Sample records for voltage stability evaluation

  1. Wind Power Plant Voltage Stability Evaluation: Preprint

    SciTech Connect

    Muljadi, E.; Zhang, Y. C.

    2014-09-01

    Voltage stability refers to the ability of a power system to maintain steady voltages at all buses in the system after being subjected to a disturbance from a given initial operating condition. Voltage stability depends on a power system's ability to maintain and/or restore equilibrium between load demand and supply. Instability that may result occurs in the form of a progressive fall or rise of voltages of some buses. Possible outcomes of voltage instability are the loss of load in an area or tripped transmission lines and other elements by their protective systems, which may lead to cascading outages. The loss of synchronism of some generators may result from these outages or from operating conditions that violate a synchronous generator's field current limit, or in the case of variable speed wind turbine generator, the current limits of power switches. This paper investigates the impact of wind power plants on power system voltage stability by using synchrophasor measurements.

  2. Voltage stability evaluation using modal analysis

    Microsoft Academic Search

    B. Gao; G. K. Morison; P. Kundur

    1992-01-01

    The authors discuss the voltage stability analysis of large power systems by using a modal analysis technique. The method computes, using a steady-state system model, a specified number of the smallest eigenvalues and the associated eigenvectors of a reduced Jacobian matrix. The eigenvalues, each of which is associated with a mode of voltage\\/reactive power variation, provide a relative measure of

  3. PMU Configuration Scheme of Regional Power System and Dynamic Voltage Stability Online Evaluation of Substation

    Microsoft Academic Search

    Dongxiao Niu; Zhuangzhi Liu; Honglei Yang

    2010-01-01

    By use of power system analysis software BPA, the power flow of a certain regional power network was simulated; From this the nodes and zones with weak voltage stability were found out , and an optimal configuration scheme of pharos measurement units(PMUs) in this regional power network was proposed. By means of indentifying equivalent impedances with recursive least square method,

  4. Two-position dc pulse voltage stabilizer

    NASA Technical Reports Server (NTRS)

    Osadchiy, V. I.

    1974-01-01

    The advantages of the dc pulse voltage stabilizers over the continuous action stabilizers are described. These advantages include higher efficiency, low sensitivity to the ambient temperature and insignificant size and weight. A comparison is made between the schematics of the known two position pulse stabilizer with a Schmitt trigger and that developed by the author. A characteristic feature of the improved system is the increased stabilization coefficient and the possibility of smooth regulation of the output voltage. A practical schematic is presented for the improved two position pulse stabilizer along with its parameters.

  5. Voltage stability in distribution networks with DG

    Microsoft Academic Search

    M. Alonso; H. Amaris

    2009-01-01

    This paper presents a methodology for optimal placement of DG units in power networks to guarantee the voltage profile, maximize loadability conditions in normal and in contingencies situations. The methodology aims in finding the configuration, among a set of system components, which meets the desired system reliability requirements taking into account stability limits. Results shown in the paper indicate that

  6. Voltage, Stability and Diffusion Barrier Differences between Sodium-ion and Lithium-ion Intercalation Materials

    E-print Network

    Ong, Shyue Ping

    To evaluate the potential of Na-ion batteries, we contrast in this work the difference between Na-ion and Li-ion based intercalation chemistries in terms of three key battery properties—voltage, phase stability and diffusion ...

  7. Application of artificial neural networks in voltage stability assessment

    SciTech Connect

    El-Keib, A.A.; Ma, X. [Univ. of Alabama, Tuscaloosa, AL (United States). Dept. of Electrical Engineering] [Univ. of Alabama, Tuscaloosa, AL (United States). Dept. of Electrical Engineering

    1995-11-01

    Voltage stability problems have been one of the major concerns for electric utilities as a result of system heavy loading. This paper reports on an investigation on the application of ANNs in voltage stability assessment. A multi-layer feed-forward artificial neural network (ANN) with error back-propagation learning is proposed for calculation of voltage stability margins (VSM). Based on the energy method, a direct mapping relation between system loading conditions and the VSMs is set up via the ANN. A systematic method for selecting the ANN`s input variables was developed using sensitivity analysis. The effects of ANN`s training pattern sensitivity problems were also studied by dividing system operating conditions into several loading levels based on sensitivity analysis. Extensive testing of the proposed ANN-based approach indicate its viability for power system voltage stability assessment. Simulation results on five test systems are reported in the paper.

  8. Optimal reactive power dispatch algorithm for voltage stability improvement

    Microsoft Academic Search

    Bansilal D. Thukaram; K. Parthasarathy

    1996-01-01

    This paper presents an algorithm for monitoring and improving voltage stability in power systems for a base case and credible contingency conditions. The monitoring methodology proposed here is based on the L-index of load buses. This index uses information on a normal load flow and is in the range of 0 (no load of system) to 1 (voltage collapse). The

  9. Use of local measurements to estimate voltage-stability margin

    Microsoft Academic Search

    Khoi Vu; Miroslav M. Begovic; Damir Novosel; Murari Mohan Saha

    1999-01-01

    Estimating the proximity of power systems to voltage collapse in real time still faces difficulties. Beside the data management and computational issues, any central control method is subject to the reliability of long-distance data communications. In the paper, the authors describe a new data processing method to estimate the proximity to voltage collapse. The method (code-named SMARTDevice, for Stability Monitoring

  10. Phasor measurement placement for voltage stability analysis of power systems

    Microsoft Academic Search

    L. Mili; T. Baldwin; R. Adapa

    1990-01-01

    The use of real-time phasor measurements for voltage stability analysis of power systems is considered. Two schemes of phasor measurement unit (PMU) placement have been investigated. In the first scheme, PMUs are used as pilot points for the secondary voltage control of a power system. Several criteria for pilot point selections are reviewed and assessed. In the second scheme, the

  11. STATCOM Modeling for Voltage and Angle Stability Studies

    Microsoft Academic Search

    Claudio A. Canizares; Massimo Pozzi; Sandro Corsi; Edvina Uzunovic

    2003-01-01

    This paper proposes and validates models to accurately represent STATic Syn- chronous Shunt COMpensators (STATCOM) in voltage and angle stability studies of powers systems. The proposed STATCOM stability models are justified based on the basic operational characteristics of this Flexible AC Transmission System (FACTS) controller for both phase and PWM control strategies. These models are first validated by means of

  12. STATCOM modeling for voltage and angle stability studies

    Microsoft Academic Search

    Claudio A. Cañizares; Massimo Pozzi; Sandro Corsi; Edvina Uzunovic

    2003-01-01

    This paper proposes and validates models to accurately represent static synchronous shunt compensators (STATCOM) in voltage and angle stability studies of powers systems. The proposed STATCOM stability models are justified based on the basic operational characteristics of this flexible AC transmission system (FACTS) controller for both phase and PWM control strategies. These models are first validated by means of EMTP

  13. High voltage stability performance of a gamma ray detection device

    NASA Astrophysics Data System (ADS)

    Abdullah, Nor Arymaswati; Lombigit, Lojius; Rahman, Nur Aira Abd

    2014-02-01

    An industrial grade digital radiation survey meter device is currently being developed at Malaysian Nuclear Agency. This device used a cylindrical type Geiger Mueller (GM) which acts as a detector. GM detector operates at relatively high direct current voltages depend on the type of GM tube. This thin/thick walled cylindrical type of GM tube operates at 450-650 volts range. Proper value and stability performance of high voltage are important parameters to ensure that this device give a reliable radiation dose measurement. This paper will present an assessment of the stability and performance of the high voltage supply for radiation detector. The assessment is performed using System Identification tools box in MATLAB and mathematical statistics.

  14. Planning Reconfigurable Reactive Control for Voltage Stability Limited Power Systems

    Microsoft Academic Search

    Haifeng Liu; Licheng Jin; James D. McCalley; Ratnesh Kumar; Venkataramana Ajjarapu; Nicola Elia

    2009-01-01

    This paper proposes an optimization-based method of planning reactive power control for electric transmission systems to endow them with the capability of being reconfigured to a secure configuration under a list of contingencies. The overall objective function is to minimize the installation cost of new controls such as mechanically switched capacitors, while satisfying the requirements of voltage stability margin and

  15. Impact of wind turbine systems on power system voltage stability

    Microsoft Academic Search

    D. Devaraj; R. Jeevajyothi

    2011-01-01

    This paper investigates the effect of fixed speed and variable speed grid-connected wind generators on the voltage stability of a power system network. The wind generators considered are the squirrel cage induction generator (SCIG), which is a fixed speed, the doubly-fed induction generator (DFIG) and the direct driven synchronous generator (DDSG) which are variable speed. Studies were conducted on a

  16. Contribution Allocation for Voltage Stability In Deregulated Power Systems

    E-print Network

    that the power factor of the load is constant as the load changes. We also assumed that the voltage dynamic, stability margin I. INTRODUCTION The deregulated power system is based on transactions; each part and one load bus system is used to demonstrate our approach. The system has three basic parts of the power

  17. A practical voltage-stability-constrained optimal power flow

    Microsoft Academic Search

    Rafael J. Avalos; Claudio A. Canizares; Miguel F. Anjos

    2008-01-01

    This paper proposes a novel and practical method to enforce a voltage stability constraint (VSC) in an optimal power flow (OPF) auction model, based on the minimum singular value and minimum singular vectors of the power flow Jacobian. The proposed technique is based on a singular value decomposition of the power flow Jacobian at a given solution point, plus an

  18. Concepts of undervoltage load shedding for voltage stability

    Microsoft Academic Search

    C. W. Taylor

    1992-01-01

    Undervoltage load shedding is an economical solution (or partial solution) to the voltage stability challenges facing electric utilities. Simulations, for an equivalent system and for large scale representation of the Puget Sound (Seattle) area of the Pacific Northwest, lead to several concepts for an undervoltage load shedding program. In this paper application factors such as undervoltage relay settings and time

  19. Transient stability enhancement and voltage regulation of power systems

    Microsoft Academic Search

    Youyi Wang; David J. Hill; Richard H. Middleton; Long Gao

    1993-01-01

    Improvement of the transient stability and voltage regulation of a single-machine-infinite-bus power system under the effects of a symmetrical three-phase short-circuit fault is detailed. The dynamical model of the system is described. A design strategy for nonlinear controllers is considered, and the design of a nonlinear variable-structure excitation controller is described. Simulation results obtained using the nonlinear excitation controller are

  20. Dynamic Voltage Stabilization of Stand-Alone Wind Energy Schemes

    Microsoft Academic Search

    A. M. Sharafe; A. S. Aljankawey; I. H. Altas

    2007-01-01

    Voltage stability is one of the serious problems in stand- alone wind energy schemes utilizing the induction generator especially under wind excursion and load variation. This paper presents a novel low cost Modulated Power Filter Compensator FACTS based-MPFC for a stand-alone green energy renewable wind energy conversion systems using self-excited low cost squirrel-cage induction generator (SEIG) driven by a wind

  1. Concepts of undervoltage load shedding for voltage stability

    SciTech Connect

    Taylor, C.W. (Bonneville Power Administration, Portland, OR (US))

    1992-04-01

    Undervoltage load shedding is an economical solution (or partial solution) to the voltage stability challenges facing electric utilities. Simulations, for an equivalent system and for large scale representation of the Puget Sound (Seattle) area of the Pacific Northwest, lead to several concepts for an undervoltage load shedding program. In this paper application factors such as undervoltage relay settings and time delay are discussed. Pacific Northwest utilities are implementing undervoltage load shedding for the 1991-1992 winter operating period.

  2. Modal Voltage Stability Analysis of Multi-infeed HVDC System Considering its Control Systems

    NASA Astrophysics Data System (ADS)

    Wu, Guohong; Minakawa, Tamotsu; Hayashi, Toshiyuki

    This work presents a method for investigating the voltage stability of multi-infeed HVDC systems, which is based on the eigenvalue decomposition technique known as modal analysis. In this method, the eigenvalue of linearized steady-state system power-voltage equations are computed to evaluate the long-term voltage stability. The contributions of this work to modal analysis method are control systems of HVDC system, such as an Automatic Power Regulator (APR) and an Automatic (DC) Current Regulator (ACR) on its rectifier side and a changeover between an Automatic (DC) Voltage Regulator (AVR) and an Automatic extinction advance angle Regulator (A?R) modes on its inverter side, were taken into account, and the formularization for modal analysis considering not only these control systems of HVDC system but also generator and load characteristics was fulfilled and presented in this paper. The application results from an AC/DC model power system with dual HVDC systems verified the efficiency of the proposed method and quantitatively illustrated the influence of control systems of HVDC system on AC/DC system long-term voltage stability.

  3. Security constrained coordinated dynamic voltage stabilization based on model predictive control

    Microsoft Academic Search

    Licheng Jin; Ratnesh Kumar

    2009-01-01

    Voltage instability and voltage collapse are complicated phenomenon which can be influenced by the interactions of all power system components. This paper presents an approach for optimal coordination of static Var compensators (SVCs), transformer under load tap changers (ULTCs) and load shedding to improve voltage performance following disturbances and also to ensure a desired amount of post-transient voltage stability margin

  4. Voltage-stability protection and control using a wide-area network of phasor measurements

    Microsoft Academic Search

    B. Milosevic; M. Begovic

    2003-01-01

    This paper presents a concept for local monitoring of the onset of voltage collapse, protective, and emergency control in the presence of voltage-sensitive loads. The onset of voltage collapse point is calculated based on the load characteristics and simulated voltage and current phasors measurements, which are provided by a network of phasor-measurement units. If the stability margin is small and

  5. Comparing secondary voltage regulation and shunt compensation for improving voltage stability and transfer capability in the Italian power system

    Microsoft Academic Search

    Claudio A. Cañizares; Claudio Cavallo; Massimo Pozzi; Sandro Corsi

    2005-01-01

    This paper concentrates on comparing the advantages and disadvantages, including costs, of using secondary voltage regulation (SVR) versus using shunt-connected controllers, in particular mechanical switched capacitors (MSC), static var compensators (SVC) and static synchronous compensators (STATCOM), to improve voltage stability (VS) and the external transfer capability (TC) of the Italian power network. Basic VS and TC concepts and tools, as

  6. Power flow and transient stability models of FACTS controllers for voltage and angle stability studies

    Microsoft Academic Search

    C. A. Canizares

    2000-01-01

    This paper presents transient stability and power flow models of thyristor controlled reactor (TCR) and voltage sourced inverter (VSI) based flexible AC transmission system (FACTS) controllers. Models of the static VAr compensator (SVC), the thyristor controlled series compensator (TCSC), the static VAr compensator (STATCOM), the static synchronous source series compensator (SSSC), and the unified power flow controller (UPFC) appropriate for

  7. Ultrasonic evaluation of high voltage circuit boards

    NASA Technical Reports Server (NTRS)

    Klima, S. J.; Riley, T. J.

    1976-01-01

    Preliminary observations indicate that an ultrasonic scanning technique may be useful as a quick, low cost, nondestructive method for judging the quality of circuit board materials for high voltage applications. Corona inception voltage tests were conducted on fiberglass-epoxy and fiberglass-polyimide high pressure laminates from 20 to 140 C. The same materials were scanned ultrasonically by utilizing the single transducer, through-transmission technique with reflector plate, and recording variations in ultrasonic energy transmitted through the board thickness. A direct relationship was observed between ultrasonic transmission level and corona inception voltage. The ultrasonic technique was subsequently used to aid selection of high quality circuit boards for the Communications Technology Satellite.

  8. Preventive and corrective open access system dispatch based on the voltage stability security assessment and diagnosis

    Microsoft Academic Search

    R. A. Schlueter; S. Liu; N. Alemadi

    2001-01-01

    The capabilities of the voltage stability security assessment (VSSAD) to assess proximity to and ranking voltage instability by (a) performing a contingency selection of each model determined subsystem and (b) diagnosing where, why, when and what can be done to cure voltage instability for each equipment outage and transaction combination is thoroughly documented in IEEE Trans. Power Syst. 13 (1998)

  9. Measurement based Voltage Stability Monitoring of Power system Garng M. Huang

    E-print Network

    factors for the voltage stability problem, etc. II. FUNDAMENTALS: SIGLE GENERATOR AND LOAD SYSTEM #12;A to find the most vulnerable area in a system, to find the impacts of other loads, areas and power, Transient Analysis I. INTRODUCTION Voltage stability is a major concern in planning and operations of power

  10. A New Optimal Routing Algorithm for Loss Minimization and Voltage Stability Improvement in Radial Power Systems

    Microsoft Academic Search

    Joong-Rin Shin; Byung-Seop Kim; Jong-Bae Park; Kwang Y. Lee

    2007-01-01

    This paper presents an optimal routing algorithm (ORA) for minimizing power loss and at the same time maximizing the voltage stability in radial power systems. In the proposed ORA, a voltage stability index (VSI) for real-time assessment is introduced based on the conventional critical transmission path framework. In addition, the algorithm can automatically detect the critical transmission paths that will

  11. Voltage Stability and Frequency Synchronization of Weak Power Distribution Networks with Inverter-Based

    E-print Network

    Lemmon, Michael

    Voltage Stability and Frequency Synchronization of Weak Power Distribution Networks with Inverter not apply to truly weak networks. Key words: Weak networks, inverter-based distributed generator, voltage and frequency stability. 1 INTRODUCTION Inverter-based distributed generation (DG) sources are usually a part

  12. Monitoring and control of voltage stability in power systems

    SciTech Connect

    Sallam, A.A.; Aboul-Ela, M.E.; Elaraby, E.E. [Suez Canal Univ., Port-Said (Egypt)

    1995-12-31

    This paper proposes a new technique in controlling voltage instability in power systems. This technique coordinates between the reactive power of excitation systems and that of static var compensators (SVCs). The method starts with the decomposition of system into several voltage control areas (VCAs). When a reactive power deficiency occurs in certain area, excitation systems respond first to supply the required reactive power by increasing reactive generation of synchronous generators to its upper limit. If more reactive power is needed within the specific area to recover voltage instability, a SVC will be inserted by a switching controller in order to achieve the reactive balance. This controller receives an actuating signal when the terminal voltage is still unsatisfactory. By this technique, it is possible to fully utilize the excitation systems reactive power, and to design economic size SVCs to recover voltage instability. The application of the proposed technique on the New-England 39 bus system proves its efficiency in controlling voltage instability.

  13. Coordinated dynamic voltage stabilization based on model predictive control

    Microsoft Academic Search

    Licheng Jin; Ratnesh Kumar

    2009-01-01

    Keeping voltages of all buses within acceptable bounds is very important for power system operations. This paper presents an approach for optimal coordination of static var compensators (SVCs), transformer under load tap changers (ULTCs) and load shedding to improve voltage performance following large disturbances. The approach is based on model predictive control (MPC) with a decreasing control horizon. The MPC

  14. Shrinking stability regions and voltage collapse in power systems

    Microsoft Academic Search

    Khoi T. Vu; Chen-Ching Liu

    1992-01-01

    The dynamic process of voltage collapse is analyzed based on three mechanisms: on-load tap-changing, load dynamics, and generator excitation limiting. The interaction among these mechanisms and how the voltage collapse takes place are thoroughly investigated in a general interconnected network model under the assumption that system frequency remains unchanged. It is found that, so long as an equilibrium exists, there

  15. Design of EBW Stabilized High-Voltage Source Based on Fuzzy PID Control

    Microsoft Academic Search

    He Shaojia; Mo Jinhai; Wei Shouqi; Huang Dao

    2007-01-01

    A novel PWM-BOOST type EBW (electron beam welder) stabilized high-voltage source circuit system is introduced. This system consists of setting-up transformer, PWM-BOOST converter and a current limiter. PWM-BOOST converter can step up the voltage with the ratio higher than 1:5.5; as a result, the transformer's output voltage is decreased and its structure can be simplified. Due to the strongly non-linearity

  16. A multivariable new control solution for increased long lines voltage restoration stability during black startup

    Microsoft Academic Search

    Sandro Corsi; Massimo Pozzi

    2003-01-01

    This paper deals with the stability problems which can determine failures of long lines voltage restoration maneuvers during black startup. Also of concern, a new control solution is shown, capable of facing the phenomena of voltage instability and self-excitation, which frequently occur in the alternator-line system. The paper presents a theoretical analysis, which reconstructs and justifies the described dynamic phenomena.

  17. Design of a Novel PWM Boost Type EBW Stabilized High Voltage Source

    Microsoft Academic Search

    Shaojia He; Jinhai Mo; Shouqi Wei; Dao Huang

    2007-01-01

    The designing of a novel circuit system of electron beam welder stabilized high-voltage supply is presented in this paper. Its main circuit is based on PWM Boost converter topology. A switch current limiter (SCL) is used to suppress the surge current and a practical PID controller is designed to regulate the output voltage. The Saber simulation results show that the

  18. A Novel Voltage Stabilization Control Scheme for Stand-alone Wind Energy Conversion Systems

    Microsoft Academic Search

    A. M. Sharaf; A. Aljankawey; I. H. Altas

    2007-01-01

    This paper proposes a novel low cost FACTS based voltage stabilization scheme for a stand-alone wind energy conversion systems using self excited squirrel-cage induction generator (SEIG) driven by a wind turbine and interfaced to electric load. The new control scheme is designed not only to ensure bus voltage stabilization, but also to improve energy utilization using a low-cost PWM-switched modulated

  19. A new application area for fullerenes: voltage stabilizers for power cable insulation.

    PubMed

    Jarvid, Markus; Johansson, Anette; Kroon, Renee; Bjuggren, Jonas M; Wutzel, Harald; Englund, Villgot; Gubanski, Stanislaw; Andersson, Mats R; Müller, Christian

    2015-02-01

    Fullerenes are shown to be efficient voltage-stabilizers for polyethylene, i.e., additives that increase the dielectric strength of the insulation material. Such compounds are highly sought-after because their use in power-cable insulation may considerably enhance the transmission efficiency of tomorrow's power grids. On a molal basis, fullerenes are the most efficient voltage stabilizers reported to date. PMID:25504254

  20. Voltage stability constrained OPF market models considering N ? 1 contingency criteria

    Microsoft Academic Search

    Federico Milano; Claudio A. Cañizares; Marco Invernizzi

    2005-01-01

    This paper proposes two novel techniques for including contingencies in OPF-based electricity market computations and for the estimation of a “system-wide” available transfer capability (SATC). The OPF problem formulation includes voltage stability constraints and a loading parameter in order to ensure a proper stability margin for the market solution. Two methods are proposed. The first technique is an iterative approach

  1. Long term voltage stability analysis for small disturbances 

    E-print Network

    Men, Kun

    2009-05-15

    LIST OF FIGURES...............................................................................................................ix LIST OF TABLES... ................................................................................................................... 113 VITA................................................................................................................................... 117 ix LIST OF FIGURES Page Figure II-1 Dynamic vs. static stability margin...

  2. Influence of dump voltage and allowable temperature rise on stabilizer requirements in superconducting coils

    SciTech Connect

    Schwenterly, S.W.

    1988-01-01

    A superconducting winding must have enough stabilizer to satisfy two sets of criteria. During normal operation, the amount of stabilizer must be large enough either to make the coil unconditionally stable or to give a certain desired stability margin. Once a dump occurs, the amount of stabilizer must be large enough to carry the current without generating excessive dump voltages or allowing the winding to exceed a certain maximum temperature (and maximum pressure, in the case of force-cooled coils). The voltage criterion often dominates for very large coil systems, but it is frequently ignored in initial design studies. This paper gives some simple relations between the dump voltage and the stored energy, temperature rise, and coil geometry that are useful in scooping the required amount of stabilizer. Comparison with some recently proposed fusion magnet system designs indicates that excessive dump voltages could result in some cases. High-temperature superconductors may require more stabilizer than the conventional alloys. Calculations with simple model coil systems indicate how trade-offs between various coil parameters affect the dump voltage. 12 refs., 1 fig., 1 tab.

  3. Biological sludge stabilization reactor evaluations

    SciTech Connect

    Corbitt, R.A.; Bowen, P.T.; Smith, P.E.

    1998-07-01

    Anaerobic digestion was chosen as the means to stabilize primary and thickened waste activated sludge for a 0.88 m{sup 3}/s (20 mgd) advanced wastewater reclamation facility. Two stage digestion was proposed to produce Class B sludge. Reactor shape was an important variable in design of the first stage digestion. Evaluation of conventional and egg shaped anaerobic digesters was performed. Based on the economic and non-economic criteria analysis, egg shaped reactors were selected.

  4. Evaluation of higher distribution and/or utilization voltages. Fifth interim report (September 1980): assess constraints to higher voltage implementation

    SciTech Connect

    Not Available

    1981-04-01

    This interim report provides documentation on the fifth task, Assess Constraints to Higher Voltage Implementation, of DOE Contract No. ET-78-C-01-2866, Evaluation of Higher Distribution and/or Utilization Voltages. The work performed under this task includes the development of a list of impediments to higher voltage implementation including both technological and economic factors, an assessment of the impact of reduced costs for high voltage equipment on the selection of an optimal voltage and a set of recommendations for further work.

  5. Self-organized synchronization and voltage stability in networks of synchronous machines

    NASA Astrophysics Data System (ADS)

    Schmietendorf, Katrin; Peinke, Joachim; Friedrich, Rudolf; Kamps, Oliver

    2014-10-01

    The integration of renewable energy sources in the course of the energy transition is accompanied by grid decentralization and fluctuating power feed-in characteristics. This development raises novel challenges for power system stability and design. We investigate power system stability from the viewpoint of self-organized synchronization aspects. In this approach, the power grid is represented by a network of synchronous machines. We supplement the classical Kuramoto-like network model, which assumes constant voltages, with dynamical voltage equations, and thus obtain an extended model, that incorporates the coupled categories voltage stability and rotor angle synchronization. We compare disturbance scenarios in small systems simulated on the basis of both classical and extended model and we discuss resultant implications and possible applications to complex modern power grids.

  6. Transient Stability using Energy Function Method in Power Systems Close to Voltage Collapse

    Microsoft Academic Search

    Manfred F. Bedriñana; V. Leonardo Paucar; Carlos A. Castro

    2007-01-01

    In this paper, the direct methods performance, based in energy functions, are analyzed for transient stability of power systems close to voltage collapse. These cases were simulated, increasing the loading close to maximum loading point (MLP) values. According the obtained results, in potential energy boundary surface (PEBS) method, unstable equilibrium point (UEP) were computed and the interaction resultant was shown

  7. A novel fuzzy index for steady state voltage stability analysis and identification of critical busbars

    Microsoft Academic Search

    P. K. Satpathy; D. Das; P. B. Dutta Gupta

    2002-01-01

    In this paper, a novel fuzzy index is proposed for the prediction of steady state voltage stability conditions in transmission networks. The uncertainties in the input parameters are efficiently modeled in terms of fuzzy sets by assigning trapezoidal and triangular membership functions. The results include fuzzy load flow solutions for the base case and critical conditions with and without contingencies.

  8. An improved direct feedback linearization technique for transient stability enhancement and voltage regulation of power generators

    Microsoft Academic Search

    Godpromesse Kenné; Raphaël Goma; Homère Nkwawo; Françoise Lamnabhi-Lagarrigue; Amir Arzandé; Jean Claude Vannier

    2010-01-01

    In this paper, a simple improved direct feedback linearization design method for transient stability and voltage regulation of power systems is discussed. Starting with the classical direct feedback linearization technique currently applied to power systems, an adaptive nonlinear excitation control of synchronous generators is proposed, which is new and effective for engineering. The power angle and mechanical power input are

  9. Flexible low-voltage organic transistors with high thermal stability at 250 °C.

    PubMed

    Yokota, Tomoyuki; Kuribara, Kazunori; Tokuhara, Takeyoshi; Zschieschang, Ute; Klauk, Hagen; Takimiya, Kazuo; Sadamitsu, Yuji; Hamada, Masahiro; Sekitani, Tsuyoshi; Someya, Takao

    2013-07-19

    Low-operating-voltage flexible organic thin-film transistors with high thermal stability using DPh-DNTT and SAM gate dielectrics are reported. The mobility of the transistors are decreased by 23% after heating to 250 °C for 30 min. Furthermore, flexible organic pseudo-CMOS inverter circuits, which are functional after heating to 200 °C, are demonstrated. PMID:23616376

  10. Voltage stability consequences of decentralized generation and possibilities for intelligent control

    Microsoft Academic Search

    Freek Baalbergen; Madeleine Gibescu; Lou van der Sluis

    2010-01-01

    Many decentralized generation technologies are mature today. For the Dutch power system it is expected that in 2020 Decentralized Generators (DGs) form a major (about 35 %) part of the total production capacity. This expectation is true all over the world. A large share of DG will influence the voltage stability of the system. The objective of this paper is

  11. Voltage Stability Analysis With Optimum Size and Location Based Synchronous Machine DG

    E-print Network

    Pota, Himanshu Roy

    Voltage Stability Analysis With Optimum Size and Location Based Synchronous Machine DG Adnan Anwar feeder has been considered to determine the optimum size and location of a synchronous machine based DG.pota@adfa.edu.au. At present, most distributed generation installations employ induction and synchronous machines [7]. Before

  12. WSCC voltage stability criteria, undervoltage load shedding strategy, and reactive power reserve monitoring methodology

    Microsoft Academic Search

    Abbas M. Abed

    1999-01-01

    Engineers have long been struggling with developing voltage stability criteria for their systems. The development of the criteria becomes even more difficult if one attempts to apply the criteria to an entire region such as the one within Western Systems Coordinating Council (WSCC). The WSCC which is comprised of 86 member systems from the western region of North America (Canada,

  13. Basis for allosteric open-state stabilization of voltage-gated potassium channels by intracellular cations.

    PubMed

    Goodchild, Samuel J; Xu, Hongjian; Es-Salah-Lamoureux, Zeineb; Ahern, Christopher A; Fedida, David

    2012-11-01

    The open state of voltage-gated potassium (Kv) channels is associated with an increased stability relative to the pre-open closed states and is reflected by a slowing of OFF gating currents after channel opening. The basis for this stabilization is usually assigned to intrinsic structural features of the open pore. We have studied the gating currents of Kv1.2 channels and found that the stabilization of the open state is instead conferred largely by the presence of cations occupying the inner cavity of the channel. Large impermeant intracellular cations such as N-methyl-d-glucamine (NMG(+)) and tetraethylammonium cause severe slowing of channel closure and gating currents, whereas the smaller cation, Cs(+), displays a more moderate effect on voltage sensor return. A nonconducting mutant also displays significant open state stabilization in the presence of intracellular K(+), suggesting that K(+) ions in the intracellular cavity also slow pore closure. A mutation in the S6 segment used previously to enlarge the inner cavity (Kv1.2-I402C) relieves the slowing of OFF gating currents in the presence of the large NMG(+) ion, suggesting that the interaction site for stabilizing ions resides within the inner cavity and creates an energetic barrier to pore closure. The physiological significance of ionic occupation of the inner cavity is underscored by the threefold slowing of ionic current deactivation in the wild-type channel compared with Kv1.2-I402C. The data suggest that internal ions, including physiological concentrations of K(+), allosterically regulate the deactivation kinetics of the Kv1.2 channel by impairing pore closure and limiting the return of voltage sensors. This may represent a primary mechanism by which Kv channel deactivation kinetics is linked to ion permeation and reveals a novel role for channel inner cavity residues to indirectly regulate voltage sensor dynamics. PMID:23071269

  14. Evaluation of fast voltage discriminators in the picosecond time range

    SciTech Connect

    Kolbe, W.F.; Turko, B.; Smith, C.

    1989-02-01

    An automated system for the evaluation of fast risetime voltage discriminators is described. A high-performance time digitizer is used to determine the elapsed time between the generation of a test pulse and the response of the discriminator under test. The measurement is repeated for a series of discriminator threshold levels generated by a digital-to-analog converter and the results compared to a photograph of the leading edge of the pulse obtained with a sampling socilloscope. To obtain high accuracy, an average of several thousand individual digitizations is used in each measurement to reduce the uncertainty to a maximum of +-3 ps. The measurement system is used with a test fixture to evaluate the performance of a number of tunnel diodes and in preliminary measurements of a prototype discriminator of new design.

  15. Evaluation of fast voltage discriminators in the picosecond time range

    SciTech Connect

    Kolbe, W.F.; Turko, B.T.; Smith, R.C.

    1988-04-01

    An automated system for the evaluation of fast risetime voltage discriminators is described. A high-performance time digitizer is used to determine the elapsed time between the generation of a test pulse and the response of the discriminator under test. The measurement is repeated for a series of discriminator threshold levels generated by a digital-to-analog converter and the results compared to a photograph of the leading edge of the pulse obtained with a sampling oscilloscope. To obtain high accuracy, an average of several thousand individual digitizations is used in each measurement to reduce the uncertainty to a maximum of +-3 ps. The measurement system is used with a test fixture to evaluate the performance of a number of tunnel diodes and in preliminary measurements of a prototype discriminator of new design. 2 refs., 9 figs.

  16. Chemical detection and laser wavelength stabilization employing spectroscopic absorption via laser compliance voltage sensing

    DOEpatents

    Taubman, Matthew S; Phillips, Mark C

    2014-03-18

    Systems and methods are disclosed that provide a direct indication of the presence and concentration of an analyte within the external cavity of a laser device that employ the compliance voltage across the laser device. The systems can provide stabilization of the laser wavelength. The systems and methods can obviate the need for an external optical detector, an external gas cell, or other sensing region and reduce the complexity and size of the sensing configuration.

  17. Lyapunov-Popov stability analysis of synchronous machine with flux decay and voltage regulator

    Microsoft Academic Search

    M. A. PAI; VISHWANATHA RAI

    1974-01-01

    The transient stability of ft synchronous machine connected to an infinite bus ia studied, including the flux decay effect, and voltage regulator action, through Lyapunov-Popov approach. This problem belongs to the general class of systems having multi-argument non-linearities. A systematic procedure to construct a Lyapunov function is evolved by combining a criterion of Dosoer and Wn (1909) and Kalman's construction

  18. Voltage stability of the Puget Sound system under abnormally cold weather conditions

    SciTech Connect

    Jimma, K.M.; Sheehan, M.T. (Puget Sound Power and Light, Bellevue, WA (United States)); Comegys, G.L. (Bonneville Power Administration, Portland, OR (United States)); Miller, N.W.; D'Aquila, R.

    1993-08-01

    The potential for voltage collapse in the Puget Sound area is analyzed. Shunt and series compensation schemes, as well as undervoltage load shedding, are evaluated. Twenty-five minute time simulations of the Puget Sound area system are presented, showing interaction of load dynamics with LTCs, switched compensation and protective equipment. Results and analysis are relevant to utilities worldwide which must address similar concerns.

  19. Multi-objective Optimal Power Flows to Evaluate Voltage Security Costs in Power Networks

    E-print Network

    Cañizares, Claudio A.

    1 Multi-objective Optimal Power Flows to Evaluate Voltage Security Costs in Power Networks William-objective methodologies to op- timize active and reactive power dispatch while maximizing volt- age security in power to suggest possible ways of costing voltage security in power systems. Index Terms-- Voltage collapse

  20. A very low offset voltage auto-zero stabilized CMOS operational amplifier Daniel DZAHINI (1), Hamid Ghazlane (2)

    E-print Network

    Paris-Sud XI, Université de

    A very low offset voltage auto-zero stabilized CMOS operational amplifier Daniel DZAHINI (1), Hamid Abstract: A high precision operational amplifier has been developed in a standard .8µ CMOS process less than 2µV -100nV/°C. The amplifier with its output buffer consumes 5mW at a supply voltage of +/- 2

  1. Bi-stability, hysteresis, and memory of voltage-gated lysenin channels.

    PubMed

    Fologea, Daniel; Krueger, Eric; Mazur, Yuriy I; Stith, Christine; Okuyama, Yui; Henry, Ralph; Salamo, Greg J

    2011-12-01

    Lysenin, a 297 amino acid pore-forming protein extracted from the coelomic fluid of the earthworm E. foetida, inserts constitutively open large conductance channels in natural and artificial lipid membranes containing sphingomyelin. The inserted channels show voltage regulation and slowly close at positive applied voltages. We report on the consequences of slow voltage-induced gating of lysenin channels inserted into a planar Bilayer Lipid Membrane (BLM), and demonstrate that these pore-forming proteins constitute memory elements that manifest gating bi-stability in response to variable external voltages. The hysteresis in macroscopic currents dynamically changes when the time scale of the voltage variation is smaller or comparable to the characteristic conformational equilibration time, and unexpectedly persists for extremely slow-changing external voltage stimuli. The assay performed on a single lysenin channel reveals that hysteresis is a fundamental feature of the individual channel unit and an intrinsic component of the gating mechanism. The investigation conducted at different temperatures reveals a thermally stable reopening process, suggesting that major changes in the energy landscape and kinetics diagram accompany the conformational transitions of the channels. Our work offers new insights on the dynamics of pore-forming proteins and provides an understanding of how channel proteins may form an immediate record of the molecular history which then determines their future response to various stimuli. Such new functionalities may uncover a link between molecular events and macroscopic processing and transmission of information in cells, and may lead to applications such as high density biologically-compatible memories and learning networks. PMID:21945404

  2. Leakage current and stability of acrylic elastomer subjected to high DC voltage

    NASA Astrophysics Data System (ADS)

    Hammami, S.; Jean-Mistral, C.; Jomni, F.; Gallot-Lavallée, O.; Rain, P.; Yangui, B.; Sylvestre, A.

    2015-04-01

    Dielectric elastomers such as 3M VHB4910 acrylate film have been widely used for electromechanical energy conversion such as actuators, sensors and generators, due to their lightweight, high efficiency, low cost and high energy density. Mechanical and electric properties of such materials have been deeply investigated according to various parameters (temperature, frequency, pre-stress, nature of the compliant electrodes…). Models integrating analytic laws deduced from experiments increase their accuracy. Nevertheless, leakage current and electrical breakdown reduce the efficiency and the lifetime of devices made with these polymers. These two major phenomena are not deeply investigated in the literature. Thus, this paper describes the current-voltage characteristics of acrylate 3M VHB4910 and investigates the stability of the current under high electric field (kV) for various temperatures (from 20°C to 80°C) and over short (300 s) and long (12h) periods. Experimental results show that, with gold electrodes at ambient temperature, the current decreases with time to a stable value corresponding to the conduction current. This decrease occurs during 6 hours, whereas in the literature values of current at short time (less than 1 hour) are generally reported. This decrease can be explained by relaxations mechanisms in the polymer. Schottky emission and Poole-Frenkel emission are both evaluated to explain the leakage current. It emerges from this study that the Schottky effect constitutes the main mechanism of electric current in the 3M VHB4910. For high temperatures, the steady state is reached quickly. To end, first results on the leakage current changes for pre-stretch VHB4910 complete this study.

  3. Effects of high voltage electrical stimulation on the rate of pH decline, meat quality and color stability in chilled beef carcasses

    PubMed Central

    Mombeni, Ehsan Gharib; Mombeini, Manoochehr Gharib; Figueiredo, Lucas Chaves; Siqueira, Luciano Soares Jacintho; Dias, Debora Testoni

    2013-01-01

    Objective To determine the effects of high voltage electrical stimulation (HVES, 800 Voltage) on rapid decreases in pH values and improvements in meat quality. Methods A total of 50 beef carcasses were applied, divided into two groups, one as a control and another for HVES. Meat quality was evaluated based on M. longissimus dorsi by examining pH and temperature levels at 1, 2, 5, 10 and 24 h, while color stability was examined seven days after slaughter. Results HVES decreased the pH values of the meat and accelerated rigor mortis (P<0.05). HVES caused differences in instrumental color values compared with the control groups across the ageing period at 4 °C. Conclusion the HVES had positive effects on meat quality and color stability, in contrast to undesirable consumer preferences. PMID:23998012

  4. Stabilization of the Conductive Conformation of a Voltage-gated K+ (Kv) Channel

    PubMed Central

    Santos, Jose S.; Syeda, Ruhma; Montal, Mauricio

    2013-01-01

    Voltage-gated K+ (Kv) channels are molecular switches that sense membrane potential and in response open to allow K+ ions to diffuse out of the cell. In these proteins, sensor and pore belong to two distinct structural modules. We previously showed that the pore module alone is a robust yet dynamic structural unit in lipid membranes and that it senses potential and gates open to conduct K+ with unchanged fidelity. The implication is that the voltage sensitivity of K+ channels is not solely encoded in the sensor. Given that the coupling between sensor and pore remains elusive, we asked whether it is then possible to convert a pore module characterized by brief openings into a conductor with a prolonged lifetime in the open state. The strategy involves selected probes targeted to the filter gate of the channel aiming to modulate the probability of the channel being open assayed by single channel recordings from the sensorless pore module reconstituted in lipid bilayers. Here we show that the premature closing of the pore is bypassed by association of the filter gate with two novel open conformation stabilizers: an antidepressant and a peptide toxin known to act selectively on Kv channels. Such stabilization of the conductive conformation of the channel is faithfully mimicked by the covalent attachment of fluorescein at a cysteine residue selectively introduced near the filter gate. This modulation prolongs the occupancy of permeant ions at the gate. It is this longer embrace between ion and gate that we conjecture underlies the observed stabilization of the conductive conformation. This study provides a new way of thinking about gating. PMID:23609443

  5. Power system voltage stability and agent based distribution automation in smart grid

    NASA Astrophysics Data System (ADS)

    Nguyen, Cuong Phuc

    2011-12-01

    Our interconnected electric power system is presently facing many challenges that it was not originally designed and engineered to handle. The increased inter-area power transfers, aging infrastructure, and old technologies, have caused many problems including voltage instability, widespread blackouts, slow control response, among others. These problems have created an urgent need to transform the present electric power system to a highly stable, reliable, efficient, and self-healing electric power system of the future, which has been termed "smart grid". This dissertation begins with an investigation of voltage stability in bulk transmission networks. A new continuation power flow tool for studying the impacts of generator merit order based dispatch on inter-area transfer capability and static voltage stability is presented. The load demands are represented by lumped load models on the transmission system. While this representation is acceptable in traditional power system analysis, it may not be valid in the future smart grid where the distribution system will be integrated with intelligent and quick control capabilities to mitigate voltage problems before they propagate into the entire system. Therefore, before analyzing the operation of the whole smart grid, it is important to understand the distribution system first. The second part of this dissertation presents a new platform for studying and testing emerging technologies in advanced Distribution Automation (DA) within smart grids. Due to the key benefits over the traditional centralized approach, namely flexible deployment, scalability, and avoidance of single-point-of-failure, a new distributed approach is employed to design and develop all elements of the platform. A multi-agent system (MAS), which has the three key characteristics of autonomy, local view, and decentralization, is selected to implement the advanced DA functions. The intelligent agents utilize a communication network for cooperation and negotiation. Communication latency is modeled using a user-defined probability density function. Failure-tolerant communication strategies are developed for agent communications. Major elements of advanced DA are developed in a completely distributed way and successfully tested for several IEEE standard systems, including: Fault Detection, Location, Isolation, and Service Restoration (FLISR); Coordination of Distributed Energy Storage Systems (DES); Distributed Power Flow (DPF); Volt-VAR Control (VVC); and Loss Reduction (LR).

  6. Evaluation of a high power ARCP voltage source inverter with IGCTs

    Microsoft Academic Search

    S. Bernet; R. Teichmann; J. Weber; P. K. Steimer

    1999-01-01

    An evaluation and comparison of a two-level conventional voltage source inverter (VSI) and an auxiliary resonant commutated pole voltage source inverter (ARCPVSI) featuring IGCTs for a 3 MVA application is presented. Design issues of both topologies are addressed. The IGCT loss approximations are based on extensive measurements of the devices under hard and soft switching conditions. The results show that

  7. The study of countrate stability of photomultiplier tube with different types of voltage dividers

    SciTech Connect

    Yoshizawa, Y.; Yamaguchi, H.; Ooishi, N.; Suzuki, H.; Suzuki, S. [Hamamatsu Photonics K.K., Toyooka, Shizuoka (Japan). Electron Tube Center] [Hamamatsu Photonics K.K., Toyooka, Shizuoka (Japan). Electron Tube Center

    1996-06-01

    In the recent experiments for high energy physics (HEP), luminosity of beams has been increased to achieve the precise measurement. This leads to high countrate environment for photodetectors like photomultiplier tubes (PMTs). Even under such a condition, PMTs are required to be operated stably. To do that, it`s important to choose a suitable divider from several kinds of high voltage divider circuits. Countrate stability of PMTs was studied with different types of dividers, which were resistor base, booster base, transistor base (Tr. base) and Cockcroft-Walton base (CW base), to understand the effect of dividers. Booster base and Tr. base as well as CW base showed no gain deviation up to the average output current of 100 {micro} A. On the contrary, resistor base showed gain increase of 30% at the same condition. It was confirmed that booster base, Tr. base and CW base could be suitable dividers for high countrate environment.

  8. HIGH VOLTAGE ENVIRONMENTAL APPLICATIONS, INC.ELECTRON BEAM TECHNOLOGY - INNOVATIVE TECHNOLOGY EVALUATION REPORT

    EPA Science Inventory

    This report evaluates a high-voltage electron beam (E-beam) technology's ability to destroy volatile organic compounds (VOCs) and other contaminants present in liquid wastes. Specifically, this report discusses performance and economic data from a Superfund Innovative Technology...

  9. Evaluation of Conservation Voltage Reduction (CVR) on a National Level

    SciTech Connect

    Schneider, Kevin P.; Fuller, Jason C.; Tuffner, Francis K.; Singh, Ruchi

    2010-09-29

    Conservation Voltage Reduction (CVR) is a reduction of energy consumption resulting from a reduction of feeder voltage. While there have been numerous CVR systems deployed in North America there has been little substantive analytic analysis of the effect; the majority of the published results are based on empirical field measurements. Since these results are based on empirical measurements it is difficult to extrapolate how this technology will behave on the various types of distribution feeders found throughout the nation. This report has utilized the Taxonomy of Prototypical feeder developed under the Modern Grid Initiative (MGI), now the Modern Grid Strategy (MGS), in order to estimate the benefits of CVR on multiple distribution feeder types. This information will then be used to determine an estimate of the national benefits of a wide scale deployment of CVR.

  10. Evaluation of developing inertial stabilization unit

    NASA Astrophysics Data System (ADS)

    Haruna, Masaki; Kodeki, Kazuhide; Shimizu, Seiichi; Fukushima, Kazuhiko; Takahara, Osamu; Ando, Toshiyuki; Suzuki, Jiro; Haraguchi, Eisuke

    2015-03-01

    Micro vibrations generated from some internal disturbance sources such as a reaction wheel degrades the pointing stability of an observation satellite. To suppress the pointing error, we have been developing an inertial stabilization unit. A prototype mechanism is designed based on concepts that it has non-contact actuators and sensors, and rotational leaf springs are applied to support a stabilized platform in order to meet two requirements which are precise drive and tolerance for launch load. Two kind of inertial sensors are installed on the platform to measure the attitude directly. Each of these two inertial sensors covers low or high bandwidth signal respectively. These signals will be able to be combined as one wideband signal to stabilize the platform in inertial space. In this paper, the developing prototype mechanism and control equipment are described and the basic evaluation results are reported. Less than 0.3urad as a drive precision and more than 100Hz as a local sensor control bandwidth are verified. The development of the system has not completely finished yet, but the basic performance is certified to meet the design specification. From now on, we continue to develop the unit. These future results can be applied to inter-satellite laser communication system.

  11. Security constrained emergency voltage stabilization: A Model Predictive Control based approach

    Microsoft Academic Search

    Licheng Jin; Ratnesh Kumar; Nicola Elia

    2008-01-01

    Voltage instability impacts power system transfer limits and its reliability. This paper presents an approach to determine a voltage control scheme based on the model predictive control (MPC) theory. MPC is used to develop an optimal control strategy, consisting of a sequence of amounts of the shunt capacitors to switch. The resulting control strategy prevents voltage instability and maintains a

  12. Evaluation of Electrophoretic Migration by Optical and Current Responses to Cyclic-Polarity-Reversed Triangular Voltage

    NASA Astrophysics Data System (ADS)

    Sugita, Tatsuya; Ohshima, Tetsuya

    2011-12-01

    We studied the electrophoretic migration of electrophoretic inks by measuring the total reflection at the interface between the electrode and the ink solvent simultaneous with the current response to a cyclic-polarity-reversed triangular voltage. We demonstrated that the current peaks and optical responses to the cyclic-polarity-reversed triangular voltage are effective for the easy evaluation of mobility, the charge amount of ions and ink particles, and the interactions of particles with the electrode and inter-particles. The mobility of the ink particles was measured from the slopes of these peak voltages as functions of the square root of the time rate of the scanning voltage. The offset of line extrapolation indicated the interaction of the particles with the electrode. The optical response was effective for measuring the mobility even when the conductivity of the cell was too large to detect the drift current peaks.

  13. Effect of detailed power system models in traditional and voltage-stability-constrained optimal power-flow problems

    Microsoft Academic Search

    William D. Rosehart; Claudio A. Cañizares; Victor H. Quintana

    2003-01-01

    In this paper, detailed generator, exponential load, and static volt-ampere-reactive (VAr) compensator models are incorporated into traditional and voltage-stability-constrained optimal power-flow problems to study the effect that the different models have on costs and system-loadability. The proposed models are compared to typical models by means of a detailed analysis of the results obtained for two IEEE test systems; interior point

  14. Fuzzy based coordinated controller for power system stability and voltage regulation

    Microsoft Academic Search

    N. Yadaiah; A. Ganga Dinesh Kumar; J. L. Bhattacharya

    2004-01-01

    This paper deals with the design of a fuzzy based coordinated controller to prevent an electric power system losing synchronism after a large sudden fault and to achieve good post-fault voltage level. The developed controller has a fuzzy logic unit (FLU) which, accepts change in terminal voltage and speed deviation as its inputs and generates the required weightage for the

  15. Fluorinated polymer-grafted organic dielectrics for organic field-effect transistors with low-voltage and electrical stability.

    PubMed

    Kim, Kyunghun; Kim, Haekyoung; Kim, Se Hyun; Park, Chan Eon

    2015-06-24

    The electrical stabilities of low-voltage organic field-effect transistors (OFETs) were improved by applying graftable fluorinated polymer (gPFS) layers onto poly(4-vinyl phenol)-based cross-linked dielectrics (cPVP). As a result, a smooth and hydrophobic surface was formed, and the dielectric film displayed a low-leakage current density. The chemisorbed gPFS groups enabled the solution processing of an overlying 5,11-bis(triethylsilylethynyl)anthradithiophene semiconductor, which formed favorable terrace-like crystalline structures after solvent annealing. The top-contact OFETs showed superior operational stability compared to cPVP-based OFETs. Hysteresis was negligible, and the off-current of the transfer curve was one order of magnitude lower than that obtained from cPVP-based OFETs. The threshold voltage shift measured after a sustained gate bias stress for 1 h decreased significantly after introduction of the hydrophobic gPFS treatment; the energetic barrier to creating charge trapping sites increased, and the trap distribution narrowed, as supported by the stretched exponential function model. PMID:26059493

  16. Evaluation of Niobium as Candidate Electrode Material for DC High Voltage Photoelectron Guns

    NASA Technical Reports Server (NTRS)

    BastaniNejad, M.; Mohamed, Abdullah; Elmustafa, A. A.; Adderley, P.; Clark, J.; Covert, S.; Hansknecht, J.; Hernandez-Garcia, C.; Poelker, M.; Mammei, R.; Surles-Law, K.; Williams, P.

    2012-01-01

    The field emission characteristics of niobium electrodes were compared to those of stainless steel electrodes using a DC high voltage field emission test apparatus. A total of eight electrodes were evaluated: two 304 stainless steel electrodes polished to mirror-like finish with diamond grit and six niobium electrodes (two single-crystal, two large-grain, and two fine-grain) that were chemically polished using a buffered-chemical acid solution. Upon the first application of high voltage, the best large-grain and single-crystal niobium electrodes performed better than the best stainless steel electrodes, exhibiting less field emission at comparable voltage and field strength. In all cases, field emission from electrodes (stainless steel and/or niobium) could be significantly reduced and sometimes completely eliminated, by introducing krypton gas into the vacuum chamber while the electrode was biased at high voltage. Of all the electrodes tested, a large-grain niobium electrode performed the best, exhibiting no measurable field emission (< 10 pA) at 225 kV with 20 mm cathode/anode gap, corresponding to a field strength of 18:7 MV/m.

  17. Evaluation of the piezoelectric properties and voltage generation of flexible zinc oxide thin films.

    PubMed

    Laurenti, M; Stassi, S; Lorenzoni, M; Fontana, M; Canavese, G; Cauda, V; Pirri, C F

    2015-05-29

    Local piezoresponse and piezoelectric output voltage were evaluated on ZnO thin films deposited by radio-frequency magnetron sputtering on hard Si/Ti/Au and flexible Cu-coated polyimide substrates. Three different thicknesses of ZnO films were studied (285 nm, 710 nm, and 1380 nm), focusing on characteristics like crystallinity, grain size, surface roughness, and morphology. Independent of the nature of the metal layer and the substrate, our results show that thicker films presented a higher level of crystallinity and a preferential orientation along the c-axis direction, as well as a lower density of grain boundaries and larger crystal sizes. The improvement of the crystalline structure of the material directly enhances its piezoelectric properties, as confirmed by the local characterizations performed by piezoresponse force microscopy and by the evaluation of the output voltage generation under the application of a periodical mechanical deformation on the whole film. In particular, the highest value of the d33 coefficient obtained (8 pm V(-1)) and the highest generated output voltage (0.746 V) belong to the thickest films on hard and flexible substrates, respectively. These results envision the use of ZnO thin films-particularly on flexible substrates-as conformable, reliable, and efficient active materials for use in nanosensing, actuation, and piezoelectric nanogenerators. PMID:25943118

  18. Enhancement of Transient Stability Limit and Voltage Regulation with Dynamic Loads Using Robust Excitation Control

    NASA Astrophysics Data System (ADS)

    Hossain, Jahangir; Mahmud, Apel; Roy, Naruttam K.; Pota, Hemanshu R.

    2013-10-01

    In stressed power systems with large induction machine component, there exist undamped electromechanical modes and unstable monotonic voltage modes. This article proposes a sequential design of an excitation controller and a power system stabiliser (PSS) to stabilise the system. The operating region, with induction machines in stressed power systems, is often not captured using a linearisation around an operating point, and to alleviate this situation a robust controller is designed which guarantees stable operation in a large region of operation. A minimax linear quadratic Gaussian design is used for the design of the supplementary control to automatic voltage regulators, and a classical PSS structure is used to damp electromechanical oscillations. The novelty of this work is in proposing a method to capture the unmodelled nonlinear dynamics as uncertainty in the design of the robust controller. Tight bounds on the uncertainty are obtained using this method which enables high-performance controllers. An IEEE benchmark test system has been used to demonstrate the performance of the designed controller.

  19. Evaluation of the performance of polypropylene fibers on soil stabilization 

    E-print Network

    Sangineni, Srinivas Meherji

    1992-01-01

    EVALUATION OF THE PERFORMANCE OF POLYPROPYLENE FIBERS ON SOIL STABILIZATION A Thesis by SRINIVAS MEHERJI SANGINENI Submitted to the Office of Graduate Studies of Texas A&M University in partial fulfillment of the requirements for the degree... of MASTER OF SCIENCE December 1992 Major Subject: Civil Engineering EVALUATION OF THE PERFORMANCE OF POLYPROPYLENE FIBERS ON SOIL STABILIZATION A Thesis by SRINIVAS MEHERJI SANGINENI Approved as to style and content by: Dallas bL Little (Chair...

  20. Pressure dependence of the negative bias voltage for stabilization of cubic boron nitride thin films deposited by sputtering

    NASA Astrophysics Data System (ADS)

    Otaño-Rivera, Wilfredo; Pilione, Lawrence J.; Messier, Russell

    1998-05-01

    Thin films of boron nitride were deposited by unbalanced magnetron sputtering at pressures between 0.065 and 1.32 Pa in order to study the effects of pressure and negative substrate bias on the energy of the bombarding plasma ions and subsequent stabilization of the cubic phase. It was found that the threshold bias voltage for nucleation of films with a high percentage of the cubic phase increases with the product of the pressure and sheath thickness. This trend is explained in terms of the changes in the average energy of the particles bombarding the growing film produced by pressure-dependent charge-exchange collisions in the plasma/substrate sheath. This energy modification process has predictable consequences in complex deposition processes.

  1. DEVELOPMENT OF STABILITY EVALUATION METHOD OF RAILWAY LEANING RETAINING WALLS

    NASA Astrophysics Data System (ADS)

    Shinoda, Masahiro; Nakajima, Susumu; Abe, Keita

    Conventionally, an inspection method to evaluate stability of railway retaining walls is basically visual inspection. This is because there is no quantitative inspection method. Therefore, a percussion test which is commonly applied to bridge substructures to check its stability was applied to the leaning retaining walls for investigation of their frequency characteristics. Subsequently, to indentify the relationships between the integrity and frequency characteristics of the retaining walls, a series of model tests was conducted. Consequently, a newly developed stability inspection and evaluation methods were presented, and successfully verified to apply to existing leaning retaining walls.

  2. Organic-silicon heterojunction solar cells: Open-circuit voltage potential and stability

    NASA Astrophysics Data System (ADS)

    Schmidt, Jan; Titova, Valeriya; Zielke, Dimitri

    2013-10-01

    We characterize the electronic properties of crystalline silicon (c-Si)/poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) junctions by means of contactless carrier lifetime measurements. The measurements demonstrate that this type of heterojunction has an unexpectedly high open-circuit voltage (Voc) potential exceeding 690 mV, making it relevant for the implementation into high-efficiency c-Si solar cells. Hybrid n-type c-Si solar cells featuring a PEDOT:PSS hole-transport layer on the front reach an energy conversion efficiency of 12.3%. We observe a humidity-related degradation in cell efficiency during storage in air. The degradation is reduced by capping the entire device by an atomic-layer-deposited aluminum oxide film and is completely avoided in a dehumidified environment.

  3. Numerical simulation study on earthquake-induced landslide stability evaluation

    NASA Astrophysics Data System (ADS)

    Li, C.; Tang, H.; Wang, L.; Xiong, C.

    2009-12-01

    Landslide is one of the most dangerous geological hazards in the world, and its stability is affected by many factors. Especially in the earthquake-prone area, the earthquake plays a quite significant role in the stability evaluation of landslide. A typical landslide in Western China area was taken as an example, from which the geological model of landslide with considering the earthquake effect was established. The dynamic analysis module of finite difference software FLAC3D was carried out the numerical simulation in order to evaluate the stability of the landslide under the condition of earthquake effect. The result indicates that the numerical simulation analysis is in concordance with the engineering practice of the landslide. This study can provided a significant scientific basis for the stability evaluation of landslide in earthquake-prone area of Western China.

  4. Evaluation of Contribution for Voltage Control Ancillary Services Based on Social Surplus

    NASA Astrophysics Data System (ADS)

    Ueki, Yuji; Hara, Ryoichi; Kita, Hiroyuki; Hasegawa, Jun

    Reactive power supply plays an important role in active power supply with adequate system voltages. Various pricing mechanism for reactive power supply have been developed and some of them are adopted in some power systems, however they are in a trial stage. The authors also focus on development of a pricing method for reactive power ancillary services. This problem involves two technical issues: rational estimation of the cost associated with reactive power supply and fair and transparent allocation of the estimated cost among the market participants. This paper proposes methods for evaluating the contribution of generators and demands.

  5. Fuzzy PID Controller Design for PWM-Buck EBW Stabilized High-Voltage Source Using Saber-Matlab Co-simulation

    Microsoft Academic Search

    Jinhai Mol; Shaojia He; Yunping Zou

    2007-01-01

    A novel PWM-buck type EBW (electron beam welder) stabilized high-voltage source circuit system is introduced, in which an inductance current-limiting circuit is attached to prevent surge and over current thus increasing the system's working reliability and stability. Due to its strong non-linearity and large signal working condition, it is difficult to reach a relatively satisfactory performance with a conventional PID

  6. Stability evaluation of rockfall based on AHP-Fuzzy method

    Microsoft Academic Search

    Siqiao Ye; Hongmei Tang; hongkai Chen; hui Zhu

    2010-01-01

    The development of rockfall has complicated, multifactorial, fuzzy and uncertain characters. Based on analysis of rockfall development factors, the authors quantified the weighting matrix of these factors using AHP model. And then the weighting matrix was introduced into fuzzy integrative evaluation. By combining the AHP method with fuzzy theory, the authors presented the AHP-Fuzzy methd for stability evaluation of rockfall.

  7. [Clinical evaluation of the voltage gradient method for root canal measurement].

    PubMed

    Nakamura, M; Nakamura, Y

    1989-10-01

    The voltage gradient method for root canal measurement was evaluated in vivo and in vitro. For the evaluation in vivo, 25 single root teeth, were employed. The working length was measured by bipolor or monopolor electrode. After measurement, the electrode was fixed on the tooth, and the tooth was extracted. Radiograph was taken from 12 directions perpendicular to longer axis of tooth, and the relation between anatomical foramen, physiological foramen and the attained position of electrode tip was assessed. In the evaluation in vitro, 7 extracted teeth were used, for which the positions of anatomical foramen and physiological foramen had been determined in advance from radiograph, in order to determine the influence of the root canal irrigants and medicaments. The electrode was fixed on electronic calipers and direct reading of the movement. Root canal irrigants and medicaments were injected into root canal, and the measurements were evaluated. The results were as follows: (1) In the cases of 22 teeth measured by monopolar electrode in vivo, the electrode tip was within 0.5mm from physiological foramen except one tooth. (2) In the cases of 3 teeth measured by monopolar electrode in vivo, the electrode tip was within 0.4mm from anatomical foramen. (3) In the cases, where electrolyte solution was filled in root canal and measurement was made by bipolar in the evaluation in vitro, the results of measurement were stable, and the electrode tip tended to be slightly closer to coronal direction from physiological foramen. (4) In the cases where non-electrolyte solution was filled in root canal and measurement was made by bipolar electrode in the evaluation in vitro, the results of measurement were not stable, and the electrode tip tended to be closer to the apex from physiological foramen. (5) In the case of the evaluation in vitro, where electrolyte solution was filled in root canal and measurement was made by monopolar electrode, the electrode tip tended to be a little closer to the front than the anatomical foramen. (6) In the evaluation in vitro, where non-electrolyte solution was filled in root canal and measurement was made by monopolar, the measurement was not achievable. (7) 10% NaOCl solution was found to be very useful as electrolyte solution filled in root canal to search physiological foramen by this measurement method. The above results suggest that the voltage gradient method for root canal measurement is highly reliable because root canal morphology at the apex can be directly in identified. PMID:2489340

  8. Evaluation of electropolished stainless steel electrodes for use in DC high voltage photoelectron guns

    DOE PAGESBeta

    BastaniNejad, Mahzad; Elmustafa, Abdelmageed A.; Forman, Eric; Covert, Steven; Hansknecht, John; Hernandez-Garcia, Carlos; Poelker, Matthew; Das, Lopa; Kelley, Michael; Williams, Phillip

    2015-07-01

    DC high voltage photoelectron guns are used to produce polarized electron beams for accelerator-based nuclear and high-energy physics research. Low-level field emission (?nA) from the cathode electrode degrades the vacuum within the photogun and reduces the photoelectron yield of the delicate GaAs-based photocathode used to produce the electron beams. High-level field emission (>?A) can cause significant damage the photogun. To minimize field emission, stainless steel electrodes are typically diamond-paste polished, a labor-intensive process often yielding field emission performance with a high degree of variability, sample to sample. As an alternative approach and as comparative study, the performance of electrodes electropolishedmore »by conventional commercially available methods is presented. Our observations indicate the electropolished electrodes exhibited less field emission upon the initial application of high voltage, but showed less improvement with gas conditioning compared to the diamond-paste polished electrodes. In contrast, the diamond-paste polished electrodes responded favorably to gas conditioning, and ultimately reached higher voltages and field strengths without field emission, compared to electrodes that were only electropolished. The best performing electrode was one that was both diamond-paste polished and electropolished, reaching a field strength of 18.7 MV/m while generating less than 100?pA of field emission. The authors speculate that the combined processes were the most effective at reducing both large and small scale topography. However, surface science evaluation indicates topography cannot be the only relevant parameter when it comes to predicting field emission performance.« less

  9. Evaluation of a 125I-labelled benzazepinone derived voltage-gated sodium channel blocker for imaging with SPECT.

    PubMed

    Pérez-Medina, Carlos; Patel, Niral; Robson, Mathew; Badar, Adam; Lythgoe, Mark F; Årstad, Erik

    2012-12-21

    Voltage-gated sodium channels (VGSCs) are a family of transmembrane proteins that mediate fast neurotransmission, and are integral to sustain physiological conditions and higher cognitive functions. Imaging of VGSCs in vivo holds promise as a tool to elucidate operational functions in the brain and to aid the treatment of a wide range of neurological diseases. To assess the suitability of 1-benzazepin-2-one derived VGSC blockers for imaging, we have prepared a (125)I-labelled analogue of BNZA and evaluated the tracer in vivo. In an automated patch-clamp assay, a diastereomeric mixture of the non-radioactive compound blocked the Na(v)1.2 and Na(v)1.7 VGSC isoforms with IC(50) values of 4.1 ± 1.5 ?M and 0.25 ± 0.07 ?M, respectively. [(3)H]BTX displacement studies revealed a three-fold difference in affinity between the two diastereomers. Iodo-destannylation of a tin precursor with iodine-125 afforded the two diastereomerically pure tracers, which were used to assess binding to VGSCs in vivo by comparing their tissue distributions in mice. Whilst the results point to a lack of VGSC binding in vivo, SPECT imaging revealed highly localized uptake in the interscapular region, an area typically associated with brown adipose tissue, which in addition to high metabolic stability of the iodinated tracer, demonstrate the potential of 1-benzazepin-2-ones for in vivo imaging. PMID:23117159

  10. Voltage sag detection based on rectified voltage processing

    Microsoft Academic Search

    Andrea Florio; Andrea Mariscotti; Maurizio Mazzucchelli

    2004-01-01

    An algorithm for voltage sag detection based on rectified voltage processing is presented and its performances are evaluated by means of simulated and real voltage waveforms (recorded at some low-voltage busbars and measured on a scaled prototype of a voltage support system). The algorithm is intended to detect voltage sag occurrence and to trigger the disconnection of the faulty supply

  11. Evaluation of electronic stability control effectiveness in Australasia

    Microsoft Academic Search

    Jim Scully; Stuart Newstead

    2008-01-01

    Electronic stability control (ESC) is an in-vehicle technology aimed at improving primary safety by assisting the driver in avoiding loss of control of the vehicle. The aim of this study was to use available crash data from Australia and New Zealand to evaluate the effectiveness of ESC in reducing crash risk and to establish whether benefits estimated from overseas studies

  12. Stability evaluation of the Markel Mine at Weeks Island, Louisiana

    SciTech Connect

    Hoffman, E.L.

    1994-06-01

    A three dimensional (3D) finite element analysis of the Markel Mine located on Weeks Island was performed to: (1) evaluate the stability of the mine and (2) determine the effect of mine failure on the nearby Morton Salt mine and SPR facilities. The first part of the stability evaluation investigates the effect of pillar failure on mine stability. These simulations revealed that tensile stresses and dilatant damage develop in the overlying salt as a result of pillar loss. These tensile stresses extend to the salt/overburden interface only for the case where all 45 of the pillars are assumed to fail. Tensile stresses would likely cause microfracturing of the salt, resulting in a flow path for groundwater from the overlying aquifer to enter the mine. The dilatant damage bridges between the mine and the overburden in the case where 15 or more pillars are removed from the model. Dilatant damage is attributed to microfracturing or changes in the pore structure of the salt and could also result in a flow path for groundwater to enter the mine. The second part of the Markel Mine evaluation investigates the stability of the pillars with respect to three failure mechanisms: tensile failure, compressive failure, and creep rupture. A 3D slabbing pillar model of the Markel mine was developed to investigate progressive failure of the pillars and the effect of slabbing on mine stability. Based on a strain-limiting creep rupture criterion, pillar failure is predicted to be extensive at present. The associated loss of pillar strength should be equivalent to removing all pillars from the model as was done in the first part of this stability analysis, resulting in the possibility of ground water intrusion. Since creep rupture is not a well understood phenomenon, further development and validation of this criterion is recommended.

  13. Evaluation of the input current quality by three different modulation strategies for SVM controlled matrix converters with input voltage unbalance

    Microsoft Academic Search

    Peter Nielsen; Domenico Casadei; Giovanni Serra; Angelo Tani

    1996-01-01

    A new input current modulation strategy for a matrix power converter is presented. The performance of the new strategy during input voltage unbalance is compared to two other strategies. The difference of the three modulations only concerns the detection of the reference angle for the input current vector. The input current quality is evaluated using four different criteria. It is

  14. Voltage Divider

    NSDL National Science Digital Library

    This voltage divider produces an output voltage, Vo, that is proportional to the input voltage, Vs. The output voltage is measured using a voltmeter. The input voltage is the voltage of the voltage source. The constant of proportionality is called the gain of the voltage divider. The value of the gain of the voltage divider is determined by the resistances, R1 and R2, of the two resistors that comprise the voltage divider.

  15. A novel neutral point potential stabilization technique using the information of output current polarities and voltage vector

    Microsoft Academic Search

    Katsutoshi Yamanaka; Ahmet M. Hava; Hiroshi Kirino; Yoshiyuki Tanaka; Noritaka Koga; Tsuneo Kume

    2002-01-01

    This paper proposes a new neutral point potential control technique for the neutral-point-clamped three-level inverter. Utilizing the phase current polarity information, this technique distributes the redundant voltage vectors in a manner to obtain stable neutral point voltage under all operating conditions including the zero-power-factor condition. Detailed analysis and computer simulations show the superiority of the proposed method. The feasibility of

  16. Statistical Evaluation of Voltage Variation of Power Distribution System with Clustered Home-Cogeneration Systems

    NASA Astrophysics Data System (ADS)

    Kato, Takeyoshi; Minagata, Atsushi; Suzuoki, Yasuo

    This paper discusses the influence of mass installation of a home co-generation system (H-CGS) using a polymer electrolyte fuel cell (PEFC) on the voltage profile of power distribution system in residential area. The influence of H-CGS is compared with that of photovoltaic power generation systems (PV systems). The operation pattern of H-CGS is assumed based on the electricity and hot-water demand observed in 10 households for a year. The main results are as follows. With the clustered H-CGS, the voltage of each bus is higher by about 1-3% compared with the conventional system without any distributed generators. Because H-CGS tends to increase the output during the early evening, H-CGS contributes to recover the voltage drop during the early evening, resulting in smaller voltage variation of distribution system throughout a day. Because of small rated power output about 1kW, the influence on voltage profile by the clustered H-CGS is smaller than that by the clustered PV systems. The highest voltage during the day time is not so high as compared with the distribution system with the clustered PV systems, even if the reverse power flow from H-CGS is allowed.

  17. Evaluating Throughput Stability of Protocols for Distributed Middleware

    NASA Astrophysics Data System (ADS)

    Carvalho, Nuno A.; Oliveira, José P.; Pereira, José

    Communication of large data volumes is a core functionality of distributed systems middleware, namely, for interconnecting components, for distributed computation and for fault tolerance. This common functionality is however achieved in different middleware platforms with various combinations of operating system and application level protocols, both standardized and ad hoc, and including implementations on managed runtime environments such as Java. In this paper, in contrast with most previous work that focus on performance, we point out that architectural and implementation decisions have an impact in throughput stability when the system is heavily loaded, precisely when such stability is most important. In detail, we present an experimental evaluation of several communication protocol components under stress conditions and conclude on the relative merits of several architectural options.

  18. A comprehensive study to evaluate the effect of constant low voltage iontophoresis on transungual delivery.

    PubMed

    Nair, Anroop B; Singh, Kishan; Shinu, Pottathil; Harsha, Sree; Al-Dhubiab, Bandar E

    2013-05-01

    Treatment of nail diseases by topical drug delivery continues to draw much attention in the recent days. This study aims to systematically investigate the effect of constant voltage iontophoresis in the transungual drug delivery, using ciclopirox as a model drug. Preliminary permeation studies were carried out by applying constant voltage (6 V for 24 h) using a gel formulation across the human nail plate in a Franz diffusion cell. Different protocols have been studied to authenticate the potential of the proposed technique. Antifungal studies were carried out to assess the pharmacodynamic effect of drug depot formed in the nail plate. Initial studies revealed that application of constant voltage iontophoresis enhanced the permeation by an order of magnitude (p = 0.019) and delivered significant amount of drug into the deeper nail layers. Noticeably higher permeation was observed during the active phase in on-off studies. Excellent correlation was observed in permeation (r(2) = 0.98) and drug load (r(2) = 0.97) with the increase in applied voltage (3-12 V), indicating that the current technique is predictable. The data observed suggest that any further increase in voltage could eventually lead to increase in the permeation and drug load, as the saturation level is very distant. Furthermore, the enhancement in permeation with the applied voltage (3-12 V) was found to be 6-20 folds, compared to the passive process. Results of step up and step down studies substantiated the viability of the current technique. Zone of inhibition measured during the antifungal studies demonstrated that the drug molecules loaded into the nail plate by low voltage iontophoresis is active and releases over an extended period of time (~32 days). Given the excellent results, the current technique could be used as an effective approach for the delivery of antimycotics, which would localize the drug at the infection site and potentially offer higher patient compliance. PMID:23057692

  19. Optical voltage reference

    DOEpatents

    Rankin, R.; Kotter, D.

    1994-04-26

    An optical voltage reference for providing an alternative to a battery source is described. The optical reference apparatus provides a temperature stable, high precision, isolated voltage reference through the use of optical isolation techniques to eliminate current and impedance coupling errors. Pulse rate frequency modulation is employed to eliminate errors in the optical transmission link while phase-lock feedback is employed to stabilize the frequency to voltage transfer function. 2 figures.

  20. Optical voltage reference

    DOEpatents

    Rankin, Richard (Ammon, ID); Kotter, Dale (Bingham County, ID)

    1994-01-01

    An optical voltage reference for providing an alternative to a battery source. The optical reference apparatus provides a temperature stable, high precision, isolated voltage reference through the use of optical isolation techniques to eliminate current and impedance coupling errors. Pulse rate frequency modulation is employed to eliminate errors in the optical transmission link while phase-lock feedback is employed to stabilize the frequency to voltage transfer function.

  1. Evaluation of higher distribution and/or utilization voltages. Final report

    SciTech Connect

    Hazelrigg, Jr, George A.

    1981-01-01

    An electric energy distribution/utilization system cost analysis model is presented for exploring cost tradeoffs (capital innvestment, operation and maintenance and cost of losses) and optimizing system configuration. The model focuses on the treatment of residential and light commercial service areas with time-varying load characteristics, including customer load profile changes, per customer load growth and service area population growth. Applications of the model are discussed. These include providing insight on: the selection of primary and secondary voltages; conductor sizing; distribution transformer sizing, change out policies and copper-to-core-loss ratio; and limits on allowable voltage variation at the service entrance. Examples are provided to illustrate model capabilities.

  2. Effects of Sample Storage on Biosolids Compost Stability and Maturity Evaluation

    E-print Network

    Ma, Lena

    Effects of Sample Storage on Biosolids Compost Stability and Maturity Evaluation L. Wu and L. Q. Ma-drying of soil sam-Compost stability and maturity are important parameters of com- ples is the most common of soil may can affect compost stability and maturity evaluation. However, sample significantly alter

  3. Voltage stability analysis of an Urban Distribution Network (UDN) with high penetration of combined heat & Power (CHP) generation

    Microsoft Academic Search

    Sreto Boljevic; Michael F. Conlon

    2010-01-01

    The capacity of Combined Heat and Power (CHP) generation connected to Urban Distribution Network (UDN) will increase significantly as a result of EU government targets and initiatives. CHP generators can have a significant impact on the power flow, voltage profile and the power quality for customers and electricity suppliers. The connection of CHP plant at UDN creates a number of

  4. Voltage Stabilization in Microgrids via Quadratic Droop Control John W. Simpson-Porco, Florian Dorfler, and Francesco Bullo

    E-print Network

    Bullo, Francesco

    , and validate the robustness of our design through simulation. I. IN T RO D U C T I O N Due to environmental and social factors, and the rapidly expanding integration of low voltage small-scale renewable energy sources autonomously from the larger primary network. Microgrids are able to connect to the wide area electric power

  5. Multiobjective optimal power flows to evaluate voltage security costs in power networks

    Microsoft Academic Search

    William D. Rosehart; Claudio A. Cañizares; Victor H. Quintana

    2003-01-01

    In this paper, new optimal power flow (OPF) techniques are proposed based on multiobjective methodologies to optimize active and reactive power dispatch while maximizing voltage security in power systems. The use of interior point methods together with goal programming and linearly combined objective functions as the basic optimization techniques are explained in detail. The effects of minimizing operating costs, minimizing

  6. Stability analysis and experimental evaluation of a matrix converter drive system

    Microsoft Academic Search

    Furong Liu; C. Klumpner; Frede Blaabjerg

    2003-01-01

    The interest in using the matrix converter (MC) technology for motor drive applications is steadily increasing due to its advantages: high quality of the input currents, regeneration capability and high power density but a few unsolved issues delays its industrial use. This paper deals with one of them: the stability of a MC drive caused by using the voltage across

  7. Evaluation of voltage-sensitive fluorescence dyes for monitoring neuronal activity in the embryonic central nervous system

    PubMed Central

    Mullah, Saad Habib-E-Rasul; Komuro, Ryo; Yan, Ping; Hayashi, Shihori; Inaji, Motoki; Momose-Sato, Yoko; Loew, Leslie M.; Sato, Katsushige

    2014-01-01

    Using an optical imaging technique with voltage-sensitive dyes (VSDs), we have been investigating the functional organization and architecture of the central nervous system (CNS) during embryogenesis. In the embryonic nervous system, a merocyanine-rhodanine dye, NK2761, has proved to be the most useful absorption dye for detecting neuronal activity because of its high signal-to-noise ratio (S/N), low toxicity, and small dye bleaching. In the present study, we evaluated the suitability of voltage-sensitive fluorescence dyes for optical recording in the embryonic CNS. We screened eight styryl (hemicyanine) dyes in isolated brainstem-spinal cord preparations from 7-day old chick embryos. Measurements of voltage-related optical signals were made using a multiple-site optical recording system. The signal size, S/N, photobleaching, effects of perfusion, and recovery of neural responses after staining were compared. We also evaluated optical responses with various magnifications. Although the S/N was lower than with the absorption dye, clear optical responses were detected with several fluorescence dyes, including di-2-ANEPEQ, di-4-ANEPPS, di-3-ANEPPDHQ, di-4-AN(F)EPPTEA, di-2-AN(F)EPPTEA, and di-2-ANEPPTEA. Di-2-ANEPEQ showed the largest S/N, whereas its photobleaching was faster and the recovery of neural responses after staining was slower. Di-4-ANEPPS and di-3-ANEPPDHQ also exhibited a large S/N, but required a relatively long time for recovery of neural activity. Di-4-AN(F)EPPTEA, di-2-AN(F)EPPTEA, and di-2-ANEPPTEA showed smaller S/Ns than di-2-ANEPEQ, di-4-ANEPPS, and di-3-ANEPPDHQ, but the recovery of neural responses after staining was faster. This study demonstrates the potential utility of these styryl dyes in optical monitoring of voltage changes in the embryonic CNS. PMID:23975337

  8. A whole soil stability index (WSSI) for evaluating soil aggregation

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Soil aggregate stability is an indicator of soil quality. However, there is no standard methodology for measuring soil aggregation or aggregate stability, particularly for determining a whole soil stability index. A whole soil stability index (WSSI) was developed here which combined data from dry ...

  9. Technical evaluation report on the proposed design modifications and technical-specification changes on grid voltage degradation for the San Onofre Nuclear Genetating Station, Unit 1

    SciTech Connect

    Selan, J.C.

    1982-05-26

    This report documents the technical evaluation of the proposed design modifications and Technical Specification changes for protection of Class 1E equipment from grid voltage degradation for the San Onofre Nuclear Generating Station, Unit 1. The review criteria are based on several IEEE standards and the Code of Federal Regulations. The evaluation finds that the proposed design modifications and Technical Specification changes will ensure that the Class 1E equipment will be protected from sustained voltage degradation.

  10. Interference Evaluation of Overhead Medium-Voltage Broadband Power Line Systems

    Microsoft Academic Search

    Song Liu; Larry J. Greenstein

    2010-01-01

    We analyze the radio interference from a broadband power line (BPL) system operating between 2 MHz and several tens of megahertz. The overhead medium-voltage power line is modeled as a three-phase set of parallel wires above a lossy earth. A near-exact solution, based on previous approaches for infinitely long lines, is presented for the fields from arbitrarily long lines. A

  11. Evaluation of high-voltage cable-coupler performance for mine power systems. [Ph. D. Thesis

    Microsoft Academic Search

    Bise

    1980-01-01

    High-voltage cable couplers are convenient and widely used accessories in modern coal-mine power distribution systems for aiding in the extension and retraction of power-feeder cables throughout a mine. Coupler design has tried to keep pace with the industry's desire to move to higher distribution levels, but the increase in recorded failures of 15-kV-class couplers, which serve the distribution levels of

  12. CT x-ray tube voltage optimisation and image reconstruction evaluation using visual grading analysis

    NASA Astrophysics Data System (ADS)

    Zheng, Xiaoming; Kim, Ted M.; Davidson, Rob; Lee, Seongju; Shin, Cheongil; Yang, Sook

    2014-03-01

    The purposes of this work were to find an optimal x-ray voltage for CT imaging and to determine the diagnostic effectiveness of image reconstruction techniques by using the visual grading analysis (VGA). Images of the PH-5 CT abdomen phantom (Kagaku Co, Kyoto) were acquired by the Toshiba Aquillion One 320 slices CT system with various exposures (from 10 to 580 mAs) under different tube peak voltages (80, 100 and 120 kVp). The images were reconstructed by employing the FBP and the AIDR 3D iterative reconstructions with Mild, Standard and Strong FBP blending. Image quality was assessed by measuring noise, contrast to noise ratio and human observer's VGA scores. The CT dose index CTDIv was obtained from the values displayed on the images. The best fit for the curves of the image quality VGA vs dose CTDIv is a logistic function from the SPSS estimation. A threshold dose Dt is defined as the CTDIv at the just acceptable for diagnostic image quality and a figure of merit (FOM) is defined as the slope of the standardised logistic function. The Dt and FOM were found to be 5.4, 8.1 and 9.1 mGy and 0.47, 0.51 and 0.38 under the tube voltages of 80, 100 and 120 kVp, respectively, from images reconstructed by the FBP technique. The Dt and FOM values were lower from the images reconstructed by the AIDR 3D in comparison with the FBP technique. The optimal xray peak voltage for the imaging of the PH-5 abdomen phantom by the Aquillion One CT system was found to be at 100 kVp. The images reconstructed by the FBP are more diagnostically effective than that by the AIDR 3D but with a higher dose Dt to the patients.

  13. An evaluation of mitigation techniques for bearing currents, EMI and over-voltages in ASD applications

    Microsoft Academic Search

    Annette von Jouanne; Haoran Zhang; Alan Wallace

    1997-01-01

    With the increased application of adjustable speed drives (ASDs) for the efficient speed control of AC motors, there has been a growing number of costly motor-drive related process failures. The popular ASDs consist of a pulse-width modulated (PWM) inverter switching insulated gate bipolar transistors (IGBTs) at 2 to 20 kHz, with rates of voltage rise (dv\\/dt) of 6000 V\\/?s. The

  14. Evaluating Sediment Stability at Offshore Marine Hydrokinetic Energy Facilities

    NASA Astrophysics Data System (ADS)

    Jones, C. A.; Magalen, J.; Roberts, J.; Chang, G.

    2014-12-01

    Development of offshore alternative energy production methods through the deployment of Marine Hydrokinetic (MHK) devices (e.g. wave, tidal, and wind generators) in the United States continues at a rapid pace, with significant public and private investment in recent years. The installation of offshore MHK systems includes cabling to the shoreline and some combination of bottom foundation (e.g., piles, gravity bases, suction buckets) or anchored floating structure. Installation of any of this infrastructure at the seabed may affect coastal sediment dynamics. It is, therefore, necessary to evaluate the interrelationships between hydrodynamics and seabed dynamics and the effects of MHK foundations and cables on sediment transport. If sufficient information is known about the physical processes and sediment characteristics of a region, hydrodynamic and sediment transport models may be developed to evaluate near and far-field sediment transport. The ultimate goal of these models and methods is to quantitatively evaluate changes to the baseline seabed stability due to the installation of MHK farms in the water. The objective of the present study is to evaluate and validate wave, current, and sediment transport models (i.e., a site analysis) that may be used to estimate risk of sediment mobilization and transport. While the methodology and examples have been presented in a draft guidance document (Roberts et al., 2013), the current report presents an overall strategy for model validation, specifically for a case study in the Santa Cruz Bight, Monterey Bay, CA. Innovative techniques to quantify the risk of sediment mobility has been developed to support these investigations. Public domain numerical models are utilized to estimate the near-shore wave climate (SWAN: Simulating Waves Near-shore) and circulation and sediment transport (EFDC: Environmental Fluid Dynamics Code) regimes. The models were validated with field hydrodynamic data. Sediment size information was provided by the USGS usSEABED sediment database program. Near-bottom current- and wave-induced shear stresses were computed and used directly to derive a sediment mobilization risk relationship.

  15. Benchmarking the stability of human detergent-solubilised voltage-gated sodium channels for structural studies using eel as a reference.

    PubMed

    Slowik, Daria; Henderson, Richard

    2015-07-01

    With the ultimate goal of detailed structural analysis of mammalian and particularly human voltage-gated sodium channels (VGSCs), we have investigated the relative stability of human and rat VGSCs and compared them with electric eel VGSC. We found that NaV1.3 from rat was the most stable after detergent solubilisation. The order of stability was rNaV1.3>hNaV1.2>hNaV1.1>hNaV1.6>hNaV1.3>hNaV1.4. However, a comparison with the VGSC from Electrophorus electricus, which is most similar to NaV1.4, shows that the eel VGSC is considerably more stable in detergent than the human VGSCs examined. We conclude that current methods of structural analysis, such as single particle electron cryomicroscopy (cryoEM), may be most usefully targeted to eel VGSC or rNaV1.3, but that structural analysis on the full spectrum of VGSCs, by methods that require greater stability such as crystallisation and X-ray crystallography, will require further stabilisation of the channel. PMID:25838126

  16. Global Stability of Banking Networks Against Financial Contagion: Measures, Evaluations and

    E-print Network

    DasGupta, Bhaskar

    Global Stability of Banking Networks Against Financial Contagion: Measures, EvaluationsGupta (UIC) Global Stability of Banking Networks September 16, 2014 2 / 48 #12;Introduction financial) Global Stability of Banking Networks September 16, 2014 4 / 48 #12;Introduction Cause for financial

  17. HEMC: A sensitive aggregate stability method for soil quality evaluation

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Soil aggregate stability is an important soil quality index, representing mainly soil structural stability and affecting, among others, hydraulic conductivity, seal formation, runoff, water and wind erosion. The most common method of assessing aggregate stability is wet sieving where aggregate stabi...

  18. A high-stability scanning tunneling microscope achieved by an isolated tiny scanner with low voltage imaging capability.

    PubMed

    Wang, Qi; Hou, Yubin; Wang, Junting; Lu, Qingyou

    2013-11-01

    We present a novel homebuilt scanning tunneling microscope (STM) with high quality atomic resolution. It is equipped with a small but powerful GeckoDrive piezoelectric motor which drives a miniature and detachable scanning part to implement coarse approach. The scanning part is a tiny piezoelectric tube scanner (industry type: PZT-8, whose d31 coefficient is one of the lowest) housed in a slightly bigger polished sapphire tube, which is riding on and spring clamped against the knife edges of a tungsten slot. The STM so constructed shows low back-lashing and drifting and high repeatability and immunity to external vibrations. These are confirmed by its low imaging voltages, low distortions in the spiral scanned images, and high atomic resolution quality even when the STM is placed on the ground of the fifth floor without any external or internal vibration isolation devices. PMID:24289400

  19. A high-stability scanning tunneling microscope achieved by an isolated tiny scanner with low voltage imaging capability

    SciTech Connect

    Wang, Qi; Wang, Junting; Lu, Qingyou, E-mail: qxl@ustc.edu.cn [High Magnetic Field Laboratory, Chinese Academy of Sciences and University of Science and Technology of China, Hefei, Anhui 230026 (China) [High Magnetic Field Laboratory, Chinese Academy of Sciences and University of Science and Technology of China, Hefei, Anhui 230026 (China); Hefei National Laboratory for Physical Sciences at Microscale, University of Science and Technology of China, Hefei, Anhui 230026 (China); Hou, Yubin [High Magnetic Field Laboratory, Chinese Academy of Sciences and University of Science and Technology of China, Hefei, Anhui 230026 (China)] [High Magnetic Field Laboratory, Chinese Academy of Sciences and University of Science and Technology of China, Hefei, Anhui 230026 (China)

    2013-11-15

    We present a novel homebuilt scanning tunneling microscope (STM) with high quality atomic resolution. It is equipped with a small but powerful GeckoDrive piezoelectric motor which drives a miniature and detachable scanning part to implement coarse approach. The scanning part is a tiny piezoelectric tube scanner (industry type: PZT-8, whose d{sub 31} coefficient is one of the lowest) housed in a slightly bigger polished sapphire tube, which is riding on and spring clamped against the knife edges of a tungsten slot. The STM so constructed shows low back-lashing and drifting and high repeatability and immunity to external vibrations. These are confirmed by its low imaging voltages, low distortions in the spiral scanned images, and high atomic resolution quality even when the STM is placed on the ground of the fifth floor without any external or internal vibration isolation devices.

  20. A high-stability scanning tunneling microscope achieved by an isolated tiny scanner with low voltage imaging capability

    NASA Astrophysics Data System (ADS)

    Wang, Qi; Hou, Yubin; Wang, Junting; Lu, Qingyou

    2013-11-01

    We present a novel homebuilt scanning tunneling microscope (STM) with high quality atomic resolution. It is equipped with a small but powerful GeckoDrive piezoelectric motor which drives a miniature and detachable scanning part to implement coarse approach. The scanning part is a tiny piezoelectric tube scanner (industry type: PZT-8, whose d31 coefficient is one of the lowest) housed in a slightly bigger polished sapphire tube, which is riding on and spring clamped against the knife edges of a tungsten slot. The STM so constructed shows low back-lashing and drifting and high repeatability and immunity to external vibrations. These are confirmed by its low imaging voltages, low distortions in the spiral scanned images, and high atomic resolution quality even when the STM is placed on the ground of the fifth floor without any external or internal vibration isolation devices.

  1. Evaluation of electronic stability control effectiveness in Australasia.

    PubMed

    Scully, Jim; Newstead, Stuart

    2008-11-01

    Electronic stability control (ESC) is an in-vehicle technology aimed at improving primary safety by assisting the driver in avoiding loss of control of the vehicle. The aim of this study was to use available crash data from Australia and New Zealand to evaluate the effectiveness of ESC in reducing crash risk and to establish whether benefits estimated from overseas studies have translated to the Australian and New Zealand environments. The sample analysed included 7699 crashed vehicles fitted with ESC which comprised of 90 different models. Poisson regression was used to test whether the differences in the observed and expected crash counts for ESC fitted vehicles were significant, with exposure being induced from counts of rear end impacts. It was found that ESC reduced the risk of single vehicle crashes in which the driver was injured by 68% for 4WDs compared with 27% for passenger cars. The effect of ESC on multiple vehicle crashes in Australia and New Zealand was not clear. The long-term benefits of fitting ESC to all vehicles in Australia were also investigated based on the estimated single vehicle crash reductions. PMID:19068314

  2. Biomechanical Evaluation of Ligamentous Stabilizers of the Scaphoid and Lunate

    PubMed Central

    Short, Walter H.; Werner, Frederick W.; Green, Jason K.; Masaoka, Shunji

    2007-01-01

    This study evaluated the effects of sectioning the scapholunate interosseous ligament, radioscaphocapitate ligament, and scaphotrapezial ligament on the kinematics of the scaphoid and lunate. Eight cadaver upper extremities were placed in a wrist joint simulator and moved in continuous cycles of flexion-extension and radial-ulnar deviation. Positional data of the scaphoid and lunate were obtained in the intact state, after the scapholunate ligament was cut; after the scapholunate and scaphotrapezial ligaments were cut; after the scapholunate, scaphotrapezial, and radioscaphocapitate ligaments were cut; and after all 3 ligaments were cut and the specimen was placed through an additional 1,000 cycles of flexion-extension. Cutting the scapholunate ligament caused changes in scaphoid and lunate motion during flexion-extension, but not radial-ulnar deviation. Additional sectioning of the scaphotrapezial ligament followed by the radioscaphocapitate ligament caused further kinematic changes in these carpal bones. One thousand cycles of motion after all 3 ligaments were sectioned caused additional kinematic changes in the scaphoid and lunate. The scapholunate ligament appears to be the primary stabilizer between the scaphoid and lunate. The radioscaphocapitate and scaphotrapezial ligaments are secondary restraints. Repetitive cyclic motion after ligament sectioning appears to have additional deleterious effects on carpal kinematics. PMID:12457349

  3. Technical evaluation report on the proposed design modifications and technical specification changes on grid voltage degradation for the Millstone Nuclear Power Station, Unit 1

    SciTech Connect

    Selan, J.C.

    1982-05-13

    This report documents the technical evaluation of the proposed design modifications and Technical Specification change for protection of Class 1E equipment from grid voltage degradation for the Millstone Nuclear Power Station, Unit 1. The review criteria are based on several IEEE standards and the Code of Federal Regulations. The evaluation finds that the licensee has not provided sufficient information on the undervoltage protection system to allow a complete evaluation into the adequacy of protecting the Class 1E equipment from sustained voltage degradation.

  4. Evaluation of modulating field of photoreflectance of surface-intrinsic-n+ type doped GaAs by using photoinduced voltage

    NASA Astrophysics Data System (ADS)

    Lee, W. Y.; Chien, J. Y.; Wang, D. P.; Huang, K. F.; Huang, T. C.

    2002-04-01

    Photoreflectance (PR) of surface-intrinsic-n+ type doped GaAs has been measured for various power densities of pump laser. The spectra exhibited many Franz-Keldysh oscillations, whereby the strength of electric field F in the undoped layer can be determined. The thus obtained Fs are subject to photovoltaic effect and are less than built-in field Fbi. In the previous work we have obtained the relation F?Fbi-?F/2 when ?F?Fbi by using electroreflectance to simulate PR, where ?F is the modulating field of the pump beam. In this work a method was devised to evaluate ?F by using photoinduced voltages Vs and, hence, the relation can be verified by PR itself. The ?Fs obtained by Vs are also consistent with those of using imaginary part of fast Fourier transform of PR spectra.

  5. Evaluation of accelerated stability test conditions for medicated chewing gums.

    PubMed

    Maggi, Lauretta; Conte, Ubaldo; Nhamias, Alain; Grenier, Pascal; Vergnault, Guy

    2013-10-01

    The overall stability of medicated chewing gums is investigated under different storage conditions. Active substances with different chemical stabilities in solid state are chosen as model drugs. The dosage form is a three layer tablet obtained by direct compression. The gum core contains the active ingredient while the external layers are formulated to prevent gum adhesion to the punches of the tableting machine. Two accelerated test conditions (40°C/75% RH and 30°C/65% RH) are performed for 6 months. Furthermore, a long-term stability test at room conditions is conducted to verify the predictability of the results obtained from the stress tests. Some drugs are stable in all the conditions tested, but other drugs, generally considered stable in solid dosage forms, have shown relevant stability problems particularly when stress test conditions are applied to this particular semi-solid dosage forms. For less stable drugs, the stress conditions of 40°C/75% RH are not always predictable of chewing gum stability at room temperature and may produce false negative; intermediate conditions, 30°C/65% RH, are more predictive for this purpose, the results of drug content found after 6 months at intermediate stress conditions and 12 months at room conditions are generally comparable. But the results obtained show that only long-term conditions stability tests gave consistent results. During aging, the semi solid nature of the gum base itself, may also influence the drug delivery rate during chewing and great attention should be given also to the dissolution stability. PMID:22794248

  6. Design and evaluation of single nozzle with a non-conductive tip for reducing applied voltage and pattern width in electrohydrodynamic jet printing (EHDP)

    Microsoft Academic Search

    Sang-Yoon Kim; Yong Kim; Jaehong Park; Jungho Hwang

    2010-01-01

    We investigated the effect of a non-conductive tip inserted into a capillary nozzle (inner diameter of 860 µm) on jet formation and pattern width in electrohydrodynamic jet printing. Simulated and experimental results showed that the non-conductive tip stabilized the jet, and reduced the effective nozzle diameter and the onset voltage needed for the cone-jet mode, by eliminating the backflow near

  7. A study of dynamic aspects related to voltage collapse in power systems

    Microsoft Academic Search

    V. Ajjarapu

    1989-01-01

    The applicability of the multiparameter stability theory proposed in a book by K. Huseyin (1975) to the study of voltage stability in power systems is explored. The methodology is based on the eigenvalues of the Jacobian matrix, evaluated at an arbitrary equilibrium point in the vicinity of a singular point (or critical point), and an asymptotic equation of the equilibrium

  8. Technical evaluation report on the adequacy of station electric distribution system voltages for the Peach Bottom Atomic Power Station. Units 2 and 3

    SciTech Connect

    White, R.L.

    1982-06-21

    This report documents the technical evaluation of the adequacy of the station electric distribution system voltages for the Peach Bottom Atomic Power Station, Units 2 and 3. The evaluation is to determine if the onsite distribution system, in conjunction with the offsite power sources, has sufficient capacity to automatically start and operate all Class 1E loads within the equipment voltage ratings under certain conditions established by the Nuclear Regulatory Commission. The analysis submitted indicates that the capacity is sufficient to meet the NRC requirements provided specific plant procedures are followed for shutting down the second unit after an accident in the first unit and with a loss of one offsite source.

  9. Evaluation of Condor SS as a soil stabilizer 

    E-print Network

    Ahmed, Shamim

    1995-01-01

    manufacturing and coal burning lead to the production of various pozzolans such as lime kiln dust and Class C fly-ash. Reactions between pozzolanic stabilizers and soil include cation exchange, flocculation and agglomeration. Silica and alumina provided... Seal) are the other major types of non-standard stabilizers. A mineral pitch is an organic material that is soluble in organic solvents but not in water. It is contained by an emulsifying agent in a water emulsion with 40 percent solids and performs...

  10. Development and flight evaluation of an augmented stability active controls concept with a small tail

    NASA Technical Reports Server (NTRS)

    1980-01-01

    Parasite drag reduction evaluation is composed of wind tunnel tests with a standard L-1011 tail and two reduced area tail configurations. Trim drag reduction is evaluated by rebalancing the airplane for relaxed static stability. This is accomplished by pumping water to tanks in the forward and aft of the airplane to acheive desired center of gravity location. Also, the L-1011 is modified to incorporate term and advanced augmented systems. By using advanced wings and aircraft relaxed static stability significant fuel savings can be realized. An airplane's dynamic stability becomes more sensitive for decreased tail size, relaxed static stability, and advanced wing configurations. Active control pitch augmentation will be used to acheive the required handling qualities. Flight tests will be performed to evaluate the pitch augmentation systems. The effect of elevator downrig on stabilizer/elevator hinge moments will be measured. For control system analysis, the normal acceleration feedback and pitch rate feedback are analyzed.

  11. Archaerhodopsin Voltage Imaging: Synaptic Calcium and BK Channels Stabilize Action Potential Repolarization at the Drosophila Neuromuscular Junction

    PubMed Central

    Ford, Kevin J.

    2014-01-01

    The strength and dynamics of synaptic transmission are determined, in part, by the presynaptic action potential (AP) waveform at the nerve terminal. The ion channels that shape the synaptic AP waveform remain essentially unknown for all but a few large synapses amenable to electrophysiological interrogation. The Drosophila neuromuscular junction (NMJ) is a powerful system for studying synaptic biology, but it is not amenable to presynaptic electrophysiology. Here, we demonstrate that Archaerhodopsin can be used to quantitatively image AP waveforms at the Drosophila NMJ without disrupting baseline synaptic transmission or neuromuscular development. It is established that Shaker mutations cause a dramatic increase in neurotransmitter release, suggesting that Shaker is predominantly responsible for AP repolarization. Here we demonstrate that this effect is caused by a concomitant loss of both Shaker and slowpoke (slo) channel activity because of the low extracellular calcium concentrations (0.2–0.5 mm) used typically to assess synaptic transmission in Shaker. In contrast, at physiological extracellular calcium (1.5 mm), the role of Shaker during AP repolarization is limited. We then provide evidence that calcium influx through synaptic CaV2.1 channels and subsequent recruitment of Slo channel activity is important, in concert with Shaker, to ensure proper AP repolarization. Finally, we show that Slo assumes a dominant repolarizing role during repetitive nerve stimulation. During repetitive stimulation, Slo effectively compensates for Shaker channel inactivation, stabilizing AP repolarization and limiting neurotransmitter release. Thus, we have defined an essential role for Slo channels during synaptic AP repolarization and have revised our understanding of Shaker channels at this model synapse. PMID:25355206

  12. GMAW process stability evaluation through acoustic emission by time and frequency domain analysis

    Microsoft Academic Search

    E. Huanca Cayo; S. C. Absi Alfaro

    2009-01-01

    Purpose: In the present work was made the comparative analysis in time domain and frequency domain to the acoustical pressure generate by the electric arc to determinate which of the two analysis methods is better to evaluates the stability in GMAW process. Design\\/methodology\\/approach: Welds had been made with the parameters adjusted to get the highest stability. In these conditions, were

  13. EVALUATION OF CHEMICALLY BONDED PHOSPHATE CERAMICS FOR MERCURY STABILIZATION OF A MIXED SYNTHETIC WASTE

    EPA Science Inventory

    This experimental study was conducted to evaluate the stabilization and encapsulation technique developed by Argonne National Laboratory, called the Chemically Bonded Phosphate Ceramics technology for Hg- and HgCl2-contaminated synthetic waste materials. Leachability ...

  14. EVALUATION USING AN ORGANOPHILIC CLAY TO CHEMICALLY STABILIZE WASTE CONTAINING ORGANIC COMPOUNDS

    EPA Science Inventory

    A modified clay (organophilic) was utilized to evaluate the potential for chemically stabilizing a waste containing organic compounds. hemical bonding between the binder and the contaminants was indicated. eachate testing also indicated strong binding. Copy available at NTIS as ...

  15. Comprehensive Stability Evaluation of Rock Slope Using the Cloud Model-Based Approach

    NASA Astrophysics Data System (ADS)

    Liu, Zaobao; Shao, Jianfu; Xu, Weiya; Xu, Fei

    2014-11-01

    This article presents the cloud model-based approach for comprehensive stability evaluation of complicated rock slopes of hydroelectric stations in mountainous area. This approach is based on membership cloud models which can account for randomness and fuzziness in slope stability evaluation. The slope stability is affected by various factors and each of which is ranked into five grades. The ranking factors are sorted into four categories. The ranking system of slope stability is introduced and then the membership cloud models are applied to analyze each ranking factor for generating cloud memberships. Afterwards, the obtained cloud memberships are synthesized with the factor weights given by experts for comprehensive stability evaluation of rock slopes. The proposed approach is used for the stability evaluation of the left abutment slope in Jinping 1 Hydropower Station. It is shown that the cloud model-based strategy can well consider the effects of each ranking factor and therefore is feasible and reliable for comprehensive stability evaluation of rock slopes.

  16. Tris(trimethylsilyl)borate as an electrolyte additive for improving interfacial stability of high voltage layered lithium-rich oxide cathode/carbonate-based electrolyte

    NASA Astrophysics Data System (ADS)

    Li, Jianhui; Xing, Lidan; Zhang, Ruiqin; Chen, Min; Wang, Zaisheng; Xu, Mengqing; Li, Weishan

    2015-07-01

    Tris(trimethylsilyl)borate (TMSB) is used as an electrolyte additive for high voltage lithium-rich oxide cathode of lithium ion battery. The interfacial natures of Li[Li0.2Mn0.54Ni0.13Co0.13]O2/carbonate-based electrolyte are investigated with a combination of electrochemical measurements and physical characterizations. Charge/discharge tests show that the cyclic performance of Li[Li0.2Mn0.54Ni0.13Co0.13]O2 in a mixed carbonate electrolyte is significantly improved by using TMSB. After 200 cycles between 2 V and 4.8 V (vs. Li/Li+) at 0.5 C rate, the capacity retention of Li[Li0.2Mn0.54Ni0.13Co0.13]O2 is only 19% in the blank electrolyte, while it is improved to 74% when 0.5% TMSB is applied. The results from physical characterizations demonstrate that this excellent cyclic performance is attributed to the improved interfacial stability of Li[Li0.2Mn0.54Ni0.13Co0.13]O2/electrolyte due to the thin and protective film generated by TMSB.

  17. Evaluation of lime-fly ash stabilized bases and subgrades using static and dynamic deflection systems

    E-print Network

    Raba, Gary W.

    1982-01-01

    EVALUATION OF LIME-FLY ASH STABILIZED BASFS AND SUBGRADES USING STATIC AND DYNAMIC DEFLECTION SYSTEMS A Thesis GARY W. RABA Submitted to the Graduate College of Texas AIIM University in partial fulfillment of the requirements for the degree... of MASTER OF SCIENCE December 1982 Major Subject: Civil Engineering EVALUATION OF LIME-FLY ASH STABILIZED BASES AND SUBGRADES USING STATIC AND DYNAMIC DEFLECTION SYSTEMS A Thesis by Gary Nl. Raba Approved as to style and content by: !Chairman...

  18. Longitudinal Measurement Models in Evaluation Research: Examining Stability and Change.

    ERIC Educational Resources Information Center

    Pitts, Steven C.; And Others

    1996-01-01

    An introduction is provided to the use of confirmatory factor analysis to test measurement invariance and stability in longitudinal research. The approach is illustrated through examples representing one or two constructs in one to three measurement waves. Basic issues in establishing measurement invariance are discussed. (SLD)

  19. Voltage Drop

    NSDL National Science Digital Library

    The first site with information on voltage drop is provided by Power and System Innovations on their Frequently Asked Questions: Voltage Drop (1) page. Visitors can read what voltage drop is, what causes it, what happens as a result of it, and what the maximum recommended voltage drop is. The second site, Basics of Electricity (2), is part of General Electric's Lighting for Business Web site. Through descriptions and illustrations, the site explains what voltage drop is and gives examples of how it is calculated using Ohm's law. The next site is a lab worksheet that is part of a class from the Electrical and Computer Engineering Department of Montana State University called Voltage Drop in Cables (3). The objective of the lesson is to determine the internal resistance of an extension cord and choose the proper wire size for a particular application. Students are given an explanation of the procedure and a number of questions to answer related to the exercise. The Oregon Building Congress offers the Lesson Plans (4) Web site and the downloadable Voltage Drop educational activity. The lesson, which is suggested to be contained within a unit on formulas and solving literal equations, explores the concept of voltage drop that is encountered in basic wiring. The fifth site entitled Explanation of Voltage Drop in a Series Circuit (5) is offered by the Horizons Electronic Lesson Plan Resource. The page describes voltage drop as an electronic concept, gives a formula determining voltage drop, provides a schematic that helps illustrate the concept, and offers a quiz and answer sheet. Next, from electrician.com, is the online Voltage Drop Calculator (6). Users input the type and size of wire being used, the voltage and phase, circuit length, and amp load to calculate voltage drop and several other parameters. The seventh site, entitled The Hazards of Voltage Drop (7), is provided within the Electrical Construction Maintenance Web site. The page describes how electrical equipment can overheat or even power down if it operates below its voltage rating. It also provides a thorough explanation of how to determine the load's operating voltage. The last site, maintained by Williamson Labs (8), is a comprehensive learning site called Elementary Electricity. Visitors will find a wealth of information here, including fun descriptions, graphics, and animations on all aspects of electricity including voltage drop.

  20. Comparison of the -1/? Locus Method with Classical Method for Evaluation of the Stability Margin of Multiloop Flight Control Systems

    NASA Astrophysics Data System (ADS)

    Katayanagi, Ryoji

    A method to exactly evaluate the stability margin for multiloop control systems has not been established yet. In this paper, it is shown that the results of the classical method of stability margin which is used by designers of aircraft manufacturers is conservative. Previous research has proposed the “-1/? locus” analysis method for the evaluation of the stability margin. Using this -1/? locus method, more exact evaluation of the stability margin of multiloop flight control systems is presented.

  1. Technical evaluation of the proposed design modifications and technical specification changes on grid voltage degradation (Part A) for the Pilgrim Nuclear Power Station, Unit 1

    SciTech Connect

    White, R.L.

    1980-01-01

    This report documents the technical evaluation of the proposed design modifications and Technical Specification changes for protection of Class 1E equipment from grid voltage degradation for the Pilgrim Nuclear Power Station. The review criteria are based on several IEEE standards and the Code of Federal Regulations. The evaluation compares the submittals made by the licensee with the NRC staff positions and the review criteria and presents the reviewer's conclusion on the acceptability of the proposed system.

  2. Piloted simulator evaluation of a relaxed static stability fighter at high angle-of-attack

    NASA Technical Reports Server (NTRS)

    Lapins, M.; Klein, R. W.; Martorella, R. P.; Cangelosi, J.; Neely, W. R., Jr.

    1982-01-01

    A piloted simulator evaluation of the stability and control characteristics of a relaxed static stability fighter aircraft was conducted using a differential maneuvering simulator. The primary purpose of the simulation was to evaluate the effectiveness of the limiters in preventing departure from controlled flight. The simulation was conducted in two phases, the first consisting of open-loop point stability evaluations over a range of subsonic flight conditions, the second concentrating on closed-loop tracking of a preprogrammed target in low speed, high angle-of-attack air combat maneuvering. The command limiters were effective in preventing departure from controlled flight while permitting competent levels of sustained maneuvering. Parametric variations during the study included the effects of pitch control power and wing-body static margin. Stability and control issues were clearly shown to impact the configuration design.

  3. Evaluation of degradation kinetics and physicochemical stability of tenofovir

    PubMed Central

    Agrahari, Vivek; Putty, Sandeep; Mathes, Christiane; Murowchick, James B.; Youan, Bi-Botti C.

    2014-01-01

    Tenofovir (TFV) has been proven to prevent the transmission of the Human Immunodeficiency Virus (HIV) through the vagina. But, there is little information available about its stability under various storage and stress conditions. Hence, this study aimed to investigate the degradation behavior and physicochemical stability of TFV using liquid chromatography coupled mass spectrometry (LC-MS) and solid state X-ray diffraction (XRD) analyses. The LC-MS analysis was performed on a QTrap mass spectrometer with an enhanced mass spectrum (EMS) scan in positive mode. A reversed phase C18 column was used as the stationary phase. TFV exhibited degradation under acidic and alkaline hydrolytic conditions. The degradation products with m/z 289.2 and 170 amu have been proposed as 6-Hydroxy adenine derivative of TFV, and (2-hydroxypropan-2-yloxy) methylphosphonic acid, respectively. A pseudo-first-order degradation kinetic allowed for estimating the shelf-life, half-life, and time required for 90% degradation values of 3.84,25.34, and 84.22 h in acidic conditions, and 58.26,384.49, and 1277.75 h in alkaline conditions, respectively. No significant degradation was observed at pH 4.5 (normal cervicovaginal pH) and oxidative stress conditions of 3% and 30% v/v hydrogen peroxide solution. The shelf life of TFV powder at room temperature was 23 months as calculated by using an Arrhenius plot. The XRD pattern showed that the drug was stable and maintained its original crystallinity under the accelerated and thermal stress conditions applied. Stability analyses revealed that the TFV was stable in various stress conditions; however, formulation strategies should be implemented to protect it in strong acidic and alkaline environments. PMID:24817173

  4. Bench-Scale Evaluation Of Chemically Bonded Phosphate Ceramic Technology To Stabilize Mercury Waste Mixtures

    EPA Science Inventory

    This bench-scale study was conducted to evaluate the stabilization of mercury (Hg) and mercuric chloride-containing surrogate test materials by the chemically bonded phosphate ceramics technology. This study was performed as part of a U.S. EPA program to evaluate treatment and d...

  5. Non-iterative Voltage Stability

    SciTech Connect

    Makarov, Yuri V.; Vyakaranam, Bharat; Hou, Zhangshuan; Wu, Di; Meng, Da; Wang, Shaobu; Elbert, Stephen T.; Miller, Laurie E.; Huang, Zhenyu

    2014-09-30

    This report demonstrates promising capabilities and performance characteristics of the proposed method using several power systems models. The new method will help to develop a new generation of highly efficient tools suitable for real-time parallel implementation. The ultimate benefit obtained will be early detection of system instability and prevention of system blackouts in real time.

  6. RESULTS FROM THE STABILIZATION TECHNOLOGIES EVALUATED BY THE SITE PROGRAM

    EPA Science Inventory

    The Superfund Innovative Technology Evaluation (SITE) Program was developed to assist the development of hazardous waste treatment technologies necessary to implement new cleanup standards which require greater reliance on permanent remedies. s part of the SITE program, four stab...

  7. A critical evaluation of whole cell patch clamp studies on electroporation using the voltage sensitive dye ANNINE-6.

    PubMed

    Wegner, Lars H; Frey, Wolfgang; Schönwälder, Sina

    2013-08-01

    The patch clamp technique in the whole cell configuration is potentially a powerful tool to investigate electroporation (electric-field-induced membrane permeabilization). Membrane polarization beyond certain threshold voltages leads to a steep conductance increase either indicating field-induced pore formation or being due to patch clamp artifacts (seal resistance breakdown). Protoplasts derived from tobacco culture cell lines (Bright Yellow-2, BY-2; Virginia bright Italian-0, VBI-0) were stained with the voltage-sensitive dye ANNINE-6. After establishing the whole cell patch clamp configuration 50-ms command voltage (Ucomm) steps ranging from -500 mV to +500 mV were applied while simultaneously exposing protoplasts to light at 475 nm wavelength. Pulse-induced currents and fluorescence intensity (known to be linearly related to the trans-membrane voltage, Um) were recorded. Plotting fluorescence intensity against Ucomm revealed saturation of the curve at values<-300 mV and >+300 mV and close correlation with theoretical Um values calculated on the basis of membrane pore formation. For BY-2 and VBI-0 protoplasts ANNINE-6 voltage sensitivity was calculated to be -0.0014 mV(-1) and -0.0012 mV(-1), respectively. Voltage ramp experiments revealed cation-selectivity of field-induced pores. Anions are conducted poorly independent of their size. In conclusion, the patch clamp technique is validated as a useful tool in electroporation research. PMID:23603150

  8. Optimal power flow incorporating voltage collapse constraints

    Microsoft Academic Search

    William Rosehart; C. Canizares; Victor Quintana

    1999-01-01

    The paper presents applications of optimization techniques to voltage collapse studies. First a “maximum distance to voltage collapse” algorithm that incorporates constraints on the current operating conditions is presented. Second, an optimal power flow formulation that incorporates voltage-stability criteria is proposed. The algorithms are tested on a 30-bus system using a standard power flow model, where the effect of limits

  9. Voltage Controlled Voltage Source (VCVS)

    NSDL National Science Digital Library

    Dorf, Richard C.

    Hosted by Clarkson University, this applet demonstrates a circuit that contains a voltage controlled voltage source (VCVS). The gain may be modified using the scroll bar. Even though brief, this resource can be used in a variety of different technical education classrooms.

  10. Evaluation of delay-time degradation of low-voltage BiCMOS based on a novel analytical delay-time modeling

    Microsoft Academic Search

    Minoru Fujishima; Kunihiro Asada; Takuo Sugano

    1991-01-01

    The degradation of delay time of totem-pole BiCMOS, CBiCMOS, and BiNMOS circuits by supply voltage reduction is evaluated by a novel delay-time model. It has been found that base-collector capacitance plays a greater role in determining the delay time than other parasitic capacitances in BiCMOS circuits. It is concluded that when the input signal swings fully from zero to the

  11. Saunders M., Charlier B., Bonamy J., 2005," Using evaluation to create `provisional stabilities': bridging innovation in Higher Education change processes", Evaluation, Sage Publications London,

    E-print Network

    Paris-Sud XI, Université de

    Saunders M., Charlier B., Bonamy J., 2005," Using evaluation to create `provisional stabilities __________________________________________________________________________________________ Murray Saunders, Bernadette Charlier and Joel Bonamy Contact: m.saunders@lancaster.ac.uk Abstract

  12. Label stability in serum of four radionuclides on DTPA-coupled antibodies--an evaluation.

    PubMed

    Hnatowich, D J

    1986-01-01

    Although DTPA forms strong chelates with many metals, the harsh chemical environment of the serum may nevertheless dissociate metallic radionuclides from DTPA attached to proteins. We have investigated the stability in 37 degrees C serum of 111In, 99mTc, 90Y and 153Gd chelated to DTPA-coupled antibodies. Stability was evaluated primarily by affinity chromatography and HPLC analysis of serum incubates; however, the stability of 111In was determined in vivo in patient studies. Analysis of patient urine showed no evidence for dissociation of DTPA from antibody whereas analysis of serum demonstrated exchange rates of 111In to transferrin of about 9%/day. When labeled by the described method, 99mTc on DTPA coupled antibodies shows instability in serum but superior stability than 99mTc on antibodies without the attached DTPA. Both 90Y and 153Gd dissociate in serum at rates which are comparable to that of 111In. PMID:3793489

  13. Technical-evaluation report on the adequacy of station electric-distribution-system voltages for the Prairie Island Nuclear Generating Plant, Units 1 and 2. (Docket Nos. 50-282, 50-306)

    SciTech Connect

    Selan, J C

    1982-09-17

    This report documents the technical evaluation of the adequacy of the station electric distribution system voltages for the Prairie Island Nuclear Generating Plant, Units 1 and 2. The evaluation is to determine if the onsite distribution system in conjunction with the offsite power sources has sufficient capacity to automatically start and operate all Class 1E loads within the equipment voltage ratings under certain conditions established by the Nuclear Regulatory Commission. The evaluation finds that with some minor transformer loading modifications, hardware changes and the results of equipment testing and manufacturer data, the offsite sources were demonstrated to supply adequate voltage to the Class 1E equipment under worst case conditions.

  14. Operating stability of a self-breakdown spark-gap frequency switch rated at a voltage of 300 kV and a switched power of up to 450 J

    NASA Astrophysics Data System (ADS)

    Koval'chuk, B. M.; Korolev, Yu. D.; Kumpyak, E. V.; Frants, O. B.; Shemyakin, I. A.

    2014-12-01

    A test bench for studying two-electrode spark gaps rated at a voltage of 300 kV and a pulse repetition rate of up to 10 Hz and operating in air at elevated pressure. The typical time of pulse charging of a capacitive storage in the bench equals about 100 ?s. The object of investigation is a spark gap the operating stability of which at a level of 10% of the rate voltage is achieved by initiating a corona discharge at the prebreakdown stage. It is shown that unstable operation is due to the accumulation of nitrogen oxides in the gap. To maintain the oxide content at an acceptable level, continuous gas purging is applied and necessary gas flow rates are estimated.

  15. The trajectory based network transient energy evaluation and its application to enhancement of transient stability

    Microsoft Academic Search

    Cai Guowei; Mu Gang; Liu Zhuo; Lin Zizhao

    1998-01-01

    This paper proposes a method to calculate the transient energy in electrical power networks on the basis of the topological energy function. For a given unstable mode, a novel technique to evaluate cutsets that critically affect the transient stability of the power system is developed according to the change of first swing transient energy of cutsets during the post-fault period.

  16. Using Standalone GPS to Evaluate Precise Oscillator Stability in the Time Domain

    E-print Network

    Calgary, University of

    Using Standalone GPS to Evaluate Precise Oscillator Stability in the Time Domain M.G. Petovello and hydrography. He has been involved with GPS developments and applications since 1980 and is the author of many. However, a relatively inexpensive GPS receiver is capable of exploiting the highly stable GPS time scale

  17. EVALUATION OF THE THERMAL STABILITY POHC INCINERABILITY RANKING IN A PILOT-SCALE ROTARY KILN INCINERATOR

    EPA Science Inventory

    A series of pilot-scale incineration tests was performed at EPA's Incineration Research Facility to evaluate the thermal stability-based POHC incinerability ranking. In the tests, mixtures of 12 P0HCs with predicted incinerability spanning the range af most to least difficult to ...

  18. UNITED STATES ENVIRONMENTAL PROTECTION AGENCY MUNICIPAL WASTE COMBUSTION RESIDUE SOLIDIFICATION/STABILIZATION EVALUATION PROGRAM

    EPA Science Inventory

    Vendors of solidification/stabilization (S/S) and other technologies are cooperating with the U.S. Environmental Protection Agency's (U.S. EPA's) Office of Research and Development (ORD), Risk Reduction Engineering Laboratory to demonstrate and evaluate the performance of the tec...

  19. Evaluation of nitrogen reduction in water hyacinth ponds integrated with waste stabilization ponds

    Microsoft Academic Search

    Qitao Yi; Youngchul Kim; Masafumi Tateda

    2009-01-01

    In this paper, a combined aquatic treatment process coupling waste stabilization ponds (WSPs) with water hyacinth ponds (WHPs) was investigated as means to upgrade secondary effluent from a waste water treatment plant (WWTP). Naturally-occurring nitrification and denitrification phenomena were monitored and evaluated on a quantitative basis. The WSP supplied oxygen to the post process WHP, while the inside of the

  20. TECHNOLOGY EVALUATION REPORT: SILICATE TECHNOLOGY CORPORATION, SOLIDIFICATION/STABILIZATION OF PCP AND INORGANIC CONTAMINANTS IN SOILS SELMA, CA

    EPA Science Inventory

    A Superfund Innovative Technology Evaluation demonstration was conducted to evaluate the ability of the solidification/ stabilization treatment process developed by Silicate Technology Corporation (STC) to reduce the mobility and leaching potential of organic and inorganic contam...

  1. Evaluation of Hose in Hose Transfer Line Service Life for Hanford's Interim Stabilization Program

    SciTech Connect

    TORRES, T.D.

    2000-08-24

    RPP-6153, Engineering Task Plan for Hose-in-Hose Transfer System for the Interim Stabilization Program, defines the programmatic goals, functional requirements, and technical criteria for the development and subsequent installation of transfer line equipment to support Hanford's Interim Stabilization Program. RPP-6028, Specification for Hose in Hose Transfer Lines for Hanford's Interim Stabilization Program, has been issued to define the specific requirements for the design, manufacture, and verification of transfer line assemblies for specific waste transfer applications. Included in RPP-6028 are tables defining the chemical constituents of concern to which transfer lines will be exposed. Current Interim Stabilization Program planning forecasts that the at-grade transfer lines will be required to convey pumpable waste for as much as three years after commissioning. Prudent engineering dictates that the equipment placed in service have a working life in excess of this forecasted time period, with some margin to allow for future adjustments to the planned schedule. This document evaluates the effective service life of the Hose-in-Hose Transfer Lines, based on information submitted by the manufacturer and published literature. The effective service life of transfer line assemblies is a function of several factors. Foremost among these are process fluid characteristics, ambient environmental conditions, and the manufacturer's stated shelf life. This evaluation examines the manufacturer's certification of shelf life, the manufacturer's certifications of chemical compatibility with waste, and published literature on the effects of exposure to ionizing radiation on the mechanical properties of elastomeric materials to evaluate transfer line service life.

  2. Evaluation of Long Term Stability of Model Emulsions by Multisample Analytical Centrifugation

    Microsoft Academic Search

    G. G. Badolato; F. Aguilar; H. P. Schuchmann; T. Sobisch; D. Lerche

    Emulsion-based products are found within the chemical and agrochemical, cosmetic, pharmaceutical,\\u000a and food industries. As emulsion structures are thermodynamically unstable, shelf-life stability is a main\\u000a aspect in product and process development. The objective of this work was to evaluate multisample analytical\\u000a centrifugation with STEP-technology as an accelerated test for predicting the long-term stability of emulsions.\\u000a Therefore, model emulsions were designed that

  3. Evaluating the accuracy of current-voltage characteristics approximations in the nondiffusion theory of space-charge-limited currents

    Microsoft Academic Search

    A. N. Ziuganov

    1975-01-01

    The accuracy of the theory of space-charge-limited currents for quasi-monopolar semiconductors with an arbitrary structure of the forbidden-band local states is discussed. Computer-aided calculations of the current-voltage (IV) characteristics for band schemes of weak and strong population are used to determine the accuracy of the corresponding approximations of the IV characteristic for an arbitrary band scheme of a semiconductor with

  4. Assessment of stability effects of HVDC link by an improved energy function method

    Microsoft Academic Search

    T. S. Chung

    1999-01-01

    This paper proposes new techniques for the fast transient stability analysis of power systems embedded with HVDC (high voltage DC link) based on a corrected transient energy function approach. The method is based on an innovative iteration approach used to evaluate the AC terminal voltages of HVDC links at each integration step and is developed for enhancing the efficiency of

  5. Technical evaluation of the adequacy of station electric distribution system voltages for the R. E. Ginna Nuclear Power Station, Unit 1: selected issues program (Docket No. 50-244)

    SciTech Connect

    Selan, J. C.

    1981-11-05

    This report documents the technical evaluation of the adequacy of the station electric distribution system voltages for the R.E. Ginna Nuclear Power Station, Unit 1. The evaluation is to determine if the onsite distribution system, in conjunction with the offsite power sources, has sufficient capacity to automatically start and operate all Class 1E loads within the equipment voltage ratings under certain conditions established by the Nuclear Regulatory Commission. The analysis submitted demonstrates that acceptable voltages will be supplied to the Class 1E equipment under worst case conditions.

  6. Technical evaluation of the adequacy of station electric distribution systems voltages for the Calvert Cliffs Nuclear Power Plant, Units 1 and 2. Docket Nos. 50-317, 50-318

    SciTech Connect

    Selan, J. C.

    1982-04-09

    This report documents the technical evaluation of the adequacy of the station electric distribution system voltages for the Calvert Cliffs Nuclear Power Plant, Units 1 and 2. The evaluation is to determine if the onsite distribution system in conjunction with the offsite power sources has sufficient capacity to automatically start and operate all Class 1E loads within the equipment voltage ratings under certain conditions established by the Nuclear Regulatory Commission. The analyses submitted demonstrate that adequate voltage will be supplied to the Class 1E equipment under worst case conditions.

  7. SOCIAL STABILITY AND HIV RISK BEHAVIOR: EVALUATING THE ROLE OF ACCUMULATED VULNERABILITY

    PubMed Central

    German, Danielle; Latkin, Carl A.

    2011-01-01

    This study evaluated a cumulative and syndromic relationship among commonly co-occurring vulnerabilites (homelessness, incarceration, low-income, residential transition) in association with HIV-related risk behaviors among 635 low-income women in Baltimore. Analysis included descriptive statistics, logistic regression, latent class analysis and latent class regression. Both methods of assessing multidimensional instability showed significant associations with risk indicators. Risk of multiple partners, sex exchange, and drug use decreased significantly with each additional domain. Higher stability class membership (77%) was associated with decreased likelihood of multiple partners, exchange partners, recent drug use, and recent STI. Multidimensional social vulnerabilities were cumulatively and synergistically linked to HIV risk behavior. Independent instability measures may miss important contextual determinants of risk. Social stability offers a useful framework to understand the synergy of social vulnerabilities that shape sexual risk behavior. Social policies and programs aiming to enhance housing and overall social stability are likely to be beneficial for HIV prevention. PMID:21259043

  8. Macrocyclic biphenyl tetraoxazoles: Synthesis, evaluation as G-quadruplex stabilizers and cytotoxic activity

    PubMed Central

    Blankson, Gifty A.; Pilch, Daniel S.; Liu, Angela A.; Liu, Leroy F.; Rice, Joseph E.; LaVoie, Edmond J.

    2014-01-01

    A series of macrocyclic biphenyl tetraoxazoles was synthesized. The latter stages of the synthetic approach allowed for the addition of varied N-protected ?-amino acids, which were subsequently deprotected and condensed to provide the desired macrocycles. Improved yields could be realized in the macrocyclization step of their synthesis relative to other macrocyclic G-quadruplex stabilizers. These 24-membered macrocycles were evaluated for their ability to stabilize G-quadruplex DNA and for their relative cytotoxicity against human tumor cells. These biphenyl tetraoxazoles were not strong ligands for G-quadruplex DNA relative to other macrocyclic polyoxazoles. This reduced stabilizing potential did correlate with their comparatively lower cytotoxic activity as observed in the human tumor cell lines, RPMI 8402 and KB3-1. These studies provide useful insights into the conformational requirements for the development of selective and more potent G-quadruplex ligands. PMID:23787291

  9. Evaluation of iodine content and stability in recipes prepared with biofortified potatoes.

    PubMed

    Cerretani, Lorenzo; Comandini, Patrizia; Fumanelli, Davide; Scazzina, Francesca; Chiavaro, Emma

    2014-11-01

    Iodine is an essential micronutrient of the human diet. Deficiency of iodine is diffused in many areas of the world and mild deficiency is present also in developed countries around Europe. Biofortification of vegetables could represent a better strategy with respect to iodized salt in order to increase iodine intake. The aim of this study was evaluating the stability of iodine, derived from biofortified potatoes, in the preparation process of three Italian typical dishes: dumplings, vegetable pie, and focaccia bread. The obtained results showed a good stability of iodine in cooking processes, in particular, during baking of focaccia bread. Significant losses of iodine were detected during boiling of dumplings and baking of vegetable pie. Although the different stability during the cooking processes, the three dishes maintained a good final content of iodine, ranging from the 33.3% to 52.7% of daily recommended intake in adults for individual serving size. PMID:24828007

  10. Flight evaluation of the transonic stability and control characteristics of an airplane incorporating a supercritical wing

    NASA Technical Reports Server (NTRS)

    Matheny, N. W.; Gatlin, D. H.

    1978-01-01

    A TF-8A airplane was equipped with a transport type supercritical wing and fuselage fairings to evaluate predicted performance improvements for cruise at transonic speeds. A comparison of aerodynamic derivatives extracted from flight and wind tunnel data showed that static longitudinal stability, effective dihedral, and aileron effectiveness, were higher than predicted. The static directional stability derivative was slower than predicted. The airplane's handling qualities were acceptable with the stability augmentation system on. The unaugmented airplane exhibited some adverse lateral directional characteristics that involved low Dutch roll damping and low roll control power at high angles of attack and roll control power that was greater than satisfactory for transport aircraft at cruise conditions. Longitudinally, the aircraft exhibited a mild pitchup tendency. Leading edge vortex generators delayed the onset of flow separation, moving the pitchup point to a higher lift coefficient and reducing its severity.

  11. Evaluation of the Stability of Concentrated Emulsions for Lemon Beverages Using Sequential Experimental Designs

    PubMed Central

    Almeida, Teresa Cristina Abreu; Larentis, Ariane Leites; Ferraz, Helen Conceição

    2015-01-01

    The study of the stability of concentrated oil-in-water emulsions is imperative to provide a scientific approach for an important problem in the beverage industry, contributing to abolish the empiricism still present nowadays. The use of these emulsions would directly imply a reduction of transportation costs between production and the sales points, where dilution takes place. The goal of this research was to evaluate the influence of the main components of a lemon emulsion on its stability, aiming to maximize the concentration of oil in the beverage and to correlate its physicochemical characteristics to product stability, allowing an increase of shelf life of the final product. For this purpose, analyses of surface and interface tension, electrokinetic potential, particle size and rheological properties of the emulsions were conducted. A 24-1 fractional factorial design was performed with the following variables: lemon oil/water ratio (30% to 50%), starch and Arabic gum concentrations (0% to 30%) and dioctyl sodium sulfosuccinate (0 mg/L to 100 mg/L), including an evaluation of the responses at the central conditions of each variable. Sequentially, a full design was prepared to evaluate the two most influential variables obtained in the first plan, in which concentration of starch and gum ranged from 0% to 20%, while concentration of lemon oil/water ratio was fixed at 50%, without dioctyl sodium sulfosuccinate. Concentrated emulsions with stability superior to 15 days were obtained with either starch or Arabic gum and 50% lemon oil. The most stable formulations presented viscosity over 100 cP and ratio between the surface tension of the emulsion and the mucilage of over 1. These two answers were selected, since they better represent the behavior of emulsions in terms of stability and could be used as tools for an initial selection of the most promising formulations. PMID:25793301

  12. Evaluation of the stability of concentrated emulsions for lemon beverages using sequential experimental designs.

    PubMed

    Almeida, Teresa Cristina Abreu; Larentis, Ariane Leites; Ferraz, Helen Conceição

    2015-01-01

    The study of the stability of concentrated oil-in-water emulsions is imperative to provide a scientific approach for an important problem in the beverage industry, contributing to abolish the empiricism still present nowadays. The use of these emulsions would directly imply a reduction of transportation costs between production and the sales points, where dilution takes place. The goal of this research was to evaluate the influence of the main components of a lemon emulsion on its stability, aiming to maximize the concentration of oil in the beverage and to correlate its physicochemical characteristics to product stability, allowing an increase of shelf life of the final product. For this purpose, analyses of surface and interface tension, electrokinetic potential, particle size and rheological properties of the emulsions were conducted. A 2(4-1) fractional factorial design was performed with the following variables: lemon oil/water ratio (30% to 50%), starch and Arabic gum concentrations (0% to 30%) and dioctyl sodium sulfosuccinate (0 mg/L to 100 mg/L), including an evaluation of the responses at the central conditions of each variable. Sequentially, a full design was prepared to evaluate the two most influential variables obtained in the first plan, in which concentration of starch and gum ranged from 0% to 20%, while concentration of lemon oil/water ratio was fixed at 50%, without dioctyl sodium sulfosuccinate. Concentrated emulsions with stability superior to 15 days were obtained with either starch or Arabic gum and 50% lemon oil. The most stable formulations presented viscosity over 100 cP and ratio between the surface tension of the emulsion and the mucilage of over 1. These two answers were selected, since they better represent the behavior of emulsions in terms of stability and could be used as tools for an initial selection of the most promising formulations. PMID:25793301

  13. On bifurcations, voltage collapse and load modeling

    Microsoft Academic Search

    C. A. Canizares

    1995-01-01

    This paper discusses the relation between bifurcations and power systems stability through a thorough analysis of several examples, to clarify some ideas regarding the usefulness and limitations of bifurcation theory in network studies and operation, particularly in voltage stability related issues. Different types of load models are used in a sample system to analyze their effect on system stability and

  14. Improved cycle stability and high-rate capability of Li3VO4-coated Li[Ni0.5Co0.2Mn0.3]O2 cathode material under different voltages

    NASA Astrophysics Data System (ADS)

    Huang, Yan; Jin, Feng-Min; Chen, Fang-Jie; Chen, Li

    2014-06-01

    Li3VO4-coated Li[Ni0.5Co0.2Mn0.3]O2 cathode material exhibits much better cycling stability, rate capability, and high voltage cycling behavior than pristine Li[Ni0.5Co0.2Mn0.3]O2 at room temperature. The sample coated with 3 wt.% Li3VO4 shows the optimum electrochemical performance. It delivers a capacity of 61.5 mAh g-1 at 10 C (1800 mA g-1) after 100 cycles. The capacity retention at 1 C (180 mA g-1) is 63.5% at cut-off voltage 4.6 V, and 63.0% at a higher cut-off voltage 4.8 V. XRD and XPS results reveal that the Li3VO4 coating layer reinforces the surface of matrix material, which benefits structural stability of Li[Ni0.5Co0.2Mn0.3]O2 during long-term cycling. CV and EIS tests indicate that the improvement of electrochemical performances could be attributed to higher Li+ conductivity, suppression of Co and Mn dissolution from Li[Ni0.5Co0.2Mn0.3]O2, and decreased polarization during cycling since Li3VO4 layer on Li[Ni0.5Co0.2Mn0.3]O2 surface acts as a relatively stable protective barrier as well as an excellent Li-ion conductor.

  15. Evaluation of the Magnesium Hydroxide Treatment Process for Stabilizing PFP Plutonium/Nitric Acid Solutions

    SciTech Connect

    Gerber, Mark A.; Schmidt, Andrew J.; Delegard, Calvin H.; Silvers, Kurt L.; Baker, Aaron B.; Gano, Susan R.; Thornton, Brenda M.

    2000-09-28

    This document summarizes an evaluation of the magnesium hydroxide [Mg(OH)2] process to be used at the Hanford Plutonium Finishing Plant (PFP) for stabilizing plutonium/nitric acid solutions to meet the goal of stabilizing the plutonium in an oxide form suitable for storage under DOE-STD-3013-99. During the treatment process, nitric acid solutions bearing plutonium nitrate are neutralized with Mg(OH)2 in an air sparge reactor. The resulting slurry, containing plutonium hydroxide, is filtered and calcined. The process evaluation included a literature review and extensive laboratory- and bench-scale testing. The testing was conducted using cerium as a surrogate for plutonium to identify and quantify the effects of key processing variables on processing time (primarily neutralization and filtration time) and calcined product properties.

  16. Evaluation of lime-fly ash stabilized bases and subgrades using static and dynamic deflection systems 

    E-print Network

    Raba, Gary W.

    1982-01-01

    distributions within a layered system cannot be easily measured, the measurement of pavement deflection has been universally recognized as an indicator of the pavement's structural capacity. In 1955, results from the WASHO Road Test established the values...EVALUATION OF LIME-FLY ASH STABILIZED BASFS AND SUBGRADES USING STATIC AND DYNAMIC DEFLECTION SYSTEMS A Thesis GARY W. RABA Submitted to the Graduate College of Texas AIIM University in partial fulfillment of the requirements for the degree...

  17. Synthesis and Light Stabilizing Ability Evaluation of a Series of Hindered Piperidine Derivatives

    Microsoft Academic Search

    Wei Chen; Ping An; Yan-Xue Chen; Yang Li; Xi-Long Yan; Li-Gong Chen

    2011-01-01

    A series of novel hindered amine light stabilizers (HALS) containing four hindered amine groups were designed and synthesized from diamines, methyl acrylate and 2,2,6,6-pentamethyl-piperidine-4-ol through Michael addition and transesterification. The structures of target compounds were confirmed by H NMR and C NMR. Two of them were chosen to be evaluated for their antioxidation and anti-aging properties, compared with HALS Tinuvin

  18. Critical evaluation of the midgap-voltage-shift method for determining oxide trapped charge in irradiated MOS devices

    SciTech Connect

    Shanfield, Z.; Moriwaki, M.M.

    1987-12-01

    The validity of using midgap voltage shifts to determine radiation-induced oxide trapped charge is examined using thermally stimulated current (TSC), conductance, and C-V techniques. The assumption behind the midgap technique that all interface states are amphoteric P/sub b/ centers is shown to be not generally valid. Conductance measurements revealed a donor interface state in the upper half of the bandgap. Results obtained by combining data from TSC and high-frequency C-V measurements show the existence of three types of radiation-induced interface states: the P/sub b/ center, a donor state in the upper half of the bandgap, and an acceptor state in the lower half. No single surface potential exists that is the neutral point for N/sub it/ for all processes and radiation doses. Midgap voltage shifts do not generally correlate with oxide trapped charge determined from thermally stimulated current (TSC) measurements. The magnitude of the fractional deviation is typically less than a factor of unity but in some cases is as large as a factor of four. The significance of these errors needs to be determined for each application. Arguments and test supporting the validity of using TSC measurements for determining oxide trapped charge are presented.

  19. An assessment of techniques for evaluating the physical stability of parenteral emulsions.

    PubMed

    Zhang, Xiaoguang; Kirsch, Lee E

    2003-01-01

    The physical stability of the parenteral emulsions is a key product quality issue. The purpose of this study is to develop, prepare and characterize model phospholipid emulsions and to critically evaluate various physical stability-indicating methods. Oil-in-water (O/W) emulsions were prepared using 20% (w/w) medium chain triglycerides (MCT) or soybean oil in 2.21% (w/w) aqueous glycerin solutions emulsified with 0.1 to 1.8 % (w/w) lecithin. The reproducibility of emulsion preparation was determined by measuring the volume-based mean droplet diameter using photon correlation spectroscopy (PCS) and zeta potential using electrophoretic light scattering. Evaluation of stability-indicating methods was conducted by comparing the mean droplet growth rate of a thermally-stressed emulsion using PCS, a light obscuration particle counter (HIAC, equipped with a laser diode sensor) and a droplet image analyzer interfaced with transmission electron microscopy (TEM) using osmium tetraoxide fixation. Emulsions with identical compositions and preparation properties had reproducible mean droplet diameter and initial zeta potential values with RSD < 5.0%. Upon the application of thermal stress, the volume-based diameter increased linearly with time for all three sizing techniques (PCS, HIAC, and TEM). The droplet growth rates estimated using PCS and TEM were nearly identical. PCS is a sufficiently accurate technique for measuring emulsion stability and is less time-consuming than TEM. The HIAC technique only measured the size of droplets with diameters larger than about 1 micron, which was considerably greater than the mean droplet diameter as determined by PCS and microscopic image analysis (TEM). Moreover, the growth rate obtained using HIAC was much greater than the rates estimated by PCS and TEM; therefore the HIAC technique was not an accurate measure of the physical stability of the thermally stressed emulsions. PMID:14558703

  20. Analysis of static noise margin improvement for low voltage SRAM composed of nano-scale MOSFETs with ideal subthreshold factor and small variability

    NASA Astrophysics Data System (ADS)

    Tanaka, Chika; Saitoh, Masumi; Ota, Kensuke; Numata, Toshinori

    2015-07-01

    An ultra-low voltage performance of nanowire-transistors-based SRAM cell is investigated using the SPICE model parameters extracted from measurement data. The impact of S-factor and threshold voltage variations on the static noise margin and the minimum operating voltage is evaluated in nanowire transistor as well as in planar bulk transistor and quasi-planar bulk transistor. The performance benefits of undoped nanowire-transistor-based SRAM are measured in terms of the read stability for low voltage and low off leakage current operation.

  1. Tools for voltage collapse assessment

    Microsoft Academic Search

    Claudio A. Canizares; Sameh K. M. Kodsi

    2006-01-01

    A variety of tools and techniques used for voltage stability analysis in power systems are discussed in this paper, with particular emphasis on their application to electricity markets. Thus, the computation of transfer capability limits, which are directly associated with the security constraints used in energy auction systems, by means of continuation power flows (CPF) as well as maximum loadability

  2. Development of an extemporaneous oral liquid formulation of oxandrolone and its stability evaluation.

    PubMed

    Garg, Alka; Garg, Sanjay; She, Richard Wong

    2011-11-01

    Many references exist in the literature identifying the usefulness of oxandrolone in treating muscle wasting due to various conditions including severe burns. However, there is an absence of dosage form alternatives as it is only available as tablets. The dose for children is weight based (0.1 mg/kg) which is difficult to achieve with the currently available tablets of 2.5 mg and 10 mg. The literature provides ample evidence of clinical importance but little guidance on extemporaneous oral liquid formulation of oxandrolone. In order to develop and validate an extemporaneous liquid formulation, suspensions of oxandrolone were developed using locally available (New Zealand) vehicles. Combinations of these vehicles with ethanol, as advised in some articles were also tried. Assay method was developed for oxandrolone using High Performance Liquid Chromatography (HPLC) and Mass Spectroscopy (LC-MS). The formulations were evaluated for stability as per the International Conference on Harmonization (ICH) stability guidelines. They were observed for physical and chemical stability at different time points over a period of 28 days. A stable and validated liquid formulation of oxandrolone has been developed which can be made under the hospital and community pharmacy conditions. The formula utilises commercially available oxandrolone tablets, crushed and dispersed in Simple Syrup BP or Orablend(®) vehicle. The formulation has confirmed stability for 21 days and can be easily made with locally available vehicles. PMID:21764219

  3. EVALUATION OF TWO LEAD-BASED PAINT REMOVAL AND WASTE STABILIZATION TECHNOLOGY COMBINATIONS ON TYPICAL EXTERIOR SURFACES

    EPA Science Inventory

    A study was conducted to demonstrate the effectiveness of a wet abrasive blasting technology to remove lead-based paint from exterior wood siding and brick substrates as well as to evaluate the effectiveness of two waste stabilization technologies to stabilize the resulting blast...

  4. EVALUATING THE EFFECTIVENESS OF STREAMBANK STABILIZATION TECHNIQUES FOR REDUCING BANK EROSION ON THE UPPER CLARK FORK RIVER, WESTERN MONTANA

    Microsoft Academic Search

    Donna DeFrancesco; Paul L. Hansen

    2000-01-01

    Lateral channel movement on the upper Clark Fork River in western Montana has resulted in loss of valuable agricultural land and delivery of sediment and mine tailings into the river. In spring 1996, we initiated a study to evaluate the effectiveness of streambank stabilization techniques to reduce bank erosion. This study examines the effectiveness of 21 different bioengineering stabilization techniques

  5. Stabilization of electro-optic modulator bias voltage drift using a lock-in amplifier and a proportional-integral-derivative controller in a distributed Brillouin sensor system.

    PubMed

    Snoddy, Jeffrey; Li, Yun; Ravet, Fabien; Bao, Xiaoyi

    2007-03-20

    In a distributed Brillouin sensor system, it is crucial to keep the pulse energy uniform for a constant signal-to-noise ratio. This means that the variable dc leakage (pulse base) for the electro-optic modulator (EOM) must be locked. We examine two different methods of locking the EOM bias voltage and look at the advantages and disadvantages of each locking method. It is found that the two locking methods, one based on a lock-in amplifier and the other using proportional-integral-derivative control, both have applications in which they excel at locking the pulse base. PMID:17334439

  6. Node Disjoint Multipath Routing Considering Link and Node Stability protocol: A characteristic Evaluation

    E-print Network

    Upadhayaya, Shuchita

    2010-01-01

    Mobile Ad hoc Networks are highly dynamic networks. Quality of Service (QoS) routing in such networks is usually limited by the network breakage due to either node mobility or energy depletion of the mobile nodes. Also, to fulfill certain quality parameters, presence of multiple node-disjoint paths becomes essential. Such paths aid in the optimal traffic distribution and reliability in case of path breakages. Thus, to cater various challenges in QoS routing in Mobile Add hoc Networks, a Node Disjoint Multipath Routing Considering Link and Node Stability (NDMLNR) protocol has been proposed by the authors. The metric used to select the paths takes into account the stability of the nodes and the corresponding links. This paper studies various challenges in the QoS routing and presents the characteristic evaluation of NDMLNR w.r.t various existing protocols in this area.

  7. Initial Flight Evaluation of the Army/NASA RASCAL Variable Stability Helicopter

    NASA Technical Reports Server (NTRS)

    Moralez, Ernesto, III; Hindson, William S.; Arterburn, David R.

    2000-01-01

    NASA Ames Research Center and the U.S. Army Aeroflightdynamics Directorate (AFDD) [will] have performed initial flight evaluations of the Research Flight Control System (RFCS) that has been integrated into the Army/NASA Rotorcraft Aircrew Systems Concepts Airborne Laboratory (RASCAL) variable stability helicopter. The RASCAL, a highly modified JUH-60A Black Hawk helicopter, is a variable-stability, in-flight simulator that is designed to support flight research programs that leverage on the flight control and handling qualities design tools developed by the Army and NASA. These tools are used in the flight control design life cycle from initial concept definition, through simulation, and ultimately into flight on-board the RASCAL helicopter. The RASCAL will be used to validate methodologies for reducing design cycle costs for new or modified aircraft, and it will serve as a base for the investigation of new rotorcraft technology.

  8. Partial discharge testing under direct voltage conditions

    NASA Technical Reports Server (NTRS)

    Bever, R. S.; Westrom, J. L.

    1982-01-01

    DC partial discharge (PD) (corona) testing is performed using a multichannel analyzer for pulse storing, and data is collected during increase of voltage and at quiescent voltage levels. Thus high voltage ceramic disk capacitors were evaluated by obtaining PD data interspersed during an accelerated life test. Increased PD activity was found early in samples that later failed catastrophically. By this technique, trends of insulation behavior are revealed sensitively and nondestructively in high voltage dc components.

  9. Implant stability evaluation by resonance frequency analysis in the fit lock technique. A clinical study

    PubMed Central

    Falisi, Giovanni; Galli, Massimo; Velasquez, Pedro Vittorini; Rivera, Juan Carlos Gallegos; Di Paolo, Carlo

    2013-01-01

    Summary Surgical procedures for the application of implants in the lateral-superior sectors are affected by the availability of the residual bone. When this condition is lower than 5 mm it is recommended that techniques involving two therapeutic phases, a reconstructive and an applicative one, as reported in the international literature, are adopted. The authors propose here a new method with the potential to apply implants simultaneously with the reconstructive phase. The aim of this longitudinal retrospective study was to evaluate the stability of implants applied with the fit lock technique in the upper maxillarys in us with bone availability lower than 4 mm by measuring resonance frequency at different follow-up periods The seme as urements, carried out on 30 implants, were analysed with specific statistical procedures. The results indicate that the stability of the implants inserted with the fit lock method increases progressively over time in a statistically significant manner. The stability recorded after one year from the insertion (ISQ T2) is significantly higher than that recorded after six months (ISQ T1), and this is significantly higher than that recorded at the time of implant placement (ISQ T0). The implants inserted in the maxillary zones with scarce bone availability and applied with this technique showed a similar stability as reported with other techniques. In light of the results, the authors confirm that the primary stability represents the basic requirement to guarantee a correct healing of the implant and demonstrate that the fit lock technique also all ows reaching this condition when bone availability is minimal. PMID:23991271

  10. An evaluation of stability by thermogravimetric analysis of digestate obtained from different biowastes.

    PubMed

    Gómez, X; Cuetos, M J; García, A I; Morán, A

    2007-10-01

    Research was carried out with the aim of monitoring anaerobic digestion processes using thermal analysis with the aid of mass spectrometry so as to define the stability of the digestate obtained. Three different systems were investigated under varying conditions. The digestion of waste sludge from a pharmaceutical industry (PI) and the digestion of cattle manure (CM) were evaluated under mesophilic conditions. The co-digestion of a mixture of primary sludge (PS) and the organic fraction of municipal solid wastes (OFMSW) was studied under thermophilic conditions. Temperature-programmed combustion tests were carried out to investigate the degree of stabilization of samples throughout the digestion processes. The derivative thermogravimetry (DTG) profiles obtained for the mesophilic digestion of PI waste showed a decrease at low temperatures and an increase at high temperatures in the intensity of the peaks recorded as the stabilization process proceeded. These results are in accordance with those obtained by the present authors in their previous work on the mesophilic digestion of primary sludge and OFMSW. In contrast, the DTG profiles obtained from the stabilization process of CM and thermophilic codigestion of PS and OFMSW showed a reduction in peaks at high temperatures. When the stabilization products obtained from CM by anaerobic digestion and by composting processes were compared, it was observed that the composting process was capable of further decomposing materials readily oxidized at low temperatures and increasing the presence of structurally more complex substances. The evolution of the differential thermal analysis (DTA) signal recorded simultaneously showed considerable similarity to the mass/charge (m/z) signal 44 registered by the mass spectrometer. The use of mass spectrometry helped to clarify the inner workings of the digestion process. PMID:17448599

  11. Evaluation of functional stability of quercetin as a raw material and in different topical formulations by its antilipoperoxidative activity

    Microsoft Academic Search

    Rúbia Casagrande; Sandra R. Georgetti; Waldiceu A. Verri Jr; José R. Jabor; Antonio C. Santos; Maria J. V. Fonseca

    2006-01-01

    The present study evaluates the antioxidant activity of the flavonol quercetin, and its functional stability as a raw material\\u000a and when added in formulations. The iron-chelating activity was determined using the bathophenanthroline assay, and the functional\\u000a stability was evaluated with the antilipoperoxidative assay. Raw material presented concentration-dependent antilipoperoxidative\\u000a and iron-chelating activities. The initial antilipoperoxidative activity of the raw material, cream

  12. Evaluation of the probability of arrester failure in a high-voltage transmission line using a Q learning artificial neural network model

    NASA Astrophysics Data System (ADS)

    Ekonomou, L.; Karampelas, P.; Vita, V.; Chatzarakis, G. E.

    2011-04-01

    One of the most popular methods of protecting high voltage transmission lines against lightning strikes and internal overvoltages is the use of arresters. The installation of arresters in high voltage transmission lines can prevent or even reduce the lines' failure rate. Several studies based on simulation tools have been presented in order to estimate the critical currents that exceed the arresters' rated energy stress and to specify the arresters' installation interval. In this work artificial intelligence, and more specifically a Q-learning artificial neural network (ANN) model, is addressed for evaluating the arresters' failure probability. The aims of the paper are to describe in detail the developed Q-learning ANN model and to compare the results obtained by its application in operating 150 kV Greek transmission lines with those produced using a simulation tool. The satisfactory and accurate results of the proposed ANN model can make it a valuable tool for designers of electrical power systems seeking more effective lightning protection, reducing operational costs and better continuity of service.

  13. Health-hazard evaluation report HETA 86-339-1741, EMCO High Voltage Company, Sutter Creek, California

    SciTech Connect

    Belanger, P.L.

    1986-10-01

    Possible exposure to several chemical substances during the fabrication of power-supply modules was investigated at the EMCO High Voltage Company, Sutter Creek, California, at the request of an employee. Environmental air samples were collected during the coating and developing process and during the epoxy potting operation. Samples were analyzed for chlorobenzene and xylenes; no overexposures were registered. No overexposure was observed to butyl-glycidyl-ether and no detectable levels of epichlorohydrin, cyclohexanone, 2-methoxyethanol, or 2-ethoxyethanol were found. During the pot soldering operation there was a potential for exposure to the fluxing agent, 3% hydrochloric-acid, and the operator had complained of throat and nose irritation. The author recommends that the fabrication operator wear protective gloves during coating and developing of copper boards. Gloves and goggles should be worn when weighing out the sodium-persulfate and when removing panels from the bench top etcher. Local exhaust ventilation with a movable duct should be used during the pot soldering operation.

  14. SLOPE STABILITY EVALUATION AND EQUIPMENT SETBACK DISTANCES FOR BURIAL GROUND EXCAVATIONS

    SciTech Connect

    MCSHANE DS

    2010-03-25

    After 1970 Transuranic (TRU) and suspect TRU waste was buried in the ground with the intention that at some later date the waste would be retrieved and processed into a configuration for long term storage. To retrieve this waste the soil must be removed (excavated). Sloping the bank of the excavation is the method used to keep the excavation from collapsing and to provide protection for workers retrieving the waste. The purpose of this paper is to document the minimum distance (setback) that equipment must stay from the edge of the excavation to maintain a stable slope. This evaluation examines the equipment setback distance by dividing the equipment into two categories, (1) equipment used for excavation and (2) equipment used for retrieval. The section on excavation equipment will also discuss techniques used for excavation including the process of benching. Calculations 122633-C-004, 'Slope Stability Analysis' (Attachment A), and 300013-C-001, 'Crane Stability Analysis' (Attachment B), have been prepared to support this evaluation. As shown in the calculations the soil has the following properties: Unit weight 110 pounds per cubic foot; and Friction Angle (natural angle of repose) 38{sup o} or 1.28 horizontal to 1 vertical. Setback distances are measured from the top edge of the slope to the wheels/tracks of the vehicles and heavy equipment being utilized. The computer program utilized in the calculation uses the center of the wheel or track load for the analysis and this difference is accounted for in this evaluation.

  15. A battery-based, low-noise voltage source

    NASA Astrophysics Data System (ADS)

    Wagner, Anke; Sturm, Sven; Schabinger, Birgit; Blaum, Klaus; Quint, Wolfgang

    2010-06-01

    A highly stable, low-noise voltage source was designed to improve the stability of the electrode bias voltages of a Penning trap. To avoid excess noise and ground loops, the voltage source is completely independent of the public electric network and uses a 12 V car battery to generate output voltages of ±15 and ±5 V. First, the dc supply voltage is converted into ac-voltage and gets amplified. Afterwards, the signal is rectified, filtered, and regulated to the desired output value. Each channel can deliver up to 1.5 A. The current as well as the battery voltage and the output voltages can be read out via a universal serial bus (USB) connection for monitoring purposes. With the presented design, a relative voltage stability of 7×10-7 over 6.5 h and a noise level equal or smaller than 30 nV/?Hz is achieved.

  16. Section IV.D.3 for DOE 2013 Annual Report: Novel Phosphazene-based Compounds to Enhance Safety and Stability of Cell Chemistries for High Voltage Applications (INL)

    SciTech Connect

    Kevin L. Gering; Mason K. Harrup; Eric J. Dufek; Sergiy V. Sazhin; Harry W. Rollins; David K. Jamison; Fred F. Stewart; John Burba

    2013-09-01

    Electrolytes play a central role in performance and aging in most electrochemical systems. As automotive and grid applications place a higher reliance on electrochemical stored energy, it becomes more urgent to have electrolyte components that enable optimal battery performance while promoting battery safety and longevity. Safety remains a foremost concern for widespread utilization of Li-ion technology in electric-drive vehicles, especially as the focus turns to higher voltage systems (5V). This work capitalizes on the long established INL expertise regarding phosphazene chemistry, aimed at battery-viable compounds for electrolytes and electrodes that are highly tolerant to abusive conditions. This report showcases our 2013 work for the DOE applied battery research (ABR) program, wherein testing results are summarized for INL electrolytes and alternative anode materials.

  17. Evaluation of Thermal Stability of Nomex® Brand Paper in Main Transformer of Shinkansen Train Series 100

    NASA Astrophysics Data System (ADS)

    Tanaka, Hirokazu; Kondo, Chihiro; Naruse, Shinji; Ishii, Yoshitada

    Nomex® brand paper has been used as wire wrapping insulation material of main transformers of Shinkansen Train Series 100 with silicone oil. After approximately 12-13 years service, 8 transformers of Series 100 were sampled to evaluate degradation of Nomex® brand paper in terms of tensile strength and intrinsic viscosity. All data were compared with initial data. The result of less degradation shows Nomex® has good thermal stability in silicone oil in the main transformer of Shinkansen Train which were used in very severe condition.

  18. Combined Use of Automatic Tube Voltage Selection and Current Modulation with Iterative Reconstruction for CT Evaluation of Small Hypervascular Hepatocellular Carcinomas: Effect on Lesion Conspicuity and Image Quality

    PubMed Central

    Lv, Peijie; Liu, Jie; Zhang, Rui; Jia, Yan

    2015-01-01

    Objective To assess the lesion conspicuity and image quality in CT evaluation of small (? 3 cm) hepatocellular carcinomas (HCCs) using automatic tube voltage selection (ATVS) and automatic tube current modulation (ATCM) with or without iterative reconstruction. Materials and Methods One hundred and five patients with 123 HCC lesions were included. Fifty-seven patients were scanned using both ATVS and ATCM and images were reconstructed using either filtered back-projection (FBP) (group A1) or sinogram-affirmed iterative reconstruction (SAFIRE) (group A2). Forty-eight patients were imaged using only ATCM, with a fixed tube potential of 120 kVp and FBP reconstruction (group B). Quantitative parameters (image noise in Hounsfield unit and contrast-to-noise ratio of the aorta, the liver, and the hepatic tumors) and qualitative visual parameters (image noise, overall image quality, and lesion conspicuity as graded on a 5-point scale) were compared among the groups. Results Group A2 scanned with the automatically chosen 80 kVp and 100 kVp tube voltages ranked the best in lesion conspicuity and subjective and objective image quality (p values ranging from < 0.001 to 0.004) among the three groups, except for overall image quality between group A2 and group B (p = 0.022). Group A1 showed higher image noise (p = 0.005) but similar lesion conspicuity and overall image quality as compared with group B. The radiation dose in group A was 19% lower than that in group B (p = 0.022). Conclusion CT scanning with combined use of ATVS and ATCM and image reconstruction with SAFIRE algorithm provides higher lesion conspicuity and better image quality for evaluating small hepatic HCCs with radiation dose reduction. PMID:25995682

  19. High voltage power transistor development

    NASA Technical Reports Server (NTRS)

    Hower, P. L.

    1981-01-01

    Design considerations, fabrication procedures, and methods of evaluation for high-voltage power-transistor development are discussed. Technique improvements such as controlling the electric field at the surface and perserving lifetimes in the collector region which have advanced the state of the art in high-voltage transistors are discussed. These improvements can be applied directly to the development of 1200 volt, 200 ampere transistors.

  20. Technical evaluation of the adequacy of station electric distribution system voltages for the Rancho Seco Nuclear Generating Station, Unit No. 1: selected issues program (Docket No. 50-312)

    SciTech Connect

    White, R. L.

    1981-11-10

    This report documents the technical evaluation of the adequacy of the station electric distribution system voltages for the Rancho Seco Nuclear Generation Station, Unit No. 1. The evaluation is to determine if the onsite distribution system, in conjunction with the offsite power sources, has sufficient capacity to automatically start and operate all Class 1E loads within the equipment voltage ratings under certain conditions established by the Nuclear Regulatory Commission. The licensee demonstrates with the analysis that with certain modifications the guidelines and requirements of the NRC will be met.

  1. Evaluation of the stability of enterovirus 71 virus-like particle.

    PubMed

    Lin, Shih-Yeh; Chung, Yao-Chi; Chiu, Hsin-Yi; Chi, Wei-Kuang; Chiang, Bor-Luen; Hu, Yu-Chen

    2014-03-01

    Enterovirus 71 (EV71) is responsible for the outbreaks of hand-foot-and-mouth disease that caused significant mortality in children, but no vaccine is available yet. EV71 virus-like particle (VLP) is the empty capsid consisting of viral structural proteins but can elicit potent immune responses, rendering VLP a promising EV71 vaccine candidate. To evaluate whether VLP remains stable after long-term storage, which is crucial for advancing the VLP vaccine to the clinical setting, we evaluated the effects of NaCl concentration, buffers and temperatures on the VLP stability. We first validated the use of dynamic light scattering (DLS) for measuring the hydrodynamic diameter (?30-35 nm) of VLP, which was close to the VLP diameter (?25-27 nm) as measured by transmission electron microscopy (TEM). Using these techniques, we found that EV71 VLP remained stable for 5 months in sodium phosphate (NaPi) buffers with various NaCl concentrations. EV71 VLP also remained morphologically stable in NaPi, citrate and TE(+) buffers for 5 months, yet the enzyme-linked immunosorbent assay (ELISA) revealed that the VLP stored in citrate and TE(+) buffers partially lost the immunogenicity after 5 months. In contrast, the VLP stored in the NaPi buffer at 4°C remained stable macroscopically and microscopically for 5 months, as judged from the DLS, TEM and ELISA. The VLP stored at 25°C and 37°C also retained stability for 1 month, which would obviate the need of a cold chain during the shipping. These data altogether proved the stability of EV71 VLP and suggested that the VLP is amenable to bioprocessing and storage. PMID:24140131

  2. Long Term Stability Evaluation of Prostacyclin Released from Biomedical Device Through Turbiscan Lab Expert

    PubMed Central

    Celia, Christian; Locatelli, Marcello; Cilurzo, Felisa; Cosco, Donato; Gentile, Emanuela; Scalise, Daniela; Carafa, Maria; Ventura, Cinzia Anna; Fleury, Mathias; Tisserand, Christelle; Barbacane, Renato C.; Fresta, Massimo; Marzio, Luisa Di; Paolino, Donatella

    2015-01-01

    Therapeutic guidelines indicate prostacyclin as the first line of treatment in inflammation and vascular diseases. Prostacyclins prevent formation of the platelet plug involved in primary hemostasis by inhibiting platelet activation and, combined with thromboxane, are effective vasodilators in vascular damage. Trans-Atlantic Inter-Society Consensus Document on Management of Peripheral Arterial Disease II guidelines indicates prostacyclins; in particular, Iloprost, as the first therapeutic option for treating peripheral arterial disease. However, therapeutic efficacy of Iloprost has witnessed several drawbacks that have occurred in patients receiving repeated weekly administration of the drug by intravenous infusions. Adverse reactions arose under perfusion with Iloprost for 6 h and patient compliance was drastically decreased. Biomedical devices could provide a suitable alternative to overcome these drawbacks. In particular, elastomeric pumps, filled with Iloprost isotonic solution, could slowly release the drug, thus decreasing its side effects, representing a valid alternative to hospitalization of patients affected by peripheral arterial disease. However, the home therapy treatment of patients requires long-term stability of Iloprost in solution-loaded elastomeric pumps. The aim of this work was to investigate the long-term stability of Iloprost isotonic solution in biomedical devices using Turbiscan technology. Turbiscan Lab Expert (L’Union, France) predicts the long-term stability of suspensions, emulsions and colloidal formulations by measuring backscattering and transmission of particulates dispersed in solution. The formulations were evaluated by measuring the variation of physical-chemical properties of colloids and suspensions as a function of backscattering and transmission modifications. In addition, the release profile of Iloprost isotonic solution from the biomedical device was evaluated. PMID:25381994

  3. Evaluation of PFP Furnace Systems for Thermal Stabilization of Washed High Chloride Plutonium Oxide Items

    SciTech Connect

    Fischer, Christopher M.; Elmore, Monte R.; Schmidt, Andrew J.; Gerber, Mark A.; Muzatko, Danielle S.; Gano, Susan R.; Thornton, Brenda M.

    2002-12-17

    High chloride content plutonium (HCP) oxides are impure plutonium oxide scrap which contains NaCl, KCl, MgCl2 and/or CaCl2 salts at potentially high concentrations and must be stabilized at 950 C per the DOE Standard, DOE-STD-3013-2000. The chlorides pose challenges to stabilization because volatile chloride salts and decomposition products can corrode furnace heating elements and downstream ventilation components. A high-temperature furnace (same make and model as used at the RMC at Plutonium Finishing Plant) and the associated offgas system were set up at PNNL to identify system vulnerabilities and to investigate alternative materials and operating conditions that would mitigate any corrosion and plugging of furnace and offgas components. The key areas of interest for this testing were the furnace heating elements, the offgas line located inside the furnace, the offgas line between the furnace and the filter/knockout pot, the filter/knockout pot, the sample boat, and corrosion coupons to evaluate alternative materials of construction. The evaluation was conducted by charging the furnace with CeO2 that had been impregnated with a mixture of chloride salts (selected to represent the expected residual chloride salt level in washed high chloride items) and heated in the furnace in accordance with the temperature ramp rates and hold times used at PFP.

  4. Secondary voltage control based on multiple objective linear programming

    Microsoft Academic Search

    Zhihao Yun; Hengxu Zhang; Yutian Liu; Hong Mu; Ming Lei

    2005-01-01

    The hierarchical voltage control has been proved to be an effective method to ensure the security, stability and economy operation in power systems. The secondary voltage control is represented by the multiple objective linear programming with sensitive analysis in this paper. Several control objectives are considered. The first objective is that the pilot node voltage should be close enough to

  5. Evaluation of dynamic postural balance using the Biodex Stability System in rheumatoid arthritis patients.

    PubMed

    Aydo?, Ece; Bal, Ajda; Aydo?, Sedat Tolga; Cakci, Aytül

    2006-07-01

    The aim of this study was to investigate dynamic postural balance in patients with rheumatoid arthritis (RA) in relation to the disease characteristics. Seventy-four patients with RA and 42 controls of the same age group were tested using the Biodex Stability System (Biodex Medical Systems, Shirley, NY, USA). Anterior/posterior (AP), medial/lateral (ML), and overall (OA) indices were obtained with bilateral stance at platform stabilities of 2 and 8. Subjects were tested with "eyes open" at all times. At the same time, Disease Activity Score, functional disability [Health Assessment Questionnaire, (HAQ)], and Steinbrocker Functional Class (SFC) were assessed. Both the AP and OA indices in the RA group were significantly higher than in the control group for level 8. For OA index, the results were 2.7+/-0.9 in RA and 2.2+/-0.7 in the control group (p=0.006), and for AP index, the results were 2.1+/-0.7 in RA and 1.7+/-0.6 in the control group (p=0.002). Eleven patients (15.9%) and three controls (7.1%) could not complete the test at level 2. When the patients and controls who completed the test were compared, a significant difference was found only in the ML index. The results were 4.6+/-2.4 in RA and 3.8+/-1.6 in the control group (p=0.047). A positive correlation between HAQ and postural balance for all three stability indices at level 8 was detected. A positive correlation between SFC and postural balance for OA and ML at level 8 was also found. Multiple linear regression analyses revealed age and body mass index (BMI) to be the most important factors influencing postural dynamic balance at both levels in the RA group and in healthy controls. RA has a negative effect on dynamic postural stability. The functional status affects dynamic balance more than disease activity. Age and BMI were the most important factors influencing postural dynamic balance in the RA group and in healthy controls. Level 2 does not appear to be an appropriate level for evaluating postural stability in RA. PMID:16247584

  6. Stability evaluation of a rocket engine for gaseous oxygen difluoride (OF2) and gaseous diborane (B2H6) propellants

    NASA Technical Reports Server (NTRS)

    Clayton, R. M.

    1972-01-01

    Results of an experimental evaluation of the dynamic stability of a candidate combustor for the space storable propellants gaseous OF2/B2H6 show that the combustor is unstable without supplementary damping. A computer analysis indicated that the uninhibited engine could be unstable. The experiments, conducted with O2/C2H4 substitute propellants and with 70-30 FLOX/B2H6 (OF2 simulated with FLOX), show that the uninhibited combustor has a low stability margin to starting transient perturbations, but that is relatively insensitive to bomb disturbances. Damping cavities are shown to provide stability.

  7. Evaluation of different amendments to stabilize antimony in mining polluted soils.

    PubMed

    Álvarez-Ayuso, E; Otones, V; Murciego, A; García-Sánchez, A

    2013-02-01

    Soil pollution with antimony is of increasing environmental concern worldwide. Measures for its control and to attenuate the risks posed to the ecosystem are required. In this study the application of several iron and aluminium oxides and oxyhydroxides as soil amendments was evaluated in order to assess their feasibility to stabilize Sb in mining polluted soils. Mine soils with different pollution levels were amended with either goethite, ferrihydrite or amorphous Al oxide at various ratios (0-10%). The effectiveness of such treatments was assessed by both batch and column leaching tests. The use of ferrihydrite or amorphous Al oxide proved to be highly effective to stabilize Sb. Immobilization levels of 100% were found when doses of 5% ferrihydrite or 10% amorphous Al oxide were applied, regardless of the soil Sb load. Column leaching studies also showed a high Sb leaching reduction (>75%) when soils were amended with 1% ferrihydrite or 5% amorphous Al oxide. Moreover, such treatments proved to simultaneously immobilize As and Pb in a great extent when soils were also polluted with such toxic elements. PMID:23121985

  8. Landslides and slope stability evaluation in the historical town of Kruja, Albania

    NASA Astrophysics Data System (ADS)

    Muceku, Y.; Korini, O.

    2013-07-01

    This paper describes the landslides and slope stability evaluation in the urban area of Kruja town, Albania. Kruja is a~historical and heritage center, due to the existence of many important cultural monuments including Skanderbeg castle and Bazaar square etc. The urban area of Kruja town has been affected from the Landslides effects, in the past and also present. From this phenomenon many engineering objects such as buildings, roads etc. are damaged and demolished. From the engineering geological mapping at scale 1 : 5000 it is observed that many active landslides have dramatically increased in activity after 1980s. The landslide types found in the studied area are earth slides, debris flow, as well as rock fall and rock rolling. Also, from field works and laboratory analysis, the slope stability of whole urban areas has been determined; for this purpose the studied zone is divided into the stable and unstable areas, which helps to better understand the mass movement's activity as one of the most harmful hazards of the geodynamics' phenomena.

  9. Landslide and slope stability evaluation in the historical town of Kruja, Albania

    NASA Astrophysics Data System (ADS)

    Muceku, Y.; Korini, O.

    2014-03-01

    This paper describes landslides and slope stability evaluation in the urban area of Kruja, Albania. Kruja is a historical and heritage center, due to the existence of many important cultural monuments, including "Skanderbeg" castle and Bazaar square, etc. The urban area of Kruja has been affected by landslide effects, in the past and also the present. From this phenomenon many engineering objects such as buildings, roads, etc., are damaged and demolished. From engineering geological mapping at scale 1:5000 it is observed that many active landslides have dramatically increased in activity since the 1980s. The landslide types found in the studied area are earthslides, debris flow, as well as rockfall and rock rolling. Also, from field works and laboratory analysis, the slope stability of the whole urban area has been determined; for this purpose the studied zone is divided into stable and unstable areas, which helps to better understand mass movement activity as one of the most harmful hazards of geodynamic phenomena.

  10. A Preliminary Evaluation of Using Fill Materials to Stabilize Used Nuclear Fuel During Storage and Transportation

    SciTech Connect

    Maheras, Steven J.; Best, Ralph; Ross, Steven B.; Lahti, Erik A.; Richmond, David J.

    2012-08-01

    This report contains a preliminary evaluation of potential fill materials that could be used to fill void spaces in and around used nuclear fuel contained in dry storage canisters in order to stabilize the geometry and mechanical structure of the used nuclear fuel during extended storage and transportation after extended storage. Previous work is summarized, conceptual descriptions of how canisters might be filled were developed, and requirements for potential fill materials were developed. Elements of the requirements included criticality avoidance, heat transfer or thermodynamic properties, homogeneity and rheological properties, retrievability, material availability and cost, weight and radiation shielding, and operational considerations. Potential fill materials were grouped into 5 categories and their properties, advantages, disadvantages, and requirements for future testing were discussed. The categories were molten materials, which included molten metals and paraffin; particulates and beads; resins; foams; and grout. Based on this analysis, further development of fill materials to stabilize used nuclear fuel during storage and transportation is not recommended unless options such as showing that the fuel remains intact or canning of used nuclear fuel do not prove to be feasible.

  11. Optimization of madecassoside liposomes using response surface methodology and evaluation of its stability.

    PubMed

    Wang, Huijuan; Liu, Meifeng; Du, Song

    2014-10-01

    Polar compounds with large molecular weight have poor membrane permeability, liposomes can promote drugs to penetrate epidermis and remain or release at dermis. Madecassoside (MA) exhibits powerful potency in treatment of skin disorders such as wound healing, scar management, and psoriasis, but it is not easy to penetrate epidermis for its hydrophilic nature. The aim of this work is to get the optimum process conditions and evaluate physicochemical properties and physical stability of MA liposomes. In order to avoid this disadvantage and maintain long term drug storage, MA Liposomes were designed to achieve optimum preparation conditions using response surface methodology (RSM) in our experiment. The process and formulation variables were optimized by achieving maximum drug encapsulation efficiency. The optimum conditions were 0.4424 g of madecassoside, 8.174 of ratio of egg yolk lecithin to cholesterol, 65 s of ultrasonic time. The results of particle size, zeta potential and encapsulation efficiency of madecassoside liposomes were 293 nm, -35.6 mV, and 40.90%, respectively, on the basis of the above optimum conditions. According to the morphology of liposomes and encapsulation efficiency of triplicate experiments conducted at optimum conditions, MA liposomes obtained by this optimized formulation had characters of favorable repeatability and proper particle size. The physical stability tests of MA liposomes indicated that its suitable storage temperature was at 4°C with higher encapsulation efficiency. PMID:25014372

  12. Development of a biofilm formation method for waste forms stability evaluation.

    PubMed

    Idachaba, M A; Nyavor, K; Egiebor, N O; Rogers, R D

    2000-10-01

    The development of an accurate assessment protocol is critical for the prediction of long-term performance of waste disposal systems under field conditions. In this study, the development of a biofilm formation method for the evaluation of waste forms stability to microbially induced degradation (MID) is reported. The development process involved significant modifications to the existing Nuclear Regulatory Commission (NRC) approach. In the biofilm formation method, the control media and fermenter broths are designed to be of similar pH to avoid overestimation of the microbe's capability to degrade the waste forms. In the NRC approach, the pH values are different. The existing one-stage process of the NRC approach is also replaced with a two-stage process in the biofilm formation method. This is to ensure full evaluation of the microbe's involvement in waste forms degradation. The first stage of the two-stage process is for biofilm formation and the second is for biofilm evaluation. The use of a two-stage process eliminates the possibility of substrate limitation, resulting in values of degradation indices that are about two times higher than those obtained using the single-stage NRC approach. Two waste forms (100% Tuskegee cement and 21% cobalt chloride/79% cement) were used in the development of the biofilm formation method. Both waste forms showed evidence of biofilm formation. The formation of biofilm on the cobalt-containing waste form indicates a lack of anti-microbial capability of cobalt. PMID:10946124

  13. The Transient-Energy Method of Calculating Stability

    Microsoft Academic Search

    P. C. Magnusson

    1947-01-01

    The transient-energy method is a newly developed means of checking and quantitatively evaluating the transient stability of a system of three, or possibly more synchronous machines. Each machine is represented by a constant-magnitude voltage behind a fixed reactance (usually the transient reactance) and all losses and nonsynchronous loads are assumed to be constant throughout the transient. The method is developed

  14. Toroidal tank evaluation. [propellant tanks for spin-stabilized Pioneer spacecraft

    NASA Technical Reports Server (NTRS)

    Fester, D. A.; Anderson, J. E.

    1977-01-01

    The reported study had been conducted to determine the feasibility of developing toroidal tanks for an auxiliary propulsion system that could be integrated into a Pioneer spin-stabilized spacecraft. The system evaluated consisted of two toroidal tanks equipped with surface tension devices. One tank is intended for nitrogen tetroxide, the other for monomethylhydrazine. The study included the definition of a propellant acquisition system concept that could satisfy the requirements of a spinning tank. It was found that an oxidizer tank spin rate of 76 rpm and a fuel tank spin rate of 110 rpm would be required to produce liquid loss from the acquisition system during spacecraft operation. An investigation showed that toroidal tanks can be fabricated with present technology using either titanium or aluminum alloys. The preferred material would be titanium because of its significantly higher strength.

  15. Evaluation of the Lifetime and Thermal Conductivity of Dysprosia-Stabilized Thermal Barrier Coating Systems

    NASA Astrophysics Data System (ADS)

    Curry, Nicholas; Markocsan, Nicolaie; Östergren, Lars; Li, Xin-Hai; Dorfman, Mitch

    2013-08-01

    The aim of this study was the further development of dysprosia-stabilized zirconia coatings for gas turbine applications. The target for these coatings was a longer lifetime and higher insulating performance compared to today's industrial standard thermal barrier coating. Two morphologies of ceramic top coat were studied: one using a dual-layer system and the second using a polymer to generate porosity. Evaluations were carried out using a laser flash technique to measure thermal properties. Lifetime testing was conducted using thermo-cyclic fatigue testing. Microstructure was assessed with SEM and Image analysis was used to characterize porosity content. The results show that coatings with an engineered microstructure give performance twice that of the present reference coating.

  16. Technical evaluation report (Revision 1) on the proposed design modifications and technical specification changes on grid voltage degradation for the Peach Bottom Atomic Power Station, Units 2 and 3

    SciTech Connect

    Selan, J.C.

    1983-03-11

    This report is a revision of the technical evaluation documented in a separate report dated November 3, 1981 (UCID-19115) on the proposed design modification and Technical Specification changes for the protection of the Class 1E equipment from grid voltage degradation for the Peach Bottom Atomic Power Station, Units 2 and 3. The review criteria are based on several IEEE standards and The Code of Federal Regulations. The evaluation compares the submittals made by the plant with the NRC staff positions and the review criteria. The evaluation finds that the proposed design modifications and the required changes to the Technical Specifications will ensure that the Class 1E equipment will be protected from sustained voltage degradation.

  17. Evaluation of liver tissue damage and grasp stability using finite element analysis.

    PubMed

    Cheng, Lei; Hannaford, Blake

    2014-11-19

    Minimizing tissue damage and maintaining grasp stability are essential considerations in surgical grasper design. Most past and current research analyzing graspers used for tissue manipulation in minimally invasive surgery is based on in vitro experiments. Most previous work assessed tissue injury and grasp security by visual inspection; only a few studies have quantified it. The goal of the present work is to develop a methodology with which to compute tissue damage magnitude and grasp quality that is appropriate for a wide range of grasper-tissue interaction. Using finite element analysis (FEA), four graspers with varying radii of curvature and four graspers with different tooth sizes were analyzed while squeezing and pulling liver tissue. All graspers were treated as surgical steel with linear elastic material properties. Nonlinear material properties of tissue used in the FEA as well as damage evaluation were derived from previously reported in vivo experiments. Computed peak stress, integrated stress, and tissue damage were compared. Applied displacement is vertical and then horizontal to the tissue surface to represent grasp and retraction. A close examination of the contact status of each node within the grasper-tissue interaction surface was carried out to investigate grasp stability. The results indicate less tissue damage with increasing radius of curvature. A smooth wave pattern reduced tissue damage at the cost of inducing higher percentage of slipping area. This methodology may be useful for researchers to develop and test various designs of graspers. Also it could improve surgical simulator performance by reflecting more realistic tissue material properties and predicting tissue damage for the student. PMID:25408249

  18. EVALUATION OF TWO LEAD-BASED PAINT REMOVAL AND WASTE STABILIZATION TECHNOLOGY COMBINATIONS ON TYPICAL EXTERIOR SURFACES: JOURNAL ARTICLE

    EPA Science Inventory

    NRMRL-CIN-1624 Daniels*, A., Kominsky, J.R., and Clark*, P.J. Evaluation of Two Lead-Based Paint Removal and Waste Stabilization Technology Combinations on Typical Exterior Surfaces. Published in: Journal of Hazardous Materials 87 (1-3):117-126 (2001). 10/04/2001 A study was co...

  19. Evaluation of the stability of arsenic immobilized by microbial sulfate reduction using TCLP extractions and long-term leaching techniques

    Microsoft Academic Search

    Tony Jong; David L. Parry

    2005-01-01

    An investigation was conducted to evaluate the stability or leachability of arsenic immobilized by microbial sulfate reduction. Anoxic solid-phase samples taken from a bioreactor previously used to treat metal and As contaminated water using sulfate reducing bacteria (SRB) were subjected to the toxicity characteristic leaching procedure (TCLP) and long-term column leaching tests. The results from TCLP experiments showed that the

  20. INTERNATIONAL WASTE TECHNOLOGIES EVALUATION REPORT SITE PROGRAM DEMONSTRATION, IN-SITU STABILIZATION/SOLIDIFICATION, HIALEAH, FL, VOLUME I

    EPA Science Inventory

    A demonstration of the International Waste Technologies (IWT) process, utilizing the Geo-Con, Inc., deep-soil-mixing equipment has been performed under the Superfund Innovative Technology Evaluation (SITE) Program. his was the first field demonstration of an in situ stabilization...

  1. Investigations on the low voltage cathodoluminescence stability and surface chemical behaviour using Auger and X-ray photoelectron spectroscopy on LiSrBO{sub 3}:Sm{sup 3+} phosphor

    SciTech Connect

    Pitale, Shreyas S., E-mail: shreyas1234@yahoo.com [Department of Physics, University of the Free State, P.O. Box 339, Bloemfontein ZA9300 (South Africa); Nagpure, I.M.; Kumar, Vinay; Ntwaeaborwa, O.M.; Terblans, J.J. [Department of Physics, University of the Free State, P.O. Box 339, Bloemfontein ZA9300 (South Africa)] [Department of Physics, University of the Free State, P.O. Box 339, Bloemfontein ZA9300 (South Africa); Swart, H.C., E-mail: swarthc@ufs.ac.za [Department of Physics, University of the Free State, P.O. Box 339, Bloemfontein ZA9300 (South Africa)

    2011-07-15

    Highlights: {yields} Stable orange-red cathodoluminescence observed from LiSrBO{sub 3}:Sm{sup 3+} phosphor. {yields} In situ Auger electron spectroscopy, while monitoring the CL output reduction, reveals surface concentration modification of Li, Sr, B and O atoms. {yields} X-ray photoelectron spectroscopy confirms the formation of SrO{sub 2} layer due to the electron stimulated surface chemical reactions (ESSCRs). This layer is possibly contributing to the surface chemical stability and prevents further degradation. -- Abstract: Orange-red emissive LiSrBO{sub 3}:Sm{sup 3+} phosphors were synthesized through the solid-state reaction method. Under UV radiation (221 nm) and low-voltage electron beam (2 keV, 12 mA/cm{sup 2}) excitation, the Sm{sup 3+} doped LiSrBO{sub 3} phosphor shows emission corresponding to the characteristic {sup 4}G{sub 5/2}-{sup 6}H{sub 7/2} transitions of Sm{sup 3+} with the strongest emission at 601 nm. A high stability of cathodoluminescence (CL) emission during prolong electron bombardment with low-energy electrons was observed. Surface sensitive diagnostic tools such as Auger electron spectroscopy (AES) and X-ray photoelectron spectroscopy (XPS) were used to study the surface chemistry. AES results revealed modifications in the surface concentrations of Li, Sr, B, O and C on the surface of the LiSrBO{sub 3}:Sm{sup 3+} phosphor as indicated by the changes in their Auger peak to peak heights (APPH) as a function of electron dose. Observed changes in the high resolution XPS spectra of the LiSrBO{sub 3}:Sm{sup 3+} surface irradiated with the low energy electron beam provide evidence of compositional and structural changes as a result of the electron beam stimulated surface chemical reactions (ESSCRs). Additional SrO{sub 2} was identified by XPS on the phosphor surface after it received an electron dose of 300 C/cm{sup 2} together with the increase in the concentrations of chemical species containing the B-C-O bonding. The new surface chemical species formed during electron beam bombardment are possibly responsible for the stability of the CL in the LiSrBO{sub 3}:Sm{sup 3+} phosphor.

  2. Bioremediation of Contaminated Lake Sediments and Evaluation of Maturity Indicies as Indicators of Compost Stability

    PubMed Central

    Rekha, P.; Suman Raj, D. S.; Aparna, C.; Bindu, V. Hima; Anjaneyulu, Y.

    2005-01-01

    Land contamination is one of the widely addressed problems, which is gaining importance in many developed and developing countries. International efforts are actively envisaged to remediate contaminated sites as a response to adverse health effects. Popular conventional methodologies only transfer the phase of the contaminant involving cost intensive liabilities besides handling risk of the hazardous waste. Physico-chemical methods are effective for specific wastes, but are technically complex and lack public acceptance for land remediation. “Bioremediation”, is one of the emerging low-cost technologies that offer the possibility to destroy various contaminants using natural biological activities. Resultant non -toxic end products due to the microbial activity and insitu applicability of this technology is gaining huge public acceptance. In the present study, composting is demonstrated as a bioremediation methodology for the stabilization of contaminated lake sediments of Hyderabad, A.P, India. Lake sediment contaminated with organics is collected from two stratums – upper (0.25 m) and lower (0.5m) to set up as Pile I (Upper) and Pile II (Lower) in the laboratory. Lime as a pretreatment to the lake sediments is carried out to ensure metal precipitation. The pretreated sediment is then mixed with organic and inorganic fertilizers like cow dung, poultry manure, urea and super phosphate as initial seeding amendments. Bulking agents like sawdust and other micronutrients are provided. Continuous monitoring of process control parameters like pH, moisture content, electrical conductivity, total volatile solids and various forms of nitrogen were carried out during the entire course of the study. The stability of the compost was evaluated by assessing maturity indices like C/N, Cw (water soluble carbon), CNw (Cw/Nw), nitrification index (NH4/NO?3), Cation Exchange Capacity (CEC), germination index, humification ratio, compost mineralization index (ash content/oxidizable carbon), sorption capacity index (CEC/oxidizable carbon). Enzyme activities of agricultural interest like urease, phosphatase, ?-glucosidase, dehydrogenase and BAA-hydrolyzing protease, which are involved in the nitrogen, phosphorus and carbon cycles, were also assessed. Total content of macro and micronutrients in the final compost was also determined to assess the fertilizer value. The studies revealed that composting could be applied as a remediation technology after removing the top sediment. The maturity indices that are evaluated from the present study can be used to validate the success of the remediation technology. PMID:16705825

  3. Evaluation of two lead-based paint removal and waste stabilization technology combinations on typical exterior surfaces.

    PubMed

    Daniels, A E; Kominsky, J R; Clark, P J

    2001-10-12

    A study was conducted to demonstrate the effectiveness of a wet abrasive blasting technology to remove lead-based paint from exterior wood siding and brick substrates as well as to evaluate the effectiveness of two waste stabilization technologies to stabilize the resulting blast media (coal slag and mineral sand) paint debris thereby reducing the leachable lead content. The lead-based paint removal technology effectiveness was determined by the use of an X-ray fluorescence (XRF) spectrum analyzer (L- and K-shell). The effectiveness of the technologies to stabilize the debris was evaluated through the toxicity characteristic leaching procedure (TCLP). Wet abrasive blasting effectively removed the lead-based paint coating from both the wood and brick substrates to below the US Department of Housing and Urban Development Guideline (1mg/cm(2)) with no minimal or no damage to the underlying substrates (P<0.0001). The mean area air levels of lead-containing particulate generated during paint removal were significantly below the personal exposure limit (PEL) (P<0.0001). However, the mean personal breathing zone lead levels were approximately three times higher than the PEL. Neither of the two stabilization technologies consistently stabilized the resultant paint debris to achieve a leachable lead content below the RCRA regulatory threshold of <5 mg/l. PMID:11566404

  4. Immediate release tablets of telmisartan using superdisintegrant-formulation, evaluation and stability studies.

    PubMed

    Sekar, Vasanthakumar; Chellan, Vijaya Raghavan

    2008-04-01

    Telmisartan (anti-hypertensive) is insoluble in water; hence the drug may be slowly or incompletely dissolved in the gastro intestinal tract. So the rate of dissolution and therefore its bioavailability is less (bioavailability 42%). In the present study an attempt has been made to prepare immediate release tablets of telmisartan by using Polyplasdone XL-10 (Crosspovidone) at intragranular, extragranular and partly intra and extragranular level of addition to increase the rate of drug release from dosage form to increase the dissolution rate and hence its bioavailability. The prepared granules and tablets were evaluated for their physiochemical properties and in-vitro dissolution study was conducted for the prepared tablets. It was concluded that the immediate release tablets with proper hardness, disintegration time and with increase rate of dissolution can be made using Polyplasdone XL-10. Formuation-10 (F10) was selected for stability study and the in-vitro dissolution study showed that was no difference in percent of drug released between initial and sixth month sample. PMID:18379110

  5. Stability evaluation of the Panel 1 rooms and the E140 drift at WIPP

    SciTech Connect

    Maleki, H. [Maleki Technologies, Inc. (United States); Chaturvedi, L. [Environmental Evaluation Group, Albuquerque, NM (United States)

    1996-08-01

    WIPP, intended for underground permanent disposal of defense transuranic waste, is located 40 km east of Carlsbad at a depth of 655 m in the salt beds of the 600-m thick Permian Salado Formation. It will consist of 56 ``rooms`` each 91.5 m long, 10 m wide, and 4 m high, grouped in 8 ``panels`` of 7 rooms each. About 7.5 km of access drifts will also be provided. Excavation began in 1982 and surface/access/test facilities and one panel were completed by 1988, many years before it could be used. Current plans are to start emplacing waste in WIPP in 1998 and continue for 35 years. The north- south drift E140 is the widest (25 ft) of the four main north-south drifts and is the main north-south passage. Plans to conduct experiments with waste in 1993 were abandoned, and the plan now is to use panel 1 for permanent disposal of waste starting in 1998. The stability evaluation resulted in the conclusion that, while it would be possible to safely use portions of panel 1 for waste emplacement, it would be best to abandon panel 1 and mine a new panel after the decision has been made to use WIPP as a repository and the necessary permits obtained.

  6. Evaluating network analysis and agent based modeling for investigating the stability of commercial air carrier schedules

    NASA Astrophysics Data System (ADS)

    Conway, Sheila Ruth

    For a number of years, the United States Federal Government has been formulating the Next Generation Air Transportation System plans for National Airspace System improvement. These improvements attempt to address air transportation holistically, but often address individual improvements in one arena such as ground or in-flight equipment. In fact, air transportation system designers have had only limited success using traditional Operations Research and parametric modeling approaches in their analyses of innovative operations. They need a systemic methodology for modeling of safety-critical infrastructure that is comprehensive, objective, and sufficiently concrete, yet simple enough to be deployed with reasonable investment. The methodology must also be amenable to quantitative analysis so issues of system safety and stability can be rigorously addressed. The literature suggests that both agent-based models and network analysis techniques may be useful for complex system development and analysis. The purpose of this research is to evaluate these two techniques as applied to analysis of commercial air carrier schedule (route) stability in daily operations, an important component of air transportation. Airline-like routing strategies are used to educe essential elements of applying the method. Two main models are developed, one investigating the network properties of the route structure, the other an Agent-based approach. The two methods are used to predict system properties at a macro-level. These findings are compared to observed route network performance measured by adherence to a schedule to provide validation of the results. Those interested in complex system modeling are provided some indication as to when either or both of the techniques would be applicable. For aviation policy makers, the results point to a toolset capable of providing insight into the system behavior during the formative phases of development and transformation with relatively low investment. Both Agent-Based Modeling and Network Analysis were found to be useful in this context, particularly when applied with an eye towards the system context, and concentrated effort on capturing the salient features of the system of interest.

  7. Mixed voltage VLSI design

    NASA Technical Reports Server (NTRS)

    Panwar, Ramesh; Rennels, David; Alkalaj, Leon

    1993-01-01

    A technique for minimizing the power dissipated in a Very Large Scale Integration (VLSI) chip by lowering the operating voltage without any significant penalty in the chip throughput even though low voltage operation results in slower circuits. Since the overall throughput of a VLSI chip depends on the speed of the critical path(s) in the chip, it may be possible to sustain the throughput rates attained at higher voltages by operating the circuits in the critical path(s) with a high voltage while operating the other circuits with a lower voltage to minimize the power dissipation. The interface between the gates which operate at different voltages is crucial for low power dissipation since the interface may possibly have high static current dissipation thus negating the gains of the low voltage operation. The design of a voltage level translator which does the interface between the low voltage and high voltage circuits without any significant static dissipation is presented. Then, the results of the mixed voltage design using a greedy algorithm on three chips for various operating voltages are presented.

  8. The Stability of Teacher Performance and Effectiveness: Implications for Policies Concerning Teacher Evaluation

    ERIC Educational Resources Information Center

    Morgan, Grant B.; Hodge, Kari J.; Trepinski, Tonya M.; Anderson, Lorin W.

    2014-01-01

    The last five to ten years has seen a renewed interest in the stability of teacher behavior and effectiveness. Data on teacher performance and teacher effectiveness are being used increasingly as the basis for decisions about continued employment, tenure and promotion, and financial bonuses. The purpose of this study is to explore the stability of…

  9. Approach to evaluating dried blood spot sample stability during drying process and discovery of a treated card to maintain analyte stability by rapid on-card pH modification.

    PubMed

    Liu, Guowen; Ji, Qin C; Jemal, Mohammed; Tymiak, Adrienne A; Arnold, Mark E

    2011-12-01

    Unstable drug candidates often lead to complexity for both sample collection and bioanalysis. Dried blood spot (DBS) technology is believed to be a viable solution to address this problem. However, it is currently a challenge to evaluate compound stability on DBS due to its solid format. The observed compound loss on a DBS card could be degradation and/or incomplete recovery. Therefore, a reliable bioanalytical method which can differentiate recovery loss from degradation is necessary for such stability evaluation. In this paper, the stability of an unstable drug candidate (KAI-9803) in human blood was evaluated using DBS. A reliable approach to evaluating analyte stability on DBS was developed with an appropriate time-zero sample, a consistent DBS sample processing method, and a suitable positive control. Commercially available DBS cards were evaluated, and it was found that KAI-9803 degraded during the drying process. An in-house modified DBS card was developed and demonstrated to be able to stabilize KAI-9803 during the drying process by rapidly lowering the pH of the spotted blood sample. The storage stability of KAI-9803 in human blood on this new card has been established for at least 48 days at room temperature. This in-house modified DBS card could provide a generic approach for other compounds which require stabilization at a low pH. PMID:21995953

  10. Evaluation on Reduction of Output Suppression Loss by Cooperative Control of Voltage Profile in a Distribution System with a Large Amount of Photovoltaic Power Generation

    NASA Astrophysics Data System (ADS)

    Kondoh, Junji

    When large amounts of photovoltaic power generation systems (PV systems) are integrated into power distribution systems, voltage rise due to reverse power flow will be a great concern. Because the PV systems must restrict their output power in case of the voltage rise beyond the statutory upper limit. In order to improve this problem, the cooperative control of reactive power by the PV systems was proposed and the reduction of output suppression loss was estimated for a model distribution system. The result indicated that the output suppression loss is reduced to about 15% while line loss is increased a little, and the sum of the two losses is decreased by half.

  11. Technical evaluation of the proposed design modifications and technical specification changes on grid voltage degradation (Part A) for the Peach Bottom Atomic Power Station, Units 2 and 3: selected issues program (Docket Nos. 50-277, 50-278)

    SciTech Connect

    White, R. L.

    1981-11-03

    This report documents the technical evaluation of the proposed design modification and Technical Specification changes for protection of Class 1E equipment from grid voltage degradation for the Peach Bottom Atomic Power Station, Units 2 and 3. The review criteria are based on several IEEE standards and The Code of Federal Regulations. The evaluation compares the submittals made by the plant with the NRC staff positions and the review criteria. The licensee meets the requirements of the NRC except for the submittal of proposed Technical Specification changes to substantiate the proposed circuit modifications and relay setpoints.

  12. Development and evaluation of robust molecular markers linked to disease resistance in tomato for distinctness, uniformity and stability testing

    Microsoft Academic Search

    Paul Arens; Carmen Mansilla; Daniël Deinum; Laetitia Cavellini; André Moretti; Sophie Rolland; Hanneke van der Schoot; David Calvache; Fernando Ponz; Cécile Collonnier; René Mathis; Diederik Smilde; Carole Caranta; Ben Vosman

    2010-01-01

    Molecular markers linked to phenotypically important traits are of great interest especially when traits are difficult and\\/or\\u000a costly to be observed. In tomato where a strong focus on resistance breeding has led to the introgression of several resistance\\u000a genes, resistance traits have become important characteristics in distinctness, uniformity and stability (DUS) testing for\\u000a Plant Breeders Rights (PBR) applications. Evaluation of

  13. Interface connections of a transmembrane voltage sensor

    E-print Network

    White, Stephen

    -sensitive ion channels open and close in response to changes in transmembrane (TM) potential caused the membrane bilayer in response to TM voltage changes. Direct exposure of S4 sensors to lipid is contrary simulation of an isolated TM S4 helix in a lipid bilayer. The simulation reveals a stabilizing hydrogen

  14. Improving voltage disturbance rejection for variable-speed wind turbines

    Microsoft Academic Search

    Giuseppe Saccomando; Jan Svensson; Ambra Sannino

    2002-01-01

    In this paper, the effect of voltage dips on variable-speed wind turbines using voltage source converters (VSCs) is treated. Three different current controllers for the VSC are described and implemented. Their performance is evaluated when the converter is subject to different types of voltage dips. Both simulated and measured dips are used. The effect of the phase-angle jump of the

  15. Examination of Dynamic Drop Test Method for Evaluation of Hydrophobicity Stability of Polymeric Insulating Materials by CIGRE Round Robin Test

    NASA Astrophysics Data System (ADS)

    Homma, Hiroya; Nagao, Masayuki; Matsumoto, Takaie; Otsubo, Masahisa; Tokoro, Tetsuro

    To evaluate time variation of hydrophobicity of silicone rubbers used for outdoor polymeric insulators, various kinds of test methods have been suggested. CIGRE WG D1.14 conducted an international Round Robin Test (RRT) to clarify the efficiency and reproducibility of Dynamic Drop Test for the evaluation of hydrophobicity stability of the materials. Three Japanese universities were participated the RRT and had contributed much for the activity. This paper provides the outline of CIGRE RRT and typical experimental results of the Dynamic Drop test.

  16. Improving Low Voltage Ride Through Capability of Wind Generators Using Dynamic Voltage Restorer

    NASA Astrophysics Data System (ADS)

    Sivasankar, Gangatharan; Suresh Kumar, Velu

    2014-08-01

    The increasing wind power integration with power grid has forced the situation to improve the reliability of wind generators for stable operation. One important problem with induction generator based wind farm is its low ride through capability to the grid voltage disturbance. Any disturbance such as voltage dip may cause wind farm outages. Since wind power contribution is in predominant percentage, such outages may lead to stability problem. The proposed strategy is to use dynamic voltage controller (DVR) to compensate the voltage disturbance. The DVR provides the wind generator the ability to remain connected in grid and improve the reliability. The voltage dips due to symmetrical and unsymmetrical faults are considered for analysis. The vector control scheme is employed for fault compensation which uses software phase locked loop scheme and park dq0 transformation technique. Extensive simulation results are included to illustrate the control and operation of DVR.

  17. TECHNOLOGY EVALUATION REPORT: SITE PROGRAM DEMONSTRATION TEST, SOLIDITECH, INC. SOLIDIFICATION/STABILIZATION PROCESS VOL II

    EPA Science Inventory

    The primary objective of the Soliditech, Inc. solidification/stabilization demonstration was to develop reliable performance and cost information. he demonstration took palce at the Imperial Oil Company/Champion Chemical Company Superfund site in Morganiville, New Jersey. ontamin...

  18. TECHNOLOGY EVALUATION REPORT: SITE PROGRAM DEMONSTRATION TEST, SOLIDITECH, INC. SOLIDIFICATION/STABILIZATION PROCESS VOL I

    EPA Science Inventory

    The primary objective of the Soliditech, Inc. solidification/stabilization demonstration was to develop reliable performance and cost information. he demonstration took palce at the Imperial Oil Company/Champion Chemical Company Superfund site in Morganiville, New Jersey. Contami...

  19. Economic evaluation of flying-qualities design criteria for a transport configured with relaxed static stability

    NASA Technical Reports Server (NTRS)

    Sliwa, S. M.

    1980-01-01

    Direct constrained parameter optimization was used to optimally size a medium range transport for minimum direct operating cost. Several stability and control constraints were varied to study the sensitivity of the configuration to specifying the unaugmented flying qualities of transports designed to take maximum advantage of relaxed static stability augmentation systems. Additionally, a number of handling qualities related design constants were studied with respect to their impact on the design.

  20. Transient voltage dip analysis using the transient energy function method

    Microsoft Academic Search

    A. A. Fouad; Ramadevi Sreedhara

    1990-01-01

    It is shown that the transient energy function (TEF) method provides a fast approximate approach to voltage dip computations. The TEF method is used to predict the stability of a power system after a disturbance has occurred. The results of application of the technique to test power systems confirmed that the voltage dips predicted by the TEF method compare well

  1. Fault Current Limiter by Series Connected Voltage Source Inverter

    NASA Astrophysics Data System (ADS)

    Hojo, Masahide; Kuroe, Norihito; Ohnishi, Tokuo

    In recent years, various types of fault current limiter (FCL) have been developed, because installation of the FCL will bring a lot of benefits to power system operation. Power system controllers based on a concept of Flexible AC Transmission Systems (FACTS) can also be applicable as the FCL with growing power ratings of them. Such FCLs are expected to contribute power system stabilization or power quality enhancement in addition to fault current limitation. Authors have developed a new type of FCL, which consists of a series reactor and a self-commutated voltage source inverter connected in series with a power distribution line by a coupling transformer. In case of a system fault, the FCL will insert a sufficiently large inductance in series with the distribution line by both the series reactor and the inverter, then it will reduce the fault current. On the other hand, the inverter compensates a voltage drop across the series reactor in a standby mode. As a result, the FCL behaves like a negligible impedance in the standby mode. One of the distinctive features of the FCL is a simple configuration because its control strategy does not require an active power source. In addition, inverter voltage rating of the proposed FCL can be reduced by installing the series reactor as compared with other converter-based FCLs. The aim of this paper is to evaluate the operating characteristics of the FCL with both simulation and experimental studies.

  2. Evaluation of biological stability and corrosion potential in drinking water distribution systems: a case study.

    PubMed

    Chien, C C; Kao, C M; Chen, C W; Dong, C D; Chien, H Y

    2009-06-01

    The appearance of assimilable organic carbon (AOC), microbial regrowth, disinfection by-products (DBPs), and pipe corrosion in drinking water distribution systems are among those major safe drinking water issues in many countries. The water distribution system of Cheng-Ching Lake Water Treatment Plant (CCLWTP) was selected in this study to evaluate the: (1) fate and transport of AOC, DBPs [e.g., trihalomethanes (THMs), haloacetic acids (HAAs)], and other organic carbon indicators in the selected distribution system, (2) correlations between AOC (or DBPs) and major water quality parameters [e.g. dissolved oxygen (DO), free residual chlorine, and bacteria, and (3) causes and significance of corrosion problems of the water pipes in this system. In this study, seasonal water samples were collected from 13 representative locations in the distribution system for analyses of AOC, DBPs, and other water quality indicators. Results indicate that residual free chlorine concentrations in the distribution system met the drinking water standards (0.2 to 1 mg l(-1)) established by Taiwan Environmental Protection Administration (TEPA). Results show that AOC measurements correlated positively with total organic carbon (TOC) and UV-254 (an organic indicator) values in this system. Moreover, AOC concentrations at some locations were higher than the 50 microg acetate-C l(-1) standard established by Taiwan Water Company. This indicates that the microbial regrowth might be a potential water quality problem in this system. Higher DO measurements (>5.7 mg l(-1)) might cause the aerobic biodegradation of THMs and HAAs in the system, and thus, low THMs (<0.035 mg l(-1)) and HAAs (<0.019 mg l(-1)) concentrations were observed at all sampling locations. Results from the observed negative Langelier Saturation Index (LSI) values, higher Ryznar Stability Index (RSI) values, and high Fe3+ concentrations at some pipe-end locations indicate that highly oxidative and corrosive conditions occurred. This reveals that pipe replacement should be considered at these locations. These findings would be helpful in managing the water distribution system for maintaining a safe drinking water quality. PMID:18483769

  3. Enhanced cycling stability and rate performance of Li[Ni0.5Co0.2Mn0.3]O2 by CeO2 coating at high cut-off voltage

    NASA Astrophysics Data System (ADS)

    Liu, Kun; Yang, Gao-Li; Dong, Yue; Shi, Ting; Chen, Li

    2015-05-01

    A rough coating structure of CeO2@Li[Ni0.5Co0.2Mn0.3]O2 can be formed via a wet chemical method. X-ray diffraction (XRD), field-emission scanning electron microscope (FE-SEM) equipped with an energy dispersive spectroscope (EDS) are carried out to study the structures and morphologies, which all confirm the existence of CeO2 coating layer on the Li[Ni0.5Co0.2Mn0.3]O2 surface. The 2 wt.% CeO2-coated Li[Ni0.5Co0.2Mn0.3]O2 can deliver 97.4 mAh g-1 at 10 C and 59.2 mAh g-1 at 20 C after 100 cycles in the voltage range of 2.8-4.6 V, while the pristine Li[Ni0.5Co0.2Mn0.3]O2 can deliver only 23.5 mAh g-1 at 10 C and 9.0 mAh g-1 at 20 C. The discharge capacities of CeO2-coated Li[Ni0.5Co0.2Mn0.3]O2 samples at high discharge rates are much higher than those of the pristine Li[Ni0.5Co0.2Mn0.3]O2. Meanwhile, the CeO2-coated Li[Ni0.5Co0.2Mn0.3]O2 sample shows better rate performance at different rates. Electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV) measurements reveal that the improved electrochemical performance can be attributed to the reduced interfacial polarization and stabilized structure of Li[Ni0.5Co0.2Mn0.3]O2 by CeO2 coating. Transmission electron microscope (TEM) is applied to analyze the role of CeO2 coating layer on the long cycling life.

  4. Voltage Converter TYPICAL APPLICATION

    E-print Network

    Berns, Hans-Gerd

    s Inverting and Doubling Modes s Minimum Open Circuit Voltage Conversion Efficiency: 99% s Typical Power Voltage RL = 1k Inverter, LV = Open q 3 5.5 V Inverter, LV = GND q 1.5 5.5 V Doubler, LV = VOUT q 2.5 5 % Voltage Conversion Efficiency No Load 99 99.96 % Oscillator Sink or Source Current Boost = Open ±1.1 µ

  5. Direct subnanosecond voltage monitors

    SciTech Connect

    Barth, J.E.; Sajeant, W.J.

    1981-01-01

    Advanced system development in the subnanosecond time frame increasingly demands high-resolution voltage measurements for both single-shot and repetitive operation. Voltage monitors having capabilities up to the hundred kilovolt level have been developed for direct measurements in discrete and transmission line geometries. Resolutions of 100 ps at 100 kV to 30 ps at 20 kV have been achieved. Detailed test data is presented and ultimate voltage scaling limits are discussed.

  6. Evaluation of Need and Location for a Thermogravimetric Analyzer in the Plutonium Finishing Plant (PFP) Materials Stabilization

    SciTech Connect

    WILLIS, H.T.

    2000-01-20

    This plan provides an analysis for locating a TGA to support PFP Thermal Stabilization processes. The scope of this document is to evaluate the need for, and location for, installation of a TGA system as a supplement to the SFE equipment for moisture measurement in pure oxides. A location assessment for the SFE equipment was previously performed (HNF 1999). Based on that assessment, co-location of the TGA system with the SFE system is the preferred option. This would enable thermally stabilized material to be analyzed for residual moisture by either the TGA system or SFE system or both This evaluation considers glovebox locations in the PFP 234-52 Building Analytical Laboratory or operating areas for the installation of the TGA system and it's supporting equipment. This evaluation considers using existing gloveboxes along with an alternative of adding a new glovebox to existing process lines. The location evaluation criteria focuses mainly on glovebox size, with qualitative consideration of relative cost and schedule impacts associated with system implementation, radiological control, and interaction with other laboratory operations and processes. In addition, the possible co-location of a TGA furnace system with the SFE system was considered.

  7. Evaluation of carboxymethyl-beta-cyclodextrin with acid function: improvement of chemical stability, oral bioavailability and bitter taste of famotidine.

    PubMed

    Mady, Fatma M; Abou-Taleb, Ahmed E; Khaled, Khaled A; Yamasaki, Keishi; Iohara, Daisuke; Taguchi, Kazuaki; Anraku, Makoto; Hirayama, Fumitoshi; Uekama, Kaneto; Otagiri, Masaki

    2010-09-15

    The objective of the present study was to evaluate the potential influence of carboxymethyl-beta-cyclodextrin (CM-beta-CyD) on the aqueous solubility, chemical stability and oral bioavailability of famotidine (FMT) as well as on its bitter taste. We examined the effect of the CM-beta-CyD on the acidic degradation of FMT compared with that for sulfobutyl-ether-beta-cyclodextrin (SBE-beta-CyD). The potential use of CM-beta-CyD for orally disintegrating tablets (ODTs) was evaluated in vitro and in vivo. A taste perception study was also carried out. A strong stabilizing influence of CM-beta-CyD was observed against the acidic degradation, in sharp contrast to SBE-beta-CyD which induced a weird destabilizing effect on FMT. (13)C NMR was used to investigate the interaction mode between FMT and the 2 CyDs. In vivo study of ODTs indicated a significant increase in C(max), AUC and oral bioavailability in the case of FMT-CM-beta-CyD tablets, compared with plain drug tablets. However, no significant difference in T(max) and t(1/2) was observed. CM-beta-CyD complexation appears to be an acceptable strategy for enhancing the oral bioavailability of FMT owing to its dramatic effect on the aqueous solubility and chemical stability of the drug. In addition, it has a pronounced effect on masking the bitter taste of FMT. PMID:20600734

  8. Evaluation of miniature vacuum ultraviolet lamps for stability and operating characteristics, Lyman-Alpha task

    NASA Astrophysics Data System (ADS)

    Hurd, W. A.

    1985-01-01

    Modifications required to change the near ultraviolet source in the Optical Contamination Monitor to a source with output at or near the Lyman-Alpha hydrogen line are discussed. The effort consisted of selecting, acquiring and testing candidate miniature ultraviolet lamps with significant output in or near 121.6 nm. The effort also included selection of a miniature dc high-voltage power supply capable of operating the lamp. The power supply was required to operate from available primary power supplied by the Optical Effect Module (DEM) and it should be flight qualified or have the ability to be qualified by the user.

  9. Technical evaluation of the proposed design modifications and technical specification changes on grid voltage degradation (Part A) for the Rancho Seco Nuclear Generating Plant

    Microsoft Academic Search

    1980-01-01

    The Rancho Seco Nuclear Generating Plant has two 4160-volt and two 480-volt Class 1E buses. The existing undervoltage protection design uses a single undervoltage relay on each 4160-volt Class 1E bus. If the voltage drops below 3534 volts (85% of 4160 volts), the undervoltage relay will energize a set of load-shedding relays. The load-shedding relays initiate the disconnection of the

  10. Metastable Electrical Characteristics of Polycrystalline Thin-Film Photovoltaic Modules upon Exposure and Stabilization: Preprint

    Microsoft Academic Search

    C. A. Deline; J. A. del Cueto; D. S. Albin; S. R. Rummel

    2011-01-01

    The significant features of a series of stabilization experiments conducted at the National Renewable Energy Laboratory (NREL) between May 2009 and the present are reported. These experiments evaluated a procedure to stabilize the measured performance of thin-film polycrystalline cadmium telluride (CdTe) and copper indium gallium diselenide (CIGS) thin-film photovoltaic (PV) modules. The current-voltage (I-V) characteristics of CdTe and CIGS thin-film

  11. Technical evaluation of the proposed design modifications and technical specification changes on grid voltage degradation (Part A) for the Rancho Seco Nuclear Generating Plant

    SciTech Connect

    White, R.L.

    1980-10-01

    The Rancho Seco Nuclear Generating Plant has two 4160-volt and two 480-volt Class 1E buses. The existing undervoltage protection design uses a single undervoltage relay on each 4160-volt Class 1E bus. If the voltage drops below 3534 volts (85% of 4160 volts), the undervoltage relay will energize a set of load-shedding relays. The load-shedding relays initiate the disconnection of the emergency 4160-volt buses from the off-site source, load shed the emergency 4160-volt buses, start the emergency diesel generators, and provide an enabling signal for the load-sequencing timing circuit. When the emergency diesel generator reaches the required voltage it is connected to the emergency buses and load-sequencing will begin automatically, if a safety injection (SI) signal exists. The licensee has proposed a design change to establish an automatic degraded voltage protection circuitry. The modification consists of incorporating the existing undervoltage protection scheme will consist of 3 undervoltage relays monitoring each 4160-volt emergency bus. The 3 undervoltage relays will be arranged in a 2-out-of-3 coincident logic with a setpoint of 3771 volts +- 38 volts (90.6% of 4160 volts) with a time delay of 12 seconds +- 1.2 seconds.

  12. Evaluation of the threshold of stability for the human spine Martin L. Tanaka a,b,d,, Maury A. Nussbaum b,c

    E-print Network

    Ross, Shane

    Evaluation of the threshold of stability for the human spine Martin L. Tanaka a,b,d,Ã?, Maury A of the spine, paraspinal ligaments, core musculature, and neuro- muscular control system to maintain an upright

  13. Off-set stabilizer for comparator output

    DOEpatents

    Lunsford, James S. (Los Alamos, NM)

    1991-01-01

    A stabilized off-set voltage is input as the reference voltage to a comparator. In application to a time-interval meter, the comparator output generates a timing interval which is independent of drift in the initial voltage across the timing capacitor. A precision resistor and operational amplifier charge a capacitor to a voltage which is precisely offset from the initial voltage. The capacitance of the reference capacitor is selected so that substantially no voltage drop is obtained in the reference voltage applied to the comparator during the interval to be measured.

  14. Synthesis of Macrocyclic Hexaoxazole (6OTD) Dimers, Containing Guanidine and Amine Functionalized Side Chains, and an Evaluation of Their Telomeric G4 Stabilizing Properties

    PubMed Central

    Iida, Keisuke; Tera, Masayuki; Hirokawa, Takatsugu; Shin-ya, Kazuo; Nagasawa, Kazuo

    2010-01-01

    Structure-activity relationship studies were carried out on macrocyclic hexaoxazole (6OTD) dimers, whose core structure stabilizes telomeric G-quadruplexes (G4). Two new 6OTD dimers having side chain amine and guanidine functional groups were synthesized and evaluated for their stabilizing ability against a telomeric G4 DNA sequence. The results show that the 6OTD dimers interact with the DNA to form 1:1 complexes and stabilize the antiparallel G4 structure of DNA in the presence of potassium cation. The guanidine functionalized dimer displays a potent stabilizing ability of the G4 structure, as determined by using a FRET melting assay (?Tm = 14°C). PMID:20700415

  15. Simplified method for evaluating the flight stability of liquid-filled projectiles

    Microsoft Academic Search

    Daniel J. Weber

    1994-01-01

    This paper describes a modification to the tricyclic theory to include the effect of a liquid payload on the motion and stability of the projectile. The influence on the projectile's motion by the liquid payload is similar to the Magnus effect. A computer program has been developed that determines the complex projectile motion using either theoretical estimates of liquid-fill characteristics

  16. Development and flight evaluation of an augmented stability active controls concept: Executive summary

    NASA Technical Reports Server (NTRS)

    Guinn, W. A.

    1982-01-01

    A pitch active control system (PACS) was developed and flight tested on a wide body jet transport (L-1011) with a flying horizontal stabilizer. Two dual channel digital computers and the associated software provide command signals to a dual channel series servo which controls the stabilizer power actuators. Input sensor signals to the computer are pitch rate, column trim position, and dynamic pressure. Control laws are given for the PACS and the system architecture is defined. Discussions are given regarding piloted flight simulation and vehicle system simulation and vehicle system simulation tests that are performed to verify control laws and system operation prior to installation on the aircraft. Modifications to the basic aircraft included installation of the PACS, addition of a c.g. management system to provide a c.g. range from 25 to 39% mac, and downrigging of the geared elevator to provide the required nose down control authority for aft c.g. flight test conditions. Three pilots used the Cooper-Harper Rating Scale to judge flying qualities of the aircraft with PACS on and off. The handling qualities with the c.g. at 39% mac (41% stability margin) and PACS operating were judged to be as good as the handling qualities with the c.g. at 25% mac (+15% stability margin) and PACS off.

  17. Quantitative evaluation of transient heat transfer on axial flow compressor stability

    Microsoft Academic Search

    R. A. Crawford; A. E. Burwell

    1985-01-01

    An essential factor for acceptable engine performance and safety in the case of an aircraft gas turbine engine is the stable operation of the compression system. A number of basic research programs were conducted to investigate the influence of transient heat transfer effects on axial flow compressor stability. The results of these programs led to the conclusion that sound theoretical

  18. An Outcome Evaluation of an Inpatient Crisis Stabilization and Assessment Program for Youth

    ERIC Educational Resources Information Center

    Greenham, Stephanie L.; Bisnaire, Lise

    2008-01-01

    Objective: To describe characteristics and outcomes of youth aged 7 to 17 who received inpatient psychiatric and mental health services along different clinical pathways of a new service delivery model. Method: Participants included 211 admissions to an inpatient crisis stabilization and assessment program over a one-year period. Standardized…

  19. Superfund Innovative Technology Evaluation - Demonstration Bulletin: In-Situ Soil Stabilization

    EPA Science Inventory

    In-situ stabilization technology immobilizes organics and inorganic compounds in wet or dry soils by using reagents (additives) to polymerize with the soils and sludges producing a cement-like mass. Two basic components of this technology are the Geo-Con/DSM Deep Soil Mixing Sy...

  20. Thermal stability of epoxy resins containing flame retardant components: an evaluation with thermogravimetric analysis

    Microsoft Academic Search

    Chuan Shao Wu; Ying Ling Liu; Yie Chan Chiu; Yie Shun Chiu

    2002-01-01

    The thermal properties of epoxy resins containing flame retardants based on silicon, phosphorus, and melamine, were investigated with thermogravimetric analysis (TGA). The weight loss behaviour (including the weight loss temperatures, weight loss rates, and the activation energy for each weight loss stage) and the thermal stability (including the initial decomposition temperature and integral procedure decomposition temperature) were characterized. Phosphorus groups

  1. Evaluation of Alpha-Phased Zirconium Phosphate Nanoparticles as a Clay Stabilizer and an EOR Agent

    E-print Network

    Zhou, Yi

    2014-12-15

    oil after secondary recovery. Nanoparticles are used as clay stabilizers and EOR agent because of their very small size, large surface area, and surface electrical charge. In this paper, an ?-ZrP nanoparticle-based treatment is developed to prevent...

  2. Battery voltage regulation system

    Microsoft Academic Search

    N. Mayumi; H. Kato; H. Matsuhashi

    1986-01-01

    A battery voltage regulating system is described for an automotive vehicle having a battery, an alternator driven by an internal combustion engine mounted on the vehicle and generating an alternating current, and a full-wave rectifier for rectifying the alternating current to charge the battery. The system consists of: an operational amplifier connected to the battery for comparing a battery voltage

  3. Cascaded voltage collapse

    SciTech Connect

    Sekine, Y. (Tokyo Univ. (Japan)); Ohtsuki, H. (Kansai Electric Power Co., Inc., Osaka (Japan))

    1990-02-01

    The dynamic phenomena of voltage collapse are analyzed by the method of dynamic simulation using induction motor models. From the view point of dynamic phenomena, the voltage collapse starts locally at the weakest node and spreads out to the other weak nodes.

  4. Voltage verification unit

    DOEpatents

    Martin, Edward J. (Virginia Beach, VA)

    2008-01-15

    A voltage verification unit and method for determining the absence of potentially dangerous potentials within a power supply enclosure without Mode 2 work is disclosed. With this device and method, a qualified worker, following a relatively simple protocol that involves a function test (hot, cold, hot) of the voltage verification unit before Lock Out/Tag Out and, and once the Lock Out/Tag Out is completed, testing or "trying" by simply reading a display on the voltage verification unit can be accomplished without exposure of the operator to the interior of the voltage supply enclosure. According to a preferred embodiment, the voltage verification unit includes test leads to allow diagnostics with other meters, without the necessity of accessing potentially dangerous bus bars or the like.

  5. Application of matrix singular value properties for evaluating gain and phase margins of multiloop systems. [stability margins for wing flutter suppression and drone lateral attitude control

    NASA Technical Reports Server (NTRS)

    Mukhopadhyay, V.; Newsom, J. R.

    1982-01-01

    A stability margin evaluation method in terms of simultaneous gain and phase changes in all loops of a multiloop system is presented. A universal gain-phase margin evaluation diagram is constructed by generalizing an existing method using matrix singular value properties. Using this diagram and computing the minimum singular value of the system return difference matrix over the operating frequency range, regions of guaranteed stability margins can be obtained. Singular values are computed for a wing flutter suppression and a drone lateral attitude control problem. The numerical results indicate that this method predicts quite conservative stability margins. In the second example if the eigenvalue magnitude is used instead of the singular value, as a measure of nearness to singularity, more realistic stability margins are obtained. However, this relaxed measure generally cannot guarantee global stability.

  6. Voltage-dependent gating of HERG potassium channels.

    PubMed

    Cheng, Yen May; Claydon, Tom W

    2012-01-01

    The mechanisms by which voltage-gated channels sense changes in membrane voltage and energetically couple this with opening of the ion conducting pore has been the source of significant interest. In voltage-gated potassium (Kv) channels, much of our knowledge in this area comes from Shaker-type channels, for which voltage-dependent gating is quite rapid. In these channels, activation and deactivation are associated with rapid reconfiguration of the voltage-sensing domain unit that is electromechanically coupled, via the S4-S5 linker helix, to the rate-limiting opening of an intracellular pore gate. However, fast voltage-dependent gating kinetics are not typical of all Kv channels, such as Kv11.1 (human ether-à-go-go related gene, hERG), which activates and deactivates very slowly. Compared to Shaker channels, our understanding of the mechanisms underlying slow hERG gating is much poorer. Here, we present a comparative review of the structure-function relationships underlying activation and deactivation gating in Shaker and hERG channels, with a focus on the roles of the voltage-sensing domain and the S4-S5 linker that couples voltage sensor movements to the pore. Measurements of gating current kinetics and fluorimetric analysis of voltage sensor movement are consistent with models suggesting that the hERG activation pathway contains a voltage independent step, which limits voltage sensor transitions. Constraints upon hERG voltage sensor movement may result from loose packing of the S4 helices and additional intra-voltage sensor counter-charge interactions. More recent data suggest that key amino acid differences in the hERG voltage-sensing unit and S4-S5 linker, relative to fast activating Shaker-type Kv channels, may also contribute to the increased stability of the resting state of the voltage sensor. PMID:22586397

  7. Low voltage to high voltage level shifter and related methods

    NASA Technical Reports Server (NTRS)

    Mentze, Erik J. (Inventor); Hess, Herbert L. (Inventor); Buck, Kevin M. (Inventor); Cox, David F. (Inventor)

    2006-01-01

    A shifter circuit comprises a high and low voltage buffer stages and an output buffer stage. The high voltage buffer stage comprises multiple transistors arranged in a transistor stack having a plurality of intermediate nodes connecting individual transistors along the stack. The transistor stack is connected between a voltage level being shifted to and an input voltage. An inverter of this stage comprises multiple inputs and an output. Inverter inputs are connected to a respective intermediate node of the transistor stack. The low voltage buffer stage has an input connected to the input voltage and an output, and is operably connected to the high voltage buffer stage. The low voltage buffer stage is connected between a voltage level being shifted away from and a lower voltage. The output buffer stage is driven by the outputs of the high voltage buffer stage inverter and the low voltage buffer stage.

  8. Single Event Transients in Low Voltage Dropout (LVDO) Voltage Regulators

    NASA Technical Reports Server (NTRS)

    LaBel, K.; Karsh, J.; Pursley, S.; Kleyner, I.; Katz, R.; Poivey, C.; Kim, H.; Seidleck, C.

    2006-01-01

    This viewgraph presentation reviews the use of Low Voltage Dropout (LVDO) Voltage Regulators in environments where heavy ion induced Single Event Transients are a concern to the designers.Included in the presentation are results of tests of voltage regulators.

  9. Performance evaluation of cement stabilized fly ash-GBFS mixes as a highway construction material.

    PubMed

    Singh, S P; Tripathy, D P; Ranjith, P G

    2008-01-01

    Fly ash and granulated blast furnace slag (GBFS) are major by-products of thermal and steel plants, respectively. These materials often cause disposal problems and environmental pollution. Detailed laboratory investigations were carried out on cement stabilized fly ash-(GBFS) mixes in order to find out its suitability for road embankments, and for base and sub-base courses of highway pavements. Proctor compaction test, unconfined compressive strength (UCS) test and California Bearing Ratio (CBR) test were conducted on cement stabilized fly ash-GBFS mixes as per the Indian Standard Code of Practice. Cement content in the mix was varied from 0% to 8% at 2% intervals, whereas the slag content was varied as 0%, 10%, 20%, 30% and 40%. Test results show that an increase of either cement or GBFS content in the mixture, results in increase of maximum dry density (MDD) and decrease of optimum moisture content (OMC) of the compacted mixture. The MDD of the cement stabilized fly ash-GBFS mixture is comparably lower than that of similarly graded natural inorganic soil of sand to silt size. This is advantageous in constructing lightweight embankments over soft, compressible soils. An increase in percentage of cement in the fly ash-GBFS mix increases enormously the CBR value. Also an increase of the amount of GBFS in the fly ash sample with fixed cement content improves the CBR value of the stabilized mix. In the present study, the maximum CBR value of compacted fly ash-GBFS-cement (52:40:8) mixture obtained was 105%, indicating its suitability for use in base and sub-base courses in highway pavements with proper combinations of raw materials. PMID:18060762

  10. Chemical evaluation and storage stability of a beverage formulated from soybean and papaya pulp flour blends

    Microsoft Academic Search

    M. U. Ukwuru; A. Adama

    2003-01-01

    Flour blends [soyflour (SF): papaya pulp flour (PF) 100:0, 70:30, 50:50, 30:70, 0:100] were prepared from soybean and papaya pulp flours. The blends were fortified with vitamin C. The chemical compositions and sensory characteristics of the soybean flour (SF), papaya pulp flour (PF) and their blends were determined. Storage stabilities of the most accepted blends were determined. The SF contained

  11. First-year evaluation of low-level waste-management stabilization techniques

    Microsoft Academic Search

    Cox

    1981-01-01

    The first year of observation for effectiveness of biobarriers and herbicides in revegetation efforts demonstrated that certain practices will result in successful site stabilization: proper orientation of burial trench to reduce erosion; utilization of mulches to conserve moisture; seeding mixed perennial or annual grass species at the proper time for optimization of establishment and growth; and applying 2,4-D amine\\/Dicamba selective

  12. Characterization and stability evaluation of ?-carotene nanoemulsions prepared by high pressure homogenization under various emulsifying conditions

    Microsoft Academic Search

    Yuan Yuan; Yanxiang Gao; Jian Zhao; Like Mao

    2008-01-01

    In this study, oil-in-water nanoemulsions of ?-carotene were produced by high pressure homogenization. The influence of emulsifying conditions including emulsifier type and concentration, homogenization pressure, temperature and cycle on the properties and stability of the nanoemulsions were investigated using a Zetasizer and a Turbiscan Lab, respectively. The mean diameters (z-average) of the dispersed particles containing ?-carotene ranged from 132 to

  13. Damp heat stability of chalcopyrite mini-modules: evaluation of specific test structures

    Microsoft Academic Search

    Joachim Klaer; Reiner Klenk; Axel Boden; Axel Neisser; Christian Kaufmann; Roland Scheer; Hans-Werner Schock

    2005-01-01

    Damp heat stress (85% relative humidity at 85°C) has been used to test long term stability of CIS thin film photovoltaic devices. Two CIS absorber types have been examined, CuInS2 and Cu(In,Ga)Se2. Module degradation is dominated by an increase of the series resistance Rs. In order to get information about the ZnO sheet resistance Rsq and the Mo\\/ZnO contact resistance

  14. Evaluation of load transfer characteristics of a dynamic stabilization device on disc loading under compression

    Microsoft Academic Search

    Qing Hang Zhang; Yuan Li Zhou; Dominique Petit; Ee Chon Teo

    2009-01-01

    In the current study, finite element analyses were conducted to examine the biomechanical capability of a newly design dynamic stabilization system, FlexPLUS, to restore the load transmission of degenerated intervertebral L4-L5 lumbar motion segment spine under compression. Detailed three-dimensional FE models of L4-L5 motion segment and the FlexPLUS were developed. Compressive loading up to 1000N was applied to the intact

  15. Impaction grafted bone chip size effect on initial stability in an acetabular model: Mechanical evaluation

    PubMed Central

    Holton, Colin; Bobak, Peter; Wilcox, Ruth; Jin, Zhongmin

    2013-01-01

    Introduction Acetabular bone defect reconstruction is an increasing problem for surgeons with patients undergoing complex primary or revision total hip replacement surgery. Impaction bone grafting is one technique that has favourable long-term clinical outcome results for patients who undergo this reconstruction method for acetabular bone defects. Creating initial mechanical stability of the impaction bone graft in this technique is known to be the key factor in achieving a favourable implant survival rate. Different sizes of bone chips were used in this technique to investigate if the size of bone chips used affected initial mechanical stability of a reconstructed acetabulum. Methodology Twenty acetabular models were created in total. Five control models were created with a cemented cup in a normal acetabulum. Then five models in three different groups of bone chip size were constructed. The three groups had an acetabular protrusion defect reconstructed using either; 2–4 mm3, 10 mm3 or 20 mm3 bone chip size for impaction grafting reconstruction. The models underwent compression loading up to 9500 N and displacement within the acetabular model was measured indicating the initial mechanical stability. Results This study reveals that, although not statistically significant, the largest (20 mm3) bone chip size grafted models have an inferior maximum stiffness compared to the medium (10 mm3) bone chip size. Interpretations Our study suggests that 10 mm3 size of bone chips provide better initial mechanical stability compared to smaller or larger bone chips. We dismissed the previously held opinion that the biggest practically possible graft is best for acetabular bone graft impaction. PMID:24396238

  16. Use of different techniques in the evaluation of the oxidative stability of poultry fat biodiesel

    Microsoft Academic Search

    E. F. S. M. Ramalho; A. R. Albuquerque; A. L. Souza; A. K. Barro; A. S. Maia; I. M. G. Santos; A. G. Souza

    The poultry fat methylic (BMF) and ethylic (BEF) biodiesels were synthesized through transesterification by homogeneous basic\\u000a catalysis. The chromatographic analyses showed the palmitic, stearic, oleic, and linoleic esters as majority components. Owing\\u000a to its considerable amount of polyunsaturated fat acids, poultry fat usually leads to a biodiesel with low oxidative stability.\\u000a In this study, the oxidation of their ethylic and

  17. Evaluation of Mask Soaking Performance in a Thermally Stabilized Vacuum Chamber in an Electron Beam Mask Writer

    NASA Astrophysics Data System (ADS)

    Mitsui, Soichiro; Akeno, Kiminobu; Ogasawara, Munehiro; Tojo, Toru

    2004-06-01

    A temperature difference between a mask and a writing environment, which occurs during mask loading, is one of the most significant sources of the mask image placement error. The temperature of the mask has to be adjusted in a thermal chamber. To realize a rapid and highly accurate thermal soaking process, we constructed a new thermally stabilized vacuum chamber with an improved thermal soaking efficiency and evaluated its performance. The chamber is equipped with the top and bottom thermal stabilization plates (TSPs). It was found that the soaking time is largely dependent on the emissivities of the TSPs. The soaking relaxation time of less than 0.4 h is achieved. The thermal stability of the mask after soaking is 0.004°C (3?) for 12 h. It was also found that a high TSP emissivity is effective in reducing the influence of the temperature variation of the environment on the mask, and the temperature variation of the mask is reduced to approximately 28% of that of the environment. A quick soaking and stable temperature holding of the mask are realized.

  18. Application of maltodextrin and gum Arabic in microencapsulation of saffron petal's anthocyanins and evaluating their storage stability and color.

    PubMed

    Mahdavee Khazaei, K; Jafari, S M; Ghorbani, M; Hemmati Kakhki, A

    2014-05-25

    In this work, anthocyanin stability and color of encapsulated freeze-dried saffron petal's extract with various matrices consisting gum Arabic (AG) and maltodextrin (M7 and M20) were studied. Total anthocyanins of powders and color parameters (a*, b*, L*, C, H° and TCD) were measured immediately after production and during storage up to 10 weeks by pH differential method and computer vision, respectively. Different compounds of wall materials did not show any significant differences in terms of stabilizing anthocyanins (P<0.01) and no significant decrease in anthocyanin content of the powders was observed after storage. The efficiency order of wall materials considering total color differences (TCD) was AG>M20>M7. By evaluating 3D surface and Cox trace plots it was revealed that wall formulas which had the lowest amount of AG and highest amounts of M20 and M7 showed the lowest total color differences after storage (P<0.05). To conclude, microencapsulation by freeze drying could be recommended as a suitable method for stabilizing anthocyanins of saffron petal's extract. PMID:24708952

  19. Optimization of microwave-assisted extraction of cottonseed oil and evaluation of its oxidative stability and physicochemical properties.

    PubMed

    Taghvaei, Mostafa; Jafari, Seid Mahdi; Assadpoor, Elham; Nowrouzieh, Shahram; Alishah, Omran

    2014-10-01

    Microwave assisted extraction (MAE) is a novel method, which can reduce the extraction time and solvent consumption. This study aimed to evaluate the influence of MAE on oxidative stability and physicochemical properties of cottonseed oil. We found that the optimum extraction conditions were: irradiation time 3.57 min; cottonseed moisture content 14% and cottonseed to solvent ratio 1:4, which resulted in an extraction efficiency of 32.6%, 46 ppm total phenolic content, 0.7% free fatty acids, peroxide value of 0.2 and 11.5 h of Rancimat oxidative stability at 110 °C. GC analysis for MAE cottonseed oil determined palmitic acid (23.6%), stearic acid (2.3%), oleic acid (15.6%) and linoleic acid (55.1%), which were not significant different (P>0.05) than conventionally-extracted (control) cottonseed oil. MAE oil samples from whole cottonseed (without dehulling) had the greatest long-term stability, more than oil samples containing BHT. PMID:24799213

  20. VOLTAGE SECURITY ENHANCEMENT AND CONGESTION MANAGEMENT VIA STATCOM & IPFC USING ARTIFICIAL INTELLIGENCE

    Microsoft Academic Search

    A. KARAMI; M. RASHIDINEJAD; A. A. GHARAVEISI

    2007-01-01

    Voltage security and congestion management are crucial issues in power systems, especially under heavily loaded conditions. In the new scheme of electricity restructuring, voltage security problems become even more serious. Due to the increase in stability margins, FACTS devices are the best option to mitigate voltage instability by reactive power management. The main purpose of this paper is to identify

  1. Low voltage and high transmittance blue-phase liquid crystal displays with corrugated electrodes

    E-print Network

    Wu, Shin-Tson

    Low voltage and high transmittance blue-phase liquid crystal displays with corrugated electrodes January 2010 A low voltage 10 V and high transmittance 85.6% polymer-stabilized blue-phase liquid crystal along the beam path is large, resulting in low voltage and high transmittance. This approach enables

  2. Evaluation of metabolically stabilized angiotensin IV analogs as procognitive/antidementia agents.

    PubMed

    McCoy, Alene T; Benoist, Caroline C; Wright, John W; Kawas, Leen H; Bule-Ghogare, Jyote M; Zhu, Mingyan; Appleyard, Suzanne M; Wayman, Gary A; Harding, Joseph W

    2013-01-01

    Angiotensin IV (AngIV: VYIHPF)-related peptides have long been recognized as procognitive agents with potential as antidementia therapeutics. Their development as useful therapeutics, however, has been limited by physiochemical properties that make them susceptible to metabolic degradation and impermeable to gut and blood-brain barriers. A previous study demonstrated that the core structural information required to impart the procognitive activity of the AngIV analog, norleucine(1)-angiotensin IV, resides in its three N-terminal amino acids, Nle-Tyr-Ile. The goal of this project was to chemically modify this tripeptide in such a way to enhance its metabolic stability and barrier permeability to produce a drug candidate with potential clinical utility. Initial results demonstrated that several N- and C-terminal modifications lead to dramatically improved stability while maintaining the capability to reverse scopolamine-induced deficits in Morris water maze performance and augment hippocampal synaptogenesis. Subsequent chemical modifications, which were designed to increase hydrophobicity and decrease hydrogen bonding, yielded an orally active, blood-barrier permeant, metabolically stabilized analog, N-hexanoic-Tyr-Ile-(6) aminohexanoic amide (dihexa), that exhibits excellent antidementia activity in the scopolamine and aged rat models and marked synaptogenic activity. These data suggest that dihexa may have therapeutic potential as a treatment of disorders, such as Alzheimer's disease, where augmented synaptic connectivity may be beneficial. PMID:23055539

  3. Iron hydroxy carbonate formation in zerovalent iron permeable reactive barriers: characterization and evaluation of phase stability.

    PubMed

    Lee, Tony R; Wilkin, Richard T

    2010-07-30

    Predicting the long-term potential of permeable reactive barriers for treating contaminated groundwater relies on understanding the endpoints of biogeochemical reactions between influent groundwater and the reactive medium. Iron hydroxy carbonate (chukanovite) is frequently observed as a secondary mineral precipitate in granular iron PRBs. Mineralogical characterization was carried out using X-ray diffraction, scanning electron microscopy, thermogravimetric analysis, and X-ray absorption spectroscopy on materials collected from three field-based PRBs in the US (East Helena, MT; Elizabeth City, NC; Denver Federal Center, CO). These PRBs were installed to treat a range of contaminants, including chlorinated organics, hexavalent chromium, and arsenic. Results obtained indicate that chukanovite is a prevalent secondary precipitate in the PRBs. Laboratory experiments on high-purity chukanovite separates were carried out to constrain the room-temperature solubility for this mineral. An estimated Gibbs energy of formation (Delta(f)G degrees) for chukanovite is -1174.4 +/- 6 kJ/mol. A mineral stability diagram is consistent with observations from the field. Water chemistry from the three reactive barriers falls inside the predicted stability field for chukanovite, at inorganic carbon concentrations intermediate to the stability fields of siderite and ferrous hydroxide. These new data will aid in developing better predictive models of mineral accumulation in zerovalent iron PRBs. PMID:20554346

  4. Evaluation of Metabolically Stabilized Angiotensin IV Analogs as Procognitive/Antidementia Agents

    PubMed Central

    McCoy, Alene T.; Benoist, Caroline C.; Wright, John W.; Kawas, Leen H.; Bule-Ghogare, Jyote M.; Zhu, Mingyan; Appleyard, Suzanne M.; Wayman, Gary A.

    2013-01-01

    Angiotensin IV (AngIV: VYIHPF)–related peptides have long been recognized as procognitive agents with potential as antidementia therapeutics. Their development as useful therapeutics, however, has been limited by physiochemical properties that make them susceptible to metabolic degradation and impermeable to gut and blood-brain barriers. A previous study demonstrated that the core structural information required to impart the procognitive activity of the AngIV analog, norleucine1-angiotensin IV, resides in its three N-terminal amino acids, Nle-Tyr-Ile. The goal of this project was to chemically modify this tripeptide in such a way to enhance its metabolic stability and barrier permeability to produce a drug candidate with potential clinical utility. Initial results demonstrated that several N- and C-terminal modifications lead to dramatically improved stability while maintaining the capability to reverse scopolamine-induced deficits in Morris water maze performance and augment hippocampal synaptogenesis. Subsequent chemical modifications, which were designed to increase hydrophobicity and decrease hydrogen bonding, yielded an orally active, blood-barrier permeant, metabolically stabilized analog, N-hexanoic-Tyr-Ile-(6) aminohexanoic amide (dihexa), that exhibits excellent antidementia activity in the scopolamine and aged rat models and marked synaptogenic activity. These data suggest that dihexa may have therapeutic potential as a treatment of disorders, such as Alzheimer’s disease, where augmented synaptic connectivity may be beneficial. PMID:23055539

  5. Voltage regulation in distribution networks with distributed generation

    NASA Astrophysics Data System (ADS)

    Blaži?, B.; Uljani?, B.; Papi?, I.

    2012-11-01

    The paper deals with the topic of voltage regulation in distribution networks with relatively high distributed energy resources (DER) penetration. The problem of voltage rise is described and different options for voltage regulation are given. The influence of DER on voltage profile and the effectiveness of the investigated solutions are evaluated by means of simulation in DIgSILENT. The simulated network is an actual distribution network in Slovenia with a relatively high penetration of distributed generation. Recommendations for voltage control in networks with DER penetration are given at the end.

  6. Generating Electrical Voltage

    NSDL National Science Digital Library

    Teachers' Domain presents this interactive lesson designed to help students "learn how a generator converts mechanical energy into electrical energy. Investigate the principle of magnetic induction by moving a conductor through a magnetic field to see how voltage is generated." The lesson is divided into three major sections: How Do Generators Work?, What Factors Influence Voltage Strength?, and What Determines Voltage Polarity? There are plenty of animations to help students visualize the processes at work in electricity generation. On the site, visitors will also find a supplemental background essay, discussion questions, and standards alignment from Teachers' Domain.

  7. Long-term stability of dye solar cells

    Microsoft Academic Search

    Ravi Harikisun; Hans Desilvestro

    2011-01-01

    This work provides a review of dye solar cell long-term stability under light and thermal stress factors as well as discussion on the main degradation mechanisms. Performance and EIS parameters of industrial type Z907-based cells were evaluated during the course of continuous light soaking over 25,600h at 55–60°C. Only minor degradation occurred under such conditions, with open circuit voltages dropping

  8. Radon as a tool for characterising atmospheric stability effects on air pollution concentrations in model evaluation studies

    NASA Astrophysics Data System (ADS)

    Chambers, Scott; Williams, Alastair; Crawford, Jagoda; Griffiths, Alan

    2015-04-01

    A clearer understanding of the variability in near-surface concentrations of pollutants in urban regions is essential for improving the predictive abilities of chemical transport models as well as identifying the need for (and assessing the efficacy of) emission mitigation strategies. Pollutant concentrations in the atmospheric boundary layer (ABL) are a complex function of many factors, including: source strengths and distribution, local meteorology and air chemistry. On short (sub-diurnal) timescales, the extent of the vertical column within which emissions mix usually has the largest influence on measured concentrations, and the depth of this mixing volume is in turn closely related to wind speed and the thermal stability of the ABL. Continuous hourly observations of the ubiquitous, surface-emitted, passive tracer radon-222 provide a powerful alternative to contemporary meteorological techniques for assessing stability effects on urban pollutants, because radon's concentration is closely matched with pollution transport processes at the surface. Here we outline a technique by which single-height, near-surface (<20m) radon observations can be conditioned to derive a multi-category stability classification scheme for urban pollution monitoring to provide benchmarking tools for local- to regional- chemical transport model evaluations. Efficacy of the radon-based classification scheme is compared to that based on conventional Pasquil-Gifford "turbulence" and "radiation" schemes. Lastly, we apply the radon-based classification scheme to nocturnal mixing height estimates calculated from the diurnal radon accumulation time series, and provide insight to the range of nocturnal mixing depths expected for each of the stability classes.

  9. Homogeneity and stability of materials distributed within the wageningen evaluating programmes for analytical laboratories

    Microsoft Academic Search

    D. van Dijk; V. J. G. Houba

    2000-01-01

    Participation in laboratory evaluating programmes (Proficiency Testing schemes) is becoming increasingly important, especially for accredited laboratories. The Wageningen Agricultural University meets this need by organizing several world?wide international laboratory evaluating programmes on chemical analysis of soils (ISE), plants OPE), manure, refuses (MARSEP) and sediments (SETOC). Since 1995, the existing programmes have been placed under an umbrella organization called WEPAL: Wageningen

  10. Threshold voltage extraction circuit 

    E-print Network

    Hoon, Siew Kuok

    2000-01-01

    A novel optimally self-biasing MOSFET threshold-voltage (V[]) extractor circuit is presented. It implements the most popular industrial extraction algorithm of biasing a saturated MOSFET to the linear portion of its [] versus [] characteristic...

  11. Improving membrane voltage measurements

    E-print Network

    Cai, Long

    as fluorescence resonance energy transfer (FRET) donor and acceptor to develop a voltage sensor, named Mermaid activities in cultured excitable cells. Notably, Mermaid has fast on-off kinetics at warm (B33 1C

  12. Threshold voltage extraction circuit

    E-print Network

    Hoon, Siew Kuok

    2000-01-01

    A novel optimally self-biasing MOSFET threshold-voltage (V[]) extractor circuit is presented. It implements the most popular industrial extraction algorithm of biasing a saturated MOSFET to the linear portion of its [] versus [] characteristic...

  13. Organic solar cells: evaluation of the stability of P3HT using time-delayed degradation

    NASA Astrophysics Data System (ADS)

    Poh, Chung-How; Poh, Chung-Kiak; Bryant, Glenn; Belcher, Warwick; Dastoor, Paul

    2011-12-01

    Despite the fact that the performance of organic solar cells is generally susceptible to degradation by moisture exposure, there has been suggestion that the photoactive layer (P3HT) is surprisingly resilient. This work attempts to confirm the stability of P3HT as an organic solar cell material by deliberately introducing water into the photoactive layer. A dramatic step drop in device performance during cell characterization is observed approximately one day after the device has been fabricated. The time-delayed step drop in output efficiency strongly suggests that moisture has little effect on the P3HT conducting polymer.

  14. High-voltage engineering

    Microsoft Academic Search

    Khalifa

    1990-01-01

    The topics covered in this book include gas discharge, insulating materials, system earthing, overvoltage and insulation coordination, and high-voltage equipment and testing techniques. In two chapters, the principles of design of high-voltage busbars are discussed, together with their insulation and ampacity, whether they are of conventional air-insulated type or the metal-clad GIS types now widely used at the HV and

  15. Low-voltage gyrotrons

    SciTech Connect

    Glyavin, M. Yu.; Zavolskiy, N. A.; Sedov, A. S. [Institute of Applied Physics RAS, N. Novgorod 603600 (Russian Federation); Nusinovich, G. S. [IREAP, University of Maryland, College Park, Maryland 20742-3511 (United States)

    2013-03-15

    For a long time, the gyrotrons were primarily developed for electron cyclotron heating and current drive of plasmas in controlled fusion reactors where a multi-megawatt, quasi-continuous millimeter-wave power is required. In addition to this important application, there are other applications (and their number increases with time) which do not require a very high power level, but such issues as the ability to operate at low voltages and have compact devices are very important. For example, gyrotrons are of interest for a dynamic nuclear polarization, which improves the sensitivity of the nuclear magnetic resonance spectroscopy. In this paper, some issues important for operation of gyrotrons driven by low-voltage electron beams are analyzed. An emphasis is made on the efficiency of low-voltage gyrotron operation at the fundamental and higher cyclotron harmonics. These efficiencies calculated with the account for ohmic losses were, first, determined in the framework of the generalized gyrotron theory based on the cold-cavity approximation. Then, more accurate, self-consistent calculations for the fundamental and second harmonic low-voltage sub-THz gyrotron designs were carried out. Results of these calculations are presented and discussed. It is shown that operation of the fundamental and second harmonic gyrotrons with noticeable efficiencies is possible even at voltages as low as 5-10 kV. Even the third harmonic gyrotrons can operate at voltages about 15 kV, albeit with rather low efficiency (1%-2% in the submillimeter wavelength region).

  16. Cryopreservation of Quercus suber somatic embryos by encapsulation-dehydration and evaluation of genetic stability.

    PubMed

    Fernandes, Pedro; Rodriguez, Eleazar; Pinto, Glória; Roldán-Ruiz, Isabel; De Loose, Marc; Santos, Conceição

    2008-12-01

    We describe an encapsulation and dehydration procedure for the cryopreservation of cork oak (Quercus suber L.) somatic embryos that resulted in at least 90% survival. Genetic stability of the regenerated material was assessed by flow cytometry (FCM), amplified fragment length polymorphisms (AFLP) and simple sequence repeats (SSR). Cryopreservation of embryogenic clusters involved encapsulation of each cluster in an alginate bead, followed by a 3-day culture in 0.7 M sucrose and subsequent desiccation to 25 or 35% water content (WC), followed by freezing in liquid nitrogen. Thawed, cryopreserved somatic embryos had high viability and exhibited long-term survival. No morphological differences were observed between somatic embryos desiccated to 25 and 35% WC. Analysis of DNA ploidy stability of control (i.e., encapsulated and dehydrated but not frozen) and cryopreserved material by flow cytometry showed no significant differences. Similarly, DNA-marker analyses (AFLPs and SSR) revealed no significant differences between control and cryopreserved samples at the DNA-sequence level. Nonetheless, because polymorphisms were found between control material and samples cryopreserved and desiccated to 25% WC, the 35% WC method is recommended for cryopreservation of this tissue type. Cryopreservation of Q. suber somatic embryos by this encapsulation-dehydration procedure has potential for use in long-term conservation programs. PMID:19193567

  17. Critical evaluation of the unsteady aerodynamics approach to dynamic stability at high angles of attack

    NASA Technical Reports Server (NTRS)

    Hui, W. H.

    1985-01-01

    Bifurcation theory is used to analyze the nonlinear dynamic stability characteristics of an aircraft subject to single-degree-of-freedom. The requisite moment of the aerodynamic forces in the equations of motion is shown to be representable in a form equivalent to the response to finite amplitude oscillations. It is shown how this information can be deduced from the case of infinitesimal-amplitude oscillations. The bifurcation theory analysis reveals that when the bifurcation parameter is increased beyond a critical value at which the aerodynamic damping vanishes, new solutions representing finite amplitude periodic motions bifurcate from the previously stable steady motion. The sign of a simple criterion, cast in terms of aerodynamic properties, determines whether the bifurcating solutions are stable or unstable. For the pitching motion of flat-plate airfoils flying at supersonic/hypersonic speed and for oscillation of flaps at transonic speed, the bifurcation is subcritical, implying either the exchanges of stability between steady and periodic motion are accompanied by hysteresis phenomena, or that potentially large aperiodic departures from steady motion may develop.

  18. Analysis and test evaluation of the dynamic response and stability of three advanced turboprop models

    NASA Technical Reports Server (NTRS)

    Bansal, P. N.; Arseneaux, P. J.; Smith, A. F.; Turnberg, J. E.; Brooks, B. M.

    1985-01-01

    Results of dynamic response and stability wind tunnel tests of three 62.2 cm (24.5 in) diameter models of the Prop-Fan, advanced turboprop, are presented. Measurements of dynamic response were made with the rotors mounted on an isolated nacelle, with varying tilt for nonuniform inflow. One model was also tested using a semi-span wing and fuselage configuration for response to realistic aircraft inflow. Stability tests were performed using tunnel turbulence or a nitrogen jet for excitation. Measurements are compared with predictions made using beam analysis methods for the model with straight blades, and finite element analysis methods for the models with swept blades. Correlations between measured and predicted rotating blade natural frequencies for all the models are very good. The IP dynamic response of the straight blade model is reasonably well predicted. The IP response of the swept blades is underpredicted and the wing induced response of the straight blade is overpredicted. Two models did not flutter, as predicted. One swept blade model encountered an instability at a higher RPM than predicted, showing predictions to be conservative.

  19. Understanding Skill in EVA Mass Handling. Volume 4; An Integrated Methodology for Evaluating Space Suit Mobility and Stability

    NASA Technical Reports Server (NTRS)

    McDonald, P. Vernon; Newman, Dava

    1999-01-01

    The empirical investigation of extravehicular activity (EVA) mass handling conducted on NASA's Precision Air-Bearing Floor led to a Phase I SBIR from JSC. The purpose of the SBIR was to design an innovative system for evaluating space suit mobility and stability in conditions that simulate EVA on the surface of the Moon or Mars. The approach we used to satisfy the Phase I objectives was based on a structured methodology for the development of human-systems technology. Accordingly the project was broken down into a number of tasks and subtasks. In sequence, the major tasks were: 1) Identify missions and tasks that will involve EVA and resulting mobility requirements in the near and long term; 2) Assess possible methods for evaluating mobility of space suits during field-based EVA tests; 3) Identify requirements for behavioral evaluation by interacting with NASA stakeholders;.4) Identify necessary and sufficient technology for implementation of a mobility evaluation system; and 5) Prioritize and select technology solutions. The work conducted in these tasks is described in this final volume of the series on EVA mass handling. While prior volumes in the series focus on novel data-analytic techniques, this volume addresses technology that is necessary for minimally intrusive data collection and near-real-time data analysis and display.

  20. Linking measurements of biodegradability, thermal stability and chemical composition to evaluate the effects of management on soil organic matter

    NASA Astrophysics Data System (ADS)

    Gregorich, Ed; Gillespie, Adam; Beare, Mike; Curtin, Denis; Sanei, Hamed; Yanni, Sandra

    2015-04-01

    The stability of soil organic matter (SOM) as it relates to resistance to microbial degradation has important implications for nutrient cycling, emission of greenhouse gases, and C sequestration. Hence, there is interest in developing new ways to accurately quantify and characterise the labile and stable forms of soil organic C. Our objectives in this study were to evaluate and describe relationships among the biodegradability, thermal stability and chemistry of SOM in soil under widely contrasting management regimes. Samples from the same soil under permanent pasture, an arable cropping rotation, and chemical fallow were fractionated (sand: 2000-50 ?m; silt: 50-5 ?m, and clay: < 5 ?m). Biodegradability of the SOM in size fractions and whole soils was assessed in a laboratory mineralization study. The chemical composition of SOM was characterized by X-ray absorption near-edge structure (XANES) spectroscopy at the K-edge and its thermal stability was determined by analytical pyrolysis using a Rock-Eval pyrolyser. The mineralization bioassay showed that whole soils and soil fractions under fallow were less susceptible to biodegradation than other managements and that sand-associated organic matter was significantly more susceptible than that in the silt or clay fractions. Analysis by XANES showed accumulation of carboxylates and strong depletion of amides (protein) and aromatics in the fallow whole soil. Moreover, protein depletion was most significant in the sand fraction of the fallow soil. Sand fractions in fallow and cropped soils were, however, enriched in plant-derived phenols, aromatics and carboxylates compared to the sand fraction of pasture soils. In contrast, ketones, which have been identified as products of microbially-processed organic matter, were slightly enriched in the silt fraction of the pasture soil. These data suggest reduced inputs and cropping restrict the decomposition of plant residues and, without supplemental N additions, protein-N in native SOM is significantly mineralized in fallow systems to meet microbial C mineralization demands. Analytical pyrolysis showed distinct differences in the thermal stability of SOM among the size fractions and management treatments; it also showed that the loss of SOM generally involved dehydrogenation. The temperature at which half of the C was pyrolyzed showed strong correlation with mineralizable C and thus provides solid evidence for a link between the biological and thermal stability of SOM.

  1. Voltage collapse proximity index determination using voltage phasors approach

    Microsoft Academic Search

    F. Gubina; B. Strmcnik

    1995-01-01

    In the paper, a “phasor concept” of voltage collapse proximity determination is presented. An adequate voltage proximity index is calculated based on the voltage phasor values only. Furthermore, an algorithm is derived which automatically detects the network transmission paths to the load nodes which are prone to voltage collapse due to additional real or reactive loading. The algorithm is tested

  2. Evaluation of the stability, bioavailability, and hypersensitivity of the omega-3 derived anti-leukemic prostaglandin: ?(12)-prostaglandin J3.

    PubMed

    Kudva, Avinash K; Kaushal, Naveen; Mohinta, Sonia; Kennett, Mary J; August, Avery; Paulson, Robert F; Prabhu, K Sandeep

    2013-01-01

    Previous studies have demonstrated the ability of an eicosapentaenoic acid (EPA)-derived endogenous cyclopentenone prostaglandin (CyPG) metabolite, ?(12)-PGJ3, to selectively target leukemic stem cells, but not the normal hematopoietic stems cells, in in vitro and in vivo models of chronic myelogenous leukemia (CML). Here we evaluated the stability, bioavailability, and hypersensitivity of ?(12)-PGJ3. The stability of ?(12)-PGJ3 was evaluated under simulated conditions using artificial gastric and intestinal juice. The bioavailability of ?(12)-PGJ3 in systemic circulation was demonstrated upon intraperitoneal injection into mice by LC-MS/MS. ?(12)-PGJ3 being a downstream metabolite of PGD3 was tested in vitro using primary mouse bone marrow-derived mast cells (BMMCs) and in vivo mouse models for airway hypersensitivity. ZK118182, a synthetic PG analog with potent PGD2 receptor (DP)-agonist activity and a drug candidate in current clinical trials, was used for toxicological comparison. ?(12)-PGJ3 was relatively more stable in simulated gastric juice than in simulated intestinal juice that followed first-order kinetics of degradation. Intraperitoneal injection into mice revealed that ?(12)-PGJ3 was bioavailable and well absorbed into systemic circulation with a Cmax of 263 µg/L at 12 h. Treatment of BMMCs with ZK118182 for 12 h resulted in increased production of histamine, while ?(12)-PGJ3 did not induce degranulation in BMMCs nor increase histamine. In addition, in vivo testing for hypersensitivity in mice showed that ZK118182 induces higher airways hyperresponsiveness when compared ?(12)-PGJ3 and/or PBS control. Based on the stability studies, our data indicates that intraperitoneal route of administration of ?(12)-PGJ3 was favorable than oral administration to achieve effective pharmacological levels in the plasma against leukemia. ?(12)-PGJ3 failed to increase histamine and IL-4 in BMMCs, which is in agreement with reduced airway hyperresponsiveness in mice. In summary, our studies suggest ?(12)-PGJ3 to be a promising bioactive metabolite for further evaluation as a potential drug candidate for treating CML. PMID:24312486

  3. High voltage variable diameter insulator

    DOEpatents

    Vanacek, D.L.; Pike, C.D.

    1982-07-13

    A high voltage feedthrough assembly having a tubular insulator extending between the ground plane ring and the high voltage ring. The insulator is made of Pyrex and decreases in diameter from the ground plane ring to the high voltage ring, producing equipotential lines almost perpendicular to the wall of the insulator to optimize the voltage-holding capability of the feedthrough assembly.

  4. Stability of Repeated Student Evaluations of Teaching in the Second Preclinical Year of a Medical Curriculum

    ERIC Educational Resources Information Center

    Krantz-Girod, Catherine; Bonvin, Raphael; Lanares, Jacques; Cueanot, Seagoleine; Feihl, Francois; Bosman, Fred; Waeber, Bernard

    2004-01-01

    The second preclinical year of the medical curriculum at the Medical Faculty of the University of Lausanne in Switzerland includes nine multidisciplinary organ-system-oriented modules consisting of lectures and problem-based-learning tutorials. This study reports the experience accumulated with the evaluation of lectures during the academic years…

  5. An evaluation of biomass yield stability of switchgrass ( Panicum virgatum L.) cultivars

    Microsoft Academic Search

    N Sharma; I Piscioneri; V Pignatelli

    2003-01-01

    The present work deals with evaluation of the adaptation and biomass production of various switchgrass cultivars (upland and lowland type) in Southern Italy. A field trial was established in 1998 with 15 switchgrass varieties in ENEA Trisaia (Matera). The experiment was conducted for four years (1998–2001). During each growing period, a series of measurements were taken. At the end of

  6. Evaluation of the Low-Speed Stability and Control Characteristics of a Mach 5.5 Waverider Concept

    NASA Technical Reports Server (NTRS)

    Hahne, David E.

    1997-01-01

    Static force and moment tests of a 0.062-scale model of a hypersonic vehicle study concept known as the LOFLYTE(TM) configuration were conducted in the Langley 12-Foot Low-Speed Tunnel. These tests looked primarily at the low-speed static stability and control characteristics of this configuration. Data were obtained over an angle-of-attack range of -5 deg. to 22 deg. at sideslip angles that ranged between -10 deg. and 10 deg. The tiperons were sized to provide enough pitch control to trim the vehicle up to alpha = 16 deg. with no more than 10 deg. of surface deflection and data obtained in this test showed that 10 deg. of tiperon deflection was nearly sufficient to trim the configuration up to the desired angle of attack. Because of the pitching-moment characteristics of the LOFLYTE(TM) configuration, there is a reasonably high level of unpowered trimmed lift at nominal takeoff and approach to landing that should allow for acceptable takeoff and landing speeds for this vehicle. Initial evaluation of the directional stability characteristics of this configuration showed a significant instability between alpha = 10 deg. and about alpha = 18 deg. This test determined that the cause of this instability was the interaction of the wing leading-edge vortex with the vertical tails. Moving the vertical tails either inboard or outboard from the baseline location eliminated this unfavorable interaction.

  7. Evaluation of Disulfide Bond Position to Enhance the Thermal Stability of a Highly Stable Single Domain Antibody

    PubMed Central

    Zabetakis, Dan; Olson, Mark A.; Anderson, George P.; Legler, Patricia M.; Goldman, Ellen R.

    2014-01-01

    Single domain antibodies are the small recombinant variable domains derived from camelid heavy-chain-only antibodies. They are renowned for their stability, in large part due to their ability to refold following thermal or chemical denaturation. In addition to refolding after heat denaturation, A3, a high affinity anti-Staphylococcal Enterotoxin B single domain antibody, possesses a melting temperature of ?84°C, among the highest reported for a single domain antibody. In this work we utilized the recently described crystal structure of A3 to select locations for the insertion of a second disulfide bond and evaluated the impact that the addition of this second bond had on the melting temperature. Four double-disulfide versions of A3 were constructed and each was found to improve the melting temperature relative to the native structure without reducing affinity. Placement of the disulfide bond at a previously published position between framework regions 2 and 3 yielded the largest improvement (>6°C), suggesting this location is optimal, and seemingly provides a universal route to raise the melting temperature of single domain antibodies. This study further demonstrates that even single domain antibodies with extremely high melting points can be further stabilized by addition of disulfide bonds. PMID:25526640

  8. Development and evaluation of interface-stabilized and reactive-sputtered oxide-capped multilayers for EUV lithography

    NASA Astrophysics Data System (ADS)

    Kriese, Michael; Platonov, Yuriy; Rodriguez, Jim; Fournier, Gary; Grantham, Steven; Tarrio, Charles; Curry, John; Hill, Shannon; Lucatorto, Thomas

    2015-03-01

    A critical component of high-performance EUV lithography source optics is the reflecting multilayer coating. The ideal multilayer will have both high reflectance and high stability to thermal load. Additionally the capping layers must provide resistance to degradations from exposure to an EUV source, and also be compatible with, or enhance, the systems used for cleaning an exposed multilayer coating. We will report on the results of development of C and B4C stabilized Mo/Si multilayers used to increase the as-deposited peak reflectivity (Rp) as well as decreasing the loss of peak reflectivity (Rp) as a function of annealing temperature. Previous results demonstrate that these layers prevent loss of Rp for temperatures up to 600º C. Results on the use of reactively-sputtered oxide capping layers such as SiO2 and ZrO2 will be presented as well, along with results of exposure testing. The deposition is performed in a dual processchamber inline magnetron system, using reactive sputtering for the production of capping layers. The reflectometer and exposure apparatus at the NIST Physics Laboratory is used for evaluation of the performance. Exposure results on the resistance to oxidation in the presence of water vapor will be presented and discussed.

  9. Novel SiL evaluation of an optimal H? controller on the stability of a MAV in flight simulator

    NASA Astrophysics Data System (ADS)

    Sampaio, Rafael C. B.; Becker, Marcelo; Siqueira, Adriano A. G.; Freschi, Leonardo W.; Montanher, Marcelo P.

    This paper introduces a novel methodology to assist the evaluation of control algorithms for MAVs (Micro Aerial Vehicles) using Software-in-the-Loop (SiL) based flight simulation. The originality of this paper is to use © Microsoft Flight Simulator (MSFS) as the environment to embed both the dynamic and graphic models of © Ascending Technologies Pelican MAV flying robot. The resulting is a reliable model of the Pelican quadrotor. The full duplex communication between the virtual aircraft and the control algorithm is achieved by a custom C++/C software named FVMS (Flight Variables Management System), developed by Aerial Robots Team (ART), which is able to reach (read/write) a great number of flight variables from MSFS. To illustrate the effectiveness of such method, we first completely present FVMS architecture and main features. Later, the synthesis and then the application of the optimal H? robust control algorithm and its operation into the FVMS SiL context are explained. Regarding MAVs control evaluation, SiL simulation considerably contributes to save battery time, to ease control synthesis and prototyping and to prevent accidents during tests with the real robot. The final goal is to evaluate the stability of the Pelican platform in hovering tasks in flight simulation focusing on the efficiency of FVMS to properly run the optimal H? robust control algorithm. The SiL control of the MAV has proven FVMS capabilities, which may be extended to assist the design of other classes of controllers.

  10. Community mental health centres initiated by the South-Eastern Europe Stability Pact: evaluation in seven countries.

    PubMed

    Priebe, Stefan; Matanov, Aleksandra; Demi, Neli; Blagovcanin Simic, Joka; Jovanovic, Sandra; Gajic, Milena; Radonic, Elizabeta; Bajraktarov, Stojan; Boderscova, Larisa; Konatar, Monika; Nica, Raluca; Muijen, Matthijs

    2012-06-01

    Eight community mental health care centres (initiated by the South-Eastern Europe Stability Pact) in Albania, Bosnia-Herzegovina, Croatia, Macedonia, Moldova, Montenegro and Romania were evaluated. Characteristics of patients, patient reported outcomes and patient views of care were assessed in 305 psychiatric patients. Patient characteristics varied across centres, with most patients having long term psychotic disorders. Treatment satisfaction and therapeutic relationships were rated favourably. Subjective quality of life mean scores were rather low, with higher satisfaction with health and dissatisfaction with the financial and employment situation. Being unemployed was the only factor associated with poor quality of life and lower treatment satisfaction. Most developing centres target patients with persistent psychotic disorders. Care appears highly valued by the patients. The findings encourage establishing more centres in the region and call for employment schemes for people with mental illnesses. PMID:21617994

  11. Evaluation of a Treadmill with Vibration Isolation and Stabilization (TVIS) for Use on the International Space Station

    NASA Technical Reports Server (NTRS)

    McCrory, Jean L.; Lemmon, David R.; Sommer, H. Joseph; Prout, Brian; Smith, Damon; Korth, Deborah W.; Lucero, Javier; Greenisen, Michael; Moore, Jim

    1999-01-01

    A treadmill with vibration isolation and stabilization designed for the International Space Station (ISS) was evaluated during Shuttle mission STS-81. Three crew members ran and walked on the device, which floats freely in zero gravity. For the majority of the more than 2 hours of locomotion studied, the treadmill showed peak to peak linear and angular displacements of less than 2.5 cm and 2.5 deg, respectively. Vibration transmitted to the vehicle was within the microgravity allocation limits that are defined for the ISS. Refinements to the treadmill and harness system are discussed. This approach to treadmill design offers the possibility of generating 1G-like loads on the lower extremities while preserving the microgravity environment of the ISS for structural safety and vibration free experimental conditions.

  12. Evaluation of the Effect of Ultraviolet Disinfection on Dimensional Stability of the Polyvinyl Silioxane Impressions.” an in-Vitro Study

    PubMed Central

    Godbole, Surekha R; Dahane, Trupti M; Nimonkar, Sharayu V

    2014-01-01

    Introduction: Infection control is an important concept in the present day practice of dentistry. The prosthodontists are at an added risk of transmission because of the infection spreading through the contaminated lab equipments while working in the lab. The purpose of this study is to evaluate the effect of UV light disinfection on dimensional stability of polyvinyl siloxane impressions. Materials and Methods : Impressions were made in perforated custom tray. After polymerization of impression, half the samples were disinfected in UV light and remaining samples were not subjected to disinfection and poured in die stone which served as control group. Linear dimensions were measured on the cast with travelling microscope of 0.001accuracy. Result : The result showed that UV light disinfectant showed no significant dimensional changes on impressions. Conclusion: Hence, it can be safely used to disinfect impressions in clinical prosthodontic procedures. PMID:25386528

  13. CSER 00-003 Criticality Safety Evaluation report for PFP Magnesium Hydroxide Precipitation Process for Plutonium Stabilization Glovebox 3

    SciTech Connect

    LAN, J.S.

    2000-07-13

    This Criticality Safety Evaluation Report analyzes the stabilization of plutonium/uranium solutions in Glovebox 3 using the magnesium hydroxide precipitation process at PFP. The process covered are the receipt of diluted plutonium solutions into three precipitation tanks, the precipitation of plutonium from the solution, the filtering of the plutonium precipitate from the solution, the scraping of the precipitate from the filter into boats, and the initial drying of the precipitated slurry on a hot plate. A batch (up to 2.5 kg) is brought into the glovebox as plutonium nitrate, processed, and is then removed in boats for further processing. This CSER establishes limits for the magnesium hydroxide precipitation process in Glovebox 3 to maintain criticality safety while handling fissionable material.

  14. Evaluation of the BD Vacutainer® RST blood collection tube for routine chemistry analytes: clinical significance of differences and stability study

    PubMed Central

    Kocijancic, Marija; Cargonja, Jelena; Delic-Knezevic, Alma

    2014-01-01

    Introduction: Preanalytical variables account for most of laboratory errors. There is a wide range of factors that affect the reliability of laboratory report. Most convenient sample type for routine laboratory analysis is serum. BD Vacutainer® Rapid Serum Tube (RST) (Becton, Dickinson and Company, Franklin Lakes, NJ, USA) blood collection tube provides rapid clotting time allowing fast serum separation. Our aim was to evaluate the comparability of routine chemistry parameters in BD Vacutainer® RST blood collection tube in reference with the BD Vacutainer® Serum Separating Tubes II Advance Tube (SST) (Becton, Dickinson and Company, Franklin Lakes, NJ, USA). Materials and methods: Blood specimens were collected from 90 participants for evaluation on its results, clotting time and stability study of six routine biochemistry parameters: glucose (Glu), aspartate aminotransferase (AST), alanine aminotransferase (ALT), calcium (Ca), lactate dehidrogenase (LD) and potassium (K) measured with Olympus AU2700 analyzer (Beckman Coulter, Tokyo, Japan). The significance of the differences between samples was assessed by paired t-test or Wilcoxon Matched-Pairs Rank test after checking for normality. Results: Clotting process was significantly shorter in the RSTs compared to SSTs (2.49 min vs. 19.47 min, respectively; P < 0.001). There was a statistically significant difference between the RST and SST II tubes for glucose, calcium and LD (P < 0.001). Differences for glucose and LD were also clinically significant. Analyte stability studies showed that all analytes were stable for 24 h at 4 °C. Conclusions: Most results (except LD and glucose) from RST are comparable with those from SST. In addition, RST tube provides shorter clotting time. PMID:25351355

  15. An evaluation of prediction accuracy and stability of a new vegetation index for estimating vegetation leaf area index

    NASA Astrophysics Data System (ADS)

    Jiang, Hailing; Zhang, Lifu; Yang, Hang; Chen, Xiaoping; Wang, Shudong; Li, Xueke; Liu, Kai

    2014-11-01

    LAI is a crucial parameter and a basic quantity indicating crop growth situation. Empirical models comprising spectral indices (SIs) and LAI have widely been applied to the retrieval of LAI. SI method already has exhibited feasibility in the estimation of vegetation LAI. However, it is largely subject to the inconsistency from different remote sensors which have varied specifications, such as spectral response features and central wavelength. To address this issue, a new vegetation index (VIUPD) based on the universal pattern decomposition method was proposed. It is expressed as a linear sum of the pattern decomposition coefficients and features in sensor-independency. The aim of this study was to evaluate the prediction accuracy and stability of VIUPD for estimating LAI, compared with three other common-used SIs. In this study, the measured spectra were resampled to simulated TM multispectral data and Hyperion hyperspectral data respectively, using the Gaussian spectral response function. The three typical SIs chosen were including NDVI, TVI and MCARI, which were constructed with the sensitive bands to the LAI. Finally, the regression equations between four selected SIs and LAI were established. The best index evaluated using the simulated TM data was VIUPD which exhibits the best correlation with LAI (R2=0.92) followed by NDVI (R2=0.80). For the simulated Hyperion data, VIUPD again ranks first with R2=0.89, followed by TVI (R2=0.63). Meanwhile, the consistence of VIUPD also was studied based on simulated TM and Hyperion sensor data and the R2 reached to 0.95. It is demonstrated that VIUPD has the best accuracy and stability to estimate LAI of winter wheat whether using simulated TM data or Hyperion data, which reaffirms that VIUPD is comparatively sensor independent.

  16. Electron launching voltage monitor

    DOEpatents

    Mendel, Clifford W. (Albuquerque, NM); Savage, Mark E. (Albuquerque, NM)

    1992-01-01

    An electron launching voltage monitor measures MITL voltage using a relationship between anode electric field and electron current launched from a cathode-mounted perturbation. An electron launching probe extends through and is spaced from the edge of an opening in a first MITL conductor, one end of the launching probe being in the gap between the MITL conductor, the other end being adjacent a first side of the first conductor away from the second conductor. A housing surrounds the launching probe and electrically connects the first side of the first conductor to the other end of the launching probe. A detector detects the current passing through the housing to the launching probe, the detected current being representative of the voltage between the conductors.

  17. Evaluation of a ventricular assist device: stability under x-rays and therapeutic beam attenuation.

    PubMed

    Gossman, Michael S; Graham, Joel D; Tamez, Dan; Voskoboynikov, Neil; Larose, Jeffrey A

    2012-01-01

    Improved outcomes and quality of life of heart failure patients have been reported with the use of left ventricular assist devices (LVADs). However, little information exists regarding devices in patients undergoing radiation cancer treatment. Two HeartWare Ventricular Assist Device (HVAD) pumps were repeatedly irradiated with high intensity 18 MV x-rays to a dosage range of 64-75 Gy at a rate of 6 Gy/min from a radiation oncology particle accelerator to determine operational stability. Pump parameter data was collected through a data acquisition system. Second, a computerized tomography (CT) scan was taken of the device, and a treatment planning computer estimated characteristics of dose scattering and attenuation. Results were then compared with actual radiation measurements. The devices exhibited no changes in pump operation during the procedure, though the titanium components of the HVAD markedly attenuate the therapy beam. Computer modeling indicated an 11.8% dose change in the absorbed dosage that was distinctly less than the 84% dose change measured with detectors. Simulated and measured scattering processes were negligible. Computer modeling underestimates pretreatment dose to patients when the device is in the field of radiation. Future x-ray radiation dosimetry and treatment planning in HVAD patients should be carefully managed by radiation oncology specialists. PMID:22236626

  18. Oxidative stability and shelf-life evaluation of selected culinary oils.

    PubMed

    Kochhar, S Parkash; Henry, C Jeya K

    2009-01-01

    Four out of eight 'healthier' oils-namely, almond oil, avocado oil, hazelnut oil and macadamia nut oil-studied were rich sources of monounsaturated fatty acids like olive oil. Grape seed oil, rice barn oil (marketed recently), toasted sesame oil and walnut oil contained high levels of essential fatty acids. The order of oxidative stability determined by Rancimat measuring of the induction period at four temperatures (90 degrees C, 100 degrees C, 110 degrees C, and 120 degrees C) was found to be macadamia oil > rice bran oil approximately toasted sesame oil > avocado oil > almond oil > hazelnut oil > grape seed oil > walnut oil. High-level monounsaturated fatty acid oils gave a linear relationship between 100 times the reciprocal of the induction period against the total unsaturated fatty acid content obtained as %C18:2 + 0.08 x C18:1 + 2.08 x %C18:3, while the polyunsaturated fatty acid oils gave an exponential relationship. In the case of rice bran and hazelnut oils, shelf-life prediction from the extrapolation of the Arrhenius plots and the Q(10) factors was compared well with that of storage time given by the oil producers. In the cases of the other oils (with an exception of macadamia nut oil), the predicted shelf-lives were significantly lower than that of the storage times; especially, walnut oil (very prone to oxidation) gave 15-20 times lower shelf-life than the best-before storage life. PMID:19634067

  19. Evaluation of the stability indices for the thunderstorm forecasting in the region of Belgrade, Serbia

    NASA Astrophysics Data System (ADS)

    Vujovi?, D.; Paskota, M.; Todorovi?, N.; Vu?kovi?, V.

    2015-07-01

    The pre-convective atmosphere over Serbia during the ten-year period (2001-2010) was investigated using the radiosonde data from one meteorological station and the thunderstorm observations from thirteen SYNOP meteorological stations. In order to verify their ability to forecast a thunderstorm, several stability indices were examined. Rank sum scores (RSSs) were used to segregate indices and parameters which can differentiate between a thunderstorm and no-thunderstorm event. The following indices had the best RSS values: Lifted index (LI), K index (KI), Showalter index (SI), Boyden index (BI), Total totals (TT), dew-point temperature and mixing ratio. The threshold value test was used in order to determine the appropriate threshold values for these variables. The threshold with the best skill scores was chosen as the optimal. The thresholds were validated in two ways: through the control data set, and comparing the calculated indices thresholds with the values of indices for a randomly chosen day with an observed thunderstorm. The index with the highest skill for thunderstorm forecasting was LI, and then SI, KI and TT. The BI had the poorest skill scores.

  20. First-year evaluation of low-level waste-management stabilization techniques

    SciTech Connect

    Cox, G.R.

    1981-12-01

    The first year of observation for effectiveness of biobarriers and herbicides in revegetation efforts demonstrated that certain practices will result in successful site stabilization: proper orientation of burial trench to reduce erosion; utilization of mulches to conserve moisture; seeding mixed perennial or annual grass species at the proper time for optimization of establishment and growth; and applying 2,4-D amine/Dicamba selective herbicide at the optimum time for enhancement of disirable grasses and reduction of competition from other species. The ultimate success or failure of a revegetation operation depends in part on the availability of equipment and manpower, weather conditions, and engineering feasibility. The data indicated that perennial grasses offered advantages over annual grasses and that the 2,4-D amine/Dicamba herbicide spray program was successful and should be expanded for next year. However, programmatic decisions should not be based on the data for 1 year, but should be based on data gathered over the full 3 years of the project.

  1. Epoxidized Soybean Oil: Evaluation of Oxidative Stabilization and Metal Quenching/Heat Transfer Performance

    NASA Astrophysics Data System (ADS)

    Simencio Otero, Rosa L.; Canale, Lauralice C. F.; Said Schicchi, Diego; Agaliotis, Eliana; Totten, George E.; Sánchez Sarmiento, Gustavo

    2013-07-01

    Vegetable and animal oils as a class of fluids have been used for hundreds of years, if not longer, as quenchants for hardening steel. However, when petroleum oils became available in the late 1800s and early 1900s, the use of these fluids as quenchants, in addition to their use in other industrial oil applications, quickly diminished. This was primarily, but not exclusively, due to their generally very poor thermal-oxidative instability and the difficulty for formulating fluid analogs with varying viscosity properties. Interest in the use of renewable fluids, such as vegetable oils, has increased dramatically in recent years as alternatives to the use of relatively non-biodegradable and toxic petroleum oils. However, the relatively poor thermal-oxidative stability has continued to be a significant reason for their general non-acceptance in the marketplace. Soybean oil (SO) is one of the most highly produced vegetable oils in Brazil. Currently, there are commercially produced epoxidized versions of SO which are available. The objective of this paper is to discuss the potential use of epoxidized SO and its heat transfer properties as a viable alternative to petroleum oils for hardening steel.

  2. Self micro-emulsifying drug delivery system of tacrolimus: Formulation, in vitro evaluation and stability studies

    PubMed Central

    Patel, Pranav V; Patel, Hitesh K; Panchal, Shital S; Mehta, Tejal A

    2013-01-01

    Background: Tacrolimus has poor solubility in water ranging from 4 to 12 ?g/mL. The oral bio availabilities of tacrolimus is poor and exhibits high intra and inter-subject variability (4-89%, average 25%) in the liver and the kidney transplant recipients and in patients with renal impairment. Aim: The present study deals with the development and characterization of self-micro-emulsifying drug delivery system to improve the oral bioavailability of poorly soluble drug tacrolimus. Materials and Methods: Solubility of the tacrolimus was estimated in various oils, surfactants, and co-surfactants. Various in vitro tests such as percentage transmittance, emulsification time, cloud point, precipitation, and thermodynamic stabilities were used to find out optimized formulations. Optimized liquid self micro-emulsifying (SMEDDS) were characterized by particle size analysis and converted in solid by using the Florite RE as an adsorbent, which is further characterized by differential scanning calorimetry (DSC), scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), and particle size analysis. Results: The optimized liquid SMEDDS formulation contained 10% Lauroglycol FCC as an oil, 60% Cremophor RH, and 30% PEG (polyethylene glycol) 400 as a surfactant and co-surfactant respectively. The optimized liquid and solid SMEDDS showed higher drug release than the marketed capsule and pure API (active pharmaceutical ingredient) powder. For optimized liquid SMEDDS and solid SMEDDS, the globule sizes were found 113 nm and 209 nm respectively. The solid state characterization of solid-SMEDDS by SEM, DSC, FTIR, and XRD revealed the absence of crystalline tacrolimus in the solid-SMEDDS. Shelf-lives for liquid SMEDDS and solid SMEDDS were found to be 1.84 and 2.25 year respectively. Conclusions: The results indicate that liquid SMEDDS and solid SMEDDS of tacrolimus, owing to nano-sized, have potential to enhance the absorption of the drug. PMID:24015381

  3. Lipid nanocarriers (GeluPearl) containing amphiphilic lipid Gelucire 50/13 as a novel stabilizer: fabrication, characterization and evaluation for oral drug delivery

    NASA Astrophysics Data System (ADS)

    Date, Abhijit A.; Vador, Nimish; Jagtap, Aarti; Nagarsenker, Mangal S.

    2011-07-01

    Purpose. To evaluate the ability of Gelucire 50/13 (an amphiphilic lipid excipient) to act as a stabilizer for lipid nanocarriers such as solid lipid nanoparticles (SLN) and nanostructured lipid carriers (NLC) and to establish the ability of Gelucire 50/13 based lipid nanocarriers to improve oral delivery of hydrophobic drugs using repaglinide (RPG) as a model drug. Methods. The ability of Gelucire 50/13 to nanosize various solid lipids was evaluated. The ability of Gelucire 50/13 to yield NLC was evaluated by using Precirol ATO 5 as a model solid lipid and various liquid lipids (oils). Gelucire 50/13 based NLC (GeluPearl) were evaluated for their ability to improve the efficacy of RPG on oral administration in comparison to RPG tablets. The short term stability of RPG-GeluPearl was evaluated at 25 °C/60% RH. Results. Gelucire 50/13 could successfully yield SLN and NLC of various solid lipids, demonstrating its potential to act as a novel stabilizer. DSC studies indicated that Gelucire 50/13 interacts with Precirol ATO 5 and this interaction suppresses polymorphic transitions of both the components. RPG-GeluPearl exhibited significantly higher anti-diabetic activity compared to marketed RPG tablets. RPG-GeluPearl demonstrated good colloidal and chemical stability at the end of 1 month. Indian patent application number 2167/MUM/2008.

  4. Voltage-Controlled Oscillator

    NASA Technical Reports Server (NTRS)

    1995-01-01

    Integrated Component Systems, Inc. incorporated information from a NASA Tech Briefs article into a voltage-controlled oscillator it designed for a customer. The company then applied the technology to its series of phase-locked loop synthesizers, which offer superior phase noise performance.

  5. Characterization CurrentVoltage

    E-print Network

    Luryi, Serge

    Injection Charge of Characterization Current­Voltage Continuation Predictor­Corrector Using or transistor injection charge The 1 which device heterojunction three­terminal a is over field, lateral to ability the Further, heating. carrier for terms multivalued arbitrary, tracing for essential is conditions

  6. Transient Voltage Decoupling Elements

    Microsoft Academic Search

    J. E. Gruber

    1968-01-01

    Premature and inexact timing of thyratron generators may occur during parallel operation of capacitor discharge circuits. Voltage transients which enter the trigger circuits can be eliminated by decoupling spark gaps. A simple, two electrode, spark gap with corona illumination is described. The low jitter of this gap allows its insertion in the output line of a 15 kV thyratron generator

  7. Development of Automatic Voltage Regulator for Low Voltage Distribution Systems

    NASA Astrophysics Data System (ADS)

    Matsuda, Katsuhiro; Horikoshi, Kazuhiro; Seto, Toshiyuki; Iyama, Osamu; Kobayashi, Hiromu

    This paper presents the development of a new type of voltage regulator that can adequately maintain the voltage supplied to customers, dealing with the problem of voltage control along with the widespread use of photovoltaic power generation systems. The developed equipment is a pole-mounted type voltage regulator consisting of a step-down transformer that converts voltage from high to low and a series transformer for voltage compensation. The demonstration test conducted at the CRIEPI Akagi Test Center confirmed that the voltage control function of the developed voltage regulator is satisfactory based on the proposed control algorism. Also, simulation analysis, on the assumption of the clustered installation of photovoltaic power generation systems, confirmed that the introduction of the developed voltage regulator enables the system voltage to be adequately maintained and full photovoltaic power generation is possible without suppressing the output. It is anticipated that the developed voltage regulator is very effective in adequately regulating the voltage for low voltage distribution systems and gives an effective way for even more widespread photovoltaic power generation.

  8. Three Year RSA Evaluation of Vitamin E Diffused Highly Cross-linked Polyethylene Liners and Cup Stability.

    PubMed

    Sillesen, Nanna H; Greene, Meridith E; Nebergall, Audrey K; Nielsen, Poul T; Laursen, Mogens B; Troelsen, Anders; Malchau, Henrik

    2015-07-01

    Vitamin E diffusion into highly cross-linked polyethylene (E-XLPE) is a method for enhancing oxidative stability of acetabular liners. The purpose of this study was to evaluate in vivo penetration of E-XLPE using radiostereometric analysis (RSA). Eighty-four hips were recruited into a prospective 10-year RSA. This is the first evaluation of the multicenter cohort after 3-years. All patients received E-XLPE liners (E1, Biomet) and porous-titanium coated cups (Regenerex, Biomet). There was no difference (P=0.450) in median femoral head penetration into the E-XLPE liners at 3-years comparing cobalt-chrome heads (-0.028mm; inter-quartile range (IQR) - 0.065 to 0.047) with ceramic heads (-0.043mm, IQR - 0.143to0.042). The 3-year follow-up indicates minimal E-XLPE liner penetration regardless of head material and minimal early cup movement. PMID:25754257

  9. Control-matched computational evaluation of tendo-femoral contact in patients with posterior-stabilized total knee arthroplasty.

    PubMed

    Hoops, Heather E; Johnson, Derek R; Kim, Raymond H; Dennis, Douglas A; Baldwin, Mark A; Fitzpatrick, Clare K; Laz, Peter J; Rullkoetter, Paul J

    2012-09-01

    Painful patellar crepitus is a potential complication in up to 14% of patients following posterior-stabilized (PS) total knee arthroplasty (TKA). A recent clinical study identified influential patient and surgical variables by comparing a group of crepitus patients with controls matched for age, sex, and body mass index. The purpose of our study was to evaluate effects of variables identified as significant in the clinical study, including patellar ligament length, femoral component flexion, patellar button size, and position of the joint line, on contact between the quadriceps tendon and the PS femoral component. A previously verified finite element model was utilized to estimate tendo-femoral contact during deep flexion activity. Using discrete perturbations, the computational model confirmed the clinical findings in that an increased patellar ligament length, flexed femoral component, lowered joint line, and larger patellar component all reduced potentially deleterious contact near the intercondylar notch. With the selected level of anatomic and component alignment perturbations, the most influential factor affecting tendo-femoral contact was patellar ligament length. Three crepitus patients with matched controls were subsequently modeled, and contact with the anterior border of the notch was present in each crepitus patient, but none of the controls. Alternative surgical alignments for these patients were evaluated to improve the potential long-term outcomes. By characterizing conditions that may lead to painful crepitus, the modeling approach supports clinicians by identifying pre-surgical indicators and important alignment parameters to control intraoperatively. PMID:22298203

  10. Evaluation of the stability of uranyl peroxo-carbonato complex ions in carbonate media at different temperatures.

    PubMed

    Kim, Kwang-Wook; Lee, Keun-Young; Chung, Dong-Yong; Lee, Eil-Hee; Moon, Jei-Kwon; Shin, Dong-Woo

    2012-09-30

    This work studied the stability of peroxide in uranyl peroxo carbonato complex ions in a carbonate solution with hydrogen peroxide using absorption and Raman spectroscopies, and evaluated the temperature dependence of the decomposition characteristics of uranyl peroxo carbonato complex ions in the solution. The uranyl peroxo carbonato complex ions self-decomposed more rapidly into uranyl tris-carbonato complex ions in higher temperature carbonate solutions. The concentration of peroxide in the solution without free hydrogen peroxide represents the concentration of uranyl peroxo carbonato complex ions in a mixture of uranyl peroxo carbonato complex and uranyl tris-carbonato complex ions. The self-decomposition of the uranyl peroxo carbonato complex ions was a first order reaction, and its activation energy was evaluated to be 7.144×10(3) J mol(-1). The precipitation of sodium uranium oxide hydroxide occurred when the amount of uranyl tris-carbonato complex ions generated from the decomposition of the uranyl peroxo carbonato complex ions exceeded the solubility of uranyl tris-carbonato ions in the solution at the solution temperature. PMID:22831997

  11. Structural mechanism of voltage-dependent gating in an isolated voltage-sensing domain.

    PubMed

    Li, Qufei; Wanderling, Sherry; Paduch, Marcin; Medovoy, David; Singharoy, Abhishek; McGreevy, Ryan; Villalba-Galea, Carlos A; Hulse, Raymond E; Roux, Benoît; Schulten, Klaus; Kossiakoff, Anthony; Perozo, Eduardo

    2014-03-01

    The transduction of transmembrane electric fields into protein motion has an essential role in the generation and propagation of cellular signals. Voltage-sensing domains (VSDs) carry out these functions through reorientations of positive charges in the S4 helix. Here, we determined crystal structures of the Ciona intestinalis VSD (Ci-VSD) in putatively active and resting conformations. S4 undergoes an ~5-Å displacement along its main axis, accompanied by an ~60° rotation. This movement is stabilized by an exchange in countercharge partners in helices S1 and S3 that generates an estimated net charge transfer of ~1 eo. Gating charges move relative to a ''hydrophobic gasket' that electrically divides intra- and extracellular compartments. EPR spectroscopy confirms the limited nature of S4 movement in a membrane environment. These results provide an explicit mechanism for voltage sensing and set the basis for electromechanical coupling in voltage-dependent enzymes and ion channels. PMID:24487958

  12. Threshold Voltage of Si Single-Electron Transistor

    Microsoft Academic Search

    Akira Fujiwara; Seiji Horiguchi; Masao Nagase; Yasuo Takahashi

    2003-01-01

    We experimentally evaluate threshold voltages of Si single-electron transistors (SET) in order to investigate the effect of offset charges. Threshold voltages show a clear relation to the gate capacitance of SETs, which is a device parameter reflecting the size of the Si island of SETs. This indicates that the fabricated Si SETs do not suffer much from random offset charges

  13. Evaluation of an equine-optimized enzyme-linked immunosorbent assay for serum insulin measurement and stability study of equine serum insulin

    Microsoft Academic Search

    Josefine Öberg; Johan Bröjer; Owe Wattle; Inger Lilliehöök

    This study aims to evaluate a commercially available equine-optimized insulin assay and to evaluate the stability of equine\\u000a insulin. In addition, serum insulin concentrations before and after feeding are also presented. Samples were taken before\\u000a and after feeding from 40 healthy horses and from 15 equine patients visiting the University Equine Hospital. Insulin was\\u000a analysed with the equine ELISA and

  14. Voltage collapse proximity index determination using voltage phasors approach

    SciTech Connect

    Gubina, F.; Strmcnik, B. [Univ. of Ljubljana (Slovenia)] [Univ. of Ljubljana (Slovenia)

    1995-05-01

    In the paper, a phasor concept of voltage collapse proximity determination is presented. An adequate voltage proximity index is calculated based on the voltage phasor values only. Furthermore, an algorithm is derived which automatically detects the network transmission paths to the load nodes which are prone to voltage collapse due to additional real or reactive loading. The algorithm is tested on practical networks and exhibits comparable accuracy to the existing methods and low computing time consumption.

  15. Mechanism and CHARM2 Evaluation of P-Channel Metal Oxide Semiconductor Threshold Voltage Drop during High Density Plasma Heat-up Process

    Microsoft Academic Search

    Dong-Hwan Kim; Jeongyun Lee; Min-Sung Kim; Ken Tokashiki; Kyoungsub Shin; Woosung Han; Hyun-Il Kang; Eung-Kwon Kim; Joon-Tae Song

    2009-01-01

    Plasma damage during the plasma deposition process is one of the most critical device characteristic issues facing complementary metal oxide semiconductor field effect transistor (CMOSFET) technology. In this paper, the CHARM2 monitoring system is used to evaluate UV damage and plasma charging damage during a high density plasma chemical vapor deposition (HDP-CVD) heat-up process. As a result, the amount of

  16. TECHNOLOGY EVALUATION REPORT, SITE PROGRAM DEMONSTRATION OF THE INTERNATIONAL WASTE TECHNOLOGIES IN SITU STABILIZATION/-SOLIDIFICATION TECHNOLOGY, HIALEAH, FL, VOLUME II

    EPA Science Inventory

    A demonstration of the International Waste Technologies (IWT) process, utilizing the Geo-Con, Inc., deep-soil-mixing equipment has been performed under the Superfund Innovative Technology Evaluation (SITE) Program. his was the first field demonstration of an in situ stabilization...

  17. Immunohistochemical evaluation of the effects of paraffin section storage on biomarker stability.

    PubMed

    Ramos-Vara, J A; Webster, J D; DuSold, D; Miller, M A

    2014-01-01

    Environmental stresses can alter immunoreactivity of biomarkers in stored tissue sections. The effect of temperature and lighting on 49 cellular or microbial antigens was evaluated in 4 serial paraffin sections, cut 12 months, 10 months, 8 months, 5 months, 3 months, 1 month, 3 days, and 1 day before immunohistochemistry. Slides were stored at room temperature (RT) in the dark, at 4°C in the dark, at RT under fluorescent light, or at RT with windowpane exposure to sunlight. Immunohistochemistry was performed simultaneously in an automated immunostainer. Immunoreactivity was compared with that in the corresponding 1-day-old section and scored as 4 (<10% reduction), 3 (10%-25% reduction), 2 (26%-60% reduction), 1(>60% reduction), or 0 (no reactivity). Any loss of immunoreactivity was proportional to the tissue section age and was least in sections stored in the dark. Immunoreactivity was only completely lost in light-exposed sections and as early as 1 month for CD45. Other markers with complete loss of immunoreactivity were bovine viral diarrhea virus, CD18 (only with fluorescent light), CD31, CD68, canine parvovirus, chromogranins, and thyroid transcription factor-1. Markers with complete loss after light exposure also had reduced immunoreactivity when stored in the dark, as early as day 3. Eight markers (Bartonella spp, CD11d, high molecular weight cytokeratins, feline coronavirus, GATA-4, insulin, p63, progesterone receptor) had minimal decrease in immunoreactivity, regardless of treatment. In conclusion, light-induced antigen decay (tissue section aging) is antigen dependent and could explain unexpectedly weak or negative immunohistochemical reactions in stored paraffin sections. PMID:23435571

  18. Integrated Optical Voltage Probe

    NASA Astrophysics Data System (ADS)

    Cordero-Iannarella, R. F.; Yao, S. K.; Thaniyavarn, S.; Findakly, T.; Hayward, G.; Chen, B.

    1983-11-01

    We have designed and tested a guided wave optical modulator for applications as an integrated optical voltage probe. This voltage probe consists of an injection laser diode (ILD) connected to a stress-induced polarization preserving fiber, an electro-optic coupled-channel waveguide modulator, a graded-index multimode fiber for the return optical signal, and an electronics box containing the necessary electronics for the driving of the ILD source and the detection of the return signal. The electronics box can be physically separated from the ILD source and the fiber-modulator assemblies for ease of installation in the field. The ILD and modulator assemblies are ruggedized and the fibers are cabled. This probe has been tested in the frequency range 10 kHz-200 MHz and at a dynamic range of 40 dB at 200 MHz bandwidth.

  19. High Voltage Seismic Generator

    NASA Astrophysics Data System (ADS)

    Bogacz, Adrian; Pala, Damian; Knafel, Marcin

    2015-04-01

    This contribution describes the preliminary result of annual cooperation of three student research groups from AGH UST in Krakow, Poland. The aim of this cooperation was to develop and construct a high voltage seismic wave generator. Constructed device uses a high-energy electrical discharge to generate seismic wave in ground. This type of device can be applied in several different methods of seismic measurement, but because of its limited power it is mainly dedicated for engineering geophysics. The source operates on a basic physical principles. The energy is stored in capacitor bank, which is charged by two stage low to high voltage converter. Stored energy is then released in very short time through high voltage thyristor in spark gap. The whole appliance is powered from li-ion battery and controlled by ATmega microcontroller. It is possible to construct larger and more powerful device. In this contribution the structure of device with technical specifications is resented. As a part of the investigation the prototype was built and series of experiments conducted. System parameter was measured, on this basis specification of elements for the final device were chosen. First stage of the project was successful. It was possible to efficiently generate seismic waves with constructed device. Then the field test was conducted. Spark gap wasplaced in shallowborehole(0.5 m) filled with salt water. Geophones were placed on the ground in straight line. The comparison of signal registered with hammer source and sparker source was made. The results of the test measurements are presented and discussed. Analysis of the collected data shows that characteristic of generated seismic signal is very promising, thus confirms possibility of practical application of the new high voltage generator. The biggest advantage of presented device after signal characteristics is its size which is 0.5 x 0.25 x 0.2 m and weight approximately 7 kg. This features with small li-ion battery makes constructed device very mobile. The project is still developing.

  20. High voltage pulse conditioning

    DOEpatents

    Springfield, Ray M. (Sante Fe, NM); Wheat, Jr., Robert M. (Los Alamos, NM)

    1990-01-01

    Apparatus for conditioning high voltage pulses from particle accelerators in order to shorten the rise times of the pulses. Flashover switches in the cathode stalk of the transmission line hold off conduction for a determinable period of time, reflecting the early portion of the pulses. Diodes upstream of the switches divert energy into the magnetic and electrostatic storage of the capacitance and inductance inherent to the transmission line until the switches close.

  1. Low-voltage polyphasic circuits

    NASA Astrophysics Data System (ADS)

    Baird, William H.; Jaynes, Michael L.

    2010-05-01

    Experimentation with polyphasic voltages is greatly simplified when microcontrollers are used to generate multiple square waves with fixed phase offsets. Each square wave is sent through a simple second-order Sallen-Key filter to produce an approximately sinusoidal voltage signal. The microcontroller allows the reproduction of split-phase and three-phase voltage relationships, mirroring those commonly distributed on the North American power grid, at safe voltage levels.

  2. High voltage variable diameter insulator

    DOEpatents

    Vanecek, David L. (Martinez, CA); Pike, Chester D. (Pinole, CA)

    1984-01-01

    A high voltage feedthrough assembly (10) having a tubular insulator (15) extending between the ground plane ring (16) and the high voltage ring (30). The insulator (15) is made of Pyrex and decreases in diameter from the ground plane ring (16) to the high voltage ring (30), producing equipotential lines almost perpendicular to the wall (27) of the insulator (15) to optimize the voltage-holding capability of the feedthrough assembly (10).

  3. Evaluation of Solvita compost stability and maturity tests for assessment of quality of end-products from mixed latrine style compost toilets.

    PubMed

    Hill, Geoffrey B; Baldwin, Susan A; Vinnerås, Bjorn

    2013-07-01

    It is challenging and expensive to monitor and test decentralized composting toilet systems, yet critical to prevent the mismanagement of potentially harmful and pathogenic end-product. Recent studies indicate that mixed latrine composting toilets can be inhibited by high ammonia content, a product of urea hydrolysis. Urine-diverting vermicomposting toilets are better able to accomplish the goals of remote site human waste management by facilitating the consumption of fecal matter by earthworms, which are highly sensitive to ammonia. The reliability of Solvita compost stability and maturity tests were evaluated as a means of determining feedstock suitability for vermicomposting (ammonia) and end-product stability/completeness (carbon dioxide). A significant linear regression between Solvita ammonia and free ammonia gas was found. Solvita ranking of maturity did not correspond to ranking assigned by ammonium:nitrate standards. Solvita ammonia values 4 and 5 contained ammonia levels below earthworm toxicity limits in 80% and 100% of samples respectively indicative of their use in evaluating feedstock suitability for vermicomposting. Solvita stability tests did not correlate with carbon dioxide evolution tests nor ranking of stability by the same test, presumably due to in situ inhibition of decomposition and microbial respiration by ammonia which were reported by the Solvita CO2 test as having high stability values. PMID:23647950

  4. Charge-pump voltage converter

    DOEpatents

    Brainard, John P. (Albuquerque, NM); Christenson, Todd R. (Albuquerque, NM)

    2009-11-03

    A charge-pump voltage converter for converting a low voltage provided by a low-voltage source to a higher voltage. Charge is inductively generated on a transfer rotor electrode during its transit past an inductor stator electrode and subsequently transferred by the rotating rotor to a collector stator electrode for storage or use. Repetition of the charge transfer process leads to a build-up of voltage on a charge-receiving device. Connection of multiple charge-pump voltage converters in series can generate higher voltages, and connection of multiple charge-pump voltage converters in parallel can generate higher currents. Microelectromechanical (MEMS) embodiments of this invention provide a small and compact high-voltage (several hundred V) voltage source starting with a few-V initial voltage source. The microscale size of many embodiments of this invention make it ideally suited for MEMS- and other micro-applications where integration of the voltage or charge source in a small package is highly desirable.

  5. Intermediate state trapping of a voltage sensor

    PubMed Central

    Lacroix, Jérôme J.; Pless, Stephan A.; Maragliano, Luca; Campos, Fabiana V.; Galpin, Jason D.; Ahern, Christopher A.; Roux, Benoît

    2012-01-01

    Voltage sensor domains (VSDs) regulate ion channels and enzymes by undergoing conformational changes depending on membrane electrical signals. The molecular mechanisms underlying the VSD transitions are not fully understood. Here, we show that some mutations of I241 in the S1 segment of the Shaker Kv channel positively shift the voltage dependence of the VSD movement and alter the functional coupling between VSD and pore domains. Among the I241 mutants, I241W immobilized the VSD movement during activation and deactivation, approximately halfway between the resting and active states, and drastically shifted the voltage activation of the ionic conductance. This phenotype, which is consistent with a stabilization of an intermediate VSD conformation by the I241W mutation, was diminished by the charge-conserving R2K mutation but not by the charge-neutralizing R2Q mutation. Interestingly, most of these effects were reproduced by the F244W mutation located one helical turn above I241. Electrophysiology recordings using nonnatural indole derivatives ruled out the involvement of cation-? interactions for the effects of the Trp inserted at positions I241 and F244 on the channel’s conductance, but showed that the indole nitrogen was important for the I241W phenotype. Insight into the molecular mechanisms responsible for the stabilization of the intermediate state were investigated by creating in silico the mutations I241W, I241W/R2K, and F244W in intermediate conformations obtained from a computational VSD transition pathway determined using the string method. The experimental results and computational analysis suggest that the phenotype of I241W may originate in the formation of a hydrogen bond between the indole nitrogen atom and the backbone carbonyl of R2. This work provides new information on intermediate states in voltage-gated ion channels with an approach that produces minimum chemical perturbation. PMID:23183699

  6. Development of an in vitro liquid chromatography-mass spectrometry method to evaluate stereo and chemical stability of new drug candidates employing immobilized artificial membrane column.

    PubMed

    Cannazza, Giuseppe; Battisti, Umberto M; Carrozzo, Marina M; Cazzato, Addolorata S; Braghiroli, Daniela; Parenti, Carlo; Troisi, Luigino

    2014-10-10

    A stopped-flow HPLC method was developed to evaluate configurational and chemical stability of pharmaceutical compounds employing immobilized artificial membranes (IAM) column to simulate conditions that pharmaceutical compounds will meet in vivo. The method was applied to recent developed chiral 5-arylbenzothiadiazine derivatives possessing high positive allosteric modulatory (PAM) activity on AMPA receptor. In particular the stopped-flow HPLC method developed used a chiral column to separate single enantiomer of the compounds that are forced into an IAM column where configurational and chemical stability was evaluated in simulated gastrointestinal fluids (pH 1.2 and 6.8 at 37.5 °C) to simulate in vivo conditions. The results were compared to those obtained by dynamic and off-column methods to evaluate the effects of stationary phases on kinetic constant of enantiomerization and hydrolysis. The results suggested that the phospholipids environment of IAM stationary phases, which mimes biological membrane, greatly influence the hydrolysis process increasing the chemical stability of tested compounds while no influence on enantiomerization kinetic was observed. Therefore it is possible to suppose that 5-arylbenzothiadiazine derivatives should not hydrolysed in vivo while they should rapidly racemized in aqueous solvents. The method could represents a rapid and value tool to predict chemical and configurational stability of new chemical entities to decrease the number of animal studies. PMID:24935265

  7. Evaluation of the longitudinal stability and control characteristics of a mixed-flow remote-lift STOVL aircraft in transition and hover

    NASA Technical Reports Server (NTRS)

    Engelland, Shawn A.

    1991-01-01

    An evaluation of the longitudinal stability and control characteristics of a mixed-flow remote-lift (MFRL) STOVL aircraft in the powered-lift portion of the flight envelope is presented. A stabilization and command augmentation system was implemented on the MFRL aircraft to meet the requirements for satisfactory flying qualities. The pitch portion of this control system uses a state-rate feedback implicit model following controller to achieve the desired flying qualities and to suppress the effects of external variations and disturbances in the aircrafts characteristics over the low speed envelope.

  8. Frequency to Voltage Converter Analog Front-End Prototype

    NASA Technical Reports Server (NTRS)

    Mata, Carlos; Raines, Matthew

    2012-01-01

    The frequency to voltage converter analog front end evaluation prototype (F2V AFE) is an evaluation board designed for comparison of different methods of accurately extracting the frequency of a sinusoidal input signal. A configurable input stage is routed to one or several of five separate, configurable filtering circuits, and then to a configurable output stage. Amplifier selection and gain, filter corner frequencies, and comparator hysteresis and voltage reference are all easily configurable through the use of jumpers and potentiometers.

  9. Evaluation of Colloidal Stability and Ecotoxicity of Metal-based Nanoparticles in the Aquatic and Terrestrial Systems

    NASA Astrophysics Data System (ADS)

    Pokhrel, Lok Raj

    Intrinsic to the many nano-enabled products are atomic-size multifunctional engineered nanomaterials, which upon release contaminate the environments, raising considerable health and safety concerns. This Ph.D. dissertation is designed to investigate (i) whether metals or oxide nanoparticles are more toxic than ions, and if MetPLATE(TM) bioassay is applicable as a rapid nanotoxicity screening tool; (ii) how variable water chemistry (dissolved organic carbon (DOC), pH, and hardness) and organic compounds (cysteine, humic acid, and trolox) modulate colloidal stability, ion release, and aquatic toxicity of silver nanoparticles (AgNP); and (iii) the developmental responses of crop plants exposed to Ag- or ZnO- (zinc oxide) nanoparticles. Results suggest that the MetPLATE can be considered a high-throughput screening tool for rapid nanotoxicity evaluation. Detectable changes in the colloidal diameter, surface charge, and plasmonic resonance revealed modulating effects of variable water chemistry and organic ligands on the particle stability, dissolution, and toxicity of AgNPs against Escherichia coli or Daphnia magna. Silver dissolution increased as a function of DOC concentrations but decreased with increasing hardness, pH, cysteine, or trolox levels. Notably, the dissociated Ag+ was inadequate to explain AgNP toxicity, and that the combined effect of AgNPs and dissolved Ag+ under each ligand treatment was lower than of AgNO 3. Significant attenuation by trolox signifies an oxidative stress-mediated AgNP toxicity; its inability to attenuate AgNO3 toxicity, however, negates oxidative stress as Ag+ toxicity mechanism, and that cysteine could effectively quench free Ag+ to alleviate AgNO 3 toxicity in D. magna. Surprisingly, DOC-AgNPs complex that apparently formed at higher DOC levels might have led daphnids filter-feed on aggregates, potentially elevating internal dose, and thus higher mortality. Maize root anatomy showed differential alterations upon exposure to AgNPs, ZnONPs, or their ions. Overall, various metal-based nanoparticles revealed lower toxicity than their ions against multiple organisms. This study showed that particle size, surface properties, and ion release kinetics of AgNPs modify following release into aquatic environment, suggesting potential implications to ecosystem health and functions, and that caution be applied when extending one species toxicity results to another because obvious differences in organism biology---supporting species sensitivity paradigm---can significantly alter nanoparticle or ionic toxicity.

  10. Simulation of undervoltage load shedding to prevent voltage collapse

    Microsoft Academic Search

    M. Klaric; I. Kuzle; T. Tomisa

    2005-01-01

    Recent blackouts in USA, Italy and London discovered problems with systems in operation near to their limits. After deregulation of power systems in industrialized countries, large problems with voltage stability incurred due to the larger and larger amounts of power transmitted to larger and larger distances. Systems often work on their limits and single contingency is sometimes enough to cause

  11. Undervoltage load shedding using global voltage collapse index

    Microsoft Academic Search

    M. Klaric; I. Kuzle; S. Tesnjak

    2004-01-01

    Increasingly higher demand in power created problems in power system operation since the growth of the transmission system is restricted. System often function close to their stability limits and sometimes loads need to be shed in order to prevent system from collapsing. In this paper one undervoltage load shedding (UVLS) method to prevent voltage collapse is presented. This method is

  12. Head stabilization measurements as a potential evaluation tool for comparison of persons with TBI and vestibular dysfunction with healthy controls.

    PubMed

    Sessoms, Pinata H; Gottshall, Kim R; Sturdy, Jordan; Viirre, Erik

    2015-03-01

    A large percentage of persons with traumatic brain injury incur some type of vestibular dysfunction requiring vestibular physical therapy. These injuries may affect the natural ability to stabilize the head while walking. A simple method of utilizing motion capture equipment to measure head movement while walking was used to assess improvements in head stabilization of persons undergoing computerized vestibular physical therapy and virtual reality training for treatment of their vestibular problems. Movement data from the head and sacrum during gait were obtained over several visits and then analyzed to determine improved oscillatory head movement relative to the sacrum. The data suggest that, over time with treatment, head stabilization improves and moves toward a pattern similar to that of a healthy control population. This simple analysis of measuring head stability could be transferred to smaller, portable systems that are easily utilized to measure head stability during gait for use in gait assessment and physical therapy training. PMID:25747644

  13. Evaluation of Nucleic Acid Stabilization Products for Ambient Temperature Shipping and Storage of Viral RNA and Antibody in a Dried Whole Blood Format.

    PubMed

    Dauner, Allison L; Gilliland, Theron C; Mitra, Indrani; Pal, Subhamoy; Morrison, Amy C; Hontz, Robert D; Wu, Shuenn-Jue L

    2015-07-01

    Loss of sample integrity during specimen transport can lead to false-negative diagnostic results. In an effort to improve upon the status quo, we used dengue as a model RNA virus to evaluate the stabilization of RNA and antibodies in three commercially available sample stabilization products: Whatman FTA Micro Cards (GE Healthcare Life Sciences, Pittsburgh, PA), DNAst?ble Blood tubes (Biom?trica, San Diego, CA), and ViveST tubes (ViveBio, Alpharetta, GA). Both contrived and clinical dengue-positive specimens were stored on these products at ambient temperature or 37°C for up to 1 month. Antibody and viral RNA levels were measured by enzyme-linked immunosorbent assay (ELISA) and quantitative reverse transcription polymerase chain reaction (qRT-PCR) assays, respectively, and compared with frozen unloaded controls. We observed reduced RNA and antibody levels between stabilized contrived samples and frozen controls at our earliest time point, and this was particularly pronounced for the FTA cards. However, despite some time and temperature dependent loss, a 94.6-97.3% agreement was observed between stabilized clinical specimens and their frozen controls for all products. Additional considerations such as cost, sample volume, matrix, and ease of use should inform any decision to incorporate sample stabilization products into a diagnostic testing workflow. We conclude that DNAst?ble Blood and ViveST tubes are useful alternatives to traditional filter paper for ambient temperature shipment of clinical specimens for downstream molecular and serological testing. PMID:25940193

  14. Effect of remote-signalling leads on intrinsically safe direct voltage circuits

    Microsoft Academic Search

    F. Schebsdat

    1978-01-01

    The capacitive ignition stability of a conductor is discussed in terms of increasing the length of conductors used in explosion endangered areas. Also, increasing the operating voltage of conductors is considered.

  15. Comparisons of Three Control Schemes for Adaptive Voltage Position (AVP) Droop for VRMs Applications

    Microsoft Academic Search

    Martin Lee; Dan Chen; Chih-Wen Liu; Kevin Huang; Eddie Tseng; Ben Tai

    2006-01-01

    Based on small-signal models, comparisons were made for three commonly-used control schemes for adaptive voltage position for VRM applications. Performances compared include output impedance, control stability, and audio susceptibility. \\

  16. Multilevel conversion: high voltage choppers and voltage-source inverters

    Microsoft Academic Search

    T. A. Meynard; H. Foch

    1992-01-01

    The authors discuss high-voltage power conversion. Conventional series connection and three-level voltage source inverter techniques are reviewed and compared. A novel versatile multilevel commutation cell is introduced: it is shown that this topology is safer and more simple to control, and delivers purer output waveforms. The authors show how this technique can be applied to either choppers or voltage-source inverters

  17. New techniques to speed up voltage collapse computations using tangent vectors

    Microsoft Academic Search

    A. C. Z. de Souza; C. A. Canizares; V. H. Quintana

    1997-01-01

    This paper discusses various methods based on power network partitioning and voltage stability indices to accelerate the computation of voltage collapse points using continuation techniques. Partitioning methods derived from right eigenvector and tangent vector information are thoroughly studied, identifying limitations and probable application areas; a mixed partition-reduction technique is then proposed to reduce computational burden. Also, tangent vectors are used

  18. VOLTAGE COLLAPSE AND TRANSIENT ENERGY FUNCTION ANALYSES OF AC\\/DC SYSTEMS

    Microsoft Academic Search

    Claudio A. Canizares

    1991-01-01

    Abstract This thesis presents a thorough analysis of saddle-node bifurcations for power system dynamic models, including a third order representation of high voltage direct current (HVDC) transmission, classic ac generator dynamics with reactive flows, and volt- age and frequency dependent load models. Extensions of the Point of Collapse and Continuation methods, initially used in ac system voltage stability studies, are

  19. Geomorphic Assessment Approach to Evaluate Stream Channel Stability for Regions of Illinois, Case Study: Southern Illinois Region

    NASA Astrophysics Data System (ADS)

    Keefer, L. L.

    2004-12-01

    An array of different geomorphic assessment approaches for evaluating stream-channel stability is being utilized throughout the country to meet the demands of resource managers interested in stream channel restoration and management to reduce erosion and improve stream habitat. Over the last century, most of the Illinois landscape has experienced intensive land use changes which have contributed to stream channel instability. Stream channels in Illinois have adjusted to these changes either by increasing lateral rates of migration, downstream translation of meanders, widening, or development of headward retreat of knickpoints, depending on the region of the state. Illinois can be divided into at least four regions based on prevailing physiographic features and style of channel adjustment. Also, channel response in most of these regions tend to be more subtle than the dramatic response characteristics of streams in the Coastal Plains, mountain environments, and the desert southwest for which other geomorphic approaches have been developed. The observed magnitude and type of channel response are related to topography of the bedrock surface and extent and morphology of several glacial periods, which carry local significance for stream management. Given that geomorphic assessments for stream restoration require non-trivial professional, time, and financial resources, the development of approaches for Illinois regional conditions are more beneficial. A geomorphic assessment approach is being developed by adapting methods from existing process-based approaches utilized around the United States. A case-study was performed in the Big Creek watershed of the Cache River Basin for the southern Illinois region. This region was selected first because it exhibited dramatic channel responses to disturbances and had an extensive hydrologic, sediment, and land management record. This adapted approach includes systematic data collection protocols for characterization leading to an evaluation of the fluvial system for the purpose of determining past watershed and channel conditions, current geomorphic character, and potential for future channel adjustments using modest time and financial resources. The performance of this approach in the southern Illinois region and future development for other Illinois regions will be presented.

  20. Variable Speed Wind Turbines for Power System Stability Enhancement

    Microsoft Academic Search

    Nayeem Rahmat Ullah; Torbjrn Thiringer

    2007-01-01

    This paper investigates possible improvements in grid voltage stability and transient stability with wind energy converter units using modified P\\/Q control. The voltage source converter (VSC) in modern variable speed wind turbines is utilized to achieve this enhancement. The findings show that using only available hardware for variable-speed turbines improvements could be obtained in all cases. Moreover, it was found

  1. A stability model for the advanced series compensator (ASC)

    Microsoft Academic Search

    S. G. Jalali; R. A. Hedin; M. Pereira; K. Sadek

    1996-01-01

    This paper develops an accurate and general stability model for the ASC. The model is valid for both the capacitive and inductive regions of the ASC operation. It is accurate in that the instantaneous voltage and current waveforms and also the fundamental component of the capacitor voltage (needed for stability) are determined every half-cycle by solving the differential equations of

  2. Low Voltage Beam Experiments on the PLIA.

    NASA Astrophysics Data System (ADS)

    Coleman, J.; Briggs, R.

    2005-10-01

    A new accelerator concept called the Pulse-Line Ion Accelerator (PLIA) has been developed. The PLIA operates as a transmission line with pulsed power sources generating a ramped traveling voltage wave on a helical coil. The oil dielectric helix has the ability to accelerate ion bunches to energies much greater than the peak applied voltage and over distances much larger than the ramp length. Low voltage beam experiments ranging from 10-80 kV have begun on the 1-m PLIA test section to verify the ability to accelerate an ion bunch and to investigate breakdown issues. Short-pulsed, pencil-like beams with energy ranges of 200-400 keV have been used for the acceleration experiments. Discharge issues have been addressed and evaluated for possible solutions. A semi-conductive chromium oxide film with a low secondary emission coefficient will be tested for elimination of the discharge. It is expected that the discharge issues will be resolved and beam experiments with high voltages will commence. Different acceleration scenarios will be examined relative to the axial focusing requirements. Experimental results and possible solutions for the elimination of the discharge will be described. (This work was supported by DOE under Contract No. DE-AC02-05CH11231).

  3. Quantitative Evaluation of Colloidal Stability of Antibody Solutions using PEG-Induced Liquid-Liquid Phase Separation

    E-print Network

    Benedek, George B.

    pathways including crystallization, colloidal aggregation, and liquid-liquid phase separation (LLPS) can. KEYWORDS: antibody, PEG, liquid-liquid phase separation, colloidal stability, binding energy 1 of protein condensation such as crystallization, aggregation, gelation, and liquid-liquid phase separation

  4. Evaluating Chemical Reactivity And Mechanical Stability Of Nano Palladized Iron Embedded In Activated Carbon On Dechlorination Of Polychlorinated Biphenyls

    EPA Science Inventory

    Remediation of contaminated sites with hydrophobic organic compounds such as polychlorinated biphenyls (PCBs) remains a scientific and technical challenge. The high stability, low aqueous solubility, and high organic affinity of PCBs make them difficult to treat. Many physical,...

  5. Rheology and stability of SRC residual fuel oils - storage evaluation. SRC1 quarterly technical report, October-December 1982. Supplement

    Microsoft Academic Search

    Tewari

    1984-01-01

    In Air Products ongoing study to characterize the rheology and stability of various SRC residual oils, single-phase blends of 50 wt % HSRC and TSL SRC in 1:1 mixtures of 1st- and 2nd-stage process solvents were subjected to storage stability tests at 150°F in nitrogen and air atmospheres. Using viscosity as an indicator, it was observed that the blends studied

  6. Three-dimensional stability evaluation of landslides and a sliding process simulation using a new geographic information systems component

    Microsoft Academic Search

    Mowen Xie; Tetsuro Esaki; Guoyun Zhou; Yasuhiro Mitani

    2003-01-01

    In this paper, based on a column-based three-dimensional (3-D) slope-stability analysis model, a new geographic information systems (GIS) grid-based 3-D deterministic model is developed. Assuming the initial slip as the lower part of an ellipsoid, the identification of the 3-D critical slip surface in the 3-D slope-stability analysis is performed by means of a minimization of the 3-D safety factor

  7. Stability of CIGS Solar Cells and Component Materials Evaluated by a Step-Stress Accelerated Degradation Test Method: Preprint

    SciTech Connect

    Pern, F. J.; Noufi, R.

    2012-10-01

    A step-stress accelerated degradation testing (SSADT) method was employed for the first time to evaluate the stability of CuInGaSe2 (CIGS) solar cells and device component materials in four Al-framed test structures encapsulated with an edge sealant and three kinds of backsheet or moisture barrier film for moisture ingress control. The SSADT exposure used a 15oC and then a 15% relative humidity (RH) increment step, beginning from 40oC/40%RH (T/RH = 40/40) to 85oC/70%RH (85/70) as of the moment. The voluminous data acquired and processed as of total DH = 3956 h with 85/70 = 704 h produced the following results. The best CIGS solar cells in sample Set-1 with a moisture-permeable TPT backsheet showed essentially identical I-V degradation trend regardless of the Al-doped ZnO (AZO) layer thickness ranging from standard 0.12 ?m to 0.50 ?m on the cells. No clear 'stepwise' feature in the I-V parameter degradation curves corresponding to the SSADT T/RH/time profile was observed. Irregularity in I-V performance degradation pattern was observed with some cells showing early degradation at low T/RH < 55/55 and some showing large Voc, FF, and efficiency degradation due to increased series Rs (ohm-cm2) at T/RH ? 70/70. Results of (electrochemical) impedance spectroscopy (ECIS) analysis indicate degradation of the CIGS solar cells corresponded to increased series resistance Rs (ohm) and degraded parallel (minority carrier diffusion/recombination) resistance Rp, capacitance C, overall time constant Rp*C, and 'capacitor quality' factor (CPE-P), which were related to the cells? p-n junction properties. Heating at 85/70 appeared to benefit the CIGS solar cells as indicated by the largely recovered CPE-P factor. Device component materials, Mo on soda lime glass (Mo/SLG), bilayer ZnO (BZO), AlNi grid contact, and CdS/CIGS/Mo/SLG in test structures with TPT showed notable to significant degradation at T/RH ? 70/70. At T/RH = 85/70, substantial blistering of BZO layers on CIGS cell pieces was observed that was not seen on BZO/glass, and a CdS/CIGS sample displayed a small darkening and then flaking feature. Additionally, standard AlNi grid contact was less stable than thin Ni grid contact at T/RH ? 70/70. The edge sealant and moisture-blocking films were effective to block moisture ingress, as evidenced by the good stability of most CIGS solar cells and device components at T/RH = 85/70 for 704 h, and by preservation of the initial blue color on the RH indicator strips. The SSADT experiment is ongoing to be completed at T/RH = 85/85.

  8. Evaluating the Stability of RNA-Seq Transcriptome Profiles and Drug-Induced Immune-Related Expression Changes in Whole Blood

    PubMed Central

    Bowyer, John F.; Tranter, Karen M.; Hanig, Joseph P.; Crabtree, Nathaniel M.; Schleimer, Robert P.; George, Nysia I.

    2015-01-01

    Methods were developed to evaluate the stability of rat whole blood expression obtained from RNA sequencing (RNA-seq) and assess changes in whole blood transcriptome profiles in experiments replicated over time. Expression was measured in globin-depleted RNA extracted from the whole blood of Sprague-Dawley rats, given either saline (control) or neurotoxic doses of amphetamine (AMPH). The experiment was repeated four times (paired control and AMPH groups) over a 2-year span. The transcriptome of the control and AMPH-treated groups was evaluated on: 1) transcript levels for ribosomal protein subunits; 2) relative expression of immune-related genes; 3) stability of the control transcriptome over 2 years; and 4) stability of the effects of AMPH on immune-related genes over 2 years. All, except one, of the 70 genes that encode the 80s ribosome had levels that ranked in the top 5% of all mean expression levels. Deviations in sequencing performance led to significant changes in the ribosomal transcripts. The overall expression profile of immune-related genes and genes specific to monocytes, T-cells or B-cells were well represented and consistent within treatment groups. There were no differences between the levels of ribosomal transcripts in time-matched control and AMPH groups but significant differences in the expression of immune-related genes between control and AMPH groups. AMPH significantly increased expression of some genes related to monocytes but down-regulated those specific to T-cells. These changes were partially due to changes in the two types of leukocytes present in blood, which indicate an activation of the innate immune system by AMPH. Thus, the stability of RNA-seq whole blood transcriptome can be verified by assessing ribosomal protein subunits and immune-related gene expression. Such stability enables the pooling of samples from replicate experiments to carry out differential expression analysis with acceptable power. PMID:26177368

  9. [Method for the evaluation of the stability and usability after opening packages of orally disintegrating tablets: case of amlodipine besilate products].

    PubMed

    Hori, Katsuhito; Yoshida, Naoko; Okumura, Tomonori; Okamura, Yasufumi; Kawakami, Junichi

    2010-08-01

    Orally disintegrating (OD) tablets are widely used in clinical practice. However, drug information on the choice and dispensing based on their stability after opening packages and usability in patients and dispensaries is not sufficient. The aim of this study was to investigate possible evaluation methods of the stability and usability of amlodipine OD tablets. Additives of the brand were changed in April 2009, and therefore the previous and current forms and two generics, current and newly marketed (in November 2009) products of different firms, were used. OD tablets were stored at 25 degrees C and 75% relative humidity for 3 months after opening the packages, and their physicochemical properties were evaluated. Their weight, diameter, thickness, and color difference increased slightly from the initial state. The extent of the change in their hardness, disintegration time, and friability was different among products. These physicochemical changes were acceptable in dispensary practice. Storage after opening the packages did not affect their dissolution rate. The dissolution rate at the initial state of the current brand was slower than that of the previous one. All products used were able to be dispensed by an automatic tablet-packing machine and applied to the so-called simple suspension method for intubational administration. Sensory evaluation tests revealed no major difference in the oral disintegration time, taste, impression, and preference among products. In conclusion, the stability and usability of amlodipine OD tablets used in this study were examined using several methods, and they can be used equivalently from the stability and usability viewpoints. PMID:20686207

  10. Evaluation of the geometric stability and the accuracy potential of digital cameras — Comparing mechanical stabilisation versus parameterisation

    NASA Astrophysics Data System (ADS)

    Rieke-Zapp, D.; Tecklenburg, W.; Peipe, J.; Hastedt, H.; Haig, Claudia

    Recent tests on the geometric stability of several digital cameras that were not designed for photogrammetric applications have shown that the accomplished accuracies in object space are either limited or that the accuracy potential is not exploited to the fullest extent. A total of 72 calibrations were calculated with four different software products for eleven digital camera models with different hardware setups, some with mechanical fixation of one or more parts. The calibration procedure was chosen in accord to a German guideline for evaluation of optical 3D measuring systems [VDI/VDE, VDI/VDE 2634 Part 1, 2002. Optical 3D Measuring Systems-Imaging Systems with Point-by-point Probing. Beuth Verlag, Berlin]. All images were taken with ringflashes which was considered a standard method for close-range photogrammetry. In cases where the flash was mounted to the lens, the force exerted on the lens tube and the camera mount greatly reduced the accomplished accuracy. Mounting the ringflash to the camera instead resulted in a large improvement of accuracy in object space. For standard calibration best accuracies in object space were accomplished with a Canon EOS 5D and a 35 mm Canon lens where the focusing tube was fixed with epoxy (47 ?m maximum absolute length measurement error in object space). The fixation of the Canon lens was fairly easy and inexpensive resulting in a sevenfold increase in accuracy compared with the same lens type without modification. A similar accuracy was accomplished with a Nikon D3 when mounting the ringflash to the camera instead of the lens (52 ?m maximum absolute length measurement error in object space). Parameterisation of geometric instabilities by introduction of an image variant interior orientation in the calibration process improved results for most cameras. In this case, a modified Alpa 12 WA yielded the best results (29 ?m maximum absolute length measurement error in object space). Extending the parameter model with FiBun software to model not only an image variant interior orientation, but also deformations in the sensor domain of the cameras, showed significant improvements only for a small group of cameras. The Nikon D3 camera yielded the best overall accuracy (25 ?m maximum absolute length measurement error in object space) with this calibration procedure indicating at the same time the presence of image invariant error in the sensor domain. Overall, calibration results showed that digital cameras can be applied for an accurate photogrammetric survey and that only a little effort was sufficient to greatly improve the accuracy potential of digital cameras.

  11. Thermal stability of GaAs heteroface solar cells with differing contact materials

    NASA Technical Reports Server (NTRS)

    Friesen, W. J.; Walker, G. H.; Conway, E. J.

    1981-01-01

    GaAlAs/GaAs heteroface solar cells used in space offer advantages of higher operating temperatures and recovery from radiation damage using thermal annealing. Elevated temperature experiments were conducted to evaluate the electrical stability of cells with different contact materials. These experiments indicate that for operation of GaAs heteroface solar cells at elevated temperatures, front contact metals must be carefully chosen. The short circuit current varied by only about 3% for cells with Pd/Ag contacts that were heated to 240 C for a total of 500 hours. However, a total decrease in the open circuit voltage of about 20% was observed for these cells. After heating cells to 400 C, large changes in open circuit voltage were observed for cells with Pd/Ag, Pd/Au, Pd, Ag, and Ti contacts; however, preliminary results indicate more stable open circuit voltages for cells with Au, Cr, Zn, and Cr/Au contacts.

  12. Accurate voltage phasor measurement in a series-compensated network

    SciTech Connect

    Lambert, J.; McNabb, D. (Hydro-Quebec, Montreal, Quebec (Canada)); Phadke, A.G. (Virginia Polytechnic Inst. and State Univ., Blacksburg, VA (United States))

    1994-01-01

    This paper describes the feasibility studies concerning an accurate voltage phasor measurement in series-compensated network undergoing large disturbances. The principal modes of distortions in such a network are described. Some of these modes are changing with the fundamental frequency. The phasor evaluation is based on a new digital filter approach in which the fundamental frequency is estimated using a least-square algorithm. The need to have special potential (voltage) transformers is also discussed. This approach would be used in a shunt reactor switching scheme for an overall voltage control of a transmission network.

  13. High voltage conductors in spacecraft

    Microsoft Academic Search

    Daniel Hastings

    1993-01-01

    Future solar arrays are being designed for much higher voltages in order to meet high power demands at low currents. Unfortunately, negatively biased high voltage solar cells have been observed to arc when exposed to the low earth orbit plasma environment. Analytical and numerical models of this arcing phenomenon on conventional solar cells have been developed which show excellent agreement

  14. Nonlinear electrokinetics at large voltages

    E-print Network

    Bazant, Martin Z.

    The classical theory of electrokinetic phenomena assumes a dilute solution of point-like ions in chemical equilibrium with a surface whose double-layer voltage is of order the thermal voltage, kBT/e=25 mV. In nonlinear ...

  15. Temperature controlled high voltage regulator

    DOEpatents

    Chiaro, Jr., Peter J. (Clinton, TN); Schulze, Gerald K. (Knoxville, TN)

    2004-04-20

    A temperature controlled high voltage regulator for automatically adjusting the high voltage applied to a radiation detector is described. The regulator is a solid state device that is independent of the attached radiation detector, enabling the regulator to be used by various models of radiation detectors, such as gas flow proportional radiation detectors.

  16. Low-voltage electrooptic deflector

    Microsoft Academic Search

    Yu M Dikaev; Yu L Kopylov; I. M. Kotelyanskii; V. B. Kravchenko

    1981-01-01

    An investigation was made of a low-voltage electrooptic deflector of the blazed grating type. The control voltage was reduced by employing a thin (20 ? ) plate of LiNbO3. The deflector resolved discretely 51 points on application of 6 V per one resolvable point.

  17. Shaft voltages and rotating machinery

    Microsoft Academic Search

    Michael J. Costello

    1993-01-01

    In order to determine whether a machine is experiencing shaft voltage and current problems, recognition of the four types of damage is imperative. The four distinct types of shaft current damage, frosting, spark tracks, pitting, and welding are described. The four shaft voltage sources and their means of generation are discussed in detail. Methods for correction and\\/or elimination of these

  18. Synthesis and pharmacological evaluation of 2, 3-dihydro-3-oxo-4H-thieno[3,4-e][1,2,4]thiadiazine 1,1-dioxides as voltage-dependent calcium channel blockers.

    PubMed

    Arranz, E; Díaz, J A; Vega, S; Campos-Toimil, M; Orallo, F; Cardelús, I; Llenas, J; Fernández, A G

    2000-01-01

    The synthesis of a novel series of 2,3-dihydro-3-oxo-4H-thieno[3, 4-e][1,2,4]thiadiazine 1,1-dioxides and their pharmacological evaluation as drugs with effects on the rat cardiovascular system are described. The compounds under study were synthesized via Curtius rearrangement of appropriate sulfamoylacylazides which, in turn, were prepared from known starting materials. In isolated rat portal vein, these thienothiadiazines, like verapamil and diazoxide, inhibited the spontaneous motility produced by KCl (20 mM). In addition, the new compounds, like verapamil and unlike diazoxide, also exhibited inhibitory effects in the same preparation when the cell membrane was depolarized by an increased extracellular KCl concentration (80 mM) and, consequently, the membrane potential approached a level close to the K(+) equilibrium potential. Further characterization of this inhibitory activity led to the identification of a selective inhibitory effect of the new compounds on KCl (80 mM)-induced 45Ca(2+) uptake in the same vascular tissue. When tested in vivo (anaesthetized normotensive rats), acute administration of verapamil, diazoxide and some of the most in vitro potent compounds in 45Ca(2+) uptake experiments produced a gradual, dose-dependent and sustained decrease in diastolic arterial blood pressure, devoid of cardiac effects. These results suggest that, like verapamil, the cardiovascular effects produced by the new thienothiadiazines seem to be due, at least in part, to a blockade of transmembrane voltage-dependent calcium channels present in vascular smooth muscle cells and not to an activation of ATP-sensitive K(+) channels. Compounds 5b, 5e and 5i have been selected for further studies as antihypertensive agents. PMID:10960192

  19. GAS DISCHARGE SWITCH EVALUATION FOR RHIC BEAM ABORT KICKER APPLICATION.

    SciTech Connect

    ZHANG,W.; SANDBERG,J.; SHELDRAKE,R.; PIRRIE,C.

    2002-06-30

    A gas discharge switch EEV HX3002 is being evaluated at Brookhaven National Laboratory as a possible candidate of RHIC Beam Abort Kicker modulator main switch. At higher beam energy and higher beam intensity, the switch stability becomes very crucial. The hollow anode thyratron used in the existing system is not rated for long reverse current conduction. The reverse voltage arcing caused thyratron hold-off voltage de-rating has been the main limitation of the system operation. To improve the system reliability, a new type of gas discharge switch has been suggested by Marconi Applied Technology for its reverse conducting capability.

  20. Wide-range voltage modulation

    SciTech Connect

    Rust, K.R.; Wilson, J.M.

    1992-06-01

    The Superconducting Super Collider`s Medium Energy Booster Abort (MEBA) kicker modulator will supply a current pulse to the abort magnets which deflect the proton beam from the MEB ring into a designated beam stop. The abort kicker will be used extensively during testing of the Low Energy Booster (LEB) and the MEB rings. When the Collider is in full operation, the MEBA kicker modulator will abort the MEB beam in the event of a malfunction during the filling process. The modulator must generate a 14-{mu}s wide pulse with a rise time of less than 1 {mu}s, including the delay and jitter times. It must also be able to deliver a current pulse to the magnet proportional to the beam energy at any time during ramp-up of the accelerator. Tracking the beam energy, which increases from 12 GeV at injection to 200 GeV at extraction, requires the modulator to operate over a wide range of voltages (4 kV to 80 kV). A vacuum spark gap and a thyratron have been chosen for test and evaluation as candidate switches for the abort modulator. Modulator design, switching time delay, jitter and pre-fire data are presented.

  1. The effect of lithium loadings on anode to the voltage drop during charge and discharge of Li-ion capacitors

    NASA Astrophysics Data System (ADS)

    Cao, W. J.; Greenleaf, M.; Li, Y. X.; Adams, D.; Hagen, M.; Doung, T.; Zheng, J. P.

    2015-04-01

    The IR voltage drop from the anode and cathode of Li-ion capacitors during charge and discharge was studied. Li-ion capacitors were made with activated carbon cathode and hard carbon anode with different loadings of stabilized lithium metal powder (SLMP). It was found that the LICs with high SLMP loadings showed smaller voltage drop than LICs with low SLMP loadings. It was also found that at low SLMP loadings, the IR voltage drops at high cell voltages were smaller than that at low cell voltages; while at high SLMP loadings, small IR voltage drops were obtained for both low and high cell voltages. The electrochemical impedance spectroscopy confirmed that voltage drops are directly related to the internal resistances of Li-ion capacitors.

  2. Effects of stabilizing agents on the development of myricetin nanosuspension and its characterization: an in vitro and in vivo evaluation.

    PubMed

    Hong, Chao; Dang, Yang; Lin, Guobei; Yao, Yashu; Li, Guowen; Ji, Guang; Shen, Hongyi; Xie, Yan

    2014-12-30

    Although myricetin has various pharmacological applications, it shows low oral bioavailability (<10%) in rats due to its poor aqueous solubility. To overcome this issue, myricetin nanosuspensions were developed and the effects of stabilizers were investigated. Based on the particle size and zeta potential, stabilizers soya lecithin, TPGS, HP-?-CD, and/or a combination thereof were used. The prepared nanosuspensions were characterized by scanning electron microscopy (SEM), differential scanning calorimetry (DSC), and X-ray powder diffraction (XRD). The resulting myricetin nanosuspensions contained particles in the size range of 300-500 nm and were physically stable. Myricetin was partially transformed from crystalline to amorphous forms in the presence of different excipients after the nanosizing process. The solubility and in vitro dissolution of all myricetin nanosuspensions were greatly increased compared with those of the myricetin powder. Consequently, the relative bioavailability in rats were 2.44, 3.57, 1.61, and 2.96 for nanosuspensions stabilized with TPGS, soya lecithin, soya lecithin+TPGS, and HP-?-CD+TPGS, respectively, relative to that of the coarse myricetin. This research demonstrated that nanosuspension is a promising strategy for delivering poor water-soluble drugs such as myricetin and that stabilizers played a critical role in the formulation design of myricetin nanosuspensions. PMID:25445518

  3. J-integral elastic plastic fracture mechanics evaluation of the stability of cracks in nuclear reactor pressure vessels

    SciTech Connect

    Gomez, M. P.; McMeeking, R. M.; Parks, D. M.

    1980-06-01

    Contributions were made toward developing a new methodology to assess the stability of cracks in pressure vessels made from materials that exhibit a significant increase in toughness during the early increments of crack growth. It has a wide range of validity from linear elastic to fully plastic behavior.

  4. Chemiluminescence in evaluating thermal oxidative stability of acrylonitrile-butadiene-styrene (ABS) copolymers. III. Emulsion-grade products

    Microsoft Academic Search

    Sunil S. Parikh; Lev Zlatkevich

    1995-01-01

    The thermal oxidative stability of various formulations based on emulsion-grade ABS was studied by the chemiluminescence technique. Emulsion products were found to be essentially less stable than ionic mass polymerization resins. Among the antioxidants studied, Santonox R is clearly more efficient than Irganox 1076 and Irganox 3114, and its superiority is reflected primarily in improved induction period values. The introduction

  5. Evaluation of Mask Soaking Performance in a Thermally Stabilized Vacuum Chamber in an Electron Beam Mask Writer

    Microsoft Academic Search

    Soichiro Mitsui; Kiminobu Akeno; Munehiro Ogasawara; Toru Tojo

    2004-01-01

    A temperature difference between a mask and a writing environment, which occurs during mask loading, is one of the most significant sources of the mask image placement error. The temperature of the mask has to be adjusted in a thermal chamber. To realize a rapid and highly accurate thermal soaking process, we constructed a new thermally stabilized vacuum chamber with

  6. Evaluation of the geometric stability and the accuracy potential of digital cameras — Comparing mechanical stabilisation versus parameterisation

    Microsoft Academic Search

    D. Rieke-Zapp; W. Tecklenburg; J. Peipe; H. Hastedt; Claudia Haig

    2009-01-01

    Recent tests on the geometric stability of several digital cameras that were not designed for photogrammetric applications have shown that the accomplished accuracies in object space are either limited or that the accuracy potential is not exploited to the fullest extent. A total of 72 calibrations were calculated with four different software products for eleven digital camera models with different

  7. EVALUATION OF CONTAMINANT LEACHABILITY FACTORS BY COMPARISON OF TREATABILITY STUDY DATA FOR MULTIPLE SOLIDIFIED/STABILIZED MATERIALS

    EPA Science Inventory

    Solidification/stabilization (S/S) technology is widely used in the treatment of hazardous waste and contaminated soil in the US. In a project sponsored by the US Navy and the USEPA, treatability test data were compiled into a data base listing contaminant concentration and matri...

  8. Understanding Pound-Drever-Hall locking using voltage controlled radio-frequency oscillators: An undergraduate experiment

    E-print Network

    Le Roy, Robert J.

    Understanding Pound-Drever-Hall locking using voltage controlled radio-frequency oscillators techniques using radio-frequency electronics. The primary objective is to frequency stabilize a volt- age is commonly applied to stabilize lasers at optical frequencies. By using only radio- frequency equipment

  9. Flight Evaluation of the Army/NASA Variable Stability Fly-by-Wire Rotorcraft Aircrew Systems Concept Airborne Laboratory (RASCAL) JUH-60A

    NASA Technical Reports Server (NTRS)

    Arterburn, Dave

    2002-01-01

    NASA Ames Research Center and the U.S. Army Aeroflightdynamics Directorate (AFDD) have performed initial flight evaluations of the Research Flight Control System (RFCS) integrated into the Army/NASA Rotorcraft Aircrew Systems Concepts Airborne Laboratory (RASCAL) JUH-60A. The highly modified JUH-6OA Black Hawk helicopter is a full authority, high bandwidth, variable stability, in-flight simulator designed to support development of advanced flight control, sensor, and integrated display and control technologies in a fail safe environment. Preparation for flight test required an extensive hazard analysis and ground testing to ensure proper system operation. A hardware in the loop development facility was utilized to evaluate control law stability following software changes, assess servo hardover upset conditions during manual and monitor disengagements and provide pilot familiarization of test techniques and software changes prior to flight. First engagement of the RFCS was conducted on 31 Aug 2001. RFCS transfer system operation, envelope expansion and a limited rate monitor evaluation have been completed with low bandwidth and model following control laws.

  10. Research on UnderVoltage Load-Shedding to Prevent Voltage Collapse of Electric Power System

    Microsoft Academic Search

    Jingjing Zhang; Ming Ding; Shenghu Li

    2009-01-01

    A voltage collapse is defined as the process by which voltage instability leads to a very low voltage profile in a significant part of the system. Under-voltage load-shedding is an efficient scheme to prevent voltage collapse. The paper analyses the mechanism of under-voltage load-shedding preventing voltage collapse, compares distributed load-shedding scheme with centralized scheme, introduces under-voltage load-shedding scheme employment at

  11. Power-MOSFET Voltage Regulator

    NASA Technical Reports Server (NTRS)

    Miller, W. N.; Gray, O. E.

    1982-01-01

    Ninety-six parallel MOSFET devices with two-stage feedback circuit form a high-current dc voltage regulator that also acts as fully-on solid-state switch when fuel-cell out-put falls below regulated voltage. Ripple voltage is less than 20 mV, transient recovery time is less than 50 ms. Parallel MOSFET's act as high-current dc regulator and switch. Regulator can be used wherever large direct currents must be controlled. Can be applied to inverters, industrial furnaces photovoltaic solar generators, dc motors, and electric autos.

  12. Low voltage nonprimary explosive detonator

    DOEpatents

    Dinegar, Robert H. (Los Alamos, NM); Kirkham, John (Newbury, GB2)

    1982-01-01

    A low voltage, electrically actuated, nonprimary explosive detonator is disclosed wherein said detonation is achieved by means of an explosive train in which a deflagration-to-detonation transition is made to occur. The explosive train is confined within a cylindrical body and positioned adjacent to low voltage ignition means have electrical leads extending outwardly from the cylindrical confining body. Application of a low voltage current to the electrical leads ignites a self-sustained deflagration in a donor portion of the explosive train which then is made to undergo a transition to detonation further down the train.

  13. What are standardized equations for acceptance of hipot tests and for voltage drop?

    Microsoft Academic Search

    M. O. Durham; Robert A. Durham; D. Anderson

    1998-01-01

    Long power cables and large electric machines require different application techniques from most electrical wiring. The first topic discussed is evaluation of insulation for continued use. The second area is selection of conductor size considering temperature and voltage drop. The hi-pot evaluation is primarily a maintenance function, while the voltage drop procedure is primarily a design practice. For the first

  14. Axon voltage-clamp simulations. I. Methods and tests.

    PubMed Central

    Moore, J W; Ramón, F; Joyner, R W

    1975-01-01

    This is the first in a series of four papers in which we present the numerical simulation of the application of the voltage clamp technique to excitable cells. In this paper we describe the application of the Crank-Nicolson (1947) method for the solution of the parabolic partial differential equations that describe a cylindrical cell in which the ionic conductances are functions of voltage and time (Hodgkin and Huxley, 1952). This method is compared with other methods in terms of accuracy and speed of solution for a propagated action potential. In addition, differential equations representing a simple voltage-clamp electronic circuit are presented. Using the voltage clamp circuit equations, we simulate the voltage clamp of a single isopotential membrane patch and show how the parameters of the circuit affect the transient response of the patch to a step change in the control potential.The stimulation methods presented in this series of papers allow the evaluation of voltage clamp control of an excitable cell or a syncytium of excitable cells. To the extent that membrane parameters and geometrical factors can be determined, the methods presented here provide solutions for the voltage profile as a function of time. PMID:1174640

  15. Saving Megawatts with Voltage Optimization 

    E-print Network

    Wilson, T.; Bell, D.

    2010-01-01

    that had been installed at several electric utility distribution substations in the U.S. and Canada. These systems, being operated in Conservation Voltage Regulation mode, have provided significant energy conservation where they have been installed...

  16. Voltage tunable microwave ferrite resonator

    E-print Network

    Oates, Daniel E.

    A novel method of implementing a tunable resonator using an applied voltage is presented. Stress is used to tune a microstrip resonator fabricated on a polycrystalline ferrite substrate. The stress was applied either ...

  17. Voltage-Gated K Channels

    NSDL National Science Digital Library

    Clay M. Armstrong (University of Pennsylvania; Department of Physiology REV)

    2003-06-24

    This STKE review discusses the structural basis for the selectivity and voltage-dependent gating of the voltage-gated K channel. Ion channels and the electrical properties they confer on cells are involved in every human characteristic that distinguishes us from the stones in a field. Every perception, thought, movement, and heartbeat depends on electrical signals generated by the activity of ion channels. These membrane proteins must show specificity for particular ionic species, facilitate the rapid movement of the selected ions across the cell membrane, and open and shut (gate) in response to appropriate signals. Such gating signals may include changes in the voltage across the cell membrane, mechanical deformation of the membrane, and various chemicals. This review, which focuses on voltage-gated K channels, goes from early views of the relationship between ion channel structure and function to our current picture of how selectivity, conduction, and gating are achieved. This review has eight figures and 56 references.

  18. High voltage solar array experiments

    NASA Technical Reports Server (NTRS)

    Kennerud, K. L.

    1974-01-01

    The interaction between the components of a high voltage solar array and a simulated space plasma is studied to obtain data for the design of a high voltage solar array capable of 15kW at 2 to 16kV. Testing was conducted in a vacuum chamber 1.5-m long by 1.5-m diameter having a plasma source which simulated the plasma conditions existing in earth orbit between 400 nautical miles and synchronous altitude. Test samples included solar array segments pinholes in insulation covering high voltage electrodes, and plain dielectric samples. Quantitative data are presented in the areas of plasma power losses, plasma and high voltage induced damage, and dielectric properties. Limitations of the investigation are described.

  19. Current Controlled Voltage Source (CCVS)

    NSDL National Science Digital Library

    Svoboda, James A.

    This interactive website from professor James A. Svoboda of Clarkson University describes a circuit that contains a Current Controlled Voltage Source (CCVS). The gain of the CCVS can be changed using the scrollbar.

  20. High voltage lightning grounding device

    NASA Technical Reports Server (NTRS)

    Hoffman, R. G.; Peterson, V. S.

    1971-01-01

    Grounding device insertion in wire termination cabinets and terminal block modification prevent lightning-induced high voltage transients from reaching inputs or outputs of solid state instruments and control systems. Installation minimizes wiring confusion and achieves 100 percent protection.

  1. Performance Evaluation and Mathematical Modeling of Nitrogen Reduction in Waste Stabilization Ponds in Conjunction with Other Treatment Systems

    Microsoft Academic Search

    Youngchul Kim; Jaehong Park; Dimosthenis L. Giokas; Triantafyllos A. Albanis

    2004-01-01

    In this study, a widely-recognized nitrogen reduction model of waste stabilization ponds (WSPs) was tested for its universal utility in four different cases including shallow algal ponds (SAPs), WSPs followed by SAPs and water hyacinth ponds, respectively, and WSPs upgrading a secondary effluent. A goodness-of-fit study between measurements and calculated values indicates that it provides a satisfactory description of nitrogen

  2. Stability Criteria and Objective Evaluation of a Driver-Vehicle System for Driving in Lane Change and against Crosswind

    Microsoft Academic Search

    Hiroshi HARADA; Takashi IWASAKI

    1994-01-01

    Stability criteria of driver-vehicle system is derived analytically in typical cases of lane change and straight running against crosswind, assuming that vehicle dynamics are provided as a closed loop system and driver's steering is controlled under a linear preview strategy. On the u(velocity)-Tp(preview time) plane, vehicle design parameters and driver's characteristics can be discussed quantitatively in terms of the effects

  3. Evaluation of the Physical Stability of Zinc Oxide Suspensions Containing Sodium Poly(acrylate) and Sodium Dodecylsulfate

    Microsoft Academic Search

    Malika Chabni; Hadda Bougherra; Hakim Lounici; Toudert Ahmed-Zaïd; Jean-Paul Canselier; Joël Bertrand

    2011-01-01

    The physical stability of zinc oxide (ZnO) aqueous suspensions has been monitored during two months by different methods of investigation. The suspensions were formulated with ZnO at a fixed concentration (5 wt%), sodium poly-(acrylate), as a viscosifier, and sodium dodecylsulfate (SDS), as a wetting agent. The rheological study shows that the suspensions exhibit a non-Newtonian, most often shear-thinning behavior and their

  4. Chemiluminescence in evaluating the thermal oxidative stability of acrylonitrile-butadiene-styrene (ABS) copolymers. II. ABS\\/polycarbonate (PC) blends

    Microsoft Academic Search

    Sunil S. Parikh; Lev Zlatkevich

    1993-01-01

    The thermal oxidative stability of various ABS\\/PC compounds was studied by means of the chemiluminescence technique. Similarly to pure ABS, Irganox 1076 and Irganox MD 1024 perform as moderate antioxidants in ABS\\/PC and (ABS\\/PC + lubricant) blends. Neither Tinuvin 144, Irgaphos 168, nor their mixture affects the durability of the ABS\\/PC blend. At the same time, (Irgaphos 168 + Tinuvin

  5. Bulk Power System Dynamics and Control VI, August 22-27, 2004, Cortina D'Ampezzo, Italy A Probabilistic Approach to Evaluate Security

    E-print Network

    Cañizares, Claudio A.

    and voltage stability theory to determine the total cost of maintaining system security in a market such as the ATC, using this information to define a novel security index. The proposed techniques are applied A Probabilistic Approach to Evaluate Security Costs and Levels in Competitive Electricity Markets E. Warren King

  6. An engineered cover system for mine tailings using a hardpan layer: a solidification/stabilization method for layer and field performance evaluation.

    PubMed

    Ahn, Joo Sung; Song, Hocheol; Yim, Gil-Jae; Ji, Sang Woo; Kim, Jae-Gon

    2011-12-15

    A cover system for mine tailings with a solidified layer (called an engineered hardpan) was developed in this study to reduce water infiltration, acid generation and sulfide oxidation. Hydrated lime and waterglass were used to produce calcium silicate, which can serve as a binder when constructing a hardpan layer. The compressive strength of each solidified/stabilized material was found to be sufficient in the lab, and the amounts of heavy metals were significantly reduced in chemical leaching tests. Various characteristics of tailings may affect the layer's mechanical strength early on, but a long curing period is capable of compensating for these effects. Heavy metals were stabilized as carbonate-bound phases and sulfide minerals were surrounded by calcium silicate matrix, thereby preventing further reaction. To evaluate the field performance of the system, a hardpan layer was installed on top of tailings on a pilot scale. Leachate with high salt content was generated in the tailings layer in the early stages of monitoring, but after approximately 6 months, the objective was achieved as the hardpan layer gradually stabilized. Notably, during the heavy rainfall season of the later monitoring stage, water infiltration was continuously prevented by the system. PMID:21974852

  7. DSC studies to evaluate the impact of bio-oil on cold flow properties and oxidation stability of bio-diesel.

    PubMed

    Garcia-Perez, Manuel; Adams, Thomas T; Goodrum, John W; Das, K C; Geller, Daniel P

    2010-08-01

    This paper describes the use of Differential Scanning Calorimetry (DSC) to evaluate the impact of varying mix ratios of bio-oil (pyrolysis oil) and bio-diesel on the oxidation stability and on some cold flow properties of resulting blends. The bio-oils employed were produced from the semi-continuous Auger pyrolysis of pine pellets and the batch pyrolysis of pine chips. The bio-diesel studied was obtained from poultry fat. The conditions used to prepare the bio-oil/bio-diesel blends as well as some of the fuel properties of these blends are reported. The experimental results suggest that the addition of bio-oil improves the oxidation stability of the resulting blends and modifies the crystallization behavior of unsaturated compounds. Upon the addition of bio-oil an increase in the oxidation onset temperature, as determined by DSC, was observed. The increase in bio-diesel oxidation stability is likely to be due to the presence of hindered phenols abundant in bio-oils. A relatively small reduction in DSC characteristic temperatures which are associated with cold flow properties was also observed but can likely be explained by a dilution effect. PMID:20307976

  8. Application of an asymmetric finite element model of the C2-T1 cervical spine for evaluating the role of soft tissues in stability.

    PubMed

    Erbulut, D U; Zafarparandeh, I; Lazoglu, I; Ozer, A F

    2014-07-01

    Different finite element models of the cervical spine have been suggested for evaluating the roles of ligaments, facet joints, and disks in the stability of cervical spine under sagittal moments. However, no comprehensive study on the response of the full cervical spine that has used a detailed finite element (FE) model (C2-T1) that considers the asymmetry about the mid-sagittal plane has been reported. The aims of this study were to consider asymmetry in a FE model of the full cervical spine and to investigate the influences of ligaments, facet joints, and disk nucleus on the stability of the asymmetric model during flexion and extension. The model was validated against various published in vitro studies and FE studies for the three main loading planes. Next, the C4-C5 level was modified to simulate different cases to investigate the role of the soft tissues in segmental stability. The FE model predicted that excluding the interspinous ligament (ISL) from the index level would cause excessive instability during flexion and that excluding the posterior longitudinal ligament (PLL) or the ligamentum flavum (LF) would not affect segmental rotation. During extension, motion increased when the facet joints were excluded. The model without disk nucleus was unstable compared to the intact model at lower loads and exhibited a similar rotation response at higher loads. PMID:24641811

  9. Voltage-gated proton channels: what' next?

    PubMed Central

    DeCoursey, Thomas E

    2008-01-01

    This review is an attempt to identify and place in context some of the many questions about voltage-gated proton channels that remain unsolved. As the gene was identified only 2 years ago, the situation is very different than in fields where the gene has been known for decades. For the proton channel, most of the obvious and less obvious structure–function questions are still wide open. Remarkably, the proton channel protein strongly resembles the voltage-sensing domain of many voltage-gated ion channels, and thus offers a novel approach to study gating mechanisms. Another surprise is that the proton channel appears to function as a dimer, with two separate conduction pathways. A number of significant biological questions remain in dispute, unanswered, or in some cases, not yet asked. This latter deficit is ascribable to the intrinsic difficulty in evaluating the importance of one component in a complex system, and in addition, to the lack, until recently, of a means of performing an unambiguous lesion experiment, that is, of selectively eliminating the molecule in question. We still lack a potent, selective pharmacological inhibitor, but the identification of the gene has allowed the development of powerful new tools including proton channel antibodies, siRNA and knockout mice. PMID:18801839

  10. VOSCH: Voltage scaled cache hierarchies

    Microsoft Academic Search

    Weng-fai Wong; Cheng-kok Koh; Yiran Chen; Hai Li

    2007-01-01

    The cache hierarchy of state-of-the-art—especially multicore—microprocessors consumes a significant amount of area and energy. A significant amount of research has been devoted especially to reducing the latter. One of the most important microarchitectural techniques proposed for the energy management is dynamic voltage scaling (DVS). In DVS solutions, each cache operates at a number of differ- ent voltages. Most of the

  11. Ultra Low Voltage SRAM Design

    Microsoft Academic Search

    Naveen Verma; Anantha P. Chandrakasan

    \\u000a Aggressive scaling of the supply voltage to SRAMs greatly minimizes their active and leakage power, a dominating portion of\\u000a the total power in an increasing number of applications. Hence, highly energy-constrained systems, where performance requirements\\u000a are secondary, benefit greatly from SRAMs that provide read and write functionality at the lowest possible voltage, particularly\\u000a down to 0.3 V. However, conventional bit-cells and

  12. Introduction to Voltage and Current

    NSDL National Science Digital Library

    This document from CREATE California provides a basic introduction to voltage and current. The material would work well as a review for students who had already had some classroom instruction on the topic, or as an extra reading assignment. The text covers atomic structure, electrical charge, voltage, current, conservation of energy and forms of energy. The material is available for download in PDF file format.

  13. RICH High Voltages & PDF Analysis @ LHCb

    E-print Network

    Fanchini, E

    2009-01-01

    In the LHCb experiment an important issue is the identification of the hadrons of the final states of the B mesons decays. Two RICH subdetectors are devoted to this task, and the Hybrid Photon Detectors (HPDs) are the photodetectors used to detect Cherenkov light. In this poster there is a description of how the very high voltage (-18 KV) supply stability used to power the HPDs is monitored. It is also presented the basics of a study which can be done with the first collision data: the analysis of the dimuons from the Drell-Yan process. This process is well known and the acceptance of the LHCb detector in terms of pseudorapidity will be very useful to improve the knowledge of the proton structure functions or, alternatively, try to estimate the luminosity from it.

  14. Understanding Pound-Drever-Hall locking using voltage controlled radio-frequency oscillators: An undergraduate experiment

    Microsoft Academic Search

    C. E. Liekhus-Schmaltz; J. D. D. Martin

    2011-01-01

    We have developed a senior undergraduate experiment that illustrates frequency stabilization techniques using radio-frequency electronics. The primary objective is to frequency stabilize a voltage controlled oscillator to a cavity resonance at 800 MHz using the Pound-Drever-Hall method. This technique is commonly applied to stabilize lasers at optical frequencies. By using only radio-frequency equipment it is possible to systematically study aspects

  15. Lactobionic acid as antioxidant and moisturizing active in alkyl polyglucoside-based topical emulsions: the colloidal structure, stability and efficacy evaluation.

    PubMed

    Tasic-Kostov, M; Pavlovic, D; Lukic, M; Jaksic, I; Arsic, I; Savic, S

    2012-10-01

    Cosmeceutical antioxidants may protect the skin against oxidative injury, involved in the pathogenesis of many skin disorders. However, an unsuitable topical delivery system with compromising safety profile can affect the efficacy of an antioxidant active. This study investigated the antioxidant potential of lactobionic acid (LA), a newer cosmeceutical active, per se (in solution) and incorporated into natural alkyl polyglucoside (APG) emulsifier-based system using 1,1-diphenyl-2-picrylhydrazyl free radical scavenging and lipid peroxidation inhibition assays. The ?-tocopherol was used as a reference compound. The physical stability (using rheology, polarization microscopy, pH and conductivity measurements) of an Alkyl glucoside-based emulsion was evaluated with and without the active (LA); colloidal structure was assessed using polarization and transmission electron microscopy, rheology, thermal and texture analysis. Additionally, the safety profile and moisturizing potential were investigated using the methods of skin bioengineering. Good physical stability and applicative characteristics were obtained although LA strongly influenced the colloidal structure of the vehicle. LA per se and in APG-based emulsion showed satisfying antioxidant activity that promotes it as mild multifunctional cosmeceutical efficient in the treatment and prevention of the photoaged skin. Employed assays were shown as suitable for the antioxidant activity evaluation of LA in APG-based emulsions, but not for ?-tocopherol in the same vehicle. PMID:22691034

  16. A direct DC-link boost voltage PID-like fuzzy control strategy in Z-source inverter

    Microsoft Academic Search

    Xinping Ding; Zhaoming Qian; Shuitao Yang; Bin Cui; Fangzheng Peng

    2008-01-01

    This paper presents a direct peak dc-link boost voltage PID-like fuzzy controller in Z-source inverter. With this technique a constant peak dc-link voltage can be achieved with an excellent transient performance which enhances the rejection of disturbance, including the input voltage and load current variation, and solves the problem of the local dynamic output feedback stabilization of the serious non-minimum

  17. A Method of Sensing Line Voltages for Parameter Adaptation of Inverter-Fed Induction Motor Servo Drives

    Microsoft Academic Search

    R. Krishnan; Frank C. Doran

    1987-01-01

    Most high-performance inverter-fed induction motor drive systems require signals corresponding to the input voltages of the motor for parameter adaptation. Low-performance systems require the signals for stabilization. The voltage signals are used in the controller circuit and therefore require isolation. Isolation of the voltage signals is not a cost-effective solution in low-power motor drive systems. The fact that the base

  18. Voltage-Regulation Performance of a Shunt Active Filter Intended for Installation on a Power Distribution System

    Microsoft Academic Search

    Hideaki Fujita; Hirofumi Akagi

    2007-01-01

    This paper discusses a shunt active filter intended for installation on a power distribution system. The active filter has an additional capability to regulate the distribution-line voltage by means of adjusting reactive power. Theoretical analysis investigates the dynamic performance of combined harmonic damping and voltage regulation. As a result, harmonic damping makes it possible to improve the stability of the

  19. Economic operation of wind farm integrated system considering voltage stability

    Microsoft Academic Search

    Qian Ai; Chenghong Gu

    2009-01-01

    Wind farms interconnected to power system bring new challenges to power system economic operation. It is imperative to study how to solve optimal power flow (OPF) formulation with wind farms. In this paper, a multi-period optimal power flow (DOPF) is studied based on traditional OPF algorithm. According to the characteristic equations of asynchronous generator, the paper deduces a new algorithm

  20. Physical modeling of river spanning rock structures: Evaluating interstitial flow, local hydraulics, downstream scour development, and structure stability

    USGS Publications Warehouse

    Collins, K.L.; Thornton, C.I.; Mefford, B.; Holmquist-Johnson, C. L.

    2009-01-01

    Rock weir and ramp structures uniquely serve a necessary role in river management: to meet water deliveries in an ecologically sound manner. Uses include functioning as low head diversion dams, permitting fish passage, creating habitat diversity, and stabilizing stream banks and profiles. Existing information on design and performance of in-stream rock structures does not provide the guidance necessary to implement repeatable and sustainable construction and retrofit techniques. As widespread use of rock structures increases, the need for reliable design methods with a broad range of applicability at individual sites grows as well. Rigorous laboratory testing programs were implemented at the U.S. Bureau of Reclamation (Reclamation) and at Colorado State University (CSU) as part of a multifaceted research project focused on expanding the current knowledge base and developing design methods to improve the success rate of river spanning rock structures in meeting project goals. Physical modeling at Reclamation is being used to measure, predict, and reduce interstitial flow through rock ramps. CSU is using physical testing to quantify and predict scour development downstream of rock weirs and its impact on the stability of rock structures. ?? 2009 ASCE.

  1. Using Mechanistic Understanding of Streambank Processes and a Deterministic Bank-Stability Model to Design and Evaluate a Reach-Scale Restoration Project

    NASA Astrophysics Data System (ADS)

    Simon, Andrew; Derrick, David; Bankhead, Natasha

    2010-05-01

    Sediment is one of the leading contributors to water-quality impairment in the United States and streambank erosion has been found to be the dominant source of sediment in many disturbed watersheds. Goodwin Creek is a typical incised channel in northeastern Mississippi, USA (4.7 m-deep) that yields about an order of magnitude more suspended sediment than stable, "reference" streams in the region. Periodic channel surveys with dating of woody vegetation in an actively eroding meander disclosed a migration rate of 0.5 m/y. Because of continued land loss by mass failure of the streambanks, a restoration project was designed to stabilize the banks. Bank retreat occurs by interactions between hydraulic forces acting at the bed and bank toe and gravitational forces acting on in situ bank material. In fact, bank-toe protection which inhibits steepening of the bank, has been found to be one of the most effective means of stabilizing the upper part of the bank. To provide a stable alternative, analysis of the restored configuration needed to mechanistically address both hydraulic erosion and geotechnical stability. This was accomplished using the Bank-Stability and Toe-Erosion Model (BSTEM). The proposed design was limited to 1:1 bank slopes due to the proximity of a road and included longitudinal stone-toe protection and bendway weirs to counter basal erosion by hydraulic shear. Worst-case conditions under the proposed design were simulated by modeling (1) typical, annual high flows (3 m-deep) to evaluate the amount of bank-toe erosion that would occur, and (2) geotechnical stability where groundwater levels were high and flow had receded to low-flow conditions in the channel (drawdown case). Stone size was selected based on a 1-D hydraulic analysis such that the stone would not be mobilized at peak flows where average boundary shear stresses can reach 60 - 80 N/m2. Calculations were made for a 3 m-deep flow at slopes between 0.002 and 0.003, resulting in recommended stone sizes of 42 and 63 cm, respectively. Simulation of existing bank-stability conditions supported observations over the past 10 years where under low-flow conditions and a relatively deep near-bank groundwater table, banks were stable, but become unstable with higher levels of saturation. Keeping the geotechnical properties of the banks constant, the simulations were repeated with the designed 1:1 geometry. Much like the results for the existing geometry, the designed slope would be stable at low-flow conditions, but unstable for the drawdown case. In an attempt to increase the stability under drawdown conditions, simulations were conducted to include root reinforcement provided by common riparian species. This was attempted initially using Salix nigra because this is one of the most commonly used woody-riparian species in restoration work. Results, however, still showerd that the bank would be unstable. Simulations were repeated with Platanus occidentalis, which has been shown along with Betula nigra to provide the greatest amount of root reinforcement. In this case, stability was simulated. The design was, therefore, implemented and constructed in a week. Over the period March 2007 to January 2010, there was no hydraulic erosion at the bank toe and no mass failures of the upper part of the bank. The most significant change in the channel was up to 0.5m of scour along some parts of the streambed. This was expected because of (1) the re-direction of flows into the center of the channel, and (2) the temporary fining of the streambed in some places due to construction activities (from 80% to 13% gravel). Post-construction storm events flushed much of the sand-sized material out of the cross section and by November 2007 the streambed was again composed of about 80% gravel.

  2. Real-Time Security Assessment of Angle Stability Using Synchrophasors

    E-print Network

    Real-Time Security Assessment of Angle Stability Using Synchrophasors Final Project Report Power 1996 PSERC #12;Real-Time Security Assessment of Angle Stability and Voltage Stability Using Engineering Research Center (PSERC) re- search project S-31, titled "Real-Time Security Assessment of Angle

  3. Application of microchip electrophoresis sodium dodecyl sulfate for the evaluation of change of degradation species of therapeutic antibodies in stability testing.

    PubMed

    Yagi, Yuki; Kakehi, Kazuaki; Hayakawa, Takao; Suzuki, Shigeo

    2014-01-01

    We evaluated the performance of a commercial microchip electrophoresis instrument (LabChip(®) GXII) for the evaluation of change of degradation species of therapeutic antibodies in stability testing. This system requires a sample volume of only 5 ?g, and indicates fine resolution of size variant species such as light chain, heavy chain, non-glycosylated heavy chain and various degradation species. Precision and accuracy were high; the intermediate precision of 18 determinations was only 2.1% or less as RSD and recoveries ranged from 97.8 to 103.0% for major species as heavy chain, light chain and intact molecule of a therapeutic antibody. The applicability of this method was demonstrated by applying the method for the analysis of heat-degraded products of three pharmaceutical antibodies. Though some fragment peaks commonly appeared and increased according to temperature regardless of the source of preparations, one of them indicated specific peaks implying the cleavage of the peptide chain of the heavy chain. We also compared the performance of the method with those using conventional capillary-based SDS electrophoresis. Although the absolute purity values expressed as peak area % were different for the two methods, probably due to the difference in the detection methods, similar quality profiles were obtained within 40 s by microchip-based SDS electrophoresis. In addition, the degradation manner of three marketed antibodies depending on temperature was almost the same for the two methods. At the first stage in the development of manufacturing antibody pharmaceuticals, various factors including cell selection, cell cultivation, and formulation development should be evaluated using limited sample amounts. The stability testing using microchip-based electrophoresis seems suitable for these purposes. PMID:24717658

  4. Voltage-Gated Hydrophobic Nanopores

    SciTech Connect

    Lavrik, Nickolay V [ORNL

    2011-01-01

    Hydrophobicity is a fundamental property that is responsible for numerous physical and biophysical aspects of molecular interactions in water. Peculiar behavior is expected for water in the vicinity of hydrophobic structures, such as nanopores. Indeed, hydrophobic nanopores can be found in two distinct states, dry and wet, even though the latter is thermodynamically unstable. Transitions between these two states are kinetically hindered in long pores but can be much faster in shorter pores. As it is demonstrated for the first time in this paper, these transitions can be induced by applying a voltage across a membrane with a single hydrophobic nanopore. Such voltage-induced gating in single nanopores can be realized in a reversible manner through electrowetting of inner walls of the nanopores. The resulting I-V curves of such artificial hydrophobic nanopores mimic biological voltage-gated channels.

  5. High-voltage coaxial switch

    SciTech Connect

    Rink, J.P.

    1981-06-03

    A coaxial high voltage, high current switch having a solid cylindrical cold cathode coaxially surrounded by a thin hollow cylindrical inner electrode and a larger hollow cylindrical outer electrode is described. A high voltage trigger between the cathode and the inner electrode causes electrons to be emitted from the cathode and flow to the inner electrode preferably through a vacuum. Some of the electrons penetrate the inner electrode and cause a volumetric discharge in the gas (which may be merely air) between the inner and outer electrodes. The discharge provides a low impedance path between a high voltage charge placed on the outer electrode and a load (which may be a high power laser) coupled to the inner electrode. For high repetition rate the gas between the inner and outer electrodes may be continuously exchanged or refreshed under pressure.

  6. Safe epoxy encapsulant for high voltage magnetics

    SciTech Connect

    Sanchez, R.O.; Archer, W.E.

    1998-01-01

    This paper describes the use of Formula 456, an aliphatic amine cured epoxy for impregnating coils and high voltage transformers. Sandia has evaluated a number of MDA-free epoxy encapsulants which relied on either anhydride or other aromatic amine curing agents. The use of aliphatic amine curing agents was more recently evaluated and has resulted in the definition of Formula 456 resin. Methylene dianiline (MDA) has been used for more than 20 years as the curing agent for various epoxy formulations throughout the Department of Energy and much of industry. Sandia National Laboratories began the process of replacing MDA with other formulations because of regulations imposed by OSHA on the use of MDA. OSHA has regulated MDA because it is a suspect carcinogen. Typically the elimination of OSHA-regulated materials provides a rare opportunity to qualify new formulations in a range of demanding applications. It was important to take full advantage of that opportunity, although the associated materials qualification effort was costly. Small high voltage transformers are one of those demanding applications. The successful implementation of the new formulation for high reliability transformers will be described. The test results that demonstrate the parts are qualified for use in DOE weapon systems will be presented.

  7. Characteristics of MOS-controlled thyristors under zero voltage soft-switching conditions

    Microsoft Academic Search

    R. W. A. A. De Doncker; T. M. Jahns; A. V. Radun; D. L. Watrous; V. A. K. Temple

    1992-01-01

    During the development of new MOS-controlled thyristors (MCTs), considerable effort has been spent to evaluate and enhance the dynamic performance of MCTs under zero-voltage soft-switching conditions encountered in several resonant converter configurations. The authors summarize key MCT characterization results as they relate to their dynamic performance during zero-voltage switching. Furthermore, a test circuit that enables characterization of the zero-voltage turn-on

  8. An optical AC voltage sensor based on the transverse Pockels effect.

    PubMed

    Pan, Feng; Xiao, Xia; Xu, Yan; Ren, Shiyan

    2011-01-01

    This paper introduces an optical AC voltage sensor based on the transverse Pockels effect. The sensor utilizes a bulk Bi(4)Ge(3)O(12) (BGO) crystal as the sensing element. The measurement principle has been described and prototype of the sensor has been constructed and evaluated. Good linearity and accuracy performance was obtained for AC voltage measurement. The proposed sensor can be thus applied to high AC voltage measurements in the electric power industry. PMID:22163974

  9. Ancillary service details: Voltage control

    SciTech Connect

    Kirby, B.; Hirst, E.

    1997-12-01

    Voltage control is accomplished by managing reactive power on an alternating-current power system. Reactive power can be produced and absorbed by both generation and transmission equipment. Reactive-power devices differ substantially in the magnitude and speed of response and in their capital costs. System operators, transmission owners, generators, customers, power marketers, and government regulators need to pay close attention to voltage control as they restructure the U.S. electricity industry. Voltage control can affect reliability and commerce in three ways: (1) Voltages must be maintained within an acceptable range for both customer and power-system equipment to function properly. (2) The movement of reactive power consumes transmission resources, which limits the ability to move real power and worsens congestion. (3) The movement of reactive power results in real-power losses. When generators are required to supply excessive amounts of reactive power, their real-power production must be curtailed. These opportunity costs are not currently compensated for in most regions. Current tariffs are based on embedded costs. These embedded-cost tariffs average about $0.51/MWh, equivalent to $1.5 billion annually for the United States as a whole. Although this cost is low when compared with the cost of energy, it still aggregates to a significant amount of money. This report takes a basic look at why the power system requires reactive power (an appendix explains the fundamentals of real and reactive power). The report then examines the various types of generation and transmission resources used to supply reactive power and to control voltage. Finally it discusses how these resources are deployed and paid for in several reliability regions around the country. As the U.S. electricity industry is restructured, the generation, transmission, and system-control equipment and functions that maintain voltages within the appropriate ranges are being deintegrated.

  10. Evaluation of Data Stability and Analysis of Degradation Factors of Digital Versatile Disk Recordable (DVD+R) for Archival Application

    NASA Astrophysics Data System (ADS)

    Lee, Kwan-Yong; Lim, Dong-Soo; Kim, Ki-Hyun; Cho, Won-Ik; Kim, Young-Joo

    2012-08-01

    Optical disks are widely used in libraries and archives as digital data media due to their archival storage stability. Nevertheless, there is relatively less focus on the understanding of physical and chemical degradation mechanism. To observe the degradation mechanism of an optical disk, the accelerated aging test was designed with high temperature and relative humidity of 85 °C and 85% in this study. After 1500 h of aging, digital versatile disk recordable (DVD+R) media resulted in a high value of over 280 in the PI sum 8 value, which means a severe data degradation in the media. From the microstructural observation of recorded marks and the chemical analysis of the reflective layer after this accelerated aging test, gradual physical deformation of recorded mark edges and chemical change of the reflective layer were observed, and they might be related to the severe increase of PI sum 8.

  11. Development of a Combined Solution Formulation of Atropine Sulfate and Obidoxime Chloride for Autoinjector and Evaluation of Its Stability

    PubMed Central

    Ettehadi, Hossein Ali; Ghalandari, Rouhollah; Shafaati, Alireza; Foroutan, Seyed Mohsen

    2013-01-01

    Atropine (AT) and oximes, alone or in combination, have been proven greatly valuable therapeutics in the treatment of organophosphates intoxications. An injectable mixture of AT and obidoxime (OB) was formulated for the administration by automatic self-injector. The aqueous single dose solution contained 275 mg obidoxime chloride and 2.5 mg atropine sulfate per 1 mL (220 mg and 2 mg per 0.8 effective dose, respectively). The final solution was sterilized by filtration through a 0.22 ?m pore size filter. This more concentrated solution allowed to use a smaller size and lighter weight cartridge. Quality control tests, including assay of the two major compounds were performed separately, using reversed-phase HPLC methods. Besides, the stability test was carried out according to ICH guideline for the accelerated test. The obtained results showed that the proposed formulation is stable over a period of 2 years after preparation. PMID:24250669

  12. Development of a combined solution formulation of atropine sulfate and obidoxime chloride for autoinjector and evaluation of its stability.

    PubMed

    Ettehadi, Hossein Ali; Ghalandari, Rouhollah; Shafaati, Alireza; Foroutan, Seyed Mohsen

    2013-01-01

    Atropine (AT) and oximes, alone or in combination, have been proven greatly valuable therapeutics in the treatment of organophosphates intoxications. An injectable mixture of AT and obidoxime (OB) was formulated for the administration by automatic self-injector. The aqueous single dose solution contained 275 mg obidoxime chloride and 2.5 mg atropine sulfate per 1 mL (220 mg and 2 mg per 0.8 effective dose, respectively). The final solution was sterilized by filtration through a 0.22 ?m pore size filter. This more concentrated solution allowed to use a smaller size and lighter weight cartridge. Quality control tests, including assay of the two major compounds were performed separately, using reversed-phase HPLC methods. Besides, the stability test was carried out according to ICH guideline for the accelerated test. The obtained results showed that the proposed formulation is stable over a period of 2 years after preparation. PMID:24250669

  13. Monitoring and evaluating the stability of soil slopes: A review on various available methods and feasibility of acoustic emission technique

    NASA Astrophysics Data System (ADS)

    Zaki, Ahmad; Chai, Hwa Kian; Razak, Hashim Abdul; Shiotani, Tomoki

    2014-09-01

    Landslide is considered as one of the major natural hazards that cause enormous social and economic losses. Some techniques have been introduced to monitor the stability of slopes, such as the global positioning system (GPS), the geographic information system (GIS), aerial photography, and inclinometers. Each one of these offers advantages against others, but at the same time also possesses different limitations. Acoustic emission (AE) has recently been recognized as one of the feasible techniques to monitor soil slope. This article addresses issues involved in application of AE techniques for soil slope monitoring. If it is properly instrumented, AE could provide effective solutions for detecting early activities related to landslide development and giving early warning to such failures.

  14. A Novel Voltage Transients Base Protection Criterion for T-Type High Voltage Transmission Lines

    Microsoft Academic Search

    Xia Mingchao; Lin Yong

    2007-01-01

    Based on the wavelet transform results of the voltage transients from the three ends of the line, a novel protection criterion for T-type high voltage power transmission line is presented. The attenuation effects of high voltage transmission line and busbar capacitance to high-frequency current signals is analyzed. The Transient Voltage Content Ratio (TVCR) and Transient Voltage Singularity Ratio (TVSR) are

  15. Slope-Permissive UnderVoltage Load Shed Relay for Delayed Voltage Recovery Mitigation

    Microsoft Academic Search

    S. Mark Halpin; Keith A. Harley; Robert A. Jones; Lee Y. Taylor

    2008-01-01

    In this paper, a new relay algorithm is proposed for under-voltage load shedding (UVLS) based on rate of voltage recovery and predicted time to recover above a preset voltage threshold. Simulation experience in the Southern Electric System has shown that conventional UVLS relay logic is ill-suited to the task of mitigating delayed voltage recovery and fast voltage collapse situations while

  16. Evaluation of the pH- and Thermal Stability of the Recombinant Green Fluorescent Protein (GFP) in the Presence of Sodium Chloride

    NASA Astrophysics Data System (ADS)

    Ishii, Marina; Kunimura, Juliana Sayuri; Jeng, Hélio Tallon; Vessoni Penna, Thereza Christina; Cholewa, Olivia

    The thermal stability of recombinant green fluorescent protein (GFP) in sodium chloride (NaCl) solutions at different concentrations, pH, and temperatures was evaluated by assaying the loss of fluorescence intensity as a measure of denaturation. GFP, extracted from Escherichia coli cells by the three-phase partitioning method and purified through a butyl hydrophobic interaction chromatography (HIC) column, was diluted in water for injection (WFI) (pH 6.0-7.0) and in 10 mM buffer solutions (acetate, pH 5.0; phosphate, pH 7.0; and Tris-EDTA, pH 8.0) with 0.9-30% NaCl or without and incubated at 80-95°C. The extent of protein denaturation was expressed as a percentage of the calculated decimal reduction time (D-value). In acetate buffer (pH 4.84 ±0.12), the mean D-values for 90% reduction in GFP fluorescence ranged from 2.3 to 3.6 min, independent of NaCl concentration and temperature. GFP thermal stability diluted in WFI (pH 5.94±0.60) was half that observed in phosphate buffer (pH 6.08±0.60); but in both systems, D-values decreased linearly with increasing NaCl concentration, with D-values (at 80°C) ranging from 3.44, min (WFI) to 6.1 min (phosphate buffer), both with 30% NaCl. However, D-values in Tris-EDTA (pH 7.65±0.17) were directly dependent on the NaCl concentration and 5-10 times higher than D-values for GFP in WFI at 80°C. GFP pH-and thermal stability can be easily monitored by the convenient measure of fluorescence intensity and potentially be used as an indicator to monitor that processing times and temperatures were attained.

  17. Evaluation of Extracted Organic Carbon and Microbial Biomass as Stability Parameters in Ligno-Cellulosic Waste Composts

    Microsoft Academic Search

    Claudio Mondini; Miguel A. Sánchez-Monedero; Tania Sinicco; Liviana Leita

    2006-01-01

    Extracted organic C and microbial biomass were evaluated as sta- bility parameters in 3 different ligno-cellulosic waste composts. Or- ganic C was extracted by both water and alkali and further separated in humic-like carbon (HLC) and nonhumic carbon (NHC). Conven- tional humification parameters, such as humification index and de- gree of humification were calculated from NHC and HLC. Microbial biomass

  18. Effects of Pt\\/C, Pd\\/C and PdPt\\/C anode catalysts on the performance and stability of air breathing direct formic acid fuel cells

    Microsoft Academic Search

    Ping Hong; Fan Luo; Shijun Liao; Jianhuang Zeng

    2011-01-01

    Pt\\/C, Pd\\/C and PdPt\\/C catalysts are potential anodic candidates for electro-oxidation of formic acid. In this work we designed a miniature air breathing direct formic acid fuel cell, in which gold plated printed circuit boards are used as end plates and current collectors, and evaluated the effects of anode catalysts on open circuit voltage, power density and long-term discharging stability

  19. Tc-99m PYP scanning following low voltage electrical injury.

    PubMed

    Spencer, R R; Williams, A G; Mettler, F A; Christie, J H; Rosenberg, R D; Weaver, W D

    1983-12-01

    An adolescent boy sustained low voltage electrical injury to his extremities when he inadvertently touched a low tension (440 volts) wire with a metal tube. Early in his hospital course, he was evaluated with Tc-99m pyrophosphate whole body scanning for the extent of his injuries. The scintigraphic findings correlated well with his subsequent clinical course. PMID:6317262

  20. Accurate voltage phasor measurement in a series-compensated network

    Microsoft Academic Search

    J. Lambert; D. McNabb; A. G. Phadke

    1994-01-01

    This paper describes the feasibility studies concerning an accurate voltage phasor measurement in series-compensated network undergoing large disturbances. The principal modes of distortions in such a network are described. Some of these modes are changing with the fundamental frequency. The phasor evaluation is based on a new digital filter approach in which the fundamental frequency is estimated using a least-square

  1. Bioequivalence studies and sugar-based excipients effects on the properties of new generic ketoconazole tablets formulations and stability evaluation by using direct compression method.

    PubMed

    Viçosa, Alessandra L; Chatah, Eliane N; Santos, Tereza C; Jones, Luiz F; Dantas, Cide B; Dornelas, Camila B; Rodrigues, Carlos R; Castro, Helena C; Sousa, Valéria P; Dias, Luiza R S; Cabral, Lúcio M

    2009-01-01

    In this work we described the development of a new solid oral formulation of ketoconazole, a broad-spectrum antifungal agent that belongs to the class II of Biopharmaceutics Classification System (BCS). The ketoconazole raw material supplier was selected to present a best flow and compactation. In addition we used direct compression and superdisintegrants associated to polyols to enhance the dissolution of the ketoconazole tablets. The dissolution was evaluated based in level C in vivo/in vitro correlation established. The best formulation was obtained with croscarmellose/maltose association that in the accelerated stability assays presented no differences on quality specifications and no drug-excipients interaction by DSC analyses. In this work it was possible to confirm the use of sugar-based excipients as suitable dissolution enhancers in pharmaceutical technology and real processes conditions. PMID:19552561

  2. Comparison of the Structural Irregularity and Damage Evaluation Routine (SIDER) Inspection Method with Ultrasonic and Thermographic Inspections to Locate Impact Damage on an A320 Vertical Stabilizer

    NASA Astrophysics Data System (ADS)

    Crane, R. M.; Ratcliffe, C. P.; Gould, R.; Johnston, A.; Forsyth, D. S.

    2007-03-01

    The U.S. Navy is currently involved in the development of several large area composite structures for fleet implementation. Techniques to provide rapid nondestructive inspection of large area composite structural components are required for these applications. An inspection technique, structural irregularity and damage evaluation routine (SIDER), has been developed by the Navy to rapidly locate areas of stiffness variation that results from processing anomalies and in-service damage. SIDER was used to locate impact damage created on an A320 vertical stabilizer. Various impact energy levels were used, from 50 J, simulating barely visible impact damage, to 120 J, simulating significant impact damage. The SIDER results were compared with conventional ultrasonic and thermographic inspections.

  3. Time's Ontic Voltage Craig Callender

    E-print Network

    Callender, Craig

    Time's Ontic Voltage Craig Callender Philosophy of time, as practiced throughout the last hundred venue for attacking questions about the nature of time--in sharp contrast to the primary venue slowly in philosophy of time.1 Since twentieth-century analytic philosophy as a whole often drew

  4. High voltage MOSFET switching circuit

    DOEpatents

    McEwan, T.E.

    1994-07-26

    The problem of source lead inductance in a MOSFET switching circuit is compensated for by adding an inductor to the gate circuit. The gate circuit inductor produces an inductive spike which counters the source lead inductive drop to produce a rectangular drive voltage waveform at the internal gate-source terminals of the MOSFET. 2 figs.

  5. High voltage MOSFET switching circuit

    DOEpatents

    McEwan, Thomas E. (Livermore, CA)

    1994-01-01

    The problem of source lead inductance in a MOSFET switching circuit is compensated for by adding an inductor to the gate circuit. The gate circuit inductor produces an inductive spike which counters the source lead inductive drop to produce a rectangular drive voltage waveform at the internal gate-source terminals of the MOSFET.

  6. Nonlinear electrokinetics at large voltages

    NASA Astrophysics Data System (ADS)

    Bazant, Martin Z.; Sabri Kilic, Mustafa; Storey, Brian D.; Ajdari, Armand

    2009-07-01

    The classical theory of electrokinetic phenomena assumes a dilute solution of point-like ions in chemical equilibrium with a surface whose double-layer voltage is of order the thermal voltage, kBT/e=25 mV. In nonlinear 'induced-charge' electrokinetic phenomena, such as ac electro-osmosis, several volts ?100kBT/e are applied to the double layer, and the theory breaks down and cannot explain many observed features. We argue that, under such a large voltage, counterions 'condense' near the surface, even for dilute bulk solutions. Based on simple models, we predict that the double-layer capacitance decreases and the electro-osmotic mobility saturates at large voltages, due to steric repulsion and increased viscosity of the condensed layer, respectively. The former suffices to explain observed high-frequency flow reversal in ac electro-osmosis; the latter leads to a salt concentration dependence of induced-charge flows comparable to experiments, although a complete theory is still lacking.

  7. ABBGroup-1-High voltage lab

    E-print Network

    Basse, Nils Plesner

    phase Top right figure: Current (blue) and arc voltage (red). The current is terminated by the vacuum to interrupt the current... Fault arc at a disconnector Fault arc in a substation #12;©ABBGroup-5- 3-Sep-07 3. Arc forms between the separated contacts 4. Arc is extinguished at a current zero (CZ) crossing

  8. Outdoor high voltage polymeric insulators

    Microsoft Academic Search

    R. Hackam

    1998-01-01

    Composite polymeric insulators are increasingly being accepted by the traditionally cautious electric utilities worldwide. They currently represent about 70% of installed new high voltage insulators in North America. The tremendous growth in the applications of non-ceramic insulators is due to their advantages over the traditional ceramic and glass insulators. However, because polymeric insulators are relatively new the expected lifetime is

  9. High-Voltage Droplet Dispenser

    NASA Technical Reports Server (NTRS)

    Eichenberg, Dennis J.

    2003-01-01

    An apparatus that is extremely effective in dispensing a wide range of droplets has been developed. This droplet dispenser is unique in that it utilizes a droplet bias voltage, as well as an ionization pulse, to release a droplet. Apparatuses that deploy individual droplets have been used in many applications, including, notably, study of combustion of liquid fuels. Experiments on isolated droplets are useful in that they enable the study of droplet phenomena under well-controlled and simplified conditions. In this apparatus, a syringe dispenses a known value of liquid, which emerges from, and hangs onto, the outer end of a flat-tipped, stainless steel needle. Somewhat below the needle tip and droplet is a ring electrode. A bias high voltage, followed by a high-voltage pulse, is applied so as to attract the droplet sufficiently to pull it off the needle. The voltages are such that the droplet and needle are negatively charged and the ring electrode is positively charged.

  10. Voltage Controlled Current Source (VCCS)

    NSDL National Science Digital Library

    Dorf, Richard C.

    Hosted by Clarkson University, this websited contains an applet which demonstrates a circuit that contains a voltage controlled current source (VCCS). The gain of the VCCS can be changed using the scrollbar. This simple resource is a nice representation for a technical education classroom.

  11. Stability and Feedback Stabilization 1639 Stability and Feedback Stabilization

    E-print Network

    Sontag, Eduardo

    Stability and Feedback Stabilization 1639 Stability and Feedback Stabilization EDUARDO D. SONTAG of the Subject Introduction Linear Systems Nonlinear Systems: Continuous Feedback Discontinuous Feedback) if it is possible to find a feedback law that renders that state a globally asymptotically stable equi- librium

  12. Establishing a High-content Analysis Method for Tubulin Polymerization to Evaluate Both the Stabilizing and Destabilizing Activities of Compounds.

    PubMed

    Sum, Chi Shing; Nickischer, Debra; Lei, Ming; Weston, Andrea; Zhang, Litao; Schweizer, Liang

    2014-01-01

    Microtubules are important components of the cellular cytoskeleton that play roles in various cellular processes such as vesicular transport and spindle formation during mitosis. They are formed by an ordered organization of ?-tubulin and ?-tubulin hetero-polymers. Altering microtubule polymerization has been known to be the mechanism of action for a number of therapeutically important drugs including taxanes and epothilones. Traditional cell-based assays for tubulin-interacting compounds rely on their indirect effects on cell cycle and/or cell proliferation. Direct monitoring of compound effects on microtubules is required to dissect detailed mechanisms of action in a cellular setting. Here we report a high-content assay platform to monitor tubulin polymerization status by directly measuring the acute effects of drug candidates on the cellular tubulin network with the capability to dissect the mechanisms of action. This high-content analysis distinguishes in a quantitative manner between compounds that act as tubulin stabilizers versus those that are tubulin destabilizers. In addition, using a multiplex approach, we expanded this analysis to simultaneously monitor physiological cellular responses and associated cellular phenotypes. PMID:24596681

  13. Establishing a High-content Analysis Method for Tubulin Polymerization to Evaluate Both the Stabilizing and Destabilizing Activities of Compounds

    PubMed Central

    Sum, Chi Shing; Nickischer, Debra; Lei, Ming; Weston, Andrea; Zhang, Litao; Schweizer, Liang

    2014-01-01

    Microtubules are important components of the cellular cytoskeleton that play roles in various cellular processes such as vesicular transport and spindle formation during mitosis. They are formed by an ordered organization of ?-tubulin and ?-tubulin hetero-polymers. Altering microtubule polymerization has been known to be the mechanism of action for a number of therapeutically important drugs including taxanes and epothilones. Traditional cell-based assays for tubulin-interacting compounds rely on their indirect effects on cell cycle and/or cell proliferation. Direct monitoring of compound effects on microtubules is required to dissect detailed mechanisms of action in a cellular setting. Here we report a high-content assay platform to monitor tubulin polymerization status by directly measuring the acute effects of drug candidates on the cellular tubulin network with the capability to dissect the mechanisms of action. This high-content analysis distinguishes in a quantitative manner between compounds that act as tubulin stabilizers versus those that are tubulin destabilizers. In addition, using a multiplex approach, we expanded this analysis to simultaneously monitor physiological cellular responses and associated cellular phenotypes. PMID:24596681

  14. Voltage-gated Proton Channels

    PubMed Central

    DeCoursey, Thomas E.

    2014-01-01

    Voltage-gated proton channels, HV1, have vaulted from the realm of the esoteric into the forefront of a central question facing ion channel biophysicists, namely the mechanism by which voltage-dependent gating occurs. This transformation is the result of several factors. Identification of the gene in 2006 revealed that proton channels are homologues of the voltage-sensing domain of most other voltage-gated ion channels. Unique, or at least eccentric, properties of proton channels include dimeric architecture with dual conduction pathways, perfect proton selectivity, a single-channel conductance ~103 smaller than most ion channels, voltage-dependent gating that is strongly modulated by the pH gradient, ?pH, and potent inhibition by Zn2+ (in many species) but an absence of other potent inhibitors. The recent identification of HV1 in three unicellular marine plankton species has dramatically expanded the phylogenetic family tree. Interest in proton channels in their own right has increased as important physiological roles have been identified in many cells. Proton channels trigger the bioluminescent flash of dinoflagellates, facilitate calcification by coccolithophores, regulate pH-dependent processes in eggs and sperm during fertilization, secrete acid to control the pH of airway fluids, facilitate histamine secretion by basophils, and play a signaling role in facilitating B-cell receptor mediated responses in B lymphocytes. The most elaborate and best-established functions occur in phagocytes, where proton channels optimize the activity of NADPH oxidase, an important producer of reactive oxygen species. Proton efflux mediated by HV1 balances the charge translocated across the membrane by electrons through NADPH oxidase, minimizes changes in cytoplasmic and phagosomal pH, limits osmotic swelling of the phagosome, and provides substrate H+ for the production of H2O2 and HOCl, reactive oxygen species crucial to killing pathogens. PMID:23798303

  15. [Quantitative evaluation of pilot workload influence on functional stability and occupational health of pilots (scientific and practical aspects)].

    PubMed

    Vartbaronov, R A; Khomenko, M N; Bondarenko, R A

    2000-01-01

    Based on early concepts of quantitative evaluation of pilotage overload influence on pilot, the authors justified principles and criteria for biometric characterization of overload parameters and human response concerning the problem of manoeuvreable flight and pilot's occupational health preservation. The article presents quantitative dependencies between various overload parameters, occupational conditions and -effects, considering risk of disorders that determine potential unreliability of pilot in manoeuvreable flight and possible cumulative effects from dose viewpoint. PMID:10881541

  16. Proposal of the new method to evaluate of the tectonic stability for the last 100 ky in Japan

    Microsoft Academic Search

    R. Hataya; K. Tanaka

    2001-01-01

    1. INTRODUCTION To evaluate the long-term safety of underground high-level radioactive waste repository, it is important to predict futureOs tectonic events, particularly tectonic uplift\\/subsidence, faulting, earthquake and volcanic activity. FutureOs activity is generally predicted by extrapolation of past tectonic characteristics. However, it is difficult to construct the 2-dimensional distribution of the past uplift\\/subsidence rate including inland area. In this study,

  17. SU-E-J-24: An Evaluation of the Stability of Image Quality Parameters of Varian On-Board Imaging (OBI) and EPID Imaging Systems

    SciTech Connect

    Stanley, D; Papanikolaou, N; Gutierrez, A [University of Texas HSC SA, San Antonio, TX (United States)

    2014-06-01

    Purpose: Quality assurance of the image quality for image guided localization systems is crucial to ensure accurate visualization and localization of target volumes. In this study, the long term stability of selected image parameters was assessed and evaluated for CBCT mode, planar radiographic kV mode and the radiographic MV EPID mode. Methods: The CATPHAN, QckV-1 and QC-3 phantoms were used to evaluate the image quality parameters. The planar radiographic images were analyzed in PIPSpro™ with spatial resolution (f30, f40, f50) being recorded. For OBI CBCT, High quality head Full-Fan acquisition and Pelvis Half-Fan acquisition modes were evaluated for Uniformity, Noise, Spatial Resolution, HU constancy and geometric distortion. Dose and kVp for the OBI were recorded using the Unfors RaySafe Xi system with the R/F High Detector for planar kV and the CT detector for CBCT. Dose for the MV EPID was recorded using a PTW975 Semiflex Ion Chamber, PTW Unidos electrometer and SolidWater™. Results: For each metric, values were normalized to the mean and the standard deviations were recorded. For the planar radiographic spatial resolution the f30, f40, f50 were 0.015, 0.008, 0.004 and 0.006, 0.009, 0.018 for the kV and MV, respectively. The standard deviation of the dose for kV was 0.010 and 0.005 for the MV. The standard deviations for Full and half fan were averaged together and the following standard deviations for each metric were recorded: 0.075(uniformity), 0.071(noise), 0.006(AP-Geometric Distortion), 0.005(LAT-Geometric Distortion), 0.058(mean slice thickness), 0.098(f30),0.101(f40),0.124(f50), 0.031(Lung/PMP-HU constancy), 0.063(Water/poly-HU constancy), 0.015(Bone/Derlin-HU constancy),0.006(Dose-Center), 0.004(Dose-Periphery). Using these, tolerances can be reported as a warning and action threshold of 1? and 2?. Conclusion: A study was performed to assess the stability of the basic image quality parameters recommended by TG-142 for the Varian OBI and EPID Imaging systems. The two systems show consistent imaging and dosimetric properties over the evaluated time frame.

  18. Investigation of transmission system voltage flicker due to multiple AC and DC furnace operations

    Microsoft Academic Search

    S. R. Mendis; M. T. Bishop; A. V. Do; D. M. Boyd

    1995-01-01

    This paper discusses an investigation of transmission system voltage flicker due to the effects of the operation of multiple AC and DC furnaces, harmonic filters, and static var systems. The utility transmission voltages are measured using a unique flicker measurement and evaluation system. The field tests are compared to an analysis of the expected flicker in the system.

  19. Predicting and preventing problems associated with remote fault-clearing voltage dips

    Microsoft Academic Search

    Larry Conrad; Kevin Little; Cliff Grigg

    1991-01-01

    General techniques for predicting, reducing, and preventing problems associated with remote fault-clearing voltage dips are presented. The basic tools include a computer program to calculate unbalanced fault currents and voltages, reliability data, and fault-clearing device characteristics. Difficult calculations should be performed by any of several good analysis programs that are available. These programs can evaluate alternate configurations to optimize system

  20. Arc voltage for arcing faults on 25(28)kV cables and splices

    Microsoft Academic Search

    B. Koch; P. Christophe

    1993-01-01

    Hazards to people and property due to arcing faults on medium-voltage underground cables and splices are related to the arc power dissipated in the environment by the arc. However, if the fault current may be accurately predicted from known circuit parameters, the arc voltage needed to evaluate the arc's power has no analytical expression due to the fact that the

  1. Coercivity change in an FePt thin layer in a Hall device by voltage application

    NASA Astrophysics Data System (ADS)

    Seki, Takeshi; Kohda, Makoto; Nitta, Junsaku; Takanashi, Koki

    2011-05-01

    The coercivity (Hc) of a perpendicularly magnetized FePt layer was modulated by applying the voltage (Vapp) to a Hall device through MgO and Al-O insulating layers. A change in ˜40 Oe in Hc was observed by changing Vapp from -13 to 13 V. From the quantitative analysis of the voltage effect on Hc, the change in the anisotropy energy by voltage application was evaluated to be 18.6 fJ/V m, which was of the same order as the theoretical prediction. The role of the MgO layer for the voltage effect was also discussed.

  2. Distribution system voltage sags: Interaction with motor and drive loads

    SciTech Connect

    Tang, L.; Lamoree, J.; McGranaghan, M. [Electrotek Concepts, Inc., Knoxville, TN (United States); Mehta, H. [Electric Power Research Institute, Palo Alto, CA (United States)

    1994-12-31

    Several papers have been written on the response of directly connected induction motors or adjustable speed drive (ASD) connected motors to unbalanced and balanced voltage sags caused by faults on the power system. This paper will detail the interaction between the motors and drives and the supplying distribution system both during and after the voltage sag. In addition, the system effect of transferring the loads during the sag to an alternate feed with solid-state switching is evaluated. The Electro-Magnetic Transients Program (EMTP) was used for the analysis.

  3. Preparation, characterization and in vitro evaluation of sterically stabilized liposome containing a naphthalenediimide derivative as anticancer agent.

    PubMed

    Parise, Amelia; Milelli, Andrea; Tumiatti, Vincenzo; Minarini, Anna; Neviani, Paolo; Zuccari, Guendalina

    2013-11-29

    Abstract The aim of this study was to incorporate a new naphthalenediimide derivative (AN169) with a promising anticancer activity into pegylated liposomes to an extent that allows its in vitro and in vivo testing without use of toxic solvent. AN169-loaded liposomes were prepared using the thin-film hydration method and characterized for size, polydispersity index, drug content and drug release. We examined their lyophilization ability in the presence of cryoprotectants (trehalose, sucrose and lysine) and the long-term stability of the lyophilized products stored at 4?°C for 3 and 6 months by particle size changes and drug leakage. AN169 was successfully loaded into liposomes with an entrapment efficiency of 87.3?±?2.5%. The hydrodynamic diameter of these liposomes after sonication was ?145?nm with a high degree of monodispersity. Trehalose was found to be superior to the other lyoprotectants. In particular, trehalose 1:10 lipid:cryoprotectant molar ratio may provide stable lyophilized liposomes with the conservation of physicochemical properties upon freeze-drying and long-term storage conditions. We also assessed their in vitro antitumor activity in human cancer cell lines (HTLA-230 neuroblastoma, Mel 3.0 melanoma, OVCAR-3 ovarian carcinoma and SV620 prostate cancer cells). However, only after 72?h incubation, loaded liposomes showed almost the same IC50 as free AN169. In conclusion, we developed a stable lyophilized liposomal formulation for intravenous administration of AN169 as anticancer drug, with the advantage of avoiding the use of potentially toxic solubilizing agents for future in vivo experiments. PMID:24286206

  4. A Comparative Evaluation of the Dimensional Stability of Three Different Elastomeric Impression Materials after Autoclaving – An Invitro Study

    PubMed Central

    Thota, Kiran Kumar; Ravuri, Rajyalakshmi; Tella, Suchita

    2014-01-01

    Aim of the Study: The purpose of the study was to determine the effect of autoclaving on the dimensional stability of three different elastomeric impression materials at three different time intervals. Materials and Methods: Standardized stainless steel master die as per ADA specification number 19 was fabricated. The impression materials used for the study were condensation silicone (GP1), addition silicone (GP2) and polyether (GP3). A total of 45 samples of the stainless steel die were made (n = 45), that is 15 samples for each group. Impression materials were mixed according to the manufacturer’s instructions and were loaded into the mold to make an impression of the die. Impressions were identified with the help of numerical coding system and measurements were made using stereomicroscope (MAGNUS MSZ-Bi) of 0.65x magnification with the help of image analysis software (IMACE PRO-INSIGHT VERSION.The results were subjected to statistical analysis using one way analysis of variance and student t-test for comparison between the groups. Results: Within the limitations of the study statistically significant dimensional changes were observed for all the three impression materials at three different time intervals but this change was not clinically significant. Conclusion: It is well-known fact that all impressions should be disinfected to avoid possible transmission of infectious diseases either by direct contact or cross contamination. Immersion and spray disinfection as well as various disinfection solutions have been tested and proven to be effective for this purpose. But for elastomeric impression materials these methods have proven to be ineffective as they do not prevent cross contamination among the dental team. So autoclaving was one of the most effective sterilization procedure for condensation silicone and addition silicone. Since polyether is hydrophilic it is better to disinfect the impressions as recommended by the manufacturer or by immersion or spray atomization. PMID:25478447

  5. Impact Analysis of Transient Stability Due to Cyber Attack on FACTS Devices

    E-print Network

    Kundur, Deepa

    Impact Analysis of Transient Stability Due to Cyber Attack on FACTS Devices Bo Chen, Karen L attacks can make the system angle or voltage unstable under the proposed attack scenarios. Index Terms--cyber attack, cyber security, smart grids, SVC, STATCOM, FACTS, transient stability, voltage support device I

  6. Arc voltage measurements of the hyperbaric MIG process

    SciTech Connect

    Huismann, G.; Hoffmeister, H. [Univ. der Bundeswehr, Hamburg (Germany)

    1996-12-01

    As a vital part of the MIG process, the arc controls the stability of the process, the melting of the filler wire and the base material. In order to control and describe the arc behavior, it is necessary to know the voltage- current- arc length relations, or the arc characteristics. Knowledge of arc characteristics is necessary for control of the MIG process and further automation of welding systems, in particular, at hyperbaric welding. In literature, information on arc characteristics for hyperbaric open arc pulsed process is not available so far. Therefore, in the present work, arc characteristics were measured for a pressure range of 1 to 16 bar. In measuring arc voltages and arc lengths of MIG arcs, specific problems are encountered as compared to TIG arcs where the distance between the electrode and work piece can be taken as the arc length and the ohmic voltage drop in the tungsten electrode is low. The movement of the electrode in the MIG process and the deformation of the molten wire end together with weld pool fluctuations are providing a complex system. For determining the arc characteristics certain simplifications are thus required which have been applied in this work. This paper presents a new concept on measuring arc lengths and voltages in the open MIG arc.

  7. Voltage Clamp of Cardiac Muscle in a Double Sucrose Gap

    PubMed Central

    Harrington, Lesley; Johnson, Edward A.

    1973-01-01

    A method of stabilizing the membrane potential of a small area of cardiac muscle membrane and the limitations of this method are described. Tiny bundles or strands, approximately 80 ?m in diameter, of electrically interconnected fibers from the ventricles of rabbit hearts were used in a double sucrose gap. Current records associated with step changes in voltage were complicated by two capacitive surges of current of nodal and nonnodal origin and large “leakage” currents of nonnodal origin resulting mainly from the multifibered nature of the preparation and emphasized by the method. The transient, inward membrane currents in response to moderate depolarizing steps in command potential had the same duration as the upstroke of the action potential. In good runs, currents were smooth and free from notches. These initial currents behaved qualitatively like the initial sodium currents in squid axon and in other excitable membranes. A fraction of the initial sodium current persisted at least as long as 300 ms. The relationship between peak initial current and voltage was graded and linear in the positive direction. In the negative region the relationship was often very steep, indicating insufficient voltage control of all the membranes despite the squareness of the voltage record. Other indications of inadequacy of control could occur and thus even with this optimum preparation of cardiac muscle it was not feasible to analyze quantitatively either the initial or the prolonged sodium currents. PMID:4715582

  8. Low Beam Voltage, 10 MW, L-Band Cluster Klystron

    SciTech Connect

    Teryaev, V.; /Novosibirsk, IYF; Yakovlev, V.P.; /Fermilab; Kazakov, S.; /KEK, Tsukuba; Hirshfield, J.L.; /Yale U. /Omega-P, New Haven

    2009-05-01

    Conceptual design of a multi-beam klystron (MBK) for possible ILC and Project X applications is presented. The chief distinction between this MBK design and existing 10-MW MBK's is the low operating voltage of 60 kV. There are at least four compelling reasons that justify development at this time of a low-voltage MBK, namely (1) no pulse transformer; (2) no oil tank for high-voltage components and for the tube socket; (3) no high-voltage cables; and (4) modulator would be a compact 60-kV IGBT switching circuit. The proposed klystron consists of four clusters containing six beams each. The tube has common input and output cavities for all 24 beams, and individual gain cavities for each cluster. A closely related optional configuration, also for a 10 MW tube, would involve four totally independent cavity clusters with four independent input cavities and four 2.5 MW output ports, all within a common magnetic circuit. This option has appeal because the output waveguides would not require a controlled atmosphere, and because it would be easier to achieve phase and amplitude stability as required in individual SC accelerator cavities.

  9. High stability amplifier

    NASA Technical Reports Server (NTRS)

    Adams, W. A.; Reinhardt, V. S. (inventors)

    1983-01-01

    An electrical RF signal amplifier for providing high temperature stability and RF isolation and comprised of an integrated circuit voltage regulator, a single transistor, and an integrated circuit operational amplifier mounted on a circuit board such that passive circuit elements are located on side of the circuit board while the active circuit elements are located on the other side is described. The active circuit elements are embedded in a common heat sink so that a common temperature reference is provided for changes in ambient temperature. The single transistor and operational amplifier are connected together to form a feedback amplifier powered from the voltage regulator with transistor implementing primarily the desired signal gain while the operational amplifier implements signal isolation. Further RF isolation is provided by the voltage regulator which inhibits cross-talk from other like amplifiers powered from a common power supply. Input and output terminals consisting of coaxial connectors are located on the sides of a housing in which all the circuit components and heat sink are located.

  10. High voltage photovoltaic power converter

    DOEpatents

    Haigh, Ronald E. (Arvada, CO); Wojtczuk, Steve (Cambridge, MA); Jacobson, Gerard F. (Livermore, CA); Hagans, Karla G. (Livermore, CA)

    2001-01-01

    An array of independently connected photovoltaic cells on a semi-insulating substrate contains reflective coatings between the cells to enhance efficiency. A uniform, flat top laser beam profile is illuminated upon the array to produce electrical current having high voltage. An essentially wireless system includes a laser energy source being fed through optic fiber and cast upon the photovoltaic cell array to prevent stray electrical signals prior to use of the current from the array. Direct bandgap, single crystal semiconductor materials, such as GaAs, are commonly used in the array. Useful applications of the system include locations where high voltages are provided to confined spaces such as in explosive detonation, accelerators, photo cathodes and medical appliances.

  11. Voltage-Gated Proton Channels

    PubMed Central

    DeCoursey, Thomas E.

    2013-01-01

    The history of research on voltage-gated proton channels is recounted, from their proposed existence in dinoflagellates by Hastings in 1972 and their demonstration in snail neurons by Thomas and Meech in 1982, to the discovery (after a decade of controversy) of genes that unequivocally code for proton channels in 2006. Voltage-gated proton channels are perfectly selective for protons, conduct deuterons half as well, and the conductance is strongly temperature dependent. These properties are consistent with a conduction mechanism involving hydrogen-bonded-chain transfer, in which the selectivity filter is a titratable amino acid residue. Channel opening is regulated stringently by pH such that only outward current is normally activated. Main functions of proton channels include acid extrusion from cells and charge compensation for the electrogenic activity of the phagocyte NADPH oxidase. Genetic approaches hold the promise of rapid progress in the near future. PMID:18463791

  12. STRUCTURAL BIOLOGY: Voltage Sensor Meets Lipid Membrane

    NSDL National Science Digital Library

    Roderick MacKinnon (Howard Hughes Medical Institute; Rockefeller University; Laboratory of Molecular Neurobiology and Biophysics)

    2004-11-19

    Access to the article is free, however registration and sign-in are required. Several crystal structures of the bacterial voltage-dependent K+ channel have provided intriguing insights into how voltage-dependent ion channels work. In his Perspective, MacKinnon provides a primer on how the voltage sensor of voltage-dependent K+ channels works, and updates the primer with new data provided by the latest spectroscopic study from Perozo's group.

  13. Novel zero-voltage-transition PWM converters

    Microsoft Academic Search

    Guichao Hua; Ching-Shan Leu; Yimin Jiang; Fred C. Y. Lee

    1994-01-01

    To date, soft-switching techniques applied to the PWM converters, with the exception of a few isolated cases, are subjected to either high switch voltage stresses or high switch current stresses, or both. A new class of zero-voltage-transition PWM converters is proposed, where both the transistor and the rectifier operate with zero-voltage switching and are subjected to minimum voltage and current

  14. Nanotechnology for next generation Josephson voltage standards

    Microsoft Academic Search

    Samuel P. Benz; Paul D. Dresselhaus

    2001-01-01

    We have developed two voltage standard systems: 1) the programmable Josephson voltage standard and 2) the Josephson arbitrary waveform synthesizer. The programmable system is fully automated and provides stable programmable dc voltages from -1.2 V to +1.2 V. The synthesizer is the first quantum-based ac voltage standard source. It uses perfectly quantized Josephson pulses to generate arbitrary waveforms with low

  15. A comparison of three CT voltage optimization strategies

    NASA Astrophysics Data System (ADS)

    Ogden, Kent M.; Huda, Walter; Khorasani, Mohammad R.; Scalzetti, Ernest M.

    2008-03-01

    We evaluated three strategies for optimizing the x-ray tube voltage in chest CT examinations: (1) keeping patient dose constant and maximizing contrast to noise ratios (CNR); (2) keeping CNR constant and minimizing patient effective dose (E); (3) maximizing CNR2/E. Lung and soft tissue Hounsfield unit values, together with the corresponding image noise, were measured in a Rando phantom at x-ray tube voltages between 80 and 140 kV. A CT dosimetry software package (ImPACT) was used to compute effective doses as a function of CT x-ray tube voltage for adult patients undergoing chest CT examinations. CNR and patient dose in chest CT examinations both increase with increasing x-ray tube voltage at a fixed mAs. All optimization strategies provided similar qualitative results, which showed the best imaging performance was achieved at the lowest x-ray tube voltage (80 kV). Optimization using constant CNR or effective dose is preferred since these methods provide explicit choices of optimal kV/mAs combinations, as well as quantitative data on how changing kV would modify CNR and/or patient dose. The CNR2/Dose figure of merit does not offer explicit choices of kV/mAs for performing CT examinations, and changes in FOM value are more difficult to relate to changes in imaging performance or patient dose.

  16. Implications of Pulser Voltage Ripple

    SciTech Connect

    Barnard, J J

    2011-12-21

    In a recent set of measurements obtained by G. Kamin, W. Manning, A. Molvik, and J. Sullivan, the voltage waveform of the diode pulser had a ripple of approximately {+-}1.3% of the 65 kV flattop voltage, and the beam current had a larger corresponding ripple of approximately {+-}8.4% of the 1.5 mA average current at the location of the second Faraday cup, approximately 1.9 m downstream from the ion source. The period of the ripple was about 1 {mu}s. It was initially unclear whether this large current ripple was in fact a true measurement of the current or a spurious measurement of noise produced by the pulser electronics. The purpose of this note is to provide simulations which closely match the experimental results and thereby corroborate the physical nature of those measurements, and to provide predictions of the amplitude of the current ripples as they propagate to the end of linear transport section. Additionally analytic estimates are obtained which lend some insight into the nature of the current fluctuations and to provide an estimate of what the maximum amplitude of the current fluctuations are expected to be, and conversely what initial ripple in the voltage source is allowed, given a smaller acceptable tolerance on the line charge density.

  17. Voltage tunable polymer laser device

    NASA Astrophysics Data System (ADS)

    Döring, Sebastian; Kollosche, Matthias; Rabe, Torsten; Kofod, Guggi; Stumpe, Joachim

    2012-03-01

    Since organic laser materials offer broad optical gain spectra they are predestined for the realization of widely tunable laser sources. Here we report on a compact organic laser device that allows for voltage controlled continuously wavelength tuning in the visible range of the spectrum by external deformation. The device consists of an elastomeric distributed feedback (DFB) laser and an electro-active elastomer actuator also known as artificial muscle. Second order DFB lasing is realized by a grating line structured elastomer substrate covered with a thin layer of dye doped polymer. To enable wavelength tuning the elastomer laser is placed at the center of the electro-active elastomer actuator. Chosen design of the actuator gives rise to homogeneous compression at this position. The voltage induced deformation of the artificial muscle is transferred to the elastomer laser and results in a decrease of grating period. This leads to an emission wavelength shift of the elastomer laser. The increase of actuation voltage to 3.25 kV decreased the emission wavelength from 604 nm to 557 nm, a change of 47 nm or 7.8%.

  18. Production of high voltage by ion bombardment 

    E-print Network

    Phinney, Lucas Carter

    2003-01-01

    A beam of He+ ions was used to bombard a conductive target, allowing the target to build up a voltage. The voltage that built up on the target was measured by using a voltage divider circuit. The target was made out of niobium metal...

  19. Energy minimization using multiple supply voltages

    Microsoft Academic Search

    Jui-ming Chang; Massoud Pedram

    1997-01-01

    We present a dynamic programming technique for solving the multiple supply voltage scheduling problem in both nonpipelined and functionally pipelined data-paths. The sched- uling problem refers to the assignment of a supply voltage level (selected from a fixed and known number of voltage levels) to each operation in a data flow graph so as to minimize the average energy consumption

  20. Characteristics of shaft voltage and bearing currents

    Microsoft Academic Search

    D. Busse; J. Erdman; R. Kerkman; D. Schlegel; G. Skibinski

    1997-01-01

    This article reviews investigations into reduced bearing life due to voltage source adjustable speed drive (ASD) AC motor operation. Relevant bearing failure mechanisms and indicators are discussed. dv\\/dt and electric discharge machining (EDM) contributions are discussed and experimental data presented showing the voltage levels on motor shafts when operating with ASDs. Finally, techniques to reduce shaft voltage are discussed, along

  1. FBG Based Voltage Measurement using PZT Modulation

    Microsoft Academic Search

    Yuan Yao; Benshun Yi

    2006-01-01

    This article proposes a new fiber Bragg grating (FBG) sensor for voltage measurement. Based on the theoretical analysis of the relationship between the PZT electrostriction displacement and the applied voltage, using the characteristic of the FBG measurement - the FBG wavelength drift can reflect the FBG radial strain, a FBG voltage sensor is designed and developed. When the DC exciting

  2. High Voltage Reed Relays for PCB

    E-print Network

    Berns, Hans-Gerd

    276 High Voltage Reed Relays for PCB Mounting HE Series MEDER electronic www.meder.com Germany surgery) High voltage Reed Relays for PCB mounting suitable for switching up to 7.5 kVDC and breakdown High Voltage Reed Relays for PCB Mounting www.meder.com Germany # ++49-(0)7733-94870, USA # 800

  3. Electrometer system measures nanoamps at high voltage

    NASA Technical Reports Server (NTRS)

    Sturman, J. C.; Sharp, G. R.; Robson, R. R.; Stevens, N. J.; Priebe, D. H. F.; Wetli, R. G.

    1974-01-01

    Floating electrometer eliminates major source of error since any leakage from electrometer case, which is at high voltage, appears only as load on high voltage supply and not as part of current being measured. Commands to and data from floating electrometer are transferred across high voltage interface by means of optical channels.

  4. Long-term evaluation of solid oxide fuel cell candidate materials in a 3-cell generic short stack fixture, Part II: sealing glass stability, microstructure and interfacial reactions.

    SciTech Connect

    Chou, Y. S.; Stevenson, Jeffry W.; Choi, Jung-Pyung

    2014-03-15

    A generic solid oxide fuel cell stack test fixture was developed to evaluate candidate materials and processing methods under realistic conditions. Part I of the work addressed the stack fixture, seal system and cell performance of a 3-cell short stack tested at 800oC for 6000h. Commercial NiO-YSZ anode-supported thin YSZ electrolyte cells with LSM cathodes were used for assessment and were tested in constant current mode with dilute (~50% H2) fuel versus air. Part II of the work examined the sealing glass stability, microstructure development, interfacial reactions, and volatility issues. Part III of the work investigated the stability of Ce-(Mn,Co) spinel coating, AISI441 metallic interconnect, alumina coating, and cell degradation. After 6000h of testing, the refractory sealing glass YSO77 (Ba-Sr-Y-B-Si) showed desirable chemical compatibility with YSZ electrolyte in that no discernable interfacial reaction was identified, consistent with thermodynamic calculations. In addition, no glass penetration into the thin electrolyte was observed. At the aluminized AISI441 interface, the protective alumina coating appeared to be corroded by the sealing glass. Air side interactions appeared to be more severe than fuel side interactions. Metal species such as Cr, Mn, and Fe were detected in the glass, but were limited to the vicinity of the interface. No alkaline earth chromates were found at the air side. Volatility was also studied in a similar glass and weight loss in a wet reducing environment was determined. Using the steady-state volatility data, the life time (40,000h) weight loss of refractory sealing glass YSO77 was estimated to be less than 0.1 wt%.

  5. Numerical analysis of stress distribution in Cu-stabilized GdBCO CC tapes during anvil tests for the evaluation of transverse delamination strength

    NASA Astrophysics Data System (ADS)

    Dizon, John Ryan C.; Gorospe, Alking B.; Shin, Hyung-Seop

    2014-05-01

    Rare-earth-Ba-Cu-O (REBCO) based coated conductors (CCs) are now being used for electric device applications. For coil-based applications such as motors, generators and magnets, the CC tape needs to have robust mechanical strength along both the longitudinal and transverse directions. The CC tape in these coils is subjected to transverse tensile stresses during cool-down and operation, which results in delamination within and between constituent layers. In this study, in order to explain the behaviour observed in the evaluation of c-axis delamination strength in Cu-stabilized GdBCO CC tapes by anvil tests, numerical analysis of the mechanical stress distribution within the CC tape has been performed. The upper anvil size was varied in the analysis to understand the effect of anvil size on stress distribution within the multilayered CC tape, which is closely related to the delamination strength, delamination mode and delamination sites that were experimentally observed. The numerical simulation results showed that, when an anvil size covering the whole tape width was used, the REBCO coating film was subjected to the largest stress, which could result in low mechanical delamination and electromechanical delamination strengths. Meanwhile, when smaller-sized anvils were used, the copper stabilizer layer would experience the largest stress among all the constituent layers of the CC tape, which could result in higher mechanical and electromechanical delamination strengths, as well as high scattering of both of these delamination strengths. As a whole, the numerical simulation results could explain the damage evolution observed in CC tapes tested under transverse tensile stress, as well as the transverse tensile stress response of the critical current, Ic.

  6. High Voltage Power Transmission for Wind Energy

    NASA Astrophysics Data System (ADS)

    Kim, Young il

    The high wind speeds and wide available area at sea have recently increased the interests on offshore wind farms in the U.S.A. As offshore wind farms become larger and are placed further from the shore, the power transmission to the onshore grid becomes a key feature. Power transmission of the offshore wind farm, in which good wind conditions and a larger installation area than an onshore site are available, requires the use of submarine cable systems. Therefore, an underground power cable system requires unique design and installation challenges not found in the overhead power cable environment. This paper presents analysis about the benefit and drawbacks of three different transmission solutions: HVAC, LCC/VSC HVDC in the grid connecting offshore wind farms and also analyzed the electrical characteristics of underground cables. In particular, loss of HV (High Voltage) subsea power of the transmission cables was evaluated by the Brakelmann's theory, taking into account the distributions of current and temperature.

  7. Stability Functions

    E-print Network

    Burns, Daniel

    In this article we discuss the role of stability functions in geometric invariant theory and apply stability function techniques to various types of asymptotic problems in the Kahler geometry of GIT quotients. We discuss ...

  8. Design and evaluation of a 3 million DN series-hybrid thrust bearing. [stability tests and fatigue tests

    NASA Technical Reports Server (NTRS)

    Scibbe, H. W.; Winn, L. W.; Eusepi, M.

    1976-01-01

    The bearing, consisting of a 150-mm ball bearing and a centrifugally actuated, conical, fluid-film bearing, was fatigue tested. Test conditions were representative of a mainshaft ball bearing in a gas turbine engine operating at maximum thrust load to simulate aircraft takeoff conditions. Tests were conducted up to 16000 rpm and at this speed an axial load of 15568 newtons (3500 lb) was safely supported by the hybrid bearing system. Through the series-hybrid bearing principle, the effective ball bearing speed was reduced to approximately one-half of the shaft speed. It was concluded that a speed reduction of this magnitude results in a ten-fold increase in the ball bearing fatigue life. A successful evaluation of fluid-film bearing lubricant supply failure was performed repeatedly at an operating speed of 10,000 rpm. A complete and smooth changeover to full-scale ball bearing operation was effected when the oil supply to the fluid-film bearing was cut off. Reactivation of the fluid-film oil supply system resulted in a flawless return to the original mode of hybrid operation.

  9. Structured superparamagnetic nanoparticles for high performance mediator of magnetic fluid hyperthermia: synthesis, colloidal stability and biocompatibility evaluation.

    PubMed

    Thorat, N D; Otari, S V; Bohara, R A; Yadav, H M; Khot, V M; Salunkhe, A B; Phadatare, M R; Prasad, A I; Ningthoujam, R S; Pawar, S H

    2014-09-01

    Core-shell structures with magnetic core and metal/polymer shell provide a new opportunity for constructing highly efficient mediator for magnetic fluid hyperthermia. Herein, a facile method is described for the synthesis of superparamagnetic LSMO@Pluronic F127 core-shell nanoparticles. Initially, the surface of the LSMO nanoparticles is functionalized with oleic acid and the polymeric shell formation is achieved through hydrophobic interactions with oleic acid. Each step is optimized to get good dispersion and less aggregation. This methodology results into core-shell formation, of average diameter less than 40 nm, which was stable under physiological conditions. After making a core-shell formulation, a significant increase of specific absorption rate (up to 300%) has been achieved with variation of the magnetization (<20%). Furthermore, this high heating capacity can be maintained in various simulated physiological conditions. The observed specific absorption rate is almost higher than Fe3O4. MTT assay is used to evaluate the toxicity of bare and core-shell MNPs. The mechanism of cell death by necrosis and apoptosis is studied with sequential staining of acridine orange and ethidium bromide using fluorescence and confocal microscopy. The present work reports a facile method for the synthesis of core-shell structure which significantly improves SAR and biocompatibility of bare LSMO MNPs, indicating potential application for hyperthermia. PMID:25063164

  10. Breakdown voltage of interelectrode gap between sphere-plane electrodes under ac voltage

    Microsoft Academic Search

    Masakazu Higashiyama; T. Hayama; S. Nakamura; T. Umemura; T. Hirose; Masayuki Hikita; Masahiro Kozako

    2010-01-01

    The breakdown voltage in a small spacing under dc voltage application has been well described with the Paschen law. The present paper differs from the previous works in that we employ ac voltage. The electrode system employed is sphere-plane electrodes and the sphere and\\/or sphere electrodes are coated with an epoxy resin. The breakdown voltage of air gap of the

  11. Voltage Sag Compensation With Z-Source Inverter Based Dynamic Voltage Restorer

    Microsoft Academic Search

    D. M. Vilathgamuwa; C. J. Gajanayake; P. C. Loh; Y. W. Li

    2006-01-01

    The dynamic voltage restorer has been gaining acceptance as an effective device for voltage sag compensation. The compensation capability of a dynamic voltage restorer (DVR) depends primarily on the maximum voltage injection ability and the amount of stored energy available within the restorer. A new topology based on Z-source inverter for the DVR is proposed in order to enhance the

  12. Low-power digital filtering using multiple voltage distribution and adaptive voltage scaling (poster session)

    Microsoft Academic Search

    Sandeep Dhar; Dragan Maksimovi?

    2000-01-01

    This paper describes an adaptive power management architecture to reduce power consumption in digital filters. The proposed approach combines two low-power techniques which utilize supply voltage reduction. The first technique, multiple voltage distribution (MVD), attempts to reduce power consumption by assigning reduced supply voltages to circuit modules while satisfying timing constraints. The second technique, adaptive voltage scaling (AVS), dynamically adjusts

  13. Transient Current Compensation for Low-voltage High-current Voltage Regulator Modules

    E-print Network

    Wu, Shin-Tson

    Transient Current Compensation for Low-voltage High-current Voltage Regulator Modules Jia Luo, Issa large voltage spike under load-change transient due to its current response delay. A new active transient current compensation is presented to limit voltage spike within 1.5% variation in load- change

  14. Medium voltage motor harmonic heating, torques and voltage stress when applied on VFDs

    Microsoft Academic Search

    Frank A. DeWinter; Bin Wu

    1996-01-01

    The increase in the application of medium voltage variable frequency drives to AC motors has raised concerns regarding the effects the drives have on the motors. Most of the published data available is for low voltage motors and drives, which are not necessarily accurate for the medium voltage applications. We address the harmonic heating, torques and voltage stress that are

  15. Electrophoretic deposition behavior of ceria-stabilized zirconia/alumina powder.

    PubMed

    Nakamura, Takashi; Nishida, Hisataka; Sekino, Tohru; Nawa, Masahiro; Wakabayashi, Kazumichi; Kinuta, Soichiro; Mutobe, Yoshihiko; Yatani, Hirofumi

    2007-09-01

    The aim of this study was to evaluate the electrophoretic deposition (EPD) behavior of ceria-stabilized zirconia/alumina (Ce-TZP/Al2O3) granulated powder. Two types of slurry with powder-to-solvent ratios of 10 wt% and 20 wt% were used. Zeta potential of the slurries was measured using a spectrometer at different pH levels. Then, EPD was performed to measure the weight of the deposited particles at varying pH levels and at two voltages (50 V and 100 V). The isoelectric point of Ce-TZP/Al2O3 mixed powder was approximately at pH 8.5. When EPD was performed, deposition of ceramic particles was typically observed in the range of pH 3 to pH 7, with the greatest deposition found at around pH 7. Moreover, the deposition of ceramic particles increased with increase in slurry concentration and voltage. PMID:18203459

  16. Stabilized Vegas

    Microsoft Academic Search

    Hyojeong Choe; Steven H. Low

    2003-01-01

    We show that the current TCP Vegas algorithm can become unstable in the presence of network delay and propose a modification that stabilizes it. The stabilized Vegas remains completely source-based and can be implemented without any network support. We suggest an incremental deployment strategy for stabilized Vegas when the network contains a mix of links, some with active queue management

  17. An evaluation of the stability of image-quality parameters of Varian on-board imaging (OBI) and EPID imaging systems.

    PubMed

    Stanley, Dennis N; Papanikolaou, Nikos; Gutierrez, Alonso N

    2015-01-01

    Quality assurance (QA) of the image quality for image-guided localization systems is crucial to ensure accurate visualization and localization of regions of interest within the patient. In this study, the temporal stability of selected image parameters was assessed and evaluated for kV CBCT mode, planar radiographic kV, and MV modes. The motivation of the study was to better characterize the temporal variability in specific image-quality parameters. The CATPHAN, QckV-1, and QC-3 phantoms were used to evaluate the image-quality parameters of the imaging systems on a Varian Novalis Tx linear accelerator. The planar radiographic images were analyzed in PIPSpro with high-contrast spatial resolution (f30, f40,f50 lp/mm) being recorded. For OBI kV CBCT, high-quality head full-fan acquisition and pelvis half-fan acquisition modes were evaluated for uniformity, noise, spatial resolution, HU constancy, and geometric distortion. Dose and X-ray energy for the OBI were recorded using the Unfors RaySafe Xi system with the R/F High Detector for kV planar radiographic and the CT detector for kV CBCT. Dose for the MV EPID was recorded using a PTW975 Semiflex ion chamber, PTW UNIDOS electrometer, and CNMC Plastic Water. For each image-quality parameter, values were normalized to the mean, and the normalized standard deviations were recorded to evaluate the parameter's temporal variability. For planar radiographic modes, the normalized standard deviations of the spatial resolution (f30, f40, & f50) were 0.015, 0.008, 0.004 lp/mm and 0.006, 0.009, 0.018 lp/mm for the kV and MV, respectively. The normalized standard deviation of dose for kV and MV were 0.010 mGy and 0.005mGy, respectively. The standard deviations for full- and half-fan kV CBCT modes were averaged together. The following normalized standard deviations for each kV CBCT parameter were: 0.075 HU (uniformity), 0.071 HU (noise), 0.006mm (AP-geometric distortion), 0.005 mm (LAT-geometric distortion), 0.058mm (slice thickness), 0.124 (f50), 0.031 (HU constancy - Lung), 0.063 (HU constancy- Water), 0.020 (HU constancy - Bone), 0.006 mGy (Dose - Center), 0.004 mGy (Dose -Periphery). Using control chart analysis, institutional QA tolerances were reported as warning and action thresholds based on 1? and 2? thresholds. A study was performed to characterize the stability of image-quality parameters recommended by AAPM Task Group-142 for the Varian OBI and EPID imaging systems. Both imaging systems show consistent imaging and dosimetric properties over the evaluated time frame. PMID:26103178

  18. A case study of voltage-gated potassium channel antibody-related limbic encephalitis with PET/MRI findings

    PubMed Central

    Day, Brian K.; Eisenman, Lawrence; Black, Joseph; Maccotta, Luigi; Hogan, R. Edward

    2015-01-01

    Preclinical and clinical studies have demonstrated the significance of inflammation and autoantibodies in epilepsy, and the use of immunotherapies in certain situations has become an established practice. Temporal lobe epilepsy can follow paraneoplastic or nonparaneoplastic limbic encephalitis associated with antibodies directed against brain antigens. Here, we focus on a patient with worsening confusion and temporal lobe seizures despite treatment with antiepileptic medications. Serial brain MRIs did not conclusively reveal structural abnormalities, so the patient underwent brain PET/MRI to simultaneously evaluate brain structure and function, revealing bitemporal abnormalities. The patient was diagnosed with voltage-gated potassium channel antibody-related limbic encephalitis based on clinical presentation, imaging findings, and antibody testing. Treatment included the addition of a second antiepileptic agent and oral steroids. His seizures and cognitive deficits improved and stabilized.

  19. Dynamic threshold-voltage MOSFET (DTMOS) for ultra-low voltage VLSI

    Microsoft Academic Search

    Fariborz Assaderaghi; Dennis Sinitsky; Stephen A. Parke; Jeffrey Bokor; Ping K. Ko; Chenming Hu

    1997-01-01

    In this paper, we propose a novel operation of a MOSFET that is suitable for ultra-low voltage (0.6 V and below) VLSI circuits. Experimental demonstration was carried out in a Silicon-On-Insulator (SOI) technology. In this device, the threshold voltage of the device is a function of its gate voltage, i.e., as the gate voltage increases the threshold voltage (Vt) drops

  20. A dynamic threshold voltage MOSFET (DTMOS) for ultra-low voltage operation

    Microsoft Academic Search

    F. Assaderaghi; D. Sinitsky; S. Parke; J. Bokor; P. K. Ko; Chenming Hu

    1994-01-01

    To extend the lower bound of power supply to ultra-low voltages (0.6 V and below), we propose a dynamic-threshold voltage MOSFET (DTMOS) built on silicon-on-insulator (SOI). The threshold voltage of DTMOS drops as the gate voltage is raised, resulting in a much higher current drive than standard MOSFET at low power supply voltages. On the other hand, Vt is high