Science.gov

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. Memristor-integrated voltage-stabilizing supercapacitor system.

    PubMed

    Liu, Bin; Liu, Boyang; Wang, Xianfu; Wu, Xinghui; Zhao, Wenning; Xu, Zhimou; Chen, Di; Shen, Guozhen

    2014-08-01

    Voltage-stabilized supercapacitors: A single supercapacitor formed with PCBM/Pt/IPS nanorod-array electrodes is designed and delivers enhanced areal capacitance, capacitance retention, and excellent electrical stability under bending, while a significant voltage-decrease is observed during the discharging process. Once integrated with the memristor, the memristor-integrated supercapacitor systems deliver an extremely low voltage-drop, indicating greatly enhanced voltage-stabilizing features. PMID:24805149

  3. Long term voltage stability analysis for small disturbances 

    E-print Network

    Men, Kun

    2009-05-15

    stability margin accurately and efficiently at a reasonable cost, especially for large system. Considering the first challenge, this dissertation applied eigenvalue based bifurcation analysis to allocate the contribution of voltage stability. We investigate...

  4. A Review of Voltage Stability Assessment Techniques with an Improved Voltage Stability Indicator

    NASA Astrophysics Data System (ADS)

    Danish, Mir Sayed Shah; Yona, Atsushi; Senjyu, Tomonobu

    2015-04-01

    A blackout can take place in entire power system or a part of the system due to extreme voltage instability (voltage collapse) that can appear abruptly. Instability prediction and continuous monitoring of the power system performance is, therefore, known exigent. This paper is conducted with a broad overview of the voltage stability indices, which are previously studied in the literature, and have the same foundation during their formulation. Afterward, an improved voltage stability indicator is introduced as a result of the multi-criteria integration and enhancement of the original indices by employing linear algebra methods. It is found that the proposed algorithm can overcome on the probable limitations from calculating point view. Then comparative analysis of the indices is presented in order to reach a unique consensus about the typical techniques of modal analysis (sensitivity, eigenvalue, right eigenvectors, and bus participation factor) as a precise algorithm. Finally, the IEEE 14-bus, and 30-bus test systems are selected to verify the algorithm, and compare the performance of the improved indicator approach with the existing indices.

  5. Voltage stability and controllability indices for multimachine power systems

    SciTech Connect

    Vournas, C.D.

    1995-08-01

    This paper presents a voltage stability index (VSI) and a voltage controllability index (VCI), related to the eigenvalues of mxm matrices in a multimachine power system made up of m synchronous generators and a number of infinite buses. System loads can have an arbitrary voltage sensitivity described by generalized voltage exponents. These nonlinear loads are linearized around an operating point and incorporated into a modified admittance matrix, which is subsequently reduced to the generator terminals using an efficient algorithm and sparsity techniques. The indices proposed are tested in a practical system and it is demonstrated that they provide a timely warning during a sequence of events leading to voltage collapse.

  6. Contribution Allocation for Voltage Stability In Deregulated Power Systems

    E-print Network

    and one load bus system is used to demonstrate our approach. The system has three basic parts of the power--P- controller, PI-controller and PID controller of a voltage regulator, the load flow equation of this systemContribution Allocation for Voltage Stability In Deregulated Power Systems Garng M. Huang, Senior

  7. Optimal Placement of Unified Power Flow Controllers to Improve Dynamic Voltage Stability Using Power System Variable Based Voltage Stability Indices

    PubMed Central

    Albatsh, Fadi M.; Ahmad, Shameem; Mekhilef, Saad; Mokhlis, Hazlie; Hassan, M. A.

    2015-01-01

    This study examines a new approach to selecting the locations of unified power flow controllers (UPFCs) in power system networks based on a dynamic analysis of voltage stability. Power system voltage stability indices (VSIs) including the line stability index (LQP), the voltage collapse proximity indicator (VCPI), and the line stability index (Lmn) are employed to identify the most suitable locations in the system for UPFCs. In this study, the locations of the UPFCs are identified by dynamically varying the loads across all of the load buses to represent actual power system conditions. Simulations were conducted in a power system computer-aided design (PSCAD) software using the IEEE 14-bus and 39- bus benchmark power system models. The simulation results demonstrate the effectiveness of the proposed method. When the UPFCs are placed in the locations obtained with the new approach, the voltage stability improves. A comparison of the steady-state VSIs resulting from the UPFCs placed in the locations obtained with the new approach and with particle swarm optimization (PSO) and differential evolution (DE), which are static methods, is presented. In all cases, the UPFC locations given by the proposed approach result in better voltage stability than those obtained with the other approaches. PMID:25874560

  8. Optimal placement of unified power flow controllers to improve dynamic voltage stability using power system variable based voltage stability indices.

    PubMed

    Albatsh, Fadi M; Ahmad, Shameem; Mekhilef, Saad; Mokhlis, Hazlie; Hassan, M A

    2015-01-01

    This study examines a new approach to selecting the locations of unified power flow controllers (UPFCs) in power system networks based on a dynamic analysis of voltage stability. Power system voltage stability indices (VSIs) including the line stability index (LQP), the voltage collapse proximity indicator (VCPI), and the line stability index (Lmn) are employed to identify the most suitable locations in the system for UPFCs. In this study, the locations of the UPFCs are identified by dynamically varying the loads across all of the load buses to represent actual power system conditions. Simulations were conducted in a power system computer-aided design (PSCAD) software using the IEEE 14-bus and 39- bus benchmark power system models. The simulation results demonstrate the effectiveness of the proposed method. When the UPFCs are placed in the locations obtained with the new approach, the voltage stability improves. A comparison of the steady-state VSIs resulting from the UPFCs placed in the locations obtained with the new approach and with particle swarm optimization (PSO) and differential evolution (DE), which are static methods, is presented. In all cases, the UPFC locations given by the proposed approach result in better voltage stability than those obtained with the other approaches. PMID:25874560

  9. RESEARCH ARTICLE Interpolation approximation of voltage stability

    E-print Network

    Tolbert, Leon M.

    optimal power flow (VSCOPF); reactive power planning (RPP); total transfer capability (TTC); stability The US power industry has been under great pressure to serve load economically since deregulation, reactive power, a critical need for power system operation and planning, has received less attention until

  10. Voltage-Tunable Magnetic Stability in a Ni Nanoparticle

    NASA Astrophysics Data System (ADS)

    Gartland, Patrick; Jiang, Wenchao; Davidovic, Dragomir

    2015-03-01

    We study single nickel particles ~ 2 nm in diameter using single electron tunneling spectroscopy and find that such particles lie at the threshold of stable ferromagnetic order. We find that the application of a bias voltage can precisely tune the conditions for a stable magnetization orientation, and simulate the experimental configuration using a master equation. Due to the addition of anisotropy from a single electron, a new energy scale emerges which governs the stability of magnetization as a function of voltage bias conditions. Department of Energy Grand DE-FG02-06ER46281.

  11. Concepts of undervoltage load shedding for voltage stability

    SciTech Connect

    Taylor, C.W. )

    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.

  12. Impact of Cyber Attacks on Transient Stability of Smart Grids with Voltage Support Devices

    E-print Network

    Kundur, Deepa

    devices, SVC and STATCOM, in an 8-bus test system. The 8 bus system and voltage devices are simulated--cyber attack, cyber security, smart grids, SVC, STATCOM, FACTS, transient stability, voltage support device I

  13. On the Configuration of the US Western Interconnection Voltage Stability Boundary

    SciTech Connect

    Makarov, Yuri V.; Vyakaranam, Bharat; Wu, Di; Hou, Zhangshuan; Elbert, Stephen T.; Huang, Zhenyu

    2014-04-01

    Abstract—Stability limits are considered in power system planning and operations to estimate the available stability margins and, if possible, to maximize the utilization of transmission facilities. These important tasks are influenced by configuration of the stability boundary. The paper introduces a new fast approach to explore the voltage stability boundary of a large system and reveal its detailed multidimensional structure. The 17939-bus U.S. Western Interconnection planning model was used to illustrate the method. Significant peculiarities of the boundary’s configuration were identified, including its nonconvexity, discontinuity, branching and internal singularities (“holes”) that were not known before and could not been found by traditional methods. Experiments using WECC system are performed to evaluate the computation time using different methods. Our results show that the proposed methods are very promising in reducing calculation time and complexity

  14. Strategies for Voltage Control and Transient Stability Assessment

    SciTech Connect

    Hiskens, Ian A.

    2013-09-25

    As wind generation grows, its influence on power system performance will becoming increasingly noticeable. Wind generation di#11;ffers from traditional forms of generation in numerous ways though, motivating the need to reconsider the usual approaches to power system assessment and performance enhancement. The project has investigated the impact of wind generation on transient stability and voltage control, identifying and addressing issues at three distinct levels of the power system: 1) at the device level, the physical characteristics of wind turbine generators (WTGs) are quite unlike those of synchronous machines, 2) at the wind-farm level, the provision of reactive support is achieved through coordination of numerous dissimilar devices, rather than straightforward generator control, and 3) from a systems perspective, the location of wind-farms on the sub-transmission network, coupled with the variability inherent in their power output, can cause complex voltage control issues. The project has sought to develop a thorough understanding of the dynamic behaviour of type-3 WTGs, and in particular the WECC generic model. The behaviour of such models is governed by interactions between the continuous dynamics of state variables and discrete events associated with limits. It was shown that these interactions can be quite complex, and may lead to switching deadlock that prevents continuation of the trajectory. Switching hysteresis was proposed for eliminating deadlock situations. Various type-3 WTG models include control blocks that duplicate integrators. It was shown that this leads to non-uniqueness in the conditions governing steady-state, and may result in pre- and post-disturbance equilibria not coinciding. It also gives rise to a zero eigenvalue in the linearized WTG model. In order to eliminate the anomalous behaviour revealed through this investigation, WECC has now released a new generic model for type-3 WTGs. Wind-farms typically incorporate a variety of voltage control equipment including tapchanging transformers, switched capacitors, SVCs, STATCOMs and the WTGs themselves. The project has considered the coordinated control of this equipment, and has addressed a range of issues that arise in wind-farm operation. The #12;first concerns the ability of WTGs to meet reactive power requirements when voltage saturation in the collector network restricts the reactive power availability of individual generators. Secondly, dynamic interactions between voltage regulating devices have been investigated. It was found that under certain realistic conditions, tap-changing transformers may exhibit instability. In order to meet cost, maintenance, fault tolerance and other requirements, it is desirable for voltage control equipment to be treated as an integrated system rather than as independent devices. The resulting high-level scheduling of wind-farm reactive support has been investigated. In addressing this control problem, several forms of future information were considered, including exact future knowledge and stochastic predictions. Deterministic and Stochastic Dynamic Programming techniques were used in the development of control algorithms. The results demonstrated that while exact future knowledge is very useful, simple prediction methods yield little bene#12;fit. The integration of inherently variable wind generation into weak grids, particularly subtransmission networks that are characterized by low X=R ratios, aff#11;ects bus voltages, regulating devices and line flows. The meshed structure of these networks adds to the complexity, especially when wind generation is distributed across multiple nodes. A range of techniques have been considered for analyzing the impact of wind variability on weak grids. Sensitivity analysis, based on the power-flow Jacobian, was used to highlight sections of a system that are most severely a#11;ffected by wind-power variations. A continuation power flow was used to determine parameter changes that reduce the impact of wind-power variability. It was also used to explore interactions betw

  15. 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.

  16. Coordinated Dynamic Voltage Stabilization based on Model Predictive Control

    E-print Network

    Kumar, Ratnesh

    (STATCOMs) to improve voltage profile and to re- duce the mechanical switching operations within network based coordination control scheme for ULTCs and STATCOMs to minimize the amount of trans- former tap changes and STATCOM outputs while maintaining acceptable voltage magnitudes at substation buses

  17. A New Bifurcation Analysis for Power System Dynamic Voltage Stability Studies

    E-print Network

    and compared. It is shown that the unreduced Jacobian matrix, whose eigen-structure matches well of the voltage stability is studied, some equations of the generator rotor will not be considered. For a fixed

  18. 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.

  19. Automated Evaluation of Dynamic Performance of Impulse Voltage Measurement Systems

    NASA Astrophysics Data System (ADS)

    Faria, L. C.; Silva, E. C.; Silva, M. T.; Barbosa, C. R. H.; Azevedo, L. C.

    2015-01-01

    This manuscript presents and describes an automated system for the evaluation of the dynamic performance of high-voltage measurement systems, according to the requirements of the standard IEC 60060-2/2010. The system was developed in LabVIEW and controls the acquisition, measurement and analysis of step response tests of measurement systems, automatically calculating the relevant amplitude and time parameters.

  20. Stabilization of Gyrotron Frequency by PID Feedback Control on the Acceleration Voltage

    NASA Astrophysics Data System (ADS)

    Khutoryan, E. M.; Idehara, T.; Kuleshov, A. N.; Tatematsu, Y.; Yamaguchi, Y.; Matsuki, Y.; Fujiwara, T.

    2015-12-01

    The results of frequency stabilization by proportional-integral-derivative (PID) feedback control of acceleration voltage in the 460-GHz Gyrotron FU CW GVI (the official name in Osaka University is Gyrotron FU CW GOI) are presented. The experiment was organized on the basis of the frequency modulation by modulation of acceleration voltage of beam electrons. The frequency stabilization during 10 h experiment was better than 10-6, which is compared with the results of the frequency deviation in free-running gyrotron operation.

  1. Voltage Stability Impact of Grid-Tied Photovoltaic Systems Utilizing Dynamic Reactive Power Control

    NASA Astrophysics Data System (ADS)

    Omole, Adedamola

    Photovoltaic (PV) DGs can be optimized to provide reactive power support to the grid, although this feature is currently rarely utilized as most DG systems are designed to operate with unity power factor and supply real power only to the grid. In this work, the voltage stability of a power system embedded with PV DG is examined in the context of the high reactive power requirement after a voltage sag or fault. A real-time dynamic multi-function power controller that enables renewable source PV DGs to provide the reactive power support necessary to maintain the voltage stability of the microgrid, and consequently, the wider power system is proposed. The loadability limit necessary to maintain the voltage stability of an interconnected microgrid is determined by using bifurcation analysis to test for the singularity of the network Jacobian and load differential equations with and without the contribution of the DG. The maximum and minimum real and reactive power support permissible from the DG is obtained from the loadability limit and used as the limiting factors in controlling the real and reactive power contribution from the PV source. The designed controller regulates the voltage output based on instantaneous power theory at the point-of-common coupling (PCC) while the reactive power supply is controlled by means of the power factor and reactive current droop method. The control method is implemented in a modified IEEE 13-bus test feeder system using PSCADRTM power system analysis software and is applied to the model of a Tampa ElectricRTM PV installation at Lowry Park Zoo in Tampa, FL. This dissertation accomplishes the systematic analysis of the voltage impact of a PV DG-embedded power distribution system. The method employed in this work bases the contribution of the PV resource on the voltage stability margins of the microgrid rather than the commonly used loss-of-load probability (LOLP) and effective load-carrying capability (ELCC) measures. The results of the proposed method show good improvement in the before-, during-, and post-start voltage levels at the motor terminals. The voltage stability margin approach provides the utility a more useful measure in sizing and locating PV resources to support the overall power system stability in an emerging smart grid.

  2. Stability issues in IC Low Drop Out voltage regulators 

    E-print Network

    Chava, Krishna Chaitanya

    2002-01-01

    regulators, and improves transient response and noise performance. Test results from the prototype provide an evaluation of the most important parameters of the regulator: ground current, load regulation, line regulation, output noise and start-up time....

  3. Organic thin film devices with stabilized threshold voltage and mobility, and method for preparing the devices

    DOEpatents

    Nastasi, Michael Anthony; Wang, Yongqiang; Fraboni, Beatrice; Cosseddu, Piero; Bonfiglio, Annalisa

    2013-06-11

    Organic thin film devices that included an organic thin film subjected to a selected dose of a selected energy of ions exhibited a stabilized mobility (.mu.) and threshold voltage (VT), a decrease in contact resistance R.sub.C, and an extended operational lifetime that did not degrade after 2000 hours of operation in the air.

  4. TCSC as a Transient Voltage Stabilizing Controller Garng Huang and Tong Zhu

    E-print Network

    and to mitigate the sub-synchronous resonance by regulating real power and maximizing transient synchronizing drawback that infinitive bus is not a good model for a generator for voltage stability studies since only that the generator field current limiting action limits the output of the reactive power, which is essential

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

    E-print Network

    using power flow analysis methods. In this paper, a method for online monitoring of a power system based to find the most vulnerable area in a system, to find the impacts of other loads, areas and powerMeasurement based Voltage Stability Monitoring of Power system Garng M. Huang huang

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

    E-print Network

    Lemmon, Michael

    between a bus' short-circuit power and its coupled generator's power rating. As a consequence this perspective, a network weakness parameter called short-circuit ra- tio (SCR) is defined in [18], as the ratioVoltage Stability and Frequency Synchronization of Weak Power Distribution Networks with Inverter

  7. Abstract--This paper reports a method to evaluate composite power system reliability indices incorporating the voltage

    E-print Network

    to incorporate security features to maintain an acceptable level of system reliability. A power flow can have3 Abstract--This paper reports a method to evaluate composite power system reliability indices power flow (OPF) computation algorithm, considering the steady state voltage stability margin constraint

  8. Gyrotron Output Power Stabilization by PID Feedback Control of Heater Current and Anode Voltage

    NASA Astrophysics Data System (ADS)

    Khutoryan, E. M.; Idehara, T.; Kuleshov, A. N.; Ueda, K.

    2014-12-01

    To provide stable output power of a gyrotron during long operation time the power stabilization was achieved by two schemes with PID feedback control of heater current and anode voltage. It was based on the dependence of the output power on both the anode voltage and the beam current and also on the dependence of the beam current on the gun heater current. Both schemes provided decrease of the power standard deviation to 0.3-0.5%. The comparison between parameters of both schemes is discussed in the paper.

  9. Development of real-time voltage stability monitoring tool for power system transmission network using Synchrophasor data

    NASA Astrophysics Data System (ADS)

    Pulok, Md Kamrul Hasan

    Intelligent and effective monitoring of power system stability in control centers is one of the key issues in smart grid technology to prevent unwanted power system blackouts. Voltage stability analysis is one of the most important requirements for control center operation in smart grid era. With the advent of Phasor Measurement Unit (PMU) or Synchrophasor technology, real time monitoring of voltage stability of power system is now a reality. This work utilizes real-time PMU data to derive a voltage stability index to monitor the voltage stability related contingency situation in power systems. The developed tool uses PMU data to calculate voltage stability index that indicates relative closeness of the instability by producing numerical indices. The IEEE 39 bus, New England power system was modeled and run on a Real-time Digital Simulator that stream PMU data over the Internet using IEEE C37.118 protocol. A Phasor data concentrator (PDC) is setup that receives streaming PMU data and stores them in Microsoft SQL database server. Then the developed voltage stability monitoring (VSM) tool retrieves phasor measurement data from SQL server, performs real-time state estimation of the whole network, calculate voltage stability index, perform real-time ranking of most vulnerable transmission lines, and finally shows all the results in a graphical user interface. All these actions are done in near real-time. Control centers can easily monitor the systems condition by using this tool and can take precautionary actions if needed.

  10. 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.

  11. Using Controlled Shunt Reactors for Voltage Stabilization on the Example of Real Electric Power System

    NASA Astrophysics Data System (ADS)

    Gusev, A. S.; Suvorov, A. A.; Sulaymanov, A. O.

    2015-10-01

    The article is devoted to actual task of real-time simulation controlled shunt reactors to use in the appropriate electric power system. Such development allows fully and reliably reproducing the processes running in controlled shunt reactors and electric power systems as whole. As an example of such task solution the working results of controlled shunt reactors simulation and its application for voltage stabilization are presented.

  12. Energy functions, transient stability and voltage behaviour in power systems with nonlinear loads

    SciTech Connect

    Hiskens, I.A.; Hill, D.J. )

    1989-11-01

    This paper presents preliminary results in a program aimed at energy function analysis of transient behaviour of power systems with nonlinear loads. The model, which preserves the network structure, is of differential-algebraic type. This introduces some new analytical issues, but the concepts enable the establishment of a connection between transient (angle) stability, multiple stable equilibria and voltage behaviour. A practical method for determining and classifying equilibrium points of the model is developed.

  13. IEEE TRANSACTIONS ON POWER SYSTEMS, VOL. XX, NO. Y, MONTH 2001 1 Global Transient Stability and Voltage Regulation

    E-print Network

    Guo, Yi

    stability. It con- cerns the maintenance of synchronism between generators following a severe disturbance and Voltage Regulation for Power Systems Yi Guo, David J. Hill and Youyi Wang Abstract| This paper concerns and voltage regulation are both important properties of power system control, but they are ascribed to di#11

  14. A Novel Neutral Point Potential Stabilization Technique Using the Information of Output Current Polarities and Voltage Vector

    E-print Network

    Hava, Ahmet

    A Novel Neutral Point Potential Stabilization Technique Using the Information of Output Current- This paper proposes a new neutral point potential control technique for the three-level neutral the redundant voltage vectors in a manner to obtain stable neutral point voltage under all operating conditions

  15. 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.

  16. 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...

  17. Effect of voltage current characteristic smoothness on the stability margin of cable-in-conduit conductors

    NASA Astrophysics Data System (ADS)

    Lelekhov, S. A.; Naumov, P. G.

    2007-03-01

    Experimental and numerical investigation of the AC losses induced by the transient magnet field (TMF) in cable-in-conduit conductors (CICC) revealed some interesting results. First of all, the critical current in the strands could be exceeded as a result of simultaneous increase of the strand temperature due to AC losses and the addition of the induced shielding currents to the transport current. Secondly, after the sample reaches its critical state the energy stored in the loops formed by the superconducting strands and normal "matrix" quickly dissipates in the normal matrix of the strands and in the normal "matrix" of the bundle. This results in a step increase of the conductor temperature. It was logical to assume that during the process preceding the occurrence of the first flux-jump, the maximum temperature and shielding current could depend on the smoothness of the voltage-current characteristic (VCC) of the superconducting strands. In other words, the smoothness of the VCC of the superconducting strands should influence the stability margin of a conductor. A numerical investigation of the VCC smoothness effect on stability margin was carried out for a wide range of the Stekly parameter, ?, and varying the dimensionless transport current i = It/ Ic (0 ? ? < 50; 0 ? i < 1). As a result of these calculations, it was found that the energy necessary for the first flux-jump to occur, grows as the VCC smoothness increases, when the Stekly parameter lies in the range 0 ? ? < 1, and the stability margin of a conductor decreases as the VCC smoothness increases, when the Stekly parameter ? ? 1.

  18. Abstract--This paper investigates the effect of Thyristor Controlled Series Capacitor (TCSC) on the voltage stability

    E-print Network

    is to minimize power system load curtailment. Incorporating TCSC affects the topology and hence the power flow-- Load Curtailment, OPF, Voltage Stability, TCSC. I. INTRODUCTION In the deregulated power systems,10,11]. However, the use of TCSC in redistributing power flow and its effect on load curtailment has also been

  19. 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.

  20. Wind Farm Stabilization by using DFIG with Current Controlled Voltage Source Converters Taking Grid Codes into Consideration

    NASA Astrophysics Data System (ADS)

    Okedu, Kenneth Eloghene; Muyeen, S. M.; Takahashi, Rion; Tamura, Junji

    Recent wind farm grid codes require wind generators to ride through voltage sags, which means that normal power production should be re-initiated once the nominal grid voltage is recovered. However, fixed speed wind turbine generator system using induction generator (IG) has the stability problem similar to the step-out phenomenon of a synchronous generator. On the other hand, doubly fed induction generator (DFIG) can control its real and reactive powers independently while being operated in variable speed mode. This paper proposes a new control strategy using DFIGs for stabilizing a wind farm composed of DFIGs and IGs, without incorporating additional FACTS devices. A new current controlled voltage source converter (CC-VSC) scheme is proposed to control the converters of DFIG and the performance is verified by comparing the results with those of voltage controlled voltage source converter (VC-VSC) scheme. Another salient feature of this study is to reduce the number of proportionate integral (PI) controllers used in the rotor side converter without degrading dynamic and transient performances. Moreover, DC-link protection scheme during grid fault can be omitted in the proposed scheme which reduces overall cost of the system. Extensive simulation analyses by using PSCAD/EMTDC are carried out to clarify the effectiveness of the proposed CC-VSC based control scheme of DFIGs.

  1. Genetic Algorithm Used for Load Shedding Based on Sensitivity to Enhance Voltage Stability

    NASA Astrophysics Data System (ADS)

    Titare, L. S.; Singh, P.; Arya, L. D.

    2014-12-01

    This paper presents an algorithm to calculate optimum load shedding with voltage stability consideration based on sensitivity of proximity indicator using genetic algorithm (GA). Schur's inequality based proximity indicator of load flow Jacobian has been selected, which indicates system state. Load flow Jacobian of the system is obtained using Continuation power flow method. If reactive power and active rescheduling are exhausted, load shedding is the last line of defense to maintain the operational security of the system. Load buses for load shedding have been selected on the basis of sensitivity of proximity indicator. The load bus having large sensitivity is selected for load shedding. Proposed algorithm predicts load bus rank and optimum load to be shed on load buses. The algorithm accounts inequality constraints not only in present operating conditions, but also for predicted next interval load (with load shedding). Developed algorithm has been implemented on IEEE 6-bus system. Results have been compared with those obtained using Teaching-Learning-Based Optimization (TLBO), particle swarm optimization (PSO) and its variant.

  2. Evaluation of the thermal stability of Gardasil.

    PubMed

    Shank-Retzlaff, Mary L; Zhao, Qinjian; Anderson, Carrie; Hamm, Melissa; High, Katrina; Nguyen, Mai; Wang, Feng; Wang, Ning; Wang, Bei; Wang, Yang; Washabaugh, Michael; Sitrin, Robert; Shi, Li

    2006-01-01

    The thermostability of GARDASIL (Merck & Co., Inc, Whitehouse Station, NJ, USA), a developmental vaccine against human papillomavirus (HPV), was evaluated using an enzyme immunoassay, referred to as the in vitro relative potency (IVRP) assay and differential scanning calorimetry (DSC). Gardasil samples were stored at temperatures ranging from 4 to 42 degrees C and tested for IVRP at various time points. Extrapolation of the IVRP results indicates GARDASIL is extremely stable. The half-life of the vaccine is estimated to be 130 months or longer at temperatures up to 25 degrees C. At 37 degrees C, the half-life is predicted to be 18 months and at 42 degrees C, the half-life is predicted to be approximately three months. Differential scanning calorimetry (DSC) analysis was used to evaluate the process of protein denaturation during a rapid temperature increase (as opposed to long-term storage at a specific temperature). Differences were seen among the DSC profiles of the four HPV types tested. This indicates that small differences in the amino acid structure can have a significant effect on the intermolecular contacts that stabilize the L1 proteins and the VLP assembly. For the Gardasil samples evaluated here, DSC results demonstrated the relative overall structural stability of the VLPs, but were not predictive of the excellent long-term stability observed with the IVRP assay. PMID:17012891

  3. 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.

  4. Security Constrained Coordinated Dynamic Voltage Stabilization based on Model Predictive Control

    E-print Network

    Kumar, Ratnesh

    com- pensators (STATCOMs) to improve voltage profiles and to reduce mechanical switching operations neural network based coordination control scheme for ULTCs and STATCOMs to minimize the amount of trans- former tap changes and STATCOM outputs while maintaining acceptable voltage magnitudes at substation

  5. Evaluation of high temperature dielectric films for high voltage power electronic applications

    NASA Technical Reports Server (NTRS)

    Suthar, J. L.; Laghari, J. R.

    1992-01-01

    Three high temperature films, polyimide, Teflon perfluoroalkoxy and poly-P-xylene, were evaluated for possible use in high voltage power electronic applications, such as in high energy density capacitors, cables and microelectronic circuits. The dielectric properties, including permittivity and dielectric loss, were obtained in the frequency range of 50 Hz to 100 kHz at temperatures up to 200 C. The dielectric strengths at 60 Hz were determined as a function of temperature to 250 C. Confocal laser microscopy was performed to diagnose for voids and microimperfections within the film structure. The results obtained indicate that all films evaluated are capable of maintaining their high voltage properties, with minimal degradation, at temperatures up to 200 C. However, above 200 C, they lose some of their electrical properties. These films may therefore become viable candidates for high voltage power electronic applications at high temperatures.

  6. 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

    2015-07-14

    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

  7. 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.

  8. Evaluating the Field Emission Characteristics of Aluminum for DC High Voltage Photo-Electron Guns

    NASA Astrophysics Data System (ADS)

    Taus, Rhys; Poelker, Matthew; Forman, Eric; Mamun, Abdullah

    2013-10-01

    High current photoguns require high power laser light, but only a small portion of the laser light illuminating the photocathode produces electron beam. Most of the laser light (~ 65%) simply serves to heat the photocathode, which leads to evaporation of the chemicals required to create the negative electron affinity condition necessary for photoemission. Photocathode cooling techniques have been employed to address this problem, but active cooling of the photocathode is complicated because the cooling apparatus must float at high voltage. This work evaluates the field emission characteristics of cathode electrodes manufactured from materials with high thermal conductivity: aluminum and copper. These electrodes could serve as effective heat sinks, to passively cool the photocathode that resides within such a structure. However, literature suggests ``soft'' materials like aluminum and copper are ill suited for photogun applications, due to excessive field emission when biased at high voltage. This work provides an evaluation of aluminum and copper electrodes inside a high voltage field emission test stand, before and after coating with titanium nitride (TiN), a coating that enhances surface hardness. National Science Foundation Award Number: 1062320 and the Department of Defence ASSURE program.

  9. Evaluating the Field Emission Characteristics of Aluminum for DC High Voltage Photo-Electron Guns

    NASA Astrophysics Data System (ADS)

    Taus, Rhys; Poelker, Matthew; Forman, Eric; Mamun, Abdullah

    2014-03-01

    High current photoguns require high power laser light, but only a small portion of the laser light illuminating the photocathode produces electron beam. Most of the laser light (~ 65%) simply serves to heat the photocathode, which leads to evaporation of the chemicals required to create the negative electron affinity condition necessary for photoemission. Photocathode cooling techniques have been employed to address this problem, but active cooling of the photocathode is complicated because the cooling apparatus must float at high voltage. This work evaluates the field emission characteristics of cathode electrodes manufactured from materials with high thermal conductivity: aluminum and copper. These electrodes could serve as effective heat sinks, to passively cool the photocathode that resides within such a structure. However, literature suggests ``soft'' materials like aluminum and copper are ill suited for photogun applications, due to excessive field emission when biased at high voltage. This work provides an evaluation of aluminum and copper electrodes inside a high voltage field emission test stand, before and after coating with titanium nitride (TiN), a coating that enhances surface hardness. National Science Foundation Award Number: 1062320 and the Department of Defence ASSURE program.

  10. 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

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

    NASA Astrophysics Data System (ADS)

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

    2015-05-01

    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.

  12. Power System Online Stability Assessment using Synchrophasor Data Mining 

    E-print Network

    Zheng, Ce

    2013-04-30

    , in particular the Decision Trees (DTs), for fast evaluation of power system oscillatory stability and voltage stability from synchrophasor measurements. A regression tree-based approach is proposed to predict the stability margins. Modal analysis...

  13. Sitting on stability balls: biomechanics evaluation in a workplace setting.

    PubMed

    Schult, Tamara M; Awosika, Ebi R; Schmunk, Sandra K; Hodgson, Michael J; Heymach, Bria L; Parker, Celestine Dent

    2013-01-01

    Use of a stability ball alone and stability ball chair were evaluated in the Veterans Health Administration as possible alternatives to incorporate with regular office chair use. The evaluation of stability ball use was conducted under the auspices of a work site health promotion program as a cross-over trial with participants rotating through use of the stability ball, stability ball chair, and regular office chair on a monthly basis for a total duration of 3 months. Rotations on regular office chairs served as the control. Three medical facilities participated. A total of 193 employees completed a baseline questionnaire; 159 completed at least one post-rotation questionnaire. Self-reported measures included perceived posture when sitting, perceptions of overall balance, energy levels, job performance, safety, and pain. Use was associated with improvements in perceived posture (p < 0.0001) and energy levels (p = 0.007) for stability ball users compared with the office chair control, and improvements in perceived posture (p < 0.0001) and overall balance (p = 0.05) for stability ball chair users compared with the control. Use of stability balls at work decreases the likelihood of reporting pain from regular office chair use from approximately 45% to 21%. Alternatively, a high number of participants reported pain with use of the stability ball alone and stability ball chair, 42% and 45%, respectively. The perceived risks and benefits of stability ball use should be weighed when incorporating use. PMID:23252582

  14. Stabilization of polymer electrolyte fuel cell voltage with reduced-order Lyapunov exponent feedback and corrective pressure perturbations

    NASA Astrophysics Data System (ADS)

    Burkholder, Michael B.; Litster, Shawn

    2015-02-01

    Polymer electrolyte fuel cell (PEFC) system efficiency can be decreased by instabilities resulting from the accumulation of water in the cathode as well as by excessive air delivery parasitic loads used to prevent liquid water accumulation. In this work, we present a new instability detection diagnostic tailored for the nonlinear and chaotic dynamics of PEFC operation with multi-phase flow in the gas channels. The instability statistic, the Lyapunov exponent of the reduced-order voltage return map, ?, is a measure of the exponential rate of divergence in the dynamic voltage signal measured from the fuel cell. A key advantage of this statistic for embedded control is that it is a self-referencing measure of the system stability for feedback and is not based on an a priori performance threshold. Our experiments demonstrate that the Lyapunov exponent statistic provides a warning typically 100 s in advance of significant power loss. Using this statistic as a control diagnostic, a new control scheme that detects PEFC instability in real time and mitigates it with pressure perturbations was applied experimentally to several fuel cell systems, including one that simulates stack operation. Our control scheme resulted in increased PEFC power, decreased cathode flooding leading to a lower parasitic load for air delivery, and stable PEFC performance.

  15. Quantitative Evaluation of Lightning Surge Range Voltage-time Characteristics in High Pressure SF6 Gas

    NASA Astrophysics Data System (ADS)

    Shinkai, Hiroyuki; Goshima, Hisashi; Yashima, Masafumi; Fujinami, Hideo

    Since gas-insulated switchgear (GIS) is subjected to very fast transient overvoltages such as lightning surges or disconnector switching surges. Therefore the sparkover voltage and time (V-t) characteristics of SF6 in a very short time range of less than 1?s are of great interest from the viewpoint of insulation design and coordination for a GIS. This paper describes the V-t characteristics of SF6 at a gas pressure of 0.5MPa using a steep-front square impulse voltage under a quasi-uniform field gap and presents a quantitative evaluation of the V-t characteristics for a nonstandard lightning impulse voltage. In the case of a square impulse, the V-t characteristics of positive polarity were observed to be almost flat over a long time range from 80ns to 10?s, and rose steeply over a short time range from 80ns down to 20ns. For negative polarity, the V-t characteristics exhibit a gentle rise from 200ns down to 40ns. In the estimation of V-t characteristics, the equal-area criterion parameters were quantitatively estimated using the square impulse. For a nonstandard lightning impulse, we found that the application of equal area criterion with these parameters for the non-oscillating impulse and oscillating impulse of up to 5.3MHz as a model of lightning surge and disconnector switching surge is possible.

  16. Stability evaluation of rotor/bearing system

    NASA Technical Reports Server (NTRS)

    Bently, D. E.; Muszynska, A.

    1982-01-01

    A stability study of rotor/bearing systems is presented. Even though it was limited to study of a fully lubricated bearing subject to oil whirl, and further limited to low eccentricity region for linearity and with only one type of lubricant, it can be seen that the perturbation methodology, together with the sorting of the impedance terms into direct and quadrature with respect to input force can be very useful to the general study of stability. Further, the concept of active feedback should assist to increase knowledge in rotor system stability. While there remains a large amount of study to be accomplished, perhaps some more tools are available to assist this field of analysis.

  17. An intelligent load shedding approach to enhance the voltage stability of a power system

    SciTech Connect

    Vadari, S.V.

    1991-01-01

    The objective of this dissertation is to perform an exhaustive study of the areas of load shedding and load management and recommend techniques for improvement (for the voltage problem). Two main accomplishments are presented. They are: (1) Expert Load Shedding (ELS), an intelligent operator's aid to help in load shedding is the result of the study of current load shedding practices, and intelligent methodologies. The method suggested in this document has been designed for implementation in an Energy management System (EMS) environment. A prototype of the ELS has been implemented in the Dispatcher Training Simulator (DTS) which simulates an EMS environment. Preliminary results of tests performed using the ELS on an enhanced version of the New-England 345-kV system has proved very promising. (2) Expert Load Management (ELM) is an expert system which has been used to provide load relief (in a distribution system) in an emergency mode. Load Management (LM) is an application in the Distribution Automation (DA) system which involves the process of controlling utility system loads by the remote control of individual customer loads. This expert system has been implemented in the EMS/DA environment and tested on the ODEC (Old Dominion Electric Cooperative) system. Preliminary results of the test performed have proved very promising. The main reason for the development of ELS and ELM are to enable the eventual linking of the two functions. It is the author's contention that a link between load shedding in the EMS and load management in the DA would be possible to obtain load relief without actually tripping feeders.

  18. Evaluation of higher distribution and/or utilization voltages. First interim report (December 1978): literature search and problem definition

    SciTech Connect

    Not Available

    1981-04-01

    A literature search has been conducted on the economics and technical problems associated with the use of higher voltages in both the primary distribution and secondary utilization systems. After a literature review and evaluation, an assessment of the state-of-the-art with regard to high voltage has been made and is presented for the primary and secondary distribution systems, end use elements, and economics and system analysis or optimization. An annotated bibliography is provided for each of the three categories. A comprehensive list of potential advantages and disadvantages of higher primary distribution and utilization voltages has also been prepared and is presented.

  19. 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 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

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

    SciTech Connect

    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 electropolished 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 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.

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

    SciTech Connect

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

    2015-07-15

    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 electropolished 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.

  2. ENVIRONMENTAL EVALUATION FOR UTILIZATION OF ASH IN SOIL STABILIZATION

    SciTech Connect

    David J. Hassett; Loreal V. Heebink

    2001-08-01

    The Minnesota Pollution Control Agency (MPCA) approved the use of coal ash in soil stabilization, indicating that environmental data needed to be generated. The overall project goal is to evaluate the potential for release of constituents into the environment from ash used in soil stabilization projects. Supporting objectives are: (1) To ensure sample integrity through implementation of a sample collection, preservation, and storage protocol to avoid analyte concentration or loss. (2) To evaluate the potential of each component (ash, soil, water) of the stabilized soil to contribute to environmental release of analytes of interest. (3) To use laboratory leaching methods to evaluate the potential for release of constituents to the environment. (4) To facilitate collection of and to evaluate samples from a field runoff demonstration effort. The results of this study indicated limited mobility of the coal combustion fly ash constituents in laboratory tests and the field runoff samples. The results presented support previous work showing little to negligible impact on water quality. This and past work indicates that soil stabilization is an environmentally beneficial CCB utilization application as encouraged by the U.S. Environmental Protection Agency. This project addressed the regulatory-driven environmental aspect of fly ash use for soil stabilization, but the demonstrated engineering performance and economic advantages also indicate that the use of CCBs in soil stabilization can and should become an accepted engineering option.

  3. Methods for determining optical power, for power-normalizing laser measurements, and for stabilizing power of lasers via compliance voltage sensing

    DOEpatents

    Taubman, Matthew S; Phillips, Mark C

    2015-04-07

    A method is disclosed for power normalization of spectroscopic signatures obtained from laser based chemical sensors that employs the compliance voltage across a quantum cascade laser device within an external cavity laser. The method obviates the need for a dedicated optical detector used specifically for power normalization purposes. A method is also disclosed that employs the compliance voltage developed across the laser device within an external cavity semiconductor laser to power-stabilize the laser mode of the semiconductor laser by adjusting drive current to the laser such that the output optical power from the external cavity semiconductor laser remains constant.

  4. Evaluation of stability of live attenuated camelpox vaccine stabilized with different stabilizers and reconstituted with various diluents.

    PubMed

    Prabhu, M; Bhanuprakash, V; Venkatesan, G; Yogisharadhya, R; Bora, D P; Balamurugan, V

    2014-05-01

    In this study, thermostability of a Vero cell attenuated live camelpox vaccine under conventional lyophilization conditions has been evaluated. Three stabilizers were used separately for freeze-drying the vaccine and the stability of the vaccine, both in freeze-dried and reconstituted forms at different temperatures was assessed. The study revealed that the camelpox vaccine lyophilized with TAA stabilizer found superior with a shelf life of 44 months, 227 days, 22 days and 20 days at 4, 25, 37 and 45 °C, respectively followed by LS stabilizer. In terms of half-life, TAA stabilizer proved better followed by LS and BUGS stabilizers at all temperatures except at 25 °C in which LS found relatively superior. Among the four diluents viz. 1x PBS (phosphate buffered saline, pH 7.4), 0.85% NaCl, distilled water and 1 M MgSO4, PBS was a better diluent followed by 0.85% NaCl. Both the diluents maintained the infectivity titer more than the minimum effective dose (3 log10TCID50 with a maximum titre of 6.53 log10TCID50 in both the diluents) for 60 h at 37 and 45 °C. However, 1 M MgSO4 found less suitable for camelpox vaccine dilution. The study indicates that the TAA and 1× PBS are the choice of stabilizer and diluent, respectively for camelpox vaccine. PMID:24657207

  5. Intrinsic Surface Stability in LiMn2-xNix04-s (x = 0.45, 0.5) High Voltage Spinel Materials for Lithium Ion Batteries

    SciTech Connect

    Carroll, Kyler J.; Yang, Ming-Che; Veith, G. M.; Dudney, N. J.; Meng, Ying Shirley

    2012-01-01

    This work reports the surface stability of the high voltage Li ion cathode LiMn{sub 2–x}Ni{sub x}O{sub 4–?} (x = 0.5, 0.45) by comparing thin film and powder composite electrodes after cycling using X-ray photoelectron spectroscopy. The thin film electrodes offer the ability to probe the surface of the material without the need of a conductive agent and polymer binder typically used in composite electrodes. The results suggest that neither oxidation of PF{sub 6} to POF{sub 3} nor the decomposition of ethylene carbonate or dimethylene carbonate occurs on the surface of the spinel material. These results confirm the enhanced cycling stability and rate capability associated with the high voltage spinel material and suggests that the SEI layer forms due to the reaction of electrochemically inactive components in composite electrodes with the electrolyte.

  6. 38 CFR 3.344 - Stabilization of disability evaluations.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 38 Pensions, Bonuses, and Veterans' Relief 1 2010-07-01 2010-07-01 false Stabilization of disability evaluations. 3.344 Section 3.344 Pensions, Bonuses, and Veterans' Relief DEPARTMENT OF VETERANS... essential that the entire record of examinations and the medical-industrial history be reviewed to...

  7. Evaluating the Performance of a Battery Using Temperature and Voltage Profiles and a Battery-Resistor Circuit Module

    ERIC Educational Resources Information Center

    Sawyer, Bryan; Ji, Michelle; Gordon, Michael J.; Suppes, Galen J.

    2010-01-01

    An experimental learning module has been developed to study the mass and energy balance involved with operation of an AA Alkaline battery under a load current. An extension of the module allows evaluation of laboratory-assembled batteries using granular anodic/cathodic materials. The system allows load resistance to be varied and measures voltage

  8. 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.

  9. Evaluation Methods of Contamination Flashover Voltage Performance of Cylindrical Type Semi-conducting Glaze Porcelain Insulators

    NASA Astrophysics Data System (ADS)

    Yamada, Kazuma; Hayashi, Akio; Saka, Chiharu; Sakanishi, Kenji; Matsuoka, Ryosuke; Ito, Susumu; Fujii, Osamu

    Higher contamination flashover voltage of a semi-conducting glaze (SG) insulator owes primarily to the drying effect by leakage current flowing in the glaze. Significant reduction in contamination flashover voltage was confirmed on a cylindrical SG insulator when fog density was increased from 0.5g/m3 to 13g/m3 in clean fog test. The effect of de-energized duration between trip-out and re-energization on the contamination flashover voltage of a cylindrical SG insulator under cold-wet switch-on conditions was investigated. As the de-energized duration becomes shorter, the flashover voltage of a cylindrical SG insulator becomes higher. Higher contamination design voltages may be adopted even under cold-wet switch-on conditions.

  10. Evaluation of slope stability with respect to snowpack spatial variability

    NASA Astrophysics Data System (ADS)

    Gaume, J.; Schweizer, J.; Herwijnen, A.; Chambon, G.; Reuter, B.; Eckert, N.; Naaim, M.

    2014-09-01

    The evaluation of avalanche release conditions constitutes a great challenge for risk assessment in mountainous areas. The spatial variability of snowpack properties has an important impact on snow slope stability and thus on avalanche formation, since it strongly influences failure initiation and crack propagation in weak snow layers. Hence, the determination of the link between these spatial variations and slope stability is very important, in particular, for avalanche public forecasting. In this study, a statistical-mechanical model of the slab-weak layer (WL) system relying on stochastic finite element simulations is used to investigate snowpack stability and avalanche release probability for spontaneously releasing avalanches. This model accounts, in particular, for the spatial variations of WL shear strength and stress redistribution by elasticity of the slab. We show how avalanche release probability can be computed from release depth distributions, which allows us to study the influence of WL spatial variations and slab properties on slope stability. The importance of smoothing effects by slab elasticity is verified and the crucial impact of spatial variation characteristics on the so-called knock-down effect on slope stability is revisited using this model. Finally, critical length values are computed from the simulations as a function of the various model parameters and are compared to field data obtained with propagation saw tests.

  11. Stability evaluation of Styrylpyrone derivative (SPD) incorporated products

    NASA Astrophysics Data System (ADS)

    Bahtiar, Adibah Ahamad; Nor, Norefrina Shafinaz Md.; Ibrahim, Nazlina

    2015-09-01

    Styrylpyrone derivative (SPD) from Goniothalamus umbrosus has been shown to have antiviral properties against Herpes Simplex virus type-1 (HSV-1). This study aimed to evaluate the purity of isolated SPD and stability of SPD-incorporated formulations. Pure SPD was isolated from dried roots of G. umbrosus as confirmed by GC-MS. Two types of SPD-incorporated products (ointment and gel) were produced. Both products showed stable physical properties after two months and retained the SPD content for one month.

  12. Using game theory to evaluate the stability of strategic forces

    SciTech Connect

    Reinhardt, G.C.; Squire, R.K.

    1982-02-01

    A game theory method for evaluating the stability of various strategic force deployments in a confrontation between two parties is described. To illustrate the method future US and Soviet ICBM forces are projected. Evaluation of the results indicates that the concept of deterrence can indeed be investigated in terms of a party's incentive or disincentive to initiate a nuclear exchange and that this measure can be quantitatively determined. We suggest that this allows us to structure strategic forces to preclude either side from calculating any advantage from initiating a nuclear exchange.

  13. 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

  14. 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.

  15. 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.

  16. Performance evaluation of wideband bio-impedance spectroscopy using constant voltage source and constant current source

    NASA Astrophysics Data System (ADS)

    Mohamadou, Youssoufa; In Oh, Tong; Wi, Hun; Sohal, Harsh; Farooq, Adnan; Woo, Eung Je; McEwan, Alistair Lee

    2012-10-01

    Current sources are widely used in bio-impedance spectroscopy (BIS) measurement systems to maximize current injection for increased signal to noise while keeping within medical safety specifications. High-performance current sources based on the Howland current pump with optimized impedance converters are able to minimize stray capacitance of the cables and setup. This approach is limited at high frequencies primarily due to the deteriorated output impedance of the constant current source when situated in a real measurement system. For this reason, voltage sources have been suggested, but they require a current sensing resistor, and the SNR reduces at low impedance loads due to the lower current required to maintain constant voltage. In this paper, we compare the performance of a current source-based BIS and a voltage source-based BIS, which use common components. The current source BIS is based on a Howland current pump and generalized impedance converters to maintain a high output impedance of more than 1?M? at 2?MHz. The voltage source BIS is based on voltage division between an internal current sensing resistor (Rs) and an external sample. To maintain high SNR, Rs is varied so that the source voltage is divided more or less equally. In order to calibrate the systems, we measured the transfer function of the BIS systems with several known resistor and capacitor loads. From this we may estimate the resistance and capacitance of biological tissues using the least-squares method to minimize error between the measured transimpedance excluding the system transfer function and that from an impedance model. When tested on realistic loads including discrete resistors and capacitors, and saline and agar phantoms, the voltage source-based BIS system had a wider bandwidth of 10 Hz to 2.2 MHz with less than 1% deviation from the expected spectra compared to more than 10% with the current source. The voltage source also showed an SNR of at least 60 dB up to 2.2 MHz in comparison to the current source-based BIS system where the SNR drops below 40 dB for frequencies greater than 1 MHz.

  17. Robust Voltage Stabilization in an Isolated Wind-Diesel Power System using PSO based-Fixed Structure H? Loop Shaping Control

    NASA Astrophysics Data System (ADS)

    Vachirasricirikul, Sitthidet; Ngamroo, Issarachai; Kaitwanidvilai, Somyot

    It is well known that the power system controller designed by H? control is complicated, high order and impractical. In power system applications, practical structures such as proportional integral derivative (PID) etc., are widely used, because of their simple structure, less number of tuning parameters and low-order. However, tuning of controller parameters to achieve a good performance and robustness is based on designer's experiences. To overcome this problem, this paper proposes a fixed structure robust H? loop shaping control to design Static Var Compensator (SVC) and Automatic Voltage Regulator (AVR) for robust stabilization of voltage fluctuation in an isolated wind-diesel hybrid power system. The structure of the robust controller of SVC and AVR is specified by a PID controller. In the system modeling, a normalized coprime factorization is applied to represent possible unstructured uncertainties in the power system such as variation of system parameters, generating and loading conditions etc. Based on the H? loop shaping, the performance and robust stability conditions are formulated as the optimization problem. The particle swarm optimization is applied to solve for PID control parameters of SVC and AVR simultaneously. Simulation studies confirm the control effect and robustness of the proposed control.

  18. Development and Evaluation of Transferrin-Stabilized Paclitaxel Nanocrystal Formulation

    PubMed Central

    Lu, Ying; Wang, Zhao-hui; Li, Tonglei; McNally, Helen; Park, Kinam; Sturek, Michael

    2014-01-01

    The aim of the present study was to prepare and evaluate a paclitaxel nanocrystal-based formulation stabilized by serum protein transferrin in a non-covalent manner. The pure paclitaxel nanocrystals were first prepared using an antisolvent precipitation method augmented by sonication. The serum protein transferrin was selected for use after evaluating the stabilizing effect of several serum proteins including albumin and immunoglobulin G. The formulation contained approximately 55~60% drug and was stable for at least 3 months at 4 °C. In vivo antitumor efficacy studies using mice inoculated with KB cells demonstrate significantly higher tumor inhibition rate of 45.1% for paclitaxel-transferrin formulation compared to 28.8% for paclitaxel nanosuspension treatment alone. Interestingly, the Taxol® formulation showed higher antitumor activity than the paclitaxel-transferrin formulation, achieving a 93.3% tumor inhibition rate 12 days post initial dosing. However, the paclitaxel-transferrin formulation showed a lower level of toxicity, which is indicated by steady increase in body weight of mice over the treatment period. In comparison, treatment with Taxol® resulted in toxicity issues as body weight decreased. These results suggest the potential benefit of using a serum protein in a non-covalent manner in conjunction with paclitaxel nanocrystals as a promising drug delivery model for anticancer therapy. PMID:24378441

  19. 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

  20. 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.

  1. Evaluation of higher distribution and/or utilization voltages. Fourth interim report (August 1980): assessment of optimum distribution configuration

    SciTech Connect

    Not Available

    1981-04-01

    This interim report provides documentation on the fourth task, Assessment of Optimum Distribution Configuration, 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 computer model for assessment of life cycle costs for the distribution and utilization systems, the development of an optimization algorithm to enable distribution system configuration optimization and a net energy analysis to determine potential net energy savings. Input data for this task derive from Task 3. The major output of this task is a documented computer code.

  2. 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

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

    PubMed Central

    Slowik, Daria; Henderson, Richard

    2015-01-01

    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

  4. Preliminary safety evaluation for the plutonium stabilization and packaging system

    SciTech Connect

    Shapley, J.E., Fluor Daniel Hanford

    1997-03-14

    This Preliminary Safety Evaluation (PSE) describes and analyzes the installation and operation of the Plutonium Stabilization and Packaging System (SPS) at the Plutonium Finishing Plant (PFP). The SPS is a combination of components required to expedite the safe and timely storage of Plutonium (Pu) oxide. The SPS program will receive site Pu packages, process the Pu for storage, package the Pu into metallic containers, and safely store the containers in a specially modified storage vault. The location of the SPS will be in the 2736- ZB building and the storage vaults will be in the 2736-Z building of the PFP, as shown in Figure 1-1. The SPS will produce storage canisters that are larger than those currently used for Pu storage at the PFP. Therefore, the existing storage areas within the PFP secure vaults will require modification. Other modifications will be performed on the 2736-ZB building complex to facilitate the installation and operation of the SPS.

  5. 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; Hefei National Laboratory for Physical Sciences at Microscale, University of Science and Technology of China, Hefei, Anhui 230026 ; Hou, Yubin

    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.

  6. straightjacket is required for the synaptic stabilization of cacophony, a voltage-gated calcium channel ?1 subunit

    PubMed Central

    Ly, Cindy V.; Yao, Chi-Kuang; Verstreken, Patrik; Ohyama, Tomoko; Bellen, Hugo J.

    2008-01-01

    In a screen to identify genes involved in synaptic function, we isolated mutations in Drosophila melanogaster straightjacket (stj), an ?2? subunit of the voltage-gated calcium channel. stj mutant photoreceptors develop normal synaptic connections but display reduced “on–off” transients in electroretinogram recordings, indicating a failure to evoke postsynaptic responses and, thus, a defect in neurotransmission. stj is expressed in neurons but excluded from glia. Mutants exhibit endogenous seizure-like activity, indicating altered neuronal excitability. However, at the synaptic level, stj larval neuromuscular junctions exhibit approximately fourfold reduction in synaptic release compared with controls stemming from a reduced release probability at these synapses. These defects likely stem from destabilization of Cacophony (Cac), the primary presynaptic ?1 subunit in D. melanogaster. Interestingly, neuronal overexpression of cac partially rescues the viability and physiological defects in stj mutants, indicating a role for the ?2? Ca2+ channel subunit in mediating the proper localization of an ?1 subunit at synapses. PMID:18391075

  7. 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.

  8. Evaluation of tunnel stability using integrated geophysical methods

    NASA Astrophysics Data System (ADS)

    Cardarelli, E.; Marrone, C.; Orlando, L.

    2003-02-01

    An integrated interpretation was made of data, from ground penetrating radar (GPR), seismic refraction and seismic transmission tomography, collected inside the catchment tunnels of a potable water source in central Italy. Rock fracturing and obsolescence of the concrete lining in a tunnel led a landslide that caused structural instability in the catchment work structures. To assess the stability of the rock close to the landslide, geophysical surveys were preferred to boreholes and geotechnical tests in order to avoid water pollution and the risk of further landslides. The interpretation of integrated data from seismic tomography and 200 MHz antenna GPR resulted in an evaluation of some of the elastic characteristics and the detection of discontinuities in the rock. Note also that an analysis of the back-scattered energy was required for the GPR data interpretation. The integration of seismic refraction data and 450 MHz antenna allowed us to identify the loosened zone around the tunnel and the extent of the mass involved in the cave-in, while GPR data from 225 MHz were used to evaluate the quality of contact between concrete lining and massive rock.

  9. Demonstration and Field Evaluation of Streambank Stabilization with Submerged Vanes

    USGS Publications Warehouse

    Whitman, H.; Hoopes, J.; Poggi, D.; Fitzpatrick, F.; Walz, K.

    2001-01-01

    The effectiveness of submerged vanes for reducing bank erosion and improving aquatic habitat is being evaluated at a site on North Fish Creek, a Lake Superior tributary. Increased runoff from agricultural areas with clayey soils has increased flood magnitudes and the erosion potential/transport capacity of the stream. Most of the creek's sediment load originates from the erosion of 17 large bluffs. This creek contains important recreational fisheries that are potentially limited by the loss of aquatic habitat from deposition of sediment on spawning beds. Submerged vanes are a cost effective and environmentally less intrusive alternative to traditional structural stabilization measures. Submerged vanes protrude from a channel bed, are oriented at an angle to the local velocity, and are distributed along a portion of channel. They induce a transverse force and torque on the flow along with longitudinal vortexes that alter the cross sectional shape and alignment of the channel. Submerged vanes were installed at a bluff/bend site in summer and fall 2000. The number, size, and layout of the vanes were based upon the channel morphology under estimated bankfull conditions. The effectiveness of the vanes will be evaluated by comparing surveys of the bluff face, streamflow, and channel conditions for several years after installation of the submerged vanes with surveys before and immediately after their installation.

  10. Passive protection devices for high-voltage equipment: Design procedures and performance evaluation

    SciTech Connect

    Serino, G.; Bonacina, G.; Bettinali, F.

    1995-12-31

    A 420 kV High-Voltage Alternating Current Circuit-Breaker, a typical element of an open-air electrical substation, is considered. Experimental tests carried out on such a piece of equipment by ISMES, under ENEL support, clearly pointed out its inability to withstand the seismic qualification level of highest severity indicated by the standards. The design of a seismic isolation system for the switch-gear composed of spring units and dampers is developed in this paper, and the dynamic earthquake response of the isolated circuit-breaker is compared numerically to the one obtained without the seismic protection system. The remarkable reduction of stresses in the porcelain insulators are shown, evidencing that this occurs to the detriment of a certain increment of displacements at the top of the apparatus.

  11. Modelling of illuminated current–voltage characteristics to evaluate leakage currents in long wavelength infrared mercury cadmium telluride photovoltaic detectors

    SciTech Connect

    Gopal, Vishnu E-mail: wdhu@mail.sitp.ac.cn; Qiu, WeiCheng; Hu, Weida E-mail: wdhu@mail.sitp.ac.cn

    2014-11-14

    The current–voltage characteristics of long wavelength mercury cadmium telluride infrared detectors have been studied using a recently suggested method for modelling of illuminated photovoltaic detectors. Diodes fabricated on in-house grown arsenic and vacancy doped epitaxial layers were evaluated for their leakage currents. The thermal diffusion, generation–recombination (g-r), and ohmic currents were found as principal components of diode current besides a component of photocurrent due to illumination. In addition, both types of diodes exhibited an excess current component whose growth with the applied bias voltage did not match the expected growth of trap-assisted-tunnelling current. Instead, it was found to be the best described by an exponential function of the type, I{sub excess}?=?I{sub r0}?+?K{sub 1} exp (K{sub 2} V), where I{sub r0}, K{sub 1}, and K{sub 2} are fitting parameters and V is the applied bias voltage. A study of the temperature dependence of the diode current components and the excess current provided the useful clues about the source of origin of excess current. It was found that the excess current in diodes fabricated on arsenic doped epitaxial layers has its origin in the source of ohmic shunt currents. Whereas, the source of excess current in diodes fabricated on vacancy doped epitaxial layers appeared to be the avalanche multiplication of photocurrent. The difference in the behaviour of two types of diodes has been attributed to the difference in the quality of epitaxial layers.

  12. EVALUATION OF SOLIDIFICATION/STABILIZATION AS A BEST DEMONSTRATED AVAILABLE TECHNOLOGY FOR CONTAMINATED SOILS

    EPA Science Inventory

    This project involved the evaluation of solidification/stabilization technology as a BDAT for contaminated soil. Three binding agents were used on four different synthetically contaminated soils. Performance evaluation data included unconfined compressive strength (UCS) and the T...

  13. 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

  14. 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.

  15. Evaluation of a Programmable Voltage-Controlled MEMS Oscillator, Type SiT3701, Over a Wide Temperature Range

    NASA Technical Reports Server (NTRS)

    Patterson, Richard; Hammoud, Ahmad

    2009-01-01

    Semiconductor chips based on MEMS (Micro-Electro-Mechanical Systems) technology, such as sensors, transducers, and actuators, are becoming widely used in today s electronics due to their high performance, low power consumption, tolerance to shock and vibration, and immunity to electro-static discharge. In addition, the MEMS fabrication process allows for the miniaturization of individual chips as well as the integration of various electronic circuits into one module, such as system-on-a-chip. These measures would simplify overall system design, reduce parts count and interface, improve reliability, and reduce cost; and they would meet requirements of systems destined for use in space exploration missions. In this work, the performance of a recently-developed MEMS voltage-controlled oscillator was evaluated under a wide temperature range. Operation of this new commercial-off-the-shelf (COTS) device was also assessed under thermal cycling to address some operational conditions of the space environment

  16. 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.

  17. 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.

  18. SiNWs-based electrochemical double layer micro-supercapacitors with wide voltage window (4 V) and long cycling stability using a protic ionic liquid electrolyte

    NASA Astrophysics Data System (ADS)

    Aradilla, David; Gentile, Pascal; Ruiz, Vanesa; Gómez-Romero, Pedro; Wimberg, Jan; Iliev, Boyan; Schubert, Thomas J. S.; Sadki, Saïd; Bidan, Gérard

    2015-03-01

    The present work reports the use and application of a novel protic ionic liquid (triethylammonium bis(trifluoromethylsulfonyl)imide; NEt3H TFSI) as an electrolyte for symmetric planar micro-supercapacitors based on silicon nanowire electrodes. The excellent performance of the device has been successfully demonstrated using cyclic voltammetry, galvanostatic charge-discharge cycles and electrochemical impedance spectroscopy. The electrochemical characterization of this system exhibits a wide operative voltage of 4 V as well as an outstanding long cycling stability after millions of galvanostatic cycles at a high current density of 2 mA cm-2. In addition, the electrochemical double layer micro-supercapacitor was able to deliver a high power density of 4 mW cm-2 in a very short time pulses (a few ms). Our results could be of interest to develop prospective on-chip micro-supercapacitors using protic ionic liquids as electrolytes with high performance in terms of power and energy densities. Invited talk at the 2nd International Workshop on Nano Materials for Energy Conversion NMEC-2, 17-20 November, 2014, Ho Chi Minh City, Vietnam.

  19. Evaluation of an alternative bituminous material as a soil stabilizer 

    E-print Network

    Kim, Yong-Rak

    1999-01-01

    Asphalt cements, cutback asphalts, and emulsified asphalts are used as bituminous stabilizing agents in the pavement systems. The emulsified asphalts are increasingly used in lieu of cutback asphalts because of environmental regulations and safety...

  20. Safety evaluation of interim stabilization of non-stabilized single-shell watch list tanks

    SciTech Connect

    Stahl, S.M.

    1994-12-30

    The report provides a summation of the status of safety issues associated with interim stabilization of Watch List SSTs (organic, ferrocyanide, and flammable gas), as extracted from recent safety analyses, including the Tank Farms Accelerated Safety Analysis efforts.

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

    EPA Science Inventory

    This Technolgy Evaluation Report evaluates the solidification/stabilization process of Silicate Technology Corporation (STC) for the on-site treatment of contaminated soil The STC immobilization technology uses a proprietary product (FMS Silicate) to chemically stabilize and ...

  2. Dynamic characteristics of noncontacting seal and evaluation of its effect on stability of rotor system

    NASA Astrophysics Data System (ADS)

    Iwatsubo, Takuzo

    Recent investigations on dynamic characteristics of the labyrinth seal and the pump seal are reviewed, and contributions of each element to stability of the rotor are illustrated for both seals. A method to evaluate the contribution of each element to the stability of a machine is presented. It is shown how to synthesize the rotor system by using the contribution of each element to stability.

  3. 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.

  4. Note: Effective measurement of retained Ic in evaluating electromechanical properties of high temperature superconductor tapes by the voltage tap clipping technique

    NASA Astrophysics Data System (ADS)

    Dedicatoria, Marlon J.; Bautista, Zhierwinjay; Shin, Hyung-Seop; Sim, Kideok

    2015-08-01

    In this note, the effectiveness of voltage tap clipping technique was assessed in evaluating the electromechanical properties of high temperature superconductor (HTS) tapes in the aspect of practical device applications. In the four-probe transport Ic measurement, instead of directly soldering the voltage lead wires onto the HTS samples, they were tapped to the sample by either just clipping or soldering them to the clips. This technique facilitated the simultaneous and repeated retained Ic measurement test for multiple samples. Finally, the critical double bending diameter of HTS tapes and the electrical properties of jointed and striated coated conductor tapes could be easily determined.

  5. 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 ...

  6. Evaluation of the stability of gas hydrates in Northern Alaska

    USGS Publications Warehouse

    Kamath, A.; Godbole, S.P.; Ostermann, R.D.; Collett, T.S.

    1987-01-01

    The factors which control the distribution of in situ gas hydrate deposits in colder regions such as Northern Alaska include; mean annual surface temperatures (MAST), geothermal gradients above and below the base of permafrost, subsurface pressures, gas composition, pore-fluid salinity and the soil condition. Currently existing data on the above parameters for the forty-six wells located in Northern Alaska were critically examined and used in calculations of depths and thicknesses of gas hydrate stability zones. To illustrate the effect of gas hydrate stability zones, calculations were done for a variable gas composition using the thermodynamic model of Holder and John (1982). The hydrostatic pressure gradient of 9.84 kPa/m (0.435 lbf/in2ft), the salinity of 10 parts per thousand (ppt) and the coarse-grained soil conditions were assumed. An error analysis was performed for the above parameters and the effect of these parameters on hydrate stability zone calculations were determined. After projecting the hydrate stability zones for the forty-six wells, well logs were used to identify and to obtain values for the depth and thickness of hydrate zones. Of the forty-six wells, only ten wells showed definite evidence of the presence of gas hydrates. ?? 1987.

  7. Evaluation of HAN-TEAN Stabilizers using Microcalorimetry

    NASA Technical Reports Server (NTRS)

    Hornung, Steven D.; Davis, Dennis D.; Chang, Craig H.; Baker, David L.

    1997-01-01

    HAN-TEAN (hydroxylammonium nitrate - triethanolammonium nitrate - in water) is being considered for various propellant applications. This propellant has advantages in terms of insensitivity to impact and fire, low vapor pressure and environmentally benign reaction products. One office concerns with HAN-TEAN is its stability and shelf-life, especially when contaminated with trace metals. Stabilizer systems, consisting of anti-oxidants and/or chealating agents were investigated for their ability to control the decomposition of HAN-TEAN. Isothermal microcalorimetry, an ultrasensitive heat measurement technique, was used to monitor the decomposition of HANTEAN at near ambient temperatures. Isothermal microcalorimetry measures the heat flow from a reaction vessel into a surrounding heat sink. Microcalorimetry is approximately 1,000 times more sensitive than accelerating rate calorimetry (ARC) or differential scanning calorimetry (DSC) for measuring heat flow. Samples of HAN-TEAN containing the stabilizers were spiked with 50 ppm iron and the heat evolution monitored for a period of at least 30 days. Ten stabilizer combinations were tested and the rates of HAN-TEAN decomposition were lowered by 74 to 95 percent in the presence of iron.

  8. Toxicological evaluation of the chemical oxidation methods for landfill stabilization.

    PubMed

    Cho, Eun-ah; Tameda, Kazuo; Hanashima, Masataka; Yamada, Tatsuyoshi; Higuchi, Sotaro

    2009-03-01

    As the stabilization criteria for landfill sites, only chemical criteria for the leachate discharges from the landfill sites have been used in Japan and many other countries. Recently, chemical oxidation has been developed as a method for the early-stabilization of landfills. However, by-products that are difficult to detect by chemical analysis can be produced by this method. Therefore, toxicity tests are useful tools for detecting the changes of leachate quality after application of this method. The heat source in the A landfill was analyzed by organic position inquiry technology, and ozone-treated leachate was sprayed back to the heat source in the landfill. Toxicity changes of the leachate after the spray were monitored using Microtoxtrade mark, ToxScreen-II, and DaphTox tests. The hardly-degradable organic matter was efficiently removed and toxicities of the leachate in the heat source decreased after the application. These toxicity results were significantly related to chemical oxygen demand (COD) changes. Thus, it was concluded that the toxicity tests were effective for monitoring the leachate quality after applying the chemical oxidation method for landfill stabilization, and its incorporation to establish the criteria for early-stabilization of landfill sites needs to be considered. PMID:18838260

  9. Intrinsic Surface Stability in LiMn2-xNixO4-d (x=0.45, 0.5) High Volt-age Spinel Materials for Lithium Ion Batteries

    SciTech Connect

    Carroll, Kyler J; Yang, Ming-Che; Veith, Gabriel M; Dudney, Nancy J; Meng, Ying Shirley

    2012-01-01

    This work reports the surface stability of the high voltage Li ion cathode LiMn2-xNixO4- (x= 0.5, 0.45) by comparing thin film and powder composite electrodes after cycling using X-ray photoelectron spectroscopy. The thin film electrodes offer the ability to probe the surface of the material without the need of a conductive agent and polymer binder typically used in composite electrodes. The results suggest that neither oxidation of PF6 to POF5 nor the decomposition of ethylene carbonate or dimethylene carbonate occurs on the surface of the spinel material. These results confirm the enhanced cycling stability and rate capability associated with the high voltage spinel material and suggests that the SEI layer forms due to the reaction of electrochemically inactive components in composite electrodes with the electrolyte.

  10. A Polybasic Plasma Membrane Binding Motif in the I-II Linker Stabilizes Voltage-gated CaV1.2 Calcium Channel Function*

    PubMed Central

    Kaur, Gurjot; Pinggera, Alexandra; Ortner, Nadine J.; Lieb, Andreas; Sinnegger-Brauns, Martina J.; Yarov-Yarovoy, Vladimir; Obermair, Gerald J.; Flucher, Bernhard E.; Striessnig, Jörg

    2015-01-01

    L-type voltage-gated Ca2+ channels (LTCCs) regulate many physiological functions like muscle contraction, hormone secretion, gene expression, and neuronal excitability. Their activity is strictly controlled by various molecular mechanisms. The pore-forming ?1-subunit comprises four repeated domains (I–IV), each connected via an intracellular linker. Here we identified a polybasic plasma membrane binding motif, consisting of four arginines, within the I-II linker of all LTCCs. The primary structure of this motif is similar to polybasic clusters known to interact with polyphosphoinositides identified in other ion channels. We used de novo molecular modeling to predict the conformation of this polybasic motif, immunofluorescence microscopy and live cell imaging to investigate the interaction with the plasma membrane, and electrophysiology to study its role for Cav1.2 channel function. According to our models, this polybasic motif of the I-II linker forms a straight ?-helix, with the positive charges facing the lipid phosphates of the inner leaflet of the plasma membrane. Membrane binding of the I-II linker could be reversed after phospholipase C activation, causing polyphosphoinositide breakdown, and was accelerated by elevated intracellular Ca2+ levels. This indicates the involvement of negatively charged phospholipids in the plasma membrane targeting of the linker. Neutralization of four arginine residues eliminated plasma membrane binding. Patch clamp recordings revealed facilitated opening of Cav1.2 channels containing these mutations, weaker inhibition by phospholipase C activation, and reduced expression of channels (as quantified by ON-gating charge) at the plasma membrane. Our data provide new evidence for a membrane binding motif within the I-II linker of LTCC ?1-subunits essential for stabilizing normal Ca2+ channel function. PMID:26100638

  11. 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.

  12. Recommendations for the evaluation of specimen stability for flow cytometric testing during drug development.

    PubMed

    Brown, Lynette; Green, Cherie L; Jones, Nicholas; Stewart, Jennifer J; Fraser, Stephanie; Howell, Kathy; Xu, Yuanxin; Hill, Carla G; Wiwi, Christopher A; White, Wendy I; O'Brien, Peter J; Litwin, Virginia

    2015-03-01

    The objective of this manuscript is to present an approach for evaluating specimen stability for flow cytometric methods used during drug development. While this approach specifically addresses stability assessment for assays to be used in clinical trials with centralized testing facilities, the concepts can be applied to any stability assessment for flow cytometric methods. The proposed approach is implemented during assay development and optimization, and includes suggestions for designing a stability assessment plan, data evaluation and acceptance criteria. Given that no single solution will be applicable in all scenarios, this manuscript offers the reader a roadmap for stability assessment and is intended to guide the investigator during both the method development phase and in the experimental design of the validation plan. PMID:25662815

  13. Evaluation of constraint stabilization procedures for multibody dynamical systems

    NASA Technical Reports Server (NTRS)

    Park, K. C.; Chiou, J. C.

    1987-01-01

    Comparative numerical studies of four constraint treatment techniques for the simulation of general multibody dynamic systems are presented, and results are presented for the example of a classical crank mechanism and for a simplified version of the seven-link manipulator deployment problem. The staggered stabilization technique (Park, 1986) is found to yield improved accuracy and robustness over Baumgarte's (1972) technique, the singular decomposition technique (Walton and Steeves, 1969), and the penalty technique (Lotstedt, 1979). Furthermore, the staggered stabilization technique offers software modularity, and the only data each solution module needs to exchange with the other is a set of vectors plus a common module to generate the gradient matrix of the constraints, B.

  14. Evaluating the cement stabilization of arsenic-bearing iron wastes from drinking water treatment.

    PubMed

    Clancy, Tara M; Snyder, Kathryn V; Reddy, Raghav; Lanzirotti, Antonio; Amrose, Susan E; Raskin, Lutgarde; Hayes, Kim F

    2015-12-30

    Cement stabilization of arsenic-bearing wastes is recommended to limit arsenic release from wastes following disposal. Such stabilization has been demonstrated to reduce the arsenic concentration in the Toxicity Characteristic Leaching Procedure (TCLP), which regulates landfill disposal of arsenic waste. However, few studies have evaluated leaching from actual wastes under conditions similar to ultimate disposal environments. In this study, land disposal in areas where flooding is likely was simulated to test arsenic release from cement stabilized arsenic-bearing iron oxide wastes. After 406 days submersed in chemically simulated rainwater, <0.4% of total arsenic was leached, which was comparable to the amount leached during the TCLP (<0.3%). Short-term (18h) modified TCLP tests (pH 3-12) found that cement stabilization lowered arsenic leaching at high pH, but increased leaching at pH<4.2 compared to non-stabilized wastes. Presenting the first characterization of cement stabilized waste using ?XRF, these results revealed the majority of arsenic in cement stabilized waste remained associated with iron. This distribution of arsenic differed from previous observations of calcium-arsenic solid phases when arsenic salts were stabilized with cement, illustrating that the initial waste form influences the stabilized form. Overall, cement stabilization is effective for arsenic-bearing wastes when acidic conditions can be avoided. PMID:26247378

  15. Lithium-cyclo-difluoromethane-1,1-bis(sulfonyl)imide as a stabilizing electrolyte additive for improved high voltage applications in lithium-ion batteries.

    PubMed

    Murmann, Patrick; Streipert, Benjamin; Kloepsch, Richard; Ignatiev, Nikolai; Sartori, Peter; Winter, Martin; Cekic-Laskovic, Isidora

    2015-04-14

    Lithium-cyclo-difluoromethane-1,1-bis(sulfonyl)imide (LiDMSI) was evaluated as an electrolyte additive in lithium-ion batteries for improved high voltage applications. Cycling the cathode at high potentials leads to the electrochemical oxidation of the salt to form a cathode electrolyte interphase (CEI) layer on the cathode surface. With the addition of 2 wt% of LiDMSI to the 1 M LiPF6 in 1?:?1 (by wt) EC?:?DEC electrolyte, the capacity retention and the Coulombic efficiency in LiNi1/3Co1/3Mn1/3O2/Li-half-cells as well as in LiNi1/3Co1/3Mn1/3O2/graphite-full-cells were improved. The cycling results point out the less over-potential and resistance at the cathode/electrolyte interface. These improvements are studied by SEM, EIS and XPS techniques. PMID:25760031

  16. Evaluation of the Cell Voltage of Electrolytic HI Concentration for Thermochemical Water-Splitting Iodine-Sulfur Process

    SciTech Connect

    Tanaka, Nobuyuki; Yoshida, Mitsunori; Okuda, Hiroyuki; Sato, Hiroyuki; Kubo, Shinji; Onuki, Kaoru

    2007-07-01

    Breakdown of the cell voltage in the electro-dialysis process for concentrating HIx solution (HI-H{sub 2}O-I{sub 2} mixture) was preliminarily examined in an effort to clarify the optimal operation condition as well as to optimize the cell design for the application to the thermochemical water-splitting IS process for large-scale hydrogen production. Basic data such as electric resistance of HIx solution, overvoltage of the iodine-iodide ion redox reaction at graphite electrode, and the membrane voltage drop, were measured using HIx solution with composition of interest. Also, a methodology for estimating the cell voltage was discussed. The calculated cell voltage agreed well with the experimental one indicating the validity of the procedure adopted. (authors)

  17. Evaluation of first 10-kV optical ETO thyristor operating without any low-voltage control bias

    E-print Network

    Mazumder, Sudip K.

    and ambient temperatures. To facilitate these extreme applications, SiC devices have been used, and have been to drive standard power MOSFETs and IGBTs [7],[8] but required a second low voltage bias. The outlined all

  18. Evaluation of degradation kinetics and physicochemical stability of tenofovir.

    PubMed

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

    2015-03-01

    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 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 solutions. 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

  19. 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...

  20. 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...

  1. High Voltage TAL Performance

    NASA Technical Reports Server (NTRS)

    Jacobson, David T.; Jankovsky, Robert S.; Rawlin, Vincent K.; Manzella, David H.

    2001-01-01

    The performance of a two-stage, anode layer Hall thruster was evaluated. Experiments were conducted in single and two-stage configurations. In single-stage configuration, the thruster was operated with discharge voltages ranging from 300 to 1700 V. Discharge specific impulses ranged from 1630 to 4140 sec. Thruster investigations were conducted with input power ranging from 1 to 8.7 kW, corresponding to power throttling of nearly 9: 1. An extensive two-stage performance map was generated. Data taken with total voltage (sum of discharge and accelerating voltage) constant revealed a decrease in thruster efficiency as the discharge voltage was increased. Anode specific impulse values were comparable in the single and two-stage configurations showing no strong advantage for two-stage operation.

  2. Myopia Stabilization and Associated Factors Among Participants in the Correction of Myopia Evaluation Trial (COMET)

    PubMed Central

    2013-01-01

    Purpose. To use the Gompertz function to estimate the age and the amount of myopia at stabilization and to evaluate associated factors in the Correction of Myopia Evaluation Trial (COMET) cohort, a large ethnically diverse group of myopic children. Methods. The COMET enrolled 469 ethnically diverse children aged 6 to younger than 12 years with spherical equivalent refraction between ?1.25 and ?4.50 diopters (D). Noncycloplegic refraction was measured semiannually for 4 years and annually thereafter. Right eye data were fit to individual Gompertz functions in participants with at least 6 years of follow-up and at least seven refraction measurements over 11 years. Function parameters were estimated using a nonlinear least squares procedure. Associated factors were evaluated using linear regression. Results. In total, 426 participants (91%) had valid Gompertz curve fits. The mean (SD) age at myopia stabilization was 15.61 (4.17) years, and the mean (SD) amount of myopia at stabilization was ?4.87 (2.01) D. Ethnicity (P < 0.0001) but not sex or the number of myopic parents was associated with the age at stabilization. Ethnicity (P = 0.02) and the number of myopic parents (P = 0.01) but not sex were associated with myopia magnitude at stabilization. At stabilization, African Americans were youngest (mean age, 13.82 years) and had the least myopia (mean, ?4.36 D). Participants with two versus no myopic parents had approximately 1.00 D more myopia at stabilization. The age and the amount of myopia at stabilization were correlated (r = ?0.60, P < 0.0001). Conclusions. The Gompertz function provides estimates of the age and the amount of myopia at stabilization in an ethnically diverse cohort. These findings should provide guidance on the time course of myopia and on decisions regarding the type and timing of interventions. PMID:24159085

  3. Spillover in the Academy: Marriage Stability and Faculty Evaluations.

    ERIC Educational Resources Information Center

    Ludlow, Larry H.; Alvarez-Salvat, Rose M.

    2001-01-01

    Studied the spillover between family and work by examining the link between marital status and work performance across marriage, divorce, and remarriage. A polynomial regression model was fit to the data from 78 evaluations of an individual professor, and a cubic curve through the 3 periods was statistically significant. (SLD)

  4. Extended performance solar electric propulsion thrust system study. Volume 5. Capacitor-diode voltage multiplier: Technology evaluation

    NASA Technical Reports Server (NTRS)

    Martinelli, R. M.

    1977-01-01

    A 1-kW capacitor-diode voltage multiplier (CDVM) was designed, fabricated and tested to demonstrate the power of feasibility of high power CDVM's and to verify the analytical techniques that had been used to predict the performance characteristics of a 6-kw CDVM. High efficiency (96.2%), a low ratio of component weight to power (0.55 kg/kW), and low output ripple voltage (less than 1%, peak to peak) were obtained during the operation of a 1-kW CDVM various input line, load current, and load fault conditions.

  5. Enhanced analogue front-end for the measurement of the high state of wide-band voltage pulses with 87 dB common-mode rejection ratio and ±0.65 ppm 1-day offset stability

    NASA Astrophysics Data System (ADS)

    Arpaia, Pasquale; Baccigalupi, Carlo; Martino, Michele

    2015-09-01

    An improved analogue front-end for measuring the high state of trapezoidal voltage pulses with transition duration of 3 ?s is presented. A new measurement system, composed by a front-end and the state-of-the-art acquisition board NI PXI-5922, has been realized with improved Common Mode Rejection Ratio (CMRR) of more than 87 dB at DC and 3-sigma stability of ±0.65 ppm over 1 day. After highlighting the main design enhancements with respect to state-of-the-art solutions, the CMRR measurement is reported. The output drift due to temperature and humidity is assessed to be negligible. Finally, the worst-case repeatability is measured both with shorted-to-ground inputs and with an applied common-mode voltage of 10 V, which represents the nominal working condition.

  6. Enhanced analogue front-end for the measurement of the high state of wide-band voltage pulses with 87 dB common-mode rejection ratio and ±0.65 ppm 1-day offset stability.

    PubMed

    Arpaia, Pasquale; Baccigalupi, Carlo; Martino, Michele

    2015-09-01

    An improved analogue front-end for measuring the high state of trapezoidal voltage pulses with transition duration of 3 ?s is presented. A new measurement system, composed by a front-end and the state-of-the-art acquisition board NI PXI-5922, has been realized with improved Common Mode Rejection Ratio (CMRR) of more than 87 dB at DC and 3-sigma stability of ±0.65 ppm over 1 day. After highlighting the main design enhancements with respect to state-of-the-art solutions, the CMRR measurement is reported. The output drift due to temperature and humidity is assessed to be negligible. Finally, the worst-case repeatability is measured both with shorted-to-ground inputs and with an applied common-mode voltage of 10 V, which represents the nominal working condition. PMID:26429481

  7. Evaluating Marie Byrd Land stability using an improved basal topography

    NASA Astrophysics Data System (ADS)

    Holschuh, N.; Pollard, D.; Alley, R. B.; Anandakrishnan, S.

    2014-12-01

    Prior understanding of the ice-sheet setting in Marie Byrd Land (MBL) was derived primarily from geologic and geochemical studies of the current nunataks, with very few geophysical surveys imaging the ice covered regions. The geologic context suggested that the ice rests on a broad regional high, in contrast to the deep basins and trenches that characterize the majority of West Antarctica. This assumed topography would favor long-term stability for the West Antarctic Ice Sheet (WAIS) in MBL. Airborne geophysical data collected in 2009 reveal a much deeper bed than previously estimated, including a significant trough underlying DeVicq Glacier and evidence for extensive glacial erosion. Using these data, we produce a new map of subglacial topography, with which we model the sensitivity of WAIS to a warming ocean using the ice-sheet model of Pollard and DeConto (2012b). We compare the results to estimates of ice loss during WAIS collapse using the previously defined subglacial topography, to determine the impact of the newly discovered subglacial features. Our results indicate that the topographic changes are not sufficient to destabilize the northern margin of MBL currently feeding the Getz Ice Shelf; the majority of ice loss occurs from flow toward the Siple Coast. However, despite only slight dynamic differences, using the new bed as a boundary condition results in an additional 8 cm of sea-level rise during major glacial retreat, an increase of just over 2%. Precise estimation of past and future ice retreat, as well as a complete understanding of the geologic history of the region, will require a higher resolution picture of the bed topography around the Executive Committee mountains.

  8. A perspective on coatings to stabilize high-voltage cathodes: LiMn1.5Ni0.5O4 with subnanometer Lipon cycled with LiPF6 electrolyte

    SciTech Connect

    Kim, Yoongu; Dudney, Nancy J; Chi, Miaofang; Martha, Surendra K; Nanda, Jagjit; Veith, Gabriel M; Liang, Chengdu

    2013-01-01

    High voltage Li-ion cathodes push the limits of stability for both cathode and electrolyte. Here subnanometer coatings of an amorphous thin film electrolyte (Lipon) improved the room temperature and 60 C cycling stability of a LiMn1.5Ni0.5O4 spinel cathode when charged to 4.9V with a standard LiPF6 carbonate electrolyte. The cathodes delivered superior C-rate performances up to a 5C discharge, when compared to the uncoated cathodes. Enhanced performance extended for at least 100 cycles. Electrochemical impedance spectroscopy indicates that Lipon slows the increase of interface resistance. Thicker 1-3nm Lipon coatings are sufficiently insulating as to block electronic transport to the cathode particles. Thick coatings also slow Mn dissolution. Results suggest that Lipon may act to scavenge impurities or block active sites that promote electrolyte decomposition. While greatly improved by the Lipon coating, this cathode is not sufficiently stable for long cycle life applications. Further work is needed to assess if and what surface coatings will ultimately stabilize the high voltage cathodes. Comments include insight from other studies of Lipon coated cathodes and directions for future research.

  9. PILOT-SCALE EVALUATION OF THE THERMAL STABILITY POHC INCINERABILITY RANKING

    EPA Science Inventory

    A test series were performed at the U.S. EPA Incineration Research Facility (IRF) to evaluate the thermal-stability-based principal organic hazardous constituent (POHC) incinerability ranking. ixtures of twelve POHCs with predicted incinerabilities spanning the range of most- to ...

  10. TECHNOLOGY EVALUATION REPORT: CHEMFIX TECHNOLOGIES, INC. - SOLIDIFICATION/STABILIZATION PROCESS - CLACKAMAS, OREGON - VOLUME II

    EPA Science Inventory

    The CHEMFIX solidification/stabilization process was evaluated in the U.S. Environmental Protection Agency's SITE program. Waste from an uncontrolled hazardous waste site was treated by the CHEMFIX process and subjected to a variety of physical and chemical test methods. Physical...

  11. TECHNOLOGY EVALUATION REPORT: CHEMFIX TECHNOLOGIES, INC. - SOLIDIFICATION/STABILIZATION PROCESS - CLACKAMAS, OREGON - VOLUME I

    EPA Science Inventory

    The CHEMFIX solidification/stabilization process was evaluated in the U.S. Environment Protection Agency's SITE program. Waste from an uncontrolled hazardous waste site was treated by the CHEMFIX process and subjected to a variety of physical and chemical test methods. Physical t...

  12. EVALUATION OF SOLIDIFICATION/STABILIZATION TREATMENT PROCESSES FOR MUNICIPAL WASTE COMBUSTION RESIDUES

    EPA Science Inventory

    Investigations were carried out to compare and evaluate solidification/stabilization (S/S) processes to treat residues from combustion (MWC). ull factorial experimental design was used to processes to treat bottom ash, air pollution control (APC) residue, The 5 S/S processes incl...

  13. Stability and Correlates of Student Evaluations of Teaching at a Chinese University

    ERIC Educational Resources Information Center

    Chen, Guo-Hai; Watkins, David

    2010-01-01

    This paper examines the stability and validity of a student evaluations of teaching (SET) instrument used by the administration at a university in the PR China. The SET scores for two semesters of courses taught by 435 teachers were collected. Total 388 teachers (170 males and 218 females) were also invited to fill out the 60-item NEO Five-Factor…

  14. Evaluation of the hok/sok Killer Locus for Enhanced Plasmid Stability

    E-print Network

    Wood, Thomas K.

    Evaluation of the hok/sok Killer Locus for Enhanced Plasmid Stability KuoweiWu and Thomas K. Wood 92777-2575 Received January 6, 7994lAcceptedJune 3, 7994 The effectiveness of the hoklsok plasmid of the hoklsok locus dra- matically increased apparent plasmid segregational sta- bility relative to the hoklsok

  15. 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...

  16. An evaluation of the contribution of radiation diffusion to thermal conductivity in high-pressure discharge lamps from operating-voltage and wall-temperature measurements

    NASA Astrophysics Data System (ADS)

    Born, M.

    1999-04-01

    The contribution of the radiation diffusion 0022-3727/32/8/007/img1 to the thermal conductivity 0022-3727/32/8/007/img2 in high-pressure discharge lamps is evaluated from operating-voltage and wall-temperature measurements for several cylindrical ceramic discharge tubes filled with mercury and argon as the rare gas. From calculations of 0022-3727/32/8/007/img1 using spectral line data of mercury, it is shown that the electrical conductivity 0022-3727/32/8/007/img4 can be well represented by a linear function of the heat-flux potential S. Under this assumption, the energy balance can be solved analytically and plasma parameters, i.e. radiation-diffusion and plasma-temperature profiles, can be calculated from the operating voltage and wall temperature without knowledge of spectral lines. The results are in good agreement with numerical calculations of the energy balance involving calculation of the radiation diffusion from spectral line data. The method may also be applied to other buffer gases for which there is a linear dependency of 0022-3727/32/8/007/img5. This may be checked qualitatively by measurement of the temporal evolution of the operating voltage using the Cassie-Francis equation.

  17. 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...

  18. Evaluation of Laser Stabilization and Imaging Systems for LCLS-II - Final Paper

    SciTech Connect

    Barry, Matthew

    2015-08-20

    By combining the top performing commercial laser beam stabilization system with the most ideal optical imaging configuration, the beamline for the Linear Accelerator Coherent Light Source II (LCLS-II) will deliver the highest quality and most stable beam to the cathode. To determine the optimal combination, LCLS-II beamline conditions were replicated and the systems tested with a He-Ne laser. The Guidestar-II and MRC active laser beam stabilization systems were evaluated for their ideal positioning and stability. Both a two and four lens optical imaging configuration was then evaluated for beam imaging quality, magnification properties, and natural stability. In their best performances when tested over fifteen hours, Guidestar-II kept the beam stable over approximately 70-110um while the MRC system kept it stable over approximately 90-100um. During short periods of time, Guidestar-II kept the beam stable between 10-20um, but was more susceptible to drift over time, while the MRC system maintained the beam between 30-50um with less overall drift. The best optical imaging configuration proved to be a four lens system that images to the iris located in the cathode room and from there, imaged to the cathode. The magnification from the iris to the cathode was 2:1, within an acceptable tolerance to the expected 2.1:1 magnification. The two lens configuration was slightly more stable in small periods of time (less than 10 minutes) without the assistance of a stability system, approximately 55um compared to approximately 70um, but the four lens configurations beam image had a significantly flatter intensity distribution compared to the two lens configuration which had a Gaussian distribution. A final test still needs to be run with both stability systems running at the same time through the four lens system. With this data, the optimal laser beam stabilization system can be determined for the beamline of LCLS-II.

  19. Evaluation of protein drug stability with vitreous humor in a novel ex-vivo intraocular model.

    PubMed

    Patel, Sulabh; Müller, Gerd; Stracke, Jan Olaf; Altenburger, Ulrike; Mahler, Hanns-Christian; Jere, Dhananjay

    2015-09-01

    The stability of protein therapeutics during the residence time in the vitreous humor (VH) is an important consideration for intra ocular treatment and can possibly impact therapeutic efficacy and/or treatment intervals. Unavailability of the reliable Ex-vivo intravitreal (ExVit) model to estimate protein stability following IVT has driven the research focus to develop such model which can facilitate protein stability estimation before in-vivo experiments. In this manuscript, we have developed and evaluated three ExVit models, namely, ExVit static, semi-dynamic and dynamic. These models were utilized and compared when studying the in-vitro stability of model protein formulations under simulated intraocular conditions using porcine vitreous humor (VH). The ExVit static model exhibited significant precipitation and aggregation of proteins, most likely due to pH change occurred in the VH after isolation. The semi-dynamic model assessed was composed of two compartments i.e., VH- and buffer-compartment which has effectively stabilized the pH of the VH and facilitated the migration of VH degradation products. However, some limitations related to investigation of long-term protein stability were also observed with semi-dynamic model. The dynamic model developed, was comprised of three diffusion controlling barriers (two diffusion controlling membranes and a gel-matrix), which allowed modulation of the diffusion rate of macromolecules. The ability of dynamic model to modulate protein retention time in the VH will overcome the challenges faced by the semi-dynamic model such as long-term stability evaluation. PMID:26032291

  20. 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.

  1. Evaluation of Stability Changes in Tapered and Parallel Wall Implants: A Human Clinical Trial

    PubMed Central

    Rokn, AR.; Ghahroudi, AAR. Rasouli; Mesgarzadeh, A.; Miremadi, AA.; Yaghoobi, S.

    2011-01-01

    Objective To determine the pattern of stability changes as a reflection of early healing around single-stage roughened-surface implants in humans utilizing resonance frequency analysis (RFA). Materials and Methods Hundred twenty-five patients who demanded dental implants were treated with two different implant (Nobel Biocare Replace™ and Strumman™ ITI) systems. Bone type was classified into four groups. RFA was used for direct measurement of implant stability on the day of implant placement and consecutively at 14, 30 and 60 days after placement. The data were analyzed with Student t test and regression analysis. Results Three-hundred four roughened surface implants placed in the maxilla and mandible were evaluated. In Replace™ implants the lowest mean stability measurement was at 30 days for all bone types and the stability did not change significantly in any of the bone types (p>0.05). ITI™ implants demonstrated the lowest stability at 60 days for type 1 and 30 days and baseline for type 2, 3 and 4 bones. In addition, there was significant differences in implant stability between bone types 1 and 4 (P<0.001), 2 and 3 (p<0.05), and bone types 3 and 4 (P=0.07) at all aforementioned times in ITI™ implants. In Replace™ implants, regarding the implant diameter, contrary to ITI implants, no significant stability changes were detected (p>0.05). No significant difference was observed regarding gender, age and lengths in both systems. Conclusion In comparison to ITI™ implants, Replace™ implants revealed no significant difference in the pattern of stability changes among different bone types. PMID:22509458

  2. 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.

  3. Soil stabilization using oil shale solid wastes: Laboratory evaluation of engineering properties

    SciTech Connect

    Turner, J.P.

    1991-01-01

    Oil shale solid wastes were evaluated for possible use as soil stabilizers. A laboratory study was conducted and consisted of the following tests on compacted samples of soil treated with water and spent oil shale: unconfined compressive strength, moisture-density relationships, wet-dry and freeze-thaw durability, and resilient modulus. Significant increases in strength, durability, and resilient modulus were obtained by treating a silty sand with combusted western oil shale. Moderate increases in strength, durability, and resilient modulus were obtained by treating a highly plastic clay with combusted western oil shale. Solid waste from eastern shale can be used for soil stabilization if limestone is added during combustion. Without limestone, eastern oil shale waste exhibits little or no cementation. The testing methods, results, and recommendations for mix design of spent shale-stabilized pavement subgrades are presented. 11 refs., 3 figs., 10 tabs.

  4. 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

  5. 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.

  6. Evaluation of Energy Characteristics of High Voltage Equipment for Electro-Blasting Destruction of Rocks and Concrete

    NASA Astrophysics Data System (ADS)

    Voitenko, N. V.; Yudin, A. S.; Kuznetsova, N. S.

    2015-11-01

    The splitting off concrete monolith via electro-blast technology is described. High- voltage investigations were performed using the electric-discharge blasting unit with charging voltage up to 15 kV and maximum energy of 126 kJ. Several series of experiments of multiborehole electro-blast with initiation of plasma channel by wire explosion have been carried out. The combined effect of pulse electric discharge and gas generating composition allows to increase the energy of electro-blasting. According to data obtained from experiments the average value of energy for concrete monolith splitting off of 1 m3 is about 1554 kJ. The energy of electrical discharge pulse is about 95 kJ and gas-generating composition has energy contribution of 3.8 kJ/g. For carrying out of one electric-discharge blasting experiment 6-8 minutes has been spent. Therefore, the efficiency of pulse power system is about (0.85-0.9) m3/h.

  7. Methodologies for evaluating long-term stabilization designs of uranium mill tailings impoundments

    SciTech Connect

    Nelson, J.D.; Abt, S.R.; Volpe, R.L.; Van Zye, D.; Hinkle, N.E.; Staub, W.P.

    1986-06-01

    Uranium mill tailings impoundments require long-term (200 to 1000 years) stabilization. This report reviews currently available methodologies for evaluating factors that can have a significant influence on tailings stabilization and develops methodologies in technical areas where none presently exist. Mill operators can use these methodologies to assist with (1) the selection of sites for mill tailings impoundments, (2) the design of stable impoundments, and (3) the development of reclamation plans for existing impoundments. These methodologies would also be useful for regulatory agency evaluations of proposals in permit or license applications. Methodologies were reviewed or developed in the following technical areas: (1) prediction of the Probable Maximum Precipitation (PMP) and an accompanying Probable Maximum Flood (PMF); (2) prediction of the stability of local and regional fluvial systems; (3) design of impoundment surfaces resistant to gully erosion; (4) evaluation of the potential for surface sheet erosion; (5) design of riprap for protecting embankments from channel flood flow and overland flow; (6) selection of riprap with appropriate durability for its intended use; and (7) evaluation of oversizing required for marginal quality riprap.

  8. Evaluation of Rotordynamic Stability of a Steam Turbine Due to Labyrinth Seal Force

    NASA Astrophysics Data System (ADS)

    Hirano, Toshio; Sasaki, Takashi; Sakakida, Hitoshi; Uchida, Tatsuro; Tsutsui, Masaji; Ikeda, Kazunori

    This paper describes the evaluation of unstable vibration caused by the seal force, which is known as "Steam Whirl" in a steam turbine. Stability of a steam turbine is evaluated by complex eigenvalue analysis of rotordynamics model considering the dynamics of seals, rotor, bearings and pedestals. A commercial CFD program is employed to estimate the dynamic coefficients of labyrinth seal. The labyrinth seal of a large scales steam turbine is taken as an object of analysis and a 3D model with eccentric rotor is solved to obtain the rotordynamic force components. The rotordynamic force is derived by integrating the pressure on the rotor surface. Evaluation formula is formed from the results of numerical calculation, which is used to predict the dynamic coefficient of each seal in a steam turbine. Then rotordynamics model of total system including seal is constructed and stability is evaluated by complex eigenvalue analysis. This procedure is applied to the design of steam turbines and enables the optimization of the turbine structure considering the efficiency and stability.

  9. 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

  10. 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

  11. pH stability and comparative evaluation of ranaspumin-2 foam for application in biochemical reactors

    NASA Astrophysics Data System (ADS)

    Choi, Hyo-Jick; Ebersbacher, Charles F.; Quan, Fu-Shi; Montemagno, Carlo D.

    2013-02-01

    Aqueous channels of foam represent a simplified, natural bioreactor on the micro-/nano-scale. Previous studies have demonstrated the feasibility and potential application of foams in replicating cellular process in vitro, but no research has been performed to establish a basis for designing stable and biocompatible foam formulations. Our research has been directed specifically to the evaluation of ranaspumin-2 (RSN-2), a frog foam nest protein. The strong surfactant activity of RSN-2 enabled us to produce foams using low protein concentration (1 mg ml-1) over a wide pH range (pH ? 3). Importantly, the RSN-2 formulation exhibited the best foam stability at a near neutral pH condition, which shows a potential for application to various biosynthesis applications. Model cellular systems such as liposomes and inactivated A/PR/8/34 influenza virus maintained their physicochemical stability and full hemagglutination activity, indicating biocompatibility of RSN-2 with both cellular membranes and proteins both in bulk solution and in foam. Moreover, the addition of RSN-2 did not exert any deteriorative effects on bacterial cell growth kinetics. In contrast, Tween 20, Triton X-100, and BSA did not show satisfactory performance in terms of foamability, foam stability, physicochemcial stability, and biochemical stability. Although our study has been limited to representative formulations composed of only surfactant molecules, a number of unique advantages make RSN-2 a promising candidate for in vitro foam biosynthesis.

  12. Incorporating voltage security into the planning, operation and monitoring of restructured electric energy markets

    NASA Astrophysics Data System (ADS)

    Nair, Nirmal-Kumar

    As open access market principles are applied to power systems, significant changes are happening in their planning, operation and control. In the emerging marketplace, systems are operating under higher loading conditions as markets focus greater attention to operating costs than stability and security margins. Since operating stability is a basic requirement for any power system, there is need for newer tools to ensure stability and security margins being strictly enforced in the competitive marketplace. This dissertation investigates issues associated with incorporating voltage security into the unbundled operating environment of electricity markets. It includes addressing voltage security in the monitoring, operational and planning horizons of restructured power system. This dissertation presents a new decomposition procedure to estimate voltage security usage by transactions. The procedure follows physical law and uses an index that can be monitored knowing the state of the system. The expression derived is based on composite market coordination models that have both PoolCo and OpCo transactions, in a shared stressed transmission grid. Our procedure is able to equitably distinguish the impacts of individual transactions on voltage stability, at load buses, in a simple and fast manner. This dissertation formulates a new voltage stability constrained optimal power flow (VSCOPF) using a simple voltage security index. In modern planning, composite power system reliability analysis that encompasses both adequacy and security issues is being developed. We have illustrated the applicability of our VSCOPF into composite reliability analysis. This dissertation also delves into the various applications of voltage security index. Increasingly, FACT devices are being used in restructured markets to mitigate a variety of operational problems. Their control effects on voltage security would be demonstrated using our VSCOPF procedure. Further, this dissertation investigates the application of steady state voltage stability index to detect potential dynamic voltage collapse. Finally, this dissertation examines developments in representation, standardization, communication and exchange of power system data. Power system data is the key input to all analytical engines for system operation, monitoring and control. Data exchange and dissemination could impact voltage security evaluation and therefore needs to be critically examined.

  13. Stable low noise voltage source

    NASA Technical Reports Server (NTRS)

    Lutes, G. F.

    1978-01-01

    Hum and noise on power sources can have a significant effect on system noise. Filtering to achieve low hum and noise is accomplished at low current levels. The diode regulator circuit is described which is ideal for this type of filtering. Hum and noise rejection is achieved with good output voltage stability in a small, low-cost, reliable circuit.

  14. 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.

  15. 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.

  16. Field soil aggregate stability kit for soil quality and rangeland health evaluations

    USGS Publications Warehouse

    Herrick, J.E.; Whitford, W.G.; de Soyza, A. G.; Van Zee, J. W.; Havstad, K.M.; Seybold, C.A.; Walton, M.

    2001-01-01

    Soil aggregate stability is widely recognized as a key indicator of soil quality and rangeland health. However, few standard methods exist for quantifying soil stability in the field. A stability kit is described which can be inexpensively and easily assembled with minimal tools. It permits up to 18 samples to be evaluated in less than 10 min and eliminates the need for transportation, minimizing damage to soil structure. The kit consists of two 21??10.5??3.5 cm plastic boxes divided into eighteen 3.5??3.5 cm sections, eighteen 2.5-cm diameter sieves with 1.5-mm distance openings and a small spatula used for soil sampling. Soil samples are rated on a scale from one to six based on a combination of ocular observations of slaking during the first 5 min following immersion in distilled water, and the percent remaining on a 1.5-mm sieve after five dipping cycles at the end of the 5-min period. A laboratory comparison yielded a correlation between the stability class and percent aggregate stability based on oven dry weight remaining after treatment using a mechanical sieve. We have applied the method in a wide variety of agricultural and natural ecosystems throughout western North America, including northern Mexico, and have found that it is highly sensitive to differences in management and plant community composition. Although the field kit cannot replace the careful laboratory-based measurements of soil aggregate stability, it can clearly provide valuable information when these more intensive procedures are not possible.

  17. Low operation voltage and high thermal stability of a WSi2 nanocrystal memory device using an Al2O3/HfO2/Al2O3 tunnel layer

    NASA Astrophysics Data System (ADS)

    Uk Lee, Dong; Jun Lee, Hyo; Kyu Kim, Eun; You, Hee-Wook; Cho, Won-Ju

    2012-02-01

    A WSi2 nanocrystal nonvolatile memory device was fabricated with an Al2O3/HfO2/Al2O3 (AHA) tunnel layer and its electrical characteristics were evaluated at 25, 50, 70, 100, and 125 °C. The program/erase (P/E) speed at 125 °C was approximately 500 ?s under threshold voltage shifts of 1 V during voltage sweeping of 8 V/-8 V. When the applied pulse voltage was ±9 V for 1 s for the P/E conditions, the memory window at 125 °C was approximately 1.25 V after 105 s. The activation energies for the charge losses of 5%, 10%, 15%, 20%, 25%, 30%, and 35% were approximately 0.05, 0.11, 0.17, 0.21, 0.23, 0.23, and 0.23 eV, respectively. The charge loss mechanisms were direct tunneling and Pool-Frenkel emission between the WSi2 nanocrystals and the AHA barrier engineered tunneling layer. The WSi2 nanocrystal memory device with multi-stacked high-K tunnel layers showed strong potential for applications in nonvolatile memory devices.

  18. Improved rate capability and cycle stability of Li[Ni0.5Co0.2Mn0.3]O2 with Li2MnO3 coating under high cut-off voltage

    NASA Astrophysics Data System (ADS)

    Liu, Ting; Zhao, Shi-Xi; Wang, Ke-Zhen; Gou, Lu-Lu; Nan, Ce-Wen

    2015-11-01

    The structure and electrochemical performance of Li2MnO3-coated Li[Ni0.5Co0.2Mn0.3]O2 cathode were investigated. The results demonstrated that the Li2MnO3-coated Li[Ni0.5Co0.2Mn0.3]O2 sample exhibited an improved electrochemical performance at room and elevated temperatures, especially at a high cut-off voltage range. The capacity retention of the 1.0 mol% Li2MnO3-coated sample after 100 cycles was 78% at 3.0-4.3 V, in comparison with that of 57% for the pristine one at room temperature. Interestingly, after 200 cycles, the 4.0 mol% Li2MnO3-coated cathode showed the best cycle stability with capacity retention as high as 37% when the cut-off voltage was increased to 4.8 V, while it was only 2% for the pristine sample. The cyclability of Li[Ni0.5Co0.2Mn0.3]O2 at high temperature was also slightly improved with Li2MnO3 coating.

  19. 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.

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

    NASA Technical Reports Server (NTRS)

    Rising, J. J.; Kairys, A. A.; Maass, C. A.; Siegart, C. D.; Rakness, W. L.; Mijares, R. D.; King, R. W.; Peterson, R. S.; Hurley, S. R.; Wickson, D.

    1982-01-01

    A limited authority pitch active control system (PACS) was developed for 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. The piloted flight simulation and vehicle system simulation tests performed to verify control laws and system operation prior to installation on the aircraft are discussed. Modifications to the basic aircraft are described. Flying qualities of the aircraft with the PACS on and off were evaluated. Handling qualities for cruise and high speed flight conditions with the c.g. at 39% mac ( + 1% stability margin) and PACS operating were judged to be as good as the handling qualities with the c.g. at 25% (+15% stability margin) and PACS off.

  1. Evaluation of bias voltage modulation sequence for nonlinear contrast agent imaging using a capacitive micromachined ultrasonic transducer array.

    PubMed

    Novell, Anthony; Legros, Mathieu; Grégoire, Jean-Marc; Dayton, Paul A; Bouakaz, Ayache

    2014-09-01

    Many clinical diagnoses have now been improved thanks to the development of new techniques dedicated to contrast agent nonlinear imaging. Over the past few years, Capacitive Micromachined Ultrasonic Transducers (cMUTs) have emerged as a promising alternative to traditional piezoelectric transducers. One notable advantage of cMUTs is their wide frequency bandwidth. However, their use in nonlinear imaging approaches such as those used to detect contrast agents have been challenging due their intrinsic nonlinear character. We propose a new contrast imaging sequence, called bias voltage modulation (BVM), specifically developed for cMUTs to suppress their inherent nonlinear behavior. Theoretical and experimental results show that a complete cancellation of the nonlinear signal from the source can be reached when the BVM sequence is implemented. In-vitro validation of the sequence is performed using a cMUT probe connected to an open scanner and a flow phantom setup containing SonoVue microbubbles. Compared to the standard amplitude modulation imaging mode, a 6?dB increase of contrast-to-tissue ratio was achieved when the BVM sequence is applied. These results reveal that the problem of cMUT nonlinearity can be addressed, thus expanding the potential of this new transducer technology for nonlinear contrast agent detection and imaging. PMID:25098319

  2. Evaluation of bias voltage modulation sequence for nonlinear contrast agent imaging using a capacitive micromachined ultrasonic transducer array

    NASA Astrophysics Data System (ADS)

    Novell, Anthony; Legros, Mathieu; Grégoire, Jean-Marc; Dayton, Paul A.; Bouakaz, Ayache

    2014-09-01

    Many clinical diagnoses have now been improved thanks to the development of new techniques dedicated to contrast agent nonlinear imaging. Over the past few years, Capacitive Micromachined Ultrasonic Transducers (cMUTs) have emerged as a promising alternative to traditional piezoelectric transducers. One notable advantage of cMUTs is their wide frequency bandwidth. However, their use in nonlinear imaging approaches such as those used to detect contrast agents have been challenging due their intrinsic nonlinear character. We propose a new contrast imaging sequence, called bias voltage modulation (BVM), specifically developed for cMUTs to suppress their inherent nonlinear behavior. Theoretical and experimental results show that a complete cancellation of the nonlinear signal from the source can be reached when the BVM sequence is implemented. In-vitro validation of the sequence is performed using a cMUT probe connected to an open scanner and a flow phantom setup containing SonoVue microbubbles. Compared to the standard amplitude modulation imaging mode, a 6?dB increase of contrast-to-tissue ratio was achieved when the BVM sequence is applied. These results reveal that the problem of cMUT nonlinearity can be addressed, thus expanding the potential of this new transducer technology for nonlinear contrast agent detection and imaging.

  3. 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.

  4. Intrinsic Surface Stability in LiMn2-xNix04-s (x = 0.45, 0.5) High Voltage Spinel Materials for Lithium Ion Batteries

    SciTech Connect

    Carroll, Kyler J; Yang, Ming-Che; Veith, Gabriel M; Dudney, Nancy J; Meng, Ying Shirley

    2012-01-01

    This work reports the surface stability of the high vollage Li ion cathode LiMn2_,Ni,Ooh\\ (x = 0.5, 0.45) by comparing thin fi lm and powder composite electrodes after cycling using X-ray photoelectron spectroscopy. The thin film electrodes offer the abili ty to probe the surface of the material without the need of a conductive agent and polymer binder typically used in composite electrodes. The resulls suggest that neither oxidation of PP6 to POF3 nor the decomposition of ethylene carbonate or dimethylene carbonate occurs on the surface of the spinel material. These resulls confirm the enhanced cycling stability and rate capability associated with the high vollage spinel material and suggests that the SE!IIayer fonns due to the reaction of electrochemically inactive components in composite electrodes with the electrolyte.

  5. 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...

  6. Evaluation of the geological relationships to gas hydrate formation and stability

    SciTech Connect

    Not Available

    1986-01-01

    Although there are many publications pertaining to gas hydrates, their formation and stability in various geological conditions are poorly known. Therefore, for the same reasons and because of the very broad scope of our research, limited amount and extremely dispersed information, the study regions are very large. Moreover, almost without exception the geological environments controlling gas hydrates formation and stability of the studied regions are very complex. The regions studied (completed and partially completed - total 17 locations) during the reporting period, particularly the Gulf of Mexico and the Middle America Trench, are the most important in this entire research project. In the past, both of these regions have been extensively studied, the presence of gas hydrates confirmed and samples recovered. In our investigation it was necessary not only to review all previous data and interpretations, but to do a thorough analysis of the basins, and a critical evaluation of an previously reported and publicly available but not published information.

  7. An evaluation of the stability of synthetic groundwater formulations GR-3 and GR-4

    SciTech Connect

    Dill, J.A.; Jones, T.E.; Marcy, A.D.; Baechler, M.O.; Payne, J.R.

    1984-10-08

    Simple solubility calculations indicate that synthetic groundwater formulations GR-3 and GR-4 may be unstable with respect to the precipitation of certain components. However, the validity of calculations of this type is limited by the complexity of these solutions. In order to properly address the chemical stability of these formulations, an experimental evaluation has been accomplished. The findings were that GR-3 and GR-4 were similar in their chemical stability. Both were found to be quite stable with respect to all constituents except silicate and inorganic carbon over a 30-day period. Some instability of monomeric silicate was observed. However, this did not result in a concentration change of greater than 5%, and no evidence of particulate formation was observed. 6 refs., 30 tabs.

  8. 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.

  9. Performance Evaluation and Slip Regulation Control of an Asymmetrical Parameter Type Two-Phase Induction Motor Drive Using a Three-Leg Voltage Source Inverter

    NASA Astrophysics Data System (ADS)

    Piyarat, Wekin; Kinnares, Vijit

    This paper presents a performance evaluation and a simple speed control method of an asymmetrical parameter type two-phase induction motor drive using a three-leg VSI (Voltage Source Inverter). The two-phase induction motor is adapted from an existing single-phase induction motor resulting in impedance unbalance between main and auxiliary windings. The unbalanced two-phase inverter outputs with orthogonal displacement based on a SPWM (Sinusoidal Pulse Width Modulation) method are controlled with appropriate amplitudes for improving the motor performance. Dynamic simulation of the proposed drive system is given. A simple speed controller based on a slip regulation method is designed. The overall system is implemented on a DSP (Digital Signal Processor) board. The validity of the proposed system is verified by simulation and experimental results.

  10. Design and flight performance evaluation of the Mariners 6, 7, and 9 short-circuit current, open-circuit voltage transducers

    NASA Technical Reports Server (NTRS)

    Patterson, R. E.

    1973-01-01

    The purpose of the short-circuit voltage transducer is to provide engineering data to aid the evaluation of array performance during flight. The design, fabrication, calibration, and in-flight performance of the transducers onboard the Mariner 6, 7 and 9 spacecrafts are described. No significant differences were observed in the in-flight electrical performance of the three transducers. The transducers did experience significant losses due to coverslides or adhesive darkening, increased surface reflection, or spectral shifts within coverslide assembly. Mariner 6, 7 and 9 transducers showed non-cell current degradations of 3-1/2%, 3%, and 4%, respectively at Mars encounter and 6%, 3%, and 4-12%, respectively at end of mission. Mariner 9 solar Array Test 2 showed 3-12% current degradation while the transducer showed 4-12% degradation.

  11. Effects of sample storage on biosolids compost stability and maturity evaluation.

    PubMed

    Wu, L; Ma, L Q

    2001-01-01

    Compost stability and maturity are important parameters of compost quality. To date, nearly all compost characterization has been performed using samples freshly collected because sample storage can affect compost stability and maturity evaluation. However, sample preservation is sometimes necessary, especially for scientific research purposes. There is little information available on the effects of sample storage on compost stability and maturity. Samples of biosolids compost with different levels of stability and maturity were collected from four compost facilities in Florida (referred to as Register, Winslow, Sunset, and Meadow). Comparisons of CO2 evolution, seed germination rate, and water-soluble organic carbon (WSOC) were made between fresh samples with short storage at 4 degrees C for less than 1 wk and air-dried or frozen compost samples stored for 1 yr. The effects of storage (air-dry or frozen) on the measured parameters depended on compost stability and maturity and on the compost material source. Frozen storage reduced the peak CO2 evolution of Register samples by 12 to 29%, while accumulated CO2 evolution was reduced by 43 to 64% and 110 to 277% with air-dry and frozen storage, respectively. The storage effect on CO2 evolution with more stable compost was inconsistent. Storage did not affect compost phytotoxicity, except for samples from the Sunset facility. Air-drying reduced the WSOC by up to 35%, and freezing increased it by up to 34%, while both storage methods had no significant effect on samples of low WSOC. Despite all these variations, WSOC had a significant and consistent relation to CO2 evolution and seed germination rates with R2 of 0.78 and 0.57, respectively, regardless of storage methods. PMID:11215657

  12. 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

  13. 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.

  14. ALD gate dielectrics for improved threshold voltage stability in AlGaN/GaN MOS-HFETs for power applications

    NASA Astrophysics Data System (ADS)

    Ramanan, Narayanan; Lee, Bongmook; Misra, Veena

    2015-12-01

    Dielectrics by atomic layer deposition (ALD) are sought after for fabricating AlGaN/GaN based metal oxide semiconductor heterojunction field effect transistors (MOS-HFETs) for power applications. The ideal gate dielectric is required to suppress gate leakage and minimize threshold voltage (V T) instability by hosting minimal interface traps. Additionally, with the need for an enhancement mode device, it is preferable if it minimizes V T shift in the negative direction. For the first time, we compare popular ALD dielectrics like SiO2, Al2O3, HfO2 and HfAlO with identical electrical thickness on AlGaN/GaN, thereby ensuring identical electrostatic conditions across different dielectrics. High-k ALD dielectrics (HfAlO, HfO2 and Al2O3) are found to suppress gate leakage but host a high density of interface traps with AlGaN, thereby resulting in significant V T instability. ALD SiO2 gate dielectric, annealed in N2 above 600 °C, is a promising gate dielectric candidate which provides the most stable and least negative shift in V T while also substantially suppressing gate leakage below that of an HFET.

  15. Mesoporous templated silicates: an overview of their synthesis, catalytic activation and evaluation of the stability.

    PubMed

    Linssen, T; Cassiers, K; Cool, P; Vansant, E F

    2003-04-25

    The most recent developments in the formation of new mesoporous templated zeolitic materials, characterized by surfaces of more than 1000 m(2)/g, are discussed in this paper. By adapting the synthesis parameters, such as type of silicium source, type of template, pH, temperature, em leader different materials can be synthesized with varying porosity and crystallinity. Besides the synthesis, much attention is focused on the activation of their surfaces by incorporation methods or deposition processes towards catalytic applications. Finally, the stability of the different materials, one of the critical parameters to potential industrial applications, is compared and evaluated. PMID:12706552

  16. Reliability of a New Stabilized Dynamometer System for the Evaluation of Hip Strength

    PubMed Central

    Tourville, Timothy W.; Smith, Helen C.; Shultz, Sandra J.; Vacek, Pamela M.; Slauterbeck, James R.; Johnson, Robert J.; Beynnon, Bruce D.

    2013-01-01

    Background: Hip strength is associated with numerous orthopaedic and neuromuscular injuries and/or pathologies and may be assessed with a variety of anatomic testing positions and techniques. Isokinetic dynamometers are generally too cumbersome and intricate for efficient use in mass screenings (for prognostic studies of risk for injury) as well as with special populations. The reliability of isometric testing devices has demonstrated varied reliability, generally examining only 1 or 2 motions of the hip and reporting values of force, not torque. Consequently, there is a need for an efficient hip strength-testing device to quantify torque that tests subjects in 1 anatomic position, while evaluating multiple hip motions. Hypothesis: Evaluation of supine hip abduction, adduction, flexion, and extension torque using a new stabilized dynamometer system will produce good to excellent intra- and interexaminer reliability results. Study Design: A blinded, randomized, repeated-measures study design was used in this descriptive laboratory investigation. Methods: Supine isometric hip flexion, extension, abduction, and adduction torques were evaluated with a cage-stabilized dynamometer in 19 collegiate and professional-level ice hockey athletes by 2 investigators at 3 time intervals. Inter- and intrarater reliability was assessed. Results: Supine hip flexion, extension, abduction, and adduction torque was performed with good to excellent inter- and intrarater reliability (intraclass correlation coefficients ranging from 0.74 to 0.92 and 0.78 to 0.92, respectively) for all motions tested. Conclusions: We have developed an isometric hip strength-testing device that can be assembled around an examination table to efficiently and reliably evaluate torque developed for multiple motions of the hip. Clinical Relevance: This device and testing protocol may be used to efficiently evaluate hip strength in numerous settings; it allows decreased subject burden and increased comfort (which may be important following an injury in case-control investigations); and it may be well tolerated when testing athletes as well as special populations in the clinical setting. PMID:24427380

  17. Soy milk as an emulsifier in mayonnaise: physico-chemical, stability and sensory evaluation.

    PubMed

    Rahmati, Kobra; Mazaheri Tehrani, Mostafa; Daneshvar, Kazem

    2014-11-01

    Mayonnaise is an oil in water emulsion and egg components are its emulsifier. In this research application of soy milk to stabilize mayonnaise was studied. Egg was replaced with full fat soy flour-prepared soy milk at levels of 25, 50, 75, and 100 % and microstructure, stability, color, viscosity and sensory analysis were performed and results were compared with those of control samples containing yolk and whole egg as emulsifier. Results showed that yolk-prepared control (YC) had higher stability and viscosity values and the value of these two attributes decreased as more amounts of soy milk was used. In the case of viscosity there was no statistical difference between soy milk-prepared samples and egg-prepared control (EC) up to 75 % replacement. Color factors changed, which were affected by different proportions of soy milk. Sensory evaluation showed no statistical difference in acceptability of EC and samples with substitution levels up to 50 %. So it can be concluded that egg can be substituted with soy milk in mayonnaise. PMID:26396329

  18. Evaluation of hydrothermal treatment in enhancing rice straw compost stability and maturity.

    PubMed

    Nakhshiniev, Bakhtiyor; Biddinika, Muhammad Kunta; Gonzales, Hazel Bantolino; Sumida, Hiroaki; Yoshikawa, Kunio

    2014-01-01

    In order to evaluate the hydrothermal treatment (HTT) in enhancing compost stability and maturity of lignocellulosic agricultural residues, a bin-scale (90 L) composting of rice straw with and without "HTT" was performed. The rice straw compost product with "HTT" after 6 weeks of composting can be considered stable and adequate for field application as expressed by pH of 8.4, "EC value" of 2.96 dS m(-1), C/N ratio of 12.5, microbial activity of <8.05 mg CO2 g(-1) OM d(-1), NH4(+)-N content of 93.75 mg kg(-1) DM and finally, by "GI" of >83%. However, compost may prove phytotoxic if used as growing media for EC sensitive plants. As for rice straw compost product without "HTT", the high microbial activity (>12.28 mg CO2 g(-1) OM d(-1)) even after 14 weeks of composting suggests that the residue has not stabilized yet and is far away from stability and maturity, although a higher GI (>100%) was observed. PMID:24262840

  19. Development and stability evaluation of olive oil nanoemulsion using sucrose monoester laurate

    NASA Astrophysics Data System (ADS)

    Eid, Ahmad M. M.; Baie, Saringat Haji; Arafat, Osama

    2012-11-01

    Nanoemulsion is a type of emulsion that consists of fine oil-in-water dispersions, with the droplets covering the size range of 20-200 nm. It can be achieved through emulsification process. One of the processes is through low energy emulsification method. Olive oil was chosen in this study due to its efficiency in treating skin problem. Olive oil nanophase gel (NPG) formulations were performed through various ratios of olive oil, sucrose laurate and glycerin. The particle sizes and stability of the prepared olive oil nanophase gel were evaluated and the optimal formulation was then selected for the development of olive oil nanoemulsion. This study proved that the composition of oil and surfactant play an important roles in influencing the nanophase gel droplet size. Nanophase gels containing olive oil in the concentration of 50 and 60 % show good stability at 4 °C and room temperature while it was less stable at 40 °C. Olive oil nanophase gels in the concentration of 50 % and 60 % with sucrose laurate 25 % in each formulation were good candidates to prepare nanoemulsion because they have the suitable droplets size and Polydispersing Index (PDI) when compared to other formulations. A mixture of NPG 50 % and water in the ratio of 40:60 and NPG 60 % and water in the ratio of 33.3:66.7 were used to produce nanoemulsions containing 20 % of oil with negative values of zeta potential (>60) which indicate the good stability of the nanoemulsions.

  20. Monitoring of leachate quality stored in gas ventilation pipes for evaluating the degree of landfill stabilization.

    PubMed

    Tojo, Yasumasa; Sato, Masahiro; Matsuo, Takayuki; Matsuto, Toshihiko

    2011-01-01

    Monitoring of leachate quality is the essential measure in aftercare for evaluating landfill stabilization. Generally, the most common way of leachate monitoring is executed at the inlet of the leachate treatment facility. However, it does not necessarily reflect the actual state of the site. Thus, methodologies which focus on both the discharge, in order to determine when the post-closure care of the facility should terminate, and on the degree of waste stabilization in the landfill are required. In the present study, monitoring of leachate quality stored in 68 gas ventilation pipes was conducted and the degree of waste stabilization at each location in the landfill was estimated by a statistical approach using the results obtained by monitoring. Leachate characteristics varied significantly for each pipe but seemed to reflect the waste condition of the nearby location. Correlation among the analysed items was quite high. Namely, the difference of leachate quality seemed to be categorized only by the level of concentration but not by the specific characteristics. To confirm this, Euclidean distances of dissimilarity were calculated by multidimensional scaling using six items of leachate quality and temperature. Two factors (thickness of leachate and concentration of total organic carbon (TOC) and electric conductivity (EC)) that distinguish leachate characteristics appeared. To indicate the degree of stabilization by location, the spatial distribution of TOC, total nitrogen (TN), inorganic carbon (IC), and chloride ion were estimated by using the ordinary Kriging methodology. As the result, it was estimated that the concentration of leachate existing within the landfill, especially TN, was higher than the completion criteria for leachate in most parts of the investigated area. PMID:20937618

  1. Long Term Stability Evaluation of Prostacyclin Released from Biomedical Device through Turbiscan Lab Expert.

    PubMed

    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; Di Marzio, Luisa; 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

  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. An evaluation of the stability of synthetic Grande Ronde groundwater formulations GR-3 and GR-4

    SciTech Connect

    Dill, J.A.; Jones, T.E.; Marcy, A.D.; Baechler, M.O.; Payne, J.R.

    1987-03-01

    Simple solubility calculations indicate that synthetic Grande Ronde groundwater formulations GR-3 and GR-4 may be unstable with respect to the precipitation of certain components. The validity of calculations of this type is, however, limited by the complexity of the solutions. To address the chemical stability of these formulations properly, an experimental evaluation was performed. The evaluation revealed that GR-3 and GR-4 were similar in their chemical stability. Both were found to be quite stable with respect to all constituents, except silicate and inorganic carbon, over a 30-d period. Some instability of monomeric silicate was observed. However, this did not result in a concentration change of greater than 5%, and no evidence of particulate formation was observed. Both formulations were found to be relatively unstable with respect to inorganic carbon concentration. A general trend toward increasing carbon concentration was observed. This was attributed to absorption of CO/sub 2/ from the atmosphere. Storing the synthetic groundwater in sealed containers eliminated this problem. 5 refs., 24 tabs.

  5. Mine stability evaluation of panel 1 during waste emplacement operations at WIPP

    SciTech Connect

    Maleki, H.

    1998-07-01

    The specific objectives of the work were defined by the Environmental Evaluation Group (EEG) as follows: (1) assess the stability of panel 1 during the proposed operation of waste emplacement; (2) estimate the amount of time before room closure would be expected to transfer rock loads to the waste packages. The work consisted of (1) an analysis of geotechnical data and a review of the Department of Energy`s (DOE) plans for waste emplacement in panel 1, (2) an evaluation of ground conditions based on data analysis and observations of changes in ground conditions since the first evaluation in 1993 (USBM 1993), and (3) preparation of a report and presentation of the results to EEG staff. Excluded from this study are radiological safety issues and policies. The study is based on data provided by DOE and Westinghouse Electric Corporation (operator of the site) and conversations with DOE and Westinghouse personnel. MTI cannot independently verify the accuracy of the data within the scope of this study and recommends independent evaluations of data gathering, quality assurance procedures, and structural designs. The operator has the ultimate responsibility for structural designs and has expressed a strong commitment to ensuring worker safety.

  6. Evaluation of solidification/stabilization technology for Buffalo River sediment. Final report

    SciTech Connect

    Fleming, E.C.; Averett, D.E.; Channell, M.G.; Perry, B.D.

    1991-05-01

    The Buffalo River drains a 446-square-mile (1,155-sq-km) watershed in western New York State and discharges into Lake Erie at the city of Buffalo. The Buffalo River has been classified by the State of New York as a fishing and fish survival stream, but municipal and industrial discharges have degraded the water quality and resulted in a fish advisory for the river. Under the Assessment and Remediation of Contaminated Sediment Program, the US Environmental Protection Agency asked the US Army Corps of Engineers to evaluate solidification/stabilization (S/S) for potential treatment of the contaminated sediments in the Buffalo River. An evaluation of S/S technology was conducted on the bench-scale level on Buffalo River sediment to determine whether physical and chemical properties of the sediment would be improved. Based on analyses of the untreated sediment, five metals were selected for evaluation: chromium, copper, lead, nickel, and zinc. Initial screening tests (ISTs) were conducted on the sediments to narrow the range of binder-to-soil ratios (BSRs) to be prepared in the detailed evaluation.

  7. Re-evaluating the role of sterics and electronic coupling in determining the open-circuit voltage of organic solar cells.

    PubMed

    Graham, Kenneth R; Erwin, Patrick; Nordlund, Dennis; Vandewal, Koen; Li, Ruipeng; Ngongang Ndjawa, Guy O; Hoke, Eric T; Salleo, Alberto; Thompson, Mark E; McGehee, Michael D; Amassian, Aram

    2013-11-13

    The effects of sterics and molecular orientation on the open-circuit voltage and absorbance properties of charge-transfer states are explored in model bilayer organic photovoltaics. It is shown that the open-circuit voltage correlates linearly with the charge-transfer state energy and is not significantly influenced by electronic coupling. PMID:23897581

  8. Evaluation of Antioxidant Stability of Arbutin and Pyrus boissieriana Buhse Leaf Extract

    PubMed Central

    Khalilpour, Asieh; Pouramir, Mahdi; Asgharpour, Fariba

    2013-01-01

    With regard to the importance of antioxidants in foods, cosmetics and pharmaceutics, there are several studies on natural resources for finding rich sources of antioxidants and their role in protecting the body against oxidative stress injuries. The purpose of this study was to investigate the antioxidant stability of arbutin and the Pyrus boissieriana buhse Leaf extract and their effects on lipid oxidation in different conditions of temperature and time. Arbutin and the Pyrus boissieriana buhse Leaf extract were stored for 14 days in the different conditions of temperature including room, refrigerator and freezer. Total phenolic compounds were measured by the folin-ciocaltea method. Flavonoid compounds were evaluated by aluminum chloride method. Their total antioxidant activity was measured by FRAP (ferric reducing antioxidant power) method and their protection effect on lipid oxidation was measured by TBARS (thiobarbituric acid reactant substances) method. Also, the amount of sustainability for peroxide activities was measured by TMB (Tetra Methyl Benzedrine) method. Polyphenol formed 1.96 mg/g dry weight of Pyrus boissieriana buhse Leaf extract and the amount of flavonoid complex was 0.125 mg/g dry weight of Pyrus boissieriana buhse Leaf extract. The amount of FRAP was decreased by increasing temperature and time. The amount of lipid oxidation had increased in all samples with time (0-14). The stability of peroxide activities decreased in the different conditions of temperature and time. The results of this study show the existence of antioxidant activities with higher stability in storage time and the protective effect of arbutin and Pyrus boissieriana buhse Leaf extract on lipid oxidation. Therefore, using arbutin and Pyrus boissieriana buhse Leaf extract as a natural resource of antioxidant is suggested for substituting synthetic antioxidants. PMID:24551796

  9. 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.

  10. Evaluation of the effectiveness of various amendments on trace metals stabilization by chemical and biological methods.

    PubMed

    Lee, Sang-Hwan; Park, Hyun; Koo, Namin; Hyun, Seunghun; Hwang, Anna

    2011-04-15

    We evaluated the effects of five different kinds of amendments on heavy metals stabilization. The five amendments were: zero valent iron, limestone, acid mine drainage treatment sludge, bone mill, and bottom ash. To determine bioavailability of the heavy metals, different chemical extraction procedures were used such as, extraction with (Ca(NO(3))(2), DTPA; toxic characteristic leaching procedure (TCLP), physiologically based extraction test (PBET) that simulates gastric juice, and sequential extraction test. Bioavailability was also determined by measuring uptake of the heavy metals by lettuce (Lactuca sativa L.) and earthworms (Eisenia fetida). In addition, dehydrogenase activity was measured to determine microbial activity in the soil with the different amendments. The addition of amendments, especially limestone and bottom ash, resulted in a significant reduction in extractable metal contents. Biological assays using lettuce, earthworm, and enzyme activity were found as appropriate indicators of available metal fraction after in situ stabilization of heavy metals. In conclusion, TCLP and sequential extraction test appear to be promising surrogate measure of metal bioavailability in soils for several environment endpoints. PMID:21333442

  11. 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.

  12. Evaluation of toxic and genotoxic potential of stabilized industrial waste and contaminated soils.

    PubMed

    Békaert, C; Ferrier, V; Marty, J; Pfohl-Leszkowicz, A; Bispo, A; Jourdain, M J; Jauzein, M; Lambolez-Michel, L; Billard, H

    2002-01-01

    Artificial aqueous samples (eluates, percolates, immersion waters) were obtained from contaminated soils and stabilized industrial wastes. The toxicity and genotoxicity of these aqueous fractions have been evaluated in vivo in the aquatic larvae of the amphibian Xenopus laevis. Four biotests have been applied: a test of subchronic toxicity and three biomakers: (1) measurement of the activity of ethoxyresorufine-o-dealkylase in the liver, (2) detection of DNA adducts in the liver and the blood, and (3) measurement of the rate of micronuclei in the erythrocytes. Biological datas were completed through a chemical analysis. The main conclusions of this study are: The importance of integrating different toxicity criterias into a biological battery (phenotypic and genotypic criterias). Some aqueous extracts did not seem to be very toxic, whereas their genotoxic effects were rather significant [e.g. the stabilized Municipal Solid Waste (MSW) ashes]. The importance of coupling together chemical and biological approaches to refine the impact. Actually, some eluates (lixiviation or percolation) coming from polluted soils appeared to be very poorly loaded with pollutants, whereas the toxic and genotoxic impact of these complex matrices were rather noticeable. In addition, when applying the leaching standardized procedure, the hazardous potential of the two analysed soils may be underestimated if the results on percolates and on eluates have been compared. This study highligths the importance of coupling the tools of characterization and preparation of samples to be analysed according to the objectives to be reached. PMID:12003154

  13. Stability and biological activity evaluations of PEGylated human basic fibroblast growth factor

    PubMed Central

    Hadadian, Shahin; Shamassebi, Dariush Norouzian; Mirzahoseini, Hasan; Shokrgozar, Mohamad Ali; Bouzari, Saeid; Sepahi, Mina

    2015-01-01

    Background: Human basic fibroblast growth factor (hBFGF) is a heparin-binding growth factor and stimulates the proliferation of a wide variety of cells and tissues causing survival properties and its stability and biological activity improvements have received much attention. Materials and Methods: In the present work, hBFGF produced by engineered Escherichia coli and purified by cation exchange and heparin affinity chromatography, was PEGylated under appropriate condition employing 10 kD polyethylene glycol. The PEGylated form was separated by size exclusion chromatography. Structural, biological activity, and stability evaluations were performed using Fourier transform infrared (FITR) spectroscopy, 3-(4,5-dimethylthiazol-2yl)-2,5-diphenyltetrazolium bromide (MTT) assay and effect denaturing agent, respectively. Results: FITR spectroscopy revealed that both PEGylated and native forms had the same structures. MTT assay showed that PEGyalated form had a 30% reduced biological activity. Fluorescence spectrophotometry indicated that the PEGylated form denatured at higher concentrations of guanidine HCl (1.2 M) compared with native, which denatured at 0.8 M guanidine HCl. Conclusions: PEGylation of hBFGF makes it more stable against denaturing agent but reduces its bioactivity up to 30%. PMID:26605215

  14. Stability evaluation of temoporfin-loaded liposomal gels for topical application.

    PubMed

    Dragicevic-Curic, Nina; Winter, Sven; Krajisnik, Danina; Stupar, Mirjana; Milic, Jela; Graefe, Susanna; Fahr, Alfred

    2010-03-01

    Temoporfin (mTHPC) is a potent second-generation synthetic photosensitizer. Topical delivery of mTHPC is of great interest for the photodynamic therapy of psoriasis and superficial skin cancer lesions. The aim of this study was to evaluate the stability of hydrophilic gels containing mTHPC-loaded liposomes. Two different mTHPC-loaded liposome dispersions, composed of 15 % (w/w) nonhydrogenated soybean lecithin of different phosphatidylcholine content, were prepared and incorporated (2:1 w/w) into hydrogels of different carbomer concentrations (1.5, 2.25, and 3%; w/w). Obtained liposomal hydrogels, containing 0.15% (w/w) mTHPC, 10% (w/w) phospholipids, and 0, 0.5, or 1% (w/w) carbomer, were analyzed for flow properties, liposome particle size, and polydispersity index (PDI), pH value, and mTHPC content after their preparation and at predetermined time intervals during 6 months of storage at 4 and 23 degrees C. All hydrogels showed, during the whole period of investigation, adequate characteristics for topical application (i.e., they revealed shear-thinning plastic flow behavior). Rheological parameters, particle size, and PDI of liposomes in hydrogels, mTHPC content, and pH value did not show remarkable changes during the storage of gels, which could make them unacceptable for topical use. The obtained results indicated physical and chemical stability of liposomal gels containing mTHPC during 6 months of storage at both temperatures. PMID:19558347

  15. 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.

  16. 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.

  17. Using in-process measurements of open-gate structures to evaluate threshold voltage of normally-off GaN-based high electron mobility transistors

    NASA Astrophysics Data System (ADS)

    Hou, Bin; Ma, Xiao-Hua; Chen, Wei-Wei; Zhu, Jie-Jie; Zhao, Sheng-Lei; Chen, Yong-He; Xie, Yong; Zhang, Jin-Cheng; Hao, Yue

    2015-10-01

    The parameters of open-gate structures treated with different etching time were monitored during the gate recess process, and their impacts on the threshold voltage (Vth) of final fabricated AlGaN/GaN high electron mobility transistors (HEMTs) based on open-gate structures were discussed in this paper. It is found that Vth can exceed 0 V when channel resistance in the recessed region (Ron-open) increases over ˜275 ? mm, maximum current (IDmax) decreases below ˜29 mA/mm, or recessed barrier thickness (tRB) is below ˜7.5 nm. In addition, tRB obtained by atomic force microscopy measurements and C-V measurements are also compared. Finally, theoretical common criteria based on the experimental results of this work for tRB and Ron-open were established to evaluate the Vth of a regular normally-off AlGaN/GaN HEMTs. The results indicate that these parameters of open-gate structure can be utilized to achieve normally-off HEMTs with controllable Vth.

  18. Unique correlation between non-linear distortion of tangential magnetic field and magnetic excitation voltage - Unexplored ferromagnetic phenomena and their application for ferromagnetic materials evaluation

    NASA Astrophysics Data System (ADS)

    Moorthy, V.

    2016-01-01

    Unexplored ferromagnetic phenomena of non-linear distortion of tangential magnetic field (HT) and that of excitation voltage (VE) across the electromagnetic (EM) yoke, in the presence of a ferromagnetic material between the poles of the EM yoke, have been uniquely correlated in this study. Both the HT and VE show similar distortion behaviour, but in the opposite direction, with unique shape for each ferromagnetic sample with different microstructural conditions. Interestingly unique correlation between (dVE / dt) and (dHT / dt) profiles and their ability to distinguish different magnetisation behaviour of ferromagnetic material with different microstructures have also been discussed in this study. One to one correlation between the distortion of HT and VE shown in this study is clear evidence that both these parameters are strongly influenced by the same mechanism of magnetisation process, but in different ways. The systematic changes in the height and position of the peak and the trough on the time derivative profiles of VE and HT reflect the subtle differences in the magnetisation process for each microstructural condition of the steel. This study reveals the new scientific insight and good potential of this novel as well as very simple approach of distortion analysis of HT and VE for understanding the influence of material properties on the mechanism of magnetisation process and also their suitability for variety of applications related to materials evaluation of ferromagnetic components and structures.

  19. Use of a general control simulation program to evaluate HVAC control stability

    NASA Astrophysics Data System (ADS)

    Zhang, Xinbang; Warren, M. L.

    1987-08-01

    A general process engineering simulation program for a microcomputer is used to evaluate the response of a cooling system to changes in load, set point, and controller tuning parameters to better understand the control stability of a supply air cooling system used in the Mobile Windows Thermal Test (MoWiTT) Facility. A detailed system model is built out of standard components and is used to plot the steady state performance under different operating conditions. The response of the cooling coil output depends strongly on the transport delays. For a system with a linear control valve, the process gain of the cooling coil increases rapidly as the valve flow fraction decreases. A system which is stable at mid-range is shown to become marginally unstable at the low end of the control range. The application of both an equal percentage valve and reheat are shown to improve the control response of the system under low cooling load conditions.

  20. Validity and Reliability of Limits-of-Stability Testing: A Comparison of 2 Postural Stability Evaluation Devices

    PubMed Central

    Pickerill, Marie L.; Harter, Rod A.

    2011-01-01

    Context: A lack of published comparisons between measures from commercially available computerized posturography devices and the outcome measures used to define the limits of stability (LOS) makes meaningful interpretation of dynamic postural stability measures difficult. Objectives: To compare postural stability measures between and within devices to establish concurrent and construct validity and to determine test-retest reliability for LOS measures generated by the NeuroCom Smart Balance Master and the Biodex Balance System. Design: Cross-sectional study. Setting: Controlled research laboratory. Patients or Other Participants: A total of 23 healthy participants with no vestibular or visual disabilities or lower limb impairments. Intervention(s): The LOS were assessed during 2 laboratory test sessions 1 week apart. Main Outcome Measure(s): Three NeuroCom LOS variables (directional control, endpoint excursion, and movement velocity) and 2 Biodex LOS variables (directional control, test duration). Results: Test-retest reliability ranged from high to low across the 5 LOS measures (intraclass correlation coefficient [2,k] = 0.82 to 0.48). Pearson correlations revealed 4 significant relationships (P < .05) between and within the 2 computerized posturography devices (r = 0.42 to ?0.65). Conclusions: Based on the wide range of intraclass correlation values we observed for the NeuroCom measures, clinicians and researchers alike should establish the reliability of LOS testing for their own clinics and laboratories. The low to moderate reliability outcomes observed for the Biodex measures were not of sufficient magnitude for us to recommend using the LOS measures from this system as the gold standard. The moderate Pearson interclass correlations we observed suggest that the Biodex and NeuroCom postural stability systems provided unique information. In this study of healthy participants, the concurrent and construct validity of the Biodex and NeuroCom LOS tests were not definitively established. We recommend that this study be repeated with a clinical population to further explore the matter. PMID:22488184

  1. Evaluation of the stability of a nanoremediation strategy using barley plants.

    PubMed

    Gil-Díaz, M; González, A; Alonso, J; Lobo, M C

    2016-01-01

    This study evaluated the effectiveness of nZVI in reducing the availability of Cd, Cr or Zn in polluted soils. The influence of this nanoremediation process on the development of barley plants as well as its impact on soil properties and the stability of the metal immobilization afterwards were also evaluated in a greenhouse experiment. The application of nZVI reduced the availability of these metals in the soil, but the effectiveness of the immobilization and its stability depended on the metal chemical characteristics. Cadmium distribution in soil fractions showed an important change after the barley crop, favoring the immobilization of Cd in RS fraction for both nZVI-treated and untreated soils. The Cr immobilization was stable over the time studied and the doses of Cr were lethal for the barley plants. In contrast, the decrease of Cr availability reached after the nZVI treatment induced a reduction of soil phytotoxicity and an improvement in the development of the plants, which were able to complete their growing period. The Zn immobilization with nZVI was stable over time, but its effectiveness was moderate, and the growth of barley plants was poorer than that observed in the cases of Cd and Cr. Thus the best results of metal immobilization with nZVI were obtained for Cr-polluted soils. There was no overall increase of Fe in barley plants from nZVI-treated soils. In relation to the soil, no negative effects on its physico-chemical properties were observed after the time exposure with nZVI. Taking into account these results we can conclude that the use of nZVI is a promising remediation strategy, and its effectiveness would be conditioned to the soil properties and the bioavailable metal concentration. PMID:26431642

  2. 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.; Nagpure, I.M.; Kumar, Vinay; Ntwaeaborwa, O.M.; Terblans, J.J.; Swart, H.C.

    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.

  3. 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.

  4. AC system stability analysis and assessment for Shipboard Power Systems 

    E-print Network

    Qi, Li

    2006-04-12

    due to reconfiguration might cause voltage instability, such as progressive voltage decreases or voltage oscillations. SPS stability thus should be assessed to ensure the stable operation of a system during reconfiguration. In this dissertation, time...

  5. Voltage-gated sodium channels

    PubMed Central

    Abdelsayed, Mena; Sokolov, Stanislav

    2013-01-01

    Epilepsy is a brain disorder characterized by seizures and convulsions. The basis of epilepsy is an increase in neuronal excitability that, in some cases, may be caused by functional defects in neuronal voltage gated sodium channels, Nav1.1 and Nav1.2. The effects of antiepileptic drugs (AEDs) as effective therapies for epilepsy have been characterized by extensive research. Most of the classic AEDs targeting Nav share a common mechanism of action by stabilizing the channel’s fast-inactivated state. In contrast, novel AEDs, such as lacosamide, stabilize the slow-inactivated state in neuronal Nav1.1 and Nav1.7 isoforms. This paper reviews the different mechanisms by which this stabilization occurs to determine new methods for treatment. PMID:23531742

  6. Evaluation of extra virgin olive oil stability by artificial neural network.

    PubMed

    Silva, Simone Faria; Anjos, Carlos Alberto Rodrigues; Cavalcanti, Rodrigo Nunes; Celeghini, Renata Maria dos Santos

    2015-07-15

    The stability of extra virgin olive oil in polyethylene terephthalate bottles and tinplate cans stored for 6 months under dark and light conditions was evaluated. The following analyses were carried out: free fatty acids, peroxide value, specific extinction at 232 and 270 nm, chlorophyll, L(?)C(?)h color, total phenolic compounds, tocopherols and squalene. The physicochemical changes were evaluated by artificial neural network (ANN) modeling with respect to light exposure conditions and packaging material. The optimized ANN structure consists of 11 input neurons, 18 hidden neurons and 5 output neurons using hyperbolic tangent and softmax activation functions in hidden and output layers, respectively. The five output neurons correspond to five possible classifications according to packaging material (PET amber, PET transparent and tinplate can) and light exposure (dark and light storage). The predicted physicochemical changes agreed very well with the experimental data showing high classification accuracy for test (>90%) and training set (>85). Sensitivity analysis showed that free fatty acid content, peroxide value, L(?)Cab(?)hab(?) color parameters, tocopherol and chlorophyll contents were the physicochemical attributes with the most discriminative power. PMID:25722136

  7. Evaluating the efficiency of an asbestos stabilizer on ceiling tiles and the characteristics of the released asbestos fibers.

    PubMed

    Jung, Hyun-Sung; Cha, Jun-Seok; Kim, Seongmi; Lee, Wooseok; Lim, Ho-Ju; Kim, Hyunwook

    2015-12-30

    The efficiency of asbestos stabilizers and their adaptability were evaluated by investigating the characteristics of asbestos fibers released from ceiling tiles. The impact of such variables as the wind speed or vibration conditions was also studied along with the asbestos stabilizers. The concentrations of the asbestos fibers released from damaged ceiling tiles treated with stabilizers decreased by 69.5-84.4% compared with those of untreated tiles for all variables, with a statistically significant difference (p<0.001). The effects of the environmental factors on the asbestos concentrations were analyzed through a multiple regression analysis. It was determined that the surface status of the ceiling tiles and stabilizers were the main factors affecting the concentration, and the reliability of these factors was estimated as 58.3%. The lengths of the chrysotile fibers released from the damaged ceiling tiles were in the range of 0.991-79.1?m for the untreated tiles and 3.74-35.6?m for the tiles treated with inorganic stabilizers. It was confirmed that inorganic stabilizers are more efficient for damaged ceiling tiles. The results of this study also show that the asbestos concentrations are greatly reduced after treating damaged ceiling tiles with a stabilizer. PMID:26218305

  8. Formulation and stability evaluation of extemporaneously prepared atenolol capsules from crushed atenolol tablets.

    PubMed

    Zaid, Abdel Naser; Malkieh, Numan; Kharoaf, Maher; Abu Ghoush, Abeer; Al-Ramahi, Rowa'

    2012-01-01

    The purpose of this study was to formulate a 25-mg atenolol capsule starting from a commercial 100-mg atenolol tablet, given the fact that this strength is not available in Palestine and also because 50-mg atenolol tablets failed the splitting uniformity test of the European Pharmacopoeia, and to evaluate the chemical stability and dissolution behavior of the obtained capsules so as to ensure a high-quality product. A high-performance liquid chromatographic system was used for the analysis and quantification of atenolol in the samples studied. Samples of atenoIol for analysis were prepared as reported by the United States Pharmacopeia monograph. Disintegration and dissolution tests were performed according to the United States Pharmacopeia. The high-performance liquid chromatography assay indicated that the 25-mg atenolol capsules were stable for four months when stored at ambient temperature conditions. The disintegration time for all atenolol capsules was within the United States Pharmacopeia limits of 15 minutes. Atenolol release profile showed that approximately 90% of atenolol dissolved after 10 minutes. This study is important for patients who need to take one half of a 50-mg tablet, but for whom the splitting process doesn't give equal halves, and also for modifying the dose for patients with renal or hepatic problems. Therefore, it is possible for the community pharmacist to crush atenolol 100-mg tablets and refill them in new capsules with each containing a precise amount of atenolol, calculated according to body surface area and kidney and liver functions without affecting the chemical stability of the active ingredient nor its dissolution profile and also have a cost effective dosage form. PMID:23050394

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

    PubMed

    Cheng, Lei; Hannaford, Blake

    2016-01-01

    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

  10. Automatic voltage imbalance detector

    DOEpatents

    Bobbett, Ronald E. (Los Alamos, NM); McCormick, J. Byron (Los Alamos, NM); Kerwin, William J. (Tucson, AZ)

    1984-01-01

    A device for indicating and preventing damage to voltage cells such as galvanic cells and fuel cells connected in series by detecting sequential voltages and comparing these voltages to adjacent voltage cells. The device is implemented by using operational amplifiers and switching circuitry is provided by transistors. The device can be utilized in battery powered electric vehicles to prevent galvanic cell damage and also in series connected fuel cells to prevent fuel cell damage.

  11. 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...

  12. 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...

  13. 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

  14. Optimization of power systems with voltage security constraints

    NASA Astrophysics Data System (ADS)

    Rosehart, William Daniel

    As open access market principles are applied to power systems, significant changes in their operation and control are occurring. In the new marketplace, power systems are operating under higher loading conditions as market influences demand greater attention to operating cost versus stability margins. Since stability continues to be a basic requirement in the operation of any power system, new tools are being considered to analyze the effect of stability on the operating cost of the system, so that system stability can be incorporated into the costs of operating the system. In this thesis, new optimal power flow (OPF) formulations are proposed based on multi-objective methodologies to optimize active and reactive power dispatch while maximizing voltage security in power systems. The effects of minimizing operating costs, minimizing reactive power generation and/or maximizing voltage stability margins are analyzed. Results obtained using the proposed Voltage Stability Constrained OPF formulations are compared and analyzed to suggest possible ways of costing voltage security in power systems. When considering voltage stability margins the importance of system modeling becomes critical, since it has been demonstrated, based on bifurcation analysis, that modeling can have a significant effect of the behavior of power systems, especially at high loading levels. Therefore, this thesis also examines the effects of detailed generator models and several exponential load models. Furthermore, because of its influence on voltage stability, a Static Var Compensator model is also incorporated into the optimization problems.

  15. Aalborg Universitet Secondary Frequency and Voltage Control of Islanded Microgrids via Distributed

    E-print Network

    Vasquez, Juan Carlos

    we present new distributed controllers for secondary frequency and voltage control in islanded micro- grids. Inspired by techniques from cooperative control, the pro- posed controllers use localized provide a voltage stability analysis and present extensive experimental results validating our designs

  16. Incorporating voltage security into the planning, operation and monitoring of restructured electric energy markets 

    E-print Network

    Nair, Nirmal-Kumar

    2006-04-12

    state voltage stability index to detect potential dynamic voltage collapse. Finally, this dissertation examines developments in representation, standardization, communication and exchange of power system data. Power system data is the key input to all...

  17. High Voltage SPT Performance

    NASA Technical Reports Server (NTRS)

    Manzella, David; Jacobson, David; Jankovsky, Robert

    2001-01-01

    A 2.3 kW stationary plasma thruster designed to operate at high voltage was tested at discharge voltages between 300 and 1250 V. Discharge specific impulses between 1600 and 3700 sec were demonstrated with thrust between 40 and 145 mN. Test data indicated that discharge voltage can be optimized for maximum discharge efficiency. The optimum discharge voltage was between 500 and 700 V for the various anode mass flow rates considered. The effect of operating voltage on optimal magnet field strength was investigated. The effect of cathode flow rate on thruster efficiency was considered for an 800 V discharge.

  18. Hyphenation of a Deoxyribonuclease I immobilized enzyme reactor with liquid chromatography for the online stability evaluation of oligonucleotides.

    PubMed

    Álvarez Porebski, Piotr Wiktor; Gyssels, Ellen; Madder, Annemieke; Lynen, Frederic

    2015-11-27

    The stability of antisense oligonucleotides (ONs) toward nucleases is a key aspect for their possible implementation as therapeutic agents. Typically, ON stability studies are performed off-line, where the ONs are incubated with nucleases in solution, followed by their analysis. The problematics of off-line processing render the detailed comparison of relative ON stability quite challenging. Therefore, the development of an online platform based on an immobilized enzyme reactor (IMER) coupled to liquid chromatography (LC) was developed as an alternative for improved ON stability testing. More in detail, Deoxyribonuclease I (DNase I) was immobilized on epoxy-silica particles of different pore sizes and packed into a column for the construction of an IMER. Subsequently, the hyphenation of the IMER with ion-pair chromatography (IPC) and ion-exchange chromatography (IEC) was evaluated, leading to the successful development of two online methodologies: IMER-IPC and IMER-IEC. More specifically, natural and modified DNA and RNA oligonucleotides were used for testing the performance of the methodologies. Both methodologies proved to be simple, automatable, fast and highly reproducible for the quantitative and qualitative evaluation of ON degradation. In addition, the extended IMER life time in combination with a more straightforward control of the reaction kinetics substantiate the applicability of the IMER-LC platform for ON stability tests and its implementation in routine and research laboratories. PMID:26515385

  19. Preparation of sterically stabilized chitin nanowhisker dispersions by grafting of poly(ethylene glycol) and evaluation of their dispersion stability.

    PubMed

    Araki, Jun; Kurihara, Mari

    2015-01-12

    Sterically stabilized chitin nanowhiskers (ChNWs) were prepared by surface grafting monomethoxy poly(ethylene glycol) (mPEG) via reductive amination of primary amino groups on ChNWs and terminal aldehydes on mPEG. The amount of grafted mPEG was determined to be 0.2-0.3 g/g ChNWs, by conductometric titration, from the decrease in amino groups after grafting. ChNWs with controlled amounts of surface amino groups were obtained by deacetylation; however, this did not cause a drastic change in the amount of grafted mPEG. Grafting was confirmed by Fourier-transform infrared spectroscopy; however, X-ray diffractometry indicated no sign of mPEG. Thermogravimetry indicated a higher amount of mPEG than that from titration, suggesting an overestimation due to the facilitated combustion of grafted samples. In contrast to ungrafted samples, all grafted samples were stable in the presence of electrolytes. However, liquid-crystalline phase separation of grafted ChNWs was not observed, possibly owing to the high viscosity of the concentrated sample. PMID:25455958

  20. BICUVOX.1-matrix composite electrolyte with yttria-stabilized zirconia as an inert phase: SEM evaluation of the chemical stability under hydrogen atmosphere.

    PubMed

    Piva, R H; Piva, D H; Venturini, J; Floriano, R; Morelli, M R

    2015-09-01

    The purpose of this study is to evaluate the efficacy of yttria-stabilized zirconia (3Y-TZP) as an inert phase to prevent the decomposition of Bi2 V0.9 Cu0.1 O5.5 -? (BICUVOX.1) electrolyte under reducing atmosphere. A post-mortem scanning electron microscopy (SEM) study was performed after chemical stability tests under hydrogen-rich atmosphere using a Sieverts-type apparatus. SEM results showed that BICUVOX.1 decomposition starts under a hydrogen pressure of 19.7?atm at 300°C, even in the case of the composite containing 3Y-TZP. The microstructure of BICUVOX.1 after decomposition was observed to be composed of microspheres ranging from 10 to 100?µm formed primarily of metallic bismuth. In the composite, in addition to microspheres, the microstructure contained bismuth fibers growth from the grain area of the BICUVOX.1 matrix. Despite significant surface morphological modifications, the grain-boundary-arranged 3Y-TZP particles in a BICUVOX.1-matrix composite did not result in enhanced chemical stability. SCANNING 37:372-379, 2015. © 2015 Wiley Periodicals, Inc. PMID:25940790

  1. Array-level stability enhancement of 50 nm AlxOy ReRAM

    NASA Astrophysics Data System (ADS)

    Iwasaki, Tomoko Ogura; Ning, Sheyang; Yamazawa, Hiroki; Takeuchi, Ken

    2015-12-01

    ReRAM's low voltage and low current programmability are attractive features to solve the scaling issues of conventional floating gate Flash. However, read instability in ReRAM is a critical issue, due to random telegraph noise (RTN), sensitivity to disturb and retention. In this work, the array-level characteristics of read stability in 50 nm AlxOy ReRAM are investigated and a circuit technique to improve stability is proposed and evaluated. First, in order to quantitatively assess memory cell stability, a method of stability characterization is defined. Next, based on this methodology, a proposal to improve read stability, called "stability check loop" is evaluated. The stability check loop is a stability verification procedure, by which, instability improvement of 7×, and read error rate improvement of 40% are obtained.

  2. Evaluation of the thermal stability POHC incinerability ranking in a pilot-scale rotary kiln incinerator

    SciTech Connect

    Lee, J.W.; Waterland, L.R.; Whitworth, W.E.; Carroll, G.J.

    1991-01-01

    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 POHCs with predicted incinerability spanning the range of most to least difficult to incinerate class were combined with a clay-based sorbent and batch-fed to the facility's pilot-scale rotary kiln incinerator via a fiberpack drum ram feeder. Kiln operating conditions were varied to include a baseline operating condition, three modes of attempted incineration failure, and a worst case combination of the three failure modes. Kiln exit POHC DREs were in the 99.99 percent range for the volatile POHCs for the baseline, mixing failure (increased charge mass), and matrix failure (decreased feed H/C) tests. Semivolatile POHCs were not detected in the kiln exit for these tests; corresponding DREs were generally greater than 99.999 percent. The thermal failure (low kiln temperature) and worst case (combination of thermal, mixing, and matrix failure) tests resulted in substantially decreased kiln exit POHC DREs. These ranged from 99 percent or less for Freon 113 to greater than 99.999 percent for the less stable-ranked semivolatile POHCs. General agreement between relative kiln exit POHC DRE and predicted incinerability class was observed.

  3. Pilot-scale evaluation of the thermal-stability POHC incinerability anking

    SciTech Connect

    Lee, J.W.; Whitworth, W.E.; Waterland, L.R.

    1992-04-01

    A test series were performed at the U.S. EPA Incineration Research Facility (IRF) to evaluate the thermal-stability-based principal organic hazardous constituent (POHC) incinerability ranking. Mixtures of twelve POHCs with predicted incinerabilities spanning the range of most- to least-difficult-to-incinerate classes were combined with a clay-based sorbent matrix and fed to the facility's pilot-scale rotary kiln incinerator. Kiln operating conditions were varied to include a baseline operating condition, three modes of attempted incineration failure, and a worst-case combination of the three failure modes. Kiln-exit POHC destruction and removal efficiencies (DREs) were in the 99.99% range for the volatile POHCs during the baseline, mixing failure and matrix failure tests. Semivolatile POHCs were not detected at the kiln exit for these tests; corresponding DREs were generally greater than 99.999%. The thermal failure and worst-case tests resulted in substantially decreased kiln-exit POHC DREs, ranging from less than 99% to greater than 99.999%. General agreement between measured and predicted relative kiln-exit POHC DREs was observed for those two tests.

  4. Comparison of methods for evaluating the thermal stability of human enteric viruses.

    PubMed

    Arthur, Sabastine E; Gibson, Kristen E

    2015-03-01

    Human enteric viruses have been identified as one of the predominant causative agents of food-borne illnesses in developed countries, and it is estimated that human norovirus accounts for a majority of these illnesses each year. Not all of these viruses can be cultured and hence relatively little is known about their pathogenesis and physicochemical properties. To overcome this, researchers have utilized different virus surrogates for the study of non-cultivable human enteric viruses. In this review, we discuss various methods utilized for the evaluation of the thermal stability of human enteric viruses, compare the results of these methods, and examine how researchers may move toward a single standard approach (i.e., temperatures, virus concentrations, volume/weight of matrices, etc.) for determining thermal inactivation profiles of human enteric viruses and their surrogates. Based on our review, we found that temperature, time of exposure, type of matrix, analysis type, type of heat application, and the concentration and volume of virus used in the experiments were highly variable across virus surrogates even for the same surrogates. Because of these differences-along with the inherent limitations of using surrogate viruses-comparison of these methods and how the results may be extrapolated to human enteric viruses is quite challenging. As a result, we discuss how researchers may move toward a single standard approach for determining thermal inactivation profiles of human enteric viruses and their surrogates. PMID:25526719

  5. Evaluation of infectious bursal disease virus stability at different conditions of temperature and pH.

    PubMed

    Rani, Surabhi; Kumar, Sachin

    2015-11-01

    Infectious bursal disease (IBD) is one of the highly pathogenic viral diseases of poultry. The disease poses a serious threat to the economy of many developing countries where agriculture serves as the primary source of national income. Infectious bursal disease virus (IBDV) belongs to the family Birnaviridae. The IBDV is well characterized to cause immunosuppression in poultry. The live attenuated vaccine is the only way to protect the chickens from IBDV infection. The ineffectiveness of vaccine is one of the major causes of IBDV outbreaks in field condition. In the present study, we discuss briefly about the biology of IBDV genome and its proteins under different conditions of temperature and pH in order to evaluate its infectivity under adverse physical conditions. Our results indicate that the IBDV is non-infective above 42 °C and unstable above 72 °C. However, the change in pH does not significantly contribute to the IBDV stability. The study will be useful in estimating an optimum storage condition for IBDV vaccines without causing any deterioration in its viability and effectiveness. PMID:26265229

  6. Experimental evaluation of Harrington rod fixation supplemented with sublaminar wires in stabilizing thoracolumbar fracture-dislocations.

    PubMed

    Munson, G; Satterlee, C; Hammond, S; Betten, R; Gaines, R W

    1984-10-01

    Segments of the spinal column of calves were instrumented with Harrington rods with and without sublaminar wires. Grossly unstable lesions were created by resecting a 2-cm segment from the central spinal segment. Testing on an Instron tester documented the improvement in stability provided by the sublaminar wires in this grossly unstable experimental fracture. Improved stability was seen in resisting axial loading, lateral bending, and forward flexion loading. Rotational stability was particularly improved. PMID:6478708

  7. Interfacial degradation effects of aqueous solution-processed molybdenum trioxides on the stability of organic solar cells evaluated by a differential method

    SciTech Connect

    Lou, Yan-Hui; Wang, Zhao-Kui E-mail: lsliao@suda.edu.cn; Yuan, Da-Xing; Liao, Liang-Sheng E-mail: lsliao@suda.edu.cn; Okada, Hiroyuki

    2014-09-15

    The authors investigate the influence of two hole interfacial materials poly (3,4-ethylenedioxythiophene):poly (styrenesulfonate) (PEDOT:PSS) and aqueous solution-processed MoO{sub 3} (sMoO{sub 3}) on cell stability. sMoO{sub 3}-based device demonstrated obviously improved stability compared to PEDOT:PSS-based one. Current-voltage characteristics analysis is carried out to investigate the effect of the hole interfacial layers on the cell stability. The formation of additional trap states at the interfaces between the hole interfacial layer and the active layer in degraded devices is verified by a differential method. Improved cell stability is attributed to a relatively stable sMoO{sub 3} interfacial layer compared to PEDOT:PSS by comparing their different trap states distributions.

  8. NODE VOLTAGE DEPENDENT SUBTHRESHOLD LEAKAGE CURRENT CHARACTERISTICS OF DYNAMIC CIRCUITS

    E-print Network

    Friedman, Eby G.

    NODE VOLTAGE DEPENDENT SUBTHRESHOLD LEAKAGE CURRENT CHARACTERISTICS OF DYNAMIC CIRCUITS Volkan circuits is evaluated in this paper. The strong dependence of the subthreshold leakage current on the node voltages is discussed. In a standard low threshold voltage domino logic circuit with stacked pull- down

  9. 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.

  10. 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.

  11. Study of second phase in bioabsorbable magnesium alloys: Phase stability evaluation via Dmol{sup 3} calculation

    SciTech Connect

    Yang, Huazhe; Liu, Chen; Wan, Peng; Tan, Lili; Yang, Ke

    2013-11-01

    Thermodynamical stabilities of four conventional second phases as well as magnesium matrix in bioabsorbable magnesium alloys were investigated theoretically via computer calculation method. Model of individual phase and systems including phase and four water molecular (phase-4H{sub 2}O) were established to simulate the in vitro and in vivo environment. Local orbital density functional theory approach was applied to calculate the total energy for the individual phase and phase-4H{sub 2}O system. The results demonstrated that all the second phases possessed higher phase stability compared with magnesium matrix, but the phase stability was quite different for different types of second phases or second phase-4H{sub 2}O systems. Furthermore, a schematic process of inflammation reaction caused by magnesium alloy implants was proposed for the further evaluation on biocompatibility of different second phases.

  12. Mass spectrometric evaluation of neuropeptidomic profiles upon heat stabilization treatment of neuroendocrine tissues in crustaceans

    PubMed Central

    Sturm, Robert M.; Greer, Tyler; Woodards, Nicole; Gemperline, Erin; Li, Lingjun

    2012-01-01

    Tissue heat stabilization is a vital component in successful mammalian neuropeptidomic studies. Heat stabilization using focused microwave irradiation, conventional microwave irradiation, boiling, and treatment with the Denator Stabilizor T1 have all proven effective in arresting post-mortem protein degradation. Although research has reported the presence of protein fragments in crustacean hemolymph when protease inhibitors were not added to the sample, the degree to which postmortem protease activity affects neuropeptidomic tissue studies in crustacean species has not been investigated in depth. This work examines the need for Stabilizor T1 or boiling tissue stabilization methods for neuropeptide studies of Callinectes sapidus (blue crab) pericardial organ tissue. Neuropeptides in stabilized and non-stabilized tissue are extracted using acidified methanol or N,N-Dimethylformamide (DMF) and analyzed by MALDI-TOF and nanoLC-ESI-MS/MS platforms. Post-mortem fragments did not significantly affect MALDI analysis in the range m/z 650–1600, but observations in ESI MS/MS experiments suggest that putative post-mortem fragments can mask neuropeptide signal and add spectral complexity to crustacean neuropeptidomic studies. The impact of the added spectral complexity did not dramatically affect the number of detected neuropeptides between stabilized and non-stabilized tissues. However, it is prudent that neuropeptidomic studies of crustacean species include a preliminary experiment using the heat stabilization method to assess the extent of neuropeptide masking by larger, highly charged molecular species. PMID:23227893

  13. Evaluating Architectural Stability with Real Options Theory Rami Bahsoon and Wolfgang Emmerich

    E-print Network

    Emmerich, Wolfgang

    .ucl.ac.uk Abstract Architectural stability refers to the extent to which a soft- ware architecture is flexible enough. Economics-driven software engineering; rela- tionship between requirements and software architecture. 1. Introduction Architectural stability refers to the extent to which an architecture is flexible enough to endure

  14. Evaluation of an iterative model–based reconstruction algorithm for low-tube-voltage (80 kVp) computed tomography angiography

    PubMed Central

    Noël, Peter B.; Köhler, Thomas; Fingerle, Alexander A.; Brown, Kevin M.; Zabic, Stanislav; Münzel, Daniela; Haller, Bernhard; Baum, Thomas; Henninger, Martin; Meier, Reinhard; Rummeny, Ernst J.; Dobritz, Martin

    2014-01-01

    Abstract. The objective of this study was to investigate the improvement in diagnostic quality of an iterative model–based reconstruction (IMBR) algorithm for low-tube-voltage (80-kVp) and low-tube-current in abdominal computed tomography angiography (CTA). A total of 11 patients were imaged on a 256-slice multidetector computed tomography for visualization of the aorta. For all patients, three different reconstructions from the low-tube-voltage data are generated: filtered backprojection (FBP), IMBR, and a mixture of both IMBR+FBP. To determine the diagnostic value of IMBR-based reconstructions, the image quality was assessed. With IMBR-based reconstructions, image noise could be significantly reduced, which was confirmed by a highly improved contrast-to-noise ratio. In the image quality assessment, radiologists were able to reliably detect more third-order and higher aortic branches in the IMBR reconstructions compared to FBP reconstructions. The effective dose level was, on average, 3.0 mSv for 80-kVp acquisitions. Low-tube-voltage CTAs significantly improve vascular contrast as presented by others; however, this effect in combination with IMBR enabled yet another substantial improvement of diagnostic quality. For IMBR, a significant improvement of image quality and a decreased radiation dose at low-tube-voltage can be reported. PMID:26158054

  15. 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.

  16. Montezuma Creek Stability Evaluation at Site of Former Monticello Tailings Pile

    SciTech Connect

    Korte, N.

    2001-10-04

    This report documents the results of an evaluation of stream stability for Montezuma Creek downstream of the former uranium and vanadium millsite at Monticello, Utah. The work was performed by personnel from Oak Ridge National Laboratory's (ORNL's) Environmental Technology Section (ETS). ORNL/ETS was the Independent Verification Contractor (IVC) for the Monticello projects, and it established independent verification strategies that provided the U.S. Department of Energy (DOE) with a third-party assessment of whether remedial action had effectively reduced levels of contamination and whether supporting documentation that described the remediation was adequate. The DOE regulation 10 CFR 1022, which implements Executive Orders 11988 and 11990 for the protection of wetlands and floodplains, provided the regulatory rationale for the activity. This report documents both the impact of millsite remedial activities and postremediation conditions of Montezuma Creek. The scientific rationale for the stream survey was that conventional engineering practices do not adequately account for varying hydrologic regimes nor do they address the entire riparian zone as an interrelated unit. As a result, modifications to streams consistently cause damage to the environment by increasing erosion and sedimentation. Field activities included the establishment of permanent cross sections and periodic measurements and surveys of physical characteristics. The data demonstrated an increase in downstream stream bank erosion when activities at the millsite were greatest. Note, however, that agricultural practices have also contributed to erosion and bank instability. Nevertheless, an increase in fine sediment and bank recession were correlated to the construction. In addition, the project documented the failure of best management practices such as silt fences, to control sediment loss. Furthermore, conventional engineering designs were used to reroute Montezuma Creek, an action that will require increased maintenance when compared to a natural channel. Although these latter actions remain the most common practices, it is recommended that DOE apply geomorphic designs at future sites.

  17. 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.

  18. 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...

  19. 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...

  20. Evaluation of Laser Stabilization and Imaging Systems for LCLS-II - Oral Presentation

    SciTech Connect

    Barry, Matthew

    2015-08-19

    This presentation covers data collected on two commercial laser stabilization systems, Guidestar-II and MRC, and two optical imaging systems. Additionally, general information about LCLS-II and how to go about continuing-testing is covered.

  1. 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.

  2. 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.

  3. Electrical safety for high voltage arrays

    NASA Technical Reports Server (NTRS)

    Marshall, N. A.

    1983-01-01

    A number of key electrical safety requirements for the high voltage arrays of central station photovoltaic power systems are explored. The suitability of representative industrial DC power switchgear for control and fault protection was evaluated. Included were AC/DC circuit breakers, electromechanical contactors and relays, load interruptors, cold disconnect devices, sectionalizing switches, and high voltage DC fuses. As appropriate, steady state and transient characteristics were analyzed. Failure modes impacting upon operation and maintenance safety were also identified, as were the voltage withstand and current interruption levels.

  4. Analysis of NSTX TF Joint Voltage Measurements

    SciTech Connect

    R, Woolley

    2005-10-07

    This report presents findings of analyses of recorded current and voltage data associated with 72 electrical joints operating at high current and high mechanical stress. The analysis goal was to characterize the mechanical behavior of each joint and thus evaluate its mechanical supports. The joints are part of the toroidal field (TF) magnet system of the National Spherical Torus Experiment (NSTX) pulsed plasma device operating at the Princeton Plasma Physics Laboratory (PPPL). Since there is not sufficient space near the joints for much traditional mechanical instrumentation, small voltage probes were installed on each joint and their voltage monitoring waveforms have been recorded on sampling digitizers during each NSTX ''shot''.

  5. 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.

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

    NASA Technical Reports Server (NTRS)

    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.

  7. Laboratory evaluation of the pointing stability of the ASPS Vernier System

    NASA Technical Reports Server (NTRS)

    1980-01-01

    The annular suspension and pointing system (ASPS) is an end-mount experiment pointing system designed for use in the space shuttle. The results of the ASPS Vernier System (AVS) pointing stability tests conducted in a laboratory environment are documented. A simulated zero-G suspension was used to support the test payload in the laboratory. The AVS and the suspension were modelled and incorporated into a simulation of the laboratory test. Error sources were identified and pointing stability sensitivities were determined via simulation. Statistical predictions of laboratory test performance were derived and compared to actual laboratory test results. The predicted mean pointing stability during simulated shuttle disturbances was 1.22 arc seconds; the actual mean laboratory test pointing stability was 1.36 arc seconds. The successful prediction of laboratory test results provides increased confidence in the analytical understanding of the AVS magnetic bearing technology and allows confident prediction of in-flight performance. Computer simulations of ASPS, operating in the shuttle disturbance environment, predict in-flight pointing stability errors less than 0.01 arc seconds.

  8. Stability of smooth and rough mini-implants: clinical and biomechanical evaluation - an in vivostudy

    PubMed Central

    Vilani, Giselle Naback Lemes; Ruellas, Antônio Carlos de Oliveira; Elias, Carlos Nelson; Mattos, Cláudia Trindade

    2015-01-01

    Objective: To compare in vivo orthodontic mini-implants (MI) of smooth (machined) and rough (acid etched) surfaces, assessing primary and secondary stability. Methods: Thirty-six (36) MI were inserted in the mandibles of six (6) dogs. Each animal received six (6) MI. In the right hemiarch, three (3) MI without surface treatment (smooth) were inserted, whereas in the left hemiarch, another three (3) MI with acid etched surfaces (rough) were inserted. The two distal MI in each hemiarch received an immediate load of 1.0 N for 16 weeks, whereas the MI in the mesial extremity was not subject to loading. Stability was measured by insertion and removal torque, initial and final mobility and by inter mini-implant distance. Results: There was no statistical behavioral difference between smooth and rough MI. High insertion torque and reduced initial mobility were observed in all groups, as well as a reduction in removal torques in comparison with insertion torque. Rough MI presented higher removal torque and lower final mobility in comparison to smooth MI. MI did not remain static, with displacement of rough MI being smaller in comparison with smooth MI, but with no statistical difference. Conclusions: MI primary stability was greater than stability measured at removal. There was no difference in stability between smooth and rough MI when assessing mobility, displacement and insertion as well as removal torques. PMID:26560819

  9. 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.

  10. 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.

  11. 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

  12. Voltage balanced multilevel voltage source converter system

    DOEpatents

    Peng, Fang Zheng (Oak Ridge, TN); Lai, Jih-Sheng (Knoxville, TN)

    1997-01-01

    A voltage balanced multilevel converter for high power AC applications such as adjustable speed motor drives and back-to-back DC intertie of adjacent power systems. This converter provides a multilevel rectifier, a multilevel inverter, and a DC link between the rectifier and the inverter allowing voltage balancing between each of the voltage levels within the multilevel converter. The rectifier is equipped with at least one phase leg and a source input node for each of the phases. The rectifier is further equipped with a plurality of rectifier DC output nodes. The inverter is equipped with at least one phase leg and a load output node for each of the phases. The inverter is further equipped with a plurality of inverter DC input nodes. The DC link is equipped with a plurality of rectifier charging means and a plurality of inverter discharging means. The plurality of rectifier charging means are connected in series with one of the rectifier charging means disposed between and connected in an operable relationship with each adjacent pair of rectifier DC output nodes. The plurality of inverter discharging means are connected in series with one of the inverter discharging means disposed between and connected in an operable relationship with each adjacent pair of inverter DC input nodes. Each of said rectifier DC output nodes are individually electrically connected to the respective inverter DC input nodes. By this means, each of the rectifier DC output nodes and each of the inverter DC input nodes are voltage balanced by the respective charging and discharging of the rectifier charging means and the inverter discharging means.

  13. Voltage balanced multilevel voltage source converter system

    DOEpatents

    Peng, F.Z.; Lai, J.S.

    1997-07-01

    Disclosed is a voltage balanced multilevel converter for high power AC applications such as adjustable speed motor drives and back-to-back DC intertie of adjacent power systems. This converter provides a multilevel rectifier, a multilevel inverter, and a DC link between the rectifier and the inverter allowing voltage balancing between each of the voltage levels within the multilevel converter. The rectifier is equipped with at least one phase leg and a source input node for each of the phases. The rectifier is further equipped with a plurality of rectifier DC output nodes. The inverter is equipped with at least one phase leg and a load output node for each of the phases. The inverter is further equipped with a plurality of inverter DC input nodes. The DC link is equipped with a plurality of rectifier charging means and a plurality of inverter discharging means. The plurality of rectifier charging means are connected in series with one of the rectifier charging means disposed between and connected in an operable relationship with each adjacent pair of rectifier DC output nodes. The plurality of inverter discharging means are connected in series with one of the inverter discharging means disposed between and connected in an operable relationship with each adjacent pair of inverter DC input nodes. Each of said rectifier DC output nodes are individually electrically connected to the respective inverter DC input nodes. By this means, each of the rectifier DC output nodes and each of the inverter DC input nodes are voltage balanced by the respective charging and discharging of the rectifier charging means and the inverter discharging means. 15 figs.

  14. High voltage DC power supply

    DOEpatents

    Droege, Thomas F. (Batavia, IL)

    1989-01-01

    A high voltage DC power supply having a first series resistor at the output for limiting current in the event of a short-circuited output, a second series resistor for sensing the magnitude of output current, and a voltage divider circuit for providing a source of feedback voltage for use in voltage regulation is disclosed. The voltage divider circuit is coupled to the second series resistor so as to compensate the feedback voltage for a voltage drop across the first series resistor. The power supply also includes a pulse-width modulated control circuit, having dual clock signals, which is responsive to both the feedback voltage and a command voltage, and also includes voltage and current measuring circuits responsive to the feedback voltage and the voltage developed across the second series resistor respectively.

  15. High voltage DC power supply

    DOEpatents

    Droege, T.F.

    1989-12-19

    A high voltage DC power supply having a first series resistor at the output for limiting current in the event of a short-circuited output, a second series resistor for sensing the magnitude of output current, and a voltage divider circuit for providing a source of feedback voltage for use in voltage regulation is disclosed. The voltage divider circuit is coupled to the second series resistor so as to compensate the feedback voltage for a voltage drop across the first series resistor. The power supply also includes a pulse-width modulated control circuit, having dual clock signals, which is responsive to both the feedback voltage and a command voltage, and also includes voltage and current measuring circuits responsive to the feedback voltage and the voltage developed across the second series resistor respectively. 7 figs.

  16. 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

  17. Evaluation of the correlation between insertion torque and primary stability of dental implants using a block bone test

    PubMed Central

    Bayarchimeg, Dorjpalam; Namgoong, Hee; Kim, Byung Kook; Kim, Myung Duk; Kim, Sungtae; Kim, Tae-Il; Seol, Yang Jo; Lee, Yong Moo; Ku, Young; Rhyu, In-Chul; Lee, Eun Hee

    2013-01-01

    Purpose Implant stability at the time of surgery is crucial for the long-term success of dental implants. Primary stability is considered of paramount importance to achieve osseointegration. The purpose of the present study was to investigate the correlation between the insertion torque and primary stability of dental implants using artificial bone blocks with different bone densities and compositions to mimic different circumstances that are encountered in routine daily clinical settings. Methods In order to validate the objectives, various sized holes were made in bone blocks with different bone densities (#10, #20, #30, #40, and #50) using a surgical drill and insertion torque together with implant stability quotient (ISQ) values that were measured using the Osstell Mentor. The experimental groups under evaluation were subdivided into 5 subgroups according to the circumstances. Results In group 1, the mean insertion torque and ISQ values increased as the density of the bone blocks increased. For group 2, the mean insertion torque values decreased as the final drill size expanded, but this was not the case for the ISQ values. The mean insertion torque values in group 3 increased with the thickness of the cortical bone, and the same was true for the ISQ values. For group 4, the mean insertion torque values increased as the cancellous bone density increased, but the correlation with the ISQ values was weak. Finally, in group 5, the mean insertion torque decreased as the final drill size increased, but the correlation with the ISQ value was weak. Conclusions Within the limitations of the study, it was concluded that primary stability does not simply depend on the insertion torque, but also on the bone quality. PMID:23508040

  18. Influence of Input Parameters on Dynamic Orbital Stability of Walking: In-Silico and Experimental Evaluation

    PubMed Central

    Riva, Federico; Bisi, Maria Cristina; Stagni, Rita

    2013-01-01

    Many measures aiming to assess the stability of human motion have been proposed in the literature, but still there is no commonly accepted way to define or quantify locomotor stability. Among these measures, orbital stability analysis via Floquet multipliers is still under debate. Some of the controversies concerning the use of this technique could lie in the absence of a standard implementation. The aim of this study was to analyse the influence of i) experimental measurement noise, ii) variables selected for the construction of the state space, and iii) number of analysed cycles on the outputs of orbital stability applied to walking. The analysis was performed on a 2-dimensional 5-link walking model and on a sample of 10 subjects performing long over-ground walks. Noise resulting from stereophotogrammetric and accelerometric measurement systems was simulated in the in-silico analysis. Maximum Floquet multipliers resulted to be affected by both number of analysed strides and state space composition. The effect of experimental noise was found to be slightly more potentially critical when analysing stereophotogrammetric data then when dealing with acceleration data. Experimental and model results were comparable in terms of overall trend, but a difference was found in the influence of the number of analysed cycles. PMID:24260498

  19. Influence of input parameters on dynamic orbital stability of walking: in-silico and experimental evaluation.

    PubMed

    Riva, Federico; Bisi, Maria Cristina; Stagni, Rita

    2013-01-01

    Many measures aiming to assess the stability of human motion have been proposed in the literature, but still there is no commonly accepted way to define or quantify locomotor stability. Among these measures, orbital stability analysis via Floquet multipliers is still under debate. Some of the controversies concerning the use of this technique could lie in the absence of a standard implementation. The aim of this study was to analyse the influence of i) experimental measurement noise, ii) variables selected for the construction of the state space, and iii) number of analysed cycles on the outputs of orbital stability applied to walking. The analysis was performed on a 2-dimensional 5-link walking model and on a sample of 10 subjects performing long over-ground walks. Noise resulting from stereophotogrammetric and accelerometric measurement systems was simulated in the in-silico analysis. Maximum Floquet multipliers resulted to be affected by both number of analysed strides and state space composition. The effect of experimental noise was found to be slightly more potentially critical when analysing stereophotogrammetric data then when dealing with acceleration data. Experimental and model results were comparable in terms of overall trend, but a difference was found in the influence of the number of analysed cycles. PMID:24260498

  20. 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.

  1. STABILIZATION OF MERCURY IN WASTE MATERIAL FROM THE SULFUR BANK MERCURY MINE, INNOVATIVE TECHNOLOGY EVALUATION REPORT

    EPA Science Inventory

    Three innovative technologies for stabilization of mercury were demonstrated in a treatability study performed on two waste rock materials from the Sulfur Bank Mercury Mine, a Superfund site in northern California. The treatability study was jointly sponsored by two EPA programs:...

  2. 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...

  3. AN EVALUATION OF FACTORS AFFECTING THE SOLIDIFICATION/STABILIZATION OF HEAVY METAL SLUDGE

    EPA Science Inventory

    Solidification/stabilization (SIS) of hazardous waste involves mixing the waste with a binder material to enhance the physical properties of the waste and to immobilize contaminants that may be detrimental to the environment. Many hazardous wastes contain materials that are know...

  4. 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…

  5. Safety evaluation for the interim stabilization of Tank 241-C-103

    SciTech Connect

    Geschke, G.R.

    1995-03-01

    This document provides the basis for interim stabilization of tank 241-C-103. The document covers the removal of the organic liquid layer and the aqueous supernatant from tank 241-C-103. Hazards are identified, consequences are calculated and controls to mitigate or prevent potential accidents are developed.

  6. Spatial analyses to evaluate multi-crop yield stability for a field

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This paper proposes that yield stability patterns exist for multiple crops planted on the same land area over a period of years that growers can use to their advantage in planning crop management strategies using precision agriculture technologies. This initial study examines the relationship of s...

  7. 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.

  8. A Gating Charge Transfer Center in Voltage Sensors

    SciTech Connect

    Tao, X.; Lee, A; Limapichat, W; Dougherty, D; MacKinnon, R

    2010-01-01

    Voltage sensors regulate the conformations of voltage-dependent ion channels and enzymes. Their nearly switchlike response as a function of membrane voltage comes from the movement of positively charged amino acids, arginine or lysine, across the membrane field. We used mutations with natural and unnatural amino acids, electrophysiological recordings, and x-ray crystallography to identify a charge transfer center in voltage sensors that facilitates this movement. This center consists of a rigid cyclic 'cap' and two negatively charged amino acids to interact with a positive charge. Specific mutations induce a preference for lysine relative to arginine. By placing lysine at specific locations, the voltage sensor can be stabilized in different conformations, which enables a dissection of voltage sensor movements and their relation to ion channel opening.

  9. 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...

  10. High-voltage distributors

    NASA Technical Reports Server (NTRS)

    Mcchesney, J. F., Jr.

    1974-01-01

    Two distributors reduce high-voltage breakdowns and corona discharges. Both distributors are constructed to prevent air traps and facilitate servicing without soldering. Occurrence of coronas is also minimized due to smooth surfaces of device.

  11. Imaging voltage in neurons

    PubMed Central

    Peterka, Darcy S.; Takahashi, Hiroto; Yuste, Rafael

    2011-01-01

    In the last decades, imaging membrane potential has become a fruitful approach to study neural circuits, especially in invertebrate preparations with large, resilient neurons. At the same time, particularly in mammalian preparations, voltage imaging methods suffer from poor signal to noise and secondary side effects, and they fall short of providing single-cell resolution when imaging of the activity of neuronal populations. As an introduction to these techniques, we briefly review different voltage imaging methods (including organic fluorophores, SHG chromophores, genetic indicators, hybrid, nanoparticles and intrinsic approaches), and illustrate some of their applications to neuronal biophysics and mammalian circuit analysis. We discuss their mechanisms of voltage sensitivity, from reorientation, electrochromic or electro-optical phenomena, to interaction among chromophores or membrane scattering, and highlight their advantages and shortcomings, commenting on the outlook for development of novel voltage imaging methods. PMID:21220095

  12. CT Angiography of the Head-and-Neck Vessels Acquired with Low Tube Voltage, Low Iodine, and Iterative Image Reconstruction: Clinical Evaluation of Radiation Dose and Image Quality

    PubMed Central

    Zhang, Wei-lan; Li, Min; Zhang, Bo; Geng, Hai-yang; Liang, Yin-qiang; Xu, Ke; Li, Song-bai

    2013-01-01

    Objectives We aimed to assess the effectiveness and feasibility of head-and-neck Computed Tomography Angiography (CTA) with low tube voltage and low concentration contrast media combined with iterative reconstruction algorithm. Methods 92 patients were randomly divided into group A and B: patients in group A received a conventional scan with 120 kVp and contrast media of 320 mgI/ml. Patients in group B, 80 kVp and contrast media of 270 mgI/ml were used along with iterative reconstruction algorithm techniques. Image quality, radiation dose and the effectively consumed iodine amount between two groups were analyzed and compared. Results Image quality of CTA of head-and-neck vessels obtained from patients in group B was significantly improved quantitatively and qualitatively. In addition, CT attenuation values in group B were also significantly higher than that in group A (p<0.001). Furthermore, compared with the protocol whereby 120 kVp and 320 mgI/dl were administrated, the mean radiation dose and consumed iodine amount in protocol B were also reduced by 50% and 15.6%, respectively (p<0.001). Conclusions With the help of iterative reconstruction algorithm techniques, the head-and-neck CTA with diagnostic quality can be adequately acquired with low tube voltage and low concentration contrast media. This method could be potentially extended to include any part of the body to reduce the risks related to ionizing radiation. PMID:24339936

  13. Evaluation on the stability of Hg in ABS disk CRM during measurements by wavelength dispersive X-ray fluorescence spectrometry.

    PubMed

    Ohata, Masaki; Kidokoro, Toshihiro; Hioki, Akiharu

    2012-01-01

    The stability of Hg in an acrylonitrile-butadiene-styrene disk certified reference material (ABS disk CRM, NMIJ CRM 8116-a) during measurements by wavelength dispersion X-ray fluorescence (WD-XRF) analysis was evaluated in this study. The XRF intensities of Hg (L(?)) and Pb (L(?)) as well as the XRF intensity ratios of Hg (L(?))/Pb (L(?)) observed under different X-ray tube current conditions as well as their irradiation time were examined to evaluate the stability of Hg in the ABS disk CRM. The observed XRF intensities and the XRF intensity ratios for up to 32 h of measurements under 80 mA of X-ray tube current condition were constant, even though the surface of the ABS disk CRM was charred by the X-ray irradiation with high current for a long time. Moreover, the measurements on Hg and Pb in the charred disks by an energy dispersive XRF (ED-XRF) spectrometer showed constant XRF intensity ratios of Hg (L(?))/Pb (L(?)). From these results, Hg in the ABS disk CRM was evaluated to be sufficiently stable for XRF analysis. PMID:23149612

  14. Low-voltage gyrotrons

    SciTech Connect

    Glyavin, M. Yu.; Zavolskiy, N. A.; Sedov, A. S.; Nusinovich, G. S.

    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).

  15. 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.

  16. Evaluation of the geologic relations and seismotectonic stability of the Yucca Mountain Area Nevada Nuclear Waste Site Investigation (NNWSI)

    SciTech Connect

    1995-09-30

    This report provides a summary of progress for the project {open_quotes}Evaluation of the Geologic Relations and Seismotectonic Stability of the Yucca Mountain Area, Nevada Nuclear Waste Site Investigation (NNWSI).{close_quotes} A similar report was previously provided for the period of 1 October 1993 to 30 September 1994. The report initially covers the activities of the General Task and is followed by sections that describe the progress of the other ongoing Tasks which are listed below. Task 1: Quaternary Tectonics Task 3: Mineral Deposits, Volcanic Geology Task 4: Seismology Task 5: Tectonics Task 8: Basinal Studies.

  17. Fiber-optic voltage measuring system

    NASA Astrophysics Data System (ADS)

    Ye, Miaoyuan; Nie, De-Xin; Li, Yan; Peng, Yu; Lin, Qi-Qing; Wang, Jing-Gang

    1993-09-01

    A new fibre optic voltage measuring system has been developed based on the electrooptic effect of bismuth germanium oxide (Bi4Ge3O12)crystal. It uses the LED as the light source. The light beam emitted from the light source is transmitted to the sensor through the optic fibre and the intensity of the output beam is changed by the applied voltage. This optic signal is transmitted to the PIN detector and converted to an electric signal which is processed by the electronic circuit and 8098 single chip microcomputer the output voltage signal obtained is directly proportional to the applied voltage. This paper describes the principle the configuration and the performance parameters of the system. Test results are evaluated and discussed.

  18. Correlation and evaluation of inplane stability characteristics for an advanced bearingless main rotor

    NASA Technical Reports Server (NTRS)

    Weller, W. H.

    1983-01-01

    A program of experimental and analytical research was performed to demonstrate the degree of correlation achieved between measured and computed rotor inplane stability characteristics. The experimental data were obtained from hover and wind tunnel tests of a scaled bearingless main rotor model. Both isolated rotor and free-hub conditions were tested. Test parameters included blade built-in cone and sweep angles; rotor inplane structural stiffness and damping; pitch link stiffness and location; and fuselage damping, inertia, and natural frequency. Analytical results for many test conditions were obtained. In addition, the analytical and experimental results were examined to ascertain the effects of the test parameters on rotor ground and air resonance stability. The results from this program are presented herein in tabular and graphical form.

  19. Optical S-ALOHA/CDMA Systems for Multirate Applications: Architecture, Performance Evaluation, and System Stability

    NASA Astrophysics Data System (ADS)

    Raad, Robert; Inaty, Elie; Fortier, Paul; Shalaby, Hossam M. H.

    2006-05-01

    In this paper, a new multirate optical network based on a hybrid slotted-ALOHA (S-ALOHA)/overlapped code division multiple access (O-CDMA) system is proposed as an effective way of integrating multiclass traffic. The key issue in this proposal is to exploit the potential of the optical O-CDMA using fiber Bragg gratings when jointly used with the S-ALOHA protocol in a link layer. The newly proposed system is modeled using a general Markov chain from which both the system throughput and the average packet delay are derived. The system stability passing through a general finite user model is also envisaged. The system is then compared to the classical S-ALOHA/variable processing gain (VPG) CDMA system. Numerical results show that the proposed system outperforms the latter one, especially at high transmission rates. In addition, stability measures demonstrate that the overlapped system tends to be more stable than the VPG system.

  20. In-Well Sediment Incubators to Evaluate Microbial Community Stability and Dynamics following Bioimmobilization of Uranium

    SciTech Connect

    Baldwin, Brett R.; Peacock, Aaron D.; Gan, M.; Resch, Charles T.; Arntzen, Evan V.; Smithgall, A. N.; Pfiffner, S.; Freifeld, Barry M.; White, D. C.; Long, Philip E.

    2009-09-23

    An in-situ incubation device (ISI) was developed in order to investigate the stability and dynamics of sediment associated microbial communities to prevailing subsurface oxidizing or reducing conditions. Here we describe the use of these devices at the Old Rifle Uranium Mill Tailings Remedial Action (UMTRA) site. During the 7 month deployment oxidized Rifle aquifer background sediments (RABS) were deployed in previously biostimulated wells under iron reducing conditions, cell densities of known iron reducing bacteria including Geobacteraceae increased significantly showing the microbial community response to local subsurface conditions. PLFA profiles of RABS following in situ deployment were strikingly similar to those of adjacent sediment cores suggesting ISI results could be extrapolated to the native material of the test plots. Results for ISI deployed reduced sediments showed only slight changes in community composition and pointed toward the ability of the ISIs to monitor microbial community stability and response to subsurface conditions.

  1. Preparation of iron bound succinylated milk protein concentrate and evaluation of its stability.

    PubMed

    Shilpashree, B G; Arora, Sumit; Sharma, Vivek; Bajaj, Rajesh Kumar; Tomar, S K

    2016-04-01

    Major problems associated with the fortification of soluble iron salts include chemical reactivity and incompatibility with other components. Milk protein concentrate (MPC) are able to bind significant amount of iron due to the presence of both casein and whey protein. MPC in its native state possess very poor solubility, therefore, succinylated derivatives of MPC (succ. MPC) were also used for the preparation of protein-iron complex. Preparation of the complex involved centrifugation (to remove insoluble iron), ultrafiltration (to remove unbound iron) and lyophilisation (to attain in dry form). Iron binding ability of MPC enhanced significantly (P<0.05) upon succinylation. Stability of bound iron from both varieties of complexes was monitored under different conditions encountered during processing. Higher stability (P<0.05) of bound iron was observed in succ. MPC-iron complex than native protein complex. This method could be adopted for the production of stable iron enriched protein, an organic iron source. PMID:26593557

  2. Device for monitoring cell voltage

    DOEpatents

    Doepke, Matthias (Garbsen, DE); Eisermann, Henning (Edermissen, DE)

    2012-08-21

    A device for monitoring a rechargeable battery having a number of electrically connected cells includes at least one current interruption switch for interrupting current flowing through at least one associated cell and a plurality of monitoring units for detecting cell voltage. Each monitoring unit is associated with a single cell and includes a reference voltage unit for producing a defined reference threshold voltage and a voltage comparison unit for comparing the reference threshold voltage with a partial cell voltage of the associated cell. The reference voltage unit is electrically supplied from the cell voltage of the associated cell. The voltage comparison unit is coupled to the at least one current interruption switch for interrupting the current of at least the current flowing through the associated cell, with a defined minimum difference between the reference threshold voltage and the partial cell voltage.

  3. 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

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

    NASA Astrophysics Data System (ADS)

    Lee, Tony R.; Wilkin, Richard T.

    2010-07-01

    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 (? fG°) 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.

  5. Utilization of phosphogypsum in tannery sludge stabilization and evaluation of the radiological impact.

    PubMed

    Pantazopoulou, E; Zebiliadou, O; Noli, F; Mitrakas, M; Samaras, P; Zouboulis, A

    2015-03-01

    The current global trend towards increasingly stringent environmental standards and efforts for efficient utilization and re-use of available by-products and/or wastes, favors the use of low-cost sorbent materials for the treatment of heavy metal-contaminated solid wastes. In this study, the stabilization of tannery sludge, produced from the physicochemical and biological treatment of tannery wastewaters, was examined by the addition of phosphogypsum (PG) at a ratio of 1:1. Characterization of the tannery sludge leachates showed high amounts of chromium which exceeded the acceptable level for disposal in non-hazardous waste landfills, while the dissolved organic carbon (DOC) concentrations exceeded the limits for disposal in landfills for hazardous wastes, according to the EU Decision 2003/33/EC. Leachates of the waste stabilized with PG presented chromium and DOC concentrations below the regulation limits for disposal in landfills for non-hazardous wastes. Moreover, mixing PG with tannery sludge resulted in a stabilized waste with reduced radioactivity. PMID:25432294

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

    SciTech Connect

    Wilkin, Richard T.; Lee, T.R.

    2010-10-22

    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}{sub f}G{sup o}) 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.

  7. 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

  8. Preparation and in vivo evaluation of PCADK/PLGA microspheres for improving stability and efficacy of rhGH.

    PubMed

    Wang, Chenhui; Yu, Changhui; Liu, Jiaxin; Teng, Lesheng; Sun, Fengying; Li, Youxin

    2015-11-30

    The goal of this research is to prepare poly(cyclohexane-1,4 diyl acetone dimethylene ketal) (PCADK)/poly(d,l-lactide-co-glycolide) (PLGA) blend microspheres loaded with recombinant human growth hormone (rhGH). The effect of PCADK degradation products on the structural integrity, secondary and tertiary structure and pharmacodynamics of rhGH was evaluated by native-polyacrylamide gel electrophoresis (Native-PAGE), size-exclusion high performance liquid chromatography (SEC-HPLC), circular dichroism (CD), fluorescence spectroscopy and in hypophysectomized rat models. Compared with PLGA degradation products, rhGH was found to be more stable in the presence of PCADK degradation products. PCADK/PLGA blend microspheres were then prepared and the morphology, encapsulation efficiency, release behavior and rhGH stability were investigated. PCADK/PLGA microspheres had regular shapes and smooth surfaces when the proportion of PCADK was less than 50%. The late-releasable amount of rhGH in PCADK/PLGA microspheres was greater than that in PLGA microspheres. In addition, the PCADK/PLGA microspheres showed larger AUC and improved therapeutic effects on rats than PLGA microspheres. Furthermore, the pH inside the microspheres was detected by CLSM to explain the improved rhGH stability in the PCADK/PLGA microspheres. In conclusion, PCADK/PLGA blend microspheres showed potential to improve rhGH stability and the efficacy of sustained-release of rhGH compared with PLGA microspheres. PMID:26456269

  9. 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

  10. Precision evaluation of chiral capillary electrophoretic methods in the context of inter-instrumental transfer: constant current versus constant voltage application.

    PubMed

    De Cock, Bart; Dejaegher, Bieke; Stiens, Johan; Mangelings, Debby; Vander Heyden, Yvan

    2014-08-01

    Capillary electrophoresis (CE) is an electrophoretic separation technique that was rapidly increasing in popularity some years ago and that led to high expectations. Because of their different separation mechanisms, CE and HPLC are alternative and complementary separation techniques. Chiral molecules can be directly separated with CE by simply adding a chiral selector to the running buffer solution, leading to flexible and cheap methods. Major drawbacks of capillary electrophoretic separation methods are, however, the lower precision compared to HLPC methods and a more problematic analytical method transfer. Both above stated disadvantages limit the generalized use of CE methods in the pharmaceutical industry. Multiple solutions have been suggested to improve the precision of CE methods. In this work the application of a constant current during the electrophoretic separation instead of the more commonly used application of a constant voltage was studied on two CE instruments with different cooling mechanisms. This was done in the context of optimizing method transfer conditions. A constant current may reduce the generation of heat in the capillary and the consequentially radial and axial temperature fluctuations that both negatively influence the precision of the peak areas, migration times and resolutions of a CE method. The repeatability and time-different intermediate precision of both electrophoretic separation modes were compared on two different CE instruments after a successful analytical method transfer. The chiral separations of three beta-blockers, propranolol, sotalol and betaxolol, were used as test cases. A constant current led to a general improvement of the repeatability and time-different intermediate precision of the relative Area Under the Curve of all three beta-blockers, while that of the migration times remained rather constant. It also led to more similar electropherograms than the application of a constant voltage. PMID:24680945

  11. 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.

  12. 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.

  13. Evaluation of a Cognitive Rehabilitation Protocol in HIV Patients with Associated Neurocognitive Disorders: Efficacy and Stability Over Time

    PubMed Central

    Livelli, Alessandro; Orofino, Gian Carlo; Calcagno, Andrea; Farenga, Mariana; Penoncelli, Donatella; Guastavigna, Marta; Carosella, Sinibaldo; Caramello, Pietro; Pia, Lorenzo

    2015-01-01

    The primary aim of the present study was to evaluate the efficacy and stability over time of a cognitive rehabilitation protocol (restorative and compensatory approach) in HIV/AIDS patients with HIV-associated Neurocognitive Disorder (HAND). At baseline, 32 HIV/AIDS patients (16 with and 16 without HAND) were assessed with a neuropsychological battery (i.e., pre-assessment) consisting of 22 tests covering eight cognitive domains. Then, the experimental group was administered over 4 months a cognitive rehabilitation protocol aimed at improving four cognitive domains by means of eight paper and pencil/computer-based exercises. The control group received guideline-adherent clinical care (i.e., standard of care). At the end of the cognitive treatment, both groups were re-administered the neuropsychological battery (i.e., post-assessment). Additionally, 6 months after post-assessment, the experimental group was given the same neuropsychological battery (i.e., follow up-assessment). In order to test the efficacy of the cognitive rehabilitation protocol, we compared between groups the results of the neuropsychological battery at the pre- and post-assessments. In order to evaluate the stability over time, the effects of the cognitive rehabilitation protocol was examined comparing within the experimental group the results of the neuropsychological battery at post- and follow up-assessments. Our results show that the two groups did not differ at the pre-assessment, but differed at post-assessment. Specifically, the experimental group showed a significant improvement in five domains (Learning and memory, Abstraction/executive functioning, Verbal fluency, Attention/working memory, and Functional), whereas the control group significantly worsened in the same domains. The improvement of the experimental group did not change in the follow up-assessment in two domains (Abstraction/executive functioning, Attention/working memory, and Functional). Overall, these findings support the efficacy and, to some extent, the stability over time of our cognitive rehabilitation protocol. PMID:26635558

  14. Evaluation of Reinforcement and Analysis of Stability of a High-Arch Dam Based on Geomechanical Model Testing

    NASA Astrophysics Data System (ADS)

    Zhang, L.; Liu, Y. R.; Yang, Q.

    2015-03-01

    Reinforcement measures are often used in high-arch dams with complicated geological foundations. The geomechanical model test is an effective method to study the global stability of arch dams and to evaluate the reinforcement effects of foundation treatments. The block masonry technique was developed to simulate the jointed rock mass, tectonic discontinuities, and reinforcement measures. A tailor-made low-strength binder and small blocks were developed to simulate the strength and deformation of the jointed rock mass and discontinuities, respectively. We applied this technique to geomechanical model tests of the Dagangshan arch dam with and without foundation reinforcements. A rupture test was conducted, and the stress and displacement distribution of the dam and abutments were recorded; the failure mechanisms and processes were explored. The reinforcement effects of the foundation treatment were evaluated by comparing the test results of the models with and without foundation reinforcements. Our analysis indicates that foundation reinforcements can improve the stress distribution, decrease deformation, prevent slides, reduce fault movement, and improve the global stability of high-arch dams.

  15. Evaluation of microwave oven heating for prediction of drug-excipient compatibilities and accelerated stability studies.

    PubMed

    Schou-Pedersen, Anne Marie V; Østergaard, Jesper; Cornett, Claus; Hansen, Steen Honoré

    2015-05-15

    Microwave ovens have been used extensively in organic synthesis in order to accelerate reaction rates. Here, a set up comprising a microwave oven combined with silicon carbide (SiC) plates for the controlled microwave heating of model formulations has been applied in order to investigate, if a microwave oven is applicable for accelerated drug stability testing. Chemical interactions were investigated in three selected model formulations of drug and excipients regarding the formation of ester and amide reaction products. In the accelerated stability studies, a design of experiments (DoE) approach was applied in order to be able to rank excipients regarding reactivity: Study A: cetirizine with PEG 400, sorbitol, glycerol and propylene glycol. Study B: 6-aminocaproic acid with citrate, acetate, tartrate and gluconate. Study C: atenolol with citric, tartaric, malic, glutaric, and sorbic acid. The model formulations were representative for oral solutions (co-solvents), parenteral solutions (buffer species) and solid dosage forms (organic acids applicable for solubility enhancement). The DoE studies showed overall that the same impurities were generated by microwave oven heating leading to temperatures between 150°C and 180°C as compared to accelerated stability studies performed at 40°C and 80°C using a conventional oven. Ranking of the reactivity of the excipients could be made in the DoE studies performed at 150-180°C, which was representative for the ranking obtained after storage at 40°C and 80°C. It was possible to reduce the time needed for drug-excipient compatibility testing of the three model formulations from weeks to less than an hour in the three case studies. The microwave oven is therefore considered to be an interesting alternative to conventional thermal techniques for the investigation of drug-excipient interactions during preformulation. PMID:25746946

  16. 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.

  17. Experimental Evaluation of Journal Bearing Stability and New Gas Wave Bearing Materials

    NASA Technical Reports Server (NTRS)

    Keith, Theo G., Jr.; Dimofte, Florin

    1998-01-01

    A gas journal bearing, with a wavy surfaces was tested in a range of speeds up to 18,000 RPM to determine its stability in an unloaded condition as a function of the wave amplitude. The bearing, was 50 mm in diameter, 58 mm long and had 0.01 65 mm radial clearance. Three waves were created on the inner surface by deforming the bearing sleeve. The ratio of the wave amplitude to the radial clearance (the wave amplitude ratio) was varied from zero to 0.3.

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

    SciTech Connect

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

    2013-07-15

    Highlights: • Solvita® stability and maturity tests used on composting toilet end-product. • Solvita® ammonia better suited in evaluation of feedstock suitability for vermicomposting. • No clear value of Solvita® stability test due to prevalent inhibition of decomposition by ammonia. - Abstract: 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® CO{sub 2} test as having high stability values.

  19. Surface voltage gradient role in high voltage solar array-plasma interaction: Center Director's discretionary fund

    NASA Technical Reports Server (NTRS)

    Carruth, M. R., Jr.

    1985-01-01

    A large amount of experimental and analytical effort has been directed toward understanding the plasma sheath growth and discharge phenomena which lead to high voltage solar array-space plasma interactions. An important question which has not been addressed is how the surface voltage gradient on such an array may affect these interactions. The results of this study indicate that under certain conditions, the voltage gradient should be taken into account when evaluating the effect on a solar array operating in a plasma environment.

  20. Voltage controlled current source

    DOEpatents

    Casne, Gregory M. (Pittsburgh, PA)

    1992-01-01

    A seven decade, voltage controlled current source is described for use in testing intermediate range nuclear instruments that covers the entire test current range of from 10 picoamperes to 100 microamperes. High accuracy is obtained throughout the entire seven decades of output current with circuitry that includes a coordinated switching scheme responsive to the input signal from a hybrid computer to control the input voltage to an antilog amplifier, and to selectively connect a resistance to the antilog amplifier output to provide a continuous output current source as a function of a preset range of input voltage. An operator controlled switch provides current adjustment for operation in either a real-time simulation test mode or a time response test mode.

  1. High voltage coaxial switch

    DOEpatents

    Rink, J.P.

    1983-07-19

    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. 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. 3 figs.

  2. High voltage coaxial switch

    DOEpatents

    Rink, John P. (Los Alamos, NM)

    1983-07-19

    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. 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.

  3. 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.

  4. 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.

  5. Power supply design for the filament of the high-voltage electron accelerator

    NASA Astrophysics Data System (ADS)

    Zhang, Lige; Yang, Lei; Yang, Jun; Huang, Jiang; Liu, Kaifeng; Zuo, Chen

    2015-12-01

    The filament is a key component for the electron emission in the high-voltage electron accelerator. In order to guarantee the stability of the beam intensity and ensure the proper functioning for the power supply in the airtight steel barrel, an efficient filament power supply under accurate control is required. The paper, based on the dual-switch forward converter and synchronous rectification technology, puts forward a prototype of power supply design for the filament of the high-voltage accelerator. The simulation is conducted with MATLAB-Simulink on the main topology and the control method. Loss analysis and thermal analysis are evaluated using the FEA method. Tests show that in this prototype, the accuracy of current control is higher than 97.5%, and the efficiency of the power supply reaches 87.8% when the output current is 40 A.

  6. Geomagnetism and induced voltage

    NASA Astrophysics Data System (ADS)

    Abdul-Razzaq, W.; Biller, R. D.

    2010-07-01

    Introductory physics laboratories have seen an influx of conceptual integrated science over time in their classrooms with elements of other sciences such as chemistry, biology, Earth science, and astronomy. We describe a laboratory to introduce this development, as it attracts attention to the voltage induced in the human brain as it is initiated by the change in the magnetic flux due to the Earth's magnetic field and movement. This simple and enjoyable experiment will demonstrate how basic concepts in physics and geology can help us think about possible health effects due to the induced voltage.

  7. Optical sensing in high voltage transmission lines using power over fiber and free space optics

    NASA Astrophysics Data System (ADS)

    Rosolem, João Batista; Bassan, Fabio Renato; Penze, Rivael Strobel; Leonardi, Ariovaldo Antonio; Fracarolli, João Paulo Vicentini; Floridia, Claudio

    2015-12-01

    In this work we propose the use of power over fiber (PoF) and free space optics (FSO) techniques to powering and receive signals from an electrical current sensor placed at high voltage potential using a pair of optical collimators. The technique evaluation was performed in a laboratorial prototype using 62.5/125 ?m multimode fiber to study the sensitivity of the optical alignment and the influence of the collimation process in the sensing system wavelengths: data communication (1310 nm) and powering (830 nm). The collimators were installed in a rigid electric insulator in order to maintain the stability of transmission.

  8. 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.

  9. 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.

  10. Evaluation of MegaVoltage Cone Beam CT image quality with an unmodified Elekta Precise Linac and EPID: a feasibility study.

    PubMed

    Markwell, Tim; Perera, Lakshal; Trapp, Jamie; Fielding, Andrew

    2014-06-01

    In order to increase the accuracy of patient positioning for complex radiotherapy treatments various 3D imaging techniques have been developed. MegaVoltage Cone Beam CT (MVCBCT) can utilise existing hardware to implement a 3D imaging modality to aid patient positioning. MVCBCT has been investigated using an unmodified Elekta Precise Linac and iView amorphous silicon electronic portal imaging device (EPID). Two methods of delivery and acquisition have been investigated for imaging an anthropomorphic head phantom and quality assurance phantom. Phantom projections were successfully acquired and CT datasets reconstructed using both acquisition methods. Bone, tissue and air were clearly resolvable in both phantoms even with low dose (22 MU) scans. The feasibility of MVCBCT was investigated using a standard linac, amorphous silicon EPID and a combination of a free open source reconstruction toolkit as well as custom in-house software written in Matlab. The resultant image quality has been assessed and presented. Although bone, tissue and air were resolvable in all scans, artifacts are present and scan doses are increased when compared with standard portal imaging. The feasibility of MVCBCT with unmodified Elekta Precise Linac and EPID has been considered as well as the identification of possible areas for future development in artifact correction techniques to further improve image quality. PMID:24609762

  11. Evaluation of Stability and Biological Activity of Solid Nanodispersion of Lambda-Cyhalothrin

    PubMed Central

    Cui, Bo; Feng, Lei; Pan, Zhenzhong; Yu, Manli; Zeng, Zhanghua; Sun, Changjiao; Zhao, Xiang; Wang, Yan; Cui, Haixin

    2015-01-01

    Pesticides are essential agrochemicals used to protect plants from diseases, pests and weeds. However, the formulation defects of conventional pesticides cause food toxicity and ecological environmental problems. In this study, a novel, efficient and environmentally friendly formulation of lambda-cyhalothrin, a solid nanodispersion, was successfully developed based on melt-emulsification and high-speed shearing methods. The solid nanodispersion presented excellent advantages over conventional pesticide formulations in such formulation functions as dispersibility, stability and bioavailability. The formulation is free of organic solvents, and the use of surfactant is reduced. Therefore, the application of the solid nanodispersion in crop production will improve efficacy and reduce the occurrence of both pesticide residues in food and environmental pollution from pesticides. PMID:26281043

  12. Development and validation of an evaporation duct model. Part II: Evaluation and improvement of stability functions

    NASA Astrophysics Data System (ADS)

    Ding, Juli; Fei, Jianfang; Huang, Xiaogang; Cheng, Xiaoping; Hu, Xiaohua; Ji, Liang

    2015-06-01

    This study aims to validate and improve the universal evaporation duct (UED) model through a further analysis of the stability function ( ?). A large number of hydrometeorological observations obtained from a tower platform near Xisha Island of the South China Sea are employed, together with the latest variations in ? function. Applicability of different ? functions for specific sea areas and stratification conditions is investigated based on three objective criteria. The results show that, under unstable conditions, ? function of Fairall et al. (1996) (i.e., Fairall96, similar for abbreviations of other function names) in general offers the best performance. However, strictly speaking, this holds true only for the stability (represented by bulk Richardson number R iB) range -2.6 ? R iB < -0.1; when conditions become weakly unstable (-0.1 ? R iB < -0.01), Fairall96 offers the second best performance after Hu and Zhang (1992) (HYQ92). Conversely, for near-neutral but slightly unstable conditions (-0.01 ? R iB < 0.0), the effects of Edson04, Fairall03, Grachev00, and Fairall96 are similar, with Edson04 being the best function but offering only a weak advantage. Under stable conditions, HYQ92 is the optimal and offers a pronounced advantage, followed by the newly introduced SHEBA07 (by Grachev et al., 2007) function. Accordingly, the most favorable functions, i.e., Fairall96 and HYQ92, are incorporated into the UED model to obtain an improved version of the model. With the new functions, the mean root-mean-square (rms) errors of the modified refractivity ( M), 0-5-m M slope, 5-40-m M slope, and the rms errors of evaporation duct height (EDH) are reduced by 21.65%, 9.12%, 38.79%, and 59.06%, respectively, compared to the classical Naval Postgraduate School model.

  13. Phase stability and biological property evaluation of plasma sprayed hydroxyapatite coatings for orthopedic and dental applications.

    PubMed

    Vahabzadeh, Sahar; Roy, Mangal; Bandyopadhyay, Amit; Bose, Susmita

    2015-04-01

    In this work we have investigated the effects of strontium (Sr) dopant on in vitro protein release kinetics and in vivo osteogenic properties of plasma sprayed hydroxyapatite (HA) coatings, along with their dissolution behavior. Plasma sprayed HA coatings are widely used in load-bearing implants. Apart from osseointegration, the new generation of HA coating is expected to deliver biomolecules and/or drugs that can induce osteoinduction. This paper reports the preparation of crystalline and amorphous HA coatings on commercially pure titanium (Cp-Ti) using inductively coupled radio frequency (RF) plasma spray, and their stability at different solution pH. Coatings prepared at 110 mm working distance from the nozzle showed an average Ca ion release of 18 and 90 ppm in neutral and acidic environments, respectively. Decreasing the working distance to 90 mm resulted in the formation of a coating with less crystalline HA and phases with higher solubility products, and consequently higher dissolution over 32 days. A 92% release of a model protein bovine serum albumin (BSA) in phosphate buffer with pH of 7.4 was measured for Sr-doped HA (Sr-HA) coating, while only a 72% release could be measured for pure HA coating. Distortion of BSA during adsorption on coatings revealed a strong interaction between the protein and the coating, with an increase in ?-helix content. Osteoid formation was found on Sr-HA implants as early as 7 weeks post implantation compared to HA coated and uncoated Ti implants. After 12 weeks post implantation, osteoid new bone was formed on HA implants; whereas, bone mineralization started on Sr-HA samples. While no osteoid was formed on bare Ti surfaces, bone was completely mineralized on HA and Sr-HA coatings after 16 weeks post implantation. Our results show that both phase stability and chemistry can have a significant influence toward in vitro and in vivo response of HA coatings on Ti implants. PMID:25638672

  14. 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.

  15. 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 of Aequorea victoria green fluorescent protein (GFP) emitting blue, cyan and yellow and the discovery of GFP have been developed for fluorescence resonance energy transfer (FRET) applications2. Unimolecular

  16. Geomagnetism and Induced Voltage

    ERIC Educational Resources Information Center

    Abdul-Razzaq, W.; Biller, R. D.

    2010-01-01

    Introductory physics laboratories have seen an influx of "conceptual integrated science" over time in their classrooms with elements of other sciences such as chemistry, biology, Earth science, and astronomy. We describe a laboratory to introduce this development, as it attracts attention to the voltage induced in the human brain as it is…

  17. 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.

  18. 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

  19. Modulation of BK channel voltage gating by different auxiliary ? subunits

    PubMed Central

    Contreras, Gustavo F.; Neely, Alan; Alvarez, Osvaldo; Gonzalez, Carlos; Latorre, Ramon

    2012-01-01

    Calcium- and voltage-activated potassium channels (BK) are regulated by a multiplicity of signals. The prevailing view is that different BK gating mechanisms converge to determine channel opening and that these gating mechanisms are allosterically coupled. In most instances the pore forming ? subunit of BK is associated with one of four alternative ? subunits that appear to target specific gating mechanisms to regulate the channel activity. In particular, ?1 stabilizes the active configuration of the BK voltage sensor having a large effect on BK Ca2+ sensitivity. To determine the extent to which ? subunits regulate the BK voltage sensor, we measured gating currents induced by the pore-forming BK ? subunit alone and with the different ? subunits expressed in Xenopus oocytes (?1, ?2IR, ?3b, and ?4). We found that ?1, ?2, and ?4 stabilize the BK voltage sensor in the active conformation. ?3 has no effect on voltage sensor equilibrium. In addition, ?4 decreases the apparent number of charges per voltage sensor. The decrease in the charge associated with the voltage sensor in ? ?4 channels explains most of their biophysical properties. For channels composed of the ? subunit alone, gating charge increases slowly with pulse duration as expected if a significant fraction of this charge develops with a time course comparable to that of K+ current activation. In the presence of ?1, ?2, and ?4 this slow component develops in advance of and much more rapidly than ion current activation, suggesting that BK channel opening proceeds in two steps. PMID:23112204

  20. 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.

  1. 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

  2. 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

  3. Evaluation of the geological relationships to gas hydrate formation and stability

    SciTech Connect

    Krason, J.; Finley, P.

    1988-01-01

    The summaries of regional basin analyses document that potentially economic accumulations of gas hydrates can be formed in both active and passive margin settings. The principal requirement for gas hydrate formation in either setting is abundant methane. Passive margin sediments with high sedimentation rates and sufficient sedimentary organic carbon can generate large quantities of biogenic methane for hydrate formation. Similarly, active margin locations near a terrigenous sediment source can also have high methane generation potential due to rapid burial of adequate amounts of sedimentary organic matter. Many active margins with evidence of gas hydrate presence correspond to areas subject to upwelling. Upwelling currents can enhance methane generation by increasing primary productivity and thus sedimentary organic carbon. Structural deformation of the marginal sediments at both active and passive sites can enhance gas hydrate formation by providing pathways for migration of both biogenic and thermogenic gas to the shallow gas hydrate stability zone. Additionally, conventional hydrocarbon traps may initially concentrate sufficient amounts of hydrocarbons for subsequent gas hydrate formation.

  4. 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.

  5. Deep sequencing approach for genetic stability evaluation of influenza A viruses.

    PubMed

    Bidzhieva, Bella; Zagorodnyaya, Tatiana; Karagiannis, Konstantinos; Simonyan, Vahan; Laassri, Majid; Chumakov, Konstantin

    2014-04-01

    Assessment of genetic stability of viruses could be used to monitor manufacturing process of both live and inactivated viral vaccines. Until recently such studies were limited by the difficulty of detecting and quantifying mutations in heterogeneous viral populations. High-throughput sequencing technologies (deep sequencing) can generate massive amounts of genetic information and could be used to reveal and quantify mutations. Comparison of different approaches for deep sequencing of the complete influenza A genome was performed to determine the best way to detect and quantify mutants in attenuated influenza reassortant strain A/Brisbane/59/2007 (H1N1) and its passages in different cell substrates. Full-length amplicons of influenza A virus segments as well as multiple overlapping amplicons covering the entire viral genome were subjected to several ways of DNA library preparation followed by deep sequencing using Solexa (Illumina) and pyrosequencing (454 Life Science) technologies. Sequencing coverage (the number of times each nucleotide was determined) of mutational profiles generated after 454-pyrosequencing of individually synthesized overlapping amplicons were relatively low and insufficiently uniform. Amplification of the entire genome of influenza virus followed by its enzymatic fragmentation, library construction, and Illumina sequencing resulted in high and uniform sequencing coverage enabling sensitive quantitation of mutations. A new bioinformatic procedure was developed to improve the post-alignment quality control for deep-sequencing data analysis. PMID:24406624

  6. Stability of Norwalk Virus Capsid Protein Interfaces Evaluated by in Silico Nanoindentation

    PubMed Central

    Boyd, Kevin J.; Bansal, Prakhar; Feng, Jun; May, Eric R.

    2015-01-01

    Norwalk virus causes severe gastroenteritis for which there is currently no specific anti-viral therapy. A stage of the infection process is uncoating of the protein capsid to expose the viral genome and allow for viral replication. A mechanical characterization of the Norwalk virus may provide important information relating to the mechanism of uncoating. The mechanical strength of the Norwalk virus has previously been investigated using atomic force microscopy (AFM) nanoindentation experiments. Those experiments cannot resolve specific molecular interactions, and therefore, we have employed a molecular modeling approach to gain insights into the potential uncoating mechanism of the Norwalk capsid. In this study, we perform simulated nanoindentation using a coarse-grained structure-based model, which provides an estimate of the spring constant in good agreement with the experimentally determined value. We further analyze the fracture mechanisms and determine weak interfaces in the capsid structure, which are potential sites to inhibit uncoating by stabilization of these weak interfaces. We conclude by identifying potential target sites at the junction of a weak protein–protein interface. PMID:26284238

  7. 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.

  8. Alginate stabilized gold nanoparticle as multidrug carrier: Evaluation of cellular interactions and hemolytic potential.

    PubMed

    Dey, Soma; Sherly, M Caroline Diana; Rekha, M R; Sreenivasan, K

    2016-01-20

    This work delineates the synthesis of curcumin (Ccm) and methotrexate (MTX) conjugated biopolymer stabilized AuNPs (MP@Alg-Ccm AuNPs). The dual drug conjugated nano-vector was characterized by FTIR, (1)H NMR and UV-vis spectroscopic techniques. Hydrodynamic diameter and surface charge of the AuNPs were determined by DLS analysis and the spherical particles were visualized by TEM. MP@Alg-Ccm AuNPs exhibited improved cytotoxic potential against C6 glioma and MCF-7 cancer cell lines and was found to be highly hemocompatible. MP@Alg-Ccm AuNPs also exhibited active targeting efficiency against MCF-7 cancer cells due to the presence of "antifolate" drug MTX. Thus MP@Alg-Ccm AuNPs may find potential application in targeted combination chemotherapy for the treatment of cancer. The study is also interesting from the synthetic point of view because, here generation of AuNPs was done using "green chemical" alginate and dual drug conjugated AuNPs were created in two simple reaction steps using "green solvent" water. PMID:26572330

  9. 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

  10. Choosing low-voltage switchgear for hydro plants

    SciTech Connect

    Clemen, D.M.

    1996-06-01

    Low-voltage switchgear performs a vital function in distributing power to auxiliary electrical loads within hydropower plants. With careful evaluation, plant owners and engineers can select equipment that provides needed protection and has useful secondary features. This article discusses the desirable features of low-voltage switchgear, including tripping functions, breaker ratings, protective functions, and overall quality.

  11. Evaluating the interaction between UCOE and DHFR-linked amplification and stability of recombinant protein expression.

    PubMed

    Betts, Zeynep; Croxford, Alexandra S; Dickson, Alan J

    2015-01-01

    Chinese hamster ovary (CHO) cells are widely used in the biopharmaceutical industry. In the creation of mammalian cell lines plasmid DNA carrying the gene-of-interest integrates randomly into the host cell genome, which results in variable levels of gene expression between cell lines due to gene silencing mechanisms. In addition, cell lines often show unstable protein production during long-term culture. This means that a large number of clones need to be screened in order to isolate stable, high producing cell lines making mammalian cell line development a long and laborious process. In this study an expression platform incorporating a Ubiquitous Chromatin Opening Element (UCOE; which are proposed to maintain chromatin in an open state) has been utilised for the expression of eGFP in CHO cells. Cell lines containing a UCOE vector, showed a significantly higher and more consistent eGFP expression than the non-UCOE cell lines without DHFR amplification. To further improve recombinant protein production cell lines were amplified with methotrexate (MTX). UCOE cell lines showed improved growth in MTX therefore amplification to 250 nM MTX was achieved following a one-step amplification procedure. However, non-UCOE cell lines showed higher levels of eGFP production following MTX amplification. In addition, UCOE cell lines did not improve stability during long-term culture in the absence of selective pressure. Stable eGFP production was achieved for all cell lines when MTX is present. Finally, UCOE cell lines displayed more consistent response to external stimuli than non-UCOE cell lines, suggesting that UCOE cell lines are less prone to clonal variability. PMID:25829363

  12. Numerical analysis for the evaluation of the stability of underground cavities in calcarenite interacting with buildings

    NASA Astrophysics Data System (ADS)

    Castellanza, Riccardo; Lollino, Piernicola; Oryem Ciantia, Matteo; di Prisco, Claudio; Crosta, Giovanni; Frigerio, Gabriele

    2013-04-01

    Soft and highly porous rocks such as tuffs and calcarenites are very common rocks. Due to their porous calcareous structure they are quite prone to water induced weathering mechanisms. Onshore and inland natural underground cavities are evident signs of these phenomena and of the effects in terms of failure. These materials have been largely employed in the past as building and ornamental stones and as sites to excavate underground cavities for different uses. The world famous Unesco site of "Sassi di Matera", the underground cavities in Canosa di Puglia and Gravina di Puglia , or the calcarenite cliff and natural caves of Polignano a Mare are the most representative cases. Nowadays, many of these are deteriorating because of weathering due to humidity, water infiltration, environmental pollution, and direct exposure to marine aerosols and meteoric water precipitations. In all these cases, a careful assessment of the safety of the built environment and a conscious identification of the safety measures cannot be separated from the analysis of the interaction between the cavities and the overlying buildings, and of the evolution and spatial distribution of the weathering processes. This contribute summarizes the authors' experience on the subject and suggests a methodological approach to quantitatively assess the stability of underground cavities. Starting from experimental evidences at micro and macroscale, the main debonding mechanisms have been taken into account in numerical models. The time-evolution scenarios of the weathering processes is introduced in three-dimensional numerical modelling. The intention is to provide a potentially useful tool for risk assessment in similar complex geomechanical situations.

  13. Increased voltage photovoltaic cell

    NASA Technical Reports Server (NTRS)

    Ross, B.; Bickler, D. B.; Gallagher, B. D. (inventors)

    1985-01-01

    A photovoltaic cell, such as a solar cell, is provided which has a higher output voltage than prior cells. The improved cell includes a substrate of doped silicon, a first layer of silicon disposed on the substrate and having opposite doping, and a second layer of silicon carbide disposed on the first layer. The silicon carbide preferably has the same type of doping as the first layer.

  14. Insulators for high voltages

    SciTech Connect

    Looms, J.S.T.

    1987-01-01

    This book describes electrical insulators for high voltage applications. Topics considered include the insulating materials, the manufacture of wet process porcelain, the manufacture of tempered glass, the glass-fibre core, the polymeric housing, the common problem - terminating an insulator, mechanical constraints, the physics of pollution flashover, the physics of contamination, testing of insulators, conclusions from testing, remedies for flashover, insulators for special cases, interference and noise, and the insulator of the future.

  15. 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.

  16. 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.

  17. High Voltage Connector

    SciTech Connect

    Kurita, C.H.; /Fermilab

    1987-03-06

    The originally designed high voltage connectors were to be made of brass. However, if treated like a Bellevile spring with the initially given dimensions, the stresses of the connector when crimped were calculated to be much higher than the yield stress of brass. Since the flange and outer diameters of the connector are to remain small, it was necessary to alter the other dimensions and choice of material in order to bring down the stresses applied to the connector.

  18. 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).

  19. Evaluation of the geological relationships to gas hydrate formation and stability

    SciTech Connect

    Not Available

    1985-01-01

    During the reported year we have enhanced our knowledge on and gained considerable experience in assessment of the gas hydrate resources in the offshore environments. Specifically, we have learned and gained experience in the following: Efficiently locating data sources, including published literature and unpublished information. We have established personal communication extremely critical in data accessability and acquisition. We have updated information pertinent to gas hydrate knowledge, also based on thorough study and evaluation of most Russian literature and additional publications in languages other than English. Besides critical evaluation of widely spread literature, in many cases our reports include previously unpublished information (e.g. BSRs from the Gulf of Mexico). The assessment of the gas resources potential associated with the gas hydrates, although in most cases at a low level of confidence, appears also very encouraging for further, more detailed, study. We are also confident that, because of the present reports' format, new data and a concept-oriented approach, the result of our study will be of strong interest to various industries, research institutions and numerous governmental agencies.

  20. 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.

  1. 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.

  2. Atomic structure of a voltage-dependent K+ channel in a lipid membrane-like environment.

    PubMed

    Long, Stephen B; Tao, Xiao; Campbell, Ernest B; MacKinnon, Roderick

    2007-11-15

    Voltage-dependent K+ (Kv) channels repolarize the action potential in neurons and muscle. This type of channel is gated directly by membrane voltage through protein domains known as voltage sensors, which are molecular voltmeters that read the membrane voltage and regulate the pore. Here we describe the structure of a chimaeric voltage-dependent K+ channel, which we call the 'paddle-chimaera channel', in which the voltage-sensor paddle has been transferred from Kv2.1 to Kv1.2. Crystallized in complex with lipids, the complete structure at 2.4 ångström resolution reveals the pore and voltage sensors embedded in a membrane-like arrangement of lipid molecules. The detailed structure, which can be compared directly to a large body of functional data, explains charge stabilization within the membrane and suggests a mechanism for voltage-sensor movements and pore gating. PMID:18004376

  3. Present Status of Josephson Voltage Metrology

    NASA Astrophysics Data System (ADS)

    Niemeyer, J.; Grimm, L.

    1988-01-01

    A description of the development and practical use of large Josephson series arrays for precision voltage measurements is given. The design and the measurement uncertainty of a standard instrument is described. The frequency stability is directly controlled by a radio signal of the long-wave transmitter DCF 77. The voltage standard does not need a screened room, and therefore it is ready for use independent of time and locality. It is shown that in 6 minutes a calibration of a Weston cell can be carried out with a total relative uncertainty (1 ?) of 12 × 10-10 at 0.1 Hz bandwidth. By decreasing the bandwidth a value of 6.5 × 10-10 is the ultimate limit for a single calibration.

  4. 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

  5. Experimental Evaluation of Journal Bearing Stability and New Gas Bearing Material

    NASA Technical Reports Server (NTRS)

    Keith, Theo G., Jr.; Dimofte, Florin

    2001-01-01

    It has been estimated that the noise levels in aircraft engine transmissions can be reduced by as much as 10 dB through the use of journal bearings. The potential benefits of lower noise levels include reduced wear, longer gear life and enhanced comfort for passengers and crew. Based on this concept the journal-thrust wave bearing was analyzed and its performance was evaluated. Numerical codes, developed over the past 30 years by Dr. Dimofte, were used to predict the performance of the bearing. The wave bearing is a fluid film bearing and therefore was analyzed using the Reynolds pressure equation. The formulation includes turbulent flow concepts and possesses a viscosity-temperature correction. The centrifugal growth of the bearing diameter and the deformation of the bearing under gear loads were also incorporated into the code. An experimental rig was developed to test the journal-thrust wave bearing.

  6. Evaluation of chloropyromorphite stability in the rhizosphere of and in a sand culture.

    PubMed

    Abbaspour, Ali; Arocena, Joselito M

    2012-01-01

    Chloropyromorphite (Pb(PO)Cl), CP, is the most stable lead (Pb) mineral under normal environmental conditions and precipitates in Pb-contaminated soils by addition of phosphorous (P). A sand culture experiment was conducted to evaluate the efficiency of and roots to dissolve CP in the presence and in the absence of P source. The results showed that the rhizosphere of the plants had lower soluble P and Pb compared with the bulk, which can be attributed to a higher pH in the rhizosphere. Mineralogical transformations of CP in the root surface of the plants including lanarkite (PbSO.PbO) has been confirmed by X-ray diffraction and scanning electron microscopy techniques. Decrease in soluble P in the rhizosphere as a consequence of P uptake by the plant roots may be a reason for CP dissolution. This study indicates that the dissolution of CP can be promoted by rhizosphere processes. PMID:23099944

  7. High Temperature Stability of Potassium Beta Alumina

    NASA Technical Reports Server (NTRS)

    Williams, R. M.; Kisor, A.; Ryan, M. A.

    1996-01-01

    None. From Objectives section: Evaluate the stability of potassium beta alumina under potassium AMTEC operating conditions. Evaluate the stability regime in which potassium beta alumina can be fabricated.

  8. Thermal Mechanical Stability of Single-Crystal-Oxide Refractive Concentrators Evaluated for High-Temperature Solar-Thermal Propulsion

    NASA Technical Reports Server (NTRS)

    Jacobson, Nathan S.; Jacobson, Nathan S.; Miller, Robert A.

    1999-01-01

    Recently, refractive secondary solar concentrator systems were developed for solar thermal power and propulsion (ref. 1). Single-crystal oxides-such as yttria-stabilized zirconia (Y2O3-ZrO2), yttrium aluminum garnet (Y3Al5O12, or YAG), magnesium oxide (MgO), and sapphire (Al2O3)-are candidate refractive secondary concentrator materials. However, the refractive concentrator system will experience high-temperature thermal cycling in the solar thermal engine during the sun/shade transition of a space mission. The thermal mechanical reliability of these components in severe thermal environments is of great concern. Simulated mission tests are important for evaluating these candidate oxide materials under a variety of transient and steady-state heat flux conditions. In this research at the NASA Lewis Research Center, a controlled heat flux test approach was developed for investigating the thermal mechanical stability of the candidate oxide. This approach used a 3.0-kW continuous-wave (wavelength, 10.6 mm) carbon dioxide (CO2) laser (ref. 2). The CO2 laser is especially well-suited for single-crystal thermal shock tests because it can directly deliver well-characterized heat energy to the oxide surfaces. Since the oxides are opaque at the 10.6-mm wavelength of the laser beam, the light energy is absorbed at the surfaces rather than transmitting into the crystals, and thus generates the required temperature gradients within the specimens. The following figure is a schematic diagram of the test rig.

  9. Evaluation of Cross-Protocol Stability of a Fully Automated Brain Multi-Atlas Parcellation Tool

    PubMed Central

    Liang, Zifei; He, Xiaohai; Ceritoglu, Can; Tang, Xiaoying; Li, Yue; Kutten, Kwame S.; Oishi, Kenichi; Miller, Michael I.; Mori, Susumu; Faria, Andreia V.

    2015-01-01

    Brain parcellation tools based on multiple-atlas algorithms have recently emerged as a promising method with which to accurately define brain structures. When dealing with data from various sources, it is crucial that these tools are robust for many different imaging protocols. In this study, we tested the robustness of a multiple-atlas, likelihood fusion algorithm using Alzheimer’s Disease Neuroimaging Initiative (ADNI) data with six different protocols, comprising three manufacturers and two magnetic field strengths. The entire brain was parceled into five different levels of granularity. In each level, which defines a set of brain structures, ranging from eight to 286 regions, we evaluated the variability of brain volumes related to the protocol, age, and diagnosis (healthy or Alzheimer’s disease). Our results indicated that, with proper pre-processing steps, the impact of different protocols is minor compared to biological effects, such as age and pathology. A precise knowledge of the sources of data variation enables sufficient statistical power and ensures the reliability of an anatomical analysis when using this automated brain parcellation tool on datasets from various imaging protocols, such as clinical databases. PMID:26208327

  10. Evaluation of the physicochemical and functional stability of diluted REMSIMA(®) upon extended storage-A study compliant with NHS (UK) guidance.

    PubMed

    Young, Benjamin L; Khan, Monika Ali; Chapman, Terry J; Parry, Richard; Connolly, Maria A; Watts, Andrew G

    2015-12-30

    A newly licensed biosimilar product containing infliximab as the active pharmaceutical ingredient has recently been marketed under the brand name Remsima(®). We have evaluated the stability of Remsima(®) diluted in sodium chloride solution and stored in polyolefin bags at 2-8°C using a range of techniques to assess the physico-chemical and functional integrity of the drug over time. The methods and techniques employed are fully compliant with NHS (UK) guidance for evaluating the stability of biologicals, enabling the data to be used for the application of an extended shelf-life to Remsima products in the UK, when prepared under a Section 10 exemption or a Specials Licence. The results clearly demonstrate physico-chemical and functional stability of the drug over the 7 day period of the study, when prepared as described here under aseptic conditions in accordance with the Summary of manufacturers Product Characteristics. PMID:26456268

  11. In Vivo Evaluation of Quantitative Percussion Diagnostics for Determining Implant Stability

    PubMed Central

    VanSchoiack, Lindsey R.; Shubayev, Veronica I.; Myers, Robert R.; Sheets, Cherilyn G.; Earthman, James C.

    2014-01-01

    Purpose A percussion instrument (Periometer®, Perimetrics LLC, Newport Beach, CA, USA) and rat model were used to test the hypothesis: percussion diagnostics provides reliable, reproducible indications of osseointegration. Materials and Methods Titanium implants were placed in femurs of 36 Sprague-Dawley rats. Each animal was assigned to one of six groups of six defined by one of three time points (2, 4, or 8 weeks post-placement) and one of two treatments (MMP inhibitor or vehicle). Percussion testing was conducted three times/subject at implant placement and at one of the time points. For each time point, there was an experimental group that received daily intraperitoneal injections of GM6001, and a control group that received no MMP inhibitor. The percussion data consisted of loss coefficient (LC) values that characterize energy dissipation. Statistical analysis was performed on the LC values for two animal groups using the paired Student t test to assess differences as a function of time, and the independent t test to compare mean LC for the study groups at sacrifice (?=0.05). Histological evaluation using the osteogenic CD40 protein marker was also performed. Results A nearly significant difference in mean LC at the 2-week time point was observed between the two treatments with the GM6001 group having the higher value (p = 0.053). There was a greater difference between the mean LC values for the 4-week GM6001 and vehicle groups (p = 0.001). The histological evidence for subjects in these two groups confirmed reduction of osteogenesis at the implant interface after administration of the MMP inhibitor. Conclusions Lower vehicle LC values relative to the GM6001 therapeutic group were observed, consistent with the effect MMP inhibition has on matrix remodeling at the implant bone interface. This finding in conjunction with histological observations confirms that osseointegration can be monitored using percussion diagnostics. PMID:24066319

  12. 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...

  13. Evaluating the Effect of Rainfall Infiltration on the Slope Stability of T16 tower of Taipei Mao-kong Gondola by Numerical Methods

    NASA Astrophysics Data System (ADS)

    RUNG, J.

    2013-12-01

    In this study, a series of rainfall-stability analyses were performed to simulate the failure mechanism and the function of remediation works of the down slope of T-16 tower pier, Mao-Kong gondola (or T-16 Slope) at the hillside of Taipei City using two-dimensional finite element method. The failure mechanism of T-16 Slope was simulated using the rainfall hyetograph of Jang-Mi typhoon in 2008 based on the field investigation data, monitoring data, soil/rock mechanical testing data and detail design plots of remediation works. Eventually, the numerical procedures and various input parameters in the analysis were verified by comparing the numerical results with the field observations. In addition, 48 hrs design rainfalls corresponding to 5, 10, 25 and 50 years return periods were prepared using the 20 years rainfall data of Mu-Zha rainfall observation station, Central Weather Bureau for the rainfall-stability analyses of T-16 Slope to inspect the effect of the compound stabilization works on the overall stability of the slope. At T-16 Slope, without considering the longitudinal and transverse drainages on the ground surface, there totally 4 types of stabilization works were installed to stabilize the slope. From the slope top to the slope toe, the stabilization works of T-16 Slope consists of RC-retaining wall with micro-pile foundation at the up-segment, earth anchor at the up-middle-segment, soil nailing at the middle-segment and retaining pile at the down-segment of the slope. The effect of each individual stabilization work on the slope stability under rainfall condition was examined and evaluated by raising field groundwater level.

  14. Computed voltage distributions around solar electric propulsion spacecraft

    NASA Technical Reports Server (NTRS)

    Stevens, N. J.

    1979-01-01

    The NASA Charging Analyzer Program is used to conduct preliminary computations of the voltage distributions around such large spacecraft in geomagnetic substorm environments at geosynchronous altitudes. Both a standard operating voltage (+ or - 150 volts on solar arrays) and direct-drive (+1200 volts on arrays) configurations are considered. Thruster-off simulations are computed for both operating voltage configurations while the effect of simulated thruster-on conditions are evaluated only for direct-drive configuration. These simulated thruster-on conditions are evaluated only for direct-drive configuration. These simulated thruster operations appear to alleviate surface charging.

  15. A Study on a Centralized Under-Voltage Load Shedding Scheme Considering the Load Characteristics

    NASA Astrophysics Data System (ADS)

    Deng, Jiyu; Liu, Junyong

    Under-voltage load shedding is an important measure for maintaining voltage stability.Aiming at the optimal load shedding problem considering the load characteristics,firstly,the traditional under-voltage load shedding scheme based on a static load model may cause the analysis inaccurate is pointed out on the equivalent Thevenin circuit.Then,the dynamic voltage stability margin indicator is derived through local measurement.The derived indicator can reflect the voltage change of the key area in a myopia linear way.Dimensions of the optimal problem will be greatly simplified using this indicator.In the end,mathematical model of the centralized load shedding scheme is built with the indicator considering load characteristics.HSPPSO is introduced to slove the optimal problem.Simulation results on IEEE-39 system show that the proposed scheme display a good adaptability in solving the under-voltage load shedding considering dynamic load characteristics.

  16. 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

  17. Evaluation of protein stability and in vitro permeation of lyophilized polysaccharides-based microparticles for intranasal protein delivery.

    PubMed

    Cho, Hyun-Jong; Balakrishnan, Prabagar; Chung, Suk-Jae; Shim, Chang-Koo; Kim, Dae-Duk

    2011-09-15

    Biocompatible microparticles prepared by lyophilization were developed for intranasal protein delivery. To test for the feasibility of this formulation, stability of the incorporated protein and enhancement of in vitro permeation across the nasal epithelium were evaluated. Lyophilization was processed with hydroxypropylmethylcellulose (HPMC) or water soluble chitosan (WCS) as biocompatible polymers, hydroxypropyl-?-cyclodextrin (HP-?-CD) and d-alpha-tocopheryl poly(ethylene glycol 1000) succinate (TPGS 1000) as permeation enhancers, sugars as cryoprotectants and lysozyme as the model protein. As a result, microparticles ranging from 6 to 12?m were developed where the maintenance of the protein conformation was verified by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), circular dichroism and fluorescence intensity detection. Moreover, in vitro bioassay showed that the lysozyme activity was preserved during the preparation process while exhibiting less cytotoxicity in primary human nasal epithelial (HNE) cells. Results of the in vitro release study revealed slower release rate in these microparticles compared to that of the lysozyme itself. On the other hand, the in vitro permeation study exhibited a 9-fold increase in absorption of lysozyme when prepared in lyophilized microparticles with HPMC, HP-?-CD and TPGS 1000 (F4-2). These microparticles could serve as efficient intranasal delivery systems for therapeutic proteins. PMID:21703339

  18. Fiber Optic High Voltage Probe

    SciTech Connect

    Matthew J. Heino

    1999-08-01

    We developed a fiber coupled sensor to measure High Voltage directly using only light as the probe. We use the Pockles effect in lithium niobate crystal which will induce a phase shift in a laser beam that varies according to applied voltage. This can then be transformed into a modulation of beam intensity by polarizers, interferometery, or waveguide coupling. No voltage dividers are necessary, nor is any physical connection. This is accompanied by taking advantage of the structure of the power system itself, using voltage planes and dielectric insulation already present as the capacitive voltage divider. We hypothesize a bandwidth from GHz to DC. Such a system could be used in any application that calls for isolated and unobtrusive voltage sensing.

  19. Onset of superconductivity in a voltage-biased normal-superconducting-normal microbridge

    E-print Network

    Serbyn, Maksym

    We study the stability of the normal state in a mesoscopic NSN junction biased by a constant voltage V with respect to the formation of the superconducting order. Using the linearized time-dependent Ginzburg-Landau equation, ...

  20. Evaluation of the cytotoxic effects of PLGA coated iron oxide nanoparticles as a carrier of 5- fluorouracil and mega-voltage X-ray radiation in DU145 prostate cancer cell line.

    PubMed

    Hajikarimi, Zahra; Khoei, Samideh; Khoee, Sepideh; Mahdavi, Seied Rabi

    2014-12-01

    The purpose of this study was to investigate the uptake and cytotoxic effects of magnetic poly lactic-co-glycolic acid (PLGA)-coated iron oxide nanoparticles as a carrier of 5-fluorouracil (5-FU) and X-ray on the level of proliferation capacity of DU145 prostate carcinoma cell line in monolayer culture. Following monolayer culture, DU 145 cells were treated with different concentrations of 5-FU or 5-FU loaded nanoparticles for 24 h and 2Gy X-ray (6 Mega-voltage (MV)). The rate of nanoparticles penetration was then measured using atomic adsorption spectroscopy (AAS). The cytotoxicity effect of these nanoparticles with/ without X-ray radiation was evaluated using colony formation assay. Spectroscopy results showed that iron content and therefore the cellular uptake of 5-FU loaded nanoparticles increased with increasing nanoparticle concentrations. Further, the proliferation capacity of the cells decreased with the increase of 5-FU and 5- FU loaded nanoparticle concentrations in combination with X-ray radiation. However the extent of reduction in colony number following treatment with 5-FU-loaded nanoparticles in combination with 2Gy of megavoltage X-ray radiation was significantly more than for free 5-FU. Thus, drug-loaded nanoparticles could deliver 5-FU more efficiently into the cells. PLGA coated iron oxide nanoparticles are therefore effective drug delivery vehicles for 5-FU. PLGA coated iron oxide nanoparticles are biocompatible and this coating is an appropriate surface that can penetrate into the cells. PMID:25051558

  1. Low voltage and high contrast blue phase liquid crystal with red-shifted Bragg reflection

    E-print Network

    Wu, Shin-Tson

    Low voltage and high contrast blue phase liquid crystal with red-shifted Bragg reflection Jin Yan,1 demonstrated a low voltage and high contrast polymer-stabilized blue phase liquid crystal (BPLC) by shifting the Bragg reflection to a red wavelength. To retain high contrast ratio, a left- handed BPLC is sandwiched

  2. Voltage reduction cuts appliance loads

    SciTech Connect

    Not Available

    1980-01-15

    An analysis of the effect of circuit-voltage reduction on individual appliances shows that, for most appliances, there is a definite reduction in load when voltage is reduced. Depending on the type of appliance, there may be a reduction in energy usage. Data are graphically shown for a television, clothes washer, toaster oven, and refrigerators. Additional data are presented on the efficiencies of some small induction motors as a function of voltage and load.

  3. 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.

  4. High voltage feedthrough bushing

    DOEpatents

    Brucker, John P. (Espanola, NM)

    1993-01-01

    A feedthrough bushing for a high voltage diode provides for using compression sealing for all sealing surfaces. A diode assembly includes a central conductor extending through the bushing and a grading ring assembly circumferentially surrounding and coaxial with the central conductor. A flexible conductive plate extends between and compressively seals against the central conductor and the grading ring assembly, wherein the flexibility of the plate allows inner and outer portions of the plate to axially translate for compression sealing against the central conductor and the grading ring assembly, respectively. The inner portion of the plate is bolted to the central conductor for affecting sealing. A compression beam is also bolted to the central conductor and engages the outer portion of the plate to urge the outer portion toward the grading ring assembly to obtain compression sealing therebetween.

  5. High voltage isolation transformer

    NASA Technical Reports Server (NTRS)

    Clatterbuck, C. H.; Ruitberg, A. P. (inventors)

    1985-01-01

    A high voltage isolation transformer is provided with primary and secondary coils separated by discrete electrostatic shields from the surfaces of insulating spools on which the coils are wound. The electrostatic shields are formed by coatings of a compound with a low electrical conductivity which completely encase the coils and adhere to the surfaces of the insulating spools adjacent to the coils. Coatings of the compound also line axial bores of the spools, thereby forming electrostatic shields separating the spools from legs of a ferromagnetic core extending through the bores. The transformer is able to isolate a high constant potential applied to one of its coils, without the occurrence of sparking or corona, by coupling the coatings, lining the axial bores to the ferromagnetic core and by coupling one terminal of each coil to the respective coating encasing the coil.

  6. Substation voltage upgrading

    SciTech Connect

    Panek, J.; Elahi, H.; Lux, A.; Imece, A.F. . Power Systems Engineering Dept.); LaPanse, R.A.; Stewart, J.R. )

    1992-04-01

    This report addresses specific issues to support sound yet not unduly conservative uprating practices for substations. The main parts of the report cover the insulation withstand and overvoltage protection aspects, environmental measurements, reliability criteria, and industry experience. First the insulation design concerns are addressed. Substation stress by a backflashover of the line insulation due to lightning in the vicinity of the substation is recognized as a critical stress. A representative part of a 550 kV BIL substation was erected at the EPRI High Voltage Transmission Research Center, where also a special test circuit was assembled to produce a fast front, slow tail (0.2/200 {mu}s) wave. The substation as well as some special configurations were tested for line-to-ground and line-to-line withstand. Computer studies were performed to complement the test results. A number of important conclusions was reached. The most prominent result in that the high frequency oscillations, as caused by reflections within the substation, do not effect the Critical Flashover Voltage (CFO). The present practice, based on the highest peak is therefore very conservative. The slow tail of the wave appears to dictate the CFO. An arrester model for computer studies to represent very fast as well as slow phenomena was derived. It is based on full scale arrester test data, made available in this project. The computer program to calculate arrester model parameters is also a part of the report. The electric environmental measurements are reported for the tested substation at the HVTRC and for the uprated substation of Public Service Company of Colorado, both before and after the uprating. The performance is satisfactory when corona free hardware is used. Insulation design criteria are analyzed based on substation reliability, the system viewpoint and consequences of the failure. Utility experience with uprated substations is reviewed.

  7. Time scales of bias voltage effects in FE/MgO-based magnetic tunnel junctions with voltage-dependent perpendicular anisotropy

    NASA Astrophysics Data System (ADS)

    Lytvynenko, Ia. M.; Hauet, T.; Montaigne, F.; Bibyk, V. V.; Andrieu, S.

    2015-12-01

    Interplay between voltage-induced magnetic anisotropy transition and voltage-induced atomic diffusion is studied in epitaxial V/Fe (0.7 nm)/ MgO/ Fe(5 nm)/Co/Au magnetic tunnel junction where thin Fe soft electrode has in-plane or out-of-plane anisotropy depending on the sign of the bias voltage. We investigate the origin of the slow resistance variation occurring when switching bias voltage in opposite polarity. We demonstrate that the time to reach resistance stability after voltage switching is reduced when increasing the voltage amplitude or the temperature. A single energy barrier of about 0.2 eV height is deduced from temperature dependence. Finally, we demonstrate that the resistance change is not correlated to a change in soft electrode anisotropy. This conclusion contrasts with observations recently reported on analogous systems.

  8. 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

  9. Planned Variation in Preanalytical Conditions to Evaluate Biospecimen Stability in the National Children’s Study (NCS)

    PubMed Central

    Mechanic, Leah; Mendez, Armando; Merrill, Lori; Rogers, John; Layton, Marnie; Todd, Deborah; Varanasi, Arti; O’Brien, Barbara; Meyer, William A.; Zhang, Ming; Schleicher, Rosemary L.; Moye, Jack

    2014-01-01

    BACKGROUND Preanalytical conditions encountered during collection, processing, and storage of biospecimens may influence laboratory results. The National Children’s Study (NCS) is a planned prospective cohort study of 100,000 families to examine the influence of a wide variety of exposures on child health. In developing biospecimen collection, processing, and storage procedures for the NCS, we identified several analytes of different biochemical categories for which it was unclear to what extent deviations from NCS procedures could influence measurement results. METHODS A pilot study was performed to examine effects of preanalytic sample handling conditions (delays in centrifugation, freezing delays, delays in separation from cells, additive delay, and tube type) on concentrations of eight different analytes. 2,825 measurements were made to assess 15 unique combinations of analyte and handling conditions in blood collected from 151 women of childbearing age (?20 individuals per handling condition). RESULTS The majority of analytes were stable under the conditions evaluated. However, levels of plasma interleukin-6 and serum insulin were decreased in response to sample centrifugation delays of up to 5.5 hours post collection (P<0.0001). In addition, delays in freezing centrifuged plasma samples (comparing 24, 48 and 72 hours to immediate freezing) resulted in increased levels of adrenocorticotropic hormone (P=0.0014). CONCLUSIONS Determining stability of proposed analytes in response to preanalytical conditions and handling helps to ensure high-quality specimens for study now and in the future. The results inform development of procedures, plans for measurement of analytes, and interpretation of laboratory results. PMID:23924524

  10. Evaluation of Nucleic Acid Stabilization Products for Ambient Temperature Shipping and Storage of Viral RNA and Antibody in a Dried Whole Blood Format

    PubMed Central

    Dauner, Allison L.; Gilliland, Theron C.; Mitra, Indrani; Pal, Subhamoy; Morrison, Amy C.; Hontz, Robert D.; Wu, Shuenn-Jue L.

    2015-01-01

    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

  11. Evaluation of Stability and Transient Characteristics of ABWR-II Large Bundle Core and SSR Influence for Transient phenomena by TRACG Code

    SciTech Connect

    Masao, Chaki; Hideo, Soneda; Shinya, Mizokami; Hideya, Kitamura; Kouji, Hiraiwa; Takanori, Fukahori; Andersen, Jens G.

    2004-07-01

    The next generation ABWR, the ABWR-II, has been under development for more than a decade in Japan. Among various features newly adopted for the ABWR-II, a 1.5 times lager fuel bundle is notable. This bundle design makes it possible to increase the total number of fuel rods in the core while minimizing the reactor pressure vessel size increase. As a result, the void coefficient is more negative due to the harder neutron spectrum since a smaller hydrogen-to uranium (H/U) ratio with fuel inventory increase makes the neutron spectrum harder. This more negative void coefficient affects the stability and transient characteristics of the ABWR-II plant. We have evaluated the stability and transient characteristics by using analysis codes and proven that these characteristics do not affect the realization of the ABWR-II large bundle core concept. Furthermore, we have evaluated the influences for the stability and transient phenomena by using spectral shift rods (SSRs) for the ABWR-II core. The analytical results show that the use of SSRs increases the design margin for the core stability. Regarding transient phenomena, the analyses by the TRACG code show that the influence of using SSRs is very small and do not affect the realization of the ABWR-II plant. In addition, the sensitivity analyses with the TRACG code show that design parameters of SSRs, inlet hole diameter of ascending path etc, are not very sensitive for the transient phenomena. (authors)

  12. Strain-optic voltage monitor

    SciTech Connect

    Weiss, J.D.

    1995-12-31

    A voltage monitor which uses the shift in absorption edge of crystalline material to measure strain resulting from electric field-induced deformation of piezoelectric or electrostrictive material, providing a simple and accurate means for measuring voltage applied either by direct contact with the crystalline material or by subjecting the material to an electric field.

  13. Voltage sensor and dielectric material

    DOEpatents

    Yakymyshyn, Christopher Paul; Yakymyshyn, Pamela Jane; Brubaker, Michael Allen

    2006-10-17

    A voltage sensor is described that consists of an arrangement of impedance elements. The sensor is optimized to provide an output ratio that is substantially immune to changes in voltage, temperature variations or aging. Also disclosed is a material with a large and stable dielectric constant. The dielectric constant can be tailored to vary with position or direction in the material.

  14. Current vs. Voltage Feedback Amplifiers

    E-print Network

    Papavassiliou, Christos

    Current vs. Voltage Feedback Amplifiers One question continuously troubles the analog design engi- neer: 'Which amplifier topology is better for my application, current feedback or voltage feedback) are not apparent. Today's CFB and VFB amplifiers have comparable performance, but there are cer- tain unique

  15. 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.

  16. Active Power Rescheduling for Avoiding Voltage Collapse Using Modified Bare Bones Particle Swarm Optimization

    NASA Astrophysics Data System (ADS)

    Arya, Rajesh; Purey, Pradeep

    2015-06-01

    MW-generation rescheduling is being considered for voltage stability improvement under stressed operating condition. At times it can avoid voltage collapse. This paper describes an algorithm for determination of optimum MW-generation participation pattern for static voltage stability margin enhancement. The optimum search direction has been obtained by employing modified bare born particle swarm optimization technique. Optimum search direction is based on maximization of distance to point of collapse in generation space. Developed algorithm has been implemented on a standard 25 bus test system. Results obtained have been compared with those obtained using standard particle swarm optimization.

  17. 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,...

  18. Unlikely Combination of Experiments with a Novel High-Voltage CIGS Photovoltaic Array (Presentation)

    SciTech Connect

    del Cueto, J. A.; Sekulic, B. R.

    2006-05-01

    The goals of this study are to: (1) parameterize current-voltage (I-V) performance over a wide range of illumination and temperatures: (a) 50-1150 W/m{sup 2} irradiance, 5-65 C; (b) obtain array temperature coefficients; and (c) quantify energy production; (2) investigate high-voltage leakage currents from the CIS modules in a high-voltage array: determine dependence on moisture, temperature, and voltage bias and ascertain corrosion problems if any; and (3) study long-term power and energy production stability.

  19. Stability of CIGS solar cells and component materials evaluated by a step-stress accelerated degradation test method

    NASA Astrophysics Data System (ADS)

    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 15°C and then a 15% relative humidity (RH) increment step, beginning from 40°C/40%RH (T/RH = 40/40) to 85°C/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.

  20. 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.

  1. Evaluating the Stability of RNA-Seq Transcriptome Profiles and Drug-Induced Immune-Related Expression Changes in Whole Blood.

    PubMed

    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

  2. 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

  3. 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.

  4. Rock Slope Stability Evaluation in a Steep-Walled Canyon: Application to Elevator Construction in the Yunlong River Valley, Enshi, China

    NASA Astrophysics Data System (ADS)

    Xiao, Lili; Chai, Bo; Yin, Kunlong

    2015-09-01

    A passenger elevator is to be built on a nearly vertical slope in the National Geological Park in Enshi, Hubei province, China. Three steps comprise the construction: excavating the slope toe for the elevator platform, building the elevator on the platform, and affixing the elevator to the slope using anchors. To evaluate the rock slope stability in the elevator area and the safety of the elevator construction, we applied three techniques: qualitative analysis, formula calculation, and numerical simulation methods, based on field investigation and parameter selection, and considering both wet and dry conditions, pre- and post-construction. Qualitative stability factors for sliding and falling were calculated using the limit equilibrium method; the results show that the slope as a whole is stable, with a few unstable blocks, notably block BT1. Formula-based stability factors were calculated for four sections on block BT1, revealing the following: anchors will decrease the stability of certain rock pieces; the lowest average stability factor after anchoring will be K f = 1.36 in wet conditions; block BT1 should be reinforced during elevator construction, up to a first-class slope stability factor of K f = 1.40; and the slope as a whole is stable. Numerical simulation using FLAC3D indicated that the stress distribution will reach equilibrium for all steps before and after construction, and that the factor of safety (FOS) is within the general slope safety range (FOS > 1.05). We suggest that unstable pieces in block BT1 be reinforced during construction to a first-class slope safety range (FOS > 1.3), and that deformation monitoring on the slope surface be implemented.

  5. 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.

  6. Voltage Sensors Monitor Harmful Static

    NASA Technical Reports Server (NTRS)

    2009-01-01

    A tiny sensor, small enough to be worn on clothing, now monitors voltage changes near sensitive instruments after being created to alert Agency workers to dangerous static buildup near fuel operations and avionics. San Diego s Quasar Federal Systems received a Small Business Innovation Research (SBIR) contract from Kennedy Space Center to develop its remote voltage sensor (RVS), a dime-sized electrometer designed to measure triboelectric changes in the environment. One of the unique qualities of the RVS is that it can detect static at greater distances than previous devices, measuring voltage changes from a few centimeters to a few meters away, due to its much-improved sensitivity.

  7. 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.

  8. 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.

  9. Transformer regulated self-stabilizing chopper

    NASA Technical Reports Server (NTRS)

    Raposa, F. L. (inventor)

    1969-01-01

    A self-stabilizing voltage regulator is described. Direct current voltage regulation employing a series transistor rendered conductive during various portions of a cycle is controlled by saturation of an autotransformer. The constant volt-second capacity of the transformer provides conduction time inverse to the input voltage whereby average output voltage is maintained constant. Conduction commenced in response to short gate signals, and resistor feedback for degenerative turn-off of the transistor was after transformer saturation. Standard output filters are also included.

  10. Voltage-Boosting Driver For Switching Regulator

    NASA Technical Reports Server (NTRS)

    Trump, Ronald C.

    1990-01-01

    Driver circuit assures availability of 10- to 15-V gate-to-source voltage needed to turn on n-channel metal oxide/semiconductor field-effect transistor (MOSFET) acting as switch in switching voltage regulator. Includes voltage-boosting circuit efficiently providing gate voltage 10 to 15 V above supply voltage. Contains no exotic parts and does not require additional power supply. Consists of NAND gate and dual voltage booster operating in conjunction with pulse-width modulator part of regulator.

  11. 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.

  12. A Matter of Quantum Voltages

    SciTech Connect

    Sellner, Bernhard; Kathmann, Shawn M.

    2014-11-14

    Voltages inside matter are relevant to crystallization, materials science, biology, catalysis, and aqueous chemistry. Electron holography is able to measure the variation of voltages in matter and modern supercomputers allow the calculation of quantum voltages with practically unlimited spatial and temporal resolution of bulk systems. Of particular interest is the Mean Inner Potential (Vo) - the spatial average of these voltages. Voltages are very sensitive to the distribution of electrons and provide metrics to understand interactions in condensed phases. In the present study, we find excellent agreement with measurements of Vo for vitrified water and salt crystals and demonstrate the impact of covalent and ionic bonding as well as intermolecular/atomic interactions. Furthermore, we predict Vo as well as the fluctuations of these voltages in aqueous NaCl electrolytes and characterize the changes in their behavior as the resolution increases below the size of atoms. This work was supported by the U.S. Department of Energy, Office of Basic Energy Sciences, Division of Chemical Sciences, Geosciences & Biosciences. Pacific Northwest National Laboratory (PNNL) is a multiprogram national laboratory operated for DOE by Battelle. This research used resources of the National Energy Research Scientific Computing Center, which is supported by the Office of Science of the U.S. Department of Energy under Contract No. DE-AC02-05CH11231.

  13. Evaluation of the geological relationships to gas hydrate formation and stability. Second annual technical progress report, October 1, 1985--September 30, 1986

    SciTech Connect

    Not Available

    1986-12-31

    Although there are many publications pertaining to gas hydrates, their formation and stability in various geological conditions are poorly known. Therefore, for the same reasons and because of the very broad scope of our research, limited amount and extremely dispersed information, the study regions are very large. Moreover, almost without exception the geological environments controlling gas hydrates formation and stability of the studied regions are very complex. The regions studied (completed and partially completed - total 17 locations) during the reporting period, particularly the Gulf of Mexico and the Middle America Trench, are the most important in this entire research project. In the past, both of these regions have been extensively studied, the presence of gas hydrates confirmed and samples recovered. In our investigation it was necessary not only to review all previous data and interpretations, but to do a thorough analysis of the basins, and a critical evaluation of an previously reported and publicly available but not published information.

  14. Continuous sagittal radiological evaluation of stair-climbing in cruciate-retaining and posterior-stabilized total knee arthroplasties using image-matching techniques.

    PubMed

    Hamai, Satoshi; Okazaki, Ken; Shimoto, Takeshi; Nakahara, Hiroyuki; Higaki, Hidehiko; Iwamoto, Yukihide

    2015-05-01

    In this study, we evaluated the in vivo kinematics of stair-climbing after posterior stabilized (PS) and cruciate retaining (CR) total knee arthroplasty (TKA) using radiographic-based image-matching techniques. Mid-flexion anteroposterior stability was demonstrated in all knees after CR TKA. However, paradoxical femoral translation at low flexion angles was seen in both designs. The post-cam mechanism did not function after PS TKA. Larger posterior tibial slope in PS TKA was linked to forward sliding of the femur at mid-flexion and unintended anterior tibial post impingement at knee extension. CR TKA is more sagittally stable in mid-flexion during stair climbing and attention must be given to minimize posterior tibial slope when using late cam-post engaging PS TKA designs. PMID:25618811

  15. Absorption Voltages and Insulation Resistance in Ceramic Capacitors with Cracks

    NASA Technical Reports Server (NTRS)

    Teverovsky, Alexander

    2014-01-01

    Time dependence of absorption voltages (V(sub abs)) in different types of low-voltage X5R and X7R ceramic capacitors was monitored for a maximum duration of hundred hours after polarization. To evaluate the effect of mechanical defects on V(sub abs)), cracks in the dielectric were introduced either mechanically or by thermal shock. The maximum absorption voltage, time to roll-off, and the rate of voltage decrease are shown to depend on the crack-related leakage currents and insulation resistance in the parts. A simple model that is based on the Dow equivalent circuit for capacitors with absorption has been developed to assess the insulation resistance of capacitors. Standard measurements of the insulation resistance, contrary to the measurements based on V(sub abs)), are not sensitive to the presence of mechanical defects and fail to reveal capacitors with cracks.

  16. Accelerator System Development at High Voltage Engineering

    SciTech Connect

    Klein, M. G.; Gottdang, A.; Haitsma, R. G.; Mous, D. J. W.

    2009-03-10

    Throughout the years, HVE has continuously extended the capabilities of its accelerator systems to meet the rising demands from a diverse field of applications, among which are deep level ion implantation, micro-machining, neutron production for biomedical research, isotope production or accelerator mass spectrometry. Characteristic for HVE accelerators is the coaxial construction of the all solid state power supply around the acceleration tubes. With the use of solid state technology, the accelerators feature high stability and very low ripple. Terminal voltages range from 1 to 6 MV for HVE Singletrons and Tandetrons. The high-current versions of these accelerators can provide ion beams with powers of several kW. In the last years, several systems have been built with terminal voltages of 1.25 MV, 2 MV and 5 MV. Recently, the first system based on a 6 MV Tandetron has passed the factory tests. In this paper we describe the characteristics of the HVE accelerator systems and present as example recent systems.

  17. Evaluation and measurement of the experimental gamma-ray peak broadenings and recovery times in a gain stabilized system

    NASA Astrophysics Data System (ADS)

    O'Connor, D.; Knoll, G.; Ziff, R.

    1994-12-01

    Peak broadenings induced by gain wander in a gain stabilized system were measured and found to approximate values determined from prediction techniques and a system simulation. An equation is derived for the recovery time of the system; its predictions are validated by experimental measurements.

  18. 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...

  19. PMU-Aided Voltage Security Assessment for a Wind Power Plant: Preprint

    SciTech Connect

    Jiang, H.; Zhang, Y. C.; Zhang, J. J.; Muljadi, E.

    2015-04-08

    Because wind power penetration levels in electric power systems are continuously increasing, voltage stability is a critical issue for maintaining power system security and operation. The traditional methods to analyze voltage stability can be classified into two categories: dynamic and steady-state. Dynamic analysis relies on time-domain simulations of faults at different locations; however, this method needs to exhaust faults at all locations to find the security region for voltage at a single bus. With the widely located phasor measurement units (PMUs), the Thevenin equivalent matrix can be calculated by the voltage and current information collected by the PMUs. This paper proposes a method based on a Thevenin equivalent matrix to identify system locations that will have the greatest impact on the voltage at the wind power plant’s point of interconnection. The number of dynamic voltage stability analysis runs is greatly reduced by using the proposed method. The numerical results demonstrate the feasibility, effectiveness, and robustness of the proposed approach for voltage security assessment for a wind power plant.

  20. 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.

  1. Properties of UN Sintered by High Voltage Electric Discharge Consolidation

    NASA Astrophysics Data System (ADS)

    Yurlova, M.; Tarasov, B.; Shornikov, D.; Grigoryev, E.; Olevsky, E.

    In the present work, the opportunity of the consolidation of uranium nitride tablets by high voltage electric discharge consolidation (HVEDC) is considered. It is shown that the consolidation by HVEDC allows the prevention of the expansion of uranium nitride powders and renders pellets with relative density of up to 97%. The thermal stability of the obtained samples has been investigated. The analysis of the microstructure of the processed samples indicates the retention of the initial powder structure

  2. Voltage, energy and power in electric circuits

    E-print Network

    Haase, Markus

    Voltage, energy and power in electric circuits Science teaching unit #12;Disclaimer The Department-2008DVD-EN Voltage, energy and power in electric circuits #12;#12;© Crown copyright 2008 1The National Strategies | Secondary Voltage, energy and power in electric circuits 00094-2008DVD-EN Contents Voltage

  3. Evaluation of sulfidic mine tailings solidified/stabilized with cement kiln dust and fly ash to control acid mine drainage

    SciTech Connect

    Nehdi, M.; Tariq, A.

    2008-11-15

    In the present research, industrial byproducts, namely, cement kiln dust (CKD) and Class C fly ash (FAC) have been used as candidate materials along with the partial addition of sulfate-resistant cement (SRC) in the Stabilization/solidification of polymetallic sulfidic mine tailings (MT). The effectiveness of S/S was assessed by comparing laboratory experimental values obtained from unconfined compressive strength, hydraulic conductivity and leaching propensity tests of S/S samples with regulatory standards for safe surface disposal of such wastes. Despite general regulatory compliance of compressive strength and hydraulic conductivity, some solidified/stabilized-cured matrices were found unable to provide the required immobilization of pollutants. Solidified/stabilized and 90-day cured mine tailings specimens made with composite binders containing (10% CKD + 10% FAC), (5% SRC + 15% FAC) and (5% SRC + 5% CKD + 10% FAC) significantly impaired the solubility of all contaminants investigated and proved successful in fixing metals within the matrix, in addition to achieving adequate unconfined compressive strength and hydraulic conductivity values, thus satisfying USEPA regulations. Laboratory investigations revealed that, for polymetallic mining waste, leachate concentrations are the most critical factor in assessing the effectiveness of S/S technology.

  4. Synthesis and Bio-Evaluation of New (18) F-Labeled Pyridaben Analogs with Improved Stability for Myocardial Perfusion Imaging in Mice.

    PubMed

    Mou, Tiantian; Zhao, Zuoquan; Zhang, Pu; Fang, Wei; Peng, Cheng; Lu, Jie; Wang, Qian; Ma, Yunchuan; Zhang, Xianzhong

    2015-09-01

    To improve the stability of (18) F-labeled pyridaben analogs for myocardial perfusion imaging, three new analogs of pyridaben ([(18) F]FPTP2, [(18) F]FPTP-P2, and [(18) F]FPTP-P3) were synthesized with 'side chain' modifications. The radiolabeled tracers and corresponding non-radioactive compounds were obtained by substituting tosyl group with (18/19) F. The effect of structure modification on myocardial targeting and physicochemical properties of new tracers were evaluated in vitro and in vivo. The total radiosynthesis time of these tracers was approximately 70-90 min with high decay-corrected radiochemical yields (36-65%) and good radiochemical purity (> 98%). These lipophilic tracers exhibited obvious improved stability in water. Studies of their biodistribution in normal Kunming mice demonstrated that [(18) F]FPTP2 exhibited very high initial heart uptake (39.70 ± 2.81 %ID/g at 2 min after injection) and low background in the liver, blood, and soft tissues. The heart-to-liver, heart-to-lung, and heart-to-blood ratios were 3.59, 19.34, and 67.34 at 15 min postinjection, respectively. Favorable myocardial targeting property and remarkable improvement of stability of [(18) F]FPTP2 suggest that the substitution of the phenyl 'sidechain' with other non-phenyl rings has no effect on the myocardial targeting property of (18) F-labeled pyridaben analogs. PMID:25529021

  5. Evaluation of metal oxide and carbonate nanoparticle stability in soybean oil: Implications for controlled release of alkalinity during subsurface remediation

    NASA Astrophysics Data System (ADS)

    Ramsburg, C. A.; Leach, O. I.; Sebik, J.; Muller, K.

    2011-12-01

    Traditional methods for adjusting groundwater pH rely on injection of aqueous solutes and therefore, amendment distribution is reliant upon aqueous phase flow and transport. This reliance can limit mixing and sustention of amendments within the treatment zone. Oil-in-water emulsions offer an alternative for amendment delivery - one that has potential to enhance control of the distribution and release of buffering agents within the subsurface. Focus here is placed on using metal oxide and carbonate nanoparticles to release alkalinity from soybean oil, a common dispersed phase within emulsions designed to support remediation activities. Batch reactor systems were employed to examine the influence of dispersed phase composition on particle stability and solubility. The stability of uncoated MgO and CaCO3 particles in unmodified soybean oil was explored in a series of sedimentation studies conducted at solid loadings of 0.05, 0.1, and 0.2% mass. Three nominal sizes of MgO particles were examined (20, 50, and 100 nm) and one CaCO3 particle size (60 nm). Results from sedimentation studies conducted over four hours suggest that the viscosity of the soybean oil imparts a kinetic stability, for all sizes of the uncoated MgO and CaCO3 nanoparticles, which is sufficient time for particle encapsulation within oil-in-water emulsions. Based upon these results, the sedimentation of the 50 nm and 100 nm MgO, and 60 nm CaCO3 particles was assessed over longer durations (?72 hr). Results from these stability tests suggest that the 50 nm and 100 nm MgO particles have greater kinetic stability than the 60 nm CaCO3. Batch studies were also used to assess the influence of n-butanol, a co-solvent hypothesized to aid in controlling the rate of alkalinity release, on phase behavior and metal (Mg2+ and Ca2+) solubility. Phase behavior studies suggest that n-butanol has a limited region of miscibility within the soybean oil-water system. Use of n-butanol and water within this region of miscibility was found to increase the dielectric constant of the oil from 3.3 to 5.2. Results of solubility studies suggest that oil phase polarity may increase Ca2+ solubility, though effects were less discernable for Mg2+. These results are being employed to assess the distribution of carbonate and metal oxide particles between the soybean oil and aqueous phase. Subsequent studies will focus on exploring the influence of co-solvents on the rate of alkalinity release from oil-in-water emulsions.

  6. Voltage-Gated Hydrophobic Nanopores

    SciTech Connect

    Lavrik, Nickolay V

    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.

  7. 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.

  8. Frequency stabilization in nonlinear MEMS and NEMS oscillators

    DOEpatents

    Lopez, Omar Daniel; Antonio, Dario

    2014-09-16

    An illustrative system includes an amplifier operably connected to a phase shifter. The amplifier is configured to amplify a voltage from an oscillator. The phase shifter is operably connected to a driving amplitude control, wherein the phase shifter is configured to phase shift the amplified voltage and is configured to set an amplitude of the phase shifted voltage. The oscillator is operably connected to the driving amplitude control. The phase shifted voltage drives the oscillator. The oscillator is at an internal resonance condition, based at least on the amplitude of the phase shifted voltage, that stabilizes frequency oscillations in the oscillator.

  9. Low Voltage Spatial Light Modulator

    SciTech Connect

    Papavasiliou, A

    2003-02-19

    This project studied the feasibility of a Low-Voltage actuator technology that promises to reduce the switched voltage requirements and linearize the response of spatial light modulators. We created computer models that demonstrate substantial advantages offered by this technology, and fabricated and tested those devices. SLMs are electro-optic devices for modulating the phase, amplitude or angle of light beams, laser or other. Applications for arrays of SLMs include turbulence correction for high-speed optical communications, imaging through distorting media, input devices for holographic memories, optical manipulation of DNA molecules, and optical computers. Devices based on micro electro-mechanical systems (MEMS) technology have recently become of special interest because of their potential for greatly improved performance at a much lower cost than piezoelectric or liquid crystal based devices. The new MEMS-based SLM devices could have important applications in high-speed optical communication and remote optical sensing, in support of DoD and DOE missions. Virtually all previously demonstrated MEMS SLMs are based on parallel-plate capacitors where an applied voltage causes a mirror attached to a suspended electrode to move towards a fixed electrode. They require relatively high voltages, typically on the order of 100 V, resulting in (1) large transistor sizes, available only from specialized foundries at significant cost and limiting the amount/sophistication of electronics under each SLM pixel, and (2) large power dissipation/area, resulting in a heat removal issue because of the optical precision required ({approx} 1/50-th of a wavelength). The actuator described in this process uses an advanced geometry that was invented at LLNL and is currently still proprietary. The new geometry allows the application of a bias voltage. This applied bias voltage results in a reduction of the required switched voltage and a linearization of the response curve. When this advanced actuator is coupled with non-linear springs, the response curve becomes even more linear. The response curve of the springs is tailored to produce an actuator with extremely linear displacement vs. voltage characteristics.

  10. Development of a Test for Evaluation of the Hydrothermal Stability of Sorbents Used in Closed-Loop CO2 Removal Systems

    NASA Technical Reports Server (NTRS)

    Knox, James C.; Gauto, Hernando; Miller, Lee A.

    2015-01-01

    The International Space Station Carbon Dioxide Removal Assembly uses zeolite 5A molecular sieve material packed into beds for the capture of cabin CO2. The beds are cyclically heated to drive off the CO2 and restore the removal capacity. Over time, the sorbent material has been found to break down resulting in dust that restricts flow through the beds. Humidity adsorbed in the 5A zeolite when it is heated is a suspected cause of this sorbent degradation. To evaluate the impact of adsorbed water during thermal cycling, the Hydrothermal Stability Test was developed. The test configuration provides comparative side-by-side flow restriction data for two sorbent materials at specifically controlled humidity levels. While the initial focus of the testing is on 5A zeolite materials currently used on the ISS, the system will also be used to evaluate future candidate materials. This paper describes the approach, the test system, current results, and future testing.

  11. Evaluation of the geologic relations and seismotectonic stability of the Yucca Mountain area Nevada Nuclear Waste site investigation (NNWSI). Progress report, October 1, 1992--September 30, 1993

    SciTech Connect

    1993-09-30

    This report provides a summary of progress for the project {open_quotes}Evaluation of the Geologic Relations and Seismotectonic Stability of the Yucca Mountain Area, Nevada Nuclear Waste Site Investigation (NNWSI).{close_quotes} A similar report was previously provided for the period of 1 October 1991 to 30 September 1992. The report initially covers the activities of the General Task and is followed by sections that describe the progress of the other ongoing Tasks. This report summarizes the geologic and seismotectonic studies conducted at Yucca Mountain during the contract period including Quaternary tectonics, an evaluation of mineral resource potential of the area, caldera geology, and volcano-tectonic activity at and near the site. A report of basinal studies conducted during the contract period is also included. Selected papers are indexed separately for inclusion in the Energy Science and Technology Database.

  12. Characteristics of pulsed power generator by versatile inductive voltage adder

    NASA Astrophysics Data System (ADS)

    Yatsui, Kiyoshi; Shimiya, Kouichi; Masugata, Katsumi; Shigeta, Masao; Shibata, Kazuhiko

    2005-10-01

    A pulsed power generator by inductive voltage adder, versatile inductive voltage adder (VIVA-I), which features a high average potential gradient (2.5 MV/m), was designed and is currently in operation,. It was designed to produce an output pulse of 4 MV/60 ns by adding 2 MV pulses in two-stages of induction cells, where amorphous cores are installed. As a pulse forming line, we used a Blumlein line with the switching reversed, where cores are automatically biased due to the presence of prepulse. Good reproducibility was obtained even in the absence of the reset pulse. Within [similar]40% of full charge voltage, pulsed power characteristics of Marx generator, pulse forming line (PFL), transmission line (TL), and induction cells were tested for three types of loads; open-circuit, dummy load of liquid (CuSO4) resistor, and electron beam diode. In the open-circuit test, [similar]2.0 MV of output voltage was obtained with good reproducibility. Dependences of output voltage on diode impedances were evaluated by using various dummy loads, and the results were found as expected. An electron-beam diode was operated successfully, and [similar]18 kA of beam current was obtained at the diode voltage of [similar]1 MV.

  13. 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.

  14. Molecular determinants of coupling between the domain III voltage-sensor and pore of a sodium channel

    PubMed Central

    Muroi, Yukiko; Arcisio-Miranda, Manoel; Chowdhury, Sandipan; Chanda, Baron

    2010-01-01

    In a voltage-dependent sodium channel, the activation of voltage-sensors upon depolarization leads to the opening of pore gates. To elucidate the principles underlying this conformational coupling, we investigated a putative gating interface in domain III of the sodium channel using voltage-clamp fluorimetry and tryptophan-scanning mutagenesis. Most mutations have similar energetic effects on voltage-sensor activation and pore opening. However, several mutations stabilized the activated voltage-sensor while concurrently destabilizing the open pore. Mapping of these mutations onto a homology model of the sodium channel showed that most localize to hinge regions of the gating interface. Our analysis shows that these residues are involved in energetic coupling of the voltage-sensor and the pore when both are in the resting or activated conformations, supporting the notion that electromechanical coupling in a voltage-dependent ion channel involves the movement of rigid segments connected by elastic hinges. PMID:20118934

  15. Development of a New Voltage Sag Compensator with a Gradationally Controlled Voltage Inverter

    NASA Astrophysics Data System (ADS)

    Yamada, Masaki; Iwata, Akihiko; Hatakeyama, Yoshihiro; Ishii, Yasuhiro

    A new voltage sag compensator with a gradationally controlled voltage inverter which exceeds SEMI F47 standard has been developed. It consists of a gradationally controlled voltage inverter in which inverters are connected in series and are charged at different voltages to each other, and which outputs the sum of each output voltage. This system is small and with an extremely low loss.

  16. Stability of Biases in Self-Evaluation and Relations to Well-Being among Elementary School Children

    ERIC Educational Resources Information Center

    Bouffard, Therese; Vezeau, Carole; Roy, Mathieu; Lengele, Aurelie

    2011-01-01

    This paper aims to investigate to what extent a bias in self-evaluation is an enduring characteristic among children, and whether there is a relationship between the trajectory of children's self-evaluation bias over a five-year period and their psychosocial adjustment. 462 children (200 boys) in Grade 3 (mean age=8.6 years old) or Grade 4 (mean…

  17. Through thick and thin: tuning the threshold voltage in organic field-effect transistors.

    PubMed

    Martínez Hardigree, Josué F; Katz, Howard E

    2014-04-15

    Organic semiconductors (OSCs) constitute a class of organic materials containing densely packed, overlapping conjugated molecular moieties that enable charge carrier transport. Their unique optical, electrical, and magnetic properties have been investigated for use in next-generation electronic devices, from roll-up displays and radiofrequency identification (RFID) to biological sensors. The organic field-effect transistor (OFET) is the key active element for many of these applications, but the high values, poor definition, and long-term instability of the threshold voltage (V(T)) in OFETs remain barriers to realization of their full potential because the power and control circuitry necessary to compensate for overvoltages and drifting set points decrease OFET practicality. The drifting phenomenon has been widely observed and generally termed "bias stress." Research on the mechanisms responsible for this poor V(T) control has revealed a strong dependence on the physical order and chemical makeup of the interfaces between OSCs and adjacent materials in the OFET architecture. In this Account, we review the state of the art for tuning OFET performance via chemical designs and physical processes that manipulate V(T). This parameter gets to the heart of OFET operation, as it determines the voltage regimes where OFETs are either ON or OFF, the basis for the logical function of the devices. One obvious way to decrease the magnitude and variability of V(T) is to work with thinner and higher permittivity gate dielectrics. From the perspective of interfacial engineering, we evaluate various methods that we and others have developed, from electrostatic poling of gate dielectrics to molecular design of substituted alkyl chains. Corona charging of dielectric surfaces, a method for charging the surface of an insulating material using a constant high-voltage field, is a brute force means of shifting the effective gate voltage applied to a gate dielectric. A gentler and more direct method is to apply surface voltage to dielectric interfaces by direct contact or postprocess biasing; these methods could also be adapted for high throughput printing sequences. Dielectric hydrophobicity is an important chemical property determining the stability of the surface charges. Functional organic monolayers applied to dielectrics, using the surface attachment chemistry made available from "self-assembled" monolayer chemistry, provide local electric fields without any biasing process at all. To the extent that the monolayer molecules can be printed, these are also suitable for high throughput processes. Finally, we briefly consider V(T) control in the context of device integration and reliability, such as the role of contact resistance in affecting this parameter. PMID:24684566

  18. Stability evaluation of reference genes for real-time PCR in zebrafish (Danio rerio) exposed to cadmium chloride and subsequently infected by bacteria Aeromonas hydrophila.

    PubMed

    Lang, Xingping; Wang, Lan; Zhang, Zuobing

    2016-01-01

    Environmental and occupational cadmium (Cd) toxicity is a global concern, and the model organism zebrafish is an ideal species to investigate Cd toxicity. Among various detecting techniques, quantitative real-time PCR (qPCR) is a sensitive and efficient tool. Stable reference genes are critical for relative qPCR analysis. However, accumulated evidence shows that conventional reference genes can vary significantly under different experimental setups. Here we evaluated the stability of eight candidate reference genes of zebrafish with or without exposure to different concentrations of Cd. The results showed that the best four suitable reference genes in the five selected organs were: (1) spleen: ?-actin>gapdh>ef1?>rpl13?; (2) kidney: rplp2>rpl7>?-actin>ef1?; (3) liver: rpl7>rpl13?>?-actin>ef1?; (4) gills: rplp2>gapdh>rnf7>ef1?; (5) intestine: ef1?>rnf7>rplp2>rpl13?. Moreover, we further assessed the expression stability of the four reference genes for Cd immunotoxicology studies in zebrafish. The expression profiles showed that ef1? in spleen and kidney, rpl13a in liver and rplp2 in intestine were the most suitable reference genes at 12h and 9 days after the injection with Aeromonas hydrophila following Cd exposure. In gills, the expression of gapdh was more stable than ef1? after 9 days of bacteria challenge while ef1? showed a higher stability than gapdh at 12h after bacteria injection. In conclusion, this study has demonstrated that different tissues of zebrafish have different suitable reference genes after Cd exposure and the subsequently pathogenic insults for qPCR. It emphasized the importance of reference gene evaluation for studies using qPCR, in particular when investigations involve factors not explored previously. PMID:26675370

  19. 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

  20. Ultrasonic emulsification of parenteral valproic acid-loaded nanoemulsion with response surface methodology and evaluation of its stability.

    PubMed

    Tan, Suk Fei; Masoumi, Hamid Reza Fard; Karjiban, Roghayeh Abedi; Stanslas, Johnson; Kirby, Brian P; Basri, Mahiran; Basri, Hamidon Bin

    2016-03-01

    Response surface methodology (RSM) was used to optimize the formulation of a nanoemulsion for central delivery following parenteral administration. A mixture of medium-chain triglyceride (MCT) and safflower seed oil (SSO) was determined as a sole phase from the emulsification properties. Similarly, a natural surfactant (lecithin) and non-ionic surfactant (Tween 80) (ratio 1:2) were used in the formulation. A central composite design (CCD) with three-factor at five-levels was used to optimize the processing method of high energy ultrasonicator. Effects of pre-sonication ultrasonic intensity (A), sonication time (B), and temperature (C) were studied on the preparation of nanoemulsion loaded with valproic acid. Influence of the aforementioned specifically the effects of the ultrasonic processing parameters on droplet size and polydispersity index were investigated. From the analysis, it was found that the interaction between ultrasonic intensity and sonication time was the most influential factor on the droplet size of nanoemulsion formulated. Ultrasonic intensity (A) significantly affects the polydispersity index value. With this optimization method, a favorable droplet size of a nanoemulsion with reasonable polydispersity index was able to be formulated within a short sonication time. A valproic acid loaded nanoemulsion can be obtained with 60% power intensity for 15min at 60°C. Droplet size of 43.21±0.11nm with polydispersity index of 0.211 were produced. The drug content was then increased to 1.5%. Stability study of nanoemulsion containing 1.5% of valproic acid had a good stability as there are no significant changes in physicochemical aspects such as droplet size and polydispersity index. With the characteristisation study of pH, viscosity, transmission electron microscope (TEM) and stability assessment study the formulated nanoemulsion has the potential to penetrate blood-brain barrier in the treatment of epilepsy. PMID:26585010

  1. Effects of Electrode Material on the Voltage of a Tree-Based Energy Generator.

    PubMed

    Hao, Zhibin; Wang, Guozhu; Li, Wenbin; Zhang, Junguo; Kan, Jiangming

    2015-01-01

    The voltage between a standing tree and its surrounding soil is regarded as an innovative renewable energy source. This source is expected to provide a new power generation system for the low-power electrical equipment used in forestry. However, the voltage is weak, which has caused great difficulty in application. Consequently, the development of a method to increase the voltage is a key issue that must be addressed in this area of applied research. As the front-end component for energy harvesting, a metal electrode has a material effect on the level and stability of the voltage obtained. This study aimed to preliminarily ascertain the rules and mechanisms that underlie the effects of electrode material on voltage. Electrodes of different materials were used to measure the tree-source voltage, and the data were employed in a comparative analysis. The results indicate that the conductivity of the metal electrode significantly affects the contact resistance of the electrode-soil and electrode-trunk contact surfaces, thereby influencing the voltage level. The metal reactivity of the electrode has no significant effect on the voltage. However, passivation of the electrode materials markedly reduces the voltage. Suitable electrode materials are demonstrated and recommended. PMID:26302491

  2. Effects of Electrode Material on the Voltage of a Tree-Based Energy Generator

    PubMed Central

    2015-01-01

    The voltage between a standing tree and its surrounding soil is regarded as an innovative renewable energy source. This source is expected to provide a new power generation system for the low-power electrical equipment used in forestry. However, the voltage is weak, which has caused great difficulty in application. Consequently, the development of a method to increase the voltage is a key issue that must be addressed in this area of applied research. As the front-end component for energy harvesting, a metal electrode has a material effect on the level and stability of the voltage obtained. This study aimed to preliminarily ascertain the rules and mechanisms that underlie the effects of electrode material on voltage. Electrodes of different materials were used to measure the tree-source voltage, and the data were employed in a comparative analysis. The results indicate that the conductivity of the metal electrode significantly affects the contact resistance of the electrode-soil and electrode-trunk contact surfaces, thereby influencing the voltage level. The metal reactivity of the electrode has no significant effect on the voltage. However, passivation of the electrode materials markedly reduces the voltage. Suitable electrode materials are demonstrated and recommended. PMID:26302491

  3. Stability, boundedness, and lagrange stability of fractional differential equations with initial time difference.

    PubMed

    Çiçek, Muhammed; Yakar, Co?kun; O?ur, Bülent

    2014-01-01

    Differential inequalities, comparison results, and sufficient conditions on initial time difference stability, boundedness, and Lagrange stability for fractional differential systems have been evaluated. PMID:24693255

  4. High Voltage Space Solar Arrays

    NASA Technical Reports Server (NTRS)

    Ferguson, D. C.; Hillard, G. B.; Vayner, B. V.; Galofaro, J. T.; Lyons, Valerie (Technical Monitor)

    2002-01-01

    Recent tests performed at the NASA Glenn Research Center and elsewhere have shown promise in the design and construction of high voltage (300-1000 V) solar arrays for space applications. Preliminary results and implications for solar array design will be discussed, with application to direct-drive electric propulsion and space solar power.

  5. 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.

  6. 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.

  7. ABBGroup-1-High voltage lab

    E-print Network

    Basse, Nils Plesner

    is designed to protect an electrical circuit from damage caused by overload or short-circuit. A circuit in all power systems. They are the final link in protection of the power system from short-circuits. GENERATION System voltage: 12-24 kV Rated current: 6000-24000 A Max. short-circuit current: 50-500 k

  8. ABBGroup-1-High voltage lab

    E-print Network

    Basse, Nils Plesner

    . It is designed to protect an electrical circuit from damage caused by overload or short-circuit. A circuit components in all power systems. They are the final link in protection of the power system from short-circuits. GENERATION System voltage: 12-24 kV Rated current: 6000-24000 A Max. short-circuit current: 50-500 k

  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 Fluctuation Compensator for Shinkansen

    NASA Astrophysics Data System (ADS)

    Uzuka, Tetsuo; Ikedo, Shouji; Ueda, Keiji; Mochinaga, Yoshifumi; Funahashi, Sadao; Ide, Koiti

    In AC electric Railway, three-phase voltage is changed into the single-phase circuit of two circuits with the Scott-connected transformer. If it becomes large unbalancing of the load between single-phase circuits, voltage fluctuation becomes large on three-phase side. Then, Railway Static Power Conditioner (RPC) was developed for the purpose of controlling voltage fluctuation on three-phase side. An RPC is comprised of a pair of self-commutated PWM inverters. These inverters connect the main phase and teaser feeding buses, coupled with a DC side capacitor such as a Back-To-Back (BTB) converter. In this way, the two self-commutated inverters can act as a static var compensator (SVC) to compensate for the reactive power and as an active power accommodator from one feeding bus to another. 20MVA/60kV RPCs started commercial operation in 2002 at each two substations on the newly extended Tohoku Shinkansen for compensating voltage fluctuation on three-phase side caused by traction loads, absorbing harmonic current. The results of operational testing indicate that an RPC can accommodate single-phase loads such as those of PWM-controlled Shinkansen and thyristor phase-controlled Shinkansen, and handle the exciting rush current of transformers, as well as compensate for harmonics successfully.

  11. Saving Megawatts with Voltage Optimization 

    E-print Network

    Wilson, T.; Bell, D.

    2010-01-01

    In September 2008, PCS UtiliData commissioned an Industrial Voltage Optimization system at the Plum Creek Timber Medium Density Fiberboard facility in Columbia Falls, Montana. The system was based upon the AdaptiVolt(TM) Volt/VAR Optimization system...

  12. 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

  13. Voltage stress effects on microcircuit accelerated life test failure rates

    NASA Technical Reports Server (NTRS)

    Johnson, G. M.

    1976-01-01

    The applicability of Arrhenius and Eyring reaction rate models for describing microcircuit aging characteristics as a function of junction temperature and applied voltage was evaluated. The results of a matrix of accelerated life tests with a single metal oxide semiconductor microcircuit operated at six different combinations of temperature and voltage were used to evaluate the models. A total of 450 devices from two different lots were tested at ambient temperatures between 200 C and 250 C and applied voltages between 5 Vdc and 15 Vdc. A statistical analysis of the surface related failure data resulted in bimodal failure distributions comprising two lognormal distributions; a 'freak' distribution observed early in time, and a 'main' distribution observed later in time. The Arrhenius model was shown to provide a good description of device aging as a function of temperature at a fixed voltage. The Eyring model also appeared to provide a reasonable description of main distribution device aging as a function of temperature and voltage. Circuit diagrams are shown.

  14. Analysis and test evaluation of the dynamic stability of three advanced turboprop models at zero forward speed

    NASA Technical Reports Server (NTRS)

    Smith, Arthur F.

    1985-01-01

    Results of static stability wind tunnel tests of three 62.2 cm (24.5 in) diameter models of the Prop-Fan are presented. Measurements of blade stresses were made with the Prop-Fans mounted on an isolated nacelle in an open 5.5 m (18 ft) wind tunnel test section with no tunnel flow. The tests were conducted in the United Technology Research Center Large Subsonic Wind Tunnel. Stall flutter was determined by regions of high stress, which were compared with predictions of boundaries of zero total viscous damping. The structural analysis used beam methods for the model with straight blades and finite element methods for the models with swept blades. Increasing blade sweep tends to suppress stall flutter. Comparisons with similar test data acquired at NASA/Lewis are good. Correlations between measured and predicted critical speeds for all the models are good. The trend of increased stability with increased blade sweep is well predicted. Calculated flutter boundaries generaly coincide with tested boundaries. Stall flutter is predicted to occur in the third (torsion) mode. The straight blade test shows third mode response, while the swept blades respond in other modes.

  15. An Experimental Evaluation of Generalized Predictive Control for Tiltrotor Aeroelastic Stability Augmentation in Airplane Mode of Flight

    NASA Technical Reports Server (NTRS)

    Kvaternik, Raymond G.; Piatak, David J.; Nixon, Mark W.; Langston, Chester W.; Singleton, Jeffrey D.; Bennett, Richard L.; Brown, Ross K.

    2001-01-01

    The results of a joint NASA/Army/Bell Helicopter Textron wind-tunnel test to assess the potential of Generalized Predictive Control (GPC) for actively controlling the swashplate of tiltrotor aircraft to enhance aeroelastic stability in the airplane mode of flight are presented. GPC is an adaptive time-domain predictive control method that uses a linear difference equation to describe the input-output relationship of the system and to design the controller. The test was conducted in the Langley Transonic Dynamics Tunnel using an unpowered 1/5-scale semispan aeroelastic model of the V-22 that was modified to incorporate a GPC-based multi-input multi-output control algorithm to individually control each of the three swashplate actuators. Wing responses were used for feedback. The GPC-based control system was highly effective in increasing the stability of the critical wing mode for all of the conditions tested, without measurable degradation of the damping in the other modes. The algorithm was also robust with respect to its performance in adjusting to rapid changes in both the rotor speed and the tunnel airspeed.

  16. RAPD and ISSR based evaluation of genetic stability of micropropagated plantlets of Morus alba L. variety S-1.

    PubMed

    Saha, Soumen; Adhikari, Sinchan; Dey, Tulsi; Ghosh, Parthadeb

    2016-02-01

    Plant regeneration through rapid in vitro clonal propagation of nodal explants of Morus alba L. variety S-1 was established along with genetic stability analysis of regenerates. Axillary shoot bud proliferation was achieved on Murashige and Skoog (MS) medium in various culture regimes. Highest number of shoots (5.62 ± 0.01), with average length 4.19 ± 0.01 cm, was initially achieved with medium containing 0.5 mg/l N(6)-benzyladenine (BA) and 3% sucrose. Repeated subculturing of newly formed nodal parts after each harvest up to sixth passage, yielded highest number of shoots (about 32.27) per explants was obtained after fourth passage. Rooting of shoots occurred on 1/2 MS medium supplemented with 1.0 mg/1 Indole-3-butyric acid (IBA). About 90% (89.16) of the plantlets transferred to the mixture of sand:soil:organic manure (2:2:1) in small plastic pots acclimatized successfully. Genetic stability of the discussed protocol was confirmed by two DNA-based fingerprinting techniques i.e. RAPD (random amplified polymorphic DNA) and ISSR (inter-simple sequence repeat). This protocol can be used for commercial propagation and for future genetic improvement studies. PMID:26693403

  17. RAPD and ISSR based evaluation of genetic stability of micropropagated plantlets of Morus alba L. variety S-1

    PubMed Central

    Saha, Soumen; Adhikari, Sinchan; Dey, Tulsi; Ghosh, Parthadeb

    2015-01-01

    Plant regeneration through rapid in vitro clonal propagation of nodal explants of Morus alba L. variety S-1 was established along with genetic stability analysis of regenerates. Axillary shoot bud proliferation was achieved on Murashige and Skoog (MS) medium in various culture regimes. Highest number of shoots (5.62 ± 0.01), with average length 4.19 ± 0.01 cm, was initially achieved with medium containing 0.5 mg/l N6-benzyladenine (BA) and 3% sucrose. Repeated subculturing of newly formed nodal parts after each harvest up to sixth passage, yielded highest number of shoots (about 32.27) per explants was obtained after fourth passage. Rooting of shoots occurred on 1/2 MS medium supplemented with 1.0 mg/1 Indole-3-butyric acid (IBA). About 90% (89.16) of the plantlets transferred to the mixture of sand:soil:organic manure (2:2:1) in small plastic pots acclimatized successfully. Genetic stability of the discussed protocol was confirmed by two DNA-based fingerprinting techniques i.e. RAPD (random amplified polymorphic DNA) and ISSR (inter-simple sequence repeat). This protocol can be used for commercial propagation and for future genetic improvement studies. PMID:26693403

  18. Polyphenol profiling of a red-fleshed apple cultivar and evaluation of the color extractability and stability in the juice.

    PubMed

    Malec, Marta; Le Quéré, Jean-Michel; Sotin, Hélène; Kolodziejczyk, Krzysztof; Bauduin, Rémi; Guyot, Sylvain

    2014-07-23

    Red-fleshed apples can be used for the production of innovative products such as rosé juices and ciders. Phenolic compounds including procyanidins (i.e., condensed tannins) and anthocyanins were quantified in the fruits and juices of a red-fleshed apple cultivar by chromatography coupled to UV-visible and mass spectrometry. Juice color was characterized by colorimetry. The influence of oxygen, pH, sulfites, ascorbic acid, and copper on the color stability of the juice was studied in an experimental design. Fruits were rich in polyphenols (0.5 g/100 g FW), with anthocyanins and procyanidins accounting for 9 and 73% of total polyphenols, respectively. Extractability of anthocyanins in the juice was 26%. Juice storage under air atmosphere at 35 °C resulted in significant browning with the anthocyanin level decreasing up to 86% after 14 days. In contrast, color was stable for storage under argon atmosphere. Sulfites, ascorbic acid, and copper have only a slightly influence on color stability in those conditions. PMID:24655330

  19. The limitation of the toxicity characteristic leaching procedure for evaluating cement-based stabilized/solidified waste forms

    SciTech Connect

    Poon, C.S.; Lio, K.W.

    1997-12-31

    The US Environmental Protection Agency`s Toxicity Characteristic Leaching Procedure (TCLP) is commonly used as a regulatory tool to determine whether or not a waste can be classified as a hazardous waste. The validity of the test procedure for assessing cement-based stabilized/solidified heavy metal wastes is examined in this paper. Synthetic cement-based heavy metal waste forms with different ANC were prepared and subjected to TCLP to study the effect of waste acid neutralizing capacity (ANC) on metal leaching. A real waste was also obtained from a local commercial treatment facility and tested to verify the findings. The results showed that as long as the stabilized/solidified waste forms have sufficient ANC to neutralize the acidity of the leachant, the leaching of metals will be small and the performance of the different waste forms cannot be differentiated. The test therefore has limited use in comparing the performance of different cement-based waste forms. A modified test procedure is proposed.

  20. High voltage battery cell scanner development

    NASA Technical Reports Server (NTRS)

    Lepisto, J. W.; Decker, D. K.; Graves, J.

    1983-01-01

    Battery cell voltage scanners have been previously used in low voltage spacecraft applications. In connection with future missions involving an employment of high-power high voltage power subsystems and/or autonomous power subsystem management for unattended operation, it will be necessary to utilize battery cell voltage scanners to provide battery cell voltage information for early detection of impending battery cell degradation/failures. In preparation for such missions, a novel battery cell voltage scanner design has been developed. The novel design makes use of low voltage circuit modules which can be applied to high voltage batteries in a building block fashion. A description is presented of the design concept and test results of the high voltage battery cell scanner, and its operation with an autonomously managed power subsystem is discussed.

  1. Voltage-gated proton channels.

    PubMed

    Decoursey, Thomas E

    2012-04-01

    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 approximately 10(3) times smaller than most ion channels, voltage-dependent gating that is strongly modulated by the pH gradient, ?pH, and potent inhibition by Zn(2+) (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

  2. A new VME-based high voltage power supply for large photomultiplier systems

    NASA Astrophysics Data System (ADS)

    Neumaier, S.; Gutbrod, H. H.; Hubbeling, T.; Kolb, B. W.; Purschke, M. L.; Ippolitov, M.; Manko, V.; Mgebrishvili, G.; Nijanin, A.; Sibiryak, Y.; Tsvetkov, A.; Vinogradov, A.; Barlag, C.; Blume, C.; Bohne, E.-M.; Bucher, D.; Claussen, A.; Peitzmann, T.; Schepers, G.; Schlagheck, H.

    1995-02-01

    We describe a new high voltage power supply, developed for the leadglass calorimeter of the WA98 experiment at CERN. The high voltage is produced for each of the 10 080 photomultiplier tubes of the detector individually, by the same number of active bases with on-board Greinacher voltage multipliers. The full VME-based HV controller system, which addresses each base via bus cables once per second, is miniaturized and fits into a single VME crate. The main advantages of this approach are the low heat dissipation, the considerably reduced amount of cabling and cost, as well as the high stability and low noise of the system.

  3. Design and power management of an offshore medium voltage DC microgrid realized through high voltage power electronics technologies and control

    NASA Astrophysics Data System (ADS)

    Grainger, Brandon Michael

    The growth in the electric power industry's portfolio of Direct Current (DC) based generation and loads have captured the attention of many leading research institutions. Opportunities for using DC based systems have been explored in electric ship design and have been a proven, reliable solution for transmitting bulk power onshore and offshore. To integrate many of the renewable resources into our existing AC grid, a number of power conversions through power electronics are required to condition the equipment for direct connection. Within the power conversion stages, there is always a requirement to convert to or from DC. The AC microgrid is a conceptual solution proposed for integrating various types of renewable generation resources. The fundamental microgrid requirements include the capability of operating in islanding mode and/or grid connected modes. The technical challenges associated with microgrids include (1) operation modes and transitions that comply with IEEE1547 without extensive custom engineering and (2) control architecture and communication. The Medium Voltage DC (MVDC) architecture, explored by the University of Pittsburgh, can be visualized as a special type of DC microgrid. This dissertation is multi-faceted, focused on many design aspects of an offshore DC microgrid. The focal points of the discussion are focused on optimized high power, high frequency magnetic material performance in electric machines, transformers, and DC/DC power converters---all components found within offshore, power system architectures. A new controller design based upon model reference control is proposed and shown to stabilize the electric motor drives (modeled as constant power loads), which serve as the largest power consuming entities in the microgrid. The design and simulation of a state-of-the-art multilevel converter for High Voltage DC (HVDC) is discussed and a component sensitivity analysis on fault current peaks is explored. A power management routine is proposed and evaluated as the DC microgrid is disturbed through various mode transitions. Finally, two communication protocols are described for the microgrid---one to minimize communication overhead inside the microgrid and another to provide robust and scalable intra-grid communication. The work presented is supported by Asea Brown Boveri (ABB) Corporate Research Center within the Active Grid Infrastructure program, the Advanced Research Project Agency - Energy (ARPA-E) through the Solar ADEPT program, and Mitsubishi Electric Corporation (MELCO).

  4. Analysis and test evaluation of the dynamic response and stability of three advanced turboprop models at low forward speed

    NASA Technical Reports Server (NTRS)

    Smith, Arthur F.

    1985-01-01

    Results of wind tunnel tests at low forward speed for blade dynamic response and stability 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. Low speed stall flutter tests were conducted at Mach numbers from 0.0 to 0.35. Measurements are compared to Eigen-solution flutter boundaries. Calculated 1P stress response agrees favorably with experiment. Predicted stall flutter boundaries correlate well with measured high stress regions. Stall flutter is significantly reduced by increased blade sweep. Susceptibility to stall flutter decreases rapidly with forward speed.

  5. 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

  6. Integral Impact of BTI and Voltage Temperature Variation on SRAM Sense Amplifier

    E-print Network

    Integral Impact of BTI and Voltage Temperature Variation on SRAM Sense Amplifier Innocent Agbo amplifiers, etc. This paper characterizes the combined impact of BTI and voltage temperature fluctuations on the memory sense amplifier for different technology nodes (45nm up to 16nm). The evaluation metric

  7. An Experimental Study on Voltage Compensation Method using Autonomous Decentralized Control of Distributed Generators

    NASA Astrophysics Data System (ADS)

    Tanaka, Shunsuke; Suzuki, Hirokazu

    When many distributed generators (DGs) are connected to a distribution line, the upward power flow from DGs causes the difficulty in line voltage regulation. As the countermeasure, we propose several methods to control the line voltage by use of DGs' reactive power outputs. These methods using only DGs' reactive power are implemented in an autonomous decentralized way. DGs with the function to estimate the line impedance provide the power system with reactive power according to the estimated impedance value, and regulate the line voltage. We evaluate the effect of the proposed methods for voltage compensation by experimental studies using commercial grid-connected inverters for PV system.

  8. 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.

  9. Low Beam Voltage, 10 MW, L-Band Cluster Klystron

    SciTech Connect

    Teryaev, V.; Yakovlev, V.P.; Kazakov, S.; 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.

  10. Arc voltage measurements of the hyperbaric MIG process

    SciTech Connect

    Huismann, G.; Hoffmeister, H.

    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.

  11. [Dynamics of ECG voltage in changing gravity].

    PubMed

    Saltykova, M M; At'kov, O Iu; Capderou, A; Morgun, V V; Gusakov, V A; Khe?mets, G I; Konovalov, G A; Kondratiuk, L L; Kataev, Iu V; Voronin, L I; Kaspranski?, R R; Vaida, P

    2006-01-01

    Comparative analysis of the QRS voltage response to gravity variations was made using the data about 26 normal human subjects collected in parabolic flights (CNERS-AIRBUS A300 Zero-G, n=23; IL-76MD, n=3) and during the tilt test (head-up tilt at 70 degrees for a min and head-down tilt at-15 degrees for 5 min, n=14). Both the parabolic flights and provocative tilt tests affected R-amplitude in the Z lead. During the hypergravity episodes it was observed in 95% of cases with the mean gain of 16% and maximal--56%. On transition to the horizontal position, the Rz-amplitude showed a rise in each subject (16% on the average). In microgravity, the Rz-amplitude reduced in 95% of the observations. The voltage decline averaged 18% and reached 49% at the maximum. The head-down tilt was conducive to Rz reduction in 78% of observations averaging 2%. Analysis of the ECG records under changing gravity when blood redistribution developed within few seconds not enough for serious metabolic shifts still revealed QRS deviations associated exclusively with the physical factors, i.e., alteration in tissue conduction and distance to electrodes. Our findings can stand in good stead in evaluation of the dynamics of predictive ECG parameters during long-term experiments leading to changes as in tissue conduction, so metabolism. PMID:16915811

  12. Flight-Test Evaluation of the Longitudinal Stability and Control Characteristics of 0.5-Scale Models of the Fairchild Lark Pilotless-Aircraft Configuration. Static Longitudinal Stability of Models with Wing Flap Deflections of 0 Deg and 15 Deg, TED No. NACA 2387

    NASA Technical Reports Server (NTRS)

    Stone, David G.

    1947-01-01

    From flight tests of 0.5-scale models of the Fairchild Lark pilotless aircraft conducted at the flight test station of the Pilotless Aircraft Research Division at Wallops Island, Va., some evaluations of the static longitudinal stability were obtained by analysis of the short-period oscillations induced by the abrupt movement of the rudder elevators. The analysis shows that for the Lark configuration with wing flap deflections of 0 degrees and 15 degrees the static longitudinal stability decreases slightly up to the critical Mach number and than as the Mach number increases further the stability increases greatly.

  13. New internal multi-range resistors for ac voltage calibration by using TVC

    NASA Astrophysics Data System (ADS)

    Ali, Rasha S. M.

    2015-10-01

    Accurate calibration of ac voltages up to 1000?V by using thermal converters requires range resistors connected in series with the converter. The combination of a thermal converter and range resistor is known as the thermal voltage converter. In this paper, multi-range internal range resistors are designed and implemented in the National Institute for Standards (NIS), Egypt to cover the ac voltage ranges from 10?V to 750?V. The range resistor values are 2 k?, 10 k?, 20 k?, 40 k?, 100 k?, and 150 k? to cover the voltage ranges 10?V, 50?V, 100?V, 200?V, 500?V, and 750?V, respectively. The six range resistors are mounted in series with a single-junction thermo-element in the same box to provide a new thermal voltage converter. The required range resistor is selected by using a six-pin selector switch. Each resistor is connected to a selector pin. The new thermal voltage converter ranges are automatically calibrated against other standard thermal voltage converters at different frequencies by using a LabVIEW program to determine their ac-dc transfer difference at each range. The expanded uncertainties are estimated according to the GUM for all ranges at different frequencies. The performance of the new thermal voltage converter is also evaluated by comparing its ac-dc differences and its accuracy in measuring the ac voltage at different frequencies with a traditional thermal voltage converter.

  14. [Development of residual voltage testing equipment].

    PubMed

    Zeng, Xiaohui; Wu, Mingjun; Cao, Li; He, Jinyi; Deng, Zhensheng

    2014-07-01

    For the existing measurement methods of residual voltage which can't turn the power off at peak voltage exactly and simultaneously display waveforms, a new residual voltage detection method is put forward in this paper. First, the zero point of the power supply is detected with zero cross detection circuit and is inputted to a single-chip microcomputer in the form of pulse signal. Secend, when the zero point delays to the peak voltage, the single-chip microcomputer sends control signal to power off the relay. At last, the waveform of the residual voltage is displayed on a principal computer or oscilloscope. The experimental results show that the device designed in this paper can turn the power off at peak voltage and is able to accurately display the voltage waveform immediately after power off and the standard deviation of the residual voltage is less than 0.2 V at exactly one second and later. PMID:25330605

  15. Cyclotron Production of High-Specific Activity 55Co and In Vivo Evaluation of the Stability of 55Co Metal-Chelate-Peptide Complexes.

    PubMed

    Mastren, Tara; Marquez, Bernadette V; Sultan, Deborah E; Bollinger, Elizabeth; Eisenbeis, Paul; Voller, Tom; Lapi, Suzanne E

    2015-11-01

    AbstractThis work describes the production of high-specific activity 55Co and the evaluation of the stability of 55Co-metal-chelate-peptide complexes in vivo. 55Co was produced via the 58Ni(p,?)55Co reaction and purified using anion exchange chromatography with an average recovery of 92% and an average specific activity of 1.96 GBq/?mol. 55Co-DO3A and 55Co-NO2A peptide complexes were radiolabeled at 3.7 MBq/?g and injected into HCT-116 tumor xenografted mice. Positron emission tomography (PET) and biodistribution studies were performed at 24 and 48 hours postinjection and compared to those of 55CoCl2. Both 55Co-metal-chelate complexes demonstrated good in vivo stability by reducing the radiotracers' uptake in the liver by sixfold at 24 hours with ~ 1% ID/g and at 48 hours with ~ 0.5% ID/g and reducing uptake in the heart by fourfold at 24 hours with ~ 0.7% ID/g and sevenfold at 48 hours with ~ 0.35% ID/g. These results support the use of 55Co as a promising new radiotracer for PET imaging of cancer and other diseases. PMID:26505224

  16. 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.

  17. Evaluation of various infused cryoprotective ingredients for their freeze-thaw stabilizing and texture improving properties in frozen red hake muscle.

    PubMed

    Bigelow, W; Lee, C M

    2007-01-01

    Various cryoprotective ingredients were evaluated for their freeze-thaw stabilizing and texture improving properties during 6-mo frozen storage when red hake (Urophycis chuss) fillets were injected with sorbitol-sodium tripolyphosphate (STPP) (40% to 60% : 3%), 1.5% alginate, or 0.75% alginate with soy protein isolate (SPI)-sorbitol-STPP (5% to 10% : 40% : 3%). Injection of 10% SPI, 1.5% alginate, or 0.75% alginate-5% SPI effectively improved water binding and retarded the freeze-induced texture changes when drip and cooking loss, centrifugal expressible moisture, protein extractability, SDS-PAGE profile, and Instron and sensory texture were assessed. The sorbitol and STPP combination was not as effective as alginate and SPI. Freeze-susceptible whitefish can be injected with proper cryoprotective ingredients for improved frozen storability. PMID:17995873

  18. 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.

  19. 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

  20. 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.

  1. Evaluation of the geological relationships to gas hydrate formation and stability. Progress report, June 16--September 30, 1988

    SciTech Connect

    Krason, J.; Finley, P.

    1988-12-31

    The summaries of regional basin analyses document that potentially economic accumulations of gas hydrates can be formed in both active and passive margin settings. The principal requirement for gas hydrate formation in either setting is abundant methane. Passive margin sediments with high sedimentation rates and sufficient sedimentary organic carbon can generate large quantities of biogenic methane for hydrate formation. Similarly, active margin locations near a terrigenous sediment source can also have high methane generation potential due to rapid burial of adequate amounts of sedimentary organic matter. Many active margins with evidence of gas hydrate presence correspond to areas subject to upwelling. Upwelling currents can enhance methane generation by increasing primary productivity and thus sedimentary organic carbon. Structural deformation of the marginal sediments at both active and passive sites can enhance gas hydrate formation by providing pathways for migration of both biogenic and thermogenic gas to the shallow gas hydrate stability zone. Additionally, conventional hydrocarbon traps may initially concentrate sufficient amounts of hydrocarbons for subsequent gas hydrate formation.

  2. [Evaluating the Stability of Loop-Mediated Isothermal Amplification Reagents at Irregular Storage Temperatures for On-Site Diagnosis].

    PubMed

    Inoshima, Yasuo; Ishiguro, Naotaka

    2015-11-11

    Temperature-stability of loop-mediated isothermal amplification (LAMP) reagents was determined for their use in on-site diagnosis, such as in farms/pastures. Bst and Csa DNA polymerases and the reagents that were stored at different temperatures (4 or 25°C) for 1, 2, or 4 days were used for the LAMP assay to detect orf virus DNA as a model. After storage at 4 and 25°C for 2 days, the enzymes and reagents were found to retain sufficient activity to carry out successful DNA amplification. Visual diagnosis was also possible with the reagents (Loopamp Fluorescent Detection Reagent or hydroxy naphthol blue, as well as DNA amplification checker, D-Quick) that were stored for 2 days at different temperatures. Although the time taken to obtain the positive/negative results were delayed, the enzymes and reagents, stored at 25°C for 4 days, were active and had the ability to efficiently amplify DNA in less than 50 min. These results indicate that LAMP assay can be successfully utilized for the diagnosis of infectious diseases under non-clinical settings such as for on-site diagnosis in farms/pastures, owing to the fact that the relevant enzymes and reagents does not require restricted temperature storage. PMID:26635003

  3. Evaluation of HLB values of mixed non-ionic surfactants on the stability of oil-in-water emulsion system

    NASA Astrophysics Data System (ADS)

    Nursakinah, I.; Ismail, A. R.; Rahimi, M. Y.; Idris, A. B.

    2013-11-01

    Emulsion oil-in-water was prepared with combination of emulsifiers (non-ionic surfactants) following the HLB (hydrophylic-lipophylic balance) method developed by Griffin. The emulsions were prepared at HLB 10, 11, 12, 13 and 13.6 consisting blend of non-ionic emulsifiers fatty acid ethoxylate with 20 moles bound ethylene oxide and Dehydol LS 1 with 1 mole bound ethylene oxide. A mixture of palm-based methyl ester consisting of C6-10 and C12-18 fatty acid composition was used as palm-based solvent. The physicochemical parameters of the emulsion were characterized by accelerate stability tested at 45°C for two months, measurement of particle size and viscosity test. The result of accelerate test showed that all the emulsion at different HLB were found to be stable in the 2 months observation which assumed to be stable in 1 year of storage. Meanwhile, the particle size measurement data showed that the optimum stable particle size of the emulsion was HLB 12±1. The viscosity test of the emulsion tends to support the data from the particle size and have maximum viscosity 189.89 cP at HLB 12. The obtained results indicate that the optimum stable emulsions can be formulated by a combination of emulsifiers with HLB 12±1 which is compatible with that of required HLB of the oil phase.

  4. Evaluation of the Stability and Performance of a Multi-Stage Riemann Solver in Relativistic Hydrodynamic Simulations

    E-print Network

    J. Sikorski; J. Porter-Sobieraj; D. Kiko?a; M. S?odkowski; P. Aszklar

    2015-10-21

    The work deals with assessing the quality of a multi-stage Riemann solver for relativistic hydrodynamic simulations of heavy-ion collisions. The physical system is described using hydrodynamic conservation laws and then solved numerically. Because of the nature of such hydrodynamic simulations the numerical method has to cope with problems containing both strong discontinuities and smooth solutions, and reproduce these features with a high precision and stability. Moreover, to verify the correctness of the proposed physical model, a massive number of simulations with a high spatial resolution is needed. Due to the high numerical cost, a highly e?cient implementation for solving such large-scale problems is required. The MUSTA-FORCE algorithm is a universal tool for hydrodynamic simulations. It uses simple central schemes and does not require any knowledge of the physical process's details, thus it can be used for virtually any physical system. We investigate the application of the MUSTA-FORCE scheme for relativistic hydrodynamics with GPU computing using single precision ?oating-point operations. We assess the quality of our implementation in terms of simulation accuracy and simulation time.

  5. Comprehensive evaluation of high-steep slope stability and optimal high-steep slope design by 3D physical modeling

    NASA Astrophysics Data System (ADS)

    Lai, Xing-ping; Shan, Peng-fei; Cai, Mei-feng; Ren, Fen-hua; Tan, Wen-hui

    2015-01-01

    High-steep slope stability and its optimal excavation design in Shuichang open pit iron mine were analyzed based on a large 3D physical simulation technique. An optimal excavation scheme with a relatively steeper slope angle was successfully implemented at the northwest wall between Nos. 4 and 5 exploration lines of Shuichang Iron Mine, taking into account the 3D scale effect. The physico-mechanical properties of rock materials were obtained by laboratory tests conducted on sample cores from exploration drilling directly from the iron mine. A porous rock-like composite material was formed for the model, and the mechanical parameters of the material were assessed experimentally; specifically, the effect of water on the sample was quantitatively determined. We adopted an experimental setup using stiff modular applied static loading to carry out a visual excavation of the slope at a random depth. The setup was equipped with acoustic emission (AE) sensors, and the experiments were monitored by crack optical acquirement, ground penetrating radar, and close-field photogrammetry to investigate the mechanisms of rock-mass destabilization in the high-steep slope. For the complex study area, the model results indicated a clear correlation between the model's destabilization resulting from slope excavation and the collected monitoring information. During the model simulation, the overall angle of the slope increased by 1-6 degrees in different sections. Dramatically, the modeled excavation scheme saved over 80 million tons of rock from extraction, generating enormous economic and ecological benefits.

  6. Rapid plasma reagin card test: evaluation of a hand-rotation procedure and stability of the RPR antigen.

    PubMed Central

    Van Dyck, E.; Bogaerts, J.; Piot, P.

    1994-01-01

    Reported are the results of a comparative study of two procedures for the rapid plasma reagin (RPR) test for syphilis serology: in one approach a mechanical rotator was used and in the other, hand rotation was employed. Both procedures were performed on 327 sera. The agreement between both was 98.8%. Three sera that exhibited minimal reactivity (titre = 1) in the mechanical-rotation RPR were nonreactive in the hand-rotation RPR. RPR antigen was stored for 3 months at room temperature (mean, 21 degrees C) and 30 degrees C. There was no difference in the reactivity of 62 sera (50 positive, 12 negative) that were tested using either adversely stored antigens or antigen stored at 4 degrees C. In poorly equipped settings at the primary health care level, the hand-rotation RPR is a practical alternative to mechanical rotation. Also, the stability of the antigen under adverse storage conditions is an additional advantage of RPR for use in tropical areas. PMID:7955023

  7. 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...

  8. SWITCHED-CAPACITOR VOLTAGE CONVERTERS WITH REGULATORS

    E-print Network

    Berns, Hans-Gerd

    LT1054 SWITCHED-CAPACITOR VOLTAGE CONVERTERS WITH REGULATORS SLVS033E ­ FEBRUARY 1990 ­ REVISED-to-Pin Compatible With the LTC1044/7660 description The LT1054 is a bipolar, switched-capacitor voltage converter regulation, a feature not previously available in switched-capacitor voltage converters. By adding

  9. 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

  10. Silver nanoparticles increase cytotoxicity induced by intermediate frequency low voltages.

    PubMed

    Yadegari-Dehkordi, Sajedeh; Sadeghi, Hamid Reza; Attaran-Kakhki, Neda; Shokouhi, Mahin; Sazgarnia, Ameneh

    2015-12-01

    Electrical properties of the cells play a key role in biological processes. Intermediate frequencies of electrical fields influence the cells proliferation without heat generation and electrical stimulation. Silver nanoparticle (SNP) as a metallic agent can change the electrical characteristics of the cells. We study the effect of low voltages at an intermediate frequency (300 kHz) on a human breast adenocarcinoma cell line (MCF7) in the presence of SNPs. At first, cell toxicity of SNPs was determined at different concentrations. Then three different voltages were applied to the cells for 15?min, both in the presence and absence of SNPs. The treatments efficiency was evaluated by MTT assay. The results showed that the intermediate frequency-low voltages with SNPs not only provide an additive efficacy on cytotoxicity, but also a synergism was observed between these factors. By increasing the voltage from 3 to 9?V, a rising synergistic rate was observed. It seems that the synergistic effect between SNPs and the 300?kHz low voltages can inhibit cell proliferation and/or increases cell death of MCF-7, and hence increases treatment efficiency of SNPs, effectively. PMID:24901460

  11. The screw-helical voltage gating of ion channels.

    PubMed

    Keynes, R D; Elinder, F

    1999-04-22

    In the voltage-gated ion channels of every animal, whether they are selective for K+, Na+ or Ca2+, the voltage sensors are the S4 transmembrane segments carrying four to eight positive charges always separated by two uncharged residues. It is proposed that they move across the membrane in a screw-helical fashion in a series of three or more steps that each transfer a single electronic charge. The unit steps are stabilized by ion pairing between the mobile positive charges and fixed negative charges, of which there are invariably two located near the inner ends of segments S2 and S3 and a third near the outer end of either S2 or S3. Opening of the channel involves three such steps in each domain. PMID:10343407

  12. The screw-helical voltage gating of ion channels.

    PubMed Central

    Keynes, R D; Elinder, F

    1999-01-01

    In the voltage-gated ion channels of every animal, whether they are selective for K+, Na+ or Ca2+, the voltage sensors are the S4 transmembrane segments carrying four to eight positive charges always separated by two uncharged residues. It is proposed that they move across the membrane in a screw-helical fashion in a series of three or more steps that each transfer a single electronic charge. The unit steps are stabilized by ion pairing between the mobile positive charges and fixed negative charges, of which there are invariably two located near the inner ends of segments S2 and S3 and a third near the outer end of either S2 or S3. Opening of the channel involves three such steps in each domain. PMID:10343407

  13. 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

    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.

  14. A Regional-Scale Evaluation on Environmental Stability Conditions for Convective Rain under Climate Change from Super-High-Resolution GCM Simulations

    NASA Astrophysics Data System (ADS)

    Takemi, T.; Nomura, S.; Oku, Y.; Ishikawa, H.

    2011-12-01

    Understanding and forecasting of convective rain due to intense thunderstorms, which develop under conditions both with and without significant synoptic-scale and/or mesoscale forcings, are critical in dealing with disaster prevention/mitigation and developing urban planning appropriate for disaster management. Thunderstorms rapidly develop even during the daytimes of fair weather conditions without any external forcings, and sometimes become strong enough to induce local-scale meteorological disasters such as torrential rain, flush flooding, high winds, and tornadoes/gusts. With the growing interests in climate change, future changes in the behavior of such convectively generated extreme events have gained scientific and societal interests. This study conducted the regional-scale evaluations on the environmental stability conditions for convective rain that develops under synoptically undisturbed, summertime conditions by using the outputs of super-high-resolution AGCM simulations, at a 20-km resolution, for the present, the near-future, and the future climates under global warming with IPCC A1B emission scenario. The GCM, MRI-AGCM3.2S, was developed by Meteorological Research Institute of Japan Meteorological Agency under the KAKUSHIN program funded by the Ministry of Education, Culture, Sports, Science, and Technology of Japan. The climate simulation outputs that were used in this study corresponded to three 25-year periods: 1980-2004 for the present climate; 2020-2044 for the near-future climate; and 2075-2099 for the future climate. The Kanto Plain that includes the Tokyo metropolitan area was chosen as the study area, since the Tokyo metropolitan area is one of the largest metropolises in the world and is vulnerable to extreme weather events. Therefore, one of the purposes of this study was to examine how regional-scale evaluations are performed from the super-high-resolution GCM outputs. After verifying the usefulness of the GCM present-climate outputs with observations and operational mesoscale analyses, we examined, as another purpose of this study, the future changes in the environmental stability for convective rain. To diagnose the environmental conditions, some of the commonly used stability parameters and indices were examined. In the future climates, temperature lapse rate decreased in the lower troposphere, while water vapor mixing ratio increased throughout the deep troposphere. The changes in the temperature and moisture profiles resulted in the increase in both precipitable water vapor and convective available potential energy. These projected changes will be enhanced with the future period. Furthermore, the statistical analyses for the differences of the stability parameters between no-rain and rain days under the synoptically undisturbed condition in each simulated climate period indicated that the environmental conditions in terms of the stability parameters that distinguish no-rain and rain events are basically unchanged between the present and the future climates. This result suggests that the environmental characteristics favorable for afternoon rain events in the synoptically undisturbed environments will not change under global warming.

  15. Comparative Evaluation of Bivalent Malaria Rapid Diagnostic Tests versus Traditional Methods in Field with Special Reference to Heat Stability Testing in Central India

    PubMed Central

    Singh, Neeru; Bharti, Praveen K.; Singh, Mrigendra P.; Mishra, Sweta; Shukla, Man M.; Sharma, Ravendra K.; Singh, Rajesh K.

    2013-01-01

    Background Malaria presents a diagnostic challenge in areas where both Plasmodium falciparum and P.vivax are co-endemic. Bivalent Rapid Diagnostic tests (RDTs) showed promise as diagnostic tools for P.falciparum and P.vivax. To assist national malaria control programme in the selection of RDTs, commercially available seven malaria RDTs were evaluated in terms of their performance with special reference to heat stability. Methodology/Principal Findings This study was undertaken in four forested districts of central India (July, 2011– March, 2012). All RDTs were tested simultaneously in field along with microscopy as gold standard. These RDTs were stored in their original packing at 25°C before transport to the field or they were stored at 35°C and 45°C upto 100 days for testing the performance of RDTs at high temperature. In all 2841 patients with fever were screened for malaria of which 26% were positive for P.falciparum, and 17% for P.vivax. The highest sensitivity of any RDT for P.falciparum was 98% (95% CI; 95.9–98.8) and lowest sensitivity was 76% (95% CI; 71.7–79.6). For P.vivax highest and lowest sensitivity for any RDT was 80% (95% CI; 94.9 - 83.9) and 20% (95% CI; 15.6–24.5) respectively. Heat stability experiments showed that most RDTs for P.falciparum showed high sensitivity at 45°C upto 90 days. While for P.vivax only two RDTs maintained good sensitivity upto day 90 when compared with RDTs kept at room temperature. Agreement between observers was excellent for positive and negative readings for both P.falciparum and P.vivax (Kappa >0.6–0.9). Conclusion This is first field evaluation of RDTs regarding their temperature stability. Although RDTs are useful as diagnostic tool for P.falciparum and P.vivax even at high temperature, the quality of RDTs should be regulated and monitored more closely. PMID:23472135

  16. 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.

  17. 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

  18. Evaluating the accotink creek restoration project for improving water quality, in-stream habitat, and bank stability

    USGS Publications Warehouse

    Struck, S.D.; Selvakumar, A.; Hyer, K.; O'Connor, T.

    2007-01-01

    Increased urbanization results in a larger percentage of connected impervious areas and can contribute large quantities of stormwater runoff and significant quantities of debris and pollutants (e.g., litter, oils, microorganisms, sediments, nutrients, organic matter, and heavy metals) to receiving waters. To improve water quality in urban and suburban areas, watershed managers often incorporate best management practices (BMPs) to reduce the quantity of runoff as well as to minimize pollutants and other stressors contained in stormwater runoff. It is well known that land-use practices directly impact urban streams. Stream flows in urbanized watersheds increase in magnitude as a function of impervious area and can result in degradation of the natural stream channel morphology affecting the physical, chemical, and biological integrity of the stream. Stream bank erosion, which also increases with increased stream flows, can lead to bank instability, property loss, infrastructure damage, and increased sediment loading to the stream. Increased sediment loads may lead to water quality degradation downstream and have negative impacts on fish, benthic invertebrates, and other aquatic life. Accotink Creek is in the greater Chesapeake Bay and Potomac watersheds, which have strict sediment criteria. The USEPA (United States Environmental Protection Agency) and USGS (United States Geological Survey) are investigating the effectiveness of stream restoration techniques as a BMP to decrease sediment load and improve bank stability, biological integrity, and in-stream water quality in an impaired urban watershed in Fairfax, Virginia. This multi-year project continuously monitors turbidity, specific conductance, pH, and water temperature, as well as biological and chemical water quality parameters. In addition, physical parameters (e.g., pebble counts, longitudinal and cross sectional stream surveys) were measured to assess geomorphic changes associated with the restoration. Data from the pre-construction and initial post-construction phases are presented in this report. ?? 2007 ASCE.

  19. Evaluation of the effectiveness of sepiolite, bentonite, and phosphate amendments on the stabilization remediation of cadmium-contaminated soils.

    PubMed

    Sun, Yuebing; Sun, Guohong; Xu, Yingming; Liu, Weitao; Liang, Xuefeng; Wang, Lin

    2016-01-15

    A pot trial was conducted to assess the effectiveness of sepiolite, bentonite, and phosphate on the immobilization remediation of cadmium (Cd)-contaminated soils using a set of variables, namely, physiological traits, sequential extraction procedure, plant growth and Cd concentration, and soil enzymatic activities and microbial population. Results showed that superoxide dismutase and peroxidase activities in the leaves of Oryza sativa L. and catalase activities in soils were stimulated after applying the amendments. However, soluble protein contents in leaves and urease and invertase activities in soils were reduced from 7.1% to 31.7%, 1.0%-23.3%, and 21.1%-62.5%, respectively, compared with the control. Results of the sequence extraction procedures revealed that the exchangeable fraction of Cd in soils was mostly converted into carbonated-associated forms. The water soluble plus exchangeable fraction (SE) of Cd in soil decreased when treated with single and compound materials of sepiolite, bentonite and phosphate, which resulted in 13.2%-69.2% reduction compared with that of CK (control test). The amendments led to decreased Cd concentrations in roots, stems, leaves, brown rice, and rice hull by 16.2%-54.5%, 16.6%-42.8%, 19.6%-59.6%, 5.0%-68.2%, and 6.2%-20.4%, respectively. Higher bacterial and actinomycete amount indicated that remediation measures improved soil environmental quality. Composite amendments could be more efficiently used for the stabilization remediation of Cd contaminated soils with low Cd uptake and translocation in the plants and available contents of Cd in soil. PMID:26513318

  20. The voltage-sensor structure in a voltage-gated channel

    E-print Network

    Bezanilla, Francisco

    The voltage-sensor structure in a voltage-gated channel Francisco Bezanilla Departments in determining the molecular structure of the voltage sensor. The nerve impulse and voltage-dependent channels sensor and the last two of which form the conduction pore, which has been thoroughly characterized after

  1. Breakdown Characteristics of SF6 Gas under Non-Standard Lightning Impulse Voltage

    NASA Astrophysics Data System (ADS)

    Yuasa, Sadayuki; Okabe, Shigemitsu

    Evaluation of lightning surge waveforms that actually enter into substations is important to investigating the test voltage of gas insulated switchgear (GIS). The actual lightning surge waveforms in substations are different from the standard lightning impulse voltage because they are complex and are usually superimposed with various oscillations. This paper describes insulation characteristics in SF6 gas gap under the waveforms including oscillation (called waveforms B, C and D). The minimum breakdown voltages (Vmin) under experimental waveforms are higher than Vmin under the standard lightning impulse voltage. The evaluation method, which deals duration applied over 80% of peak voltage and conversion factor for second waves of waveform B, can estimate the insulation characteristics under waveforms B, C and D.

  2. A multilevel voltage-source converter system with balanced dc voltages

    SciTech Connect

    Peng, Fang Zheng; Lai, Jih-Sheng; McKeever, J.; VanCoevering, J.

    1995-04-01

    A multilevel voltage-source converter system is proposed for high-voltage, high-power applications such as large induction motor drives, back-to-back interconnected power systems, and electrical traction drives. Multilevel voltage-source converters have a voltage unbalance problem in the dc capacitors. The problem may be solved by use of additional voltage regulators or separate dc sources. However, these solutions are found not to be practicable for most applications. The proposed converter system can solve the voltage unbalance problem of the conventional multilevel voltage-source converters, without using any additional voltage balance circuits or separate voltage sources. Mechanism of the voltage unbalance problem is analyzed theoretically in this paper. The validity of the new converter system is demonstrated by simulation and experiment.

  3. A multilevel voltage-source converter system with balanced DC voltages

    NASA Astrophysics Data System (ADS)

    Peng, Fang Zheng; Lai, Jih-Sheng; McKeever, John; Vancoevering, James

    1995-05-01

    A multilevel voltage-source converter system is proposed for high-voltage, high-power applications such as large induction motor drives, back-to-back interconnected power systems, and electrical traction drives. Multilevel voltage-source converters have a voltage unbalance problem in the Direct Current (DC) capacitors. The problem may be solved by use of additional voltage regulators or separate dc sources. However, these solutions are found not to be practicable for most applications. The proposed converter system can solve the voltage unbalance problem of the conventional multilevel voltage-source converters, without using any additional voltage balance circuits or separate voltage sources. Mechanism of the voltage unbalance problem is analyzed theoretically in this paper. The validity of the new converter system is demonstrated by simulation and experiment.

  4. Comparative study of 0° X-cut and Y + 36°-cut lithium niobate high-voltage sensing

    NASA Astrophysics Data System (ADS)

    Patel, N.; Branch, D. W.; Schamiloglu, E.; Cular, S.

    2015-08-01

    A comparison study between Y + 36° and 0° X-cut lithium niobate (LiNbO3) was performed to evaluate the influence of crystal cut on the acoustic propagation to realize a piezoelectric high-voltage sensor. The acoustic time-of-flight for each crystal cut was measured when applying direct current (DC), alternating current (AC), and pulsed voltages. Results show that the voltage-induced shift in the acoustic wave propagation time scaled quadratically with voltage for DC and AC voltages applied to X-cut crystals. For the Y + 36° crystal, the voltage-induced shift scales linearly with DC voltages and quadratically with AC voltages. When applying 5 ?s voltage pulses to both crystals, the voltage-induced shift scaled linearly with voltage. For the Y + 36° cut, the voltage-induced shift from applying DC voltages ranged from 10 to 54 ps and 35 to 778 ps for AC voltages at 640 V over the frequency range of 100 Hz-100 kHz. Using the same conditions as the Y + 36° cut, the 0° X-cut crystal sensed a shift of 10-273 ps for DC voltages and 189-813 ps for AC voltage application. For 5 ?s voltage pulses, the 0° X-cut crystal sensed a voltage induced shift of 0.250-2 ns and the Y + 36°-cut crystal sensed a time shift of 0.115-1.6 ns. This suggests a frequency sensitive response to voltage where the influence of the crystal cut was not a significant contributor under DC, AC, or pulsed voltage conditions. The measured DC data were compared to a 1-D impedance matrix model where the predicted incremental length changed as a function of voltage. When the voltage source error was eliminated through physical modeling from the uncertainty budget, the combined uncertainty of the sensor (within a 95% confidence interval) decreased to 0.0033% using a Y + 36°-cut crystal and 0.0032% using an X-cut crystal for all the voltage conditions used in this experiment.

  5. Comparative study of 0° X-cut and Y + 36°-cut lithium niobate high-voltage sensing.

    PubMed

    Patel, N; Branch, D W; Schamiloglu, E; Cular, S

    2015-08-01

    A comparison study between Y + 36° and 0° X-cut lithium niobate (LiNbO3) was performed to evaluate the influence of crystal cut on the acoustic propagation to realize a piezoelectric high-voltage sensor. The acoustic time-of-flight for each crystal cut was measured when applying direct current (DC), alternating current (AC), and pulsed voltages. Results show that the voltage-induced shift in the acoustic wave propagation time scaled quadratically with voltage for DC and AC voltages applied to X-cut crystals. For the Y + 36° crystal, the voltage-induced shift scales linearly with DC voltages and quadratically with AC voltages. When applying 5 ?s voltage pulses to both crystals, the voltage-induced shift scaled linearly with voltage. For the Y + 36° cut, the voltage-induced shift from applying DC voltages ranged from 10 to 54 ps and 35 to 778 ps for AC voltages at 640 V over the frequency range of 100 Hz-100 kHz. Using the same conditions as the Y + 36° cut, the 0° X-cut crystal sensed a shift of 10-273 ps for DC voltages and 189-813 ps for AC voltage application. For 5 ?s voltage pulses, the 0° X-cut crystal sensed a voltage induced shift of 0.250-2 ns and the Y + 36°-cut crystal sensed a time shift of 0.115-1.6 ns. This suggests a frequency sensitive response to voltage where the influence of the crystal cut was not a significant contributor under DC, AC, or pulsed voltage conditions. The measured DC data were compared to a 1-D impedance matrix model where the predicted incremental length changed as a function of voltage. When the voltage source error was eliminated through physical modeling from the uncertainty budget, the combined uncertainty of the sensor (within a 95% confidence interval) decreased to 0.0033% using a Y + 36°-cut crystal and 0.0032% using an X-cut crystal for all the voltage conditions used in this experiment. PMID:26329223

  6. Low power, scalable multichannel high voltage controller

    DOEpatents

    Stamps, James Frederick (Livermore, CA); Crocker, Robert Ward (Fremont, CA); Yee, Daniel Dadwa (Dublin, CA); Dils, David Wright (Fort Worth, TX)

    2008-03-25

    A low voltage control circuit is provided for individually controlling high voltage power provided over bus lines to a multitude of interconnected loads. An example of a load is a drive for capillary channels in a microfluidic system. Control is distributed from a central high voltage circuit, rather than using a number of large expensive central high voltage circuits to enable reducing circuit size and cost. Voltage is distributed to each individual load and controlled using a number of high voltage controller channel switches connected to high voltage bus lines. The channel switches each include complementary pull up and pull down photo isolator relays with photo isolator switching controlled from the central high voltage circuit to provide a desired bus line voltage. Switching of the photo isolator relays is further controlled in each channel switch using feedback from a resistor divider circuit to maintain the bus voltage swing within desired limits. Current sensing is provided using a switched resistive load in each channel switch, with switching of the resistive loads controlled from the central high voltage circuit.

  7. Low power, scalable multichannel high voltage controller

    SciTech Connect

    Stamps, James Frederick; Crocker, Robert Ward; Yee, Daniel Dadwa; Dils, David Wright

    2006-03-14

    A low voltage control circuit is provided for individually controlling high voltage power provided over bus lines to a multitude of interconnected loads. An example of a load is a drive for capillary channels in a microfluidic system. Control is distributed from a central high voltage circuit, rather than using a number of large expensive central high voltage circuits to enable reducing circuit size and cost. Voltage is distributed to each individual load and controlled using a number of high voltage controller channel switches connected to high voltage bus lines. The channel switches each include complementary pull up and pull down photo isolator relays with photo isolator switching controlled from the central high voltage circuit to provide a desired bus line voltage. Switching of the photo isolator relays is further controlled in each channel switch using feedback from a resistor divider circuit to maintain the bus voltage swing within desired limits. Current sensing is provided using a switched resistive load in each channel switch, with switching of the resistive loads controlled from the central high voltage circuit.

  8. Dynamic Voltage Regulation Using Distributed Energy Resources

    SciTech Connect

    Xu, Yan; Rizy, D Tom; Li, Fangxing; Kueck, John D

    2007-01-01

    Many distributed energy resources (DE) are near load centres and equipped with power electronics converters to interface with the grid, therefore it is feasible for DE to provide ancillary services such as voltage regulation, nonactive power compensation, and power factor correction. A synchronous condenser and a microturbine with an inverter interface are implemented in parallel in a distribution system to regulate the local voltage. Voltage control schemes of the inverter and the synchronous condenser are developed. The experimental results show that both the inverter and the synchronous condenser can regulate the local voltage instantaneously, while the dynamic response of the inverter is faster than the synchronous condenser; and that integrated voltage regulation (multiple DE perform voltage regulation) can increase the voltage regulation capability, increase the lifetime of the equipment, and reduce the capital and operation costs.

  9. Voltage-Gated Sodium Channels

    NASA Astrophysics Data System (ADS)

    Hanck, Dorothy A.; Fozzard, Harry A.

    Voltage-gated sodium channels subserve regenerative excitation throughout the nervous system, as well as in skeletal and cardiac muscle. This excitation results from a voltage-dependent mechanism that increases regeneratively and selectively the sodium conductance of the channel e-fold for a 4-7 mV depolarization of the membrane with time constants in the range of tens of microseconds. Entry of Na+ into the cell without a companion anion depolarizes the cell. This depolarization, called the action potential, is propagated at rates of 1-20 meters/sec. In nerve it subserves rapid transmission of information and, in muscle cells, coordinates the trigger for contraction. Sodium-dependent action potentials depolarize the membrane to inside positive values of about 30-40 mV (approaching the electrochemical potential for the transmembrane sodium gradient). Repolarization to the resting potential (usually between -60 and -90 mV) occurs because of inactivation (closure) of sodium channels, which is assisted in different tissues by variable amounts of activation of voltage-gated potassium channels. This sequence results in all-or-nothing action potentials in nerve and fast skeletal muscle of 1-2 ms duration, and in heart muscle of 100-300 ms duration. Recovery of regenerative excitation, i.e., recovery of the ability of sodium channels to open, occurs after restoration of the resting potential with time constants of a few to several hundreds of milliseconds, depending on the channel isoform, and this rate controls the minimum interval for repetitive action potentials (refractory period).

  10. High voltage RF feedthrough bushing

    DOEpatents

    Grotz, Glenn F. (Huntington Station, NY)

    1984-01-01

    Described is a multi-element, high voltage radio frequency bushing for trmitting RF energy to an antenna located in a vacuum container. The bushing includes a center conductor of complex geometrical shape, an outer coaxial shield conductor, and a thin-walled hollow truncated cone insulator disposed between central and outer conductors. The shape of the center conductor, which includes a reverse curvature portion formed of a radially inwardly directed shoulder and a convex portion, controls the uniformity of the axial surface gradient on the insulator cone. The outer shield has a first substantially cylindrical portion and a second radially inwardly extending truncated cone portion.

  11. High Voltage TAL Erosion Characterization

    NASA Technical Reports Server (NTRS)

    Jacobson, David T.

    2003-01-01

    Extended operation of a D-80 anode layer thruster at high voltage was investigated. The thruster was operated for 1200 hours at 700 Volts and 4 Amperes. Laser profilometry was employed to quantify the erosion of the thruster's graphite guard rings and electrodes at 0, 300, 600, 900, and 1200 hours. Thruster performance and electrical characteristics were monitored over the duration of the investigation. The guard rings exhibited asymmetric erosion that was greatest in the region of the cathode. Erosion of the guard rings exposed the magnet poles between 600 to 900 hours of operation.

  12. 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. PMID:26106579

  13. Soil stabilization 1982

    NASA Astrophysics Data System (ADS)

    Barenberg, E. J.; Thompson, M. R.; Tayabji, S. D.; Nussbaum, P. J.; Ciolko, A. T.

    Seven papers cover the following areas: design, construction and performance of lime, fly ash, and slag pavement; evaluation of heavily loaded cement stabilized bases; coal refuse and fly ash compositions; potential highway base course materials; lime soil mixture design considerations for soils of southeastern United States; short term active soil property changes caused by injection of lime and fly ash; soil cement for use in stream channel grade stabilization structures; and reaction products of lime treated southeastern soils.

  14. 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.

  15. Sucrose ester stabilized solid lipid nanoparticles and nanostructured lipid carriers: II. Evaluation of the imidazole antifungal drug-loaded nanoparticle dispersions and their gel formulations

    NASA Astrophysics Data System (ADS)

    Das, Surajit; Kiong Ng, Wai; Tan, Reginald B. H.

    2014-03-01

    This study focused on: (i) feasibility of the previously developed sucrose ester stabilized SLNs and NLCs to encapsulate different imidazole antifungal drugs and (ii) preparation and evaluation of topical gel formulations of those SLNs and NLCs. Three imidazole antifungal drugs; clotrimazole, ketoconazole and climbazole were selected for this study. The results suggested that size, size distribution and drug encapsulation efficiency depend on the drug molecule and type of nanoparticles (SLN/NLC). The drug release experiment always showed faster drug release from NLCs than SLNs when the same drug molecule was loaded in both nanoparticles. However, drug release rate from both SLNs and NLCs followed the order of climbazole > ketoconazole > clotrimazole. NLCs demonstrated better physicochemical stability than SLNs in the case of all drugs. The drug release rate from ketoconazole- and clotrimazole-loaded SLNs became faster after three months than a fresh formulation. There was no significant change in drug release rate from climbazole-loaded SLNs and all drug-loaded NLCs. Gel formulations of SLNs and NLCs were prepared using polycarbophil polymer. Continuous flow measurements demonstrated non-Newtonian flow with shear-thinning behavior and thixotropy. Oscillation measurements depicted viscoelasticity of the gel formulations. Similar to nanoparticle dispersion, drug release rate from SLN- and NLC-gel was in the order of climbazole > ketoconazole > clotrimazole. However, significantly slower drug release was noticed from all gel formulations than their nanoparticle counterparts. Unlike nanoparticle dispersions, no significant difference in drug release from gel formulations containing SLNs and NLCs was observed for each drug. This study concludes that gel formulation of imidazole drug-loaded SLNs and NLCs can be used for sustained/prolonged topical delivery of the drugs.

  16. 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%.

  17. Functional heterogeneity of the four voltage sensors of a human L-type calcium channel

    PubMed Central

    Pantazis, Antonios; Savalli, Nicoletta; Sigg, Daniel; Neely, Alan; Olcese, Riccardo

    2014-01-01

    Excitation-evoked Ca2+ influx is the fastest and most ubiquitous chemical trigger for cellular processes, including neurotransmitter release, muscle contraction, and gene expression. The voltage dependence and timing of Ca2+ entry are thought to be functions of voltage-gated calcium (CaV) channels composed of a central pore regulated by four nonidentical voltage-sensing domains (VSDs I–IV). Currently, the individual voltage dependence and the contribution to pore opening of each VSD remain largely unknown. Using an optical approach (voltage-clamp fluorometry) to track the movement of the individual voltage sensors, we discovered that the four VSDs of CaV1.2 channels undergo voltage-evoked conformational rearrangements, each exhibiting distinct voltage- and time-dependent properties over a wide range of potentials and kinetics. The voltage dependence and fast kinetic components in the activation of VSDs II and III were compatible with the ionic current properties, suggesting that these voltage sensors are involved in CaV1.2 activation. This view is supported by an obligatory model, in which activation of VSDs II and III is necessary to open the pore. When these data were interpreted in view of an allosteric model, where pore opening is intrinsically independent but biased by VSD activation, VSDs II and III were each found to supply ?50 meV (?2 kT), amounting to ?85% of the total energy, toward stabilizing the open state, with a smaller contribution from VSD I (?16 meV). VSD IV did not appear to participate in channel opening. PMID:25489110

  18. Low Voltage Electrowetting Optical Deflector

    NASA Astrophysics Data System (ADS)

    Chen, Hsiu-Hsiang; Fu, Chien-Chung

    2011-03-01

    This paper demonstrates a low-operating-voltage electrowetting optical deflector (EOD) by reducing the interfacial surface tension between the electrolyte and the surrounding ambience. The goal of this study was to explore various approaches to achieving a low operating voltage. First, two kinds of fluoropolymers (Teflon® AF1601 and Cytop® CTL-809M) were utilized to confirm the thickness effect and wettability. Second, three different dielectric layers (SiO2, Si3N4, and Ta2O5) with the same thickness were tested to confirm the dielectric constant effect. Finally, three different surfactants (sodium dodecyl sulfate (SDS), Triton X100, and Triton X15) were used to confirm the interfacial surface tension effect. In this article, we demonstrate that the contact angle of water can change as much as 70° in a dodecane/water/Cytop®/Ta2O5 system (containing 1% SDS) with 11 V; furthermore, switchable apex angles of ˜±20° and deflection of a beam passing through the meniscus of EOD are presented.

  19. Multi-Objective Differential Evolution for Voltage Security Constrained Optimal Power Flow in Deregulated Power Systems

    NASA Astrophysics Data System (ADS)

    Roselyn, J. Preetha; Devaraj, D.; Dash, Subhransu Sekhar

    2013-11-01

    Voltage stability is an important issue in the planning and operation of deregulated power systems. The voltage stability problems is a most challenging one for the system operators in deregulated power systems because of the intense use of transmission line capabilities and poor regulation in market environment. This article addresses the congestion management problem avoiding offline transmission capacity limits related to voltage stability by considering Voltage Security Constrained Optimal Power Flow (VSCOPF) problem in deregulated environment. This article presents the application of Multi Objective Differential Evolution (MODE) algorithm to solve the VSCOPF problem in new competitive power systems. The maximum of L-index of the load buses is taken as the indicator of voltage stability and is incorporated in the Optimal Power Flow (OPF) problem. The proposed method in hybrid power market which also gives solutions to voltage stability problems by considering the generation rescheduling cost and load shedding cost which relieves the congestion problem in deregulated environment. The buses for load shedding are selected based on the minimum eigen value of Jacobian with respect to the load shed. In the proposed approach, real power settings of generators in base case and contingency cases, generator bus voltage magnitudes, real and reactive power demands of selected load buses using sensitivity analysis are taken as the control variables and are represented as the combination of floating point numbers and integers. DE/randSF/1/bin strategy scheme of differential evolution with self-tuned parameter which employs binomial crossover and difference vector based mutation is used for the VSCOPF problem. A fuzzy based mechanism is employed to get the best compromise solution from the pareto front to aid the decision maker. The proposed VSCOPF planning model is implemented on IEEE 30-bus system, IEEE 57 bus practical system and IEEE 118 bus system. The pareto optimal front obtained from MODE is compared with reference pareto front and the best compromise solution for all the cases are obtained from fuzzy decision making strategy. The performance measures of proposed MODE in two test systems are calculated using suitable performance metrices. The simulation results show that the proposed approach provides considerable improvement in the congestion management by generation rescheduling and load shedding while enhancing the voltage stability in deregulated power system.

  20. Evaluation of the Effect of Surface Polishing, Oral Beverages and Food Colorants on Color Stability and Surface Roughness of Nanocomposite Resins

    PubMed Central

    Kumari, R Veena; Nagaraj, Hema; Siddaraju, Kishore; Poluri, Ramya Krishna

    2015-01-01

    Background: It is beyond doubt that finishing and polishing of a composite restoration enhance its esthetics and, is also essential for the health of the periodontium. A variety of instruments are commonly used for finishing and polishing tooth-colored restorative materials Thus, it is important to understand which type of surface finishing treatments would significantly affect the staining and surface irregularities of the composite resin restoration. Still one of the properties of the composite resins that have to pass the test of time is its color stability. In modern day dentistry, a large emphasis is laid over esthetics. Hence, it is important to understand the various agents capable of adversely affecting the esthetics of a restoration due to its staining capacity. Thus, the aim of this in vitro study was to evaluate the effect of surface polishing, oral beverages and food colorants on the color stability and surface roughness of nanocomposite resins. Materials and Methods: 90 Disks of nanocomposites resin (Filtek Z350 XT) measuring 8 mm in diameter and 2 mm in thickness were fabricated using a custom made silicon mold. Pre-polishing surface roughness (Ra1) of all the 90 samples were measured using a Surface Profilometer. The nano-composite disks were then randomly divided into 3 groups with 30 samples in each group. Group I: Control group: The samples were not subjected to any polishing procedures. Group II: Sof-Lex group: Samples subjected to polishing using different grits of Sof-Lex disks. Group III: Diamond polishing paste group: Samples were subjected with a polishing paste consisting of diamond particles. Following polishing procedures, the surface roughness of all samples were measured again to obtain change in surface roughness due to polishing procedures (Ra2), pre immersion spectrophotometric value (?E1) was also recorded for baseline color of the samples. The samples were then divided into subgroups (A, B, C, D, E), by including every first sample in Subgroup A, second in Subgroup B, third in Subgroup C, fourth in Subgroup D, and fifth in Subgroup E. Each was immersed in the respective test solution for 10 min, twice a day for 30 days. Group A - Tea, Group B - Coffee, Group C - Cola, Group D - Turmeric, Group E - Control (artificial saliva). Post immersion profilometric value was recorded to evaluate roughness bought about by the solutions (Ra3) and spectrophotometric value was recorded to evaluate the color change in samples (?E2). Results were statistically analyzed using ANOVA. Results: Higher mean roughness (Ra2-Ra1) value was recorded in Sof-Lex, followed by Diamond polishing paste and Control group. Comparison of surface roughness caused due to beverages and food colorant solution showed subgroup C (Coca Cola) increased surface roughness in all groups (Group I, II, III). Subgroup D (Turmeric) had the highest discoloration potential (P < 0001) in all groups, followed by coffee, tea, coca-cola and artificial saliva. Sof-Lex polishing System showed most color stability. Conclusion: Polishing procedures significantly roughen the surface of the restoration compared to the unpolished Mylar controls. One-step polishing system (diamond polishing paste) produces a smoother surface compared to a multi-step system (Sof-Lex polishing disks). Turmeric solution caused maximum staining of the samples, to a visually perceptible level. PMID:26229373