosol or liquid particles.more » The U.S. Environmental Protection Agency (EPA), with technical support from Argonne National Laboratory (Argonne), has completed a project to design and test a technology to remove the dominant aerosol component in the emissions from gold shops. The objective was to demonstrate a technology that could be manufactured at low cost and by using locally available materials and manufacturing capabilities. Six prototypes designed by Argonne were locally manufactured, installed, and tested in gold shops in Itaituba and Creporizao, Brazil. The initial prototype design incorporated a pebble bed as the media for collecting the mercury aerosols, and a mercury collection efficiency of over 90% was demonstrated. Though achieving high efficiencies, the initial prototype was determined to have practical disadvantages such as excessive weight, a somewhat complex construction, and high costs (>US$1,000). To further simplify the construction, operation, and associated costs, a second prototype design was developed in which the pebble bed was replaced with slotted steel baffle plates. The system was designed to have flexibility for installation in various hood configurations. The second prototype with the baffle plate design was installed and tested in several different hood/exhaust systems to determine the optimal installation configuration. The significance of coagulation and collection of the mercury aerosols in exhaust ducts, which is dependent on the hood and collector configuration, was also evaluated. Prototype demonstration tests verified the theoretical basis for mercury aerosol capture that can be used to optimize the baffle plate design, flow rates, and hood exhaust ducts and plenum to achieve 80% or higher removal efficiencies. Results indicated that installation configuration significantly influences a system's capture efficiency. Configurations that retained existing inlet ducts resulted in system efficiencies of more than 80%, whereas installation configurations without inlet ducts significantly reduced capture efficiency. As an alternative to increasing the volume of inlet ducts, the number of baffle plates in the system baffle assembly could be doubled to increase efficiency. Recommended installation and operation procedures were developed on the basis of these results. A water-based mercury capture system developed in Indonesia for installation in smaller shops was also tested and shown to be effective for certain applications. The cost of construction and installation of the baffle plate prototype was approximately US$400. These costs were reported as acceptable by local gold shop owners and government regulators, and were significantly lower than the cost of an alternate charcoal/copper mesh mercury filter available in the region, which costs about US$10,000. A sampling procedure that consists of a particle filter combined with a vapor analyzer was demonstrated as an effective procedure for analyzing both the aerosol and vapor components of the mercury concentrations. Two key findings for enhancing higher mercury collection were identified. First, the aerosol/vapor mercury emissions must be given sufficient time for the mercury particles to coagulate to a size that can be readily captured by the baffle plates. An interval of at least 6 seconds of transit time between the point of evaporation and contact with the slotted baffle plates is recommended. Some particles will also deposit in the exhaust ducts between the point of evaporation and the baffle plates. Second, the slots in the baffle plates create jets that force the mercury particles to impinge and adhere on downstream surfaces. The baffle plates should closely follow the designs developed for this system to be most effective.« less

Magnetostrictive clad steel plates for high-performance vibration energy harvesting

NASA Astrophysics Data System (ADS)

Yang, Zhenjun; Nakajima, Kenya; Onodera, Ryuichi; Tayama, Tsuyoki; Chiba, Daiki; Narita, Fumio

2018-02-01

Energy harvesting technology is becoming increasingly important with the appearance of the Internet of things. In this study, a magnetostrictive clad steel plate for harvesting vibration energy was proposed. It comprises a cold-rolled FeCo alloy and cold-rolled steel joined together by thermal diffusion bonding. The performances of the magnetostrictive FeCo clad steel plate and conventional FeCo plate cantilevers were compared under bending vibration; the results indicated that the clad steel plate construct exhibits high voltage and power output compared to a single-plate construct. Finite element analysis of the cantilevers under bending provided insights into the magnetic features of a clad steel plate, which is crucial for its high performance. For comparison, the experimental results of a commercial piezoelectric bimorph cantilever were also reported. In addition, the cold-rolled FeCo and Ni alloys were joined by thermal diffusion bonding, which exhibited outstanding energy harvesting performance. The larger the plate volume, the more the energy generated. The results of this study indicated not only a promising application for the magnetostrictive FeCo clad steel plate as an efficient energy harvester, related to small vibrations, but also the notable feasibility for the formation of integrated units to support high-power trains, automobiles, and electric vehicles.

Sub-25-nm laboratory x-ray microscopy using a compound Fresnel zone plate.

PubMed

von Hofsten, Olov; Bertilson, Michael; Reinspach, Julia; Holmberg, Anders; Hertz, Hans M; Vogt, Ulrich

2009-09-01

Improving the resolution in x-ray microscopes is of high priority to enable future applications in nanoscience. However, high-resolution zone-plate optics often have low efficiency, which makes implementation in laboratory microscopes difficult. We present a laboratory x-ray microscope based on a compound zone plate. The compound zone plate utilizes multiple diffraction orders to achieve high resolution while maintaining reasonable efficiency. We analyze the illumination conditions necessary for this type of optics in order to suppress stray light and demonstrate microscopic imaging resolving 25 nm features.

Efficient needle plasma actuators for flow control and surface cooling

NASA Astrophysics Data System (ADS)

Zhao, Pengfei; Portugal, Sherlie; Roy, Subrata

2015-07-01

We introduce a milliwatt class needle actuator suitable for plasma channels, vortex generation, and surface cooling. Electrode configurations tested for a channel configuration show 1400% and 300% increase in energy conversion efficiency as compared to conventional surface and channel corona actuators, respectively, generating up to 3.4 m/s air jet across the channel outlet. The positive polarity of the needle is shown to have a beneficial effect on actuator efficiency. Needle-plate configuration is demonstrated for improving cooling of a flat surface with a 57% increase in convective heat transfer coefficient. Vortex generation by selective input signal manipulation is also demonstrated.

Impacts of Scheduling Recess before Lunch in Elementary Schools: A Case Study Approach of Plate Waste and Perceived Behaviors

ERIC Educational Resources Information Center

Strohbehn, Catherine H.; Strohbehn, Garth W.; Lanningham-Foster, Lorraine; Litchfield, Ruth A.; Scheidel, Carrie; Delger, Patti

2016-01-01

Purpose/Objectives: Recess Before Lunch (RBL) for elementary students is considered a best practice related to increased nutrient intakes at lunch, decreased afternoon behavioral issues, and increased afternoon learning efficiency; however, school characteristics, such as amount of time for lunch, offer vs. serve, and scheduling factors can…

Thermal Analysis of AlGaN/GaN High-Electron-Mobility Transistor and Its RF Power Efficiency Optimization with Source-Bridged Field-Plate Structure.

PubMed

Kwak, Hyeon-Tak; Chang, Seung-Bo; Jung, Hyun-Gu; Kim, Hyun-Seok

2018-09-01

In this study, we consider the relationship between the temperature in a two-dimensional electron gas (2-DEG) channel layer and the RF characteristics of an AlGaN/GaN high-electron-mobility transistor by changing the geometrical structure of the field-plate. The final goal is to achieve a high power efficiency by decreasing the channel layer temperature. First, simulations were performed to compare and contrast the experimental data of a conventional T-gate head structure. Then, a source-bridged field-plate (SBFP) structure was used to obtain the lower junction temperature in the 2-DEG channel layer. The peak electric field intensity was reduced, and a decrease in channel temperature resulted in an increase in electron mobility. Furthermore, the gate-to-source capacitance was increased by the SBFP structure. However, under the large current flow condition, the SBFP structure had a lower maximum temperature than the basic T-gate head structure, which improved the device electron mobility. Eventually, an optimum position of the SBFP was used, which led to higher frequency responses and improved the breakdown voltages. Hence, the optimized SBFP structure can be a promising candidate for high-power RF devices.

Hydrodynamics of a three-dimensional self-propelled flexible plate

NASA Astrophysics Data System (ADS)

Ryu, Jaeha; Sung, Hyung Jin

2017-11-01

A three-dimensional self-propelled flexible plate in a quiescent flow was simulated using the immersed boundary method. The clamped leading edge of the flexible plate was forced into a vertical oscillation, while free to move horizontally. To reveal the hydrodynamics of the plate, the averaged cruising speed (UC) , the input power (P) , and the swimming efficiency (η) were analyzed as a function of the bending rigidity (γ) and the flapping frequency (f) . The velocity field around the plate and the exerted force on the plate were demonstrated to find out the dynamic interaction between the plate and the surrounding fluid. The kinematics of the plate, the maximum angle of attack (ϕmax) , and the mean effective length (Leff) were examined accounting for the hydrodynamics of the self-propelled flexible plate. The vortical structures around the plate were visualized, and the influence of the tip vortex on the swimming efficiency was explored qualitatively and quantitatively. This work was supported by the Creative Research Initiatives (No. 2017-013369) program of the National Research Foundation of Korea (MSIP).

Comparison of traditional nondestructive analysis of RERTR fuel plates with digital radiographic techniques

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

Davidsmeier, T.; Koehl, R.; Lanham, R.

2008-07-15

The current design and fabrication process for RERTR fuel plates utilizes film radiography during the nondestructive testing and characterization. Digital radiographic methods offer a potential increases in efficiency and accuracy. The traditional and digital radiographic methods are described and demonstrated on a fuel plate constructed with and average of 51% by volume fuel using the dispersion method. Fuel loading data from each method is analyzed and compared to a third baseline method to assess accuracy. The new digital method is shown to be more accurate, save hours of work, and provide additional information not easily available in the traditional method.more » Additional possible improvements suggested by the new digital method are also raised. (author)« less

Shape and Stress Sensing of Multilayered Composite and Sandwich Structures Using an Inverse Finite Element Method

NASA Technical Reports Server (NTRS)

Cerracchio, Priscilla; Gherlone, Marco; Di Sciuva, Marco; Tessler, Alexander

2013-01-01

The marked increase in the use of composite and sandwich material systems in aerospace, civil, and marine structures leads to the need for integrated Structural Health Management systems. A key capability to enable such systems is the real-time reconstruction of structural deformations, stresses, and failure criteria that are inferred from in-situ, discrete-location strain measurements. This technology is commonly referred to as shape- and stress-sensing. Presented herein is a computationally efficient shape- and stress-sensing methodology that is ideally suited for applications to laminated composite and sandwich structures. The new approach employs the inverse Finite Element Method (iFEM) as a general framework and the Refined Zigzag Theory (RZT) as the underlying plate theory. A three-node inverse plate finite element is formulated. The element formulation enables robust and efficient modeling of plate structures instrumented with strain sensors that have arbitrary positions. The methodology leads to a set of linear algebraic equations that are solved efficiently for the unknown nodal displacements. These displacements are then used at the finite element level to compute full-field strains, stresses, and failure criteria that are in turn used to assess structural integrity. Numerical results for multilayered, highly heterogeneous laminates demonstrate the unique capability of this new formulation for shape- and stress-sensing.

Improvement of density resolution in short-pulse hard x-ray radiographic imaging using detector stacks

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

Borm, B.; Gärtner, F.; Khaghani, D.

2016-09-15

We demonstrate that stacking several imaging plates (IPs) constitutes an easy method to increase hard x-ray detection efficiency. Used to record x-ray radiographic images produced by an intense-laser driven hard x-ray backlighter source, the IP stacks resulted in a significant improvement of the radiograph density resolution. We attribute this to the higher quantum efficiency of the combined detectors, leading to a reduced photon noise. Electron-photon transport simulations of the interaction processes in the detector reproduce the observed contrast improvement. Increasing the detection efficiency to enhance radiographic imaging capabilities is equally effective as increasing the x-ray source yield, e.g., by amore » larger drive laser energy.« less

Removal of fly-ash and dust particulate matters from syngas produced by gasification of coal by using a multi-stage dual-flow sieve plate wet scrubber.

PubMed

Kurella, Swamy; Meikap, Bhim Charan

2016-08-23

In this work, fly-ash water scrubbing experiments were conducted in a three-stage lab-scale dual-flow sieve plate scrubber to observe the performance of scrubber in fly-ash removal at different operating conditions by varying the liquid rate, gas rate and inlet fly-ash loading. The percentage of fly-ash removal efficiency increases with increase in inlet fly-ash loading, gas flow rate and liquid flow rate, and height of the scrubber; 98.55% maximum percentage of fly-ash removal efficiency (ηFA) is achieved at 19.36 × 10(-4) Nm(3)/s gas flow rate (QG) and 48.183 × 10(-6) m(3)/s liquid flow rate (QL) at 25 × 10(-3) kg/Nm(3) inlet fly-ash loading (CFA,i). A model has also been developed for the prediction of fly-ash removal efficiency of the column using the experimental results. The predicted values calculated using the correlation matched well with the experimental results. Deviations observed between the experimental and the predicted values were less than 20%.

Efficient Sporulation of Saccharomyces cerevisiae in a 96 Multiwell Format.

PubMed

Paulissen, Scott M; Huang, Linda S

2016-09-17

During times of nutritional stress, Saccharomyces cerevisiae undergoes gametogenesis, known as sporulation. Diploid yeast cells that are starved for nitrogen and carbon will initiate the sporulation process. The process of sporulation includes meiosis followed by spore formation, where the haploid nuclei are packaged into environmentally resistant spores. We have developed methods for the efficient sporulation of budding yeast in 96 multiwell plates, to increase the throughput of screening yeast cells for sporulation phenotypes. These methods are compatible with screening with yeast containing plasmids requiring nutritional selection, when appropriate minimal media is used, or with screening yeast with genomic alterations, when a rich presporulation regimen is used. We find that for this method, aeration during sporulation is critical for spore formation, and have devised techniques to ensure sufficient aeration that are compatible with the 96 multiwell plate format. Although these methods do not achieve the typical ~80% level of sporulation that can be achieved in large-volume flask based experiments, these methods will reliably achieve about 50-60% level of sporulation in small-volume multiwell plates.

Anterior ankle arthrodesis

PubMed Central

Slater, Gordon L; Sayres, Stephanie C; O’Malley, Martin J

2014-01-01

Ankle arthrodesis is a common procedure that resolves many conditions of the foot and ankle; however, complications following this procedure are often reported and vary depending on the fixation technique. Various techniques have been described in the attempt to achieve ankle arthrodesis and there is much debate as to the efficiency of each one. This study aims to evaluate the efficiency of anterior plating in ankle arthrodesis using customised and Synthes TomoFix plates. We present the outcomes of 28 ankle arthrodeses between 2005 and 2012, specifically examining rate of union, patient-reported outcomes scores, and complications. All 28 patients achieved radiographic union at an average of 36 wk; the majority of patients (92.86%) at or before 16 wk, the exceptions being two patients with Charcot joints who were noted to have bony union at a three year review. Patient-reported outcomes scores significantly increased (P < 0.05). Complications included two delayed unions as previously mentioned, infection, and extended postoperative pain. With multiple points for fixation and coaxial screw entry points, the contoured customised plate offers added compression and provides a rigid fixation for arthrodesis stabilization. PMID:24649408

Stacked Fresnel Zone Plates for High Energy X-rays

NASA Astrophysics Data System (ADS)

Snigireva, Irina; Snigirev, Anatoly; Vaughan, Gavin; Di Michiel, Marco; Kohn, Viktor; Yunkin, Vyacheslav; Grigoriev, Maxim

2007-01-01

A stacking technique was developed in order to increase focusing efficiency of Fresnel zone plates (FZP) at high energies. Two identical Si chips each of which containing 9 FZPs were used for stacking. Alignment of the chips was achieved by on-line observation of the moiré pattern. The formation of moiré patterns was studied theoretically and experimentally at different experimental conditions. To provide the desired stability Si-chips were bonded together with slow solidification speed epoxy glue. A technique of angular alignment in order to compensate a linear displacement in the process of gluing was proposed. Two sets of stacked FZPs were experimentally tested to focus 15 and 50 keV x rays. The gain in the efficiency by factor 2.5 was demonstrated at 15 keV. The focal spot of 1.8 μm vertically and 14 μm horizontally with 35% efficiency was measured at 50 keV. Forecast for the stacking of nanofocusing FZPs was discussed.

Record Efficiency on Large Area P-Type Czochralski Silicon Substrates

NASA Astrophysics Data System (ADS)

Hallam, Brett; Wenham, Stuart; Lee, Haeseok; Lee, Eunjoo; Lee, Hyunwoo; Kim, Jisun; Shin, Jeongeun; Cho, Kyeongyeon; Kim, Jisoo

2012-10-01

In this work we report a world record independently confirmed efficiency of 19.4% for a large area p-type Czochralski grown solar cell fabricated with a full area aluminium back surface field. This is achieved using the laser doped selective emitter solar cell technology on an industrial screen print production line with the addition of laser doping and light induced plating equipment. The use of a modified diffusion process is explored in which the emitter is diffused to a sheet resistance of 90 Ω/square and subsequent etch back of the emitter to 120 Ω/square. This results in a lower surface concentration of phosphorus compared to that of emitters diffused directly to 120 Ω/square. This modified diffusion process subsequently reduces the conductivity of the surface in relation to that of the heavily diffused laser doped contacts and avoids parasitic plating, resulting an average absolute increase in efficiency of 0.4% compared to cells fabricated without an emitter etch back process.

Decolourization of Rhodamine B: A swirling jet-induced cavitation combined with NaOCl.

PubMed

Mancuso, Giuseppe; Langone, Michela; Laezza, Marco; Andreottola, Gianni

2016-09-01

A hydrodynamic cavitation reactor (Ecowirl) based on swirling jet-induced cavitation has been used in order to allow the degradation of a waste dye aqueous solution (Rhodamine B, RhB). Cavitation generated by Ecowirl reactor was directly compared with cavitation generated by using multiple hole orifice plates. The effects of operating conditions and parameters such as pressure, pH of dye solution, initial concentration of RhB and geometry of the cavitating devices on the degradation rate of RhB were discussed. In similar operative conditions, higher extents of degradation (ED) were obtained using Ecowirl reactor rather than orifice plate. An increase in the ED from 8.6% to 14.7% was observed moving from hole orifice plates to Ecowirl reactor. Intensification in ED of RhB by using hydrodynamic cavitation in presence of NaOCl as additive has been studied. It was found that the decolourization was most efficient for the combination of hydrodynamic cavitation and chemical oxidation as compared to chemical oxidation and hydrodynamic cavitation alone. The value of ED of 83.4% was reached in 37min using Ecowirl combined with NaOCl (4.0mgL(-1)) as compared to the 100min needed by only mixing NaOCl at the same concentration. At last, the energetic consumptions of the cavitation devices have been evaluated. Increasing the ED and reducing the treatment time, Ecowirl reactor resulted to be more energy efficient as compared to hole orifice plates, Venturi and other swirling jet-induced cavitation devices, as reported in literature. Copyright © 2016 Elsevier B.V. All rights reserved.

Phase III Advanced Anodes and Cathodes Utilized in Energy Efficient Aluminum Production Cells

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

R.A. Christini; R.K. Dawless; S.P. Ray

2001-11-05

During Phase I of the present program, Alcoa developed a commercial cell concept that has been estimated to save 30% of the energy required for aluminum smelting. Phase ii involved the construction of a pilot facility and operation of two pilots. Phase iii of the Advanced Anodes and Cathodes Program was aimed at bench experiments to permit the resolution of certain questions to be followed by three pilot cells. All of the milestones related to materials, in particular metal purity, were attained with distinct improvements over work in previous phases of the program. NiO additions to the ceramic phase andmore » Ag additions to the Cu metal phase of the cermet improved corrosion resistance sufficiently that the bench scale pencil anodes met the purity milestones. Some excellent metal purity results have been obtained with anodes of the following composition: Further improvements in anode material composition appear to be dependent on a better understanding of oxide solubilities in molten cryolite. For that reason, work was commissioned with an outside consultant to model the MeO - cryolite systems. That work has led to a better understanding of which oxides can be used to substitute into the NiO-Fe2O3 ceramic phase to stabilize the ferrites and reduce their solubility in molten cryolite. An extensive number of vertical plate bench electrolysis cells were run to try to find conditions where high current efficiencies could be attained. TiB2-G plates were very inconsistent and led to poor wetting and drainage. Pure TiB2 did produce good current efficiencies at small overlaps (shadowing) between the anodes and cathodes. This bench work with vertical plate anodes and cathodes reinforced the importance of good cathode wetting to attain high current efficiencies. Because of those conclusions, new wetting work was commissioned and became a major component of the research during the third year of Phase III. While significant progress was made in several areas, much work needs to be done. The anode composition needs further improvements to attain commercial purity targets. At the present corrosion rate, the vertical plate anodes will wear too rapidly leading to a rapidly increasing anode-cathode gap and thermal instabilities in the cell. Cathode wetting as a function of both cathode plate composition and bath composition needs to be better understood to ensure that complete drainage of the molten aluminum off the plates occurs. Metal buildup appears to lead to back reaction and low current efficiencies.« less

Sensor network based vehicle classification and license plate identification system

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

Frigo, Janette Rose; Brennan, Sean M; Rosten, Edward J

Typically, for energy efficiency and scalability purposes, sensor networks have been used in the context of environmental and traffic monitoring applications in which operations at the sensor level are not computationally intensive. But increasingly, sensor network applications require data and compute intensive sensors such video cameras and microphones. In this paper, we describe the design and implementation of two such systems: a vehicle classifier based on acoustic signals and a license plate identification system using a camera. The systems are implemented in an energy-efficient manner to the extent possible using commercially available hardware, the Mica motes and the Stargate platform.more » Our experience in designing these systems leads us to consider an alternate more flexible, modular, low-power mote architecture that uses a combination of FPGAs, specialized embedded processing units and sensor data acquisition systems.« less

Is Augmented LISS Plating Biomechanically Advantageous Over Conventional LISS Plating In Unstable Osteoporotic Distal Femoral Fractures?

PubMed

Todorov, Dimitar; Zderic, Ivan; Richards, R Geoff; Lenz, Mark; Knobe, Matthias; Enchev, Dian; Baltov, Asen; Gueorguiev, Boyko; Stoffel, Karl

2018-05-10

Treatment of complex osteoporotic distal femur fractures with the Less Invasive Stabilization System (LISS) has been associated with high complication rates. The aim of this study was to investigate the biomechanical competence of two different techniques of augmented versus conventional LISS plating. Unstable distal femoral fracture AO/OTA 33-A3 was created via osteotomies in artificial femora simulating osteoporotic bone. Three study groups, consisting of 10 specimens each, were created for instrumentation with either LISS plate, LISS plate with additional polylactide intramedullary graft, or LISS plate plus medial locking plate (double plating). All specimens were non-destructively tested under axial (20-150N) and torsional (0-4Nm) quasi-static loading. Each construct was tested with two different working length (WL) configurations (long and short) of the LISS plate. Relative movements between the most medial superior and inferior osteotomy aspects were investigated via three-dimensional motion tracking analysis. Double plating revealed significantly smaller longitudinal and shear displacement than the other two techniques (P≤0.001). In addition, LISS plus graft fixation was with significantly less longitudinal displacement in comparison to conventional LISS plating (P < 0.001). Long WL resulted in significantly higher longitudinal and shear displacement compared to short WL for LISS and LISS plus graft (P≤0.032), but not for double plating (P > 0.999). In conclusion, intramedullary grafting resulted in significantly increased fracture stability under axial loading in comparison to conventional LISS plating. Although it was not efficient enough to provide comparable stability to double plating, intramedullary grafting may be considered as a useful biological alternative to the latter in a surgeon's armamentarium. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

A new diagnostic method for separating airborne and structureborne noise radiated by plates with applications for propeller driven aircraft

NASA Technical Reports Server (NTRS)

Mcgary, Michael C.

1988-01-01

The anticipated application of advanced turboprop propulsion systems is expected to increase the interior noise of future aircraft to unacceptably high levels. The absence of technically and economically feasible noise source-path diagnostic tools has been a prime obstacle in the development of efficient noise control treatments for propeller-driven aircraft. A new diagnostic method that permits the separation and prediction of the fully coherent airborne and structureborne components of the sound radiated by plates or thin shells has been developed. Analytical and experimental studies of the proposed method were performed on an aluminum plate. The results of the study indicate that the proposed method could be used in flight, and has fewer encumbrances than the other diagnostic tools currently available.

Theoretical model of the helium zone plate microscope

NASA Astrophysics Data System (ADS)

Salvador Palau, Adrià; Bracco, Gianangelo; Holst, Bodil

2017-01-01

Neutral helium microscopy is a new technique currently under development. Its advantages are the low energy, charge neutrality, and inertness of the helium atoms, a potential large depth of field, and the fact that at thermal energies the helium atoms do not penetrate into any solid material. This opens the possibility, among others, for the creation of an instrument that can measure surface topology on the nanoscale, even on surfaces with high aspect ratios. One of the most promising designs for helium microscopy is the zone plate microscope. It consists of a supersonic expansion helium beam collimated by an aperture (skimmer) focused by a Fresnel zone plate onto a sample. The resolution is determined by the focal spot size, which depends on the size of the skimmer, the optics of the system, and the velocity spread of the beam through the chromatic aberrations of the zone plate. An important factor for the optics of the zone plate is the width of the outermost zone, corresponding to the smallest opening in the zone plate. The width of the outermost zone is fabrication limited to around 10 nm with present-day state-of-the-art technology. Due to the high ionization potential of neutral helium atoms, it is difficult to build efficient helium detectors. Therefore, it is crucial to optimize the microscope design to maximize the intensity for a given resolution and width of the outermost zone. Here we present an optimization model for the helium zone plate microscope. Assuming constant resolution and width of the outermost zone, we are able to reduce the problem to a two-variable problem (zone plate radius and object distance) and we show that for a given beam temperature and pressure, there is always a single intensity maximum. We compare our model with the highest-resolution zone plate focusing images published and show that the intensity can be increased seven times. Reducing the width of the outermost zone to 10 nm leads to an increase in intensity of more than 8000 times. Finally, we show that with present-day state-of-the-art detector technology (ionization efficiency 1 ×10-3 ), a resolution of the order of 10 nm is possible. In order to make this quantification, we have assumed a Lambertian reflecting surface and calculated the beam spot size that gives a signal 100 cts/s within a solid angle of 0.02 sr, following an existing helium microscope design.

Magnetic Fe-Co films electroplated in a deep-eutectic-solvent-based plating bath

NASA Astrophysics Data System (ADS)

Yanai, T.; Shiraishi, K.; Watanabe, Y.; Ohgai, T.; Nakano, M.; Suzuki, K.; Fukunaga, H.

2015-05-01

We fabricated Fe-Co films from a deep eutectic solvent (DES)-based plating bath and investigated magnetic properties of the plated films. The plating baths were obtained by stirring the mixture of choline chloride, ethylene glycol, FeCl2.4H2O, and CoCl2.6H2O. The composition of the plated films depended on the amount of FeCl2.4H2O in the plating bath, and Fe content of the films was varied from 0 to 100 at. %. Depending on the Fe content, the saturation magnetization and the coercivity of the films varied. The Fe76Co24 film shows high saturation magnetization and smooth surface, and the change in the saturation magnetization shows good agreement with the expected change by the Slater-Pauling curve. High current efficiency (>90%) could be obtained in the wide film composition. From these results, we concluded that the DES-based plating bath is one of effective baths for the Fe-Co films with high current efficiency.

Proceedings of the 2009 Antenna Applications Symposium, Volume 2

DTIC Science & Technology

2009-12-12

blowers and a heat pipe cold plate. Aspen systems is developing a high efficiency refrigeration based cooling system for cooling dish antenna systems...11.8 301.8 353.0 166.6 308 power amplifier, typically the major heat contributor. Increasing efficiency decreases heat required to be dissipated. This...The size of each array ballooned to a nominal 40 inches on a side and 11-13 inches high. The height was required by the air-air heat exchangers (the

Thermal Modeling of a Hybrid Thermoelectric Solar Collector with a Compound Parabolic Concentrator

NASA Astrophysics Data System (ADS)

Lertsatitthanakorn, C.; Jamradloedluk, J.; Rungsiyopas, M.

2013-07-01

In this study radiant light from the sun is used by a hybrid thermoelectric (TE) solar collector and a compound parabolic concentrator (CPC) to generate electricity and thermal energy. The hybrid TE solar collector system described in this report is composed of transparent glass, an air gap, an absorber plate, TE modules, a heat sink to cool the water, and a storage tank. Incident solar radiation falls on the CPC, which directs and reflects the radiation to heat up the absorber plate, creating a temperature difference across the TE modules. The water, which absorbs heat from the hot TE modules, flows through the heat sink to release its heat. The results show that the electrical power output and the conversion efficiency depend on the temperature difference between the hot and cold sides of the TE modules. A maximum power output of 1.03 W and a conversion efficiency of 0.6% were obtained when the temperature difference was 12°C. The thermal efficiency increased as the water flow rate increased. The maximum thermal efficiency achieved was 43.3%, corresponding to a water flow rate of 0.24 kg/s. These experimental results verify that using a TE solar collector with a CPC to produce both electrical power and thermal energy seems to be feasible. The thermal model and calculation method can be applied for performance prediction.

Ti/Al multilayer zone plate and Bragg-Fresnel lens.

PubMed

Koike, M; Suzuki, I H; Komiya, S; Amemiya, Y

1998-05-01

By using a helicon plasma sputtering technique, a one-dimensional Ti/Al multilayer zone plate with an outermost layer width of 76 nm has been successfully fabricated. A Bragg-Fresnel lens has been made by combining this zone plate with a Ge(422) crystal. Comparison of the Ti/Al multilayer zone plate with the Ag/Al zone plate is discussed in terms of focusing efficiency.

Ultrasonometry evaluation of axial compression osteosinthesis. An experimental study

PubMed Central

Bezuti, Márcio Takey; Mandarano, Luiz Garcia; Barbieri, Giuliano; Mazzer, Nilton; Barbieri, Cláudio Henrique

2013-01-01

OBJECTIVE: To measure the ultrasound propagation velocity (UV) through a tibial transverse osteotomy in sheep, before and after the fixation with a DCP plate. MATERIAL AND METHODS: Ten assemblies of a DCP plate with the diaphyseal segment of tibiae, in which a transverse osteotomy was made, were used. Both coronal and sagittal transverse and the axial UV were measured, first with the intact bone assembled with the plate and then with the uncompressed and compressed osteotomy; statistical comparisons were made at the 1% (p<0.01) level of significance. RESULTS: Compared with the intact bone assembly, axial UV significantly decreased with the addition of the osteotomy and significantly increased with compression, presenting the same behavior for the other modalities, although not significantly. DISCUSSION AND CONCLUSION: In accordance with the literature data on the ultrasonometric evaluation of fracture healing, underwater UV measurement was able to demonstrate the efficiency of DCP plate fixation. The authors conclude that the method has a potential for clinical application in the postoperative follow-up of DCP plate osteosinthesis, with a capability to demonstrate when it becomes ineffective. Laboratory investigation. PMID:24453644

Improving the performances of H-Darrieus cross-flow turbines through proper detached end plate designs

NASA Astrophysics Data System (ADS)

Villeneuve, Thierry; Boudreau, Matthieu; Dumas, Guy; CFD Laboratory LMFN Team

2017-11-01

Previous studies on H-Darrieus cross-flow turbines have highlighted the fact that their performances are highly sensitive to the detrimental effects associated with the blades tips. Wingtip devices could be designed in order to attenuate these effects, but the benefits of such devices are always impaired by their added viscous drag since they are moving with the turbine's blades. In this context, the development of fixed and detached end plates, i.e., which are not in contact with the turbine's blades, could reduce the tip losses without the undesirable added drag of typical wingtip devices moving with the blades. The case of a single stationary blade with detached end plates has first been investigated with RANS simulations in order to understand the mechanisms responsible for the increase of the blade's lift. An analysis of the vorticity lines' dynamics provides crucial insights into the effects of the gap width between the blade and the detached end plate on the blade's loading and on the intensity of the tip vortices. Based on these observations, various configurations of detached end plates are tested on cross-flow turbines via RANS and DDES simulations. Preliminary results show that appropriate detached end plates can significantly increase the turbines' efficiency. The authors gratefully acknowledge the Natural Sciences and Engineering Research Council of Canada (NSERC) for their financial support as well as Compute Canada and Calcul Québec for their supercomputer allocations.

Relative potentials of concentrating and two-axis tracking flat-plate photovoltaic arrays for central-station applications

NASA Technical Reports Server (NTRS)

Borden, C. S.; Schwartz, D. L.

1984-01-01

The purpose of this study is to assess the relative economic potentials of concenrating and two-axis tracking flat-plate photovoltaic arrays for central-station applications in the mid-1990's. Specific objectives of this study are to provide information on concentrator photovoltaic collector probabilistic price and efficiency levels to illustrate critical areas of R&D for concentrator cells and collectors, and to compare concentrator and flat-plate PV price and efficiency alternatives for several locations, based on their implied costs of energy. To deal with the uncertainties surrounding research and development activities in general, a probabilistic assessment of commercially achievable concentrator photovoltaic collector efficiencies and prices (at the factory loading dock) is performed. The results of this projection of concentrator photovoltaic technology are then compared with a previous flat-plate module price analysis (performed early in 1983). To focus this analysis on specific collector alternatives and their implied energy costs for different locations, similar two-axis tracking designs are assumed for both concentrator and flat-plate options.

Exact nonstationary responses of rectangular thin plate on Pasternak foundation excited by stochastic moving loads

NASA Astrophysics Data System (ADS)

Chen, Guohai; Meng, Zeng; Yang, Dixiong

2018-01-01

This paper develops an efficient method termed as PE-PIM to address the exact nonstationary responses of pavement structure, which is modeled as a rectangular thin plate resting on bi-parametric Pasternak elastic foundation subjected to stochastic moving loads with constant acceleration. Firstly, analytical power spectral density (PSD) functions of random responses for thin plate are derived by integrating pseudo excitation method (PEM) with Duhamel's integral. Based on PEM, the new equivalent von Mises stress (NEVMS) is proposed, whose PSD function contains all cross-PSD functions between stress components. Then, the PE-PIM that combines the PEM with precise integration method (PIM) is presented to achieve efficiently stochastic responses of the plate by replacing Duhamel's integral with the PIM. Moreover, the semi-analytical Monte Carlo simulation is employed to verify the computational results of the developed PE-PIM. Finally, numerical examples demonstrate the high accuracy and efficiency of PE-PIM for nonstationary random vibration analysis. The effects of velocity and acceleration of moving load, boundary conditions of the plate and foundation stiffness on the deflection and NEVMS responses are scrutinized.

Semi-automated high-efficiency reflectivity chamber for vacuum UV measurements

NASA Astrophysics Data System (ADS)

Wiley, James; Fleming, Brian; Renninger, Nicholas; Egan, Arika

2017-08-01

This paper presents the design and theory of operation for a semi-automated reflectivity chamber for ultraviolet optimized optics. A graphical user interface designed in LabVIEW controls the stages, interfaces with the detector system, takes semi-autonomous measurements, and monitors the system in case of error. Samples and an optical photodiode sit on an optics plate mounted to a rotation stage in the middle of the vacuum chamber. The optics plate rotates the samples and diode between an incident and reflected position to measure the absolute reflectivity of the samples at wavelengths limited by the monochromator operational bandpass of 70 nm to 550 nm. A collimating parabolic mirror on a fine steering tip-tilt motor enables beam steering for detector peak-ups. This chamber is designed to take measurements rapidly and with minimal oversight, increasing lab efficiency for high cadence and high accuracy vacuum UV reflectivity measurements.

A Compact Immunoassay Platform Based on a Multicapillary Glass Plate

PubMed Central

Xue, Shuhua; Zeng, Hulie; Yang, Jianmin; Nakajima, Hizuru; Uchiyama, Katsumi

2014-01-01

A highly sensitive, rapid immunoassay performed in the multi-channels of a micro-well array consisting of a multicapillary glass plate (MCP) and a polydimethylsiloxane (PDMS) slide is described. The micro-dimensions and large surface area of the MCP permitted the diffusion distance to be decreased and the reaction efficiency to be increased. To confirm the concept of the method, human immunoglobulin A (h-IgA) was measured using both the proposed immunoassay system and the traditional 96-well plate method. The proposed method resulted in a 1/5-fold decrease of immunoassay time, and a 1/56-fold cut in reagent consumption with a 0.05 ng/mL of limit of detection (LOD) for IgA. The method was also applied to saliva samples obtained from healthy volunteers. The results correlated well to those obtained by the 96-well plate method. The method has the potential for use in disease diagnostic or on-site immunoassays. PMID:24859022

Heat transfer and pressure drop characteristics of nanofluids in a plate heat exchanger.

PubMed

Kwon, Y H; Kim, D; Li, C G; Lee, J K; Hong, D S; Lee, J G; Lee, S H; Cho, Y H; Kim, S H

2011-07-01

In this paper, the heat transfer characteristics and pressure drop of the ZnO and Al2O3 nanofluids in a plate heat exchanger were studied. The experimental conditions were 100-500 Reynolds number and the respective volumetric flow rates. The working temperature of the heat exchanger was within 20-40 degrees C. The measured thermophysical properties, such as thermal conductivity and kinematic viscosity, were applied to the calculation of the convective heat transfer coefficient of the plate heat exchanger employing the ZnO and Al2O3 nanofluids made through a two-step method. According to the Reynolds number, the overall heat transfer coefficient for 6 vol% Al2O3 increased to 30% because at the given viscosity and density of the nanofluids, they did not have the same flow rates. At a given volumetric flow rate, however, the performance did not improve. After the nanofluids were placed in the plate heat exchanger, the experimental results pertaining to nanofluid efficiency seemed inauspicious.

Simultaneous removal of arsenite and fluoride via an integrated electro-oxidation and electrocoagulation process.

PubMed

Zhao, Xu; Zhang, Baofeng; Liu, Huijuan; Qu, Jiuhui

2011-04-01

An integrated electro-oxidation and electrocoagulation system was designed and used to remove As(III) and F(-) ions from water simultaneously. Dimensionally stable anodes (DSA), Fe electrodes, and Al electrodes were combined into an electrochemical system. Two pieces of DSA electrodes were assigned as the outside of the Fe and Al electrodes and were directly connected to the power supply as anode and cathode, respectively. The Fe and Al ions were generated by electro-induced process simultaneously. Subsequently, hydroxides of Fe and Al were formed. Arsenic ions are mainly removed by iron hydroxides and F(-) ions are mainly removed by the Al oxides. At the initial concentration of 1.0 mg L(-1), most of As(III) was transferred into As(V) within 40 min at current density of 4 mA cm(-2), whereas F(-) ions can be efficiently removed simultaneously. The effect of the ratio of Fe and Al plate electrodes and current density on the removal of As(III) and F(-) was investigated. With one piece of Fe plate electrode and three pieces of Al plate electrodes, it is observed that As(III) with concentration of 1 mg L(-1) and F(-) with concentration of 4.5 mg L(-1) can be removed and their final concentrations were below the values of 10 μg L(-1) and 1.0 mg L(-1), respectively within 40 min. Removal efficiency of As(III) increases with the increase of solution pH. However, in the pH range of 6-7, removal efficiency of F(-) is the largest. Copyright © 2011 Elsevier Ltd. All rights reserved.

EFFECTS OF TURBULENCE AND ELECTROHYDRODYAMICS ON THE PERFORMANCE OF ELECTROSTATIC PRECIPITATORS

EPA Science Inventory

Numerical simulations of the turbulent diffusion equation coupled with the electrohydrodynamics (EHD) are carried out for the plate-plate and wire-plate ESPs. The local particle concentration profiles and fractional collection efficiencies have been evaluated as a function of thr...

Utilizing Diffuse Reflection to Increase the Efficiency of Luminescent Solar Concentrators

NASA Astrophysics Data System (ADS)

Bowser, Seth; Weible, Seth; Solomon, Joel; Schrecengost, Jonathan; Wittmershaus, Bruce

A luminescent solar concentrator (LSC) consists of a high index solid plate containing a fluorescent material that converts sunlight into fluorescence. Utilizing total internal reflection, the LSC collects and concentrates the fluorescence at the plate's edges where it is converted into electricity via photovoltaic solar cells. The lower production costs of LSCs make them an attractive alternative to photovoltaic solar cells. To optimize an LSC's efficiency, a white diffusive surface (background) is positioned behind it. The background allows sunlight transmitted in the first pass to be reflected back through the LSC providing a second chance for absorption. Our research examines how the LSC's performance is affected by changing the distance between the white background and the LSC. An automated linear motion apparatus was engineered to precisely measure this distance and the LSC's electrical current, simultaneously. LSC plates, with and without the presence of fluorescent material and in an isolated environment, showed a maximum current at a distance greater than zero. Further experimentation has proved that the optimal distance results from the background's optical properties and how the reflected light enters the LSC. This material is based upon work supported by the National Science Foundation under Grant Number NSF-ECCS-1306157.

Effectiveness of fins formed by dimples in the form of ball segments

NASA Astrophysics Data System (ADS)

Gabdrakhmanov, E. A.; Afonin, G. N.; Glazov, V. S.

2017-11-01

One of the famous ways to improve efficiency of a heat exchanger is associated with the topography of the surfaces being in contact with coolants. So, use of hemispherical dimples leads to progressive growth of the relative heat transfer coefficient compared to increase of the relative resistance coefficient. Usually a plate having the spherical dimple intensifiers for heat transfer is considered as a flat one with embedded cavities. However, such a plate can be also considered as the plate with inbuilt fins which are formed by dimples in the form of ball segments. Given that for the flow of fluid (gas) from left to right, the minimum local heat transfer enhancement occurs in the first (left) half of the dimples, and the maximum falls on the edge of the second (right) half, we obtained an analytical solution describing the temperature distribution along the height of the fin. In the solution we used the Harper-Brown approach. Presented are the results of the calculation of the efficiency of the surface on the parameters of the considered fin and on a known value of the average heat transfer coefficient corresponding to the stage of the fluid flow steady state.

Free-Standing Zone Plate Optimized for He II 30.4 nm Solar Irradiance Measurements Having High Accuracy and Stability in Space

NASA Astrophysics Data System (ADS)

Seely, J. F.; McMullin, D. R.; Vest, R.; Sakdinawat, A.; Chang, C.; Jones, A. R.; Bremer, J.

2015-12-01

A zone plate was designed to record the He II 30.4 nm solar irradiance, was fabricated using electron beam lithography, and was absolutely calibrated using the NIST SURF synchrotron. The zone plate has an open support grid identical to those used to successfully launch transmission gratings in previous solar radiometers and is otherwise free-standing with no support membrane that would absorb EUV radiation. The measured efficiency of 3.0 ± 0.1% at 30.4 nm is consistent with detailed modeling of the efficiency and accounting for the geometrical transmittance of the support grid. The binary nature of the zone plate, consisting of opaque gold bars and open spaces with no support membrane, results in excellent long-term stability in space against contamination, radiation damage, and other effects that could alter the efficiency and instrument throughput. The zone plate's focusing property enables the rejection of out-of-band radiation by small apertures and high signal to background values that are superior to previous radiometers. The 4 mm outer diameter of the zone plate and the 25 mm focal length for 30.4 nm radiation enable a compact instrument that is attractive for small CubeSats and other space flight missions where resources are extremely limited.

Flat plate vs. concentrator solar photovoltaic cells - A manufacturing cost analysis

NASA Technical Reports Server (NTRS)

Granon, L. A.; Coleman, M. G.

1980-01-01

The choice of which photovoltaic system (flat plate or concentrator) to use for utilizing solar cells to generate electricity depends mainly on the cost. A detailed, comparative manufacturing cost analysis of the two types of systems is presented. Several common assumptions, i.e., cell thickness, interest rate, power rate, factory production life, polysilicon cost, and direct labor rate are utilized in this analysis. Process sequences, cost variables, and sensitivity analyses have been studied, and results of the latter show that the most important parameters which determine manufacturing costs are concentration ratio, manufacturing volume, and cell efficiency. The total cost per watt of the flat plate solar cell is $1.45, and that of the concentrator solar cell is $1.85, the higher cost being due to the increased process complexity and material costs.

Calibration of a microchannel plate based extreme ultraviolet grazing incident spectrometer at the Advanced Light Source

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

Bakeman, M. S.; Lawrence Berkeley National Laboratory, Berkeley, California 94720; Tilborg, J. van

We present the design and calibration of a microchannel plate based extreme ultraviolet spectrometer. Calibration was performed at the Advance Light Source (ALS) at the Lawrence Berkeley National Laboratory (LBNL). This spectrometer will be used to record the single shot spectrum of radiation emitted by the tapered hybrid undulator (THUNDER) undulator installed at the LOASIS GeV-class laser-plasma-accelerator. The spectrometer uses an aberration-corrected concave grating with 1200 lines/mm covering 11-62 nm and a microchannel plate detector with a CsI coated photocathode for increased quantum efficiency in the extreme ultraviolet. A touch screen interface controls the grating angle, aperture size, and placementmore » of the detector in vacuum, allowing for high-resolution measurements over the entire spectral range.« less

Porous and Microporous Honeycomb Composites as Potential Boundary-Layer Bleed Materials

NASA Technical Reports Server (NTRS)

Davis, D. O.; Willis, B. P.; Schoenenberger, M.

1997-01-01

Results of an experimental investigation are presented in which the use of porous and microporous honeycomb composite materials is evaluated as an alternate to perforated solid plates for boundary-layer bleed in supersonic aircraft inlets. The terms "porous" and "microporous," respectively, refer to bleed orifice diameters roughly equal to and much less than the displacement thickness of the approach boundary-layer. A Baseline porous solid plate, two porous honeycomb, and three microporous honeycomb configurations are evaluated. The performance of the plates is characterized by the flow coefficient and relative change in boundary-layer profile parameters across the bleed region. The tests were conducted at Mach numbers of 1.27 and 1.98. The results show the porous honeycomb is not as efficient at removing mass compared to the baseline. The microporous plates were about equal to the baseline with one plate demonstrating a significantly higher efficiency. The microporous plates produced significantly fuller boundary-layer profiles downstream of the bleed region for a given mass flow removal rate than either the baseline or the porous honeycomb plates.

Development of Electrospun Nanomaterials and their Applications in Separation Science

NASA Astrophysics Data System (ADS)

Newsome, Toni Elwell

In separations, efficiency is inversely related to the diameter of the sorbent particles of the stationary phase. Thus, materials research in separation science has primarily been directed towards reducing the diameter of the sorbent particle used in the stationary phase. In this dissertation, innovative methods designed for the fabrication and application of electrospun sorbent nanomaterials for separation science are described. Electrospinning is a facile, cost-effective technique that relies on repulsive electrostatic forces to produce nanofibers from a viscoelastic solution. Here, electrospinning is used to generate polymer, carbon, and silica-based nanofibers which are employed as sorbent nanomaterials in extractions and separations. Electrospun carbon nanofibers have proven to be ideal extractive phases for solid-phase microextraction (SPME) when coupled to gas chromatography (GC) for headspace sampling of volatile analytes. Herein, these carbon nanofibers were employed in the direct extraction of nonvolatile analytes and coupled to liquid chromatography (LC) for the first time. The high surface area of the coatings led to enhanced extraction efficiencies; they offered a 3-33 fold increase in efficiency relative to a commercial SPME phase. Carbon nanofibers proved to be stable when immersed in liquids common to LC demonstrating the enhanced stability of these coatings in SPME coupled to LC relative to conventional SPME fibers. The enhanced chemical and mechanical stability of the carbon SPME coatings considerably expanded the range of compounds applicable to SPME and extended the lifetimes of the fibers. Electrospun nanofibers have also proven to be ideal stationary phases in ultra-thin layer chromatography (UTLC). Nanofibers provide faster separations and enhanced separation efficiencies compared to commercial particle-based stationary phases in a relatively short distance. Here, the electrospun-UTLC technology was extended for the first time to nanofibers composed of silica, the most commonly used surface for TLC. An electrospinning method was optimized to produce silica-based nanofibers with the smallest diameter possible (300-380 nm) while maintaining homogenous nanofiber morphology. Highly efficient separations were performed in 15 mm with observed plate heights as low as 8.6 mum. Silica-based nanofibers proved to be chemically stable with a wide variety of TLC reagents demonstrating the enhanced compatibility of these phases with common TLC methods relative to polymer and carbon nanofiber UTLC plates. The extension of electrospun UTLC to silica-based nanofibers vastly expanded the range of analytes and TLC methods which can be used with this technology. The main disadvantage of conventional TLC development methods is that the mobile phase velocity decreases with increasing separation distance. Here, the chromatographic performance of electrospun polymer stationary phases was further improved by using a forced-flow mobile phase in planar electrochromatography (PEC) in which mobile phase velocity does not diminish with increasing distance. Separations were performed on polymer nanofiber UTLC plates in 1-2 min. Compared to UTLC, PEC offered unique selectivity, decreased analysis times (> 4 times faster), and enhanced efficiency (2-3 times lower plate height). In addition, two-dimensional (2D) separations of a complex analyte mixture using UTLC followed by PEC required only 11 min and exhibited a significant increase in separation number (70-77).

Performance Analysis of a Thermoelectric Solar Collector Integrated with a Heat Pump

NASA Astrophysics Data System (ADS)

Lertsatitthanakorn, C.; Jamradloedluk, J.; Rungsiyopas, M.; Therdyothin, A.; Soponronnarit, S.

2013-07-01

A novel heat pump system is proposed. A thermoelectric solar collector was coupled to a solar-assisted heat pump (TESC-HP) to work as an evaporator. The cooling effect of the system's refrigerant allowed the cold side of the system's thermoelectric modules to work at lower temperature, improving the conversion efficiency. The TESC-HP system mainly consisted of transparent glass, an air gap, an absorber plate that acted as a direct expansion-type collector/evaporator, an R-134a piston-type hermetic compressor, a water-cooled plate-type condenser, thermoelectric modules, and a water storage tank. Test results indicated that the TESC-HP has better coefficient of performance (COP) and conversion efficiency than the separate units. For the meteorological conditions in Mahasarakham, the COP of the TESC-HP system can reach 5.48 when the average temperature of 100 L of water is increased from 28°C to 40°C in 60 min with average ambient temperature of 32.5°C and average solar intensity of 815 W/m2, whereas the conversion efficiency of the TE power generator was around 2.03%.

High-Dose Neutron Detector Development Using 10B Coated Cells

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

Menlove, Howard Olsen; Henzlova, Daniela

2016-11-08

During FY16 the boron-lined parallel-plate technology was optimized to fully benefit from its fast timing characteristics in order to enhance its high count rate capability. To facilitate high count rate capability, a novel fast amplifier with timing and operating properties matched to the detector characteristics was developed and implemented in the 8” boron plate detector that was purchased from PDT. Each of the 6 sealed-cells was connected to a fast amplifier with corresponding List mode readout from each amplifier. The FY16 work focused on improvements in the boron-10 coating materials and procedures at PDT to significantly improve the neutron detectionmore » efficiency. An improvement in the efficiency of a factor of 1.5 was achieved without increasing the metal backing area for the boron coating. This improvement has allowed us to operate the detector in gamma-ray backgrounds that are four orders of magnitude higher than was previously possible while maintaining a relatively high counting efficiency for neutrons. This improvement in the gamma-ray rejection is a key factor in the development of the high dose neutron detector.« less

Promoting protein crystallization using a plate with simple geometry.

PubMed

Chen, Rui-Qing; Yin, Da-Chuan; Liu, Yong-Ming; Lu, Qin-Qin; He, Jin; Liu, Yue

2014-03-01

Increasing the probability of obtaining protein crystals in crystallization screening is always an important goal for protein crystallography. In this paper, a new method called the cross-diffusion microbatch (CDM) method is presented, which aims to efficiently promote protein crystallization and increase the chance of obtaining protein crystals. In this method, a very simple crystallization plate was designed in which all crystallization droplets are in one sealed space, so that a variety of volatile components from one droplet can diffuse into any other droplet via vapour diffusion. Crystallization screening and reproducibility tests indicate that this method could be a potentially powerful technique in practical protein crystallization screening. It can help to obtain crystals with higher probability and at a lower cost, while using a simple and easy procedure.

Plate refractive camera model and its applications

NASA Astrophysics Data System (ADS)

Huang, Longxiang; Zhao, Xu; Cai, Shen; Liu, Yuncai

2017-03-01

In real applications, a pinhole camera capturing objects through a planar parallel transparent plate is frequently employed. Due to the refractive effects of the plate, such an imaging system does not comply with the conventional pinhole camera model. Although the system is ubiquitous, it has not been thoroughly studied. This paper aims at presenting a simple virtual camera model, called a plate refractive camera model, which has a form similar to a pinhole camera model and can efficiently model refractions through a plate. The key idea is to employ a pixel-wise viewpoint concept to encode the refraction effects into a pixel-wise pinhole camera model. The proposed camera model realizes an efficient forward projection computation method and has some advantages in applications. First, the model can help to compute the caustic surface to represent the changes of the camera viewpoints. Second, the model has strengths in analyzing and rectifying the image caustic distortion caused by the plate refraction effects. Third, the model can be used to calibrate the camera's intrinsic parameters without removing the plate. Last but not least, the model contributes to putting forward the plate refractive triangulation methods in order to solve the plate refractive triangulation problem easily in multiviews. We verify our theory in both synthetic and real experiments.

Three Dimensional Forming Simulation of the Shielded Slot Plate for the MCFC Using a Ductile Fracture Criterion

NASA Astrophysics Data System (ADS)

Lee, C. H.; Yang, D. Y.; Lee, S. R.; Chang, I. G.; Lee, T. W.

2011-08-01

The shielded slot plate, which has a sheared corrugated trapezoidal pattern, is a component of the metallic bipolar plate for the molten carbonate fuel cell (MCFC). In order to increase the efficiency of the fuel cell, the unit cell of the shielded slot plate should have a relatively large upper area. Additionally, defects from the forming process should be minimized. In order to simulate the slitting process, whereby sheared corrugated patterns are formed, ductile fracture criteria based on the histories of stress and strain are employed. The user material subroutine VUMAT is employed for implementation of the material and ductile fracture criteria in the commercial FEM software ABAQUS. The variables of the ductile fracture criteria were determined by comparing the simulation results and the experimental results of the tension test and the shearing test. Parametric studies were conducted to determine the critical value of the ductile fracture criterion. Employing these ductile fracture criteria, the three dimensional forming process of the shielded slot plate was numerically simulated. The effects of the slitting process in the forming process of the shielded slot plate were analyzed through a FEM simulation and experimental studies. Finally, experiments involving microscopic and macroscopic observations were conducted to verify the numerical simulations of the 3-step forming process.

Roughness Effects on the Formation of a Leading Edge Vortex

NASA Astrophysics Data System (ADS)

Elliott, Cassidy; Lang, Amy; Wahidi, Redha; Wilroy, Jacob

2017-11-01

Microscopic scales cover the wings of Monarch butterflies, creating a patterned surface that acts as a natural energy capture mechanism. This patterning is thought to delay the growth of the leading edge vortex (LEV) produced by the flapping motion of a wing. Increased skin friction caused by the scales leads to a weaker LEV being shed into the butterfly's wake, lessening drag and increasing flight efficiency. To test how this roughness effects LEV formation, a plate of random roughness was designed in SolidWorks and printed on the Objet 30 Pro 3D printer. A 2x3x5 cubic foot tow tank was used to test the rough plate at Reynold's numbers of 1500, 3000, and 6000 (velocities of 8, 16, and 32 mm/s) at an angle of attack of 45 degrees. Images were captured of the LEV generated when the plate was towed upwards through the particle-seeded flow. These images were used to determine the XY velocity of the particles using a technique called Digital Particle Image Velocimetry (DPIV). Codes written in MATLAB were used to track and measure the strength of the LEV. Circulation values for the randomly-rough plate were then compared to the same values generated in a previous experiment that used a smooth plate and a grooved plate to determine the effect of the patterning on vortex development. Funding for this research project was provided by the National Science Foundation under the Research Experience for Undergraduates (REU) program (REU Supplement CBET 1628600 under CBET 1335848).

Plate-shaped Yb:LuPO4 crystal for efficient CW and passively Q-switched microchip lasers

NASA Astrophysics Data System (ADS)

Liu, Junhai; Wang, Lisha; Han, Wenjuan; Xu, Honghao; Zhong, Degao; Teng, Bing

2016-10-01

It is demonstrated that plate-shaped crystals of Yb:LuPO4, which are grown from spontaneous nucleation by high-temperature solution method, can be utilized to make microchip lasers operating in continuous-wave (CW) or passively Q-switched mode. Efficient operation of such a microchip laser, which is built with a 0.3 mm thick crystal plate in a 2 mm long plane-parallel cavity, is realized at room temperature. With 2.37 W of pump power absorbed, 1.45 W of CW output power is generated with a slope efficiency of 73%. When passively Q-switched with a Cr4+:YAG crystal plate as saturable absorber, the laser produces a maximum pulsed output power of 0.53 W at 1013.3 nm, at a pulse repetition rate of 23.8 kHz, the resulting pulse energy, duration, and peak power are 22.3 μJ, 4.0 ns, and 5.6 kW, respectively.

Absolute and angular efficiencies of a microchannel-plate position-sensitive detector

NASA Technical Reports Server (NTRS)

Gao, R. S.; Gibner, P. S.; Newman, J. H.; Smith, K. A.; Stebbings, R. F.

1984-01-01

This paper presents a characterization of a commercially available position-sensitive detector of energetic ions and neutrals. The detector consists of two microchannel plates followed by a resistive position-encoding anode. The work includes measurement of absolute efficiencies of H(+), He(+), and O(+) ions in the energy range between 250 and 5000 eV, measurement of relative detection efficiencies as a function of particle impact angle, and a simple method for accurate measurement of the time at which a particle strikes the detector.

The quantitative impact of the mesopore size on the mass transfer mechanism of the new 1.9μm fully porous Titan-C18 particles. I: analysis of small molecules.

PubMed

Gritti, Fabrice; Guiochon, Georges

2015-03-06

Previous data have shown that could deliver a minimum reduced plate height as small as 1.7. Additionally, the reduction of the mesopore size after C18 derivatization and the subsequent restriction for sample diffusivity across the Titan-C18 particles were found responsible for the unusually small value of the experimental optimum reduced velocity (5 versus 10 for conventional particles) and for the large values of the average reduced solid-liquid mass transfer resistance coefficients (0.032 versus 0.016) measured for a series of seven n-alkanophenones. The improvements in column efficiency made by increasing the average mesopore size of the Titan silica from 80 to 120Å are investigated from a quantitative viewpoint based on the accurate measurements of the reduced coefficients (longitudinal diffusion, trans-particle mass transfer resistance, and eddy diffusion) and of the intra-particle diffusivity, pore, and surface diffusion for the same series of n-alkanophenone compounds. The experimental results reveal an increase (from 0% to 30%) of the longitudinal diffusion coefficients for the same sample concentration distribution (from 0.25 to 4) between the particle volume and the external volume of the column, a 40% increase of the intra-particle diffusivity for the same sample distribution (from 1 to 7) between the particle skeleton volume and the bulk phase, and a 15-30% decrease of the solid-liquid mass transfer coefficient for the n-alkanophenone compounds. Pore and surface diffusion are increased by 60% and 20%, respectively. The eddy dispersion term and the maximum column efficiency (295000plates/m) remain virtually unchanged. The rate of increase of the total plate height with increasing the chromatographic speed is reduced by 20% and it is mostly controlled (75% and 70% for 80 and 120Å pore size) by the flow rate dependence of the eddy dispersion term. Copyright © 2015 Elsevier B.V. All rights reserved.

Color and shape discrimination in the stingless bee Scaptotrigona mexicana Guérin (Hymenoptera, Apidae).

PubMed

Sánchez, D; Vandame, R

2012-06-01

To increase our understanding in bee vision ecology, we investigated the color and shape discrimination performance of the stingless bee Scaptotrigona mexicana Guérin. Our main goal was to describe the choice behavior of experienced foragers over time, trying to understand to what extent color and shape stimuli (separately tested) aid them to choose the rewarding option, in the presence of distracting, unrewarding stimuli. Single foragers were trained to collect sucrose solution from a target plate. Afterwards, one distracting, unrewarding plate was placed besides the target plate and eight choices were recorded. Our results showed that both color and shape stimuli assisted efficiently the trained foragers in locating the target plate. However, foragers chose significantly more often the target plate in the color experiments than in the shape experiments. In conclusion, in our experimental setup, color was of better assistance to the foragers of S. mexicana than shape to choose their rewards. This is the first study in which it is demonstrated that the choice performance over time in a stingless bee depends upon the characteristics of the resource, such as shape and color.

Development of an economic solar heating system with cost efficient flat plate collectors

NASA Astrophysics Data System (ADS)

Eder-Milchgeisser, W.; Burkart, R.

1980-10-01

Mass produced flat plate solar collectors were worked into the design of a system for heating a swimming pool and/or providing domestic hot water. The collector characteristics, including physical and mechanical data as well as theoretical energy conversion efficiency, are presented. The collector was tested and service life efficiency was determined. The mounting of the collector, depending on roof type, is explained. Both in service and laboratory test results demonstrate the cost effectiveness of the system. Further improvement of efficiency is envisaged with automatic flow control in the solar collector and hot water circuits.

Post-mitotic human dermal fibroblasts efficiently support the growth of human follicular keratinocytes.

PubMed

Limat, A; Hunziker, T; Boillat, C; Bayreuther, K; Noser, F

1989-05-01

For growth at low seeding densities, keratinocytes isolated from human tissues like epidermis or hair follicles are dependent on mesenchyme-derived feeder cells such as the 3T3-cell employed so far. As an alternative method, the present study describes the use of post-mitotic human dermal fibroblasts sublethally irradiated or mitomycin C-treated. Special emphasis was put on efficient growth of primary keratinocyte cultures plated at very low seeding densities. Thus, outer root sheath cells isolated from two anagen human hair follicles and plated in a 35-mm culture dish (3 - 6 X 10(2) attached cells) grew to confluence within 3 weeks (6 - 8 X 10(5) cells). Similar results were obtained for interfollicular keratinocytes. A crucial point for the function of these fibroblast feeder cells is plating at appropriate densities, considering their tremendous increase in cell size at the post-mitotic state. Plating densities of 4 - 5 X 10(3/cm2 allow full spreading of the feeder cells and do not impede the settling and expansion of the keratinocytes. Major advantages of this system include easier handling and better reproducibility than using 3T3-cells. Moreover, homologous fibroblast feeders mimic more closely the physiologic situation and therefore might provide a valuable tool for studying interactions between human mesenchymal and epithelial cells. Finally, potential hazards of using transformed feeder cells from a different species in keratinocyte cultures raised for wound covering in humans could be thus avoided.

Enhancing performance and uniformity of CH3NH3PbI3-xClx perovskite solar cells by air-heated-oven assisted annealing under various humidities

NASA Astrophysics Data System (ADS)

Zhou, Qing; Jin, Zhiwen; Li, Hui; Wang, Jizheng

2016-02-01

To fabricate high-performance metal-halide perovskite solar cells, a thermal annealing process is indispensable in preparing high quality perovskite film. And usually such annealing is performed on hot plate. However hot-plate annealing could cause problems such as inhomogeneous heating (induced by non-tight contact between the sample and the plate), it is also not fit for large scale manufactory. In this paper, we conduct the annealing process in air-heated oven under various humidity environments, and compared the resulted films (CH3NH3PbI3-xClx) and devices (Al/PC61BM/CH3NH3PbI3-xClx/PEDOT:PSS/ITO/glass) with that obtained via hot-plate annealing. It is found that the air-heated-oven annealing is superior to the hot-plate annealing: the annealing time is shorter, the films are more uniform, and the devices exhibit higher power conversion efficiency and better uniformity. The highest efficiencies achieved for the oven and hot-plate annealing processes are 14.9% and 13.5%, and the corresponding standard deviations are 0.5% and 0.8%, respectively. Our work here indicates that air-heated-oven annealing could be a more reliable and more efficient way for both lab research and large-scale production.

Fabrication and characterization of high-efficiency double-sided blazed x-ray optics.

PubMed

Mohacsi, Istvan; Vartiainen, Ismo; Guizar-Sicairos, Manuel; Karvinen, Petri; Guzenko, Vitaliy A; Müller, Elisabeth; Kewish, Cameron M; Somogyi, Andrea; David, Christian

2016-01-15

The focusing efficiency of conventional diffractive x-ray lenses is fundamentally limited due to their symmetric binary structures and the corresponding symmetry of their focusing and defocusing diffraction orders. Fresnel zone plates with asymmetric structure profiles can break this limitation; yet existing implementations compromise either on resolution, ease of use, or stability. We present a new way for the fabrication of such blazed lenses by patterning two complementary binary Fresnel zone plates on the front and back sides of the same membrane chip to provide a compact, inherently stable, single-chip device. The presented blazed double-sided zone plates with 200 nm smallest half-pitch provide up to 54.7% focusing efficiency at 6.2 keV, which is clearly beyond the value obtainable by their binary counterparts.

Power calculation of grading device in desintegrator

NASA Astrophysics Data System (ADS)

Bogdanov, V. S.; Semikopenko, I. A.; Vavilov, D. V.

2018-03-01

This article describes the analytical method of measuring the secondary power consumption, necessitated by the installation of a grading device in the peripheral part of the grinding chamber in the desintegrator. There is a calculation model for defining the power input of the disintegrator increased by the extra power demand, required to rotate the grading device and to grind the material in the area between the external row of hammers and the grading device. The work has determined the inertia moments of a cylindrical section of the grading device with armour plates. The processing capacity of the grading device is adjusted to the conveying capacity of the auger feeder. The grading device enables one to increase the concentration of particles in the peripheral part of the grinding chamber and the amount of interaction between particles and armour plates as well as the number of colliding particles. The perforated sections provide the output of the ground material with the proper size granules, which together with the effects of armour plates, improves the efficiency of grinding. The power demand to rotate the grading device does not exceed the admissible value.

Ion-plating of solar cell arrays encapsulation task: LSA project 32

NASA Technical Reports Server (NTRS)

Volkers, J. C.

1983-01-01

An ion plating process by which solar cells can be metallized and AR coated, yielding efficiencies equal to or better than state-of-the-art cells, was developed. It was demonstrated that ion plated AR films may be used as an effective encapsulant, offering primary protection for the metallization. It was also shown that ion plated metallization and AR coatings can be consistent with the project cost goals.

Conventional versus digital radiographs for intraoperative cervical spine-level localization: a prospective time and cost analysis.

PubMed

Steinmetz, Michael P; Mroz, Thomas E; Krishnaney, Ajit; Modic, Michael

2009-12-01

In today's health-care environment, operational efficiency is intrinsic to balancing the need for increased productivity driven by rising costs and potentially decreasing reimbursement. Other operational factors kept constant, decreasing the time for a procedure can be viewed as one marker for increased efficiency. To prospectively evaluate the time and operating room efficiency differences between the two methods for intraoperative level localization. STYDY DESIGN: Prospective nonrandomized study. Prospective consecutive patients undergoing a single-level anterior cervical discectomy and fusion (ACDF) with plate and allograft. Time for performance and interpretation of intraoperative localization radiograph. This is a prospective nonrandomized study of patients treated consecutively with a single-level ACDF with allograft and plating. All the patients underwent a conventional approach to the cervical spine. After exposure, a spinal needle was placed in the exposed intervertebral disc and a radiography was performed. Either a conventional or a digital radiography was used in each case. Eighteen patients were enrolled in this study. Ten patients underwent localization with conventional radiography, whereas eight patients underwent localization with digital imaging. The mean time for conventional radiography was 823 seconds (standard deviation [SD], 159), and for digital, it was 100 seconds (SD, 34; p<.001). Current technology provides options for level localization. Digital imaging provides equally accurate information as conventional radiography in a significantly reduced amount of time. Image quality, ease or archival, and manipulation provided by digital radiography are superior to those by provided fluoroscopy. Keeping operational factors constant, decreasing the time for a procedure, and increasing the efficiency of the environment may be viewed as a surrogate for improving the cost basis for a procedure.

OH radicals generated by DC corona discharge for improving the pulsed discharge desulfuration efficiency.

PubMed

Li, Jie; Li, Guo-feng; Wu, Yan; Wang, Ning-hui; Huang, Qiu-nan

2004-01-01

Positive DC corona discharge is formed with needle-plate electrode configuration, in which the water vapor is ejected though the needle points. The purpose is to increase the numbers of the water-based radicals, ionize the water molecule and improve the desulfuration efficiency of pulsed corona reactor. The water ions were determined by four stages molecular beam mass spectrometer and diagnose the water-based radicals by emission spectrograph. A conclusion on formation of ions and radicals with DC corona discharges can be drawn.

Antimicrobial efficiency of ethanol and 2-propanol alcohols used on contaminated storage phosphor plates and impact on durability of the plate

PubMed Central

Wenzel, A; Kornum, F; Knudsen, MR; Lau, E Frandsen

2013-01-01

Objectives: To assess (1) antimicrobial efficiency of wiping intraoral phosphor plates with alcohol tissues based on ethanol or 2-propanol alcohols after contamination with Candida albicans and Streptococcus oralis, (2) a concept for autodisinfection with ultraviolet light of the transport ramp in a scanner for phosphor plates and (3) the impact of wiping with alcohol tissues on durability of the plate. Methods: Suspensions of C. albicans and S. oralis were prepared in concentrations of 109 and 105 organisms per ml, and Digora (Digora® Optime Imaging Plate, size 2; Soredex, PalaDEx Group Brenntag Nordic A/S, Hellerup, Denmark) and Vista (VistaScan® Imaging Plate PLUS, size 2; Dürr Dental AG, Bietigheim-Bissingen, Germany) plates were contaminated. The plates were wiped with ethanol or 2-propanol disinfectant tissues and imprints obtained on agar. Number of microbial colonies after culturing was recorded. The scanner ramp was contaminated with C. albicans or S. oralis, respectively, the ultraviolet light (UV light) disinfection in the scanner was activated and the number of colonies after culturing was recorded. Plates from each system were sequentially wiped (5–60 times) with ethanol and 2-propanol, exposed and scanned. 48 images from each system were scored blind: 1 = no artefact, 2 = small artefacts and 3 = severe artefacts. Results: Ethanol eliminated C. albicans and S. oralis in high and low concentrations from both types of plates, whereas 2-propanol did not eliminate all micro-organisms at high concentrations. The UV light eliminated all micro-organisms from the ramp. Ethanol degraded the plates to a larger extent than did 2-propanol. Images from Vista plates showed severe artefacts after wiping with ethanol; those from Digora plates did not. Conclusions: Ethanol eliminated all micro-organisms but degraded phosphor plates, whereas 2-propanol did not eliminate all micro-organisms and still degraded plates from Vista but not from Digora. PMID:23420856

Antimicrobial efficiency of ethanol and 2-propanol alcohols used on contaminated storage phosphor plates and impact on durability of the plate.

PubMed

Wenzel, A; Kornum, F; Knudsen, Mr; Lau, E Frandsen

2013-01-01

To assess (1) antimicrobial efficiency of wiping intraoral phosphor plates with alcohol tissues based on ethanol or 2-propanol alcohols after contamination with Candida albicans and Streptococcus oralis, (2) a concept for autodisinfection with ultraviolet light of the transport ramp in a scanner for phosphor plates and (3) the impact of wiping with alcohol tissues on durability of the plate. Suspensions of C. albicans and S. oralis were prepared in concentrations of 10(9) and 10(5) organisms per ml, and Digora (Digora(®) Optime Imaging Plate, size 2; Soredex, PalaDEx Group Brenntag Nordic A/S, Hellerup, Denmark) and Vista (VistaScan(®) Imaging Plate PLUS, size 2; Dürr Dental AG, Bietigheim-Bissingen, Germany) plates were contaminated. The plates were wiped with ethanol or 2-propanol disinfectant tissues and imprints obtained on agar. Number of microbial colonies after culturing was recorded. The scanner ramp was contaminated with C. albicans or S. oralis, respectively, the ultraviolet light (UV light) disinfection in the scanner was activated and the number of colonies after culturing was recorded. Plates from each system were sequentially wiped (5-60 times) with ethanol and 2-propanol, exposed and scanned. 48 images from each system were scored blind: 1 = no artefact, 2 = small artefacts and 3 = severe artefacts. Ethanol eliminated C. albicans and S. oralis in high and low concentrations from both types of plates, whereas 2-propanol did not eliminate all micro-organisms at high concentrations. The UV light eliminated all micro-organisms from the ramp. Ethanol degraded the plates to a larger extent than did 2-propanol. Images from Vista plates showed severe artefacts after wiping with ethanol; those from Digora plates did not. Ethanol eliminated all micro-organisms but degraded phosphor plates, whereas 2-propanol did not eliminate all micro-organisms and still degraded plates from Vista but not from Digora.

A study on EMI shielding enhancement behaviors of Ni-plated CFs-reinforced polymer matrix composites by post heat treatment

NASA Astrophysics Data System (ADS)

Kim, Kwan-Woo; Han, Woong; Kim, Byoung-Suhk; Kim, Byung-Joo; An, Kay-Hyeok

2017-09-01

In order to develop the high quality electromagnetic interference shielding efficiency (EMI-SE) materials, Ni-plated carbon fiber fabrics (Ni-CFFs) were prepared by an electroless method. Effects of post heat-treatment conditions on EMI-SE and electrical conductivity of Ni-CFFs/epoxy composites were also investigated. The morphologies and structural properties of Ni-CFFs were measured by a SEM and a XRD. It was found that all the Ni peaks increased with increasing post-heat treatment temperature, indicating that some impurities were removed and nickel particle sharp crystalline peaks. Also, It was found that the EMI-SE of composites enhanced was increased after post heat-treatment. In the frequency range of electromagnetic wave occurred from appliances (3.0 × 107-6.0 × 108), EMI-SE of post-heat treatment Ni-CFs was increased. This result concludes that the EMI-SE of the composites can be enhanced according to the microstructure of Ni in the Ni-CFFs/epoxy composites.

Effect of an Auxiliary Plate on Passive Heat Dissipation of Carbon Nanotube-Based Materials.

PubMed

Yu, Wei; Duan, Zheng; Zhang, Guang; Liu, Changhong; Fan, Shoushan

2018-03-14

Carbon nanotubes (CNTs) and other related CNT-based materials with a high thermal conductivity can be used as promising heat dissipation materials. Meanwhile, the miniaturization and high functionality of portable electronics, such as laptops and mobile phones, are achieved at the cost of overheating the high power-density components. The heat removal for hot spots occurring in a relatively narrow space requires simple and effective cooling methods. Here, an auxiliary passive cooling approach by the aid of a flat plate (aluminum-magnesium alloy) is investigated to accommodate heat dissipation in a narrow space. The cooling efficiency can be raised to 43.5%. The cooling performance of several CNT-based samples is compared under such circumstances. Heat dissipation analyses show that, when there is a nearby plate for cooling assistance, the heat radiation is weakened and natural convection is largely improved. Thus, improving heat radiation by increasing emissivity without reducing natural convection can effectively enhance the cooling performance. Moreover, the decoration of an auxiliary cooling plate with sprayed CNTs can further improve the cooling performance of the entire setup.

Theoretical analysis of terahertz generation from a compact optical parametric oscillator based on adhesive-free-bonded periodically inverted KTiOPO4 plates

NASA Astrophysics Data System (ADS)

Li, Zhongyang; Wang, Silei; Wang, Mengtao; Yuan, Bin; Wang, Weishu

2017-10-01

Terahertz (THz) generation by difference frequency generation (DFG) processes with dual signal waves is theoretically analyzed. The dual signal waves are generated by an optical parametric oscillator (OPO) with periodically inverted KTiOPO4 (KTP) plates based on adhesive-free-bonded (AFB) technology. The phase-matching conditions in a same AFB KTP composite for the OPO generating signals and idlers and for the DFG generating THz wave can be simultaneously satisfied by selecting the thickness of each KTP plate. Moreover, 4-order cascaded DFG processes can be realized in the same AFB KTP composite. The cascaded Stokes interaction processes generating THz photons and the cascaded anti-Stokes interaction processes consuming THz photons are investigated from coupled wave equations. Take an example of 3.106 THz which locates in the vicinity of polariton resonances, THz intensities and quantum conversion efficiencies are calculated. Compared with non-cascaded DFG processes, THz intensities of 3.106 THz in 4-order cascaded DFG processes increase to 5.56 times. When the pump intensity equals 20 MW mm-2, the quantum conversion efficiency of 259% in 4-order cascaded DFG processes can be realized, which exceeds the Manley-Rowe limit.

Efficient adhesion-based plasma membrane isolation for cell surface N-glycan analysis.

PubMed

Mun, Ji-Young; Lee, Kyung Jin; Seo, Hoon; Sung, Min-Sun; Cho, Yee Sook; Lee, Seung-Goo; Kwon, Ohsuk; Oh, Doo-Byoung

2013-08-06

Glycans, which decorate cell surfaces, play crucial roles in various physiological events involving cell surface recognition. Despite the importance of surface glycans, most analyses have been performed using total cells or whole membranes rather than plasma membranes due to difficulties related to isolation. In the present study, we employed an adhesion-based method for plasma membrane isolation to analyze N-glycans on cell surfaces. Cells were attached to polylysine-coated glass plates and then ruptured by hypotonic pressure. After washing to remove intracellular organelles, only a plasma membrane fraction remained attached to the plates, as confirmed by fluorescence imaging using organelle-specific probes. The plate was directly treated with trypsin to digest and detach the glycoproteins from the plasma membrane. From the resulting glycopeptides, N-glycans were released and analyzed using MALDI-TOF mass spectrometry and HPLC. When N-glycan profiles obtained by this method were compared to those by other methods, the amount of high-mannose type glycans mainly contaminated from the endoplasmic reticulum was dramatically reduced, which enabled the efficient detection of complex type glycans present on the cell surface. Moreover, this method was successfully used to analyze the increase of high-mannose glycans on the surface as induced by a mannosidase inhibitor treatment.

Fused-core particle technology as an alternative to sub-2-microm particles to achieve high separation efficiency with low backpressure.

PubMed

Cunliffe, Jennifer M; Maloney, Todd D

2007-12-01

Fused-Core particles have recently been introduced as an alternative to using sub-2-microm particles in chromatographic separations. Fused-Core particles are composed of a 1.7 microm solid core surrounded by a 0.5 microm porous silica layer (d(p) = 2.7 microm) to reduce mass transfer and increase peak efficiency. The performance of two commercially available Fused-Core particles (Advanced Materials Technology Halo C18 and Supelco Ascentis Express C18) was compared with sub-2-microm particles from Waters, Agilent, and Thermo Scientific. Although the peak efficiencies were only approximately 80% of those obtained by the Waters Acquity particles, the 50% lower backpressure allowed columns to be coupled in series to increase peak efficiency to 92,750 plates. The low backpressure and high efficiencies of the Fused-Core particles offer a viable alternative to using sub-2-microm particles and very-high-pressure LC instrumentation.

A review of the current state of digital plate reading of cultures in clinical microbiology.

PubMed

Rhoads, Daniel D; Novak, Susan M; Pantanowitz, Liron

2015-01-01

Digital plate reading (DPR) is increasingly being adopted as a means to facilitate the analysis and improve the quality and efficiency within the clinical microbiology laboratory. This review discusses the role of DPR in the context of total laboratory automation and explores some of the platforms currently available or in development for digital image capturing of microbial growth on media. The review focuses on the advantages and challenges of DPR. Peer-reviewed studies describing the utility and quality of these novel DPR systems are largely lacking, and professional guidelines for DPR implementation and quality management are needed. Further development and more widespread adoption of DPR is anticipated.

A review of the current state of digital plate reading of cultures in clinical microbiology

PubMed Central

Rhoads, Daniel D.; Novak, Susan M.; Pantanowitz, Liron

2015-01-01

Digital plate reading (DPR) is increasingly being adopted as a means to facilitate the analysis and improve the quality and efficiency within the clinical microbiology laboratory. This review discusses the role of DPR in the context of total laboratory automation and explores some of the platforms currently available or in development for digital image capturing of microbial growth on media. The review focuses on the advantages and challenges of DPR. Peer-reviewed studies describing the utility and quality of these novel DPR systems are largely lacking, and professional guidelines for DPR implementation and quality management are needed. Further development and more widespread adoption of DPR is anticipated. PMID:26110091

Transparent Solar Concentrator for Flat Panel Display

NASA Astrophysics Data System (ADS)

Yeh, Chia-Hung; Chang, Fuh-Yu; Young, Hong-Tsu; Hsieh, Tsung-Yen; Chang, Chia-Hsiung

2012-06-01

A new concept of the transparent solar concentrator for flat panel display is experimentally demonstrated without adversely affecting the visual effects. The solar concentrator is based on a solar light-guide plate with micro prisms, not only increasing the absorption area of solar energy but also enhancing the conversion efficiency. The incident light is guided by the designed solar light-guide plate according to the total internal reflection (TIR), and converted into electrical power by photovoltaic solar cells. The designed transparent solar concentrator was made and measured with high transparency, namely 94.8%. The developed solar energy system for display can store energy and supply the bias voltage to light on two light-emitting diodes (LEDs) successfully.

Computed Tomography and Thermography Increases CMC Material and Process Development Efficiency and Testing Effectiveness

NASA Technical Reports Server (NTRS)

Effinger, Michael; Beshears, Ron; Hufnagle, David; Walker, James; Russell, Sam; Stowell, Bob; Myers, David

2002-01-01

Nondestructive characterization techniques have been used to steer development and testing of CMCs. Computed tomography is used to determine the volumetric integrity of the CMC plates and components. Thermography is used to determine the near surface integrity of the CMC plates and components. For process and material development, information such as density uniformity, part delamination, and dimensional tolerance conformity is generated. The information from the thermography and computed tomography is correlated and then specimen cutting maps are superimposed on the thermography images. This enables for tighter data and potential explanation of off nominal test data. Examples of nondestructive characterization utilization to make decisions in process and material development and testing are presented.

Evaluation of All-Day-Efficiency for selected flat plate and evacuated tube collectors

NASA Technical Reports Server (NTRS)

1981-01-01

An evaluation of all day efficiency for selected flat plate and evacuated tube collectors is presented. Computations are based on a modified version of the NBSIR 78-1305A procedure for all day efficiency. The ASHMET and NOAA data bases for solar insolation are discussed. Details of the algorithm used to convert total (global) horizontal radiation to the collector tilt plane of the selected sites are given along with tables and graphs which show the results of the tests performed during this evaluation.

Volume holographic elements in Kodak 131 plates processed with SHSG method

NASA Astrophysics Data System (ADS)

Collados, Manuel V.; Atencia, Jesus; Lopez, Ana M.; Quintanilla, Manuel M.

2001-08-01

A SHSG procedure to register volume phase holograms in Kodak 131 plates is presented. We analyze the influence on the diffraction efficiency of the developing step and the temperature of the bleaching bath of usual SHSG processes. Applying a simple 12 steps process to form phase transmission holograms developing with D-19, bleaching with R-10 at 70 degrees C and removing the sensitizing dyes that remain in the emulsion with a diluted methanol bath after the fixation step, we obtain relative efficiencies of 100 percent and effective efficiencies of 70 percent.

The effects of leaf size and microroughness on the branch-scale collection efficiency of ultrafine particles

DOE PAGES

Huang, C. W.; Lin, M. Y.; Khlystov, A.; ...

2015-03-02

In this study, wind tunnel experiments were performed to explore how leaf size and leaf microroughness impact the collection efficiency of ultrafine particles (UFP) at the branch scale. A porous media model previously used to characterize UFP deposition onto conifers (Pinus taeda and Juniperus chinensis) was employed to interpret these wind tunnel measurements for four different broadleaf species (Ilex cornuta, Quercus alba, Magnolia grandiflora, and Lonicera fragrantissima) and three wind speed (0.3–0.9 ms -1) conditions. Among the four broadleaf species considered, Ilex cornuta with its partially folded shape and sharp edges was the most efficient at collecting UFP followed bymore » the other three flat-shaped broadleaf species. The findings here suggest that a connection must exist between UFP collection and leaf dimension and roughness. This connection is shown to be primarily due to the thickness of a quasi-laminar boundary layer pinned to the leaf surface assuming the flow over a leaf resembles that of a flat plate. A scaling analysis that utilizes a three-sublayer depositional model for a flat plate of finite size and roughness embedded within the quasi-laminar boundary layer illustrates these connections. The analysis shows that a longer leaf dimension allows for thicker quasi-laminar boundary layers to develop. A thicker quasi-laminar boundary layer depth in turn increases the overall resistance to UFP deposition due to an increase in the diffusional path length thereby reducing the leaf-scale UFP collection efficiency. Finally, it is suggested that the effects of leaf microroughness are less relevant to the UFP collection efficiency than are the leaf dimensions for the four broadleaf species explored here.« less

The effects of leaf size and microroughness on the branch-scale collection efficiency of ultrafine particles

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

Huang, C. W.; Lin, M. Y.; Khlystov, A.

In this study, wind tunnel experiments were performed to explore how leaf size and leaf microroughness impact the collection efficiency of ultrafine particles (UFP) at the branch scale. A porous media model previously used to characterize UFP deposition onto conifers (Pinus taeda and Juniperus chinensis) was employed to interpret these wind tunnel measurements for four different broadleaf species (Ilex cornuta, Quercus alba, Magnolia grandiflora, and Lonicera fragrantissima) and three wind speed (0.3–0.9 ms -1) conditions. Among the four broadleaf species considered, Ilex cornuta with its partially folded shape and sharp edges was the most efficient at collecting UFP followed bymore » the other three flat-shaped broadleaf species. The findings here suggest that a connection must exist between UFP collection and leaf dimension and roughness. This connection is shown to be primarily due to the thickness of a quasi-laminar boundary layer pinned to the leaf surface assuming the flow over a leaf resembles that of a flat plate. A scaling analysis that utilizes a three-sublayer depositional model for a flat plate of finite size and roughness embedded within the quasi-laminar boundary layer illustrates these connections. The analysis shows that a longer leaf dimension allows for thicker quasi-laminar boundary layers to develop. A thicker quasi-laminar boundary layer depth in turn increases the overall resistance to UFP deposition due to an increase in the diffusional path length thereby reducing the leaf-scale UFP collection efficiency. Finally, it is suggested that the effects of leaf microroughness are less relevant to the UFP collection efficiency than are the leaf dimensions for the four broadleaf species explored here.« less

Numerical simulation of the supersonic boundary layer interaction with arbitrary oriented acoustic waves

NASA Astrophysics Data System (ADS)

Semenov, A. N.; Gaponov, S. A.

2017-10-01

Based the direct numerical simulation in the paper the supersonic flow around of the infinitely thin plate, which was perturbed by the acoustic wave, was investigated. Calculations carried out in the case of small perturbations at the Mach number M=2 and Reynold's numbers Re<600. It is established that the velocity perturbation amplitude within the boundary layer is greater than the amplitude of the external acoustic wave in several times, the maximum amplitude growth is reached 10. At the small sliding and incidence angles the velocity perturbations amplitude increased monotonously with Reynold's numbers. At rather great values of these angles there are maxima in dependences of the velocity perturbations amplitude on the Reynold's number. The oscillations exaltation in the boundary layer by the sound wave more efficiently if the plate is irradiated from above. At the fixed Reynolds's number and frequency there are critical values of the sliding and incidence angles (χ, φ) at which the disturbances excited by a sound wave are maxima. At M=2 it takes place at χ≈ φ ≈30°. The excitation efficiency of perturbations in the boundary layer increases with the Mach number, and it decreases with a frequency.

High-dose neutron detector project update

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

Menlove, Howard Olsen; Henzlova, Daniela

These are the slides for a progress review meeting by the sponsor. This is an update on the high-dose neutron detector project. In summary, improvements in both boron coating and signal amplification have been achieved; improved boron coating materials and procedures have increased efficiency by ~ 30-40% without the corresponding increase in the detector plate area; low dead-time via thin cell design (~ 4 mm gas gaps) and fast amplifiers; prototype PDT 8” pod has been received and testing is in progress; significant improvements in efficiency and stability have been verified; use commercial PDT 10B design and fabrication to obtainmore » a faster path from the research to practical high-dose neutron detector.« less

Evolution of Plate Tectonics on Earth since the Mid-Mesoarchean was Controlled by Sedimentary Fluxes from Continents to Oceans and Mantle Temperature

NASA Astrophysics Data System (ADS)

Sobolev, S. V.; Brown, M.

2017-12-01

Plate tectonics (PT) is the most important geological process operating on Earth, making it unique among the rocky planets in the Solar System. The question of how PT was initiated and which factors controlled its evolution over Earth's history are widely discussed, but remain controversial. It is broadly accepted that a necessary condition for initiation and stable operation of PT is maintaining low strength along plate boundaries, particularly along the subduction zone interfaces in the subduction channels. Examples from the South American Andes and other convergent margins show that unconsolidated continental sediments in trenches serve as an efficient lubricant for subduction; if these are lacking, friction in the subduction channel and strength of the plate boundary are significantly increased. We suggest that lubrication of subduction by accumulation of continental sediments in trenches played a crucial role during the evolution of PT on Earth since the mid-Mesoarchean. We posit that continental emergence and enhanced surface erosion caused an increasing flux of sediments into the oceans, which in turn lubricated subduction channels and intensified PT. Thus, peaks in orogenesis, as confirmed by several proxies, during periods of supercraton/supercontinent assembly represent periods of vigorous subduction and continental sedimentation in trenches prior to terminal collision. Conversely, a decrease in plate boundary length and a reduction in continental sediment accumulation in trenches during periods of stability after supercraton/supercontinent assembly is the likely reason for periods of lower PT vigor, including the so called `boring billion' between 1.8 and 0.8 Ga. The largest surface erosion and subduction-lubrication event occurred at the end of the `snowball' Earth epoch in the Neoproterozoic and likely accelerated the most recent episode of vigorous PT. Based on analysis of various geological observations, we suggest that the cyclic behavior of PT on Earth since the mid-Mesoarchean (the so-called `supercontinent cycle') can be interpreted in terms of the balance of power between PT, driven by slab pull and controlled by the temperature of the upper mantle, and the efficiency of lubrication in the subduction zones, controlled by accumulation of continental sediment in the trenches.

Spectrally formulated user-defined element in conventional finite element environment for wave motion analysis in 2-D composite structures

NASA Astrophysics Data System (ADS)

Khalili, Ashkan; Jha, Ratneshwar; Samaratunga, Dulip

2016-11-01

Wave propagation analysis in 2-D composite structures is performed efficiently and accurately through the formulation of a User-Defined Element (UEL) based on the wavelet spectral finite element (WSFE) method. The WSFE method is based on the first-order shear deformation theory which yields accurate results for wave motion at high frequencies. The 2-D WSFE model is highly efficient computationally and provides a direct relationship between system input and output in the frequency domain. The UEL is formulated and implemented in Abaqus (commercial finite element software) for wave propagation analysis in 2-D composite structures with complexities. Frequency domain formulation of WSFE leads to complex valued parameters, which are decoupled into real and imaginary parts and presented to Abaqus as real values. The final solution is obtained by forming a complex value using the real number solutions given by Abaqus. Five numerical examples are presented in this article, namely undamaged plate, impacted plate, plate with ply drop, folded plate and plate with stiffener. Wave motions predicted by the developed UEL correlate very well with Abaqus simulations. The results also show that the UEL largely retains computational efficiency of the WSFE method and extends its ability to model complex features.

Guided wave propagation in metallic and resin plates loaded with water on single surface

NASA Astrophysics Data System (ADS)

Hayashi, Takahiro; Inoue, Daisuke

2016-02-01

Our previous papers reported dispersion curves for leaky Lamb waves in a water-loaded plate and wave structures for several typical modes including quasi-Scholte waves [1,2]. The calculations were carried out with a semi-analytical finite element (SAFE) method developed for leaky Lamb waves. This study presents SAFE calculations for transient guided waves including time-domain waveforms and animations of wave propagation in metallic and resin water-loaded plates. The results show that non-dispersive and non-attenuated waves propagating along the interface between the fluid and the plate are expected for effective non-destructive evaluation of such fluid-loaded plates as storage tanks and transportation pipes. We calculated transient waves in both steel and polyvinyl chloride (PVC) plates loaded with water on a single side and input dynamic loading from a point source on the other water-free surface as typical examples of metallic and resin plates. For a steel plate, there exists a non-dispersive and non-attenuated mode, called the quasi-Scholte wave, having an almost identical phase velocity to that of water. The quasi-Scholte wave has superior generation efficiency in the low frequency range due to its broad energy distribution across the plate, whereas it is localized near the plate-water interface at higher frequencies. This means that it has superior detectability of inner defects. For a PVC plate, plural non-attenuated modes exist. One of the non-attenuated modes similar to the A0 mode of the Lamb wave in the form of a group velocity dispersion curve is promising for the non-destructive evaluation of the PVC plate because it provides prominent characteristics of generation efficiency and low dispersion.

Kinetic efficiency of polar monolithic capillary columns in high-pressure gas chromatography.

PubMed

Kurganov, A A; Korolev, A A; Shiryaeva, V E; Popova, T P; Kanateva, A Yu

2013-11-08

Poppe plots were used for analysis of kinetic efficiency of monolithic sorbents synthesized in quartz capillaries for utilization in high-pressure gas chromatography. Values of theoretical plate time and maximum number of theoretical plates occurred to depend significantly on synthetic parameters such as relative amount of monomer in the initial polymerization mixture, temperature and polymerization time. Poppe plots let one to find synthesis conditions suitable either for high-speed separations or for maximal efficiency. It is shown that construction of kinetic Poppe curves using potential Van Deemter data demands compressibility of mobile phase to be taken into consideration in the case of gas chromatography. Model mixture of light hydrocarbons C1 to C4 was then used for investigation of influence of carrier gas nature on kinetic efficiency of polymeric monolithic columns. Minimal values of theoretical plate times were found for CO2 and N2O carrier gases. Copyright © 2013 Elsevier B.V. All rights reserved.

A high-efficiency tunable TEM-TE11 mode converter for high-power microwave applications

NASA Astrophysics Data System (ADS)

Wang, Xiao-Yu; Fan, Yu-Wei; Shu, Ting; Yuan, Cheng-wei; Zhang, Qiang

2017-03-01

The tunable high power microwave source (HPM's) is considered to be an important research direction. However, the corresponding mode converter has been researched little. In this paper, a high-efficiency tunable mode converter (HETMC) is investigated for high-power microwave applications. The HETMC that is consisted of coaxial inner and outer conductors, with four metal plates arranged radially, at 90° in the coaxial gap, and matching rods can transform coaxial transverse electromagnetic (TEM) mode to TE11 coaxial waveguide mode. The results show that adjusting the length of the downstream plate, and the distance between the rods installed upstream and the closest edges of the plates, can improve the conversion efficiency and bandwidth remarkably. Moreover, when the frequency ranges from 1.63 GHz to 2.12 GHz, the conversion efficiency is above 95% between 1.63 GHz and 2.12 GHz with a bandwidth of 26.1%. Besides, the unwished reflection and transmission can be eliminated effectively in the HETMC.

Large Area and High Efficiency Photon Counting Imaging Detectors with High Time and Spatial Resolution for Night Time Sensing and Astronomy

NASA Astrophysics Data System (ADS)

Siegmund, O.; Vallerga, J.; Tremsin, A.; McPhate, J.; Frisch, H.; Elam, J.; Mane, A.; Wagner, R.; Varner, G.

2012-09-01

The development of large area photon counting, imaging, timing detectors with high performance has significance for applications in astronomy (such as our sensor on the SAAO SALT 10m telescope), night time remote reconnaissance, airborne/space situational awareness, and high-speed adaptive optics. Sealed tube configurations for optical/IR sensing also have applications in detection of Cherenkov light (RICH), biological single-molecule fluorescence lifetime imaging microscopy and neutron imaging applications. In open faced configurations these devices are important for UV and particle detection in space astrophysics, mass spectroscopy and many time-of flight applications. Currently available devices are limited to sizes of about 5 cm and use either conventional microchannel plates, or dynode multipliers for amplification, coupled coarse pad array readouts. Extension of these schemes to devices as large as 20 cm with high spatial resolution presents significant problems and potentially considerable cost. A collaboration (Large Area Picosecond Photon Detector) of the U. Chicago, Argonne National Laboratory, U.C. Berkeley, U. Hawaii and a number of other institutions has developed novel technologies to realize 20 cm format detectors in open face or sealed tube configurations. One critical component of this development is novel microchannel plates employing borosilicate micro-capillary arrays. The microchannel plates are based on a novel concept where the substrate is constructed from a borosilicate micro-capillary array that is made to function as a microchannel plate by deposition of resistive and secondary emissive layers using atomic layer deposition. The process is relatively inexpensive compared with conventional microchannel plates and allows very large microchannel plates to be produced with pore sizes as small as 10 microns. These provide many performance characteristics typical of conventional microchannel plates, but have been made in sizes up to 20 cm, have low intrinsic background (<0.1 events/sq-cm/sec) and high stability with no observed gain degradation behavior over at least 5 Coul/sq-cm of charge extraction. Initial tests in a 20 cm detector with a cross strip electronic readout have achieved 4k x 4k pixel imaging with single photon sub-ns timing and MHz event rates. In concert with this effort we have made stable, uniform 20 cm bialkali photocathodes with >20% quantum efficiency on borosilicate windows compatible with a large sealed tube device. Other related efforts have also produced small sealed tubes with 30% quantum efficiency GaAs sealed tubes with high resolution imaging and timing that are immediately applicable to current applications, and opaque GaN UV photocathodes directly deposited onto these novel microchannel plates. We will discuss the details and implications of these novel microchannel plates with respect to the realization of novel detectors up to 20 cm format with reasonable cost and performance, robust construction, high flexibility of format and readout, reduction of fabrication effort, dramatically increased lifetime and stability, and their potential applications.

SubductionGenerator: A program to build three-dimensional plate configurations

NASA Astrophysics Data System (ADS)

Jadamec, M. A.; Kreylos, O.; Billen, M. I.; Turcotte, D. L.; Knepley, M.

2016-12-01

Geologic, geochemical, and geophysical data from subduction zones indicate that a two-dimensional paradigm for plate tectonic boundaries is no longer adequate to explain the observations. Many open source software packages exist to simulate the viscous flow of the Earth, such as the dynamics of subduction. However, there are few open source programs that generate the three-dimensional model input. We present an open source software program, SubductionGenerator, that constructs the three-dimensional initial thermal structure and plate boundary structure. A 3D model mesh and tectonic configuration are constructed based on a user specified model domain, slab surface, seafloor age grid file, and shear zone surface. The initial 3D thermal structure for the plates and mantle within the model domain is then constructed using a series of libraries within the code that use a half-space cooling model, plate cooling model, and smoothing functions. The code maps the initial 3D thermal structure and the 3D plate interface onto the mesh nodes using a series of libraries including a k-d tree to increase efficiency. In this way, complicated geometries and multiple plates with variable thickness can be built onto a multi-resolution finite element mesh with a 3D thermal structure and 3D isotropic shear zones oriented at any angle with respect to the grid. SubductionGenerator is aimed at model set-ups more representative of the earth, which can be particularly challenging to construct. Examples include subduction zones where the physical attributes vary in space, such as slab dip and temperature, and overriding plate temperature and thickness. Thus, the program can been used to construct initial tectonic configurations for triple junctions and plate boundary corners.

Analysis of bending wave transmission using beam tracing with advanced statistical energy analysis for periodic box-like structures affected by spatial filtering

NASA Astrophysics Data System (ADS)

Wilson, D.; Hopkins, C.

2015-04-01

For bending wave transmission across periodic box-like arrangements of plates, the effects of spatial filtering can be significant and this needs to be considered in the choice of prediction model. This paper investigates the errors that can occur with Statistical Energy Analysis (SEA) and the potential of using Advanced SEA (ASEA) to improve predictions. The focus is on the low- and mid-frequency range where plates only support local modes with low mode counts and the in situ modal overlap is relatively high. To increase the computational efficiency when using ASEA on large systems, a beam tracing method is introduced which groups together all rays with the same heading into a single beam. Based on a diffuse field on the source plate, numerical experiments are used to determine the angular distribution of incident power on receiver plate edges on linear and cuboid box-like structures. These show that on receiver plates which do not share a boundary with the source plate, the angular distribution on the receiver plate boundaries differs significantly from a diffuse field. SEA and ASEA predictions are assessed through comparison with finite element models. With rain-on-the-roof excitation on the source plate, the results show that compared to SEA, ASEA provides significantly better estimates of the receiver plate energy, but only where there are at least one or two bending modes in each one-third octave band. Whilst ASEA provides better accuracy than SEA, discrepancies still exist which become more apparent when the direct propagation path crosses more than three nominally identical structural junctions.

Efficient finite element modelling for the investigation of the dynamic behaviour of a structure with bolted joints

NASA Astrophysics Data System (ADS)

Omar, R.; Rani, M. N. Abdul; Yunus, M. A.; Mirza, W. I. I. Wan Iskandar; Zin, M. S. Mohd

2018-04-01

A simple structure with bolted joints consists of the structural components, bolts and nuts. There are several methods to model the structures with bolted joints, however there is no reliable, efficient and economic modelling methods that can accurately predict its dynamics behaviour. Explained in this paper is an investigation that was conducted to obtain an appropriate modelling method for bolted joints. This was carried out by evaluating four different finite element (FE) models of the assembled plates and bolts namely the solid plates-bolts model, plates without bolt model, hybrid plates-bolts model and simplified plates-bolts model. FE modal analysis was conducted for all four initial FE models of the bolted joints. Results of the FE modal analysis were compared with the experimental modal analysis (EMA) results. EMA was performed to extract the natural frequencies and mode shapes of the test physical structure with bolted joints. Evaluation was made by comparing the number of nodes, number of elements, elapsed computer processing unit (CPU) time, and the total percentage of errors of each initial FE model when compared with EMA result. The evaluation showed that the simplified plates-bolts model could most accurately predict the dynamic behaviour of the structure with bolted joints. This study proved that the reliable, efficient and economic modelling of bolted joints, mainly the representation of the bolting, has played a crucial element in ensuring the accuracy of the dynamic behaviour prediction.

Optimization and experimental validation of stiff porous phononic plates for widest complete bandgap of mixed fundamental guided wave modes

NASA Astrophysics Data System (ADS)

Hedayatrasa, Saeid; Kersemans, Mathias; Abhary, Kazem; Uddin, Mohammad; Van Paepegem, Wim

2018-01-01

Phononic crystal plates (PhPs) have promising application in manipulation of guided waves for design of low-loss acoustic devices and built-in acoustic metamaterial lenses in plate structures. The prominent feature of phononic crystals is the existence of frequency bandgaps over which the waves are stopped, or are resonated and guided within appropriate defects. Therefore, maximized bandgaps of PhPs are desirable to enhance their phononic controllability. Porous PhPs produced through perforation of a uniform background plate, in which the porous interfaces act as strong reflectors of wave energy, are relatively easy to produce. However, the research in optimization of porous PhPs and experimental validation of achieved topologies has been very limited and particularly focused on bandgaps of flexural (asymmetric) wave modes. In this paper, porous PhPs are optimized through an efficient multiobjective genetic algorithm for widest complete bandgap of mixed fundamental guided wave modes (symmetric and asymmetric) and maximized stiffness. The Pareto front of optimization is analyzed and variation of bandgap efficiency with respect to stiffness is presented for various optimized topologies. Selected optimized topologies from the stiff and compliant regimes of Pareto front are manufactured by water-jetting an aluminum plate and their promising bandgap efficiency is experimentally observed. An optimized Pareto topology is also chosen and manufactured by laser cutting a Plexiglas (PMMA) plate, and its performance in self-collimation and focusing of guided waves is verified as compared to calculated dispersion properties.

Performance Analysis of a Self-Propelling Flat Plate Fin with Joint Compliance

NASA Astrophysics Data System (ADS)

Reddy, N. Srinivasa; Sen, Soumen; Pal, Sumit; Shome, Sankar Nath

2017-12-01

Fish fin muscles are compliant and they regulate the stiffness to suit different swimming conditions. This article attempts to understand the significance of presence of compliance in fin muscle with help of a flexible joint flat plate fin model. Blade element method is employed to model hydrodynamics and to compute the forces of interaction during motion of the plate within fluid. The dynamic model of self-propelling fin is developed through multi-body dynamics approach considering the hydrodynamic forces as external forces acting on the fin. The derived hydrodynamic model is validated with experiments on rigid flat plate fin. The effect of the joint stiffness and flapping frequency on the propulsion speed and efficiency is investigated through simulations using the derived and validated model. The propulsion efficiency is found to be highly influenced by the joint stiffness at a given flapping frequency. The fin attained maximum propulsion efficiency when the joint stiffness is tuned to a value at which flapping frequency matches near natural frequency of the fin. At this tuned joint stiffness and flapping frequency, the resulted Strouhal numbers are observed to fall within the optimum range (0.2 to 0.4) for maximized propulsion efficiency of flying birds and swimming aquatic animals reported in literature.

Efficiency in supercritical fluid chromatography with different superficially porous and fully porous particles ODS bonded phases.

PubMed

Lesellier, E

2012-03-09

The chromatographic efficiency, in terms of plate number per second, was dramatically improved by the introduction of sub-two microns particles with ultra-high pressure liquid chromatography (UHPLC). On the other hand, the recent development of superficially porous particles, called core-shell or fused-core particles, appears to allow the achievement of the same efficiency performances at higher speed without high pressure drops. CO₂-based mobile phases exhibiting much lower viscosities than aqueous based mobile phases allow better theoretical efficiencies, even with 3-5 μm particles, but with relative low pressure drops. They also allow much higher flow rates or much longer columns while using conventional instruments capable to operate below 400 bar. Moreover, the use of superficially porous particles in SFC could enhance the chromatographic performances even more. The kinetic behavior of ODS phases bonded on these particles was studied, with varied flow rates, outlet (and obviously inlet) pressures, temperatures, by using a homologous series (alkylbenzenes) with 10% modifier (methanol or acetonitrile) in the carbon dioxide mobile phase. Results were also compared with classical fully porous particles, having different sizes, from 2.5 to 5 μm. Superior efficiency (N) and reduced h were obtained with these new ODS-bonded particles in regards to classical ones, showing their great interest for use in SFC. However, surprising behavior were noticed, i.e. the increase of the theoretical plate number vs. the increase of the chain length of the compounds. This behavior, opposite to the one classically reported vs. the retention factor, was not depending on the outlet pressure, but on the flow rate and the temperature changes. The lower radial trans-column diffusion on this particle types could explain these results. This diffusion reduction with these ODS-bonded superficially porous particles seems to decrease with the increase of the residence time of compounds. Copyright © 2011 Elsevier B.V. All rights reserved.

Innovative design of composite structures: Use of curvilinear fiber format to improve structural efficiency

NASA Technical Reports Server (NTRS)

Hyer, M. W.; Charette, R. F.

1987-01-01

To increase the effectiveness and efficiency of fiber-reinforced materials, the use of fibers in a curvilinear rather than the traditional straightline format is explored. The capacity of a laminated square plate with a central circular hole loaded in tension is investigated. The orientation of the fibers is chosen so that the fibers in a particular layer are aligned with the principle stress directions in that layer. Finite elements and an iteration scheme are used to find the fiber orientation. A noninteracting maximum strain criterion is used to predict load capacity. The load capacities of several plates with different curvilinear fibers format are compared with the capacities of more conventional straightline format designs. It is found that the most practical curvilinear design sandwiches a group of fibers in a curvilinear format between a pair of +/-45 degree layers. This design has a 60% greater load capacity than a conventional quasi-isotropic design with the same number of layers. The +/-45 degree layers are necessary to prevent matrix cracking in the curvilinear layers due to stresses perpendicular to the fibers in those layers. Greater efficiencies are achievable with composite structures than now realized.

A model for the Global Quantum Efficiency for a TPB-based wavelength-shifting system used with photomultiplier tubes in liquid argon in MicroBooNE

NASA Astrophysics Data System (ADS)

Pate, S. F.; Wester, T.; Bugel, L.; Conrad, J.; Henderson, E.; Jones, B. J. P.; McLean, A. I. L.; Moon, J. S.; Toups, M.; Wongjirad, T.

2018-02-01

We present a model for the Global Quantum Efficiency (GQE) of the MicroBooNE optical units. An optical unit consists of a flat, circular acrylic plate, coated with tetraphenyl butadiene (TPB), positioned near the photocathode of a 20.2-cm diameter photomultiplier tube. The plate converts the ultra-violet scintillation photons from liquid argon into visible-spectrum photons to which the cryogenic phototubes are sensitive. The GQE is the convolution of the efficiency of the plates that convert the 128 nm scintillation light from liquid argon to visible light, the efficiency of the shifted light to reach the photocathode, and the efficiency of the cryogenic photomultiplier tube. We develop a GEANT4-based model of the optical unit, based on first principles, and obtain the range of probable values for the expected number of detected photoelectrons (NPE) given the known systematic errors on the simulation parameters. We compare results from four measurements of the NPE determined using alpha-particle sources placed at two distances from a TPB-coated plate in a liquid argon cryostat test stand. We also directly measured the radial dependence of the quantum efficiency, and find that this has the same shape as predicted by our model. Our model results in a GQE of 0.0055±0.0009 for the MicroBooNE optical units. While the information shown here is MicroBooNE specific, the approach to the model and the collection of simulation parameters will be widely applicable to many liquid-argon-based light collection systems.

Absolute calibration of a multichannel plate detector for low energy O, O-, and O+

NASA Astrophysics Data System (ADS)

Stephen, T. M.; Peko, B. L.

2000-03-01

Absolute detection efficiencies of a commercial multichannel plate detector have been measured for O, O+, and O-, impacting at normal incidence for energies ranging from 30-1000 eV. In addition, the detection efficiencies for O relative to its ions are presented, as they may have a more universal application. The absolute detection efficiencies are strongly energy dependent and significant differences are observed for the various charge states at lower energies. The detection efficiencies for the different charge states appear to converge at higher energies. The strongest energy dependence is for O+; the detection efficiency varies by three orders of magnitude across the energy range studied. The weakest dependence is for O-, which varies less than one order of magnitude.

Thermal performances of vertical hybrid PV/T air collector

NASA Astrophysics Data System (ADS)

Tabet, I.; Touafek, K.; Bellel, N.; Khelifa, A.

2016-11-01

In this work, numerical analyses and the experimental validation of the thermal behavior of a vertical photovoltaic thermal air collector are investigated. The thermal model is developed using the energy balance equations of the PV/T air collector. Experimental tests are conducted to validate our mathematical model. The tests are performed in the southern Algerian region (Ghardaïa) under clear sky conditions. The prototype of the PV/T air collector is vertically erected and south oriented. The absorber upper plate temperature, glass cover temperature, air temperature in the inlet and outlet of the collector, ambient temperature, wind speed, and solar radiation are measured. The efficiency of the collector increases with increase in mass flow of air, but the increase in mass flow of air reduces the temperature of the system. The increase in efficiency of the PV/T air collector is due to the increase in the number of fins added. In the experiments, the air temperature difference between the inlet and the outlet of the PV/T air collector reaches 10 ° C on November 21, 2014, the interval time is between 10:00 and 14:00, and the temperature of the upper plate reaches 45 ° C at noon. The mathematical model describing the dynamic behavior of the typical PV/T air collector is evaluated by calculating the root mean square error and mean absolute percentage error. A good agreement between the experiment and the simulation results is obtained.

Interfacial stability and electrochemical behavior of Li/LiFePO4 batteries using novel soft and weakly adhesive photo-ionogel electrolytes

NASA Astrophysics Data System (ADS)

Aidoud, D.; Etiemble, A.; Guy-Bouyssou, D.; Maire, E.; Le Bideau, J.; Guyomard, D.; Lestriez, B.

2016-10-01

We have developed flexible polymer-gel electrolytes based on a polyacrylate cross-linked matrix that confines an ionic liquid doped with a lithium salt. Free-standing solid electrolyte membrane is obtained after UV photo-polymerization of acrylic monomers dissolved inside the ionic liquid/lithium salt mixture. The liquid precursor of the photo-ionogel may also be directly deposited onto porous composite electrode, which results in all-solid state electrode/electrolyte stacking after UV illumination. Minor variations in the polymer component of the electrolyte formulation significantly affect the electrochemical behavior in LiFePO4/lithium and lithium/lithium cells. The rate performance increases with an increase of the ionic conductivity, which decreases with the polymer content and decreases with increasing oxygen content in the polyacrylate matrix. Their fairly low modulus endow them weak and beneficial pressure-sensitive-adhesive character. X-Rays Tomography shows that the solid-state photo-ionogel electrolytes keep their integrity upon cycling and that their surface remains smooth. The coulombic efficiency of LiFePO4/lithium cells increases with an increase of the adhesive strength of the photo-ionogel, suggesting a relationship between the contact intimacy at the lithium/photo-ionogel interface and the efficiency of the lithium striping/plating. In lithium/lithium cells, only the photo-ionogels with the higher adhesion strength are able to allow the reversible striping/plating of lithium.

A novel combined method of osteosynthesis in treatment of tibial fractures: a comparative study on sheep with application of rod-through-plate fixator and bone plating.

PubMed

Tralman, G; Andrianov, V; Arend, A; Männik, P; Kibur, R T; Nõupuu, K; Uksov, D; Aunapuu, M

2013-04-01

The study compares the efficiency of a new bone fixator combining periostal and intramedullary osteosynthesis to bone plating in treatment of tibial fractures in sheep. Experimental osteotomies were performed in the middle third of the left tibia. Animals were divided into two groups: in one group (four animals) combined osteosynthesis (rod-through-plate fixator, RTP fixator) was applied, and in the other group (three animals) bone plating was used. The experiments lasted for 10 weeks during which fracture union was followed by radiography, and the healing process was studied by blood serum markers reflecting bone turnover and by histological and immunohistochemical investigations. In the RTP fixator group, animals started to load body weight on the operated limbs the next day after the surgery, while in the bone plating group, this happened only on the seventh day. In the RTP fixator group, consolidation of fractures was also faster, as demonstrated by radiographical, histological, and immunohistochemical investigations and in part by blood serum markers for bone formation. It can be concluded that application of RTP fixation is more efficient than plate fixation in the treatment of experimental osteotomies of long bones in sheep. © 2012 Blackwell Verlag GmbH.

The Thermal Collector With Varied Glass Covers

NASA Astrophysics Data System (ADS)

Luminosu, I.; Pop, N.

2010-08-01

The thermal collector with varied glass covers represents an innovation realized in order to build a collector able to reach the desired temperature by collecting the solar radiation from the smallest surface, with the highest efficiency. In the case of the thermal collector with variable cover glasses, the number of the glass plates covering the absorber increases together with the length of the circulation pipe for the working fluid. The thermal collector with varied glass covers compared to the conventional collector better meet user requirements because: for the same temperature increase, has the collecting area smaller; for the same collection area, realizes the highest temperature increase and has the highest efficiency. This works is addressed to researchers in the solar energy and to engineers responsible with air-conditioning systems design or industrial and agricultural products drying.

Development and Validation of a Novel LC-MS/MS Opioid Confirmation Assay: Evaluation of β-glucuronidase Enzymes and Sample Cleanup Methods.

PubMed

Yang, He S; Wu, Alan H B; Lynch, Kara L

2016-06-01

With the rise in the use and misuse of prescription opioids, there is an increasing need for the confirmed identification of opioid analgesics in toxicology laboratories. The goals of this study were to (i) systematically evaluate the hydrolysis efficiency of four β-glucuronidase enzymes under optimized condition; (ii) evaluate compound recovery, matrix effects and precision of three protein precipitation plates and (iii) develop and validate a qualitative liquid-chromatography mass spectrometry (LC-MS/MS) assay to identify 13 opioids in urine. A recombinant β-glucuronidase exhibited the best overall hydrolysis efficiency for seven opioid glucuronide conjugates compared with β-glucuronidase from red abalone, Escherichia coli and Patella vulgata One of the protein precipitation plates tested exhibited overall better recovery of the opioids and lower ion suppression compared with the other two plates. An ESI positive mode LC-MS/MS assay for qualitative opioid analysis was developed and validated. Linearity, LOD, precision, matrix effect, recovery, carryover and interference of the method were evaluated. Sixty-two patient samples were analyzed by both a legacy GC-MS opioid method and the LC-MS/MS method, and 22 samples were analyzed by the LC-MS/MS and an LC-MS/MS reference method. The results of the comparisons showed good concordance. Overall, we described an efficient sample preparation procedure for a sensitive qualitative opioid confirmation assay in urine. © The Author 2016. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

A Novel Computer-Aided Approach for Parametric Investigation of Custom Design of Fracture Fixation Plates.

PubMed

Chen, Xiaozhong; He, Kunjin; Chen, Zhengming

2017-01-01

The present study proposes an integrated computer-aided approach combining femur surface modeling, fracture evidence recover plate creation, and plate modification in order to conduct a parametric investigation of the design of custom plate for a specific patient. The study allows for improving the design efficiency of specific plates on the patients' femur parameters and the fracture information. Furthermore, the present approach will lead to exploration of plate modification and optimization. The three-dimensional (3D) surface model of a detailed femur and the corresponding fixation plate were represented with high-level feature parameters, and the shape of the specific plate was recursively modified in order to obtain the optimal plate for a specific patient. The proposed approach was tested and verified on a case study, and it could be helpful for orthopedic surgeons to design and modify the plate in order to fit the specific femur anatomy and the fracture information.

Complexing agent and heavy metal removals from metal plating effluent by electrocoagulation with stainless steel electrodes.

PubMed

Kabdaşli, Işik; Arslan, Tülin; Olmez-Hanci, Tuğba; Arslan-Alaton, Idil; Tünay, Olcay

2009-06-15

In the present study, the treatability of a metal plating wastewater containing complexed metals originating from the nickel and zinc plating process by electrocoagulation using stainless steel electrodes was experimentally investigated. The study focused on the effect of important operation parameters on electrocoagulation process performance in terms of organic complex former, nickel and zinc removals as well as sludge production and specific energy consumption. The results indicated that increasing the applied current density from 2.25 to 9.0 mA/cm(2) appreciably enhanced TOC removal efficiency from 20% to 66%, but a further increase in the applied current density to 56.25 mA/cm(2) did not accelerate TOC removal rates. Electrolyte concentration did not affect the process performance significantly and the highest TOC reduction (66%) accompanied with complete heavy metal removals were achieved at the original chloride content ( approximately 1500 mg Cl/L) of the wastewater sample. Nickel removal performance was adversely affected by the decrease of initial pH from its original value of 6. Optimum working conditions for electrocoagulation of metal plating effluent were established as follows: an applied current density of 9 mA/cm(2), the effluent's original electrolyte concentration and pH of the composite sample. TOC removal rates obtained for all electrocoagulation runs fitted pseudo-first-order kinetics very well (R(2)>92-99).

Efficient use of strong light for high photosynthetic productivity: interrelationships between the optical path, the optimal population density and cell-growth inhibition.

PubMed

Richmond, Amos; Cheng-Wu, Zhang; Zarmi, Yair

2003-07-01

The interrelationships between the optical path in flat plate reactors and photosynthetic productivity were elucidated. In preliminary works, a great surge in photosynthetic productivity was attained in flat plate photoreactors with an ultra short (e.g. 1.0 cm) optical path, in which extremely high culture density was facilitated by vigorous stirring and strong light. This surge in net photosynthetic efficiency was associated with a very significant increase in the optimal population density facilitated by the very short optical path (OP). A salient feature of these findings concerns the necessity to address growth inhibition (GI) which becomes increasingly manifested as cell concentration rises above a certain, species-specific, threshold (e.g. 1-2 billion cells of Nannochloropsis sp. ml(-1)). Indeed, ultrahigh cell density cultures may be established and sustained only if growth inhibition is continuously, or at least frequently, removed. Nannochloropsis culture from which GI was not removed, yielded 60 mg(-1) h(-1), yielding 260 mg l(-1) h(-1) when GI was removed. Two basic factors crucial for obtaining maximal photosynthetic productivity and efficiency in strong photon irradiance are defined: (1) areal cell density must be optimal, as high as possible (cell growth inhibition having been eliminated), insuring the average photon irradiance (I(av)) available per cell is falling at the end of the linear phase of the PI(av) curve, relating rate of photosynthesis to I(av), i.e. approximately photon irradiance per cell. (2) The light-dark (L-D) cycle period, which is determined by travel time of cells between the dark and the light volumes along the optical path, should be made as short as practically feasible, so as to approach, as much as possible the photosynthetic unit turnover time. This is obtainable in flat plate reactors by reducing the OP to as small a magnitude as is practically feasible.

Influence of operating conditions on the optimum design of electric vehicle battery cooling plates

NASA Astrophysics Data System (ADS)

Jarrett, Anthony; Kim, Il Yong

2014-01-01

The efficiency of cooling plates for electric vehicle batteries can be improved by optimizing the geometry of internal fluid channels. In practical operation, a cooling plate is exposed to a range of operating conditions dictated by the battery, environment, and driving behaviour. To formulate an efficient cooling plate design process, the optimum design sensitivity with respect to each boundary condition is desired. This determines which operating conditions must be represented in the design process, and therefore the complexity of designing for multiple operating conditions. The objective of this study is to determine the influence of different operating conditions on the optimum cooling plate design. Three important performance measures were considered: temperature uniformity, mean temperature, and pressure drop. It was found that of these three, temperature uniformity was most sensitive to the operating conditions, especially with respect to the distribution of the input heat flux, and also to the coolant flow rate. An additional focus of the study was the distribution of heat generated by the battery cell: while it is easier to assume that heat is generated uniformly, by using an accurate distribution for design optimization, this study found that cooling plate performance could be significantly improved.

Extreme ultraviolet quantum efficiency of opaque alkali halide photocathodes on microchannel plates

NASA Technical Reports Server (NTRS)

Siegmund, O. H. W.; Everman, E.; Vallerga, J. V.; Lampton, M.

1988-01-01

Comprehensive measurements are presented for the quantum detection efficiency (QDE) of the microchannel plate materials CsI, KBr, KCl, and MgF2, over the 44-1800 A wavelength range. QDEs in excess of 40 percent are achieved by several materials in specific wavelength regions of the EUV. Structure is noted in the wavelength dependence of the QDE that is directly related to the valence-band/conduction-band gap energy and the onset of atomic-like resonant transitions. A simple photocathode model allows interpretation of these features, together with the QDE efficiency variation, as a function of illumination angle.

Do Cues Matter? Highly Inductive Settlement Cues Don't Ensure High Post-Settlement Survival in Sea Urchin Aquaculture

PubMed Central

Mos, Benjamin; Cowden, Kenneth L.; Nielsen, Shaun J.; Dworjanyn, Symon A.

2011-01-01

Increasing settlement and post-settlement survival during the critical transition from planktonic larvae to benthic juveniles will increase efficiency for sea urchin aquaculture. This study investigated the effects of temperature and settlement cues on the settlement and post-settlement survival of the sea urchin Tripneustes gratilla during this phase. The current commercial methodology, which utilises natural biofilm settlement plates, was tested and resulted in low settlement (<2%) and poor post-settlement survival (<1% of settled urchins). In laboratory trials, settlement was high and unaffected by temperatures between 24 and 30°C, but significantly decreased at 33°C. Development of spines, however, was significantly affected by temperatures over 29°C. Mirroring this result, post-settlement survival was optimal between 24–28°C. In laboratory assays, the macroalgae Sargassum linearifolium and Corallina officinalis, and seawater conditioned with these algae, induced significantly higher settlement (>90%) than a natural biofilm (∼25%). The addition of macroalgae-conditioned seawater to natural biofilm significantly increased settlement rates (>85%). Mixed consortia and single strains of bacteria isolated from macroalgae, biofilms and adult conspecifics all induced significant settlement, but at significantly lower rates than macroalgae. No evidence was found that higher rates of settlement to bacteria on macroalgae were generated by a cofactor from the macroalgae. Age of bacterial cultures, culturing bacteria on solid and liquid media and concentration of nutrients in cultures had little effect on settlement rates. Finally, macroalgae-conditioned seawater combined with natural biofilm settlement plates induced significantly higher settlement than to the biofilm plates alone in a commercial scale trial. However, high post-settlement mortality resulted in equivalent survival between treatments after 25 days. This study highlights that settlement studies should extend to post-settlement survival, which remains poor for T. gratilla and is a significant obstacle to increasing efficiency for aquaculture. PMID:22162755

Carbon black dispersion pre-plating technology for printed wire board manufacturing. Final technology evaluation report

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

Folsom, D.W.; Gavaskar, A.R.; Jones, J.A.

1993-10-01

The project compared chemical use, waste generation, cost, and product quality between electroless copper and carbon-black-based preplating technologies at the printed wire board (PWB) manufacturing facility of McCurdy Circuits in Orange, CA. The carbon-black based preplating technology evaluated is used as an alternative process for electroless copper (EC) plating of through-holes before electrolytic copper plating. The specific process used at McCurdy is the BlackHole (BH) technology process, which uses a dispersion of carbon black in an aqueous solution to provide a conductive surface for subsequent electrolytic copper plating. The carbon-black dispersion technology provided effective waste reduction and long-term cost savings.more » The economic analysis determined that the new process was cost efficient because chemical use was reduced and the process proved more efficient; the payback period was less than 4 yrs.« less

Enhanced production of electron cyclotron resonance plasma by exciting selective microwave mode on a large-bore electron cyclotron resonance ion source with permanent magnet.

PubMed

Kimura, Daiju; Kurisu, Yosuke; Nozaki, Dai; Yano, Keisuke; Imai, Youta; Kumakura, Sho; Sato, Fuminobu; Kato, Yushi; Iida, Toshiyuki

2014-02-01

We are constructing a tandem type ECRIS. The first stage is large-bore with cylindrically comb-shaped magnet. We optimize the ion beam current and ion saturation current by a mobile plate tuner. They change by the position of the plate tuner for 2.45 GHz, 11-13 GHz, and multi-frequencies. The peak positions of them are close to the position where the microwave mode forms standing wave between the plate tuner and the extractor. The absorbed powers are estimated for each mode. We show a new guiding principle, which the number of efficient microwave mode should be selected to fit to that of multipole of the comb-shaped magnets. We obtained the excitation of the selective modes using new mobile plate tuner to enhance ECR efficiency.

On plate graphite supported sample processing for simultaneous lipid and protein identification by matrix assisted laser desorption ionization mass spectrometry.

PubMed

Calvano, Cosima Damiana; van der Werf, Inez Dorothé; Sabbatini, Luigia; Palmisano, Francesco

2015-05-01

The simultaneous identification of lipids and proteins by matrix assisted laser desorption ionization-mass spectrometry (MALDI-MS) after direct on-plate processing of micro-samples supported on colloidal graphite is demonstrated. Taking advantages of large surface area and thermal conductivity, graphite provided an ideal substrate for on-plate proteolysis and lipid extraction. Indeed proteins could be efficiently digested on-plate within 15 min, providing sequence coverages comparable to those obtained by conventional in-solution overnight digestion. Interestingly, detection of hydrophilic phosphorylated peptides could be easily achieved without any further enrichment step. Furthermore, lipids could be simultaneously extracted/identified without any additional treatment/processing step as demonstrated for model complex samples such as milk and egg. The present approach is simple, efficient, of large applicability and offers great promise for protein and lipid identification in very small samples. Copyright © 2015 Elsevier B.V. All rights reserved.

Heat Transfer and Friction Characteristics of Artificially Roughened Duct used for Solar Air Heaters—a Review

NASA Astrophysics Data System (ADS)

Kumar, Khushmeet; Prajapati, D. R.; Samir, Sushant

2018-02-01

Solar air heater uses the energy coming from the sun to heat the air. The conversion rate of solar energy to heat depends upon the efficiency of the solar air heater and this efficiency can be increased by the use of artificial roughness on the surface of absorber plate. Various studies were carried out to analyse the effect of different roughness geometries on heat transfer and friction factor characteristics. The thermo-hydraulic performance of solar air heater can be evaluated in terms of effective efficiency, thermo-hydraulic performance parameter and exergetic efficiency. In this study various geometries used for artificial roughness and to improve the performance of solar air heaters were studied. Also correlations developed by various researchers are presented in this paper.

Passive margins getting squeezed in the mantle convection vice

NASA Astrophysics Data System (ADS)

Husson, Laurent; Yamato, Philippe; Becker, Thorsten; Pedoja, Kevin

2013-04-01

Quaternary coastal geomorphology reveals that passive margins underwent wholesale uplift at least during the glacial cycle. In addition, these not-so-passive margins often exhibit long term exhumation and tectonic inversion, which suggest that compression and tectonic shortening could be the mechanism that triggers their overall uplift. We speculate that the compression in the lithosphere gradually increased during the Cenozoic. The many mountain belts at active margins that accompany this event readily witness this increase. Less clear is how that compression increase affects passive margins. In order to address this issue, we design minimalist 2D viscous models to quantify the impact of plate collision on the stress regime. In these models, a sluggish plate is disposed on a less viscous mantle. It is driven by a "mantle conveyor belt" alternatively excited by lateral shear stresses that represent a downwelling on one side, an upwelling on the other side, or both simultaneously. The lateral edges of the plate are either free or fixed, respectively representing the cases of free convergence and collision. In practice, it dramatically changes the upper boundary condition for mantle circulation and subsequently, for the stress field. The flow pattern transiently evolves almost between two end-members, starting from a situation close to a Couette flow to a pattern that looks like a Poiseuille flow with an almost null velocity at the surface (though in the models, the horizontal velocity at the surface is not strictly null, as the lithosphere deforms). In the second case, the lithosphere is highly stressed horizontally and deforms. For an equivalent bulk driving force, compression increases drastically at passive margins if upwellings are active because they push plates towards the collision. Conversely, if only downwellings are activated, compression occurs on one half of the plate and extension on the other half, because only the downwelling is pulling the plate. Thus, active upwellings underneath oceanic plates are required to explain compression at passive margins. This conclusion is corroborated by "real-Earth" 3D spherical models, wherein the flow is alternatively driven by density anomalies inferred from seismic tomography -and therefore include both downwellings at subduction zones and upwellings above the superswells- and density anomalies that correspond to subducting slabs only. While the second scenario mostly compresses the active margins of upper plates and leave other areas at rest, the first scenario efficiently compresses passive margins where the geological record reveals their uplift, exhumation, and tectonic inversion.

High power single-longitudinal-mode Ho:YLF unidirectional ring laser based on a composite structure of acousto-optic device and wave plate

NASA Astrophysics Data System (ADS)

Dai, T. Y.; Fan, Z. G.; Wu, J.; Ju, Y. L.; Yao, B. Q.; Zhang, Z. G.; Teng, K.; Xu, X. G.; Duan, X. M.

2017-05-01

We report a unidirectional single-longitudinal-mode Ho:YLF ring laser. An acousto-optic modulator and two half-wave plates were used to enforce the Ho:YLF ring laser in a unidirectional operation. The single-longitudinal-mode output power could reach 3.73 W successfully when the incident pump power was 16.4 W. The corresponding slope efficiency was 27.1%. The wavelength of the single-longitudinal-mode Ho:YLF ring laser was 2063.8 nm. The M2 factor was 1.12. The results illustrated that the single-longitudinal-mode output power could be further enhanced by increasing the radio frequency power of the acousto-optic modulator.

Stripping of acetone from water with microfabricated and membrane gas-liquid contactors.

PubMed

Constantinou, Achilleas; Ghiotto, Francesco; Lam, Koon Fung; Gavriilidis, Asterios

2014-01-07

Stripping of acetone from water utilizing nitrogen as a sweeping gas in co-current flow was conducted in a microfabricated glass/silicon gas-liquid contactor. The chip consisted of a microchannel divided into a gas and a liquid chamber by 10 μm diameter micropillars located next to one of the channel walls. The channel length was 35 mm, the channel width was 220 μm and the microchannel depth 100 μm. The micropillars were wetted by the water/acetone solution and formed a 15 μm liquid film between them and the nearest channel wall, leaving a 195 μm gap for gas flow. In addition, acetone stripping was performed in a microchannel membrane contactor, utilizing a hydrophobic PTFE membrane placed between two microstructured acrylic plates. Microchannels for gas and liquid flows were machined in the plates and had a depth of 850 μm and 200 μm respectively. In both contactors the gas/liquid interface was stabilized: in the glass/silicon contactor by the hydrophilic micropillars, while in the PTFE/acrylic one by the hydrophobic membrane. For both contactors separation efficiency was found to increase by increasing the gas/liquid flow rate ratio, but was not affected when increasing the inlet acetone concentration. Separation was more efficient in the microfabricated contactor due to the very thin liquid layer employed.

Protocols and programs for high-throughput growth and aging phenotyping in yeast.

PubMed

Jung, Paul P; Christian, Nils; Kay, Daniel P; Skupin, Alexander; Linster, Carole L

2015-01-01

In microorganisms, and more particularly in yeasts, a standard phenotyping approach consists in the analysis of fitness by growth rate determination in different conditions. One growth assay that combines high throughput with high resolution involves the generation of growth curves from 96-well plate microcultivations in thermostated and shaking plate readers. To push the throughput of this method to the next level, we have adapted it in this study to the use of 384-well plates. The values of the extracted growth parameters (lag time, doubling time and yield of biomass) correlated well between experiments carried out in 384-well plates as compared to 96-well plates or batch cultures, validating the higher-throughput approach for phenotypic screens. The method is not restricted to the use of the budding yeast Saccharomyces cerevisiae, as shown by consistent results for other species selected from the Hemiascomycete class. Furthermore, we used the 384-well plate microcultivations to develop and validate a higher-throughput assay for yeast Chronological Life Span (CLS), a parameter that is still commonly determined by a cumbersome method based on counting "Colony Forming Units". To accelerate analysis of the large datasets generated by the described growth and aging assays, we developed the freely available software tools GATHODE and CATHODE. These tools allow for semi-automatic determination of growth parameters and CLS behavior from typical plate reader output files. The described protocols and programs will increase the time- and cost-efficiency of a number of yeast-based systems genetics experiments as well as various types of screens.

Attenuation characteristics of fiberoptic plates for digital mammography and other X-ray imaging applications.

PubMed

Vedantham, S; Karellas, A; Suryanarayanan, S

2003-01-01

Spatially coherent fiberoptic plates are important components of some charge-coupled device (CCD)-based x-ray imaging systems. These plates efficiently transmit scintillations from the phosphor, and also filter out x-rays not absorbed by the phosphor, thus protecting the CCD from direct x-ray interaction. The thickness of the fiberoptic plate and the CCD package present a significant challenge in the design of a digital x-ray cassette capable of insertion into the existing film-screen cassette holders of digital mammography systems. This study was performed with an aim to optimize fiberoptic plate thickness. Attenuation measurements were performed on nine fiberoptic plates varying in material composition that exhibit desirable optical characteristics such as good coupling efficiency. Mammographic spectra from a clinical mammographic system and an Americium-241 (Am-241) source (59.54 KeV) were used. The spectra were recorded with a high-resolution cadmium zinc telluride (CZT)-based spectrometer and corrected for dead time and pile-up. The linear attenuation coefficients varied by a factor of 3 in the set of tested fiberoptic plates at both mammographic energies and 59.54 keV. Our results suggest that a 3-mm thick high-absorption plate might provide adequate for shielding at mammographic energies. A thickness of 2-mm is feasible for mammographic applications with further optimization of the fiberoptic plate composition by incorporating non-scintillating, high-atomic number material. This would allow more space for cooling components of the cassette and for a more compact device, which is critical for clinical implementation of the technology.

The hydrodynamic principle for the caudal fin shape of small aquatic animals

NASA Astrophysics Data System (ADS)

Lee, Jeongsu; Park, Yong-Jai; Cho, Kyu-Jin; Kim, Ho-Young

2014-11-01

The shape of caudal fins of small aquatic animals is completely different from that of large cruising animals like dolphin and tuna which have high aspect-ratio lunate tail. To unveil the physical principle behind natural selection of caudal fins of small aquatic animals, here we investigate the hydrodynamics of an angularly reciprocating plate as a model for the caudal fin oscillation. We find that the thrust production of a reciprocating plate at high Strouhal numbers is dominated by generation of two distinct vortical structures associated with the acceleration and deceleration of the plate regardless of their shape. Based on our observations, we construct a scaling law to predict the thrust of the flapping plate, which agrees well with the experimental data. We then seek the optimal aspect ratio to maximize thrust and efficiency of a flapping plate for fixed flapping frequency and amplitude. Thrust is maximized for the aspect ratio of approximately 0.7. We also theoretically explain the power law behaviors of the thrust and efficiency as a function of the aspect ratio.

A model for the Global Quantum Efficiency for a TPB-based wavelength-shifting system used with photomultiplier tubes in liquid argon in MicroBooNE

DOE PAGES

Pate, S. F.; Wester, T.; Bugel, L.; ...

2018-02-28

We present a model for the Global Quantum Efficiency (GQE) of the MicroBooNE optical units. An optical unit consists of a flat, circular acrylic plate, coated with tetraphenyl butadiene (TPB), positioned near the photocathode of a 20.2-cm diameter photomultiplier tube. The plate converts the ultra-violet scintillation photons from liquid argon into visible-spectrum photons to which the cryogenic phototubes are sensitive. The GQE is the convolution of the efficiency of the plates that convert the 128 nm scintillation light from liquid argon to visible light, the efficiency of the shifted light to reach the photocathode, and the efficiency of the cryogenic photomultiplier tube. We develop a GEANT4-based model of the optical unit, based on first principles, and obtain the range of probable values for the expected number of detected photoelectrons (more » $$N_{\\rm PE}$$) given the known systematic errors on the simulation parameters. We compare results from four measurements of the $$N_{\\rm PE}$$ determined using alpha-particle sources placed at two distances from a TPB-coated plate in a liquid argon cryostat test stand. We also directly measured the radial dependence of the quantum efficiency, and find that this has the same shape as predicted by our model. Our model results in a GQE of $$0.0055\\pm0.0009$$ for the MicroBooNE optical units. While the information shown here is MicroBooNE specific, the approach to the model and the collection of simulation parameters will be widely applicable to many liquid-argon-based light collection systems.« less

A model for the Global Quantum Efficiency for a TPB-based wavelength-shifting system used with photomultiplier tubes in liquid argon in MicroBooNE

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

Pate, S. F.; Wester, T.; Bugel, L.

We present a model for the Global Quantum Efficiency (GQE) of the MicroBooNE optical units. An optical unit consists of a flat, circular acrylic plate, coated with tetraphenyl butadiene (TPB), positioned near the photocathode of a 20.2-cm diameter photomultiplier tube. The plate converts the ultra-violet scintillation photons from liquid argon into visible-spectrum photons to which the cryogenic phototubes are sensitive. The GQE is the convolution of the efficiency of the plates that convert the 128 nm scintillation light from liquid argon to visible light, the efficiency of the shifted light to reach the photocathode, and the efficiency of the cryogenic photomultiplier tube. We develop a GEANT4-based model of the optical unit, based on first principles, and obtain the range of probable values for the expected number of detected photoelectrons (more » $$N_{\\rm PE}$$) given the known systematic errors on the simulation parameters. We compare results from four measurements of the $$N_{\\rm PE}$$ determined using alpha-particle sources placed at two distances from a TPB-coated plate in a liquid argon cryostat test stand. We also directly measured the radial dependence of the quantum efficiency, and find that this has the same shape as predicted by our model. Our model results in a GQE of $$0.0055\\pm0.0009$$ for the MicroBooNE optical units. While the information shown here is MicroBooNE specific, the approach to the model and the collection of simulation parameters will be widely applicable to many liquid-argon-based light collection systems.« less

Microchannel Plate Imaging Detectors for the Ultraviolet

NASA Technical Reports Server (NTRS)

Siegmund, O. H. W.; Gummin, M. A.; Stock, J.; Marsh, D.

1992-01-01

There has been significant progress over the last few years in the development of technologies for microchannel plate imaging detectors in the Ultraviolet (UV). Areas where significant developments have occurred include enhancements of quantum detection efficiency through improved photocathodes, advances in microchannel plate performance characteristics, and development of high performance image readout techniques. The current developments in these areas are summarized, with their applications in astrophysical instrumentation.

Asymptotic modal analysis of a rectangular acoustic cavity excited by wall vibration

NASA Technical Reports Server (NTRS)

Peretti, Linda F.; Dowell, Earl H.

1992-01-01

Asymptotic modal analysis, a method that has recently been developed for structural dynamical systems, has been applied to a rectangular acoustic cavity. The cavity had a flexible vibrating portion on one wall, and the other five walls were rigid. Banded white noise was transmitted through the flexible portion (plate) only. Both the location along the wall and the size of the plate were varied. The mean square pressure levels of the cavity interior were computed as a ratio of the result obtained from classical modal analysis to that obtained from asymptotic modal analysis for the various plate configurations. In general, this ratio converged to 1.0 as the number of responding modes increased. Intensification effects were found due to both the excitation location and the response location. The asymptotic modal analysis method was both efficient and accurate in solving the given problem. The method has advantages over the traditional methods that are used for solving dynamics problems with a large number of responding modes.

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.

Strength and Deformation Rate of Plate Boundaries: The Rheological Effects of Grain Size Reduction, Structure, and Serpentinization.

NASA Astrophysics Data System (ADS)

Montesi, L.; Gueydan, F.

2016-12-01

Global strain rate maps reveal 1000-fold contrasts between plate interiors, oceanic or continental diffuse plate boundaries and narrow plate boundaries. Here, we show that rheological models based on the concepts of shear zone localization and the evolution of rock structure upon strain can explain these strain rate contrasts. Ductile shear zones constitute a mechanical paradox in the lithosphere. As every plastic deformation mechanism is strain-rate-hardening, ductile rocks are expected to deform at low strain rate and low stress (broad zone of deformation). Localized ductile shear zones require either a localized forcing (locally high stress) or a thermal or structural anomaly in the shear zone; either can be inherited or develop progressively as rocks deform. We previously identified the most effective process at each depth level of the lithosphere. In the upper crust and middle crust, rocks fabric controls localization. Grain size reduction is the most efficient mechanism in the uppermost mantle. This analysis can be generalized to consider a complete lithospheric section. We assume strain rate does not vary with depth and that the depth-integrated strength of the lithospheric does not change over time, as the total force is controlled by external process such as mantle convection and plate and slab buoyancy. Reducing grain size from a coarse value typical of undeformed peridotite to a value in agreement with the stress level (piezometer) while letting that stress vary from depth to depth (the integrated stress remains the same) increases the lithospheric strain rate by about a factor of 1000. This can explain the development of diffuse plate boundaries. The slightly higher strain rate of continental plate boundary may reflect development of a layered rock fabric in the middle crust. Narrow plate boundaries require additional weakening process. The high heat flux near mid-ocean ridge implies a thin lithosphere, which enhances stress (for constant integrated stress). While this can increase strain rate by another factor of 1000, another process must generate the lithospheric thickness variation in the first place. One possibility is serpentinization, which reduces the strength of the brittle crust, especially when coupled with the development of a fabric in brittle faults.

An interlaboratory study on efficient detection of Shiga toxin-producing Escherichia coli O26, O103, O111, O121, O145, and O157 in food using real-time PCR assay and chromogenic agar.

PubMed

Hara-Kudo, Yukiko; Konishi, Noriko; Ohtsuka, Kayoko; Iwabuchi, Kaori; Kikuchi, Rie; Isobe, Junko; Yamazaki, Takumiko; Suzuki, Fumie; Nagai, Yuhki; Yamada, Hiroko; Tanouchi, Atsuko; Mori, Tetsuya; Nakagawa, Hiroshi; Ueda, Yasufumi; Terajima, Jun

2016-08-02

To establish an efficient detection method for Shiga toxin (Stx)-producing Escherichia coli (STEC) O26, O103, O111, O121, O145, and O157 in food, an interlaboratory study using all the serogroups of detection targets was firstly conducted. We employed a series of tests including enrichment, real-time PCR assays, and concentration by immunomagnetic separation, followed by plating onto selective agar media (IMS-plating methods). This study was particularly focused on the efficiencies of real-time PCR assays in detecting stx and O-antigen genes of the six serogroups and of IMS-plating methods onto selective agar media including chromogenic agar. Ground beef and radish sprouts samples were inoculated with the six STEC serogroups either at 4-6CFU/25g (low levels) or at 22-29CFU/25g (high levels). The sensitivity of stx detection in ground beef at both levels of inoculation with all six STEC serogroups was 100%. The sensitivity of stx detection was also 100% in radish sprouts at high levels of inoculation with all six STEC serogroups, and 66.7%-91.7% at low levels of inoculation. The sensitivity of detection of O-antigen genes was 100% in both ground beef and radish sprouts at high inoculation levels, while at low inoculation levels, it was 95.8%-100% in ground beef and 66.7%-91.7% in radish sprouts. The sensitivity of detection with IMS-plating was either the same or lower than those of the real-time PCR assays targeting stx and O-antigen genes. The relationship between the results of IMS-plating methods and Ct values of real-time PCR assays were firstly analyzed in detail. Ct values in most samples that tested negative in the IMS-plating method were higher than the maximum Ct values in samples that tested positive in the IMS-plating method. This study indicates that all six STEC serogroups in food contaminated with more than 29CFU/25g were detected by real-time PCR assays targeting stx and O-antigen genes and IMS-plating onto selective agar media. Therefore, screening of stx and O-antigen genes followed by isolation of STECs by IMS-plating methods may be an efficient method to detect the six STEC serogroups. Copyright © 2016 Elsevier B.V. All rights reserved.

High-throughput process development: determination of dynamic binding capacity using microtiter filter plates filled with chromatography resin.

PubMed

Bergander, Tryggve; Nilsson-Välimaa, Kristina; Oberg, Katarina; Lacki, Karol M

2008-01-01

Steadily increasing demand for more efficient and more affordable biomolecule-based therapies put a significant burden on biopharma companies to reduce the cost of R&D activities associated with introduction of a new drug to the market. Reducing the time required to develop a purification process would be one option to address the high cost issue. The reduction in time can be accomplished if more efficient methods/tools are available for process development work, including high-throughput techniques. This paper addresses the transitions from traditional column-based process development to a modern high-throughput approach utilizing microtiter filter plates filled with a well-defined volume of chromatography resin. The approach is based on implementing the well-known batch uptake principle into microtiter plate geometry. Two variants of the proposed approach, allowing for either qualitative or quantitative estimation of dynamic binding capacity as a function of residence time, are described. Examples of quantitative estimation of dynamic binding capacities of human polyclonal IgG on MabSelect SuRe and of qualitative estimation of dynamic binding capacity of amyloglucosidase on a prototype of Capto DEAE weak ion exchanger are given. The proposed high-throughput method for determination of dynamic binding capacity significantly reduces time and sample consumption as compared to a traditional method utilizing packed chromatography columns without sacrificing the accuracy of data obtained.

Geometrically nonlinear resonance of higher-order shear deformable functionally graded carbon-nanotube-reinforced composite annular sector plates excited by harmonic transverse loading

NASA Astrophysics Data System (ADS)

Gholami, Raheb; Ansari, Reza

2018-02-01

This article presents an attempt to study the nonlinear resonance of functionally graded carbon-nanotube-reinforced composite (FG-CNTRC) annular sector plates excited by a uniformly distributed harmonic transverse load. To this purpose, first, the extended rule of mixture including the efficiency parameters is employed to approximately obtain the effective material properties of FG-CNTRC annular sector plates. Then, the focus is on presenting the weak form of discretized mathematical formulation of governing equations based on the variational differential quadrature (VDQ) method and Hamilton's principle. The geometric nonlinearity and shear deformation effects are considered based on the von Kármán assumptions and Reddy's third-order shear deformation plate theory, respectively. The discretization process is performed via the generalized differential quadrature (GDQ) method together with numerical differential and integral operators. Then, an efficient multi-step numerical scheme is used to obtain the nonlinear dynamic behavior of the FG-CNTRC annular sector plates near their primary resonance as the frequency-response curve. The accuracy of the present results is first verified and then a parametric study is presented to show the impacts of CNT volume fraction, CNT distribution pattern, geometry of annular sector plate and sector angle on the nonlinear frequency-response curve of FG-CNTRC annular sector plates with different edge supports.

Study on an undershot cross-flow water turbine

NASA Astrophysics Data System (ADS)

Nishi, Yasuyuki; Inagaki, Terumi; Li, Yanrong; Omiya, Ryota; Fukutomi, Junichiro

2014-06-01

This study aims to develop a water turbine suitable for ultra-low heads in open channels, with the end goal being the effective utilization of unutilized hydroelectric energy in agricultural water channels. We performed tests by applying a cross-flow runner to an open channel as an undershot water turbine while attempting to simplify the structure and eliminate the casing. We experimentally investigated the flow fields and performance of water turbines in states where the flow rate was constant for the undershot cross-flow water turbine mentioned above. In addition, we compared existing undershot water turbines with our undershot cross-flow water turbine after attaching a bottom plate to the runner. From the results, we were able to clarify the following. Although the effective head for cross-flow runners with no bottom plate was lower than those found in existing runners equipped with a bottom plate, the power output is greater in the high rotational speed range because of the high turbine efficiency. Also, the runner with no bottom plate differed from runners that had a bottom plate in that no water was being wound up by the blades or retained between the blades, and the former received twice the flow due to the flow-through effect. As a result, the turbine efficiency was greater for runners with no bottom plate in the full rotational speed range compared with that found in runners that had a bottom plate.

Experimental Observation of the Effects of Translational and Rotational Electrode Misalignment on a Planar Linear Ion Trap Mass Spectrometer

NASA Astrophysics Data System (ADS)

Tian, Yuan; Decker, Trevor K.; McClellan, Joshua S.; Wu, Qinghao; De la Cruz, Abraham; Hawkins, Aaron R.; Austin, Daniel E.

2018-04-01

The performance of miniaturized ion trap mass analyzers is limited, in part, by the accuracy with which electrodes can be fabricated and positioned relative to each other. Alignment of plates in a two-plate planar LIT is ideal to characterize misalignment effects, as it represents the simplest possible case, having only six degrees of freedom (DOF) (three translational and three rotational). High-precision motorized actuators were used to vary the alignment between the two ion trap plates in five DOFs—x, y, z, pitch, and yaw. A comparison between the experiment and previous simulations shows reasonable agreement. Pitch, or the degree to which the plates are parallel along the axial direction, has the largest and sharpest impact to resolving power, with resolving power dropping noticeably with pitch misalignment of a fraction of a degree. Lateral displacement (x) and yaw (rotation of one plate, but plates remain parallel) both have a strong impact on ion ejection efficiency, but little effect on resolving power. The effects of plate spacing (y-displacement) on both resolving power and ion ejection efficiency are attributable to higher-order terms in the trapping field. Varying the DC (axial) trapping potential can elucidate the effects where more misalignments in more than one DOF affect performance. Implications of these results for miniaturized ion traps are discussed. [Figure not available: see fulltext.

A thermo-mechanical model of horizontal subduction below an overriding plate

NASA Astrophysics Data System (ADS)

van Hunen, Jeroen; van den Berg, Arie P.; Vlaar, Nico J.

2000-10-01

Subduction of young oceanic lithosphere cannot be explained by the gravitational driving mechanisms of slab pull and ridge push. This deficiency of driving forces can be overcome by obduction of an actively overriding plate, which forces the young plate either to subduct or to collide. This mechanism leads to shallow flattening of the slab as observed today under parts of the west coast of North and South America. Here this process is examined by means of numerical modeling. The convergence velocity between oceanic and continental lithospheric plates is computed from the modeling results, and the ratio of the subduction velocity over the overriding velocity is used as a diagnostic of the efficiency of the ongoing subduction process. We have investigated several factors influencing the mechanical resistance working against the subduction process. In particular, we have studied the effect of a preexisting lithospheric fault with a depth dependent shear resistance, partly decoupling the oceanic lithosphere from the overriding continent. We also investigated the lubricating effect of a 7 km thick basaltic crustal layer on the efficiency of the subduction process and found a log-linear relation between convergence rate and viscosity prefactor characterizing the strength of the oceanic crust, for a range of parameter values including values for basaltic rocks, derived from empirical data. A strong mantle fixes the subducting slab while being overridden and prevents the slab from further subduction in a Benioff style. Viscous heating lowers the coupling strength of the crustal interface between the converging plates with about half an order of magnitude and therefore contributes significantly to the subduction process. Finally, when varying the overriding velocity from 2.5 to 10 cm yr -1, we found a non-linear increase of the subduction velocity due to the presence of non-linear mantle rheology. These results indicate that active obduction of oceanic lithosphere by an overriding continental lithosphere is a viable mechanism for shallow flat subduction over a wide range of model parameters.

The Thermal Collector With Varied Glass Covers

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

Luminosu, I.; Pop, N.

2010-08-04

The thermal collector with varied glass covers represents an innovation realized in order to build a collector able to reach the desired temperature by collecting the solar radiation from the smallest surface, with the highest efficiency. In the case of the thermal collector with variable cover glasses, the number of the glass plates covering the absorber increases together with the length of the circulation pipe for the working fluid. The thermal collector with varied glass covers compared to the conventional collector better meet user requirements because: for the same temperature increase, has the collecting area smaller; for the same collectionmore » area, realizes the highest temperature increase and has the highest efficiency. This works is addressed to researchers in the solar energy and to engineers responsible with air-conditioning systems design or industrial and agricultural products drying.« less

Invited article: Broadband highly-efficient dielectric metadevices for polarization control

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

Kruk, Sergey; Hopkins, Ben; Kravchenko, Ivan I.

Metadevices based on dielectric nanostructured surfaces with both electric and magnetic Mie-type resonances have resulted in the best efficiency to date for functional flat optics with only one disadvantage: a narrow operational bandwidth. Here we experimentally demonstrate broadband transparent all-dielectric metasurfaces for highly efficient polarization manipulation. We utilize the generalized Huygens principle, with a superposition of the scattering contributions from several electric and magnetic multipolar modes of the constituent meta-atoms, to achieve destructive interference in reflection over a large spectral bandwidth. Furthermore, by employing this novel concept, we demonstrate reflectionless (~90% transmission) half-wave plates, quarter-wave plates, and vector beam q-platesmore » that can operate across multiple telecom bands with ~99% polarization conversion efficiency.« less

Invited article: Broadband highly-efficient dielectric metadevices for polarization control

DOE PAGES

Kruk, Sergey; Hopkins, Ben; Kravchenko, Ivan I.; ...

2016-06-06

Metadevices based on dielectric nanostructured surfaces with both electric and magnetic Mie-type resonances have resulted in the best efficiency to date for functional flat optics with only one disadvantage: a narrow operational bandwidth. Here we experimentally demonstrate broadband transparent all-dielectric metasurfaces for highly efficient polarization manipulation. We utilize the generalized Huygens principle, with a superposition of the scattering contributions from several electric and magnetic multipolar modes of the constituent meta-atoms, to achieve destructive interference in reflection over a large spectral bandwidth. Furthermore, by employing this novel concept, we demonstrate reflectionless (~90% transmission) half-wave plates, quarter-wave plates, and vector beam q-platesmore » that can operate across multiple telecom bands with ~99% polarization conversion efficiency.« less

Neutronic and thermal-hydraulic analysis of fission molybdenum-99 production at Tehran Research Reactor using LEU plate targets.

PubMed

Abedi, Ebrahim; Ebrahimkhani, Marzieh; Davari, Amin; Mirvakili, Seyed Mohammad; Tabasi, Mohsen; Maragheh, Mohammad Ghannadi

2016-12-01

Efficient and safe production of molybdenum-99 ( 99 Mo) radiopharmaceutical at Tehran Research Reactor (TRR) via fission of LEU targets is studied. Neutronic calculations are performed to evaluate produced 99 Mo activity, core neutronic safety parameters and also the power deposition values in target plates during a 7 days irradiation interval. Thermal-hydraulic analysis has been also carried out to obtain thermal behavior of these plates. Using Thermal-hydraulic analysis, it can be concluded that the safety parameters are satisfied in the current study. Consequently, the present neutronic and thermal-hydraulic calculations show efficient 99 Mo production is accessible at significant activity values in TRR current core configuration. Copyright © 2016 Elsevier Ltd. All rights reserved.

JPRS Report, Science & Technology, USSR: Engineering & Equipment

DTIC Science & Technology

1989-01-30

flux density and of the speed and density of the mass flux, have a long operating life , and are economical. A technology has been developed for...water pro- vides a repair-free service life of 20 to 30 years. JPRS-ueq-89-002 30 January 1989 Industrial Technology, Planning, Productivity...to raise the temperature of the working body, increase its efficiency, and reduce fuel consumption. Ceramic cutting plates permit a two- to

MALDI TOF Imaging of Latent Fingerprints a Novel Biosignature Tool

DTIC Science & Technology

2010-04-23

old man have been lightly coated with ointment containing tocopherol and imprinted on stainless-steal MALDI plate. Application of low-concentrated... tocopherol allows efficient laser ionization without use of matrixes or additional treatment of the fingerprint. The result of the MS imaging scan...resolution and contrast. Interestingly, MS method optimized for molecular peak and main fragments of tocopherol (395 m/z) gave signal increase of over

High-efficiency and flexible generation of vector vortex optical fields by a reflective phase-only spatial light modulator.

PubMed

Cai, Meng-Qiang; Wang, Zhou-Xiang; Liang, Juan; Wang, Yan-Kun; Gao, Xu-Zhen; Li, Yongnan; Tu, Chenghou; Wang, Hui-Tian

2017-08-01

The scheme for generating vector optical fields should have not only high efficiency but also flexibility for satisfying the requirements of various applications. However, in general, high efficiency and flexibility are not compatible. Here we present and experimentally demonstrate a solution to directly, flexibly, and efficiently generate vector vortex optical fields (VVOFs) with a reflective phase-only liquid crystal spatial light modulator (LC-SLM) based on optical birefringence of liquid crystal molecules. To generate the VVOFs, this approach needs in principle only a half-wave plate, an LC-SLM, and a quarter-wave plate. This approach has some advantages, including a simple experimental setup, good flexibility, and high efficiency, making the approach very promising in some applications when higher power is need. This approach has a generation efficiency of 44.0%, which is much higher than the 1.1% of the common path interferometric approach.

Terrestrial photovoltaic collector technology trends

NASA Technical Reports Server (NTRS)

Shimada, K.; Costogue, E.

1984-01-01

Following the path of space PV collector development in its early stages, terrestrial PV technologies based upon single-crystal silicon have matured rapidly. Currently, terrestrial PV cells with efficiencies approaching space cell efficiencies are being fabricated into modules at a fraction of the space PV module cost. New materials, including CuInSe2 and amorphous silicon, are being developed for lowering the cost, and multijunction materials for achieving higher efficiency. Large grid-interactive, tracking flat-plate power systems and concentrator PV systems totaling about 10 MW, are already in operation. Collector technology development both flat-plate and concentrator, will continue under an extensive government and private industry partnership.

Hand portable thin-layer chromatography system

DOEpatents

Haas, Jeffrey S.; Kelly, Fredrick R.; Bushman, John F.; Wiefel, Michael H.; Jensen, Wayne A.

2000-01-01

A hand portable, field-deployable thin-layer chromatography (TLC) unit and a hand portable, battery-operated unit for development, illumination, and data acquisition of the TLC plates contain many miniaturized features that permit a large number of samples to be processed efficiently. The TLC unit includes a solvent tank, a holder for TLC plates, and a variety of tool chambers for storing TLC plates, solvent, and pipettes. After processing in the TLC unit, a TLC plate is positioned in a collapsible illumination box, where the box and a CCD camera are optically aligned for optimal pixel resolution of the CCD images of the TLC plate. The TLC system includes an improved development chamber for chemical development of TLC plates that prevents solvent overflow.

Illumination box and camera system

DOEpatents

Haas, Jeffrey S.; Kelly, Fredrick R.; Bushman, John F.; Wiefel, Michael H.; Jensen, Wayne A.; Klunder, Gregory L.

2002-01-01

A hand portable, field-deployable thin-layer chromatography (TLC) unit and a hand portable, battery-operated unit for development, illumination, and data acquisition of the TLC plates contain many miniaturized features that permit a large number of samples to be processed efficiently. The TLC unit includes a solvent tank, a holder for TLC plates, and a variety of tool chambers for storing TLC plates, solvent, and pipettes. After processing in the TLC unit, a TLC plate is positioned in a collapsible illumination box, where the box and a CCD camera are optically aligned for optimal pixel resolution of the CCD images of the TLC plate. The TLC system includes an improved development chamber for chemical development of TLC plates that prevents solvent overflow.

Viscoelastic property identification from waveform reconstruction

NASA Astrophysics Data System (ADS)

Leymarie, N.; Aristégui, C.; Audoin, B.; Baste, S.

2002-05-01

An inverse method is proposed for the determination of the viscoelastic properties of material plates from the plane-wave transmitted acoustic field. Innovations lie in a two-step inversion scheme based on the well-known maximum-likelihood principle with an analytic signal formulation. In addition, establishing the analytical formulations of the plate transmission coefficient we implement an efficient and slightly noise-sensitive process suited to both very thin plates and strongly dispersive media.

Degradation of Acid Orange 7 Dye in Two Hybrid Plasma Discharge Reactors

NASA Astrophysics Data System (ADS)

Shen, Yongjun; Lei, Lecheng; Zhang, Xingwang; Ding, Jiandong

2014-11-01

To get an optimized pulsed electrical plasma discharge reactor and to increase the energy utilization efficiency in the removal of pollutants, two hybrid plasma discharge reactors were designed and optimized. The reactors were compared via the discharge characteristics, energy transfer efficiency, the yields of the active species and the energy utilization in dye wastewater degradation. The results showed that under the same AC input power, the characteristics of the discharge waveform of the point-to-plate reactor were better. Under the same AC input power, the two reactors both had almost the same peak voltage of 22 kV. The peak current of the point-to-plate reactor was 146 A, while that of the wire-to-cylinder reactor was only 48.8 A. The peak powers of the point-to-plate reactor and the wire-to-cylinder reactor were 1.38 MW and 1.01 MW, respectively. The energy per pulse of the point-to-plate reactor was 0.2221 J, which was about 29.4% higher than that of the wire-to-cylinder reactor (0.1716 J). To remove 50% Acid Orange 7 (AO7), the energy utilizations of the point-to-plate reactor and the wire-to-cylinder reactor were 1.02 × 10-9 mol/L and 0.61 × 10-9 mol/L, respectively. In the point-to-plate reactor, the concentration of hydrogen peroxide in pure water was 3.6 mmol/L after 40 min of discharge, which was higher than that of the wire-to-cylinder reactor (2.5 mmol/L). The concentration of liquid phase ozone in the point-to-plate reactor (5.7 × 10-2 mmol/L) was about 26.7% higher than that in the wire-to-cylinder reactor (4.5 × 10-2 mmol/L). The analysis results of the variance showed that the type of reactor and reaction time had significant impacts on the yields of the hydrogen peroxide and ozone. The main degradation intermediates of AO7 identified by gas chromatography and mass spectrometry (GCMS) were acetic acid, maleic anhydride, p-benzoquinone, phenol, benzoic acid, phthalic anhydride, coumarin and 2-naphthol. Proposed degradation pathways were elucidated in light of the analyzed degradation products.

Development efforts to improve curved-channel microchannel plates

NASA Technical Reports Server (NTRS)

Corbett, M. B.; Feller, W. B.; Laprade, B. N.; Cochran, R.; Bybee, R.; Danks, A.; Joseph, C.

1993-01-01

Curved-channel microchannel plate (C-plate) improvements resulting from an ongoing NASA STIS microchannel plate (MCP) development program are described. Performance limitations of previous C-plates led to a development program in support of the STIS MAMA UV photon counter, a second generation instrument on the Hubble Space Telescope. C-plate gain, quantum detection efficiency, dark noise, and imaging distortion, which are influenced by channel curvature non-uniformities, have all been improved through use of a new centrifuge fabrication technique. This technique will be described, along with efforts to improve older, more conventional shearing methods. Process optimization methods used to attain targeted C-plate performance goals will be briefly characterized. Newly developed diagnostic measurement techniques to study image distortion, gain uniformity, input bias angle, channel curvature, and ion feedback, will be described. Performance characteristics and initial test results of the improved C-plates will be reported. Future work and applications will also be discussed.

Fixture for assembling solar panels

NASA Technical Reports Server (NTRS)

Dillard, P. A.; Fritz, W. M.

1979-01-01

Vacuum fixture attaches array of silicon solar cells to mounting plate made of clear glass which holds and protects cells. Glass plate transmits, rather than absorbs, solar energy thus cooling cells for efficient operation. Device therefore reduces handling of cells and interconnecting conductors to one operation.

The effect of barrier layer conditions on the electrodeposition efficiency and magnetic properties of Fe nanowire arrays

NASA Astrophysics Data System (ADS)

Akhtarianfar, S. F.; Ramazani, A.; Almasi-Kashi, M.; Montazer, A. H.

2018-05-01

Fabrication of different nanostructures based on template-assisted methods has become conventional, due to their numerous potential applications. In this paper, Fe nanowire arrays (NWAs) were fabricated using a pulsed electrodeposition in porous anodic alumina (PAA) templates. The effect of alumina barrier layer conditions such as barrier layer temperature (BLT) and Cu pre-plating at the dendritic sections of pores on the electrodeposition efficiency (EE) and magnetic properties of Fe NWAs in two pH regimes (2.6 and 4.0) has been investigated. At pH 4.0, BLT was changed from 4 to 32 °C, leading to an EE of approximately 60% for BLT 24 °C. Moreover, to overcome the problem of low EE 2% at the pH of 2.6, Cu pre-plating was performed with deposition current densities of 25 and 35 mA/cm2. This procedure increased the EE up to about 40%, providing a promising approach to enhance the EE in the fabrication of Fe NWAs. Furthermore, a nearly constant trend of magnetic properties was observed for highly crystalline Fe NWs.

Effects of dexamethasone on C6 astrocytoma radiosensitivity

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

Lordo, C.D.; Stroude, E.C.; Del Maestro, R.F.

1989-05-01

Brain-tumor patients often undergo radiation therapy while receiving corticosteroids for the treatment of cerebral edema. Studies have demonstrated that dexamethasone is radioprotective in a number of cell lines. The C6 astrocytoma cell line is well established in vitro and is modulated by dexamethasone treatment. It has therefore been hypothesized that dexamethasone-treated C6 astrocytoma cells would be more resistant to radiation-induced damage. The present study was carried out to assess this hypothesis using both the in vitro C6 astrocytoma monolayer and three-dimensional multicellular spheroid models. Dexamethasone was inhibitory to the C6 astrocytoma cells in the monolayer preparation, increasing their doubling timemore » by 13%. In the spheroid cultures, dexamethasone treatment decreased the number of cells per spheroid by 46%. Dexamethasone did not affect the plating efficiency of either the cells from the monolayer experiment or those dissociated from spheroids, however, suggesting that the inhibitory effect was not tumoricidal. At a clinical concentration (1.94 x 10(-5) M), dexamethasone did not significantly influence plating efficiency of irradiated C6 astrocytoma cells in monolayer or three-dimensional spheroid cultures.« less

Long-Term Stability of Plate-Like Behavior Caused by Hydrous Mantle Convection and Water Absorption in the Deep Mantle

NASA Astrophysics Data System (ADS)

Nakagawa, Takashi; Iwamori, Hikaru

2017-10-01

We investigate the cycling of water (regassing, dehydration, and degassing) in mantle convection simulations as a function of the strength of the oceanic lithosphere and its influence on the evolution of mantle water content. We also consider pseudo-plastic yielding with a friction coefficient for simulating brittle behavior of the plates and the water-weakening effect of mantle materials. This model can generate long-term plate-like behavior as a consequence of the water-weakening effect of mantle minerals. This finding indicates that water cycling plays an essential role in generating tectonic plates. In vigorous plate motion, the mantle water content rapidly increases by up to approximately 4-5 ocean masses, which we define as the "burst" effect. A burst is related to the mantle temperature and water solubility in the mantle transition zone. When the mantle is efficiently cooled down, the mantle transition zone can store water transported by the subducted slabs that can pass through the "choke point" of water solubility. The onset of the burst effect is strongly dependent on the friction coefficient. The burst effect of the mantle water content could have significantly influenced the evolution of the surface water if the burst started early, in which case the Earth's surface cannot preserve the surface water over the age of the Earth.

Efficiency of plasma actuator ionization in shock wave modification in a rarefied supersonic flow over a flat plate

NASA Astrophysics Data System (ADS)

Joussot, Romain; Lago, Viviana; Parisse, Jean-Denis

2014-12-01

This paper describes experimental and numerical investigations focused on the shock wave modification, induced by a dc glow discharge, of a Mach 2 flow under rarefied regime. The model under investigation is a flat plate equipped with a plasma actuator composed of two electrodes. The glow discharge is generated by applying a negative potential to the upstream electrode, enabling the creation of a weakly ionized plasma. The natural flow (i.e. without the plasma) exhibits a thick laminar boundary layer and a shock wave with a hyperbolic shape. Images of the flow obtained with an ICCD camera revealed that the plasma discharge induces an increase in the shock wave angle. Thermal effects (volumetric, and at the surface) and plasma effects (ionization, and thermal non-equilibrium) are the most relevant processes explaining the observed modifications. The effect induced by the heating of the flat plate surface is studied experimentally by replacing the upstream electrode by a heating element, and numerically by modifying the thermal boundary condition of the model surface. The results show that for a similar temperature distribution over the plate surface, modifications induced by the heating element are lower than those produced by the plasma. This difference shows that other effects than purely thermal effects are involved with the plasma actuator. Measurements of the electron density with a Langmuir probe highlight the fact that the ionization degree plays an important role into the modification of the flow. The gas properties, especially the isentropic exponent, are indeed modified by the plasma above the actuator and upstream the flat plate. This leads to a local modification of the flow conditions, inducing an increase in the shock wave angle.

Enhanced performance configuration for fast-switching deformed helix ferroelectric liquid crystal continuous tunable Lyot filter.

PubMed

Tam, A M W; Qi, G; Srivastava, A K; Wang, X Q; Fan, F; Chigrinov, V G; Kwok, H S

2014-06-10

In this paper, we present a novel design configuration of double DHFLC wave plate continuous tunable Lyot filter, which exhibits a rapid response time of 185 μs, while the high-contrast ratio between the passband and stop band is maintained throughout a wide tunable range. A DHFLC tunable filter with a high-contrast ratio is attractive for realizing high-speed optical processing devices, such as multispectral and hyperspectral imaging systems, real-time remote sensing, field sequential color display, and wavelength demultiplexing in the metro network. In this work, an experimental prototype for a single-stage DHFLC Lyot filter of this design has been fabricated using photoalignment technology. We have demonstrated that the filter has a continuous tunable range of 30 nm for a blue wavelength, 45 nm for a green wavelength, and more than 50 nm for a red wavelength when the applied voltage gradually increases from 0 to 8 V. Within this tunable range, the contrast ratio of the proposed double wave plate configuration is maintained above 20 with small deviation in the transmittance level. Simulation and experimental results showed the proposed double DHFLC wave plate configuration enhances the contrast ratio of the tunable filter and, thus, increases the tunable range of the filter when compared with the Lyot filter using a single DHFLC wave plate. Moreover, we have proposed a polarization insensitive configuration for which the efficiency of the existing prototype can theoretically be doubled by the use of polarization beam splitters.

Mid-ocean ridges produced thicker crust in the Jurassic than in Recent times

NASA Astrophysics Data System (ADS)

Van Avendonk, H. J.; Harding, J.; Davis, J. K.; Lawver, L. A.

2016-12-01

We present a compilation of published marine seismic refraction data to show that oceanic crust was 1.7 km thicker on average in the mid-Jurassic (170 Ma) than along the present-day mid-ocean ridge system. Plate reconstructions in a fixed hotspot framework show that the thickness of oceanic crust does not correlate with proximity to mantle hotspots, so it is likely that mid-plate volcanism is not the cause of this global trend. We propose that more melt was extracted from the upper mantle beneath mid-ocean ridges in the Jurassic than in recent times. Numerical studies show that temperature increase of 1 degree C in the mantle can lead to approximately 50-70 m thicker crust, so the upper mantle may have cooled 15-20 degrees C/100 Myr since 170 Ma. This average temperature decrease is larger than the secular cooling rate of the Earth's mantle, which is roughly 10 degrees C/100 Myr since the Archean. Apparently, the present-day configuration and dynamics of continental and oceanic plates removes heat more efficiently from the Earth's mantle than in its earlier history. The increase of ocean crustal thickness with plate age is also stronger in the Indian and Atlantic oceans than in the Pacific Ocean basin. This confirms that thermal insulation by the supercontinent Pangaea raised the temperature of the underlying asthenospheric mantle, which in turn led to more magmatic output at the Jurassic mid-ocean ridges of the Indian and Atlantic oceans.

Structural controls on the hydrogeology of the Costa Rica subduction thrust NW of the Osa Peninisula (Invited)

NASA Astrophysics Data System (ADS)

Bangs, N. L.; McIntosh, K. D.; Silver, E. A.; Kluesner, J.; Ranero, C. R.

2013-12-01

Three-dimensional seismic reflection data from the Costa Rica margin NW of the Osa peninsula have enabled us to map the subduction megathrust from the trench to ~12 km subseafloor beneath the shelf. The subduction thrust has a large, abrupt downdip transition in seismic reflection amplitude from very high to low amplitude 6 km subseafloor beneath the upper slope. This transition broadly corresponds with an increase in concentration of microseismic earthquakes potentially due to a significant increase in plate coupling (Bangs et al., 2012, AGU Fall Meeting, T13A-2587), thus linking seismic reflection amplitude to fluid content and mechanical coupling along the fault. A detailed look at the overriding plate reflectivity shows numerous high-amplitude, continuous seismic reflections through the upper plate, many of which are clearly reversed-polarity from the seafloor reflection and are thus likely active fluid conduits through the overriding margin wedge, the slope cover sediment, and the seafloor. Broadly, the structural grain of the margin wedge trends E-W and dips landward across the lower slope and onto the shelf, presumably due to stress imparted by subducting ridges. However, directly above the abrupt high-to-low plate-boundary reflection amplitude transition, structures within the overlying margin wedge reverse dip, steepen, and change strike to an ESE direction. Within this zone we interpret a set of parallel reflections with small offsets and reverse-polarity as high-angle reverse faults that act as fluid conduits leading directly into shallow fluid migration systems described by Bangs et al., 2012 (AGU Fall Meeting, T13A-2587) and Kluesner et al. [this meeting]. The coincidence between the plate-boundary reflection amplitude patterns and the change in structure implies that the fluid migration pathways that drain the plate interface are locally disrupted by overriding plate structure in two possible ways: 1) by focusing up dip fluid migration along the plate interface into a thinner but richer fluid zone along the subduction thrust, or 2) by creating a more direct, nearly vertical route along high-angle reverse faults through the overlying margin wedge to the seafloor (possibly shortened by a factor of two) and draining deeper portions of the plate-boundary more efficiently.

Arc Evolution in Response to the Subduction of Buoyant Features

NASA Astrophysics Data System (ADS)

Jenkins, Luke; Fourel, Loic; Goes, Saskia; Morra, Gabriele

2015-04-01

The subduction of buoyant features such as aseismic ridges or oceanic plateaux has been invoked to explain arc deformation, flat subduction and increase in seismic coupling. Other studies have challenged these ideas, attributing a larger role to the overriding plate. However, many open questions remain about the dynamics of the relative simple case of a single freely subducting plate. How big does a plateau need to be to change the arc shape? What is the control of plate's strength on the impact of buoyant features? How do the velocities adapt to the subduction of less dense material? In the present study, we propose a systematic approach in order to tackle these questions. We use a new 3-D coupled fluid-solid subduction model where the interaction between the slab and the isoviscous mantle is only calculated on the slab surface, significantly increasing computational efficiency. The oceanic plate rheology is visco-elasto-plastic and its top surface is free. We find that arc shape is significantly altered by the subduction of buoyant plateaux. Along the subduction plane through the plateau and depending on its size, the dip angle and the retreat velocity significantly decrease. Flat subduction is obtained in the case of large and strongly buoyant plateau/ridge. An interesting feature is that retreat velocity increases right after the plateau or ridge has finished subducting in order to catch up with the rest of the plate. The gradient in retreat velocity obtained along the trench may cause the slab to have a heterogeneous response to ridge push, eventually leading to slab advance where buoyant material is present. We apply our models to the Izu-Bonin-Marianas (IBM) trench and propose that subduction of the buoyant Caroline Island Ridge at the southern edge of the Mariana trench can explain both trench motion history and the current morphology of the IBM slab as imaged by seismic tomography.

Efficient fabrication method of nano-grating for 3D holographic display with full parallax views.

PubMed

Wan, Wenqiang; Qiao, Wen; Huang, Wenbin; Zhu, Ming; Fang, Zongbao; Pu, Donglin; Ye, Yan; Liu, Yanhua; Chen, Linsen

2016-03-21

Without any special glasses, multiview 3D displays based on the diffractive optics can present high resolution, full-parallax 3D images in an ultra-wide viewing angle. The enabling optical component, namely the phase plate, can produce arbitrarily distributed view zones by carefully designing the orientation and the period of each nano-grating pixel. However, such 3D display screen is restricted to a limited size due to the time-consuming fabricating process of nano-gratings on the phase plate. In this paper, we proposed and developed a lithography system that can fabricate the phase plate efficiently. Here we made two phase plates with full nano-grating pixel coverage at a speed of 20 mm²/mins, a 500 fold increment in the efficiency when compared to the method of E-beam lithography. One 2.5-inch phase plate generated 9-view 3D images with horizontal-parallax, while the other 6-inch phase plate produced 64-view 3D images with full-parallax. The angular divergence in horizontal axis and vertical axis was 1.5 degrees, and 1.25 degrees, respectively, slightly larger than the simulated value of 1.2 degrees by Finite Difference Time Domain (FDTD). The intensity variation was less than 10% for each viewpoint, in consistency with the simulation results. On top of each phase plate, a high-resolution binary masking pattern containing amplitude information of all viewing zone was well aligned. We achieved a resolution of 400 pixels/inch and a viewing angle of 40 degrees for 9-view 3D images with horizontal parallax. In another prototype, the resolution of each view was 160 pixels/inch and the view angle was 50 degrees for 64-view 3D images with full parallax. As demonstrated in the experiments, the homemade lithography system provided the key fabricating technology for multiview 3D holographic display.

A nanostructure based on metasurfaces for optical interconnects

NASA Astrophysics Data System (ADS)

Lin, Shulang; Gu, Huarong

2017-08-01

Optical-electronic Integrated Neural Co-processor takes vital part in optical neural network, which is mainly realized by optical interconnects. Because of the accuracy requirement and long-term goal of integration, optical interconnects should be effective and pint-size. In traditional solutions of optical interconnects, holography built on crystalloid or law of Fresnel diffraction exploited on zone plate was used. However, holographic method cannot meet the efficiency requirement and zone plate is too bulk to make the optical neural unit miniaturization. Thus, this paper aims to find a way to replace holographic method or zone plate with enough diffraction efficiency and smaller size. Metasurfaces are composed of subwavelength-spaced phase shifters at an interface of medium. Metasurfaces allow for unprecedented control of light properties. They also have advanced optical technology of enabling versatile functionalities in a planar structure. In this paper, a nanostructure is presented for optical interconnects. The comparisons of light splitting ability and simulated crosstalk between nanostructure and zone plate are also made.

Refined Zigzag Theory for Laminated Composite and Sandwich Plates

NASA Technical Reports Server (NTRS)

Tessler, Alexander; DiSciuva, Marco; Gherlone, Marco

2009-01-01

A refined zigzag theory is presented for laminated-composite and sandwich plates that includes the kinematics of first-order shear deformation theory as its baseline. The theory is variationally consistent and is derived from the virtual work principle. Novel piecewise-linear zigzag functions that provide a more realistic representation of the deformation states of transverse-shear-flexible plates than other similar theories are used. The formulation does not enforce full continuity of the transverse shear stresses across the plate s thickness, yet is robust. Transverse-shear correction factors are not required to yield accurate results. The theory is devoid of the shortcomings inherent in the previous zigzag theories including shear-force inconsistency and difficulties in simulating clamped boundary conditions, which have greatly limited the accuracy of these theories. This new theory requires only C(sup 0)-continuous kinematic approximations and is perfectly suited for developing computationally efficient finite elements. The theory should be useful for obtaining relatively efficient, accurate estimates of structural response needed to design high-performance load-bearing aerospace structures.

Refined Zigzag Theory for Homogeneous, Laminated Composite, and Sandwich Plates: A Homogeneous Limit Methodology for Zigzag Function Selection

NASA Technical Reports Server (NTRS)

Tessler, Alexander; DiSciuva, Marco; Gherlone, marco

2010-01-01

The Refined Zigzag Theory (RZT) for homogeneous, laminated composite, and sandwich plates is presented from a multi-scale formalism starting with the inplane displacement field expressed as a superposition of coarse and fine contributions. The coarse kinematic field is that of first-order shear-deformation theory, whereas the fine kinematic field has a piecewise-linear zigzag distribution through the thickness. The condition of limiting homogeneity of transverse-shear properties is proposed and yields four distinct sets of zigzag functions. By examining elastostatic solutions for highly heterogeneous sandwich plates, the best-performing zigzag functions are identified. The RZT predictive capabilities to model homogeneous and highly heterogeneous sandwich plates are critically assessed, demonstrating its superior efficiency, accuracy ; and a wide range of applicability. The present theory, which is derived from the virtual work principle, is well-suited for developing computationally efficient CO-continuous finite elements, and is thus appropriate for the analysis and design of high-performance load-bearing aerospace structures.

Slow slip rate and excitation efficiency of deep low-frequency tremors beneath southwest Japan

NASA Astrophysics Data System (ADS)

Daiku, Kumiko; Hiramatsu, Yoshihiro; Matsuzawa, Takanori; Mizukami, Tomoyuki

2018-01-01

We estimated the long-term average slip rate on the plate interface across the Nankai subduction zone during 2002-2013 using deep low-frequency tremors as a proxy for short-term slow slip events based on empirical relations between the seismic moment of short-term slow slip events and tremor activities. The slip rate in each region is likely to compensate for differences between the convergence rate and the slip deficit rate of the subducting Philippine Sea plate estimated geodetically, although the uncertainty is large. This implies that the strain because of the subduction of the plate is partially stored as the slip deficit and partially released by slow slip events during the interseismic period. The excitation efficiency of the tremors for the slow slip events differs among regions: it is high in the northern Kii region. Some events in the western Shikoku region show a somewhat large value. Antigorite serpentinite of two types exists in the mantle wedge beneath southwest Japan. Slips with more effective excitation of tremors presumably occur in high-temperature conditions in the antigorite + olivine stability field. Other slip events with low excitation efficiency are distributed in the antigorite + brucite stability field. Considering the formation reactions of these minerals and their characteristic structures, events with high excitation efficiency can be correlated with a high pore fluid pressure condition. This result suggests that variation in pore fluid pressure on the plate interface affects the magnitude of tremors excited by slow slip events.

Optimization of Uranium Molecular Deposition for Alpha-Counting Sources

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

Monzo, Ellen; Parsons-Moss, Tashi; Genetti, Victoria

2016-12-12

Method development for molecular deposition of uranium onto aluminum 1100 plates was conducted with custom plating cells at Lawrence Livermore National Laboratory. The method development focused primarily on variation of electrode type, which was expected to directly influence plated sample homogeneity. Solid disc platinum and mesh platinum anodes were compared and data revealed that solid disc platinum anodes produced more homogenous uranium oxide films. However, the activity distribution also depended on the orientation of the platinum electrode relative to the aluminum cathode, starting current, and material composition of the plating cell. Experiments demonstrated these variables were difficult to control undermore » the conditions available. Variation of plating parameters among a series of ten deposited plates yielded variations up to 30% in deposition efficiency. Teflon particles were observed on samples plated in Teflon cells, which poses a problem for alpha activity measurements of the plates. Preliminary electropolishing and chemical polishing studies were also conducted on the aluminum 1100 cathode plates.« less

Comparison of Thermal Performances between Low Porosity Perforate Plate and Flat Plate Solar Air Collector

NASA Astrophysics Data System (ADS)

Chan, Hoy-Yen; Vinson, A. A.; Baljit, S. S. S.; Ruslan, M. H.

2018-04-01

Flat plate solar air collector is the most common collector design, which is relatively simpler to fabricate and lower cost. In the present study, perforated plate solar collector was developed to improve the system thermal performance. A glazed perforated plate of 6mm holes diameter with square geometry was designed and installed as the absorber of the collector. The influences of solar radiation intensity and mass flow rate on the thermal performance were investigated. The perforated collector was compared with the flat plate solar collector under the same operating conditions. The highest values of thermal efficiency in this study for the perforated plate (PP) and the flat plate (FP) solar collectors were 59% and 36% respectively, at solar radiation intensity of 846 Wm-2 and mass flow rate of 0.02 kgs-1. Furthermore, PP collector gave better thermal performance compared to FP collector; and compared to previous studies, the present perforated design was compatible with the flat plate with double pass designs.

Solar photovoltaic power systems: an electric utility R & d perspective.

PubMed

Demeo, E A; Taylor, R W

1984-04-20

Solar photovoltaic technology is receiving increasing attention as a prospective source of bulk, electric utility power within the next 10 to 20 years. Successful development will require solar energy conversion efficiencies of about 15 percent for photovoltaic flat-plate modules, or about 25 percent for photovoltaic cells using highly concentrated sunlight. Three different cell technologies have a better than even chance of achieving these target efficiencies with costs and operating lifetimes that would allow significant use by electric utilities. The challenge for the next decade is to push photovoltaic technology to its physical limits while expanding markets and user confidence with currently available systems.

Tandem photovoltaic solar cells and increased solar energy conversion efficiency

NASA Technical Reports Server (NTRS)

Loferski, J. J.

1976-01-01

Tandem photovoltaic cells, as proposed by Jackson (1955) to increase the efficiency of solar energy conversion, involve the construction of a system of stacked p/n homojunction photovoltaic cells composed of different semiconductors. It had been pointed out by critics, however, that the total power which could be extracted from the cells in the stack placed side by side was substantially greater than the power obtained from the stacked cells. A reexamination of the tandem cell concept in view of the development of the past few years is conducted. It is concluded that the use of tandem cell systems in flat plate collectors, as originally envisioned by Jackson, may yet become feasible as a result of the development of economically acceptable solar cells for large scale terrestrial power generation.

Efficient High-Fidelity, Geometrically Exact, Multiphysics Structural Models

DTIC Science & Technology

2011-10-14

fuctionally graded core. International Journal for Numerical Methods in Engineering, 68:940– 966, 2006. 7F. Shang, Z. Wang, and Z. Li. Analysis of...normal deformable plate theory and MLPG method with radial basis fuctions . Composite Structures, 80:539– 552, 2007. 17W. Zhen and W. Chen. A higher-order...functionally graded plates by using higher-order shear and normal deformable plate theory and MLPG method with radial basis fuctions . Composite Structures, 80

Automated Cell Detection and Morphometry on Growth Plate Images of Mouse Bone

PubMed Central

Ascenzi, Maria-Grazia; Du, Xia; Harding, James I; Beylerian, Emily N; de Silva, Brian M; Gross, Ben J; Kastein, Hannah K; Wang, Weiguang; Lyons, Karen M; Schaeffer, Hayden

2014-01-01

Microscopy imaging of mouse growth plates is extensively used in biology to understand the effect of specific molecules on various stages of normal bone development and on bone disease. Until now, such image analysis has been conducted by manual detection. In fact, when existing automated detection techniques were applied, morphological variations across the growth plate and heterogeneity of image background color, including the faint presence of cells (chondrocytes) located deeper in tissue away from the image’s plane of focus, and lack of cell-specific features, interfered with identification of cell. We propose the first method of automated detection and morphometry applicable to images of cells in the growth plate of long bone. Through ad hoc sequential application of the Retinex method, anisotropic diffusion and thresholding, our new cell detection algorithm (CDA) addresses these challenges on bright-field microscopy images of mouse growth plates. Five parameters, chosen by the user in respect of image characteristics, regulate our CDA. Our results demonstrate effectiveness of the proposed numerical method relative to manual methods. Our CDA confirms previously established results regarding chondrocytes’ number, area, orientation, height and shape of normal growth plates. Our CDA also confirms differences previously found between the genetic mutated mouse Smad1/5CKO and its control mouse on fluorescence images. The CDA aims to aid biomedical research by increasing efficiency and consistency of data collection regarding arrangement and characteristics of chondrocytes. Our results suggest that automated extraction of data from microscopy imaging of growth plates can assist in unlocking information on normal and pathological development, key to the underlying biological mechanisms of bone growth. PMID:25525552

Assessment of the scalability of a microtiter plate system for screening of oleaginous microorganisms.

PubMed

Kosa, Gergely; Vuoristo, Kiira S; Horn, Svein Jarle; Zimmermann, Boris; Afseth, Nils Kristian; Kohler, Achim; Shapaval, Volha

2018-06-01

Recent developments in molecular biology and metabolic engineering have resulted in a large increase in the number of strains that need to be tested, positioning high-throughput screening of microorganisms as an important step in bioprocess development. Scalability is crucial for performing reliable screening of microorganisms. Most of the scalability studies from microplate screening systems to controlled stirred-tank bioreactors have been performed so far with unicellular microorganisms. We have compared cultivation of industrially relevant oleaginous filamentous fungi and microalga in a Duetz-microtiter plate system to benchtop and pre-pilot bioreactors. Maximal glucose consumption rate, biomass concentration, lipid content of the biomass, biomass, and lipid yield values showed good scalability for Mucor circinelloides (less than 20% differences) and Mortierella alpina (less than 30% differences) filamentous fungi. Maximal glucose consumption and biomass production rates were identical for Crypthecodinium cohnii in microtiter plate and benchtop bioreactor. Most likely due to shear stress sensitivity of this microalga in stirred bioreactor, biomass concentration and lipid content of biomass were significantly higher in the microtiter plate system than in the benchtop bioreactor. Still, fermentation results obtained in the Duetz-microtiter plate system for Crypthecodinium cohnii are encouraging compared to what has been reported in literature. Good reproducibility (coefficient of variation less than 15% for biomass growth, glucose consumption, lipid content, and pH) were achieved in the Duetz-microtiter plate system for Mucor circinelloides and Crypthecodinium cohnii. Mortierella alpina cultivation reproducibility might be improved with inoculation optimization. In conclusion, we have presented suitability of the Duetz-microtiter plate system for the reproducible, scalable, and cost-efficient high-throughput screening of oleaginous microorganisms.

Generation and Initiation of Plate Tectonics on Terrestrail Planets

NASA Astrophysics Data System (ADS)

Foley, Bradford J.

The question of why plate tectonics occurs on Earth, but not on the other planets of our solar system, is one of the most fundamental issues in geophysics and planetary science. I study this problem using numerical simulations of mantle convection with a damage-grainsize feedback (grain-damage) to constrain the conditions necessary for plate tectonics to occur on a terrestrial planet, and how plate tectonics initiates. In Chapter 2, I use numerical simulations to determine how large a viscosity ratio, between pristine lithosphere and mantle, damage can offset to allow mobile (plate-like) convection. I then use the numerical results to formulate a new scaling law to describe the boundary between stagnant lid and plate-like regimes of mantle convection. I hypothesize that damage must reduce the viscosity of shear zones in the lithosphere to a critical value, equivalent to the underlying mantle viscosity, in order for plate tectonics to occur, and demonstrate that a scaling law based on this hypothesis reproduces the numerical results. For the Earth, damage is efficient in the lithosphere and provides a viable mechanism for the operation of plate tectonics. I apply my theory to super-Earths and map out the transition between plate-like and stagnant lid convection with a "planetary plate-tectonic phase" diagram in planet size-surface temperature space. Both size and surface temperature are important, with plate tectonics being favored for larger, cooler planets. This gives a natural explanation for Earth, Venus, and Mars, and implies that plate tectonics on exoplanets should correlate with size, incident solar radiation, and atmospheric composition. In Chapters 3 and 4 I focus on the initiation of plate tectonics. In Chapter 3, I develop detailed scaling laws describing plate speed and heat flow for mantle convection with grain-damage across a wide parameter range, with the intention of applying these scaling laws to the early Earth in Chapter 4. Convection with grain-damage scales differently than Newtonian convection; whereas the Nusselt number, Nu, typically scales with the Rayleigh number, Ra, to the 1/3 power, for grain-damage this exponent is larger because increasing Ra also enhances damage. In addition, Nu and plate velocity are also functions of the damage to healing ratio, (D/H); increasing D/H increases Nu (or plate speed) because more damage leads to more vigorous convection. In Chapter 4, I demonstrate that subduction can be sustained on the early Earth, that the style of subduction at this time was different than modern day plate tectonics, and that such subduction (or proto-subduction) can initiate rapidly after magma ocean solidification. The scaling laws from Chapter 3 show that, though either higher interior mantle temperatures or higher surface temperatures lead to slower plates, proto-subduction, with plate speeds of at least 1.5 cm/yr, can still be maintained in the Hadean, even if the primordial atmosphere was CO2 rich. Furthermore, when the interior mantle temperature is high (e.g. above ≈ 2000 K), the mode of subduction switches to a "sluggish subduction" style, where downwellings are more drip-like than slab-like and plate boundaries are more diffuse. Numerical models of post-magma ocean mantle convection, and a scaling analysis based on the results of these models, demonstrate that proto-plate tectonics likely initiates within ˜100 Myrs of magma ocean solidification. Combined with the conclusion that proto-subduction could be maintained on the early Earth, my results are consistent with evidence for Hadean subduction from zircon data, and indicate that the subduction inferred from zircons may have been distinct from modern day plate tectonics. After the initiation of proto-subduction, which occurs as a rapid overturn of the whole lithosphere, mobile lid convection takes place as non-plate tectonic "sluggish subduction" As both the mantle interior and climate cool, modern style plate tectonics develops. The rapid, initial subduction event may help hasten the onset of modern style plate tectonics by drawing excess CO 2 out of the atmosphere and cooling the climate.

Potential of thin-film solar cell module technology

NASA Technical Reports Server (NTRS)

Shimada, K.; Ferber, R. R.; Costogue, E. N.

1985-01-01

During the past five years, thin-film cell technology has made remarkable progress as a potential alternative to crystalline silicon cell technology. The efficiency of a single-junction thin-film cell, which is the most promising for use in flat-plate modules, is now in the range of 11 percent with 1-sq cm cells consisting of amorphous silicon, CuInSe2 or CdTe materials. Cell efficiencies higher than 18 percent, suitable for 15 percent-efficient flat plate modules, would require a multijunction configuration such as the CdTe/CuInSe2 and tandem amorphous-silicon (a-Si) alloy cells. Assessments are presented of the technology status of thin-film-cell module research and the potential of achieving the higher efficiencies required for large-scale penetration into the photovoltaic (PV) energy market.

Optimizing a spectral element for modeling PZT-induced Lamb wave propagation in thin plates

NASA Astrophysics Data System (ADS)

Ha, Sungwon; Chang, Fu-Kuo

2010-01-01

Use of surface-mounted piezoelectric actuators to generate acoustic ultrasound has been demonstrated to be a key component of built-in nondestructive detection evaluation (NDE) techniques, which can automatically inspect and interrogate damage in hard-to-access areas in real time without disassembly of the structural parts. However, piezoelectric actuators create complex waves, which propagate through the structure. Having the capability to model piezoelectric actuator-induced wave propagation and understanding its physics are essential to developing advanced algorithms for the built-in NDE techniques. Therefore, the objective of this investigation was to develop an efficient hybrid spectral element for modeling piezoelectric actuator-induced high-frequency wave propagation in thin plates. With the hybrid element we take advantage of both a high-order spectral element in the in-plane direction and a linear finite element in the thickness direction in order to efficiently analyze Lamb wave propagation in thin plates. The hybrid spectral element out-performs other elements in terms of leading to significantly faster computation and smaller memory requirements. Use of the hybrid spectral element is proven to be an efficient technique for modeling PZT-induced (PZT: lead zirconate titanate) wave propagation in thin plates. The element enables fundamental understanding of PZT-induced wave propagation.

On improving the efficiency of tensor voting.

PubMed

Moreno, Rodrigo; Garcia, Miguel Angel; Puig, Domenec; Pizarro, Luis; Burgeth, Bernhard; Weickert, Joachim

2011-11-01

This paper proposes two alternative formulations to reduce the high computational complexity of tensor voting, a robust perceptual grouping technique used to extract salient information from noisy data. The first scheme consists of numerical approximations of the votes, which have been derived from an in-depth analysis of the plate and ball voting processes. The second scheme simplifies the formulation while keeping the same perceptual meaning of the original tensor voting: The stick tensor voting and the stick component of the plate tensor voting must reinforce surfaceness, the plate components of both the plate and ball tensor voting must boost curveness, whereas junctionness must be strengthened by the ball component of the ball tensor voting. Two new parameters have been proposed for the second formulation in order to control the potentially conflictive influence of the stick component of the plate vote and the ball component of the ball vote. Results show that the proposed formulations can be used in applications where efficiency is an issue since they have a complexity of order O(1). Moreover, the second proposed formulation has been shown to be more appropriate than the original tensor voting for estimating saliencies by appropriately setting the two new parameters.

Secondary barrier construction for low temperature liquefied gas storage tank carrying vessels

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

Okamoto, T.; Nishimoto, T.; Sawada, K.

1978-12-05

A new LNG-cargo-tank secondary barrier developed by Japan's Hitachi Shipbuilding and Engineering Co., Ltd., offers ease of fabrication, simple construction, improved efficiency of installation, and protection against seawater ingress as well as LNG leakage. The secondary barrier, intended for use below spherical LNG tanks, consists of unit heat-insulating block plates adhesively secured to the bottom plate of the ship's hold, heat-insulating filling members stuffed into the joints between the block plates, and a protective layer formed on the entire surface of the block plates and the filling members. These unit block plates are in the form of heat-insulating members ofmore » the required thickness, preformed into a square or trapezoidal shape, particularly in the form of rigid-foam synthetic-resin plates.« less

Influence of the wavelet order on proper damage location in plate structures

NASA Astrophysics Data System (ADS)

Pawlak, Zdzisław; Knitter-Piątkowska, Anna

2018-01-01

The rectangular thin plates were analyzed in the paper. The static response in plate structure subjected to the uniform load was derived by applying the finite element method. In the dynamic, experimental tests the accelerations were obtained with the use of modal hammer and DEWEsoft® software. Next, the analysis of the signal was carried out with the use of Discrete Wavelet Transform (DWT), provided that damage exists in the considered plate structure. It was assumed, that in the middle of the structure a certain area of the plate is thinner or there is a crack across the entire plate thickness. The aim of this work was to choose the appropriate wavelet order to reveal the localization of defect. The results of selected numerical example proved the efficiency of proposed approach.

Calculating the electric field in real human head by transcranial magnetic stimulation with shield plate

NASA Astrophysics Data System (ADS)

Lu, Mai; Ueno, Shoogo

2009-04-01

In this paper, we present a transcranial magnetic stimulation (TMS) system by incorporating a conductive shield plate. The magnetic field, induced current density, and electric field in a real human head were calculated by impedance method and the results were compared with TMS without shielding. Our results show that the field localization can be improved by introducing a conductive shield plate; the stimulation magnitude (depth) in the brain is reduced comparing with the TMS without shielding. The strong magnetic field near the TMS coil is difficult to be efficiently shielded by a thinner conductive shield plate.

Effect of calcium ions on the evolution of biofouling by Bacillus subtilis in plate heat exchangers simulating the heat pump system used with treated sewage in the 2008 Olympic Village.

PubMed

Tian, Lei; Chen, Xiao Dong; Yang, Qian Peng; Chen, Jin Chun; Shi, Lin; Li, Qiong

2012-06-01

Heat pump systems using treated sewage water as the heat source were used in the Beijing Olympic Village for domestic heating and cooling. However, considerable biofouling occurred in the plate heat exchangers used in the heat pump system, greatly limiting the system efficiency. This study investigates the biofouling characteristics using a plate heat exchanger in parallel with a flow cell system to focus on the effect of calcium ions on the biofilm development. The interactions between the microorganisms and Ca(2+) enhances both the extent and the rate of biofilm development with increasing Ca(2+) concentration, leading to increased heat transfer and flow resistances. Three stages of biofouling development were identified in the presence of Ca(2+) from different biofouling mass growth rates with an initial stage, a rapid growth stage and an extended growth stage. Each growth stage had different biofouling morphologies influenced by the Ca(2+) concentration. The effects of Ca(2+) on the biofouling heat transfer and flow resistances had a synergistic effect related to both the biofouling mass and the morphology. The effect of Ca(2+) on the biofouling development was most prominent during the rapid growth stage. Copyright © 2012 Elsevier B.V. All rights reserved.

Simulation study of disruption characteristics in KSTAR

NASA Astrophysics Data System (ADS)

Lee, Jongkyu; Kim, J. Y.; Kessel, C. E.; Poli, F.

2012-10-01

A detailed simulation study of disruption in KSTAR had been performed using the Tokamak Simulation Code(TSC) [1] during the initial design phase of KSTAR [2]. Recently, however, a partial modification in the structure of passive plate was made in relation to reduce eddy current and increase the efficiency of control of vertical position. A substantial change can then occur in disruption characteristics and plasma behavior during disruption due to changes in passive plate structure. Because of this, growth rate of vertical instability is expected to be increased and eddy current and its associated electomagnetic force are expected to be reduced. To check this in more detail, a new simulation study is here given with modified passive plate structure of KSTAR. In particular, modeling of vertical disruption that is vertical displacement event (VDE) was carried out. We calculated vertical growth rate for a drift phase of plasma and electromagnetic force acting on PFC structures and compared the results between in a new model and an old model. [4pt] [1] S.C. Jardin, N. Pomphrey and J. Delucia, J. Comp. Phys. 66, 481 (1986).[0pt] [2] J.Y. Kim, S.Y. Cho and KSTAR Team, Disruption load analysis on KSTAR PFC structures, J. Accel. Plasma Res. 5, 149 (2000).

Design and function of biomimetic multilayer water purification membranes

PubMed Central

Ling, Shengjie; Qin, Zhao; Huang, Wenwen; Cao, Sufeng; Kaplan, David L.; Buehler, Markus J.

2017-01-01

Multilayer architectures in water purification membranes enable increased water throughput, high filter efficiency, and high molecular loading capacity. However, the preparation of membranes with well-organized multilayer structures, starting from the nanoscale to maximize filtration efficiency, remains a challenge. We report a complete strategy to fully realize a novel biomaterial-based multilayer nanoporous membrane via the integration of computational simulation and experimental fabrication. Our comparative computational simulations, based on coarse-grained models of protein nanofibrils and mineral plates, reveal that the multilayer structure can only form with weak interactions between nanofibrils and mineral plates. We demonstrate experimentally that silk nanofibril (SNF) and hydroxyapatite (HAP) can be used to fabricate highly ordered multilayer membranes with nanoporous features by combining protein self-assembly and in situ biomineralization. The production is optimized to be a simple and highly repeatable process that does not require sophisticated equipment and is suitable for scaled production of low-cost water purification membranes. These membranes not only show ultrafast water penetration but also exhibit broad utility and high efficiency of removal and even reuse (in some cases) of contaminants, including heavy metal ions, dyes, proteins, and other nanoparticles in water. Our biomimetic design and synthesis of these functional SNF/HAP materials have established a paradigm that could lead to the large-scale, low-cost production of multilayer materials with broad spectrum and efficiency for water purification, with applications in wastewater treatment, biomedicine, food industry, and the life sciences. PMID:28435877

Design and function of biomimetic multilayer water purification membranes.

PubMed

Ling, Shengjie; Qin, Zhao; Huang, Wenwen; Cao, Sufeng; Kaplan, David L; Buehler, Markus J

2017-04-01

Multilayer architectures in water purification membranes enable increased water throughput, high filter efficiency, and high molecular loading capacity. However, the preparation of membranes with well-organized multilayer structures, starting from the nanoscale to maximize filtration efficiency, remains a challenge. We report a complete strategy to fully realize a novel biomaterial-based multilayer nanoporous membrane via the integration of computational simulation and experimental fabrication. Our comparative computational simulations, based on coarse-grained models of protein nanofibrils and mineral plates, reveal that the multilayer structure can only form with weak interactions between nanofibrils and mineral plates. We demonstrate experimentally that silk nanofibril (SNF) and hydroxyapatite (HAP) can be used to fabricate highly ordered multilayer membranes with nanoporous features by combining protein self-assembly and in situ biomineralization. The production is optimized to be a simple and highly repeatable process that does not require sophisticated equipment and is suitable for scaled production of low-cost water purification membranes. These membranes not only show ultrafast water penetration but also exhibit broad utility and high efficiency of removal and even reuse (in some cases) of contaminants, including heavy metal ions, dyes, proteins, and other nanoparticles in water. Our biomimetic design and synthesis of these functional SNF/HAP materials have established a paradigm that could lead to the large-scale, low-cost production of multilayer materials with broad spectrum and efficiency for water purification, with applications in wastewater treatment, biomedicine, food industry, and the life sciences.

A refined finite element method for bending analysis of laminated plates integrated with piezoelectric fiber-reinforced composite actuators

NASA Astrophysics Data System (ADS)

Rouzegar, J.; Abbasi, A.

2018-03-01

This research presents a finite element formulation based on four-variable refined plate theory for bending analysis of cross-ply and angle-ply laminated composite plates integrated with a piezoelectric fiber-reinforced composite actuator under electromechanical loading. The four-variable refined plate theory is a simple and efficient higher-order shear deformation theory, which predicts parabolic variation of transverse shear stresses across the plate thickness and satisfies zero traction conditions on the plate free surfaces. The weak form of governing equations is derived using the principle of minimum potential energy, and a 4-node non-conforming rectangular plate element with 8 degrees of freedom per node is introduced for discretizing the domain. Several benchmark problems are solved by the developed MATLAB code and the obtained results are compared with those from exact and other numerical solutions, showing good agreement.

Optically stimulated luminescence in an imaging plate using BaFi:Eu.

PubMed

Nanto, H; Araki, T; Daimon, M; Kusano, E; Kinbara, A; Kawabata, K; Nakano, Y

2002-01-01

BaFI:Eu phosphors are fabricated using a new method of synthesis: liquid phase synthesis, in which the phosphor particles are formed through the association of Ba2+ ions, F-ions and Eu2+ ions in solution. An intense optically stimulated luminescence (OSL) peak at about 410 nm is observed by stimulating X ray irradiated BaFI:Eu phosphor with about 550-750 nm light. It is found that the peak wavelength of the optically stimulation spectrum is about 690 nm. This result suggests that the semiconductor laser can be used as the stimulating light source. It is also found that the OSL intensity is increased with increasing the X ray dose. The BaFI:Eu phosphor as a photostimulable material for the imaging plate of a computed radiography system provides the following advantages; (1) high X ray absorption coefficient, (2) high monodispersion in size which would contribute to sharp images, (3) high OSL and thus low luminescence mottle and (4) high DQE (detective quantum efficiency).

Photon-counting image sensors for the ultraviolet

NASA Technical Reports Server (NTRS)

Jenkins, E. B.

1985-01-01

An investigation on specific performance details of photon counting, ultraviolet image sensors having 2-dimensional formats is reviewed. In one study, controlled experiments were performed which compare the quantum efficiencies, in pulse counting mode, of CsI photocathodes deposited on: (1) the front surface of a microchannel plate (MCP), (2) a solid surface in front of an MCP, and (3) an intensified CCD image sensor (ICCD) where a CCD is directly bombarded by accelerated photoelectrons. Tests indicated that the detection efficiency of the CsI-coated MCP at 1026 A is lower by a factor of 2.5 than that of the MCP with a separate, opaque CsI photocathode, and the detection efficiency ratio increases substantially at longer wavelengths (ratio is 5 at 1216 A and 20 at 1608 A).

Thinner, More-Efficient Oxygen-Separation Cells

NASA Technical Reports Server (NTRS)

Clark, Douglas J.; Galica, Leo M.; Losey, Robert W.

1992-01-01

Better gas-distribution plates fabricated more easily. Oxygen-separation cell redesigned to make it more efficient, smaller, lighter, and easier to manufacture. Potential applications include use as gas separators, filters, and fuel cells.

Sintering behavior and thermal conductivity of nickel-coated graphite flake/copper composites fabricated by spark plasma sintering

NASA Astrophysics Data System (ADS)

Xu, Hui; Chen, Jian-hao; Ren, Shu-bin; He, Xin-bo; Qu, Xuan-hui

2018-04-01

Nickel-coated graphite flakes/copper (GN/Cu) composites were fabricated by spark plasma sintering with the surface of graphite flakes (GFs) being modified by Ni-P electroless plating. The effects of the phase transition of the amorphous Ni-P plating and of Ni diffusion into the Cu matrix on the densification behavior, interfacial microstructure, and thermal conductivity (TC) of the GN/Cu composites were systematically investigated. The introduction of Ni-P electroless plating efficiently reduced the densification temperature of uncoated GF/Cu composites from 850 to 650°C and slightly increased the TC of the X-Y basal plane of the GF/Cu composites with 20vol%-30vol% graphite flakes. However, when the graphite flake content was greater than 30vol%, the TC of the GF/Cu composites decreased with the introduction of Ni-P plating as a result of the combined effect of the improved heat-transfer interface with the transition layer, P generated at the interface, and the diffusion of Ni into the matrix. Given the effect of the Ni content on the TC of the Cu matrix and on the interface thermal resistance, a modified effective medium approximation model was used to predict the TC of the prepared GF/Cu composites.

Separation of airborne and structureborne noise radiated by plates constructed of conventional and composite materials with applications for prediction of interior noise paths in propeller driven aircraft. Ph.D. Thesis

NASA Technical Reports Server (NTRS)

Mcgary, M. C.

1986-01-01

The anticipated application of advanced turboprop propulsion systems and use of composite materials in primary structure is expected to increase the interior noise of future aircraft to unacceptability high levels. The absence of technically and economically feasible noise source-path diagnostic tools has been a primer obstacle in the development of efficient noise control treatments for propeller driven aircraft. A new diagnostic method which permits the separation and prediction of the fully coherent airborne and structureborne components of the sound radiated by plates or thin shells has been developed. Analytical and experimental studies of the proposed method were performed on plates constructed of both conventional and composite materials. The results of the study indicate that the proposed method can be applied to a variety of aircraft materials, could be used in flight, and has fewer encumbrances than the other diagnostic tools currently available. The study has also revealed that the noise radiation of vibrating plates in the low frequency regime due to combined airborne and structureborne inputs possesses a strong synergistic nature. The large influence of the interaction between the airborne and structureborne terms has been hitherto ignored by researchers of aircraft interior noise problems.

Customized mandibular reconstruction plates improve mechanical performance in a mandibular reconstruction model

PubMed Central

Gutwald, Ralf; Jaeger, Raimund; Lambers, Floor M.

2017-01-01

Abstract The purpose of this paper was to analyze the biomechanical performance of customized mandibular reconstruction plates with optimized strength. The best locations for increasing bar widths were determined with a sensitivity analysis. Standard and customized plates were mounted on mandible models and mechanically tested. Maximum stress in the plate could be reduced from 573 to 393 MPa (−31%) by increasing bar widths. The median fatigue limit was significantly greater (p < 0.001) for customized plates (650 ± 27 N) than for standard plates (475 ± 27 N). Increasing bar widths at case-specific locations was an effective strategy for increasing plate fatigue performance. PMID:27887036

Metallic metasurfaces for high efficient polarization conversion control in transmission mode.

PubMed

Li, Tong; Hu, Xiaobin; Chen, Huamin; Zhao, Chen; Xu, Yun; Wei, Xin; Song, Guofeng

2017-10-02

A high efficient broadband polarization converter is an important component in integrated miniaturized optical systems, but its performances is often restricted by the material structures, metallic metasurfaces for polarization control in transmission mode never achieved efficiency above 0.5. Herein, we theoretically demonstrate that metallic metasurfaces constructed by thick cross-shaped particles can realize a high efficient polarization transformation over a broadband. We investigated the resonant properties of designed matesurfaces and found that the interaction between double FP cavity resonances and double bulk magnetic resonances is the main reason to generate a high transmissivity over a broadband. In addition, through using four resonances effect and tuning the anisotropic optical response, we realized a high efficient (> 0.85) quarter-wave plate at the wavelength range from 1175nm to 1310nm and a high efficient (> 0.9) half-wave plate at the wavelength range from 1130nm to 1230nm. The proposed polarization converters may have many potential applications in integrated polarization conversion devices and optical data storage systems.

Flat-plate solar array project. Volume 4: High-efficiency solar cells

NASA Technical Reports Server (NTRS)

Leipold, M.; Cheng, L.; Daud, T.; Mokashi, A.; Burger, D.; Christensen, E. (Editor); Murry, J. (Editor); Bengelsdorf, I. (Editor)

1986-01-01

The High Efficiency Solar Cell Task was assigned the objective of understanding and developing high efficiency solar cell devices that would meet the cost and performance goals of the Flat Plate Solar Array (FSA) Project. The need for research dealing with high efficiency devices was considered important because of the role efficiency plays in reducing price per watt of generated energy. The R&D efforts conducted during the 1982 to 1986 period are summarized to provide understanding and control of energy conversion losses associated with crystalline silicon solar cells. New levels of conversion efficiency were demonstrated. Major contributions were made both to the understanding and reduction of bulk and surface losses in solar cells. For example, oxides, nitrides, and polysilicon were all shown to be potentially useful surface passivants. Improvements in measurement techniques were made and Auger coefficients and spectral absorption data were obtained for unique types of silicon sheets. New modelling software was developed including a program to optimize a device design based on input characteristics of a cell.

Drag Measurements over Embedded Cavities in a Low Reynolds Number Couette Flow

NASA Astrophysics Data System (ADS)

Gilmer, Caleb; Lang, Amy; Jones, Robert

2010-11-01

Recent research has revealed that thin-walled, embedded cavities in low Reynolds number flow have the potential to reduce the net viscous drag force acting on the surface. This reduction is due to the formation of embedded vortices allowing the outer flow to pass over the surface via a roller bearing effect. It is also hypothesized that the scales found on butterfly wings may act in a similar manner to cause a net increase in flying efficiency. In this experimental study, rectangular embedded cavities were designed as a means of successfully reducing the net drag across surfaces in a low Reynolds number flow. A Couette flow was generated via a rotating conveyor belt immersed in a tank of high viscosity mineral oil above which the plates with embedded cavities were placed. Drag induced on the plate models was measured using a force gauge and compared directly to measurements acquired over a flat plate. Various cavity aspect ratios and gap heights were tested in order to determine the conditions under which the greatest drag reductions occurred.

A novel integration system of magnetically immobilized cells and a pair of graphite plate-stainless iron mesh electrodes for the bioremediation of coking wastewater.

PubMed

Jiang, Bei; Tan, Liang; Ning, Shuxiang; Shi, Shengnan

2016-09-01

Magnetically immobilized cells of Comamonas sp. JB coupling with electrode reaction was developed to enhance the treatment efficiency of coking wastewater containing phenol, carbazole (CA), dibenzofuran (DBF), and dibenzothiophene (DBT). The pair of graphite plate-stainless iron mesh electrodes was chosen as the most suitable electrodes. Magnetically immobilized cells coupling with graphite plate-stainless iron mesh electrodes (coupling system) exhibited high degradation activity for all the compounds, which were significantly higher than the sum by single magnetically immobilized cells and electrode reaction at the optimal voltage. Recycling experiments demonstrated that the degradation activity of coupling system increased gradually during eight recycles, indicating that there was a coupling effect between the biodegradation and electrode reaction. Phenol hydroxylase and qPCR assays confirmed that appropriate electrical stimulation could improve phenol hydroxylase activity and promote cells growth. Toxicity assessment suggested the treatment of the coking wastewater by coupling system led to less toxicity than untreated wastewater. Copyright © 2016 Elsevier Ltd. All rights reserved.

Characterization of laser beam transmission through a High Density Polyethylene (HDPE) plate

NASA Astrophysics Data System (ADS)

Genna, S.; Leone, C.; Tagliaferri, V.

2017-02-01

Infrared (IR) light propagation in semicrystalline polymers involves mechanisms such as reflection, transmission, absorption and internal scattering. These different rates determine either the interaction mechanism, either the temperatures reached in the IR heating processes. Consequently, the knowledge of these rates is fundamental in the development of IR heating processes in order to avoid the polymer's damage and to increase the process energy efficiency. Aim of this work is to assess a simple procedure to determine the rates of absorbed, reflected, transmitted and scattered energy in the case of an unfilled High Density Polyethylene (HDPE) plate. Experimental tests were performed by exposing a HDPE plate, 3 mm in thickness, to a diode laser source, working at the fundamental wavelength of 975 nm. The transmitted power was measured by power meter, the reflected one by applying the Beer-Lambert law to sample of different thickness. IR thermal images were adopted to measure the absorbed ratio. The scattered ratio was measured by energetic balance, as difference between the incoming power and the other ratios. Finally, IR thermal images were adopted to measure the scattered ratio and to validate the procedure.

Comparison of two temperature control techniques in a forced water heater solar system

NASA Astrophysics Data System (ADS)

Hernández, E.; E Guzmán, R.; Santos, A.; Cordoba, E.

2017-12-01

a study on the performance of a forced solar heating system in which a comparative analysis of two control strategies, including the classic on-off control and PID control is presented. From the experimental results it was found that the two control strategies show a similar behaviour in the solar heating system forced an approximate settling time of 60 min and over-elongation 2°C for the two control strategies. Furthermore, the maximum temperature in the storage tank was 46°C and the maximum efficiency of flat plate collector was 76.7% given that this efficiency is the ratio of the energy of the radiation on the collector and the energy used to heat water. The efficiency obtained is a fact well accepted because the business efficiencies of flat plate collectors are approximately 70%.

Note: High-efficiency broadband acoustic energy harvesting using Helmholtz resonator and dual piezoelectric cantilever beams

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

Yang, Aichao; Li, Ping, E-mail: liping@cqu.edu.cn; Wen, Yumei

2014-06-15

A high-efficiency broadband acoustic energy harvester consisting of a compliant-top-plate Helmholtz resonator (HR) and dual piezoelectric cantilever beams is proposed. Due to the high mechanical quality factor of beams and the strong multimode coupling of HR cavity, top plate and beams, the high efficiency in a broad bandwidth is obtained. Experiment exhibits that the proposed harvester at 170–206 Hz has 28–188 times higher efficiency than the conventional harvester using a HR with a piezoelectric composite diaphragm. For input acoustic pressure of 2.0 Pa, the proposed harvester exhibits 0.137–1.43 mW output power corresponding to 0.035–0.36 μW cm{sup −3} volume power density atmore » 170–206 Hz.« less

Frequency Response of an Aircraft Wing with Discrete Source Damage Using Equivalent Plate Analysis

NASA Technical Reports Server (NTRS)

Krishnamurthy, T.; Eldred, Lloyd B.

2007-01-01

An equivalent plate procedure is developed to provide a computationally efficient means of matching the stiffness and frequencies of flight vehicle wing structures for prescribed loading conditions. Several new approaches are proposed and studied to match the stiffness and first five natural frequencies of the two reference models with and without damage. One approach divides the candidate reference plate into multiple zones in which stiffness and mass can be varied using a variety of materials including aluminum, graphite-epoxy, and foam-core graphite-epoxy sandwiches. Another approach places point masses along the edge of the stiffness-matched plate to tune the natural frequencies. Both approaches are successful at matching the stiffness and natural frequencies of the reference plates and provide useful insight into determination of crucial features in equivalent plate models of aircraft wing structures.

Ellipsoidal and parabolic glass capillaries as condensers for x-ray microscopes.

PubMed

Zeng, Xianghui; Duewer, Fred; Feser, Michael; Huang, Carson; Lyon, Alan; Tkachuk, Andrei; Yun, Wenbing

2008-05-01

Single-bounce ellipsoidal and paraboloidal glass capillary focusing optics have been fabricated for use as condenser lenses for both synchrotron and tabletop x-ray microscopes in the x-ray energy range of 2.5-18 keV. The condenser numerical apertures (NAs) of these devices are designed to match the NA of x-ray zone plate objectives, which gives them a great advantage over zone plate condensers in laboratory microscopes. The fabricated condensers have slope errors as low as 20 murad rms. These capillaries provide a uniform hollow-cone illumination with almost full focusing efficiency, which is much higher than what is available with zone plate condensers. Sub-50 nm resolution at 8 keV x-ray energy was achieved by utilizing this high-efficiency condenser in a laboratory microscope based on a rotating anode generator.

High resolution, two-dimensional imaging, microchannel plate detector for use on a sounding rocket experiment

NASA Technical Reports Server (NTRS)

Bush, Brett C.; Cotton, Daniel M.; Siegmund, Oswald H.; Chakrabarti, Supriya; Harris, Walter; Clarke, John

1991-01-01

We discuss a high resolution microchannel plate (MCP) imaging detector to be used in measurements of Doppler-shifted hydrogen Lyman-alpha line emission from Jupiter and the interplanetary medium. The detector is housed in a vacuum-tight stainless steel cylinder (to provide shielding from magnetic fields) with a MgF2 window. Operating at nominal voltage, the four plate configuration provides a gain of 1.2 x 10 exp 7 electrons per incident photon. The wedge-and-strip anode has two-dimensional imaging capabilities, with a resolution of 40 microns FWHM over a one centimeter diameter area. The detector has a high quantum efficiency while retaining a low background rate. A KBr photocathode is used to enhance the quantum efficiency of the bare MCPs to a value of 35 percent at Lyman-alpha.

3-D Simulation of Tectonic Evolution in Mariana with a Coupled Model of Plate Subduction and Back-Arc Spreading

NASA Astrophysics Data System (ADS)

Hashima, A.; Matsu'Ura, M.

2006-12-01

We obtained the expressions for internal deformation fields due to a moment tensor in an elastic-viscoelastic layered holf-space. This unified formulation of internal deformation fields for shear faulting and crack opening enabled us to deal with the problem of tectonic deformation at a composite type of plate boundary zones. The tectonic deformation can be ascribed to mechanical interaction at plate boundaries, which make a closed circuit with the mode of relative plate motion changing from divergence to convergence through transcurrent motion. One of the rational ways to represent mechanical interaction at plate boundaries is specifying the increase rates of normal or tangential displacement discontinuity across plate interfaces. On the basis of such a basic idea we developed a 3-D simulation model for the nonlinear, coupled system of plate subduction and back-arc spreading in Mariana. Through numerical simulations we revealed the evolution process of back-arc spreading. At the first stage, steady plate subduction (shear faulting at a plate interface) gradually forms tensile stress fields in the back-arc region of the overriding plate. When the accumulated tensile stress reaches a critical level, back-arc spreading (crack opening) starts at a structurally weak portion of the overriding plate. The horizontal motion of the frontal part of the overriding plate due to back-arc spreading pushes out the plate boundary toward the oceanic plate. In steady-state plate subduction the shear stress acting on a plate interface must balance with the maximum frictional resistance (shear strength) of the plate interface. Therefore, the increase of shear stress at the plate interface leads to the increase of slip rate at the plate interface. The local increase of slip rate at the plate interface produces the additional tensile stress in the back-arc region. The increased tensile stress must be canceled out by the additional crack opening. Such a feedback mechanism between plate subduction and back-arc spreading is crucial to understand the development of back-ark spreading.

Room-temperature synthesis of zinc oxide nanoparticles in different media and their application in cyanide photodegradation

PubMed Central

2013-01-01

Cyanide is an extreme hazard and extensively found in the wastes of refinery, coke plant, and metal plating industries. A simple, fast, cost-effective, room-temperature wet chemical route, based on cyclohexylamine, for synthesizing zinc oxide nanoparticles in aqueous and enthanolic media was established and tested for the photodegradation of cyanide ions. Particles of polyhedra morphology were obtained for zinc oxide, prepared in ethanol (ZnOE), while spherical and some chunky particles were observed for zinc oxide, prepared in water (ZnOW). The morphology was crucial in enhancing the cyanide ion photocatalytic degradation efficiency of ZnOE by a factor of 1.5 in comparison to the efficiency of ZnOW at an equivalent concentration of 0.02 wt.% ZnO. Increasing the concentration wt.% of ZnOE from 0.01 to 0.09 led to an increase in the photocatalytic degradation efficiency from 85% to almost 100% after 180 min and a doubling of the first-order rate constant (k). PMID:24314056

Assessment of a Thermoelectric Vest through Physical and Mental Performance

DTIC Science & Technology

2012-04-01

system is a sandwich- type structure of doped bismuth telluride (Bi2Te3) soldered between two ceramic plates. Bi2Te3 acts as a semiconductor and after... doping , the material becomes an efficient TE. Variations in doping create P-N junctions throughout the TE. Figure 3 shows a schematic of a TE...Excalibur Sport Ergonometer was used to increase subject’s core body temperature. The Excalibur Sport is a multi-adjustable ergonometer and is

Static bending deflection and free vibration analysis of moderate thick symmetric laminated plates using multidimensional wave digital filters

NASA Astrophysics Data System (ADS)

Tseng, Chien-Hsun

2018-06-01

This paper aims to develop a multidimensional wave digital filtering network for predicting static and dynamic behaviors of composite laminate based on the FSDT. The resultant network is, thus, an integrated platform that can perform not only the free vibration but also the bending deflection of moderate thick symmetric laminated plates with low plate side-to-thickness ratios (< = 20). Safeguarded by the Courant-Friedrichs-Levy stability condition with the least restriction in terms of optimization technique, the present method offers numerically high accuracy, stability and efficiency to proceed a wide range of modulus ratios for the FSDT laminated plates. Instead of using a constant shear correction factor (SCF) with a limited numerical accuracy for the bending deflection, an optimum SCF is particularly sought by looking for a minimum ratio of change in the transverse shear energy. This way, it can predict as good results in terms of accuracy for certain cases of bending deflection. Extensive simulation results carried out for the prediction of maximum bending deflection have demonstratively proven that the present method outperforms those based on the higher-order shear deformation and layerwise plate theories. To the best of our knowledge, this is the first work that shows an optimal selection of SCF can significantly increase the accuracy of FSDT-based laminates especially compared to the higher order theory disclaiming any correction. The highest accuracy of overall solution is compared to the 3D elasticity equilibrium one.

Anomalous Buckling Characteristics of Laminated Metal-Matrix Composite Plates with Central Square Holes

NASA Technical Reports Server (NTRS)

Ko, William L.

1998-01-01

Compressive buckling analysis was performed on metal-matrix composite (MMC) plates with central square holes. The MMC plates have varying aspect ratios and hole sizes and are supported under different boundary conditions. The finite-element structural analysis method was used to study the effects of plate boundary conditions, plate aspect ratio, hole size, and the composite stacking sequence on the compressive buckling strengths of the perforated MMC plates. Studies show that by increasing the hole sizes, compressive buckling strengths of the perforated MMC plates could be considerably increased under certain boundary conditions and aspect ratios ("anomalous" buckling behavior); and that the plate buckling mode could be symmetrical or antisymmetrical, depending on the plate boundary conditions, aspect ratio, and the hole size. For same-sized plates with same-sized holes, the compressive buckling strengths of the perforated MMC plates with [90/0/0/90]2 lamination could be as much as 10 percent higher or lower than those of the [45/- 45/- 45/45]2 laminations, depending on the plate boundary conditions, plate aspect ratios, and the hole size. Clamping the plate edges induces far stronger "anomalous" buckling behavior (enhancing compressive buckling strengths at increasing hole sizes) of the perforated MMC plates than simply supporting the plate edges.

Study of imaging plate detector sensitivity to 5-18 MeV electrons

NASA Astrophysics Data System (ADS)

Boutoux, G.; Rabhi, N.; Batani, D.; Binet, A.; Ducret, J.-E.; Jakubowska, K.; Nègre, J.-P.; Reverdin, C.; Thfoin, I.

2015-11-01

Imaging plates (IPs) are commonly used as passive detectors in laser-plasma experiments. We calibrated at the ELSA electron beam facility (CEA DIF) the five different available types of IPs (namely, MS-SR-TR-MP-ND) to electrons from 5 to 18 MeV. In the context of diagnostic development for the PETawatt Aquitaine Laser (PETAL), we investigated the use of stacks of IP in order to increase the detection efficiency and get detection response independent from the neighboring materials such as X-ray shielding and detector supports. We also measured fading functions in the time range from a few minutes up to a few days. Finally, our results are systematically compared to GEANT4 simulations in order to provide a complete study of the IP response to electrons over the energy range relevant for PETAL experiments.

Development of a method for efficient cost-effective screening of Aspergillus niger mutants having increased production of glucoamylase.

PubMed

Zhu, Xudong; Arman, Bessembayev; Chu, Ju; Wang, Yonghong; Zhuang, Yingping

2017-05-01

To develop an efficient cost-effective screening process to improve production of glucoamylase in Aspergillus niger. The cultivation of A. niger was achieved with well-dispersed morphology in 48-deep-well microtiter plates, which increased the throughput of the samples compared to traditional flask cultivation. There was a close negative correlation between glucoamylase and its pH of the fermentation broth. A novel high-throughput analysis method using Methyl Orange was developed. When compared to the conventional analysis method using 4-nitrophenyl α-D-glucopyranoside as substrate, a correlation coefficient of 0.96 by statistical analysis was obtained. Using this novel screening method, we acquired a strain with an activity of 2.2 × 10 3  U ml -1 , a 70% higher yield of glucoamylase than its parent strain.

Turbulence convective heat transfer for cooling the photovoltaic cells

NASA Astrophysics Data System (ADS)

Arianmehr, Iman

Solar PV (photovoltaic) is a rapidly advancing renewable energy technology which converts sunlight directly into electricity. One of the outstanding challenges of the current PV technology is the reduction in its conversion efficiency with increasing PV panel temperature, which is closely associated with the increase in solar intensity and the ambient temperature surrounding the PV panels. To more effectively capture the available energy when the sun is most intense, significant efforts have been invested in active and passive cooling research over the last few years. While integrated cooling systems can lead to the highest total efficiencies, they are usually neither the most feasible nor the most cost effective solutions. This work examines some simple passive means of manipulating the prevailing wind turbulence to enhance convective heat transfer over a heated plate in a wind tunnel.

S-F graphic representation analysis of photoelectric facula focometer poroo-plate glass

NASA Astrophysics Data System (ADS)

Tong, Yilin; Han, Xuecai

2016-10-01

Optical system focal length is usually based on the magnification method with focal length measurement poroo-plate glass is used as base element measuring focal length of focometer. On the basis of using analysis of magnification method to measure the accuracy of optical lens focal length, an expression between the ruling span of poroo-plate glass and the focal length of measured optical system was deduced, an efficient method to work out S-F graph with AUTOCAD was developed, the selecting principle of focometer parameter was analyzed, and Applied examples for designing poroo-plate glass in S-F figure was obtained.

Distributed coupling high efficiency linear accelerator

DOEpatents

Tantawi, Sami G.; Neilson, Jeffrey

2016-07-19

A microwave circuit for a linear accelerator includes multiple monolithic metallic cell plates stacked upon each other so that the beam axis passes vertically through a central acceleration cavity of each plate. Each plate has a directional coupler with coupling arms. A first coupling slot couples the directional coupler to an adjacent directional coupler of an adjacent cell plate, and a second coupling slot couples the directional coupler to the central acceleration cavity. Each directional coupler also has an iris protrusion spaced from corners joining the arms, a convex rounded corner at a first corner joining the arms, and a corner protrusion at a second corner joining the arms.

Investigation on filter method for smoothing spiral phase plate

NASA Astrophysics Data System (ADS)

Zhang, Yuanhang; Wen, Shenglin; Luo, Zijian; Tang, Caixue; Yan, Hao; Yang, Chunlin; Liu, Mincai; Zhang, Qinghua; Wang, Jian

2018-03-01

Spiral phase plate (SPP) for generating vortex hollow beams has high efficiency in various applications. However, it is difficult to obtain an ideal spiral phase plate because of its continuous-varying helical phase and discontinued phase step. This paper describes the demonstration of continuous spiral phase plate using filter methods. The numerical simulations indicate that different filter method including spatial domain filter, frequency domain filter has unique impact on surface topography of SPP and optical vortex characteristics. The experimental results reveal that the spatial Gaussian filter method for smoothing SPP is suitable for Computer Controlled Optical Surfacing (CCOS) technique and obtains good optical properties.

Extended plate and beam demonstration home

Treesearch

Patricia Gunderson; Vladimir Kochkin; Xiping Wang

2018-01-01

An extended plate and beam (EP&B) design was developed at Home Innovation Research Labs (Upper Marlboro, Maryland) in an effort to provide traditional light-frame wall construction details that are compatible with continuous insulating sheathing. This would encourage wide-spread adoption of high-R walls and promote greater energy efficiency in new houses. The...

Grooved Armor Plate

DTIC Science & Technology

1935-05-16

that many of the olateo tested do sux^ ass the reouired limita by a considerable margin. Therefore, the efficiency of these grooved plate...Plpte Thicknesn B>lll<tle .Llji^f - ./.. s... a’ ^ea:: of All RtSUltS !’ Teen of Rlgbeot lOf of All Reoultr. s/i«- 1830 an« 7/16" ?180

49 CFR 179.300-6 - Thickness of plates.

Code of Federal Regulations, 2010 CFR

2010-10-01

....037 Where: d = inside diameter in inches; E = 1.0 welded joint efficiency; P = minimum required bursting pressure in psig; S = minimum tensile strength of plate material in p.s.i. as prescribed in § 179... −d 2) where: d = inside diameter in inches; D = outside diameter in inches; p = tank test pressure in...

Development of Si-APD Timing Detectors for Nuclear Resonant Scattering using High-energy Synchrotron X-rays

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

Kishimoto, Shunji; Zhang Xiaowei; Yoda, Yoshitaka

2007-01-19

A timing detector with silicon avalanche photodiodes (Si-APDs) has been developed for nuclear resonant scattering using synchrotron x-rays. The detector had four pairs of a germanium plate 0.1mm thick and a Si-APD (3 mm in dia., a depletion layer of 30-{mu}m thickness). Using synchrotron x-rays of 67.4 keV, the efficiency increased to 1.5% for the incident beam, while the efficiency was 0.76 % without the germanium converters. A measurement of SR-PAC on Ni-61 was executed by using the detector. Some other types of timing detectors are planned for x-rays of E>20 keV.

Review of the Potential of the Ni/Cu Plating Technique for Crystalline Silicon Solar Cells

PubMed Central

Rehman, Atteq ur; Lee, Soo Hong

2014-01-01

Developing a better method for the metallization of silicon solar cells is integral part of realizing superior efficiency. Currently, contact realization using screen printing is the leading technology in the silicon based photovoltaic industry, as it is simple and fast. However, the problem with metallization of this kind is that it has a lower aspect ratio and higher contact resistance, which limits solar cell efficiency. The mounting cost of silver pastes and decreasing silicon wafer thicknesses encourages silicon solar cell manufacturers to develop fresh metallization techniques involving a lower quantity of silver usage and not relying pressing process of screen printing. In recent times nickel/copper (Ni/Cu) based metal plating has emerged as a metallization method that may solve these issues. This paper offers a detailed review and understanding of a Ni/Cu based plating technique for silicon solar cells. The formation of a Ni seed layer by adopting various deposition techniques and a Cu conducting layer using a light induced plating (LIP) process are appraised. Unlike screen-printed metallization, a step involving patterning is crucial for opening the masking layer. Consequently, experimental procedures involving patterning methods are also explicated. Lastly, the issues of adhesion, back ground plating, process complexity and reliability for industrial applications are also addressed. PMID:28788516

Review of the Potential of the Ni/Cu Plating Technique for Crystalline Silicon Solar Cells.

PubMed

Rehman, Atteq Ur; Lee, Soo Hong

2014-02-18

Developing a better method for the metallization of silicon solar cells is integral part of realizing superior efficiency. Currently, contact realization using screen printing is the leading technology in the silicon based photovoltaic industry, as it is simple and fast. However, the problem with metallization of this kind is that it has a lower aspect ratio and higher contact resistance, which limits solar cell efficiency. The mounting cost of silver pastes and decreasing silicon wafer thicknesses encourages silicon solar cell manufacturers to develop fresh metallization techniques involving a lower quantity of silver usage and not relying pressing process of screen printing. In recent times nickel/copper (Ni/Cu) based metal plating has emerged as a metallization method that may solve these issues. This paper offers a detailed review and understanding of a Ni/Cu based plating technique for silicon solar cells. The formation of a Ni seed layer by adopting various deposition techniques and a Cu conducting layer using a light induced plating (LIP) process are appraised. Unlike screen-printed metallization, a step involving patterning is crucial for opening the masking layer. Consequently, experimental procedures involving patterning methods are also explicated. Lastly, the issues of adhesion, back ground plating, process complexity and reliability for industrial applications are also addressed.

Leptin stimulates aromatase in the growth plate: limiting catch-up growth efficiency.

PubMed

Masarwi, Majdi; Shamir, Raanan; Phillip, Moshe; Gat-Yablonski, Galia

2018-06-01

Catch-up growth (CUG) in childhood is defined as periods of growth acceleration, after the resolution of growth attenuation causes, bringing the children back to their original growth trajectory. Sometimes, however, CUG is incomplete, leading to permanent growth deficit and short stature. The aim of this study was to investigate the mechanisms that limit nutritional-CUG. Specifically, we focused on the crosstalk between leptin, increased by re-feeding, and sex hormones, which increase with age. In vivo studies were performed in young male Sprague Dawley rats fed ad libitum or subjected to 10/36 days of 40% food restriction followed by 90-120 days of re-feeding. In vitro studies were performed on ATDC5 cells. Analyses of mRNA and protein levels were done using qPCR and Western blot, respectively. CUG was complete in body weight and humerus length in animals that were food-restricted for 10 days but not for those food-restricted for 36 days. In vitro studies showed that leptin significantly increased aromatase gene expression and protein level as well as the expression of estrogen and leptin receptors in a dose- and time-dependent manner. The effect of leptin on aromatase was direct and was mediated through the MAPK/Erk, STAT3 and PI3K pathways. The crosstalk between leptin and aromatase in the growth plate suggests that re-feeding during puberty may lead to increased estrogen level and activity, and consequently, irreversible premature epiphyseal growth plate closure. These results may have important implications for the development of novel treatment strategies for short stature in children. © 2018 Society for Endocrinology.

Efficiency of dual-cured resin cement polymerization induced by high-intensity LED curing units through ceramic material.

PubMed

Watanabe, H; Kazama, Re; Asai, T; Kanaya, F; Ishizaki, H; Fukushima, M; Okiji, T

2015-01-01

This study aimed to evaluate the ability of high-intensity light-emitting diode (LED) and other curing units to cure dual-cured resin cement through ceramic material. A halogen curing unit (Jetlite 3000, Morita), a second-generation LED curing unit (Demi, Kerr), and two high-intensity LED curing units (PenCure 2000, Morita; Valo, Ultradent) were tested. Feldspathic ceramic plates (VITABLOCS Mark II, A3; Vita Zahnfabrik) with thicknesses of 1.0, 2.0, and 3.0 mm were prepared. Dual-cured resin cement samples (Clearfil Esthetic Cement, Kuraray Noritake Dental) were irradiated directly or through one of the ceramic plates for different periods (5, 10, 15, or 20 seconds for the high-intensity LED units and 20, 40, 60, or 80 seconds for the others). The Knoop hardness test was used to determine the level of photopolymerization that had been induced in the resin cement. Data were analyzed by one-way analysis of variance and Dunnett's post-hoc test to identify test-control (maximum irradiation without a ceramic plate) differences for each curing unit (p<0.05). For all curing units, the curing conditions had a statistically significant effect on the Knoop hardness numbers (KHNs) of the irradiated cement samples (p<0.001). In general, the KHN decreased with increasing plate thickness and increased as the irradiation period was extended. Jetlite 3000 achieved control-level KHN values only when the plate thickness was 1.0 mm. At a plate thickness ≥2.0 mm, the LED units (except for PenCure 2000 at 3.0 mm) were able to achieve control-level KHN values when the irradiation time was extended. At a plate thickness of 3.0 mm, irradiation for 20 seconds with the Valo or for 80 seconds with the Demi were the only methods that produced KHN values equivalent to those produced by direct irradiation. Regardless of the type of curing unit used, indirect irradiation of dual-cured resin cement through a ceramic plate resulted in decreased KHN values compared with direct irradiation. When the irradiation period was extended, only the LED units were able to achieve similar KHN values to those observed under direct irradiation in the presence of plates ≥2.0-mm thick. High-intensity LED units require a shorter irradiation period than halogen and second-generation LED curing units to obtain KHN values similar to those observed during direct irradiation.

An efficient low frequency horizontal diamagnetic levitation mechanism based vibration energy harvester

NASA Astrophysics Data System (ADS)

Palagummi, S.; Yuan, F. G.

2016-04-01

This article identifies and studies key parameters that characterize a horizontal diamagnetic levitation (HDL) mechanism based low frequency vibration energy harvester with the aim of enhancing performance metrics such as efficiency and volume figure of merit (FoMv). The HDL mechanism comprises of three permanent magnets and two diamagnetic plates. Two of the magnets, aka lifting magnets, are placed co-axially at a distance such that each attract a centrally located magnet, aka floating magnet, to balance its weight. This floating magnet is flanked closely by two diamagnetic plates which stabilize the levitation in the axial direction. The influence of the geometry of the floating magnet, the lifting magnet and the diamagnetic plate are parametrically studied to quantify their effects on the size, stability of the levitation mechanism and the resonant frequency of the floating magnet. For vibration energy harvesting using the HDL mechanism, a coil geometry and eddy current damping are critically discussed. Based on the analysis, an efficient experimental system is setup which showed a softening frequency response with an average system efficiency of 25.8% and a FoMv of 0.23% when excited at a root mean square acceleration of 0.0546 m/s2 and at frequency of 1.9 Hz.

NSTX Disruption Simulations of Detailed Divertor and Passive Plate Models by Vector Potential Transfer from OPERA Global Analysis Results

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

P. H. Titus, S. Avasaralla, A.Brooks, R. Hatcher

2010-09-22

The National Spherical Torus Experiment (NSTX) project is planning upgrades to the toroidal field, plasma current and pulse length. This involves the replacement of the center-stack, including the inner legs of the TF, OH, and inner PF coils. A second neutral beam will also be added. The increased performance of the upgrade requires qualification of the remaining components including the vessel, passive plates, and divertor for higher disruption loads. The hardware needing qualification is more complex than is typically accessible by large scale electromagnetic (EM) simulations of the plasma disruptions. The usual method is to include simplified representations of componentsmore » in the large EM models and attempt to extract forces to apply to more detailed models. This paper describes a more efficient approach of combining comprehensive modeling of the plasma and tokamak conducting structures, using the 2D OPERA code, with much more detailed treatment of individual components using ANSYS electromagnetic (EM) and mechanical analysis. This capture local eddy currents and resulting loads in complex details, and allows efficient non-linear, and dynamic structural analyses.« less

Optomechanical study and optimization of cantilever plate dynamics

NASA Astrophysics Data System (ADS)

Furlong, Cosme; Pryputniewicz, Ryszard J.

1995-06-01

Optimum dynamic characteristics of an aluminum cantilever plate containing holes of different sizes and located at arbitrary positions on the plate are studied computationally and experimentally. The objective function of this optimization is the minimization/maximization of the natural frequencies of the plate in terms of such design variable s as the sizes and locations of the holes. The optimization process is performed using the finite element method and mathematical programming techniques in order to obtain the natural frequencies and the optimum conditions of the plate, respectively. The modal behavior of the resultant optimal plate layout is studied experimentally through the use of holographic interferometry techniques. Comparisons of the computational and experimental results show that good agreement between theory and test is obtained. The comparisons also show that the combined, or hybrid use of experimental and computational techniques complement each other and prove to be a very efficient tool for performing optimization studies of mechanical components.

A probabilistic approach towards understanding how planet composition affects plate tectonics - through time and space.

NASA Astrophysics Data System (ADS)

Stamenkovic, V.

2017-12-01

We focus on the connections between plate tectonics and planet composition — by studying how plate yielding is affected by surface and mantle water, and by variable amounts of Fe, SiC, or radiogenic heat sources within the planet interior. We especially explore whether we can make any robust conclusions if we account for variable initial conditions, current uncertainties in model parameters and the pressure dependence of the viscosity, as well as uncertainties on how a variable composition affects mantle rheology, melting temperatures, and thermal conductivities. We use a 1D thermal evolution model to explore with more than 200,000 simulations the robustness of our results and use our previous results from 3D calculations to help determine the most likely scenario within the uncertainties we still face today. The results that are robust in spite of all uncertainties are that iron-rich mantle rock seems to reduce the efficiency of plate yielding occurring on silicate planets like the Earth if those planets formed along or above mantle solidus and that carbon planets do not seem to be ideal candidates for plate tectonics because of slower creep rates and generally higher thermal conductivities for SiC. All other conclusions depend on not yet sufficiently constrained parameters. For the most likely case based on our current understanding, we find that, within our range of varied planet conditions (1-10 Earth masses), planets with the greatest efficiency of plate yielding are silicate rocky planets of 1 Earth mass with large metallic cores (average density 5500-7000 kg m-3) with minimal mantle concentrations of iron (as little as 0% is preferred) and radiogenic isotopes at formation (up to 10 times less than Earth's initial abundance; less heat sources do not mean no heat sources). Based on current planet formation scenarios and observations of stellar abundances across the Galaxy as well as models of the evolution of the interstellar medium, such planets are suggested to be statistically more common around young stars in the outer disk of the Milky Way. Rocky super-Earths, undifferentiated planets, and still hypothetical carbon planets have the lowest plate yielding efficiencies found in our study. This work aids exoplanet characterization and helps explore the fundamental drivers of plate tectonics.

Numerical modeling for an electric-field hyperthermia applicator

NASA Technical Reports Server (NTRS)

Wu, Te-Kao; Chou, C. K.; Chan, K. W.; Mcdougall, J.

1993-01-01

Hyperthermia, in conjunction with radiation and chemotherapy for treatment of cancers, is an area of current concern. Experiments have shown that hyperthermia can increase the potency of many chemotherapy drugs and the effectiveness of radiation for treating cancer. A combination of whole body or regional hyperthermia with chemotherapy or radiation should improve treatment results. Conventional methods for inducing whole body hyperthermia, such as exposing a patient in a radiant cabinet or under a hot water blanket, conduct heat very slowly from the skin to the body core. Thus a more efficient system, such as the three-plate electric-field hyperthermia applicator (EHA), is developed. This three-plate EHA has one top plate over and two lower plates beneath the patient. It is driven at 27.12 MHz with 500 Watts through a matching circuit. Using this applicator, a 50 kg pig was successfully heated to 42 C within 45 minutes. However, phantom and animal studies have indicated non-uniform heating near the side of the body. In addition, changes in the size and distance between the electrode plates can affect the heating (or electromagnetic field) pattern. Therefore, numerical models using the method of moments (MOM) or the finite difference time domain (FDTD) technique are developed to optimize the heating pattern of this EHA before it is used for human trials. The accuracy of the numerical modeling has been achieved by the good agreement between the MOM and FDTD results for the three-plate EHA without a biological body. The versatile FDTD technique is then applied to optimize the EHA design with a human body. Both the numerical and measured data in phantom blocks will be presented. The results of this study will be used to design an optimized system for whole body or regional hyperthermia.

Time variability in Cenozoic reconstructions of mantle heat flow: plate tectonic cycles and implications for Earth's thermal evolution.

PubMed

Loyd, S J; Becker, T W; Conrad, C P; Lithgow-Bertelloni, C; Corsetti, F A

2007-09-04

The thermal evolution of Earth is governed by the rate of secular cooling and the amount of radiogenic heating. If mantle heat sources are known, surface heat flow at different times may be used to deduce the efficiency of convective cooling and ultimately the temporal character of plate tectonics. We estimate global heat flow from 65 Ma to the present using seafloor age reconstructions and a modified half-space cooling model, and we find that heat flow has decreased by approximately 0.15% every million years during the Cenozoic. By examining geometric trends in plate reconstructions since 120 Ma, we show that the reduction in heat flow is due to a decrease in the area of ridge-proximal oceanic crust. Even accounting for uncertainties in plate reconstructions, the rate of heat flow decrease is an order of magnitude faster than estimates based on smooth, parameterized cooling models. This implies that heat flow experiences short-term fluctuations associated with plate tectonic cyclicity. Continental separation does not appear to directly control convective wavelengths, but rather indirectly affects how oceanic plate systems adjust to accommodate global heat transport. Given that today's heat flow may be unusually low, secular cooling rates estimated from present-day values will tend to underestimate the average cooling rate. Thus, a mechanism that causes less efficient tectonic heat transport at higher temperatures may be required to prevent an unreasonably hot mantle in the recent past.

Time variability in Cenozoic reconstructions of mantle heat flow: Plate tectonic cycles and implications for Earth's thermal evolution

PubMed Central

Loyd, S. J.; Becker, T. W.; Conrad, C. P.; Lithgow-Bertelloni, C.; Corsetti, F. A.

2007-01-01

The thermal evolution of Earth is governed by the rate of secular cooling and the amount of radiogenic heating. If mantle heat sources are known, surface heat flow at different times may be used to deduce the efficiency of convective cooling and ultimately the temporal character of plate tectonics. We estimate global heat flow from 65 Ma to the present using seafloor age reconstructions and a modified half-space cooling model, and we find that heat flow has decreased by ∼0.15% every million years during the Cenozoic. By examining geometric trends in plate reconstructions since 120 Ma, we show that the reduction in heat flow is due to a decrease in the area of ridge-proximal oceanic crust. Even accounting for uncertainties in plate reconstructions, the rate of heat flow decrease is an order of magnitude faster than estimates based on smooth, parameterized cooling models. This implies that heat flow experiences short-term fluctuations associated with plate tectonic cyclicity. Continental separation does not appear to directly control convective wavelengths, but rather indirectly affects how oceanic plate systems adjust to accommodate global heat transport. Given that today's heat flow may be unusually low, secular cooling rates estimated from present-day values will tend to underestimate the average cooling rate. Thus, a mechanism that causes less efficient tectonic heat transport at higher temperatures may be required to prevent an unreasonably hot mantle in the recent past. PMID:17720806

Gamma-ray detection efficiency of the microchannel plate installed as an ion detector in the low energy particle instrument onboard the GEOTAIL satellite.

PubMed

Tanaka, Y T; Yoshikawa, I; Yoshioka, K; Terasawa, T; Saito, Y; Mukai, T

2007-03-01

A microchannel plate (MCP) assembly has been used as an ion detector in the low energy particle (LEP) instrument onboard the magnetospheric satellite GEOTAIL. Recently the MCP assembly has detected gamma rays emitted from an astronomical object and has been shown to provide unique information of gamma rays if they are intense enough. However, the detection efficiency for gamma rays was not measured before launch, and therefore we could not analyze the LEP data quantitatively. In this article, we report the gamma-ray detection efficiency of the MCP assembly. The measured efficiencies are 1.29%+/-0.71% and 0.21%+/-0.14% for normal incidence 60 and 662 keV gamma rays, respectively. The incident angle dependence is also presented. Our calibration is crucial to study high energy astrophysical phenomena by using the LEP.

Field programmable gate arrays-based number plate binarization and adjustment for automatic number plate recognition systems

NASA Astrophysics Data System (ADS)

Zhai, Xiaojun; Bensaali, Faycal; Sotudeh, Reza

2013-01-01

Number plate (NP) binarization and adjustment are important preprocessing stages in automatic number plate recognition (ANPR) systems and are used to link the number plate localization (NPL) and character segmentation stages. Successfully linking these two stages will improve the performance of the entire ANPR system. We present two optimized low-complexity NP binarization and adjustment algorithms. Efficient area/speed architectures based on the proposed algorithms are also presented and have been successfully implemented and tested using the Mentor Graphics RC240 FPGA development board, which together require only 9% of the available on-chip resources of a Virtex-4 FPGA, run with a maximum frequency of 95.8 MHz and are capable of processing one image in 0.07 to 0.17 ms.

Effects of cutouts on the behavior of symmetric composite laminates subjected to bending and twisting loads

NASA Technical Reports Server (NTRS)

Prasad, C. B.; Shuart, M. J.; Bains, N. J.; Rouse, M.

1993-01-01

Composite structures are used for a wide variety of aerospace applications. Practical structures contain cutouts and these structures are subjected to in-plane and out-of-plane loading conditions. Structurally efficient designs for composite structures require a thorough understanding of the effects of cutouts on the response of composite plates subjected to inplane or out-of-plane loadings. Most investigations of the behavior of composite plates with cutouts have considered in-plane loadings only. Out-of-plane loadings suchas bending or twisting have received very limited attention. The response of homogeneous plates (e.g., isotropic or orthotropic plates) subjected to bending or twisting moments has been studied analytically. These analyses are for infinite plates and neglect finite-plate effects. Recently, analytical and experimental studies were conducted to determine the effects of cutouts on the response of laminated composite plates subjected to bending moments. No analytical or experimental results are currently available for the effects of cutouts on the response of composite laminates subjected to twisting moments.

Heat adaptation of bioabsorbable craniofacial plates: a critical review of science and technology.

PubMed

Pietrzak, William S

2009-11-01

Bioabsorbable fixation plates often require adaptation to the bone. This is typically accomplished by heating the plates to above the glass transition temperature and placing the softened plates against the bone or a prebent template until cool. Upon cooling, the plates regain stiffness and can be attached to bone to obtain anatomic fixation. This procedure is both efficient and effective and has been used throughout the craniofacial skeleton. There are many types of equipment available to heat the plates, each with advantages and disadvantages. Although a conceptually simple process, there are several nuances that have been reported in the literature, including transient effects on plate mechanical properties, memory effects, differences between wet and dry heating, and others. Upon the backdrop of the overwhelming clinical success of heat adaptation, this review critically evaluates the method and provides a comprehensive examination and explanation of the basic science and technology involved. This should help give surgeons a better understanding of the process that can help improve their use and further advance the technology.

The effect of zinc (Zn) content to cell potential value and efficiency aluminium sacrificial anode in 0.2 M sulphuric acid environment

NASA Astrophysics Data System (ADS)

Akranata, Ahmad Ridho; Sulistijono, Awali, Jatmoko

2018-04-01

Sacrificial anode is sacirifial component that used to protect steel from corrosion. Generally, the component are made of aluminium and zinc in water environment. Sacrificial anode change the protected metal structure become cathodic with giving current. The advantages of aluminium is corrosion resistance, non toxicity and easy forming. Zinc generally used for coating in steel to prevent steel from corrosion. This research was conducted to analyze the effect of zinc content to the value of cell potential and efficiency aluminium sacrificial anode with sand casting method in 0.2 M sulphuric acid environment. The sacrificial anode fabrication made with alloying aluminium and zinc metals with variation composition of alloy with pure Al, Al-3Zn, Al-6Zn, and Al-9Zn with open die sand casting process. The component installed with ASTM A36 steel. After the research has been done the result showed that addition of zinc content increase the cell potential, protection efficiency, and anode efficiency from steel plate. Cell potential value measurement and weight loss measurement showed that addition of zinc content increase the cell potential value into more positive that can protected the ASTM A36 steel more efficiently that showed in weight loss measurement where the protection efficiency and anodic efficiency of Al-9Zn sacrificial anode is better than protection efficiency and anodic efficiency of pure Al. The highest protection efficiency gotten by Al-9Zn alloy

Effects of electrode gap and electric current on chlorine generation of electrolyzed deep ocean water.

PubMed

Hsu, Guoo-Shyng Wang; Hsu, Shun-Yao

2018-04-01

Electrolyzed water is a sustainable disinfectant, which can comply with food safety regulations and is environmental friendly. A two-factor central composite design was adopted for studying the effects of electrode gap and electric current on chlorine generation efficiency of electrolyzed deep ocean water. Deep ocean water was electrolyzed in a glass electrolyzing cell equipped with platinum-plated titanium anode and cathode in a constant-current operation mode. Results showed that current density, chlorine concentration, and electrolyte temperature increased with electric current, while electric efficiency decreased with electric current and electrode gap. An electrode gap of less than 11.7 mm, and a low electric current appeared to be a more energy efficient design and operation condition for the electrolysis system. Copyright © 2017. Published by Elsevier B.V.

Study on the CO2 electric driven fixed swash plate type compressor for eco-friendly vehicles

NASA Astrophysics Data System (ADS)

Nam, Donglim; Kim, Kitae; Lee, Jehie; Kwon, Yunki; Lee, Geonho

2017-08-01

The purpose of this study is to experiment and to performance analysis about the electric-driven fixed swash plate compressor using alternate refrigerant(R744). Comprehensive simulation model for an electric driven compressor using CO2 for eco-friendly vehicle is presented. This model consists of compression model and dynamic model. The compression model included valve dynamics, leakage, and heat transfer models. And the dynamic model included frictional loss between piston ring and cylinder wall, frictional loss between shoe and swash plate, frictional loss of bearings, and electric efficiency. Especially, because the efficiency of an electric parts(motor and inverter) in the compressor affects the loss of the compressor, the dynamo test was performed. We made the designed compressor, and tested the performance of the compressor about the variety pressure conditions. Also we compared the performance analysis result and performance test result.

Comparison under a simulated sun of two black-nickel-coated flat-plate solar collectors with a nonselective black-paint-coated collector

NASA Technical Reports Server (NTRS)

Simon, F. F.

1975-01-01

A performance evaluation was made of two, black nickel coated, flat plate solar collectors. Collector performance was determined under a simulated sun for a wide range of inlet temperatures, including the temperature required for solar powered absorption air conditioning. For a basis of comparison a performance test was made on a traditional, two glass, nonselective, black paint coated, flat plate collector. Performance curves and performance parameters are presented to point out the importance of the design variables which determine an efficient collector. A black nickel coated collector was found to be a good performer at the conditions expected for solar powered absorption air conditioning. This collector attained a thermal efficiency of 50 percent at an inlet temperature of 366 K (200 F) and an incident flux of 946 watts/sq m (300 Btu/hr-sq ft).

Solar photochemical process engineering for production of fuels and chemicals

NASA Technical Reports Server (NTRS)

Biddle, J. R.; Peterson, D. B.; Fujita, T.

1984-01-01

The engineering costs and performance of a nominal 25,000 scmd (883,000 scfd) photochemical plant to produce dihydrogen from water were studied. Two systems were considered, one based on flat-plate collector/reactors and the other on linear parabolic troughs. Engineering subsystems were specified including the collector/reactor, support hardware, field transport piping, gas compression equipment, and balance-of-plant (BOP) items. Overall plant efficiencies of 10.3 and 11.6% are estimated for the flat-plate and trough systems, respectively, based on assumed solar photochemical efficiencies of 12.9 and 14.6%. Because of the opposing effects of concentration ratio and operating temperature on efficiency, it was concluded that reactor cooling would be necessary with the trough system. Both active and passive cooling methods were considered. Capital costs and energy costs, for both concentrating and non-concentrating systems, were determined and their sensitivity to efficiency and economic parameters were analyzed. The overall plant efficiency is the single most important factor in determining the cost of the fuel.

Solar photochemical process engineering for production of fuels and chemicals

NASA Technical Reports Server (NTRS)

Biddle, J. R.; Peterson, D. B.; Fujita, T.

1985-01-01

The engineering costs and performance of a nominal 25,000 scmd (883,000 scfd) photochemical plant to produce dihydrogen from water were studied. Two systems were considered, one based on flat-plate collector/reactors and the other on linear parabolic troughs. Engineering subsystems were specified including the collector/reactor, support hardware, field transport piping, gas compression equipment, and balance-of-plant (BOP) items. Overall plant efficiencies of 10.3 and 11.6 percent are estimated for the flat-plate and trough systems, respectively, based on assumed solar photochemical efficiencies of 12.9 and 14.6 percent. Because of the opposing effects of concentration ratio and operating temperature on efficiency, it was concluded that reactor cooling would be necessary with the trough system. Both active and passive cooling methods were considered. Capital costs and energy costs, for both concentrating and non-concentrating systems, were determined and their sensitivity to efficiency and economic parameters were analyzed. The overall plant efficiency is the single most important factor in determining the cost of the fuel.

Maximizing the quantum efficiency of microchannel plate detectors - The collection of photoelectrons from the interchannel web using an electric field

NASA Technical Reports Server (NTRS)

Taylor, R. C.; Hettrick, M. C.; Malina, R. F.

1983-01-01

High quantum efficiency and two-dimensional imaging capabilities make the microchannel plate (MCP) a suitable detector for a sky survey instrument. The Extreme Ultraviolet Explorer satellite, to be launched in 1987, will use MCP detectors. A feature which limits MCP efficiency is related to the walls of individual channels. The walls are of finite thickness and thus form an interchannel web. Under normal circumstances, this web does not contribute to the detector's quantum efficiency. Panitz and Foesch (1976) have found that in the case of a bombardment with ions, electrons were ejected from the electrode material coating the web. By applying a small electric field, the electrons were returned to the MCP surface where they were detected. The present investigation is concerned with the enhancement of quantum efficiencies in the case of extreme UV wavelengths. Attention is given to a model and a computer simulation which quantitatively reproduce the experimental results.

Whole Planet Coupling from Climate to Core: Implications for the Evolution of Rocky Planets and their Prospects for Habitability

NASA Astrophysics Data System (ADS)

Foley, B. J.; Driscoll, P. E.

2015-12-01

Many factors have conspired to make Earth a home to complex life. Earth has abundant water due to a combination of factors, including orbital distance and the climate regulating feedbacks of the long-term carbon cycle. Earth has plate tectonics, which is crucial for maintaining long-term carbon cycling and may have been an important energy source for the origin of life in seafloor hydrothermal systems. Earth also has a strong magnetic field that shields the atmosphere from the solar wind and the surface from high-energy particles. Synthesizing recent work on these topics shows that water, a temperate climate, plate tectonics, and a strong magnetic field are linked together through a series of negative feedbacks that stabilize the system over geologic timescales. Although the physical mechanism behind plate tectonics on Earth is still poorly understood, climate is thought to be important. In particular, temperate surface temperatures are likely necessary for plate tectonics because they allow for liquid water that may be capable of significantly lowering lithospheric strength, increase convective stresses in the lithosphere, and enhance the effectiveness of "damage" processes such as grainsize reduction. Likewise, plate tectonics is probably crucial for maintaining a temperate climate on Earth through its role in facilitating the long-term carbon cycle, which regulates atmospheric CO2 levels. Therefore, the coupling between plate tectonics and climate is a feedback that is likely of first order importance for the evolution of rocky planets. Finally, plate tectonics is thought to be important for driving the geodynamo. Plate tectonics efficiently cools the mantle, leading to vigorous thermo-chemical convection in the outer core and dynamo action; without plate tectonics inefficient mantle cooling beneath a stagnant lid may prevent a long-lived magnetic field. As the magnetic field shields a planet's atmosphere from the solar wind, the magnetic field may be important for preserving hydrogen, and therefore water, on the surface. Thus whole planet coupling between the magnetic field, atmosphere, mantle, and core is possible. We lay out the basic physics governing whole planet coupling, and discuss the implications this coupling has for the evolution of rocky planets and their prospects for hosting life.

Time reversal focusing of elastic waves in plates for an educational demonstration.

PubMed

Heaton, Christopher; Anderson, Brian E; Young, Sarah M

2017-02-01

The purpose of this research is to develop a visual demonstration of time reversal focusing of vibrations in a thin plate. Various plate materials are tested to provide optimal conditions for time reversal focusing. Specifically, the reverberation time in each plate and the vibration coupling efficiency from a shaker to the plate are quantified to illustrate why a given plate provides the best spatially confined focus as well as the highest focal amplitude possible. A single vibration speaker and a scanning laser Doppler vibrometer (SLDV) are used to provide the time reversal focusing. Table salt is sprinkled onto the plate surface to allow visualization of the high amplitude, spatially localized time reversal focus; the salt is thrown upward only at the focal position. Spatial mapping of the vibration focusing on the plate using the SLDV is correlated to the visual salt jumping demonstration. The time reversal focusing is also used to knock over an object when the object is placed at the focal position; some discussion of optimal objects to use for this demonstration are given.

A compact and high efficiency GAGG well counter for radiocesium concentration measurements

NASA Astrophysics Data System (ADS)

Yamamoto, Seiichi; Ogata, Yoshimune

2014-07-01

After the Fukushima nuclear disaster, social concern about radiocesium (137Cs and 134Cs) contamination in food increased. However, highly efficient instruments that can measure low level radioactivity are quite expensive and heavy. A compact, lightweight, and reliable radiation detector that can inexpensively monitor low level radiocesium is highly desired. We developed a compact and highly efficient radiocesium detector to detect ~32 keV X-rays from radiocesium instead of high energy gamma photons. A 1-mm thick GAGG scintillator was selected to effectively detect ~32 keV X-rays from 137Cs to reduce the influence of ambient radiation. Four sets of 25 mm×25 mm×1 mm GAGG plates, each of which was optically coupled to a triangular-shaped light guide, were optically coupled to a photomultiplier tube (PMT) to form a square-shaped well counter. Another GAGG plate was directly optically coupled to the PMT to form its bottom detector. The energy resolution of the GAGG well counter was 22.3% FWHM for 122 keV gamma rays and 32% FWHM for ~32 keV X-rays. The counting efficiency for the X-rays from radiocesium (mixture of 137Cs and 134Cs) was 4.5%. In measurements of the low level radiocesium mixture, a photo-peak of ~32 keV X-rays can clearly be distinguished from the background. The minimum detectable activity (MDA) was estimated to be ~100 Bq/kg for 1000 s measurement. The results show that our developed GAGG well counter is promising for the detection of radiocesium in food.

Attenuation of laser radiation by the flame of burning hydrocarbons and efficiency of remote cutting of metals

NASA Astrophysics Data System (ADS)

Gvozdev, S. V.; Glova, A. F.; Dubrovskii, V. Yu; Durmanov, S. T.; Krasyukov, A. G.; Lysikov, A. Yu; Smirnov, G. V.; Pleshkov, V. M.

2017-12-01

Mobile laser technological complex MLTC-20 with radiation power 20 kW and radiation wavelength 1.07 μm created in SRC RF TRINITI on the base of a three cw fiber Yb lasers is used successfully at remote cutting of the metalworks at carrying out of the emergency-reduction works on the out of control gas wells. In this work the results of the investigation of the possibility and the efficiency of laser radiation application for remote cutting of metals on the emergency oil wells have been presented. Measurements of the mean absorption coefficient of the radiation of a cw fiber Yb laser under its propagation in a flame of burning oil in dependence on radiation intensity have been carried out. It was shown that at the intensity ~104 W/cm2 the absorption coefficient traverses the maximum where its value is equal to ~0.1 cm-1, and at the intensity increasing to the values 105 - 106 W/cm2 it stabilizes on a small level ~5·10-3 - 10-2 cm-1. It is established that the maximal velocity and the efficiency of remote cutting of the steel plates with a thickness up to 10 mm by the radiation with the intensity 106 W/cm2 exceed these factors at the intensity 104 W/cm2. The possibility of the efficient remote cutting of steel plate with a thickness of 60 mm by laser radiation having the power 7.5 kW and the intensity 105 W/cm2 has been demonstrated.

Standardized performance tests of collectors of solar thermal energy - A flat-plate copper collector with parallel mylar striping

NASA Technical Reports Server (NTRS)

Johnson, S. M.

1976-01-01

Basic test results are reported for a flat plate solar collector whose performance was determined in a solar simulator. The collector was tested over ranges of inlet temperatures, fluxes and one coolant flow rate. Collector efficiency is correlated in terms of inlet temperature and flux level.

Investigation of heave response of the deepwater octagonal FDPSO using various heave plate configurations

NASA Astrophysics Data System (ADS)

Yu, Chenfang; Hu, Zhiqiang; Wang, Shisheng

2017-12-01

Heave plates can be employed to control undesirable heave motion amplitudes of the deepwater octagonal Floating, Drilling, Production, Storage, and Offloading (FDPSO) platform. Numerical simulations and model tests were applied to analyze and investigate the hydrodynamic response and the feasibility of the heave plate configurations. The diameter and the depth below the free surface of a single-layer heave plate, as well as the spacing of two-layer heave plates, were considered as the primary variables when studying the effect of heave plates on FDPSO hydrodynamics. The analysis results indicate that the heave plate diameter significantly affects the heave hydrodynamics, and heave performance could be improved with an increased diameter. In addition, increasing the depth below the free surface of a single-layer heave plate does not effectively suppress the heave motion within the range of draft depths tested. The target FDPSO obtained better heave characteristics with increased spacing between the two-layer heave plates. Furthermore, the global performances of the octagonal FDPSO with these typical heave plate configurations were comparatively analyzed. The results indicate that from a hydrodynamic point of view, the single-layer heave plate configuration has an advantage over the two-layer heave plate configuration.

Reliability assessment of different plate theories for elastic wave propagation analysis in functionally graded plates.

PubMed

Mehrkash, Milad; Azhari, Mojtaba; Mirdamadi, Hamid Reza

2014-01-01

The importance of elastic wave propagation problem in plates arises from the application of ultrasonic elastic waves in non-destructive evaluation of plate-like structures. However, precise study and analysis of acoustic guided waves especially in non-homogeneous waveguides such as functionally graded plates are so complicated that exact elastodynamic methods are rarely employed in practical applications. Thus, the simple approximate plate theories have attracted much interest for the calculation of wave fields in FGM plates. Therefore, in the current research, the classical plate theory (CPT), first-order shear deformation theory (FSDT) and third-order shear deformation theory (TSDT) are used to obtain the transient responses of flexural waves in FGM plates subjected to transverse impulsive loadings. Moreover, comparing the results with those based on a well recognized hybrid numerical method (HNM), we examine the accuracy of the plate theories for several plates of various thicknesses under excitations of different frequencies. The material properties of the plate are assumed to vary across the plate thickness according to a simple power-law distribution in terms of volume fractions of constituents. In all analyses, spatial Fourier transform together with modal analysis are applied to compute displacement responses of the plates. A comparison of the results demonstrates the reliability ranges of the approximate plate theories for elastic wave propagation analysis in FGM plates. Furthermore, based on various examples, it is shown that whenever the plate theories are used within the appropriate ranges of plate thickness and frequency content, solution process in wave number-time domain based on modal analysis approach is not only sufficient but also efficient for finding the transient waveforms in FGM plates. Copyright © 2013 Elsevier B.V. All rights reserved.

Target Plate Material Influence on Fullerene-C60 Laser Desorption/Ionization Efficiency

NASA Astrophysics Data System (ADS)

Zeegers, Guido P.; Günthardt, Barbara F.; Zenobi, Renato

2016-04-01

Systematic laser desorption/ionization (LDI) experiments of fullerene-C60 on a wide range of target plate materials were conducted to gain insight into the initial ion formation in matrix-assisted laser desorption/ionization (MALDI) mass spectrometry. The positive and negative ion signal intensities of precursor, fragment, and cluster ions were monitored, varying both the laser fluence (0-3.53 Jcm-2) and the ion extraction delay time (0-950 ns). The resulting species-specific ion signal intensities are an indication for the ionization mechanisms that contribute to LDI and the time frames in which they operate, providing insight in the (MA)LDI primary ionization. An increasing electrical resistivity of the target plate material increases the fullerene-C60 precursor and fragment anion signal intensity. Inconel 625 and Ti90/Al6/V4, both highly electrically resistive, provide the highest anion signal intensities, exceeding the cation signal intensity by a factor ~1.4 for the latter. We present a mechanism based on transient electrical field strength reduction to explain this trend. Fullerene-C60 cluster anion formation is negligible, which could be due to the high extraction potential. Cluster cations, however, are readily formed, although for high laser fluences, the preferred channel is formation of precursor and fragment cations. Ion signal intensity depends greatly on the choice of substrate material, and careful substrate selection could, therefore, allow for more sensitive (MA)LDI measurements.

Towards high-resolution mantle convection simulations

NASA Astrophysics Data System (ADS)

Höink, T.; Richards, M. A.; Lenardic, A.

2009-12-01

The motion of tectonic plates at the Earth’s surface, earthquakes, most forms of volcanism, the growth and evolution of continents, and the volatile fluxes that govern the composition and evolution of the oceans and atmosphere are all controlled by the process of solid-state thermal convection in the Earth’s rocky mantle, with perhaps a minor contribution from convection in the iron core. Similar processes govern the evolution of other planetary objects such as Mars, Venus, Titan, and Europa, all of which might conceivably shed light on the origin and evolution of life on Earth. Modeling and understanding this complicated dynamical system is one of the true “grand challenges” of Earth and planetary science. In the past three decades much progress towards understanding the dynamics of mantle convection has been made, with the increasing aid of computational modeling. Numerical sophistication has evolved significantly, and a small number of independent codes have been successfully employed. Computational power continues to increase dramatically, and with it the ability to resolve increasingly finer fluid mechanical structures. Yet, the perhaps most often cited limitation in numerical modeling based publications is still the limitation of computing power, because the ability to resolve thermal boundary layers within the convecting mantle (e.g., lithospheric plates), requires a spatial resolution of ~ 10 km. At present, the largest supercomputing facilities still barely approach the power to resolve this length scale in mantle convection simulations that include the physics necessary to model plate-like behavior. Our goal is to use supercomputing facilities to perform 3D spherical mantle convection simulations that include the ingredients for plate-like behavior, i.e. strongly temperature- and stress-dependent viscosity, at Earth-like convective vigor with a global resolution of order 10 km. In order to qualify to use such facilities, it is also necessary to demonstrate good parallel efficiency. Here we will present two kinds of results: (1) scaling properties of the community code CitcomS on DOE/NERSC's supercomputer Franklin for up to ~ 6000 processors, and (2) preliminary simulations that illustrate the role of a low-viscosity asthenosphere in plate-like behavior in mantle convection.

Optimization of the acoustic absorption coefficients of certain functional absorbents

NASA Technical Reports Server (NTRS)

Pocsa, V.; Biborosch, L.; Veres, A.; Halpert, E.; Lorian, R.; Botos, T.

1974-01-01

The sound absorption coefficients of some functional absorbents (mineral wool plates) are determined by the reverberation chamber method. The influence of the angle of inclination of the sound absorbing material with respect to the surface to be treated is analyzed as well as the influence of the covering index, defined as the ratio of the designed area of a plate and the area of the treated surface belonging to another plate. As compared with the conventional method of applying sound-absorbing plates, the analyzed structures have a higher technological and economical efficiency. The optimum structure corresponds to an angle of inclination of 15 deg and a covering index of 0.8.

Directivity pattern of the sound radiated from axisymmetric stepped plates.

PubMed

He, Xiping; Yan, Xiuli; Li, Na

2016-08-01

For the purpose of optimal design and efficient utilization of the kind of stepped plate radiator in air, in this contribution, an approach for calculation of the directivity pattern of the sound radiated from a stepped plate in flexural vibration with a free edge is developed based on Kirchhoff-Love hypothesis and Rayleigh integral principle. Experimental tests of directivity pattern for a fabricated flat plate and two fabricated plates with one and two step radiators were carried out. It shows that the configuration of the measured directivity patterns by the proposed analytic approach is similar to those of the calculated approach. Comparison of the agreement between the calculated directivity pattern of a stepped plate and its corresponding theoretical piston show that the former radiator is equivalent to the latter, and the diffraction field generated by the unbaffled upper surface may be small. It also shows that the directivity pattern of a stepped radiator is independent of the metallic material but dependent on the thickness of base plate and resonant frequency. The thicker the thickness of base plate, the more directive the radiation is. The proposed analytic approach in this work may be adopted for any other plates with multi-steps.

An exact analysis of a rectangular plate piezoelectric generator.

PubMed

Yang, Jiashi; Chen, Ziguang; Hu, Yuantai

2007-01-01

We study thickness-twist vibration of a finite, piezoelectric plate of polarized ceramics or 6-mm crystals driven by surface mechanical loads. An exact solution from the three-dimensional equations of piezoelectricity is obtained. The plate is properly electroded and connected to a circuit such that an electric output is generated. The structure analyzed represents a piezoelectric generator for converting mechanical energy to electrical energy. Analytical expressions for the output voltage, current, power, efficiency, and power density are given. The basic behaviors of the generator are shown by numerical results.

The effect of plate position and size on tibial slope in high tibial osteotomy: a cadaveric study.

PubMed

Rubino, L Joseph; Schoderbek, Robert J; Golish, S Raymond; Baumfeld, Joshua; Miller, Mark D

2008-01-01

Opening wedge high tibial osteotomies are performed for degenerative changes and varus. Opening wedge osteotomies can change proximal tibial slope in the sagittal plane, possibly imparting stability in the ACL-deficient knee. The aim of this study was to assess the effect of plate position and size on change in tibial slope. Eight cadaveric knees underwent opening wedge high tibial osteotomy with Puddu plates of each different size. Plates were placed anterior, central, and posterior for each size used. Lateral radiographs were obtained. Tibial slope was measured and compared with baseline slope. Tibial slope was affected by plate position (P < 0.05) and size (P < 0.001). Smaller, posterior plates had less effect on tibial slope. However, anterior and central plates increased tibial slope over all plate sizes (P < 0.05). This study found that tibial slope increases with opening wedge high tibial osteotomy. Larger corrections and anterior placement of the plate are associated with larger increases in slope.

Experimental Spin Testing of Integrally Damped Composite Plates

NASA Technical Reports Server (NTRS)

Kosmatka, John

1998-01-01

The experimental behavior of spinning laminated composite pretwisted plates (turbo-fan blade-like) with small (less than 10% by volume) integral viscoelastic damping patches was investigated at NASA-Lewis Research Center. Ten different plate sets were experimentally spin tested and the resulting data was analyzed. The first-four plate sets investigated tailoring patch locations and definitions to damp specific modes on spinning flat graphite/epoxy plates as a function of rotational speed. The remaining six plate sets investigated damping patch size and location on specific modes of pretwisted (30 degrees) graphite/epoxy plates. The results reveal that: (1) significant amount of damping can be added using a small amount of damping material, (2) the damped plates experienced no failures up to the tested 28,000 g's and 750,000 cycles, (3) centrifugal loads caused an increase in bending frequencies and corresponding reductions in bending damping levels that are proportional to the bending stiffness increase, and (4) the centrifugal loads caused a decrease in torsion natural frequency and increase in damping levels of pretwisted composite plates.

Visual plate waste in hospitalized patients: length of stay and diet order.

PubMed

Kandiah, Jay; Stinnett, Lydia; Lutton, Dale

2006-10-01

The purpose of this pilot research was to investigate the effect of diet order, sex, diagnosis, and length of stay on visual lunch plate waste in hospitalized patients. Information on 346 patients was collected using the computer program CBORD Diet Office. Visual plate waste during lunch was measured and analyzed for 4 consecutive days. Neither sex nor diagnosis at admittance was associated with visual plate waste. However, the odds of visual plate waste increased by 14.1% for every day a patient was admitted. In patients receiving a diabetic diet order, odds of visual plate waste decreased by 61.2%, indicating there was reduction in plate waste. Conversely, in patients receiving altered consistency diet orders, odds of visual plate waste increased by 344%, signifying a rise in plate waste. Due to an increase of visual plate waste associated with long length of stay and altered consistency diet orders, registered dietitians working in acute-care facilities need to develop strategies to create cost-effective, nutritionally balanced, altered consistency diets that would enhance patient acceptance and consumption of food.

The System for Quick Search of the Astronomical Objects and Events in the Digital Plate Archives.

NASA Astrophysics Data System (ADS)

Sergeev, A. V.; Sergeeva, T. P.

From the middle of the XIX century observatories all over the world have accumulated about three millions astronomical plates contained the unique information about the Universe which can not be obtained or restored with the help of any newest facilities and technologies but may be useful for many modern astronomical investigations. The threat of astronomical plate archives loss caused by economical, technical or some other causes have put before world astronomical community a problem: the preservation of the unique information kept on those plates. The problem can be solved by transformation of the information from plates to digital form and keeping it on electronic data medium. We began a creation of a system for quick search and analysing of astronomical events and objects in digital plate archive of the Ukrainian Main astronomical observatory of NAS. Connection of the system to Internet will allow a remote user (astronomer or observer) to have access to digital plate archive and to work with it. For providing of the high efficiency of this work the plate database (list of the plates with all information about them and access software) are preparing. Modular structure of the system basic software and standard format of the plate image files allow future development of problem-oriented software for special astronomical researches.

Comparison of Mixing Characteristics for Several Fuel Injectors on an Open Plate and in a Ducted Flowpath Configuration at Hypervelocity Flow Conditions

NASA Technical Reports Server (NTRS)

Drozda, Tomasz G.; Shenoy, Rajiv R.; Passe, Bradley J.; Baurle, Robert A.; Drummond, J. Philip

2017-01-01

In order to reduce the cost and complexity associated with fuel injection and mixing experiments for high-speed flows, and to further enable optical access to the test section for nonintrusive diagnostics, the Enhanced Injection and Mixing Project (EIMP) utilizes an open flat plate configuration to characterize inert mixing properties of various fuel injectors for hypervelocity applications. The experiments also utilize reduced total temperature conditions to alleviate the need for hardware cooling. The use of "cold" flows and non-reacting mixtures for mixing experiments is not new, and has been extensively utilized as a screening technique for scramjet fuel injectors. The impact of reduced facility-air total temperature, and the use of inert fuel simulants, such as helium, on the mixing character of the flow has been assessed in previous numerical studies by the authors. Mixing performance was characterized for three different injectors: a strut, a ramp, and a flushwall. The present study focuses on the impact of using an open plate to approximate mixing in the duct. Toward this end, Reynolds-averaged simulations (RAS) were performed for the three fuel injectors in an open plate configuration and in a duct. The mixing parameters of interest, such as mixing efficiency and total pressure recovery, are then computed and compared for the two configurations. In addition to mixing efficiency and total pressure recovery, the combustion efficiency and thrust potential are also computed for the reacting simulations.

Electroless plating of silver nanoparticles on porous silicon for laser desorption/ionization mass spectrometry

NASA Astrophysics Data System (ADS)

Yan, Hong; Xu, Ning; Huang, Wen-Yi; Han, Huan-Mei; Xiao, Shou-Jun

2009-03-01

An improved DIOS (desorption ionization on porous silicon) method for laser desorption/ionization mass spectrometry (LDI MS) by electroless plating of silver nanoparticles (AgNPs) on porous silicon (PSi) was developed. By addition of 4-aminothiophenol (4-ATP) into the AgNO3 plating solution, the plating speed can be slowed down and simultaneously 4-ATP self-assembled monolayers (SAMs) on AgNPs (4-ATP/AgNPs) were formed. Both AgNPs and 4-ATP/AgNPs coated PSi substrates present much higher stability, sensitivity and reproducibility for LDI MS than the un-treated porous silicon ones. Their shelf life in air was tested for several weeks to a month and their mass spectra still displayed the same high quality and sensitivity as the freshly prepared ones. And more 4-ATP SAMs partly play a role of matrix to increase the ionization efficiency. A small organic molecule of tetrapyridinporphyrin (TPyP), oligomers of polyethylene glycol (PEG 400 and 2300), and a peptide of oxytocin were used as examples to demonstrate the feasibility of the silver-plated PSi as a matrix-free-like method for LDI MS. This approach can obtain limits of detection to femtomoles for TPyP, subpicomoles for oxytocin, and picomoles for PEG 400 and 2300, comparable to the traditional matrix method and much better than the DIOS method. It simplifies the sample preparation as a matrix-free-like method without addition of matrix molecules and homogenizes the sample spread over the spot for better and more even mass signals.

Plate-clearing tendencies and portion size are independently associated with main meal food intake in women: A laboratory study.

PubMed

Sheen, Florence; Hardman, Charlotte A; Robinson, Eric

2018-08-01

Larger portion sizes of food promote increased food intake, although the mechanisms explaining the portion size effect are unclear. In the present study we examined whether the tendency to clear one's plate when eating is associated with greater food intake in response to larger portion size. We recruited female participants who were either self-reported habitual plate clearers (N = 48) or non-plate clearers (N = 41) into a laboratory study. In a between-subjects design, participants were served either a 'normal' (500 g) or 'large' (1000 g) portion of pasta for lunch and ate as much as they desired. There was no significant interaction found between portion size and plate-clearing tendencies; portion size had a similar sized effect on food intake in both plate clearers and non-plate clearers. A significant main effect of portion size was found, whereby participants consumed significantly more when served the large versus the normal portion (100.55 g difference, p < .001, η p 2  = 0.16). There was also a significant main effect of plate clearing; participants with a tendency to clear their plate when eating consumed significantly more than non-plate clearers (68.21 g difference, p = .006, η p 2  = 0.08). The tendency to clear one's plate when eating was associated with increased food intake during a lunchtime meal. Increasing the portion size of the lunchtime meal increased food intake, although the tendency for a larger portion size to increase food intake was observed irrespective of participant plate-clearing tendencies. Crown Copyright © 2018. Published by Elsevier Ltd. All rights reserved.

Proceedings of the Flat-plate Solar Array Project Research Forum on High-efficiency Crystalline Silicon Solar Cells

NASA Technical Reports Server (NTRS)

Kachare, R.

1985-01-01

The high-efficiency crystalline silicon solar cells research forum addressed high-efficiency concepts, surface-interface effects, bulk effects, modeling and device processing. The topics were arranged into six interactive sessions, which focused on the state-of-the-art of device structures, identification of barriers to achieve high-efficiency cells and potential ways to overcome these barriers.

Experimental study on the sensitive depth of backwards detected light in turbid media.

PubMed

Zhang, Yunyao; Huang, Liqing; Zhang, Ning; Tian, Heng; Zhu, Jingping

2018-05-28

In the recent past, optical spectroscopy and imaging methods for biomedical diagnosis and target enhancing have been widely researched. The challenge to improve the performance of these methods is to know the sensitive depth of the backwards detected light well. Former research mainly employed a Monte Carlo method to run simulations to statistically describe the light sensitive depth. An experimental method for investigating the sensitive depth was developed and is presented here. An absorption plate was employed to remove all the light that may have travelled deeper than the plate, leaving only the light which cannot reach the plate. By measuring the received backwards light intensity and the depth between the probe and the plate, the light intensity distribution along the depth dimension can be achieved. The depth with the maximum light intensity was recorded as the sensitive depth. The experimental results showed that the maximum light intensity was nearly the same in a short depth range. It could be deduced that the sensitive depth was a range, rather than a single depth. This sensitive depth range as well as its central depth increased consistently with the increasing source-detection distance. Relationships between sensitive depth and optical properties were also investigated. It also showed that the reduced scattering coefficient affects the central sensitive depth and the range of the sensitive depth more than the absorption coefficient, so they cannot be simply added as reduced distinct coefficients to describe the sensitive depth. This study provides an efficient method for investigation of sensitive depth. It may facilitate the development of spectroscopy and imaging techniques for biomedical diagnosis and underwater imaging.

Composite coatings improve engines

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

Funatani, K.; Kurosawa, K.

1994-12-01

About 40% of the power loss in engine systems is attributed to the adverse effects of friction in reciprocating engine components. Over half of this power loss is caused by friction between pistons, piston rings, and cylinder bores. In addition, engine parts may be attacked by corrosive gasoline substitutes such as liquid propane gas and alcohol/gasoline mixtures. To solve both friction and corrosion problems, Nihon Parkerizing Co. has improved the nickel-phosphorus based ceramic composite (NCC) plating technology that was developed for cylinder bores and pistons by Suzuki Motor Co. in the mid 1970s. Iron and nickel-based composite plating technologies havemore » been investigated since the early 1970s, and a few have been used on small two-stroke motorcycle, outboard marine, snowmobile, and some luxury passenger car engine components. Both nickel- and iron-base plating processes are used on cylinders and pistons because they offer excellent wear and corrosion resistance. Nickel-base films have higher corrosion resistance than those based on iron, and are capable of withstanding the corrosive conditions characteristic of high methanol fuels. Unfortunately, they experience a decrease in hardness as operating temperatures increase. However, NCC coatings with phosphorus additions have high hardness even under severe operating conditions, and hardness increases upon exposure to elevated temperatures. In addition to high hardness and corrosion resistance, NCC coatings provide a low friction coefficient, which contributes to the reduction of friction losses between sliding components. When used in low-quality or alcohol fuels, the corrosion resistance of NCC coatings is far higher than that of Fe-P plating. Additionally, the coatings reduce wall and piston temperature, wear of ring groove and skirt, and carbon deposit formation, and they improve output power and torque. These advantages all contribute to the development of light and efficient engines with better fuel mileage.« less

Bituminous coal production in the Appalachian Basin; past, present, and future

USGS Publications Warehouse

Milici, R.C.

1999-01-01

This report on Appalachian basin coal production consists of four maps and associated graphs and tables, with links to the basic data that were used to construct the maps. Plate 1 shows the time (year) of maximum coal production, by county. For illustration purposes, the years of maximum production are grouped into decadal units. Plate 2 shows the amount of coal produced (tons) during the year of maximum coal production for each county. Plate 3 illustrates the cumulative coal production (tons) for each county since about the beginning of the 20th century. Plate 4 shows 1996 annual production by county. During the current (third) cycle of coal production in the Appalachian basin, only seven major coal-producing counties (those with more than 500 million tons cumulative production), including Greene County, Pa.; Boone, Kanawha, Logan, Mingo, and Monongalia Counties, W.Va.; and Pike County, Ky., exhibit a general increase in coal production. Other major coal-producing counties have either declined to a small percentage of their maximum production or are annually maintaining a moderate level of production. In general, the areas with current high coal production have large blocks of coal that are suitable for mining underground with highly efficient longwall methods, or are occupied by very large scale, relatively low cost surface mining operations. The estimated cumulative production for combined bituminous and anthracite coal is about 100 billion tons or less for the Appalachian basin. In general, it is anticipated that the remaining resources will be progressively of lower quality, will cost more to mine, and will become economical only as new technologies for extraction, beneficiation, and consumption are developed, and then only if prices for coal increase.

Controlled higher-order transverse mode conversion from a fiber laser by polarization manipulation

NASA Astrophysics Data System (ADS)

Huang, Bin; Yi, Qian; Yang, Lingling; Zhao, Chujun; Wen, Shuangchun

2018-02-01

We report a vectorial fiber laser with controlled transverse mode conversion by intra-cavity polarization manipulation. By combining a q-plate and two quarter-wave plates (QWPs), we can generate a switchable polarization state output represented by the higher-order Poincaré sphere (l = +1, l = -1), and distinguish the fourfold degenerate LP11 mode. The four transverse vector modes can be obtained and switched in a flexible way, and the slope efficiency of the fiber laser can reach up to 39.4%. This compactness, high efficiency, and switchable operation potential will benefit a range of applications, such as materials processing, particle manipulation, etc.

Synchrotron radiation calibration of the EUVE variable line-spaced diffraction gratings at the NBS SURF II facility

NASA Technical Reports Server (NTRS)

Jelinsky, P.; Jelinsky, S. R.; Miller, A.; Vallerga, J.; Malina, R. F.

1988-01-01

The Extreme Ultraviolet Explorer (EUVE) has a spectrometer which utilizes variable line-spaced, plane diffraction gratings in the converging beam of a Wolter-Schwarzschild type II mirror. The gratings, microchannel plate detector, and thin film filters have been calibrated with continuum radiation provided by the NBS SURF II facility. These were calibrated in a continuum beam to find edges or other sharp spectral features in the transmission of the filters, quantum efficiency of the microchannel plate detector, and efficiency of the gratings. The details of the calibration procedure and the results of the calibration are presented.

Performance of double -pass solar collector with CPC and fins for heat transfer enhancement

NASA Astrophysics Data System (ADS)

Alfegi, Ebrahim M. A.; Abosbaia, Alhadi A. S.; Mezughi, Khaled M. A.; Sopian, Kamaruzzaman

2013-06-01

The temperature of photovoltaic modules increases when it absorbs solar radiation, causing a decrease in efficiency. This undesirable effect can be partially avoided by applying a heat recovery unit with fluid circulation (air or water) with the photovoltaic module. Such unit is called photovoltaic / thermal collector (pv/t) or hybrid (pv/t). In this unit, photovoltaic cells were pasted directly on the flat plate absorber. An experimental study of a solar air heater with photovoltaic cell located at the absorber with fins and compound parabolic collector for heat transfer enhancement and increasing the number of reflection on the cells have been conducted. The performance of the photovoltaic, thermal, and combined pv/t collector over range of operating conditions and the results was discussed. Results at solar irradiance of 500 W/m2 show that the combined pv/t efficiency is increasing from 37.28 % to 81.41 % at mass flow rates various from 0.029 to 0.436 kg/s.

Generation of ozone by pulsed corona discharge over water surface in hybrid gas liquid electrical discharge reactor

NASA Astrophysics Data System (ADS)

Lukes, Petr; Clupek, Martin; Babicky, Vaclav; Janda, Vaclav; Sunka, Pavel

2005-02-01

Ozone formation by a pulse positive corona discharge generated in the gas phase between a planar high voltage electrode made from reticulated vitreous carbon and a water surface with an immersed ground stainless steel plate electrode was investigated under various operating conditions. The effects of gas flow rate (0.5-3 litre min-1), discharge gap spacing (2.5-10 mm), applied input power (2-45 W) and gas composition (oxygen containing argon or nitrogen) on ozone production were determined. Ozone concentration increased with increasing power input and with increasing discharge gap. The production of ozone was significantly affected by the presence of water vapour formed through vaporization of water at the gas-liquid interface by the action of the gas phase discharge. The highest energy efficiency for ozone production was obtained using high voltage pulses of approximately 150 ns duration in Ar/O2 mixtures with the maximum efficiency (energy yield) of 23 g kW h-1 for 40% argon content.

The ISR Asymmetrical Capacitor Thruster: Experimental Results and Improved Designs

NASA Technical Reports Server (NTRS)

Canning, Francis X.; Cole, John; Campbell, Jonathan; Winet, Edwin

2004-01-01

A variety of Asymmetrical Capacitor Thrusters has been built and tested at the Institute for Scientific Research (ISR). The thrust produced for various voltages has been measured, along with the current flowing, both between the plates and to ground through the air (or other gas). VHF radiation due to Trichel pulses has been measured and correlated over short time scales to the current flowing through the capacitor. A series of designs were tested, which were increasingly efficient. Sharp features on the leading capacitor surface (e.g., a disk) were found to increase the thrust. Surprisingly, combining that with sharp wires on the trailing edge of the device produced the largest thrust. Tests were performed for both polarizations of the applied voltage, and for grounding one or the other capacitor plate. In general (but not always) it was found that the direction of the thrust depended on the asymmetry of the capacitor rather than on the polarization of the voltage. While no force was measured in a vacuum, some suggested design changes are given for operation in reduced pressures.

Using Latex Balls and Acrylic Resin Plates to Investigate the Stacking Arrangement and Packing Efficiency of Metal Crystals

ERIC Educational Resources Information Center

Ohashi, Atsushi

2015-01-01

A high-school third-year or undergraduate first-semester general chemistry laboratory experiment introducing simple-cubic, face-centered cubic, body-centered cubic, and hexagonal closest packing unit cells is presented. Latex balls and acrylic resin plates are employed to make each atomic arrangement. The volume of the vacant space in each cell is…

Enhancing Sensitivity of Liquid Chromatography-Mass Spectrometry of Peptides and Proteins Using Supercharging Agents.

PubMed

Nshanian, Michael; Lakshmanan, Rajeswari; Chen, Hao; Ogorzalek Loo, Rachel R; Loo, Joseph A

2018-04-01

Trifluoroacetic acid (TFA) is often used as a mobile phase modifier to enhance reversed phase chromatographic performance. TFA adjusts solution pH and is an ion-pairing agent, but it is not typically suitable for electrospray ionization-mass spectrometry (ESI-MS) and liquid chromatography/MS (LC/MS) because of its significant signal suppression. Supercharging agents elevate peptide and protein charge states in ESI, increasing tandem MS (MS/MS) efficiency. Here, LC/MS protein supercharging was effected by adding agents to LC mobile phase solvents. Significantly, the ionization suppression generally observed with TFA was, for the most part, rescued by supercharging agents, with improved separation efficiency (higher number of theoretical plates) and lowered detection limits.

Discontinuous Galerkin Methods and High-Speed Turbulent Flows

NASA Astrophysics Data System (ADS)

Atak, Muhammed; Larsson, Johan; Munz, Claus-Dieter

2014-11-01

Discontinuous Galerkin methods gain increasing importance within the CFD community as they combine arbitrary high order of accuracy in complex geometries with parallel efficiency. Particularly the discontinuous Galerkin spectral element method (DGSEM) is a promising candidate for both the direct numerical simulation (DNS) and large eddy simulation (LES) of turbulent flows due to its excellent scaling attributes. In this talk, we present a DNS of a compressible turbulent boundary layer along a flat plate at a free-stream Mach number of M = 2.67 and assess the computational efficiency of the DGSEM at performing high-fidelity simulations of both transitional and turbulent boundary layers. We compare the accuracy of the results as well as the computational performance to results using a high order finite difference method.

Dilution-to-extinction cultivation of leaf-inhabiting endophytic fungi in beech (Fagus sylvatica L.)--different cultivation techniques influence fungal biodiversity assessment.

PubMed

Unterseher, Martin; Schnittler, Martin

2009-05-01

Two cultivation-based isolation techniques - the incubation of leaf fragments (fragment plating) and dilution-to-extinction culturing on malt extract agar - were compared for recovery of foliar endophytic fungi from Fagus sylvatica near Greifswald, north-east Germany. Morphological-anatomical characters of vegetative and sporulating cultures and ITS sequences were used to assign morphotypes and taxonomic information to the isolates. Data analysis included species-accumulation curves, richness estimators, multivariate statistics and null model testing. Fragment plating and extinction culturing were significantly complementary with regard to species composition, because around two-thirds of the 35 fungal taxa were isolated with only one of the two cultivation techniques. The difference in outcomes highlights the need for caution in assessing fungal biodiversity based upon single isolation techniques. The efficiency of cultivation-based studies of fungal endophytes was significantly increased with the combination of the two isolation methods and estimations of species richness, when compared with a 20-years old reference study, which needed three times more isolates with fragment plating to attain the same species richness. Intensified testing and optimisation of extinction culturing in endophyte research is advocated.

Research of hail impact on aircraft wheel door with lattice hybrid structure

NASA Astrophysics Data System (ADS)

Li, Shengze; Jin, Feng; Zhang, Weihua; Meng, Xuanzhu

2016-09-01

Aimed at a long lasting issue of hail impact on aircraft structures and aviation safety due to its high speed, the resistance performance of hail impact on the wheel door of aircraft with lattice hybrid structure is investigated. The proper anti-hail structure can be designed both efficiency and precision based on this work. The dynamic responses of 8 different sandwich plates in diverse impact speed are measured. Smoothed Particle Hydrodynamic (SPH) method is introduced to mimic the speciality of solid-liquid mixture trait of hailstone during the impact process. The deformation and damage degree of upper and lower panel of sandwich plate are analysed. The application range and failure mode for the relevant structure, as well as the energy absorbing ratio between lattice structure and aluminium foam are summarized. Results show that the tetrahedral sandwich plate with aluminium foam core is confirmed the best for absorbing energy. Furthermore, the high absorption characteristics of foam material enhance the capability of the impact resistance for the composition with lattice structure without increasing the structure surface density. The results of study are of worth to provide a reliable basis for reduced weight aircraft wheel door.

Simulative method for determining the optimal operating conditions for a cooling plate for lithium-ion battery cell modules

NASA Astrophysics Data System (ADS)

Smith, Joshua; Hinterberger, Michael; Hable, Peter; Koehler, Juergen

2014-12-01

Extended battery system lifetime and reduced costs are essential to the success of electric vehicles. An effective thermal management strategy is one method of enhancing system lifetime increasing vehicle range. Vehicle-typical space restrictions favor the minimization of battery thermal management system (BTMS) size and weight, making their production and subsequent vehicle integration extremely difficult and complex. Due to these space requirements, a cooling plate as part of a water-glycerol cooling circuit is commonly implemented. This paper presents a computational fluid dynamics (CFD) model and multi-objective analysis technique for determining the thermal effect of coolant flow rate and inlet temperature in a cooling plate-at a range of vehicle operating conditions-on a battery system, thereby providing a dynamic input for one-dimensional models. Traditionally, one-dimensional vehicular thermal management system models assume a static heat input from components such as a battery system: as a result, the components are designed for a set coolant input (flow rate and inlet temperature). Such a design method is insufficient for dynamic thermal management models and control strategies, thereby compromising system efficiency. The presented approach allows for optimal BMTS design and integration in the vehicular coolant circuit.

Friction and wear study of NR/SBR blends with Si3N4Filler

NASA Astrophysics Data System (ADS)

GaneshKumar, A.; Balaganesan, G.; Sivakumar, M. S.

2018-04-01

The aim of this paper is to investigate mechanical and frictional properties of natural rubber/styrene butadiene rubber (NR/SBR) blends with and without silicon nitride (Si3N4) filler. The rubber is surface modified by silane coupling agent (Si-69) for enhancing hydrophobic property. The Si3N4of percentage 0 1, 3, 5 and 7, is incorporated into NR/SBR rubber compounds with 20% precipitated silica. The specimens with and without fillers are prepared as per standard for tensile and friction testing. Fourier transform infrared (FTIR) spectroscopy test is conducted and it is inferred that the coupling agent is covalently bonded on the surface of Si3N4 particles and an organic coating layer is formed. The co-efficient of friction and specific wear rate of NR/SBR blends are examined using an in-house built friction tester in a disc-on-plate (DOP) configuration. The specimens are tested to find coefficient of friction (COF) against steel grip antiskid plate under dry, mud, wet and oil environmental conditions. It is found that the increase in tensile strength and modulus at low percentage of Si3N4 dispersion. It is also observed that increase in sliding friction co-efficient and decrease in wear rate for 1% of Si3N4 dispersion in NR/SBR blends. The friction tested surfaces are inspected using Scanning Electron Microscope (SEM) and 3D non contact surface profiler.

Characteristic and comparison of different submounts on concentrating photovoltaic module

NASA Astrophysics Data System (ADS)

Lee, Yueh-Mu; Shih, Zun-Hao; Hong, Hwen-Fen; Shin, Hwa-Yuh; Kuo, Cherng-Tsong

2014-09-01

High concentration photovoltaics systems employ concentrating optics consisting of dish reflectors or fresnel lenses that concentrate sunlight to 500 suns or more. In general, under concentrating light operation condition, the device temperature rises quickly and the open-circuit voltage of solar cell will decrease with increasing temperature; therefore, the system output power or energy-conversion efficiency will decrease while temperature of solar cell increased. In this study, we analyze the ceramic thermal resistance and propose a direct temperature measurement method of the solar cell. The direct temperature measurement of the cell and the ceramic was achieved by utilizing buried thermocouples with a diameter of 50 μm between the cell/ceramic and aluminum plate. The different light flux densities ranging from 500 to 800 W/m2 at 100 W/m2 interval by solar simulator are provided to measure temperature, and the cell temperatures measured are 39.8 °C, 41 °C, 45 °C and 48 °C, respectively. The temperature differences between the cell and aluminum plate of the light flux densities from 500 W/m2 to 800 W/m2 are in the range of 4.2 °C to 8 °C. Accordingly we can obtain the temperature distribution of HCPV module at difference region. The results can help us to optimize module package technology and to choose better material applied to the module to improve conversion efficiency of the cell.

Increasing the information acquisition volume in iris recognition systems.

PubMed

Barwick, D Shane

2008-09-10

A significant hurdle for the widespread adoption of iris recognition in security applications is that the typically small imaging volume for eye placement results in systems that are not user friendly. Separable cubic phase plates at the lens pupil have been shown to ameliorate this disadvantage by increasing the depth of field. However, these phase masks have limitations on how efficiently they can capture the information-bearing spatial frequencies in iris images. The performance gains in information acquisition that can be achieved by more general, nonseparable phase masks is demonstrated. A detailed design method is presented, and simulations using representative designs allow for performance comparisons.

Experimental study of heat transfer and thermal performance with longitudinal fins of solar air heater

PubMed Central

Chabane, Foued; Moummi, Noureddine; Benramache, Said

2013-01-01

The thermal performance of a single pass solar air heater with five fins attached was investigated experimentally. Longitudinal fins were used inferior the absorber plate to increase the heat exchange and render the flow fluid in the channel uniform. The effect of mass flow rate of air on the outlet temperature, the heat transfer in the thickness of the solar collector, and the thermal efficiency were studied. Experiments were performed for two air mass flow rates of 0.012 and 0.016 kg s−1. Moreover, the maximum efficiency values obtained for the 0.012 and 0.016 kg s−1 with and without fins were 40.02%, 51.50% and 34.92%, 43.94%, respectively. A comparison of the results of the mass flow rates by solar collector with and without fins shows a substantial enhancement in the thermal efficiency. PMID:25685486

Experimental study of heat transfer and thermal performance with longitudinal fins of solar air heater.

PubMed

Chabane, Foued; Moummi, Noureddine; Benramache, Said

2014-03-01

The thermal performance of a single pass solar air heater with five fins attached was investigated experimentally. Longitudinal fins were used inferior the absorber plate to increase the heat exchange and render the flow fluid in the channel uniform. The effect of mass flow rate of air on the outlet temperature, the heat transfer in the thickness of the solar collector, and the thermal efficiency were studied. Experiments were performed for two air mass flow rates of 0.012 and 0.016 kg s(-1). Moreover, the maximum efficiency values obtained for the 0.012 and 0.016 kg s(-1) with and without fins were 40.02%, 51.50% and 34.92%, 43.94%, respectively. A comparison of the results of the mass flow rates by solar collector with and without fins shows a substantial enhancement in the thermal efficiency.

Incorporation of ionic liquid into porous polymer monoliths to enhance the separation of small molecules in reversed-phase high-performance liquid chromatography.

PubMed

Wang, Jiafei; Bai, Ligai; Wei, Zhen; Qin, Junxiao; Ma, Yamin; Liu, Haiyan

2015-06-01

An ionic liquid was incorporated into the porous polymer monoliths to afford stationary phases with enhanced chromatographic performance for small molecules in reversed-phase high-performance liquid chromatography. The effect of the ionic liquid in the polymerization mixture on the performance of the monoliths was studied in detail. While monoliths without ionic liquid exhibited poor resolution and low efficiency, the addition of ionic liquid to the polymerization mixture provides highly increased resolution and high efficiency. The chromatographic performances of the monoliths were demonstrated by the separations of various small molecules including aromatic hydrocarbons, isomers, and homologues using a binary polar mobile phase. The present column efficiency reached 27 000 plates/m, which showed that the ionic liquid monoliths are alternative stationary phases in the separation of small molecules by high-performance liquid chromatography. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Nonlinear flow affects hydrodynamic forces and neutrophil adhesion rates in cone-plate viscometers.

PubMed Central

Shankaran, H; Neelamegham, S

2001-01-01

We present a theoretical and experimental analysis of the effects of nonlinear flow in a cone-plate viscometer. The analysis predicts that flow in the viscometer is a function of two parameters, the Reynolds number and the cone angle. Nonlinear flow occurs at high shear rates and causes spatial variations in wall shear stress, collision frequency, interparticle forces and attachment times within the viscometer. We examined the effect of these features on cellular adhesion kinetics. Based on recent data (Taylor, A. D., S. Neelamegham, J. D. Hellums, et al. 1996. Biophys. J. 71:3488-3500), we modeled neutrophil homotypic aggregation as a process that is integrin-limited at low shear and selectin-limited at high shear. Our calculations suggest that selectin and integrin on-rates lie in the order of 10(-2)-10(-4)/s. They also indicate that secondary flow causes positional variations in adhesion efficiency in the viscometer, and that the overall efficiency is dependent not only on the shear rate, but also the sample volume and the cone angle. Experiments performed with isolated neutrophils confirmed these predictions. In these experiments, enhancing secondary flow by increasing the sample volume from 100 to 1000 microl at 1500/s for a 2 degrees cone caused up to an approximately 45% drop in adhesion efficiency. Our results suggest that secondary flow may significantly influence cellular aggregation, platelet activation, and endothelial cell mechanotransduction measurements made in the viscometer over the range of conditions applied in typical biological studies. PMID:11371440

N-heptane decomposition in multi-needle to plate electrical discharge

NASA Astrophysics Data System (ADS)

Pekarek, Stanislav; Pospisil, Milan

2003-10-01

Plasma based technologies are becoming more and more important for destruction of volatile organic compounds in air streams. The most frequent electrical discharges tested for VOC decomposition are corona and dielectric barrier discharge. We proposed [1] multi-hollow needles to plate atmospheric pressure discharge enhanced by the flow of the mixture of air with VOC through the needles. In this case all reactive mixture will pass through the active zone of the discharge. The high-speed gas flow near the exit of the needle will also efficiently cool the electrodes. Hence the higher values of the discharge current can be obtained without the danger of the discharge transition to the spark. The chemical reactions leading to the VOC decomposition can therefore be enhanced [2]. We performed an experimental study of the n-heptane decomposition efficiency on its concentration in air in the input of the discharge. We choose n-heptane, an important part of organic solvents and part of automotive fuels, as a representative of saturated alkanes. We found that with decreasing n-heptane concentration the decomposition efficiency increases. Acknowledgement: This work was supported by the research program No: J04/98:212300016 "Pollution control and monitoring of the Environment" of the Czech Technical University in Prague. References [1] S. Pekárek, V. Køíha, M. Pospíil - J. Physics D, Appl. Physics, 34, 117 (2001). [2] O. Goosens, T. Callebaut, Y. Akishev, C. Leys - IEEE Trans. Plasma Sc. 30, 176 (2002).

Modeling the hydrodynamics of Phloem sieve plates.

PubMed

Jensen, Kaare Hartvig; Mullendore, Daniel Leroy; Holbrook, Noel Michele; Bohr, Tomas; Knoblauch, Michael; Bruus, Henrik

2012-01-01

Sieve plates have an enormous impact on the efficiency of the phloem vascular system of plants, responsible for the distribution of photosynthetic products. These thin plates, which separate neighboring phloem cells, are perforated by a large number of tiny sieve pores and are believed to play a crucial role in protecting the phloem sap from intruding animals by blocking flow when the phloem cell is damaged. The resistance to the flow of viscous sap in the phloem vascular system is strongly affected by the presence of the sieve plates, but the hydrodynamics of the flow through them remains poorly understood. We propose a theoretical model for quantifying the effect of sieve plates on the phloem in the plant, thus unifying and improving previous work in the field. Numerical simulations of the flow in real and idealized phloem channels verify our model, and anatomical data from 19 plant species are investigated. We find that the sieve plate resistance is correlated to the cell lumen resistance, and that the sieve plate and the lumen contribute almost equally to the total hydraulic resistance of the phloem translocation pathway.

Electroplated Fe-Co-Ni films prepared from deep-eutectic-solvent-based plating baths

NASA Astrophysics Data System (ADS)

Yanai, Takeshi; Shiraishi, Kotaro; Akiyoshi, Toshiki; Azuma, Keita; Watanabe, Yoshimasa; Ohgai, Takeshi; Morimura, Takao; Nakano, Masaki; Fukunaga, Hirotoshi

2016-05-01

We fabricated soft magnetic films from DES-based plating baths, and investigated magnetic properties of the plated films. The plating baths were obtained by stirring the mixture of choline chloride, ethylene glycol, FeCl2 ṡ 4H2O, NiCl2 ṡ 6H2O and CoCl2 ṡ 6H2O. The composition of the electroplated film depended on the amount of the reagent in the plating bath, and we consequently obtained the films with various composition. The current efficiency of the plating process shows high values (> 88 %) in the wide composition range. The soft magnetic films with low coercivity were obtained at the Fe compositions of ≈ 30 at.% and > 80 at.%, and we found that low coercivity could be realized by the control of the film composition. We also found that the Fe-rich films prepared from DES-based plating bath have some advantages as a soft magnetic phase for a nanocomposite magnet due to their high saturation magnetization and very fine crystal structure.

Modeling the Hydrodynamics of Phloem Sieve Plates

PubMed Central

Jensen, Kaare Hartvig; Mullendore, Daniel Leroy; Holbrook, Noel Michele; Bohr, Tomas; Knoblauch, Michael; Bruus, Henrik

2012-01-01

Sieve plates have an enormous impact on the efficiency of the phloem vascular system of plants, responsible for the distribution of photosynthetic products. These thin plates, which separate neighboring phloem cells, are perforated by a large number of tiny sieve pores and are believed to play a crucial role in protecting the phloem sap from intruding animals by blocking flow when the phloem cell is damaged. The resistance to the flow of viscous sap in the phloem vascular system is strongly affected by the presence of the sieve plates, but the hydrodynamics of the flow through them remains poorly understood. We propose a theoretical model for quantifying the effect of sieve plates on the phloem in the plant, thus unifying and improving previous work in the field. Numerical simulations of the flow in real and idealized phloem channels verify our model, and anatomical data from 19 plant species are investigated. We find that the sieve plate resistance is correlated to the cell lumen resistance, and that the sieve plate and the lumen contribute almost equally to the total hydraulic resistance of the phloem translocation pathway. PMID:22811681

An efficient and cost-effective microchannel plate detector for slow neutron radiography

NASA Astrophysics Data System (ADS)

Wiggins, B. B.; Vadas, J.; Bancroft, D.; deSouza, Z. O.; Huston, J.; Hudan, S.; Baxter, D. V.; deSouza, R. T.

2018-05-01

A novel approach for efficiently imaging objects with slow neutrons in two dimensions is realized. Neutron sensitivity is achieved by use of a boron doped microchannel plate (MCP). The resulting electron avalanche is further amplified with a Z-stack MCP before being sensed by two orthogonally oriented wire planes. Coupling of the wire planes to delay lines efficiently encodes the position information as a time difference. To determine the position resolution, slow neutrons were used to illuminate a Cd-mask placed directly in front of the detector. Peaks in the resulting spectrum exhibited an average peak width of 329 μm FWHM, corresponding to an average intrinsic resolution of 216 μm. The center region of the detector exhibits a significantly better spatial resolution with an intrinsic resolution of <100 μm observed.

Additive manufactured bipolar plate for high-efficiency hydrogen production in proton exchange membrane electrolyzer cells

DOE PAGES

Yang, Gaoqiang; Mo, Jingke; Kang, Zhenye; ...

2017-05-06

Additive manufacturing (AM) technology is capable of fast and low-cost prototyping from complex 3D digital models. To take advantage of this technology, a stainless steel (SS) plate with parallel flow field served as a combination of a cathode bipolar plate and a current distributor; it was fabricated using selective laser melting (SLM) techniques and investigated in a proton exchange membrane electrolyzer cell (PEMEC) in-situ for the first time. The experimental results show that the PEMEC with an AM SS cathode bipolar plate can achieve an excellent performance for hydrogen production for a voltage of 1.779 V and a current densitymore » of 2.0 A/cm 2. The AM SS cathode bipolar plate was also characterized by SEM and EDS, and the results show a uniform elemental distribution across the plate with very limited oxidization. As a result, this research demonstrates that AM method could be a route to aid cost-effective and rapid development of PEMECs.« less

A Study on Segmented Multiple-Step Forming of Doubly Curved Thick Plate by Reconfigurable Multi-Punch Dies

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

Ko, Young Ho; Han, Myoung Soo; Han, Jong Man

2007-05-17

Doubly curved thick plate forming in shipbuilding industries is currently performed by a thermal forming process, called as Line Heating by using gas flame torches. Due to the empirical manual work of it, the industries are eager for an alternative way to manufacture curved thick plates for ships. It was envisaged in this study to manufacture doubly curved thick plates by the multi-punch die forming. Experiments and finite element analyses were conducted to evaluate the feasibility of the reconfigurable discrete die forming to the thick plates. Single and segmented multiple step forming procedures were considered from both forming efficiency andmore » accuracy. Configuration of the multi-punch dies suitable for the segmented multiple step forming was also explored. As a result, Segmented multiple step forming with matched dies had a limited formability when the objective shapes become complicate, while a unmatched die configuration provided better possibility to manufacture large curved plates for ships.« less

The complex variable reproducing kernel particle method for bending problems of thin plates on elastic foundations

NASA Astrophysics Data System (ADS)

Chen, L.; Cheng, Y. M.

2018-07-01

In this paper, the complex variable reproducing kernel particle method (CVRKPM) for solving the bending problems of isotropic thin plates on elastic foundations is presented. In CVRKPM, one-dimensional basis function is used to obtain the shape function of a two-dimensional problem. CVRKPM is used to form the approximation function of the deflection of the thin plates resting on elastic foundation, the Galerkin weak form of thin plates on elastic foundation is employed to obtain the discretized system equations, the penalty method is used to apply the essential boundary conditions, and Winkler and Pasternak foundation models are used to consider the interface pressure between the plate and the foundation. Then the corresponding formulae of CVRKPM for thin plates on elastic foundations are presented in detail. Several numerical examples are given to discuss the efficiency and accuracy of CVRKPM in this paper, and the corresponding advantages of the present method are shown.

Additive manufactured bipolar plate for high-efficiency hydrogen production in proton exchange membrane electrolyzer cells

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

Yang, Gaoqiang; Mo, Jingke; Kang, Zhenye

Additive manufacturing (AM) technology is capable of fast and low-cost prototyping from complex 3D digital models. To take advantage of this technology, a stainless steel (SS) plate with parallel flow field served as a combination of a cathode bipolar plate and a current distributor; it was fabricated using selective laser melting (SLM) techniques and investigated in a proton exchange membrane electrolyzer cell (PEMEC) in-situ for the first time. The experimental results show that the PEMEC with an AM SS cathode bipolar plate can achieve an excellent performance for hydrogen production for a voltage of 1.779 V and a current densitymore » of 2.0 A/cm 2. The AM SS cathode bipolar plate was also characterized by SEM and EDS, and the results show a uniform elemental distribution across the plate with very limited oxidization. As a result, this research demonstrates that AM method could be a route to aid cost-effective and rapid development of PEMECs.« less

Lightweight, Rack-Mountable Composite Cold Plate/Shelves

NASA Technical Reports Server (NTRS)

Hurlbert, Kathryn M.; Ruemmele, Warren; Nguyen, Hai D.; Andish, Kambiz; McCalley, Sean

2004-01-01

Rack-mountable composite-material structural components that would serve as both shelves and cold plates for removing heat from electronic or other equipment mounted on the shelves have been proposed as lightweight alternatives to all-metal cold plate/shelves now in use. A proposed cold plate/shelf would include a highly thermally conductive face sheet containing oriented graphite fibers bonded to an aluminum honeycomb core, plus an extruded stainless-steel substructure containing optimized flow passages for a cooling fluid, and an inlet and outlet that could be connected to standard manifold sections. To maximize heat-transfer efficiency, the extruded stainless-steel substructure would be connected directly to the face sheet. On the basis of a tentative design, the proposed composite cold plate/shelf would weigh about 38 percent less than does an all-aluminum cold plate in use or planned for use in some spacecraft and possibly aircraft. Although weight is a primary consideration, the tentative design offers the additional benefit of reduction of thickness to half that of the all-aluminum version.

The acoustic power of a vibrating clamped circular plate revisited in the wide low frequency range using expansion into the radial polynomials.

PubMed

Rdzanek, Wojciech P

2016-06-01

This study deals with the classical problem of sound radiation of an excited clamped circular plate embedded into a flat rigid baffle. The system of the two coupled differential equations is solved, one for the excited and damped vibrations of the plate and the other one-the Helmholtz equation. An approach using the expansion into radial polynomials leads to results for the modal impedance coefficients useful for a comprehensive numerical analysis of sound radiation. The results obtained are accurate and efficient in a wide low frequency range and can easily be adopted for a simply supported circular plate. The fluid loading is included providing accurate results in resonance.

Scaling of surface-plasma reactors with a significantly increased energy density for NO conversion.

PubMed

Malik, Muhammad Arif; Xiao, Shu; Schoenbach, Karl H

2012-03-30

Comparative studies revealed that surface plasmas developing along a solid-gas interface are significantly more effective and energy efficient for remediation of toxic pollutants in air than conventional plasmas propagating in air. Scaling of the surface plasma reactors to large volumes by operating them in parallel suffers from a serious problem of adverse effects of the space charges generated at the dielectric surfaces of the neighboring discharge chambers. This study revealed that a conductive foil on the cathode potential placed between the dielectric plates as a shield not only decoupled the discharges, but also increased the electrical power deposited in the reactor by a factor of about forty over the electrical power level obtained without shielding and without loss of efficiency for NO removal. The shield had no negative effect on efficiency, which is verified by the fact that the energy costs for 50% NO removal were about 60 eV/molecule and the energy constant, k(E), was about 0.02 L/J in both the shielded and unshielded cases. Copyright © 2012 Elsevier B.V. All rights reserved.

Effect of the plate surface characteristics and gap height on yield stresses of a magnetorheological fluid

NASA Astrophysics Data System (ADS)

Jonkkari, I.; Kostamo, E.; Kostamo, J.; Syrjala, S.; Pietola, M.

2012-07-01

Effects of the plate material, surface roughness and measuring gap height on static and dynamic yield stresses of a magnetorheological (MR) fluid were investigated with a commercial plate-plate magnetorheometer. Magnetic and non-magnetic plates with smooth (Ra ˜ 0.3 μm) and rough (Ra ˜ 10 μm) surface finishes were used. It was shown by Hall probe measurements and finite element simulations that the use of magnetic plates or higher gap heights increases the level of magnetic flux density and changes the shape of the radial flux density profile. The yield stress increase caused by these factors was determined and subtracted from the measured values in order to examine only the effect of the wall characteristics or the gap height. Roughening of the surfaces offered a significant increase in the yield stresses for non-magnetic plates. With magnetic plates the yield stresses were higher to start with, but roughening did not increase them further. A significant part of the difference in measured stresses between rough non-magnetic and magnetic plates was caused by changes in magnetic flux density rather than by better contact of the particles to the plate surfaces. In a similar manner, an increase in gap height from 0.25 to 1.00 mm can lead to over 20% increase in measured stresses due to changes in the flux density profile. When these changes were compensated the dynamic yield stresses generally remained independent of the gap height, even in the cases where it was obvious that the wall slip was present. This suggests that with MR fluids the wall slip cannot be reliably detected by comparison of flow curves measured at different gap heights.

Biomechanical and biological aspects of defect treatment in fractures using helical plates.

PubMed

Perren, S M; Regazzoni, P; Fernandez, A A D

2014-01-01

The clinical case of figure 1 through figure 11 shows a series of impressive failures of plate fixation. The plates were repeatedly applied bridging a comminuted bone segment in a heavy patient. The biomechanical analysis elaborates why this happened and proposes an unconventional procedure to prevent this failure with a minimally invasive procedure. A plate bridging an open gap or a defect in a long bone diaphysis is exposed to full functional load. According to clinical observations such plate application often fails even without external load such as weight bearing. The plate risks to break through fatigue when exposed during a long time to cyclic loading. This type of failure has been observed even with broad plates as well in femoral as in tibiae. The first option to avoid such failure consists in protecting the plate by installing load sharing between plate and either bone or an additional implant. This reduces the load carried by the plate to a safe level. Load sharing with bone may be installed at surgery by establishing solid mechanical bridge between the two main fragments of the fractured bone. The optimal load sharing relies on a solid compressed contact between the main fragments. It can be established because the bone is able to take a large load which results in optimal protection of the plate. In the case of an extended comminuted bone segment it may be very difficult, traumatizing and inefficient to reconstruct the bone. In the present case it was impossible to establish load sharing through the bone. The second option protecting the plate is provided by callus bridging of the gap or defect. The formation of a solid callus bridge takes time but the fatigue failure of the plate also takes time. Therefore, the callus bridge may prevent a late fatigue failure. The surgeon may select one of several options: - Replacing the lack of bone support using a second plate which immediately alleviates plate loading. The drawback of application of a second conventional plate is the extent of surgical trauma at the critical site of healing. - Shingling and/or applying an autologous cancellous bone graft: This procedure provides initially no relevant load sharing but will do so after a couple of weeks. The mechanical coupling of the comparably soft graft and the main fracture fragments presents little problems. Applying a cortical bone graft: Such a graft does provide initial only small load sharing and does a less good job inducing callus than a cancellous graft. Furthermore, the coupling by callus between a somewhat rigid bone graft and the mobile main fracture fragments requires a solid maintained contact. If the cortical graft is fixed using implants with small contact area to the graft such as screws or cerclage loops, the local stress may be critical and the graft may break. When the cortical graft is fixed with cerclage wires the procedure must take into account the limited strength of the individual cerclage. Therefore multiple and well-spaced cerclages are required and may lead to success especially if an intramedullary component of the implant contributes to protection (6). The degree of unloading depends apparently on the stiffness of the material of the protecting splint. Though, more important is the effect of the dimensions of the splint. While titanium as a material is about 50% less stiff than steel, the thickness of the implant changes the stiffness with the third power. That is doubling the thickness results in eightfold increased stiffness. When considering the unloading by application of a second plate the leverage of the second plate plays an important role. The larger the distance between the axis of bending and the second implant the larger the protecting effect. The helical plate (2, 3, 7) as introduced by A.A.D. Fernandez offers biological and mechanical advantages. It can be applied without touching the fracture site maintaining the critical biology intact and provides mechanically efficient unloading. Its application is fairly simple: The helical plate is modified conventional long and small plate that is twisted between its ends about 90 degrees. The twist is applied using "bending irons" (4, 5, 8) whereby the force required is small and the exact degree of twist is not critical. Therefore the twist is applicable operating bending irons by hand. Assuming a situation where a plate bridging a defect or non-union has failed the broken plate is replaced by a similar implant: At the distal end of the bone fracture and opposite to the surgical approach a small incision allows to slide in the helical plate in such a way that proximally the plate ends on the same side of the limb as the replaced plate. Ideally the two plate ends meet and the application of the helical plate does not ask for an additional surgical exposure at this location. Otherwise a small minimally invasive exposure is required. The helical plate is then fixed to the main bone fragments using a couple of locked screws. The following case demonstrates the use and efficiency of the helical plate saving a situation where multiple attempts using conventional plates had failed. The successful final treatment of this case was performed by A. A. D. Fernandez.

Symbolic manipulation techniques for vibration analysis of laminated elliptic plates

NASA Technical Reports Server (NTRS)

Andersen, C. M.; Noor, A. K.

1977-01-01

A computational scheme is presented for the free vibration analysis of laminated composite elliptic plates. The scheme is based on Hamilton's principle, the Rayleigh-Ritz technique and symmetry considerations and is implemented with the aid of the MACSYMA symbolic manipulation system. The MACYSMA system, through differentiation, integration, and simplification of analytic expressions, produces highly-efficient FORTRAN code for the evaluation of the stiffness and mass coefficients. Multiple use is made of this code to obtain not only the frequencies and mode shapes of the plate, but also the derivatives of the frequencies with respect to various material and geometric parameters.

A Surface Pattern on MALDI Steel Plate for One-Step In-Situ Self-Desalting and Enrichment of Peptides/Proteins

NASA Astrophysics Data System (ADS)

Wang, Sheng; Xiao, Chunsheng; Li, Ying; Ling, Ling; Chen, Xuesi; Guo, Xinhua

2017-03-01

We report a novel strategy to achieve simultaneous one-step in-situ self-desalting and enrichment (OISE) of peptides/proteins on a facilely fabricated patterned MALDI steel plate with a circular paraffin-steel-polystyrene structure. The OISE plate could efficiently segregate salts from both analytes and matrices while retaining both analyte and matrix concentrate, and facilitating them to form homogeneous co-crystals on the centrally located polystyrene pattern. With the OISE plate, high quality and reproducible spectra could be obtained for low abundance peptides even in the presence of high salt concentrations (200 mM NH4HCO3, 1 M NaCl, or 400 mM urea). Using this strategy, a significant sensitivity enhancement was gained over traditional MALDI plate. The practical utility of this method was further demonstrated by the successful profiling of BSA digests and human serum.

Fractional-order positive position feedback compensator for active vibration control of a smart composite plate

NASA Astrophysics Data System (ADS)

Marinangeli, L.; Alijani, F.; HosseinNia, S. Hassan

2018-01-01

In this paper, Active Vibration Control (AVC) of a rectangular carbon fibre composite plate with free edges is presented. The plate is subjected to out-of-plane excitation by a modal vibration exciter and controlled by Macro Fibre Composite (MFC) transducers. Vibration measurements are performed by using a Laser Doppler Vibrometer (LDV) system. A fractional-order Positive Position Feedback (PPF) compensator is proposed, implemented and compared to the standard integer-order PPF. MFC actuator and sensor are positioned on the plate based on maximal modal strain criterion, so as to control the second natural mode of the plate. Both integer and fractional-order PPF allowed for the effective control of the second mode of vibration. However, the newly proposed fractional-order controller is found to be more efficient in achieving the same performance with less actuation voltage. Moreover, it shows promising performance in reducing spillover effect due to uncontrolled modes.

A 2D Daubechies finite wavelet domain method for transient wave response analysis in shear deformable laminated composite plates

NASA Astrophysics Data System (ADS)

Nastos, C. V.; Theodosiou, T. C.; Rekatsinas, C. S.; Saravanos, D. A.

2018-03-01

An efficient numerical method is developed for the simulation of dynamic response and the prediction of the wave propagation in composite plate structures. The method is termed finite wavelet domain method and takes advantage of the outstanding properties of compactly supported 2D Daubechies wavelet scaling functions for the spatial interpolation of displacements in a finite domain of a plate structure. The development of the 2D wavelet element, based on the first order shear deformation laminated plate theory is described and equivalent stiffness, mass matrices and force vectors are calculated and synthesized in the wavelet domain. The transient response is predicted using the explicit central difference time integration scheme. Numerical results for the simulation of wave propagation in isotropic, quasi-isotropic and cross-ply laminated plates are presented and demonstrate the high spatial convergence and problem size reduction obtained by the present method.

The effect of papaine on the time course of the end-plate current.

PubMed

Humar, M; Kordas, M; Melik, Z

1980-07-01

Papaine is known to detach cholinesterases from the synaptic cleft. It could be expected that this would result in an increase of the amplitude and half-time of the end-plate current. Thus, the effect of papaine on the end-plate current. Thus, the effect of papaine on the end-plate current should be similar to the effect of anticholinesterase methanesulfonylfluoride. The end-plate current was recorded in frog skeletal muscle at various levels of membrane potential, before and after papaine was added to the bath. The effect of papaine was an increase of the half-time of the end-plate current, similarly as after treatment of the muscle by methanesulfonylfluoride. It seems that both papaine and methanesulfonylfluoride have a similar mechanism of action. In either experimental condition hydrolysis of transmitter is decreased or abolished, which results in an increase of the half-time of the end-plate current.

The economic payoff for a state-of-the-art high-efficiency flat-plate crystalline silicon solar cell technology

NASA Technical Reports Server (NTRS)

Bickler, Donald B.; Callaghan, W. T.

1987-01-01

In 1986 during the flat-plate solar array project, silicon solar cells 4.0 sq cm in area were fabricated at the Jet Propulsion Laboratory (JPL) with a conversion efficiency of 20.1 percent (AM1.5-global). Sixteen cells were processed with efficiencies measuring 19.5 percent (AM1.5 global) or better. These cells were produced using refined versions of conventional processing methods, aside from certain advanced techniques that bring about a significant reduction in a major mechanism (surface recombination) that limits cell efficiency. Wacker Siltronic p-type float-zone 0.18-ohm-cm wafers were used. Conversion efficiencies in this range have previously been reported by other researchers, but generally on much smaller (0.5 vs. 4.0 cm) devices which have undergone sophisticated and costly processing steps. An economic analysis is presented of the potential payoffs for this approach, using the Solar Array Manufacturing Industry Costing Standards (SAMICS) methodology. The process sequence used and the assumptions made for capturing the economies of scale are presented.

High-efficiency directional backlight design for an automotive display.

PubMed

Chen, Bo-Tsuen; Pan, Jui-Wen

2018-06-01

We propose a high-efficiency directional backlight module (DBM) for automotive display applications. The DBM is composed of light sources, a light guide plate (LGP), and an optically patterned plate (OPP). The LGP has a collimator on the input surface that serves to control the angle of the light emitted to be in the horizontal direction. The OPP has an inverse prism to adjust the light emission angle in the vertical direction. The DBM has a simple structure and high optical efficiency. Compared with conventional backlight systems, the DBM has higher optical efficiency and a suitable viewing angle. This is an improvement in normalized on-axis luminous intensity of 2.6 times and a twofold improvement in optical efficiency. The viewing angles are 100° in the horizontal direction and 35° in the vertical direction. The angle of the half-luminous intensity is 72° in the horizontal direction and 20° in the vertical direction. The uniformity of the illuminance reaches 82%. The DBM is suitable for use in the center information displays of automobiles.

Degradation in the efficiency of glass Resistive Plate Chambers operated without external gas supply

NASA Astrophysics Data System (ADS)

Baesso, P.; Cussans, D.; Thomay, C.; Velthuis, J.; Burns, J.; Quillin, S.; Stapleton, M.; Steer, C.

2015-06-01

Resistive plate chambers (RPC) are particle detectors commonly used by the high energy physics community. Their normal operation requires a constant flow of gas mixture to prevent self-poisoning which reduces the chamber's capability to detect particles. We studied how quickly the efficiency of two RPCs drops when operated in sealed mode, i.e. without refreshing the gas mixture. The test aim is to determine how RPCs could be used as particle detectors in non-laboratory applications, such as those exploiting muon tomography for geological imaging or homeland security. The two sealed RPCs were operated in proportional mode for a period of more than three months, and their efficiencies were recorded continuously and analysed in 8-hours intervals. The results show that the efficiency drops on average by 0.79 ± 0.01 % every 24 hours of operation and returns close to the initial value after purging the old gas mixture and flushing the chambers with fresh gas.

A simple agar plate preparation for effective transfer of Ureaplasma colonies onto nitrocellulose membranes for colony immunoblotting.

PubMed

Zimmerman, Carl-Ulrich R; Stiedl, Thomas; Spergser, Joachim; Rosengarten, Renate

2014-09-01

A simple method for preparing agar plates is presented, which allows an efficient transfer of Ureaplasma colonies to nitrocellulose membranes for subsequent immunological detection. This simple and reproducible procedure was used to demonstrate antigenic variation in the phase-variable mba-locus of Ureaplasma parvum serovar 3. Copyright © 2014 Elsevier B.V. All rights reserved.

US - European Workshop on Thermal Waste Treatment for Naval Vessels

DTIC Science & Technology

1997-01-01

REGULATION 2 Definitions REGULATION 3.: GENERAL EXCEPTIONS REGULATION 4.: EQUIVALENTS REGULATION 5.: SURVEYS AND INSPECTIONS REUGLATION 6.: ISSUE OF...item Shampoo /Lotion PAPER OR REFILLABLE DISPENSERS Plates. Plastic coated PAPER PLATES Coffe cups. styrofoam PAPER CUPS Plastic clear portion cups...shipboard operation and has demonstrated that it can efficiently destroy liquid wastes when properly maintained and operated. A survey of marine and

Novel Waveguide Structures in the Terahertz Frequency Range

NASA Astrophysics Data System (ADS)

Mbonye, Marx

Over the last decade, considerable research interest has peaked in realizing an efficient Terahertz (THz) waveguide for potential applications in imaging, sensing, and communications applications. Two of the promising candidates are the two-wire waveguide and the parallel-plate waveguide (PPWG). I present theoretical and experimental evidence that show that the two-wire waveguide supports low loss terahertz pulse propagation, and illustrate that the mode pattern at the end of the waveguide resembles that of a dipole. In comparison to the weakly guided Sommerfeld wave of a single wire waveguide, this two-wire structure exhibits much lower bending losses. I also observe that a commercial 300-Ohm two-wire TVantenna cable can be used for guiding frequency components of up to 0.2 THz, although these cables are generally designed to operate only up to about 800 MHz. The parallel-plate waveguide is another promising candidate that would make an efficient THz waveguide, since it has relatively low Ohmic losses. The transverse electromagnetic mode (TEM) of this waveguide has been generally preferred since it has no cutoff frequency, and therefore no group velocity dispersion. Utilizing this TEM mode, I study the reflection of THz radiation at the end of a PPWG, due to the impedance mismatch between the propagating transverse-electromagnetic mode and the free-space background. I find that for a PPWG with uniformly spaced plates, the reflection coefficient at the output face increases as the plate separation decreases, consistent with predictions by early low frequency ray optical theory. I observe this same trend in tapered PPWGs, when the input separation is fixed, and the output separation is varied. In another study, I investigate how to minimize diffraction losses in PPWGs by using plates with slightly concave surfaces. Using a simple "bouncing plane wave" analysis, I demonstrate how to determine an ideal radius of curvature for a waveguide operating at a given THz frequency. I perform a detailed experimental and simulation study that illustrates, for a waveguide with a plate separation of 1 cm, one can inhibit the diffraction around a frequency of 0.1 THz, when the surface has a curvature of 6.7 cm. Using much longer PPWGs (about 170cm), I reliably measure the overall losses in a PPWG with a radius of curvature of R=6.7 cm, and find it to be less than 1db/m around the design frequency (of 0.1 THz). This is very close to the lowest achieved loss to date with any terahertz waveguide.

A Multi-scale Refined Zigzag Theory for Multilayered Composite and Sandwich Plates with Improved Transverse Shear Stresses

NASA Technical Reports Server (NTRS)

Iurlaro, Luigi; Gherlone, Marco; Di Sciuva, Marco; Tessler, Alexander

2013-01-01

The Refined Zigzag Theory (RZT) enables accurate predictions of the in-plane displacements, strains, and stresses. The transverse shear stresses obtained from constitutive equations are layer-wise constant. Although these transverse shear stresses are generally accurate in the average, layer-wise sense, they are nevertheless discontinuous at layer interfaces, and thus they violate the requisite interlaminar continuity of transverse stresses. Recently, Tessler applied Reissner's mixed variational theorem and RZT kinematic assumptions to derive an accurate and efficient shear-deformation theory for homogeneous, laminated composite, and sandwich beams, called RZT(m), where "m" stands for "mixed". Herein, the RZT(m) for beams is extended to plate analysis, where two alternative assumptions for the transverse shear stresses field are examined: the first follows Tessler's formulation, whereas the second is based on Murakami's polynomial approach. Results for elasto-static simply supported and cantilever plates demonstrate that Tessler's formulation results in a powerful and efficient structural theory that is well-suited for the analysis of multilayered composite and sandwich panels.

Investigation of focusing and correcting aberrations with binary amplitude and polarization modulation

DOE PAGES

Fiala, Peter; Li, Yunqi; Dorrer, Christophe

2018-01-29

Here, we investigate the focusing and correcting wavefront aberration of an optical wave using binary amplitude and polarization modulation. Focusing is performed by selectively modulating the field in different zones of the pupil to obtain on-axis constructive interference at a given distance. The conventional Soret zone plate (binary amplitude profile) is expanded to a polarization Soret zone plate with twice the focusing efficiency. Binary pixelated devices that approximate the sinusoidal transmission profile of a Gabor zone plate by spatial dithering are also investigated with amplitude and polarization modulation. Wavefront aberrations are corrected by modulation of the field in the pupilmore » plane to prevent destructive interference in the focal plane of an ideal focusing element. Polarization modulation improves the efficiency obtained by amplitude-only modulation, with a gain that depends on the aberration. Experimental results obtained with Cr-on-glass devices for amplitude modulation and liquid crystal devices operating in the Mauguin condition for polarization modulation are in very good agreement with simulations.« less

Efficient electron open boundaries for simulating electrochemical cells

NASA Astrophysics Data System (ADS)

Zauchner, Mario G.; Horsfield, Andrew P.; Todorov, Tchavdar N.

2018-01-01

Nonequilibrium electrochemistry raises new challenges for atomistic simulation: we need to perform molecular dynamics for the nuclear degrees of freedom with an explicit description of the electrons, which in turn must be free to enter and leave the computational cell. Here we present a limiting form for electron open boundaries that we expect to apply when the magnitude of the electric current is determined by the drift and diffusion of ions in a solution and which is sufficiently computationally efficient to be used with molecular dynamics. We present tight-binding simulations of a parallel-plate capacitor with nothing, a dimer, or an atomic wire situated in the space between the plates. These simulations demonstrate that this scheme can be used to perform molecular dynamics simulations when there is an applied bias between two metal plates with, at most, weak electronic coupling between them. This simple system captures some of the essential features of an electrochemical cell, suggesting this approach might be suitable for simulations of electrochemical cells out of equilibrium.

Super-low-frequency wireless power transfer with lightweight coils for passing through a stainless steel plate

NASA Astrophysics Data System (ADS)

Ishida, Hiroki; Kyoden, Tomoaki; Furukawa, Hiroto

2018-03-01

To achieve wireless power transfer (WPT) through a stainless-steel plate, a super-low frequency (SLF) was used as a resonance frequency. In our previous study of SLF-WPT, heavy coils were prepared. In this study, we designed lightweight coils using a WPT simulator that we developed previously. As a result, the weight was reduced to 1.69 kg from 11.9 kg, the previous coil weight. At a resonance frequency of 400 Hz, the transmission efficiency and output power of advanced SLF-WPT reached 91% and 426 W, respectively, over a transmission distance of 30 mm. Furthermore, 80% efficiency and 317 W output were achieved when transmitting power through a 1 mm-thick stainless-steel plate. This performance is much better than that in previous reports. We show using both calculations and experimental results that a power-to-weight ratio of 252 W/kg is possible even when using a 400 Hz power supply frequency.

Super-low-frequency wireless power transfer with lightweight coils for passing through a stainless steel plate.

PubMed

Ishida, Hiroki; Kyoden, Tomoaki; Furukawa, Hiroto

2018-03-01

To achieve wireless power transfer (WPT) through a stainless-steel plate, a super-low frequency (SLF) was used as a resonance frequency. In our previous study of SLF-WPT, heavy coils were prepared. In this study, we designed lightweight coils using a WPT simulator that we developed previously. As a result, the weight was reduced to 1.69 kg from 11.9 kg, the previous coil weight. At a resonance frequency of 400 Hz, the transmission efficiency and output power of advanced SLF-WPT reached 91% and 426 W, respectively, over a transmission distance of 30 mm. Furthermore, 80% efficiency and 317 W output were achieved when transmitting power through a 1 mm-thick stainless-steel plate. This performance is much better than that in previous reports. We show using both calculations and experimental results that a power-to-weight ratio of 252 W/kg is possible even when using a 400 Hz power supply frequency.

Investigation of focusing and correcting aberrations with binary amplitude and polarization modulation

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

Fiala, Peter; Li, Yunqi; Dorrer, Christophe

Here, we investigate the focusing and correcting wavefront aberration of an optical wave using binary amplitude and polarization modulation. Focusing is performed by selectively modulating the field in different zones of the pupil to obtain on-axis constructive interference at a given distance. The conventional Soret zone plate (binary amplitude profile) is expanded to a polarization Soret zone plate with twice the focusing efficiency. Binary pixelated devices that approximate the sinusoidal transmission profile of a Gabor zone plate by spatial dithering are also investigated with amplitude and polarization modulation. Wavefront aberrations are corrected by modulation of the field in the pupilmore » plane to prevent destructive interference in the focal plane of an ideal focusing element. Polarization modulation improves the efficiency obtained by amplitude-only modulation, with a gain that depends on the aberration. Experimental results obtained with Cr-on-glass devices for amplitude modulation and liquid crystal devices operating in the Mauguin condition for polarization modulation are in very good agreement with simulations.« less

Silicon Nitride Plates for Turbine Blade Application: FEA and NDE Assessment

NASA Technical Reports Server (NTRS)

Abdul-Aziz, Ali; Baaklini, George Y.; Bhatt, Ramakrishna T.

2001-01-01

Engine manufacturers are continually attempting to improve the performance and the overall efficiency of internal combustion engines. The thermal efficiency is typically improved by raising the operating temperature of essential engine components in the combustion area. This reduces the heat loss to a cooling system and allows a greater portion of the heat to be used for propulsion. Further improvements can be achieved by diverting part of the air from the compressor, which would have been used in the combustor for combustion purposes, into the turbine components. Such a process is called active cooling. Increasing the operating temperature, decreasing the cooling air, or both can improve the efficiency of the engine. Furthermore, lightweight, strong, tough hightemperature materials are required to complement efficiency improvement for nextgeneration gas turbine engines that can operate with minimum cooling. Because of their low-density, high-temperature strength, and thermal conductivity, ceramics are being investigated as potential materials for replacing ordinary metals that are currently used for engine hot section components. Ceramic structures can withstand higher operating temperatures and other harsh environmental factors. In addition, their low densities relative to metals helps condense component mass (ref. 1). The objectives of this program at the NASA Glenn Research Center are to develop manufacturing technology, a thermal barrier coating/environmental barrier coating (TBC/EBC), and an analytical modeling capability to predict thermomechanical stresses, and to do minimal burner rig tests of silicon nitride (Si3N4) and SiC/SiC turbine nozzle vanes under simulated engine conditions. Furthermore, and in support of the latter objectives, an optimization exercise using finite element analysis and nondestructive evaluation (NDE) was carried out to characterize and evaluate silicon nitride plates with cooling channels.

Suction performance and internal flow of a 2-bladed helical inducer with inlet asymmetric plate

NASA Astrophysics Data System (ADS)

Watanabe, S.; Uchinono, Y.; Ishizaka, K.; Furukawa, A.; Kim, J.-H.

2013-10-01

It has been found in our past studies that the installation of asymmetric plate at the inlet of inducer is effective for the suppression of cavitation surge phenomenon. In the present study, the suction performance of 2-bladed helical inducer with an inlet asymmetric plate is experimentally investigated. It is observed that the suction performance in large flow rate conditions is not significantly influenced by the asymmetric plate, whereas the head of inducer with the asymmetric plate increases just before the head breakdown in partial flow conditions. To understand the mechanism of this additional head, the flow measurements and the numerical simulations are carried out. It is found that the circumferential component of absolute velocity at the exit of inducer slightly increases with the development of cavitation in both cases with and without the inlet asymmetric plate, indicating the increase of the theoretical head. The theoretical head increase with the inlet asymmetric plate is also confirmed by the unsteady numerical simulations, suggesting that the additional head is achieved through the increase of the theoretical head with the change of the exiting flow from the inducer associated with some amount of cavitation.

Spectroscopic observations of comets

NASA Technical Reports Server (NTRS)

1982-01-01

Development of a spectrograph using a microchannel plate intensifier for observing faint comets is described. The spectrograph is capable of obtaining useful spectra of objects as faint as M(2) = 18. The increased guiding efficiency achieved by the optical coupling of the ISIT vidicon of the 154 cm telescope has resulted in a better signal to noise ratio. The ability to take a direct image of the comet aids in the interpretation of the spatial profile of the emissions. Spectra of comets Schwassmann-Wachmann 1, Bradfield, Encke, Tuttle, and Stephen-Oterma are discussed.

Micro-Welding of Copper Plate by Frequency Doubled Diode Pumped Pulsed Nd:YAG Laser

NASA Astrophysics Data System (ADS)

Nakashiba, Shin-Ichi; Okamoto, Yasuhiro; Sakagawa, Tomokazu; Takai, Sunao; Okada, Akira

A pulsed laser of 532 nm wavelength with ms range pulse duration was newly developed by second harmonic generation of diode pumped pulsed Nd:YAG laser. High electro-optical conversion efficiency more than 13% could be achieved, and 1.5 kW peak power green laser pulse was put in optical fiber of 100 μm in diameter. In micro- welding of 1.0 mm thickness copper plate, a keyhole welding was successfully performed by 1.0 kW peak power at spot diameter less than 200 μm. The frequency doubled pulsed laser improved the processing efficiency of copper welding, and narrow and deep weld bead was stably obtained.

Probabilistic structural analysis using a general purpose finite element program

NASA Astrophysics Data System (ADS)

Riha, D. S.; Millwater, H. R.; Thacker, B. H.

1992-07-01

This paper presents an accurate and efficient method to predict the probabilistic response for structural response quantities, such as stress, displacement, natural frequencies, and buckling loads, by combining the capabilities of MSC/NASTRAN, including design sensitivity analysis and fast probability integration. Two probabilistic structural analysis examples have been performed and verified by comparison with Monte Carlo simulation of the analytical solution. The first example consists of a cantilevered plate with several point loads. The second example is a probabilistic buckling analysis of a simply supported composite plate under in-plane loading. The coupling of MSC/NASTRAN and fast probability integration is shown to be orders of magnitude more efficient than Monte Carlo simulation with excellent accuracy.

Full title: Biomechanical comparison between stainless steel, titanium and carbon-fiber reinforced polyetheretherketone volar locking plates for distal radius fractures.

PubMed

Mugnai, Raffaele; Tarallo, Luigi; Capra, Francesco; Catani, Fabio

2018-05-25

As the popularity of volar locked plate fixation for distal radius fractures has increased, so have the number and variety of implants, including variations in plate design, the size and angle of the screws, the locking screw mechanism, and the material of the plates. carbon-fiber reinforced polyetheretherketone (CFR-PEEK) plate features similar biomechanical properties to metallic plates, representing, therefore, an optimal alternative for the treatment of distal radius fractures. three different materials-composed plates were evaluated: stainless steel volar lateral column (Zimmer); titanium DVR (Hand Innovations); CFR-PEEK DiPHOS-RM (Lima Corporate). Six plates for each type were implanted in sawbones and an extra-articular rectangular osteotomy was created. Three plates for each material were tested for load to failure and bending stiffness in axial compression. Moreover, 3 constructs for each plate were evaluated after dynamically loading for 6000 cycles of fatigue. the mean bending stiffness pre-fatigue was significantly higher for the stainless steel plate. The titanium plate yielded the higher load to failure both pre and post fatigue. After cyclic loading, the bending stiffness increased by a mean of 24% for the stainless steel plate; 33% for the titanium; and 17% for the CFR-PEEK plate. The mean load to failure post-fatigue increased by a mean of 10% for the stainless steel and 14% for CFR-PEEK plates, whereas it decreased (-16%) for the titanium plate. Statistical analysis between groups reported significant values (p <.001) for all comparisons except for Hand Innovations vs. Zimmer bending stiffness post fatigue (p = .197). the significant higher load to failure of the titanium plate, makes it indicated for patients with higher functional requirements or at higher risk of trauma in the post-operative period. The CFR-PEEK plate showed material-specific disadvantages, represented by little tolerance to plastic deformation, and lower load to failure. N/A. Copyright © 2018. Published by Elsevier Masson SAS.

Comparison of submuscular and open plating of pediatric femur fractures: a retrospective review.

PubMed

Abbott, Matthew D; Loder, Randall T; Anglen, Jeffrey O

2013-01-01

Plate osteosynthesis is an accepted method of treatment of pediatric femur fractures. Historically, open plating has been used. Submuscular bridge plating has gained recent popularity due to the theoretical advantages of decreased operative time, decreased blood loss, and decreased risk for infection. The purpose of this study was to compare submuscular bridge plating to open plating of pediatric femur fractures. We retrospectively reviewed 79 patients (80 treated femur fractures) between 1999 and 2011 that underwent either open plating (58 femur fractures) or submuscular bridge plating (22 femur fractures). The outcome measures evaluated were operative time, estimated blood loss, malunion, leg length discrepancy, time to union, infection, unplanned return to the operating room, and length of hospital stay after surgery. Among our outcome measures, there was no difference between the 2 groups in terms of operative time, leg length discrepancy, time to union, infection, or length of hospital stay after surgery. There was greater estimated blood loss in the open plating group (P≤0.0001) and greater rotational asymmetry in the submuscular bridge plating group (P=0.005). There was a trend of increased unplanned return to the operating room in the open plating group (5/58 vs. 0/22) although not statistically significant (P=0.32). Submuscular bridge plating and open plating seem to be equally viable options for the management of pediatric diaphyseal femur fractures. In this study, open plating had an increase in estimated blood loss and a trend of more unplanned returns to the operating room, whereas submuscular bridge plating had an increase in asymptomatic rotational asymmetry. Further larger, prospective, randomized studies are necessary to further evaluate these operative techniques. Therapeutic Level III.

Double-Sided Single-Pass Submerged Arc Welding for 2205 Duplex Stainless Steel

NASA Astrophysics Data System (ADS)

Luo, Jian; Yuan, Yi; Wang, Xiaoming; Yao, Zongxiang

2013-09-01

The duplex stainless steel (DSS), which combines the characteristics of ferritic steel and austenitic steel, is used widely. The submerged arc welding (SAW) method is usually applied to join thick plates of DSS. However, an effective welding procedure is needed in order to obtain ideal DSS welds with an appropriate proportion of ferrite (δ) and austenite (γ) in the weld zone, particularly in the melted zone and heat-affected zone. This study evaluated the effectiveness of a high efficiency double-sided single-pass (DSSP) SAW joining method for thick DSS plates. The effectiveness of the converse welding procedure, characterizations of weld zone, and mechanical properties of welded joint are analyzed. The results show an increasing appearance and continuous distribution feature of the σ phase in the fusion zone of the leading welded seam. The converse welding procedure promotes the σ phase to precipitate in the fusion zone of leading welded side. The microhardness appears to significantly increase in the center of leading welded side. Ductile fracture mode is observed in the weld zone. A mixture fracture feature appears with a shear lip and tears in the fusion zone near the fusion line. The ductility, plasticity, and microhardness of the joints have a significant relationship with σ phase and heat treatment effect influenced by the converse welding step. An available heat input controlling technology of the DSSP formation method is discussed for SAW of thick DSS plates.

The Efficiency of UVC Radiation in the Inactivation of
Listeria monocytogenes on Beef-Agar Food Models.

PubMed

Hamidi-Oskouei, Amir M; James, Christian; James, Stephen

2015-06-01

The aim of this study is to evaluate the effect of meat content and surface smoothness on the deactivation of Listeria monocytogenes in beef-agar food models achieved by shortwave ultraviolet (UVC) light. Food models with various meat contents were made using chopped beef slices and agar solution. Prepared models together with a Listeria selective agar (LSA) plate and a slice of cooked beef were inoculated with L. monocytogenes and then exposed to UVC light. Population of Listeria reduced to below the level of detection on the LSA plates. As the content of beef in the beef-agar models increased, more L. monocytogenes cells survived. Survival was greatest on the treated cooked slice of beef. To better understand the effect of surface irregularities, a white light interferometer was used to analyse the surface smoothness of beef-agar media and LSA plates. No correlation was observed between the surface roughness of seven out of nine types of produced beef-agar media and the degree of inactivation resulting from UVC radiation at the given dose, whereas, less bacterial cells were killed as beef content of the food models increased. The findings of the current study show that the chemical composition of the treated sample also plays an important role in pathogen resistance and survival, meaning that two samples with similar surface irregularities but different chemical composition might produce very different inactivation results when exposed to UVC light.

The Efficiency of UVC Radiation in the Inactivation of
Listeria monocytogenes on Beef-Agar Food Models

PubMed Central

James, Christian; James, Stephen

2015-01-01

Summary The aim of this study is to evaluate the effect of meat content and surface smoothness on the deactivation of Listeria monocytogenes in beef-agar food models achieved by shortwave ultraviolet (UVC) light. Food models with various meat contents were made using chopped beef slices and agar solution. Prepared models together with a Listeria selective agar (LSA) plate and a slice of cooked beef were inoculated with L. monocytogenes and then exposed to UVC light. Population of Listeria reduced to below the level of detection on the LSA plates. As the content of beef in the beef-agar models increased, more L. monocytogenes cells survived. Survival was greatest on the treated cooked slice of beef. To better understand the effect of surface irregularities, a white light interferometer was used to analyse the surface smoothness of beef-agar media and LSA plates. No correlation was observed between the surface roughness of seven out of nine types of produced beef-agar media and the degree of inactivation resulting from UVC radiation at the given dose, whereas, less bacterial cells were killed as beef content of the food models increased. The findings of the current study show that the chemical composition of the treated sample also plays an important role in pathogen resistance and survival, meaning that two samples with similar surface irregularities but different chemical composition might produce very different inactivation results when exposed to UVC light. PMID:27904353

Target Plate Material Influence on Fullerene-C60 Laser Desorption/Ionization Efficiency.

PubMed

Zeegers, Guido P; Günthardt, Barbara F; Zenobi, Renato

2016-04-01

Systematic laser desorption/ionization (LDI) experiments of fullerene-C60 on a wide range of target plate materials were conducted to gain insight into the initial ion formation in matrix-assisted laser desorption/ionization (MALDI) mass spectrometry. The positive and negative ion signal intensities of precursor, fragment, and cluster ions were monitored, varying both the laser fluence (0-3.53 Jcm(-2)) and the ion extraction delay time (0-950 ns). The resulting species-specific ion signal intensities are an indication for the ionization mechanisms that contribute to LDI and the time frames in which they operate, providing insight in the (MA)LDI primary ionization. An increasing electrical resistivity of the target plate material increases the fullerene-C60 precursor and fragment anion signal intensity. Inconel 625 and Ti90/Al6/V4, both highly electrically resistive, provide the highest anion signal intensities, exceeding the cation signal intensity by a factor ~1.4 for the latter. We present a mechanism based on transient electrical field strength reduction to explain this trend. Fullerene-C60 cluster anion formation is negligible, which could be due to the high extraction potential. Cluster cations, however, are readily formed, although for high laser fluences, the preferred channel is formation of precursor and fragment cations. Ion signal intensity depends greatly on the choice of substrate material, and careful substrate selection could, therefore, allow for more sensitive (MA)LDI measurements. Graphical Abstract ᅟ.

Are terrestrial plumes from motionless plates analogues to Martian plumes feeding the giant shield volcanoes?

NASA Astrophysics Data System (ADS)

Meyzen, Christine; Massironi, Matteo; Pozzobon, Riccardo; Dal Zilio, Luca

2014-05-01

The near "one-plate" planet evolution of Mars has led to the edification of long-lasting giant shied volcanoes. Unlike the Earth, Mars would have been a transient convecting planet, where plate tectonic would have possibly acted only during the first hundreds of million years of its history. On Earth, where plate tectonic is active, most of them are regenerated and recycled through convection. However, the Nubian and Antarctic plates could be considered as poorly mobile surfaces of various thicknesses that are acting as conductive lids on top of Earth's deeper convective system. In these environments, volcanoes do not show any linear age progression at least for the last 30 Ma, but constitute the sites of persistent, focused long-term magmatic activity, rather than a chain of volcanoes as observed in fast-moving plate plume environments. Here, the near stationary absolute plate motion probably exerts a primary control on volcanic processes, and more specifically, on the melting ones. The residual depleted mantle, that is left behind by the melting processes, cannot be swept away from the melting locus. Over time, the thickening of this near-stationary depleted layer progressively forces the termination of melting to higher depths, reducing the melt production rate. Such a process gradually leads both to decreasing efficient melt extraction and increasing mantle lithospheric-melt interactions. The accumulation of this refractory material also causes long-term fluctuations of the volcanic activity, in generating long periods of quiescence. The presence of this residual mantle keel induces over time a lateral flow deflection, which translates into a shift of future melting sites around it. This process gives rise to the horseshoe-like shape of some volcanic islands on slow-moving plates (e.g. Cape Verde, Crozet). Finally, the pronounced topographic swells/bulges observed in this environments may also be supported both by large scale mantle upwelling and their residual mantle roots. Most of these processes are likely similar to those observed on Martian giant shield volcanoes. The goal of this presentation will be to describe the essential characteristics of intra-oceanic plumes on slow moving plates on the Earth and to point out their similarities with those of the large shield volcanoes from the Tharsis region.

Fabrication, testing and modeling of a new flexible armor inspired from natural fish scales and osteoderms.

PubMed

Chintapalli, Ravi Kiran; Mirkhalaf, Mohammad; Dastjerdi, Ahmad Khayer; Barthelat, Francois

2014-09-01

Crocodiles, armadillo, turtles, fish and many other animal species have evolved flexible armored skins in the form of hard scales or osteoderms, which can be described as hard plates of finite size embedded in softer tissues. The individual hard segments provide protection from predators, while the relative motion of these segments provides the flexibility required for efficient locomotion. In this work, we duplicated these broad concepts in a bio-inspired segmented armor. Hexagonal segments of well-defined size and shape were carved within a thin glass plate using laser engraving. The engraved plate was then placed on a soft substrate which simulated soft tissues, and then punctured with a sharp needle mounted on a miniature loading stage. The resistance of our segmented armor was significantly higher when smaller hexagons were used, and our bio-inspired segmented glass displayed an increase in puncture resistance of up to 70% compared to a continuous plate of glass of the same thickness. Detailed structural analyses aided by finite elements revealed that this extraordinary improvement is due to the reduced span of individual segments, which decreases flexural stresses and delays fracture. This effect can however only be achieved if the plates are at least 1000 stiffer than the underlying substrate, which is the case for natural armor systems. Our bio-inspired system also displayed many of the attributes of natural armors: flexible, robust with 'multi-hit' capabilities. This new segmented glass therefore suggests interesting bio-inspired strategies and mechanisms which could be systematically exploited in high-performance flexible armors. This study also provides new insights and a better understanding of the mechanics of natural armors such as scales and osteoderms.

Optimizing piezoelectric receivers for acoustic power transfer applications

NASA Astrophysics Data System (ADS)

Gorostiaga, M.; Wapler, M. C.; Wallrabe, U.

2018-07-01

In this paper, we aim to optimize piezoelectric plate receivers for acoustic power transfer applications by analyzing the influence of the losses and of the acoustic boundary conditions. We derive the analytic expressions of the efficiency of the receiver with the optimal electric loads attached, and analyze the maximum efficiency value and its frequency with different loss and acoustic boundary conditions. To validate the analytical expressions that we have derived, we perform experiments in water with composite transducers of different filling fractions, and see that a lower acoustic impedance mismatch can compensate the influence of large dielectric and acoustic losses to achieve a good performance. Finally, we briefly compare the advantages and drawbacks of composite transducers and pure PZT (lead zirconate titanate) plates as acoustic power receivers, and conclude that 1–3 composites can achieve similar efficiency values in low power applications due to their adjustable acoustic impedance.

Proceedings of the Flat-Plate Solar Array Project Workshop on Crystal Gowth for High-Efficiency Silicon Solar Cells

NASA Technical Reports Server (NTRS)

Dumas, K. A. (Editor)

1985-01-01

A Workshop on Crystal Growth for High-Efficiency Silicon Solar Cells was held December 3 and 4, 1984, in San Diego, California. The Workshop offered a day and a half of technical presentations and discussions and an afternoon session that involved a panel discussion and general discussion of areas of research that are necessary to the development of materials for high-efficiency solar cells. Topics included the theoretical and experimental aspects of growing high-quality silicon crystals, the effects of growth-process-related defects on photovoltaic devices, and the suitability of various growth technologies as cost-effective processes. Fifteen invited papers were presented, with a discussion period following each presentation. The meeting was organized by the Flat-Plate Solar Array Project of the Jet Propulsion Laboratory. These Proceedings are a record of the presentations and discussions, edited for clarity and continuity.

Biocular vehicle display optical designs

NASA Astrophysics Data System (ADS)

Chu, H.; Carter, Tom

2012-06-01

Biocular vehicle display optics is a fast collimating lens (f / # < 0.9) that presents the image of the display at infinity to both eyes of the viewer. Each eye captures the scene independently and the brain merges the two images into one through the overlapping portions of the images. With the recent conversion from analog CRT based displays to lighter, more compact active-matrix organic light-emitting diodes (AMOLED) digital image sources, display optical designs have evolved to take advantage of the higher resolution AMOLED image sources. To maximize the field of view of the display optics and fully resolve the smaller pixels, the digital image source is pre-magnified by relay optics or a coherent taper fiber optics plate. Coherent taper fiber optics plates are used extensively to: 1. Convert plano focal planes to spherical focal planes in order to eliminate Petzval field curvature. This elimination enables faster lens speed and/or larger field of view of eye pieces, display optics. 2. Provide pre-magnification to lighten the work load of the optics to further increase the numerical aperture and/or field of view. 3. Improve light flux collection efficiency and field of view by collecting all the light emitted by the image source and guiding imaging light bundles toward the lens aperture stop. 4. Reduce complexity of the optical design and overall packaging volume by replacing pre-magnification optics with a compact taper fiber optics plate. This paper will review and compare the performance of biocular vehicle display designs without and with taper fiber optics plate.

Development of technique for AR coating and nickel and copper metallization of solar cells: FPS project, product development

NASA Technical Reports Server (NTRS)

Rominger, C. G.

1981-01-01

Silicon nitride and nickel pastes are investigated in conjunction with a brush copper plating process for the purpose of identifying one or more fabrication sequences which yield at least 10 percent efficient N(+)/P(+) flat plate solar cells. The adhesion of all nickel pastes is reduced significantly when subjected to acidic and alkaline brush copper plating solutions as a result of a combination of thermally induced stress and chemical attack of the frit, which occurs at the interface with the silicon solar cell. The AgF is penetrating the 800 a of Si3N4 and ohmic contact is occurring at all fire-in tempertures. During the brush plating process, fingers and buss bars tend to spread.

A user's manual for the Electromagnetic Surface Patch code: ESP version 3

NASA Technical Reports Server (NTRS)

Newman, E. H.; Dilsavor, R. L.

1987-01-01

This report serves as a user's manual for Version III of the Electromagnetic Surface Patch Code or ESP code. ESP is user-oriented, based on the method of moments (MM) for treating geometries consisting of an interconnection of thin wires and perfectly conducting polygonal plates. Wire/plate junctions must be about 0.1 lambda or more from any plate edge. Several plates may intersect along a common edge. Excitation may be by either a delta-gap voltage generator or by a plane wave. The thin wires may have finite conductivity and also may contain lumped loads. The code computes most of the usual quantities of interest such as current distribution, input impedance, radiation efficiency, mutual coupling, far zone gain patterns (both polarizations) and radar-cross-section (both/cross polarizations).

Compact OAM microscope for edge enhancement of biomedical and object samples

NASA Astrophysics Data System (ADS)

Gozali, Richard; Nguyen, Thien-An; Bendau, Ethan; Alfano, Robert R.

2017-09-01

The production of orbital angular momentum (OAM) by using a q-plate, which functions as an electrically tunable spatial frequency filter, provides a simple and efficient method of edge contrast in biological and medical sample imaging for histological evaluation of tissue, smears, and PAP smears. An instrument producing OAM, such as a q-plate, situated at the Fourier plane of a 4f lens system, similar to the use of a high-pass spatial filter, allows the passage of high spatial frequencies and enables the production of an image with highly illuminated edges contrasted against a dark background for both opaque and transparent objects. Compared with ordinary spiral phase plates and spatial light modulators, the q-plate has the added advantage of electric control and tunability.

Excited waves in shear layers

NASA Technical Reports Server (NTRS)

Bechert, D. W.

1982-01-01

The generation of instability waves in free shear layers is investigated. The model assumes an infinitesimally thin shear layer shed from a semi-infinite plate which is exposed to sound excitation. The acoustical shear layer excitation by a source further away from the plate edge in the downstream direction is very weak while upstream from the plate edge the excitation is relatively efficient. A special solution is given for the source at the plate edge. The theory is then extended to two streams on both sides of the shear layer having different velocities and densities. Furthermore, the excitation of a shear layer in a channel is calculated. A reference quantity is found for the magnitude of the excited instability waves. For a comparison with measurements, numerical computations of the velocity field outside the shear layer were carried out.

Efficient cooling of rocky planets by intrusive magmatism

NASA Astrophysics Data System (ADS)

Lourenço, Diogo L.; Rozel, Antoine B.; Gerya, Taras; Tackley, Paul J.

2018-05-01

The Earth is in a plate tectonics regime with high surface heat flow concentrated at constructive plate boundaries. Other terrestrial bodies that lack plate tectonics are thought to lose their internal heat by conduction through their lids and volcanism: hotter planets (Io and Venus) show widespread volcanism whereas colder ones (modern Mars and Mercury) are less volcanically active. However, studies of terrestrial magmatic processes show that less than 20% of melt volcanically erupts, with most melt intruding into the crust. Signatures of large magmatic intrusions are also found on other planets. Yet, the influence of intrusive magmatism on planetary cooling remains unclear. Here we use numerical magmatic-thermo-mechanical models to simulate global mantle convection in a planetary interior. In our simulations, warm intrusive magmatism acts to thin the lithosphere, leading to sustained recycling of overlying crustal material and cooling of the mantle. In contrast, volcanic eruptions lead to a thick lithosphere that insulates the upper mantle and prevents efficient cooling. We find that heat loss due to intrusive magmatism can be particularly efficient compared to volcanic eruptions if the partitioning of heat-producing radioactive elements into the melt phase is weak. We conclude that the mode of magmatism experienced by rocky bodies determines the thermal and compositional evolution of their interior.

Test of VPHGS in SHSG for use at cryogenic temperatures

NASA Astrophysics Data System (ADS)

Insaustia, Maider; Garzón, Francisco; Mas-Abellán, P.; Madrigal, R.; Fimia, A.

2017-05-01

Silver halide sensitized gelatin (SHSG) processes are interesting because they combine the spectral and energetic sensitivity of a photographic emulsions with good optical quality and high diffraction efficiency of dichromate gelatin (DCG). Previous papers had been demonstrated that it is possible to obtain diffraction efficiencies near to 90% with Agfa- Gevaert plates and Colour Holographic plates in SHSG transmission gratings. In this communication, we report on the performances measured at room temperature and in cryogenic conditions of a set of volume phase holographic gratings(VPHGs) manufactured with SHSG process aimed at their use in astronomical instrumentations. Two set of diffraction gratings has been manufactured using different processing. The first with SHSG process and the second with typical bleached process (developed with AAC and bleached in R-10). In both cases the plate was BB640, ultrafine grain emulsions with a nominal thickness of 9 μm. The recording was performed with asymmetric geometry a 30° degrees between the light beams of wavelength 632.8 nm (He-Ne laser), which give a raise a spectral frequency of 800 l/m. The exposure was between 46 to 2048 μJ/cm2. The results give us information about Bragg plane modification and reduction of diffraction efficiency when we introduced the VPHG to 77° K. In the case of SHSG process the final diffraction efficiency after cryogenic temperature are better at some exposure energy than previous measurements at room temperature. This experimental result give us possibilities to applied SHSG process in Astrophysics applications.

Enrichment of undifferentiated type a spermatogonia from goat testis using discontinuous percoll density gradient and differential plating.

PubMed

Heidari, Banafsheh; Gifani, Minoo; Shirazi, Abolfazl; Zarnani, Amir-Hassan; Baradaran, Behzad; Naderi, Mohammad Mehdi; Behzadi, Bahareh; Borjian-Boroujeni, Sara; Sarvari, Ali; Lakpour, Niknam; Akhondi, Mohammad Mehdi

2014-04-01

The well documented source for adult multipotent stem cells is Spermatogonial Stem Cells (SSCs). They are the foundation of spermatogenesis in the testis throughout adult life by balancing self-renewal and differentiation. The aim of this study was to assess the effect of percoll density gradient and differential plating on enrichment of undifferentiated type A spermatogonia in dissociated cellular suspension of goat testes. Additionally, we evaluated the separated fractions of the gradients in percoll and samples in differential plating at different times for cell number, viability and purification rate of goat SSCs in culture. Testicular cells were successfully isolated from one month old goat testis using two-step enzymatic digestion and followed by two purification protocols, differential plating with different times of culture (3, 4, 5, and 6 hr) and discontinuous percoll density with different gradients (20, 28, 30, and 32%). The difference of percentage of undifferentiated SSCs (PGP9.5 positive) in each method was compared using ANOVA and comparison between the highest percentage of corresponding value between two methods was carried out by t-test using Sigma Stat (ver. 3.5). The highest PGP9.5 (94.6±0.4) and the lowest c-Kit positive (25.1±0.7) in Percoll method was significantly (p ≤ 0.001) achieved in 32% percoll gradient. While the corresponding rates in differential plating method for the highest PGP9.5 positive cells (81.3±1.1) and lowest c-Kit (17.1±1.4) was achieved after 5 hr culturing (p < 0.001). The enrichment of undifferentiated type A spermatogonia using Percoll was more efficient than differential plating method (p < 0.001). Percoll density gradient and differential plating were efficient and fast methods for enrichment of type A spermatogonial stem cells from goat testes.

Enrichment of Undifferentiated Type A Spermatogonia from Goat Testis Using Discontinuous Percoll Density Gradient and Differential Plating

PubMed Central

Heidari, Banafsheh; Gifani, Minoo; Shirazi, Abolfazl; Zarnani, Amir-Hassan; Baradaran, Behzad; Naderi, Mohammad Mehdi; Behzadi, Bahareh; Borjian-Boroujeni, Sara; Sarvari, Ali; Lakpour, Niknam; Akhondi, Mohammad Mehdi

2014-01-01

Background The well documented source for adult multipotent stem cells is Spermatogonial Stem Cells (SSCs). They are the foundation of spermatogenesis in the testis throughout adult life by balancing self-renewal and differentiation. The aim of this study was to assess the effect of percoll density gradient and differential plating on enrichment of undifferentiated type A spermatogonia in dissociated cellular suspension of goat testes. Additionally, we evaluated the separated fractions of the gradients in percoll and samples in differential plating at different times for cell number, viability and purification rate of goat SSCs in culture. Methods Testicular cells were successfully isolated from one month old goat testis using two-step enzymatic digestion and followed by two purification protocols, differential plating with different times of culture (3, 4, 5, and 6 hr) and discontinuous percoll density with different gradients (20, 28, 30, and 32%). The difference of percentage of undifferentiated SSCs (PGP9.5 positive) in each method was compared using ANOVA and comparison between the highest percentage of corresponding value between two methods was carried out by t-test using Sigma Stat (ver. 3.5). Results The highest PGP9.5 (94.6±0.4) and the lowest c-Kit positive (25.1±0.7) in Percoll method was significantly (p ≤ 0.001) achieved in 32% percoll gradient. While the corresponding rates in differential plating method for the highest PGP9.5 positive cells (81.3±1.1) and lowest c-Kit (17.1±1.4) was achieved after 5 hr culturing (p < 0.001). The enrichment of undifferentiated type A spermatogonia using Percoll was more efficient than differential plating method (p < 0.001). Conclusion Percoll density gradient and differential plating were efficient and fast methods for enrichment of type A spermatogonial stem cells from goat testes. PMID:24834311

Standard performance tests of collectors of solar thermal energy: A selectively coated, flat-plate copper collector with one transparent cover and a tube-to-tube spacing of 3-7/8 inches

NASA Technical Reports Server (NTRS)

1976-01-01

Basic test results are given of a flat-plate solar collector whose performance was determined in the NASA-Lewis solar simulator. The collector was tested over ranges of inlet temperatures, fluxes, and coolant flow rates. Collector efficiency is correlated in terms of inlet temperature and flux level.

Analysis of a rectangular ceramic plate in electrically forced thickness-twist vibration as a piezoelectric transformer.

PubMed

Yang, Jiashi; Liu, Jinjin; Li, Jiangyu

2007-04-01

A rectangular ceramic plate with appropriate electrical load and operating mode is analyzed for piezoelectric transformer application. An exact solution from the three-dimensional equations of linear piezoelectricity is obtained. The solution simulates the real operating situation of a transformer as a vibrating piezoelectric body connected to a circuit. Transforming ratio, input admittance, and efficiency of the transformer are obtained.

Development of an innovative solar absorber

NASA Astrophysics Data System (ADS)

Goodchild, Gavin

Solar thermal systems have great potential to replace or reduce the dependence of conventional fossil fuel based heating technologies required for space and water heating. Specifically solar domestic hot water systems can contribute 50-75% of the annual thermal load. To date residential users have been slow to purchase and install systems, primarily due to the large monetary investment required to purchase and install a system. Recent innovations in materials design and manufacturing techniques, offer opportunities for the development of absorber plate designs that have the potential to reduce cost, increase efficiency and reduce payback periods. Consequently, this design study was conducted in conjunction with industrial partners to develop an improved absorber based on roll bond manufacturing that can be produced at reduced cost with comparable or greater thermal efficiency.

Multi-Stage Metering Mechanism for Transplanting of Vegetable Seedlings in Paper Pots

NASA Astrophysics Data System (ADS)

Nandede, B. M.; Raheman, H.

2015-12-01

A multi-stage rotating cup type metering mechanism was developed for transplanting of vegetable seedlings of tomato, brinjal and chili raised in paper pots. The developed setup consisted of a seedling feeding wheel, metering wheel, fixed slotted plate, seedling delivery tube, furrow opener, furrow closer and a power transmission system. Its evaluation was carried out with pot seedlings of tomato, brinjal and chili of 8-11 cm height at five forward speeds (0.6, 0.9, 1.2, 2.2 and 3.2 km/h) and two plant spacings (45 and 60 cm) in controlled soil bin condition. The mean values of feeding efficiency, conveying efficiency, planting efficiency and overall efficiency of the multistage metering unit were observed to be higher than 90 % for forward speeds of 0.6 to 2.2 km/h. With further increase in speed to 3.2 km/h, the feeding and conveying efficiency were observed to be higher than 90 %, whereas, the planting efficiency drastically reduced to around 50 % due to the problem in getting the pot seedlings vertically in the furrow. Also the seedlings were falling into the furrow at an angle greater than 70° to the vertical, hence not suitable for transplanting.

Architectural Blueprint for Plate Boundary Observatories based on interoperable Data Management Platforms

NASA Astrophysics Data System (ADS)

Kerschke, D. I.; Häner, R.; Schurr, B.; Oncken, O.; Wächter, J.

2014-12-01

Interoperable data management platforms play an increasing role in the advancement of knowledge and technology in many scientific disciplines. Through high quality services they support the establishment of efficient and innovative research environments. Well-designed research environments can facilitate the sustainable utilization, exchange, and re-use of scientific data and functionality by using standardized community models. Together with innovative 3D/4D visualization, these concepts provide added value in improving scientific knowledge-gain, even across the boundaries of disciplines. A project benefiting from the added value is the Integrated Plate boundary Observatory in Chile (IPOC). IPOC is a European-South American network to study earthquakes and deformation at the Chilean continental margin and to monitor the plate boundary system for capturing an anticipated great earthquake in a seismic gap. In contrast to conventional observatories that monitor individual signals only, IPOC captures a large range of different processes through various observation methods (e.g., seismographs, GPS, magneto-telluric sensors, creep-meter, accelerometer, InSAR). For IPOC a conceptual design has been devised that comprises an architectural blueprint for a data management platform based on common and standardized data models, protocols, and encodings as well as on an exclusive use of Free and Open Source Software (FOSS) including visualization components. Following the principles of event-driven service-oriented architectures, the design enables novel processes by sharing and re-using functionality and information on the basis of innovative data mining and data fusion technologies. This platform can help to improve the understanding of the physical processes underlying plate deformations as well as the natural hazards induced by them. Through the use of standards, this blueprint can not only be facilitated for other plate observing systems (e.g., the European Plate Observing System EPOS), it also supports integrated approaches to include sensor networks that provide complementary processes for dynamic monitoring. Moreover, the integration of such observatories into superordinate research infrastructures (federation of virtual observatories) will be enabled.

Tectonic controls on earthquake size distribution and seismicity rate: slab buoyancy and slab bending

NASA Astrophysics Data System (ADS)

Nishikawa, T.; Ide, S.

2014-12-01

There are clear variations in maximum earthquake magnitude among Earth's subduction zones. These variations have been studied extensively and attributed to differences in tectonic properties in subduction zones, such as relative plate velocity and subducting plate age [Ruff and Kanamori, 1980]. In addition to maximum earthquake magnitude, the seismicity of medium to large earthquakes also differs among subduction zones, such as the b-value (i.e., the slope of the earthquake size distribution) and the frequency of seismic events. However, the casual relationship between the seismicity of medium to large earthquakes and subduction zone tectonics has been unclear. Here we divide Earth's subduction zones into over 100 study regions following Ide [2013] and estimate b-values and the background seismicity rate—the frequency of seismic events excluding aftershocks—for subduction zones worldwide using the maximum likelihood method [Utsu, 1965; Aki, 1965] and the epidemic type aftershock sequence (ETAS) model [Ogata, 1988]. We demonstrate that the b-value varies as a function of subducting plate age and trench depth, and that the background seismicity rate is related to the degree of slab bending at the trench. Large earthquakes tend to occur relatively frequently (lower b-values) in shallower subduction zones with younger slabs, and more earthquakes occur in subduction zones with deeper trench and steeper dip angle. These results suggest that slab buoyancy, which depends on subducting plate age, controls the earthquake size distribution, and that intra-slab faults due to slab bending, which increase with the steepness of the slab dip angle, have influence on the frequency of seismic events, because they produce heterogeneity in plate coupling and efficiently inject fluid to elevate pore fluid pressure on the plate interface. This study reveals tectonic factors that control earthquake size distribution and seismicity rate, and these relationships between seismicity and tectonic properties may be useful for seismic risk assessment.

X-ray evaluation of SEM technique for determining the crystallography of echinoid skeletons.

PubMed

Dillaman, R M; Hart, H V

1981-01-01

Coronal plates of the sea urchin Strongylocentrotus purpuratus have a microstructure typified by smooth textured trabeculae. When plates were decorated with calcite crystals each rhombohedron had the same orientation regardless of its location on the plate. When the sample was oriented so that the three edges of the rhombohedron formed equal 120 degrees angles and the three crystal faces appeared to form equal angles with the plane of the photograph, the c-axis of the plate paralleled the electron beam and the three a-axes were 30 degrees counterclockwise from the edges. These a-axes were then related to a plate edge recorded in a low magnification micrograph. Directions of the a-axes of each plate were also measured using a back-reflection Laue x-ray diffraction camera. A comparison of a-axes measured by the two techniques showed an average difference of 3 degrees, indicating that decorated crystal grew in crystallographic continuity with the plate. Assuming this relationship remains constant, the decoration technique appears to be an accurate and efficient method for evaluating the crystallography of echinoid skeletal units. Analysis of a polar plot of a-axes for 11 plates indicated that the a-axes were not randomly oriented; however, definitive relationships must await more extensive investigations.

Comparison of methods for isolation and enumeration of thermophilic actinomycetes from dust.

PubMed Central

Treuhaft, M W; Arden Jones, M P

1982-01-01

Thermophilic actinomycetes are the primary sensitizing agents in farmer's lung disease. We compared dilution pour-plate and spread-plate methods for their usefulness in enumerating thermophilic actinomycetes in moldy silage dust and evaluated the ability of a nonquantitative gravity settling technique to recover thermophilic actinomycetes from moldy silage. Spread plates and pour plates yielded similar estimates of total thermophiles. Higher counts were observed on spread plates (P less than 0.05) for Thermoactinomyces candidus, Micropolyspora faeni, and Saccharomonospora viridis. M. faeni and S. viridis were less efficient than T. candidus in breaking through the agar of pour plates to form colonies which could be identified. Coefficients of variability were less than 10% for the two methods. The relative proportion of organisms recovered by the settling method correlated well with that recovered on spread plates for M. faeni (r = 0.79), S. viridis (r = 0.88), and Thermomonospora spp. (r = 0.79), but not well for T. candidus (r = 0.28). When sophisticated air-sampling equipment is not available, dilution spread plates of dust washings provide a reproducible method for enumerating a broad range of thermophilic actinomycetes of interest. The gravity settling method is a simple, rapid alternative when isolation is all that is required. PMID:6761363

Performance enhancement of an air-coupled multiple moving membrane capacitive micromachined ultrasonic transducer using an optimized middle plate configuration

NASA Astrophysics Data System (ADS)

Emadi, Arezoo; Buchanan, Douglas

2016-10-01

A multiple moving membrane capacitive micromachined ultrasonic transducer has been developed. This transducer cell structure includes a second flexible plate suspended between the transducer top plate and the fixed bottom electrode. The added plate influences the transducer top plate deflection map and, therefore, the transducer properties. Three series of individual air-coupled, dual deflectable plate transducers and two 1×27 element transducer arrays were fabricated using multiuser microelectromechanical systems (MEMS) processes (MUMPs). Each set of transducers included devices with middle plate radii from 22% to 65% of the corresponding transducer top plate radius. The effect of the transducer middle plate configuration has been investigated. Electrical, optical, and acoustic characterizations were conducted and the results were compared with the simulation findings. It was found that the transducer top plate amplitude of vibration is significantly enhanced with a wider middle deflectable plate. The electrical and optical measurement results are shown to be in good agreement with simulation results. The acoustic measurement results indicated a 37% increase in the amplitude of transmitted signal by the 1-MHz air-couple transducer when its middle plate radius was increased by 35%.

Image plates as x-ray detectors in plasma physics experiments

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

Gales, S.G.; Bentley, C.D.

2004-10-01

The performance of image plates based on the photostimulable phosphor BaF(Br,l):Eu{sup 2+} has been investigated and compared with x-ray film. Evaluation of detective quantum efficiency (DQE), sensitivity, dynamic range, and linearity was carried out for several types of commercially available image plate, using the Excalibur soft x-ray calibration facility at AWE. Image plate response was found to be linear over a dynamic range of 5 orders of magnitude. One type of image plate was found to have a number of advantages for soft x-ray detection, with a measured sensitivity 1 order of magnitude greater than that of Kodak Industrex CXmore » and DEF-5 x-ray film. The DQE of this plate was found to be superior to that of film at low [less than 10{sup 3} photons/(50 {mu}m){sup 2}] and high fluxes [greater than 10{sup 4} photons/(50 {mu}m){sup 2}]. The spatial resolution of image plates, scanned with several models of commercial image plate readers, has been evaluated using a USAF resolution test target. The highest spatial resolution measured is 35 {mu}m. Though this is significantly lower than the resolution possible with film, it is sufficient for many applications. Image plates were fielded in a refractive x-ray lens imaging diagnostic on the 1 TW Helen laser and these results are discussed.« less

Characterization of Pulse Reverses Electroforming on Hard Gold Coating.

PubMed

Byoun, Young-Min; Noh, Young-Tai; Kim, Young-Geun; Ma, Seung-Hwan; Kim, Gwan-Hoon

2018-03-01

Effect of pulse reverse current (PRC) method on brass coatings electroplated from gold solution was investigated by various plating parameters such as plating duration, the anodic duty cycle, the anodic current density and the cathodic current density. The reversed current results in a significant change in the morphology of electrodeposits, improvement of the overall current efficiency and reduction of deposit porosity. With longer pulses, hemispherical surface features are generated, while larger grains result from shorter pulse widths. The porosity of the plated samples is found to decrease compared with results at the same time-average plating rate obtained from DC or Pulse plating. A major impediment to reducing gold later thickness is the corrosion of the underlying substrate, which is affected by the porosity of the gold layer. Both the morphology and the hydrogen evolution reaction have significant impact on porosity. PRC plating affect hydrogen gold and may oxidize hydrogen produced during the cathodic portion of the waveform. Whether the dissolution of gold and oxidation of hydrogen occur depends on the type of plating bath and the plating conditions adapted. In reversed pulse plating, the amount of excess near-surface cyanide is changed after the cathodic current is applied, and the oxidation of gold under these conditions has not been fully addressed. The effects of the current density, pulse-reverse ratio and brightener concentration of the electroplating process were investigated and optimized for suitable performance.

Thermal performance evaluation of Solar Energy Products Company (SEPCO) 'Soloron' collector tested outdoors

NASA Technical Reports Server (NTRS)

Chiou, J., Sr.

1977-01-01

The test article, Model EF-212, Serial Nr. 002, is a single glazed collector with a nonselective absorber plate, using flowing air as the heat transfer medium. The absorber plate and box frame are aluminum and the insulation is one inch isocyanurate foam board with thermal conductivity of 0.11 (BTU/sq ft Hr0/ft.) The tests included the following. (1) time constant test, (2) collector efficiency test, (3) collector stagnation test, (4) incident angle modifier test, (5) load test, (6) weathering test, and (7) absorber plate optical properties test. The results of these tests are tabulated, graphed, or otherwise recorded.

Stochastic Investigation of Natural Frequency for Functionally Graded Plates

NASA Astrophysics Data System (ADS)

Karsh, P. K.; Mukhopadhyay, T.; Dey, S.

2018-03-01

This paper presents the stochastic natural frequency analysis of functionally graded plates by applying artificial neural network (ANN) approach. Latin hypercube sampling is utilised to train the ANN model. The proposed algorithm for stochastic natural frequency analysis of FGM plates is validated and verified with original finite element method and Monte Carlo simulation (MCS). The combined stochastic variation of input parameters such as, elastic modulus, shear modulus, Poisson ratio, and mass density are considered. Power law is applied to distribute the material properties across the thickness. The present ANN model reduces the sample size and computationally found efficient as compared to conventional Monte Carlo simulation.

Experimental study on flat plate air solar collector using a thin sand layer

NASA Astrophysics Data System (ADS)

Lati, Moukhtar; Boughali, Slimane; Bouguettaia, Hamza; Mennouche, Djamel; Bechki, Djamel

2016-07-01

A flat plate air solar collector was constructed in the laboratory of New and Renewable Energy in Arid Zones LENREZA, Ouargla University-South East Algeria. The absorber of the flat plate air solar collector was laminated with a thin layer of local sand. This acted as a thermal storage system (packed bed) with a collecting area of 2.15 m2 (0.86 m × 2.5 m). It was noticed that the solar heater integrated with the thermal storage material delivered comparatively higher temperatures; thus, giving a better efficiency than the air heater without the thermal storage system.

[Research on electron density in DC needle-plate corona discharge at atmospheric pressure].

PubMed

Liu, Zhi-Qiang; Guo, Wei; Liu, Tao-Tao; Wu, Wen-Shuo; Liu, Shu-Min

2013-11-01

Using needle-plate discharge device, corona discharge experiment was done in the atmosphere. Through photo of spot size of light-emitting area, the relationship between the voltage and thickness of corona layer was discussed. When the distance between tip and plate is fixed, the thickness of corona layer increases with the increase in voltage; when the voltage is fixed, the thickness of corona layer decreases with the increase in the distance between tip and plate. As spectral intensity of N2 (C3pi(u)) (337.1 nm)reflects high energy electron density, it was measured with emission spectrometry. The results show that high energy electron density is the biggest near the needle tip and the relationship between high energy electron density and voltage is basically linear increasing. Fixing voltage, high energy electron density decreases with the increase in the distance between tip and plate. When the voltage and the distance between tip and plate are fixed, the high energy electron density increases with the decrease in the curvature radius of needle tip. These results are of great importance for the study of plasma parameters of corona discharge.

Transverse electromagnetic horn antenna with resistively-loaded exterior surfaces

DOEpatents

Aurand, John F.

1999-01-01

An improved transverse electromagnetic (TEM) horn antenna comprises a resistive loading material on the exterior surfaces of the antenna plates. The resistive loading material attenuates or inhibits currents on the exterior surfaces of the TEM horn antenna. The exterior electromagnetic fields are of opposite polarity in comparison to the primary and desired interior electromagnetic field, thus inherently cause partial cancellation of the interior wave upon radiation or upon reception. Reducing the exterior fields increases the radiation efficiency of the antenna by reducing the cancellation of the primary interior field (supported by the interior surface currents). This increases the transmit gain and receive sensitivity of the TEM horn antenna, as well as improving the transient (time-domain) response.

Electricity generation in low cost microbial fuel cell made up of earthenware of different thickness.

PubMed

Behera, M; Ghangrekar, M M

2011-01-01

Performance of four microbial fuel cells (MFC-1, MFC-2, MFC-3 and MFC-4) made up of earthen pots with wall thicknesses of 3, 5, 7 and 8.5 mm, respectively, was evaluated. The MFCs were operated in fed batch mode with synthetic wastewater having sucrose as the carbon source. The power generation decreased with increase in the thickness of the earthen pot which was used to make the anode chamber. MFC-1 generated highest sustainable power density of 24.32 mW/m(2) and volumetric power of 1.04 W/m(3) (1.91 mA, 0.191 V) at 100 Ω external resistance. The maximum Coulombic efficiencies obtained in MFC-1, MFC-2, MFC-3 and MFC-4 were 7.7, 7.1, 6.8 and 6.1%, respectively. The oxygen mass transfer and oxygen diffusion coefficients measured for earthen plate of 3 mm thickness were 1.79 × 10(-5) and 5.38 × 10(-6) cm(2)/s, respectively, which implies that earthen plate is permeable to oxygen as other polymeric membranes. The internal resistance increased with increase in thickness of the earthen pot MFCs. The thickness of the earthen material affected the overall performance of MFCs.

Calibration and use of filter test facility orifice plates

NASA Astrophysics Data System (ADS)

Fain, D. E.; Selby, T. W.

1984-07-01

There are three official DOE filter test facilities. These test facilities are used by the DOE, and others, to test nuclear grade HEPA filters to provide Quality Assurance that the filters meet the required specifications. The filters are tested for both filter efficiency and pressure drop. In the test equipment, standard orifice plates are used to set the specified flow rates for the tests. There has existed a need to calibrate the orifice plates from the three facilities with a common calibration source to assure that the facilities have comparable tests. A project has been undertaken to calibrate these orifice plates. In addition to reporting the results of the calibrations of the orifice plates, the means for using the calibration results will be discussed. A comparison of the orifice discharge coefficients for the orifice plates used at the seven facilities will be given. The pros and cons for the use of mass flow or volume flow rates for testing will be discussed. It is recommended that volume flow rates be used as a more practical and comparable means of testing filters. The rationale for this recommendation will be discussed.

A simple and convenient microtiter plate assay for the detection of bactericidal antibodies to Vibrio cholerae O1 and Vibrio cholerae O139.

PubMed

Boutonnier, Alain; Dassy, Bruno; Duménil, Rémy; Guénolé, Alain; Ratsitorahina, Maherisoa; Migliani, René; Fournier, Jean-Michel

2003-12-01

It is believed that the correlate of protection for cholera can be determined by the serum vibriocidal assay. The currently available vibriocidal assays, based on the conventional agar plating technique, are labor intensive. We developed a simple and convenient microtiter plate assay for the detection of vibriocidal antibodies that is equally as efficient for Vibrio cholerae O1 and for V. cholerae O139. The addition of succinate and neotetrazolium made it possible to measure the growth of surviving bacterial target cells by monitoring a color change. We evaluated assay parameters (target strains, growth of target cells, complement source and concentration) that may affect the reproducibility of the method for V. cholerae O139. The results obtained with the microtiter plate assay were uniformly similar to those obtained with the conventional agar plating assay, when testing both the Inaba and Ogawa serotypes of V. cholerae O1. The microtiter plate assay was also convenient for measuring the activity of animal sera and mouse monoclonal antibodies.

Multimodal vibration damping of a plate by piezoelectric coupling to its analogous electrical network

NASA Astrophysics Data System (ADS)

Lossouarn, B.; Deü, J.-F.; Aucejo, M.; Cunefare, K. A.

2016-11-01

Multimodal damping can be achieved by coupling a mechanical structure to an electrical network exhibiting similar modal properties. Focusing on a plate, a new topology for such an electrical analogue is found from a finite difference approximation of the Kirchhoff-Love theory and the use of the direct electromechanical analogy. Discrete models based on element dynamic stiffness matrices are proposed to simulate square plate unit cells coupled to their electrical analogues through two-dimensional piezoelectric transducers. A setup made of a clamped plate covered with an array of piezoelectric patches is built in order to validate the control strategy and the numerical models. The analogous electrical network is implemented with passive components as inductors, transformers and the inherent capacitance of the piezoelectric patches. The effect of the piezoelectric coupling on the dynamics of the clamped plate is significant as it creates the equivalent of a multimodal tuned mass damping. An adequate tuning of the network then yields a broadband vibration reduction. In the end, the use of an analogous electrical network appears as an efficient solution for the multimodal control of a plate.

Standing wave acoustic levitation on an annular plate

NASA Astrophysics Data System (ADS)

Kandemir, Mehmet Hakan; Çalışkan, Mehmet

2016-11-01

In standing wave acoustic levitation technique, a standing wave is formed between a source and a reflector. Particles can be attracted towards pressure nodes in standing waves owing to a spring action through which particles can be suspended in air. This operation can be performed on continuous structures as well as in several numbers of axes. In this study an annular acoustic levitation arrangement is introduced. Design features of the arrangement are discussed in detail. Bending modes of the annular plate, known as the most efficient sound generation mechanism in such structures, are focused on. Several types of bending modes of the plate are simulated and evaluated by computer simulations. Waveguides are designed to amplify waves coming from sources of excitation, that are, transducers. With the right positioning of the reflector plate, standing waves are formed in the space between the annular vibrating plate and the reflector plate. Radiation forces are also predicted. It is demonstrated that small particles can be suspended in air at pressure nodes of the standing wave corresponding to a particular bending mode.

Dilemma in pediatric mandible fractures: resorbable or metallic plates?

PubMed

Taylan Filinte, Gaye; Akan, İsmail Mithat; Ayçiçek Çardak, Gülçin Nujen; Özkaya Mutlu, Özay; Aköz, Tayfun

2015-12-01

The aim of this study was to compare the efficiency of resorbable and metallic plates in open reduction and internal fixation of mandible fractures in children. Thirty-one patients (mean age, 8.05 years; range 20 months-14 years) were operated on various fractures of the mandible (26 [60.4%] symphysis- parasymphysis, 12 [27.9%] condylar-subcondylar fractures, 5 [11.6%] angulus and ramus fractures). Twelve patients were treated with resorbable plates and 19 patients with metallic plates. Mean follow-up time was 41 months (11-74 months) in the metallic hardware group and was 22 months (8-35 months) in the resorbable plate group. Both groups were investigated for primary bone healing, complications, number of operations, and mandibular growth. The results were discussed below. Both groups demonstrated primary bone healing. Minor complications were similar in both groups. The metallic group involved secondary operations for plate removal. Mandibular growth was satisfactory in both groups. Resorbable plates cost more than the metallic ones; however, when the secondary operations are included in the total cost, resorbable plates were favourable. As mandibular growth and complication parameters are similar in both groups, resorbable plates are favored due to avoidance of potential odontogenic injury, elimination of long-term foreign body retention and provision of adequate stability for rapid bone healing. However, learning curve and concerns for decreased stability against heavy forces of mastication accompanied with the resorbable plates when compared to the metallic ones should be kept in mind.

Mitigation of cross-beam energy transfer: Implication of two-state focal zooming on OMEGA

NASA Astrophysics Data System (ADS)

Froula, D. H.; Kessler, T. J.; Igumenshchev, I. V.; Betti, R.; Goncharov, V. N.; Huang, H.; Hu, S. X.; Hill, E.; Kelly, J. H.; Meyerhofer, D. D.; Shvydky, A.; Zuegel, J. D.

2013-08-01

Cross-beam energy transfer (CBET) during OMEGA low-adiabat cryogenic experiments reduces the hydrodynamic efficiency by ˜35%, which lowers the calculated one-dimensional (1-D) yield by a factor of 7. CBET can be mitigated by reducing the diameter of the laser beams relative to the target diameter. Reducing the diameter of the laser beams by 30%, after a sufficient conduction zone has been generated (two-state zooming), is predicted to maintain low-mode uniformity while recovering 90% of the kinetic energy lost to CBET. A radially varying phase plate is proposed to implement two-state zooming on OMEGA. A beam propagating through the central half-diameter of the phase plate will produce a large spot, while a beam propagating through the outer annular region of the phase plate will produce a narrower spot. To generate the required two-state near-field laser-beam profile, a picket driver with smoothing by spectral dispersion (SSD) would pass through an apodizer, forming a beam of half the standard diameter. A second main-pulse driver would co-propagate without SSD through its own apodizer, forming a full-diameter annular beam. Hydrodynamic simulations, using the designed laser spots produced by the proposed zooming scheme on OMEGA, show that implementing zooming will increase the implosion velocity by 25% resulting in a 4.5× increase in the 1-D neutron yield. Demonstrating zooming on OMEGA would validate a viable direct-drive CBET mitigation scheme and help establish a pathway to hydrodynamically equivalent direct-drive-ignition implosions by increasing the ablation pressure (1.6×), which will allow for more stable implosions at ignition-relevant velocities.

Improving the ablation efficiency of excimer laser systems with higher repetition rates through enhanced debris removal and optimized spot pattern.

PubMed

Arba-Mosquera, Samuel; Klinner, Thomas

2014-03-01

To evaluate the reasons for the required increased radiant exposure for higher-repetition-rate excimer lasers and determine experimentally possible compensations to achieve equivalent ablation profiles maintaining the same single-pulse energies and radiant exposures for laser repetition rates ranging from 430 to 1000 Hz. Schwind eye-tech-solutions GmbH and Co. KG, Kleinostheim, Germany. Experimental study. Poly(methyl methacrylate) (PMMA) plates were photoablated. The pulse laser energy was maintained during all experiments; the effects of the flow of the debris removal, the shot pattern for the correction, and precooling the PMMA plates were evaluated in terms of achieved ablation versus repetition rate. The mean ablation performance ranged from 88% to 100%; the variability between the profile measurements ranged from 1.4% to 6.2%. Increasing the laser repetition rate from 430 Hz to 1000 Hz reduced the mean ablation performance from 98% to 91% and worsened the variability from 1.9% to 4.3%. Increasing the flow of the debris removal, precooling the PMMA plates to -18°C, and adapting the shot pattern for the thermal response of PMMA to excimer ablation helped stabilize the variability. Only adapting the shot pattern for the thermal response of PMMA to excimer ablation helped stabilize the mean ablation performance. The ablation performance of higher-repetition-rate excimer lasers on PMMA improved with improvements in the debris removal systems and shot pattern. More powerful debris removal systems and smart shot patterns in terms of thermal response improved the performance of these excimer lasers. Copyright © 2014 ASCRS and ESCRS. Published by Elsevier Inc. All rights reserved.

Differential specificity of selective culture media for enumeration of pathogenic vibrios: advantages and limitations of multi-plating methods.

PubMed

Nigro, Olivia D; Steward, Grieg F

2015-04-01

Plating environmental samples on vibrio-selective chromogenic media is a commonly used technique that allows one to quickly estimate concentrations of putative vibrio pathogens or to isolate them for further study. Although this approach is convenient, its usefulness depends directly on how well the procedure selects against false positives. We tested whether a chromogenic medium, CHROMagar Vibrio (CaV), used alone (single-plating) or in combination (double-plating) with a traditional medium thiosulfate-citrate-bile-salts (TCBS), could improve the discrimination among three pathogenic vibrio species (Vibrio cholerae, Vibrio parahaemolyticus, and Vibrio vulnificus) and thereby decrease the number of false-positive colonies that must be screened by molecular methods. Assays were conducted on water samples from two estuarine environments (one subtropical, one tropical) in a variety of seasonal conditions. The results of the double-plating method were confirmed by PCR and 16S rRNA sequencing. Our data indicate that there is no significant difference in the false-positive rate between CaV and TCBS when using a single-plating technique, but determining color changes on the two media sequentially (double-plating) reduced the rate of false positive identification in most cases. The improvement achieved was about two-fold on average, but varied greatly (from 0- to 5-fold) and depended on the sampling time and location. The double-plating method was most effective for V. vulnificus in warm months, when overall V. vulnificus abundance is high (false positive rates as low as 2%, n=178). Similar results were obtained for V. cholerae (minimum false positive rate of 16%, n=146). In contrast, the false positive rate for V. parahaemolyticus was always high (minimum of 59%, n=109). Sequence analysis of false-positive isolates indicated that the majority of confounding isolates are from the Vibrionaceae family, however, members of distantly related bacterial groups were also able to grow on vibrio-selective media, even when using the double-plating method. In conclusion, the double-plating assay is a simple means to increase the efficiency of identifying pathogenic vibrios in aquatic environments and to reduce the number of molecular assays required for identity confirmation. However, the high spatial and temporal variability in the performance of the media mean that molecular approaches are still essential to obtain the most accurate vibrio abundance estimates from environmental samples. Copyright © 2015 Elsevier B.V. All rights reserved.

A new concept of hybrid photovoltaic thermal (PVT) collector with natural circulation

NASA Astrophysics Data System (ADS)

Lu, Longsheng; Wang, Xiaowu; Wang, Shuai; Liu, Xiaokang

2017-07-01

Hybrid photovoltaic thermal (PVT) technology refers to the integration of a photovoltaic module into a conventional solar thermal collector. Generally, the traditional design of a PVT collector has solar cells fixed on the top surface of an absorber in a flat-plate solar thermal collector. In this work, we presented a new concept of water-based PVT collector in which solar cells were directly placed on the bottom surface of its glass cover. A dynamic numerical model of this new PVT is developed and validated by experimental tests. With numerical analysis, it is found that at same covering factor, the electricity conversion efficiency of solar cells of the new PVT exceed that of the traditional PVT by nearly 10% while its thermal efficiency is approximately 30% lower than that of the traditional PVT. When the covering factor changes from 0.05 to 1, the thermal efficiency of the new PVT drops nearly 70%. The thermal efficiency of both the new PVT and the traditional PVT rise up as the water mass in tank increases. Meanwhile, the final water temperature in tank of the traditional PVT collector declines more than 17 °C, whereas that of the new PVT declines less than 6 °C, when the water mass increases from 100 to 300 kg.

Hindlimb heating increases vascular access of large molecules to murine tibial growth plates measured by in vivo multiphoton imaging

PubMed Central

Efaw, Morgan L.; Williams, Rebecca M.

2013-01-01

Advances in understanding the molecular regulation of longitudinal growth have led to development of novel drug therapies for growth plate disorders. Despite progress, a major unmet challenge is delivering therapeutic agents to avascular-cartilage plates. Dense extracellular matrix and lack of penetrating blood vessels create a semipermeable “barrier,” which hinders molecular transport at the vascular-cartilage interface. To overcome this obstacle, we used a hindlimb heating model to manipulate bone circulation in 5-wk-old female mice (n = 22). Temperatures represented a physiological range of normal human knee joints. We used in vivo multiphoton microscopy to quantify temperature-enhanced delivery of large molecules into tibial growth plates. We tested the hypothesis that increasing hindlimb temperature from 22°C to 34°C increases vascular access of large systemic molecules, modeled using 10, 40, and 70 kDa dextrans that approximate sizes of physiological regulators. Vascular access was quantified by vessel diameter, velocity, and dextran leakage from subperichondrial plexus vessels and accumulation in growth plate cartilage. Growth plate entry of 10 kDa dextrans increased >150% at 34°C. Entry of 40 and 70 kDa dextrans increased <50%, suggesting a size-dependent temperature enhancement. Total dextran levels in the plexus increased at 34°C, but relative leakage out of vessels was not temperature dependent. Blood velocity and vessel diameter increased 118% and 31%, respectively, at 34°C. These results demonstrate that heat enhances vascular carrying capacity and bioavailability of large molecules around growth plates, suggesting that temperature could be a noninvasive strategy for modulating delivery of therapeutics to impaired growth plates of children. PMID:24371019

Trench-parallel spreading ridge subduction and its consequences for the geological evolution of the overriding plate: Insights from analogue models and comparison with the Neogene subduction beneath Patagonia

NASA Astrophysics Data System (ADS)

Salze, Méline; Martinod, Joseph; Guillaume, Benjamin; Kermarrec, Jean-Jacques; Ghiglione, Matias C.; Sue, Christian

2018-07-01

A series of 3-D asthenospheric-scale analogue models have been conducted in the laboratory in order to simulate the arrival of a spreading ridge at the trench and understand its effect on plate kinematics, slab geometry, and on the deformation of the overriding plate. These models are made of a two-layered linearly viscous system simulating the lithosphere and asthenosphere. We reproduce the progressive decrease in thickness of the oceanic lithosphere at the trench. We measure plate kinematics, slab geometry and upper plate deformation. Our experiments reveal that the subduction of a thinning plate beneath a freely moving overriding continent favors a decrease of the subduction velocity and an increase of the oceanic slab dip. When the upper plate motion is imposed by lateral boundary conditions, the evolution of the subducting plate geometry largely differs depending on the velocity of the overriding plate: the larger its trenchward velocity, the smaller the superficial dip of the oceanic slab. A slab flattening episode may occur resulting from the combined effect of the subduction of an increasingly thinner plate and the trenchward motion of a fast overriding plate. Slab flattening would be marked by an increase of the distance between the trench and the volcanic arc in nature. This phenomenon may explain the reported Neogene eastward motion of the volcanic arc in the Southern Patagonia that occurred prior to the subduction of the Chile Ridge.

Integration of serpentine channels for microchip electrophoresis with a palladium decoupler and electrochemical detection

PubMed Central

Bowen, Amanda L; Martin, R. Scott

2010-01-01

While it has been shown that microchip electrophoresis with electrochemical detection can be used to separate and detect electroactive species, there is a need to increase the separation performance of these devices so that complex mixtures can be routinely analyzed. Previous work in microchip electrophoresis has demonstrated that increasing the separation channel length leads to an increase in resolution between closely eluting analytes. This paper details the use of lengthened serpentine microchannels for microchip electrophoresis and electrochemical detection where a palladium decoupler is used to ground the separation voltage so that the working electrodes remain in the fluidic network. In this work, palladium electrodepositions were used to increase the decoupler surface area and more efficiently dissipate hydrogen produced at the decoupler. Dopamine and norepinephrine, which only differ in structure by a hydroxyl group, were used as model analytes. It was found that increasing the separation channel length led to improvements in both resolution and the number of theoretical plates for these analytes. The use of a bi-layer valving device, where PDMS-based valves are utilized for the injection process, along with serpentine microchannels and amperometric detection resulted in a multi-analyte separation and an average of 28,700 theoretical plates. It was also shown that the increased channel length is beneficial when separating and detecting analytes from a high ionic strength matrix. This was demonstrated by monitoring the stimulated release of neuro-transmitters from a confluent layer of PC 12 cells. PMID:19739137

Instrument modifications that produced reduced plate heights <2 with sub-2 μm particles and 95% of theoretical efficiency at k=2 in supercritical fluid chromatography.

PubMed

Berger, Terry A

2016-04-29

The concept of peak fidelity was shown to be helpful in modeling tubing and detector cell dimensions. Connection tubing and flow cell variances were modeled to determine appropriate internal ID's, lengths, and volumes. A low dispersion plumbing configuration, based on these calculations, was assembled to replace the standard plumbing and produced the reported results. The modifications made were straightforward using commercially available parts. The full theoretical efficiency of a 3×100 mm column packed with 1.8 μm totally porous particles was achieved for the first time in supercritical fluid chromatography (SFC). Peak fidelity of >0.95 was maintained to below k=2. A reduced plate height as low as 1.87 was measured. Thus, true "ultra high performance" SFC was achieved, with the results a major improvement from all previous SFC reports. Since there were no efficiency losses, none could be attributed to thermal gradients caused by the expansion of the fluid over large pressure drops, under the conditions used. Similarly, changes in diffusion coefficients caused by significant decreases in density during expansion are apparently balanced by the increase in linear velocity, keeping the ratio between the diffusion coefficient and the linear velocity a constant. Changing modifier concentration to change retention was shown to not be a significant problem. All these issues have been a concern in the past. Diffusion coefficients, and viscosity data needs to be collected at high pressures before the actual limits of SFC can be discovered. Copyright © 2016 Elsevier B.V. All rights reserved.

RGB color calibration for quantitative image analysis: the "3D thin-plate spline" warping approach.

PubMed

Menesatti, Paolo; Angelini, Claudio; Pallottino, Federico; Antonucci, Francesca; Aguzzi, Jacopo; Costa, Corrado

2012-01-01

In the last years the need to numerically define color by its coordinates in n-dimensional space has increased strongly. Colorimetric calibration is fundamental in food processing and other biological disciplines to quantitatively compare samples' color during workflow with many devices. Several software programmes are available to perform standardized colorimetric procedures, but they are often too imprecise for scientific purposes. In this study, we applied the Thin-Plate Spline interpolation algorithm to calibrate colours in sRGB space (the corresponding Matlab code is reported in the Appendix). This was compared with other two approaches. The first is based on a commercial calibration system (ProfileMaker) and the second on a Partial Least Square analysis. Moreover, to explore device variability and resolution two different cameras were adopted and for each sensor, three consecutive pictures were acquired under four different light conditions. According to our results, the Thin-Plate Spline approach reported a very high efficiency of calibration allowing the possibility to create a revolution in the in-field applicative context of colour quantification not only in food sciences, but also in other biological disciplines. These results are of great importance for scientific color evaluation when lighting conditions are not controlled. Moreover, it allows the use of low cost instruments while still returning scientifically sound quantitative data.

An evaluation of a partial-walled laminar-flow operating room

PubMed Central

Whyte, W.; Shaw, B. H.; Freeman, M. A. R.

1974-01-01

This paper contains an assessment of the physical performance of a permanently installed down-flow laminar-flow operating room at the London Hospital. This system employs partial walls extending 0·76 m (2·5 ft.) from the ceiling, from which the air is allowed to issue freely downwards at an initial velocity of about 0·4 m./sec. (80 ft./min.). The usefulness of the partial wall, as compared with a free issuing system, was demonstrated and a comparison made with a fully walled system. It was shown that a fully walled system would be more efficient than a partial-walled system as there was a loss in air velocity of about 20-25% with the partial wall due to the nonconstrained flow of air. This loss would be reflected in an increase in airborne bacterial count and would mean that an increase of 20-25% in the air volume would be required to obtain the same conditions as with the full-walled system. Entrainment of contaminated air was demonstrated but it was concluded that this would be of little consequence in the centre of the clean area, i.e. at the wound site. Sterile instruments, etc., however, on the outside of the clean area, would be more liable to airborne contamination. Bacterial and dust airborne counts taken during total hip operations gave a very low average figure (0·3 bacteria/ft.3 or 10·5/m.3) from which we conclude that the system was about 30 times cleaner in terms of airborne bacteria than a well ventilated conventional operating-room. We concluded that although the partial-walled system was slightly less efficacious than a normal full-walled system, the freedom of movement and of communication for the operating team could in some circumstances outweigh this disadvantage. Sound levels were such that normal conversation was possible with little or no awareness of background noise. ImagesFig. 2Fig. 3Plate 2Plate 2Plate 3Plate 3Plate 1 PMID:4529595

Influence of end plates on aerodynamic characteristics of bluff bodies

NASA Astrophysics Data System (ADS)

Shmigirilov, Rodion; Ryabinin, Anatoly

2018-05-01

Aerodynamic characteristics of flat plate oriented normally to the flow are studied in the wind tunnel. The experiments are carried out without end plates and with round end plates of different diameter. We obtain that end plates increase the base pressure, the drag coefficient and decrease the length of recirculation region.

Measurements of induced radioactivity in some LDEF samples

NASA Technical Reports Server (NTRS)

Moss, C. E.; Reedy, R. C.

1992-01-01

Twenty-six stainless steel trunnion samples, five aluminum end support retainer plate samples, two aluminum keel plate samples, and two titanium clips were analyzed. The shielded high purity germanium detectors used had efficiencies of 33, 54, and 80 percent at 1332 keV. Detector efficiencies as a function of energy and corrections for self-absorption in the samples were determined with calibrated sources and unactivated control samples. Several measurements were made on most samples. In the trunnion samples, Mn-54 and Co-57 were seen and limits were obtained for other isotopes. The results agree well with 1-D activation calculations for an anisotropic trapped proton model. In the aluminum and titanium samples, Na-22 was detected. Other results are presented.

Measurements of induced radioactivity in some LDEF samples

NASA Technical Reports Server (NTRS)

Moss, C. E.; Reedy, R. C.

1991-01-01

Twenty-six stainless steel trunnion samples, five aluminum end support retainer plate samples, two aluminum keel plate samples, and two titanium clips were analyzed. The shielded high purity germanium detectors used had efficiencies of 33, 54, and 80 pcts. at 1332 keV. Detector efficiencies as a function of energy and corrections for self absorption in the samples were determined with calibrated sources, unactivated control samples, and calculations. Several measurements were made on most samples. In the trunnion samples, Mn-54 and Co-57 were seen and limits were obtained for other isotopes. The results agree well with 1-D activation calculations for an anisotropic trapped proton model. In the aluminum samples, Na-22 and Be-7 were seen. Other results are presented.

Glutamine Deprivation Causes Enhanced Plating Efficiency of a Herpes Simplex Virus Type 1 ICP0-Null Mutant ▿

PubMed Central

Bringhurst, Ryan M.; Dominguez, Antonia A.; Schaffer, Priscilla A.

2008-01-01

Isoleucine deprivation of cellular monolayers prior to infection has been reported to result in partial complementation of a herpes simplex virus type 1 (HSV-1) ICP0 null (ICP0−) mutant. We now report that glutamine deprivation alone is able to enhance the plating efficiency of an ICP0− virus and that isoleucine deprivation has little or no effect. Because a low glutamine level is associated with stress and because stress is known to induce reactivation, low levels of glutamine may be relevant to the reactivation of HSV-1 from latency. Additionally, we demonstrate that arginine and methionine deprivation result in partial complementation of the ICP0− virus. PMID:18768961

Preliminary study on zinc-air battery using zinc regeneration electrolysis with propanol oxidation as a counter electrode reaction

NASA Astrophysics Data System (ADS)

Wen, Yue-Hua; Cheng, Jie; Ning, Shang-Qi; Yang, Yu-Sheng

A zinc-air battery using zinc regeneration electrolysis with propanol oxidation as a counter electrode reaction is reported in this paper. It possesses functions of both zincate reduction and electrochemical preparation, showing the potential for increasing the electronic energy utilization. Charge/discharge tests and scanning electron microscopy (SEM) micrographs reveal that when a nickel sheet plated with the high-H 2-overpotential metal, cadmium, was used as the negative substrate electrode, the dendritic formation and hydrogen evolution are suppressed effectively, and granular zinc deposits become larger but relatively dense with the increase of charge time. The performance of batteries is favorable even if the charge time is as long as 5 h at the current density of 20 mA cm -2. Better discharge performance is achieved using a 'cavity-opening' configuration for the discharge cell rather than a 'gas-introducing' configuration. The highest energy efficiency is up to 59.2%. That is, the energy consumed by organic electro-synthesis can be recovered by 59.2%. Cyclic voltammograms show that the sintered nickel electrode exhibits a good electro-catalysis activity for the propanol oxidation. The increase of propanol concentration conduces to an enhancement in the organic electro-synthesis efficiency. The organic electro-synthesis current efficiency of 82% can be obtained.

Direct tests of micro channel plates as the active element of a new shower maximum detector

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

Ronzhin, A.; Los, S.; Ramberg, E.

2015-05-22

We continue the study of micro channel plates (MCP) as the active element of a shower maximum (SM) detector. We present below test beam results obtained with MCPs detecting directly secondary particles of an electromagnetic shower. The MCP efficiency to shower particles is close to 100%. Furthermore, the time resolution obtained for this new type of the SM detector is at the level of 40 ps.

Standardized performance tests of collectors of solar thermal energy: A selectively coated, flat-plate copper collector with one transparent cover and a tube-to-tube spacing of 5 5/8 inches

NASA Technical Reports Server (NTRS)

1976-01-01

This preliminary data report gives basic test results of a flat-plate solar collector whose performance was determined in the NASA-Lewis solar simulator. The collector was tested over ranges of inlet temperatures, fluxes and coolant flow rates. Collector efficiency is correlated in terms of inlet temperature and flux level.

Novel application for electrochemotherapy: Immersion of nasal cavity in dog.

PubMed

Suzuki, Daniela O H; Berkenbrock, José A; de Oliveira, Krishna D; Freytag, Jennifer O; Rangel, Marcelo M M

2017-08-01

Electrochemotherapy is a new modality of local cancer treatment that increases the delivery of chemotherapy drugs into tumor cells by applying intense electric fields. This novel electrochemotherapy application was applied as an adjuvant to surgery and eliminated intranasal tumors in dog. The treatment challenges are the surgery limitations due to anatomy and residual tumor in the bone cavity. Most of the tumoral mass on nasal cavity was surgically removed. The internal nasal cavity was immersed in liquid and bleomycin before applying electric field. The solution was necessary to increase the superficial contact between plate electrodes and residual tumor. The numerical study demonstrated electrochemotherapy efficiency in different clinical situations. The proximity between electrodes and bone (<3 mm) and bone irregularities affect the electric field distribution on tumoral tissue. The tumoral tissue around bone protuberances tends to be eliminated. Electrochemotherapy with plate electrodes inside the cavity might not be effective. Different values of electric conductivity solution were studied; the ideal value was 0.5 S/m. The numerical and experimental results confirm the successful application of electrochemotherapy on dog nasal cavity. © 2016 International Center for Artificial Organs and Transplantation and Wiley Periodicals, Inc.

Performance Assessment of a Plate Beam Splitter for Deep-Ultraviolet Raman Measurements with a Spatial Heterodyne Raman Spectrometer.

PubMed

Lamsal, Nirmal; Angel, S Michael

2017-06-01

In earlier works, we demonstrated a high-resolution spatial heterodyne Raman spectrometer (SHRS) for deep-ultraviolet (UV) Raman measurements, and showed its ability to measure UV light-sensitive compounds using a large laser spot size. We recently modified the SHRS by replacing the cube beam splitter (BS) with a custom plate beam splitter with higher light transmission, an optimized reflectance/transmission ratio, higher surface flatness, and better refractive index homogeneity than the cube beam splitter. Ultraviolet Raman measurements were performed using a SHRS modified to use the plate beam splitter and a matching compensator plate and compared to the previously described cube beam splitter setup. Raman spectra obtained using the modified SHRS exhibit much higher signals and signal-to-noise (S/N) ratio and show fewer spectral artifacts. In this paper, we discuss the plate beam splitter SHRS design features, the advantages over previous designs, and discuss some general SHRS issues such as spectral bandwidth, S/N ratio characteristics, and optical efficiency.

Plate-based diversity subset screening: an efficient paradigm for high throughput screening of a large screening file.

PubMed

Bell, Andrew S; Bradley, Joseph; Everett, Jeremy R; Knight, Michelle; Loesel, Jens; Mathias, John; McLoughlin, David; Mills, James; Sharp, Robert E; Williams, Christine; Wood, Terence P

2013-05-01

The screening files of many large companies, including Pfizer, have grown considerably due to internal chemistry efforts, company mergers and acquisitions, external contracted synthesis, or compound purchase schemes. In order to screen the targets of interest in a cost-effective fashion, we devised an easy-to-assemble, plate-based diversity subset (PBDS) that represents almost the entire computed chemical space of the screening file whilst comprising only a fraction of the plates in the collection. In order to create this file, we developed new design principles for the quality assessment of screening plates: the Rule of 40 (Ro40) and a plate selection process that insured excellent coverage of both library chemistry and legacy chemistry space. This paper describes the rationale, design, construction, and performance of the PBDS, that has evolved into the standard paradigm for singleton (one compound per well) high-throughput screening in Pfizer since its introduction in 2006.

Solar air heaters and their applications

NASA Technical Reports Server (NTRS)

Selcuk, M. K.

1977-01-01

The solar air heater appears to be the most logical choice, as far as the ultimate application of heating air to maintain a comfortable environment is concerned. One disadvantage of solar air heaters is the need for handling larger volumes of air than liquids due to the low density of air as a working substance. Another disadvantage is the low thermal capacity of air. In cases where thermal storage is needed, water is superior to air. Design variations of solar air heaters are discussed along with the calculation of the efficiency of a flat plate solar air heater, the performance of various collector types, and the applications of solar air heaters. Attention is given to collectors with nonporous absorber plates, collectors with porous absorbers, the performance of flat plate collectors with finned absorbers, a wire mesh absorber, and an overlapped glass plate air heater.

A Quad-Cantilevered Plate micro-sensor for intracranial pressure measurement.

PubMed

Lalkov, Vasko; Qasaimeh, Mohammad A

2017-07-01

This paper proposes a new design for pressure-sensing micro-plate platform to bring higher sensitivity to a pressure sensor based on piezoresistive MEMS sensing mechanism. The proposed design is composed of a suspended plate having four stepped cantilever beams connected to its corners, and thus defined as Quad-Cantilevered Plate (QCP). Finite element analysis was performed to determine the optimal design for sensitivity and structural stability under a range of applied forces. Furthermore, a piezoresistive analysis was performed to calculate sensor sensitivity. Both the maximum stress and the change in resistance of the piezoresistor associated with the QCP were found to be higher compared to previously published designs, and linearly related to the applied pressure as desired. Therefore, the QCP demonstrates greater sensitivity, and could be potentially used as an efficient pressure sensor for intracranial pressure measurement.

Evaluation of culture-based techniques and 454 pyrosequencing for the analysis of fungal diversity in potting media and organic fertilizers.

PubMed

Al-Sadi, A M; Al-Mazroui, S S; Phillips, A J L

2015-08-01

Potting media and organic fertilizers (OFs) are commonly used in agricultural systems. However, there is a lack of studies on the efficiency of culture-based techniques in assessing the level of fungal diversity in these products. A study was conducted to investigate the efficiency of seven culture-based techniques and pyrosequencing for characterizing fungal diversity in potting media and OFs. Fungal diversity was evaluated using serial dilution, direct plating and baiting with carrot slices, potato slices, radish seeds, cucumber seeds and cucumber cotyledons. Identity of all the isolates was confirmed on the basis of the internal transcribed spacer region of the ribosomal RNA (ITS rRNA) sequence data. The direct plating technique was found to be superior over other culture-based techniques in the number of fungal species detected. It was also found to be simple and the least time consuming technique. Comparing the efficiency of direct plating with 454 pyrosequencing revealed that pyrosequencing detected 12 and 15 times more fungal species from potting media and OFs respectively. Analysis revealed that there were differences between potting media and OFs in the dominant phyla, classes, orders, families, genera and species detected. Zygomycota (52%) and Chytridiomycota (60%) were the predominant phyla in potting media and OFs respectively. The superiority of pyrosequencing over cultural methods could be related to the ability to detect obligate fungi, slow growing fungi and fungi that exist at low population densities. The evaluated methods in this study, especially direct plating and pyrosequencing, may be used as tools to help detect and reduce movement of unwanted fungi between countries and regions. © 2015 The Society for Applied Microbiology.

Role of extracellular matrix in regulation of staurosporine-induced apoptosis in breast cancer cells.

PubMed

Vasaturo, F; Malacrino, C; Sallusti, E; Coppotelli, G; Birarelli, P; Giuffrida, A; Albonici, L; Simonelli, L; Modesti, A; Modesti, M; Scarpa, S

2005-04-01

Autocrine and paracrine mechanisms modulate the synthesis and secretion of extracellular matrix (ECM); moreover, each component of the ECM is capable of modulating the synthesis and release of other ECM molecules. Therefore, the synthesis of ECM glycoprotein fibronectin and laminin was studied in the human breast cancer cell lines MCF7 and MDA MB 23, plated on different ECM. Our results showed that the cells plated on a fibronectin substrate increased laminin synthesis: this event correlated with an increase in alpha2 and alpha3 integrin subunits. Staurosporine-induced apoptosis was then analyzed in the cell lines plated on different ECM. Staurosporine treatment determined the apoptosis of 35 and 33% respectively of MDA MB 231 and MCF7; these values increased to 60 and 64% in cells plated on laminin, to 48 and 63% in cells plated on fibronectin and to 64 and 69% in cells plated on matrigel. Moreover, staurosporine treatment decreased bcl-2 expression in the cells plated on fibronectin and laminin. Yet, staurosporine treatment determined PARP cleavage and PARP partial disappearance when the cells were plated on matrigel. Finally, a partial loss of function mutant Ras protein that activated only Raf pathway, was expressed in MCF7, in order to identify whether the increase of apoptosis induced by extracellular matrix involved the Raf/MAP kinase pathway. The increase of apoptosis of the cells plated on matrigel suggested that the activation of the Raf pathway is probably involved in the decrease of survival on matrigel. These data demonstrate that the modification of ECM modulates the apoptotic process of breast cancer cells and suggest that it is worthwhile to dissect the role of ECM in the control of apoptotic process.

Tubing modifications for countercurrent chromatography (CCC): Stationary phase retention and separation efficiency.

PubMed

Englert, Michael; Vetter, Walter

2015-07-16

Countercurrent chromatography (CCC) is a separation technique in which two immiscible liquid phases are used for the preparative purification of synthetic and natural products. In CCC the number of repetitive mixing and de-mixing processes, the retention of the stationary phase and the mass transfer between the liquid phases are significant parameters that influence the resolution and separation efficiency. Limited mass transfer is the main reason for peak broadening and a low number of theoretical plates along with impaired peak resolution in CCC. Hence, technical improvements with regard to column design and tubing modifications is an important aspect to enhance mixing and mass transfer. In this study we constructed a crimping tool which allowed us to make reproducible, semi-automated modifications of conventional round-shaped tubing. Six crimped tubing modifications were prepared, mounted onto multilayer coils which were subsequently installed in the CCC system. The stationary phase retention of the tubing modifications were compared to the conventional system with unmodified tubing in a hydrophobic, an intermediate and a hydrophilic two-phase solvent system. Generally, the tubing modifications provided higher capabilities to retain the stationary phase depending on the solvent system and flow rates. In the intermediate solvent system the separation efficiency was evaluated with a mixture of six alkyl p-hydroxybenzoates. The peak resolution could be increased up to 50% with one of the tubing modifications compared to the unmodified tubing. Using the most convincing tubing modification at fixed values for the stationary phase retention, a reasonable comparison to the unmodified tubing was achieved. The peak width could be reduced up to 49% and a strong positive impact at increased flow rates regarding peak resolution and theoretical plate number was observed compared to unmodified tubing. It could be concluded that the tubing modification enhanced the interphase mixing and mass transfer of the two phases by additional and more vigorous agitation. Copyright © 2015 Elsevier B.V. All rights reserved.

Strike-slip fault propagation and linkage via work optimization with application to the San Jacinto fault, California

NASA Astrophysics Data System (ADS)

Madden, E. H.; McBeck, J.; Cooke, M. L.

2013-12-01

Over multiple earthquake cycles, strike-slip faults link to form through-going structures, as demonstrated by the continuous nature of the mature San Andreas fault system in California relative to the younger and more segmented San Jacinto fault system nearby. Despite its immaturity, the San Jacinto system accommodates between one third and one half of the slip along the boundary between the North American and Pacific plates. It therefore poses a significant seismic threat to southern California. Better understanding of how the San Jacinto system has evolved over geologic time and of current interactions between faults within the system is critical to assessing this seismic hazard accurately. Numerical models are well suited to simulating kilometer-scale processes, but models of fault system development are challenged by the multiple physical mechanisms involved. For example, laboratory experiments on brittle materials show that faults propagate and eventually join (hard-linkage) by both opening-mode and shear failure. In addition, faults interact prior to linkage through stress transfer (soft-linkage). The new algorithm GROW (GRowth by Optimization of Work) accounts for this complex array of behaviors by taking a global approach to fault propagation while adhering to the principals of linear elastic fracture mechanics. This makes GROW a powerful tool for studying fault interactions and fault system development over geologic time. In GROW, faults evolve to minimize the work (or energy) expended during deformation, thereby maximizing the mechanical efficiency of the entire system. Furthermore, the incorporation of both static and dynamic friction allows GROW models to capture fault slip and fault propagation in single earthquakes as well as over consecutive earthquake cycles. GROW models with idealized faults reveal that the initial fault spacing and the applied stress orientation control fault linkage propensity and linkage patterns. These models allow the gains in efficiency provided by both hard-linkage and soft-linkage to be quantified and compared. Specialized models of interactions over the past 1 Ma between the Clark and Coyote Creek faults within the San Jacinto system reveal increasing mechanical efficiency as these fault structures change over time. Alongside this increasing efficiency is an increasing likelihood for single, larger earthquakes that rupture multiple fault segments. These models reinforce the sensitivity of mechanical efficiency to both fault structure and the regional tectonic stress orientation controlled by plate motions and provide insight into how slip may have been partitioned between the San Andreas and San Jacinto systems over the past 1 Ma.

Analog Modeling of the Interplay between Subduction and Lateral Extrusion in the European Alps

NASA Astrophysics Data System (ADS)

van Gelder, I. E.; Willingshofer, E.; Sokoutis, D.

2014-12-01

In the European Alps lateral extrusion is traditionally viewed as a lithospheric scale process that is related to northward indentation of a weak orogenic wedge (the eastern Alps) by a rigid indenter in upper plate position (the Adriatic plate). Critical for the efficiency of the extrusion process is the presence of a 'free boundary' at high angle to the indentation direction. The 'free boundary' in the eastern Alps is the result of the eastward extending Pannonian realm synchronous to indentation. However, indentation has become debatable as recent high-resolution tomography suggests that the Adriatic mantle lithosphere subducted under the extruding Alps. These findings raise first order questions related to: (a) the partitioning of deformation between lateral extrusion of the upper plate and coeval subduction of Adria, (b) the rheology of the lower and upper plates, and (c) the rheology of the plate contact controlling the amount of extrusion on the upper plate vs. accretion on the lower plate.In this analog modeling study, we couple for the first time lateral extrusion tectonics to subduction of the lower plate; thus, extrusion taking place in the upper plate. Within the lithospheric scale models, the lithospheres of the two plates are weakly coupled along an inclined boundary and have contrasting mantle lithosphere strength (stronger in the subducting plate). The interplay of extrusion vs subduction is inferred by varying the mechanical boundary conditions, e.g. the degree of resistance at the 'unconstrained' margin, the strength contrast between the upper and the lower plates and the width of the indented region.The experimental results emphasize that extrusion in the eastern Alps is compatible with coeval subduction of the Adriatic plate. The first experimental series suggests that the following mechanical conditions play a key role in the interplay between extrusion and subduction: (a) the extruding plate is weaker than the subducting plate, (b) the plate contact is weak in order to trigger the subduction of the lower plate, and (c) the eastern boundary is weak and thus allows for accommodating the extruding upper plate.

A novel ZVS high voltage power supply for micro-channel plate photomultiplier tubes

NASA Astrophysics Data System (ADS)

Pei, Chengquan; Tian, Jinshou; Liu, Zhen; Qin, Hong; Wu, Shengli

2017-04-01

A novel resonant high voltage power supply (HVPS) with zero voltage switching (ZVS), to reduce the voltage stress on switching devices and improve conversion efficiency, is proposed. The proposed HVPS includes a drive circuit, a transformer, several voltage multiplying circuits, and a regulator circuit. The HVPS contains several secondary windings that can be precisely regulated. The proposed HVPS performed better than the traditional resistor voltage divider, which requires replacing matching resistors resulting in resistor dispersibility in the Micro-Channel Plate (MCP). The equivalent circuit of the proposed HVPS was established and the operational principle analyzed. The entire switching element can achieve ZVS, which was validated by a simulation and experiments. The properties of this HVPS were tested including minimum power loss (240 mW), maximum power loss (1 W) and conversion efficiency (85%). The results of this research are that the proposed HVPS was suitable for driving the micro-channel plate photomultiplier tube (MCP-PMT). It was therefore adopted to test the MCP-PMT, which will be used in Daya Bay reactor neutrino experiment II in China.

Electromagnetic Design of a Magnetically-Coupled Spatial Power Combiner

NASA Technical Reports Server (NTRS)

Bulcha, B.; Cataldo, G.; Stevenson, T. R.; U-Yen, K.; Moseley, S. H.; Wollack, E. J.

2017-01-01

The design of a two-dimensional beam-combining network employing a parallel-plate superconducting waveguide with a mono-crystalline silicon dielectric is presented. This novel beam-combining network structure employs an array of magnetically coupled antenna elements to achieve high coupling efficiency and full sampling of the intensity distribution while avoiding diffractive losses in the multi-mode region defined by the parallel-plate waveguide. These attributes enable the structures use in realizing compact far-infrared spectrometers for astrophysical and instrumentation applications. When configured with a suitable corporate-feed power-combiner, this fully sampled array can be used to realize a low-sidelobe apodized response without incurring a reduction in coupling efficiency. To control undesired reflections over a wide range of angles in the finite-sized parallel-plate waveguide region, a wideband meta-material electromagnetic absorber structure is implemented. This adiabatic structure absorbs greater than 99 of the power over the 1.7:1 operational band at angles ranging from normal (0 degree) to near parallel (180 degree) incidence. Design, simulations, and application of the device will be presented.

Experimental investigation on the miniature mixed refrigerant cooler driven by a mini-compressor

NASA Astrophysics Data System (ADS)

Chen, Gaofei; Gong, Maoqiong; Wu, Yinong

2018-05-01

Three miniature Joule-Thomson cryogenic coolers and a testing set up were built to investigate the cooling performance in this work. Shell-and-tube heat exchanger and plate fin heat exchangers with rectangular micro channels were designed to achieve high specific surface area. The main processing technology of micro mixed refrigerant cooler (MMRC) was described. The design and fabrication processing of the plate fin heat exchangers were also described. The new developed micro plate-fin type heat exchanger shows high compactness with the specific heat surface larger than 1.0x104 m2/m3. The results of experimental investigations on miniature mixed refrigerant J-T cryogenic coolers driven by a Mini-Compressor were discussed. The performance evaluation and comparison of the three coolers was made to find out the features for each type of cooler. Expressions of refrigeration coefficient and exergy efficiency were pointed out. No-load temperature of about 112 K, and the cooling power of 4.0W at 118K with the input power of 120W is achieved. The exergy efficiency of the SJTC is 5.14%.

Study of the influence of substrate and spectrophotometer characteristics on the in vitro measurement of sunscreens efficiency.

PubMed

Couteau, C; Philippe, A; Vibet, M-A; Paparis, E; Coiffard, L

2018-05-16

All the methods used for the in vitro measurement of the SPF, the universal indicator of sunscreens efficiency, rely on a spectrophotometric analysis. What can vary about the experimental protocol used is mainly the substrate and the type of spectrophotometer chosen. We decided to work with polymethylmetacrylate plates that we analyzed using two spectrophotometers equipped with integrating spheres, the UV1000S and the UV2000 apparatus. Two marketed products were such tested, after spreading 2 mg/cm 2 on the plates, using one apparatus after another. We applied a non-parametric Wilcoxon test for paired data to the measures realized on 10 plates (as we systematically used the 2 apparatus), in order to compare the series of measures obtained with the two machines. This way, we were able to show a significant difference between the SPF values respectively obtained with the UV1000S and the UV2000 spectrophotometers. This difference could be explained by the decrease of the stray light in the case of the UV2000 apparatus. Copyright © 2017. Published by Elsevier B.V.

Conversion of evanescent Lamb waves into propagating waves via a narrow aperture edge.

PubMed

Yan, Xiang; Yuan, Fuh-Gwo

2015-06-01

This paper presents a quantitative study of conversion of evanescent Lamb waves into propagating in isotropic plates. The conversion is substantiated by prescribing time-harmonic Lamb displacements/tractions through a narrow aperture at an edge of a semi-infinite plate. Complex-valued dispersion and group velocity curves are employed to characterize the conversion process. The amplitude coefficient of the propagating Lamb modes converted from evanescent is quantified based on the complex reciprocity theorem via a finite element analysis. The power flow generated into the plate can be separated into radiative and reactive parts made on the basis of propagating and evanescent Lamb waves, where propagating Lamb waves are theoretically proved to radiate pure real power flow, and evanescent Lamb waves carry reactive pure imaginary power flow. The propagating power conversion efficiency is then defined to quantitatively describe the conversion. The conversion efficiency is strongly frequency dependent and can be significant. With the converted propagating waves from evanescent, sensors at far-field can recapture some localized damage information that is generally possessed in evanescent waves and may have potential application in structural health monitoring.

Controls on the T Phase Energy Fluxes Recorded on Juan Fernandez Island by Continental Seismic Wave Paths and Nazca Bathymetry

NASA Astrophysics Data System (ADS)

Sáez, Miguel; Ruiz, Sergio

2018-03-01

T phases from 54 South American earthquakes with Mw > 5.2 are observed at a broadband station on Juan Fernandez Island. We computed the T phase energy flux (TPEF) values of the seismograms. The TPEF values show a large dispersion that can be explained by considering the tectonic characteristics of the South American plate and the Nazca plate bathymetry. The TPEFs generated by the 2015 Illapel and 2017 Valparaíso seismic sequences were controlled by the positions of the interface events along the dip. The central and downdip interplate earthquakes were more efficient in the generation of T phases than the near-trench interplate earthquakes (depths of <15 km). The variations in the generation efficiency with depth are explained by the continental raypaths of the body waves and the incidence angles of waves entering the sound fixing and ranging channel. Additionally, we observed differences in the TPEFs from both earthquake sequences that were controlled by seamounts atop the Nazca plate along the T phase paths.

New high-efficiency silicon solar cells

NASA Technical Reports Server (NTRS)

Daud, T.; Crotty, G. T.

1985-01-01

A design for silicon solar cells was investigated as an approach to increasing the cell open-circuit voltage and efficiency for flat-plate terrestrial photovoltaic applications. This deviates from past designs, where either the entire front surface of the cell is covered by a planar junction or the surface is textured before junction formation, which results in an even greater (up to 70%) junction area. The heavily doped front region and the junction space charge region are potential areas of high recombination for generated and injected minority carriers. The design presented reduces junction area by spreading equidiameter dot junctions across the surface of the cell, spaced about a diffusion length or less from each other. Various dot diameters and spacings allowed variations in total junction area. A simplified analysis was done to obtain a first-order design optimization. Efficiencies of up to 19% can be obtained. Cell fabrication involved extra masking steps for selective junction diffusion, and made surface passivation a key element in obtaining good collection. It also involved photolithography, with line widths down to microns. A method is demonstrated for achieving potentially high open-circuit voltages and solar-cell efficiencies.

Comparative study of As (III) and Zn (II) removal from aqueous solutions using Philippine natural zeolite and alumina

NASA Astrophysics Data System (ADS)

Olegario-Sanchez, Eleanor; Pelicano, Christian Mark

2017-12-01

Herein, the heavy metal removal efficiency of Philippine natural zeolite is investigated through a comparative study with commercial alumina (Al2O3). XRD results revealed a high purity crystalline γ-Al2O3 and a natural zeolite having clinoptilolite (Na,K,Ca)2-3Al3(Al,Si)2Si13O36.12H2O and mordenite (Ca, Na2, K2)Al2Si10O24.7H2O as primary component minerals. Micro-pores and plate-like structures were observed on the surface of the natural zeolite. The natural zeolite has shown three times higher removal efficiency for Zn2+ ion than alumina. On the other hand, alumina exhibited comparable but smaller removal efficiency for As3+ as with that of natural zeolite. Alumina showed a higher capability of increasing the pH of both solutions compared with the natural zeolite. Based on removal efficiency and adsorbent costs, Philippine natural zeolite could be used as a low-cost alternative for wastewater treatment.

Avionics Box Cold Plate Damage Prevention

NASA Technical Reports Server (NTRS)

Stambolian, Damon B.; Larchar, Steven W.; Henderson, Gena; Tran, Donald; Barth, Tim

2012-01-01

Problem Introduction: 1. Prevent Cold Plate Damage in Space Shuttle. 1a. The number of cold plate problems had increased from an average of 16.5 per/year between 1990 through 2000, to an average of 39.6 per year between 2001through 2005. 1b. Each complete set of 80 cold plates cost approximately $29 million, an average of $362,500 per cold plate. 1c It takes four months to produce a single cold plate. 2. Prevent Cold Plate Damage in Future Space Vehicles.

Glow discharge plasma pretreatment enhances osteoclast differentiation and survival on titanium plates.

PubMed

Kawai, Hiroyuki; Shibata, Yo; Miyazaki, Takashi

2004-05-01

Despite the fact that several reports have demonstrated osteoclast activity on various bioactive ceramics, osteoclast functions on surface-modified titanium have not come under focus. This study aimed to examine whether the increasing surface energy of glow discharge plasma (GDP) involved in protein adhesion containing the RGD (Arg-Gly-Asp) sequence affects osteoclast responses on titanium plates. We examined osteoclast differentiation and survival rates on titanium plates with and without GDP. The amounts of osteoclasts on titanium plates were not increased by GDP after 1 week. However, osteoclast differentiation was greatly activated by GDP pretreatment, as tartrate-resistant acid phosphatase synthesis significantly increased on the titanium plates with GDP. Additionally, since the presence of osteoclasts was detected only on the titanium plates with GDP, even after 4h cultivation in a coculture test, the osteoclasts survival rate was increased by GDP pretreatment. As osteoclast responses were affected even on surface modified metallic materials, we concluded that novel approaches are needed not only for osteoclastic resorption on ceramic materials but also for osteoclast responses on surface-modified metallic materials.

Modeling of the heat transfer performance of plate-type dispersion nuclear fuel elements

NASA Astrophysics Data System (ADS)

Ding, Shurong; Huo, Yongzhong; Yan, XiaoQing

2009-08-01

Considering the mutual actions between fuel particles and the metal matrix, the three-dimensional finite element models are developed to simulate the heat transfer behaviors of dispersion nuclear fuel plates. The research results indicate that the temperatures of the fuel plate might rise more distinctly with considering the particle swelling and the degraded surface heat transfer coefficients with increasing burnup; the local heating phenomenon within the particles appears when their thermal conductivities are too low. With rise of the surface heat transfer coefficients, the temperatures within the fuel plate decrease; the temperatures of the fuel plate are sensitive to the variations of the heat transfer coefficients whose values are lower, but their effects are weakened and slight when the heat transfer coefficients increase and reach a certain extent. Increasing the heat generation rate leads to elevating the internal temperatures. The temperatures and the maximum temperature differences within the plate increase along with the particle volume fractions. The surface thermal flux goes up along with particle volume fractions and heat generation rates, but the effects of surface heat transfer coefficients are not evident.

Importance of the accuracy of experimental data in the nonlinear chromatographic determination of adsorption energy distributions

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

Stanley, B.J.; Guiochon, G.

1994-11-01

Adsorption energy distributions (AEDs) are calculated from the classical, fundamental integral equation of adsorption using adsorption isotherms and the expectation-maximization method of parameter estimation. The adsorption isotherms are calculated from nonlinear elution profiles obtained from gas chromatographic data using the characteristic points method of finite concentration chromatography. Porous layer open tubular capillary columns are used to support the adsorbent. The performance of these columns is compared to that of packed columns in terms of their ability to supply accurate isotherm data and AEDs. The effect of the finite column efficiency and the limited loading factor on the accuracy of themore » estimated energy distributions is presented. This accuracy decreases with decreasing efficiency, and approximately 5000 theoretical plates are needed when the loading factor, L[sub f], equals 0.56 for sampling of a unimodal Gaussian distribution. Increasing L[sub f] further increases the contribution of finite efficiency to the AED and causes a divergence at the low-energy endpoint if too high. This occurs as the retention time approaches the holdup time. Data are presented for diethyl ether adsorption on porous silica and its C-18-bonded derivative. 36 refs., 8 figs., 2 tabs.« less

In situ synthesis of CdS/CdWO4/WO3 heterojunction films with enhanced photoelectrochemical properties

NASA Astrophysics Data System (ADS)

Zhan, Faqi; Li, Jie; Li, Wenzhang; Yang, Yahui; Liu, Wenhua; Li, Yaomin

2016-09-01

CdS/CdWO4/WO3 heterojunction films on fluorine-doped tin oxide (FTO) substrates are for the first time prepared as an efficient photoanode for photoelectrochemical (PEC) hydrogen generation by an in situ conversion process. The samples are characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), ultraviolet visible spectrometry (UV-vis) and X-ray photoelectron spectroscopy (XPS). The CdS hollow spheres (∼80 nm) sensitized WO3 plate film with a CdWO4 buffer-layer exhibits increased visible light absorption and a significantly improved photoelectrochemical performance. The photocurrent density at 0 V (vs. Ag/AgCl) of the CdS/CdWO4/WO3 anode is ∼3 times higher than that of the CdWO4/WO3 anode, and ∼9 times higher than that of pure WO3 under illumination. The highest incident-photon-to-current-efficiency (IPCE) value increased from 16% to 63% when the ternary heterojunction was formed. This study demonstrates that the synthesis of ternary composite photocatalysts by the in situ conversion process may be a promising approach to achieve high photoelectric conversion efficiency.

Deflection and trapping of a counter-rotating vortex pair by a flat plate

NASA Astrophysics Data System (ADS)

Nitsche, Monika

2017-12-01

The interaction of a counter-rotating vortex pair (dipole) with a flat plate in its path is studied numerically. The vortices are initially separated by a distance D (dipole size) and placed far upstream of a plate of length L . The plate is centered on the dipole path and inclined relative to it at an incident angle βi. At first, the plate is held fixed in place. The vortices approach the plate, travel around it, and then leave as a dipole with unchanged velocity but generally a different travel direction, measured by a transmitted angle βt. For certain plate angles the transmitted angle is highly sensitive to changes in the incident angle. The sensitivity increases as the dipole size decreases relative to the plate length. In fact, for sufficiently small values of D /L , singularities appear: near critical values of βi, the dipole trajectory undergoes a topological discontinuity under changes of βi or D /L . The discontinuity is characterized by a jump in the winding number of one vortex around the plate, and in the time that the vortices take to leave the plate. The jumps occur repeatedly in a self-similar, fractal fashion, within a region near the critical values of βi, showing the existence of incident angles that trap the vortices, which never leave the plate. The number of these trapping regions increases as the parameter D /L decreases, and the dependence of the motion on βi becomes increasingly complex. The simulations thus show that even in this apparently simple scenario, the inviscid dynamics of a two-point-vortex system interacting with a stationary wall is surprisingly rich. The results are then applied to separate an incoming stream of dipoles by an oscillating plate.

Polyethyleneimine Capped Silver Nanoclusters as Efficient Antibacterial Agents.

PubMed

Xu, Dong; Wang, Qingyun; Yang, Tao; Cao, Jianzhong; Lin, Qinlu; Yuan, Zhiqin; Li, Le

2016-03-18

Development of efficient antibacterial agents is critical for human health. In the present study, we investigated the antibacterial activity of polyethyleneimine (PEI)-capped silver nanoclusters (PEI-AgNCs), based on the fact that nanoclusters normally have higher surface-to-volume ratios than traditional nanomaterials and PEI itself has a strong antimicrobial capacity. We synthesized stable silver nanoclusters by altering PEI molecular weight from 0.6 kDa to 25 kDa and characterized them by UV-Vis absorption and fluorescence spectroscopy and high resolution transmission electron microscopy. The sizes of AgNCs were around 2 nm in diameter and were little influenced by the molecular weight of PEIs. The antibacterial abilities of the four PEI-AgNCs were explored on agar plate and in liquid systems. Our results revealed that the antibacterial activity of PEI-AgNCs is excellent and the reduction of PEI molecular weight could result in the increased antibacterial capacity of PEI-AgNCs. Such proposed new materials might be useful as efficient antibacterial agents in practical clinical applications.

Analytic and Computational Perspectives of Multi-Scale Theory for Homogeneous, Laminated Composite, and Sandwich Beams and Plates

NASA Technical Reports Server (NTRS)

Tessler, Alexander; Gherlone, Marco; Versino, Daniele; DiSciuva, Marco

2012-01-01

This paper reviews the theoretical foundation and computational mechanics aspects of the recently developed shear-deformation theory, called the Refined Zigzag Theory (RZT). The theory is based on a multi-scale formalism in which an equivalent single-layer plate theory is refined with a robust set of zigzag local layer displacements that are free of the usual deficiencies found in common plate theories with zigzag kinematics. In the RZT, first-order shear-deformation plate theory is used as the equivalent single-layer plate theory, which represents the overall response characteristics. Local piecewise-linear zigzag displacements are used to provide corrections to these overall response characteristics that are associated with the plate heterogeneity and the relative stiffnesses of the layers. The theory does not rely on shear correction factors and is equally accurate for homogeneous, laminated composite, and sandwich beams and plates. Regardless of the number of material layers, the theory maintains only seven kinematic unknowns that describe the membrane, bending, and transverse shear plate-deformation modes. Derived from the virtual work principle, RZT is well-suited for developing computationally efficient, C(sup 0)-continuous finite elements; formulations of several RZT-based elements are highlighted. The theory and its finite element approximations thus provide a unified and reliable computational platform for the analysis and design of high-performance load-bearing aerospace structures.

Analytic and Computational Perspectives of Multi-Scale Theory for Homogeneous, Laminated Composite, and Sandwich Beams and Plates

NASA Technical Reports Server (NTRS)

Tessler, Alexander; Gherlone, Marco; Versino, Daniele; Di Sciuva, Marco

2012-01-01

This paper reviews the theoretical foundation and computational mechanics aspects of the recently developed shear-deformation theory, called the Refined Zigzag Theory (RZT). The theory is based on a multi-scale formalism in which an equivalent single-layer plate theory is refined with a robust set of zigzag local layer displacements that are free of the usual deficiencies found in common plate theories with zigzag kinematics. In the RZT, first-order shear-deformation plate theory is used as the equivalent single-layer plate theory, which represents the overall response characteristics. Local piecewise-linear zigzag displacements are used to provide corrections to these overall response characteristics that are associated with the plate heterogeneity and the relative stiffnesses of the layers. The theory does not rely on shear correction factors and is equally accurate for homogeneous, laminated composite, and sandwich beams and plates. Regardless of the number of material layers, the theory maintains only seven kinematic unknowns that describe the membrane, bending, and transverse shear plate-deformation modes. Derived from the virtual work principle, RZT is well-suited for developing computationally efficient, C0-continuous finite elements; formulations of several RZT-based elements are highlighted. The theory and its finite elements provide a unified and reliable computational platform for the analysis and design of high-performance load-bearing aerospace structures.

Influence of tip end-plate on noise of small axial fan

NASA Astrophysics Data System (ADS)

Mao, Hongya; Wang, Yanping; Lin, Peifeng; Jin, Yingzi; Setoguchi, Toshiaki; Kim, Heuy Dong

2017-02-01

In this work, tip end-plate is used to improve the noise performance of small axial fans. Both numerical simulations and experimental methods were adopted to study the fluid flow and noise level of axial fans. Four modified models and the prototype are simulated. Influences of tip end-plate on static characteristics, internal flow field and noise of small axial fans are analyzed. The results show that on basis of the prototype, the model with the tip end-plate of 2 mm width and changed length achieved best noise performance. The overall sound pressure level of the model with the tip end-plate of 2 mm width and changed length is 2.4 dB less than that of the prototype at the monitoring point in specified far field. It is found that the mechanism of noise reduction is due to the decrease of vorticity variation on the surface of blades caused by the tip end-plate. Compared with the prototype, the static pressure of the model with the tip end-plate of 2 mm width and changed length at design flow rate decreases by 2 Pa and the efficiency decreases by 0.8%. It is concluded that the method of adding tip end-plate to impeller blades has a positive influence on reducing noise, but it may diminish the static characteristics of small axial fan to some extent.

Long-term weathering effects on the thermal performance of the Libbey-Owens-Ford (liquid) solar collector

NASA Technical Reports Server (NTRS)

1979-01-01

Thermal performance tests were conducted on the Libbey-Owens-Ford liquid collector, following long term exposure to natural weathering conditions. Visual inspection of the collector, prior to the retest, indicated noticeable clouding of the inner cover glass, probably resulting from outgassing of the insulation. The absorber plate also showed some discoloration. The test results indicated that performance degradation had occurred at inlet temperatures significantly above ambient. The change in the slope of the efficiency curve, from the original data, is a direct indicator of an increase in the collector heat loss coefficient.

Daylighting with Mirror Light Pipes and with Fluorescent Planar Concentrators. First Results from the Demonstration Project Stuttgart-Hohenheim

NASA Astrophysics Data System (ADS)

Zastrow, Armin; Wittwer, Volker

1987-02-01

Efficient daylighting systems have recently attracted increasing interest due to their potential for saving a condiderable amount of electrical energy used for lighting purposes. In this paper we discuss the properties of daylighting systems based on either fluorescent planar concentrators (FPC's) and transparent light guiding plates or light pipes coated with a highly reflective silver coated plastic film (3M Silverlux film). First results on daylighting systems in the students' living quarters in Stuttgart-Hohenheim will be presented. This is a demonstration project which is supported by the Commission of the European Communities.

Photovoltaic applications of Compound Parabolic Concentrator (CPC)

NASA Technical Reports Server (NTRS)

Winston, R.

1975-01-01

The use of a compound parabolic concentrator as field collector, in conjunction with a primary focusing concentrator for photovoltaic applications is studied. The primary focusing concentrator can be a parabolic reflector, an array of Fresnel mirrors, a Fresnel lens or some other lens. Silicon solar cell grid structures are proposed that increase efficiency with concentration up to 10 suns. A ray tracing program has been developed to determine energy distribution at the exit of a compound parabolic concentrator. Projected total cost of a CPC/solar cell system will be between 4 and 5 times lower than for flat plate silicon cell arrays.

A Fresnel zone plate collimator: potential and aberrations

NASA Astrophysics Data System (ADS)

Menz, Benedikt; Bräuninger, Heinrich; Burwitz, Vadim; Hartner, Gisela; Predehl, Peter

2015-09-01

A collimator, that parallelizes an X-ray beam, provides a significant improvement of the metrology to characterize X-ray optics for space instruments at MPE's PANTER X-ray test facility. A Fresnel zone plate was selected as a collimating optic, as it meets a good angular resolution < 0.1n combined with a large active area > 10 cm2. Such an optic is ideally suited to illuminate Silicon Pore Optic (SPO) modules as proposed for ATHENA. This paper provides the theoretic description of such a Fresnel zone plate especially considering resolution and efficiency. Based on the theoretic results the collimator setup performance is analyzed and requirements for fabrication and alignment are calculated.

Optimization Design of Bipolar Plate Flow Field in PEM Stack

NASA Astrophysics Data System (ADS)

Wen, Ming; He, Kanghao; Li, Peilong; Yang, Lei; Deng, Li; Jiang, Fei; Yao, Yong

2017-12-01

A new design of bipolar plate flow field in proton exchange membrane (PEM) stack was presented to develop a high-performance transfer efficiency of the two-phase flow. Two different flow fields were studied by using numerical simulations and the performance of the flow fields was presented. the hydrodynamic properties include pressure gap between inlet and outlet, the Reynold’s number of the two types were compared based on the Navier-Stokes equations. Computer aided optimization software was implemented in the design of experiments of the preferable flow field. The design of experiments (DOE) for the favorable concept was carried out to study the hydrodynamic properties when changing the design parameters of the bipolar plate.

MULTI-PLATE IONIZATION CHAMBER FOR THE DETECTION OF SLOW NEUTRONS

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

Bubzanowski, A.; Grotowski, K.

1957-01-01

A description is given of an ionization chamber, the electrodes of which are coated with a layer of natural boron of thickness 3 mg/cm/sup 2/. Each electrode of the chamber consists of three disks, placed between plates of the other electrodes. The capacitance between the electrodes does not exceed 15 micromicrofarads. The technology of coating the layer is as follows: the boron is mixed with alcohol and a small amount of Canada balsam and is coated in the form of an emulsion on the plates. The chamber efficiency is approximately 2%. The filler is argon at atmospheric pressure. The durationmore » of the output pulses after forming is approximately 5 microseconds.« less

Thermal buckling optimisation of composite plates using firefly algorithm

NASA Astrophysics Data System (ADS)

Kamarian, S.; Shakeri, M.; Yas, M. H.

2017-07-01

Composite plates play a very important role in engineering applications, especially in aerospace industry. Thermal buckling of such components is of great importance and must be known to achieve an appropriate design. This paper deals with stacking sequence optimisation of laminated composite plates for maximising the critical buckling temperature using a powerful meta-heuristic algorithm called firefly algorithm (FA) which is based on the flashing behaviour of fireflies. The main objective of present work was to show the ability of FA in optimisation of composite structures. The performance of FA is compared with the results reported in the previous published works using other algorithms which shows the efficiency of FA in stacking sequence optimisation of laminated composite structures.

Robotic Patterning a Superhydrophobic Surface for Collective Cell Migration Screening.

PubMed

Pang, Yonggang; Yang, Jing; Hui, Zhixin; Grottkau, Brian E

2018-04-01

Collective cell migration, in which cells migrate as a group, is fundamental in many biological and pathological processes. There is increasing interest in studying the collective cell migration in high throughput. Cell scratching, insertion blocker, and gel-dissolving techniques are some methodologies used previously. However, these methods have the drawbacks of cell damage, substrate surface alteration, limitation in medium exchange, and solvent interference. The superhydrophobic surface, on which the water contact angle is greater than 150 degrees, has been recently utilized to generate patterned arrays. Independent cell culture areas can be generated on a substrate that functions the same as a conventional multiple well plate. However, so far there has been no report on superhydrophobic patterning for the study of cell migration. In this study, we report on the successful development of a robotically patterned superhydrophobic array for studying collective cell migration in high throughput. The array was developed on a rectangular single-well cell culture plate consisting of hydrophilic flat microwells separated by the superhydrophobic surface. The manufacturing process is robotic and includes patterning discrete protective masks to the substrate using 3D printing, robotic spray coating of silica nanoparticles, robotic mask removal, robotic mini silicone blocker patterning, automatic cell seeding, and liquid handling. Compared with a standard 96-well plate, our system increases the throughput by 2.25-fold and generates a cell-free area in each well non-destructively. Our system also demonstrates higher efficiency than conventional way of liquid handling using microwell plates, and shorter processing time than manual operating in migration assays. The superhydrophobic surface had no negative impact on cell viability. Using our system, we studied the collective migration of human umbilical vein endothelial cells and cancer cells using assays of endpoint quantification, dynamic cell tracking, and migration quantification following varied drug treatments. This system provides a versatile platform to study collective cell migration in high throughput for a broad range of applications.

Method for controlling protein crystallization

NASA Technical Reports Server (NTRS)

Noever, David A. (Inventor)

1993-01-01

A method and apparatus for controlling the crystallization of protein by solvent evaporation including placing a drop of protein solution between and in contact with a pair of parallel plates and driving one of the plates toward and away from the other plate in a controlled manner to adjust the spacing between the plates is presented. The drop of solution forms a liquid cylinder having a height dependent upon the plate spacing thereby effecting the surface area available for solvent evaporation. When the spacing is close, evaporation is slow. Evaporation is increased by increasing the spacing between the plates until the breaking point of the liquid cylinder. One plate is mounted upon a fixed post while the other plate is carried by a receptacle movable relative to the post and driven by a belt driven screw drive. The temperature and humidity of the drop of protein solution are controlled by sealing the drop within the receptacle and mounting a heater and dessicant within the receptacle.

Numerical Analysis of Stress Concentration in Isotropic and Laminated Plates with Inclined Elliptical Holes

NASA Astrophysics Data System (ADS)

Khechai, Abdelhak; Tati, Abdelouahab; Belarbi, Mohamed Ouejdi; Guettala, Abdelhamid

2018-03-01

The design of high-performance composite structures frequently includes discontinuities to reduce the weight and fastener holes for joining. Understanding the behavior of perforated laminates is necessary for structural design. In the current work, stress concentrations taking place in laminated and isotropic plates subjected to tensile load are investigated. The stress concentrations are obtained using a recent quadrilateral finite element of four nodes with 32 DOFs. The present finite element (PE) is a combination of two finite elements. The first finite element is a linear isoparametric membrane element and the second is a high precision Hermitian element. One of the essential objectives of the current investigation is to confirm the capability and efficiency of the PE for stress determination in perforated laminates. Different geometric parameters, such as the cutout form, sizes and cutout orientations, which have a considerable effect on the stress values, are studied. Using the present finite element formulation, the obtained results are found to be in good agreement with the analytical findings, which validates the capability and the efficiency of the proposed formulation. Finally, to understand the material parameters effect such as the orientation of fibers and degree of orthotropy ratio on the stress values, many figures are presented using different ellipse major to minor axis ratio. The stress concentration values are considerably affected by increasing the orientation angle of the fibers and degree of orthotropy.

Degradation of reactive blue 19 by needle-plate non-thermal plasma in different gas atmospheres: Kinetics and responsible active species study assisted by CFD calculations.

PubMed

Sun, Yu; Liu, Yanan; Li, Rui; Xue, Gang; Ognier, Stéphanie

2016-07-01

This study investigated the degradation of a model organic compound, reactive blue (RB-19), in aqueous solution using a needle-plate non-thermal plasma (NTP) reactor, which was operated using three gas atmospheres (Ar, air, O2) at room temperature and atmospheric pressure. The relative discharge and degradation parameters, including the peak to peak applied voltage, power, ozone generation, pH, decolorization rates, energy density and the total organic carbon (TOC) reduction were analyzed to determine the various dye removal efficiencies. The decolorization rate for Ar, air and O2 were 59.9%, 49.6% and 89.8% respectively at the energy density of 100 kJ/L. The best TOC reduction was displayed by Ar with about 8.8% decrease, and 0% with O2 and air atmospheres. This phenomenon could be explained by the formation of OH• and O3 in the Ar and O2 atmospheres, which are responsible for increased mineralization and efficient decolorization. A one-dimension model was developed using software COMSOL to simulate the RB-19-ozone reaction and verify the experiments by comparing the simulated and experimental results. It was determined that ozone plays the most important role in the dye removal process, and the ozone contribution rate ranged from 0.67 to 0.82. Copyright © 2016 Elsevier Ltd. All rights reserved.

High-speed fiber laser cutting of thick stainless steel for dismantling tasks

NASA Astrophysics Data System (ADS)

Shin, Jae Sung; Oh, Seong Yong; Park, Hyunmin; Chung, Chin-Man; Seon, Sangwoo; Kim, Taek-Soo; Lee, Lim; Choi, Byung-Seon; Moon, Jei-Kwon

2017-09-01

A high-speed fiber laser cutting technology of thick steels for dismantling tasks was achieved using a 6-kW fiber laser system. At first, a new cutting head for efficient cutting of thick steels was developed, which was composed by a collimator with a focal length of 160 mm and mirror-type focusing objects with a long focal length of 600 mm. The long focal length of the focusing object made it possible for the beam size to be small through the thick cutting material and the cutting efficiency was expected to increase compared with the short focal length. In addition, folding the beam facilitated the compact cutting head with a size of 160 mm (width) × 80 mm (height) × 640 mm (length) and a weight of 6.9 kg. In the cutting experiment, the laser beam was delivered to the cutting head by a 25-m long process fiber with a core diameter of 100 μm. The cutting performances were studied against the thicknesses of stainless steel plates. A maximum cutting speed of 72 mm/min was obtained for the 60-mm thick stainless steel plate cutting and the cut specimen showed an excellent kerf shape and a narrow kerf width. To the best of our knowledge, this cutting speed was higher than other previously reported results when cutting with a 6-kW laser power.

Environmental friendly crush-magnetic separation technology for recycling metal-plated plastics from end-of-life vehicles.

PubMed

Xue, Mianqiang; Li, Jia; Xu, Zhenming

2012-03-06

Metal-plated plastics (MPP), which are important from the standpoint of aesthetics or even performance, are increasingly employed in a wide variety of situations in the automotive industry. Serious environmental problems will be caused if they are not treated appropriately. Therefore, recycling of MPP is an important subject not only for resource recycling but also for environmental protection. This work represents a novel attempt to deal with the MPP. A self-designed hammer crusher was used to liberate coatings from the plastic substrate. The size distribution of particles was analyzed and described by the Rosin-Rammler function model. The optimum retaining time of materials in the crusher is 3 min. By this time, the liberation rate of the materials can reach 87.3%. When the density of the suspension is 31,250 g/m(3), the performance of liberation is the best. Two-step magnetic separation was adopted to avoid excessive crushing and to guarantee the quality of products. Concerning both the separation efficiency and grade of products, the optimum rotational speed of the magnetic separator is 50-70 rpm. On the basis of the above studies about the liberating and separating behavior of the materials, a continuous recycling system (the technology of crush-magnetic separation) is developed. This recycling system provides a feasible method for recycling MPP efficiently, economically, and environmentally.

A motor-driven ventricular assist device controlled with an optical encoder system.

PubMed

Nakamura, T; Hayashi, K; Yamane, H

1993-01-01

An electric motor-driven ventricular assist device has been developed for long-term use inside the body. The system is composed of a pusher-plate-type blood pump and an actuator consisting of an electrical motor and a ball screw. Cyclic change of the direction of motor rotation makes a back-and-forth axial movement of the ball screw shaft. The shaft, which is detached from the pump diaphragm, pushes the diaphragm via a pusher plate to eject blood during systole; blood is sucked by the diaphragm resilience during diastole. Using the output signals from a newly designed, incremental-type, miniature optical rotary encoder mounted inside the actuator, the input voltage of the motor is optimally controlled referring to the phase difference between the current position of the moving rotor and the electrical reference signal of the rotation generated by a microprocessor-based controller. In vitro performance tests indicated that the system fulfills required specifications. The maximum efficiency was 11%, which was about twice as high as that obtained with the previous open-loop prototype system. In the air, the surface temperature of the actuator elevated to 20 degrees C above the room temperature. An acute in vivo test showed its feasibility as a left ventricular assist device. Analysis of the energy loss in each component of the system indicated that redesign and precise assembly of the mechanical parts could increase the system efficiency.

Incorporation of metal-organic framework HKUST-1 into porous polymer monolithic capillary columns to enhance the chromatographic separation of small molecules.

PubMed

Yang, Shengchao; Ye, Fanggui; Lv, Qinghui; Zhang, Cong; Shen, Shufen; Zhao, Shulin

2014-09-19

Metal-organic framework (MOF) HKUST-1 nanoparticles have been incorporated into poly(glycidyl methacrylate-co-ethylene dimethacrylate) (HKUST-1-poly(GMA-co-EDMA)) monoliths to afford stationary phases with enhanced chromatographic performance of small molecules in the reversed phase capillary liquid chromatography. The effect of HKUST-1 nanoparticles in the polymerization mixture on the performance of the monolithic column was explored in detail. While the bare poly(GMA-co-EDMA) monolith exhibited poor resolution (Rs<1.0) and low efficiency (800-16,300plates/m), addition of a small amount of HKUST-1 nanoparticles to the polymerization mixture provide high increased resolution (Rs≥1.3) and high efficiency ranged from 16,300 to 44,300plates/m. Chromatographic performance of HKUST-1-poly(GMA-co-EDMA) monolith was demonstrated by separation of various analytes including polycyclic aromatic hydrocarbons, ethylbenzene and styrene, phenols and aromatic acids using a binary polar mobile phase (CH3CN/H2O). The HKUST-1-poly(GMA-co-EDMA) monolith displayed enhanced hydrophobic and π-π interaction characteristics in the reversed phase separation of test analytes compared to the bare poly(GMA-co-EDMA) monolith. The experiment results showed that HKUST-1-poly(GMA-co-EDMA) monoliths are an alternative to enhance the chromatographic separation of small molecules. Copyright © 2014 Elsevier B.V. All rights reserved.

Radiation-hard ceramic Resistive Plate Chambers for forward TOF and T0 systems

NASA Astrophysics Data System (ADS)

Akindinov, A.; Dreyer, J.; Fan, X.; Kämpfer, B.; Kiselev, S.; Kotte, R.; Garcia, A. Laso; Malkevich, D.; Naumann, L.; Nedosekin, A.; Plotnikov, V.; Stach, D.; Sultanov, R.; Voloshin, K.

2017-02-01

Resistive Plate Chambers with ceramic electrodes are the main candidates for a use in precise multi-channel timing systems operating in high-radiation conditions. We report the latest R&D results on these detectors aimed to meet the requirements of the forward T0 counter at the CBM experiment. RPC design, gas mixture, limits on the bulk resistivity of ceramic electrodes, efficiency, time resolution, counting rate capabilities and ageing test results are presented.

Mechanical excitation of rodlike particles by a vibrating plate.

PubMed

Trittel, Torsten; Harth, Kirsten; Stannarius, Ralf

2017-06-01

The experimental realization and investigation of granular gases usually require an initial or permanent excitation of ensembles of particles, either mechanically or electromagnetically. One typical method is the energy supply by a vibrating plate or container wall. We study the efficiency of such an excitation of cylindrical particles by a sinusoidally oscillating wall and characterize the distribution of kinetic energies of excited particles over their degrees of freedom. The influences of excitation frequency and amplitude are analyzed.

Characteristics of square pore and low noise microchannel plate stacks. [for x-ray astronomy

NASA Technical Reports Server (NTRS)

Siegmund, Oswald H. W.; Marsh, Daniel; Stock, Joseph; Gaines, Geoffrey

1992-01-01

An evaluation is conducted of several square-pore microchannel plates (MCPs) with either 25- or 85-micron diameter pores and 80:1 or 50:1 channel length/diameter ratio. Flat field measurements show that the 25-micron-pored MCPs, unlike those with 85-micron pores, exhibit periodic modulation; this may be due to the MCP stacking configurations. Attention is given to the relative quantum detection efficiency advantages of the two MCPs.

Performance optimization of plate heat exchangers with chevron plates

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

Muley, A.; Manglik, R.M.

1999-07-01

The enhanced heat transfer performance of a chevron plate heat exchanger (PHE) is evaluated employing (1) energy-conservation based performance evaluation criteria (PECs), and (2) the second-law based minimization of entropy generation principle. Single-phase laminar and turbulent flow convection for three different chevron-plate arrangements are considered. The influence of plate surface corrugation characteristics and their stack arrangements on the heat exchanger's thermal-hydraulic performance is delineated. Based on the different figures of merit, the results show that the extent of heat transfer enhancement increases with flow Re and chevron angle {beta} in laminar flow, but it diminishes with increasing Re in turbulentmore » flows. With up to 2.9 times higher Q, 48% lower A, and entropy generation number N{sub s,a} {lt} 1, relative to an equivalent flat-plate pack, chevron plates are found to be especially suitable in the low to medium flow rates range (20 {le} Re {le} 2,000). Also, there appears to be no significant advantage of using a mixed-plate over a symmetric-plate arrangement.« less

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.

Thrust generation by a heaving flexible foil: Resonance, nonlinearities, and optimality

NASA Astrophysics Data System (ADS)

Paraz, Florine; Schouveiler, Lionel; Eloy, Christophe

2016-01-01

Flexibility of marine animal fins has been thought to enhance swimming performance. However, despite numerous experimental and numerical studies on flapping flexible foils, there is still no clear understanding of the effect of flexibility and flapping amplitude on thrust generation and swimming efficiency. Here, to address this question, we combine experiments on a model system and a weakly nonlinear analysis. Experiments consist in immersing a flexible rectangular plate in a uniform flow and forcing this plate into a heaving motion at its leading edge. A complementary theoretical model is developed assuming a two-dimensional inviscid problem. In this model, nonlinear effects are taken into account by considering a transverse resistive drag. Under these hypotheses, a modal decomposition of the system motion allows us to predict the plate response amplitude and the generated thrust, as a function of the forcing amplitude and frequency. We show that this model can correctly predict the experimental data on plate kinematic response and thrust generation, as well as other data found in the literature. We also discuss the question of efficiency in the context of bio-inspired propulsion. Using the proposed model, we show that the optimal propeller for a given thrust and a given swimming speed is achieved when the actuating frequency is tuned to a resonance of the system, and when the optimal forcing amplitude scales as the square root of the required thrust.

Feasibility of Actively Cooled Silicon Nitride Airfoil for Turbine Applications Demonstrated

NASA Technical Reports Server (NTRS)

Bhatt, Ramakrishna T.

2001-01-01

Nickel-base superalloys currently limit gas turbine engine performance. Active cooling has extended the temperature range of service of nickel-base superalloys in current gas turbine engines, but the margin for further improvement appears modest. Therefore, significant advancements in materials technology are needed to raise turbine inlet temperatures above 2400 F to increase engine specific thrust and operating efficiency. Because of their low density and high-temperature strength and thermal conductivity, in situ toughened silicon nitride ceramics have received a great deal of attention for cooled structures. However, the high processing costs and low impact resistance of silicon nitride ceramics have proven to be major obstacles for widespread applications. Advanced rapid prototyping technology in combination with conventional gel casting and sintering can reduce high processing costs and may offer an affordable manufacturing approach. Researchers at the NASA Glenn Research Center, in cooperation with a local university and an aerospace company, are developing actively cooled and functionally graded ceramic structures. The objective of this program is to develop cost-effective manufacturing technology and experimental and analytical capabilities for environmentally stable, aerodynamically efficient, foreign-object-damage-resistant, in situ toughened silicon nitride turbine nozzle vanes, and to test these vanes under simulated engine conditions. Starting with computer aided design (CAD) files of an airfoil and a flat plate with internal cooling passages, the permanent and removable mold components for gel casting ceramic slips were made by stereolithography and Sanders machines, respectively. The gel-cast part was dried and sintered to final shape. Several in situ toughened silicon nitride generic airfoils with internal cooling passages have been fabricated. The uncoated and thermal barrier coated airfoils and flat plates were burner rig tested for 30 min without and with air cooling. Without cooling, the surface temperature of the flat plate reached approximately 2350 F. Starting with computer aided design (CAD) files of an airfoil and a flat plate with internal cooling passages, the permanent and removable mold components for gel casting ceramic slips were made by stereolithography and Sanders machines, respectively. The gel-cast part was dried and sintered to final shape. Several in situ toughened silicon nitride generic airfoils with internal cooling passages have been fabricated. The uncoated and thermal barrier coated airfoils and flat plates were burner rig tested for 30 min without and with air cooling. Without cooling, the surface temperature of the flat plate reached approximately 2350 F. With cooling, the surface temperature decreased to approximately 1910 F--a drop of approximately 440 F. This preliminary study demonstrates that a near-net-shape silicon nitride airfoil can be fabricated and that silicon nitride can sustain severe thermal shock and the thermal gradients induced by cooling and, thus, is a viable candidate for cooled components.

Notch Sensitivity of Woven Ceramic Matrix Composites Under Tensile Loading: An Experimental, Analytical, and Finite Element Study

NASA Technical Reports Server (NTRS)

Haque, A.; Ahmed, L.; Ware, T.; Jeelani, S.; Verrilli, Michael J. (Technical Monitor)

2001-01-01

The stress concentrations associated with circular notches and subjected to uniform tensile loading in woven ceramic matrix composites (CMCs) have been investigated for high-efficient turbine engine applications. The CMC's were composed of Nicalon silicon carbide woven fabric in SiNC matrix manufactured through polymer impregnation process (PIP). Several combinations of hole diameter/plate width ratios and ply orientations were considered in this study. In the first part, the stress concentrations were calculated measuring strain distributions surrounding the hole using strain gages at different locations of the specimens during the initial portion of the stress-strain curve before any microdamage developed. The stress concentration was also calculated analytically using Lekhnitskii's solution for orthotropic plates. A finite-width correction factor for anisotropic and orthotropic composite plate was considered. The stress distributions surrounding the circular hole of a CMC's plate were further studied using finite element analysis. Both solid and shell elements were considered. The experimental results were compared with both the analytical and finite element solutions. Extensive optical and scanning electron microscopic examinations were carried out for identifying the fracture behavior and failure mechanisms of both the notched and notched specimens. The stress concentration factors (SCF) determined by analytical method overpredicted the experimental results. But the numerical solution underpredicted the experimental SCF. Stress concentration factors are shown to increase with enlarged hole size and the effects of ply orientations on stress concentration factors are observed to be negligible. In all the cases, the crack initiated at the notch edge and propagated along the width towards the edge of the specimens.

Tribological properties of amorphous hydrogenated (a-C:H) and hydrogen-free tetrahedral (ta-C) diamond-like carbon coatings under jatropha biodegradable lubricating oil at different temperatures

NASA Astrophysics Data System (ADS)

Mobarak, H. M.; Masjuki, H. H.; Mohamad, E. Niza; Kalam, M. A.; Rashedul, H. K.; Rashed, M. M.; Habibullah, M.

2014-10-01

The application of diamond-like carbon (DLC) coatings on automotive components is emerging as a favorable strategy to address the recent challenges in the industry. DLC coatings can effectively lower the coefficient of friction (CoF) and wear rate of engine components, thereby improving their fuel efficiency and durability. The lubrication of ferrous materials can be enhanced by a large amount of unsaturated and polar components of oils. Therefore, the interaction between nonferrous coatings (e.g., DLC) and vegetable oil should be investigated. A ball-on-plate tribotester was used to run the experiments. Stainless steel plates coated with amorphous hydrogenated (a-C:H) DLC and hydrogen-free tetrahedral (ta-C) DLC that slide against 440C stainless steel ball were used to create a ball-on-plate tribotester. The wear track was investigated through scanning electron microscopy. Energy dispersive and X-ray photoelectron spectroscopies were used to analyze the tribofilm inside the wear track. Raman analysis was performed to investigate the structural changes in the coatings. At high temperatures, the CoF in both coatings decreased. The wear rate, however, increased in the a-C:H but decreased in the ta-C DLC-coated plates. The CoF and the wear rate (coated layer and counter surface) were primarily influenced by the graphitization of the coating. Tribochemical films, such as polyphosphate glass, were formed in ta-C and acted as protective layers. Therefore, the wear rate of the ta-C DLC was lower than that of the-C:H DLC.

Sensitivity of cultured skin fibroblasts from patients with neurofibromatosis to DNA-damaging agents

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

Woods, W.G.; McKenzie, B.; Letourneau, M.A.

Neurofibromatosis (NF) is an autosomal dominant disorder associated with various constitutional abnormalities as well as a striking predisposition for malignant and nonmalignant neoplasms, both in cells originating in and not originating in the neural crest. We have examined the sensitivity of cultured skin fibroblasts from patients with neurofibromatosis to several types of DNA damage. Fibroblasts in Dulbecco's modified Eagle's medium were plated at 10(2) to 2 X 10(4) cells per 75 cm2 tissue culture plates, and exposed to various doses of gamma radiation (leads to DNA scission), actinomycin D, or mitomycin C. Cells were reincubated for 15 to 40 daysmore » until surviving colonies exhibited greater than 30-50 cells. Plates were then stained with 1% methylene blue and the colonies counted, with surviving fraction determined relative to plating efficiency. Nine skin fibroblast cell strains from normal individuals were studied as controls. One neurofibromatosis (NF) cell strain, SB23, exhibited normal sensitivity to all three DNA-damaging agents studied in early (7-8) and middle (12-13) in vitro passage. Strain GM0622, on the other hand, exhibited normal sensitivity to the three DNA-damaging agents studied at early passage, but showed a significant decrease in survival after exposure to both gamma radiation (D0 = 106 rad) and actinomycin D (D0 = 0.024 mcg/ml) with increasing passage. Strain GM1639 exhibited decreased survival after actinomycin D exposure at early passage (D0 = 0.017 mcg/ml), with normal survival after exposure to gamma radiation and mitomycin C at the same passage.« less

Analysis of the influence of the milling machine throw-out plate surfacing and structure design on throwing material

NASA Astrophysics Data System (ADS)

Fang, Yuanbin; Sha, Hongwei; Yu, Yunmin; Chen, Bing

2018-03-01

Material composition, hardness and wear properties of the throw-out plate improved are analysed on a road milling machine. At the same time, analyse the tissue and performance of Fe based alloy named Fe60 cladding layer using the plasma surfacing method. And the original and improved throw-out plates are analysed throwing material effect by the dynamic analysis. Then the throw-out plate samples are verified. The results show that Fe60 powder is selected as surface strengthening material. By the improved structure, the hardness of the throw-out plate increases from 14.6HRC to 57.5HRC, and the wear resistance increases from 0.452g-1 to 16.393g-1. At the same time, it increases from 3263 to 3433 to fall into the collecting material number of milling machine. It provides important guidance for structure design and process design of the milling machine throw-out plate.

High-precision laser microcutting and laser microdrilling using diffractive beam-splitting and high-precision flexible beam alignment

NASA Astrophysics Data System (ADS)

Zibner, F.; Fornaroli, C.; Holtkamp, J.; Shachaf, Lior; Kaplan, Natan; Gillner, A.

2017-08-01

High-precision laser micro machining gains more importance in industrial applications every month. Optical systems like the helical optics offer highest quality together with controllable and adjustable drilling geometry, thus as taper angle, aspect ratio and heat effected zone. The helical optics is based on a rotating Dove-prism which is mounted in a hollow shaft engine together with other optical elements like wedge prisms and plane plates. Although the achieved quality can be interpreted as extremely high the low process efficiency is a main reason that this manufacturing technology has only limited demand within the industrial market. The objective of the research studies presented in this paper is to dramatically increase process efficiency as well as process flexibility. During the last years, the average power of commercial ultra-short pulsed laser sources has increased significantly. The efficient utilization of the high average laser power in the field of material processing requires an effective distribution of the laser power onto the work piece. One approach to increase the efficiency is the application of beam splitting devices to enable parallel processing. Multi beam processing is used to parallelize the fabrication of periodic structures as most application only require a partial amount of the emitted ultra-short pulsed laser power. In order to achieve highest flexibility while using multi beam processing the single beams are diverted and re-guided in a way that enables the opportunity to process with each partial beam on locally apart probes or semimanufactures.

Operando lithium plating quantification and early detection of a commercial LiFePO4 cell cycled under dynamic driving schedule

NASA Astrophysics Data System (ADS)

Anseán, D.; Dubarry, M.; Devie, A.; Liaw, B. Y.; García, V. M.; Viera, J. C.; González, M.

2017-07-01

Lithium plating is considered one of the most detrimental phenomenon in lithium ion batteries (LIBs), as it increases cell degradation and might lead to safety issues. Plating induced LIB failure presents a major concern for emerging applications in transportation and electrical energy storage. Hence, the necessity to operando monitor, detect and analyze lithium plating becomes critical for safe and reliable usage of LIB systems. Here, we report in situ lithium plating analyses for a commercial graphite||LiFePO4 cell cycled under dynamic stress test (DST) driving schedule. We designed a framework based on incremental capacity (IC) analysis and mechanistic model simulations to quantify degradation modes, relate their effects to lithium plating occurrence and assess cell degradation. The results show that lithium plating was induced by large loss of active material on the negative electrode that eventually led the electrode to over-lithiate. Moreover, when lithium plating emerged, we quantified that the loss of lithium inventory pace was increased by a factor of four. This study illustrates the benefits of the proposed framework to improve lithium plating analysis. It also discloses the symptoms of lithium plating formation, which prove valuable for novel, online strategies on early lithium plating detection.

Experimental investigation on the dynamic response of clamped corrugated sandwich plates subjected to underwater impulsive loadings

NASA Astrophysics Data System (ADS)

Huang, Wei; Zhang, Wei; Li, Dacheng; Hypervelocity Impact Research Center Team

2015-06-01

Corrugated sandwich plates are widely used in marine industry because such plates have high strength-to-weight ratios and blast resistance. The laboratory-scaled fluid-structure interaction experiments are performed to demonstrate the shock resistance of solid monolithic plates and corrugated sandwich plates by quantifying the permanent transverse deflection at mid-span of the plates as a function of impulsive loadings per areal mass. Sandwich structures with 6mm-thick and 10mm-thick 3003 aluminum corrugated core and 5A06 face sheets are compared with the 5A06 solid monolithic plates in this paper. The dynamic deformation of plates are captured with the the 3D digital speckle correlation method (DIC). The results affirm that sandwich structures show a 30% reduction in the maximum plate deflection compare with a monolithic plate of identical mass per unit area, and the peak value of deflection effectively reduced by increasing the thickness core. The failure modes of sandwich plates consists of core crushing, imprinting, stretch tearing of face sheets, bending and permanent deformation of entire structure with the increasing impulsive loads, and the failure mechanisms are analyzed with the postmortem panels and dynamic deflection history captured by cameras. National Natural Science Foundation of China (NO.: 11372088).

Biomechanical analysis of clavicle hook plate implantation with different hook angles in the acromioclavicular joint.

PubMed

Hung, Li-Kun; Su, Kuo-Chih; Lu, Wen-Hsien; Lee, Cheng-Hung

2017-08-01

A clavicle hook plate is a simple and effective method for treating acromioclavicular dislocation and distal clavicle fractures. However, subacromial osteolysis and peri-implant fractures are complicated for surgeons to manage. This study uses finite element analysis (FEA) to investigate the post-implantation biomechanics of clavicle hook plates with different hook angles. This FEA study constructed a model with a clavicle, acromion, clavicle hook plate, and screws to simulate the implantation of clavicle hook plates at different hook angles (90°, 95°, 100°, 105°, and 110°) for treating acromioclavicular joint dislocations. This study investigated the biomechanics of the acromion, clavicle, hook plate, and screws. A smaller hook angle increases the stress on the middle third of the clavicle. A larger hook angle increases the force exerted by the clavicle hook plate on the acromion. The screw at the most medial position on the plate generated the highest stress. The highest stress on the implanted clavicle hook plate was on the turning corner of the hook. A clavicle hook plate with different hook angles may induce different biomechanical behaviors in the clavicle and acromion. Orthopedic surgeons must select a suitable clavicle hook plate based on the anatomical structure of each patient.

Initiation of the Pyrenean plate boundary fault and its effect on the near- and far-field deformation of the European plate

NASA Astrophysics Data System (ADS)

Dielforder, Armin; Frasca, Gianluca; Ford, Mary

2017-04-01

The European plate was affected by contractional deformation events in Late Cretaceous time. This is recorded by inception of thrusting and foreland basin subsidence in the Pyrenean realm, and inversion of Mesozoic rift systems in the interior of the European plate. It is widely accepted that the plate-wide deformation resulted from the onset of NE-directed convergence of Africa-Iberia relative to Europe, and a strong mechanical coupling of the plates, which allowed the transfer of stresses far into Europe. Geological data from both the Pyrenean orogen and the interior of the European plate indicate, however, that these conditions persisted only for 15-20 Myr and that Europe experienced a plate-wide stress relaxation during Paleocene time. Although a slow down in plate convergence between Africa and Europe and North Atlantic continental rifting were proposed as potential causes for the stress relaxation, the subject has remained controversial. In particular, none of the mechanisms seem to be suitable to explain the required changes in the mechanical coupling of Iberian and European plates and the associated stress transfer. Here we propose a new model for the Upper Cretaceous to Paleocene tectonic evolution of the European plate, which takes the temporal evolution of the Pyrenean plate boundary fault into account. Based on plate reconstructions, geological field-data, and restored cross-sections we argue that the plate boundary fault initiated during the Upper Cretaceous within the exhumed mantle domain situated between the rifted margins of the Iberian and European plates. At the transition from the Late Cretaceous to Paleocene, the mantle domain was closed and the rifted margins collided. This evolution was associated with a substantial change in the fault rheology leading to an overall decrease in the plate coupling force. During Paleocene time, the plate coupling force was efficiently balanced by the gravitational push of the European plate, leading to a near neutral stress state in the upper plate and the observed plate-wide stress relaxation in Europe. This study is part of the Orogen research program and conducted in close collaboration with the BRGM (Bureau de Recherches Géologiques et Minières), the CNRS (Centre National de la Recherche Scientifique), and Total.

Thermal-hydraulic behavior of a mixed chevron single-pass plate-and-frame heat exchanger

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

Manglik, R.M.; Muley, A.

1995-12-31

Effective heat exchange is very critical for improving the process efficiency and operating economy of chemical and process plants. Here, experimental friction factor and heat transfer data for single-phase water flows in a plate-and-frame heat exchanger are presented. A mixed chevron plate arrangement with {beta} = 30{degree}/60{degree} in a single-pass U-type, counterflow configuration is employed. The friction factor and heat transfer data are for isothermal flow and cooling conditions, respectively, and the flow rates correspond to transition and turbulent flow regimes (300 < Re < 6,000 and 2.4 < Pr < 4.5). Based on these data, Nusselt number and frictionmore » factor correlations for fully developed turbulent flows (Re {ge} 1,000) are presented. The results highlight the effects of {beta} on the thermal-hydraulic performance, transition to turbulent flows, and the relative impact of using symmetric or mixed chevron plate arrangements.« less

In-situ data collection at the photon factory macromolecular crystallography beamlines

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

Yamada, Yusuke, E-mail: yusuke.yamada@kek.jp; Matsugaki, Naohiro; Kato, Ryuichi

Crystallization trial is one of the most important but time-consuming steps in macromolecular crystallography, and in-situ diffraction experiment has a capability to make researchers to proceed this step more efficiently. At the Photon Factory, a new tabletop diffractometer for in-situ diffraction experiments has been developed. It consists of XYZ translation stages with a plate handler, an on-axis viewing system and a plate rack with a capacity for ten crystallization plates. These components sit on a common plate and are able to be placed on the existing diffractometer table. The CCD detector with a large active area and a pixel arraymore » detector with a small active area are used for acquiring diffraction images from crystals. Dedicated control software and a user interface have also been developed. The new diffractometer has been operational for users and used for evaluation of crystallization screening since 2014.« less

Elasto-plastic bending of cracked plates, including the effects of crack closure. Ph.D. Thesis

NASA Technical Reports Server (NTRS)

Jones, D. P.

1972-01-01

A capability for solving elasto-plastic plate bending problems is developed using assumptions consistent with Kirchhoff plate theory. Both bending and extensional modes of deformation are admitted with the two modes becoming coupled as yielding proceeds. Equilibrium solutions are obtained numerically by determination of the stationary point of a functional which is analogous to the potential strain energy. The stationary value of the functional for each load increment is efficiently obtained through use of the conjugate gradient. This technique is applied to the problem of a large centrally through cracked plate subject to remote circular bending. Comparison is drawn between two cases of the bending problem. The first neglects the possibility of crack face interference with bending, and the second includes a kinematic prohibition against the crack face from passing through the symmetry plane. Results are reported which isolate the effects of elastoplastic flow and crack closure.

Evaluation of the methods for enumerating coliform bacteria from water samples using precise reference standards.

PubMed

Wohlsen, T; Bates, J; Vesey, G; Robinson, W A; Katouli, M

2006-04-01

To use BioBall cultures as a precise reference standard to evaluate methods for enumeration of Escherichia coli and other coliform bacteria in water samples. Eight methods were evaluated including membrane filtration, standard plate count (pour and spread plate methods), defined substrate technology methods (Colilert and Colisure), the most probable number method and the Petrifilm disposable plate method. Escherichia coli and Enterobacter aerogenes BioBall cultures containing 30 organisms each were used. All tests were performed using 10 replicates. The mean recovery of both bacteria varied with the different methods employed. The best and most consistent results were obtained with Petrifilm and the pour plate method. Other methods either yielded a low recovery or showed significantly high variability between replicates. The BioBall is a very suitable quality control tool for evaluating the efficiency of methods for bacterial enumeration in water samples.

Potential Evaluation of Solar Heat Assisted Desiccant Hybrid Air Conditioning System

NASA Astrophysics Data System (ADS)

Tran, Thien Nha; Hamamoto, Yoshinori; Akisawa, Atsushi; Kashiwagi, Takao

The solar thermal driven desiccant dehumidification-absorption cooling hybrid system has superior advantage in hot-humid climate regions. The reasonable air processing of desiccant hybrid air conditioning system and the utility of clean and free energy make the system environment friendly and energy efficient. The study investigates the performance of the desiccant dehumidification air conditioning systems with solar thermal assistant. The investigation is performed for three cases which are combinations of solar thermal and absorption cooling systems with different heat supply temperature levels. Two solar thermal systems are used in the study: the flat plate collector (FPC) and the vacuum tube with compound parabolic concentrator (CPC). The single-effect and high energy efficient double-, triple-effect LiBr-water absorption cooling cycles are considered for cooling systems. COP of desiccant hybrid air conditioning systems are determined. The evaluation of these systems is subsequently performed. The single effect absorption cooling cycle combined with the flat plate collector solar system is found to be the most energy efficient air conditioning system.

Testing and Optimizing a Stove-Powered Thermoelectric Generator with Fan Cooling.

PubMed

Zheng, Youqu; Hu, Jiangen; Li, Guoneng; Zhu, Lingyun; Guo, Wenwen

2018-06-07

In order to provide heat and electricity under emergency conditions in off-grid areas, a stove-powered thermoelectric generator (STEG) was designed and optimized. No battery was incorporated, ensuring it would work anytime, anywhere, as long as combustible materials were provided. The startup performance, power load feature and thermoelectric (TE) efficiency were investigated in detail. Furthermore, the heat-conducting plate thickness, cooling fan selection, heat sink dimension and TE module configuration were optimized. The heat flow method was employed to determine the TE efficiency, which was compared to the predicted data. Results showed that the STEG can supply clean-and-warm air (625 W) and electricity (8.25 W at 5 V) continuously at a temperature difference of 148 °C, and the corresponding TE efficiency was measured to be 2.31%. Optimization showed that the choice of heat-conducting plate thickness, heat sink dimensions and cooling fan were inter-dependent, and the TE module configuration affected both the startup process and the power output.

One-way mode transmission in one-dimensional phononic crystal plates

NASA Astrophysics Data System (ADS)

Zhu, Xuefeng; Zou, Xinye; Liang, Bin; Cheng, Jianchun

2010-12-01

We investigate theoretically the band structures of one-dimensional phononic crystal (PC) plates with both antisymmetric and symmetric structures, and show how unidirectional transmission behavior can be obtained for either antisymmetric waves (A modes) or symmetric waves (S modes) by exploiting mode conversion and selection in the linear plate systems. The theoretical approach is illustrated for one PC plate example where unidirectional transmission behavior is obtained in certain frequency bands. Employing harmonic frequency analysis, we numerically demonstrate the one-way mode transmission for the PC plate with finite superlattice by calculating the steady-state displacement fields under A modes source (or S modes source) in forward and backward direction, respectively. The results show that the incident waves from A modes source (or S modes source) are transformed into S modes waves (or A modes waves) after passing through the superlattice in the forward direction and the Lamb wave rejections in the backward direction are striking with a power extinction ratio of more than 1000. The present structure can be easily extended to two-dimensional PC plate and efficiently encourage practical studies of experimental realization which is believed to have much significance for one-way Lamb wave mode transmission.