Sample records for ac flow tests

  1. DC-biased AC-electroosmotic and AC-electrothermal flow mixing in microchannels.

    PubMed

    Ng, Wee Yang; Goh, Shireen; Lam, Yee Cheong; Yang, Chun; Rodríguez, Isabel

    2009-03-21

    This paper presents a novel approach of mixing two laminar flowing streams in microchannels. The mixer consists of a pair of electrodes disposed along a fluidic channel. By energizing the electrodes with a DC-biased (2.5 V) AC voltage (20 Vpp), an electrokinetic flow is induced with a flow profile perpendicular to that of the incoming laminar streams of liquids to be mixed. As a result, the flow lines of the incoming streams and the induced flow are forced to crossover and very efficient stirring and mixing at short mixing length can be achieved. The mixer can be operated from the AC-electroosmotic (ACEO) (sigma=1 mS/m, f=100 kHz) to the AC-electrothermal (ACET) (sigma=500 mS/m, f=500 kHz) flow regimes. The mixing efficiency in the ACEO regime was 92%, with a mixing length of 600 microm (Q=2 microL/min), an estimated mixing time of 69 ms and an induced ACEO flow velocity of approximately 725 microm/s. The mixing efficiency in the ACET regime was 65% for a mixing length of approximately 1200 microm. The mixer is efficient and suitable for mixing reagents in a fluid media from low to high conductivity as required in diverse microfluidic applications.

  2. Ac electroosmotic flows above coplanar electrodes

    NASA Astrophysics Data System (ADS)

    Kweon Suh, Yong

    2009-03-01

    Interactive numerical method has been proposed to calculate the ac electroosmotic flows above a pair of coplanar electrodes. The thin electrical triple layer (ETL) has been modeled by an asymptotic theory developed by the authors. The model corresponds to a simple dynamic equation for the surface charge density representing the integrated charge over the inner layer. Interactive calculation of the dynamic equation and the Laplace equation for several periods of ac frequency then yielded steady-state distribution of potential and the potential drop across the Stern and inner layers. The Smoluchowski's slip velocity was then determined from those two set of data and used as the boundary condition for the calculation of the Stokes' flow above the electrodes. We have shown that our solutions compared well with the experimental data reported in the literature. We investigated the effect of various parameters on the slip velocity distribution, such as the ac frequency, the electrode length, the effective Stern-layer thickness and the adsorption coefficients.

  3. Faradaic AC Electrokinetic Flow and Particle Traps

    NASA Astrophysics Data System (ADS)

    Ben, Yuxing; Chang, Hsueh-Chia

    2004-11-01

    Faradaic reaction at higher voltages can produce co-ion polarization at AC electrodes instead of counter-ion polarization due to capacitive charging from the bulk. The Faradaic co-ion polarization also does not screen the external field and hence can produce large net electro-kinetic flows at frequencies lower than the inverse RC time of the double layer. Due to the opposite polarization of capacitve and Faradaic charging, we can reverse the direction of AC flows on electrodes by changing the voltage and frequency. Particles and bacteria are trapped and then dispersed at stagnation lines, at locations predicted by our theory, by using these two flows sequentially. This technique offers a good way to concentrate and detect bacteria.

  4. Dielectrophoretic particle-particle interaction under AC electrohydrodynamic flow conditions.

    PubMed

    Lee, Doh-Hyoung; Yu, Chengjie; Papazoglou, Elisabeth; Farouk, Bakhtier; Noh, Hongseok M

    2011-09-01

    We used the Maxwell stress tensor method to understand dielectrophoretic particle-particle interactions and applied the results to the interpretation of particle behaviors under alternating current (AC) electrohydrodynamic conditions such as AC electroosmosis (ACEO) and electrothermal flow (ETF). Distinct particle behaviors were observed under ACEO and ETF. Diverse particle-particle interactions observed in experiments such as particle clustering, particles keeping a certain distance from each other, chain and disc formation and their rotation, are explained based on the numerical simulation data. The improved understanding of particle behaviors in AC electrohydrodynamic flows presented here will enable researchers to design better particle manipulation strategies for lab-on-a-chip applications. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  5. An electrohydrodynamic flow in ac electrowetting.

    PubMed

    Lee, Horim; Yun, Sungchan; Ko, Sung Hee; Kang, Kwan Hyoung

    2009-12-17

    In ac electrowetting, hydrodynamic flows occur within a droplet. Two distinct flow patterns were observed, depending on the frequency of the applied electrical signal. The flow at low-frequency range was explained in terms of shape oscillation and a steady streaming process in conjunction with contact line oscillation. The origin of the flow at high-frequency range has not yet been explained. We suggest that the high-frequency flow originated mainly from the electrothermal effect, in which electrical charge is generated due to the gradient of electrical conductivity and permittivity, which is induced by the Joule heating of fluid medium. To support our argument, we analyzed the flow field numerically while considering the electrical body force generated by the electrothermal effect. We visualized the flow pattern and measured the flow velocity inside the droplet. The numerical results show qualitative agreement with experimental results with respect to electric field and frequency dependence of flow velocity. The effects of induced-charge electro-osmosis, natural convection, and the Marangoni flow are discussed.

  6. Bi-directional flow induced by an AC electroosmotic micropump with DC voltage bias.

    PubMed

    Islam, Nazmul; Reyna, Jairo

    2012-04-01

    This paper discusses the principle of biased alternating current electroosmosis (ACEO) and its application to move the bulk fluid in a microchannel, as an alternative to mechanical pumping methods. Previous EO-driven flow research has looked at the effect of electrode asymmetry and transverse traveling wave forms on the performance of electroosmotic pumps. This paper presents an analysis that was conducted to assess the effect of combining an AC signal with a DC (direct current) bias when generating the electric field needed to impart electroosmosis (EO) within a microchannel. The results presented here are numerical and experimental. The numerical results were generated through simulations performed using COMSOL 3.5a. Currently available theoretical models for EO flows were embedded in the software and solved numerically to evaluate the effects of channel geometry, frequency of excitation, electrode array geometry, and AC signal with a DC bias on the flow imparted on an electrically conducting fluid. Simulations of the ACEO flow driven by a constant magnitude of AC voltage over symmetric electrodes did not indicate relevant net flows. However, superimposing a DC signal over the AC signal on the same symmetric electrode array leads to a noticeable net forward flow. Moreover, changing the polarity of electrical signal creates a bi-directional flow on symmetrical electrode array. Experimental flow measurements were performed on several electrode array configurations. The mismatch between the numerical and experimental results revealed the limitations of the currently available models for the biased EO. However, they confirm that using a symmetric electrode array excited by an AC signal with a DC bias leads to a significant improvement in flow rates in comparison to the flow rates obtained in an asymmetric electrode array configuration excited just with an AC signal. © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  7. Electroosmotic Flow Driven by DC and AC Electric Fields in Curved Microchannels

    NASA Astrophysics Data System (ADS)

    Chen, Jia-Kun; Luo, Win-Jet; Yang, Ruey-Jen

    2006-10-01

    The purpose of this study is to investigate electroosmotic flows driven by externally applied DC and AC electric fields in curved microchannels. For the DC electric driving field, the velocity distribution and secondary flow patterns are investigated in microchannels with various curvature ratios. We use the Dean number to describe the curvature effect of the flow field in DC electric field. The result implies that the effect of curvatures and the strength of the secondary flows become get stronger when the curvature ratio of C/A (where C is the radius of curvature of the microchannel and A is the half-height of rectangular curved tube.) is smaller. For the AC electric field, the velocity distribution and secondary flow patterns are investigated for driving frequencies in the range of 2.0 kHz (\\mathit{Wo}=0.71) to 11 kHz (\\mathit{Wo}=1.66). The numerical results reveal that the velocity at the center of the microchannel becomes lower at higher frequencies of the AC electric field and the strength of the secondary flow decreases. When the applied frequency exceeds 3.0 kHz (\\mathit{Wo}=0.87), vortices are no longer observed at the corners of the microchannel. Therefore, it can be concluded that the secondary flow induced at higher AC electric field frequencies has virtually no effect on the axial flow field in the microchannel.

  8. Chance-Constrained AC Optimal Power Flow: Reformulations and Efficient Algorithms

    DOE PAGES

    Roald, Line Alnaes; Andersson, Goran

    2017-08-29

    Higher levels of renewable electricity generation increase uncertainty in power system operation. To ensure secure system operation, new tools that account for this uncertainty are required. Here, in this paper, we adopt a chance-constrained AC optimal power flow formulation, which guarantees that generation, power flows and voltages remain within their bounds with a pre-defined probability. We then discuss different chance-constraint reformulations and solution approaches for the problem. Additionally, we first discuss an analytical reformulation based on partial linearization, which enables us to obtain a tractable representation of the optimization problem. We then provide an efficient algorithm based on an iterativemore » solution scheme which alternates between solving a deterministic AC OPF problem and assessing the impact of uncertainty. This more flexible computational framework enables not only scalable implementations, but also alternative chance-constraint reformulations. In particular, we suggest two sample based reformulations that do not require any approximation or relaxation of the AC power flow equations.« less

  9. Chance-Constrained AC Optimal Power Flow for Distribution Systems With Renewables

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

    DallAnese, Emiliano; Baker, Kyri; Summers, Tyler

    This paper focuses on distribution systems featuring renewable energy sources (RESs) and energy storage systems, and presents an AC optimal power flow (OPF) approach to optimize system-level performance objectives while coping with uncertainty in both RES generation and loads. The proposed method hinges on a chance-constrained AC OPF formulation where probabilistic constraints are utilized to enforce voltage regulation with prescribed probability. A computationally more affordable convex reformulation is developed by resorting to suitable linear approximations of the AC power-flow equations as well as convex approximations of the chance constraints. The approximate chance constraints provide conservative bounds that hold for arbitrarymore » distributions of the forecasting errors. An adaptive strategy is then obtained by embedding the proposed AC OPF task into a model predictive control framework. Finally, a distributed solver is developed to strategically distribute the solution of the optimization problems across utility and customers.« less

  10. Test plan for performance testing of the Eaton AC-3 electric vehicle

    NASA Astrophysics Data System (ADS)

    Crumley, R.; Heiselmann, H. W.

    1985-04-01

    An alternating current (ac) propulsion system for an electric vehicle was developed and tested. The test bed vehicle is a modified 1981 Mercury Lynx. The test plan was prepared specifically for the third modification to this test bed and identified as the Eaton AC-3. The scope of the testing done on the Eaton AC-3 includes coastdown and dynamometer tests but does not include environmental, on-road, or track testing. Coastdown testing is performed in accordance with SAE J-1263 (SAE Recommended Practice for Road Load Measurement and Dynamometer Simulation Using Coastdown Techniques).

  11. Distributed Optimal Power Flow of AC/DC Interconnected Power Grid Using Synchronous ADMM

    NASA Astrophysics Data System (ADS)

    Liang, Zijun; Lin, Shunjiang; Liu, Mingbo

    2017-05-01

    Distributed optimal power flow (OPF) is of great importance and challenge to AC/DC interconnected power grid with different dispatching centres, considering the security and privacy of information transmission. In this paper, a fully distributed algorithm for OPF problem of AC/DC interconnected power grid called synchronous ADMM is proposed, and it requires no form of central controller. The algorithm is based on the fundamental alternating direction multiplier method (ADMM), by using the average value of boundary variables of adjacent regions obtained from current iteration as the reference values of both regions for next iteration, which realizes the parallel computation among different regions. The algorithm is tested with the IEEE 11-bus AC/DC interconnected power grid, and by comparing the results with centralized algorithm, we find it nearly no differences, and its correctness and effectiveness can be validated.

  12. Strengthening the SDP Relaxation of AC Power Flows with Convex Envelopes, Bound Tightening, and Valid Inequalities

    DOE PAGES

    Coffrin, Carleton James; Hijazi, Hassan L; Van Hentenryck, Pascal R

    2016-12-01

    Here this work revisits the Semidefine Programming (SDP) relaxation of the AC power flow equations in light of recent results illustrating the benefits of bounds propagation, valid inequalities, and the Convex Quadratic (QC) relaxation. By integrating all of these results into the SDP model a new hybrid relaxation is proposed, which combines the benefits from all of these recent works. This strengthened SDP formulation is evaluated on 71 AC Optimal Power Flow test cases from the NESTA archive and is shown to have an optimality gap of less than 1% on 63 cases. This new hybrid relaxation closes 50% ofmore » the open cases considered, leaving only 8 for future investigation.« less

  13. On-Chip AC self-test controller

    DOEpatents

    Flanagan, John D [Rhinebeck, NY; Herring, Jay R [Poughkeepsie, NY; Lo, Tin-Chee [Fishkill, NY

    2009-09-29

    A system for performing AC self-test on an integrated circuit that includes a system clock for normal operation is provided. The system includes the system clock, self-test circuitry, a first and second test register to capture and launch test data in response to a sequence of data pulses, and a logic circuit to be tested. The self-test circuitry includes an AC self-test controller and a clock splitter. The clock splitter generates the sequence of data pulses including a long data capture pulse followed by an at speed data launch pulse and an at speed data capture pulse followed by a long data launch pulse. The at speed data launch pulse and the at speed data capture pulse are generated for a common cycle of the system clock.

  14. AC Electric-Field-Induced Fluid Flow in Microelectrodes.

    PubMed

    Ramos; Morgan; Green; Castellanos

    1999-09-15

    During the AC electrokinetic manipulation of particles in suspension on microelectrode structures, strong frequency-dependent fluid flow is observed. The fluid movement is predominant at frequencies below the reciprocal charge relaxation time, with a reproducible pattern occurring close to and across the electrode surface. This paper reports measurements of the fluid velocity as a function of frequency and position across the electrode. Evidence is presented indicating that the flow occurs due to electroosmotic stress arising from the interaction of the electric field and the electrical double layer on the electrodes. The electrode polarization plays a significant role in controlling the frequency dependence of the flow. Copyright 1999 Academic Press.

  15. Instantaneous velocity measurement of AC electroosmotic flows by laser induced fluorescence photobleaching anemometer with high temporal resolution

    NASA Astrophysics Data System (ADS)

    Zhao, Wei; Yang, Fang; Qiao, Rui; Wang, Guiren; Rui Qiao Collaboration

    2015-11-01

    Understanding the instantaneous response of flows to applied AC electric fields may help understand some unsolved issues in induced-charge electrokinetics and enhance performance of microfluidic devices. Since currently available velocimeters have difficulty in measuring velocity fluctuations with frequency higher than 1 kHz, most experimental studies so far focus only on the average velocity measurement in AC electrokinetic flows. Here, we present measurements of AC electroosmotic flow (AC-EOF) response time in microchannels by a novel velocimeter with submicrometer spatial resolution and microsecond temporal resolution, i.e. laser-induced fluorescence photobleaching anemometer (LIFPA). Several parameters affecting the AC-EOF response time to the applied electric signal were investigated, i.e. channel length, transverse position and solution conductivity. The experimental results show that the EOF response time under a pulsed electric field decreases with the reduction of the microchannel length, distance between the detection position to the wall and the conductivity of the solution. This work could provide a new powerful tool to measure AC electrokinetics and enhance our understanding of AC electrokinetic flows.

  16. Transient electroosmotic flow induced by AC electric field in micro-channel with patchwise surface heterogeneities.

    PubMed

    Luo, Win-Jet

    2006-03-15

    This paper investigates two-dimensional, time-dependent electroosmotic flow driven by an AC electric field via patchwise surface heterogeneities distributed along the micro-channel walls. The time-dependent flow fields through the micro-channel are simulated for various patchwise heterogeneous surface patterns using the backwards-Euler time stepping numerical method. Different heterogeneous surface patterns are found to create significantly different electrokinetic transport phenomena. The transient behavior characteristics of the generated electroosmotic flow are then discussed in terms of the influence of the patchwise surface heterogeneities, the direction of the applied AC electric field, and the velocity of the bulk flow. It is shown that the presence of oppositely charged surface heterogeneities on the micro-channel walls results in the formation of localized flow circulations within the bulk flow. These circulation regions grow and decay periodically in phase with the applied periodic AC electric field intensity. The location and rotational direction of the induced circulations are determined by the directions of the bulk flow velocity and the applied electric field.

  17. Electroosmosis through a Cation-Exchange Membrane: Effect of an ac Perturbation on the Electroosmotic Flow.

    PubMed

    Barragán; Ruíz Bauzá C

    2000-10-15

    Electroosmosis experiments through a cation-exchange membrane have been performed using NaCl solutions in different experimental situations. The influence of an alternating (ac) sinusoidal perturbation, of known angular frequency and small amplitude, superimposed to the usual applied continuous (dc) signal on the electroosmotic flow has been studied. The experimental results show that the presence of the ac perturbation affects the electroosmotic flow value, depending on the frequency of the ac signal and on the solution stirring conditions. In the frequency range studied, two regions have been observed where the electroosmotic flow reaches a maximum value: one at low frequencies ( approximately Hz); and another at frequencies of the order of kHz. These regions could be related to membrane relaxation phenomena. Copyright 2000 Academic Press.

  18. Debris-flow runout predictions based on the average channel slope (ACS)

    USGS Publications Warehouse

    Prochaska, A.B.; Santi, P.M.; Higgins, J.D.; Cannon, S.H.

    2008-01-01

    Prediction of the runout distance of a debris flow is an important element in the delineation of potentially hazardous areas on alluvial fans and for the siting of mitigation structures. Existing runout estimation methods rely on input parameters that are often difficult to estimate, including volume, velocity, and frictional factors. In order to provide a simple method for preliminary estimates of debris-flow runout distances, we developed a model that provides runout predictions based on the average channel slope (ACS model) for non-volcanic debris flows that emanate from confined channels and deposit on well-defined alluvial fans. This model was developed from 20 debris-flow events in the western United States and British Columbia. Based on a runout estimation method developed for snow avalanches, this model predicts debris-flow runout as an angle of reach from a fixed point in the drainage channel to the end of the runout zone. The best fixed point was found to be the mid-point elevation of the drainage channel, measured from the apex of the alluvial fan to the top of the drainage basin. Predicted runout lengths were more consistent than those obtained from existing angle-of-reach estimation methods. Results of the model compared well with those of laboratory flume tests performed using the same range of channel slopes. The robustness of this model was tested by applying it to three debris-flow events not used in its development: predicted runout ranged from 82 to 131% of the actual runout for these three events. Prediction interval multipliers were also developed so that the user may calculate predicted runout within specified confidence limits. ?? 2008 Elsevier B.V. All rights reserved.

  19. Development of a hardware-based AC microgrid for AC stability assessment

    NASA Astrophysics Data System (ADS)

    Swanson, Robert R.

    As more power electronic-based devices enable the development of high-bandwidth AC microgrids, the topic of microgrid power distribution stability has become of increased interest. Recently, researchers have proposed a relatively straightforward method to assess the stability of AC systems based upon the time-constants of sources, the net bus capacitance, and the rate limits of sources. In this research, a focus has been to develop a hardware test system to evaluate AC system stability. As a first step, a time domain model of a two converter microgrid was established in which a three phase inverter acts as a power source and an active rectifier serves as an adjustable constant power AC load. The constant power load can be utilized to create rapid power flow transients to the generating system. As a second step, the inverter and active rectifier were designed using a Smart Power Module IGBT for switching and an embedded microcontroller as a processor for algorithm implementation. The inverter and active rectifier were designed to operate simultaneously using a synchronization signal to ensure each respective local controller operates in a common reference frame. Finally, the physical system was created and initial testing performed to validate the hardware functionality as a variable amplitude and variable frequency AC system.

  20. Photovoltaic Inverter Controllers Seeking AC Optimal Power Flow Solutions

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

    Dall'Anese, Emiliano; Dhople, Sairaj V.; Giannakis, Georgios B.

    This paper considers future distribution networks featuring inverter-interfaced photovoltaic (PV) systems, and addresses the synthesis of feedback controllers that seek real- and reactive-power inverter setpoints corresponding to AC optimal power flow (OPF) solutions. The objective is to bridge the temporal gap between long-term system optimization and real-time inverter control, and enable seamless PV-owner participation without compromising system efficiency and stability. The design of the controllers is grounded on a dual ..epsilon..-subgradient method, while semidefinite programming relaxations are advocated to bypass the non-convexity of AC OPF formulations. Global convergence of inverter output powers is analytically established for diminishing stepsize rules formore » cases where: i) computational limits dictate asynchronous updates of the controller signals, and ii) inverter reference inputs may be updated at a faster rate than the power-output settling time.« less

  1. Resonant AC power system proof-of-concept test program

    NASA Technical Reports Server (NTRS)

    Wappes, Loran J.

    1986-01-01

    Proof-of-concept testing was performed on a 20-kHz, resonant power system breadboard from 1981 through 1985. The testing began with the evaluation of a single, 1.0-kW resonant inverter and progressed to the testing of breadboard systems with higher power levels and more capability. The final breadboard configuration tested was a 25.0-kW breadboard with six inverters providing power to three user-interface modules over a 50-meter, 20-kHz bus. The breadboard demonstrated the ability to synchronize multiple resonant inverters to power a common bus. Single-phase and three-phase 20-kHz power distribution was demonstrated. Simple conversion of 20-kHz to dc and variable-frequency ac was demonstrated as was bidirectional power flow between 20-kHz and dc. Steady state measurements of efficiency, power-factor tolerance, and conducted emissions and conducted susceptibility were made. In addition, transient responses were recorded for such conditions as start up, shut down, load changes. The results showed the 20-kHz resonant system to be a desirable technology for a spacecraft power management and distribution system with multiple users and a utility-type bus.

  2. The Effect of a Shear Flow on the Uptake of LDL and Ac-LDL by Cultured Vascular Endothelial Cells

    NASA Astrophysics Data System (ADS)

    Niwa, Koichi; Karino, Takeshi

    The effects of a shear flow on the uptake of fluorescence-labeled low-density lipoprotein (DiI-LDL), acetylated LDL (DiI-Ac-LDL), and lucifer yellow (LY; a tracer of fluid-phase endocytosis) by cultured bovine aortic ECs were studied using a rotating-disk shearing apparatus. It was found that 2hours’ exposure of ECs to a laminar shear flow that imposed ECs an area-mean shear stress of 10dynes/cm2 caused an increase in the uptake of DiI-LDL and LY. By contrast, the uptake of DiI-Ac-LDL was decreased by exposure of the ECs to a shear flow. Addition of dextran sulfate (DS), a competitive inhibitor of scavenger receptors, reversed the effect of a shear flow on the uptake of DiI-Ac-LDL, resulting in an increase by the imposition of a shear flow, while the uptake of DiI-LDL and LY remained unaffected. It was concluded that a shear flow promotes the endocytosis of DiI-LDL and LY by ECs, but suppresses the uptake of DiI-Ac-LDL by ECs by inhibiting scavenger receptor-mediated endocytosis.

  3. Electrodeposition of Au/Ag bimetallic dendrites assisted by Faradaic AC-electroosmosis flow

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

    Ji, Jianlong; Li, Pengwei; Sang, Shengbo, E-mail: sbsang@tyut.edu.cn

    2014-03-15

    Au/Ag bimetallic dendrites were synthesized successfully from the corresponding aqueous solution via the AC electrodeposition method. Both of the morphologies and compositions could be tuned by the electrolyte concentration and AC frequency. The prepared bimetallic dendrites were characterized by scanning electron microscopy (SEM), energy dispersive X-ray spectrometer (EDS), transmission electron microscopy (TEM) and UV–vis spectroscopy. The underlying dendrite growth mechanism was then proposed in the context of the Directed Electrochemical Nanowires Assembly (DENA) models. Owing to the unscreened voltage dropping in the electrolyte bulk, electromigration dominates the species flux process, and cations tend to accumulate in areas with strong electricmore » field intensity, such as electrode edges. Moreover, Faradaic AC-electro-osmosis (ACEO) flow could increase the effective diffusion layer thickness in these areas during the electrochemical reaction, and leads to dendrite growth. Further Micro-Raman observations illustrated that the Au/Ag bimetallic dendrites exhibited pronounced surface-enhanced Raman scattering (SERS) activity, using 4-mercaptopyridine (4-MP) as model molecules.« less

  4. Application of Multi-Objective Human Learning Optimization Method to Solve AC/DC Multi-Objective Optimal Power Flow Problem

    NASA Astrophysics Data System (ADS)

    Cao, Jia; Yan, Zheng; He, Guangyu

    2016-06-01

    This paper introduces an efficient algorithm, multi-objective human learning optimization method (MOHLO), to solve AC/DC multi-objective optimal power flow problem (MOPF). Firstly, the model of AC/DC MOPF including wind farms is constructed, where includes three objective functions, operating cost, power loss, and pollutant emission. Combining the non-dominated sorting technique and the crowding distance index, the MOHLO method can be derived, which involves individual learning operator, social learning operator, random exploration learning operator and adaptive strategies. Both the proposed MOHLO method and non-dominated sorting genetic algorithm II (NSGAII) are tested on an improved IEEE 30-bus AC/DC hybrid system. Simulation results show that MOHLO method has excellent search efficiency and the powerful ability of searching optimal. Above all, MOHLO method can obtain more complete pareto front than that by NSGAII method. However, how to choose the optimal solution from pareto front depends mainly on the decision makers who stand from the economic point of view or from the energy saving and emission reduction point of view.

  5. Schlieren optical visualization for transient EHD induced flow in a stratified dielectric liquid under gas-phase ac corona discharges

    NASA Astrophysics Data System (ADS)

    Ohyama, R.; Inoue, K.; Chang, J. S.

    2007-01-01

    A flow pattern characterization of electrohydrodynamically (EHD) induced flow phenomena of a stratified dielectric fluid situated in an ac corona discharge field is conducted by a Schlieren optical system. A high voltage application to a needle-plate electrode arrangement in gas-phase normally initiates a conductive type EHD gas flow. Although the EHD gas flow motion initiated from the corona discharge electrode has been well known as corona wind, no comprehensive study has been conducted for an EHD fluid flow motion of the stratified dielectric liquid that is exposed to the gas-phase ac corona discharge. The experimentally observed result clearly presents the liquid-phase EHD flow phenomenon induced from the gas-phase EHD flow via an interfacial momentum transfer. The flow phenomenon is also discussed in terms of the gas-phase EHD number under the reduced gas pressure (reduced interfacial momentum transfer) conditions.

  6. Three-Phase AC Optimal Power Flow Based Distribution Locational Marginal Price: Preprint

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

    Yang, Rui; Zhang, Yingchen

    2017-05-17

    Designing market mechanisms for electricity distribution systems has been a hot topic due to the increased presence of smart loads and distributed energy resources (DERs) in distribution systems. The distribution locational marginal pricing (DLMP) methodology is one of the real-time pricing methods to enable such market mechanisms and provide economic incentives to active market participants. Determining the DLMP is challenging due to high power losses, the voltage volatility, and the phase imbalance in distribution systems. Existing DC Optimal Power Flow (OPF) approaches are unable to model power losses and the reactive power, while single-phase AC OPF methods cannot capture themore » phase imbalance. To address these challenges, in this paper, a three-phase AC OPF based approach is developed to define and calculate DLMP accurately. The DLMP is modeled as the marginal cost to serve an incremental unit of demand at a specific phase at a certain bus, and is calculated using the Lagrange multipliers in the three-phase AC OPF formulation. Extensive case studies have been conducted to understand the impact of system losses and the phase imbalance on DLMPs as well as the potential benefits of flexible resources.« less

  7. System and component design and test of a 10 hp, 18,000 rpm AC dynamometer utilizing a high frequency AC voltage link, part 1

    NASA Technical Reports Server (NTRS)

    Lipo, Thomas A.; Alan, Irfan

    1991-01-01

    Hard and soft switching test results conducted with one of the samples of first generation MOS-controlled thyristor (MCTs) and similar test results with several different samples of second generation MCT's are reported. A simple chopper circuit is used to investigate the basic switching characteristics of MCT under hard switching and various types of resonant circuits are used to determine soft switching characteristics of MCT under both zero voltage and zero current switching. Next, operation principles of a pulse density modulated converter (PDMC) for three phase (3F) to 3F two-step power conversion via parallel resonant high frequency (HF) AC link are reviewed. The details for the selection of power switches and other power components required for the construction of the power circuit for the second generation 3F to 3F converter system are discussed. The problems encountered in the first generation system are considered. Design and performance of the first generation 3F to 3F power converter system and field oriented induction moter drive based upon a 3 kVA, 20 kHz parallel resonant HF AC link are described. Low harmonic current at the input and output, unity power factor operation of input, and bidirectional flow capability of the system are shown via both computer and experimental results. The work completed on the construction and testing of the second generation converter and field oriented induction motor drive based upon specifications for a 10 hp squirrel cage dynamometer and a 20 kHz parallel resonant HF AC link is discussed. The induction machine is designed to deliver 10 hp or 7.46 kW when operated as an AC-dynamo with power fed back to the source through the converter. Results presented reveal that the proposed power level requires additional energy storage elements to overcome difficulties with a peak link voltage variation problem that limits reaching to the desired power level. The power level test of the second generation converter after the

  8. Assessment of three AC electroosmotic flow protocols for mixing in microfluidic channel.

    PubMed

    Chen, Jia-Kun; Weng, Chi-Neng; Yang, Ruey-Jen

    2009-05-07

    This study performs an experimental investigation into the micromixer capabilities of three different protocols of AC electroosmotic flow (AC EOF), namely capacitive charging (CC), Faradaic charging (FC) and asymmetric polarization (AP). The results reveal that the vortices generated by the FC protocol (the frequency is around 50-350 Hz) are stronger than those induced by the CC protocol (the frequency is higher than 350 Hz), and therefore provide an improved mixing effect. However, in the FC protocol, the frequency of the external AC voltage must be carefully controlled to avoid damaging electrodes as a result of Faradaic reactions. The experimental results indicate that the AP polarization effect (the applied voltage and frequency are V(1) = 1 V(pp) and V(2) = 20 V(pp)/5 kHz) induces more powerful vortices than either the CC protocol or the FC protocol, and therefore yields a better mixing performance. Two AP-based micromixers are fabricated with symmetric and asymmetric electrode configurations, respectively. The mixing indices achieved by the two devices after an elapsed time of 60 seconds are found to be 56.49 % and 71.77 %, respectively. This result shows that of the two devices, an asymmetric electrode configuration represents a more suitable choice for micromixer in microfluidic devices.

  9. Investigation of pumping mechanism for non-Newtonian blood flow with AC electrothermal forces in a microchannel by hybrid boundary element method and immersed boundary-lattice Boltzmann method.

    PubMed

    Ren, Qinlong

    2018-02-10

    Efficient pumping of blood flow in a microfluidic device is essential for rapid detection of bacterial bloodstream infections (BSI) using alternating current (AC) electrokinetics. Compared with AC electro-osmosis (ACEO) phenomenon, the advantage of AC electrothermal (ACET) mechanism is its capability of pumping biofluids with high electrical conductivities at a relatively high AC voltage frequency. In the current work, the microfluidic pumping of non-Newtonian blood flow using ACET forces is investigated in detail by modeling its multi-physics process with hybrid boundary element method (BEM) and immersed boundary-lattice Boltzmann method (IB-LBM). The Carreau-Yasuda model is used to simulate the realistic rheological behavior of blood flow. The ACET pumping efficiency of blood flow is studied in terms of different AC voltage magnitudes and frequencies, thermal boundary conditions of electrodes, electrode configurations, channel height, and the channel length per electrode pair. Besides, the effect of rheological behavior on the blood flow velocity is theoretically analyzed by comparing with the Newtonian fluid flow using scaling law analysis under the same physical conditions. The results indicate that the rheological behavior of blood flow and its frequency-dependent dielectric property make the pumping phenomenon of blood flow different from that of the common Newtonian aqueous solutions. It is also demonstrated that using a thermally insulated electrode could enhance the pumping efficiency dramatically. Besides, the results conclude that increasing the AC voltage magnitude is a more economical pumping approach than adding the number of electrodes with the same energy consumption when the Joule heating effect is acceptable. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  10. Gene delivery by microfluidic flow-through electroporation based on constant DC and AC field.

    PubMed

    Geng, Tao; Zhan, Yihong; Lu, Chang

    2012-01-01

    Electroporation is one of the most widely used physical methods to deliver exogenous nucleic acids into cells with high efficiency and low toxicity. Conventional electroporation systems typically require expensive pulse generators to provide short electrical pulses at high voltage. In this work, we demonstrate a flow-through electroporation method for continuous transfection of cells based on disposable chips, a syringe pump, and a low-cost power supply that provides a constant voltage. We successfully transfect cells using either DC or AC voltage with high flow rates (ranging from 40 µl/min to 20 ml/min) and high efficiency (up to 75%). We also enable the entire cell membrane to be uniformly permeabilized and dramatically improve gene delivery by inducing complex migrations of cells during the flow.

  11. Transport of particles and microorganisms in microfluidic channels using rectified ac electro-osmotic flow

    PubMed Central

    Wu, Wen-I; Selvaganapathy, P. Ravi; Ching, Chan Y.

    2011-01-01

    A new method is demonstrated to transport particles, cells, and other microorganisms using rectified ac electro-osmotic flows in open microchannels. The rectified flow is obtained by synchronous zeta potential modulation with the driving potential in the microchannel. Experiments were conducted to transport both neutral, charged particles, and microorganisms of various sizes. A maximum speed of 50 μm∕s was obtained for 8 μm polystyrene beads, without any electrolysis, using a symmetrical square waveform driving electric field of 5 V∕mm at 10 Hz and a 360 V gate potential with its polarity synchronized with the driving potential (phase lag=0°). PMID:21522497

  12. FLUIDIC AC AMPLIFIERS.

    DTIC Science & Technology

    Several fluidic tuned AC Amplifiers were designed and tested. Interstage tuning and feedback designs are considered. Good results were obtained...corresponding Q’s as high as 12. Element designs and test results of one, two, and three stage amplifiers are presented. AC Modulated Carrier Systems

  13. Testing of a First Order AC Magnetic Susceptometer

    NASA Astrophysics Data System (ADS)

    Fukuda, Ryan; Sunny, Smitha; Ho, Pei-Chun

    2011-11-01

    A first-order AC magnetic susceptometer has been constructed and tested to find the magnetic response of strongly correlated electron materials. The instrument works by using a primary coil to apply a small AC magnetic field of .104 Oe to a sample with a cylindrical coil space of length .635 cm and diameter .355 cm. A lock-in amplifier is used to monitor the induced voltage from a set of secondary coils. By coupling a temperature-controlled system with this instrument, the change in the magnetic signal with respect to temperature is measured. Monitoring the signal changes may indicate the temperature that causes the material to transition to either a ferromagnetic, anti-ferromagnetic, or superconducting state. A 122.47 mg Gd polycrystal was used to test our susceptometer. The data qualitatively agrees with the previous results of magnetization vs. temperature of Gd single crystals by Nigh et al. [1]: there is a steep increase in the pick-up signal at 300 K where Gd becomes ferromagnetic and a peak at 210 K [1]. This susceptometer will be used for our future investigation of magnetic properties of rare earth compounds and nanoparticles in the temperature range of 10 K to 300 K. [4pt] [1] H. E. Nigh, S. Legvold, and F. H. Spedding, Physical Review 132, 1092 (1963)

  14. An AC electroosmotic micropump for circular chromatographic applications.

    PubMed

    Debesset, S; Hayden, C J; Dalton, C; Eijkel, J C T; Manz, A

    2004-08-01

    Flow rates of up to 50 microm s(-1) have been successfully achieved in a closed-loop channel using an AC electroosmotic pump. The AC electroosmotic pump is made of an interdigitated array of unequal width electrodes located at the bottom of a channel, with an AC voltage applied between the small and the large electrodes. The flow rate was found to increase linearly with the applied voltage and to decrease linearly with the applied frequency. The pump is expected to be suitable for circular chromatography for the following reasons: the driving forces are distributed over the channel length and the pumping direction is set by the direction of the interdigitated electrodes. Pumping in a closed-loop channel can be achieved by arranging the electrode pattern in a circle. In addition the inherent working principle of AC electroosmotic pumping enables the independent optimisation of the channel height or the flow velocity.

  15. Spectral and Power Stability Tests of Deep UV LEDs for AC Charge Management

    NASA Astrophysics Data System (ADS)

    Sun, Ke-Xun; Higuchi, Sei; Goh, Allex; Allard, Brett; Gill, Dale; Buchman, Saps; Byer, Robert

    2006-11-01

    Deep ultraviolet (UV) LEDs have recently been used in AC charge management experiments to support gravitational reference sensors for future space missions. The UV LED based charge management system offers compact size, light weight, and low power consumption compared to plasma sources. The AC charge management technique, which is enabled by easy modulation of UV LED output, achieves higher dynamic range for charge control. Further, the high modulation frequency, which is out of the gravitational wave detection band, reduces disturbances to the proof mass. However, there is a need to test and possibly improve the lifetime of UV LEDs, which were developed only a year ago. We have initiated a series of spectral and power stability tests for UV LEDs and designed experiments according to the requirements of AC charge management. We operate UV LEDs with a modulated current drive and maintain the operating temperature at 22 °C,28 similar to the LISA spacecraft working condition. The testing procedures involve measuring the baseline spectral shape and output power level prior to the beginning of the tests and then re-measuring the same quantities periodically. As of the date of submission (August 28th, 2006), we have operated a UV LED for more than 2,700 hours.

  16. 40 CFR 86.167-17 - AC17 Air Conditioning Emissions Test Procedure.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... tolerances (such as may occur during gear changes) are acceptable provided they occur for less than 2 seconds... setting changed to “outside air.” (l) Test procedure. The AC17 air conditioning test is composed of the..., interior volume, climate control system type and characteristics, refrigerant used, compressor type, and...

  17. Using nonlinear ac electrokinetics vortex flow to enhance catalytic activities of sol-gel encapsulated trypsin in microfluidic devices

    PubMed Central

    Wang, Shau-Chun; Chen, Hsiao-Ping; Lai, Yi-Wen; Chau, Lai-Kwan; Chuang, Yu-Chun; Chen, Yi-Jie

    2007-01-01

    A novel microstirring strategy is applied to accelerate the digestion rate of the substrate Nα-benzoyl-L-arginine-4-nitroanilide (L-BAPA) catalyzed by sol-gel encapsulated trypsin. We use an ac nonlinear electrokinetic vortex flow to stir the solution in a microfluidic reaction chamber to reduce the diffusion length between the immobilized enzyme and substrate in the solution. High-intensity nonlinear electroosmotic microvortices, with angular speeds in excess of 1 cm∕s, are generated around a small (∼1.2 mm) conductive ion exchange granule when ac electric fields (133 V∕cm) are applied across a miniature chamber smaller than 10 μl. Coupling between these microvortices and the on-and-off electrophoretic motion of the granule in low frequency (0.1 Hz) ac fields produces chaotic stream lines to stir substrate molecules sufficiently. We demonstrate that, within a 5-min digestion period, the catalytic reaction rate of immobilized trypsin increases almost 30-fold with adequate reproducibility (15%) due to sufficient stirring action through the introduction of the nonlinear electrokinetic vortices. In contrast, low-frequency ac electroosmotic flow without the granule, provides limited stirring action and increases the reaction rate approximately ninefold with barely acceptable reproducibility (30%). Dye molecules are used to characterize the increases in solute diffusivity in the reaction reservoir in which sol-gel particles are placed, with and without the presence of granule, and compared with the static case. The solute diffusivity enhancement data show respective increases of ∼30 and ∼8 times, with and without the presence of granule. These numbers are consistent with the ratios of the enhanced reaction rate. PMID:19693360

  18. Using nonlinear ac electrokinetics vortex flow to enhance catalytic activities of sol-gel encapsulated trypsin in microfluidic devices.

    PubMed

    Wang, Shau-Chun; Chen, Hsiao-Ping; Lai, Yi-Wen; Chau, Lai-Kwan; Chuang, Yu-Chun; Chen, Yi-Jie

    2007-09-04

    A novel microstirring strategy is applied to accelerate the digestion rate of the substrate N(alpha)-benzoyl-L-arginine-4-nitroanilide (L-BAPA) catalyzed by sol-gel encapsulated trypsin. We use an ac nonlinear electrokinetic vortex flow to stir the solution in a microfluidic reaction chamber to reduce the diffusion length between the immobilized enzyme and substrate in the solution. High-intensity nonlinear electroosmotic microvortices, with angular speeds in excess of 1 cms, are generated around a small ( approximately 1.2 mm) conductive ion exchange granule when ac electric fields (133 Vcm) are applied across a miniature chamber smaller than 10 mul. Coupling between these microvortices and the on-and-off electrophoretic motion of the granule in low frequency (0.1 Hz) ac fields produces chaotic stream lines to stir substrate molecules sufficiently. We demonstrate that, within a 5-min digestion period, the catalytic reaction rate of immobilized trypsin increases almost 30-fold with adequate reproducibility (15%) due to sufficient stirring action through the introduction of the nonlinear electrokinetic vortices. In contrast, low-frequency ac electroosmotic flow without the granule, provides limited stirring action and increases the reaction rate approximately ninefold with barely acceptable reproducibility (30%). Dye molecules are used to characterize the increases in solute diffusivity in the reaction reservoir in which sol-gel particles are placed, with and without the presence of granule, and compared with the static case. The solute diffusivity enhancement data show respective increases of approximately 30 and approximately 8 times, with and without the presence of granule. These numbers are consistent with the ratios of the enhanced reaction rate.

  19. Performance trends of rehabilitated AC pavements

    DOT National Transportation Integrated Search

    2000-10-01

    The General Pavement Study (GPS) 6 experiment, "AC Overlay of AC Pavements," involves pavement test sections where an asphalt concrete (AC) overlay was placed on an existing AC pavement. This TechBrief summarizes the results of a study of the GPS-6 e...

  20. 40 CFR 86.162-00 - Approval of alternative air conditioning test simulations and descriptions of AC1 and AC2.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... power requirements to roadload dynamometer requirements. AC2 simulates, in standard test cell ambient...)(i) (A) and (B) are replaced with 76 °F and 50 grains of water/pound of dry air and the solar heat...)(5)(i) (A) and (B) are replaced with 76 °F and 50 grains of water/pound of dry air and the solar heat...

  1. 40 CFR 86.162-00 - Approval of alternative air conditioning test simulations and descriptions of AC1 and AC2.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... power requirements to roadload dynamometer requirements. AC2 simulates, in standard test cell ambient...)(i) (A) and (B) are replaced with 76 °F and 50 grains of water/pound of dry air and the solar heat...)(5)(i) (A) and (B) are replaced with 76 °F and 50 grains of water/pound of dry air and the solar heat...

  2. Characterization on performance of micromixer using DC-biased AC electroosmosis

    NASA Astrophysics Data System (ADS)

    Park, Bi-O.; Song, Simon

    2010-11-01

    An active micromixer using DC-biased AC-Electroosmosis (ACEO) is investigated to figure out the effects of design parameters on the mixing performance. The mixer consists of a straight microchannel, with a cross section of 60 x 100 μm, and gold electrode pairs fabricated in the microchannel. The design parameters include the number of electrode pairs, flow rate, DC-biased voltage, AC voltage and AC frequency. First, we found that a mixing index became 80% 100 μm downstream of a single electrode pair with a length of 2 mm when applying a 25Vpp, 2.0 VDC, 100 kHz sine signal to the electrodes. With decreasing AC frequency, the mixing index is affected little. But the mixing index significantly increases with increasing either DC-biased voltage or AC voltage. Also, we were able to increase the mixing index up to 90% by introducing alternating vortices with multiple electrode pairs. Finally, we discovered that the mixing index decreases as the flow rate increases in the microchannel, and there is an optimal number of electrode pairs with respect to a flow rate. Detailed quantitative measurement results will be presented at the meeting.

  3. Hybrid flow control of a transport truck side-mirror using AC-DBD plasma actuated guide vane

    NASA Astrophysics Data System (ADS)

    Michelis, Theodoros; Kotsonis, Marios

    2014-11-01

    A wind-tunnel study is conducted towards hybrid flow control of a full-scale transport truck side-mirror (Re = 4 ×105) . The mirror is mounted on a structure that models the truck cabin. PIV measurements are performed at a range of velocities from 15 to 25 m/s and from leeward to windward angles of -5° to +5° . A slim guide vane of 6cm chord is employed along the span of the hub of the mirror for redirecting high momentum flow towards the wake region. Separation from the leading edge of the guide vane is reduced or eliminated by means of AC-DBD plasma actuator, operating at voltage of 35 kV peak-to-peak and frequency of 200 Hz. Time-averaged velocity fields are obtained at the centre of the mirror for three scenarios: a) reference case lacking any control elements; b) guide vane only and c) combination of the guide vane and the AC-DBD. The comparison of cases demonstrates that at 25 m/s windward conditions (-5°) the guide vane is capable of increasing momentum (+20%) in the wake of the mirror with additional improvement when plasma actuation is applied (+21%). In contrast, at leeward conditions (+5°) , the guide vane reduces momentum (-20%), though with actuation an increase is observed (+5%). Total recovered momentum is 25%.

  4. AC electrified jets in a flow-focusing device: Jet length scaling

    PubMed Central

    García-Sánchez, Pablo; Alzaga-Gimeno, Javier; Baret, Jean-Christophe

    2016-01-01

    We use a microfluidic flow-focusing device with integrated electrodes for controlling the production of water-in-oil drops. In a previous work, we reported that very long jets can be formed upon application of AC fields. We now study in detail the appearance of the long jets as a function of the electrical parameters, i.e., water conductivity, signal frequency, and voltage amplitude. For intermediate frequencies, we find a threshold voltage above which the jet length rapidly increases. Interestingly, this abrupt transition vanishes for high frequencies of the signal and the jet length grows smoothly with voltage. For frequencies below a threshold value, we previously reported a transition from a well-behaved uniform jet to highly unstable liquid structures in which axisymmetry is lost rather abruptly. These liquid filaments eventually break into droplets of different sizes. In this work, we characterize this transition with a diagram as a function of voltage and liquid conductivity. The electrical response of the long jets was studied via a distributed element circuit model. The model allows us to estimate the electric potential at the tip of the jet revealing that, for any combination of the electrical parameters, the breakup of the jet occurs at a critical value of this potential. We show that this voltage is around 550 V for our device geometry and choice of flow rates. PMID:27375826

  5. AC electrified jets in a flow-focusing device: Jet length scaling.

    PubMed

    Castro-Hernández, Elena; García-Sánchez, Pablo; Alzaga-Gimeno, Javier; Tan, Say Hwa; Baret, Jean-Christophe; Ramos, Antonio

    2016-07-01

    We use a microfluidic flow-focusing device with integrated electrodes for controlling the production of water-in-oil drops. In a previous work, we reported that very long jets can be formed upon application of AC fields. We now study in detail the appearance of the long jets as a function of the electrical parameters, i.e., water conductivity, signal frequency, and voltage amplitude. For intermediate frequencies, we find a threshold voltage above which the jet length rapidly increases. Interestingly, this abrupt transition vanishes for high frequencies of the signal and the jet length grows smoothly with voltage. For frequencies below a threshold value, we previously reported a transition from a well-behaved uniform jet to highly unstable liquid structures in which axisymmetry is lost rather abruptly. These liquid filaments eventually break into droplets of different sizes. In this work, we characterize this transition with a diagram as a function of voltage and liquid conductivity. The electrical response of the long jets was studied via a distributed element circuit model. The model allows us to estimate the electric potential at the tip of the jet revealing that, for any combination of the electrical parameters, the breakup of the jet occurs at a critical value of this potential. We show that this voltage is around 550 V for our device geometry and choice of flow rates.

  6. ACS Science Data Buffer Check/Self-Tests for CS Buffer RAM and MIE RAM

    NASA Astrophysics Data System (ADS)

    Balzano, V.

    2001-07-01

    The ACS Science Buffer RAM is checked for bit flips during SAA passages. This is followed by a Control Section {CS} self-test consisting of writing/reading a specified bit pattern from each memory location in Buffer RAM and a similar test for MIE RAM. The MIE must be placed in BOOT mode for its self-test. The CS Buffer RAM self-test as well as the bit flip tests are all done with the CS in Operate.

  7. ACS Science Data Buffer Check/Self-Tests for CS Buffer RAM and MIE RAM

    NASA Astrophysics Data System (ADS)

    Welty, Alan

    2005-07-01

    The ACS Science Buffer RAM is checked for bit flips during SAA passages. Thisis followed by a Control Section {CS} self-test consisting of writing/reading a specified bit pattern from each memory location in Buffer RAM and a similar test for MIE RAM. The MIE must be placed in BOOT mode for its self-test. The CS Buffer RAM self-test as well as the bit flip tests are all done with the CS in Operate.

  8. Method and system for an on-chip AC self-test controller

    DOEpatents

    Flanagan, John D [Rhinebeck, NY; Herring, Jay R [Poughkeepsie, NY; Lo, Tin-Chee [Fishkill, NY

    2008-09-30

    A method and system for performing AC self-test on an integrated circuit that includes a system clock for use during normal operation are provided. The method includes applying a long data capture pulse to a first test register in response to the system clock, applying an at speed data launch pulse to the first test register in response to the system clock, inputting the data from the first register to a logic path in response to applying the at speed data launch pulse to the first test register, applying an at speed data capture pulse to a second test register in response to the system clock, inputting the logic path output to the second test register in response to applying the at speed data capture pulse to the second test register, and applying a long data launch pulse to the second test register in response to the system clock.

  9. Method and system for an on-chip AC self-test controller

    DOEpatents

    Flanagan, John D.; Herring, Jay R.; Lo, Tin-Chee

    2006-06-06

    A method for performing AC self-test on an integrated circuit, including a system clock for use during normal operation. The method includes applying a long data capture pulse to a first test register in response to the system clock, and further applying at an speed data launch pulse to the first test register in response to the system clock. Inputting the data from the first register to a logic path in response to applying the at speed data launch pulse to the first test register. Applying at speed data capture pulse to a second test register in response to the system clock. Inputting the output from the logic path to the second test register in response to applying the at speed data capture pulse to the second register. Applying a long data launch pulse to the second test register in response to the system clock.

  10. Analysis of Electrokinetic Mixing Using AC Electric Field and Patchwise Surface Heterogeneities

    NASA Astrophysics Data System (ADS)

    Luo, Win-Jet; Yarn, Kao-Feng; Hsu, Shou-Ping

    2007-04-01

    In this paper, the authors investigate the use of an applied AC electric field and microchannel surface heterogeneities to carry out the microfluidic mixing of two-dimensional, time-dependent electroosmotic flows. The time-dependent flow fields within the microchannel are simulated using the backwards-Euler time-stepping numerical method. The mixing efficiencies obtained in microchannels with two different patchwise surface heterogeneity patterns are investigated. In general, the results show that the application of an AC electric field significantly reduces the required mixing length compared with the use of a DC electric field. Furthermore, the presence of oppositely charged surface heterogeneities on the microchannel walls results in the formation of localized flow circulation regions within the bulk flow. These circulation regions grow and decay periodically in accordance with the periodic variation of the AC electric field intensity and provide an effective means of enhancing species mixing in the microchannel. Consequently, the use of an AC electric field together with patchwise surface heterogeneities permits a significant reduction in both the mixing channel length and the retention time required to attain a homogeneous solution.

  11. AC Electroosmotic Pumping in Nanofluidic Funnels.

    PubMed

    Kneller, Andrew R; Haywood, Daniel G; Jacobson, Stephen C

    2016-06-21

    We report efficient pumping of fluids through nanofluidic funnels when a symmetric AC waveform is applied. The asymmetric geometry of the nanofluidic funnel induces not only ion current rectification but also electroosmotic flow rectification. In the base-to-tip direction, the funnel exhibits a lower ion conductance and a higher electroosmotic flow velocity, whereas, in the tip-to-base direction, the funnel has a higher ion conductance and a lower electroosmotic flow velocity. Consequently, symmetric AC waveforms easily pump fluid through the nanofunnels over a range of frequencies, e.g., 5 Hz to 5 kHz. In our experiments, the nanofunnels were milled into glass substrates with a focused ion beam (FIB) instrument, and the funnel design had a constant 5° taper with aspect ratios (funnel tip width to funnel depth) of 0.1 to 1.0. We tracked ion current rectification by current-voltage (I-V) response and electroosmotic flow rectification by transport of a zwitterionic fluorescent probe. Rectification of ion current and electroosmotic flow increased with increasing electric field applied to the nanofunnel. Our results support three-dimensional simulations of ion transport and electroosmotic transport through nanofunnels, which suggest the asymmetric electroosmotic transport stems from an induced pressure at the junction of the nanochannel and nanofunnel tip.

  12. Dynamic power flow controllers

    DOEpatents

    Divan, Deepakraj M.; Prasai, Anish

    2017-03-07

    Dynamic power flow controllers are provided. A dynamic power flow controller may comprise a transformer and a power converter. The power converter is subject to low voltage stresses and not floated at line voltage. In addition, the power converter is rated at a fraction of the total power controlled. A dynamic power flow controller controls both the real and the reactive power flow between two AC sources having the same frequency. A dynamic power flow controller inserts a voltage with controllable magnitude and phase between two AC sources; thereby effecting control of active and reactive power flows between two AC sources.

  13. Transient electroosmotic flow induced by DC or AC electric fields in a curved microtube.

    PubMed

    Luo, W-J

    2004-10-15

    This study investigates transient electroosmotic flow in a rectangular curved microtube in which the fluid is driven by the application of an external DC or AC electric field. The resultant flow-field evolutions within the microtube are simulated using the backwards-Euler time-stepping numerical method to clarify the relationship between the changes in the axial-flow velocity and the intensity of the applied electric field. When the electric field is initially applied or varies, the fluid within the double layer responds virtually immediately, and the axial velocity within the double layer tends to follow the varying intensity of the applied electric field. The greatest net charge density exists at the corners of the microtube as a result of the overlapping electrical double layers of the two walls. It results in local maximum or minimum axial velocities in the corners during increasing or decreasing applied electric field intensity in either the positive or negative direction. As the fluid within the double layer starts to move, the bulk fluid is gradually dragged into motion through the diffusion of momentum from the double layer. A finite time is required for the full momentum of the double layer to diffuse to the bulk fluid; hence, a certain phase shift between the applied electric field and the flow response is inevitable. The patterns of the axial velocity contours during the transient evolution are investigated in this study. It is found that these patterns are determined by the efficiency of momentum diffusion from the double layer to the central region of the microtube.

  14. Regulation of Dynamical Systems to Optimal Solutions of Semidefinite Programs: Algorithms and Applications to AC Optimal Power Flow

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

    Dall'Anese, Emiliano; Dhople, Sairaj V.; Giannakis, Georgios B.

    2015-07-01

    This paper considers a collection of networked nonlinear dynamical systems, and addresses the synthesis of feedback controllers that seek optimal operating points corresponding to the solution of pertinent network-wide optimization problems. Particular emphasis is placed on the solution of semidefinite programs (SDPs). The design of the feedback controller is grounded on a dual e-subgradient approach, with the dual iterates utilized to dynamically update the dynamical-system reference signals. Global convergence is guaranteed for diminishing stepsize rules, even when the reference inputs are updated at a faster rate than the dynamical-system settling time. The application of the proposed framework to the controlmore » of power-electronic inverters in AC distribution systems is discussed. The objective is to bridge the time-scale separation between real-time inverter control and network-wide optimization. Optimization objectives assume the form of SDP relaxations of prototypical AC optimal power flow problems.« less

  15. Max Launch Abort System (MLAS) Pad Abort Test Vehicle (PATV) II Attitude Control System (ACS) Integration and Pressurization Subsystem Dynamic Random Vibration Analysis

    NASA Technical Reports Server (NTRS)

    Ekrami, Yasamin; Cook, Joseph S.

    2011-01-01

    In order to mitigate catastrophic failures on future generation space vehicles, engineers at the National Aeronautics and Space Administration have begun to integrate a novel crew abort systems that could pull a crew module away in case of an emergency at the launch pad or during ascent. The Max Launch Abort System (MLAS) is a recent test vehicle that was designed as an alternative to the baseline Orion Launch Abort System (LAS) to demonstrate the performance of a "tower-less" LAS configuration under abort conditions. The MLAS II test vehicle will execute a propulsive coast stabilization maneuver during abort to control the vehicles trajectory and thrust. To accomplish this, the spacecraft will integrate an Attitude Control System (ACS) with eight hypergolic monomethyl hydrazine liquid propulsion engines that are capable of operating in a quick pulsing mode. Two main elements of the ACS include a propellant distribution subsystem and a pressurization subsystem to regulate the flow of pressurized gas to the propellant tanks and the engines. The CAD assembly of the Attitude Control System (ACS) was configured and integrated into the Launch Abort Vehicle (LAV) design. A dynamic random vibration analysis was conducted on the Main Propulsion System (MPS) helium pressurization panels to assess the response of the panel and its components under increased gravitational acceleration loads during flight. The results indicated that the panels fundamental and natural frequencies were farther from the maximum Acceleration Spectral Density (ASD) vibrations which were in the range of 150-300 Hz. These values will direct how the components will be packaged in the vehicle to reduce the effects high gravitational loads.

  16. THE EFFECT OF WATER (VAPOR-PHASE) AND CARBON ON ELEMENTAL MERCURY REMOVAL IN A FLOW REACTOR

    EPA Science Inventory

    The paper gives results of studying the effect of vapor-phase moisture on elemental mercury (Hgo) removal by activated carbon (AC) in a flow reactor. tests involved injecting AC into both a dry and a 4% moisture nitrogen (N2) /Hgo gas stream. A bituminous-coal-based AC (Calgon WP...

  17. LADEE Propulsion System Cold Flow Test

    NASA Technical Reports Server (NTRS)

    Williams, Jonathan Hunter; Chapman, Jack M.; Trinh, Hau, P.; Bell, James H.

    2013-01-01

    Lunar Atmosphere and Dust Environment Explorer (LADEE) is a NASA mission that will orbit the Moon. Its main objective is to characterize the atmosphere and lunar dust environment. The spacecraft development is being led by NASA Ames Research Center and scheduled for launch in 2013. The LADEE spacecraft will be operated with a bi-propellant hypergolic propulsion system using MMH and NTO as the fuel and oxidizer, respectively. The propulsion system utilizes flight-proven hardware on major components. The propulsion layout is composed of one 100-lbf main thruster and four 5-lbf RCS thrusters. The propellants are stored in four tanks (two parallel-connected tanks per propellant component). The propellants will be pressurized by regulated helium. A simulated propulsion system has been built for conducting cold flow test series to characterize the transient fluid flow of the propulsion system feed lines and to verify the critical operation modes, such as system priming, waterhammer, and crucial mission duty cycles. Propellant drainage differential between propellant tanks will also be assessed. Since the oxidizer feed line system has a higher flow demand than the fuel system does, the cold flow test focuses on the oxidizer system. The objective of the cold flow test is to simulate the LADEE propulsion fluid flow operation through water cold flow test and to obtain data for anchoring analytical models. The models will be used to predict the transient and steady state flow behaviors in the actual flight operations. The test activities, including the simulated propulsion test article, cold flow test, and analytical modeling, are being performed at NASA Marshall Space Flight Center. At the time of the abstract submission, the test article checkout is being performed. The test series will be completed by November, 2012

  18. Resonant AC power system proof-of-concept test program, volume 2, appendix 1

    NASA Technical Reports Server (NTRS)

    1986-01-01

    This report contains two volumes. The main text (Volume 1) summarizes the tests results and gives a detailed discussion of the response of three early, first generation configurations of ac power system IRAD breadboards to the contracted tests imposed on them. It explains photographs, measurements, and data calculations, as well as any observed anomalies or lessons learned. This volume (No 2, Appendix 1, Test Results and Data), published under separate cover, includes all of the data taken on the 1.0 kW single-phase; 5.0 kW three-phase; and 25.0-kW three-phase system breadboards. The format of this data is raw, i.e., it is a direct copy of the data sheets for the test data notebook.

  19. AC electroosmotic micromixer for chemical processing in a microchannel.

    PubMed

    Sasaki, Naoki; Kitamori, Takehiko; Kim, Haeng-Boo

    2006-04-01

    A rapid micromixer of fluids in a microchannel is presented. The mixer uses AC electroosmotic flow, which is induced by applying an AC voltage to a pair of coplanar meandering electrodes configured in parallel to the channel. To demonstrate performance of the mixer, dilution experiments were conducted using a dye solution in a channel of 120 microm width. Rapid mixing was observed for flow velocity up to 12 mm s(-1). The mixing time was 0.18 s, which was 20-fold faster than that of diffusional mixing without an additional mixing mechanism. Compared with the performance of reported micromixers, the present mixer worked with a shorter mixing length, particularly at low Peclet numbers (Pe < 2 x 10(3)).

  20. System and method for determining stator winding resistance in an AC motor

    DOEpatents

    Lu, Bin [Kenosha, WI; Habetler, Thomas G [Snellville, GA; Zhang, Pinjia [Atlanta, GA; Theisen, Peter J [West Bend, WI

    2011-05-31

    A system and method for determining stator winding resistance in an AC motor is disclosed. The system includes a circuit having an input connectable to an AC source and an output connectable to an input terminal of an AC motor. The circuit includes at least one contactor and at least one switch to control current flow and terminal voltages in the AC motor. The system also includes a controller connected to the circuit and configured to modify a switching time of the at least one switch to create a DC component in an output of the system corresponding to an input to the AC motor and determine a stator winding resistance of the AC motor based on the injected DC component of the voltage and current.

  1. Resource Prospector Propulsion Cold Flow Test

    NASA Technical Reports Server (NTRS)

    Williams, Hunter; Pederson, Kevin; Dervan, Melanie; Holt, Kimberly; Jernigan, Frankie; Trinh, Huu; Flores, Sam

    2014-01-01

    For the past year, NASA Marshall Space Flight Center and Johnson Space Center have been working on a government version of a lunar lander design for the Resource Prospector Mission. A propulsion cold flow test system, representing an early flight design of the propulsion system, has been fabricated. The primary objective of the cold flow test is to simulate the Resource Prospector propulsion system operation through water flow testing and obtain data for anchoring analytical models. This effort will also provide an opportunity to develop a propulsion system mockup to examine hardware integration to a flight structure. This paper will report the work progress of the propulsion cold flow test system development and test preparation. At the time this paper is written, the initial waterhammer testing is underway. The initial assessment of the test data suggests that the results are as expected and have a similar trend with the pretest prediction. The test results will be reported in a future conference.

  2. Frequency tuning allows flow direction control in microfluidic networks with passive features.

    PubMed

    Jain, Rahil; Lutz, Barry

    2017-05-02

    Frequency tuning has emerged as an attractive alternative to conventional pumping techniques in microfluidics. Oscillating (AC) flow driven through a passive valve can be rectified to create steady (DC) flow, and tuning the excitation frequency to the characteristic (resonance) frequency of the underlying microfluidic network allows control of flow magnitude using simple hardware, such as an on-chip piezo buzzer. In this paper, we report that frequency tuning can also be used to control the direction (forward or backward) of the rectified DC flow in a single device. Initially, we observed that certain devices provided DC flow in the "forward" direction expected from previous work with a similar valve geometry, and the maximum DC flow occurred at the same frequency as a prominent peak in the AC flow magnitude, as expected. However, devices of a slightly different geometry provided the DC flow in the opposite direction and at a frequency well below the peak AC flow. Using an equivalent electrical circuit model, we found that the "forward" DC flow occurred at the series resonance frequency (with large AC flow peak), while the "backward" DC flow occurred at a less obvious parallel resonance (a valley in AC flow magnitude). We also observed that the DC flow occurred only when there was a measurable differential in the AC flow magnitude across the valve, and the DC flow direction was from the channel with large AC flow magnitude to that with small AC flow magnitude. Using these observations and the AC flow predictions from the equivalent circuit model, we designed a device with an AC flowrate frequency profile that was expected to allow the DC flow in opposite directions at two distinct frequencies. The fabricated device showed the expected flow reversal at the expected frequencies. This approach expands the flow control toolkit to include both magnitude and direction control in frequency-tuned microfluidic pumps. The work also raises interesting questions about the

  3. Estimating BrAC from transdermal alcohol concentration data using the BrAC estimator software program.

    PubMed

    Luczak, Susan E; Rosen, I Gary

    2014-08-01

    Transdermal alcohol sensor (TAS) devices have the potential to allow researchers and clinicians to unobtrusively collect naturalistic drinking data for weeks at a time, but the transdermal alcohol concentration (TAC) data these devices produce do not consistently correspond with breath alcohol concentration (BrAC) data. We present and test the BrAC Estimator software, a program designed to produce individualized estimates of BrAC from TAC data by fitting mathematical models to a specific person wearing a specific TAS device. Two TAS devices were worn simultaneously by 1 participant for 18 days. The trial began with a laboratory alcohol session to calibrate the model and was followed by a field trial with 10 drinking episodes. Model parameter estimates and fit indices were compared across drinking episodes to examine the calibration phase of the software. Software-generated estimates of peak BrAC, time of peak BrAC, and area under the BrAC curve were compared with breath analyzer data to examine the estimation phase of the software. In this single-subject design with breath analyzer peak BrAC scores ranging from 0.013 to 0.057, the software created consistent models for the 2 TAS devices, despite differences in raw TAC data, and was able to compensate for the attenuation of peak BrAC and latency of the time of peak BrAC that are typically observed in TAC data. This software program represents an important initial step for making it possible for non mathematician researchers and clinicians to obtain estimates of BrAC from TAC data in naturalistic drinking environments. Future research with more participants and greater variation in alcohol consumption levels and patterns, as well as examination of gain scheduling calibration procedures and nonlinear models of diffusion, will help to determine how precise these software models can become. Copyright © 2014 by the Research Society on Alcoholism.

  4. AC electroosmosis in microchannels packed with a porous medium

    NASA Astrophysics Data System (ADS)

    Kang, Yuejun; Yang, Chun; Huang, Xiaoyang

    2004-08-01

    This paper presents a theoretical study on ac-driven electroosmotic flow in both open-end and closed-end microchannels packed with uniform charged spherical microparticles. The time-periodic oscillating electroosmotic flow in an open-end capillary in response to the application of an alternating (ac) electric field is obtained using the Green function approach. The analysis is based on the Carman-Kozeny theory. The backpressure associated with the counter-flow in a closed-end capillary is obtained by analytically solving the modified Brinkman momentum equation. It is demonstrated that in a microchannel with its two ends connected to reservoirs and subject to ambient pressure, the oscillating Darcy velocity profile depends on both the pore size and the excitation frequency; such effects are coupled through an important aspect ratio of the tubule radius to the Stokes penetration depth. For a fixed pore size, the magnitude of the ac electroosmotic flow decreases with increasing frequency. With increasing pore size, however, the magnitude of the maximum velocity shows two different trends with respect to the excitation frequency: it gets higher in the low frequency domain, and gets lower in the high frequency domain. In a microchannel with closed ends, for a fixed excitation frequency, use of smaller packing particles can generate higher backpressure. For a fixed pore size, the backpressure magnitude shows two different trends changing with the excitation frequency. When the excitation frequency is lower than the system characteristic frequency, the backpressure decreases with increasing excitation frequency. When the excitation frequency is higher than the system characteristic frequency, the backpressure increases with increasing excitation frequency.

  5. AC-electric field dependent electroformation of giant lipid vesicles.

    PubMed

    Politano, Timothy J; Froude, Victoria E; Jing, Benxin; Zhu, Yingxi

    2010-08-01

    Giant vesicles of larger than 5 microm, which have been of intense interest for their potential as drug delivery vehicles and as a model system for cell membranes, can be rapidly formed from a spin-coated lipid thin film under an electric field. In this work, we explore the AC-field dependent electroformation of giant lipid vesicles in aqueous media over a wide range of AC-frequency from 1 Hz to 1 MHz and peak-to-peak field strength from 0.212 V/mm to 40 V/mm between two parallel conducting electrode surfaces. By using fluorescence microscopy, we perform in-situ microscopic observations of the structural evolution of giant vesicles formed from spin-coated lipid films under varied uniform AC-electric fields. The real-time observation of bilayer bulging from the lipid film, vesicle growth and fusing further examine the critical role of AC-induced electroosmotic flow of surrounding fluids for giant vesicle formation. A rich AC-frequency and field strength phase diagram is obtained experimentally to predict the AC-electroformation of giant unilamellar vesicles (GUVs) of l-alpha-phosphatidylcholine, where a weak dependence of vesicle size on AC-frequency is observed at low AC-field voltages, showing decreased vesicle size with a narrowed size distribution with increased AC-frequency. Formation of vesicles was shown to be constrained by an upper field strength of 10 V/mm and an upper AC-frequency of 10 kHz. Within these parameters, giant lipid vesicles were formed predominantly unilamellar and prevalent across the entire electrode surfaces. Copyright 2010 Elsevier B.V. All rights reserved.

  6. Study on AC loss measurements of HTS power cable for standardizing

    NASA Astrophysics Data System (ADS)

    Mukoyama, Shinichi; Amemiya, Naoyuki; Watanabe, Kazuo; Iijima, Yasuhiro; Mido, Nobuhiro; Masuda, Takao; Morimura, Toshiya; Oya, Masayoshi; Nakano, Tetsutaro; Yamamoto, Kiyoshi

    2017-09-01

    High-temperature superconducting power cables (HTS cables) have been developed for more than 20 years. In addition of the cable developments, the test methods of the HTS cables have been discussed and proposed in many laboratories and companies. Recently the test methods of the HTS cables is required to standardize and to common in the world. CIGRE made the working group (B1-31) for the discussion of the test methods of the HTS cables as a power cable, and published the recommendation of the test method. Additionally, IEC TC20 submitted the New Work Item Proposal (NP) based on the recommendation of CIGRE this year, IEC TC20 and IEC TC90 started the standardization work on Testing of HTS AC cables. However, the individual test method that used to measure a performance of HTS cables hasn’t been established as world’s common methods. The AC loss is one of the most important properties to disseminate low loss and economical efficient HTS cables in the world. We regard to establish the method of the AC loss measurements in rational and in high accuracy. Japan is at a leading position in the AC loss study, because Japanese researchers have studied on the AC loss technically and scientifically, and also developed the effective technologies for the AC loss reduction. The JP domestic commission of TC90 made a working team to discussion the methods of the AC loss measurements for aiming an international standard finally. This paper reports about the AC loss measurement of two type of the HTS conductors, such as a HTS conductor without a HTS shield and a HTS conductor with a HTS shield. The AC loss measurement method is suggested by the electrical method..

  7. Fractional flow in fractured chalk; a flow and tracer test revisited.

    PubMed

    Odling, N E; West, L J; Hartmann, S; Kilpatrick, A

    2013-04-01

    A multi-borehole pumping and tracer test in fractured chalk is revisited and reinterpreted in the light of fractional flow. Pumping test data analyzed using a fractional flow model gives sub-spherical flow dimensions of 2.2-2.4 which are interpreted as due to the partially penetrating nature of the pumped borehole. The fractional flow model offers greater versatility than classical methods for interpreting pumping tests in fractured aquifers but its use has been hampered because the hydraulic parameters derived are hard to interpret. A method is developed to convert apparent transmissivity and storativity (L(4-n)/T and S(2-n)) to conventional transmissivity and storativity (L2/T and dimensionless) for the case where flow dimension, 2flow model. In the case illustrated, improved fits to drawdown data are obtained and the resultant transmissivities and storativities are found to be lower by 30% and an order of magnitude respectively, than estimates from classical methods. The revised hydraulic parameters are used in a reinterpretation of a tracer test using an analytical dual porosity model of solute transport incorporating matrix diffusion and modified for fractional flow. Model results show smaller fracture apertures, spacings and dispersivities than those when 2D flow is assumed. The pumping and tracer test results and modeling presented illustrate the importance of recognizing the potential fractional nature of flow generated by partially penetrating boreholes in fractured aquifers in estimating aquifer properties and interpreting tracer breakthrough curves. Copyright © 2013 Elsevier B.V. All rights reserved.

  8. Optical Air Flow Measurements for Flight Tests and Flight Testing Optical Air Flow Meters

    NASA Technical Reports Server (NTRS)

    Jentink, Henk W.; Bogue, Rodney K.

    2005-01-01

    Optical air flow measurements can support the testing of aircraft and can be instrumental to in-flight investigations of the atmosphere or atmospheric phenomena. Furthermore, optical air flow meters potentially contribute as avionics systems to flight safety and as air data systems. The qualification of these instruments for the flight environment is where we encounter the systems in flight testing. An overview is presented of different optical air flow measurement techniques applied in flight and what can be achieved with the techniques for flight test purposes is reviewed. All in-flight optical airflow velocity measurements use light scattering. Light is scattered on both air molecules and aerosols entrained in the air. Basic principles of making optical measurements in flight, some basic optical concepts, electronic concepts, optoelectronic interfaces, and some atmospheric processes associated with natural aerosols are reviewed. Safety aspects in applying the technique are shortly addressed. The different applications of the technique are listed and some typical examples are presented. Recently NASA acquired new data on mountain rotors, mountain induced turbulence, with the ACLAIM system. Rotor position was identified using the lidar system and the potentially hazardous air flow profile was monitored by the ACLAIM system.

  9. Impact of a Geometric Correction for Proximal Flow Constraint on the Assessment of Mitral Regurgitation Severity Using the Proximal Flow Convergence Method.

    PubMed

    Jang, Jeong Yoon; Kang, Joon-Won; Yang, Dong Hyun; Lee, Sahmin; Sun, Byung Joo; Kim, Dae-Hee; Song, Jong-Min; Kang, Duk-Hyun; Song, Jae-Kwan

    2018-03-01

    Overestimation of the severity of mitral regurgitation (MR) by the proximal isovelocity surface area (PISA) method has been reported. We sought to test whether angle correction (AC) of the constrained flow field is helpful to eliminate overestimation in patients with eccentric MR. In a total of 33 patients with MR due to prolapse or flail mitral valve, both echocardiography and cardiac magnetic resonance image (CMR) were performed to calculate regurgitant volume (RV). In addition to RV by conventional PISA (RV PISA ), convergence angle (α) was measured from 2-dimensional Doppler color flow maps and RV was corrected by multiplying by α/180 (RV AC ). RV measured by CMR (RV CMR ) was used as a gold standard, which was calculated by the difference between total stroke volume measured by planimetry of the short axis slices and aortic stroke volume by phase-contrast image. The correlation between RV CMR and RV by echocardiography was modest [RV CMR vs. RV PISA (r = 0.712, p < 0.001) and RV CMR vs. RV AC (r = 0.766, p < 0.001)]. However, RV PISA showed significant overestimation (RV PISA - RV CMR = 50.6 ± 40.6 mL vs. RV AC - RV CMR = 7.7 ± 23.4 mL, p < 0.001). The overall accuracy of RV PISA for diagnosis of severe MR, defined as RV ≥ 60 mL, was 57.6% (19/33), whereas it increased to 84.8% (28/33) by using RV AC ( p = 0.028). Conventional PISA method tends to provide falsely large RV in patients with eccentric MR and a simple geometric AC of the proximal constraint flow largely eliminates overestimation.

  10. AC Initiation System.

    DTIC Science & Technology

    An ac initiation system is described which uses three ac transmission signals interlocked for safety by frequency, phase, and power discrimination...The ac initiation system is pre-armed by the application of two ac signals have the proper phases, and activates a load when an ac power signal of the proper frequency and power level is applied. (Author)

  11. Enhanced cell trapping throughput using DC-biased AC electric field in a dielectrophoresis-based fluidic device with densely packed silica beads.

    PubMed

    Lewpiriyawong, Nuttawut; Xu, Guolin; Yang, Chun

    2018-03-01

    This paper presents the use of DC-biased AC electric field for enhancing cell trapping throughput in an insulator-based dielectrophoretic (iDEP) fluidic device with densely packed silica beads. Cell suspension is carried through the iDEP device by a pressure-driven flow. Under an applied DC-biased AC electric field, DEP trapping force is produced as a result of non-uniform electric field induced by the gap of electrically insulating silica beads packed between two mesh electrodes that allow both fluid and cells to pass through. While the AC component is mainly to control the magnitude of DEP trapping force, the DC component generates local electroosmotic (EO) flow in the cavity between the beads and the EO flow can be set to move along or against the main pressure-driven flow. Our experimental and simulation results show that desirable trapping is achieved when the EO flow direction is along (not against) the main flow direction. Using our proposed DC-biased AC field, the device can enhance the trapping throughput (in terms of the flowrate of cell suspension) up to five times while yielding almost the same cell capture rates as compared to the pure AC field case. Additionally, the device was demonstrated to selectively trap dead yeast cells from a mixture of flowing live and dead yeast cells. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  12. AC propulsion system for an electric vehicle, phase 2

    NASA Astrophysics Data System (ADS)

    Slicker, J. M.

    1983-06-01

    A second-generation prototype ac propulsion system for a passenger electric vehicle was designed, fabricated, tested, installed in a modified Mercury Lynx vehicle and track tested at the Contractor's site. The system consisted of a Phase 2, 18.7 kw rated ac induction traction motor, a 192-volt, battery powered, pulse-width-modulated, transistorized inverter packaged for under rear seat installation, a 2-axis, 2-speed, automatically-shifted mechanical transaxle and a microprocessor-based powertrain/vehicle controller. A diagnostics computer to assist tuning and fault finding was fabricated. Dc-to-mechanical-system efficiency varied from 78% to 82% as axle speed/torque ranged from 159 rpm/788 nm to 65 rpm/328 nm. Track test efficiency results suggest that the ac system will be equal or superior to dc systems when driving urban cycles. Additional short-term work is being performed under a third contract phase (AC-3) to raise transaxle efficiency to predicted levels, and to improve starting and shifting characteristics. However, the long-term challenge to the system's viability remains inverter cost. A final report on the Phase 2 system, describing Phase 3 modifications, will be issued at the conclusion of AC-3.

  13. AC propulsion system for an electric vehicle, phase 2

    NASA Technical Reports Server (NTRS)

    Slicker, J. M.

    1983-01-01

    A second-generation prototype ac propulsion system for a passenger electric vehicle was designed, fabricated, tested, installed in a modified Mercury Lynx vehicle and track tested at the Contractor's site. The system consisted of a Phase 2, 18.7 kw rated ac induction traction motor, a 192-volt, battery powered, pulse-width-modulated, transistorized inverter packaged for under rear seat installation, a 2-axis, 2-speed, automatically-shifted mechanical transaxle and a microprocessor-based powertrain/vehicle controller. A diagnostics computer to assist tuning and fault finding was fabricated. Dc-to-mechanical-system efficiency varied from 78% to 82% as axle speed/torque ranged from 159 rpm/788 nm to 65 rpm/328 nm. Track test efficiency results suggest that the ac system will be equal or superior to dc systems when driving urban cycles. Additional short-term work is being performed under a third contract phase (AC-3) to raise transaxle efficiency to predicted levels, and to improve starting and shifting characteristics. However, the long-term challenge to the system's viability remains inverter cost. A final report on the Phase 2 system, describing Phase 3 modifications, will be issued at the conclusion of AC-3.

  14. An electrode polarization impedance based flow sensor for low water flow measurement

    NASA Astrophysics Data System (ADS)

    Yan, Tinghu; Sabic, Darko

    2013-06-01

    This note describes an electrode polarization impedance based flow sensor for low water flow measurement. It consists of two pairs of stainless steel electrodes set apart and inserted into a non-conductive flow tube with each pair of electrodes placed diametrically at the opposite sides. The flow sensor is modeled as a typical four-electrode system of which two electrodes are current-carrying and the other two serve as output pick ups. The polarization impedances of the two current carrying electrodes are affected by water flows resulting in changes of differential potential between the two pick-up electrodes which are separated by the same fluid. The interrogation of the two excitation electrodes with dc biased ac signals offers significantly higher sensor sensitivities to flow. The prototype flow sensor constructed for a 20 mm diameter pipeline was able to measure water flow rate as low as tested at 1.06 l h-1 and remained sensitive at a flow rate of 25.18 l h-1 when it was driven with a sinusoidal voltage at 1000 Hz with a peak ac amplitude of 2 V and a dc offset of +8 V. The nonlinear characteristics of the sensor response indicate that the sensor is more sensitive at low flows and will not be able to measure at very high flows. Additional experiments are needed to evaluate the influences of impurities, chemical species, ions constituents, conductivity and temperature over a practical range of residential water conditions, the effects of fluctuating ground signals, measurement uncertainty, power consumption, compensation of effects and practical operations. The flow sensor (principle) presented may be used as (in) a secondary sensor in combination with an existing electronic water meter to extend the low end of measurement range in residential water metering.

  15. Transverse ac-driven and geometric ratchet effects for vortices in conformal crystal pinning arrays

    DOE PAGES

    Reichhardt, Charles; Reichhardt, Cynthia Jane Olsen

    2016-02-11

    A conformal pinning array is created by taking a conformal transformation of a uniform hexagonal lattice to create a structure in which the sixfold ordering of the original lattice is preserved but which has a spatial gradient in the pinning site density. With a series of conformal arrays it is possible to create asymmetric substrates, and it was previously shown that when an ac drive is applied parallel to the asymmetry direction, a pronounced ratchet effect occurs with a net dc flow of vortices in the same direction as the ac drive. Here, in this article, we show that whenmore » the ac drive is applied perpendicular to the substrate asymmetry direction, it is possible to realize a transverse ratchet effect where a net dc flow of vortices is generated perpendicular to the ac drive. The conformal transverse ratchet effect is distinct from previous versions of transverse ratchets in that it occurs due to the generation of non-Gaussian transverse vortex velocity fluctuations by the plastic motion of vortices, so that the system behaves as a noise correlation ratchet. The transverse ratchet effect is much more pronounced in the conformal arrays than in random gradient arrays and is absent in square gradient arrays due the different nature of the vortex flow in each geometry. We show that a series of reversals can occur in the transverse ratchet effect due to changes in the vortex flow across the pinning gradient as a function of vortex filling, pinning strength, and ac amplitude. We also consider the case where a dc drive applied perpendicular to the substrate asymmetry direction generates a net flow of vortices perpendicular to the dc drive, producing what is known as a geometric or drift ratchet that again arises due to non-Gaussian dynamically generated fluctuations. The drift ratchet is more efficient than the ac driven ratchet and also exhibits a series of reversals for varied parameters. Lastly, our results should be general to a wide class of systems

  16. Large amplitude Fourier transformed ac voltammetry at a rotating disc electrode: a versatile technique for covering Levich and flow rate insensitive regimes in a single experiment.

    PubMed

    Bano, Kiran; Kennedy, Gareth F; Zhang, Jie; Bond, Alan M

    2012-04-14

    The theory for large amplitude Fourier transformed ac voltammetry at a rotating disc electrode is described. Resolution of time domain data into dc and ac harmonic components reveals that the mass transport for the dc component is controlled by convective-diffusion, while the background free higher order harmonic components are flow rate insensitive and mainly governed by linear diffusion. Thus, remarkable versatility is available; Levich behaviour of the dc component limiting current provides diffusion coefficient values and access to higher harmonics allows fast electrode kinetics to be probed. Two series of experiments (dc and ac voltammetry) have been required to extract these parameters; here large amplitude ac voltammetry with RDE methodology is used to demonstrate that kinetics and diffusion coefficient information can be extracted from a single experiment. To demonstrate the power of this approach, theoretical and experimental comparisons of data obtained for the reversible [Ru(NH(3))(6)](3+/2+) and quasi-reversible [Fe(CN)(6)](3-/4-) electron transfer processes are presented over a wide range of electrode rotation rates and with different concentrations and electrode materials. Excellent agreement of experimental and simulated data is achieved, which allows parameters such as electron transfer rate, diffusion coefficient, uncompensated resistance and others to be determined using a strategically applied approach that takes into account the different levels of sensitivity of each parameter to the dc or the ac harmonic.

  17. First AC loss test and analysis of a Bi2212 cable-in-conduit conductor for fusion application

    NASA Astrophysics Data System (ADS)

    Qin, Jinggang; Shi, Yi; Wu, Yu; Li, Jiangang; Wang, Qiuliang; He, Yuxiang; Dai, Chao; Liu, Fang; Liu, Huajun; Mao, Zhehua; Nijhuis, Arend; Zhou, Chao; Devred, Arnaud

    2018-01-01

    The main goal of the Chinese fusion engineering test reactor (CFETR) is to build a fusion engineering tokamak reactor with a fusion power of 50-200 MW, and plan to test the breeding tritium during the fusion reaction. This may require a maximum magnetic field of the central solenoid and toroidal field coils up to 15 T. New magnet technologies should be developed for the next generation of fusion reactors with higher requirements. Bi2Sr2CaCu2Ox (Bi2212) is considered as a potential and promising superconductor for the magnets in the CFETR. R&D activities are ongoing at the Institute of Plasma Physics, Chinese Academy of Sciences for demonstration of the feasibility of a CICC based on Bi2212 round wire. One sub-size conductor cabled with 42 wires was designed, manufactured and tested with limited strand indentation during cabling and good transport performance. In this paper, the first test results and analysis on the AC loss of Bi2212 round wires and cabled conductor samples are presented. Furthermore, the impact of mechanical load on the AC loss of the sub-size conductor is investigated to represent the operation conditions with electromagnetic loads. The first tests provide an essential basis for the validation of Bi2212 CICC and its application in fusion magnets.

  18. Analysis of flow reversal test

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

    Cheng, L.Y.; Tichler, P.R.

    A series of tests has been conducted to measure the dryout power associated with a flow transient whereby the coolant in a heated channel undergoes a change in flow direction. An analysis of the test was made with the aid of a system code, RELAP5. A dryout criterion was developed in terms of a time-averaged void fraction calculated by RELAP5 for the heated channel. The dryout criterion was also compared with several CHF correlations developed for the channel geometry.

  19. Cold Flow Propulsion Test Complex Pulse Testing

    NASA Technical Reports Server (NTRS)

    McDougal, Kris

    2016-01-01

    When the propellants in a liquid rocket engine burn, the rocket not only launches and moves in space, it causes forces that interact with the vehicle itself. When these interactions occur under specific conditions, the vehicle's structures and components can become unstable. One instability of primary concern is termed pogo (named after the movement of a pogo stick), in which the oscillations (cycling movements) cause large loads, or pressure, against the vehicle, tanks, feedlines, and engine. Marshall Space Flight Center (MSFC) has developed a unique test technology to understand and quantify the complex fluid movements and forces in a liquid rocket engine that contribute strongly to both engine and integrated vehicle performance and stability. This new test technology was established in the MSFC Cold Flow Propulsion Test Complex to allow injection and measurement of scaled propellant flows and measurement of the resulting forces at multiple locations throughout the engine.

  20. System and method for determining stator winding resistance in an AC motor using motor drives

    DOEpatents

    Lu, Bin; Habetler, Thomas G; Zhang, Pinjia

    2013-02-26

    A system and method for determining the stator winding resistance of AC motors is provided. The system includes an AC motor drive having an input connectable to an AC source and an output connectable to an input terminal of an AC motor, a pulse width modulation (PWM) converter having switches therein to control current flow and terminal voltages in the AC motor, and a control system connected to the PWM converter. The control system generates a command signal to cause the PWM converter to control an output of the AC motor drive corresponding to an input to the AC motor, selectively generates a modified command signal to cause the PWM converter to inject a DC signal into the output of the AC motor drive, and determines a stator winding resistance of the AC motor based on the DC signal of at least one of the voltage and current.

  1. Design and implementation of co-operative control strategy for hybrid AC/DC microgrids

    NASA Astrophysics Data System (ADS)

    Mahmud, Rasel

    This thesis is mainly divided in two major sections: 1) Modeling and control of AC microgrid, DC microgrid, Hybrid AC/DC microgrid using distributed co-operative control, and 2) Development of a four bus laboratory prototype of an AC microgrid system. At first, a distributed cooperative control (DCC) for a DC microgrid considering the state-of-charge (SoC) of the batteries in a typical plug-in-electric-vehicle (PEV) is developed. In DC microgrids, this methodology is developed to assist the load sharing amongst the distributed generation units (DGs), according to their ratings with improved voltage regulation. Subsequently, a DCC based control algorithm for AC microgrid is also investigated to improve the performance of AC microgrid in terms of power sharing among the DGs, voltage regulation and frequency deviation. The results validate the advantages of the proposed methodology as compared to traditional droop control of AC microgrid. The DCC-based control methodology for AC microgrid and DC microgrid are further expanded to develop a DCC-based power management algorithm for hybrid AC/DC microgrid. The developed algorithm for hybrid microgrid controls the power flow through the interfacing converter (IC) between the AC and DC microgrids. This will facilitate the power sharing between the DGs according to their power ratings. Moreover, it enables the fixed scheduled power delivery at different operating conditions, while maintaining good voltage regulation and improved frequency profile. The second section provides a detailed explanation and step-by-step design and development of an AC/DC microgrid testbed. Controllers for the three-phase inverters are designed and tested on different generation units along with their corresponding inductor-capacitor-inductor (LCL) filters to eliminate the switching frequency harmonics. Electric power distribution line models are developed to form the microgrid network topology. Voltage and current sensors are placed in the proper

  2. Demonstration of AC and DC charge control for the LISA test masses

    NASA Astrophysics Data System (ADS)

    Olatunde, Taiwo Janet

    2018-01-01

    Taiwo Olatunde, Stephen Apple, Andrew Chilton, Samantha Parry, Peter Wass, Guido Mueller, John W. Conklin The residual test mass acceleration in LISA must be below 3 fm/s2/√Hz at all frequencies between 0.1 and 3 mHz. Test mass charge coupled with stray electrical potentials and external electromagnetic fields is a well-known source of acceleration noise. LISA Pathfinder uses Hg lamps emitting mostly around 254 nm to discharge the test masses via photoemission, but a future LISA mission launched around 2030 will likely replace the lamps with newer UV LEDs with lower mass, better power efficiency, smaller size and higher bandwidth. This presentation will discuss charge control demonstrated on the torsion pendulum in AC and DC modes at the University of Florida using latest generation UV LEDs producing light at 240 nm with energy above the work function of pure Au. Initial results of Au quantum efficiency measurements (number of emitted electrons per incident photons) which is critical for bi-polar charge control will also be presented.

  3. The AcCell series 2000 as a support system for training and evaluation in educational and clinical settings.

    PubMed

    Greening, S E; Grohs, D H; Guidos, B J

    1997-01-01

    Providing effective training, retraining and evaluation programs, including proficiency testing programs, for cytoprofessionals is a challenge shared by many academic and clinical educators internationally. In cytopathology the quality of training has immediately transferable and critically important impacts on satisfactory performance in the clinical setting. Well-designed interactive computer-assisted instruction and testing programs have been shown to enhance initial learning and to reinforce factual and conceptual knowledge. Computer systems designed not only to promote diagnostic accuracy but to integrate and streamline work flow in clinical service settings are candidates for educational adaptation. The AcCell 2000 system, designed as a diagnostic screening support system, offers technology that is adaptable to educational needs during basic and in-service training as well as testing of screening proficiency in both locator and identification skills. We describe the considerations, approaches and applications of the AcCell 2000 system in education programs for both training and evaluation of gynecologic diagnostic screening proficiency.

  4. AC electroosmotic pump with bubble-free palladium electrodes and rectifying polymer membrane valves.

    PubMed

    Brask, Anders; Snakenborg, Detlef; Kutter, Jörg P; Bruus, Henrik

    2006-02-01

    We present the design, test and theoretical analysis of a novel micropump. The purpose is to make a pump with large flow rate (approximately 10 microL min-1) and high pressure capacity (approximately 1 bar) powered by a low voltage DeltaV<30 V. The pump is operated in AC mode with an electroosmotic actuator in connection with a full wave rectifying valve system. Individual valves are based on a flexible membrane with a slit. Bubble-free palladium electrodes are implemented in order to increase the range of applications and reduce maintenance.

  5. The effect of heat treatment and test parameters on the aqueous stress corrosion cracking of D6AC steel

    NASA Technical Reports Server (NTRS)

    Gilbreath, W. P.; Adamson, M. J.

    1974-01-01

    The crack growth behavior of D6AC steel as a function of stress intensity, stress and corrosion history and test technique, under sustained load in natural seawater, 3.3 percent NaCl solution, distilled water, and high humidity air was investigated. Reported investigations of D6AC were considered with emphasis on thermal treatment, specimen configuration, fracture toughness, crack-growth rates, initiation period, threshold, and the extension of corrosion fatigue data to sustained load conditions. Stress history effects were found to be most important in that they controlled incubation period, initial crack growth rates, and apparent threshold.

  6. ac electroosmotic pumping induced by noncontact external electrodes

    PubMed Central

    Wang, Shau-Chun; Chen, Hsiao-Ping; Chang, Hsueh-Chia

    2007-01-01

    Electroosmotic (EO) pumps based on dc electroosmosis is plagued by bubble generation and other electrochemical reactions at the electrodes at voltages beyond 1 V for electrolytes. These disadvantages limit their throughput and offset their portability advantage over mechanical syringe or pneumatic pumps. ac electroosmotic pumps at high frequency (>100 kHz) circumvent the bubble problem by inducing polarization and slip velocity on embedded electrodes,1 but they require complex electrode designs to produce a net flow. We report a new high-throughput ac EO pump design based on induced-polarization on the entire channel surface instead of just on the electrodes. Like dc EO pumps, our pump electrodes are outside of the load section and form a cm-long pump unit consisting of three circular reservoirs (3 mm in diameter) connected by a 1×1 mm channel. The field-induced polarization can produce an effective Zeta potential exceeding 1 V and an ac slip velocity estimated as 1 mm∕sec or higher, both one order of magnitude higher than earlier dc and ac pumps, giving rise to a maximum throughput of 1 μl∕sec. Polarization over the entire channel surface, quadratic scaling with respect to the field and high voltage at high frequency without electrode bubble generation are the reasons why the current pump is superior to earlier dc and ac EO pumps. PMID:19693362

  7. ac electroosmotic pumping induced by noncontact external electrodes.

    PubMed

    Wang, Shau-Chun; Chen, Hsiao-Ping; Chang, Hsueh-Chia

    2007-09-21

    Electroosmotic (EO) pumps based on dc electroosmosis is plagued by bubble generation and other electrochemical reactions at the electrodes at voltages beyond 1 V for electrolytes. These disadvantages limit their throughput and offset their portability advantage over mechanical syringe or pneumatic pumps. ac electroosmotic pumps at high frequency (>100 kHz) circumvent the bubble problem by inducing polarization and slip velocity on embedded electrodes,1 but they require complex electrode designs to produce a net flow. We report a new high-throughput ac EO pump design based on induced-polarization on the entire channel surface instead of just on the electrodes. Like dc EO pumps, our pump electrodes are outside of the load section and form a cm-long pump unit consisting of three circular reservoirs (3 mm in diameter) connected by a 1x1 mm channel. The field-induced polarization can produce an effective Zeta potential exceeding 1 V and an ac slip velocity estimated as 1 mmsec or higher, both one order of magnitude higher than earlier dc and ac pumps, giving rise to a maximum throughput of 1 mulsec. Polarization over the entire channel surface, quadratic scaling with respect to the field and high voltage at high frequency without electrode bubble generation are the reasons why the current pump is superior to earlier dc and ac EO pumps.

  8. Electrokinetically driven microfluidic mixing with patchwise surface heterogeneity and AC applied electric field

    NASA Astrophysics Data System (ADS)

    Luo, Win-Jet; Yue, Cheng-Feng

    2004-12-01

    This paper investigates two-dimensional, time-dependent electroosmotic flows driven by an AC electric field via patchwise surface heterogeneities distributed along the microchannel walls. The time-dependent flow fields through the microchannel are simulated for various patchwise heterogeneous surface patterns using the backwards-Euler time stepping numerical method. Different heterogeneous surface patterns are found to create significantly different electrokinetic transport phenomena. It is shown that the presence of oppositely charged surface heterogeneities on the microchannel walls results in the formation of localized flow circulations within the bulk flow. These circulation regions grow and decay periodically in accordance with the applied periodic AC electric field intensity. The circulations provide an effective means of enhancing species mixing in the microchannel. A suitable design of the patchwise heterogeneous surface pattern permits the mixing channel length and the retention time required to attain a homogeneous solution to be reduced significantly.

  9. Cold Flow Plume Entrainment Test Final Report NTF Test Number 2456

    NASA Technical Reports Server (NTRS)

    Ruf, Joseph H.; McDaniels, David; Mishtawy, Jason; Ramachandran, Narayanan; Hammad, Khaled J.

    2005-01-01

    As part of the Space Shuttle Return to Flight (RTF) program, Marshall Space Flight Center (MSFC) performed computational fluid dynamics (CFD) analysis to define the velocity flowfields around the Shuttle stack at liftoff. These CFD predicted velocity flowfields were used in debris transport analysis (DTA). High speed flows such as plumes induce or 'entrain' mass from the surrounding environment. Previous work had shown that CFD analysis over-predicts plume induced flows. Therefore, the DTA would tend to 1) predict more debris impacts, and 2) the debris velocity (and kinetic energy) of those impacts would be too high. At a November, 2004 peer-review it was recommended that the Liftoff DTA team quantify the uncertainty in the DTA caused by the CFD's over prediction of plume induced flow. To do so, the Liftoff DTA team needed benchmark quality data for plume induced flow to quantify the CFD accuracy and its effect on the DTA. MSFC's Nozzle Test Facility (NTF) conducted the "Nozzle Induced Flows test, P#2456" to obtain experimental data for plume induced flows for nozzle flow exhausting into q quiescent freestream. Planning for the test began in December, 2004 and the experimental data was obtained in February and March of 2005. The funding for this test was provided by MSFC's Space Shuttle Propulsion Systems Integration and Engineering office.

  10. Test Methodologies for Hydrogen Sensor Performance Assessment: Chamber vs. Flow Through Test Apparatus: Preprint

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

    Buttner, William J; Hartmann, Kevin S; Schmidt, Kara

    Certification of hydrogen sensors to standards often prescribes using large-volume test chambers [1, 2]. However, feedback from stakeholders such as sensor manufacturers and end-users indicate that chamber test methods are often viewed as too slow and expensive for routine assessment. Flow through test methods potentially are an efficient, cost-effective alternative for sensor performance assessment. A large number of sensors can be simultaneously tested, in series or in parallel, with an appropriate flow through test fixture. The recent development of sensors with response times of less than 1s mandates improvements in equipment and methodology to properly capture the performance of thismore » new generation of fast sensors; flow methods are a viable approach for accurate response and recovery time determinations, but there are potential drawbacks. According to ISO 26142 [1], flow through test methods may not properly simulate ambient applications. In chamber test methods, gas transport to the sensor can be dominated by diffusion which is viewed by some users as mimicking deployment in rooms and other confined spaces. Alternatively, in flow through methods, forced flow transports the gas to the sensing element. The advective flow dynamics may induce changes in the sensor behaviour relative to the quasi-quiescent condition that may prevail in chamber test methods. One goal of the current activity in the JRC and NREL sensor laboratories [3, 4] is to develop a validated flow through apparatus and methods for hydrogen sensor performance testing. In addition to minimizing the impact on sensor behaviour induced by differences in flow dynamics, challenges associated with flow through methods include the ability to control environmental parameters (humidity, pressure and temperature) during the test and changes in the test gas composition induced by chemical reactions with upstream sensors. Guidelines on flow through test apparatus design and protocols for the

  11. The Feasibility of Applying AC Driven Low-Temperature Plasma for Multi-Cycle Detonation Initiation

    NASA Astrophysics Data System (ADS)

    Zheng, Dianfeng

    2016-11-01

    Ignition is a key system in pulse detonation engines (PDE). As advanced ignition methods, nanosecond pulse discharge low-temperature plasma ignition is used in some combustion systems, and continuous alternating current (AC) driven low-temperature plasma using dielectric barrier discharge (DBD) is used for the combustion assistant. However, continuous AC driven plasmas cannot be used for ignition in pulse detonation engines. In this paper, experimental and numerical studies of pneumatic valve PDE using an AC driven low-temperature plasma igniter were described. The pneumatic valve was jointly designed with the low-temperature plasma igniter, and the numerical simulation of the cold-state flow field in the pneumatic valve showed that a complex flow in the discharge area, along with low speed, was beneficial for successful ignition. In the experiments ethylene was used as the fuel and air as oxidizing agent, ignition by an AC driven low-temperature plasma achieved multi-cycle intermittent detonation combustion on a PDE, the working frequency of the PDE reached 15 Hz and the peak pressure of the detonation wave was approximately 2.0 MPa. The experimental verifications of the feasibility in PDE ignition expanded the application field of AC driven low-temperature plasma. supported by National Natural Science Foundation of China (No. 51176001)

  12. Aligned Immobilization of Proteins Using AC Electric Fields.

    PubMed

    Laux, Eva-Maria; Knigge, Xenia; Bier, Frank F; Wenger, Christian; Hölzel, Ralph

    2016-03-01

    Protein molecules are aligned and immobilized from solution by AC electric fields. In a single-step experiment, the enhanced green fluorescent proteins are immobilized on the surface as well as at the edges of planar nanoelectrodes. Alignment is found to follow the molecules' geometrical shape with their longitudinal axes parallel to the electric field. Simultaneous dielectrophoretic attraction and AC electroosmotic flow are identified as the dominant forces causing protein movement and alignment. Molecular orientation is determined by fluorescence microscopy based on polarized excitation of the proteins' chromophores. The chromophores' orientation with respect to the whole molecule supports X-ray crystal data. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  13. FLOW TESTING AND ANALYSIS OF THE FSP-1 EXPERIMENT

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

    Hawkes, Grant L.; Jones, Warren F.; Marcum, Wade

    The U.S. High Performance Research Reactor Conversions fuel development team is focused on developing and qualifying the uranium-molybdenum (U-Mo) alloy monolithic fuel to support conversion of domestic research reactors to low enriched uranium. Several previous irradiations have demonstrated the favorable behavior of the monolithic fuel. The Full Scale Plate 1 (FSP-1) fuel plate experiment will be irradiated in the northeast (NE) flux trap of the Advanced Test Reactor (ATR). This fueled experiment contains six aluminum-clad fuel plates consisting of monolithic U-Mo fuel meat. Flow testing experimentation and hydraulic analysis have been performed on the FSP-1 experiment to be irradiated inmore » the ATR at the Idaho National Laboratory (INL). A flow test experiment mockup of the FSP-1 experiment was completed at Oregon State University. Results of several flow test experiments are compared with analyses. This paper reports and shows hydraulic analyses are nearly identical to the flow test results. A water velocity of 14.0 meters per second is targeted between the fuel plates. Comparisons between FSP-1 measurements and this target will be discussed. This flow rate dominates the flow characteristics of the experiment and model. Separate branch flows have minimal effect on the overall experiment. A square flow orifice was placed to control the flowrate through the experiment. Four different orifices were tested. A flow versus delta P curve for each orifice is reported herein. Fuel plates with depleted uranium in the fuel meat zone were used in one of the flow tests. This test was performed to evaluate flow test vibration with actual fuel meat densities and reported herein. Fuel plate deformation tests were also performed and reported.« less

  14. National Fuel Cell Bus Program : Accelerated Testing Report, AC Transit

    DOT National Transportation Integrated Search

    2009-01-01

    This is an evaluation of hydrogen fuel cell transit buses operating at AC Transit in revenue service since March 20, 2006 compared to similar diesel buses operating from the same depot. This evaluation report includes results from November 2007 throu...

  15. Effect of an ac Perturbation on the Electroosmotic Behavior of a Cation-Exchange Membrane. Influence of the Cation Nature.

    PubMed

    Barragán, V. M.; Bauzá, C. Ruíz

    2001-08-01

    The effect of an ac sinusoidal perturbation of known amplitude and frequency superimposed on the usual dc applied electric voltage difference on the electroosmotic flow through a typical cation-exchange membrane has been studied using different monovalent electrolytes. As a general trend, the presence of the ac perturbation increases the value of the electroosmotic flow with respect to the value in the absence of ac perturbation. A dispersion of the electroosmotic permeability on the frequency of the applied ac signal has been found for the three studied electrolytes, observing that the electroosmotic permeability reaches maximum values for some characteristic values of the frequency. This behavior may be related to the different relaxation processes in heterogeneous mediums. Copyright 2001 Academic Press.

  16. An MRI-Compatible High Frequency AC Resistive Heating System for Homeothermic Maintenance in Small Animals

    PubMed Central

    Gomes, Ana L.; Kinchesh, Paul; Kersemans, Veerle; Allen, Philip D.; Smart, Sean C.

    2016-01-01

    Purpose To develop an MRI-compatible resistive heater, using high frequency alternating current (AC), for temperature maintenance of anaesthetised animals. Materials and Methods An MRI-compatible resistive electrical heater was formed from narrow gauge wire connected to a high frequency (10–100 kHz) AC power source. Multiple gradient echo images covering a range of echo times, and pulse-acquire spectra were acquired with the wire heater powered using high frequency AC or DC power sources and without any current flowing in order to assess the sensitivity of the MRI acquisitions to the presence of current flow through the heater wire. The efficacy of temperature maintenance using the AC heater was assessed by measuring rectal temperature immediately following induction of general anaesthesia for a period of 30 minutes in three different mice. Results Images and spectra acquired in the presence and absence of 50–100 kHz AC through the wire heater were indistinguishable, whereas DC power created field shifts and lineshape distortions. Temperature lost during induction of anaesthesia was recovered within approximately 20 minutes and a stable temperature was reached as the mouse’s temperature approached the set target. Conclusion The AC-powered wire heater maintains adequate heat input to the animal to maintain body temperature, and does not compromise image quality. PMID:27806062

  17. Pixel-based CTE Correction of ACS/WFC: Modifications To The ACS Calibration Pipeline (CALACS)

    NASA Astrophysics Data System (ADS)

    Smith, Linda J.; Anderson, J.; Armstrong, A.; Avila, R.; Bedin, L.; Chiaberge, M.; Davis, M.; Ferguson, B.; Fruchter, A.; Golimowski, D.; Grogin, N.; Hack, W.; Lim, P. L.; Lucas, R.; Maybhate, A.; McMaster, M.; Ogaz, S.; Suchkov, A.; Ubeda, L.

    2012-01-01

    The Advanced Camera for Surveys (ACS) was installed on the Hubble Space Telescope (HST) nearly ten years ago. Over the last decade, continuous exposure to the harsh radiation environment has degraded the charge transfer efficiency (CTE) of the CCDs. The worsening CTE impacts the science that can be obtained by altering the photometric, astrometric and morphological characteristics of sources, particularly those farthest from the readout amplifiers. To ameliorate these effects, Anderson & Bedin (2010, PASP, 122, 1035) developed a pixel-based empirical approach to correcting ACS data by characterizing the CTE profiles of trails behind warm pixels in dark exposures. The success of this technique means that it is now possible to correct full-frame ACS/WFC images for CTE degradation in the standard data calibration and reduction pipeline CALACS. Over the past year, the ACS team at STScI has developed, refined and tested the new software. The details of this work are described in separate posters. The new code is more effective at low flux levels (< 50 electrons) than the original Anderson & Bedin code, and employs a more accurate time and temperature dependence for CTE. The new CALACS includes the automatic removal of low-level bias stripes (produced by the post-repair ACS electronics) and pixel-based CTE correction. In addition to the standard cosmic ray corrected, flat-fielded and drizzled data products (crj, flt and drz files) there are three new equivalent files (crc, flc and drc) which contain the CTE-corrected data products. The user community will be able to choose whether to use the standard or CTE-corrected products.

  18. Water Flow Test at Launch Complex 39B

    NASA Image and Video Library

    2017-12-20

    Water flowed during a test at Launch Complex 39B at NASA’s Kennedy Space Center in Florida. About 450,000 gallons of water flowed at high speed from a holding tank through new and modified piping and valves, the flame trench, flame deflector nozzles and mobile launcher interface risers during a wet flow test at Launch Complex 39B. At peak flow, the water reached about 100 feet in the air above the pad surface. The test was a milestone to confirm and baseline the performance of the Ignition Overpressure/Sound Suppression system. During launch of NASA's Space Launch System rocket and Orion spacecraft, the high-speed water flow will help protect the vehicle from the extreme acoustic and temperature environment during ignition and liftoff.

  19. AC-130 Employment

    DTIC Science & Technology

    2006-01-01

    1 AC -130 Employment Subject Area Aviation EWS 2006 Author Captain Robert Hornick, USMC Report Documentation Page Form ApprovedOMB No. 0704...00-2006 4. TITLE AND SUBTITLE AC -130 Employment 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR(S) 5d. PROJECT NUMBER... AC -130 gunship is an aircraft that can provide all of these needs. Regrettably, there are too few AC -130’s in the inventory to cover all the needs

  20. Road load simulator tests of the Gould phase 1 functional model silicon controlled rectifier ac motor controller for electric vehicles

    NASA Astrophysics Data System (ADS)

    Gourash, F.

    1984-02-01

    The test results for a functional model ac motor controller for electric vehicles and a three-phase induction motor which were dynamically tested on the Lewis Research Center road load simulator are presented. Results show that the controller has the capability to meet the SAE-J227a D cycle test schedule and to accelerate a 1576-kg (3456-lb) simulated vehicle to a cruise speed of 88.5 km/hr (55 mph). Combined motor controller efficiency is 72 percent and the power inverter efficiency alone is 89 percent for the cruise region of the D cycle. Steady state test results for motoring, regeneration, and thermal data obtained by operating the simulator as a conventional dynamometer are in agreement with the contractor's previously reported data. The regeneration test results indicate that a reduction in energy requirements for urban driving cycles is attainable with regenerative braking. Test results and data in this report serve as a data base for further development of ac motor controllers and propulsion systems for electric vehicles. The controller uses state-of-the-art silicon controlled rectifier (SCR) power semiconductors and microprocessor-based logic and control circuitry. The controller was developed by Gould Laboratories under a Lewis contract for the Department of Energy's Electric and Hybrid Vehicle program.

  1. Road load simulator tests of the Gould phase 1 functional model silicon controlled rectifier ac motor controller for electric vehicles

    NASA Technical Reports Server (NTRS)

    Gourash, F.

    1984-01-01

    The test results for a functional model ac motor controller for electric vehicles and a three-phase induction motor which were dynamically tested on the Lewis Research Center road load simulator are presented. Results show that the controller has the capability to meet the SAE-J227a D cycle test schedule and to accelerate a 1576-kg (3456-lb) simulated vehicle to a cruise speed of 88.5 km/hr (55 mph). Combined motor controller efficiency is 72 percent and the power inverter efficiency alone is 89 percent for the cruise region of the D cycle. Steady state test results for motoring, regeneration, and thermal data obtained by operating the simulator as a conventional dynamometer are in agreement with the contractor's previously reported data. The regeneration test results indicate that a reduction in energy requirements for urban driving cycles is attainable with regenerative braking. Test results and data in this report serve as a data base for further development of ac motor controllers and propulsion systems for electric vehicles. The controller uses state-of-the-art silicon controlled rectifier (SCR) power semiconductors and microprocessor-based logic and control circuitry. The controller was developed by Gould Laboratories under a Lewis contract for the Department of Energy's Electric and Hybrid Vehicle program.

  2. Superconducting ac cable

    NASA Astrophysics Data System (ADS)

    Schmidt, F.

    1980-11-01

    The components of a superconducting 110 kV ac cable for power ratings or = 2000 MVA were developed. The cable design is of the semiflexible type, with a rigid cryogenic envelope containing a flexible hollow coaxial cable core. The cable core consists of spirally wound Nb-A1 composite wires electrically insulated by high pressure polyethylene tape wrappings. A 35 m long single phase test cable with full load terminals rated at 110 kV and 10 kA was constructed and successfully tested. The results obtained prove the technical feasibility and capability of this cable design.

  3. Characterization of Flow Bench Engine Testing

    NASA Astrophysics Data System (ADS)

    Voris, Alex; Riley, Lauren; Puzinauskas, Paul

    2015-11-01

    This project was an attempt at characterizing particle image velocimetry (PIV) and swirl-meter test procedures. The flow direction and PIV seeding were evaluated for in-cylinder steady state flow of a spark ignition engine. For PIV seeding, both wet and dry options were tested. The dry particles tested were baby powder, glass particulate, and titanium dioxide. The wet particles tested were fogs created with olive oil, vegetable oil, DEHS, and silicon oil. The seeding was evaluated at 0.1 and 0.25 Lift/Diameter and at cylinder pressures of 10, 25 and 40 inches of H2O. PIV results were evaluated through visual and fluid momentum comparisons. Seeding particles were also evaluated based on particle size and cost. It was found that baby powder and glass particulate were the most effective seeding options for the current setup. The oil fogs and titanium dioxide were found to deposit very quickly on the mock cylinder and obscure the motion of the particles. Based on initial calculations and flow measurements, the flow direction should have a negligible impact on PIV and swirl-meter results. The characterizations found in this project will be used in future engine research examining the effects of intake port geometry on in-cylinder fluid motion and exhaust gas recirculation tolerances. Thanks to NSF site grant #1358991.

  4. Resource Prospector Propulsion System Cold Flow Testing

    NASA Technical Reports Server (NTRS)

    Williams, Hunter; Holt, Kim; Addona, Brad; Trinh, Huu

    2015-01-01

    Resource Prospector (RP) is a NASA mission being led by NASA Ames Research Center with current plans to deliver a scientific payload package aboard a rover to the lunar surface. As part of an early risk reduction activity, Marshall Space Flight Center (MSFC) and Johnson Space Flight Center (JSC) have jointly developed a government-version concept of a lunar lander for the mission. The spacecraft consists of two parts, the lander and the rover which carries the scientific instruments. The lander holds the rover during launch, cruise, and landing on the surface. Following terminal descent and landing the lander portion of the spacecraft become dormant after the rover embarks on the science mission. The lander will be equipped with a propulsion system for lunar descent and landing, as well as trajectory correction and attitude control maneuvers during transit to the moon. Hypergolic propellants monomethyl hydrazine and nitrogen tetroxide will be used to fuel sixteen 70-lbf descent thrusters and twelve 5-lbf attitude control thrusters. A total of four metal-diaphragm tanks, two per propellant, will be used along with a high-pressure composite-overwrapped pressure vessel for the helium pressurant gas. Many of the major propulsion system components are heritage missile hardware obtained by NASA from the Air Force. In parallel with the flight system design activities, a simulated propulsion system based on flight drawings was built for conducting a series of water flow tests to characterize the transient fluid flow of the propulsion system feed lines and to verify the critical operation modes such as system priming, waterhammer, and crucial mission duty cycles. The primary objective of the cold flow testing was to simulate the RP propulsion system fluid flow operation through water flow testing and to obtain data for anchoring analytical models. The models will be used to predict the transient and steady state flow behaviors in the actual flight operations. All design and

  5. Hamiltonian methods of modeling and control of AC microgrids with spinning machines and inverters

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

    Matthews, Ronald C.; Weaver, Wayne W.; Robinett, Rush D.

    This study presents a novel approach to the modeling and control of AC microgrids that contain spinning machines, power electronic inverters and energy storage devices. The inverters in the system can adjust their frequencies and power angles very quickly, so the modeling focuses on establishing a common reference frequency and angle in the microgrid based on the spinning machines. From this dynamic model, nonlinear Hamiltonian surface shaping and power flow control method is applied and shown to stabilize. From this approach the energy flow in the system is used to show the energy storage device requirements and limitations for themore » system. This paper first describes the model for a single bus AC microgrid with a Hamiltonian control, then extends this model and control to a more general class of multiple bus AC microgrids. Finally, simulation results demonstrate the efficacy of the approach in stabilizing and optimization of the microgrid.« less

  6. Hamiltonian methods of modeling and control of AC microgrids with spinning machines and inverters

    DOE PAGES

    Matthews, Ronald C.; Weaver, Wayne W.; Robinett, Rush D.; ...

    2017-12-22

    This study presents a novel approach to the modeling and control of AC microgrids that contain spinning machines, power electronic inverters and energy storage devices. The inverters in the system can adjust their frequencies and power angles very quickly, so the modeling focuses on establishing a common reference frequency and angle in the microgrid based on the spinning machines. From this dynamic model, nonlinear Hamiltonian surface shaping and power flow control method is applied and shown to stabilize. From this approach the energy flow in the system is used to show the energy storage device requirements and limitations for themore » system. This paper first describes the model for a single bus AC microgrid with a Hamiltonian control, then extends this model and control to a more general class of multiple bus AC microgrids. Finally, simulation results demonstrate the efficacy of the approach in stabilizing and optimization of the microgrid.« less

  7. The Optimization Design of An AC-Electroosmotic Micro mixer

    NASA Astrophysics Data System (ADS)

    Wang, Yangyang; Suh, Yongkweon; Kang, Sangmo

    2007-11-01

    We propose the optimization design of an AC-electroosmotic micro-mixer, which is composed of a channel and a series of pairs of electrodes attached on the bottom wall in zigzag patterns. The AC electric field is applied to the electrodes so that a fluid flow takes place around the electrodes across the channel, thus contributing to the mixing of the fluid within the channel. We have performed numerical simulations by using a commercial code (CFX 10) to optimize the shape and pattern of the electrodes via the concept of mixing index. It is found that the best combination of two kinds of electrodes, which leads to good mixing performance, is not simply harmonic one. When the length ratio of the two kinds of electrodes closes to 2:1, we can get the best mixing effect. Furthermore, we will visualize the flow pattern and measure the velocity field with a PTV technique to validate the numerical simulations. In addition, the mixing pattern will be visualized via the experiment.

  8. Preparation of a new adsorbent from activated carbon and carbon nanofiber (AC/CNF) for manufacturing organic-vacbpour respirator cartridge

    PubMed Central

    2013-01-01

    In this study a composite of activated carbon and carbon nanofiber (AC/CNF) was prepared to improve the performance of activated carbon (AC) for adsorption of volatile organic compounds (VOCs) and its utilization for respirator cartridges. Activated carbon was impregnated with a nickel nitrate catalyst precursor and carbon nanofibers (CNF) were deposited directly on the AC surface using catalytic chemical vapor deposition. Deposited CNFs on catalyst particles in AC micropores, were activated by CO2 to recover the surface area and micropores. Surface and textural characterizations of the prepared composites were investigated using Brunauer, Emmett and Teller’s (BET) technique and electron microscopy respectively. Prepared composite adsorbent was tested for benzene, toluene and xylene (BTX) adsorption and then employed in an organic respirator cartridge in granular form. Adsorption studies were conducted by passing air samples through the adsorbents in a glass column at an adjustable flow rate. Finally, any adsorbed species not retained by the adsorbents in the column were trapped in a charcoal sorbent tube and analyzed by gas chromatography. CNFs with a very thin diameter of about 10-20 nm were formed uniformly on the AC/CNF. The breakthrough time for cartridges prepared with CO2 activated AC/CNF was 117 minutes which are significantly longer than for those cartridges prepared with walnut shell- based activated carbon with the same weight of adsorbents. This study showed that a granular form CO2 activated AC/CNF composite could be a very effective alternate adsorbent for respirator cartridges due to its larger adsorption capacities and lower weight. PMID:23369424

  9. AC electrokinetic manipulation of selenium nanoparticles for potential nanosensor applications

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

    Mahmoodi, Seyed Reza; Bayati, Marzieh, E-mail: m-bayati@tums.ac.ir; Hosseinirad, Somayeh

    2013-03-15

    Highlights: ► Se nanoparticles were synthesized using a reverse-microemulsion process. ► AC osmotic fluid flow repulses the particles from electrode edges. ► Dielectrophoretic force attracts the particles to electrode edges. ► Dielectrophoresis electrode showed non-ohmic behavior. ► The device can potentially be used as a nanosensor. - Abstract: We report the AC electrokinetic behavior of selenium (Se) nanoparticles for electrical characterization and possible application as micro/nano devices. selenium Se nanoparticles were successfully synthesized using a reverse-microemulsion process and investigated structurally using X-ray diffraction and transmission electron microscope. Interdigitated castellated ITO and non-castellated platinum electrodes were employed for manipulation of suspendedmore » materials in the fluid. Using ITO electrodes at low frequency limits resulted in deposition of Se particles on electrode surface. When Se particles exposed to platinum electrodes in the 10 Hz–1 kHz range and V {sub p−p}> 8, AC osmotic fluid flow repulses the particles from electrode edges. However, in 10 kHz–10 MHz range and V {sub p−p}> 5, dielectrophoretic force attracts the particles to electrode edges. As the Se particle concentration increased, the trapped Se particles were aligned along the electric field line and bridged the electrode gap. The device was characterized and can potentially be useful in making micro/nano electronic devices.« less

  10. Optimal Power Scheduling for a Medium Voltage AC/DC Hybrid Distribution Network

    DOE PAGES

    Zhu, Zhenshan; Liu, Dichen; Liao, Qingfen; ...

    2018-01-26

    With the great increase of renewable generation as well as the DC loads in the distribution network; DC distribution technology is receiving more attention; since the DC distribution network can improve operating efficiency and power quality by reducing the energy conversion stages. This paper presents a new architecture for the medium voltage AC/DC hybrid distribution network; where the AC and DC subgrids are looped by normally closed AC soft open point (ACSOP) and DC soft open point (DCSOP); respectively. The proposed AC/DC hybrid distribution systems contain renewable generation (i.e., wind power and photovoltaic (PV) generation); energy storage systems (ESSs); softmore » open points (SOPs); and both AC and DC flexible demands. An energy management strategy for the hybrid system is presented based on the dynamic optimal power flow (DOPF) method. The main objective of the proposed power scheduling strategy is to minimize the operating cost and reduce the curtailment of renewable generation while meeting operational and technical constraints. The proposed approach is verified in five scenarios. The five scenarios are classified as pure AC system; hybrid AC/DC system; hybrid system with interlinking converter; hybrid system with DC flexible demand; and hybrid system with SOPs. Results show that the proposed scheduling method can successfully dispatch the controllable elements; and that the presented architecture for the AC/DC hybrid distribution system is beneficial for reducing operating cost and renewable generation curtailment.« less

  11. Optimal Power Scheduling for a Medium Voltage AC/DC Hybrid Distribution Network

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

    Zhu, Zhenshan; Liu, Dichen; Liao, Qingfen

    With the great increase of renewable generation as well as the DC loads in the distribution network; DC distribution technology is receiving more attention; since the DC distribution network can improve operating efficiency and power quality by reducing the energy conversion stages. This paper presents a new architecture for the medium voltage AC/DC hybrid distribution network; where the AC and DC subgrids are looped by normally closed AC soft open point (ACSOP) and DC soft open point (DCSOP); respectively. The proposed AC/DC hybrid distribution systems contain renewable generation (i.e., wind power and photovoltaic (PV) generation); energy storage systems (ESSs); softmore » open points (SOPs); and both AC and DC flexible demands. An energy management strategy for the hybrid system is presented based on the dynamic optimal power flow (DOPF) method. The main objective of the proposed power scheduling strategy is to minimize the operating cost and reduce the curtailment of renewable generation while meeting operational and technical constraints. The proposed approach is verified in five scenarios. The five scenarios are classified as pure AC system; hybrid AC/DC system; hybrid system with interlinking converter; hybrid system with DC flexible demand; and hybrid system with SOPs. Results show that the proposed scheduling method can successfully dispatch the controllable elements; and that the presented architecture for the AC/DC hybrid distribution system is beneficial for reducing operating cost and renewable generation curtailment.« less

  12. ACS from development to operations

    NASA Astrophysics Data System (ADS)

    Caproni, Alessandro; Colomer, Pau; Jeram, Bogdan; Sommer, Heiko; Chiozzi, Gianluca; Mañas, Miguel M.

    2016-08-01

    The ALMA Common Software (ACS), provides the infrastructure of the distributed software system of ALMA and other projects. ACS, built on top of CORBA and Data Distribution Service (DDS) middleware, is based on a Component- Container paradigm and hides the complexity of the middleware allowing the developer to focus on domain specific issues. The transition of the ALMA observatory from construction to operations brings with it that ACS effort focuses primarily on scalability, stability and robustness rather than on new features. The transition came together with a shorter release cycle and a more extensive testing. For scalability, the most problematic area has been the CORBA notification service, used to implement the publisher subscriber pattern because of the asynchronous nature of the paradigm: a lot of effort has been spent to improve its stability and recovery from run time errors. The original bulk data mechanism, implemented using the CORBA Audio/Video Streaming Service, showed its limitations and has been replaced with a more performant and scalable DDS implementation. Operational needs showed soon the difference between releases cycles for Online software (i.e. used during observations) and Offline software, which requires much more frequent releases. This paper attempts to describe the impact the transition from construction to operations had on ACS, the solution adopted so far and a look into future evolution.

  13. 42 CFR 84.93 - Gas flow test; open-circuit apparatus.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 42 Public Health 1 2011-10-01 2011-10-01 false Gas flow test; open-circuit apparatus. 84.93...-Contained Breathing Apparatus § 84.93 Gas flow test; open-circuit apparatus. (a) A static-flow test will be performed on all open-circuit apparatus. (b) The flow from the apparatus shall be greater than 200 liters...

  14. 42 CFR 84.93 - Gas flow test; open-circuit apparatus.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 42 Public Health 1 2010-10-01 2010-10-01 false Gas flow test; open-circuit apparatus. 84.93...-Contained Breathing Apparatus § 84.93 Gas flow test; open-circuit apparatus. (a) A static-flow test will be performed on all open-circuit apparatus. (b) The flow from the apparatus shall be greater than 200 liters...

  15. Improved transistorized AC motor controller for battery powered urban electric passenger vehicles

    NASA Technical Reports Server (NTRS)

    Peak, S. C.

    1982-01-01

    An ac motor controller for an induction motor electric vehicle drive system was designed, fabricated, tested, evaluated, and cost analyzed. A vehicle performance analysis was done to establish the vehicle tractive effort-speed requirements. These requirements were then converted into a set of ac motor and ac controller requirements. The power inverter is a three-phase bridge using power Darlington transistors. The induction motor was optimized for use with an inverter power source. The drive system has a constant torque output to base motor speed and a constant horsepower output to maximum speed. A gear shifting transmission is not required. The ac controller was scaled from the base 20 hp (41 hp peak) at 108 volts dec to an expanded horsepower and battery voltage range. Motor reversal was accomplished by electronic reversal of the inverter phase sequence. The ac controller can also be used as a boost chopper battery charger. The drive system was tested on a dynamometer and results are presented. The current-controlled pulse width modulation control scheme yielded improved motor current waveforms. The ac controller favors a higher system voltage.

  16. Power flow controller with a fractionally rated back-to-back converter

    DOEpatents

    Divan, Deepakraj M.; Kandula, Rajendra Prasad; Prasai, Anish

    2016-03-08

    A power flow controller with a fractionally rated back-to-back (BTB) converter is provided. The power flow controller provide dynamic control of both active and reactive power of a power system. The power flow controller inserts a voltage with controllable magnitude and phase between two AC sources at the same frequency; thereby effecting control of active and reactive power flows between the two AC sources. A transformer may be augmented with a fractionally rated bi-directional Back to Back (BTB) converter. The fractionally rated BTB converter comprises a transformer side converter (TSC), a direct-current (DC) link, and a line side converter (LSC). By controlling the switches of the BTB converter, the effective phase angle between the two AC source voltages may be regulated, and the amplitude of the voltage inserted by the power flow controller may be adjusted with respect to the AC source voltages.

  17. How is flow experienced and by whom? Testing flow among occupations.

    PubMed

    Llorens, Susana; Salanova, Marisa; Rodríguez, Alma M

    2013-04-01

    The aims of this paper are to test (1) the factorial structure of the frequency of flow experience at work; (2) the flow analysis model in work settings by differentiating the frequency of flow and the frequency of its prerequisites; and (3) whether there are significant differences in the frequency of flow experience depending on the occupation. A retrospective study among 957 employees (474 tile workers and 483 secondary school teachers) using multigroup confirmatory factorial analyses and multiple analyses of variance suggested that on the basis of the flow analysis model in work settings, (1) the frequency of flow experience has a two-factor structure (enjoyment and absorption); (2) the frequency of flow experience at work is produced when both challenge and skills are high and balanced; and (3) secondary school teachers experience flow more frequently than tile workers. Copyright © 2012 John Wiley & Sons, Ltd.

  18. Oscillating-flow loss test results in rectangular heat exchanger passages

    NASA Technical Reports Server (NTRS)

    Wood, J. Gary

    1991-01-01

    Test results of oscillating flow losses in rectangular heat exchanger passages of various aspect ratios are given. This work was performed in support of the design of a free-piston Stirling engine (FPSE) for a dynamic space power conversion system. Oscillating flow loss testing was performed using an oscillating flow rig, which was based on a variable stroke and variable frequency linear drive motor. Tests were run over a range of oscillating flow parameters encompassing the flow regimes of the proposed engine design. Test results are presented in both tabular and graphical form and are compared against analytical predictions.

  19. Obtaining continuous BrAC/BAC estimates in the field: A hybrid system integrating transdermal alcohol biosensor, Intellidrink smartphone app, and BrAC Estimator software tools.

    PubMed

    Luczak, Susan E; Hawkins, Ashley L; Dai, Zheng; Wichmann, Raphael; Wang, Chunming; Rosen, I Gary

    2018-08-01

    Biosensors have been developed to measure transdermal alcohol concentration (TAC), but converting TAC into interpretable indices of blood/breath alcohol concentration (BAC/BrAC) is difficult because of variations that occur in TAC across individuals, drinking episodes, and devices. We have developed mathematical models and the BrAC Estimator software for calibrating and inverting TAC into quantifiable BrAC estimates (eBrAC). The calibration protocol to determine the individualized parameters for a specific individual wearing a specific device requires a drinking session in which BrAC and TAC measurements are obtained simultaneously. This calibration protocol was originally conducted in the laboratory with breath analyzers used to produce the BrAC data. Here we develop and test an alternative calibration protocol using drinking diary data collected in the field with the smartphone app Intellidrink to produce the BrAC calibration data. We compared BrAC Estimator software results for 11 drinking episodes collected by an expert user when using Intellidrink versus breath analyzer measurements as BrAC calibration data. Inversion phase results indicated the Intellidrink calibration protocol produced similar eBrAC curves and captured peak eBrAC to within 0.0003%, time of peak eBrAC to within 18min, and area under the eBrAC curve to within 0.025% alcohol-hours as the breath analyzer calibration protocol. This study provides evidence that drinking diary data can be used in place of breath analyzer data in the BrAC Estimator software calibration procedure, which can reduce participant and researcher burden and expand the potential software user pool beyond researchers studying participants who can drink in the laboratory. Copyright © 2017. Published by Elsevier Ltd.

  20. Flow Visualization of Liquid Hydrogen Line Chilldown Tests

    NASA Technical Reports Server (NTRS)

    Rame, Enrique; Hartwig, Jason W.; McQuillen John B.

    2014-01-01

    We present experimental measurements of wall and fluid temperature during chill-down tests of a warm cryogenic line with liquid hydrogen. Synchronized video and fluid temperature measurements are used to interpret stream temperature profiles versus time. When cold liquid hydrogen starts to flow into the warm line, a sequence of flow regimes, spanning from all-vapor at the outset to bubbly with continuum liquid at the end can be observed at a location far downstream of the cold inlet. In this paper we propose interpretations to the observed flow regimes and fluid temperature histories for two chilldown methods, viz. trickle (i.e. continuous) flow and pulse flow. Calculations of heat flux from the wall to the fluid versus wall temperature indicate the presence of the transition/nucleate boiling regimes only. The present tests, run at typical Reynolds numbers of approx O(10 (exp 5)), are in sharp contrast to similar tests conducted at lower Reynolds numbers where a well-defined film boiling region is observed.

  1. AC power generation from microbial fuel cells

    NASA Astrophysics Data System (ADS)

    Lobo, Fernanda Leite; Wang, Heming; Forrestal, Casey; Ren, Zhiyong Jason

    2015-11-01

    Microbial fuel cells (MFCs) directly convert biodegradable substrates to electricity and carry good potential for energy-positive wastewater treatment. However, the low and direct current (DC) output from MFC is not usable for general electronics except small sensors, yet commercial DC-AC converters or inverters used in solar systems cannot be directly applied to MFCs. This study presents a new DC-AC converter system for MFCs that can generate alternating voltage in any desired frequency. Results show that AC power can be easily achieved in three different frequencies tested (1, 10, 60 Hz), and no energy storage layer such as capacitors was needed. The DC-AC converter efficiency was higher than 95% when powered by either individual MFCs or simple MFC stacks. Total harmonic distortion (THD) was used to investigate the quality of the energy, and it showed that the energy could be directly usable for linear electronic loads. This study shows that through electrical conversion MFCs can be potentially used in household electronics for decentralized off-grid communities.

  2. FLIT: Flowing LIquid metal Torus

    NASA Astrophysics Data System (ADS)

    Kolemen, Egemen; Majeski, Richard; Maingi, Rajesh; Hvasta, Michael

    2017-10-01

    The design and construction of FLIT, Flowing LIquid Torus, at PPPL is presented. FLIT focuses on a liquid metal divertor system suitable for implementation and testing in present-day fusion systems, such as NSTX-U. It is designed as a proof-of-concept fast-flowing liquid metal divertor that can handle heat flux of 10 MW/m2 without an additional cooling system. The 72 cm wide by 107 cm tall torus system consisting of 12 rectangular coils that give 1 Tesla magnetic field in the center and it can operate for greater than 10 seconds at this field. Initially, 30 gallons Galinstan (Ga-In-Sn) will be recirculated using 6 jxB pumps and flow velocities of up to 10 m/s will be achieved on the fully annular divertor plate. FLIT is designed as a flexible machine that will allow experimental testing of various liquid metal injection techniques, study of flow instabilities, and their control in order to prove the feasibility of liquid metal divertor concept for fusion reactors. FLIT: Flowing LIquid metal Torus. This work is supported by the US DOE Contract No. DE-AC02-09CH11466.

  3. System and method for monitoring and controlling stator winding temperature in a de-energized AC motor

    DOEpatents

    Lu, Bin [Kenosha, WI; Luebke, Charles John [Sussex, WI; Habetler, Thomas G [Snellville, GA; Zhang, Pinjia [Atlanta, GA; Becker, Scott K [Oak Creek, WI

    2011-12-27

    A system and method for measuring and controlling stator winding temperature in an AC motor while idling is disclosed. The system includes a circuit having an input connectable to an AC source and an output connectable to an input terminal of a multi-phase AC motor. The circuit further includes a plurality of switching devices to control current flow and terminal voltages in the multi-phase AC motor and a controller connected to the circuit. The controller is configured to activate the plurality of switching devices to create a DC signal in an output of the motor control device corresponding to an input to the multi-phase AC motor, determine or estimate a stator winding resistance of the multi-phase AC motor based on the DC signal, and estimate a stator temperature from the stator winding resistance. Temperature can then be controlled and regulated by DC injection into the stator windings.

  4. Flight Tests of a Supersonic Natural Laminar Flow Airfoil

    NASA Technical Reports Server (NTRS)

    Frederick, M. A.; Banks, D. W.; Garzon, G. A.; Matisheck, J. R.

    2014-01-01

    A flight test campaign of a supersonic natural laminar flow airfoil has been recently completed. The test surface was an 80-inch (203 cm) chord and 40-inch (102 cm) span article mounted on the centerline store location of an F-15B airplane. The wing was designed with a leading edge sweep of effectively 0 deg to minimize boundary layer crossflow. The test article surface was coated with an insulating material to avoid significant heat transfer to and from the test article structure to maintain a quasi-adiabatic wall. An aircraft-mounted infrared camera system was used to determine boundary layer transition and the extent of laminar flow. The tests were flown up to Mach 2.0 and chord Reynolds numbers in excess of 30 million. The objectives of the tests were to determine the extent of laminar flow at high Reynolds numbers and to determine the sensitivity of the flow to disturbances. Both discrete (trip dots) and 2-D disturbances (forward-facing steps) were tested. A series of oblique shocks, of yet unknown origin, appeared on the surface, which generated sufficient crossflow to affect transition. Despite the unwanted crossflow, the airfoil performed well. The results indicate the sensitivity of the flow to the disturbances, which can translate into manufacturing tolerances, were similar to that of subsonic natural laminar flow wings.

  5. Design principle for improved three-dimensional ac electro-osmotic pumps.

    PubMed

    Burch, Damian; Bazant, Martin Z

    2008-05-01

    Three-dimensional (3D) ac electro-osmotic (ACEO) pumps have recently been developed that are much faster and more robust than previous planar designs. The basic idea is to create a "fluid conveyor belt" by placing opposing ACEO slip velocities at different heights. Current designs involve electrodes with electroplated steps, whose heights have been optimized in simulations and experiments. Here, we consider changing the boundary conditions-rather than the geometry-and predict that flow rates can be further doubled by fabricating 3D features with nonpolarizable materials. This amplifies the fluid conveyor belt by removing opposing flows on the vertical surfaces, and it increases the slip velocities that drive the flow.

  6. Study on emergency power control strategy for AC/DC hybrid power system containing VSC-HVDC

    NASA Astrophysics Data System (ADS)

    Liu, Lin; Hu, Zhenda; Ye, Rong; Lin, Zhangsui; Yang, Xiaodong; Yi, Yang

    2018-04-01

    This paper presents a comprehensive emergency power control strategy for AC/DC hybrid power systems containing VSC-HVDC. Firstly, the paper analyzes the power support of the VSC-HVDC to the AC lines using the Power Transferring Relativity Factor (PTRF). Then the power adjustment of the VSC-HVDC in several different circumstances are calculated. Finally, the online power control strategies of VSC-HVDC are designed, which could rapidly control the power of the VSC-HVDC, keeping the power flow of AC lines below the upper limit. Furthermore, the strategy is proven to be effective by the simulations with EMTDC/PSCAD.

  7. Flight Tests of a Supersonic Natural Laminar Flow Airfoil

    NASA Technical Reports Server (NTRS)

    Frederick, Michael A.; Banks, Daniel W.; Garzon, G. A.; Matisheck, J. R.

    2015-01-01

    A flight-test campaign of a supersonic natural laminar flow airfoil has been recently completed. The test surface was an 80-inch (203 cm) chord and 40-inch (102 cm) span article mounted on the centerline store location of an F-15B airplane (McDonnell Douglas Corporation, now The Boeing Company, Chicago, Illinois). The test article was designed with a leading edge sweep of effectively 0 deg to minimize boundary layer crossflow. The test article surface was coated with an insulating material to avoid significant heat transfer to and from the test article structure to maintain a quasi-adiabatic wall. An aircraft-mounted infrared camera system was used to determine boundary layer transition and the extent of laminar flow. The tests were flown up to Mach 2.0 and chord Reynolds numbers in excess of 30 million. The objectives of the tests were to determine the extent of laminar flow at high Reynolds numbers and to determine the sensitivity of the flow to disturbances. Both discrete (trip dots) and 2-D disturbances (forward-facing steps) were tested. A series of oblique shocks, of yet unknown origin, appeared on the surface, which generated sufficient crossflow to affect transition. Despite the unwanted crossflow, the airfoil performed well. The results indicate the sensitivity of the flow to the disturbances, which can translate into manufacturing tolerances, were similar to that of subsonic natural laminar flow wings.

  8. Promising efficacy of novel BTK inhibitor AC0010 in mantle cell lymphoma.

    PubMed

    Yan, Xiao; Zhou, Yile; Huang, Shujuan; Li, Xia; Yu, Mengxia; Huang, Jiansong; Wang, Jinghan; Ma, Zhixin; Jin, Jingrui; Pan, Jiajia; Li, Chenying; Li, Fenglin; Jin, Jie

    2018-04-01

    We researched into the effect and mechanism of AC0010, a novel BTK inhibitor, in MCL, and compared its efficacy and safety with Ibrutinib to develop a preclinical study for the future therapy of MCL. MTS assay was used to detect the growth inhibition caused by AC0010 and Ibrutinib, respectively, in MCL cell lines (Jeko-1 and JVM-2), primary MCL cells, and normal peripheral lymphocytes. Apoptosis of Jeko-1 and JVM-2 after exposure into AC0010 and Ibrutinib was conducted by flow cytometry; the expression of apoptosis-related proteins was checked by Western blot. q-PCR and Western blot were applied to examine the expression of BTK and p-BTK at mRNA and protein level as well as the BTK-ralated signaling pathways. MCL xenograft was developed to testify the efficacy and safety of AC0010 in vivo. In contrast with Ibrutinib, AC0010 proved to be more toxic to MCL cells in vitro (p < 0.01) with no augment in cytotoxicity to normal peripheral lymphocytes, and it can induce obvious apoptosis in MCL cell lines (p < 0.01) through caspase family and Bcl-2 family. AC0010 at 300 mg/kg can prolong the survival rate in MCL xenograft (p < 0.01). The phosphorylation of BTK is inhibited by AC0010 following simultaneously inhibition of BCR-BTK and PI3K/AKT signaling pathway in MCL cells. AC0010 is a novel BTK inhibitor of great efficacy and safety in MCL.

  9. ARC-1978-AC78-1040-172

    NASA Image and Video Library

    1978-11-14

    Lockheed YO-3A (USA 69-18010 NASA 718) A/C & BELL COBRA HELICOPTER FLIGHT & GROUND TESTS AT EDWARDS AIR FORCE BASE. Rotorcraft Research. NASA SP-1998-3300 Flight Research at Ames: 57 Years of Development and Validation of Aeronautical Technology Fig. 143

  10. Missile Flight Control Using micro-Actuated Flow Effectors - Review of Fiscal Year 2005/2006 Progress

    DTIC Science & Technology

    2006-08-01

    be developed. A common analysis model covering the aerodynamic-flow effector interaction, the compliant mechanism-SMA dynamics and the control...additional CFD analysis for the finless DRDC-B1AC2R between 15 deg. to 20 deg. to determine where the peak side force is situated. Compare pressure...Carry out CFD study on DRDC-B1AC2R with fins. Decide on analysis matrix. Coordinate with wind tunnel test matrix. Action: DRDC-nh Y0405-7. Decide

  11. Assessment of the National Transonic Facility for Laminar Flow Testing

    NASA Technical Reports Server (NTRS)

    Crouch, Jeffrey D.; Sutanto, Mary I.; Witkowski, David P.; Watkins, A. Neal; Rivers, Melissa B.; Campbell, Richard L.

    2010-01-01

    A transonic wing, designed to accentuate key transition physics, is tested at cryogenic conditions at the National Transonic Facility at NASA Langley. The collaborative test between Boeing and NASA is aimed at assessing the facility for high-Reynolds number testing of configurations with significant regions of laminar flow. The test shows a unit Reynolds number upper limit of 26 M/ft for achieving natural transition. At higher Reynolds numbers turbulent wedges emanating from the leading edge bypass the natural transition process and destroy the laminar flow. At lower Reynolds numbers, the transition location is well correlated with the Tollmien-Schlichting-wave N-factor. The low-Reynolds number results suggest that the flow quality is acceptable for laminar flow testing if the loss of laminar flow due to bypass transition can be avoided.

  12. 42 CFR 84.94 - Gas flow test; closed-circuit apparatus.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 42 Public Health 1 2011-10-01 2011-10-01 false Gas flow test; closed-circuit apparatus. 84.94...-Contained Breathing Apparatus § 84.94 Gas flow test; closed-circuit apparatus. (a) Where oxygen is supplied... rated service time of the apparatus. (b) Where constant flow is used in conjunction with demand flow...

  13. 42 CFR 84.94 - Gas flow test; closed-circuit apparatus.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 42 Public Health 1 2010-10-01 2010-10-01 false Gas flow test; closed-circuit apparatus. 84.94...-Contained Breathing Apparatus § 84.94 Gas flow test; closed-circuit apparatus. (a) Where oxygen is supplied... rated service time of the apparatus. (b) Where constant flow is used in conjunction with demand flow...

  14. Oscillating flow loss test results in Stirling engine heat exchangers

    NASA Technical Reports Server (NTRS)

    Koester, G.; Howell, S.; Wood, G.; Miller, E.; Gedeon, D.

    1990-01-01

    The results are presented for a test program designed to generate a database of oscillating flow loss information that is applicable to Stirling engine heat exchangers. The tests were performed on heater/cooler tubes of various lengths and entrance/exit configurations, on stacked and sintered screen regenerators of various wire diameters and on Brunswick and Metex random fiber regenerators. The test results were performed over a range of oscillating flow parameters consistent with Stirling engine heat exchanger experience. The tests were performed on the Sunpower oscillating flow loss rig which is based on a variable stroke and variable frequency linear drive motor. In general, the results are presented by comparing the measured oscillating flow losses to the calculated flow losses. The calculated losses are based on the cycle integration of steady flow friction factors and entrance/exit loss coefficients.

  15. The ac propulsion system for an electric vehicle, phase 1

    NASA Astrophysics Data System (ADS)

    Geppert, S.

    1981-08-01

    A functional prototype of an electric vehicle ac propulsion system was built consisting of a 18.65 kW rated ac induction traction motor, pulse width modulated (PWM) transistorized inverter, two speed mechanically shifted automatic transmission, and an overall drive/vehicle controller. Design developmental steps, and test results of individual components and the complex system on an instrumented test frame are described. Computer models were developed for the inverter, motor and a representative vehicle. A preliminary reliability model and failure modes effects analysis are given.

  16. The ac propulsion system for an electric vehicle, phase 1

    NASA Technical Reports Server (NTRS)

    Geppert, S.

    1981-01-01

    A functional prototype of an electric vehicle ac propulsion system was built consisting of a 18.65 kW rated ac induction traction motor, pulse width modulated (PWM) transistorized inverter, two speed mechanically shifted automatic transmission, and an overall drive/vehicle controller. Design developmental steps, and test results of individual components and the complex system on an instrumented test frame are described. Computer models were developed for the inverter, motor and a representative vehicle. A preliminary reliability model and failure modes effects analysis are given.

  17. Wet Flow Test at Launch Complex 39B

    NASA Image and Video Library

    2017-12-20

    About 450,000 gallons of water flowed at high speed from a holding tank through new and modified piping and valves, the flame trench, flame deflector nozzles and mobile launcher interface risers during a wet flow test at Launch Pad 39B at NASA's Kennedy Space Center in Florida. At peak flow, the water reached about 100 feet in the air above the pad surface. The test was a milestone to confirm and baseline the performance of the Ignition Overpressure/Sound Suppression system. During launch of NASA's Space Launch System rocket and Orion spacecraft, the high-speed water flow will help protect the vehicle from the extreme acoustic and temperature environment during ignition and liftoff.

  18. Catalytic ozonation of dimethyl phthalate and chlorination disinfection by-product precursors over Ru/AC.

    PubMed

    Wang, Jianbing; Zhou, Yunrui; Zhu, Wanpeng; He, Xuwen

    2009-07-15

    Catalytic ozonation of dimethyl phthalate (DMP) in aqueous solution (5mg/L) under various reactions was performed to examine the effect of catalyst dosage, catalyst particle size, ozone dosage, and gas flow rate on the mineralization of DMP. The mineralization of DMP can be achieved via ozonation and the presence of Ru/AC could greatly accelerate the mineralization rate of DMP in ozonation process. In the continuous experiment of the Ru/AC catalyzed ozonation of DMP, total organic carbon (TOC) removals were kept stable around 75% during 42 h reaction. No leaching of ruthenium was observed in the treated water samples. The treatment of natural water using Ru/AC+O(3), Ru/AC+O(2) and ozonation alone was studied. In the Ru/AC+O(3) process, TOC removals, the reductions of the haloacetic acid formation potentials (HAAFPs), and the reductions of the trihalomethane formation potentials (THMFPs) of 11 water samples were 22-44%, 39-61% and 50-65%, respectively. Ru/AC+O(3) process was much more effective than ozonation alone for TOC removal and the reduction of disinfection by-product formation potential (DBPFP) in the treatment of natural water. It is a promising water treatment technology.

  19. Low Offset AC Correlator.

    DTIC Science & Technology

    This patent describes a low offset AC correlator avoids DC offset and low frequency noise by frequency operating the correlation signal so that low...noise, low level AC amplification can be substituted for DC amplification. Subsequently, the high level AC signal is demodulated to a DC level. (Author)

  20. Research notes : AC/CRC adjacent lane surfacing.

    DOT National Transportation Integrated Search

    1991-10-01

    Asphaltic Concrete (AC) and Portland Cement Concrete (PCC) are common roadway materials used in Oregon. In a recent construction project, Poverty Flats - Mecham Section, the Oregon State Highway Division (OSHD) designed a "test section" consisting of...

  1. Design principle for improved three-dimensional ac electro-osmotic pumps

    NASA Astrophysics Data System (ADS)

    Burch, Damian; Bazant, Martin Z.

    2008-05-01

    Three-dimensional (3D) ac electro-osmotic (ACEO) pumps have recently been developed that are much faster and more robust than previous planar designs. The basic idea is to create a “fluid conveyor belt” by placing opposing ACEO slip velocities at different heights. Current designs involve electrodes with electroplated steps, whose heights have been optimized in simulations and experiments. Here, we consider changing the boundary conditions—rather than the geometry—and predict that flow rates can be further doubled by fabricating 3D features with nonpolarizable materials. This amplifies the fluid conveyor belt by removing opposing flows on the vertical surfaces, and it increases the slip velocities that drive the flow.

  2. Charging in the ac Conductance of a Double Barrier Resonant Tunneling Structure

    NASA Technical Reports Server (NTRS)

    Anantram, M. P.; Saini, Subhash (Technical Monitor)

    1998-01-01

    There have been many studies of the linear response ac conductance of a double barrier resonant tunneling structure (DBRTS), both at zero and finite dc biases. While these studies are important, they fail to self consistently include the effect of the time dependent charge density in the well. In this paper, we calculate the ac conductance at both zero and finite do biases by including the effect of the time dependent charge density in the well in a self consistent manner. The charge density in the well contributes to both the flow of displacement currents in the contacts and the time dependent potential in the well. We find that including these effects can make a significant difference to the ac conductance and the total ac current is not equal to the simple average of the non-selfconsistently calculated conduction currents in the two contacts. This is illustrated by comparing the results obtained with and without the effect of the time dependent charge density included correctly. Some possible experimental scenarios to observe these effects are suggested.

  3. Theoretical prediction of fast 3D AC electro-osmotic pumps.

    PubMed

    Bazant, Martin Z; Ben, Yuxing

    2006-11-01

    AC electro-osmotic (ACEO) pumps in microfluidics currently involve planar electrode arrays, but recent work on the underlying phenomenon of induced-charge electro-osmosis (ICEO) suggests that three-dimensional (3D) geometries may be exploited to achieve faster flows. In this paper, we present some new design principles for periodic 3D ACEO pumps, such as the "fluid conveyor belt" of ICEO flow over a stepped electrode array. Numerical simulations of these designs (using the standard low-voltage model) predict flow rates almost twenty times faster than existing planar ACEO pumps, for the same applied voltage and minimum feature size. These pumps may enable new portable or implantable lab-on-a-chip devices, since rather fast (mm s(-1)), tuneable flows should be attainable with battery voltages (<10 V).

  4. Flow-Field Survey in the Test Region of the SR-71 Aircraft Test Bed Configuration

    NASA Technical Reports Server (NTRS)

    Mizukami, Masashi; Jones, Daniel; Weinstock, Vladimir D.

    2000-01-01

    A flat plate and faired pod have been mounted on a NASA SR-71A aircraft for use as a supersonic flight experiment test bed. A test article can be placed on the flat plate; the pod can contain supporting systems. A series of test flights has been conducted to validate this test bed configuration. Flight speeds to a maximum of Mach 3.0 have been attained. Steady-state sideslip maneuvers to a maximum of 2 deg have been conducted, and the flow field in the test region has been surveyed. Two total-pressure rakes, each with two flow-angle probes, have been placed in the expected vicinity of an experiment. Static-pressure measurements have been made on the flat plate. At subsonic and low supersonic speeds with no sideslip, the flow in the surveyed region is quite uniform. During sideslip maneuvers, localized flow distortions impinge on the test region. Aircraft sideslip does not produce a uniform sidewash over the test region. At speeds faster than Mach 1.5, variable-pressure distortions were observed in the test region. Boundary-layer thickness on the flat plate at the rake was less than 2.1 in. For future experiments, a more focused and detailed flow-field survey than this one would be desirable.

  5. Influences of Cry1Ac broccoli on larval survival and oviposition of diamondback moth.

    PubMed

    Yi, Dengxia; Cui, Shusong; Yang, Limei; Fang, Zhiyuan; Liu, Yumei; Zhuang, Mu; Zhang, Yangyong

    2015-01-01

    Larval survival and oviposition behavior of three genotypes of diamondback moth, Plutella xylostella L. (Lepidoptera: Plutellidae), (homozygous Cry1Ac-susceptibile, Cry1Ac-resistant, and their F1 hybrids), on transgenic Bacillus thuringiensis (Bt) broccoli expressing different levels of Cry1Ac protein were evaluated in laboratory. These Bt broccoli lines were designated as relative low, medium, and high, respectively, according to the Cry1Ac content. Untransformed brocccoli plants were used as control. Larval survival of diamondback moth on non-Bt leaves was not significantly different among the three genotypes. The Cry1Ac-resistant larvae could survive on the low level of Bt broccoli plants, while Cry1Ac-susceptible and F1 larvae could not survive on them. The three genotypes of P. xylostella larvae could not survive on medium and high levels of Bt broccoli. In oviposition choice tests, there was no significant difference in the number of eggs laid by the three P. xylostella genotypes among different Bt broccoli plants. The development of Cry1Ac-susceptible and Cry1Ac-resistant P. xylostella on intact Bt plants was also tested in greenhouse. All susceptible P. xylostella larvae died on all Bt plants, while resistant larvae could survive on broccoli, which expresses low Cry1Ac protein under greenhouse conditions. The results of the greenhouse trials were similar to that of laboratory tests. This study indicated that high dose of Bt toxins in broccoli cultivars or germplasm lines is required for effective resistance management. © The Author 2015. Published by Oxford University Press on behalf of the Entomological Society of America.

  6. Alternating current (AC) iontophoretic transport across human epidermal membrane: effects of AC frequency and amplitude.

    PubMed

    Yan, Guang; Xu, Qingfang; Anissimov, Yuri G; Hao, Jinsong; Higuchi, William I; Li, S Kevin

    2008-03-01

    As a continuing effort to understand the mechanisms of alternating current (AC) transdermal iontophoresis and the iontophoretic transport pathways in the stratum corneum (SC), the objectives of the present study were to determine the interplay of AC frequency, AC voltage, and iontophoretic transport of ionic and neutral permeants across human epidermal membrane (HEM) and use AC as a means to characterize the transport pathways. Constant AC voltage iontophoresis experiments were conducted with HEM in 0.10 M tetraethyl ammonium pivalate (TEAP). AC frequencies ranging from 0.0001 to 25 Hz and AC applied voltages of 0.5 and 2.5 V were investigated. Tetraethyl ammonium (TEA) and arabinose (ARA) were the ionic and neutral model permeants, respectively. In data analysis, the logarithm of the permeability coefficients of HEM for the model permeants was plotted against the logarithm of the HEM electrical resistance for each AC condition. As expected, linear correlations between the logarithms of permeability coefficients and the logarithms of resistances of HEM were observed, and the permeability data were first normalized and then compared at the same HEM electrical resistance using these correlations. Transport enhancement of the ionic permeant was significantly larger than that of the neutral permeant during AC iontophoresis. The fluxes of the ionic permeant during AC iontophoresis of 2.5 V in the frequency range from 5 to 1,000 Hz were relatively constant and were approximately 4 times over those of passive transport. When the AC frequency decreased from 5 to 0.001 Hz at 2.5 V, flux enhancement increased to around 50 times over passive transport. While the AC frequency for achieving the full effect of iontophoretic enhancement at low AC frequency was lower than anticipated, the frequency for approaching passive diffusion transport at high frequency was higher than expected from the HEM morphology. These observations are consistent with a transport model of multiple

  7. Electroporation of cells using EM induction of ac fields by a magnetic stimulator

    NASA Astrophysics Data System (ADS)

    Chen, C.; Evans, J. A.; Robinson, M. P.; Smye, S. W.; O'Toole, P.

    2010-02-01

    This paper describes a method of effectively electroporating mammalian cell membranes with pulsed alternating-current (ac) electric fields at field strengths of 30-160 kV m-1. Although many in vivo electroporation protocols entail applying square wave or monotonically decreasing pulses via needles or electrode plates, relatively few have explored the use of pulsed ac fields. Following our previous study, which established the effectiveness of ac fields for electroporating cell membranes, a primary/secondary coil system was constructed to produce sufficiently strong electric fields by electromagnetic induction. The primary coil was formed from the applicator of an established transcranial magnetic stimulation (TMS) system, while the secondary coil was a purpose-built device of a design which could eventually be implanted into tissue. The effects of field strength, pulse interval and cumulative exposure time were investigated using microscopy and flow cytometry. Results from experiments on concentrated cell suspensions showed an optimized electroporation efficiency of around 50%, demonstrating that electroporation can be practicably achieved by inducing such pulsed ac fields. This finding confirms the possibility of a wide range of in vivo applications based on magnetically coupled ac electroporation.

  8. Quantifiable Lateral Flow Assay Test Strips

    NASA Technical Reports Server (NTRS)

    2003-01-01

    As easy to read as a home pregnancy test, three Quantifiable Lateral Flow Assay (QLFA) strips used to test water for E. coli show different results. The brightly glowing control line on the far right of each strip indicates that all three tests ran successfully. But the glowing test line on the middle left and bottom strips reveal their samples were contaminated with E. coli bacteria at two different concentrations. The color intensity correlates with concentration of contamination.

  9. Hybrid AC-High Voltage DC Grid Stability and Controls

    NASA Astrophysics Data System (ADS)

    Yu, Jicheng

    The growth of energy demands in recent years has been increasing faster than the expansion of transmission facility construction. This tendency cooperating with the continuous investing on the renewable energy resources drives the research, development, and construction of HVDC projects to create a more reliable, affordable, and environmentally friendly power grid. Constructing the hybrid AC-HVDC grid is a significant move in the development of the HVDC techniques; the form of dc system is evolving from the point-to-point stand-alone dc links to the embedded HVDC system and the multi-terminal HVDC (MTDC) system. The MTDC is a solution for the renewable energy interconnections, and the MTDC grids can improve the power system reliability, flexibility in economic dispatches, and converter/cable utilizing efficiencies. The dissertation reviews the HVDC technologies, discusses the stability issues regarding the ac and HVDC connections, proposes a novel power oscillation control strategy to improve system stability, and develops a nonlinear voltage droop control strategy for the MTDC grid. To verify the effectiveness the proposed power oscillation control strategy, a long distance paralleled AC-HVDC transmission test system is employed. Based on the PSCAD/EMTDC platform simulation results, the proposed power oscillation control strategy can improve the system dynamic performance and attenuate the power oscillations effectively. To validate the nonlinear voltage droop control strategy, three droop controls schemes are designed according to the proposed nonlinear voltage droop control design procedures. These control schemes are tested in a hybrid AC-MTDC system. The hybrid AC-MTDC system, which is first proposed in this dissertation, consists of two ac grids, two wind farms and a five-terminal HVDC grid connecting them. Simulation studies are performed in the PSCAD/EMTDC platform. According to the simulation results, all the three design schemes have their unique salient

  10. NCV Flow Diagnostic Test Results

    NASA Technical Reports Server (NTRS)

    Cappuccio, Mina

    1999-01-01

    There were two objectives for this test. First, was to assess the reasons why there is approximately 1.5 drag counts (cts) discrepancy between measured and computed drag improvement of the Non-linear Cruise Validation (NCV) over the Technology Concept Airplane (TCA) wing body (WB) configurations. The Navier-Stokes (N-S) pre-test predictions from Boeing Commercial Airplane Group (BCAG) show 4.5 drag cts of improvement for NCV over TCA at a lift coefficient (CL) of 0. I at Mach 2.4. The pre-test predictions from Boeing Phantom Works - Long Beach, BPW-LB, show 3.75 drag cts of improvement. BCAG used OVERFLOW and BPW-LB used CFL3D. The first test entry to validate the improvement was held at the NASA Langley Research Center (LARC) UPV;T, test number 1687. The experimental results showed that the drag improvement was only 2.6 cts, not accounting for laminar run and trip drag. This is approximately 1.5 cts less than predicted computationally. In addition to the low Reynolds Number (RN) test, there was a high RN test in the Boeing Supersonic Wind Tunnel (BSWT) of NCV and TCA. BSV@T test 647 showed that the drag improvement of NCV over TCA was also 2.6 cts, but this did account for laminar run and trip drag. Every effort needed to be done to assess if the improvement measured in LaRC UPWT and BSWT was correct. The second objective, once the first objective was met, was to assess the performance increment of NCV over TCA accounting for the associated laminar run and trip drag corrections in LaRC UPWT. We know that the configurations tested have laminar flow on portions of the wing and have trip drag due to the mechanisms used to force the flow to go from laminar to turbulent aft of the transition location.

  11. AC-Induced Bias Potential Effect on Corrosion of Steels

    DTIC Science & Technology

    2009-02-05

    induction, variable conduction Experimental Setup Super- martensitic stainless steel composition Analysis: C Mn Si Cr Ni Mo Cu N Typical 13 Cr ɘ.01 0.6... stainless steel used in pipelines. •Low carbon (ɘ.01): allows the formation of a “soft” martensite that is more resistant than standard martensitic ...Proposed AC Corrosion Models  AC Simulated Corrosion testing  Stainless steel pipe and coating  Cathodic protection  Experimental Setup  Preliminary

  12. Comparing Ns-DBD vs Ac-DBD plasma actuation mechanisms on a NACA 0012 airfoil

    NASA Astrophysics Data System (ADS)

    Singh, Ashish; Durasiewicz, Claudia; Little, Jesse

    2017-11-01

    A NACA 0012 airfoil is used to study ns-DBD and ac-DBD plasma actuators at a Reynolds number of 740,000 (U∞=40 m/s). Ns-DBD plasma actuators are hypothesized to work on the principle of joule heating whereas ac-DBD actuators add momentum to the flow. Short duration forcing at a time scale much smaller than the convective time based on model chord is employed to study the control mechanism and flow field response. 2-D PIV carried out over a convective time range of 0-10 is used to study the flow structure. The results show the breakup of shear layer vorticity at the point of actuation followed by reattachment to the suction side of the airfoil and finally stall again. These events are very similar between the two actuators and indicate a similar flow response to different perturbation types. The pulse energies are varied and the response shows little change. The results are compared to other transitory separation control studies using more conventional actuators. The detailed study of these two control mechanisms with the separated flow over an airfoil helps to shed light on the evolution of the flow control process. Additional results on a simplified model problem (low speed mixing layer) are included to provide context. Supported by U.S. Army Research Office (W911NF-14-1-0662).

  13. The effect of step height on the performance of three-dimensional ac electro-osmotic microfluidic pumps.

    PubMed

    Urbanski, John Paul; Levitan, Jeremy A; Burch, Damian N; Thorsen, Todd; Bazant, Martin Z

    2007-05-15

    Recent numerical and experimental studies have investigated the increase in efficiency of microfluidic ac electro-osmotic pumps by introducing nonplanar geometries with raised steps on the electrodes. In this study, we analyze the effect of the step height on ac electro-osmotic pump performance. AC electro-osmotic pumps with three-dimensional electroplated steps are fabricated on glass substrates and pumping velocities of low ionic strength electrolyte solutions are measured systematically using a custom microfluidic device. Numerical simulations predict an improvement in pump performance with increasing step height, at a given frequency and voltage, up to an optimal step height, which qualitatively matches the trend observed in experiment. For a broad range of step heights near the optimum, the observed flow is much faster than with existing planar pumps (at the same voltage and minimum feature size) and in the theoretically predicted direction of the "fluid conveyor belt" mechanism. For small step heights, the experiments also exhibit significant flow reversal at the optimal frequency, which cannot be explained by the theory, although the simulations predict weak flow reversal at higher frequencies due to incomplete charging. These results provide insight to an important parameter for the design of nonplanar electro-osmotic pumps and clues to improve the fundamental theory of ACEO.

  14. Lateral separation of colloids or cells by dielectrophoresis augmented by AC electroosmosis.

    PubMed

    Zhou, Hao; White, Lee R; Tilton, Robert D

    2005-05-01

    Colloidal particles and biological cells are patterned and separated laterally adjacent to a micropatterned electrode array by applying AC electric fields that are principally oriented normally to the electrode array. This is demonstrated for yeast cells, red blood cells, and colloidal polystyrene particles of different sizes and zeta-potentials. The separation mechanism is observed experimentally to depend on the applied field frequency and voltage. At high frequencies, particles position themselves in a manner that is consistent with dielectrophoresis, while at low frequencies, the positioning is explained in terms of a strong coupling between gravity, the vertical component of the dielectrophoretic force, and the Stokes drag on particles induced by AC electroosmotic flow. Compared to high frequency dielectrophoretic separations, the low frequency separations are faster and require lower applied voltages. Furthermore, the AC electroosmosis coupling with dielectrophoresis may enable cell separations that are not feasible based on dielectrophoresis alone.

  15. Clock Controller For Ac Self-Timing Analysis Of Logic System

    DOEpatents

    Lo, Tinchee; Flanagan, John D.

    2004-05-18

    A clock controller and clock generating method are provided for AC self-test timing analysis of a logic system. The controller includes latch circuitry which receives a DC input signal at a data input, and a pair of continuous out-of-phase clock signals at capture and launch clock inputs thereof. The latch circuitry outputs two overlapping pulses responsive to the DC input signal going high. The two overlapping pulses are provided to waveform shaper circuitry which produces therefrom two non-overlapping pulses at clock speed of the logic system to be tested. The two non-overlapping pulses are a single pair of clock pulses which facilitate AC self-test timing analysis of the logic system.

  16. High surface area bio-waste based carbon as a superior electrode for vanadium redox flow battery

    NASA Astrophysics Data System (ADS)

    Maharjan, Makhan; Bhattarai, Arjun; Ulaganathan, Mani; Wai, Nyunt; Oo, Moe Ohnmar; Wang, Jing-Yuan; Lim, Tuti Mariana

    2017-09-01

    Activated carbon (AC) with high surface area (1901 m2 g-1) is synthesized from low cost bio-waste orange (Citrus sinensis) peel for vanadium redox flow battery (VRB). The composition, structure and electrochemical properties of orange peel derived AC (OP-AC) are characterized by elemental analyzer, field emission-scanning electron microscopy, X-ray diffraction, Raman spectroscopy, X-ray photoelectron spectroscopy, cyclic voltammetry (CV), and electrochemical impedance spectroscopy. CV results show that OP-AC coated bipolar plate demonstrates improved electro-catalytic activity in both positive and negative side redox couples than the pristine bipolar plate electrode and this is ascribed to the high surface area of OP-AC which provides effective electrode area and better contact between the porous electrode and bipolar plate. Consequently, the performance of VRB in a static cell shows higher energy efficiency for OP-AC electrode than the pristine electrode at all current densities tested. The results suggest the OP-AC to be a promising electrode for VRB applications and can be incorporated into making conducting plastics electrode to lower the VRB cell stack weight and cost.

  17. Combined AC electroosmosis and dielectrophoresis for controlled rotation of microparticles

    PubMed Central

    Walid Rezanoor, Md.; Dutta, Prashanta

    2016-01-01

    Electrorotation is widely used for characterization of biological cells and materials using a rotating electric field. Generally, multiphase AC electric fields and quadrupolar electrode configuration are needed to create a rotating electric field for electrorotation. In this study, we demonstrate a simple method to rotate dielectrophoretically trapped microparticles using a stationary AC electric field. Coplanar interdigitated electrodes are used to create a linearly polarized nonuniform AC electric field. This nonuniform electric field is employed for dielectrophoretic trapping of microparticles as well as for generating electroosmotic flow in the vicinity of the electrodes resulting in rotation of microparticles in a microfluidic device. The rotation of barium titanate microparticles is observed in 2-propanol and methanol solvent at a frequency below 1 kHz. A particle rotation rate as high as 240 revolutions per minute is observed. It is demonstrated that precise manipulation (both rotation rate and equilibrium position) of the particles is possible by controlling the frequency of the applied electric field. At low frequency range, the equilibrium positions of the microparticles are observed between the electrode edge and electrode center. This method of particle manipulation is different from electrorotation as it uses induced AC electroosmosis instead of electric torque as in the case of electrorotation. Moreover, it has been shown that a microparticle can be rotated along its own axis without any translational motion. PMID:27014394

  18. Combined AC electroosmosis and dielectrophoresis for controlled rotation of microparticles.

    PubMed

    Walid Rezanoor, Md; Dutta, Prashanta

    2016-03-01

    Electrorotation is widely used for characterization of biological cells and materials using a rotating electric field. Generally, multiphase AC electric fields and quadrupolar electrode configuration are needed to create a rotating electric field for electrorotation. In this study, we demonstrate a simple method to rotate dielectrophoretically trapped microparticles using a stationary AC electric field. Coplanar interdigitated electrodes are used to create a linearly polarized nonuniform AC electric field. This nonuniform electric field is employed for dielectrophoretic trapping of microparticles as well as for generating electroosmotic flow in the vicinity of the electrodes resulting in rotation of microparticles in a microfluidic device. The rotation of barium titanate microparticles is observed in 2-propanol and methanol solvent at a frequency below 1 kHz. A particle rotation rate as high as 240 revolutions per minute is observed. It is demonstrated that precise manipulation (both rotation rate and equilibrium position) of the particles is possible by controlling the frequency of the applied electric field. At low frequency range, the equilibrium positions of the microparticles are observed between the electrode edge and electrode center. This method of particle manipulation is different from electrorotation as it uses induced AC electroosmosis instead of electric torque as in the case of electrorotation. Moreover, it has been shown that a microparticle can be rotated along its own axis without any translational motion.

  19. The Use of AC-DC-AC Methods in Assessing Corrosion Resistance Performance of Coating Systems for Magnesium Alloys

    NASA Astrophysics Data System (ADS)

    McCune, Robert C.; Upadhyay, Vinod; Wang, Yar-Ming; Battocchi, Dante

    The potential utility of AC-DC-AC electrochemical methods in comparative measures of corrosion-resisting coating system performance for magnesium alloys under consideration for the USAMP "Magnesium Front End Research and Development" project was previously shown in this forum [1]. Additional studies of this approach using statistically-designed experiments have been conducted with focus on alloy types, pretreatment, topcoat material and topcoat thickness as the variables. Additionally, sample coupons made for these designed experiments were also subjected to a typical automotive cyclic corrosion test cycle (SAE J2334) as well as ASTM B117 for comparison of relative performance. Results of these studies are presented along with advantages and limitations of the proposed methodology.

  20. Testing FlowTracker2 Performance and Wading Rod Flow Disturbance in Laboratory Tow Tanks

    NASA Astrophysics Data System (ADS)

    Fan, X.; Wagenaar, D.

    2016-12-01

    The FlowTracker2 was released in February 2016 by SonTek (Xylem) to be a more feature-rich and technologically advanced replacement to the Original FlowTracker ADV. These instruments are Acoustic Doppler Velocimeters (ADVs) used for taking high-precision wading discharge and velocity measurements. The accuracy of the FlowTracker2 probe was tested in tow tanks at three different facilities: the USGS Hydrologic Instrumentation Facility (HIF), the Swiss Federal Institute for Metrology (METAS), and at the SonTek Research and Development facility. Multiple mounting configurations were examined, including mounting the ADV probe directly to the tow carts, and incorporating the two most-used wading rods for the FlowTracker (round and hex). Tow speeds ranged from 5cm/s to 1.5m/s, and different tow tank seeding schemes and wait times were examined. In addition, the performance of the FlowTracker2 probe in low Signal-to-Noise Ratio (SNR) environments was compared to the Original FlowTracker ADV. Results confirmed that the FlowTracker2 probe itself performed well within the 1%+0.25cm/s accuracy specification advertised. Tows using the wading rods created a reduced measured velocity by 1.3% of the expected velocity due to flow disturbance, a result similar to the Original FlowTracker ADV despite the change in the FlowTracker2 probe design. Finally, due to improvements in its electronics, the FlowTracker2's performance in low SNR tests exceeded that of the Original FlowTracker ADV, showing less standard error in these conditions compared to its predecessor.

  1. Curved-flow, rolling-flow, and oscillatory pure-yawing wind-tunnel test methods for determination of dynamic stability derivatives

    NASA Technical Reports Server (NTRS)

    Chambers, J. R.; Grafton, S. B.; Lutze, F. H.

    1981-01-01

    Dynamic stability derivatives are evaluated on the basis of rolling-flow, curved-flow and snaking tests. Attention is given to the hardware associated with curved-flow, rolling-flow and oscillatory pure-yawing wind-tunnel tests. It is found that the snaking technique, when combined with linear- and forced-oscillation methods, yields an important method for evaluating beta derivatives for current configurations at high angles of attack. Since the rolling flow model is fixed during testing, forced oscillations may be imparted to the model, permitting the measurement of damping and cross-derivatives. These results, when coupled with basic rolling-flow or rotary-balance data, yield a highly accurate mathematical model for studies of incipient spin and spin entry.

  2. Improvement program for polycarbonate capacitors. [hermetically sealed, and ac wound

    NASA Technical Reports Server (NTRS)

    Bailey, R. R.; Waterman, K. D.

    1973-01-01

    Hermetically sealed, wound, AC, polycarbonate capacitors incorporating design improvements recommended in a previous study were designed and built. A 5000 hour, 400 Hz ac life test was conducted using 384 of these capacitors to verify the adequacy of the design improvements. The improvements incorporated in the capacitors designed for this program eliminated the major cause of failure found in the preceding work, termination failure. A failure cause not present in the previous test became significant in this test with capacitors built from one lot of polycarbonate film. The samples from this lot accounted for 25 percent of the total test complement. Analyses of failed samples showed that the film had an excessive solvent content. This solvent problem was found in 37 of the total 46 failures which occurred in this test. The other nine were random failures resulting from causes such as seal leaks, foreign particles, and possibly wrinkles.

  3. Dynamic ADMM for Real-Time Optimal Power Flow

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

    Dall-Anese, Emiliano; Zhang, Yijian; Hong, Mingyi

    This paper considers distribution networks featuring distributed energy resources (DERs), and develops a dynamic optimization method to maximize given operational objectives in real time while adhering to relevant network constraints. The design of the dynamic algorithm is based on suitable linearization of the AC power flow equations, and it leverages the so-called alternating direction method of multipliers (ADMM). The steps of the ADMM, however, are suitably modified to accommodate appropriate measurements from the distribution network and the DERs. With the aid of these measurements, the resultant algorithm can enforce given operational constraints in spite of inaccuracies in the representation ofmore » the AC power flows, and it avoids ubiquitous metering to gather the state of noncontrollable resources. Optimality and convergence of the proposed algorithm are established in terms of tracking of the solution of a convex surrogate of the AC optimal power flow problem.« less

  4. Development and Testing of the Europa Mission's Venturi Flow Meter

    NASA Technical Reports Server (NTRS)

    Diaz, C. E.; McKim, S. A.

    2017-01-01

    NASA's Marshall Space Flight Center (MSFC), in collaboration with NASA's Goddard Space Flight Center (GSFC), Fox Valve Development Corp. and Oxford Lasers, is developing a set of venturi flow meters for use on the Europa Mission's propulsion subsystem. The requirement for the venturi flow meters' throat diameters is approximately 0.040". An early risk reduction activity conducted by MSFC revealed that a venturi flow meter produced by FOX with a throat diameter near 0.040" had much higher pressure loss than venturi flow meters with larger throat diameters and venturis of similar throat diameter size but with no pressure taps (i.e. venturis with a throat length to diameter ratio of zero). In response, a series of venturi flow meters was fabricated and flow tested to gain insight into pressure recovery as it is affected by pressure port diameter, throat length and diffuser angle in an effort to improve the performance of a venturi flow meter. This presentation provides a summary of the venturi flow meter development activity including: a description of the test's objectives, a detailed description of each venturi configuration, a description of the manufacturing processes of the venturis, and observations from the test data. A summary of the current development activities will also be given, as well as the current development path forward. Ultimately, the knowledge gained through the fabrication and testing of these venturis provides guidance to design a flight venturi flow meters with pressure recoveries that is acceptable for the Europa flight application.

  5. Development of software to improve AC power quality on large spacecraft

    NASA Technical Reports Server (NTRS)

    Kraft, L. Alan

    1991-01-01

    To insure the reliability of a 20 kHz, AC power system on spacecraft, it is essential to analyze its behavior under many adverse operating conditions. Some of these conditions include overloads, short circuits, switching surges, and harmonic distortions. Harmonic distortions can cause malfunctions in equipment that the power system is supplying, and during extreme distortions such as voltage resonance, it can cause equipment and insulation failures due to the extreme peak voltages. HARMFLO, a power flow computer program, which was capable of analyzing harmonic conditions on three phase, balanced, 60 Hz, AC power systems, was modified to analyze single phase, 20 kHz, AC power systems. Since almost all of the equipment used on spacecraft power systems is electrically different from equipment used on terrestrial power systems, it was also necessary to develop mathematical models for the equipment to be used on the spacecraft. The results are that (1) the harmonic power now has a model of a single phase, voltage controlled, full wave rectifier; and (2) HARMFLO was ported to the SUN workstation platform.

  6. Effect of ac electric field on the dynamics of a vesicle under shear flow in the small deformation regime

    NASA Astrophysics Data System (ADS)

    Sinha, Kumari Priti; Thaokar, Rochish M.

    2018-03-01

    Vesicles or biological cells under simultaneous shear and electric field can be encountered in dielectrophoretic devices or designs used for continuous flow electrofusion or electroporation. In this work, the dynamics of a vesicle subjected to simultaneous shear and uniform alternating current (ac) electric field is investigated in the small deformation limit. The coupled equations for vesicle orientation and shape evolution are derived theoretically, and the resulting nonlinear equations are handled numerically to generate relevant phase diagrams that demonstrate the effect of electrical parameters on the different dynamical regimes such as tank treading (TT), vacillating breathing (VB) [called trembling (TR) in this work], and tumbling (TU). It is found that while the electric Mason number (Mn), which represents the relative strength of the electrical forces to the shear forces, promotes the TT regime, the response itself is found to be sensitive to the applied frequency as well as the conductivity ratio. While higher outer conductivity promotes orientation along the flow axis, orientation along the electric field is favored when the inner conductivity is higher. Similarly a switch of orientation from the direction of the electric field to the direction of flow is possible by a mere change of frequency when the outer conductivity is higher. Interestingly, in some cases, a coupling between electric field-induced deformation and shear can result in the system admitting an intermediate TU regime while attaining the TT regime at high Mn. The results could enable designing better dielectrophoretic devices wherein the residence time as well as the dynamical states of the vesicular suspension can be controlled as per the application.

  7. AC/RC Force Integration

    DTIC Science & Technology

    1991-05-01

    ib qeocie. Thki document may not be rdeaed for open publicado. untit hu been deared by die appropriate military seavice or a veunent agency. AC /RC...A N/A N/A 11. TITLE (Include Security Classification) AC /RC Force Structure Integraticn 12. PERSONAL AUTHOR(S) Russell A. Eggers 13a. TYPE OF REPORT... AC ) and Reserve Components (RC) Force Integration is critical in today’s Total Army. The Army of soldiers, Active and Reserve, exists to play a key

  8. [Expression of AC133 vs. CD34 in acute childhood leukemias].

    PubMed

    Ebener, U; Brinkmann, A; Zotova, V; Niegemann, E; Wehner, S

    2000-01-01

    AC133, a newly discovered antigen on human progenitor cells, demonstrating 5-transmembranous domains is expressed by 30-60% out of all CD34+ cells. Our aim therefore was to investigate the extent of human stem-/progenitor cells expressing AC133 antigen in umbilical cord blood, peripheral blood without or following an application of granulocyte-colony stimulating factor (rhG-CSF). The main task was the investigation of bone marrow aspirates derived from children suffering from newly diagnosed acute leukemias, as well as from patients with a relapse or during a complete remission. The determination of antigen expression was done by application of flow cytometry (FACScan analysis) and the usage of newly developed monoclonal antibodies (AC133/1 and AC133/2; Miltenyi Biotec GmbH) in combination with monoclonal antibody directed against CD34-antigens (HPCA-2; BD). Our studies till now show average percentages in umbilical cord blood derived from 43 newborns about 0.294 +/- 0.165% AC133+ vs. 0.327 +/- 0.156% CD34+ hematopoietic stem-/progenitor cells (HSPC). In peripheral blood from 11 healthy donors we verified up to 0.15% CD34+ as well as AC133+ HSPC's. The concentration of progenitor cells was found to be obviously higher in peripheral blood from children with various diseases (neuroblastoma, rhabdomyosarcoma, ALL/AML) and undergoing application with rhG-CSF in order to be prepared for PBSC-transplantation. In those cases we found up to 3.51% AC133+ cells as well as slightly higher values (3.94%) for CD34 antigens. Additionally we quantified 128 bone marrow (BM) samples for AC133+ and CD34+ cells. In 10 BM samples, derived from patients without any neoplasia, the CD34+ cells were about 0.03% and 1.49%, whereas AC133 values were up to 0.64%. Bone marrow aspirates from 53 children with acute leukemias at time of diagnosis (ALL: n = 41/AML: n = 12) have been immunophenotyped and leukemic blast cells have been proved for AC133- and CD34 antigen expression. 32/41 (78%) of

  9. Characterizing fiber-reinforced composite structures using AC-impedance spectroscopy (AC-IS)

    NASA Astrophysics Data System (ADS)

    Woo, Leta Y.

    Property enhancement in composites depends largely on the reinforcement. For fiber-reinforced composites, the distribution of fibers is crucial in determining the electrical and mechanical performance. Image analysis methods for characterization can be time-consuming and/or destructive. This work explores the capability of AC-impedance spectroscopy (AC-IS), an electrical measurement technique, to serve as a rapid, non-destructive tool for characterizing composite microstructure. The composite requirements include a filler that is electrically conducting or semi-conducting with higher conductivity than the matrix, and a high-impedance interface or coating between the filler and the matrix. To establish an AC-IS characterization method, cement-matrix composites with steel reinforcement were employed as both a technologically important and a model system to investigate how fibers affect the electrical response. Beginning with spherical particulates and then fibers, composites were examined using composite theory and an "intrinsic conductivity" approach. The intrinsic conductivity approach applies to composites with low volume fractions of fibers (i.e., in the dilute regime) and relates how the composite conductivity varies relative to the matrix as a function of volume fraction. A universal equivalent circuit model was created to understand the AC-IS response of composites based on the geometry and volume fraction of the filler. Deviation from predicted behavior was assessed using a developed f-function, which quantifies how fibers contribute to the overall electrical response of the composite. Using the f-function, an AC-IS method for investigating fiber dispersion was established to characterize alignment, settling/segregation, and aggregation. Alignment was investigated using measurements made in three directions. A point-probe technique characterized settling and/or large-scale inhomogeneous mixing in samples. Aggregation was quantified using a "dispersion factor

  10. A flight test of laminar flow control leading-edge systems

    NASA Technical Reports Server (NTRS)

    Fischer, M. C.; Wright, A. S., Jr.; Wagner, R. D.

    1983-01-01

    NASA's program for development of a laminar flow technology base for application to commercial transports has made significant progress since its inception in 1976. Current efforts are focused on development of practical reliable systems for the leading-edge region where the most difficult problems in applying laminar flow exist. Practical solutions to these problems will remove many concerns about the ultimate practicality of laminar flow. To address these issues, two contractors performed studies, conducted development tests, and designed and fabricated fully functional leading-edge test articles for installation on the NASA JetStar aircraft. Systems evaluation and performance testing will be conducted to thoroughly evaluate all system capabilities and characteristics. A simulated airline service flight test program will be performed to obtain the operational sensitivity, maintenance, and reliability data needed to establish that practical solutions exist for the difficult leading-edge area of a future commercial transport employing laminar flow control.

  11. Comparative performance evaluation of advanced AC and DC EV propulsion systems

    NASA Astrophysics Data System (ADS)

    MacDowall, R. D.; Crumley, R. L.

    Idaho National Engineering Laboratory (INEL) evaluates EV propulsion systems and components for the U.S. Department of Energy (DOE) Electric and Hybrid Vehicle (EHV) Program. In this study, experimental data were used to evaluate the relative performances of the benchmark Chrysler/GE ETV-1 DC and the Ford/GE First Generation Single-Shaft AC (ETX-I) propulsion systems. Tests were conducted on the INEL's chassis dynamometer using identical aerodynamic and rolling resistance road-load coefficients and vehicle test weights. The results allowed a direct comparison of selected efficiency and performance characteristics for the two propulsion system technologies. The ETX-I AC system exhibited slightly lower system efficiency during constant speed testing than the ETV-1 DC propulsion system.

  12. Absorption and Attenuation Coefficients Using the WET Labs ac-s in the Mid-Atlantic Bight: Field Measurements and Data Analysis

    NASA Technical Reports Server (NTRS)

    Ohi, Nobuaki; Makinen, Carla P.; Mitchell, Richard; Moisan, Tiffany A.

    2008-01-01

    Ocean color algorithms are based on the parameterization of apparent optical properties as a function of inherent optical properties. WET Labs underwater absorption and attenuation meters (ac-9 and ac-s) measure both the spectral beam attenuation [c (lambda)] and absorption coefficient [a (lambda)]. The ac-s reports in a continuous range of 390-750 nm with a band pass of 4 nm, totaling approximately 83 distinct wavelengths, while the ac-9 reports at 9 wavelengths. We performed the ac-s field measurements at nine stations in the Mid-Atlantic Bight from water calibrations to data analysis. Onboard the ship, the ac-s was calibrated daily using Milli Q-water. Corrections for the in situ temperature and salinity effects on optical properties of water were applied. Corrections for incomplete recovery of the scattered light in the ac-s absorption tube were performed. The fine scale of spectral and vertical distributions of c (lambda) and a (lambda) were described from the ac-s. The significant relationships between a (674) and that of spectrophotometric analysis and chlorophyll a concentration of discrete water samples were observed.

  13. Optoelectrofluidic enhanced immunoreaction based on optically-induced dynamic AC electroosmosis.

    PubMed

    Han, Dongsik; Park, Je-Kyun

    2016-04-07

    We report a novel optoelectrofluidic immunoreaction system based on electroosmotic flow for enhancing antibody-analyte binding efficiency on a surface-based sensing system. Two conventional indium tin oxide glass slides are assembled to provide a reaction chamber for a tiny volume of sample droplet (∼5 μL), in which the top layer is employed as an antibody-immobilized substrate and the bottom layer acts as a photoconductive layer of an optoelectrofluidic device. Under the application of an AC voltage, an illuminated light pattern on the photoconductive layer causes strong counter-rotating vortices to transport analytes from the bulk solution to the vicinity of the assay spot on the glass substrate. This configuration overcomes the slow immunoreaction problem of a diffusion-based sensing system, resulting in the enhancement of binding efficiency via an optoelectrofluidic method. Furthermore, we investigate the effect of optically-induced dynamic AC electroosmotic flow on optoelectrofluidic enhancement for surface-based immunoreaction with a mathematical simulation study and real experiments using immunoglobulin G (IgG) and anti-IgG. As a result, dynamic light patterns provided better immunoreaction efficiency than static light patterns due to effective mass transport of the target analyte, resulting in an achievement of 2.18-fold enhancement under a growing circular light pattern compared to the passive mode.

  14. Reproducibility of up-flow column percolation tests for contaminated soils

    PubMed Central

    Naka, Angelica; Sakanakura, Hirofumi; Kurosawa, Akihiko; Inui, Toru; Takeo, Miyuki; Inoba, Seiji; Watanabe, Yasutaka; Fujikawa, Takuro; Miura, Toshihiko; Miyaguchi, Shinji; Nakajou, Kunihide; Sumikura, Mitsuhiro; Ito, Kenichi; Tamoto, Shuichi; Tatsuhara, Takeshi; Chida, Tomoyuki; Hirata, Kei; Ohori, Ken; Someya, Masayuki; Katoh, Masahiko; Umino, Madoka; Negishi, Masanori; Ito, Keijiro; Kojima, Junichi; Ogawa, Shohei

    2017-01-01

    Up-flow column percolation tests are used at laboratory scale to assess the leaching behavior of hazardous substance from contaminated soils in a specific condition as a function of time. Monitoring the quality of these test results inter or within laboratory is crucial, especially if used for Environment-related legal policy or for routine testing purposes. We tested three different sandy loam type soils (Soils I, II and III) to determine the reproducibility (variability inter laboratory) of test results and to evaluate the difference in the test results within laboratory. Up-flow column percolation tests were performed following the procedure described in the ISO/TS 21268–3. This procedure consists of percolating solution (calcium chloride 1 mM) from bottom to top at a flow rate of 12 mL/h through softly compacted soil contained in a column of 5 cm diameter and 30 ± 5 cm height. Eluate samples were collected at liquid-to-solid ratio of 0.1, 0.2, 0.5, 1, 2, 5 and 10 L/kg and analyzed for quantification of the target elements (Cu, As, Se, Cl, Ca, F, Mg, DOC and B in this research). For Soil I, 17 institutions in Japan joined this validation test. The up-flow column experiments were conducted in duplicate, after 48 h of equilibration time and at a flow rate of 12 mL/h. Column percolation test results from Soils II and III were used to evaluate the difference in test results from the experiments conducted in duplicate in a single laboratory, after 16 h of equilibration time and at a flow rate of 36 mL/h. Overall results showed good reproducibility (expressed in terms of the coefficient of variation, CV, calculated by dividing the standard deviation by the mean), as the CV was lower than 30% in more than 90% of the test results associated with Soil I. Moreover, low variability (expressed in terms of difference between the two test results divided by the mean) was observed in the test results related to Soils II and III, with a variability lower than 30% in more

  15. Aqueous stress-corrosion cracking of high-toughness D6AC steel

    NASA Technical Reports Server (NTRS)

    Gilbreath, W. P.; Adamson, M. J.

    1976-01-01

    The crack growth behavior of D6AC steel as a function of stress intensity, stress and corrosion history, and test technique, under sustained load in filtered natural seawater, 3.3 per cent sodium chloride solution, and distilled water, was investigated. Reported investigations of D6AC were considered in terms of the present study with emphasis on thermal treatment, specimen configuration, fracture toughness, crack-growth rates, initiation period, and threshold. Both threshold and growth kinetics were found to be relatively insensitive to these test parameters. The apparent incubation period was dependent on technique, both detection sensitivity and precracking stress intensity level.

  16. Measurements of Induced-Charge Electroosmotic Flow Around a Metallic Rod

    NASA Astrophysics Data System (ADS)

    Beskok, Ali; Canpolat, Cetin

    2012-11-01

    A cylindrical gold-coated stainless steel rod was positioned at the center of a straight microchannel connecting two fluid reservoirs on either end. The microchannel was filled with 1 mM KCl containing 0.5 micron diameter carboxylate-modified spherical particles. Induced-charge electro-osmotic (ICEO) flow occurred around the metallic rod under a sinusoidal AC electric field applied using two platinum electrodes. The ICEO flows around the metallic rod were measured using micro particle image velocimetry (micro-PIV) technique as functions of the AC electric field strength and frequency. The present study provides experimental data about ICEO flow in the weakly nonlinear limit of thin double layers, in which, the charging dynamics of the double layer cannot be presented analytically. Flow around the rod is quadrupolar, driving liquid towards the rod along the electric field and forcing it away from the rod in the direction perpendicular to the imposed electric field. The measured ICEO flow velocity is proportional to the square of the electric field strength, and depends on the applied AC frequency.

  17. Using Caspar Creek flow records to test peak flow estimation methods applicable to crossing design

    Treesearch

    Peter H. Cafferata; Leslie M. Reid

    2017-01-01

    Long-term flow records from sub-watersheds in the Caspar Creek Experimental Watersheds were used to test the accuracy of four methods commonly used to estimate peak flows in small forested watersheds: the Rational Method, the updated USGS Magnitude and Frequency Method, flow transference methods, and the NRCS curve number method. Comparison of measured and calculated...

  18. Nuclear Lamin A/C Deficiency Induces Defects in Cell Mechanics, Polarization, and Migration

    PubMed Central

    Lee, Jerry S. H.; Hale, Christopher M.; Panorchan, Porntula; Khatau, Shyam B.; George, Jerry P.; Tseng, Yiider; Stewart, Colin L.; Hodzic, Didier; Wirtz, Denis

    2007-01-01

    Lamin A/C is a major constituent of the nuclear lamina, a thin filamentous protein layer that lies beneath the nuclear envelope. Here we show that lamin A/C deficiency in mouse embryonic fibroblasts (Lmna−/− MEFs) diminishes the ability of these cells to polarize at the edge of a wound and significantly reduces cell migration speed into the wound. Moreover, lamin A/C deficiency induces significant separation of the microtubule organizing center (MTOC) from the nuclear envelope. Investigations using ballistic intracellular nanorheology reveal that lamin A/C deficiency also dramatically affects the micromechanical properties of the cytoplasm. Both the elasticity (stretchiness) and the viscosity (propensity of a material to flow) of the cytoplasm in Lmna−/− MEFs are significantly reduced. Disassembly of either the actin filament or microtubule networks in Lmna+/+ MEFs results in decrease of cytoplasmic elasticity and viscosity down to levels found in Lmna−/− MEFs. Together these results show that both the mechanical properties of the cytoskeleton and cytoskeleton-based processes, including cell motility, coupled MTOC and nucleus dynamics, and cell polarization, depend critically on the integrity of the nuclear lamina, which suggest the existence of a functional mechanical connection between the nucleus and the cytoskeleton. These results also suggest that cell polarization during cell migration requires tight mechanical coupling between MTOC and nucleus, which is mediated by lamin A/C. PMID:17631533

  19. Gas and Oil Flow through Wellbore Flaws

    NASA Astrophysics Data System (ADS)

    Hatambeigi, M.; Anwar, I.; Reda Taha, M.; Bettin, G.; Chojnicki, K. N.; Stormont, J.

    2017-12-01

    We have measured gas and oil flow through laboratory samples that represent two important potential flow paths in wellbores associated with the Strategic Petroleum Reserve (SPR): cement-steel interfaces (microannuli) and cement fractures. Cement fractures were created by tensile splitting of cement cores. Samples to represent microannuli were created by placing thin steel sheets within split cement cores so flow is channeled along the cement-steel interface. The test sequence included alternating gas and oil flow measurements. The test fluids were nitrogen and silicone oil with properties similar to a typical crude oil stored in the SPR. After correcting for non-linear (inertial) flow when necessary, flows were interpreted as effective permeability and hydraulic aperture using the cubic law. For both samples with cement fractures and those with cement-steel interfaces, initial gas and oil permeabilities were comparable. Once saturated with oil, a displacement pressure had to be overcome to establish gas flow through a sample, and the subsequent gas permeability were reduced by more than 50% compared to its initial value. Keywords: wellbore integrity, leakage, fracture, microannulus, SPR. Sandia National Laboratories is a multi-mission laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of NTESS/Honeywell, for the U.S. Department of Energy's National Nuclear Security Administration under contract DE-AC04-94AL85000. SAND2017-8168 A

  20. The ACS statistical analyzer

    DOT National Transportation Integrated Search

    2010-03-01

    This document provides guidance for using the ACS Statistical Analyzer. It is an Excel-based template for users of estimates from the American Community Survey (ACS) to assess the precision of individual estimates and to compare pairs of estimates fo...

  1. The Peak Flow Working Group: test of portable peak flow meters by explosive decompression.

    PubMed

    Pedersen, O F; Miller, M R

    1997-02-01

    In 1991, 50 new Vitalograph peak flow meters and 27 previously used mini-Wright peak flow meters were tested at three peak flows by use of a calibrator applying explosive decompression. The mini-Wright peak flow meters were also compared with eight new meters. For both makes of meter there was an excellent within-meter and between-meter variation. The accuracy, however, was poor, with a maximal overestimation of true flows of 50 and 70 L.min-1 in the interval from 200 to 400 L.min-1 for the Vitalograph and mini-Wright meters, respectively. The deviation is explained by the physical characteristics of the variable orifice peak flow meters. They have been supplied with equidistant scales, which give non-linear readings.

  2. Testing of a Liquid Oxygen/Liquid Methane Reaction Control Thruster in a New Altitude Rocket Engine Test Facility

    NASA Technical Reports Server (NTRS)

    Meyer, Michael L.; Arrington, Lynn A.; Kleinhenz, Julie E.; Marshall, William M.

    2012-01-01

    A relocated rocket engine test facility, the Altitude Combustion Stand (ACS), was activated in 2009 at the NASA Glenn Research Center. This facility has the capability to test with a variety of propellants and up to a thrust level of 2000 lbf (8.9 kN) with precise measurement of propellant conditions, propellant flow rates, thrust and altitude conditions. These measurements enable accurate determination of a thruster and/or nozzle s altitude performance for both technology development and flight qualification purposes. In addition the facility was designed to enable efficient test operations to control costs for technology and advanced development projects. A liquid oxygen-liquid methane technology development test program was conducted in the ACS from the fall of 2009 to the fall of 2010. Three test phases were conducted investigating different operational modes and in addition, the project required the complexity of controlling propellant inlet temperatures over an extremely wide range. Despite the challenges of a unique propellant (liquid methane) and wide operating conditions, the facility performed well and delivered up to 24 hot fire tests in a single test day. The resulting data validated the feasibility of utilizing this propellant combination for future deep space applications.

  3. The relationship of normal body temperature, end-expired breath temperature, and BAC/BrAC ratio in 98 physically fit human test subjects.

    PubMed

    Cowan, J Mack; Burris, James M; Hughes, James R; Cunningham, Margaret P

    2010-06-01

    The relationship between normal body temperature, end-expired breath temperature, and blood alcohol concentration (BAC)/breath alcohol concentration (BrAC) ratio was studied in 98 subjects (84 men, 14 women). Subjects consumed alcohol sufficient to produce a BrAC of at least 0.06 g/210 L 45-75 min after drinking. Breath samples were analyzed using an Intoxilyzer 8000 specially equipped to measure breath temperature. Venous blood samples and body temperatures were then taken. The mean body temperature of the men (36.6 degrees C) was lower than the women (37.0 degrees C); however, their mean breath temperatures were virtually identical (men: 34.5 degrees C; women: 34.6 degrees C). The BAC exceeded the BrAC for every subject. BAC/BrAC ratios were calculated from the BAC and BrAC analytical results. There was no difference in the BAC/BrAC ratios for men (1:2379) and women (1:2385). The correlation between BAC and BrAC was high (r = 0.938, p < 0.0001), whereas the correlations between body temperature and end-expired breath temperature, body temperature and BAC/BrAC ratio, and breath temperature and BAC/BrAC ratio were much lower. Neither normal body temperature nor end-expired breath temperature was strongly associated with BAC/BrAC ratio.

  4. Dynamic ADMM for Real-Time Optimal Power Flow: Preprint

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

    Dall-Anese, Emiliano; Zhang, Yijian; Hong, Mingyi

    This paper considers distribution networks featuring distributed energy resources (DERs), and develops a dynamic optimization method to maximize given operational objectives in real time while adhering to relevant network constraints. The design of the dynamic algorithm is based on suitable linearizations of the AC power flow equations, and it leverages the so-called alternating direction method of multipliers (ADMM). The steps of the ADMM, however, are suitably modified to accommodate appropriate measurements from the distribution network and the DERs. With the aid of these measurements, the resultant algorithm can enforce given operational constraints in spite of inaccuracies in the representation ofmore » the AC power flows, and it avoids ubiquitous metering to gather the state of non-controllable resources. Optimality and convergence of the propose algorithm are established in terms of tracking of the solution of a convex surrogate of the AC optimal power flow problem.« less

  5. Testing and Performance Verification of a High Bypass Ratio Turbofan Rotor in an Internal Flow Component Test Facility

    NASA Technical Reports Server (NTRS)

    VanZante, Dale E.; Podboy, Gary G.; Miller, Christopher J.; Thorp, Scott A.

    2009-01-01

    A 1/5 scale model rotor representative of a current technology, high bypass ratio, turbofan engine was installed and tested in the W8 single-stage, high-speed, compressor test facility at NASA Glenn Research Center (GRC). The same fan rotor was tested previously in the GRC 9x15 Low Speed Wind Tunnel as a fan module consisting of the rotor and outlet guide vanes mounted in a flight-like nacelle. The W8 test verified that the aerodynamic performance and detailed flow field of the rotor as installed in W8 were representative of the wind tunnel fan module installation. Modifications to W8 were necessary to ensure that this internal flow facility would have a flow field at the test package that is representative of flow conditions in the wind tunnel installation. Inlet flow conditioning was designed and installed in W8 to lower the fan face turbulence intensity to less than 1.0 percent in order to better match the wind tunnel operating environment. Also, inlet bleed was added to thin the casing boundary layer to be more representative of a flight nacelle boundary layer. On the 100 percent speed operating line the fan pressure rise and mass flow rate agreed with the wind tunnel data to within 1 percent. Detailed hot film surveys of the inlet flow, inlet boundary layer and fan exit flow were compared to results from the wind tunnel. The effect of inlet casing boundary layer thickness on fan performance was quantified. Challenges and lessons learned from testing this high flow, low static pressure rise fan in an internal flow facility are discussed.

  6. F-16XL-2 Supersonic Laminar Flow Control Flight Test Experiment

    NASA Technical Reports Server (NTRS)

    Anders, Scott G.; Fischer, Michael C.

    1999-01-01

    The F-16XL-2 Supersonic Laminar Flow Control Flight Test Experiment was part of the NASA High-Speed Research Program. The goal of the experiment was to demonstrate extensive laminar flow, to validate computational fluid dynamics (CFD) codes and design methodology, and to establish laminar flow control design criteria. Topics include the flight test hardware and design, airplane modification, the pressure and suction distributions achieved, the laminar flow achieved, and the data analysis and code correlation.

  7. Stennis Space Center Conducts Water Flow Test On The B-2 Test Stand

    NASA Image and Video Library

    2018-05-04

    Stennis Space Center completed a water flow test of the refurbished B-2 Test Stand on May 4, 2018. This included both the deflector and the aspirator, individually and together. This test stand is being prepared for the testing of the Space Launch System's booster core, which will utilize four RS-25 rocket engines.

  8. The AC photovoltaic module is here!

    NASA Astrophysics Data System (ADS)

    Strong, Steven J.; Wohlgemuth, John H.; Wills, Robert H.

    1997-02-01

    This paper describes the design, development, and performance results of a large-area photovoltaic module whose electrical output is ac power suitable for direct connection to the utility grid. The large-area ac PV module features a dedicated, integrally mounted, high-efficiency dc-to-ac power inverter with a nominal output of 250 watts (STC) at 120 Vac, 60 H, that is fully compatible with utility power. The module's output is connected directly to the building's conventional ac distribution system without need for any dc wiring, string combiners, dc ground-fault protection or additional power-conditioning equipment. With its advantages, the ac photovoltaic module promises to become a universal building block for use in all utility-interactive PV systems. This paper discusses AC Module design aspects and utility interface issues (including islanding).

  9. Influence of thermal aging on AC leakage current in XLPE insulation

    NASA Astrophysics Data System (ADS)

    Geng, Pulong; Song, Jiancheng; Tian, Muqin; Lei, Zhipeng; Du, Yakun

    2018-02-01

    Cross-linked polyethylene (XLPE) has been widely used as cable insulation material because of its excellent dielectric properties, thermal stability and solvent resistance. To understand the influence of thermal aging on AC leakage current in XLPE insulation, all XLPE specimens were aged in oven in temperature range from 120 °C to 150 °C, and a series of tests were conducted on these XLPE specimens in different aging stages to measure the characteristic parameters, such as complex permittivity, leakage current and complex dielectric modulus. In the experiments, the effects of thermal aging, temperature and frequency on the AC leakage current in XLPE insulation were studied by analyzing complex dielectric constant and dielectric relaxation modulus spectrum, the change of relaxation peak and activation energy. It has been found that the active part of leakage current increases sharply with the increase of aging degree, and the test temperature and frequency have an influence on AC leakage current but the influence of test temperature is mainly reflected in the low frequency region. In addition, it has been shown by the experiments that the reactive part of leakage current exhibits a strong frequency dependent characteristic in the testing frequency range from 10-2 Hz to 105 Hz, but the influence of test temperature and thermal aging on it is relatively small.

  10. Universal Verification Methodology Based Register Test Automation Flow.

    PubMed

    Woo, Jae Hun; Cho, Yong Kwan; Park, Sun Kyu

    2016-05-01

    In today's SoC design, the number of registers has been increased along with complexity of hardware blocks. Register validation is a time-consuming and error-pron task. Therefore, we need an efficient way to perform verification with less effort in shorter time. In this work, we suggest register test automation flow based UVM (Universal Verification Methodology). UVM provides a standard methodology, called a register model, to facilitate stimulus generation and functional checking of registers. However, it is not easy for designers to create register models for their functional blocks or integrate models in test-bench environment because it requires knowledge of SystemVerilog and UVM libraries. For the creation of register models, many commercial tools support a register model generation from register specification described in IP-XACT, but it is time-consuming to describe register specification in IP-XACT format. For easy creation of register model, we propose spreadsheet-based register template which is translated to IP-XACT description, from which register models can be easily generated using commercial tools. On the other hand, we also automate all the steps involved integrating test-bench and generating test-cases, so that designers may use register model without detailed knowledge of UVM or SystemVerilog. This automation flow involves generating and connecting test-bench components (e.g., driver, checker, bus adaptor, etc.) and writing test sequence for each type of register test-case. With the proposed flow, designers can save considerable amount of time to verify functionality of registers.

  11. Fibrillar disruption by AC electric field induced oscillation: A case study with human serum albumin.

    PubMed

    Sen, Shubhatam; Chakraborty, Monojit; Goley, Snigdha; Dasgupta, Swagata; DasGupta, Sunando

    2017-07-01

    The effect of oscillation induced by a frequency-dependent alternating current (AC) electric field to dissociate preformed amyloid fibrils has been investigated. An electrowetting-on-dielectric type setup has been used to apply the AC field of varying frequencies on preformed fibrils of human serum albumin (HSA). The disintegration potency has been monitored by a combination of spectroscopic and microscopic techniques. The experimental results suggest that the frequency of the applied AC field plays a crucial role in the disruption of preformed HSA fibrils. The extent of stress generated inside the droplet due to the application of the AC field at different frequencies has been monitored as a function of the input frequency of the applied AC voltage. This has been accomplished by assessing the morphology deformation of the oscillating HSA fibril droplets. The shape deformation of the oscillating droplets is characterized using image analysis by measuring the dynamic changes in the shape dependent parameters such as contact angle and droplet footprint radius and the amplitude. It is suggested that the cumulative effects of the stress generated inside the HSA fibril droplets due to the shape deformation induced hydrodynamic flows and the torque induced by the intrinsic electric dipoles of protein due to their continuous periodic realignment in presence of the AC electric field results in the destruction of the fibrillar species. Copyright © 2017. Published by Elsevier B.V.

  12. Flow Perturbation Mediates Neutrophil Recruitment and Potentiates Endothelial Injury via TLR2 in Mice – Implications for Superficial Erosion

    PubMed Central

    Franck, Grégory; Mawson, Thomas; Sausen, Grasiele; Salinas, Manuel; Masson, Gustavo Santos; Cole, Andrew; Beltrami-Moreira, Marina; Chatzizisis, Yiannis; Quillard, Thibault; Tesmenitsky, Yevgenia; Shvartz, Eugenia; Sukhova, Galina K.; Swirski, Filip K.; Nahrendorf, Matthias; Aikawa, Elena; Croce, Kevin J.; Libby, Peter

    2017-01-01

    Rationale Superficial erosion currently causes up to a third of acute coronary syndromes (ACS), yet we lack understanding of its mechanisms. Thrombi due to superficial intimal erosion characteristically complicate matrix-rich atheromata in regions of flow perturbation. Objective This study tested in vivo the involvement of disturbed flow, and of neutrophils, hyaluronan, and TLR2 ligation in superficial intimal injury, a process implicated in superficial erosion. Methods and Results : In mouse carotid arteries with established intimal lesions tailored to resemble the substrate of human eroded plaques, acute flow perturbation promoted downstream endothelial cell (EC) activation, neutrophil accumulation, EC death and desquamation, and mural thrombosis. Neutrophil loss-of-function limited these findings. TLR2 agonism activated luminal ECs, and deficiency of this innate immune receptor decreased intimal neutrophil adherence in regions of local flow disturbance, reducing EC injury and local thrombosis (p<0.05). Conclusions These results implicate flow disturbance, neutrophils, and TLR2 signaling as mechanisms that contribute to superficial erosion, a cause of ACS of likely growing importance in the statin era. PMID:28428204

  13. Cosmic shear analysis of archival HST/ACS data. I. Comparison of early ACS pure parallel data to the HST/GEMS survey

    NASA Astrophysics Data System (ADS)

    Schrabback, T.; Erben, T.; Simon, P.; Miralles, J.-M.; Schneider, P.; Heymans, C.; Eifler, T.; Fosbury, R. A. E.; Freudling, W.; Hetterscheidt, M.; Hildebrandt, H.; Pirzkal, N.

    2007-06-01

    Context: This is the first paper of a series describing our measurement of weak lensing by large-scale structure, also termed “cosmic shear”, using archival observations from the Advanced Camera for Surveys (ACS) on board the Hubble Space Telescope (HST). Aims: In this work we present results from a pilot study testing the capabilities of the ACS for cosmic shear measurements with early parallel observations and presenting a re-analysis of HST/ACS data from the GEMS survey and the GOODS observations of the Chandra Deep Field South (CDFS). Methods: We describe the data reduction and, in particular, a new correction scheme for the time-dependent ACS point-spread-function (PSF) based on observations of stellar fields. This is currently the only technique which takes the full time variation of the PSF between individual ACS exposures into account. We estimate that our PSF correction scheme reduces the systematic contribution to the shear correlation functions due to PSF distortions to <2 × 10-6 for galaxy fields containing at least 10 stars, which corresponds to ⪉5% of the cosmological signal expected on scales of a single ACS field. Results: We perform a number of diagnostic tests indicating that the remaining level of systematics is consistent with zero for the GEMS and GOODS data confirming the success of our PSF correction scheme. For the parallel data we detect a low level of remaining systematics which we interpret to be caused by a lack of sufficient dithering of the data. Combining the shear estimate of the GEMS and GOODS observations using 96 galaxies arcmin-2 with the photometric redshift catalogue of the GOODS-MUSIC sample, we determine a local single field estimate for the mass power spectrum normalisation σ8, CDFS=0.52+0.11-0.15 (stat) ± 0.07(sys) (68% confidence assuming Gaussian cosmic variance) at a fixed matter density Ω_m=0.3 for a ΛCDM cosmology marginalising over the uncertainty of the Hubble parameter and the redshift distribution. We

  14. Monitoring Fluid Flow in Fractured Carbonate Rocks Using Seismic Measurements

    NASA Astrophysics Data System (ADS)

    Li, W.; Pyrak-Nolte, L. J.

    2008-12-01

    The physical properties of carbonate rock are strongly influenced by the rock fabric which depends on the depositional environment, diagenetic and tectonic processes. The most common form of heterogeneity is layering caused by a variation in porosity among layers and within layers. The variation in porosity among layers leads to anisotropic behavior in the hydraulic, mechanical and seismic properties of carbonate rocks. We present the results of a laboratory study to examine the effect of fabric-controlled layering on fluid flow and seismic wave propagation through intact and fractured carbonate rock. Experiments were performed on cubic samples of Austin Chalk Cordova Cream. Samples AC1, AC5 and AC6 are cubic samples that measure 100 mm on edge. The samples were sealed and contained three inlet and three outlet ports for fluid invasion experiments. Two orthogonal seismic arrays were used to record both compressional and shear wave transmission through intact and fractured samples. The arrays used piezoelectric contact transducers with a central frequency 1.0 MHz. Between the two arrays, sixteen sources and sixteen receivers were used. Seismic measurements were made on the samples as a function of stress and during fluid saturation. The location of the invading fluid front as a function of time was monitored by using the peak-to-peak amplitude of the transmitted signals. The front was assumed to be between a source-receiver pair when the signal amplitude decreased by 50% over the initial value. The hydraulic gradient was parallel and perpendicular to the layers for AC5 and AC6, respectively. Sample AC1 was fractured and flow ports were established on the edges of the fracture plane. The weakly directed fabric controlled the rate at which fluid flowed through the samples. From the seismic data on AC6, the fluid first spread vertically along a layer before flowing across the layers. For AC6, it took the fluid two and half hours to flow between the inlet and the outlet

  15. ac Modeling and impedance spectrum tests of the superconducting magnetic field coils for the Wendelstein 7-X fusion experiment.

    PubMed

    Ehmler, Hartmut; Köppen, Matthias

    2007-10-01

    The impedance spectrum test was employed for detection of short circuits within Wendelstein 7-X (W7-X) superconducting magnetic field coils. This test is based on measuring the complex impedance over several decades of frequency. The results are compared to predictions of appropriate electrical equivalent circuits of coils in different production states or during cold test. When the equivalent circuit is not too complicated the impedance can be represented by an analytic function. A more detailed analysis is performed with a network simulation code. The overall agreement of measured and calculated or simulated spectra is good. Two types of short circuits which appeared are presented and analyzed. The detection limit of the method is discussed. It is concluded that combined high-voltage ac and low-voltage impedance spectrum tests are ideal means to rule out short circuits in the W7-X coils.

  16. Slow-onset and fast-onset symptom presentations in acute coronary syndrome (ACS): new perspectives on prehospital delay in patients with ACS.

    PubMed

    O'Donnell, Sharon; McKee, Gabrielle; Mooney, Mary; O'Brien, Frances; Moser, Debra K

    2014-04-01

    Patient decision delay is the main reason why many patients fail to receive timely medical intervention for symptoms of acute coronary syndrome (ACS). This study examines the validity of slow-onset and fast-onset ACS presentations and their influence on ACS prehospital delay times. A fast-onset ACS presentation is characterized by sudden, continuous, and severe chest pain, and slow-onset ACS pertains to all other ACS presentations. Baseline data pertaining to medical profiles, prehospital delay times, and ACS symptoms were recorded for all ACS patients who participated in a large multisite randomized control trial (RCT) in Dublin, Ireland. Patients were interviewed 2-4 days after their ACS event, and data were gathered using the ACS Response to Symptom Index. Only baseline data from the RCT, N = 893 patients, were analyzed. A total of 65% (n = 577) of patients experienced slow-onset ACS presentation, whereas 35% (n = 316) experienced fast-onset ACS. Patients who experienced slow-onset ACS were significantly more likely to have longer prehospital delays than patients with fast-onset ACS (3.5 h vs. 2.0 h, respectively, t = -5.63, df 890, p < 0.001). A multivariate analysis of delay revealed that, in the presence of other known delay factors, the only independent predictors of delay were slow-onset and fast-onset ACS (β = -.096, p < 0.002) and other factors associated with patient behavior. Slow-onset ACS and fast-onset ACS presentations are associated with distinct behavioral patterns that significantly influence prehospital time frames. As such, slow-onset ACS and fast-onset ACS are legitimate ACS presentation phenomena that should be seriously considered when examining the factors associated with prehospital delay. Copyright © 2014 Elsevier Inc. All rights reserved.

  17. Low AC Loss YBCO Coated Conductor Geometry by Direct Inkjet Printing

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

    Rupich, Martin, Dr.; Duckworth, Robert, Dr.

    The second generation (2G) high temperature superconductors (HTS) wire offers potential benefits for many electric power applications, including ones requiring filamentized conductors with low ac loss, such as transformers and fault current limiters. However, the use of 2G wire in these applications requires the development of both novel multi-filamentary conductor designs with lower ac losses and the development of advanced manufacturing technologies that enable the low-cost manufacturing of these filamentized architectures. This Phase I SBIR project focused on testing inkjet printing as a potential low-cost, roll-to-roll manufacturing technique to fabricate potential low ac loss filamentized architectures directly on the 2Gmore » template strips.« less

  18. Parameterization of the Voice Source by Combining Spectral Decay and Amplitude Features of the Glottal Flow.

    ERIC Educational Resources Information Center

    Alku, Paavo; Vilkman, Erkki; Laukkanen, Anne-Maria

    1998-01-01

    A new method is presented for the parameterization of glottal volume velocity waveforms that have been estimated by inverse filtering acoustic speech pressure signals. The new technique combines two features of voice production: the AC value and the spectral decay of the glottal flow. Testing found the new parameter correlates strongly with the…

  19. Transient AC voltage related phenomena for HVDC schemes connected to weak AC systems

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

    Pilotto, L.A.S.; Szechtman, M.; Hammad, A.E.

    1992-07-01

    In this paper a didactic explanation of voltage stability associated phenomena at HVDC terminals is presented. Conditions leading to ac voltage collapse problems are identified. A mechanism that excites control-induced voltage oscillations is shown. The voltage stability factor is used for obtaining the maximum power limits of ac/dc systems operating with different control strategies. Correlation to Pd {times} Id curves is given. Solutions for eliminating the risks of voltage collapse and for avoiding control-induced oscillations are discussed. The results are supported by detailed digital simulations of a weak ac/dc system using EMTP.

  20. Improved Tribological Performance of Amorphous Carbon (a-C) Coating by ZrO₂ Nanoparticles.

    PubMed

    Tang, Jinzhu; Ding, Qi; Zhang, Songwei; Wu, Guizhi; Hu, Litian

    2016-09-22

    Nanomaterials, such as Graphene, h-BN nanoparticles and MoS₂ nanotubes, have shown their ability in improving the tribological performance of amorphous carbon (a-C) coatings. In the current study, the effectiveness of ZrO₂ nanoparticles (ZrO₂-NPs) in lubricating the self-mated nonhydrogenated a-C contacts was investigated in boundary lubrication regime. The results showed that 13% less friction and 50% less wear compared to the base oil were achieved by employing ZrO₂-NPs in the base oil in self-mated a-C contacts. Via analyzing the ZrO₂-NPs and the worn a-C surface after tests, it was found that the improved lubrication by ZrO₂-NPs was based on "polishing effects", which is a new phenomenon observed between a-C and nanoparticles. Under the "polishing effect", micro-plateaus with extremely smooth surface and uniform height were produced on the analyzed a-C surface. The resulting topography of the a-C coating is suitable for ZrO₂-NPs to act as nano-bearings between rubbing surfaces. Especially, the ZrO₂-NPs exhibited excellent mechanical and chemical stability, even under the severe service condition, suggesting that the combination of nonhydrogenated a-C coating with ZrO₂-NPs is an effective, long lasting and environment-friendly lubrication solution.

  1. Characteristics Air Flow in Room Chamber Test Refrigerator Household Energy Consumption with Inlet Flow Variation

    NASA Astrophysics Data System (ADS)

    Susanto, Edy; Idrus Alhamid, M.; Nasruddin; Budihardjo

    2018-03-01

    Room Chamber is the most important in making a good Testing Laboratory. In this study, the 2-D modeling conducted to assess the effect placed the inlet on designing a test chamber room energy consumption of household refrigerators. Where the geometry room chamber is rectangular and approaching the enclosure conditions. Inlet varied over the side parallel to the outlet and compared to the inlet where the bottom is made. The purpose of this study was to determine and define the characteristics of the airflow in the room chamber using CFD simulation. CFD method is used to obtain flow characteristics in detail, in the form of vector flow velocity and temperature distribution inside the chamber room. The result found that the position of the inlet parallel to the outlet causes air flow cannot move freely to the side of the floor, even flow of air moves up toward the outlet. While by making the inlet is below, the air can move freely from the bottom up to the side of the chamber room wall as well as to help uniform flow.

  2. AC loss in YBCO coated conductors at high dB/dt measured using a spinning magnet calorimeter (stator testbed environment)

    NASA Astrophysics Data System (ADS)

    Murphy, J. P.; Gheorghiu, N. N.; Bullard, T.; Haugan, T.; Sumption, M. D.; Majoros, M.; Collings, E. W.

    2017-09-01

    A new facility for the measurement of AC loss in superconductors at high dB/dt has been developed. The test device has a spinning rotor consisting of permanent magnets arranged in a Halbach array; the sample, positioned outside of this, is exposed to a time varying AC field with a peak radial field of 0.566 T. At a rotor speed of 3600 RPM the frequency of the AC field is 240 Hz, the radial dB/dt is 543 T/s and the tangential dB/dt is 249 T/s. Loss is measured using nitrogen boiloff from a double wall calorimeter feeding a gas flow meter. The system is calibrated using power from a known resistor. YBCO tape losses were measured in the new device and compared to the results from a solenoidal magnet AC loss system measurement of the same samples (in this latter case measurements were limited to a field of amplitude 0.1 T and a dB/dt of 100 T/s). Solenoidal magnet system AC loss measurements taken on a YBCO sample agreed with the Brandt loss expression associated with a 0-0.1 T Ic of 128 A. Subsequently, losses for two more YBCO tapes nominally identical to the first were individually measured in this spinning magnet calorimeter (SMC) machine with a Bmax of 0.566 T and dB/dt of up to 272 T/s. The losses, compared to a simplified version of the Brandt expression, were consistent with the average Ic expected for the tape in the 0-0.5 T range at 77 K. The eddy current contribution was consistent with a 77 K residual resistance ratio, RR, of 4.0. The SMC results for these samples agreed to within 5%. Good agreement was also obtained between the results of the SMC AC loss measurement and the solenoidal magnet AC loss measurement on the same samples.

  3. Electrohydrodynamic Flows in Electrochemical Systems

    NASA Technical Reports Server (NTRS)

    Saville, D. A.

    2005-01-01

    Recent studies have established a new class of assembly processes with colloidal suspensions. Particles are driven together to form large crystalline structures in both dc and ac fields. The current work centers on this new class of flows in ac fields. In the research carried out under the current award, it was established that: (i) Small colloidal particles crystallize near an electrode due to electrohydrodynamic flows induced by an sinusoidally varying applied potential. (ii) These flows originate due to disturbances in the electrode polarization layer arising from the presence of the particles. Inasmuch as the charge and the field strength both scale on the applied field, the flows are proportional to the square of the applied voltage. (iii) Suspensions of two different sorts of particles can be crystallized and will form well-ordered binary crystals. (iv) At high frequencies the EHD flows die out. Thus, with a homogeneous system the particles become widely spaced due to dipolar repulsion. With a binary suspension, however, the particles may become attractive due to dipolar attraction arising from differences in electrokinetic dipoles. Consequently binary crystals form at both high and low frequencies.

  4. Microfabricated AC impedance sensor

    DOEpatents

    Krulevitch, Peter; Ackler, Harold D.; Becker, Frederick; Boser, Bernhard E.; Eldredge, Adam B.; Fuller, Christopher K.; Gascoyne, Peter R. C.; Hamilton, Julie K.; Swierkowski, Stefan P.; Wang, Xiao-Bo

    2002-01-01

    A microfabricated instrument for detecting and identifying cells and other particles based on alternating current (AC) impedance measurements. The microfabricated AC impedance sensor includes two critical elements: 1) a microfluidic chip, preferably of glass substrates, having at least one microchannel therein and with electrodes patterned on both substrates, and 2) electrical circuits that connect to the electrodes on the microfluidic chip and detect signals associated with particles traveling down the microchannels. These circuits enable multiple AC impedance measurements of individual particles at high throughput rates with sufficient resolution to identify different particle and cell types as appropriate for environmental detection and clinical diagnostic applications.

  5. Accelerated stress testing of amorphous silicon solar cells

    NASA Technical Reports Server (NTRS)

    Stoddard, W. G.; Davis, C. W.; Lathrop, J. W.

    1985-01-01

    A technique for performing accelerated stress tests of large-area thin a-Si solar cells is presented. A computer-controlled short-interval test system employing low-cost ac-powered ELH illumination and a simulated a-Si reference cell (seven individually bandpass-filtered zero-biased crystalline PIN photodiodes) calibrated to the response of an a-Si control cell is described and illustrated with flow diagrams, drawings, and graphs. Preliminary results indicate that while most tests of a program developed for c-Si cells are applicable to a-Si cells, spurious degradation may appear in a-Si cells tested at temperatures above 130 C.

  6. Diagnostics of AC excited Atmospheric Pressure Plasma Jet with He for Biomedical Applications

    NASA Astrophysics Data System (ADS)

    Hori, Masaru; Takeda, Keigo; Kumakura, Takumi; Ishikawa, Kenji; Tanaka, Hiromasa; Kondo, Hiroki; Sekine, Makoto; Nakai, Yoshihiro

    2014-10-01

    Atmospheric pressure plasma jets (APPJ) are frequently used for biomedical applications. Reactive species generated by the APPJ play important roles for treatments of biomedical samples. Therefore, high density APPJ sources are required to realize the high performance. Our group has developed AC excited Ar APPJ with electron density as high as 1015 cm-3, and realized the selective killing of cancer cells and the inactivate spores of Penicillium digitatum. Recently, a new spot-size AC excited APPJ with He gas have been developed. In this study, the He APPJ was characterized by using spectroscopy. The plasma was discharged at a He flow rate of 5 slm and a discharge voltage of AC 9 kV. Gas temperature and electron density of the APPJ were measured by optical emission spectroscopy. From theoretical fitting of 2nd positive system of N2 emission (380.4 nm) and Stark broadening of Balmer β line of H atom (486.1 nm), the gas temperature and the electron density was estimated to be 299 K and 3.4. × 1015 cm-3. The AC excited He APPJ has a potential to realize high density with room temperature and become a very powerful tool for biomedical applications.

  7. Flow Pattern Phenomena in Two-Phase Flow in Microchannels

    NASA Astrophysics Data System (ADS)

    Keska, Jerry K.; Simon, William E.

    2004-02-01

    Space transportation systems require high-performance thermal protection and fluid management techniques for systems ranging from cryogenic fluid management devices to primary structures and propulsion systems exposed to extremely high temperatures, as well as for other space systems such as cooling or environment control for advanced space suits and integrated circuits. Although considerable developmental effort is being expended to bring potentially applicable technologies to a readiness level for practical use, new and innovative methods are still needed. One such method is the concept of Advanced Micro Cooling Modules (AMCMs), which are essentially compact two-phase heat exchangers constructed of microchannels and designed to remove large amounts of heat rapidly from critical systems by incorporating phase transition. The development of AMCMs requires fundamental technological advancement in many areas, including: (1) development of measurement methods/systems for flow-pattern measurement/identification for two-phase mixtures in microchannels; (2) development of a phenomenological model for two-phase flow which includes the quantitative measure of flow patterns; and (3) database development for multiphase heat transfer/fluid dynamics flows in microchannels. This paper focuses on the results of experimental research in the phenomena of two-phase flow in microchannels. The work encompasses both an experimental and an analytical approach to incorporating flow patterns for air-water mixtures flowing in a microchannel, which are necessary tools for the optimal design of AMCMs. Specifically, the following topics are addressed: (1) design and construction of a sensitive test system for two-phase flow in microchannels, one which measures ac and dc components of in-situ physical mixture parameters including spatial concentration using concomitant methods; (2) data acquisition and analysis in the amplitude, time, and frequency domains; and (3) analysis of results

  8. High voltage AC/AC electrochemical capacitor operating at low temperature in salt aqueous electrolyte

    NASA Astrophysics Data System (ADS)

    Abbas, Qamar; Béguin, François

    2016-06-01

    We demonstrate that an activated carbon (AC)-based electrochemical capacitor implementing aqueous lithium sulfate electrolyte in 7:3 vol:vol water/methanol mixture can operate down to -40 °C with good electrochemical performance. Three-electrode cell investigations show that the faradaic contributions related with hydrogen chemisorption in the negative AC electrode are thermodynamically unfavored at -40 °C, enabling the system to work as a typical electrical double-layer (EDL) capacitor. After prolonged floating of the AC/AC capacitor at 1.6 V and -40°C, the capacitance, equivalent series resistance and efficiency remain constant, demonstrating the absence of ageing related with side redox reactions at this temperature. Interestingly, when temperature is increased back to 24 °C, the redox behavior due to hydrogen storage reappears and the system behaves as a freshly prepared one.

  9. Pre-test CFD Calculations for a Bypass Flow Standard Problem

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

    Rich Johnson

    The bypass flow in a prismatic high temperature gas-cooled reactor (HTGR) is the flow that occurs between adjacent graphite blocks. Gaps exist between blocks due to variances in their manufacture and installation and because of the expansion and shrinkage of the blocks from heating and irradiation. Although the temperature of fuel compacts and graphite is sensitive to the presence of bypass flow, there is great uncertainty in the level and effects of the bypass flow. The Next Generation Nuclear Plant (NGNP) program at the Idaho National Laboratory has undertaken to produce experimental data of isothermal bypass flow between three adjacentmore » graphite blocks. These data are intended to provide validation for computational fluid dynamic (CFD) analyses of the bypass flow. Such validation data sets are called Standard Problems in the nuclear safety analysis field. Details of the experimental apparatus as well as several pre-test calculations of the bypass flow are provided. Pre-test calculations are useful in examining the nature of the flow and to see if there are any problems associated with the flow and its measurement. The apparatus is designed to be able to provide three different gap widths in the vertical direction (the direction of the normal coolant flow) and two gap widths in the horizontal direction. It is expected that the vertical bypass flow will range from laminar to transitional to turbulent flow for the different gap widths that will be available.« less

  10. 7 CFR 28.603 - Procedures for air flow tests of micronaire reading.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... of the United States for Fiber Fineness and Maturity § 28.603 Procedures for air flow tests of... 7 Agriculture 2 2010-01-01 2010-01-01 false Procedures for air flow tests of micronaire reading...) Air flow instrument complete with accessories to measure the fineness and maturity, in combination, of...

  11. Function analysis of Ac-PCNA and Sf-PCNA during the Autographa californica multiple nucleopolyhedrovirus infection process.

    PubMed

    Fu, Yuejun; Wang, Ruisheng; Liang, Aihua

    2018-06-01

    The baculovirus Autographa californica multiple nucleopolyhedrovirus (AcMNPV) possesses a gene, ac-pcna or ac49, which encodes a protein with similarity to proliferating cell nuclear antigen (PCNA). Homologs of this gene code for DNA polymerase processivity factors and are essential in the DNA replication systems. But the function of ac-pcna still remains unclear. To define the function of Ac-pcna in AcMNPV and Sf-pcna in host Sf9 cells, Bac-to-Bac baculovirus expression system was used to generate two recombinant baculoviruses: AcMNPV-Ac-pcna-EGFP and AcMNPV-Sf-pcna-EGFP. Results indicated that AcMNPV-mediated overexpression of Ac-PCNA and Sf-PCNA could stimulate replication of AcMNPV genome in the host Sf9 cells. Meanwhile, either AcMNPV-Ac-pcna-EGFP or AcMNPV-Sf-pcna-EGFP had a significant stimulating effect on Sf9 genome replication during infection. We also found that Ac-PCNA and Sf-PCNA could promote the production of budded virus. Ac-PCNA could improve the transcription level of ie2 gene dramatically and further improved the transcription of late gene, for example 38 K and vp39, at 12 h p.i.. Moreover, insecticidal potency test showed that the larvae of Beet armyworm in the AcMNPV-Ac-pcna-EGFP and AcMNPV-Sf-pcna-EGFP groups had a higher mortality rate (83.33 and 91.67%), a lower pupation rate (16.67 and 8.33%), and a lower emergence rate (6.67 and 3.33%), compared with those in AcMNPV-EGFP group. The function of Ac-PCNA and Sf-PCNA was confirmed in this study, which provided the theoretical foundation for using and modifying AcMNPV.

  12. Measuring Gravitational Flexion in ACS Clusters

    NASA Astrophysics Data System (ADS)

    Goldberg, David

    2005-07-01

    We propose measurement of the gravitational "Flexion" signal in ACS cluster images. The flexion, or "arciness" of a lensed background galaxy arises from variations in the lensing field. As a result, it is extremely sensitive to small scale perturbations in the field, and thus, to substructure in clusters. Moreover, because flexion represents gravitationally induced asymmetries in the lensed image, it is completely separable from traditional measurements of shear, which focus on the induced ellipticity of the image, and thus, the two signals may be extracted simultaneously. Since typical galaxies are roughly symmetric upon 180 degree rotation, even a small induced flexion can potentially produce a noticeable effect {Goldberg & Bacon, 2005}. We propose the measurement of substructure within approximately 4 clusters with high-quality ACS data, and will further apply a test of a new tomographic technique whereby comparisons of lensed arcs at different redshifts may be used to estimate the background cosmology, and thus place constraints on the equation of state of dark energy.

  13. 21 CFR 886.4440 - AC-powered magnet.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false AC-powered magnet. 886.4440 Section 886.4440 Food... DEVICES OPHTHALMIC DEVICES Surgical Devices § 886.4440 AC-powered magnet. (a) Identification. An AC-powered magnet is an AC-powered device that generates a magnetic field intended to find and remove...

  14. Built-In Data-Flow Integration Testing in Large-Scale Component-Based Systems

    NASA Astrophysics Data System (ADS)

    Piel, Éric; Gonzalez-Sanchez, Alberto; Gross, Hans-Gerhard

    Modern large-scale component-based applications and service ecosystems are built following a number of different component models and architectural styles, such as the data-flow architectural style. In this style, each building block receives data from a previous one in the flow and sends output data to other components. This organisation expresses information flows adequately, and also favours decoupling between the components, leading to easier maintenance and quicker evolution of the system. Integration testing is a major means to ensure the quality of large systems. Their size and complexity, together with the fact that they are developed and maintained by several stake holders, make Built-In Testing (BIT) an attractive approach to manage their integration testing. However, so far no technique has been proposed that combines BIT and data-flow integration testing. We have introduced the notion of a virtual component in order to realize such a combination. It permits to define the behaviour of several components assembled to process a flow of data, using BIT. Test-cases are defined in a way that they are simple to write and flexible to adapt. We present two implementations of our proposed virtual component integration testing technique, and we extend our previous proposal to detect and handle errors in the definition by the user. The evaluation of the virtual component testing approach suggests that more issues can be detected in systems with data-flows than through other integration testing approaches.

  15. Electroosmotic flow in microchannels with arbitrary geometry and arbitrary distribution of wall charge.

    PubMed

    Xuan, Xiangchun; Li, Dongqing

    2005-09-01

    General solutions are developed for direct current (DC) and alternating current (AC) electroosmotic flows in microfluidic channels with arbitrary cross-sectional geometry and arbitrary distribution of wall charge (zeta potential). The applied AC electric field can also be of arbitrary waveform. By proposing a nondimensional time scale varpi defined as the ratio of the diffusion time of momentum across the electric double-layer thickness to the period of the applied electric field, we demonstrate analytically that the Helmholtz-Smoluchowski electroosmotic velocity is an appropriate slip condition for AC electroosmotic flows in typical microfluidic applications. With this slip condition approach, electroosmotic flows in rectangular and asymmetric trapezoidal microchannels with nonuniform wall charge, as examples, are investigated. The unknown constants in the proposed general solutions are numerically determined with a least-squares method through matching the boundary conditions. We find that the wall charge affects significantly the electroosmotic flow while the channel geometry does not. Moreover, the flow feature is characterized by another nondimensional time scale Omega defined as the ratio of the diffusion time of momentum across the channel hydraulic radius to the period of the applied electric field. The onset of phase shift between AC electroosmotic velocity and applied electric field is also examined analytically.

  16. Optimal Power Flow Pursuit

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

    Dall'Anese, Emiliano; Simonetto, Andrea

    This paper considers distribution networks featuring inverter-interfaced distributed energy resources, and develops distributed feedback controllers that continuously drive the inverter output powers to solutions of AC optimal power flow (OPF) problems. Particularly, the controllers update the power setpoints based on voltage measurements as well as given (time-varying) OPF targets, and entail elementary operations implementable onto low-cost microcontrollers that accompany power-electronics interfaces of gateways and inverters. The design of the control framework is based on suitable linear approximations of the AC power-flow equations as well as Lagrangian regularization methods. Convergence and OPF-target tracking capabilities of the controllers are analytically established. Overall,more » the proposed method allows to bypass traditional hierarchical setups where feedback control and optimization operate at distinct time scales, and to enable real-time optimization of distribution systems.« less

  17. The Cryogenic Anti-Coincidence detector for ATHENA X-IFU: pulse analysis of the AC-S7 single pixel prototype

    NASA Astrophysics Data System (ADS)

    D'Andrea, M.; Argan, A.; Lotti, S.; Macculi, C.; Piro, L.; Biasotti, M.; Corsini, D.; Gatti, F.; Torrioli, G.

    2016-07-01

    The ATHENA observatory is the second large-class mission in ESA Cosmic Vision 2015-2025, with a launch foreseen in 2028 towards the L2 orbit. The mission addresses the science theme "The Hot and Energetic Universe", by coupling a high-performance X-ray Telescope with two complementary focal-plane instruments. One of these is the X-ray Integral Field Unit (X-IFU): it is a TES based kilo-pixel order array able to provide spatially resolved high-resolution spectroscopy (2.5 eV at 6 keV) over a 5 arcmin FoV. The X-IFU sensitivity is degraded by the particles background expected at L2 orbit, which is induced by primary protons of both galactic and solar origin, and mostly by secondary electrons. To reduce the background level and enable the mission science goals, a Cryogenic Anticoincidence (CryoAC) detector is placed < 1 mm below the TES array. It is a 4- pixel TES based detector, with wide Silicon absorbers sensed by Ir:Au TESes. The CryoAC development schedule foresees by Q1 2017 the delivery of a Demonstration Model (DM) to the X-IFU FPA development team. The DM is a single-pixel detector that will address the final design of the CryoAC. It will verify some representative requirements at single-pixel level, especially the detector operation at 50 mK thermal bath and the threshold energy at 20 keV. To reach the final DM design we have developed and tested the AC-S7 prototype, with 1 cm2 absorber area sensed by 65 Ir TESes. Here we will discuss the pulse analysis of this detector, which has been illuminated by the 60 keV line from a 241Am source. First, we will present the analysis performed to investigate pulses timings and spectrum, and to disentangle the athermal component of the pulses from the thermal one. Furthermore, we will show the application to our dataset of an alternative method of pulse processing, based upon Principal Component Analysis (PCA). This kind of analysis allow us to recover better energy spectra than achievable with traditional methods

  18. Experimental investigations on characteristics of boundary layer and control of transition on an airfoil by AC-DBD

    NASA Astrophysics Data System (ADS)

    Geng, Xi; Shi, Zhiwei; Cheng, Keming; Dong, Hao; Zhao, Qun; Chen, Sinuo

    2018-03-01

    Plasma-based flow control is one of the most promising techniques for aerodynamic problems, such as delaying the boundary layer transition. The boundary layer’s characteristics induced by AC-DBD plasma actuators and applied by the actuators to delay the boundary layer transition on airfoil at Ma = 0.3 were experimentally investigated. The PIV measurement was used to study the boundary layer’s characteristics induced by the plasma actuators. The measurement plane, which was parallel to the surface of the actuators and 1 mm above the surface, was involved in the test, including the perpendicular plane. The instantaneous results showed that the induced flow field consisted of many small size unsteady vortices which were eliminated by the time average. The subsequent oil-film interferometry skin friction measurement was conducted on a NASA SC(2)-0712 airfoil at Ma = 0.3. The coefficient of skin friction demonstrates that the plasma actuators successfully delay the boundary layer transition and the efficiency is better at higher driven voltage.

  19. VERIFICATION TESTING OF WET-WEATHER FLOW TECHNOLOGIES

    EPA Science Inventory

    As part of the USEPA's ETV Program, the Wet-Weather Flow (WWF) Technologies Pilot Program verifies the performance of commercial-ready technologies by generating quality-assured data using test protocols developed with broad-based stakeholder input. The availability of a credible...

  20. A Generalised Fault Protection Structure Proposed for Uni-grounded Low-Voltage AC Microgrids

    NASA Astrophysics Data System (ADS)

    Bui, Duong Minh; Chen, Shi-Lin; Lien, Keng-Yu; Jiang, Jheng-Lun

    2016-04-01

    This paper presents three main configurations of uni-grounded low-voltage AC microgrids. Transient situations of a uni-grounded low-voltage (LV) AC microgrid (MG) are simulated through various fault tests and operation transition tests between grid-connected and islanded modes. Based on transient simulation results, available fault protection methods are proposed for main and back-up protection of a uni-grounded AC microgrid. In addition, concept of a generalised fault protection structure of uni-grounded LVAC MGs is mentioned in the paper. As a result, main contributions of the paper are: (i) definition of different uni-grounded LVAC MG configurations; (ii) analysing transient responses of a uni-grounded LVAC microgrid through line-to-line faults, line-to-ground faults, three-phase faults and a microgrid operation transition test, (iii) proposing available fault protection methods for uni-grounded microgrids, such as: non-directional or directional overcurrent protection, under/over voltage protection, differential current protection, voltage-restrained overcurrent protection, and other fault protection principles not based on phase currents and voltages (e.g. total harmonic distortion detection of currents and voltages, using sequence components of current and voltage, 3I0 or 3V0 components), and (iv) developing a generalised fault protection structure with six individual protection zones to be suitable for different uni-grounded AC MG configurations.

  1. Strongly nonlinear dynamics of electrolytes in large ac voltages.

    PubMed

    Højgaard Olesen, Laurits; Bazant, Martin Z; Bruus, Henrik

    2010-07-01

    We study the response of a model microelectrochemical cell to a large ac voltage of frequency comparable to the inverse cell relaxation time. To bring out the basic physics, we consider the simplest possible model of a symmetric binary electrolyte confined between parallel-plate blocking electrodes, ignoring any transverse instability or fluid flow. We analyze the resulting one-dimensional problem by matched asymptotic expansions in the limit of thin double layers and extend previous work into the strongly nonlinear regime, which is characterized by two features--significant salt depletion in the electrolyte near the electrodes and, at very large voltage, the breakdown of the quasiequilibrium structure of the double layers. The former leads to the prediction of "ac capacitive desalination" since there is a time-averaged transfer of salt from the bulk to the double layers, via oscillating diffusion layers. The latter is associated with transient diffusion limitation, which drives the formation and collapse of space-charge layers, even in the absence of any net Faradaic current through the cell. We also predict that steric effects of finite ion sizes (going beyond dilute-solution theory) act to suppress the strongly nonlinear regime in the limit of concentrated electrolytes, ionic liquids, and molten salts. Beyond the model problem, our reduced equations for thin double layers, based on uniformly valid matched asymptotic expansions, provide a useful mathematical framework to describe additional nonlinear responses to large ac voltages, such as Faradaic reactions, electro-osmotic instabilities, and induced-charge electrokinetic phenomena.

  2. Jet-Surface Interaction Test: Flow Measurements Results

    NASA Technical Reports Server (NTRS)

    Brown, Cliff; Wernet, Mark

    2014-01-01

    Modern aircraft design often puts the engine exhaust in close proximity to the airframe surfaces. Aircraft noise prediction tools must continue to develop in order to meet the challenges these aircraft present. The Jet-Surface Interaction Tests have been conducted to provide a comprehensive quality set of experimental data suitable for development and validation of these exhaust noise prediction methods. Flow measurements have been acquired using streamwise and cross-stream particle image velocimetry (PIV) and fluctuating surface pressure data acquired using flush mounted pressure transducers near the surface trailing edge. These data combined with previously reported far-field and phased array noise measurements represent the first step toward the experimental data base. These flow data are particularly applicable to development of noise prediction methods which rely on computational fluid dynamics to uncover the flow physics. A representative sample of the large flow data set acquired is presented here to show how a surface near a jet affects the turbulent kinetic energy in the plume, the spatial relationship between the jet plume and surface needed to generate surface trailing-edge noise, and differences between heated and unheated jet flows with respect to surfaces.

  3. Design verification and cold-flow modeling test report

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

    Not Available

    1993-07-01

    This report presents a compilation of the following three test reports prepared by TRW for Alaska Industrial Development and Export Authority (AIDEA) as part of the Healy Clean Coal Project, Phase 1 Design of the TRW Combustor and Auxiliary Systems, which is co-sponsored by the Department of Energy under the Clean Coal Technology 3 Program: (1) Design Verification Test Report, dated April 1993, (2) Combustor Cold Flow Model Report, dated August 28, 1992, (3) Coal Feed System Cold Flow Model Report, October 28, 1992. In this compilation, these three reports are included in one volume consisting of three parts, andmore » TRW proprietary information has been excluded.« less

  4. Multi-isotope SPECT imaging of the 225Ac decay chain: feasibility studies

    NASA Astrophysics Data System (ADS)

    Robertson, A. K. H.; Ramogida, C. F.; Rodríguez-Rodríguez, C.; Blinder, Stephan; Kunz, Peter; Sossi, Vesna; Schaffer, Paul

    2017-06-01

    Effective use of the {}225Ac decay chain in targeted internal radioimmunotherapy requires the retention of both {}225Ac and progeny isotopes at the target site. Imaging-based pharmacokinetic tests of these pharmaceuticals must therefore separately yet simultaneously image multiple isotopes that may not be colocalized despite being part of the same decay chain. This work presents feasibility studies demonstrating the ability of a microSPECT/CT scanner equipped with a high energy collimator to simultaneously image two components of the {}225Ac decay chain: {}221Fr (218 keV) and {}213Bi (440 keV). Image quality phantoms were used to assess the performance of two collimators for simultaneous {}221Fr and {}213Bi imaging in terms of contrast and noise. A hotrod resolution phantom containing clusters of thin rods with diameters ranging between 0.85 and 1.70 mm was used to assess resolution. To demonstrate ability to simultaneously image dynamic {}221Fr and {}213Bi activity distributions, a phantom containing a {}213Bi generator from {}225Ac was imaged. These tests were performed with two collimators, a high-energy ultra-high resolution (HEUHR) collimator and an ultra-high sensitivity (UHS) collimator. Values consistent with activity concentrations determined independently via gamma spectroscopy were observed in high activity regions of the images. In hotrod phantom images, the HEUHR collimator resolved all rods for both {}221Fr and {}213Bi images. With the UHS collimator, no rods were resolvable in {}213Bi images and only rods  ⩾1.3 mm were resolved in {}221Fr images. After eluting the {}213Bi generator, images accurately visualized the reestablishment of transient equilibrium of the {}225Ac decay chain. The feasibility of evaluating the pharmacokinetics of the {}225Ac decay chain in vivo has been demonstrated. This presented method requires the use of a high-performance high-energy collimator.

  5. Development of Flow Boiling and Condensation Experiment on the International Space Station- Normal and Low Gravity Flow Boiling Experiment Development and Test Results

    NASA Technical Reports Server (NTRS)

    Nahra, Henry K.; Hall, Nancy R.; Hasan, Mohammad M.; Wagner, James D.; May, Rochelle L.; Mackey, Jeffrey R.; Kolacz, John S.; Butcher, Robert L.; Frankenfield, Bruce J.; Mudawar, Issam; hide

    2013-01-01

    Flow boiling and condensation have been identified as two key mechanisms for heat transport that are vital for achieving weight and volume reduction as well as performance enhancement in future space systems. Since inertia driven flows are demanding on power usage, lower flows are desirable. However, in microgravity, lower flows are dominated by forces other than inertia (like the capillary force). It is of paramount interest to investigate limits of low flows beyond which the flow is inertial enough to be gravity independent. One of the objectives of the Flow Boiling and Condensation Flight Experiment sets to investigate these limits for flow boiling and condensation. A two-phase flow loop consisting of a Flow Boiling Module and two Condensation Modules has been developed to experimentally study flow boiling condensation heat transfer in the reduced gravity environment provided by the reduced gravity platform. This effort supports the development of a flow boiling and condensation facility for the International Space Station (ISS). The closed loop test facility is designed to deliver the test fluid, FC-72 to the inlet of any one of the test modules at specified thermodynamic and flow conditions. The zero-g-aircraft tests will provide subcooled and saturated flow boiling critical heat flux and flow condensation heat transfer data over wide range of flow velocities. Additionally, these tests will verify the performance of all gravity sensitive components, such as evaporator, condenser and accumulator associated with the two-phase flow loop. We will present in this paper the breadboard development and testing results which consist of detailed performance evaluation of the heater and condenser combination in reduced and normal gravity. We will also present the design of the reduced gravity aircraft rack and the results of the ground flow boiling heat transfer testing performed with the Flow Boiling Module that is designed to investigate flow boiling heat transfer and

  6. Active Flow Control with Thermoacoustic Actuators

    DTIC Science & Technology

    2014-01-31

    AC power has been shown to produce large-amplitude acoustic waves [6]. The input AC current sinusoidally heats this device due to joule heating and...conventional metals, the heat capacity value for carbon-based material (carbon nanotubes/graphene) in consideration here is at least 2 orders of...magnitude smaller. Since the output acoustic power delivered to the surrounding flow field is related inversely to the material heat capacity C (i.e., Poutput

  7. Scaled Rocket Testing in Hypersonic Flow

    NASA Technical Reports Server (NTRS)

    Dufrene, Aaron; MacLean, Matthew; Carr, Zakary; Parker, Ron; Holden, Michael; Mehta, Manish

    2015-01-01

    NASA's Space Launch System (SLS) uses four clustered liquid rocket engines along with two solid rocket boosters. The interaction between all six rocket exhaust plumes will produce a complex and severe thermal environment in the base of the vehicle. This work focuses on a recent 2% scale, hot-fire SLS base heating test. These base heating tests are short-duration tests executed with chamber pressures near the full-scale values with gaseous hydrogen/oxygen engines and RSRMV analogous solid propellant motors. The LENS II shock tunnel/Ludwieg tube tunnel was used at or near flight duplicated conditions up to Mach 5. Model development was strongly based on the Space Shuttle base heating tests with several improvements including doubling of the maximum chamber pressures and duplication of freestream conditions. Detailed base heating results are outside of the scope of the current work, rather test methodology and techniques are presented along with broader applicability toward scaled rocket testing in supersonic and hypersonic flow.

  8. The AC 2000.2 Catalogue

    NASA Astrophysics Data System (ADS)

    Urban, S. E.; Corbin, T. E.; Wycoff, G. L.; Makarov, V. V.; Høg, E.; Fabricius, C.

    2001-12-01

    For over 100 years, the international project known as the Astrographic Catalogue -- which involved 20 observatories tasked to photograph the sky -- has held an unfulfilled promised of yielding a wealth of astrometric information. This promise was not realized due to the inadequate reductions of the project's plates. However, in 1997 the U.S. Naval Observatory (USNO) completed the reductions of the 22,660 plates. That catalogue, named the AC 2000, contained positions and magnitudes for 4.6 million stars down to about v magnitude 12.5. Due to the early epochs of the data -- averaging 1907 -- and the positional accuracies -- between 150 and 400 milliarcseconds -- the data are extremely valuable in computing proper motions. In 1997, these positions were used to form the proper motions of the ACT Reference Catalogue. In 1999, USNO and Copenhagen University Observatory (CUO) partnered to create the Tycho-2 Catalogue. The CUO group re-analyzed the data from the Tycho experiment on the Hipparcos satellite. The USNO group re-analyzed over 140 positional catalogs which were combined with the expanded Tycho positions from the CUO group to compute the Tycho-2 proper motions. The largest contributor to these proper motions was the re-analyzed Astrographic Catalogue; the latest version being known as the AC 2000.2 Catalogue. There are two major differences between the AC 2000 and the AC 2000.2. First, the reference catalog used in AC 2000.2 was an expanded version of the Astrographic Catalogue Reference Stars that was rigorously derived on the Hipparcos Celestial Reference Frame. The second is that AC 2000.2 contains photometry from Tycho-2, where available. A description of the AC 2000.2 Catalogue, the reduction techniques used, how it compares with the 1997 version, and information on obtaining the data will be presented.

  9. Final Report for the Advanced Camera for Surveys (ACS) from Ball Aerospace and Technologies Corporation

    NASA Technical Reports Server (NTRS)

    Volmer, Paul; Sullivan, Pam (Technical Monitor)

    2003-01-01

    The Advanced Camera for Surveys ACS was launched aboard the Space Shuttle Columbia just before dawn on March 1, 2002. After successfully docking with the Hubble Space Telescope (HST), several components were replaced. One of the components was the Advanced Camera for Surveys built by Ball Aerospace & Technologies Corp. (BATC) in Boulder, Colorado. Over the life of the HST contract at BATC hundreds of employees had the pleasure of working on the concept, design, fabrication, assembly and test of ACS. Those employees thank NASA - Goddard Space Flight Center and the science team at Johns Hopkins University (JHU) for the opportunity to participate in building a great science instrument for HST. After installation in HST a mini-functional test was performed and later a complete functional test. ACS performed well and has continued performing well since then. One of the greatest rewards for the BATC employees is a satisfied science team. Following is an excerpt from the JHU final report, "The foremost promise of ACS was to increase Hubble's capability for surveys in the near infrared by a factor of 10. That promise was kept. "

  10. Initial NIST AC QHR Measurements

    PubMed Central

    Cage, M. E.; Shields, S. H.; Jeffery, A.

    2004-01-01

    We demonstrate that dc quantized Hall resistance (dc QHR) guideline properties and dc and ac QHR values can be measured without changing sample probe lead connections at the QHR device, and report ac QHR values that converge to the dc QHR value when using four-terminal-pair ac QHR measurements. This was accomplished during one cooldown using single-series and quadruple-series connections outside the sample probe. The QHR was measured from 0 Hz to 5500 Hz in 1:1 ratio at 20 µA to ±1 part in 107 uncertainties with a poor-quality QHR device. A good device would allow an order of magnitude smaller uncertainties over this frequency range. We exchanged positions of the QHR device and reference resistor in the bridge and remeasured the resistance ratios to remove dominant ac bridge effects. PMID:27366620

  11. Analysis and Assessment of Operation Risk for Hybrid AC/DC Power System based on the Monte Carlo Method

    NASA Astrophysics Data System (ADS)

    Hu, Xiaojing; Li, Qiang; Zhang, Hao; Guo, Ziming; Zhao, Kun; Li, Xinpeng

    2018-06-01

    Based on the Monte Carlo method, an improved risk assessment method for hybrid AC/DC power system with VSC station considering the operation status of generators, converter stations, AC lines and DC lines is proposed. According to the sequential AC/DC power flow algorithm, node voltage and line active power are solved, and then the operation risk indices of node voltage over-limit and line active power over-limit are calculated. Finally, an improved two-area IEEE RTS-96 system is taken as a case to analyze and assessment its operation risk. The results show that the proposed model and method can intuitively and directly reflect the weak nodes and weak lines of the system, which can provide some reference for the dispatching department.

  12. Flow-induced vibration testing of replacement thermowell designs

    NASA Astrophysics Data System (ADS)

    Haslinger, K. H.

    2003-09-01

    Inconel 600 Primary Water Stress Corrosion Cracking (PWSCC) in Nuclear Pressurized Water Reactors (PWRs) has necessitated the repair/replacement of various small bore nozzles. These repairs/replacements must be designed to avoid unwanted vibrations. So, to this end, new RTD-Thermowell-Nozzle replacement designs were developed and subjected to flow testing over a velocity range from 9.14 to 33.53m/s (30-110ft/s), and temperatures ranging from 121°C to 316°C (250-600°F). The replacement nozzles are welded on the pipe OD, rather than on the pipe ID. A split, tapered ferrule is used to support the nozzle tip inside the pipe bore. This maintains high thermowell tip-resonance frequencies with the objective of avoiding self-excitation from vortex shedding that is believed to have caused failures in an earlier design during initial, precritical plant startup testing. The flow testing was complicated by the small size of the thermowell tips (5.08mm or 0.2in ID), which necessitated use of a complement of low temperature and high temperature instrumentation. Since the high temperature device had an internal resonance (750Hz) within the frequency range of interest (0-2500Hz), adequate sensor correlations had to be derived from low temperature tests. The current nozzle/thermowell design was tested concurrently with two slight variations of the replacement design. The acceleration signals were acquired during incremental and continuous flow sweeps, nominally at 5kHz sampling rates and for time domain processing as high as 25kHz. Whereas vortex-shedding frequencies were predicted to prevail between 400 and 1500Hz, no such response was observed at these frequencies. Rather, the thermowell tips responded due to turbulent buffeting with a peak response that was related directly to flow velocity. Lift direction response was always larger than drag direction response. The thermowell tips also responded at their natural tip frequencies in a narrow band random fashion. At the higher

  13. Imaging ac losses in superconducting films via scanning Hall probe microscopy

    NASA Astrophysics Data System (ADS)

    Dinner, Rafael B.; Moler, Kathryn A.; Feldmann, D. Matthew; Beasley, M. R.

    2007-04-01

    Various local probes have been applied to understanding current flow through superconducting films, which are often surprisingly inhomogeneous. Here, we show that magnetic imaging allows quantitative reconstruction of both current density J and electric field E resolved in time and space in a film carrying subcritical ac current. Current reconstruction entails inversion of the Biot-Savart law, while electric fields are reconstructed using Faraday’s law. We describe the corresponding numerical procedures, largely adapting existing work to the case of a strip carrying ac current, but including other methods of obtaining the complete electric field from the inductive portion determined by Faraday’s law. We also delineate the physical requirements behind the mathematical transformations. We then apply the procedures to images of a strip of YBa2Cu3O7-δ carrying an ac current at 400Hz . Our scanning Hall probe microscope produces a time series of magnetic images of the strip with 1μm spatial resolution and 25μs time resolution. Combining the reconstructed J and E , we obtain a complete characterization including local critical current density, E-J curves, and power losses. This analysis has a range of applications from fundamental studies of vortex dynamics to practical coated conductor development.

  14. 40 CFR 86.1773-99 - Test sequence; general requirements.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... test simulation procedures, AC1 and AC2, for the 2001 to 2003 model years only. If a manufacturer desires to conduct an alternative SC03 test simulation other than AC1 and AC2, or the AC1 and AC2 simulations for the 2004 and subsequent model years, the simulation test procedure must be approved in advance...

  15. 40 CFR 86.1773-99 - Test sequence; general requirements.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... test simulation procedures, AC1 and AC2, for the 2001 to 2003 model years only. If a manufacturer desires to conduct an alternative SC03 test simulation other than AC1 and AC2, or the AC1 and AC2 simulations for the 2004 and subsequent model years, the simulation test procedure must be approved in advance...

  16. 40 CFR 86.1773-99 - Test sequence; general requirements.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... test simulation procedures, AC1 and AC2, for the 2001 to 2003 model years only. If a manufacturer desires to conduct an alternative SC03 test simulation other than AC1 and AC2, or the AC1 and AC2 simulations for the 2004 and subsequent model years, the simulation test procedure must be approved in advance...

  17. Tracer Tests in the Fractured Rock to Investigate Preferential Groundwater Flow

    NASA Astrophysics Data System (ADS)

    Chan, W.; Chung, L.; Lee, T.; Liu, C.; Chia, Y.; Teng, M.

    2012-12-01

    Hydraulic tests are often used to obtain hydraulic conductivity in the aquifer. Test results usually reflect the average hydraulic conductivity in the surrounding strat. However, in fractured rock, groundwater flows primarily through a few fractures. Saltwater tracer test can be used to detect the direction of groundwater flow, but it was difficult to know the hydraulic connectivity between fractures. In this study, we use a variety of field tests, including tracer test, hydraulic test, and heat-pulse flowmeter test, to locate the permeable fractures and detect the hydraulic connections between boreholes. There are eight test wells and two observation wells on field experimental site in central Taiwan. Geological survey results show that there are at least three sets of joint planes. In order to realize the location of the preferential pathway of groundwater flow, heat-pulse flowmeter measurement was adopted to identify the depth of permeable fractures. Multi-well pumping test was also performed to investigate the hydraulic connectivity between these wells. Tracer tests were then used to detect the hydraulic connectivity of permeable fractures between two wells. Injection of nano zero valent iron in one well and and collection of iron tracer with a magnet array in the other well can specifically locate the permeable fracture and determine the connectivity. Saltwater tracer test result can be used to support that of nano-iron tracer test, and verify the relationship between well water conductivity increases and rock fracture location. The results show that tracer test is a useful tool to investigate the preferential groundwater flow in the fractured rock, but it is essential to flush the mud in fractures prior to the test.

  18. Simultaneous distribution of AC and DC power

    DOEpatents

    Polese, Luigi Gentile

    2015-09-15

    A system and method for the transport and distribution of both AC (alternating current) power and DC (direct current) power over wiring infrastructure normally used for distributing AC power only, for example, residential and/or commercial buildings' electrical wires is disclosed and taught. The system and method permits the combining of AC and DC power sources and the simultaneous distribution of the resulting power over the same wiring. At the utilization site a complementary device permits the separation of the DC power from the AC power and their reconstruction, for use in conventional AC-only and DC-only devices.

  19. Frequency-dependent laminar electroosmotic flow in a closed-end rectangular microchannel.

    PubMed

    Marcos; Yang, C; Ooi, K T; Wong, T N; Masliyah, J H

    2004-07-15

    This article presents an analysis of the frequency- and time-dependent electroosmotic flow in a closed-end rectangular microchannel. An exact solution to the modified Navier-Stokes equation governing the ac electroosmotic flow field is obtained by using the Green's function formulation in combination with a complex variable approach. An analytical expression for the induced backpressure gradient is derived. With the Debye-Hückel approximation, the electrical double-layer potential distribution in the channel is obtained by analytically solving the linearized two-dimensional Poisson-Boltzmann equation. Since the counterparts of the flow rate and the electrical current are shown to be linearly proportional to the applied electric field and the pressure gradient, Onsager's principle of reciprocity is demonstrated for transient and ac electroosmotic flows. The time evolution of the electroosmotic flow and the effect of a frequency-dependent ac electric field on the oscillating electroosmotic flow in a closed-end rectangular microchannel are examined. Specifically, the induced pressure gradient is analyzed under effects of the channel dimension and the frequency of electric field. In addition, based on the Stokes second problem, the solution of the slip velocity approximation is presented for comparison with the results obtained from the analytical scheme developed in this study. Copyright 2004 Elsevier Inc.

  20. An in vitro test bench reproducing coronary blood flow signals.

    PubMed

    Chodzyński, Kamil Jerzy; Boudjeltia, Karim Zouaoui; Lalmand, Jacques; Aminian, Adel; Vanhamme, Luc; de Sousa, Daniel Ribeiro; Gremmo, Simone; Bricteux, Laurent; Renotte, Christine; Courbebaisse, Guy; Coussement, Grégory

    2015-08-07

    It is a known fact that blood flow pattern and more specifically the pulsatile time variation of shear stress on the vascular wall play a key role in atherogenesis. The paper presents the conception, the building and the control of a new in vitro test bench that mimics the pulsatile flows behavior based on in vivo measurements. An in vitro cardiovascular simulator is alimented with in vivo constraints upstream and provided with further post-processing analysis downstream in order to mimic the pulsatile in vivo blood flow quantities. This real-time controlled system is designed to perform real pulsatile in vivo blood flow signals to study endothelial cells' behavior under near physiological environment. The system is based on an internal model controller and a proportional-integral controller that controls a linear motor with customized piston pump, two proportional-integral controllers that control the mean flow rate and temperature of the medium. This configuration enables to mimic any resulting blood flow rate patterns between 40 and 700 ml/min. In order to feed the system with reliable periodic flow quantities in vivo measurements were performed. Data from five patients (1 female, 4 males; ages 44-63) were filtered and post-processed using the Newtonian Womersley's solution. These resulting flow signals were compared with 2D axisymmetric, numerical simulation using a Carreau non-Newtonian model to validate the approximation of a Newtonian behavior. This in vitro test bench reproduces the measured flow rate time evolution and the complexity of in vivo hemodynamic signals within the accuracy of the relative error below 5%. This post-processing method is compatible with any real complex in vivo signal and demonstrates the heterogeneity of pulsatile patterns in coronary arteries among of different patients. The comparison between analytical and numerical solution demonstrate the fair quality of the Newtonian Womersley's approximation. Therefore, Womersley's solution

  1. Development of software to improve AC power quality on large spacecraft

    NASA Technical Reports Server (NTRS)

    Kraft, L. Alan

    1991-01-01

    To insure the reliability of a 20 kHz, alternating current (AC) power system on spacecraft, it is essential to analyze its behavior under many adverse operating conditions. Some of these conditions include overloads, short circuits, switching surges, and harmonic distortions. Harmonic distortions can become a serious problem. It can cause malfunctions in equipment that the power system is supplying, and, during distortions such as voltage resonance, it can cause equipment and insulation failures due to the extreme peak voltages. To address the harmonic distortion issue, work was begun under the 1990 NASA-ASEE Summer Faculty Fellowship Program. Software, originally developed by EPRI, called HARMFLO, a power flow program capable of analyzing harmonic conditions on three phase, balanced, 60 Hz AC power systems, was modified to analyze single phase, 20 kHz, AC power systems. Since almost all of the equipment used on spacecraft power systems is electrically different from equipment used on terrestrial power systems, it was also necessary to develop mathematical models for the equipment to be used on the spacecraft. The modelling was also started under the same fellowship work period. Details of the modifications and models completed during the 1990 NASA-ASEE Summer Faculty Fellowship Program can be found in a project report. As a continuation of the work to develop a complete package necessary for the full analysis of spacecraft AC power system behavior, deployment work has continued through NASA Grant NAG3-1254. This report details the work covered by the above mentioned grant.

  2. On utilizing alternating current-flow field effect transistor for flexibly manipulating particles in microfluidics and nanofluidics

    PubMed Central

    Liu, Weiyu; Shao, Jinyou; Ren, Yukun; Liu, Jiangwei; Tao, Ye; Jiang, Hongyuan; Ding, Yucheng

    2016-01-01

    By imposing a biased gate voltage to a center metal strip, arbitrary symmetry breaking in induced-charge electroosmotic flow occurs on the surface of this planar gate electrode, a phenomenon termed as AC-flow field effect transistor (AC-FFET). In this work, the potential of AC-FFET with a shiftable flow stagnation line to flexibly manipulate micro-nano particle samples in both a static and continuous flow condition is demonstrated via theoretical analysis and experimental validation. The effect of finite Debye length of induced double-layer and applied field frequency on the manipulating flexibility factor for static condition is investigated, which indicates AC-FFET turns out to be more effective for achieving a position-controllable concentrating of target nanoparticle samples in nanofluidics compared to the previous trial in microfluidics. Besides, a continuous microfluidics-based particle concentrator/director is developed to deal with incoming analytes in dynamic condition, which exploits a design of tandem electrode configuration to consecutively flow focus and divert incoming particle samples to a desired downstream branch channel, as prerequisite for a following biochemical analysis. Our physical demonstrations with AC-FFET prove valuable for innovative designs of flexible electrokinetic frameworks, which can be conveniently integrated with other microfluidic or nanofluidic components into a complete lab-on-chip diagnostic platform due to a simple electrode structure. PMID:27190570

  3. On utilizing alternating current-flow field effect transistor for flexibly manipulating particles in microfluidics and nanofluidics.

    PubMed

    Liu, Weiyu; Shao, Jinyou; Ren, Yukun; Liu, Jiangwei; Tao, Ye; Jiang, Hongyuan; Ding, Yucheng

    2016-05-01

    By imposing a biased gate voltage to a center metal strip, arbitrary symmetry breaking in induced-charge electroosmotic flow occurs on the surface of this planar gate electrode, a phenomenon termed as AC-flow field effect transistor (AC-FFET). In this work, the potential of AC-FFET with a shiftable flow stagnation line to flexibly manipulate micro-nano particle samples in both a static and continuous flow condition is demonstrated via theoretical analysis and experimental validation. The effect of finite Debye length of induced double-layer and applied field frequency on the manipulating flexibility factor for static condition is investigated, which indicates AC-FFET turns out to be more effective for achieving a position-controllable concentrating of target nanoparticle samples in nanofluidics compared to the previous trial in microfluidics. Besides, a continuous microfluidics-based particle concentrator/director is developed to deal with incoming analytes in dynamic condition, which exploits a design of tandem electrode configuration to consecutively flow focus and divert incoming particle samples to a desired downstream branch channel, as prerequisite for a following biochemical analysis. Our physical demonstrations with AC-FFET prove valuable for innovative designs of flexible electrokinetic frameworks, which can be conveniently integrated with other microfluidic or nanofluidic components into a complete lab-on-chip diagnostic platform due to a simple electrode structure.

  4. Application of Background Oriented Schlieren for Altitude Testing of Rocket Engines

    NASA Technical Reports Server (NTRS)

    Wernet, Mark P.; Stiegemeier, Benjamin R.

    2017-01-01

    A series of experiments was performed to determine the feasibility of using the Background Oriented Schlieren, BOS, flow visualization technique to image a simulated, small, rocket engine, plume under altitude test conditions. Testing was performed at the NASA Glenn Research Centers Altitude Combustion Stand, ACS, using nitrogen as the exhaust gas simulant. Due to limited optical access to the facility test capsule, all of the hardware required to conduct the BOS were located inside the vacuum chamber. During the test series 26 runs were performed using two different nozzle configurations with pressures in the test capsule around 0.3 psia. No problems were encountered during the test series resulting from the optical hardware being located in the test capsule and acceptable resolution images were captured. The test campaign demonstrated the ability of using the BOS technique for small, rocket engine, plume flow visualization during altitude testing.

  5. Liquid Hydrogen Recirculation System for Forced Flow Cooling Test of Superconducting Conductors

    NASA Astrophysics Data System (ADS)

    Shirai, Y.; Kainuma, T.; Shigeta, H.; Shiotsu, M.; Tatsumoto, H.; Naruo, Y.; Kobayashi, H.; Nonaka, S.; Inatani, Y.; Yoshinaga, S.

    2017-12-01

    The knowledge of forced flow heat transfer characteristics of liquid hydrogen (LH2) is important and necessary for design and cooling analysis of high critical temperature superconducting devices. However, there are few test facilities available for LH2 forced flow cooling for superconductors. A test system to provide a LH2 forced flow (∼10 m/s) of a short period (less than 100 s) has been developed. The test system was composed of two LH2 tanks connected by a transfer line with a controllable valve, in which the forced flow rate and its period were limited by the storage capacity of tanks. In this paper, a liquid hydrogen recirculation system, which was designed and fabricated in order to study characteristics of superconducting cables in a stable forced flow of liquid hydrogen for longer period, was described. This LH2 loop system consists of a centrifugal pump with dynamic gas bearings, a heat exchanger which is immersed in a liquid hydrogen tank, and a buffer tank where a test section (superconducting wires or cables) is set. The buffer tank has LHe cooled superconducting magnet which can produce an external magnetic field (up to 7T) at the test section. A performance test was conducted. The maximum flow rate was 43.7 g/s. The lowest temperature was 22.5 K. It was confirmed that the liquid hydrogen can stably circulate for 7 hours.

  6. Safety and diagnostic systems on the Liquid Lithium Test Stand (LLTS)

    NASA Astrophysics Data System (ADS)

    Schwartz, J. A.; Jaworski, M. A.; Ellis, R.; Kaita, R.; Mozulay, R.

    2013-10-01

    The Liquid Lithium Test Stand (LLTS) is a test bed for development of flowing liquid lithium systems for plasma-facing components at PPPL. LLTS is designed to test operation of liquid lithium under vacuum, including flowing, solidifying (such as would be the case at the end of plasma operations), and re-melting. Constructed of stainless steel, LLTS is a closed loop of pipe with two reservoirs and a pump, as well as diagnostics for temperature, flow rate, and pressure. Since liquid lithium is a highly reactive material, special care must be taken when designing such a system. These include a permanent-magnet MHD pump and MHD flow meter that have no mechanical components in direct contact with the liquid lithium. The LLTS also includes an expandable 24-channel leak-detector interlock system which cuts power to heaters and the pump if any lithium leaks from a pipe joint. Design for the interlock systems and flow meter are presented. This work is supported by US DOE Contract DE-AC02-09CH11466.

  7. New Composites LnBDC@AC and CB[6]@AC: From Design toward Selective Adsorption of Methylene Blue or Methyl Orange

    PubMed Central

    Santos, Guilherme de C.; Barros, Amanda L.; de Oliveira, Carlos A. F.; da Luz, Leonis L.; da Silva, Fausthon F.; Demets, Grégoire J.-F.; Alves Júnior, Severino

    2017-01-01

    New porous composites LnBDC@AC (AC = Activated carbon, Ln = Eu and Gd and BDC = 1,4-benzenedicaboxylate) and CB[6]@AC (CB[6] = Cucurbit[6]uril) were obtained using hydrothermal route. The LnBDC and CB[B] are located inside the pore of the carbon materials as was observed in SEM-EDS, XRPD and FT-IR analysis. Porosimetry analysis showed values typically between AC and LnBDC material, with pore size and surface area, respectively, 29,56 Å and 353.98 m2g-1 for LnBDC@AC and 35,53 Å and 353.98 m2g-1 for CB[6]@AC. Both materials showed good absorptive capacity of metil orange (MO) and methylene blue (MB) with selectivity as a function of pH. For acid pH, both materials present selectivity by MB and alkaline pH for MO, with notable performance for CB[6]@AC. Additionally, europium luminescence was used as structural probe to investigate the coordination environment of Eu3+ ions in the EuBDC@AC composite after adsorption experiment. PMID:28107440

  8. Measurements of Turbulent Flow Field in Separate Flow Nozzles with Enhanced Mixing Devices - Test Report

    NASA Technical Reports Server (NTRS)

    Bridges, James

    2002-01-01

    As part of the Advanced Subsonic Technology Program, a series of experiments was conducted at NASA Glenn Research Center on the effect of mixing enhancement devices on the aeroacoustic performance of separate flow nozzles. Initial acoustic evaluations of the devices showed that they reduced jet noise significantly, while creating very little thrust loss. The explanation for the improvement required that turbulence measurements, namely single point mean and RMS statistics and two-point spatial correlations, be made to determine the change in the turbulence caused by the mixing enhancement devices that lead to the noise reduction. These measurements were made in the summer of 2000 in a test program called Separate Nozzle Flow Test 2000 (SFNT2K) supported by the Aeropropulsion Research Program at NASA Glenn Research Center. Given the hot high-speed flows representative of a contemporary bypass ratio 5 turbofan engine, unsteady flow field measurements required the use of an optical measurement method. To achieve the spatial correlations, the Particle Image Velocimetry technique was employed, acquiring high-density velocity maps of the flows from which the required statistics could be derived. This was the first successful use of this technique for such flows, and shows the utility of this technique for future experimental programs. The extensive statistics obtained were likewise unique and give great insight into the turbulence which produces noise and how the turbulence can be modified to reduce jet noise.

  9. Improved Tribological Performance of Amorphous Carbon (a-C) Coating by ZrO2 Nanoparticles

    PubMed Central

    Tang, Jinzhu; Ding, Qi; Zhang, Songwei; Wu, Guizhi; Hu, Litian

    2016-01-01

    Nanomaterials, such as Graphene, h-BN nanoparticles and MoS2 nanotubes, have shown their ability in improving the tribological performance of amorphous carbon (a-C) coatings. In the current study, the effectiveness of ZrO2 nanoparticles (ZrO2-NPs) in lubricating the self-mated nonhydrogenated a-C contacts was investigated in boundary lubrication regime. The results showed that 13% less friction and 50% less wear compared to the base oil were achieved by employing ZrO2-NPs in the base oil in self-mated a-C contacts. Via analyzing the ZrO2-NPs and the worn a-C surface after tests, it was found that the improved lubrication by ZrO2-NPs was based on “polishing effects”, which is a new phenomenon observed between a-C and nanoparticles. Under the “polishing effect”, micro-plateaus with extremely smooth surface and uniform height were produced on the analyzed a-C surface. The resulting topography of the a-C coating is suitable for ZrO2-NPs to act as nano-bearings between rubbing surfaces. Especially, the ZrO2-NPs exhibited excellent mechanical and chemical stability, even under the severe service condition, suggesting that the combination of nonhydrogenated a-C coating with ZrO2-NPs is an effective, long lasting and environment-friendly lubrication solution. PMID:28773916

  10. Soap-film flow induced by electric fields in asymmetric frames.

    PubMed

    Mollaei, S; Nasiri, M; Soltanmohammadi, N; Shirsavar, R; Ramos, A; Amjadi, A

    2018-04-01

    Net fluid flow of soap films induced by (ac or dc) electric fields in asymmetric frames is presented. Previous experiments of controllable soap film flow required the simultaneous use of an electrical current passing through the film and an external electric field or the use of nonuniform ac electric fields. Here a single voltage difference generates both the electrical current going through the film and the electric field that actuates on the charge induced on the film. The film is set into global motion due to the broken symmetry that appears by the use of asymmetric frames. If symmetric frames are used, the film flow is not steady but time dependent and irregular. Finally, we study numerically these film flows by employing the model of charge induction in ohmic liquids.

  11. Soap-film flow induced by electric fields in asymmetric frames

    NASA Astrophysics Data System (ADS)

    Mollaei, S.; Nasiri, M.; Soltanmohammadi, N.; Shirsavar, R.; Ramos, A.; Amjadi, A.

    2018-04-01

    Net fluid flow of soap films induced by (ac or dc) electric fields in asymmetric frames is presented. Previous experiments of controllable soap film flow required the simultaneous use of an electrical current passing through the film and an external electric field or the use of nonuniform ac electric fields. Here a single voltage difference generates both the electrical current going through the film and the electric field that actuates on the charge induced on the film. The film is set into global motion due to the broken symmetry that appears by the use of asymmetric frames. If symmetric frames are used, the film flow is not steady but time dependent and irregular. Finally, we study numerically these film flows by employing the model of charge induction in ohmic liquids.

  12. 21 CFR 886.1850 - AC-powered slitlamp biomicroscope.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false AC-powered slitlamp biomicroscope. 886.1850... (CONTINUED) MEDICAL DEVICES OPHTHALMIC DEVICES Diagnostic Devices § 886.1850 AC-powered slitlamp biomicroscope. (a) Identification. An AC-powered slitlamp biomicroscope is an AC-powered device that is a...

  13. Predominance of the ac variant in K88-positive Escherichia coli isolates from swine.

    PubMed Central

    Westerman, R B; Mills, K W; Phillips, R M; Fortner, G W; Greenwood, J M

    1988-01-01

    Monoclonal antibodies to K88ac and K88ab were used in enzyme-linked immunosorbent assays on Escherichia coli cultures known to produce K88 pili. A total of 415 K88-positive E. coli isolates from nine states were all found to be the K88ac variant. The cultures tested were isolated during the years 1976 to 1985. PMID:3277990

  14. Boeing engineers perform air flow balance testing.

    NASA Image and Video Library

    2017-10-05

    Boeing engineers, Chris Chapman, left, Greg Clark, center, and Ashesh Patel, right, perform air flow balance testing on NASA's new Basic Express Racks. The racks, developed at Marshall, will expand the capabilities for science research aboard the International Space Station. Delivery to the station is scheduled for late 2018.

  15. Load-Flow in Multiphase Distribution Networks: Existence, Uniqueness, Non-Singularity, and Linear Models

    DOE PAGES

    Bernstein, Andrey; Wang, Cong; Dall'Anese, Emiliano; ...

    2018-01-01

    This paper considers unbalanced multiphase distribution systems with generic topology and different load models, and extends the Z-bus iterative load-flow algorithm based on a fixed-point interpretation of the AC load-flow equations. Explicit conditions for existence and uniqueness of load-flow solutions are presented. These conditions also guarantee convergence of the load-flow algorithm to the unique solution. The proposed methodology is applicable to generic systems featuring (i) wye connections; (ii) ungrounded delta connections; (iii) a combination of wye-connected and delta-connected sources/loads; and, (iv) a combination of line-to-line and line-to-grounded-neutral devices at the secondary of distribution transformers. Further, a sufficient condition for themore » non-singularity of the load-flow Jacobian is proposed. Finally, linear load-flow models are derived, and their approximation accuracy is analyzed. Theoretical results are corroborated through experiments on IEEE test feeders.« less

  16. Load-Flow in Multiphase Distribution Networks: Existence, Uniqueness, Non-Singularity, and Linear Models

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

    Bernstein, Andrey; Wang, Cong; Dall'Anese, Emiliano

    This paper considers unbalanced multiphase distribution systems with generic topology and different load models, and extends the Z-bus iterative load-flow algorithm based on a fixed-point interpretation of the AC load-flow equations. Explicit conditions for existence and uniqueness of load-flow solutions are presented. These conditions also guarantee convergence of the load-flow algorithm to the unique solution. The proposed methodology is applicable to generic systems featuring (i) wye connections; (ii) ungrounded delta connections; (iii) a combination of wye-connected and delta-connected sources/loads; and, (iv) a combination of line-to-line and line-to-grounded-neutral devices at the secondary of distribution transformers. Further, a sufficient condition for themore » non-singularity of the load-flow Jacobian is proposed. Finally, linear load-flow models are derived, and their approximation accuracy is analyzed. Theoretical results are corroborated through experiments on IEEE test feeders.« less

  17. Early Observations with the ACS Ramp Filters

    NASA Astrophysics Data System (ADS)

    Tsvetanov, Z.; Hartig, G.; Bohlin, R.; Tran, H. D.; Martel, A.; Sirianni, M.; Clampin, M.

    2002-05-01

    The Advanced Camera for Surveys (ACS) on-board the Hubble Space Telescope (HST) is equipped with a set of ramp filters which provide imaging capability at 2% and 9% bandwidth in the range 3700-10700 Å. Each ramp filter consist of three segments where the middle segment can be used with both the Wide Field Channel (WFC) and High Resolution Channel (HRC), while the inner and outer segments can be used only with WFC. The monochromatic field of view is approximately 40'' by 80''. We will present observations of the planetary nebula (PN) NGC6543 (the Cat's Eye) taken with the ACS ramp filetrs in several key emission lines - [O II] 3727, [O III] 5007, H-alpha+[N II], and [S II] 6725. These four emission lines fall onto three separate middle ramp segments - FR388N, FR505N, and FR656N - and will allow inter-comparison between the ACS ramp filters and fixed bandpass narrow-band filters F502N and F658N for both the WFC and HRC detectors. These observations were taken as part of the HST Servicing Mission Orbital Verification program and were designed to test ramp filters performance. We will demostrate our ability to obtain monochromatic (i.e., emission line) images at arbitrary wavelength and recover the surface brightness distribution. This work was supported by a NASA contract and a NASA grant.

  18. National Fuel Cell Bus Program: Accelerated Testing Evaluation Report and Appendices, Alameda-Contra Costa Transit District (AC Transit)

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

    Chandler, K.; Eudy, L.

    2009-01-01

    This is an evaluation of hydrogen fuel cell transit buses operating at AC Transit in revenue service since March 20, 2006 compared to similar diesel buses operating from the same depot. This evaluation report includes results from November 2007 through October 2008. Evaluation results include implementation experience, fueling station operation, fuel cell bus operations at Golden Gate Transit, and evaluation results at AC Transit (bus usage, availability, fuel economy, maintenance costs, and roadcalls).

  19. The additional benefit of the ML Flow test to classify leprosy patients.

    PubMed

    Bührer-Sékula, Samira; Illarramendi, Ximena; Teles, Rose B; Penna, Maria Lucia F; Nery, José Augusto C; Sales, Anna Maria; Oskam, Linda; Sampaio, Elizabeth P; Sarno, Euzenir N

    2009-08-01

    The use of the skin lesion counting classification leads to both under and over diagnosis of leprosy in many instances. Thus, there is a need to complement this classification with another simple and robust test for use in the field. Data of 202 untreated leprosy patients diagnosed at FIOCRUZ, Rio de Janeiro, Brazil, was analyzed. There were 90 patients classified as PB and 112 classified as MB according to the reference standard. The BI was positive in 111 (55%) patients and the ML Flow test in 116 (57.4%) patients. The ML Flow test was positive in 95 (86%) of the patients with a positive BI. The lesion counting classification was confirmed by both BI and ML Flow tests in 65% of the 92 patients with 5 or fewer lesions, and in 76% of the 110 patients with 6 or more lesions. The combination of skin lesion counting and the ML Flow test results yielded a sensitivity of 85% and a specificity of 87% for MB classification, and correctly classified 86% of the patients when compared to the standard reference. A considerable proportion of the patients (43.5%) with discordant test results in relation to standard classification was in reaction. The use of any classification system has limitations, especially those that oversimplify a complex disease such as leprosy. In the absence of an experienced dermatologist and slit skin smear, the ML Flow test could be used to improve treatment decisions in field conditions.

  20. Phase 2: HGM air flow tests in support of HEX vane investigation

    NASA Technical Reports Server (NTRS)

    Cox, G. B., Jr.; Steele, L. L.; Eisenhart, D. W.

    1993-01-01

    Following the start of SSME certification testing for the Pratt and Whitney Alternate Turbopump Development (ATD) High Pressure Oxidizer Turbopump (HPOTP), cracking of the leading edge of the inner HEX vane was experienced. The HEX vane, at the inlet of the oxidizer bowl in the Hot Gas Manifold (HGM), accepts the HPOTP turbine discharge flow and turns it toward the Gaseous Oxidizer Heat Exchanger (GOX HEX) coil. The cracking consistently initiated over a specific circumferential region of the hex vane, with other circumferential locations appearing with increased run time. Since cracking had not to date been seen with the baseline HPOTP, a fluid-structural interaction involving the ATD HPOTP turbine exit flowfield and the HEX inner vane was suspected. As part of NASA contract NAS8-36801, Pratt and Whitney conducted air flow tests of the ATD HPOTP turbine turnaround duct flowpath in the MSFC Phase 2 HGM air flow model. These tests included HEX vane strain gages and additional fluctuating pressure gages in the turnaround duct and HEX vane flowpath area. Three-dimensional flow probe measurements at two stations downstream of the turbine simulator exit plane were also made. Modifications to the HPOTP turbine simulator investigated the effects on turbine exit flow profile and velocity components, with the objective of reproducing flow conditions calculated for the actual ATD HPOTP hardware. Testing was done at the MSFC SSME Dynamic Fluid Air Flow (Dual-Leg) Facility, at air supply pressures between 50 and 250 psia. Combinations of turbine exit Mach number and pressure level were run to investigate the effect of flow regime. Information presented includes: (1) Descriptions of turbine simulator modifications to produce the desired flow environment; (2) Types and locations for instrumentation added to the flow model for improved diagnostic capability; (3) Evaluation of the effect of changes to the turbine simulator flowpath on the turbine exit flow environment; and (4

  1. High-Frequency ac Power-Distribution System

    NASA Technical Reports Server (NTRS)

    Hansen, Irving G.; Mildice, James

    1987-01-01

    Loads managed automatically under cycle-by-cycle control. 440-V rms, 20-kHz ac power system developed. System flexible, versatile, and "transparent" to user equipment, while maintaining high efficiency and low weight. Electrical source, from dc to 2,200-Hz ac converted to 440-V rms, 20-kHz, single-phase ac. Power distributed through low-inductance cables. Output power either dc or variable ac. Energy transferred per cycle reduced by factor of 50. Number of parts reduced by factor of about 5 and power loss reduced by two-thirds. Factors result in increased reliability and reduced costs. Used in any power-distribution system requiring high efficiency, high reliability, low weight, and flexibility to handle variety of sources and loads.

  2. Scalable Heuristics for Planning, Placement and Sizing of Flexible AC Transmission System Devices

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

    Frolov, Vladmir; Backhaus, Scott N.; Chertkov, Michael

    Aiming to relieve transmission grid congestion and improve or extend feasibility domain of the operations, we build optimization heuristics, generalizing standard AC Optimal Power Flow (OPF), for placement and sizing of Flexible Alternating Current Transmission System (FACTS) devices of the Series Compensation (SC) and Static VAR Compensation (SVC) type. One use of these devices is in resolving the case when the AC OPF solution does not exist because of congestion. Another application is developing a long-term investment strategy for placement and sizing of the SC and SVC devices to reduce operational cost and improve power system operation. SC and SVCmore » devices are represented by modification of the transmission line inductances and reactive power nodal corrections respectively. We find one placement and sizing of FACTs devices for multiple scenarios and optimal settings for each scenario simultaneously. Our solution of the nonlinear and nonconvex generalized AC-OPF consists of building a convergent sequence of convex optimizations containing only linear constraints and shows good computational scaling to larger systems. The approach is illustrated on single- and multi-scenario examples of the Matpower case-30 model.« less

  3. 78 FR 39345 - ACS Wireless, Inc.; Notice of Application

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-07-01

    ... on July 31, 1995 under the name MACTEL INC. Alaska Communications Systems Group, Inc. (``ACS Group...-owned subsidiary of ACS Group, held through ACS Group's wholly-owned subsidiary Alaska Communications... presently an investment company as defined in section 3(a) of the Act. 2. On June 4, 2012, ACS Group, ACS...

  4. Tests of the accuracy and speed of categorizing foods into child vs. professional categories using two methods of browsing with children.

    USDA-ARS?s Scientific Manuscript database

    This research tested whether children could categorize foods more accurately and speedily when presented with child-generated rather than professionally-generated food categories; and whether a graphically appealing browse procedure similar to the Apple, Inc, "cover flow" graphical user interface ac...

  5. Curved-flow, rolling-flow, and oscillatory pure-yawing wind-tunnel test methods for determination of dynamic stability derivatives

    NASA Technical Reports Server (NTRS)

    Chambers, J. R.; Grafton, S. B.; Lutze, F. H.

    1981-01-01

    The test capabilities of the Stability Wind Tunnel of the Virginia Polytechnic Institute and State University are described, and calibrations for curved and rolling flow techniques are given. Oscillatory snaking tests to determine pure yawing derivatives are considered. Representative aerodynamic data obtained for a current fighter configuration using the curved and rolling flow techniques are presented. The application of dynamic derivatives obtained in such tests to the analysis of airplane motions in general, and to high angle of attack flight conditions in particular, is discussed.

  6. Changes in stimulus and response AC/A ratio with vision therapy in Convergence Insufficiency.

    PubMed

    Singh, Neeraj Kumar; Mani, Revathy; Hussaindeen, Jameel Rizwana

    To evaluate the changes in the stimulus and response Accommodative Convergence to Accommodation (AC/A) ratio following vision therapy (VT) in Convergence Insufficiency (CI). Stimulus and response AC/A ratio were measured on twenty five CI participants, pre and post 10 sessions of VT. Stimulus AC/A ratio was measured using the gradient method and response AC/A ratio was calculated using modified Thorington technique with accommodative responses measured using WAM-5500 open-field autorefractor. The gradient stimulus and response AC/A cross-link ratios were compared with thirty age matched controls. Mean age of the CI and control participants were 23.3±5.2 years and 22.7±4.2 years, respectively. The mean stimulus and response AC/A ratio for CI pre therapy was 2.2±0.72 and 6.3±2.0 PD/D that changed to 4.2±0.9 and 8.28±3.31 PD/D respectively post vision therapy and these changes were statistically significant (paired t-test; p<0.001). The mean stimulus and response AC/A ratio for controls was 3.1±0.81 and 8.95±2.5 PD/D respectively. Stimulus and response AC/A ratio increased following VT, accompanied by clinically significant changes in vergence and accommodation parameters in subjects with convergence insufficiency. This represents the plasticity of the AC/A crosslink ratios that could be achieved with vision therapy in CI. Copyright © 2016 Spanish General Council of Optometry. Published by Elsevier España, S.L.U. All rights reserved.

  7. Final Report for the Advanced Camera for Surveys (ACS)

    NASA Technical Reports Server (NTRS)

    2004-01-01

    ACS was launched aboard the Space Shuttle Columbia just before dawn on March 1, 2002. At the time of liftoff, the Hubble Space Telescope (HST) was reflecting the early morning sun as it moved across the sky. After successfully docking with HST, several components were replaced. One of the components was the Advanced Camera for Surveys built by Ball Aerospace & Technologies Corp. (BATC) in Boulder, Colorado. Over the life of the HST contract at BATC, hundreds of employees had the pleasure of working on the concept, design, fabrication, assembly, and test of ACS. Those employees thank NASA - Goddard Space Flight Center and the science team at Johns Hopkins University (JHU) for the opportunity to participate in building a great science instrument for HST.

  8. Results from the Water Flow Test of the Tank 37 Backflush Valve

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

    Fowley, M.D.

    2002-11-01

    A flow test was conducted in the Thermal Fluids Lab with the Tank 37 Backflush Valve to determine the pressure drop of water flow through the material transfer port. The flow rate was varied from 0 to 100 gpm. The pressure drop through the Backflush Valve for flow rates of 20 and 70 gpm was determined to be 0.18 and 1.77 feet of H2O, respectively. An equivalent length of the Backflush Valve was derived from the flow test data. The equivalent length was used in a head loss calculation for the Tank 37 Gravity Drain Line. The calculation estimated themore » flow rate that would fill the line up to the Separator Tank, and the additional flow rate that would fill the Separator Tank. The viscosity of the fluid used in the calculation was 12 centipoise. Two specific gravities were investigated, 1.4 and 1.8. The Gravity Drain Line was assumed to be clean, unobstructed stainless steel pipe. The flow rate that would fill the line up to the Separator Tank was 73 and 75 gpm for the 1.4 or 1.8 specific gravity fluids, respectively. The flow rate that would fill the Separator Tank was 96 and 100 gpm for the 1.4 or 1.8 specific gravity fluids, respectively. These results indicate that concentrate will not back up into the Separator Tank during evaporator normal operation, 15-25 gpm, or pot liftout, 70 gpm. A noteworthy observation during the flow test was water pouring from the holes in the catheterization tube. Water poured from the holes at 25 gpm and above. Data from the water flow test indicates that at 25 gpm the pressure drop through the Backflush Valve is 0.26 ft of H2O. A concentrate with a specific gravity of 1.8 and a viscosity of 12 cp will produce the same pressure drop at 20 gpm. This implies that concentrate from the evaporator may spill out into the BFV riser during a transfer.« less

  9. Flow and Reading Comprehension: Testing the Mediating Role of Emotioncy

    ERIC Educational Resources Information Center

    Shahian, Leila; Pishghadam, Reza; Khajavy, Gholam Hassan

    2017-01-01

    Considering the importance of psychological factors in learners' reading abilities, this study examines the relationship between flow, emotioncy, and reading comprehension. To this end, 238 upper-intermediate and advanced English as a Foreign Language (EFL) learners were asked to take four tests of reading comprehension along with flow and…

  10. Characterization of AC current sensor based on giant magnetoresistance and coil for power meter design

    NASA Astrophysics Data System (ADS)

    Dhani, H. S.; Aminudin, A.; Waslaluddin

    2018-05-01

    Electric current is the basic variable of measurement in instrumentation system. One of the current measurements had been developed was based on magnetic sensor. Giant Magnetoresistance (GMR) produces an output voltage when it detects the magnetic field from electric current flow. The purpose of this study was to characterize the response of GMR when variation number of coil was given. The characterization was the GMR voltage response to the AC current values from 0.01 A to 5.00 A. The linearity of the relation was reaching saturation point when the magnetic field measured higher than 10.5 Oe at room temperature. As the number of coil increased, the earlier saturation occurred. To see the sensitivity of the sensor response, the data graph was cut off at 1.56 A AC. From this research, we got single coil was ideal to measure electric current higher than 1.56 A AC, as the relation of GMR voltage to the current tended to maintain its linearity. For measurement of 1.56 A AC and less, coil number addition would increase the sensitivity of sensor response. This research hopefully will be benefit for further development using an electric current measurement based on GMR magnetic sensor for power meter design.

  11. A new methodology for hydro-abrasive erosion tests simulating penstock erosive flow

    NASA Astrophysics Data System (ADS)

    Aumelas, V.; Maj, G.; Le Calvé, P.; Smith, M.; Gambiez, B.; Mourrat, X.

    2016-11-01

    Hydro-abrasive resistance is an important property requirement for hydroelectric power plant penstock coating systems used by EDF. The selection of durable coating systems requires an experimental characterization of coating performance. This can be achieved by performing accelerated and representative laboratory tests. In case of severe erosion induced by a penstock flow, there is no suitable method or standard representative of real erosive flow conditions. The presented study aims at developing a new methodology and an associated laboratory experimental device. The objective of the laboratory apparatus is to subject coated test specimens to wear conditions similar to the ones generated at the penstock lower generatrix in actual flow conditions. Thirteen preselected coating solutions were first been tested during a 45 hours erosion test. A ranking of the thirteen coating solutions was then determined after characterisation. To complete this first evaluation and to determine the wear kinetic of the four best coating solutions, additional erosion tests were conducted with a longer duration of 216 hours. A comparison of this new method with standardized tests and with real service operating flow conditions is also discussed. To complete the final ranking based on hydro-abrasive erosion tests, some trial tests were carried out on penstock samples to check the application method of selected coating systems. The paper gives some perspectives related to erosion test methodologies for materials and coating solutions for hydraulic applications. The developed test method can also be applied in other fields.

  12. AC conductivity and dielectric behavior of bulk Furfurylidenemalononitrile

    NASA Astrophysics Data System (ADS)

    El-Nahass, M. M.; Ali, H. A. M.

    2012-06-01

    AC conductivity and dielectric behavior for bulk Furfurylidenemalononitrile have been studied over a temperature range (293-333 K) and frequency range (50-5×106 Hz). The frequency dependence of ac conductivity, σac, has been investigated by the universal power law, σac(ω)=Aωs. The variation of the frequency exponent (s) with temperature was analyzed in terms of different conduction mechanisms, and it was found that the correlated barrier hopping (CBH) model is the predominant conduction mechanism. The temperature dependence of σac(ω) showed a linear increase with the increase in temperature at different frequencies. The ac activation energy was determined at different frequencies. Dielectric data were analyzed using complex permittivity and complex electric modulus for bulk Furfurylidenemalononitrile at various temperatures.

  13. Linear optics measurements and corrections using an AC dipole in RHIC

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

    Wang, G.; Bai, M.; Yang, L.

    2010-05-23

    We report recent experimental results on linear optics measurements and corrections using ac dipole. In RHIC 2009 run, the concept of the SVD correction algorithm is tested at injection energy for both identifying the artificial gradient errors and correcting it using the trim quadrupoles. The measured phase beatings were reduced by 30% and 40% respectively for two dedicated experiments. In RHIC 2010 run, ac dipole is used to measure {beta}* and chromatic {beta} function. For the 0.65m {beta}* lattice, we observed a factor of 3 discrepancy between model and measured chromatic {beta} function in the yellow ring.

  14. Rapid susceptibility testing of fungi by flow cytometry using vital staining.

    PubMed Central

    Wenisch, C; Linnau, K F; Parschalk, B; Zedtwitz-Liebenstein, K; Georgopoulos, A

    1997-01-01

    A 1-h assay for antifungal susceptibility testing measuring the impairment of fungal metabolic activity was developed. Yeast viability was analyzed by flow cytometry with a novel fluorescent probe, FUN-1, which emits a red fluorescence when the yeast is metabolically active. For nine Candida albicans strains tested, this method yielded results comparable to those obtained by the standard M27 procedure for amphotericin B, flucytosine, fluconazole, and ketoconazole. Whether the flow cytometry antifungal susceptibility test results correlate with the in vivo activities of the drugs remains to determined. PMID:8968873

  15. Space Launch System Base Heating Test: Environments and Base Flow Physics

    NASA Technical Reports Server (NTRS)

    Mehta, Manish; Knox, Kyle; Seaford, Mark; Dufrene, Aaron

    2016-01-01

    NASA MSFC and CUBRC designed and developed a 2% scale SLS propulsive wind tunnel test program to investigate base flow effects during flight from lift-off to MECO. This type of test program has not been conducted in 40+ years during the NASA Shuttle Program. Dufrene et al paper described the operation, instrumentation type and layout, facility and propulsion performance, test matrix and conditions and some raw results. This paper will focus on the SLS base flow physics and the generation and results of the design environments being used to design the thermal protection system.

  16. Assay Methods for ACS Activity and ACS Phosphorylation by MAP Kinases In Vitro and In Vivo.

    PubMed

    Han, Xiaomin; Li, Guojing; Zhang, Shuqun

    2017-01-01

    Ethylene, a gaseous phytohormone, has profound effects on plant growth, development, and adaptation to the environment. Ethylene-regulated processes begin with the induction of ethylene biosynthesis. There are two key steps in ethylene biosynthesis. The first is the biosynthesis of 1-aminocyclopropane-1-carboxylic acid (ACC) from S-Adenosyl-Methionine (SAM), a common precursor in many metabolic pathways, which is catalyzed by ACC synthase (ACS). The second is the oxidative cleavage of ACC to form ethylene under the action of ACC oxidase (ACO). ACC biosynthesis is the committing and generally the rate-limiting step in ethylene biosynthesis. As a result, characterizing the cellular ACS activity and understanding its regulation are important. In this chapter, we detail the methods used to measure, (1) the enzymatic activity of both recombinant and native ACS proteins, and (2) the phosphorylation of ACS protein by mitogen-activated protein kinases (MAPKs) in vivo and in vitro.

  17. Method of driving liquid flow at or near the free surface using magnetic microparticles

    DOEpatents

    Snezhko, Oleksiy [Woodridge, IL; Aronson, Igor [Darien, IL; Kwok, Wai-Kwong [Evanston, IL; Belkin, Maxim V [Woodridge, IL

    2011-10-11

    The present invention provides a method of driving liquid flow at or near a free surface using self-assembled structures composed of magnetic particles subjected to an external AC magnetic field. A plurality of magnetic particles are supported at or near a free surface of liquid by surface tension or buoyancy force. An AC magnetic field traverses the free surface and dipole-dipole interaction between particles produces in self-assembled snake structures which oscillate at the frequency of the traverse AC magnetic field. The snake structures independently move across the free surface and may merge with other snake structures or break up and coalesce into additional snake structures experiencing independent movement across the liquid surface. During this process, the snake structures produce asymmetric flow vortices across substantially the entirety of the free surface, effectuating liquid flow across the free surface.

  18. Compound Capillary Flows in Complex Containers: Drop Tower Test Results

    NASA Astrophysics Data System (ADS)

    Bolleddula, Daniel A.; Chen, Yongkang; Semerjian, Ben; Tavan, Noël; Weislogel, Mark M.

    2010-10-01

    Drop towers continue to provide unique capabilities to investigate capillary flow phenomena relevant to terrestrial and space-based capillary fluidics applications. In this study certain `capillary rise' flows and the value of drop tower experimental investigations are briefly reviewed. A new analytic solution for flows along planar interior edges is presented. A selection of test cell geometries are then discussed where compound capillary flows occur spontaneously and simultaneously over local and global length scales. Sample experimental results are provided. Tertiary experiments on a family of asymmetric geometries that isolate the global component of such flows are then presented along with a qualitative analysis that may be used to either avoid or exploit such flows. The latter may also serve as a design tool with which to assess the impact of inadvertent container asymmetry.

  19. Measuring flow velocity and flow direction by spatial and temporal analysis of flow fluctuations.

    PubMed

    Chagnaud, Boris P; Brücker, Christoph; Hofmann, Michael H; Bleckmann, Horst

    2008-04-23

    If exposed to bulk water flow, fish lateral line afferents respond only to flow fluctuations (AC) and not to the steady (DC) component of the flow. Consequently, a single lateral line afferent can encode neither bulk flow direction nor velocity. It is possible, however, for a fish to obtain bulk flow information using multiple afferents that respond only to flow fluctuations. We show by means of particle image velocimetry that, if a flow contains fluctuations, these fluctuations propagate with the flow. A cross-correlation of water motion measured at an upstream point with that at a downstream point can then provide information about flow velocity and flow direction. In this study, we recorded from pairs of primary lateral line afferents while a fish was exposed to either bulk water flow, or to the water motion caused by a moving object. We confirm that lateral line afferents responded to the flow fluctuations and not to the DC component of the flow, and that responses of many fiber pairs were highly correlated, if they were time-shifted to correct for gross flow velocity and gross flow direction. To prove that a cross-correlation mechanism can be used to retrieve the information about gross flow velocity and direction, we measured the flow-induced bending motions of two flexible micropillars separated in a downstream direction. A cross-correlation of the bending motions of these micropillars did indeed produce an accurate estimate of the velocity vector along the direction of the micropillars.

  20. ARC-1964-AC-33500-2

    NASA Image and Video Library

    1964-10-01

    DURING APPROACH. OGEE Wing Planform on modified F5D-1 SkylancerAirplane Flight Tests. 'Flow Visualization Photographs'. In landing approach trials at Moffett Field, vapor trails are generated by low pressure in votex flow near wing leading edge on upper wing surface. Studies were undertaken in efforts to determine if there were adverse effects of vortex flow on the dynamic stability of the aircraft.

  1. Fan Noise Source Diagnostic Test: LDV Measured Flow Field Results

    NASA Technical Reports Server (NTRS)

    Podboy, Gary C.; Krupar, Martin J.; Hughes, Christopher E.; Woodward, Richard P.

    2003-01-01

    Results are presented of an experiment conducted to investigate potential sources of noise in the flow developed by two 22-in. diameter turbofan models. The R4 and M5 rotors that were tested were designed to operate at nominal take-off speeds of 12,657 and 14,064 RPMC, respectively. Both fans were tested with a common set of swept stators installed downstream of the rotors. Detailed measurements of the flows generated by the two were made using a laser Doppler velocimeter system. The wake flows generated by the two rotors are illustrated through a series of contour plots. These show that the two wake flows are quite different, especially in the tip region. These data are used to explain some of the differences in the rotor/stator interaction noise generated by the two fan stages. In addition to these wake data, measurements were also made in the R4 rotor blade passages. These results illustrate the tip flow development within the blade passages, its migration downstream, and (at high rotor speeds) its merging with the blade wake of the adjacent (following) blade. Data also depict the variation of this tip flow with tip clearance. Data obtained within the rotor blade passages at high rotational speeds illustrate the variation of the mean shock position across the different blade passages.

  2. The influence of changes in blood flow on the accuracy of pulse oximetry in humans.

    PubMed

    Vegfors, M; Lindberg, L G; Lennmarken, C

    1992-05-01

    Oxygen saturation (SpO2) was measured with a pulse oximeter in ten healthy, young men breathing air. A pulse oximeter probe was attached to the second toe and a laser Doppler probe to the first toe of the same foot for measurement of changes in peripheral blood flow. The pulse oximeter and laser Doppler readings were simultaneously compared when the foot was positioned 40 cm (position 1) above heart level, elevated 10 cm (position 2) above heart level and horizontally at heart level (position 3). Using this experimental human model, we achieved various blood flows. The AC and DC optical signals used for determination of oxygen saturation were recorded from the pulse oximeter and analysed. There was a significant increase (P less than 0.05) between position 1 and 3 in blood flow as measured by the laser Doppler flow meter. The corresponding pulse oximeter readings of haemoglobin saturation also increased significantly (P less than 0.05) comparing these two leg positions. Analysing the AC- and DC optical signals, the AC value of infrared light increased considerably, while the AC value of the red light decreased slightly. The DC values of red and infrared light did not change significantly. In summary, when blood flow was decreased, the ratio of red to infrared transmitted light was changed, resulting in a low SpO2 reading.

  3. Gamma-irradiation produces active chlorine species (ACS) in physiological solutions: Secoisolariciresinol diglucoside (SDG) scavenges ACS - A novel mechanism of DNA radioprotection

    PubMed Central

    Mishra, Om P.; Popov, Anatoliy V.; Pietrofesa, Ralph A.; Christofidou-Solomidou, Melpo

    2017-01-01

    Background Secoisolariciresinol diglucoside (SDG), the main lignan in whole grain flaxseed, is a potent antioxidant and free radical scavenger with known radioprotective properties. However, the exact mechanism of SDG radioprotection is not well understood. The current study identified a novel mechanism of DNA radioprotection by SDG in physiological solutions by scavenging active chlorine species (ACS) and reducing chlorinated nucleobases. Methods The ACS scavenging activity of SDG was determined using two highly specific fluoroprobes: hypochlorite-specific 3′-(p-aminophenyl) fluorescein (APF) and hydroxyl radical-sensitive 3′-(p-hydroxyphenyl) fluorescein (HPF). Dopamine, an SDG structural analog, was used for proton 1H NMR studies to trap primary ACS radicals. Taurine N-chlorination was determined to demonstrate radiation-induced generation of hypochlorite, a secondary ACS. DNA protection was assessed by determining the extent of DNA fragmentation and plasmid DNA relaxation following exposure to ClO− and radiation. Purine base chlorination by ClO− and γ-radiation was determined by using 2-aminopurine (2-AP), a fluorescent analog of 6-aminopurine. Results: Chloride anions (Cl−) consumed >90% of hydroxyl radicals in physiological solutions produced by γ-radiation resulting in ACS formation, which was detected by 1H NMR. Importantly, SDG scavenged hypochlorite- and γ-radiation-induced ACS. In addition, SDG blunted ACS-induced fragmentation of calf thymus DNA and plasmid DNA relaxation. SDG treatment before or after ACS exposure decreased the ClO− or γ-radiation-induced chlorination of 2-AP. Exposure to γ-radiation resulted in increased taurine chlorination, indicative of ClO− generation. NMR studies revealed formation of primary ACS radicals (chlorine atoms (Cl•) and dichloro radical anions (Cl2−•)), which were trapped by SDG and its structural analog dopamine. Conclusion We demonstrate that γ-radiation induces the generation of ACS in

  4. Gamma-irradiation produces active chlorine species (ACS) in physiological solutions: Secoisolariciresinol diglucoside (SDG) scavenges ACS - A novel mechanism of DNA radioprotection.

    PubMed

    Mishra, Om P; Popov, Anatoliy V; Pietrofesa, Ralph A; Christofidou-Solomidou, Melpo

    2016-09-01

    Secoisolariciresinol diglucoside (SDG), the main lignan in whole grain flaxseed, is a potent antioxidant and free radical scavenger with known radioprotective properties. However, the exact mechanism of SDG radioprotection is not well understood. The current study identified a novel mechanism of DNA radioprotection by SDG in physiological solutions by scavenging active chlorine species (ACS) and reducing chlorinated nucleobases. The ACS scavenging activity of SDG was determined using two highly specific fluoroprobes: hypochlorite-specific 3'-(p-aminophenyl) fluorescein (APF) and hydroxyl radical-sensitive 3'-(p-hydroxyphenyl) fluorescein (HPF). Dopamine, an SDG structural analog, was used for proton (1)H NMR studies to trap primary ACS radicals. Taurine N-chlorination was determined to demonstrate radiation-induced generation of hypochlorite, a secondary ACS. DNA protection was assessed by determining the extent of DNA fragmentation and plasmid DNA relaxation following exposure to ClO(-) and radiation. Purine base chlorination by ClO(-) and γ-radiation was determined by using 2-aminopurine (2-AP), a fluorescent analog of 6-aminopurine. Chloride anions (Cl(-)) consumed >90% of hydroxyl radicals in physiological solutions produced by γ-radiation resulting in ACS formation, which was detected by (1)H NMR. Importantly, SDG scavenged hypochlorite- and γ-radiation-induced ACS. In addition, SDG blunted ACS-induced fragmentation of calf thymus DNA and plasmid DNA relaxation. SDG treatment before or after ACS exposure decreased the ClO(-) or γ-radiation-induced chlorination of 2-AP. Exposure to γ-radiation resulted in increased taurine chlorination, indicative of ClO(-) generation. NMR studies revealed formation of primary ACS radicals (chlorine atoms (Cl) and dichloro radical anions (Cl2¯)), which were trapped by SDG and its structural analog dopamine. We demonstrate that γ-radiation induces the generation of ACS in physiological solutions. SDG treatment scavenged

  5. National Fuel Cell Bus Program: Accelerated Testing Evaluation Report #2, Alameda-Contra Costa Transit District (AC Transit) and Appendices

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

    Eudy, L.; Chandler, K.

    2010-06-01

    This is an evaluation of hydrogen fuel cell transit buses operating at AC Transit in revenue service since March 20, 2006, comparing similar diesel buses operating from the same depot. It covers November 2007 through February 2010. Results include implementation experience, fueling station operation, evaluation results at AC Transit (bus usage, availability, fuel economy, maintenance costs, and road calls), and a summary of achievements and challenges encountered during the demonstration.

  6. Superconductor coil geometry and ac losses

    NASA Technical Reports Server (NTRS)

    Pierce, T. V., Jr.; Zapata, R. N.

    1976-01-01

    An empirical relation is presented which allows simple computation of volume-averaged winding fields from central fields for coils of small rectangular cross sections. This relation suggests that, in certain applications, ac-loss minimization can be accomplished by use of low winding densities, provided that hysteresis losses are independent of winding density. The ac-loss measurements on coils wound of twisted multifilamentary composite superconductors show no significant dependence on ac losses on winding density, thus permitting the use of winding density as an independent design parameter in loss minimization.

  7. Towards high concentration enhancement of microfluidic temperature gradient focusing of sample solutes using combined AC and DC field induced Joule heating.

    PubMed

    Ge, Zhengwei; Wang, Wei; Yang, Chun

    2011-04-07

    It is challenging to continuously concentrate sample solutes in microfluidic channels. We present an improved electrokinetic technique for enhancing microfluidic temperature gradient focusing (TGF) of sample solutes using combined AC and DC field induced Joule heating effects. The introduction of an AC electric field component services dual functions: one is to produce Joule heat for generating temperature gradient; the other is to suppress electroosmotic flow. Consequently the required DC voltages for achieving sample concentration by Joule heating induced TGF are reduced, thereby leading to smaller electroosmotic flow (EOF) and thus backpressure effects. As a demonstration, the proposed technique can lead to concentration enhancement of sample solutes of more than 2500-fold, which is much higher than the existing literature reported microfluidic concentration enhancement by utilizing the Joule heating induced TGF technique.

  8. Effect of oxidation of carbon material on suspension electrodes for flow electrode capacitive deionization.

    PubMed

    Hatzell, Kelsey B; Hatzell, Marta C; Cook, Kevin M; Boota, Muhammad; Housel, Gabrielle M; McBride, Alexander; Kumbur, E Caglan; Gogotsi, Yury

    2015-03-03

    Flow electrode deionization (FCDI) is an emerging area for continuous and scalable deionization, but the electrochemical and flow properties of the flow electrode need to be improved to minimize energy consumption. Chemical oxidation of granular activated carbon (AC) was examined here to study the role of surface heteroatoms on rheology and electrochemical performance of a flow electrode (carbon slurry) for deionization processes. Moreover, it was demonstrated that higher mass densities could be used without increasing energy for pumping when using oxidized active material. High mass-loaded flow electrodes (28% carbon content) based on oxidized AC displayed similar viscosities (∼21 Pa s) to lower mass-loaded flow electrodes (20% carbon content) based on nonoxidized AC. The 40% increased mass loading (from 20% to 28%) resulted in a 25% increase in flow electrode gravimetric capacitance (from 65 to 83 F g(-1)) without sacrificing flowability (viscosity). The electrical energy required to remove ∼18% of the ions (desalt) from of the feed solution was observed to be significantly dependent on the mass loading and decreased (∼60%) from 92 ± 7 to 28 ± 2.7 J with increased mass densities from 5 to 23 wt %. It is shown that the surface chemistry of the active material in a flow electrode effects the electrical and pumping energy requirements of a FCDI system.

  9. Effect of oxidation of carbon material on suspension electrodes for flow electrode capacitive deionization

    DOE PAGES

    Hatzell, Kelsey B.; Hatzell, Marta C.; Cook, Kevin M.; ...

    2015-01-29

    Flow electrode deionization (FCDI) is an emerging area for continuous and scalable deionization, but the electrochemical and flow properties of the flow electrode need to be improved to minimize energy consumption. We examine chemical oxidation of granular activated carbon (AC) here to study the role of surface heteroatoms on rheology and electrochemical performance of a flow electrode (carbon slurry) for deionization processes. Moreover, it was demonstrated that higher mass densities could be used without increasing energy for pumping when using oxidized active material. High mass-loaded flow electrodes (28% carbon content) based on oxidized AC displayed similar viscosities (~21 Pa s)more » to lower mass-loaded flow electrodes (20% carbon content) based on nonoxidized AC. The 40% increased mass loading (from 20% to 28%) resulted in a 25% increase in flow electrode gravimetric capacitance (from 65 to 83 F g –1) without sacrificing flowability (viscosity). The electrical energy required to remove ~18% of the ions (desalt) from of the feed solution was observed to be significantly dependent on the mass loading and decreased (~60%) from 92 ± 7 to 28 ± 2.7 J with increased mass densities from 5 to 23 wt %. Finally, it is shown that the surface chemistry of the active material in a flow electrode effects the electrical and pumping energy requirements of a FCDI system.« less

  10. Magnetic Amplifier-Based Power-Flow Controller

    DOE PAGES

    Dimitrovski, Aleksandar; Li, Zhi; Ozpineci, Burak

    2015-02-05

    The concept of the magnetic amplifier, a common electromagnetic device in electronic applications in the past, has seldom been used in power systems. In this paper, we introduce the magnetic amplifier-based power-flow controller (MAPFC), an innovative low-cost device that adopts the idea of the magnetic amplifier for power-flow control applications. The uniqueness of MAPFC is in the use of the magnetization of the ferromagnetic core, shared by an ac and a dc winding, as the medium to control the ac winding reactance inserted in series with the transmission line to be controlled. Large power flow in the line can bemore » regulated by the small dc input to the dc winding. Moreover, a project on the R&D of an MAPFC has been funded by the U.S. Department of Energy (DOE) and conducted by the Oak Ridge National Laboratory (ORNL), the University of Tennessee-Knoxville, and Waukesha Electric Systems, Inc. since early 2012. Findings from the project are presented along with some results obtained in a laboratory environment.« less

  11. Effects from Unsaturated Zone Flow during Oscillatory Hydraulic Testing

    NASA Astrophysics Data System (ADS)

    Lim, D.; Zhou, Y.; Cardiff, M. A.; Barrash, W.

    2014-12-01

    In analyzing pumping tests on unconfined aquifers, the impact of the unsaturated zone is often neglected. Instead, desaturation at the water table is often treated as a free-surface boundary, which is simple and allows for relatively fast computation. Richards' equation models, which account for unsaturated flow, can be compared with saturated flow models to validate the use of Darcy's Law. In this presentation, we examine the appropriateness of using fast linear steady-periodic models based on linearized water table conditions in order to simulate oscillatory pumping tests in phreatic aquifers. We compare oscillatory pumping test models including: 1) a 2-D radially-symmetric phreatic aquifer model with a partially penetrating well, simulated using both Darcy's Law and Richards' Equation in COMSOL; and 2) a linear phase-domain numerical model developed in MATLAB. Both COMSOL and MATLAB models are calibrated to match oscillatory pumping test data collected in the summer of 2013 at the Boise Hydrogeophysical Research Site (BHRS), and we examine the effect of model type on the associated parameter estimates. The results of this research will aid unconfined aquifer characterization efforts and help to constrain the impact of the simplifying physical assumptions often employed during test analysis.

  12. Analysis of volatiles in fire debris by combination of activated charcoal strips (ACS) and automated thermal desorption-gas chromatography-mass spectrometry (ATD/GC-MS).

    PubMed

    Martin Fabritius, Marie; Broillet, Alain; König, Stefan; Weinmann, Wolfgang

    2018-06-04

    Adsorption of volatiles in gaseous phase to activated charcoal strip (ACS) is one possibility for the extraction and concentration of ignitable liquid residues (ILRs) from fire debris in arson investigations. Besides liquid extraction using carbon dioxide or hexane, automated thermo-desorption can be used to transfer adsorbed residues to direct analysis by gas chromatography-mass spectrometry (GC-MS). We present a fire debris analysis work-flow with headspace adsorption of volatiles onto ACS and subsequent automated thermo-desorption (ATD) GC-MS analysis. Only a small portion of the ACS is inserted in the ATD tube for thermal desorption coupled to GC-MS, allowing for subsequent confirmation analysis with another portion of the same ACS. This approach is a promising alternative to the routinely used ACS method with solvent extraction of retained volatiles, and the application to fire debris analysis is demonstrated. Copyright © 2018 Elsevier B.V. All rights reserved.

  13. In-plane microvortices micromixer-based AC electrothermal for testing drug induced death of tumor cells.

    PubMed

    Lang, Qi; Ren, Yukun; Hobson, Divia; Tao, Ye; Hou, Likai; Jia, Yankai; Hu, Qingming; Liu, Jiangwei; Zhao, Xin; Jiang, Hongyuan

    2016-11-01

    Herein, we first describe a perfusion chip integrated with an AC electrothermal (ACET) micromixer to supply a uniform drug concentration to tumor cells. The in-plane fluid microvortices for mixing were generated by six pairs of reconstructed novel ACET asymmetric electrodes. To enhance the mixing efficiency, the novel ACET electrodes with rotating angles of 0°, 30°, and 60° were investigated. The asymmetric electrodes with a rotating angle of 60° exhibited the highest mixing efficiency by both simulated and experimental results. The length of the mixing area is 7 mm, and the mixing efficiency is 89.12% (approximate complete mixing) at a voltage of 3 V and a frequency of 500 kHz. The applicability of our micromixer with electrodes rotating at 60° was demonstrated by the drug (tamoxifen) test of human breast cancer cells (MCF-7) for five days, which implies that our ACET in-plane microvortices micromixer has great potential for the application of drug induced rapid death of tumor cells and mixing of biomaterials in organs-on-a-chip systems.

  14. In-plane microvortices micromixer-based AC electrothermal for testing drug induced death of tumor cells

    PubMed Central

    Lang, Qi; Ren, Yukun; Tao, Ye; Hou, Likai; Jia, Yankai; Hu, Qingming; Liu, Jiangwei; Zhao, Xin; Jiang, Hongyuan

    2016-01-01

    Herein, we first describe a perfusion chip integrated with an AC electrothermal (ACET) micromixer to supply a uniform drug concentration to tumor cells. The in-plane fluid microvortices for mixing were generated by six pairs of reconstructed novel ACET asymmetric electrodes. To enhance the mixing efficiency, the novel ACET electrodes with rotating angles of 0°, 30°, and 60° were investigated. The asymmetric electrodes with a rotating angle of 60° exhibited the highest mixing efficiency by both simulated and experimental results. The length of the mixing area is 7 mm, and the mixing efficiency is 89.12% (approximate complete mixing) at a voltage of 3 V and a frequency of 500 kHz. The applicability of our micromixer with electrodes rotating at 60° was demonstrated by the drug (tamoxifen) test of human breast cancer cells (MCF-7) for five days, which implies that our ACET in-plane microvortices micromixer has great potential for the application of drug induced rapid death of tumor cells and mixing of biomaterials in organs-on-a-chip systems. PMID:27917250

  15. Laminar and Turbulent Flow Calculations for the Hifire-5B Flight Test

    DTIC Science & Technology

    2017-11-01

    STATES AIR FORCE AFRL-RQ-WP-TP-2017-0172 LAMINAR AND TURBULENT FLOW CALCULATIONS FOR THE HIFIRE-5B FLIGHT TEST Roger L. Kimmel Hypersonic Sciences...LAMINAR AND TURBULENT FLOW CALCULATIONS FOR THE HIFIRE-5B FLIGHT TEST 5a. CONTRACT NUMBER In-house 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER...Clearance Date: 28 Apr 2017 14. ABSTRACT The HIFiRE-5b program launched an experimental FLight test vehicle to study laminar-turbulent transition

  16. In Situ Local Fracture Flow Measurement by the Double Packer Dilution Test

    NASA Astrophysics Data System (ADS)

    Englert, A.; Le Borgne, T.; Bour, O.; Klepikova, M.; Lavenant, N.

    2011-12-01

    For prediction of flow and transport in fractured media, prior estimation of the fracture network is essential, but challenging. Recent developments in hydraulic tomography have shown promising results for understanding connectivities between boreholes. However, as the hydraulic tomographic survey is typically based on the propagation of head only, it becomes a strongly non unique problem. To reduce the non uniqueness of tomographic surveys point conditioning has been found beneficial. Just as well, measurement of local flow in a fracture can serve as point conditioning for hydraulic and tracer tomographic surveys. Nevertheless, only few measurements of local fracture flow have been performed since this type of measurements implies several important technical issues. Dilution test in a packed off interval is a possible method for measuring fracture flow (e.g. Drost et al. 1968, Novakowski et al., 2005). However, a key issue for estimating flow with dilution tests is to ensure a full mixing of the tracer in the packed interval. This is typically done by including a mixing system within the packer. The design of such system can be challenging for deep wells and small diameters. Here, we propose a method where mixing is ensured by a recirculation loop including a surface tank. This method is adapted from the design proposed by Brouyere et al. (2008), who measured dilution in open wells. Dilution is quantified by measuring the concentration in the surface barrel as function of time. Together with the measurement of the circulating flow and the water filled volume in the surface barrel, the measured tracer dilution allows for calculation of the fracture flow. Since the method can be applied using a classical double packer system, it may provide a broader application of local flow measurements in heterogeneous media. We tested the approach on the Ploemeur fractured crystalline rock site. A one meter interval at depth 80 m with a single flowing fracture was isolated with

  17. Flow and diffusion of high-stakes test scores.

    PubMed

    Marder, M; Bansal, D

    2009-10-13

    We apply visualization and modeling methods for convective and diffusive flows to public school mathematics test scores from Texas. We obtain plots that show the most likely future and past scores of students, the effects of random processes such as guessing, and the rate at which students appear in and disappear from schools. We show that student outcomes depend strongly upon economic class, and identify the grade levels where flows of different groups diverge most strongly. Changing the effectiveness of instruction in one grade naturally leads to strongly nonlinear effects on student outcomes in subsequent grades.

  18. Magnetic Nanoparticle Thermometer: An Investigation of Minimum Error Transmission Path and AC Bias Error

    PubMed Central

    Du, Zhongzhou; Su, Rijian; Liu, Wenzhong; Huang, Zhixing

    2015-01-01

    The signal transmission module of a magnetic nanoparticle thermometer (MNPT) was established in this study to analyze the error sources introduced during the signal flow in the hardware system. The underlying error sources that significantly affected the precision of the MNPT were determined through mathematical modeling and simulation. A transfer module path with the minimum error in the hardware system was then proposed through the analysis of the variations of the system error caused by the significant error sources when the signal flew through the signal transmission module. In addition, a system parameter, named the signal-to-AC bias ratio (i.e., the ratio between the signal and AC bias), was identified as a direct determinant of the precision of the measured temperature. The temperature error was below 0.1 K when the signal-to-AC bias ratio was higher than 80 dB, and other system errors were not considered. The temperature error was below 0.1 K in the experiments with a commercial magnetic fluid (Sample SOR-10, Ocean Nanotechnology, Springdale, AR, USA) when the hardware system of the MNPT was designed with the aforementioned method. PMID:25875188

  19. Transthoracic Coronary Flow Data at Rest Predict High-Risk Stress Tests.

    PubMed

    Zagatina, Angela; Zhuravskaya, Nadezhda; Vareldzhyan, Yuliya; Kamenskikh, Maxim; Shmatov, Dmitry; Benacka, Jozef; Kucera, Martin; Kruzliak, Peter

    2018-06-01

    Background Several recent studies have reported the opportunity to diagnose significant narrowing of the coronary arteries without stress testing using local flow acceleration. Purpose To define how often patients with increased coronary flow velocities at rest (≥ 0.70 m/s) have a positive exercise echocardiography test. Material and Methods A total of 150 patients scheduled for exercise echocardiography were studied using transthoracic Doppler echocardiography in order to assess coronary artery flow velocity before exercise. Pulsed wave Doppler registered blood flow velocity placed on the color signal. The maximal diastolic velocity of coronary flow was measured. Results Of participants, 16% had a velocity of more than 0.70 m/s in the left main/proximal left anterior/proximal left circumflex arteries (LM/pLAD). A significant correlation was observed between the value of the maximal velocity in LM/pLAD and the ejection fraction at the peak of exercise ( r ≈ -0.39, P < 0.0001); between the value of the maximal velocity in LM/pLAD and index of wall motion abnormalities (IWMA) at the peak of exercise ( r ≈ 0.44, P < 0.0001); and between the value of the maximal velocity in LM/pLAD and dIWMA ( r ≈ 0.41, P < 0.0001). Afterwards, severe ischemia in stress echocardiography tests was observed in this group. The average IWMA of these tests was found to be 2.3. Sixty-two angiograms were available for comparison with Doppler data. Conclusion There is a significant correlation between the value of the maximal velocity in LM/pLAD/pLCx at rest and the severity of wall motion abnormalities during exercise tests.

  20. ac aging and space-charge characteristics in low-density polyethylene polymeric insulation

    NASA Astrophysics Data System (ADS)

    Chen, G.; Fu, M.; Liu, X. Z.; Zhong, L. S.

    2005-04-01

    In the present work efforts have been made to investigate the influence of ac aging on space-charge dynamics in low-density polyethylene (LDPE). LDPE films with 200 μm were aged under various electric stress levels at 50 Hz for various times at ambient temperature. Space-charge dynamics in the samples after aging were monitored using the pulsed electroacoustic technique. It has been revealed that the space charge under ac aging conditions is related to the level of the applied field, duration of the voltage application, as well as the electrode materials. By comparing with the results of unaged sample the results from aged sample provide a direct evidence of changing trapping characteristics after ac aging. Negative space charge is present in the bulk of the material and the total amount of charge increases with the aging time. The amount of charge increases with the applied field. Charge decay test indicates that the charges are captured in deep traps. These deep traps are believed to form during the aging and related to change caused by injected charge. By using different electrode materials such as gold, brass alloy, and polyethylene loaded with carbon black, it was found that the electrode has an important role in the formation of charge, hence subsequent changes caused by charge. The charge dynamics of the aged samples under dc bias differ from the sample without ac aging, indicating changes brought in by ac aging. Chemical analysis by Fourier transform infrared spectroscope and Raman microscope reveals no detectable chemical changes taken place in the bulk of the material after ac aging. Finally, the consequence of the accumulation of space charge under ac conditions on the lifetime of the material has been discussed. The presence of deeply trapped space charge leads to an electric stress enhancement which may shorten the lifetime of the insulation system.

  1. Effects of mycophenolate mofetil on proliferation and mucin-5AC expression in human conjunctival goblet cells in vitro.

    PubMed

    He, Hong; Ding, Hui; Liao, Aiping; Liu, Qiong; Yang, Jun; Zhong, Xingwu

    2010-10-01

    To investigate the effects of mycophenolate mofetil (MMF) on proliferation and mucin-5AC (MUC5AC) mRNA expression of normal human conjunctival goblet cells (CGCs) in vitro and to understand mechanisms of MMF in treatment of dry eye syndrome at molecular level. Purified human CGCs were treated with a series of graded concentrations of MMF after being confirmed by immunocytochemistry and flow cytometry. Proliferation and MUC5AC mRNA expression of CGCs were measured by Cell Count Kit-8 (CCK-8) and quantitative nested real-time reverse transcription polymerase chain reaction (QNRT-PCR at 24 h after treatment. The cell proliferation and MUC5AC mRNA expressiion were compared among different doses of MMF. MMF induced a dose-dependent upregulation of MUC5AC mRNA expression (F=238.851, p<0.01) but a biphase effect on proliferation of the CGCs over 24 h of co-incubation. This biphase effect manifested as a dose-dependent increase in cell numbers with MMF from 0.25 to 2.5 ng/ml, an unchanged population of the cells from 2.5 to 10 ng/ml and a reduced population of the cells from 25 to 100 ng/ml. MMF exerts biphase effects on cell regeneration and upregulates MUC5AC mRNA expression in CGCs in vitro. It appears that the use of MMF at low concentrations is attractive in dry eye (DE) treatment.

  2. ac response of thin superconductors in the flux-creep regime

    NASA Astrophysics Data System (ADS)

    Gurevich, A.; Brandt, E. H.

    1997-05-01

    below the irreversibility field, where s(T,B)<<1. Magnetization and ac losses at B0>>:Bh are calculated accounting for the nonlinearity of E(J) at Jflow and flux creep at J~=Jc. All these regimes were confirmed by our computer simulations of nonlinear flux diffusion in strips and disks.

  3. Pestalactams A-C: novel caprolactams from the endophytic fungus Pestalotiopsis sp.

    PubMed

    Davis, Rohan A; Carroll, Anthony R; Andrews, Katherine T; Boyle, Glen M; Tran, Truc Linh; Healy, Peter C; Kalaitzis, John A; Shivas, Roger G

    2010-04-21

    Chemical investigations of a fermentation culture from the endophytic fungus Pestalotiopsis sp. yielded three novel caprolactams, pestalactams A-C (). The structures of were determined by analysis of 1D and 2D-NMR, UV, IR, and MS data. The structure of pestalactam A was confirmed following single crystal X-ray diffraction analysis. Pestalactams A-C are the first C-7 alkylated caprolactam natural products to be reported. Pestalactams A () and B () were tested against two different strains of the malaria parasite Plasmodium falciparum (3D7 and Dd2), and the mammalian cell lines, MCF-7 and NFF, and showed modest in vitro activity in all assays.

  4. Spectroscopic Determination of the AC Voltammetric Response.

    DTIC Science & Technology

    1984-01-06

    characterization of electrode processes. More recently, with the advent of linear sweep cyclic AC voltanmetry(12’ 13), it has been shown that AC methods...implemented with the same instrumentation ( 7 ) as previously used in MSRS and retains both the qualitative and quantitative utility of linear sweep ...voltammetric response (eg. peak width at balf-height, peak separation and cross-over potential in cyclic AC voltametry ) apply equally well to the SACRS

  5. THERMIONIC AC GENERATION

    DTIC Science & Technology

    is shown that the maximum ac efficiency is equal to approximately 70% of the corresponding dc value. An illustrative example, including a proposed design for a rather unconventional transformer, is appended. (Author)

  6. 78 FR 49318 - Availability of Draft Advisory Circular (AC) 90-106A and AC 20-167A

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-08-13

    ... DEPARTMENT OF TRANSPORTATION Federal Aviation Administration [Docket No FAA-2013-0485] Availability of Draft Advisory Circular (AC) 90-106A and AC 20- 167A AGENCY: Federal Aviation Administration..., Federal Aviation Administration, 800 Independence Avenue SW., Washington, DC 20591; telephone (202) 385...

  7. Progress on advanced dc and ac induction drives for electric vehicles

    NASA Technical Reports Server (NTRS)

    Schwartz, H. J.

    1982-01-01

    Progress is reported in the development of complete electric vehicle propulsion systems, and the results of tests on the Road Load Simulator of two such systems representative of advanced dc and ac drive technology are presented. One is the system used in the DOE's ETV-1 integrated test vehicle which consists of a shunt wound dc traction motor under microprocessor control using a transistorized controller. The motor drives the vehicle through a fixed ratio transmission. The second system uses an ac induction motor controlled by transistorized pulse width modulated inverter which drives through a two speed automatically shifted transmission. The inverter and transmission both operate under the control of a microprocessor. The characteristics of these systems are also compared with the propulsion system technology available in vehicles being manufactured at the inception of the DOE program and with an advanced, highly integrated propulsion system upon which technology development was recently initiated.

  8. A FLOW-THROUGH TESTING PROCEDURE WITH DUCKWEED (LEMNA MINOR L.)

    EPA Science Inventory

    Lemna minor is one of the smallest flowering plants. Because of its floating habit, ease of culture, and small size it is well adapted for laboratory investigations. Procedures for flow-through tests were developed. Testing procedures were developed with this apparatus. By using ...

  9. Differential Roles of AC2 and AC4 of Cassava Geminiviruses in Mediating Synergism and Suppression of Posttranscriptional Gene Silencing

    PubMed Central

    Vanitharani, Ramachandran; Chellappan, Padmanabhan; Pita, Justin S.; Fauquet, Claude M.

    2004-01-01

    Posttranscriptional gene silencing (PTGS) in plants is a natural defense mechanism against virus infection. In mixed infections, virus synergism is proposed to result from suppression of the host defense mechanism by the viruses. Synergistic severe mosaic disease caused by simultaneous infection with isolates of the Cameroon strain of African cassava mosaic virus (ACMV-[CM]) and East African cassava mosaic Cameroon virus (EACMCV) in cassava and tobacco is characterized by a dramatic increase in symptom severity and a severalfold increase in viral-DNA accumulation by both viruses compared to that in singly infected plants. Here, we report that synergism between ACMV-[CM] and EACMCV is a two-way process, as the presence of the DNA-A component of ACMV-[CM] or EACMCV in trans enhanced the accumulation of viral DNA of EACMCV and ACMV-[CM], respectively, in tobacco BY-2 protoplasts. Furthermore, transient expression of ACMV-[CM] AC4 driven by the Cauliflower mosaic virus 35S promoter (p35S-AC4) enhanced EACMCV DNA accumulation by ∼8-fold in protoplasts, while p35S-AC2 of EACMCV enhanced ACMV-[CM] DNA accumulation, also by ∼8-fold. An Agrobacterium-based leaf infiltration assay determined that ACMV-[CM] AC4 and EACMCV AC2, the putative synergistic genes, were able to suppress PTGS induced by green fluorescent protein (GFP) and eliminated the short interfering RNAs associated with PTGS, with a correlated increase in GFP mRNA accumulation. In addition, we have identified AC4 of Sri Lankan cassava mosaic virus and AC2 of Indian cassava mosaic virus as suppressors of PTGS, indicating that geminiviruses evolved differently in regard to interaction with the host. The specific and different roles played by these AC2 and AC4 proteins of cassava geminiviruses in regulating anti-PTGS activity and their relation to synergism are discussed. PMID:15308741

  10. 21 CFR 880.6320 - AC-powered medical examination light.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false AC-powered medical examination light. 880.6320... Miscellaneous Devices § 880.6320 AC-powered medical examination light. (a) Identification. An AC-powered medical examination light is an AC-powered device intended for medical purposes that is used to illuminate body...

  11. Development of an Axisymmetric Afterbody Test Case for Turbulent Flow Separation Validation

    NASA Technical Reports Server (NTRS)

    Disotell, Kevin J.; Rumsey, Christopher L.

    2017-01-01

    As identified in the CFD Vision 2030 Study commissioned by NASA, validation of advanced RANS models and scale-resolving methods for computing turbulent flows must be supported by improvements in high-quality experiments designed specifically for CFD implementation. A new test platform referred to as the Axisymmetric Afterbody allows for a range of flow behaviors to be studied on interchangeable afterbodies while facilitating access to higher Reynolds number facilities. A priori RANS computations are reported for a risk-reduction configuration to demonstrate critical variation among turbulence model results for a given afterbody, ranging from barely-attached to mild separated flow. The effects of body nose geometry and tunnel-wall boundary condition on the computed afterbody flow are explored to inform the design of an experimental test program.

  12. High voltage AC plasma torches with long electric arcs for plasma-chemical applications

    NASA Astrophysics Data System (ADS)

    Surov, A. V.; Popov, S. D.; Serba, E. O.; Pavlov, A. V.; Nakonechny, Gh V.; Spodobin, V. A.; Nikonov, A. V.; Subbotin, D. I.; Borovskoy, A. M.

    2017-04-01

    Powerful AC plasma torches are in demand for a number of advanced plasma chemical applications, they can provide high enthalpy of the working gas. IEE RAS specialists have developed a number of models of stationary thermal plasma torches for continuous operation on air with the power from 5 to 500 kW, and on mixture of H2O, CO2 and CH4 up to 150 kW. AC plasma torches were tested on the pilot plasmachemical installations. Powerful AC plasma torch with hollow electrodes and the gas vortex stabilization of arc in cylindrical channels and its operation characteristics are presented. Lifetime of its continuous operation on air is 2000 hours and thermal efficiency is about 92%, the electric arc length between two electrodes of the plasma torch exceeds 2 m.

  13. High-frequency ac power distribution in Space Station

    NASA Technical Reports Server (NTRS)

    Tsai, Fu-Sheng; Lee, Fred C. Y.

    1990-01-01

    A utility-type 20-kHz ac power distribution system for the Space Station, employing resonant power-conversion techniques, is presented. The system converts raw dc voltage from photovoltaic cells or three-phase LF ac voltage from a solar dynamic generator into a regulated 20-kHz ac voltage for distribution among various loads. The results of EASY5 computer simulations of the local and global performance show that the system has fast response and good transient behavior. The ac bus voltage is effectively regulated using the phase-control scheme, which is demonstrated with both line and load variations. The feasibility of paralleling the driver-module outputs is illustrated with the driver modules synchronized and sharing a common feedback loop. An HF sinusoidal ac voltage is generated in the three-phase ac input case, when the driver modules are phased 120 deg away from one another and their outputs are connected in series.

  14. Flow list and test results

    EPA Pesticide Factsheets

    These data accompany the manuscript 'Critical Review of Elementary Flows in LCA Data'. Each file presents a subgroup of the elementary flows (data used for analysis) and all the analysis results. Files are separated by flow types. The 'Element or Compound' types contained over 115,000 flows and was broken into three files (a, b,and c). A guide to the file contents and explanation of flow types are provided in the 'CriticalReviewofElementaryFlows_Data_Guide' file.This dataset is associated with the following publication:Edelen, A., W. Ingwersen, C. Rodriguez, R. Alvarenga, A.R. de Almeida, and G. Wernet. Critical Review of Elementary Flows in LCA data. INTERNATIONAL JOURNAL OF LIFE CYCLE ASSESSMENT. Ecomed Verlagsgesellschaft AG, Landsberg, GERMANY,

  15. Core Dynamics Analysis for Reactivity Insertion and Loss of Coolant Flow Tests Using the High Temperature Engineering Test Reactor

    NASA Astrophysics Data System (ADS)

    Takamatsu, Kuniyoshi; Nakagawa, Shigeaki; Takeda, Tetsuaki

    Safety demonstration tests using the High Temperature Engineering Test Reactor (HTTR) are in progress to verify its inherent safety features and improve the safety technology and design methodology for High-temperature Gas-cooled Reactors (HTGRs). The reactivity insertion test is one of the safety demonstration tests for the HTTR. This test simulates the rapid increase in the reactor power by withdrawing the control rod without operating the reactor power control system. In addition, the loss of coolant flow tests has been conducted to simulate the rapid decrease in the reactor power by tripping one, two or all out of three gas circulators. The experimental results have revealed the inherent safety features of HTGRs, such as the negative reactivity feedback effect. The numerical analysis code, which was named-ACCORD-, was developed to analyze the reactor dynamics including the flow behavior in the HTTR core. We have modified this code to use a model with four parallel channels and twenty temperature coefficients. Furthermore, we added another analytical model of the core for calculating the heat conduction between the fuel channels and the core in the case of the loss of coolant flow tests. This paper describes the validation results for the newly developed code using the experimental results. Moreover, the effect of the model is formulated quantitatively with our proposed equation. Finally, the pre-analytical result of the loss of coolant flow test by tripping all gas circulators is also discussed.

  16. HOT PLASMA FROM SOLAR ACTIVE REGION CORES: A TEST OF AC AND DC CORONAL HEATING MODELS?

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

    Schmelz, J. T.; Christian, G. M.; Dhaliwal, R. S.

    2015-06-20

    Direct current (DC) models of solar coronal heating invoke magnetic reconnection to convert magnetic free energy into heat, whereas alternating current (AC) models invoke wave dissipation. In both cases the energy is supplied by photospheric footpoint motions. For a given footpoint velocity amplitude, DC models predict lower average heating rates but greater temperature variability when compared to AC models. Therefore, evidence of hot plasma (T > 5 MK) in the cores of active regions could be one of the ways for current observations to distinguish between AC and DC models. We have analyzed data from the X-Ray Telescope (XRT) andmore » the Atmospheric Imaging Assembly for 12 quiescent active region cores, all of which were observed in the XRT Be-thick channel. We did Differential Emission Measure (DEM) analysis and achieved good fits for each data set. We then artificially truncated the hot plasma of the DEM model at 5 MK and examined the resulting fits to the data. For some regions in our sample, the XRT intensities continued to be well-matched by the DEM predictions, even without the hot plasma. This truncation, however, resulted in unacceptable fits for the other regions. This result indicates that the hot plasma is present in these regions, even if the precise DEM distribution cannot be determined with the data available. We conclude that reconnection may be heating the hot plasma component of these active regions.« less

  17. Measured losses in superconductor magnets for 60-Hertz ac operation.

    NASA Technical Reports Server (NTRS)

    Hamlet, I. L.; Kilgore, R. A.

    1971-01-01

    Results of an experimental study of electrical losses in superconductor magnets. Preliminary 60-Hz ac loss data are presented for coils constructed of Nb3Sn ribbon, Nb-Ti cable, and multifilament Nb-Ti. Losses have been measured for different size coils up to approximately 20 cm in diameter. Of the conductor types tested, Nb3Sn ribbon has the lowest losses for ac operation. In Nb3Sn-ribbon coils of different sizes, the loss per unit length of conductor is shown to decrease with a decrease in the rate of change of current and to increase, in general, with increase in coil size. An important aspect of the study is the high degree of repeatability of the data.

  18. Scramjet test flow reconstruction for a large-scale expansion tube, Part 2: axisymmetric CFD analysis

    NASA Astrophysics Data System (ADS)

    Gildfind, D. E.; Jacobs, P. A.; Morgan, R. G.; Chan, W. Y. K.; Gollan, R. J.

    2018-07-01

    This paper presents the second part of a study aiming to accurately characterise a Mach 10 scramjet test flow generated using a large free-piston-driven expansion tube. Part 1 described the experimental set-up, the quasi-one-dimensional simulation of the full facility, and the hybrid analysis technique used to compute the nozzle exit test flow properties. The second stage of the hybrid analysis applies the computed 1-D shock tube flow history as an inflow to a high-fidelity two-dimensional-axisymmetric analysis of the acceleration tube. The acceleration tube exit flow history is then applied as an inflow to a further refined axisymmetric nozzle model, providing the final nozzle exit test flow properties and thereby completing the analysis. This paper presents the results of the axisymmetric analyses. These simulations are shown to closely reproduce experimentally measured shock speeds and acceleration tube static pressure histories, as well as nozzle centreline static and impact pressure histories. The hybrid scheme less successfully predicts the diameter of the core test flow; however, this property is readily measured through experimental pitot surveys. In combination, the full test flow history can be accurately determined.

  19. Scramjet test flow reconstruction for a large-scale expansion tube, Part 2: axisymmetric CFD analysis

    NASA Astrophysics Data System (ADS)

    Gildfind, D. E.; Jacobs, P. A.; Morgan, R. G.; Chan, W. Y. K.; Gollan, R. J.

    2017-11-01

    This paper presents the second part of a study aiming to accurately characterise a Mach 10 scramjet test flow generated using a large free-piston-driven expansion tube. Part 1 described the experimental set-up, the quasi-one-dimensional simulation of the full facility, and the hybrid analysis technique used to compute the nozzle exit test flow properties. The second stage of the hybrid analysis applies the computed 1-D shock tube flow history as an inflow to a high-fidelity two-dimensional-axisymmetric analysis of the acceleration tube. The acceleration tube exit flow history is then applied as an inflow to a further refined axisymmetric nozzle model, providing the final nozzle exit test flow properties and thereby completing the analysis. This paper presents the results of the axisymmetric analyses. These simulations are shown to closely reproduce experimentally measured shock speeds and acceleration tube static pressure histories, as well as nozzle centreline static and impact pressure histories. The hybrid scheme less successfully predicts the diameter of the core test flow; however, this property is readily measured through experimental pitot surveys. In combination, the full test flow history can be accurately determined.

  20. Intelligent Network Flow Optimization (INFLO) prototype acceptance test summary.

    DOT National Transportation Integrated Search

    2015-05-01

    This report summarizes the results of System Acceptance Testing for the implementation of the Intelligent Network Flow Optimization (INFLO) Prototype bundle within the Dynamic Mobility Applications (DMA) portion of the Connected Vehicle Program. This...

  1. Design and Implementation of a Characterization Test Rig for Evaluating High Bandwidth Liquid Fuel Flow Modulators

    NASA Technical Reports Server (NTRS)

    Saus, Joseph R.; Chang, Clarence T.; DeLaat, John C.; Vrnak, Daniel R.

    2010-01-01

    A test rig was designed and developed at the NASA Glenn Research Center (GRC) for the purpose of characterizing high bandwidth liquid fuel flow modulator candidates to determine their suitability for combustion instability control research. The test rig is capable of testing flow modulators at up to 600 psia supply pressure and flows of up to 2 gpm. The rig is designed to provide a quiescent flow into the test section in order to isolate the dynamic flow modulations produced by the test article. Both the fuel injector orifice downstream of the test article and the combustor are emulated. The effect of fuel delivery line lengths on modulator dynamic performance can be observed and modified to replicate actual fuel delivery systems. For simplicity, water is currently used as the working fluid, although future plans are to use jet fuel. The rig is instrumented for dynamic pressures and flows and a high-speed data system is used for dynamic data acquisition. Preliminary results have been obtained for one candidate flow modulator.

  2. Transcranial Alternating Current Stimulation (tACS) Mechanisms and Protocols

    PubMed Central

    Tavakoli, Amir V.; Yun, Kyongsik

    2017-01-01

    Perception, cognition and consciousness can be modulated as a function of oscillating neural activity, while ongoing neuronal dynamics are influenced by synaptic activity and membrane potential. Consequently, transcranial alternating current stimulation (tACS) may be used for neurological intervention. The advantageous features of tACS include the biphasic and sinusoidal tACS currents, the ability to entrain large neuronal populations, and subtle control over somatic effects. Through neuromodulation of phasic, neural activity, tACS is a powerful tool to investigate the neural correlates of cognition. The rapid development in this area requires clarity about best practices. Here we briefly introduce tACS and review the most compelling findings in the literature to provide a starting point for using tACS. We suggest that tACS protocols be based on functional brain mechanisms and appropriate control experiments, including active sham and condition blinding. PMID:28928634

  3. Core flow inversion tested with numerical dynamo models

    NASA Astrophysics Data System (ADS)

    Rau, Steffen; Christensen, Ulrich; Jackson, Andrew; Wicht, Johannes

    2000-05-01

    We test inversion methods of geomagnetic secular variation data for the pattern of fluid flow near the surface of the core with synthetic data. These are taken from self-consistent 3-D models of convection-driven magnetohydrodynamic dynamos in rotating spherical shells, which generate dipole-dominated magnetic fields with an Earth-like morphology. We find that the frozen-flux approximation, which is fundamental to all inversion schemes, is satisfied to a fair degree in the models. In order to alleviate the non-uniqueness of the inversion, usually a priori conditions are imposed on the flow; for example, it is required to be purely toroidal or geostrophic. Either condition is nearly satisfied by our model flows near the outer surface. However, most of the surface velocity field lies in the nullspace of the inversion problem. Nonetheless, the a priori constraints reduce the nullspace, and by inverting the magnetic data with either one of them we recover a significant part of the flow. With the geostrophic condition the correlation coefficient between the inverted and the true velocity field can reach values of up to 0.65, depending on the choice of the damping parameter. The correlation is significant at the 95 per cent level for most spherical harmonic degrees up to l=26. However, it degrades substantially, even at long wavelengths, when we truncate the magnetic data sets to l <= 14, that is, to the resolution of core-field models. In some of the latter inversions prominent zonal currents, similar to those seen in core-flow models derived from geomagnetic data, occur in the equatorial region. However, the true flow does not contain this flow component. The results suggest that some meaningful information on the core-flow pattern can be retrieved from secular variation data, but also that the limited resolution of the magnetic core field could produce serious artefacts.

  4. Challenges and solutions in medically managed ACS in the Asia-Pacific region: expert recommendations from the Asia-Pacific ACS Medical Management Working Group.

    PubMed

    Huo, Yong; Thompson, Peter; Buddhari, Wacin; Ge, Junbo; Harding, Scott; Ramanathan, Letchuman; Reyes, Eugenio; Santoso, Anwar; Tam, Li-Wah; Vijayaraghavan, Govindan; Yeh, Hung-I

    2015-03-15

    Acute coronary syndromes (ACS) remain a leading cause of mortality and morbidity in the Asia-Pacific (APAC) region. International guidelines advocate invasive procedures in all but low-risk ACS patients; however, a high proportion of ACS patients in the APAC region receive solely medical management due to a combination of unique geographical, socioeconomic, and population-specific barriers. The APAC ACS Medical Management Working Group recently convened to discuss the ACS medical management landscape in the APAC region. Local and international ACS guidelines and the global and APAC clinical evidence-base for medical management of ACS were reviewed. Challenges in the provision of optimal care for these patients were identified and broadly categorized into issues related to (1) accessibility/systems of care, (2) risk stratification, (3) education, (4) optimization of pharmacotherapy, and (5) cost/affordability. While ACS guidelines clearly represent a valuable standard of care, the group concluded that these challenges can be best met by establishing cardiac networks and individual hospital models/clinical pathways taking into account local risk factors (including socioeconomic status), affordability and availability of pharmacotherapies/invasive facilities, and the nature of local healthcare systems. Potential solutions central to the optimization of ACS medical management in the APAC region are outlined with specific recommendations. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

  5. Functional dilatation and medial remodeling of the renal artery in response to chronic increased blood flow.

    PubMed

    Roan, Jun-Neng; Yeh, Chin-Yi; Chiu, Wen-Cheng; Lee, Chou-Hwei; Chang, Shih-Wei; Jiangshieh, Ya-Fen; Tsai, Yu-Chuan; Lam, Chen-Fuh

    2011-01-01

    Renal blood flow (RBF) is tightly regulated by several intrinsic pathways in maintaining optimal kidney blood supply. Using a rat model of aortocaval (AC) fistula, we investigated remodeling of the renal artery following prolonged increased blood flow. An AC fistula was created in the infrarenal aorta of anesthetized rats, and changes of blood flow in the renal artery were assessed using an ultrasonic flow probe. Morphological changes and expression of endothelial nitric oxide synthase and matrix metalloproteinase-2 in the remodeled renal artery were analyzed. Blood flow in the renal artery increased immediately after creation of AC fistula, but normal RBF was restored 8 weeks later. The renal artery dilated significantly 8 weeks after operation. Expression of endothelial nitric oxide synthase and matrix metalloproteinase-2 was upregulated shortly after blood flow increase, and returned to baseline levels after 3 weeks. Histological sections showed luminal dilatation with medial thickening and endothelial cell-to-smooth muscle cell attachments in the remodeled renal artery. Increased RBF was accommodated by functional dilatation and remodeling in the medial layer of the renal artery in order to restore normal blood flow. Our results provide important mechanistic insight into the intrinsic regulation of the renal artery in response to increased RBF. Copyright © 2011 S. Karger AG, Basel.

  6. Infrequent transposition of Ac in lettuce, Lactuca sativa.

    PubMed

    Yang, C H; Ellis, J G; Michelmore, R W

    1993-08-01

    The maize transposable element Activator (Ac) is being used to develop a transposon mutagenesis system in lettuce, Lactuca sativa. Two constructs containing the complete Ac from the waxy-m7 locus of maize were introduced into lettuce and monitored for activity using Southern analysis and PCR amplification of the excision site. No transposition of Ac was detected in over 32 transgenic R1 plants, although these constructs were known to provide frequent transposition in other species. Also, no transposition was observed in later generations. In subsequent experiments, transposition was detected in lettuce calli using constructs that allowed selection for excision events. In these constructs, the neomycin phosphotransferase II gene was interrupted by either Ac or Ds. Excision was detected as the ability of callus to grow on kanamycin. Synthesis of the transposase from the cDNA of Ac expressed from the T-DNA 2' promoter resulted in more frequent excision of Ds than was observed with the wild-type Ac. No excision was observed with Ds in the absence of the transposase. The excision events were confirmed by amplification of the excision site by PCR followed by DNA sequencing. Excision and reintegration were also confirmed by Southern analysis. Ac/Ds is therefore capable of transposition in at least calli of lettuce.

  7. Geological mechanism of hazardous debris flows in central Taiwan

    NASA Astrophysics Data System (ADS)

    Chen, H.; Chen, R. H.; Lin, M. L.; Su, D. Y.

    2003-04-01

    GEOLOGICAL MECHANISM OF HAZARDOUS DEBRIS FLOWS IN CENTRAL PART OF TAIWAN H. Chen (1), R. H. Chen (2), M. L. Lin (2), D.Y. Su (3) (1) Department of Geosciences, National Taiwan University, (2) Department of Civil Engineering, National Taiwan University, (3) MAA Ltd., Taiwan hche02@esc.cam.ac.uk/Fax:+44-01223-333450 This study revealed that the distribution of rock discontinuities, geomaterial characteristics and water pressure were the major hazardous factors of the triggering mechanism in the debris flows. Attention is drawn to the discontinuities pattern within the sidewalls of the gullies, which emphasized the significance of material slumping and forming the accumulated deposits in the gullies. The accumulated deposits are the main source of the debris flow once the disaster is triggered and produced large quantities of debris. A modified channel box test was used to comprehend the effect of water sources in this study. The results of this experimental test displayed that water supplied from the bottom or the top will both cause large material movement. But water supplied from the bottom tends to cause a larger and faster flow than water from the top. The visual evidence of a flushed network of discontinuities exposed after the debris flow provided in situ indications of increased pore water pressure. This rapidly increasing water pressure evidently contributed a sizable dynamic force to initiate movement of the debris flow. The heavy slurry became an effective cutting device to erode the sidewalls and move large quantities of the debris materials to the end of the gullies. Based on field investigations and laboratory tests, the precipitation could increase the water content and water pressure, and decrease the shear strength of the gullies material. It also can add confirmation to this research that debris flows are triggered by accumulated deposits from sidewalls and moved by high intensity precipitation.

  8. Resource utilization and outcome among patients with selective versus nonselective troponin testing.

    PubMed

    Campbell, Alex R; Rodriguez, Alexander J; Larson, David M; Strauss, Craig E; Garberich, Ross F; Partridge, Matthew F; Henry, Timothy D; Sharkey, Scott W

    2018-05-01

    In patients with suspected acute coronary syndrome (ACS), troponin testing is effective for diagnosis and prognosis. Troponin testing has now expanded to include patients without suspected ACS. This nonselective troponin testing has unknown consequences for resource utilization and outcome. Therefore, we examined selective versus nonselective troponin testing with respect to patient characteristics, resource utilization, and outcome. This retrospective 1-year study included all patients with troponin testing at a U.S. emergency department. Testing was classified as selective (ACS) or nonselective (non-ACS) based on admission ICD-9 codes. Troponin upper reference limit (URL) was ≥99th percentile. Among 47,053 patients, troponin was measured in 9109 (19%) of whom 5764 were hospitalized. Admission diagnosis was non-ACS in 4427 (77%) and ACS in 1337 (23%). Non-ACS patients were older, 71±17 versus 65±16 years, with longer hospital stay, 77 versus 32 h, and greater 1-year mortality 22% versus 6.7%; P<.001. In patients with troponin ≥URL, revascularization was performed in 64 (4.7%) of non-ACS versus 213 (48%) of ACS; P<.001. In patients with troponin ACS versus 3.5% in ACS; P<.001. In those with troponin ≥URL, 1-year mortality was 35% in non-ACS versus 13% in ACS; P<.001. Death was non-cardiac in >80% of the non-ACS population CONCLUSIONS: Contemporary troponin testing is frequently nonselective. The non-ACS and ACS populations differ significantly regarding clinical characteristics, revascularization rates, and outcomes. Troponin elevation is a powerful predictor of 1-year mortality in non-ACS, this association reveals an opportunity for risk stratification and targeted therapy. In patients with suspected acute coronary syndrome (ACS), troponin testing is effective for diagnosis and prognosis. However, troponin testing has now expanded to include patients without suspected ACS. This nonselective troponin testing has unknown

  9. Test problems for inviscid transonic flow

    NASA Technical Reports Server (NTRS)

    Carlson, L. A.

    1979-01-01

    Solving of test problems with the TRANDES program is discussed. This method utilizes the full, inviscid, perturbation potential flow equation in a Cartesian grid system that is stretched to infinity. This equation is represented by a nonconservative system of finite difference equations that includes at supersonic points a rotated difference scheme and is solved by column relaxation. The solution usually starts from a zero perturbation potential on a very coarse grid (typically 13 by 7) followed by several grid halvings until a final solution is obtained on a fine grid (97 by 49).

  10. Promoted Ignition and Burning Tests of Stainless Steel in Flowing and Nonflowing Oxygen

    NASA Technical Reports Server (NTRS)

    Forsyth, Elliot T.; Maes, Miguel; Stoltzfus, Joel M.; Bachelier, Frederic

    2003-01-01

    The Industry-Sponsored Metals Combustion Test Program 96-1 was coordinated through Wendell Hull & Associates, Inc. on behalf of several contributing companies, and all design and testing was performed at the NASA White Sands Test Facility. Phase I of this test program studied the threshold pressure for self-sustained burning of various types and sizes of stain less steel rods in nonflowing oxygen, as observed in Standard Test Method for Determining the Combustion Behavior of Metallic Materials in Oxygen-Enriched Atmospheres (ASTM G 124-95). Phase II studied the ignition and propagation of burning of 316L stainless steel rods and pipe in flowing gaseous oxygen. The test sample configurations were chosen to replicate previous promoted ignition and burning tests as well as to represent geometries and cross-sectional thicknesses common in industrial piping applications. The gas pressw'es and velocities for the test matrix were selected to generally compare with CGA G-4.4 guidelines for the use of stain less steel in oxygen service. This paper summarizes the results from the Phase I nonflowing oxygen tests and presents in detail the results of the Phase II flowing oxygen tests. The maximum sample burn-length is shown as a function of test pressure in Phase 1 and also as a function of gas velocity in Phase IT. These results indicate that flowing oxygen, under the given test conditions, significantly affects maximum sample burn length as compared to nonflowing oxygen. Supplementary flowing oxygen test data on stainless steel rods from a follow-up test program are consistent with these results and are presented herein.

  11. Transgenic cotton coexpressing Vip3A and Cry1Ac has a broad insecticidal spectrum against lepidopteran pests.

    PubMed

    Chen, Wen-Bo; Lu, Guo-Qing; Cheng, Hong-Mei; Liu, Chen-Xi; Xiao, Yu-Tao; Xu, Chao; Shen, Zhi-Cheng; Wu, Kong-Ming

    2017-10-01

    Although farmers in China have grown transgenic Bt-Cry1Ac cotton to resist the major pest Helicoverpa armigera since 1997 with great success, many secondary lepidopteran pests that are tolerant to Cry1Ac are now reported to cause considerable economic damage. Vip3AcAa, a chimeric protein with the N-terminal part of Vip3Ac and the C-terminal part of Vip3Aa, has a broad insecticidal spectrum against lepidopteran pests and has no cross resistance to Cry1Ac. In the present study, we tested insecticidal activities of Vip3AcAa against Spodoptera litura, Spodoptera exigua, and Agrotis ipsilon, which are relatively tolerant to Cry1Ac proteins. The bioassay results showed that insecticidal activities of Vip3AcAa against these three pests are superior to Cry1Ac, and after an activation pretreatment, Vip3AcAa retained insecticidal activity against S. litura, S. exigua and A. ipsilon that was similar to the unprocessed protein. The putative receptor for this chimeric protein in the brush border membrane vesicle (BBMV) in the three pests was also identified using biotinylated Vip3AcAa toxin. To broaden Bt cotton activity against a wider spectrum of pests, we introduced the vip3AcAa and cry1Ac genes into cotton. Larval mortality rates for S. litura, A. ipsilon and S. exigua that had fed on this new cotton increased significantly compared with larvae fed on non-Bt cotton and Bt-Cry1Ac cotton in a laboratory experiment. These results suggested that the Vip3AcAa protein is an excellent option for a "pyramid" strategy for integrated pest management in China. Copyright © 2017 Elsevier Inc. All rights reserved.

  12. Calibration of sonic valves for the laminar flow control, leading-edge flight test

    NASA Technical Reports Server (NTRS)

    Petley, D. H.; Alexander, W., Jr.; Wright, A. S., Jr.; Vallas, M.

    1985-01-01

    Sonic needle valves were calibrated to measure and control airflow in the suction system for the leading-edge flight test. The procedure and results for the calibration flow test of 4:41 flight valves are given. Mass-flow rates, which ranged from 0.001 to 0.012 lbm/sec, and maximum back pressure were measured for total temperatures from -30 F to 75 F and total pressures from 120 to 540 psf. Correlating equations are obtained for mass-flow rate as a function of total pressure, total temperature, and valve opening length. The most important aspect of flow measurement and control is found to be the measurement of valve opening length.

  13. Continuous flow nanoparticle concentration using alternating current-electroosmotic flow.

    PubMed

    Hoettges, Kai F; McDonnell, Martin B; Hughes, Michael P

    2014-02-01

    Achieving real-time detection of environmental pathogens such as viruses and bacterial spores requires detectors with both rapid action and a suitable detection threshold. However, most biosensors have detection limits of an order of magnitude or more above the potential infection threshold, limiting their usefulness. This can be improved through the use of automated sample preparation techniques such as preconcentration. In this paper, we describe the use of AC electroosmosis to concentrate nanoparticles from a continuous flow. Electrodes at an optimized angle across a flow cell, and energized by a 1 kHz signal, were used to push nanoparticles to one side of a flow cell, and to extract the resulting stream with a high particle concentration from that side of the flow cell. A simple model of the behavior of particles in the flow cell has been developed, which shows good agreement with experimental results. The method indicates potential for higher concentration factors through cascading devices. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  14. Bioinformatics and Astrophysics Cluster (BinAc)

    NASA Astrophysics Data System (ADS)

    Krüger, Jens; Lutz, Volker; Bartusch, Felix; Dilling, Werner; Gorska, Anna; Schäfer, Christoph; Walter, Thomas

    2017-09-01

    BinAC provides central high performance computing capacities for bioinformaticians and astrophysicists from the state of Baden-Württemberg. The bwForCluster BinAC is part of the implementation concept for scientific computing for the universities in Baden-Württemberg. Community specific support is offered through the bwHPC-C5 project.

  15. 7 CFR 1737.31 - Area Coverage Survey (ACS).

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 7 Agriculture 11 2011-01-01 2011-01-01 false Area Coverage Survey (ACS). 1737.31 Section 1737.31... Studies-Area Coverage Survey and Loan Design § 1737.31 Area Coverage Survey (ACS). (a) The Area Coverage Survey (ACS) is a market forecast of service requirements of subscribers in a proposed service area. (b...

  16. 7 CFR 1737.31 - Area Coverage Survey (ACS).

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 7 Agriculture 11 2010-01-01 2010-01-01 false Area Coverage Survey (ACS). 1737.31 Section 1737.31... Studies-Area Coverage Survey and Loan Design § 1737.31 Area Coverage Survey (ACS). (a) The Area Coverage Survey (ACS) is a market forecast of service requirements of subscribers in a proposed service area. (b...

  17. 7 CFR 1737.31 - Area Coverage Survey (ACS).

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 7 Agriculture 11 2013-01-01 2013-01-01 false Area Coverage Survey (ACS). 1737.31 Section 1737.31... Studies-Area Coverage Survey and Loan Design § 1737.31 Area Coverage Survey (ACS). (a) The Area Coverage Survey (ACS) is a market forecast of service requirements of subscribers in a proposed service area. (b...

  18. 7 CFR 1737.31 - Area Coverage Survey (ACS).

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 7 Agriculture 11 2012-01-01 2012-01-01 false Area Coverage Survey (ACS). 1737.31 Section 1737.31... Studies-Area Coverage Survey and Loan Design § 1737.31 Area Coverage Survey (ACS). (a) The Area Coverage Survey (ACS) is a market forecast of service requirements of subscribers in a proposed service area. (b...

  19. 7 CFR 1737.31 - Area Coverage Survey (ACS).

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... Studies-Area Coverage Survey and Loan Design § 1737.31 Area Coverage Survey (ACS). (a) The Area Coverage Survey (ACS) is a market forecast of service requirements of subscribers in a proposed service area. (b... 7 Agriculture 11 2014-01-01 2014-01-01 false Area Coverage Survey (ACS). 1737.31 Section 1737.31...

  20. 21 CFR 880.5500 - AC-powered patient lift.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false AC-powered patient lift. 880.5500 Section 880.5500... Devices § 880.5500 AC-powered patient lift. (a) Identification. An AC-powered lift is an electrically powered device either fixed or mobile, used to lift and transport patients in the horizontal or other...

  1. 21 CFR 880.5500 - AC-powered patient lift.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false AC-powered patient lift. 880.5500 Section 880.5500... Devices § 880.5500 AC-powered patient lift. (a) Identification. An AC-powered lift is an electrically powered device either fixed or mobile, used to lift and transport patients in the horizontal or other...

  2. Analysis of Drop Oscillations Excited by an Electrical Point Force in AC EWOD

    NASA Astrophysics Data System (ADS)

    Oh, Jung Min; Ko, Sung Hee; Kang, Kwan Hyoung

    2008-03-01

    Recently, a few researchers have reported the oscillation of a sessile drop in AC EWOD (electrowetting on dielectrics), and some of its consequences. The drop oscillation problem in AC EWOD is associated with various applications based on electrowetting such as LOC (lab-on-a-chip), liquid lens, and electronic display. However, no theoretical analysis of the problem has been attempted yet. In the present paper, we propose a theoretical model to analyze the oscillation by applying the conventional method to analyze the drop oscillation. The domain perturbation method is used to derive the shape mode equations under the assumptions of weak viscous flow and small deformation. The Maxwell stress is exerted on the three-phase contact line of the droplet like a point force. The force is regarded as a delta function, and is decomposed into the driving forces of each shape mode. The theoretical results on the shape and the frequency responses are compared with experiments, which shows a qualitative agreement.

  3. Evaluation of the in vivo genotoxicity of Allura Red AC (Food Red No. 40).

    PubMed

    Honma, Masamitsu

    2015-10-01

    Allura Red AC (Food Red No. 40) is a red azo dye that is used for food coloring in beverage and confectionary products. However, its genotoxic properties remain controversial. To clarify the in vivo genotoxicity, we treated mice with Allura Red AC and investigated the induction of DNA damage (liver, glandular stomach), clastogenicity/anuegenicity (bone marrow), and mutagenicity (liver, glandular stomach) using Comet assays, micronucleus tests, and transgenic gene mutation assays, respectively. All studies were conducted in accordance with the Organization for Economic Co-operation and Development (OECD) guideline. Although Allura Red AC was administered up to the maximum doses recommended by the OECD guideline, no genotoxic effect was observed in any of the genotoxic endpoints. These data clearly show no evidence of in vivo genotoxic potential of Allura Red AC administered up to the maximum doses in mice. Copyright © 2015 Elsevier Ltd. All rights reserved.

  4. Flap survey test of a combined surface blowing model: Flow measurements at static flow conditions

    NASA Technical Reports Server (NTRS)

    Fukushima, T.

    1978-01-01

    The Combined Surface Blowing (CSB) V/STOL lift/propulsion system consists of a blown flap system which deflects the exhaust from a turbojet engine over a system of flaps deployed at the trailing edge of the wing. Flow measurements consisting of velocity measurements using split film probes and total measure surveys using a miniature Kiel probe were made at control stations along the flap systems at two spanwise stations, the centerline of the nozzle and 60 percent of the nozzle span outboard of the centerline. Surface pressure measurements were made in the wing cove and the upper surface of the first flap element. The test showed a significant flow separation in the wing cove. The extent of the separation is so large that the flow into the first flap takes place only at the leading edge of the flap. The velocity profile measurements indicate that large spanwise (3 dimensional) flow may exist.

  5. Cloning, Expression, and Characterization of a Thermophilic Endoglucanase, AcCel12B from Acidothermus cellulolyticus 11B

    PubMed Central

    Wang, Junling; Gao, Gui; Li, Yuwei; Yang, Liangzhen; Liang, Yanli; Jin, Hanyong; Han, Weiwei; Feng, Yan; Zhang, Zuoming

    2015-01-01

    The gene ABK52392 from the thermophilic bacterium Acidothermus cellulolyticus 11B was predicted to be endoglucanase and classified into glycoside hydrolase family 12. ABK52392 encodes a protein containing a catalytic domain and a carbohydrate binding module. ABK52392 was cloned and functionally expressed in Escherichia coli. After purification by Ni-NTA agarose affinity chromatography and Q-Sepharose® Fast Flow chromatography, the properties of the recombinant protein (AcCel12B) were characterized. AcCel12B exhibited optimal activity at pH 4.5 and 75 °C. The half-lives of AcCel12B at 60 and 70 °C were about 90 and 2 h, respectively, under acidic conditions. The specific hydrolytic activities of AcCel12B at 70 °C and pH 4.5 for sodium carboxymethylcellulose (CMC) and regenerated amorphous cellulose (RAC) were 118.3 and 104.0 U·mg−1, respectively. The Km and Vmax of AcCel12B for CMC were 25.47 mg·mL−1 and 131.75 U·mg−1, respectively. The time course of hydrolysis for RAC was investigated by measuring reducing ends in the soluble and insoluble phases. The total hydrolysis rate rapidly decreased after the early stage of incubation and the generation of insoluble reducing ends decreased earlier than that of soluble reducing ends. High thermostability of the cellulase indicates its potential commercial significance and it could be exploited for industrial application in the future. PMID:26506341

  6. Linear Power-Flow Models in Multiphase Distribution Networks: Preprint

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

    Bernstein, Andrey; Dall'Anese, Emiliano

    This paper considers multiphase unbalanced distribution systems and develops approximate power-flow models where bus-voltages, line-currents, and powers at the point of common coupling are linearly related to the nodal net power injections. The linearization approach is grounded on a fixed-point interpretation of the AC power-flow equations, and it is applicable to distribution systems featuring (i) wye connections; (ii) ungrounded delta connections; (iii) a combination of wye-connected and delta-connected sources/loads; and, (iv) a combination of line-to-line and line-to-grounded-neutral devices at the secondary of distribution transformers. The proposed linear models can facilitate the development of computationally-affordable optimization and control applications -- frommore » advanced distribution management systems settings to online and distributed optimization routines. Performance of the proposed models is evaluated on different test feeders.« less

  7. A novel tool for high-throughput screening of granulocyte-specific antibodies using the automated flow cytometric granulocyte immunofluorescence test (Flow-GIFT).

    PubMed

    Nguyen, Xuan Duc; Dengler, Thomas; Schulz-Linkholt, Monika; Klüter, Harald

    2011-02-03

    Transfusion-related acute lung injury (TRALI) is a severe complication related with blood transfusion. TRALI has usually been associated with antibodies against leukocytes. The flow cytometric granulocyte immunofluorescence test (Flow-GIFT) has been introduced for routine use when investigating patients and healthy blood donors. Here we describe a novel tool in the automation of the Flow-GIFT that enables a rapid screening of blood donations. We analyzed 440 sera from healthy female blood donors for the presence of granulocyte antibodies. As positive controls, 12 sera with known antibodies against anti-HNA-1a, -b, -2a; and -3a were additionally investigated. Whole-blood samples from HNA-typed donors were collected and the test cells isolated using cell sedimentation in a Ficoll density gradient. Subsequently, leukocytes were incubated with the respective serum and binding of antibodies was detected using FITC-conjugated antihuman antibody. 7-AAD was used to exclude dead cells. Pipetting steps were automated using the Biomek NXp Multichannel Automation Workstation. All samples were prepared in the 96-deep well plates and analyzed by flow cytometry. The standard granulocyte immunofluorescence test (GIFT) and granulocyte agglutination test (GAT) were also performed as reference methods. Sixteen sera were positive in the automated Flow-GIFT, while five of these sera were negative in the standard GIFT (anti-HNA 3a, n = 3; anti-HNA-1b, n = 1) and GAT (anti-HNA-2a, n = 1). The automated Flow-GIFT was able to detect all granulocyte antibodies, which could be only detected in GIFT in combination with GAT. In serial dilution tests, the automated Flow-GIFT detected the antibodies at higher dilutions than the reference methods GIFT and GAT. The Flow-GIFT proved to be feasible for automation. This novel high-throughput system allows an effective antigranulocyte antibody detection in a large donor population in order to prevent TRALI due to transfusion of blood products.

  8. Simulated-airline-service flight tests of laminar-flow control with perforated-surface suction system

    NASA Technical Reports Server (NTRS)

    Maddalon, Dal V.; Braslow, Albert L.

    1990-01-01

    The effectiveness and practicality of candidate leading edge systems for suction laminar flow control transport airplanes were investigated in a flight test program utilizing a modified JetStar airplane. The leading edge region imposes the most severe conditions on systems required for any type of laminar flow control. Tests of the leading edge systems, therefore, provided definitive results as to the feasibility of active laminar flow control on airplanes. The test airplane was operated under commercial transport operating procedures from various commercial airports and at various seasons of the year.

  9. The AC-120: The advanced commercial transport

    NASA Technical Reports Server (NTRS)

    Duran, David; Griffin, Ernest; Mendoza, Saul; Nguyen, Son; Pickett, Tim; Noernberg, Clemm

    1993-01-01

    The main objective of this design was to fulfill a need for a new airplane to replace the aging 100 to 150 passenger, 1500 nautical mile range aircraft such as the Douglas DC9 and Boeing 737-100 airplanes. After researching the future aircraft market, conducting extensive trade studies, and analysis on different configurations, the AC-120 Advanced Commercial Transport final design was achieved. The AC-120's main design features include the incorporation of a three lifting surface configuration which is powered by two turboprop engines. The AC-120 is an economically sensitive aircraft which meets the new FM Stage Three noise requirements, and has lower NO(x) emissions than current turbofan powered airplanes. The AC-120 also improves on its contemporaries in passenger comfort, manufacturing, and operating cost.

  10. Development of a model and test equipment for cold flow tests at 500 atm of small nuclear light bulb configurations

    NASA Technical Reports Server (NTRS)

    Jaminet, J. F.

    1972-01-01

    A model and test equipment were developed and cold-flow-tested at greater than 500 atm in preparation for future high-pressure rf plasma experiments and in-reactor tests with small nuclear light bulb configurations. With minor exceptions, the model chamber is similar in design and dimensions to a proposed in-reactor geometry for tests with fissioning uranium plasmas in the nuclear furnace. The model and the equipment were designed for use with the UARL 1.2-MW rf induction heater in tests with rf plasmas at pressures up to 500 atm. A series of cold-flow tests of the model was then conducted at pressures up to about 510 atm. At 504 atm, the flow rates of argon and cooling water were 3.35 liter/sec (STP) and 26 gal/min, respectively. It was demonstrated that the model is capable of being operated for extended periods at the 500-atm pressure level and is, therefore, ready for use in initial high-pressure rf plasma experiments.

  11. Cry1Ac production is costly for native plants attacked by non-Cry1Ac-targeted herbivores in the field.

    PubMed

    McGale, Erica; Diezel, Celia; Schuman, Meredith C; Baldwin, Ian T

    2018-05-13

    Plants are the primary producers in most terrestrial ecosystems and have complex defense systems to protect their produce. Defense-deficient, high-yielding agricultural monocultures attract abundant nonhuman consumers, but are alternatively defended through pesticide application and genetic engineering to produce insecticidal proteins such as Cry1Ac (Bacillus thuringiensis). These approaches alter the balance between yield protection and maximization but have been poorly contextualized to known yield-defense trade-offs in wild plants. The native plant Nicotiana attenuata was used to compare yield benefits of plants transformed to be defenseless to those with a full suite of naturally evolved defenses, or additionally transformed to ectopically produce Cry1Ac. An insecticide treatment allowed us to examine yield under different herbivore loads in N. attenuata's native habitat. Cry1Ac, herbivore damage, and growth parameters were monitored throughout the season. Biomass and reproductive correlates were measured at season end. Non-Cry1Ac-targeted herbivores dominated on noninsecticide-treated plants, and increased the yield drag of Cry1Ac-producing plants in comparison with endogenously defended or undefended plants. Insecticide-sprayed Cry1Ac-producing plants lagged less in stalk height, shoot biomass, and flower production. In direct comparison with the endogenous defenses of a native plant, Cry1Ac production did not provide yield benefits for plants under observed herbivore loads in a field study. © 2018 The Authors New Phytologist © 2018 New Phytologist Trust.

  12. Vadose zone flow convergence test suite

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

    Butcher, B. T.

    Performance Assessment (PA) simulations for engineered disposal systems at the Savannah River Site involve highly contrasting materials and moisture conditions at and near saturation. These conditions cause severe convergence difficulties that typically result in unacceptable convergence or long simulation times or excessive analyst effort. Adequate convergence is usually achieved in a trial-anderror manner by applying under-relaxation to the Saturation or Pressure variable, in a series of everdecreasing RELAxation values. SRNL would like a more efficient scheme implemented inside PORFLOW to achieve flow convergence in a more reliable and efficient manner. To this end, a suite of test problems that illustratemore » these convergence problems is provided to facilitate diagnosis and development of an improved convergence strategy. The attached files are being transmitted to you describing the test problem and proposed resolution.« less

  13. Ground vibration test of the laminar flow control JStar airplane

    NASA Technical Reports Server (NTRS)

    Kehoe, M. W.; Cazier, F. W., Jr.; Ellison, J. F.

    1985-01-01

    A ground vibration test was conducted on a Lockheed JetStar airplane that had been modified for the purpose of conducting laminar flow control experiments. The test was performed prior to initial flight flutter tests. Both sine-dwell and single-point-random excitation methods were used. The data presented include frequency response functions and a comparison of mode frequencies and mode shapes from both methods.

  14. Fatty Acids Regulate Germline Sex Determination through ACS-4-Dependent Myristoylation.

    PubMed

    Tang, Hongyun; Han, Min

    2017-04-20

    Fat metabolism has been linked to fertility and reproductive adaptation in animals and humans, and environmental sex determination potentially plays a role in the process. To investigate the impact of fatty acids (FA) on sex determination and reproductive development, we examined and observed an impact of FA synthesis and mobilization by lipolysis in somatic tissues on oocyte fate in Caenorhabditis elegans. The subsequent genetic analysis identified ACS-4, an acyl-CoA synthetase and its FA-CoA product, as key germline factors that mediate the role of FA in promoting oocyte fate through protein myristoylation. Further tests indicated that ACS-4-dependent protein myristoylation perceives and translates the FA level into regulatory cues that modulate the activities of MPK-1/MAPK and key factors in the germline sex-determination pathway. These findings, including a similar role of ACS-4 in a male/female species, uncover a likely conserved mechanism by which FA, an environmental factor, regulates sex determination and reproductive development. Copyright © 2017 Elsevier Inc. All rights reserved.

  15. Flow for Exercise Adherence: Testing an Intrinsic Model of Health Behavior

    ERIC Educational Resources Information Center

    Petosa, R. Lingyak; Holtz, Brian

    2013-01-01

    Background: Health behavior theory generally does not include intrinsic motivation as a determinate of health practices. Purpose: The purpose of this study was to test the flow theory of exercise adherence. Flow theory posits that exercise can be intrinsically rewarding if the experiences of self/time transcendence and control/mastery are achieved…

  16. Nanoscale Capillary Flows in Alumina: Testing the Limits of Classical Theory.

    PubMed

    Lei, Wenwen; McKenzie, David R

    2016-07-21

    Anodic aluminum oxide (AAO) membranes have well-formed cylindrical channels, as small as 10 nm in diameter, in a close packed hexagonal array. The channels in AAO membranes simulate very small leaks that may be present for example in an aluminum oxide device encapsulation. The 10 nm alumina channel is the smallest that has been studied to date for its moisture flow properties and provides a stringent test of classical capillary theory. We measure the rate at which moisture penetrates channels with diameters in the range of 10 to 120 nm with moist air present at 1 atm on one side and dry air at the same total pressure on the other. We extend classical theory for water leak rates at high humidities by allowing for variable meniscus curvature at the entrance and show that the extended theory explains why the flow increases greatly when capillary filling occurs and enables the contact angle to be determined. At low humidities our measurements for air-filled channels agree well with theory for the interdiffusive flow of water vapor in air. The flow rate of water-filled channels is one order of magnitude less than expected from classical capillary filling theory and is coincidentally equal to the helium flow rate, validating the use of helium leak testing for evaluating moisture flows in aluminum oxide leaks.

  17. Flow testing of the Newberry 2 research drillhole, Newberry volcano, Oregon

    USGS Publications Warehouse

    Ingebritsen, S.E.; Carothers, W.W.; Mariner, R.H.; Gudmundsson, J.S.; Sammel, E.A.

    1986-01-01

    A 20 hour flow test of the Newberry 2 research drillhole at Newberry Volcano produced about 33,000 kilograms of fluid. The flow rate declined from about 0.8 kilograms per sec to less than 0.3 kilograms per sec during the course of the test. The mass ratio of liquid water to vapor was about 3:2 at the separator and stayed fairly constant throughout the test. The vapor phase was about half steam and half CO2 by weight. The average enthalpy of the steam/water mixture at the separator was about 1 ,200 kilojoules per kilogram. Because of the low flow rate and the large temperature gradient into the surrounding rocks, heat loss from the wellbore was high; a simple conductive model gives overall losses of about 1,200 kilojoules per kilogram of H2O produced. The actual heat loss may have been even higher due to convective effects, and it is likely that the fluid entering the bottom of the wellbore was largely or entirely steam and CO2. (Author 's abstract)

  18. Hot-Film and Hot-Wire Anemometry for a Boundary Layer Active Flow Control Test

    NASA Technical Reports Server (NTRS)

    Lenahan, Keven C.; Schatzman, David M.; Wilson, Jacob Samuel

    2013-01-01

    Unsteady active flow control (AFC) has been used experimentally for many years to minimize bluff-body drag. This technology could significantly improve performance of rotorcraft by cleaning up flow separation. It is important, then, that new actuator technologies be studied for application to future vehicles. A boundary layer wind tunnel was constructed with a 1ft-x-3ft test section and unsteady measurement instrumentation to study how AFC manipulates the boundary layer to overcome adverse pressure gradients and flow separation. This unsteady flow control research requires unsteady measurement methods. In order to measure the boundary layer characteristics, both hot-wire and hot-film Constant Temperature Anemometry is used. A hot-wire probe is mounted in the flow to measure velocity while a hot-film array lays on the test surface to measure skin friction. Hot-film sensors are connected to an anemometer, a Wheatstone bridge circuit with an output that corresponds to the dynamic flow response. From this output, the time varying flow field, turbulence, and flow reversal can be characterized. Tuning the anemometers requires a fan test on the hot-film sensors to adjust each output. This is a delicate process as several variables drastically affect the data, including control resistance, signal input, trim, and gain settings.

  19. The ac power line protection for an IEEE 587 Class B environment

    NASA Technical Reports Server (NTRS)

    Roehr, W. D.; Clark, O. M.

    1984-01-01

    The 587B series of protectors are unique, low clamping voltage transient suppressors to protect ac-powered equipment from the 6000V peak open-circuit voltage and 3000A short circuit current as defined in IEEE standard 587 for Category B transients. The devices, which incorporate multiple-stage solid-state protector components, were specifically designed to operate under multiple exposures to maximum threat levels in this severe environment. The output voltage peaks are limited to 350V under maximum threat conditions for a 120V ac power line, thus providing adequate protection to vulnerable electronic equipment. The principle of operation and test performance data is discussed.

  20. ACS and STEMI treatment: gender-related issues.

    PubMed

    Chieffo, Alaide; Buchanan, Gill Louise; Mauri, Fina; Mehilli, Julinda; Vaquerizo, Beatriz; Moynagh, Anouska; Mehran, Roxana; Morice, Marie-Claude

    2012-08-01

    Cardiovascular disease is the leading cause of death amongst women, with acute coronary syndromes (ACS) representing a significant proportion. It has been reported that in women presenting with ACS there is underdiagnosis and consequent undertreatment leading to an increase in hospital and long-term mortality. Several factors have to be taken into account, including lack of awareness both at patient and at physician level. Women are generally not aware of the cardiovascular risk and symptoms, often atypical, and therefore wait longer to seek medical attention. In addition, physicians often underestimate the risk of ACS in women leading to a further delay in accurate diagnosis and timely appropriate treatment, including cardiac catheterisation and primary percutaneous coronary intervention, with consequent delayed revascularisation times. It has been acknowledged by the European Society of Cardiology that gender disparities do exist, with a Class I, Level of Evidence B recommendation that both genders should be treated in the same way when presenting with ACS. However, there is still a lack of awareness and the mission of Women in Innovation, in association with Stent for Life, is to change the perception of women with ACS and to achieve prompt diagnosis and treatment.

  1. Electrostatic coalescence system with independent AC and DC hydrophilic electrodes

    DOEpatents

    Hovarongkura, A. David; Henry, Jr., Joseph D.

    1981-01-01

    An improved electrostatic coalescence system is provided in which independent AC and DC hydrophilic electrodes are employed to provide more complete dehydration of an oil emulsion. The AC field is produced between an AC electrode array and the water-oil interface wherein the AC electrode array is positioned parallel to the interface which acts as a grounded electrode. The emulsion is introduced into the AC field in an evenly distributed manner at the interface. The AC field promotes drop-drop and drop-interface coalescence of the water phase in the entering emulsion. The continuous oil phase passes upward through the perforated AC electrode array and enters a strong DC field produced between closely spaced DC electrodes in which small dispersed droplets of water entrained in the continuous phase are removed primarily by collection at hydrophilic DC electrodes. Large droplets of water collected by the electrodes migrate downward through the AC electrode array to the interface. All phase separation mechanisms are utilized to accomplish more complete phase separation.

  2. Flow tests of a single fuel element coolant channel for a compact fast reactor for space power

    NASA Technical Reports Server (NTRS)

    Springborn, R. H.

    1971-01-01

    Water flow tests were conducted on a single-fuel-element cooling channel for a nuclear concept to be used for space power. The tests established a method for measuring coolant flow rate which is applicable to water flow testing of a complete mockup of the reference reactor. The inlet plenum-to-outlet plenum pressure drop, which approximates the overall core pressure drop, was measured and correlated with flow rate. This information can be used for reactor coolant flow and heat transfer calculations. An analytical study of the flow characteristics was also conducted.

  3. AC and DC electrical properties of graphene nanoplatelets reinforced epoxy syntactic foam

    NASA Astrophysics Data System (ADS)

    Zegeye, Ephraim; Wicker, Scott; Woldesenbet, Eyassu

    2018-04-01

    Benefits of employing graphene nanopletlates (GNPLs) in composite structures include mechanical as well as multifunctional properties. Understanding the impedance behavior of GNPLs reinforced syntactic foams may open new applications for syntactic foam composites. In this work, GNPLs reinforced syntactic foams were fabricated and tested for DC and AC electrical properties. Four sets of syntactic foam samples containing 0, 0.1, 0.3, and 0.5 vol% of GNPLs were fabricated and tested. Significant increase in conductivity of syntactic foams due to the addition of GNPLs was noted. AC impedance measurements indicated that the GNPLs syntactic foams become frequency dependent as the volume fraction of GNPLs increases. With addition of GNPLs, the characteristic of the syntactic foams are also observed to transition from dominant capacitive to dominant resistive behavior. This work was carried out at Southern University, Mechanical Engineering Department, Baton Rouge, LA 70802, United States of America.

  4. Effect of turbulent flow on an atmospheric-pressure AC powered gliding arc discharge

    NASA Astrophysics Data System (ADS)

    Kong, Chengdong; Gao, Jinlong; Zhu, Jiajian; Ehn, Andreas; Aldén, Marcus; Li, Zhongshan

    2018-06-01

    A high-power gliding arc (GA) discharge was generated in a turbulent air flow driven by a 35 kHz alternating current electric power supply. The effects of the flow rate on the characteristics of the GA discharge were investigated using combined optical and electrical diagnostics. Phenomenologically, the GA discharge exhibits two types of discharge, i.e., glow type and spark type, depending on the flow rates and input powers. The glow-type discharge, which has peak currents of hundreds of milliamperes, is sustained at low flow rates. The spark-type discharge, which is characterized by a sharp current spike of several amperes with duration of less than 1 μs, occurs more frequently as the flow rate increases. Higher input power can suppress spark-type discharges in moderate turbulence, but this effect becomes weak under high turbulent conditions. Physically, the transition between glow- and spark-type is initiated by the short cutting events and the local re-ignition events. Short cutting events occur owing to the twisting, wrinkling, and stretching of the plasma columns that are governed by the relatively large vortexes in the flow. Local re-ignition events, which are defined as re-ignition along plasma columns, are detected in strong turbulence due to increment of the impedance of the plasma column and consequently the internal electric field strength. It is suggested that the vortexes with length scales smaller than the size of the plasma can penetrate into the plasma column and promote mixing with surroundings to accelerate the energy dissipation. Therefore, the turbulent flow influences the GA discharges by ruling the short cutting events with relatively large vortexes and the local re-ignition events with small vortexes.

  5. Use of an AC/DC/AC Electrochemical Technique to Assess the Durability of Protection Systems for Magnesium Alloys

    NASA Astrophysics Data System (ADS)

    Song, Sen; McCune, Robert C.; Shen, Weidian; Wang, Yar-Ming

    One task under the U.S. Automotive Materials Partnership (USAMP) "Magnesium Front End Research and Development" (MFERD) Project has been the evaluation of methodologies for the assessment of protective capability for a variety of proposed protection schemes for this hypothesized multi-material, articulated structure. Techniques which consider the entire protection system, including both pretreatments and topcoats are of interest. In recent years, an adaptation of the classical electrochemical impedance spectroscopy (EIS) approach using an intermediate cathodic DC polarization step (viz. AC/DC/AC) has been employed to accelerate breakdown of coating protection, specifically at the polymer-pretreatment interface. This work reports outcomes of studies to employ the AC/DC/AC approach for comparison of protective coatings to various magnesium alloys considered for front end structures. In at least one instance, the protective coating system breakdown could be attributed to the poorer intrinsic corrosion resistance of the sheet material (AZ31) relative to die-cast AM60B.

  6. Should fee-for-service be for all guideline-advocated acute coronary syndrome (ACS) care? Observations from the Snapshot ACS study.

    PubMed

    Briffa, Thomas G; Hammett, Christopher J; Cross, David B; Macisaac, Andrew I; Rankin, James M; Board, Neville; Carr, Bridie; Hyun, Karice K; French, John; Brieger, David B; Chew, Derek P

    2015-09-01

    The aim of the present study was to explore the association of health insurance status on the provision of guideline-advocated acute coronary syndrome (ACS) care in Australia. Consecutive hospitalisations of suspected ACS from 14 to 27 May 2012 enrolled in the Snapshot study of Australian and New Zealand patients were evaluated. Descriptive and logistic regression analysis was performed to evaluate the association of patient risk and insurance status with the receipt of care. In all, 3391 patients with suspected ACS from 247 hospitals (23 private) were enrolled in the present study. One-third of patients declared private insurance coverage; of these, 27.9% (304/1088) presented to private facilities. Compared with public patients, privately insured patients were more likely to undergo in-patient echocardiography and receive early angiography; furthermore, in those with a discharge diagnosis of ACS, there was a higher rate of revascularisation (P < 0.001). Each of these attracts potential fee-for-service. In contrast, proportionately fewer privately insured ACS patients were discharged on selected guideline therapies and were referred to a secondary prevention program (P = 0.056), neither of which directly attracts a fee. Typically, as GRACE (the Global Registry of Acute Coronary Events) risk score rose, so did the level of ACS care; however, propensity-adjusted analyses showed lower in-hospital adverse events among the insured group (odds ratio 0.68; 95% confidence interval 0.52-0.88; P = 0.004). Fee-for-service reimbursement may explain differences in the provision of selected guideline-advocated components of ACS care between privately insured and public patients.

  7. Cadmium-induced ethylene production and responses in Arabidopsis thaliana rely on ACS2 and ACS6 gene expression

    PubMed Central

    2014-01-01

    Background Anthropogenic activities cause metal pollution worldwide. Plants can absorb and accumulate these metals through their root system, inducing stress as a result of excess metal concentrations inside the plant. Ethylene is a regulator of multiple plant processes, and is affected by many biotic and abiotic stresses. Increased ethylene levels have been observed after exposure to excess metals but it remains unclear how the increased ethylene levels are achieved at the molecular level. In this study, the effects of cadmium (Cd) exposure on the production of ethylene and its precursor 1-aminocyclopropane-1-carboxylic acid (ACC), and on the expression of the ACC Synthase (ACS) and ACC Oxidase (ACO) multigene families were investigated in Arabidopsis thaliana. Results Increased ethylene release after Cd exposure was directly measurable in a system using rockwool-cultivated plants; enhanced levels of the ethylene precursor ACC together with higher mRNA levels of ethylene responsive genes: ACO2, ETR2 and ERF1 also indicated increased ethylene production in hydroponic culture. Regarding underlying mechanisms, it was found that the transcript levels of ACO2 and ACO4, the most abundantly expressed members of the ACO multigene family, were increased upon Cd exposure. ACC synthesis is the rate-limiting step in ethylene biosynthesis, and transcript levels of both ACS2 and ACS6 showed the highest increase and became the most abundant isoforms after Cd exposure, suggesting their importance in the Cd-induced increase of ethylene production. Conclusions Cadmium induced the biosynthesis of ACC and ethylene in Arabidopsis thaliana plants mainly via the increased expression of ACS2 and ACS6. This was confirmed in the acs2-1acs6-1 double knockout mutants, which showed a decreased ethylene production, positively affecting leaf biomass and resulting in a delayed induction of ethylene responsive gene expressions without significant differences in Cd contents between wild-type and

  8. AUTOMOTIVE DIESEL MAINTENANCE 2. UNIT XVII, LEARNING ABOUT AC GENERATOR (ALTERNATOR) PRINCIPLES (PART II).

    ERIC Educational Resources Information Center

    Minnesota State Dept. of Education, St. Paul. Div. of Vocational and Technical Education.

    THIS MODULE OF A 25-MODULE COURSE IS DESIGNED TO DEVELOP AN UNDERSTANDING OF THE OPERATING PRINCIPLES AND THE SERVICING AND TESTING PROCEDURES FOR ALTERNATING CURRENT (AC) GENERATORS AND REGULATORS USED ON DIESEL POWERED EQUIPMENT. TOPICS ARE REVIEW OF ALTERNATOR PRINCIPLES, ALTERNATOR SERVICING AND TESTING, ALTERNATOR REGULATOR OPERATING…

  9. Continuous-flow stirred-tank reactor 20-L demonstration test: Final report

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

    Lee, D.D.; Collins, J.L.

    One of the proposed methods of removing the cesium, strontium, and transuranics from the radioactive waste storage tanks at Savannah River is the small-tank tetraphenylborate (TPB) precipitation process. A two-reactor-in-series (15-L working volume each) continuous-flow stirred-tank reactor (CSTR) system was designed, constructed, and installed in a hot cell to test the Savannah River process. The system also includes two cross-flow filtration systems to concentrate and wash the slurry produced in the process, which contains the bulk of radioactivity from the supernatant processed through the system. Installation, operational readiness reviews, and system preparation and testing were completed. The first test usingmore » the filtration systems, two CSTRs, and the slurry concentration system was conducted over a 61-h period with design removal of Cs, Sr, and U achieved. With the successful completion of Test 1a, the following tests, 1b and 1c, were not required.« less

  10. From Ion Current to Electroosmotic Flow Rectification in Asymmetric Nanopore Membranes

    PubMed Central

    Wu, Xiaojian

    2017-01-01

    Asymmetrically shaped nanopores have been shown to rectify the ionic current flowing through pores in a fashion similar to a p-n junction in a solid-state diode. Such asymmetric nanopores include conical pores in polymeric membranes and pyramidal pores in mica membranes. We review here both theoretical and experimental aspects of this ion current rectification phenomenon. A simple intuitive model for rectification, stemming from previously published more quantitative models, is discussed. We also review experimental results on controlling the extent and sign of rectification. It was shown that ion current rectification produces a related rectification of electroosmotic flow (EOF) through asymmetric pore membranes. We review results that show how to measure and modulate this EOF rectification phenomenon. Finally, EOF rectification led to the development of an electroosmotic pump that works under alternating current (AC), as opposed to the currently available direct current EOF pumps. Experimental results on AC EOF rectification are reviewed, and advantages of using AC to drive EOF are discussed. PMID:29240676

  11. From Ion Current to Electroosmotic Flow Rectification in Asymmetric Nanopore Membranes.

    PubMed

    Experton, Juliette; Wu, Xiaojian; Martin, Charles R

    2017-12-14

    Asymmetrically shaped nanopores have been shown to rectify the ionic current flowing through pores in a fashion similar to a p-n junction in a solid-state diode. Such asymmetric nanopores include conical pores in polymeric membranes and pyramidal pores in mica membranes. We review here both theoretical and experimental aspects of this ion current rectification phenomenon. A simple intuitive model for rectification, stemming from previously published more quantitative models, is discussed. We also review experimental results on controlling the extent and sign of rectification. It was shown that ion current rectification produces a related rectification of electroosmotic flow (EOF) through asymmetric pore membranes. We review results that show how to measure and modulate this EOF rectification phenomenon. Finally, EOF rectification led to the development of an electroosmotic pump that works under alternating current (AC), as opposed to the currently available direct current EOF pumps. Experimental results on AC EOF rectification are reviewed, and advantages of using AC to drive EOF are discussed.

  12. Modelling ac ripple currents in HTS coated conductors

    NASA Astrophysics Data System (ADS)

    Xu, Zhihan; Grilli, Francesco

    2015-10-01

    Dc transmission using high temperature superconducting (HTS) coated conductors (CCs) offers a promising solution to the globally growing demand for effective, reliable and economic transmission of green energy up to the gigawatt level over very long distances. The credible estimation of the losses and thereby the heat dissipation involved, where ac ripples (introduced in rectification/ac-dc conversion) are viewed as a potential source of notable contribution, is highly essential for the rational design of practical HTS dc transmission cables and corresponding cryogenic systems to fulfil this demand. Here we report a targeted modelling study into the ac losses in a HTS CC subject to dc and ac ripple currents simultaneously, by solving Maxwell’s equations using the finite element method (FEM) in the commercial software package COMSOL. It is observed that the instantaneous loss exhibits only one peak per cycle in the HTS CC subject to sinusoidal ripples, given that the amplitude of the ac ripples is smaller than approximately 20% of that of the dc current. This is a distinct contrast to the usual observation of two peaks per cycle in a HTS CC subject to ac currents only. The unique mechanism is also revealed, which is directly associated with the finding that, around any local minima of the applied ac ripples, the critical state of -J c is never reached at the edges of the HTS CC, as it should be according to the Bean model. When running further into the longer term, it is discovered that the ac ripple loss of the HTS CC in full-wave rectification decays monotonically, at a speed which is found to be insensitive to the frequency of the applied ripples within our targeted situations, to a relatively low level of approximately 1.38 × 10-4 W m-1 in around 1.7 s. Comparison between this level and other typical loss contributions in a HTS dc cable implies that ac ripple currents in HTS CCs should only be considered as a minor source of dissipation in superconducting dc

  13. ACS Data Handbook v.6.0

    NASA Astrophysics Data System (ADS)

    Gonzaga, S.; et al.

    2011-03-01

    ACS was designed to provide a deep, wide-field survey capability from the visible to near-IR using the Wide Field Camera (WFC), high resolution imaging from the near-UV to near-IR with the now-defunct High Resolution Camera (HRC), and solar-blind far-UV imaging using the Solar Blind Camera (SBC). The discovery efficiency of ACS's Wide Field Channel (i.e., the product of WFC's field of view and throughput) is 10 times greater than that of WFPC2. The failure of ACS's CCD electronics in January 2007 brought a temporary halt to CCD imaging until Servicing Mission 4 in May 2009, when WFC functionality was restored. Unfortunately, the high-resolution optical imaging capability of HRC was not recovered.

  14. Functional Regulation of an Autographa californica Nucleopolyhedrovirus-Encoded MicroRNA, AcMNPV-miR-1, in Baculovirus Replication

    PubMed Central

    Zhu, Mengxiao; Deng, Riqiang

    2016-01-01

    ABSTRACT An Autographa californica nucleopolyhedrovirus-encoded microRNA (miRNA), AcMNPV-miR-1, downregulates the ac94 gene, reducing the production of infectious budded virions and accelerating the formation of occlusion-derived virions. In the current study, four viruses that constitutively overexpress AcMNPV-miR-1 were constructed to further explore the function of the miRNA. In addition to the ac94 gene, two new viral gene targets (ac18 and ac95) of AcMNPV-miR-1 were identified, and the possible interacting proteins were verified and tested. In the context of AcMNPV-miR-1 overexpression, ac18 was slightly upregulated, and ac95 was downregulated. Several interacting proteins were identified, and a functional pathway for AcMNPV-miR-1 was deduced. AcMNPV-miR-1 overexpression decreased budded virus infectivity, reduced viral DNA replication, accelerated polyhedron formation, and promoted viral infection efficiency in Trichoplusia ni larvae, suggesting that AcMNPV-miR-1 restrains virus infection of cells but facilitates virus infection of larvae. IMPORTANCE Recently, microRNAs (miRNAs) have been widely reported as moderators or regulators of mammalian cellular processes, especially disease-related pathways in humans. However, the roles played by miRNAs encoded by baculoviruses, which infect numerous beneficial insects and agricultural pests, have rarely been described. To explore the actions of virus-encoded miRNAs, we investigated an miRNA encoded by Autographa californica nucleopolyhedrovirus (AcMNPV-miR-1). We previously identified this miRNA through the exogenous addition of AcMNPV-miR-1 mimics. In the current study, we constitutively overexpressed AcMNPV-miR-1 and analyzed the resultant effects to more comprehensively assess what is indeed the function of this miRNA during viral infection. In addition, we widely explored the target genes for the miRNA in the viral and host genomes and proposed a possible functional network for AcMNPV-miR-1, which provides a

  15. Longitudinal modelling of theory-based depressive vulnerabilities, depression trajectories and poor outcomes post-ACS.

    PubMed

    Keegan, Conor; Conroy, Ronán; Doyle, Frank

    2016-02-01

    Depression is associated with increased mortality in patients with acute coronary syndrome (ACS). However, little is known about the theoretical causes of depression trajectories post-ACS, and whether these trajectories predict subsequent morbidity/mortality. We tested a longitudinal model of depressive vulnerabilities, trajectories and mortality. A prospective observational study of 374 ACS patients was conducted. Participants completed questionnaires on theoretical vulnerabilities (interpersonal life events, reinforcing events, cognitive distortions, and Type D personality) during hospitalisation and depression at baseline and 3, 6 and 12 months post-hospitalisation. Latent class analysis determined trajectories of depression. Path analysis was used to test relationships among vulnerabilities, depression trajectories and outcomes (combination of 1-year morbidity and 7-year mortality). Vulnerabilities independently predicted persistent and subthreshold depression trajectory categories, with effect sizes significantly highest for persistent depression. Both subthreshold and persistent depression trajectories were significant predictors of morbidity/mortality (e.g. persistent depression OR=2.4, 95% CI=1.8-3.1, relative to never depressed). Causality cannot be inferred from these associations. We had no measures of history of depression or treatments, which may affect associations. Theoretical vulnerabilities predicted depression trajectories, which in turn predicted increased morbidity/mortality, demonstrating for the first time a potential longitudinal chain of events post-ACS. This longitudinal model has important practical implications as clinicians can use vulnerability measures to identify those at most risk of poor outcomes. Copyright © 2015. Published by Elsevier B.V.

  16. Flow visualization methods for field test verification of CFD analysis of an open gloveport

    DOE PAGES

    Strons, Philip; Bailey, James L.

    2017-01-01

    Anemometer readings alone cannot provide a complete picture of air flow patterns at an open gloveport. Having a means to visualize air flow for field tests in general provides greater insight by indicating direction in addition to the magnitude of the air flow velocities in the region of interest. Furthermore, flow visualization is essential for Computational Fluid Dynamics (CFD) verification, where important modeling assumptions play a significant role in analyzing the chaotic nature of low-velocity air flow. A good example is shown Figure 1, where an unexpected vortex pattern occurred during a field test that could not have been measuredmore » relying only on anemometer readings. Here by, observing and measuring the patterns of the smoke flowing into the gloveport allowed the CFD model to be appropriately updated to match the actual flow velocities in both magnitude and direction.« less

  17. ACS-Hach Programs: Supporting Excellence in High School Chemistry Teaching

    NASA Astrophysics Data System (ADS)

    Taylor, Terri

    2009-05-01

    In January 2009, the ACS received a gift of approximately $33 million from the Hach Scientific Foundation, the largest gift in the society's 133-year history. The foundation's programs will be continued by the ACS and will complement pre-existing ACS resources that support high school chemistry teaching. Three activities serve as the pillars of the ACS-Hach programs—the High School Chemistry Grant Program, the Second Career Teacher Scholarship Program, and the Land Grant University Scholars Program. Collectively, the ACS-Hach programs support high school chemistry teaching and learning by responding to the needs of both in-service and pre-service secondary teachers. The goals of each of the ACS-Hach programs align well with the ACS Mission—to advance the broader chemistry enterprise and its practitioners for the benefit of Earth and its people.

  18. ACS Presents Science Education Report to Congress.

    ERIC Educational Resources Information Center

    Krieger, James

    1989-01-01

    Discusses an American Chemical Society (ACS)'s report on science education which is a synthesis of a series of policies developed by ACS. Summarizes recommendations in four areas: elementary teacher education; pre-high school curricula; university research funding; and underrepresented populations. (YP)

  19. AC/DC Power Systems with Applications for future Lunar/Mars base and Crew Exploration Vehicle

    NASA Technical Reports Server (NTRS)

    Chowdhury, Badrul H.

    2005-01-01

    redundancies and including emergency generators on both ac and dc sides is proposed. The generation frequency is 400 Hz mostly because of the technology maturity at this frequency in the aerospace industry. Power will be distributed to several ac load distribution buses through solid state variable speed, constant frequency converters on the ac side. A segmented dc ring bus supplied from ac/dc converters and with the capability of connecting/disconnecting the segments will supply power to multiple de load distribution buses. The system will have the capability of reverse flow from dc to ac side in the case of an extreme emergency on the main ac generation side.

  20. Fabrication and test of a space power boiler feed electromagnetic pump. 3: Endurance and final performance tests

    NASA Technical Reports Server (NTRS)

    Powell, A. H.; Amos, J. C.

    1972-01-01

    A three-phase helical induction electromagnetic pump designed for the boiler feed pump of a potassium Rankine cycle space power system was developed and built. It was mounted in a liquid metal test loop and successfully tested over a range of potassium temperatures from 900 to 1400 F, flow rates from 0.75 to 4.85 lb/sec, developed pressures up to 340 psi, net positive suction head from 1 to 22 psi, and NaK coolant temperatures from 800 to 950 F. Maximum efficiency at design point conditions of 3.25 lb/sec flow rate, 240 psi developed head, 1000 F potassium inlet temperature, and 800 F NaK coolant inlet temperature was 16.3 percent. After the performance tests the pump was operated without any difficulty at design point for 10,000 hours, and then a limited number of repeat performance tests were made. There was no appreciable change in pump performance after 10,000 hours of operation. A supplementary series of tests using the quasi-square wave power output of a dc to three-phase ac inverter showed that the pump would operate without difficulty at a frequency as low as 25 Hz, with little loss in efficiency.

  1. A dry-cooled AC quantum voltmeter

    NASA Astrophysics Data System (ADS)

    Schubert, M.; Starkloff, M.; Peiselt, K.; Anders, S.; Knipper, R.; Lee, J.; Behr, R.; Palafox, L.; Böck, A. C.; Schaidhammer, L.; Fleischmann, P. M.; Meyer, H.-G.

    2016-10-01

    The paper describes a dry-cooled AC quantum voltmeter system operated up to kilohertz frequencies and 7 V rms. A 10 V programmable Josephson voltage standard (PJVS) array was installed on a pulse tube cooler (PTC) driven with a 4 kW air-cooled compressor. The operating margins at 70 GHz frequencies were investigated in detail and found to exceed 1 mA Shapiro step width. A key factor for the successful chip operation was the low on-chip power consumption of 65 mW in total. A thermal interface between PJVS chip and PTC cold stage was used to avoid a significant chip overheating. By installing the cryocooled PJVS array into an AC quantum voltmeter setup, several calibration measurements of dc standards and calibrator ac voltages up to 2 kHz frequencies were carried out to demonstrate the full functionality. The results are discussed and compared to systems with standard liquid helium cooling. For dc voltages, a direct comparison measurement between the dry-cooled AC quantum voltmeter and a liquid-helium based 10 V PJVS shows an agreement better than 1 part in 1010.

  2. Nitrate Contamination in the groundwater of the Lake Acıgöl Basin, SW Turkey

    NASA Astrophysics Data System (ADS)

    Karaman, Muhittin; Budakoǧlu, Murat; Taşdelen, Suat

    2017-04-01

    The lacustrine Acıgöl basin, formed as an extensional half-graben, hosts various bodies of water, such as cold-hot springs, lakes, streams, and wells. The hydrologically closed basin contains a hypersaline lake (Lake Acıgöl) located in the southern part of the basin. The brackish springs and deep waters discharged along the Acıgöl fault zone in the southern part of the basin feed the hypersaline lake. Groundwater is used as drinking, irrigation, and domestic water in the closed Acıgöl Basin. Groundwater flows into the hypersaline lake from the highland. The Acıgöl basin hosts large plains (Hambat, Başmakçı, and Evciler). Waters in agricultural areas contain high amounts of nitrate; groundwater samples in agricultural areas contain nitrate levels higher than 10 mg/L. Nitrate concentrations in the groundwater samples varied from 0 to 487 mg/L (n=165); 25.4 % of the groundwater samples from the basin had nitrate concentrations above 10 mg/L (the WHO drinking guideline) and 52.2% of the groundwater samples from the basin had nitrate concentrations above 3.0 mg/L, and these high values were regarded as the result of human activity. The highest nitrate values were measured in the Hambat plain (480 and 100 mg/L) and Yirce Pinari spring (447 mg/L), which discharges along the Acıgöl fault zone in the southern part of the basin. The average multi-temporal nitrate concentration of the Yirce Pınarı spring was 3.3 mg/L. Extreme nitrate values were measured in the Yirce Pınarı spring during periods when sheep wool was washed (human activity). The lowest nitrate concentrations were observed in some springs that discharged along the Acıgöl fault zone in the southern part of the basin. Nitrate was not detected in deep groundwater discharged along the Acıgöl fault zone. Nitrate concentrations in deep groundwater and some springs discharged along the Acıgöl fault zone and those feeding the hypersaline lake were significantly affected by redox conditions

  3. Flow and Heat Transfer Tests in New Loop at 2757 kPa (400 psi)

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

    Woloshun, Keith Albert

    2016-06-13

    A helium flow and heat transfer experiment has been designed for the new helium flow loop facility at LANL. This new facility is centered on an Aerzen GM 12.4 Root’s blower, selected for operation at higher pressure, up to 2757 kPa, and mass flow rate, up to 400 g/s. This replaces the previous Tuthill PD plus 3206 blower and loop limited to 2067 kPa (300 psi) and 100 g/s. The resistively heated test piece is comprised of 7 electric heaters with embedded thermocouples. The plant design for the Mo100 to Mo99 targets requires sharp bends and geometry changes in themore » helium flow tube immediately before and after the target. An idealized fully developed flow configuration with straight entry and exit will be tested and compared with an option that employs rectangular tubing to make the bend at a radius consistent with and practical for the actual plant design. The current plant design, with circular tubing and a sudden contraction to rectangular just prior to target entrance, will also be tested. This requires some modification of the test piece, as described in the report.« less

  4. Methods to Enhance Laser Speckle Imaging of High-Flow and Low-Flow Vasculature

    PubMed Central

    Choi, Bernard; Ringold, Tyson L.; Kim, Jeehyun

    2012-01-01

    The objective of this paper is to present two methods to extend the response range of laser speckle imaging (LSI). We report on the use of two methods (image exposure time control and magnetomotive actuation of exogenous contrast agents) to enhance characterization of high- and low-flow vasculature, respectively. With an exposure time of 10 and 0.01 ms, the linear response range extended to 10 and 280 mm/s, respectively. With application of an AC magnetic field to a solution of stagnant SPIO particles, an apparent increase of ~3× in speckle flow index was induced. PMID:19964103

  5. Flow cytometric osmotic fragility test and eosin-5'-maleimide dye-binding tests are better than conventional osmotic fragility tests for the diagnosis of hereditary spherocytosis.

    PubMed

    Arora, R D; Dass, J; Maydeo, S; Arya, V; Radhakrishnan, N; Sachdeva, A; Kotwal, J; Bhargava, M

    2018-06-01

    Hereditary spherocytosis (HS) is the most common inherited hemolytic anemia with heterogeneous clinico-laboratory manifestations. We evaluated the flow-cytometric tests: eosin-5'-maleimide (EMA) and flow-cytometric osmotic fragility test (FOFT) and the conventional osmotic fragility tests (OFT) for the diagnosis of hereditary spherocytosis (HS). One hundred two suspected HS patients underwent EMA, FOFT, incubated OFT (IOFT), and room temperature OFT (RT-OFT). In addition, 10 cases of immune hemolytic anemia (IHA) were included, and performance of the above 4 tests was evaluated. For EMA and FOFT, 5 normal controls were assessed together with the patients and cutoffs were calculated using receiver-operator-characteristics curve (ROC) analysis. The best cutoff for %EMA decrease was 12.5%, and for FOFT, %residual red cells (%RRC) was 25.6%. The sensitivity and specificity of RT-OFT was 62.06% and 86.3%, respectively, while that of IOFT was 79.31% and 87.67%, respectively. Both flow cytometric tests performed better. Sensitivity and specificity of EMA was 86.2% and 93.9% respectively, and that of FOFT was 96.6% and 98.63%, respectively. The combination of the FOFT with IOFT or EMA dye-binding test yields a sensitivity of 100%, but with EMA, it had a higher specificity. Hb/MCHC was a predictor of the severity of the disease while %EMA decrease and %RRC did not correlate with severity of the disease. Flow-cytometric osmotic fragility test is the best possible single test followed by EMA for diagnosis of HS. A combination of FOFT and EMA can correctly diagnose 100% patients. These tests are likely to replace conventional OFTs in future. © 2018 John Wiley & Sons Ltd.

  6. Impact of Vascular Hemodynamics on Aortic Stenosis Evaluation: New Insights Into the Pathophysiology of Normal Flow-Small Aortic Valve Area-Low Gradient Pattern.

    PubMed

    Côté, Nancy; Simard, Louis; Zenses, Anne-Sophie; Tastet, Lionel; Shen, Mylène; Clisson, Marine; Clavel, Marie-Annick

    2017-07-07

    About 50% of normal-flow/low-gradient patients (ie, low mean gradient [MG] or peak aortic jet velocity and small aortic valve area) have severe aortic valve calcification as measured by computed tomography. However, they are considered to have moderate aortic stenosis (AS) in current American College of Cardiology/American Heart Association guidelines. The objective was thus to evaluate the effect of hypertension and reduced arterial compliance (rAC) on MG and V peak measurements. Doppler-echocardiography was performed in 4 sheep with experimentally induced severe and critical AS at: (1) normal aortic pressure, (2) during hypertension, and (3) with rAC. Hypertension and rAC induced a substantial decrease in MG/V peak compared with normal stage (both P ≤0.03) despite a stable transvalvular flow ( P >0.16). Hypertension and rAC resulted in a greater reduction of MG in critical (-42%) compared with severe (-35%) AS ( P ˂0.0001). Comprehensive Doppler-echocardiography and computed tomography were performed in 220 AS patients (mean age: 69±13 years; MG 29±18 mm Hg) with normal flow. The population was divided in 3 groups according to the presence of hypertension and rAC. The slope of the linear association between MG/V peak and aortic valve calcification divided by the cross-sectional area of the aortic annulus was significantly reduced in patients with hypertension and/or rAC compared with normotensive/normal AC patients ( P <0.01). Accordingly, patients with normal-flow/low-gradient and severe aortic valve calcification density were more frequent in hypertension and rAC groups compared with the normotensive/normal-AC group (16% and 12% compared with 2%; P =0.03). Hypertension and rAC are associated with a substantial reduction in MG/V peak for similar aortic valve calcification (ie, similar AS anatomic severity), which may lead to underestimation of AS hemodynamic severity. © 2017 The Authors. Published on behalf of the American Heart Association, Inc., by

  7. Serotonergic genes and depressive disorder in acute coronary syndrome: The Korean depression in ACS (K-DEPACS) study.

    PubMed

    Kim, Jae-Min; Stewart, Robert; Kang, Hee-Ju; Bae, Kyung-Yeol; Kim, Sung-Wan; Shin, Il-Seon; Hong, Young Joon; Ahn, Youngkeun; Jeong, Myung Ho; Park, Sung-Woo; Kim, Young-Hoon; Yoon, Jin-Sang

    2015-06-01

    Genes coding for the serotonergic pathway have been associated with depressive disorders. However, these associations have rarely been tested in acute coronary syndrome (ACS) patients vulnerable to depression. This study aimed to investigate whether polymorphisms of serotonin transporter (5-HTT) and serotonin 2a receptor (5-HTR2a) genes are associated with occurrence of depressive disorder in ACS. 969 patients with recently developed ACS were recruited at baseline, and 711 were followed 1 year thereafter. Depressive disorder was diagnosed according to DSM-IV criteria, and analysed as an outcome at baseline (prevalence), and follow up (incidence and persistence). Genotypes were ascertained for 5-HTTLPR, STin2 VNTR, 5-HTR2a 102T/C, and 5-HTR2a 1438A/G. Logistic regression models were used to investigate associations. The 5-HTTLPR s/s genotype was independently associated with depressive disorder prevalence and persistence following ACS, but no significant associations were found with the other polymorphisms. ACS patients with the 5-HTTLPR s allele are thus potentially susceptible to depressive disorder in the early phase after ACS, and with its persistence over the subsequent year. Copyright © 2015 Elsevier B.V. and ECNP. All rights reserved.

  8. From Beamline to Scanner with 225Ac

    NASA Astrophysics Data System (ADS)

    Robertson, Andrew K. H.; Ramogida, Caterina F.; Kunz, Peter; Rodriguez-Rodriguez, Cristina; Schaffer, Paul; Sossi, Vesna

    2016-09-01

    Due to the high linear energy transfer and short range of alpha-radiation, targeted radiation therapy using alpha-emitting pharmaceuticals that successfully target small disease clusters will kill target cells with limited harm to healthy tissue, potentially treating the most aggressive forms of cancer. As the parent of a decay chain with four alpha- and two beta-decays, 225Ac is a promising candidate for such a treatment. However, this requires retention of the entire decay chain at the target site, preventing the creation of freely circulating alpha-emitters that reduce therapeutic effect and increase toxicity to non-target tissues. Two major challenges to 225Ac pharmaceutical development exist: insufficient global supply, and the difficulty of preventing toxicity by retaining the entire decay chain at the target site. While TRIUMF works towards large-scale (C i amounts) production of 225Ac, we already use our Isotope Separation On-Line facility to provide small (< 1 mCi) quantities for in-house chemistry and imaging research that aims to improve and assess 225Ac radiopharmaceutical targeting. This presentation provides an overview of this research program and the journey of 225Ac from the beamline to the scanner. This research is funded by the Natural Sciences and Engineering Research Council of Canada.

  9. 42 CFR 84.93 - Gas flow test; open-circuit apparatus.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ...) water-column height when full container pressure is applied. (c) Where pressure demand apparatus are tested, the flow will be measured at zero gage pressure in the facepiece. (d) Where apparatus with...

  10. 42 CFR 84.93 - Gas flow test; open-circuit apparatus.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ...) water-column height when full container pressure is applied. (c) Where pressure demand apparatus are tested, the flow will be measured at zero gage pressure in the facepiece. (d) Where apparatus with...

  11. 42 CFR 84.93 - Gas flow test; open-circuit apparatus.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ...) water-column height when full container pressure is applied. (c) Where pressure demand apparatus are tested, the flow will be measured at zero gage pressure in the facepiece. (d) Where apparatus with...

  12. 21 CFR 880.5100 - AC-powered adjustable hospital bed.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false AC-powered adjustable hospital bed. 880.5100... (CONTINUED) MEDICAL DEVICES GENERAL HOSPITAL AND PERSONAL USE DEVICES General Hospital and Personal Use Therapeutic Devices § 880.5100 AC-powered adjustable hospital bed. (a) Identification. An AC-powered...

  13. 21 CFR 880.5100 - AC-powered adjustable hospital bed.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false AC-powered adjustable hospital bed. 880.5100... (CONTINUED) MEDICAL DEVICES GENERAL HOSPITAL AND PERSONAL USE DEVICES General Hospital and Personal Use Therapeutic Devices § 880.5100 AC-powered adjustable hospital bed. (a) Identification. An AC-powered...

  14. 21 CFR 880.5100 - AC-powered adjustable hospital bed.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false AC-powered adjustable hospital bed. 880.5100... (CONTINUED) MEDICAL DEVICES GENERAL HOSPITAL AND PERSONAL USE DEVICES General Hospital and Personal Use Therapeutic Devices § 880.5100 AC-powered adjustable hospital bed. (a) Identification. An AC-powered...

  15. 21 CFR 880.5100 - AC-powered adjustable hospital bed.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false AC-powered adjustable hospital bed. 880.5100... (CONTINUED) MEDICAL DEVICES GENERAL HOSPITAL AND PERSONAL USE DEVICES General Hospital and Personal Use Therapeutic Devices § 880.5100 AC-powered adjustable hospital bed. (a) Identification. An AC-powered...

  16. A Case Study of Wind-PV-Thermal-Bundled AC/DC Power Transmission from a Weak AC Network

    NASA Astrophysics Data System (ADS)

    Xiao, H. W.; Du, W. J.; Wang, H. F.; Song, Y. T.; Wang, Q.; Ding, J.; Chen, D. Z.; Wei, W.

    2017-05-01

    Wind power generation and photovoltaic (PV) power generation bundled with the support by conventional thermal generation enables the generation controllable and more suitable for being sent over to remote load centre which are beneficial for the stability of weak sending end systems. Meanwhile, HVDC for long-distance power transmission is of many significant technique advantages. Hence the effects of wind-PV-thermal-bundled power transmission by AC/DC on power system have become an actively pursued research subject recently. Firstly, this paper introduces the technical merits and difficulties of wind-photovoltaic-thermal bundled power transmission by AC/DC systems in terms of meeting the requirement of large-scale renewable power transmission. Secondly, a system model which contains a weak wind-PV-thermal-bundled sending end system and a receiving end system in together with a parallel AC/DC interconnection transmission system is established. Finally, the significant impacts of several factors which includes the power transmission ratio between the DC and AC line, the distance between the sending end system and receiving end system, the penetration rate of wind power and the sending end system structure on system stability are studied.

  17. 21 CFR 888.1240 - AC-powered dynamometer.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false AC-powered dynamometer. 888.1240 Section 888.1240 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES ORTHOPEDIC DEVICES Diagnostic Devices § 888.1240 AC-powered dynamometer. (a...

  18. 21 CFR 888.1240 - AC-powered dynamometer.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false AC-powered dynamometer. 888.1240 Section 888.1240 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES ORTHOPEDIC DEVICES Diagnostic Devices § 888.1240 AC-powered dynamometer. (a...

  19. 21 CFR 888.1240 - AC-powered dynamometer.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false AC-powered dynamometer. 888.1240 Section 888.1240 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES ORTHOPEDIC DEVICES Diagnostic Devices § 888.1240 AC-powered dynamometer. (a...

  20. 21 CFR 880.5100 - AC-powered adjustable hospital bed.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false AC-powered adjustable hospital bed. 880.5100 Section 880.5100 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES... Therapeutic Devices § 880.5100 AC-powered adjustable hospital bed. (a) Identification. An AC-powered...

  1. Nonlinear AC susceptibility, surface and bulk shielding

    NASA Astrophysics Data System (ADS)

    van der Beek, C. J.; Indenbom, M. V.; D'Anna, G.; Benoit, W.

    1996-02-01

    We calculate the nonlinear AC response of a thin superconducting strip in perpendicular field, shielded by an edge current due to the geometrical barrier. A comparison with the results for infinite samples in parallel field, screened by a surface barrier, and with those for screening by a bulk current in the critical state, shows that the AC response due to a barrier has general features that are independent of geometry, and that are significantly different from those for screening by a bulk current in the critical state. By consequence, the nonlinear (global) AC susceptibility can be used to determine the origin of magnetic irreversibility. A comparison with experiments on a Bi 2Sr 2CaCu 2O 8+δ crystal shows that in this material, the low-frequency AC screening at high temperature is mainly due to the screening by an edge current, and that this is the unique source of the nonlinear magnetic response at temperatures above 40 K.

  2. Compatibility tests of steels in flowing liquid lead-bismuth

    NASA Astrophysics Data System (ADS)

    Barbier, F.; Benamati, G.; Fazio, C.; Rusanov, A.

    2001-06-01

    The behaviour of steels exposed to flowing Pb-55Bi was evaluated. The materials tested are the two austenitic steels AISI 316L and 1.4970, and the six martensitic steels Optifer IVc, T91, Batman 27, Batman 28, EP823 and EM10 which were exposed to flowing Pb-55Bi for 1000, 2000 and 3000 h and at two temperatures (573 and 743 K). The corrosion tests were conducted in the non-isothermal loop of IPPE-Obninsk under a controlled oxygen level (10 -6 wt%). The compatibility study showed that at a lower temperature, a very thin oxide layer (<1 μm) was formed on the steels. At higher temperature, austenitic steels also exhibited a thin oxide layer sufficient to prevent their dissolution in the melt. A thicker oxide, which grew according to a parabolic law, was observed on the surface of the martensitic steels. The oxidation resistance behaviour of the martensitic steels was correlated with their alloying elements.

  3. AC BREAKDOWN IN GASES

    DTIC Science & Technology

    electron- emission (multipactor) region, and (3) the low-frequency region. The breakdown mechanism in each of these regions is explained. An extensive bibliography on AC breakdown in gases is included.

  4. An AC modulated near infrared gain calibration system for a "Violin-Mode" transimpedance amplifier, intended for advanced LIGO suspensions.

    PubMed

    Lockerbie, N A; Tokmakov, K V

    2016-07-01

    The background to this work was a prototype shadow sensor, which was designed for retro-fitting to an advanced LIGO (Laser Interferometer Gravitational wave Observatory) test-mass/mirror suspension, in which a 40 kg test-mass/mirror is suspended by four approximately 600 mm long by 0.4 mm diameter fused-silica suspension fibres. The shadow sensor comprised a LED source of Near InfraRed (NIR) radiation, and a "tall-thin" rectangular silicon photodiode detector, which together were to bracket the fibre under test. The photodiode was positioned so as to be sensitive (primarily) to transverse "Violin-Mode" vibrations of such a fibre, via the oscillatory movement of the shadow cast by the fibre, as this moved across the face of the detector. In this prototype shadow sensing system the photodiode was interfaced to a purpose-built transimpedance amplifier, this having both AC and DC outputs. A quasi-static calibration was made of the sensor's DC responsivity, i.e., incremental rate of change of output voltage versus fibre position, by slowly scanning a fused-silica fibre sample transversely through the illuminating beam. The work reported here concerns the determination of the sensor's more important AC (Violin-Mode) responsivity. Recognition of the correspondence between direct AC modulation of the source, and actual Violin-Mode signals, and of the transformative role of the AC/DC gain ratio for the amplifier, at any modulation frequency, f, resulted in the construction of the AC/DC calibration source described here. A method for determining in practice the transimpedance AC/DC gain ratio of the photodiode and amplifier, using this source, is illustrated by a specific numerical example, and the gain ratio for the prototype sensing system is reported over the frequency range 1 Hz-300 kHz. In fact, a maximum DC responsivity of 1.26 kV.m(-1) was measured using the prototype photodiode sensor and amplifier discussed here. Therefore, the measured AC/DC transimpedance gain

  5. Efficacy of Genetically Modified Bt Toxins Alone and in Combinations Against Pink Bollworm Resistant to Cry1Ac and Cry2Ab

    PubMed Central

    Tabashnik, Bruce E.; Fabrick, Jeffrey A.; Unnithan, Gopalan C.; Yelich, Alex J.; Masson, Luke; Zhang, Jie; Bravo, Alejandra; Soberón, Mario

    2013-01-01

    Evolution of resistance in pests threatens the long-term efficacy of insecticidal proteins from Bacillus thuringiensis (Bt) used in sprays and transgenic crops. Previous work showed that genetically modified Bt toxins Cry1AbMod and Cry1AcMod effectively countered resistance to native Bt toxins Cry1Ab and Cry1Ac in some pests, including pink bollworm (Pectinophora gossypiella). Here we report that Cry1AbMod and Cry1AcMod were also effective against a laboratory-selected strain of pink bollworm resistant to Cry2Ab as well as to Cry1Ab and Cry1Ac. Resistance ratios based on the concentration of toxin killing 50% of larvae for the resistant strain relative to a susceptible strain were 210 for Cry2Ab, 270 for Cry1Ab, and 310 for Cry1Ac, but only 1.6 for Cry1AbMod and 2.1 for Cry1AcMod. To evaluate the interactions among toxins, we tested combinations of Cry1AbMod, Cry1Ac, and Cry2Ab. For both the resistant and susceptible strains, the net results across all concentrations tested showed slight but significant synergism between Cry1AbMod and Cry2Ab, whereas the other combinations of toxins did not show consistent synergism or antagonism. The results suggest that the modified toxins might be useful for controlling populations of pink bollworm resistant to Cry1Ac, Cry2Ab, or both. PMID:24244692

  6. Assessing the allelotypic effect of two aminocyclopropane carboxylic acid synthase-encoding genes MdACS1 and MdACS3a on fruit ethylene production and softening in Malus

    PubMed Central

    Dougherty, Laura; Zhu, Yuandi; Xu, Kenong

    2016-01-01

    Phytohormone ethylene largely determines apple fruit shelf life and storability. Previous studies demonstrated that MdACS1 and MdACS3a, which encode 1-aminocyclopropane-1-carboxylic acid synthases (ACS), are crucial in apple fruit ethylene production. MdACS1 is well-known to be intimately involved in the climacteric ethylene burst in fruit ripening, while MdACS3a has been regarded a main regulator for ethylene production transition from system 1 (during fruit development) to system 2 (during fruit ripening). However, MdACS3a was also shown to have limited roles in initiating the ripening process lately. To better assess their roles, fruit ethylene production and softening were evaluated at five time points during a 20-day post-harvest period in 97 Malus accessions and in 34 progeny from 2 controlled crosses. Allelotyping was accomplished using an existing marker (ACS1) for MdACS1 and two markers (CAPS866 and CAPS870) developed here to specifically detect the two null alleles (ACS3a-G289V and Mdacs3a) of MdACS3a. In total, 952 Malus accessions were allelotyped with the three markers. The major findings included: The effect of MdACS1 was significant on fruit ethylene production and softening while that of MdACS3a was less detectable; allele MdACS1–2 was significantly associated with low ethylene and slow softening; under the same background of the MdACS1 allelotypes, null allele Mdacs3a (not ACS3a-G289V) could confer a significant delay of ethylene peak; alleles MdACS1–2 and Mdacs3a (excluding ACS3a-G289V) were highly enriched in M. domestica and M. hybrid when compared with those in M. sieversii. These findings are of practical implications in developing apples of low and delayed ethylene profiles by utilizing the beneficial alleles MdACS1-2 and Mdacs3a. PMID:27231553

  7. Distribution-Agnostic Stochastic Optimal Power Flow for Distribution Grids: Preprint

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

    Baker, Kyri; Dall'Anese, Emiliano; Summers, Tyler

    2016-09-01

    This paper outlines a data-driven, distributionally robust approach to solve chance-constrained AC optimal power flow problems in distribution networks. Uncertain forecasts for loads and power generated by photovoltaic (PV) systems are considered, with the goal of minimizing PV curtailment while meeting power flow and voltage regulation constraints. A data- driven approach is utilized to develop a distributionally robust conservative convex approximation of the chance-constraints; particularly, the mean and covariance matrix of the forecast errors are updated online, and leveraged to enforce voltage regulation with predetermined probability via Chebyshev-based bounds. By combining an accurate linear approximation of the AC power flowmore » equations with the distributionally robust chance constraint reformulation, the resulting optimization problem becomes convex and computationally tractable.« less

  8. Turbulent and Laminar Flow in Karst Conduits Under Unsteady Flow Conditions: Interpretation of Pumping Tests by Discrete Conduit-Continuum Modeling

    NASA Astrophysics Data System (ADS)

    Giese, M.; Reimann, T.; Bailly-Comte, V.; Maréchal, J.-C.; Sauter, M.; Geyer, T.

    2018-03-01

    Due to the duality in terms of (1) the groundwater flow field and (2) the discharge conditions, flow patterns of karst aquifer systems are complex. Estimated aquifer parameters may differ by several orders of magnitude from local (borehole) to regional (catchment) scale because of the large contrast in hydraulic parameters between matrix and conduit, their heterogeneity and anisotropy. One approach to deal with the scale effect problem in the estimation of hydraulic parameters of karst aquifers is the application of large-scale experiments such as long-term high-abstraction conduit pumping tests, stimulating measurable groundwater drawdown in both, the karst conduit system as well as the fractured matrix. The numerical discrete conduit-continuum modeling approach MODFLOW-2005 Conduit Flow Process Mode 1 (CFPM1) is employed to simulate laminar and nonlaminar conduit flow, induced by large-scale experiments, in combination with Darcian matrix flow. Effects of large-scale experiments were simulated for idealized settings. Subsequently, diagnostic plots and analyses of different fluxes are applied to interpret differences in the simulated conduit drawdown and general flow patterns. The main focus is set on the question to which extent different conduit flow regimes will affect the drawdown in conduit and matrix depending on the hydraulic properties of the conduit system, i.e., conduit diameter and relative roughness. In this context, CFPM1 is applied to investigate the importance of considering turbulent conditions for the simulation of karst conduit flow. This work quantifies the relative error that results from assuming laminar conduit flow for the interpretation of a synthetic large-scale pumping test in karst.

  9. Numerical Simulations of Plasma Based Flow Control Applications

    NASA Technical Reports Server (NTRS)

    Suzen, Y. B.; Huang, P. G.; Jacob, J. D.; Ashpis, D. E.

    2005-01-01

    A mathematical model was developed to simulate flow control applications using plasma actuators. The effects of the plasma actuators on the external flow are incorporated into Navier Stokes computations as a body force vector. In order to compute this body force vector, the model solves two additional equations: one for the electric field due to the applied AC voltage at the electrodes and the other for the charge density representing the ionized air. The model is calibrated against an experiment having plasma-driven flow in a quiescent environment and is then applied to simulate a low pressure turbine flow with large flow separation. The effects of the plasma actuator on control of flow separation are demonstrated numerically.

  10. Evaluation of cloud detection instruments and performance of laminar-flow leading-edge test articles during NASA Leading-Edge Flight-Test Program

    NASA Technical Reports Server (NTRS)

    Davis, Richard E.; Maddalon, Dal V.; Wagner, Richard D.; Fisher, David F.; Young, Ronald

    1989-01-01

    Summary evaluations of the performance of laminar-flow control (LFC) leading edge test articles on a NASA JetStar aircraft are presented. Statistics, presented for the test articles' performance in haze and cloud situations, as well as in clear air, show a significant effect of cloud particle concentrations on the extent of laminar flow. The cloud particle environment was monitored by two instruments, a cloud particle spectrometer (Knollenberg probe) and a charging patch. Both instruments are evaluated as diagnostic aids for avoiding laminar-flow detrimental particle concentrations in future LFC aircraft operations. The data base covers 19 flights in the simulated airline service phase of the NASA Leading-Edge Flight-Test (LEFT) Program.

  11. Needle-array to Plate DBD Plasma Using Sine AC and Nanosecond Pulse Excitations for Purpose of Improving Indoor Air Quality

    PubMed Central

    Zhang, Li; Yang, Dezheng; Wang, Wenchun; Wang, Sen; Yuan, Hao; Zhao, Zilu; Sang, Chaofeng; Jia, Li

    2016-01-01

    In this study, needle-array to plate electrode configuration was employed to generate an atmospheric air diffuse discharge using both nanosecond pulse and sine AC voltage as excitation voltage for the purpose of improving indoor air quality. Different types of voltage sources and electrode configurations are employed to optimize electrical field distribution and improve discharge stability. Discharge images, electrical characteristics, optical emission spectra, and plasma gas temperatures in both sine AC discharge and nanosecond pulse discharge were compared and the discharge stability during long operating time were discussed. Compared with the discharge excited by sine AC voltage, the nanosecond pulsed discharge is more homogenous and stable, besides, the plasma gas temperature of nanosecond pulse discharge is much lower. Using packed-bed structure, where γ- Al2O3 pellets are filled in the electrode gap, has obvious efficacy in the production of homogenous discharge. Furthermore, both sine AC discharge and nanosecond pulse discharge were used for removing formaldehyde from flowing air. It shows that nanosecond pulse discharge has a significant advantage in energy cost. And the main physiochemical processes for the generation of active species and the degradation of formaldehyde were discussed. PMID:27125663

  12. Successful enrichment of the ubiquitous freshwater acI Actinobacteria.

    PubMed

    Garcia, Sarahi L; McMahon, Katherine D; Grossart, Hans-Peter; Warnecke, Falk

    2014-02-01

    Actinobacteria of the acI lineage are often the numerically dominant bacterial phylum in surface freshwaters, where they can account for > 50% of total bacteria. Despite their abundance, there are no described isolates. In an effort to obtain enrichment of these ubiquitous freshwater Actinobacteria, diluted freshwater samples from Lake Grosse Fuchskuhle, Germany, were incubated in 96-well culture plates. With this method, a successful enrichment containing high abundances of a member of the lineage acI was established. Phylogenetic classification showed that the acI Actinobacteria of the enrichment belonged to the acI-B2 tribe, which seems to prefer acidic lakes. This enrichment grows to low cell densities and thus the oligotrophic nature of acI-B2 was confirmed. © 2013 Society for Applied Microbiology and John Wiley & Sons Ltd.

  13. Optimal Power Flow in Multiphase Radial Networks with Delta Connections: Preprint

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

    Zhao, Changhong; Dall-Anese, Emiliano; Low, Steven H.

    This paper focuses on multiphase radial distribution networks with mixed wye and delta connections, and proposes a semidefinite relaxation of the AC optimal power flow (OPF) problem. Two multiphase power-flow models are developed to facilitate the integration of delta-connected generation units/loads in the OPF problem. The first model extends traditional branch flow models - and it is referred to as extended branch flow model (EBFM). The second model leverages a linear relationship between per-phase power injections and delta connections, which holds under a balanced voltage approximation (BVA). Based on these models, pertinent OPF problems are formulated and relaxed to semidefinitemore » programs (SDPs). Numerical studies on IEEE test feeders show that SDP relaxations can be solved efficiently by a generic optimization solver. Numerical evidences indicate that solving the resultant SDP under BVA is faster than under EBFM. Moreover, both SDP solutions are numerically exact with respect to voltages and branch flows. It is also shown that the SDP solution under BVA has a small optimality gap, while the BVA model is accurate in the sense that it reflects actual system voltages.« less

  14. Calibration of the Flow in the Test Section of the Research Wind Tunnel at DST Group

    DTIC Science & Technology

    2015-10-01

    calibration of the flow in the test section of the Research Wind Tunnel at DST Group. The calibration was performed to establish the flow quality and to...of the Flow in the Test Section of the Research Wind Tunnel at DST Group Executive Summary The Defence Science and Technology Group (DST

  15. Flight Tests of a Supersonic Natural Laminar Flow Airfoil

    NASA Technical Reports Server (NTRS)

    Frederick, Mike; Banks, Dan; Garzon, Andres; Matisheck, Jason

    2014-01-01

    IR thermography was used to characterize the transition front on a S-NLF test article at chord Reynolds numbers in excess of 30 million Changes in transition due to Mach number, Reynolds number, and surface roughness were investigated - Regions of laminar flow in excess of 80% chord at chord Reynolds numbers greater than 14 million IR thermography clearly showed the transition front and other flow features such as shock waves impinging upon the surface A series of parallel oblique shocks, of yet unknown origin, were found to cause premature transition at higher Reynolds numbers. NASA has a current goal to eliminate barriers to the development of practical supersonic transport aircraft Drag reduction through the use of supersonic natural laminar flow (S-NLF) is currently being explored as a means of increasing aerodynamic efficiency - Tradeoffs work best for business jet class at M<2 Conventional high-speed designs minimize inviscid drag at the expense of viscous drag - Existence of strong spanwise pressure gradient leads to crossflow (CF) while adverse chordwise pressure gradients amplifies and Tollmien-Schlichting (TS) instabilities Aerion Corporation has patented a S-NLF wing design (US Patent No. 5322242) - Low sweep to control CF - dp/dx < 0 on both wing surfaces to stabilize TS - Thin wing with sharp leading edge to minimize wave drag increase due to reduction in sweep NASA and Aerion have partnered to study S-NLF since 1999 Series of S-NLF experiments flown on the NASA F-15B research test bed airplane Infrared (IR) thermography used to characterize transition - Non-intrusive, global, good spatial resolution - Captures significant flow features well

  16. Design of Distributed Controllers Seeking Optimal Power Flow Solutions Under Communication Constraints

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

    Dall'Anese, Emiliano; Simonetto, Andrea; Dhople, Sairaj

    This paper focuses on power distribution networks featuring inverter-interfaced distributed energy resources (DERs), and develops feedback controllers that drive the DER output powers to solutions of time-varying AC optimal power flow (OPF) problems. Control synthesis is grounded on primal-dual-type methods for regularized Lagrangian functions, as well as linear approximations of the AC power-flow equations. Convergence and OPF-solution-tracking capabilities are established while acknowledging: i) communication-packet losses, and ii) partial updates of control signals. The latter case is particularly relevant since it enables asynchronous operation of the controllers where DER setpoints are updated at a fast time scale based on local voltagemore » measurements, and information on the network state is utilized if and when available, based on communication constraints. As an application, the paper considers distribution systems with high photovoltaic integration, and demonstrates that the proposed framework provides fast voltage-regulation capabilities, while enabling the near real-time pursuit of solutions of AC OPF problems.« less

  17. 40 CFR 53.53 - Test for flow rate accuracy, regulation, measurement accuracy, and cut-off.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... pressures and temperatures used in the tests and shall be checked at zero and at least one flow rate within...: Equation 5 ER18jy97.067 (ii) To successfully pass the flow rate CV measurement accuracy test, the absolute...

  18. 40 CFR 53.53 - Test for flow rate accuracy, regulation, measurement accuracy, and cut-off.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... pressures and temperatures used in the tests and shall be checked at zero and at least one flow rate within...: Equation 5 ER18jy97.067 (ii) To successfully pass the flow rate CV measurement accuracy test, the absolute...

  19. 40 CFR 53.53 - Test for flow rate accuracy, regulation, measurement accuracy, and cut-off.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... pressures and temperatures used in the tests and shall be checked at zero and at least one flow rate within...: Equation 5 ER18jy97.067 (ii) To successfully pass the flow rate CV measurement accuracy test, the absolute...

  20. 40 CFR 53.53 - Test for flow rate accuracy, regulation, measurement accuracy, and cut-off.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... pressures and temperatures used in the tests and shall be checked at zero and at least one flow rate within...: Equation 5 ER18jy97.067 (ii) To successfully pass the flow rate CV measurement accuracy test, the absolute...

  1. Optimal In-Hospital and Discharge Medical Therapy in Acute Coronary Syndromes in Kerala: Results from the Kerala ACS Registry

    PubMed Central

    Huffman, Mark D; Prabhakaran, Dorairaj; Abraham, AK; Krishnan, Mangalath Narayanan; Nambiar, C. Asokan; Mohanan, Padinhare Purayil

    2013-01-01

    Background In-hospital and post-discharge treatment rates for acute coronary syndrome (ACS) remain low in India. However, little is known about the prevalence and predictors of the package of optimal ACS medical care in India. Our objective was to define the prevalence, predictors, and impact of optimal in-hospital and discharge medical therapy in the Kerala ACS Registry of 25,718 admissions. Methods and Results We defined optimal in-hospital ACS medical therapy as receiving the following five medications: aspirin, clopidogrel, heparin, beta-blocker, and statin. We defined optimal discharge ACS medical therapy as receiving all of the above therapies except heparin. Comparisons by optimal vs. non-optimal ACS care were made via Student’s t test for continuous variables and chi-square test for categorical variables. We created random effects logistic regression models to evaluate the association between GRACE risk score variables and optimal in-hospital or discharge medical therapy. Optimal in-hospital and discharge medical care was delivered in 40% and 46% of admissions, respectively. Wide variability in both in-hospital and discharge medical care was present with few hospitals reaching consistently high (>90%) levels. Patients receiving optimal in-hospital medical therapy had an adjusted OR (95%CI)=0.93 (0.71, 1.22) for in-hospital death and an adjusted OR (95%CI)=0.79 (0.63, 0.99) for MACE. Patients who received optimal in-hospital medical care were far more likely to receive optimal discharge care (adjusted OR [95%CI]=10.48 [9.37, 11.72]). Conclusions Strategies to improve in-hospital and discharge medical therapy are needed to improve local process-of-care measures and improve ACS outcomes in Kerala. PMID:23800985

  2. Role of HSF1-upregulated AC6 in ameliorating heart failure in mice.

    PubMed

    The, Erlinda; Du, Peizhao; Chang, Yaowei; Dai, Fangjie; Wei, Chunyan; Li, Jiming

    2016-10-01

    Our previous studies discovered that Heat shock factor 1(HSF1) can alleviate pressure overload induced heart failure in mice. However, its molecular mechanisms are yet to be further explained. Many studies have already verified that Adenylyl Cyclase 6 (AC6) can ameliorate heart failure, but it is still unknown whether or not the pathway HSF1 is involved in the process. Our preliminary experiment showed that the expression level of AC6 is positively associated with HSF1. Therefore, in the present study, we aimed to explore whether HSF1 can play its role in ameliorating heart failure by regulating AC6, and how the potential internal mechanisms work. We applied the Transverse Aortic Constriction (TAC) for 4 weeks to develop the C57BL/6 mice pressure overload induced heart failure model. First, the mice were divided into TAC group and SHAM group. Changes in the cardiac function and morphology of the mice were observed by an ultrasonic device and Masson staining slices, expressions of AC6 mRNA were observed by RT-QPCR, expressions of HSF1 and proteinkinase A (PKA) were examined by Western Blotting, and the levels of cyclic adenosine monophosphate (cAMP) from aortic blood were measured by ELISA. Second, the TAC group were further divided into subgroups of HSF1 transgene mice, HSF1 knockout mice and wild type mice, followed by the aforesaid observations. In the SHAM group, no obvious variations of cardiac function, AC6 mRNAHSF1, PKA, cAMP and other test results were found among each of the subgroups. Compared to the SHAM group, the TAC group presented clearly weakened heart functions, while, expressions of AC6 mRNA, HSF1, PKA and cAMP all recorded obvious increases. In the TAC group, compared to the WT subgroup, the HSF1 KO subgroup presented decreases in expressions of AC6 mRNA, HSF1, PKA and cAMP, and at the same time, the heart functions were weaker, while, the HSF1 TG subgroup recorded the contrary results. In the pressure overload heart failure model, HSF1 can

  3. Acoustic tests of a 15.2 centimeter-diameter potential flow convergent nozzle

    NASA Technical Reports Server (NTRS)

    Karchmer, A. M.; Dorsch, R. G.; Friedman, R.

    1974-01-01

    An experimental investigation of the jet noise radiated to the far field from a 15.2-cm-diam potential flow convergent nozzle has been conducted. Tests were made with unheated airflow over a range of subsonic nozzle exhaust velocities from 62 to 310m/sec. Mean and turbulent velocity measurements in the flow field of the nozzle exhaust indicated no apparent flow anomalies. Acoustic measurements yielded data uncontaminated by internal and/or background noise to velocities as low as 152m/sec. Finally, no significantly different acoustic characteristics between the potential flow nozzle and simple convergent nozzles were found.

  4. Development of a Streamlined Work Flow for Handling Patients' Genetic Testing Insurance Authorizations.

    PubMed

    Uhlmann, Wendy R; Schwalm, Katie; Raymond, Victoria M

    2017-08-01

    Obtaining genetic testing insurance authorizations for patients is a complex, time-involved process often requiring genetic counselor (GC) and physician involvement. In an effort to mitigate this complexity and meet the increasing number of genetic testing insurance authorization requests, GCs formed a novel partnership with an industrial engineer (IE) and a patient services associate (PSA) to develop a streamlined work flow. Eight genetics clinics and five specialty clinics at the University of Michigan were surveyed to obtain benchmarking data. Tasks needed for genetic testing insurance authorization were outlined and time-saving work flow changes were introduced including 1) creation of an Excel password-protected shared database between GCs and PSAs, used for initiating insurance authorization requests, tracking and follow-up 2) instituting the PSAs sending GCs a pre-clinic email noting each patients' genetic testing insurance coverage 3) inclusion of test medical necessity documentation in the clinic visit summary note instead of writing a separate insurance letter and 4) PSAs development of a manual with insurance providers and genetic testing laboratories information. These work flow changes made it more efficient to request and track genetic testing insurance authorizations for patients, enhanced GCs and PSAs communication, and reduced tasks done by clinicians.

  5. Characterization and snubbing of a bidirectional MCT in a resonant ac link converter

    NASA Technical Reports Server (NTRS)

    Lee, Tony; Elbuluk, Malik E.; Zinger, Donald S.

    1993-01-01

    The MOS-Controlled Thyristor (MCT) is emerging as a powerful switch that combines the better characteristics of existing power devices. A study of switching stresses on an MCT switch under zero voltage resonant switching is presented. The MCT is used as a bidirectional switch in an ac/ac pulse density modulated inverter for induction motor drive. Current and voltage spikes are observed and analyzed with variations in the timing of the switching. Different snubber circuit configurations are under investigation to minimize the effect of these transients. The results will be extended to study and test the MCT switching in a medium power (5 hp) induction motor drive.

  6. 21 CFR 880.5510 - Non-AC-powered patient lift.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Non-AC-powered patient lift. 880.5510 Section 880... Devices § 880.5510 Non-AC-powered patient lift. (a) Identification. A non-AC-powered patient lift is a hydraulic, battery, or mechanically powered device, either fixed or mobile, used to lift and transport a...

  7. 21 CFR 880.5510 - Non-AC-powered patient lift.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Non-AC-powered patient lift. 880.5510 Section 880... Devices § 880.5510 Non-AC-powered patient lift. (a) Identification. A non-AC-powered patient lift is a hydraulic, battery, or mechanically powered device, either fixed or mobile, used to lift and transport a...

  8. Nuclear structure of 231Ac

    NASA Astrophysics Data System (ADS)

    Boutami, R.; Borge, M. J. G.; Mach, H.; Kurcewicz, W.; Fraile, L. M.; Gulda, K.; Aas, A. J.; García-Raffi, L. M.; Løvhøiden, G.; Martínez, T.; Rubio, B.; Taín, J. L.; Tengblad, O.

    2008-10-01

    The low-energy structure of 231Ac has been investigated by means of γ ray spectroscopy following the β decay of 231Ra. Multipolarities of 28 transitions have been established by measuring conversion electrons with a MINI-ORANGE electron spectrometer. The decay scheme of 231Ra → 231Ac has been constructed for the first time. The Advanced Time Delayed βγγ(t) method has been used to measure the half-lives of five levels. The moderately fast B(E1) transition rates derived suggest that the octupole effects, albeit weak, are still present in this exotic nucleus.

  9. Autographa californica multiple nucleopolyhedrovirus ac53 plays a role in nucleocapsid assembly

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

    Liu Chao; Li Zhaofei; Wu Wenbi

    2008-12-05

    Autographa californica multiple nucleopolyhedrovirus (AcMNPV) orf53 (ac53) is a highly conserved gene existing in all sequenced Lepidoptera and Hymenoptera baculoviruses, but its function remains unknown. To investigate its role in the baculovirus life cycle, an ac53 deletion virus (vAc{sup ac53KO-PH-GFP}) was generated through homologous recombination in Escherichia coli. Fluorescence and light microscopy and titration analysis revealed that vAc{sup ac53KO-PH-GFP} could not produce infectious budded virus in infected Sf9 cells. Real-time PCR demonstrated that the ac53 deletion did not affect the levels of viral DNA replication. Electron microscopy showed that many lucent tubular shells devoid of the nucleoprotein core are presentmore » in the virogenic stroma and ring zone, indicating that the ac53 knockout affected nucleocapsid assembly. With a recombinant virus expressing an Ac53-GFP fusion protein, we observed that Ac53 was distributed within the cytoplasm and nucleus at 24 h post-infection, but afterwards accumulated predominantly near the nucleus-cytoplasm boundary. These data demonstrate that ac53 is involved in nucleocapsid assembly and is an essential gene for virus production.« less

  10. The NASA Juncture Flow Experiment: Goals, Progress, and Preliminary Testing (Invited)

    NASA Technical Reports Server (NTRS)

    Rumsey, Christopher L.; Neuhart, Danny H.; Kegerise, Michael A.

    2016-01-01

    NASA has been working toward designing and conducting a juncture flow experiment on a wing-body aircraft configuration. The experiment is planned to provide validation-quality data for CFD that focuses on the onset and progression of a separation bubble near the wing-body juncture trailing edge region. This paper describes the goals and purpose of the experiment. Although currently considered unreliable, preliminary CFD analyses of several different configurations are shown. These configurations have been subsequently tested in a series of "risk-reduction" wind tunnel tests, in order to help down-select to a final configuration that will attain the desired flow behavior. The risk-reduction testing at the higher Reynolds number has not yet been completed (at the time of this writing), but some results from one of the low-Reynolds-number experiments are shown.

  11. Wind Tunnel Test of a Risk-Reduction Wing/Fuselage Model to Examine Juncture-Flow Phenomena

    NASA Technical Reports Server (NTRS)

    Kegerise, Michael A.; Neuhart, Dan H.

    2016-01-01

    A wing/fuselage wind-tunnel model was tested in the Langley 14- by 22-foot Subsonic Wind Tunnel in preparation for a highly-instrumented Juncture Flow Experiment to be conducted in the same facility. This test, which was sponsored by the NASA Transformational Tool and Technologies Project, is part of a comprehensive set of experimental and computational research activities to develop revolutionary, physics-based aeronautics analysis and design capability. The objectives of this particular test were to examine the surface and off-body flow on a generic wing/body combination to: 1) choose a final wing for a future, highly instrumented model, 2) use the results to facilitate unsteady pressure sensor placement on the model, 3) determine the area to be surveyed with an embedded laser-doppler velocimetry (LDV) system, 4) investigate the primary juncture corner- flow separation region using particle image velocimetry (PIV) to see if the particle seeding is adequately entrained and to examine the structure in the separated region, and 5) to determine the similarity of observed flow features with those predicted by computational fluid dynamics (CFD). This report documents the results of the above experiment that specifically address the first three goals. Multiple wing configurations were tested at a chord Reynolds number of 2.4 million. Flow patterns on the surface of the wings and in the region of the wing/fuselage juncture were examined using oil- flow visualization and infrared thermography. A limited number of unsteady pressure sensors on the fuselage around the wing leading and trailing edges were used to identify any dynamic effects of the horseshoe vortex on the flow field. The area of separated flow in the wing/fuselage juncture near the wing trailing edge was observed for all wing configurations at various angles of attack. All of the test objectives were met. The staff of the 14- by 22-foot Subsonic Wind Tunnel provided outstanding support and delivered

  12. (NTF) National Transonic Facility Test 213-SFW Flow Control II,

    NASA Image and Video Library

    2012-11-19

    (NTF) National Transonic Facility Test 213-SFW Flow Control II, Fast-MAC Model: The fundamental Aerodynamics Subsonic Transonic-Modular Active Control (Fast-MAC) Model was tested for the 2nd time in the NTF. The objectives were to document the effects of Reynolds numbers on circulation control aerodynamics and to develop and open data set for CFD code validation. Image taken in building 1236, National Transonic Facility

  13. Non-compliance with ACS-COT recommended criteria for full trauma team activation is associated with undertriage deaths.

    PubMed

    Tignanelli, Christopher J; Vander Kolk, Wayne E; Mikhail, Judy N; Delano, Matthew J; Hemmila, Mark R

    2017-11-21

    The appropriate triage of acutely injured patients within a trauma system is associated with improved rates of mortality and optimal resource utilization. The American College of Surgeons Committee on Trauma (ACS-COT) put forward six minimum criteria (ACS-6) for full trauma team activation (TTA). We hypothesized that ACS-COT verified trauma center compliance with these criteria is associated with low under-triage rates and improved overall mortality. Data from a state-wide collaborative quality initiative was utilized. We used data collected from 2014 through 2016 at 29 ACS verified level 1 and 2 trauma centers. Inclusion criteria were: adult patients (≥16 years) and ISS ≥5. Quantitative data existed to analyze four of the ACS-6 criteria (ED SBP≤90 mmHg, respiratory compromise/intubation, central GSW, and GCS<9). Patients were considered to be under-triaged if they had major trauma (ISS>15) and did not receive a full TTA. 51,792 patients were included in the study. Compliance with ACS-6 minimum criteria for full TTA varied from 51% to 82%. Presence of any ACS-6 criteria was associated with a high intervention rate and significant risk of mortality (OR 16.7, 95% CI 15.2-18.3, p<0.001). Of the 1004 deaths that were not a full activation, 433 (43%) were classified as under-triaged, and 301 (30%) had at least one ACS-6 criteria present. Under-triaged patients with any ACS-6 criteria were more likely to die than those who were not under-triaged (30% vs 21%, p=0.001). GCS<9 and need for emergent intubation were the ACS-6 criteria most frequently associated with under-triage mortality. Compliance with ACS-COT minimum criteria for full TTA remains sub-optimal and undertriage is associated with increased mortality. This data suggests that the most efficient quality improvement measure around triage should be ensuring compliance with the ACS-6 criteria. This study suggests that practice pattern modification to more strictly adhere to the minimum ACS-COT criteria for

  14. Aligning fast alternating current electroosmotic flow fields and characteristic frequencies with dielectrophoretic traps to achieve rapid bacteria detection.

    PubMed

    Gagnon, Zachary; Chang, Hsueh-Chia

    2005-10-01

    Tailor-designed alternating current electroosmotic (AC-EO) stagnation flows are used to convect bioparticles globally from a bulk solution to localized dielectrophoretic (DEP) traps that are aligned at the flow stagnation points. The multiscale trap, with a typical trapping time of seconds for a dilute 70 microL volume of 10(3) particles per cc sample, is several orders of magnitude faster than conventional DEP traps and earlier AC-EO traps with parallel, castellated, or finger electrodes. A novel serpentine wire capable of sustaining a high voltage, up to 2500 V(RMS), without causing excessive heat dissipation or Faradaic reaction in strong electrolytes is fabricated to produce the strong AC-EO flow with two separated stagnation lines, one aligned with the field minimum and one with the field maximum. The continuous wire design allows a large applied voltage without inducing Faradaic electrode reactions. Particles are trapped within seconds at one of the traps depending on whether they suffer negative or positive DEP. The particles can also be rapidly released from their respective traps by varying the frequency of the applied AC field below particle-distinct cross-over frequencies. Zwitterion addition to the buffer allows further geometric and frequency alignments of the AC-EO and DEP motions. The same device hence allows fast trapping, detection, sorting, and characterization on a sample with realistic conductivity, volume, and bacteria count.

  15. Numerical simulation of failure behavior of granular debris flows based on flume model tests.

    PubMed

    Zhou, Jian; Li, Ye-xun; Jia, Min-cai; Li, Cui-na

    2013-01-01

    In this study, the failure behaviors of debris flows were studied by flume model tests with artificial rainfall and numerical simulations (PFC(3D)). Model tests revealed that grain sizes distribution had profound effects on failure mode, and the failure in slope of medium sand started with cracks at crest and took the form of retrogressive toe sliding failure. With the increase of fine particles in soil, the failure mode of the slopes changed to fluidized flow. The discrete element method PFC(3D) can overcome the hypothesis of the traditional continuous medium mechanic and consider the simple characteristics of particle. Thus, a numerical simulations model considering liquid-solid coupled method has been developed to simulate the debris flow. Comparing the experimental results, the numerical simulation result indicated that the failure mode of the failure of medium sand slope was retrogressive toe sliding, and the failure of fine sand slope was fluidized sliding. The simulation result is consistent with the model test and theoretical analysis, and grain sizes distribution caused different failure behavior of granular debris flows. This research should be a guide to explore the theory of debris flow and to improve the prevention and reduction of debris flow.

  16. Cold Flow Testing for Liquid Propellant Rocket Injector Scaling and Throttling

    NASA Technical Reports Server (NTRS)

    Kenny, Jeremy R.; Moser, Marlow D.; Hulka, James; Jones, Gregg

    2006-01-01

    Scaling and throttling of combustion devices are important capabilities to demonstrate in development of liquid rocket engines for NASA's Space Exploration Mission. Scaling provides the ability to design new injectors and injection elements with predictable performance on the basis of test experience with existing injectors and elements, and could be a key aspect of future development programs. Throttling is the reduction of thrust with fixed designs and is a critical requirement in lunar and other planetary landing missions. A task in the Constellation University Institutes Program (CUIP) has been designed to evaluate spray characteristics when liquid propellant rocket engine injectors are scaled and throttled. The specific objectives of the present study are to characterize injection and primary atomization using cold flow simulations of the reacting sprays. These simulations can provide relevant information because the injection and primary atomization are believed to be the spray processes least affected by the propellant reaction. Cold flow studies also provide acceptable test conditions for a university environment. Three geometric scales - 1/4- scale, 1/2-scale, and full-scale - of two different injector element types - swirl coaxial and shear coaxial - will be designed, fabricated, and tested. A literature review is currently being conducted to revisit and compile the previous scaling documentation. Because it is simple to perform, throttling will also be examined in the present work by measuring primary atomization characteristics as the mass flow rate and pressure drop of the six injector element concepts are reduced, with corresponding changes in chamber backpressure. Simulants will include water and gaseous nitrogen, and an optically accessible chamber will be used for visual and laser-based diagnostics. The chamber will include curtain flow capability to repress recirculation, and additional gas injection to provide independent control of the

  17. Mechanical Design of a Performance Test Rig for the Turbine Air-Flow Task (TAFT)

    NASA Technical Reports Server (NTRS)

    Forbes, John C.; Xenofos, George D.; Farrow, John L.; Tyler, Tom; Williams, Robert; Sargent, Scott; Moharos, Jozsef

    2004-01-01

    To support development of the Boeing-Rocketdyne RS84 rocket engine, a full-flow, reaction turbine geometry was integrated into the NASA-MSFC turbine air-flow test facility. A mechanical design was generated which minimized the amount of new hardware while incorporating all test and instrumentation requirements. This paper provides details of the mechanical design for this Turbine Air-Flow Task (TAFT) test rig. The mechanical design process utilized for this task included the following basic stages: Conceptual Design. Preliminary Design. Detailed Design. Baseline of Design (including Configuration Control and Drawing Revision). Fabrication. Assembly. During the design process, many lessons were learned that should benefit future test rig design projects. Of primary importance are well-defined requirements early in the design process, a thorough detailed design package, and effective communication with both the customer and the fabrication contractors.

  18. Optimization of spin-torque switching using AC and DC pulses

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

    Dunn, Tom; Kamenev, Alex; Fine Theoretical Physics Institute, University of Minnesota, Minneapolis, Minnesota 55455

    2014-06-21

    We explore spin-torque induced magnetic reversal in magnetic tunnel junctions using combined AC and DC spin-current pulses. We calculate the optimal pulse times and current strengths for both AC and DC pulses as well as the optimal AC signal frequency, needed to minimize the Joule heat lost during the switching process. The results of this optimization are compared against numeric simulations. Finally, we show how this optimization leads to different dynamic regimes, where switching is optimized by either a purely AC or DC spin-current, or a combination AC/DC spin-current, depending on the anisotropy energies and the spin-current polarization.

  19. Operational evaluation of a proppeller test stand in the quiet flow facility at Langley Research Center

    NASA Technical Reports Server (NTRS)

    Block, P. J. W.

    1982-01-01

    Operational proof tests of a propeller test stand (PTS) in a quiet flow facility (QFF) are presented. The PTS is an experimental test bed for acoustic propeller research in the quiet flow environment of the QFF. These proof tests validate thrust and torque predictions, examine the repeatability of measurements on the PTS, and determine the effect of applying artificial roughness to the propeller blades. Since a thrusting propeller causes an open jet to contract, the potential flow core was surveyed to examine the magnitude of the contraction. These measurements are compared with predicted values. The predictions are used to determine operational limitations for testing a given propeller design in the QFF.

  20. Alpha Power Increase After Transcranial Alternating Current Stimulation at Alpha Frequency (α-tACS) Reflects Plastic Changes Rather Than Entrainment

    PubMed Central

    Vossen, Alexandra; Gross, Joachim; Thut, Gregor

    2015-01-01

    Background Periodic stimulation of occipital areas using transcranial alternating current stimulation (tACS) at alpha (α) frequency (8–12 Hz) enhances electroencephalographic (EEG) α-oscillation long after tACS-offset. Two mechanisms have been suggested to underlie these changes in oscillatory EEG activity: tACS-induced entrainment of brain oscillations and/or tACS-induced changes in oscillatory circuits by spike-timing dependent plasticity. Objective We tested to what extent plasticity can account for tACS-aftereffects when controlling for entrainment “echoes.” To this end, we used a novel, intermittent tACS protocol and investigated the strength of the aftereffect as a function of phase continuity between successive tACS episodes, as well as the match between stimulation frequency and endogenous α-frequency. Methods 12 healthy participants were stimulated at around individual α-frequency for 11–15 min in four sessions using intermittent tACS or sham. Successive tACS events were either phase-continuous or phase-discontinuous, and either 3 or 8 s long. EEG α-phase and power changes were compared after and between episodes of α-tACS across conditions and against sham. Results α-aftereffects were successfully replicated after intermittent stimulation using 8-s but not 3-s trains. These aftereffects did not reveal any of the characteristics of entrainment echoes in that they were independent of tACS phase-continuity and showed neither prolonged phase alignment nor frequency synchronization to the exact stimulation frequency. Conclusion Our results indicate that plasticity mechanisms are sufficient to explain α-aftereffects in response to α-tACS, and inform models of tACS-induced plasticity in oscillatory circuits. Modifying brain oscillations with tACS holds promise for clinical applications in disorders involving abnormal neural synchrony. PMID:25648377

  1. Alpha Power Increase After Transcranial Alternating Current Stimulation at Alpha Frequency (α-tACS) Reflects Plastic Changes Rather Than Entrainment.

    PubMed

    Vossen, Alexandra; Gross, Joachim; Thut, Gregor

    2015-01-01

    Periodic stimulation of occipital areas using transcranial alternating current stimulation (tACS) at alpha (α) frequency (8-12 Hz) enhances electroencephalographic (EEG) α-oscillation long after tACS-offset. Two mechanisms have been suggested to underlie these changes in oscillatory EEG activity: tACS-induced entrainment of brain oscillations and/or tACS-induced changes in oscillatory circuits by spike-timing dependent plasticity. We tested to what extent plasticity can account for tACS-aftereffects when controlling for entrainment "echoes." To this end, we used a novel, intermittent tACS protocol and investigated the strength of the aftereffect as a function of phase continuity between successive tACS episodes, as well as the match between stimulation frequency and endogenous α-frequency. 12 healthy participants were stimulated at around individual α-frequency for 11-15 min in four sessions using intermittent tACS or sham. Successive tACS events were either phase-continuous or phase-discontinuous, and either 3 or 8 s long. EEG α-phase and power changes were compared after and between episodes of α-tACS across conditions and against sham. α-aftereffects were successfully replicated after intermittent stimulation using 8-s but not 3-s trains. These aftereffects did not reveal any of the characteristics of entrainment echoes in that they were independent of tACS phase-continuity and showed neither prolonged phase alignment nor frequency synchronization to the exact stimulation frequency. Our results indicate that plasticity mechanisms are sufficient to explain α-aftereffects in response to α-tACS, and inform models of tACS-induced plasticity in oscillatory circuits. Modifying brain oscillations with tACS holds promise for clinical applications in disorders involving abnormal neural synchrony. Copyright © 2015 The Authors. Published by Elsevier Inc. All rights reserved.

  2. Influence of movable test section elements configuration on its drag and flow field uniformity at transonic speeds

    NASA Astrophysics Data System (ADS)

    Glazkov, S. A.; Gorbushin, A. R.; Osipova, S. L.; Semenov, A. V.

    2016-10-01

    The report describes the results of flow field experimental research in TsAGI T-128 transonic wind tunnel. During the tests Mach number, stagnation pressure, test section wall perforation ratio, angles between the test section panels and mixing chamber flaps varied. Based on the test results one determined corrections to the free-stream Mach number related to the flow speed difference in the model location and in the zone of static pressure measurement on the test section walls, nonuniformity of the longitudinal velocity component in the model location, optimal position of the movable test section elements to provide flow field uniformity in the test section and minimize the test leg drag.

  3. Application for Single Price Auction Model (SPA) in AC Network

    NASA Astrophysics Data System (ADS)

    Wachi, Tsunehisa; Fukutome, Suguru; Chen, Luonan; Makino, Yoshinori; Koshimizu, Gentarou

    This paper aims to develop a single price auction model with AC transmission network, based on the principle of maximizing social surplus of electricity market. Specifically, we first formulate the auction market as a nonlinear optimization problem, which has almost the same form as the conventional optimal power flow problem, and then propose an algorithm to derive both market clearing price and trade volume of each player even for the case of market-splitting. As indicated in the paper, the proposed approach can be used not only for the price evaluation of auction or bidding market but also for analysis of bidding strategy, congestion effect and other constraints or factors. Several numerical examples are used to demonstrate effectiveness of our method.

  4. Mechanical Design of a Performance Test Rig for the Turbine Air-Flow Task (TAFT)

    NASA Technical Reports Server (NTRS)

    Xenofos, George; Forbes, John; Farrow, John; Williams, Robert; Tyler, Tom; Sargent, Scott; Moharos, Jozsef

    2003-01-01

    To support development of the Boeing-Rocketdyne RS84 rocket engine, a fill-flow, reaction turbine geometry was integrated into the NASA-MSFC turbine air-flow test facility. A mechanical design was generated which minimized the amount of new hardware while incorporating all test and instrUmentation requirements. This paper provides details of the mechanical design for this Turbine Air-Flow Task (TAFT) test rig. The mechanical design process utilized for this task included the following basic stages: Conceptual Design. Preliminary Design. Detailed Design. Baseline of Design (including Configuration Control and Drawing Revision). Fabrication. Assembly. During the design process, many lessons were learned that should benefit future test rig design projects. Of primary importance are well-defined requirements early in the design process, a thorough detailed design package, and effective communication with both the customer and the fabrication contractors. The test rig provided steady and unsteady pressure data necessary to validate the computational fluid dynamics (CFD) code. The rig also helped characterize the turbine blade loading conditions. Test and CFD analysis results are to be presented in another JANNAF paper.

  5. A Single-Phase Embedded Z-Source DC-AC Inverter

    PubMed Central

    Kim, Se-Jin; Lim, Young-Cheol

    2014-01-01

    In the conventional DC-AC inverter consisting of two DC-DC converters with unipolar output capacitors, the output capacitor voltages of the DC-DC converters must be higher than the DC input voltage. To overcome this weakness, this paper proposes a single-phase DC-AC inverter consisting of two embedded Z-source converters with bipolar output capacitors. The proposed inverter is composed of two embedded Z-source converters with a common DC source and output AC load. Though the output capacitor voltages of the converters are relatively low compared to those of a conventional inverter, an equivalent level of AC output voltages can be obtained. Moreover, by controlling the output capacitor voltages asymmetrically, the AC output voltage of the proposed inverter can be higher than the DC input voltage. To verify the validity of the proposed inverter, experiments were performed with a DC source voltage of 38 V. By controlling the output capacitor voltages of the converters symmetrically or asymmetrically, the proposed inverter can produce sinusoidal AC output voltages. The experiments show that efficiencies of up to 95% and 97% can be achieved with the proposed inverter using symmetric and asymmetric control, respectively. PMID:25133241

  6. A single-phase embedded Z-source DC-AC inverter.

    PubMed

    Kim, Se-Jin; Lim, Young-Cheol

    2014-01-01

    In the conventional DC-AC inverter consisting of two DC-DC converters with unipolar output capacitors, the output capacitor voltages of the DC-DC converters must be higher than the DC input voltage. To overcome this weakness, this paper proposes a single-phase DC-AC inverter consisting of two embedded Z-source converters with bipolar output capacitors. The proposed inverter is composed of two embedded Z-source converters with a common DC source and output AC load. Though the output capacitor voltages of the converters are relatively low compared to those of a conventional inverter, an equivalent level of AC output voltages can be obtained. Moreover, by controlling the output capacitor voltages asymmetrically, the AC output voltage of the proposed inverter can be higher than the DC input voltage. To verify the validity of the proposed inverter, experiments were performed with a DC source voltage of 38 V. By controlling the output capacitor voltages of the converters symmetrically or asymmetrically, the proposed inverter can produce sinusoidal AC output voltages. The experiments show that efficiencies of up to 95% and 97% can be achieved with the proposed inverter using symmetric and asymmetric control, respectively.

  7. An AC modulated near infrared gain calibration system for a “Violin-Mode” transimpedance amplifier, intended for advanced LIGO suspensions

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

    Lockerbie, N. A.; Tokmakov, K. V.

    The background to this work was a prototype shadow sensor, which was designed for retro-fitting to an advanced LIGO (Laser Interferometer Gravitational wave Observatory) test-mass/mirror suspension, in which a 40 kg test-mass/mirror is suspended by four approximately 600 mm long by 0.4 mm diameter fused-silica suspension fibres. The shadow sensor comprised a LED source of Near InfraRed (NIR) radiation, and a “tall-thin” rectangular silicon photodiode detector, which together were to bracket the fibre under test. The photodiode was positioned so as to be sensitive (primarily) to transverse “Violin-Mode” vibrations of such a fibre, via the oscillatory movement of the shadowmore » cast by the fibre, as this moved across the face of the detector. In this prototype shadow sensing system the photodiode was interfaced to a purpose-built transimpedance amplifier, this having both AC and DC outputs. A quasi-static calibration was made of the sensor’s DC responsivity, i.e., incremental rate of change of output voltage versus fibre position, by slowly scanning a fused-silica fibre sample transversely through the illuminating beam. The work reported here concerns the determination of the sensor’s more important AC (Violin-Mode) responsivity. Recognition of the correspondence between direct AC modulation of the source, and actual Violin-Mode signals, and of the transformative role of the AC/DC gain ratio for the amplifier, at any modulation frequency, f, resulted in the construction of the AC/DC calibration source described here. A method for determining in practice the transimpedance AC/DC gain ratio of the photodiode and amplifier, using this source, is illustrated by a specific numerical example, and the gain ratio for the prototype sensing system is reported over the frequency range 1 Hz–300 kHz. In fact, a maximum DC responsivity of 1.26 kV.m{sup −1} was measured using the prototype photodiode sensor and amplifier discussed here. Therefore, the measured

  8. Nano-iron Tracer Test for Characterizing Preferential Flow Path in Fractured Rock

    NASA Astrophysics Data System (ADS)

    Chia, Y.; Chuang, P. Y.

    2015-12-01

    Deterministic description of the discrete features interpreted from site characterization is desirable for developing a discrete fracture network conceptual model. It is often difficult, however, to delineate preferential flow path through a network of discrete fractures in the field. A preliminary cross-borehole nano-iron tracer test was conducted to characterize the preferential flow path in fractured shale bedrock at a hydrogeological research station. Prior to the test, heat-pulse flowmeter measurements were performed to detect permeable fracture zones at both the injection well and the observation well. While a few fracture zones are found permeable, most are not really permeable. Chemical reduction method was used to synthesize nano zero-valent iron particles with a diameter of 50~150 nm. The conductivity of nano-iron solution is about 3100 μs/cm. The recorded fluid conductivity shows the arrival of nano-iron solution in the observation well 11.5 minutes after it was released from the injection well. The magnetism of zero-valent iron enables it to be absorbed on magnet array designed to locate the depth of incoming tracer. We found nearly all of absorbed iron on the magnet array in the observation well were distributed near the most permeable fracture zone. The test results revealed a preferential flow path through a permeable fracture zone between the injection well and the observation well. The estimated hydraulic conductivity of the connected fracture is 2.2 × 10-3 m/s. This preliminary study indicated that nano-iron tracer test has the potential to characterize preferential flow path in fractured rock.

  9. Post-Flash Validation of the new ACS/WFC Subarrays

    NASA Astrophysics Data System (ADS)

    Bellini, A.; Grogin, N. A.; Lim, P. L.; Golimowski, D.

    2017-05-01

    We made use of the new ACS/WFC subarray images of CAL-14410, taken taken with a large range of flash exposure times (0.1-30 seconds), to probe the temporal stability of the reference flash file and to validate the current post-flash correction pipeline of CALACS and ACS DESTRIPE PLUS on the new subarray modes. No statistically-significant deviations are found between the new post-flashed subarray exposures and the flash reference file, indicating that the LED lamp used to post-flash ACS images has been stable over several years. The current calibration pipelines (both CALACS and ACS DESTRIPE PLUS can be successfully used with the new subarray modes.

  10. Water Flow Testing and Unsteady Pressure Analysis of a Two-Bladed Liquid Oxidizer Pump Inducer

    NASA Technical Reports Server (NTRS)

    Schwarz, Jordan B.; Mulder, Andrew; Zoladz, Thomas

    2011-01-01

    The unsteady fluid dynamic performance of a cavitating two-bladed oxidizer turbopump inducer was characterized through sub-scale water flow testing. While testing a novel inlet duct design that included a cavitation suppression groove, unusual high-frequency pressure oscillations were observed. With potential implications for inducer blade loads, these high-frequency components were analyzed extensively in order to understand their origins and impacts to blade loading. Water flow testing provides a technique to determine pump performance without the costs and hazards associated with handling cryogenic propellants. Water has a similar density and Reynolds number to liquid oxygen. In a 70%-scale water flow test, the inducer-only pump performance was evaluated. Over a range of flow rates, the pump inlet pressure was gradually reduced, causing the flow to cavitate near the pump inducer. A nominal, smooth inducer inlet was tested, followed by an inlet duct with a circumferential groove designed to suppress cavitation. A subsequent 52%-scale water flow test in another facility evaluated the combined inducer-impeller pump performance. With the nominal inlet design, the inducer showed traditional cavitation and surge characteristics. Significant bearing loads were created by large side loads on the inducer during synchronous cavitation. The grooved inlet successfully mitigated these loads by greatly reducing synchronous cavitation, however high-frequency pressure oscillations were observed over a range of frequencies. Analytical signal processing techniques showed these oscillations to be created by a rotating, multi-celled train of pressure pulses, and subsequent CFD analysis suggested that such pulses could be created by the interaction of rotating inducer blades with fluid trapped in a cavitation suppression groove. Despite their relatively low amplitude, these high-frequency pressure oscillations posed a design concern due to their sensitivity to flow conditions and

  11. A mercury flow meter for ion thruster testing. [response time, thermal sensitivity

    NASA Technical Reports Server (NTRS)

    Wilbur, P. J.

    1973-01-01

    The theory of operation of the thermal flow meter is presented, and a theoretical model is used to determine design parameters for a device capable of measuring mercury flows in the range of 0 to 5 gm/hr. Flow meter construction is described. Tests performed using a positive displacement mercury pump as well as those performed with the device in the feed line of an operating thruster are discussed. A flow meter response time of about a minute and a sensitivity of about 10 mv/gm/hr are demonstrated. Additional work to relieve a sensitivity of the device to variations in ambient temperature is indicated to improve its quantitative performance.

  12. Flexible, polymer gated, AC-driven organic electroluminescence devices

    NASA Astrophysics Data System (ADS)

    Xu, Junwei; Carroll, David L.

    2017-08-01

    Comparing rigid inorganic layer, polymeric semiconducting gate layer exhibits superior flexibility as well as efficient carrier manipulation in high frequency AC cycles. Mechanism of the carrier manipulation at the gate in forward and reversed bias of AC cycle is studied. The flexible PET-based AC-OEL device with poly[(9,9-bis(3'-((N,N-dimethyl)-Nethylammonium)- propyl)-2,7-fluorene)-alt-2,7-(9,9-dioctylfluorene)] (PFN-Br) gate shows a stable electroluminescent performance in frequency sweep with a color rendering index (CRI) over 81 at 2800K color temperature.

  13. Characterization Of Flow Stress Of Different AA6082 Alloys By Means Of Hot Torsion Test

    NASA Astrophysics Data System (ADS)

    Donati, Lorenzo; El Mehtedi, Mohamad

    2011-05-01

    FEM simulations are become the most powerful tools in order to optimize the different aspects of the extrusion process and an accurate flow stress definition of the alloy is a prerequisite for a reliable effectiveness of the simulation. In the paper the determination of flow stress by means of hot torsion test is initially presented and discussed: the several approximations that are usually introduced in flow stress computation are described and computed for an AA6082 alloy in order to evidence the final effect on curves shapes. The procedure for regressing the parameters of the sinhyperbolic flow stress definition is described in detailed and applied to the described results. Then four different alloys, extracted by different casting batches but all namely belonging to the 6082 class, were hot torsion tested in comparable levels of temperature and strain rate up to specimen failure. The results are analyzed and discussed in order to understand if a mean flow stress behavior can be identified for the whole material class at the different tested conditions or if specific testing conditions (chemical composition of the alloy, specimen shape, etc) influence the materials properties to a higher degree.

  14. Ultra high bypass Nacelle aerodynamics inlet flow-through high angle of attack distortion test

    NASA Technical Reports Server (NTRS)

    Larkin, Michael J.; Schweiger, Paul S.

    1992-01-01

    A flow-through inlet test program was conducted to evaluate inlet test methods and determine the impact of the fan on inlet separation when operating at large angles of attack. A total of 16 model configurations of approximately 1/6 scale were tested. A comparison of these flow-through results with powered data indicates the presence of the fan increased separation operation 3 degrees to 4 degrees over the flow through inlet. Rods and screens located at the fan face station, that redistribute the flow, achieved simulation of the powered-fan results for separation angle of attack. Concepts to reduce inlet distortion and increase angle of attack capability were also evaluated. Vortex generators located on the inlet surface increased inlet angle of attack capability up to 2 degrees and reduced inlet distortion in the separated region. Finally, a method of simulating the fan/inlet aerodynamic interaction using blockage sizing method has been defined. With this method, a static blockage device used with a flow-through model will approximate the same inlet onset of separation angle of attack and distortion pattern that would be obtained with an inlet model containing a powered fan.

  15. dc Arc Fault Effect on Hybrid ac/dc Microgrid

    NASA Astrophysics Data System (ADS)

    Fatima, Zahra

    The advent of distributed energy resources (DER) and reliability and stability problems of the conventional grid system has given rise to the wide spread deployment of microgrids. Microgrids provide many advantages by incorporating renewable energy sources and increasing the reliability of the grid by isolating from the main grid in case of an outage. AC microgrids have been installed all over the world, but dc microgrids have been gaining interest due to the advantages they provide over ac microgrids. However the entire power network backbone is still ac and dc microgrids require expensive converters to connect to the ac power network. As a result hybrid ac/dc microgrids are gaining more attention as it combines the advantages of both ac and dc microgrids such as direct integration of ac and dc systems with minimum number of conversions which increases the efficiency by reducing energy losses. Although dc electric systems offer many advantages such as no synchronization and no reactive power, successful implementation of dc systems requires appropriate protection strategies. One unique protection challenge brought by the dc systems is dc arc faults. A dc arc fault is generated when there is a gap in the conductor due to insulation degradation and current is used to bridge the gap, resulting in an arc with very high temperature. Such a fault if it goes undetected and is not extinguished can cause damage to the entire system and cause fires. The purpose of the research is to study the effect of the dc arc fault at different locations in the hybrid ac/dc microgrid and provide insight on the reliability of the grid components when it is impacted by arc faults at various locations in the grid. The impact of dc arc fault at different locations on the performance of the PV array, wind generation, and constant power loads (CPL) interfaced with dc/dc converters is studied. MATLAB/Simulink is used to model the hybrid ac/dc microgrid and arc fault.

  16. Model investigation of inlet plenum flow straightening techniques for altitude test facility

    NASA Technical Reports Server (NTRS)

    Riddlebaugh, S. M.; Linke, H. G.

    1976-01-01

    An investigation was conducted to evaluate and improve the quality of the airflow to be supplied to the engine in altitude test chambers 3 and 4 of the Propulsion Systems Laboratory at the Lewis Research Center. One-twentieth-scale models of the inlet plenum chamber of the two test chambers were used in the investigation to minimize time and cost. It was possible to reduce the velocity spread in the inlet plenum from approximately 100 m/sec (330 ft/sec) to approximately 10 m/sec (30 ft/sec) through the combined use of flow diverters, multiple spaced screens, flow straighteners, and turning vanes.

  17. Design of Distributed Controllers Seeking Optimal Power Flow Solutions under Communication Constraints: Preprint

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

    Dall'Anese, Emiliano; Simonetto, Andrea; Dhople, Sairaj

    This paper focuses on power distribution networks featuring inverter-interfaced distributed energy resources (DERs), and develops feedback controllers that drive the DER output powers to solutions of time-varying AC optimal power flow (OPF) problems. Control synthesis is grounded on primal-dual-type methods for regularized Lagrangian functions, as well as linear approximations of the AC power-flow equations. Convergence and OPF-solution-tracking capabilities are established while acknowledging: i) communication-packet losses, and ii) partial updates of control signals. The latter case is particularly relevant since it enables asynchronous operation of the controllers where DER setpoints are updated at a fast time scale based on local voltagemore » measurements, and information on the network state is utilized if and when available, based on communication constraints. As an application, the paper considers distribution systems with high photovoltaic integration, and demonstrates that the proposed framework provides fast voltage-regulation capabilities, while enabling the near real-time pursuit of solutions of AC OPF problems.« less

  18. The study of stiffness modulus values for AC-WC pavement

    NASA Astrophysics Data System (ADS)

    Lubis, AS; Muis, Z. A.; Iskandar, T. D.

    2018-02-01

    One of the parameters of the asphalt mixture in order for the strength and durability to be achieved as required is the stress-and-strain showing the stiffness of a material. Stiffness modulus is a very necessary factor that will affect the performance of asphalt pavements. If the stiffness modulus value decreases there will be a cause of aging asphalt pavement crack easily when receiving a heavy load. The high stiffness modulus asphalt concrete causes more stiff and resistant to bending. The stiffness modulus value of an asphalt mixture material can be obtained from the theoretical (indirect methods) and laboratory test results (direct methods). For the indirect methods used Brown & Brunton method, and Shell Bitumen method; while for the direct methods used the UMATTA tool. This study aims to determine stiffness modulus values for AC-WC pavement. The tests were conducted in laboratory that used 3 methods, i.e. Brown & Brunton Method, Shell Bitumen Method and Marshall Test as a substitute tool for the UMATTA tool. Hotmix asphalt made from type AC-WC with pen 60/70 using a mixture of optimum bitumen content was 5.84% with a standard temperature variation was 60°C and several variations of temperature that were 30, 40, 50, 70 and 80°C. The stiffness modulus value results obtained from Brown & Brunton Method, Shell Bitumen Method and Marshall Test which were 1374,93 Mpa, 235,45 Mpa dan 254,96 Mpa. The stiffness modulus value decreases with increasing temperature of the concrete asphalt. The stiffness modulus value from the Bitumen Shell method and the Marshall Test has a relatively similar value.The stiffness modulus value from the Brown & Brunton method is greater than the Bitumen Shell method and the Marshall Test, but can not measure the stiffness modulus value at temperature above 80°C.

  19. A Gastric Glycoform of MUC5AC Is a Biomarker of Mucinous Cysts of the Pancreas

    PubMed Central

    Sinha, Jessica; Cao, Zheng; Dai, Jianliang; Tang, Huiyuan; Partyka, Katie; Hostetter, Galen; Simeone, Diane M.; Feng, Ziding; Allen, Peter J.; Brand, Randall E.; Haab, Brian B.

    2016-01-01

    Molecular indicators to specify the risk posed by a pancreatic cyst would benefit patients. Previously we showed that most cancer-precursor cysts, termed mucinous cysts, produce abnormal glycoforms of the proteins MUC5AC and endorepellin. Here we sought to validate the glycoforms as a biomarker of mucinous cysts and to specify the oligosaccharide linkages that characterize MUC5AC. We hypothesized that mucinous cysts secrete MUC5AC displaying terminal N-acetylglucosamine (GlcNAc) in either alpha or beta linkage. We used antibody-lectin sandwich assays to detect glycoforms of MUC5AC and endorepellin in cyst fluid samples from three independent cohorts of 49, 32, and 66 patients, and we used monoclonal antibodies to test for terminal, alpha-linked GlcNAc and the enzyme that produces it. A biomarker panel comprising the previously-identified glycoforms of MUC5AC and endorepellin gave 96%, 96%, and 87% accuracy for identifying mucinous cysts in the three cohorts with an average sensitivity of 92% and an average specificity of 94%. Glycan analysis showed that MUC5AC produced by a subset of mucinous cysts displays terminal alpha-GlcNAc, a motif expressed in stomach glands. The alpha-linked glycoform of MUC5AC was unique to intraductal papillary mucinous neoplasms (IPMN), whereas terminal beta-linked GlcNAc was increased in both IPMNs and mucinous cystic neoplasms (MCN). The enzyme that synthesizes alpha-GlcNAc, A4GNT, was expressed in the epithelia of mucinous cysts that expressed alpha-GlcNAc, especially in regions with high-grade dysplasia. Thus IPMNs secrete a gastric glycoform of MUC5AC that displays terminal alpha-GlcNAc, and the combined alpha-GlcNAc and beta-GlcNAc glycoforms form an accurate biomarker of mucinous cysts. PMID:27992432

  20. Frequency-dependent tACS modulation of BOLD signal during rhythmic visual stimulation.

    PubMed

    Chai, Yuhui; Sheng, Jingwei; Bandettini, Peter A; Gao, Jia-Hong

    2018-05-01

    Transcranial alternating current stimulation (tACS) has emerged as a promising tool for modulating cortical oscillations. In previous electroencephalogram (EEG) studies, tACS has been found to modulate brain oscillatory activity in a frequency-specific manner. However, the spatial distribution and hemodynamic response for this modulation remains poorly understood. Functional magnetic resonance imaging (fMRI) has the advantage of measuring neuronal activity in regions not only below the tACS electrodes but also across the whole brain with high spatial resolution. Here, we measured fMRI signal while applying tACS to modulate rhythmic visual activity. During fMRI acquisition, tACS at different frequencies (4, 8, 16, and 32 Hz) was applied along with visual flicker stimulation at 8 and 16 Hz. We analyzed the blood-oxygen-level-dependent (BOLD) signal difference between tACS-ON vs tACS-OFF, and different frequency combinations (e.g., 4 Hz tACS, 8 Hz flicker vs 8 Hz tACS, 8 Hz flicker). We observed significant tACS modulation effects on BOLD responses when the tACS frequency matched the visual flicker frequency or the second harmonic frequency. The main effects were predominantly seen in regions that were activated by the visual task and targeted by the tACS current distribution. These findings bridge different scientific domains of tACS research and demonstrate that fMRI could localize the tACS effect on stimulus-induced brain rhythms, which could lead to a new approach for understanding the high-level cognitive process shaped by the ongoing oscillatory signal. © 2018 Wiley Periodicals, Inc.

  1. Apple MdACS6 Regulates Ethylene Biosynthesis During Fruit Development Involving Ethylene-Responsive Factor.

    PubMed

    Li, Tong; Tan, Dongmei; Liu, Zhi; Jiang, Zhongyu; Wei, Yun; Zhang, Lichao; Li, Xinyue; Yuan, Hui; Wang, Aide

    2015-10-01

    Ethylene biosynthesis in plants involves different 1-aminocyclopropane-1-carboxylic acid synthase (ACS) genes. The regulation of each ACS gene during fruit development is unclear. Here, we characterized another apple (Malus×domestica) ACS gene, MdACS6. The transcript of MdACS6 was observed not only in fruits but also in other tissues. During fruit development, MdACS6 was initiated at a much earlier stage, whereas MdACS3a and MdACS1 began to be expressed at 35 d before harvest and immediateley after harvest, respectively. Moreover, the enzyme activity of MdACS6 was significantly lower than that of MdACS3a and MdACS1, accounting for the low ethylene biosynthesis in young fruits. Overexpression of MdACS6 (MdACS6-OE) by transient assay in apple showed enhanced ethylene production, and MdACS3a was induced in MdACS6-OE fruits but not in control fruits. In MdACS6 apple fruits silenced by the virus-induced gene silencing (VIGS) system (MdACS6-AN), neither ethylene production nor MdACS3a transcript was detectable. In order to explore the mechanism through which MdACS3a was induced in MdACS6-OE fruits, we investigated the expression of apple ethylene-responsive factor (ERF) genes. The results showed that the expression of MdERF2 was induced in MdACS6-OE fruits and inhibited in MdACS6-AN fruits. Yeast one-hybrid assay showed that MdERF2 protein could bind to the promoter of MdACS3a. Moreover, down-regulation of MdERF2 in apple flesh callus led to a decrease of MdACS3a expression, demonstrating the regulation of MdERF2 on MdACS3a. The mechanism through which MdACS6 regulates the action of MdACS3a was discussed. © The Author 2015. Published by Oxford University Press on behalf of Japanese Society of Plant Physiologists. All rights reserved. For permissions, please email: journals.permissions@oup.com.

  2. Counter-Flow Cooling Tower Test Cell

    NASA Astrophysics Data System (ADS)

    Dvořák, Lukáš; Nožička, Jiří

    2014-03-01

    The article contains a design of a functional experimental model of a cross-flow mechanical draft cooling tower and the results and outcomes of measurements. This device is primarily used for measuring performance characteristics of cooling fills, but with a simple rebuild, it can be used for measuring other thermodynamic processes that take part in so-called wet cooling. The main advantages of the particular test cell lie in the accuracy, size, and the possibility of changing the water distribution level. This feature is very useful for measurements of fills of different heights without the influence of the spray and rain zone. The functionality of this test cell has been verified experimentally during assembly, and data from the measurement of common film cooling fills have been compared against the results taken from another experimental line. For the purpose of evaluating the data gathered, computational scripts were created in the MATLAB numerical computing environment. The first script is for exact calculation of the thermal balance of the model, and the second is for determining Merkel's number via Chebyshev's method.

  3. Characterizing superconducting thin films using AC Magnetic Susceptibility

    NASA Astrophysics Data System (ADS)

    Mahoney, C. H.; Porzio, J.; Sullivan, M. C.

    2014-03-01

    We present our work on using ac magnetic susceptibility to determine the critical temperature of superconducting thin films. In ac magnetic susceptibility, the thin film is placed between two coils. One coil carries an ac signal, creating a varying external magnetic field. We measure the voltage induced in the pick-up coil on the opposite side of the sample and measure how the sample magnetization changes as the temperature changes. We will present our work to use ac susceptibility to determine critical temperature and superconducting volume fraction. Using our own analysis program, we are able to accurately locate the critical temperatures of the samples and determine the transition width. For the superconducting volume fraction, we etch samples in order to control the thicknesses of the sample and measure how much of the material grown on the surface is superconducting. Supported by NFS grant DMR-1305637.

  4. Concentrations of MUC16 and MUC5AC using three tear collection methods

    PubMed Central

    Nichols, Jason J.

    2017-01-01

    Purpose To determine the optimal tear collection method for analysis of ocular surface mucins MUC5AC and MUC16. Methods Fifteen subjects without ocular surface disease were recruited. Subjects presented for tear collection on three separate days for three different tear collection methods with the order of method randomized. Methods used to collect tears from right and left eyes included Schirmer’s strip, basal tear collection, and flush tear collection. All samples from the right eyes were individually analyzed for MUC5AC whereas the left eye samples were individually analyzed for MUC16. For each individual sample, 10 μg of protein were loaded per lane into a 1% (w/v) agarose gel and run in electrophoresis buffer for 2 h. After overnight capillary transfer, membranes were incubated with either MUC5AC antibody CLH2 or MUC16 antibody OC125 for western blot analysis. Blots were developed with enhanced chemiluminescence (ECL) and signals captured with the Odyssey Fc (LI-COR). The relative amounts of MUC5AC and MUC16 were quantified with densitometry using software and compared for statistically significant differences between tear collection methods using the Kruskal–Wallis test in SPSS 22 and GraphPad Prism 7.02. Dunn’s multiple comparisons test was used for pairwise post-hoc comparisons. Results Samples containing less than 10 μg of total protein were not used for analysis which left eight samples (out of 45) unusable. The calculated MUC5AC median signal intensities from Schirmer’s strip, basal tears, and flush tears were 2.86 (n = 15, the interquartile range [IQR] = 2.54–3.21), 1.65 (n = 14, IQR = 1.34–3.1), and 1.67 (n = 9, IQR = 1.42–1.72), respectively (H = 9.5, p = 0.009). Post-hoc pairwise comparisons showed a statistically significant difference between Schirmer’s strip and flush tears (p = 0.01). The calculated MUC16 median signal intensities from Schirmer’s strip, basal tears, and flush tears were 1.88 (n = 14, IQR = 1.43–2.61), 5

  5. Introducing high performance distributed logging service for ACS

    NASA Astrophysics Data System (ADS)

    Avarias, Jorge A.; López, Joao S.; Maureira, Cristián; Sommer, Heiko; Chiozzi, Gianluca

    2010-07-01

    The ALMA Common Software (ACS) is a software framework that provides the infrastructure for the Atacama Large Millimeter Array and other projects. ACS, based on CORBA, offers basic services and common design patterns for distributed software. Every properly built system needs to be able to log status and error information. Logging in a single computer scenario can be as easy as using fprintf statements. However, in a distributed system, it must provide a way to centralize all logging data in a single place without overloading the network nor complicating the applications. ACS provides a complete logging service infrastructure in which every log has an associated priority and timestamp, allowing filtering at different levels of the system (application, service and clients). Currently the ACS logging service uses an implementation of the CORBA Telecom Log Service in a customized way, using only a minimal subset of the features provided by the standard. The most relevant feature used by ACS is the ability to treat the logs as event data that gets distributed over the network in a publisher-subscriber paradigm. For this purpose the CORBA Notification Service, which is resource intensive, is used. On the other hand, the Data Distribution Service (DDS) provides an alternative standard for publisher-subscriber communication for real-time systems, offering better performance and featuring decentralized message processing. The current document describes how the new high performance logging service of ACS has been modeled and developed using DDS, replacing the Telecom Log Service. Benefits and drawbacks are analyzed. A benchmark is presented comparing the differences between the implementations.

  6. The metallic sphere in a uniform ac magnetic field: A simple and precise experiment for exploring eddy currents and non-destructive testing

    NASA Astrophysics Data System (ADS)

    Honke, Michael L.; Bidinosti, Christopher P.

    2018-06-01

    We describe a very simple experiment that utilizes standard laboratory equipment to measure the electromagnetic response of a metallic sphere exposed to a uniform ac magnetic field. Measurements were made for a variety of non-magnetic and magnetic metals, and in all cases the results fit very well with theory over the four orders of frequency (25 Hz to 102 kHz) explored here. Precise values of magnetic permeability and electrical conductivity can be extracted from fits to the data given the sphere radius only. The same apparatus is also used to explore the effects of geometry on eddy current generation as well as to demonstrate non-destructive testing through measurements on coins of different composition.

  7. Particle Line Assembly/Patterning by Microfluidic AC Electroosmosis

    NASA Astrophysics Data System (ADS)

    Lian, Meng; Islam, Nazmul; Wu, Jie

    2006-04-01

    Recently AC electroosmosis has attracted research interests worldwide. This paper is the first to investigate particle line assembly/patterning by AC electroosmosis. Since AC electroosmotic force has no dependence on particle sizes, this technique is particularly useful for manipulating nanoscale substance, and hopefully constructs functional nanoscale devices. Two types of ACEO devices, in the configurations of planar interdigitated electrodes and parallel plate electrodes, and a biased ACEO technique are studied, which provides added flexibility in particle manipulation and line assembly. The paper also investigates the effects of electrical field distributions on generating microflows for particle assembly. The results are corroborated experimentally.

  8. Interpretation of Flow Logs from Nevada Test Site Boreholes to Estimate Hydraulic Conductivity Using Numerical Simulations Constrained by Single-Well Aquifer Tests

    USGS Publications Warehouse

    Garcia, C. Amanda; Halford, Keith J.; Laczniak, Randell J.

    2010-01-01

    Hydraulic conductivities of volcanic and carbonate lithologic units at the Nevada Test Site were estimated from flow logs and aquifer-test data. Borehole flow and drawdown were integrated and interpreted using a radial, axisymmetric flow model, AnalyzeHOLE. This integrated approach is used because complex well completions and heterogeneous aquifers and confining units produce vertical flow in the annular space and aquifers adjacent to the wellbore. AnalyzeHOLE simulates vertical flow, in addition to horizontal flow, which accounts for converging flow toward screen ends and diverging flow toward transmissive intervals. Simulated aquifers and confining units uniformly are subdivided by depth into intervals in which the hydraulic conductivity is estimated with the Parameter ESTimation (PEST) software. Between 50 and 150 hydraulic-conductivity parameters were estimated by minimizing weighted differences between simulated and measured flow and drawdown. Transmissivity estimates from single-well or multiple-well aquifer tests were used to constrain estimates of hydraulic conductivity. The distribution of hydraulic conductivity within each lithology had a minimum variance because estimates were constrained with Tikhonov regularization. AnalyzeHOLE simulated hydraulic-conductivity estimates for lithologic units across screened and cased intervals are as much as 100 times less than those estimated using proportional flow-log analyses applied across screened intervals only. Smaller estimates of hydraulic conductivity for individual lithologic units are simulated because sections of the unit behind cased intervals of the wellbore are not assumed to be impermeable, and therefore, can contribute flow to the wellbore. Simulated hydraulic-conductivity estimates vary by more than three orders of magnitude across a lithologic unit, indicating a high degree of heterogeneity in volcanic and carbonate-rock units. The higher water transmitting potential of carbonate-rock units relative

  9. Addressing Theory and Performance Enhancements for the Independent Sustain and Address AC Plasma Display

    NASA Astrophysics Data System (ADS)

    Warren, Kevin Wilson

    The Independent Sustain and Address (ISA) AC plasma panel is a flat, flicker-free, gas discharge type of display device. This display technology promises to reduce both the cost of manufacturing and operation of AC plasma displays. The ISA technology uses a vastly different mechanism to change the state of the display pixels than the standard AC plasma technology. This addressing mechanism is an exploitation of some of the natural characteristics associated with the plasma that can form during strong gas discharges. This thesis presents detailed data from experiments that were designed to evaluate and test the effectiveness of this mechanism. Through these experiments, the theory that the addressing methodology is based upon is developed and evaluated. These experiments show that the address margin windows for this technology are very large, minimally two to three times larger than the address margins for the standard XY AC plasma addressing techniques. New capabilities are also described, such as global brightness control for the ISA technology and a technique for increasing the addressing rate. These advances were designed into working prototypes and transferred to industry where there are currently commercial products available based upon these advances. A technique for implementing gray scale using some of these advances is also proposed.

  10. Directional flow induced by synchronized longitudinal and zeta-potential controlling AC-electrical fields.

    PubMed

    van der Wouden, E J; Hermes, D C; Gardeniers, J G E; van den Berg, A

    2006-10-01

    Electroosmotic flow (EOF) in a microchannel can be controlled by electronic control of the surface charge using an electrode embedded in the wall of the channel. By setting a voltage to the electrode, the zeta-potential at the wall can be changed locally. Thus, the electrode acts as a "gate" for liquid flow, in analogy with a gate in a field-effect transistor. In this paper we will show three aspects of a Field Effect Flow Control (FEFC) structure. We demonstrate the induction of directional flow by the synchronized switching of the gate potential with the channel axial potential. The advantage of this procedure is that potential gas formation by electrolysis at the electrodes that provide the axial electric field is suppressed at sufficiently large switching frequencies, while the direction and magnitude of the EOF can be maintained. Furthermore we will give an analysis of the time constants involved in the charging of the insulator, and thus the switching of the zeta potential, in order to predict the maximum operating frequency. For this purpose an equivalent electrical circuit is presented and analyzed. It is shown that in order to accurately describe the charging dynamics and pH dependency the traditionally used three capacitor model should be expanded with an element describing the buffer capacitance of the silica wall surface.

  11. Dielectrophoretic concentration of particles under electrokinetic flow

    DOEpatents

    Miles, Robin R.; Bettencourt, Kerry A.; Fuller, Christopher K.

    2004-09-07

    The use of dielectrophoresis to collect particles under the conditions of electrokinetically-driven flow. Dielectrophortic concentration of particles under electrokinetic flow is accomplished by interdigitated electrodes patterned on an inner surface of a microfluid channel, a DC voltage is applied across the ends to the channel, and an AC voltage is applied across the electrodes, and particles swept down the channel electrokinetically are trapped within the field established by the electrodes. The particles can be released when the voltage to the electrodes is released.

  12. Effect of a single injection of autologous conditioned serum (ACS) on tendon healing in equine naturally occurring tendinopathies.

    PubMed

    Geburek, Florian; Lietzau, Maren; Beineke, Andreas; Rohn, Karl; Stadler, Peter M

    2015-06-26

    . Intralesional ACS treatment might decrease proliferation of tenocytes 5 weeks after treatment and increase their differentiation as demonstrated by elevated collagen type I expression in the remodelling phase. Potential enhancement of these effects by repeated injections should be tested in future controlled clinical investigations.

  13. Single element injector cold flow testing for STME swirl coaxial injector element design

    NASA Technical Reports Server (NTRS)

    Hulka, J.; Schneider, J. A.

    1993-01-01

    An oxidizer-swirled coaxial element injector is being investigated for application in the Space Transportation Main Engine (STME). Single element cold flow experiments were conducted to provide characterization of the STME injector element for future analysis, design, and optimization. All tests were conducted to quiescent, ambient backpressure conditions. Spray angle, circumferential spray uniformity, dropsize, and dropsize distribution were measured in water-only and water/nitrogen flows. Rupe mixing efficiency was measured using water/sucrose solution flows with a large grid patternator for simple comparative evaluation of mixing. Factorial designs of experiment were used for statistical evaluation of injector geometrical design features and propellant flow conditions on mixing and atomization. Increasing the free swirl angle of the liquid oxidizer had the greatest influence on increasing the mixing efficiency. The addition of gas assistance had the most significant effect on reducing oxidizer droplet size parameters and increasing droplet size distribution. Increasing the oxidizer injection velocity had the greatest influence for reducing oxidizer droplet size parameters and increasing size distribution for non-gas assisted flows. Single element and multi-element subscale hot fire testing are recommended to verify optimized designs before committing to the STME design.

  14. Understanding the Geometry of Connected Fracture Flow with Multiperiod Oscillatory Hydraulic Tests.

    PubMed

    Sayler, Claire; Cardiff, Michael; Fort, Michael D

    2018-03-01

    An understanding of the spatial and hydraulic properties of fast preferential flow pathways in the subsurface is necessary in applications ranging from contaminant fate and transport modeling to design of energy extraction systems. One method for the characterization of fracture properties over interwellbore scales is Multiperiod Oscillatory Hydraulic (MOH) testing, in which the aquifer response to oscillatory pressure stimulations is observed. MOH tests were conducted on isolated intervals of wells in siliciclastic and carbonate aquifers in southern Wisconsin. The goal was to characterize the spatial properties of discrete fractures over interwellbore scales. MOH tests were conducted on two discrete fractured intervals intersecting two boreholes at one field site, and a nest of three piezometers at another field site. Fracture diffusivity estimates were obtained using analytical solutions that relate diffusivity to observed phase lag and amplitude decay. In addition, MOH tests were used to investigate the spatial extent of flow using different conceptual models of fracture geometry. Results indicated that fracture geometry at both field sites can be approximated by permeable two-dimensional fracture planes, oriented near-horizontally at one site, and near-vertically at the other. The technique used on MOH field data to characterize fracture geometry shows promise in revealing fracture network characteristics important to groundwater flow and transport. © 2017, National Ground Water Association.

  15. Inlet flow test calibration for a small axial compressor rig. Part 2: CFD compared with experimental results

    NASA Technical Reports Server (NTRS)

    Miller, D. P.; Prahst, P. S.

    1995-01-01

    An axial compressor test rig has been designed for the operation of small turbomachines. A flow test was run to calibrate and determine the source and magnitudes of the loss mechanisms in the compressor inlet for a highly loaded two-stage axial compressor test. Several flow conditions and inlet guide vane (IGV) angle settings were established, for which detailed surveys were completed. Boundary layer bleed was also provided along the casing of the inlet behind the support struts and ahead of the IGV. Several computational fluid dynamics (CFD) calculations were made for selected flow conditions established during the test. Good agreement between the CFD and test data were obtained for these test conditions.

  16. New Insulation Constructions for Aerospace Wiring Applications. Volume 1. Testing and Evaluation

    DTIC Science & Technology

    1991-06-01

    28 S.3.2 CORONA INCEPTION AND EXTINCIION VOLTAGES 5 - 33 5.3.2.. AC CORONA INCEPTION AND EXTINCTION VOLTAGES 5...... - 33 5.3.2.2 DC CORONA ...SETUP ....... .. 5 - 27 5.10 DIELECTRIC CONSTANT TEST RESULTS .......... .. 5 - 32 5.11 AC CORONA INCEPTION AND EXTINCTION TEST, 22 AWG, 8.6 MIL WALL...AIRFRAME WIRE ... .......... 5 - 39 5.12 AC CORONA INCEPTION AND EXTINCTION TEST, 22 AWG, 5.8 MIL WALL, HOOK UP WIRE .... ........... 5 - 40 5.13 AC

  17. Regulation of Renewable Energy Sources to Optimal Power Flow Solutions Using ADMM

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

    Dall-Anese, Emiliano; Zhang, Yijian; Hong, Mingyi

    This paper considers power distribution systems featuring renewable energy sources (RESs), and develops a distributed optimization method to steer the RES output powers to solutions of AC optimal power flow (OPF) problems. The design of the proposed method leverages suitable linear approximations of the AC-power flow equations, and is based on the Alternating Direction Method of Multipliers (ADMM). Convergence of the RES-inverter output powers to solutions of the OPF problem is established under suitable conditions on the stepsize as well as mismatches between the commanded setpoints and actual RES output powers. In a broad sense, the methods and results proposedmore » here are also applicable to other distributed optimization problem setups with ADMM and inexact dual updates.« less

  18. AC Coupled Interconnect for Low Power Spaceborne Electronics

    DTIC Science & Technology

    2006-09-30

    Final Report 3. DATES COVERED (From - To) 20/05/2003 to 30/09/2006 4. TITLE AND SUBTITLE AC COUPLED INTERCONNECT FOR LOW POWER SPACEBORNE...14. ABSTRACT The primary objective of this effort was to establish that AC Coupled Interconnect could be used to create multiple solutions to...

  19. Design, Validation, and Testing of a Hot-Film Anemometer for Hypersonic Flow

    NASA Astrophysics Data System (ADS)

    Sheplak, Mark

    The application of constant-temperature hot-film anemometry to hypersonic flow has been reviewed and extended in this thesis. The objective of this investigation was to develop a measurement tool capable of yielding continuous, high-bandwidth, quantitative, normal mass-flux and total -temperature measurements in moderate-enthalpy environments. This research has produced a probe design that represents a significant advancement over existing designs, offering the following improvements: (1) a five-fold increase in bandwidth; (2) true stagnation-line sensor placement; (3) a two order-of-magnitude decrease in sensor volume; and (4) over a 70% increase in maximum film temperature. These improvements were achieved through substrate design, sensor placement, the use of high-temperature materials, and state -of-the-art microphotolithographic fabrication techniques. The experimental study to characterize the probe was performed in four different hypersonic wind tunnels at NASA-Langley Research Center. The initial test consisted of traversing the hot film through a Mach 6, flat-plate, turbulent boundary layer in air. The detailed static-calibration measurements that followed were performed in two different hypersonic flows: a Mach 11 helium flow and Mach 6 air flow. The final test of this thesis consisted of traversing the probe through the Mach 6 wake of a 70^ circ blunt body. The goal of this test was to determine the state (i.e., laminar or turbulent) of the wake. These studies indicate that substrate conduction effects result in instrumentation characteristics that prevent the hot-film anemometer from being used as a quantitative tool. The extension of this technique to providing quantitative information is dependent upon the development of lower thermal-conductivity substrate materials. However, the probe durability, absence of strain gauging, and high bandwidth represent significant improvements over the hot-wire technique for making qualitative measurements. Potential

  20. Facility Activation and Characterization for IPD Oxidizer Turbopump Cold-Flow Testing at NASA Stennis Space Center

    NASA Technical Reports Server (NTRS)

    Sass, J. P.; Raines, N. G.; Farner, B. R.; Ryan, H. M.

    2004-01-01

    The Integrated Powerhead Demonstrator (IPD) is a 250K lbf (1.1 MN) thrust cryogenic hydrogen/oxygen engine technology demonstrator that utilizes a full flow staged combustion engine cycle. The Integrated Powerhead Demonstrator (IPD) is part of NASA's Next Generation Launch Technology (NGLT) program, which seeks to provide safe, dependable, cost-cutting technologies for future space launch systems. The project also is part of the Department of Defense's Integrated High Payoff Rocket Propulsion Technology (IHPRPT) program, which seeks to increase the performance and capability of today s state-of-the-art rocket propulsion systems while decreasing costs associated with military and commercial access to space. The primary industry participants include Boeing-Rocketdyne and GenCorp Aerojet. The intended full flow engine cycle is a key component in achieving all of the aforementioned goals. The IPD Program achieved a major milestone with the successful completion of the IPD Oxidizer Turbopump (OTP) cold-flow test project at the NASA John C. Stennis Space Center (SSC) E-1 test facility in November 2001. A total of 11 IPD OTP cold-flow tests were completed. Following an overview of the NASA SSC E-1 test facility, this paper addresses the facility aspects pertaining to the activation and the cold-flow testing of the IPD OTP. In addition, some of the facility challenges encountered during the test project are addressed.

  1. [Ru/AC catalyzed ozonation of recalcitrant organic compounds].

    PubMed

    Wang, Jian-Bing; Hou, Shao-Pei; Zhou, Yun-Rui; Zhu, Wan-Peng; He, Xu-Wen

    2009-09-15

    Ozonation and Ru/AC catalyzed ozonation of dimethyl phthalate (DMP), phenols and disinfection by-products precursors were studied. It shows that Ru/AC catalyst can obviously enhance the mineralization of organic compounds. In the degradation of DMP, TOC removal was 28.84% by ozonation alone while it was 66.13% by catalytic ozonation. In the oxidation of 23 kinds of phenols, TOC removals were 9.57%-56.08% by ozonation alone while they were 41.81%-82.32% by catalytic ozonation. Compared to ozonation alone, Ru/AC catalyzed ozonation was more effective for the reduction of disinfection by-products formation potentials in source water. The reduction of haloacetic acids formation potentials was more obvious than thichlomethane formation potentials. After the treatment by catalytic ozonation, the haloacetic acids formation potentials decreased from 144.02 microg/L to 58.50 microg/L, which was below the standard value of EPA. However ozonation alone could not make it reach the standard. The treatments of source water by BAC, O3 + BAC, O3/AC + BAC and Ru/AC + O3 + BAC were also studied. In the four processes, TOC removal was 3.80%, 20.14%, 27.45% and 48.30% respectively, COD removal was 4.37%, 27.22%, 39.91% and 50.00% respectively, UV254 removal was 8.16%, 62.24%, 67.03% and 84.95% respectively. Ru/AC + O3 + BAC process is more effective than the other processes for the removal of TOC, COD and UV254 and no ruthenium leaching observed in the solution. It is a promising process for the treatment of micro polluted source water.

  2. Methods for Addressing Missing Data with Applications from ACS Exams

    ERIC Educational Resources Information Center

    Brandriet, Alexandra; Holme, Thomas

    2015-01-01

    As part of the ACS Examinations Institute (ACS-EI) national norming process, student performance data sets are collected from professors at colleges and universities from around the United States. Because the data sets are collected on a volunteer basis, the ACS-EI often receives data sets with only students' total scores and without the students'…

  3. Model-Invariant Hybrid Computations of Separated Flows for RCA Standard Test Cases

    NASA Technical Reports Server (NTRS)

    Woodruff, Stephen

    2016-01-01

    NASA's Revolutionary Computational Aerosciences (RCA) subproject has identified several smooth-body separated flows as standard test cases to emphasize the challenge these flows present for computational methods and their importance to the aerospace community. Results of computations of two of these test cases, the NASA hump and the FAITH experiment, are presented. The computations were performed with the model-invariant hybrid LES-RANS formulation, implemented in the NASA code VULCAN-CFD. The model- invariant formulation employs gradual LES-RANS transitions and compensation for model variation to provide more accurate and efficient hybrid computations. Comparisons revealed that the LES-RANS transitions employed in these computations were sufficiently gradual that the compensating terms were unnecessary. Agreement with experiment was achieved only after reducing the turbulent viscosity to mitigate the effect of numerical dissipation. The stream-wise evolution of peak Reynolds shear stress was employed as a measure of turbulence dynamics in separated flows useful for evaluating computations.

  4. Maximal blood flow acceleration analysis in the early diastolic phase for aortocoronary artery bypass grafts: a new transit-time flow measurement predictor of graft failure following coronary artery bypass grafting.

    PubMed

    Handa, Takemi; Orihashi, Kazumasa; Nishimori, Hideaki; Yamamoto, Masaki

    2016-11-01

    Maximal graft flow acceleration (max df/dt) determined using transit-time flowmetry (TTFM) in the diastolic phase was assessed as a potential predictor of graft failure for aortocoronary artery (AC) bypass grafts in coronary artery bypass patients. Max df/dt was retrospectively measured in 114 aortocoronary artery bypass grafts. TTFM data were fitted to a 9-polynomial curve, which was derived from the first-derivative curve, to measure max df/dt (9-polynomial max df/dt). Abnormal TTFM was defined as a mean flow of <15 ml/min, a pulsatility index of >5 or a diastolic filling ratio of <50 %. Postoperative assessments were routinely performed by coronary artery angiography (CAG) at 1 year after surgery. Using TTFM, 68 grafts were normal, 4 of which were failing on CAG, and 46 grafts were abnormal, 21 of which were failing on CAG. 9-polynomial max df/dt was significantly lower in abnormal TTFM/failing by the CAG group compared with abnormal TTFM/patent by the CAG group (1.08 ± 0.89 vs. 2.05 ± 1.51 ml/s(2), respectively; P < 0.01, Mann-Whitney U test, Holm adjustment). TTFM 9-polynomial max df/dt in the early diastolic phase may be a promising predictor of future graft failure for AC bypass grafts, particularly in abnormal TTFM grafts.

  5. Diagnostics of the Fermilab Tevatron using an AC dipole

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

    Miyamoto, Ryoichi

    2008-08-01

    The Fermilab Tevatron is currently the world's highest energy colliding beam facility. Its counter-rotating proton and antiproton beams collide at 2 TeV center-of-mass. Delivery of such intense beam fluxes to experiments has required improved knowledge of the Tevatron's beam optical lattice. An oscillating dipole magnet, referred to as an AC dipole, is one of such a tool to non-destructively assess the optical properties of the synchrotron. We discusses development of an AC dipole system for the Tevatron, a fast-oscillating (f ~ 20 kHz) dipole magnet which can be adiabatically turned on and off to establish sustained coherent oscillations of themore » beam particles without affecting the transverse emittance. By utilizing an existing magnet and a higher power audio amplifier, the cost of the Tevatron AC dipole system became relatively inexpensive. We discuss corrections which must be applied to the driven oscillation measurements to obtain the proper interpretation of beam optical parameters from AC dipole studies. After successful operations of the Tevatron AC dipole system, AC dipole systems, similar to that in the Tevatron, will be build for the CERN LHC. We present several measurements of linear optical parameters (beta function and phase advance) for the Tevatron, as well as studies of non-linear perturbations from sextupole and octupole elements.« less

  6. A new therapeutic approach for type 1 diabetes: rationale for GNbAC1 an anti-HERV-W-Env monoclonal antibody.

    PubMed

    Curtin, Francois; Bernard, Corinne; Levet, Sandrine; Perron, Hervé; Porchet, Hervé; Médina, Julie; Malpass, Sam; Lloyd, David; Simpson, Richard

    2018-05-10

    We describe a newly identified therapeutic target for type 1 diabetes: an envelope protein of endogenous retroviral origin called Human Endogenous Retrovirus W Envelope (HERV-W-Env). HERV-W-Env was found to be detected in the blood of around 60% of type 1 diabetes (T1D) patients and is expressed in acinar pancreatic cells of 75% of T1D patients at post-mortem examination. Preclinical experiments showed that this protein displays direct cytotoxicity on human β-islet cells. In vivo HERV-W-Env impairs the insulin and glucose metabolism in transgenic mice expressing HERV-W-Env. GNbAC1, an IgG4 monoclonal antibody has been developed to specifically target HERV-W-Env and to neutralize the effect of HERV-W-Env in vitro and in vivo. GNbAC1 is currently in clinical development for multiple sclerosis and more than 300 subjects have been administered with GNbAC1 so far. GNbAC1 is now tested in T1D in the RAINBOW-T1D study: a randomized placebo controlled study with the objective of showing the safety and pharmacodynamics response of GNbAC1 in patients suffering from T1D with a maximum duration of 4 years. GNbAC1 is tested versus placebo at the dose of 6 mg/kg in 60 patients during 6 repeated administrations during 6 months, a 6-month open-label extension will follow. The primary endpoint will assess safety and secondary endpoints the pharmacodynamic responses to GNbAC1. GNbAC1 targeting HERV-W-Env is currently in clinical development in T1D with the first safety and pharmacodynamic study. If the study results are positive, this may open the door to the development of an innovative non-immunomodulatory disease modifying treatment for T1D. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

  7. Development of a Non-Contact, Inductive Depth Sensor for Free-Surface, Liquid-Metal Flows

    NASA Astrophysics Data System (ADS)

    Bruhaug, Gerrit; Kolemen, Egemen; Fischer, Adam; Hvasta, Mike

    2017-10-01

    This paper details a non-contact based, inductive depth measurement system that can sit behind a layer of steel and measure the depth of the liquid metal flowing over the steel. Free-surface liquid metal depth measurement is usually done with invasive sensors that impact the flow of the liquid metal, or complex external sensors that require lasers and precise alignment. Neither of these methods is suitable for the extreme environment encountered in the diverter region of a nuclear fusion reactor, where liquid metal open channel flows are being investigated for future use. A sensor was developed that used the inductive coupling of a coil to liquid metal to measure the height of the liquid metal present. The sensor was built and tested experimentally, and modeled with finite element modeling software to further understand the physics involved. Future work will attempt to integrate the sensor into the Liquid Metal eXperiment (LMX) at the Princeton Plasma Physics Laboratory for more refined testing. This work was made possible by funding from the Department of Energy for the Summer Undergraduate Laboratory Internship (SULI) program. This work is supported by the US DOE Contract No.DE-AC02-09CH11466.

  8. Ru-Sn/AC for the Aqueous-Phase Reduction of Succinic Acid to 1,4-Butanediol under Continuous Process Conditions

    DOE PAGES

    Vardon, Derek R.; Settle, Amy E.; Vorotnikov, Vassili; ...

    2017-08-18

    Succinic acid is a biomass-derived platform chemical that can be catalytically converted in the aqueous phase to 1,4-butanediol (BDO), a prevalent building block used in the polymer and chemical industries. Despite significant interest, limited work has been reported regarding sustained catalyst performance and stability under continuous aqueous-phase process conditions. As such, this work examines Ru-Sn on activated carbon (AC) for the aqueous-phase conversion of succinic acid to BDO under batch and flow reactor conditions. Initially, powder Ru-Sn catalysts were screened to determine the most effective bimetallic ratio and provide a comparison to other monometallic (Pd, Pt, Ru) and bimetallic (Pt-Sn,more » Pd-Re) catalysts. Batch reactor tests determined that a ~1:1 metal weight ratio of Ru to Sn was effective for producing BDO in high yields, with complete conversion resulting in 82% molar yield. Characterization of the fresh Ru-Sn catalyst suggests that the sequential loading method results in Ru sites that are colocated and surface-enriched with Sn. Postbatch reaction characterization confirmed stable Ru-Sn material properties; however, upon a transition to continuous conditions, significant Ru-Sn/AC deactivation occurred due to stainless steel leaching of Ni that resulted in Ru-Sn metal crystallite restructuring to form discrete Ni-Sn sites. Computational modeling confirmed favorable energetics for Ru-Sn segregation and Ni-Sn formation at submonolayer Sn incorporation. To address stainless steel leaching, reactor walls were treated with an inert silica coating by chemical vapor deposition. With leaching reduced, stable Ru-Sn/AC performance was observed that resulted in a molar yield of 71% BDO and 15% tetrahydrofuran for 96 h of time on stream. Postreaction catalyst characterization confirmed low levels of Ni and Cr deposition, although early-stage islanding of Ni-Sn will likely be problematic for industrially relevant time scales (i.e., thousands of hours

  9. Study of oscillating electroosmotic flows with high temporal and spatial resolution

    NASA Astrophysics Data System (ADS)

    Wang, Guiren; Liu, Xin; Yang, Fang; Wang, Kaige; Bai, Jintao; Qiao, Rui; Zhao, Wei

    2017-11-01

    In AC electrokinetic (EK) flow where solid-fluid interface exists, oscillating electroosmotic flow (OEOF) is an inevitable flow phenomenon. However, few experimental investigations have been reported on instantaneous velocity of OEOF driven by AC electric field. Here, we studied the near-wall velocity of OEOF by Laser-induced Fluorescence Photobleaching Anemometer (LIFPA). For the first time, an up to 3 kHz velocity response of OEOF had been successfully measured experimentally, even though the oscillating velocity was as low as 600 nm/s. It was found that the oscillating velocity decays with forcing frequency ff, as ff- 0.66 . This had never been predicted by any known theoretical investigations. In the investigated range of electric field intensity (EA) , when ff is below 1 kHz, the linear relation between oscillating velocity and EA was observed. Besides, we also found the bulk flow velocity can significantly affect the oscillating velocity of OEOF. This was also newly observed and implied the bulk flow can affect the formation process of electric double layer. This investigation could be crucial for understanding all OEOF-related phenomena and designing OEOF-based micro/nanofluidics systems. The work was supported by NSF (CAREER CBET-0954977, MRI CBET-1040227, CBET-1336004) and NSFC (11672229).

  10. Aragonite coating solutions (ACS) based on artificial seawater

    NASA Astrophysics Data System (ADS)

    Tas, A. Cuneyt

    2015-03-01

    Aragonite (CaCO3, calcium carbonate) is an abundant biomaterial of marine life. It is the dominant inorganic phase of coral reefs, mollusc bivalve shells and the stalactites or stalagmites of geological sediments. Inorganic and initially precipitate-free aragonite coating solutions (ACS) of pH 7.4 were developed in this study to deposit monolayers of aragonite spherules or ooids on biomaterial (e.g., UHMWPE, ultrahigh molecular weight polyethylene) surfaces soaked in ACS at 30 °C. The ACS solutions of this study have been developed for the surface engineering of synthetic biomaterials. The abiotic ACS solutions, enriched with calcium and bicarbonate ions at different concentrations, essentially mimicked the artificial seawater composition and started to deposit aragonite after a long (4 h) incubation period at the tropical sea surface temperature of 30 °C. While numerous techniques for the solution deposition of calcium hydroxyapatite (Ca10(PO4)6(OH)2), of low thermodynamic solubility, on synthetic biomaterials have been demonstrated, procedures related to the solution-based surface deposition of high solubility aragonite remained uncommon. Monolayers of aragonite ooids deposited at 30 °C on UHMWPE substrates soaked in organic-free ACS solutions were found to possess nano-structures similar to the mortar-and-brick-type botryoids observed in biogenic marine shells. Samples were characterized using SEM, XRD, FTIR, ICP-AES and contact angle goniometry.

  11. Simulation of patient flow in multiple healthcare units using process and data mining techniques for model identification.

    PubMed

    Kovalchuk, Sergey V; Funkner, Anastasia A; Metsker, Oleg G; Yakovlev, Aleksey N

    2018-06-01

    An approach to building a hybrid simulation of patient flow is introduced with a combination of data-driven methods for automation of model identification. The approach is described with a conceptual framework and basic methods for combination of different techniques. The implementation of the proposed approach for simulation of the acute coronary syndrome (ACS) was developed and used in an experimental study. A combination of data, text, process mining techniques, and machine learning approaches for the analysis of electronic health records (EHRs) with discrete-event simulation (DES) and queueing theory for the simulation of patient flow was proposed. The performed analysis of EHRs for ACS patients enabled identification of several classes of clinical pathways (CPs) which were used to implement a more realistic simulation of the patient flow. The developed solution was implemented using Python libraries (SimPy, SciPy, and others). The proposed approach enables more a realistic and detailed simulation of the patient flow within a group of related departments. An experimental study shows an improved simulation of patient length of stay for ACS patient flow obtained from EHRs in Almazov National Medical Research Centre in Saint Petersburg, Russia. The proposed approach, methods, and solutions provide a conceptual, methodological, and programming framework for the implementation of a simulation of complex and diverse scenarios within a flow of patients for different purposes: decision making, training, management optimization, and others. Copyright © 2018 Elsevier Inc. All rights reserved.

  12. AC loss, interstrand resistance and mechanical properties of prototype EU DEMO TF conductors up to 30 000 load cycles

    NASA Astrophysics Data System (ADS)

    Yagotintsev, K.; Nijhuis, A.

    2018-07-01

    Two prototype Nb3Sn cable-in-conduit conductors conductors were designed and manufactured for the toroidal field (TF) magnet system of the envisaged European DEMO fusion reactor. The AC loss, contact resistance and mechanical properties of two sample conductors were tested in the Twente Cryogenic Cable Press under cyclic load up to 30 000 cycles. Though both conductors were designed to operate at 82 kA in a background magnetic field of 13.6 T, they reflect different approaches with respect to the magnet winding pack assembly. The first approach is based on react and wind technology while the second is the more common wind and react technology. Each conductor was tested first for AC loss in virgin condition without handling. The impact of Lorentz load during magnet operation was simulated using the cable press. In the press each conductor specimen was subjected to transverse cyclic load up to 30 000 cycles in liquid helium bath at 4.2 K. Here a summary of results for AC loss, contact resistance, conductor deformation, mechanical heat production and conductor stiffness evolution during cycling of the load is presented. Both conductors showed similar mechanical behaviour but quite different AC loss. In comparison with previously tested ITER TF conductors, both DEMO TF conductors possess very low contact resistance resulting in high coupling loss. At the same time, load cycling has limited impact on properties of DEMO TF conductors in comparison with ITER TF conductors.

  13. Analysis of Electrically Induced Swirling Flow of Isotonic Saline in a Mixing Microchannel

    NASA Astrophysics Data System (ADS)

    Hirahara, Shuzo; Tsuruta, Tomoyuki; Matsumoto, Yoshinori; Minamitani, Haruyuki

    We have designed a prototype microfluidic device to mix suspended particles with isotonic saline by use of electrically induced swirling flow in the microchannel. However, the principles underlying microfluidic rotation induced by AC electrodes are not well understood, and the characteristics of the rotation velocity are unpredictable. Furthermore, these properties have not been studied using a highly conductive liquid like isotonic saline, which is an important fluid in the medical and biological fields. The lack of such studies causes uncertainty in the design required for high-performance microfluidic devices. We have examined the electrical rotational properties of the microfluid at an isotonic concentration of saline using computer simulation, and here we show that buoyant flow, which has previously been largely ignored, has a significant effect in channels of 100-μm depth or deeper, and that AC electroosmotic flow is not induced at isotonic saline concentrations.

  14. ac propulsion system for an electric vehicle

    NASA Technical Reports Server (NTRS)

    Geppert, S.

    1980-01-01

    It is pointed out that dc drives will be the logical choice for current production electric vehicles (EV). However, by the mid-80's, there is a good chance that the price and reliability of suitable high-power semiconductors will allow for a competitive ac system. The driving force behind the ac approach is the induction motor, which has specific advantages relative to a dc shunt or series traction motor. These advantages would be an important factor in the case of a vehicle for which low maintenance characteristics are of primary importance. A description of an EV ac propulsion system is provided, taking into account the logic controller, the inverter, the motor, and a two-speed transmission-differential-axle assembly. The main barrier to the employment of the considered propulsion system in EV is not any technical problem, but inverter transistor cost.

  15. Automated Low-Cost Smartphone-Based Lateral Flow Saliva Test Reader for Drugs-of-Abuse Detection

    PubMed Central

    Carrio, Adrian; Sampedro, Carlos; Sanchez-Lopez, Jose Luis; Pimienta, Miguel; Campoy, Pascual

    2015-01-01

    Lateral flow assay tests are nowadays becoming powerful, low-cost diagnostic tools. Obtaining a result is usually subject to visual interpretation of colored areas on the test by a human operator, introducing subjectivity and the possibility of errors in the extraction of the results. While automated test readers providing a result-consistent solution are widely available, they usually lack portability. In this paper, we present a smartphone-based automated reader for drug-of-abuse lateral flow assay tests, consisting of an inexpensive light box and a smartphone device. Test images captured with the smartphone camera are processed in the device using computer vision and machine learning techniques to perform automatic extraction of the results. A deep validation of the system has been carried out showing the high accuracy of the system. The proposed approach, applicable to any line-based or color-based lateral flow test in the market, effectively reduces the manufacturing costs of the reader and makes it portable and massively available while providing accurate, reliable results. PMID:26610513

  16. Automated Low-Cost Smartphone-Based Lateral Flow Saliva Test Reader for Drugs-of-Abuse Detection.

    PubMed

    Carrio, Adrian; Sampedro, Carlos; Sanchez-Lopez, Jose Luis; Pimienta, Miguel; Campoy, Pascual

    2015-11-24

    Lateral flow assay tests are nowadays becoming powerful, low-cost diagnostic tools. Obtaining a result is usually subject to visual interpretation of colored areas on the test by a human operator, introducing subjectivity and the possibility of errors in the extraction of the results. While automated test readers providing a result-consistent solution are widely available, they usually lack portability. In this paper, we present a smartphone-based automated reader for drug-of-abuse lateral flow assay tests, consisting of an inexpensive light box and a smartphone device. Test images captured with the smartphone camera are processed in the device using computer vision and machine learning techniques to perform automatic extraction of the results. A deep validation of the system has been carried out showing the high accuracy of the system. The proposed approach, applicable to any line-based or color-based lateral flow test in the market, effectively reduces the manufacturing costs of the reader and makes it portable and massively available while providing accurate, reliable results.

  17. Space Launch System Base Heating Test: Environments and Base Flow Physics

    NASA Technical Reports Server (NTRS)

    Mehta, Manish; Knox, Kyle S.; Seaford, C. Mark; Dufrene, Aaron T.

    2016-01-01

    The NASA Space Launch System (SLS) vehicle is composed of four RS-25 liquid oxygen-hydrogen rocket engines in the core-stage and two 5-segment solid rocket boosters and as a result six hot supersonic plumes interact within the aft section of the vehicle during flight. Due to the complex nature of rocket plume-induced flows within the launch vehicle base during ascent and a new vehicle configuration, sub-scale wind tunnel testing is required to reduce SLS base convective environment uncertainty and design risk levels. This hot-fire test program was conducted at the CUBRC Large Energy National Shock (LENS) II short-duration test facility to simulate flight from altitudes of 50 kft to 210 kft. The test program is a challenging and innovative effort that has not been attempted in 40+ years for a NASA vehicle. This paper discusses the various trends of base convective heat flux and pressure as a function of altitude at various locations within the core-stage and booster base regions of the two-percent SLS wind tunnel model. In-depth understanding of the base flow physics is presented using the test data, infrared high-speed imaging and theory. The normalized test design environments are compared to various NASA semi-empirical numerical models to determine exceedance and conservatism of the flight scaled test-derived base design environments. Brief discussion of thermal impact to the launch vehicle base components is also presented.

  18. AC Resistance measuring instrument

    DOEpatents

    Hof, Peter J.

    1983-01-01

    An auto-ranging AC resistance measuring instrument for remote measurement of the resistance of an electrical device or circuit connected to the instrument includes a signal generator which generates an AC excitation signal for application to a load, including the device and the transmission line, a monitoring circuit which provides a digitally encoded signal representing the voltage across the load, and a microprocessor which operates under program control to provide an auto-ranging function by which range resistance is connected in circuit with the load to limit the load voltage to an acceptable range for the instrument, and an auto-compensating function by which compensating capacitance is connected in shunt with the range resistance to compensate for the effects of line capacitance. After the auto-ranging and auto-compensation functions are complete, the microprocessor calculates the resistance of the load from the selected range resistance, the excitation signal, and the load voltage signal, and displays of the measured resistance on a digital display of the instrument.

  19. Ratio between serum IL-8 and pepsinogen A/C: a marker for atrophic body gastritis.

    PubMed

    Sanduleanu, S; Bruïne, A D E; Biemond, I; Stridsberg, M; Jonkers, D; Lundqvist, G; Hameeteman, W; Stockbrügger, R W

    2003-02-01

    Elevated serum gastrin and a low pepsinogen A/C ratio are well-recognized markers for atrophic body gastritis (ABG). We have shown that the presence of body atrophy is also associated with elevated serum pro-inflammatory cytokines. This study tested the hypothesis that serum cytokines provide additional information to gastrin and pepsinogens in screening for ABG. Two hundred and twenty-six consecutive patients were investigated on referral for upper gastrointestinal endoscopy: 150 were patients with gastro-oesophageal reflux disease, receiving acid inhibitory medication either with proton pump inhibitors (n = 113) or with histamine2-receptor antagonists (n = 37), and 76 were nontreated controls, who had normal endoscopic findings. Gastric mucosal biopsies were sampled for histological examination (Sydney classification). Serum samples were analyzed for gastrin, chromogranin A (CgA), and pepsinogens A and C by RIA, and for the interleukins (IL)-1beta, IL-6, and IL-8 by ELISA. Subjects with ABG had significantly higher serum gastrin (P < 0.01) and serum CgA (P < 0.01) levels and significantly lower pepsinogen A/C ratios (P < 0.001) than those without ABG. Additionally, serum IL-1beta, IL-6 and, especially, IL-8 levels were significantly higher in the subjects with than in those without ABG (P < 0.0001, for all cytokines). To optimize the detection of body atrophy we defined the ABG index: the ratio between the simultaneously measured IL-8 and pepsinogen A/C. The area under the ROC curve for the ABG index was significantly greater than that for serum gastrin and for serum pepsinogen A/C alone (0.91 +/- 0.029 vs. 0.72 +/- 0.042, and vs. 0.83 +/- 0.031, P = 0.018 and P = 0.049). Using the ABG index at a cut-off value of 1.8 pg mL-1, 91% of the cases were classified correctly. The ratio between serum IL-8 and pepsinogen A/C accurately predicts the presence of ABG. We therefore propose the ABG index as a noninvasive screening test for ABG in population-based studies.

  20. Hot-flow tests of a series of 10-percent-scale turbofan forced mixing nozzles

    NASA Technical Reports Server (NTRS)

    Head, V. L.; Povinelli, L. A.; Gerstenmaier, W. H.

    1984-01-01

    An approximately 1/10-scale model of a mixed-flow exhaust system was tested in a static facility with fully simulated hot-flow cruise and takeoff conditions. Nine mixer geometries with 12 to 24 lobes were tested. The areas of the core and fan stream were held constant to maintain a bypass ratio of approximately 5. The research results presented in this report were obtained as part of a program directed toward developing an improved mixer design methodology by using a combined analytical and experimental approach. The effects of lobe spacing, lobe penetration, lobe-to-centerbody gap, lobe contour, and scalloping of the radial side walls were investigated. Test measurements included total pressure and temperature surveys, flow angularity surveys, and wall and centerbody surface static pressure measurements. Contour plots at various stations in the mixing region are presented to show the mixing effectiveness for the various lobe geometries.