WorldWideScience

Sample records for voltage difference applied

  1. Spatial and Excitation Variations for Different Applied Voltages in an Atmospheric Neon Plasma Jet

    Science.gov (United States)

    Yang, Lanlan; Tu, Yan; Yu, Yongbo; Hu, Dinglan; Zhang, Xiong

    2016-09-01

    A neon plasma jet was generated in air, driven by a 9 kHz sinusoidal power supply. The characteristics of the plasma plume and the optical spectra with plasma propagation for different applied voltages were investigated. By increasing the applied voltage, the plasma plume first increases and then retracts to become short and bulky. The shortened effect of Ne plasma plume (about 10 mm) for the further voltage increasing is more apparent than that of He (about 3 mm) and Ar (about 1 mm). Emission intensity of the N2 (337 nm) increases with the applied voltage, gradually substituting the emission intensity of Ne (702 nm and 585 nm) as the noticeable radiation. At the nozzle opening, the Ne (702 nm) emission dominates, while the Ne (585 nm) emission is most noticeable around the tip of the plasma plume. The spatial distribution of the three spectral lines indicates that Ne (702 nm) emission decreases dramatically with plasma propagation while Ne (585 nm) and N2 (337 nm) emissions reach their maxima at the middle of the plasma plume. The results indicate that the Ne (702 nm) emission is much more sensitive to the average electron temperature and the density of the high-energy electrons, so it changes greatly at the tube nozzle and little at the tip region as the voltage increases. The population of high-energy electrons, the average electron temperature, the collision with air molecules and the Penning effect between Ne metastables and air molecules may explain their different variations with plasma propagating and voltage increasing. supported by National Natural Science Fundation of China (No. 61271053), the Natural Science Foundation of Jiangsu Province of China (No. BK2012737), the Foundation for Excellent Youth Scholars of Southeast University, China

  2. Characteristics of titanium dioxide nanostructures synthesized via electrochemical anodization at different applied voltages

    Energy Technology Data Exchange (ETDEWEB)

    Cheong, Y. L.; Yam, F. K.; Hassan, Z. [Nano-Optoelectronics Research and Technology Laboratory School of Physics, Universiti Sains Malaysia, 11800 Penang (Malaysia)

    2015-05-15

    This paper presents the study of the growth of nanostructure titanium dioxide (TiO{sub 2}) via electrochemical anodization method. Both constant and alternating anodization voltage would be applied in this study. The effects of applied voltage on the morphological and structural properties were studied. Images of field emission scanning electron microscope (FE-SEM) revealed that morphology of nanostructure could be manipulated by changing the type and amount of applied voltage. Besides that, X-ray diffraction (XRD) results indicated that crystalline structures (anatase and rutile) could be obtained after being annealed at 700°C for 60 minutes. By analysing the data in XRD measurements, crystallite size of the TiO{sub 2} could be calculated by using the Scherrer method. Besides that, the relationship between mean crystallites sizes and anodization voltage would also be further studied in this paper.

  3. Electric Double-Layer Capacitors Applying to Voltage Sag Compensator

    Science.gov (United States)

    Nara, Hidetaka

    Recently the electric double-layer capacitor (EDLC) which is rapidly charged and discharged and offers long life, maintenance-free, has been developed as a new energy storage element. Therefore, we developed the uninterruptible power supply as voltage sag compensator utilizing EDLC. This paper describes an abstract of EDLC and applying to voltage sag compensation.

  4. Transverse voltage in superconductors at zero applied magnetic field

    Energy Technology Data Exchange (ETDEWEB)

    Luz, M.S. da [Escola de Engenharia de Lorena - USP, P.O. Box 116, Lorena, SP 12602-810 (Brazil)], E-mail: luz@physics.montana.edu; Santos, C.A.M. dos; Shigue, C.Y.; Carvalho, F.J.H. de; Machado, A.J.S. [Escola de Engenharia de Lorena - USP, P.O. Box 116, Lorena, SP 12602-810 (Brazil)

    2009-01-01

    A systematic study of the transverse voltage at zero magnetic field in the superconducting state is reported. The effects of warming rate, temperature, applied magnetic field, and electrical current on the transversal resistance (R{sub XY}) of polycrystalline superconducting sample are taken into account. At zero magnetic field two peaks are observed in R{sub XY}(T) curves which are related to the double superconducting transition in the R{sub XX}(T) component. In the superconducting (R{sub XX} = zero) and normal states no transverse voltage has been detected at zero magnetic field as expected. The results are discussed within the framework of the motion of Abrikosov and Josephson vortices and anti-vortices. A new scaling relation between transverse and longitudinal components given by R{sub XY} {approx} dR{sub XX}/dT has been confirmed.

  5. Power conditioning using dynamic voltage restorers under different voltage sag types

    Directory of Open Access Journals (Sweden)

    Ahmed M. Saeed

    2016-01-01

    Full Text Available Voltage sags can be symmetrical or unsymmetrical depending on the causes of the sag. At the present time, one of the most common procedures for mitigating voltage sags is by the use of dynamic voltage restorers (DVRs. By definition, a DVR is a controlled voltage source inserted between the network and a sensitive load through a booster transformer injecting voltage into the network in order to correct any disturbance affecting a sensitive load voltage. In this paper, modelling of DVR for voltage correction using MatLab software is presented. The performance of the device under different voltage sag types is described, where the voltage sag types are introduced using the different types of short-circuit faults included in the environment of the MatLab/Simulink package. The robustness of the proposed device is evaluated using the common voltage sag indices, while taking into account voltage and current unbalance percentages, where maintaining the total harmonic distortion percentage of the load voltage within a specified range is desired. Finally, several simulation results are shown in order to highlight that the DVR is capable of effective correction of the voltage sag while minimizing the grid voltage unbalance and distortion, regardless of the fault type.

  6. Power conditioning using dynamic voltage restorers under different voltage sag types.

    Science.gov (United States)

    Saeed, Ahmed M; Abdel Aleem, Shady H E; Ibrahim, Ahmed M; Balci, Murat E; El-Zahab, Essam E A

    2016-01-01

    Voltage sags can be symmetrical or unsymmetrical depending on the causes of the sag. At the present time, one of the most common procedures for mitigating voltage sags is by the use of dynamic voltage restorers (DVRs). By definition, a DVR is a controlled voltage source inserted between the network and a sensitive load through a booster transformer injecting voltage into the network in order to correct any disturbance affecting a sensitive load voltage. In this paper, modelling of DVR for voltage correction using MatLab software is presented. The performance of the device under different voltage sag types is described, where the voltage sag types are introduced using the different types of short-circuit faults included in the environment of the MatLab/Simulink package. The robustness of the proposed device is evaluated using the common voltage sag indices, while taking into account voltage and current unbalance percentages, where maintaining the total harmonic distortion percentage of the load voltage within a specified range is desired. Finally, several simulation results are shown in order to highlight that the DVR is capable of effective correction of the voltage sag while minimizing the grid voltage unbalance and distortion, regardless of the fault type.

  7. Condition for the occurrence of phase slip centers in superconducting nanowires under applied current or voltage

    DEFF Research Database (Denmark)

    Michotte, S.; Mátéfi-Tempfli, Stefan; Piraux, L.;

    2004-01-01

    Experimental results on the phase slip process in superconducting lead nanowires are presented under two different experimental conditions: constant applied current or constant voltage. Based on these experiments we established a simple model which gives us the condition of the appearance of phas...

  8. Applied-voltage dependence on conductometric track etching of poly(vinylidene fluoride) films

    Energy Technology Data Exchange (ETDEWEB)

    Nuryanthi, N. [Department of Nuclear Engineering and Management, School of Engineering, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656 (Japan); Quantum Beam Science Directorate, Japan Atomic Energy Agency, 1233 Watanuki, Takasaki, Gunma 370-1292 (Japan); Yamaki, T., E-mail: yamaki.tetsuya@jaea.go.jp [Quantum Beam Science Directorate, Japan Atomic Energy Agency, 1233 Watanuki, Takasaki, Gunma 370-1292 (Japan); Koshikawa, H.; Asano, M.; Sawada, S.; Hasegawa, S.; Maekawa, Y. [Quantum Beam Science Directorate, Japan Atomic Energy Agency, 1233 Watanuki, Takasaki, Gunma 370-1292 (Japan); Katsumura, Y. [Department of Nuclear Engineering and Management, School of Engineering, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656 (Japan)

    2013-11-01

    We investigated the conductometric etching of heavy-ion-irradiated poly(vinylidene fluoride) (PVDF) films to study their pore growth behavior, which was estimated from radial etch rates under the application of different voltages. The plateau of the pore diameter seen in a bulk etching region was constant at an applied voltage ranging from 0.1 to 3.0 V, while the breakthrough time varied considerably. Employing the first derivative of the conductometric curve, corresponding to the radial etch rate, R, enabled us to clearly analyze parameters reflecting the track structures (i.e., the maximum radial etch rate, R{sub max}, and the time for the diameter to reach the final plateau, T{sub E}). Interestingly, these two parameters were significantly influenced by the applied voltage. There was a trend toward increasing values of R{sub max} and, in contrast, decreasing levels of T{sub E} as the applied voltage was increased. These promotional effects of the etching process can be rationalized by considering the electrophoretic migration of dissolved species in and out of each pore. Thus, conductometric etching under different voltage conditions offers the ability to control pore geometries by optimizing the etching process in the transverse direction as well as in the thickness direction.

  9. New Control Technique Applied in Dynamic Voltage Restorer for Voltage Sag Mitigation

    Directory of Open Access Journals (Sweden)

    Rosli Omar

    2010-01-01

    Full Text Available The Dynamic Voltage Restorer (DVR was a power electronics device that was able to compensate voltage sags on critical loads dynamically. The DVR consists of VSC, injection transformers, passive filters and energy storage (lead acid battery. By injecting an appropriate voltage, the DVR restores a voltage waveform and ensures constant load voltage. There were so many types of the control techniques being used in DVR for mitigating voltage sags. The efficiency of the DVR depends on the efficiency of the control technique involved in switching the inverter. Problem statement: Simulation and experimental investigation toward new algorithms development based on SVPWM. Understanding the nature of DVR and performance comparisons between the various controller technologies available. The proposed controller using space vector modulation techniques obtain higher amplitude modulation indexes if compared with conventional SPWM techniques. Moreover, space vector modulation techniques can be easily implemented using digital processors. Space vector PWM can produce about 15% higher output voltage than standard Sinusoidal PWM. Approach: The purpose of this research was to study the implementation of SVPWM in DVR. The proposed control algorithm was investigated through computer simulation by using PSCAD/EMTDC software. Results: From simulation and experimental results showed the effectiveness and efficiency of the proposed controller based on SVPWM in mitigating voltage sags in low voltage distribution systems. It was concluded that its controller also works well both in balance and unbalance conditions of voltages. Conclusion/Recommendations: The simulation and experimental results of a DVR using PSCAD/EMTDC software based on SVPWM technique showed clearly the performance of the DVR in mitigating voltage sags. The DVR operates without any difficulties to inject the appropriate voltage component to correct rapidly any anomaly in the supply voltage to keep the

  10. Multifunction Voltage-Mode Filter Using Single Voltage Differencing Differential Difference Amplifier

    Directory of Open Access Journals (Sweden)

    Chaichana Amornchai

    2017-01-01

    Full Text Available In this paper, a voltage mode multifunction filter based on single voltage differencing differential difference amplifier (VDDDA is presented. The proposed filter with three input voltages and single output voltage is constructed with single VDDDA, two capacitors and two resistors. Its quality factor can be adjusted without affecting natural frequency. Also, the natural frequency can be electronically tuned via adjusting of bias current. The filter can offer five output responses, high-pas (HP, band-pass (BP, band-reject (BR, low-pass (LP and all-ass (AP functions in the same circuit topology. The output response can be selected by choosing the suitable input voltage without the component matching condition and the requirement of additional double gain voltage amplifier. PSpice simulation results to confirm an operation of the proposed filter correspond to the theory.

  11. Simulation of subnanosecond streamers in atmospheric-pressure air: Effects of polarity of applied voltage pulse

    Science.gov (United States)

    Babaeva, N. Yu.; Naidis, G. V.

    2016-08-01

    Results of simulation of subnanosecond streamer propagation in corona gap configuration, obtained in the framework of 2D fluid model, are presented. Effects related with the polarity of a voltage pulse applied to the stressed electrode are discussed. It is argued that these effects (dependence of the discharge current and propagation velocity on the polarity of applied voltage) observed in experiments can be attributed to the difference in initial (preceding the streamer formation) distributions of charged species inside the gap. This difference can be caused by preionization (at negative polarity) of the gas inside the discharge gap by runaway electrons. Calculated streamers have large widths (up to 1 cm) and move with velocities in the range of 109-1010 cm s-1, similar to experimental data.

  12. Relationships between Harmonic Characteristics and Different Types of Voltage Source

    Directory of Open Access Journals (Sweden)

    Yusniati Yusniati

    2012-06-01

    Full Text Available This paper discusses about harmonic characteristics due to different types of voltage sources. Usually, the voltage source is sinusoidal. But in actual condition the load that receive voltage sources through the elements where the output voltage of element as input to the load is not pure sinusoidal, for example voltage source at  (PCC between transformer and linear load and nonlinear load. This research has been done with Schhafner Power Quality Analyzer and PM300 Power Quality Analyzer, was focused to all harmonic characteristics as power, voltage, current, power factor (p.f., Harmonic Distortion, and harmonic energy losses cost. The load is Induction Motor with Adjustable Speed Drive (ASD because the Induction Motor with Adjustable Speed Drive (ASD is one of electronic device causes harmonics. The voltage sources in this research are sine wave, square wave and harmonic order combinations of 3rd, 5th and 7th which can create from Schhafner Power Quality Analyzer.

  13. Relationships between Harmonic Characteristics and Different Types of Voltage Source

    Directory of Open Access Journals (Sweden)

    Syafruddin H

    2012-06-01

    Full Text Available This paper discusses about harmonic characteristics due to different types of voltage sources. Usually, the voltage source is sinusoidal. But in actual condition the load that receive voltage sources through the elements where the output voltage of element as input to the load is not pure sinusoidal, for example voltage source at  (PCC between transformer and linear load and nonlinear load. This research has been done with Schhafner Power Quality Analyzer and PM300 Power Quality Analyzer, was focused to all harmonic characteristics as power, voltage, current, power factor (p.f., Harmonic Distortion, and harmonic energy losses cost. The load is Induction Motor with Adjustable Speed Drive (ASD because the Induction Motor with Adjustable Speed Drive (ASD is one of electronic device causes harmonics. The voltage sources in this research are sine wave, square wave and harmonic order combinations of 3rd, 5th and 7th which can create from Schhafner Power Quality Analyzer.

  14. BiasMDP: Carrier lifetime characterization technique with applied bias voltage

    Energy Technology Data Exchange (ETDEWEB)

    Jordan, Paul M., E-mail: paul.jordan@namlab.com; Simon, Daniel K.; Dirnstorfer, Ingo [Nanoelectronic Materials Laboratory gGmbH (NaMLab), Nöthnitzer Straße 64, 01187 Dresden (Germany); Mikolajick, Thomas [Nanoelectronic Materials Laboratory gGmbH (NaMLab), Nöthnitzer Straße 64, 01187 Dresden (Germany); Technische Universität Dresden, Institut für Halbleiter- und Mikrosystemtechnik, 01062 Dresden (Germany)

    2015-02-09

    A characterization method is presented, which determines fixed charge and interface defect densities in passivation layers. This method bases on a bias voltage applied to an electrode on top of the passivation layer. During a voltage sweep, the effective carrier lifetime is measured by means of microwave detected photoconductivity. When the external voltage compensates the electric field of the fixed charges, the lifetime drops to a minimum value. This minimum value correlates to the flat band voltage determined in reference impedance measurements. This correlation is measured on p-type silicon passivated by Al{sub 2}O{sub 3} and Al{sub 2}O{sub 3}/HfO{sub 2} stacks with different fixed charge densities and layer thicknesses. Negative fixed charges with densities of 3.8 × 10{sup 12 }cm{sup −2} and 0.7 × 10{sup 12 }cm{sup −2} are determined for Al{sub 2}O{sub 3} layers without and with an ultra-thin HfO{sub 2} interface, respectively. The voltage and illumination dependencies of the effective carrier lifetime are simulated with Shockley Read Hall surface recombination at continuous defects with parabolic capture cross section distributions for electrons and holes. The best match with the measured data is achieved with a very low interface defect density of 1 × 10{sup 10 }eV{sup −1} cm{sup −2} for the Al{sub 2}O{sub 3} sample with HfO{sub 2} interface.

  15. The study of surface wetting, nanobubbles and boundary slip with an applied voltage: A review

    Directory of Open Access Journals (Sweden)

    Yunlu Pan

    2014-07-01

    Full Text Available The drag of fluid flow at the solid–liquid interface in the micro/nanoscale is an important issue in micro/nanofluidic systems. Drag depends on the surface wetting, nanobubbles, surface charge and boundary slip. Some researchers have focused on the relationship between these interface properties. In this review, the influence of an applied voltage on the surface wettability, nanobubbles, surface charge density and slip length are discussed. The contact angle (CA and contact angle hysteresis (CAH of a droplet of deionized (DI water on a hydrophobic polystyrene (PS surface were measured with applied direct current (DC and alternating current (AC voltages. The nanobubbles in DI water and three kinds of saline solution on a PS surface were imaged when a voltage was applied. The influence of the surface charge density on the nanobubbles was analyzed. Then the slip length and the electrostatic force on the probe were measured on an octadecyltrichlorosilane (OTS surface with applied voltage. The influence of the surface charge on the boundary slip and drag of fluid flow has been discussed. Finally, the influence of the applied voltage on the surface wetting, nanobubbles, surface charge, boundary slip and the drag of liquid flow are summarized. With a smaller surface charge density which could be achieved by applying a voltage on the surface, larger and fewer nanobubbles, a larger slip length and a smaller drag of liquid flow could be found.

  16. Impedance of goat eye lens at different DC voltages.

    Science.gov (United States)

    Kohli, K S; Rai, D V; Jindal, V K; Goyal, N

    1998-09-01

    A computer assisted AC impedance system is used to measure the DC voltage-current (V-I) characteristics and AC impedance of a goat eye lens using a two-probe Ag-AgCl electrode system. The measurement of the V-I characteristics shows that when a DC voltage from 0 mV to 30 mV is applied, the resultant current decreases from an initial value of 0.58 microA to 0.006 microA. However, when the voltage is increases beyond 30 mV, the current increases and reaches a value of 0.9 microA at 100 mV. The data on the frequency response (0.01-10 Hz) of the impedance of lens tissue show an inverse relationship with frequency. The effect of various DC voltages, namely 0, 30, 50, 100 and 200 mV, on the impedance of the eye lens is also investigated over a frequency range of 0.01-10 Hz. The measurement results for both V-I characteristics and AC impedance further suggest the presence of a 30 mV voltage compartment in the goat eye lens.

  17. All-optical detection of magnetization precession in tunnel junctions under applied voltage

    Science.gov (United States)

    Sasaki, Yuta; Suzuki, Kazuya; Sugihara, Atsushi; Kamimaki, Akira; Iihama, Satoshi; Ando, Yasuo; Mizukami, Shigemi

    2017-02-01

    An all-optical time-resolved magneto-optical Kerr effect measurement of a micron-sized tunnel junction with a CoFeB electrode was performed. The femtosecond (fs) laser-induced magnetization precession was clearly observed at various magnetic field angles. The frequency f and relaxation time τ of the magnetization precession varied with the voltage applied via a MgO barrier. The precession dynamics were in accordance with Kittel’s ferromagnetic resonance mode, and the voltage-induced changes in f and τ were well explained by the voltage-induced change in the perpendicular magnetic anisotropy of -36 fJ/Vm.

  18. Effect of a longitudinally applied voltage upon the growth of Zea mays seedlings

    Science.gov (United States)

    Desrosiers, M. F.; Bandurski, R. S.

    1988-01-01

    The electrical parameters that affect young seedling growth were investigated. Voltages ranging from 5 to 40 volts were applied longitudinally along the mesocotyl region of 4-day old Zea mays L. (cv Silver Queen) seedlings for periods of 3 or 4 hours. It was determined that: (a) making the tips of the seedlings electrically positive relative to the base strongly inhibited shoot growth at 5 volts, whereas the reverse polarity had no effect; (b) at higher voltages, making the tip of the seedlings negative caused less growth inhibition than the reverse polarity at each voltage level; (c) the higher the applied voltage the greater the degree of inhibition; and, (d) the more growth inhibition experienced by the plants the poorer, and slower, their recovery. Previous observations of a relationship between the amount of free indole-3-acetic acid in the mesocotyl cortex and the growth rate of the mesocotyl and of gravitropism-induced movement of labeled indole-3-acetic acid from the seed to the shoot lead to the prediction of a voltage-dependent gating of the movement of indole-3-acetic acid from the stele to the cortex. This provided the basis for attempting to alter the growth rate of seedlings by means of an applied voltage.

  19. Perspectives on low voltage transmission electron microscopy as applied to cell biology.

    Science.gov (United States)

    Bendayan, Moise; Paransky, Eugene

    2014-12-01

    Low voltage transmission electron microscopy (LVTEM) with accelerating voltages as low as 5 kV was applied to cell biology. To take advantage of the increased contrast given by LVTEM, tissue preparation was modified omitting all heavy metals such as osmium, uranium, and lead from the fixation, on block staining and counterstaining. Nonstained ultra-thin tissue sections (40 nm thick) generated highly contrasted images. While the aspect of the cells remains similar to that obtained by conventional TEM, some new substructures were revealed. The pancreatic acinar cells granules present a heterogeneous matrix with partitions corresponding to segregation of their different secretory proteins. Microvilli display their core of microfilaments anchored to the dense top membrane. Mitochondria revealed the presence of distinct particles along their cristea membranes that may correspond to the ATP synthase complexes or oxysomes. The dense nuclear chromatin displays a honey-comb appearance while distinct beads aligned along thin threads were seen in the dispersed chromatin. These new features revealed by LVTEM correlate with structures described or predicted through other approaches. Masking effects due to thickness of the tissue sections and to the presence of heavy metals must have prevented their observation by conventional TEM. Furthermore, the immunogold was adapted to LVTEM revealing nuclear lamin-A at the edge of the dense chromatin ribbons. Combining cytochemistry with LVTEM brings additional advantages to this new approach in cell biology.

  20. Effect of applied dc bias voltage on composition, chemical bonding and mechanical properties of carbon nitride films prepared by PECVD

    Institute of Scientific and Technical Information of China (English)

    LI Hong-xuan; XU Tao; HAO Jun-ying; CHEN Jian-min; ZHOU Hui-di; XUE Qun-ji; LIU Hui-wen

    2004-01-01

    Carbon nitride films were deposited on Si (100) substrates using plasma-enhanced chemical vapor deposition (PECVD) technique from CH4 and N2 at different applied dc bias voltage. The microstructure, composition and chemical bonding of the resulting films were characterized by Raman spectroscopy, Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS) and X-ray diffraction (XRD). The mechanical properties such as hardness and elastic modulus of the films were evaluated using nano-indentation. As the results, the Raman spectra, showing the G and D bands, indicate the amorphous structure of the films. XPS and FTIR measurements demonstrate the existence of various carbon-nitride bonds in the films and the hydrogenation of carbon nitride phase. The composition ratio of N to C, the nano-hardness and the elastic modulus of the carbon nitride films increase with increasing dc bias voltage and reach the maximums at a dc bias voltage of 300 V, then they decrease with further increase of the dc bias voltage. Moreover, the XRD analyses indicate that the carbon nitride film contains some polycrystalline C3N4 phase embedded in the amorphous matrix at optimized deposition condition of dc bias voltage of 300 V.

  1. Investigation of the effects caused by applying voltage in Layer-by-Layer self-assembly method

    Directory of Open Access Journals (Sweden)

    Omura Y.

    2013-08-01

    Full Text Available Recently, Layer-by-Layer (LbL self-assembly method under applied voltage (voltage-applied LbL attracts great attention. It is reported that the method enables more abundant film adsorption than conventional LbL method. However, a small proportion of experimental results about adsorption of polyelectrolytes by voltage-applied LbL have been reported. In this study, voltage-applied LbL method using weakly charged polyelectrolytes was examined. Poly (allylamine hydrochloride (PAH and Poly (ethylene imine (PEI as cationic solutions and Poly (acrylic acid (PAA as anionic solution were chosen. The pH of solutions was adjusted to several conditions and film of PAH/PAA and film of PEI/PAA were fabricated by voltage-applied LbL method. Change of adsorption behavior and film morphology by applying voltage depended on pH condition of solutions. When pH of PAH/PAA solutions was 3.9/3.8, respectively, the film adsorption was accelerated by applying voltage. Moreover, in this condition, the surface morphology remarkably changes and texture structure appears by applying voltage. Consequently, it was found that applying voltage in LbL method was effective in controlling film adsorption and the surface nano structure.

  2. Fast switching thyristor applied in nanosecond-pulse high-voltage generator with closed transformer core.

    Science.gov (United States)

    Li, Lee; Bao, Chaobing; Feng, Xibo; Liu, Yunlong; Fochan, Lin

    2013-02-01

    For a compact and reliable nanosecond-pulse high-voltage generator (NPHVG), the specification parameter selection and potential usage of fast controllable state-solid switches have an important bearing on the optimal design. The NPHVG with closed transformer core and fast switching thyristor (FST) was studied in this paper. According to the analysis of T-type circuit, the expressions for the voltages and currents of the primary and secondary windings on the transformer core of NPHVG were deduced, and the theoretical maximum analysis was performed. For NPHVG, the rise-rate of turn-on current (di/dt) across a FST may exceed its transient rating. Both mean and maximum values of di/dt were determined by the leakage inductances of the transformer, and the difference is 1.57 times. The optimum winding ratio is helpful to getting higher voltage output with lower specification FST, especially when the primary and secondary capacitances have been established. The oscillation period analysis can be effectively used to estimate the equivalent leakage inductance. When the core saturation effect was considered, the maximum di/dt estimated from the oscillating period of the primary current is more accurate than one from the oscillating period of the secondary voltage. Although increasing the leakage inductance of NPHVG can decrease di/dt across FST, it may reduce the output peak voltage of the NPHVG.

  3. Influence of Applied Bias Voltage on the Composition, Structure, and Properties of Ti:Si-Codoped a-C:H Films Prepared by Magnetron Sputtering

    Directory of Open Access Journals (Sweden)

    Jinlong Jiang

    2014-01-01

    Full Text Available The titanium- and silicon-codoped a-C:H films were prepared at different applied bias voltage by magnetron sputtering TiSi target in argon and methane mixture atmosphere. The influence of the applied bias voltage on the composition, surface morphology, structure, and mechanical properties of the films was investigated by XPS, AFM, Raman, FTIR spectroscopy, and nanoindenter. The tribological properties of the films were characterized on an UMT-2MT tribometer. The results demonstrated that the film became smoother and denser with increasing the applied bias voltage up to −200 V, whereas surface roughness increased due to the enhancement of ion bombardment as the applied bias voltage further increased. The sp3 carbon fraction in the films monotonously decreased with increasing the applied bias voltage. The film exhibited moderate hardness and the superior tribological properties at the applied bias voltage of −100 V. The tribological behaviors are correlated to the H/E or H3/E2 ratio of the films.

  4. Low voltage integrated optics electro-optical modulator applied to optical voltage transformer based on WLI technique

    Science.gov (United States)

    Santos, J. C.; Rubini, J.; Silva, L. P. C.; Caetano, R. E.

    2015-09-01

    The use of two electro-optical modulators linked in series, one for sensing and one for recovering signals, was formerly presented by some of the authors as a solution for interrogation of optical fiber sensor systems based on WLI method. A key feature required from such systems is that half-wave voltage (Vπ) of recovering modulator must be as small as possible. Aiming at meeting this requirement, in this paper it is presented the use of an unbalanced Michelson Interferometer implemented using an integrated optics component as recover interferometer in an optical voltage transformer intended for high voltage measurements.

  5. Towards an understanding of nonlinear electrokinetics at large applied voltages in concentrated solutions

    CERN Document Server

    Bazant, Martin Z; Storey, Brian D; Ajdari, Armand

    2009-01-01

    The venerable theory of electrokinetic phenomena rests on the hypothesis of a dilute solution of point-like ions in quasi-equilibrium with a weakly charged surface, whose potential relative to the bulk is of order the thermal voltage ($kT/e \\approx 25$ mV at room temperature). In nonlinear electrokinetic phenomena, such as AC or induced-charge electro-osmosis (ACEO, ICEO) and induced-charge electrophoresis (ICEP), several Volts $\\approx 100 kT/e$ are applied to polarizable surfaces in microscopic geometries, and the classical theory breaks down. In this article, we review the experimental and theoretical literatures, highlight discrepancies between theory and experiment, introduce possible modifications of the theory, and analyze their consequences. We argue that, in response to a large applied voltage, the ``compact layer'' and ``shear plane'' effectively advance into the liquid, due to the crowding of solvated counter-ions. Using simple continuum models, we predict two general trends at large voltages: (i) ...

  6. Negative Bias Temperature Instability "Recovery" under Negative Stress Voltage with Different Oxide Thicknesses

    Institute of Scientific and Technical Information of China (English)

    CAO Yan-Rong; MA Xiao-Hua; HAO Yue; ZHU Min-Bo; TIAN Wen-Chao; ZHANG Yue

    2011-01-01

    Different phenomena are observed under negative gate voltage stress which is smaller than the previous degradation stress in PMOSFETs with different oxide thicknesses. We adopt the real time method to make a point of the drain current to study the degradation and recovery of negative bias temperature instability (NBTI). For the device with thin oxide, recovery phenomenon appears when smaller negative voltage stress was applied, due to the more influencing oxide charges detrapping effects than the interface states. For the device with thick oxide, not recovery but degradation phenomenon comes forth. As many charges are trapped in the deeper position and higher energy level in the oxide, these charges can not be detrapped. Therefore, the effect of the charge detrapping is smaller than that of the interface states in the thick oxide. The degradation presents itself during the 'recovery' time.

  7. Effect of applied voltage on surface properties of anodised titanium in mixture of β-glycerophosphate (β-GP) and calcium acetate (CA)

    Energy Technology Data Exchange (ETDEWEB)

    Chuan, Lee Te, E-mail: gd130079@siswa.uthm.edu.my; Rathi, Muhammad Fareez Mohamad, E-mail: cd110238@siswa.uthm.edu.my; Abidin, Muhamad Yusuf Zainal, E-mail: cd110221@siswa.uthm.edu.my; Abdullah, Hasan Zuhudi, E-mail: hasan@uthm.edu.my; Idris, Maizlinda Izwana, E-mail: izwana@uthm.edu.my [Faculty of Mechanical and Manufacturing Engineering, Universiti Tun Hussein Onn Malaysia, 86400 Parit Raja, Batu Pahat, Johor (Malaysia)

    2015-07-22

    Anodic oxidation is a surface modification method which combines electric field driven metal and oxygen ion diffusion for formation of oxide layer on the anode surface. This method has been widely used to modify the surface morphology of biomaterial especially titanium. This study aimed to investigate the effect of applied voltage on titanium. Specifically, the titanium foil was anodised in mixture of β-glycerophosphate disodium salt pentahydrate (β-GP) and calcium acetate monohydrate (CA) with different applied voltage (50-350 V), electrolyte concentration (0.04 M β-GP + 0.4 M CA), anodising time (10minutes) and current density (50 and 70 mA.cm{sup −2}) at room temperature. Surface oxide properties of anodised titanium were characterised by digital single-lens reflex camera (DSLR camera), field emission scanning electron microscope (FESEM) and atomic force microscopy (AFM). At lower applied voltage (≤150 V), surface of titanium foils were relatively smooth. With increasing applied voltage (≥250 V), the oxide layer became more porous and donut-shaped pores were formed on the surface of titanium foils. The AFM results indicated that the surface roughness of anodised titanium increases with increasing of applied voltage. The porous and rough surface is able to promote the osseointegration and reduce the suffering time of patient.

  8. Steric effects in the dynamics of electrolytes at large applied voltages: I. Double-layer charging

    CERN Document Server

    Kilic, M S; Ajdari, A; Kilic, Mustafa Sabri; Bazant, Martin Z.; Ajdari, Armand

    2006-01-01

    The classical Poisson-Boltzmann (PB) theory of electrolytes assumes a dilute solution of point charges with mean-field electrostatic forces. Even for very dilute solutions, however, it predicts absurdly large ion concentrations (exceeding close packing) for surface potentials of only a few tenths of a volt, which are often exceeded, e.g. in microfluidic pumps and electrochemical sensors. Since the 1950s, several modifications of the PB equation have been proposed to account for the finite size of ions in equilibrium, but in this two-part series, we consider steric effects on diffuse charge dynamics (in the absence of electro-osmotic flow). In this first part, we review the literature and analyze two simple models for the charging of a thin double layer, which must form a condensed layer of close-packed ions near the surface at high voltage. A surprising prediction is that the differential capacitance typically varies non-monotonically with the applied voltage, and thus so does the response time of an electrol...

  9. Effects of the difference in tube voltage of the CT scanner on dose calculation

    CERN Document Server

    Rhee, Dong Joo; Moon, Young Min; Kim, Jung Ki; Jeong, Dong Hyeok

    2015-01-01

    Computed Tomography (CT) measures the attenuation coefficient of an object and converts the value assigned to each voxel into a CT number. In radiation therapy, CT number, which is directly proportional to the linear attenuation coefficient, is required to be converted to electron density for radiation dose calculation for cancer treatment. However, if various tube voltages were applied to take the patient CT image without applying the specific CT number to electron density conversion curve, the accuracy of dose calculation would be unassured. In this study, changes in CT numbers for different materials due to change in tube voltage were demonstrated and the dose calculation errors in percentage depth dose (PDD) and a clinical case were analyzed. The maximum dose difference in PDD from TPS dose calculation and Monte Carlo simulation were 1.3 % and 1.1 % respectively when applying the same CT number to electron density conversion curve to the 80 kVp and 140 kVp images. In the clinical case, the different CT nu...

  10. Hydrodynamic flow in the vicinity of a nanopore induced by an applied voltage

    CERN Document Server

    Mao, Mao; Hu, Guohui

    2013-01-01

    Continuum simulation is employed to study ion transport and fluid flow through a nanopore in a solid-state membrane under an applied potential drop. Results show the existence of concentration polarization layers on the surfaces of the membrane. The nonuniformity of the ionic distribution gives rise to an electric pressure that drives vortical motion in the fluid. There is also a net hydrodynamic flow through the nanopore due to an asymmetry induced by the membrane surface charge. The qualitative behavior is similar to that observed in a previous study using molecular dynamic simulations. The current--voltage characteristics show some nonlinear features but are not greatly affected by the hydrodynamic flow in the parameter regime studied. In the limit of thin Debye layers, the electric resistance of the system can be characterized using an equivalent circuit with lumped parameters. Generation of vorticity can be understood qualitatively from elementary considerations of the Maxwell stresses. However, the flow...

  11. Performance Evaluation of Three Different Inverter Configurations of DVR for Mitigation of Voltage Events

    Directory of Open Access Journals (Sweden)

    Miska Prasad

    2016-12-01

    Full Text Available The voltage events namely voltage sags and voltage swells represent the most common, frequent and important power quality events in today’s power system. Dynamic voltage restorer (DVR is one of the key components used to mitigate the supply voltage quality disturbances in terms of voltage sags and swells in the distribution system. It consists of an energy storage unit, a voltage source inverter, a filter, a coupling transformer and the control system. This paper presents three different inverter configurations of dynamic voltage restorer (DVR for mitigation of voltage events such as voltage sags and swells with sudden addition or removal of the nonlinear load. These three configurations are voltage source inverter based DVR (VSI-DVR, current source inverter based DVR (CSI-DVR and impedance or Z-source inverter based DVR (ZSI-DVR. The d-q control technique is used to control the operation of the DVR. The response of ZSI-DVR for mitigation of voltage sags and swells are investigated and compared with VSI-DVR and CSI-DVR using MATLAB/SIMULINK environment.

  12. Study on the influence of applied voltage and feed concentration on the performance of electrodeionization

    Directory of Open Access Journals (Sweden)

    Yohanes Ervan1

    2002-11-01

    Full Text Available Electrodeionization (EDI, a membrane process for removing ion from aqueous feed, becomes more popular nowadays. Its ability to produce ultrapure water gives significant contributions to chemical and semiconductor industries. Only few researches have been published to evaluate its performance in producing ultrapure water, especially in studying and analysing the relation between process parameter and its performance. This work is intended to observe and evaluate the influence of voltage applied and feed concentration on EDI performance. The raw material used in experiment is tap water filtered by reverse osmosis unit before proceeding to the electrodeionization. Product analysis, the diluate as well as the concentrate, is carried out by using conductivity meter and pH meter. The experimental results are presented in i vs V curve, product conductivity vs time, and product pH vs time. From experimental results, it is concluded that concentration polarization can be minimized in EDI process, the increasing of applied current increases product pH. However, there is a limit in gradient concentration between feed and concentrate to minimize the occurence of counter diffusion phenomena.

  13. Characterization of Multicrystalline Silicon Modules with System Bias Voltage Applied in Damp Heat

    Energy Technology Data Exchange (ETDEWEB)

    Hacke, P.; Kempe, M.; Terwilliger, K.; Glick, S.; Call, N.; Johnston, S.; Kurtz, S.

    2011-07-01

    As it is considered economically favorable to serially connect modules to build arrays with high system voltage, it is necessary to explore potential long-term degradation mechanisms the modules may incur under such electrical potential. We performed accelerated lifetime testing of multicrystalline silicon PV modules in 85 degrees C/ 85% relative humidity and 45 degrees C/ 30% relative humidity while placing the active layer in either positive or negative 600 V bias with respect to the grounded module frame. Negative bias applied to the active layer in some cases leads to more rapid and catastrophic module power degradation. This is associated with significant shunting of individual cells as indicated by electroluminescence, thermal imaging, and I-V curves. Mass spectroscopy results support ion migration as one of the causes. Electrolytic corrosion is seen occurring with the silicon nitride antireflective coating and silver gridlines, and there is ionic transport of metallization at the encapsulant interface observed with damp heat and applied bias. Leakage current and module degradation is found to be highly dependent upon the module construction, with factors such as encapsulant and front glass resistivity affecting performance. Measured leakage currents range from about the same seen in published reports of modules deployed in Florida (USA) and is accelerated to up to 100 times higher in the environmental chamber testing.

  14. Five-Level Converter with Low Switching Frequency Applied as DC Voltage Supply

    DEFF Research Database (Denmark)

    Rasmussen, Tonny Wederberg

    1999-01-01

    This paper describes the use of a multi-level converter as a DC supply. Equations for the converter will be deduced in the nondissipative case. The equations provide solutions to DC voltage and the angle of converter voltage. In addition the spectrum for the harmonics after the elimination...

  15. High voltage generator circuit with low power and high efficiency applied in EEPROM

    Institute of Scientific and Technical Information of China (English)

    Liu Yan; Zhang Shilin; Zhao Yiqiang

    2012-01-01

    This paper presents a low power and high efficiency high voltage generator circuit embedded in electrically erasable programmable read-only memory (EEPROM).The low power is minimized by a capacitance divider circuit and a regulator circuit using the controlling clock switch technique.The high efficiency is dependent on the zero threshold voltage (Vth) MOSFET and the charge transfer switch (CTS) charge pump.The proposed high voltage generator circuit has been implemented in a 0.35μm EEPROM CMOS process.Measured results show that the proposed high voltage generator circuit has a low power consumption of about 150.48 μW and a higher pumping efficiency (83.3%) than previously reported circuits.This high voltage generator circuit can also be widely used in low-power flash devices due to its high efficiency and low power dissipation.

  16. Investigation on the energy spectrums of electrons in atmospheric pressure argon plasma jets and their dependences on the applied voltage

    Science.gov (United States)

    Chen, Xinxian; Tan, Zhenyu; Liu, Yadi; Li, Xiaotong; Pan, Jie; Wang, Xiaolong

    2017-08-01

    This work presents a systematical investigation on the spatiotemporal evolution of the energy spectrum of electrons in atmospheric pressure argon plasma jets and its dependence on the applied voltage. The investigations are carried out by means of the numerical simulation based on a particle-in-cell Monte-Carlo collision model. The characteristics of the spatiotemporal evolution of the energy spectrum of electrons (ESE) in the discharge space have been presented, and especially the mechanisms of inducing these characteristics have also been revealed. The present work shows the following conclusions. In the evolution of ESE, there is a characteristic time under each applied voltage. Before the characteristic time, the peak value of ESE decreases, the peak position shifts toward high energy, and the distribution of ESE becomes wider and wider, but the reverse is true after the characteristic time. The formation of these characteristics can be mainly attributed to the transport of electrons toward a low electric field as well as a balance between the energy gained from the electric field including the effect of space charges and the energy loss due to inelastic collisions in the process of electron transport. The characteristic time decreases with the applied voltage. In addition, the average energy of electrons at the characteristic time can be increased by enhancing the applied voltage. The results presented in this work are of importance for regulating and controlling the energy of electrons in the plasma jets applied to plasma medicine.

  17. Transient demonstration of exciton behaviours in solid state cathodoluminescence under different driving voltage

    Institute of Scientific and Technical Information of China (English)

    Zhang Fu-Jun; Zhao Su-Ling; Xu Zheng; Huang Jin-Zhao; Xu Xu-Rong

    2007-01-01

    In the solid state cathodoluminescence (SSCL), organic materials were excited by hot electrons accelerated in silicon oxide (SiO2) layer under alternating current (AC). In this paper exciton behaviours were analysed by using transient spectra under different driving voltages. The threshold voltages of SSCL and exciton ionization were obtained from the transient spectra. The recombination radiation occurred when the driving voltage went beyond the threshold voltage of exciton ionization. Prom the transient spectrum of two kinds of luminescence (exciton emission and recombination radiation), it was demonstrated that recombination radiation should benefit from the exciton ionization.

  18. DIFFUSE DBD IN ATMOSPHERIC AIR AT DIFFERENT APPLIED PULSE WIDTHS

    Directory of Open Access Journals (Sweden)

    Ekaterina Alexandrovna Shershunova

    2015-02-01

    Full Text Available The paper deals with the realization and the diagnostics of the volume diffuse dielectric barrier discharge in 1-mm air gap when applying high voltage rectangular pulses to the electrodes. The effect of the applied pulse width on the discharge dissipated energy was studied in detail. It was found experimentally, the energy stayed nearly constant with the pulse elongation from 600 ns to 1 ms.

  19. Technical Conditions of Microgenerator Connection to a Low Voltage Network Taking Into Account Valid Rules and Practices Applied in Europe and Poland

    Directory of Open Access Journals (Sweden)

    Marian Sobierajski

    2014-12-01

    Full Text Available Connection of microgenerators to a low voltage network affects the electrical energy quality. In the paper, the basic relationships have been set out to compute voltage deviations and fluctuations. The basic criteria of microgeneration connection to a low voltage network have been given. The valid rules and practices applied in Europe and Poland have been described.

  20. Investigation of Harmonic Characteristics in Printer due to Different Types of Voltage Source

    Directory of Open Access Journals (Sweden)

    C. Risnidar

    2012-01-01

    Full Text Available This paper discusses about harmonic characteristics due to different types of voltage sources. Usually, the voltage source is sinusoidal. But in actual condition the load that receives voltage sources through the elements where the output voltage of element as input to the load is not pure sinusoidal, for example voltage source at Power of Common Coupling (PCC between transformer and linear load and nonlinear load. This research has been done  with Schhafner Power Quality Analyzer and PM300 Power Quality Analyzer, was focused to all harmonic characteristics as power, voltage, current, power factor (p.f., Harmonic Distortion, and harmonic energy losses cost. The load is printer because the printer is one of electronic device causes harmonics. The voltage sources in this research are sine wave, triangle wave and harmonic order combinations of 3rd, 5th and 9th. Why this research discuses voltage source for Harmonic order 3rd, 5th and 9th and don not combination of 3rd, 5th and 7th, because the combination 3rd, 5th and 9th is more complicated then combination of 3rd, 5th and 7th.

  1. Voltage-controlled magnetization switching in MRAMs in conjunction with spin-transfer torque and applied magnetic field

    Science.gov (United States)

    Munira, Kamaram; Pandey, Sumeet C.; Kula, Witold; Sandhu, Gurtej S.

    2016-11-01

    Voltage-controlled magnetic anisotropy (VCMA) effect has attracted a significant amount of attention in recent years because of its low cell power consumption during the anisotropy modulation of a thin ferromagnetic film. However, the applied voltage or electric field alone is not enough to completely and reliably reverse the magnetization of the free layer of a magnetic random access memory (MRAM) cell from anti-parallel to parallel configuration or vice versa. An additional symmetry-breaking mechanism needs to be employed to ensure the deterministic writing process. Combinations of voltage-controlled magnetic anisotropy together with spin-transfer torque (STT) and with an applied magnetic field (Happ) were evaluated for switching reliability, time taken to switch with low error rate, and energy consumption during the switching process. In order to get a low write error rate in the MRAM cell with VCMA switching mechanism, a spin-transfer torque current or an applied magnetic field comparable to the critical current and field of the free layer is necessary. In the hybrid processes, the VCMA effect lowers the duration during which the higher power hungry secondary mechanism is in place. Therefore, the total energy consumed during the hybrid writing processes, VCMA + STT or VCMA + Happ, is less than the energy consumed during pure spin-transfer torque or applied magnetic field switching.

  2. Design and Fabrication of Micromechanical Optical Switches Based on the Low Applied Voltage

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    A micromechanical optical switch driven by electrostatic was fabricated with (100) silicon and tilted 2.5° (111) silicon. The pull-in voltage is 13.2V, the insertion loss is less than 1.4dB, the crosstalk is less than -50 dB.

  3. Threshold Voltage of MOSFET Devices Extracted by Normalized Mutual Integral Difference Operator

    Institute of Scientific and Technical Information of China (English)

    HEJin; ZHENGTaolei; ZHANGXing; WANGYangyuan

    2003-01-01

    The threshold voltage of MOSFETs to be extracted by a novel experimental method named the nor-realized mutual integral difference operator has been inves-tigated in this paper. The basic principle of this method is to use the extreme spectral characteristics of the nor-realized mutual integral difference result of the MOSFET transfer characteristics to find the threshold voltage. Ap-plication of this method has also been demonstrated nu-merically in extracting the threshold voltage of MOS de-vices with the different effective channel length and par-asitic series resistance. The results show this method is sensitive to the channel length variation while insensitive to the parasitic resistance component. The extracted re-sults on the threshold voltage of MOSFET devices have been compared with those obtained by the second deriva-tive method and the agreements have been found, showing the advantage of the method presented here.

  4. Nicotiana Occidentalis Chloroplast Ultrastructure imaged with Transmission Electron Microscopes Working at Different Accelerating Voltages

    OpenAIRE

    SVIDENSKÁ, Silvie

    2010-01-01

    The main goal of this thesis is to study and compare electron microscopy images of Nicotiana Occidentalis chloroplasts, obtained from two types of transmission electron microscopes,which work with different accelerating voltage of 80kV and 5kV. The two instruments, TEM JEOL 1010 and low voltage electron microscope LVEM5 are employed for experiments. In the first theoretical part, principle of electron microscopy and chloroplast morphology is described. In experimental part, electron microscop...

  5. Optical fiber imaging for high speed plasma motion diagnostics: applied to low voltage circuit breakers.

    Science.gov (United States)

    McBride, J W; Balestrero, A; Ghezzi, L; Tribulato, G; Cross, K J

    2010-05-01

    An integrated portable measurement system is described for the study of high speed and high temperature unsteady plasma flows such as those found in the vicinity of high current switching arcs. An array of optical fibers allows the formation of low spatial resolution images, with a maximum capture rate of 1 x 10(6) images per second (1 MHz), with 8 bit intensity resolution. Novel software techniques are reported to allow imaging of the arc; and to measure arc trajectories. Results are presented on high current (2 kA) discharge events in a model test fixture and on the application to a commercial low voltage circuit breaker.

  6. Performance of a semi-pilot tubular microbial electrolysis cell (MEC) under several hydraulic retention times and applied voltages.

    Science.gov (United States)

    Gil-Carrera, L; Escapa, A; Carracedo, B; Morán, A; Gómez, X

    2013-10-01

    The influence of applied voltage and hydraulic retention time on the performance of a semi-pilot modular tubular wastewater-fed microbial electrolysis cell (MEC) with high scalability was investigated. A chemical oxygen demand (COD) removal efficiency of 80%, as well as an energy consumption of 0.3-1.1 Wh g-COD(-1) removed, were achieved. Hydrogen production was limited by the reduced amounts of organic matter fed into the reactor, the poor performance of the cathode, and COD consuming by non electrogenic microorganisms. The presence of COD consuming microorganism that do not contribute to electrogenic metabolism severely affected the MEC performance.

  7. Distance protection of multiple-circuit shared tower transmission lines with different voltages. Part I: Fault current magnitude

    DEFF Research Database (Denmark)

    Silva, Filipe Miguel Faria da; Bak, Claus Leth

    2017-01-01

    Multiple-circuit transmission lines combining different voltage levels in one tower present extra challenges when setting a protection philosophy, as faults between voltage levels are possible. This paper presents a detailed theoretical analysis of such combined faults, including the development...... of a formula for estimating the magnitude of the short-circuit current. It is demonstrated that if the faulted phase from the higher voltage level leads the faulted phase from the lower voltage level, a distance relay at the higher voltage level sees the fault in the forward direction, whereas a distance relay...... at the lower voltage level sees the fault in the reverse direction. The opposite happens if the lower voltage level leads the higher voltage level. It is also demonstrated that the magnitude of fault currents of combined faults is normally slightly larger than of equivalent single-phase-to-ground fault...

  8. Voltage-Mode Multifunction Biquadratic Filters Using New Ultra-Low-Power Differential Difference Current Conveyors

    Directory of Open Access Journals (Sweden)

    M. Kumngern

    2013-06-01

    Full Text Available This paper presents two low-power voltage-mode multifunction biquadratic filters using differential difference current conveyors. Each proposed circuit employs three differential difference current conveyors, two grounded capacitors and two grounded resistors. The low-voltage ultra-low-power differential difference current conveyor is used to provide low-power consumption of the proposed filters. By appropriately connecting the input and output terminals, the proposed filters can provide low-pass, band-pass, high-pass, band-stop and all-pass voltage responses at high-input terminals, which is a desirable feature for voltage-mode operations. The natural frequency and the quality factor can be orthogonally set by adjusting the circuit components. For realizing all the filter responses, no inverting-type input signal requirements as well as no component-matching conditional requirements are imposed. The incremental parameter sensitivities are also low. The characteristics of the proposed circuits are simulated by using PSPICE simulators to confirm the presented theory.

  9. Optical and Electrical Performance of MOS-Structure Silicon Solar Cells with Antireflective Transparent ITO and Plasmonic Indium Nanoparticles under Applied Bias Voltage

    Directory of Open Access Journals (Sweden)

    Wen-Jeng Ho

    2016-08-01

    Full Text Available This paper reports impressive improvements in the optical and electrical performance of metal-oxide-semiconductor (MOS-structure silicon solar cells through the incorporation of plasmonic indium nanoparticles (In-NPs and an indium-tin-oxide (ITO electrode with periodic holes (perforations under applied bias voltage. Samples were prepared using a plain ITO electrode or perforated ITO electrode with and without In-NPs. The samples were characterized according to optical reflectance, dark current voltage, induced capacitance voltage, external quantum efficiency, and photovoltaic current voltage. Our results indicate that induced capacitance voltage and photovoltaic current voltage both depend on bias voltage, regardless of the type of ITO electrode. Under a bias voltage of 4.0 V, MOS cells with perforated ITO and plain ITO, respectively, presented conversion efficiencies of 17.53% and 15.80%. Under a bias voltage of 4.0 V, the inclusion of In-NPs increased the efficiency of cells with perforated ITO and plain ITO to 17.80% and 16.87%, respectively.

  10. Optical and Electrical Performance of MOS-Structure Silicon Solar Cells with Antireflective Transparent ITO and Plasmonic Indium Nanoparticles under Applied Bias Voltage.

    Science.gov (United States)

    Ho, Wen-Jeng; Sue, Ruei-Siang; Lin, Jian-Cheng; Syu, Hong-Jang; Lin, Ching-Fuh

    2016-08-10

    This paper reports impressive improvements in the optical and electrical performance of metal-oxide-semiconductor (MOS)-structure silicon solar cells through the incorporation of plasmonic indium nanoparticles (In-NPs) and an indium-tin-oxide (ITO) electrode with periodic holes (perforations) under applied bias voltage. Samples were prepared using a plain ITO electrode or perforated ITO electrode with and without In-NPs. The samples were characterized according to optical reflectance, dark current voltage, induced capacitance voltage, external quantum efficiency, and photovoltaic current voltage. Our results indicate that induced capacitance voltage and photovoltaic current voltage both depend on bias voltage, regardless of the type of ITO electrode. Under a bias voltage of 4.0 V, MOS cells with perforated ITO and plain ITO, respectively, presented conversion efficiencies of 17.53% and 15.80%. Under a bias voltage of 4.0 V, the inclusion of In-NPs increased the efficiency of cells with perforated ITO and plain ITO to 17.80% and 16.87%, respectively.

  11. A microbial fuel cell with the three-dimensional electrode applied an external voltage for synthesis of hydrogen peroxide from organic matter

    Science.gov (United States)

    Chen, Jia-yi; Zhao, Lin; Li, Nan; Liu, Hang

    2015-08-01

    The study experimentally investigates the changing performance of three-dimensional electrode H2O2-producting MFCs coupled with simultaneous wastewater treatment at various external cell voltages from 0.1 V to 0.8 V, in order to explore the optimal applied voltage and its reasons. The graphite particle electrodes made of graphite powders with polytetrafluoroethene (PTFE) as the binder are used as three-dimensional cathode. The results indicate that applied voltage is demonstrated to increase the productive rate and output of H2O2 and the efficiency of acetate degradation. Besides, a relatively high current density caused by a high applied voltage has a positive impact on anode performance in terms of organic degradation and coulombic efficiency. In addition, a relatively high voltage leads to the reduction of H2O2 and the evolution of H2. Considering H2O2 concentration, anodic COD removal and current efficiencies of MFCs at various voltages, the optimal voltage is chosen to be 0.4 V, achieving the H2O2 generation of 705.6 mg L-1 at a rate of 2.12 kg m-3 day-1 and 76% COD removal in 8 h, with energy input of 0.659 kWh per kg H2O2. Coulombic efficiency, faradic efficiency and COD conversion efficiency are 92%, 96%, and 88% respectively.

  12. Design and simulation of the space vector modulation and applied to a load RL powered by a voltage inverter

    Directory of Open Access Journals (Sweden)

    Marouane El Azzaoui

    2016-07-01

    Full Text Available The vector control performance applied to rotating machines depends largely on static and dynamic characteristics of the inverter associated with it. The development of the pulse-width modulation (PWM provided greater flexibility in the control of the converters. The objective of this work is to construct a simplified and practical space vector modulation (SVM based on the selection of the sequence and the calculation of the conduction time or extinction. We have presented the blocks of the simulation vector modulation on the Matlab / Simulink with a new method for determining conduction time and analyzed its application on a load RL supplied by a voltage inverter. The performance of the proposed method has been presented by the simulation results.

  13. A comparative study of the action of tolperisone on seven different voltage dependent sodium channel isoforms.

    Science.gov (United States)

    Hofer, Doris; Lohberger, Birgit; Steinecker, Bibiane; Schmidt, Kurt; Quasthoff, Stefan; Schreibmayer, Wolfgang

    2006-05-24

    The specific, acute interaction of tolperisone, an agent used as a muscle relaxant and for the treatment of chronic pain conditions, with the Na(v1.2), Na(v1.3), Na(v1.4), Na(v1.5), Na(v1.6), Na(v1.7), and Na(v1.8) isoforms of voltage dependent sodium channels was investigated and compared to that of lidocaine. Voltage dependent sodium channels were expressed in the Xenopus laevis oocyte expression system and sodium currents were recorded with the two electrode voltage clamp technique. Cumulative dose response relations revealed marked differences in IC(50) values between the two drugs on identical isoforms, as well as between isoforms. A detailed kinetic analysis uncovered that tolperisone as well as lidocaine exhibited their blocking action not only via state dependent association/dissociation with voltage dependent sodium channels, but a considerable fraction of inhibition is tonic, i.e. permanent and basic in nature. Voltage dependent activation was affected to a minor extent only. A shift in steady-state inactivation to more negative potentials could be observed for most drug/isoform combinations. The contribution of this shift to overall block was, however, small at drug concentrations resulting in considerable overall block. Recovery from inactivation was affected notably by both drugs. Lidocaine application led to a pronounced prolongation of the time constant of the fast recovery process for the Na(v1.3), Na(v1.5), and Na(v1.7) isoforms, indicating common structural properties in the local anesthetic receptor site of these three proteins. Interestingly, this characteristic drug action was not observed for tolperisone.

  14. EFFECT OF DIFFERENT VOLTAGE AND FREQUENCY CONDITIONS IN BROILERS ELECRICAL STUNNING

    Directory of Open Access Journals (Sweden)

    A. Vecchini

    2008-12-01

    Full Text Available The effectiveness of broiler stunning using different voltage and current frequency and the consequences on meat quality are reported. Loss of sensitivity was controlled in fifteen batches of medium and heavy broilers (i.e. corneal reflex, time for recover tension of neck muscles, quick beat of wings, head movements and frequency of these signs was related to the theoretical (calculated current that passed through the bird bodies. Prevalence of defects like pectoral muscles haemorrhages and coracoid’s or furculum’s fractures are not higher when frequency of current was reduced from 350 to 250 Hz and voltage maintained at 70-75 Volts, but the frequency of birds showing corneal reflex change from 91 to 33 percent and time for recover tension of neck muscles significantly increase. Any sign of reduced bleeding was observed and meat quality was similar in batches stunned at 250 and 350 Hz.

  15. Study of CT head scans using different voltages: image quality evaluation

    Energy Technology Data Exchange (ETDEWEB)

    Pacheco de Freitas C, I.; Prata M, A. [Centro Federal de Educacao Tecnologica de Minas Gerais, Centro de Engenharia Biomedica, Av. Amazonas 5253, 30421-169 Nova Suica, Belo Horizonte, Minas Gerais (Brazil); Alonso, T. C. [Centro de Desenvolvimento da Tecnologia Nuclear / CNEN, Av. Pte. Antonio Carlos 6627, 31270-901 Pampulha, Belo Horizonte, Minas Gerais (Brazil); Santana, P., E-mail: iarapfcorrea@gmail.com [Universidade Federal de Minas Gerais, Departamento de Anatomia e Imagem, Av. Prof. Alfredo Balena 190, 30130-100 Belo Horizonte, Minas Gerais (Brazil)

    2016-10-15

    Computed tomography (CT) was introduced to medical practice in 1972. It generates images recognized by high diagnostic potential. CT allows investigation of structures in the human body inaccessible by conventional image methods, replacing invasive methods in many cases. Noise is a kind of variation of brightness observed on CT images, and it is inherent to this method. The magnitude of the noise is determined by the standard deviation of CT numbers of a region of interest in a homogeneous material. The aim of this study is to analyze the noise in head CT images generated by different acquisition protocols using four voltage values. Five different scans were performed using a female Alderson phantom and their images were analyzed with the RadiAnt software. With the average HU values and standard deviation of each scan, the values of noise were calculated in some region of interest. The obtained noise values were compared and it was observed that the 140 kV voltage promotes the in the lower noise in the image, resulting in better image quality. The results also show that the parameters, such as voltage and current, can be adjusted so that the noise can be decreased. Thus, acquisition protocols may be adapted to produce images with diagnostic quality and lower doses in patient. (Author)

  16. Comparative Studies of Different Control Strategies of a Dynamic Voltage Restorer Based on Matrix Converter

    Directory of Open Access Journals (Sweden)

    Amin Shabanpour

    2012-01-01

    Full Text Available A dynamic voltage restorer (DVR with no energy storage is studied. By using a matrix converter instead of the conventional AC/DC/AC converters, elimination of the DC-link capacitor is possible. The switching algorithm of matrix converter is the space vector modulation. There are different compensation algorithms to control the conventional DVR. These methods have been analyzed in this paper for the proposed matrix-converter-based DVR. A deep analysis through different diagrams would show the advantages or disadvantages of each compensation method. Equations for all methods are derived, and the characteristics of algorithms are compared with each other.

  17. Characterization of different surface passivation routes applied to a planar HPGe detector

    Energy Technology Data Exchange (ETDEWEB)

    Maggioni, G.; Gelain, M.; Carturan, S. [University of Padova, Department of Physics and Astronomy ' ' G. Galilei' ' , Padova (Italy); Laboratori Nazionali di Legnaro, Istituto Nazionale di Fisica Nucleare, Legnaro (Italy); Napoli, D.R. [Laboratori Nazionali di Legnaro, Istituto Nazionale di Fisica Nucleare, Legnaro (Italy); Eberth, J. [Universitaet zu Koeln, Institut fuer Kernphysik, Koeln (Germany); Grimaldi, M.G.; Tati, S. [University of Catania, Department of Physics and Astronomy, Catania (Italy)

    2015-11-15

    The effects of different passivation methods applied to the same planar high-purity germanium gamma radiation detector have been studied. By means of the scanning with a low-energy collimated gamma source, it has been found that the surface passivation gives rise to a dead layer below the intrinsic Ge surface, whose thickness and distribution are strongly dependent on the passivation type. Measured bulk detector properties like the peak-to-Compton ratio and efficiency have shown a dependence on the passivation and an influence of the passivation type on the depletion voltage, whilst the optimal energy resolution has been the same for all the passivations. (orig.)

  18. Modeling of the Partial Discharge Process in a Liquid Dielectric: Effect of Applied Voltage, Gap Distance, and Electrode Type

    Directory of Open Access Journals (Sweden)

    Tao Yuan

    2013-02-01

    Full Text Available The partial discharge (PD process in liquid dielectrics is influenced by several factors. Although the PD current contains the information representing the discharge process during the PD event, it is difficult to determine the detailed dynamics of what is happening in the bulk of the liquid. In this paper, a microscopic model describing the dynamics of the charge carriers is implemented. The model consists of drift-diffusion equations of electrons, positive and negative ions coupled with Poisson’s equation. The stochastic feature of PD events is included in the equation. First the model is validated through comparison between the calculated PD current and experimental data. Then experiments are conducted to study the effects of the amplitude of the applied voltage, gap distance and electrode type on the PD process. The PD currents under each condition are recorded. Simulations based on the model have been conducted to analyze the dynamics of the PD events under each condition, and thus explain the mechanism of how these factors influence the PD events. The space charge generated in the PD process is revealed as the main reason affecting the microscopic process of the PD events.

  19. Distance protection of multiple-circuit shared tower transmission lines with different voltages. Part II: Fault loop impedance

    DEFF Research Database (Denmark)

    Silva, Filipe Miguel Faria da; Bak, Claus Leth

    2017-01-01

    Multiple-circuit transmission lines combining different voltage levels in one tower present extra challenges when setting a protection philosophy, as faults between voltage levels are possible. In this paper, the fault loop impedance of combined faults is compared with the fault loop impedance...... of single-phase-to-ground faults at the higher voltage level of the multiple-circuit line and it is demonstrated that they are similar for high short-circuit powers; however, the fault loop impedance of a combined fault may increase substantially as the short-circuit power of the system decreases......-phase-to-ground faults are also capable of protecting the line against combined faults, being only advisable to increase the resistive limit of the protection zone if the network has lower short-circuit power. If the length of the line at lower voltage level is less than of the lien at higher voltage level...

  20. 外部电压源法测试大电压LED器件/模块热阻%Measuring thermal resistance for high voltage LED device and module by applying ex ternal voltage source

    Institute of Scientific and Technical Information of China (English)

    陈国龙; 朱丽虹; 郭自泉; 张纪红; 吕毅军; 高玉琳; 陈忠

    2013-01-01

    热阻是衡量LED器件/模块散热性能的重要参数。针对大电压LED器件/模块,实验采用 T3Ster/T eraled热光参数测试仪,利用外部电压源供电方法,实现了对超过仪器量程的大电压L ED器件的热阻测试。该方法拓展了热阻测试仪的常规测量范围,使正向电压大于15 V的L ED器件/模块的热阻测试成为可能。%Thermal resistance is a key parameter for evaluating thermal performance of LED device/module . Reliable measurement of thermal resistance becomes extremely important .Aiming at that the high voltage LED device/module has been applied popularly in lighting ,an improved thermal resistance measurement method for LED device/module with forward voltage larger than 15V is achieved by applying external voltage source to the T3Ster/Teraled .The result shows that the external voltage source method can effectively expand the testing range of thermal resistance tester .

  1. Chemical and Morphological Characterization of Magnetron Sputtered at Different Bias Voltages Cr-Al-C Coatings

    Directory of Open Access Journals (Sweden)

    Aleksei Obrosov

    2017-02-01

    Full Text Available MAX phases (M = transition metal, A = A-group element, and X = C/N are of special interest because they possess a unique combination of the advantages of both metals and ceramics. Most attention is attracted to the ternary carbide Cr2AlC because of its excellent high-temperature oxidation, as well as hot corrosion resistance. Despite lots of publications, up to now the influence of bias voltage on the chemical bonding structure, surface morphology, and mechanical properties of the film is still not well understood. In the current study, Cr-Al-C films were deposited on silicon wafers (100 and Inconel 718 super alloy by dc magnetron sputtering with different substrate bias voltages and investigated using Scanning Electron Microscopy (SEM, X-ray Photoelectron Spectroscopy (XPS, X-ray Diffraction (XRD, Atomic Force Microscopy (AFM, and nanoindentation. Transmission Electron Microscopy (TEM was used to analyze the correlation between the growth of the films and the coating microstructure. The XPS results confirm the presence of Cr2AlC MAX phase due to a negative shift of 0.6–0.9 eV of the Al2p to pure aluminum carbide peak. The XRD results reveal the presence of Cr2AlC MAX Phase and carbide phases, as well as intermetallic AlCr2. The film thickness decreases from 8.95 to 6.98 µm with increasing bias voltage. The coatings deposited at 90 V exhibit the lowest roughness (33 nm and granular size (76 nm combined with the highest hardness (15.9 GPa. The ratio of Al carbide to carbide-like carbon state changes from 0.12 to 0.22 and correlates with the mechanical properties of the coatings. TEM confirms the columnar structure, with a nanocrystalline substructure, of the films.

  2. Transient Voltage Stability Analysis and Improvement of A Network with different HVDC Systems

    DEFF Research Database (Denmark)

    Liu, Yan; Chen, Zhe

    2011-01-01

    the theoretical analysis and the improved control method, real time simulation model of a hybrid multi-infeed HVDC system based on western Danish power system is established in RTDS™. Simulation results show that the enhanced transient voltage stability can be achieved.......This paper presents transient voltage stability analysis of an AC system with multi-infeed HVDC links including a traditional LCC HVDC link and a VSC HVDC link. It is found that the voltage supporting capability of the VSC-HVDC link is significantly influenced by the tie-line distance between...... the two links and the size of loads. In order to improve the transient voltage stability, a voltage adjusting method is proposed in this paper. A voltage increment component has been introduced into the outer voltage control loop under emergency situation caused by severe grid faults. In order to verify...

  3. Comparison between Different Control Strategies of a Z-Source Inverter Based Dynamic Voltage Restorer

    Directory of Open Access Journals (Sweden)

    Abolfazl Kazemdehdashti

    2013-01-01

    Full Text Available In this paper, dynamic voltage restorer (DVR compensation methods are compared to each other for the load side connected shunt converter topology of z-source inverter based DVR to choose the best method. Four different topologies are recognized for DVR that two of them have energy storage devices, and two topologies have no energy storage that take ener\\-gy from the grid during the period of compensation. Here the load side connected shunt converter topology that takes necessary energy from the grid is used. Pre-sag compensation, in-phase compensation, energy-optimized methods are the three DVR compensation methods that studied and compared. A deep analysis through different diagrams would show the advantages or disadvantages of each compensation method. Equations for all methods are derived and the characteristics of algorithms are compared with each other. The simulation results done by SIMULINK/ MATLAB shows compensating by this topology based on the compensation methods.

  4. The effect of applied control strategy on the current-voltage correlation of a solid oxide fuel cell stack during dynamic operation

    Directory of Open Access Journals (Sweden)

    Szmyd Janusz S.

    2014-09-01

    Full Text Available This paper discusses the transient characteristics of the planar type SOFC cell stack, of which the standard output is 300 W. The transient response of the voltage to the manipulation of an electric current was investigated. The effects of the response and of the operating condition determined by the operating temperature of the stack were studied by mapping a current-voltage (I-V correlation. The current-based fuel control (CBFC was adopted for keeping the fuel utilization factor at constant while the value of the electric current was ramped at the constant rate. The present experimental study shows that the transient characteristics of the cell voltage are determined by primarily the operating temperature caused by the manipulation of the current. Particularly, the slope of the I-V curve and the overshoot found on the voltage was remarkably influenced by the operating temperature. The different values of the fuel utilization factor influence the height of the settled voltages. The CBFC has significance in determining the slope of the I-V characteristic, but the different values ofthe fuel utilization factor does not affect the slope as the operating temperature does. The CBFC essentially does not alter the amplitude of the overshoot on the voltage response, since this is dominated by the operating temperature and its change is caused by manipulating the current.

  5. Memcapacitive characteristics in reactive-metal (Mo, Al)/HfO{sub X}/n-Si structures through migration of oxygen by applied voltage

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Paul; Noh, Young Jun; Baek, Yoon-Jae; Zheng, Hong; Yoon, Tae-Sik, E-mail: tsyoon@mju.ac.kr [Department of Materials Science and Engineering, Myongji University, Gyeonggi-do 449-728 (Korea, Republic of); Kang, Chi Jung [Department of Physics, Myongji University, Gyeonggi-do 449-728 (Korea, Republic of); Lee, Hyun Ho [Department of Chemical Engineering, Myongji University, Gyeonggi-do 449-728 (Korea, Republic of)

    2016-02-01

    Memcapacitive characteristics were investigated in metal-oxide-semiconductor (MOS) structure of reactive electrode (Mo, Al) and hafnium oxide (HfO{sub X}) on n-type Si substrate. The capacitance-voltage curves exhibited sequentially changing capacitance with memory function as repeating voltage sweeps, featured the memcapacitive behaviors. The saturation capacitance was decreased by repeating +V sweeps, while barely changed by −V sweeps. Also, the capacitance-time curves disclosed the same tendency. However, the MOS structure with inert Pt electrode did not show the capacitance change. The memcapacitive behaviors were induced by the migration of oxygen ions from HfO{sub X} to reactive electrodes by applied voltage, which altered the permittivity of HfO{sub X}.

  6. Membrane voltage differently affects mIPSCs and current responses recorded from somatic excised patches in rat hippocampal cultures.

    Science.gov (United States)

    Pytel, Maria; Mozrzymas, Jerzy W

    2006-01-30

    Recent analysis of current responses to exogenous GABA applications recorded from excised patches indicated that membrane voltage affected the GABAA receptor gating mainly by altering desensitization and binding [M. Pytel, K. Mercik, J.W. Mozrzymas, Membrane voltage modulates the GABAA receptor gating in cultured rat hippocampal neurons, Neuropharmacology, in press]. In order investigate the impact of such voltage effect on GABAA receptors in conditions of synaptic transmission, mIPSCs and current responses to rapid GABA applications were recorded from the same culture of rat hippocampal neurons. We found that I-V relationship for mIPSCs amplitudes showed a clear outward rectification while for current responses an inward rectification was seen, except for very low GABA concentrations. A clear shift in amplitude cumulative distributions indicated that outward rectification resulted from the voltage effect on the majority of mIPSCs. Moreover, the decaying phase of mIPSCs was clearly slowed down at positive voltages and this effect was represented by a shift in cumulative distributions of weighted decaying time constants. In contrast, deactivation of current responses was only slightly affected by membrane depolarization. These data indicate that the mechanisms whereby the membrane voltage modulates synaptic and extrasynaptic receptors are qualitatively different but the mechanism underlying this difference is not clear.

  7. Determination voltage applied to an X-ray tube using the spectrum; Determinacao da tensao aplicada em um tubo de raios-X usando o espectro

    Energy Technology Data Exchange (ETDEWEB)

    Albuquerque, M.A.G.; David, M.G.; Almeida, Carlos Eduardo de; Magalhaes, Luis Alexandre Goncalves, E-mail: malbuqueque@hotmail.com [Universidade do Estado do Rio de Janeiro (UERJ), Rio de Janeiro, RJ (Brazil). Lab. de Ciencias Radiologicas; Peixoto, Guilherme [Instituto de Radioprotecao e Dosimetria (IRD/CNEN-RJ), Rio de Janeiro, RJ (Brazil)

    2015-07-01

    This work shows the methodology used to determine the voltage applied in an X-ray tube using their spectra. The measurements were made using a detector Cadmium telluride . Before the measurements are carried out detector was calibrated with a source of {sup 241}Am. After obtaining the spectra , the mean energies were calculated , the electron accelerating potential (k Vp ) of each spectrum is constructed a calibration straight for the kVp this tube. (author)

  8. Graphene-coated hollow fiber membrane as the cathode in anaerobic electrochemical membrane bioreactors – Effect of configuration and applied voltage on performance and membrane fouling

    KAUST Repository

    Werner, Craig M.

    2015-12-22

    Electrically conductive, graphene-coated hollow-fiber porous membranes were used as cathodes in anaerobic electrochemical membrane bioreactors (AnEMBRs) operated at different applied voltages (0.7 V and 0.9 V) using a new rectangular reactor configuration, compared to a previous tubular design (0.7 V). The onset of biofouling was delayed and minimized in rectangular reactors operated at 0.9 V, compared to those at 0.7 V due to higher rates of hydrogen production. Maximum transmembrane pressures for the rectangular reactor were only 0.10 bar (0.7 V) or 0.05 bar (0.9 V) after 56 days of operation, compared to 0.46 bar (0.7 V) for the tubular reactor after 52 days. The thickness of the membrane biofouling layer was approximately 0.4 µm for rectangular reactors and 4 µm for the tubular reactor. Higher permeate quality (TSS = 0.05 mg/L) was achieved in the rectangular AnEMBR than the tubular AnEMBR (TSS = 17 mg/L), likely due to higher current densities that minimized the accumulation of cells in suspension. These results show that the new rectangular reactor design, which had increased rates of hydrogen production, successfully delayed the onset of cathode biofouling and improved reactor performance.

  9. 负偏压法测试大电压LED器件热阻%Measuring thermal resistance for high voltage LED device and module by applying negative bias voltage

    Institute of Scientific and Technical Information of China (English)

    陈国龙; 雷瑞瑞; 陈焕庭; 陈莹亮; 吕毅军; 高玉琳; 朱丽虹; 陈忠

    2012-01-01

    热阻是衡量LED器件散热性能的重要热学参数.采用外接负偏压恒压源方法,分别使用T3Ster/Teraled热光参数测试仪和NC2991热阻仪对正向电压超过仪器量程的同一型号功率型LED的热阻进行测试,并对两种测试结果的误差进行比较分析讨论.该方法拓展了热阻仪测量范围,使正向电压大于5V的LED器件/模块的热阻测试成为可能.%Thermal resistance is a key parameter on rating the heat dissipating capability of LEDs, so its measurement becomes particularly essential. A thermal resistance measurement method for high voltage LED device and module is provided here, which can measure LED sample with forward voltage larger than 5V by applying negative bias voltage to the T3Ster/Teraled and the NC2991 thermal resistance testers respectively. The results are further compared and discussed and prove to effectively expand the testing range of thermal resistance tester.

  10. Source of sustained voltage difference between the xylem of a potted Ficus benjamina tree and its soil.

    Directory of Open Access Journals (Sweden)

    Christopher J Love

    Full Text Available It has long been known that there is a sustained electrical potential (voltage difference between the xylem of many plants and their surrounding soil, but the mechanism behind this voltage has remained controversial. After eliminating any extraneous capacitive or inductive couplings and ground-mediated electric current flows, we have measured sustained differences of 50-200 mV between the xylem region of a Faraday-caged, intact, potted Ficus benjamina tree and its soil, as well as between its cut branches and soils and ionic solutions standardized to various pH values. Using identical platinum electrodes, no correlation between the voltage and time of day, illumination, sap flow, electrode elevation, or ionic composition of soil was found, suggesting no direct connection to simple dissimilar-metal redox reactions or transpirational activity. Instead, a clear relationship between the voltage polarity and magnitude and the pH difference between xylem and soil was observed. We attribute these sustained voltages to a biological concentration cell likely set up by the homeostatic mechanisms of the tree. Potential applications of this finding are briefly explored.

  11. A comparative study of different transformer connections for railway power supply- mitigation of voltage unbalance

    DEFF Research Database (Denmark)

    Firat, Gurkan; Yang, Guangya; Ali Hussain Al-Ali, Haider

    2015-01-01

    The railway represents a large power consumer that can cause uneven loading of the phases in the high voltage grid. These unbalanced loads supplied by the utility may lead to voltage unbalance problems in the system and thereby affects the other consumers connected to the same network. It is fact...... that, voltage unbalance appears mainly as a result of unbalanced currents at the points of common coupling drawn by unevenly distributed loads. Because of a significant amount of negative sequence current injected to the system, the power system components will suffer from consequent negative effects...... such as overheating, additional losses of lines and transformers, interference with communication systems etc. This paper presents a comparative study of some transformer connections which commonly used in railway supplying AC traction loads, for voltage unbalance mitigations. Simulations for comparison...

  12. Comprehensive Reactive Power Support of DFIG Adapted to Different Depth of Voltage Sags

    Directory of Open Access Journals (Sweden)

    Yangwu Shen

    2017-06-01

    Full Text Available The low voltage ride-through (LVRT capability of the doubly-fed induction generator (DFIG significantly impacts upon the integration of wind power into the power grid. This paper develops a novel comprehensive control strategy to enhance the LVRT and reactive power support capacities of the DFIG by installing the energy storage system (ESS. The ESS is connected to the DC-link capacitor of the DFIG and used to regulate the DC-link voltage during normal or fault operations. The unbalanced power between the captured wind power and the power injected to the grid during the transient process is absorbed or compensated by the ESS. The rotor-side converter (RSC is used to control the maximum power production and the grid-side converter (GSC is used to control the reactive power before participating in the voltage support. When the supply voltage continues to drop, the rotor speed is increased by controlling the RSC to realize the LVRT capability and help the GSC further enhance the reactive power support capability. The capacity of the GSC is dedicated to injecting the reactive power to the grid. An auxiliary transient pitch angle controller is proposed to protect the generator’s over speed. Both RSC and GSC act as reactive power sources to further enhance the voltage support capability with serious voltage sags. Simulations based on a single-machine infinite-bus power system verify the effectiveness of the developed comprehensive control strategy.

  13. Active power control with undead-band voltage & frequency droop applied to a meshed DC grid test system

    DEFF Research Database (Denmark)

    Vrana, Til Kristian; Zeni, Lorenzo; Fosso, Olav Bjarte

    2012-01-01

    A new method for controlling active power in HVDC grids has been tested on the meshed CIGRE B4 DC grid test system. The control strategy is based on the recently proposed undead-band droop control, which combines DC voltage and AC frequency droop. It provides sufficient roomm for optimisation...... for both normal and disturbed operation. Its main features are flexibility, reliability due to distributed control, easy expandability of the system and minimisation of communication needs. The control technique has been tested and its effectiveness has been verified to demonstrate its suitability...

  14. High voltage pulse generator

    Science.gov (United States)

    Fasching, George E.

    1977-03-08

    An improved high-voltage pulse generator has been provided which is especially useful in ultrasonic testing of rock core samples. An N number of capacitors are charged in parallel to V volts and at the proper instance are coupled in series to produce a high-voltage pulse of N times V volts. Rapid switching of the capacitors from the paralleled charging configuration to the series discharging configuration is accomplished by using silicon-controlled rectifiers which are chain self-triggered following the initial triggering of a first one of the rectifiers connected between the first and second of the plurality of charging capacitors. A timing and triggering circuit is provided to properly synchronize triggering pulses to the first SCR at a time when the charging voltage is not being applied to the parallel-connected charging capacitors. Alternate circuits are provided for controlling the application of the charging voltage from a charging circuit to be applied to the parallel capacitors which provides a selection of at least two different intervals in which the charging voltage is turned "off" to allow the SCR's connecting the capacitors in series to turn "off" before recharging begins. The high-voltage pulse-generating circuit including the N capacitors and corresponding SCR's which connect the capacitors in series when triggered "on" further includes diodes and series-connected inductors between the parallel-connected charging capacitors which allow sufficiently fast charging of the capacitors for a high pulse repetition rate and yet allow considerable control of the decay time of the high-voltage pulses from the pulse-generating circuit.

  15. Grid modeling, analysis and simulation of different scenarios for a smart low-voltage distribution grid

    DEFF Research Database (Denmark)

    Mihet-Popa, Lucian; Han, Xue; Bindner, Henrik W.

    2013-01-01

    , the number of cabinets and customers and the load per customer. The aim of the model is to design, implement and test the proposed configuration and to investigate whether the low-voltage distribution grid is prepared for the expected future increase of PV penetration, heat pumps and electric cars. The model...

  16. Calcium Release in Frog Cut Twitch Fibers Exposed to Different Ionic Environments under Voltage Clamp

    National Research Council Canada - National Science Library

    Hui, Chiu Shuen

    1999-01-01

    Calcium release was measured in highly stretched frog cut twitch fibers mounted in a double Vaseline-gap voltage clamp chamber, with the internal solution containing 20 mM EGTA plus 0.4 or 1.8 mM added calcium...

  17. The characteristics of electrical trees in the inner and outer layers of different voltage rating XLPE cable insulation

    Science.gov (United States)

    Xie, Ansheng; Li, Shengtao; Zheng, Xiaoquan; Chen, George

    2009-06-01

    The statistical initiation and propagation characteristics of electrical trees in cross-linked polyethylene (XLPE) cables with different voltage ratings from 66 to 500 kV were investigated under a constant test voltage of 50 Hz/7 kV (the 66 kV rating cable is from UK, the others from China). It was found that the characteristics of electrical trees in the inner region of 66 kV cable insulation differed considerably from those in the outer region under the same test conditions; however, no significant differences appeared in the 110 kV rating cable and above. The initiation time of electrical trees in both the inner and the outer regions of the 66 kV cable is much shorter than that in higher voltage rating cables; in addition the growth rate of electrical trees in the 66 kV cable is much larger than that in the higher voltage rating cables. By using x-ray diffraction, differential scanning calorimetry and thermogravimetry methods, it was revealed that besides the extrusion process, the molecular weight of base polymer material and its distribution are the prime factors deciding the crystallization state. The crystallization state and the impurity content are responsible for the resistance to electrical trees. Furthermore, it was proposed that big spherulites will cooperate with high impurity content in enhancing the initiation and growth processes of electrical trees via the 'synergetic effect'. Finally, dense and small spherulites, high crystallinity, high purity level of base polymer material and super-clean production processes are desirable for higher voltage rating cables.

  18. The characteristics of electrical trees in the inner and outer layers of different voltage rating XLPE cable insulation

    Energy Technology Data Exchange (ETDEWEB)

    Xie Ansheng; Li Shengtao; Zheng Xiaoquan [State Key Laboratory of Electrical Insulation and Power Equipment, Xi' an Jiaotong University, Xi' an 710049 (China); Chen, George, E-mail: sli@mail.xjtu.edu.c, E-mail: xieansheng@gmail.co, E-mail: xqzheng@mail.xjtu.edu.c, E-mail: gc@ecs.soton.ac.u [School of Electronics and Computer Science, University of Southampton, Southampton SO17 1BJ (United Kingdom)

    2009-06-21

    The statistical initiation and propagation characteristics of electrical trees in cross-linked polyethylene (XLPE) cables with different voltage ratings from 66 to 500 kV were investigated under a constant test voltage of 50 Hz/7 kV (the 66 kV rating cable is from UK, the others from China). It was found that the characteristics of electrical trees in the inner region of 66 kV cable insulation differed considerably from those in the outer region under the same test conditions; however, no significant differences appeared in the 110 kV rating cable and above. The initiation time of electrical trees in both the inner and the outer regions of the 66 kV cable is much shorter than that in higher voltage rating cables; in addition the growth rate of electrical trees in the 66 kV cable is much larger than that in the higher voltage rating cables. By using x-ray diffraction, differential scanning calorimetry and thermogravimetry methods, it was revealed that besides the extrusion process, the molecular weight of base polymer material and its distribution are the prime factors deciding the crystallization state. The crystallization state and the impurity content are responsible for the resistance to electrical trees. Furthermore, it was proposed that big spherulites will cooperate with high impurity content in enhancing the initiation and growth processes of electrical trees via the 'synergetic effect'. Finally, dense and small spherulites, high crystallinity, high purity level of base polymer material and super-clean production processes are desirable for higher voltage rating cables.

  19. Diffusion voltage in polymer light emitting diodes measured with electric field induced second harmonic generation

    Science.gov (United States)

    Kristensen, P. K.; Rafaelsen, J.; Pedersen, T. G.; Pedersen, K.

    2005-12-01

    We apply electric field induced second harmonic (EFISH) to polymer light emitting diodes (PLEDs) and demonstrate the ability to determine the diffusion voltage in PLED devices. The EFISH signal is proportional to the square of the effective field, which is the sum of the diffusion voltage and the applied voltage. By minimizing the EFISH-signal as a function of the applied voltage, the diffusion voltage is determined by measuring the applied voltage that cancels out the diffusion voltage. The PLEDs are fabricated with indium tin oxide (ITO) as the hole injecting contact and two different electron injecting contacts, namely aluminum and calcium. The diffusion voltage originates from the rearranged charges caused by the difference in Fermi levels in the materials in the PLEDs. Different contacts will thus cause different diffusion voltages. We demonstrate here that the EFISH signal is proportional to the square of the effective field in both reverse and forward bias, and discuss the dependence on contact materials.

  20. Quantitative determination of the mineral distribution in different collagen zones of calcifying tendon using high voltage electron microscopic tomography

    Science.gov (United States)

    McEwen, B. F.; Song, M. J.; Landis, W. J.

    1991-01-01

    High voltage electron microscopic tomography was used to make the first quantitative determination of the distribution of mineral between different regions of collagen fibrils undergoing early calcification in normal leg tendons of the domestic turkey, Meleagris gallopavo. The tomographic 3-D reconstruction was computed from a tilt series of 61 different views spanning an angular range of +/- 60 degrees in 2 degrees intervals. Successive applications of an interactive computer operation were used to mask the collagen banding pattern of either hole or overlap zones into separate versions of the reconstruction. In such 3-D volumes, regions specified by the mask retained their original image density while the remaining volume was set to background levels. This approach was also applied to the mineral crystals present in the same volumes to yield versions of the 3-D reconstructions that were masked for both the crystal mass and the respective collagen zones. Density profiles from these volumes contained a distinct peak corresponding only to the crystal mass. A comparison of the integrated density of this peak from each profile established that 64% of the crystals observed were located in the collagen hole zones and 36% were found in the overlap zones. If no changes in crystal stability occur once crystals are formed, this result suggests the possibilities that nucleation of mineral is preferentially and initially associated with the hole zones, nucleation occurs more frequently in the hole zones, the rate of crystal growth is more rapid in the hole zones, or a combination of these alternatives. All lead to the conclusion that the overall accumulation of mineral mass is predominant in the collagen hole zones compared to overlap zones during early collagen fibril calcification.

  1. The enhanced low dose rate sensitivity of a linear voltage regulator with different biases

    Institute of Scientific and Technical Information of China (English)

    Wang Yiyuan; Lu Wu; Ren Diyuan; Guo Qi; Yu Xuefeng; Gao Bo

    2011-01-01

    A linear voltage regulator was irradiated by 60Co γ at high and low dose rates with two bias conditions to investigate the dose rate effect.The devices exhibit enhanced low dose rate sensitivity (ELDRS) under both biases.Comparing the enhancement factors between zero and working biases,it was found that the ELDRS is more severe under zero bias conditions.This confirms that the ELDRS is related to the low electric field in a bipolar structure.The reasons for the change in the line regulation and the maximum drive current were analyzed by combining the principle of linear voltage regulator with irradiation response of the transistors and error amplifier in the regulator.This may be helpful for designing radiation hardened devices.

  2. On the difference between breakdown and quench voltages of argon plasma and its relation to $4p-4s$ atomic state transitions

    CERN Document Server

    Forati, Ebrahim; Sievenpiper, Dan

    2014-01-01

    Using a relaxation oscillator circuit, breakdown ($V_{\\mathrm{BD}}$) and quench ($V_{\\mathrm{Q}}$) voltages of a DC discharge microplasma between two needle probes are measured. High resolution modified Paschen curves are obtained for argon microplasmas including a quench voltage curve representing the voltage at which the plasma turns off. It is shown that, for a point to point microgap (e.g. the microgap between two needle probes) which describes many realistic microdevices, neither Paschen's law applies nor field emission is noticeable. Although normally $V_{\\mathrm{BD}}>V_{\\mathrm{Q}}$, it is observed that depending on environmental parameters of argon, such as pressure and the driving circuitry, plasma can exist in a different state with equal $V_{\\mathrm{BD}}$ and $V_{\\mathrm{Q}}$. Using emission line spectroscopy, it is shown that $V_{\\mathrm{BD}}$ and $V_{\\mathrm{Q}}$ are equal if the atomic excitation by the electric field dipole moment dominantly leads to one of the argon's metastable states ($4P_{5...

  3. On the difference between breakdown and quench voltages of argon plasma and its relation to 4p–4s atomic state transitions

    Energy Technology Data Exchange (ETDEWEB)

    Forati, Ebrahim, E-mail: forati@ieee.org; Piltan, Shiva; Sievenpiper, Dan, E-mail: dsievenpiper@ucsd.edu [University of California San Diego, La Jolla, California 92093 (United States)

    2015-02-02

    Using a relaxation oscillator circuit, breakdown (V{sub BD}) and quench (V{sub Q}) voltages of a DC discharge microplasma between two needle probes are measured. High resolution modified Paschen curves are obtained for argon microplasmas including a quench voltage curve representing the voltage at which the plasma turns off. It is shown that for a point to point microgap (e.g., the microgap between two needle probes) which describes many realistic microdevices, neither Paschen's law applies nor field emission is noticeable. Although normally V{sub BD} > V{sub Q,} it is observed that depending on environmental parameters of argon, such as pressure and the driving circuitry, plasma can exist in a different state with equal V{sub BD} and V{sub Q.} Using emission line spectroscopy, it is shown that V{sub BD} and V{sub Q} are equal if the atomic excitation by the electric field dipole moment dominantly leads to one of the argon's metastable states (4P{sub 5} in our study)

  4. Influence of applied voltage on the performance of bioelectrochemical anaerobic digestion of sewage sludge and planktonic microbial communities at ambient temperature.

    Science.gov (United States)

    Feng, Qing; Song, Young-Chae; Bae, Byung-Uk

    2016-11-01

    The influence of applied voltage on the bioelectrochemical anaerobic digestion of sewage sludge was studied at ambient temperature (25±2°C). The stability of the bioelectrochemical anaerobic digestion was considerably good in terms of pH, alkalinity and VFAs at 0.3V and 0.5V, but VFA accumulation occurred at 0.7V. The specific methane production rate (370mLCH4/L.d) was the highest at 0.3V, but the methane content (80.6%) in biogas and the methane yield (350mLCH4/gCODr) were higher at 0.5V, significantly better than those of 0.7V. The VS removal efficiency was 64-66% at 0.3V and 0.5V, but only 31% at 0.7V. The dominant species of planktonic microbial communities was Cloacamonas at 0.3V and 0.5V, but the percentage of hydrolytic bacteria species such as Saprospiraceae, Fimbriimonas, and Ottowia pentelensis was much higher at 0.7V. The optimal applied voltage for bioelectrochemical anaerobic digestion was 0.3-0.5V according to digestion performance and planktonic microbial communities.

  5. Development of theoretical approach for describing electronic properties of hetero-interface systems under applied bias voltage

    Science.gov (United States)

    Iida, Kenji; Noda, Masashi; Nobusada, Katsuyuki

    2017-02-01

    We have developed a theoretical approach for describing the electronic properties of hetero-interface systems under an applied electrode bias. The finite-temperature density functional theory is employed for controlling the chemical potential in their interfacial region, and thereby the electronic charge of the system is obtained. The electric field generated by the electronic charging is described as a saw-tooth-like electrostatic potential. Because of the continuum approximation of dielectrics sandwiched between electrodes, we treat dielectrics with thicknesses in a wide range from a few nanometers to more than several meters. Furthermore, the approach is implemented in our original computational program named grid-based coupled electron and electromagnetic field dynamics (GCEED), facilitating its application to nanostructures. Thus, the approach is capable of comprehensively revealing electronic structure changes in hetero-interface systems with an applied bias that are practically useful for experimental studies. We calculate the electronic structure of a SiO2-graphene-boron nitride (BN) system in which an electrode bias is applied between the graphene layer and an electrode attached on the SiO2 film. The electronic energy barrier between graphene and BN is varied with an applied bias, and the energy variation depends on the thickness of the BN film. This is because the density of states of graphene is so low that the graphene layer cannot fully screen the electric field generated by the electrodes. We have demonstrated that the electronic properties of hetero-interface systems are well controlled by the combination of the electronic charging and the generated electric field.

  6. Different approach to pulsed high-voltage vacuum-insulation design

    Directory of Open Access Journals (Sweden)

    John G. Leopold

    2007-06-01

    Full Text Available A theoretical methodology promising improved design of vacuum insulation in high-voltage pulsed-power systems is described. It consists of shaping the electromagnetic fields within the system in such a way that charged particles which can in principle initiate vacuum surface breakdown are deflected away from the insulator surface, and secondary electrons, if emitted, are prevented from restriking the surface. Thus, vacuum surface breakdown is prevented before it is able to develop. Our methodology is presented here by a set of case studies.

  7. Sequential injection of domain walls into ferroelectrics at different bias voltages: Paving the way for “domain wall memristors”

    Energy Technology Data Exchange (ETDEWEB)

    Whyte, J. R.; McQuaid, R. G. P.; Einsle, J. F.; Gregg, J. M., E-mail: m.gregg@qub.ac.uk [Centre for Nanostructured Media (CNM), School of Maths and Physics, Queen' s University Belfast, University Road, Belfast BT7 1NN (United Kingdom); Ashcroft, C. M. [Centre for Nanostructured Media (CNM), School of Maths and Physics, Queen' s University Belfast, University Road, Belfast BT7 1NN (United Kingdom); Department of Physics, Cavendish Laboratory, J. J. Thomson Avenue, Cambridge CB3 0HE (United Kingdom); Canalias, C. [Department of Applied Physics, Royal Institute of Technology, Roslagstullsbacken 21, 10691 Stockholm (Sweden); Gruverman, A. [Department of Physics and Astronomy, University of Nebraska Lincoln, Nebraska 68588–0299 (United States)

    2014-08-14

    Simple meso-scale capacitor structures have been made by incorporating thin (∼300 nm) single crystal lamellae of KTiOPO{sub 4} (KTP) between two coplanar Pt electrodes. The influence that either patterned protrusions in the electrodes or focused ion beam milled holes in the KTP have on the nucleation of reverse domains during switching was mapped using piezoresponse force microscopy imaging. The objective was to assess whether or not variations in the magnitude of field enhancement at localised “hot-spots,” caused by such patterning, could be used to both control the exact locations and bias voltages at which nucleation events occurred. It was found that both the patterning of electrodes and the milling of various hole geometries into the KTP could allow controlled sequential injection of domain wall pairs at different bias voltages; this capability could have implications for the design and operation of domain wall electronic devices, such as memristors, in the future.

  8. Implementation of fuzzy system using different voltages of OTA for JNK pathway leading to cell survival/ death

    Directory of Open Access Journals (Sweden)

    Shruti Jain

    2015-06-01

    Full Text Available In this paper a well defined method for the design of JNK pathway for epidermal growth factor/ insulin using fuzzy system using operational transconductance amplifier was discussed. Fuzzy system includes fuzzification of the input variables, application of the fuzzy operator (AND or OR in the antecedent, implication from the antecedent to the consequent, aggregation of the consequents across the rules, and defuzzfication. Fuzzy system with various electrical parameters for different voltages of OTA with different membership function was found. Results with 3V were the best.

  9. Nonstandard Finite Difference Method Applied to a Linear Pharmacokinetics Model

    Directory of Open Access Journals (Sweden)

    Oluwaseun Egbelowo

    2017-05-01

    Full Text Available We extend the nonstandard finite difference method of solution to the study of pharmacokinetic–pharmacodynamic models. Pharmacokinetic (PK models are commonly used to predict drug concentrations that drive controlled intravenous (I.V. transfers (or infusion and oral transfers while pharmacokinetic and pharmacodynamic (PD interaction models are used to provide predictions of drug concentrations affecting the response of these clinical drugs. We structure a nonstandard finite difference (NSFD scheme for the relevant system of equations which models this pharamcokinetic process. We compare the results obtained to standard methods. The scheme is dynamically consistent and reliable in replicating complex dynamic properties of the relevant continuous models for varying step sizes. This study provides assistance in understanding the long-term behavior of the drug in the system, and validation of the efficiency of the nonstandard finite difference scheme as the method of choice.

  10. Inverted Fuel Cell: Room-Temperature Hydrogen Separation from an Exhaust Gas by Using a Commercial Short-Circuited PEM Fuel Cell without Applying any Electrical Voltage.

    Science.gov (United States)

    Friebe, Sebastian; Geppert, Benjamin; Caro, Jürgen

    2015-06-26

    A short-circuited PEM fuel cell with a Nafion membrane has been evaluated in the room-temperature separation of hydrogen from exhaust gas streams. The separated hydrogen can be recovered or consumed in an in situ olefin hydrogenation when the fuel cell is operated as catalytic membrane reactor. Without applying an outer electrical voltage, there is a continuous hydrogen flux from the higher to the lower hydrogen partial pressure side through the Nafion membrane. On the feed side of the Nafion membrane, hydrogen is catalytically split into protons and electrons by the Pt/C electrocatalyst. The protons diffuse through the Nafion membrane, the electrons follow the short-circuit between the two brass current collectors. On the cathode side, protons and electrons recombine, and hydrogen is released. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  11. Potassium fertilizer applied by different methods in the zucchini crop

    Directory of Open Access Journals (Sweden)

    Carlos N. V. Fernandes

    Full Text Available ABSTRACT Aiming to evaluate the effect of potassium (K doses applied by the conventional method and fertigation in zucchini (Cucurbita pepo L., a field experiment was conducted in Fortaleza, CE, Brazil. The statistical design was a randomized block, with four replicates, in a 4 x 2 factorial scheme, which corresponded to four doses of K (0, 75, 150 and 300 kg K2O ha-1 and two fertilization methods (conventional and fertigation. The analyzed variables were: fruit mass (FM, number of fruits (NF, fruit length (FL, fruit diameter (FD, pulp thickness (PT, soluble solids (SS, yield (Y, water use efficiency (WUE and potassium use efficiency (KUE, besides an economic analysis using the net present value (NPV, internal rate of return (IRR and payback period (PP. K doses influenced FM, FD, PT and Y, which increased linearly, with the highest value estimated at 36,828 kg ha-1 for the highest K dose (300 kg K2O ha-1. This dose was also responsible for the largest WUE, 92 kg ha-1 mm-1. KUE showed quadratic behavior and the dose of 174 kg K2O ha-1 led to its maximum value (87.41 kg ha-1 (kg K2O ha-1-1. All treatments were economically viable, and the most profitable months were May, April, December and November.

  12. Comparative studies for different proximity potentials applied to α decay

    Energy Technology Data Exchange (ETDEWEB)

    Yao, Y.J.; Zhang, G.L. [Beihang University, School of Physics and Nuclear Energy Engineering, Beijing (China); Beihang University, International Research Center for Nuclei and Particles in the Cosmos, Beijing (China); Qu, W.W. [Medical College of Soochow University, School of Radiation Medicine and Protection, Soochow (China); Qian, J.Q. [Beihang University, School of Physics and Nuclear Energy Engineering, Beijing (China)

    2015-09-15

    Half-lives of α decay of even-even nuclei calculated by using fourteen different versions of proximity potentials are compared to experimental data. The results show that the results of the generalized proximity potential 1977 are very much in agreement with the experimental data. In comparison with the distributions of nuclear potentials at small distances and the distributions of total potentials above the released energy Q{sub α}, it is found that at small distances the distributions of nuclear potentials have large difference and the distributions of total potentials are different among the listed proximity potentials. The different potential distributions affect the penetration probability of α, which is related to the half-life of the α decay for each nucleus. The generalized proximity potential 1977 is also used to calculate the half-lives of α decay of nuclei with odd mass numbers. The results show that the generalized proximity potential 1977 can calculate the half-lives of the α decay of almost all nuclei, which underlines and supports the use of the generalized proximity potential 1977 by Santhosh et al. in the Coulomb and proximity potential model (CPPM) and the Coulomb and proximity potential model for deformed nuclei (CPPMDN). (orig.)

  13. Comparative studies for different proximity potentials applied to α decay

    Science.gov (United States)

    Yao, Y. J.; Zhang, G. L.; Qu, W. W.; Qian, J. Q.

    2015-09-01

    Half-lives of α decay of even-even nuclei calculated by using fourteen different versions of proximity potentials are compared to experimental data. The results show that the results of the generalized proximity potential 1977 are very much in agreement with the experimental data. In comparison with the distributions of nuclear potentials at small distances and the distributions of total potentials above the released energy Q α , it is found that at small distances the distributions of nuclear potentials have large difference and the distributions of total potentials are different among the listed proximity potentials. The different potential distributions affect the penetration probability of α, which is related to the half-life of the α decay for each nucleus. The generalized proximity potential 1977 is also used to calculate the half-lives of α decay of nuclei with odd mass numbers. The results show that the generalized proximity potential 1977 can calculate the half-lives of the α decay of almost all nuclei, which underlines and supports the use of the generalized proximity potential 1977 by Santhosh et al. in the Coulomb and proximity potential model (CPPM) and the Coulomb and proximity potential model for deformed nuclei (CPPMDN).

  14. Levitation performance of YBCO bulk in different applied magnetic fields

    Energy Technology Data Exchange (ETDEWEB)

    Liu, W. [Applied Superconductivity Laboratory, Southwest Jiaotong University, Chengdu 610031 (China)], E-mail: asclab@asclab.cn; Wang, S.Y.; Jing, H.; Zheng, J.; Jiang, M.; Wang, J.S. [Applied Superconductivity Laboratory, Southwest Jiaotong University, Chengdu 610031 (China)

    2008-07-01

    The maglev performance of bulk high-T{sub c} superconductor (HTS) is investigated above three different types of permanent magnet guideways (PMGs). The main difference among these PMGs is the method used to concentrate the magnetic flux. The experimental results indicate that the levitation force depends only in part on the peak value of the magnetic field. The variation of the vertical component of the magnetic field (B{sub z}), and the structure of the magnetic field are also responsible for the levitation force. These results imply that the permanent magnet with high coercive force is better at concentrating flux th an iron. The conclusions contribute in a very helpful way to the design and optimization of PMGs for HTS maglev systems.

  15. Nanotechnology-Applied Curcumin for Different Diseases Therapy

    Directory of Open Access Journals (Sweden)

    Negar Ghalandarlaki

    2014-01-01

    Full Text Available Curcumin is a lipophilic molecule with an active ingredient in the herbal remedy and dietary spice turmeric. It is used by different folks for treatment of many diseases. Recent studies have discussed poor bioavailability of curcumin because of poor absorption, rapid metabolism, and rapid systemic elimination. Nanotechnology is an emerging field that is potentially changing the way we can treat diseases through drug delivery with curcumin. The recent investigations established several approaches to improve the bioavailability, to increase the plasma concentration, and to enhance the cellular permeability processes of curcumin. Several types of nanoparticles have been found to be suitable for the encapsulation or loading of curcumin to improve its therapeutic effects in different diseases. Nanoparticles such as liposomes, polymeric nanoparticles, micelles, nanogels, niosomes, cyclodextrins, dendrimers, silvers, and solid lipids are emerging as one of the useful alternatives that have been shown to deliver therapeutic concentrations of curcumin. This review shows that curcumin’s therapeutic effects may increase to some extent in the presence of nanotechnology. The presented board of evidence focuses on the valuable special effects of curcumin on different diseases and candidates it for future clinical studies in the realm of these diseases.

  16. Flower Pollination Algorithm Applied for Different Economic Load Dispatch Problems

    Directory of Open Access Journals (Sweden)

    R. Prathiba

    2014-05-01

    Full Text Available Economic load dispatch (ELD is the main optimization task in power system operation. Minimizing the fuel cost by optimally setting the real power outputs from generators is the objective of ELD problem. In this work, ELD problem is addressed by considering three different cost functions. Real power generations are adjusted for minimizing the fuel cost by using flower pollination algorithm (FOA. This algorithm works on the basis of pollinating behavior of flowering plants. Unlike the other nature inspired algorithms, it follows only the levy flight mechanism for generating the population for the next generation. Being free from large number of parameters, the algorithm works well and there is no much difficulty in tuning to suit for different problems. The algorithm can be coded easily in any programming language. The proposed algorithm is tested on the standard IEEE-30 bus system and the results are compared with those of the other algorithms reported in the literature. The results are found to be improved and encouraging.

  17. Determination of Contact Potential Difference by the Kelvin Probe (Part II) 2. Measurement System by Involving the Composite Bucking Voltage

    Science.gov (United States)

    Vilitis, O.; Rutkis, M.; Busenbergs, J.; Merkulovs, D.

    2016-12-01

    The present research is devoted to creation of a new low-cost miniaturised measurement system for determination of potential difference in real time and with high measurement resolution. Furthermore, using the electrode of the reference probe, Kelvin method leads to both an indirect measurement of electronic work function or contact potential of the sample and measurement of a surface potential for insulator type samples. The bucking voltage in this system is composite and comprises a periodically variable component. The necessary steps for development of signal processing and tracking are described in detail.

  18. Evaluation of atrazine degradation applied to different energy systems.

    Science.gov (United States)

    Moreira, Ailton J; Pinheiro, Bianca S; Araújo, André F; Freschi, Gian P G

    2016-09-01

    Atrazine is an herbicide widely used in crops and has drawn attention due to potential pollution present in soil, sediment, water, and food. Since conventional methods are not potentially efficient to persistent degradation of organic compounds, new technology has been developed to remove them, especially practices utilizing advanced oxidation processes (AOPs). This work aims to evaluate the use of different energies (ultraviolet (UV), microwaves (MW), and radiations (MW-UV)) to the herbicide atrazine through the process of photo-oxidation. These systems found degradation rates of around 12 % (UV), 28 % (MW), and 83 % (MW-UV), respectively, with time intervals of 120 s. After the photolytic processes, the samples were analyzed at a wavelength scanning the range of 190 to 300 nm, where the spectral analysis of the signal was used to evaluate the degradation of atrazine and the appearance of some other peaks (degradation products). The spectrum evaluation resulting from photolytic processes gave rise to a new signal which was confirmed by chromatography. This spectrum indicated the possible pathway of atrazine degradation by the process of photolytic MW-UV, generating atrazine-2-hydroxy, atrazine-desethyl-2-hidroxy, and atrazine-desisopropyl-2-hydroxy. The process indicated that in all situations, chloride was present in the analytic structure and was substituted by a hydroxyl group, which lowered the toxicity of the compound through the photolytic process MW-UV. Chromatographic analysis ascertained these preliminary assessments using spectrophotometry. It was also significantly observed that the process can be optimized by adjusting the pH of the solution, which was evident by an improvement of 10 % in the rate of degradation when subjected to a pH solution equal to 8.37.

  19. The Calculation of Unbalanced Voltage on the tertiary bus of a single phase auto transformer in case of Parallel Operation with Different Manufacturer

    Energy Technology Data Exchange (ETDEWEB)

    Shim, E.B.; Woo, J.W.; Kwak, J.S. [Korea Electric Power Research Institute (Korea); Joe, S.H.; Hur, Y.H. [KEPCO (Korea); Han, S.O. [Chungnam University (Korea)

    2001-07-01

    This paper described the unbalanced voltage on the tertiary bus of a single phase auto transformer in the case of parallel operation with different manufacturer at each phase. The unbalanced capacitances between primary to secondary winding, secondary to tertiary winding and primary to tertiary winding makes unbalanced bus voltage in the tertiary bus side. The unbalanced voltage let the surge arrester to operate in the power frequency range, and it causes the arrester to burn out. The failure of the arrester at one phase makes line to ground fault, which lead to the surge arrester failure of the other two phase on the tertiary bus. (author). 3 refs., 10 figs., 2 tabs.

  20. Mixed voltage VLSI design

    Science.gov (United States)

    Panwar, Ramesh; Rennels, David; Alkalaj, Leon

    1993-01-01

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

  1. Molecular size of different neurotoxin receptors on the voltage-sensitive Na+ channel.

    Science.gov (United States)

    Barhanin, J; Schmid, A; Lombet, A; Wheeler, K P; Lazdunski, M; Ellory, J C

    1983-01-25

    Measurements were made of the molecular sizes of two distinct receptors on the Na+ channel in rat brain synaptosomes that are specific for different neurotoxins. Radiation inactivation of the binding of radiolabeled derivatives of the toxins was consistent with Mr = 260,000 for the tetrodotoxin receptor and Mr = 266,000 for the receptor specific for two scorpion toxins, toxin II from Centruroides suffusus suffusus and toxin gamma from Tityus serrulatus serrulatus. Covalent cross-linking of the latter to its receptor similarly indicated Mr = 270,000. It seems most likely that these two distinct receptors reside on the same molecule.

  2. Simulation of Five Phase Voltage Source Inverter with Different Excitation for Star Connected Load

    Directory of Open Access Journals (Sweden)

    M.A Inayathullaah

    2014-07-01

    Full Text Available In order to reduce the torque ripple and harmonics for smooth operation of the machine and to reduce the amount of heat generated the motor has to be supplied with multi phase supply greater than three phase supply. Selection of even number of phases should be avoided, because it decreases the performance of the motor as poles coincide with each other. So, Five Phase Supply is preferred. A five phase five leg 10 switch inverter fed five phase star connected load operating with five different excitation is simulated and compared with that of three phase conventional inverter.

  3. A SVPWM based on fluctuate capacitor voltage in 3L-NPC back-to-back converter applied to wind energy

    DEFF Research Database (Denmark)

    Chen, Quan; Wang, Qunjing; Chen, Zhe

    2014-01-01

    Three-level Neutral-point-clamped (3L-NPC) converters are becoming a realistic alternative to the conventional converters in high-power wind-energy applications. But the unbalance in the supported capacitors' voltage of back-to-back 3L-NPC converters, including the dynamics of the capacitors...... between the fluctuate voltage of upper and lower capacitors is extracted. Based on this error factor the duty-time of every active voltage vector is calculated. In order to validate the model and the control strategy proposed in this paper, a 2MW 3L-NPC converter used in wind energy has been simulated....

  4. Device for monitoring cell voltage

    Science.gov (United States)

    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.

  5. High Voltage Seismic Generator

    Science.gov (United States)

    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

  6. LHC RadMon SRAM Detectors Used at Different Voltages to Determine the Thermal Neutron to High Energy Hadron Fluence Ratio

    CERN Document Server

    Kramer, D; Pignard, C; Brugger, M; Spiezia, G; Roeed, K; Klupak, V; Wijnands, T

    2011-01-01

    The thermal neutron SEU cross-section of the Toshiba SRAM memory used in the LHC RadMon system was measured at different voltages. A method using the difference in its response compared to mixed particle energy field is proposed to be used as a discriminator between thermal neutron and high-energy hadron fluences. For test purposes, the proposed method was used at the CNGS and CERF facilities to estimate the field composition by counting SEUs at two different voltages and the results were compared to simulations.

  7. Technological Aspects: High Voltage

    CERN Document Server

    Faircloth, D C

    2013-01-01

    This paper covers the theory and technological aspects of high-voltage design for ion sources. Electric field strengths are critical to understanding high-voltage breakdown. The equations governing electric fields and the techniques to solve them are discussed. The fundamental physics of high-voltage breakdown and electrical discharges are outlined. Different types of electrical discharges are catalogued and their behaviour in environments ranging from air to vacuum are detailed. The importance of surfaces is discussed. The principles of designing electrodes and insulators are introduced. The use of high-voltage platforms and their relation to system design are discussed. The use of commercially available high-voltage technology such as connectors, feedthroughs and cables are considered. Different power supply technologies and their procurement are briefly outlined. High-voltage safety, electric shocks and system design rules are covered.

  8. Effects of in vitro lead exposure on voltage-sensitive calcium channels differ among cell types in central neurons of Lymnaea stagnalis.

    Science.gov (United States)

    Audesirk, G; Audesirk, T

    1989-01-01

    The effects of acute in vitro lead exposure on slowly inactivating voltage-sensitive calcium channels in central neurons of the freshwater pond snail Lymnaea stagnalis were studied under voltage clamp. Three physiologically distinct cell types were used: two subsets of the B cell cluster (Bpos and Bneg) and the pedal giant neuron (RPeD1). In Bpos neurons, 5 nM free Pb2+ irreversibly inhibited current flow through calcium channels by 38 +/- 10%. In Bneg neurons, 5 nM free Pb2+ slightly inhibited inward currents (12 +/- 6%) and may have shifted their voltage dependence to more depolarized voltages. The inhibition and voltage shift were irreversible. In RPeD1 neurons, Pb2+ caused a small, statistically insignificant inhibition of inward current (5 nM free Pb2+; 18 +/- 19%; 30 nM free Pb2+: 31 +/- 23%). The effects of Pb2+ were fully reversible. These data indicate that (1) voltage-sensitive calcium channels in Lymnaea neurons are inhibited by nanomolar concentrations of free Pb2+; (2) there are multiple types of calcium channels in Lymnaea neurons; and (3) the effects of in vitro lead exposure differ qualitatively among channel types.

  9. 动态电压恢复器的快速检测及补偿策略%Fast Detection and Compensation Strategy Applied for Dynamic Voltage Restorer

    Institute of Scientific and Technical Information of China (English)

    杨浩; 王宇; 石巍; 方太勋; 刘为群

    2015-01-01

    Low voltage ride through(LVRT)is an important technical problem for power quality.In order to study LVRT,this paper designed an LVRT experimental system composed of dynamic voltage restorer(DVR),and used voltage dq integrated value and its change rate as detection criterion for voltage drops,and used the voltage feed forward and resonance control loop as the compensation strategy,which can achieve fast compensation of low voltage power grid fault.The experiment is completed using above platform.The test results show that DVR which adopts above detection and compensation strategy can achieve the compensation for low voltage fault quickly.%为了研究低电压穿越问题,设计了一套由动态电压恢复器组成的低电压穿越试验系统。提出采用电压 dq 综合值结合其变化率作为低电压故障发生检测判据,采用电压差前馈结合谐振控制环作为补偿策略,实现对电网低电压故障的快速补偿。经电压补偿试验表明,采用上述低电压故障检测及补偿策略的动态电压恢复器能够快速实现电压补偿。

  10. Current-voltage characteristics of Bi{sub 2}Sr{sub 2}Ca{sub 2}Cu{sub 3}O{sub 10+x}/Ag multifilamentary tapes in zero applied magnetic field

    Energy Technology Data Exchange (ETDEWEB)

    Crisan, A. [Institute of Cryogenics, University of Southampton, Southampton (United Kingdom); Institute of Physics and Technology of Materials, Bucharest (Romania); Miu, L.; Popa, S. [Institute of Physics and Technology of Materials, Bucharest (Romania); Yang, Y.; Beduz, C. [Institute of Cryogenics, University of Southampton, Southampton (United Kingdom)

    1997-05-01

    Current-voltage characteristics of multifilamentary Bi{sub 2}Sr{sub 2}Ca{sub 2}Cu{sub 3}O{sub 10+x}/Ag tapes (short samples) produced by the 'powder in tube' technique were measured at different temperatures close to the mean-field critical temperature, and inzero applied magnetic field. After performing the required corrections due to the current flowing in the silver matrix, the I-V curves were interpreted in terms of current-induced unbinding of the thermally created vortex-antivortex pairs. Two possible mechanisms for appearance of a finite critical current in zero applied magnetic field are discussed: the Jensen-Minnhagen quasi-two-dimensional (2D) approach, that takes into account the interlayer Josephson coupling, and a model of size limitation of vortex fluctuations. From our analysis, it seems that the latter model is more suitable for this kind of superconducting material, due probably to an accentuated intrinsic anisotropy. (author)

  11. Numerical Simulation of Voltage Electric Field in Complex Geometries for Different Electrode Arrangements using Meshless Local MQ-DQ Method

    DEFF Research Database (Denmark)

    Jalaal, M.; Soleimani, Soheil; Domairry, G.

    2011-01-01

    In this paper the meshless Local Multi Quadrics-based Differential Quadrature (MQ-DQ) method is applied to obtain the electric field distribution for different applicable irregular geometries. This method is the combination of Differential Quadrature approximation of derivatives and function...... with FEM and this fact that MQ-DQ method is an accurate and flexible method in solution of electrostatic equations....

  12. Suppression of endurance degradation by applying constant voltage stress in one-transistor and one-resistor resistive random access memory

    Science.gov (United States)

    Su, Yu-Ting; Chang, Ting-Chang; Tsai, Tsung-Ming; Chang, Kuan-Chang; Chu, Tian-Jian; Chen, Hsin-Lu; Chen, Min-Chen; Yang, Chih-Cheng; Huang, Hui-Chun; Lo, Ikai; Zheng, Jin-Cheng; Sze, Simon M.

    2017-01-01

    In this letter we demonstrate an operation method that effectively suppresses endurance degradation. After many operations, the off-state of resistance random access memory (RRAM) degrades. This degradation is caused by reduction of active oxygen ions participating in the set process, as determined by current fitting of current-voltage (I-V) curves obtained from the endurance test between the interval of seventy to one hundred million operations. To address this problem, we propose the application of constant voltage stress after every five million operations during the endurance test. The experimental result shows that this method can maintain oxygen ions at the proper depth in the electrode and improve RRAM reliability.

  13. Applying the Different Statistical Tests in Analysis of Electrical Breakdown Mechanisms in Nitrogen Filled Gas Diode

    Science.gov (United States)

    Čedomir, A. Maluckov; Saša, A. Rančev; Miodrag, K. Radović

    2016-10-01

    This paper presents the results of our investigations of breakdown mechanisms, as well as a description of their influence on the distributions of time delay distributions, for a gas tube filled with nitrogen at 4 mbar. The values of the time delay are measured for different voltages, and the values of the relaxation times and their distributions and probability plots are analyzed. The obtained density distributions have Gaussian distributions and exponential distributions for different values of relaxation times (Gaussian for small values and exponential for large values of relaxation time). It is shown that for middle values of relaxation time the delay distributions have a shape between Gaussian and exponential distributions, which is a result of the different influences of electrical breakdown.

  14. Thermal power transfer system using applied potential difference to sustain operating pressure difference

    Science.gov (United States)

    Bhandari, Pradeep (Inventor); Fujita, Toshio (Inventor)

    1991-01-01

    A thermal power transfer system using a phase change liquid gas fluid in a closed loop configuration has a heat exchanger member connected to a gas conduit for inputting thermal energy into the fluid. The pressure in the gas conduit is higher than a liquid conduit that is connected to a heat exchanger member for outputting thermal energy. A solid electrolyte member acts as a barrier between the gas conduit and the liquid conduit adjacent to a solid electrolyte member. The solid electrolyte member has the capacity of transmitting ions of a fluid through the electrolyte member. The ions can be recombined with electrons with the assistance of a porous electrode. An electrical field is applied across the solid electrolyte member to force the ions of the fluid from a lower pressure liquid conduit to the higher pressure gas conduit.

  15. Numerical Simulations of Electrokinetic Processes Comparing the Use of a Constant Voltage Difference or a Constant Current as Driving Force

    DEFF Research Database (Denmark)

    Paz-Garcia, Juan Manuel; Johannesson, Björn; Ottosen, Lisbeth M.

    materials and the prevention of the reinforced concrete corrosion. The electrical energy applied in an electrokinetic process produces electrochemical reactions at the electrodes. Different electrode processes can occur. When considering inert electrodes in aqueous solutions, the reduction of water...... are transported from the anode to the cathode through the closed electrical circuit of the cell. In the solution, the electrical current is carried by the ions, which move towards the electrode with different charge. Therefore, different authors have studied the system using the circuit theory. Assuming...

  16. Effects of Controlled Release Urea on Wheat Yield and Nitrogen Utilization Efficiency Under Different Applied Conditions

    OpenAIRE

    XIA Wei-guang; Wu, Ji; GAO Feng-me; WANG, YUN-QING; GUO Xi-sheng

    2014-01-01

    The field trial was conducted to study the effects of different nitrogen fertilizer applications on winter wheat yield, nitrogen utilization efficiency and economic benefit. 7 treatments were designed as CK(no nitrogen fertilizer applied), 100%PU10/0(conventional urea applied before sowing, N rate was 240 kg·hm-2), 100%PU6/4(conventional urea applied before sowing and at jointing with the ratio of 6∶4, N rate was 240 kg·hm-2), 80%PU6/4(conventional urea applied before sowing and at jointing w...

  17. Effects of Controlled Release Urea on Wheat Yield and Nitrogen Utilization Efficiency Under Different Applied Conditions

    OpenAIRE

    XIA Wei-guang; Wu, Ji; GAO Feng-me; WANG Yun-qing; GUO Xi-sheng

    2014-01-01

    The field trial was conducted to study the effects of different nitrogen fertilizer applications on winter wheat yield, nitrogen utilization efficiency and economic benefit. 7 treatments were designed as CK(no nitrogen fertilizer applied), 100%PU10/0(conventional urea applied before sowing, N rate was 240 kg·hm-2), 100%PU6/4(conventional urea applied before sowing and at jointing with the ratio of 6∶4, N rate was 240 kg·hm-2), 80%PU6/4(conventional urea applied before sowing and at jointing w...

  18. CONTRIBUTIONS OF INTRACELLULAR IONS TO Kv CHANNEL VOLTAGE SENSOR DYNAMICS.

    Directory of Open Access Journals (Sweden)

    Samuel eGoodchild

    2012-06-01

    Full Text Available Voltage sensing domains of Kv channels control ionic conductance through coupling of the movement of charged residues in the S4 segment to conformational changes at the cytoplasmic region of the pore domain, that allow K+ ions to flow. Conformational transitions within the voltage sensing domain caused by changes in the applied voltage across the membrane field are coupled to the conducting pore region and the gating of ionic conductance. However, several other factors not directly linked to the voltage dependent movement of charged residues within the voltage sensor impact the dynamics of the voltage sensor, such as inactivation, ionic conductance, intracellular ion identity and block of the channel by intracellular ligands. The effect of intracellular ions on voltage sensor dynamics is of importance in the interpretation of gating current measurements and the physiology of pore/voltage sensor coupling. There is a significant amount of variability in the reported kinetics of voltage sensor deactivation kinetics of Kv channels attributed to different mechanisms such as open state stabilization, immobilization and relaxation processes of the voltage sensor. Here we separate these factors and focus on the causal role that intracellular ions can play in allosterically modulating the dynamics of Kv voltage sensor deactivation kinetics. These considerations are of critical importance in understanding the molecular determinants of the complete channel gating cycle from activation to deactivation.

  19. Recombination dynamics as a key determinant of open circuit voltage in organic bulk heterojunction solar cells: a comparison of four different donor polymers

    Energy Technology Data Exchange (ETDEWEB)

    Maurano, Andrea; Hamilton, Rick; Shuttle, Chris G.; O' Regan, Brian; Zhang, Weimin; McCulloch, Iain; Durrant, James R. [Departments of Chemistry, Imperial College London, South Kensington SW7 2AZ (United Kingdom); Ballantyne, Amy M.; Nelson, Jenny [Departments of Physics, Imperial College London, South Kensington SW7 2AZ (United Kingdom); Azimi, Hamed [Konarka Austria, Altenbergerstrasse 69, A-4040 Linz (Austria); Christian Doppler Laboratory for Surface Optics, Johannes Kepler University, Linz (Austria); Morana, Mauro; Brabec, Christoph J. [Konarka Austria, Altenbergerstrasse 69, A-4040 Linz (Austria)

    2010-11-24

    Transient photovoltage and charge extraction analyses are employed to analyzes charge carrier densities and bimolecular recombination dynamics in organic polymer: fullerene solar cells under open circuit operating conditions, employing four different donor polymers. An equation is derived which allows us to calculate the device V{sub OC} from these kinetic measurements. This equation allows us to calculate voltage output of devices within {+-} 25 meV of directly measured values. This analysis thus allows us to relate device open circuit voltage directly to the kinetics of bimolecular recombination, and thereby the influence of nanomorphology upon device voltage output. (Copyright copyright 2010 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  20. Elastic and Muscular Arteries Differ in Structure, Basal NO Production and Voltage-Gated Ca(2+)-Channels.

    Science.gov (United States)

    Leloup, Arthur J A; Van Hove, Cor E; Heykers, Annick; Schrijvers, Dorien M; De Meyer, Guido R Y; Fransen, Paul

    2015-01-01

    In the last decades, the search for mechanisms underlying progressive arterial stiffening and for interventions to avoid or reverse this process has gained much attention. In general, arterial stiffening displays regional variation and is, for example, during aging more prominent in elastic than in muscular arteries. We hypothesize that besides passive also active regulators of arterial compliance [i.e., endothelial and vascular smooth muscle cell (VSMC) function] differ between these arteries. Hence, it is conceivable that these vessel types will display different time frames of stiffening. To investigate this hypothesis segments of muscular arteries such as femoral and mesenteric arteries and elastic arteries such as the aorta and carotid artery were isolated from female C57Bl6 mice (5-6 months of age, n = 8). Both microscopy and passive stretching of the segments in a myograph confirmed that passive mechanical properties (elastin, collagen) of elastic and muscular arteries were significantly different. Endothelial function, more specifically basal nitric oxide (NO) efficacy, and VSMC function, more specifically L-type voltage-gated Ca(2+) channel (VGCC)-mediated contractions, were determined by α1-adrenoceptor stimulation with phenylephrine (PE) and by gradual depolarization with elevated extracellular K(+) in the absence and presence of eNOS inhibition with L-NAME. PE-mediated isometric contractions significantly increased after inhibition of NO release with L-NAME in elastic, but not in muscular vessel segments. This high basal eNOS activity in elastic vessels was also responsible for shifts of K(+) concentration-contraction curves to higher external K(+). VGCC-mediated contractions were similarly affected by depolarization with elevated K(+) in muscular artery segments or in elastic artery segments in the absence of basal NO. However, K(+)-induced contractions were inhibited by the VGCC blocker diltiazem with significantly higher sensitivity in the muscular

  1. Elastic and muscular arteries differ in structure, basal NO production and voltage-gated Ca2+-channels

    Directory of Open Access Journals (Sweden)

    Arthur J.A. Leloup

    2015-12-01

    Full Text Available In the last decades, the search for mechanisms underlying progressive arterial stiffening and for interventions to avoid or reverse this process has gained much attention. In general, arterial stiffening displays regional variation and is, for example, during aging more prominent in elastic than in muscular arteries. We hypothesize that besides passive also active regulators of arterial compliance (i.e. endothelial and vascular smooth muscle cell (VSMC function differ between these arteries. Hence, it is conceivable that these vessel types will display different time frames of stiffening. To investigate this hypothesis segments of muscular arteries such as femoral and mesenteric arteries and elastic arteries such as the aorta and carotid artery were isolated from female C57Bl6 mice (5-6 months of age, n=8. Both microscopy and passive stretching of the segments in a myograph confirmed that passive mechanical properties (elastin, collagen of elastic and muscular arteries were significantly different. Endothelial function, more specifically basal nitric oxide (NO efficacy, and VSMC function, more specifically L-type voltage-gated Ca2+ channel (VGCC-mediated contractions, were determined by α1-adrenoceptor stimulation with phenylephrine (PE and by gradual depolarization with elevated extracellular K+ in the absence and presence of eNOS inhibition with L-NAME. PE-mediated isometric contractions significantly increased after inhibition of NO release with L-NAME in elastic, but not in muscular vessel segments. This high basal eNOS activity in elastic vessels was also responsible for shifts of K+ concentration-contraction curves to higher external K+. VGCC-mediated contractions were similarly affected by depolarization with elevated K+ in muscular artery segments or in elastic artery segments in the absence of basal NO. However, K+-induced contractions were inhibited by the VGCC blocker diltiazem with significantly higher sensitivity in the muscular

  2. Study on the influence of applied voltage and feed concentration on the performance of electrodeionization in nickel recovery from electroplating wastewater

    Science.gov (United States)

    Wardani, Anita K.; Hakim, Ahmad N.; Khoiruddin, Destifen, Welsen; Goenawan, Albertus; Wenten, I. G.

    2017-01-01

    Wastewaters from electroplating industries are usually contaminated with nickel up to 1000 mg/L. According to environmental regulations worldwide, nickel concentration on wastewaters must be controlled to an acceptable level before being discharged to the environment. This paper offers an alternative way to develop an efficient effluent-free technology to reduce the nickel content of rinse water so that the treated water could be recycled for rinsing and subsequently to workout methodology to recover nickel by electrodeionization (EDI). Electrical voltage and initial nickel concentration were varied to study the effect of the parameters. Results showed that EDI could remove nickel effectively which gives an outstanding result in terms of product quality. Nickel concentration on diluate chamber decreased up to 99% after 60 and 180 minutes for nickel concentration of 300 and 1000 mg/L, respectively. Meanwhile, the increase of electrical voltage led to faster nickel removal.

  3. Observation of applied voltage response of dye-doped liquid crystal by optical measurement of real and imaginary parts of complex refractive index

    Science.gov (United States)

    Sakamoto, Moritsugu; Bannai, Kenta; Noda, Kohei; Sasaki, Tomoyuki; Ono, Hiroshi

    2017-09-01

    The behavior of liquid crystal (LC) molecules and dye molecules in a dye-doped liquid crystal (DDLC) under a voltage application condition was quantitatively investigated. To observe the reorientation of these molecules, the real and imaginary parts of the complex refractive index were simultaneously and individually measured using an optical interferometer. The obtained results indicate that the alignment of dye molecules doped in DDLC occurs following the electrically responding LC molecules, near the Freedericksz transition region of LC.

  4. SIMULACIÓN DE MONTE CARLO APLICADA A LA ESTIMACIÓN DE DEPRESIONES RÁPIDAS DE LA TENSIÓN EN REDES ELÉCTRICAS MONTE CARLO SIMULATION APPLIED TO THE ESTIMATION OF VOLTAGE DIPS IN ELECTRIC NETWORKS

    Directory of Open Access Journals (Sweden)

    Miguel Arias Albornoz

    2008-09-01

    Full Text Available En este trabajo se aplica el método de simulación de Monte Carlo (MC para estimar el número de depresiones rápidas de tensión (dips esperados en barras de una red eléctrica. Las estimaciones obtenidas a través de MC se comparan con los resultados de otro método de cálculo conocido como Método de Posiciones de Falla (MPF. Entre los resultados se muestra tanto la convergencia del algoritmo MC a los valores de largo plazo del método MPF como la distribución completa de frecuencias para diferentes eventos, lo cual representa información valiosa para apoyar la toma de decisiones sobre el empleo de equipos sensibles a este tipo de perturbación.In this work, the Monte Carlo simulation method (MC is applied to estimate the number of expected voltage dips in the nodes of an electric network. The estimations obtained through MC are compared with the results of another method of calculation, known as Failure Position Method (MPF. In the results, both the convergence of the algorithm with the long-term values of the MPF method and the complete distribution of frequencies for different events are shown. This represents valuable information to support the decision-making process for equipment that is sensitive to this type of perturbation.

  5. High Light Absorption and Charge Separation Efficiency at Low Applied Voltage from Sb-Doped SnO2/BiVO4 Core/Shell Nanorod-Array Photoanodes.

    Science.gov (United States)

    Zhou, Lite; Zhao, Chenqi; Giri, Binod; Allen, Patrick; Xu, Xiaowei; Joshi, Hrushikesh; Fan, Yangyang; Titova, Lyubov V; Rao, Pratap M

    2016-06-08

    BiVO4 has become the top-performing semiconductor among photoanodes for photoelectrochemical water oxidation. However, BiVO4 photoanodes are still limited to a fraction of the theoretically possible photocurrent at low applied voltages because of modest charge transport properties and a trade-off between light absorption and charge separation efficiencies. Here, we investigate photoanodes composed of thin layers of BiVO4 coated onto Sb-doped SnO2 (Sb:SnO2) nanorod-arrays (Sb:SnO2/BiVO4 NRAs) and demonstrate a high value for the product of light absorption and charge separation efficiencies (ηabs × ηsep) of ∼51% at an applied voltage of 0.6 V versus the reversible hydrogen electrode, as determined by integration of the quantum efficiency over the standard AM 1.5G spectrum. To the best of our knowledge, this is one of the highest ηabs × ηsep efficiencies achieved to date at this voltage for nanowire-core/BiVO4-shell photoanodes. Moreover, although WO3 has recently been extensively studied as a core nanowire material for core/shell BiVO4 photoanodes, the Sb:SnO2/BiVO4 NRAs generate larger photocurrents, especially at low applied voltages. In addition, we present control experiments on planar Sb:SnO2/BiVO4 and WO3/BiVO4 heterojunctions, which indicate that Sb:SnO2 is more favorable as a core material. These results indicate that integration of Sb:SnO2 nanorod cores with other successful strategies such as doping and coating with oxygen evolution catalysts can move the performance of BiVO4 and related semiconductors closer to their theoretical potential.

  6. Molecular and functional differences in voltage-activated sodium currents between GABA projection neurons and dopamine neurons in the substantia nigra

    OpenAIRE

    Ding, Shengyuan; Wei, Wei; Zhou, Fu-Ming

    2011-01-01

    GABA projection neurons (GABA neurons) in the substantia nigra pars reticulata (SNr) and dopamine projection neurons (DA neurons) in substantia nigra pars compacta (SNc) have strikingly different firing properties. SNc DA neurons fire low-frequency, long-duration spikes, whereas SNr GABA neurons fire high-frequency, short-duration spikes. Since voltage-activated sodium (NaV) channels are critical to spike generation, the different firing properties raise the possibility that, compared with DA...

  7. Deployment of low-voltage regulator considering existing voltage control in medium-voltage distribution systems

    Directory of Open Access Journals (Sweden)

    Hiroshi Kikusato

    2016-01-01

    Full Text Available Many photovoltaic (PV systems have been installed in distribution systems. This installation complicates the maintenance of all voltages within the appropriate range in all low-voltage distribution systems (LVDSs because the trends in voltage fluctuation differ in each LVDS. The installation of a low-voltage regulator (LVR that can accordingly control the voltage in each LVDS has been studied as a solution to this problem. Voltage control in a medium-voltage distribution system must be considered to study the deployment of LVRs. In this study, we installed LVRs in the LVDSs in which the existing voltage-control scheme cannot prevent voltage deviation and performed a numerical simulation by using a distribution system model with PV to evaluate the deployment of the LVRs.

  8. Transient voltage sharing in series-coupled high voltage switches

    Directory of Open Access Journals (Sweden)

    Editorial Office

    1992-07-01

    Full Text Available For switching voltages in excess of the maximum blocking voltage of a switching element (for example, thyristor, MOSFET or bipolar transistor such elements are often coupled in series - and additional circuitry has to be provided to ensure equal voltage sharing. Between each such series element and system ground there is a certain parasitic capacitance that may draw a significant current during high-speed voltage transients. The "open" switch is modelled as a ladder network. Analy­sis reveals an exponential progression in the distribution of the applied voltage across the elements. Overstressing thus oc­curs in some of the elements at levels of the total voltage that are significantly below the design value. This difficulty is overcome by grading the voltage sharing circuitry, coupled in parallel with each element, in a prescribed manner, as set out here.

  9. Multiple High Voltage Pulse Stressing of Polymer Thick Film Resistors

    Directory of Open Access Journals (Sweden)

    Busi Rambabu

    2014-01-01

    Full Text Available The purpose of this paper is to study high voltage interactions in polymer thick film resistors, namely, polyvinyl chloride- (PVC- graphite thick film resistors, and their applications in universal trimming of these resistors. High voltages in the form of impulses for various pulse durations and with different amplitudes have been applied to polymer thick film resistors and we observed the variation of resistance of these resistors with high voltages. It has been found that the resistance of polymer thick film resistors decreases in the case of higher resistivity materials and the resistance of polymer thick film resistor increases in the case of lower resistivity materials when high voltage impulses are applied to them. It has been also found that multiple high voltage pulse (MHVP stressing can be used to trim the polymer thick film resistors either upwards or downwards.

  10. The effects of inorganic lead on voltage-sensitive calcium channels differ among cell types and among channel subtypes.

    Science.gov (United States)

    Audesirk, G; Audesirk, T

    1993-01-01

    The whole-cell version of patch clamping was used to compare the effects of acute in vitro exposure to inorganic lead (Pb2+) on voltage-sensitive calcium channels in cultured N1E-115 mouse neuroblastoma cells and E18 rat hippocampal neurons. Free Pb2+ concentrations in salines with a high lead-buffering capacity were measured with a calibrated Pb(2+)-selective electrode. Previously, we found that N1E-115 neurons contain low voltage activated, rapidly inactivating (T) channels and high voltage activated, slowly inactivating (L) channels. Pb2+ inhibits both channel subtypes in N1E-115 cells, with some selectivity against L-type channels (IC50 approximately 700 nM free Pb2+ for L-type channels, 1300 nM free Pb2+ for T-type channels; Audesirk and Audesirk, 1991). In addition to T-type and L-type channels, cultured E18 rat hippocampal neurons have been reported to contain high voltage-activated, rapidly inactivating (N) channels. In our experiments with 5 to 20 day old cultures, almost all neurons showed substantial L-type current, approximately half showed significant N-type current, and fewer than 5% showed significant T-type current. We found that Pb2+ is somewhat selective against L-type channels (IC50 approximately 30 nM free Pb2+ in 10 mM Ba2+ as the charge carrier, 55 nM in 50 mM Ba2+) compared to N-channels (IC50 approximately 80 nM free Pb2+ in 10 mM Ba2+, 200 nM in 50 mM Ba2+). These results suggest that the effects of Pb2+ on calcium channels of vertebrate neurons vary both among cell types and among channel subtypes.

  11. Comparative Analysis of Different PWM Techniques to Reduce the Common Mode Voltage in Three-Level Neutral-Point-Clamped Inverters for Variable Speed Induction Drives

    Directory of Open Access Journals (Sweden)

    Bharati Raja

    2012-12-01

    Full Text Available This work presents the comparative study of the different PWM techniques to reduce the common-mode voltage (CMV at the output of neutral point diode clamped inverter for variable speed drives. Here the comparative study is done by the phase opposition disposed (POD, sinusoidal pulse width modulation (SPWM, phase disposition (PD, phase shift (PS space vector modulation (SVM techniques are proposed. A good trade-off between the quality of the output voltage and the partial magnitude of the CMV is achieved in this work. The scheme is proposed for three-level inverter. This work realizes the implementation of Three-level diode clamped MLI for three-phase (Y-Δ induction motor with the implementation of a space vector modulation technique without any additional control algorithm to reduce CMV within the range + Vdc/6. The Simulation with a 1HP induction motor drive system is setup in Matlab-2011b  and the same results validated effectively by hardware – FPGA-SPARTEN III processor and its shows that the CM voltage is effectively reduced and the maximum output voltage is not affected.  

  12. Recommendations for learners are different: Applying memory-based recommender system techniques to lifelong learning

    NARCIS (Netherlands)

    Drachsler, Hendrik; Hummel, Hans; Koper, Rob

    2007-01-01

    Drachsler, H., Hummel, H. G. K., & Koper, R. (2007). Recommendations for learners are different: applying memory-based recommender system techniques to lifelong learning. Paper presented at the SIRTEL workshop at the EC-TEL 2007 Conference. September, 17-20, 2007, Crete, Greece.

  13. Google's Web Page Ranking Applied to Different Topological Web Graph Structures.

    Science.gov (United States)

    Meghabghab, George

    2001-01-01

    This research, part of the ongoing study to better understand Web page ranking on the Web, looks at a Web page as a graph structure or Web graph, and classifies different Web graphs in the new coordinate space (out-degree, in-degree). Google's Web ranking algorithm (Brin & Page, 1998) on ranking Web pages is applied in this new coordinate…

  14. Shifted Excitation Raman Difference Spectroscopy applied to extraterrestrial particles returned from the asteroid Itokawa

    Science.gov (United States)

    Böttger, U.; Maiwald, M.; Hanke, F.; Braune, M.; Pavlov, S. G.; Schröder, S.; Weber, I.; Busemann, H.; Sumpf, B.; Tränkle, G.; Hübers, H.-W.

    2017-09-01

    Two extraterrestrial particles from the asteroid Itokawa are investigated applying Shifted Excitation Raman Difference Spectroscopy (SERDS). These particles were returned by the Hayabusa mission of the Japanese Space Agency JAXA. For SERDS a diode laser based microsystem light source at 488 nm is used for excitation. It has been found that fluorescence signals masking the Raman spectral features of interest can be substantially separated by applying SERDS. Therefore, SERDS improves the information obtained from the Raman spectra and enables a reliable analysis for investigations on extraterrestrial samples.

  15. Mitigation of Voltage Sags in CIGRE Low Voltage Distribution Network

    DEFF Research Database (Denmark)

    Mustafa, Ghullam; Bak-Jensen, Birgitte; Mahat, Pukar;

    2013-01-01

    problems in the distribution system. The voltage problems dealt with in this paper are to show how to mitigate voltage sags in the CIGRE Low Voltage (LV) test network and networks like this. The voltage sags, for the tested cases in the CIGRE LV test network are mainly due to three phase faults....... The compensation of voltage sags in the different parts of CIGRE distribution network is done by using the four STATCOM compensators already existing in the test grid. The simulations are carried out in DIgSILENT power factory software version 15.0....

  16. Simulation Research of Transient Over-voltage on High-voltage Shunt Capacitor Banks

    Institute of Scientific and Technical Information of China (English)

    HU Quan-wei; ZHOU Xing-xing; SI Wen-rong; ZHANG Yang; LI Jur-hao; LI Yan-ming

    2011-01-01

    With the development of power systems,a large number of shunt capacitors are used to improve power quality in the distribution network.The shunt capacitor banks are operated much frequently,as a result,the capacitor banks will bear large numbers of over-voltage inevitably.If the over-voltage exceeds certain amplitude,the capacitor will be damaged.This paper aims at the capacitor banks in the 35 kV side of Shanghai Xu-xing 500 kV substation,and applies ATP-EMTP to simulate the over-voltages generated by operating the switches under different angles of the source.Finally,according to the results of simulation and theoretical analysis,a best choice (i.e.angles of the source) to switch on capacitor banks is proposed.In this case the over-voltage on the capacitor will be limited to lowest.

  17. Laser emission of dye-doped liquid crystal evices under applying voltage%电场作用下染料掺杂液晶器件的激光辐射

    Institute of Scientific and Technical Information of China (English)

    岱钦; 乌日娜; 杨健; 徐送宁; 全薇

    2011-01-01

    通过在向列相液晶TEB30A中掺杂激光染料DCM和手性剂CB15制作了平面排列态液晶器件.采用Nd:YAG倍频532 nm波段激光作为泵浦光源,测量分析了平行于液晶器件表面方向的受激辐射光谱.当泵浦光较弱时,观察到了染料DCM较宽的荧光辐射谱;随着泵浦光的逐渐增强,辐射谱带逐渐变窄,辐射峰中心波长约为610 nm,最小半峰全宽(FWHM)为11 nm.观察了在器件玻璃基板上施加交流电场后激光辐射的变化情况,结果显示,当外加电压<9 V时,辐射强度随着电压的增大逐渐减弱;当外加电压>9 V,辐射强度迅速衰减,谱线变宽,显示了较好的电场控制特性.文章认为这种现象主要是由于电场作用下液晶分子取向发生变化所致.%A planar texture device was prepared by doping a laser dye (DCM) and a chiral compound (CB15) into a nematic liquid crystal TEB30A. By using a second harmonic Q-switched Nd: YAG pulsed laser (λ=532 nm) as pumping source, the emission spectrum of the device surface in the horizontal direction was measured and analyzed. It shows that a wide emission spectrum can be observed when the pump light is weak. With the increase of pump light, the stimulated emission spectrum is narrowed,and its center wavelength with a least Full Width of Half Maximum (FWHM)about 11 nm is at 610 nm. Moreover,by applying a AC voltage along the perpendicular direction to the surface of the device,the laser emission was also observed. When the applying voltage is less than 9 V,the lasing intensity is weakened with the increase of the voltage. When the applying voltage is greater than 9 V,the emission intensity is decreased sharply. These results can be attributed to the liquid crystal alignment changed on the applying electric field.

  18. THE INFLUENCE OF NITROGEN FERTILIZATION APPLIED IN DIFFERENT DOSES ON FODDER QUALITY OF MEADOW SWARD

    Directory of Open Access Journals (Sweden)

    Kazimierz Jankowski

    2013-07-01

    Full Text Available The experiment was organized in four replicants in arrangement split-plot with plots having a surface equal 9 m2. The basic fertilization was applied under the first regrowth. It was a mixture of unary fertilizers (ammonium nitrate, superphosphate, potassic salt or polifoska. One form of supplementary fertilization was applied under the second and third regrowth. It was the stable form of fertilizer applied to soil. This form of supplemented nitrogen gave respectively: 50 kg N·ha-l; 80 kg N·ha-l; 110 kg N·ha-1 per each moving. During the vegetation season three movings were harvested. From each movings the sampIes of green matter were taken for chemical analyses, i.e. total protein content, soluble carbohydrates and net energy (NEL. The obtained results showed large differences in fodder quality of the meadow sward fertilized with three doses of nitrogen.

  19. Effects of Controlled Release Urea on Wheat Yield and Nitrogen Utilization Efficiency Under Different Applied Conditions

    Directory of Open Access Journals (Sweden)

    XIA Wei-guang

    2014-02-01

    Full Text Available The field trial was conducted to study the effects of different nitrogen fertilizer applications on winter wheat yield, nitrogen utilization efficiency and economic benefit. 7 treatments were designed as CK(no nitrogen fertilizer applied, 100%PU10/0(conventional urea applied before sowing, N rate was 240 kg·hm-2, 100%PU6/4(conventional urea applied before sowing and at jointing with the ratio of 6∶4, N rate was 240 kg·hm-2, 80%PU6/4(conventional urea applied before sowing and at jointing with the ratio of 6∶4, N rate was 192 kg·hm-2, 100%CRU(resin coated controlled release urea applied before sowing, N rate was 240 kg·hm-2, 80%CRU(resin coated controlled release urea applied before sowing, N rate was 192 kg·hm-2, and 40%CRU+40%PU(resin coated controlled release urea and conventional urea applied before sowing, N rate was 192 kg·hm-2. The results showed that no matter on the efficiency of yield or that of nitrogen, resin coated controlled-release urea(CRU was better when compared with conventional urea(PU. Especially, the combined application treatment(40%CRU+40%PUwas the best with achieving the highest wheat yield of 7 709 kg·hm-2, the highest N fertilizer utilization efficiency of 36.44% and the maximum net income of 15 946 yuan·hm-2. And it could not only increase winter wheat yield with reducing the nitrogen fertilizer application, but also improve N fertilizer utilization efficiency and owe the highest ratio of output to input. Therefore, the combined application of the resin coated controlled-release urea and conventional urea(40%CRU+40%PUwas the optimal nitrogen fertilizer treatment under the conditions of this experiment.

  20. Diffusion voltage in polymer light emitting diodes measured with electric field induced second harmonic generation

    Energy Technology Data Exchange (ETDEWEB)

    Kristensen, P.K.; Rafaelsen, J.; Pedersen, T.G.; Pedersen, K. [Department of Physics and Nanotechnology, Aalborg University, Pontoppidanstraede 103, 9220 Aalborg East (Denmark)

    2005-12-01

    We apply electric field induced second harmonic (EFISH) to polymer light emitting diodes (PLEDs) and demonstrate the ability to determine the diffusion voltage in PLED devices. The EFISH signal is proportional to the square of the effective field, which is the sum of the diffusion voltage and the applied voltage. By minimizing the EFISH-signal as a function of the applied voltage, the diffusion voltage is determined by measuring the applied voltage that cancels out the diffusion voltage. The PLEDs are fabricated with indium tin oxide (ITO) as the hole injecting contact and two different electron injecting contacts, namely aluminum and calcium. The diffusion voltage originates from the rearranged charges caused by the difference in Fermi levels in the materials in the PLEDs. Different contacts will thus cause different diffusion voltages. We demonstrate here that the EFISH signal is proportional to the square of the effective field in both reverse and forward bias, and discuss the dependence on contact materials. (copyright 2005 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  1. Studying Voltage Transformer Ferroresonance

    Directory of Open Access Journals (Sweden)

    Hamid Radmanesh

    2012-09-01

    Full Text Available This study studies the effect of Circuit Breaker Shunt Resistance (CBSR, Metal Oxide Vaistor (MOV and Neutral earth Resistance (NR on the control of ferroresonance in the voltage transformer. It is expected that NR can controlled ferroresonance better than MOV and CBSR. Study has been done on a one phase voltage transformer rated 100 VA, 275 kV. The simulation results reveal that considering the CBSR and MOV exhibits a great mitigating effect on ferroresonance overvoltages, but these resistances cannot control these phenomena for all range of parameters. By applying NR to the system structure, ferroresonance has been controlled and its amplitude has been damped for all parameters values.

  2. A comparison between different oxide dispersion strengthened ferritic steel ongoing in situ oxide dissolution in High Voltage Electron Microscope

    Energy Technology Data Exchange (ETDEWEB)

    Monnet, I., E-mail: monnet@ganil.fr [Centre de Recherche sur les Ions, les Materiaux et la Photonique, CEA/CNRS/ENSICAEN/UCBN, BP5133-14070 Caen cedex 5 (France); Service de Recherches Metallurgiques Appliquees, CEA/DEN/DMN/SRMA, 91191 Gif sur Yvette cedex (France); Van den Berghe, T.; Dubuisson, Ph. [Service de Recherches Metallurgiques Appliquees, CEA/DEN/DMN/SRMA, 91191 Gif sur Yvette cedex (France)

    2012-05-15

    ODS materials are considered for nuclear applications but previous experimental studies have shown a partial dissolution of some oxides under neutron irradiation. In this work, electron irradiations were used to evaluate the stability of the oxides depending on the chemical composition of the oxide dispersion. Four ferritic steels based on EM10 (Fe-9Cr-1Mo) and reinforced respectively by Al{sub 2}O{sub 3}, MgO, MgAl{sub 2}O{sub 4} and Y{sub 2}O{sub 3}, were studied. These materials were irradiated with 1 MeV or 1.2 MeV electrons in a High Voltage Electron Microscope. This technique allows to follow one single oxide and to determine the evolution of its size during the irradiation. In situ HVEM observations indicate that the dissolution rate depends on the chemical composition of the oxide, on the temperature and on the irradiation dose.

  3. Novel Low Loss Active Voltage Clamp Circuit for Series Connection of RCGCT thyristors

    Science.gov (United States)

    Ito, Hiroshi; Suzuki, Akihiro; Iwata, Akihiko

    This paper describes novel low loss active voltage clamp circuits for the series connection of RCGCT thyristors. For high voltage converters the series connection of power semiconductor devices is an essential technique for direct switching of high voltages. Several protection circuits have been applied to the series connection of RCGCT thyristors such as CRD snubber circuits which suppress over-voltages across RCGCT thyristors, and voltage balancing resistors to equalize voltage sharing in steady states. However, significant losses in these protection circuits lower the converter’s efficiency. We propose novel low-loss protection circuits, which have active voltage clamp snubber circuits and static voltage balancing circuits. The clamp capacitor voltage of the active voltage clamp snubber circuits are designed to be higher than the equally divided DC-Link voltage. This method can reduce the loss of the clamp circuit to no more than 1/10 of that of the conventional CRD snubber. Also the static voltage balancing circuits compensate for the voltage imbalance generated by the difference in the leakage current between the series connection RCGCT thyristors.

  4. Steganography Algorithm in Different Colour Model Using an Energy Adjustment Applied with Discrete Wavelet Transform

    Directory of Open Access Journals (Sweden)

    Carvajal-Gamez

    2012-09-01

    Full Text Available When color images are processed in different color model for implementing steganographic algorithms, is important to study the quality of the host and retrieved images, since it is typically used digital filters, visibly reaching deformed images. Using a steganographic algorithm, numerical calculations performed by the computer cause errors and alterations in the test images, so we apply a proposed scaling factor depending on the number of bits of the image to adjust these errors.

  5. Steganography Algorithm in Different Colour Model Using an Energy Adjustment Applied with Discrete Wavelet Transform

    Directory of Open Access Journals (Sweden)

    B.E. Carvajal-Gámez

    2012-08-01

    Full Text Available When color images are processed in different color model for implementing steganographic algorithms, is important to study the quality of the host and retrieved images, since it is typically used digital filters, visibly reaching deformed images. Using a steganographic algorithm, numerical calculations performed by the computer cause errors and alterations in the test images, so we apply a proposed scaling factor depending on the number of bits of the image to adjust these errors.

  6. Independent comparison study of six different electronic tongues applied for pharmaceutical analysis.

    Science.gov (United States)

    Pein, Miriam; Kirsanov, Dmitry; Ciosek, Patrycja; del Valle, Manel; Yaroshenko, Irina; Wesoły, Małgorzata; Zabadaj, Marcin; Gonzalez-Calabuig, Andreu; Wróblewski, Wojciech; Legin, Andrey

    2015-10-10

    Electronic tongue technology based on arrays of cross-sensitive chemical sensors and chemometric data processing has attracted a lot of researchers' attention through the last years. Several so far reported applications dealing with pharmaceutical related tasks employed different e-tongue systems to address different objectives. In this situation, it is hard to judge on the benefits and drawbacks of particular e-tongue implementations for R&D in pharmaceutics. The objective of this study was to compare the performance of six different e-tongues applied to the same set of pharmaceutical samples. For this purpose, two commercially available systems (from Insent and AlphaMOS) and four laboratory prototype systems (two potentiometric systems from Warsaw operating in flow and static modes, one potentiometric system from St. Petersburg, one voltammetric system from Barcelona) were employed. The sample set addressed in the study comprised nine different formulations based on caffeine citrate, lactose monohydrate, maltodextrine, saccharin sodium and citric acid in various combinations. To provide for the fair and unbiased comparison, samples were evaluated under blind conditions and data processing from all the systems was performed in a uniform way. Different mathematical methods were applied to judge on similarity of the e-tongues response from the samples. These were principal component analysis (PCA), RV' matrix correlation coefficients and Tuckeŕs congruency coefficients.

  7. The comparisons on total RNA from different source-original neurons applied in LMPC

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    Objective To compare the quality and quantity of total RNA from different source-original neurons applied in LMPC technique. Methods (1) Aglient 2100 bioanalyzer and RT-PCR were used to check the concentration and fragmentation of total RNA from unfixed, temporal fixed and fixed 12 h hypothalamus sections; (2)Different neurons of PVN and SON were collected by LMPC, CRH, TRH, AVP, OT mRNA level were measured by RT-PCR; (3)Labeled neurons by injecting CTB into stomach and non-labeled neurons in DMV collected by LMPC were checked for house keeping genes by RT-PCR. Results ( 1 ) Unfixed section had higher concentration and better quality of total RNA compared with fixed sections applied in LMPC; relative short amplicons such as GAPDH, NSE, MCH and MC4R were successfully obtained from fixed and unfixed and long amplicon of GR can only be obtained from unfixed material; (2) In magnocellular PVN and SON the expressions of AVP and OT were more special than those in the parvocellular PVN. Oppositely, the expressions of CRH, TRH in the parvocellular were more special than the other two; (3) The expressions of house keeping genes had no significant difference between labeled and non-labeled DMV neurons. Conclusion The quality and quantity of total RNA from unfixed brain tissues were better than fixed tissues applied in LMPC and the CTB tracer which may differentiate neurons had no significant effect on physiology of the neurons applied in LMPC. The results showed that the LMPC technique is suitable for the qualitative and quantitative study on individual neurons at mRNA level.

  8. Different variants of R13 moment equations applied to the shock-wave structure

    Science.gov (United States)

    Timokhin, M. Yu.; Struchtrup, H.; Kokhanchik, A. A.; Bondar, Ye. A.

    2017-03-01

    Various versions of the regularized 13-moment system (R13) are applied to the problem of the shock wave structure in a monatomic Maxwell gas for Mach numbers up to M = 10. Numerical solutions are compared to direct simulation Monte Carlo results computed by the SMILE++ software system, in order to identify applicability and limitations of the variants. Over time, several versions of the R13 equations were presented, which differ in non-linear contributions for high-order moments but agree in asymptotic expansion to the third order in the Knudsen number. All variants describe typical subsonic microflows well, for which the non-linear contributions only play a minor role. The challenge of the present study is to determine the real boundaries of applicability of each variant of the moment equations as applied to non-equilibrium supersonic flows, depending on the Mach number and local Knudsen number.

  9. Mechanisms of Inactivation by High-Voltage Atmospheric Cold Plasma Differ for Escherichia coli and Staphylococcus aureus.

    Science.gov (United States)

    Han, L; Patil, S; Boehm, D; Milosavljević, V; Cullen, P J; Bourke, P

    2016-01-01

    Atmospheric cold plasma (ACP) is a promising nonthermal technology effective against a wide range of pathogenic microorganisms. Reactive oxygen species (ROS) play a crucial inactivation role when air or other oxygen-containing gases are used. With strong oxidative stress, cells can be damaged by lipid peroxidation, enzyme inactivation, and DNA cleavage. Identification of ROS and an understanding of their role are important for advancing ACP applications for a range of complex microbiological issues. In this study, the inactivation efficacy of in-package high-voltage (80 kV [root mean square]) ACP (HVACP) and the role of intracellular ROS were investigated. Two mechanisms of inactivation were observed in which reactive species were found to either react primarily with the cell envelope or damage intracellular components. Escherichia coli was inactivated mainly by cell leakage and low-level DNA damage. Conversely, Staphylococcus aureus was mainly inactivated by intracellular damage, with significantly higher levels of intracellular ROS observed and little envelope damage. However, for both bacteria studied, increasing treatment time had a positive effect on the intracellular ROS levels generated.

  10. Effect of three different irrigation solutions applied by passive ultrasonic irrigation

    Directory of Open Access Journals (Sweden)

    Carmen Llena

    2015-05-01

    Full Text Available Objectives This study evaluated the maximum depth and percentage of irrigant penetration into dentinal tubules by passive ultrasonic irrigation (PUI. Materials and Methods Thirty extracted human teeth were instrumented and divided into three groups. According to final irrigation regimen, 5.25% sodium hypochlorite (Group A, NaOCl, 2% chlorhexidine (Group B, CHX and saline solution (Group C, control group were applied with Irrisafe 20 tips (Acteon and PUI. Irrigant was mixed with 0.1% rhodamine B. Sections at 2 mm, 5 mm, and 8 mm from the apex were examined with confocal laser scanning microscopy (CLSM. The percentage and maximum depth of irrigant penetration were measured. Kruskal-Wallis test and Mann-Whitney test were performed for overall comparison between groups at each level and for pairwise comparison, respectively. Within a group, Wilcoxon test was performed among different levels. p values less than 0.05 were considered significant. Results In all groups, highest penetration depth and percentage of penetration were observed at the 8 mm level. At 2 mm level, Groups A and B had significantly greater depths and percentages in penetration than Group C (p < 0.05, but there were no significant differences between Groups A and B. At 5 mm level, penetration depths and percentage of penetration was not significantly different among the groups. Conclusions NaOCl and CHX applied by PUI showed similar depth and percentage of penetration at all evaluated levels.

  11. Voltage Swells Improvement in Low Voltage Network Using Dynamic Voltage Restorer

    Directory of Open Access Journals (Sweden)

    R. Omar

    2011-01-01

    Full Text Available Problem statement: Voltage disturbances are the most common power quality problem due to the increased use of a large numbers of sophisticated electronic equipment in industrial distribution system. The voltage disturbances such as voltage sags, swells, harmonics, unbalance and flickers. High quality in the power supply is needed, since failures due to such disturbances usually have a high impact on production cost. There are many different solutions to compensate voltage disturbances but the use of a DVR is considered to be the most cost effective method. The objective of this study is to propose a new topology of a DVR in order to mitigate voltage swells using a powerful power custom device namely the Dynamic Voltage Restorer (DVR. Approach: New configuration of a DVR with an improvement of a controller based on direct-quadrature-zero method has been introduced to compensate voltage swells in the network. Results: The effectiveness of the DVR with its controller were verify using Matlab/Simulinks SimPower Toolbox and then implemented using 5KVA DVR experimental setup. Simulations and experimental results demonstrate the effective dynamic performance of the proposed configuration. Conclusion: The implimentation of the proposed DVR validate the capabilities in mitigating of voltage swells effectiveness.During voltage swells, the DVR injects an appropriate voltage to maintain the load voltage at its nominal value.

  12. Computational modeling of voltage-gated Ca channels inhibition: identification of different effects on uterine and cardiac action potentials

    Directory of Open Access Journals (Sweden)

    Wing Chiu eTong

    2014-10-01

    Full Text Available The uterus and heart share the important physiological feature whereby contractile activation of the muscle tissue is regulated by the generation of periodic, spontaneous electrical action potentials (APs. Preterm birth arising from premature uterine contractions is a major complication of pregnancy and there remains a need to pursue avenues of research that facilitate the use of drugs, tocolytics, to limit these inappropriate contractions without deleterious actions on cardiac electrical excitation. A novel approach is to make use of mathematical models of uterine and cardiac APs, which incorporate many ionic currents contributing to the AP forms, and test the cell-specific responses to interventions. We have used three such models – of uterine smooth muscle cells (USMC, cardiac sinoatrial node cells (SAN and ventricular cells – to investigate the relative effects of reducing two important voltage-gated Ca currents – the L-type (ICaL and T-type (ICaT Ca currents. Reduction of ICaL (10% alone, or ICaT (40% alone, blunted USMC APs with little effect on ventricular APs and only mild effects on SAN activity. Larger reductions in either current further attenuated the USMC APs but with also greater effects on SAN APs. Encouragingly, a combination of ICaL and ICaT reduction did blunt USMC APs as intended with little detriment to APs of either cardiac cell type. Subsequent overlapping maps of ICaL and ICaT inhibition profiles from each model revealed a range of combined reductions of ICaL and ICaT over which an appreciable diminution of USMC APs could be achieved with no deleterious action on cardiac SAN or ventricular APs. This novel approach illustrates the potential for computational biology to inform us of possible uterine and cardiac cell-specific mechanisms. Incorporating such computational approaches in future studies directed at designing new, or repurposing existing, tocolytics will be beneficial for establishing a desired uterine

  13. Characteristics of couples applying for bibliotherapy via different recruitment strategies: a multivariate comparison.

    Science.gov (United States)

    van Lankveld, J J; Grotjohann, Y; van Lokven, B M; Everaerd, W

    1999-01-01

    This study compared characteristics of couples with different sexual dysfunctions who were recruited for participation in a bibliotherapy program via two routes: in response to media advertisements and through their presence on a waiting list for therapist-administered treatment in an outpatient sexology clinic. Data were collected from 492 subjects (246 couples). Male sexology patients were younger than media-recruited males. However, type of sexual dysfunction accounted for a substantially larger proportion of variance in the demographic and psychometric data. An interaction effect of recruitment strategy and sexual dysfunction type was found with respect to female anorgasmia. We conclude from the absence of differences between the two study groups that the Wills and DePaulo (1991) model of help-seeking behavior for mental problems does not apply to couples with sexual dysfunctions joining a bibliotherapy program who either primarily requested professional treatment or who responded to media advertising.

  14. Different thermostabilities of FLP and Cre recombinases: implications for applied site-specific recombination.

    Science.gov (United States)

    Buchholz, F; Ringrose, L; Angrand, P O; Rossi, F; Stewart, A F

    1996-11-01

    Genomic manipulations using site-specific recombinases rely on their applied characteristics in living systems. To understand their applied properties so that they can be optimally deployed, we compared the recombinases FLP and Cre in two assays. In both Escherichia coli and in vitro, FLP shows a different temperature optimum than Cre. FLP is more thermolabile, having an optimum near 30 degrees C and little detectable activity above 39 degrees C. Cre is optimally efficient at 37 degrees C and above. Consistent with FLP thermolability, recombination in a mammalian cell line mediated by a ligand- regulated FLP-androgen receptor fusion protein is more efficient at 35 degrees C than at higher temperatures. We also document a mutation in a commercially available FLP plasmid (FLP-F70L) which renders this recombinase even more thermolabile. The different temperature optima of FLP, FLP-F70L and Cre influence their strategies of usage. Our results recommend the use of Cre for applications in mice that require efficient recombination. The thermolabilities of FLP and FLP-F70L can be usefully exploited for gain of function and cell culture applications.

  15. Defect production in Ar irradiated graphene membranes under different initial applied strains

    Energy Technology Data Exchange (ETDEWEB)

    Martinez-Asencio, J., E-mail: jesusmartinez@ua.es [Dept. Física Aplicada, Facultad de Ciencias, Fase II, Universidad de Alicante, Alicante E-036090 (Spain); Ruestes, C.J.; Bringa, E. [CONICET and Facultad de Ciencias Exactas y Naturales, Universidad Nacional de Cuyo, Mendoza 5500 (Argentina); Caturla, M.J. [Dept. Física Aplicada, Facultad de Ciencias, Fase II, Universidad de Alicante, Alicante E-036090 (Spain)

    2017-02-15

    Highlights: • Defects in graphene membranes are formed due to 140 eV Ar ions irradiation using MD. • Different initial strains are applied, which influence the type and number of defects. • Mono-vacancies, di-vacancies and tri-vacancies production behaves linearly with dose. • The total number of defects under compression is slightly higher than under tension. - Abstract: Irradiation with low energy Ar ions of graphene membranes gives rise to changes in the mechanical properties of this material. These changes have been associated to the production of defects, mostly isolated vacancies. However, the initial state of the graphene membrane can also affect its mechanical response. Using molecular dynamics simulations we have studied defect production in graphene membranes irradiated with 140 eV Ar ions up to a dose of 0.075 × 10{sup 14} ions/cm{sup 2} and different initial strains, from −0.25% (compressive strain) to 0.25% (tensile strain). For all strains, the number of defects increases linearly with dose with a defect production of about 80% (80 defects every 100 ions). Defects are mostly single vacancies and di-vacancies, although some higher order clusters are also observed. Two different types of di-vacancies have been identified, the most common one being two vacancies at first nearest neighbours distance. Differences in the total number of defects with the applied strain are observed which is related to the production of a higher number of di-vacancies under compressive strain compared to tensile strain. We attribute this effect to the larger out-of-plane deformations of compressed samples that could favor the production of defects in closer proximity to others.

  16. Output voltage calculations in double barrier magnetic tunnel junctions with asymmetric voltage behavior

    KAUST Repository

    Useinov, Arthur

    2011-10-22

    In this paper we study the asymmetric voltage behavior (AVB) of the tunnel magnetoresistance (TMR) for single and double barrier magnetic tunnel junctions (MTJs) in range of a quasi-classical free electron model. Numerical calculations of the TMR-V curves, output voltages and I-V characteristics for negative and positive values of applied voltages were carried out using MTJs with CoFeB/MgO interfaces as an example. Asymmetry of the experimental TMR-V curves is explained by different values of the minority and majority Fermi wave vectors for the left and right sides of the tunnel barrier, which arises due to different annealing regimes. Electron tunneling in DMTJs was simulated in two ways: (i) Coherent tunneling, where the DMTJ is modeled as one tunnel system and (ii) consecutive tunneling, where the DMTJ is modeled by two single barrier junctions connected in series. © 2012 Elsevier B.V. All rights reserved.

  17. Accurate Switched-Voltage voltage averaging circuit

    OpenAIRE

    金光, 一幸; 松本, 寛樹

    2006-01-01

    Abstract ###This paper proposes an accurate Switched-Voltage (SV) voltage averaging circuit. It is presented ###to compensated for NMOS missmatch error at MOS differential type voltage averaging circuit. ###The proposed circuit consists of a voltage averaging and a SV sample/hold (S/H) circuit. It can ###operate using nonoverlapping three phase clocks. Performance of this circuit is verified by PSpice ###simulations.

  18. Signal enhancement in collinear double-pulse laser-induced breakdown spectroscopy applied to different soils

    Energy Technology Data Exchange (ETDEWEB)

    Nicolodelli, Gustavo, E-mail: gunicolodelli@hotmail.com [Embrapa Instrumentation, Rua XV de Novembro, 1452, CEP 13560-970 São Carlos, SP (Brazil); Senesi, Giorgio Saverio, E-mail: giorgio.senesi@imip.cnr.it [Institute of Inorganic Methodologies and Plasmas, CNR, Bari, 70126 Bari (Italy); Romano, Renan Arnon, E-mail: renan.romano@gmail.com [Embrapa Instrumentation, Rua XV de Novembro, 1452, CEP 13560-970 São Carlos, SP (Brazil); Physics Institute of São Carlos, University of São Paulo, IFSC-USP, Av. Trabalhador são-carlense, 400 Pq. Arnold Schimid, 13566-590 São Carlos, SP (Brazil); Oliveira Perazzoli, Ivan Luiz de, E-mail: ivanperazzoli@hotmail.com [Embrapa Instrumentation, Rua XV de Novembro, 1452, CEP 13560-970 São Carlos, SP (Brazil); Milori, Débora Marcondes Bastos Pereira, E-mail: debora.milori@embrapa.br [Embrapa Instrumentation, Rua XV de Novembro, 1452, CEP 13560-970 São Carlos, SP (Brazil)

    2015-09-01

    Laser-induced breakdown spectroscopy (LIBS) is a well-known consolidated analytical technique employed successfully for the qualitative and quantitative analysis of solid, liquid, gaseous and aerosol samples of very different nature and origin. Several techniques, such as dual-pulse excitation setup, have been used in order to improve LIBS's sensitivity. The purpose of this paper was to optimize the key parameters as excitation wavelength, delay time and interpulse, that influence the double pulse (DP) LIBS technique in the collinear beam geometry when applied to the analysis at atmospheric air pressure of soil samples of different origin and texture from extreme regions of Brazil. Additionally, a comparative study between conventional single pulse (SP) LIBS and DP LIBS was performed. An optimization of DP LIBS system, choosing the correct delay time between the two pulses, was performed allowing its use for different soil types and the use of different emission lines. In general, the collinear DP LIBS system improved the analytical performances of the technique by enhancing the intensity of emission lines of some elements up to about 5 times, when compared with conventional SP-LIBS, and reduced the continuum emission. Further, the IR laser provided the best performance in re-heating the plasma. - Highlights: • The correct choice of the delay time between the two pulses is crucial for the DP system. • An optimization of DP LIBS system was performed allowing its use for different soil and the use of different emission lines. • The DP LIBS system improved the analytical performances of the technique up to about 5 times, when compared with SP LIBS. • The IR laser provided the best performance in re-heating the plasma.

  19. Applying different independent component analysis algorithms and support vector regression for IT chain store sales forecasting.

    Science.gov (United States)

    Dai, Wensheng; Wu, Jui-Yu; Lu, Chi-Jie

    2014-01-01

    Sales forecasting is one of the most important issues in managing information technology (IT) chain store sales since an IT chain store has many branches. Integrating feature extraction method and prediction tool, such as support vector regression (SVR), is a useful method for constructing an effective sales forecasting scheme. Independent component analysis (ICA) is a novel feature extraction technique and has been widely applied to deal with various forecasting problems. But, up to now, only the basic ICA method (i.e., temporal ICA model) was applied to sale forecasting problem. In this paper, we utilize three different ICA methods including spatial ICA (sICA), temporal ICA (tICA), and spatiotemporal ICA (stICA) to extract features from the sales data and compare their performance in sales forecasting of IT chain store. Experimental results from a real sales data show that the sales forecasting scheme by integrating stICA and SVR outperforms the comparison models in terms of forecasting error. The stICA is a promising tool for extracting effective features from branch sales data and the extracted features can improve the prediction performance of SVR for sales forecasting.

  20. Applying Different Independent Component Analysis Algorithms and Support Vector Regression for IT Chain Store Sales Forecasting

    Directory of Open Access Journals (Sweden)

    Wensheng Dai

    2014-01-01

    Full Text Available Sales forecasting is one of the most important issues in managing information technology (IT chain store sales since an IT chain store has many branches. Integrating feature extraction method and prediction tool, such as support vector regression (SVR, is a useful method for constructing an effective sales forecasting scheme. Independent component analysis (ICA is a novel feature extraction technique and has been widely applied to deal with various forecasting problems. But, up to now, only the basic ICA method (i.e., temporal ICA model was applied to sale forecasting problem. In this paper, we utilize three different ICA methods including spatial ICA (sICA, temporal ICA (tICA, and spatiotemporal ICA (stICA to extract features from the sales data and compare their performance in sales forecasting of IT chain store. Experimental results from a real sales data show that the sales forecasting scheme by integrating stICA and SVR outperforms the comparison models in terms of forecasting error. The stICA is a promising tool for extracting effective features from branch sales data and the extracted features can improve the prediction performance of SVR for sales forecasting.

  1. The N-Terminal Peptides of the Three Human Isoforms of the Mitochondrial Voltage-Dependent Anion Channel Have Different Helical Propensities.

    Science.gov (United States)

    Guardiani, Carlo; Scorciapino, Mariano Andrea; Amodeo, Giuseppe Federico; Grdadolnik, Joze; Pappalardo, Giuseppe; De Pinto, Vito; Ceccarelli, Matteo; Casu, Mariano

    2015-09-15

    The voltage-dependent anion channel (VDAC) is the main mitochondrial porin allowing the exchange of ions and metabolites between the cytosol and the mitochondrion. In addition, VDAC was found to actively interact with proteins playing a fundamental role in the regulation of apoptosis and being of central interest in cancer research. VDAC is a large transmembrane β-barrel channel, whose N-terminal helical fragment adheres to the channel interior, partially closing the pore. This fragment is considered to play a key role in protein stability and function as well as in the interaction with apoptosis-related proteins. Three VDAC isoforms are differently expressed in higher eukaryotes, for which distinct and complementary roles are proposed. In this work, the folding propensity of their N-terminal fragments has been compared. By using multiple spectroscopic techniques, and complementing the experimental results with theoretical computer-assisted approaches, we have characterized their conformational equilibrium. Significant differences were found in the intrinsic helical propensity of the three peptides, decreasing in the following order: hVDAC2 > hVDAC3 > hVDAC1. In light of the models proposed in the literature to explain voltage gating, selectivity, and permeability, as well as interactions with functionally related proteins, our results suggest that the different chemicophysical properties of the N-terminal domain are possibly correlated to different functions for the three isoforms. The overall emerging picture is that a similar transmembrane water accessible conduit has been equipped with not identical domains, whose differences can modulate the functional roles of the three VDAC isoforms.

  2. Alternating current breakdown voltage of ice electret

    Science.gov (United States)

    Oshika, Y.; Tsuchiya, Y.; Okumura, T.; Muramoto, Y.

    2017-09-01

    Ice has low environmental impact. Our research objectives are to study the availability of ice as a dielectric insulating material at cryogenic temperatures. We focus on ferroelectric ice (iceXI) at cryogenic temperatures. The properties of iceXI, including its formation, are not clear. We attempted to obtain the polarized ice that was similar to iceXI under the applied voltage and cooling to 77 K. The polarized ice have a wide range of engineering applications as electronic materials at cryogenic temperatures. This polarized ice is called ice electret. The structural difference between ice electret and normal ice is only the positions of protons. The effects of the proton arrangement on the breakdown voltage of ice electret were shown because electrical properties are influenced by the structure of ice. We observed an alternating current (ac) breakdown voltage of ice electret and normal ice at 77 K. The mean and minimum ac breakdown voltage values of ice electret were higher than those of normal ice. We considered that the electrically weak part of the normal ice was improved by applied a direct electric field.

  3. Biot Critical Frequency Applied as Common Friction Factor for Chalk with Different Pore Fluids and Temperatures

    DEFF Research Database (Denmark)

    Andreassen, Katrine Alling; Fabricius, Ida Lykke

    2010-01-01

    and we propose that the fluid effect on mechanical properties of highly porous chalk may be the result of liquid‐solid friction. Applying a different strain or stress rate is influencing the rock strength and needs to be included. The resulting function is shown to relate to the material dependent...... and rate independent b-factor used when describing the time dependent mechanical properties of soft rock or soils. As a consequence it is then possible to further characterize the material constant from the porosity and permeability of the rock as well as from pore fluid density and viscosity which......Injection of water into chalk hydrocarbon reservoirs has lead to mechanical yield and failure. Laboratory experiments on chalk samples correspondingly show that the mechanical properties of porous chalk depend on pore fluid and temperature. Water has a significant softening effect on elastic...

  4. Comparative studies for different proximity potentials applied to sub-barrier fusion reactions

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, G.L. [Beihang University, School of Physics and Nuclear Energy Engineering, Beijing (China); Beihang University, Key Laboratory of Micro-Nano Measurement-Manipulation and Physics (Ministry of Education), Beijing (China); Qu, W.W. [Medical College of Soochow University, School of Radiation Medicine and Protection, Soochow (China); Guo, M.F.; Qian, J.Q. [Beihang University, School of Physics and Nuclear Energy Engineering, Beijing (China); Zhang, H.Q. [China Institute of Atomic Energy, Beijing (China); Wolski, R. [Henryk Niewodniczanski Institute of Nuclear Physics PAS, Cracow (Poland)

    2016-02-15

    Coulomb barrier heights calculated by using 14 different versions of proximity potentials are studied and applied for experimental data of fusion in terms of a recently proposed energy scaling approach. The results show that the descriptions of proximity potentials 77 and 88 for the barrier heights seem to be closest to the values required by the systematics. On the basis of proximity potential 77, the parameterized formulas of the barrier height and radius are obtained. These formulas can calculate the barrier positions and barrier heights reasonably well within the error, respectively. Thus it provides a simple and direct way to calculate the barrier positions and barrier heights for heavy-ion fusion reactions. (orig.)

  5. Biot Critical Frequency Applied as Common Friction Factor for Chalk with Different Pore Fluids and Temperatures

    DEFF Research Database (Denmark)

    Andreassen, Katrine Alling; Fabricius, Ida Lykke

    2010-01-01

    Injection of water into chalk hydrocarbon reservoirs has lead to mechanical yield and failure. Laboratory experiments on chalk samples correspondingly show that the mechanical properties of porous chalk depend on pore fluid and temperature. Water has a significant softening effect on elastic...... and we propose that the fluid effect on mechanical properties of highly porous chalk may be the result of liquid‐solid friction. Applying a different strain or stress rate is influencing the rock strength and needs to be included. The resulting function is shown to relate to the material dependent...... and rate independent b-factor used when describing the time dependent mechanical properties of soft rock or soils. As a consequence it is then possible to further characterize the material constant from the porosity and permeability of the rock as well as from pore fluid density and viscosity which...

  6. TiO2 Nanosols Applied Directly on Textiles Using Different Purification Treatments

    Directory of Open Access Journals (Sweden)

    Simona Ortelli

    2015-11-01

    Full Text Available Self-cleaning applications using TiO2 coatings on various supporting media have been attracting increasing interest in recent years. This work discusses the issue of self-cleaning textile production on an industrial scale. A method for producing self-cleaning textiles starting from a commercial colloidal nanosuspension (nanosol of TiO2 is described. Three different treatments were developed for purifying and neutralizing the commercial TiO2 nanosol: washing by ultrafiltration; purifying with an anion exchange resin; and neutralizing in an aqueous solution of ammonium bicarbonate. The different purified TiO2 nanosols were characterized in terms of particle size distribution (using dynamic light scattering, electrical conductivity, and ζ potential (using electrophoretic light scattering. The TiO2-coated textiles’ functional properties were judged on their photodegradation of rhodamine B (RhB, used as a stain model. The photocatalytic performance of the differently treated TiO2-coated textiles was compared, revealing the advantages of purification with an anion exchange resin. The study demonstrated the feasibility of applying commercial TiO2 nanosol directly on textile surfaces, overcoming problems of existing methods that limit the industrial scalability of the process.

  7. Applying different equations to evaluate the level of mismatch between students and school furniture.

    Science.gov (United States)

    Castellucci, H I; Arezes, P M; Molenbroek, J F M

    2014-07-01

    The mismatch between students and school furniture is likely to result in a number of negative effects, such as uncomfortable body posture, pain, and ultimately, it may also affect the learning process. This study's main aim is to review the literature describing the criteria equations for defining the mismatch between students and school furniture, to apply these equations to a specific sample and, based on the results, to propose a methodology to evaluate school furniture suitability. The literature review comprises one publications database, which was used to identify the studies carried out in the field of the abovementioned mismatch. The sample used for testing the different equations was composed of 2261 volunteer subjects from 14 schools. Fifteen studies were found to meet the criteria of this review and 21 equations to test 6 furniture dimensions were identified. Regarding seat height, there are considerable differences between the two most frequently used equations. Although seat to desk clearance was evaluated by knee height, this condition seems to be based on the false assumption that students are sitting on a chair with a proper seat height. Finally, the proposed methodology for suitability evaluation of school furniture should allow for a more reliable analysis of school furniture.

  8. The effect of applying different water levels and irrigation frequencies in propagating rosemary (Rosmarinus officinalis L.

    Directory of Open Access Journals (Sweden)

    Javier Giovanni Álvarez Herrera

    2010-05-01

    Full Text Available Rosemary seedlings are obtained by vegetative propagation because the seeds present low viability. Despite being an expanding crop, there is little information on water consumption during the propagation stage. Water levels and irrigation frequencies were therefore applied using a completely randomised design having a 4 x 2 factorial arrangement. The first factor concerned irrigation frequency (4 and 8 days and the second concerned water level (0.6, 0.8, 1.0 and 1.2 evaporation inside the greenhouse. A 1.0 coefficient combined with 4-day irrigation frequency presented the best results regarding height (39.3 cm, fresh weight, dry weight and branch length (146 cm. Water level affected the fresh and dry weight of leaves regardless of frequency. Relative water content in leaves did not present differences due to environmental conditions minimising treatment effect. Rooting percent- tage showed no significant differences regarding irrigation frequency or water level. Irrigation frequency did not affect rosemary growing pattern because sphagnum retains high moisture content. The best branch number (34 was obtained with 1.0 coefficient and 4-day frequency, this being important from the production point of view because this is the material which is sold. Water management changes photoassimilate distribution in rosemary plants.

  9. Songbirds and humans apply different strategies in a sound sequence discrimination task

    Directory of Open Access Journals (Sweden)

    Yoshimasa eSeki

    2013-07-01

    Full Text Available The abilities of animals and humans to extract rules from sound sequences have previously been compared using observation of spontaneous responses and conditioning techniques. However, the results were inconsistently interpreted across studies possibly due to methodological and/or species differences. Therefore, we examined the strategies for discrimination of sound sequences in Bengalese finches and humans using the same protocol. Birds were trained on a GO/NOGO task to discriminate between two categories of sound stimulus generated based on an AAB or ABB rule. The sound elements used were taken from a variety of male (M and female (F calls, such that the sequences could be represented as MMF and MFF. In test sessions, FFM and FMM sequences, which were never presented in the training sessions but conformed to the rule, were presented as probe stimuli. The results suggested two discriminative strategies were being applied: 1 memorizing sound patterns of either GO or NOGO stimuli and generating the appropriate responses for only those sounds; and 2 using the repeated element as a cue. There was no evidence that the birds successfully extracted the abstract rule (i.e. AAB and ABB; MMF-GO subjects did not produce a GO response for FFM and vice versa. Next we examined whether those strategies were also applicable for human participants on the same task. The results and questionnaires revealed that participants extracted the abstract rule, and most of them employed it to discriminate the sequences. This strategy was never observed in bird subjects, although some participants used strategies similar to the birds when responding to the probe stimuli. Our results showed that the human participants applied the abstract rule in the task even without instruction but Bengalese finches did not, thereby reconfirming that humans have to extract abstract rules from sound sequences that is distinct from non-human animals.

  10. The Effect of Carbon Dioxide Insufflation Applied at Different Pressures and Periods on Thrombotic Factors.

    Science.gov (United States)

    Sen, Mehmet Celal; Turkyilmaz, Zafer; Sonmez, Kaan; Karabulut, Ramazan; Kaya, Zuhre; Yenicesu, Idil; Gursel, Turkiz; Basaklar, Abdullah Can

    2016-03-01

    The aim of this experimantal study which is applied on rats, is to determine the differences on the clotting factors over the application of low and high intraabdominal pressure (IAP) values in different periods of time in carbon dioxide (CO2) pneumoperitoneum. Thirty rats were randomized into five groups (n = 6): a control group (Group K) and 1 h and 6 mm Hg IAP (Group A), 2 h and 6 mm Hg IAP (Group B), 1 h and 12 mm Hg IAP (Group C) and 2 h and 12 mm Hg IAP were created with CO2 pneumoperitoneum (Group D). At the end of the experiment, plasma samples taken from subjects and fibrinogen, FII (prothrombin), FV, FVII, FVIII, FIX, FX, FXI, FXII, von willebrand's factor (vWF), ristocetin cofactor, protein C, protein S, antithrombin III (AT III) levels are studied. There were statistically significant differences in the mean levels of FII, FV, FVII, FVIII, FIX, FX, FXI, FXII, and protein S between the groups. A hypercoagulable state occurred with the following: increase in the coagulation parameters compared to the control group; increase in FVII in the group only Group C; decrease in AT III in all groups compared to the control group; decrease in protein C in the group only XII Group D compared to control group; decrease in protein S in all groups except group D compared to control group. CO2 insufflation predisposes to thromboembolic events both by inducing coagulation factors and by suppressing the fibrinolytic system contrary to the controversies in the literature.

  11. A study of the effect on human mesenchymal stem cells of an atmospheric pressure plasma source driven by different voltage waveforms

    Science.gov (United States)

    Laurita, R.; Alviano, F.; Marchionni, C.; Abruzzo, P. M.; Bolotta, A.; Bonsi, L.; Colombo, V.; Gherardi, M.; Liguori, A.; Ricci, F.; Rossi, M.; Stancampiano, A.; Tazzari, P. L.; Marini, M.

    2016-09-01

    The effect of an atmospheric pressure non-equilibrium plasma on human mesenchymal stem cells was investigated. A dielectric barrier discharge non-equilibrium plasma source driven by two different high-voltage pulsed generators was used and cell survival, senescence, proliferation, and differentiation were evaluated. Cells deprived of the culture medium and treated with nanosecond pulsed plasma showed a higher mortality rate, while higher survival and retention of proliferation were observed in cells treated with microsecond pulsed plasma in the presence of the culture medium. While a few treated cells showed the hallmarks of senescence, unexpected delayed apoptosis ensued in cells exposed to plasma-treated medium. The plasma treatment did not change the expression of OCT4, a marker of mesenchymal stem cell differentiation.

  12. Research and Experiments on a Unipolar Capacitive Voltage Sensor

    Directory of Open Access Journals (Sweden)

    Qiang Zhou

    2015-08-01

    Full Text Available Voltage sensors are an important part of the electric system. In service, traditional voltage sensors need to directly contact a high-voltage charged body. Sensors involve a large volume, complex insulation structures, and high design costs. Typically an iron core structure is adopted. As a result, ferromagnetic resonance can occur easily during practical application. Moreover, owing to the multilevel capacitor divider, the sensor cannot reflect the changes of measured voltage in time. Based on the electric field coupling principle, this paper designs a new voltage sensor; the unipolar structure design solves many problems of traditional voltage sensors like the great insulation design difficulty and high costs caused by grounding electrodes. A differential signal input structure is adopted for the detection circuit, which effectively restrains the influence of the common-mode interference signal. Through sensor modeling, simulation and calculations, the structural design of the sensor electrode was optimized, miniaturization of the sensor was realized, the voltage division ratio of the sensor was enhanced, and the phase difference of sensor measurement was weakened. The voltage sensor is applied to a single-phase voltage class line of 10 kV for testing. According to the test results, the designed sensor is able to meet the requirements of accurate and real-time measurement for voltage of the charged conductor as well as to provide a new method for electricity larceny prevention and on-line monitoring of the power grid in an electric system. Therefore, it can satisfy the development demands of the smart power grid.

  13. Heart Rate assessment by means of a novel approach applied to signals of different nature

    Science.gov (United States)

    Cosoli, G.; Casacanditella, L.; Tomasini, EP; Scalise, L.

    2017-01-01

    Electrocardiographic (ECG) signal presents many clinically relevant features (e.g. QT-interval, that is the duration of the ventricular depolarization). A novel processing technique has been demonstrated to be capable to measure some important characteristics according to the morphology of the waveform. Basing on that, the aim of this work is to propose an improved algorithm and to prove its efficacy in the assessment of the subject’s Heart Rate (HR) in comparison to standard algorithms (i.e. Pan & Tompkins). Results obtained in experimentally collected ECG signals for the identification of the main feature (R-peak) are comparable to those obtained with the traditional approach (sensitivity of 99.55% and 99.95%, respectively). Moreover, the use of this algorithm has been broaden to signals coming from different biomedical sensors (based on optical, acoustical and mechanical principles), all related to blood flow, for the computation of HR. In particular, it has been employed to PCG (Phonocardiography), PPG (Photoplethysmography) and VCG (Vibrocardiography), where standard algorithms could not be widely applied. HR results from a measurement campaign on 8 healthy subjects have shown, with respect to ECG, deviations (calculated as 2σ) of ±3.3 bpm, ±2.3 bpm and ±1.5 bpm for PCG, PPG and VCG, respectively. In conclusion, it is possible to state that the adopted algorithm is able to measure HR accurately from different biosignals. Future work will involve the extraction of additional morphological features in order to characterise the waveforms more deeply and to better describe the subject’s health status.

  14. Land use mapping from CBERS-2 images with open source tools by applying different classification algorithms

    Science.gov (United States)

    Sanhouse-García, Antonio J.; Rangel-Peraza, Jesús Gabriel; Bustos-Terrones, Yaneth; García-Ferrer, Alfonso; Mesas-Carrascosa, Francisco J.

    2016-02-01

    Land cover classification is often based on different characteristics between their classes, but with great homogeneity within each one of them. This cover is obtained through field work or by mean of processing satellite images. Field work involves high costs; therefore, digital image processing techniques have become an important alternative to perform this task. However, in some developing countries and particularly in Casacoima municipality in Venezuela, there is a lack of geographic information systems due to the lack of updated information and high costs in software license acquisition. This research proposes a low cost methodology to develop thematic mapping of local land use and types of coverage in areas with scarce resources. Thematic mapping was developed from CBERS-2 images and spatial information available on the network using open source tools. The supervised classification method per pixel and per region was applied using different classification algorithms and comparing them among themselves. Classification method per pixel was based on Maxver algorithms (maximum likelihood) and Euclidean distance (minimum distance), while per region classification was based on the Bhattacharya algorithm. Satisfactory results were obtained from per region classification, where overall reliability of 83.93% and kappa index of 0.81% were observed. Maxver algorithm showed a reliability value of 73.36% and kappa index 0.69%, while Euclidean distance obtained values of 67.17% and 0.61% for reliability and kappa index, respectively. It was demonstrated that the proposed methodology was very useful in cartographic processing and updating, which in turn serve as a support to develop management plans and land management. Hence, open source tools showed to be an economically viable alternative not only for forestry organizations, but for the general public, allowing them to develop projects in economically depressed and/or environmentally threatened areas.

  15. Applying different spatial distribution and modelling concepts in three nested mesoscale catchments of Germany

    Science.gov (United States)

    Bongartz, K.

    Distributed, physically based river basin models are receiving increasing importance in integrated water resources management (IWRM) in Germany and in Europe, especially after the release of the new European Water Framework Directive (WFD). Applications in mesoscale catchments require an appropriate approach to represent the spatial distribution of related catchment properties such as land use, soil physics and topography by utilizing techniques of remote sensing and GIS analyses. The challenge is to delineate scale independent homogeneous modelling entities which, on the one hand may represent the dynamics of the dominant hydrological processes and, on the other hand can be derived from spatially distributed physiographical catchment properties. This scaling problem is tackled in this regional modelling study by applying the concept of hydrological response units (HRUs). In a nested catchment approach three different modelling conceptualisations are used to describe the runoff processes: (i) the topographic stream-segment-based HRU delineation proposed by Leavesley et al. [Precipitation-Runoff-Modelling-System, User’s Manual, Water Resource Investigations Report 83-4238, US Geological Survey, 1983]; (ii) the process based physiographic HRU-concept introduced by Flügel [Hydrol. Process. 9 (1995) 423] and (iii) an advanced HRU-concept adapted from (ii), which included the topographic topology of HRU-areas and the river network developed by Staudenraush [Eco Regio 8 (2000) 121]. The influence of different boundary conditions associated with changing the landuse classes, the temporal data resolution and the landuse scenarios were investigated. The mesoscale catchment of the river Ilm ( A∼895 km 2) in Thuringia, Germany, and the Precipitation-Runoff-Modelling-System (PRMS) were selected for this study. Simulations show that the physiographic based concept is a reliable method for modelling basin dynamics in catchments up to 200 km 2 whereas in larger catchments

  16. Survey of Induced Voltage and Current Phenomena in GIS Substation

    Directory of Open Access Journals (Sweden)

    Seyed Mohammad Hassan Hosseini

    2014-03-01

    Full Text Available Induced capacitive voltage and current in high voltage GIS substation is one of the most significant phenomena that may have made some problems in this substation operation. At this study the various equipment of 420 KV Karoon4 substations such as powerhouses, input and output lines, bus-bar and bus-duct have simulated by applying EMTP-RV software. Then with the different condition of single-phase and three-phase faults on the lines in critical conditions, capacitive induction voltage and current by parallel capacitor with circuit breaker is surveyed. The results show the value of this induced current and voltage and that this critical conditions the breakers and dis-connector switches must be able to interrupt this value of current.

  17. Interpretation on Partial Discharge of Typical Insulation Model Under Oscillating Impulse Voltage

    Institute of Scientific and Technical Information of China (English)

    SUN Zhenquan; ZHAO Xuefeng; LI Jisheng; LI Yanming

    2012-01-01

    The aim of this paper was to give an overview on partial discharges under oscillating impulse voltage.Three models(void in solid,needle-plate in air and oil) were presented,which describe the stochastic discharge process and represent internal discharges in solids and corona in air or silicon oil.Moreover,an air cored Rogowski coil and a sampling resistor for partial discharge(PD) measurement were developed and introduced in this paper.PD inception and extinction voltages(PDIV,PDEV) under single oscillating impulse voltage and AC voltage were investigated with different test samples.Experimental results firstly revealed that the PD inception voltage(PDIV) decreased with increasing applied voltage;secondly the PD inception voltage for three different insulating materials,showed an escalating trend with increasing frequency of the applied voltage.It was proven that the characteristics of PD under oscillating impulse voltage were identical to the features under AC voltage,which could be measured with the phase resolved partial discharge analysis(PRPDA) technique.Based on the reorganization and analysis of PDs under oscillating impulse voltage,the information about insulation defects was extracted from the measured data and used for estimating the risk of insulation failure of the equipment.

  18. A compact, all solid-state LC high voltage generator.

    Science.gov (United States)

    Fan, Xuliang; Liu, Jinliang

    2013-06-01

    LC generator is widely applied in the field of high voltage generation technology. A compact and all solid-state LC high voltage generator based on saturable pulse transformer is proposed in this paper. First, working principle of the generator is presented. Theoretical analysis and circuit simulation are used to verify the design of the generator. Experimental studies of the proposed LC generator with two-stage main energy storage capacitors are carried out. And the results show that the proposed LC generator operates as expected. When the isolation inductance is 27 μH, the output voltage is 1.9 times larger than the charging voltage on single capacitor. The multiplication of voltages is achieved. On the condition that the primary energy storage capacitor is charged to 857 V, the output voltage of the generator can reach to 59.5 kV. The step-up ratio is nearly 69. When self breakdown gas gap switch is used as main switch, the rise time of the voltage pulse on load resistor is 8.7 ns. It means that the series-wound inductance in the discharging circuit is very small in this system. This generator can be employed in two different applications.

  19. Mitigation of cadmium and arsenic in rice grain by applying different silicon fertilizers in contaminated fields.

    Science.gov (United States)

    Wang, Hong-Yan; Wen, Shi-Lin; Chen, Peng; Zhang, Lu; Cen, Kuang; Sun, Guo-Xin

    2016-02-01

    A field experiment was established to support the hypothesis that application of different silicon (Si) fertilizers can simultaneously reduce cadmium (Cd) and arsenic (As) concentration in rice grain. The "semi-finished product of Si-potash fertilizer" treatment at the high application of 9000 kg/ha (NP+S-KSi9000) significantly reduced the As concentration in rice grain by up to 20.1%, compared with the control. Si fertilization reduces the Cd concentration in rice considerably more than the As concentration. All Si fertilizers apart from sodium metasilicate (Na2SiO3) exhibited a high ability to reduce Cd concentration in rice grain. The Si-calcium (CaSi) fertilizer is the most effective in the mitigation of Cd concentration in rice grain. The CaSi fertilizer applied at 9000 kg/ha (NPK+CaSi9000) and 900 kg/ha (NPK+CaSi900) reduced the Cd concentration in rice grain about 71.5 and 48.0%, respectively, while the Si-potash fertilizer at 900 kg/ha (NP+KSi900), the semi-finished product of Si-potash fertilizer at both 900 kg/ha (NP+S-KSi900) and 9000 kg/ha (NP+S-KSi9000), and the rice straw (NPK+RS) treatments reduced the Cd concentration in rice grain about 42, 26.5, 40.7, and 23.1%, respectively. The results of this investigation demonstrated the potential effects of Si fertilizers in reducing Cd and As concentrations in rice grain.

  20. Bioclimatic and vegetation mapping of a topographically complex oceanic island applying different interpolation techniques.

    Science.gov (United States)

    Garzón-Machado, Víctor; Otto, Rüdiger; del Arco Aguilar, Marcelino José

    2014-07-01

    Different spatial interpolation techniques have been applied to construct objective bioclimatic maps of La Palma, Canary Islands. Interpolation of climatic data on this topographically complex island with strong elevation and climatic gradients represents a challenge. Furthermore, meteorological stations are not evenly distributed over the island, with few stations at high elevations. We carried out spatial interpolations of the compensated thermicity index (Itc) and the annual ombrothermic Index (Io), in order to obtain appropriate bioclimatic maps by using automatic interpolation procedures, and to establish their relation to potential vegetation units for constructing a climatophilous potential natural vegetation map (CPNV). For this purpose, we used five interpolation techniques implemented in a GIS: inverse distance weighting (IDW), ordinary kriging (OK), ordinary cokriging (OCK), multiple linear regression (MLR) and MLR followed by ordinary kriging of the regression residuals. Two topographic variables (elevation and aspect), derived from a high-resolution digital elevation model (DEM), were included in OCK and MLR. The accuracy of the interpolation techniques was examined by the results of the error statistics of test data derived from comparison of the predicted and measured values. Best results for both bioclimatic indices were obtained with the MLR method with interpolation of the residuals showing the highest R2 of the regression between observed and predicted values and lowest values of root mean square errors. MLR with correction of interpolated residuals is an attractive interpolation method for bioclimatic mapping on this oceanic island since it permits one to fully account for easily available geographic information but also takes into account local variation of climatic data.

  1. Voltage and Pressure Scaling of Streamer Dynamics in a Helium Plasma Jet With N2 CO-Flow (Postprint)

    Science.gov (United States)

    2014-08-14

    increased applied voltage. These observed differences in the 2-D scaling properties of ionization wave sustained cathode directed streamer propagation in...streamer propagation in helium versus air16,17 are responsible for the observed differences in the propagation of ionization wave sustained streamer...increase quadratically with increased applied voltage. These observed differences in the 2-D scaling properties of ionization wave sustained cathode

  2. Voltage Management in Unbalanced Low Voltage Networks Using a Decoupled Phase-Tap-Changer Transformer

    OpenAIRE

    Coppo, Massimiliano; Turri, Roberto; Marinelli, Mattia; Han, Xue

    2014-01-01

    The paper studies a medium voltage-low voltage transformer with a decoupled on load tap changer capability on each phase. The overall objective is the evaluation of the potential benefits on a low voltage network of such possibility. A realistic Danish low voltage network is used for the analysis. The load profiles are characterized by using single phase measurement data on voltages, currents and active powers with a 10 minutes resolution. Different scenarios are considered: no tap action, th...

  3. 高压电力计量系统故障诊断与应用研究%The Fault Diagnosis and Applied Research of High Voltage Electric Power Metering System

    Institute of Scientific and Technical Information of China (English)

    王娟; 张瑾

    2013-01-01

    提出了一种新的应用于高压电力计量系统的电流互感器一次侧短路的故障检测方法.首先,通过理论分析得出网络阻抗与电流互感器一次侧短路之间的密切关系.其次,设计故障检测方法,对故障信号进行分析和研究.最后得出了一种在实际应用中可行的方案.%A new fault detection method of short circuit of the primary side of TA applied to high voltage electric power metering system is proposed.Firstly,through theory analysis the close relationship between network impedance and short circuit of the primary side of TA are obtained.Secondly,the method of fault detection to research and analyze the fault signal is designed.Lastly,a plan is obtained that is feasible in practical application.

  4. Opening of DNA chain due to force applied on different locations

    Science.gov (United States)

    Singh, Amar; Modi, Tushar; Singh, Navin

    2016-09-01

    We consider a homogeneous DNA molecule and investigate the effect of random force applied on the unzipping profile of the molecule. How the critical force varies as a function of the chain length or number of base pairs is the objective of this study. In general, the ratio of the critical forces that is applied on the middle of the chain to that which is applied on one of the ends is two. Our study shows that this ratio depends on the length of the chain. This means that the force which is applied to a point can be experienced by a section of the chain. Beyond a length, the base pairs have no information about the applied force. In the case when the chain length is shorter than this length, this ratio may vary. Only in the case when the chain length exceeds a critical length, this ratio is found to be two. Based on the de Gennes formulation, we developed a method to calculate these forces at zero temperature. The exact results at zero temperature match numerical calculations.

  5. Voltage stability analysis in the new deregulated environment

    Science.gov (United States)

    Zhu, Tong

    Nowadays, a significant portion of the power industry is under deregulation. Under this new circumstance, network security analysis is more critical and more difficult. One of the most important issues in network security analysis is voltage stability analysis. Due to the expected higher utilization of equipment induced by competition in a power market that covers bigger power systems, this issue is increasingly acute after deregulation. In this dissertation, some selected topics of voltage stability analysis are covered. In the first part, after a brief review of general concepts of continuation power flow (CPF), investigations on various matrix analysis techniques to improve the speed of CPF calculation for large systems are reported. Based on these improvements, a new CPF algorithm is proposed. This new method is then tested by an inter-area transaction in a large inter-connected power system. In the second part, the Arnoldi algorithm, the best method to find a few minimum singular values for a large sparse matrix, is introduced into the modal analysis for the first time. This new modal analysis is applied to the estimation of the point of voltage collapse and contingency evaluation in voltage security assessment. Simulations show that the new method is very efficient. In the third part, after transient voltage stability component models are investigated systematically, a novel system model for transient voltage stability analysis, which is a logical-algebraic-differential-difference equation (LADDE), is offered. As an example, TCSC (Thyristor controlled series capacitors) is addressed as a transient voltage stabilizing controller. After a TCSC transient voltage stability model is outlined, a new TCSC controller is proposed to enhance both fault related and load increasing related transient voltage stability. Its ability is proven by the simulation.

  6. Applying Holland's Typology to the Study of Differences in Student Views about Diversity

    Science.gov (United States)

    Umbach, Paul D.; Milem, Jeffrey F.

    2004-01-01

    Using data from a survey of more that 1900 first-year students at a large research institution, this paper applies Holland's theory of personality and environment to examine the ways in which students view diversity. Holland categories, individual characteristics such as race and gender, and interactions with people of color prior to college,…

  7. SVPWM Technique with Varying DC-Link Voltage for Common Mode Voltage Reduction in a Matrix Converter and Analytical Estimation of its Output Voltage Distortion

    Science.gov (United States)

    Padhee, Varsha

    Common Mode Voltage (CMV) in any power converter has been the major contributor to premature motor failures, bearing deterioration, shaft voltage build up and electromagnetic interference. Intelligent control methods like Space Vector Pulse Width Modulation (SVPWM) techniques provide immense potential and flexibility to reduce CMV, thereby targeting all the afore mentioned problems. Other solutions like passive filters, shielded cables and EMI filters add to the volume and cost metrics of the entire system. Smart SVPWM techniques therefore, come with a very important advantage of being an economical solution. This thesis discusses a modified space vector technique applied to an Indirect Matrix Converter (IMC) which results in the reduction of common mode voltages and other advanced features. The conventional indirect space vector pulse-width modulation (SVPWM) method of controlling matrix converters involves the usage of two adjacent active vectors and one zero vector for both rectifying and inverting stages of the converter. By suitable selection of space vectors, the rectifying stage of the matrix converter can generate different levels of virtual DC-link voltage. This capability can be exploited for operation of the converter in different ranges of modulation indices for varying machine speeds. This results in lower common mode voltage and improves the harmonic spectrum of the output voltage, without increasing the number of switching transitions as compared to conventional modulation. To summarize it can be said that the responsibility of formulating output voltages with a particular magnitude and frequency has been transferred solely to the rectifying stage of the IMC. Estimation of degree of distortion in the three phase output voltage is another facet discussed in this thesis. An understanding of the SVPWM technique and the switching sequence of the space vectors in detail gives the potential to estimate the RMS value of the switched output voltage of any

  8. Leaching of indaziflam applied at two rates under different rainfall situations in Florida Candler soil.

    Science.gov (United States)

    Jhala, Amit J; Ramirez, Analiza H M; Singh, Megh

    2012-03-01

    Indaziflam {N-[(1R, 2S)-2,3-dihydro-2,6-dimethyl-1H-inden-1-yl]-6-[(1RS)-1fluoroethyl]-1,3,5-triazine-2,4-diamine} is a new pre-emergence herbicide recently registered for a broad spectrum weed control in Florida citrus. Experiments were conducted to evaluate leaching of indaziflam applied at 73 and 145 g ai ha(-1) in Florida Candler soil under simulated rainfall of 5, 10, and 15 cm ha(-1). Indaziflam leached the least (12.6 ± 0.6 cm) when applied at 73 g ai ha(-1) under 5 cm ha(-1) rainfall. Indaziflam leached furthest (30.2 ± 0.9 cm) when applied at 145 g ai ha(-1) under 15 cm ha(-1) rainfall. The visual control ratings of a bio-indicator species ryegrass (Lolium multiflorum L.) was 97% at 15 cm ha(-1) rainfall when indaziflam applied at 145 g ai ha(-1) in the 26 to 30 cm horizon indicating the maximum movement and activity of indaziflam. A dose response experiment was conducted to determine the sensitivity of ryegrass to various doses of indaziflam that confirmed that application of indaziflam at 29.20 g ai ha(-1) was sufficient to prevent germination of ryegrass. There was no mortality of ryegrass plants beyond the 30 cm and the biomass of ryegrass was comparable with untreated control indicating that indaziflam did not leach beyond this distance even under 15 cm ha(-1) rainfall.

  9. Experimental validation of a high voltage pulse measurement method.

    Energy Technology Data Exchange (ETDEWEB)

    Cular, Stefan; Patel, Nishant Bhupendra; Branch, Darren W.

    2013-09-01

    This report describes X-cut lithium niobates (LiNbO3) utilization for voltage sensing by monitoring the acoustic wave propagation changes through LiNbO3 resulting from applied voltage. Direct current (DC), alternating current (AC) and pulsed voltage signals were applied to the crystal. Voltage induced shift in acoustic wave propagation time scaled quadratically for DC and AC voltages and linearly for pulsed voltages. The measured values ranged from 10 - 273 ps and 189 ps 2 ns for DC and non-DC voltages, respectively. Data suggests LiNbO3 has a frequency sensitive response to voltage. If voltage source error is eliminated through physical modeling from the uncertainty budget, the sensors U95 estimated combined uncertainty could decrease to ~0.025% for DC, AC, and pulsed voltage measurements.

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

    Science.gov (United States)

    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.

  11. GENDER DIFFERENCES IN APPLYING COMPLIMENTS AND COMPLIMENT RESPONSES IN CHINESE CONTEXT

    Institute of Scientific and Technical Information of China (English)

    OuanLihong

    2004-01-01

    The previous research done by the author shows that there exist significant differences between men and women in their realization patterns of compliments and compliment responses. These differences are reflected in the strategies used in complimenting and responding to compliments. Generally, women tend to use more polite strategies than men do. This article will explore these differences from both social and cultural perspectives.

  12. Calculation of the X-Ray Spectrum of a Mammography System with Various Voltages and Different Anode-Filter Combinations Using MCNP Code

    Directory of Open Access Journals (Sweden)

    Lida Gholamkar

    2016-09-01

    Full Text Available Introduction One of the best methods in the diagnosis and control of breast cancer is mammography. The importance of mammography is directly related to its value in the detection of breast cancer in the early stages, which leads to a more effective treatment. The purpose of this article was to calculate the X-ray spectrum in a mammography system with Monte Carlo codes, including MCNPX and MCNP5. Materials and Methods The device, simulated using the MCNP code, was Planmed Nuance digital mammography device (Planmed Oy, Finland, equipped with an amorphous selenium detector. Different anode/filter materials, such as molybdenum-rhodium (Mo-Rh, molybdenum-molybdenum (Mo-Mo, tungsten-tin (W-Sn, tungsten-silver (W-Ag, tungsten-palladium (W-Pd, tungsten-aluminum (W-Al, tungsten-molybdenum (W-Mo, molybdenum-aluminum (Mo-Al, tungsten-rhodium (W-Rh, rhodium-aluminum (Rh-Al, and rhodium-rhodium (Rh-Rh, were simulated in this study. The voltage range of the X-ray tube was between 24 and 34 kV with a 2 kV interval. Results The charts of changing photon flux versus energy were plotted for different types of anode-filter combinations. The comparison with the findings reported by others indicated acceptable consistency. Also, the X-ray spectra, obtained from MCNP5 and MCNPX codes for W-Ag and W-Rh combinations, were compared. We compared the present results with the reported data of MCNP4C and IPEM report No. 78 for Mo-Mo, Mo-Rh, and W-Al combinations. Conclusion The MCNPX calculation outcomes showed acceptable results in a low-energy X-ray beam range (10-35 keV. The obtained simulated spectra for different anode/filter combinations were in good conformity with the finding of previous research.

  13. A Synchrophasor Based Optimal Voltage Control Scheme with Successive Voltage Stability Margin Improvement

    Directory of Open Access Journals (Sweden)

    Heng-Yi Su

    2016-01-01

    Full Text Available This paper proposes an optimal control scheme based on a synchronized phasor (synchrophasor for power system secondary voltage control. The framework covers voltage stability monitoring and control. Specifically, a voltage stability margin estimation algorithm is developed and built in the newly designed adaptive secondary voltage control (ASVC method to achieve more reliable and efficient voltage regulation in power systems. This new approach is applied to improve voltage profile across the entire power grid by an optimized plan for VAR (reactive power sources allocation; therefore, voltage stability margin of a power system can be increased to reduce the risk of voltage collapse. An extensive simulation study on the IEEE 30-bus test system is carried out to demonstrate the feasibility and effectiveness of the proposed scheme.

  14. Gas sensing properties of branched carbon nanotube-based structures using a novel low voltage emission.

    Science.gov (United States)

    Darbari, S; Azimi, S; Abdi, Y; Mohajerzadeh, S

    2012-11-01

    Branched carbon nanostructures have been successfully grown on interdigital comb-like structures for a gas sensing application. Field emission scanning electron microscopy has been utilized to investigate the morphology and structure of the grown nanostructures at different stages of growth process. Tunneling current of the fabricated sensor has been measured when a monotonically increasing voltage is applied between the electrodes. The effect of exposure to three different gases on the measured current has been studied. A data processing on the measured current voltage characteristics results in the evolution of various peaks at distinct voltages which depends on the type of the gas.

  15. Comparison of Algorithms for Control of Loads for Voltage Regulation

    DEFF Research Database (Denmark)

    Douglass, Philip James; Han, Xue; You, Shi

    2014-01-01

    Autonomous flexible loads can be utilized to regulate voltag e on low voltage feeders. This paper compares two algorithms for controllin g loads: a simple voltage droop, where load power consumption is a varied in proportio n to RMS voltage; and a normalized relative voltage droop, which modifies...... the simpl e voltage droop by subtracting the mean voltage value at the bus and dividing by the standard deviation. These two controllers are applied to hot water heaters simul ated in a simple residential feeder. The simulation results show that both controllers r educe the frequency of undervoltage events...

  16. A torsional sensor for MEMS-based RMS voltage measurements

    Directory of Open Access Journals (Sweden)

    J. Dittmer

    2008-05-01

    Full Text Available RF voltage measurement based on electrostatic RMS voltage-to-force conversion is an alternative method in comparison to the conventional thermal power dissipation method. It is based on a mechanical force induced by an RF voltage applied to a micro-mechanical system. For a theoretically adequate resolution and high precision measurements, the necessary geometrical dimensions of the sensor require the application of micro machining. In this contribution, the dependence between electrical and geometrical properties of different sensor designs is investigated. Based on these results, problems related to practical micro-machining and solutions with respect to possible sensor realizations are discussed. The evolution of different sensor generations is shown.

  17. Transient Voltage Recorder

    Science.gov (United States)

    Medelius, Pedro J. (Inventor); Simpson, Howard J. (Inventor)

    2002-01-01

    A voltage transient recorder can detect lightning induced transient voltages. The recorder detects a lightning induced transient voltage and adjusts input amplifiers to accurately record transient voltage magnitudes. The recorder stores voltage data from numerous monitored channels, or devices. The data is time stamped and can be output in real time, or stored for later retrieval. The transient recorder, in one embodiment, includes an analog-to-digital converter and a voltage threshold detector. When an input voltage exceeds a pre-determined voltage threshold, the recorder stores the incoming voltage magnitude and time of arrival. The recorder also determines if its input amplifier circuits clip the incoming signal or if the incoming signal is too low. If the input data is clipped or too low, the recorder adjusts the gain of the amplifier circuits to accurately acquire subsequent components of the lightning induced transients.

  18. Investigation of sulphur isotope variation due to different processes applied during uranium ore concentrate production.

    Science.gov (United States)

    Krajkó, Judit; Varga, Zsolt; Wallenius, Maria; Mayer, Klaus; Konings, Rudy

    The applicability and limitations of sulphur isotope ratio as a nuclear forensic signature have been studied. The typically applied leaching methods in uranium mining processes were simulated for five uranium ore samples and the n((34)S)/n((32)S) ratios were measured. The sulphur isotope ratio variation during uranium ore concentrate (UOC) production was also followed using two real-life sample sets obtained from industrial UOC production facilities. Once the major source of sulphur is revealed, its appropriate application for origin assessment can be established. Our results confirm the previous assumption that process reagents have a significant effect on the n((34)S)/n((32)S) ratio, thus the sulphur isotope ratio is in most cases a process-related signature.

  19. Study and Experiment on Non-Contact Voltage Sensor Suitable for Three-Phase Transmission Line.

    Science.gov (United States)

    Zhou, Qiang; He, Wei; Xiao, Dongping; Li, Songnong; Zhou, Kongjun

    2015-12-30

    A voltage transformer, as voltage signal detection equipment, plays an important role in a power system. Presently, more and more electric power systems are adopting potential transformer and capacitance voltage transformers. Transformers are often large in volume and heavyweight, their insulation design is difficult, and an iron core or multi-grade capacitance voltage division structure is generally adopted. As a result, the detection accuracy of transformer is reduced, a huge phase difference exists between detection signal and voltage signal to be measured, and the detection signal cannot accurately and timely reflect the change of conductor voltage signal to be measured. By aiming at the current problems of electric transformation, based on electrostatic induction principle, this paper designed a non-contact voltage sensor and gained detection signal of the sensor through electrostatic coupling for the electric field generated by electric charges of the conductor to be measured. The insulation structure design of the sensor is simple and its volume is small; phase difference of sensor measurement is effectively reduced through optimization design of the electrode; and voltage division ratio and measurement accuracy are increased. The voltage sensor was tested on the experimental platform of simulating three-phase transmission line. According to the result, the designed non-contact voltage sensor can realize accurate and real-time measurement for the conductor voltage. It can be applied to online monitoring for the voltage of three-phase transmission line or three-phase distribution network line, which is in accordance with the development direction of the smart grid.

  20. Study and Experiment on Non-Contact Voltage Sensor Suitable for Three-Phase Transmission Line

    Directory of Open Access Journals (Sweden)

    Qiang Zhou

    2015-12-01

    Full Text Available A voltage transformer, as voltage signal detection equipment, plays an important role in a power system. Presently, more and more electric power systems are adopting potential transformer and capacitance voltage transformers. Transformers are often large in volume and heavyweight, their insulation design is difficult, and an iron core or multi-grade capacitance voltage division structure is generally adopted. As a result, the detection accuracy of transformer is reduced, a huge phase difference exists between detection signal and voltage signal to be measured, and the detection signal cannot accurately and timely reflect the change of conductor voltage signal to be measured. By aiming at the current problems of electric transformation, based on electrostatic induction principle, this paper designed a non-contact voltage sensor and gained detection signal of the sensor through electrostatic coupling for the electric field generated by electric charges of the conductor to be measured. The insulation structure design of the sensor is simple and its volume is small; phase difference of sensor measurement is effectively reduced through optimization design of the electrode; and voltage division ratio and measurement accuracy are increased. The voltage sensor was tested on the experimental platform of simulating three-phase transmission line. According to the result, the designed non-contact voltage sensor can realize accurate and real-time measurement for the conductor voltage. It can be applied to online monitoring for the voltage of three-phase transmission line or three-phase distribution network line, which is in accordance with the development direction of the smart grid.

  1. Inhibition of Voltage-Gated Calcium Channels After Subchronic and Repeated Exposure of PC12 Cells to Different Classes of Insecticides.

    Science.gov (United States)

    Meijer, Marieke; Brandsema, Joske A R; Nieuwenhuis, Desirée; Wijnolts, Fiona M J; Dingemans, Milou M L; Westerink, Remco H S

    2015-10-01

    We previously demonstrated that acute inhibition of voltage-gated calcium channels (VGCCs) is a common mode of action for (sub)micromolar concentrations of chemicals, including insecticides. However, because human exposure to chemicals is usually chronic and repeated, we investigated if selected insecticides from different chemical classes (organochlorines, organophosphates, pyrethroids, carbamates, and neonicotinoids) also disturb calcium homeostasis after subchronic (24 h) exposure and after a subsequent (repeated) acute exposure. Effects on calcium homeostasis were investigated with single-cell fluorescence (Fura-2) imaging of PC12 cells. Cells were depolarized with high-K(+) saline to study effects of subchronic or repeated exposure on VGCC-mediated Ca(2+) influx. The results demonstrate that except for carbaryl and imidacloprid, all selected insecticides inhibited depolarization (K(+))-evoked Ca(2+) influx after subchronic exposure (IC50's: approximately 1-10 µM) in PC12 cells. These inhibitory effects were not or only slowly reversible. Moreover, repeated exposure augmented the inhibition of the K(+)-evoked increase in intracellular calcium concentration induced by subchronic exposure to cypermethrin, chlorpyrifos, chlorpyrifos-oxon, and endosulfan (IC50's: approximately 0.1-4 µM). In rat primary cortical cultures, acute and repeated chlorpyrifos exposure also augmented inhibition of VGCCs compared with subchronic exposure. In conclusion, compared with subchronic exposure, repeated exposure increases the potency of insecticides to inhibit VGCCs. However, the potency of insecticides to inhibit VGCCs upon repeated exposure was comparable with the inhibition previously observed following acute exposure, with the exception of chlorpyrifos. The data suggest that an acute exposure paradigm is sufficient for screening chemicals for effects on VGCCs and that PC12 cells are a sensitive model for detection of effects on VGCCs. © The Author 2015. Published by Oxford

  2. Voltage source inverters for high power, variable-voltage DC power sources

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Z. [Department of Engineering and Technology, De Montfort University, Queens Building, The Gateway, Leicester, LE1 9BH, (United Kingdom); Spooner, E. [School of Engineering, University of Durham, Science Laboratories, South Rd, Durham, DRI 3LE, (United Kingdom)

    2001-09-01

    The paper discusses the applications of voltage source inverter (VSI) based power electronic systems for interfacing variable-voltage DC sources to the grid. A variable-speed wind power conversion system is used for illustration, where the VSI-based interface needs to convert a variable DC voltage to a nearly constant AC voltage with high-quality power. The power control principles of VSI are described. Various system configurations and switching strategies are examined by analysis, simulation and experimental methods. It is shown that better utilisation of semiconductors and more flexible control may be achieved by using a separately controlled DC link, rather than a directly connected VSI that has to operate at a lower modulation ratio at higher power. In some cases, multipulse inverter structures may be preferred, despite higher component count, because of reduced switching losses, fault tolerance and the absence of filters. The solutions developed in the study could be applied at a different scale to other renewable energy sources, such as wave or solar photovoltaic devices. (Author)

  3. [Absorption and utilization of different applied nitrogen forms by winter jujube].

    Science.gov (United States)

    Peng, Yong; Peng, Fu-tian; Zhou, Peng; Zhang, Xiao-yan

    2007-06-01

    With pot experiment, this paper studied the absorption and utilization of applied urea N, Gly N and Glu N by two years old winter jujube. The results showed that all of the three N forms could be absorbed by the winter jujube, but the absorption rate of Gly N and Glu N was less than that of urea N. Taking the absorption rate of urea N as 100%, the relative absorption rate of Gly N and Glu N by jujube leaves was 28.88% and 11.73%, respectively, and the absorbed N was mainly allocated to the leaves and neonatal branches. Jujube roots could absorb 50.48% of Gly N and 42.72% of Glu N. The transaminase activity and soluble protein content in jujube leaves were increased after the application of these three N forms, but the leaf nitrate reductase activity was enhanced significantly by urea N, decreased by Gly N, and less affected by Glu N. Compared with urea N, amino acid N could significantly increase the number of colored fruits and their colored area, as well as the content of fruit soluble solid matter.

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

    Directory of Open Access Journals (Sweden)

    Zhibin Hao

    Full Text Available 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.

  5. Cotton NDVI response to applied N at different soil EC levels

    Science.gov (United States)

    Many fields in the southeastern Coastal Plain are highly variable in soil physical properties and are irregular in shape. These two conditions may make it difficult to determine the ‘best’ area in the field to place nitrogen (N) -rich strips for normalized difference vegetative index (NDVI) -based s...

  6. The impact of applying different metrics in target definitions : lessons for policy design

    NARCIS (Netherlands)

    Harmsen, Robert

    2016-01-01

    The objective of this paper is to analyse the impact of the use of different metrics in the EU renewable energy target definition. The analysis, using a case study of the Dutch renewable energy support for illustration, reveals that a target based on primary energy would have led to a ranking in whi

  7. Observation on the adverse reactions of different concentrations of povidone-iodine applied before cataract surgery

    Directory of Open Access Journals (Sweden)

    Shan-Jun Wu

    2013-12-01

    Full Text Available AIM: To evaluate the efficiency and safety of 50g/L povidone-iodine solution in preventing postoperative endophthalmitis through comparing the incidence of postoperative endophthalmitis and adverse reactions after conjunctival sac washing with povidone-iodine of different concentrations.METHODS: Totally 500 cataract patients were divided into 50g/L povidone-iodine group and 25g/L povidone-iodine group. All the operated eyes were observed during and after surgery.The patients' subjective discomfort was inquired and their signs of eyes were recorded. RESULTS: The eye irritation of 50g/L povidone-iodine group was more significant than 25g/L povidone-iodine group. No significant difference in the corneal epithelial loss and endophthalmitis was observed between two groups.CONCLUSION:Conjunctival sac washing with 50g/L povidone-iodine is an effective and safe measure to prevent endophthalmitis after cataract surgery.

  8. A survey of applied approaches for software encryption of data in different operating systems

    OpenAIRE

    Damjanović, Boris; Simić, Dejan

    2013-01-01

    Along with the increased amount of digital information that are stored in computer systems increases the importance of protecting this information. Today's operating systems offer a number of different mechanisms to encrypt data that often provide unequal levels of protection. In this paper we provide an overview of basic block based and file based cryptographic solutions that are used in operating systems along with the presentation of efforts to unify cryptographic APIs in Linux and Windows...

  9. Cultural Differences Applied in International Marketing : Cases Of McDonalds and Red Bull

    OpenAIRE

    Abdulkerimova, Assiyat

    2017-01-01

    The main purpose of this thesis is to demonstrate how culture and cultural differences influence on the international marketing. Also, it demonstrates how international companies deal with cross-cultural issues and problems. First, the importance of culture and two models of cultural dimensions like Hofstede and Trompenaars will be analyzed and discussed. Second, the marketing activities of two international corporations- McDonald's and Red Bull will be discussed and analyzed. The research wi...

  10. Applying health economics for policy decision making: do devices differ from drugs?

    Science.gov (United States)

    Sorenson, Corinna; Tarricone, Rosanna; Siebert, Markus; Drummond, Michael

    2011-05-01

    Medical devices pose unique challenges for economic evaluation and associated decision-making processes that differ from pharmaceuticals. We highlight and discuss these challenges in the context of cardiac device therapy, based on a systematic review of relevant economic evaluations. Key challenges include practical difficulties in conducting randomized clinical trials, allowing for a 'learning curve' and user characteristics, accounting for the wider organizational impacts of introducing new devices, and allowing for variations in product characteristics and prices over time.

  11. CONTROL OF DICHELOPS MELACANTHUS WITH INSECTICIDES ASSOCIATED WITH SULPHUR APPLIED IN DIFFERENT TIMES IN CORN

    Directory of Open Access Journals (Sweden)

    J. C. Guerreiro

    2017-02-01

    Full Text Available The stink bug Dichelops melacanthus has become an important pest for corn crop and it has been causing several losses even in the initial phase of the crop. The objective of the experiment was the evaluation of effectiveness of the insecticides on the control of D. melacanthus in corn by adding of sulfur or not, in different control times. In order to evaluate the effect of the insecticide by adding or not sulfur on the control of D. melacanthus, 17 treatments with 4 different insecticides (with and without sulfur, in two different control times plus control were used to get the results. The experimental design used was the randomized blocks, with four repetitions. The evaluation of effectiveness on stink bugs control was gotten by visual evaluation of the symptoms at 6, 13 and 20 days after emergence (DAE. Analysis of variance by F test (Anova was done and the averages compared through Scott-knott test (p≤0,05. The pulverization of insecticides was more effective when it was done 4 (DAE, reducing the symptoms and injuries occasioned by the stink bug D. melacanthus and the mortality of damaged plants. The insecticide bifentrina+carbosulfano showed the higher effectiveness on stink bug control. To conclude, the use of sulfur associated to insecticides did not present a significant effect.

  12. What Is Taught in an Undergraduate Lecture? Differences Between a Matched Pair of Pure and Applied Disciplines.

    Science.gov (United States)

    Hativa, Nira

    1995-01-01

    Two lessons from comparable undergraduate courses in physics and engineering are analyzed to identify content, issues emphasized, and concepts used. Differences reflecting the pure nature of one field (physics) in contrast to the applied nature of the other are identified. Implications for classroom instruction and for research on college teaching…

  13. Inhibition of voltage-gated calcium channels after subchronic and repeated exposure of PC12 cells to different classes of insecticides

    NARCIS (Netherlands)

    Meijer, Marieke; Brandsema, Joske A R; Nieuwenhuis, Desirée; Wijnolts, Fiona M J; Dingemans, Milou M L; Westerink, Remco H S

    2015-01-01

    We previously demonstrated that acute inhibition of voltage-gated calcium channels (VGCCs) is a common mode of action for (sub)micromolar concentrations of chemicals, including insecticides. However, since human exposure to chemicals is usually chronic and repeated, we investigated if selected insec

  14. Inhibition of voltage-gated calcium channels after subchronic and repeated exposure of PC12 cells to different classes of insecticides

    NARCIS (Netherlands)

    Meijer, Marieke; Brandsema, Joske A R; Nieuwenhuis, Desirée; Wijnolts, Fiona M J; Dingemans, Milou M L|info:eu-repo/dai/nl/304834564; Westerink, Remco H S|info:eu-repo/dai/nl/239425952

    2015-01-01

    We previously demonstrated that acute inhibition of voltage-gated calcium channels (VGCCs) is a common mode of action for (sub)micromolar concentrations of chemicals, including insecticides. However, since human exposure to chemicals is usually chronic and repeated, we investigated if selected insec

  15. Boundary and Interface Conditions for High Order Finite Difference Methods Applied to the Euler and Navier-Strokes Equations

    Science.gov (United States)

    Nordstrom, Jan; Carpenter, Mark H.

    1998-01-01

    Boundary and interface conditions for high order finite difference methods applied to the constant coefficient Euler and Navier-Stokes equations are derived. The boundary conditions lead to strict and strong stability. The interface conditions are stable and conservative even if the finite difference operators and mesh sizes vary from domain to domain. Numerical experiments show that the new conditions also lead to good results for the corresponding nonlinear problems.

  16. Fracture toughness of bleached enamel: Effect of applying three different nanobiomaterials by nanoindentation test

    Directory of Open Access Journals (Sweden)

    Maryam Khoroushi

    2016-01-01

    Full Text Available Background: Despite the absence of dispute about the efficacy of bleaching agents, a prime concern is about their compromising effect on the enamel structure. This in vitro study investigated whether the addition of three different biomaterials, including nano-bioactive glass (n-BG/nano-hydroxy apetite (n-HA/nano-amorphous calcium phosphate (n-ACP, to bleaching agents can affect the fracture toughness (FT and vickers hardness number (VHN of bovine enamel. Materials and Methods: The crowns of the newly extracted permanent bovine incisors teeth were separated from the root and sectioned along their central line; one half serving as the control specimen and the other half as the test specimen. After mounting and polishing procedure, all the control specimens (C were subjected to nano-indentation test to obtain the baseline values of FT. Then, the control specimens were exposed to a 38% hydrogen peroxide for four times, each time for 10 min. The test specimens were divided into three groups and treated as follows, with the same protocol used for the control specimens: Group 1; ACP + hydrogen peroxide (HP mixed gel; Group 2 BG + HP mixed gel; and Group 3 HA + HP mixed gel. FT measurements with nano-indentation were carried out subsequent to bleaching experiments. Data were analyzed using SPSS and Kruskal–Wallis test (α = 0.05. Results: A significant difference in young's modulus (YM, VHN, and FT at baseline and subsequent to bleaching in control group was observed. However, no significant differences were found in YM, VHN, and FT between the test groups, compared to the respective baseline values. Conclusion: Under the limitations of the current study, it can be concluded that the n-HA, n-ACP, and n-BG could be potential biomaterials used to reduce the adverse effects of tooth bleaching.

  17. Evaluation of landmine detection performance applying two different algorithms to GPR field data

    Science.gov (United States)

    Mendez-Rial, Roi; Uschkerat, U.; Rial, F. I.; Gonzalez-Huici, Maria A.

    2013-06-01

    This paper evaluates and compares the performance of two algorithms that have previously demonstrated their potential in underground target detection. Field data was obtained on specially prepared test fields, where various mine simulants, reference objects, and mine-like clutter where placed at precise locations in different soil types. The efficiency of both algorithms in terms of detection accuracies (ROC curves) and computational burden is compared, as well as the impact of preprocessing strategies. Based on the results, we discuss the convenience of both methods to be integrated in a real - time signal processing system considering their benefits and drawbacks.

  18. Optimized explicit Runge-Kutta schemes for the spectral difference method applied to wave propagation problems

    CERN Document Server

    Parsani, M; Deconinck, W

    2012-01-01

    Explicit Runge-Kutta schemes with large stable step sizes are developed for integration of high order spectral difference spatial discretization on quadrilateral grids. The new schemes permit an effective time step that is substantially larger than the maximum admissible time step of standard explicit Runge-Kutta schemes available in literature. Furthermore, they have a small principal error norm and admit a low-storage implementation. The advantages of the new schemes are demonstrated through application to the Euler equations and the linearized Euler equations.

  19. Optimized Explicit Runge--Kutta Schemes for the Spectral Difference Method Applied to Wave Propagation Problems

    KAUST Repository

    Parsani, Matteo

    2013-04-10

    Explicit Runge--Kutta schemes with large stable step sizes are developed for integration of high-order spectral difference spatial discretizations on quadrilateral grids. The new schemes permit an effective time step that is substantially larger than the maximum admissible time step of standard explicit Runge--Kutta schemes available in the literature. Furthermore, they have a small principal error norm and admit a low-storage implementation. The advantages of the new schemes are demonstrated through application to the Euler equations and the linearized Euler equations.

  20. Effect of Early Intervention Applied to Patients with Chronic Obstructive Pulmonary Disease at Different Stages

    Directory of Open Access Journals (Sweden)

    W Lei

    2014-04-01

    Full Text Available Objective: Early intervention in chronic obstructive pulmonary disease (COPD includes health education, smoking cessation, pulmonary rehabilitation and enhancing immunity (administration of influenza vaccine and polysaccharide nucleic acid fraction of bacillus Calmette-Guerin [BCG-PSN]. The effect of early intervention was investigated systematically in patients with COPD at different stages. Methods: We enrolled 422 patients with COPD at different stages without symptoms and then randomly assigned them to intervention and control groups. The intervention group was provided with early intervention and usual care while the control group was only provided with usual care. One year of follow-up was performed to observe forced expiratory volume in one second (FEV1, FEV1/forced vital capacity (FVC, and the ratio of patients with acute exacerbation (number of patients with acute exacerbation/total of patients. Results: The values of decline in FEV1 and FEV1/FVC were significantly lower in the intervention groups of stage I and II than control groups (all p 0.05. The ratios of patients with acute exacerbation were lower in the intervention groups of all the stages than the control groups (p < 0.05. Conclusion: Early intervention could slow the decline of FEV1 and FEV1/FVC in patients with COPD in stages I and II, but not in stages III and IV. Early intervention could also prevent patients with COPD from getting acute exacerbation and improve their quality of life in all the stages of the disease.

  1. Applying a reservoir functional-zone paradigm to littoral bluegills: differences in length and catch frequency?

    Science.gov (United States)

    Ruhl, Nathan; DeAngelis, Holly; Crosby, Abigale M; Roosenburg, Willem M

    2014-01-01

    Reservoirs exhibit gradients in conditions and resources along the transition from lotic to lentic habitat that may be important to bluegill ecology. The lotic-lentic gradient can be partitioned into three functional zones: the riverine, transitional, and lacustrine zones. We measured catch frequency and length of bluegills (Lepomis macrochirus) captured along the periphery of these areas (i.e., in the littoral zone of each functional zone) for four small reservoirs in Southeastern Ohio during the summer months of three years. Catch frequency differed between zones for two reservoirs, but these differences were not observed in other years. There was no relationship between reservoir zone and either standard length or catch frequency when the data for all reservoirs were pooled, but we did observe a bimodal length distribution in all reservoirs. A combination of ecological factors including inter and intraspecific competition, predation intensity, management practices, limnology, and assemblage complexity may be mitigating bluegill distribution and abundance in reservoirs. Therefore, a functional zone (categorical) approach to understanding bluegill ecology in reservoirs may not be appropriate.

  2. Applying a reservoir functional-zone paradigm to littoral bluegills: differences in length and catch frequency?

    Directory of Open Access Journals (Sweden)

    Nathan Ruhl

    2014-08-01

    Full Text Available Reservoirs exhibit gradients in conditions and resources along the transition from lotic to lentic habitat that may be important to bluegill ecology. The lotic–lentic gradient can be partitioned into three functional zones: the riverine, transitional, and lacustrine zones. We measured catch frequency and length of bluegills (Lepomis macrochirus captured along the periphery of these areas (i.e., in the littoral zone of each functional zone for four small reservoirs in Southeastern Ohio during the summer months of three years. Catch frequency differed between zones for two reservoirs, but these differences were not observed in other years. There was no relationship between reservoir zone and either standard length or catch frequency when the data for all reservoirs were pooled, but we did observe a bimodal length distribution in all reservoirs. A combination of ecological factors including inter and intraspecific competition, predation intensity, management practices, limnology, and assemblage complexity may be mitigating bluegill distribution and abundance in reservoirs. Therefore, a functional zone (categorical approach to understanding bluegill ecology in reservoirs may not be appropriate.

  3. Automatic voltage imbalance detector

    Science.gov (United States)

    Bobbett, Ronald E.; McCormick, J. Byron; Kerwin, William J.

    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.

  4. Assessment of soil organic matter persistence under different land uses applying a physical fractionation procedure

    Science.gov (United States)

    Giannetta, Beatrice; Plaza, César; López-de-Sá, Esther G.; Vischetti, Costantino; Zaccone, Claudio

    2017-04-01

    The understanding of the mechanisms involved in the build-up of soil organic matter (SOM) pools with long residence time is tightly linked to the comprehension of C dynamics. Organo-mineral associations are known to be strongly correlated with the accumulation of selective preserved C forms. Adsorption to minerals, as well as occlusion within aggregates, may affect SOM protection in different ways depending on its molecular structure and pedo-climatic conditions. In this research, we investigated changes in quantity and quality of SOM pools characterized by different protection mechanisms in coniferous and broadleaved forest soils, grassland soils, technosols and an agricultural soil with different organic amendments, in order to evaluate the influence of both land use and organic matter nature on physical and/or chemical stabilization of SOM. In particular, free (FR), intra-macroaggregate (MA), intra-microaggregate (MI), and mineral-associated (Min) fractions were separated in order to define physical and chemical mechanisms responsible for the SOM protection against degradation. All these SOM fractions were analyzed for organic C and total N concentration, and their stability assessed by thermogravimetric analysis (TD-TGA). Preliminary data show that, for all land uses, most of the organic C (40-60%) is found in the Min pool, followed by FR (20-40%)>MI MA. With the only exception of the FR, no significant correlations were found between the C/N ratio and a thermal stability index (H550-400/400-250) of each fraction; at the same time, a highly significant and positive correlation was found between these two parameters in all fractions isolated from agricultural soils. In particular, the thermal stability index measured in all Min fractions may be related to the more marked presence of labile compounds in this pool relative to recalcitrant compounds. Conversely, FR OM could not always represent a fresh and readily decomposable fraction.Furthermore, OM associated

  5. Performance of different fire retardant products applied on Norway spruce tested in a Cone calorimeter

    Directory of Open Access Journals (Sweden)

    Kögl Josef

    2013-11-01

    Full Text Available On the European market there are several fire retardant products available, which reach class B in the European classification system. The producers promise their fire retardants are effective in reducing different reaction to fire parameters of wood such as the time to ignition, the mass loss rate, the heat release rate, the total heat release, the charring rate and the flame spread. This paper discusses the performance of fire retardant products as pressure impregnated wood, non-intumescence surface coatings and intumescence coatings on Norway spruce (Picea abies. The investigations are performed by using a cone calo- rimeter test according to ISO 5660. The thermal exposures of the investigations are 50 kW/m2 and the standard IS0 834 test curve. As result information about the heat release rate, the mass loss rate and the total heat release for duration of 900 seconds will be presented in this paper.

  6. The different effects of applying fresh, composted or charred manure on soil N2O emissions

    DEFF Research Database (Denmark)

    Zhu, Kun; Christel, Wibke; Bruun, Sander;

    2014-01-01

    New manure management strategies and technologies are currently being developed in order to reduce manure volume and odorous emissions, utilise energy potential and produce improved manure-derived fertilisers. This has accentuated the need to determine their effects on greenhouse gas emissions...... to higher N2O and CO2 emissions than heterogeneous distribution. However, the effect of different distribution modes was not significant in treatments with charred manure, since N turnover in the immature compost was much more active than that in the charred manure. By combining charred manure...... with composted manure, N2O emissions were significantly reduced by 41% at pF 2.0, but the mitigation effect of charred manure was not observed at lower soil water potentials. © 2014 Elsevier Ltd....

  7. Study of different filtering techniques applied to spectra from airborne gamma spectrometry.

    Science.gov (United States)

    Wilhelm, Emilien; Gutierrez, Sébastien; Arbor, Nicolas; Ménard, Stéphanie; Nourreddine, Abdel-Mjid

    2016-11-01

    One of the features of the spectra obtained by airborne gamma spectrometry is the low counting statistics due to a short acquisition time (1 s) and a large source-detector distance (40 m) which leads to large statistical fluctuations. These fluctuations bring large uncertainty in radionuclide identification and determination of their respective activities from the window method recommended by the IAEA, especially for low-level radioactivity. Different types of filter could be used on spectra in order to remove these statistical fluctuations. The present work compares the results obtained with filters in terms of errors over the whole gamma energy range of the filtered spectra with the window method. These results are used to determine which filtering technique is the most suitable in combination with some method for total stripping of the spectrum.

  8. A Comparison between Different Error Modeling of MEMS Applied to GPS/INS Integrated Systems

    Directory of Open Access Journals (Sweden)

    Fabio Dovis

    2013-07-01

    Full Text Available Advances in the development of micro-electromechanical systems (MEMS have made possible the fabrication of cheap and small dimension accelerometers and gyroscopes, which are being used in many applications where the global positioning system (GPS and the inertial navigation system (INS integration is carried out, i.e., identifying track defects, terrestrial and pedestrian navigation, unmanned aerial vehicles (UAVs, stabilization of many platforms, etc. Although these MEMS sensors are low-cost, they present different errors, which degrade the accuracy of the navigation systems in a short period of time. Therefore, a suitable modeling of these errors is necessary in order to minimize them and, consequently, improve the system performance. In this work, the most used techniques currently to analyze the stochastic errors that affect these sensors are shown and compared: we examine in detail the autocorrelation, the Allan variance (AV and the power spectral density (PSD techniques. Subsequently, an analysis and modeling of the inertial sensors, which combines autoregressive (AR filters and wavelet de-noising, is also achieved. Since a low-cost INS (MEMS grade presents error sources with short-term (high-frequency and long-term (low-frequency components, we introduce a method that compensates for these error terms by doing a complete analysis of Allan variance, wavelet de-nosing and the selection of the level of decomposition for a suitable combination between these techniques. Eventually, in order to assess the stochastic models obtained with these techniques, the Extended Kalman Filter (EKF of a loosely-coupled GPS/INS integration strategy is augmented with different states. Results show a comparison between the proposed method and the traditional sensor error models under GPS signal blockages using real data collected in urban roadways.

  9. Different spectrophotometric methods applied for the analysis of binary mixture of flucloxacillin and amoxicillin: A comparative study

    Science.gov (United States)

    Attia, Khalid A. M.; Nassar, Mohammed W. I.; El-Zeiny, Mohamed B.; Serag, Ahmed

    2016-05-01

    Three different spectrophotometric methods were applied for the quantitative analysis of flucloxacillin and amoxicillin in their binary mixture, namely, ratio subtraction, absorbance subtraction and amplitude modulation. A comparative study was done listing the advantages and the disadvantages of each method. All the methods were validated according to the ICH guidelines and the obtained accuracy, precision and repeatability were found to be within the acceptable limits. The selectivity of the proposed methods was tested using laboratory prepared mixtures and assessed by applying the standard addition technique. So, they can be used for the routine analysis of flucloxacillin and amoxicillin in their binary mixtures.

  10. Morphological and chemical changes of dentin after applying different sterilization methods

    Directory of Open Access Journals (Sweden)

    Cláudio Antonio Talge Carvalho

    Full Text Available Aim The present study evaluated the morphological and chemical changes of dentin produced by different sterilization methods, using scanning electron microscopy (SEM and energy-dispersive X-ray spectrometry (EDS analysis. Material and method Five human teeth were sectioned into 4 samples, each divided into 3 specimens. The specimens were separated into sterilization groups, as follows: wet heat under pressure; cobalt 60 gamma radiation; and control (without sterilization. After sterilization, the 60 specimens were analyzed by SEM under 3 magnifications: 1500X, 5000X, and 10000X. The images were analyzed by 3 calibrated examiners, who assigned scores according to the changes observed in the dentinal tubules: 0 = no morphological change; 1, 2 and 3 = slight, medium and complete obliteration of the dentinal tubules. The chemical composition of dentin was assessed by EDS, with 15 kV incidence and 1 μm penetration. Result The data obtained were submitted to the statistical tests of Kruskall-Wallis and ANOVA. It was observed that both sterilization methods – with autoclave and with cobalt 60 gamma radiation – produced no significant changes to the morphology of the dentinal tubules or to the chemical composition of dentin. Conclusion Both methods may thus be used to sterilize teeth for research conducted in vitro.

  11. Amplitude differences least squares method applied to temporal cardiac beat alignment

    Energy Technology Data Exchange (ETDEWEB)

    Correa, R O [Gabinete de TecnologIa Medica, Facultad de Ingenieria, Universidad Nacional de San Juan (Argentina); Laciar, E [Gabinete de TecnologIa Medica, Facultad de Ingenieria, Universidad Nacional de San Juan (Argentina); Valentinuzzi, M E [Gabinete de TecnologIa Medica, Facultad de Ingenieria, Universidad Nacional de San Juan (Argentina)

    2007-11-15

    High resolution averaged ECG is an important diagnostic technique in post-infarcted and/or chagasic patients with high risk of ventricular tachycardia (VT). It calls for precise determination of the synchronism point (fiducial point) in each beat to be averaged. Cross-correlation (CC) between each detected beat and a reference beat is, by and large, the standard alignment procedure. However, the fiducial point determination is not precise in records contaminated with high levels of noise. Herein, we propose an alignment procedure based on the least squares calculation of the amplitude differences (LSAD) between the ECG samples and a reference or template beat. Both techniques, CC and LSAD, were tested in high resolution ECG's corrupted with white noise and 50 Hz line interference of varying amplitudes (RMS range: 0-100{mu}V). Results point out that LSDA produced a lower alignment error in all contaminated records while in those blurred by power line interference better results were found only within the 0-40 {mu}V range. It is concluded that the proposed method represents a valid alignment alternative.

  12. Perceiving Time Differences When You Should Not: Applying the El Greco Fallacy to Hypnotic Time Distortions

    Science.gov (United States)

    Martin, Jean-Rémy; Sackur, Jérôme; Anlló, Hernan; Naish, Peter; Dienes, Zoltan

    2016-01-01

    The way we experience and estimate time – subjective time – does not systematically correspond to objective time (the physical duration of an event). Many factors can influence subjective time and lead to mental dilation or compression of objective time. The emotional valence of stimuli or the levels of attention or expectancy are known to modulate subjective time even though objective time is constant. Hypnosis too is known to alter people’s perception of time. However, it is not known whether hypnotic time distortions are intrinsic perceptual effects, based for example on the changing rate of an internal clock, or rather the result of a response to demand characteristics. Here we distinguished the theories using the logic of the El Greco fallacy. When participants initially had to compare the duration of two successive events —with the same duration — while in “trance,” they responded that the second event was on average longer than the first event. As both events were estimated in “trance,” if hypnosis had impacted on an internal clock, they should have been affected to the same extent. Conversely, when only the first event was in “trance,” there was no difference in perceived duration. The findings conform to an El Greco fallacy effect and challenge theories of hypnotic time distortion arguing that “trance” itself changes subjective time. PMID:27625623

  13. Perceiving Time Differences When You Should Not: Applying the El Greco Fallacy to Hypnotic Time Distortions.

    Science.gov (United States)

    Martin, Jean-Rémy; Sackur, Jérôme; Anlló, Hernan; Naish, Peter; Dienes, Zoltan

    2016-01-01

    The way we experience and estimate time - subjective time - does not systematically correspond to objective time (the physical duration of an event). Many factors can influence subjective time and lead to mental dilation or compression of objective time. The emotional valence of stimuli or the levels of attention or expectancy are known to modulate subjective time even though objective time is constant. Hypnosis too is known to alter people's perception of time. However, it is not known whether hypnotic time distortions are intrinsic perceptual effects, based for example on the changing rate of an internal clock, or rather the result of a response to demand characteristics. Here we distinguished the theories using the logic of the El Greco fallacy. When participants initially had to compare the duration of two successive events -with the same duration - while in "trance," they responded that the second event was on average longer than the first event. As both events were estimated in "trance," if hypnosis had impacted on an internal clock, they should have been affected to the same extent. Conversely, when only the first event was in "trance," there was no difference in perceived duration. The findings conform to an El Greco fallacy effect and challenge theories of hypnotic time distortion arguing that "trance" itself changes subjective time.

  14. Perceiving time differences when you should not: Applying the El Greco fallacy to hypnotic time distortions

    Directory of Open Access Journals (Sweden)

    Jean-Rémy Martin

    2016-08-01

    Full Text Available The way we experience and estimate time – subjective time – does not systematically correspond to objective time (the physical duration of an event. Many factors can influence subjective time and lead to mental dilation or compression of objective time. The emotional valence of stimuli or the level of attention or expectancy are known to modulate subjective time although objective time is constant. Hypnosis too is known to alter people’s perception of time. However, it is not known whether hypnotic time distortions are intrinsic perceptual effects, based for example on the changing rate of an internal clock, or rather the result of a response to demand characteristics. Here we distinguished the theories using the logic of the El Greco fallacy. When participants initially had to compare the duration of two successive events —with the same duration — while in trance, they responded that the second event was on average longer than the first event. As both events were estimated in trance, if hypnosis impacted an internal clock, they should have been affected to the same extent. Conversely, when only the first event was in trance, there was no difference in perceived duration. The findings conform to an El Greco fallacy effect and challenge theories of hypnotic time distortion arguing that trance itself changes subjective time.

  15. Electronic medical archives: a different approach to applying re-signing mechanisms to digital signatures.

    Science.gov (United States)

    Chen, Tzer-Long; Lin, Frank Y S

    2011-08-01

    Electronic medical records can be defined as a digital format of the traditionally paper-based anamneses, which contains the history of a patient such as his somewhat illness, current health problems, and his chronic treatments. An electronic anamnesis is meant to make the patient's health information more conveniently accessible and transferable between different medical institutions and also easier to be kept quite a long time. Because of such transferability and accessibility of electronic anamneses, we can use less resource than before on storing the patients' medical information. This also means that medical care providers could save more funds on record-keeping and access a patient's medical background directly since shown on the computer screen more quickly and easily. Overall, the service quality has seemingly improved greatly. However, the usage of electronic anamneses involves in some concerned issues such as its related law declaration, and the security of the patient's confidential information. Because of these concerns, a secure medical networking scheme is taking into consideration. Nowadays, the administrators at the medical institutions are facing more challenges on monitoring computers and network systems, because of dramatic advances in this field. For instance, a trusted third party is authorized to access some medical records for a certain period of time. In regard to the security purpose, all the electronic medical records are embedded with both of the public-key infrastructure (PKI) cryptography and the digital signature technique so as to ensure the records well-protected. Since the signatures will be invalid due to the revocation or time expiration, the security of records under this premise would turn into vulnerable. Hence, we propose a re-signing scheme, whose purpose is to make a going-expired digital signature been resigned in time, in keeping with the premise of not conflicting with the laws, morals, and privacy while maintaining the

  16. Identifying allosteric fluctuation transitions between different protein conformational states as applied to Cyclin Dependent Kinase 2

    Directory of Open Access Journals (Sweden)

    Gu Jenny

    2007-02-01

    Full Text Available Abstract Background The mechanisms underlying protein function and associated conformational change are dominated by a series of local entropy fluctuations affecting the global structure yet are mediated by only a few key residues. Transitional Dynamic Analysis (TDA is a new method to detect these changes in local protein flexibility between different conformations arising from, for example, ligand binding. Additionally, Positional Impact Vertex for Entropy Transfer (PIVET uses TDA to identify important residue contact changes that have a large impact on global fluctuation. We demonstrate the utility of these methods for Cyclin-dependent kinase 2 (CDK2, a system with crystal structures of this protein in multiple functionally relevant conformations and experimental data revealing the importance of local fluctuation changes for protein function. Results TDA and PIVET successfully identified select residues that are responsible for conformation specific regional fluctuation in the activation cycle of Cyclin Dependent Kinase 2 (CDK2. The detected local changes in protein flexibility have been experimentally confirmed to be essential for the regulation and function of the kinase. The methodologies also highlighted possible errors in previous molecular dynamic simulations that need to be resolved in order to understand this key player in cell cycle regulation. Finally, the use of entropy compensation as a possible allosteric mechanism for protein function is reported for CDK2. Conclusion The methodologies embodied in TDA and PIVET provide a quick approach to identify local fluctuation change important for protein function and residue contacts that contributes to these changes. Further, these approaches can be used to check for possible errors in protein dynamic simulations and have the potential to facilitate a better understanding of the contribution of entropy to protein allostery and function.

  17. Multicomponent venom of the spider Cupiennius salei: a bioanalytical investigation applying different strategies.

    Science.gov (United States)

    Trachsel, Christian; Siegemund, Doreen; Kämpfer, Urs; Kopp, Lukas S; Bühr, Claudia; Grossmann, Jonas; Lüthi, Christoph; Cunningham, Monica; Nentwig, Wolfgang; Kuhn-Nentwig, Lucia; Schürch, Stefan; Schaller, Johann

    2012-08-01

    The multicomponent venom of the spider Cupiennius salei was separated by three different chromatographic strategies to facilitate subsequent analysis of peptidic venom components by tandem mass spectrometry (MALDI-TOF-MS and ESI-MS), Edman degradation and amino acid analysis: (a) desalting of the crude venom by RP-HPLC only, (b) chromatographic separation of the crude venom into 42 fractions by RP-HPLC, and (c) multidimensional purification of the crude venom by size exclusion and cation exchange chromatography and RP-HPLC. A total of 286 components were identified in the venom of C. salei by mass spectrometry and the sequence of 49 new peptides was determined de novo by Edman degradation and tandem mass spectrometry; 30 were C-terminally amidated. The novel peptides were assigned to two main groups: (a) short cationic peptides and (b) Cys-containing peptides with the inhibitor cystine knot motif. Bioinformatics revealed a limited number of substantial similarities, namely with the peptides CpTx1 from the spider Cheiracantium punctorium and U3-ctenitoxin-Asp1a from the South American fishing spider (Ancylometes sp.) and with sequences from a Lycosa singoriensis venom gland transcriptome analysis. The results clearly indicate that the quality of the data is strongly dependent on the chosen separation strategy. The combination of orthogonal analytical methods efficiently excludes alkali ion and matrix adducts, provides indispensable information for an unambiguous identification of isomasses, and results in the most comprehensive repertoire of peptides identified in the venom of C. salei so far.

  18. Thermal instability and current-voltage scaling in superconducting fault current limiters

    Energy Technology Data Exchange (ETDEWEB)

    Zeimetz, B [Department of Materials Science and Metallurgy, Cambridge University, Pembroke Street, Cambridge CB1 3QZ (United Kingdom); Tadinada, K [Department of Engineering, Cambridge University, Trumpington Road, Cambridge CB2 1PZ (United Kingdom); Eves, D E [Department of Engineering, Cambridge University, Trumpington Road, Cambridge CB2 1PZ (United Kingdom); Coombs, T A [Department of Engineering, Cambridge University, Trumpington Road, Cambridge CB2 1PZ (United Kingdom); Evetts, J E [Department of Materials Science and Metallurgy, Cambridge University, Pembroke Street, Cambridge CB1 3QZ (United Kingdom); Campbell, A M [Department of Engineering, Cambridge University, Trumpington Road, Cambridge CB2 1PZ (United Kingdom)

    2004-04-01

    We have developed a computer model for the simulation of resistive superconducting fault current limiters in three dimensions. The program calculates the electromagnetic and thermal response of a superconductor to a time-dependent overload voltage, with different possible cooling conditions for the surfaces, and locally variable superconducting and thermal properties. We find that the cryogen boil-off parameters critically influence the stability of a limiter. The recovery time after a fault increases strongly with thickness. Above a critical thickness, the temperature is unstable even for a small applied AC voltage. The maximum voltage and maximum current during a short fault are correlated by a simple exponential law.

  19. Admittance Spectroscopy in CZTSSe: Metastability Behavior and Voltage Dependent Defect Study

    Energy Technology Data Exchange (ETDEWEB)

    Koeper, Mark J.; Hages, Charles J.; Li, Jian V.; Levi, Dean; Agrawal, Rakesh

    2016-11-21

    Admittance spectroscopy has been performed on a CZTSSe device with a carrier injection pretreatment and under electronically relaxed conditions to demonstrate metastability behavior. We show that the measurements with the carrier injection pretreatment demonstrate two admittance signatures while the relaxed measurement demonstrates only one admittance signature with a different activation energy. Additionally, voltage dependent admittance spectroscopy was performed using the carrier injection pretreatment method at each of the applied voltage bias. The activation energies of the two admittance signatures were calculated and are shown to be independent of the voltage bias.

  20. Experimental investigation of SDBD plasma actuator driven by AC high voltage with a superimposed positive pulse bias voltage

    Science.gov (United States)

    Qi, Xiao-Hua; Yan, Hui-Jie; Yang, Liang; Hua, Yue; Ren, Chun-Sheng

    2017-08-01

    In this work, a driven voltage consisting of AC high voltage with a superimposed positive pulse bias voltage ("AC+ Positive pulse bias" voltage) is adopted to study the performance of a surface dielectric barrier discharge plasma actuator under atmospheric conditions. To compare the performance of the actuator driven by single-AC voltage and "AC+ Positive pulse bias" voltage, the actuator-induced thrust force and power consumption are measured as a function of the applied AC voltage, and the measured results indicate that the thrust force can be promoted significantly after superimposing the positive pulse bias voltage. The physical mechanism behind the thrust force changes is analyzed by measuring the optical properties, electrical characteristics, and surface potential distribution. Experimental results indicate that the glow-like discharge in the AC voltage half-cycle, next to the cycle where a bias voltage pulse has been applied, is enhanced after applying the positive pulse bias voltage, and this perhaps is the main reason for the thrust force increase. Moreover, surface potential measurement results reveal that the spatial electric field formed by the surface charge accumulation after positive pulse discharge can significantly affect the applied external electric field, and this perhaps can be responsible for the experimental phenomenon that the decrease of thrust force is delayed by pulse bias voltage action after the filament discharge occurs in the glow-like discharge region. The schlieren images further verify that the actuator-induced airflow velocity increases with the positive pulse voltage.

  1. Variability in micronucleus induction with different mutagens applied to several species of fish

    Directory of Open Access Journals (Sweden)

    Cesar Koppe Grisolia

    2000-03-01

    Full Text Available Fish are often used for screening genotoxicity of water. For such programs, a knowledge of the sensitivity to clastogens, spontaneous micronucleus frequency and cell cycle kinetics of the target tissue is necessary. To investigate the pattern of inter-specific sensitivity to micronucleus induction three species of fish, Tilapia rendalli, Oreochromis niloticus and Cyprinus carpio, were exposed to the clastogens bleomycin (BLM, cyclophosphamide (CP, 5-fluorouracil (5-FU, and mitomycin C (MMC. The binucleate/mononucleate ratio in peripheral erythrocytes exposed to cytochalasin B was also used to evaluate the time-dependent response of micronucleus formation during hematopoesis in the kidney and the micronucleus peak in peripheral erythrocytes. Micronucleus frequencies induced by CP were significantly greater than their respective controls for the three fish species throughout all treatment periods. During the whole evaluation period (30 days CP was also the most effective clastogen. In general, until the 14th day of evaluation period T. rendalii was the most sensitive species to clastogens. No difference in micronucleus frequencies among species was observed in the 4th evaluation (at the 30th day. A micronucleus peak was observed at the 7th day after treatment. After the 14th day the frequencies were stabilized. The cytochalasin B experiment was carried out to demonstrate that micronuclei induced in the young kidney erythrocyte cells were detected in the circulating blood 2-4 days later.Este estudo fez uma avaliação da indução de micronúcleos em eritrócitos de sangue periférico de peixes Tilapia rendalli, Oreochromis niloticus e Cyprinus carpio após o tratamento com mitomicina C, ciclofosfamida, 5-fluorouracil e bleomicina. Foram colhidas amostras periódicas de sangue com 2, 7, 14 e 30 dias após o tratamento único. Os tratamentos com citocalasina B tiveram como objetivo analisar as proporções entre células binucleadas

  2. Research on Topologies of Voltage Balancers Applied in DC Micro-grid%面向直流微电网的电压平衡器拓扑结构研究

    Institute of Scientific and Technical Information of China (English)

    汪飞; 雷志方; 徐新蔚

    2016-01-01

    As an energy-saving efficient DC distribution form, bipolar DC bus has a great advantage in the low voltage DC power system, in which the voltage balancer plays an important role. A voltage balancer, on the one hand, achieves a conversion from unipolar bus to bipolar bus, and it also solves the problem of power imbalance between positive and negative polarity bus. This paper analyzed the existing research results of voltage balancer topologies in detail, and summed up the method of forming voltage balancers. Furthermore, new topologies were proposed, such as Cuk, Super-Sepic/Zeta and interleaved Buck/Boost type voltage balancers. Finally, the correctness of the proposed topologies were verified by simulations, and two phase interleaved Buck/Boost type voltage balancer experimental platform was used to verify its good bipolar bus distribution effect and the fine current sharing and dynamic characteristic of interleaved average current control strategy.%作为一种节能高效的直流配电形式,双极性直流母线配电在低压直流配电系统中具有较大的应用优势,电压平衡器在其中扮演着重要的角色。电压平衡器一方面实现了单极性配电向双极性配电的转化,另一方面也解决了正负极性母线间的功率不平衡问题。该文首先分析了现有的电压平衡器拓扑结构研究成果;然后归纳出了电压平衡器的形成方法,提出了Cuk型电压平衡器、Super-Sepic/Zeta型电压平衡器和交错并联 Buck/Boost 型电压平衡器;最后通过仿真验证了所提出拓扑结构的正确性,通过两相交错并联Buck/Boost型电压平衡器实验平台验证了所提出的交错采样交错平均电流控制策略良好的均流效果和动态响应速度以及平衡器优异的双极性母线配电效果。

  3. Selective Dirac voltage engineering of individual graphene field-effect transistors for digital inverter and frequency multiplier integrations

    Science.gov (United States)

    Sul, Onejae; Kim, Kyumin; Jung, Yungwoo; Choi, Eunsuk; Lee, Seung-Beck

    2017-09-01

    The ambipolar band structure of graphene presents unique opportunities for novel electronic device applications. A cycle of gate voltage sweep in a conventional graphene transistor produces a frequency-doubled output current. To increase the frequency further, we used various graphene doping control techniques to produce Dirac voltage engineered graphene channels. The various surface treatments and substrate conditions produced differently doped graphene channels that were integrated on a single substrate and multiple Dirac voltages were observed by applying a single gate voltage sweep. We applied the Dirac voltage engineering techniques to graphene field-effect transistors on a single chip for the fabrication of a frequency multiplier and a logic inverter demonstrating analog and digital circuit application possibilities.

  4. Gender Differences in the Use of Hedges And First Person Pronouns in Research Articles of Applied Linguistics and Chemistry

    Directory of Open Access Journals (Sweden)

    Fatemeh Mirzapour

    2016-11-01

    Full Text Available Differences in the way that males and females use language have been of interest in the study of discourse. This study is an attempt to examine whether men and women differ with respect to the use of hedges and first person pronouns in research articles of two disciplines of Applied Linguistics and Chemistry. Based on a corpus of sixty research articles, the overall  categorical distribution of hedging devices and first person pronouns were calculated in research articles. The results indicate that hedges and first person plural pronouns are used in Applied Linguistics articles more frequently than Chemistry articles. Moreover, females use hedges more than males in both disciplines but males use first person plural pronoun more than females in both disciplines. These findings may have some implications for the teaching of academic writing to EFL students.              Keywords: Gender, Hedges, Person Pronoun, Research Articles

  5. Inductive voltage divider modeling in Matlab

    Science.gov (United States)

    Andreev, S. A.; Kim, V. L.

    2017-01-01

    Inductive voltage dividers have the most appropriate metrological characteristics on alternative current and are widely used for converting physical signals. The model of a double-decade inductive voltage divider was designed with the help of Matlab/Simulink. The first decade is an inductive voltage divider with balanced winding, the second decade is a single-stage inductive voltage divider. In the paper, a new transfer function algorithm was given. The study shows errors and differences that appeared between the third degree reduced model and a twenty degree unreduced model. The obtained results of amplitude error differ no more than by 7 % between the reduced and unreduced model.

  6. Automated Voltage Control in LHCb

    CERN Document Server

    Granado Cardoso, L; Jacobsson, R

    2011-01-01

    LHCb is one of the 4 LHC experiments. In order to ensure the safety of the detector and to maximize efficiency, LHCb needs to coordinate its own operations, in particular the voltage configuration of the different subdetectors, according to the accelerator status. A control software has been developed for this purpose, based on the Finite State Machine toolkit and the SCADA system used for control throughout LHCb (and the other LHC experiments). This software permits to efficiently drive both the Low Voltage (LV) and High Voltage (HV) systems of the 10 different sub-detectors that constitute LHCb, setting each sub-system to the required voltage (easily configurable at run-time) based on the accelerator state. The control software is also responsible for monitoring the state of the Sub-detector voltages and adding it to the event data in the form of status-bits. Safe and yet flexible operation of the LHCb detector has been obtained and automatic actions, triggered by the state changes of the ...

  7. Comparative analysis of two different models of swimming applied to pregnant rats born small for pregnant age

    OpenAIRE

    CORVINO,SILVANA B.; Damasceno, Débora C; Yuri K Sinzato; NETTO,ALINE O.; MACEDO,NATHÁLIA C.D.; Zambrano, Elena; Volpato, Gustavo T

    2017-01-01

    ABSTRACT The aim of this study was to compare two models of swimming applied to pregnant rats born small for pregnancy age (SPA). Diabetes was chemically induced in adult female rats to develop an inadequate intrauterine environment, leading to birth of a SPA offspring. In adulthood, the female SPA rats were mated and submitted to different swimming programs. The exercise program 1 (Ex1) consisted of swimming for 15 minutes, followed by 15 minutes of rest and another 15 minutes of swimming, 3...

  8. Characterisation of the VELO High Voltage System

    CERN Document Server

    Rakotomiaramanana, B; Eklund, L

    2008-01-01

    The high voltage system supplies the bias voltage to the 88 silicon sensors which comprise the LHCb Vertex Locator (VELO). This note describes the results of the tests which have been performed on the hardware of the high voltage system of the VELO. Each individual test detailed in this note corresponds to a specific requirement of the system. These requirements arise primarily from ensuring the safety of the silicon sensors and the quality of the data taken from the VELO modules. The tests performed are in four categories: normal operation of the high voltage system; vercation of its stability under operation; discussion of its behaviour in failure modes; and details of operation at low voltage. Noteworthy issues, identified through the tests, include the behaviour of the high voltage modules at voltages below 9V, the current limit that can be applied during ramping of the voltage, and the speed with which the voltage is cut during failures of the system. The results of these tests provide high confidence th...

  9. Characterisation of the VELO High Voltage System

    CERN Document Server

    Rakotomiaramanana, B; Parkes, C; Eklund, L

    2008-01-01

    The high voltage system supplies the bias voltage to the 88 silicon sensors which comprise the LHCb Vertex Locator (VELO). This note describes the results of the tests which have been performed on the hardware of the high voltage system of the VELO. Each individual test detailed in this note corresponds to a specific requirement of the system. These requirements arise primarily from ensuring the safety of the silicon sensors and the quality of the data taken from the VELO modules. The tests performed are in four categories: normal operation of the high voltage system; verification of its stability under operation; discussion of its behaviour in failure modes; and details of operation at low voltage. Noteworthy issues, identified through the tests, include the behaviour of the high voltage modules at voltages below 9V, the current limit that can be applied during ramping of the voltage, and the speed with which the voltage is cut during failures of the system. The results of these tests provide high confidence...

  10. Analysis of loss distribution of Conventional Boost, Z-source and Y-source Converters for wide power and voltage range

    DEFF Research Database (Denmark)

    Gadalla, Brwene Salah Abdelkarim; Schaltz, Erik; Siwakoti, Yam Prasad

    2017-01-01

    Boost converters are needed in many applications which require the output voltage to be higher than the input voltage. Recently, boost type converters have been applied for industrial applications, and hence it has become an interesting topic of research. Many researchers proposed different imped...

  11. Analysis of loss distribution of Conventional Boost, Z-source and Y-source Converters for wide power and voltage range

    DEFF Research Database (Denmark)

    Gadalla, Brwene Salah Abdelkarim; Schaltz, Erik; Siwakoti, Yam Prasad

    2017-01-01

    Boost converters are needed in many applications which require the output voltage to be higher than the input voltage. Recently, boost type converters have been applied for industrial applications, and hence it has become an interesting topic of research. Many researchers proposed different imped...

  12. Study on Optimization Strategy for Voltage and Reactive Power Control of Wind Farm

    Science.gov (United States)

    Lu, Q.; Shi, L.; Chen, N.

    A method for calculating reactive power limit of wind farm comprised of doubly-fed induction generators (DFIG) is proposed. The reactive power limit of wind farm is the sum of reactive power limit of DFIGs which is calculated by the method considering static stability margin. Based on this, reactive power control of wind farm is discussed and proposed. The proposed reactive power control is divided into different control modes according to power factor of high voltage side in wind farm substation and voltage of low voltage side in point of interconnection(POI). In different control modes, different control objects are applied on reactive power regulation. After reactive power regulation is finished, some reactive power of wind farm should be released. At last, numerical test system is established, the result shows that the proposed method is effective to support voltage of POI

  13. Unbalanced Voltage Compensation in Low Voltage Residential AC Grids

    DEFF Research Database (Denmark)

    Trintis, Ionut; Douglass, Philip; Munk-Nielsen, Stig

    2016-01-01

    This paper describes the design and test of a control algorithm for active front-end rectifiers that draw power from a residential AC grid to feed heat pump loads. The control algorithm is able to control the phase to neutral or phase to phase RMS voltages at the point of common coupling....... The voltage control was evaluated with either active or reactive independent phase load current control. The control performance in field operation in a residential grid situated in Bornholm, Denmark was investigated for different use cases....

  14. Implementation of Dynamic Voltage Restorer for Mitigation of Voltage Sag

    Directory of Open Access Journals (Sweden)

    K.Vinod Kumar

    2013-07-01

    Full Text Available Power quality is one of major concerns in the present. It has become important, especially with the introduction of sophisticated devices, whose performance is very sensitive to the quality of power supply. The dynamic voltage restorer (DVR is one of the modern devices used in distribution systems to improve the power quality. In this paper, emergency control in distribution systems is discussed by using the proposed multifunctional DVR control strategy.Also, themultiloop controller using the Posicast and P+Resonant controllers is proposed in order to improve the transient response and eliminate the steady state error in DVR response,respectively.The proposed process is applied to some riots in load voltage effected by induction motors starting, and a three-phase short circuit fault. The three-phase short circuits, and the large induction motors are suddenly started then voltage sags areoccurred.The innovation here is that by using the Multifunctional Dynamic Voltage Restorer, improve the power quality in distribution side. Simulation results show the capability of the DVR to control the emergency conditions of the distribution systems by using MATLAB/Simulink software.

  15. Mitigation Voltage Sag in Power System by Static Synchronous Compensator

    Directory of Open Access Journals (Sweden)

    Prechanon Kumkratug

    2010-01-01

    Full Text Available Problem statement: The disturbance in power system is unavoidable situation. It cause in voltage sag in power system. Approach: This study applied the STATCOM to mitigate voltage of the system. The mathematical model of power system equipped with a STATCOM is systematically derived. The presented mathematical model is shown how it effects on voltage sag improvement. The simulation results are tested on a Single Machine Infinite bus. The proposed method is equipped in sample system with severe disturbance. The variation voltage of the system without and with a STATCOM is plotted and compared. Results: It was found that the system without a STATCOM has high voltage variation especially voltage sags whereas with a STATCOM the system voltage has small voltage sages. Conclusion: From the simulation results, the STATCOM can mitigate voltage of power system.

  16. Unified Power Quality Conditioner for voltage and current compensation

    OpenAIRE

    P.Annapandi; Dr.M.Rajaram

    2012-01-01

    This paper deals with a Unified Power Quality Conditioner (UPQC) for load balancing, power factorcorrection, voltage regulation, voltage and current harmonics mitigation, mitigation of voltage sag, swelland voltage dip in a three-phase three-wire distribution system for different combinations of linear and nonlinear loads.The unified power quality conditioner (UPQC) is a combination of back to back connected shunt and series active power filters (APFs) to a common DC link voltage, which compe...

  17. New longitudinal differential protection scheme for four-circuit transmission line with different voltage grades%不同电压等级的四回线的纵联差动保护方案

    Institute of Scientific and Technical Information of China (English)

    陈金熠; 范春菊; 刘玲

    2011-01-01

    To solve the problem that the traditional longitudinal differential protection used in four-circuit transmission line on the same pole with different levels will be seriously affected by coupling inductance, a new longitudinal differential protection scheme based on inverse-sequence negative sequence difference current is proposed. Four-circuit transmission lines with different voltage grades generally consist of two double circuit transmission lines at the same tower. However, when line parameters are symmetry, the inverted sequence current is zero when the system operates normally or external faults occur. Once internal faults occur, there is inverted current in the transmission line, and the sum of inverted current at both sides is large, so the differential protection based on inverted current can operate correctly. For this method, the reliability and sensitivity under big fault resistance can be kept. And it will not be affected by capacitive current when it is applied to the main protection of four-circuit transmission line with different voltage grades. The theoretical analysis and EMTP simulation results show that the proposed principle is correct and reliable.%为克服传统纵联差动保护运用在不同电压等级的同杆四回线中容易受到耦合电感的影响,提出了基于反序负序差电流的纵联差动保护方案.不同电压等级的四回线由两个不同电压的等级的同杆双回线构成.对于同杆双回线路,当线路参数完全对称时,系统正常运行或是外部故障时,反向电流分量为零;而当双回线内部故障时,反向环流量存在于双回线的内部,双回线两侧反向电流之和比较大,可以构成基于反向环流量的纵联差动保护.该保护方案不仅可以避开电容电流对于差动保护的影响,而且有较强的抗过渡电阻能力.将该保护方案应用到不同电压等级的四回线的主保护中,保护性能优越,不仅可以可靠动作,还避免了电容

  18. Energy reduction through voltage scaling and lightweight checking

    Science.gov (United States)

    Kadric, Edin

    As the semiconductor roadmap reaches smaller feature sizes and the end of Dennard Scaling, design goals change, and managing the power envelope often dominates delay minimization. Voltage scaling remains a powerful tool to reduce energy. We find that it results in about 60% geomean energy reduction on top of other common low-energy optimizations with 22nm CMOS technology. However, when voltage is reduced, it becomes easier for noise and particle strikes to upset a node, potentially causing Silent Data Corruption (SDC). The 60% energy reduction, therefore, comes with a significant drop in reliability. Duplication with checking and triple-modular redundancy are traditional approaches used to combat transient errors, but spending 2--3x the energy for redundant computation can diminish or reverse the benefits of voltage scaling. As an alternative, we explore the opportunity to use checking operations that are cheaper than the base computation they are guarding. We devise a classification system for applications and their lightweight checking characteristics. In particular, we identify and evaluate the effectiveness of lightweight checks in a broad set of common tasks in scientific computing and signal processing. We find that the lightweight checks cost only a fraction of the base computation (0-25%) and allow us to recover the reliability losses from voltage scaling. Overall, we show about 50% net energy reduction without compromising reliability compared to operation at the nominal voltage. We use FPGAs (Field-Programmable Gate Arrays) in our work, although the same ideas can be applied to different systems. On top of voltage scaling, we explore other common low-energy techniques for FPGAs: transmission gates, gate boosting, power gating, low-leakage (high-Vth) processes, and dual-V dd architectures. We do not scale voltage for memories, so lower voltages help us reduce logic and interconnect energy, but not memory energy. At lower voltages, memories become dominant

  19. Voltage stability in low voltage microgrids in aspects of active and reactive power demand

    Directory of Open Access Journals (Sweden)

    Parol Mirosław

    2016-03-01

    Full Text Available Low voltage microgrids are autonomous subsystems, in which generation, storage and power and electrical energy consumption appear. In the paper the main attention has been paid to the voltage stability issue in low voltage microgrid for different variants of its operation. In the introduction a notion of microgrid has been presented, and also the issue of influence of active and reactive power balance on node voltage level has been described. Then description of voltage stability issue has been presented. The conditions of voltage stability and indicators used to determine voltage stability margin in the microgrid have been described. Description of the low voltage test microgrid, as well as research methodology along with definition of considered variants of its operation have been presented further. The results of exemplary calculations carried out for the daily changes in node load of the active and reactive power, i.e. the voltage and the voltage stability margin indexes in nodes have been presented. Furthermore, the changes of voltage stability margin indexes depending on the variant of the microgrid operation have been presented. Summary and formulation of conclusions related to the issue of voltage stability in microgrids have been included at the end of the paper.

  20. 2.3-MW Medium-Voltage, Three-Level Wind Energy Inverter Applying a Unique Bus Structure and 4.5-kV Si/SiC Hybrid Isolated Power Modules: Preprint

    Energy Technology Data Exchange (ETDEWEB)

    Erdman, W.; Keller, J.; Grider, D.; VanBrunt, E.

    2014-11-01

    A high-efficiency, 2.3-MW, medium-voltage, three-level inverter utilizing 4.5-kV Si/SiC (silicon carbide) hybrid modules for wind energy applications is discussed. The inverter addresses recent trends in siting the inverter within the base of multimegawatt turbine towers. A simplified split, three-layer laminated bus structure that maintains low parasitic inductances is introduced along with a low-voltage, high-current test method for determining these inductances. Feed-thru bushings, edge fill methods, and other design features of the laminated bus structure provide voltage isolation that is consistent with the 10.4-kV module isolation levels. Inverter efficiency improvement is a result of the (essential) elimination of the reverse recovery charge present in 4.5-kV Si PIN diodes, which can produce a significant reduction in diode turn-off losses as well as insulated-gate bipolar transistor (IGBT) turn-on losses. The hybrid modules are supplied in industry-standard 140 mm x 130 mm and 190 mm x 130 mm packages to demonstrate direct module substitution into existing inverter designs. A focus on laminated bus/capacitor-bank/module subassembly level switching performance is presented.

  1. KEY COMPARISONS: Final report: SIM regional comparison of ac-dc voltage transfer difference (SIM.EM.K6a, SIM.EM-K9 and SIM.EM-K11)

    Science.gov (United States)

    Campos, Sara; Filipski, Piotr; Izquierdo, Daniel; Afonso, Edson; Landim, Régis P.; Di Lillo, Lucas; Lipe, Thomas

    2009-01-01

    Three comparisons of ac-dc voltage transfer difference held from January to December 2004 are reported. Six NMIs in the SIM region took part: NRC (Canada), NIST (United States of America), CENAM (Mexico), INTI (Argentina), UTE (Uruguay) and INMETRO (Brazil). The comparisons were proposed to assess the measurement capabilities in ac-dc voltage transfer difference of the NMIs in the SIM region. The test points were selected to link the results with the equivalent CCEM Key Comparisons, through three NMIs participating in both SIM and CCEM key comparisons. Additionally, a SIM.EM-Supplementary comparison was proposed, in support of the SIM NMIs' power/energy meter calibration capabilities. One technical protocol and one travelling standard were used, to economize on time and resources. The report shows the degree of equivalence in the SIM region and also the degree of equivalence with the corresponding CCEM reference value. The results of all participants support the values and uncertainties of the applicable CMC entries for ac-dc voltage transfer difference in the Key Comparison Database held at the BIPM. Main text. To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/. The final report has been peer-reviewed and approved for publication by the CCEM, according to the provisions of the CIPM Mutual Recognition Arrangement (MRA).

  2. Stray voltage mitigation

    Energy Technology Data Exchange (ETDEWEB)

    Jamali, B.; Piercy, R.; Dick, P. [Kinetrics Inc., Toronto, ON (Canada). Transmission and Distribution Technologies

    2008-04-09

    This report discussed issues related to farm stray voltage and evaluated mitigation strategies and costs for limiting voltage to farms. A 3-phase, 3-wire system with no neutral ground was used throughout North America before the 1930s. Transformers were connected phase to phase without any electrical connection between the primary and secondary sides of the transformers. Distribution voltage levels were then increased and multi-grounded neutral wires were added. The earth now forms a parallel return path for the neutral current that allows part of the neutral current to flow continuously through the earth. The arrangement is responsible for causing stray voltage. Stray voltage causes uneven milk production, increased incidences of mastitis, and can create a reluctance to drink water amongst cows when stray voltages are present. Off-farm sources of stray voltage include phase unbalances, undersized neutral wire, and high resistance splices on the neutral wire. Mitigation strategies for reducing stray voltage include phase balancing; conversion from single to 3-phase; increasing distribution voltage levels, and changing pole configurations. 22 refs., 5 tabs., 13 figs.

  3. High voltage engineering

    CERN Document Server

    Rizk, Farouk AM

    2014-01-01

    Inspired by a new revival of worldwide interest in extra-high-voltage (EHV) and ultra-high-voltage (UHV) transmission, High Voltage Engineering merges the latest research with the extensive experience of the best in the field to deliver a comprehensive treatment of electrical insulation systems for the next generation of utility engineers and electric power professionals. The book offers extensive coverage of the physical basis of high-voltage engineering, from insulation stress and strength to lightning attachment and protection and beyond. Presenting information critical to the design, selec

  4. High voltage test techniques

    CERN Document Server

    Kind, Dieter

    2001-01-01

    The second edition of High Voltage Test Techniques has been completely revised. The present revision takes into account the latest international developments in High Voltage and Measurement technology, making it an essential reference for engineers in the testing field.High Voltage Technology belongs to the traditional area of Electrical Engineering. However, this is not to say that the area has stood still. New insulating materials, computing methods and voltage levels repeatedly pose new problems or open up methods of solution; electromagnetic compatibility (EMC) or components and systems al

  5. Mitigation of Unbalanced Voltage Sags and Voltage Unbalance in CIGRE Low Voltage Distribution Network

    OpenAIRE

    Mustafa, Ghullam; Bak-Jensen, Birgitte; Mahat, Pukar; Cecati, Carlo

    2013-01-01

    Any problem with voltage in a power network is undesirable as it aggravates the quality of the power. Power electronic devices such as Voltage Source Converter (VSC) based Static Synchronous Compensator (STATCOM) etc. can be used to mitigate the voltage problems in the distribution system. The voltage problems dealt with in this paper are to show how to mitigate unbalanced voltage sags and voltage unbalance in the CIGRE Low Voltage (LV) test network and net-works like this. The voltage unbala...

  6. Estimation of the light output power and efficiency of Xe barrier discharge excimer lamps using a one-dimensional fluid model for various voltage waveforms

    Science.gov (United States)

    Oda, Akinori; Sugawara, Hirotake; Sakai, Yosuke; Akashi, Haruaki

    2000-06-01

    Xe dielectric barrier discharges at different gap lengths under applied pulse voltages with trapezoidal and sinusoidal waveforms were simulated using a self-consistent one-dimensional fluid model. In both waveforms, the light output power depended not only on the amplitude of voltage waveforms but also on the discharge gap length. At the narrower discharge gap, the light output efficiency was improved by increasing the time gradient of the applied voltage when the trapezoidal pulse is applied, and by decreasing the duty ratio in the sinusoidal case. In the present simulation, we adopted a fast numerical method for calculation of electric field introducing an exact expression of the discharge current.

  7. A comparative study of different aspects of manipulating ratio spectra applied for ternary mixtures: derivative spectrophotometry versus wavelet transform.

    Science.gov (United States)

    Salem, Hesham; Lotfy, Hayam M; Hassan, Nagiba Y; El-Zeiny, Mohamed B; Saleh, Sarah S

    2015-01-25

    This work represents a comparative study of different aspects of manipulating ratio spectra, which are: double divisor ratio spectra derivative (DR-DD), area under curve of derivative ratio (DR-AUC) and its novel approach, namely area under the curve correction method (AUCCM) applied for overlapped spectra; successive derivative of ratio spectra (SDR) and continuous wavelet transform (CWT) methods. The proposed methods represent different aspects of manipulating ratio spectra of the ternary mixture of Ofloxacin (OFX), Prednisolone acetate (PA) and Tetryzoline HCl (TZH) combined in eye drops in the presence of benzalkonium chloride as a preservative. The proposed methods were checked using laboratory-prepared mixtures and were successfully applied for the analysis of pharmaceutical formulation containing the cited drugs. The proposed methods were validated according to the ICH guidelines. A comparative study was conducted between those methods regarding simplicity, limitation and sensitivity. The obtained results were statistically compared with those obtained from the reported HPLC method, showing no significant difference with respect to accuracy and precision.

  8. Programmable high voltage power supply with regulation confined to the high voltage section

    Science.gov (United States)

    Castell, Karen D. (Inventor); Ruitberg, Arthur P. (Inventor)

    1994-01-01

    A high voltage power supply in a dc-dc converter configuration includes a pre-regulator which filters and regulates the dc input and drives an oscillator which applies, in turn, a low voltage ac signal to the low side of a step-up high voltage transformer. The high voltage side of the transformer drives a voltage multiplier which provides a stepped up dc voltage to an output filter. The output voltage is sensed by a feedback network which then controls a regulator. Both the input and output of the regulator are on the high voltage side, avoiding isolation problems. The regulator furnishes a portion of the drive to the voltage multiplier, avoiding having a regulator in series with the load with its attendant, relatively high power losses. This power supply is highly regulated, has low power consumption, a low parts count and may be manufactured at low cost. The power supply has a programmability feature that allows for the selection of a large range of output voltages.

  9. Transformerless DC-DC Converter Using Cockcroft-Walton Voltage Multiplier to Obtain High DC Voltage

    Directory of Open Access Journals (Sweden)

    Meghana G Naik,

    2014-11-01

    Full Text Available In the present scenario the use of transformer for high voltages in converter circuit reduces the overall operating efficiency due to leakage inductance and use of transformer also increases the operational cost. . Therefore the proposed system is implemented with transformer less DC-DC converter so as to obtain high DC voltage with the use of nine stage Cockcroft-Walton (CW voltage multiplier. The proposed converter operates in CCM (continuous conduction mode, so that the converter switch stress, the switching losses are reduced. The DC voltage at the input of the proposed model is low and is boosted up by boost inductor (Ls in DC-DC converter stage and performs inverter operation. The number of stages in CW-voltage multiplier circuit is applied with low input pulsating DC (AC Voltage voltage where it is getting converted to high DC output voltage. The proposed converter switches operates at two independent frequencies, modulating (fsm andalternating (fsc frequency. The fsm operates at higher frequency of the output while the fsc operates at lower frequency of the desired output voltage ripple and the output ripples can be adjusted by the switch Sc1 and Sc2. The regulation of the output voltage is achieved by controlling the Duty ratio.The simulation is carried over by the MATLABSIMULINK.

  10. Low-Voltage Continuous Electrospinning Patterning.

    Science.gov (United States)

    Li, Xia; Li, Zhaoying; Wang, Liyun; Ma, Guokun; Meng, Fanlong; Pritchard, Robyn H; Gill, Elisabeth L; Liu, Ye; Huang, Yan Yan Shery

    2016-11-30

    Electrospinning is a versatile technique for the construction of microfibrous and nanofibrous structures with considerable potential in applications ranging from textile manufacturing to tissue engineering scaffolds. In the simplest form, electrospinning uses a high voltage of tens of thousands volts to draw out ultrafine polymer fibers over a large distance. However, the high voltage limits the flexible combination of material selection, deposition substrate, and control of patterns. Prior studies show that by performing electrospinning with a well-defined "near-field" condition, the operation voltage can be decreased to the kilovolt range, and further enable more precise patterning of fibril structures on a planar surface. In this work, by using solution dependent "initiators", we demonstrate a further lowering of voltage with an ultralow voltage continuous electrospinning patterning (LEP) technique, which reduces the applied voltage threshold to as low as 50 V, simultaneously permitting direct fiber patterning. The versatility of LEP is shown using a wide range of combination of polymer and solvent systems for thermoplastics and biopolymers. Novel functionalities are also incorporated when a low voltage mode is used in place of a high voltage mode, such as direct printing of living bacteria; the construction of suspended single fibers and membrane networks. The LEP technique reported here should open up new avenues in the patterning of bioelements and free-form nano- to microscale fibrous structures.

  11. Voltage controlled spintronics device for logic applications.

    Energy Technology Data Exchange (ETDEWEB)

    Bader, S. D.; You, C.-Y.

    1999-09-03

    We consider logic device concepts based on our previously proposed spintronics device element whose magnetization orientation is controlled by application of a bias voltage instead of a magnetic field. The basic building block is the voltage-controlled rotation (VCR) element that consists of a four-layer structure--two ferromagnetic layers separated by both nanometer-thick insulator and metallic spacer layers. The interlayer exchange coupling between the two ferromagnetic layers oscillates as a function of applied voltage. We illustrate transistor-like concepts and re-programmable logic gates based on VCR elements.

  12. Voltage verification unit

    Science.gov (United States)

    Martin, Edward J.

    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.

  13. Research Progress of Inverse Power Law Applied in Lifetime Design of High Voltage Cable%反幂定律应用于高压电缆寿命设计的研究进展

    Institute of Scientific and Technical Information of China (English)

    廖雁群; 冯冰; 罗潘; 张连杰; 卢志华; 徐阳

    2016-01-01

    本文回顾了反幂定律的发展过程,用Eyring公式对反幂定律的正确性进行了理论解释,总结了反幂定律在确定高压电缆绝缘厚度和在电缆E-t寿命曲线中的应用,给出了温度修正的电老化寿命模型,阐述了温度在高压电缆寿命设计中的重要性。%The development process of the inverse power law was reviewed, and the correctness of inverse power law was theoretical explained with the Eyring equation. The application of the inverse power law in determining the thickness of high voltage cable insulation and the application in the life curves of cable were summarized. Finally, this paper presented the electrical ageing lifetime model revised by temperature and emphasized the importance of temperature in the lifetime design of high voltage cable.

  14. Simplification and shift in cognition of political difference: applying the geometric modeling to the analysis of semantic similarity judgment.

    Science.gov (United States)

    Kato, Junko; Okada, Kensuke

    2011-01-01

    Perceiving differences by means of spatial analogies is intrinsic to human cognition. Multi-dimensional scaling (MDS) analysis based on Minkowski geometry has been used primarily on data on sensory similarity judgments, leaving judgments on abstractive differences unanalyzed. Indeed, analysts have failed to find appropriate experimental or real-life data in this regard. Our MDS analysis used survey data on political scientists' judgments of the similarities and differences between political positions expressed in terms of distance. Both distance smoothing and majorization techniques were applied to a three-way dataset of similarity judgments provided by at least seven experts on at least five parties' positions on at least seven policies (i.e., originally yielding 245 dimensions) to substantially reduce the risk of local minima. The analysis found two dimensions, which were sufficient for mapping differences, and fit the city-block dimensions better than the Euclidean metric in all datasets obtained from 13 countries. Most city-block dimensions were highly correlated with the simplified criterion (i.e., the left-right ideology) for differences that are actually used in real politics. The isometry of the city-block and dominance metrics in two-dimensional space carries further implications. More specifically, individuals may pay attention to two dimensions (if represented in the city-block metric) or focus on a single dimension (if represented in the dominance metric) when judging differences between the same objects. Switching between metrics may be expected to occur during cognitive processing as frequently as the apparent discontinuities and shifts in human attention that may underlie changing judgments in real situations occur. Consequently, the result has extended strong support for the validity of the geometric models to represent an important social cognition, i.e., the one of political differences, which is deeply rooted in human nature.

  15. [Effects of applying different kind fertilizers on enzyme activities related to carbon, nitrogen, and phosphorus cycles in reddish paddy soil].

    Science.gov (United States)

    Xu, Li-Li; Wang, Qiu-Bing; Zhang, Xin-Yu; Sun, Xiao-Min; Dai, Xiao-Qin; Yang, Feng-Ting; Bu, Jin-Feng; Wang, Hui-min

    2013-04-01

    Based on the long-term fixed position experimental data from Qianyanzhou Ecological Experiment Station, Chinese Academy of Sciences in 1998, this paper analyzed the effects of applying different kind fertilizers (straw, ST; pig manure, OM; and chemical fertilizer, NPK) on the nutrients (C, N, and P) status and the activities of related enzymes ( beta-1,4-glucosidase, betaG; beta-1,4-N-acetylglucosaminidase, NAG; L-leucine aminopeptidase, LAP; and acid phosphatase, AP) in reddish paddy soil. With the application of OM, the activities of soil betaG, NAG, and LAP increased significantly, as compared with other treatments, and were 1.4, 2. 6, and 1.9 times higher than the control (CK) , respectively. Applying OM also improved the ratio of soil organic carbon to total nitrogen (C/N), but decreased the soil betaG/(NAG+LAP) ratio, suggesting that pig manure could benefit the degradation of soil cellulose and the accumulation of soil organic carbon. Applying NPK increased the activities of soil betaG, NAG, and LAP, but decreased the AP activity, with a decrement of 34% as compared with CK. Under the application of NPK, the soilbetaG/AP and (NAG+ LAP)/AP ratios increased, but the ratios of soil organic carbon to total phosphorus (C/P) and of soil total nitrogen to total phosphorus (N/P) decreased, indicating that chemical fertilizers could induce the accumulation of soil inorganic phosphorus, and inhibit the microbial functions of degrading polysaccharides and phosphate phospholipids.

  16. Assessment of different doses of N applied to a melon crop in the quality of groundwater: environmental impact indexes.

    Science.gov (United States)

    Castellanos, M. T.; Cartagena, M. C.; Ribas, F.; Cabello, M. J.; Arce, A.; Tarquis, A. M.

    2010-05-01

    Provided that the intensive use of N in agricultural systems has negatively impacted environmental quality, because a higher fertilization requirements of the crop to make the nitrate leached into the aquifer contaminating, as well as increasing their presence on the ground resulting in a time of intercropping nitrates washing with the arrival of rains. It's necessary to know the N management to reduce the pollution risks and may lead the higher production with the fewer economic cost, environmental and health. The aim of this study was to asses how different doses of nitrogen applied to a melon crop affected the quality of groundwater. The doses of N applied ranged between 11 and 393 kg ha-1. Several indexes, based in N leaching consequence of the agricultural practice, were calculated and provided an essential tool for knowing the risks of groundwater pollution with the practices used. Drinking water impact, irrigation water management impact and environmental impact indexes were obtained during four years in a vulnerable area of the centre of Spain. Acknowledgements: This project has been supported by INIA-RTA04-111

  17. Comparative analysis of two different models of swimming applied to pregnant rats born small for pregnant age

    Directory of Open Access Journals (Sweden)

    SILVANA B. CORVINO

    Full Text Available ABSTRACT The aim of this study was to compare two models of swimming applied to pregnant rats born small for pregnancy age (SPA. Diabetes was chemically induced in adult female rats to develop an inadequate intrauterine environment, leading to birth of a SPA offspring. In adulthood, the female SPA rats were mated and submitted to different swimming programs. The exercise program 1 (Ex1 consisted of swimming for 15 minutes, followed by 15 minutes of rest and another 15 minutes of swimming, 3 days a week before and during pregnancy. Another program (Ex2 was applied during 60 minutes uninterrupted a day, 6 days/week during pregnancy. The pregnant rats presented no interference on body weight and glycemia. The rats submitted to Ex2 model showed decreased insulin and blood glucose levels by oral glucose tolerance test, and reduction in area under curve values. The offspring from dams submitted to both exercise protocols presented an increased rate of newborns SPA. However, the offspring from Ex2 dams showed percentage twice higher of newborns SPA than Ex1 offspring. Our data suggests that continuous exercise of 60 min/day ameliorated the enhanced peripheral insulin sensitivity in growth-restricted females. However, this protocol employed at pregnancy leads to intrauterine growth restriction.

  18. Comparative analysis of two different models of swimming applied to pregnant rats born small for pregnant age.

    Science.gov (United States)

    Corvino, Silvana B; Damasceno, Débora C; Sinzato, Yuri K; Netto, Aline O; Macedo, Nathália C D; Zambrano, Elena; Volpato, Gustavo T

    2017-01-01

    The aim of this study was to compare two models of swimming applied to pregnant rats born small for pregnancy age (SPA). Diabetes was chemically induced in adult female rats to develop an inadequate intrauterine environment, leading to birth of a SPA offspring. In adulthood, the female SPA rats were mated and submitted to different swimming programs. The exercise program 1 (Ex1) consisted of swimming for 15 minutes, followed by 15 minutes of rest and another 15 minutes of swimming, 3 days a week before and during pregnancy. Another program (Ex2) was applied during 60 minutes uninterrupted a day, 6 days/week during pregnancy. The pregnant rats presented no interference on body weight and glycemia. The rats submitted to Ex2 model showed decreased insulin and blood glucose levels by oral glucose tolerance test, and reduction in area under curve values. The offspring from dams submitted to both exercise protocols presented an increased rate of newborns SPA. However, the offspring from Ex2 dams showed percentage twice higher of newborns SPA than Ex1 offspring. Our data suggests that continuous exercise of 60 min/day ameliorated the enhanced peripheral insulin sensitivity in growth-restricted females. However, this protocol employed at pregnancy leads to intrauterine growth restriction.

  19. Preparation methodology and possible treatments for improved ceramics for high voltage vacuum applications

    CERN Document Server

    Tan, J

    1998-01-01

    The flashover characteristics of an insulator bridged high voltage vacuum gap can play an important role in the overall performance of a high voltage device, for example in the extreme environments of high energy particle accelerators. The detailed preparation of the insulators is, at present, governed by the commercial production methods and by standard bulk cleaning processes, which for a particular application may be far from optimum. The influence of the mechanical preparation, thermal history and particular cleaning technique have been investigated for commercially available alumina samples, with measurement of surface characteristics by scanning electron microscopy and laser diffraction, measurement of the secondary electron emission curve and analysis of the high voltage performance with the possibility of applied fields up to 200kV/cm. The results of the different measurements are discussed in the overall context of the problems encountered in the full sized high voltage devices, and suggestions are m...

  20. Application of Cat Swarm Optimization in testing Static Load Models for Voltage Stability

    Directory of Open Access Journals (Sweden)

    G. Naveen Kumar

    2016-03-01

    Full Text Available Power System Load Modeling is a method which is used to model the power system and essential for voltage stability studies. Voltage stability defines the ability of a power network to maintain steady state voltages at all the buses under normal operating conditions, and when subjected to a disturbance. The research presented as part of this paper, deals with analysis of different static load models for voltage stability studies. The precision of the results are directly related to the load models used in this analysis. The method is analyzed using continuation power flow routine. Flexible AC Transmission System technology with a combination of Cat Swarm Optimization Meta Heuristic Search approach is applied to give a solution for the problem of instability. The effectiveness of the proposed method is demonstrated through quantitative simulation on standard IEEE 14 bus system for contingency condition.

  1. Biological and Agricultural Studies on Application of Discharge Plasma and Electromagnetic Fields 4. Destruction of Weeds by High Voltage Discharge

    Science.gov (United States)

    Mizuno, Akira

    In an attempt to replace chemicals for weed control, high voltage spark discharge has been applied. With the application of high voltage, discharge takes place, and current flows through the stem and root. Microscopic observation indicates that cells are damaged. The electrical resistance of the damage plant’s stems and roots decreased significantly. Several different types of apparatus were constructed, and field test results show the effectiveness of electrical discharge for weed control.

  2. Tribological Investigations of Hard-Faced Layers and Base Materials of Forging Dies with Different Kinds of Lubricants Applied

    Directory of Open Access Journals (Sweden)

    V. Lazić

    2010-12-01

    Full Text Available This paper gives a procedure for choosing the right technology for reparative hard facing of damaged forging dies. Since they are subject to impact loads and cyclic temperature elevations, forging dies should be made of steel that is able to withstand great impact loads, maintain good mechanical properties at elevated temperatures and that is resistant to wear and thermal fatigue. For these reasons, forging dies are made of conditionally weldable alloy tool steels; however it makes hard facing of damaged tools even more difficult. In this paper, wear resistance of base materials, hard-faced layers and heat-affected zones are tribologically investigated when two different lubricants - pure synthetical oil LM 76 and LM 76 with 6% molybdenum disulfide (MoS2 are applied. Tribological investigations have shown that the wear resistance of the hard faced layers is considerably greater than the wear resistance of the base material. However, the base material has better properties concerning friction.

  3. New energy management circuit applied in electric self-power supply over high voltage side%新型高压侧自供电电源设计与研究

    Institute of Scientific and Technical Information of China (English)

    李衍川; 江和

    2014-01-01

    分析了高压电场能量收集的原理,建立静电场耦合分布电容模型,并通过实验证明了模型的参考价值。随后,分析使用整流桥电路进行能量管理时的最佳功率点,并从增大超级电容充电电流的角度,设计了一种新型的管理电路,即同步电荷提取电路,以获得最佳的能量存储能力。结果证明存在一个最佳占空比使得收集的能量最大化,从而缩短无线节点在线监测工作周期。%The theory of energy harvested from the high voltage is analyzed, and then the corresponding model of coupling capacitance derived from static electric field is built, and several experiments are conducted to study whether the model is valuable. Then, according to what the result reveals, the optimal power point is found out when energy is managed by rectifier circuit. The value of charged current to super capacitor is used as the judge-ment whether the circuit system has the best storage performance. In that respect, management circuit is improved as a technology called Synchronous Electric Charge Extract, because the rectifier circuit can’ t perform as good as it is under ultrahigh voltage. It turns out that there is an optimal duty to maximize the energy harvested, so that the energy harvester can scavenge much more energy to cancellout the power loss. As a result, online monitoring period could be shortened greatly.

  4. Effect of applied bias voltage on corrosion-resistance for TiC{sub 1-x}N{sub x} and Ti{sub 1-x}Nb{sub x}C{sub 1-y}N{sub y} coatings

    Energy Technology Data Exchange (ETDEWEB)

    Caicedo, J.C., E-mail: Jcesarca@calima.univalle.edu.co [Department of Physics, Universidad del Valle, Ciudad Universitaria Melendez, A.A. 25360 Cali (Colombia); Department de Fisica Aplicada i Optica, Universitat de Barcelona, Catalunya (Spain); Amaya, C. [Department of Physics, Universidad del Valle, Ciudad Universitaria Melendez, A.A. 25360 Cali (Colombia); Laboratorio de Recubrimientos Duros DT-ASTIN SENA, Cali (Colombia); Yate, L. [Department de Fisica Aplicada i Optica, Universitat de Barcelona, Catalunya (Spain); Aperador, W.; Zambrano, G.; Gomez, M.E. [Department of Physics, Universidad del Valle, Ciudad Universitaria Melendez, A.A. 25360 Cali (Colombia); Alvarado-Rivera, J.; Munoz-Saldana, J. [Centro de Investigacion y de Estudios Avanzados del IPN, Unidad Queretaro (Mexico); Prieto, P. [Department of Physics, Universidad del Valle, Ciudad Universitaria Melendez, A.A. 25360 Cali (Colombia); Centro de Excelencia en Nuevos Materiales, Calle 13 100-00 Edificio 320, espacio 1026, Cali (Colombia)

    2010-02-15

    Corrosion-resistance behavior of titanium carbon nitride (Ti-C-N) and titanium niobium carbon nitride (Ti-Nb-C-N) coatings deposited onto Si(1 0 0) and AISI 4140 steel substrates via r.f. magnetron sputtering process was analyzed. The coatings in contact with a solution of sodium chloride at 3.5% were studied by Tafel polarization curves and impedance spectroscopy methods (EIS). Variations of the bias voltage were carried out for each series of deposition to observe the influence of this parameter upon the electrochemical properties of the coatings. The introduction of Nb in the ternary Ti-C-N film was evaluated via X-ray diffraction (XRD) analysis. The structure was characterized by using Raman spectroscopy to identify ternary and quaternary compounds. Surface corrosion processes were characterized using optical microscopy and scanning electron microscopy (SEM). XRD results show conformation of the quaternary phase, change in the strain of the film, and lattice parameter as the effect of the Nb inclusion. The main Raman bands were assigned to interstitial phases and 'impurities' of the coatings. Changes in Raman intensities were attributed to the incorporation of niobium in the Ti-C-N structure and possibly to resonance enhancement. Finally, the corrosion data obtained for Ti-C-N were compared with the results of corrosion tests of Ti-Nb-C-N coating. The results obtained showed that the incorporation of niobium to Ti-C-N coatings led to an increase in the corrosion-resistance. On another hand, an increase in the bias voltage led to a decrease in the corrosion-resistance for both Ti-C-N and Ti-Nb-C-N coatings.

  5. A recombinant fusion protein containing a spider toxin specific for the insect voltage-gated sodium ion channel shows oral toxicity towards insects of different orders.

    Science.gov (United States)

    Yang, Sheng; Pyati, Prashant; Fitches, Elaine; Gatehouse, John A

    2014-04-01

    Recombinant fusion protein technology allows specific insecticidal protein and peptide toxins to display activity in orally-delivered biopesticides. The spider venom peptide δ-amaurobitoxin-PI1a, which targets insect voltage-gated sodium channels, was fused to the "carrier" snowdrop lectin (GNA) to confer oral toxicity. The toxin itself (PI1a) and an amaurobitoxin/GNA fusion protein (PI1a/GNA) were produced using the yeast Pichia pastoris as expression host. Although both proteins caused mortality when injected into cabbage moth (Mamestra brassicae) larvae, the PI1a/GNA fusion was approximately 6 times as effective as recombinant PI1a on a molar basis. PI1a alone was not orally active against cabbage moth larvae, but a single 30 μg dose of the PI1a/GNA fusion protein caused 100% larval mortality within 6 days when fed to 3rd instar larvae, and caused significant reductions in survival, growth and feeding in 4th - 6th instar larvae. Transport of fusion protein from gut contents to the haemolymph of cabbage moth larvae, and binding to the nerve chord, was shown by Western blotting. The PI1a/GNA fusion protein also caused mortality when delivered orally to dipteran (Musca domestica; housefly) and hemipteran (Acyrthosiphon pisum; pea aphid) insects, making it a promising candidate for development as a biopesticide.

  6. Imaging with low-voltage scanning transmission electron microscopy: A quantitative analysis

    Energy Technology Data Exchange (ETDEWEB)

    Felisari, L. [TASC, INFM-CNR, S.S. 14, km 163.5, 34149 Trieste (Italy); Grillo, V., E-mail: vincenzo.grillo@unimore.it [Istituto Nanoscienze-S3 CNR, via Campi 213/A, 41125 Modena (Italy); IMEM-CNR Parco Area delle Scienze 37/A, 43124 Parma (Italy); Jabeen, F.; Rubini, S. [TASC, INFM-CNR, S.S. 14, km 163.5, 34149 Trieste (Italy); Menozzi, C. [Istituto Nanoscienze-S3 CNR, via Campi 213/A, 41125 Modena (Italy); Dipartimento di Fisica, Universita di Modena e Reggio Emilia Via G. Campi 213/A, 41100 Modena (Italy); Rossi, F. [IMEM-CNR Parco Area delle Scienze 37/A, 43124 Parma (Italy); Martelli, F. [TASC, INFM-CNR, S.S. 14, km 163.5, 34149 Trieste (Italy); IMM-CNR, via del Fosso del Cavaliere 100, 00133 Roma (Italy)

    2011-07-15

    A dedicated specimen holder has been designed to perform low-voltage scanning transmission electron microscopy in dark field mode. Different test samples, namely InGaAs/GaAs quantum wells, InGaAs nanowires and thick InGaAs layers, have been analysed to test the reliability of the model based on the proportionality to the specimen mass-thickness, generally used for image intensity interpretation of scattering contrast processes. We found that size of the probe, absorption and channelling must be taken into account to give a quantitative interpretation of image intensity. We develop a simple procedure to evaluate the probe-size effect and to obtain a quantitative indication of the absorption coefficient. Possible artefacts induced by channelling are pointed out. With the developed procedure, the low voltage approach can be successfully applied for quantitative compositional analysis. The method is then applied to the estimation of the In content in the core of InGaAs/GaAs core-shell nanowires. -- Highlights: {yields} Quantitative analysis of the composition by low-voltage STEM annular dark field. {yields} First evidence of channelling effects in low-voltage STEM in SEM. {yields} Comparison between low-voltage and high-voltage STEM. {yields} Evaluation of the absorption effects on the STEM intensity.

  7. Investigation of the built-in voltage in organic pin solar cells using electroabsorption spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Siebert-Henze, Ellen; Tress, Wolfgang; Lyssenko, Vadim G.; Hintschich, Susanne I.; Leo, Karl; Riede, Moritz [Institut fuer Angewandte Photophysik, Dresden (Germany)

    2011-07-01

    The built-in voltage of small molecule organic solar cells based on the pin concept is investigated. We use the method of electroabsorption spectroscopy whose principle is the detection of absorption changes due to electrical excitation (Stark effect). A voltage consisting of a DC and an AC part is applied to the sample and the change in absorption is detected using a lock-in amplifier. The variation of the applied DC voltage modifies the DC field across the sample leading to a linear change of the corresponding Stark signal. This supplies information about the built-in voltage of the device which is determined for different combinations of donor materials and hole transport materials (MeO-TPD, BPAPF, alpha-NPD, and ZnPc). In addition, the doping concentration of the hole transport layer is modified and the influence of the consequential change of the work function on the built-in voltage is examined. It is shown that both the short-circuit current as well as the fill factor increase for larger built-in voltages.

  8. High Voltage Distribution

    Science.gov (United States)

    Norbeck, Edwin; Miller, Michael; Onel, Yasar

    2010-11-01

    For detector arrays that require 5 to 10 kV at a few microamps each for hundreds of detectors, using hundreds of HV power supplies is unreasonable. Bundles of hundreds of HV cables take up space that should be filled with detectors. A typical HV module can supply 1 ma, enough current for hundreds of detectors. It is better to use a single HV module and distribute the current as needed. We show a circuit that, for each detector, measures the current, cuts off the voltage if the current exceeds a set maximum, and allows the HV to be turned on or off from a control computer. The entire array requires a single HV cable and 2 or 3 control lines. This design provides the same voltage to all of the detectors, the voltage set by the single HV module. Some additional circuitry would allow a computer controlled voltage drop between the HV and each individual detector.

  9. High voltage engineering fundamentals

    CERN Document Server

    Kuffel, E; Hammond, P

    1984-01-01

    Provides a comprehensive treatment of high voltage engineering fundamentals at the introductory and intermediate levels. It covers: techniques used for generation and measurement of high direct, alternating and surge voltages for general application in industrial testing and selected special examples found in basic research; analytical and numerical calculation of electrostatic fields in simple practical insulation system; basic ionisation and decay processes in gases and breakdown mechanisms of gaseous, liquid and solid dielectrics; partial discharges and modern discharge detectors; and over

  10. A comparative study for different shielding material composition and beam geometry applied to PET facilities: simulated transmission curves

    Energy Technology Data Exchange (ETDEWEB)

    Hoff, Gabriela [Pontificia Univ. Catolica do Rio Grande do Sul (PUCRS), Porto Alegre, RS (Brazil). Grupo de Experimentacao e Simulacao Computacional em Fisica Medica; Costa, Paulo Roberto, E-mail: pcosta@if.usp.br [Universidade de Sao Paulo (IF/USP), SP (Brazil). Dept. de Fisica Nuclear. Lab. de Dosimetria das Radiacoes e Fisica Medica

    2013-03-15

    The aim of this work is to simulate transmission data for different beam geometry and material composition in order to evaluate the effect of these parameters on transmission curves. The simulations are focused on outgoing spectra for shielding barriers used in PET facilities. The behavior of the transmission was evaluated as a function of the shielding material composition and thickness using Geant4 Monte Carlo code, version 9.2 p 03.The application was benchmarked for barited mortar and compared to The American Association of Physicists in Medicine (AAPM) data for lead. Their influence on the transmission curves as well the study of the influence of the shielding material composition and beam geometry on the outgoing spectra were performed. Characteristics of transmitted spectra, such as shape, average energy and Half-Value Layer (HVL), were also evaluated. The Geant4 toolkit benchmark for the energy resulting from the positron annihilation phenomena and its application in transmission curves description shown good agreement between data published by American Association on Physicists in Medicine task group 108 and experimental data published by Brazil. The transmission properties for different material compositions were also studied and have shown low dependency with the considered thicknesses. The broad and narrow beams configuration presented significant differences on the result. The fitting parameter for determining the transmission curves equations, according to Archer model is presented for different material. As conclusion were defined that beam geometry has significant influence and the composition has low influence on transmission curves for shielding design for the range of energy applied to PET. (author)

  11. Practical considerations in voltage stability assessment

    Energy Technology Data Exchange (ETDEWEB)

    Kundur, P.; Gao, B. [Powertech Labs. Inc., Surrey, BC (Canada)

    1994-12-31

    This paper deals with some of the most important practical issues related to voltage stability assessment of large practical systems. A brief discussion of the practical aspects of voltage stability problem and prevention of voltage instability is given first, followed by descriptions of different analytical techniques and tools for voltage stability analysis. Presentations of analytical tools is focused on the VSTAB program which incorporates the modal analysis, continuation power flow, and shortest distance to instability techniques, Finally, an example case study of a practical large system is presented. The case study illustrates how modal analysis is used to determine the most effective load shedding scheme for preventing voltage instability. (author) 15 refs., 2 figs., 2 tabs.

  12. Current–voltage characteristics of manganite–titanite perovskite junctions

    Directory of Open Access Journals (Sweden)

    Benedikt Ifland

    2015-07-01

    Full Text Available After a general introduction into the Shockley theory of current voltage (J–V characteristics of inorganic and organic semiconductor junctions of different bandwidth, we apply the Shockley theory-based, one diode model to a new type of perovskite junctions with polaronic charge carriers. In particular, we studied manganite–titanate p–n heterojunctions made of n-doped SrTi1−yNbyO3, y = 0.002 and p-doped Pr1−xCaxMnO3, x = 0.34 having a strongly correlated electron system. The diffusion length of the polaron carriers was analyzed by electron beam-induced current (EBIC in a thin cross plane lamella of the junction. In the J–V characteristics, the polaronic nature of the charge carriers is exhibited mainly by the temperature dependence of the microscopic parameters, such as the hopping mobility of the series resistance and a colossal electro-resistance (CER effect in the parallel resistance. We conclude that a modification of the Shockley equation incorporating voltage-dependent microscopic polaron parameters is required. Specifically, the voltage dependence of the reverse saturation current density is analyzed and interpreted as a voltage-dependent electron–polaron hole–polaron pair generation and separation at the interface.

  13. Low-voltage gyrotrons

    Science.gov (United States)

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

    2013-03-01

    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).

  14. Geographical variations in the benefit of applying a prioritization system for cataract surgery in different regions of Spain

    Directory of Open Access Journals (Sweden)

    Gutiérrez-Moreno Santiago

    2008-02-01

    Full Text Available Abstract Background In Spain, there are substantial variations in the utilization of health resources among regions. Because the need for surgery differs in patients with appropriate surgical indication, introducing a prioritization system might be beneficial. Our objective was to assess geographical variations in the impact of applying a prioritization system in patients on the waiting list for cataract surgery in different regions of Spain by using a discrete-event simulation model. Methods A discrete-event simulation model to evaluate demand and waiting time for cataract surgery was constructed. The model was reproduced and validated in five regions of Spain and was fed administrative data (population census, surgery rates, waiting list information and data from research studies (incidence of cataract. The benefit of introducing a prioritization system was contrasted with the usual first-in, first-out (FIFO discipline. The prioritization system included clinical, functional and social criteria. Priority scores ranged between 0 and 100, with greater values indicating higher priority. The measure of results was the waiting time weighted by the priority score of each patient who had passed through the waiting list. Benefit was calculated as the difference in time weighted by priority score between operating according to waiting time or to priority. Results The mean waiting time for patients undergoing surgery according to the FIFO discipline varied from 1.97 months (95% CI 1.85; 2.09 in the Basque Country to 10.02 months (95% CI 9.91; 10.12 in the Canary Islands. When the prioritization system was applied, the mean waiting time was reduced to a minimum of 0.73 months weighted by priority score (95% CI 0.68; 0.78 in the Basque Country and a maximum of 5.63 months (95% CI 5.57; 5.69 in the Canary Islands. The waiting time weighted by priority score saved by the prioritization system varied from 1.12 months (95% CI 1.07; 1.16 in Andalusia to 2

  15. The effect of silane applied to glass ceramics on surface structure and bonding strength at different temperatures

    Science.gov (United States)

    Eraslan, Oguz

    2016-01-01

    PURPOSE To evaluate the effect of various surface treatments on the surface structure and shear bond strength (SBS) of different ceramics. MATERIALS AND METHODS 288 specimens (lithium-disilicate, leucite-reinforced, and glass infiltrated zirconia) were first divided into two groups according to the resin cement used, and were later divided into four groups according to the given surface treatments: G1 (hydrofluoric acid (HF)+silane), G2 (silane alone-no heat-treatment), G3 (silane alone-then dried with 60℃ heat-treatment), and G4 (silane alone-then dried with 100℃ heat-treatment). Two different adhesive luting systems were applied onto the ceramic discs in all groups. SBS (in MPa) was calculated from the failure load per bonded area (in N/mm2). Subsequently, one specimen from each group was prepared for SEM evaluation of the separated-resin–ceramic interface. RESULTS SBS values of G1 were significantly higher than those of the other groups in the lithium disilicate ceramic and leucite reinforced ceramic, and the SBS values of G4 and G1 were significantly higher than those of G2 and G3 in glass infiltrated zirconia. The three-way ANOVA revealed that the SBS values were significantly affected by the type of resin cement (Pacid etching. The surface topography of ceramics was affected by surface treatments. PMID:27141250

  16. Experimental investigation of different active noise control concepts applied to a passenger car equipped with an active windshield

    Science.gov (United States)

    Misol, M.; Algermissen, S.; Monner, H. P.

    2012-05-01

    The main purpose of this work is the implementation and experimental investigation of different active structural acoustic control (ASAC) concepts for the reduction of interior noise in an automobile passenger compartment. For the control experiments, a medium-class test car was used, which had been equipped with an active windshield. The active windshield consists of the serial-production laminated glass pane augmented with piezoceramic patch-transducers applied to the blackened rim of the windshield. A multi-reference test provided measurement data for the identification of a local discrete-time state-space model (SSM). The subsequent acquisition of frequency response functions (FRF) by way of using the same actuators but measuring on a much finer grid provided the database for the formulation of a least-squares problem to derive a global system model. Based on the local and global discrete-time SSMs, different controllers were designed and experimentally realized. The comparison of the vibration levels in open- and closed-loop showed a global reduction of 5-7 dB in the acoustically relevant frequency band containing the second and third structural resonance of the windshield system. The occurrence of complex operational deflection shapes (ODS) was identified as the main limitation concerning the disturbance rejection of the active system. The acoustic performance of the ASAC system is reflected in a reduction up to 15 dB in sound pressure level (SPL).

  17. Artifical Excitation of Ferro-Resonance for Testing Electrotechnical Equipment in Distribution Devices with Increased Voltage

    Directory of Open Access Journals (Sweden)

    Ye. V. Dmitriev

    2006-01-01

    Full Text Available On the basis of the developed device for protection against of ferro-resonant and high-frequency cumulative over-voltages an algorithm for obtaining a voltage imitating ferro-resonant over-voltages is proposed in the paper. This algorithm presupposes to apply a voltage to the secondary transformer side from an extraneous source is proposed.

  18. Secondary control for voltage unbalance compensation in an islanded microgrid

    DEFF Research Database (Denmark)

    Savaghebi, Mehdi; Guerrero, Josep M.; Jalilian, Alireza

    2011-01-01

    In this paper, the concept of secondary control is applied for voltage unbalance compensation in an islanded microgrid. The aim of the proposed control approach is to enhance the voltage quality at the point of common coupling (PCC). Unbalance compensation is achieved by proper control of distrib......In this paper, the concept of secondary control is applied for voltage unbalance compensation in an islanded microgrid. The aim of the proposed control approach is to enhance the voltage quality at the point of common coupling (PCC). Unbalance compensation is achieved by proper control...

  19. Comparison of two different sea-salt aerosol schemes as implemented in air quality models applied to the Mediterranean Basin

    Directory of Open Access Journals (Sweden)

    P. Jiménez-Guerrero

    2011-05-01

    Full Text Available A number of attempts have been made to incorporate sea-salt aerosol (SSA source functions in chemistry transport models with varying results according to the complexity of the scheme considered. This contribution compares the inclusion of two different SSA algorithms in two chemistry transport models: CMAQ and CHIMERE. The main goal is to examine the differences in average SSA mass and composition and to study the seasonality of the prediction of SSA when applied to the Mediterranean area with high resolution for a reference year. Dry and wet deposition schemes are also analyzed to better understand the differences observed between both models in the target area. The applied emission algorithm in CHIMERE uses a semi-empirical formulation which obtains the surface emission rate of SSA as a function of the particle size and the surface wind speed raised to the power 3.41. The emission parameterization included within CMAQ is somehow more sophisticated, since fluxes of SSA are corrected with relative humidity. In order to evaluate their strengths and weaknesses, the participating algorithms as implemented in the chemistry transport models were evaluated against AOD measurements from Aeronet and available surface measurements in Southern Europe and the Mediterranean area, showing biases around −0.002 and −1.2 μg m−3, respectively. The results indicate that both models represent accurately the patterns and dynamics of SSA and its non-uniform behavior in the Mediterranean basin, showing a strong seasonality. The levels of SSA strongly vary across the Western and the Eastern Mediterranean, reproducing CHIMERE higher annual levels in the Aegean Sea (12 μg m−3 and CMAQ in the Gulf of Lion (9 μg m−3. The large difference found for the ratio PM2.5/total SSA in CMAQ and CHIMERE is also investigated. The dry and wet removal rates are very similar for both models despite the different schemes

  20. A SURVEY: PID OPTIMIZATION FOR AUTOMATIC VOLTAGE REGULATOR

    OpenAIRE

    Ajay Dixit*, Miss.Pragati Joshi, Mr.Mahesh Lokhande

    2016-01-01

    This paper presents on survey paper  of PSO and automatic voltage regulator for synchronous generator. It is used to obtain for regulation and stability of any electrical equipment. There are many technology/methods were used in automatic voltage regulator as well as different controller used for improving robustness, overshoot, rise time and voltage control but problem is about to survey on Automatic Voltage Regulator. Comparisons studies which are based on PID Controller are performed to sh...

  1. Evaluation on the tribological properties of palm olein in different loads applied using pin-on-disk tribotester

    Directory of Open Access Journals (Sweden)

    N. Sapawe

    2014-12-01

    Full Text Available The vegetable oil based lubricant as lubricant in various applications were intensified and eyed by the industry due to its superior tribological properties, and has potential to replace petroleum based lubricants. Palm olein could be suitable and attractive candidate as the lubricant to be studied due to its good advantages and large production in country. Thus, in the study the behavior of RBD palm olein characteristic was investigated by pin on disk experiment in which the hemispherical pin was loaded against the rotating grooved disk. The experiments by sliding were performed in pin on disk tester using titanium as material for both hemispherical pin and grooved disk. The test were implemented by dropping 5 ml of RBD palm olein as lubricating oil on sliding surface at different loads applied which were 5N, 20N, 40N and 80N. The wear rate of the pin and friction coefficient was also investigated. The weight loss and surface roughness before and after experiment were analyzed. All the results obtained were compared to hydraulic oil and paraffinic mineral oil. From the analysis, friction coefficient acquired lubricated with RBD palm olein was the lowest for both conditions. Wear rate obtained for three lubricants increased from 5N to 20N load, then decreased after 40N load and increased again after 80N load exerted. Wear obtained lubricated with hydraulic oil shows the lowest value compared to paraffinic mineral oil and RBD palm olein.

  2. Comparison of the density-matrix renormalization group method applied to fractional quantum Hall systems in different geometries

    Energy Technology Data Exchange (ETDEWEB)

    Hu, Zi-Xiang, E-mail: zihu@princeton.edu [Department of Electrical Engineering, Princeton University, Princeton, NJ 08544 (United States); Department of Physics, ChongQing University, ChongQing 400044 (China); Papić, Z.; Johri, S.; Bhatt, R.N. [Department of Electrical Engineering, Princeton University, Princeton, NJ 08544 (United States); Schmitteckert, Peter [Institut für Nanotechnologie, Forschungszentrum Karlsruhe, D-76021 Karlsruhe (Germany)

    2012-06-18

    We report a systematic study of the fractional quantum Hall effect (FQHE) using the density-matrix renormalization group (DMRG) method on two different geometries: the sphere and the cylinder. We provide convergence benchmarks based on model Hamiltonians known to possess exact zero-energy ground states, as well as an analysis of the number of sweeps and basis elements that need to be kept in order to achieve the desired accuracy. The ground state energies of the Coulomb Hamiltonian at ν=1/3 and ν=5/2 filling are extracted and compared with the results obtained by previous DMRG implementations in the literature. A remarkably rapid convergence in the cylinder geometry is noted and suggests that this boundary condition is particularly suited for the application of the DMRG method to the FQHE. -- Highlights: ► FQHE is a two-dimensional physics. ► Density-matrix renormalization group method applied to FQH systems. ► Benchmark study both on sphere and cylinder geometry.

  3. Hysteresis in voltage-gated channels.

    Science.gov (United States)

    Villalba-Galea, Carlos A

    2016-09-30

    Ion channels constitute a superfamily of membrane proteins found in all living creatures. Their activity allows fast translocation of ions across the plasma membrane down the ion's transmembrane electrochemical gradient, resulting in a difference in electrical potential across the plasma membrane, known as the membrane potential. A group within this superfamily, namely voltage-gated channels, displays activity that is sensitive to the membrane potential. The activity of voltage-gated channels is controlled by the membrane potential, while the membrane potential is changed by these channels' activity. This interplay produces variations in the membrane potential that have evolved into electrical signals in many organisms. These signals are essential for numerous biological processes, including neuronal activity, insulin release, muscle contraction, fertilization and many others. In recent years, the activity of the voltage-gated channels has been observed not to follow a simple relationship with the membrane potential. Instead, it has been shown that the activity of voltage-gated channel displays hysteresis. In fact, a growing number of evidence have demonstrated that the voltage dependence of channel activity is dynamically modulated by activity itself. In spite of the great impact that this property can have on electrical signaling, hysteresis in voltage-gated channels is often overlooked. Addressing this issue, this review provides examples of voltage-gated ion channels displaying hysteretic behavior. Further, this review will discuss how Dynamic Voltage Dependence in voltage-gated channels can have a physiological role in electrical signaling. Furthermore, this review will elaborate on the current thoughts on the mechanism underlying hysteresis in voltage-gated channels.

  4. P Voltage Control of DFIG with Two-Mass-Shaft Turbine Model Under Utility Voltage Disturbance

    Directory of Open Access Journals (Sweden)

    Hengameh Kojooyan Jafari

    2016-06-01

    Full Text Available Doubly fed induction generators as a variable speed induction generators are applied instead of other electric machines in wind power plants to be connected to the grid with flexible controllers. Nowadays one of the most important subjects in wind farms is control of output power delivered to the grid under utility disturbance. In this paper, a doubly-fed induction generator with external rotor resistance and power converters model as an external voltage source having an adjustable phase and amplitude with an ordinary turbine connected to one mass shaft model and also two mass shaft model, is used and controlled by a P voltage controller to control the output active power for typical high and low wind speeds under two conditions of utility disturbance; while time of disturbance is not too long to change the domain of external rotor voltage source and also while time is long and the domain of external rotor voltage decreases.Simulation results show that P voltage controller can control output active power under 27% stator voltage drop down for typical low wind speed and 11% stator voltage drop down for typical high wind speed in long time disturbance while 80% of rotor external voltage domain drops down under short time utility disturbance.

  5. Enhanced thermal stability and mechanical properties of nitrogen deficient titanium aluminum nitride (Ti0.54Al0.46Ny) thin films by tuning the applied negative bias voltage

    Science.gov (United States)

    Calamba, K. M.; Schramm, I. C.; Johansson Jõesaar, M. P.; Ghanbaja, J.; Pierson, J. F.; Mücklich, F.; Odén, M.

    2017-08-01

    Aspects on the phase stability and mechanical properties of nitrogen deficient (Ti0.54Al0.46)Ny alloys were investigated. Solid solution alloys of (Ti,Al)N were grown by cathodic arc deposition. The kinetic energy of the impinging ions was altered by varying the substrate bias voltage from -30 V to -80 V. Films deposited with a high bias value of -80 V showed larger lattice parameter, finer columnar structure, and higher compressive residual stress resulting in higher hardness than films biased at -30 V when comparing their as-deposited states. At elevated temperatures, the presence of nitrogen vacancies and point defects (anti-sites and self-interstitials generated by the ion-bombardment during coating deposition) in (Ti0.54Al0.46)N0.87 influence the driving force for phase separation. Highly biased nitrogen deficient films have point defects with higher stability during annealing, which cause a delay of the release of the stored lattice strain energy and then accelerates the decomposition tendencies to thermodynamically stable c-TiN and w-AlN. Low biased nitrogen deficient films have retarded phase transformation to w-AlN, which results in the prolongment of age hardening effect up to 1100 °C, i.e., the highest reported temperature for Ti-Al-N material system. Our study points out the role of vacancies and point defects in engineering thin films with enhanced thermal stability and mechanical properties for high temperature hard coating applications.

  6. Asymmetric voltage behavior of the tunnel magnetoresistance in double barrier magnetic tunnel junctions

    KAUST Repository

    Useinov, Arthur

    2012-06-01

    In this paper, we study the value of the tunnel magnetoresistance (TMR) as a function of the applied voltage in double barrier magnetic tunnel junctions (DMTJs) with the left and right ferromagnetic (FM) layers being pinned and numerically estimate the possible difference of the TMR curves for negative and positive voltages in the homojunctions (equal barriers and electrodes). DMTJs are modeled as two single barrier junctions connected in series with consecutive tunneling (CST). We investigated the asymmetric voltage behavior of the TMR for the CST in the range of a general theoretical model. Significant asymmetries of the experimental curves, which arise due to different annealing regimes, are mostly explained by different heights of the tunnel barriers and asymmetries of spin polarizations in magnetic layers. © (2012) Trans Tech Publications.

  7. Free-roaming dog populations: a cost-benefit model for different management options, applied to Abruzzo, Italy.

    Science.gov (United States)

    Høgåsen, H R; Er, C; Di Nardo, A; Dalla Villa, P

    2013-11-01

    Since 1991, Italian free-roaming dogs have been under government protection and euthanasia is restricted by law. Management measures are regulated at the regional level and include: kennelling, adoptions, conversion of stray dogs into block dogs, and population control of owned dogs. "Block dogs" are free-roaming dogs that have been collected by the veterinary services, microchipped, sterilised, vaccinated, and released under the responsibility of the local municipalities. The present paper describes a cost-benefit model for different management options and applies it to two provinces in Abruzzo, central Italy. The model considers welfare, nuisance and direct costs to the municipality. Welfare is quantified based on the expert opinions of 60 local veterinarians, who were asked to assign a score for each dog category according to the five freedoms: freedom from pain, physical discomfort, disease, fear, and freedom to express normal behaviour. Nuisance was assessed only for comparisons between management options, using the number of free-roaming dogs per inhabitant as a proxy indicator. A community dog population model was constructed to predict the effect of management on the different subpopulations of dogs during a ten-year period. It is a user-friendly deterministic model in Excel, easily adaptable to different communities to assess the impact of their dog management policy on welfare, nuisance and direct monetary cost. We present results for Teramo and Pescara provinces. Today's management system is compared to alternative models, which evaluate the effect of specific interventions. These include either a 10% yearly increase in kennel capacity, an increase in adoptions from kennels, a doubling of the capture of stray dogs, or a stabilisation of the owned dog population. Results indicate that optimal management decisions are complex because welfare, nuisance and monetary costs may imply conflicting interventions. Nevertheless, they clearly indicate that

  8. Voltage Regulators for Photovoltaic Systems

    Science.gov (United States)

    Delombard, R.

    1986-01-01

    Two simple circuits developed to provide voltage regulation for highvoltage (i.e., is greater than 75 volts) and low-voltage (i.e., is less than 36 volts) photovoltaic/battery power systems. Use of these circuits results in voltage regulator small, low-cost, and reliable, with very low power dissipation. Simple oscillator circuit controls photovoltaic-array current to regulate system voltage and control battery charging. Circuit senses battery (and system) voltage and adjusts array current to keep battery voltage from exceeding maximum voltage.

  9. Air Breakdown Behavior of Two Series Gaps for Composite Switching Impulse/Alternating Voltage

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    More and more high voltage transmission lines make use of rubber housed ZnO arresters in series with another air gap (for example, the insulator gap) as lighting protection elements. Many test results of ZnO arresters protection performance show that this insulation arrangement is suitable for practical lines according to results based on only simple impulse voltage. This paper uses a composite voltage (switching impulse voltage/alternating voltage) to determine the air breakdown behavior of the conductor-rod gap in series with the sphere gap. In the test, the switching impulse voltage is applied to the conductor while the alternating voltage is applied to the rod and one sphere and the other sphere is grounded. The results show that in some cases, the value of the U50% sparkover voltage for the conductor-rod gap with the composite voltage is nearly only half of that for just the simple impulse voltage.

  10. L{sub p} norm approaches for estimating voltage flicker

    Energy Technology Data Exchange (ETDEWEB)

    Inan, Aslan [Department of Electrical Engineering, Faculty of Electrical-Electronics, Yildiz Technical University, Istanbul (Turkey); Bakroun, Maher [Antrim Crescent, Toronto, Ontario (Canada); Heydt, Gerald T. [Fulton School of Engineering, Arizona State University, Tempe, AZ (United States)

    2010-12-15

    It is important to accurately estimate instantaneous voltage flicker magnitudes and frequencies in order to correctly evaluate voltage fluctuations. Voltage flicker is a problem in electric power quality. Different approaches used to determine the magnitude of the voltage flicker have been presented: measurement methods generally use a flickermeter device. Simulation methods require a computer model of the disturbing load and the flickermeter. Calculation methods necessitate a simplified empirical formula. Estimation algorithms are based on the estimation of the voltage flicker components. In this paper, two models of voltage flicker are discussed: L{sub p} estimation algorithms utilizing L{sub 1}, L{sub 2} and L{sub {infinity}} norms are used to estimate the voltage magnitudes of the flicker signals as well as the fundamental voltage magnitude. The main result is that it is possible to design an L{sub p} estimator to identify flicker frequency and amplitude from time series measurements. (author)

  11. Effect of applying bacterial inoculants containing different types of bacteria to corn silage on the performance of dairy cattle.

    Science.gov (United States)

    Arriola, K G; Kim, S C; Staples, C R; Adesogan, A T

    2011-08-01

    This study examined the effect of applying different bacterial inoculants to corn silage at the time of ensiling on the performance of lactating dairy cows. Corn plants were harvested at 35% dry matter (DM), chopped, and ensiled in 2.4-m-wide bags after application of (1) no inoculant (CON); (2) Biotal Plus II (B2) containing Pediococcus pentosaceus and Propionibacteria freudenreichii; (3) Buchneri 40788 (BUC) containing Lactobacillus buchneri; or (4) Buchneri 500 (B500) containing Pediococcus pentosaceus and L. buchneri. All inoculants were supplied by Lallemand Animal Nutrition (Milwaukee, WI). Each of the 4 silages was included in separate total mixed rations consisting of 44% corn silage, 50% concentrate, and 6% alfalfa hay (DM basis). Fifty-two lactating Holstein cows were stratified according to milk production and parity and randomly assigned at 22 d in milk to the 4 dietary treatments. Cows were fed for ad libitum consumption and milked twice daily for 49 d. Dietary treatment did not affect intakes (kg/d) of DM (20.0), crude protein (CP; 3.7), neutral detergent fiber (NDF; 5.7), or acid detergent fiber (ADF; 3.6), or digestibility (%) of DM (73.9) or CP (72.4). However, NDF digestibility was lower in cows fed B2 compared with those fed other diets (45.3 vs. 53.0%). Consequently, cows fed B2 had lower digestible NDF intake (kg/d) than those fed other diets (2.5 vs. 3.0 kg/d). Dietary treatment did not affect milk yield (32.3 kg/d), efficiency of milk production (1.61), concentrations of milk fat (3.18%) and protein (2.79%), or yields of milk fat (1.03 kg/d) and protein (1.26 kg/d). Inoculant application to corn silage did not affect milk yield or feed intake of cows.

  12. Effects of Absolute Humidity on Flashover Voltage of Insulators

    Science.gov (United States)

    Fujii, Osamu; Hidaka, Kazuhiro; Mizuno, Yukio; Naito, Katsuhiko; Irie, Takashi; Nishikawa, Morio

    Effect of humidity on flashover voltage of three kinds of insulators is experimentally studied for about three years under natural humidity condition. It is found that the existing IEC humidity correction seems to be proper for most insulators regardless of the kinds of applied voltage but that change may be necessary for a cap and pin insulator unit under the application of positive and negative lightning impulse voltages.

  13. Voltage regulation of connexin channel conductance.

    Science.gov (United States)

    Oh, Seunghoon; Bargiello, Thaddeus A

    2015-01-01

    Voltage is an important parameter that regulates the conductance of both intercellular and plasma membrane channels (undocked hemichannels) formed by the 21 members of the mammalian connexin gene family. Connexin channels display two forms of voltage-dependence, rectification of ionic currents and voltage-dependent gating. Ionic rectification results either from asymmetries in the distribution of fixed charges due to heterotypic pairing of different hemichannels, or by channel block, arising from differences in the concentrations of divalent cations on opposite sides of the junctional plaque. This rectification likely underpins the electrical rectification observed in some electrical synapses. Both intercellular and undocked hemichannels also display two distinct forms of voltage-dependent gating, termed Vj (fast)-gating and loop (slow)-gating. This review summarizes our current understanding of the molecular determinants and mechanisms underlying these conformational changes derived from experimental, molecular-genetic, structural, and computational approaches.

  14. Low Voltage Analog Circuit Design Based on the Flipped Voltage Follower

    Directory of Open Access Journals (Sweden)

    Neeraj Yadav

    2012-03-01

    Full Text Available The desire for portability of electronics equipment generated a need for low power system in battery products like hearing aids, implantable cardiac pacemakers, cell phones and hand held multimedia terminals. Low voltage analog circuit design differs considerably from those of high voltage analog circuit design. This paper present the basic cell knows as “flipped voltage follower” for low voltage/ low power operation. The detailed classification of basic topologies derived from the FVF cell is presented and there is a low voltage current mirror based on FVF cell has been presented. All the Circuit has been simulated using Hspice tool 0.18µm CMOS Technology. Different quality factors such as frequency response, power consumption are considered. A compression also made between previous current mirror and new designed current mirror. The layout of the current mirror has been also designed using Cadence tool.

  15. Deicing of medium voltage power transmission lines by Joule heating method

    Energy Technology Data Exchange (ETDEWEB)

    Farokhi, S.; Vahidi, B. [Amirkabir Univ. of Technology, Tehran (Iran, Islamic Republic of). Electrical Engineering Dept.

    2005-07-01

    A Joule heating method for the de-icing of overhead transmission lines was presented. The combined use of short circuits and reduced voltage was introduced as as effective method for the de-icing of sub-transmission lines of a utility in Iran. The method is able to melt ice in a short period of time. The required electrical current and the time needed for melting the ice as a function of wind speed, air temperature and ice thickness was determined by using a finite difference heat transfer model which considered the heat flux terms. An algorithm of the application method was proposed using the finite difference heat transfer model and considering steady state radial heat conduction. The required time for melting the accumulated ice on overhead transmission lines for different values of line current and climatic conditions was calculated. In the proposed method, after disconnecting the end of the line, a 3 phase short circuit was applied and accumulated ice was melted because of Joule losses. The main restrictions to the method were the current rating of facilities, and source capacity. After a consideration of these restrictions, instead of feeding the line by rated voltage, a voltage with a value of about 20 to 40 per cent of its rated voltage was applied and a short circuit on the end of the line should be made. The algorithm was made by collecting the data for the power system, disconnecting both ends of the line from the system and applying required changes on loads. transformers calculated from the load flow of the system. The line was fed with the reduced voltage by connecting the line to a lower level voltage. A case study of the method was presented. 10 refs., 1 tab., 4 figs.

  16. VOLTAGE REGULATORS ASYNCHRONOUS GENERATORS

    Directory of Open Access Journals (Sweden)

    Grigorash O. V.

    2015-06-01

    Full Text Available A promising is currently the use of asynchronous generators with capacitive excitation as a source of electricity in stand-alone power systems. Drive asynchronous generators may exercise as a thermal engine and wind wheel wind power plant or turbines of small hydropower plants. The article discusses the structural and schematics of voltage stabilizers and frequency of asynchronous generators with improved operational and technical specifications. Technical novelty of design solutions of the magnetic system and stabilizers asynchronous generator of electricity parameters confirmed by the patents for the invention of the Russian Federation. The proposed technical solution voltage stabilizer asynchronous generators, can reduce the weight of the block capacitors excitation and reactive power compensation, as well as to simplify the control system power circuit which has less power electronic devices. For wind power plants it is an important issue not only to stabilize the voltage of the generator, but also the frequency of the current. Recommend functionality stabilizer schemes parameters of electric power made for direct frequency converters with artificial and natural switching power electronic devices. It is also proposed as part of stabilization systems use single-phase voltage, three-phase transformers with rotating magnetic field, reduce the level of electromagnetic interference generated by power electronic devices for switching, enhance the efficiency and reliability of the stabilizer.

  17. Geomagnetism and Induced Voltage

    Science.gov (United States)

    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…

  18. High-voltage picoamperemeter

    Energy Technology Data Exchange (ETDEWEB)

    Bugl, Andrea; Ball, Markus; Boehmer, Michael; Doerheim, Sverre; Hoenle, Andreas; Konorov, Igor [Technische Universitaet Muenchen, Garching (Germany); Ketzer, Bernhard [Technische Universitaet Muenchen, Garching (Germany); Helmholtz-Institut fuer Strahlen- und Kernphysik, Bonn (Germany)

    2014-07-01

    Current measurements in the nano- and picoampere region on high voltage are an important tool to understand charge transfer processes in micropattern gas detectors like the Gas Electron Multiplier (GEM). They are currently used to e.g. optimize the field configuration in a multi-GEM stack to be used in the ALICE TPC after the upgrade of the experiment during the 2nd long shutdown of the LHC. Devices which allow measurements down to 1pA at high voltage up to 6 kV have been developed at TU Muenchen. They are based on analog current measurements via the voltage drop over a switchable shunt. A microcontroller collects 128 digital ADC values and calculates their mean and standard deviation. This information is sent with a wireless transmitting unit to a computer and stored in a root file. A nearly unlimited number of devices can be operated simultaneously and read out by a single receiver. The results can also be displayed on a LCD directly at the device. Battery operation and the wireless readout are important to protect the user from any contact to high voltage. The principle of the device is explained, and systematic studies of their properties are shown.

  19. Fuel Cell/Electrochemical Cell Voltage Monitor

    Science.gov (United States)

    Vasquez, Arturo

    2012-01-01

    A concept has been developed for a new fuel cell individual-cell-voltage monitor that can be directly connected to a multi-cell fuel cell stack for direct substack power provisioning. It can also provide voltage isolation for applications in high-voltage fuel cell stacks. The technology consists of basic modules, each with an 8- to 16-cell input electrical measurement connection port. For each basic module, a power input connection would be provided for direct connection to a sub-stack of fuel cells in series within the larger stack. This power connection would allow for module power to be available in the range of 9-15 volts DC. The relatively low voltage differences that the module would encounter from the input electrical measurement connection port, coupled with the fact that the module's operating power is supplied by the same substack voltage input (and so will be at similar voltage), provides for elimination of high-commonmode voltage issues within each module. Within each module, there would be options for analog-to-digital conversion and data transfer schemes. Each module would also include a data-output/communication port. Each of these ports would be required to be either non-electrical (e.g., optically isolated) or electrically isolated. This is necessary to account for the fact that the plurality of modules attached to the stack will normally be at a range of voltages approaching the full range of the fuel cell stack operating voltages. A communications/ data bus could interface with the several basic modules. Options have been identified for command inputs from the spacecraft vehicle controller, and for output-status/data feeds to the vehicle.

  20. A Test Study of 50% Lightning Impulse Breakdown Voltage on Rod-Plane Gap with Two-Phase Mixture of Gas and Solid Particles

    Science.gov (United States)

    He, Zhenghao; Xu, Huaili; Bai, Jing; Yu, Fusheng; Hu, Feng; Li, Jin

    2007-12-01

    A test study on 50% lightning impulse breakdown voltage in two-phase mixture of gas and solid particles has been carried out in a specially designed discharge cabinet. A mechanical sieve is set up for sifting different solid particles into the discharge space uniformly. The lightning impulse voltage according with international electro-technical commission (IEC) standard is applied to the electrodes inside the discharge cabinet by the rule of up-down method in a total of 40 times. The results showed that the 50% lightning impulse breakdown voltage in two-phase mixture of gas and solid particles has its own features and is much different from that in air.

  1. A threshold voltage model for high-κgate-dielectric MOSFETs considering fringing-field effect

    Institute of Scientific and Technical Information of China (English)

    Ji Feng; Xu Jing-Ping; Lai Pui-To

    2007-01-01

    In this paper, a threshold voltage model for high-κgate-dielectric metal-oxide-semiconductor field-effect transistors (MOSFETs) is developed, with more accurate boundary conditions of the gate dielectric derived through a conformal mapping transformation method to consider the fringing-field effects including the influences of high-κgate-dielectric and sidewall spacer. Comparing with similar models, the proposed model can be applied to general situations where the gate dielectric and sidewall spacer can have different dielectric constants. The influences of sidewall spacer and high-κgate dielectric on fringing field distribution of the gate dielectric and thus threshold voltage behaviours of a MOSFET are discussed in detail.

  2. Distributed Voltage Unbalance Compensation in Islanded Microgrids by Using Dynamic-Consensus-Algorithm

    DEFF Research Database (Denmark)

    Meng, Lexuan; Zhao, Xin; Tang, Fen;

    2016-01-01

    In islanded microgrids (MGs), distributed generators (DGs) can be employed as distributed compensators for improving the power quality in the consumer side. Two-level hierarchical control can be used for voltage unbalance compensation. Primary level, consisting of droop control and virtual...... impedance, can be applied to help the positive sequence active and reactive power sharing. Secondary level is used to assist voltage unbalance compensation. However, if distribution line differences are considered, the negative sequence current cannot be well shared among DGs. In order to overcome...

  3. Wetting patterns and bacterial distributions in different soils from a surface point source applying eflfuents with varyingEscherichia coliconcentrations

    Institute of Scientific and Technical Information of China (English)

    WEN Jie; LI Jiu-sheng; LI Yan-feng

    2016-01-01

    Understanding bacterial transportation in unsaturated soil is helpful for reducing and avoiding pathogenic contamination that may be induced by irrigation with reclaimed waste water and for developing better irrigation management practic-es. Experiments were conducted to study the transport of a typical bacterium,Escherichia coli (E. coli), in a sandy and a sandy loam soil under different application rates and input concentrations. A 30° wedge-shaped plexiglass container was used to represent one twelfth of the complete cylinder in the experiments. The apparent cylindrical application rate varied from 1.05 to 5.76 L h–1 and the input concentration ofE. coli from magnitude of 102 to 107 colony-forming unit (CFU) mL–1. For a given volume of water applied, an increase in application rate resulted in an increase in the wetted radius and a decrease in the wetted depth. In the sandy loam soil, the water spread out in a circular-arc shaped saturated zone on the surface, and the ultimate saturated entry radius increased with the application rate. An increasing application rate of water suspended bacteria alowed a more rapid transport of bacteria, thus acceleratingE. coli transport rate and resulting in a larger distributed volume ofE. coli for both soil types. For the sandy soil, more than 70% of theE. coli that was de-tected within the entire wetted volume concentrated in the range of 10 cm from the point source, and the concentration of E. colidecreased greatly as the distance from the point source increased. More than 98% of theE. coli was detected in a range of 5 cm around the saturated wetted zone for the sandy loam soil. For both soil types tested, an extremely high concentration ofE. coli was observed in the proximity of the point source, and the peak value increased with an increased input concentration. In principle, using an emitter with relative lower application rate would be effective to restrictE. coli transport. To reduce bacterial concentration in the

  4. Micro helical polymeric structures produced by variable voltage direct electrospinning

    NARCIS (Netherlands)

    Shariatpanahi, S.P.; Iraji zad, A.; Abdollahzadeh, I.; Shirsavar, R.; Bonn, D.; Ejtehadi, R.

    2011-01-01

    Direct near field electrospinning is used to produce very long helical polystyrene microfibers in water. The pitch length of helices can be controlled by changing the applied voltage, allowing the production of both microsprings and microchannels. Using a novel high frequency variable voltage electr

  5. Linear variable voltage diode capacitor and adaptive matching networks

    NARCIS (Netherlands)

    Larson, L.E.; De Vreede, L.C.N.

    2006-01-01

    An integrated variable voltage diode capacitor topology applied to a circuit providing a variable voltage load for controlling variable capacitance. The topology includes a first pair of anti-series varactor diodes, wherein the diode power-law exponent n for the first pair of anti-series varactor di

  6. Linear variable voltage diode capacitor and adaptive matching networks

    NARCIS (Netherlands)

    Larson, L.E.; De Vreede, L.C.N.

    2006-01-01

    An integrated variable voltage diode capacitor topology applied to a circuit providing a variable voltage load for controlling variable capacitance. The topology includes a first pair of anti-series varactor diodes, wherein the diode power-law exponent n for the first pair of anti-series varactor

  7. Virtual Admittance Loop for Voltage Harmonic Compensation in Microgrids

    DEFF Research Database (Denmark)

    Blanco, Cristian; Reigosa, David; Quintero, Juan Carlos Vasquez

    2016-01-01

    is that it can only be applied to distributed generation (DG) units operating in voltage control mode (VSI-VCM), but is not applicable to DG units working in current control mode (e.g. current regulated voltage source inverters, VSI-CCM). Contrary to this, the proposed method can be used in any converter...

  8. Virtual admittance loop for voltage harmonic compensation in microgrids

    DEFF Research Database (Denmark)

    Blanco, Cristian; Reigosa, David; Quintero, Juan Carlos Vasquez

    2015-01-01

    is that it can only be applied to distributed generation (DG) units operating in voltage control mode (VSI-VCM), but is not applicable to DG units working in current control mode (e.g. current regulated voltage source inverters, VSI-CCM or current source inverters, CSIs. Contrary to this, the proposed method can...

  9. Altitude Correction for Breakdown Voltages of Long Air-Gaps

    Institute of Scientific and Technical Information of China (English)

    Wang Xuan; Li Yunge; Cao Xiaolong; Su Zhiyi; Liu Ying

    2006-01-01

    The breakdown voltage of long air-gaps in high-voltage transmission systems depends on not only the waveform of the applied voltage, but also the atmospheric conditions. Based on the results of the research project on the minimum air clearance for 800-Kv HVDC substations at high altitudes, and also on the monthly and yearly statistics of the atmospheric data of last ten years and the altitude correction of the atmospheric data of last ten years, the altitude correction of the air-gaps for the 800-Kv DC system under plan, 500-Kv AC system to be built, and 1000-Kv AC system under plan in the Inner Mongolia Plateau and the Yungui Plateau in China were studied with parameter G method. Correction factors for switching and lightning impulses were calculated and then compared with those achieved according to IEC 71. It is shown that IEC 71 is appropriate for damp regions, and correction factors differ between plateau regions in China because of different atmospheric conditions.

  10. Voltage-dependent gating of hERG potassium channels

    Directory of Open Access Journals (Sweden)

    Yen May eCheng

    2012-05-01

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

  11. High voltage and electrical insulation engineering

    CERN Document Server

    Arora, Ravindra

    2011-01-01

    "The book is written for students as well as for teachers and researchers in the field of High Voltage and Insulation Engineering. It is based on the advance level courses conducted at TU Dresden, Germany and Indian Institute of Technology Kanpur, India. The book has a novel approach describing the fundamental concept of field dependent behavior of dielectrics subjected to high voltage. There is no other book in the field of high voltage engineering following this new approach in describing the behavior of dielectrics. The contents begin with the description of fundamental terminology in the subject of high voltage engineering. It is followed by the classification of electric fields and the techniques of field estimation. Performance of gaseous, liquid and solid dielectrics under different field conditions is described in the subsequent chapters. Separate chapters on vacuum as insulation and the lightning phenomenon are included"--

  12. Removal of phenol by activated alumina bed in pulsed high-voltage electric field

    Institute of Scientific and Technical Information of China (English)

    ZHU Li-nan; MA Jun; YANG Shi-dong

    2007-01-01

    A new process for removing the pollutants in aqueous solution-activated alumina bed in pulsed high-voltage electric field was investigated for the removal of phenol under different conditions. The experimental results indicated the increase in removal rate with increasing applied voltage, increasing pH value of the solution, aeration, and adding Fe2+. The removal rate of phenol could reach 72.1 % when air aeration flow rate was 1200 ml/min, and 88.2 % when 0.05 mmol/L Fe2+ was added into the solution under the conditions of applied voltage 25 kV, initial phenol concentration of 5 mg/L, and initial pH value 5.5. The addition of sodium carbonate reduced the phenol removal rate. In the pulsed high-voltage electric field, local discharge occurred at the surface of activated alumina, which promoted phenol degradation in the thin water film. At the same time, the space-time distribution of gas-liquid phases was more uniform and the contact areas of the activated species generated from the discharge and the pollutant molecules were much wider due to the effect of the activated alumina bed. The synthetical effects of the pulsed high-voltage electric field and the activated alumina particles accelerated phenol degradation.

  13. Voltage control in active, intelligent low-voltage distribution networks; Spannungshaltung in aktiven, intelligenten Niederspannungsnetzen

    Energy Technology Data Exchange (ETDEWEB)

    Buelo, Thorsten; Mende, Denis [SMA Solar Technology AG, Niestetal (Germany); Geibel, Dominik [Fraunhofer Institut fuer Windenergie und Energiesystemtechnik (IWES), Kassel (Germany)] [and others

    2012-07-01

    This paper describes approaches for the voltage control in low-voltage distribution networks with a high share of distributed energy resources (DER). Taken into account are devices such as distribution transformers with on-load tap changer (OLTC), photovoltaic-inverters with reactive power capability and electronic voltage controllers (EVC). After a short description regarding voltage control, the devices and selected system concepts as well as the advantages and disadvantages of the different devices are described. Finally, the system-concepts are compared using the example of a real low voltage network, taking into account the possible increase of hosting capacity of the network, curtailing losses and the amount of reactive energy to be provided. (orig.)

  14. Temporal difference learning for the game Tic-Tac-Toe 3D: Applying structure to neural networks

    NARCIS (Netherlands)

    Van De Steeg, Michiel; Drugan, Madalina M.; Wiering, Marco

    2016-01-01

    When reinforcement learning is applied to large state spaces, such as those occurring in playing board games, the use of a good function approximator to learn to approximate the value function is very important. In previous research, multi-layer perceptrons have often been quite successfully used as

  15. Voltage-controlled nanoscale reconfigurable magnonic crystal

    Science.gov (United States)

    Wang, Qi; Chumak, Andrii V.; Jin, Lichuan; Zhang, Huaiwu; Hillebrands, Burkard; Zhong, Zhiyong

    2017-04-01

    A nanoscale reconfigurable magnonic crystal is designed using voltage-controlled perpendicular magnetic anisotropy (PMA) in ferromagnetic-dielectric heterostructures. A periodic array of gate metallic strips is placed on top of a MgO/Co structure in order to apply a periodic electric field and to modify the PMA in Co. It is numerically demonstrated that the introduction of PMA, which can be realized experimentally via applying a voltage, modifies the spin-wave propagation and leads to the formation of band gaps in the spin-wave spectrum. The band gaps can be controlled, i.e., it is possible to switch band gaps on and off within a few tens of nanoseconds. The width and the center frequency of the band gaps are defined by the applied voltage. Finally, it is shown that the introduction of PMA to selected, rather than to all gate strips allows for a predefined modification of the band-gap spectra. The proposed voltage-controlled reconfigurable magnonic crystal opens a way to low power consumption magnonic applications.

  16. Breakdown voltage of metal-oxide resistors in liquid argon

    CERN Document Server

    Bagby, L F; James, C C; Jones, B J P; Jostlein, H; Lockwitz, S; Naples, D; Raaf, J L; Rameika, R; Schukraft, A; Strauss, T; Weber, M S; Wolbers, S A

    2014-01-01

    We characterized a sample of metal-oxide resistors and measured their breakdown voltage in liquid argon by applying high voltage (HV) pulses over a 3 second period to simulate the electric breakdown in a HV-divider chain. All resistors had higher breakdown voltages in liquid argon than their vendor ratings in air at room temperature. Failure modes range from full destruction to coating damage. In cases where breakdown was not catastrophic, subsequent breakdown voltages were lower in subsequent measuring runs. One resistor type withstands 131\\,kV pulses, the limit of the test setup.

  17. Voltage-gated proton (H(v)1) channels, a singular voltage sensing domain.

    Science.gov (United States)

    Castillo, Karen; Pupo, Amaury; Baez-Nieto, David; Contreras, Gustavo F; Morera, Francisco J; Neely, Alan; Latorre, Ramon; Gonzalez, Carlos

    2015-11-14

    The main role of voltage-gated proton channels (Hv1) is to extrude protons from the intracellular milieu when, mediated by different cellular processes, the H(+) concentration increases. Hv1 are exquisitely selective for protons and their structure is homologous to the voltage sensing domain (VSD) of other voltage-gated ion channels like sodium, potassium, and calcium channels. In clear contrast to the classical voltage-dependent channels, Hv1 lacks a pore domain and thus permeation necessarily occurs through the voltage sensing domain. Hv1 channels are activated by depolarizing voltages, and increases in internal proton concentration. It has been proposed that local conformational changes of the transmembrane segment S4, driven by depolarization, trigger the molecular rearrangements that open Hv1. However, it is still unclear how the electromechanical coupling is achieved between the VSD and the potential pore, allowing the proton flux from the intracellular to the extracellular side. Here we provide a revised view of voltage activation in Hv1 channels, offering a comparative scenario with other voltage sensing channels domains.

  18. Analyzing of Dynamic Voltage Restorer in Series Compensation Voltage

    Directory of Open Access Journals (Sweden)

    Naser Parhizgar

    2012-02-01

    Full Text Available The Dynamic Voltage Restorer (DVR is a series-connected compensator to generate a controllable voltage to against the short-term voltage disturbances. The technique of DVR is an effective and cost competitive approach to improve voltage quality at the load side. This study presents a single-phase and threephase DVR system with reduced switch-count topology to protect the sensitive load against abnormal voltage conditions. Most basic function, the DVR configuration consist of a two level Voltage Source Converter (VSC, a dc energy storage device, a coupling transformer Connected in shunt with the ac system This study presents the application of Dynamic Voltage Restorer (DVR on power distribution systems for mitigation of voltage sag at critical loads. DVR is one of the compensating types of custom power devices. The DVR, which is based on forced-commutated Voltage Source Converter (VSC has been proved suitable for the task of compensating voltage sags/swells. Simulation results are presented to illustrate and understand the performances of DVR in supporting load voltages under voltage sags/swells conditions.

  19. High Voltage Charge Pump

    KAUST Repository

    Emira, Ahmed A.

    2014-10-09

    Various embodiments of a high voltage charge pump are described. One embodiment is a charge pump circuit that comprises a plurality of switching stages each including a clock input, a clock input inverse, a clock output, and a clock output inverse. The circuit further comprises a plurality of pumping capacitors, wherein one or more pumping capacitors are coupled to a corresponding switching stage. The circuit also comprises a maximum selection circuit coupled to a last switching stage among the plurality of switching stages, the maximum selection circuit configured to filter noise on the output clock and the output clock inverse of the last switching stage, the maximum selection circuit further configured to generate a DC output voltage based on the output clock and the output clock inverse of the last switching stage.

  20. A thermoelectric voltage effect in polyethylene oxide

    CERN Document Server

    Martin, B; Kliem, H

    2003-01-01

    The conductivity of polyethylene oxide (PEO) is described with a three-dimensional hopping model considering electrostatic interactions between the ions. Ions fluctuate over energy-barriers in a multi-well potential. To decide whether positive or negative charges are responsible for this conductivity, the thermoelectric voltage is measured. The samples are embedded between two aluminium-electrodes. The oxide on the interface between the electrodes and the PEO serves as a blocking layer. The temperature of each electrode is controlled by a Peltier element. A temperature step is applied to one electrode by changing the temperature of one of the Peltier elements. Due to this temperature gradient, the mobile charges fluctuate thermally activated from the warmer side to the colder side of the sample. The direction of the measured thermoelectric voltage indicates the type of mobile charges. It is found that positive charges are mobile. Further, it is shown that the absolute value of the thermoelectric voltage depen...

  1. Semisupervised Community Detection by Voltage Drops

    Directory of Open Access Journals (Sweden)

    Min Ji

    2016-01-01

    Full Text Available Many applications show that semisupervised community detection is one of the important topics and has attracted considerable attention in the study of complex network. In this paper, based on notion of voltage drops and discrete potential theory, a simple and fast semisupervised community detection algorithm is proposed. The label propagation through discrete potential transmission is accomplished by using voltage drops. The complexity of the proposal is OV+E for the sparse network with V vertices and E edges. The obtained voltage value of a vertex can be reflected clearly in the relationship between the vertex and community. The experimental results on four real networks and three benchmarks indicate that the proposed algorithm is effective and flexible. Furthermore, this algorithm is easily applied to graph-based machine learning methods.

  2. Increased voltage photovoltaic cell

    Science.gov (United States)

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

    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.

  3. Thermal protection of β-carotene in re-assembled casein micelles during different processing technologies applied in food industry.

    Science.gov (United States)

    Sáiz-Abajo, María-José; González-Ferrero, Carolina; Moreno-Ruiz, Ana; Romo-Hualde, Ana; González-Navarro, Carlos J

    2013-06-01

    β-Carotene is a carotenoid usually applied in the food industry as a precursor of vitamin A or as a colourant. β-Carotene is a labile compound easily degraded by light, heat and oxygen. Casein micelles were used as nanostructures to encapsulate, stabilise and protect β-carotene from degradation during processing in the food industry. Self-assembly method was applied to re-assemble nanomicelles containing β-carotene. The protective effect of the nanostructures against degradation during the most common industrial treatments (sterilisation, pasteurisation, high hydrostatic pressure and baking) was proven. Casein micelles protected β-carotene from degradation during heat stabilisation, high pressure processing and the processes most commonly used in the food industry including baking. This opens new possibilities for introducing thermolabile ingredients in bakery products.

  4. Low-Voltage MOS Current Mode Logic Multiplexer

    Directory of Open Access Journals (Sweden)

    K. Gupta

    2013-04-01

    Full Text Available In this paper, a new low-voltage MOS current mode logic (MCML multiplexer based on the triple-tail cell concept is proposed. An analytical model for static parameters is formulated and is applied to develop a design approach for the proposed low-voltage MCML multiplexer. The delay of the proposed low-voltage MCML multiplexer is expressed in terms of the bias current and the voltage swing so that it can be traded off with the power consumption. The proposed low-voltage MCML multiplexer is analyzed for the three design cases namely high-speed, power-efficient, and low-power. Finally, a comparison in performance of the proposed low-voltage MCML multiplexer with the traditional MCML multiplexer is carried out for all the cases.

  5. Planar LTCC transformers for high voltage flyback converters.

    Energy Technology Data Exchange (ETDEWEB)

    Schofield, Daryl (NASCENT Technology Inc. , Watertown, SD); Schare, Joshua M.; Glass, Sarah Jill; Roesler, Alexander William; Ewsuk, Kevin Gregory; Slama, George (NASCENT Technology Inc. , Watertown, SD); Abel, Dave (NASCENT Technology Inc. , Watertown, SD)

    2007-06-01

    This paper discusses the design and use of low-temperature (850 C to 950 C) co-fired ceramic (LTCC) planar magnetic flyback transformers for applications that require conversion of a low voltage to high voltage (> 100V) with significant volumetric constraints. Measured performance and modeling results for multiple designs showed that the LTCC flyback transformer design and construction imposes serious limitations on the achievable coupling and significantly impacts the transformer performance and output voltage. This paper discusses the impact of various design factors that can provide improved performance by increasing transformer coupling and output voltage. The experiments performed on prototype units demonstrated LTCC transformer designs capable of greater than 2 kV output. Finally, the work investigated the effect of the LTCC microstructure on transformer insulation. Although this paper focuses on generating voltages in the kV range, the experimental characterization and discussion presented in this work applies to designs requiring lower voltage.

  6. Advances in high voltage power switching with GTOs

    Energy Technology Data Exchange (ETDEWEB)

    Podlesak, T.F. (US Army Electronic Technology and Devices Lab., Fort Monmouth, NJ (US)); McMurray, J.A. (Vitronics, Eatontown, NJ (US)); Carter, J.L.

    1990-12-01

    The control of high voltage at high power, particularly opening switches, has been difficult in the past. Using gate turnoff thyristors (GTOs) arranged in series enables large currents to be switched at high voltage. A high voltage opening switch has been successfully demonstrated in our laboratory. This switch uses GTOs in series and successfully operates at voltages higher than the rated voltage of the individual devices. It is believed that this is the first time this has been successfully demonstrated, in that GTOs have been operated in series before, but always in a manner as to not exceed the voltage capability of the individual devices. In short, the devices have not worked together, sharing the voltage, but one device has been operated using several backup devices. Of particular interest is how well the individual devices share the voltage applied to them. Equal voltage sharing between devices is absolutely essential, in order to not exceed the voltage rating of any of the devices in the series chain. This is accomplished at high (microsecond) switching speeds. Thus, the system is useful for high frequency applications as well as high power, making for a flexible circuit system element. This paper reports on this demonstration system that is rated at 5 KV and uses 1 KV devices. A larger 24 KV system is under design and will use 4.5 KV devices. In order to design the 24 KV switch, the safe operating area of the large devices must be known thoroughly.

  7. SIMULATION OF INTERLINE DYNAMIC VOLTAGE RESTORER

    Directory of Open Access Journals (Sweden)

    J.Singaravelan

    2011-08-01

    Full Text Available This paper presents a new approach for the dynamic control of a current source inverter (CSI using Super Conductive Magnetic energy storage (SMES based Interline DVR. The dynamic voltage restorer (DVR provides a technically advanced and economical solution to voltage-sag problem. As the voltage-restoration process involves the real-power injection into the distribution system, the capability ofa DVR, especially for compensating long-duration voltage sags, it depends on the energy storage capacity of the DVR. The interline DVR proposed in this paper provides a way to replenish Dc-link energy storage dynamically. The IDVR consists of several DVRs connected to different distribution feeders in the power system. The DVRs in the IDVR system shares the common energy storage. When one of the DVRcompensates for voltage sag appearing in that feeder, the other DVRs replenish the energy in the common dc-link dynamically. Thus, one DVR in the IDVR system works in voltage-sag compensation mode whilethe other DVRs in the IDVR system operate in power-flow control mode. The proposed topology is simulated using Matlab/Simulink and total IDVR system is simulated using Matlab/Simulink.

  8. Experimental validation of prototype high voltage bushing

    Science.gov (United States)

    Shah, Sejal; Tyagi, H.; Sharma, D.; Parmar, D.; M. N., Vishnudev; Joshi, K.; Patel, K.; Yadav, A.; Patel, R.; Bandyopadhyay, M.; Rotti, C.; Chakraborty, A.

    2017-08-01

    Prototype High voltage bushing (PHVB) is a scaled down configuration of DNB High Voltage Bushing (HVB) of ITER. It is designed for operation at 50 kV DC to ensure operational performance and thereby confirming the design configuration of DNB HVB. Two concentric insulators viz. Ceramic and Fiber reinforced polymer (FRP) rings are used as double layered vacuum boundary for 50 kV isolation between grounded and high voltage flanges. Stress shields are designed for smooth electric field distribution. During ceramic to Kovar brazing, spilling cannot be controlled which may lead to high localized electrostatic stress. To understand spilling phenomenon and precise stress calculation, quantitative analysis was performed using Scanning Electron Microscopy (SEM) of brazed sample and similar configuration modeled while performing the Finite Element (FE) analysis. FE analysis of PHVB is performed to find out electrical stresses on different areas of PHVB and are maintained similar to DNB HV Bushing. With this configuration, the experiment is performed considering ITER like vacuum and electrical parameters. Initial HV test is performed by temporary vacuum sealing arrangements using gaskets/O-rings at both ends in order to achieve desired vacuum and keep the system maintainable. During validation test, 50 kV voltage withstand is performed for one hour. Voltage withstand test for 60 kV DC (20% higher rated voltage) have also been performed without any breakdown. Successful operation of PHVB confirms the design of DNB HV Bushing. In this paper, configuration of PHVB with experimental validation data is presented.

  9. Unified Power Quality Conditioner for voltage and current compensation

    Directory of Open Access Journals (Sweden)

    P.Annapandi

    2012-07-01

    Full Text Available This paper deals with a Unified Power Quality Conditioner (UPQC for load balancing, power factorcorrection, voltage regulation, voltage and current harmonics mitigation, mitigation of voltage sag, swelland voltage dip in a three-phase three-wire distribution system for different combinations of linear and nonlinear loads.The unified power quality conditioner (UPQC is a combination of back to back connected shunt and series active power filters (APFs to a common DC link voltage, which compensates voltage and current based distortions, independently.Using instantaneous active and reactive Power theory ,harmonic detection, reactive power compensation, voltage sag and swell have been simulated and the results are analyzed. The operation and capability of the proposed system was analyzed through simulations with MATLAB / SIMULINK.

  10. Voltage charging enhances ionic conductivity in gold nanotube membranes.

    Science.gov (United States)

    Gao, Peng; Martin, Charles R

    2014-08-26

    Ionically conductive membranes are used in many electrochemical processes and devices, including batteries, fuel cells, and electrolyzers. In all such applications, it is advantageous to use membranes with high ionic conductivity because membrane resistance causes a voltage loss suffered by the cell. We describe here a method for enhancing ionic conductivity in membranes containing small diameter (4 nm) gold nanotubes. This entails making the gold nanotube membrane the working electrode in an electrochemical cell and applying a voltage to the membrane. We show here that voltage charging in this way can increase membrane ionic conductivity by over an order of magnitude. When expressed in terms of the ionic conductivity of the electrolyte, κ, within an individual voltage-charged tube, the most negative applied voltage yielded a κ comparable to that of 1 M aqueous KCl, over 2 orders of magnitude higher than κ of the 0.01 M KCl solution contacting the membrane.

  11. Voltage Controlled Dynamic Demand Response

    DEFF Research Database (Denmark)

    Bhattarai, Bishnu Prasad; Bak-Jensen, Birgitte; Mahat, Pukar

    2013-01-01

    . An adaptive dynamic model has been developed to determine composite voltage dependency of an aggregated load on feeder level. Following the demand dispatch or control signal, optimum voltage setting at the LV substation is determined based on the voltage dependency of the load. Furthermore, a new technique...

  12. Charge-pump voltage converter

    Science.gov (United States)

    Brainard, John P.; Christenson, Todd R.

    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.

  13. Active voltage contrast imaging of cross-sectional surface of multilayer ceramic capacitor using helium ion microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Sakai, C., E-mail: SAKAI.Chikako@nims.go.jp; Ishida, N.; Masuda, H.; Nagano, S.; Kitahara, M.; Fujita, D. [National Institute for Materials Science, Tsukuba, Ibaraki 305-0047 (Japan); Ogata, Y. [TAIYO YUDEN CO., LTD., Takasaki-shi, Gunma 370-3347 (Japan)

    2016-08-01

    We studied active voltage contrast (AVC) imaging using helium ion microscopy (HIM). We observed secondary electron (SE) images of the cross-sectional surface of multilayer ceramic capacitors (MLCCs) with and without a voltage applied to the internal electrodes. When no voltage was applied, we obtained an image reflecting the material contrast between the Ni internal electrode region and the BaTiO{sub 3} dielectric region of the cross-sectional surface of the MLCC. When a voltage was applied, the electrical potential difference between the grounded and the positively biased internal electrodes affected the contrast (voltage contrast). Moreover, attenuation of the SE intensity from the grounded to the positively biased internal electrodes was observed in the dielectric region. Kelvin probe force microscopy (KPFM) measurements of the contact potential difference (CPD) were performed on the same sample. By using the AVC image from the HIM observation and the CPD image from the KPFM measurement, we could quantitatively evaluate the electrical potential. We think that the results of this study will lead to an expansion in the number of applications of HIM.

  14. Effect of genetic algorithm as a variable selection method on different chemometric models applied for the analysis of binary mixture of amoxicillin and flucloxacillin: A comparative study

    Science.gov (United States)

    Attia, Khalid A. M.; Nassar, Mohammed W. I.; El-Zeiny, Mohamed B.; Serag, Ahmed

    2016-03-01

    Different chemometric models were applied for the quantitative analysis of amoxicillin (AMX), and flucloxacillin (FLX) in their binary mixtures, namely, partial least squares (PLS), spectral residual augmented classical least squares (SRACLS), concentration residual augmented classical least squares (CRACLS) and artificial neural networks (ANNs). All methods were applied with and without variable selection procedure (genetic algorithm GA). The methods were used for the quantitative analysis of the drugs in laboratory prepared mixtures and real market sample via handling the UV spectral data. Robust and simpler models were obtained by applying GA. The proposed methods were found to be rapid, simple and required no preliminary separation steps.

  15. Multi-Inputs/Multi-Outputs control of plasma current and loop voltage on Tore Supra

    Energy Technology Data Exchange (ETDEWEB)

    Nouailletas, R., E-mail: remy.nouailletas@cea.fr [CEA, F-13108 Saint Paul lez Durance (France); Barana, O.; Saint-Laurent, F.; Brémond, S.; Moreau, P.; Ekedahl, A.; Artaud, J.-F. [CEA, F-13108 Saint Paul lez Durance (France)

    2013-10-15

    During a tokamak discharge, several control modes may have to be run in sequence in order to perform the control of the different discharge phases. The transitions between these control modes are not always easy to handle because in most cases the coupling between the controlled plasma quantities is not taken into account in each control mode design process. This paper presents a new Multi-Inputs/Multi-Outputs (MIMO) controller applied on Tore Supra to control both plasma current and flux variations through the central solenoid voltage and the lower hybrid current drive (LHCD) system power. It deals with the transition from a loop voltage floating mode to a loop voltage control mode. The controller, synthesized and tuned using a model-based approach, has been validated in simulation before its successful implementation on Tore Supra experiments.

  16. The k-ε-fP model applied to double wind turbine wakes using different actuator disk force methods

    DEFF Research Database (Denmark)

    Laan, van der, Paul Maarten; Sørensen, Niels N.; Réthoré, Pierre-Elouan

    2015-01-01

    The newly developed k-ε-fP  eddy viscosity model is applied to double wind turbine wake configurations in a neutral atmospheric boundary layer, using a Reynolds-Averaged Navier–Stokes solver. The wind turbines are represented by actuator disks. A proposed variable actuator disk force method...... is employed to estimate the power production of the interacting wind turbines, and the results are compared with two existing methods: a method based on tabulated airfoil data and a method based on the axial induction from 1D momentum theory. The proposed method calculates the correct power, while the other...... two methods overpredict it. The results of the k-ε-fP  eddy viscosity model are also compared with the original k-ε eddy viscosity model and large-eddy simulations. Compared to the large-eddy simulations-predicted velocity and power deficits, the k-ε-fP  is superior to the original k-ε model...

  17. Segment Orientation and Optical Birefringence of Amorphous Polymers Under Tensile Deformation: Novel Computational Method applied to Different Glassy Polycarbonates

    Science.gov (United States)

    Natarajan, Upendra; Sulatha, M. S.

    2005-03-01

    Orientation dependent optical properties of Bisphenol A polycarbonate and two aliphatic substituted polycarbonates in glassy phase have been studied by atomistic modeling using molecular mechanics simulations under tensile deformation. Probability distributions and orientation functions show that phenylene rings and carbonate groups vectors along the main chain orient towards stretching direction following deformation. Interchain packing of rings and carbonates become ordered with strain. Efficient computational approach for calculation of optical birefringence of amorphous polymers is presented and applied to the polycarbonates in detail. Polarizability anisotropy of the polymer segments and chain as a function of deformation is calculated by combining information on the conformations and group polarizabilities, and used to estimate birefringence during deformation. Simulated and experimental values for segment orientation and bulk birefringence are in very good agreement. Effect of the optical properties of atomic groups on bulk birefringence is brought forth for the first time by molecular simulation for polymers other than polyethylene.

  18. No-Voltage Meter

    Science.gov (United States)

    1976-02-01

    VW- IKft, 1/4 H4 -Wv- IK!1, I/4W INTERNAL VOLTAGE NOTE ALL TRANSISTORS ARE 2N43A OR EQUIVALENT GERMANIUM ALLOY PNP AA ALKALINE BATTERY...D-,, regardless of polarity. This signal is then full-wave rectified by the diode-connected Germanium transistor bridge, T,, T-,, T3, and T4... Transistor T5 acts as a second current limiter. Resistor R2 was selected to give 90 f# of full-scale meter deflection with an input signal of 115 volts

  19. Benchmarking of Voltage Sag Generators

    DEFF Research Database (Denmark)

    Yang, Yongheng; Blaabjerg, Frede; Zou, Zhixiang

    2012-01-01

    The increased penetration of renewable energy systems, like photovoltaic and wind power systems, rises the concern about the power quality and stability of the utility grid. Some regulations for Low Voltage Ride-Through (LVRT) for medium voltage or high voltage applications, are coming into force...... to guide these grid-connected distributed power generation systems. In order to verify the response of such systems for voltage disturbance, mainly for evaluation of voltage sags/dips, a Voltage Sag Generator (VSG) is needed. This paper evaluates such sag test devices according to IEC 61000 in order...... to provide cheaper solutions to test against voltage sags. Simulation and experimental results demonstrate that the shunt impedance based VSG solution is the easiest and cheapest one for laboratory test applications. The back-to-back fully controlled converter based VSG is the most flexible solution...

  20. 不同风电场模型对风电场电压的影响评估%Assessment on the effect of different kinds of wind farm models on wind farm voltage

    Institute of Scientific and Technical Information of China (English)

    赵海岭; 王维庆; 常喜强

    2011-01-01

    目前,实际的电力系统仿真计算将风电场处理为一台风电机组.随着并入输电网的风电容量持续增加,仍按照一台风机等效对系统仿真计算造成的误差不容忽视,该误差能引起风电场内部保护装置的误动作.文章针对不同风电模型对风电场电压的影响做了详细比较,并给出了量化指标.经过试验仿真分析得出以下结论:不同风电场模型对风电场出口和并网点电压的影响不同,当恒速异步风电机构成的风电场采用一台风电机等效时,将会使风电场出口的相电压计算平均误差达到16.667%.因此,为保证仿真精度与风电场保护的正确动作,在对含风电场的电力系统进行仿真计算时,应将风电场处理为若干台风电机.%At present, the simulation calculation for practical power system is usually carried out by regarding the wind farm as one wind power unit. Along with the increase of the grid connected wind power capacity, the error caused by simulation calculation on one equivalent wind turbine should not be neglected, the error may result in the misoperation of the internal protecting device in the wind farm. The paper carried out the detailed comparison on the effect of different kinds of wind farm models on wind farm voltage, and gave the quantitative index. By means of computer simulation analysis, several conclusions are drawn: different kinds of wind farm models make different effects on voltage of wind farm and point of common coupling (PCC). When regard the constant speed induction motor based wind farm as one wind power generator, the average calculation error of the phase voltage at the terminal of the wind farm could reach a value of 16.776%. As a result, for guaranteeing the simulation accuracy and the right operation of the wind farm protection device, it should regards the wind farm as several wind power units when carrying out the simulation on power system.

  1. Capturing power at higher voltages from arrays of microbial fuel cells without voltage reversal

    KAUST Repository

    Kim, Younggy

    2011-01-01

    Voltages produced by microbial fuel cells (MFCs) cannot be sustainably increased by linking them in series due to voltage reversal, which substantially reduces stack voltages. It was shown here that MFC voltages can be increased with continuous power production using an electronic circuit containing two sets of multiple capacitors that were alternately charged and discharged (every one second). Capacitors were charged in parallel by the MFCs, but linked in series while discharging to the circuit load (resistor). The parallel charging of the capacitors avoided voltage reversal, while discharging the capacitors in series produced up to 2.5 V with four capacitors. There were negligible energy losses in the circuit compared to 20-40% losses typically obtained with MFCs using DC-DC converters to increase voltage. Coulombic efficiencies were 67% when power was generated via four capacitors, compared to only 38% when individual MFCs were operated with a fixed resistance of 250 Ω. The maximum power produced using the capacitors was not adversely affected by variable performance of the MFCs, showing that power generation can be maintained even if individual MFCs perform differently. Longer capacitor charging and discharging cycles of up to 4 min maintained the average power but increased peak power by up to 2.6 times. These results show that capacitors can be used to easily obtain higher voltages from MFCs, allowing for more useful capture of energy from arrays of MFCs. © 2011 The Royal Society of Chemistry.

  2. Applying a Danish version of the Learning Transfer System Inventory and testing it for different types of education

    DEFF Research Database (Denmark)

    Sørensen, Peter; Stegeager, Nikolaj W.M.; Bates, Reid

    2017-01-01

    The purpose of this study was to answer two research questions. First, will an exploratory factor analysis of a Danish version of the Learning Transfer System Inventory (LTSI) result in a factor structure which is consistent with the original American LTSI factor structure? Second, does the mean...... in the original American LTSI. The study also found that the mean score differs in a statistically significant way between the different types of education. Specifically, LTSI may be more suitable in measuring transfer systems and therefore promoting transfer in relation to short courses offering training...

  3. A random resistor network model of voltage trimming

    Energy Technology Data Exchange (ETDEWEB)

    Grimaldi, C [Laboratoire de Production Microtechnique, Ecole Polytechnique Federale de Lausanne, CH-1015 Lausanne (Switzerland); Maeder, T [Laboratoire de Production Microtechnique, Ecole Polytechnique Federale de Lausanne, CH-1015 Lausanne (Switzerland); Ryser, P [Laboratoire de Production Microtechnique, Ecole Polytechnique Federale de Lausanne, CH-1015 Lausanne (Switzerland); Straessler, S [Laboratoire de Production Microtechnique, Ecole Polytechnique Federale de Lausanne, CH-1015 Lausanne (Switzerland)

    2004-08-07

    In industrial applications, the controlled adjustment (trimming) of resistive elements via the application of high voltage pulses is a promising technique, with several advantages with respect to more classical approaches such as the laser cutting method. The microscopic processes governing the response to high voltage pulses depend on the nature of the resistor and on the interaction with the local environment. Here we provide a theoretical statistical description of voltage discharge effects on disordered composites by considering random resistor network models with different properties and processes due to the voltage discharge. We compare standard percolation results with biased percolation effects and provide a tentative explanation of the different scenarios observed during trimming processes.

  4. Improvement of the JRC Calculation Using Different Parameters Obtained Through a New Survey Method Applied to Rock Discontinuities

    Science.gov (United States)

    Alameda-Hernández, Pedro; Jiménez-Perálvarez, Jorge; Palenzuela, José A.; El Hamdouni, Rachid; Irigaray, Clemente; Cabrerizo, Miguel A.; Chacón, José

    2014-11-01

    This paper presents a new, fast and economical method for digitizing a rock surface profile to determine its joint roughness coefficient (JRC) value (Barton and Choubey, Rock Mech Rock Eng 10:1-54, 1977) using a set of existing parameters, the appropriateness of which has been tested. The new procedure was applied to four rock road cuts in the Alpujarra area of Granada province (Andalusia, Spain), supported by 117 digitized profiles. The method avoids any personal subjectivity bias. The usual subjectivity in the visualization and assessment of the JRC value is estimated here by a survey test answered by 90 trained users. The survey test consisted of a set of JRC visual comparisons of 12 roughness profiles, selected from the 117 profiles surveyed during the field research in the Alpujarra region, with the Barton typical profiles. The results of the survey clearly show systematic inaccuracies in the traditional procedure that are reduced if the advice presented in the conclusions of this paper is taken in account when performing the visual estimation.

  5. Essential Attributes of the Accounting Information in Applying The Financial Reporting Differences Between Ifrs and us Gaap

    Directory of Open Access Journals (Sweden)

    Herbei Ioana

    2015-05-01

    Full Text Available In the context of the development of information, the main role of financial reporting is threatened by alternative sources of information that users use. However, the main source of information for decision-makers remain the accounting information relaxed from synthesis financial reporting, because the legal framework prescribes mandatory minimum information and a set of quality certification mechanisms thereof. As a starting point in our research we used relevant studies from the scientific literature regarding the understanding of the accounting information in financial reporting. We specify that many authors place the accounting information in the perimeter of the objectivity and the accuracy, which is essential in making economic decisions by the leadership. Thus, in support of decisionmakers, accountants apply professional judgment (judgment of International Financial Reporting Standards, taking decisions in terms of the use of accounting treatments to achieve a quality of financial reporting information. The contents of the article have been reported not only attributes on accounting information provided by IFRS, but also aspects of US GAAP regarding financial reporting, presenting the differentiation between the two accounting referential. We note that the accounting information can be the best friend of actual and potential investors if used properly understood

  6. A continuous time delay-difference type model (CTDDM) applied to stock assessment of the southern Atlantic albacore Thunnus alalunga

    Science.gov (United States)

    Liao, Baochao; Liu, Qun; Zhang, Kui; Baset, Abdul; Memon, Aamir Mahmood; Memon, Khadim Hussain; Han, Yanan

    2016-09-01

    A continuous time delay-diff erence model (CTDDM) has been established that considers continuous time delays of biological processes. The southern Atlantic albacore ( Thunnus alalunga) stock is the one of the commercially important tuna population in the marine world. The age structured production model (ASPM) and the surplus production model (SPM) have already been used to assess the albacore stock. However, the ASPM requires detailed biological information and the SPM lacks the biological realism. In this study, we focus on applying a CTDDM to the southern Atlantic albacore ( T. alalunga) species, which provides an alternative method to assess this fishery. It is the first time that CTDDM has been provided for assessing the Atlantic albacore ( T. alalunga) fishery. CTDDM obtained the 80% confidence interval of MSY (maximum sustainable yield) of (21 510 t, 23 118t). The catch in 2011 (24 100 t) is higher than the MSY values and the relative fishing mortality ratio ( F 2011/ F MSY) is higher than 1.0. The results of CTDDM were analyzed to verify the proposed methodology and provide reference information for the sustainable management of the southern Atlantic albacore stock. The CTDDM treats the recruitment, the growth, and the mortality rates as all varying continuously over time and fills gaps between ASPM and SPM in this stock assessment.

  7. The evaluation of four different diffuse radiation correction models applied to shadow ring measurements for Beer Sheva, Israel

    Science.gov (United States)

    Kudish, Avraham I.; Evseev, Efim G.

    2007-09-01

    The measurement of the horizontal diffuse radiation, a priori a straightforward task, is fraught with difficulties. It is possible to measure the diffuse radiation by both direct and indirect methods. The most accurate method is probably the indirect one, which utilizes concurrent measurements of the horizontal global and the normal incidence beam radiation. The disadvantage of this method is the relatively expensive tracking system required for measuring the latter. The diffuse radiation can be measured directly with a pyranometer outfitted with either an occulting disk or shadow ring, which prevent the beam radiation from impinging on the pyranometer sensor. The former method can provide accurate measurements of the diffuse radiation but requires a relatively expensive sun tracking system in the east-west axis. The shadow ring is a stationary device with regard to the east-west axis and blocks the beam radiation component by creating a permanent shadow on the pyranometer sensor. The disadvantage of the shadow ring is that it also blocks a portion of the sky, which necessitates a geometrical correction factor. There is also a need to correct for anisotropic sky conditions. Four correction models have been applied to the data and the results evaluated and ranked.

  8. Evaluation of different toxicity assays applied to proliferating cells and to stratified epithelium in relation to permeability enhancement with glycocholate

    DEFF Research Database (Denmark)

    Eirheim, Heidi Ugelstad; Bundgaard, Christoffer; Nielsen, Hanne Mørck

    2004-01-01

    exposed to different GC concentrations for 4 h. The MTS/PMS assay and neutral red (NR) retention were performed along with quantitation of ATP, lactate dehydrogenase (LDH) and extracellular protein. The toxicity was calculated as the IC50 value relative to the control. Increase in 3H-mannitol permeability...

  9. A comparative study for Triple-Rule-out with different tube voltage technique of Dual-Source CT in acute chest pain%双源 CT不同管电压技术诊断急性胸痛三联症效果比较

    Institute of Scientific and Technical Information of China (English)

    王皆欢; 陈东风; 王少春; 孙占国; 王林省; 张谷青

    2014-01-01

    目的:对比双源CT胸痛三联检查在两种不同电压下显示急性胸痛患者肺动脉、主动脉及冠状动脉的图像质量以及患者所受的辐射剂量,以评估低电压扫描在急性胸痛患者推广应用的可行性。方法利用双源C T胸痛三联扫描模式,结合回顾性心电门控技术对361例胸痛三联检查患者进行统计分析,比较主动脉、肺动脉及冠状动脉的图像质量及辐射的有效剂量。结果120kV组与100kV组在图像质量的主观评分对比中差异无统计学意义(P>0.05),在患者辐射剂量的对比中,120kV组的辐射剂量大于100kV组,差异有统计学意义(P<0.05)。结论双源CT胸痛三联检查两种不同管电压扫描对急性胸痛患者的肺动脉、主动脉及冠状动脉的成像质量无影响,并且应用100kV 管电压扫描可以降低患者所受的辐射剂量,可以作为急性胸痛患者的首选。%Objective To compare the value of triple-rule-out (TRO) dual-source computed tomography angiog-raphy in acute chest pain patients with diseases of pulmonary artery ,aortic and coronary artery and radiation dose in two different voltage as well as the feasibility of generalizing and applying in patients with acute chest pain . Methods 361 patients with chest pain were analyzed statistically underwent triple-rule-out (TRO) dual-source CT combined with retrospective ECG-gated technique ,and then compare with image quality of aorta ,pulmonary artery and coronary artery and effective radiation dose .Results Subjective score of image quality of the voltage 120kV and 100kV group had no statistical significance(P>0.05) .The difference was statistically significant(P<0.05)in comparison of radiation dose .The effective radiation dose of the voltage 100kV group was lower than that of the voltage 120kV group .Conclusion The quality of pictures of pulmonary artery ,coronary artery and aorta are not affected in different tube tension

  10. Two-Terminal Fault Location for Four-Circuit Transmission System Composed of Two Double-Circuit Transmission Lines on Same Towers Respectively Belonging to Different Voltage Grades%不同电压等级四回线双端故障测距原理研究

    Institute of Scientific and Technical Information of China (English)

    李月乔; 王君

    2012-01-01

    由于存在互感和故障类型众多,不同电压等级四回线的故障分析和故障测距愈加困难。为此采用六序分量矩阵叠加方法对不同电压等级的四回线进行解耦,可以将阻抗阵转换为一个特殊的对角阵,非对角线上不为零的元素只有2个,表明四回线的同向零序网存在互感,其它的非对角线元素为零,表明四回线的反向正序网之间不存在互感。采用六序分量矩阵叠加方法对四回线系统的2条同杆双回线两端的电流分别进行矩阵变换,得到2组反向正序电流,利用反向正序电压在故障点相等I坷特点,实现不同电压等级四回线的双端故障测距。该双端故障测距方法不需要考虑不同电压等级同杆双回线的参数归算,测距精度不受故障类型、故障点过渡电阻、系统运行方式的影响。仿真结果表明,该双端故障测距方法具有有效性和实用性。%Due to the existence of mutual inductances and various types of faults, it is more difficult in fault analysis and fault location for four-circuit transmission system composed of two double-circuit transmission lines on same towers respectively belonging to different voltage grades. For this reason, the superposition of two six-sequence component matrices is adopted to decompose the four-circuit transmission lines respectively belonging to two different voltage grades, thus the impedance matrix can be turned into a special diagonal matrix and only two nonzero elements on non-diagonals and this suggests that there is mutual inductance in the synclastic zero-sequence network of the four-circuit transmission system. Applying matrix transformation to currents at both terminals of the two double-circuit transmission lines on same towers in the four-circuit transmission system, two sets of reverse positive sequence currents are attained, then based on the feature that at fault point the reverse positive-sequence voltages

  11. Coordinated Voltage Control of Distributed PV Inverters for Voltage Regulation in Low Voltage Distribution Networks

    DEFF Research Database (Denmark)

    Nainar, Karthikeyan; Pokhrel, Basanta Raj; Pillai, Jayakrishnan Radhakrishna

    2017-01-01

    This paper reviews and analyzes the existing voltage control methods of distributed solar PV inverters to improve the voltage regulation and thereby the hosting capacity of a low-voltage distribution network. A novel coordinated voltage control method is proposed based on voltage sensitivity...... analysis, which is simple for computation and requires moderate automation and communication infrastructure. The proposed method is suitable for a hierarchical control structure where a supervisory controller has the provision to adapt the settings of local PV inverter controllers for overall system...

  12. Heat-pump performance: voltage dip/sag, under-voltage and over-voltage

    Directory of Open Access Journals (Sweden)

    William J.B. Heffernan

    2014-12-01

    Full Text Available Reverse cycle air-source heat-pumps are an increasingly significant load in New Zealand and in many other countries. This has raised concern over the impact wide-spread use of heat-pumps may have on the grid. The characteristics of the loads connected to the power system are changing because of heat-pumps. Their performance during under-voltage events such as voltage dips has the potential to compound the event and possibly cause voltage collapse. In this study, results from testing six heat-pumps are presented to assess their performance at various voltages and hence their impact on voltage stability.

  13. Comparison of different approaches applied in Analytic Hierarchy Process - an example of information needs of patients with rare diseases.

    Science.gov (United States)

    Pauer, Frédéric; Schmidt, Katharina; Babac, Ana; Damm, Kathrin; Frank, Martin; von der Schulenburg, J-Matthias Graf

    2016-09-09

    The Analytic Hierarchy Process (AHP) is increasingly used to measure patient priorities. Studies have shown that there are several different approaches to data acquisition and data aggregation. The aim of this study was to measure the information needs of patients having a rare disease and to analyze the effects of these different AHP approaches. The ranking of information needs is then used to display information categories on a web-based information portal about rare diseases according to the patient's priorities. The information needs of patients suffering from rare diseases were identified by an Internet research study and a preliminary qualitative study. Hence, we designed a three-level hierarchy containing 13 criteria. For data acquisition, the differences in outcomes were investigated using individual versus group judgements separately. Furthermore, we analyzed the different effects when using the median and arithmetic and geometric means for data aggregation. A consistency ratio ≤0.2 was determined to represent an acceptable consistency level. Forty individual and three group judgements were collected from patients suffering from a rare disease and their close relatives. The consistency ratio of 31 individual and three group judgements was acceptable and thus these judgements were included in the study. To a large extent, the local ranks for individual and group judgements were similar. Interestingly, group judgements were in a significantly smaller range than individual judgements. According to our data, the ranks of the criteria differed slightly according to the data aggregation method used. It is important to explain and justify the choice of an appropriate method for data acquisition because response behaviors differ according to the method. We conclude that researchers should select a suitable method based on the thematic perspective or investigated topics in the study. Because the arithmetic mean is very vulnerable to outliers, the geometric mean

  14. The antimicrobial sensitivity of Streptococcus mutans and Streptococcus sangius to colloidal solutions of different nanoparticles applied as mouthwashes

    Directory of Open Access Journals (Sweden)

    Farzaneh Ahrari

    2015-01-01

    Full Text Available Background: Metal nanoparticles have been recently applied in dentistry because of their antibacterial properties. This study aimed to evaluate antibacterial effects of colloidal solutions containing zinc oxide (ZnO, copper oxide (CuO, titanium dioxide (TiO 2 and silver (Ag nanoparticles on Streptococcus mutans and Streptococcus sangius and compare the results with those of chlorhexidine and sodium fluoride mouthrinses. Materials and Methods: After adding nanoparticles to a water-based solution, six groups were prepared. Groups I to IV included colloidal solutions containing nanoZnO, nanoCuO, nanoTiO 2 and nanoAg, respectively. Groups V and VI consisted of 2.0% sodium fluoride and 0.2% chlorhexidine mouthwashes, respectively as controls. We used serial dilution method to find minimum inhibitory concentrations (MICs and with subcultures obtained minimum bactericidal concentrations (MBCs of the solutions against S. mutans and S. sangius. The data were analyzed by analysis of variance and Duncan test and P < 0.05 was considered as significant. Results: The sodium fluoride mouthrinse did not show any antibacterial effect. The nanoTiO 2 -containing solution had the lowest MIC against both microorganisms and also displayed the lowest MBC against S. mutans (P < 0.05. The colloidal solutions containing nanoTiO 2 and nanoZnO showed the lowest MBC against S. sangius (P < 0.05. On the other hand, chlorhexidine showed the highest MIC and MBC against both streptococci (P < 0.05. Conclusion: The nanoTiO 2 -containing mouthwash proved to be an effective antimicrobial agent and thus it can be considered as an alternative to chlorhexidine or sodium fluoride mouthrinses in the oral cavity provided the lack of cytotoxic and genotoxic effects on biologic tissues.

  15. Battery powered high output voltage bidirectional flyback converter for cylindrical DEAP actuator

    DEFF Research Database (Denmark)

    Huang, Lina; Thummala, Prasanth; Zhang, Zhe;

    2012-01-01

    DEAP (Dielectric Electro Active Polymer) actuator is essentially a capacitive load and can be applied in various actuation occasions. However, high voltage is needed to actuate it. In this paper, a high voltage bidirectional flyback converter with low input voltage is presented. The fundamental....... The design parameters for flyback transformer and snubber circuits are illustrated. Moreover, the experimental waveforms are provided....

  16. Newton's method applied to finite-difference approximations for the steady-state compressible Navier-Stokes equations

    Science.gov (United States)

    Bailey, Harry E.; Beam, Richard M.

    1991-01-01

    Finite-difference approximations for steady-state compressible Navier-Stokes equations, whose two spatial dimensions are written in generalized curvilinear coordinates and strong conservation-law form, are presently solved by means of Newton's method in order to obtain a lifting-airfoil flow field under subsonic and transonnic conditions. In addition to ascertaining the computational requirements of an initial guess ensuring convergence and the degree of computational efficiency obtainable via the approximate Newton method's freezing of the Jacobian matrices, attention is given to the need for auxiliary methods assessing the temporal stability of steady-state solutions. It is demonstrated that nonunique solutions of the finite-difference equations are obtainable by Newton's method in conjunction with a continuation method.

  17. Applying full multigroup cell characteristics from MCU code to finite difference calculations of neutron field in VVER core

    Energy Technology Data Exchange (ETDEWEB)

    Gorodkov, S.S.; Kalugin, M.A. [Nuclear Research Centre ' ' Kurchatov Institute' ' , Moscow (Russian Federation)

    2015-09-15

    Up to now core calculations with Monte Carlo provided only average cross-sections of mesh cells for further use either in finite difference calculations or as benchmark ones for approximate spectral algorithms. Now MCU code is capable to handle functions, which may be interpreted as average diffusion coefficients. Subsequently the results of finite difference calculations with cells characteristic sets obtained in such a way can be compared with Monte Carlo results as benchmarks, giving reliable information on quality of production code under consideration. As an example of such analysis, the results of mesh calculations with 1-, 2-, 4-, 8- and 12 neutron groups of some model VVER fuel assembly are presented in comparison with the exact Monte Carlo solution. As a second example, an analysis is presented of water gap approximate enlargement between fuel assemblies, allowing VVER core region be covered by regular mesh.

  18. Applying the Triangle Taste Test to Assess Differences between Low Sodium Salts and Common Salt: Evidence from Peru

    Science.gov (United States)

    Saavedra-Garcia, Lorena; Bernabe-Ortiz, Antonio; Gilman, Robert H.; Diez-Canseco, Francisco; Cárdenas, María Kathia; Sacksteder, Katherine A.; Miranda, J. Jaime

    2015-01-01

    Background In resourced-constrained settings, daily cooking practices are still the norm. Replacing sodium in regular salt to produce potassium-enriched salts are potential alternative routes to reduce sodium intake, paired with the benefit associated with potassium intake. This change would likely have effects on palatability and taste of prepared foods, yet a threshold to discriminate sensorial changes can be determined. The main goal of this study was to assess if the use of potassium-enriched salt substitutes lead to perceived differences in taste utilizing a sensory discrimination test. Methods and Results A triangle taste test was conducted and participants were offered samples of cooked rice prepared with different salts. The only ingredient that differed in the preparation was the salt used: 100%NaCl (regular salt) and salts where sodium was replaced by 50%, 33% or 25% KCl (potassium-enriched salt). Comparisons were carried out according to the minimum number of correct judgments. A total of 156 subjects, 49% males, mean age 41.0 years (SD±15.5) years, participated in the study. Samples using 25% potassium-enrichment were indistinguishable in terms of taste from regular salt, whereas samples with 33% and 50% potassium-enrichment were distinguishable. Results were consistent when stratified by sex and age. Less than 10% of participants attributed the differences to bitterness or metallic flavor. Conclusions The 25% potassium-enriched salt is indistinguishable from regular salt. These findings suggest a potential to achieve sodium intake reduction strategies in cooking practices by substituting regular salt with potassium-enriched salt without affecting palatability. PMID:26225848

  19. Correlation peak analysis applied to a sequence of images using two different filters for eye tracking model

    Science.gov (United States)

    Patrón, Verónica A.; Álvarez Borrego, Josué; Coronel Beltrán, Ángel

    2015-09-01

    Eye tracking has many useful applications that range from biometrics to face recognition and human-computer interaction. The analysis of the characteristics of the eyes has become one of the methods to accomplish the location of the eyes and the tracking of the point of gaze. Characteristics such as the contrast between the iris and the sclera, the shape, and distribution of colors and dark/light zones in the area are the starting point for these analyses. In this work, the focus will be on the contrast between the iris and the sclera, performing a correlation in the frequency domain. The images are acquired with an ordinary camera, which with were taken images of thirty-one volunteers. The reference image is an image of the subjects looking to a point in front of them at 0° angle. Then sequences of images are taken with the subject looking at different angles. These images are processed in MATLAB, obtaining the maximum correlation peak for each image, using two different filters. Each filter were analyzed and then one was selected, which is the filter that gives the best performance in terms of the utility of the data, which is displayed in graphs that shows the decay of the correlation peak as the eye moves progressively at different angle. This data will be used to obtain a mathematical model or function that establishes a relationship between the angle of vision (AOV) and the maximum correlation peak (MCP). This model will be tested using different input images from other subject not contained in the initial database, being able to predict angle of vision using the maximum correlation peak data.

  20. Stability Analysis and Controller Synthesis for Single-Loop Voltage-Controlled VSIs

    DEFF Research Database (Denmark)

    Wang, Xiongfei; Loh, Poh Chiang; Blaabjerg, Frede

    2017-01-01

    This paper analyzes the stability of the digital single-loop voltage-controlled Voltage-Source Inverters (VSIs) using linear voltage regulators. It reveals that the phase lags caused by using the resonant controller and the time delay of digital control system can stabilize the voltage loop without...... damping of the LC-filter resonance. The stability region for the digital single-loop resonant voltage control is then identified considering the effects of the discretization methods applied to the resonant controller. An enhanced voltage control scheme with widened stability region is subsequently...

  1. Comparison among GPR measurements and ultrasonic tomographies with different inversion strategies applied to the basement of an ancient egyptian sculpture.

    Science.gov (United States)

    Sambuelli, Luigi; Bohm, Gualtiero; Capizzi, Patrizia; Cardarelli, Ettore; Cosentino, Pietro; D'Onofrio, Laurent; Marchisio, Mario

    2010-05-01

    By the late 2008 one of the most important pieces of the "Museo delle Antichità Egizie" in Turin, the sculpture of the Pharaoh with god Amun, was planned to be one of the masterpieces of a travelling exhibition in Japan. The "Fondazione Museo delle Antichità Egizie di Torino", managing the museum, was concerned with the integrity of the basement of the statue which actually presents visible signs of restorations dating back to the early IXX century. The questions put by the museum managers were to estimate the internal extension of some visible fractures, to search for unknown internal ones and to provide information about the overall mechanical strength of the basement. In order to tackle the first and second questions a GPR reflection survey of the basement along three sides was performed and the results were assembled in a 3D rendering. As far as the third question is concerned, two parallel, horizontal ultrasonic 2D tomographies across the basement were made with a source-receiver layout able to acquire, for each section, 723 ultrasonic signals correspondent to different transmitter and receiver positions. The ultrasonic tomographic data were inverted using different software based upon different algorithms. The obtained velocity images were then compared with the GPR results and with the visible joints on the basement. A critical analysis of the comparisons is finally presented.

  2. Applying a System Dynamics Approach for Modeling Groundwater Dynamics to Depletion under Different Economical and Climate Change Scenarios

    Directory of Open Access Journals (Sweden)

    Hamid Balali

    2015-09-01

    Full Text Available In the recent decades, due to many different factors, including climate change effects towards be warming and lower precipitation, as well as some structural policies such as more intensive harvesting of groundwater and low price of irrigation water, the level of groundwater has decreased in most plains of Iran. The objective of this study is to model groundwater dynamics to depletion under different economic policies and climate change by using a system dynamics approach. For this purpose a dynamic hydro-economic model which simultaneously simulates the farmer’s economic behavior, groundwater aquifer dynamics, studied area climatology factors and government economical policies related to groundwater, is developed using STELLA 10.0.6. The vulnerability of groundwater balance is forecasted under three scenarios of climate including the Dry, Nor and Wet and also, different scenarios of irrigation water and energy pricing policies. Results show that implementation of some economic policies on irrigation water and energy pricing can significantly affect on groundwater exploitation and its volume balance. By increasing of irrigation water price along with energy price, exploitation of groundwater will improve, in so far as in scenarios S15 and S16, studied area’s aquifer groundwater balance is positive at the end of planning horizon, even in Dry condition of precipitation. Also, results indicate that climate change can affect groundwater recharge. It can generally be expected that increases in precipitation would produce greater aquifer recharge rates.

  3. A comparison of different NDE signal processing techniques based on waveform entropies applied to long fiber-graphite/epoxy-plates

    Science.gov (United States)

    Larche, Michael; Prowant, Mathew; Bruillard, Paul; Hagge, Tobias; Fifield, Leonard S.; Hughes, Michael; Sun, Xin

    2017-04-01

    This study compares different approaches for imaging the internal architecture of graphite/epoxy composites using backscattered ultrasound. Two cases are studied. In the first, near-surface defects in a thin graphite/epoxy plates are imaged. The backscattered waveforms were used to produce peak-to-peak, logarithm of signal energy, as well as entropy images of different types. All of the entropy images exhibit better border delineation and defect contrast than either the peak-to-peak or the logarithm of signal energy. The best results are obtained using the joint entropy of the backscattered waveforms with a reference function. Two different references are examined. The first is a reflection of the insonifying pulse from a stainless steel reflector. The second is an approximate optimum obtained from an iterative parametric search. The joint entropy images produced using this reference exhibit three times the contrast obtained in previous studies. These plates were later destructively analyzed to determine size and location of near-surface defects and the results are found to agree with the defect location and shape as indicated by the entropy images. In the second study, images of long carbon fibers (50% by weight) in polypropylene thermoplastic were obtained as a first step toward ultrasonic determination of the distributions of fiber position and orientation.

  4. A Comparison of Different NDE Signal Processing Techniques Based on Waveform Entropies Applied to Long Fiber Graphite/Epoxy Plates

    Energy Technology Data Exchange (ETDEWEB)

    Larche, Michael R.; Prowant, Matthew S.; Bruillard, Paul J.; Hagge, Tobias J.; Fifield, Leonard S.; Hughes, Michael S.; Sun, Xin

    2017-04-19

    This study compares different approaches for imaging the internal architecture of graphite/epoxy composites using backscattered ultrasound. Two cases are studied. In the first, near-surface defects in a thin graphite/epoxy plates are imaged. The same backscattered waveforms were used to produce peak-to-peak, logarithm of signal energy, as well as entropy images of different types. All of the entropy images exhibit better border delineation and defect contrast than the either peak-to-peak or logarithm of signal energy. The best results are obtained using the joint entropy of the backscattered waveforms with a reference function. Two different references are examined. The first is a reflection of the insonifying pulse from a stainless steel reflector. The second is an approximate optimum obtained from an iterative parametric search. The joint entropy images produced using this reference exhibit three times the contrast obtained in previous studies. These plates were later destructively analyzed to determine size and location of near-surface defects and the results found to agree with the defect location and shape as indicated by the entropy images. In the second study, images of long carbon graphite fibers (50% by weight) in polypropylene thermoplastic are obtained as a first step toward ultrasonic determination of the distributions of fiber position and orientation.

  5. Dynamic memory of a single voltage-gated potassium ion channel: A stochastic nonequilibrium thermodynamic analysis

    Energy Technology Data Exchange (ETDEWEB)

    Banerjee, Kinshuk, E-mail: kbpchem@gmail.com [Department of Chemistry, University of Calcutta, 92 A.P.C. Road, Kolkata 700 009 (India)

    2015-05-14

    In this work, we have studied the stochastic response of a single voltage-gated potassium ion channel to a periodic external voltage that keeps the system out-of-equilibrium. The system exhibits memory, resulting from time-dependent driving, that is reflected in terms of dynamic hysteresis in the current-voltage characteristics. The hysteresis loop area has a maximum at some intermediate voltage frequency and disappears in the limits of low and high frequencies. However, the (average) dissipation at long-time limit increases and finally goes to saturation with rising frequency. This raises the question: how diminishing hysteresis can be associated with growing dissipation? To answer this, we have studied the nonequilibrium thermodynamics of the system and analyzed different thermodynamic functions which also exhibit hysteresis. Interestingly, by applying a temporal symmetry analysis in the high-frequency limit, we have analytically shown that hysteresis in some of the periodic responses of the system does not vanish. On the contrary, the rates of free energy and internal energy change of the system as well as the rate of dissipative work done on the system show growing hysteresis with frequency. Hence, although the current-voltage hysteresis disappears in the high-frequency limit, the memory of the ion channel is manifested through its specific nonequilibrium thermodynamic responses.

  6. Isomerically Pure Tetramethylrhodamine Voltage Reporters.

    Science.gov (United States)

    Deal, Parker E; Kulkarni, Rishikesh U; Al-Abdullatif, Sarah H; Miller, Evan W

    2016-07-27

    We present the design, synthesis, and application of a new family of fluorescent voltage indicators based on isomerically pure tetramethylrhodamines. These new Rhodamine Voltage Reporters, or RhoVRs, use photoinduced electron transfer (PeT) as a trigger for voltage sensing, display excitation and emission profiles in the green to orange region of the visible spectrum, demonstrate high sensitivity to membrane potential changes (up to 47% ΔF/F per 100 mV), and employ a tertiary amide derived from sarcosine, which aids in membrane localization and simultaneously simplifies the synthetic route to the voltage sensors. The most sensitive of the RhoVR dyes, RhoVR 1, features a methoxy-substituted diethylaniline donor and phenylenevinylene molecular wire at the 5'-position of the rhodamine aryl ring, exhibits the highest voltage sensitivity to date for red-shifted PeT-based voltage sensors, and is compatible with simultaneous imaging alongside green fluorescent protein-based indicators. The discoveries that sarcosine-based tertiary amides in the context of molecular-wire voltage indicators prevent dye internalization and 5'-substituted voltage indicators exhibit improved voltage sensitivity should be broadly applicable to other types of PeT-based voltage-sensitive fluorophores.

  7. A Microscopic Capacitor Model of Voltage Coupling in Membrane Proteins: Gating Charge Fluctuations in Ci-VSD.

    Science.gov (United States)

    Kim, Ilsoo; Warshel, Arieh

    2016-01-28

    The voltage sensitivity of membrane proteins is reflected in the response of the voltage sensing domains (VSDs) to the changes in membrane potential. This response is implicated in the displacement of positively charged residues, associated with the conformational changes of VSDs. The displaced charges generate nonlinear (i.e., voltage-dependent) capacitance current called the gating current (and its corresponding gating charge), which is a key experimental quantity that characterizes voltage activation in VSMP. However, the relevant theoretical/computational approaches, aimed to correlate the structural information on VSMP to electrophysiological measurements, have been rather limited, posing a broad challenge in computer simulations of VSMP. Concomitant with the development of our coarse-graining (CG) model of voltage coupling, we apply our theoretical framework for the treatments of voltage effects in membrane proteins to modeling the VSMP activation, taking the VSDs (Ci-VSD) derived from the Ciona intestinalis voltage sensitive phosphatase (Ci-VSP) as a model system. Our CG model reproduces the observed gating charge of Ci-VSD activation in several different perspectives. In particular, a new closed-form expression of the gating charge is evaluated in both nonequilibrium and equilibrium ways, while considering the fluctuation-dissipation relation that connects a nonequilibrium measurement of the gating charge to an equilibrium measurement of charge fluctuations (i.e., the voltage-independent linear component of membrane capacitance). In turn, the expression uncovers a novel link that connects an equilibrium measurement of the voltage-independent linear capacitance to a nonequilibrium measurement of the voltage-dependent nonlinear capacitance (whose integral over voltage is equal to the gating charge). In addition, our CG model yields capacitor-like voltage dependent free energy parabolas, resulting in the free energy difference and the free energy barrier for

  8. A Decentralized Control Method for Distributed Generations in an Islanded DC Microgrid Considering Voltage Drop Compensation and Durable State of Charge

    Directory of Open Access Journals (Sweden)

    Chul-Sang Hwang

    2016-12-01

    Full Text Available This paper presents a decentralized control method for distributed generations (DGs in an islanded direct current (DC microgrid. In most typical DC microgrids, a decentralized control method is based on a voltage droop control method. However, the grid voltage differs from node to node due to line voltage drop, and hence the power sharing ratio among DGs cannot be matched with as desired value. Especially in an islanded DC microgrid including an energy storage system as a voltage source, it is difficult for DGs to maintain the charge state of the ESS in a decentralized way. To overcome this problem, state of charge (SOC-voltage droop control is applied to the ESS. By using the proposed droop method, the SOC information can be assigned to the grid voltage, and hence the other DGs are able to support the SOC in a decentralized way. For DGs to enhance the accuracy of the SOC estimation, voltage drop is compensated for based on forecasting data and line impedance data. The simulation is modeled and implemented using Power System Computer Aided Design/Electromagnetic Transients for DC (PSCAD/EMTDC, version 4.2, Winnipeg, Manitoba, Canada and the simulation results show that the capability to maintain SOC as well as the system voltage profile are improved by using the proposed method.

  9. Developing and applying quantitative skills maps for STEM curricula, with a focus on different modes of learning

    Science.gov (United States)

    Reid, Jackie; Wilkes, Janelle

    2016-08-01

    Mapping quantitative skills across the science, technology, engineering and mathematics (STEM) curricula will help educators identify gaps and duplication in the teaching, practice and assessment of the necessary skills. This paper describes the development and implementation of quantitative skills mapping tools for courses in STEM at a regional university that offers both on-campus and distance modes of study. Key elements of the mapping project included the identification of key graduate quantitative skills, the development of curriculum mapping tools to record in which unit(s) and at what level of attainment each quantitative skill is taught, practised and assessed, and identification of differences in the way quantitative skills are developed for on-campus and distance students. Particular attention is given to the differences that are associated with intensive schools, which consist of concentrated periods of face-to-face learning over a three-four day period, and are available to distance education students enrolled in STEM units. The detailed quantitative skills mapping process has had an impact on the review of first-year mathematics units, resulted in crucial changes to the curriculum in a number of courses, and contributed to a more integrated approach, and a collective responsibility, to the development of students' quantitative skills for both face-to-face and online modes of learning.

  10. Bacterial Leakage Assessment for Different Types of Resin-Based Dental Restorations Applied Using Various Placement Methods

    Directory of Open Access Journals (Sweden)

    Horieh Moosavi

    2014-09-01

    Full Text Available Introduction: Although composite resins have improved greatly since their introduction, microleakage is one of the most frequently encountered problems. This study compared the effects of different monomer systems and layering techniques on the bacterial leakage of Cl I composite resin restorations. Methods: Eighty-two sound human third molars were used. The teeth were randomly divided into six groups of 12 teeth each and two positive and negative control groups of five teeth. Class I cavities, measuring 4×4×2 mm, were prepared. The first three groups were filled with a silorane-based composite (Filtek P90 using three different methods of filling (bulk, incremental and snowplow and the remaining three groups were filled with a methacrylate-based composite (Clearfil AP-X using the same techniques. The specimens were stored for 24 hours at 37°C and then thermocycled up to 1000 cycles. The bacterial leakage of the specimens was assessed in a microbiological laboratory and statistical analyses of data were performed by Fisher’s exact and chi-squared tests (P0.05. Conclusion: Leakage occurred similarly in both silorane- and methacrylate-based composite resins and three filling techniques.  

  11. A Modified Equation Approach to Selecting a Nonstandard Finite Difference Scheme Applied to the Regularized Long Wave Equation

    Directory of Open Access Journals (Sweden)

    E. Momoniat

    2014-01-01

    Full Text Available Two nonstandard finite difference schemes are derived to solve the regularized long wave equation. The criteria for choosing the “best” nonstandard approximation to the nonlinear term in the regularized long wave equation come from considering the modified equation. The two “best” nonstandard numerical schemes are shown to preserve conserved quantities when compared to an implicit scheme in which the nonlinear term is approximated in the usual way. Comparisons to the single solitary wave solution show significantly better results, measured in the L2 and L∞ norms, when compared to results obtained using a Petrov-Galerkin finite element method and a splitted quadratic B-spline collocation method. The growth in the error when simulating the single solitary wave solution using the two “best” nonstandard numerical schemes is shown to be linear implying the nonstandard finite difference schemes are conservative. The formation of an undular bore for both steep and shallow initial profiles is captured without the formation of numerical instabilities.

  12. A novel method to measure the generated voltage of a ZnO nanogenerator

    Energy Technology Data Exchange (ETDEWEB)

    Heever, Stanley T van den; Buettner, Ulrich; Perold, Willem J, E-mail: tsvdh@sun.ac.za [Department of Electrical and Electronic Engineering, Stellenbosch University, Cnr Banghoek Road and Joubert Street, 7600, Stellenbosch (South Africa)

    2011-09-30

    A novel method to measure the output voltage of a zinc oxide nanowire nanogenerator is proposed. Various tests are performed to verify that the output voltage does indeed originate from the nanogenerator and not from environmental noise. Although noise does influence the output voltage measurements, the output voltage is easily distinguishable from the measured noise. It is also shown that the method can be used to determine the internal resistance of the nanogenerator by measuring the output voltage over different output resistors.

  13. Evaluation of lightning-induced voltages on low-voltage distribution networks

    Energy Technology Data Exchange (ETDEWEB)

    Silveira, Fernando H.; Visacro, Silverio [Federal University of Minas Gerais (LRC/UFMG), Belo Horizonte, MG (Brazil). Lightning Research Center], Emails: silveira@cpdee.ufmg.br, visacro@cpdee.ufmg.br

    2007-07-01

    This paper presents a set of evaluations concerning lightning-induced voltages on low-voltage networks. Such evaluations were performed by means of the Hybrid Electromagnetic Model, a frequency-domain code based on electromagnetic field equations. Sensitivity analyses were developed in order to investigate the role played by the most relevant line parameters on the voltages induced along the electrical system and at the consumer service entrance. The performance of two different low voltage line configurations (conventional versus multiplexed) usually adopted in Brazil was also investigated. The obtained results constitute a contribution to this theme and also provide elements to the development of protection practices to the electrical system and to the consumer against such phenomenon. (author)

  14. Current-voltage characteristics and transition voltage spectroscopy of individual redox proteins.

    Science.gov (United States)

    Artés, Juan M; López-Martínez, Montserrat; Giraudet, Arnaud; Díez-Pérez, Ismael; Sanz, Fausto; Gorostiza, Pau

    2012-12-19

    Understanding how molecular conductance depends on voltage is essential for characterizing molecular electronics devices. We reproducibly measured current-voltage characteristics of individual redox-active proteins by scanning tunneling microscopy under potentiostatic control in both tunneling and wired configurations. From these results, transition voltage spectroscopy (TVS) data for individual redox molecules can be calculated and analyzed statistically, adding a new dimension to conductance measurements. The transition voltage (TV) is discussed in terms of the two-step electron transfer (ET) mechanism. Azurin displays the lowest TV measured to date (0.4 V), consistent with the previously reported distance decay factor. This low TV may be advantageous for fabricating and operating molecular electronic devices for different applications. Our measurements show that TVS is a helpful tool for single-molecule ET measurements and suggest a mechanism for gating of ET between partner redox proteins.

  15. Simulation of 20-channel, 50-GHz, Si3N4-based arrayed waveguide grating applying three different photonics tools

    Science.gov (United States)

    Gajdošová, Lenka; Seyringer, Dana

    2017-02-01

    We present the design and simulation of 20-channel, 50-GHz Si3N4 based AWG using three different commercial photonics tools, namely PHASAR from Optiwave Systems Inc., APSS from Apollo Photonics Inc. and RSoft from Synopsys Inc. For this purpose we created identical waveguide structures and identical AWG layouts in these tools and performed BPM simulations. For the simulations the same calculation conditions were used. These AWGs were designed for TM-polarized light with an AWG central wavelength of 850 nm. The output of all simulations, the transmission characteristics, were used to calculate the transmission parameters defining the optical properties of the simulated AWGs. These parameters were summarized and compared with each other. The results feature very good correlation between the tools and are comparable to the designed parameters in AWG-Parameters tool.

  16. High voltage testing for the MAJORANA DEMONSTRATOR

    Energy Technology Data Exchange (ETDEWEB)

    Abgrall, N. [Nuclear Science Division, Lawrence Berkeley National Laboratory, Berkeley, CA (United States); Arnquist, I.J. [Pacific Northwest National Laboratory, Richland, WA (United States); Avignone, F.T. [Department of Physics and Astronomy, University of South Carolina, Columbia, SC (United States); Oak Ridge National Laboratory, Oak Ridge, TN (United States); Barabash, A.S. [National Research Center “Kurchatov Institute” Institute for Theoretical and Experimental Physics, Moscow (Russian Federation); Bertrand, F.E. [Oak Ridge National Laboratory, Oak Ridge, TN (United States); Bradley, A.W. [Nuclear Science Division, Lawrence Berkeley National Laboratory, Berkeley, CA (United States); Brudanin, V. [Joint Institute for Nuclear Research, Dubna (Russian Federation); Busch, M. [Department of Physics, Duke University, Durham, NC (United States); Triangle Universities Nuclear Laboratory, Durham, NC (United States); Buuck, M. [Center for Experimental Nuclear Physics and Astrophysics, and Department of Physics, University of Washington, Seattle, WA (United States); Byram, D. [Department of Physics, University of South Dakota, Vermillion, SD (United States); Caldwell, A.S. [South Dakota School of Mines and Technology, Rapid City, SD (United States); Chan, Y-D. [Nuclear Science Division, Lawrence Berkeley National Laboratory, Berkeley, CA (United States); Christofferson, C.D. [South Dakota School of Mines and Technology, Rapid City, SD (United States); Chu, P.-H. [Los Alamos National Laboratory, Los Alamos, NM (United States); Cuesta, C., E-mail: ccuesta@uw.edu [Center for Experimental Nuclear Physics and Astrophysics, and Department of Physics, University of Washington, Seattle, WA (United States); Detwiler, J.A.; Doe, P.J. [Center for Experimental Nuclear Physics and Astrophysics, and Department of Physics, University of Washington, Seattle, WA (United States); and others

    2016-07-01

    The MAJORANA Collaboration is constructing the MAJORANA DEMONSTRATOR, an ultra-low background, 44-kg modular high-purity Ge (HPGe) detector array to search for neutrinoless double-beta decay in {sup 76}Ge. The phenomenon of surface micro-discharge induced by high-voltage has been studied in the context of the MAJORANA DEMONSTRATOR. This effect can damage the front-end electronics or mimic detector signals. To ensure the correct performance, every high-voltage cable and feedthrough must be capable of supplying HPGe detector operating voltages as high as 5 kV without exhibiting discharge. R&D measurements were carried out to understand the testing system and determine the optimum design configuration of the high-voltage path, including different improvements of the cable layout and feedthrough flange model selection. Every cable and feedthrough to be used at the MAJORANA DEMONSTRATOR was characterized and the micro-discharge effects during the MAJORANA DEMONSTRATOR commissioning phase were studied. A stable configuration has been achieved, and the cables and connectors can supply HPGe detector operating voltages without exhibiting discharge.

  17. High voltage testing for the MAJORANA DEMONSTRATOR

    Science.gov (United States)

    Abgrall, N.; Arnquist, I. J.; Avignone, F. T.; Barabash, A. S.; Bertrand, F. E.; Bradley, A. W.; Brudanin, V.; Busch, M.; Buuck, M.; Byram, D.; Caldwell, A. S.; Chan, Y.-D.; Christofferson, C. D.; Chu, P.-H.; Cuesta, C.; Detwiler, J. A.; Doe, P. J.; Dunagan, C.; Efremenko, Yu.; Ejiri, H.; Elliott, S. R.; Fu, Z.; Galindo-Uribarri, A.; Giovanetti, G. K.; Goett, J.; Green, M. P.; Gruszko, J.; Guinn, I. S.; Guiseppe, V. E.; Henning, R.; Hoppe, E. W.; Howard, S.; Howe, M. A.; Jasinski, B. R.; Keeter, K. J.; Kidd, M. F.; Konovalov, S. I.; Kouzes, R. T.; LaFerriere, B. D.; Leon, J.; Li, A.; MacMullin, J.; Martin, R. D.; Massarczyk, R.; Meijer, S. J.; Mertens, S.; Orrell, J. L.; O'Shaughnessy, C.; Poon, A. W. P.; Radford, D. C.; Rager, J.; Rielage, K.; Robertson, R. G. H.; Romero-Romero, E.; Shanks, B.; Shirchenko, M.; Snyder, N.; Suriano, A. M.; Tedeschi, D.; Thompson, A.; Ton, K. T.; Trimble, J. E.; Varner, R. L.; Vasilyev, S.; Vetter, K.; Vorren, K.; White, B. R.; Wilkerson, J. F.; Wiseman, C.; Xu, W.; Yakushev, E.; Yu, C.-H.; Yumatov, V.

    2016-07-01

    The MAJORANA Collaboration is constructing the MAJORANA DEMONSTRATOR, an ultra-low background, 44-kg modular high-purity Ge (HPGe) detector array to search for neutrinoless double-beta decay in 76Ge. The phenomenon of surface micro-discharge induced by high-voltage has been studied in the context of the MAJORANA DEMONSTRATOR. This effect can damage the front-end electronics or mimic detector signals. To ensure the correct performance, every high-voltage cable and feedthrough must be capable of supplying HPGe detector operating voltages as high as 5 kV without exhibiting discharge. R&D measurements were carried out to understand the testing system and determine the optimum design configuration of the high-voltage path, including different improvements of the cable layout and feedthrough flange model selection. Every cable and feedthrough to be used at the MAJORANA DEMONSTRATOR was characterized and the micro-discharge effects during the MAJORANA DEMONSTRATOR commissioning phase were studied. A stable configuration has been achieved, and the cables and connectors can supply HPGe detector operating voltages without exhibiting discharge.

  18. High voltage testing for the Majorana Demonstrator

    Energy Technology Data Exchange (ETDEWEB)

    Abgrall, N.; Arnquist, Isaac J.; Avignone, F. T.; Barabash, A.; Bertrand, F.; Bradley, A. W.; Brudanin, V.; Busch, Matthew; Buuck, M.; Byram, D.; Caldwell, A. S.; Chan, Yuen-Dat; Christofferson, C. D.; Chu, Pamela M.; Cuesta, C.; Detwiler, Jason A.; Doe, P. J.; Dunagan, C.; Efremenko, Yuri; Ejiri, H.; Elliott, S. R.; Fu, Z.; Galindo-Uribarri, A.; Giovanetti, G. K.; Goett, J.; Green, M. P.; Gruszko, J.; Guinn, I.; Guiseppe, V. E.; Henning, R.; Hoppe, Eric W.; Howard, S.; Howe, M. A.; Jasinski, B. R.; Keeter, K.; Kidd, M. F.; Konovalov, S.; Kouzes, Richard T.; Laferriere, Brian D.; Leon, Jonathan D.; Li, Alexander D.; MacMullin, J.; Martin, R. D.; Massarcyk, R.; Meijer, S. J.; Mertens, S.; Orrell, John L.; O' Shaughnessy, C.; Poon, Alan W.; Radford, D. C.; Rager, J.; Rielage, Keith; Robertson, R. G. H.; Romero Romo, M.; Shanks, B.; Shirchenko, M.; Snyder, N.; Suriano, Anne-Marie E.; Tedeschi, D.; Thompson, Andrew; Ton, K. T.; Trimble, J. E.; Varner, R. L.; Vasilyev, Sergey; Vetter, Kai; Vorren, Kris R.; White, Brandon R.; Wilkerson, J. F.; Wiseman, C.; Xu, W.; Yakushev, E.; Yu, Chang-Hong; Yumatov, V.

    2016-07-01

    The Majorana Collaboration is constructing theMajorana Demonstrator, an ultra-low background, 44-kg modular high-purity Ge (HPGe) detector array to search for neutrinoless double-beta decay in 76Ge. The phenomenon of surface micro-discharge induced by high-voltage has been studied in the context of theMajorana Demonstrator. This effect can damage the front-end electronics or mimic detector signals. To ensure the correct performance, every high-voltage cable and feedthrough must be capable of supplying HPGe detector operating voltages as high as 5 kV without exhibiting discharge. R&D measurements were carried out to understand the testing system and determine the optimum design configuration of the high-voltage path, including different improvements of the cable layout and feedthrough flange model selection. Every cable and feedthrough to be used at the Majorana Demonstrator was characterized and the micro-discharge effects during theMajorana Demonstrator commissioning phase were studied. A stable configuration has been achieved, and the cables and connectors can supply HPGe detector operating voltages without exhibiting discharge.

  19. Infrared thermography applied to the evaluation of metabolic heat loss of chicks fed with different energy densities

    Directory of Open Access Journals (Sweden)

    VMOS Ferreira

    2011-06-01

    Full Text Available Brazil must comply with international quality standards and animal welfare requirements in order to maintain its position as world's largest exporter of poultry meat. With the scenario of global climate change there is the forecast of occurrence of extreme events with characteristics of both excess cold and heat for several regions of the country. This study aimed to evaluate the effectiveness of using images of infrared thermography to evaluate the loss of sensible heat in young broilers fed different dietary energy levels. Twenty birds were reared in a house with appropriate brooding using infrared lamps. Birds were distributed in a completely randomized experimental into two treatments: T1 (control diet with 2950 kcal ME/kg-1, and T2 (high-energy diet with 3950 kcal ME/kg-1. Infrared thermographic images of the birds were recorded for four consecutive days. One bird was randomly chosen per treatment, and had special images taken and analyzed. Average surface temperature of the body area was calculated using the surface temperature recorded at 100 spots (50 at the front and 50 at the lateral side of the bird's body. Mean surface temperature of the flock was calculated recording 100 spots on the group of birds. Total radiant heat loss was calculated based on the average data of surface temperature. The results indicated that the young broilers fed the high-energy diet presented a metabolic energy loss equivalent to 0.64 kcal h-1, while the birds fed with the control diet lost 2.18 kcal h-1. This finding confirms that oil supplementation to the diet reduces bird heat loss. The infrared camera was able to record young broilers' surface temperature variation when birds were fed diets with different energy contents.

  20. Evaluating Non-Aromatic Rice Varieties for Growth and Yield under Different Rates of Soil Applied Boron

    Directory of Open Access Journals (Sweden)

    Javaid Ahmed Shah

    2016-05-01

    Full Text Available Balanced boron (B fertilization has prime importance to obtain maximum paddy yield. The range between B deficiency and toxicity is smaller than most plant nutrients, though B requirement among different crops varies widely. The adequate dose of B for one genotype can either be insufficient or toxic to other. Hence, without knowing the actual requirements of crop varieties, B application can be risky due to the toxicity hazards. A field experiment was undertaken at experimental farm of Nuclear Institute of Agriculture (NIA Tandojam during 2013, to evaluate the B requirement of two non-aromatic rice varieties. The experiment was arranged in split plot design with three repeats. Two rice varieties Sarshar and Shandar were grown in main plots with four rates of B: 0.5, 1.0, 1.5 and 2.0 kg ha-1 and control (0 kg ha-1 in sub plots. Both the varieties responded differently to B rates. Sarshar produced the highest paddy yield (5691 kg ha-1 at a rate of 1.5 kg B ha-1 and was 18% greater than control, Shandar produced the highest yield (6075 kg ha-1 at a rate of 1.0 kg B ha-1and was 5% greater than control. B accumulation in paddy and straw of both varieties increased with the increasing B rates. Both varieties were also significantly (p<0.05 varied in B accumulations. Comparatively, rice variety Sarshar accumulated 9% and 22% more B in straw and paddy than the Shandar. Thus, the B requirement of Sarshar was relatively higher than the Shandar. Shandar can be grown without the additional B application, whereas, Sarshar requires additional B for its maximum harvest in B deficient soils.

  1. Prediction of Pollution Flashover Voltage Based on Leakage Current Under AC Operating Voltage

    Institute of Scientific and Technical Information of China (English)

    MEI Hongwei; WANG Liming; GUAN Zhicheng; MAO Yingke

    2012-01-01

    This paper presented a model to predict the AC flashover voltage of contaminated suspension insulators.The prediction method is based on the maximum leakage current under AC operating voltage.Three kinds of widely used suspension insulators were tested in various contamination states such as pollution layers with different equivalent salt deposit density(ESDD),different composition of the conductive components,different non-soluble deposit density(NSDD) and different pollution distribution states to simulate the contamination states in nature.The effective ESDD was proposed and calculated.Influences of contamination states to maximum leakage current and flashover voltage were studied.Then,the relationships between flashover voltage and leakage current in these states were presented.Finally,considering the difference of insulator profiles,a new parameter is defined and a model to estimate the flashover voltage based on this parameter is developed.The model could be used in all kinds of suspension insulators in different contamination states and was validated by the test results.

  2. High voltage pulse generator. [Patent application

    Science.gov (United States)

    Fasching, G.E.

    1975-06-12

    An improved high-voltage pulse generator is described which is especially useful in ultrasonic testing of rock core samples. An N number of capacitors are charged in parallel to V volts and at the proper instance are coupled in series to produce a high-voltage pulse of N times V volts. Rapid switching of the capacitors from the paralleled charging configuration to the series discharging configuration is accomplished by using silicon-controlled rectifiers which are chain self-triggered following the initial triggering of the first rectifier connected between the first and second capacitors. A timing and triggering circuit is provided to properly synchronize triggering pulses to the first SCR at a time when the charging voltage is not being applied to the parallel-connected charging capacitors. The output voltage can be readily increased by adding additional charging networks. The circuit allows the peak level of the output to be easily varied over a wide range by using a variable autotransformer in the charging circuit.

  3. Voltage stability, bifurcation parameters and continuation methods

    Energy Technology Data Exchange (ETDEWEB)

    Alvarado, F.L. [Wisconsin Univ., Madison, WI (United States)

    1994-12-31

    This paper considers the importance of the choice of bifurcation parameter in the determination of the voltage stability limit and the maximum power load ability of a system. When the bifurcation parameter is power demand, the two limits are equivalent. However, when other types of load models and bifurcation parameters are considered, the two concepts differ. The continuation method is considered as a method for determination of voltage stability margins. Three variants of the continuation method are described: the continuation parameter is the bifurcation parameter the continuation parameter is initially the bifurcation parameter, but is free to change, and the continuation parameter is a new `arc length` parameter. Implementations of voltage stability software using continuation methods are described. (author) 23 refs., 9 figs.

  4. Applying an Inverse Model to Estimate Ammonia Emissions at Cattle Feedlots Using Three Different Observation-Based Approaches

    Science.gov (United States)

    Shonkwiler, K. B.; Ham, J. M.; Nash, C.

    2014-12-01

    Accurately quantifying emissions of ammonia (NH3) from confined animal feeding operations (CAFOs) is vital not only to the livestock industry, but essential to understanding nitrogen cycling along the Front Range of Colorado, USA, where intensive agriculture, urban sprawl, and pristine ecosystems (e.g., Rocky Mtn Nat'l Park) lie within 100-km of each other. Most observation-based techniques for estimating NH3 emissions can be expensive and highly technical. Many methods rely on concentration observations on location, which implicitly depends on weather conditions. A system for sampling NH3 using on-site weather data was developed to allow remote measurement of NH3 in a simple, cost-effective way. These systems use passive diffusive cartridges (Radiello, Sigma-Aldrich) that provide time-averaged concentrations representative of a typical two-week deployment. Cartridge exposure is robotically managed so they are only visible when winds are 1.4 m/s or greater from the direction of the CAFO. These concentration data can be coupled with stability parameters (measured on-site) in a simple inverse model to estimate emissions (FIDES, UMR Environnement et Grandes Cultures). Few studies have directly compared emissions estimates of NH3 using concentration data obtained from multiple measurement systems at different temporal and spatial scales. Therefore, in the summer and autumn of 2014, several conditional sampler systems were deployed at a 25,000-head cattle feedlot concomitant with an open-path infrared laser (GasFinder2, Boreal Laser Inc.) and a Cavity Ring Down Spectrometer (CRDS) (G1103, Picarro Inc.) which each measured instantaneous NH3 concentrations. This study will test the sampler technology by first comparing concentration data from the three different methods. In livestock research, it is common to estimate NH3 emissions by using such instantaneous data in a backward Lagrangian stochastic (bLs) model (WindTrax, Thunder Beach Sci.) Considering this, NH3 fluxes

  5. WAVELET BASED CLASSIFICATION OF VOLTAGE SAG, SWELL & TRANSIENTS

    Directory of Open Access Journals (Sweden)

    Vijay Gajanan Neve

    2013-05-01

    Full Text Available When the time localization of the spectral components is needed, the WAVELE TRANSFORM (WT can be used to obtain the optimal time frequency representation of the signal. This paper deals with the use of a wavelet transform to detect and analyze voltage sags, voltage swell and transients. It introduces voltage disturbance detection approach based on wavelet transform, identifies voltage disturbances, and discriminates the type of event which has resulted in the voltage disturbance, e.g. either a fault or a capacitor-switching incident.Feasibility of the proposed disturbance detection approach is demonstrated based on digital time-domain simulation of a distribution power system using the PSCAD software package, and is implemented using MATLAB. The developed algorithm has been applied to the 14-buses IEEE system to illustrate its application. Results are analyzed.

  6. Breakdown voltage of metal-oxide resistors in liquid argon

    Energy Technology Data Exchange (ETDEWEB)

    Bagby, L. F. [Fermilab; Gollapinni, S. [Kansas State U.; James, C. C. [Fermilab; Jones, B. J.P. [MIT; Jostlein, H. [Fermilab; Lockwitz, S. [Fermilab; Naples, D. [Pittsburgh U.; Raaf, J. L. [Fermilab; Rameika, R. [Fermilab; Schukraft, A. [Fermilab; Strauss, T. [Bern U., LHEP; Weber, M. S. [Bern U., LHEP; Wolbers, S. A. [Fermilab

    2014-11-07

    We characterized a sample of metal-oxide resistors and measured their breakdown voltage in liquid argon by applying high voltage (HV) pulses over a 3 second period. This test mimics the situation in a HV-divider chain when a breakdown occurs and the voltage across resistors rapidly rise from the static value to much higher values. All resistors had higher breakdown voltages in liquid argon than their vendor ratings in air at room temperature. Failure modes range from full destruction to coating damage. In cases where breakdown was not catastrophic, subsequent breakdown voltages were lower in subsequent measuring runs. One resistor type withstands 131 kV pulses, the limit of the test setup.

  7. On-Line Voltage Stability Assessment based on PMU Measurements

    DEFF Research Database (Denmark)

    Garcia-Valle, Rodrigo; P. Da Silva, Luiz C.; Nielsen, Arne Hejde

    2009-01-01

    through statistic analysis. During the off-line analysis, a memory of high-risk situations following a pre-defined voltage stability criterion is obtained. Thereafter, basic statistics analyses are applied resulting in the definition of voltage regions. During on-line operation, voltage magnitudes......This paper presents a method for on-line monitoring of risk voltage collapse based on synchronised phasor measurement. As there is no room for intensive computation and analysis in real-time, the method is based on the combination of off-line computation and on-line monitoring, which are correlated...... of critical buses obtained by phasor measurements are monitored in relation to the risk regions. Comprehensive studies demonstrate that the proposed method could assist operators to avoid voltage collapse events, by taking preventive or emergency actions....

  8. 淀粉在含乳甜点中的应用%Research of Different Starches Applying in Dairy Dessert

    Institute of Scientific and Technical Information of China (English)

    Daniel Tse

    2002-01-01

    The trials compared the performance of traditional native starch, one traditional modified starch and 2 functional native starches (NOVATION 2600 and NOVATION 3300) in dairy desserts.The trials focused on the functional characteristics of the different starches in dairy desserts,examining product quality in terms of sensory perception, texture analysis, shelf life stability and flow viscosity profile.Both NOVATION 2600 and 3300 showed performance equal to the modified starch, giving stability and a creamy texture to a dairy dessert. Both sensory and instrumentation tests demonstrated that these functional native starches compared well to the modified starches, whereas traditional native starches could not match the required performance.%本文通过普通淀粉、某变性淀粉和两种功能性天然淀粉Novation 2600和Novation3300在乳制甜点中的应用实验,从产品的货架期、结构、口感以及粘度等方面对不同淀粉的功能特性进行了比较.口感测试和仪器测试结果均可证明,两种功能性天然淀粉与该变性淀粉相似,赋予甜点稳定性和奶油感.而普通淀粉则无此贡献.

  9. Topology, divergence dates, and macroevolutionary inferences vary between different tip-dating approaches applied to fossil theropods (Dinosauria).

    Science.gov (United States)

    Bapst, D W; Wright, A M; Matzke, N J; Lloyd, G T

    2016-07-01

    Dated phylogenies of fossil taxa allow palaeobiologists to estimate the timing of major divergences and placement of extinct lineages, and to test macroevolutionary hypotheses. Recently developed Bayesian 'tip-dating' methods simultaneously infer and date the branching relationships among fossil taxa, and infer putative ancestral relationships. Using a previously published dataset for extinct theropod dinosaurs, we contrast the dated relationships inferred by several tip-dating approaches and evaluate potential downstream effects on phylogenetic comparative methods. We also compare tip-dating analyses to maximum-parsimony trees time-scaled via alternative a posteriori approaches including via the probabilistic cal3 method. Among tip-dating analyses, we find opposing but strongly supported relationships, despite similarity in inferred ancestors. Overall, tip-dating methods infer divergence dates often millions (or tens of millions) of years older than the earliest stratigraphic appearance of that clade. Model-comparison analyses of the pattern of body-size evolution found that the support for evolutionary mode can vary across and between tree samples from cal3 and tip-dating approaches. These differences suggest that model and software choice in dating analyses can have a substantial impact on the dated phylogenies obtained and broader evolutionary inferences.

  10. Turbulence statistics applied to calculate expected turbulence-induced scintillation effects on electro-optical systems in different climatic regions

    Science.gov (United States)

    Weiss-Wrana, Karin R.

    2005-08-01

    The refractive-index structure parameter Cn2 is the parameter most commonly used to describe the optically active turbulence. In the past, FGAN-FOM carried out long-term experiments in moderate climate (Central Europe, Germany), arid (summer), and semiarid (winter) climate (Middle East, Israel). Since Cn2 usually changes as a function of time of day and of season its influence on electro-optical systems should be expressed in a statistical way. We composed a statistical data base of Cn2 values. The cumulative frequency of occurrence was calculated for a time interval of two hours around noon (time of strongest turbulence), at night, and around sunrise (time of weakest turbulence) for an arbitrarily selected period of one month in summer and in winter. In October 2004 we extended our long-term turbulence experiments to subarctic climate (North Europe, Norway). First results of our turbulence measurement over snow-covered terrain indicate Cn2 values which are similar or even higher than measured values in Central European winter. The statistical data base was used to calculate the expected turbulence-induced aperture-averaged scintillation index for free-space optical systems (FSO system) in different climates. The calculations were performed for commercially available FSO systems with wavelength of 785 nm and 1.55 µm respectively and with aperture diameters of the receiver of 60 mm and 150 mm for horizontal path at two heights, 2.3 m and 10 m above ground.

  11. Cathodic bacterial community structure applying the different co-substrates for reductive decolorization of Alizarin Yellow R.

    Science.gov (United States)

    Sun, Qian; Li, Zhi-Ling; Wang, You-Zhao; Yang, Chun-Xue; Chung, Jong Shik; Wang, Ai-Jie

    2016-05-01

    Selective enrichment of cathodic bacterial community was investigated during reductive decolorization of AYR fedding with glucose or acetate as co-substrates in biocathode. A clear distinction of phylotype structures were observed between glucose-fed and acetate-fed biocathodes. In glucose-fed biocathode, Citrobacter (29.2%), Enterococcus (14.7%) and Alkaliflexus (9.2%) were predominant, and while, in acetate-fed biocathode, Acinetobacter (17.8%) and Achromobacter (6.4%) were dominant. Some electroactive or reductive decolorization genera, like Pseudomonas, Delftia and Dechloromonas were commonly enriched. Both of the higher AYR decolorization rate (k(AYR)=0.46) and p-phenylenediamine (PPD) generation rate (k(PPD)=0.38) were obtained fed with glucose than acetate (k(AYR)=0.18; k(PPD)=0.16). The electrochemical behavior analysis represented a total resistance in glucose-fed condition was about 73.2% lower than acetate-fed condition. The different co-substrate types, resulted in alteration of structure, richness and composition of bacterial communities, which significantly impacted the performances and electrochemical behaviors during reductive decolorization of azo dyes in biocathode.

  12. Performances and Coating Morphology of a Siloxane-Based Hydrophobic Product Applied in Different Concentrations on a Highly Porous Stone

    Directory of Open Access Journals (Sweden)

    Mariateresa Lettieri

    2016-11-01

    Full Text Available Many polymers, able to confer a hydrophobicity to treated surfaces, have been proposed for the restoration and conservation of civil and monumental buildings. Polysiloxanes, and their precursors, the silanes, have been frequently employed for stone protection. To avoid decay of the treated surfaces, the effectiveness and harmlessness of the treatment need to be carefully evaluated before application in the field. In this study, a commercial alkyl-siloxane was tested as a protective treatment on a highly porous stone, starting from water solutions with different contents of the product. The treatments have been devised to try to balance the requirements and the sustainability of the conservative actions. Sustainability, in terms of costs and environmental impact, is regarded as a key factor in the 21st century. Morphological observations of the stone surface, static contact angle and colour measurements, water vapour transmission test, and tests of water absorption were carried out to characterize the untreated and treated stones. A concentration below the minimum level suggested by the manufacturer was still able to act as a good barrier against water. More concentrated solutions produced polymer accumulation and coatings with extended cracks. The properties of the treated stone were affected by the presence of cracks in the coating.

  13. Offset Correction Techniques for Voltage Sense Amplifiers

    NARCIS (Netherlands)

    Groeneveld, S.

    2006-01-01

    This report deals with offset correction techniques for voltage sense amplifiers and is divided into two different parts: 1) mismatch and 2) offset correction techniques. First a literature study is done on the subject mismatch with specially focus on the future. Mismatch of a transistor is determin

  14. Determination of threshold and maximum operating electric stresses for selected high voltage insulation. Task 3: Investigation of high voltage capacitor insulation

    Science.gov (United States)

    Sosnowski, M.; Eager, G. S., Jr.

    1984-03-01

    The threshold voltage of capacitor insulation was investigated. The experimental work was performed on samples prepared from commercial polypropylene insulated, liquid-filled capacitors. The samples were vacuum-impregnated with the original capacitor insulating liquid obtained from the manufacturer. A limited number of full-size capacitor elements also were tested. Impulse voltage breakdown tests with dc voltage prestressing were performed at room temperature and 75 C. From the results of these tests, the threshold voltage of the samples of the capacitor insulation was determined at both temperatures and that of the whole capacitor elements at room temperature. The threshold voltage of the capacitor insulation was found to be approximately equal to the impulse breakdown voltage. No difference was found between the threshold voltage at room temperature and at 75 C. The threshold voltage of the whole capacitor elements at room temperature was found to be equal to approximately 80% of the threshold voltage of the capacitor insulation samples.

  15. Voltage Dependence of Supercapacitor Capacitance

    Directory of Open Access Journals (Sweden)

    Szewczyk Arkadiusz

    2016-09-01

    Full Text Available Electronic Double-Layer Capacitors (EDLC, called Supercapacitors (SC, are electronic devices that are capable to store a relatively high amount of energy in a small volume comparing to other types of capacitors. They are composed of an activated carbon layer and electrolyte solution. The charge is stored on electrodes, forming the Helmholtz layer, and in electrolyte. The capacitance of supercapacitor is voltage- dependent. We propose an experimental method, based on monitoring of charging and discharging a supercapacitor, which enables to evaluate the charge in an SC structure as well as the Capacitance-Voltage (C-V dependence. The measurement setup, method and experimental results of charging/discharging commercially available supercapacitors in various voltage and current conditions are presented. The total charge stored in an SC structure is proportional to the square of voltage at SC electrodes while the charge on electrodes increases linearly with the voltage on SC electrodes. The Helmholtz capacitance increases linearly with the voltage bias while a sublinear increase of total capacitance was found. The voltage on SC increases after the discharge of electrodes due to diffusion of charges from the electrolyte to the electrodes. We have found that the recovery voltage value is linearly proportional to the initial bias voltage value.

  16. Performance evaluation of different solar advanced oxidation processes applied to the treatment of a real textile dyeing wastewater.

    Science.gov (United States)

    Manenti, Diego R; Soares, Petrick A; Silva, Tânia F C V; Módenes, Aparecido N; Espinoza-Quiñones, Fernando R; Bergamasco, Rosângela; Boaventura, Rui A R; Vilar, Vítor J P

    2015-01-01

    The performance of different solar-driven advanced oxidation processes (AOPs), such as TiO2/UV, TiO2/H2O2/UV, and Fe(2+)/H2O2/UV-visible in the treatment of a real textile effluent using a pilot plant with compound parabolic collectors (CPCs), was investigated. The influence of the main photo-Fenton reaction variables such as iron concentration (20-100 mg Fe(2+) L(-1)), pH (2.4-4.5), temperature (10-50 °C), and irradiance (22-68 WUV m(-2)) was evaluated in a lab-scale prototype using artificial solar radiation. The real textile wastewater presented a beige color, with a maximum absorbance peak at 641 nm, alkaline pH (8.1), moderate organic content (dissolved organic carbon (DOC) = 129 mg C L(-1) and chemical oxygen demand (COD) = 496 mg O2 L(-1)), and high conductivity mainly associated to the high concentration of chloride (1.1 g Cl(-) L(-1)), sulfate (0.4 g SO 4 (2 -) L(- 1)), and sodium (1.2 g Na(+) L(-1)) ions. Although all the processes tested contributed to complete decolorization and effective mineralization, the most efficient process was the solar photo-Fenton with an optimum catalyst concentration of 60 mg Fe(2+) L(-1), leading to 70 % mineralization (DOCfinal = 41 mg C L(-1); CODfinal UV energy dose of 3.5 kJUV L(-1) (t 30 W = 22.4 min; [Formula: see text]; [Formula: see text]) and consuming 18.5 mM of H2O2.

  17. RCM skill assessment applying precipitation, temperature and hydrological performance measures: comparing different RCM resolutions and bias correction methods

    Science.gov (United States)

    Pasten-Zapata, Ernesto; Jones, Julie; Moggridge, Helen; Widmann, Martin

    2017-04-01

    Global Climate Models (GCMs) are the main tool to assess futures changes in climate and their impacts. Due to their coarse resolution, GCMs fail to accurately simulate observed climate variables at the catchment scale. Therefore, climate researchers have focused on increasing model resolution by nesting Regional Climate Models (RCMs) into the GCMs for regional areas, a process known as dynamical downscaling. Commonly, RCMs also have simulation biases at the catchment scale and therefore statistical techniques, known as bias correction methods, are used to reduce such biases. In this project the skill to simulate precipitation and temperature from five reanalysis-driven Euro-CORDEX RCMs is evaluated. Furthermore, RCM precipitation and temperature outputs are coupled with a hydrological model (the HEC-HMS model) to simulate river flow at the catchment scale. Precipitation, temperature and hydrological biases are assessed using a range of metrics combining mean, extremes, time series and distribution measures. In order to evaluate the dynamical downscaling effect, the RCMs are analyzed at two resolutions: 0.44° and 0.11°. Additionally, both resolutions are bias-corrected employing the parametric quantile-mapping method: a) temperature is bias-corrected using the normal distribution, and b) precipitation is bias-corrected using the gamma and double-gamma distributions. Four catchments across England and Wales covering different climate conditions and topographical characteristics are used as study sites. The results from this study provide an overview of the skill of current state-of-the-art RCMs and their suitability for hydrological impact analysis at the catchment scale. Furthermore, for precipitation the study analyses the performance of the commonly-used gamma distribution quantile-mapping bias-correction method comparing it to the double-gamma distribution method considering their implications towards the simulation of hydrological impacts.

  18. Modeling of dielectric barrier discharge excimer lamp excited by mono polar voltage pulses

    Science.gov (United States)

    Akashi, Haruaki; Oda, Akinori; Sakai, Yosuke

    2007-10-01

    Filametal discharges in Dielectric Barrier Discharge (DBD) excimer lamp excited by mono polar voltage pulses has been simulated using two dimensional fluid model. And the differences of the filament discharges formations between mono polar case and bipolar case [1] have been examined. Xe gas was used and its pressure is 300Torr. Simulated region is 1cm (gap length) x 3cm (radial length). Periodical boundary conditions are assumed for the radial direction boundaries. The both electrodes are covered with dielectrics and their thickness is 0.2cm. Applied voltage is 5kV trapezoid shape with 50% duty ratio waveform and its repetition rate is 200kpps. First a small amount of electron-ion pair is provided in the middle of the gap for initial condition. Then the voltage starts to apply. In the case of bipolar excitation, the discharge starts from one filament (streamer discharge), and finally, 5 filaments are obtained self-consistently. In the case of mono polar case, as first, similar to bipolar case, the discharge starts from one filament, however, only 3 filaments have been obtained. This result is similar to that of 100kHz bipolar voltage case. [1] H. Akashi et al, IEEE Trans. Plasma Science, Vol.33, No.2 (2005) pp.308-309

  19. Lightning-induced overvoltages in medium voltage distribution systems and customer experienced voltage spikes

    Energy Technology Data Exchange (ETDEWEB)

    Sabiha, N. A.

    2010-07-01

    accurate and simplified model is proposed concerning unloaded and loaded conditions as well. The proposed high frequency transformer model is experimentally verified under different balanced load conditions considering two different practical distribution transformers. Then the impact of low voltage (LV) network feeder numbers, lengths, types and loads on the lightning-induced overvoltage reached at the service entrance point is investigated with and without MV spark-gap operation. The high frequency model representation of the distribution transformer and low voltage network are combined in a single arrangement in the environment of ATP/EMTP. A simplified low voltage surge arrester model is represented and verified. Finally, a study is carried out to mitigate the overvoltages by allocating the surge arrester at secondary side of the distribution transformer with concerning MV spark-gap operation. (orig.)

  20. Voltage-Induced Effect on Resistance of C:N/Si Heterojunctions

    Institute of Scientific and Technical Information of China (English)

    GAO Xi-Li; ZHANG Xiao-Zhong; WAN Cai-Hua; WANG Ji-Min

    2012-01-01

    Nitrogen doped a-C/Silicon (a-C:N/Si) heterojunctions have been fabricated by using the pulsed laser deposition (PLD) technique and their current-voltage characteristics at various temperatures are investigated.For reverse applied voltages,a-C:N/Si heterojunctions exhibit metal-insulator transition characteristics and the transition temperature can be controlled by the applied voltages.After the excitation of repeated high reverse applied voltages,the current-voltage curves show obvious hysteresis behaviors at low temperatures.These hysteresis behaviors are reproducible and the ratio of the high/low resistance can be greater than 104.%Nitrogen doped a-C/Silicon (a-C:N/Si) heterojunctions have been fabricated by using the pulsed laser deposition (PLD) technique and their current-voltage characteristics at various temperatures are investigated. For reverse applied voltages, a-C.N/Si heterojunctions exhibit metal-insulator transition characteristics and the transition temperature can be controlled by the applied voltages. After the excitation of repeated high reverse applied voltages, the current-voltage curves show obvious hysteresis behaviors at low temperatures. These hysteresis behaviors are reproducible and the ratio of the high/low resistance can be greater than 104.

  1. Simple device to determine the pressure applied by pressure clips for the treatment of earlobe keloids

    Directory of Open Access Journals (Sweden)

    Aashish Sasidharan

    2015-01-01

    Full Text Available Background: Keloids of the ear are common problems. Various treatment modalities are available for the treatment of ear keloids. Surgical excision with intralesional steroid injection along with compression therapy has the least recurrence rate. Various types of devices are available for pressure therapy. Pressure applied by these devices is uncontrolled and is associated with the risk of pressure necrosis. We describe here a simple and easy to use device to measure pressure applied by these clips for better outcome. Objectives: To devise a simple method to measure the pressure applied by various pressure clips used in ear keloid pressure therapy. Materials and Methods: By using a force sensitive resistor (FSR, the pressure applied gets converted into voltage using electrical wires, resistors, capacitors, converter, amplifier, diode, nine-volt (9V cadmium battery and the voltage is measured using a multimeter. The measured voltage is then converted into pressure using pressure voltage graph that depicts the actual pressure applied by the pressure clip. Results: The pressure applied by different clips was variable. The spring clips were adjustable by slight variation in the design whereas the pressure applied by binder clips and magnet discs was not adjustable. Conclusion: The uncontrolled/suboptimal pressure applied by certain pressure clips can be monitored to provide optimal pressure therapy in ear keloid for better outcome.

  2. Porous and mesh alumina formed by anodization of high purity aluminum films at low anodizing voltage

    Energy Technology Data Exchange (ETDEWEB)

    Abd-Elnaiem, Alaa M., E-mail: alaa.abd-elnaiem@science.au.edu.eg [KACST-Intel Consortium Center of Excellence in Nano-manufacturing Applications (CENA), Riyadh (Saudi Arabia); Physics Department, Faculty of Science, Assiut University, Assiut 71516 (Egypt); Mebed, A.M. [Physics Department, Faculty of Science, Assiut University, Assiut 71516 (Egypt); Department of Physics, Faculty of Science, Al-Jouf University, Sakaka 2014 (Saudi Arabia); El-Said, Waleed Ahmed [Department of Chemistry, Faculty of Science, Assiut University, Assiut 71516 (Egypt); Abdel-Rahim, M.A. [Physics Department, Faculty of Science, Assiut University, Assiut 71516 (Egypt)

    2014-11-03

    Electrochemical oxidation of high-purity aluminum (Al) films under low anodizing voltages (1–10) V has been conducted to obtain anodic aluminum oxide (AAO) with ultra-small pore size and inter-pore distance. Different structures of AAO have been obtained e.g. nanoporous and mesh structures. Highly regular pore arrays with small pore size and inter-pore distance have been formed in oxalic or sulfuric acids at different temperatures (22–50 °C). It is found that the pore diameter, inter-pore distance and the barrier layer thickness are independent of the anodizing parameters, which is very different from the rules of general AAO fabrication. The brand formation mechanism has been revealed by the scanning electron microscope study. Regular nanopores are formed under 10 V at the beginning of the anodization and then serve as a template layer dominating the formation of ultra-small nanopores. Anodization that is performed at voltages less than 5 V leads to mesh structured alumina. In addition, we have introduced a simple one-pot synthesis method to develop thin walls of oxide containing lithium (Li) ions that could be used for battery application based on anodization of Al films in a supersaturated mixture of lithium phosphate and phosphoric acid as matrix for Li-composite electrolyte. - Highlights: • We develop anodic aluminum oxide (AAO) with small pore size and inter-pore distance. • Applying low anodizing voltages onto aluminum film leads to form mesh structures. • The value of anodizing voltage (1–10 V) has no effect on pore size or inter-pore distance. • Applying anodizing voltage less than 5 V leads to mesh structured AAO. • AAO can be used as a matrix for Li-composite electrolytes.

  3. Voltage-sensitive rhodol with enhanced two-photon brightness.

    Science.gov (United States)

    Kulkarni, Rishikesh U; Kramer, Daniel J; Pourmandi, Narges; Karbasi, Kaveh; Bateup, Helen S; Miller, Evan W

    2017-03-14

    We have designed, synthesized, and applied a rhodol-based chromophore to a molecular wire-based platform for voltage sensing to achieve fast, sensitive, and bright voltage sensing using two-photon (2P) illumination. Rhodol VoltageFluor-5 (RVF5) is a voltage-sensitive dye with improved 2P cross-section for use in thick tissue or brain samples. RVF5 features a dichlororhodol core with pyrrolidyl substitution at the nitrogen center. In mammalian cells under one-photon (1P) illumination, RVF5 demonstrates high voltage sensitivity (28% ΔF/F per 100 mV) and improved photostability relative to first-generation voltage sensors. This photostability enables multisite optical recordings from neurons lacking tuberous sclerosis complex 1, Tsc1, in a mouse model of genetic epilepsy. Using RVF5, we show that Tsc1 KO neurons exhibit increased activity relative to wild-type neurons and additionally show that the proportion of active neurons in the network increases with the loss of Tsc1. The high photostability and voltage sensitivity of RVF5 is recapitulated under 2P illumination. Finally, the ability to chemically tune the 2P absorption profile through the use of rhodol scaffolds affords the unique opportunity to image neuronal voltage changes in acutely prepared mouse brain slices using 2P illumination. Stimulation of the mouse hippocampus evoked spiking activity that was readily discerned with bath-applied RVF5, demonstrating the utility of RVF5 and molecular wire-based voltage sensors with 2P-optimized fluorophores for imaging voltage in intact brain tissue.

  4. Assessment of image quality and low-contrast detectability in abdominal CT of obese patients: comparison of a novel integrated circuit with a conventional discrete circuit detector at different tube voltages

    Energy Technology Data Exchange (ETDEWEB)

    Euler, A.; Heye, T.; Kekelidze, M.; Bongartz, G.; Schindera, Sebastian T. [University of Basel Hospital, Clinic of Radiology and Nuclear Medicine, Basel (Switzerland); Szucs-Farkas, Z. [Hospital Centre of Biel, Institute of Radiology, Biel (Switzerland); Sommer, C. [University Hospital, Department of Diagnostic and Interventional Radiology, Heidelberg (Germany); Schmidt, B. [Siemens Healthcare Sector, Forchheim (Germany)

    2014-10-15

    To compare image quality and low-contrast detectability of an integrated circuit (IC) detector in abdominal CT of obese patients with conventional detector technology at low tube voltages. A liver phantom with 45 lesions was placed in a water container to mimic an obese patient and examined on two different CT systems at 80, 100 and 120 kVp. The systems were equipped with either the IC or conventional detector. Image noise was measured, and the contrast-to-noise-ratio (CNR) was calculated. Low-contrast detectability was assessed independently by three radiologists. Radiation dose was estimated by the volume CT dose index (CTDI{sub vol}). The image noise was significantly lower, and the CNR was significantly higher with the IC detector at 80, 100 and 120 kVp, respectively (P = 0.023). The IC detector resulted in an increased lesion detection rate at 80 kVp (38.1 % vs. 17.2 %) and 100 kVp (57.0 % vs. 41.0 %). There was no difference in the detection rate between the IC detector at 100 kVp and the conventional detector at 120 kVp (57.0 % vs. 62.2 %). The CTDI{sub vol} at 80, 100 and 120 kVp measured 4.5-5.2, 7.3-7.9 and 9.8-10.2 mGy, respectively. The IC detector at 100 kVp resulted in similar low-contrast detectability compared to the conventional detector with a 120-kVp protocol at a radiation dose reduction of 37 %. (orig.)

  5. Applied dynamics

    CERN Document Server

    Schiehlen, Werner

    2014-01-01

    Applied Dynamics is an important branch of engineering mechanics widely applied to mechanical and automotive engineering, aerospace and biomechanics as well as control engineering and mechatronics. The computational methods presented are based on common fundamentals. For this purpose analytical mechanics turns out to be very useful where D’Alembert’s principle in the Lagrangian formulation proves to be most efficient. The method of multibody systems, finite element systems and continuous systems are treated consistently. Thus, students get a much better understanding of dynamical phenomena, and engineers in design and development departments using computer codes may check the results more easily by choosing models of different complexity for vibration and stress analysis.

  6. Treatment of emulsified oils by electrocoagulation: pulsed voltage applications.

    Science.gov (United States)

    Genc, Ayten; Bakirci, Busra

    2015-01-01

    The effect of pulsed voltage application on energy consumption during electrocoagulation was investigated. Three voltage profiles having the same arithmetic average with respect to time were applied to the electrodes. The specific energy consumption for these profiles were evaluated and analyzed together with oil removal efficiencies. The effects of applied voltages, electrode materials, electrode configurations, and pH on oil removal efficiency were determined. Electrocoagulation experiments were performed by using synthetic and real wastewater samples. The pulsed voltages saved energy during the electrocoagulation process. In continuous operation, energy saving was as high as 48%. Aluminum electrodes used for the treatment of emulsified oils resulted in higher oil removal efficiencies in comparison with stainless steel and iron electrodes. When the electrodes gap was less than 1 cm, higher oil removal efficiencies were obtained. The highest oil removal efficiencies were 95% and 35% for the batch and continuous operating modes, respectively.

  7. Voltage Balancing Method on Expert System for 51-Level MMC in High Voltage Direct Current Transmission

    Directory of Open Access Journals (Sweden)

    Yong Chen

    2016-01-01

    Full Text Available The Modular Multilevel Converters (MMC have been a spotlight for the high voltage and high power transmission systems. In the VSC-HVDC (High Voltage Direct Current based on Voltage Source Converter transmission system, the energy of DC link is stored in the distributed capacitors, and the difference of capacitors in parameters and charge rates causes capacitor voltage balance which affects the safety and stability of HVDC system. A method of MMC based on the expert system for reducing the frequency of the submodules (SMs of the IGBT switching frequency is proposed. Firstly, MMC with 51 levels for HVDC is designed. Secondly, the nearest level control (NLC for 51-level MMC is introduced. Thirdly, a modified capacitor voltage balancing method based on expert system for MMC-based HVDC transmission system is proposed. Finally, a simulation platform for 51-level Modular Multilevel Converter is constructed by using MATLAB/SIMULINK. The results indicate that the strategy proposed reduces the switching frequency on the premise of keeping submodule voltage basically identical, which greatly reduces the power losses for MMC-HVDC system.

  8. Voltage on the distribution of the residual chlorine ion of the concrete after the electrochemical dechlorination treatment

    Science.gov (United States)

    Zhang, Kun; Shan, Wei; Sun, Wen-bo

    2017-04-01

    This paper utilizes 60V stable voltage power, saturated calcium hydroxide solution, titanium mesh anode to analyze the influence of the mineral admixtures, applied voltage and electrolyte solution on the residual chloride ions distribution after 14 consecutive days’ test of the electrochemical chloride extraction of the cylinder concrete. The results show that after electrochemical chloride extraction, the residual chloride ions content in concrete shows increasing trend from inside to outside of the reinforced interface, with the least at internal layer and the most at external layer and there are 2-3.5 times differences between internal layer and external layer. The difference between the internal layer and external layer increases with the increase of the chloride extraction voltage.

  9. Voltage-induced reduction of graphene oxide

    Science.gov (United States)

    Faucett, Austin C.

    Graphene Oxide (GO) is being widely researched as a precursor for the mass production of graphene, and as a versatile material in its own right for flexible electronics, chemical sensors, and energy harvesting applications. Reduction of GO, an electrically insulating material, into reduced graphene oxide (rGO) restores electrical conductivity via removal of oxygen-containing functional groups. Here, a reduction method using an applied electrical bias, known as voltage-induced reduction, is explored. Voltage-induced reduction can be performed under ambient conditions and avoids the use of hazardous chemicals or high temperatures common with standard methods, but little is known about the reduction mechanisms and the quality of rGO produced with this method. This work performs extensive structural and electrical characterization of voltage-reduced GO (V-rGO) and shows that it is competitive with standard methods. Beyond its potential use as a facile and eco-friendly processing approach, V-rGO reduction also offers record high-resolution patterning capabilities. In this work, the spatial resolution limits of voltage-induced reduction, performed using a conductive atomic force microscope probe, are explored. It is shown that arbitrary V-rGO conductive features can be patterned into insulating GO with nanoscale resolution. The localization of voltage-induced reduction to length scales < 10 nm allows studies of reduction reaction kinetics, using electrical current obtained in-situ, with statistical robustness. Methods for patterning V-rGO nanoribbons are then developed. After presenting sub-10nm patterning of V-rGO nanoribbons in GO single sheets and films, the performance of V-rGO nanoribbon field effect transistors (FETs) are demonstrated. Preliminary measurements show an increase in electrical current on/off ratios as compared to large-area rGO FETs, indicating transport gap modulation that is possibly due to quantum confinement effects.

  10. Mitigation of Voltage Swells by Static Series Compensator

    DEFF Research Database (Denmark)

    Awad, Hilmy; Blaabjerg, Frede

    2004-01-01

    is lower than a predetermined voltage level, the active power is employed to charge the ESC to this voltage level; 2) otherwise, the overvoltage protection of the SSC must operate. This paper also applies an overvoltage protection scheme based on a combination of a dc resistor with a chopper and the valves...... of the SSC. The design of the dc resistor is discussed. A 10 kV SSC experimental setup is exploited to carry out experiments in the case of balanced and unbalanced voltage swells at the grid side....

  11. Implementation of an outline of transformer induced voltage tests

    Directory of Open Access Journals (Sweden)

    Orestes Hernández Areu

    2010-02-01

    Full Text Available The results of the developed work for the implementation of the induced voltage test to be applied to single phase distribution transformers in the Researches and Electroenergetic Tests Center (CIPEL of Cuba, are presented, The test outline was obtained starting from the employment of a motor - generator group, with an external voltage regulator and using a frequency converter to obtain the necessary frequency for this type of test.

  12. Applied intelligent control of induction motor drives

    CERN Document Server

    Chan, Tze Fun

    2011-01-01

    Induction motors are the most important workhorses in industry. They are mostly used as constant-speed drives when fed from a voltage source of fixed frequency. Advent of advanced power electronic converters and powerful digital signal processors, however, has made possible the development of high performance, adjustable speed AC motor drives.This book aims to explore new areas of induction motor control based on artificial intelligence (AI) techniques in order to make the controller less sensitive to parameter changes. Selected AI techniques are applied for different induction motor control s.

  13. Differences in tensile adhesion strength between HEMA and nonHEMA-based dentin bonding applied on superficial and deep dentin surfaces

    Directory of Open Access Journals (Sweden)

    Eresha Melati Kusuma Wurdani

    2017-03-01

    Full Text Available Background: Improvement in dentistry shows some progresses, due to patients awareness on the importance of dental care. Cervical lesion is the most common phenomenon which oftenly found 46.36% in man and 38.13% in woman. Cervical lesions need composite restoration for treatment to stop the process of tissue damage. The process of adhesion of composite restoration material to the structure of the tooth is not easily separated and it needs optimal function in the oral cavity. Application of dentin bonding agents to attach the composite is needed. Selection of HEMA-based bonding material and Hema free-based bonding material which have a different solvent in their composition, as applied to the dentin superficial and deep dentin, affect the results of debonding test. Debonding test is done to measure the adhesion strength of a bonding material. Purpose: The purpose of this study was to analyze differences in tensile bond strength of dentine bonding HEMA-based and HEMA-free based after application in superficial and deep dentine surfaces. Method: The tooth of the bovine was as samples. A superficial dentine sample was taken from 0.5-1 mm of dentino enamel junction and a deep dentine sample was taken from 0.5 mm culmination of pulp horn. Dentine surface area was equal to p x r2 = (3.14 x 22 = 12.56 mm2. Six samples of HEMA-based bonding was applied to the dentine superficial. Six samples of HEMAfree based bonding was applied to the superficial dentine. Six samples of HEMA-based bonding was applied to the deep dentine. Six samples of HEMA-free based bonding was applied to the deep dentine. Tensile strength was measured using an Autograph AG-10TE. Result: There were differences tensile bond strength of dentine bonding HEMA-based and HEMA-free based after the application on superficial (p=0.000 and deep dentine surfaces (p=0.000. Conclusion: There were differences tensile bond strength of dentine bonding HEMA-based and HEMA-free based after the

  14. Long Lifetime DC-Link Voltage Stabilization Module for Smart Grid Application

    DEFF Research Database (Denmark)

    Wang, Huai; Chung, Henry; Liu, Wenchao

    2012-01-01

    Power converters enable efficient and flexible control and conversion of electric energy among different smart grid players (i.e. producers, energy storage systems, and loads). One of the expected features of smart grid is that it will be more reliable compared to conventional grid. However, power...... converters are one kind of the lifetime limiting components applied in smart grid. One of the major causes is the malfunction of electrolytic capacitors (E-Caps) which are widely used for stabilizing the dc-link voltage in various types of power converters applied in smart grid. A dc-link module is therefore...

  15. Comparative analysis of the bacterial diversity in a lab-scale moving bed biofilm reactor (MBBR) applied to treat urban wastewater under different operational conditions.

    Science.gov (United States)

    Calderón, Kadiya; Martín-Pascual, Jaime; Poyatos, José Manuel; Rodelas, Belén; González-Martínez, Alejandro; González-López, Jesús

    2012-10-01

    Different types of carriers were tested as support material in a lab-scale moving bed biofilm reactor (MBBR) used to treat urban wastewater under three different conditions of hydraulic retention time (HRT) and carrier filling ratios (FR). The bacterial diversity developed on the biofilms responsible of the treatment was studied using a cultivation-independent approach based on the polymerase chain reaction-temperature gradient gel electrophoresis technique (PCR-TGGE). Cluster analysis of TGGE fingerprints showed significant differences of community structure dependent upon the different operational conditions applied. Redundancy analysis (RDA) was used to determine the relationship between the operational conditions (type of carrier, HRT, FR) and bacterial biofilm diversity, demonstrating a significant effect of FR=50%. Phylogenetic analysis of PCR-reamplified and sequenced TGGE bands revealed that the prevalent Bacteria populations in the biofilm were related to Betaproteobacteria (46%), Firmicutes (34%),Alphaproteobacteria (14%) and Gammaproteobacteria (9%).

  16. Mechanism of electromechanical coupling in voltage-gated potassium channels

    Directory of Open Access Journals (Sweden)

    Rikard eBlunck

    2012-09-01

    Full Text Available Voltage-gated ion channels play a central role in the generation of action potentials in the nervous system. They are selective for one type of ion – sodium, calcium or potassium. Voltage-gated ion channels are composed of a central pore that allows ions to pass through the membrane and four peripheral voltage sensing domains that respond to changes in the membrane potential. Upon depolarization, voltage sensors in voltage-gated potassium channels (Kv undergo conformational changes driven by positive charges in the S4 segment and aided by pairwise electrostatic interactions with the surrounding voltage sensor. Structure-function relations of Kv channels have been investigated in detail, and the resulting models on the movement of the voltage sensors now converge to a consensus; the S4 segment undergoes a combined movement of rotation, tilt and vertical displacement in order to bring 3-4 e+ each through the electric field focused in this region. Nevertheless, the mechanism by which the voltage sensor movement leads to pore opening, the electromechanical coupling, is still not fully understood. Thus, recently, electromechanical coupling in different Kv channels has been investigated with a multitude of techniques including electrophysiology, 3D crystal structures, fluorescence spectroscopy and molecular dynamics simulations. Evidently, the S4-S5 linker, the covalent link between the voltage sensor and pore, plays a crucial role. The linker transfers the energy from the voltage sensor movement to the pore domain via an interaction with the S6 C-termini, which are pulled open during gating. In addition, other contact regions have been proposed. This review aims to provide (i an in-depth comparison of the molecular mechanisms of electromechanical coupling in different Kv channels; (ii insight as to how the voltage sensor and pore domain influence one another; and (iii theoretical predictions on the movement of the cytosolic face of the KV channels

  17. Analysis and Improvement of Reflection-type Transverse Modulation Optical Voltage Sensors

    Institute of Scientific and Technical Information of China (English)

    LUO Sunan; YE Miaoyuan; XU Yan; CUI Ying

    2001-01-01

    Reflection-type transverse modulation optical voltage sensors, which employ reflection retarders to replace quarter-wave plates, are convenient for practical use. In previous literatures, the measured voltage was all applied to Bi4Ge3O12 crystal along the (110) direction for transverse modulation optical voltage sensor, and crystals are used as sensing materials. In this paper, reflection-type transverse modulation optical voltage sensor has been analyzed theoretically and a novel configuration in which the measured voltage is applied to a Bi4C-e3O12 crystal along the (001) direction with light wave passing through the crystal in the (110) direction has been proposed. According to this theoretical analysis, a novel optical voltage sensor, which can be used in a 220 kV optical fiber voltage transformer, has been designed and assembled. Experimental results showed that the linearity and the stability of the sensor during 24 hours can reach 0.3%.

  18. Moderately nonlinear diffuse-charge dynamics under an ac voltage

    Science.gov (United States)

    Stout, Robert F.; Khair, Aditya S.

    2015-09-01

    The response of a symmetric binary electrolyte between two parallel, blocking electrodes to a moderate amplitude ac voltage is quantified. The diffuse charge dynamics are modeled via the Poisson-Nernst-Planck equations for a dilute solution of point-like ions. The solution to these equations is expressed as a Fourier series with a voltage perturbation expansion for arbitrary Debye layer thickness and ac frequency. Here, the perturbation expansion in voltage proceeds in powers of Vo/(kBT /e ) , where Vo is the amplitude of the driving voltage and kBT /e is the thermal voltage with kB as Boltzmann's constant, T as the temperature, and e as the fundamental charge. We show that the response of the electrolyte remains essentially linear in voltage amplitude at frequencies greater than the RC frequency of Debye layer charging, D /λDL , where D is the ion diffusivity, λD is the Debye layer thickness, and L is half the cell width. In contrast, nonlinear response is predicted at frequencies below the RC frequency. We find that the ion densities exhibit symmetric deviations from the (uniform) equilibrium density at even orders of the voltage amplitude. This leads to the voltage dependence of the current in the external circuit arising from the odd orders of voltage. For instance, the first nonlinear contribution to the current is O (Vo3) which contains the expected third harmonic but also a component oscillating at the applied frequency. We use this to compute a generalized impedance for moderate voltages, the first nonlinear contribution to which is quadratic in Vo. This contribution predicts a decrease in the imaginary part of the impedance at low frequency, which is due to the increase in Debye layer capacitance with increasing Vo. In contrast, the real part of the impedance increases at low frequency, due to adsorption of neutral salt from the bulk to the Debye layer.

  19. Effect of applying different rates of slow - disintegrating fertilizer on the quality of marigold (Tagetes patula L. and scarlet sage seedlings (Salvia splendens L.

    Directory of Open Access Journals (Sweden)

    Vujošević Ana

    2007-01-01

    Full Text Available The paper investigates the effect of applying different rate of slow disintegrating fertilizer Scotts (Osmocot Exact with the formula 15:9:9:MgO+Me to the quality of seedlings of marigold and scarlet sage. The marigold and scarlet sage seedlings were grown in poly-propylene containers (speedling system and poly-propylene pots (pot system. Slow disintegrating fertilizer rate have been applied to the seedlings in the course of their growing (0, 1, 2, 3, i 4 g/l. The obtained data show that the 4g/l substrate rate of slow disintegrating fertilizer has significant effects on the studied parameters of seedlings quality of studied species.

  20. Determination of appropriate DC voltage for switched mode power supply (SMPS) loads

    Science.gov (United States)

    Setiawan, Eko Adhi; Setiawan, Aiman; Purnomo, Andri; Djamal, Muchlishah Hadi

    2017-03-01

    Nowadays, most of modern and efficient household electronic devices operated based on Switched Mode Power Supply (SMPS) technology which convert AC voltage from the grid to DC voltage. Based on theory and experiment, SMPS loads could be supplied by DC voltage. However, the DC voltage rating to energize electronic home appliances is not standardized yet. This paper proposed certain method to determine appropriate DC voltage, and investigated comparison of SMPS power consumption which is supplied from AC and DC voltage. To determine the appropriate DC voltage, lux value of several lamps which have same specification energized by using AC voltage and the results is using as reference. Then, the lamps were supplied by various DC voltage to obtain the trends of the lux value to the applied DC voltage. After that, by using the trends and the reference lux value, the appropriate DC voltage can be determined. Furthermore, the power consumption on home appliances such as mobile phone, laptop and personal computer by using AC voltage and the appropriate DC voltage were conducted. The results show that the total power consumption of AC system is higher than DC system. The total power (apparent power) consumed by the lamp, mobile phone and personal computer which operated in 220 VAC were 6.93 VA, 34.31 VA and 105.85 VA respectively. On the other hand, under 277 VDC the load consumption were 5.83 W, 19.11 W and 74.46 W respectively.

  1. High voltage testing for the MAJORANA Demonstrator

    CERN Document Server

    Abgrall, N; Avignone, F T; Barabash, A S; Bertrand, F E; Bradley, A W; Brudanin, V; Busch, M; Buuck, M; Byram, D; Caldwell, A S; Chan, Y-D; Christofferson, C D; Chu, P -H; Cuesta, C; Detwiler, J A; Doe, P J; Dunagan, C; Efremenko, Yu; Ejiri, H; Elliott, S R; Fu, Z; Galindo-Uribarri, A; Giovanetti, G K; Goett, J; Green, M P; Gruszko, J; Guinn, I S; Guiseppe, V E; Henning, R; Hoppe, E W; Howard, S; Howe, M A; Jasinski, B R; Keeter, K J; Kidd, M F; Konovalov, S I; Kouzes, R T; LaFerriere, B D; Leon, J; Li, A; MacMullin, J; Martin, R D; Massarczyk, R; Meijer, S J; Mertens, S; Orrell, J L; O'Shaughnessy, C; Poon, A W P; Radford, D C; Rager, J; Rielage, K; Robertson, R G H; Romero-Romero, E; Shanks, B; Shirchenko, M; Snyder, N; Suriano, A M; Tedeschi, D; Thompson, A; Ton, K T; Trimble, J E; Varner, R L; Vasilyev, S; Vetter, K; Vorren, K; White, B R; Wilkerson, J F; Wiseman, C; Xu, W; Yakushev, E; Yu, C -H; Yumatov, V

    2016-01-01

    The MAJORANA Collaboration is constructing the MAJORANA Demonstrator, an ultra-low background, 44-kg modular high-purity Ge (HPGe) detector array to search for neutrinoless double-beta decay in Ge-76. The phenomenon of surface micro-discharge induced by high-voltage has been studied in the context of the MAJORANA Demonstrator. This eff?ect can damage the front-end electronics or mimic detector signals. To ensure the correct performance, every high-voltage cable and feedthrough must be capable of supplying HPGe detector operating voltages as high as 5 kV without exhibiting discharge. R&D measurements were carried out to understand the testing system and determine the optimum design configuration of the high-voltage path, including diff?erent improvements of the cable layout and feedthrough flange model selection. Every cable and feedthrough to be used at the MAJORANA Demonstrator was characterized and the micro-discharge eff?ects during the MAJORANA Demonstrator commissioning phase were studied. A stable c...

  2. Voltage Sensors Monitor Harmful Static

    Science.gov (United States)

    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.

  3. Voltage controlled magnetism in 3d transitional metals

    Science.gov (United States)

    Wang, Weigang

    2015-03-01

    Despite having attracted much attention in multiferroic materials and diluted magnetic semiconductors, the impact of an electric field on the magnetic properties remains largely unknown in 3d transitional ferromagnets (FMs) until recent years. A great deal of effort has been focused on the voltage-controlled magnetic anisotropy (VCMA) effect where the modulation of anisotropy field is understood by the change of electron density among different d orbitals of FMs in the presence of an electric field. Here we demonstrate another approach to alter the magnetism by electrically controlling the oxidation state of the 3d FM at the FM/oxide interface. The thin FM film sandwiched between a heavy metal layer and a gate oxide can be reversibly changed from an optimally-oxidized state with a strong perpendicular magnetic anisotropy to a metallic state with an in-plane magnetic anisotropy, or to a fully-oxidized state with nearly zero magnetization, depending on the polarity and time duration of the applied electric fields. This is a voltage controlled magnetism (VCM) effect, where both the saturation magnetization and anisotropy field of the 3d FM layer can be simultaneously controlled by voltage in a non-volatile fashion. We will also discuss the impact of this VCM effect on magnetic tunnel junctions and spin Hall switching experiments. This work, in collaboration with C. Bi, Y.H. Liu, T. Newhouse-Illige, M. Xu, M. Rosales, J.W. Freeland, O. Mryasov, S. Zhang, and S.G.E. te Velthuis, was supported in part by NSF (ECCS-1310338) and by C-SPIN, one of six centers of STARnet, a Semiconductor Research Corporation program, sponsored by MARCO and DARPA.

  4. Measurement of microchannel fluidic resistance with a standard voltage meter.

    Science.gov (United States)

    Godwin, Leah A; Deal, Kennon S; Hoepfner, Lauren D; Jackson, Louis A; Easley, Christopher J

    2013-01-03

    A simplified method for measuring the fluidic resistance (R(fluidic)) of microfluidic channels is presented, in which the electrical resistance (R(elec)) of a channel filled with a conductivity standard solution can be measured and directly correlated to R(fluidic) using a simple equation. Although a slight correction factor could be applied in this system to improve accuracy, results showed that a standard voltage meter could be used without calibration to determine R(fluidic) to within 12% error. Results accurate to within 2% were obtained when a geometric correction factor was applied using these particular channels. When compared to standard flow rate measurements, such as meniscus tracking in outlet tubing, this approach provided a more straightforward alternative and resulted in lower measurement error. The method was validated using 9 different fluidic resistance values (from ∼40 to 600kPa smm(-3)) and over 30 separately fabricated microfluidic devices. Furthermore, since the method is analogous to resistance measurements with a voltage meter in electrical circuits, dynamic R(fluidic) measurements were possible in more complex microfluidic designs. Microchannel R(elec) was shown to dynamically mimic pressure waveforms applied to a membrane in a variable microfluidic resistor. The variable resistor was then used to dynamically control aqueous-in-oil droplet sizes and spacing, providing a unique and convenient control system for droplet-generating devices. This conductivity-based method for fluidic resistance measurement is thus a useful tool for static or real-time characterization of microfluidic systems. Copyright © 2012 Elsevier B.V. All rights reserved.

  5. High Performance of Space Vector Modulation Direct Torque Control SVM-DTC Based on Amplitude Voltage and Stator Flux Angle

    Directory of Open Access Journals (Sweden)

    Hassan Farhan Rashag

    2013-04-01

    Full Text Available Various aspects related to controlling induction motor are investigated. Direct torque control is an original high performance control strategy in the field of AC drive. In this proposed method, the control system is based on Space Vector Modulation (SVM, amplitude of voltage in direct- quadrature reference frame (d-q reference and angle of stator flux. Amplitude of stator voltage is controlled by PI torque and PI flux controller. The stator flux angle is adjusted by rotor angular frequency and slip angular frequency. Then, the reference torque and the estimated torque is applied to the input of PI torque controller and the control quadrature axis voltage is determined. The control d-axis voltage is determined from the flux calculator. These q and d axis voltage are converted into amplitude voltage. By applying polar to Cartesian on amplitude voltage and stator flux angle, direct voltage and quadratures voltage are generated. The reference stator voltages in d-q are calculated based on forcing the stator voltage error to zero at next sampling period. By applying inverse park transformation on d-q voltages, the stator voltages in &alpha and &beta frame are generated and apply to SVM. From the output of SVM, the motor control signal is generated and the speed of the induction motor regulated toward the rated speed. The simulation Results have demonstrated exceptional performance in steady and transient states and shows that decrease of torque and flux ripples is achieved in a complete speed range.

  6. Capacitor voltage balance performance comparison of MMC-STATCOM using NLC and PS-PWM strategies during negative sequence current injection

    DEFF Research Database (Denmark)

    Pereira, Heverton A.; F. Cupertino, Allan; S. Xavier, Lucus

    2016-01-01

    This paper addresses the modular multilevel converter applied as a static synchronous compensator. The main objective of this work is to compare the converter performance considering two different submodule capacitor voltage balancing strategies: nearest level control and phase-shifted pulse width...

  7. Confocal Raman microscopy and multivariate statistical analysis for determination of different penetration abilities of caffeine and propylene glycol applied simultaneously in a mixture on porcine skin ex vivo.

    Science.gov (United States)

    Mujica Ascencio, Saul; Choe, ChunSik; Meinke, Martina C; Müller, Rainer H; Maksimov, George V; Wigger-Alberti, Walter; Lademann, Juergen; Darvin, Maxim E

    2016-07-01

    Propylene glycol is one of the known substances added in cosmetic formulations as a penetration enhancer. Recently, nanocrystals have been employed also to increase the skin penetration of active components. Caffeine is a component with many applications and its penetration into the epidermis is controversially discussed in the literature. In the present study, the penetration ability of two components - caffeine nanocrystals and propylene glycol, applied topically on porcine ear skin in the form of a gel, was investigated ex vivo using two confocal Raman microscopes operated at different excitation wavelengths (785nm and 633nm). Several depth profiles were acquired in the fingerprint region and different spectral ranges, i.e., 526-600cm(-1) and 810-880cm(-1) were chosen for independent analysis of caffeine and propylene glycol penetration into the skin, respectively. Multivariate statistical methods such as principal component analysis (PCA) and linear discriminant analysis (LDA) combined with Student's t-test were employed to calculate the maximum penetration depths of each substance (caffeine and propylene glycol). The results show that propylene glycol penetrates significantly deeper than caffeine (20.7-22.0μm versus 12.3-13.0μm) without any penetration enhancement effect on caffeine. The results confirm that different substances, even if applied onto the skin as a mixture, can penetrate differently. The penetration depths of caffeine and propylene glycol obtained using two different confocal Raman microscopes are comparable showing that both types of microscopes are well suited for such investigations and that multivariate statistical PCA-LDA methods combined with Student's t-test are very useful for analyzing the penetration of different substances into the skin.

  8. Effect of different doses of post-emergence-applied iodosulfuron on weed control and grain yield of malt barley (Hordeum distichum L., under Mediterranean conditions

    Directory of Open Access Journals (Sweden)

    Barros José Calado

    2016-01-01

    Full Text Available A study was carried out over a two year period (2009/2010 and 2012/2013 on an experimental farm in the Alentejo region (Beja, in southern Portugal where rainfed malt barley (Hordeum distichum L. is sown at the end of autumn or beginning of winter (November- December. The aim of this experiment was to study the efficiency of the herbicide iodosulfuron-methyl-sodium to control post-emergence broadleaved weeds in this cereal crop. The malt barley crop was established using no-till farming. This technology provides the necessary machine bearing capacity of the soil to assure the post-emergence application of herbicides at two different weed development stages. The herbicide iodosulfuron-methyl-sodium was applied at three doses (5.0, 7.5, and 10.0 g a. i. · ha-1 and at two different broadleaved weed development stages (3 to 4 and 6 to 7 pairs of leaves, that also corresponded to two different crop development stages (beginning of tillering and complete tillering. The results indicated that early herbicide application timing provided a significantly higher efficiency for all the applied herbicide doses, but this better weed control was not reflected in a higher crop grain yield. The lack of a higher crop grain yield was probably due to a crop phytotoxicity of the herbicide, when used at an early application timing.

  9. Neural networks applied to inverters control; Les reseaux de neurones appliques a la commande des convertisseurs

    Energy Technology Data Exchange (ETDEWEB)

    Jammes, B.; Marpinard, J.C.

    1995-12-31

    Neural networks are scarcely applied to power electronics. This attempt includes two different topics: optimal control and computerized simulation. The learning has been performed through output error feedback. For implementation, a buck converter has been used as a voltage pulse generator. (D.L.) 7 refs.

  10. Apparatus and Method for Compensating for Process, Voltage, and Temperature Variation of the Time Delay of a Digital Delay Line

    Science.gov (United States)

    Seefeldt, James (Inventor); Feng, Xiaoxin (Inventor); Roper, Weston (Inventor)

    2013-01-01

    A process, voltage, and temperature (PVT) compensation circuit and a method of continuously generating a delay measure are provided. The compensation circuit includes two delay lines, each delay line providing a delay output. The two delay lines may each include a number of delay elements, which in turn may include one or more current-starved inverters. The number of delay lines may differ between the two delay lines. The delay outputs are provided to a combining circuit that determines an offset pulse based on the two delay outputs and then averages the voltage of the offset pulse to determine a delay measure. The delay measure may be one or more currents or voltages indicating an amount of PVT compensation to apply to input or output signals of an application circuit, such as a memory-bus driver, dynamic random access memory (DRAM), a synchronous DRAM, a processor or other clocked circuit.

  11. Bunch motion in the presence of the self-induced voltage due to a reactive impedance with RF off

    Energy Technology Data Exchange (ETDEWEB)

    Shaposhnikova, E. [European Organization for Nuclear Research, Geneva (Switzerland)

    1996-08-01

    Analytic self-consistent solutions have been found for the nonlinear Vlasov equation describing different types of behaviour with time of an intense bunch under the influence of voltage induced due to a reactive part of broad band impedance. The problem is solved for the particular type of the initial distribution function in longitudinal phase space which is elliptic and corresponds to parabolic line density. This paper is devoted to the consideration of the effects in the machine with RF off. In this case the induced voltage is changing with time and can significantly affect bunch motion. The same method applied in the case with RF on allows the time dependent effects of potential well distortion to be analysed. Numerical estimations for the CERN SPS show that effect of induced voltage is important for beam manipulations with RF off. Measurements of the change in the rate of debunching with intensity can be used to estimate the value of the reactive impedance. (author)

  12. Pollution Maintenance Techniques in Coastal High Voltage Installations

    Directory of Open Access Journals (Sweden)

    E. Pyrgioti

    2011-02-01

    Full Text Available Pollution of outdoor high voltage insulators is a common problem for utilities, with a considerable impact to power system reliability. In an effort to prevent possible flashovers due to pollution, many methods have been applied, aiming to improve the insulation performance, either by suppressing the formation of surface conductivity or by increasing the possible insulation level. In the case of substations, the selection of the appropriate technique is complex due to certain issues correlated to the nature of the installation. In this paper, several techniques usually implemented by utilities, are investigated based on the experienced gained in the case of Crete, a Greek island in southern Europe, where due to the coastal development of the power system, the majority of high voltage installations are exposed to intense marine pollution. The technique of coating insulators with Room Temperature Vulcanized Silicone Rubber (RTV SIR has proved rather efficient and therefore is presented extendedly. Correlation of the material behaviour with environmental conditions is discussed and results from long term monitoring, including environmental parameters and leakage current measurements, in a 150 kV Substation are presented. It is shown that RTV SIR coatings have remarkably suppressed surface activity and that porcelain insulators exhibit different activity period when coated.

  13. Voltage biasing, cyclic voltammetry, & electrical impedance spectroscopy for neural interfaces.

    Science.gov (United States)

    Wilks, Seth J; Richner, Tom J; Brodnick, Sarah K; Kipke, Daryl R; Williams, Justin C; Otto, Kevin J

    2012-02-24

    Electrical impedance spectroscopy (EIS) and cyclic voltammetry (CV) measure properties of the electrode-tissue interface without additional invasive procedures, and can be used to monitor electrode performance over the long term. EIS measures electrical impedance at multiple frequencies, and increases in impedance indicate increased glial scar formation around the device, while cyclic voltammetry measures the charge carrying capacity of the electrode, and indicates how charge is transferred at different voltage levels. As implanted electrodes age, EIS and CV data change, and electrode sites that previously recorded spiking neurons often exhibit significantly lower efficacy for neural recording. The application of a brief voltage pulse to implanted electrode arrays, known as rejuvenation, can bring back spiking activity on otherwise silent electrode sites for a period of time. Rejuvenation alters EIS and CV, and can be monitored by these complementary methods. Typically, EIS is measured daily as an indication of the tissue response at the electrode site. If spikes are absent in a channel that previously had spikes, then CV is used to determine the charge carrying capacity of the electrode site, and rejuvenation can be applied to improve the interface efficacy. CV and EIS are then repeated to check the changes at the electrode-tissue interface, and neural recordings are collected. The overall goal of rejuvenation is to extend the functional lifetime of implanted arrays.

  14. Low Voltage Power Supply Incorporating Ceramic Transformer

    CERN Document Server

    Imori, M

    2007-01-01

    A low voltage power supply provides the regulated output voltage of 1 V from the supply voltage around 48 V. The low voltage power supply incorporates a ceramic transformer which utilizes piezoelectric effect to convert voltage. The ceramic transformer isolates the secondary from the primary, thus providing the ground isolation between the supply and the output voltages. The ceramic transformer takes the place of the conventional magnetic transformer. The ceramic transformer is constructed from a ceramic bar and does not include any magnetic material. So the low voltage power supply can operate under a magnetic field. The output voltage is stabilized by feedback. A feedback loop consists of an error amplifier, a voltage controlled oscillator and a driver circuit. The amplitude ratio of the transformer has dependence on the frequency, which is utilized to stabilize the output voltage. The low voltage power supply is investigated on the analogy of the high voltage power supply similarly incorporating the cerami...

  15. Variation-aware adaptive voltage scaling for digital CMOS circuits

    CERN Document Server

    Wirnshofer, Martin

    2013-01-01

    Increasing performance demands in integrated circuits, together with limited energy budgets, force IC designers to find new ways of saving power. One innovative way is the presented adaptive voltage scaling scheme, which tunes the supply voltage according to the present process, voltage and temperature variations as well as aging. The voltage is adapted “on the fly” by means of in-situ delay monitors to exploit unused timing margin, produced by state-of-the-art worst-case designs. This book discusses the design of the enhanced in-situ delay monitors and the implementation of the complete control-loop comprising the monitors, a control-logic and an on-chip voltage regulator. An analytical Markov-based model of the control-loop is derived to analyze its robustness and stability. Variation-Aware Adaptive Voltage Scaling for Digital CMOS Circuits provides an in-depth assessment of the proposed voltage scaling scheme when applied to an arithmetic and an image processing circuit. This book is written for engine...

  16. Modular High Voltage Power Supply

    Energy Technology Data Exchange (ETDEWEB)

    Newell, Matthew R. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2017-05-18

    The goal of this project is to develop a modular high voltage power supply that will meet the needs of safeguards applications and provide a modular plug and play supply for use with standard electronic racks.

  17. Reliability criteria for voltage stability

    Energy Technology Data Exchange (ETDEWEB)

    Taylor, Carson W.; Silverstein, Brian L. [Bonneville Power Administration, Portland, OR (United States)

    1994-12-31

    In face of costs pressures, there is need to allocate scare resources more effectively in order to achieve voltage stability. This naturally leads to development of probabilistic criteria and notions of rick management. In this paper it is presented a discussion about criteria for long term voltage stability limited to the case in which the time frames are topically several minutes. (author) 14 refs., 1 fig.

  18. A Voltage Quality Detection Method

    DEFF Research Database (Denmark)

    Chen, Zhe; Wei, Mu

    2008-01-01

    This paper presents a voltage quality detection method based on a phase-locked loop (PLL) technique. The technique can detect the voltage magnitude and phase angle of each individual phase under both normal and fault power system conditions. The proposed method has the potential to evaluate vario...... power quality disturbances, such as interruptions, sags and imbalances. Simulation studies have been performed. The effectiveness of the proposed method has been demonstrated under the simulated typical power disturbances....

  19. ANN BASED ONLINE ESTIMATION OF VOLTAGE COLLAPSE PROXIMITY INDICATOR

    Directory of Open Access Journals (Sweden)

    G. Balamurugan

    2010-07-01

    Full Text Available Voltage stability has recently become a challenging issue in many power systems. There are different methods used to study the voltage collapse phenomenon but most of them take significant computation time and are not suitable for on-line applications. Fast voltage stability assessment tools are required in order to ensure the secureoperation of the present day power systems, as voltage collapse can occur quite abruptly in systems. Therefore a new ANN based on-line approach that requires minimum input for estimation of voltage collapse proximity indicator for each critical bus under normal and contingent conditions is developed in this paper. Test results onIEEE-14 bus system are presented to show its computational accuracy.

  20. Binary Versus Decade Inductive Voltage Divider Comparison and Error Decomposition

    Science.gov (United States)

    1995-08-01

    1995 IEEE Authorized licensed use limited to: US Naval Academy. Downloaded on January 30, 2009 at 11:28 from IEEE Xplore . Restrictions apply...Downloaded on January 30, 2009 at 11:28 from IEEE Xplore . Restrictions apply. 906 s, A U U U U U l f U U J s, sa I IEEE TRANSACTIONS ON...30, 2009 at 11:28 from IEEE Xplore . Restrictions apply. AVRAMOV-ZAMUROVIC et al.: BINARY VERSUS DECADE INDUCTIVE VOLTAGE DIVIDER COMPARISON AND ERROR

  1. Locational Pricing to Mitigate Voltage Problems Caused by High PV Penetration

    Directory of Open Access Journals (Sweden)

    Sam Weckx

    2015-05-01

    Full Text Available In this paper, a locational marginal pricing algorithm is proposed to control the voltage in unbalanced distribution grids. The increasing amount of photovoltaic (PV generation installed in the grid may cause the voltage to rise to unacceptable levels during periods of low consumption. With locational prices, the distribution system operator can steer the reactive power consumption and active power curtailment of PV panels to guarantee a safe network operation. Flexible loads also respond to these prices. A distributed gradient algorithm automatically defines the locational prices that avoid voltage problems. Using these locational prices results in a minimum cost for the distribution operator to control the voltage. Locational prices can differ between the three phases in unbalanced grids. This is caused by a higher consumption or production in one of the phases compared to the other phases and provides the opportunity for arbitrage, where power is transferred from a phase with a low price to a phase with a high price. The effect of arbitrage is analyzed. The proposed algorithm is applied to an existing three-phase four-wire radial grid. Several simulations with realistic data are performed.

  2. Topological phase transition in hexagonal boron-nitride bilayers modulated by gate voltage

    Science.gov (United States)

    Jin, Guojun; Zhai, Xuechao

    2013-03-01

    We study the gate-voltage modulated electronic properties of hexagonal boron-nitride bilayers with two different stacking structures in the presence of intrinsic and Rashba spin-orbit interactions. Our analytical results show that there are striking cooperation effects arising from the spin-orbit interactions and the interlayer bias voltage. For realizing topological phase transition, in contrast to a gated graphene bilayer for increasing its energy gap, the energy gap of a boron-nitride bilayer is significantly reduced by an applied gate voltage. For the AA stacking-bilayer which has the inversion symmetry, a strong topological phase is found, and there is an interesting reentrant behavior from a normal phase to a topological phase and then to a normal phase again, characterized by the topological index. Therefore, the gate voltage modulated AA-boron nitride bilayer can be taken as a newcomer of the topological insulator family. For the AB stacking-bilayer which is lack of the inversion symmetry, it is always topologically trivial, but exhibits an unusual quantum Hall phase with four degenerate low-energy states localized at a single edge. It is suggested that these theoretical findings could be verified experimentally in the transport properties of boron-nitride bylayers. This research was supported by the NSFC (Nos. 60876065, 11074108), PAPD, and NBRPC (Nos. 2009CB929504, 2011CB922102).

  3. A matter of quantum voltages.

    Science.gov (United States)

    Sellner, Bernhard; Kathmann, Shawn M

    2014-11-14

    Voltages inside matter are relevant to crystallization, materials science, biology, catalysis, and aqueous chemistry. The variation of voltages in matter can be measured by experiment, however, modern supercomputers allow the calculation of accurate quantum voltages with spatial resolutions of bulk systems well beyond what can currently be measured provided a sufficient level of theory is employed. Of particular interest is the Mean Inner Potential (V(o))--the spatial average of these quantum voltages referenced to the vacuum. Here we establish a protocol to reliably evaluate V(o) from quantum calculations. 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 V(o) for vitrified water and salt crystals and demonstrate the impact of covalent and ionic bonding as well as intermolecular/atomic interactions. Certain aspects in this regard are highlighted making use of simple model systems/approximations. Furthermore, we predict V(o) 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.

  4. Low voltage lightning arresters. Components. Low voltage grids; Parafoudres basse tension. Composants. Reseaux basse tension

    Energy Technology Data Exchange (ETDEWEB)

    Rousseau, A. [Assistance Protection System SAS, 94 - Cachan (France)

    2003-08-01

    Electrical equipments used in domestic and industrial applications are more and more sensible to overvoltages because of the massive use of electronic components in these equipments and appliances. Overvoltages do not propagate only with power lines but also through phone lines, coaxial cables, data networks, and even through grounding circuits. The informations about low voltage grids, useful for the selection of lightning arresters are presented in this article. In the ideal case, each possible way of input for overvoltage currents must be protected. The components used in lightning arresters have improved for a better reliability, a better energy resistance and a better protection level. These components are also presented in this article: 1 - technical and standard evolution: improvement of the understanding of low voltage phenomena, standards evolution, recall of basic definitions and data about lightning protection; 2 - components: varistors, spark gaps, silicon-based solid components, aging and end of life, decoupling components (thermistors, resistors, inductors); 3 - low voltage grids: different types of energy networks, transmission of overvoltages on low voltage networks (overvoltages due to lightning, or power station actuating, temporary overvoltages), influence of lightning conductors and lightning strikes close to the building structure, statistical data about lightning overvoltages on low voltage grids, protection and risk analysis. (J.S.)

  5. Estimation of line flows and bus voltages using decision trees

    Energy Technology Data Exchange (ETDEWEB)

    Yang, C.C.; Hsu, Y.Y. (National Taiwan Univ., Taipei (Taiwan, Province of China). Dept. of Electrical Engineering)

    1994-08-01

    A machine learning method called the ID3 (Interative Dichotomizer 3) approach is presented for the estimation of line flows and bus voltages following an outage event. A decision tree which is capable of generating the desired line flows and bus voltages are created using the training patterns which are compiled from the historical operating records of Taiwan power system. The established decision tree contains the knowledge which is essential for line flow and bus voltage prediction. Thus, it can be applied to estimate line flows and bus voltages of a system in an efficient manner. The effectiveness of the proposed ID3 approach is demonstrated by security assessment of Taiwan power system which contains 170 buses and 207 lines.

  6. A Quantities Method of Induction Motor Under Unbalanced Voltage Conditions

    Directory of Open Access Journals (Sweden)

    Ayong Hiendro

    2010-08-01

    Full Text Available The most complete definition for the voltage unbalance is using complex voltage unbalance factor (CVUF that consists of its magnitude and angle. Unfortunately, the definition did not distinguish between undervoltage and overvoltage unbalance conditions. In this paper, the analysis of the motor is performed using the method of symmetrical component and MATLAB software is used to investigate the performance of induction motor. The simulation results show that the International Electrotechnical Commission (IEC definition of the voltage unbalance can be applied to evaluate total copper losses precisely. However, the phase angle of unbalance factor must be included for accurate predicting of peak currents and peak copper losses of the phase windings of the motor.The unbalanced conditions which distinguish between under and over voltage unbalance must also be taken into consideration for assessing all the quantities.

  7. Time varying voltage combustion control and diagnostics sensor

    Science.gov (United States)

    Chorpening, Benjamin T.; Thornton, Jimmy D.; Huckaby, E. David; Fincham, William

    2011-04-19

    A time-varying voltage is applied to an electrode, or a pair of electrodes, of a sensor installed in a fuel nozzle disposed adjacent the combustion zone of a continuous combustion system, such as of the gas turbine engine type. The time-varying voltage induces a time-varying current in the flame which is measured and used to determine flame capacitance using AC electrical circuit analysis. Flame capacitance is used to accurately determine the position of the flame from the sensor and the fuel/air ratio. The fuel and/or air flow rate (s) is/are then adjusted to provide reduced flame instability problems such as flashback, combustion dynamics and lean blowout, as well as reduced emissions. The time-varying voltage may be an alternating voltage and the time-varying current may be an alternating current.

  8. Current and Voltage Conveyors in Current- and Voltage-Mode Precision Full-Wave Rectifiers

    Directory of Open Access Journals (Sweden)

    J. Koton

    2011-04-01

    Full Text Available In this paper new versatile precision full-wave rectifiers using current and/or voltage conveyors as active elements and two diodes are presented. The performance of these circuit solutions is analysed and compared to the opamp based precision rectifier. To analyze the behavior of the functional blocks, the frequency dependent RMS error and DC transient value are evaluated for different values of input voltage amplitudes. Furthermore, experimental results are given that show the feasibilities of the conveyor based rectifiers superior to the corresponding operational amplifier based topology.

  9. VOLTAGE COMPENSATION USING ARTIFICIAL NEURAL NETWORK

    African Journals Online (AJOL)

    VOLTAGE COMPENSATION USING ARTIFICIAL NEURAL NETWORK: A CASE STUDY OF RUMUOLA DISTRIBUTION NETWORK. ... The artificial neural networks controller engaged to controlling the dynamic voltage ... Article Metrics.

  10. Requirement of ultra-high voltage GIS arrester to voltage gradient of metal-oxide varistor

    Institute of Scientific and Technical Information of China (English)

    HE JinLiang; HU Jun; MENG BoWen; ZHANG Bo; ZHU Bin; CHEN ShuiMing; ZENG Rong

    2009-01-01

    The surge arrestor with excellent protection characteristics would decrease the overvoltage level ap-plied on the power apparatus to reduce their insulation levels and manufacturing bottleneck. The ar-restor for the 1000-kV ultra-high voltage ac power transmission system is designed as tank-type structure. The field-circuit combination numerical method combining the three-dimensional finite ele-ment method with circuit is proposed to analyze the potential distribution of GIS arrester. By comparing several design schemes, the most effective method to improve the potential distribution along the varistor column is to increase the voltage gradient of the ZnO varistor. Synthesizing several influential factors, the suitable voltage gradient of ZnO varistor should be controlled to 435 V/mm, and the re-sulted nonuniform degree of the potential distribution along the varistor column inside the GIS arrestor would be controlled smaller than 10%. The result in this paper provides the fundamental technical in-dex for the study of the high voltage gradient ZnO varistors.

  11. Electrospinning of fibrous polymer scaffolds using positive voltage or negative voltage: a comparative study.

    Science.gov (United States)

    Tong, Ho-Wang; Wang, Min

    2010-10-01

    Electrospinning of fibrous tissue engineering scaffolds has been traditionally conducted using positive voltages. In the current study, positive voltage (PV) electrospinning and negative voltage (NV) electrospinning were investigated for forming fibrous membranes of poly(hydroxybutyrate-co-hydroxyvalerate) (PHBV). In both PV-electrospinning and NV-electrospinning, the fiber diameter generally increased with increasing needle inner diameter and PHBV concentration but decreased with increasing working distance. The use of a conductivity-enhancing surfactant, benzyl triethylammonium chloride (BTEAC), significantly reduced PHBV fiber diameters from the micron scale to the sub-micron scale. Interestingly, with increasing applied voltage, the fiber diameter increased for PV-electrospinning but decreased for NV-electrospinning. The PV-electrospun fibrous membranes from solutions without BTEAC (PVEfm) and with BTEAC (PVEfm-B) and NV-electrospun membranes from solutions without BTEAC (NVEfm) and with BTEAC (NVEfm-B) were characterized in terms of their structure, wettability, thermal properties and tensile properties. Both PVEfm and NVEfm exhibited similar water contact angles (∼104°) but the contact angle of PVEfm-B or NVEfm-B was not measurable. The elongation at break of PVEfm-B or NVEfm-B was significantly higher than that of PVEfm or NVEfm. Using NV-electrospinning or a combination of NV- and PV-electrospinning may be very useful for developing suitable scaffolds for tissue engineering applications.

  12. Local Consequences of Applying International Norms: Differences in the Application of Forest Certification in Northern Sweden, Northern Finland, and Northwest Russia

    Directory of Open Access Journals (Sweden)

    Johanna Johansson

    2009-12-01

    Full Text Available Forest certification, developed in the early 1990s, is a process in which independent assessors grant use of the certification label to producers who meet certain environmental and social criteria set for their forest products. This label was quickly seen to offer a market advantage and to signal corporate social and environmental responsibility. This paper focuses on international norms pertaining to environmental and indigenous rights, as manifested in cases of Forest Stewardship Council (FSC- and Programme for the Endorsement of Forest Certification (PEFC-compatible certification, and how these norms have been applied domestically and perceived locally in different states. Case studies are drawn from northern Sweden, northern Finland, and three regions in northwest Russia. The studies illustrate that the choice and implementation of certification type depend considerably on national infrastructure and market characteristics and result in substantial differences in the impact that international norms have at the local level.

  13. Effect of Aqueous Ammonia Soaking on the Methane Yield and Composition of Digested Manure Fibers Applying Different Ammonia Concentrations and Treatment Durations

    Directory of Open Access Journals (Sweden)

    Chrysoula Mirtsou-Xanthopoulou

    2014-06-01

    Full Text Available The continuously increasing demand for renewable energy sources renders anaerobic digestion one of the most promising technologies for renewable energy production. Due to the animal production intensification, manure is being used as the primary feedstock for most biogas plants. Thus, their economical profitable operation relies on increasing the methane yield from manure, and especially of its solid fraction which is not so easily degradable. In the present study, aqueous ammonia soaking (AAS at six different concentrations in ammonia (5%, 10%, 15%, 20%, 25% and 32% and for 1, 3 and 5 days at 22 °C was applied on digested fibers separated from the effluent of a manure-fed, full-scale anaerobic digester. A methane yield increase from 76% to 104% was achieved during the first series of experiments, while the difference in reagent concentration did not considerably affect the methane yield. It was shown that the optimal duration was three days for both 5% and 25% w/w reagent concentrations in ammonia tested. Carbohydrates and phosphorus content remained unaffected, while a slight decrease in Klason lignin and non-soluble organic nitrogen content was observed after AAS. It is concluded that AAS is a very promising treatment resulting to an overall increase of the methane yield of digested manure fibers from 76% to 265% depending on the conditions and the batch of digested fibers used (an even higher increase of 190%–265% was achieved during the 2nd series of experiments, where different AAS durations were tested, compared to the 1st series were different ammonia concentrations were applied.

  14. Surge currents and voltages at the low voltage power mains during lightning strike to a GSM tower

    Energy Technology Data Exchange (ETDEWEB)

    Markowska, Renata [Bialystok Technical University (Poland)], E-mail: remark@pb.edu.pl

    2007-07-01

    The paper presents the results of numerical calculations of lightning surge currents and voltages in the low voltage power mains system connected to a free standing GSM base station. Direct lightning strike to GSM tower was studied. The analysis concerned the current that flows to the transformer station through AC power mains, the potential difference between the grounding systems of the GSM and the transformer stations and the voltage differences between phase and PE conductors of the power mains underground cable at both the GSM and the transformer sides. The calculations were performed using a numerical program based on the electromagnetic field theory and the method of moments. (author)

  15. Flexible voltage support control for three-phase distributed generation inverters under grid fault

    DEFF Research Database (Denmark)

    Camacho, Antonio; Castilla, Miguel; Miret, Jaume

    2013-01-01

    Operators describe the behavior of the energy source, regulating voltage limits and reactive power injection to remain connected and support the grid under fault. On the basis that different kinds of voltage sags require different voltage support strategies, a flexible control scheme for three phase grid......Ancillary services for distributed generation systems become a challenging issue to smartly integrate renewable energy sources into the grid. Voltage control is one of these ancillary services which can ride through and support the voltage under grid faults. Grid codes from the Transmission System...... connected inverters is proposed. In three phase balanced voltage sags, the inverter should inject reactive power in order to raise the voltage in all phases. In one or two phase faults, the main concern of the distributed generation inverter is to equalize voltages by reducing the negative symmetric...

  16. Verification of a thermal interpretation of BSCCO-2223/Ag current voltage hysteresis

    Science.gov (United States)

    Sastry, P. V. P. S. S.; Nguyen, D. N.; Usak, P.; Schwartz, J.

    2004-03-01

    The current-voltage characteristic hysteresis of Bi-2223 tape in a silver matrix cooled by liquid nitrogen (LN2) at 77 K can be interpreted thermally, i.e. while the ramping-up temperature of the tape is higher than the ramping-down temperature for the same current levels. The reason for this could be hysteresis of the heat transfer coefficient. The coefficient is smaller during ramping up and larger (better cooling) during ramping down. To verify or deny this concept we have measured the surface temperature of the tape at LN2 temperature with and without a thermal insulation sheet upon the tape during ramping up over Ic and ramping down back under Ic. Different ramping rates were applied. The amplitudes of E on the tape was under 0.5 mV cm-1. In spite of measurement error and thermal fluctuations, we observed a difference between the surface temperature curve branch during ramping up and the higher branch during ramping down for a non-insulated tape. Furthermore, the measurements showed that a positive current-voltage (I-V) hysteresis pattern (with the down branch shifted to higher currents and smaller voltages) was observed even with thermal insulation. Under these conditions, however, the down branch of the temperature curve clearly revealed a higher temperature with respect to the up branch of the temperature, contrary to expectations of the thermal interpretation of I-V hysteresis. According to this result, the thermal concept of positive I-V hysteresis under stable cooling conditions can be denied. On the other hand, an accidental voltage drop in the I-V curve was observed on one degraded sample accompanied by a corresponding drop in temperature. This proves the thermal interpretation of voltage drops in I-V curves of locally degraded tapes.

  17. Verification of a thermal interpretation of BSCCO-2223/Ag current-voltage hysteresis

    Energy Technology Data Exchange (ETDEWEB)

    Sastry, P V P S S [Center for Advanced Power Systems, Florida State University, Tallahassee, FL 32310 (United States); Nguyen, D N [Center for Advanced Power Systems, Florida State University, Tallahassee, FL 32310 (United States); Usak, P [Institute of Electrical Engineering, Slovak Academy of Sciences, Dubravska cesta 9, Bratislava, Sk84239 (Slovakia); Schwartz, J [Center for Advanced Power Systems, Florida State University, Tallahassee, FL 32310 (United States)

    2004-03-01

    The current-voltage characteristic hysteresis of Bi-2223 tape in a silver matrix cooled by liquid nitrogen (LN{sub 2}) at 77 K can be interpreted thermally, i.e. while the ramping-up temperature of the tape is higher than the ramping-down temperature for the same current levels. The reason for this could be hysteresis of the heat transfer coefficient. The coefficient is smaller during ramping up and larger (better cooling) during ramping down. To verify or deny this concept we have measured the surface temperature of the tape at LN{sub 2} temperature with and without a thermal insulation sheet upon the tape during ramping up over I{sub c} and ramping down back under I{sub c}. Different ramping rates were applied. The amplitudes of E on the tape was under 0.5 mV cm{sup -1}. In spite of measurement error and thermal fluctuations, we observed a difference between the surface temperature curve branch during ramping up and the higher branch during ramping down for a non-insulated tape. Furthermore, the measurements showed that a positive current-voltage (I-V) hysteresis pattern (with the down branch shifted to higher currents and smaller voltages) was observed even with thermal insulation. Under these conditions, however, the down branch of the temperature curve clearly revealed a higher temperature with respect to the up branch of the temperature, contrary to expectations of the thermal interpretation of I-V hysteresis. According to this result, the thermal concept of positive I-V hysteresis under stable cooling conditions can be denied. On the other hand, an accidental voltage drop in the I-V curve was observed on one degraded sample accompanied by a corresponding drop in temperature. This proves the thermal interpretation of voltage drops in I-V curves of locally degraded tapes.

  18. Effects of iron concentration and redox states on failure of boron-free E-glass fibres under applied stress in different conditions

    Indian Academy of Sciences (India)

    QINGWEI WANG; RICHARD K BROW; HONG LI; ERICA ANN RONCHETTO

    2017-08-01

    Hydrolysis resistance of boron-free E-glass fibre with different total iron oxide (Fe$_2$O$_3$) concentrations, iron redox index and durations of fibre ageing up to 180 days at 50$^{\\circ}$C with 50% relative humidity (RH) was studied. The effect ofageing on the fibre failure measured in two different test environments was examined by using two-point bending method.Based on the differences in failure strains of the fibres obtained from the two conditions as a function of ageing time, theGriffith theory of solid fracture was applied to estimate glass surface energy difference in ageing conditions. The resultsshowed that stress-assisted hydrolysis, when the fibres were under stress, could lead to about 5.18 times reduction in surfaceenergy to account for 2.30 times reduction in fibre failure strain when tested in 50% RH at room temperature.Our study showedthat the boron-free E-glass aged up to 180 days only deteriorated within 13%, independent of total Fe$_2$O$_3$ concentration andFeO/Fe$_2$O$_3$ total ratio, and stress-assisted hydrolysis played a key role during sample testing. Dynamic fatigue of the aged E-glass fibres was also investigated, showing little influence of total Fe$_2$O$_3$ concentration and FeO/Fe$_2$O$_3$ total ratio on fibre stress; corrosion susceptibility was observed.

  19. Voltage Gain Derivation Based on Energy-Balanced Criterion for a Novel Hybrid-Input PV-Wind Power Conversion System

    Directory of Open Access Journals (Sweden)

    Chih-Lung Shen

    2015-01-01

    Full Text Available This paper applies energy-balanced criterion to a novel hybrid-input PV-wind power conversion system (HPWPCS for voltage gain derivation. With the energy-balanced concept, complicated mathematical problems related to voltage gain derivation can be readily resolved. Based on the derived results, it is proven that the proposed HPWPCS is able to process two different kinds of renewable energy resources simultaneously. Even though the HPWPCS includes seven capacitors and three magnetic components, its voltage gain still can be found by the mathematical analysis. In the theoretical derivation, only the energy status of output inductor is dealt with such that complicated derivation procedure is avoided. This analysis method can also be applied to other hybrid green-energy conversion systems. In this paper, a 200 W 50 kHz prototype of HPWPCS is built and examined to verify the mathematical results.

  20. Electrode voltage fall and total voltage of a transient arc

    Science.gov (United States)

    Valensi, F.; Ratovoson, L.; Razafinimanana, M.; Masquère, M.; Freton, P.; Gleizes, A.

    2016-06-01

    This paper deals with an experimental study of the components of a transient arc total voltage with duration of a few tens of ms and a current peak close to 1000 A. The cathode tip is made of graphite whereas the flat anode is made either of copper or of graphite; the electrodes gap is a few mm. The analysis of the electrical parameters is supported and validated by fast imaging and by two models: the first one is a 2D physical model of the arc allowing to calculate both the plasma temperature field and the arc voltage; the second model is able to estimate the transient heating of the graphite electrode. The main aim of the study was to detect the possible change of the cathode voltage fall (CVF) during the first instants of the arc. Indeed it is expected that during the first ms the graphite cathode is rather cool and the main mechanism of the electron emission should be the field effect emission, whereas after several tens of ms the cathode is strongly heated and thermionic emission should be predominant. We have observed some change in the apparent CVF but we have shown that this apparent change can be attributed to the variation of the solid cathode resistance. On the other hand, the possible change of CVF corresponding to the transition between a ‘cold’ and a ‘hot’ cathode should be weak and could not be characterized considering our measurement uncertainty of about 2 V. The arc column voltage (ACV) was estimated by subtracting the electrode voltage fall from the total arc voltage. The experimental transient evolution of the ACV is in very good agreement with the theoretical variation predicted by the model, showing the good ability of the model to study this kind of transient arc.

  1. Adaptive Voltage Control Strategy for Variable-Speed Wind Turbine Connected to a Weak Network

    DEFF Research Database (Denmark)

    Abulanwar, Elsayed; Hu, Weihao; Chen, Zhe

    2016-01-01

    Significant voltage fluctuations and power quality issues pose considerable constraints on the efficient integration of remotely located wind turbines into weak networks. Besides, 3p oscillations arising from the wind shear and tower shadow effects induce further voltage perturbations during...... continuous operation. This study investigates and analyses the repercussions raised by integrating a doubly-fed induction generator wind turbine into an ac network of different parameters and very weak conditions. An adaptive voltage control (AVC) strategy is proposed to retain voltage constancy...

  2. Low voltage electrodeposition of CN x films and study of the effect of the deposition voltage on bonding configurations

    Science.gov (United States)

    Sreejith, K.; Nuwad, J.; Pillai, C. G. S.

    2005-10-01

    Carbon nitride (CN x) films were deposited from acetonitrile at low voltage (150-450 V) through electrodeposition. The films were characterized by atomic force microscopy (AFM), Raman spectroscopy and Fourier transform infrared (FT-IR) spectroscopy. AFM investigations revealed that the grain size was ˜200 nm and roughness was ˜10 nm. The films were found to be continuous and close packed. IR spectra revealed existence of strong sp 3, sp 2 type bonding and weak sp type carbon nitrogen bonds and these bonds were found to increase with voltage. The fraction of sp 3-bonded species in the sample increased in low voltage range and after reaching maximum at 350 V, decreased for higher voltages. However, the concentration of sp 2 CN ring structures in the film increased with increasing voltage. Also, the peak width decreased at low voltages reaching a minimum and increased thereafter. It was observed that the voltage dependent increase in the concentration of polymeric type sp 2 CN (chain) structures was much more pronounced than that of graphitic type sp 2 CN (ring) structures. Raman spectra showed the presence of both the D and G bands. The shift in the G band indicated the presence of nitrogen in the film. The I D/I G ratio was found to increase with the incorporation of nitrogen. Auger electron spectroscopy (AES) showed a clear increase in the nitrogen content with increase in the voltage. The formation of the film could be explained on the basis of dissociation of electrolyte under applied voltage.

  3. Low voltage electrodeposition of CN {sub x} films and study of the effect of the deposition voltage on bonding configurations

    Energy Technology Data Exchange (ETDEWEB)

    Sreejith, K. [Novel Materials and Structural Chemistry Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400 085 (India); Nuwad, J. [Novel Materials and Structural Chemistry Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400 085 (India); Pillai, C.G.S. [Novel Materials and Structural Chemistry Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400 085 (India)]. E-mail: cgspil@apsara.barc.ernet.in

    2005-10-15

    Carbon nitride (CN {sub x}) films were deposited from acetonitrile at low voltage (150-450 V) through electrodeposition. The films were characterized by atomic force microscopy (AFM), Raman spectroscopy and Fourier transform infrared (FT-IR) spectroscopy. AFM investigations revealed that the grain size was {approx}200 nm and roughness was {approx}10 nm. The films were found to be continuous and close packed. IR spectra revealed existence of strong sp{sup 3}, sp{sup 2} type bonding and weak sp type carbon nitrogen bonds and these bonds were found to increase with voltage. The fraction of sp{sup 3}-bonded species in the sample increased in low voltage range and after reaching maximum at 350 V, decreased for higher voltages. However, the concentration of sp{sup 2} CN ring structures in the film increased with increasing voltage. Also, the peak width decreased at low voltages reaching a minimum and increased thereafter. It was observed that the voltage dependent increase in the concentration of polymeric type sp{sup 2} CN (chain) structures was much more pronounced than that of graphitic type sp{sup 2} CN (ring) structures. Raman spectra showed the presence of both the D and G bands. The shift in the G band indicated the presence of nitrogen in the film. The I{sub D}/I{sub G} ratio was found to increase with the incorporation of nitrogen. Auger electron spectroscopy (AES) showed a clear increase in the nitrogen content with increase in the voltage. The formation of the film could be explained on the basis of dissociation of electrolyte under applied voltage.

  4. Finite Element Analysis of voltage effect in the MechanicalBehavior of Diaphragm of Electrostatic Micro-pumps

    Directory of Open Access Journals (Sweden)

    Hamid masoudi sadaghiani

    2016-06-01

    Full Text Available Micro-pumps are one of the most important devices in the field of micro-fluids which have many applications in biomedical engineering. Electrostatic stimulation is one of the mechanisms of stimulation in the micro-pumps that due to low power consumption and comfortable control have very much application in this field. Various phenomena occurs in micro-pumps, electrostatic induction that influence the efficiency and efficacy of this devices. One of these phenomena have been Pull-in instability which is a static phenomenon and occurs when the applied voltage exceeds a critical level. In this case, the diaphragm of micro pump get absorbed into opposite fixed electrode and instability occurs in the system. Therefore, understanding the relationship between pull-in voltage by external factors (for example, the physical characteristics of the device help designers to customize these factors in order to take their required output from device. To estimate the pull-in voltage, for an electrostatic diaphragm computer simulation of finite elements were used. According to the results obtained from the Software, the voltage in steps of 0.025, V = 313/925 which is best answer to unstable Static voltage.The amount of voltage for dynamic mode is approximately 0.91 of static value that is v = 284.41v obtained by software. Comparing the results it can be observed that in the case of unstable Static voltage there is little difference between results. So with this software Mechanical Behavior of Micro Analytical review pages that is difficult and time-consuming can be studied.And the results are used in the design of MEMS that these elements are used in the micro-plates.

  5. Optimal coordinated voltage control of power systems

    Institute of Scientific and Technical Information of China (English)

    LI Yan-jun; HILL David J.; WU Tie-jun

    2006-01-01

    An immune algorithm solution is proposed in this paper to deal with the problem of optimal coordination of local physically based controllers in order to preserve or retain mid and long term voltage stability. This problem is in fact a global coordination control problem which involves not only sequencing and timing different control devices but also tuning the parameters of controllers. A multi-stage coordinated control scheme is presented, aiming at retaining good voltage levels with minimal control efforts and costs after severe disturbances in power systems. A self-pattern-recognized vaccination procedure is developed to transfer effective heuristic information into the new generation of solution candidates to speed up the convergence of the search procedure to global optima. An example of four bus power system case study is investigated to show the effectiveness and efficiency of the proposed algorithm, compared with several existing approaches such as differential dynamic programming and tree-search.

  6. Long term characterization of voltage references

    CERN Document Server

    Halloin, Hubert; Brossard, Julien

    2013-01-01

    We report here the characterization (temperature coefficients and noise level) of selected voltage references in the frequency range from 10^(-5) to 10 Hz. The goal of this work is to update previous studies, with a characterization at lower frequencies, and find voltage references that may be suitable for the space-based interferometry mission eLISA. The requirements of relative output stability of 1 ppm/$\\sqrt{\\text{Hz}}$ down to 0.1 mHz were not met by any of the tested devices, but 4 references approaches the objective : the AD587UQ, the MAX6126AASA50, the LT1021-BCN8-5 and the LT6655BHM. While the first three were already identified as potential devices in previous studies, the later is a new promising candidate using a different technology (bandgap).

  7. Voltage Stability Evaluation Incorporating Wind Power Intermittency

    Institute of Scientific and Technical Information of China (English)

    Libao SHI; Yang ZHAO; Yixin NI; Liangzhong YAO; Masoud BAZARGAN

    2013-01-01

    A simulation framework is proposed to evaluate the voltage stability of power systems incorporating wind power intermittency.Firstly,the power output modelings of three types of wind turbines are discussed.Secondly,the Jensen model is employed to simulate the wind farm with the wake effect.The Monte Carlo based technique is used to conduct the voltage stability evaluation incorporating the randomness of the wind speed based on the Weibull probability distribution.Thirdly,the relative sensitivity index (RSI) is calculated to identify weak buses during analysis.Finally,case studies with different simulation scenarios are carried out.Some statistical results involving weakness probability,expected value and variance of RSI as well as preliminary conclusions are drawn based on numerical simulation results.

  8. Radial MV networks voltage regulation with distribution management system coordinated controller

    Energy Technology Data Exchange (ETDEWEB)

    Bignucolo, Fabio; Caldon, Roberto [University of Padua, Department of Electrical Engineering, Via Gradenigo, 6/A, 35131 Padova (Italy); Prandoni, Valter [CESI Ricerca, Milan (Italy)

    2008-04-15

    The connection of a great number of distributed generation (DG) plants may cause a critical voltage regulation problem in actual medium voltage (MV) radial distribution networks. After a synthetic survey of different strategies reported in literature to solve this problem, a proposal for an active management of the distribution system which makes use of an innovative controller that coordinates the on load tap changer (OLTC) action with the regulation of reactive exchanges between DG plants and feeders, is presented. In order to test the effectiveness of the proposed regulation, the distribution management system coordinated controller (DMSCC) is applied to a realistic radial structure distribution network and its behaviour simulated in managing the MV system during its worst foreseeable working conditions. (author)

  9. Effect of Trace Sn on Pitting Behaviors of High Voltage Anode Aluminum Foil

    Institute of Scientific and Technical Information of China (English)

    Jingbo SONG; Weimin MAO; Hong YANG; Huiping FENG

    2008-01-01

    The effect of trace Sn on the pitting morphology of high voltage anode aluminum foils was investigated. The distributions of microelement Sn, Fe, Si, Cu and Mg in the surface layer of aluminum foils with different Sn content were determined by using a secondary ion mass spectrometer. It was found that the micro-alloyed Sn is enriched at the external surface. The mechanism of pitting behavior of trace Sn on aluminum surface is similar with that of lead. Enrichment of Sn in the surface layer provides large numbers of sites for initiation of pitting corrosion, while pitting sites appeared relatively inhomogenously in the foils without Sn. Sn, as an eco-friendly microelement, can be applied to replace Pb in improving the homogenous pitting behaviors of high voltage aluminum foils, in which the volume fraction of cube texture is not reduced.

  10. Size and voltage dependence of effective anisotropy in sub-100-nm perpendicular magnetic tunnel junctions

    Science.gov (United States)

    Piotrowski, Stephan K.; Bapna, Mukund; Oberdick, Samuel D.; Majetich, Sara A.; Li, Mingen; Chien, C. L.; Ahmed, Rizvi; Victora, R. H.

    2016-07-01

    Magnetic tunnel junctions with perpendicular magnetic anisotropy are investigated using a conductive atomic force microscope. The 1.23 -nm Co40Fe40B20 recording layer coercivity exhibits a size dependence which suggests single-domain behavior for diameters ≤100 nm. Focusing on devices with diameters smaller than 100 nm, we determine the effect of voltage and size on the effective device anisotropy Keff using two different techniques. Keff is extracted both from distributions of the switching fields of the recording and reference layers and from measurement of thermal fluctuations of the recording layer magnetization when a field close to the switching field is applied. The results from both sets of measurements reveal that Keff increases monotonically with decreasing junction diameter, consistent with the size dependence of the demagnetization energy density. We demonstrate that Keff can be controlled with a voltage down to the smallest size measured, 64 nm.

  11. On the application of radio frequency voltages to ion traps via helical resonators

    CERN Document Server

    Siverns, J D; Weidt, S; Hensinger, W K

    2011-01-01

    Ions confined using a Paul trap require a stable, high voltage and low noise radio frequency (RF) potential. We present a guide for the design and construction of a helical coil resonator for a desired frequency that maximises the quality factor for a set of experimental constraints. We provide an in-depth analysis of the system formed from a shielded helical coil and an ion trap by treating the system as a lumped element model. This allows us to predict the resonant frequency and quality factor in terms of the physical parameters of the resonator and the properties of the ion trap. We also compare theoretical predictions with experimental data for different resonators, and predict the voltage applied to the ion trap as a function of the Q-factor, input power and the properties of the resonant circuit.

  12. Increase in the scattering of electric field lines in a new high voltage SOI MESFET

    Science.gov (United States)

    Anvarifard, Mohammad K.

    2016-09-01

    This paper illustrates a new efficient technique to enhance the critical features of a silicon-on-insulator metal-semiconductor field-effect transistor (SOI MESFET) applied in high voltage applications. The structure we proposed utilizes a new method to scatter the electric field lines along the channel region. Realization of two trenches with different materials, which a trench is created in the channel region and the other one is created in the buried oxide, helps the proposed structure to improve the breakdown voltage, driving current, drain-source conductance, minimum noise figure, unilateral power gain and output power density. Exploring the obtained results, the proposed structure has superior electrical performance in comparison to the conventional structure.

  13. The fate of fresh and stored 15N-labelled sheep urine and urea applied to a sandy and a sandy loam soil using different application strategies

    DEFF Research Database (Denmark)

    Sørensen, P.; Jensen, E.S.

    1996-01-01

    .), or it was applied to ryegrass one month after sowing. In a sandy loam soil, 62% of the incorporated urine N and 78% of the incorporated urea N was recovered in three cuts of herbage after 5 months. In a sandy soil, 51-53% of the labelled N was recovered in the herbage and the distribution of labelled N in plant...... and soil was not significantly different for incorporated urine and urea. Almost all the supplied labelled N was accounted for in soil and herbage in the sandy loam soil, whereas 33-34% of the labelled N was unaccounted for in the sandy soil. When the stored urine was applied to the soil surface, 20...... unaccounted for was probably mainly lost by ammonia volatilization. Significantly more urine- than urea-derived N (36 and 19%, respectively) was immobilized in the sandy loam soil, whereas the immobilization of N from urea and urine was similar in the sandy soil (13-16%). The distribution of urine N, whether...

  14. Plasma response to transient high voltage pulses

    Indian Academy of Sciences (India)

    S Kar; S Mukherjee

    2013-07-01

    This review reports on plasma response to transient high voltage pulses in a low pressure unmagnetized plasma. Mainly, the experiments are reviewed, when a disc electrode (metallic and dielectric) is biased pulsed negative or positive. The main aim is to review the electron loss in plasmas and particle balance during the negative pulse electrode biasing, when the applied pulse width is less than the ion plasma period. Though the applied pulse width is less than the ion plasma period, ion rarefaction waves are excited. The solitary electron holes are reviewed for positive pulsed bias to the electrode. Also the excitation of waves (solitary electron and ion holes) is reviewed for a metallic electrode covered by a dielectric material. The wave excitation during and after the pulse withdrawal, excitation and propagation characteristics of various electrostatic plasma waves are reviewed here.

  15. 不同负载工况下牵引变对电网电压不平衡的影响%Research on the influence of traction transformer in different load conditions on voltage unbalance in power supply system

    Institute of Scientific and Technical Information of China (English)

    杨申浩; 李凤婷

    2016-01-01

    In view of the unbalanced voltage problem in power system caused by electrified railway accessing to public substation,A 36-node grid test system and a variety of traction transformers were established on the platform of PSCAD,and the propagation condition of unbalanced voltage caused by electrified railway was analyzed.The voltage unbalance effect on the power system when it connecting traction transformers with balanced or unbalanced load under the condition of alternation commutation phase was researched.The study finds that the rational deployment of traction load can reduce the VUF of PCC less than 2%.The research result of simulation analysis provides theoretical support and engineering application value for transformer selection and load deployment.%针对电气化铁路接入公用变电站造成供电系统电压不平衡的问题,在PSCAD平台上建立了各种牵引变压器模型及36节点的电网测试系统,分析了电气化铁路引起的电压不平衡在系统中的传播情况;研究了轮流换相的条件下多台牵引变接入对称、不对称负载时对电网电压不平衡的影响;研究发现合理调配牵引变负载能使PCC点电压不平衡度低于2%。研究结果可为牵引变的选型和负载的合理调配提供理论支撑,具有工程应用价值。

  16. Study of different ultrasonic focusing methods applied to non destructive testing; Etude de differentes methodes de focalisation ultrasonore appliquees au controle non destructif

    Energy Technology Data Exchange (ETDEWEB)

    El Amrani, M.

    1995-11-17

    The work presented in this thesis concerns the study of different ultrasonic focusing techniques applied to Nondestructive Testing (mechanical focusing and electronic focusing) and compares their capabilities. We have developed a model to predict the ultrasonic field radiated into a solid by water-coupled transducers. The model is based upon the Rayleigh integral formulation, modified to take account the refraction at the liquid-solid interface. The model has been validated by numerous experiments in various configurations. Running this model and the associated software, we have developed new methods to optimize focused transducers and studied the characteristics of the beam generated by transducers using various focusing techniques. (author). 120 refs., 95 figs., 4 appends.

  17. Development of a New Cascade Voltage-Doubler for Voltage Multiplication

    OpenAIRE

    Arash Toudeshki; Norman Mariun; Hashim Hizam; Noor Izzri Abdul Wahab

    2014-01-01

    For more than eight decades, cascade voltage-doubler circuits are used as a method to produce DC output voltage higher than the input voltage. In this paper, the topological developments of cascade voltage-doublers are reviewed. A new circuit configuration for cascade voltage-doubler is presented. This circuit can produce a higher value of the DC output voltage and better output quality compared to the conventional cascade voltage-doubler circuits, with the same number of stages.

  18. Low-Energy Real-Time OS Using Voltage Scheduling Algorithm for Variable Voltage Processors

    OpenAIRE

    Okuma, Takanori; Yasuura, Hiroto

    2001-01-01

    This paper presents a real-time OS based on $ mu $ITRON using proposed voltage scheduling algorithm for variable voltage processors which can vary supply voltage dynamically. The proposed voltage scheduling algorithms assign voltage level for each task dynamically in order to minimize energy consumption under timing constraints. Using the presented real-time OS, running tasks with low supply voltage leads to drastic energy reduction. In addition, the presented voltage scheduling algorithm is ...

  19. Simple buck/boost voltage regulator

    Science.gov (United States)

    Paulkovich, J.; Rodriguez, G. E.

    1980-01-01

    Circuit corrects low or high supply voltage, produces regulated output voltage. Circuit has fewer components because inductory/transformer combination and pulse-width modulator serve double duty. Regulator handles input voltage variation from as low as one half output voltage to as high as input transistor rating. Solar arrays, fuel cells, and thermionic generators might use this regulator.

  20. 30 CFR 18.47 - Voltage limitation.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Voltage limitation. 18.47 Section 18.47 Mineral... § 18.47 Voltage limitation. (a) A tool or switch held in the operator's hand or supported against his... particular voltage(s) are provided in the design and construction of the equipment, its wiring,...