The relationship between the force and separation of miniature magnets used in dentistry.

PubMed

Darvell, Brian W; Gilding, Brian H

2018-06-01

Miniature magnets are used in dentistry, principally for the retention of prosthetic devices. The relationship between force and separation of a magnet and its keeper, or, equivalently, two such magnets, has been neither defined theoretically nor described practically in any detail suitable for these applications. The present paper addresses this lacuna. A magnet is considered as a conglomeration of magnetic poles distributed over a surface or a solid in three-dimensional space, with the interaction of poles governed by the Coulomb law. This leads to a suite of mathematical models. These models are analysed for their description of the relationship between the force and the separation of two magnets. It is shown that at a large distance of separation, an inverse power law must apply. The power is necessarily integer and at least two. All possibilities are exhausted. Complementarily, under reasonable assumptions, it is shown that at a small distance of separation, the force remains finite. The outcome is in accordance with practical experience, and at odds with the use of simple conceptual models. Consequences relevant to the usage of magnets in dentistry are discussed. Copyright © 2018 The Academy of Dental Materials. Published by Elsevier Inc. All rights reserved.

Correlating Resolving Power, Resolution, and Collision Cross Section: Unifying Cross-Platform Assessment of Separation Efficiency in Ion Mobility Spectrometry.

PubMed

Dodds, James N; May, Jody C; McLean, John A

2017-11-21

Here we examine the relationship among resolving power (R p ), resolution (R pp ), and collision cross section (CCS) for compounds analyzed in previous ion mobility (IM) experiments representing a wide variety of instrument platforms and IM techniques. Our previous work indicated these three variables effectively describe and predict separation efficiency for drift tube ion mobility spectrometry experiments. In this work, we seek to determine if our previous findings are a general reflection of IM behavior that can be applied to various instrument platforms and mobility techniques. Results suggest IM distributions are well characterized by a Gaussian model and separation efficiency can be predicted on the basis of the empirical difference in the gas-phase CCS and a CCS-based resolving power definition (CCS/ΔCCS). Notably traveling wave (TWIMS) was found to operate at resolutions substantially higher than a single-peak resolving power suggested. When a CCS-based R p definition was utilized, TWIMS was found to operate at a resolving power between 40 and 50, confirming the previous observations by Giles and co-workers. After the separation axis (and corresponding resolving power) is converted to cross section space, it is possible to effectively predict separation behavior for all mobility techniques evaluated (i.e., uniform field, trapped ion mobility, traveling wave, cyclic, and overtone instruments) using the equations described in this work. Finally, we are able to establish for the first time that the current state-of-the-art ion mobility separations benchmark at a CCS-based resolving power of >300 that is sufficient to differentiate analyte ions with CCS differences as small as 0.5%.

Space shuttle abort separation pressure investigation. Volume 1, Part A: Booster data at Mach 5

NASA Technical Reports Server (NTRS)

Trimmer, L. L.; Love, D. A.; Rampy, J. M.; Decker, J. P.; Blackwell, K. L.; Strike, W. T.

1972-01-01

Pressure data obtained from a joint Langley Research Center (LaRC)/Marshall Space Flight Center (MSFC) Space Shuttle about stage separation wind tunnel test are presented. The .00556 scale models of the McDonnell-Douglas orbiter and booster configurations were tested in proximity in Tunnel A of the Von Karman Facility (VKF), Arnold Engineering Development Center (AEDC). Mach numbers were 5.0, 3.0, and 2.0 and nominal Reynolds numbers were 1.09, 1.60, and 1.74 million per foot, respectively. Pressure data were obtained for the booster upper surface and orbiter lower surface at angles of attack of -10 deg, -5, 0, 5, and 10 deg for zero degrees sideslip. The models were tested at incidence angles of 0 and 5 deg for several separation distances and power conditions. Plug nozzles utilizing air were used to simulate booster and orbiter plumes at various altitudes along a nominal ascent trajectory. Powered conditions were 100, 50, and 0 percent of full power for the orbiter and 100, 50 and 0 percent of full power for the booster. Data were also obtained with the booster canard off in close proximity.

Equipment of the binary-cycle geothermal power unit at the Pauzhet geothermal power station

NASA Astrophysics Data System (ADS)

Tomarov, G. V.; Nikol'skii, A. I.; Semenov, V. N.; Shipkov, A. A.

2014-06-01

The equipment of and technological processes in the pilot industrial model of the domestically produced binary-cycle geothermal power unit operating on the discharge separate at the Pauzhet geothermal power station are considered. The development principles, the design and operational features, and the data on selecting the metal in manufacturing the main equipment of the 2.5-MW binary power unit of the geothermal power station are described.

Electricity generation and transmission planning in deregulated power markets

NASA Astrophysics Data System (ADS)

He, Yang

This dissertation addresses the long-term planning of power generation and transmission facilities in a deregulated power market. Three models with increasing complexities are developed, primarily for investment decisions in generation and transmission capacity. The models are presented in a two-stage decision context where generation and transmission capacity expansion decisions are made in the first stage, while power generation and transmission service fees are decided in the second stage. Uncertainties that exist in the second stage affect the capacity expansion decisions in the first stage. The first model assumes that the electric power market is not constrained by transmission capacity limit. The second model, which includes transmission constraints, considers the interactions between generation firms and the transmission network operator. The third model assumes that the generation and transmission sectors make capacity investment decisions separately. These models result in Nash-Cournot equilibrium among the unregulated generation firms, while the regulated transmission network operator supports the competition among generation firms. Several issues in the deregulated electric power market can be studied with these models such as market powers of generation firms and transmission network operator, uncertainties of the future market, and interactions between the generation and transmission sectors. Results deduced from the developed models include (a) regulated transmission network operator will not reserve transmission capacity to gain extra profits; instead, it will make capacity expansion decisions to support the competition in the generation sector; (b) generation firms will provide more power supplies when there is more demand; (c) in the presence of future uncertainties, the generation firms will add more generation capacity if the demand in the future power market is expected to be higher; and (d) the transmission capacity invested by the transmission network operator depends on the characteristic of the power market and the topology of the transmission network. Also, the second model, which considers interactions between generation and transmission sectors, yields higher social welfare in the electric power market, than the third model where generation firms and transmission network operator make investment decisions separately.

A multi-pathway model for photosynthetic reaction center

NASA Astrophysics Data System (ADS)

Qin, M.; Shen, H. Z.; Yi, X. X.

2016-03-01

Charge separation occurs in a pair of tightly coupled chlorophylls at the heart of photosynthetic reaction centers of both plants and bacteria. Recently it has been shown that quantum coherence can, in principle, enhance the efficiency of a solar cell, working like a quantum heat engine. Here, we propose a biological quantum heat engine (BQHE) motivated by Photosystem II reaction center (PSII RC) to describe the charge separation. Our model mainly considers two charge-separation pathways which is more than that typically considered in the published literature. We explore how these cross-couplings increase the current and power of the charge separation and discuss the effects of multiple pathways in terms of current and power. The robustness of the BQHE against the charge recombination in natural PSII RC and dephasing induced by environments is also explored, and extension from two pathways to multiple pathways is made. These results suggest that noise-induced quantum coherence helps to suppress the influence of acceptor-to-donor charge recombination, and besides, nature-mimicking architectures with engineered multiple pathways for charge separations might be better for artificial solar energy devices considering the influence of environments.

Three-dimensional numerical investigation of the separation process in a vortex tube at different operating conditions

NASA Astrophysics Data System (ADS)

Rafiee, Seyed Ehsan; Sadeghiazad, M. M.

2016-06-01

Air separators provide safe, clean, and appropriate air flow to engines and are widely used in vehicles with large engines such as ships and submarines. In this operational study, the separation process inside a Ranque-Hilsch vortex tube cleaning (cooling) system is investigated to analyze the impact of the operating gas type on the vortex tube performance; the operating gases used are air, nitrogen, oxygen, carbon dioxide and nitrogen dioxide. The computational fluid dynamic model used is equipped with a three-dimensional structure, and the steady-state condition is applied during computations. The standard k-ɛ turbulence model is employed to resolve nonlinear flow equations, and various key parameters, such as hot and cold exhaust thermal drops, and power separation rates, are described numerically. The results show that nitrogen dioxide creates the greatest separation power out of all gases tested, and the numerical results are validated by good agreement with available experimental data. In addition, a comparison is made between the use of two different boundary conditions, the pressure-far-field and the pressure-outlet, when analyzing complex turbulent flows inside the air separators. Results present a comprehensive and practical solution for use in future numerical studies.

A comparison of two types of velocity models for the lunar crust: Smooth continuous and stepwise layered

NASA Technical Reports Server (NTRS)

Gangi, A. F.

1978-01-01

The data from the Apollo-14 and Apollo-16 Active Seismic Experiments were reanalyzed and show that a power-law velocity variation with depth is consistent with both the traveltimes and amplitudes of the first arrivals for source-to-geophone separations up to 32m. The data were improved by removing spurious glithches, flickering and stacking. While this improved the signal-to-noise ratios, it was not possible to measure the arrivals beyond 32m. The physical evidence that the shallow lunar regolith is made up of fine particles adds weight to the 1/6-power velocity model. The 1/6-power law predicts the traveltime t(x), varies with separation, x, as t(x) = t sub 0 (x/x sub 0) to the 5/6 power and, using a first-order theory, the amplitude, A(x), varies as A(x) = A sub 0 (x/x sub 0) to the (13-m)/12, M 1; the layer-velocity model predicts t(x) = t sub 0 (x/xsub 0) and A(x) = A sub 0 (x/x sub 0) to the 2nd power.

A mathematical model of the maximum power density attainable in an alkaline hydrogen/oxygen fuel cell

NASA Technical Reports Server (NTRS)

Kimble, Michael C.; White, Ralph E.

1991-01-01

A mathematical model of a hydrogen/oxygen alkaline fuel cell is presented that can be used to predict the polarization behavior under various power loads. The major limitations to achieving high power densities are indicated and methods to increase the maximum attainable power density are suggested. The alkaline fuel cell model describes the phenomena occurring in the solid, liquid, and gaseous phases of the anode, separator, and cathode regions based on porous electrode theory applied to three phases. Fundamental equations of chemical engineering that describe conservation of mass and charge, species transport, and kinetic phenomena are used to develop the model by treating all phases as a homogeneous continuum.

A theoretical study on hot charge-transfer states and dimensional effects of organic photocells based on an ideal diode model.

PubMed

Shimazaki, Tomomi; Nakajima, Takahito

2017-05-21

This paper discusses an ideal diode model with hot charge-transfer (CT) states to analyze the power conversion efficiency of an organic photocell. A free carrier generation mechanism via sunlight in an organic photocell consists of four microscopic processes: photon absorption, exciton dissociation, CT, and charge separation. The hot CT state effect has been actively investigated to understand the charge separation process. We previously reported a theoretical method to calculate the efficiency of the charge separation process via a hot CT state (T. Shimazaki et al., Phys. Chem. Chem. Phys., 2015, 17, 12538 and J. Chem. Phys., 2016, 144, 234906). In this paper, we integrate the simulation method into the ideal photocell diode model and calculate several properties such as short circuit current, open circuit voltage, and power conversion efficiency. Our results highlight that utilizing the dimensional (entropy) effect together with the hot CT state can play an essential role in developing more efficient organic photocell devices.

Separating Turbofan Engine Noise Sources Using Auto and Cross Spectra from Four Microphones

NASA Technical Reports Server (NTRS)

Miles, Jeffrey Hilton

2008-01-01

The study of core noise from turbofan engines has become more important as noise from other sources such as the fan and jet were reduced. A multiple-microphone and acoustic-source modeling method to separate correlated and uncorrelated sources is discussed. The auto- and cross spectra in the frequency range below 1000 Hz are fitted with a noise propagation model based on a source couplet consisting of a single incoherent monopole source with a single coherent monopole source or a source triplet consisting of a single incoherent monopole source with two coherent monopole point sources. Examples are presented using data from a Pratt& Whitney PW4098 turbofan engine. The method separates the low-frequency jet noise from the core noise at the nozzle exit. It is shown that at low power settings, the core noise is a major contributor to the noise. Even at higher power settings, it can be more important than jet noise. However, at low frequencies, uncorrelated broadband noise and jet noise become the important factors as the engine power setting is increased.

Environmental Enforcement of Federal Agencies: A Struggle for Power under the ’New Federalism’

DTIC Science & Technology

1990-01-01

Separation of Powers Dillemma ............ . 55 III. Establishment of Goals...federal power. Currently that countervailing federal 54 power does not exist because of the restraints imposed on EPA. 16 d. Separation of Powers Dilemma...structure and implies a necessary separation of powers . In Federalist 48 Madison discussed the connections necessary to maintain a proper separation of powers :

The Influence of Drift Gas Composition on the Separation Mechanism in Traveling Wave Ion Mobility Spectrometry: Insight from Electrodynamic Simulations

PubMed Central

May, Jody C.; McLean, John A.

2013-01-01

The influence of three different drift gases (helium, nitrogen, and argon) on the separation mechanism in traveling wave ion mobility spectrometry is explored through ion trajectory simulations which include considerations for ion diffusion based on kinetic theory and the electrodynamic traveling wave potential. The model developed for this work is an accurate depiction of a second-generation commercial traveling wave instrument. Three ion systems (cocaine, MDMA, and amphetamine) whose reduced mobility values have previously been measured in different drift gases are represented in the simulation model. The simulation results presented here provide a fundamental understanding of the separation mechanism in traveling wave, which is characterized by three regions of ion motion: (1) ions surfing on a single wave, (2) ions exhibiting intermittent roll-over onto subsequent waves, and (3) ions experiencing a steady state roll-over which repeats every few wave cycles. These regions of ion motion are accessed through changes in the gas pressure, wave amplitude, and wave velocity. Resolving power values extracted from simulated arrival times suggest that momentum transfer in helium gas is generally insufficient to access regions (2) and (3) where ion mobility separations occur. Ion mobility separations by traveling wave are predicted to be effectual for both nitrogen and argon, with slightly lower resolving power values observed for argon as a result of band-broadening due to collisional scattering. For the simulation conditions studied here, the resolving power in traveling wave plateaus between regions (2) and (3), with further increases in wave velocity contributing only minor improvements in separations. PMID:23888124

The Influence of Drift Gas Composition on the Separation Mechanism in Traveling Wave Ion Mobility Spectrometry: Insight from Electrodynamic Simulations.

PubMed

May, Jody C; McLean, John A

2003-06-01

The influence of three different drift gases (helium, nitrogen, and argon) on the separation mechanism in traveling wave ion mobility spectrometry is explored through ion trajectory simulations which include considerations for ion diffusion based on kinetic theory and the electrodynamic traveling wave potential. The model developed for this work is an accurate depiction of a second-generation commercial traveling wave instrument. Three ion systems (cocaine, MDMA, and amphetamine) whose reduced mobility values have previously been measured in different drift gases are represented in the simulation model. The simulation results presented here provide a fundamental understanding of the separation mechanism in traveling wave, which is characterized by three regions of ion motion: (1) ions surfing on a single wave, (2) ions exhibiting intermittent roll-over onto subsequent waves, and (3) ions experiencing a steady state roll-over which repeats every few wave cycles. These regions of ion motion are accessed through changes in the gas pressure, wave amplitude, and wave velocity. Resolving power values extracted from simulated arrival times suggest that momentum transfer in helium gas is generally insufficient to access regions (2) and (3) where ion mobility separations occur. Ion mobility separations by traveling wave are predicted to be effectual for both nitrogen and argon, with slightly lower resolving power values observed for argon as a result of band-broadening due to collisional scattering. For the simulation conditions studied here, the resolving power in traveling wave plateaus between regions (2) and (3), with further increases in wave velocity contributing only minor improvements in separations.

Stochastic Modelling of Wireless Energy Transfer

NASA Technical Reports Server (NTRS)

Veilleux, Shaun; Almaghasilah, Ahmed; Abedi, Ali; Wilkerson, DeLisa

2017-01-01

This study investigates the efficiency of a new method of powering remote sensors by the means of wireless energy transfer. The increased use of sensors for data collection comes with the inherent cost of supplying power from sources such as power cables or batteries. Wireless energy transfer technology eliminates the need for power cables or periodic battery replacement. The time and cost of setting up or expanding a sensor network will be reduced while allowing sensors to be placed in areas where running power cables or battery replacement is not feasible. This paper models wireless channels for power and data separately. Smart scheduling for the data channel is proposed to avoid transmitting data on a noisy channel where the probability of data loss is high to improve power efficiency. Analytical models have been developed and verified using simulations.

Modeling of turbulent separated flows for aerodynamic applications

NASA Technical Reports Server (NTRS)

Marvin, J. G.

1983-01-01

Steady, high speed, compressible separated flows modeled through numerical simulations resulting from solutions of the mass-averaged Navier-Stokes equations are reviewed. Emphasis is placed on benchmark flows that represent simplified (but realistic) aerodynamic phenomena. These include impinging shock waves, compression corners, glancing shock waves, trailing edge regions, and supersonic high angle of attack flows. A critical assessment of modeling capabilities is provided by comparing the numerical simulations with experiment. The importance of combining experiment, numerical algorithm, grid, and turbulence model to effectively develop this potentially powerful simulation technique is stressed.

Game-theoretic approach to joint transmitter adaptation and power control in wireless systems.

PubMed

Popescu, Dimitrie C; Rawat, Danda B; Popescu, Otilia; Saquib, Mohamad

2010-06-01

Game theory has emerged as a new mathematical tool in the analysis and design of wireless communication systems, being particularly useful in studying the interactions among adaptive transmitters that attempt to achieve specific objectives without cooperation. In this paper, we present a game-theoretic approach to the problem of joint transmitter adaptation and power control in wireless systems, where users' transmissions are subject to quality-of-service requirements specified in terms of target signal-to-interference-plus-noise ratios (SINRs) and nonideal vector channels between transmitters and receivers are explicitly considered. Our approach is based on application of separable games, which are a specific class of noncooperative games where the players' cost is a separable function of their strategic choices. We formally state a joint codeword and power adaptation game, which is separable, and we study its properties in terms of its subgames, namely, the codeword adaptation subgame and the power adaptation subgame. We investigate the necessary conditions for an optimal Nash equilibrium and show that this corresponds to an ensemble of user codewords and powers, which maximizes the sum capacity of the corresponding multiaccess vector channel model, and for which the specified target SINRs are achieved with minimum transmitted power.

Membrane-based osmotic heat engine with organic solvent for enhanced power generation from low-grade heat.

PubMed

Shaulsky, Evyatar; Boo, Chanhee; Lin, Shihong; Elimelech, Menachem

2015-05-05

We present a hybrid osmotic heat engine (OHE) system that uses draw solutions with an organic solvent for enhanced thermal separation efficiency. The hybrid OHE system produces sustainable energy by combining pressure-retarded osmosis (PRO) as a power generation stage and membrane distillation (MD) utilizing low-grade heat as a separation stage. While previous OHE systems employed aqueous electrolyte draw solutions, using methanol as a solvent is advantageous because methanol is highly volatile and has a lower heat capacity and enthalpy of vaporization than water. Hence, the thermal separation efficiency of a draw solution with methanol would be higher than that of an aqueous draw solution. In this study, we evaluated the performance of LiCl-methanol as a potential draw solution for a PRO-MD hybrid OHE system. The membrane transport properties as well as performance with LiCl-methanol draw solution were evaluated using thin-film composite (TFC) PRO membranes and compared to the results obtained with a LiCl-water draw solution. Experimental PRO methanol flux and maximum projected power density of 47.1 L m(-2) h(-1) and 72.1 W m(-2), respectively, were achieved with a 3 M LiCl-methanol draw solution. The overall efficiency of the hybrid OHE system was modeled by coupling the mass and energy flows between the thermal separation (MD) and power generation (PRO) stages under conditions with and without heat recovery. The modeling results demonstrate higher OHE energy efficiency with the LiCl-methanol draw solution compared to that with the LiCl-water draw solution under practical operating conditions (i.e., heat recovery<90%). We discuss the implications of the results for converting low-grade heat to power.

Membrane-Based Osmotic Heat Engine with Organic Solvent for Enhanced Power Generation from Low-Grade Heat

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

Shaulsky, E; Boo, C; Lin, SH

We present a hybrid osmotic heat engine (OHE) system that uses draw solutions with an organic solvent for enhanced thermal separation efficiency. The hybrid OHE system produces sustainable energy by combining pressure-retarded osmosis (PRO) as a power generation stage and membrane distillation (MD) utilizing low-grade heat as a separation stage. While previous OHE systems employed aqueous electrolyte draw solutions, using methanol as a solvent is advantageous because methanol is highly volatile and has a lower heat capacity and enthalpy of vaporization than water. Hence, the thermal separation efficiency of a draw solution with methanol would be higher than that ofmore » an aqueous draw solution. In this study, we evaluated the performance of LiCl-methanol as a potential draw solution for a PRO-MD hybrid OHE system. The membrane transport properties as well as performance with LiCl methanol draw solution were evaluated using thin-film composite (TFC) PRO membranes and compared to the results obtained with a LiCl water draw solution. Experimental PRO methanol flux and maximum projected power density of 47.1 L m(-2) h(-1) and 72.1 W m(-2), respectively, were achieved with a 3 M LiCl-methanol draw solution. The overall efficiency of the hybrid OHE system was modeled by coupling the mass and energy flows between the thermal separation (MD) and power generation (PRO) stages under conditions with and without heat recovery. The modeling results demonstrate higher ORE energy efficiency with the LiCl methanol draw solution compared to that with the LiCl water draw solution under practical operating conditions (i.e., heat recovery <90%). We discuss the implications of the results for converting low-grade heat to power.« less

Modeling and Optimization of Coordinative Operation of Hydro-wind-photovoltaic Considering Power Generation and Output Fluctuation

NASA Astrophysics Data System (ADS)

Wang, Xianxun; Mei, Yadong

2017-04-01

Coordinative operation of hydro-wind-photovoltaic is the solution of mitigating the conflict of power generation and output fluctuation of new energy and conquering the bottleneck of new energy development. Due to the deficiencies of characterizing output fluctuation, depicting grid construction and disposal of power abandon, the research of coordinative mechanism is influenced. In this paper, the multi-object and multi-hierarchy model of coordinative operation of hydro-wind-photovoltaic is built with the aim of maximizing power generation and minimizing output fluctuation and the constraints of topotaxy of power grid and balanced disposal of power abandon. In the case study, the comparison of uncoordinative and coordinative operation is carried out with the perspectives of power generation, power abandon and output fluctuation. By comparison from power generation, power abandon and output fluctuation between separate operation and coordinative operation of multi-power, the coordinative mechanism is studied. Compared with running solely, coordinative operation of hydro-wind-photovoltaic can gain the compensation benefits. Peak-alternation operation reduces the power abandon significantly and maximizes resource utilization effectively by compensating regulation of hydropower. The Pareto frontier of power generation and output fluctuation is obtained through multiple-objective optimization. It clarifies the relationship of mutual influence between these two objects. When coordinative operation is taken, output fluctuation can be markedly reduced at the cost of a slight decline of power generation. The power abandon also drops sharply compared with operating separately. Applying multi-objective optimization method to optimize the coordinate operation, Pareto optimal solution set of power generation and output fluctuation is achieved.

Microwave transmission system for space power

NASA Technical Reports Server (NTRS)

Dickinson, R. M.

1976-01-01

A small total system model and a large subsystem element similar to those that could be eventually used for wireless power transmission experiments in space have been successfully demonstrated by NASA. The short range, relatively low-power laboratory system achieved a dc-to-dc transmission efficiency of 54%. A separate high-power-level receiving subsystem, tested over a 1.54-km range at Goldstone, California, has achieved the transportation of over 30 kW of dc output power. Both tests used 12-cm wavelength microwaves.

Transient Control of Synchronous Machine Active and Reactive Power in Micro-grid Power Systems

NASA Astrophysics Data System (ADS)

Weber, Luke G.

There are two main topics associated with this dissertation. The first is to investigate phase-to-neutral fault current magnitude occurring in generators with multiple zero-sequence current sources. The second is to design, model, and tune a linear control system for operating a micro-grid in the event of a separation from the electric power system. In the former case, detailed generator, AC8B excitation system, and four-wire electric power system models are constructed. Where available, manufacturers data is used to validate the generator and exciter models. A gain-delay with frequency droop control is used to model an internal combustion engine and governor. The four wire system is connected through a transformer impedance to an infinite bus. Phase-to-neutral faults are imposed on the system, and fault magnitudes analyzed against three-phase faults to gauge their severity. In the latter case, a balanced three-phase system is assumed. The model structure from the former case - but using data for a different generator - is incorporated with a model for an energy storage device and a net load model to form a micro-grid. The primary control model for the energy storage device has a high level of detail, as does the energy storage device plant model in describing the LC filter and transformer. A gain-delay battery and inverter model is used at the front end. The net load model is intended to be the difference between renewable energy sources and load within a micro-grid system that has separated from the grid. Given the variability of both renewable generation and load, frequency and voltage stability are not guaranteed. This work is an attempt to model components of a proposed micro-grid system at the University of Wisconsin Milwaukee, and design, model, and tune a linear control system for operation in the event of a separation from the electric power system. The control module is responsible for management of frequency and active power, and voltage and reactive power. The scope of this work is to • develop a mathematical model for a salient pole, 2 damper winding synchronous generator with d axis saturation suitable for transient analysis, • develop a mathematical model for a voltage regulator and excitation system using the IEEE AC8B voltage regulator and excitation system template, • develop mathematical models for an energy storage primary control system, LC filter and transformer suitable for transient analysis, • combine the generator and energy storage models in a micro-grid context, • develop mathematical models for electric system components in the stationary abc frame and rotating dq reference frame, • develop a secondary control network for dispatch of micro-grid assets, • establish micro-grid limits of stable operation for step changes in load and power commands based on simulations of model data assuming net load on the micro-grid, and • use generator and electric system models to assess the generator current magnitude during phase-to-ground faults.

AlGaAs-GaAs quantum-well lasers for direct solar photopumping

NASA Technical Reports Server (NTRS)

Unnikrishnan, Sreenath; Anderson, Neal G.

1991-01-01

The paper theoretically examines the solar power requirements for low-threshold AlGaAs-GaAs quantum-well lasers directly photopumped by focused sunlight. A model of separate-confinement quantum-well-heterostructure (SCQWH) lasers was developed, which explicitly treats absorption and transport phenomena relevant to solar pumping. The model was used to identify separate-confinement single-quantum-well laser structures which should operate at photoexcitation intensities of less than 10,000 suns.

Congressional Oversight of Judges and Justices

DTIC Science & Technology

2005-05-31

separation of powers . Further...Committee was an unconstitutional interference with judicial independence and a violation of separation of powers .86 The doctrine of separation of powers is...between two approaches to cases raising separation - of - powers claims, using a strict approach in some cases and a less rigid balancing approach in

A linear, separable two-parameter model for dual energy CT imaging of proton stopping power computation

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

Han, Dong, E-mail: radon.han@gmail.com; Williamson, Jeffrey F.; Siebers, Jeffrey V.

2016-01-15

Purpose: To evaluate the accuracy and robustness of a simple, linear, separable, two-parameter model (basis vector model, BVM) in mapping proton stopping powers via dual energy computed tomography (DECT) imaging. Methods: The BVM assumes that photon cross sections (attenuation coefficients) of unknown materials are linear combinations of the corresponding radiological quantities of dissimilar basis substances (i.e., polystyrene, CaCl{sub 2} aqueous solution, and water). The authors have extended this approach to the estimation of electron density and mean excitation energy, which are required parameters for computing proton stopping powers via the Bethe–Bloch equation. The authors compared the stopping power estimation accuracymore » of the BVM with that of a nonlinear, nonseparable photon cross section Torikoshi parametric fit model (VCU tPFM) as implemented by the authors and by Yang et al. [“Theoretical variance analysis of single- and dual-energy computed tomography methods for calculating proton stopping power ratios of biological tissues,” Phys. Med. Biol. 55, 1343–1362 (2010)]. Using an idealized monoenergetic DECT imaging model, proton ranges estimated by the BVM, VCU tPFM, and Yang tPFM were compared to International Commission on Radiation Units and Measurements (ICRU) published reference values. The robustness of the stopping power prediction accuracy of tissue composition variations was assessed for both of the BVM and VCU tPFM. The sensitivity of accuracy to CT image uncertainty was also evaluated. Results: Based on the authors’ idealized, error-free DECT imaging model, the root-mean-square error of BVM proton stopping power estimation for 175 MeV protons relative to ICRU reference values for 34 ICRU standard tissues is 0.20%, compared to 0.23% and 0.68% for the Yang and VCU tPFM models, respectively. The range estimation errors were less than 1 mm for the BVM and Yang tPFM models, respectively. The BVM estimation accuracy is not dependent on tissue type and proton energy range. The BVM is slightly more vulnerable to CT image intensity uncertainties than the tPFM models. Both the BVM and tPFM prediction accuracies were robust to uncertainties of tissue composition and independent of the choice of reference values. This reported accuracy does not include the impacts of I-value uncertainties and imaging artifacts and may not be achievable on current clinical CT scanners. Conclusions: The proton stopping power estimation accuracy of the proposed linear, separable BVM model is comparable to or better than that of the nonseparable tPFM models proposed by other groups. In contrast to the tPFM, the BVM does not require an iterative solving for effective atomic number and electron density at every voxel; this improves the computational efficiency of DECT imaging when iterative, model-based image reconstruction algorithms are used to minimize noise and systematic imaging artifacts of CT images.« less

The War Powers Resolution: Intent Implementation and Impact

DTIC Science & Technology

1993-04-01

separation of powers , the authority as Commander-in-Chief is also specifically delegated to the President. The clear intent of the founders of our nation was... separation of powers spelled out - in sufficient detail they thought -- so that there would be little or no ambiguity over who exercised what powers...OF CONFLICT SEPARATION OF POWERS As discussed in the opening paragraphs of this paper, the founding fathers intentionally delegated 20 separate powers

Plasma separation process. Betacell (BCELL) code, user's manual

NASA Astrophysics Data System (ADS)

Taherzadeh, M.

1987-11-01

The emergence of clearly defined applications for (small or large) amounts of long-life and reliable power sources has given the design and production of betavoltaic systems a new life. Moreover, because of the availability of the Plasma Separation Program, (PSP) at TRW, it is now possible to separate the most desirable radioisotopes for betacell power generating devices. A computer code, named BCELL, has been developed to model the betavoltaic concept by utilizing the available up-to-date source/cell parameters. In this program, attempts have been made to determine the betacell energy device maximum efficiency, degradation due to the emitting source radiation and source/cell lifetime power reduction processes. Additionally, comparison is made between the Schottky and PN junction devices for betacell battery design purposes. Certain computer code runs have been made to determine the JV distribution function and the upper limit of the betacell generated power for specified energy sources. A Ni beta emitting radioisotope was used for the energy source and certain semiconductors were used for the converter subsystem of the betacell system. Some results for a Promethium source are also given here for comparison.

Fourier band-power E/B-mode estimators for cosmic shear

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

Becker, Matthew R.; Rozo, Eduardo

We introduce new Fourier band-power estimators for cosmic shear data analysis and E/B-mode separation. We consider both the case where one performs E/B-mode separation and the case where one does not. The resulting estimators have several nice properties which make them ideal for cosmic shear data analysis. First, they can be written as linear combinations of the binned cosmic shear correlation functions. Secondly, they account for the survey window function in real-space. Thirdly, they are unbiased by shape noise since they do not use correlation function data at zero separation. Fourthly, the band-power window functions in Fourier space are compactmore » and largely non-oscillatory. Fifthly, they can be used to construct band-power estimators with very efficient data compression properties. In particular, we find that all of the information on the parameters Ωm, σ8 and ns in the shear correlation functions in the range of ~10–400 arcmin for single tomographic bin can be compressed into only three band-power estimates. Finally, we can achieve these rates of data compression while excluding small-scale information where the modelling of the shear correlation functions and power spectra is very difficult. Given these desirable properties, these estimators will be very useful for cosmic shear data analysis.« less

WE-D-BRF-05: Quantitative Dual-Energy CT Imaging for Proton Stopping Power Computation

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

Han, D; Williamson, J; Siebers, J

2014-06-15

Purpose: To extend the two-parameter separable basis-vector model (BVM) to estimation of proton stopping power from dual-energy CT (DECT) imaging. Methods: BVM assumes that the photon cross sections of any unknown material can be represented as a linear combination of the corresponding quantities for two bracketing basis materials. We show that both the electron density (ρe) and mean excitation energy (Iex) can be modeled by BVM, enabling stopping power to be estimated from the Bethe-Bloch equation. We have implemented an idealized post-processing dual energy imaging (pDECT) simulation consisting of monogenetic 45 keV and 80 keV scanning beams with polystyrene-water andmore » water-CaCl2 solution basis pairs for soft tissues and bony tissues, respectively. The coefficients of 24 standard ICRU tissue compositions were estimated by pDECT. The corresponding ρe, Iex, and stopping power tables were evaluated via BVM and compared to tabulated ICRU 44 reference values. Results: BVM-based pDECT was found to estimate ρe and Iex with average and maximum errors of 0.5% and 2%, respectively, for the 24 tissues. Proton stopping power values at 175 MeV, show average/maximum errors of 0.8%/1.4%. For adipose, muscle and bone, these errors result range prediction accuracies less than 1%. Conclusion: A new two-parameter separable DECT model (BVM) for estimating proton stopping power was developed. Compared to competing parametric fit DECT models, BVM has the comparable prediction accuracy without necessitating iterative solution of nonlinear equations or a sample-dependent empirical relationship between effective atomic number and Iex. Based on the proton BVM, an efficient iterative statistical DECT reconstruction model is under development.« less

Simple turbulence models and their application to boundary layer separation

NASA Technical Reports Server (NTRS)

Wadcock, A. J.

1980-01-01

Measurements in the boundary layer and wake of a stalled airfoil are presented in two coordinate systems, one aligned with the airfoil chord, the other being conventional boundary layer coordinates. The NACA 4412 airfoil is studied at a single angle of attack corresponding to maximum lift, the Reynolds number based on chord being 1.5 x 10 to the 6th power. Turbulent boundary layer separation occurred at the 85 percent chord position. The two-dimensionality of the flow was documented and the momentum integral equation studied to illustrate the importance of turbulence contributions as separation is approached. The assumptions of simple eddy-viscosity and mixing-length turbulence models are checked directly against experiment. Curvature effects are found to be important as separation is approached.

An investigation of the unsteady flow associated with plume induced flow separation

NASA Technical Reports Server (NTRS)

Boggess, A. L., Jr.

1972-01-01

A wind tunnel study of the basic nature of plume induced flow separation is reported with emphasis on the unsteady aspects of the flow. Testing was conducted in a 6 inch by 6 inch blow-down supersonic wind tunnel. A cone-cylinder model with a pluming jet was used as the test model. Tests were conducted with a systematic variation in Mach number and plume pressure. Results of the tests are presented in the form of root-mean-squared surface pressure levels, power spectral densities, photographs of the flow field from which shock angles and separation lengths were taken, and time-averaged surface pressure profiles.

A Hierarchical Modeling for Reactive Power Optimization With Joint Transmission and Distribution Networks by Curve Fitting

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

Ding, Tao; Li, Cheng; Huang, Can

Here, in order to solve the reactive power optimization with joint transmission and distribution networks, a hierarchical modeling method is proposed in this paper. It allows the reactive power optimization of transmission and distribution networks to be performed separately, leading to a master–slave structure and improves traditional centralized modeling methods by alleviating the big data problem in a control center. Specifically, the transmission-distribution-network coordination issue of the hierarchical modeling method is investigated. First, a curve-fitting approach is developed to provide a cost function of the slave model for the master model, which reflects the impacts of each slave model. Second,more » the transmission and distribution networks are decoupled at feeder buses, and all the distribution networks are coordinated by the master reactive power optimization model to achieve the global optimality. Finally, numerical results on two test systems verify the effectiveness of the proposed hierarchical modeling and curve-fitting methods.« less

A Hierarchical Modeling for Reactive Power Optimization With Joint Transmission and Distribution Networks by Curve Fitting

DOE PAGES

Ding, Tao; Li, Cheng; Huang, Can; ...

2017-01-09

Here, in order to solve the reactive power optimization with joint transmission and distribution networks, a hierarchical modeling method is proposed in this paper. It allows the reactive power optimization of transmission and distribution networks to be performed separately, leading to a master–slave structure and improves traditional centralized modeling methods by alleviating the big data problem in a control center. Specifically, the transmission-distribution-network coordination issue of the hierarchical modeling method is investigated. First, a curve-fitting approach is developed to provide a cost function of the slave model for the master model, which reflects the impacts of each slave model. Second,more » the transmission and distribution networks are decoupled at feeder buses, and all the distribution networks are coordinated by the master reactive power optimization model to achieve the global optimality. Finally, numerical results on two test systems verify the effectiveness of the proposed hierarchical modeling and curve-fitting methods.« less

Stirling System Modeling for Space Nuclear Power Systems

NASA Technical Reports Server (NTRS)

Lewandowski, Edward J.; Johnson, Paul K.

2008-01-01

A dynamic model of a high-power Stirling convertor has been developed for space nuclear power systems modeling. The model is based on the Component Test Power Convertor (CTPC), a 12.5-kWe free-piston Stirling convertor. The model includes the fluid heat source, the Stirling convertor, output power, and heat rejection. The Stirling convertor model includes the Stirling cycle thermodynamics, heat flow, mechanical mass-spring damper systems, and the linear alternator. The model was validated against test data. Both nonlinear and linear versions of the model were developed. The linear version algebraically couples two separate linear dynamic models; one model of the Stirling cycle and one model of the thermal system, through the pressure factors. Future possible uses of the Stirling system dynamic model are discussed. A pair of commercially available 1-kWe Stirling convertors is being purchased by NASA Glenn Research Center. The specifications of those convertors may eventually be incorporated into the dynamic model and analysis compared to the convertor test data. Subsequent potential testing could include integrating the convertors into a pumped liquid metal hot-end interface. This test would provide more data for comparison to the dynamic model analysis.

Operation Iraqi Freedom - An Unjust War

DTIC Science & Technology

2004-02-09

the President. Clearly there is a separation of powers when it comes to the use of the military. This country’s history is founded on the separation ...country this separation of powers has been tested. It is necessary that this government with its separate branches of authority, struggles with, and... of powers , to prevent any one branch of the government from wielding too much power. The founding fathers feared too much power in one branch of the

Enemy Combatant Detainees: Habeas Corpus Challenges in Federal Court

DTIC Science & Technology

2009-04-07

Authority over Federal Courts ......................................................................... 50 Separation of Powers Issues...executive and legislative branches.193 The Court stated that the separation - of - powers doctrine and the history shaping the design of the Suspension Clause...way that violates precepts of separation of powers . The doctrine of separation of powers is not found in the text of the Constitution, but has been

A Copula-Based Conditional Probabilistic Forecast Model for Wind Power Ramps

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

Hodge, Brian S; Krishnan, Venkat K; Zhang, Jie

Efficient management of wind ramping characteristics can significantly reduce wind integration costs for balancing authorities. By considering the stochastic dependence of wind power ramp (WPR) features, this paper develops a conditional probabilistic wind power ramp forecast (cp-WPRF) model based on Copula theory. The WPRs dataset is constructed by extracting ramps from a large dataset of historical wind power. Each WPR feature (e.g., rate, magnitude, duration, and start-time) is separately forecasted by considering the coupling effects among different ramp features. To accurately model the marginal distributions with a copula, a Gaussian mixture model (GMM) is adopted to characterize the WPR uncertaintymore » and features. The Canonical Maximum Likelihood (CML) method is used to estimate parameters of the multivariable copula. The optimal copula model is chosen based on the Bayesian information criterion (BIC) from each copula family. Finally, the best conditions based cp-WPRF model is determined by predictive interval (PI) based evaluation metrics. Numerical simulations on publicly available wind power data show that the developed copula-based cp-WPRF model can predict WPRs with a high level of reliability and sharpness.« less

Dependence of optimal separative power of the “high-speed” Iguasu centrifuge on pressure of working gas

NASA Astrophysics Data System (ADS)

Bogovalov, S. V.; Borman, V. D.; Borisevich, V. D.; Davidenko, O. V.; Tronin, I. V.; Tronin, V. N.

2016-09-01

The results of optimization calculations of the separative power of the ’’high-speed” Iguasu gas centrifuge are presented. Iguasu gas centrifuge has the rotational speed of 1000 m/s, the rotor length of 1 m. The dependence of the optimal separative power on the pressure of the working gas on the rotor wall was obtained using the numerical simulations. It is shown, that maximum of the optimal separative power corresponds to the pressure of 1100 mmHg. Maximum value of separative power is 31.9 SWU.

Is stair climb power a clinically relevant measure of leg power impairments in at-risk older adults?

PubMed

Bean, Jonathan F; Kiely, Dan K; LaRose, Sharon; Alian, Joda; Frontera, Walter R

2007-05-01

To test the clinical relevance of the stair climb power test (SCPT) as a measure of leg power impairments in mobility-limited older adults. Cross-sectional analysis of baseline data from participants within a randomized controlled trial. Rehabilitation research gym. Community-dwelling older adults (N=138; mean age, 75.4 y) with mobility limitations as defined by the Short Physical Performance Battery (SPPB). Not applicable. Leg power measures included the SCPT and double leg press power measured at 40% (DLP40) and 70% (DLP70) of the 1 repetition maximum. Mobility performance tests included the SPPB and its 3 components: gait speed, chair stand time, and standing balance. Stair climb power per kilogram (SCP/kg) had correlations of moderate strength (r=.47, r=.52) with DLP40/kg and DLP70/kg, respectively. All 3 leg power measures correlated with each of the mobility performance measures with the exception of DLP40/kg (r=.11, P=.27) and DLP70/kg (r=.11, P=.18) with standing balance. Magnitudes of association, as described by the Pearson correlation coefficient, did not differ substantively among the separate power measures as they related to SPPB performance overall. Separate adjusted multivariate models evaluating the relationship between leg power and SPPB performance were all statistically significant and described equivalent amounts of the total variance (R(2)) in SPPB performance (SCP/kg, R(2)=.30; DLP40, R(2)=.32; DLP70, R(2)=.31). Analyses of the components of the SPPB show that the SCPT had stronger associations than the other leg power impairment measures with models predicting chair stand (SCP/kg, R(2)=.25; DLP40, R(2)=.12; DLP70, R(2)=.13), whereas both types of leg press power testing had stronger associations with models predicting gait speed (SCP/kg, R(2)=.16; DLP40, R(2)=.34; DLP70, R(2)=.34). Stair climb power was the only power measure that was a significant component of models predicting standing balance (SCP/kg R(2)=.20). The SCPT is a clinically relevant measure of leg power impairments. It is associated with more complex modes of testing leg power impairments and is meaningfully associated with mobility performance, making it suitable for clinical settings in which impairment-mobility relationships are of interest.

Plasma Separation Process: Betacell (BCELL) code: User's manual. [Bipolar barrier junction

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

Taherzadeh, M.

1987-11-13

The emergence of clearly defined applications for (small or large) amounts of long-life and reliable power sources has given the design and production of betavoltaic systems a new life. Moreover, because of the availability of the plasma separation program, (PSP) at TRW, it is now possible to separate the most desirable radioisotopes for betacell power generating devices. A computer code, named BCELL, has been developed to model the betavoltaic concept by utilizing the available up-to-date source/cell parameters. In this program, attempts have been made to determine the betacell energy device maximum efficiency, degradation due to the emitting source radiation andmore » source/cell lifetime power reduction processes. Additionally, comparison is made between the Schottky and PN junction devices for betacell battery design purposes. Certain computer code runs have been made to determine the JV distribution function and the upper limit of the betacell generated power for specified energy sources. A Ni beta emitting radioisotope was used for the energy source and certain semiconductors were used for the converter subsystem of the betacell system. Some results for a Promethium source are also given here for comparison. 16 refs.« less

Restrictive loads powered by separate or by common electrical sources

NASA Technical Reports Server (NTRS)

Appelbaum, J.

1989-01-01

In designing a multiple load electrical system, the designer may wish to compare the performance of two setups: a common electrical source powering all loads, or separate electrical sources powering individual loads. Three types of electrical sources: an ideal voltage source, an ideal current source, and solar cell source powering resistive loads were analyzed for their performances in separate and common source systems. A mathematical proof is given, for each case, indicating the merit of the separate or common source system. The main conclusions are: (1) identical resistive loads powered by ideal voltage sources perform the same in both system setups, (2) nonidentical resistive loads powered by ideal voltage sources perform the same in both system setups, (3) nonidentical resistive loads powered by ideal current sources have higher performance in separate source systems, and (4) nonidentical resistive loads powered by solar cells have higher performance in a common source system for a wide range of load resistances.

Spray-on polyvinyl alcohol separators and impact on power production in air-cathode microbial fuel cells with different solution conductivities.

PubMed

Hoskins, Daniel L; Zhang, Xiaoyuan; Hickner, Michael A; Logan, Bruce E

2014-11-01

Separators are used to protect cathodes from biofouling and to avoid electrode short-circuiting, but they can adversely affect microbial fuel cell (MFC) performance. A spray method was used to apply a polyvinyl alcohol (PVA) separator to the cathode. Power densities were unaffected by the PVA separator (339±29mW/m(2)), compared to a control lacking a separator in a low conductivity solution (1mS/cm) similar to wastewater. Power was reduced with separators in solutions typical of laboratory tests (7-13mS/cm), compared to separatorless controls. The PVA separator produced more power in a separator assembly (SEA) configuration (444±8mW/m(2)) in the 1mS/cm solution, but power was reduced if a PVA or wipe separator was used in higher conductivity solutions with either Pt or activated carbon catalysts. Spray and cast PVA separators performed similarly, but the spray method is preferred as it was easier to apply and use. Copyright © 2014 Elsevier Ltd. All rights reserved.

Polymer membranes as separators for supercapacitors

NASA Astrophysics Data System (ADS)

Szubzda, Bronisław; Szmaja, Aleksandra; Ozimek, Mariusz; Mazurkiewicz, Sławomir

2014-12-01

The purpose of the studies described was to examine the influence of low-energy plasma modification of polyamide and polypropylene polymer nonwoven fabrics on the usable properties of supercapacitors when using these fabrics as the separator material. To achieve this goal the following investigations were carried out: testing the time required for electrolyte saturation of separators and the conductivity of the electrolyte contained in the separator, as well as electrochemical examinations of supercapacitor models in which the modified fabric separators were used. The tests conducted fully confirm the usability of this modification for cleaning the surface and improving the wettability of separators by the electrolyte, which in turn results in a significant decrease of the internal resistance of the supercapacitor, thus increasing the usable power of the device.

A New Paradigm for Supergranulation Derived from Large-Distance Time-Distance Helioseismology: Pancakes

NASA Technical Reports Server (NTRS)

Duvall, Thomas L.; Hanasoge, Shravan M.

2012-01-01

With large separations (10-24 deg heliocentric), it has proven possible to cleanly separate the horizontal and vertical components of supergranular flow with time-distance helioseismology. These measurements require very broad filters in the k-$\\omega$ power spectrum as apparently supergranulation scatters waves over a large area of the power spectrum. By picking locations of supergranulation as peaks in the horizontal divergence signal derived from f-mode waves, it is possible to simultaneously obtain average properties of supergranules and a high signal/noise ratio by averaging over many cells. By comparing ray-theory forward modeling with HMI measurements, an average supergranule model with a peak upflow of 240 m/s at cell center at a depth of 2.3 Mm and a peak horizontal outflow of 700 m/s at a depth of 1.6 Mm. This upflow is a factor of 20 larger than the measured photospheric upflow. These results may not be consistent with earlier measurements using much shorter separations (<5 deg heliocentric). With a 30 Mm horizontal extent and a few Mm in depth, the cells might be characterized as thick pancakes.

A model relating radiated power and impurity concentrations during Ne, N and Ar injection in Tore Supra

NASA Astrophysics Data System (ADS)

Hogan, J.; Demichelis, C.; Monier-Garbet, P.; Guirlet, R.; Hess, W.; Schunke, B.

2000-10-01

A model combining the MIST (core symmetric) and BBQ (SOL asymmetric) codes is used to study the relation between impurity density and radiated power for representative cases from Tore Supra experiments on strong radiation regimes using the ergodic divertor. Transport predictions of external radiation are compared with observation to estimate the absolute impurity density. BBQ provides the incoming distribution of recycling impurity charge states for the radial transport calculation. The shots studied use the ergodic divertor and high ICRH power. Power is first applied and then the extrinsic impurity (Ne, N or Ar) is injected. Separate time dependent intrinsic (C and O) impurity transport calculations match radiation levels before and during the high power and impurity injection phases. Empirical diffusivities are sought to reproduce the UV (CV R, I lines), CVI Lya, OVIII Lya, Zeff, and horizontal bolometer data. The model has been used to calculate the relative radiative efficiency (radiated power / extrinsically contributed electron) for the sample database.

Contemporary Perspectives on the Constitution and Separation of Powers.

ERIC Educational Resources Information Center

American Bar Association, Chicago, IL. Special Committee on Youth Education for Citizenship.

A collection of essays designed to provide educators and other interested individuals with contemporary perspectives on the U.S. Constitution and separation of powers is presented. Separation of powers refers to one of the enduring principles of the U.S. constitutional system of government, in which governmental powers are subject to a division of…

Near-Field Acoustic Power Level Analysis of F31/A31 Open Rotor Model at Simulated Cruise Conditions, Technical Report II

NASA Technical Reports Server (NTRS)

Sree, Dave

2015-01-01

Near-field acoustic power level analysis of F31A31 open rotor model has been performed to determine its noise characteristics at simulated cruise flight conditions. The non-proprietary parts of the test data obtained from experiments in the 8x6 supersonic wind tunnel were provided by NASA-Glenn Research Center. The tone and broadband components of total noise have been separated from raw test data by using a new data analysis tool. Results in terms of sound pressure levels, acoustic power levels, and their variations with rotor speed, freestream Mach number, and input shaft power, with different blade-pitch setting angles at simulated cruise flight conditions, are presented and discussed. Empirical equations relating models acoustic power level and input shaft power have been developed. The near-field acoustic efficiency of the model at simulated cruise conditions is also determined. It is hoped that the results presented in this work will serve as a database for comparison and improvement of other open rotor blade designs and also for validating open rotor noise prediction codes.

Fluid dynamic mechanisms and interactions within separated flows and their effects on missile aerodynamics

NASA Astrophysics Data System (ADS)

Addy, A. L.; Chow, W. L.; Korst, H. H.; White, R. A.

1983-05-01

Significant data and detailed results of a joint research effort investigating the fluid dynamic mechanisms and interactions within separated flows are presented. The results were obtained through analytical, experimental, and computational investigations of base flow related configurations. The research objectives focus on understanding the component mechanisms and interactions which establish and maintain separated flow regions. Flow models and theoretical analyses were developed to describe the base flowfield. The research approach has been to conduct extensive small-scale experiments on base flow configurations and to analyze these flows by component models and finite-difference techniques. The modeling of base flows of missiles (both powered and unpowered) for transonic and supersonic freestreams has been successful by component models. Research on plume effects and plume modeling indicated the need to match initial plume slope and plume surface curvature for valid wind tunnel simulation of an actual rocket plume. The assembly and development of a state-of-the-art laser Doppler velocimeter (LDV) system for experiments with two-dimensional small-scale models has been completed and detailed velocity and turbulence measurements are underway. The LDV experiments include the entire range of base flowfield mechanisms - shear layer development, recompression/reattachment, shock-induced separation, and plume-induced separation.

The use of imprecise processing to improve accuracy in weather & climate prediction

NASA Astrophysics Data System (ADS)

Düben, Peter D.; McNamara, Hugh; Palmer, T. N.

2014-08-01

The use of stochastic processing hardware and low precision arithmetic in atmospheric models is investigated. Stochastic processors allow hardware-induced faults in calculations, sacrificing bit-reproducibility and precision in exchange for improvements in performance and potentially accuracy of forecasts, due to a reduction in power consumption that could allow higher resolution. A similar trade-off is achieved using low precision arithmetic, with improvements in computation and communication speed and savings in storage and memory requirements. As high-performance computing becomes more massively parallel and power intensive, these two approaches may be important stepping stones in the pursuit of global cloud-resolving atmospheric modelling. The impact of both hardware induced faults and low precision arithmetic is tested using the Lorenz '96 model and the dynamical core of a global atmosphere model. In the Lorenz '96 model there is a natural scale separation; the spectral discretisation used in the dynamical core also allows large and small scale dynamics to be treated separately within the code. Such scale separation allows the impact of lower-accuracy arithmetic to be restricted to components close to the truncation scales and hence close to the necessarily inexact parametrised representations of unresolved processes. By contrast, the larger scales are calculated using high precision deterministic arithmetic. Hardware faults from stochastic processors are emulated using a bit-flip model with different fault rates. Our simulations show that both approaches to inexact calculations do not substantially affect the large scale behaviour, provided they are restricted to act only on smaller scales. By contrast, results from the Lorenz '96 simulations are superior when small scales are calculated on an emulated stochastic processor than when those small scales are parametrised. This suggests that inexact calculations at the small scale could reduce computation and power costs without adversely affecting the quality of the simulations. This would allow higher resolution models to be run at the same computational cost.

Joint Bayesian Component Separation and CMB Power Spectrum Estimation

NASA Technical Reports Server (NTRS)

Eriksen, H. K.; Jewell, J. B.; Dickinson, C.; Banday, A. J.; Gorski, K. M.; Lawrence, C. R.

2008-01-01

We describe and implement an exact, flexible, and computationally efficient algorithm for joint component separation and CMB power spectrum estimation, building on a Gibbs sampling framework. Two essential new features are (1) conditional sampling of foreground spectral parameters and (2) joint sampling of all amplitude-type degrees of freedom (e.g., CMB, foreground pixel amplitudes, and global template amplitudes) given spectral parameters. Given a parametric model of the foreground signals, we estimate efficiently and accurately the exact joint foreground- CMB posterior distribution and, therefore, all marginal distributions such as the CMB power spectrum or foreground spectral index posteriors. The main limitation of the current implementation is the requirement of identical beam responses at all frequencies, which restricts the analysis to the lowest resolution of a given experiment. We outline a future generalization to multiresolution observations. To verify the method, we analyze simple models and compare the results to analytical predictions. We then analyze a realistic simulation with properties similar to the 3 yr WMAP data, downgraded to a common resolution of 3 deg FWHM. The results from the actual 3 yr WMAP temperature analysis are presented in a companion Letter.

Numerical modeling and optimization of the Iguassu gas centrifuge

NASA Astrophysics Data System (ADS)

Bogovalov, S. V.; Borman, V. D.; Borisevich, V. D.; Tronin, V. N.; Tronin, I. V.

2017-07-01

The full procedure of the numerical calculation of the optimized parameters of the Iguassu gas centrifuge (GC) is under discussion. The procedure consists of a few steps. On the first step the problem of a hydrodynamical flow of the gas in the rotating rotor of the GC is solved numerically. On the second step the problem of diffusion of the binary mixture of isotopes is solved. The separation power of the gas centrifuge is calculated after that. On the last step the time consuming procedure of optimization of the GC is performed providing us the maximum of the separation power. The optimization is based on the BOBYQA method exploring the results of numerical simulations of the hydrodynamics and diffusion of the mixture of isotopes. Fast convergence of calculations is achieved due to exploring of a direct solver at the solution of the hydrodynamical and diffusion parts of the problem. Optimized separative power and optimal internal parameters of the Iguassu GC with 1 m rotor were calculated using the developed approach. Optimization procedure converges in 45 iterations taking 811 minutes.

Modeling of ion transport through a porous separator in vanadium redox flow batteries

NASA Astrophysics Data System (ADS)

Zhou, X. L.; Zhao, T. S.; An, L.; Zeng, Y. K.; Wei, L.

2016-09-01

In this work, we develop a two-dimensional, transient model to investigate the mechanisms of ion-transport through a porous separator in VRFBs and their effects on battery performance. Commercial-available separators with pore sizes of around 45 nm are particularly investigated and effects of key separator design parameters and operation modes are explored. We reveal that: i) the transport mechanism of vanadium-ion crossover through available separators is predominated by convection; ii) reducing the pore size below 15 nm effectively minimizes the convection-driven vanadium-ion crossover, while further reduction in migration- and diffusion-driven vanadium-ion crossover can be achieved only when the pore size is reduced to the level close to the sizes of vanadium ions; and iii) operation modes that can affect the pressure at the separator/electrode interface, such as the electrolyte flow rate, exert a significant influence on the vanadium-ion crossover rate through the available separators, indicating that it is critically important to equalize the pressure on each half-cell of a power pack in practical applications.

Research on multi - channel interactive virtual assembly system for power equipment under the “VR+” era

NASA Astrophysics Data System (ADS)

Ren, Yilong; Duan, Xitong; Wu, Lei; He, Jin; Xu, Wu

2017-06-01

With the development of the “VR+” era, the traditional virtual assembly system of power equipment has been unable to satisfy our growing needs. In this paper, based on the analysis of the traditional virtual assembly system of electric power equipment and the application of VR technology in the virtual assembly system of electric power equipment in our country, this paper puts forward the scheme of establishing the virtual assembly system of power equipment: At first, we should obtain the information of power equipment, then we should using OpenGL and multi texture technology to build 3D solid graphics library. After the completion of three-dimensional modeling, we can use the dynamic link library DLL package three-dimensional solid graphics generation program to realize the modularization of power equipment model library and power equipment model library generated hidden algorithm. After the establishment of 3D power equipment model database, we set up the virtual assembly system of 3D power equipment to separate the assembly operation of the power equipment from the space. At the same time, aiming at the deficiency of the traditional gesture recognition algorithm, we propose a gesture recognition algorithm based on improved PSO algorithm for BP neural network data glove. Finally, the virtual assembly system of power equipment can really achieve multi-channel interaction function.

Advanced Hydrogen Liquefaction Process

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

Schwartz, Joseph; Kromer, Brian; Neu, Ben

2011-09-28

The project identified and quantified ways to reduce the cost of hydrogen liquefaction, and reduce the cost of hydrogen distribution. The goal was to reduce the power consumption by 20% and then to reduce the capital cost. Optimizing the process, improving process equipment, and improving ortho-para conversion significantly reduced the power consumption of liquefaction, but by less than 20%. Because the efficiency improvement was less than the target, the program was stopped before the capital cost was addressed. These efficiency improvements could provide a benefit to the public to improve the design of future hydrogen liquefiers. The project increased themore » understanding of hydrogen liquefaction by modeling different processes and thoroughly examining ortho-para separation and conversion. The process modeling provided a benefit to the public because the project incorporated para hydrogen into the process modeling software, so liquefaction processes can be modeled more accurately than using only normal hydrogen. Adding catalyst to the first heat exchanger, a simple method to reduce liquefaction power, was identified, analyzed, and quantified. The demonstrated performance of ortho-para separation is sufficient for at least one identified process concept to show reduced power cost when compared to hydrogen liquefaction processes using conventional ortho-para conversion. The impact of improved ortho-para conversion can be significant because ortho para conversion uses about 20-25% of the total liquefaction power, but performance improvement is necessary to realize a substantial benefit. Most of the energy used in liquefaction is for gas compression. Improvements in hydrogen compression will have a significant impact on overall liquefier efficiency. Improvements to turbines, heat exchangers, and other process equipment will have less impact.« less

Afghanistan’s Constitutions: A Comparative Study and their Implications for Afghan Democratic Development

DTIC Science & Technology

2006-03-01

33 4. Relationship Between the Institutions of the State .........................34 a. Separation of Powers ..............................................................34...46 a. Separation of Powers ..............................................................46 b. Lines of Accountability...Institutions of the State .........................55 a. Separation of Powers ..............................................................55 b. Lines of

Removal of power line interference of space bearing vibration signal based on the morphological filter and blind source separation

NASA Astrophysics Data System (ADS)

Dong, Shaojiang; Sun, Dihua; Xu, Xiangyang; Tang, Baoping

2017-06-01

Aiming at the problem that it is difficult to extract the feature information from the space bearing vibration signal because of different noise, for example the running trend information, high-frequency noise and especially the existence of lot of power line interference (50Hz) and its octave ingredients of the running space simulated equipment in the ground. This article proposed a combination method to eliminate them. Firstly, the EMD is used to remove the running trend item information of the signal, the running trend that affect the signal processing accuracy is eliminated. Then the morphological filter is used to eliminate high-frequency noise. Finally, the components and characteristics of the power line interference are researched, based on the characteristics of the interference, the revised blind source separation model is used to remove the power line interferences. Through analysis of simulation and practical application, results suggest that the proposed method can effectively eliminate those noise.

On the kinetics of anaerobic power

PubMed Central

2012-01-01

Background This study investigated two different mathematical models for the kinetics of anaerobic power. Model 1 assumes that the work power is linear with the work rate, while Model 2 assumes a linear relationship between the alactic anaerobic power and the rate of change of the aerobic power. In order to test these models, a cross country skier ran with poles on a treadmill at different exercise intensities. The aerobic power, based on the measured oxygen uptake, was used as input to the models, whereas the simulated blood lactate concentration was compared with experimental results. Thereafter, the metabolic rate from phosphocreatine break down was calculated theoretically. Finally, the models were used to compare phosphocreatine break down during continuous and interval exercises. Results Good similarity was found between experimental and simulated blood lactate concentration during steady state exercise intensities. The measured blood lactate concentrations were lower than simulated for intensities above the lactate threshold, but higher than simulated during recovery after high intensity exercise when the simulated lactate concentration was averaged over the whole lactate space. This fit was improved when the simulated lactate concentration was separated into two compartments; muscles + internal organs and blood. Model 2 gave a better behavior of alactic energy than Model 1 when compared against invasive measurements presented in the literature. During continuous exercise, Model 2 showed that the alactic energy storage decreased with time, whereas Model 1 showed a minimum value when steady state aerobic conditions were achieved. During interval exercise the two models showed similar patterns of alactic energy. Conclusions The current study provides useful insight on the kinetics of anaerobic power. Overall, our data indicate that blood lactate levels can be accurately modeled during steady state, and suggests a linear relationship between the alactic anaerobic power and the rate of change of the aerobic power. PMID:22830586

PCA as a practical indicator of OPLS-DA model reliability.

PubMed

Worley, Bradley; Powers, Robert

Principal Component Analysis (PCA) and Orthogonal Projections to Latent Structures Discriminant Analysis (OPLS-DA) are powerful statistical modeling tools that provide insights into separations between experimental groups based on high-dimensional spectral measurements from NMR, MS or other analytical instrumentation. However, when used without validation, these tools may lead investigators to statistically unreliable conclusions. This danger is especially real for Partial Least Squares (PLS) and OPLS, which aggressively force separations between experimental groups. As a result, OPLS-DA is often used as an alternative method when PCA fails to expose group separation, but this practice is highly dangerous. Without rigorous validation, OPLS-DA can easily yield statistically unreliable group separation. A Monte Carlo analysis of PCA group separations and OPLS-DA cross-validation metrics was performed on NMR datasets with statistically significant separations in scores-space. A linearly increasing amount of Gaussian noise was added to each data matrix followed by the construction and validation of PCA and OPLS-DA models. With increasing added noise, the PCA scores-space distance between groups rapidly decreased and the OPLS-DA cross-validation statistics simultaneously deteriorated. A decrease in correlation between the estimated loadings (added noise) and the true (original) loadings was also observed. While the validity of the OPLS-DA model diminished with increasing added noise, the group separation in scores-space remained basically unaffected. Supported by the results of Monte Carlo analyses of PCA group separations and OPLS-DA cross-validation metrics, we provide practical guidelines and cross-validatory recommendations for reliable inference from PCA and OPLS-DA models.

Development of high-power dye laser chain

NASA Astrophysics Data System (ADS)

Konagai, Chikara; Kimura, Hironobu; Fukasawa, Teruichiro; Seki, Eiji; Abe, Motohisa; Mori, Hideo

2000-01-01

Copper vapor laser (CVL) pumped dye laser (DL) system, both in a master oscillator power amplifier (MOPA) configuration, has been developed for Atomic Vapor Isotope Separation program in Japan. Dye laser output power of about 500 W has been proved in long-term operations over 200 hours. High power fiber optic delivery system is utilized in order to efficiently transport kilowatt level CVL beams to the DL MOPA. Single model CVL pumped DL oscillator has been developed and worked for 200 hours within +/- 0.1 pm wavelength stability. Phase modulator for spreading spectrum to the linewidth of hyperfine structure has been developed and demonstrated.

Toward an Optimum Decision-Making Structure in Colleges: A Literature Review and Interpretation

ERIC Educational Resources Information Center

Helsabeck, Robert E.

1972-01-01

It seems that what is indicated for policies affecting student participation in campus governance is a mixed model, involving both communitarian structures for some decisions and a separation of powers for others. (Author)

Analysis and Test of a Proton Exchange Membrane Fuel Cell Power System for Space Power Applications

NASA Technical Reports Server (NTRS)

Vasquez, Arturo; Varanauski, Donald; Clark, Robert, Jr.

2000-01-01

An effort is underway to develop a prototype Proton Exchange Membrane (PEM) Fuel Cell breadboard system for fuhlre space applications. This prototype will be used to develop a comprehensive design basis for a space-rated PEM fuel cell powerplant. The prototype system includes reactant pressure regulators, ejector-based reactant pumps, a 4-kW fuel cell stack and cooling system, and a passive, membranebased oxygen / water separator. A computer model is being developed concurrently to analytically predict fluid flow in the oxidant reactant system. Fuel cells have historically played an important role in human-rated spacecraft. The Gemini and Apollo spacecraft used fuel cells for vehicle electrical power. The Space Shuttle currently uses three Alkaline Fuel Cell Powerplants (AFCP) to generate all of the vehicle's 15-20kW electrical power. Engineers at the Johnson Space Center have leveraged off the development effort ongoing in the commercial arena to develop PEM fuel cel ls for terrestrial uses. The prototype design originated from efforts to develop a PEM fuel cell replacement for the current Space Shuttle AFCP' s. In order to improve on the life and an already excellent hi storical record of reliability and safety, three subsystems were focused on. These were the fuel cell stack itself, the reactant circulation devices, and reactant / product water separator. PEM fuel cell stack performance is already demonstrating the potential for greater than four times the useful life of the current Shuttle's AFCP. Reactant pumping for product water removal has historically been accomplished with mechanical pumps. Ejectors offer an effective means of reactant pumping as well as the potential for weight reduction, control simplification, and long life. Centrifugal water separation is used on the current AFCP. A passive, membrane-based water separator offers compatibility with the micro-gravity environment of space, and the potential for control simplification, elimination of moving parts in an oxygen environment, and long life. The prototype system has been assembled from components that have previously been tested and evaluated at the component level. Preliminary data obtained from tests performed with the prototype system, as well as other published data, has been used to validate the analytical component models. These components have been incorporated into an integrated oxidant fluid system model. Results obtained from both the performance tests and the analytical model are presented.

War Powers Litigation Initiated by Members of Congress Since the Enactment of the War Powers Resolution

DTIC Science & Technology

2012-02-17

separation of powers . Prominent on the surface of any case held to involve a political question is found a textually demonstrable constitutional...and the U.S. Court of Appeals for the District of Columbia again affirmed. The district court stated as a predicate that the separation of powers doctrine...grave separation of powers issues” and observed that courts traditionally have been reluctant “to intercede in disputes between the political

The Proposed 2009 War Powers Consultation Act

DTIC Science & Technology

2009-03-19

both political branches of government participate in matters of national security. 15. SUBJECT TERMS Separation of Powers , National Security Law...Strategy Research Project DATE: 19 March 2009 WORD COUNT: 8,090 PAGES: 46 KEY TERMS: Separation of Powers , National Security Law, Constitution...Arthur Bestor, “ Separation of Powers in the Domain of Foreign Affairs: The Intent of the Constitution Historically Examined,” Seton Hall L. Rev. 5 (1974

Public Relations and Propaganda: Restrictions on Executive Agency Activities

DTIC Science & Technology

2005-03-21

Separation of Powers . . . . . . . . . . . . . . . . . . . . . . . . . . 9 Recent Legislation...the Separation of Powers The enforcement of restrictions against agency use of funds to employ publicity agents or to produce propaganda faces hurdles...propaganda encounters a separation of powers impediment. Congress, however, does possess tools to compel changes in agency behavior. Congress may

Separation of Powers in Foreign and Domestic Contexts.

ERIC Educational Resources Information Center

Bennett, Robert W.

1987-01-01

Explores the concept of separation of powers in terms of recent conflicts between the executive and legislative branches of the U.S. government. Points out that what the Supreme Court has said about separation of powers in the domestic context may complicate resolution of more serious problems in foreign affairs. (BSR)

Model for the separate collection of packaging waste in Portuguese low-performing recycling regions.

PubMed

Oliveira, V; Sousa, V; Vaz, J M; Dias-Ferreira, C

2018-06-15

Separate collection of packaging waste (glass; plastic/metals; paper/cardboard), is currently a widespread practice throughout Europe. It enables the recovery of good quality recyclable materials. However, separate collection performance are quite heterogeneous, with some countries reaching higher levels than others. In the present work, separate collection of packaging waste has been evaluated in a low-performance recycling region in Portugal in order to investigate which factors are most affecting the performance in bring-bank collection system. The variability of separate collection yields (kg per inhabitant per year) among 42 municipalities was scrutinized for the year 2015 against possible explanatory factors. A total of 14 possible explanatory factors were analysed, falling into two groups: socio-economic/demographic and waste collection service related. Regression models were built in an attempt to evaluate the individual effect of each factor on separate collection yields and predict changes on the collection yields by acting on those factors. The best model obtained is capable to explain 73% of the variation found in the separate collection yields. The model includes the following statistically significant indicators affecting the success of separate collection yields: i) inhabitants per bring-bank; ii) relative accessibility to bring-banks; iii) degree of urbanization; iv) number of school years attended; and v) area. The model presented in this work was developed specifically for the bring-bank system, has an explanatory power and quantifies the impact of each factor on separate collection yields. It can therefore be used as a support tool by local and regional waste management authorities in the definition of future strategies to increase collection of recyclables of good quality and to achieve national and regional targets. Copyright © 2017 Elsevier Ltd. All rights reserved.

Thermomechanical modelling of laser surface glazing for H13 tool steel

NASA Astrophysics Data System (ADS)

Kabir, I. R.; Yin, D.; Tamanna, N.; Naher, S.

2018-03-01

A two-dimensional thermomechanical finite element (FE) model of laser surface glazing (LSG) has been developed for H13 tool steel. The direct coupling technique of ANSYS 17.2 (APDL) has been utilised to solve the transient thermomechanical process. A H13 tool steel cylindrical cross-section has been modelled for laser power 200 W and 300 W at constant 0.2 mm beam width and 0.15 ms residence time. The model can predict temperature distribution, stress-strain increments in elastic and plastic region with time and space. The crack formation tendency also can be assumed by analysing the von Mises stress in the heat-concentrated zone. Isotropic and kinematic hardening models have been applied separately to predict the after-yield phenomena. At 200 W laser power, the peak surface temperature achieved is 1520 K which is below the melting point (1727 K) of H13 tool steel. For laser power 300 W, the peak surface temperature is 2523 K. Tensile residual stresses on surface have been found after cooling, which are in agreement with literature. Isotropic model shows higher residual stress that increases with laser power. Conversely, kinematic model gives lower residual stress which decreases with laser power. Therefore, both plasticity models could work in LSG for H13 tool steel.

A semiparametric spatio-temporal model for solar irradiance data

DOE PAGES

Patrick, Joshua D.; Harvill, Jane L.; Hansen, Clifford W.

2016-03-01

Here, we evaluate semiparametric spatio-temporal models for global horizontal irradiance at high spatial and temporal resolution. These models represent the spatial domain as a lattice and are capable of predicting irradiance at lattice points, given data measured at other lattice points. Using data from a 1.2 MW PV plant located in Lanai, Hawaii, we show that a semiparametric model can be more accurate than simple interpolation between sensor locations. We investigate spatio-temporal models with separable and nonseparable covariance structures and find no evidence to support assuming a separable covariance structure. These results indicate a promising approach for modeling irradiance atmore » high spatial resolution consistent with available ground-based measurements. Moreover, this kind of modeling may find application in design, valuation, and operation of fleets of utility-scale photovoltaic power systems.« less

Development of a Modular, Provider Customized Airway Trainer

DTIC Science & Technology

2015-11-25

Instructions for Airway Model with sensors and computer ( Raspberry PI ) ........................................ 31 Appendix B: Instructions for...Appendix A: Instructions for Airway Model with sensors and computer ( Raspberry PI ) RASPBERRY PI INSTRUCTIONS 1. Connect multicolor sensor...cable and two blue sensor cables (blue sensor cable orientation does not matter) 2. Plug in power to the screen and raspberry pi ( two separate

Stochastic modeling of neurobiological time series: Power, coherence, Granger causality, and separation of evoked responses from ongoing activity

NASA Astrophysics Data System (ADS)

Chen, Yonghong; Bressler, Steven L.; Knuth, Kevin H.; Truccolo, Wilson A.; Ding, Mingzhou

2006-06-01

In this article we consider the stochastic modeling of neurobiological time series from cognitive experiments. Our starting point is the variable-signal-plus-ongoing-activity model. From this model a differentially variable component analysis strategy is developed from a Bayesian perspective to estimate event-related signals on a single trial basis. After subtracting out the event-related signal from recorded single trial time series, the residual ongoing activity is treated as a piecewise stationary stochastic process and analyzed by an adaptive multivariate autoregressive modeling strategy which yields power, coherence, and Granger causality spectra. Results from applying these methods to local field potential recordings from monkeys performing cognitive tasks are presented.

A gravitationally lensed quasar with quadruple images separated by 14.62 arcseconds.

PubMed

Inada, Naohisa; Oguri, Masamune; Pindor, Bartosz; Hennawi, Joseph F; Chiu, Kuenley; Zheng, Wei; Ichikawa, Shin-Ichi; Gregg, Michael D; Becker, Robert H; Suto, Yasushi; Strauss, Michael A; Turner, Edwin L; Keeton, Charles R; Annis, James; Castander, Francisco J; Eisenstein, Daniel J; Frieman, Joshua A; Fukugita, Masataka; Gunn, James E; Johnston, David E; Kent, Stephen M; Nichol, Robert C; Richards, Gordon T; Rix, Hans-Walter; Sheldon, Erin Scott; Bahcall, Neta A; Brinkmann, J; Ivezić, Zeljko; Lamb, Don Q; McKay, Timothy A; Schneider, Donald P; York, Donald G

2003-12-18

Gravitational lensing is a powerful tool for the study of the distribution of dark matter in the Universe. The cold-dark-matter model of the formation of large-scale structures (that is, clusters of galaxies and even larger assemblies) predicts the existence of quasars gravitationally lensed by concentrations of dark matter so massive that the quasar images would be split by over 7 arcsec. Numerous searches for large-separation lensed quasars have, however, been unsuccessful. All of the roughly 70 lensed quasars known, including the first lensed quasar discovered, have smaller separations that can be explained in terms of galaxy-scale concentrations of baryonic matter. Although gravitationally lensed galaxies with large separations are known, quasars are more useful cosmological probes because of the simplicity of the resulting lens systems. Here we report the discovery of a lensed quasar, SDSS J1004 + 4112, which has a maximum separation between the components of 14.62 arcsec. Such a large separation means that the lensing object must be dominated by dark matter. Our results are fully consistent with theoretical expectations based on the cold-dark-matter model.

Russian Defense Legislation and Russian Democracy,

DTIC Science & Technology

1995-08-17

system denoting a President who is virtually unencumbered by the division of and separation of powers and by a system of checks and balances... separation of powers and is himself able to rule by decree. This trend to concentrate power in the President and in unresponsive executive branch...enhanced activity of the President is legally sanctioned along with the concept of rule by decree, a renunciation of separation of powers , exemption from

The hand that rocks the cradle rocks the boat: the empowerment of women.

PubMed

Turkel, Ann Ruth

2004-01-01

The obstacles to equality for women have changed from external to intrapsychic. The relational characteristics of women, such as nurturing and connecting with others, are now regarded as desirable attributes for the workplace. Adult growth and achievement models are based on the so-called masculine characteristics of separation, individuation, and independence. Relational theory supplies an alternative model called growth-in-connection, which stems from the feminine characteristics of connection, collectivity, and interdependence. Women's fears of exercising power, men's resistance to sharing power, the traditional ways in which women attain power are all concerns that are examined. Real power lies in exercising leadership, which implies risk-taking. Exploring the gender disequilibrium in issues of power--both the female advantage and the female disadvantage-as exemplified by the glass ceiling and its origins--helps to clarify the issues involved in empowerment.

Enemy Combatant Detainees: Habeas Corpus Challenges in Federal Court

DTIC Science & Technology

2009-01-29

46 Separation of Powers Issues...specifically intended to grant the authority of the President to adjudicate or remedy treaty violations could violate the doctrine of separation of powers , as...and prevent “cyclical abuses” of the writ by the executive and legislative branches.186 The Court stated that the separation - of - powers doctrine and

Enemy Combatant Detainees: Habeas Corpus Challenges in Federal Court

DTIC Science & Technology

2007-07-25

40 Separation of Powers Issues . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41 Eliminating...specifically intended to grant the authority of the President to adjudicate or remedy treaty violations could violate the doctrine of separation of powers , as...not serve to insulate such legislation from constitutional scrutiny. Separation of Powers Issues It is also clear that Congress may not exercise its

Spike avalanches in vivo suggest a driven, slightly subcritical brain state

PubMed Central

Priesemann, Viola; Wibral, Michael; Valderrama, Mario; Pröpper, Robert; Le Van Quyen, Michel; Geisel, Theo; Triesch, Jochen; Nikolić, Danko; Munk, Matthias H. J.

2014-01-01

In self-organized critical (SOC) systems avalanche size distributions follow power-laws. Power-laws have also been observed for neural activity, and so it has been proposed that SOC underlies brain organization as well. Surprisingly, for spiking activity in vivo, evidence for SOC is still lacking. Therefore, we analyzed highly parallel spike recordings from awake rats and monkeys, anesthetized cats, and also local field potentials from humans. We compared these to spiking activity from two established critical models: the Bak-Tang-Wiesenfeld model, and a stochastic branching model. We found fundamental differences between the neural and the model activity. These differences could be overcome for both models through a combination of three modifications: (1) subsampling, (2) increasing the input to the model (this way eliminating the separation of time scales, which is fundamental to SOC and its avalanche definition), and (3) making the model slightly sub-critical. The match between the neural activity and the modified models held not only for the classical avalanche size distributions and estimated branching parameters, but also for two novel measures (mean avalanche size, and frequency of single spikes), and for the dependence of all these measures on the temporal bin size. Our results suggest that neural activity in vivo shows a mélange of avalanches, and not temporally separated ones, and that their global activity propagation can be approximated by the principle that one spike on average triggers a little less than one spike in the next step. This implies that neural activity does not reflect a SOC state but a slightly sub-critical regime without a separation of time scales. Potential advantages of this regime may be faster information processing, and a safety margin from super-criticality, which has been linked to epilepsy. PMID:25009473

The Exoplanet Mass-Ratio Function From the MOA-II Survey: Discovery of a Break and Likely Peak at a Neptune Mass

NASA Technical Reports Server (NTRS)

Suzuki, D.; Bennett, D. P.; Sumi, T.; Bond, I. A.; Rogers, L. A.; Abe, F.; Asakura, Y.; Bhattacharya, A.; Donachie, M.; Freeman, M.;

Command in the 21st Century: An Introduction to Civil-Military Relations

DTIC Science & Technology

1998-06-01

pg. 77). This, of course, is easily said but not so easily operationalized. The separation of powers between different government entities muddies...around the distribution of power among the civilian elites rather than between civil authority and the military. The separation of powers provided by...34 separation of powers " and "checks and balances", civilian responsibility for and authority over the military is divided. The militia clauses divide

USSR Report, USA: Economics, Politics, Ideology, No. 9. September 1984.

DTIC Science & Technology

1984-12-10

refe- rences to the constitutional principle of the separation of powers and insisted on the effective exercise of powers by the Congress and the...authors of the constitution did not have our discomfort in mind when they composed this document. They wanted accounta- bility and the separation of powers . They...integral part of the constitutional separation of powers . The legislative veto, in accordance with the constitution, could be regarded as a legislative

Has Ukraine’s Path to Democracy Improved from Independence to the Orange Revolution

DTIC Science & Technology

2006-06-01

ineffective. "Even with dozens of amendments, it failed to define either the separation of powers between the legislature and the executive branches or...Providing for a complete separation of powers between the executive and legislative branches of government, it allowed the president "…to issue decrees...complete separation of powers between president and parliament and clearly defined presidential powers. . Ultimately, Ukraine seemed to be sliding

Far-Field Acoustic Power Level and Performance Analyses of F31/A31 Open Rotor Model at Simulated Scaled Takeoff, Nominal Takeoff, and Approach Conditions: Technical Report I

NASA Technical Reports Server (NTRS)

Sree, Dave

2015-01-01

Far-field acoustic power level and performance analyses of open rotor model F31/A31 have been performed to determine its noise characteristics at simulated scaled takeoff, nominal takeoff, and approach flight conditions. The nonproprietary parts of the data obtained from experiments in 9- by 15-Foot Low-Speed Wind Tunnel (9?15 LSWT) tests were provided by NASA Glenn Research Center to perform the analyses. The tone and broadband noise components have been separated from raw test data by using a new data analysis tool. Results in terms of sound pressure levels, acoustic power levels, and their variations with rotor speed, angle of attack, thrust, and input shaft power have been presented and discussed. The effect of an upstream pylon on the noise levels of the model has been addressed. Empirical equations relating model's acoustic power level, thrust, and input shaft power have been developed. The far-field acoustic efficiency of the model is also determined for various simulated flight conditions. It is intended that the results presented in this work will serve as a database for comparison and improvement of other open rotor blade designs and also for validating open rotor noise prediction codes.

Proconsuls and CINCs from the Roman Republic to the Republic of the United States of America: Lessons for the Pax Americana

DTIC Science & Technology

2001-05-01

find the best that foreign lands had to offer in constitutional theory. They found separation of powers within a mixed constitution. 60 The Greek...many of the Founding Fathers indeed knew Polybius, especially his passages on the Roman Constitution, and the separation of powers .”61 The separation ...lead 60 Marshall D. Lloyd, "Polybius and the Founding Fathers: the separation of powers ." Database on

Televising Supreme Court and Other Federal Court Proceedings: Legislation and Issues

DTIC Science & Technology

2006-11-08

proceedings, including the possible effect on judicial proceedings, separation of powers concerns, the purported educational value of such coverage, and...for Adverse Effects on Judicial Proceedings . . . . . . . . . . . . 11 Separation of Powers Concerns...proponents and opponents on myriad issues in the electronic media coverage debate — democratic values of government transparency, separation of powers , due

Enemy Combatant Detainees: Habeas Corpus Challenges in Federal Court

DTIC Science & Technology

2007-06-26

Separation of Powers Issues . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39 Eliminating Federal Court Jurisdiction Where There...specifically intended to grant the authority of the President to adjudicate or remedy treaty violations could violate the doctrine of separation of powers , as...does not serve to insulate such legislation from constitutional scrutiny. Separation of Powers Issues It is also clear that Congress may not

Enemy Combatant Detainees: Habeas Corpus Challenges in Federal Court

DTIC Science & Technology

2007-04-06

33 Separation of Powers Issues . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35 Eliminating...specifically intended to grant the authority of the President to adjudicate or remedy treaty violations could violate the doctrine of separation of powers , as...has wavered between two approaches to cases raising separation - of - powers claims, using a strict approach in some cases and a less rigid balancing

46 CFR 129.395 - Radio installations.

Code of Federal Regulations, 2014 CFR

2014-10-01

... INSTALLATIONS Power Sources and Distribution Systems § 129.395 Radio installations. A separate circuit, with... radios, if installed, may be powered from a local lighting power source, such as the pilothouse lighting panel, provided each radio power source has a separate overcurrent protection device. ...

46 CFR 129.395 - Radio installations.

Code of Federal Regulations, 2011 CFR

2011-10-01

... INSTALLATIONS Power Sources and Distribution Systems § 129.395 Radio installations. A separate circuit, with... radios, if installed, may be powered from a local lighting power source, such as the pilothouse lighting panel, provided each radio power source has a separate overcurrent protection device. ...

46 CFR 129.395 - Radio installations.

Code of Federal Regulations, 2012 CFR

2012-10-01

... INSTALLATIONS Power Sources and Distribution Systems § 129.395 Radio installations. A separate circuit, with... radios, if installed, may be powered from a local lighting power source, such as the pilothouse lighting panel, provided each radio power source has a separate overcurrent protection device. ...

46 CFR 129.395 - Radio installations.

Code of Federal Regulations, 2013 CFR

2013-10-01

... INSTALLATIONS Power Sources and Distribution Systems § 129.395 Radio installations. A separate circuit, with... radios, if installed, may be powered from a local lighting power source, such as the pilothouse lighting panel, provided each radio power source has a separate overcurrent protection device. ...

A numerical analysis to evaluate Betz's Law for vertical axis wind turbines

NASA Astrophysics Data System (ADS)

Thönnißen, F.; Marnett, M.; Roidl, B.; Schröder, W.

2016-09-01

The upper limit for the energy conversion rate of horizontal axis wind turbines (HAWT) is known as the Betz limit. Often this limit is also applied to vertical axis wind turbines (VAWT). However, a literature review reveals that early analytical and recent numerical approaches predicted values for the maximum power output of VAWTs close to or even higher than the Betz limit. Thus, it can be questioned whether the application of Betz's Law to VAWTs is justified. To answer this question, the current approach combines a free vortex model with a 2D inviscid panel code to represent the flow field of a generic VAWT. To ensure the validity of the model, an active blade pitch control system is used to avoid flow separation. An optimal pitch curve avoiding flow separation is determined for one specific turbine configuration by applying an evolutionary algorithm. The analysis yields a net power output that is slightly (≈6%) above the Betz limit. Besides the numerical result of an increased energy conversion rate, especially the identification of two physical power increasing mechanisms shows, that the application of Betz's Law to VAWTs is not justified.

Inlet Diameter and Flow Volume Effects on Separation and Energy Efficiency of Hydrocyclones

NASA Astrophysics Data System (ADS)

Erikli, Ş.; Olcay, A. B.

2015-08-01

This study investigates hydrocyclone performance of an oil injected screw compressor. Especially, the oil separation efficiency of a screw compressor plays a significant role for air quality and non-stop working hour of compressors has become an important issue when the efficiency in energy is considered. In this study, two separation efficiency parameters were selected to be hydrocyclone inlet diameter and flow volume height between oil reservoir surface and top of the hydrocyclone. Nine different cases were studied in which cyclone inlet diameter and flow volume height between oil reservoir surface and top were investigated in regards to separation and energy performance aspects and the effect of the parameters on the general performance appears to be causing powerful influence. Flow inside the hydrocyclone geometry was modelled by Reynolds Stress Model (RSM) and hydro particles were tracked by Discrete Phase Model (DPM). Besides, particle break up was modelled by the Taylor Analogy Breakup (TAB) model. The reversed vortex generation was observed at different planes. The upper limit of the inlet diameter of the cyclone yields the centrifugal force on particles to decrease while the flow becomes slower; and the larger diameter implies slower flow. On the contrary, the lower limit is increment in speed causes breakup problems that the particle diameters become smaller; consequently, it is harder to separate them from gas.

War Powers Revisited: The President, Congress and the Gulf War

DTIC Science & Technology

1992-04-01

Framers and Ratifiers, as well as the discussion over the separation of powers , the decision to shift to an offensive capability through increasing the...the president in future crises. The debate over separation of powers in November was brought into focus when 56 members of Congress filed suit against...the use of American forces without prior congressional approval which, in the minds of many, is a clear violation of the separation of powers . That

Investigation of two-phase phenomena occurring within moisture separator reheater high-level reactor trips at the Maanshan nuclear power plant

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

Ferng, Y.M.; Liao, L.Y.

1996-01-01

During the operating history of the Maanshan nuclear power plant (MNPP), five reactor trips have occurred as a result of the moisture separator reheater (MSR) high-level signal. These MSR high-level reactor trips have been a very serious concern, especially during the startup period of MNPP. Consequently, studying the physical phenomena of this particular event is worthwhile, and analytical work is performed using the RELAP5/MOD3 code to investigate the thermal-hydraulic phenomena of two-phase behaviors occurring within the MSR high-level reactor trips. The analytical model is first assessed against the experimental data obtained from several test loops. The same model can thenmore » be applied with confidence to the study of this topic. According to the present calculated results, the phenomena of liquid droplet accumulation ad residual liquid blowing in the horizontal section of cross-under-lines can be modeled. In addition, the present model can also predict the different increasing rates of inlet steam flow rate affecting the liquid accumulation within the cross-under-lines. The calculated conclusion is confirmed by the revised startup procedure of MNPP.« less

Optimizing the separation performance of a gas centrifuge

NASA Astrophysics Data System (ADS)

Wood, H. G.

1997-11-01

Gas centrifuges were originally developed for the enrichment of U^235 from naturally occurring uranium for the purpose of providing fuel for nuclear power reactors and material for nuclear weapons. This required the separation of a binary mixture composed of U^235 and U^238. Since the end of the cold war, a surplus of enriched uranium exists on the world market, but many centrifuge plants exist in numerous countries. These circumstances together with the growing demand for stable isotopes for chemical and physical research and in medical science has led to the exploration of alternate applications of gas centrifuge technology. In order to acieve these multi-component separations, existing centrifuges must be modified or new centrifuges must be designed. In either case, it is important to have models of the internal flow fields to predict the separation performance and algorithms to seek the optimal operating conditions of the centrifuges. Here, we use the Onsager pancake model of the internal flow field, and we present an optimization strategy which exploits a similarity parameter in the pancake model. Numerical examples will be presented.

Large-eddy simulation of flow in a plane, asymmetric diffuser

NASA Technical Reports Server (NTRS)

Kaltenbach, Hans-Jakob

1993-01-01

Recent improvements in subgrid-scale modeling as well as increases in computer power make it feasible to investigate flows using large-eddy simulation (LES) which have been traditionally studied with techniques based on Reynolds averaging. However, LES has not yet been applied to many flows of immediate technical interest. Preliminary results from LES of a plane diffuser flow are described. The long term goal of this work is to investigate flow separation as well as separation control in ducts and ramp-like geometries.

Scalable air cathode microbial fuel cells using glass fiber separators, plastic mesh supporters, and graphite fiber brush anodes.

PubMed

Zhang, Xiaoyuan; Cheng, Shaoan; Liang, Peng; Huang, Xia; Logan, Bruce E

2011-01-01

The combined use of brush anodes and glass fiber (GF1) separators, and plastic mesh supporters were used here for the first time to create a scalable microbial fuel cell architecture. Separators prevented short circuiting of closely-spaced electrodes, and cathode supporters were used to avoid water gaps between the separator and cathode that can reduce power production. The maximum power density with a separator and supporter and a single cathode was 75 ± 1 W/m(3). Removing the separator decreased power by 8%. Adding a second cathode increased power to 154 ± 1 W/m(3). Current was increased by connecting two MFCs connected in parallel. These results show that brush anodes, combined with a glass fiber separator and a plastic mesh supporter, produce a useful MFC architecture that is inherently scalable due to good insulation between the electrodes and a compact architecture. Copyright © 2010 Elsevier Ltd. All rights reserved.

Laissez-Faire : Fully Asymmetric Backscatter Communication

PubMed Central

Hu, Pan; Zhang, Pengyu; Ganesan, Deepak

2016-01-01

Backscatter provides dual-benefits of energy harvesting and low-power communication, making it attractive to a broad class of wireless sensors. But the design of a protocol that enables extremely power-efficient radios for harvesting-based sensors as well as high-rate data transfer for data-rich sensors presents a conundrum. In this paper, we present a new fully asymmetric backscatter communication protocol where nodes blindly transmit data as and when they sense. This model enables fully flexible node designs, from extraordinarily power-efficient backscatter radios that consume barely a few micro-watts to high-throughput radios that can stream at hundreds of Kbps while consuming a paltry tens of micro-watts. The challenge, however, lies in decoding concurrent streams at the reader, which we achieve using a novel combination of time-domain separation of interleaved signal edges, and phase-domain separation of colliding transmissions. We provide an implementation of our protocol, LF-Backscatter, and show that it can achieve an order of magnitude or more improvement in throughput, latency and power over state-of-art alternatives. PMID:28286885

Measuring neuronal avalanches in disordered systems with absorbing states

NASA Astrophysics Data System (ADS)

Girardi-Schappo, M.; Tragtenberg, M. H. R.

2018-04-01

Power-law-shaped avalanche-size distributions are widely used to probe for critical behavior in many different systems, particularly in neural networks. The definition of avalanche is ambiguous. Usually, theoretical avalanches are defined as the activity between a stimulus and the relaxation to an inactive absorbing state. On the other hand, experimental neuronal avalanches are defined by the activity between consecutive silent states. We claim that the latter definition may be extended to some theoretical models to characterize their power-law avalanches and critical behavior. We study a system in which the separation of driving and relaxation time scales emerges from its structure. We apply both definitions of avalanche to our model. Both yield power-law-distributed avalanches that scale with system size in the critical point as expected. Nevertheless, we find restricted power-law-distributed avalanches outside of the critical region within the experimental procedure, which is not expected by the standard theoretical definition. We remark that these results are dependent on the model details.

The Role of States in Cleanup of Hazardous Waste at Federal Facilities

DTIC Science & Technology

1993-09-01

Our founding fathers had a fear of the legislature and the power that it might try to take. There are two separation - of - powers doctrines that may...amend. X. 55 Before looking at those two areas, however, it must be determined whether or not separation - of - powers , a horizontal doctrine which...Airports Authority (MWAA), which was a creature of state law, on the basis of the separation - of - powers doctrine. In this case the Board was established by

Early and Later Life Stress Alter Brain Activity and Sleep in Rats

PubMed Central

Mrdalj, Jelena; Pallesen, Ståle; Milde, Anne Marita; Jellestad, Finn Konow; Murison, Robert; Ursin, Reidun; Bjorvatn, Bjørn; Grønli, Janne

2013-01-01

Exposure to early life stress may profoundly influence the developing brain in lasting ways. Neuropsychiatric disorders associated with early life adversity may involve neural changes reflected in EEG power as a measure of brain activity and disturbed sleep. The main aim of the present study was for the first time to characterize possible changes in adult EEG power after postnatal maternal separation in rats. Furthermore, in the same animals, we investigated how EEG power and sleep architecture were affected after exposure to a chronic mild stress protocol. During postnatal day 2–14 male rats were exposed to either long maternal separation (180 min) or brief maternal separation (10 min). Long maternally separated offspring showed a sleep-wake nonspecific reduction in adult EEG power at the frontal EEG derivation compared to the brief maternally separated group. The quality of slow wave sleep differed as the long maternally separated group showed lower delta power in the frontal-frontal EEG and a slower reduction of the sleep pressure. Exposure to chronic mild stress led to a lower EEG power in both groups. Chronic exposure to mild stressors affected sleep differently in the two groups of maternal separation. Long maternally separated offspring showed more total sleep time, more episodes of rapid eye movement sleep and higher percentage of non-rapid eye movement episodes ending in rapid eye movement sleep compared to brief maternal separation. Chronic stress affected similarly other sleep parameters and flattened the sleep homeostasis curves in all offspring. The results confirm that early environmental conditions modulate the brain functioning in a long-lasting way. PMID:23922857

The statistical overlap theory of chromatography using power law (fractal) statistics.

PubMed

Schure, Mark R; Davis, Joe M

2011-12-30

The chromatographic dimensionality was recently proposed as a measure of retention time spacing based on a power law (fractal) distribution. Using this model, a statistical overlap theory (SOT) for chromatographic peaks is developed that estimates the number of peak maxima as a function of the chromatographic dimension, saturation and scale. Power law models exhibit a threshold region whereby below a critical saturation value no loss of peak maxima due to peak fusion occurs as saturation increases. At moderate saturation, behavior is similar to the random (Poisson) peak model. At still higher saturation, the power law model shows loss of peaks nearly independent of the scale and dimension of the model. The physicochemical meaning of the power law scale parameter is discussed and shown to be equal to the Boltzmann-weighted free energy of transfer over the scale limits. The scale is discussed. Small scale range (small β) is shown to generate more uniform chromatograms. Large scale range chromatograms (large β) are shown to give occasional large excursions of retention times; this is a property of power laws where "wild" behavior is noted to occasionally occur. Both cases are shown to be useful depending on the chromatographic saturation. A scale-invariant model of the SOT shows very simple relationships between the fraction of peak maxima and the saturation, peak width and number of theoretical plates. These equations provide much insight into separations which follow power law statistics. Copyright © 2011 Elsevier B.V. All rights reserved.

Single-hole spectral function and spin-charge separation in the t-J model

NASA Astrophysics Data System (ADS)

Mishchenko, A. S.; Prokof'ev, N. V.; Svistunov, B. V.

2001-07-01

Worm algorithm Monte Carlo simulations of the hole Green function with subsequent spectral analysis were performed for 0.1<=J/t<=0.4 on lattices with up to L×L=32×32 sites at a temperature as low as T=J/40, and present, apparently, the hole spectral function in the thermodynamic limit. Spectral analysis reveals a δ-function-sharp quasiparticle peak at the lower edge of the spectrum that is incompatible with the power-law singularity and thus rules out the possibility of spin-charge separation in this parameter range. Spectral continuum features two peaks separated by a gap ~4÷5 t.

Rapid prototyping and parametric optimization of plastic acoustofluidic devices for blood-bacteria separation.

PubMed

Silva, R; Dow, P; Dubay, R; Lissandrello, C; Holder, J; Densmore, D; Fiering, J

2017-09-01

Acoustic manipulation has emerged as a versatile method for microfluidic separation and concentration of particles and cells. Most recent demonstrations of the technology use piezoelectric actuators to excite resonant modes in silicon or glass microchannels. Here, we focus on acoustic manipulation in disposable, plastic microchannels in order to enable a low-cost processing tool for point-of-care diagnostics. Unfortunately, the performance of resonant acoustofluidic devices in plastic is hampered by a lack of a predictive model. In this paper, we build and test a plastic blood-bacteria separation device informed by a design of experiments approach, parametric rapid prototyping, and screening by image-processing. We demonstrate that the new device geometry can separate bacteria from blood while operating at 275% greater flow rate as well as reduce the power requirement by 82%, while maintaining equivalent separation performance and resolution when compared to the previously published plastic acoustofluidic separation device.

New model of inverting substation for DC traction with regenerative braking system

NASA Astrophysics Data System (ADS)

Omar, Abdul Malek Saidina; Samat, Ahmad Asri Abd; Isa, Siti Sarah Mat; Shamsuddin, Sarah Addyani; Jamaludin, Nur Fadhilah; Khyasudeen, Muhammad Farris

2017-08-01

This paper presents a power electronic devices application focus on modeling, analysis, and control of switching power converter in the inverting DC substation with regenerative braking system which is used to recycle the surplus regenerative power by feed it back to the main AC grid. The main objective of this research is to improve the switching power electronic converter of the railway inverting substation and optimize the maximum kinetic energy recovery together with minimum power losses from the railway braking system. Assess performance including efficiency and robustness will be evaluated in order to get the best solution for the design configuration. Research methodology included mathematical calculation, simulation, and detail analysis on modeling of switching power converter on inverting substation. The design stage separates to four main areas include rectification mode, regenerative mode, control inverter mode and filtering mode. The simulation result has shown that the regenerative inverter has a capability to accept a maximum recovery power on the regeneration mode. Total energy recovery has increase and power losses have decreases because inverter abilities to transfer the surplus energy back to the main AC supply. An Inverter controller with PWM Generator and PI Voltage Regulator has been designed to control voltage magnitude and frequency of the DC traction system.

A Compelling Solution to Guantanamo Bay

DTIC Science & Technology

2013-03-01

military commission violated separation of powers because one branch of the government, namely the Executive, controlled all aspects of the case... separation of powers requirement. The conclusion that can be drawn from these legal decisions is that the military system is fundamentally...the Rule of Law and violates the separation of powers .111 The current system has even strained the United States’ relationship with close allies

Fourier power spectra of the geomagnetic field for circular paths on the Earth's surface.

USGS Publications Warehouse

Alldredge, L.R.; Benton, E.R.

1986-01-01

The Fourier power spectra of geomagnetic component values, synthesized from spherical harmonic models, have been computed for circular paths on the Earth's surface. They are not found to be more useful than is the spectrum of magnetic energy outside the Earth for the purpose of separating core and crustal sources of the geomagnetic field. The Fourier power spectra of N and E geomagnetic components along nearly polar great circle paths exhibit some unusual characteristics that are explained by the geometric perspective of Fourier series on spheres developed by Yee. -Authors

Qualitative modeling of silica plasma etching using neural network

NASA Astrophysics Data System (ADS)

Kim, Byungwhan; Kwon, Kwang Ho

2003-01-01

An etching of silica thin film is qualitatively modeled by using a neural network. The process was characterized by a 23 full factorial experiment plus one center point, in which the experimental factors and ranges include 100-800 W radio-frequency source power, 100-400 W bias power and gas flow rate ratio CHF3/CF4. The gas flow rate ratio varied from 0.2 to 5.0. The backpropagation neural network (BPNN) was trained on nine experiments and tested on six experiments, not pertaining to the original training data. The prediction ability of the BPNN was optimized as a function of the training parameters. Prediction errors are 180 Å/min and 1.33, for the etch rate and anisotropy models, respectively. Physical etch mechanisms were estimated from the three-dimensional plots generated from the optimized models. Predicted response surfaces were consistent with experimentally measured etch data. The dc bias was correlated to the etch responses to evaluate its contribution. Both the source power (plasma density) and bias power (ion directionality) strongly affected the etch rate. The source power was the most influential factor for the etch rate. A conflicting effect between the source and bias powers was noticed with respect to the anisotropy. The dc bias played an important role in understanding or separating physical etch mechanisms.

VizieR Online Data Catalog: Wide binaries in Tycho-Gaia: search method (Andrews+, 2017)

NASA Astrophysics Data System (ADS)

Andrews, J. J.; Chaname, J.; Agueros, M. A.

2017-11-01

Our catalogue of wide binaries identified in the Tycho-Gaia Astrometric Solution catalogue. The Gaia source IDs, Tycho IDs, astrometry, posterior probabilities for both the log-flat prior and power-law prior models, and angular separation are presented. (1 data file).

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

Ahedo, Eduardo; Merino, Mario

A previous axisymmetric model of the supersonic expansion of a collisionless, hot plasma in a divergent magnetic nozzle is extended here in order to include electron-inertia effects. Up to dominant order on all components of the electron velocity, electron momentum equations still reduce to three conservation laws. Electron inertia leads to outward electron separation from the magnetic streamtubes. The progressive plasma filling of the adjacent vacuum region is consistent with electron-inertia being part of finite electron Larmor radius effects, which increase downstream and eventually demagnetize the plasma. Current ambipolarity is not fulfilled and ion separation can be either outwards ormore » inwards of magnetic streamtubes, depending on their magnetization. Electron separation penalizes slightly the plume efficiency and is larger for plasma beams injected with large pressure gradients. An alternative nonzero electron-inertia model [E. Hooper, J. Propul. Power 9, 757 (1993)] based on cold plasmas and current ambipolarity, which predicts inwards electron separation, is discussed critically. A possible competition of the gyroviscous force with electron-inertia effects is commented briefly.« less

Testing cross-phenotype effects of rare variants in longitudinal studies of complex traits.

PubMed

Rudra, Pratyaydipta; Broadaway, K Alaine; Ware, Erin B; Jhun, Min A; Bielak, Lawrence F; Zhao, Wei; Smith, Jennifer A; Peyser, Patricia A; Kardia, Sharon L R; Epstein, Michael P; Ghosh, Debashis

2018-06-01

Many gene mapping studies of complex traits have identified genes or variants that influence multiple phenotypes. With the advent of next-generation sequencing technology, there has been substantial interest in identifying rare variants in genes that possess cross-phenotype effects. In the presence of such effects, modeling both the phenotypes and rare variants collectively using multivariate models can achieve higher statistical power compared to univariate methods that either model each phenotype separately or perform separate tests for each variant. Several studies collect phenotypic data over time and using such longitudinal data can further increase the power to detect genetic associations. Although rare-variant approaches exist for testing cross-phenotype effects at a single time point, there is no analogous method for performing such analyses using longitudinal outcomes. In order to fill this important gap, we propose an extension of Gene Association with Multiple Traits (GAMuT) test, a method for cross-phenotype analysis of rare variants using a framework based on the distance covariance. The approach allows for both binary and continuous phenotypes and can also adjust for covariates. Our simple adjustment to the GAMuT test allows it to handle longitudinal data and to gain power by exploiting temporal correlation. The approach is computationally efficient and applicable on a genome-wide scale due to the use of a closed-form test whose significance can be evaluated analytically. We use simulated data to demonstrate that our method has favorable power over competing approaches and also apply our approach to exome chip data from the Genetic Epidemiology Network of Arteriopathy. © 2018 WILEY PERIODICALS, INC.

Analysis of closed cycle megawatt class space power systems with nuclear reactor heat sources

NASA Technical Reports Server (NTRS)

Juhasz, A. J.; Jones, B. I.

1987-01-01

The analysis and integration studies of multimegawatt nuclear power conversion systems for potential SDI applications is presented. A study is summarized which considered 3 separate types of power conversion systems for steady state power generation with a duty requirement of 1 yr at full power. The systems considered are based on the following conversion cycles: direct and indirect Brayton gas turbine, direct and indirect liquid metal Rankine, and in core thermionic. A complete mass analysis was performed for each system at power levels ranging from 1 to 25 MWe for both heat pipe and liquid droplet radiator options. In the modeling of common subsystems, reactor and shield calculations were based on multiparameter correlation and an in-house analysis for the heat rejection and other subsystems.

Saturn systems holddown acoustic efficiency and normalized acoustic power spectrum.

NASA Technical Reports Server (NTRS)

Gilbert, D. W.

1972-01-01

Saturn systems field acoustic data are used to derive mid- and far-field prediction parameters for rocket engine noise. The data were obtained during Saturn vehicle launches at the Kennedy Space Center. The data base is a sorted set of acoustic data measured during the period 1961 through 1971 for Saturn system launches SA-1 through AS-509. The model assumes hemispherical radiation from a simple source located at the intersection of the longitudinal axis of each booster and the engine exit plane. The model parameters are evaluated only during vehicle holddown. The acoustic normalized power spectrum and efficiency for each system are isolated as a composite from the data using linear numerical methods. The specific definitions of each allows separation. The resulting power spectra are nondimensionalized as a function of rocket engine parameters. The nondimensional Saturn system acoustic spectrum and efficiencies are compared as a function of Strouhal number with power spectra from other systems.

Model of Energy Spectrum Parameters of Ground Level Enhancement Events in Solar Cycle 23

NASA Astrophysics Data System (ADS)

Wu, S.-S.; Qin, G.

2018-01-01

Mewaldt et al. (2012) fitted the observations of the ground level enhancement (GLE) events during solar cycle 23 to the double power law equation to obtain the four spectral parameters, the normalization constant C, low-energy power law slope γ1, high-energy power law slope γ2, and break energy E0. There are 16 GLEs from which we select 13 for study by excluding some events with complicated situation. We analyze the four parameters with conditions of the corresponding solar events. According to solar event conditions, we divide the GLEs into two groups, one with strong acceleration by interplanetary shocks and another one without strong acceleration. By fitting the four parameters with solar event conditions we obtain models of the parameters for the two groups of GLEs separately. Therefore, we establish a model of energy spectrum of solar cycle 23 GLEs, which may be used in prediction in the future.

Hierarchy of Modes in an Interacting One-Dimensional System

NASA Astrophysics Data System (ADS)

Tsyplyatyev, O.; Schofield, A. J.; Jin, Y.; Moreno, M.; Tan, W. K.; Ford, C. J. B.; Griffiths, J. P.; Farrer, I.; Jones, G. A. C.; Ritchie, D. A.

2015-05-01

Studying interacting fermions in one dimension at high energy, we find a hierarchy in the spectral weights of the excitations theoretically, and we observe evidence for second-level excitations experimentally. Diagonalizing a model of fermions (without spin), we show that levels of the hierarchy are separated by powers of R2/L2, where R is a length scale related to interactions and L is the system length. The first-level (strongest) excitations form a mode with parabolic dispersion, like that of a renormalized single particle. The second-level excitations produce a singular power-law line shape to the first-level mode and multiple power laws at the spectral edge. We measure momentum-resolved tunneling of electrons (fermions with spin) from or to a wire formed within a GaAs heterostructure, which shows parabolic dispersion of the first-level mode and well-resolved spin-charge separation at low energy with appreciable interaction strength. We find structure resembling the second-level excitations, which dies away quite rapidly at high momentum.

Observation of a hierarchy of modes in an interacting one-dimensional system

NASA Astrophysics Data System (ADS)

Ford, Christopher; Moreno, Maria; Jin, Yiqing; Tan, Wooi Kiat; Griffiths, Jon; Farrer, Ian; Jones, Geb; Anthore, Anne; Ritchie, David; Tsyplyatyev, Oleksandr; Schofield, Andrew

2015-03-01

Studying interacting fermions in 1D at high energy, we find a hierarchy in the spectral weights of the excitations theoretically and we observe evidence for second-level excitations experimentally. Diagonalising a model of fermions (without spin), we show that levels of the hierarchy are separated by powers of 2 /L2 , where  is a length-scale related to interactions and L is the system length. The first-level (strongest) excitations form a mode with parabolic dispersion, like that of a renormalised single particle. The second-level excitations produce a singular power-law line shape to the first-level mode and multiple power-laws at the spectral edge. We measure momentum-resolved tunneling of electrons (fermions with spin) from/to a wire formed within a GaAs heterostructure, which shows parabolic dispersion of the first-level mode and well-resolved spin-charge separation at low energy with appreciable interaction strength. We find structure resembling the second-level excitations, which dies away quite rapidly at high momentum.

Pc-5 wave power in the plasmasphere and trough: CRRES observations

NASA Astrophysics Data System (ADS)

Hartinger, M.; Moldwin, M.; Angelopoulos, V.; Takahashi, K.; Singer, H. J.; Anderson, R. R.

2009-12-01

The CRRES (Combined Release and Radiation Effects Satellite) mission provides an opportunity to study the distribution of MHD wave power in the inner magnetosphere both inside the high-density plasmasphere and in the low-density trough. We present a statistical survey of Pc-5 wave power using CRRES magnetometer and plasma wave data separated into plasmasphere and trough intervals. Using a database of plasmapause crossings, we examined differences in power spectral density between the plasmasphere and trough regions. We found significant differences between the plasmasphere and trough in the radial profiles of Pc-5 wave power. On average, wave power was higher in the trough, but the difference in power depended on magnetic local time. Our study shows that determining the plasmapause location is important for understanding and modeling the MHD wave environment in the Pc-5 frequency band.

Ammonia producing engine utilizing oxygen separation

DOEpatents

Easley, Jr., William Lanier; Coleman, Gerald Nelson [Petersborough, GB; Robel, Wade James [Peoria, IL

2008-12-16

A power system is provided having a power source, a first power source section with a first intake passage and a first exhaust passage, a second power source section with a second intake passage and a second exhaust passage, and an oxygen separator. The second intake passage may be fluidly isolated from the first intake passage.

The Air Force Officer and the Constitution

DTIC Science & Technology

2010-02-17

2. Enumerated Powers 3. Separation of Powers and Checks and Balances C. Ways to amend the U.S. Constitution D. The elements of the U.S...the courts ▪ judicial 14. What stops one branch of government from becoming too powerful? ▪ checks and balances ▪ separation of powers 15. Who

High-Power Collective Charging of a Solid-State Quantum Battery

NASA Astrophysics Data System (ADS)

Ferraro, Dario; Campisi, Michele; Andolina, Gian Marcello; Pellegrini, Vittorio; Polini, Marco

2018-03-01

Quantum information theorems state that it is possible to exploit collective quantum resources to greatly enhance the charging power of quantum batteries (QBs) made of many identical elementary units. We here present and solve a model of a QB that can be engineered in solid-state architectures. It consists of N two-level systems coupled to a single photonic mode in a cavity. We contrast this collective model ("Dicke QB"), whereby entanglement is genuinely created by the common photonic mode, to the one in which each two-level system is coupled to its own separate cavity mode ("Rabi QB"). By employing exact diagonalization, we demonstrate the emergence of a quantum advantage in the charging power of Dicke QBs, which scales like √{N } for N ≫1 .

The optimization air separation plants for combined cycle MHD-power plant applications

NASA Technical Reports Server (NTRS)

Juhasz, A. J.; Springmann, H.; Greenberg, R.

1980-01-01

Some of the design approaches being employed during a current supported study directed at developing an improved air separation process for the production of oxygen enriched air for magnetohydrodynamics (MHD) combustion are outlined. The ultimate objective is to arrive at conceptual designs of air separation plants, optimized for minimum specific power consumption and capital investment costs, for integration with MHD combined cycle power plants.

Congressional Authority to Limit U.S. Military Operations in Iraq

DTIC Science & Technology

2007-01-29

troops, and any efforts on the part of Congress to intervene could represent an unconstitutional violation of separation - of - powers principles. While...of separation - of - powers principles. While even proponents of strong executive prerogative in matters of war appear to concede that it is within...Grimmett. 41 See Reid Skibell, Separation - of - Powers and the Commander in Chief: Congress’s Authority to Override Presidential Decisions in Crisis Situations

[Fast separation and analysis of water-soluble vitamins in spinach by capillary electrophoresis with high voltage].

PubMed

Hu, Xiaoqin; You, Huiyan

2009-11-01

In capillary electrophoresis, 0-40 kV (even higher) voltage can be reached by a connecting double-model high voltage power supply. In the article, water-soluble vitamins, VB1, VB2, VB6, VC, calcium D-pantothenate, D-biotin, nicotinic acid and folic acid in vegetable, were separated by using the high voltage power supply under the condition of electrolyte water solution as running buffer. The separation conditions, such as voltage, the concentration of buffer and pH value etc. , were optimized during the experiments. The results showed that eight water-soluble vitamins could be baseline separated in 2.2 min at 40 kV applied voltage, 25 mmol/L sodium tetraborate buffer solution (pH 8.8). The water-soluble vitamins in spinach were quantified and the results were satisfied. The linear correlation coefficients of the water-soluble vitamins ranged from 0.9981 to 0.9999. The detection limits ranged from 0.2 to 0.3 mg/L. The average recoveries ranged from 88.0% to 100.6% with the relative standard deviations (RSD) range of 1.15%-4.13% for the spinach samples.

The West German Chancellor and the Study of Comparative Executives.

ERIC Educational Resources Information Center

Berry, Phyllis

1989-01-01

Describes how the West German parliamentary government, although originally modeled after the British parliament, is different because it allows for separation of powers similar to the U.S. government. Illustrates how a teacher can use an examination of the executive office to describe governmental relationships. (GG)

A Feminist Critique of Rational-Choice Theories: Implications for Sociology.

ERIC Educational Resources Information Center

England, Paula

1989-01-01

Provides a feminist critique of rational-choice theory and the interdisciplinary feminist theories of sociology. Applies the separative model of self to four assumptions of the neoclassical economics version of rational-choice theory. Uses research on marital power to illustrate how removing distorting assumptions can help illuminate sociological…

Radiated Sound Power from a Curved Honeycomb Panel

NASA Technical Reports Server (NTRS)

Robinson, Jay H.; Buehrle, Ralph D.; Klos, Jacob; Grosveld, Ferdinand W.

2003-01-01

The validation of finite element and boundary element model for the vibro-acoustic response of a curved honeycomb core composite aircraft panel is completed. The finite element and boundary element models were previously validated separately. This validation process was hampered significantly by the method in which the panel was installed in the test facility. The fixture used was made primarily of fiberboard and the panel was held in a groove in the fiberboard by a compression fitting made of plastic tubing. The validated model is intended to be used to evaluate noise reduction concepts from both an experimental and analytic basis simultaneously. An initial parametric study of the influence of core thickness on the radiated sound power from this panel, using this numerical model was subsequently conducted. This study was significantly influenced by the presence of strong boundary condition effects but indicated that the radiated sound power from this panel was insensitive to core thickness primarily due to the offsetting effects of added mass and added stiffness in the frequency range investigated.

The American Civil-Military Relationship: A Delicate Balance

DTIC Science & Technology

2008-01-01

important Constitutional safeguards consistent with the separation of powers . The power to control appropriations to the national military...existence of a functional Constitution system prevented the emerging standing army from wresting control of the United States through the separation of powers . A

Presidential Signing Statements: Constitutional and Institutional Implications

DTIC Science & Technology

2007-04-13

Association (ABA) recently publishing a report declaring that these instruments are “contrary to the rule of law and our constitutional separation of powers ” when...Force on Presidential Signing Statements and the Separation of Powers Doctrine at p. 5 (August 2006). Presidential Signing Statements: Constitutional...constitutional separation of powers ” when they “claim the authority or state the intention to disregard or decline to enforce all or part of a law...or to

Moral Courage or Heresy: The Benefits and Pitfalls of Military Leaders Speaking Out

DTIC Science & Technology

2008-01-01

available, the threat of judicial intelference with the Executive Branch would violate separation of powers . Held: l.This Court need not address two...claim in this case. (b) The separation - of - powers doctrine does not require federal courts to stay all private actions against the President until he...scheduling orders, potential contempt citations, and sanctions would violate separation of powers principles. Judge Bowman suggested that "judicial case

Boumediene v. Bush: Guantanamo Detainees’ Right to Habeas Corpus

DTIC Science & Technology

2008-06-16

executive and legislative branches.12 The Court stated that the separation - of - powers doctrine and the history shaping the design of the CRS-4 13 Id. at...the government’s sovereignty-based approach to the Constitution’s applicability would raise significant separation - of - powers concerns, as the political...is itself an indispensable mechanism for monitoring the separation of powers . The test for determining the scope of this provision must not be

Unintended Consequences of the Goldwater-Nichols Act (Joint Force Quarterly, Spring 1998)

DTIC Science & Technology

1998-01-01

Armed Forces to achieve mili- tary success, the unified direction of DOD neces- sary for budgetary efficiency, and the separation of powers demanded by...its actions. The Constitution has stood for two centuries precisely because it flexibly applies simple concepts such as the separation of powers and...replaced, it has created a national military command structure that ignores the separation of powers . The amended National Security Act has consolidated

The Iran Hostages: Efforts to Obtain Compensation

DTIC Science & Technology

2013-11-01

manner that raised constitutional separation of powers concerns.51 It also chastised the plaintiffs’ attorneys for what it said were serious...argument contains,” the court said, “it is absolutely without basis in law.” Id. at 168. 51 The court did not base its decision on any separation of powers considerations...of jurisdiction [would raise] serious separation of powers concerns” and might be “an impermissible encroachment by Congress into the sphere of the

Combustion systems and power plants incorporating parallel carbon dioxide capture and sweep-based membrane separation units to remove carbon dioxide from combustion gases

DOEpatents

Wijmans, Johannes G [Menlo Park, CA; Merkel, Timothy C [Menlo Park, CA; Baker, Richard W [Palo Alto, CA

2011-10-11

Disclosed herein are combustion systems and power plants that incorporate sweep-based membrane separation units to remove carbon dioxide from combustion gases. In its most basic embodiment, the invention is a combustion system that includes three discrete units: a combustion unit, a carbon dioxide capture unit, and a sweep-based membrane separation unit. In a preferred embodiment, the invention is a power plant including a combustion unit, a power generation system, a carbon dioxide capture unit, and a sweep-based membrane separation unit. In both of these embodiments, the carbon dioxide capture unit and the sweep-based membrane separation unit are configured to be operated in parallel, by which we mean that each unit is adapted to receive exhaust gases from the combustion unit without such gases first passing through the other unit.

Rotary drum separator system

NASA Technical Reports Server (NTRS)

Barone, Michael R. (Inventor); Murdoch, Karen (Inventor); Scull, Timothy D. (Inventor); Fort, James H. (Inventor)

2009-01-01

A rotary phase separator system generally includes a step-shaped rotary drum separator (RDS) and a motor assembly. The aspect ratio of the stepped drum minimizes power for both the accumulating and pumping functions. The accumulator section of the RDS has a relatively small diameter to minimize power losses within an axial length to define significant volume for accumulation. The pumping section of the RDS has a larger diameter to increase pumping head but has a shorter axial length to minimize power losses. The motor assembly drives the RDS at a low speed for separating and accumulating and a higher speed for pumping.

Mixed H2/H∞ pitch control of wind turbine with a Markovian jump model

NASA Astrophysics Data System (ADS)

Lin, Zhongwei; Liu, Jizhen; Wu, Qiuwei; Niu, Yuguang

2018-01-01

This paper proposes a Markovian jump model and the corresponding H2/H∞ control strategy for the wind turbine driven by the stochastic switching wind speed, which can be used to regulate the generator speed in order to harvest the rated power while reducing the fatigue loads on the mechanical side of wind turbine. Through sampling the low-frequency wind speed data into separate intervals, the stochastic characteristic of the steady wind speed can be represented as a Markov process, while the high-frequency wind speed in the each interval is regarded as the disturbance input. Then, the traditional operating points of wind turbine can be divided into separate subregions correspondingly, where the model parameters and the control mode can be fixed in each mode. Then, the mixed H2/H∞ control problem is discussed for such a class of Markovian jump wind turbine working above the rated wind speed to guarantee both the disturbance rejection and the mechanical loads objectives, which can reduce the power volatility and the generator torque fluctuation of the whole transmission mechanism efficiently. Simulation results for a 2 MW wind turbine show the effectiveness of the proposed method.

Pattern, growth, and aging in aggregation kinetics of a Vicsek-like active matter model

NASA Astrophysics Data System (ADS)

Das, Subir K.

2017-01-01

Via molecular dynamics simulations, we study kinetics in a Vicsek-like phase-separating active matter model. Quantitative results, for isotropic bicontinuous pattern, are presented on the structure, growth, and aging. These are obtained via the two-point equal-time density-density correlation function, the average domain length, and the two-time density autocorrelation function. Both the correlation functions exhibit basic scaling properties, implying self-similarity in the pattern dynamics, for which the average domain size exhibits a power-law growth in time. The equal-time correlation has a short distance behavior that provides reasonable agreement between the corresponding structure factor tail and the Porod law. The autocorrelation decay is a power-law in the average domain size. Apart from these basic similarities, the overall quantitative behavior of the above-mentioned observables is found to be vastly different from those of the corresponding passive limit of the model which also undergoes phase separation. The functional forms of these have been quantified. An exceptionally rapid growth in the active system occurs due to fast coherent motion of the particles, mean-squared-displacements of which exhibit multiple scaling regimes, including a long time ballistic one.

Modeling of four-terminal solar photovoltaic systems for field application

NASA Astrophysics Data System (ADS)

Vahanka, Harikrushna; Purohit, Zeel; Tripathi, Brijesh

2018-05-01

In this article a theoretical framework for mechanically stacked four-terminal solar photovoltaic (FTSPV) system has been proposed. In a mechanical stack arrangement, a semitransparent CdTe panel has been used as a top sub-module, whereas a μc-Si solar panel has been used as bottom sub-module. Theoretical modeling has been done to analyze the physical processes in the system and to estimate reliable prediction of the performance. To incorporate the effect of material, the band gap and the absorption coefficient data for CdTe and μc-Si panels have been considered. The electrical performance of the top and bottom panels operated in a mechanical stack has been obtained experimentally for various inter-panel separations in the range of 0-3 cm. Maximum output power density has been obtained for a separation of 0.75 cm. The mean value of output power density from CdTe (top panel) has been calculated as 32.3 Wm-2 and the mean value of output power density from μc-Si, the bottom panel of four-terminal photovoltaic system has been calculated as ˜3.5 Wm-2. Results reported in this study reveal the potential of mechanically stacked four-terminal tandem solar photovoltaic system towards an energy-efficient configuration.

Determination of the optimal mesh parameters for Iguassu centrifuge flow and separation calculations

NASA Astrophysics Data System (ADS)

Romanihin, S. M.; Tronin, I. V.

2016-09-01

We present the method and the results of the determination for optimal computational mesh parameters for axisymmetric modeling of flow and separation in the Iguasu gas centrifuge. The aim of this work was to determine the mesh parameters which provide relatively low computational cost whithout loss of accuracy. We use direct search optimization algorithm to calculate optimal mesh parameters. Obtained parameters were tested by the calculation of the optimal working regime of the Iguasu GC. Separative power calculated using the optimal mesh parameters differs less than 0.5% from the result obtained on the detailed mesh. Presented method can be used to determine optimal mesh parameters of the Iguasu GC with different rotor speeds.

Kenya Promulgates a New Constitution

DTIC Science & Technology

2011-03-10

envisaged separation of powers between the three arms of government was slowly lost and power became concentrated in the Executive. The Legislative and...changes in the separation of powers between the three arms of government, major matters of citizenship, the Bill of Rights, the devolution of government

Verification of reflectance models in turbid waters

NASA Technical Reports Server (NTRS)

Tanis, F. J.; Lyzenga, D. R.

1981-01-01

Inherent optical parameters of very turbid waters were used to evaluate existing water reflectance models. Measured upwelling radiance spectra and Monte Carlo simulations of the radiative transfer equations were compared with results from models based upon two flow, quasi-single scattering, augmented isotropic scattering, and power series approximation. Each model was evaluated for three separate components of upwelling radiance: (1) direct sunlight; (2) diffuse skylight; and (3) internally reflected light. Limitations of existing water reflectance models as applied to turbid waters and possible applications to the extraction of water constituent information are discussed.

Nonequilibrium Phase Transition in a Model for Social Influence

NASA Astrophysics Data System (ADS)

Castellano, Claudio; Marsili, Matteo; Vespignani, Alessandro

2000-10-01

We present extensive numerical simulations of the Axelrod's model for social influence, aimed at understanding the formation of cultural domains. This is a nonequilibrium model with short range interactions and a remarkably rich dynamical behavior. We study the phase diagram of the model and uncover a nonequilibrium phase transition separating an ordered (culturally polarized) phase from a disordered (culturally fragmented) one. The nature of the phase transition can be continuous or discontinuous depending on the model parameters. At the transition, the size of cultural regions is power-law distributed.

Moisture Separator Reheater for NPP Turbines

NASA Astrophysics Data System (ADS)

Manabe, Jun; Kasahara, Jiro

This paper introduces the development of the current model Moisture Separator Reheater (MSR) for nuclear power plant (NPP) turbines, commercially placed in service in the period 1984-1997, focusing on the mist separation performance of the MSR along with drainage from heat exchanger tubes. A method of predicting the mist separation performance was devised first based on the observation of mist separation behaviors under an air-water test. Then the method was developed for the application to predict under the steam conditions, followed by the verification in comparison with the actual results of a steam condition test. The instability of tube drainage associated with both sub-cooling and temperature oscillation might adversely affect the seal welding of tubes to tube sheet due to thermal fatigue. The instability was measured on an existing unit to clarify behaviors and the development of a method to suppress them. Both methods were applied to newly constructed units and the effectiveness of the methods was demonstrated.

High gliding fluid power generation system with fluid component separation and multiple condensers

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

Mahmoud, Ahmad M; Lee, Jaeseon; Radcliff, Thomas D

2014-10-14

An example power generation system includes a vapor generator, a turbine, a separator and a pump. In the separator, the multiple components of the working fluid are separated from each other and sent to separate condensers. Each of the separate condensers is configured for condensing a single component of the working fluid. Once each of the components condense back into a liquid form they are recombined and exhausted to a pump that in turn drives the working fluid back to the vapor generator.

Aerodynamic Analyses and Database Development for Ares I Vehicle First Stage Separation

NASA Technical Reports Server (NTRS)

Pamadi, Bandu N.; Pei, Jing; Pinier, Jeremy T.; Holland, Scott D.; Covell, Peter F.; Klopfer, Goetz, H.

2012-01-01

This paper presents the aerodynamic analysis and database development for the first stage separation of the Ares I A106 Crew Launch Vehicle configuration. Separate databases were created for the first stage and upper stage. Each database consists of three components: isolated or free-stream coefficients, power-off proximity increments, and power-on proximity increments. The power-on database consists of three parts, all plumes firing at nominal conditions, the one booster deceleration motor out condition, and the one ullage settling motor out condition. The isolated and power-off incremental databases were developed using wind tunnel test data. The power-on proximity increments were developed using CFD solutions.

Revisiting the Legislative Veto Issue: A Recent Amendment to the Arms Export Control Act

DTIC Science & Technology

1986-01-01

Executive functions in disregard of the fundamental principle of separation of powers . [10] In the aftermath of the presidential veto, the Congress adopted...history, the Supreme Court endorsed the Constitution’s scheme for the separation of powers . Chief Justice Warren E. Burger noted that Article I of...majority. Accordingly, the drafters of Public Law 99-247 considered that the joint resolution mechanism satisfies the " separation of powers " and the

Judicial Privilege: Does It Have a Role in Military Courts-Martial

DTIC Science & Technology

1992-04-01

practitioners and judges, both military and civilian, in light of recent politicized struggles between the branches of government invoking the separation of powers doctrine...judicial branch; an act in furtherance of the doctrine of separation of powers set up by the first three articles of the Constitution.I 0 8 2. Dicta...investigators of the historical functions of the doctrine of separation of powers , and went on to declare: In recognition of the fundamental soundness of

Presidential Claims of Executive Privilege: History, Law, Practice and Recent Developments

DTIC Science & Technology

2007-07-05

assigned area of constitutional duties” and in the separation of powers .29 But although it considered a president’s communications with his close advisors...exemption serves as an important boundary marking the separation of powers . When congressional oversight “is used CRS-11 61 Smith Letter/Watt, supra n...the Executive: Hearings Before the Subcommittee on Separation of Powers of the Senate Committee on the Judiciary, 92d Cong. 1st Sess. 424 (Rehnquist

The State Secrets Privilege and Other Limits on Litigation Involving Classified Information

DTIC Science & Technology

2009-05-28

Privilege And Separation Of Powers , 75 FORDHAM L. REV. 1931, 1935 (Mar. 2007). 2 Editorial, Securing Lawsuits, WASH. POST, May 11, 2009, at A16...the Supreme Court invalidated a legislative enactment that required federal courts to reopen final decisions as a violation of the separation of powers principle...95 It might be argued that the retroactivity provision in H.R. 984 also reopens final judgments in violation of the separation of powers principle

Financial Challenges and Responsibilities in the Management of the Navy Flying Hour Program at the Squadron Level

DTIC Science & Technology

2007-12-01

first the separation of powers was designed to restrain the power of any one branch. Second was to ensure that cooperation would be necessary for...effective government (Oleszek, 1996, p. 2). Due to this separation of powers they gave “Power of the Purse” to Congress as stated in Article 1, Section

MSR performance enhancements and modifications at St. Lucie Power Plant

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

Rubano, V.F.; Ugelow, A.G.; Menocal, A.G.

1989-01-01

The St. Lucie Power Plant provides an excellent historical prospective on various moisture separator/reheater improvements. Between the two essentially identical units there is a total of 14 years of operating experience with various moisture separator/reheater configurations, with a combination of four different heat transfer surfaces and three moisture removal configurations. Through various modifications and enhancements, the performance and the reliability of the moisture separator/reheaters at the St. Lucie Power Plant and consequently the overall plant performance has been improved. This improvement has taken place over several years and involves changes in both the heat transfer and moisture removal areas. Thismore » paper provides an overview of the history and description of moisture separator/reheater modifications at the St. Lucie Power Plant with the resulting performance improvements.« less

Continuation Power Flow Analysis for PV Integration Studies at Distribution Feeders

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

Wang, Jiyu; Zhu, Xiangqi; Lubkeman, David L.

2017-10-30

This paper presents a method for conducting continuation power flow simulation on high-solar penetration distribution feeders. A load disaggregation method is developed to disaggregate the daily feeder load profiles collected in substations down to each load node, where the electricity consumption of residential houses and commercial buildings are modeled using actual data collected from single family houses and commercial buildings. This allows the modeling of power flow and voltage profile along a distribution feeder on a continuing fashion for a 24- hour period at minute-by-minute resolution. By separating the feeder into load zones based on the distance between the loadmore » node and the feeder head, we studied the impact of PV penetration on distribution grid operation in different seasons and under different weather conditions for different PV placements.« less

Separation of Powers and the Legislative Power.

ERIC Educational Resources Information Center

Rossum, Ralph A.

1986-01-01

Addresses the contribution of separation of powers and checks and balances in resolving the rival defects of democratic ineptitude and majority tyranny as the Founders framed the Constitution. Contends the Founders structured the government so that the three branches could keep each other in their proper places. Discusses Anti- Federalist…

Global performance enhancements via pedestal optimisation on ASDEX Upgrade

NASA Astrophysics Data System (ADS)

Dunne, M. G.; Frassinetti, L.; Beurskens, M. N. A.; Cavedon, M.; Fietz, S.; Fischer, R.; Giannone, L.; Huijsmans, G. T. A.; Kurzan, B.; Laggner, F.; McCarthy, P. J.; McDermott, R. M.; Tardini, G.; Viezzer, E.; Willensdorfer, M.; Wolfrum, E.; The EUROfusion MST1 Team; The ASDEX Upgrade Team

2017-02-01

Results of experimental scans of heating power, plasma shape, and nitrogen content are presented, with a focus on global performance and pedestal alteration. In detailed scans at low triangularity, it is shown that the increase in stored energy due to nitrogen seeding stems from the pedestal. It is also shown that the confinement increase is driven through the temperature pedestal at the three heating power levels studied. In a triangularity scan, an orthogonal effect of shaping and seeding is observed, where increased plasma triangularity increases the pedestal density, while impurity seeding (carbon and nitrogen) increases the pedestal temperature in addition to this effect. Modelling of these effects was also undertaken, with interpretive and predictive models being employed. The interpretive analysis shows a general agreement of the experimental pedestals in separate power, shaping, and seeding scans with peeling-ballooning theory. Predictive analysis was used to isolate the individual effects, showing that the trends of additional heating power and increased triangularity can be recoverd. However, a simple change of the effective charge in the plasma cannot explain the observed levels of confinement improvement in the present models.

Modeling of trim panels in the energy finite element analysis

NASA Astrophysics Data System (ADS)

Moravaeji, Seyed-Javid

Modeling a trim panel is divided into finding the power exchange through two different paths: (i) the connection of the outer and inner panels (ii) through the layers directly. The vibrational power exchanged through the mounts is modeled as the connection of two parallel plates connected via a beam. Wave matrices representing plates and beams are derived separately; then a matrix method is proposed to solve for the wave amplitudes and hence the vibrational power exchange between the plates accordingly. A closed form formula for the case of connection of two identical plates is derived. For the power transmission loss directly through the layers, first transfer matrices representing layers made of different materials is considered. New matrices for a porous layer are derived. A method of finding the layered structure transfer matrix is proposed. It is concluded that in general a single isotropic layer cannot replace a structure accurately. Finally, on the basis of an equivalent transfer matrix, an optimization process for is proposed to replace the panel by a suitable set of layers.

Evaluation of pressure and thermal data from a wind tunnel test of a large-scale, powered, STOL fighter model

NASA Technical Reports Server (NTRS)

Howell, G. A.; Crosthwait, E. L.; Witte, M. C.

1981-01-01

A STOL fighter model employing the vectored-engine-over wing concept was tested at low speeds in the NASA/Ames 40 by 80-foot wind tunnel. The model, approximately 0.75 scale of an operational fighter, was powered by two General Electric J-97 turbojet engines. Limited pressure and thermal instrumentation were provided to measure power effects (chordwise and spanwise blowing) and control-surface-deflection effects. An indepth study of the pressure and temperature data revealed many flow field features - the foremost being wing and canard leading-edge vortices. These vortices delineated regions of attached and separated flow, and their movements were often keys to an understanding of flow field changes caused by power and control-surface variations. Chordwise blowing increased wing lift and caused a modest aft shift in the center of pressure. The induced effects of chordwise blowing extended forward to the canard and significantly increased the canard lift when the surface was stalled. Spanwise blowing effectively enhanced the wing leading-edge vortex, thereby increasing lift and causing a forward shift in the center of pressure.

Tube failures in moisture separator-reheater tube bundles due to restrained thermal expansion

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

Heilker, W.J.; Cassell, D.S.

1983-01-01

In a nuclear power plant, moisture separator-reheater components (MSRs) are used to dry and superheat the exhaust steam from the high pressure turbine before admitting this steam to the low pressure turbines. MSRs have experienced numerous problems which have caused loss of plant thermal efficiency, poor unit availability and high maintenance costs. The most serious problem has been the progressive failure of the U-tubes, which has necessitated replacement of MSR tube bundles at several plants. This paper presents an explanation of the failure mode and identifies critical operational and geometric parameters as to their respective roles in the process. Detailedmore » thermal-hydraulic analytic modeling enables the calculation of tube wall temperatures along the length of each tube for selected power levels. These temperature data are input to finite element models of the tube bundle which yield interactive displacements, rotations and stresses. The results of these studies provide the rational basis for the tube failure mechanism, which is supported by data acquired from inspection of in-service MSRs.« less

Optical Variability Signatures from Massive Black Hole Binaries

NASA Astrophysics Data System (ADS)

Kasliwal, Vishal P.; Frank, Koby Alexander; Lidz, Adam

2017-01-01

The hierarchical merging of dark matter halos and their associated galaxies should lead to a population of supermassive black hole binaries (MBHBs). We consider plausible optical variability signatures from MBHBs at sub-parsec separations and search for these using data from the Catalina Real-Time Transient Survey (CRTS). Specifically, we model the impact of relativistic Doppler beaming on the accretion disk emission from the less massive, secondary black hole. We explore whether this Doppler modulation may be separated from other sources of stochastic variability in the accretion flow around the MBHBs, which we describe as a damped random walk (DRW). In the simple case of a circular orbit, relativistic beaming leads to a series of broad peaks — located at multiples of the orbital frequency — in the fluctuation power spectrum. We extend our analysis to the case of elliptical orbits and discuss the effect of beaming on the flux power spectrum and auto-correlation function using simulations. We present a code to model an observed light curve as a stochastic DRW-type time series modulated by relativistic beaming and apply the code to CRTS data.

Minimal universal quantum heat machine.

PubMed

Gelbwaser-Klimovsky, D; Alicki, R; Kurizki, G

2013-01-01

In traditional thermodynamics the Carnot cycle yields the ideal performance bound of heat engines and refrigerators. We propose and analyze a minimal model of a heat machine that can play a similar role in quantum regimes. The minimal model consists of a single two-level system with periodically modulated energy splitting that is permanently, weakly, coupled to two spectrally separated heat baths at different temperatures. The equation of motion allows us to compute the stationary power and heat currents in the machine consistent with the second law of thermodynamics. This dual-purpose machine can act as either an engine or a refrigerator (heat pump) depending on the modulation rate. In both modes of operation, the maximal Carnot efficiency is reached at zero power. We study the conditions for finite-time optimal performance for several variants of the model. Possible realizations of the model are discussed.

Big data mining powers fungal research: recent advances in fission yeast systems biology approaches.

PubMed

Wang, Zhe

2017-06-01

Biology research has entered into big data era. Systems biology approaches therefore become the powerful tools to obtain the whole landscape of how cell separate, grow, and resist the stresses. Fission yeast Schizosaccharomyces pombe is wonderful unicellular eukaryote model, especially studying its division and metabolism can facilitate to understanding the molecular mechanism of cancer and discovering anticancer agents. In this perspective, we discuss the recent advanced fission yeast systems biology tools, mainly focus on metabolomics profiling and metabolic modeling, protein-protein interactome and genetic interaction network, DNA sequencing and applications, and high-throughput phenotypic screening. We therefore hope this review can be useful for interested fungal researchers as well as bioformaticians.

Improving Communication Between Senior Air Force Leadership and Troops in the Field

DTIC Science & Technology

2002-04-01

Leadership................................................................................................12 Constitutional Separation of Powers .....................................................................12...transform its organizational characteristics. Constitutional Separation of Powers The Department of Defense falls within the executive branch of the

Two-locus diseas models with two marker loci: The power of affected-sib-pair tests

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

Knapp, M.; Seuchter, S.A.; Bauer, M.P.

1994-11-01

Recently, Schork et al. found that two-trait-locus, two-marker-locus (parametric) linkage analysis can provide substantially more linkage information than can standard one-trait-locus, one-marker-locus methods. However, because of the increased burden of computation, Schork et al. do not expect that their approach will be applied in an initial genome scan. Further, the specification of a suitable two-locus segregation model can be crucial. Affected-sib-pair tests are computationally simple and do not require an explicit specification of the disease model. In the past, however, these tests mainly have been applied to data with a single marker locus. Here, we consider sib-pair tests that makemore » it possible to analyze simultaneously two marker loci. The power of these tests is investigated for different (epistatic and heterogeneous) two-trait-locus models, each trait locus being linked to one of the marker loci. We compare these tests both with the test that is optimal for a certain model and with the strategy that analyzes each marker locus separately. The results indicate that a straightforward extension of the well-known mean test for two marker loci can be much more powerful than single-marker-locus analysis and that its power is only slightly inferior to the power of the optimal test. 21 refs., 5 figs., 2 tabs.« less

Anomalous diffusion in neutral evolution of model proteins.

PubMed

Nelson, Erik D; Grishin, Nick V

2015-06-01

Protein evolution is frequently explored using minimalist polymer models, however, little attention has been given to the problem of structural drift, or diffusion. Here, we study neutral evolution of small protein motifs using an off-lattice heteropolymer model in which individual monomers interact as low-resolution amino acids. In contrast to most earlier models, both the length and folded structure of the polymers are permitted to change. To describe structural change, we compute the mean-square distance (MSD) between monomers in homologous folds separated by n neutral mutations. We find that structural change is episodic, and, averaged over lineages (for example, those extending from a single sequence), exhibits a power-law dependence on n. We show that this exponent depends on the alignment method used, and we analyze the distribution of waiting times between neutral mutations. The latter are more disperse than for models required to maintain a specific fold, but exhibit a similar power-law tail.

Anomalous diffusion in neutral evolution of model proteins

NASA Astrophysics Data System (ADS)

Nelson, Erik D.; Grishin, Nick V.

2015-06-01

Protein evolution is frequently explored using minimalist polymer models, however, little attention has been given to the problem of structural drift, or diffusion. Here, we study neutral evolution of small protein motifs using an off-lattice heteropolymer model in which individual monomers interact as low-resolution amino acids. In contrast to most earlier models, both the length and folded structure of the polymers are permitted to change. To describe structural change, we compute the mean-square distance (MSD) between monomers in homologous folds separated by n neutral mutations. We find that structural change is episodic, and, averaged over lineages (for example, those extending from a single sequence), exhibits a power-law dependence on n . We show that this exponent depends on the alignment method used, and we analyze the distribution of waiting times between neutral mutations. The latter are more disperse than for models required to maintain a specific fold, but exhibit a similar power-law tail.

NASA Tech Briefs, January 2010

NASA Technical Reports Server (NTRS)

2010-01-01

Topics covered include: Cryogenic Flow Sensor; Multi-Sensor Mud Detection; Gas Flow Detection System; Mapping Capacitive Coupling Among Pixels in a Sensor Array; Fiber-Based Laser Transmitter for Oxygen A-Band Spectroscopy and Remote Sensing; Low-Profile, Dual-Wavelength, Dual-Polarized Antenna; Time-Separating Heating and Sensor Functions of Thermistors in Precision Thermal Control Applications; Cellular Reflectarray Antenna; A One-Dimensional Synthetic-Aperture Microwave Radiometer; Electrical Switching of Perovskite Thin-Film Resistors; Two-Dimensional Synthetic-Aperture Radiometer; Ethernet-Enabled Power and Communication Module for Embedded Processors; Electrically Variable Resistive Memory Devices; Improved Attachment in a Hybrid Inflatable Pressure Vessel; Electrostatic Separator for Beneficiation of Lunar Soil; Amorphous Rover; Space-Frame Antenna; Gear-Driven Turnbuckle Actuator; In-Situ Focusing Inside a Thermal Vacuum Chamber; Space-Frame Lunar Lander; Wider-Opening Dewar Flasks for Cryogenic Storage; Silicon Oxycarbide Aerogels for High-Temperature Thermal Insulation; Supercapacitor Electrolyte Solvents with Liquid Range Below -80 C; Designs and Materials for Better Coronagraph Occulting Masks; Fuel-Cell-Powered Vehicle with Hybrid Power Management; Fine-Water-Mist Multiple-Orientation-Discharge Fire Extinguisher; Fuel-Cell Water Separator; Turbulence and the Stabilization Principle; Improved Cloud Condensation Nucleus Spectrometer; Better Modeling of Electrostatic Discharge in an Insulator; Sub-Aperture Interferometers; Terahertz Mapping of Microstructure and Thickness Variations; Multiparallel Three-Dimensional Optical Microscopy; Stabilization of Phase of a Sinusoidal Signal Transmitted Over Optical Fiber; Vacuum-Compatible Wideband White Light and Laser Combiner Source System; Optical Tapers as White-Light WGM Resonators; EPR Imaging at a Few Megahertz Using SQUID Detectors; Reducing Field Distortion in Magnetic Resonance Imaging; Fluorogenic Cell-Based Biosensors for Monitoring Microbes; A Constant-Force Resistive Exercise Unit; GUI to Facilitate Research on Biological Damage from Radiation; On-Demand Urine Analyzer; More-Realistic Digital Modeling of a Human Body; and Advanced Liquid-Cooling Garment Using Highly Thermally Conductive Sheets.

The Constitutional Aspects of the War Powers Resolution of November 7, 1973.

DTIC Science & Technology

legislation is examined in light of the constitutional separation of powers between the legislative and executive branch of government and its impact on...the executive. This essay contains an examination of the historical constitutional cases and the constitutional convention discussions on the separation of powers to ’make war.’ (Author)

Separation of Powers.

ERIC Educational Resources Information Center

Bill of Rights in Action, 1987

1987-01-01

The dimensions of the separation of powers principle are explored through three lessons in the subject areas of U.S. history, U.S. government, and world history. In 1748, a French nobleman, Baron de Montesquieu, wrote a book called "The Spirit of the Laws," in which he argued that there could be no liberty when all government power was…

Impinging jet separators for liquid metal magnetohydrodynamic power cycles

NASA Technical Reports Server (NTRS)

Bogdanoff, D. W.

1973-01-01

In many liquid metal MHD power, cycles, it is necessary to separate the phases of a high-speed liquid-gas flow. The usual method is to impinge the jet at a glancing angle against a solid surface. These surface separators achieve good separation of the two phases at a cost of a large velocity loss due to friction at the separator surface. This report deals with attempts to greatly reduce the friction loss by impinging two jets against each other. In the crude impinging jet separators tested to date, friction losses were greatly reduced, but the separation of the two phases was found to be much poorer than that achievable with surface separators. Analyses are presented which show many lines of attack (mainly changes in separator geometry) which should yield much better separation for impinging jet separators).

Biomass to Liquid Fuels and Electrical Power

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

Taylor, Steven; McDonald, Timothy; Gallagher, Thomas

This research program provided data on immediate applicability of forest biomass production and logistics models. Also, the research further developed and optimized fractionation techniques that can be used to separate biomass feedstocks into their basic chemical constituents. Finally, additional research established systematic techniques to determine economically feasible technologies for production of biomass-derived synthesis gases that will be used for clean, renewable power generation and for production of liquid transportation fuels. Moreover, this research program continued our efforts to educate the next generation of engineers and scientists needed to implement these technologies.

Rapid ISS Power Availability Simulator

NASA Technical Reports Server (NTRS)

Downing, Nicholas

2011-01-01

The ISS (International Space Station) Power Resource Officers (PROs) needed a tool to automate the calculation of thousands of ISS power availability simulations used to generate power constraint matrices. Each matrix contains 864 cells, and each cell represents a single power simulation that must be run. The tools available to the flight controllers were very operator intensive and not conducive to rapidly running the thousands of simulations necessary to generate the power constraint data. SOLAR is a Java-based tool that leverages commercial-off-the-shelf software (Satellite Toolkit) and an existing in-house ISS EPS model (SPEED) to rapidly perform thousands of power availability simulations. SOLAR has a very modular architecture and consists of a series of plug-ins that are loosely coupled. The modular architecture of the software allows for the easy replacement of the ISS power system model simulator, re-use of the Satellite Toolkit integration code, and separation of the user interface from the core logic. Satellite Toolkit (STK) is used to generate ISS eclipse and insulation times, solar beta angle, position of the solar arrays over time, and the amount of shadowing on the solar arrays, which is then provided to SPEED to calculate power generation forecasts. The power planning turn-around time is reduced from three months to two weeks (83-percent decrease) using SOLAR, and the amount of PRO power planning support effort is reduced by an estimated 30 percent.

Intrinsic and environmental effects on the interference properties of a high-performance quantum dot single-photon source

NASA Astrophysics Data System (ADS)

Gerhardt, Stefan; Iles-Smith, Jake; McCutcheon, Dara P. S.; He, Yu-Ming; Unsleber, Sebastian; Betzold, Simon; Gregersen, Niels; Mørk, Jesper; Höfling, Sven; Schneider, Christian

2018-05-01

We report a joint experimental and theoretical study of the interference properties of a single-photon source based on a In(Ga)As quantum dot embedded in a quasiplanar GaAs microcavity. Using resonant laser excitation with a pulse separation of 2 ns, we find near-perfect interference of the emitted photons, and a corresponding indistinguishability of I =(99.6 -1.4+0.4)% . For larger pulse separations, quasiresonant excitation conditions, increasing pump power, or with increasing temperature, the interference contrast is progressively and notably reduced. We present a systematic study of the relevant dephasing mechanisms and explain our results in the framework of a microscopic model of our system. For strictly resonant excitation, we show that photon indistinguishability is independent of pump power, but strongly influenced by virtual phonon-assisted processes which are not evident in excitonic Rabi oscillations.

Cash income, intrahousehold cooperative conflict, and child health in central Mozambique.

PubMed

Pfeiffer, James

2003-01-01

This study presents qualitative data on individual cash income generation and intrahousehold bargaining in a sample of 100 households in central Mozambique. It is now recognized that intrahousehold resource allocation patterns can be critical determinants of children's health in the developing world. Recently developed "bargaining-power" models suggest that individual incomes are often not pooled in households and that decisions are the result of a bargaining process that involves cooperation and conflict between men and women. Women's income, many believe, is more often spent on child welfare. Development projects should target benefits to women for greater impact on child health. Some argue that households consist of separate, gendered spheres of economic responsibility that intersect through a "conjugal contract" that defines the terms of cooperation. The findings here support the "separate-spheres" depiction of the household and reveal women's subordinated position in the external cash economy, which undermines their intrahousehold bargaining power.

Redundant speed control for brushless Hall effect motor

NASA Technical Reports Server (NTRS)

Nola, F. J. (Inventor)

1973-01-01

A speed control system for a brushless Hall effect device equipped direct current (D.C.) motor is described. Separate windings of the motor are powered by separate speed responsive power sources. A change in speed, upward or downward, because of the failure of a component of one of the power sources results in a corrective signal being generated in the other power source to supply an appropriate power level and polarity to one winding to cause the motor to be corrected in speed.

Charge carrier concentration dependence of encounter-limited bimolecular recombination in phase-separated organic semiconductor blends

NASA Astrophysics Data System (ADS)

Heiber, Michael C.; Nguyen, Thuc-Quyen; Deibel, Carsten

2016-05-01

Understanding how the complex intermolecular configurations and nanostructure present in organic semiconductor donor-acceptor blends impacts charge carrier motion, interactions, and recombination behavior is a critical fundamental issue with a particularly major impact on organic photovoltaic applications. In this study, kinetic Monte Carlo (KMC) simulations are used to numerically quantify the complex bimolecular charge carrier recombination behavior in idealized phase-separated blends. Recent KMC simulations have identified how the encounter-limited bimolecular recombination rate in these blends deviates from the often used Langevin model and have been used to construct the new power mean mobility model. Here, we make a challenging but crucial expansion to this work by determining the charge carrier concentration dependence of the encounter-limited bimolecular recombination coefficient. In doing so, we find that an accurate treatment of the long-range electrostatic interactions between charge carriers is critical, and we further argue that many previous KMC simulation studies have used a Coulomb cutoff radius that is too small, which causes a significant overestimation of the recombination rate. To shed more light on this issue, we determine the minimum cutoff radius required to reach an accuracy of less than ±10 % as a function of the domain size and the charge carrier concentration and then use this knowledge to accurately quantify the charge carrier concentration dependence of the recombination rate. Using these rigorous methods, we finally show that the parameters of the power mean mobility model are determined by a newly identified dimensionless ratio of the domain size to the average charge carrier separation distance.

The Separation of Blood Components Using Standing Surface Acoustic Waves (SSAWs) Microfluidic Devices: Analysis and Simulation.

PubMed

Soliman, Ahmed M; Eldosoky, Mohamed A; Taha, Taha E

2017-03-29

The separation of blood components (WBCs, RBCs, and platelets) is important for medical applications. Recently, standing surface acoustic wave (SSAW) microfluidic devices are used for the separation of particles. In this paper, the design analysis of SSAW microfluidics is presented. Also, the analysis of SSAW force with Rayleigh angle effect and its attenuation in liquid-loaded substrate, viscous drag force, hydrodynamic force, and diffusion force are explained and analyzed. The analyses are provided for selecting the piezoelectric material, width of the main microchannel, working area of SAW, wavelength, minimum input power required for the separation process, and widths of outlet collecting microchannels. The design analysis of SSAW microfluidics is provided for determining the minimum input power required for the separation process with appropriated the displacement contrast of the particles.The analyses are applied for simulation the separation of blood components. The piezoelectric material, width of the main microchannel, working area of SAW, wavelength, and minimum input power required for the separation process are selected as LiNbO₃, 120 μm, 1.08 mm², 300 μm, 371 mW. The results are compared to other published results. The results of these simulations achieve minimum power consumption, less complicated setup, and high collecting efficiency. All simulation programs are built by MATLAB.

The Separation of Blood Components Using Standing Surface Acoustic Waves (SSAWs) Microfluidic Devices: Analysis and Simulation

PubMed Central

Soliman, Ahmed M.; Eldosoky, Mohamed A.; Taha, Taha E.

2017-01-01

The separation of blood components (WBCs, RBCs, and platelets) is important for medical applications. Recently, standing surface acoustic wave (SSAW) microfluidic devices are used for the separation of particles. In this paper, the design analysis of SSAW microfluidics is presented. Also, the analysis of SSAW force with Rayleigh angle effect and its attenuation in liquid-loaded substrate, viscous drag force, hydrodynamic force, and diffusion force are explained and analyzed. The analyses are provided for selecting the piezoelectric material, width of the main microchannel, working area of SAW, wavelength, minimum input power required for the separation process, and widths of outlet collecting microchannels. The design analysis of SSAW microfluidics is provided for determining the minimum input power required for the separation process with appropriated the displacement contrast of the particles.The analyses are applied for simulation the separation of blood components. The piezoelectric material, width of the main microchannel, working area of SAW, wavelength, and minimum input power required for the separation process are selected as LiNbO3, 120 μm, 1.08 mm2, 300 μm, 371 mW. The results are compared to other published results. The results of these simulations achieve minimum power consumption, less complicated setup, and high collecting efficiency. All simulation programs are built by MATLAB. PMID:28952506

Uncertainty Assessments of 2D and Axisymmetric Hypersonic Shock Wave - Turbulent Boundary Layer Interaction Simulations at Compression Corners

NASA Technical Reports Server (NTRS)

Gnoffo, Peter A.; Berry, Scott A.; VanNorman, John W.

2011-01-01

This paper is one of a series of five papers in a special session organized by the NASA Fundamental Aeronautics Program that addresses uncertainty assessments for CFD simulations in hypersonic flow. Simulations of a shock emanating from a compression corner and interacting with a fully developed turbulent boundary layer are evaluated herein. Mission relevant conditions at Mach 7 and Mach 14 are defined for a pre-compression ramp of a scramjet powered vehicle. Three compression angles are defined, the smallest to avoid separation losses and the largest to force a separated flow engaging more complicated flow physics. The Baldwin-Lomax and the Cebeci-Smith algebraic models, the one-equation Spalart-Allmaras model with the Catrix-Aupoix compressibility modification and two-equation models including Menter SST, Wilcox k-omega 98, and Wilcox k-omega 06 turbulence models are evaluated. Each model is fully defined herein to preclude any ambiguity regarding model implementation. Comparisons are made to existing experimental data and Van Driest theory to provide preliminary assessment of model form uncertainty. A set of coarse grained uncertainty metrics are defined to capture essential differences among turbulence models. Except for the inability of algebraic models to converge for some separated flows there is no clearly superior model as judged by these metrics. A preliminary metric for the numerical component of uncertainty in shock-turbulent-boundary-layer interactions at compression corners sufficiently steep to cause separation is defined as 55%. This value is a median of differences with experimental data averaged for peak pressure and heating and for extent of separation captured in new, grid-converged solutions presented here. This value is consistent with existing results in a literature review of hypersonic shock-turbulent-boundary-layer interactions by Roy and Blottner and with more recent computations of MacLean.

Co-Clustering by Bipartite Spectral Graph Partitioning for Out-of-Tutor Prediction

ERIC Educational Resources Information Center

Trivedi, Shubhendu; Pardos, Zachary A.; Sarkozy, Gabor N.; Heffernan, Neil T.

2012-01-01

Learning a more distributed representation of the input feature space is a powerful method to boost the performance of a given predictor. Often this is accomplished by partitioning the data into homogeneous groups by clustering so that separate models could be trained on each cluster. Intuitively each such predictor is a better representative of…

Carter, Reagan, and Congress: The Changing Dynamics of Security Assistance and Arms Sales

DTIC Science & Technology

1991-01-01

only enumerated power given to the President in the Constitution is the title of Commander-in-Chief of the armed forces. As part of the separation of powers , Congress...constitutional separation of powers and the law was struck down on the grounds that this type of resolution fails the test of presentment to the

Statistical simulations of the dust foreground to cosmic microwave background polarization

NASA Astrophysics Data System (ADS)

Vansyngel, F.; Boulanger, F.; Ghosh, T.; Wandelt, B.; Aumont, J.; Bracco, A.; Levrier, F.; Martin, P. G.; Montier, L.

2017-07-01

The characterization of the dust polarization foreground to the cosmic microwave background (CMB) is a necessary step toward the detection of the B-mode signal associated with primordial gravitational waves. We present a method to simulate maps of polarized dust emission on the sphere that is similar to the approach used for CMB anisotropies. This method builds on the understanding of Galactic polarization stemming from the analysis of Planck data. It relates the dust polarization sky to the structure of the Galactic magnetic field and its coupling with interstellar matter and turbulence. The Galactic magnetic field is modeled as a superposition of a mean uniform field and a Gaussian random (turbulent) component with a power-law power spectrum of exponent αM. The integration along the line of sight carried out to compute Stokes maps is approximated by a sum over a small number of emitting layers with different realizations of the random component of the magnetic field. The model parameters are constrained to fit the power spectra of dust polarization EE, BB, and TE measured using Planck data. We find that the slopes of the E and B power spectra of dust polarization are matched for αM = -2.5, an exponent close to that measured for total dust intensity but larger than the Kolmogorov exponent - 11/3. The model allows us to compute multiple realizations of the Stokes Q and U maps for different realizations of the random component of the magnetic field, and to quantify the variance of dust polarization spectra for any given sky area outside of the Galactic plane. The simulations reproduce the scaling relation between the dust polarization power and the mean total dust intensity including the observed dispersion around the mean relation. We also propose a method to carry out multifrequency simulations, including the decorrelation measured recently by Planck, using a given covariance matrix of the polarization maps. These simulations are well suited to optimize component separation methods and to quantify the confidence with which the dust and CMB B-modes can be separated in present and future experiments. We also provide an astrophysical perspective on our phenomenological modeling of the dust polarization spectra.

Separation of Electric Fields Into Potential and Inductive Parts, and Implications for Radial Diffusion

NASA Astrophysics Data System (ADS)

Chan, A. A.; Ilie, R.; Elkington, S. R.; Albert, J.; Huie, W.

2017-12-01

It has been traditional to separate radiation belt radial-diffusion coefficients into two contributions: an "electrostatic" diffusion coefficient, which is assumed to be due to a potential (non-inductive) electric field, and an "electromagnetic" diffusion coefficient , which is assumed to be due to the combined effect of an inductive electric field and the corresponding time-dependent magnetic field. One difficulty in implementing this separation when using magnetospheric fields obtained from measurements, or from MHD simulations, is that only the total electric field is given; the separation of the electric field into potential and inductive parts is not readily available. In this work we separate the electric field using a numerical method based on the Helmholtz decomposition of the total motional electric field calculated by the BATS-R-US MHD code. The inner boundary for the electric potential is based on the Ridley Ionospheric Model solution and we assume floating boundary conditions in the solar wind. Using different idealized solar wind drivers, including a solar wind density that is oscillating at a single frequency or with a broad spectrum of frequencies, we calculate potential and inductive electric fields, electric and magnetic power spectral densities, and corresponding radial diffusion coefficients. Simulations driven by idealized solar wind conditions show a clear separation of the potential and inductive contributions to the power spectral densities and diffusion coefficients. Simulations with more realistic solar wind drivers are underway to better assess the use of electrostatic and electromagnetic diffusion coefficients in understanding ULF wave-particle interactions in Earth's radiation belts.

Preliminary SP-100/Stirling Heat Exchanger Designs

NASA Astrophysics Data System (ADS)

Schmitz, Paul; Tower, Leonard; Dawson, Ronald; Blue, Brain; Dunn, Pat

1994-07-01

Analytic modeling of several heat exchanger concepts to couple the SP-100 nuclear reactor primary lithium loop and the Space Stirling Power Convertor(SSPC)was performed. Four 25 kWe SSPC's are used to produce the required 100 kW of electrical power. This design work focused on the interface between a single SSPC and the primary lithium loop. Manifolding to separate and collect the four channel flow was not modeled. This work modeled two separate types of heat exchanger interfaces (conductive coupling and radiative coupling) to explore their relative advantages and disadvantages. The minimum mass design of the conductively coupled concepts was 18 kg or 0.73 kg/kWe for a single 25 kWe convertor. The minimum mass radiatively coupled concept was 41 kg or 1.64 kg/kWe. The direct conduction heat exchanger provides a lighter weight system because of its ability to operate the Stirling convertor evaporator at higher heat fluxes than those attainable by the radiatively coupled systems. Additionally the conductively coupled concepts had relatively small volumes and provide potentially simpler assembly. Their disadvantages were the tight tolerances and material joining problems associated with this refractory to superalloy interface. The advantages of the radiatively coupled designs were the minimal material interface problems.

Preliminary SP-100/Stirling heat exchanger designs

NASA Astrophysics Data System (ADS)

Schmitz, Paul; Tower, Leonard; Dawson, Ronald; Blue, Brian; Dunn, Pat

1993-12-01

Analytic modeling of several heat exchanger concepts to couple the SP-100 nuclear reactor primary lithium loop and the Space Stirling Power Convertor (SSPC) was performed. Four 25 kWe SSPC's are used to produce the required 100 kW of electrical power. This design work focused on the interface between a single SSPC and the primary lithium loop. Manifolding to separate and collect the four channel flow was not modeled. This work modeled two separate types of heat exchanger interfaces (conductive coupling and radiative coupling) to explore their relative advantages and disadvantages. The minimum mass design of the conductively coupled concepts was 18 kg or 0.73 kg/kWe for a single 25 kWe convertor. The minimum mass radiatively coupled concept was 41 kg or 1.64 kg/kWe. The direct conduction heat exchanger provides a lighter weight system because of its ability to operate the Stirling convertor evaporator at higher heat fluxes than those attainable by the radiatively coupled systems. Additionally the conductively coupled concepts had relatively small volumes and provide potentially simpler assembly. Their disadvantages were the tight tolerances and material joining problems associated with this refractory to superalloy interface. The advantages of the radiatively coupled designs were the minimal material interface problems.

Preliminary SP-100/Stirling heat exchanger designs

NASA Technical Reports Server (NTRS)

Schmitz, Paul; Tower, Leonard; Dawson, Ronald; Blue, Brian; Dunn, Pat

1993-01-01

Analytic modeling of several heat exchanger concepts to couple the SP-100 nuclear reactor primary lithium loop and the Space Stirling Power Convertor (SSPC) was performed. Four 25 kWe SSPC's are used to produce the required 100 kW of electrical power. This design work focused on the interface between a single SSPC and the primary lithium loop. Manifolding to separate and collect the four channel flow was not modeled. This work modeled two separate types of heat exchanger interfaces (conductive coupling and radiative coupling) to explore their relative advantages and disadvantages. The minimum mass design of the conductively coupled concepts was 18 kg or 0.73 kg/kWe for a single 25 kWe convertor. The minimum mass radiatively coupled concept was 41 kg or 1.64 kg/kWe. The direct conduction heat exchanger provides a lighter weight system because of its ability to operate the Stirling convertor evaporator at higher heat fluxes than those attainable by the radiatively coupled systems. Additionally the conductively coupled concepts had relatively small volumes and provide potentially simpler assembly. Their disadvantages were the tight tolerances and material joining problems associated with this refractory to superalloy interface. The advantages of the radiatively coupled designs were the minimal material interface problems.

Determinants of U.S. Prescription Drug Utilization using County Level Data.

PubMed

Nianogo, Thierry; Okunade, Albert; Fofana, Demba; Chen, Weiwei

2016-05-01

Prescription drugs are the third largest component of U.S. healthcare expenditures. The 2006 Medicare Part D and the 2010 Affordable Care Act are catalysts for further growths in utilization becuase of insurance expansion effects. This research investigating the determinants of prescription drug utilization is timely, methodologically novel, and policy relevant. Differences in population health status, access to care, socioeconomics, demographics, and variations in per capita number of scripts filled at retail pharmacies across the U.S.A. justify fitting separate econometric models to county data of the states partitioned into low, medium, and high prescription drug users. Given the skewed distribution of per capita number of filled prescriptions (response variable), we fit the variance stabilizing Box-Cox power transformation regression models to 2011 county level data for investigating the correlates of prescription drug utilization separately for low, medium, and high utilization states. Maximum likelihood regression parameter estimates, including the optimal Box-Cox λ power transformations, differ across high (λ = 0.214), medium (λ = 0.942), and low (λ = 0.302) prescription drug utilization models. The estimated income elasticities of -0.634, 0.031, and -0.532 in high, medium, and low utilization models suggest that the economic behavior of prescriptions is not invariant across different utilization levels. Copyright © 2015 John Wiley & Sons, Ltd.

Transverse Dimensions of Chorus in the Source Region

NASA Technical Reports Server (NTRS)

Santolik, O.; Gurnett, D. A.

2003-01-01

We report measurement of whistler-mode chorus by the four Cluster spacecraft at close separations. We focus our analysis on the generation region close to the magnetic equatorial plane at a radial distance of 4.4 Earth's radii. We use both linear and rank correlation analysis to define perpendicular dimensions of the sources of chorus elements below one half of the electron cyclotron frequency. Correlation is significant throughout the range of separation distances of 60-260 km parallel to the field line and 7-100 km in the perpendicular plane. At these scales, the correlation coefficient is independent for parallel separations, and decreases with perpendicular separation. The observations are consistent with a statistical model of the source region assuming individual sources as gaussian peaks of radiated power with a common half-width of 35 km perpendicular to the magnetic field. This characteristic scale is comparable to the wavelength of observed waves.

FEM numerical model study of heating in magnetic nanoparticles

NASA Astrophysics Data System (ADS)

Pearce, John A.; Cook, Jason R.; Hoopes, P. Jack; Giustini, Andrew

2011-03-01

Electromagnetic heating of nanoparticles is complicated by the extremely short thermal relaxation time constants and difficulty of coupling sufficient power into the particles to achieve desired temperatures. Magnetic field heating by the hysteresis loop mechanism at frequencies between about 100 and 300 kHz has proven to be an effective mechanism in magnetic nanoparticles. Experiments at 2.45 GHz show that Fe3O4 magnetite nanoparticle dispersions in the range of 1012 to 1013 NP/mL also heat substantially at this frequency. An FEM numerical model study was undertaken to estimate the order of magnitude of volume power density, Qgen (W m-3) required to achieve significant heating in evenly dispersed and aggregated clusters of nanoparticles. The FEM models were computed using Comsol Multiphysics; consequently the models were confined to continuum formulations and did not include film nano-dimension heat transfer effects at the nanoparticle surface. As an example, the models indicate that for a single 36 nm diameter particle at an equivalent dispersion of 1013 NP/mL located within one control volume (1.0 x 10-19 m3) of a capillary vessel a power density in the neighborhood of 1017 (W m-3) is required to achieve a steady state particle temperature of 52°C - the total power coupled to the particle is 2.44 μW. As a uniformly distributed particle cluster moves farther from the capillary the required power density decreases markedly. Finally, the tendency for particles in vivo to cluster together at separation distances much less than those of the uniform distribution further reduces the required power density.

Modeling the expenditure and reconstitution of work capacity above critical power.

PubMed

Skiba, Philip Friere; Chidnok, Weerapong; Vanhatalo, Anni; Jones, Andrew M

2012-08-01

The critical power (CP) model includes two constants: the CP and the W' [P = (W' / t) + CP]. The W' is the finite work capacity available above CP. Power output above CP results in depletion of the W' complete depletion of the W' results in exhaustion. Monitoring the W' may be valuable to athletes during training and competition. Our purpose was to develop a function describing the dynamic state of the W' during intermittent exercise. After determination of V˙O(2max), CP, and W', seven subjects completed four separate exercise tests on a cycle ergometer on different days. Each protocol comprised a set of intervals: 60 s at a severe power output, followed by 30-s recovery at a lower prescribed power output. The intervals were repeated until exhaustion. These data were entered into a continuous equation predicting balance of W' remaining, assuming exponential reconstitution of the W'. The time constant was varied by an iterative process until the remaining modeled W' = 0 at the point of exhaustion. The time constants of W' recharge were negatively correlated with the difference between sub-CP recovery power and CP. The relationship was best fit by an exponential (r = 0.77). The model-predicted W' balance correlated with the temporal course of the rise in V˙O(2) (r = 0.82-0.96). The model accurately predicted exhaustion of the W' in a competitive cyclist during a road race. We have developed a function to track the dynamic state of the W' during intermittent exercise. This may have important implications for the planning and real-time monitoring of athletic performance.

Theoretical analysis of microwave propagation

NASA Astrophysics Data System (ADS)

Parl, S.; Malaga, A.

1984-04-01

This report documents a comprehensive investigation of microwave propagation. The structure of line-of-sight multipath is determined and the impact on practical diversity is discussed. A new model of diffraction propagation for multiple rounded obstacles is developed. A troposcatter model valid at microwave frequencies is described. New results for the power impulse response, and the delay spread and Doppler spread are developed. A 2-component model separating large and small scale scatter effects is proposed. The prediction techniques for diffraction and troposcatter have been implemented in a computer program intended as a tool to analyze propagation experiments.

Visual attention: low-level and high-level viewpoints

NASA Astrophysics Data System (ADS)

Stentiford, Fred W. M.

2012-06-01

This paper provides a brief outline of the approaches to modeling human visual attention. Bottom-up and top-down mechanisms are described together with some of the problems that they face. It has been suggested in brain science that memory functions by trading measurement precision for associative power; sensory inputs from the environment are never identical on separate occasions, but the associations with memory compensate for the differences. A graphical representation for image similarity is described that relies on the size of maximally associative structures (cliques) that are found to reflect between pairs of images. This is applied to the recognition of movie posters, the location and recognition of characters, and the recognition of faces. The similarity mechanism is shown to model popout effects when constraints are placed on the physical separation of pixels that correspond to nodes in the maximal cliques. The effect extends to modeling human visual behaviour on the Poggendorff illusion.

An architecture for object-oriented intelligent control of power systems in space

NASA Technical Reports Server (NTRS)

Holmquist, Sven G.; Jayaram, Prakash; Jansen, Ben H.

1993-01-01

A control system for autonomous distribution and control of electrical power during space missions is being developed. This system should free the astronauts from localizing faults and reconfiguring loads if problems with the power distribution and generation components occur. The control system uses an object-oriented simulation model of the power system and first principle knowledge to detect, identify, and isolate faults. Each power system component is represented as a separate object with knowledge of its normal behavior. The reasoning process takes place at three different levels of abstraction: the Physical Component Model (PCM) level, the Electrical Equivalent Model (EEM) level, and the Functional System Model (FSM) level, with the PCM the lowest level of abstraction and the FSM the highest. At the EEM level the power system components are reasoned about as their electrical equivalents, e.g, a resistive load is thought of as a resistor. However, at the PCM level detailed knowledge about the component's specific characteristics is taken into account. The FSM level models the system at the subsystem level, a level appropriate for reconfiguration and scheduling. The control system operates in two modes, a reactive and a proactive mode, simultaneously. In the reactive mode the control system receives measurement data from the power system and compares these values with values determined through simulation to detect the existence of a fault. The nature of the fault is then identified through a model-based reasoning process using mainly the EEM. Compound component models are constructed at the EEM level and used in the fault identification process. In the proactive mode the reasoning takes place at the PCM level. Individual components determine their future health status using a physical model and measured historical data. In case changes in the health status seem imminent the component warns the control system about its impending failure. The fault isolation process uses the FSM level for its reasoning base.

Mathematical modeling of a thermovoltaic cell

NASA Technical Reports Server (NTRS)

White, Ralph E.; Kawanami, Makoto

1992-01-01

A new type of battery named 'Vaporvolt' cell is in the early stage of its development. A mathematical model of a CuO/Cu 'Vaporvolt' cell is presented that can be used to predict the potential and the transport behavior of the cell during discharge. A sensitivity analysis of the various transport and electrokinetic parameters indicates which parameters have the most influence on the predicted energy and power density of the 'Vaporvolt' cell. This information can be used to decide which parameters should be optimized or determined more accurately through further modeling or experimental studies. The optimal thicknesses of electrodes and separator, the concentration of the electrolyte, and the current density are determined by maximizing the power density. These parameter sensitivities and optimal design parameter values will help in the development of a better CuO/Cu 'Vaporvolt' cell.

A novel high-performance self-powered ultraviolet photodetector: Concept, analytical modeling and analysis

NASA Astrophysics Data System (ADS)

Ferhati, H.; Djeffal, F.

2017-12-01

In this paper, a new MSM-UV-photodetector (PD) based on dual wide band-gap material (DM) engineering aspect is proposed to achieve high-performance self-powered device. Comprehensive analytical models for the proposed sensor photocurrent and the device properties are developed incorporating the impact of DM aspect on the device photoelectrical behavior. The obtained results are validated with the numerical data using commercial TCAD software. Our investigation demonstrates that the adopted design amendment modulates the electric field in the device, which provides the possibility to drive appropriate photo-generated carriers without an external applied voltage. This phenomenon suggests achieving the dual role of effective carriers' separation and an efficient reduce of the dark current. Moreover, a new hybrid approach based on analytical modeling and Particle Swarm Optimization (PSO) is proposed to achieve improved photoelectric behavior at zero bias that can ensure favorable self-powered MSM-based UV-PD. It is found that the proposed design methodology has succeeded in identifying the optimized design that offers a self-powered device with high-responsivity (98 mA/W) and superior ION/IOFF ratio (480 dB). These results make the optimized MSM-UV-DM-PD suitable for providing low cost self-powered devices for high-performance optical communication and monitoring applications.

Power generation method including membrane separation

DOEpatents

Lokhandwala, Kaaeid A.

2000-01-01

A method for generating electric power, such as at, or close to, natural gas fields. The method includes conditioning natural gas containing C.sub.3+ hydrocarbons and/or acid gas by means of a membrane separation step. This step creates a leaner, sweeter, drier gas, which is then used as combustion fuel to run a turbine, which is in turn used for power generation.

Power Loss Analysis and Comparison of Segmented and Unsegmented Energy Coupling Coils for Wireless Energy Transfer

PubMed Central

Tang, Sai Chun; McDannold, Nathan J.

2015-01-01

This paper investigated the power losses of unsegmented and segmented energy coupling coils for wireless energy transfer. Four 30-cm energy coupling coils with different winding separations, conductor cross-sectional areas, and number of turns were developed. The four coils were tested in both unsegmented and segmented configurations. The winding conduction and intrawinding dielectric losses of the coils were evaluated individually based on a well-established lumped circuit model. We found that the intrawinding dielectric loss can be as much as seven times higher than the winding conduction loss at 6.78 MHz when the unsegmented coil is tightly wound. The dielectric loss of an unsegmented coil can be reduced by increasing the winding separation or reducing the number of turns, but the power transfer capability is reduced because of the reduced magnetomotive force. Coil segmentation using resonant capacitors has recently been proposed to significantly reduce the operating voltage of a coil to a safe level in wireless energy transfer for medical implants. Here, we found that it can naturally eliminate the dielectric loss. The coil segmentation method and the power loss analysis used in this paper could be applied to the transmitting, receiving, and resonant coils in two- and four-coil energy transfer systems. PMID:26640745

Power Loss Analysis and Comparison of Segmented and Unsegmented Energy Coupling Coils for Wireless Energy Transfer.

PubMed

Tang, Sai Chun; McDannold, Nathan J

2015-03-01

This paper investigated the power losses of unsegmented and segmented energy coupling coils for wireless energy transfer. Four 30-cm energy coupling coils with different winding separations, conductor cross-sectional areas, and number of turns were developed. The four coils were tested in both unsegmented and segmented configurations. The winding conduction and intrawinding dielectric losses of the coils were evaluated individually based on a well-established lumped circuit model. We found that the intrawinding dielectric loss can be as much as seven times higher than the winding conduction loss at 6.78 MHz when the unsegmented coil is tightly wound. The dielectric loss of an unsegmented coil can be reduced by increasing the winding separation or reducing the number of turns, but the power transfer capability is reduced because of the reduced magnetomotive force. Coil segmentation using resonant capacitors has recently been proposed to significantly reduce the operating voltage of a coil to a safe level in wireless energy transfer for medical implants. Here, we found that it can naturally eliminate the dielectric loss. The coil segmentation method and the power loss analysis used in this paper could be applied to the transmitting, receiving, and resonant coils in two- and four-coil energy transfer systems.

ACTN3 R577X polymorphism and explosive leg-muscle power in elite basketball players.

PubMed

Garatachea, Nuria; Verde, Zoraida; Santos-Lozano, Alejandro; Yvert, Thomas; Rodriguez-Romo, Gabriel; Sarasa, Francisco J; Hernández-Sánchez, Sonsoles; Santiago, Catalina; Lucia, Alejandro

2014-03-01

To determine the association of the ACTN3 R577X polymorphism with leg-muscle explosive power in Spanish (white) elite basketball players and controls. 100 (60 men) elite basketball players (cases) and 283 nonathletic controls. The authors assessed power performance by means of the vertical-squat and countermovement-jump tests. Genotype distributions did not differ between groups (cases: 37.0% [RR], 42.0% [RX], and 21.0% [XX]; controls: 31.8% [RR], 49.8% [RX], and 18.4% [XX]; P = .353). The authors did not observe any effect of the ACTN3 R577X polymorphism on study phenotypes in either group, including when they performed the analyses separately in men and women. They found no association between the ACTN3 R577X polymorphism and the likelihood of being an elite basketball player using the dominant or the recessive model, and the results remained unaltered when the analyses were adjusted for sex, weight, height, and age or when performed for men and women separately. Although the ACTN3 R577X is associated with explosive muscle performance and this phenotype is important in the sport of basketball (ie, during jumps), the authors found no association with leg explosive power in elite basket players or with the status of being this type of athlete.

Coordinated Scheduling for Interdependent Electric Power and Natural Gas Infrastructures

DOE PAGES

Zlotnik, Anatoly; Roald, Line; Backhaus, Scott; ...

2016-03-24

The extensive installation of gas-fired power plants in many parts of the world has led electric systems to depend heavily on reliable gas supplies. The use of gas-fired generators for peak load and reserve provision causes high intraday variability in withdrawals from high-pressure gas transmission systems. Such variability can lead to gas price fluctuations and supply disruptions that affect electric generator dispatch, electricity prices, and threaten the security of power systems and gas pipelines. These infrastructures function on vastly different spatio-temporal scales, which prevents current practices for separate operations and market clearing from being coordinated. Here in this article, wemore » apply new techniques for control of dynamic gas flows on pipeline networks to examine day-ahead scheduling of electric generator dispatch and gas compressor operation for different levels of integration, spanning from separate forecasting, and simulation to combined optimal control. We formulate multiple coordination scenarios and develop tractable physically accurate computational implementations. These scenarios are compared using an integrated model of test networks for power and gas systems with 24 nodes and 24 pipes, respectively, which are coupled through gas-fired generators. The analysis quantifies the economic efficiency and security benefits of gas-electric coordination and dynamic gas system operation.« less

Indirect current control with separate IZ drop compensation for voltage source converters

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

Kanetkar, V.R.; Dawande, M.S.; Dubey, G.K.

1995-12-31

Indirect Current Control (ICC) of boost type Voltage Source Converters (VSCs) using separate compensation of line IZ voltage drop is presented. A separate bi-directional VSC is used to produce the compensation voltage. This simplifies the ICC regulator scheme as the power flow is controlled through single modulation index. Experimental verification is provided for bi-directional control of the power flow.

Coaxial Compound Helicopter for Confined Urban Operations

DTIC Science & Technology

2016-01-22

climb or descent power for the aircraft) is obtained from the wind axis drag force and rotor velocity: ! Pp = "XV . The induced power is...speed. The induced and profile power cannot be measured separately in a wind tunnel or flight test, only the sum is available from ! P i + P o = P...XV (if the rotor wind -axis drag force ! X is measured or estimated). Therefore analysis is used to separate induced and profile power. In this

Improved system integration for integrated gasification combined cycle (IGCC) systems.

PubMed

Frey, H Christopher; Zhu, Yunhua

2006-03-01

Integrated gasification combined cycle (IGCC) systems are a promising technology for power generation. They include an air separation unit (ASU), a gasification system, and a gas turbine combined cycle power block, and feature competitive efficiency and lower emissions compared to conventional power generation technology. IGCC systems are not yet in widespread commercial use and opportunities remain to improve system feasibility via improved process integration. A process simulation model was developed for IGCC systems with alternative types of ASU and gas turbine integration. The model is applied to evaluate integration schemes involving nitrogen injection, air extraction, and combinations of both, as well as different ASU pressure levels. The optimal nitrogen injection only case in combination with an elevated pressure ASU had the highest efficiency and power output and approximately the lowest emissions per unit output of all cases considered, and thus is a recommended design option. The optimal combination of air extraction coupled with nitrogen injection had slightly worse efficiency, power output, and emissions than the optimal nitrogen injection only case. Air extraction alone typically produced lower efficiency, lower power output, and higher emissions than all other cases. The recommended nitrogen injection only case is estimated to provide annualized cost savings compared to a nonintegrated design. Process simulation modeling is shown to be a useful tool for evaluation and screening of technology options.

Poynting Vector in High-Temperature Superconducting Transformers with a Separate Excitation Winding

NASA Astrophysics Data System (ADS)

Volkov, E. P.; Dzhafarov, E. A.

2017-12-01

The HTSC transformer with a separate winding for excitation of the mutual magnetic flux is considered; the windings of the transformer are performed of first- or second-generation HTSC wires. The article presents the design and the electrical circuit of the transformer, the equations of electromagnetic balance, and the total resistance of the primary and secondary power windings and the separate excitation winding. The transfer of the electromagnetic field energy is considered in a single-phase HTSC transformer with the separate excitation winding using the Poynting vector. The temporal change in the reactive and active components of the Poynting vector and the decrease in the leakage energy flux of the separate excitation winding are shown, which causes an increase in the critical current density of the HTSC power windings, a decrease in the energy losses in the latter, and an increase the in the specific power of the HTSC transformer.

Integrating water use into Southern California's power dispatch: an evaluation of the potential for cost-effective water conservation

NASA Astrophysics Data System (ADS)

Bolorinos, J.; Ajami, N.; Yu, Y.; Rajagopal, R.

2016-12-01

Urban water supply and energy systems in the arid Southwestern United States are closely linked. Freshwater use by the electricity sector in particular represents a sizable portion of total water consumption in the region. Nonetheless, the dispatch of water and energy resources is managed separately, and no research to-date has examined the water conservation potential presented by the electricity sector. This study gauges the potential water savings that could be achieved including water use in the power dispatch process in Southern California by simulating a DC Optimal Power Flow for a simplified model of the region's power network. The simulation uses historical power consumption data, historical power production data and water use data from the US Geological Survey, the California Energy Commission and the US Energy Information Administration to estimate freshwater consumption by the region's thermoelectric power generation fleet. Preliminary results indicate that power system freshwater consumption could be reduced by as much as 20% at a minimal cost penalty, with potential for even greater savings. Model results show that Southern California's power system has the ability to competitively shift the use of some of the region's water resources from electricity to urban consumption, and suggests that water use should be incorporated into the policy-making process to enhance the efficient use of the state's interconnected water and energy resources.

Strategic Potential of the Late Ottoman Empire

DTIC Science & Technology

2001-01-01

pluristic society and separation of powers . Additionally, the U.S. should provide training and assistance to the military and police regarding the...convince Turkey’s leaders that strength in diversity and through separation of powers will promote greater internal security and prosperity

Political and legal institutions and their influence on drug policy: an Australian perspective.

PubMed

Ryder, David

2008-07-01

Under a federal system of government, political power is separated and distributed between different institutions of government. The distribution of power to enact policies that influence alcohol and other drug use can impact on the associated harm. A description of the separation of powers under a federal system of government is followed by three case studies of alcohol and other drug policies which have been influenced by the use of power by different institutions of government. Whether or not a policy is enacted depends upon who has the power to bring such a policy into being, who has the power to prevent its enactment and whether those with such power choose to use them. The enactment of policy is a political act, needing to be understood by those wishing to see evidence-based policies brought into being. An understanding of the separation of powers under a federal system of government is one aspect of the political process that those who work in the alcohol and other drug field need to understand.

Three essays on "making" electric power markets

NASA Astrophysics Data System (ADS)

Kench, Brian Thomas

2000-10-01

Technological change over the past three decades has altered most of the basic conditions in the electric power industry. Because of technical progress, the dominant paradigm has shifted from the provision of electric power by regulated and vertically integrated local natural monopolies to competition and vertical separation. In the first essay I provide a historical context of the electric industry's power current deregulation debate. Then a dynamic model of induced institutional change is used to investigate how endogenous technological advancements have induced radical institutional change in the generation and transmission segments of the electric power industry. Because the Federal Energy Regulatory Commission (FERC) ordered regulated utilities to provide open access to their transmission networks and to separate their generation and transmission functions, transmission networks have been used more intensively and in much different ways then in the past. The second essay tests experimentally the predictions of neoclassical theory for a radial electric power market under two alternative deregulated transmission institutions: financial transmission rights and physical transmission rights. Experimental evidence presented there demonstrates that an electric power market with physical transmission rights governing its transmission network generates more "right" market signals relative to a transmission network governed by financial transmission rights. The move to a greater reliance on markets for electric power is an idea that has animated sweeping and dramatic changes in the traditional business of electric power. The third essay examines two of the most innovative and complex initiatives of making electric power markets in the United States: California and PJM. As those markets mature and others are made, they must revise their governance mechanisms to eliminate rules that create inefficiency and adopt rules that work efficiently elsewhere. I argue that restructured electric power markets in the United States we should consider adopting an integrated procurement approach for electric power and ancillary services, binding forward markets for those commodities, and a market for physical transmission rights.

Spectroscopic investigation of species separation in opening switch plasmas

NASA Astrophysics Data System (ADS)

Jackson, S. L.; Phipps, D. G.; Richardson, A. S.; Commisso, R. J.; Hinshelwood, D. D.; Murphy, D. P.; Schumer, J. W.; Weber, B. V.; Boyer, C. N.; Doron, R.; Biswas, S.; Maron, Y.

2015-11-01

Interactions between magnetic fields and current-carrying plasmas that lead to the separation of plasma species in multi-species plasmas are being studied in a plasma opening switch geometry. Several Marshall guns are used to inject single or multi-species plasmas between coaxial conductors connected to the output of the Naval Research Laboratory's Hawk pulsed-power generator. Following injection of the plasma, the generator is used at roughly half power to apply an electrical pulse with a peak current of 450 kA, a peak voltage of 400 kV, and a rise time of 1.2 μs. The resulting magnetic field interacts with the plasma through a combination of field penetration and magnetohydrodynamic (MHD) pushing that is not well understood but can lead to the separation of plasma species in multi-species plasmas. An ICCD-coupled spectrometer has been used in combination with magnetic probes, a ribbon-beam interferometer, and particle-in-cell (PIC) modeling to diagnose and understand conditions in the plasma from the time it is injected until the end of the conduction phase of the opening switch. This work supported by the Naval Research Laboratory Base Program and the Office of Naval Research.

A perturbative approach to the redshift space correlation function: beyond the Standard Model

NASA Astrophysics Data System (ADS)

Bose, Benjamin; Koyama, Kazuya

2017-08-01

We extend our previous redshift space power spectrum code to the redshift space correlation function. Here we focus on the Gaussian Streaming Model (GSM). Again, the code accommodates a wide range of modified gravity and dark energy models. For the non-linear real space correlation function used in the GSM we use the Fourier transform of the RegPT 1-loop matter power spectrum. We compare predictions of the GSM for a Vainshtein screened and Chameleon screened model as well as GR. These predictions are compared to the Fourier transform of the Taruya, Nishimichi and Saito (TNS) redshift space power spectrum model which is fit to N-body data. We find very good agreement between the Fourier transform of the TNS model and the GSM predictions, with <= 6% deviations in the first two correlation function multipoles for all models for redshift space separations in 50Mpch <= s <= 180Mpc/h. Excellent agreement is found in the differences between the modified gravity and GR multipole predictions for both approaches to the redshift space correlation function, highlighting their matched ability in picking up deviations from GR. We elucidate the timeliness of such non-standard templates at the dawn of stage-IV surveys and discuss necessary preparations and extensions needed for upcoming high quality data.

Instructor Apathy and the Malaise of Listless Colleges. Part 1: A Pathologist's Report on the Fact-Value Distinction.

ERIC Educational Resources Information Center

Williams, Richard L.

The reported "malaise" of college instructors of the social sciences, particularly in political science, has its roots in the attempt to model the social sciences after the natural sciences and thus to separate fact from value. Scientific method requires that politics be redefined as an activity involving relationships of power, rule, and…

Simulation Methods for Design of Networked Power Electronics and Information Systems

DTIC Science & Technology

2014-07-01

Insertion of latency in every branch and at every node permits the system model to be efficiently distributed across many separate computing cores. An... the system . We demonstrated extensibility and generality of the Virtual Test Bed (VTB) framework to support multiple solvers and their associated...Information Systems Objectives The overarching objective of this program is to develop methods for fast

78 FR 32576 - Proposed Airworthiness Design Standards; AQUILA Aviation by Excellence GmbH, Model AT01

Federal Register 2010, 2011, 2012, 2013, 2014

2013-05-31

... aeroplanes, each power or thrust control must be designed so that if the control separates at the engine fuel... control toward lean or shut-off position. (b) Each manual engine mixture control must be designed so that... any generator; and (5) Each generator must have an overvoltage control designed and installed to...

Analysis of multilayer and single layer X-ray detectors for contrast-enhanced mammography using imaging task

NASA Astrophysics Data System (ADS)

Allec, Nicholas; Abbaszadeh, Shiva; Karim, Karim S.

2011-03-01

A multilayer (single-shot) detector has previously been proposed for contrast-enhanced mammography. The multilayer detector has the benefit of avoiding motion artifacts due to simultaneous acquisition of both high and low energy images. A single layer (dual-shot) detector has the benefit of better control over the energy separation since the incident beams can be produced and filtered separately. In this paper the performance of the multilayer detector is compared to that of a single layer detector using an ideal observer detectability index which is determined from an extended cascaded systems model and a defined imaging task. The detectors are assumed to have amorphous selenium direct conversion layers, however the same theoretical techniques used here may be applied to other types of integrating detectors. The anatomical noise caused by variation of glandularity within the breast is known to dominate the noise power spectrum at low frequencies due to its inverse power law dependence and is thus taken into account in our model to provide an accurate estimate of the detectability index. The conditions leading to the optimal detectability index, such as tube voltage, filtration, and weight factor are reported for both detector designs.

Aerodynamic Testing of the Orion Launch Abort Tower Separation with Jettison Motor Jet Interactions

NASA Technical Reports Server (NTRS)

Rhode, Matthew N.; Chan, David T.; Niskey, Charles J.; Wilson, Thomas M.

2011-01-01

The aerodynamic database for the Orion Launch Abort System (LAS) was developed largely from wind tunnel tests involving powered jet simulations of the rocket exhaust plumes, supported by computational fluid dynamics (CFD) simulations. The LAS contains three solid rocket motors used in various phases of an abort to provide propulsion, steering, and Launch Abort Tower (LAT) jettison from the Crew Module (CM). This paper describes a pair of wind tunnel experiments performed at transonic and supersonic speeds to determine the aerodynamic effects due to proximity and jet interactions during LAT jettison from the CM at the end of an abort. The tests were run using two different scale models at angles of attack from 150deg to 200deg , sideslip angles from -10deg to +10deg , and a range of powered thrust levels from the jettison motors to match various jet simulation parameters with flight values. Separation movements between the CM and LAT included axial and vertical translations as well as relative pitch angle between the two bodies. The paper details aspects of the model design, nozzle scaling methodology, instrumentation, testing procedures, and data reduction. Sample data are shown to highlight trends seen in the results.

Constitutional Issues: Separation of Powers.

ERIC Educational Resources Information Center

Gray, Leslie; Burroughs, Wynell

1987-01-01

Using a copy of a February 1937 letter from the publisher of the Gannett newspapers as a discussion springboard, this article provides historical background and teaching suggestions for addressing the issue of the separation of powers through Franklin Roosevelt's attempt to 'pack' the Supreme Court. (JDH)

The Train Wreck - An Invitation to Struggle

DTIC Science & Technology

1996-01-01

According to Alexander Hamilton in Federalist Number 73 the separation of powers intended to provide energy, dispatch, and independent deliberation The...and balances and separation of powers that can produce inaction when that IS appropriate Today’s paralysis IS the inaction of a government

Detention of U.S. Citizens

DTIC Science & Technology

2005-04-28

Detention of U.S. Citizens Louis Fisher Senior Specialist in Separation of Powers Government and Finance Division Summary In 1971, Congress passed...Hence the amendment also has the consequence of doing patent violence to the constitutional principle of separation of powers .” Id. at 31542

Common source-multiple load vs. separate source-individual load photovoltaic system

NASA Technical Reports Server (NTRS)

Appelbaum, Joseph

1989-01-01

A comparison of system performance is made for two possible system setups: (1) individual loads powered by separate solar cell sources; and (2) multiple loads powered by a common solar cell source. A proof for resistive loads is given that shows the advantage of a common source over a separate source photovoltaic system for a large range of loads. For identical loads, both systems perform the same.

Separation of Carbon Monoxide and Carbon Dioxide for Mars ISRU-Concepts

NASA Technical Reports Server (NTRS)

LeVan, M. Douglas; Finn, John E.; Sridhar, K. R.

2000-01-01

Solid oxide electrolyzers, such as electrolysis cells utilizing yttria-stabilized zirconia, can produce oxygen from Mars atmospheric carbon dioxide and reject carbon monoxide and unreacted carbon dioxide in a separate stream. The oxygen-production process has been shown to be far more efficient if the high-pressure, unreacted carbon dioxide can be separated and recycled back into the feed stream. Additionally, the mass of the adsorption compressor can be reduced. Also, the carbon monoxide by-product is a valuable fuel for space exploration and habitation, with applications from fuel cells to production of hydrocarbons and plastics. In our research, we will design, construct, and test an innovative, robust, low mass, low power separation device that can recover carbon dioxide and carbon monoxide for Mars ISRU. Such fundamental process technology, involving gas-solid phase separation in a reduced gravitational environment, will help to enable Human Exploration and Development of Space. The separation device will be scaled to operate with a CO2 sorption compressor and a zirconia electrolysis device built at the NASA Ames Research Center and the University of Arizona, respectively. In our research, we will design, construct, and test an innovative, robust, low mass, low power separation device that can recover carbon dioxide and carbon monoxide for Mars ISRU, Such fundamental process technology, involving gas-solid phase separation in a reduced gravitational environment, will help to enable Human Exploration and Development of Space. The separation device will be scaled to operate with a CO2 sorption compressor and a zirconia electrolysis device built at the NASA Ames Research Center and the University of Arizona, The separation device will be scaled to operate with a CO2 sorption compressor and a zirconia electrolysis device built at the NASA Ames Research Center and the University of Arizona, Research needs for the design shown are as follows: (1) The best adsorbent for the process must be determined. (2) Adsorption isotherms must be measured, both for pure components and mixtures. (3) Mathematical modeling must be performed to provide a solid framework for design. (4) The separation system must be constructed and tested. (5) System integration must be studied.

Morphology dependent near-field response in atomistic plasmonic nanocavities.

PubMed

Chen, Xing; Jensen, Lasse

2018-06-21

In this work we examine how the atomistic morphologies of plasmonic dimers control the near-field response by using an atomistic electrodynamics model. At large separations, the field enhancement in the junction follows a simple inverse power law as a function of the gap separation, which agrees with classical antenna theory. However, when the separations are smaller than 0.8 nm, the so-called quantum size regime, the field enhancement is screened and thus deviates from the simple power law. Our results show that the threshold distance for the deviation depends on the specific morphology of the junction. The near field in the junction can be localized to an area of less than 1 nm2 in the presence of an atomically sharp tip, but the separation distances leading to a large confinement of near field depend strongly on the specific atomistic configuration. More importantly, the highly confined fields lead to large field gradients particularly in a tip-to-surface junction, which indicates that such a plasmonic structure favors observing strong field gradient effects in near-field spectroscopy. We find that for atomically sharp tips the field gradient becomes significant and depends strongly on the local morphology of a tip. We expect our findings to be crucial for understanding the origin of high-resolution near-field spectroscopy and for manipulating optical cavities through atomic structures in the strongly coupled plasmonic systems.

Life Prediction Model for Grid-Connected Li-ion Battery Energy Storage System

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

Smith, Kandler A; Saxon, Aron R; Keyser, Matthew A

Lithium-ion (Li-ion) batteries are being deployed on the electrical grid for a variety of purposes, such as to smooth fluctuations in solar renewable power generation. The lifetime of these batteries will vary depending on their thermal environment and how they are charged and discharged. To optimal utilization of a battery over its lifetime requires characterization of its performance degradation under different storage and cycling conditions. Aging tests were conducted on commercial graphite/nickel-manganese-cobalt (NMC) Li-ion cells. A general lifetime prognostic model framework is applied to model changes in capacity and resistance as the battery degrades. Across 9 aging test conditions frommore » 0oC to 55oC, the model predicts capacity fade with 1.4% RMS error and resistance growth with 15% RMS error. The model, recast in state variable form with 8 states representing separate fade mechanisms, is used to extrapolate lifetime for example applications of the energy storage system integrated with renewable photovoltaic (PV) power generation.« less

Does the Separation of Powers Still Work?

ERIC Educational Resources Information Center

Wilson, James Q.

1987-01-01

The constitutional mandate of separation of powers preserves liberty and slows the pace of political change. Defects in this system are discussed. Remedies for the defects must be found in the "unwritten constitution," comprised of customs and arrangements that allow the government to work. (PS)

Two optimal working regimes of the ”long” Iguasu gas centrifuge

NASA Astrophysics Data System (ADS)

Borman, V. D.; Bogovalov, S. V.; Borisevich, V. D.; Tronin, I. V.; Tronin, V. N.

2016-09-01

We argue on the basis of the results of optimization calculations that the dependence of the optimal separative power of the Iguasu gas centrifuge with 2 m rotor has two local maxima,corresponding pressures of p max1 = 35 mmHg and p max2 = 350 mmHg. The optimal separative power values in these maxima differ by the value of 0.6%. Low pressure maximum is caused by the thermal drive, whereas high pressure maximum is caused by both thermal and mechanical drives. High pressure maximum is located on wide ’’plateau” from p 1 = 200 mmHg to p 2 = 500 mmHg, where the optimal separative power changes in the range of 0.7%. In this way, Iguasu gas centrifuge has two optimal working regimes with different sets of working parameters and close slightly different values of the separative power. Calculations show that high pressure regime is less sensitive to the parameters change than low pressure one.

Inductive sensor performance in partial discharges and noise separation by means of spectral power ratios.

PubMed

Ardila-Rey, Jorge Alfredo; Rojas-Moreno, Mónica Victoria; Martínez-Tarifa, Juan Manuel; Robles, Guillermo

2014-02-19

Partial discharge (PD) detection is a standardized technique to qualify electrical insulation in machines and power cables. Several techniques that analyze the waveform of the pulses have been proposed to discriminate noise from PD activity. Among them, spectral power ratio representation shows great flexibility in the separation of the sources of PD. Mapping spectral power ratios in two-dimensional plots leads to clusters of points which group pulses with similar characteristics. The position in the map depends on the nature of the partial discharge, the setup and the frequency response of the sensors. If these clusters are clearly separated, the subsequent task of identifying the source of the discharge is straightforward so the distance between clusters can be a figure of merit to suggest the best option for PD recognition. In this paper, two inductive sensors with different frequency responses to pulsed signals, a high frequency current transformer and an inductive loop sensor, are analyzed to test their performance in detecting and separating the sources of partial discharges.

Computational Investigations of Inboard Flow Separation and Mitigation Techniques on Multi-Megawatt Wind Turbines

NASA Astrophysics Data System (ADS)

Chow, Raymond

The aerodynamic characteristics of the NREL 5-MW rotor have been examined using a Reynolds-averaged Navier-Stokes method, OVERFLOW2. A comprehensive off-body grid independence study has been performed. A strong dependence on the size of the near-body wake grid has been found. Rapid diffusion of the wake appears to generate an overprediction of power and thrust. A large, continuous near-wake grid at minimum of two rotor diameters downstream of the rotor appears to be necessary for accurate predictions of near-body forces. The NREL 5-MW rotor demonstrates significant inboard flow separation up to 30% of span. This separation appears to be highly three-dimensional, with a significant amount of radial flow increasing the size of the separated region outboard. Both integrated aerodynamic coefficients and detailed wake structures for the baseline NREL 5-MW rotor are in excellent agreement with results by Riso at Uinfinity = 8 and 11 m/s. A simple, continuous full-chord fence was applied at the maximum chord location of the blade, within the region of separation. This non-optimized device reduced the boundary-layer cross-flow and resulting separation, and increased rotor power capture by 0.9% and 0.6% at U infinity = 8 and 11 m/s, respectively. Suction side only fences perform similarly in terms of power capture but reduce the increase in rotor thrust. Fence heights from 0.5% to 17.5% of the maximum chord all demonstrate some level of effectiveness, with fences (1-2.5%cmax) showing similar performance gains to taller fences with smaller penalties in thrust. Performance in terms of power capture is not very sensitive to spanwise location when placed within the separation region. Blunt trailing edge modifications to the inboard region of the blade showed a relatively significant effect on rotor power. Over a large range of trailing edge thicknesses from hTE = 10 to 25%c, power was found to increase by 1.4%. Thrust increased proportionally with the thicknesses examined, reaching a comparable increase of 1.4% by a trailing edge thickness of 15%c. Decreasing inboard twist only acted to increase thrust without increasing power capture any further at U infinity = 11 m/s. While increasing inboard blade twist decreased power, but decreased thrust at even a higher rate. Vortex generators were not successively configured to significantly improve power capture in this study. Two of the three configurations examined actually decreased power capture and increased the separation region. The results found in this study are not believed to be representative of a properly sized and located array of VGs. The presence of the nose cone and nacelle body at the hub of the rotor is found to have a minimal effect on the power and thrust of the overall rotor. The downstream wake structure however is changed by the nacelle, potentially useful for wake tailoring when turbines are closely spaced together.

Vector Autoregression, Structural Equation Modeling, and Their Synthesis in Neuroimaging Data Analysis

PubMed Central

Chen, Gang; Glen, Daniel R.; Saad, Ziad S.; Hamilton, J. Paul; Thomason, Moriah E.; Gotlib, Ian H.; Cox, Robert W.

2011-01-01

Vector autoregression (VAR) and structural equation modeling (SEM) are two popular brain-network modeling tools. VAR, which is a data-driven approach, assumes that connected regions exert time-lagged influences on one another. In contrast, the hypothesis-driven SEM is used to validate an existing connectivity model where connected regions have contemporaneous interactions among them. We present the two models in detail and discuss their applicability to FMRI data, and interpretational limits. We also propose a unified approach that models both lagged and contemporaneous effects. The unifying model, structural vector autoregression (SVAR), may improve statistical and explanatory power, and avoids some prevalent pitfalls that can occur when VAR and SEM are utilized separately. PMID:21975109

Effect of laser cavity parameters on saturation of light – current characteristics of high-power pulsed lasers

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

Veselov, D A; Pikhtin, N A; Lyutetskiy, A V

2015-07-31

We report an experimental study of power characteristics of semiconductor lasers based on MOVPE-grown asymmetric separate-confinement heterostructures with a broadened waveguide as functions of cavity length, stripe contact width and mirror reflectivities. It is shown that at high current pump levels, the variation of the cavity parameters of a semiconductor laser (width, length and mirror reflectivities) influences the light – current (L – I) characteristic saturation and maximum optical power by affecting such laser characteristics, as the current density and the optical output loss. A model is elaborated and an optical power of semiconductor lasers is calculated by taking intomore » account the dependence of the internal optical loss on pump current density and concentration distribution of charge carriers and photons along the cavity axis of the cavity. It is found that only introduction of the dependence of the internal optical loss on pump current density to the calculation model provides a good agreement between experimental and calculated L – I characteristics for all scenarios of variations in the laser cavity parameters. (lasers)« less

To Control the Abuses of Government: The Veto and the Separation of Powers. A Guide for Discussion of Proposals to Institute Item and Legislative Veto Powers.

ERIC Educational Resources Information Center

O'Connor, Alice; Henze, Mary L.

A discussion guide, one of a series on constitutional reform issues by The Jefferson Foundation as part of The Jefferson Meeting on the Constitution project, examines proposals to institute item and legislative veto power. The first section discusses the historical background surrounding the formative debate on veto legislation. The separation of…

KLYNAC: Compact linear accelerator with integrated power supply

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

Malyzhenkov, Alexander

Accelerators and accelerator-based light sources have a wide range of applications in science, engineering technology and medicine. Today the scienti c community is working towards improving the quality of the accelerated beam and its parameters while trying to develop technology for reducing accelerator size. This work describes a design of a compact linear accelerator (linac) prototype, resonant Klynac device, which is a combined linear accelerator and its power supply - klystron. The intended purpose of a Klynac device is to provide a compact and inexpensive alternative to a conventional 1 to 6 MeV accelerator, which typically requires a separate RFmore » source, an accelerator itself and all the associated hardware. Because the Klynac is a single structure, it has the potential to be much less sensitive to temperature variations than a system with separate klystron and linac. We start by introducing a simpli ed theoretical model for a Klynac device. We then demonstrate how a prototype is designed step-by-step using particle-in-cell simulation studies for mono- resonant and bi-resonant structures. Finally, we discuss design options from a stability point of view and required input power as well as behavior of competing modes for the actual built device.« less

Experimental Results for Temporally Overlapping Pulses from Quantel EverGreen 200 Laser

NASA Technical Reports Server (NTRS)

Watkins, A. Neal

2013-01-01

This report will detail the experimental results and observations obtained while investigating the feasibility of temporally overlapping the two laser pulses from a Quantel EverGreen 200 Laser. This laser was specifically designed for Particle Imaging Velocimetry (PIV) applications and operate by emitting two 532 nm laser pulses that are seperated by an adjustable finite time (typically on the order of ten to hundreds of microseconds). However, the use of this model laser has found recent application for Pressure Sensitive Paint (PSP) testing, especially for rotorcraft research. For this testing, it is desired to only use one laser pulse. While this is easily done by only firing one of the laser heads, more excitation energy could conceivably be had if both laser heads are fired with zero pulse separation. In addition, recently large field-of-view PIV measurements have become possible and need ever increasing laser power to illuminate the larger areas. For this work, two different methods of timing the laser are investigated using both a traditional power meter to monitor laser power as well as a fast photodiode to determine pulse separation. The results are presented here as well as some simple implications for PIV experiments using these methods.

Klynac: Compact Linear Accelerator with Integrated Power Supply

NASA Astrophysics Data System (ADS)

Malyzhenkov, A. V.

Accelerators and accelerator-based light sources have a wide range of applications in science, engineering technology and medicine. Today the scientific community is working towards improving the quality of the accelerated beam and its parameters, while trying to develop technology for reducing accelerator size. This work describes a design of a compact linear accelerator (linac) prototype: resonant Klynac device, which is a combined linear accelerator and its power supply - klystron. The intended purpose of a Klynac device is to provide a compact and inexpensive alternative to a conventional 1 to 6 MeV accelerator, which typically requires a separate RF source, accelerator itself and all the associated hardware. Because the Klynac is a single structure, it has the potential to be much less sensitive to temperature variations than a system with separate klystron and linac. We start by introducing a simplified theoretical model for a Klynac device. We then demonstrate how a prototype is designed step-by-step using Particle-In-Cell simulation studies for mono-resonant and bi-resonant structures. Finally, we discuss design options from a stability point of view and required input power as well as behavior of competing modes for the actual built device.

Microscale anechoic architecture: acoustic diffusers for ultra low power microparticle separation via traveling surface acoustic waves.

PubMed

Behrens, Jan; Langelier, Sean; Rezk, Amgad R; Lindner, Gerhard; Yeo, Leslie Y; Friend, James R

2015-01-07

We present a versatile and very low-power traveling SAW microfluidic sorting device able to displace and separate particles of different diameter in aqueous suspension; the travelling wave propagates through the fluid bulk and diffuses via a Schröder diffuser, adapted from its typical use in concert hall acoustics to be the smallest such diffuser to be suitable for microfluidics. The effective operating power range is two to three orders of magnitude less than current SAW devices, uniquely eliminating the need for amplifiers, and by using traveling waves to impart forces directly upon suspended microparticles, they can be separated by size.

An analytical design approach for self-powered active lateral secondary suspensions for railway vehicles

NASA Astrophysics Data System (ADS)

Wang, Peng; Li, Hong; Zhang, Jiye; Mei, TX

2015-10-01

In this paper, an analytical design approach for the development of self-powered active suspensions is investigated and is applied to optimise the control system design for an active lateral secondary suspension for railway vehicles. The conditions for energy balance are analysed and the relationship between the ride quality improvement and energy consumption is discussed in detail. The modal skyhook control is applied to analyse the energy consumption of this suspension by separating its dynamics into the lateral and yaw modes, and based on a simplified model, the average power consumption of actuators is computed in frequency domain by using the power spectral density of lateral alignment of track irregularities. Then the impact of control gains and actuators' key parameters on the performance for both vibration suppressing and energy recovery/storage is analysed. Computer simulation is used to verify the obtained energy balance condition and to demonstrate that the improved ride comfort is achieved by this self-powered active suspension without any external power supply.

Uncertainty Propagation in OMFIT

NASA Astrophysics Data System (ADS)

Smith, Sterling; Meneghini, Orso; Sung, Choongki

2017-10-01

A rigorous comparison of power balance fluxes and turbulent model fluxes requires the propagation of uncertainties in the kinetic profiles and their derivatives. Making extensive use of the python uncertainties package, the OMFIT framework has been used to propagate covariant uncertainties to provide an uncertainty in the power balance calculation from the ONETWO code, as well as through the turbulent fluxes calculated by the TGLF code. The covariant uncertainties arise from fitting 1D (constant on flux surface) density and temperature profiles and associated random errors with parameterized functions such as a modified tanh. The power balance and model fluxes can then be compared with quantification of the uncertainties. No effort is made at propagating systematic errors. A case study will be shown for the effects of resonant magnetic perturbations on the kinetic profiles and fluxes at the top of the pedestal. A separate attempt at modeling the random errors with Monte Carlo sampling will be compared to the method of propagating the fitting function parameter covariant uncertainties. Work supported by US DOE under DE-FC02-04ER54698, DE-FG2-95ER-54309, DE-SC 0012656.

Modeling and identifying the sources of radiocesium contamination in separate sewerage systems.

PubMed

Pratama, Mochamad Adhiraga; Yoneda, Minoru; Yamashiki, Yosuke; Shimada, Yoko; Matsui, Yasuto

2018-05-01

The Fukushima Dai-ichi nuclear power plant accident released radiocesium in large amounts. The released radionuclides contaminated much of the surrounding environment, including sewers in urban areas of Fukushima prefecture. In this study we attempted to identify and quantify the sources of radiocesium contamination in separate sewerage systems and developed a compartment model based on the Radionuclide Migration in Urban Environments and Drainage Systems (MUD) model. Measurements of the time-dependent radiocesium concentration in sewer sludge combined with meteorological, demographic, and radiocesium dietary intake data indicated that rainfall-derived inflow and infiltration (RDII) and human excretion were the chief contributors of radiocesium contamination in a separate sewerage system. The quantities of contamination derived from RDII and human excretion were calculated and used in the modified MUD model to simulate radiocesium contamination in sewers in three urban areas in Fukushima prefecture: Fukushima, Koriyama, and Nihonmatsu Cities. The Nash efficiency coefficient (0.88-0.92) and determination coefficient (0.89-0.93) calculated in an evaluation of our compartment model indicated that the model produced satisfactory results. We also used the model to estimate the total volume of sludge with radiocesium concentrations in excess of the clearance level, based on the number of months elapsed after the accident. Estimations by our model suggested that wastewater treatment plants (WWTPs) in Fukushima, Koriyama, and Nihonmatsu generated about 1,750,000m 3 of radioactive sludge in total, a level in good agreement with the real data. Copyright © 2017 Elsevier B.V. All rights reserved.

Defense Horizons. Privatizing While Transforming. July 2007, Number 57

DTIC Science & Technology

2007-07-01

accountability and separation of powers . Regarding the first, the more privatization is used, the greater the distance between both executive and...far end of that issue is a separation of powers question related to executive accountability to Congress. Just as the war on terror is generating

The Senate CTB Treaty Rejection: Prudent Statesmanship or Partisan Politics?

DTIC Science & Technology

1999-12-13

the Constitution the theory of separation of powers , which so many delegates had come to believe in.5...Fathers who had fought for the advice and consent clause and the principle of separation of powers in 1789 would have been pleased with the prudent

Strategic Forum Number 208: Turbulent Transition in Iraq: Can It Succeed?

DTIC Science & Technology

2004-06-01

ministers including a prime minister, and a judiciary. There is separation of powers —legislative, executive, and judicial. The assembly will elect the... separation of powers based on geographic and historical realities and not race, ethnicity, nationality, or religious sect (confession). Formulation of

Civilian Control of the Military Establishment

DTIC Science & Technology

1990-04-02

distinctive features of this Constitution was its incorporation of two doctrines that sees incompatible: separation of powers , and checks and balances.1...apparent tensions inherent in this Constitutional separation of powers . As a member of the U.S. Armed Forces, I began my service by taking an oath of

Control-structure interaction study for the Space Station solar dynamic power module

NASA Technical Reports Server (NTRS)

Cheng, J.; Ianculescu, G.; Ly, J.; Kim, M.

1991-01-01

The authors investigate the feasibility of using a conventional PID (proportional plus integral plus derivative) controller design to perform the pointing and tracking functions for the Space Station Freedom solar dynamic power module. Using this simple controller design, the control/structure interaction effects were also studied without assuming frequency bandwidth separation. From the results, the feasibility of a simple solar dynamic control solution with a reduced-order model, which satisfies the basic system pointing and stability requirements, is suggested. However, the conventional control design approach is shown to be very much influenced by the order of reduction of the plant model, i.e., the number of the retained elastic modes from the full-order model. This suggests that, for complex large space structures, such as the Space Station Freedom solar dynamic, the conventional control system design methods may not be adequate.

Enhanced oil recovery system

DOEpatents

Goldsberry, Fred L.

1989-01-01

All energy resources available from a geopressured geothermal reservoir are used for the production of pipeline quality gas using a high pressure separator/heat exchanger and a membrane separator, and recovering waste gas from both the membrane separator and a low pressure separator in tandem with the high pressure separator for use in enhanced oil recovery, or in powering a gas engine and turbine set. Liquid hydrocarbons are skimmed off the top of geothermal brine in the low pressure separator. High pressure brine from the geothermal well is used to drive a turbine/generator set before recovering waste gas in the first separator. Another turbine/generator set is provided in a supercritical binary power plant that uses propane as a working fluid in a closed cycle, and uses exhaust heat from the combustion engine and geothermal energy of the brine in the separator/heat exchanger to heat the propane.

Geothermal Power Potential in the Tatun Volcano Group, Taiwan

NASA Astrophysics Data System (ADS)

Tseng, H. H.; Song, S.

2013-12-01

Recent energy issues have concentrated the attention on finding alternative ones. National demands for renewable and sustainable energy increase rapidly, especially the geothermal power production, which is viewed as the most potential opportunity. This study attempts to estimate the geothermal powers in the Tatung Volcano Group (TVG), Taiwan and evaluate the possibility to develop the Enhanced Geothermal System. Tatung Volcano Group is located at the northwest part of Taiwan. It has violent volcanism during 0.8-0.20Ma, and is still active with many thermal manifestations. The young volcanic activity provides the TVG with high geothermal gradient and is well suitable for exploiting geothermal resources. Many explorations on geothermal energy have been accomplished in this area during1966-1973. They included resistivity survey, magnetic prospecting, gravity method, seismic prospecting and etc. In this study, we base on previous data and apply the probabilistic volumetric method proposed by Geotherm EX Inc., modified from the approach introduced by the USGS to evaluate the geothermal power potential in TVG. Meanwhile, use a Monte Carlo simulation technique to calculate the probability distribution of potentially recoverable energy reserves. The results show that the mean value is 270Mw, and P50 is 254Mw for 30 years, separately. Furthermore, the power potential of enhanced geothermal system in TVG is also estimated by the quantitative model proposed by Massachusetts Institute of Technology (MIT 2006). The results suggest that the mean value is 3,000 MW and P50 is 2,780 MW for 30 years, separately.

Selecting a Separable Parametric Spatiotemporal Covariance Structure for Longitudinal Imaging Data

PubMed Central

George, Brandon; Aban, Inmaculada

2014-01-01

Longitudinal imaging studies allow great insight into how the structure and function of a subject’s internal anatomy changes over time. Unfortunately, the analysis of longitudinal imaging data is complicated by inherent spatial and temporal correlation: the temporal from the repeated measures, and the spatial from the outcomes of interest being observed at multiple points in a patients body. We propose the use of a linear model with a separable parametric spatiotemporal error structure for the analysis of repeated imaging data. The model makes use of spatial (exponential, spherical, and Matérn) and temporal (compound symmetric, autoregressive-1, Toeplitz, and unstructured) parametric correlation functions. A simulation study, inspired by a longitudinal cardiac imaging study on mitral regurgitation patients, compared different information criteria for selecting a particular separable parametric spatiotemporal correlation structure as well as the effects on Type I and II error rates for inference on fixed effects when the specified model is incorrect. Information criteria were found to be highly accurate at choosing between separable parametric spatiotemporal correlation structures. Misspecification of the covariance structure was found to have the ability to inflate the Type I error or have an overly conservative test size, which corresponded to decreased power. An example with clinical data is given illustrating how the covariance structure procedure can be done in practice, as well as how covariance structure choice can change inferences about fixed effects. PMID:25293361

OVATION Prime -2013: Solar Wind Driven Precipitation Model Extended to Higher Geomagnetic Activity Levels (Invited)

NASA Astrophysics Data System (ADS)

Newell, P. T.; Liou, K.; Zhang, Y.; Paxton, L.; Sotirelis, T.; Mitchell, E. J.

2013-12-01

OVATION Prime is an auroral precipitation model parameterized by solar wind driving. Distinguishing features of the model include an optimized solar wind-magnetosphere coupling function (dΦMP/dt) which predicts auroral power far better than Kp or other traditional parameters, the separation of aurora into categories (diffuse aurora, monoenergetic, broadband, and ion), the inclusion of seasonal variations, and separate parameter fits for each MLATxMLT bin, thus permitting each type of aurora and each location to have differing responses to season and solar wind input (as indeed they do). We here introduce OVATION Prime-2013, an upgrade to the 2008 version currently widely available. The most notable advantage of OP-2013 is that it uses UV images from the GUVI instrument on the satellite TIMED for high disturbance levels (dΦMP/dt > 12,000 (nT2/3 (km/s)4/3 which roughly corresponds to Kp = 5+ or 6-). The range of validity is thought to be about 0 < dΦMP/dt = 30000 (say Kp = 8 or 8+). Other upgrades include a reduced susceptibility to salt and pepper noise, and smoother interpolation across the postmidnight data gap. We will also provide a comparison of the advantages and disadvantages of other current precipitation models, especially OVATION-SuperMAG, which produces particularly good estimates for total auroral power, at the expense of working best on an historical basis. OVATION Prime-2013, for high solar wind driving, as TIMED GUVI data takes over from DMSP

Fluidic Energy Harvester Optimization in Grid Turbulence

NASA Astrophysics Data System (ADS)

Danesh-Yazdi, Amir; Elvin, Niell; Andreopoulos, Yiannis

2017-11-01

Even though it is omnipresent in nature, there has not been a great deal of research in the literature involving turbulence as an energy source for piezoelectric fluidic harvesters. In the present work, a grid-generated turbulence forcing function model which we derived previously is employed in the single degree-of-freedom electromechanical equations to find the power output and tip displacement of piezoelectric cantilever beams. Additionally, we utilize simplified, deterministic models of the turbulence forcing function to obtain closed-form expressions for the power output. These theoretical models are studied using experiments that involve separately placing a hot-wire anemometer probe and a short PVDF beam in flows where turbulence is generated by means of passive and semi-passive grids. From a parametric study on the deterministic models, we show that the white noise forcing function best mimics the experimental data. Furthermore, our parametric study of the response spectrum of a generic fluidic harvester in grid-generated turbulent flow shows that optimum power output is attained for beams placed closer to the grid with a low natural frequency and damping ratio and a large electromechanical coupling coefficient. NSF Grant No. CBET 1033117.

Market power in electric power markets: Indications of competitiveness in spatial prices for wholesale electricity

NASA Astrophysics Data System (ADS)

Denton, Michael John

The issue of market delineation and power in the wholesale electric energy market is explored using three separate approaches: two of these are analyses of spatial pricing data to explore the functional size of the markets, and the third is a series of experimental tests of the effects of different cost structures and market mechanisms on oligopoly strength in those markets. An equilibrium model of spatial network competition is shown to yield linear relationships between spatial prices. A data set comprising two years of spatial weekly peak and off-peak prices and weather for 6 locations in the Western States Coordinating Council and the Southwest Power Pool is subjected to a pairwise cointegration analysis. The use of dummy variables to account the the flow directions is found to significantly improve model performance. The second analytical technique utilizes the extraction of principal components from a spatial price correlation matrix to identify the extent of natural markets. One year of daily price observations for eleven locations within the WSCC is compiled and eigenvectors are extracted and subjected to oblique rotation, each of which is then interpreted as representing a separate geographic market. The results show that two distinct natural markets, correlated at 84%, account for over 96% of the variation in the spatial prices in the WSSC. Together, the findings support the assertion that the wholesale electricity market in the Western U.S. is large and highly competitive. The experimental analysis utilizes a radial three node network in which suppliers located at the outer nodes sell to buyers located at the central node. The parameterization captures the salient characteristics of the existing bulk power markets, and includes cyclical demand, transmission losses, as well as fixed and avoidable fixed costs for all agents. Treatments varied the number of sellers, the avoidable fixed cost structures, and the trading mechanism. Results indicated that sealed bid markets greatly reduced the ability of sellers to exert market power. Overall the existence of higher avoidable fixed costs tended to ameliorate market power effects.

Impact of muon detection thresholds on the separability of primary cosmic rays

NASA Astrophysics Data System (ADS)

Müller, S.; Engel, R.; Pierog, T.; Roth, M.

2018-01-01

Knowledge of the mass composition of cosmic rays in the transition region of galactic to extragalactic cosmic rays is needed to discriminate different astrophysical models on their origin, acceleration, and propagation. An important observable to separate different mass groups of cosmic rays is the number of muons in extensive air showers. We performed a CORSIKA simulation study to analyze the impact of the detection threshold of muons on the separation quality of different primary cosmic rays in the energy region of the ankle. Using only the number of muons as the composition-sensitive observable, we find a clear dependence of the separation power on the detection threshold for ideal measurements. Although the number of detected muons increases when lowering the threshold, the discrimination power is reduced. If statistical fluctuations for muon detectors of limited size are taken into account, the threshold dependence remains qualitatively the same for small distances to the shower core but is reduced for large core distances. We interpret the impact of the detection threshold of muons on the composition sensitivity in terms of a change of the correlation of the number of muons nμ with the shower maximum Xmax as function of the muon energy as a result of the underlying hadronic interactions and the shower geometry. We further investigate the role of muons produced in a shower by photon-air interactions and conclude that, in addition to the effect of the nμ -Xmax correlation, the separability of primaries is reduced as a consequence of the presence of more muons from photonuclear reactions in proton than in iron showers.

Water and Power Systems Co-optimization under a High Performance Computing Framework

NASA Astrophysics Data System (ADS)

Xuan, Y.; Arumugam, S.; DeCarolis, J.; Mahinthakumar, K.

2016-12-01

Water and energy systems optimizations are traditionally being treated as two separate processes, despite their intrinsic interconnections (e.g., water is used for hydropower generation, and thermoelectric cooling requires a large amount of water withdrawal). Given the challenges of urbanization, technology uncertainty and resource constraints, and the imminent threat of climate change, a cyberinfrastructure is needed to facilitate and expedite research into the complex management of these two systems. To address these issues, we developed a High Performance Computing (HPC) framework for stochastic co-optimization of water and energy resources to inform water allocation and electricity demand. The project aims to improve conjunctive management of water and power systems under climate change by incorporating improved ensemble forecast models of streamflow and power demand. First, by downscaling and spatio-temporally disaggregating multimodel climate forecasts from General Circulation Models (GCMs), temperature and precipitation forecasts are obtained and input into multi-reservoir and power systems models. Extended from Optimus (Optimization Methods for Universal Simulators), the framework drives the multi-reservoir model and power system model, Temoa (Tools for Energy Model Optimization and Analysis), and uses Particle Swarm Optimization (PSO) algorithm to solve high dimensional stochastic problems. The utility of climate forecasts on the cost of water and power systems operations is assessed and quantified based on different forecast scenarios (i.e., no-forecast, multimodel forecast and perfect forecast). Analysis of risk management actions and renewable energy deployments will be investigated for the Catawba River basin, an area with adequate hydroclimate predicting skill and a critical basin with 11 reservoirs that supplies water and generates power for both North and South Carolina. Further research using this scalable decision supporting framework will provide understanding and elucidate the intricate and interdependent relationship between water and energy systems and enhance the security of these two critical public infrastructures.

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

Sule, Nishant; Yifat, Yuval; Gray, Stephen K.

We examine the formation and concomitant rotation of electrodynamically bound dimers (EBD) of 150nm diameter Ag nanoparticles trapped in circularly polarized focused Gaussian beams. The rotation frequency of an EBD increases linearly with the incident beam power, reaching high mean values of ~ 4kHz for a relatively low incident power of 14mW. Using a coupled-dipole/effective polarizability model, we reveal that retardation of the scattered fields and electrodynamic interactions can lead to a “negative torque” causing rotation of the EBD in the direction opposite to that of the circular polarization. This intriguing opposite-handed rotation due to negative torque is clearly demonstratedmore » using electrodynamics-Langevin dynamics simulations by changing particle separations and thus varying the retardation effects. Finally, negative torque is also demonstrated in experiments from statistical analysis of the EBD trajectories. These results demonstrate novel rotational dynamics of nanoparticles in optical matter using circular polarization and open a new avenue to control orientational dynamics through coupling to interparticle separation.« less

Cyber OODA: A Candidate Model for Cyberspace Engagement

DTIC Science & Technology

2010-06-01

of physical and syntactic limits, or viewing a content-rich PowerPoint presentation on a blackberry (viewable at low resolution, slow speeds, and...21 This is an ideal type definition. VPNs tunnel through traditional networks, but do not exchange information other than travel...instructions. As long as the VPN tunnel remains secure, it is treated as a separate cyberspace. If security breaks down logical cyberspaces will

Removal of Iron Oxide Scale from Feed-water in Thermal Power Plant by Using Magnetic Separation

NASA Astrophysics Data System (ADS)

Nakanishi, Motohiro; Shibatani, Saori; Mishima, Fumihito; Akiyama, Yoko; Nishijima, Shigehiro

2017-09-01

One of the factors of deterioration in thermal power generation efficiency is adhesion of the scale to inner wall in feed-water system. Though thermal power plants have employed All Volatile Treatment (AVT) or Oxygen Treatment (OT) to prevent scale formation, these treatments cannot prevent it completely. In order to remove iron oxide scale, we proposed magnetic separation system using solenoidal superconducting magnet. Magnetic separation efficiency is influenced by component and morphology of scale which changes their property depending on the type of water treatment and temperature. In this study, we estimated component and morphology of iron oxide scale at each equipment in the feed-water system by analyzing simulated scale generated in the pressure vessel at 320 K to 550 K. Based on the results, we considered installation sites of the magnetic separation system.

Cluster Analysis of Downscaled and Explicitly Simulated North Atlantic Tropical Cyclone Tracks

DOE PAGES

Daloz, Anne S.; Camargo, S. J.; Kossin, J. P.; ...

2015-02-11

A realistic representation of the North Atlantic tropical cyclone tracks is crucial as it allows, for example, explaining potential changes in U.S. landfalling systems. Here, the authors present a tentative study that examines the ability of recent climate models to represent North Atlantic tropical cyclone tracks. Tracks from two types of climate models are evaluated: explicit tracks are obtained from tropical cyclones simulated in regional or global climate models with moderate to high horizontal resolution (1°–0.25°), and downscaled tracks are obtained using a downscaling technique with large-scale environmental fields from a subset of these models. Here, for both configurations, tracksmore » are objectively separated into four groups using a cluster technique, leading to a zonal and a meridional separation of the tracks. The meridional separation largely captures the separation between deep tropical and subtropical, hybrid or baroclinic cyclones, while the zonal separation segregates Gulf of Mexico and Cape Verde storms. The properties of the tracks’ seasonality, intensity, and power dissipation index in each cluster are documented for both configurations. The authors’ results show that, except for the seasonality, the downscaled tracks better capture the observed characteristics of the clusters. The authors also use three different idealized scenarios to examine the possible future changes of tropical cyclone tracks under 1) warming sea surface temperature, 2) increasing carbon dioxide, and 3) a combination of the two. The response to each scenario is highly variable depending on the simulation considered. Lastly, the authors examine the role of each cluster in these future changes and find no preponderant contribution of any single cluster over the others.« less

Beyond the 2008 Justice Reforms: Establishing a Legitimate Rule of Law in Mexico with Jury Trials

DTIC Science & Technology

2011-10-28

States with separation of powers , including executive, legislative, and judicial branches, granted by the 1917 Constitution. The executive branch role...law system prevents an overreaching judicial branch from legislating new laws. This provides a strong separation of powers . However, when coupled

Turbulent Transition in Iraq: Can It Succeed? (Strategic Forum, Number 208, June 2004)

DTIC Science & Technology

2004-06-01

council, a council of ministers including a prime minister, and a judiciary. There is separation of powers —legislative, executive, and judicial. The...defined as a system of separation of powers based on geographic and historical realities and not race, ethnicity, nationality, or religious sect

Case Study: A Separation of Powers Lesson.

ERIC Educational Resources Information Center

Jenkins, Steve

1986-01-01

Presents a case study involving students in the issue of separation of powers as applied to the 1952 Immigration and Nationality Act. Students examine the case of Jagdish Rai Chadha, an immigrant threatened with deportation whose problems resulted in 1983 U.S. Supreme Court decision declaring legislative veto provision of Immigration and…

Origins of the 1986 Philippine Constitution

DTIC Science & Technology

1993-04-01

1902 and the Philippine Autonomy Act of 1916 (Jones Law) - did not expressly provide for the separation of powers . However, in various decisions, the...judiciary as part of the separation of powers was repeatedly declared by the Supreme Court of the Philippines to have been extended to the 11 Philippines

Separation of Powers: Checks and Balances.

ERIC Educational Resources Information Center

Taylor, Bonnie

1988-01-01

This article offers a class activity on separation of powers and checks and balances within the U.S. government. Based on Franklin Delano Roosevelt's attempt to push through legislation for the New Deal of the 1930s by "packing" the U.S. Supreme Court, the activity includes worksheets and teaching suggestions. (JDH)

Wind Power Curve Modeling in Simple and Complex Terrain

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

Bulaevskaya, V.; Wharton, S.; Irons, Z.

2015-02-09

Our previous work on wind power curve modeling using statistical models focused on a location with a moderately complex terrain in the Altamont Pass region in northern California (CA). The work described here is the follow-up to that work, but at a location with a simple terrain in northern Oklahoma (OK). The goal of the present analysis was to determine the gain in predictive ability afforded by adding information beyond the hub-height wind speed, such as wind speeds at other heights, as well as other atmospheric variables, to the power prediction model at this new location and compare the resultsmore » to those obtained at the CA site in the previous study. While we reach some of the same conclusions at both sites, many results reported for the CA site do not hold at the OK site. In particular, using the entire vertical profile of wind speeds improves the accuracy of wind power prediction relative to using the hub-height wind speed alone at both sites. However, in contrast to the CA site, the rotor equivalent wind speed (REWS) performs almost as well as the entire profile at the OK site. Another difference is that at the CA site, adding wind veer as a predictor significantly improved the power prediction accuracy. The same was true for that site when air density was added to the model separately instead of using the standard air density adjustment. At the OK site, these additional variables result in no significant benefit for the prediction accuracy.« less

Low Luminosity States of the Black Hole Candidate GX 339-4. 1; ASCA and Simultaneous Radio/RXTE Observations

NASA Technical Reports Server (NTRS)

Wilms, Joern; Nowak, Michael A.; Dove, James B.; Fender, Robert P.; DiMatteo, Tiziana

1998-01-01

We discuss a series of observations of the black hole candidate GX 339-4 in low luminosity, spectrally hard states. We present spectral analysis of three separate archival Advanced Satellite for Cosmology and Astrophysics (ASCA) data sets and eight separate Rossi X-ray Timing Explorer (RXTE) data sets. Three of the RXTE observations were strictly simultaneous with 843 Mega Hertz and 8.3-9.1 Giga Hertz radio observations. All of these observations have (3-9 keV) flux approximately less than 10(exp-9) ergs s(exp-1) CM(exp -2). The ASCA data show evidence for an approximately 6.4 keV Fe line with equivalent width approximately 40 eV, as well as evidence for a soft excess that is well-modeled by a power law plus a multicolor blackbody spectrum with peak temperature approximately equals 150-200 eV. The RXTE data sets also show evidence of an Fe line with equivalent widths approximately equal to 20-1OO eV. Reflection models show a hardening of the RXTE spectra with decreasing X-ray flux; however, these models do not exhibit evidence of a correlation between the photon index of the incident power law flux and the solid angle subtended by the reflector. 'Sphere+disk' Comptonization models and Advection Dominated Accretion Flow (ADAF) models also provide reasonable descriptions of the RXTE data. The former models yield coronal temperatures in the range 20-50 keV and optical depths of r approximately equal to 3. The model fits to the X-ray data, however, do not simultaneously explain the observed radio properties. The most likely source of the radio flux is synchrotron emission from an extended outflow of extent greater than O(10 (exp7) GM/c2).

Research on Modelling of Aviation Piston Engine for the Hardware-in-the-loop Simulation

NASA Astrophysics Data System (ADS)

Yu, Bing; Shu, Wenjun; Bian, Wenchao

2016-11-01

In order to build the aero piston engine model which is real-time and accurate enough to operating conditions of the real engine for hardware in the loop simulation, the mean value model is studied. Firstly, the air-inlet model, the fuel model and the power-output model are established separately. Then, these sub models are combined and verified in MATLAB/SIMULINK. The results show that the model could reflect the steady-state and dynamic performance of aero engine, the errors between the simulation results and the bench test data are within the acceptable range. The model could be applied to verify the logic performance and control strategy of controller in the hardware-in-the-loop (HIL) simulation.

Economic assessment and energy model scenarios of municipal solid waste incineration and gas turbine hybrid dual-fueled cycles in Thailand

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

Udomsri, Seksan, E-mail: seksan.udomsri@energy.kth.s; Martin, Andrew R.; Fransson, Torsten H.

Finding environmentally benign methods related to sound municipal solid waste (MSW) management is of highest priority in Southeast Asia. It is very important to study new approaches which can reduce waste generation and simultaneously enhance energy recovery. One concrete example of particular significance is the concept of hybrid dual-fuel power plants featuring MSW and another high-quality fuel like natural gas. The hybrid dual-fuel cycles provide significantly higher electrical efficiencies than a composite of separate single-fuel power plant (standalone gas turbine combined cycle and MSW incineration). Although hybrid versions are of great importance for energy conversion from MSW, an economic assessmentmore » of these systems must be addressed for a realistic appraisal of these technologies. This paper aims to further examine an economic assessment and energy model analysis of different conversion technologies. Energy models are developed to further refine the expected potential of MSW incineration with regards to energy recovery and environmental issues. Results show that MSW incineration can play role for greenhouse gas reduction, energy recovery and waste management. In Bangkok, the electric power production via conventional incineration and hybrid power plants can cover 2.5% and 8% of total electricity consumption, respectively. The hybrid power plants have a relative short payback period (5 years) and can further reduce the CO{sub 2} levels by 3% in comparison with current thermal power plants.« less

Economic assessment and energy model scenarios of municipal solid waste incineration and gas turbine hybrid dual-fueled cycles in Thailand.

PubMed

Udomsri, Seksan; Martin, Andrew R; Fransson, Torsten H

2010-07-01

Finding environmentally benign methods related to sound municipal solid waste (MSW) management is of highest priority in Southeast Asia. It is very important to study new approaches which can reduce waste generation and simultaneously enhance energy recovery. One concrete example of particular significance is the concept of hybrid dual-fuel power plants featuring MSW and another high-quality fuel like natural gas. The hybrid dual-fuel cycles provide significantly higher electrical efficiencies than a composite of separate single-fuel power plant (standalone gas turbine combined cycle and MSW incineration). Although hybrid versions are of great importance for energy conversion from MSW, an economic assessment of these systems must be addressed for a realistic appraisal of these technologies. This paper aims to further examine an economic assessment and energy model analysis of different conversion technologies. Energy models are developed to further refine the expected potential of MSW incineration with regards to energy recovery and environmental issues. Results show that MSW incineration can play role for greenhouse gas reduction, energy recovery and waste management. In Bangkok, the electric power production via conventional incineration and hybrid power plants can cover 2.5% and 8% of total electricity consumption, respectively. The hybrid power plants have a relative short payback period (5 years) and can further reduce the CO(2) levels by 3% in comparison with current thermal power plants. Copyright (c) 2010 Elsevier Ltd. All rights reserved.

Energy harvesting with stacked dielectric elastomer transducers: Nonlinear theory, optimization, and linearized scaling law

NASA Astrophysics Data System (ADS)

Tutcuoglu, A.; Majidi, C.

2014-12-01

Using principles of damped harmonic oscillation with continuous media, we examine electrostatic energy harvesting with a "soft-matter" array of dielectric elastomer (DE) transducers. The array is composed of infinitely thin and deformable electrodes separated by layers of insulating elastomer. During vibration, it deforms longitudinally, resulting in a change in the capacitance and electrical enthalpy of the charged electrodes. Depending on the phase of electrostatic loading, the DE array can function as either an actuator that amplifies small vibrations or a generator that converts these external excitations into electrical power. Both cases are addressed with a comprehensive theory that accounts for the influence of viscoelasticity, dielectric breakdown, and electromechanical coupling induced by Maxwell stress. In the case of a linearized Kelvin-Voigt model of the dielectric, we obtain a closed-form estimate for the electrical power output and a scaling law for DE generator design. For the complete nonlinear model, we obtain the optimal electrostatic voltage input for maximum electrical power output.

Combined Power Generation and Carbon Sequestration Using Direct FuelCell

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

Hossein Ghezel-Ayagh

2006-03-01

The unique chemistry of carbonate fuel cell offers an innovative approach for separation of carbon dioxide from greenhouse gases (GHG). The carbonate fuel cell system also produces electric power at high efficiency. The simultaneous generation of power and sequestration of greenhouse gases offer an attractive scenario for re-powering the existing coal-fueled power plants, in which the carbonate fuel cell would separate the carbon dioxide from the flue gas and would generate additional pollutant-free electric power. Development of this system is concurrent with emergence of Direct FuelCell{reg_sign} (DFC{reg_sign}) technology for generation of electric power from fossil fuels. DFC is based onmore » carbonate fuel cell featuring internal reforming. This technology has been deployed in MW-scale power plants and is readily available as a manufactured product. This final report describes the results of the conceptualization study conducted to assess the DFC-based system concept for separation of CO2 from GHG. Design and development studies were focused on integration of the DFC systems with coal-based power plants, which emit large amounts of GHG. In parallel to the system design and simulation activities, operation of laboratory scale DFC verified the technical concept and provided input to the design activity. The system was studied to determine its effectiveness in capturing more than ninety percent of CO2 from the flue gases. Cost analysis was performed to estimate the change in cost of electricity for a 200 MW pulverized coal boiler steam cycle plant retrofitted with the DFC-based CO2 separation system producing an additional 127 MW of electric power. The cost increments as percentage of levelized cost of electricity were estimated for a range of separation plant installations per year and a range of natural gas cost. The parametric envelope meeting the goal (<20% increase in COE) was identified. Results of this feasibility study indicated that DFC-based separation systems have the potential for capturing at least 90% of the emissions from the greenhouse gases generated by power plants and other industrial exhaust streams, and yet entail in less than 20% increase in the cost of energy services for long-term deployment (beyond 2012). The anticipated cost of energy increase is in line with DOE's goal for post-combustion systems as outlined in the ''Carbon Capture and Sequestration Systems Analysis Guidelines'', published by NETL, April 2005. During the course of this study certain enabling technologies were identified and the needs for further research and development were discussed.« less

Using the adsorption chillers for waste heat utilisation from the CCS installation

NASA Astrophysics Data System (ADS)

Sztekler, Karol; Kalawa, Wojciech; Nowak, Wojciech; Stefański, Sebastian; Krzywański, Jarosław; Grabowska, Karolina

2018-06-01

Worldwide tendencies in the scope of environmental protection demonstrate the requirement for the limited carbon dioxide emission, that influences on the development of greenhouse effect. As a result of coal as a basic fuel used in the professional power industry, this industry sector is the greatest CO2 polluter and it means that works on the reduction of carbon dioxide in such industry are completely justified. In the IPSEpro programming environment, a reference block model for a conventional coal power station was elaborated, including the CO2 separation unit basing on the adsorption methods with the CO2 preparation installation to liquid state. Simulation researches were conducted with means of numeric techniques, that enabled the system analysis for the CO2 separation unit with the CO2 preparation system to the liquid state, as well as analysis was made for the use of chiller systems, basing on the adsorption technology for waste heat use originating from the compression of CO2 in a cascade system, as well as for potential opportunities for further exploitation of the produced chilled water in the CCS cycle. We analysed in these papers the opportunities for chiller systems application, based on the adsorption chillers in the CCS installation used for the reduction of CO2 emission in the coal power station and its influence on the operation of a power station cycle.

Pressure and heat-transfer distributions in a simulated wing-elevon cove with variable leakage at a free-stream Mach number of 6.9

NASA Technical Reports Server (NTRS)

Deveikis, W. D.; Bartlett, W.

1978-01-01

An experimental aerodynamic heating investigation was conducted to determine effects of hot boundary-layer ingestion into the cove on the windward surface between a wing and elevon for cove seal leak areas nominally between 0 and 100 percent of cove entrance area. Pressure and heating-rate distributions were obtained on the wing and elevon surfaces and on the cove walls of a full-scale model that represented a section of the cove region on the space shuttle orbiter. Data were obtained for both attached and separated turbulent boundary layers upstream of the unswept cove entrance. Average free-stream Mach number was 6.9, average free-stream unit Reynolds numbers were 1.31 x 10 to the 6th power and 4.40 x 10 to the 6th power per meter (0.40 x 10 to the 6th power and 1.34 x 10 to the 6th power per foot), and average total temperature was 1888 K (3400 R). Cove pressures and heating rates varied as a function of seal leak area independent of leak aspect ratio. Although cove heating rates for attached flow did not appear intolerable, it was postulated that convective heating in the cove may increase with time. For separated flow, the cove environment was considered too severe for unprotected interior structures of control surfaces.

Simultaneous separation and purification of (-)-epigallocatechin gallate and caffeine from tea extract by size exclusion effect on modified porous adsorption material.

PubMed

Zhang, Xiaofeng; Xu, Yi; Zhang, Qing; Cao, Kun; Mu, Xiuni

2016-09-15

A dual-task method for the simultaneous separation and purification of (-)-epigallocatechin gallate (EGCG) and caffeine (CAF) from crude extract of green tea was established by size exclusion effect onto hydroquinone modified porous adsorbents. The results showed that hydroquinone modified porous adsorbents P4 provided the best separation power due to it has more porous structure and phenolic hydroxyl group. The adsorption-desorption behaviors of EGCG and CAF onto P4 adsorbents were investigated. Adsorption kinetics of EGCG and CAF results showed that the adsorption followed the pseudo-second-order kinetic model. The results also indicated that the equilibrium adsorption data best fit the Langmuir model. Meanwhile, EGCG and CAF were separated successfully onto P4 adsorbents packed columns in a gradient eluent process, and P4 adsorbents exhibited the size exclusion effect for small molecules CAF. Based on the phenolic hydroxyl group and size exclusion effect of P4 adsorbents, the high purity EGCG and CAF were obtained with 40% (v/v) ethanol eluent successively. The process fulfilled the task of simultaneous separation and purification of EGCG and CAF, and proved to be a promising basis for preparations of difficult to obtain active components that have similar polarity and different sizes of molecules and derived from the same natural products. Copyright © 2016 Elsevier B.V. All rights reserved.

Mach 10 Stage Separation Analysis for the X43-A

NASA Technical Reports Server (NTRS)

Tartabini, Paul V.; Bose, David M.; Thornblom, Mark N.; Lien, J. P.; Martin, John G.

2007-01-01

This paper describes the pre-flight stage separation analysis that was conducted in support of the final flight of the X-43A. In that flight, which occurred less than eight months after the successful Mach 7 flight, the X-43A Research Vehicle attained a peak speed of Mach 9.6. Details are provided on how the lessons learned from the Mach 7 flight affected separation modeling and how adjustments were made to account for the increased flight Mach number. Also, the procedure for defining the feedback loop closure and feed-forward parameters employed in the separation control logic are described, and their effect on separation performance is explained. In addition, the range and nominal values of these parameters, which were included in the Mission Data Load, are presented. Once updates were made, the nominal pre-flight trajectory and Monte Carlo statistical results were determined and stress tests were performed to ensure system robustness. During flight the vehicle performed within the uncertainty bounds predicted in the pre-flight analysis and ultimately set the world record for airbreathing powered flight.

Development of a three-dimensional transient code for reactivity-initiated events of BWRs (boiling water reactors) - Models and code verifications

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

Uematsu, Hitoshi; Yamamoto, Toru; Izutsu, Sadayuki

1990-06-01

A reactivity-initiated event is a design-basis accident for the safety analysis of boiling water reactors. It is defined as a rapid transient of reactor power caused by a reactivity insertion of over $1.0 due to a postulated drop or abnormal withdrawal of the control rod from the core. Strong space-dependent feedback effects are associated with the local power increase due to control rod movement. A realistic treatment of the core status in a transient by a code with a detailed core model is recommended in evaluating this event. A three-dimensional transient code, ARIES, has been developed to meet this need.more » The code simulates the event with three-dimensional neutronics, coupled with multichannel thermal hydraulics, based on a nonequilibrium separated flow model. The experimental data obtained in reactivity accident tests performed with the SPERT III-E core are used to verify the entire code, including thermal-hydraulic models.« less

Constraining Polarized Foregrounds for EoR Experiments. II. Polarization Leakage Simulations in the Avoidance Scheme

NASA Astrophysics Data System (ADS)

Nunhokee, C. D.; Bernardi, G.; Kohn, S. A.; Aguirre, J. E.; Thyagarajan, N.; Dillon, J. S.; Foster, G.; Grobler, T. L.; Martinot, J. Z. E.; Parsons, A. R.

2017-10-01

A critical challenge in the observation of the redshifted 21 cm line is its separation from bright Galactic and extragalactic foregrounds. In particular, the instrumental leakage of polarized foregrounds, which undergo significant Faraday rotation as they propagate through the interstellar medium, may harmfully contaminate the 21 cm power spectrum. We develop a formalism to describe the leakage due to instrumental widefield effects in visibility-based power spectra measured with redundant arrays, extending the delay-spectrum approach presented in Parsons et al. We construct polarized sky models and propagate them through the instrument model to simulate realistic full-sky observations with the Precision Array to Probe the Epoch of Reionization. We find that the leakage due to a population of polarized point sources is expected to be higher than diffuse Galactic polarization at any k mode for a 30 m reference baseline. For the same reference baseline, a foreground-free window at k > 0.3 h Mpc-1 can be defined in terms of leakage from diffuse Galactic polarization even under the most pessimistic assumptions. If measurements of polarized foreground power spectra or a model of polarized foregrounds are given, our method is able to predict the polarization leakage in actual 21 cm observations, potentially enabling its statistical subtraction from the measured 21 cm power spectrum.

Research and development studies for MHD/coal power flow train components. Technical progress report, 1 September 1979-31 August 1980

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

Bloom, M. H.

1980-01-01

The aim of this program is to contribute to certain facets of the development of the MHD/coal power system, and particularly the CDIF of DOE with regard to its flow train. Consideration is given specifically to the electrical power take-off, the diagnostic and instrumentation systems, the combustor and MHD channel technology, and electrode alternatives. Within the constraints of the program, high priorities were assigned to the problems of power take-off and the related characteristics of the MHD channel, and to the establishment of a non-intrusive, laser-based diagnostic system. The next priority was given to the combustor modeling and to amore » significantly improved analysis of particle combustion. Separate abstracts were prepared for nine of the ten papers included. One paper was previously included in the data base. (WHK)« less

Life Prediction Model for Grid-Connected Li-ion Battery Energy Storage System: Preprint

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

Smith, Kandler A; Saxon, Aron R; Keyser, Matthew A

Life Prediction Model for Grid-Connected Li-ion Battery Energy Storage System: Preprint Lithium-ion (Li-ion) batteries are being deployed on the electrical grid for a variety of purposes, such as to smooth fluctuations in solar renewable power generation. The lifetime of these batteries will vary depending on their thermal environment and how they are charged and discharged. To optimal utilization of a battery over its lifetime requires characterization of its performance degradation under different storage and cycling conditions. Aging tests were conducted on commercial graphite/nickel-manganese-cobalt (NMC) Li-ion cells. A general lifetime prognostic model framework is applied to model changes in capacity andmore » resistance as the battery degrades. Across 9 aging test conditions from 0oC to 55oC, the model predicts capacity fade with 1.4 percent RMS error and resistance growth with 15 percent RMS error. The model, recast in state variable form with 8 states representing separate fade mechanisms, is used to extrapolate lifetime for example applications of the energy storage system integrated with renewable photovoltaic (PV) power generation.« less

A perturbative approach to the redshift space correlation function: beyond the Standard Model

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

Bose, Benjamin; Koyama, Kazuya, E-mail: benjamin.bose@port.ac.uk, E-mail: kazuya.koyama@port.ac.uk

We extend our previous redshift space power spectrum code to the redshift space correlation function. Here we focus on the Gaussian Streaming Model (GSM). Again, the code accommodates a wide range of modified gravity and dark energy models. For the non-linear real space correlation function used in the GSM we use the Fourier transform of the RegPT 1-loop matter power spectrum. We compare predictions of the GSM for a Vainshtein screened and Chameleon screened model as well as GR. These predictions are compared to the Fourier transform of the Taruya, Nishimichi and Saito (TNS) redshift space power spectrum model whichmore » is fit to N-body data. We find very good agreement between the Fourier transform of the TNS model and the GSM predictions, with ≤ 6% deviations in the first two correlation function multipoles for all models for redshift space separations in 50Mpc h ≤ s ≤ 180Mpc/ h . Excellent agreement is found in the differences between the modified gravity and GR multipole predictions for both approaches to the redshift space correlation function, highlighting their matched ability in picking up deviations from GR. We elucidate the timeliness of such non-standard templates at the dawn of stage-IV surveys and discuss necessary preparations and extensions needed for upcoming high quality data.« less

Isotope Separation in Concurrent Gas Centrifuges

NASA Astrophysics Data System (ADS)

Bogovalov, S. V.; Borman, V. D.

An analytical equation defining separative power of an optimized concurrent gas centrifuge is obtained for an arbitrary binary mixture of isotopes. In the case of the uranium isotopes the equation gives δU= 12.7(V/700 m/s)2(300 K/T)L, kg SWU/yr, where L and V are the length and linear velocity of the rotor of the gas centrifuge, T is the temperature. This formula well agrees with an empirical separative power of counter current gas centrifuges.

Aerodynamics of powered missile separation from a wing

NASA Technical Reports Server (NTRS)

Shanks, S. P.; Ahmad, J. U.

1991-01-01

A 3D dynamic 'chimera' algorithm that solves the thin-layer Navier-Stokes equations over multiple moving bodies was modified to numerically simulate the aerodynamics, missile dynamics, and missile plume of a finless missile separating from a wing in transonic flow. A powered missile separation case was considered to examine the influence of the missile and plume on the wing. The wing and missile is at a two degree angle of attack. The computational results show the details of the flow field.

The Emerging Role of the Republic of South Africa as a Regional Power

DTIC Science & Technology

2003-04-07

effect national power. It is written from the perspective that South Africa, even with its past of racial separation and minority rule, is overcoming...facing these issues head-on, has overcome racial diverseness, and is developing into a leading regional role. South Africa is transforming. Since 1994...that effect national power. It is written from the perspective that South Africa, even with its past of racial separation and minority rule, is

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

Tang, Yingying; Homer, Juliet S.; McDermott, Thomas E.

The purpose of this document is to summarize types of electric distribution system analyses along with their application and relative maturity. Particular emphasis is placed on analyses associated with distributed energy resources (DERs). Analyses are separated into the categories of power flow, power quality, fault analysis, dynamic analysis and market analysis. Studies associated with DERs are called out in a separate section.

Regional Interagency Commands: A Whole of Government Structure for Complex Operations

DTIC Science & Technology

2010-03-01

testimony/- 111thCongress/04_30_2009.asp (accessed 21 Mar 2010). 51 Charles R. Kesler, “What Separation of Powers Means for Constitutional Government”, 17...Dec 2007, http://www.heritage.org/Research/Reports/2007/12/What- Separation - of - Powers -Means-for-Constitutional-Government#_ftnref13 (accessed 29 Dec

Undeclared Wars: The Packaging of a National Security Strategy for the 1990’s

DTIC Science & Technology

1994-04-01

regarding shared or separation of powers between the executive and legislature. The issue became less of which branch of government was going to approve... separation of powers " in using military force in non-traditional roles can be found in the Constitution, as articulated by the Founding Fathers. 56

12 CFR 550.250 - Must I keep fiduciary assets separate from other assets?

Code of Federal Regulations, 2010 CFR

2010-01-01

... 12 Banks and Banking 5 2010-01-01 2010-01-01 false Must I keep fiduciary assets separate from other assets? 550.250 Section 550.250 Banks and Banking OFFICE OF THRIFT SUPERVISION, DEPARTMENT OF THE TREASURY FIDUCIARY POWERS OF SAVINGS ASSOCIATIONS Exercising Fiduciary Powers Custody and Control of Assets...

12 CFR 550.430 - Must I keep fiduciary records separate and distinct from other records?

Code of Federal Regulations, 2010 CFR

2010-01-01

... 12 Banks and Banking 5 2010-01-01 2010-01-01 false Must I keep fiduciary records separate and distinct from other records? 550.430 Section 550.430 Banks and Banking OFFICE OF THRIFT SUPERVISION, DEPARTMENT OF THE TREASURY FIDUCIARY POWERS OF SAVINGS ASSOCIATIONS Exercising Fiduciary Powers Recordkeeping...

12 CFR 550.430 - Must I keep fiduciary records separate and distinct from other records?

Code of Federal Regulations, 2011 CFR

2011-01-01

... 12 Banks and Banking 5 2011-01-01 2011-01-01 false Must I keep fiduciary records separate and distinct from other records? 550.430 Section 550.430 Banks and Banking OFFICE OF THRIFT SUPERVISION, DEPARTMENT OF THE TREASURY FIDUCIARY POWERS OF SAVINGS ASSOCIATIONS Exercising Fiduciary Powers Recordkeeping...

12 CFR 550.250 - Must I keep fiduciary assets separate from other assets?

Code of Federal Regulations, 2011 CFR

2011-01-01

... 12 Banks and Banking 5 2011-01-01 2011-01-01 false Must I keep fiduciary assets separate from other assets? 550.250 Section 550.250 Banks and Banking OFFICE OF THRIFT SUPERVISION, DEPARTMENT OF THE TREASURY FIDUCIARY POWERS OF SAVINGS ASSOCIATIONS Exercising Fiduciary Powers Custody and Control of Assets...

Inductive Sensor Performance in Partial Discharges and Noise Separation by Means of Spectral Power Ratios

PubMed Central

Ardila-Rey, Jorge Alfredo; Rojas-Moreno, Mónica Victoria; Martínez-Tarifa, Juan Manuel; Robles, Guillermo

2014-01-01

Partial discharge (PD) detection is a standardized technique to qualify electrical insulation in machines and power cables. Several techniques that analyze the waveform of the pulses have been proposed to discriminate noise from PD activity. Among them, spectral power ratio representation shows great flexibility in the separation of the sources of PD. Mapping spectral power ratios in two-dimensional plots leads to clusters of points which group pulses with similar characteristics. The position in the map depends on the nature of the partial discharge, the setup and the frequency response of the sensors. If these clusters are clearly separated, the subsequent task of identifying the source of the discharge is straightforward so the distance between clusters can be a figure of merit to suggest the best option for PD recognition. In this paper, two inductive sensors with different frequency responses to pulsed signals, a high frequency current transformer and an inductive loop sensor, are analyzed to test their performance in detecting and separating the sources of partial discharges. PMID:24556674

Heterotic computing: exploiting hybrid computational devices.

PubMed

Kendon, Viv; Sebald, Angelika; Stepney, Susan

2015-07-28

Current computational theory deals almost exclusively with single models: classical, neural, analogue, quantum, etc. In practice, researchers use ad hoc combinations, realizing only recently that they can be fundamentally more powerful than the individual parts. A Theo Murphy meeting brought together theorists and practitioners of various types of computing, to engage in combining the individual strengths to produce powerful new heterotic devices. 'Heterotic computing' is defined as a combination of two or more computational systems such that they provide an advantage over either substrate used separately. This post-meeting collection of articles provides a wide-ranging survey of the state of the art in diverse computational paradigms, together with reflections on their future combination into powerful and practical applications. © 2015 The Author(s) Published by the Royal Society. All rights reserved.

Simultaneous Microwave Extraction and Separation of Volatile and Non-Volatile Organic Compounds of Boldo Leaves. From Lab to Industrial Scale

PubMed Central

Petigny, Loïc; Périno, Sandrine; Minuti, Matteo; Visinoni, Francesco; Wajsman, Joël; Chemat, Farid

2014-01-01

Microwave extraction and separation has been used to increase the concentration of the extract compared to the conventional method with the same solid/liquid ratio, reducing extraction time and separate at the same time Volatile Organic Compounds (VOC) from non-Volatile Organic Compounds (NVOC) of boldo leaves. As preliminary study, a response surface method has been used to optimize the extraction of soluble material and the separation of VOC from the plant in laboratory scale. The results from the statistical analysis revealed that the optimized conditions were: microwave power 200 W, extraction time 56 min and solid liquid ratio of 7.5% of plants in water. Lab scale optimized microwave method is compared to conventional distillation, and requires a power/mass ratio of 0.4 W/g of water engaged. This power/mass ratio is kept in order to upscale from lab to pilot plant. PMID:24776762

Research on Separation of Three Powers Architecture for Trusted OS

NASA Astrophysics Data System (ADS)

Li, Yu; Zhao, Yong; Xin, Siyuan

The privilege in the operating system (OS) often results in the break of confidentiality and integrity of the system. To solve this problem, several security mechanisms are proposed, such as Role-based Access Control, Separation of Duty. However, these mechanisms can not eliminate the privilege in OS kernel layer. This paper proposes a Separation of Three Powers Architecture (STPA). The authorizations in OS are divided into three parts: System Management Subsystem (SMS), Security Management Subsystem (SEMS) and Audit Subsystem (AS). Mutual support and mutual checks and balances which are the design principles of STPA eliminate the administrator in the kernel layer. Furthermore, the paper gives the formal description for authorization division using the graph theory. Finally, the implementation of STPA is given. Proved by experiments, the Separation of Three Powers Architecture we proposed can provide reliable protection for the OS through authorization division.

Study on the hydraulic characteristics of side inlet/outlet by physical model test

NASA Astrophysics Data System (ADS)

Kong, Bo; Ye, Fei; Hu, Qiu-yue; Zhang, Jing

2017-04-01

The hydraulic characteristics at the side inlet/outlet of pumped storage plants were studied by physical model test. The gravity similarity rule was adopted and head loss coefficients under pumped and power conditions were given. The flow distribution under both conditions was studied. Scheme of changing the separation pier section area proportion for minimizing velocity uneven coefficient was brought forward and the cause of test error was researched. Vortex evaluation and observation were studied under the pumped condition at normal and dead reservoir water levels.

Lightning protection of distribution lines

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

McDermott, T.E.; Short, T.A.; Anderson, J.G.

1994-01-01

This paper reports a study of distribution line lightning performance, using computer simulations of lightning overvoltages. The results of previous investigations are extended with a detailed model of induced voltages from nearby strokes, coupled into a realistic power system model. The paper also considers the energy duty of distribution-class surge arresters exposed to direct strokes. The principal result is that widely separated pole-top arresters can effectively protect a distribution line from induced-voltage flashovers. This means that nearby lightning strokes need not be a significant lightning performance problem for most distribution lines.

Statistical 21-cm Signal Separation via Gaussian Process Regression Analysis

NASA Astrophysics Data System (ADS)

Mertens, F. G.; Ghosh, A.; Koopmans, L. V. E.

2018-05-01

Detecting and characterizing the Epoch of Reionization and Cosmic Dawn via the redshifted 21-cm hyperfine line of neutral hydrogen will revolutionize the study of the formation of the first stars, galaxies, black holes and intergalactic gas in the infant Universe. The wealth of information encoded in this signal is, however, buried under foregrounds that are many orders of magnitude brighter. These must be removed accurately and precisely in order to reveal the feeble 21-cm signal. This requires not only the modeling of the Galactic and extra-galactic emission, but also of the often stochastic residuals due to imperfect calibration of the data caused by ionospheric and instrumental distortions. To stochastically model these effects, we introduce a new method based on `Gaussian Process Regression' (GPR) which is able to statistically separate the 21-cm signal from most of the foregrounds and other contaminants. Using simulated LOFAR-EoR data that include strong instrumental mode-mixing, we show that this method is capable of recovering the 21-cm signal power spectrum across the entire range k = 0.07 - 0.3 {h cMpc^{-1}}. The GPR method is most optimal, having minimal and controllable impact on the 21-cm signal, when the foregrounds are correlated on frequency scales ≳ 3 MHz and the rms of the signal has σ21cm ≳ 0.1 σnoise. This signal separation improves the 21-cm power-spectrum sensitivity by a factor ≳ 3 compared to foreground avoidance strategies and enables the sensitivity of current and future 21-cm instruments such as the Square Kilometre Array to be fully exploited.

Wireless power transfer based on dielectric resonators with colossal permittivity

NASA Astrophysics Data System (ADS)

Song, Mingzhao; Belov, Pavel; Kapitanova, Polina

2016-11-01

Magnetic resonant wireless power transfer system based on dielectric disk resonators made of colossal permittivity (ɛ = 1000) and low loss (tan δ = 2.5 × 10-4) microwave ceramic is experimentally investigated. The system operates at the magnetic dipole mode excited in the resonators providing maximal power transfer efficiency of 90% at the frequency 232 MHz. By applying an impedance matching technique, the efficiency of 50% is achieved within the separation between the resonators d = 16 cm (3.8 radii of the resonator). The separation, misalignment and rotation dependencies of wireless power transfer efficiency are experimentally studied.

The Wind Forecast Improvement Project (WFIP). A Public/Private Partnership for Improving Short Term Wind Energy Forecasts and Quantifying the Benefits of Utility Operations -- the Northern Study Area

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

Finley, Cathy

2014-04-30

This report contains the results from research aimed at improving short-range (0-6 hour) hub-height wind forecasts in the NOAA weather forecast models through additional data assimilation and model physics improvements for use in wind energy forecasting. Additional meteorological observing platforms including wind profilers, sodars, and surface stations were deployed for this study by NOAA and DOE, and additional meteorological data at or near wind turbine hub height were provided by South Dakota State University and WindLogics/NextEra Energy Resources over a large geographical area in the U.S. Northern Plains for assimilation into NOAA research weather forecast models. The resulting improvements inmore » wind energy forecasts based on the research weather forecast models (with the additional data assimilation and model physics improvements) were examined in many different ways and compared with wind energy forecasts based on the current operational weather forecast models to quantify the forecast improvements important to power grid system operators and wind plant owners/operators participating in energy markets. Two operational weather forecast models (OP_RUC, OP_RAP) and two research weather forecast models (ESRL_RAP, HRRR) were used as the base wind forecasts for generating several different wind power forecasts for the NextEra Energy wind plants in the study area. Power forecasts were generated from the wind forecasts in a variety of ways, from very simple to quite sophisticated, as they might be used by a wide range of both general users and commercial wind energy forecast vendors. The error characteristics of each of these types of forecasts were examined and quantified using bulk error statistics for both the local wind plant and the system aggregate forecasts. The wind power forecast accuracy was also evaluated separately for high-impact wind energy ramp events. The overall bulk error statistics calculated over the first six hours of the forecasts at both the individual wind plant and at the system-wide aggregate level over the one year study period showed that the research weather model-based power forecasts (all types) had lower overall error rates than the current operational weather model-based power forecasts, both at the individual wind plant level and at the system aggregate level. The bulk error statistics of the various model-based power forecasts were also calculated by season and model runtime/forecast hour as power system operations are more sensitive to wind energy forecast errors during certain times of year and certain times of day. The results showed that there were significant differences in seasonal forecast errors between the various model-based power forecasts. The results from the analysis of the various wind power forecast errors by model runtime and forecast hour showed that the forecast errors were largest during the times of day that have increased significance to power system operators (the overnight hours and the morning/evening boundary layer transition periods), but the research weather model-based power forecasts showed improvement over the operational weather model-based power forecasts at these times.« less

Tunnelling magnetoresistance and 1/f noise in phase-separated manganites

NASA Astrophysics Data System (ADS)

Sboychakov, A. O.; Rakhmanov, A. L.; Kugel, K. I.; Kagan, M. Yu; Brodsky, I. V.

2003-03-01

The magnetoresistance and the noise power of non-metallic phase-separated manganites are studied. The material is modelled by a system of small ferromagnetic metallic droplets (magnetic polarons or ferrons) in an insulating matrix. The concentration of metallic phase is assumed to be far from the percolation threshold. The electron tunnelling between ferrons causes the charge transfer in such a system. The magnetoresistance is determined both by the increase in the volume of the metallic phase and by the change in the electron hopping probability. In the framework of such a model, the low-field magnetoresistance is proportional to H2 and decreases with temperature as T-n, where n can vary from 1 to 5, depending on the parameters of the system. In the high-field limit, the tunnelling magnetoresistance grows exponentially. Different mechanisms of the voltage fluctuations in the system are analysed. The noise spectrum generated by the fluctuations of the number of droplets with extra electrons has a 1/f form over a wide frequency range. In the case of strong magnetic anisotropy, the 1/f noise can also arise due to fluctuations of the magnetic moments of ferrons. The 1/f noise power depends only slightly on the magnetic field in the low field range whereas it can increase as H6 in the high-field limit.

An open-population hierarchical distance sampling model

USGS Publications Warehouse

Sollmann, Rachel; Beth Gardner,; Richard B Chandler,; Royle, J. Andrew; T Scott Sillett,

2015-01-01

Modeling population dynamics while accounting for imperfect detection is essential to monitoring programs. Distance sampling allows estimating population size while accounting for imperfect detection, but existing methods do not allow for direct estimation of demographic parameters. We develop a model that uses temporal correlation in abundance arising from underlying population dynamics to estimate demographic parameters from repeated distance sampling surveys. Using a simulation study motivated by designing a monitoring program for island scrub-jays (Aphelocoma insularis), we investigated the power of this model to detect population trends. We generated temporally autocorrelated abundance and distance sampling data over six surveys, using population rates of change of 0.95 and 0.90. We fit the data generating Markovian model and a mis-specified model with a log-linear time effect on abundance, and derived post hoc trend estimates from a model estimating abundance for each survey separately. We performed these analyses for varying number of survey points. Power to detect population changes was consistently greater under the Markov model than under the alternatives, particularly for reduced numbers of survey points. The model can readily be extended to more complex demographic processes than considered in our simulations. This novel framework can be widely adopted for wildlife population monitoring.

An open-population hierarchical distance sampling model.

PubMed

Sollmann, Rahel; Gardner, Beth; Chandler, Richard B; Royle, J Andrew; Sillett, T Scott

2015-02-01

Modeling population dynamics while accounting for imperfect detection is essential to monitoring programs. Distance sampling allows estimating population size while accounting for imperfect detection, but existing methods do not allow for estimation of demographic parameters. We develop a model that uses temporal correlation in abundance arising from underlying population dynamics to estimate demographic parameters from repeated distance sampling surveys. Using a simulation study motivated by designing a monitoring program for Island Scrub-Jays (Aphelocoma insularis), we investigated the power of this model to detect population trends. We generated temporally autocorrelated abundance and distance sampling data over six surveys, using population rates of change of 0.95 and 0.90. We fit the data generating Markovian model and a mis-specified model with a log-linear time effect on abundance, and derived post hoc trend estimates from a model estimating abundance for each survey separately. We performed these analyses for varying numbers of survey points. Power to detect population changes was consistently greater under the Markov model than under the alternatives, particularly for reduced numbers of survey points. The model can readily be extended to more complex demographic processes than considered in our simulations. This novel framework can be widely adopted for wildlife population monitoring.

Mitigating external and internal cathode fouling using a polymer bonded separator in microbial fuel cells.

PubMed

Yang, Wulin; Rossi, Ruggero; Tian, Yushi; Kim, Kyoung-Yeol; Logan, Bruce E

2018-02-01

Microbial fuel cell (MFC) cathodes rapidly foul when treating domestic wastewater, substantially reducing power production over time. Here a wipe separator was chemically bonded to an activated carbon air cathode using polyvinylidene fluoride (PVDF) to mitigate cathode fouling and extend cathode performance over time. MFCs with separator-bonded cathodes produced a maximum power density of 190 ± 30 mW m -2 after 2 months of operation using domestic wastewater, which was ∼220% higher than controls (60 ± 50 mW m -2 ) with separators that were not chemically bonded to the cathode. Less biomass (protein) was measured on the bonded separator surface than the non-bonded separator, indicating chemical bonding reduced external bio-fouling. Salt precipitation that contributed to internal fouling was also reduced using separator-bonded cathodes. Overall, the separator-bonded cathodes showed better performance over time by mitigating both external bio-fouling and internal salt fouling. Copyright © 2017 Elsevier Ltd. All rights reserved.

Advanced statistical energy analysis

NASA Astrophysics Data System (ADS)

Heron, K. H.

1994-09-01

A high-frequency theory (advanced statistical energy analysis (ASEA)) is developed which takes account of the mechanism of tunnelling and uses a ray theory approach to track the power flowing around a plate or a beam network and then uses statistical energy analysis (SEA) to take care of any residual power. ASEA divides the energy of each sub-system into energy that is freely available for transfer to other sub-systems and energy that is fixed within the sub-systems that are physically separate and can be interpreted as a series of mathematical models, the first of which is identical to standard SEA and subsequent higher order models are convergent on an accurate prediction. Using a structural assembly of six rods as an example, ASEA is shown to converge onto the exact results while SEA is shown to overpredict by up to 60 dB.

Competing phases, phase separation, and coexistence in the extended one-dimensional bosonic Hubbard model

DOE PAGES

Batrouni, G. G.; Rousseau, V. G.; Scalettar, R. T.; ...

2014-11-17

Here, we study the phase diagram of the one-dimensional bosonic Hubbard model with contact (U) and near neighbor (V ) interactions focusing on the gapped Haldane insulating (HI) phase which is characterized by an exotic nonlocal order parameter. The parameter regime (U, V and μ) where this phase exists and how it competes with other phases such as the supersolid (SS) phase, is incompletely understood. We use the Stochastic Green Function quantum Monte Carlo algorithm as well as the density matrix renormalization group to map out the phase diagram. The HI exists only at = 1, the SS phase existsmore » for a very wide range of parameters (including commensurate fillings) and displays power law decay in the one body Green function were our main conclusions. Additionally, we show that at fixed integer density, the system exhibits phase separation in the (U, V ) plane.« less

Shear velocity of the Rotokawa geothermal field using ambient noise

NASA Astrophysics Data System (ADS)

Civilini, F.; Savage, M. K.; Townend, J.

2014-12-01

Ambient noise correlation is an increasingly popular seismological technique that uses the ambient seismic noise recorded at two stations to construct an empirical Green's function. Applications of this technique include determining shear velocity structure and attenuation. An advantage of ambient noise is that it does not rely on external sources of seismic energy such as local or teleseismic earthquakes. This method has been used in the geothermal industry to determine the depths at which magmatic processes occur, to distinguish between production and non-production areas, and to observe seismic velocity perturbations associated with fluid extraction. We will present a velocity model for the Rotokawa geothermal field near Taupo, New Zealand, produced from ambient noise cross correlations. Production at Rotokawa is based on the "Rotokawa A" combined cycle power station established in 1997 and the "Nga Awa Purua" triple flash power plant established in 2010. Rotokawa Joint Venture, a partnership between Mighty River Power and Tauhara North No. 2 Trust currently operates 174 MW of generation at Rotokawa. An array of short period seismometers was installed in 2008 and occupies an area of roughly 5 square kilometers around the site. Although both cultural and natural noise sources are recorded at the stations, the instrument separation distance provides a unique challenge for analyzing cross correlations produced by both signal types. The inter-station spacing is on the order of a few kilometers, so waves from cultural sources generally are not coherent from one station to the other, while the wavelength produced by natural noise is greater than the station separation. Velocity models produced from these two source types will be compared to known geological models of the site. Depending on the amount of data needed to adequately construct cross-correlations, a time-dependent model of velocity will be established and compared with geothermal production processes.

An ammonium sulfate/ethanol aqueous two-phase system combined with ultrasonication for the separation and purification of lithospermic acid B from Salvia miltiorrhiza Bunge.

PubMed

Guo, Y X; Han, J; Zhang, D Y; Wang, L H; Zhou, L L

2012-07-01

We studied the effect of ultrasonication extraction technology combined with ammonium sulfate/ethanol aqueous two-phase system (ATPS) for the separation of lithospermic acid B (LAB) from Salvia miltiorrhiza Bunge. According to the literature and preliminary studies, ammonium sulfate concentration, ethanol concentration, pH, ultrasonication power, ultrasonication time and the ratio of solvent-to-solid were investigated using a single factor design to identify the factors affecting separation. Taking into consideration a simultaneous increase in LAB recovery (R (%)) and partition coefficient (K), the best performance of the ATPS was obtained at 25°C and pH 2 using ammonium sulfate 22% (w/w) and ethanol 30% (w/w). To keep the solvent-to-solid ratio at 10, response surface methodology was used to find the optimal ultrasonication power and ultrasonication time. Quadratic models were predicted for LAB yield in the upper phase. Optimal conditions of 572.1 W ultrasonication power and 42.2 min produced a maximum yield of LAB of 42.16 mg g(-1) sample. There was no obvious degradation of LAB with ultrasound under the applied conditions, and the experimental yield of LAB was 42.49 mg g(-1) sample and the purity was 55.28% (w/w), which was much higher than that obtained using conventional extraction. The present study demonstrated that ultrasound coupled with aqueous two-phase systems is very efficient tool for the extraction and purification of LAB from Salvia miltiorrhiza Bunge. Copyright © 2011 Elsevier B.V. All rights reserved.

RELAP5 Model of the First Wall/Blanket Primary Heat Transfer System

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

Popov, Emilian L; Yoder Jr, Graydon L; Kim, Seokho H

2010-06-01

ITER inductive power operation is modeled and simulated using a system level computer code to evaluate the behavior of the Primary Heat Transfer System (PHTS) and predict parameter operational ranges. The control algorithm strategy and derivation are summarized in this report as well. A major feature of ITER is pulsed operation. The plasma does not burn continuously, but the power is pulsed with large periods of zero power between pulses. This feature requires active temperature control to maintain a constant blanket inlet temperature and requires accommodation of coolant thermal expansion during the pulse. In view of the transient nature ofmore » the power (plasma) operation state a transient system thermal-hydraulics code was selected: RELAP5. The code has a well-documented history for nuclear reactor transient analyses, it has been benchmarked against numerous experiments, and a large user database of commonly accepted modeling practices exists. The process of heat deposition and transfer in the blanket modules is multi-dimensional and cannot be accurately captured by a one-dimensional code such as RELAP5. To resolve this, a separate CFD calculation of blanket thermal power evolution was performed using the 3-D SC/Tetra thermofluid code. A 1D-3D co-simulation more realistically models FW/blanket internal time-dependent thermal inertia while eliminating uncertainties in the time constant assumed in a 1-D system code. Blanket water outlet temperature and heat release histories for any given ITER pulse operation scenario are calculated. These results provide the basis for developing time dependent power forcing functions which are used as input in the RELAP5 calculations.« less

Striatal and Hippocampal Entropy and Recognition Signals in Category Learning: Simultaneous Processes Revealed by Model-Based fMRI

PubMed Central

Davis, Tyler; Love, Bradley C.; Preston, Alison R.

2012-01-01

Category learning is a complex phenomenon that engages multiple cognitive processes, many of which occur simultaneously and unfold dynamically over time. For example, as people encounter objects in the world, they simultaneously engage processes to determine their fit with current knowledge structures, gather new information about the objects, and adjust their representations to support behavior in future encounters. Many techniques that are available to understand the neural basis of category learning assume that the multiple processes that subserve it can be neatly separated between different trials of an experiment. Model-based functional magnetic resonance imaging offers a promising tool to separate multiple, simultaneously occurring processes and bring the analysis of neuroimaging data more in line with category learning’s dynamic and multifaceted nature. We use model-based imaging to explore the neural basis of recognition and entropy signals in the medial temporal lobe and striatum that are engaged while participants learn to categorize novel stimuli. Consistent with theories suggesting a role for the anterior hippocampus and ventral striatum in motivated learning in response to uncertainty, we find that activation in both regions correlates with a model-based measure of entropy. Simultaneously, separate subregions of the hippocampus and striatum exhibit activation correlated with a model-based recognition strength measure. Our results suggest that model-based analyses are exceptionally useful for extracting information about cognitive processes from neuroimaging data. Models provide a basis for identifying the multiple neural processes that contribute to behavior, and neuroimaging data can provide a powerful test bed for constraining and testing model predictions. PMID:22746951

Numerical investigation of the electric field distribution and the power deposition in the resonant cavity of a microwave electrothermal thruster

NASA Astrophysics Data System (ADS)

Yildiz, Mehmet Serhan; Celik, Murat

2017-04-01

Microwave electrothermal thruster (MET), an in-space propulsion concept, uses an electromagnetic resonant cavity as a heating chamber. In a MET system, electromagnetic energy is converted to thermal energy via a free floating plasma inside a resonant cavity. To optimize the power deposition inside the cavity, the factors that affect the electric field distribution and the resonance conditions must be accounted for. For MET thrusters, the length of the cavity, the dielectric plate that separates the plasma zone from the antenna, the antenna length and the formation of a free floating plasma have direct effects on the electromagnetic wave transmission and thus the power deposition. MET systems can be tuned by adjusting the lengths of the cavity or the antenna. This study presents the results of a 2-D axis symmetric model for the investigation of the effects of cavity length, antenna length, separation plate thickness, as well as the presence of free floating plasma on the power absorption. Specifically, electric field distribution inside the resonant cavity is calculated for a prototype MET system developed at the Bogazici University Space Technologies Laboratory. Simulations are conducted for a cavity fed with a constant power input of 1 kW at 2.45 GHz using COMSOL Multiphysics commercial software. Calculations are performed for maximum plasma electron densities ranging from 1019 to 1021 #/m3. It is determined that the optimum antenna length changes with changing plasma density. The calculations show that over 95% of the delivered power can be deposited to the plasma when the system is tuned by adjusting the cavity length.

A Power Hardware-in-the-Loop Platform with Remote Distribution Circuit Cosimulation

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

Palmintier, Bryan; Lundstrom, Blake; Chakraborty, Sudipta

2015-04-01

This paper demonstrates the use of a novel cosimulation architecture that integrates hardware testing using Power Hardware-in-the-Loop (PHIL) with larger-scale electric grid models using off-the-shelf, non-PHIL software tools. This architecture enables utilities to study the impacts of emerging energy technologies on their system and manufacturers to explore the interactions of new devices with existing and emerging devices on the power system, both without the need to convert existing grid models to a new platform or to conduct in-field trials. The paper describes an implementation of this architecture for testing two residential-scale advanced solar inverters at separate points of common coupling.more » The same hardware setup is tested with two different distribution feeders (IEEE 123 and 8500 node test systems) modeled using GridLAB-D. In addition to simplifying testing with multiple feeders, the architecture demonstrates additional flexibility with hardware testing in one location linked via the Internet to software modeling in a remote location. In testing, inverter current, real and reactive power, and PCC voltage are well captured by the co-simulation platform. Testing of the inverter advanced control features is currently somewhat limited by the software model time step (1 sec) and tested communication latency (24 msec). Overshoot induced oscillations are observed with volt/VAR control delays of 0 and 1.5 sec, while 3.4 sec and 5.5 sec delays produced little or no oscillation. These limitations could be overcome using faster modeling and communication within the same co-simulation architecture.« less

The Consitituion as a Bill of Rights: Separation of Powers and Individual Liberty.

ERIC Educational Resources Information Center

Meese, Edwin, III

One of the basic principles of the Constitution--the separation of powers--and its contribution to the preservation and perpetuation of individual liberty is discussed. To renew public appreciation of the Constitution, our fundamental law and the philosophical foundation of our political order, is the most fitting bicentennial celebration U.S.…

Power and Energy Systems Technology Program. Research Series No. 43.

ERIC Educational Resources Information Center

Haakenson, Harvey

The overall objective of this project was to develop a training program and materials for power plant training in North Dakota. The project utilized four separate instructional units and four separate enrollment times with eight students enrolling in each phase to a maximum of thirty-two students. The course that resulted from the project is…

10 CFR 2.402 - Separate hearings on separate issues; consolidation of proceedings.

Code of Federal Regulations, 2010 CFR

2010-01-01

... appendix N of part 50 of this chapter for construction permits for nuclear power reactors of a type... Licenses To Construct and/or Operate Nuclear Power Plants of Identical Design at Multiple Sites § 2.402... proceedings. 2.402 Section 2.402 Energy NUCLEAR REGULATORY COMMISSION RULES OF PRACTICE FOR DOMESTIC LICENSING...

The introspective may achieve more: Enhancing existing Geoscientific models with native-language emulated structural reflection

NASA Astrophysics Data System (ADS)

Ji, Xinye; Shen, Chaopeng

2018-01-01

Geoscientific models manage myriad and increasingly complex data structures as trans-disciplinary models are integrated. They often incur significant redundancy with cross-cutting tasks. Reflection, the ability of a program to inspect and modify its structure and behavior at runtime, is known as a powerful tool to improve code reusability, abstraction, and separation of concerns. Reflection is rarely adopted in high-performance Geoscientific models, especially with Fortran, where it was previously deemed implausible. Practical constraints of language and legacy often limit us to feather-weight, native-language solutions. We demonstrate the usefulness of a structural-reflection-emulating, dynamically-linked metaObjects, gd. We show real-world examples including data structure self-assembly, effortless input/output (IO) and upgrade to parallel I/O, recursive actions and batch operations. We share gd and a derived module that reproduces MATLAB-like structure in Fortran and C++. We suggest that both a gd representation and a Fortran-native representation are maintained to access the data, each for separate purposes. Embracing emulated reflection allows generically-written codes that are highly re-usable across projects.

Cationic permethylated 6-monoamino-6-monodeoxy-β-cyclodextrin as chiral selector of dansylated amino acids in capillary electrophoresis.

PubMed

Németh, Krisztina; Domonkos, Celesztina; Sarnyai, Virág; Szemán, Julianna; Jicsinszky, László; Szente, Lajos; Visy, Júlia

2014-10-01

The resolution power of permethylated 6-monoamino-6-monodeoxy-βCD (PMMABCD) - a single isomer, cationic CD derivative - developed previously for chiral analyses in capillary electrophoresis was further studied here. Dansylated amino acids (Dns-AA) were chosen as amphoteric chiral model compounds. Changes in the resolutions of Dns-AAs by varying pH and selector concentrations were investigated and correlated with their structures and chemical properties (isoelectric point and lipophilicity). Maximal resolutions could be achieved at pH 6 or pH 4. The separations improved with increasing concentration of the selector. Baseline or substantially better resolution for 8 pairs of these Dns-AAs could be achieved. Low CD concentration was enough for the separation of the most apolar Dns-AAs. Chiral discrimination ability of PMMABCD was demonstrated by the separation of an artificial mixture of 8 Dns-AA pairs. Copyright © 2014 Elsevier B.V. All rights reserved.

Fluid intensifier having a double acting power chamber with interconnected signal rods

DOEpatents

Whitehead, John C.

2001-01-01

A fluid driven reciprocating apparatus having a double acting power chamber with signal rods serving as high pressure pistons, or to transmit mechanical power. The signal rods are connected to a double acting piston in the power chamber thereby eliminating the need for pilot valves, with the piston being controlled by a pair of intake-exhaust valves. The signal rod includes two spaced seals along its length with a vented space therebetween so that the driving fluid and driven fluid can't mix, and performs a switching function to eliminate separate pilot valves. The intake-exhaust valves can be integrated into a single housing with the power chamber, or these valves can be built into the cylinder head only of the power chamber, or they can be separate from the power chamber.

A Polarimetric Approach for Constraining the Dynamic Foreground Spectrum for Cosmological Global 21 cm Measurements

NASA Astrophysics Data System (ADS)

Nhan, Bang D.; Bradley, Richard F.; Burns, Jack O.

2017-02-01

The cosmological global (sky-averaged) 21 cm signal is a powerful tool to probe the evolution of the intergalactic medium in high-redshift universe (z≤slant 6). One of the biggest observational challenges is to remove the foreground spectrum which is at least four orders of magnitude brighter than the cosmological 21 cm emission. Conventional global 21 cm experiments rely on the spectral smoothness of the foreground synchrotron emission to separate it from the unique 21 cm spectral structures in a single total-power spectrum. However, frequency-dependent instrumental and observational effects are known to corrupt such smoothness and complicate the foreground subtraction. We introduce a polarimetric approach to measure the projection-induced polarization of the anisotropic foreground onto a stationary dual-polarized antenna. Due to Earth rotation, when pointing the antenna at a celestial pole, the revolving foreground will modulate this polarization with a unique frequency-dependent sinusoidal signature as a function of time. In our simulations, by harmonic decomposing this dynamic polarization, our technique produces two separate spectra in parallel from the same observation: (I) a total sky power consisting both the foreground and the 21 cm background and (II) a model-independent measurement of the foreground spectrum at a harmonic consistent to twice the sky rotation rate. In the absence of any instrumental effects, by scaling and subtracting the latter from the former, we recover the injected global 21 cm model within the assumed uncertainty. We further discuss several limiting factors and potential remedies for future implementation.

Selecting a separable parametric spatiotemporal covariance structure for longitudinal imaging data.

PubMed

George, Brandon; Aban, Inmaculada

2015-01-15

Longitudinal imaging studies allow great insight into how the structure and function of a subject's internal anatomy changes over time. Unfortunately, the analysis of longitudinal imaging data is complicated by inherent spatial and temporal correlation: the temporal from the repeated measures and the spatial from the outcomes of interest being observed at multiple points in a patient's body. We propose the use of a linear model with a separable parametric spatiotemporal error structure for the analysis of repeated imaging data. The model makes use of spatial (exponential, spherical, and Matérn) and temporal (compound symmetric, autoregressive-1, Toeplitz, and unstructured) parametric correlation functions. A simulation study, inspired by a longitudinal cardiac imaging study on mitral regurgitation patients, compared different information criteria for selecting a particular separable parametric spatiotemporal correlation structure as well as the effects on types I and II error rates for inference on fixed effects when the specified model is incorrect. Information criteria were found to be highly accurate at choosing between separable parametric spatiotemporal correlation structures. Misspecification of the covariance structure was found to have the ability to inflate the type I error or have an overly conservative test size, which corresponded to decreased power. An example with clinical data is given illustrating how the covariance structure procedure can be performed in practice, as well as how covariance structure choice can change inferences about fixed effects. Copyright © 2014 John Wiley & Sons, Ltd.

Engineering Models Ease and Speed Prototyping

NASA Technical Reports Server (NTRS)

2008-01-01

NASA astronauts plan to return to the Moon as early as 2015 and establish a lunar base, from which 6-month flights to Mars would be launched by 2030. Essential to this plan is the Ares launch vehicle, NASA s next-generation spacecraft that will, in various iterations, be responsible for transporting all equipment and personnel to the Moon, Mars, and beyond for the foreseeable future. The Ares launch vehicle is powered by the J-2X propulsion system, with what will be the world s largest rocket nozzles. One of the conditions that engineers carefully consider in designing rocket nozzles particularly large ones is called separation phenomenon, which occurs when outside ambient air is sucked into the nozzle rim by the relatively low pressures of rapidly expanding exhaust gasses. This separation of exhaust gasses from the side-wall imparts large asymmetric transverse loads on the nozzle, deforming the shape and thus perturbing exhaust flow to cause even greater separation. The resulting interaction can potentially crack the nozzle or break actuator arms that control thrust direction. Side-wall loads are extremely difficult to measure directly, and, until now, techniques were not available for accurately predicting the magnitude and frequency of the loads. NASA researchers studied separation phenomenon in scale-model rocket nozzles, seeking to use measured vibration on these nozzle replicas to calculate the unknown force causing the vibrations. Key to this approach was the creation of a computer model accurately representing the nozzle as well as the test cell.

A proposed metabolic strategy for monitoring disease progression in Alzheimer's disease.

PubMed

Greenberg, Nicola; Grassano, Antonio; Thambisetty, Madhav; Lovestone, Simon; Legido-Quigley, Cristina

2009-04-01

A specific, sensitive and essentially non-invasive assay to diagnose and monitor Alzheimer's disease (AD) would be valuable to both clinicians and medical researchers. The aim of this study was to perform a metabonomic statistical analysis on plasma fingerprints. Objectives were to investigate novel biomarkers indicative of AD, to consider the role of bile acids as AD biomarkers and to consider whether mild cognitive impairment (MCI) is a separate disease from AD. Samples were analysed by ultraperformance liquid chromatography-MS and resulting data sets were interpreted using soft-independent modelling of class analogy statistical analysis methods. PCA models did not show any grouping of subjects by disease state. Partial least-squares discriminant analysis (PLS-DS) models yielded class separation for AD. However, as with earlier studies, model validation revealed a predictive power of Q(2)<0.5 and indicating their unsuitability for predicting disease state. Three bile acids were extracted from the data and quantified, up-regulation was observed for MCI and AD patients. PLS-DA did not support MCI being considered as a separate disease from AD with MCI patient metabolic profiles being significantly closer to AD patients than controls. This study suggested that further investigation into the lipid fraction of the metabolome may yield useful biomarkers for AD and metabolomic profiles could be used to predict disease state in a clinical setting.

Engine-integrated solid oxide fuel cells for efficient electrical power generation on aircraft

NASA Astrophysics Data System (ADS)

Waters, Daniel F.; Cadou, Christopher P.

2015-06-01

This work investigates the use of engine-integrated catalytic partial oxidation (CPOx) reactors and solid oxide fuel cells (SOFCs) to reduce fuel burn in vehicles with large electrical loads like sensor-laden unmanned air vehicles. Thermodynamic models of SOFCs, CPOx reactors, and three gas turbine (GT) engine types (turbojet, combined exhaust turbofan, separate exhaust turbofan) are developed and checked against relevant data and source material. Fuel efficiency is increased by 4% and 8% in the 50 kW and 90 kW separate exhaust turbofan systems respectively at only modest cost in specific power (8% and 13% reductions respectively). Similar results are achieved in other engine types. An additional benefit of hybridization is the ability to provide more electric power (factors of 3 or more in some cases) than generator-based systems before encountering turbine inlet temperature limits. A sensitivity analysis shows that the most important parameters affecting the system's performance are operating voltage, percent fuel oxidation, and SOFC assembly air flows. Taken together, this study shows that it is possible to create a GT-SOFC hybrid where the GT mitigates balance of plant losses and the SOFC raises overall system efficiency. The result is a synergistic system with better overall performance than stand-alone components.

Assessment of Energy Production Potential from Ocean Currents along the United States Coastline

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

Haas, Kevin

Increasing energy consumption and depleting reserves of fossil fuels have resulted in growing interest in alternative renewable energy from the ocean. Ocean currents are an alternative source of clean energy due to their inherent reliability, persistence and sustainability. General ocean circulations exist in the form of large rotating ocean gyres, and feature extremely rapid current flow in the western boundaries due to the Coriolis Effect. The Gulf Stream system is formed by the western boundary current of the North Atlantic Ocean that flows along the east coastline of the United States, and therefore is of particular interest as a potentialmore » energy resource for the United States. This project created a national database of ocean current energy resources to help advance awareness and market penetration in ocean current energy resource assessment. The database, consisting of joint velocity magnitude and direction probability histograms, was created from data created by seven years of numerical model simulations. The accuracy of the database was evaluated by ORNL?s independent validation effort documented in a separate report. Estimates of the total theoretical power resource contained in the ocean currents were calculated utilizing two separate approaches. Firstly, the theoretical energy balance in the Gulf Stream system was examined using the two-dimensional ocean circulation equations based on the assumptions of the Stommel model for subtropical gyres with the quasi-geostrophic balance between pressure gradient, Coriolis force, wind stress and friction driving the circulation. Parameters including water depth, natural dissipation rate and wind stress are calibrated in the model so that the model can reproduce reasonable flow properties including volume flux and energy flux. To represent flow dissipation due to turbines additional turbine drag coefficient is formulated and included in the model. Secondly, to determine the reasonableness of the total power estimates from the Stommel model and to help determine the size and capacity of arrays necessary to extract the maximum theoretical power, further estimates of the available power based on the distribution of the kinetic power density in the undisturbed flow was completed. This used estimates of the device spacing and scaling to sum up the total power that the devices would produce. The analysis has shown that considering extraction over a region comprised of the Florida Current portion of the Gulf Stream system, the average power dissipated ranges between 4-6 GW with a mean around 5.1 GW. This corresponds to an average of approximately 45 TWh/yr. However, if the extraction area comprises the entire portion of the Gulf Stream within 200 miles of the US coastline from Florida to North Carolina, the average power dissipated becomes 18.6 GW or 163 TWh/yr. A web based GIS interface, http://www.oceancurrentpower.gatech.edu/, was developed for dissemination of the data. The website includes GIS layers of monthly and yearly mean ocean current velocity and power density for ocean currents along the entire coastline of the United States, as well as joint and marginal probability histograms for current velocities at a horizontal resolution of 4-7 km with 10-25 bins over depth. Various tools are provided for viewing, identifying, filtering and downloading the data.« less

Public health law and disaster medicine: understanding the legal environment.

PubMed

Gionis, Thomas A; Wecht, Cyril; Marshall, Lewis W

2007-01-01

Disaster medicine specialists, policy makers, and the public often feel frustrated when they encounter the complex legal framework that surrounds public health emergencies and disasters. Such a framework is particularly difficult to understand when one considers that the federal government has no express powers over public health or disaster management. In fact, under the US Constitution, the states, rather than the federal government, possess public health governance. Although public health sovereignty formally resides within the states, and notwithstanding the federal government's lack of express constitutional powers over public health crises and disaster management, the federal government has gradually taken on a greater leadership role in managing public health emergencies. In order to clarify the state and federal responsibilities surrounding public health emergencies and disasters, this article explores necessary and pertinent legal topics. These topics include public health duties, public health disasters, state sovereignty, governmental coercion, de facto constitutional empowerment, separation of powers, limited powers, federalism, state police powers, general and federal declarations of emergencies, the Model State Emergency Health Powers Act (MSEHPA), and public health and national security.

Robust Wireless Power Transmission to mm-Sized Free-Floating Distributed Implants.

PubMed

Mirbozorgi, S Abdollah; Yeon, Pyungwoo; Ghovanloo, Maysam

2017-06-01

This paper presents an inductive link for wireless power transmission (WPT) to mm-sized free-floating implants (FFIs) distributed in a large three-dimensional space in the neural tissue that is insensitive to the exact location of the receiver (Rx). The proposed structure utilizes a high-Q resonator on the target wirelessly powered plane that encompasses randomly positioned multiple FFIs, all powered by a large external transmitter (Tx). Based on resonant WPT fundamentals, we have devised a detailed method for optimization of the FFIs and explored design strategies and safety concerns, such as coil segmentation and specific absorption rate limits using realistic finite element simulation models in HFSS including head tissue layers, respectively. We have built several FFI prototypes to conduct accurate measurements and to characterize the performance of the proposed WPT method. Measurement results on 1-mm receivers operating at 60 MHz show power transfer efficiency and power delivered to the load at 2.4% and 1.3 mW, respectively, within 14-18 mm of Tx-Rx separation and 7 cm 2 of brain surface.

Development of a thermodynamic model for a cold cycle 3He-4He dilution refrigerator

NASA Astrophysics Data System (ADS)

Mueller, B. W.; Miller, F. K.

2016-10-01

A thermodynamic model of a 3He-4He cold cycle dilution refrigerator with no actively-driven mechanical components is developed and investigated. The refrigerator employs a reversible superfluid magnetic pump, passive check valves, a phase separation chamber, and a series of recuperative heat exchangers to continuously circulate 3He-4He and maintain a 3He concentration gradient across the mixing chamber. The model predicts cooling power and mixing chamber temperature for a range of design and operating parameters, allowing an evaluation of feasibility for potential 3He-4He cold cycle dilution refrigerator prototype designs. Model simulations for a prototype refrigerator design are presented.

Energy dissipation in polymer-polymer adhesion contacts

NASA Astrophysics Data System (ADS)

Garif, Yev Skip

This study focuses on self-adhesion in elastomers as a way of approaching a broader polymer adhesion problem. The model systems studied are cross-linked acrylic pressure-sensitive adhesives (PSA-LNs) synthesized to attain four surface types: neutral, acidic, basic, and polar. As the study progressed, it distinguished itself as the first of its kind to consistently report the effect of temperature on measurable intrinsic parameters of polymer adhesion. The main goal of the study was to understand why the magnitude of the practical adhesion energies of the four PSA-LN systems tested varies disproportionately greater than their respective surface energies. To achieve this goal, continuous sweeps of adhesion energy as a function of rate of interfacial separation were performed using three different adhesion-probing techniques--- peel, micro-scratch, and normal contact. The answer was found in the sub-micron-per-second limit of separation rates. In approaching this limit, the power law behavior of adhesion gradually transitioned into a linear region of markedly weaker sensitivity to rate. Referred to as the "intrinsic window", this linear region was characterized by three parameters: (1) the intrinsic adhesion energy at zero rate of separation; (2) the intrinsic rate sensitivity equal to the proportionality constant of the linear fit; and (3) the critical separation rate in the middle of the transition to the power law. All three were found to be thermally activated. Activation energies suggested that interfacial processes are attributed mainly to dispersive and electrostatic molecular interactions such as hydrogen bonding or van der Waals attraction. Comparative analysis of the intrinsic window of the four PSA-LNs tested showed that an increase in the intrinsic adhesion energy associated with higher surface energy is inherently coupled with an increase in the intrinsic rate sensitivity and reduction in the critical separation rate. When combined, the three parameters reshape the intrinsic window such that the entire power-law portion of the adhesion response is shifted to a level that appears disproportionately high based on the false assumption that there is only one intrinsic parameter contributing to the shift. Thus, the goal of explaining this disproportionality was achieved.

Velocity model of the shallow lunar crust

NASA Technical Reports Server (NTRS)

Gangi, A. F.

1980-01-01

The travel times of the seismic waves obtained for the Apollo-14 and -16 active seismic experiments and the Apollo-16 grenade launches are shown to be consistent with a powder-layer model of the shallow lunar crust. The velocity variation with depth determined from these data is: V(z) = approximately 110 z to the 1/6 power m/sec for z less than 10 meters and V(z) is nearly = to 250 m/sec for z greater than 10 meters. The velocity values found for the 10 meter depth are similar to those found by Kovach, et al. (1972). The z to the 1/6 power depth dependence for the velocity of the topmost layer is that predicted on the basis of a powder layer (Gangi, 1972). The Amplitude variation of the direct waves as a function of source-to-receiver separation, x, is A(x) = A(o)x to the -n power exp(-ax) where 1.5 n 2.2 and a is nearly = to 0.047 neper/m. Velocity-spectra analyses of the direct, surface-reflected, bottom-reflected and refracted waves give results that are consistent with the velocity model inferred from the traveltime data.

Vertical phase separation in bulk heterojunction solar cells formed by in situ polymerization of fulleride

PubMed Central

Zhang, Lipei; Xing, Xing; Zheng, Lingling; Chen, Zhijian; Xiao, Lixin; Qu, Bo; Gong, Qihuang

2014-01-01

Vertical phase separation of the donor and the acceptor in organic bulk heterojunction solar cells is crucial to improve the exciton dissociation and charge transport efficiencies. This is because whilst the exciton diffusion length is limited, the organic film must be thick enough to absorb sufficient light. However, it is still a challenge to control the phase separation of a binary blend in a bulk heterojunction device architecture. Here we report the realization of vertical phase separation induced by in situ photo-polymerization of the acrylate-based fulleride. The power conversion efficiency of the devices with vertical phase separation increased by 20%. By optimising the device architecture, the power conversion efficiency of the single junction device reached 8.47%. We believe that in situ photo-polymerization of acrylate-based fulleride is a universal and controllable way to realise vertical phase separation in organic blends. PMID:24861168

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

Zhang, Xing; Ibrahim, Yehia M.; Chen, Tsung-Chi

We report the first evaluation of a platform coupling a high speed field asymmetric ion mobility spectrometry microchip (µFAIMS) with drift tube ion mobility and mass spectrometry (IMS-MS). The µFAIMS/IMS-MS platform was used to analyze biological samples and simultaneously acquire multidimensional information of detected features from the measured FAIMS compensation fields and IMS drift times, while also obtaining accurate ion masses. These separations thereby increase the overall separation power, resulting increased information content, and provide more complete characterization of more complex samples. The separation conditions were optimized for sensitivity and resolving power by the selection of gas compositions and pressuresmore » in the FAIMS and IMS separation stages. The resulting performance provided three dimensional separations, benefitting both broad complex mixture studies and targeted analyses by e.g. improving isomeric separations and allowing detection of species obscured by “chemical noise” and other interfering peaks.« less

A simplified and powerful image processing methods to separate Thai jasmine rice and sticky rice varieties

NASA Astrophysics Data System (ADS)

Khondok, Piyoros; Sakulkalavek, Aparporn; Suwansukho, Kajpanya

2018-03-01

A simplified and powerful image processing procedures to separate the paddy of KHAW DOK MALI 105 or Thai jasmine rice and the paddy of sticky rice RD6 varieties were proposed. The procedures consist of image thresholding, image chain coding and curve fitting using polynomial function. From the fitting, three parameters of each variety, perimeters, area, and eccentricity, were calculated. Finally, the overall parameters were determined by using principal component analysis. The result shown that these procedures can be significantly separate both varieties.

Out of the Blue and Into the Black: Creation of the United States Space Force.

DTIC Science & Technology

1998-03-01

organizational diagnosis as a theorem for strategic change. An autopsy of related research and literature was conducted in order to establish justification for a separate service to advance space power for the nation. The first dimension examined is the medium of space. Defining the medium, along with such areas as airpower and space power establishes a factual foundation from which to launch the idea of a separate service. Reasoning for and against a separate service is presented, including application of the Organizational Diagnosis to the Air

Real-Time Simulation of Ares I Launch Vehicle

NASA Technical Reports Server (NTRS)

Tobbe, Patrick; Matras, Alex; Wilson, Heath; Alday, Nathan; Walker, David; Betts, Kevin; Hughes, Ryan; Turbe, Michael

2009-01-01

The Ares Real-Time Environment for Modeling, Integration, and Simulation (ARTEMIS) has been developed for use by the Ares I launch vehicle System Integration Laboratory (SIL) at the Marshall Space Flight Center (MSFC). The primary purpose of the Ares SIL is to test the vehicle avionics hardware and software in a hardware-in-the-loop (HWIL) environment to certify that the integrated system is prepared for flight. ARTEMIS has been designed to be the real-time software backbone to stimulate all required Ares components through high-fidelity simulation. ARTEMIS has been designed to take full advantage of the advances in underlying computational power now available to support HWIL testing. A modular real-time design relying on a fully distributed computing architecture has been achieved. Two fundamental requirements drove ARTEMIS to pursue the use of high-fidelity simulation models in a real-time environment. First, ARTEMIS must be used to test a man-rated integrated avionics hardware and software system, thus requiring a wide variety of nominal and off-nominal simulation capabilities to certify system robustness. The second driving requirement - derived from a nationwide review of current state-of-the-art HWIL facilities - was that preserving digital model fidelity significantly reduced overall vehicle lifecycle cost by reducing testing time for certification runs and increasing flight tempo through an expanded operational envelope. These two driving requirements necessitated the use of high-fidelity models throughout the ARTEMIS simulation. The nature of the Ares mission profile imposed a variety of additional requirements on the ARTEMIS simulation. The Ares I vehicle is composed of multiple elements, including the First Stage Solid Rocket Booster (SRB), the Upper Stage powered by the J- 2X engine, the Orion Crew Exploration Vehicle (CEV) which houses the crew, the Launch Abort System (LAS), and various secondary elements that separate from the vehicle. At launch, the integrated vehicle stack is composed of these stages, and throughout the mission, various elements separate from the integrated stack and tumble back towards the earth. ARTEMIS must be capable of simulating the integrated stack through the flight as well as propagating each individual element after separation. In addition, abort sequences can lead to other unique configurations of the integrated stack as the timing and sequence of the stage separations are altered.

Mathematical Modeling of High-Temperature Constitutive Equations and Hot Processing Maps for As-Cast SA508-3 Steel

NASA Astrophysics Data System (ADS)

Sui, Dashan; Wang, Tao; Zhu, Lingling; Gao, Liang; Cui, Zhenshan

2016-11-01

The hot deformation behavior and hot workability characteristics of as-cast SA508-3 steel were studied by modeling the constitutive equations and developing hot processing maps. The isothermal compression experiments were carried out at temperatures of 950°C, 1050°C, 1150°C, and 1250°C and strain rates of 0.001 s-1, 0.01 s-1, 0.1 s-1, and 1 s-1 respectively. The two-stage flow stress models were established through the classical theories on work hardening and softening, and the solution of activation energy for hot deformation was 355.0 kJ mol-1 K-1. Based on the dynamic material model, the power dissipation and instability maps were developed separately at strains of 0.2, 0.4, 0.6 and 0.8. The power dissipation rate increases with both the increase of temperature and the decrease of strain rate, and the instable region mainly appears on the conditions of low temperature and high strain rate. The optimal hot working parameters for as-cast SA508-3 steel are 1050-1200°C/0.001-0.1 s-1, with about 25-40% peak efficiency of power dissipation.

Venus cloud bobber mission: A long term survey of the Venusian surface

NASA Technical Reports Server (NTRS)

Wai, James; Derengowski, Cheryl; Lautzenhiser, Russ; Emerson, Matt; Choi, Yongho

1994-01-01

We have examined the Venus Balloon concept in order to further develop the ideas and concepts behind it, and to creatively apply them to the design of the major Venus Balloon components. This report presents our models of the vertical path taken by the Venus Balloon and the entry into Venusian atmosphere. It also details our designs of the balloon, gondola, heat exchanger, power generator, and entry module. A vehicle is designed for a ballistic entry into the Venusian atmosphere, and an atmospheric model is created. The model is then used to set conditions. The shape and material of the vehicle are optimized, and the dimensions of the vehicle are then determined. Equipment is chosen and detailed that will be needed to collect and transmit information and control the mission. A gondola is designed that will enable this sensitive electronic equipment to survive in an atmosphere of very high temperature and pressure. This shape and the material of the shell are optimized, and the size is minimized. Insulation and supporting structures are designed to protect the payload equipment and to minimize mass. A method of cooling the gondola at upper altitudes was established. Power needs of the gondola equipment are determined. Power generation options are discussed and two separate thermoelectric generation models are outlined.

Perturbative Power Counting, Lowest-Index Operators and Their Renormalization in Standard Model Effective Field Theory

NASA Astrophysics Data System (ADS)

Liao, Yi; Ma, Xiao-Dong

2018-03-01

We study two aspects of higher dimensional operators in standard model effective field theory. We first introduce a perturbative power counting rule for the entries in the anomalous dimension matrix of operators with equal mass dimension. The power counting is determined by the number of loops and the difference of the indices of the two operators involved, which in turn is defined by assuming that all terms in the standard model Lagrangian have an equal perturbative power. Then we show that the operators with the lowest index are unique at each mass dimension d, i.e., (H † H) d/2 for even d ≥ 4, and (LT∈ H)C(LT∈ H) T (H † H)(d-5)/2 for odd d ≥ 5. Here H, L are the Higgs and lepton doublet, and ∈, C the antisymmetric matrix of rank two and the charge conjugation matrix, respectively. The renormalization group running of these operators can be studied separately from other operators of equal mass dimension at the leading order in power counting. We compute their anomalous dimensions at one loop for general d and find that they are enhanced quadratically in d due to combinatorics. We also make connections with classification of operators in terms of their holomorphic and anti-holomorphic weights. Supported by the National Natural Science Foundation of China under Grant Nos. 11025525, 11575089, and by the CAS Center for Excellence in Particle Physics (CCEPP)

Harnessing electrical forces for separation. Capillary zone electrophoresis, isoelectric focusing, field-flow fractionation, split-flow thin-cell continuous-separation and other techniques.

PubMed

Giddings, J C

1989-10-20

A simple analysis, first presented twenty years ago, showed that the effectiveness of a field-driven separation like electrophoresis, as expressed by the maximum number of theoretical plates (N), is given by the dimensionless ratio of two energies N = -delta mu ext/2RT in which -delta mu ext is the electrical potential energy drop of a charged species and RT is the thermal energy (R is the gas constant and T is the absolute temperature). Quantity -delta mu ext is the product of the force F acting on the species and the path length X of separation. The exceptional power of electrophoresis, for which often N approximately 10(6), can be traced directly to the enormous magnitude of the electrical force F. This paper explores the fundamentals underlying several different means for utilizing these powerful electrical forces for separation, including capillary zone electrophoresis, gel electrophoresis, isoelectric focusing, electrical field-flow fractionation and split-flow thin continuous separation cells. Remarkably, the above equation and its relatives are found to describe the approximate performance of all these diverse electrically driven systems. Factors affecting both the resolving power and separation speed of the systems are addressed; from these considerations some broad optimization criteria emerge. The capabilities of the different methods are compared using numerical examples.

A Dynamic Evaluation Of A Model And An Estimate Of The Air Quality And Regional Climate Impacts Of Enhanced Solar Power Generation

NASA Astrophysics Data System (ADS)

Millstein, D.; Brown, N. J.; Zhai, P.; Menon, S.

2012-12-01

We use the WRF/Chem model (Weather Research and Forecasting model with chemistry) and pollutant emissions based on the EPA National Emission Inventories from 2005 and 2008 to model regional climate and air quality over the continental United States. Additionally, 2030 emission scenarios are developed to investigate the effects of future enhancements to solar power generation. Modeling covered 6 summer and 6 winter weeks each year. We model feedback between aerosols and meteorology and thus capture direct and indirect aerosol effects. The grid resolution is 25 km and includes no nesting. Between 2005 and 2008 significant emission reductions were reported in the National Emission Inventory. The 2008 weekday emissions over the continental U.S. of SO2 and NO were reduced from 2005 values by 28% and 16%, respectively. Emission reductions of this magnitude are similar in scale to the potential emission reductions from various energy policy initiatives. By evaluating modeled and observed air quality changes from 2005 to 2008, we analyze how well the model represents the effects of historical emission changes. We also gain insight into how well the model might predict the effects of future emission changes. In addition to direct comparisons of model outputs to ground and satellite observations, we compare observed differences between 2005 and 2008 to corresponding modeled differences. Modeling was extended to future scenarios (2030) to simulate air quality and regional climate effects of large-scale adoption of solar power. The 2030-year was selected to allow time for development of solar generation infrastructure. The 2030 emission scenario was scaled, with separate factors for different economic sectors, from the 2008 National Emissions Inventory. The changes to emissions caused by the introduction of large-scale solar power (here assumed to be 10% of total energy generation) are based on results from a parallel project that used an electricity grid model applied over multiple regions across the country. The regional climate and air quality effects of future large-scale solar power adoption are analyzed in the context of uncertainty quantified by the dynamic evaluation of the historical (2005 and 2008) WRF/Chem simulations.

Desegregation of Public Schools. Testimony before the Subcommittee on Separation of Powers, Committee on the Judiciary, United States Senate.

ERIC Educational Resources Information Center

Reynolds, William Bradford

This testimony was delivered by William Bradford Reynolds, the Assistant Attorney General of the Civil Rights Division, before the Subcommttee on Separation of Powers, Committee on the Judiciary of the United States Senate. Reynold states that compulsory busing of students is not an acceptable remedy to achieve racial balance. He emphasizes the…

Constitutional Principles and E-Government: An Opinion about Possible Effects of Federalism and the Separation of Powers on E-Government Policies.

ERIC Educational Resources Information Center

Jaeger, Paul T.

2002-01-01

Examines how Constitutional principles, specifically the doctrines of Federalism and the separation of powers, relate to e-government policies and practices. Suggests that the move toward e-government, with emphasis on the simplification of access to government information and services, must be considered with regard to Federalism and separation…

Constitutional Issues: Separation of Powers. Teaching with Documents.

ERIC Educational Resources Information Center

National Archives and Records Administration, Washington, DC.

The United States subscribes to the original premise of the framers of the Constitution that the way to safeguard against tyranny is to separate the powers of government among three branches so that each branch checks the other two. At no time in the 20th century was the devotion to that principle more vigorously evoked than in 1937, when…

The Availability of Judicial Review Regarding Military Base Closures and Realignments

DTIC Science & Technology

2005-06-30

held that the President is not subject to the APA, due to separation of powers principles.37 Base Closure Act Claims The Dalton Court distinguished...that the 1988 Base Closure Act violated the non-delegation doctrine and the separation of powers doctrine.53 However, the Base Closure Act has not yet been held unconstitutional by any federal appellate courts.

Power Systems and Energy Storage Modeling for Directed Energy Weapons

DTIC Science & Technology

2014-06-01

neodymium or ytterbium doped yttrium aluminum garnet (YAG) crystal.6 The Maritime Laser Demonstration (MLD) features several 15 kW slab lasers combined...The laser substrate is similar to a fiber optic cable that is doped with a rare earth element (typically neodymium or ytterbium); many fibers can be...but with different elements. A typical construction consists of a sheet of Lithium- cobalt -oxide and a sheet of carbon separated by an insulator

Cryptography from noisy storage.

PubMed

Wehner, Stephanie; Schaffner, Christian; Terhal, Barbara M

2008-06-06

We show how to implement cryptographic primitives based on the realistic assumption that quantum storage of qubits is noisy. We thereby consider individual-storage attacks; i.e., the dishonest party attempts to store each incoming qubit separately. Our model is similar to the model of bounded-quantum storage; however, we consider an explicit noise model inspired by present-day technology. To illustrate the power of this new model, we show that a protocol for oblivious transfer is secure for any amount of quantum-storage noise, as long as honest players can perform perfect quantum operations. Our model also allows us to show the security of protocols that cope with noise in the operations of the honest players and achieve more advanced tasks such as secure identification.

Computational studies of the effects of active and passive circulation enhancement concepts on wind turbine performance

NASA Astrophysics Data System (ADS)

Tongchitpakdee, Chanin

With the advantage of modern high speed computers, there has been an increased interest in the use of first-principles based computational approaches for the aerodynamic modeling of horizontal axis wind turbine (HAWT). Since these approaches are based on the laws of conservation (mass, momentum, and energy), they can capture much of the physics in great detail. The ability to accurately predict the airloads and power output can greatly aid the designers in tailoring the aerodynamic and aeroelastic features of the configuration. First-principles based analyses are also valuable for developing active means (e.g., circulation control), and passive means (e.g., Gurney flaps) of reducing unsteady blade loads, mitigating stall, and for efficient capture of wind energy leading to more electrical power generation. In this present study, the aerodynamic performance of a wind turbine rotor equipped with circulation enhancement technology (trailing edge blowing or Gurney flaps) is investigated using a three-dimensional unsteady viscous flow analysis. The National Renewable Energy Laboratory (NREL) Phase VI horizontal axis wind turbine is chosen as the baseline configuration. Prior to its use in exploring these concepts, the flow solver is validated with the experimental data for the baseline case under yawed flow conditions. Results presented include radial distribution of normal and tangential forces, shaft torque, root flap moment, surface pressure distributions at selected radial locations, and power output. Results show that good agreement has been for a range of wind speeds and yaw angles, where the flow is attached. At high wind speeds, however, where the flow is fully separated, it was found that the fundamental assumptions behind this present methodology breaks down for the baseline turbulence model (Spalart-Allmaras model), giving less accurate results. With the implementation of advanced turbulence model, Spalart-Allmaras Detached Eddy Simulation (SA-DES), the accuracy of the results at high wind speeds are improved. Results of circulation enhancement concepts show that, at low wind speed (attached flow) conditions, a Coanda jet at the trailing edge of the rotor blade is effective at increasing circulation resulting in an increase of lift and the chordwise thrust force. This leads to an increased amount of net power generation compared to the baseline configuration for moderate blowing coefficients. The effects of jet slot height and pulsed jet are also investigated in this study. A passive Gurney flap was found to increase the bound circulation and produce increased power in a manner similar to the Coanda jet. At high wind speed where the flow is separated, both the Coanda jet and Gurney flap become ineffective. Results of leading edge blowing indicate that a leading edge blowing jet is found to be beneficial in increasing power generation at high wind speeds. The effect of Gurney flap angle is also studied. Gurney flap angle has significant influence in power generation. Higher power output is obtained at higher flap angles.

Radiation effects in concrete for nuclear power plants, Part II: Perspective from micromechanical modeling

DOE PAGES

Le Pape, Yann; Field, Kevin G.; Remec, Igor

2014-11-15

The need to understand and characterize the effects of neutron irradiation on concrete has become urgent because of the possible extension of service life of many nuclear power generating stations. Current knowledge is primarily based on a collection of data obtained in test reactors. These results are inherently difficult to interpret because materials and testing conditions are inconsistent. A micromechanical approach based on the Hashin composite sphere model is presented to derive a first-order separation of the effects of radiation on cement paste and aggregate, and, also, on their interaction. Although the scarcity of available data limits the validation ofmore » the model, it appears that, without negating a possible gamma-ray induced effect, the neutron-induced damage and swelling of aggregate plays a predominant role on the overall concrete expansion and the damage of the cement paste. Finally, the radiation-induced volumetric expansion (RIVE) effects can also be aided by temperature elevation and shrinkage in the cement paste.« less

Emergent traffic jams

NASA Astrophysics Data System (ADS)

Nagel, Kai; Paczuski, Maya

1995-04-01

We study a single-lane traffic model that is based on human driving behavior. The outflow from a traffic jam self-organizes to a critical state of maximum throughput. Small perturbations of the outflow far downstream create emergent traffic jams with a power law distribution P(t)~t-3/2 of lifetimes t. On varying the vehicle density in a closed system, this critical state separates lamellar and jammed regimes and exhibits 1/f noise in the power spectrum. Using random walk arguments, in conjunction with a cascade equation, we develop a phenomenological theory that predicts the critical exponents for this transition and explains the self-organizing behavior. These predictions are consistent with all of our numerical results.

On the characteristics of emulsion chamber family events produced in low heights

NASA Technical Reports Server (NTRS)

Jing, G.; Jing, C.; Zhu, Q.; Ding, L.

1985-01-01

The uncertainty of the primary cosmic ray composition at 10 to the 14th power -10 to the 16th power eV is well known to make the study of the nuclear interaction mechanism more difficult. Experimentally considering, if one can identify effectively the family events which are produced in low heights, then an event sample induced by primary protons might be able to be separated. It is undoubtedly very meaningful. In this paper an attempt is made to simulate the family events under the condition of mountain emulsion chamber experiments with a reasonable model. The aim is to search for the dependence of some experimentally observable quantities to the interaction height.

Two-Pole Caustic Model for High-Energy Lightcurves of Pulsars

NASA Technical Reports Server (NTRS)

Dyks, J.; Rudak, B.

2003-01-01

We present a new model of high-energy lightcurves from rotation powered pulsars. The key ingredient of the model is the gap region (i.e. the region where particle acceleration is taking place and high-energy photons originate) which satisfies the following assumptions: i) the gap region extends from each polar cap to the light cylinder; ii) the gap is thin and confined to the surface of last open magnetic-field lines; iii) photon emissivity is uniform within the gap region. The model lightcurves are dominated by strong peaks (either double or single) of caustic origin. Unlike in other pulsar models with caustic effects, the double peaks arise due to crossing two caustics, each of which is associated with a different magnetic pole. The generic features of the lightcurves are consistent with the observed characteristics of pulsar lightcurves: 1) the most natural (in terms of probability) shape consists of two peaks (separated by 0.4 to 0.5 in phase for large viewing angles); 2) the peaks possess well developed wings; 3) there is a bridge (inter-peak) emission component; 4) there is a non-vanishing off-pulse emission level; 5) the radio pulse occurs before the leading high-energy peak. The model is well suited for four gamma-ray pulsars - Crab, Vela, Geminga and B1951+32 - with double-peak lightcurves exhibiting the peak separation of 0.4 to 0.5 in phase. Hereby, we apply the model to the Vela pulsar. Moreover, we indicate the limitation of the model in accurate reproducing of the lightcurves with single pulses and narrowly separated (about 0.2 in phase) pulse peaks. We also discuss the optical polarization properties for the Crab pulsar in the context of the two-pole caustic model.

Multiplex electric discharge gas laser system

NASA Technical Reports Server (NTRS)

Laudenslager, James B. (Inventor); Pacala, Thomas J. (Inventor)

1987-01-01

A multiple pulse electric discharge gas laser system is described in which a plurality of pulsed electric discharge gas lasers are supported in a common housing. Each laser is supplied with excitation pulses from a separate power supply. A controller, which may be a microprocessor, is connected to each power supply for controlling the application of excitation pulses to each laser so that the lasers can be fired simultaneously or in any desired sequence. The output light beams from the individual lasers may be combined or utilized independently, depending on the desired application. The individual lasers may include multiple pairs of discharge electrodes with a separate power supply connected across each electrode pair so that multiple light output beams can be generated from a single laser tube and combined or utilized separately.

Optimization of the oxidant supply system for combined cycle MHD power plants

NASA Technical Reports Server (NTRS)

Juhasz, A. J.

1982-01-01

An in-depth study was conducted to determine what, if any, improvements could be made on the oxidant supply system for combined cycle MHD power plants which could be reflected in higher thermal efficiency and a reduction in the cost of electricity, COE. A systematic analysis of air separation process varitions which showed that the specific energy consumption could be minimized when the product stream oxygen concentration is about 70 mole percent was conducted. The use of advanced air compressors, having variable speed and guide vane position control, results in additional power savings. The study also led to the conceptual design of a new air separation process, sized for a 500 MW sub e MHD plant, referred to a internal compression is discussed. In addition to its lower overall energy consumption, potential capital cost savings were identified for air separation plants using this process when constructed in a single large air separation train rather than multiple parallel trains, typical of conventional practice.

Method for enhancing the resolving power of ion mobility separations over a limited mobility range

DOEpatents

Shvartsburg, Alexandre A; Tang, Keqi; Smith, Richard D

2014-09-23

A method for raising the resolving power, specificity, and peak capacity of conventional ion mobility spectrometry is disclosed. Ions are separated in a dynamic electric field comprising an oscillatory field wave and opposing static field, or at least two counter propagating waves with different parameters (amplitude, profile, frequency, or speed). As the functional dependencies of mean drift velocity on the ion mobility in a wave and static field or in unequal waves differ, only single species is equilibrated while others drift in either direction and are mobility-separated. An ion mobility spectrum over a limited range is then acquired by measuring ion drift times through a fixed distance inside the gas-filled enclosure. The resolving power in the vicinity of equilibrium mobility substantially exceeds that for known traveling-wave or drift-tube IMS separations, with spectra over wider ranges obtainable by stitching multiple segments. The approach also enables low-cutoff, high-cutoff, and bandpass ion mobility filters.

14 CFR 121.313 - Miscellaneous equipment.

Code of Federal Regulations, 2011 CFR

2011-01-01

... equivalent for each pilot station. (c) A power supply and distribution system that meets the requirements of... external power supply if any one power source or component of the power distribution system fails. The use... on separate engines. (d) A means for indicating the adequacy of the power being supplied to required...

14 CFR 121.313 - Miscellaneous equipment.

Code of Federal Regulations, 2013 CFR

2013-01-01

... equivalent for each pilot station. (c) A power supply and distribution system that meets the requirements of... external power supply if any one power source or component of the power distribution system fails. The use... on separate engines. (d) A means for indicating the adequacy of the power being supplied to required...

14 CFR 121.313 - Miscellaneous equipment.

Code of Federal Regulations, 2014 CFR

2014-01-01

... equivalent for each pilot station. (c) A power supply and distribution system that meets the requirements of... external power supply if any one power source or component of the power distribution system fails. The use... on separate engines. (d) A means for indicating the adequacy of the power being supplied to required...

The evolution of scaling laws in the sea ice floe size distribution

NASA Astrophysics Data System (ADS)

Horvat, Christopher; Tziperman, Eli

2017-09-01

The sub-gridscale floe size and thickness distribution (FSTD) is an emerging climate variable, playing a leading-order role in the coupling between sea ice, the ocean, and the atmosphere. The FSTD, however, is difficult to measure given the vast range of horizontal scales of individual floes, leading to the common use of power-law scaling to describe it. The evolution of a coupled mixed-layer-FSTD model of a typical marginal ice zone is explicitly simulated here, to develop a deeper understanding of how processes active at the floe scale may or may not lead to scaling laws in the floe size distribution. The time evolution of mean quantities obtained from the FSTD (sea ice concentration, mean thickness, volume) is complex even in simple scenarios, suggesting that these quantities, which affect climate feedbacks, should be carefully calculated in climate models. The emergence of FSTDs with multiple separate power-law regimes, as seen in observations, is found to be due to the combination of multiple scale-selective processes. Limitations in assuming a power-law FSTD are carefully analyzed, applying methods used in observations to FSTD model output. Two important sources of error are identified that may lead to model biases: one when observing an insufficiently small range of floe sizes, and one from the fact that floe-scale processes often do not produce power-law behavior. These two sources of error may easily lead to biases in mean quantities derived from the FSTD of greater than 100%, and therefore biases in modeled sea ice evolution.

Two Sides of the Same Coin: ERP and Wavelet Analyses of Visual Potentials Evoked and Induced by Task-Relevant Faces.

PubMed

Van der Lubbe, Rob H J; Szumska, Izabela; Fajkowska, Małgorzata

2016-01-01

New analysis techniques of the electroencephalogram (EEG) such as wavelet analysis open the possibility to address questions that may largely improve our understanding of the EEG and clarify its relation with related potentials (ER Ps). Three issues were addressed. 1) To what extent can early ERERP components be described as transient evoked oscillations in specific frequency bands? 2) Total EEG power (TP) after a stimulus consists of pre-stimulus baseline power (BP), evoked power (EP), and induced power (IP), but what are their respective contributions? 3) The Phase Reset model proposes that BP predicts EP, while the evoked model holds that BP is unrelated to EP; which model is the most valid one? EEG results on NoGo trials for 123 individuals that took part in an experiment with emotional facial expressions were examined by computing ERPs and by performing wavelet analyses on the raw EEG and on ER Ps. After performing several multiple regression analyses, we obtained the following answers. First, the P1, N1, and P2 components can by and large be described as transient oscillations in the α and θ bands. Secondly, it appears possible to estimate the separate contributions of EP, BP, and IP to TP, and importantly, the contribution of IP is mostly larger than that of EP. Finally, no strong support was obtained for either the Phase Reset or the Evoked model. Recent models are discussed that may better explain the relation between raw EEG and ERPs.

Two Sides of the Same Coin: ERP and Wavelet Analyses of Visual Potentials Evoked and Induced by Task-Relevant Faces

PubMed Central

Van der Lubbe, Rob H. J.; Szumska, Izabela; Fajkowska, Małgorzata

2016-01-01

New analysis techniques of the electroencephalogram (EEG) such as wavelet analysis open the possibility to address questions that may largely improve our understanding of the EEG and clarify its relation with related potentials (ER Ps). Three issues were addressed. 1) To what extent can early ERERP components be described as transient evoked oscillations in specific frequency bands? 2) Total EEG power (TP) after a stimulus consists of pre-stimulus baseline power (BP), evoked power (EP), and induced power (IP), but what are their respective contributions? 3) The Phase Reset model proposes that BP predicts EP, while the evoked model holds that BP is unrelated to EP; which model is the most valid one? EEG results on NoGo trials for 123 individuals that took part in an experiment with emotional facial expressions were examined by computing ERPs and by performing wavelet analyses on the raw EEG and on ER Ps. After performing several multiple regression analyses, we obtained the following answers. First, the P1, N1, and P2 components can by and large be described as transient oscillations in the α and θ bands. Secondly, it appears possible to estimate the separate contributions of EP, BP, and IP to TP, and importantly, the contribution of IP is mostly larger than that of EP. Finally, no strong support was obtained for either the Phase Reset or the Evoked model. Recent models are discussed that may better explain the relation between raw EEG and ERPs. PMID:28154612

Calibration power of the Braden scale in predicting pressure ulcer development.

PubMed

Chen, Hong-Lin; Cao, Ying-Juan; Wang, Jing; Huai, Bao-Sha

2016-11-02

Calibration is the degree of correspondence between the estimated probability produced by a model and the actual observed probability. The aim of this study was to investigate the calibration power of the Braden scale in predicting pressure ulcer development (PU). A retrospective analysis was performed among consecutive patients in 2013. The patients were separated into training a group and a validation group. The predicted incidence was calculated using a logistic regression model in the training group and the Hosmer-Lemeshow test was used for assessing the goodness of fit. In the validation cohort, the observed and the predicted incidence were compared by the Chi-square (χ 2 ) goodness of fit test for calibration power. We included 2585 patients in the study, of these 78 patients (3.0%) developed a PU. Between the training and validation groups the patient characteristics were non-significant (p>0.05). In the training group, the logistic regression model for predicting pressure ulcer was Logit(P) = -0.433*Braden score+2.616. The Hosmer-Lemeshow test showed no goodness fit (χ 2 =13.472; p=0.019). In the validation group, the predicted pressure ulcer incidence also did not fit well with the observed incidence (χ 2 =42.154, p=0.000 by Braden scores; and χ 2 =17.223, p=0.001 by Braden scale risk classification). The Braden scale has low calibration power in predicting PU formation.

Experimental advances and preliminary mathematical modeling of the Swiss-roll mixed-reactant direct borohydride fuel cell

NASA Astrophysics Data System (ADS)

Aziznia, Amin; Oloman, Colin W.; Gyenge, Előd L.

2014-11-01

The Swiss-roll single-cell mixed reactant (SR-MRFC) borohydride - oxygen fuel cell equipped with Pt/carbon cloth 3D anode and either MnO2 or Ag gas-diffusion cathodes is investigated by a combination of experimental studies and preliminary mathematical modeling of the polarization curve. We investigate the effects of four variables: cathode side metallic mesh fluid distributor, separator type (Nafion 112® vs. Viledon®), cathode catalyst (MnO2 vs. Ag), and the hydrophilic pore volume fraction of the gas-diffusion cathode. Using a two-phase feed of alkaline borohydride solution (1 M NaBH4 - 2 M NaOH) and O2 gas in an SR-MRFC equipped with Pt/C 3D anode, MnO2 gas diffusion cathode, Viledon® porous diaphragm, expanded mesh cathode-side fluid distributor, the maximum superficial power density is 2230 W m-2 at 323 K and 105 kPa(abs). The latter superficial power density is almost 3.5 times higher than our previously reported superficial power density for the same catalyst combinations. Furthermore, with a Pt anode and Ag cathode catalyst combination, a superficial power density of 2500 W m-2 is achieved with superior performance durability compared to the MnO2 cathode. The fuel cell results are substantiated by impedance spectroscopy analysis and preliminary mathematical model predictions based on mixed potential theory.

Constraining Polarized Foregrounds for EoR Experiments. II. Polarization Leakage Simulations in the Avoidance Scheme

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

Nunhokee, C. D.; Bernardi, G.; Foster, G.

A critical challenge in the observation of the redshifted 21 cm line is its separation from bright Galactic and extragalactic foregrounds. In particular, the instrumental leakage of polarized foregrounds, which undergo significant Faraday rotation as they propagate through the interstellar medium, may harmfully contaminate the 21 cm power spectrum. We develop a formalism to describe the leakage due to instrumental widefield effects in visibility-based power spectra measured with redundant arrays, extending the delay-spectrum approach presented in Parsons et al. We construct polarized sky models and propagate them through the instrument model to simulate realistic full-sky observations with the Precision Arraymore » to Probe the Epoch of Reionization. We find that the leakage due to a population of polarized point sources is expected to be higher than diffuse Galactic polarization at any k mode for a 30 m reference baseline. For the same reference baseline, a foreground-free window at k > 0.3 h Mpc{sup −1} can be defined in terms of leakage from diffuse Galactic polarization even under the most pessimistic assumptions. If measurements of polarized foreground power spectra or a model of polarized foregrounds are given, our method is able to predict the polarization leakage in actual 21 cm observations, potentially enabling its statistical subtraction from the measured 21 cm power spectrum.« less

Using Pre-Melted Phase Change Material to Keep Payloads in Space Warm for Hours without Power

NASA Technical Reports Server (NTRS)

Choi, Michael

2013-01-01

Adding phase change material (PCM) to a mission payload can maintain its temperature above the cold survival limit, without power, for several hours in space. For the International Space Station, PCM is melted by heaters just prior to the payload translation to the worksite when power is available. When power is cut off during the six-hour translation, the PCM releases its latent heat to make up the heat loss from the radiator(s) to space. For the interplanetary Probe, PCM is melted by heaters just prior to separation from the orbiter when power is available from the orbiter power system. After the Probe separates from the orbiter, the PCM releases its latent heat to make up the heat loss from the Probe exterior to space. Paraffin wax is a good PCM candidate.

Peer-to-peer and mass communication effect on opinion shifts

NASA Astrophysics Data System (ADS)

Kindler, A.; Solomon, S.; Stauffer, D.

2013-02-01

Opinion dynamics is studied through a minimal Ising model with three main influences (fields): personal conservatism (power-law distributed), inter-personal and group pressure, and a global field incorporating peer-to-peer and mass communications, which is generated bottom-up from the faction supporting the new opinion. A rich phase diagram appears separating possible terminal stages of the opinion diffusion, characterizing failure phases by the features of the individuals who had changed their opinion. An exhaustive solution of the model is produced, allowing predictions to be made on the opinion’s assimilation in the society.

A self-sensing magnetorheological damper with power generation

NASA Astrophysics Data System (ADS)

Chen, Chao; Liao, Wei-Hsin

2012-02-01

Magnetorheological (MR) dampers are promising for semi-active vibration control of various dynamic systems. In the current MR damper systems, a separate power supply and dynamic sensor are required. To enable the MR damper to be self-powered and self-sensing in the future, in this paper we propose and investigate a self-sensing MR damper with power generation, which integrates energy harvesting, dynamic sensing and MR damping technologies into one device. This MR damper has self-contained power generation and velocity sensing capabilities, and is applicable to various dynamic systems. It combines the advantages of energy harvesting—reusing wasted energy, MR damping—controllable damping force, and sensing—providing dynamic information for controlling system dynamics. This multifunctional integration would bring great benefits such as energy saving, size and weight reduction, lower cost, high reliability, and less maintenance for the MR damper systems. In this paper, a prototype of the self-sensing MR damper with power generation was designed, fabricated, and tested. Theoretical analyses and experimental studies on power generation were performed. A velocity-sensing method was proposed and experimentally validated. The magnetic-field interference among three functions was prevented by a combined magnetic-field isolation method. Modeling, analysis, and experimental results on damping forces are also presented.

Estimates of Power Plant NOx Emissions and Lifetimes from OMI NO2 Satellite Retrievals

NASA Technical Reports Server (NTRS)

de Foy, Benjamin; Lu, Zifeng; Streets, David G.; Lamsal, Lok N.; Duncan, Bryan N.

2015-01-01

Isolated power plants with well characterized emissions serve as an ideal test case of methods to estimate emissions using satellite data. In this study we evaluate the Exponentially-Modified Gaussian (EMG) method and the box model method based on mass balance for estimating known NOx emissions from satellite retrievals made by the Ozone Monitoring Instrument (OMI). We consider 29 power plants in the USA which have large NOx plumes that do not overlap with other sources and which have emissions data from the Continuous Emission Monitoring System (CEMS). This enables us to identify constraints required by the methods, such as which wind data to use and how to calculate background values. We found that the lifetimes estimated by the methods are too short to be representative of the chemical lifetime. Instead, we introduce a separate lifetime parameter to account for the discrepancy between estimates using real data and those that theory would predict. In terms of emissions, the EMG method required averages from multiple years to give accurate results, whereas the box model method gave accurate results for individual ozone seasons.

Preliminary results from a four-working space, double-acting piston, Stirling engine controls model

NASA Technical Reports Server (NTRS)

Daniele, C. J.; Lorenzo, C. F.

1980-01-01

A four working space, double acting piston, Stirling engine simulation is being developed for controls studies. The development method is to construct two simulations, one for detailed fluid behavior, and a second model with simple fluid behaviour but containing the four working space aspects and engine inertias, validate these models separately, then upgrade the four working space model by incorporating the detailed fluid behaviour model for all four working spaces. The single working space (SWS) model contains the detailed fluid dynamics. It has seven control volumes in which continuity, energy, and pressure loss effects are simulated. Comparison of the SWS model with experimental data shows reasonable agreement in net power versus speed characteristics for various mean pressure levels in the working space. The four working space (FWS) model was built to observe the behaviour of the whole engine. The drive dynamics and vehicle inertia effects are simulated. To reduce calculation time, only three volumes are used in each working space and the gas temperature are fixed (no energy equation). Comparison of the FWS model predicted power with experimental data shows reasonable agreement. Since all four working spaces are simulated, the unique capabilities of the model are exercised to look at working fluid supply transients, short circuit transients, and piston ring leakage effects.

Geological Sequestration Training and Research Program in Capture and Transport: Development of the Most Economical Separation Method for CO2 Capture

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

Vahdat, Nader

2013-09-30

The project provided hands-on training and networking opportunities to undergraduate students in the area of carbon dioxide (CO2) capture and transport, through fundamental research study focused on advanced separation methods that can be applied to the capture of CO2 resulting from the combustion of fossil-fuels for power generation . The project team’s approach to achieve its objectives was to leverage existing Carbon Capture and Storage (CCS) course materials and teaching methods to create and implement an annual CCS short course for the Tuskegee University community; conduct a survey of CO2 separation and capture methods; utilize data to verify and developmore » computer models for CO2 capture and build CCS networks and hands-on training experiences. The objectives accomplished as a result of this project were: (1) A comprehensive survey of CO2 capture methods was conducted and mathematical models were developed to compare the potential economics of the different methods based on the total cost per year per unit of CO2 avoidance; and (2) Training was provided to introduce the latest CO2 capture technologies and deployment issues to the university community.« less

Statistical properties of a filtered Poisson process with additive random noise: distributions, correlations and moment estimation

NASA Astrophysics Data System (ADS)

Theodorsen, A.; E Garcia, O.; Rypdal, M.

2017-05-01

Filtered Poisson processes are often used as reference models for intermittent fluctuations in physical systems. Such a process is here extended by adding a noise term, either as a purely additive term to the process or as a dynamical term in a stochastic differential equation. The lowest order moments, probability density function, auto-correlation function and power spectral density are derived and used to identify and compare the effects of the two different noise terms. Monte-Carlo studies of synthetic time series are used to investigate the accuracy of model parameter estimation and to identify methods for distinguishing the noise types. It is shown that the probability density function and the three lowest order moments provide accurate estimations of the model parameters, but are unable to separate the noise types. The auto-correlation function and the power spectral density also provide methods for estimating the model parameters, as well as being capable of identifying the noise type. The number of times the signal crosses a prescribed threshold level in the positive direction also promises to be able to differentiate the noise type.

Requirements for Large Eddy Simulation Computations of Variable-Speed Power Turbine Flows

NASA Technical Reports Server (NTRS)

Ameri, Ali A.

2016-01-01

Variable-speed power turbines (VSPTs) operate at low Reynolds numbers and with a wide range of incidence angles. Transition, separation, and the relevant physics leading to them are important to VSPT flow. Higher fidelity tools such as large eddy simulation (LES) may be needed to resolve the flow features necessary for accurate predictive capability and design of such turbines. A survey conducted for this report explores the requirements for such computations. The survey is limited to the simulation of two-dimensional flow cases and endwalls are not included. It suggests that a grid resolution necessary for this type of simulation to accurately represent the physics may be of the order of Delta(x)+=45, Delta(x)+ =2 and Delta(z)+=17. Various subgrid-scale (SGS) models have been used and except for the Smagorinsky model, all seem to perform well and in some instances the simulations worked well without SGS modeling. A method of specifying the inlet conditions such as synthetic eddy modeling (SEM) is necessary to correctly represent the inlet conditions.

Beam optical design of in-flight fragment separator for high-power heavy ion beam

NASA Astrophysics Data System (ADS)

Yun, C. C.; Kim, Mi-Jung; Kim, D. G.; Song, J. S.; Kim, Myeong-Jin; Kim, J. W.; Kim, J. R.; Wan, W.

2013-12-01

An in-flight fragment separator has been designed for the rare isotope science project (RISP) in Korea. A beam used for the design is 238U in the energy of 200 MeV/u with the maximum beam power of 400 kW. The use of high-power beam requires careful removal of the primary beam by pre-separator, for which its configuration was revised to employ four dipole magnets instead of two. Different configurations of the separator have been tested in search of optimal design in non-linear optics, which was complicated by the space needed for the target, beam dump and radiation shielding. Non-linear optical calculations have been carried out using GICOSY and COSY Infinity including the fringe fields of large-aperture quadrupole magnets. Correction of non-linear terms is made with multipole coils located inside the superconducting quadrupole magnets and by external multipole magnets. Beam simulations using LISE++ and MOCADI have been performed to consider the effects of multiple charge states of the primary and isotope beams produced at the target. Layout of the separator is being finalized, and detailed optics simulation will continue to refine its design.

Micropower Mixed-signal VLSI Independent Component Analysis for Gradient Flow Acoustic Source Separation.

PubMed

Stanaćević, Milutin; Li, Shuo; Cauwenberghs, Gert

2016-07-01

A parallel micro-power mixed-signal VLSI implementation of independent component analysis (ICA) with reconfigurable outer-product learning rules is presented. With the gradient sensing of the acoustic field over a miniature microphone array as a pre-processing method, the proposed ICA implementation can separate and localize up to 3 sources in mild reverberant environment. The ICA processor is implemented in 0.5 µm CMOS technology and occupies 3 mm × 3 mm area. At 16 kHz sampling rate, ASIC consumes 195 µW power from a 3 V supply. The outer-product implementation of natural gradient and Herault-Jutten ICA update rules demonstrates comparable performance to benchmark FastICA algorithm in ideal conditions and more robust performance in noisy and reverberant environment. Experiments demonstrate perceptually clear separation and precise localization over wide range of separation angles of two speech sources presented through speakers positioned at 1.5 m from the array on a conference room table. The presented ASIC leads to a extreme small form factor and low power consumption microsystem for source separation and localization required in applications like intelligent hearing aids and wireless distributed acoustic sensor arrays.

Applying the Expectancy-Value Model to understand health values.

PubMed

Zhang, Xu-Hao; Xie, Feng; Wee, Hwee-Lin; Thumboo, Julian; Li, Shu-Chuen

2008-03-01

Expectancy-Value Model (EVM) is the most structured model in psychology to predict attitudes by measuring attitudinal attributes (AAs) and relevant external variables. Because health value could be categorized as attitude, we aimed to apply EVM to explore its usefulness in explaining variances in health values and investigate underlying factors. Focus group discussion was carried out to identify the most common and significant AAs toward 5 different health states (coded as 11111, 11121, 21221, 32323, and 33333 in EuroQol Five-Dimension (EQ-5D) descriptive system). AAs were measured in a sum of multiplications of subjective probability (expectancy) and perceived value of attributes with 7-point Likert scales. Health values were measured using visual analog scales (VAS, range 0-1). External variables (age, sex, ethnicity, education, housing, marital status, and concurrent chronic diseases) were also incorporated into survey questionnaire distributed by convenience sampling among eligible respondents. Univariate analyses were used to identify external variables causing significant differences in VAS. Multiple linear regression model (MLR) and hierarchical regression model were used to investigate the explanatory power of AAs and possible significant external variable(s) separately or in combination, for each individual health state and a mixed scenario of five states, respectively. Four AAs were identified, namely, "worsening your quality of life in terms of health" (WQoL), "adding a burden to your family" (BTF), "making you less independent" (MLI) and "unable to work or study" (UWS). Data were analyzed based on 232 respondents (mean [SD] age: 27.7 [15.07] years, 49.1% female). Health values varied significantly across 5 health states, ranging from 0.12 (33333) to 0.97 (11111). With no significant external variables identified, EVM explained up to 62% of the variances in health values across 5 health states. The explanatory power of 4 AAs were found to be between 13% and 28% in separate MLR models (P < 0.05). When data were analyzed for each health state, variances in health values became small and explanatory power of EVM was reduced to a range between 8% and 23%. EVM was useful in explaining variances of health values and predicting important factors. Its power to explain small variances might be restricted due to limitations of 7-point Likert scale to measure AAs accurately. With further improvement and validation of a compatible continuous scale for more accurate measurement, EVM is expected to explain health values to a larger extent.

A complex-lamellar description of boundary layer transition

NASA Astrophysics Data System (ADS)

Kolla, Maureen Louise

Flow transition is important, in both practical and phenomenological terms. However, there is currently no method for identifying the spatial locations associated with transition, such as the start and end of intermittency. The concept of flow stability and experimental correlations have been used, however, flow stability only identifies the location where disturbances begin to grow in the laminar flow and experimental correlations can only give approximations as measuring the start and end of intermittency is difficult. Therefore, the focus of this work is to construct a method to identify the start and end of intermittency, for a natural boundary layer transition and a separated flow transition. We obtain these locations by deriving a complex-lamellar description of the velocity field that exists between a fully laminar and fully turbulent boundary condition. Mathematically, this complex-lamellar decomposition, which is constructed from the classical Darwin-Lighthill-Hawthorne drift function and the transport of enstrophy, describes the flow that exists between the fully laminar Pohlhausen equations and Prandtl's fully turbulent one seventh power law. We approximate the difference in enstrophy density between the boundary conditions using a power series. The slope of the power series is scaled by using the shape of the universal intermittency distribution within the intermittency region. We solve the complex-lamellar decomposition of the velocity field along with the slope of the difference in enstrophy density function to determine the location of the laminar and turbulent boundary conditions. Then from the difference in enstrophy density function we calculate the start and end of intermittency. We perform this calculation on a natural boundary layer transition over a flat plate for zero pressure gradient flow and for separated shear flow over a separation bubble. We compare these results to existing experimental results and verify the accuracy of our transition model.

14 CFR 25.1707 - System separation: EWIS.

Code of Federal Regulations, 2013 CFR

2013-01-01

... installed to ensure adequate physical separation and electrical isolation so that damage to circuits... ensure adequate physical separation and electrical isolation so that a fault in any one airplane power... minimize potential for abrasion/chafing, vibration damage, and other types of mechanical damage. ...

14 CFR 25.1707 - System separation: EWIS.

Code of Federal Regulations, 2014 CFR

2014-01-01

... installed to ensure adequate physical separation and electrical isolation so that damage to circuits... ensure adequate physical separation and electrical isolation so that a fault in any one airplane power... minimize potential for abrasion/chafing, vibration damage, and other types of mechanical damage. ...

14 CFR 25.1707 - System separation: EWIS.

Code of Federal Regulations, 2010 CFR

2010-01-01

... installed to ensure adequate physical separation and electrical isolation so that damage to circuits... ensure adequate physical separation and electrical isolation so that a fault in any one airplane power... minimize potential for abrasion/chafing, vibration damage, and other types of mechanical damage. ...

14 CFR 25.1707 - System separation: EWIS.

Code of Federal Regulations, 2012 CFR

2012-01-01

... installed to ensure adequate physical separation and electrical isolation so that damage to circuits... ensure adequate physical separation and electrical isolation so that a fault in any one airplane power... minimize potential for abrasion/chafing, vibration damage, and other types of mechanical damage. ...

14 CFR 25.1707 - System separation: EWIS.

Code of Federal Regulations, 2011 CFR

2011-01-01

... installed to ensure adequate physical separation and electrical isolation so that damage to circuits... ensure adequate physical separation and electrical isolation so that a fault in any one airplane power... minimize potential for abrasion/chafing, vibration damage, and other types of mechanical damage. ...

Projected electric power demands for the Potomac Electric Power Company. Volume 1

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

Estomin, S.; Kahal, M.

1984-03-01

This three-volume report presents the results of an econometric forecast of peak and electric power demands for the Potomac Electric Power Company (PEPCO) through the year 2002. Volume I describes the methodology, the results of the econometric estimations, the forecast assumptions and the calculated forecasts of peak demand and energy usage. Separate sets of models were developed for the Maryland Suburbs (Montgomery and Prince George's counties), the District of Columbia and Southern Maryland (served by a wholesale customer of PEPCO). For each of the three jurisdictions, energy equations were estimated for residential and commercial/industrial customers for both summer and wintermore » seasons. For the District of Columbia, summer and winter equations for energy sales to the federal government were also estimated. Equations were also estimated for street lighting and energy losses. Noneconometric techniques were employed to forecast energy sales to the Northern Virginia suburbs, Metrorail and federal government facilities located in Maryland.« less

INDIVIDUAL-BASED MODELS: POWERFUL OR POWER STRUGGLE?

PubMed

Willem, L; Stijven, S; Hens, N; Vladislavleva, E; Broeckhove, J; Beutels, P

2015-01-01

Individual-based models (IBMs) offer endless possibilities to explore various research questions but come with high model complexity and computational burden. Large-scale IBMs have become feasible but the novel hardware architectures require adapted software. The increased model complexity also requires systematic exploration to gain thorough system understanding. We elaborate on the development of IBMs for vaccine-preventable infectious diseases and model exploration with active learning. Investment in IBM simulator code can lead to significant runtime reductions. We found large performance differences due to data locality. Sorting the population once, reduced simulation time by a factor two. Storing person attributes separately instead of using person objects also seemed more efficient. Next, we improved model performance up to 70% by structuring potential contacts based on health status before processing disease transmission. The active learning approach we present is based on iterative surrogate modelling and model-guided experimentation. Symbolic regression is used for nonlinear response surface modelling with automatic feature selection. We illustrate our approach using an IBM for influenza vaccination. After optimizing the parameter spade, we observed an inverse relationship between vaccination coverage and the clinical attack rate reinforced by herd immunity. These insights can be used to focus and optimise research activities, and to reduce both dimensionality and decision uncertainty.

Impacts of Extreme Space Weather Events on Power Grid Infrastructure: Physics-Based Modelling of Geomagnetically-Induced Currents (GICs) During Carrington-Class Geomagnetic Storms

NASA Astrophysics Data System (ADS)

Henderson, M. G.; Bent, R.; Chen, Y.; Delzanno, G. L.; Jeffery, C. A.; Jordanova, V. K.; Morley, S.; Rivera, M. K.; Toth, G.; Welling, D. T.; Woodroffe, J. R.; Engel, M.

2017-12-01

Large geomagnetic storms can have devastating effects on power grids. The largest geomagnetic storm ever recorded - called the Carrington Event - occurred in 1859 and produced Geomagnetically Induced Currents (GICs) strong enough to set fires in telegraph offices. It has been estimated that if such a storm occurred today, it would have devastating, long-lasting effects on the North American power transmission infrastructure. Acutely aware of this imminent threat, the North American Electric Reliability Corporation (NERC) was recently instructed to establish requirements for transmission system performance during geomagnetic disturbance (GMD) events and, although the benchmarks adopted were based on the best available data at the time, they suffer from a severely limited physical understanding of the behavior of GMDs and the resulting GICs for strong events. To rectify these deficiencies, we are developing a first-of-its-kind data-informed modelling capability that will provide transformational understanding of the underlying physical mechanisms responsible for the most harmful intense localized GMDs and their impacts on real power transmission networks. This work is being conducted in two separate modes of operation: (1) using historical, well-observed large storm intervals for which robust data-assimilation can be performed, and (2) extending the modelling into a predictive realm in order to assess impacts of poorly and/or never-before observed Carrington-class events. Results of this work are expected to include a potential replacement for the current NERC benchmarking methodology and the development of mitigation strategies in real power grid networks. We report on progress to date and show some preliminary results of modeling large (but not yet extreme) events.

Epoch of reionization 21 cm forecasting from MCMC-constrained semi-numerical models

NASA Astrophysics Data System (ADS)

Hassan, Sultan; Davé, Romeel; Finlator, Kristian; Santos, Mario G.

2017-06-01

The recent low value of Planck Collaboration XLVII integrated optical depth to Thomson scattering suggests that the reionization occurred fairly suddenly, disfavouring extended reionization scenarios. This will have a significant impact on the 21 cm power spectrum. Using a semi-numerical framework, we improve our model from instantaneous to include time-integrated ionization and recombination effects, and find that this leads to more sudden reionization. It also yields larger H II bubbles that lead to an order of magnitude more 21 cm power on large scales, while suppressing the small-scale ionization power. Local fluctuations in the neutral hydrogen density play the dominant role in boosting the 21 cm power spectrum on large scales, while recombinations are subdominant. We use a Monte Carlo Markov chain approach to constrain our model to observations of the star formation rate functions at z = 6, 7, 8 from Bouwens et al., the Planck Collaboration XLVII optical depth measurements and the Becker & Bolton ionizing emissivity data at z ˜ 5. We then use this constrained model to perform 21 cm forecasting for Low Frequency Array, Hydrogen Epoch of Reionization Array and Square Kilometre Array in order to determine how well such data can characterize the sources driving reionization. We find that the Mock 21 cm power spectrum alone can somewhat constrain the halo mass dependence of ionizing sources, the photon escape fraction and ionizing amplitude, but combining the Mock 21 cm data with other current observations enables us to separately constrain all these parameters. Our framework illustrates how the future 21 cm data can play a key role in understanding the sources and topology of reionization as observations improve.

PV-Diesel Hybrid SCADA Experiment Network Design

NASA Technical Reports Server (NTRS)

Kalu, Alex; Durand, S.; Emrich, Carol; Ventre, G.; Wilson, W.; Acosta, R.

1999-01-01

The essential features of an experimental network for renewable power system satellite based supervisory, control and data acquisition (SCADA) are communication links, controllers, diagnostic equipment and a hybrid power system. Required components for implementing the network consist of two satellite ground stations, to satellite modems, two 486 PCs, two telephone receivers, two telephone modems, two analog telephone lines, one digital telephone line, a hybrid-power system equipped with controller and a satellite spacecraft. In the technology verification experiment (TVE) conducted by Savannah State University and Florida Solar Energy Center, the renewable energy hybrid system is the Apex-1000 Mini-Hybrid which is equipped with NGC3188 for user interface and remote control and the NGC2010 for monitoring and basic control tasks. This power system is connected to a satellite modem via a smart interface, RS232. Commands are sent to the power system control unit through a control PC designed as PC1. PC1 is thus connected to a satellite model through RS232. A second PC, designated PC2, the diagnostic PC is connected to both satellite modems via separate analog telephone lines for checking modems'health. PC2 is also connected to PC1 via a telephone line. Due to the unavailability of a second ground station for the ACTS, one ground station is used to serve both the sending and receiving functions in this experiment. Signal is sent from the control PC to the Hybrid system at a frequency f(sub 1), different from f(sub 2), the signal from the hybrid system to the control PC. f(sub l) and f(sub 2) are sufficiently separated to avoid interference.

THE FUNDAMENTAL SOLUTIONS FOR MULTI-TERM MODIFIED POWER LAW WAVE EQUATIONS IN A FINITE DOMAIN.

PubMed

Jiang, H; Liu, F; Meerschaert, M M; McGough, R J

2013-01-01

Fractional partial differential equations with more than one fractional derivative term in time, such as the Szabo wave equation, or the power law wave equation, describe important physical phenomena. However, studies of these multi-term time-space or time fractional wave equations are still under development. In this paper, multi-term modified power law wave equations in a finite domain are considered. The multi-term time fractional derivatives are defined in the Caputo sense, whose orders belong to the intervals (1, 2], [2, 3), [2, 4) or (0, n ) ( n > 2), respectively. Analytical solutions of the multi-term modified power law wave equations are derived. These new techniques are based on Luchko's Theorem, a spectral representation of the Laplacian operator, a method of separating variables and fractional derivative techniques. Then these general methods are applied to the special cases of the Szabo wave equation and the power law wave equation. These methods and techniques can also be extended to other kinds of the multi-term time-space fractional models including fractional Laplacian.

Beam Wave Considerations for Optical Link Budget Calculations

NASA Technical Reports Server (NTRS)

Manning, Robert M.

2016-01-01

The bounded beam wave nature of electromagnetic radiation emanating from a finite size aperture is considered for diffraction-based link power budget calculations for an optical communications system. Unlike at radio frequency wavelengths, diffraction effects are very important at optical wavelengths. In the general case, the situation cannot be modeled by supposing isotropic radiating antennas and employing the concept of effective isotropic radiated power. It is shown here, however, that these considerations are no more difficult to treat than spherical-wave isotopic based calculations. From first principles, a general expression governing the power transfer for a collimated beam wave is derived and from this are defined the three regions of near-field, first Fresnel zone, and far-field behavior. Corresponding equations for the power transfer are given for each region. It is shown that although the well-known linear expressions for power transfer in the far-field hold for all distances between source and receiver in the radio frequency case, nonlinear behavior within the first Fresnel zone must be accounted for in the optical case at 1550 nm with typical aperture sizes at source/receiver separations less that 100 km.

Resilient guaranteed cost control of a power system.

PubMed

Soliman, Hisham M; Soliman, Mostafa H; Hassan, Mohammad F

2014-05-01

With the development of power system interconnection, the low-frequency oscillation is becoming more and more prominent which may cause system separation and loss of energy to consumers. This paper presents an innovative robust control for power systems in which the operating conditions are changing continuously due to load changes. However, practical implementation of robust control can be fragile due to controller inaccuracies (tolerance of resistors used with operational amplifiers). A new design of resilient (non-fragile) robust control is given that takes into consideration both model and controller uncertainties by an iterative solution of a set of linear matrix inequalities (LMI). Both uncertainties are cast into a norm-bounded structure. A sufficient condition is derived to achieve the desired settling time for damping power system oscillations in face of plant and controller uncertainties. Furthermore, an improved controller design, resilient guaranteed cost controller, is derived to achieve oscillations damping in a guaranteed cost manner. The effectiveness of the algorithm is shown for a single machine infinite bus system, and then, it is extended to multi-area power system.

Nonlinear force propagation, anisotropic stiffening and non-affine relaxation in a model cytoskeleton

NASA Astrophysics Data System (ADS)

Mizuno, Daisuke; Head, David; Ikebe, Emi; Nakamasu, Akiko; Kinoshita, Suguru; Peijuan, Zhang; Ando, Shoji

2013-03-01

Forces are generated heterogeneously in living cells and transmitted through cytoskeletal networks that respond highly non-linearly. Here, we carry out high-bandwidth passive microrheology on vimentin networks reconstituted in vitro, and observe the nonlinear mechanical response due to forces propagating from a local source applied by an optical tweezer. Since the applied force is constant, the gel becomes equilibrated and the fluctuation-dissipation theorem can be employed to deduce the viscoelasticity of the local environment from the thermal fluctuations of colloidal probes. Our experiments unequivocally demonstrate the anisotropic stiffening of the cytoskeletal network behind the applied force, with greater stiffening in the parallel direction. Quantitative agreement with an affine continuum model is obtained, but only for the response at certain frequency ~ 10-1000 Hz which separates the high-frequency power law and low-frequency elastic behavior of the network. We argue that the failure of the model at lower frequencies is due to the presence of non-affinity, and observe that zero-frequency changes in particle separation can be fitted when an independently-measured, empirical nonaffinity factor is applied.

Launch Vehicle Propulsion Design with Multiple Selection Criteria

NASA Technical Reports Server (NTRS)

Shelton, Joey D.; Frederick, Robert A.; Wilhite, Alan W.

2005-01-01

The approach and techniques described herein define an optimization and evaluation approach for a liquid hydrogen/liquid oxygen single-stage-to-orbit system. The method uses Monte Carlo simulations, genetic algorithm solvers, a propulsion thermo-chemical code, power series regression curves for historical data, and statistical models in order to optimize a vehicle system. The system, including parameters for engine chamber pressure, area ratio, and oxidizer/fuel ratio, was modeled and optimized to determine the best design for seven separate design weight and cost cases by varying design and technology parameters. Significant model results show that a 53% increase in Design, Development, Test and Evaluation cost results in a 67% reduction in Gross Liftoff Weight. Other key findings show the sensitivity of propulsion parameters, technology factors, and cost factors and how these parameters differ when cost and weight are optimized separately. Each of the three key propulsion parameters; chamber pressure, area ratio, and oxidizer/fuel ratio, are optimized in the seven design cases and results are plotted to show impacts to engine mass and overall vehicle mass.

Research and exploration of product innovative design for function

NASA Astrophysics Data System (ADS)

Wang, Donglin; Wei, Zihui; Wang, Youjiang; Tan, Runhua

2009-07-01

Products innovation is under the prerequisite of realizing the new function, the realization of the new function must solve the contradiction. A new process model of new product innovative design was proposed based on Axiomatic Design (AD) Theory and Functional Structure Analysis (FSA), imbedded Principle of Solving Contradiction. In this model, employ AD Theory to guide FSA, determine the contradiction for the realization of the principle solution. To provide powerful support for innovative design tools in principle solution, Principle of Solving Contradiction in the model were imbedded, so as to boost up the innovation of principle solution. As a case study, an innovative design of button battery separator paper punching machine has been achieved with application of the proposed model.

Experimental study of separator effect and shift angle on crossflow wind turbine performance

NASA Astrophysics Data System (ADS)

Fahrudin, Tjahjana, Dominicus Danardono Dwi Prija; Santoso, Budi

2018-02-01

This paper present experimental test results of separator and shift angle influence on Crossflow vertical axis wind turbine. Modification by using a separator and shift angle is expected to improve the thrust on the blade so as to improve the efficiency. The design of the wind turbine is tested at different wind speeds. There are 2 variations of crossflow turbine design which will be analyzed using an experimental test scheme that is, 3 stage crossflow and 2 stage crossflow with the shift angle. Maximum power coefficient obtained as Cpmax = 0.13 at wind speed 4.05 m/s for 1 separator and Cpmax = 0.12 for 12° shear angle of wind speed 4.05 m/s. In this study, power characteristics of the crossflow rotor with separator and shift angle have been tested. The experimental data was collected by variation of 2 separator and shift angle 0°, 6°, 12° and wind speed 3.01 - 4.85 m/s.

49 CFR 236.516 - Power supply.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 49 Transportation 4 2011-10-01 2011-10-01 false Power supply. 236.516 Section 236.516..., Train Control and Cab Signal Systems Standards § 236.516 Power supply. Automatic cab signal, train stop, or train control device hereafter installed shall operate from a separate or isolated power supply...

49 CFR 236.516 - Power supply.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 49 Transportation 4 2010-10-01 2010-10-01 false Power supply. 236.516 Section 236.516..., Train Control and Cab Signal Systems Standards § 236.516 Power supply. Automatic cab signal, train stop, or train control device hereafter installed shall operate from a separate or isolated power supply...

Aerodynamics of powered missile separation from F/A-18 aircraft

NASA Technical Reports Server (NTRS)

Ahmad, J. U.; Shanks, S. P.; Buning, P. G.

1993-01-01

A 3D dynamic 'chimera' algorithm that solves the thin-layer Navier-Stokes equations over multiple moving bodies was modified to numerically simulate the aerodynamics, missile dynamics, and missile plume interactions of a missile separating from a generic wing and from an F/A-18 aircraft in transonic flow. The missile is mounted below the wing for missile separation from the wing and on the F/A-18 fuselage at the engine inlet side for missile separation from aircraft. Static and powered missile separation cases are considered to examine the influence of the missile and plume on the wing and F/A-18 fuselage and engine inlet. The aircraft and missile are at two degrees angle of attack, Reynolds number of 10 million, freestream Mach number of 1.05 and plume Mach number of 3.0. The computational results show the details of the flow field.

Polypropylene/hydrophobic-silica-aerogel-composite separator induced enhanced safety and low polarization for lithium-ion batteries

NASA Astrophysics Data System (ADS)

Feng, Guanhua; Li, Zihe; Mi, Liwei; Zheng, Jinyun; Feng, Xiangming; Chen, Weihua

2018-02-01

Separator as an important part of lithium-ion batteries, allowing the ion to transfer and preventing the direct contact of anode with cathode, determines the safety of the batteries. In this work, a kind of polypropylene/hydrophobic silica-aerogel-composite (SAC) separator is fabricated through combining hydrophobic silica aerogel and polypropylene (PP) separator. The rationally designed SAC effectively increases the thermal stability of the separator with slightly growing weight (the area retention rate is 30% higher than that of the PP separator after being heated for 30 min at 160 °C). In addition, the hydrophobic silica aerogel layer in SAC significantly improves the wettability of PP separator to electrolyte owning to the introduced hydrophobic functional groups of -Si(CH3)3 and porous structure, and the contact angles of SAC separator to several common organic electrolytes (EC/DMC, DMC/DOL, Diglyme) are close to 0°. Electrochemical tests show that the prepared SAC separator can decrease the polarization of Li-ion batteries and leads to improved power performance and cycle stability. And the SAC separator is firm with neglectable abscission after folding 200 times. This work provides a new way to improve the safety and simultaneously reduce the polarization of the batteries, implying promising application potential in power batteries.

Power-Amplifier Module for 145 to 165 GHz

NASA Technical Reports Server (NTRS)

Samoska, Lorene; Peralta, Alejandro

2007-01-01

A power-amplifier module that operates in the frequency range of 145 to 165 GHz has been designed and constructed as a combination of (1) a previously developed monolithic microwave integrated circuit (MMIC) power amplifier and (2) a waveguide module. The amplifier chip was needed for driving a high-electron-mobility-transistor (HEMT) frequency doubler. While it was feasible to connect the amplifier and frequency-doubler chips by use of wire bonds, it was found to be much more convenient to test the amplifier and doubler chips separately. To facilitate separate testing, it was decided to package the amplifier and doubler chips in separate waveguide modules. Figure 1 shows the resulting amplifier module. The amplifier chip was described in "MMIC HEMT Power Amplifier for 140 to 170 GHz" (NPO-30127), NASA Tech Briefs, Vol. 27, No. 11, (November 2003), page 49. To recapitulate: This is a three-stage MMIC power amplifier that utilizes HEMTs as gain elements. The amplifier was originally designed to operate in the frequency range of 140 to 170 GHz. The waveguide module is based on a previously developed lower frequency module, redesigned to support operation in the frequency range of 140 to 220 GHz. Figure 2 presents results of one of several tests of the amplifier module - measurements of output power and gain as functions of input power at an output frequency of 150 GHz. Such an amplifier module has many applications to test equipment for power sources above 100 GHz.

Source apportionment of fine particulate matter in China in 2013 using a source-oriented chemical transport model.

PubMed

Shi, Zhihao; Li, Jingyi; Huang, Lin; Wang, Peng; Wu, Li; Ying, Qi; Zhang, Hongliang; Lu, Li; Liu, Xuejun; Liao, Hong; Hu, Jianlin

2017-12-01

China has been suffering high levels of fine particulate matter (PM 2.5 ). Designing effective PM 2.5 control strategies requires information about the contributions of different sources. In this study, a source-oriented Community Multiscale Air Quality (CMAQ) model was applied to quantitatively estimate the contributions of different source sectors to PM 2.5 in China. Emissions of primary PM 2.5 and gas pollutants of SO 2 , NO x , and NH 3 , which are precursors of particulate sulfate, nitrate, and ammonium (SNA, major PM 2.5 components in China), from eight source categories (power plants, residential sources, industries, transportation, open burning, sea salt, windblown dust and agriculture) were separately tracked to determine their contributions to PM 2.5 in 2013. Industrial sector is the largest source of SNA in Beijing, Xi'an and Chongqing, followed by agriculture and power plants. Residential emissions are also important sources of SNA, especially in winter when severe pollution events often occur. Nationally, the contributions of different source sectors to annual total PM 2.5 from high to low are industries, residential sources, agriculture, power plants, transportation, windblown dust, open burning and sea salt. Provincially, residential sources and industries are the major anthropogenic sources of primary PM 2.5 , while industries, agriculture, power plants and transportation are important for SNA in most provinces. For total PM 2.5 , residential and industrial emissions are the top two sources, with a combined contribution of 40-50% in most provinces. The contributions of power plants and agriculture to total PM 2.5 are about 10%, respectively. Secondary organic aerosol accounts for about 10% of annual PM 2.5 in most provinces, with higher contributions in southern provinces such as Yunnan (26%), Hainan (25%) and Taiwan (21%). Windblown dust is an important source in western provinces such as Xizang (55% of total PM 2.5 ), Qinghai (74%), Xinjiang (59%). The large variation in sources of PM 2.5 across China suggests that PM 2.5 mitigation programs should be designed separately for different regions/provinces. Copyright © 2017 Elsevier B.V. All rights reserved.

Structural Embeddings: Mechanization with Method

NASA Technical Reports Server (NTRS)

Munoz, Cesar; Rushby, John

1999-01-01

The most powerful tools for analysis of formal specifications are general-purpose theorem provers and model checkers, but these tools provide scant methodological support. Conversely, those approaches that do provide a well-developed method generally have less powerful automation. It is natural, therefore, to try to combine the better-developed methods with the more powerful general-purpose tools. An obstacle is that the methods and the tools often employ very different logics. We argue that methods are separable from their logics and are largely concerned with the structure and organization of specifications. We, propose a technique called structural embedding that allows the structural elements of a method to be supported by a general-purpose tool, while substituting the logic of the tool for that of the method. We have found this technique quite effective and we provide some examples of its application. We also suggest how general-purpose systems could be restructured to support this activity better.

4 Gbps Scalable Low-Voltage Signaling (SLVS) transceiver for pixel radiation detectors

NASA Astrophysics Data System (ADS)

Kadlubowski, Lukasz A.; Kmon, Piotr

2017-08-01

We report on the design of 4 Gbps Scalable Low-Voltage Signaling (SLVS) transceiver in 40nm CMOS technology for application-specific integrated circuits (ASICs) dedicated to pixel radiation detectors. Serial data are transmitted with +/-200mV differential swing around 200mV nominal common-mode level. The common-mode interference minimization is crucial in such a design, due to EMC requirements. For multi-gigabit-per-second speeds, the influence of power supply path becomes one of the most challenging design issues. Accurate modeling of supply pads at each step of the design is necessary. Our analysis shows that the utilization of multiple bond wires as well as separate power supply pads for bulk terminals connection of the transistors is essential to ensure proper operation of the transceiver. The design is a result of various trade-offs between speed, required operating conditions, common-mode interference as well as power and area consumption.

Surface acoustical intensity measurements on a diesel engine

NASA Technical Reports Server (NTRS)

Mcgary, M. C.; Crocker, M. J.

1980-01-01

The use of surface intensity measurements as an alternative to the conventional selective wrapping technique of noise source identification and ranking on diesel engines was investigated. A six cylinder, in line turbocharged, 350 horsepower diesel engine was used. Sound power was measured under anechoic conditions for eight separate parts of the engine at steady state operating conditions using the conventional technique. Sound power measurements were repeated on five separate parts of the engine using the surface intensity at the same steady state operating conditions. The results were compared by plotting sound power level against frequency and noise source rankings for the two methods.

Simultaneous detection of 19 K-ras mutations by free-solution conjugate electrophoresis of ligase detection reaction products on glass microchips

PubMed Central

Albrecht, Jennifer Coyne; Kotani, Akira; Lin, Jennifer S.; Soper, Steven A.; Barron, Annelise E.

2015-01-01

We demonstrate here the power and flexibility of free-solution conjugate electrophoresis (FSCE) as a method of separating DNA fragments by electrophoresis with no sieving polymer network. Previous work introduced the coupling of FSCE with ligase detection reaction (LDR) to detect point mutations, even at low abundance compared to the wild-type DNA. Here, four large drag-tags are used to achieve free-solution electrophoretic separation of 19 LDR products ranging in size from 42–66 nt that correspond to mutations in the K-ras oncogene. LDR-FSCE enabled electrophoretic resolution of these 19 LDR-FSCE products by CE in 13.5 minutes (E = 310 V/cm) and by microchip electrophoresis in 140 seconds (E = 350 V/cm). The power of FSCE is demonstrated in the unique characteristic of free-solution separations where the separation resolution is constant no matter the electric field strength. By microchip electrophoresis, the electric field was increased to the maximum of the power supply (E = 700 V/cm), and the 19 LDR-FSCE products were separated in < 70 seconds with almost identical resolution to the separation at E = 350 V/cm. These results will aid the goal of screening K-ras mutations on integrated “sample-in/answer-out” devices with amplification, LDR, and detection all on one platform. PMID:23192597

The performance and long-term stability of low-cost separators in single-chamber bottle-type microbial fuel cells.

PubMed

Kondaveeti, Sanath; Kakarla, Ramesh; Kim, Hong Suck; Kim, Byung-Goon; Min, Booki

2018-02-01

This study evaluates long-term stability of low-cost separators in single-chamber bottle-type microbial fuel cells with domestic wastewater. Low-cost separators tested in this study were nonwoven fabrics (NWF) of polypropylene (PP80, PP100), textile fabrics of polyphenylene sulfide (PPS), sulfonated polyphenylene sulfide (SPPS), and cellulose esters. NWF PP80 separator generated the highest power density of 280 mW/m 2 , which was higher than with ion-exchange membranes (cation exchange membrane; CEM = 271 mW/m 2 , cation exchange membrane; CMI = 196 mW/m 2 , Nafion = 260 mW/m 2 ). MFC operations with other size-selective separators such as SPPS, PPS, and cellulose esters exhibited power densities of 261, 231, and 250 mW/m 2 , respectively. During a 280-day operation, initial power density of PP80 (278 mW/m 2 ) was decreased to 257 mW/m 2 , but this decrease was smaller than with others (Nafion: 265-230 mW/m 2 ; PP100: 220-126 mW/m 2 ). The anode potential of around -430 mV did not change much with all separators in the long-term operation, but the initial cathode potential gradually decreased. Fouling analysis suggested that the presence of carbonaceous substance on Nafion and PP80 after 280 days of operation and Nafion was subject to be more biofouling.

Coupling extended magnetohydrodynamic fluid codes with radiofrequency ray tracing codes for fusion modeling

NASA Astrophysics Data System (ADS)

Jenkins, Thomas G.; Held, Eric D.

2015-09-01

Neoclassical tearing modes are macroscopic (L ∼ 1 m) instabilities in magnetic fusion experiments; if unchecked, these modes degrade plasma performance and may catastrophically destroy plasma confinement by inducing a disruption. Fortunately, the use of properly tuned and directed radiofrequency waves (λ ∼ 1 mm) can eliminate these modes. Numerical modeling of this difficult multiscale problem requires the integration of separate mathematical models for each length and time scale (Jenkins and Kruger, 2012 [21]); the extended MHD model captures macroscopic plasma evolution while the RF model tracks the flow and deposition of injected RF power through the evolving plasma profiles. The scale separation enables use of the eikonal (ray-tracing) approximation to model the RF wave propagation. In this work we demonstrate a technique, based on methods of computational geometry, for mapping the ensuing RF data (associated with discrete ray trajectories) onto the finite-element/pseudospectral grid that is used to model the extended MHD physics. In the new representation, the RF data can then be used to construct source terms in the equations of the extended MHD model, enabling quantitative modeling of RF-induced tearing mode stabilization. Though our specific implementation uses the NIMROD extended MHD (Sovinec et al., 2004 [22]) and GENRAY RF (Smirnov et al., 1994 [23]) codes, the approach presented can be applied more generally to any code coupling requiring the mapping of ray tracing data onto Eulerian grids.

Advanced Technology Training System on Motor-Operated Valves

NASA Technical Reports Server (NTRS)

Wiederholt, Bradley J.; Widjaja, T. Kiki; Yasutake, Joseph Y.; Isoda, Hachiro

1993-01-01

This paper describes how features from the field of Intelligent Tutoring Systems are applied to the Motor-Operated Valve (MOV) Advanced Technology Training System (ATTS). The MOV ATTS is a training system developed at Galaxy Scientific Corporation for the Central Research Institute of Electric Power Industry in Japan and the Electric Power Research Institute in the United States. The MOV ATTS combines traditional computer-based training approaches with system simulation, integrated expert systems, and student and expert modeling. The primary goal of the MOV ATTS is to reduce human errors that occur during MOV overhaul and repair. The MOV ATTS addresses this goal by providing basic operational information of the MOV, simulating MOV operation, providing troubleshooting practice of MOV failures, and tailoring this training to the needs of each individual student. The MOV ATTS integrates multiple expert models (functional and procedural) to provide advice and feedback to students. The integration also provides expert model validation support to developers. Student modeling is supported by two separate student models: one model registers and updates the student's current knowledge of basic MOV information, while another model logs the student's actions and errors during troubleshooting exercises. These two models are used to provide tailored feedback to the student during the MOV course.

Axial cervical vertebrae-based multivariate regression model for the estimation of skeletal-maturation status.

PubMed

Yang, Y-M; Lee, J; Kim, Y-I; Cho, B-H; Park, S-B

2014-08-01

This study aimed to determine the viability of using axial cervical vertebrae (ACV) as biological indicators of skeletal maturation and to build models that estimate ossification level with improved explanatory power over models based only on chronological age. The study population comprised 74 female and 47 male patients with available hand-wrist radiographs and cone-beam computed tomography images. Generalized Procrustes analysis was used to analyze the shape, size, and form of the ACV regions of interest. The variabilities of these factors were analyzed by principal component analysis. Skeletal maturation was then estimated using a multiple regression model. Separate models were developed for male and female participants. For the female estimation model, the adjusted R(2) explained 84.8% of the variability of the Sempé maturation level (SML), representing a 7.9% increase in SML explanatory power over that using chronological age alone (76.9%). For the male estimation model, the adjusted R(2) was over 90%, representing a 1.7% increase relative to the reference model. The simplest possible ACV morphometric information provided a statistically significant explanation of the portion of skeletal-maturation variability not dependent on chronological age. These results verify that ACV is a strong biological indicator of ossification status. © 2014 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Augmenting the logrank test in the design of clinical trials in which non-proportional hazards of the treatment effect may be anticipated.

PubMed

Royston, Patrick; Parmar, Mahesh K B

2016-02-11

Most randomized controlled trials with a time-to-event outcome are designed assuming proportional hazards (PH) of the treatment effect. The sample size calculation is based on a logrank test. However, non-proportional hazards are increasingly common. At analysis, the estimated hazards ratio with a confidence interval is usually presented. The estimate is often obtained from a Cox PH model with treatment as a covariate. If non-proportional hazards are present, the logrank and equivalent Cox tests may lose power. To safeguard power, we previously suggested a 'joint test' combining the Cox test with a test of non-proportional hazards. Unfortunately, a larger sample size is needed to preserve power under PH. Here, we describe a novel test that unites the Cox test with a permutation test based on restricted mean survival time. We propose a combined hypothesis test based on a permutation test of the difference in restricted mean survival time across time. The test involves the minimum of the Cox and permutation test P-values. We approximate its null distribution and correct it for correlation between the two P-values. Using extensive simulations, we assess the type 1 error and power of the combined test under several scenarios and compare with other tests. We investigate powering a trial using the combined test. The type 1 error of the combined test is close to nominal. Power under proportional hazards is slightly lower than for the Cox test. Enhanced power is available when the treatment difference shows an 'early effect', an initial separation of survival curves which diminishes over time. The power is reduced under a 'late effect', when little or no difference in survival curves is seen for an initial period and then a late separation occurs. We propose a method of powering a trial using the combined test. The 'insurance premium' offered by the combined test to safeguard power under non-PH represents about a single-digit percentage increase in sample size. The combined test increases trial power under an early treatment effect and protects power under other scenarios. Use of restricted mean survival time facilitates testing and displaying a generalized treatment effect.

TU-FG-BRB-03: Basis Vector Model Based Method for Proton Stopping Power Estimation From Experimental Dual Energy CT Data

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

Zhang, S; Politte, D; O’Sullivan, J

2016-06-15

Purpose: This work aims at reducing the uncertainty in proton stopping power (SP) estimation by a novel combination of a linear, separable basis vector model (BVM) for stopping power calculation (Med Phys 43:600) and a statistical, model-based dual-energy CT (DECT) image reconstruction algorithm (TMI 35:685). The method was applied to experimental data. Methods: BVM assumes the photon attenuation coefficients, electron densities, and mean excitation energies (I-values) of unknown materials can be approximated by a combination of the corresponding quantities of two reference materials. The DECT projection data for a phantom with 5 different known materials was collected on a Philipsmore » Brilliance scanner using two scans at 90 kVp and 140 kVp. The line integral alternating minimization (LIAM) algorithm was used to recover the two BVM coefficient images using the measured source spectra. The proton stopping powers are then estimated from the Bethe-Bloch equation using electron densities and I-values derived from the BVM coefficients. The proton stopping powers and proton ranges for the phantom materials estimated via our BVM based DECT method are compared to ICRU reference values and a post-processing DECT analysis (Yang PMB 55:1343) applied to vendorreconstructed images using the Torikoshi parametric fit model (tPFM). Results: For the phantom materials, the average stopping power estimations for 175 MeV protons derived from our method are within 1% of the ICRU reference values (except for Teflon with a 1.48% error), with an average standard deviation of 0.46% over pixels. The resultant proton ranges agree with the reference values within 2 mm. Conclusion: Our principled DECT iterative reconstruction algorithm, incorporating optimal beam hardening and scatter corrections, in conjunction with a simple linear BVM model, achieves more accurate and robust proton stopping power maps than the post-processing, nonlinear tPFM based DECT analysis applied to conventional reconstructions of low and high energy scans. Funding Support: NIH R01CA 75371; NCI grant R01 CA 149305.« less

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

NASA Astrophysics Data System (ADS)

Fourrate, K.; Loulidi, M.

2006-01-01

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

The introspective may achieve more: Enhancing existing Geoscientific models with native-language emulated structural reflection

DOE PAGES

Ji, Xinye; Shen, Chaopeng

2017-09-28

Geoscientific models manage myriad and increasingly complex data structures as trans-disciplinary models are integrated. They often incur significant redundancy with cross-cutting tasks. Reflection, the ability of a program to inspect and modify its structure and behavior at runtime, is known as a powerful tool to improve code reusability, abstraction, and separation of concerns. Reflection is rarely adopted in high-performance Geoscientific models, especially with Fortran, where it was previously deemed implausible. Practical constraints of language and legacy often limit us to feather-weight, native-language solutions. We demonstrate the usefulness of a structural-reflection-emulating, dynamically-linked metaObjects, gd. We show real-world examples including data structuremore » self-assembly, effortless save/restart and upgrade to parallel I/O, recursive actions and batch operations. We share gd and a derived module that reproduces MATLAB-like structure in Fortran and C++. We suggest that both a gd representation and a Fortran-native representation are maintained to access the data, each for separate purposes. In conclusion, embracing emulated reflection allows generically-written codes that are highly re-usable across projects.« less

The introspective may achieve more: Enhancing existing Geoscientific models with native-language emulated structural reflection

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

Ji, Xinye; Shen, Chaopeng

Geoscientific models manage myriad and increasingly complex data structures as trans-disciplinary models are integrated. They often incur significant redundancy with cross-cutting tasks. Reflection, the ability of a program to inspect and modify its structure and behavior at runtime, is known as a powerful tool to improve code reusability, abstraction, and separation of concerns. Reflection is rarely adopted in high-performance Geoscientific models, especially with Fortran, where it was previously deemed implausible. Practical constraints of language and legacy often limit us to feather-weight, native-language solutions. We demonstrate the usefulness of a structural-reflection-emulating, dynamically-linked metaObjects, gd. We show real-world examples including data structuremore » self-assembly, effortless save/restart and upgrade to parallel I/O, recursive actions and batch operations. We share gd and a derived module that reproduces MATLAB-like structure in Fortran and C++. We suggest that both a gd representation and a Fortran-native representation are maintained to access the data, each for separate purposes. In conclusion, embracing emulated reflection allows generically-written codes that are highly re-usable across projects.« less

Modelling aspects regarding the control in 13C isotope separation column

NASA Astrophysics Data System (ADS)

Boca, M. L.

2016-08-01

Carbon represents the fourth most abundant chemical element in the world, having two stable and one radioactive isotope. The 13Carbon isotopes, with a natural abundance of 1.1%, plays an important role in numerous applications, such as the study of human metabolism changes, molecular structure studies, non-invasive respiratory tests, Alzheimer tests, air pollution and global warming effects on plants [9] A manufacturing control system manages the internal logistics in a production system and determines the routings of product instances, the assignment of workers and components, the starting of the processes on not-yet-finished product instances. Manufacturing control does not control the manufacturing processes themselves, but has to cope with the consequences of the processing results (e.g. the routing of products to a repair station). In this research it was fulfilled some UML (Unified Modelling Language) diagrams for modelling the C13 Isotope Separation column, implement in STARUML program. Being a critical process and needing a good control and supervising, the critical parameters in the column, temperature and pressure was control using some PLC (Programmable logic controller) and it was made some graphic analyze for this to observe some critical situation than can affect the separation process. The main parameters that need to be control are: -The liquid nitrogen (N2) level in the condenser. -The electrical power supplied to the boiler. -The vacuum pressure.

The economics of nuclear power

NASA Astrophysics Data System (ADS)

Horst, Ronald L.

We extend economic analysis of the nuclear power industry by developing and employing three tools. They are (1) compilation and unification of operating and accounting data sets for plants and sites, (2) an abstract industry model with major economic agents and features, and (3) a model of nuclear power plant operators. We build a matched data set to combine dissimilar but mutually dependant bodies of information. We match detailed information on the activities and conditions of individual plants to slightly more aggregated financial data. Others have exploited the data separately, but we extend the sets and pool available data sets. The data reveal dramatic changes in the industry over the past thirty years. The 1980s proved unprofitable for the industry. This is evident both in the cost data and in the operator activity data. Productivity then improved dramatically while cost growth stabilized to the point of industry profitability. Relative electricity prices may be rising after nearly two decades of decline. Such demand side trends, together with supply side improvements, suggest a healthy industry. Our microeconomic model of nuclear power plant operators employs a forward-looking component to capture the information set available to decision makers and to model the decision-making process. Our model includes features often overlooked elsewhere, including electricity price equations and liability. Failure to account for changes in electricity price trends perhaps misled earlier scholars, and they attributed to other causes the effects on profits of changing price structures. The model includes potential losses resulting from catastrophic nuclear accidents. Applications include historical simulations and forecasts. Nuclear power involves risk, and accident costs are borne both by plant owners and the public. Authorities regulate the industry and balance conflicting desires for economic gain and safety. We construct an extensible model with regulators, plant operators, insurance companies, and consumers. The model possesses key attributes of the industry seldom found in combination elsewhere. We then add additional details to make the model truer to reality. The work extends and corrects existing literature on the definition, effects, and magnitudes of implicit subsidies resulting from liability limits.

40 CFR 1042.135 - Labeling.

Code of Federal Regulations, 2011 CFR

2011-07-01

... label. (e) For engines requiring ULSD, create a separate label with the statement: “ULTRA LOW SULFUR... power (in kW), and power density (in kW/L) as needed to determine the emission standards for the engine family. You may specify displacement, maximum engine power, or power density as a range consistent with...

A statistical spatial power spectrum of the Earth's lithospheric magnetic field

NASA Astrophysics Data System (ADS)

Thébault, E.; Vervelidou, F.

2015-05-01

The magnetic field of the Earth's lithosphere arises from rock magnetization contrasts that were shaped over geological times. The field can be described mathematically in spherical harmonics or with distributions of magnetization. We exploit this dual representation and assume that the lithospheric field is induced by spatially varying susceptibility values within a shell of constant thickness. By introducing a statistical assumption about the power spectrum of the susceptibility, we then derive a statistical expression for the spatial power spectrum of the crustal magnetic field for the spatial scales ranging from 60 to 2500 km. This expression depends on the mean induced magnetization, the thickness of the shell, and a power law exponent for the power spectrum of the susceptibility. We test the relevance of this form with a misfit analysis to the observational NGDC-720 lithospheric magnetic field model power spectrum. This allows us to estimate a mean global apparent induced magnetization value between 0.3 and 0.6 A m-1, a mean magnetic crustal thickness value between 23 and 30 km, and a root mean square for the field value between 190 and 205 nT at 95 per cent. These estimates are in good agreement with independent models of the crustal magnetization and of the seismic crustal thickness. We carry out the same analysis in the continental and oceanic domains separately. We complement the misfit analyses with a Kolmogorov-Smirnov goodness-of-fit test and we conclude that the observed power spectrum can be each time a sample of the statistical one.

Design and performance of a centimetre-scale shrouded wind turbine for energy harvesting

NASA Astrophysics Data System (ADS)

Howey, D. A.; Bansal, A.; Holmes, A. S.

2011-08-01

A miniature shrouded wind turbine aimed at energy harvesting for power delivery to wireless sensors in pipes and ducts is presented. The device has a rotor diameter of 2 cm, with an outer diameter of 3.2 cm, and generates electrical power by means of an axial-flux permanent magnet machine built into the shroud. Fabrication was accomplished using a combination of traditional machining, rapid prototyping, and flexible printed circuit board technology for the generator stator, with jewel bearings providing low friction and start up speed. Prototype devices can operate at air speeds down to 3 m s-1, and deliver between 80 µW and 2.5 mW of electrical power at air speeds in the range 3-7 m s-1. Experimental turbine performance curves, obtained by wind tunnel testing and corrected for bearing losses using data obtained in separate vacuum run-down tests, are compared with the predictions of an elementary blade element momentum (BEM) model. The two show reasonable agreement at low tip speed ratios. However, in experiments where a maximum could be observed, the maximum power coefficient (~9%) is marginally lower than predicted from the BEM model and occurs at a lower than predicted tip speed ratio of around 0.6.

Confirmation of quasi-static approximation in SAR evaluation for a wireless power transfer system.

PubMed

Hirata, Akimasa; Ito, Fumihiro; Laakso, Ilkka

2013-09-07

The present study discusses the applicability of the magneto-quasi-static approximation to the calculation of the specific absorption rate (SAR) in a cylindrical model for a wireless power transfer system. Resonant coils with different parameters were considered in the 10 MHz band. A two-step quasi-static method that is comprised of the method of moments and the scalar-potential finite-difference methods is applied, which can consider the effects of electric and magnetic fields on the induced SAR separately. From our computational results, the SARs obtained from our quasi-static method are found to be in good agreement with full-wave analysis for different positions of the cylindrical model relative to the wireless power transfer system, confirming the applicability of the quasi-static approximation in the 10 MHz band. The SAR induced by the external electric field is found to be marginal as compared to that induced by the magnetic field. Thus, the dosimetry for the external magnetic field, which may be marginally perturbed by the presence of biological tissue, is confirmed to be essential for SAR compliance in the 10 MHz band or lower. This confirmation also suggests that the current in the coil rather than the transferred power is essential for SAR compliance.

Removing an intersubject variance component in a general linear model improves multiway factoring of event-related spectral perturbations in group EEG studies.

PubMed

Spence, Jeffrey S; Brier, Matthew R; Hart, John; Ferree, Thomas C

2013-03-01

Linear statistical models are used very effectively to assess task-related differences in EEG power spectral analyses. Mixed models, in particular, accommodate more than one variance component in a multisubject study, where many trials of each condition of interest are measured on each subject. Generally, intra- and intersubject variances are both important to determine correct standard errors for inference on functions of model parameters, but it is often assumed that intersubject variance is the most important consideration in a group study. In this article, we show that, under common assumptions, estimates of some functions of model parameters, including estimates of task-related differences, are properly tested relative to the intrasubject variance component only. A substantial gain in statistical power can arise from the proper separation of variance components when there is more than one source of variability. We first develop this result analytically, then show how it benefits a multiway factoring of spectral, spatial, and temporal components from EEG data acquired in a group of healthy subjects performing a well-studied response inhibition task. Copyright © 2011 Wiley Periodicals, Inc.

The Applied Mathematics for Power Systems (AMPS)

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

Chertkov, Michael

2012-07-24

Increased deployment of new technologies, e.g., renewable generation and electric vehicles, is rapidly transforming electrical power networks by crossing previously distinct spatiotemporal scales and invalidating many traditional approaches for designing, analyzing, and operating power grids. This trend is expected to accelerate over the coming years, bringing the disruptive challenge of complexity, but also opportunities to deliver unprecedented efficiency and reliability. Our Applied Mathematics for Power Systems (AMPS) Center will discover, enable, and solve emerging mathematics challenges arising in power systems and, more generally, in complex engineered networks. We will develop foundational applied mathematics resulting in rigorous algorithms and simulation toolboxesmore » for modern and future engineered networks. The AMPS Center deconstruction/reconstruction approach 'deconstructs' complex networks into sub-problems within non-separable spatiotemporal scales, a missing step in 20th century modeling of engineered networks. These sub-problems are addressed within the appropriate AMPS foundational pillar - complex systems, control theory, and optimization theory - and merged or 'reconstructed' at their boundaries into more general mathematical descriptions of complex engineered networks where important new questions are formulated and attacked. These two steps, iterated multiple times, will bridge the growing chasm between the legacy power grid and its future as a complex engineered network.« less

On the Suitability of Lanthanides as Actinide Analogs

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

Szigethy, Geza; Raymond, Kenneth N.

2008-04-11

With the current level of actinide materials used in civilian power generation and the need for safe and efficient methods for the chemical separation of these species from their daughter products and for long-term storage requirements, a detailed understanding of actinide chemistry is of great importance. Due to the unique bonding properties of the f-elements, the lanthanides are commonly used as structural and chemical models for the actinides, but differences in the bonding between these 4f and 5f elements has become a question of immediate applicability to separations technology. This brief overview of actinide coordination chemistry in the Raymond groupmore » at UC Berkeley/LBNL examines the validity of using lanthanide analogs as structural models for the actinides, with particular attention paid to single crystal X-ray diffraction structures. Although lanthanides are commonly accepted as reasonable analogs for the actinides, these comparisons suggest the careful study of actinide materials independent of their lanthanide analogs to be of utmost importance to present and future efforts in nuclear industries.« less

Use of Transition Modeling to Enable the Computation of Losses for Variable-Speed Power Turbine

NASA Technical Reports Server (NTRS)

Ameri, Ali A.

2012-01-01

To investigate the penalties associated with using a variable speed power turbine (VSPT) in a rotorcraft capable of vertical takeoff and landing, various analysis tools are required. Such analysis tools must be able to model the flow accurately within the operating envelope of VSPT. For power turbines low Reynolds numbers and a wide range of the incidence angles, positive and negative, due to the variation in the shaft speed at relatively fixed corrected flows, characterize this envelope. The flow in the turbine passage is expected to be transitional and separated at high incidence. The turbulence model of Walters and Leylek was implemented in the NASA Glenn-HT code to enable a more accurate analysis of such flows. Two-dimensional heat transfer predictions of flat plate flow and two-dimensional and three-dimensional heat transfer predictions on a turbine blade were performed and reported herein. Heat transfer computations were performed because it is a good marker for transition. The final goal is to be able to compute the aerodynamic losses. Armed with the new transition model, total pressure losses for three-dimensional flow of an Energy Efficient Engine (E3) tip section cascade for a range of incidence angles were computed in anticipation of the experimental data. The results obtained form a loss bucket for the chosen blade.

Strategies to optimize lithium-ion supercapacitors achieving high-performance: Cathode configurations, lithium loadings on anode, and types of separator

NASA Astrophysics Data System (ADS)

Cao, Wanjun; Li, Yangxing; Fitch, Brian; Shih, Jonathan; Doung, Tien; Zheng, Jim

2014-12-01

The Li-ion capacitor (LIC) is composed of a lithium-doped carbon anode and an activated carbon cathode, which is a half Li-ion battery (LIB) and a half electrochemical double-layer capacitor (EDLC). LICs can achieve much more energy density than EDLC without sacrificing the high power performance advantage of capacitors over batteries. LIC pouch cells were assembled using activated carbon (AC) cathode and hard carbon (HC) + stabilized lithium metal power (SLMP®) anode. Different cathode configurations, various SLMP loadings on HC anode, and two types of separators were investigated to achieve the optimal electrochemical performance of the LIC. Firstly, the cathode binders study suggests that the PTFE binder offers improved energy and power performances for LIC in comparison to PVDF. Secondly, the mass ratio of SLMP to HC is at 1:7 to obtain the optimized electrochemical performance for LIC among all the various studied mass ratios between lithium loading amounts and active anode material. Finally, compared to the separator Celgard PP 3501, cellulose based TF40-30 is proven to be a preferred separator for LIC.

Surfactant-free microemulsion electrokinetic chromatography (SF-MEEKC) with UV and MS detection - a novel approach for the separation and ESI-MS detection of neutral compounds.

PubMed

Mohorič, Urška; Beutner, Andrea; Krickl, Sebastian; Touraud, Didier; Kunz, Werner; Matysik, Frank-Michael

2016-12-01

Microemulsion electrokinetic chromatography (MEEKC) is a powerful tool to separate neutral species based on differences in their hydrophobic and hydrophilic properties. However, as a major drawback the conventionally used SDS based microemulsions are not compatible with electrospray ionization mass spectrometry (ESI-MS). In this work, a surfactant-free microemulsion (SFME) consisting of water, ethanol, and 1-octanol is used for surfactant-free microemulsion electrokinetic chromatography (SF-MEEKC). Ammonium acetate was added to the SFME enabling electrophoretic separations. The stability of SFMEs containing ammonium acetate was investigated using small-angle X-ray scattering and dynamic light scattering. A method for the separation of a model system of hydrophobic and hydrophilic neutral vitamins, namely the vitamins B 2 and D 3 , and the cationic vitamin B 1 was developed using UV/VIS detection. The influence of the ammonium acetate concentration on the separation performance was studied in detail. The method was characterized concerning reproducibility of migration times and peak areas and concerning the linearity of the calibration data. Furthermore, SF-MEEKC was coupled to ESI-MS investigating the compatibility between SFMEs and the ESI process. The signal intensities of ESI-MS measurements of the model analytes were comparable for SFMEs and aqueous systems. Finally, the vitamin D 3 content of a drug treating vitamin D 3 deficiency was determined by SF-MEEKC coupled to ESI-MS using 25-hydroxycholecalciferol as an internal standard. Graphical abstract The concept of surfactant-free microemulsion electrokinetic chromatography coupled to electrospray ionization mass spectrometry.

Inherently Safe Fission Power System for Lunar Outposts

NASA Astrophysics Data System (ADS)

Schriener, Timothy M.; El-Genk, Mohamed S.

2013-09-01

This paper presents the Solid Core-Sectored Compact Reactor (SC-SCoRe) and power system for future lunar outposts. The power system nominally provides 38 kWe continuously for 21 years, employs static components and has no single point failures in reactor cooling or power generation. The reactor core has six sectors, each has a separate pair of primary and secondary loops with liquid NaK-56 working fluid, thermoelectric (TE) power conversion and heat-pipes radiator panels. The electromagnetic (EM) pumps in the primary and secondary loops, powered with separate TE power units, ensure operation reliability and passive decay heat removal from the reactor after shutdown. The reactor poses no radiological concerns during launch, and remains sufficiently subcritical, with the radial reflector dissembled, when submerged in wet sand and the core flooded with seawater, following a launch abort accident. After 300 years of storage below grade on the Moon, the total radioactivity in the post-operation reactor drops below 164 Ci, a low enough radioactivity for a recovery and safe handling of the reactor.

Self-Powered Neutron Detector Qualification for Absolute On-Line In-Pile Neutron Flux Measurements in BR2

NASA Astrophysics Data System (ADS)

Vermeeren, L.; Wéber, M.

2003-06-01

A set of ten Self-Powered Neutron Detectors with Co, Rh and Ag emitters has been irradiated in several channels of the BR2 research reactor at SCK•CEN aiming at a comparison of their performance as thermal neutron flux detectors under various conditions. To allow for a correct interpretation of their signals, all detector sensitivity contributions (prompt and delayed) were calculated using a dedicated Monte Carlo model. The various contributions were also measured separately; the agreement between calculated and experimental data, including data from activation dosimetry, was excellent. Detailed neutron flux profiles were obtained from the SPND data, after correction for the finite detector lengths and for the slow response of delayed SPNDs.

Read-only high accuracy volume holographic optical correlator

NASA Astrophysics Data System (ADS)

Zhao, Tian; Li, Jingming; Cao, Liangcai; He, Qingsheng; Jin, Guofan

2011-10-01

A read-only volume holographic correlator (VHC) is proposed. After the recording of all of the correlation database pages by angular multiplexing, a stand-alone read-only high accuracy VHC will be separated from the VHC recording facilities which include the high-power laser and the angular multiplexing system. The stand-alone VHC has its own low power readout laser and very compact and simple structure. Since there are two lasers that are employed for recording and readout, respectively, the optical alignment tolerance of the laser illumination on the SLM is very sensitive. The twodimensional angular tolerance is analyzed based on the theoretical model of the volume holographic correlator. The experimental demonstration of the proposed read-only VHC is introduced and discussed.

Depletion layer recombination effects on the radiation damage hardness of gallium arsenide cells

NASA Technical Reports Server (NTRS)

Garlick, G. F. J.

1985-01-01

The significant effect of junction depletion layer recombination on the efficiency of windowed GaAs cells was demonstrated. The effect becomes more pronounced as radiation damage occurs. The depletion is considered for 1 MeV electron fluences up to 10 to the 16th power e/sq m. The cell modeling separates damage in emitter and base or buffer layers using different damage coefficients is reported. The lower coefficient for the emitter predicts less loss of performance at fluences greater than 10 to the 15th power e/sq cm. A method for obtaining information on junction recombination effects as damage proceeds is described; this enables a more complete diagnosis of damage to be made.

Development and performance of pulse-width-modulated static inverter and converter modules

NASA Technical Reports Server (NTRS)

Pittman, P. F.; Gourash, F.; Birchenough, A. G.; Pittman, P. F.; Ravas, R. J.; Hall, W. G.

1971-01-01

Pulse-width-modulated inverter and converter modules are being developed for modular aerospace electrical power systems. The modules, rate 2.5 kilowatts per module and 10-minute - 150-percent overload, operate from 56 volts dc. The converter module provides two output voltages: a nominal link voltage of 200 volts dc when used with the inverter, and 150 volts dc to a load bus when used separately. The inverter module output is 400-hertz, sinusoidal, three-phase, 120/208 volts. Tests of breadboard models with standard parts and integrated circuits show rated power efficiencies of 71.4 and 85.1 percent and voltage regulation of 5 and 3.1 percent for inverter and converter modules, respectively. Sine-wave output distortion is 0.74 percent.

Performance of a Fuel-Cell-Powered, Small Electric Airplane Assessed

NASA Technical Reports Server (NTRS)

Berton, Jeffrey J.

2004-01-01

Rapidly emerging fuel-cell-power technologies may be used to launch a new revolution of electric propulsion systems for light aircraft. Future small electric airplanes using fuel cell technologies hold the promise of high reliability, low maintenance, low noise, and - with the exception of water vapor - zero emissions. An analytical feasibility and performance assessment was conducted by NASA Glenn Research Center's Airbreathing Systems Analysis Office of a fuel-cell-powered, propeller-driven, small electric airplane based on a model of the MCR-01 two-place kitplane (Dyn'Aero, Darois, France). This assessment was conducted in parallel with an ongoing effort by the Advanced Technology Products Corporation and the Foundation for Advancing Science and Technology Education. Their project - partially funded by a NASA grant - is to design, build, and fly the first manned, continuously propelled, nongliding electric airplane. In our study, an analytical performance model of a proton exchange membrane (PEM) fuel cell propulsion system was developed and applied to a notional, two-place light airplane modeled after the MCR-01 kitplane. The PEM fuel cell stack was fed pure hydrogen fuel and humidified ambient air via a small automotive centrifugal supercharger. The fuel cell performance models were based on chemical reaction analyses calibrated with published data from the fledgling U.S. automotive fuel cell industry. Electric propeller motors, rated at two shaft power levels in separate assessments, were used to directly drive a two-bladed, variable-pitch propeller. Fuel sources considered were compressed hydrogen gas and cryogenic liquid hydrogen. Both of these fuel sources provided pure, contaminant-free hydrogen for the PEM cells.

Transient birefringence effects in electromagnetically induced transparency

NASA Astrophysics Data System (ADS)

Parshkov, O. M.

2015-11-01

We report the results of numerical modelling of transient birefringence that arises as a result of electromagnetically induced transparency on degenerate quantum transitions between the states with J = 0, 1 and 2 in the presence of the Doppler broadening of spectral lines. It is shown that in the case of a linearly polarised control field, the effect of transient birefringence leads to a decay of the input circularly polarised probe pulse into separate linearly polarised pulses inside a medium. In the case of a circularly polarised control field, the effect of transient birefringence manifests itself in a decay of the input linearly polarised probe pulse into separate circularly polarised pulses. It is shown that the distance that a probe pulse has to pass in a medium before decaying into subpulses is considerably greater in the first case than in the second. The influence of the input probe pulse power and duration on the process of spatial separation into individual pulses inside a medium is studied. A qualitative analysis of the obtained results is presented.

Control over phase separation and nucleation using a laser-tweezing potential

NASA Astrophysics Data System (ADS)

Walton, Finlay; Wynne, Klaas

2018-05-01

Control over the nucleation of new phases is highly desirable but elusive. Even though there is a long history of crystallization engineering by varying physicochemical parameters, controlling which polymorph crystallizes or whether a molecule crystallizes or forms an amorphous precipitate is still a poorly understood practice. Although there are now numerous examples of control using laser-induced nucleation, the absence of physical understanding is preventing progress. Here we show that the proximity of a liquid-liquid critical point or the corresponding binodal line can be used by a laser-tweezing potential to induce concentration gradients. A simple theoretical model shows that the stored electromagnetic energy of the laser beam produces a free-energy potential that forces phase separation or triggers the nucleation of a new phase. Experiments in a liquid mixture using a low-power laser diode confirm the effect. Phase separation and nucleation using a laser-tweezing potential explains the physics behind non-photochemical laser-induced nucleation and suggests new ways of manipulating matter.

Lateral distribution of muons in IceCube cosmic ray events

NASA Astrophysics Data System (ADS)

Abbasi, R.; Abdou, Y.; Ackermann, M.; Adams, J.; Aguilar, J. A.; Ahlers, M.; Altmann, D.; Andeen, K.; Auffenberg, J.; Bai, X.; Baker, M.; Barwick, S. W.; Baum, V.; Bay, R.; Beattie, K.; Beatty, J. J.; Bechet, S.; Becker Tjus, J.; Becker, K.-H.; Bell, M.; Benabderrahmane, M. L.; BenZvi, S.; Berdermann, J.; Berghaus, P.; Berley, D.; Bernardini, E.; Bertrand, D.; Besson, D. Z.; Bindig, D.; Bissok, M.; Blaufuss, E.; Blumenthal, J.; Boersma, D. J.; Bohm, C.; Bose, D.; Böser, S.; Botner, O.; Brayeur, L.; Brown, A. M.; Bruijn, R.; Brunner, J.; Buitink, S.; Carson, M.; Casey, J.; Casier, M.; Chirkin, D.; Christy, B.; Clevermann, F.; Cohen, S.; Cowen, D. F.; Cruz Silva, A. H.; Danninger, M.; Daughhetee, J.; Davis, J. C.; De Clercq, C.; Descamps, F.; Desiati, P.; de Vries-Uiterweerd, G.; DeYoung, T.; Díaz-Vélez, J. C.; Dreyer, J.; Dumm, J. P.; Dunkman, M.; Eagan, R.; Eisch, J.; Ellsworth, R. W.; Engdegård, O.; Euler, S.; Evenson, P. A.; Fadiran, O.; Fazely, A. R.; Fedynitch, A.; Feintzeig, J.; Feusels, T.; Filimonov, K.; Finley, C.; Fischer-Wasels, T.; Flis, S.; Franckowiak, A.; Franke, R.; Frantzen, K.; Fuchs, T.; Gaisser, T. K.; Gallagher, J.; Gerhardt, L.; Gladstone, L.; Glüsenkamp, T.; Goldschmidt, A.; Goodman, J. A.; Góra, D.; Grant, D.; Groß, A.; Grullon, S.; Gurtner, M.; Ha, C.; Haj Ismail, A.; Hallgren, A.; Halzen, F.; Hanson, K.; Heereman, D.; Heimann, P.; Heinen, D.; Helbing, K.; Hellauer, R.; Hickford, S.; Hill, G. C.; Hoffman, K. D.; Hoffmann, R.; Homeier, A.; Hoshina, K.; Huelsnitz, W.; Hulth, P. O.; Hultqvist, K.; Hussain, S.; Ishihara, A.; Jacobi, E.; Jacobsen, J.; Japaridze, G. S.; Jlelati, O.; Kappes, A.; Karg, T.; Karle, A.; Kiryluk, J.; Kislat, F.; Kläs, J.; Klein, S. R.; Köhne, J.-H.; Kohnen, G.; Kolanoski, H.; Köpke, L.; Kopper, C.; Kopper, S.; Koskinen, D. J.; Kowalski, M.; Krasberg, M.; Kroll, G.; Kunnen, J.; Kurahashi, N.; Kuwabara, T.; Labare, M.; Laihem, K.; Landsman, H.; Larson, M. J.; Lauer, R.; Lesiak-Bzdak, M.; Lünemann, J.; Madsen, J.; Maruyama, R.; Mase, K.; Matis, H. S.; McNally, F.; Meagher, K.; Merck, M.; Mészáros, P.; Meures, T.; Miarecki, S.; Middell, E.; Milke, N.; Miller, J.; Mohrmann, L.; Montaruli, T.; Morse, R.; Movit, S. M.; Nahnhauer, R.; Naumann, U.; Nowicki, S. C.; Nygren, D. R.; Obertacke, A.; Odrowski, S.; Olivas, A.; Olivo, M.; O'Murchadha, A.; Panknin, S.; Paul, L.; Pepper, J. A.; Pérez de los Heros, C.; Pieloth, D.; Pirk, N.; Posselt, J.; Price, P. B.; Przybylski, G. T.; Rädel, L.; Rawlins, K.; Redl, P.; Resconi, E.; Rhode, W.; Ribordy, M.; Richman, M.; Riedel, B.; Rodrigues, J. P.; Rothmaier, F.; Rott, C.; Ruhe, T.; Ruzybayev, B.; Ryckbosch, D.; Saba, S. M.; Salameh, T.; Sander, H.-G.; Santander, M.; Sarkar, S.; Schatto, K.; Scheel, M.; Scheriau, F.; Schmidt, T.; Schmitz, M.; Schoenen, S.; Schöneberg, S.; Schönherr, L.; Schönwald, A.; Schukraft, A.; Schulte, L.; Schulz, O.; Seckel, D.; Seo, S. H.; Sestayo, Y.; Seunarine, S.; Smith, M. W. E.; Soiron, M.; Soldin, D.; Spiczak, G. M.; Spiering, C.; Stamatikos, M.; Stanev, T.; Stasik, A.; Stezelberger, T.; Stokstad, R. G.; Stößl, A.; Strahler, E. A.; Ström, R.; Sullivan, G. W.; Taavola, H.; Taboada, I.; Tamburro, A.; Ter-Antonyan, S.; Tilav, S.; Toale, P. A.; Toscano, S.; Usner, M.; van der Drift, D.; van Eijndhoven, N.; Van Overloop, A.; van Santen, J.; Vehring, M.; Voge, M.; Walck, C.; Waldenmaier, T.; Wallraff, M.; Walter, M.; Wasserman, R.; Weaver, Ch.; Wendt, C.; Westerhoff, S.; Whitehorn, N.; Wiebe, K.; Wiebusch, C. H.; Williams, D. R.; Wissing, H.; Wolf, M.; Wood, T. R.; Woschnagg, K.; Xu, C.; Xu, D. L.; Xu, X. W.; Yanez, J. P.; Yodh, G.; Yoshida, S.; Zarzhitsky, P.; Ziemann, J.; Zilles, A.; Zoll, M.

2013-01-01

In cosmic ray air showers, the muon lateral separation from the center of the shower is a measure of the transverse momentum that the muon parent acquired in the cosmic ray interaction. IceCube has observed cosmic ray interactions that produce muons laterally separated by up to 400 m from the shower core, a factor of 6 larger distance than previous measurements. These muons originate in high pT (>2GeV/c) interactions from the incident cosmic ray, or high-energy secondary interactions. The separation distribution shows a transition to a power law at large values, indicating the presence of a hard pT component that can be described by perturbative quantum chromodynamics. However, the rates and the zenith angle distributions of these events are not well reproduced with the cosmic ray models tested here, even those that include charm interactions. This discrepancy may be explained by a larger fraction of kaons and charmed particles than is currently incorporated in the simulations.

Possible application of laser isotope separation

NASA Technical Reports Server (NTRS)

Delionback, L. M.

1975-01-01

The laser isotope separation process is described and its special economic features discussed. These features are its low cost electric power operation, capital investment costs, and the costs of process materials.

A polyhedral study of production ramping

DOE PAGES

Damci-Kurt, Pelin; Kucukyavuz, Simge; Rajan, Deepak; ...

2015-06-12

Here, we give strong formulations of ramping constraints—used to model the maximum change in production level for a generator or machine from one time period to the next—and production limits. For the two-period case, we give a complete description of the convex hull of the feasible solutions. The two-period inequalities can be readily used to strengthen ramping formulations without the need for separation. For the general case, we define exponential classes of multi-period variable upper bound and multi-period ramping inequalities, and give conditions under which these inequalities define facets of ramping polyhedra. Finally, we present exact polynomial separation algorithms formore » the inequalities and report computational experiments on using them in a branch-and-cut algorithm to solve unit commitment problems in power generation.« less

Cooperation Helps Power Saving

DTIC Science & Technology

2009-04-07

the destination node hears the poll, the link between the two nodes is activated. In the original STEM, two radios working on two separate channels... hears the poll, the link between the two nodes is activated. In the original STEM, two radios working on two separate chan- nels are used: one radio is...Computer and Communications Societies. Proceedings. IEEE, vol. 3, pp. 1548–1557 vol.3, 2001. [2] R . Kravets and P. Krishnan, “Application-driven power

Disk MHD generator study

NASA Technical Reports Server (NTRS)

Retallick, F. D.

1980-01-01

Directly-fired, separately-fired, and oxygen-augmented MHD power plants incorporating a disk geometry for the MHD generator were studied. The base parameters defined for four near-optimum-performance MHD steam power systems of various types are presented. The finally selected systems consisted of (1) two directly fired cases, one at 1920 K (2996F) preheat and the other at 1650 K (2500 F) preheat, (2) a separately-fired case where the air is preheated to the same level as the higher temperature directly-fired cases, and (3) an oxygen augmented case with the same generator inlet temperature of 2839 (4650F) as the high temperature directly-fired and separately-fired cases. Supersonic Mach numbers at the generator inlet, gas inlet swirl, and constant Hall field operation were specified based on disk generator optimization. System pressures were based on optimization of MHD net power. Supercritical reheat stream plants were used in all cases. Open and closed cycle component costs are summarized and compared.

Hydrodynamical models of cometary H II regions

NASA Astrophysics Data System (ADS)

Steggles, H. G.; Hoare, M. G.; Pittard, J. M.

2017-04-01

We have modelled the evolution of cometary H II regions produced by zero-age main-sequence stars of O and B spectral types, which are driving strong winds and are born off-centre from spherically symmetric cores with power-law (α = 2) density slopes. A model parameter grid was produced that spans stellar mass, age and core density. Exploring this parameter space, we investigated limb-brightening, a feature commonly seen in cometary H II regions. We found that stars with mass M⋆ ≥ 12 M⊙ produce this feature. Our models have a cavity bounded by a contact discontinuity separating hot shocked wind and ionized ambient gas that is similar in size to the surrounding H II region. Because of early pressure confinement, we did not see shocks outside of the contact discontinuity for stars with M⋆ ≤ 40 M⊙, but the cavities were found to continue to grow. The cavity size in each model plateaus as the H II region stagnates. The spectral energy distributions of our models are similar to those from identical stars evolving in uniform density fields. The turn-over frequency is slightly lower in our power-law models as a result of a higher proportion of low-density gas covered by the H II regions.

Separation of arteries and veins in the cerebral cortex using physiological oscillations by optical imaging of intrinsic signal

NASA Astrophysics Data System (ADS)

Hu, Dewen; Wang, Yucheng; Liu, Yadong; Li, Ming; Liu, Fayi

2010-05-01

An automated method is presented for artery-vein separation in cerebral cortical images recorded with optical imaging of the intrinsic signal. The vessel-type separation method is based on the fact that the spectral distribution of intrinsic physiological oscillations varies from arterial regions to venous regions. In arterial regions, the spectral power is higher in the heartbeat frequency (HF), whereas in venous regions, the spectral power is higher in the respiration frequency (RF). The separation method was begun by extracting the vascular network and its centerline. Then the spectra of the optical intrinsic signals were estimated by the multitaper method. A standard F-test was performed on each discrete frequency point to test the statistical significance at the given level. Four periodic physiological oscillations were examined: HF, RF, and two other eigenfrequencies termed F1 and F2. The separation of arteries and veins was implemented with the fuzzy c-means clustering method and the region-growing approach by utilizing the spectral amplitudes and power-ratio values of the four eigenfrequencies on the vasculature. Subsequently, independent spectral distributions in the arteries, veins, and capillary bed were estimated for comparison, which showed that the spectral distributions of the intrinsic signals were very distinct between the arterial and venous regions.

Separation of arteries and veins in the cerebral cortex using physiological oscillations by optical imaging of intrinsic signal.

PubMed

Hu, Dewen; Wang, Yucheng; Liu, Yadong; Li, Ming; Liu, Fayi

2010-01-01

An automated method is presented for artery-vein separation in cerebral cortical images recorded with optical imaging of the intrinsic signal. The vessel-type separation method is based on the fact that the spectral distribution of intrinsic physiological oscillations varies from arterial regions to venous regions. In arterial regions, the spectral power is higher in the heartbeat frequency (HF), whereas in venous regions, the spectral power is higher in the respiration frequency (RF). The separation method was begun by extracting the vascular network and its centerline. Then the spectra of the optical intrinsic signals were estimated by the multitaper method. A standard F-test was performed on each discrete frequency point to test the statistical significance at the given level. Four periodic physiological oscillations were examined: HF, RF, and two other eigenfrequencies termed F1 and F2. The separation of arteries and veins was implemented with the fuzzy c-means clustering method and the region-growing approach by utilizing the spectral amplitudes and power-ratio values of the four eigenfrequencies on the vasculature. Subsequently, independent spectral distributions in the arteries, veins, and capillary bed were estimated for comparison, which showed that the spectral distributions of the intrinsic signals were very distinct between the arterial and venous regions.

Certainty Equivalence M-MRAC for Systems with Unmatched Uncertainties

NASA Technical Reports Server (NTRS)

Stepanyan, Vahram; Krishnakumar, Kalmanje

2012-01-01

The paper presents a certainty equivalence state feedback indirect adaptive control design method for the systems of any relative degree with unmatched uncertainties. The approach is based on the parameter identification (estimation) model, which is completely separated from the control design and is capable of producing parameter estimates as fast as the computing power allows without generating high frequency oscillations. It is shown that the system's input and output tracking errors can be systematically decreased by the proper choice of the design parameters.

Accelerated High-Resolution Differential Ion Mobility Separations Using Hydrogen

PubMed Central

Shvartsburg, Alexandre A.; Smith, Richard D.

2011-01-01

The resolving power of differential ion mobility spectrometry (FAIMS) was dramatically increased recently by carrier gases comprising up to 75% He or various vapors, enabling many new applications. However, the need for resolution of complex mixtures is virtually open-ended and many topical analyses demand yet finer separations. Also, the resolving power gains are often at the expense of speed, in particular making high-resolution FAIMS incompatible with online liquid-phase separations. Here, we report FAIMS employing hydrogen, specifically in mixtures with N2 containing up to 90% H2. Such compositions raise the mobilities of all ions and thus the resolving power beyond that previously feasible, while avoiding the electrical breakdown inevitable in He-rich mixtures. The increases in resolving power and ensuing peak resolution are especially significant at H2 fractions above ~50%. Higher resolution can be exchanged for acceleration of the analyses by up to ~4 times, at least. For more mobile species such as multiply-charged peptides, this exchange is presently forced by the constraints of existing FAIMS devices, but future designs optimized for H2 should consistently improve resolution for all analytes. PMID:22074292

Proceedings of the 21st DOE/NRC Nuclear Air Cleaning Conference; Sessions 1--8

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

First, M.W.

1991-02-01

Separate abstracts have been prepared for the papers presented at the meeting on nuclear facility air cleaning technology in the following specific areas of interest: air cleaning technologies for the management and disposal of radioactive wastes; Canadian waste management program; radiological health effects models for nuclear power plant accident consequence analysis; filter testing; US standard codes on nuclear air and gas treatment; European community nuclear codes and standards; chemical processing off-gas cleaning; incineration and vitrification; adsorbents; nuclear codes and standards; mathematical modeling techniques; filter technology; safety; containment system venting; and nuclear air cleaning programs around the world. (MB)

Scaling behavior of nonisothermal phase separation.

PubMed

Rüllmann, Max; Alig, Ingo

2004-04-22

The phase separation process in a critical mixture of polydimethylsiloxane and polyethylmethylsiloxane (PDMS/PEMS, a system with an upper critical solution temperature) was investigated by time-resolved light scattering during continuous quenches from the one-phase into the two-phase region. Continuous quenches were realized by cooling ramps with different cooling rates kappa. Phase separation kinetics is studied by means of the temporal evolution of the scattering vector qm and the intensity Im at the scattering peak. The curves qm(t) for different cooling rates can be shifted onto a single mastercurve. The curves Im(t) show similar behavior. As shift factors, a characteristic length Lc and a characteristic time tc are introduced. Both characteristic quantities depend on the cooling rate through power laws: Lc approximately kappa(-delta) and tc approximately kappa(-rho). Scaling behavior in isothermal critical demixing is well known. There the temporal evolutions of qm and Im for different quench depths DeltaT can be scaled with the correlation length xi and the interdiffusion coefficient D, both depending on DeltaT through critical power laws. We show in this paper that the cooling rate scaling in nonisothermal demixing is a consequence of the quench depth scaling in the isothermal case. The exponents delta and rho are related to the critical exponents nu and nu* of xi and D, respectively. The structure growth during nonisothermal demixing can be described with a semiempirical model based on the hydrodynamic coarsening mechanism well known in the isothermal case. In very late stages of nonisothermal phase separation a secondary scattering maximum appears. This is due to secondary demixing. We explain the onset of secondary demixing by a competition between interdiffusion and coarsening. (c) 2004 American Institute of Physics

Seismoelectric data processing for surface surveys of shallow targets

USGS Publications Warehouse

Haines, S.S.; Guitton, A.; Biondi, B.

2007-01-01

The utility of the seismoelectric method relies on the development of methods to extract the signal of interest from background and source-generated coherent noise that may be several orders-of-magnitude stronger. We compare data processing approaches to develop a sequence of preprocessing and signal/noise separation and to quantify the noise level from which we can extract signal events. Our preferred sequence begins with the removal of power line harmonic noise and the use of frequency filters to minimize random and source-generated noise. Mapping to the linear Radon domain with an inverse process incorporating a sparseness constraint provides good separation of signal from noise, though it is ineffective on noise that shows the same dip as the signal. Similarly, the seismoelectric signal and noise do not separate cleanly in the Fourier domain, so f-k filtering can not remove all of the source-generated noise and it also disrupts signal amplitude patterns. We find that prediction-error filters provide the most effective method to separate signal and noise, while also preserving amplitude information, assuming that adequate pattern models can be determined for the signal and noise. These Radon-domain and prediction-error-filter methods successfully separate signal from <33 dB stronger noise in our test data. ?? 2007 Society of Exploration Geophysicists.

Structure Optimization of a Grain Impact Piezoelectric Sensor and Its Application for Monitoring Separation Losses on Tangential-Axial Combine Harvesters

PubMed Central

Liang, Zhenwei; Li, Yaoming; Zhao, Zhan; Xu, Lizhang

2015-01-01

Grain separation losses is a key parameter to weigh the performance of combine harvesters, and also a dominant factor for automatically adjusting their major working parameters. The traditional separation losses monitoring method mainly rely on manual efforts, which require a high labor intensity. With recent advancements in sensor technology, electronics and computational processing power, this paper presents an indirect method for monitoring grain separation losses in tangential-axial combine harvesters in real-time. Firstly, we developed a mathematical monitoring model based on detailed comparative data analysis of different feeding quantities. Then, we developed a grain impact piezoelectric sensor utilizing a YT-5 piezoelectric ceramic as the sensing element, and a signal process circuit designed according to differences in voltage amplitude and rise time of collision signals. To improve the sensor performance, theoretical analysis was performed from a structural vibration point of view, and the optimal sensor structural has been selected. Grain collide experiments have shown that the sensor performance was greatly improved. Finally, we installed the sensor on a tangential-longitudinal axial combine harvester, and grain separation losses monitoring experiments were carried out in North China, which results have shown that the monitoring method was feasible, and the biggest measurement relative error was 4.63% when harvesting rice. PMID:25594592

Structure optimization of a grain impact piezoelectric sensor and its application for monitoring separation losses on tangential-axial combine harvesters.

PubMed

Liang, Zhenwei; Li, Yaoming; Zhao, Zhan; Xu, Lizhang

2015-01-14

Grain separation losses is a key parameter to weigh the performance of combine harvesters, and also a dominant factor for automatically adjusting their major working parameters. The traditional separation losses monitoring method mainly rely on manual efforts, which require a high labor intensity. With recent advancements in sensor technology, electronics and computational processing power, this paper presents an indirect method for monitoring grain separation losses in tangential-axial combine harvesters in real-time. Firstly, we developed a mathematical monitoring model based on detailed comparative data analysis of different feeding quantities. Then, we developed a grain impact piezoelectric sensor utilizing a YT-5 piezoelectric ceramic as the sensing element, and a signal process circuit designed according to differences in voltage amplitude and rise time of collision signals. To improve the sensor performance, theoretical analysis was performed from a structural vibration point of view, and the optimal sensor structural has been selected. Grain collide experiments have shown that the sensor performance was greatly improved. Finally, we installed the sensor on a tangential-longitudinal axial combine harvester, and grain separation losses monitoring experiments were carried out in North China, which results have shown that the monitoring method was feasible, and the biggest measurement relative error was 4.63% when harvesting rice.

Power: Constitutional Update. Bar/School Partnership Programs Series.

ERIC Educational Resources Information Center

American Bar Association, Chicago, IL. Special Committee on Youth Education for Citizenship.

The fourth in a special series of handbooks dealing with constitutional themes, this document looks at power in the context of the U.S. Constitution. "The Constitution's Prescription for Freedom" (L. Peach) examines the separation of powers provided for in the Constitution. "The Concept of Power" (C. Roach) is a series of…

Nuclear Power: The Market Test. Worldwatch Paper 57.

ERIC Educational Resources Information Center

Flavin, Christopher

Nuclear power was considered vital to humanity's future until just a short time ago. Since the late seventies, economic viability has joined a list of such issues as waste disposal and radiation hazards which call into question the future of nuclear power. This document discusses (in separate sections): (1) the selling of nuclear power, including…

Considering lesbian identity from a social-psychological perspective: two different models of "being a lesbian".

PubMed

Tate, Charlotte Chuck

2012-01-01

One long-standing project within lesbian studies has been to develop a satisfactory working definition of "lesbian." This article proposes two new models of a definition using principles of social psychology. Each model (a) utilizes the premise that gender lacks a categorical essence and (b) separates behavioral adherence to cultural stereotypes of femininity and masculinity from one's gender self-categorization. From these premises, I generate and critique two internally coherent models of lesbian identity that are inclusive (to different degrees) of various gender identities. For each model, the potential inclusion of trans men, trans women, genderqueers, and lesbian-identified cisgender men is evaluated. The explanatory power of these models is twofold. One, the models can serve as theoretical perspectives for scholars who study the intersection of gender and sexual identity. Two, the models can also characterize the everyday experience of people who have tacit working definitions of lesbian identity.

76 FR 9349 - Jim Woodruff Project

Federal Register 2010, 2011, 2012, 2013, 2014

2011-02-17

... month. Southeastern would compute its purchased power obligation for each delivery point monthly... rates to include a pass-through of purchased power expenses. The capacity and energy charges to preference customers can be reduced because purchased power expenses will be recovered in a separate, pass...

Wellhead power production with a rotary separator turbine (RP 1196)

NASA Astrophysics Data System (ADS)

Cerini, D. J.; Record, J.

1982-12-01

A rotary-separator turbine was built with full flow capacity for a 500 F downhole temperature with a 850,000 lbm/hr production rate. The test system and results obtained in field tests are described. The preliminary design of a 10-megawatt wellhead power plant for the Roosevelt type resource is described. This system shows a specific power of .0013 kW hr per lbm, which is 20 percent greater than an optimized wellhead single stage flash plant. This is 26 percent greater than a central plant of 20 to 50 MW capacity when consideration is given to steam-gathering system pressure drop between the wells and central plant.

Collective dynamics of 'small-world' networks.

PubMed

Watts, D J; Strogatz, S H

1998-06-04

Networks of coupled dynamical systems have been used to model biological oscillators, Josephson junction arrays, excitable media, neural networks, spatial games, genetic control networks and many other self-organizing systems. Ordinarily, the connection topology is assumed to be either completely regular or completely random. But many biological, technological and social networks lie somewhere between these two extremes. Here we explore simple models of networks that can be tuned through this middle ground: regular networks 'rewired' to introduce increasing amounts of disorder. We find that these systems can be highly clustered, like regular lattices, yet have small characteristic path lengths, like random graphs. We call them 'small-world' networks, by analogy with the small-world phenomenon (popularly known as six degrees of separation. The neural network of the worm Caenorhabditis elegans, the power grid of the western United States, and the collaboration graph of film actors are shown to be small-world networks. Models of dynamical systems with small-world coupling display enhanced signal-propagation speed, computational power, and synchronizability. In particular, infectious diseases spread more easily in small-world networks than in regular lattices.

Contrails and their impact on shortwave radiation and photovoltaic power production - a regional model study

NASA Astrophysics Data System (ADS)

Gruber, Simon; Unterstrasser, Simon; Bechtold, Jan; Vogel, Heike; Jung, Martin; Pak, Henry; Vogel, Bernhard

2018-05-01

A high-resolution regional-scale numerical model was extended by a parameterization that allows for both the generation and the life cycle of contrails and contrail cirrus to be calculated. The life cycle of contrails and contrail cirrus is described by a two-moment cloud microphysical scheme that was extended by a separate contrail ice class for a better representation of the high concentration of small ice crystals that occur in contrails. The basic input data set contains the spatially and temporally highly resolved flight trajectories over Central Europe derived from real-time data. The parameterization provides aircraft-dependent source terms for contrail ice mass and number. A case study was performed to investigate the influence of contrails and contrail cirrus on the shortwave radiative fluxes at the earth's surface. Accounting for contrails produced by aircraft enabled the model to simulate high clouds that were otherwise missing on this day. The effect of these extra clouds was to reduce the incoming shortwave radiation at the surface as well as the production of photovoltaic power by up to 10 %.

Preliminary Results Obtained from Flight Test of a 1/7-Scale Rocket-Powered Model of the Grumman XF10F Airplane Configuration in the Swept-Wing Condition, TED No. NACA DE 354

NASA Technical Reports Server (NTRS)

Gardner, William N.

1951-01-01

A flight investigation of a 1/7-scale rocket-powered model of the XF10F Grumman XFl0F airplane in the swept-wing configuration has been made. The purpose of this test was to determine the static longitudinal stability, damping in pitch, and longitudinal control effectiveness of the airplane with the center of gravity at 20 percent of the wing mean aerodynamic chord. Only a small amount of data was obtained from the test because, immediately after booster separation at a Mach number of 0.88, the configuration was directionally unstable and diverged in sideslip. Simultaneous with the sideslip divergence, the model became longitudinally unstable at 3 degree angle of attack and -6 degree sideslip and diverged in pitch to a high angle of attack. During the pitch-up the free-floating horizontal tail became unstable at 5 degree angle of attack and the tail drifted against its positive deflection limit.

Novel Application of Carbonate Fuel Cell for Capturing Carbon Dioxide from Flue Gas Streams

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

Jolly, Stephen; Ghezel-Ayagh, Hossein; Willman, Carl

To address concerns about climate change resulting from emission of CO2 by coal-fueled power plants, FuelCell Energy, Inc. has developed the Combined Electric Power and Carbon-dioxide Separation (CEPACS) system concept. The CEPACS system utilizes Electrochemical Membrane (ECM) technology derived from the Company’s Direct FuelCell® products. The system separates the CO2 from the flue gas of other plants and produces electric power using a supplementary fuel. FCE is currently evaluating the use of ECM to cost effectively separate CO2 from the flue gas of Pulverized Coal (PC) power plants under a U.S. Department of Energy contract. The overarching objective of themore » project is to verify that the ECM can achieve at least 90% CO2 capture from the flue gas with no more than 35% increase in the cost of electricity. The project activities include: 1) laboratory scale operational and performance tests of a membrane assembly, 2) performance tests of the membrane to evaluate the effects of impurities present in the coal plant flue gas, in collaboration with Pacific Northwest National Laboratory, 3) techno-economic analysis for an ECM-based CO2 capture system applied to a 550 MW existing PC plant, in partnership with URS Corporation, and 4) bench scale (11.7 m2 area) testing of an ECM-based CO2 separation and purification system.« less

Turbulence effect on crossflow around a circular cylinder at subcritical Reynolds numbers

NASA Technical Reports Server (NTRS)

Sadeh, W. Z.; Saharon, D. B.

1982-01-01

An investigation of the effect of freestream turbulence on the flow around a smooth circular cylinder at subcritical Reynolds numbers from 5.2 x 10 to the 4th power to 2.09 x 10 to the 5th power was conducted. Measurements show that the interaction of incident turbulence with the initial laminar boundary layer: (1) modifies the characteristics of the mean surface pressure distribution; (2) induces an aft shift in the separation point ranging from 5 to 50 beyond the laminar separation angle of 80 degrees; and, (3) reduces the mean drag coefficient to values between 97 and 46% of its nearly constant laminar counterpart. The extent of these changes depends on the particular Reynolds number background turbulence combination. These results demonstrate that a boundary-layer flow similar to that found in critical, supercritical and/or transcritical flow regimes is induced by turbulence at subcritical Reynolds numbers and, hence, the effect of turbulence is equivalent to an effective increase in the Reynolds number. The change in the nature and properties of the boundary layer in the subcritical regime, consequent upon the penetration of turbulence into it, is in agreement with the model proposed by the vorticity-amplification theory.

The Angular Power Spectrum of BATSE 3B Gamma-Ray Bursts

NASA Technical Reports Server (NTRS)

Tegmark, Max; Hartmann, Dieter H.; Briggs, Michael S.; Meegan, Charles A.

1996-01-01

We compute the angular power spectrum C(sub l) from the BATSE 3B catalog of 1122 gamma-ray bursts and find no evidence for clustering on any scale. These constraints bridge the entire range from small scales (which probe source clustering and burst repetition) to the largest scales (which constrain possible anisotropics from the Galactic halo or from nearby cosmological large-scale structures). We develop an analysis technique that takes the angular position errors into account. For specific clustering or repetition models, strong upper limits can be obtained down to scales l approx. equal to 30, corresponding to a couple of degrees on the sky. The minimum-variance burst weighting that we employ is visualized graphically as an all-sky map in which each burst is smeared out by an amount corresponding to its position uncertainty. We also present separate bandpass-filtered sky maps for the quadrupole term and for the multipole ranges l = 3-10 and l = 11-30, so that the fluctuations on different angular scales can be inspected separately for visual features such as localized 'hot spots' or structures aligned with the Galactic plane. These filtered maps reveal no apparent deviations from isotropy.

Two- and three-dimensional natural and mixed convection simulation using modular zonal models

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

Wurtz, E.; Nataf, J.M.; Winkelmann, F.

We demonstrate the use of the zonal model approach, which is a simplified method for calculating natural and mixed convection in rooms. Zonal models use a coarse grid and use balance equations, state equations, hydrostatic pressure drop equations and power law equations of the form {ital m} = {ital C}{Delta}{sup {ital n}}. The advantage of the zonal approach and its modular implementation are discussed. The zonal model resolution of nonlinear equation systems is demonstrated for three cases: a 2-D room, a 3-D room and a pair of 3-D rooms separated by a partition with an opening. A sensitivity analysis withmore » respect to physical parameters and grid coarseness is presented. Results are compared to computational fluid dynamics (CFD) calculations and experimental data.« less

Non-minimally coupled condensate cosmologies: a phase space analysis

NASA Astrophysics Data System (ADS)

Carloni, Sante; Vignolo, Stefano; Cianci, Roberto

2014-09-01

We present an analysis of the phase space of cosmological models based on a non-minimal coupling between the geometry and a fermionic condensate. We observe that the strong constraint coming from the Dirac equations allows a detailed design of the cosmology of these models, and at the same time guarantees an evolution towards a state indistinguishable from general relativistic cosmological models. In this light, we show in detail how the use of some specific potentials can naturally reproduce a phase of accelerated expansion. In particular, we find for the first time that an exponential potential is able to induce two de Sitter phases separated by a power law expansion, which could be an interesting model for the unification of an inflationary phase and a dark energy era.

Redshift-space distortions with the halo occupation distribution - II. Analytic model

NASA Astrophysics Data System (ADS)

Tinker, Jeremy L.

2007-01-01

We present an analytic model for the galaxy two-point correlation function in redshift space. The cosmological parameters of the model are the matter density Ωm, power spectrum normalization σ8, and velocity bias of galaxies αv, circumventing the linear theory distortion parameter β and eliminating nuisance parameters for non-linearities. The model is constructed within the framework of the halo occupation distribution (HOD), which quantifies galaxy bias on linear and non-linear scales. We model one-halo pairwise velocities by assuming that satellite galaxy velocities follow a Gaussian distribution with dispersion proportional to the virial dispersion of the host halo. Two-halo velocity statistics are a combination of virial motions and host halo motions. The velocity distribution function (DF) of halo pairs is a complex function with skewness and kurtosis that vary substantially with scale. Using a series of collisionless N-body simulations, we demonstrate that the shape of the velocity DF is determined primarily by the distribution of local densities around a halo pair, and at fixed density the velocity DF is close to Gaussian and nearly independent of halo mass. We calibrate a model for the conditional probability function of densities around halo pairs on these simulations. With this model, the full shape of the halo velocity DF can be accurately calculated as a function of halo mass, radial separation, angle and cosmology. The HOD approach to redshift-space distortions utilizes clustering data from linear to non-linear scales to break the standard degeneracies inherent in previous models of redshift-space clustering. The parameters of the occupation function are well constrained by real-space clustering alone, separating constraints on bias and cosmology. We demonstrate the ability of the model to separately constrain Ωm,σ8 and αv in models that are constructed to have the same value of β at large scales as well as the same finger-of-god distortions at small scales.

Isobar Separation in a Multiple-Reflection Time-of-Flight Mass Spectrometer by Mass-Selective Re-Trapping.

PubMed

Dickel, Timo; Plaß, Wolfgang R; Lippert, Wayne; Lang, Johannes; Yavor, Mikhail I; Geissel, Hans; Scheidenberger, Christoph

2017-06-01

A novel method for (ultra-)high-resolution spatial mass separation in time-of-flight mass spectrometers is presented. Ions are injected into a time-of-flight analyzer from a radio frequency (rf) trap, dispersed in time-of-flight according to their mass-to-charge ratios and then re-trapped dynamically in the same rf trap. This re-trapping technique is highly mass-selective and after sufficiently long flight times can provide even isobaric separation. A theoretical treatment of the method is presented and the conditions for optimum performance of the method are derived. The method has been implemented in a multiple-reflection time-of-flight mass spectrometer and mass separation powers (FWHM) in excess of 70,000, and re-trapping efficiencies of up to 35% have been obtained for the protonated molecular ion of caffeine. The isobars glutamine and lysine (relative mass difference of 1/4000) have been separated after a flight time of 0.2 ms only. Higher mass separation powers can be achieved using longer flight times. The method will have important applications, including isobar separation in nuclear physics and (ultra-)high-resolution precursor ion selection in multiple-stage tandem mass spectrometry. Graphical Abstract ᅟ.

Isobar Separation in a Multiple-Reflection Time-of-Flight Mass Spectrometer by Mass-Selective Re-Trapping

NASA Astrophysics Data System (ADS)

Dickel, Timo; Plaß, Wolfgang R.; Lippert, Wayne; Lang, Johannes; Yavor, Mikhail I.; Geissel, Hans; Scheidenberger, Christoph

2017-06-01

A novel method for (ultra-)high-resolution spatial mass separation in time-of-flight mass spectrometers is presented. Ions are injected into a time-of-flight analyzer from a radio frequency (rf) trap, dispersed in time-of-flight according to their mass-to-charge ratios and then re-trapped dynamically in the same rf trap. This re-trapping technique is highly mass-selective and after sufficiently long flight times can provide even isobaric separation. A theoretical treatment of the method is presented and the conditions for optimum performance of the method are derived. The method has been implemented in a multiple-reflection time-of-flight mass spectrometer and mass separation powers (FWHM) in excess of 70,000, and re-trapping efficiencies of up to 35% have been obtained for the protonated molecular ion of caffeine. The isobars glutamine and lysine (relative mass difference of 1/4000) have been separated after a flight time of 0.2 ms only. Higher mass separation powers can be achieved using longer flight times. The method will have important applications, including isobar separation in nuclear physics and (ultra-)high-resolution precursor ion selection in multiple-stage tandem mass spectrometry. [Figure not available: see fulltext.

Phase boundaries of power-law Anderson and Kondo models: A poor man's scaling study

NASA Astrophysics Data System (ADS)

Cheng, Mengxing; Chowdhury, Tathagata; Mohammed, Aaron; Ingersent, Kevin

2017-07-01

We use the poor man's scaling approach to study the phase boundaries of a pair of quantum impurity models featuring a power-law density of states ρ (ɛ ) ∝|ɛ| r , either vanishing (for r >0 ) or diverging (for r <0 ) at the Fermi energy ɛ =0 , that gives rise to quantum phase transitions between local-moment and Kondo-screened phases. For the Anderson model with a pseudogap (i.e., r >0 ), we find the phase boundary for (a) 0 1 , where the phases are separated by first-order quantum phase transitions that are accessible only for broken p-h symmetry. For the p-h-symmetric Kondo model with easy-axis or easy-plane anisotropy of the impurity-band spin exchange, the phase boundary and scaling trajectories are obtained for both r >0 and r <0 . Throughout the regime of weak-to-moderate impurity-band coupling in which poor man's scaling is expected to be valid, the approach predicts phase boundaries in excellent qualitative and good quantitative agreement with the nonperturbative numerical renormalization group, while also establishing the functional relations between model parameters along these boundaries.

Design and construction of an airfoil with controlled flap

NASA Astrophysics Data System (ADS)

Amin, Md. Ruhul; Rahman, S. M. Mahbobur; Mashud, Mohammad; Rabbi, Md. Fazle

2017-06-01

For modern aircrafts maneuvering control and reduction of power loss is a matter of great concern in Aerodynamics. Separation of airflow over the wings of aircraft at high angle of attack or at other situations is a hindrance to proper maneuvering control. As flow separation increases drag force on the aircraft, it consumes excess power. For these reasons much effort and research has gone into the design of aerodynamic surfaces which delay flow separation and keep the local flow attached for as long as possible. One of the simple and cost-effective way is to use a hinged flap on the wing of the aircraft, which lifts and self-adjusts to a position dependent on the aerodynamic forces and flap weight due to reversed flow at increasing angle of attack. There is a limitation of this kind of process. At very high angles of attack, the reversed flow would cause the flap to tip forwards entirely and the effect of the flap would vanish. For recovering this limitation an idea of controlling the movement or rotation of the flap has been proposed in this paper. A light surface was selected as a flap and was coupled to the shaft of a servo motor, which was placed on a model airfoil. For controlling the angle of rotation of the motor as well as the flap arbitrarily, an electronic circuit comprising necessary components was designed and applied to the servo motor successfully.

Understanding the Impact of Water on the Miscibility and Microstructure of Amorphous Solid Dispersions: An AFM-LCR and TEM-EDX Study.

PubMed

Li, Na; Gilpin, Christopher J; Taylor, Lynne S

2017-05-01

Miscibility is critical for amorphous solid dispersions (ASDs). Phase-separated ASDs are more prone to crystallization, and thus can lose their solubility advantage leading to product failure. Additionally, dissolution performance can be diminished as a result of phase separation in the ASD matrix. Water is known to induce phase separation during storage for some ASDs. However, the impact of water introduced during preparation has not been as thoroughly investigated to date. The purpose of this study was to develop a mechanistic understanding of the effect of water on the phase behavior and microstructure of ASDs. Evacetrapib and two polymers were selected as the model system. Atomic force microscopy coupled with Lorentz contact resonance, and transmission electron microscopy with energy dispersive X-ray spectroscopy were employed to evaluate the microstructure and composition of phase-separated ASDs. It was found that phase separation could be induced via two routes: solution-state phase separation during ASD formation caused by water absorption during film formation by a hydrophilic solvent, or solid-phase separation following exposure to high RH during storage. Water contents of as low as 2% in the organic solvent system used to dissolve the drug and polymer were found to result in phase separation in the resultant ASD film. These findings have profound implications on lab-scale ASD preparation and potentially also for industrial production. Additionally, these high-resolution imaging techniques combined with orthogonal analyses are powerful tools to visualize structural changes in ASDs, which in turn will enable better links to be made between ASD structure and performance.

Late metal-silicate separation on the IAB parent asteroid: Constraints from combined W and Pt isotopes and thermal modelling

NASA Astrophysics Data System (ADS)

Hunt, Alison C.; Cook, David L.; Lichtenberg, Tim; Reger, Philip M.; Ek, Mattias; Golabek, Gregor J.; Schönbächler, Maria

2018-01-01

The short-lived 182Hf-182W decay system is a powerful chronometer for constraining the timing of metal-silicate separation and core formation in planetesimals and planets. Neutron capture effects on W isotopes, however, significantly hamper the application of this tool. In order to correct for neutron capture effects, Pt isotopes have emerged as a reliable in-situ neutron dosimeter. This study applies this method to IAB iron meteorites, in order to constrain the timing of metal segregation on the IAB parent body. The ε182W values obtained for the IAB iron meteorites range from -3.61 ± 0.10 to -2.73 ± 0.09. Correlating εiPt with ε182W data yields a pre-neutron capture ε182W of -2.90 ± 0.06. This corresponds to a metal-silicate separation age of 6.0 ± 0.8 Ma after CAI for the IAB parent body, and is interpreted to represent a body-wide melting event. Later, between 10 and 14 Ma after CAI, an impact led to a catastrophic break-up and subsequent reassembly of the parent body. Thermal models of the interior evolution that are consistent with these estimates suggest that the IAB parent body underwent metal-silicate separation as a result of internal heating by short-lived radionuclides and accreted at around 1.4 ± 0.1 Ma after CAIs with a radius of greater than 60 km.

Inertial migration of elastic particles in a pressure-driven power-law fluid

NASA Astrophysics Data System (ADS)

Bowie, Samuel; Alexeev, Alexander

2016-11-01

Using three-dimensional computer simulations, we study the cross-stream migration of deformable particles in a channel filled with a non-Newtonian fluid driven by a pressure gradient. Our numerical approach integrates lattice Boltzmann method and lattice spring method in order to model fluid structural interactions of the elastic particle and the surrounding power fluid in the channel. The particles are modeled as elastic shells filled with a viscous fluid that are initially spherical. We focus on the regimes where the inertial effects cannot be neglected and cause cross-stream drift of particles. We probe the flow with different power law indexes including both the shear thickening and thinning fluids. We also examine migration of particles of with different elasticity and relative size. To isolate the non-Newtonian effects on particle migration, we compare the results with the inertial migration results found in the case where the channel is filled with a simple Newtonian fluid. The results can be useful for applications requiring high throughput separation, sorting, and focusing of both synthetic particles and biological cells in microfluidic devices. Financial support provided by National Science Foundation (NSF) Grant No. CMMI1538161.

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

Quashie, Edwin E.; Saha, Bidhan C.; Correa, Alfredo A.

Here, we present an ab initio study of the electronic stopping power of protons in copper over a wide range of proton velocities v = 0.02–10a.u. where we take into account nonlinear effects. Time-dependent density functional theory coupled with molecular dynamics is used to study electronic excitations produced by energetic protons. A plane-wave pseudopotential scheme is employed to solve the time-dependent Kohn-Sham equations for a moving ion in a periodic crystal. The electronic excitations and the band structure determine the stopping power of the material and alter the interatomic forces for both channeling and off-channeling trajectories. Our off-channeling results aremore » in quantitative agreement with experiments, and at low velocity they unveil a crossover region of superlinear velocity dependence (with a power of ~1.5) in the velocity range v = 0.07–0.3a.u., which we associate to the copper crystalline electronic band structure. The results are rationalized by simple band models connecting two separate regimes. We find that the limit of electronic stopping v → 0 is not as simple as phenomenological models suggest and it is plagued by band-structure effects.« less

On splice site prediction using weight array models: a comparison of smoothing techniques

NASA Astrophysics Data System (ADS)

Taher, Leila; Meinicke, Peter; Morgenstern, Burkhard

2007-11-01

In most eukaryotic genes, protein-coding exons are separated by non-coding introns which are removed from the primary transcript by a process called "splicing". The positions where introns are cut and exons are spliced together are called "splice sites". Thus, computational prediction of splice sites is crucial for gene finding in eukaryotes. Weight array models are a powerful probabilistic approach to splice site detection. Parameters for these models are usually derived from m-tuple frequencies in trusted training data and subsequently smoothed to avoid zero probabilities. In this study we compare three different ways of parameter estimation for m-tuple frequencies, namely (a) non-smoothed probability estimation, (b) standard pseudo counts and (c) a Gaussian smoothing procedure that we recently developed.

Metabolic Network Modeling of Microbial Communities

PubMed Central

Biggs, Matthew B.; Medlock, Gregory L.; Kolling, Glynis L.

2015-01-01

Genome-scale metabolic network reconstructions and constraint-based analysis are powerful methods that have the potential to make functional predictions about microbial communities. Current use of genome-scale metabolic networks to characterize the metabolic functions of microbial communities includes species compartmentalization, separating species-level and community-level objectives, dynamic analysis, the “enzyme-soup” approach, multi-scale modeling, and others. There are many challenges inherent to the field, including a need for tools that accurately assign high-level omics signals to individual community members, new automated reconstruction methods that rival manual curation, and novel algorithms for integrating omics data and engineering communities. As technologies and modeling frameworks improve, we expect that there will be proportional advances in the fields of ecology, health science, and microbial community engineering. PMID:26109480

Energy Efficient Engine acoustic supporting technology report

NASA Technical Reports Server (NTRS)

Lavin, S. P.; Ho, P. Y.

1985-01-01

The acoustic development of the Energy Efficient Engine combined testing and analysis using scale model rigs and an integrated Core/Low Spool demonstration engine. The scale model tests show that a cut-on blade/vane ratio fan with a large spacing (S/C = 2.3) is as quiet as a cut-off blade/vane ratio with a tighter spacing (S/C = 1.27). Scale model mixer tests show that separate flow nozzles are the noisiest, conic nozzles the quietest, with forced mixers in between. Based on projections of ICLS data the Energy Efficient Engine (E3) has FAR 36 margins of 3.7 EPNdB at approach, 4.5 EPNdB at full power takeoff, and 7.2 EPNdB at sideline conditions.

Multicomponent Separation Potential. Generalization of the Dirac Theory

NASA Astrophysics Data System (ADS)

Palkin, V. A.; Gadel‧shin, V. M.; Aleksandrov, O. E.; Seleznev, V. D.

2014-05-01

Formulas for the separation potential and the separative power have been obtained in the present work by generalizing the classical theory of Dirac, with the observance of his two axioms, to the case of a multicomponent mixture without considering a concrete cascade scheme. The resulting expressions are general characteristics of a separation process, since they are applicable to any separation methods and are independentof the form of the components in the mixture. They can be used in constructing actual cascades for separation of multicomponent mixtures and in determining the indices of their effi ciency.

Advanced dc-Traction-Motor Control System

NASA Technical Reports Server (NTRS)

Vittone, O.

1985-01-01

Motor-control concept for battery-powered vehicles includes stateof-the-art power-transistor switching and separate excitation of motor windings in traction and regenerative braking. Switching transistors and other components of power-conditioning subsystem operate under control of computer that coordinates traction, braking, and protective functions.

The simulation of organic rankine cycle power plant with n-pentane working fluid

NASA Astrophysics Data System (ADS)

Nurhilal, Otong; Mulyana, Cukup; Suhendi, Nendi; Sapdiana, Didi

2016-02-01

In the steam power plant in Indonesia the dry steam from separator directly used to drive the turbin. Meanwhile, brine from the separator with low grade temperature reinjected to the earth. The brine with low grade temperature can be converted indirectly to electrical power by organic Rankine cycle (ORC) methods. In ORC power plant the steam are released from vaporization of organic working fluid by brine. The steam released are used to drive an turbine which in connected to generator to convert the mechanical energy into electric energy. The objective of this research is the simulation ORC power plant with n-pentane as organic working fluid. The result of the simulation for brine temperature around 165°C and the pressure 8.001 bar optained the net electric power around 1173 kW with the cycle thermal efficiency 14.61% and the flow rate of n-pentane around 15.51 kg/s. This result enable to applied in any geothermal source in Indonesia.

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

Kung, C. C.; Kramer, G. J.; Johnson, E.

Reflectometry, which uses the microwave radar technique to probe the magnetically confined fusion plasmas, is a very powerful tool to observe the density fluctuations in the fusion plasmas. Typically, two or more microwave beams of different frequencies are used to study the plasma density fluctuations. The frequency separation between these two beams of the PPPL designed reflectometer system upgrade on the DIII-D tokamak can be varied over 18 GHz. Due to the performance of the associated electronics, the local oscillator (LO) power level at the LO port of the I/Q demodulator suffers more than 12 dB of power fluctuations whenmore » the frequency separation is varied. Thus, the I/Q demodulator performance is impaired. In order to correct this problem, a power leveling circuit is introduced in the PPPL upgrade. According to the test results, the LO power fluctuation was regulated to be within 1 dB for greater than 16 dB of input power variation over the full dynamic bandwidth of the receiver.« less

Two solar proton fluence models based on ground level enhancement observations

NASA Astrophysics Data System (ADS)

Raukunen, Osku; Vainio, Rami; Tylka, Allan J.; Dietrich, William F.; Jiggens, Piers; Heynderickx, Daniel; Dierckxsens, Mark; Crosby, Norma; Ganse, Urs; Siipola, Robert

2018-01-01

Solar energetic particles (SEPs) constitute an important component of the radiation environment in interplanetary space. Accurate modeling of SEP events is crucial for the mitigation of radiation hazards in spacecraft design. In this study we present two new statistical models of high energy solar proton fluences based on ground level enhancement (GLE) observations during solar cycles 19-24. As the basis of our modeling, we utilize a four parameter double power law function (known as the Band function) fits to integral GLE fluence spectra in rigidity. In the first model, the integral and differential fluences for protons with energies between 10 MeV and 1 GeV are calculated using the fits, and the distributions of the fluences at certain energies are modeled with an exponentially cut-off power law function. In the second model, we use a more advanced methodology: by investigating the distributions and relationships of the spectral fit parameters we find that they can be modeled as two independent and two dependent variables. Therefore, instead of modeling the fluences separately at different energies, we can model the shape of the fluence spectrum. We present examples of modeling results and show that the two methodologies agree well except for a short mission duration (1 year) at low confidence level. We also show that there is a reasonable agreement between our models and three well-known solar proton models (JPL, ESP and SEPEM), despite the differences in both the modeling methodologies and the data used to construct the models.

Separable concatenated codes with iterative map decoding for Rician fading channels

NASA Technical Reports Server (NTRS)

Lodge, J. H.; Young, R. J.

1993-01-01

Very efficient signalling in radio channels requires the design of very powerful codes having special structure suitable for practical decoding schemes. In this paper, powerful codes are obtained by combining comparatively simple convolutional codes to form multi-tiered 'separable' convolutional codes. The decoding of these codes, using separable symbol-by-symbol maximum a posteriori (MAP) 'filters', is described. It is known that this approach yields impressive results in non-fading additive white Gaussian noise channels. Interleaving is an inherent part of the code construction, and consequently, these codes are well suited for fading channel communications. Here, simulation results for communications over Rician fading channels are presented to support this claim.

Interpolatability distinguishes LOCC from separable von Neumann measurements

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

Childs, Andrew M.; Leung, Debbie; Mančinska, Laura

2013-11-15

Local operations with classical communication (LOCC) and separable operations are two classes of quantum operations that play key roles in the study of quantum entanglement. Separable operations are strictly more powerful than LOCC, but no simple explanation of this phenomenon is known. We show that, in the case of von Neumann measurements, the ability to interpolate measurements is an operational principle that sets apart LOCC and separable operations.

Design of in-flight fragment separator using high-power primary beams in the energy of a few hundred MeV/u

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

Kim, J. Y.; Kim, J. W.; Wan, W.

2015-07-15

An in-flight fragment separator usually requires large acceptance and high momentum resolution to minimize the loss of a rare isotope beam of interest produced at a thin target, which is especially important when {sup 238}U fission reactions in the energy of 200 MeV/u are used. The production target and beam dump are located in the pre-separator, where a beam power of up to 400 kW is dissipated. The area is surrounded by thick radiation shielding walls, which result in long drift spaces between adjacent magnetic components at various locations and an asymmetrical layout. Efforts have been made to minimize non-linearmore » effects in the pre-separator beam optics with trials of different separator configurations and correction schemes using COSY Infinity and GICOSY. The main separator is configured to be mirror symmetric such that correction with hexapole and octupole coils can be more readily applied. The separator configuration was finalized to allow the facility design to proceed and the key components including superconducting magnets have been designed and prototyped. In addition, the separator design has been evaluated using LISE++ including a set of wedge degraders at dispersive focal planes to improve the yield and purity of selected isotope beam.« less

Absorber Model: the Halo-like model for the Lyman-α forest

NASA Astrophysics Data System (ADS)

Iršič, Vid; McQuinn, Matthew

2018-04-01

We present a semi-analytic model for the Lyman-α forest that is inspired by the Halo Model. This model is built on the absorption line decomposition of the forest. Flux correlations are decomposed into those within each absorption line (the 1-absorber term) and those between separate lines (the 2-absorber term), treating the lines as biased tracers of the underlying matter fluctuations. While the nonlinear exponential mapping between optical depth and flux requires an infinite series of moments to calculate any statistic, we show that this series can be re-summed (truncating at the desired order in the linear matter overdensity). We focus on the z=2–3 line-of-sight power spectrum. Our model finds that 1-absorber term dominates the power on all scales, with most of its contribution coming from H I columns of 1014–1015 cm‑2, while the smaller 2-absorber contribution comes from lower columns that trace overdensities of a few. The prominence of the 1-absorber correlations indicates that the line-of-sight power spectrum is shaped principally by the lines' number densities and their absorption profiles, with correlations between lines contributing to a lesser extent. We present intuitive formulae for the effective optical depth as well as the large-scale limits of 1-absorber and 2-absorber terms, which simplify to integrals over the H I column density distribution with different equivalent-width weightings. With minimalist models for the bias of absorption systems and their peculiar velocity broadening, our model predicts values for the density bias and velocity gradient bias that are consistent with those found in simulations.

Neurobiological constraints on behavioral models of motivation.

PubMed

Nader, K; Bechara, A; van der Kooy, D

1997-01-01

The application of neurobiological tools to behavioral questions has produced a number of working models of the mechanisms mediating the rewarding and aversive properties of stimuli. The authors review and compare three models that differ in the nature and number of the processes identified. The dopamine hypothesis, a single system model, posits that the neurotransmitter dopamine plays a fundamental role in mediating the rewarding properties of all classes of stimuli. In contrast, both nondeprived/deprived and saliency attribution models claim that separate systems make independent contributions to reward. The former identifies the psychological boundary defined by the two systems as being between states of nondeprivation (e.g. food sated) and deprivation (e.g. hunger). The latter identifies a boundary between liking and wanting systems. Neurobiological dissociations provide tests of and explanatory power for behavioral theories of goal-directed behavior.

Untying Our Hands: Reconsidering Cyber as a Separate Instrument of National Power

DTIC Science & Technology

2017-04-21

to the level of an instrument of national power operating alongside the military, diplomatic, economic , and informational instruments of national...Reveron (Washington DC: Georgetown University Press, 2012), 178-182. 26 informational, military, and economic capabilities (also known by its...outcome.”41 Writing over seventy years ago, E. H. Carr provided a useful deconstruction of political power into military power, economic power, and

VISION User Guide - VISION (Verifiable Fuel Cycle Simulation) Model

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

Jacob J. Jacobson; Robert F. Jeffers; Gretchen E. Matthern

2009-08-01

The purpose of this document is to provide a guide for using the current version of the Verifiable Fuel Cycle Simulation (VISION) model. This is a complex model with many parameters; the user is strongly encouraged to read this user guide before attempting to run the model. This model is an R&D work in progress and may contain errors and omissions. It is based upon numerous assumptions. This model is intended to assist in evaluating “what if” scenarios and in comparing fuel, reactor, and fuel processing alternatives at a systems level for U.S. nuclear power. The model is not intendedmore » as a tool for process flow and design modeling of specific facilities nor for tracking individual units of fuel or other material through the system. The model is intended to examine the interactions among the components of a fuel system as a function of time varying system parameters; this model represents a dynamic rather than steady-state approximation of the nuclear fuel system. VISION models the nuclear cycle at the system level, not individual facilities, e.g., “reactor types” not individual reactors and “separation types” not individual separation plants. Natural uranium can be enriched, which produces enriched uranium, which goes into fuel fabrication, and depleted uranium (DU), which goes into storage. Fuel is transformed (transmuted) in reactors and then goes into a storage buffer. Used fuel can be pulled from storage into either separation of disposal. If sent to separations, fuel is transformed (partitioned) into fuel products, recovered uranium, and various categories of waste. Recycled material is stored until used by its assigned reactor type. Note that recovered uranium is itself often partitioned: some RU flows with recycled transuranic elements, some flows with wastes, and the rest is designated RU. RU comes out of storage if needed to correct the U/TRU ratio in new recycled fuel. Neither RU nor DU are designated as wastes. VISION is comprised of several Microsoft Excel input files, a Powersim Studio core, and several Microsoft Excel output files. All must be co-located in the same folder on a PC to function. We use Microsoft Excel 2003 and have not tested VISION with Microsoft Excel 2007. The VISION team uses both Powersim Studio 2005 and 2009 and it should work with either.« less

Application Study of a High Temperature Superconducting Fault Current Limiter for Electric Power System

NASA Astrophysics Data System (ADS)

Naito, Yuji; Shimizu, Iwao; Yamaguchi, Iwao; Kaiho, Katsuyuki; Yanabu, Satoru

Using high temperature superconductor, a Superconducting Fault Current Limiter (SFCL) was made and tested. Superconductor and vacuum interrupter as commutation switch are connected in parallel with bypass coil. When a fault occurs and the excessive current flows, superconductor is first quenched and the current is transferred to bypass coil because on voltage drop of superconductor. At the same time, since magnetic field is generated by current which flows in bypass coil, commutation switch is immediately driven by electromagnetic repulsion plate connected to driving rod of vacuum interrupter, and superconductor is separated from this circuit. Using the testing model, we could separate the superconductor from a circuit due to movement of vacuum interrupter within half-cycle current and transfer all current to bypass coil. Since operation of a commutation switch is included in current limiting operation of this testing model, it is one of helpful circuit of development of SFCL in the future. Moreover, since it can make the consumed energy of superconductor small during fault state due to realization of high-speed switch with simple composition, the burden of superconductor is reduced compared with conventional resistive type SFCL and it is considered that the flexibility of a SFCL design increases. Cooperation with a circuit breaker was also considered, the trial calculation of a parameter and energy of operation is conducted and discussion in the case of installing the SFCL to electric power system is made.

Modeling and properties of an ion-exchanged optical variable attenuator

NASA Astrophysics Data System (ADS)

Orignac, Xavier; Ingenhoff, Jan; Fabricius, Norbert

1999-03-01

The optical signal power needs to be regulated at some locations in transmission lines. That can be done with the help of optical variable attenuators (OVA), devices which allows for the control of their insertion loss. This work describes the design and properties of some OVAs fabricated by the ion-exchange technique. The OVA functionality relies on a Mach-Zehnder structure, where the output optical intensity is tuned via the change in optical path along one of the two interferometer arms. Here, the optical path is varied through thermo-optic effect (change of refractive index with temperature). Modelling is first addressed: a mostly qualitative theoretical investigation is used to clarify how the fabrication parameters (burial depth and Mach-Zehnder arm separation distance) can be related to the OVAs properties (attenuation dynamic, switching power, settling time, PDL). Properties of fabricated OVAs are presented in a second part. They are compared with other existing products. The relationship between fabrication parameters and properties is also re-examined in light of these results.

Gasification in pulverized coal flames. First annual progress report, July 1975--June 1976

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

Lenzer, R. C.; George, P. E.; Thomas, J. F.

1976-07-01

This project concerns the production of power and synthesis gas from pulverized coal via suspension gasification. Swirling flow in both concentric jet and cyclone gasifiers will separate oxidation and reduction zones. Gasifier performance will be correlated with internally measured temperature and concentration profiles. A literature review of vortex and cyclone reactors is complete. Preliminary reviews of confined jet reactors and pulverized coal reaction models have also been completed. A simple equilibrium model for power gas production is in agreement with literature correlations. Cold gas efficiency is not a suitable performance parameter for combined cycle operation. The coal handling facility, equippedmore » with crusher, pulverizer and sieve shaker, is in working order. Test cell flow and electrical systems have been designed, and most of the equipment has been received. Construction of the cyclone gasifier has begun. A preliminary design for the gas sampling system, which will utilize a UTI Q-30C mass spectrometer, has been developed.« less

Deriving photometric redshifts using fuzzy archetypes and self-organizing maps - I. Methodology

NASA Astrophysics Data System (ADS)

Speagle, Joshua S.; Eisenstein, Daniel J.

2017-07-01

We propose a method to substantially increase the flexibility and power of template fitting-based photometric redshifts by transforming a large number of galaxy spectral templates into a corresponding collection of 'fuzzy archetypes' using a suitable set of perturbative priors designed to account for empirical variation in dust attenuation and emission-line strengths. To bypass widely separated degeneracies in parameter space (e.g. the redshift-reddening degeneracy), we train self-organizing maps (SOMs) on large 'model catalogues' generated from Monte Carlo sampling of our fuzzy archetypes to cluster the predicted observables in a topologically smooth fashion. Subsequent sampling over the SOM then allows full reconstruction of the relevant probability distribution functions (PDFs). This combined approach enables the multimodal exploration of known variation among galaxy spectral energy distributions with minimal modelling assumptions. We demonstrate the power of this approach to recover full redshift PDFs using discrete Markov chain Monte Carlo sampling methods combined with SOMs constructed from Large Synoptic Survey Telescope ugrizY and Euclid YJH mock photometry.

3D Monte Carlo model with direct photon flux recording for optimal optogenetic light delivery

NASA Astrophysics Data System (ADS)

Shin, Younghoon; Kim, Dongmok; Lee, Jihoon; Kwon, Hyuk-Sang

2017-02-01

Configuring the light power emitted from the optical fiber is an essential first step in planning in-vivo optogenetic experiments. However, diffusion theory, which was adopted for optogenetic research, precluded accurate estimates of light intensity in the semi-diffusive region where the primary locus of the stimulation is located. We present a 3D Monte Carlo model that provides an accurate and direct solution for light distribution in this region. Our method directly records the photon trajectory in the separate volumetric grid planes for the near-source recording efficiency gain, and it incorporates a 3D brain mesh to support both homogeneous and heterogeneous brain tissue. We investigated the light emitted from optical fibers in brain tissue in 3D, and we applied the results to design optimal light delivery parameters for precise optogenetic manipulation by considering the fiber output power, wavelength, fiber-to-target distance, and the area of neural tissue activation.

Human comment dynamics in on-line social systems

NASA Astrophysics Data System (ADS)

Wu, Ye; Zhou, Changsong; Chen, Maoying; Xiao, Jinghua; Kurths, Jürgen

2010-12-01

Human comment is studied using data from ‘tianya’ which is one of the most popular on-line social systems in China. We found that the time interval between two consecutive comments on the same topic, called inter-event time, follows a power-law distribution. This result shows that there is no characteristic decay time on a topic. It allows for very long periods without comments that separate bursts of intensive comments. Furthermore, the frequency of a different ID commenting on a topic also follows a power-law distribution. It indicates that there are some “hubs” in the topic who lead the direction of the public opinion. Based on the personal comments habit, a model is introduced to explain these phenomena. The numerical simulations of the model fit well with the empirical results. Our findings are helpful for discovering regular patterns of human behavior in on-line society and the evolution of the public opinion on the virtual as well as real society.

Beyond the plane-parallel approximation for redshift surveys

NASA Astrophysics Data System (ADS)

Castorina, Emanuele; White, Martin

2018-06-01

Redshift -space distortions privilege the location of the observer in cosmological redshift surveys, breaking the translational symmetry of the underlying theory. This violation of statistical homogeneity has consequences for the modelling of clustering observables, leading to what are frequently called `wide-angle effects'. We study these effects analytically, computing their signature in the clustering of the multipoles in configuration and Fourier space. We take into account both physical wide-angle contributions as well as the terms generated by the galaxy selection function. Similar considerations also affect the way power spectrum estimators are constructed. We quantify in an analytical way the biases that enter and clarify the relation between what we measure and the underlying theoretical modelling. The presence of an angular window function is also discussed. Motivated by this analysis, we present new estimators for the three dimensional Cartesian power spectrum and bispectrum multipoles written in terms of spherical Fourier-Bessel coefficients. We show how the latter have several interesting properties, allowing in particular a clear separation between angular and radial modes.

Transionospheric Propagation of VLF Transmitter Signals

NASA Astrophysics Data System (ADS)

Cohen, M.; Inan, U. S.; Lehtinen, N. G.

2012-12-01

Ground based Very Low Frequency (VLF, 3-30 kHz) radio transmitters may play a significant role in precipitation of inner belt (L<2.5) energetic Van Allen electrons. Initial analyses of the total contribution of VLF transmitters utilized models of transionospheric propagation, but some recent studies have suggested that those models may overestimate (by 20-100 dB) the VLF energy reaching the magnetosphere. One possible cause of this discrepancy was suggested to be conversion of wave energy into electrostatic modes in the D, E, and F regions, from ionospheric density irregularities, either natural or generated by the transmitter heating itself. The DEMETER satellite built a six year history of continuous and global survey mode data which, when combined, yields detailed pictures of the radiation pattern from many transmitters into space at 680 km, with 25 km resolution, and clear features like the interference pattern on the ground mapped upwards. With both E and B survey mode data, we can also directly approximate the total power injected into the magnetosphere from each transmitter, separately for day and night, as well as the power arriving at the conjugate region. We find no detectable variation of signal intensity with geomagnetic conditions. We find evidence of transmitter heating affecting the transionospheric propagation of other transmitters. We find that the power reaching the conjugate region is a large fraction of the power injected above the transmitter. We then employ a full wave model to simulate VLF transmitter transionospheric propagation, calculating the electromagnetic fields and power flux injected into the magnetosphere. Although the model does not include ionospheric irregularities, the radiation pattern largely matches the observed one, and the total power calculated is within 6 dB of observations for every transmitter, both day and night, and across a range of low to middle latitudes and transmitter powers. We thus conclude that the effect of ionospheric irregularities on VLF wave injection into the radiation belts may be small, if present at all.The nighttime radiation pattern of NWC at 700 km altitude, derived by averaging 6 years of DEMETER survey mode data.

Distillation and Air Stripping Designs for the Lunar Surface

NASA Technical Reports Server (NTRS)

Boul, Peter J.; Lange, Kevin E.; Conger, Bruce; Anderson, Molly

2009-01-01

Air stripping and distillation are two different gravity-based methods, which may be applied to the purification of wastewater on the lunar base. These gravity-based solutions to water processing are robust physical separation techniques, which may be advantageous to many other techniques for their simplicity in design and operation. The two techniques can be used in conjunction with each other to obtain high purity water. The components and feed compositions for modeling waste water streams are presented in conjunction with the Aspen property system for traditional stage distillation models and air stripping models. While the individual components for each of the waste streams will vary naturally within certain bounds, an analog model for waste water processing is suggested based on typical concentration ranges for these components. Target purity levels for the for recycled water are determined for each individual component based on NASA s required maximum contaminant levels for potable water Distillation processes are modeled separately and in tandem with air stripping to demonstrate the potential effectiveness and utility of these methods in recycling wastewater on the Moon. Optimum parameters such as reflux ratio, feed stage location, and processing rates are determined with respect to the power consumption of the process. Multistage distillation is evaluated for components in wastewater to determine the minimum number of stages necessary for each of 65 components in humidity condensate and urine wastewater mixed streams. Components of the wastewater streams are ranked by Henry s Law Constant and the suitability of air stripping in the purification of wastewater in terms of component removal is evaluated. Scaling factors for distillation and air stripping columns are presented to account for the difference in the lunar gravitation environment. Commercially available distillation and air stripping units which are considered suitable for Exploration Life Support are presented. The advantages to the various designs are summarized with respect to water purity levels, power consumption, and processing rates.