WorldWideScience

Sample records for direct current measurements

  1. Resistivity measurements using a direct current induction method (1963)

    Delaplace, J.; Hillairet, J.

    1964-01-01

    The conventional methods for measuring electrical resistivities necessitate the fixing of electrical contacts on the sample either mechanically or by soldering. Furthermore it is also necessary to carry,out the measurements on low cross-section samples which are not always easy to obtain. Our direct-current induction method on the other hand requires no contacts and can easily be applied to samples of large cross-section. The sample is placed in a uniform magnetic field; at the moment when the current is cut, eddy currents appear in the sample which tend to oppose the disappearance of the field. The way in which the magnetic flux decreases in the sample makes it possible to determine the resistivity of the material. This method has been applied to samples having diameters of between 1 and 30 mm in the case of metals which are good conductors. It gives a value for the local resistivity and makes it possible to detect any variation along a sample. The measurements can be carried out at all temperature from a few degrees absolute to 500 deg. C. We have used the induction method to follow the purification of beryllium by zone-melting; it is in effect possible to estimate the purity of a material by resistivity measurements. We have measured the resistivity along each bar treated by the zone-melting technique and have thus, localised the purest section. High temperature measurements have been carried out on uranium carbide and on iron-aluminium alloys. This method constitutes an interesting means of investigation the resistivity of solid materials. Its accuracy and rapidity make it particularly adapted both to fundamental research and to production control. (authors) [fr

  2. Measurement of direct currents of under 10-10 ampere and of resistances of 1012 Ω for a direct current

    Vagner, J.

    1965-01-01

    Measurement of weak direct currents by Townsend's method using a vibrating condenser electrometer. Development of a current generator giving a pico-ampere independently of the resistance of the circuit used. Development of generators giving currents which may be adjusted continuously and exactly (0.1 to 1 pico-ampere, 1 to 10 pico-amperes, 10 to 100 pico-amperes). Measurement of very high resistances (10 12 Ω) by three different methods. Graphs are made by plotting the value of the resistance against the potential difference applied across it (from 50 milli-volts to 50 volts). Two methods use adjustable current generators and the third is applicable to the measurement of resistances of between 10 7 and 10 13 Ω using a series of condensers ranging from 50 pico-farads to 10 micro-farads. The accuracy of the measurements is between 0. 5 and 1 per cent. (author) [fr

  3. Direct-current proton-beam measurements at Los Alamos

    Sherman, J.; Stevens, R.R.; Schneider, J.D.; Zaugg, T.

    1994-01-01

    Recently, a CW proton accelerator complex was moved from Chalk River Laboratories (CRL) to Los Alamos National Laboratory. This includes a 50-keV dc proton injector with a single-solenoid low-energy beam transport system (LEBT) and a CW 1.25-MeV, 267-MHz radiofrequency quadrupole (RFQ). The move was completed after CRL had achieved 55-mA CW operation at 1.25 MeV using 250-kW klystrode tubes to power the RFQ. These accelerator components are prototypes for the front end of a CW linac required for an accelerator-driven transmutation linac, and they provide early confirmation of some CW accelerator components. The injector (ion source and LEBT) and emittance measuring unit are installed and operational at Los Alamos. The dc microwave ion source has been operated routinely at 50-keV, 75-mA hydrogen-ion current. This ion source has demonstrated very good discharge and H 2 gas efficiencies, and sufficient reliability to complete CW RFQ measurements at CRL. Proton fraction of 75% has been measured with 550-W discharge power. This high proton fraction removes the need for an analyzing magnet. Proton LEBT emittance measurements completed at Los Alamos suggest that improved transmission through the RFQ may be achieved by increasing the solenoid focusing current. Status of the final CW RFQ operation at CRL and the installation of the RFQ at Los Alamos is given

  4. Use of Direct Current Resistivity Measurements to Assess AISI 304 Austenitic Stainless Steel Sensitization

    Mesquita, Ramaiany Carneiro; Mecury, José Manoel Rivas; Tanaka, Auro Atsumi; Sousa, Regina Célia de

    2015-01-01

    This paper describes the feasibility of using direct current electrical resistivity measurements to evaluate AISI 304 austenitic stainless steel sensitization. ASTM A262 – Practice A and double loop electrochemical potentiodynamic reactivation (DL-EPR) tests were performed to assess the degree of sensitization (DoS) qualitatively and quantitatively, and electrical resistivity (ER) was measured by the four-point direct-current potential drop method. The results indicate that the DoS incr...

  5. Development of an instrument for direct ozone production rate measurements: measurement reliability and current limitations

    Sklaveniti, Sofia; Locoge, Nadine; Stevens, Philip S.; Wood, Ezra; Kundu, Shuvashish; Dusanter, Sébastien

    2018-02-01

    Ground-level ozone (O3) is an important pollutant that affects both global climate change and regional air quality, with the latter linked to detrimental effects on both human health and ecosystems. Ozone is not directly emitted in the atmosphere but is formed from chemical reactions involving volatile organic compounds (VOCs), nitrogen oxides (NOx = NO + NO2) and sunlight. The photochemical nature of ozone makes the implementation of reduction strategies challenging and a good understanding of its formation chemistry is fundamental in order to develop efficient strategies of ozone reduction from mitigation measures of primary VOCs and NOx emissions. An instrument for direct measurements of ozone production rates (OPRs) was developed and deployed in the field as part of the IRRONIC (Indiana Radical, Reactivity and Ozone Production Intercomparison) field campaign. The OPR instrument is based on the principle of the previously published MOPS instrument (Measurement of Ozone Production Sensor) but using a different sampling design made of quartz flow tubes and a different Ox (O3 and NO2) conversion-detection scheme composed of an O3-to-NO2 conversion unit and a cavity attenuated phase shift spectroscopy (CAPS) NO2 monitor. Tests performed in the laboratory and in the field, together with model simulations of the radical chemistry occurring inside the flow tubes, were used to assess (i) the reliability of the measurement principle and (ii) potential biases associated with OPR measurements. This publication reports the first field measurements made using this instrument to illustrate its performance. The results showed that a photo-enhanced loss of ozone inside the sampling flow tubes disturbs the measurements. This issue needs to be solved to be able to perform accurate ambient measurements of ozone production rates with the instrument described in this study. However, an attempt was made to investigate the OPR sensitivity to NOx by adding NO inside the instrument

  6. A self-discharge model of Lithium-Sulfur batteries based on direct shuttle current measurement

    Knap, Vaclav; Stroe, Daniel Loan; Swierczynski, Maciej Jozef

    2016-01-01

    . A simple but comprehensive mathematical model of the Li-S battery cell self-discharge based on the shuttle current was developed and is presented. The shuttle current values for the model parameterization were obtained from the direct shuttle current measurements. Furthermore, the battery cell depth......-of-discharge values were recomputed in order to account for the influence of the self-discharge and provide a higher accuracy of the model. Finally, the derived model was successfully validated against laboratory experiments at various conditions....

  7. Direct Reconstruction of Two-Dimensional Currents in Thin Films from Magnetic-Field Measurements

    Meltzer, Alexander Y.; Levin, Eitan; Zeldov, Eli

    2017-12-01

    An accurate determination of microscopic transport and magnetization currents is of central importance for the study of the electric properties of low-dimensional materials and interfaces, of superconducting thin films, and of electronic devices. Current distribution is usually derived from the measurement of the perpendicular component of the magnetic field above the surface of the sample, followed by numerical inversion of the Biot-Savart law. The inversion is commonly obtained by deriving the current stream function g , which is then differentiated in order to obtain the current distribution. However, this two-step procedure requires filtering at each step and, as a result, oversmooths the solution. To avoid this oversmoothing, we develop a direct procedure for inversion of the magnetic field that avoids use of the stream function. This approach provides enhanced accuracy of current reconstruction over a wide range of noise levels. We further introduce a reflection procedure that allows for the reconstruction of currents that cross the boundaries of the measurement window. The effectiveness of our approach is demonstrated by several numerical examples.

  8. Edge effects in four-point direct current potential drop measurements on metal plates

    Lu, Y; Bowler, N; Bowler, J R; Huang, Y

    2009-01-01

    Four-point direct current potential drop (DCPD) measurements are commonly used to measure the conductivity (or resistivity) of semiconductors and ferrous or non-ferrous metals. The measured electrical potential difference is often interpreted in terms of analytic expressions developed for large plates that are either 'thin' or 'thick' relative to the probe length. It is well known that the presence of the back surface of a plate leads to a solution expressed in terms of an infinite series representing the current source and its images. This approach can be generalized to account for multiple surfaces in order to obtain a solution for a finite plate, but convergence of the series is poor when the plate dimensions are similar to or smaller than the separation of the current injection and extraction points. Here, Fourier series representations of the infinite sums are obtained. It is shown that the Fourier series converge with many fewer terms than the series obtained from image theory, for plates with dimensions similar to or smaller than the separation of the current injection and extraction points. Comparing calculated results for the potential drop obtained by a four-point probe centred on finite plates of varying dimension, with those for a probe in contact with a large (laterally infinite) plate, estimates are given of the uncertainty due to edge effects in measurements on small plates interpreted using analytic formulae developed for large plates. It is also shown that these uncertainties due to edge effects are reduced, for a given plate size, if the probe pick-up points are moved closer to the current injection points, rather than adopting the common arrangement in which the four probe points are equally spaced. Calculated values of DCPD are compared with experimental data taken on aluminium and spring-steel plates of various sizes and excellent agreement is obtained.

  9. Edge effects in four-point direct current potential drop measurements on metal plates

    Lu, Y.; Bowler, N.; Bowler, J. R.; Huang, Y.

    2009-07-01

    Four-point direct current potential drop (DCPD) measurements are commonly used to measure the conductivity (or resistivity) of semiconductors and ferrous or non-ferrous metals. The measured electrical potential difference is often interpreted in terms of analytic expressions developed for large plates that are either 'thin' or 'thick' relative to the probe length. It is well known that the presence of the back surface of a plate leads to a solution expressed in terms of an infinite series representing the current source and its images. This approach can be generalized to account for multiple surfaces in order to obtain a solution for a finite plate, but convergence of the series is poor when the plate dimensions are similar to or smaller than the separation of the current injection and extraction points. Here, Fourier series representations of the infinite sums are obtained. It is shown that the Fourier series converge with many fewer terms than the series obtained from image theory, for plates with dimensions similar to or smaller than the separation of the current injection and extraction points. Comparing calculated results for the potential drop obtained by a four-point probe centred on finite plates of varying dimension, with those for a probe in contact with a large (laterally infinite) plate, estimates are given of the uncertainty due to edge effects in measurements on small plates interpreted using analytic formulae developed for large plates. It is also shown that these uncertainties due to edge effects are reduced, for a given plate size, if the probe pick-up points are moved closer to the current injection points, rather than adopting the common arrangement in which the four probe points are equally spaced. Calculated values of DCPD are compared with experimental data taken on aluminium and spring-steel plates of various sizes and excellent agreement is obtained.

  10. Four-point probe measurements of a direct current potential drop on layered conductive cylinders

    Lu, Yi; Bowler, John R

    2012-01-01

    We have determined the steady state electric field due to direct current flowing via point contacts at the cylindrical surface of a uniformly layered conductive rod of finite length. The solution allows one to use four-point probe potential drop measurements to estimate the conductivity or thickness of the layer assuming that the other parameters are known. The electrical potential in the rod has a zero radial derivative at its surface except at the injection and extractions points. This means that the required solution can be expressed in terms of a Green’s function satisfying a Neumann boundary condition. Four-point measurements have been made to demonstrate the validity of theoretical results. (paper)

  11. Four-point probe measurements of a direct current potential drop on layered conductive cylinders

    Lu, Yi; Bowler, John R.

    2012-11-01

    We have determined the steady state electric field due to direct current flowing via point contacts at the cylindrical surface of a uniformly layered conductive rod of finite length. The solution allows one to use four-point probe potential drop measurements to estimate the conductivity or thickness of the layer assuming that the other parameters are known. The electrical potential in the rod has a zero radial derivative at its surface except at the injection and extractions points. This means that the required solution can be expressed in terms of a Green’s function satisfying a Neumann boundary condition. Four-point measurements have been made to demonstrate the validity of theoretical results.

  12. Methods for Specific Electrode Resistance Measurement during Transcranial Direct Current Stimulation

    Khadka, Niranjan; Rahman, Asif; Sarantos, Chris; Truong, Dennis Q.; Bikson, Marom

    2014-01-01

    Background Transcranial Direct Current Stimulation (tDCS) is investigated to treat a wide range of neuropsychiatric disorders, for rehabilitation, and for enhancing cognitive performance. The monitoring of electrode resistance before and during tDCS is considered important for tolerability and safety, where an unusually high resistance is indicative of undesired electrode or poor skin contact conditions. Conventional resistance measurement methods do not isolate individual electrode resistance but rather measures overall voltage. Moreover, for HD-tDCS devices, cross talk across electrodes makes concurrent resistance monitoring unreliable. Objective We propose a novel method for monitoring of the individual electrode resistance during tDCS, using a super-position of direct current with a test-signal (low-intensity and low-frequency sinusoids with electrode– specific frequencies) and a single sentinel electrode (not used for DC). Methods To validate this methodology, we developed lumped-parameter models of two and multi-electrode tDCS. Approaches with and without a sentinel electrode were solved and underlying assumptions identified. Assumptions were tested and parameterized in healthy participants using forearm stimulation combining tDCS (2 mA) and sinusoidal test-signals (38 μA and 76 μA peak to peak at 1 Hz, 10 Hz, and 100 Hz) and an in vitro test (where varied electrode failure modes were created). DC and AC component voltages across the electrodes were compared and participants were asked to rate subjective pain. Results A sentinel electrode is required to isolate electrode resistance in a two-electrode tDCS system. For multi-electrode resistance tracking, cross talk was aggravated with electrode proximity and current/resistance mismatches, but could be corrected using proposed approaches. Average voltage and average pain scores were not significantly different across test current intensities and frequencies (two-way repeated measures ANOVA) indicating the

  13. Application possibility of the direct current conduction method for nondestructive crack measurement

    Riedl, R.

    1982-01-01

    An important value to determine the danger of cracks is the determination of crack depths. The crack depth can be determined quite accurate by means of the direct current conduction method, if one holds onto certain rules. Often complicated experimental set-ups are applied. However, portable commercial devices can be obtained that can be used for partial fluxation, that yield good results. By means of two examples: crack conduction samples in which the built-up of a constant-cracking is persued up to a certain depth, as well as the persuasion of an continuing crack in a bearing cylinder, shall be demonstrated that is very well possible to record accurate profiles with commercial devices and to avoid expensive measurement devices. (orig.) [de

  14. Combined local current distribution measurements and high resolution neutron radiography of operating direct methanol fuel cells

    Schroeder, Alexander; Wippermann, Klaus [Forschungszentrum Juelich GmbH (Germany). Inst. of Energy Research, IEF-3: Fuel Cells; Sanders, Tilman [RWTH Aachen (DE). Inst. for Power Electronics and Electrical Drives (ISEA); Arlt, Tobias [Helmholtz Centre Berlin (Germany). Inst. for Applied Materials

    2010-07-01

    Neutron radiography allows the investigation of the local fluid distribution in direct methanol fuel cells (DMFCs) under operating conditions. Spatial resolutions in the order of some tens of micrometers at the full test cell area are achieved. This offers the possibility to study practice-oriented, large stack cells with an active area of several hundred cm{sup 2} as well as specially designed, small test cells with an area of some cm{sup 2}. Combined studies of high resolution neutron radiography and segmented cell measurements are especially valuable, because they enable a correlation of local fluid distribution and local performance [1, 2]. The knowledge of this interdependency is essential to optimise the water management and performance respecting a homogeneous fluid, current and temperature distribution and to achieve high performance and durability of DMFCs. (orig.)

  15. Anodal transcranial direct current stimulation reduces psychophysically measured surround suppression in the human visual cortex.

    Daniel P Spiegel

    Full Text Available Transcranial direct current stimulation (tDCS is a safe, non-invasive technique for transiently modulating the balance of excitation and inhibition within the human brain. It has been reported that anodal tDCS can reduce both GABA mediated inhibition and GABA concentration within the human motor cortex. As GABA mediated inhibition is thought to be a key modulator of plasticity within the adult brain, these findings have broad implications for the future use of tDCS. It is important, therefore, to establish whether tDCS can exert similar effects within non-motor brain areas. The aim of this study was to assess whether anodal tDCS could reduce inhibitory interactions within the human visual cortex. Psychophysical measures of surround suppression were used as an index of inhibition within V1. Overlay suppression, which is thought to originate within the lateral geniculate nucleus (LGN, was also measured as a control. Anodal stimulation of the occipital poles significantly reduced psychophysical surround suppression, but had no effect on overlay suppression. This effect was specific to anodal stimulation as cathodal stimulation had no effect on either measure. These psychophysical results provide the first evidence for tDCS-induced reductions of intracortical inhibition within the human visual cortex.

  16. Direct-reading inhalable dust monitoring--an assessment of current measurement methods.

    Thorpe, Andrew; Walsh, Peter T

    2013-08-01

    Direct-reading dust monitors designed specifically to measure the inhalable fraction of airborne dust are not widely available. Current practice therefore often involves comparing the response of photometer-type dust monitors with the concentration measured with a reference gravimetric inhalable sampler, which is used to adjust the dust monitor measurement. However, changes in airborne particle size can result in significant errors in the estimation of inhalable concentration by this method. The main aim of this study was to assess how these dust monitors behave when challenged with airborne dust containing particles in the inhalable size range and also to investigate alternative dust monitors whose response might not be as prone to variations in particle size or that could be adapted to measure inhalable dust concentration. Several photometer-type dust monitors and a Respicon TM, tapered element oscillating microbalance (TEOM) personal dust monitor (PDM) 3600, TEOM 1400, and Dustrak DRX were assessed for the measurement of airborne inhalable dust during laboratory and field trials. The PDM was modified to allow it to sample and measure larger particles in the inhalable size range. During the laboratory tests, the dust monitors and reference gravimetric samplers were challenged inside a large dust tunnel with aerosols of industrial dusts known to present an inhalable hazard and aluminium oxide powders with a range of discrete particle sizes. A constant concentration of each dust type was generated and peak concentrations of larger particles were periodically introduced to investigate the effects of sudden changes in particle size on monitor calibration. The PDM, Respicon, and DataRam photometer were also assessed during field trials at a bakery, joinery, and a grain mill. Laboratory results showed that the Respicon, modified PDM, and TEOM 1400 observed good linearity for all types of dust when compared with measurements made with a reference IOM sampler; the

  17. Direct Measurement of Nuclear Dependence of Charged Current Quasielasticlike Neutrino Interactions Using MINERvA

    Betancourt, M.; Ghosh, A.; Walton, T.; Altinok, O.; Bellantoni, L.; Bercellie, A.; Bodek, A.; Bravar, A.; Cai, T.; Martinez Caicedo, D. A.; Carneiro, M. F.; Dytman, S. A.; Díaz, G. A.; Felix, J.; Fields, L.; Fine, R.; Galindo, R.; Gallagher, H.; Ghosh, A.; Golan, T.; Gran, R.; Harris, D. A.; Higuera, A.; Hurtado, K.; Kiveni, M.; Kleykamp, J.; Le, T.; Maher, E.; Manly, S.; Mann, W. A.; Marshall, C. M.; McFarland, K. S.; McGivern, C. L.; McGowan, A. M.; Messerly, B.; Miller, J.; Mislivec, A.; Morfín, J. G.; Mousseau, J.; Naples, D.; Nelson, J. K.; Norrick, A.; Nuruzzaman, Patrick, C. E.; Perdue, G. N.; Ramírez, M. A.; Ren, L.; Rimal, D.; Rodrigues, P. A.; Ruterbories, D.; Schellman, H.; Sobczyk, J. T.; Solano Salinas, C. J.; Sánchez Falero, S.; Valencia, E.; Wolcott, J.; Wospakrik, M.; Yaeggy, B.; Minerva Collaboration

    2017-08-01

    Charged-current νμ interactions on carbon, iron, and lead with a final state hadronic system of one or more protons with zero mesons are used to investigate the influence of the nuclear environment on quasielasticlike interactions. The transferred four-momentum squared to the target nucleus, Q2, is reconstructed based on the kinematics of the leading proton, and differential cross sections versus Q2 and the cross-section ratios of iron, lead, and carbon to scintillator are measured for the first time in a single experiment. The measurements show a dependence on the atomic number. While the quasielasticlike scattering on carbon is compatible with predictions, the trends exhibited by scattering on iron and lead favor a prediction with intranuclear rescattering of hadrons accounted for by a conventional particle cascade treatment. These measurements help discriminate between different models of both initial state nucleons and final state interactions used in the neutrino oscillation experiments.

  18. Modulated Current Drive Measurements

    Petty, C.C.; Lohr, J.; Luce, T.C.; Prater, R.; Cox, W.A.; Forest, C.B.; Jayakumar, R.J.; Makowski, M.A.

    2005-01-01

    A new measurement approach is presented which directly determines the noninductive current profile from the periodic response of the motional Stark effect (MSE) signals to the slow modulation of the external current drive source. A Fourier transform of the poloidal magnetic flux diffusion equation is used to analyze the MSE data. An example of this measurement technique is shown using modulated electron cyclotron current drive (ECCD) discharges from the DIII-D tokamak

  19. Improved reading measures in adults with dyslexia following transcranial direct current stimulation treatment.

    Heth, Inbahl; Lavidor, Michal

    2015-04-01

    To better understand the contribution of the dorsal system to word reading, we explored transcranial direct current stimulation (tDCS) effects when adults with developmental dyslexia received active stimulation over the visual extrastriate area MT/V5, which is dominated by magnocellular input. Stimulation was administered in 5 sessions spread over two weeks, and reading speed and accuracy as well as reading fluency were assessed before, immediately after, and a week after the end of the treatment. A control group of adults with developmental dyslexia matched for age, gender, reading level, vocabulary and block-design WAIS-III sub-tests and reading level was exposed to the same protocol but with sham stimulation. The results revealed that active, but not sham stimulation, significantly improved reading speed and fluency. This finding suggests that the dorsal stream may play a role in efficient retrieval from the orthographic input lexicon in the lexical route. It also underscores the potential of tDCS as an intervention tool for improving reading speed, at least in adults with developmental dyslexia. Copyright © 2015 Elsevier Ltd. All rights reserved.

  20. Measurements of the large-scale direct-current Earth potential and possible implications for the geomagnetic dynamo.

    1985-07-05

    The magnitude of the large-scale direct-current earth potential was measured on a section of a recently laid transatlantic telecommunications cable. Analysis of the data acquired on the 4476-kilometer cable yielded a mean direct-current potential drop of less than about 0.072 +/- 0.050 millivolts per kilometer. Interpreted in terms of a generation of the potential by the earth's geodynamo, such a small value of the mean potential implies that the toroidal and poloidal magnetic fields of the dynamo are approximately equal at the core-mantle boundary.

  1. Research on corrosion mechanism of suspension insulator steel foot of direct current system and measures for corrosion inhibition

    Chen, He; Yang, Yueguang; Su, Guolei; Wang, Xiaoqing; Zhang, Hourong; Sun, Xiaoyu; Fan, Youping

    2017-09-01

    There are increasingly serious electrocorrosion phenomena on insulator hardware caused by direct current transmission due to the wide-range popularization of extra high voltage direct current transmission engineering in our country. Steel foot corrosion is the main corrosion for insulators on positive polarity side of transmission lines. On one hand, the corrosion leads to the tapering off of steel foot diameter, having a direct influence on mechanical property of insulators; on the other hand, in condition of corrosion on steel foot wrapped in porcelain ware, the volume of the corrosion product is at least 50% more than that of the original steel foot, leading to bursting of porcelain ware, threatening safe operation of transmission lines. Therefore, it is necessary to conduct research on the phenomenon and propose feasible measures for corrosion inhibition. Starting with the corrosion mechanism, this article proposes two measures for corrosion inhibition, and verifies the inhibition effect in laboratory conditions, providing reference for application in engineering.

  2. Direct current linear measurement sub-assembly data and test methods. Nuclear electronic equipment for control and monitoring panel

    1977-12-01

    The M.C.H./M.E.N.T.3 document is concerned with sub-assemblies intended for measuring on a linear scale the neutron fluence rate or radiation dose rate when connected with nuclear detectors working in current. The symbols used are described. Some definitions and a bibliography are given. The main characteristics of direct current linear measurement sub-assemblies are then described together with corresponding test methods. This type of instrument indicates on a linear scale the level of a direct current applied to its input. The document reviews linear sub-assemblies for general purpose applications, difference amplifiers for monitoring, and averaging amplifiers. The document is intended for electronics manufacturers, designers, persons participating in acceptance trials and plant operators [fr

  3. Suspended sediment dynamics in a large-scale turbidity current: Direct measurements from the deep-water Congo Canyon

    Simmons, S.; Azpiroz, M.; Cartigny, M.; Clare, M. A.; Parsons, D. R.; Sumner, E.; Talling, P. J.

    2016-12-01

    Turbidity currents that transport sediment to the deep ocean deposit a greater volume of sediment than any other process on Earth. To date, only a handful of studies have directly measured turbidity currents, with flow durations ranging from a few minutes to a few hours. Our understanding of turbidity current dynamics is therefore largely derived from scaled laboratory experiments and numerical modelling. Recent years have seen the first field-scale measurements of depth-resolved velocity profiles, but sediment concentration (a key parameter for turbidity currents) remains elusive. Here, we present high resolution measurements of deep-water turbidity currents from the Congo Canyon; one of the world's largest submarine canyons. Direct measurements using acoustic Doppler current profilers (ADCPs) show that flows can last for many days, rather than hours as seen elsewhere, and provide the first quantification of concentration and grain size within deep-water turbidity currents.Velocity and backscatter were measured at 5 second intervals by an ADCP suspended 80 m above the canyon floor, at 2000 m water depth. A novel inversion method using multiple ADCP frequencies enabled quantification of sediment concentration and grain size within the flows. We identify high concentrations of coarse sediment within a thin frontal cell, which outruns a thicker, trailing body. Thus, the flows grow in length while propagating down-canyon. This is distinct from classical models and other field-scale measurements of turbidity currents. The slow-moving body is dominated by suspended fine-grained sediment. The body mixes with the surrounding fluid leaving diffuse clouds of sediment that persist for days after initial entrainment. Ambient tidal flow also controls the mixing within the body and the surrounding fluid. Our results provide a new quantification of suspended sediment within flows and the interaction with the surrounding fluid.

  4. Glow-to-arc transition events in H2-Ar direct current pulsed plasma: Automated measurement of current and voltage

    Mendes, Luciano A.; Rodrigues, Jhonatam C.; Mafra, Marcio

    2012-01-01

    The glow-to-arc transition phenomena (arcing) observed in plasma reactors used in materials processing was studied through the arcs characteristic current and voltage waveforms. In order to capture these arcs signals, a LABVIEW based automated instrumentation system (ARCVIEW) was developed, including the integration of an oscilloscope equipped with proper current and voltage probes. The system also allows capturing the process parameters at the arc occurrence moments, which were used to map the arcs events conditions. Experiments in H 2 -Ar DC pulsed plasma returned signals data from 215 arcs events, which were analyzed through software routines. According to the results, an anti-arcing system should react in the time order of few microseconds to prevent most of the damage caused by the undesired arcing phenomena.

  5. Fire metrology: Current and future directions in physics-based measurements

    Robert L. Kremens; Alistair M.S. Smith; Matthew B. Dickinson

    2010-01-01

    The robust evaluation of fire impacts on the biota, soil, and atmosphere requires measurement and analysis methods that can characterize combustion processes across a range of temporal and spatial scales. Numerous challenges are apparent in the literature. These challenges have led to novel research to quantify the 1) structure and heterogeneity of the pre-fire...

  6. Atmospheric Radiation Measurement Program Science Plan. Current Status and Future Directions of the ARM Science Program

    Ackerman, Thomas P.; Del Genio, Anthony D.; Ellingson, Robert G.; Ferrare, Richard A.; Klein, Steve A.; McFarquhar, Gregory M.; Lamb, Peter J.; Long, Charles M.; Verlinde, Johannes

    2004-10-30

    The Atmospheric Radiation Measurement (ARM) Program has matured into one of the key programs in the U.S. Climate Change Science Program. The ARM Program has achieved considerable scientific success in a broad range of activities, including site and instrument development, atmospheric radiative transfer, aerosol science, determination of cloud properties, cloud modeling, and cloud parameterization testing and development. The focus of ARM science has naturally shifted during the last few years to an increasing emphasis on modeling and parameterization studies to take advantage of the long time series of data now available. During the next 5 years, the principal focus of the ARM science program will be to: Maintain the data record at the fixed ARM sites for at least the next five years; Improve significantly our understanding of and ability to parameterize the 3-D cloud-radiation problem at scales from the local atmospheric column to the global climate model (GCM) grid square; Continue developing techniques to retrieve the properties of all clouds, with a special focus on ice clouds and mixed-phase clouds; Develop a focused research effort on the indirect aerosol problem that spans observations, physical models, and climate model parameterizations; Implement and evaluate an operational methodology to calculate broad-band heating rates in the atmospheric columns at the ARM sites; Develop and implement methodologies to use ARM data more effectively to test atmospheric models, both at the cloud-resolving model scale and the GCM scale; and, Use these methodologies to diagnose cloud parameterization performance and then refine these parameterizations to improve the accuracy of climate model simulations. In addition, the ARM Program is actively developing a new ARM Mobile Facility (AMF) that will be available for short deployments (several months to a year or more) in climatically important regions. The AMF will have much of the same instrumentation as the remote

  7. Current Direct Neutrino Mass Experiments

    G. Drexlin

    2013-01-01

    Full Text Available In this contribution, we review the status and perspectives of direct neutrino mass experiments, which investigate the kinematics of β-decays of specific isotopes (3H, 187Re, 163Ho to derive model-independent information on the averaged electron (antineutrino mass. After discussing the kinematics of β-decay and the determination of the neutrino mass, we give a brief overview of past neutrino mass measurements (SN1987a-ToF studies, Mainz and Troitsk experiments for 3H, cryobolometers for 187Re. We then describe the Karlsruhe Tritium Neutrino (KATRIN experiment currently under construction at Karlsruhe Institute of Technology, which will use the MAC-E-Filter principle to push the sensitivity down to a value of 200 meV (90% C.L.. To do so, many technological challenges have to be solved related to source intensity and stability, as well as precision energy analysis and low background rate close to the kinematic endpoint of tritium β-decay at 18.6 keV. We then review new approaches such as the MARE, ECHO, and Project8 experiments, which offer the promise to perform an independent measurement of the neutrino mass in the sub-eV region. Altogether, the novel methods developed in direct neutrino mass experiments will provide vital information on the absolute mass scale of neutrinos.

  8. EOP Current Magnitude and Direction

    National Oceanic and Atmospheric Administration, Department of Commerce — These data contain shipboard current magnitudes and directions collected in the Pacific, both pelagic and near shore environments. Data is collected using an RD...

  9. Prediction of liquid metal alloy radiant properties from measurements of the Hall coefficient and the direct current resistivity

    Havstad, M.A.; Qiu, T.

    1995-04-01

    The thermal radiative properties of high temperature solid and liquid metal alloys are particularly useful to research and development efforts in laser cladding and machining, electron beam welding and laser isotope separation. However the cost, complexity, and difficulty of measuring these properties have forced the use of crude estimates from the Hagen-Rubens relation, the Drude relations, or extrapolation from low temperature or otherwise flawed data (e.g., oxidized). The authors have found in this work that published values for the Hall coefficient and the electrical resistivity of liquid metal alloys can provide useful estimates of the reflectance and emittance of some groups of binary liquid metal and high temperature solid alloys. The estimation method computes the Drude free electron parameters, and thence the optical constants and the radiant properties from the dependence of the Hall coefficient and direct current resistivity on alloy composition (the Hall coefficient gives the free electron density and the resistivity gives the average time between collisions). They find that predictions of the radiant properties of molten cerium-copper alloy, which use the measured variations in the Hall coefficient and resistivity (both highly nonlinear) as a function of alloy fraction (rather than linear combinations of the values of the pure elements) yield a good comparison to published measurements of the variation of the normal spectral emittance (a different but also nonlinear function) of cerium-copper alloy at the single wavelength available for comparison, 0.645 μm. The success of the approach in the visible range is particularly notable because one expects a Drude based approach to improve with increasing wavelength from the visible into the infrared. Details of the estimation method, the comparison between the calculation and the measured emittance, and a discussion of what groups of elements may also provide agreement is given

  10. The development of crack measurement system using the direct current potential drop method for use in the hot cell

    Kim, Do-Sik; Ahn, Sang-Bok; Lee, Key-Soon; Kim, Yong-Suk; Kwon, Sang-Chul

    1999-01-01

    The crack length measurement system using the direct current potential drop (DCPD) method was developed for the detection of crack growth initiation and subsequent crack growth. The experimental precautions and data processing procedure required for its application were also described find discussed. The system presented herein was specially built for use in fracture toughness testing of unirradiated or irradiated pressure tube materials from nuclear reactor. The application of this system for fracture toughness determination was illustrated from the test of curved compact tension specimens removed from CANDU reactor pressure tubes. The crack extension was monitored using the DCPD method. It is found that the changes of the potential drop and the changes of the crack length have a linear relationship. The final crack front was marked by heat-tinting after the test and the specimen broken open for determination of the initial and final physical crack length. The physical crack lengths, obtained by the 9-point average method described in ASTM E1737-96 on heat-tinted fracture surface, were used to calibrate the DCPD method for each test on an individual basis by matching the change in voltage to the crack extension. It is found that this system can be recommended for determination of the J-integral resistance (J-R) curve of unirradiated or irradiation materials in the hot cell, especially when testing at elevated temperature and in the environment chamber or furnace. (author)

  11. Dispersion and current measurements

    Boelskifte, S.

    1986-04-01

    A model for the simulation of particle movements in water should incorporate the mutual distance dependent correlation. As long as reliable data are given accessible a model can be created of the dispersion in a given area from a statistical description of turbulence. Current measurements have been performed in an area north of the Swedish nuclear power plant Barsebaeck, and statistical time series analysis have made it possible to estimate multivariate autoregressive moving-average (ARMA) models for these data using the Box-Jenkins method. The correlation structure for the area has been investigated in detail. Transport and dispersion models for the marine environment are used in estimating doses to the population from the aquatic food chain. Some of these models are described with special emphasis on the time and length scales they cover. Furthermore, to illustrate the background of the simulation model, short introductuions are given to health physics, time series analysis, and turbulence theory. Analysis of the simulation model shows the relative importance of the different parameters. The model can be expanded to conditional simulation, where the current measurements are used directly to simulate the movement of one of the particles. Results from the model are also compared to results from a sampling of bioindicators (Fucus vesiculosus) along the Danish coast. The reliability of bioindicators in this kind of experiment is discussed. (author)

  12. Transcranial direct current stimulation reduces food-craving and measures of hyperphagia behavior in participants with Prader-Willi syndrome.

    Bravo, Gabriela L; Poje, Albert B; Perissinotti, Iago; Marcondes, Bianca F; Villamar, Mauricio F; Manzardo, Ann M; Luque, Laura; LePage, Jean F; Stafford, Diane; Fregni, Felipe; Butler, Merlin G

    2016-03-01

    Prader-Willi syndrome (PWS) is a neurodevelopmental genetic disorder characterized by intellectual disabilities and insatiable appetite with compulsive eating leading to severe obesity with detrimental health consequences. Transcranial direct current stimulation (tDCS) has been shown to modulate decision-making and cue-induced food craving in healthy adults. We conducted a pilot double blind, sham-controlled, multicenter study of tDCS modulation of food drive and craving in 10 adult PWS participants, 11 adult obese (OB) and 11 adult healthy-weight control (HWC) subjects. PWS and OB subjects received five consecutive daily sessions of active or sham tDCS over the right dorsolateral prefrontal cortex (DLPFC), while HWC received a single sham and active tDCS in a crossover design. Standardized psychometric instruments assessed food craving, drive and hyperphagia by self-report and caregiver assessment over 30 days. Robust baseline differences were observed in severity scores for the Three-Factor Eating Questionnaire (TFEQ) and Dykens Hyperphagia Questionnaire (DHQ) for PWS compared to HWC while obese participants were more similar to HWC. Active tDCS stimulation in PWS was associated with a significant change from baseline in TFEQ Disinhibition (Factor II) (Ƶ = 1.9, P food drive and behaviors impacting hyperphagia in PWS. Transcranial direct current stimulation may represent a straight-forward, low risk and low cost method to improve care, management and quality of life in PWS. © 2015 Wiley Periodicals, Inc.

  13. Direct neutrino mass measurements

    Weinheimer, Christian, E-mail: weinheimer@uni-muenster.de [Westfaelische Wilhelms-Universitaet, Institut fuer Kernphysik (Germany)

    2013-03-15

    Direct neutrino mass experiments are complementary to searches for neutrinoless double {beta}-decay and to analyses of cosmological data. The previous tritium beta decay experiments at Mainz and at Troitsk have achieved upper limits on the neutrino mass of about 2 eV/c{sup 2} . The KATRIN experiment under construction will improve the neutrino mass sensitivity down to 200 meV/c{sup 2} by increasing strongly the statistics and-at the same time-reducing the systematic uncertainties. Huge improvements have been made to operate the system extremely stably and at very low background rate. The latter comprises new methods to reject secondary electrons from the walls as well as to avoid and to eject electrons stored in traps. As an alternative to tritium {beta}-decay experiments cryo-bolometers investigating the endpoint region of {sup 187}Re {beta}-decay or the electron capture of {sup 163}Ho are being developed. This article briefly reviews the current status of the direct neutrino mass measurements.

  14. Current directions in radiopharmaceutical research

    Mather, S J [Department of Nuclear Medicine, St. Bartholomew` s Hospital, London (United Kingdom)

    1998-08-01

    Much of current radiopharmaceutical research is directed towards the development of receptor-binding tracers which are targeted towards biochemical processes. These may be extra or intracellular in nature and hold promise for an imaging approach to tissue characterisation in-vivo. Many of these products are based on proteins which range in size from large monoclonal antibodies to small neuropeptides and share a radiolabelling chemistry based on the use of bifunctional chelating agents. Although developed initially for use with indium-111, considerations of cost and isotope availability have continued to direct the efforts of many researchers towards the use of technetium-99m. While polypeptide-based radiopharmaceuticals may be useful for imaging peripheral cell-surface receptors, access to sites of interest within the cell, or in the brain, requires the development of small lipophilic molecules with retained ability to interact with intracellular targets. The design and synthesis of these compounds presents a particular challenge to the radiopharmaceutical chemist which is being met through either a pendant or integrated approach to the use of technetium coordination with particular emphasis on technetium (v) cores. Progress continues to be made in the application of targeted radionuclide therapy particularly in the development of radiopharmaceuticals for the treatment of malignant bone disease. methods for labelling antibodies with a great variety of cytotoxic radionuclides have now been refined and their use for radioimmunotherapy in the treatment of haematological malignancies shows great promise. The major medical areas for application of these new radiopharmaceuticals will be in oncology, neurology and inflammation but the increasingly difficult regulatory climate in which drug development and health-care now operate will make it essential for researchers to direct their products toward specific clinical problems as well as biological targets. (author) 36 refs

  15. Current directions in radiopharmaceutical research

    Mather, S.J.

    1998-01-01

    Much of current radiopharmaceutical research is directed towards the development of receptor-binding tracers which are targeted towards biochemical processes. These may be extra or intracellular in nature and hold promise for an imaging approach to tissue characterisation in-vivo. Many of these products are based on proteins which range in size from large monoclonal antibodies to small neuropeptides and share a radiolabelling chemistry based on the use of bifunctional chelating agents. Although developed initially for use with indium-111, considerations of cost and isotope availability have continued to direct the efforts of many researchers towards the use of technetium-99m. While polypeptide-based radiopharmaceuticals may be useful for imaging peripheral cell-surface receptors, access to sites of interest within the cell, or in the brain, requires the development of small lipophilic molecules with retained ability to interact with intracellular targets. The design and synthesis of these compounds presents a particular challenge to the radiopharmaceutical chemist which is being met through either a pendant or integrated approach to the use of technetium coordination with particular emphasis on technetium (v) cores. Progress continues to be made in the application of targeted radionuclide therapy particularly in the development of radiopharmaceuticals for the treatment of malignant bone disease. methods for labelling antibodies with a great variety of cytotoxic radionuclides have now been refined and their use for radioimmunotherapy in the treatment of haematological malignancies shows great promise. The major medical areas for application of these new radiopharmaceuticals will be in oncology, neurology and inflammation but the increasingly difficult regulatory climate in which drug development and health-care now operate will make it essential for researchers to direct their products toward specific clinical problems as well as biological targets. (author)

  16. Evaluating the Global Precipitation Measurement mission with NOAA/NSSL Multi-Radar Multisensor: current status and future directions.

    Kirstetter, P. E.; Petersen, W. A.; Gourley, J. J.; Kummerow, C.; Huffman, G. J.; Turk, J.; Tanelli, S.; Maggioni, V.; Anagnostou, E. N.; Hong, Y.; Schwaller, M.

    2017-12-01

    Accurate characterization of uncertainties in space-borne precipitation estimates is critical for many applications including water budget studies or prediction of natural hazards at the global scale. The GPM precipitation Level II (active and passive) and Level III (IMERG) estimates are compared to the high quality and high resolution NEXRAD-based precipitation estimates derived from the NOAA/NSSL's Multi-Radar, Multi-Sensor (MRMS) platform. A surface reference is derived from the MRMS suite of products to be accurate with known uncertainty bounds and measured at a resolution below the pixel sizes of any GPM estimate, providing great flexibility in matching to grid scales or footprints. It provides an independent and consistent reference research framework for directly evaluating GPM precipitation products across a large number of meteorological regimes as a function of resolution, accuracy and sample size. The consistency of the ground and space-based sensors in term of precipitation detection, typology and quantification are systematically evaluated. Satellite precipitation retrievals are further investigated in terms of precipitation distributions, systematic biases and random errors, influence of precipitation sub-pixel variability and comparison between satellite products. Prognostic analysis directly provides feedback to algorithm developers on how to improve the satellite estimates. Specific factors for passive (e.g. surface conditions for GMI) and active (e.g. non uniform beam filling for DPR) sensors are investigated. This cross products characterization acts as a bridge to intercalibrate microwave measurements from the GPM constellation satellites and propagate to the combined and global precipitation estimates. Precipitation features previously used to analyze Level II satellite estimates under various precipitation processes are now intoduced for Level III to test several assumptions in the IMERG algorithm. Specifically, the contribution of Level II is

  17. Adjustable direct current and pulsed circuit fault current limiter

    Boenig, Heinrich J.; Schillig, Josef B.

    2003-09-23

    A fault current limiting system for direct current circuits and for pulsed power circuit. In the circuits, a current source biases a diode that is in series with the circuits' transmission line. If fault current in a circuit exceeds current from the current source biasing the diode open, the diode will cease conducting and route the fault current through the current source and an inductor. This limits the rate of rise and the peak value of the fault current.

  18. Current status and future directions of nuclear education in elementary and secondary education. Several measures for revitalization

    Hirose, Masami; Tsuruta, Takao; Shibata, Toshikazu

    1999-01-01

    It has been a long time since a necessity to deepen education concerning energy, in particular, nuclear-related education in the elementary and secondary education curriculums in Japan was pointed out. To attain this objective, the nuclear industry and the education industry should work in close cooperation. As the Ministry of Education's Course of Study substantially regulates the direction of school education in Japan, nuclear energy experts should be involved in its development from an early stage in an appropriate manner. At least, training for the teaching profession for science teachers should include experiments related to nuclear energy and radiation. It is considered quite effective to provide incumbent teachers with various training opportunities by nuclear organizations in order to solve the problem in question. (author)

  19. Current Directions in Mediation Analysis

    MacKinnon, David P.; Fairchild, Amanda J.

    2010-01-01

    Mediating variables continue to play an important role in psychological theory and research. A mediating variable transmits the effect of an antecedent variable on to a dependent variable, thereby providing more detailed understanding of relations among variables. Methods to assess mediation have been an active area of research for the last two decades. This paper describes the current state of methods to investigate mediating variables. PMID:20157637

  20. Current Directions in Mediation Analysis

    MacKinnon, David P.; Fairchild, Amanda J.

    2009-01-01

    Mediating variables continue to play an important role in psychological theory and research. A mediating variable transmits the effect of an antecedent variable on to a dependent variable, thereby providing more detailed understanding of relations among variables. Methods to assess mediation have been an active area of research for the last two decades. This paper describes the current state of methods to investigate mediating variables.

  1. Development and Application of a Wireless Sensor for Space Charge Density Measurement in an Ultra-High-Voltage, Direct-Current Environment.

    Xin, Encheng; Ju, Yong; Yuan, Haiwen

    2016-10-20

    A space charge density wireless measurement system based on the idea of distributed measurement is proposed for collecting and monitoring the space charge density in an ultra-high-voltage direct-current (UHVDC) environment. The proposed system architecture is composed of a number of wireless nodes connected with space charge density sensors and a base station. The space charge density sensor based on atmospheric ion counter method is elaborated and developed, and the ARM microprocessor and Zigbee radio frequency module are applied. The wireless network communication quality and the relationship between energy consumption and transmission distance in the complicated electromagnetic environment is tested. Based on the experimental results, the proposed measurement system demonstrates that it can adapt to the complex electromagnetic environment under the UHVDC transmission lines and can accurately measure the space charge density.

  2. Object Detection: Current and Future Directions

    Rodrigo eVerschae

    2015-11-01

    Full Text Available Object detection is a key ability required by most computer and robot vision systems. The latest research on this area has been making great progress in many directions. In the current manuscript we give an overview of past research on object detection, outline the current main research directions, and discuss open problems and possible future directions.

  3. Navy Telemedicine: Current Research and Future Directions

    Reed, Cheryl

    2002-01-01

    .... This report reviews military and civilian models for evaluating telemedicine systems in order to determine future directions for Navy telemedicine research within the current funding environment...

  4. Assisted extraction of the energy level spacings and lever arms in direct current bias measurements of one-dimensional quantum wires, using an image recognition routine

    Lesage, A. A. J.; Smith, L. W.; Griffiths, J. P.; Farrer, I.; Jones, G. A. C.; Ritchie, D. A.; Smith, C. G.; Al-Taie, H.; Kelly, M. J.; See, P.

    2015-01-01

    A multiplexer technique is used to individually measure an array of 256 split gates on a single GaAs/AlGaAs heterostructure. This results in the generation of large volumes of data, which requires the development of automated data analysis routines. An algorithm is developed to find the spacing between discrete energy levels, which form due to transverse confinement from the split gate. The lever arm, which relates split gate voltage to energy, is also found from the measured data. This reduces the time spent on the analysis. Comparison with estimates obtained visually shows that the algorithm returns reliable results for subband spacing of split gates measured at 1.4 K. The routine is also used to assess direct current bias spectroscopy measurements at lower temperatures (50 mK). This technique is versatile and can be extended to other types of measurements. For example, it is used to extract the magnetic field at which Zeeman-split 1D subbands cross one another

  5. Stability analysis of direct current control in current source rectifier

    Lu, Dapeng; Wang, Xiongfei; Blaabjerg, Frede

    2017-01-01

    Current source rectifier with high switching frequency has a great potential for improving the power efficiency and power density in ac-dc power conversion. This paper analyzes the stability of direct current control based on the time delay effect. Small signal model including dynamic behaviors...

  6. A three-port direct current converter

    2016-01-01

    circuit comprises a connection between the at least one input direct current source and the at least one storage battery, the primary side circuit configured for operating as a buck converter; a second magnetic component serially coupled to the first single magnetic component, wherein the first and second...... magnetic components are configured to perform a voltage step-up, wherein the secondary side circuit comprises a connection between the at least one storage battery and at least one load, the secondary side configured for operating as a tapped boost converter; wherein the three-port direct current converter......The three-port direct current converter comprising: at least one input direct current source; at least one storage battery; a primary side circuit; a secondary side circuit; a first single magnetic component shared by the primary side circuit and the secondary side circuit, wherein the primary side...

  7. HIV vaccines: current challenges and future directions.

    Avrett, Sam; Collins, Chris

    2002-07-01

    Volume seven of the Review will mark the tenth anniversary of the Canadian HIV/AIDS Legal Network with a series of articles that describe past developments and future directions in several areas of policy and law related to HIV/AIDS. The following article is the first of these, discussing current challenges and future directions in the development of and access to HIV vaccines. It argues that governments are under public health, ethical, and legal obligations to develop and provide access to HIV vaccines. It further explains what is required for governments to fulfill their obligations: additional commitment and resources for HIV vaccine development in the context of increased global research and development regarding diseases of the poor; increased support and advocacy for partnerships to develop HIV vaccines; enhanced regulatory capacity in every country to review, approve, and monitor HIV vaccines; and assurance of global supply of, procurement of, delivery of, and access to vaccines in the context of efforts to increase global access to public health measures and technologies.

  8. Directional wave measurements and modelling

    Anand, N.M.; Nayak, B.U.; Bhat, S.S.; SanilKumar, V.

    Some of the results obtained from analysis of the monsoon directional wave data measured over 4 years in shallow waters off the west coast of India are presented. The directional spectrum computed from the time series data seems to indicate...

  9. Anodal Transcranial Direct Current Stimulation Shows Minimal, Measure-Specific Effects on Dynamic Postural Control in Young and Older Adults: A Double Blind, Sham-Controlled Study.

    Craig, Chesney E; Doumas, Michail

    2017-01-01

    We investigated whether stimulating the cerebellum and primary motor cortex (M1) using transcranial direct current stimulation (tDCS) could affect postural control in young and older adults. tDCS was employed using a double-blind, sham-controlled design, in which young (aged 18-35) and older adults (aged 65+) were assessed over three sessions, one for each stimulatory condition-M1, cerebellar and sham. The effect of tDCS on postural control was assessed using a sway-referencing paradigm, which induced platform rotations in proportion to the participant's body sway, thus assessing sensory reweighting processes. Task difficulty was manipulated so that young adults experienced a support surface that was twice as compliant as that of older adults, in order to minimise baseline age differences in postural sway. Effects of tDCS on postural control were assessed during, immediately after and 30 minutes after tDCS. Additionally, the effect of tDCS on corticospinal excitability was measured by evaluating motor evoked potentials using transcranial magnetic stimulation immediately after and 30 minutes after tDCS. Minimal effects of tDCS on postural control were found in the eyes open condition only, and this was dependent on the measure assessed and age group. For young adults, stimulation had only offline effects, as cerebellar stimulation showed higher mean power frequency (MPF) of sway 30 minutes after stimulation. For older adults, both stimulation conditions delayed the increase in sway amplitude witnessed between blocks one and two until stimulation was no longer active. In conclusion, despite tDCS' growing popularity, we would caution researchers to consider carefully the type of measures assessed and the groups targeted in tDCS studies of postural control.

  10. Resistivity measurements using a direct current induction method (1963); Mesure de resistivite par la methode d'induction en courant continu (1963)

    Delaplace, J; Hillairet, J [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1964-07-01

    The conventional methods for measuring electrical resistivities necessitate the fixing of electrical contacts on the sample either mechanically or by soldering. Furthermore it is also necessary to carry,out the measurements on low cross-section samples which are not always easy to obtain. Our direct-current induction method on the other hand requires no contacts and can easily be applied to samples of large cross-section. The sample is placed in a uniform magnetic field; at the moment when the current is cut, eddy currents appear in the sample which tend to oppose the disappearance of the field. The way in which the magnetic flux decreases in the sample makes it possible to determine the resistivity of the material. This method has been applied to samples having diameters of between 1 and 30 mm in the case of metals which are good conductors. It gives a value for the local resistivity and makes it possible to detect any variation along a sample. The measurements can be carried out at all temperature from a few degrees absolute to 500 deg. C. We have used the induction method to follow the purification of beryllium by zone-melting; it is in effect possible to estimate the purity of a material by resistivity measurements. We have measured the resistivity along each bar treated by the zone-melting technique and have thus, localised the purest section. High temperature measurements have been carried out on uranium carbide and on iron-aluminium alloys. This method constitutes an interesting means of investigation the resistivity of solid materials. Its accuracy and rapidity make it particularly adapted both to fundamental research and to production control. (authors) [French] Les methodes classiques de mesure de resistivite electrique imposent la realisation sur l'echantillon de contacts electriques obtenus soit mecaniquement, soit par soudure. En outre, elles demandent, le plus souvent, d'effectuer les mesures sur des echantillons de faible section qu'il n'est pas

  11. Navy Telemedicine: Current Research and Future Directions

    Reed, Cheryl

    2002-01-01

    .... An assessment of Navy telemedicine as a complex healthcare support system is needed to demonstrate how current practices, training, equipment, and expenditures measure up to the emerging needs of the Fleet...

  12. Direct current power delivery system and method

    Zhang, Di; Garces, Luis Jose; Dai, Jian; Lai, Rixin

    2016-09-06

    A power transmission system includes a first unit for carrying out the steps of receiving high voltage direct current (HVDC) power from an HVDC power line, generating an alternating current (AC) component indicative of a status of the first unit, and adding the AC component to the HVDC power line. Further, the power transmission system includes a second unit for carrying out the steps of generating a direct current (DC) voltage to transfer the HVDC power on the HVDC power line, wherein the HVDC power line is coupled between the first unit and the second unit, detecting a presence or an absence of the added AC component in the HVDC power line, and determining the status of the first unit based on the added AC component.

  13. Reversal thyristor-relay direct current commutator

    Ivanenko, A.I.

    1982-01-01

    A thyristor-relay commutator used for alteration of the leading magnetic field direction in experiments with polarized neutrons is described. The commutator flowsheet is presented. Thyristors, connected so as to allow the relay trigger operation mode, are used as controllable electronic relay. Two connected in series coils with the total inductance of the order of 0.28 H serve as the electronic relay load. The arc-free current commutation is effected at the moment of the minimal current across the load terminals, which allows to easily reverse the current up to 10 A at a volatage, v <= 150 V. The experience gained within a year of operation has shown that the commutator meets the requirements of reliability and tuning

  14. Direct current contamination of kilohertz frequency alternating current waveforms.

    Franke, Manfred; Bhadra, Niloy; Bhadra, Narendra; Kilgore, Kevin

    2014-07-30

    Kilohertz frequency alternating current (KHFAC) waveforms are being evaluated in a variety of physiological settings because of their potential to modulate neural activity uniquely when compared to frequencies in the sub-kilohertz range. However, the use of waveforms in this frequency range presents some unique challenges regarding the generator output. In this study we explored the possibility of undesirable contamination of the KHFAC waveforms by direct current (DC). We evaluated current- and voltage-controlled KHFAC waveform generators in configurations that included a capacitive coupling between generator and electrode, a resistive coupling and combinations of capacitive with inductive coupling. Our results demonstrate that both voltage- and current-controlled signal generators can unintentionally add DC-contamination to a KHFAC signal, and that capacitive coupling is not always sufficient to eliminate this contamination. We furthermore demonstrated that high value inductors, placed in parallel with the electrode, can be effective in eliminating DC-contamination irrespective of the type of stimulator, reducing the DC contamination to less than 1 μA. This study highlights the importance of carefully designing the electronic setup used in KHFAC studies and suggests specific testing that should be performed and reported in all studies that assess the neural response to KHFAC waveforms. Published by Elsevier B.V.

  15. Transcranial Direct Current Stimulation in Epilepsy.

    San-Juan, Daniel; Morales-Quezada, León; Orozco Garduño, Adolfo Josué; Alonso-Vanegas, Mario; González-Aragón, Maricarmen Fernández; Espinoza López, Dulce Anabel; Vázquez Gregorio, Rafael; Anschel, David J; Fregni, Felipe

    2015-01-01

    Transcranial direct current stimulation (tDCS) is an emerging non-invasive neuromodulation therapy in epilepsy with conflicting results in terms of efficacy and safety. Review the literature about the efficacy and safety of tDCS in epilepsy in humans and animals. We searched studies in PubMed, MedLine, Scopus, Web of Science and Google Scholar (January 1969 to October 2013) using the keywords 'transcranial direct current stimulation' or 'tDCS' or 'brain polarization' or 'galvanic stimulation' and 'epilepsy' in animals and humans. Original articles that reported tDCS safety and efficacy in epileptic animals or humans were included. Four review authors independently selected the studies, extracted data and assessed the methodological quality of the studies using the recommendations of the Cochrane Handbook for Systematic Reviews of Interventions, PRISMA guidelines and Jadad Scale. A meta-analysis was not possible due to methodological, clinical and statistical heterogeneity of included studies. We analyzed 9 articles with different methodologies (3 animals/6 humans) with a total of 174 stimulated individuals; 109 animals and 65 humans. In vivo and in vitro animal studies showed that direct current stimulation can successfully induce suppression of epileptiform activity without neurological injury and 4/6 (67%) clinical studies showed an effective decrease in epileptic seizures and 5/6 (83%) reduction of inter-ictal epileptiform activity. All patients tolerated tDCS well. tDCS trials have demonstrated preliminary safety and efficacy in animals and patients with epilepsy. Further larger studies are needed to define the best stimulation protocols and long-term follow-up. Copyright © 2015 Elsevier Inc. All rights reserved.

  16. LANMAS core: Update and current directions

    Claborn, J.

    1995-01-01

    Local Area Network Material Accountability system (LANMAS) core software provides the framework of a material accountability system. It tracks the movement of material throughout a site and generates the required material accountability reports. LANMAS is a net-work- based nuclear material accountability system that runs in a client/server mode. The database of material type and location resides on the server, while the user interface runs on the client. The user interface accesses the data stored on the server via a network. The LANMAS core can be used as the foundation for building required materials control and accountability (MCA) functionality at any site requiring a new MCA system. An individual site will build on the LANMAS core by supplying site-specific software. This paper will provide an update on the current LANMAS development activities and discuss the current direction of the LANMAS project

  17. Brainstem tumors: Current management and future directions

    Pablo F Recinos

    2012-01-01

    Full Text Available Tumors arising in the brainstem comprise 10-20% of all pediatric central nervous system (CNS tumors and account for a small percentage in adults. The prognosis for these tumors was considered uniformly poor prior to the era of modern neuroimaging and the location was fraught with disaster being considered a ′no man′s land′ for neurosurgeons. Following the introduction of advanced imaging modalities and neurophysiological monitoring, striking progress has occurred in the management of these lesions. Brainstem tumors are presently classified based on their anatomic location, focality, and histopathology. This article reviews the current classification of brainstem tumors, current management options, and future directions in the treatment for these rare tumors.

  18. Obesity pharmacotherapy: current perspectives and future directions.

    Misra, Monika

    2013-02-01

    The rising tide of obesity and its related disorders is one of the most pressing health concerns worldwide, yet existing medicines to combat the problem are disappointingly limited in number and effectiveness. Recent advances in mechanistic insights into the neuroendocrine regulation of body weight have revealed an expanding list of molecular targets for novel, rationally designed antiobesity pharmaceutical agents. Antiobesity drugs act via any of four mechanisms: 1) decreasing energy intake, 2) increasing energy expenditure or modulating lipid metabolism, 3) modulating fat stores or adipocyte differentiation, and 4) mimicking caloric restriction. Various novel drug candidates and targets directed against obesity are currently being explored. A few of them are also in the later phases of clinical trials. This review discusses the development of novel antiobesity drugs based on current understanding of energy homeostasis.

  19. [The risk of direct current countershock].

    Gajek, J; Zyśko, D

    2001-07-01

    Direct current cardioversion (DCC) is a procedure commonly used to restore the sinus rhythm in patients with supraventricular and ventricular arrhythmias. Its safety, regarding the use of electric current, is still a matter of controversy and debate. The patients with atrial fibrillation/flutter, supraventricular or ventricular tachycardia represent a broad spectrum of clinical conditions and it is difficult to draw the conclusions. The high success rate of DCC in restoring the sinus rhythm, may be partly responsible for enhancing and revealing proarrhythmic properties of antiarrhythmic drugs. The deaths described as a complications of DCC were mainly due to the proarrhythmia and less common to the progression of the pathologic process. The embolic, arrhythmic and anesthetic complications of DCC can be prevented if the known recommendations of performing the DCC are followed. The authors review critically the literature data about the complications of the procedure and come to the conclusion of safety of DCC.

  20. LANMAS core: Update and current directions

    Claborn, J.

    1994-01-01

    Local Area Network Material Accountability System (LANMAS) core software will provide the framework of a material accountability system. LANMAS is a network-based nuclear material accountability system. It tracks the movement of material throughout a site and generates the required reports on material accountability. LANMAS will run in a client/server mode. The database of material type and location will reside on the server, while the user interface runs on the client. The user interface accesses the server via a network. The LANMAS core can be used as the foundation for building required Materials Control and Accountability (MC ampersand A) functionality at any site requiring a new MC ampersand A system. An individual site will build on the LANMAS core by supplying site-specific software. This paper will provide an update on the current LANMAS development activities and discuss the current direction of the LANMAS project

  1. FMIT direct-current beam monitor

    Brousseau, A.T.; Chamberlin, D.D.

    1981-01-01

    The prototype injector section for the Fusion Materials Irradiation Test (FMIT) Facility being developed at the Los Alamos National Laboratory requires that beam parameters be noninterceptively monitored. This report describes the application of a single toroidal core, coupled with very simple circuitry, that results in the production of a simple instrument, and eliminates the problems inherent in the Faraday cup technique for the current measurements of the FMIT injector beam

  2. Directed information measures in neuroscience

    Vicente, Raul; Lizier, Joseph

    2014-01-01

    Analysis of information transfer has found rapid adoption in neuroscience, where a highly dynamic transfer of information continuously runs on top of the brain's slowly-changing anatomical connectivity. Measuring such transfer is crucial to understanding how flexible information routing and processing give rise to higher cognitive function. Directed Information Measures in Neuroscience reviews recent developments of concepts and tools for measuring information transfer, their application to neurophysiological recordings and analysis of interactions. Written by the most active researchers in the field the book discusses the state of the art, future prospects and challenges on the way to an efficient assessment of neuronal information transfer. Highlights include the theoretical quantification and practical estimation of information transfer, description of transfer locally in space and time, multivariate directed measures, information decomposition among a set of stimulus/responses variables, and the relation ...

  3. Direct current hopping conductance along DNA chain

    Ma Song-Shan; Xu Hui; Liu Xiao-Liang; Li Ming-Jun

    2007-01-01

    This paper proposes a model of direct current(DC) electron hopping transport in DNA,in which DNA is considered as a binary one-dimensional disordered system.To quantitatively study the DC conductivity in DNA,it numerically calculates the DC conductivity of DNA chains with difierent parameter values.The result shows that the DC conductivity of DNA chain increases with the increase of temperature.And the conductivity of DNA chain is depended on the probability P.which represents the degree of compositional disorder in a DNA sequence to some extent.For P<0.5,the conductivity of DNA chain decreases with the increase of P,while for P≥0.5,the conductivity increases with the increase of p.The DC conductivity in DNA chain also varies with the change of the electric field,it presents non-Ohm's law conductivity characteristics.

  4. Dark Current Measurements in GIF++

    Al-Qahtani, Abdulaziz

    2017-01-01

    This project revolved around creating a code that treats experiment files in order to fetch dark current measurements done for the Cathode Strip Chambers (CSC) exposed to long-term irradiation at Gamma Irradiation Facility (GIF++) and plot the results as functions of the accumulated charge. This paper will discuss the Compact Muon Solenoid (CMS) experiment, the CSCs that we have looked at (specifically the muon detectors located at the CMS endcaps), longevity test at GIF++, and finally discuss the code and results obtained.

  5. Understanding S-shaped current-voltage characteristics of organic solar cells: Direct measurement of potential distributions by scanning Kelvin probe

    Saive, Rebecca; Mueller, Christian; Schinke, Janusz; Lovrincic, Robert; Kowalsky, Wolfgang

    2013-12-01

    We present a comparison of the potential distribution along the cross section of bilayer poly(3-hexylthiophene)/1-(3-methoxycarbonyl)propyl-1-phenyl[6,6]C61 (P3HT/PCBM) solar cells, which show normal and anomalous, S-shaped current-voltage (IV) characteristics. We expose the cross sections of the devices with a focussed ion beam and measure them with scanning Kelvin probe microscopy. We find that in the case of S-shaped IV-characteristics, there is a huge potential drop at the PCBM/Al top contact, which does not occur in solar cells with normal IV-characteristics. This behavior confirms the assumption that S-shaped curves are caused by hindered charge transport at interfaces.

  6. Understanding S-shaped current-voltage characteristics of organic solar cells: Direct measurement of potential distributions by scanning Kelvin probe

    Saive, Rebecca; Kowalsky, Wolfgang; Mueller, Christian; Schinke, Janusz; Lovrincic, Robert

    2013-01-01

    We present a comparison of the potential distribution along the cross section of bilayer poly(3-hexylthiophene)/1-(3-methoxycarbonyl)propyl-1-phenyl[6,6]C61 (P3HT/PCBM) solar cells, which show normal and anomalous, S-shaped current-voltage (IV) characteristics. We expose the cross sections of the devices with a focussed ion beam and measure them with scanning Kelvin probe microscopy. We find that in the case of S-shaped IV-characteristics, there is a huge potential drop at the PCBM/Al top contact, which does not occur in solar cells with normal IV-characteristics. This behavior confirms the assumption that S-shaped curves are caused by hindered charge transport at interfaces

  7. Virtual Inertia: Current Trends and Future Directions

    Ujjwol Tamrakar

    2017-06-01

    Full Text Available The modern power system is progressing from a synchronous machine-based system towards an inverter-dominated system, with large-scale penetration of renewable energy sources (RESs like wind and photovoltaics. RES units today represent a major share of the generation, and the traditional approach of integrating them as grid following units can lead to frequency instability. Many researchers have pointed towards using inverters with virtual inertia control algorithms so that they appear as synchronous generators to the grid, maintaining and enhancing system stability. This paper presents a literature review of the current state-of-the-art of virtual inertia implementation techniques, and explores potential research directions and challenges. The major virtual inertia topologies are compared and classified. Through literature review and simulations of some selected topologies it has been shown that similar inertial response can be achieved by relating the parameters of these topologies through time constants and inertia constants, although the exact frequency dynamics may vary slightly. The suitability of a topology depends on system control architecture and desired level of detail in replication of the dynamics of synchronous generators. A discussion on the challenges and research directions points out several research needs, especially for systems level integration of virtual inertia systems.

  8. Direct measurements of neutrino masses

    Holzschuh, E [Zurich Univ. (Switzerland). Inst. fuer Physik

    1996-11-01

    The direct measurements have so far given no indication for a nonzero (positive) mass of any of the three known neutrinos. The experiments measuring the tau and the muon neutrino are good shape. The tritium experiments are in an unfortunate situation. It is unclear to me whether the problems are experimental or theoretical or a combination of both. The electronic final states distribution have been calculated, but the results have never been tested experimentally. The most important question to be answered is about the validity of the sudden approximation. (author) 9 figs., 2 tabs., 16 refs.

  9. Enhanced motor learning with bilateral transcranial direct current stimulation: Impact of polarity or current flow direction?

    Naros, Georgios; Geyer, Marc; Koch, Susanne; Mayr, Lena; Ellinger, Tabea; Grimm, Florian; Gharabaghi, Alireza

    2016-04-01

    Bilateral transcranial direct current stimulation (TDCS) is superior to unilateral TDCS when targeting motor learning. This effect could be related to either the current flow direction or additive polarity-specific effects on each hemisphere. This sham-controlled randomized study included fifty right-handed healthy subjects in a parallel-group design who performed an exoskeleton-based motor task of the proximal left arm on three consecutive days. Prior to training, we applied either sham, right anodal (a-TDCS), left cathodal (c-TDCS), concurrent a-TDCS and c-TDCS with two independent current sources and return electrodes (double source (ds)-TDCS) or classical bilateral stimulation (bi-TDCS). Motor performance improved over time for both unilateral (a-TDCS, c-TDCS) and bilateral (bi-TDCS, ds-TDCS) TDCS montages. However, only the two bilateral paradigms led to an improvement of the final motor performance at the end of the training period as compared to the sham condition. There was no difference between the two bilateral stimulation conditions (bi-TDCS, ds-TDCS). Bilateral TDCS is more effective than unilateral stimulation due to its polarity-specific effects on each hemisphere rather than due to its current flow direction. This study is the first systematic evaluation of stimulation polarity and current flow direction of bi-hemispheric motor cortex TDCS on motor learning of proximal upper limb muscles. Copyright © 2016 International Federation of Clinical Neurophysiology. Published by Elsevier Ireland Ltd. All rights reserved.

  10. Directly measured currents and estimated transport pathways of Atlantic Water between 59.5°N and the Iceland–Faroes–Scotland Ridge

    Katelin H. Childers

    2015-11-01

    Full Text Available Using vessel-mounted acoustic Doppler current profiler data from four different routes between Scotland, Iceland and Greenland, we map out the mean flow of water in the top 400 m of the northeastern North Atlantic. The poleward transport east of the Reykjanes Ridge (RR decreases from ~8.5 to 10 Sv (1 Sverdrup=106 m3 s−1 at 59.5°N to 61°N to 6 Sv crossing the Iceland–Faroes–Scotland Ridge. The two longest ~1200 km transport integrals have 1.4–0.94 Sv uncertainty, respectively. The overall decrease in transport can in large measure be accounted for by a ~1.5 Sv flow across the RR into the Irminger Sea north of 59.5°N and by a ~0.5 Sv overflow of dense water along the Iceland–Faroes Ridge. A remaining 0.5 Sv flux divergence is at the edge of detectability, but if real could be accounted for through wintertime convection to >400 m and densification of upper ocean water. The topography of the Iceland Basin and the banks west of Scotland play a fundamental role in controlling flow pathways towards and past Iceland, the Faroes and Scotland. Most water flows north unimpeded through the Iceland Basin, some in the centre of the basin along the Maury Channel, and some along Hatton Bank, turning east along the northern slopes of George Bligh Bank, Lousy Bank and Bill Bailey's Bank, whereupon the flow splits with ~3 Sv turning northwest towards the Iceland–Faroes Ridge and the remainder continuing east towards and north of the Wyville-Thomson Ridge (WTR to the Scotland slope thereby increasing the Slope Current transport from ~1.5 Sv south of the WTR to 3.5 Sv in the Faroes–Shetland Channel.

  11. Transcranial direct current stimulation in psychiatric disorders

    Tortella, Gabriel; Casati, Roberta; Aparicio, Luana V M; Mantovani, Antonio; Senço, Natasha; D’Urso, Giordano; Brunelin, Jerome; Guarienti, Fabiana; Selingardi, Priscila Mara Lorencini; Muszkat, Débora; Junior, Bernardo de Sampaio Pereira; Valiengo, Leandro; Moffa, Adriano H; Simis, Marcel; Borrione, Lucas; Brunoni, André R

    2015-01-01

    The interest in non-invasive brain stimulation techniques is increasing in recent years. Among these techniques, transcranial direct current stimulation (tDCS) has been the subject of great interest among researchers because of its easiness to use, low cost, benign profile of side effects and encouraging results of research in the field. This interest has generated several studies and randomized clinical trials, particularly in psychiatry. In this review, we provide a summary of the development of the technique and its mechanism of action as well as a review of the methodological aspects of randomized clinical trials in psychiatry, including studies in affective disorders, schizophrenia, obsessive compulsive disorder, child psychiatry and substance use disorder. Finally, we provide an overview of tDCS use in cognitive enhancement as well as a discussion regarding its clinical use and regulatory and ethical issues. Although many promising results regarding tDCS efficacy were described, the total number of studies is still low, highlighting the need of further studies aiming to replicate these findings in larger samples as to provide a definite picture regarding tDCS efficacy in psychiatry. PMID:25815258

  12. Current-ripple effect on superconductive dc critical current measurements

    Goodrich, L.F.; Bray, S.L.; Clark, A.F.

    1988-01-01

    The effect of sample-current power-supply ripple on dc critical current measurement in multifilamentary NbTi superconductors was evaluated. In general the ripple in a current supply became more significant above 500 A because effective filtering was hard to achieve. Ripple also caused noise at the input of the voltmeter used for the measurements. The quantitative effect of current ripple was studied using a battery current supply modified to allow the creation of ripple current with variable frequency and amplitude. Problems common to all large-conductor critical current measurements are discussed

  13. Transcranial Direct Current Stimulation in Neurodegenerative Disease

    Argye E. Hillis

    2014-04-01

    Full Text Available We review rationale, challenges, study designs, reported results, and future directions in the use of transcranial direct cranial stimulation (tDCS in neurodegenerative disease, focusing on treatment of spelling in primary progressive aphasia (PPA. Rationale Evidence from both animal studies and human studies indicates that anodal and cathodal tDCS over the brain result in a temporary change in membrane potentials, reducing the threshold for long-term potentiation of neurons in the affected area. This may allow unaffected brain regions to assume functions of diseased regions. Challenges Special challenges in treating individuals with progressive conditions include altered goals of treatment and the possibility that participants may accumulate new deficits over the course of the treatment program that interfere with their ability to understand, retain, or cooperate with aspects of the program. The most serious challenge – particularly for single case designs - is that there may be no stable baseline against which to measure change with treatment. Thus, it is essential to demonstrate that treatment results in a statistically significant change in the slope of decline or improvement. Therefore, demonstration of a significant difference between tDCS and control (sham requires either a large number of participants or a large effect size. Designs The choice of a treatment design reflects these limitations. Group studies with a randomized, double-blind, sham control trial design (without cross-over provide the greatest power to detect a difference between intervention and control conditions, with the fewest participants. A cross-over design, in which all participants (from 1 to many receive both active and sham conditions, in randomized order, requires a larger effect size for the active condition relative to the control condition (or little to no maintenance of treatment gains or carry-over effect to show significant differences between treatment

  14. Cellular Mechanisms of Transcranial Direct Current Stimulation

    2016-07-14

    fEPSP responses are significantly (P < 0.05, *) facilitated with +8 V/m fields ( left ) and reduced with -8 V/m ( right ) in three pathways. In each...cortex results in a sustained modulation of synaptic efficacy. A) Schematic of anodal ( left ) and cathodal ( right ) DCS with current flow along the...current stimulation (tDCS) delivered 1day vs . 1week after cerebral ischemia in rats. Brain Res. Zimerman M, Nitsch M, Giraux P, Gerloff C, Cohen LG

  15. Multibloc system electronic equipment: D.C. linear - logarithmic amplifier and periodmeter and wide range (pulses, fluctuations and direct current) measuring set

    Guerre, J.; Plaige, Y.; Vaux, C.

    1974-01-01

    The requirements which have led to the design of a specific equipment for reactor neutron control (Multibloc system) are briefly recalled. It is shown how, for reasons of saving the cost of installation, the development tended towards a multifunction performance from signals delivered by one detector. Two major achievments in accordance with the above trend are described: the D.C. linear - logarithmic amplifier and periodmeter, and the wide dynamics range measuring set [fr

  16. Loyalty Programmes : Current Knowledge and Research Directions

    Dorotic, Matilda; Bijmolt, Tammo H. A.; Verhoef, Peter C.

    Loyalty programmes (LPs) have increased in number and popularity, but their effects on customer behaviour remain equivocal, due to a lack of understanding of the drivers of LP effectiveness and insufficient generalizable conclusions across prior studies. This paper synthesizes current knowledge

  17. College Advising: Current Perceptions, Future Directions.

    Chapman, David W.; Gill, Stephen J.

    1981-01-01

    Examines the college admissions activities that high school counselors believe are most effective in providing accurate information to students. Also examines the current role of the counselor in college advising and reports on what counselors predict will be the trends in college advising. (Author/RC)

  18. Hybrid Direct-Current Circuit Breaker

    Wang, Ruxi (Inventor); Premerlani, William James (Inventor); Caiafa, Antonio (Inventor); Pan, Yan (Inventor)

    2017-01-01

    A circuit breaking system includes a first branch including at least one solid-state snubber; a second branch coupled in parallel to the first branch and including a superconductor and a cryogenic contactor coupled in series; and a controller operatively coupled to the at least one solid-state snubber and the cryogenic contactor and programmed to, when a fault occurs in the load circuit, activate the at least one solid-state snubber for migrating flow of the electrical current from the second branch to the first branch, and, when the fault is cleared in the load circuit, activate the cryogenic contactor for migrating the flow of the electrical current from the first branch to the second branch.

  19. Tissue Engineering: Current Strategies and Future Directions

    Olson, Jennifer L.; Atala, Anthony; Yoo, James J.

    2011-01-01

    Novel therapies resulting from regenerative medicine and tissue engineering technology may offer new hope for patients with injuries, end-stage organ failure, or other clinical issues. Currently, patients with diseased and injured organs are often treated with transplanted organs. However, there is a shortage of donor organs that is worsening yearly as the population ages and as the number of new cases of organ failure increases. Scientists in the field of regenerative medicine and tissue eng...

  20. Medical Robots: Current Systems and Research Directions

    Ryan A. Beasley

    2012-01-01

    Full Text Available First used medically in 1985, robots now make an impact in laparoscopy, neurosurgery, orthopedic surgery, emergency response, and various other medical disciplines. This paper provides a review of medical robot history and surveys the capabilities of current medical robot systems, primarily focusing on commercially available systems while covering a few prominent research projects. By examining robotic systems across time and disciplines, trends are discernible that imply future capabilities of medical robots, for example, increased usage of intraoperative images, improved robot arm design, and haptic feedback to guide the surgeon.

  1. Current adaptation measures and policies

    Geoff Roberts; John A. Parrotta; Anita. Wreford

    2009-01-01

    As stated in earlier chapters, the possible impacts of climate change on forests and the forest sector are considerable, and many impacts have already been observed. As forest conditions change, there is an inherent need to change management and policy measures to minimise negative impacts and to exploit the benefits derived from climate change. This chapter highlights...

  2. Leadership: current theories, research, and future directions.

    Avolio, Bruce J; Walumbwa, Fred O; Weber, Todd J

    2009-01-01

    This review examines recent theoretical and empirical developments in the leadership literature, beginning with topics that are currently receiving attention in terms of research, theory, and practice. We begin by examining authentic leadership and its development, followed by work that takes a cognitive science approach. We then examine new-genre leadership theories, complexity leadership, and leadership that is shared, collective, or distributed. We examine the role of relationships through our review of leader member exchange and the emerging work on followership. Finally, we examine work that has been done on substitutes for leadership, servant leadership, spirituality and leadership, cross-cultural leadership, and e-leadership. This structure has the benefit of creating a future focus as well as providing an interesting way to examine the development of the field. Each section ends with an identification of issues to be addressed in the future, in addition to the overall integration of the literature we provide at the end of the article.

  3. Behavioral cardiology: current advances and future directions.

    Rozanski, Alan

    2014-07-08

    Growing epidemiological evidence identifies key domains relevant to behavioral cardiology, including health behaviors, emotions, mental mindsets, stress management, social connectedness, and a sense of purpose. Each of these domains exists along a continuum, ranging from positive factors that promote health, to negative factors, which are pathophysiological. To date, there has been relatively little translation of this growing knowledge base into cardiology practice. Four initiatives are proposed to meet this challenge: 1) promulgating greater awareness of the potency of psychosocial risks factors; 2) overcoming a current "artificial divide" between conventional and psychosocial risk factors; 3) developing novel cost-effective interventions using Internet and mobile health applications, group-based counseling, and development of tiered-care behavioral management; and 4) in recognition that "one size does not fit all" with respect to behavioral interventions, developing specialists who can counsel patients in multidisciplinary fashion and use evidence-based approaches for promoting patient motivation and execution of health goals. Copyright © 2014 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.

  4. Teledermatology. Current status and future directions.

    Whited, J D

    2001-01-01

    Teledermatology is becoming an increasingly common means of delivering dermatologic healthcare worldwide and will almost certainly play a greater role in the future. The type of technology used distinguishes the 2 modes of teledermatology consultation. The store and forward technique uses still digital images generated by a digital camera. Consultations of this type are considered asynchronous since the images are obtained, sent, and reviewed at different times. In contrast, real-time interactive consultations are synchronous. Patients and clinicians interact in real-time through an audio-video communication link. Each modality has its advantages and disadvantages, and studies appear in the literature that assess both technologies. Although diagnostic reliability (precision) assessments for teledermatology are subject to limitations, existing information indicates that both store and forward and real-time interactive technology result in reliable diagnostic outcomes when compared with clinic-based evaluations. Less information regarding diagnostic accuracy is available; however, one evaluation that used store and forward technology found comparable diagnostic accuracy between teledermatology consultations and clinic-based examinations. Currently, little information is available regarding cost effectiveness and patient outcomes. Existing evidence, while inconclusive, suggests that teledermatology may be more costly than traditional clinic-based care, especially when using real-time interactive technology. Teledermatology has been shown to have utility as a triage mechanism for determining the urgency or need for a clinic-based consultation. Overall, patients appear to accept teledermatology and are satisfied with it as a means of obtaining healthcare. Clinicians have also generally reported positive experiences with teledermatology. Future studies that focus on cost effectiveness, patient outcomes, and patient and clinician satisfaction will help further define the

  5. Telehealth: current practices and future directions

    David, Yadin B.

    1996-02-01

    When we review the positive impact that the integration of ostensibly independent patient-care services have on the efficient management of quality care, education, and collaborative research, it is not surprising that telehealth deployment is on the rise. The forces that drive this phenomenon include: the need to manage the entire disease episode; the desire for wider geographically-distributed quality health care; the escalation of customer expectations; globalization of healthcare and its support services; an increase in patient and provider convenience; and the acceptance of the present technological community. At the Telehealth Center at the Texas Children's Hospital, current classifications of clinical applications are listed: (1) initial urgent evaluation of patients, (2) triage decisions and pretransfer arrangements, (3) medical and surgical follow-up and medication review, (4) consultation for primary care encounters, (5) real-time subspecialty care consultation and planning, (6) management of chronic diseases and conditions, (7) extended diagnostic work-ups, (8) review of diagnostic images, and (9) preventive medicine and patient education. The delivery of such services is associated with challenges and opportunities. As we move forward from limited data processing to an integrated communication system, from centralized main frame functions to personalized and location-independent workstations, and from hospitals to clinics and homecare, an increase in the minimum features provided by the equipment and the communication systems must accompany the widening variety of clinical applications. Future expansion of telehealth systems stands to revolutionize the delivery of services to the benefits of providers' networks, our economy, and patients through integration.

  6. Measurement technology of RF interference current in high current system

    Zhao, Zhihua; Li, Jianxuan; Zhang, Xiangming; Zhang, Lei

    2018-06-01

    Current probe is a detection method commonly used in electromagnetic compatibility. With the development of power electronics technology, the power level of power conversion devices is constantly increasing, and the power current of the electric energy conversion device in the electromagnetic launch system can reach 10kA. Current probe conventionally used in EMC (electromagnetic compatibility) detection cannot meet the test requirements on high current system due to the magnetic saturation problem. The conventional high current sensor is also not suitable for the RF (Radio Frequency) interference current measurement in high current power device due to the high noise level in the output of active amplifier. In this paper, a passive flexible current probe based on Rogowski coil and matching resistance is proposed that can withstand high current and has low noise level, to solve the measurement problems of interference current in high current power converter. And both differential mode and common mode current detection can be easily carried out with the proposed probe because of the probe's flexible structure.

  7. High current density ion beam measurement techniques

    Ko, W.C.; Sawatzky, E.

    1976-01-01

    High ion beam current measurements are difficult due to the presence of the secondary particles and beam neutralization. For long Faraday cages, true current can be obtained only by negative bias on the target and by summing the cage wall and target currents; otherwise, the beam will be greatly distorted. For short Faraday cages, a combination of small magnetic field and the negative target bias results in correct beam current. Either component alone does not give true current

  8. Direct measurements of neutrino mass

    Robertson, R.G.H.

    1991-01-01

    Some recent developments in the experimental search for neutrino mass are discussed. New data from Los Alamos on the electron neutrino mass as measured in tritium beta decay give an upper limit of 9.3 eV at the 95% confidence level. This result is not consistent with the long-standing ITEP result of 26(5) eV within a ''model-independent'' range of 17 to 40 eV. It now appears that the electron neutrino is not sufficiently massive to close the universe by itself. Hime and Jelley report finding new evidence for a 17-keV neutrino in the Β decay of 35 S and 63 Ni. Many other experiments are being reported and the situation is still unresolved. 56 refs., 1 fig., 3 tabs

  9. Sensorless optimal sinusoidal brushless direct current for hard disk drives

    Soh, C. S.; Bi, C.

    2009-04-01

    Initiated by the availability of digital signal processors and emergence of new applications, market demands for permanent magnet synchronous motors have been surging. As its back-emf is sinusoidal, the drive current should also be sinusoidal for reducing the torque ripple. However, in applications like hard disk drives, brushless direct current (BLDC) drive is adopted instead of sinusoidal drive for simplification. The adoption, however, comes at the expense of increased harmonics, losses, torque pulsations, and acoustics. In this paper, we propose a sensorless optimal sinusoidal BLDC drive. First and foremost, the derivation for an optimal sinusoidal drive is presented, and a power angle control scheme is proposed to achieve an optimal sinusoidal BLDC. The scheme maintains linear relationship between the motor speed and drive voltage. In an attempt to execute the sensorless drive, an innovative power angle measurement scheme is devised, which takes advantage of the freewheeling diodes and measures the power angle through the detection of diode voltage drops. The objectives as laid out will be presented and discussed in this paper, supported by derivations, simulations, and experimental results. The proposed scheme is straightforward, brings about the benefits of sensorless sinusoidal drive, negates the need for current sensors by utilizing the freewheeling diodes, and does not incur additional cost.

  10. Measuring Electrical Current: The Roads Not Taken

    Greenslade, Thomas B., Jr.

    2011-01-01

    Recently I wrote about the standard Weston meter movement, that is at the heart of all modern analogue current measurements. Now I will discuss other techniques used to measure electric current that, despite being based on valid physical principles, are largely lost in technological history.

  11. Methodology and technology for peripheral and central blood pressure and blood pressure variability measurement: current status and future directions - Position statement of the European Society of Hypertension Working Group on blood pressure monitoring and cardiovascular variability.

    Stergiou, George S; Parati, Gianfranco; Vlachopoulos, Charalambos; Achimastos, Apostolos; Andreadis, Emanouel; Asmar, Roland; Avolio, Alberto; Benetos, Athanase; Bilo, Grzegorz; Boubouchairopoulou, Nadia; Boutouyrie, Pierre; Castiglioni, Paolo; de la Sierra, Alejandro; Dolan, Eamon; Head, Geoffrey; Imai, Yutaka; Kario, Kazuomi; Kollias, Anastasios; Kotsis, Vasilis; Manios, Efstathios; McManus, Richard; Mengden, Thomas; Mihailidou, Anastasia; Myers, Martin; Niiranen, Teemu; Ochoa, Juan Eugenio; Ohkubo, Takayoshi; Omboni, Stefano; Padfield, Paul; Palatini, Paolo; Papaioannou, Theodore; Protogerou, Athanasios; Redon, Josep; Verdecchia, Paolo; Wang, Jiguang; Zanchetti, Alberto; Mancia, Giuseppe; O'Brien, Eoin

    2016-09-01

    Office blood pressure measurement has been the basis for hypertension evaluation for almost a century. However, the evaluation of blood pressure out of the office using ambulatory or self-home monitoring is now strongly recommended for the accurate diagnosis in many, if not all, cases with suspected hypertension. Moreover, there is evidence that the variability of blood pressure might offer prognostic information that is independent of the average blood pressure level. Recently, advancement in technology has provided noninvasive evaluation of central (aortic) blood pressure, which might have attributes that are additive to the conventional brachial blood pressure measurement. This position statement, developed by international experts, deals with key research and practical issues in regard to peripheral blood pressure measurement (office, home, and ambulatory), blood pressure variability, and central blood pressure measurement. The objective is to present current achievements, identify gaps in knowledge and issues concerning clinical application, and present relevant research questions and directions to investigators and manufacturers for future research and development (primary goal).

  12. Fast measure proceeding of weak currents

    Taieb, J.

    1953-01-01

    The process of fast measure of the weak currents that we are going to describe briefly apply worthy of the provided currents by the sources to elevated value internal resistance, as it is the case for the ionization chamber, the photocells, mass spectroscopic tubes. The problem to measure weak currents is essentially a problem of amplifier and of input circuit. We intended to achieve a whole amplifier and input circuit with advanced performances, meaning that for a measured celerity we wanted to have an signal/noise ratio the most important as in the classic systems and for a same report signal/noise a more quickly done measure. (M.B.) [fr

  13. Direct currents produced by hf heating of plasma

    Klima, R.

    1974-01-01

    In addition to the well-known diffusion currents, toroidal direct currents arise in h.f. heated plasmas as a result of a momentum transfer from the h.f. field to plasma particles. The estimates of steady-state conditions are given for these currents. Particularly, the possibility of stationary operation of a Tokamak device is analyzed. (author)

  14. Direct Drive Generator for Renewable Power Conversion from Water Currents

    Segergren, Erik

    2005-01-01

    In this thesis permanent magnet direct drive generator for power conversion from water currents is studied. Water currents as a power source involves a number of constrains as well as possibilities, especially when direct drive and permanent magnets are considered. The high power fluxes and low current velocities of a water current, in combination with its natural variations, will affect the way the generator is operated and, flowingly, the appearance of the generator. The work in this thesis can, thus, be categorized into two general topics, generator technology and optimization. Under the first topic, fundamental generator technology is used to increase the efficiency of a water current generator. Under the latter topic, water current generators are optimized to a specific environment. The conclusion drawn from this work is that it is possible to design very low speed direct drive generators with good electromagnetic properties and wide efficiency peak

  15. Local eddy current measurements in pulsed fields

    Espina-Hernandez, J.H. [SEPI-Electronica, ESIME-IPN, UPALM Edif. ' Z' . Zacatenco, Mexico DF 07738 (Mexico)], E-mail: jhespina@gmail.com; Groessinger, R. [Institute of Solid State Physics, Vienna University of Technology, Wiedner Hauptstrasse 8-10, A-1040 Vienna (Austria); Hallen, J.M. [Departamento de Ingenieria Metalurgica, IPN-ESIQIE, UPALM Edif. 7, Zacatenco, Mexico DF 07738 (Mexico)

    2008-07-15

    This work presents new eddy current measurements in pulsed fields. A commercial point pick-up coil is used to detect the induction signal along the radius of Cu and Al samples with cylindrical shape and diameters between 5 and 35 mm. Local eddy current measurements were performed on the surface of conducting materials due to the small dimensions of the coil. A simple electrical circuit, used as a model, is proposed to describe the local eddy current effect in pulsed fields. The proposed model allows to calculate the phase shift angle between the signal proportional to eddy currents and the applied external field in a pulsed field magnetometer.

  16. Zero current measurements using the Rogowski coil

    Gregor, J.; Jakubova, I.; Kadlec, P.; Senk, J.; Vavra, Z.

    1997-01-01

    The zero current measurements using the Rogowski coil carried out on the model of the extinguishing chamber of hv SF 6 circuit breaker with self-flow generation are presented in the paper. The time course of the post-arc current obtained by numerical integration of the measured induced voltage of the Rogowski coil gives information not only about the value of the residual current after the successful interruption but also about the current changes connected with the dynamic behaviour of the arc during its quenching. (author)

  17. Transcranial Direct Current Stimulation Improves Audioverbal Memory in Stroke Patients.

    Kazuta, Toshinari; Takeda, Kotaro; Osu, Rieko; Tanaka, Satoshi; Oishi, Ayako; Kondo, Kunitsugu; Liu, Meigen

    2017-08-01

    The aim of this study was to investigate whether anodal transcranial direct current stimulation over the left temporoparietal area improved audioverbal memory performance in stroke patients. Twelve stroke patients with audioverbal memory impairment participated in a single-masked, crossover, and sham-controlled experiment. The anodal or sham transcranial direct current stimulation was applied during the Rey Auditory Verbal Learning Test, which evaluates the ability to recall a list of 15 heard words over five trials. The number of correctly recalled words was compared between the anodal and sham conditions and the influence of transcranial direct current stimulation on serial position effect of the 15 words was also examined. The increase in the number of correctly recalled words from the first to the fifth trial was significantly greater in the anodal condition than in the sham condition (P transcranial direct current stimulation over the left temporoparietal area improved audioverbal memory performance and induced the primacy effect in stroke patients.

  18. Continuous measurement of an atomic current

    Laflamme, C.; Yang, D.; Zoller, P.

    2017-04-01

    We are interested in dynamics of quantum many-body systems under continuous observation, and its physical realizations involving cold atoms in lattices. In the present work we focus on continuous measurement of atomic currents in lattice models, including the Hubbard model. We describe a Cavity QED setup, where measurement of a homodyne current provides a faithful representation of the atomic current as a function of time. We employ the quantum optical description in terms of a diffusive stochastic Schrödinger equation to follow the time evolution of the atomic system conditional to observing a given homodyne current trajectory, thus accounting for the competition between the Hamiltonian evolution and measurement back action. As an illustration, we discuss minimal models of atomic dynamics and continuous current measurement on rings with synthetic gauge fields, involving both real space and synthetic dimension lattices (represented by internal atomic states). Finally, by "not reading" the current measurements the time evolution of the atomic system is governed by a master equation, where—depending on the microscopic details of our CQED setups—we effectively engineer a current coupling of our system to a quantum reservoir. This provides interesting scenarios of dissipative dynamics generating "dark" pure quantum many-body states.

  19. Zener diode controls switching of large direct currents

    1965-01-01

    High-current zener diode is connected in series with the positive input terminal of a dc supply to block the flow of direct current until a high-frequency control signal is applied across the zener diode. This circuit controls the switching of large dc signals.

  20. Helicopter Rotor Noise Prediction: Background, Current Status, and Future Direction

    Brentner, Kenneth S.

    1997-01-01

    Helicopter noise prediction is increasingly important. The purpose of this viewgraph presentation is to: 1) Put into perspective the recent progress; 2) Outline current prediction capabilities; 3) Forecast direction of future prediction research; 4) Identify rotorcraft noise prediction needs. The presentation includes an historical perspective, a description of governing equations, and the current status of source noise prediction.

  1. Soft commutated direct current motor [summary of proposed paper

    Hsu, John S.

    1998-10-22

    A novel soft commutated direct current (DC) motor is introduced. The current of the commutated coil is intentionally drained before the brush disconnects the coil. This prevents the spark generation that normally occurs in conventional DC motors. A similar principle can be applied for DC generators.

  2. Effect of alternating and direct currents on Pseudomonas ...

    The test media were Muller-Hinton agar and eosin methylene blue (EMB) agar. In this research Pseudomonas aeruginosa which was isolated from patients wounds was examined with levels of alternating and direct current (AC and DC) electrical stimulation (1.5V, 3.5V, 5.5V and 10V) to see if these currents could inhibit P.

  3. Sensitive beam current measurement for FAIR

    Schwickert, Marcus; Kurian, Febin; Reeg, Hansjoerg [GSI Helmholtzzentrum fuer Schwerionenforschung GmbH, Darmstadt (Germany); Seidel, Paul; Neubert, Ralf [Friedrich-Schiller-Universitaet Jena (Germany); Geithner, Rene; Vodel, Wolfgang [Helmholtz-Institut Jena (Germany)

    2012-07-01

    Presently FAIR, the Facility for Antiproton and Ion Research, entered the final planning phase at GSI. The new accelerator facility requires precise devices for beam current measurements due to the large dynamics in beam intensities for the various synchrotrons, transport lines and storage rings. We report on the actual developments of beam diagnostic devices for the measurement of beam intensities ranging from 5 x 10{sup 11} uranium ions down to the detection of less than 10{sup 4} antiprotons. This contribution gives an overview of the planned instruments with a focus on non-intercepting beam current transformers, and summarizes the on-going development of a cryogenic current comparator.

  4. Automatic system for ionization chamber current measurements

    Brancaccio, Franco; Dias, Mauro S.; Koskinas, Marina F.

    2004-01-01

    The present work describes an automatic system developed for current integration measurements at the Laboratorio de Metrologia Nuclear of Instituto de Pesquisas Energeticas e Nucleares. This system includes software (graphic user interface and control) and a module connected to a microcomputer, by means of a commercial data acquisition card. Measurements were performed in order to check the performance and for validating the proposed design

  5. Effect-directed analysis: Current status and future challenges

    Hong, Seongjin; Giesy, John P.; Lee, Jung-Suk; Lee, Jong-Hyeon; Khim, Jong Seong

    2016-09-01

    Effect-directed analysis (EDA) has become useful for identification of toxicant(s) that occur in mixtures in the environment, especially those that are causative agents of specific adverse effects. Here, we summarize and review EDA methodology including preparation of samples, biological analyses, fractionations, and instrumental analyses, highlighting key scientific advancements. A total of 63 documents since 1999 (Scopus search) including 46 research articles, 13 review papers, and 4 project descriptions, have been collected and reviewed in this study. At the early stage (1999-2010), most studies that applied EDA focused on organic extracts of freshwater and coastal contaminated sediments and wastewater. Toxic effects were often measured using cell-based bioassays ( in vitro) and the causative chemicals were identified by use of low resolution gas chromatography with mass selective detector (GCMSD). More recently (2010-present), EDA has been extended to various matrices such as biota, soil, crude oil, and suspended solids and techniques have been improved to include determination of bioavailability in vivo. In particular, methods for non-target screenings of organic chemicals in environmental samples using cutting-edge instrumentation such as time of flight-mass spectrometry (ToF-MS), Fourier transform-ion cyclotron resonance (FT-ICR), and Orbitrap mass spectrometer have been developed. This overview provides descriptions of recent improvements of EDA and suggests future research directions based on current understandings and limitations.

  6. Online junction temperature measurement using peak gate current

    Baker, Nick; Munk-Nielsen, Stig; Iannuzzo, Francesco

    2015-01-01

    A new method for junction temperature measurement of MOS-gated power semiconductor switches is presented. The measurement method involves detecting the peak voltage over the external gate resistor of an IGBT or MOSFET during turn-on. This voltage is directly proportional to the peak gate current...

  7. Cerebellar transcranial direct current stimulation modulates verbal working memory.

    Boehringer, Andreas; Macher, Katja; Dukart, Juergen; Villringer, Arno; Pleger, Burkhard

    2013-07-01

    Neuroimaging studies show cerebellar activations in a wide range of cognitive tasks and patients with cerebellar lesions often present cognitive deficits suggesting a cerebellar role in higher-order cognition. We used cathodal transcranial direct current stimulation (tDCS), known to inhibit neuronal excitability, over the cerebellum to investigate if cathodal tDCS impairs verbal working memory, an important higher-order cognitive faculty. We tested verbal working memory as measured by forward and backward digit spans in 40 healthy young participants before and after applying cathodal tDCS (2 mA, stimulation duration 25 min) to the right cerebellum using a randomized, sham-controlled, double-blind, cross-over design. In addition, we tested the effect of cerebellar tDCS on word reading, finger tapping and a visually cued sensorimotor task. In line with lower digit spans in patients with cerebellar lesions, cerebellar tDCS reduced forward digit spans and blocked the practice dependent increase in backward digit spans. No effects of tDCS on word reading, finger tapping or the visually cued sensorimotor task were found. Our results support the view that the cerebellum contributes to verbal working memory as measured by forward and backward digit spans. Moreover, the induction of reversible "virtual cerebellar lesions" in healthy individuals by means of tDCS may improve our understanding of the mechanistic basis of verbal working memory deficits in patients with cerebellar lesions. Copyright © 2013 Elsevier Inc. All rights reserved.

  8. Cryogenic current comparators for precise ion beam current measurements

    Kurian, Febin

    2015-01-01

    The planned Facility for Antiproton and Ion Research (FAIR) at GSI has to cope with a wide range of beam intensities in its high-energy beam transport systems and in the storage rings. To meet the requirements of a non-intercepting intensity measurement down to nA range, it is planned to install a number of Cryogenic Current Comparator (CCC) units at different locations in the FAIR beamlines. In this work, the first CCC system for intensity measurement of heavy ion beams, which was developed at GSI, was re-commissioned and upgraded to be used as a 'GSI - CCC prototype' for extensive optimization and development of an improved CCC for FAIR. After installation of a new SQUID sensor and related electronics, as well as implementation of improved data acquisition components, successful beam current measurements were performed at a SIS18 extraction line. The measured intensity values were compared with those of a Secondary Electron Monitor (SEM). Furthermore, the spill-structure of a slowly extracted beam was measured and analyzed, investigating its improvement due to bunching during the slow-extraction process. Due to the extreme sensitivity of the superconducting sensor, the determined intensity values as well as the adjustment of the system for optimal performance are strongly influenced by the numerous noise sources of the accelerators environment. For this reason, detailed studies of different effects caused by noise have been carried out, which are presented together with proposals to reduce them. Similarly, studies were performed to increase the dynamic range and overcome slew rate limitations, the results of which are illustrated and discussed as well. By combining the various optimizations and characterizations of the GSI CCC prototype with the experiences made during beam operation, criteria for a more efficient CCC System could be worked out, which are presented in this work. The details of this new design are worked out with respect to the

  9. Current Directional Protection of Series Compensated Line Using Intelligent Classifier

    M. Mollanezhad Heydarabadi

    2016-12-01

    Full Text Available Current inversion condition leads to incorrect operation of current based directional relay in power system with series compensated device. Application of the intelligent system for fault direction classification has been suggested in this paper. A new current directional protection scheme based on intelligent classifier is proposed for the series compensated line. The proposed classifier uses only half cycle of pre-fault and post fault current samples at relay location to feed the classifier. A lot of forward and backward fault simulations under different system conditions upon a transmission line with a fixed series capacitor are carried out using PSCAD/EMTDC software. The applicability of decision tree (DT, probabilistic neural network (PNN and support vector machine (SVM are investigated using simulated data under different system conditions. The performance comparison of the classifiers indicates that the SVM is a best suitable classifier for fault direction discriminating. The backward faults can be accurately distinguished from forward faults even under current inversion without require to detect of the current inversion condition.

  10. Eddy currents in pulsed field measurements

    Kuepferling, M.; Groessinger, R.; Wimmer, A.; Taraba, M.; Scholz, W.

    2002-01-01

    Full text: One problem of pulsed field magnetometry is an error in magnetization, which appears in measurements of conducting samples. This error is due to eddy currents induced by a time varying field. To allow predictions how eddy currents exert influence on the hysteresis loop, systematic experimental and theoretical studies of pulsed field measurements of metallic samples were performed. The theoretical studies include analytical calculations as well as numerical ones using a 2D finite element software. In the measurements three physical parameters have been varied: i) the conductivity of the sample by using two different materials, in this case technical Cu and Al ii) size and shape of the sample by using cylinders, spheres and cuboids iii) the pulse duration of the external field by changing the capacitor battery from 8mF ( =9.1ms) to 24mF ( =15.7ms). The time dependence of the external field corresponds with a pulsed damped harmonic oscillation with a maximum value of 5.2T. The samples were studied in the as cast state (after machining) as well as after heat treatment. Theoretical calculations showed not only good agreement with the absolute values of the measured eddy current m agnetization , they also gave an explanation of the shape of the eddy current hysteresis and the dependence of the eddy current 'magnetization' on parameters as pulse duration of the external field and conductivity of the sample. (author)

  11. Leakage current measurement in transformerless PV inverters

    Kerekes, Tamas; Sera, Dezso; Mathe, Laszlo

    2012-01-01

    Photovoltaic (PV) installations have seen a huge increase during the last couple of years. Transformerless PV inverters are gaining more share of the total inverter market, due to their high conversion efficiency, small weight and size. Nevertheless safety should have an important role in case...... of these tranformerless systems, due to the missing galvanic isolation. Leakage and fault current measurement is a key issue for these inverter topologies to be able to comply with the required safety standards. This article presents the test results of two different current measurement sensors that were suggested...

  12. Electronegative Gas Thruster - Direct Thrust Measurement Project

    Dankanich, John (Principal Investigator); Aanesland, Ane; Polzin, Kurt; Walker, Mitchell

    2015-01-01

    This effort is an international collaboration and academic partnership to mature an innovative electric propulsion (EP) thruster concept to TRL 3 through direct thrust measurement. The initial target application is for Small Satellites, but can be extended to higher power. The Plasma propulsion with Electronegative GASES (PEGASES) concept simplifies ion thruster operation, eliminates a neutralizer requirement and should yield longer life capabilities and lower cost implementation over conventional gridded ion engines. The basic proof-of concept has been demonstrated and matured to TRL 2 over the past several years by researchers at the Laboratoire de Physique des Plasma in France. Due to the low maturity of the innovation, there are currently no domestic investments in electronegative gas thrusters anywhere within NASA, industry or academia. The end product of this Center Innovation Fund (CIF) project will be a validation of the proof-of-concept, maturation to TRL 3 and technology assessment report to summarize the potential for the PEGASES concept to supplant the incumbent technology. Information exchange with the foreign national will be one-way with the exception of the test results. Those test results will first go through a standard public release ITAR/export control review, and the results will be presented in a public technical forum, and the results will be presented in a public technical forum.

  13. Current status and future direction of the MONK software package

    Smith, Nigel; Armishaw, Malcolm; Cooper, Andrew

    2003-01-01

    The current status of the MONK criticality software package is summarized in terms of recent and current developments and envisaged directions for the future. The areas of the discussion are physics modeling, geometry modeling, source modeling, nuclear data, validation, supporting tools and customer services. In future development plan, MONK continues to be focused on meeting the short and long-term needs of the code user community. (J.P.N.)

  14. Technology-based suicide prevention: current applications and future directions.

    Luxton, David D; June, Jennifer D; Kinn, Julie T

    2011-01-01

    This review reports on current and emerging technologies for suicide prevention. Technology-based programs discussed include interactive educational and social networking Web sites, e-mail outreach, and programs that use mobile devices and texting. We describe innovative applications such as virtual worlds, gaming, and text analysis that are currently being developed and applied to suicide prevention and outreach programs. We also discuss the benefits and limitations of technology-based applications and discuss future directions for their use.

  15. Multichannel measuring instrument of small currents

    Kunetsov, A.N.; Kuznetsov, E.A.

    2009-01-01

    The device intended for display of a profile of an ion beam by measurement of currents of the co-ordinate wires is developed. Technical characteristics, basic electric and logic schemes, time diagrams, and also photos of the basic parts of the device are presented

  16. Differential modulation of corticospinal excitability by different current densities of anodal transcranial direct current stimulation.

    Andisheh Bastani

    Full Text Available BACKGROUND: Novel non-invasive brain stimulation techniques such as transcranial direct current stimulation (tDCS have been developed in recent years. TDCS-induced corticospinal excitability changes depend on two important factors current intensity and stimulation duration. Despite clinical success with existing tDCS parameters, optimal protocols are still not entirely set. OBJECTIVE/HYPOTHESIS: The current study aimed to investigate the effects of four different anodal tDCS (a-tDCS current densities on corticospinal excitability. METHODS: Four current intensities of 0.3, 0.7, 1.4 and 2 mA resulting in current densities (CDs of 0.013, 0.029, 0.058 and 0.083 mA/cm(2 were applied on twelve right-handed (mean age 34.5±10.32 yrs healthy individuals in different sessions at least 48 hours apart. a-tDCS was applied continuously for 10 minute, with constant active and reference electrode sizes of 24 and 35 cm(2 respectively. The corticospinal excitability of the extensor carpi radialis muscle (ECR was measured before and immediately after the intervention and at 10, 20 and 30 minutes thereafter. RESULTS: Post hoc comparisons showed significant differences in corticospinal excitability changes for CDs of 0.013 mA/cm(2 and 0.029 mA/cm(2 (P = 0.003. There were no significant differences between excitability changes for the 0.013 mA/cm(2 and 0.058 mA/cm(2 (P = 0.080 or 0.013 mA/cm(2 and 0.083 mA/cm(2 (P = 0.484 conditions. CONCLUSION: This study found that a-tDCS with a current density of 0.013 mA/cm(2 induces significantly larger corticospinal excitability changes than CDs of 0.029 mA/cm(2. The implication is that might help to avoid applying unwanted amount of current to the cortical areas.

  17. Direct calculation of current drive efficiency in FISIC code

    Wright, J.C.; Phillips, C.K.; Bonoli, P.T.

    1996-01-01

    Two-dimensional RF modeling codes use a parameterization (1) of current drive efficiencies to calculate fast wave driven currents. This parameterization assumes a uniform quasi-linear diffusion coefficient and requires a priori knowledge of the wave polarizations. These difficulties may be avoided by a direct calculation of the quasilinear diffusion coefficient from the Kennel-Englemann form with the field polarizations calculated by the full wave code, FISIC (2). Current profiles are calculated using the adjoint formulation (3). Comparisons between the two formulations are presented. copyright 1996 American Institute of Physics

  18. Transcranial direct current stimulation enhances propulsion during walking

    van Asseldonk, Edwin H.F.; Jensen, W.; Andersen, O.K.; Akay, M

    2014-01-01

    Transcranial direct current stimulation (tDCS) has been shown to improve force generation and control in single leg joints in healthy subjects and stroke survivors. However, it is unknown whether these effects also result in improved force production and coordination during walking. Here we

  19. Spectrochemical analysis of plutonium using direct current plasma emission spectrometry

    Morris, W.F.; Fadeff, S.K.; Torres, S.

    1983-01-01

    One year ago, LLNL was just completing the installation of a Direct Current Plasma (DCP) spectrometer for the analysis of Pu and Pu alloys. The installation was completed in December 1982 and has been utilized regularly for Pu analysis since then. This paper discusses the experience with the instrument and some data demonstrating its performance

  20. Physicochemical Properties of Biopolymer Hydrogels Treated by Direct Electric Current

    Żaneta Król

    2016-07-01

    Full Text Available The objective of this study was to evaluate the changes within the physicochemical properties of gelatine (2%; 4%; 8%, carrageenan (1.5%; 2%; 2.5% and sodium alginate (0.75%; 1%; 1.25% hydrogels with different sodium chloride concentrations that were triggered by applying direct current (DC of 400 mA for a duration of five minutes. There were three types of gels prepared for the purpose of the study: C, control; H, gels on the basis of hydrosols that were treated with DC; and G, gels treated with DC. In the course of the study, the authors carried out the following analyses: Texture Profile Analysis (TPA, Fourier Transform Infrared spectroscopy (FTIR, Scanning Electron Microscopy (SEM and Swelling Ratio (SR. Furthermore, the color and pH of hydrogels were measured. The FTIR spectra showed that the structures of gelatine, carrageenan and sodium alginate do not significantly change upon applying DC. The results of TPA, SR, color and pH measurement indicate that hydrogels’ properties are significantly dependent on the type of polymer, its concentration and the type of the gel. By changing those parameters, the characteristics of such gels can be additionally tuned, which extends their applicability, e.g., in the food industry. Moreover, the analysis revealed that SR of H gel gelatine after 72 h of storage was 1.84-times higher than SR of the control sample, which indicated that this gel may be considered as a possible component for wound dressing materials.

  1. Directed Motivational Currents: Using vision to create effective motivational pathways

    Christine Muir

    2013-10-01

    Full Text Available Vision, that is, the mental representation of the sensory experience of a future goal state (involving imagination and imagery, is currently at the forefront of motivational innovation, and in recent years it has been seen increasingly more often in the motivational tool kit of practicing language teachers. Theories such as Dörnyei’s L2 motivational self system have explored the power that creating effective visions can harness (see, e.g., Dörnyei & Kubanyiova, 2014 and when viewed in conjunction with other current research avenues, such as future time perspective and dynamic systems theory, vision offers exciting potential. A Directed Motivational Current is a new motivational construct that we suggest is capable of integrating many current theoretical strands with vision: It can be described as a motivational drive which energises long-term, sustained behaviour (such as language learning, and through placing vision and goals as critical central components within this construct, it offers real and practical motivational potential. In this conceptual paper, we first discuss current understandings of vision and of Directed Motivational Currents, and then analyse how they may be optimally integrated and employed to create effective motivational pathways in language learning environments.

  2. Logarithmic current-measuring transistor circuits

    Højberg, Kristian Søe

    1967-01-01

    Describes two transistorized circuits for the logarithmic measurement of small currents suitable for nuclear reactor instrumentation. The logarithmic element is applied in the feedback path of an amplifier, and only one dual transistor is used as logarithmic diode and temperature compensating...... transistor. A simple one-amplifier circuit is compared with a two-amplifier system. The circuits presented have been developed in connexion with an amplifier using a dual m.o.s. transistor input stage with diode-protected gates....

  3. Transcranial direct current stimulation as a treatment for auditory hallucinations.

    Sanne eKoops

    2015-03-01

    Full Text Available Auditory hallucinations (AH are a symptom of several psychiatric disorders, such as schizophrenia. In a significant minority of patients, AH are resistant to antipsychotic medication. Alternative treatment options for this medication-resistant group are scarce and most of them focus on coping with the hallucinations. Finding an alternative treatment that can diminish AH is of great importance.Transcranial direct current stimulation (tDCS is a safe and non-invasive technique that is able to directly influence cortical excitability through the application of very low electric currents. A 1-2 mA direct current is applied between two surface electrodes, one serving as the anode and the other as the cathode. Cortical excitability is increased in the vicinity of the anode and reduced near the cathode. The technique, which has only a few transient side effects and is cheap and portable, is increasingly explored as a treatment for neurological and psychiatric symptoms. It has shown efficacy on symptoms of depression, bipolar disorder, schizophrenia, Alzheimer’s disease, Parkinson’s disease, epilepsy and stroke. However, the application of tDCS as a treatment for AH is relatively new. This article provides an overview of the current knowledge in this field and provides guidelines for future research.

  4. Microstructure cantilever beam for current measurement

    M.T.E. Khan

    2010-01-01

    Full Text Available Most microelectromechanical systems (MEMS sensors are based on the microcantilever technology, which uses a broad range of design materials and structures. The benefit ofMEMStechnology is in developing devices with a lower cost, lower power consumption, higher performance and greater integration. A free-end cantilever beam with a magnetic material mass has been designed using MEMS software tools. The magnetic material was used to improve the sensitivity of the cantilever beam to an externally-applied magnetic field. The cantilever was designed to form a capacitance transducer, which consisted of variable capacitance where electrical and mechanical energies were exchanged. The aim of this paper was to analyse the system design of the microcantilever when subjected to a magnetic field produced by a current-carrying conductor. When the signal, a sinusoidal current with a constant frequency, was applied, the cantilever beam exhibited a vibration motion along the vertical axis when placed closer to the line current. This motion created corresponding capacitance changes and generated a voltage output proportional to the capacitive change in the signal-processing circuitry attached to the microcantilever. The equivalent massspring system theory was used to describe and analyse the effect of the natural frequency of the system vibrations and motion due to the applied magnetic field, in a single-degree of freedom. The main application of this microcantilever is in current measurements to develop a non-contact current sensor mote.

  5. Measurement of toroidal plasma current in RF heated helical plasmas

    Besshou, Sakae

    1993-01-01

    This report describes the measurement of toroidal plasma current by a semiflexible Rogowski coil in a helical vacuum chamber. A Rogowski coil measures the toroidal plasma current with a resolution of 0.1 kA, frequency range of up to 1 kHz and sensitivity of 6.5 x 10 -9 V · s/A. We measured the spontaneous toroidal plasma current (from -1.2 to +1.2 kA) under electron cyclotron resonance heating at 0.94 T toroidal field in the Heliotron-E device. We found that the measured direction of toroidal plasma current changes its sign as in the predicted behavior of a neoclassical diffusion-driven bootstrap current, depending on the horizontal position of the plasma column. We explain the observed plasma currents in terms of the compound phenomenon of an ohmic current and a neoclassical diffusion-driven current. The magnitude of the neoclassical current component is smaller than the value predicted by a collisionless neoclassical theory. (author)

  6. Wind measurement via direct detection lidar

    Afek, I.; Sela, N.; Narkiss, N.; Shamai, G.; Tsadka, S.

    2013-10-01

    Wind sensing Lidar is considered a promising technology for high quality wind measurements required for various applications such as hub height wind resource assessment, power curve measurements and advanced, real time, forward looking turbine control. Until recently, the only available Lidar technology was based on coherent Doppler shift detection, whose market acceptance has been slow primarily due to its exuberant price. Direct detection Lidar technology provides an alternative to remote sensing of wind by incorporating high precision measurement, a robust design and an affordable price tag.

  7. Frontal transcranial direct current stimulation (tDCS) abolishes list-method directed forgetting.

    Silas, Jonathan; Brandt, Karen R

    2016-03-11

    It is a point of controversy as to whether directed forgetting effects are a result of active inhibition or a change of context initiated by the instruction to forget. In this study we test the causal role of active inhibition in directed forgetting. By applying cathodal transcranial direct current stimulation (tDCS) over the right prefrontal cortex we suppressed cortical activity commonly associated with inhibitory control. Participants who underwent real brain stimulation before completing the directed forgetting paradigm showed no directed forgetting effects. Conversely, those who underwent sham brain stimulation demonstrated classical directed forgetting effects. We argue that these findings suggest that inhibition is the primary mechanism that results in directed forgetting costs and benefits. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  8. Multiday Transcranial Direct Current Stimulation Causes Clinically Insignificant Changes in Childhood Dystonia: A Pilot Study.

    Bhanpuri, Nasir H; Bertucco, Matteo; Young, Scott J; Lee, Annie A; Sanger, Terence D

    2015-10-01

    Abnormal motor cortex activity is common in dystonia. Cathodal transcranial direct current stimulation may alter cortical activity by decreasing excitability while anodal stimulation may increase motor learning. Previous results showed that a single session of cathodal transcranial direct current stimulation can improve symptoms in childhood dystonia. Here we performed a 5-day, sham-controlled, double-blind, crossover study, where we measured tracking and muscle overflow in a myocontrol-based task. We applied cathodal and anodal transcranial direct current stimulation (2 mA, 9 minutes per day). For cathodal transcranial direct current stimulation (7 participants), 3 subjects showed improvements whereas 2 showed worsening in overflow or tracking error. The effect size was small (about 1% of maximum voluntary contraction) and not clinically meaningful. For anodal transcranial direct current stimulation (6 participants), none showed improvement, whereas 5 showed worsening. Thus, multiday cathodal transcranial direct current stimulation reduced symptoms in some children but not to a clinically meaningful extent, whereas anodal transcranial direct current stimulation worsened symptoms. Our results do not support transcranial direct current stimulation as clinically viable for treating childhood dystonia. © The Author(s) 2015.

  9. Direct friction measurement in draw bead testing

    Olsson, David Dam; Bay, Niels; Andreasen, Jan Lasson

    2005-01-01

    The application of draw beads in sheet metal stamping ensures controlled drawing-in of flange parts. Lubrication conditions in draw beads are severe due to sliding under simultaneous bending. Based on the original draw bead test design by Nine [1] comprehensive studies of friction in draw beads...... have been reported in literature. A major drawback in all these studies is that friction is not directly measured, but requires repeated measurements of the drawing force with and without relative sliding between the draw beads and the sheet material. This implies two tests with a fixed draw bead tool...... and a freely rotating tool respectively, an approach, which inevitably implies large uncertainties due to scatter in the experimental conditions. In order to avoid this problem a new draw bead test is proposed by the authors measuring the friction force acting on the tool radius directly by a build...

  10. Direct measurement of the W boson width

    Abazov, V.M.; /Dubna, JINR; Abbott, B.; /Oklahoma U.; Abolins, M.; /Michigan State U.; Acharya, B.S.; /Tata Inst.; Adams, M.; /Illinois U., Chicago; Adams, T.; /Florida State U.; Aguilo, E.; /Alberta U. /Simon Fraser U. /McGill U.; Ahsan, M.; /Kansas State U.; Alexeev, G.D.; /Dubna, JINR; Alkhazov, G.; /St. Petersburg, INP; Alton, A.; /Michigan U. /Northeastern U.

    2009-09-01

    We present a direct measurement of the width of the W boson using the shape of the transverse mass distribution of W {yields} e{nu} candidates selected in 1 fb{sup -1} of data collected with the D0 detector at the Fermilab Tevatron collider in p{bar p} collisions at {radical}s = 1.96 TeV. We use the same methods and data sample that were used for our recently published W boson mass measurement, except for the modeling of the recoil, which is done with a new method based on a recoil library. Our result, 2.028 {+-} 0.072 GeV, is in agreement with the predictions of the standard model and is the most precise direct measurement result from a single experiment to date.

  11. Current and Future Research Directions in Requirements Engineering

    Cheng, Betty H. C.; Atlee, Joanne M.

    In this paper, we review current requirements engineering (RE) research and identify future research directions suggested by emerging software needs. First, we overview the state of the art in RE research. The research is considered with respect to technologies developed to address specific requirements tasks, such as elicitation, modeling, and analysis. Such a review enables us to identify mature areas of research, as well as areas that warrant further investigation. Next, we review several strategies for performing and extending RE research results, to help delineate the scope of future research directions. Finally, we highlight what we consider to be the “hot” current and future research topics, which aim to address RE needs for emerging systems of the future.

  12. The Philippine historical earthquakecatalog: its development, current stateand future directions

    Bautista, M. L. P.; Bautista, B. C.

    2004-01-01

    This report will trace the development of the historical earthquake catalog of the Philippines, assess its present state and recommend future research directions. The current Philippine historical earthquake catalog is culled from various catalogs, both global and local, that were developed since the first Philippine catalog by Perrey was published in 1860. While early global catalogs gave simple mention of earthquakes in the Philippines, more focused earthquake catalogs about the Philippines...

  13. Magnetic particle imaging: current developments and future directions

    Panagiotopoulos N

    2015-04-01

    of different theories and technical approaches on the way to the actual implementation of the basic concept of MPI have been seen in the last few years. Research groups around the world are working on different scanner geometries, from closed bore systems to single-sided scanners, and use reconstruction methods that are either based on actual calibration measurements or on theoretical models. This review aims at giving an overview of current developments and future directions in MPI about a decade after its first appearance. Keywords: magnetic particle imaging, superparamagnetic iron oxide nanoparticles, magnetic particle spectrometer, peripheral nerve stimulation, cardiovascular interventions

  14. Experimental study of anti-tumor activity of direct current

    Ito, Hisao; Hashimoto, Shozo

    1989-01-01

    The anti-tumor activity of direct current combined with radiation was studied. The experiments were performed with fibrosarcomas (FSA, NFSA) syngenetic to C3H mice. Direct current (0.6mA, 120min) alone was effective to reduce the tumor sizes, but could not cure the tumors. When the direct current therapy (DC therapy) was combined with radiation the DC therapy following radiation was more effective than that before radiation. Using TCD 50 assay, the DC therapy enhanced the effect of a single dose of radiation with the dose-modifying factor of 1.2. However, tumor control rates by the combination therapy were more improved at the smaller doses of radiation than at the larger ones. When the single DC therapy (0.6mA, 120min) was applied immediately after the first radiation of fractionated one the combination therapy still showed the enhanced effect. However, both DC therapy and the radiation therapy were divided in three fractions, and the DC therapy (0.6mA, 40min) was applied after each radiation. Tumor growth retardation by the combination therapy was no different from that by radiation alone. This result suggests that there might be a minimum required dose of coulombs to show the effect of the combination therapy. (author)

  15. A method for crack profiles identification in eddy current testing by the multi-directional scan

    Kojima, Fumio; Ikeda, Takuya; Nguyen, Doung

    2006-01-01

    This paper is concerned with a method for identification of crack shape in conducting materials. Multi-directional scanning strategies using Eddy Current Testing is performed for sizing complex natural crackings. Two dimensional measurements by means of multi-directional scan are used in a output least square identifications. (author)

  16. Field measurement on longshore current variation between Ratnagiri and Mangalore, west coast of India

    Chandramohan, P.; Nayak, B.U.; Anand, N.M.; SanilKumar, V.

    The daily measurements on longshore current velocity and direction were carried out at selected 12 stations along the coast between Ratnagiri and Mangalore, India. The directional wave data measured at Karwar were used to theoretically estimate...

  17. Starting characteristics of direct current motors powered by solar cells

    Singer, S.; Appelbaum, J.

    1989-01-01

    Direct current motors are used in photovoltaic systems. Important characteristics of electric motors are the starting to rated current and torque ratios. These ratios are dictated by the size of the solar cell array and are different for the various dc motor types. Discussed here is the calculation of the starting to rated current ratio and starting to rated torque ratio of the permanent magnet, and series and shunt excited motors when powered by solar cells for two cases: with and without a maximum-power-point-tracker (MPPT) included in the system. Comparing these two cases, one gets a torque magnification of about 3 for the permanent magnet motor and about 7 for other motor types. The calculation of the torques may assist the PV system designer to determine whether or not to include an MPPT in the system.

  18. Determinants of the electric field during transcranial direct current stimulation

    Opitz, Alexander; Paulus, Walter; Will, Susanne

    2015-01-01

    Transcranial direct current stimulation (tDCS) causes a complex spatial distribution of the electric current flow in the head which hampers the accurate localization of the stimulated brain areas. In this study we show how various anatomical features systematically shape the electric field...... over the motor cortex in small steps to examine the resulting changes of the electric field distribution in the underlying cortex. We examined the effect of skull thickness and composition on the passing currents showing that thinner skull regions lead to higher electric field strengths. This effect...... fluid and the skull, the gyral depth and the distance to the anode and cathode. These factors account for up to 50% of the spatial variation of the electric field strength. Further, we demonstrate that individual anatomical factors can lead to stimulation "hotspots" which are partly resistant...

  19. Lightning Current Measurement with Fiber-Optic Sensor

    Nguyen, Truong X.; Ely, Jay J.; Szatkowski, George N.; Mata, Carlos T.; Mata, Angel G.; Snyder, Gary P.

    2014-01-01

    A fiber-optic current sensor is successfully developed with many potential applications for electric current measurement. Originally developed for in-flight lightning measurement, the sensor utilizes Faraday Effect in an optical fiber. The Faraday Effect causes linear light polarization in a fiber to rotate when the fiber is exposed to a magnetic field. The polarization change is detected using a reflective polarimetric scheme. Forming fiber loops and applying Ampere's law, measuring the total light rotation results in the determination of the total current enclosed. The sensor is conformable to complex structure geometry. It is also non-conductive and immune to electromagnetic interference, saturation or hysteresis. Installation is non-intrusive, and the sensor can be safely routed through flammable areas. Two similar sensor systems are described in this paper. The first system operates at 1310nm laser wavelength and is capable of measuring approximately 300 A - 300 kA, a 60 dB range. Laboratory validation results of aircraft lighting direct and in-direct effect current amplitudes are reported for this sensor. The second system operates at 1550nm wavelength and can measure about 400 A - 400 kA. Triggered-lightning measurement data are presented for this system. Good results are achieved in all cases.

  20. A Fiber-Optic Aircraft Lightning Current Measurement Sensor

    Nguyen, Truong X.; Ely, Jay J.; Szatkowski, George N.

    2013-01-01

    A fiber-optic current sensor based on the Faraday Effect is developed for aircraft installations. It can measure total lightning current amplitudes and waveforms, including continuing current. Additional benefits include being small, lightweight, non-conducting, safe from electromagnetic interference, and free of hysteresis and saturation. The Faraday Effect causes light polarization to rotate in presence of magnetic field in the direction of light propagation. Measuring the total induced light polarization change yields the total current enclosed. The system operates at 1310nm laser wavelength and can measure approximately 300 A - 300 kA, a 60 dB range. A reflective polarimetric scheme is used, where the light polarization change is measured after a round-trip propagation through the fiber. A two-detector setup measures the two orthogonal polarizations for noise subtraction and improved dynamic range. The current response curve is non-linear and requires a simple spline-fit correction. Effects of high current were achieved in laboratory using combinations of multiple fiber and wire loops. Good result comparisons against reference sensors were achieved up to 300 kA. Accurate measurements on a simulated aircraft fuselage and an internal structure illustrate capabilities that maybe difficult with traditional sensors. Also tested at a commercial lightning test facility from 20 kA to 200 kA, accuracy within 3-10% was achieved even with non-optimum setups.

  1. Fluxgate Magnetic Sensor and Its Application for Current Measurement

    Mitra-Djamal

    2007-01-01

    Conventionally electric current can be measured by connecting the instrument serially on the circuit. This method has disadvantage because its disturb the measured current flow. By using a magnetic sensor, current can be measured without disturbing the current flow, because it just measures the magnetic field of the measured current. This paper shows the use of fluxgate magnetic sensor for current measurement. It is shown that the sensor can measure widely range of current with resolution ≤ 2 %. (author)

  2. Direct amplitude detuning measurement with ac dipole

    S. White

    2013-07-01

    Full Text Available In circular machines, nonlinear dynamics can impact parameters such as beam lifetime and could result in limitations on the performance reach of the accelerator. Assessing and understanding these effects in experiments is essential to confirm the accuracy of the magnetic model and improve the machine performance. A direct measurement of the machine nonlinearities can be obtained by characterizing the dependency of the tune as a function of the amplitude of oscillations (usually defined as amplitude detuning. The conventional technique is to excite the beam to large amplitudes with a single kick and derive the tune from turn-by-turn data acquired with beam position monitors. Although this provides a very precise tune measurement it has the significant disadvantage of being destructive. An alternative, nondestructive way of exciting large amplitude oscillations is to use an ac dipole. The perturbation Hamiltonian in the presence of an ac dipole excitation shows a distinct behavior compared to the free oscillations which should be correctly taken into account in the interpretation of experimental data. The use of an ac dipole for direct amplitude detuning measurement requires careful data processing allowing one to observe the natural tune of the machine; the feasibility of such a measurement is demonstrated using experimental data from the Large Hadron Collider. An experimental proof of the theoretical derivations based on measurements performed at injection energy is provided as well as an application of this technique at top energy using a large number of excitations on the same beam.

  3. Safety of Transcranial Direct Current Stimulation: Evidence Based Update 2016.

    Bikson, Marom; Grossman, Pnina; Thomas, Chris; Zannou, Adantchede Louis; Jiang, Jimmy; Adnan, Tatheer; Mourdoukoutas, Antonios P; Kronberg, Greg; Truong, Dennis; Boggio, Paulo; Brunoni, André R; Charvet, Leigh; Fregni, Felipe; Fritsch, Brita; Gillick, Bernadette; Hamilton, Roy H; Hampstead, Benjamin M; Jankord, Ryan; Kirton, Adam; Knotkova, Helena; Liebetanz, David; Liu, Anli; Loo, Colleen; Nitsche, Michael A; Reis, Janine; Richardson, Jessica D; Rotenberg, Alexander; Turkeltaub, Peter E; Woods, Adam J

    2016-01-01

    This review updates and consolidates evidence on the safety of transcranial Direct Current Stimulation (tDCS). Safety is here operationally defined by, and limited to, the absence of evidence for a Serious Adverse Effect, the criteria for which are rigorously defined. This review adopts an evidence-based approach, based on an aggregation of experience from human trials, taking care not to confuse speculation on potential hazards or lack of data to refute such speculation with evidence for risk. Safety data from animal tests for tissue damage are reviewed with systematic consideration of translation to humans. Arbitrary safety considerations are avoided. Computational models are used to relate dose to brain exposure in humans and animals. We review relevant dose-response curves and dose metrics (e.g. current, duration, current density, charge, charge density) for meaningful safety standards. Special consideration is given to theoretically vulnerable populations including children and the elderly, subjects with mood disorders, epilepsy, stroke, implants, and home users. Evidence from relevant animal models indicates that brain injury by Direct Current Stimulation (DCS) occurs at predicted brain current densities (6.3-13 A/m(2)) that are over an order of magnitude above those produced by conventional tDCS. To date, the use of conventional tDCS protocols in human trials (≤40 min, ≤4 milliamperes, ≤7.2 Coulombs) has not produced any reports of a Serious Adverse Effect or irreversible injury across over 33,200 sessions and 1000 subjects with repeated sessions. This includes a wide variety of subjects, including persons from potentially vulnerable populations. Copyright © 2016 Elsevier Inc. All rights reserved.

  4. Automatic adjustment of bias current for direct current superconducting quantum interference device

    Makie-Fukuda, K.; Hotta, M.; Okajima, K.; Kado, H.

    1993-01-01

    A new method of adjusting the bias current of dc superconducting quantum interference device (SQUID) is described. It is shown that the signal-to-noise ratio of a SQUID magnetometer connected in a flux-locked loop configuration is proportional to the second harmonic of the output signal from the SQUID. A circuit configuration that can automatically optimize a SQUID's bias current by measuring this second harmonic and adjusting the bias current accordingly is proposed

  5. Transcutaneous Spinal Direct Current Stimulation (tsDCS

    Filippo eCogiamanian

    2012-07-01

    Full Text Available In the past ten years renewed interest has centered on non-invasive transcutaneous weak direct currents applied over the scalp to modulate cortical excitability (brain polarization or transcranial direct current stimulation, tDCS. Extensive literature shows that tDCS induces marked changes in cortical excitability that outlast stimulation.Aiming at developing a new, non invasive, approach to spinal cord neuromodulation we assessed the after-effects of thoracic transcutaneous spinal DC stimulation (tsDCS on somatosensory potentials (SEPs evoked in healthy subjects by posterior tibial nerve (PTN stimulation. Our findings showed that thoracic anodal tsDCS depresses the cervico-medullary PTN-SEP component (P30 without eliciting adverse effects. tsDCS also modulates post-activation H-reflex dynamics. Later works further confirmed that transcutaneous electric fields modulate spinal cord function. Subsequent studies in our laboratory showed that tsDCS modulates the flexion reflex in the human lower limb. Besides influencing the laser evoked potentials, tsDCS increases pain tolerance in healthy subjects. Hence, though the underlying mechanisms remain speculative, tsDCS modulates activity in lemniscal, spinothalamic and segmental motor systems.Here we review currently available experimental evidence that non-invasive spinal cord stimulation influences spinal function in humans and argue that, by focally modulating spinal excitability, tsDCS could provide a novel therapeutic tool complementary to drugs and invasive spinal cord stimulation in managing various pathologic conditions, including pain.

  6. Fiber-Optic Sensor for Aircraft Lightning Current Measurement

    Nguyen, Truong X.; Ely, Jay J.; Szatkowski, George G.; Mata, Carlos T.; Mata, Angel G.; Snyder, Gary P.

    2012-01-01

    An electric current sensor based on Faraday rotation effect in optical fiber was developed for measuring aircraft lightning current. Compared to traditional sensors, the design has many advantages including the ability to measure total current and to conform to structure geometries. The sensor is also small, light weight, non-conducting, safe from interference, and free of hysteresis and saturation. Potential applications include characterization of lightning current waveforms, parameters and paths, and providing environmental data for aircraft certifications. In an optical fiber as the sensing medium, light polarization rotates when exposed to a magnetic field in the direction of light propagation. By forming closed fiber loops around a conductor and applying Ampere s law, measuring the total light rotation yields the enclosed current. A reflective polarimetric scheme is used, where polarization change is measured after the polarized light travels round-trip through the sensing fiber. The sensor system was evaluated measuring rocket-triggered lightning over the 2011 summer. Early results compared very well against a reference current shunt resistor, demonstrating the sensor s accuracy and feasibility in a lightning environment. While later comparisons show gradually increasing amplitude deviations for an undetermined cause, the overall waveforms still compared very well.

  7. Current and Emerging Directions in the Treatment of Eating Disorders

    Tiffany A. Brown

    2012-01-01

    Full Text Available Eating disorders are a significant source of psychiatric morbidity in young women and demonstrate high comorbidity with mood, anxiety, and substance use disorders. Thus, clinicians may encounter eating disorders in the context of treating other conditions. This review summarizes the efficacy of current and emerging treatments for anorexia nervosa (AN, bulimia nervosa (BN, and binge eating disorder (BED. Treatment trials were identified using electronic and manual searches and by reviewing abstracts from conference proceedings. Family based therapy has demonstrated superiority for adolescents with AN but no treatment has established superiority for adults. For BN, both 60 mg fluoxetine and cognitive behavioral therapy (CBT have well-established efficacy. For BED, selective serotonin reuptake inhibitors, CBT, and interpersonal psychotherapy have demonstrated efficacy. Emerging directions for AN include investigation of the antipsychotic olanzapine and several novel psychosocial treatments. Future directions for BN and BED include increasing CBT disseminability, targeting affect regulation, and individualized stepped-care approaches.

  8. Joint Inversion of Direct Current Resistivity and Seismic Refraction Data

    Kurt, B.B.

    2007-01-01

    In this study, I assumed the underground consist of horizontal layers. I developed one-dimensional (1D) Direct Current Resistivity (DCR) and seismic refraction inversion code using MATLAB package and attempt to find velocity, resistivity and depth of the layers. The code uses damped least square technique. The code can do inversion on DCR and seismic data either individually or jointly. I tested the joint inversion code on synthetic data. Eventually, I saw that the result of joint inversion is better than the result of individual inversions. The joint inversion found depth of models of each layer and, in addition, velocity and resistivity closer to real values

  9. Is direct measurement of time possible?

    Reynolds, Thomas

    2017-08-01

    Is direct measurement of time possible? The answer to this question may depend upon how one understands time. Is time an essential constituent of physical reality? Or is what scientists are talking about when they use the symbol ‘t’ or the word ‘time’ an human cultural construct, as the Chief of the USA NIST Divisions of Time and Frequency and of Quantum Physics has suggested. Few aspects of physics do not reference activity to time, but many discussions within either view of time seem to use one same, largely traditional, language of time. Briefly considering the question of measurement, including from a formal measure-theoretic point of view, clarifies the situation.

  10. Transcranial direct-current stimulation as treatment in epilepsy.

    Gschwind, Markus; Seeck, Margitta

    2016-12-01

    Neuromodulation (NM) is a complementary therapy for patients with drug-resistant epilepsy. Vagal nerve stimulation and deep brain stimulation of the anterior thalamus are established techniques and have shown their efficacy in lowering seizure frequency, but they are invasive and rarely render patients seizure-free. Non-invasive NM techniques are therefore increasingly investigated in a clinical context. Areas covered: Current knowledge about transcranial direct-current stimulation (tDCS) and other non-invasive NM in patients with epilepsy, based on the available animal and clinical studies from PubMed search. Expert commentary: tDCS modulates neuronal membrane potentials, and consequently alters cortical excitability. Cathodal stimulation leads to cortical inhibition, which is of particular importance in epilepsy treatment. The antiepileptic efficacy is promising but still lacks systematic studies. The beneficial effect, seen in ~20%, outlasts the duration of stimulation, indicating neuronal plasticity and is therefore of great interest to obtain long-term effects.

  11. Transcranial cerebellar direct current stimulation and transcutaneous spinal cord direct current stimulation as innovative tools for neuroscientists

    Priori, Alberto; Ciocca, Matteo; Parazzini, Marta; Vergari, Maurizio; Ferrucci, Roberta

    2014-01-01

    Two neuromodulatory techniques based on applying direct current (DC) non-invasively through the skin, transcranial cerebellar direct current stimulation (tDCS) and transcutaneous spinal DCS, can induce prolonged functional changes consistent with a direct influence on the human cerebellum and spinal cord. In this article we review the major experimental works on cerebellar tDCS and on spinal tDCS, and their preliminary clinical applications. Cerebellar tDCS modulates cerebellar motor cortical inhibition, gait adaptation, motor behaviour, and cognition (learning, language, memory, attention). Spinal tDCS influences the ascending and descending spinal pathways, and spinal reflex excitability. In the anaesthetised mouse, DC stimulation applied under the skin along the entire spinal cord may affect GABAergic and glutamatergic systems. Preliminary clinical studies in patients with cerebellar disorders, and in animals and patients with spinal cord injuries, have reported beneficial effects. Overall the available data show that cerebellar tDCS and spinal tDCS are two novel approaches for inducing prolonged functional changes and neuroplasticity in the human cerebellum and spinal cord, and both are new tools for experimental and clinical neuroscientists. PMID:24907311

  12. Combined Dextroamphetamine and Transcranial Direct Current Stimulation in Poststroke Aphasia.

    Keser, Zafer; Dehgan, Michelle Weber; Shadravan, Shaparak; Yozbatiran, Nuray; Maher, Lynn M; Francisco, Gerard E

    2017-10-01

    There is a growing need for various effective adjunctive treatment options for speech recovery after stroke. A pharmacological agent combined with noninvasive brain stimulation has not been previously reported for poststroke aphasia recovery. In this "proof of concept" study, we aimed to test the safety of a combined intervention consisting of dextroamphetamine, transcranial direct current stimulation, and speech and language therapy in subjects with nonfluent aphasia. Ten subjects with chronic nonfluent aphasia underwent two experiments where they received dextroamphetamine or placebo along with transcranial direct current stimulation and speech and language therapy on two separate days. The Western Aphasia Battery-Revised was used to monitor changes in speech performance. No serious adverse events were observed. There was no significant increase in blood pressure with amphetamine or deterioration in speech and language performance. Western Aphasia Battery-Revised aphasia quotient and language quotient showed a statistically significant increase in the active experiment. Comparison of proportional changes of aphasia quotient and language quotient in active experiment with those in placebo experiment showed significant difference. We showed that the triple combination therapy is safe and implementable and seems to induce positive changes in speech and language performance in the patients with chronic nonfluent aphasia due to stroke.

  13. Consumer Mobile Health Apps: Current State, Barriers, and Future Directions.

    Kao, Cheng-Kai; Liebovitz, David M

    2017-05-01

    This paper discusses the current state, barriers, and future directions of consumer-facing applications (apps). There are currently more than 165,000 mobile health apps publicly available in major app stores, the vast majority of which are designed for patients. The top 2 categories are wellness management and disease management apps, whereas other categories include self-diagnosis, medication reminder, and electronic patient portal apps. Apps specific to physical medicine and rehabilitation also are reviewed. These apps have the potential to provide low-cost, around-the-clock access to high-quality, evidence-based health information to end users on a global scale. However, they have not yet lived up to their potential due to multiple barriers, including lack of regulatory oversight, limited evidence-based literature, and concerns of privacy and security. The future directions may consist of improving data integration into the health care system, an interoperable app platform allowing access to electronic health record data, cloud-based personal health record across health care networks, and increasing app prescription by health care providers. For consumer mobile health apps to fully contribute value to health care delivery and chronic disease management, all stakeholders within the ecosystem must collaborate to overcome the significant barriers. Copyright © 2017 American Academy of Physical Medicine and Rehabilitation. Published by Elsevier Inc. All rights reserved.

  14. Measuring Rock-Fluid Adhesion Directly

    Tadmor, R.

    2017-12-01

    We show how to measure directly solid-liquid adhesion. We consider the normal adhesion, the work adhesion, and the lateral adhesion. The technique at the center of the method is Centrifugal Adhesion Balance (CAB) which allows coordinated manipulation of normal and lateral forces. For example: 1. It allows to induce an increase in the normal force which pulls on a liquid drop while keeping zero lateral force. This method mimics a drop that is subjected to a gravitational force that is gradually increasing. 2. It allows to increase the lateral force at zero normal force, mimicking zero gravity. From this one can obtain additional solid-liquid interaction parameters. When performing work of adhesion measurements, the values obtained are independent of drop size and are in agreement with theoretical predictions.

  15. Transcranial Direct Current Stimulation: Considerations for Research in Adolescent Depression

    Jonathan C. Lee

    2017-06-01

    Full Text Available Adolescent depression is a prevalent disorder with substantial morbidity and mortality. Current treatment interventions do not target relevant pathophysiology and are frequently ineffective, thereby leading to a substantial burden for individuals, families, and society. During adolescence, the prefrontal cortex undergoes extensive structural and functional changes. Recent work suggests that frontolimbic development in depressed adolescents is delayed or aberrant. The judicious application of non-invasive brain stimulation techniques to the prefrontal cortex may present a promising opportunity for durable interventions in adolescent depression. Transcranial direct current stimulation (tDCS applies a low-intensity, continuous current that alters cortical excitability. While this modality does not elicit action potentials, it is thought to manipulate neuronal activity and neuroplasticity. Specifically, tDCS may modulate N-methyl-d-aspartate receptors and L-type voltage-gated calcium channels and effect changes through long-term potentiation or long-term depression-like mechanisms. This mini-review considers the neurobiological rationale for developing tDCS protocols in adolescent depression, reviews existing work in adult mood disorders, surveys the existing tDCS literature in adolescent populations, reviews safety studies, and discusses distinct ethical considerations in work with adolescents.

  16. Verification of the directivity index and other measures of directivity in predicting directional benefit

    Dittberner, Andrew; Bentler, Ruth

    2005-09-01

    The relationship between various directivity measures and subject performance with directional microphone hearing aids was determined. Test devices included first- and second-order directional microphones. Recordings of sentences and noise (Hearing in Noise Test, HINT) were made through each test device in simple, complex, and anisotropic background noise conditions. Twenty-six subjects, with normal hearing, were administered the HINT test recordings, and directional benefit was computed. These measures were correlated to theoretical, free-field, and KEMAR DI values, as well as front-to-back ratios, in situ SNRs, and a newly proposed Db-SNR, wherein a predictive value of the SNR improvement is calculated as a function of the noise source incidence. The different predictive scores showed high correlation to the measured directional benefit scores in the complex (diffuse-like) background noise condition (r=0.89-0.97, pThe Db-SNR approach and the in situ SNR measures provided excellent prediction of subject performance in all background noise conditions (0.85-0.97, pthe predictive measures could account for the effects of reverberation on the speech signal (r=0.35-0.40, p<0.05).

  17. Culture, mind, and the brain: current evidence and future directions.

    Kitayama, Shinobu; Uskul, Ayse K

    2011-01-01

    Current research on culture focuses on independence and interdependence and documents numerous East-West psychological differences, with an increasing emphasis placed on cognitive mediating mechanisms. Lost in this literature is a time-honored idea of culture as a collective process composed of cross-generationally transmitted values and associated behavioral patterns (i.e., practices). A new model of neuro-culture interaction proposed here addresses this conceptual gap by hypothesizing that the brain serves as a crucial site that accumulates effects of cultural experience, insofar as neural connectivity is likely modified through sustained engagement in cultural practices. Thus, culture is "embrained," and moreover, this process requires no cognitive mediation. The model is supported in a review of empirical evidence regarding (a) collective-level factors involved in both production and adoption of cultural values and practices and (b) neural changes that result from engagement in cultural practices. Future directions of research on culture, mind, and the brain are discussed.

  18. Direct-current nanogenerator driven by ultrasonic waves.

    Wang, Xudong; Song, Jinhui; Liu, Jin; Wang, Zhong Lin

    2007-04-06

    We have developed a nanowire nanogenerator that is driven by an ultrasonic wave to produce continuous direct-current output. The nanogenerator was fabricated with vertically aligned zinc oxide nanowire arrays that were placed beneath a zigzag metal electrode with a small gap. The wave drives the electrode up and down to bend and/or vibrate the nanowires. A piezoelectric-semiconducting coupling process converts mechanical energy into electricity. The zigzag electrode acts as an array of parallel integrated metal tips that simultaneously and continuously create, collect, and output electricity from all of the nanowires. The approach presents an adaptable, mobile, and cost-effective technology for harvesting energy from the environment, and it offers a potential solution for powering nanodevices and nanosystems.

  19. Current approaches and future directions in the treatment of leprosy

    Worobec SM

    2012-08-01

    Full Text Available Sophie M WorobecDepartment of Dermatology, College of Medicine, University of Illinois at Chicago, Chicago, Illinois, USAAbstract: This review surveys current treatments and future treatment trends in leprosy from a clinical perspective. The World Health Organization provides a multidrug treatment regimen that targets the Mycobacterium leprae bacillus which causes leprosy. Several investigational drugs are available for the treatment of drug-resistant M. leprae. Future directions in leprosy treatment will focus on: the molecular signaling mechanism M. leprae uses to avoid triggering an immune response; prospective studies of the side effects experienced during multiple-drug therapy; recognition of relapse rates post-completion of designated treatments; combating multidrug resistance; vaccine development; development of new diagnostic tests; and the implications of the recent discovery of a genetically distinct leprosy-causing bacillus, Mycobacterium lepromatosis.Keywords: epidemiology, leprosy, Hansen’s disease, multidrug resistance, multidrug therapy

  20. High-voltage direct-current circuit breakers

    Yoshioka, Y.; Hirasawa, K.

    1991-01-01

    This paper reports that in 1954 the first high-voltage direct-current (HVDC) transmission system was put into operation between Gotland and the mainland of Sweden. Its system voltage and capacity were 100 kV and 20 MW, respectively. Since then many HVDC transmission systems have been planned, constructed, or commissioned in more than 30 places worldwide, and their total capacity is close to 40 GW. Most systems commissioned to date are two-terminal schemes, and HVDC breakers are not yet used in the high-potential main circuit of those systems, because the system is expected to perform well using only converter/inverter control even at a fault stage of the transmission line. However, even in a two-terminal scheme there are not a few merits in using an HVDC breaker when the system has two parallel transmission lines, that is, when it is a double-circuit system

  1. Current control for magnetized plasma in direct-current plasma-immersion ion implantation

    Tang Deli; Chu, Paul K.

    2003-01-01

    A method to control the ion current in direct-current plasma-immersion ion implantation (PIII) is reported for low-pressure magnetized inductively coupled plasma. The ion current can be conveniently adjusted by applying bias voltage to the conducting grid that separates plasma formation and implantation (ion acceleration) zones without the need to alter the rf input power, gas flux, or other operating conditions. The ion current that diminishes with an increase in grid bias in magnetized plasmas can be varied from 48 to 1 mA by increasing the grid voltage from 0 to 70 V at -50 kV sample bias and 0.5 mTorr hydrogen pressure. High implantation voltage and monoenergetic immersion implantation can now be achieved by controlling the ion current without varying the macroscopic plasma parameters. The experimental results and interpretation of the effects are presented in this letter. This technique is very attractive for PIII of planar samples that require on-the-fly adjustment of the implantation current at high implantation voltage but low substrate temperature. In some applications such as hydrogen PIII-ion cut, it may obviate the need for complicated sample cooling devices that must work at high voltage

  2. Novel methods to optimize the effects of transcranial direct current stimulation: a systematic review of transcranial direct current stimulation patents.

    Malavera, Alejandra; Vasquez, Alejandra; Fregni, Felipe

    2015-01-01

    Transcranial direct current stimulation (tDCS) is a neuromodulatory technique that has been extensively studied. While there have been initial positive results in some clinical trials, there is still variability in tDCS results. The aim of this article is to review and discuss patents assessing novel methods to optimize the use of tDCS. A systematic review was performed using Google patents database with tDCS as the main technique, with patents filling date between 2010 and 2015. Twenty-two patents met our inclusion criteria. These patents attempt to address current tDCS limitations. Only a few of them have been investigated in clinical trials (i.e., high-definition tDCS), and indeed most of them have not been tested before in human trials. Further clinical testing is required to assess which patents are more likely to optimize the effects of tDCS. We discuss the potential optimization of tDCS based on these patents and the current experience with standard tDCS.

  3. Mechanisms and Effects of Transcranial Direct Current Stimulation

    Giordano, James; Bikson, Marom; Kappenman, Emily S.; Clark, Vincent P.; Coslett, H. Branch; Hamblin, Michael R.; Hamilton, Roy; Jankord, Ryan; Kozumbo, Walter J.; McKinley, R. Andrew; Nitsche, Michael A.; Reilly, J. Patrick; Richardson, Jessica; Wurzman, Rachel

    2017-01-01

    The US Air Force Office of Scientific Research convened a meeting of researchers in the fields of neuroscience, psychology, engineering, and medicine to discuss most pressing issues facing ongoing research in the field of transcranial direct current stimulation (tDCS) and related techniques. In this study, we present opinions prepared by participants of the meeting, focusing on the most promising areas of research, immediate and future goals for the field, and the potential for hormesis theory to inform tDCS research. Scientific, medical, and ethical considerations support the ongoing testing of tDCS in healthy and clinical populations, provided best protocols are used to maximize safety. Notwithstanding the need for ongoing research, promising applications include enhancing vigilance/attention in healthy volunteers, which can accelerate training and support learning. Commonly, tDCS is used as an adjunct to training/rehabilitation tasks with the goal of leftward shift in the learning/treatment effect curves. Although trials are encouraging, elucidating the basic mechanisms of tDCS will accelerate validation and adoption. To this end, biomarkers (eg, clinical neuroimaging and findings from animal models) can support hypotheses linking neurobiological mechanisms and behavioral effects. Dosage can be optimized using computational models of current flow and understanding dose–response. Both biomarkers and dosimetry should guide individualized interventions with the goal of reducing variability. Insights from other applied energy domains, including ionizing radiation, transcranial magnetic stimulation, and low-level laser (light) therapy, can be prudently leveraged. PMID:28210202

  4. Improving CANDU annunciation - Current R and D and future directions

    Lupton, L.R.; Feher, M.P.; Davey, E.C.; Guo, K.Q.; Bhuiyan, S.H.

    1994-01-01

    Annunciation is used to ensure that control room staff are promptly alerted to important changes in plant conditions that may impact on safety and production goals. We are carrying out research and development to improve CANDU annunciation, in partnership with Canadian CANDU utility and design organizations. The main goal is to solve the ''information overload'' problem that occurs during major plant upsets, while providing operators with annunciation information needed to prevent, mitigate, and accommodate plant disturbances. To data, a set of annunciation concepts has been developed based on operational needs in a complex supervisory control environment. A prototype annunciation system has been developed and demonstrated with Point Lepreau Generating Station operations staff. Preliminary evaluations show that the system has the potential to solve many of the current problems associated with upset management. Further evaluation of this system is planned for 1994/95. This paper summarizes the project, including the current status, lessons learned to data, future directions of the research, and implementation by plants. (author). 9 refs, 3 figs, 1 tab

  5. Fundamental properties of field emission-driven direct current microdischarges

    Rumbach, Paul; Go, David B.

    2012-01-01

    For half a century, it has been known that the onset of field emission in direct current microdischarges with gap sizes less than 10 μm can lead to breakdown at applied voltages far less than predicted by Paschen's law. It is still unclear how field emission affects other fundamental plasma properties at this scale. In this work, a one-dimensional fluid model is used to predict basic scaling laws for fundamental properties including ion density, electric field due to space charge, and current-voltage relations in the pre-breakdown regime. Computational results are compared with approximate analytic solutions. It is shown that field emission provides an abundance of cathode electrons, which in turn create large ion concentrations through ionizing collisions well before Paschen's criterion for breakdown is met. Breakdown due to ion-enhanced field emission occurs when the electric field due to space charge becomes comparable to the applied electric field. Simple scaling analysis of the 1D Poisson equation demonstrates that an ion density of n + ≈ 0.1V A ε 0 /qd 2 is necessary to significantly distort the electric field. Defining breakdown in terms of this critical ion density leads analytically to a simple, effective secondary emission coefficient γ ′ of the same mathematical form initially suggested by Boyle and Kisliuk [Phys. Rev. 97, 255 (1955)].

  6. A sensor element for direct radiation measurement

    Bajons, P.; Wernhart, U.; Zeiler, H. [University of Vienna (Austria). Institut of Material Physics

    1998-08-01

    A combination of a photodiode with a nonimaging light concentrator is developed to perform measurements of the direct solar radiation component. A prototype composed of low price elements is taken as a starting point to discuss the problems which must be faced when calibrating such sensors. By this the influence of the angle of incidence and spectral distribution (caused by different air mass or varying degree of clearness) of the incident radiation on the behavior of the system is studied. The readings are compared to the calculated (global minus diffuse) readings obtained from two standard star pyranometers. Finally the possibilities for increasing the accuracy of the sensor element and for applying the device are discussed. (author)

  7. Pediatric neurology training in Canada: current status and future directions.

    Doja, Asif

    2012-05-01

    Child neurology training in Canada has changed considerably over time, with increasing requirements for standardized teaching of the fundamentals of child neurology and the CanMEDS competencies. We sought to determine the current status of child neurology training in Canada as well future directions for training. A web-based survey was sent to program directors (PD's) of active pediatric neurology training programs. General questions about the programs were asked, as well as about success at the Royal College of Physicians and Surgeons of Canada (RCPSC) exam, breakdown of rotations, views on CanMEDS roles and questions on the future of pediatric neurology. 9/9 PD's completed the survey. 96.5% of all trainees successfully passed their RCPSC exam from 2001-2006. Breakdowns of the number and type of rotations for each year of training were provided. All CanMEDS roles were deemed to be important by PD's and programs have developed unique strategies to teach and assess these roles.92.6% of trainees chose to go into academic practice, with the most popular subspecialty being epilepsy. All PD's favour joint training sessions particularly for neurogenetics and neuromuscular disease. Overall, PD's suggest recruitment for future child neurologists at the medical student level but are divided as to whether we are currently training too few or too many child neurologists. This survey provides a view of the current state of pediatric neurology training in Canada and suggestions for further development of post-graduate training. In particular, attention should be given to joint educational programs as well as urgently assessing the manpower needs of child neurologists.

  8. Osmocapsules for direct measurement of osmotic strength.

    Kim, Shin-Hyun; Lee, Tae Yong; Lee, Sang Seok

    2014-03-26

    Monodisperse microcapsules with ultra-thin membranes are microfluidically designed to be highly sensitive to osmotic pressure, thereby providing a tool for the direct measurement of the osmotic strength. To make such osmocapsules, water-in-oil-in-water double-emulsion drops with ultra-thin shells are prepared as templates through emulsification of core-sheath biphasic flow in a capillary microfluidic device. When photocurable monomers are used as the oil phase, the osmocapsules are prepared by in-situ photopolymerization of the monomers, resulting in semipermeable membranes with a relatively large ratio of membrane thickness to capsule radius, approximately 0.02. These osmocapsules are buckled by the outward flux of water when they are subjected to a positive osmotic pressure difference above 125 kPa. By contrast, evaporation-induced consolidation of middle-phase containing polymers enables the production of osmocapsules with a small ratio of membrane thickness to capsule radius of approximately 0.002. Such an ultra-thin membrane with semi-permeability makes the osmocapsules highly sensitive to osmotic pressure; a positive pressure as small as 12.5 kPa induces buckling of the capsules. By employing a set of distinct osmocapsules confining aqueous solutions with different osmotic strengths, the osmotic strength of unknown solutions can be estimated through observation of the capsules that are selectively buckled. This approach provides the efficient measurement of the osmotic strength using only a very small volume of liquid, thereby providing a useful alternative to other measurement methods which use complex setups. In addition, in-vivo measurement of the osmotic strength can be potentially accomplished by implanting these biocompatible osmocapsules into tissue, which is difficult to achieve using conventional methods. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  9. Fiber-Optic Current Sensor Validation with Triggered Lightning Measurements

    Nguyen, Truong X.; Ely, Jay J.; Szatkowski, George N.; Mata, Carlos T.; Mata, Angel G.; Snyder, Gary P.

    2013-01-01

    A fiber optic current sensor based on the Faraday Effect is developed that is highly suitable for aircraft installation and can measure total current enclosed in a fiber loop down to DC. Other attributes include being small, light-weight, non-conducting, safe from electromagnetic interference, and free of hysteresis and saturation. The Faraday Effect causes light polarization to rotate when exposed to a magnetic field in the direction of light propagation. Measuring the induced light polarization rotation in fiber loops yields the total current enclosed. Two sensor systems were constructed and installed at Camp Blanding, Florida, measuring rocket-triggered lightning. The systems were similar in design but with different laser wavelengths, sensitivities and ranges. Results are compared to a shunt resistor as reference. The 850nm wavelength system tested in summer 2011 showed good result comparison early. However, later results showed gradual amplitude increase with time, attributed to corroded connections affecting the 50-ohm output termination. The 1550nm system also yielded good results in the summer 2012. The successful measurements demonstrate the fiber optic sensor's accuracies in capturing real lightning currents, and represent an important step toward future aircraft installation.

  10. NEWSdm: Nuclear Emulsions for WIMP Search with directional measurement

    Di Crescenzo A.

    2017-01-01

    Full Text Available Direct Dark Matter searches are nowadays one of the most exciting research topics. Several experimental efforts are concentrated on the development, construction, and operation of detectors looking for the scattering of target nuclei with Weakly Interactive Massive Particles (WIMPs. The measurement of the direction of WIMP-induced nuclear recoils is a challenging strategy to extend dark matter searches beyond the neutrino floor and provide an unambiguous signature of the detection of Galactic dark matter. Current directional experiments are based on the use of gas TPC whose sensitivity is strongly limited by the small achievable detector mass. We present an innovative directional experiment based on the use of a solid target made by newly developed nuclear emulsions and read-out systems reaching a position resolution of the order of 10 nm.

  11. NEWSdm: Nuclear Emulsions for WIMP Search with directional measurement

    Di Crescenzo, A.

    2017-12-01

    Direct Dark Matter searches are nowadays one of the most exciting research topics. Several experimental efforts are concentrated on the development, construction, and operation of detectors looking for the scattering of target nuclei with Weakly Interactive Massive Particles (WIMPs). The measurement of the direction of WIMP-induced nuclear recoils is a challenging strategy to extend dark matter searches beyond the neutrino floor and provide an unambiguous signature of the detection of Galactic dark matter. Current directional experiments are based on the use of gas TPC whose sensitivity is strongly limited by the small achievable detector mass. We present an innovative directional experiment based on the use of a solid target made by newly developed nuclear emulsions and read-out systems reaching a position resolution of the order of 10 nm.

  12. Simulation of leakage current measurement on medical devices using helmholtz coil configuration with different current flow

    Sutanto, E.; Chandra, F.; Dinata, R.

    2017-05-01

    Leakage current measurement which can follow IEC standard for medical device is one of many challenges to be answered. The IEC 60601-1 has defined that the limit for a leakage current for Medical Device can be as low as 10 µA and as high as 500 µA, depending on which type of contact (applied part) connected to the patient. Most people are using ELCB (Earth-leakage circuit breaker) for safety purpose as this is the most common and available safety device in market. One type of ELCB devices is RCD (Residual Current Device) and this RCD type can measure the leakage current directly. This work will show the possibility on how Helmholtz Coil Configuration can be made to be like the RCD. The possibility is explored by comparing the magnetic field formula from each device, then it proceeds with a simulation using software EJS (Easy Java Simulation). The simulation will make sure the concept of magnetic field current cancellation follows the RCD concept. Finally, the possibility of increasing the measurement’s sensitivity is also analyzed. The sensitivity is needed to see the possibility on reaching the minimum leakage current limit defined by IEC, 0.01mA.

  13. Simulation of leakage current measurement on medical devices using helmholtz coil configuration with different current flow

    Sutanto, E; Chandra, F; Dinata, R

    2017-01-01

    Leakage current measurement which can follow IEC standard for medical device is one of many challenges to be answered. The IEC 60601-1 has defined that the limit for a leakage current for Medical Device can be as low as 10 µA and as high as 500 µA, depending on which type of contact (applied part) connected to the patient. Most people are using ELCB (Earth-leakage circuit breaker) for safety purpose as this is the most common and available safety device in market. One type of ELCB devices is RCD (Residual Current Device) and this RCD type can measure the leakage current directly. This work will show the possibility on how Helmholtz Coil Configuration can be made to be like the RCD. The possibility is explored by comparing the magnetic field formula from each device, then it proceeds with a simulation using software EJS (Easy Java Simulation). The simulation will make sure the concept of magnetic field current cancellation follows the RCD concept. Finally, the possibility of increasing the measurement’s sensitivity is also analyzed. The sensitivity is needed to see the possibility on reaching the minimum leakage current limit defined by IEC, 0.01mA. (paper)

  14. Leakage current measurements on pixelated CdZnTe detectors

    Dirks, B.P.F.; Blondel, C.; Daly, F.; Gevin, O.; Limousin, O.; Lugiez, F.

    2006-01-01

    In the field of the R and D of a new generation hard X-ray cameras for space applications we focus on the use of pixelated CdTe or CdZnTe semiconductor detectors. They are covered with 64 (0.9x0.9 mm 2 ) or 256 (0.5x0.5 mm 2 ) pixels, surrounded by a guard ring and operate in the energy ranging from several keV to 1 MeV, at temperatures between -20 and +20 o C. A critical parameter in the characterisation of these detectors is the leakage current per pixel under polarisation (∼50-500 V/mm). In operation mode each pixel will be read-out by an integrated spectroscopy channel of the multi-channel IDeF-X ASIC currently developed in our lab. The design and functionality of the ASIC depends directly on the direction and value of the current. A dedicated and highly insulating electronics circuit is designed to automatically measure the current in each individual pixel, which is in the order of tens of pico-amperes. Leakage current maps of different CdZnTe detectors of 2 and 6 mm thick and at various temperatures are presented and discussed. Defect density diagnostics have been performed by calculation of the activation energy of the material

  15. Oceanography of Wadge bank - current measurements over a tidal cycle off the south coast of India

    RamaRaju, V.S.; RameshBabu, V.; Anto, A.F.

    Direct current measurements made during the onset and termination of SW monsoon indicate wide fluctuations in space and time. The nearshore current decreases in magnitude from the onset to the termination of the monsoon. The resultant surface...

  16. A fiber-optic current sensor for lightning measurement applications

    Nguyen, Truong X.; Ely, Jay J.; Szatkowski, George N.

    2015-05-01

    An optical-fiber sensor based on Faraday Effect is developed for measuring total lightning electric current. It has many unique capabilities not possible with traditional current sensors. Designed for aircraft installation, the sensor is lightweight, non-conducting, structure-conforming, and is immune to electromagnetic interference, hysteresis and saturation. It can also be used on windmills, lightning towers, and can help validate lightning detection network measurements. Faraday Effect causes light polarization to rotate when the fiber is exposed to a magnetic field in the direction of light propagation. Thus, the magnetic field strength can be determined from the light polarization change. By forming closed fiber loops and applying Ampere's law, measuring the total light rotation yields the total current enclosed. The broadband, dual-detector, reflective polarimetric scheme allows measurement of both DC component and AC waveforms with about 60 dB dynamic range. Three sensor systems were built with different sensitivities from different laser wavelengths. Operating at 850nm, the first system uses twisted single-mode fiber and has a 150 A - 150 KA range. The second system operates at 1550nm, uses spun polarization maintaining fiber, and can measure 400 A - 400 KA. Both systems were validated with rocket-triggered lightning measurements and achieved excellent results when compared to a resistive shunt. The third system operates at 1310nm, uses spun polarization maintaining fiber, and can measure approximately 300 A - 300 KA. High current measurements up to 200 KA were demonstrated at a commercial lightning test facility. The system was recently installed on an aircraft and flown near icing weather conditions.

  17. A Fiber-Optic Current Sensor for Lightning Measurement Applications

    Nguyen, Truong X.; Ely, Jay J.; Szatkowski, George N.

    2015-01-01

    An optical-fiber sensor based on Faraday Effect is developed for measuring total lightning electric current. It has many unique capabilities not possible with traditional current sensors. Designed for aircraft installation, the sensor is lightweight, non-conducting, structure-conforming, and is immune to electromagnetic interference, hysteresis and saturation. It can also be used on windmills, lightning towers, and can help validate lightning detection network measurements. Faraday Effect causes light polarization to rotate when the fiber is exposed to a magnetic field in the direction of light propagation. Thus, the magnetic field strength can be determined from the light polarization change. By forming closed fiber loops and applying Ampere's law, measuring the total light rotation yields the total current enclosed. The broadband, dual-detector, reflective polarimetric scheme allows measurement of both DC component and AC waveforms with about 60 dB dynamic range. Three sensor systems were built with different sensitivities from different laser wavelengths. Operating at 850nm, the first system uses twisted single-mode fiber and has a 150 A - 150 KA range. The second system operates at 1550nm, uses spun polarization maintaining fiber, and can measure 400 A - 400 KA. Both systems were validated with rocket-triggered lightning measurements and achieved excellent results when compared to a resistive shunt. The third system operates at 1310nm, uses spun polarization maintaining fiber, and can measure approximately 300 A - 300 KA. High current measurements up to 200 KA were demonstrated at a commercial lightning test facility. The system was recently installed on an aircraft and flown near icing weather conditions.

  18. Optimization of focality and direction in dense electrode array transcranial direct current stimulation (tDCS)

    Guler, Seyhmus; Dannhauer, Moritz; Erem, Burak; Macleod, Rob; Tucker, Don; Turovets, Sergei; Luu, Phan; Erdogmus, Deniz; Brooks, Dana H.

    2016-06-01

    Objective. Transcranial direct current stimulation (tDCS) aims to alter brain function non-invasively via electrodes placed on the scalp. Conventional tDCS uses two relatively large patch electrodes to deliver electrical current to the brain region of interest (ROI). Recent studies have shown that using dense arrays containing up to 512 smaller electrodes may increase the precision of targeting ROIs. However, this creates a need for methods to determine effective and safe stimulus patterns as the number of degrees of freedom is much higher with such arrays. Several approaches to this problem have appeared in the literature. In this paper, we describe a new method for calculating optimal electrode stimulus patterns for targeted and directional modulation in dense array tDCS which differs in some important aspects with methods reported to date. Approach. We optimize stimulus pattern of dense arrays with fixed electrode placement to maximize the current density in a particular direction in the ROI. We impose a flexible set of safety constraints on the current power in the brain, individual electrode currents, and total injected current, to protect subject safety. The proposed optimization problem is convex and thus efficiently solved using existing optimization software to find unique and globally optimal electrode stimulus patterns. Main results. Solutions for four anatomical ROIs based on a realistic head model are shown as exemplary results. To illustrate the differences between our approach and previously introduced methods, we compare our method with two of the other leading methods in the literature. We also report on extensive simulations that show the effect of the values chosen for each proposed safety constraint bound on the optimized stimulus patterns. Significance. The proposed optimization approach employs volume based ROIs, easily adapts to different sets of safety constraints, and takes negligible time to compute. An in-depth comparison study gives

  19. Determining Confounding Sensitivities In Eddy Current Thin Film Measurements

    Gros, Ethan; Udpa, Lalita; Smith, James A.; Wachs, Katelyn

    2016-07-01

    Determining Confounding Sensitivities In Eddy Current Thin Film Measurements Ethan Gros, Lalita Udpa, Electrical Engineering, Michigan State University, East Lansing MI 48824 James A. Smith, Experiment Analysis, Idaho National Laboratory, Idaho Falls ID 83415 Eddy current (EC) techniques are widely used in industry to measure the thickness of non-conductive films on a metal substrate. This is done using a system whereby a coil carrying a high-frequency alternating current is used to create an alternating magnetic field at the surface of the instrument's probe. When the probe is brought near a conductive surface, the alternating magnetic field will induce ECs in the conductor. The substrate characteristics and the distance of the probe from the substrate (the coating thickness) affect the magnitude of the ECs. The induced currents load the probe coil affecting the terminal impedance of the coil. The measured probe impedance is related to the lift off between coil and conductor as well as conductivity of the test sample. For a known conductivity sample, the probe impedance can be converted into an equivalent film thickness value. The EC measurement can be confounded by a number of measurement parameters. It is the goal of this research to determine which physical properties of the measurement set-up and sample can adversely affect the thickness measurement. The eddy current testing is performed using a commercially available, hand held eddy current probe (ETA3.3H spring loaded eddy probe running at 8 MHz) that comes with a stand to hold the probe. The stand holds the probe and adjusts the probe on the z-axis to help position the probe in the correct area as well as make precise measurements. The signal from the probe is sent to a hand held readout, where the results are recorded directly in terms of liftoff or film thickness. Understanding the effect of certain factors on the measurements of film thickness, will help to evaluate how accurate the ETA3.3H spring

  20. Direct-current-like Phase Space Manipulation Using Chirped Alternating Current Fields

    Schmit, P.F.; Fisch, N.J.

    2010-01-01

    Waves in plasmas can accelerate particles that are resonant with the wave. A dc electric field also accelerates particles, but without a resonance discrimination, which makes the acceleration mechanism profoundly different. Whereas wave-particle acceleration mechanisms have been widely discussed in the literature, this work discusses the direct analogy between wave acceleration and dc field acceleration in a particular parameter regime explored in previous works. Apart from the academic interest of this correspondence, there may be practical advantages in using waves to mimic dc electric fields, for example, in driving plasma current with high efficiency.

  1. Wave directional spectrum from array measurements

    Fernandes, A.A; Sarma, Y; Menon, H.B.

    Using the method of Esteva (1976, 1977), whcih assumes that at the frequency band the waves approach from just a single "mean" wave direction, wave direction has been consistently, accurately and unambiguously evaluated as a function of frequency...

  2. Current and future directions of DNA in wildlife forensic science.

    Johnson, Rebecca N; Wilson-Wilde, Linzi; Linacre, Adrian

    2014-05-01

    Wildlife forensic science may not have attained the profile of human identification, yet the scale of criminal activity related to wildlife is extensive by any measure. Service delivery in the arena of wildlife forensic science is often ad hoc, unco-ordinated and unregulated, yet many of those currently dedicated to wildlife conservation and the protection of endangered species are striving to ensure that the highest standards are met. The genetic markers and software used to evaluate data in wildlife forensic science are more varied than those in human forensic identification and are rarely standardised between species. The time and resources required to characterise and validate each genetic maker is considerable and in some cases prohibitive. Further, issues are regularly encountered in the construction of allelic databases and allelic ladders; essential in human identification studies, but also applicable to wildlife criminal investigations. Accreditation and certification are essential in human identification and are currently being strived for in the forensic wildlife community. Examples are provided as to how best practice can be demonstrated in all areas of wildlife crime analysis and ensure that this field of forensic science gains and maintains the respect it deserves. This review is aimed at those conducting human identification to illustrate how research concepts in wildlife forensic science can be used in the criminal justice system, as well as describing the real importance of this type of forensic analysis. Crown Copyright © 2013. Published by Elsevier Ireland Ltd. All rights reserved.

  3. Direct current stabilization of scintillation counters used for uranium prospecting

    Fraser, H.J.

    1976-01-01

    A simple system for stabilizing a scintillation counter is described which uses a dc light source (a green light emitting diode) to illuminate the photo-cathode of the photomultiplier used to detect γ-induced light pulses from the scintillator. Basically, the photomultiplier anode current due to the light emitting diode light is held constant by an automatic control loop acting on the eht voltage to keep the gain of the photomultiplier tube constant. However, because the temperature coefficient of the scintillator does not in general match that of the light emitting diode, further compensation is required to achieve constant γ pulse gain. This is provided by adding to the control circuit a current derived from the light emitting diode voltage which is an excellent measure of temperature; the use of this technique results in gain constancy to within +-1% in the 10-50 0 C ambient temperature range. Noise and countrate limitations are discussed and it is concluded that the system is generally applicable to uranium prospecting equipment. (Auth.)

  4. The Philippine historical earthquakecatalog: its development, current stateand future directions

    B. C. Bautista

    2004-06-01

    Full Text Available This report will trace the development of the historical earthquake catalog of the Philippines, assess its present state and recommend future research directions. The current Philippine historical earthquake catalog is culled from various catalogs, both global and local, that were developed since the first Philippine catalog by Perrey was published in 1860. While early global catalogs gave simple mention of earthquakes in the Philippines, more focused earthquake catalogs about the Philippines gave more explicit descriptions of earthquake accounts and adopted descriptions by local historians. Over the years, various historians and seismologists continued to compile their catalogs whose contents depended on the author?s perspectives and purposes. These works varied from simple listings to others including detailed descriptions. It was only recently that an attempt made to parameterize the magnitudes and epicenters of Philippine historical earthquakes using magnitude-felt area relations was done. A more detailed catalog, however, is now underway that will show details of intensity distribution for each significant historical earthquake. By comparing the historical catalog with the recent catalog and assuming that the recent catalog is complete, we find that there are still a substantial amount of historical earthquakes that needs to be reviewed and located. Possible sources of new information are local libraries, museums and archives in the Philippines, Spain and other Southeast Asian countries to which the country was in contact with during historical times.

  5. Current DOE direction in low-level waste management

    Wilhite, E.L.; Dolenc, M.R.; Shupe, M.W.; Waldo, L.C.

    1989-01-01

    The U.S. Department of Energy (DOE) is implementing revised DOE Order 5820.2A Radioactive Waste Management. Chapter III of the revised order provides prescriptive requirements for managing low-level waste and is the subject of this paper. The revised order requires that all DOE low-level radioactive and mixed waste be systematically managed, using an approach that considers the combination of waste management practices used in waste generation reduction, segregation, treatment, packaging, storage, and disposal. The Order defines performance objectives for protecting groundwater, for protecting against intrusion, and for maintaining adequate operational practices. A performance assessment will be required to ensure that waste management operations comply with these performance objectives. DOE implementation of the revised Order includes work in the areas of leach testing, waste stabilization, waste certification, facility monitoring, and management of unique waste streams. This paper summarizes the status of this work and the current direction DOE is taking in managing low-level waste under DOE 5820.2A

  6. Grading of direct laryngoscopy. A survey of current practice.

    Cohen, A M; Fleming, B G; Wace, J R

    1994-06-01

    One hundred and twenty anaesthetists (30 of each grade), from three separate regions, were interviewed as to how they recorded the appearance of laryngeal structures at direct laryngoscopy and about their knowledge of the commonly used numerical grading system. About two-thirds of anaesthetists surveyed (69.2%) used the numerical grading system, but of these, over half could not identify a 'grade 2' laryngoscopic appearance correctly. Of anaesthetists who did not use the numerical method, over half could not correctly state the difference between a 'grade 2' and a 'grade 3' laryngoscopic appearance. Over 40% of anaesthetists stated incorrectly that the grading should be made on the initial view, even when laryngeal pressure had been needed. Junior anaesthetists were more likely to use the numerical method of recording. The results show that there is unacceptable uncertainty and inaccuracy in the use of the numerical grading system by users as well as non-users, which makes the current routine clinical use of the numerical grading system unsatisfactory.

  7. Molecular ultrasound imaging: current status and future directions

    Deshpande, N.; Needles, A.; Willmann, J.K.

    2010-01-01

    Targeted contrast-enhanced ultrasound (molecular ultrasound) is an emerging imaging strategy that combines ultrasound technology with novel molecularly-targeted ultrasound contrast agents for assessing biological processes at the molecular level. Molecular ultrasound contrast agents are nano- or micro-sized particles that are targeted to specific molecular markers by adding high-affinity binding ligands onto the surface of the particles. Following intravenous administration, these targeted ultrasound contrast agents accumulate at tissue sites overexpressing specific molecular markers, thereby enhancing the ultrasound imaging signal. High spatial and temporal resolution, real-time imaging, non-invasiveness, relatively low costs, lack of ionising irradiation and wide availability of ultrasound systems are advantages compared to other molecular imaging modalities. In this article we review current concepts and future directions of molecular ultrasound imaging, including different classes of molecular ultrasound contrast agents, ongoing technical developments of pre-clinical and clinical ultrasound systems, the potential of molecular ultrasound for imaging different diseases at the molecular level, and the translation of molecular ultrasound into the clinic.

  8. Current frontiers and future directions of telecoupling research

    Liu, J.

    2016-12-01

    The world has been increasingly interconnected over long distances though processes such as international trade, migration, telecommunication, and disease spread. However, previous studies often focused on socioeconomic or environmental issues of distant processes. While these studies have generated useful information for individual disciplines, integrating socioeconomic and environmental information is essential for holistic understanding of complex global challenges and unbiased decision making to address the challenges. To advance integrated research, the framework of telecoupling (socioeconomic and environmental interactions over distances) has been developed to explicitly address both socioeconomic and environmental issues simultaneously. Although the framework is relatively new, it has already been applied to tackle a variety of globally important issues, such as food security, water resources, energy sustainability, land use, international trade (e.g., food, forest products, energy, wildlife, industrial products), species invasion, investment, ecosystem services, conservation, information dissemination, and tourism. These applications have identified many important research gaps (e.g. spillover systems) and hidden linkages (e.g. feedbacks) among distant areas of the world with profound implications for sustainable development, ecosystem health, and human well-being. While working with telecoupling presents more challenges than focusing only on disciplinary issues, support from funding agencies has helped accelerate research on telecoupling and more efforts are being aimed at framework quantification and operationalization. The presenter will provide an overview of the current frontiers, discuss future research directions, and highlight emerging opportunities and challenges in telecoupling research and governance.

  9. Transcranial Direct Current Stimulation and behavioral models of smoking addiction

    Paige eFraser

    2012-08-01

    Full Text Available While few studies have applied transcranial direct current stimulation (tDCS to smoking addiction, existing work suggests that the intervention holds promise for altering the complex system by which environmental cues interact with cravings to drive behavior. Imaging and repetitive transcranial magnetic stimulation (rTMS studies suggest that increased dorsolateral prefrontal cortex (DLPFC activation and integrity may be associated with increased resistance to smoking cues. Anodal tDCS of the DLPFC, believed to boost activation, reduces cravings in response to these cues. The finding that noninvasive stimulation modifies cue induced cravings has profound implications for understanding the processes underlying addiction and relapse. TDCS can also be applied to probe mechanisms underlying and supporting nicotine addiction, as was done in a pharmacologic study that applied nicotine, tDCS, and TMS paired associative stimulation to find that stopping nicotine after chronic use induces a reduction in plasticity, causing difficulty in breaking free from association between cues and cravings. This mini-review will place studies that apply tDCS to smokers in the context of research involving the neural substrates of nicotine addiction.

  10. Compulsory Checking of Nuclear Power Engineering Materials by Direct and Eddy Current

    Larionov, V. V.; Lider, A. M.; Sednev, D. A.; Xu, Shupeng

    2016-08-01

    The testing technology of copper parts designed for dry storage of spent nuclear fuel with application of direct and eddy current has been developed. Measurements results of flaw quantity caused hydrogenation and oxidation processes are presented. Evolution of copper M 001 flaw structure during hydrogenation from gaseous medium is analyzed. It has been demonstrated that the dependence of copper p electrical resistance on number of flaws in its structure has dome shaped character and changes with eddy current frequency change. Number of flaws formed by hydrogen depends on direction (100) or (200) of the crystal structure of copper lattice.

  11. Dependence of critical current density on crystalline direction in thin YBCO films

    Paturi, P.; Peurla, M.; Raittila, J.

    2005-01-01

    The dependence of critical current density (J(c)) on the angle between the current direction and the (100) direction in the ab-plane of thin YBCO films deposited on (001)-SrTiO3 from natiocrystalline and microcrystalline targets is studied using magneto-optical microscopy. In the films made from...... the nanocrystalline target it is found that J(c) does not depend on the angle whereas J(c) decreases with increasing angle in the films made from the microcrystalline target. The films were characterized by detailed X-ray diffraction measurements. The findings are explained in terms of a network of planar defects...

  12. Clinical Research with Transcranial Direct Current Stimulation (tDCS): Challenges and Future Directions

    Brunoni, Andre Russowsky; Nitsche, Michael A.; Bolognini, Nadia; Bikson, Marom; Wagner, Tim; Merabet, Lotfi; Edwards, Dylan J.; Valero-Cabre, Antoni; Rotenberg, Alexander; Pascual-Leone, Alvaro; Ferrucci, Roberta; Priori, Alberto; Boggio, Paulo; Fregni, Felipe

    2011-01-01

    Background Transcranial direct current stimulation (tDCS) is a neuromodulatory technique that delivers low-intensity, direct current to cortical areas facilitating or inhibiting spontaneous neuronal activity. In the past ten years, tDCS physiological mechanisms of action have been intensively investigated giving support for the investigation of its applications in clinical neuropsychiatry and rehabilitation. However, new methodological, ethical, and regulatory issues emerge when translating the findings of preclinical and phase I studies into phase II and III clinical studies. The aim of this comprehensive review is to discuss the key challenges of this process and possible methods to address them. Methods We convened a workgroup of researchers in the field to review, discuss and provide updates and key challenges of neuromodulation use for clinical research. Main Findings/Discussion We reviewed several basic and clinical studies in the field and identified potential limitations, taking into account the particularities of the technique. We review and discuss the findings into four topics: (i) mechanisms of action of tDCS, parameters of use and computer-based human brain modeling investigating electric current fields and magnitude induced by tDCS; (ii) methodological aspects related to the clinical research of tDCS as divided according to study phase (i.e., preclinical, phase I, phase II and phase III studies); (iii) ethical and regulatory concerns; (iv) future directions regarding novel approaches, novel devices, and future studies involving tDCS. Finally, we propose some alternative methods to facilitate clinical research on tDCS. PMID:22037126

  13. Transcranial Direct Current Stimulation Does Not Improve Language Outcome in Subacute Poststroke Aphasia.

    Spielmann, Kerstin; van de Sandt-Koenderman, W Mieke E; Heijenbrok-Kal, Majanka H; Ribbers, Gerard M

    2018-04-01

    The aim of the present study is to investigate the effect of transcranial direct current stimulation on word-finding treatment outcome in subacute poststroke aphasia. In this multi-center, double-blind, randomized controlled trial with 6-month follow-up, we included 58 patients with subacute aphasia (transcranial direct current stimulation (1 mA, 20 minutes; experimental group) or sham transcranial direct current stimulation (control group) over the left inferior frontal gyrus. The primary outcome measure was the Boston Naming Test. Secondary outcome measures included naming performance for trained/untrained picture items and verbal communication. Both the experimental (n=26) and the control group (n=32) improved on the Boston Naming Test over the intervention period and 6-month follow-up; however, there were no significant differences between groups. Also for the secondary outcome measures, no significant differences were found. The results of the present study do not support an effect of transcranial direct current stimulation as an adjuvant treatment in subacute poststroke aphasia. URL: http://www.trialregister.nl/trialreg/admin/rctview.asp. Unique identifier: NTR4364. © 2018 American Heart Association, Inc.

  14. Circuit for current measures from ionization chambers

    Mello, F.L.V. de; Oliveira, A.H. de; Rezende, R.S.

    1992-01-01

    The design and the specifications of an ammeters of low cost for small current, IOE-14 Ampere, from ionization chambers or others transducers used in nuclear instrumentation are described. Special attention is given to the integrated electronic components, available in the brazilian market. (C.G.C.)

  15. Innovations in electrophoretic deposition: Alternating current and pulsed direct current methods

    Chávez-Valdez, Alejandra; Boccaccini, Aldo R.

    2012-01-01

    This review summarizes emerging developments in the field of alternating current (AC) and pulsed direct current (DC) electrophoretic deposition (EPD) in aqueous or organic media. Numerous applications of AC-EPD are discussed including two major groups of investigations: (i) AC-EPD to suppress water hydrolysis at high voltages in inorganic (ceramic) coatings and (ii) AC-EPD for deposition of biological entities. The deposition, purification and manipulation of carbon nanotubes and nanoparticles by AC-EPD to form specific arrays, for development of sensors and other electronic devices and the application of AC-EPD as method for separation of particles according to their shape or size are also presented. Other applications reviewed relate to the fabrication by AC-EPD of toxic gas sensors from oxides and superconducting layers. The main materials being examined by AC-EPD are inorganic, including carbon nanotubes, TiO 2 nanoparticles, Al 2 O 3 , Si, SnO 2 , ZnO and WO 3 and biological entities, e.g. bacteria cells. For pulsed EPD, the applications reviewed are divided in pulsed current and pulsed voltage EPD. Among the applications of pulsed EPD, the formation of thick films from aqueous suspensions without water decomposition, the fabrication of multilayer and composite materials and the size-selective deposition of ceramic nanoparticles are the most important investigated to date, based on the quality of the coatings and deposits obtained and their relevance for applications.

  16. Electrochemical synthesis of nanosized hydroxyapatite by pulsed direct current method

    Nur, Adrian; Rahmawati, Alifah; Ilmi, Noor Izzati; Affandi, Samsudin; Widjaja, Arief [Departement of Chemical Engineering, Faculty of Industrial Technology, Sepuluh Nopember Institute of Technology, Kampus ITS Sukolilo, Surabaya 60111 (Indonesia)

    2014-02-24

    Synthesis of nanosized of hydroxyapatite (HA) by electrochemical pulsed direct current (PDC) method has been studied. The aim of this work is to study the influence of various PDC parameters (pH initial, electrode distance, duty cycle, frequency, and amplitude) on particle surface area of HA powders. The electrochemical synthesis was prepared in solution Ca{sup 2+}/EDTA{sup 4−}/PO{sub 4}{sup 3+} at concentration 0.25/0.25/0.15 M for 24 h. The electrochemical cell was consisted of two carbon rectangular electrodes connected to a function generator to produce PDC. There were two treatments for particles after electrosynthesized, namely without aging and aged for 2 days at 40 °C. For both cases, the particles were filtered and washed by demineralized water to eliminate the impurities and unreacted reactants. Then, the particles were dried at 100 °C for 2 days. The dried particles were characterized by X-ray diffraction, surface area analyzer, scanning electron microscopy (SEM), Fourier transform infrared spectra and thermogravimetric and differential thermal analysis. HA particles can be produced when the initial pH > 6. The aging process has significant effect on the produced HA particles. SEM images of HA particles showed that the powders consisted of agglomerates composed of fine crystallites and have morphology plate-like and sphere. The surface area of HA particles is in the range of 25 – 91 m{sup 2}/g. The largest particle surface area of HA was produced at 4 cm electrode distance, 80% cycle duty, frequency 0.1 Hz, amplitude 9 V and with aging process.

  17. Cerebellar transcranial direct current stimulation improves adaptive postural control.

    Poortvliet, Peter; Hsieh, Billie; Cresswell, Andrew; Au, Jacky; Meinzer, Marcus

    2018-01-01

    Rehabilitation interventions contribute to recovery of impaired postural control, but it remains a priority to optimize their effectiveness. A promising strategy may involve transcranial direct current stimulation (tDCS) of brain areas involved in fine-tuning of motor adaptation. This study explored the effects of cerebellar tDCS (ctDCS) on postural recovery from disturbance by Achilles tendon vibration. Twenty-eight healthy volunteers participated in this sham-ctDCS controlled study. Standing blindfolded on a force platform, four trials were completed: 60 s quiet standing followed by 20 min active (anodal-tDCS, 1 mA, 20 min, N = 14) or sham-ctDCS (40 s, N = 14) tDCS; three quiet standing trials with 15 s of Achilles tendon vibration and 25 s of postural recovery. Postural steadiness was quantified as displacement, standard deviation and path derived from the center of pressure (COP). Baseline demographics and quiet standing postural steadiness, and backwards displacement during vibration were comparable between groups. However, active-tDCS significantly improved postural steadiness during vibration and reduced forward displacement and variability in COP derivatives during recovery. We demonstrate that ctDCS results in short-term improvement of postural adaptation in healthy individuals. Future studies need to investigate if multisession ctDCS combined with training or rehabilitation interventions can induce prolonged improvement of postural balance. Copyright © 2017 International Federation of Clinical Neurophysiology. Published by Elsevier B.V. All rights reserved.

  18. Transcranial direct current stimulation versus caffeine as a fatigue countermeasure.

    McIntire, Lindsey K; McKinley, R Andy; Nelson, Justin M; Goodyear, Chuck

    To assess the efficacy of using transcranial direct current stimulation (tDCS) to remediate the deleterious effects of fatigue induced by sleep deprivation and compare these results to caffeine, a commonly used fatigue countermeasure. Based on previous research, tDCS of the dorsolateral prefrontal cortex (DLPFC) can modulate attention and arousal. The authors hypothesize that tDCS can be an effective fatigue countermeasure. Five groups of ten participants each received either active tDCS and placebo gum at 1800, caffeine gum with sham tDCS at 1800, active tDCS and placebo gum at 0400, caffeine gum with sham tDCS at 0400, or sham tDCS with placebo gum at 1800 and 0400 during 36-h of sustained wakefulness. Participants completed a vigilance task, working memory task, psychomotor vigilance task (PVT), and a procedural game beginning at 1800 h and continued every two hours throughout the night until 1900 the next day. tDCS dosed at 1800 provided 6 h of improved attentional accuracy and reaction times compared to the control group. Caffeine did not produce an effect. Both tDCS groups also had an improved effect on mood. Participants receiving tDCS reported feeling more vigor, less fatigue, and less bored throughout the night compared to the control and caffeine groups. We believe tDCS could be a powerful fatigue countermeasure. The effects appear to be comparable or possibly more beneficial than caffeine because they are longer lasting and mood remains more positive. Copyright © 2017 Elsevier Inc. All rights reserved.

  19. Current Understanding and Future Directions for Vocal Fold Mechanobiology

    Li, Nicole Y.K.; Heris, Hossein K.; Mongeau, Luc

    2013-01-01

    The vocal folds, which are located in the larynx, are the main organ of voice production for human communication. The vocal folds are under continuous biomechanical stress similar to other mechanically active organs, such as the heart, lungs, tendons and muscles. During speech and singing, the vocal folds oscillate at frequencies ranging from 20 Hz to 3 kHz with amplitudes of a few millimeters. The biomechanical stress associated with accumulated phonation is believed to alter vocal fold cell activity and tissue structure in many ways. Excessive phonatory stress can damage tissue structure and induce a cell-mediated inflammatory response, resulting in a pathological vocal fold lesion. On the other hand, phonatory stress is one major factor in the maturation of the vocal folds into a specialized tri-layer structure. One specific form of vocal fold oscillation, which involves low impact and large amplitude excursion, is prescribed therapeutically for patients with mild vocal fold injuries. Although biomechanical forces affect vocal fold physiology and pathology, there is little understanding of how mechanical forces regulate these processes at the cellular and molecular level. Research into vocal fold mechanobiology has burgeoned over the past several years. Vocal fold bioreactors are being developed in several laboratories to provide a biomimic environment that allows the systematic manipulation of physical and biological factors on the cells of interest in vitro. Computer models have been used to simulate the integrated response of cells and proteins as a function of phonation stress. The purpose of this paper is to review current research on the mechanobiology of the vocal folds as it relates to growth, pathogenesis and treatment as well as to propose specific research directions that will advance our understanding of this subject. PMID:24812638

  20. Randomized trial of transcranial direct current stimulation for poststroke dysphagia.

    Suntrup-Krueger, Sonja; Ringmaier, Corinna; Muhle, Paul; Wollbrink, Andreas; Kemmling, Andre; Hanning, Uta; Claus, Inga; Warnecke, Tobias; Teismann, Inga; Pantev, Christo; Dziewas, Rainer

    2018-02-01

    We evaluated whether transcranial direct current stimulation (tDCS) is able to enhance dysphagia rehabilitation following stroke. Besides relating clinical effects with neuroplastic changes in cortical swallowing processing, we aimed to identify factors influencing treatment success. In this double-blind, randomized study, 60 acute dysphagic stroke patients received contralesional anodal (1mA, 20 minutes) or sham tDCS on 4 consecutive days. Swallowing function was thoroughly assessed before and after the intervention using the validated Fiberoptic Endoscopic Dysphagia Severity Scale (FEDSS) and clinical assessment. In 10 patients, swallowing-related brain activation was recorded applying magnetoencephalography before and after the intervention. Voxel-based statistical lesion pattern analysis was also performed. Study groups did not differ according to demographic data, stroke characteristics, or baseline dysphagia severity. Patients treated with tDCS showed greater improvement in FEDSS than the sham group (1.3 vs 0.4 points, mean difference = 0.9, 95% confidence interval [CI] = 0.4-1.4, p < 0.0005). Functional recovery was accompanied by a significant increase of activation (p < 0.05) in the contralesional swallowing network after real but not sham tDCS. Regarding predictors of treatment success, for every hour earlier that treatment was initiated, there was greater improvement on the FEDSS (adjusted odds ratio = 0.99, 95% CI = 0.98-1.00, p < 0.05) in multivariate analysis. Stroke location in the right insula and operculum was indicative of worse response to tDCS (p < 0.05). Application of tDCS over the contralesional swallowing motor cortex supports swallowing network reorganization, thereby leading to faster rehabilitation of acute poststroke dysphagia. Early treatment initiation seems beneficial. tDCS may be less effective in right-hemispheric insulo-opercular stroke. Ann Neurol 2018;83:328-340. © 2018 American Neurological

  1. High-quality cardiopulmonary resuscitation: current and future directions.

    Abella, Benjamin S

    2016-06-01

    Cardiopulmonary resuscitation (CPR) represents the cornerstone of cardiac arrest resuscitation care. Prompt delivery of high-quality CPR can dramatically improve survival outcomes; however, the definitions of optimal CPR have evolved over several decades. The present review will discuss the metrics of CPR delivery, and the evidence supporting the importance of CPR quality to improve clinical outcomes. The introduction of new technologies to quantify metrics of CPR delivery has yielded important insights into CPR quality. Investigations using CPR recording devices have allowed the assessment of specific CPR performance parameters and their relative importance regarding return of spontaneous circulation and survival to hospital discharge. Additional work has suggested new opportunities to measure physiologic markers during CPR and potentially tailor CPR delivery to patient requirements. Through recent laboratory and clinical investigations, a more evidence-based definition of high-quality CPR continues to emerge. Exciting opportunities now exist to study quantitative metrics of CPR and potentially guide resuscitation care in a goal-directed fashion. Concepts of high-quality CPR have also informed new approaches to training and quality improvement efforts for cardiac arrest care.

  2. Capnography during cardiopulmonary resuscitation: Current evidence and future directions

    Bhavani Shankar Kodali

    2014-01-01

    Full Text Available Capnography continues to be an important tool in measuring expired carbon dioxide (CO 2 . Most recent Advanced Cardiac Life Support (ACLS guidelines now recommend using capnography to ascertain the effectiveness of chest compressions and duration of cardiopulmonary resuscitation (CPR. Based on an extensive review of available published literature, we selected all available peer-reviewed research investigations and case reports. Available evidence suggests that there is significant correlation between partial pressure of end-tidal CO 2 (PETCO 2 and cardiac output that can indicate the return of spontaneous circulation (ROSC. Additional evidence favoring the use of capnography during CPR includes definitive proof of correct placement of the endotracheal tube and possible prediction of patient survival following cardiac arrest, although the latter will require further investigations. There is emerging evidence that PETCO 2 values can guide the initiation of extracorporeal life support (ECLS in refractory cardiac arrest (RCA. There is also increasing recognition of the value of capnography in intensive care settings in intubated patients. Future directions include determining the outcomes based on capnography waveforms PETCO 2 values and determining a reasonable duration of CPR. In the future, given increasing use of capnography during CPR large databases can be analyzed to predict outcomes.

  3. Wave measurement in severe ocean currents

    Diwan, S.G.; Suryavanshi, A.K.; Nayak, B.U.

    The measurement of ocean waves has been of particular interest, as wave data and understanding of wave phenomena are essential to ocean engineering, coastal engineering and to many marine operations. The National Institute of Oceanography, Goa...

  4. Current Status and Future Directions of Targeted Peptide Radionuclide Therapy

    Valkema, R.

    2009-01-01

    yr, hypertension and diabetes. Especially patients with a combination of more than two of the above mentioned risk factors may be prone to renal toxicity with PRRT. Bone marrow toxicity can be direct toxicity (grade 3-4 HGB, WBC, PLT, mostly reversible) or late stochastic effects (development of myelodysplasia and/or leukemia). Risk factors are previous chemotherapy, impaired renal function (creatinine clearance < 60 mL/min) and possibly age. With the current schedule of 4 cycles of 7.4 GBq Lu-DOTATATE each at 8-week intervals, and careful monitoring of relevant parameters, severe side effects occur only in about 1% of patients. For Y-DOTATOC and possibly Y-DOTATATE (NB: no dosimetry studies known) a cumulative activity of 13.3 GBq (360 mCi) fractionated in at least 3 to 4 cycles at 8-week intervals seems a safe schedule. Future developments: an FDA and EMEA approval of Y-DOTATOC and Lu-DOTATATE for PRRT is highly needed to establish this therapy modality. To achieve approval controlled clinical studies are required. The therapeutic window for sst-targeted PRRT can be widened to improve efficacy and/or decrease toxicity. Currently the addition of capacetabine as radiosensitizer to Lu- DOTATATE is investigated in a controlled trial. Patients who relapse after previous response to PRRT receive 2 additional cycles of Lu-DOTATATE. In patients with a single inoperable tumor, PRRT can be applied to shrink the tumor and to offer the patient surgery with curative intent afterwards. Animal experiments have shown that Lu-DOTATATE may prevent that liver tumors will develop after infusion of tumor cells in the portal vein; thus, Lu-DOTATATE may have a role in neo-adjuvant therapy

  5. Direct estimation of diffuse gaseous emissions from coal fires: current methods and future directions

    Engle, Mark A.; Olea, Ricardo A.; O'Keefe, Jennifer M. K.; Hower, James C.; Geboy, Nicholas J.

    2013-01-01

    Coal fires occur in nature spontaneously, contribute to increases in greenhouse gases, and emit atmospheric toxicants. Increasing interest in quantifying coal fire emissions has resulted in the adaptation and development of specialized approaches and adoption of numerical modeling techniques. Overview of these methods for direct estimation of diffuse gas emissions from coal fires is presented in this paper. Here we take advantage of stochastic Gaussian simulation to interpolate CO2 fluxes measured using a dynamic closed chamber at the Ruth Mullins coal fire in Perry County, Kentucky. This approach allows for preparing a map of diffuse gas emissions, one of the two primary ways that gases emanate from coal fires, and establishing the reliability of the study both locally and for the entire fire. Future research directions include continuous and automated sampling to improve quantification of gaseous coal fire emissions.

  6. Current status of direct dark matter detection experiments

    Liu, Jianglai; Chen, Xun; Ji, Xiangdong

    2017-03-01

    Much like ordinary matter, dark matter might consist of elementary particles, and weakly interacting massive particles are one of the prime suspects. During the past decade, the sensitivity of experiments trying to directly detect them has improved by three to four orders of magnitude, but solid evidence for their existence is yet to come. We overview the recent progress in direct dark matter detection experiments and discuss future directions.

  7. Digital DC beam current measurement on SSRF storage ring

    Xiong Liang; Yin Chongxian; Liu Ming; Chen Jianfeng

    2011-01-01

    Both DC current transformer (DCCT) and integrating current transformer (ICT) can be used in DC beam current measurement. The ICT has strong capability of resisting electromagnetic interference, but its measurement accuracy cannot satisfy the DC beam current measurement requirement when using traditional high speed A/D. With high resolution A/D and equivalent sampling system, DC beam current measuring system based on ICT can reach high accuracy compared with DCCT system. In this paper, the ICT-based DC beam current measurement, equivalent sampling method and testing results at Shanghai Synchrotron Radiation Facility(SSRF) is described. (authors)

  8. Electronegative Gas Thruster - Direct Thrust Measurement

    National Aeronautics and Space Administration — This effort is an international collaboration and academic partnership to mature an innovative electric propulsion (EP) thruster concept to TRL 3 through direct...

  9. Current measurement method for characterization of fast switching power semiconductors with Silicon Steel Current Transformer

    Li, Helong; Beczkowski, Szymon; Munk-Nielsen, Stig

    2015-01-01

    This paper proposes a novel current measurement method with Silicon Steel Current Transformer (SSCT) for the characterization of fast switching power semiconductors. First, the existing current sensors for characterization of fast switching power semiconductors are experimentally evaluated...

  10. A Comparison of Alternating Current and Direct Current Electrospray Ionization for Mass Spectrometry

    Sarver, Scott A.; Chetwani, Nishant; Dovichi, Norman J.; Go, David B.; Gartner, Carlos A.

    2014-04-01

    A series of studies comparing the performance of alternating current electrospray ionization (AC ESI) mass spectrometry (MS) and direct current electrospray ionization (DC ESI) MS have been conducted, exploring the absolute signal intensity and signal-to-background ratios produced by both methods using caffeine and a model peptide as targets. Because the high-voltage AC signal was more susceptible to generating gas discharges, the operating voltage range of AC ESI was significantly smaller than that for DC ESI, such that the absolute signal intensities produced by DC ESI at peak voltages were one to two orders of magnitude greater than those for AC ESI. Using an electronegative nebulizing gas, sulfur hexafluoride (SF6), instead of nitrogen (N2) increased the operating range of AC ESI by ~50 %, but did not appreciably improve signal intensities. While DC ESI generated far greater signal intensities, both ionization methods produced comparable signal-to-background noise, with AC ESI spectra appearing qualitatively cleaner. A quantitative calibration analysis was performed for two analytes, caffeine and the peptide MRFA. AC ESI utilizing SF6 outperforms all other techniques for the detection of MRFA, producing chromatographic limits of detection nearly one order of magnitude lower than that of DC ESI utilizing N2, and one-half that of DC ESI utilizing SF6. However, DC ESI outperforms AC ESI for the analysis of caffeine, indicating that improvements in spectral quality may benefit certain compounds or classes of compounds, on an individual basis.

  11. Apparatuses and method for converting electromagnetic radiation to direct current

    Kotter, Dale K; Novack, Steven D

    2014-09-30

    An energy conversion device may include a first antenna and a second antenna configured to generate an AC current responsive to incident radiation, at least one stripline, and a rectifier coupled with the at least one stripline along a length of the at least one stripline. An energy conversion device may also include an array of nanoantennas configured to generate an AC current in response to receiving incident radiation. Each nanoantenna of the array includes a pair of resonant elements, and a shared rectifier operably coupled to the pair of resonant elements, the shared rectifier configured to convert the AC current to a DC current. The energy conversion device may further include a bus structure operably coupled with the array of nanoantennas and configured to receive the DC current from the array of nanoantennas and transmit the DC current away from the array of nanoantennas.

  12. Effect of alternating and direct currents on Pseudomonas ...

    ONOS

    2010-09-20

    Sep 20, 2010 ... Based on the effect of natural selection, these bacteria become resistant to ..... Effect of electrical stimulation on chronic leg ulcer size and appearance. Phys. ... stimulation directly induces pre-angiogenic responses in vascular.

  13. U.S. Direct Investment Abroad: Trends and Current Issues

    Jackson, James K

    2007-01-01

    .... foreign direct investment is concentrated in high income developed countries. Even more striking is the fact that the share of investment going to developing countries has fallen in recent years...

  14. U.S. Direct Investment Abroad: Trends and Current Issues

    Jackson, James K

    2005-01-01

    .... foreign direct investment is concentrated in high income developed countries. Even more striking is the fact that the share of investment going to developing countries has fallen in recent years...

  15. U.S. Direct Investment Abroad: Trends and Current Issues

    Jackson, James K

    2006-01-01

    .... foreign direct investment is concentrated in high income developed countries. Even more striking is the fact that the share of investment going to developing countries has fallen in recent years...

  16. U.S. Direct Investment Abroad: Trends and Current Issues

    Jackson, James K

    2008-01-01

    .... foreign direct investment is concentrated in high-income developed countries. Even more striking is the fact that the share of investment going to developing countries has fallen in recent years...

  17. Social anxiety disorder and stuttering: current status and future directions.

    Iverach, Lisa; Rapee, Ronald M

    2014-06-01

    Anxiety is one of the most widely observed and extensively studied psychological concomitants of stuttering. Research conducted prior to the turn of the century produced evidence of heightened anxiety in people who stutter, yet findings were inconsistent and ambiguous. Failure to detect a clear and systematic relationship between anxiety and stuttering was attributed to methodological flaws, including use of small sample sizes and unidimensional measures of anxiety. More recent research, however, has generated far less equivocal findings when using social anxiety questionnaires and psychiatric diagnostic assessments in larger samples of people who stutter. In particular, a growing body of research has demonstrated an alarmingly high rate of social anxiety disorder among adults who stutter. Social anxiety disorder is a prevalent and chronic anxiety disorder characterised by significant fear of humiliation, embarrassment, and negative evaluation in social or performance-based situations. In light of the debilitating nature of social anxiety disorder, and the impact of stuttering on quality of life and personal functioning, collaboration between speech pathologists and psychologists is required to develop and implement comprehensive assessment and treatment programmes for social anxiety among people who stutter. This comprehensive approach has the potential to improve quality of life and engagement in everyday activities for people who stutter. Determining the prevalence of social anxiety disorder among children and adolescents who stutter is a critical line of future research. Further studies are also required to confirm the efficacy of Cognitive Behaviour Therapy in treating social anxiety disorder in stuttering. The reader will be able to: (a) describe the nature and course of social anxiety disorder; (b) outline previous research regarding anxiety and stuttering, including features of social anxiety disorder; (c) summarise research findings regarding the

  18. Eddy Current Flow Measurements in the FFTF

    Nielsen, Deborah L. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Polzin, David L. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Omberg, Ronald P. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Makenas, Bruce J. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

    2017-02-02

    The Fast Flux Test Facility (FFTF) is the most recent liquid metal reactor (LMR) to be designed, constructed, and operated by the U.S. Department of Energy (DOE). The 400-MWt sodium-cooled, fast-neutron flux reactor plant was designed for irradiation testing of nuclear reactor fuels and materials for liquid metal fast breeder reactors. Following shut down of the Clinch River Breeder Reactor Plant (CRBRP) project in 1983, FFTF continued to play a key role in providing a test bed for demonstrating performance of advanced fuel designs and demonstrating operation, maintenance, and safety of advanced liquid metal reactors. The FFTF Program provides valuable information for potential follow-on reactor projects in the areas of plant system and component design, component fabrication, fuel design and performance, prototype testing, site construction, and reactor control and operations. This report provides HEDL-TC-1344, “ECFM Flow Measurements in the FFTF Using Phase-Sensitive Detectors”, March 1979.

  19. Design and Construction of Variable Direct Current Speed Drive ...

    controlled rectifiers from the viewpoint of simplicity and cost effectiveness to act as power converter and controller. Design and construction of constituent circuits such as acceleration/deceleration, speed and current amplifier and the trigger ...

  20. Microparticle impact sensor measures energy directly

    Alexander, W. M.; Berg, O. E.

    1965-01-01

    Construction of a capacitor sensor consisting of a dielectric layer between two conductive surface layers and connected across a potential source through a sensing resistor permits measurement of energy of impinging particles without degradation of sensitivity. A measurable response is produced without penetration of the dielectric layer.

  1. Onsite-effects of dual-hemisphere versus conventional single-hemisphere transcranial direct current stimulation

    Kwon, Yong Hyun; Jang, Sung Ho

    2012-01-01

    We performed functional MRI examinations in six right-handed healthy subjects. During functional MRI scanning, transcranial direct current stimulation was delivered with the anode over the right primary sensorimotor cortex and the cathode over the left primary sensorimotor cortex using dual-hemispheric transcranial direct current stimulation. This was compared to a cathode over the left supraorbital area using conventional single-hemispheric transcranial direct current stimulation. Voxel counts and blood oxygenation level-dependent signal intensities in the right primary sensorimotor cortex regions were estimated and compared between the two transcranial direct current stimulation conditions. Our results showed that dual-hemispheric transcranial direct current stimulation induced greater cortical activities than single-hemispheric transcranial direct current stimulation. These findings suggest that dual-hemispheric transcranial direct current stimulation may provide more effective cortical stimulation than single-hemispheric transcranial direct current stimulation. PMID:25624815

  2. Functional Behavior Assessment in Schools: Current Status and Future Directions

    Anderson, Cynthia M.; Rodriguez, Billie Jo; Campbell, Amy

    2015-01-01

    Functional behavior assessment is becoming a commonly used practice in school settings. Accompanying this growth has been an increase in research on functional behavior assessment. We reviewed the extant literature on documenting indirect and direct methods of functional behavior assessment in school settings. To discern best practice guidelines…

  3. Modeling of Pulsed Direct-Current Glow Discharge

    Du Mu; Zheng Yaru; Fan Yujia; Zhang Nan; Liu Chengsen; Wang Dezhen

    2010-01-01

    A self-consistent model was adopted to study the time evolution of low-voltage pulsed DC glow discharge. The distributions of electric field, ion density and electron density in nitrogen were investigated in our simulation, and the temporal shape of the discharge current was also obtained. Our results show that the dynamic behaviors of the discharge depends strongly on the applied pulse voltage, and the use of higher pulse voltages results in a significantly increase of discharge current and a decrease of discharge delay time. The current-voltage characteristic calculated by adjusting secondary electron emission coefficient for different applied pulse voltage under the gas pressure of 1 Torr is found in a reasonable agreement with the experimental results.

  4. Measuring directional urban spatial interaction in China: A migration perspective.

    Li, Fangzhou; Feng, Zhiming; Li, Peng; You, Zhen

    2017-01-01

    The study of urban spatial interaction is closely linked to that of economic geography, urban planning, regional development, and so on. Currently, this topic is generating a great deal of interest among researchers who are striving to find accurate ways to measure urban spatial interaction. Classical spatial interaction models lack theoretical guidance and require complicated parameter-adjusting processes. The radiation model, however, as proposed by Simini et al. with rigorous formula derivation, can simulate directional urban spatial interaction. We applied the radiation model in China to simulate the directional migration number among 337 nationwide research units, comprising 4 municipalities and 333 prefecture-level cities. We then analyzed the overall situation in Chinese cities, the interaction intensity hierarchy, and the prime urban agglomerations from the perspective of migration. This was done to ascertain China's urban spatial interaction and regional development from 2000 to 2010 to reveal ground realities.

  5. On-Line Monitoring of Environment-Assisted Cracking in Nuclear Piping Using Array Probe Direct Current Potential Drop

    Kim, Y.; Choi, S.; Yoon, J. Y.; Nam, W. C.; Hwang, I. S.; Bromberg, Leslie; Stahle, Peter W; Ballinger, Ronald G

    2015-01-01

    A direct current potential drop method utilizing array probes with measurement ends maintaining an equalized potential designated as equi-potential switching array probe direct current potential drop (ESAP-DCPD) technique has been developed earlier at Seoul National University. This paper validates ESAP-DCPD technique by showing consistency among experimental measurements, analytical solution and numerical predictions using finite element analysis (FEA) of electric field changes with crack gr...

  6. Optical sensors for the measurement of electric current and voltage

    Rutgers, W R; Hulshof, H J.M.; Laurensse, I J; van der Wey, A H

    1987-01-01

    Optical sensors for the measurement of electrical current and voltage were developed for application in electric power systems. The current sensor, based on the Faraday effect in a monomode glass fiber, and the voltage sensor, based on the transverse Pockels effect in a crystal, are demonstrated in wide-band (10 MHz) interference-free measurements of pulsed currents and impulse voltages.

  7. BEAM-BASED MEASUREMENTS OF PERSISTENT CURRENT DECAY IN RHIC

    FISCHER, W.; JAIN, A.; TEPIKIAN, S.

    2001-01-01

    The two RHIC rings are equipped with superconducting dipole magnets. At injection, induced persistent currents in these magnets lead to a sextupole component. As the persistent currents decay with time, the horizontal and vertical chromaticities change. From magnet measurements of persistent current decays, chromaticity changes in the machine are estimated and compared with chromaticity measurements

  8. RPA Assessment of Outdoor Recreation: Past, Current, and Future Directions

    John C. Bergstrom; H. Ken Cordell

    1994-01-01

    In this paper, the outdoor recreation sections of the Renewable Resource Planning Act (RPA) Assessments conducted to date are reviewed. Current policy and mangement applications of the outsdoor recreation results published in 1989 Assessment are discussed also. The paper concludes with suggestions for the assemssment of outdoor recreation in future RPA Assessements...

  9. Business Education at Catholic Universities: Current Status and Future Directions

    Porth, Stephen J.; McCall, John J.; DiAngelo, Joseph A.

    2009-01-01

    Is business education at Catholic colleges and universities different than business education at secular institutions? This study assesses the current state of business education at Catholic colleges and universities based on a national survey of business school deans and faculty members and an audit of business unit web sites. Results suggest…

  10. Current status and new directions in conceptual aircraft design

    Kidwell, George H., Jr.

    1990-01-01

    The following topics are discussed: systems analysis branch questions; systems analysis; historical perspective; background technology; conceptual design/evaluation program organization; system integration/vehicle closure; conceptual design synthesis programs; numerical optimization/mathematical programming; and current R&D interests. The discussion is presented in viewgraph format.

  11. Chemical Reaction Engineering: Current Status and Future Directions.

    Dudukovic, M. P.

    1987-01-01

    Describes Chemical Reaction Engineering (CRE) as the discipline that quantifies the interplay of transport phenomena and kinetics in relating reactor performance to operating conditions and input variables. Addresses the current status of CRE in both academic and industrial settings and outlines future trends. (TW)

  12. Corporate Blended Learning in Portugal: Current Status and Future Directions

    Marcal, Julia; Caetano, Antonio

    2010-01-01

    The aim of this study is to characterize the current status of blended learning in Portugal, given that b-learning has grown exponentially in the Portuguese market over recent years. 38 organizations (representing 68% of all institutions certified to provide distance training by the Government Labour Office--DGERT-) participated in this study. The…

  13. Directed Motivational Currents: Using Vision to Create Effective Motivational Pathways

    Muir, Christine; Dörnyei, Zoltán

    2013-01-01

    Vision, that is, the mental representation of the sensory experience of a future goal state (involving imagination and imagery), is currently at the forefront of motivational innovation, and in recent years it has been seen increasingly more often in the motivational tool kit of practicing language teachers. Theories such as Dörnyei's L2…

  14. Effects of Transcranial Direct Current Stimulation on Expression of Immediate Early Genes (IEG’s)

    2015-12-01

    TRANSCRANIAL DIRECT CURRENT STIMULATION OF EXPRESSION OF IMMEDIATE EARLY GENES (IEG’S) Jessica...AND SUBTITLE Effects of Transcranial Direct Current Stimulation on Expression of Immediate Early Genes (IEG’s) 5a. CONTRACT NUMBER In-House 5b...community in better understanding what is occurring biologically during tDCS. 15. SUBJECT TERMS Transcranial direct current stimulation

  15. Visualizing Transcranial Direct Current Stimulation (tDCS) in vivo using Magnetic Resonance Imaging

    Jog, Mayank Anant

    Transcranial Direct Current Stimulation (tDCS) is a low-cost, non-invasive neuromodulation technique that has been shown to treat clinical symptoms as well as improve cognition. However, no techniques exist at the time of research to visualize tDCS currents in vivo. This dissertation presents the theoretical framework and experimental implementations of a novel MRI technique that enables non-invasive visualization of the tDCS electric current using magnetic field mapping. The first chapter establishes the feasibility of measuring magnetic fields induced by tDCS currents. The following chapter discusses the state of the art implementation that can measure magnetic field changes in individual subjects undergoing concurrent tDCS/MRI. The final chapter discusses how the developed technique was integrated with BOLD fMRI-an established MRI technique for measuring brain function. By enabling a concurrent measurement of the tDCS current induced magnetic field as well as the brain's hemodynamic response to tDCS, our technique opens a new avenue to investigate tDCS mechanisms and improve targeting.

  16. Implementing Measures of the Ecodesign Directive

    Andersen, Rikke Dorothea; Remmen, Arne

    2011-01-01

    on energy efficiency, power consumption, water consumption, information requirements and in some cases quality and performance issues. All IM only take the use phase of the products life time into consideration. The ambition level of the IM is analysed through a detailed case study of the IM for televisions....... It is argued that the IM have not succeeded in setting up sufficient ecodesign requirements, as only one life cycle phase and mainly one environmental impact category is addressed. The result of an analysis of televisions (TVs) on the market shows that new technologies have been developed that reduce power...... consumption significantly, and these technologies have been assessed not being mature enough to be included in the IM and the preparatory studies. Hence, it is concluded in this article that the process around the Ecodesign Directive has been too slow to be considered a driver for increasing material...

  17. Computers in nuclear medicine - current trends and future directions

    Anon.

    1994-01-01

    Previously, a decision to purchase computing equipment for nuclear medicine usually required evaluation of the 'local' needs. With the advent of Pacs and state of the art computer techniques for image acquisition and manipulation, purchase and subsequent application is to become much more complex. Some of the current trends and future possibilities which may influence the choice and operation of computers within and outside the nuclear medicine environment is discussed. (author)

  18. Directed Motivational Currents: Using vision to create effective motivational pathways

    Christine Muir; Zoltán Dörnyei

    2013-01-01

    Vision, that is, the mental representation of the sensory experience of a future goal state (involving imagination and imagery), is currently at the forefront of motivational innovation, and in recent years it has been seen increasingly more often in the motivational tool kit of practicing language teachers. Theories such as Dörnyei’s L2 motivational self system have explored the power that creating effective visions can harness (see, e.g., Dörnyei & Kubanyiova, 2014) and when viewed in conju...

  19. Current indirect fitness and future direct fitness are not incompatible.

    Brahma, Anindita; Mandal, Souvik; Gadagkar, Raghavendra

    2018-02-01

    In primitively eusocial insects, many individuals function as workers despite being capable of independent reproduction. Such altruistic behaviour is usually explained by the argument that workers gain indirect fitness by helping close genetic relatives. The focus on indirect fitness has left open the question of whether workers are also capable of getting direct fitness in the future in spite of working towards indirect fitness in the present. To investigate this question, we recorded behavioural profiles of all wasps on six naturally occurring nests of Ropalidia marginata , and then isolated all wasps in individual plastic boxes, giving them an opportunity to initiate nests and lay eggs. We found that 41% of the wasps successfully did so. Compared to those that failed to initiate nests, those that did were significantly younger, had significantly higher frequency of self-feeding behaviour on their parent nests but were not different in the levels of work performed in the parent nests. Thus ageing and poor feeding, rather than working for their colonies, constrain individuals for future independent reproduction. Hence, future direct fitness and present work towards gaining indirect fitness are not incompatible, making it easier for worker behaviour to be selected by kin selection or multilevel selection. © 2018 The Author(s).

  20. Eddy current imaging. Simplifying the direct problem. Analysis of a 2D case with formulations

    Spineanu, A.; Zorgati, R.

    1995-01-01

    Eddy current non-destructive testing is used by EDF to detect faults affecting conductive objects such as steam generator tubes. A new technique, known as eddy current imaging, is being developed to facilitate diagnosis in this context. The first stage in this work, discussed in the present paper, consists in solving the direct problem. This entails determining the measurable quantities, on the basis of a thorough knowledge of the material considered. This was done by formulating the direct problem in terms of eddy currents in general 3D geometry context, applying distribution theory and Maxwell equations. Since no direct problem code was available we resorted to simplified situations. Taking care not to interfere with previous developments or those to be attempted in an inversion context, we studied the case of a flaw affecting a 2D structure, illuminated by a plane wave type probe. For this configuration, we studied the exact model and compared results with those of a linearized simplified model. This study emphasizes the ill-posed situation of the eddy current inverse problem related with the severe electromagnetic field attenuation. This means that regularization of the inverse problem, although absolutely necessary, will not be sufficient. Owing to the simplicity of the models available and implemented during the inversion process, processing real data would not yet be possible. We must first focus all our efforts on the direct 3 D problem, in conformity with the requirements of the inverse procedure ad describing a realistic eddy current NDT situation. At the same time, consideration should be given to the design of a specific probe customized for eddy current imaging. (authors). 9 refs., 5 figs., 3 appends

  1. The effect of current flow direction on motor hot spot allocation by transcranial magnetic stimulation.

    Stephani, Caspar; Paulus, Walter; Sommer, Martin

    2016-01-01

    The objective of this study was to investigate the significance of pulse configurations and current direction for corticospinal activation using transcranial magnetic stimulation (TMS). In 11 healthy subjects (8 female), a motor map for the motor evoked potentials (MEPs) recorded from the first dorsal interosseus (FDI), abductor digiti minimi (ADM), extensor carpi radialis, and biceps brachii (BB) muscles of the dominant side was established. Starting from a manually determined hot spot of the FDI representation, we measured MEPs at equal oriented points on an hexagonal grid, with 7 MEPs recorded at each point, using the following pulse configurations: posteriorly directed monophasic (Mo-P), anteriorly directed monophasic (Mo-A), biphasic with the more relevant second cycle oriented posteriorly (Bi-P) as well as a reversed biphasic condition (Bi-A). For each pulse configuration, a hot spot was determined and a center of gravity (CoG) was calculated. We found that the factor current direction had an effect on location of the CoG-adjusted hot spot in the cranio-caudal axis but not in the latero-medial direction with anteriorly directed pulses locating the CoG more anteriorly and vice versa. In addition, the CoG for the FDI was more laterally than the cortical representations for the abductor digiti minimi (ADM) and extensor carpi radialis (ECR) which were registered as well. The results indicate that direction of the current pulse should be taken into account for determination of the motor representation of a muscle by TMS. © 2015 The Authors. Physiological Reports published by Wiley Periodicals, Inc. on behalf of the American Physiological Society and The Physiological Society.

  2. Australian shellfish ecosystems: Past distribution, current status and future direction.

    Chris L Gillies

    Full Text Available We review the status of marine shellfish ecosystems formed primarily by bivalves in Australia, including: identifying ecosystem-forming species, assessing their historical and current extent, causes for decline and past and present management. Fourteen species of bivalves were identified as developing complex, three-dimensional reef or bed ecosystems in intertidal and subtidal areas across tropical, subtropical and temperate Australia. A dramatic decline in the extent and condition of Australia's two most common shellfish ecosystems, developed by Saccostrea glomerata and Ostrea angasi oysters, occurred during the mid-1800s to early 1900s in concurrence with extensive harvesting for food and lime production, ecosystem modification, disease outbreaks and a decline in water quality. Out of 118 historical locations containing O. angasi-developed ecosystems, only one location still contains the ecosystem whilst only six locations are known to still contain S. glomerata-developed ecosystems out of 60 historical locations. Ecosystems developed by the introduced oyster Crasostrea gigas are likely to be increasing in extent, whilst data on the remaining 11 ecosystem-forming species are limited, preventing a detailed assessment of their current ecosystem-forming status. Our analysis identifies that current knowledge on extent, physical characteristics, biodiversity and ecosystem services of Australian shellfish ecosystems is extremely limited. Despite the limited information on shellfish ecosystems, a number of restoration projects have recently been initiated across Australia and we propose a number of existing government policies and conservation mechanisms, if enacted, would readily serve to support the future conservation and recovery of Australia's shellfish ecosystems.

  3. Australian shellfish ecosystems: Past distribution, current status and future direction

    Gillies, Chris L.; McLeod, Ian M.; Alleway, Heidi K.; Cook, Peter; Crawford, Christine; Creighton, Colin; Diggles, Ben; Ford, John; Hamer, Paul; Heller-Wagner, Gideon; Lebrault, Emma; Le Port, Agnès; Russell, Kylie; Sheaves, Marcus; Warnock, Bryn

    2018-01-01

    We review the status of marine shellfish ecosystems formed primarily by bivalves in Australia, including: identifying ecosystem-forming species, assessing their historical and current extent, causes for decline and past and present management. Fourteen species of bivalves were identified as developing complex, three-dimensional reef or bed ecosystems in intertidal and subtidal areas across tropical, subtropical and temperate Australia. A dramatic decline in the extent and condition of Australia’s two most common shellfish ecosystems, developed by Saccostrea glomerata and Ostrea angasi oysters, occurred during the mid-1800s to early 1900s in concurrence with extensive harvesting for food and lime production, ecosystem modification, disease outbreaks and a decline in water quality. Out of 118 historical locations containing O. angasi-developed ecosystems, only one location still contains the ecosystem whilst only six locations are known to still contain S. glomerata-developed ecosystems out of 60 historical locations. Ecosystems developed by the introduced oyster Crasostrea gigas are likely to be increasing in extent, whilst data on the remaining 11 ecosystem-forming species are limited, preventing a detailed assessment of their current ecosystem-forming status. Our analysis identifies that current knowledge on extent, physical characteristics, biodiversity and ecosystem services of Australian shellfish ecosystems is extremely limited. Despite the limited information on shellfish ecosystems, a number of restoration projects have recently been initiated across Australia and we propose a number of existing government policies and conservation mechanisms, if enacted, would readily serve to support the future conservation and recovery of Australia’s shellfish ecosystems. PMID:29444143

  4. Method for measuring the resistive transition and critical current in superconductors using pulsed current

    McGinnis, W.C.; Jones, T.E.

    1993-01-01

    A method is described for measuring the intragranular critical current of a granular superconductive material, comprising the steps of: conducting a substantially rectangular electronic pulse through said material so as to conduct a current through said material such that when said intragranular critical current of said material is exceeded, any grains present in said material are in a superconducting state when said current is less than said intragranular critical current, said material having a critical temperature; measuring said current through said material while conducting said pulse; measuring a voltage difference across said material while conducting said pulse; and determining said intragranular critical current through said material by varying said current to discern a current level at which an electrical resistance of said material increases to that of a non-superconducting state as the grains of said material transition from said superconducting to said non-superconducting state

  5. Direct measurements of the magnetic entropy change

    Nielsen, Kaspar Kirstein; Neves Bez, Henrique; von Moos, Lars

    2015-01-01

    An experimental device that can accurately measure the magnetic entropy change, Δs, as a function of temperature, T, and magnetic field, H, is presented. The magnetic field source is in this case a set of counter-rotating concentric Halbach-type magnets, which produce a highly homogeneous applied...... to the ambient are negligible in terms of the calorimetric determination of the magnetic entropy change, while the losses cannot be ignored when correcting for the actual sample temperature. We apply the device to two different types of samples; one is commercial grade Gd, i.e., a pure second-order phase...

  6. Water management: Current and future challenges and research directions

    Cosgrove, William J.; Loucks, Daniel P.

    2015-06-01

    Water distinguishes our planet compared to all the others we know about. While the global supply of available freshwater is more than adequate to meet all current and foreseeable water demands, its spatial and temporal distributions are not. There are many regions where our freshwater resources are inadequate to meet domestic, economic development and environmental needs. In such regions, the lack of adequate clean water to meet human drinking water and sanitation needs is indeed a constraint on human health and productivity and hence on economic development as well as on the maintenance of a clean environment and healthy ecosystems. All of us involved in research must find ways to remove these constraints. We face multiple challenges in doing that, especially given a changing and uncertain future climate, and a rapidly growing population that is driving increased social and economic development, globalization, and urbanization. How best to meet these challenges requires research in all aspects of water management. Since 1965, the journal Water Resources Research has played an important role in reporting and disseminating current research related to managing the quantity and quality and cost of this resource. This paper identifies the issues facing water managers today and future research needed to better inform those who strive to create a more sustainable and desirable future.

  7. Global fate of POPs: Current and future research directions

    Lohmann, Rainer; Breivik, Knut; Dachs, Jordi; Muir, Derek

    2007-01-01

    For legacy and emerging persistent organic pollutants (POPs), surprisingly little is still known in quantitative terms about their global sources and emissions. Atmospheric transport has been identified as the key global dispersal mechanism for most legacy POPs. In contrast, transport by ocean currents may prove to be the main transport route for many polar, emerging POPs. This is linked to the POPs' intrinsic physico-chemical properties, as exemplified by the different fate of hexachlorocyclohexanes in the Arctic. Similarly, our current understanding of POPs' global transport and fate remains sketchy. The importance of organic carbon and global temperature differences have been accepted as key drivers of POPs' global distribution. However, future research will need to understand the various biogeochemical and geophysical cycles under anthropogenic pressures to be able to understand and predict the global fate of POPs accurately. - Future studies into the global fate of POPs will need to pay more attention to the various biogeochemical and anthropogenic cycles to better understand emissions, transport and sinks

  8. Global fate of POPs: Current and future research directions

    Lohmann, Rainer [Graduate School of Oceanography, University of Rhode Island, Narragansett, RI 02882-1197 (United States)], E-mail: lohmann@gso.uri.edu; Breivik, Knut [Norwegian Institute for Air Research, PO Box 100, NO-2027 Kjeller (Norway); University of Oslo, Department of Chemistry, PO Box 1033, NO-0315 Oslo (Norway); Dachs, Jordi [Department of Environmental Chemistry, Institute of Chemical and Environmental Research (IIQAB-CSIC), Jordi Girona 18-26, Barcelona 08034 (Spain); Muir, Derek [Aquatic Ecosystem Protection Research Division, Environment Canada, 867 Lakeshore Road, Burlington, ON L7R4A6 (Canada)

    2007-11-15

    For legacy and emerging persistent organic pollutants (POPs), surprisingly little is still known in quantitative terms about their global sources and emissions. Atmospheric transport has been identified as the key global dispersal mechanism for most legacy POPs. In contrast, transport by ocean currents may prove to be the main transport route for many polar, emerging POPs. This is linked to the POPs' intrinsic physico-chemical properties, as exemplified by the different fate of hexachlorocyclohexanes in the Arctic. Similarly, our current understanding of POPs' global transport and fate remains sketchy. The importance of organic carbon and global temperature differences have been accepted as key drivers of POPs' global distribution. However, future research will need to understand the various biogeochemical and geophysical cycles under anthropogenic pressures to be able to understand and predict the global fate of POPs accurately. - Future studies into the global fate of POPs will need to pay more attention to the various biogeochemical and anthropogenic cycles to better understand emissions, transport and sinks.

  9. The MDSplus data acquisition system, current status and future directions

    Stillerman, J.; Fredian, T.W.

    1999-01-01

    The MDSplus data acquisition system was developed in collaboration with the ZTH group at Los Alamos National Laboratory and the RFX group at CNR in Padua, Italy and is currently in use at MIT, RFX in Padua, and TCV at EPFL in Lausanne. MDSplus is based on a hierarchical experiment description which completely describes the data acquisition and analysis tasks and contains the results from these operations. It also includes a set of X/motif based tools for data acquisition and display, as well as diagnostic configuration and management. These tools were designed to operate in a distributed, client/server environment with multiple concurrent readers and writers to the data store. An interface to a relational database is provided for storage and management of processed data. A commercially available package called IDL is used as the primary data analysis and visualization tool. The current projects include a new interface to the electronic logbook, tools for remote collaborators and WWW access, and a port of the system to UNIX and Windows-NT/95. (orig.)

  10. Toward Direct Reaction-in-Flight Measurements

    Wilhelmy, Jerry; Bredeweg, Todd; Fowler, Malcolm; Gooden, Matthew; Hayes, Anna; Rusev, Gencho; Caggiano, Joseph; Hatarik, Robert; Henry, Eugene; Tonchev, Anton; Yeaman, Charles; Bhike, Megha; Krishichayan, Krishi; Tornow, Werner

    2016-03-01

    At the National Ignition Facility (NIF) neutrons having energies greater than the equilibrium 14.1 MeV value can be produced via Reaction-in-Flight (RIF) interactions between plasma atoms and upscattered D or T ions. The yield and spectrum of these RIF produced neutrons carry information on the plasma properties as well as information on the stopping power of ions under plasma conditions. At NIF the yield of these RIF neutrons is predicted to be 4-7 orders of magnitude below the peak 14 MeV neutron yield. The current generation of neutron time of flight (nTOF) instrumentation has so far been incapable of detecting these low-yield neutrons primarily due to high photon backgrounds. To date, information on RIF neutrons has been obtained in integral activation experiments using reactions with high energy thresholds such as 169Tm(n,3n)167Tm and 209Bi(n,4n) 206Bi. Initial experiments to selectively suppress photon backgrounds have been performed at TUNL using pulsed monoenergetic neutron beams of 14.9, 18.5, 24.2, and 28.5 MeV impinging on a Bibenzyl scintillator. By placing 5 cm of Pb before the scintillator we were able to selectively suppress the photons from the flash occurring at the production target and enhance the n/_signal by ~6 times.

  11. Impression management and food intake. Current directions in research.

    Vartanian, Lenny R

    2015-03-01

    This paper reviews recent research on consumption stereotypes (judgments of others based on what they eat) and impression management (modifying one's eating behavior in order to create a particular impression). A major recent focus in the literature has been on masculinity and meat eating, with research showing that meat is strongly associated with masculinity, and that individuals who follow a meat-based diet are perceived as more masculine than are individuals who follow a vegetarian diet. Although direct evidence for impression management through food intake remains sparse, a number of methodological approaches (including priming techniques and ecological valid assessments) are described that could be used in future research to identify the motives underlying people's eating behavior. Consumption stereotypes and impression management may be important influences on people's eating behavior, but the complexities of how, when, and for whom these factors influence food intake are still not well understood. Copyright © 2014 Elsevier Ltd. All rights reserved.

  12. Sustainable supply chain management: current debate and future directions

    Bruno Silvestre

    Full Text Available Abstract This paper is a research brief on sustainable supply chain management and covers some of the key elements of literature’s past debate and trends for future directions. It highlights the growth of this research area and reinforces the importance of a full consideration of all three key dimensions of sustainability when managing sustainable supply chains, i.e., the financial, environmental and social dimensions. Therefore, supply chain decision makers need to unequivocally assess the impact of their decisions on the financial, environmental and social performances of their supply chains. This paper also argues that risks and opportunities are the key drivers for supply chain decision makers to adopt sustainability within their operations, and that barriers to sustainability adoption exist. This research highlights that, depending on the focus adopted, supply chains can evolve and shift from more traditional to more sustainable approaches over time. The paper concludes with some promising avenues for future investigation.

  13. Reducing hospital readmission rates: current strategies and future directions.

    Kripalani, Sunil; Theobald, Cecelia N; Anctil, Beth; Vasilevskis, Eduard E

    2014-01-01

    New financial penalties for institutions with high readmission rates have intensified efforts to reduce rehospitalization. Several interventions that involve multiple components (e.g., patient needs assessment, medication reconciliation, patient education, arranging timely outpatient appointments, and providing telephone follow-up) have successfully reduced readmission rates for patients discharged to home. The effect of interventions on readmission rates is related to the number of components implemented; single-component interventions are unlikely to reduce readmissions significantly. For patients discharged to postacute care facilities, multicomponent interventions have reduced readmissions through enhanced communication, medication safety, advanced care planning, and enhanced training to manage medical conditions that commonly precipitate readmission. To help hospitals direct resources and services to patients with greater likelihood of readmission, risk-stratification methods are available. Future work should better define the roles of home-based services, information technology, mental health care, caregiver support, community partnerships, and new transitional care personnel.

  14. Treating Alopecia Areata: Current Practices Versus New Directions.

    Gupta, Aditya K; Carviel, Jessie; Abramovits, William

    2017-02-01

    Alopecia areata (AA) is non-scarring hair loss resulting from an autoimmune disorder. Severity varies from patchy hair loss that often spontaneously resolves to severe and chronic cases that can progress to total loss of scalp and body hair. Many treatments are available; however, the efficacy of these treatments has not been confirmed, especially in severe cases, and relapse rates are high. First-line treatment often includes corticosteroids such as intralesional or topical steroids for mild cases and systemic steroids or topical immunotherapy with diphenylcyclopropenone or squaric acid dibutylester in severe cases. Minoxidil and bimatoprost may also be recommended, usually in combination with another treatment. Ongoing research and new insights into mechanisms have led to proposals of innovative therapies. New directions include biologics targeting immune response as well as lasers and autologous platelet-rich plasma therapy. Preliminary data are encouraging, and it is hoped this research will translate into new options for the treatment of AA in the near future.

  15. Spreading depolarizations have prolonged direct current shifts and are associated with poor outcome in brain trauma

    Hartings, Jed A; Watanabe, Tomas; Bullock, M Ross

    2011-01-01

    , although prolonged events have not been observed in animal models. To determine whether detrimental penumbral-type depolarizations occur in human brain trauma, we analysed electrocorticographic recordings obtained by subdural electrode-strip monitoring during intensive care. Of 53 patients studied, 10......Cortical spreading depolarizations occur spontaneously after ischaemic, haemorrhagic and traumatic brain injury. Their effects vary spatially and temporally as graded phenomena, from infarction to complete recovery, and are reflected in the duration of depolarization measured by the negative direct...... current shift of electrocorticographic recordings. In the focal ischaemic penumbra, peri-infarct depolarizations have prolonged direct current shifts and cause progressive recruitment of the penumbra into the core infarct. In traumatic brain injury, the effects of spreading depolarizations are unknown...

  16. Cyberbullying Prevention and Intervention Efforts: Current Knowledge and Future Directions

    Hong, Jun Sung

    2016-01-01

    Bullying is a serious public health concern that is associated with significant negative mental, social, and physical outcomes. Technological advances have increased adolescents’ use of social media, and online communication platforms have exposed adolescents to another mode of bullying—cyberbullying. Prevention and intervention materials, from websites and tip sheets to classroom curriculum, have been developed to help youth, parents, and teachers address cyberbullying. While youth and parents are willing to disclose their experiences with bullying to their health care providers, these disclosures need to be taken seriously and handled in a caring manner. Health care providers need to include questions about bullying on intake forms to encourage these disclosures. The aim of this article is to examine the current status of cyberbullying prevention and intervention. Research support for several school-based intervention programs is summarised. Recommendations for future research are provided. PMID:28562094

  17. Transcranial Magnetic Stimulation in Child Neurology: Current and Future Directions

    Frye, Richard E.; Rotenberg, Alexander; Ousley, Molliann; Pascual-Leone, Alvaro

    2008-01-01

    Transcranial magnetic stimulation (TMS) is a method for focal brain stimulation based on the principle of electromagnetic induction, where small intracranial electric currents are generated by a powerful, rapidly changing extracranial magnetic field. Over the past 2 decades TMS has shown promise in the diagnosis, monitoring, and treatment of neurological and psychiatric disease in adults, but has been used on a more limited basis in children. We reviewed the literature to identify potential diagnostic and therapeutic applications of TMS in child neurology and also its safety in pediatrics. Although TMS has not been associated with any serious side effects in children and appears to be well tolerated, general safety guidelines should be established. The potential for applications of TMS in child neurology and psychiatry is significant. Given its excellent safety profile and possible therapeutic effect, this technique should develop as an important tool in pediatric neurology over the next decade. PMID:18056688

  18. Cyberbullying Prevention and Intervention Efforts: Current Knowledge and Future Directions.

    Espelage, Dorothy L; Hong, Jun Sung

    2017-06-01

    Bullying is a serious public health concern that is associated with significant negative mental, social, and physical outcomes. Technological advances have increased adolescents' use of social media, and online communication platforms have exposed adolescents to another mode of bullying- cyberbullying. Prevention and intervention materials, from websites and tip sheets to classroom curriculum, have been developed to help youth, parents, and teachers address cyberbullying. While youth and parents are willing to disclose their experiences with bullying to their health care providers, these disclosures need to be taken seriously and handled in a caring manner. Health care providers need to include questions about bullying on intake forms to encourage these disclosures. The aim of this article is to examine the current status of cyberbullying prevention and intervention. Research support for several school-based intervention programs is summarised. Recommendations for future research are provided.

  19. Transformational leadership in sport: current status and future directions.

    Arthur, Calum A; Bastardoz, Nicolas; Eklund, Robert

    2017-08-01

    Borrowed from organizational psychology, the concept of transformational leadership has now been applied to a sport context for a decade. Our review covers and critically discusses empirical articles published on this growing topic. However, because the majority of studies used cross-sectional designs and single-source questionnaires to tap what has been a fuzzy construct, current theoretical and methodological issues impede understanding of whether transformational leadership matters for sport outcomes. To make a difference to applied practice and policy, the transformational leadership construct requires a refined definition and stronger empirical tests allowing for robust causal inference. We highlight avenues for advancing research on transformational leadership in the sport context. Crown Copyright © 2017. Published by Elsevier Ltd. All rights reserved.

  20. Female sex trafficking: conceptual issues, current debates, and future directions.

    Meshkovska, Biljana; Siegel, Melissa; Stutterheim, Sarah E; Bos, Arjan E R

    2015-01-01

    Female sex trafficking is a pressing concern. In this article, we provide a comprehensive overview of relevant issues regarding the concept of female sex trafficking and research in the field of human trafficking, drawing on a variety of disciplines, including economics, gender and sexuality studies, psychology, sociology, law, and social work. We discuss the debates surrounding the definition of human trafficking, compare and contrast it with human smuggling, and outline connections between female sex trafficking and the issue of sex work and prostitution. We further discuss the history and current estimations of female sex trafficking. We then outline the main actors in female sex trafficking, including trafficked persons, traffickers, clients, and service providers, and we overview the trafficking process from recruitment to identification, recovery, and (re)integration. Finally, we conclude with recommendations for future research that tie together the concepts of vulnerability, exploitation, and long-term recovery and (re)integration.

  1. Nuclear disasters: current plans and future directions for oncologists.

    Goffman, Thomas E

    2008-01-01

    To show that there is a significant role for oncologists in the event of a terrorist nuclear disaster. Professionals need data on current political issues regarding a nuclear attack already put in place by the administration and the military. Review of what actually occurs during a fission bomb's explosion helps to point out what medical care will be most needed. The author contends that those trained in the oncologies could play a major part. Modern-day America. Potential civilian survivors. Large gaps noted in statewide disaster plans in the public domain. Oncologists must get involved now in disaster planning; statewide plans are necessary throughout the nation; the public needs to know the basics of what to do in the advent of a nuclear bomb explosion.

  2. Fontan Surgical Planning: Previous Accomplishments, Current Challenges, and Future Directions.

    Trusty, Phillip M; Slesnick, Timothy C; Wei, Zhenglun Alan; Rossignac, Jarek; Kanter, Kirk R; Fogel, Mark A; Yoganathan, Ajit P

    2018-04-01

    The ultimate goal of Fontan surgical planning is to provide additional insights into the clinical decision-making process. In its current state, surgical planning offers an accurate hemodynamic assessment of the pre-operative condition, provides anatomical constraints for potential surgical options, and produces decent post-operative predictions if boundary conditions are similar enough between the pre-operative and post-operative states. Moving forward, validation with post-operative data is a necessary step in order to assess the accuracy of surgical planning and determine which methodological improvements are needed. Future efforts to automate the surgical planning process will reduce the individual expertise needed and encourage use in the clinic by clinicians. As post-operative physiologic predictions improve, Fontan surgical planning will become an more effective tool to accurately model patient-specific hemodynamics.

  3. Microneedles for Transdermal Biosensing: Current Picture and Future Direction.

    Ventrelli, Letizia; Marsilio Strambini, Lucanos; Barillaro, Giuseppe

    2015-12-09

    A novel trend is rapidly emerging in the use of microneedles, which are a miniaturized replica of hypodermic needles with length-scales of hundreds of micrometers, aimed at the transdermal biosensing of analytes of clinical interest, e.g., glucose, biomarkers, and others. Transdermal biosensing via microneedles offers remarkable opportunities for moving biosensing technologies and biochips from research laboratories to real-field applications, and envisages easy-to-use point-of-care microdevices with pain-free, minimally invasive, and minimal-training features that are very attractive for both developed and emerging countries. In addition to this, microneedles for transdermal biosensing offer a unique possibility for the development of biochips provided with end-effectors for their interaction with the biological system under investigation. Direct and efficient collection of the biological sample to be analyzed will then become feasible in situ at the same length-scale of the other biochip components by minimally trained personnel and in a minimally invasive fashion. This would eliminate the need for blood extraction using hypodermic needles and reduce, in turn, related problems, such as patient infections, sample contaminations, analysis artifacts, etc. The aim here is to provide a thorough and critical analysis of state-of-the-art developments in this novel research trend, and to bridge the gap between microneedles and biosensors. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  4. Neuropsychological effects of cranial radiation: current knowledge and future directions

    Roman, Deborah D.; Sperduto, Paul W.

    1995-01-01

    Radiation is an invaluable therapeutic tool in the treatment of cancer, with well-established palliative and curative efficacy. As patient survival has improved, attention has focused on long-range treatment side effects. One such adverse effect, neuropsychological impairment, is incompletely understood. Much of the extant research has been directed at childhood leukemia survivors treated with low-dose whole-brain radiation. Less is known about the effects of high-dose focal or whole-brain radiation used in the treatment of brain lesions. This article reviews the scientific literature in this area, with greatest emphasis on methodologically rigorous studies. Research design considerations are discussed. Review findings suggest that low-dose whole-brain radiation (18 to 24 Gy) in children is associated with mild delayed IQ decline, with more substantial deficits occurring in children treated at a young age. A high incidence of learning disabilities and academic failure is observed in this population and may be caused by poor attention and memory rather than low intellectual level. Children who receive higher dose radiation for treatment of brain tumors experience more pronounced cognitive decline. At higher doses, whole-brain radiation, in particular, is linked to deleterious cognitive outcomes. Remarkably little is known about cognitive outcomes in irradiated adults. Preliminary findings indicate that certain cognitive functions, including memory, may be more vulnerable to decline than others. Suggestions for future research are proposed

  5. Current status and directions for fast reactor reprocessing

    Burch, W.D.

    1983-01-01

    The development of fast breeder reactors (FBRs) for commercial electric power production has been under way in several countries for more than 20 years. In the United States as elsewhere, early work was centered on small reactors to prove the feasibility of concepts and later was followed by larger reactors to test engineering features and to develop fuel technology. In the early 1970s, with the perceived crisis in electrical generation expected late in this century, major efforts were mounted to plan and carry out comprehensive development programs to ensure the capability to develop and begin using this new form of nuclear power by the end of this century. This comprehensive effort included the first serious efforts directed toward the supporting fuel cycle activities. However, because of the effects of the oil price rise and resulting conservation, a slowdown of industrial growth, and cut-backs in energy needs, there has been a decline in program activities. Unlike the fuel cycle for light-water reactors (LWRs), where supply and the back-end recycle and/or waste disposal activities can largely be uncoupled, recovery and recycle of fissile materials in spent fuel must be accomplished in one or two years in a practical breeder system. 3 references

  6. Transcranial direct current stimulation over left inferior frontal cortex improves speech fluency in adults who stutter.

    Chesters, Jennifer; Möttönen, Riikka; Watkins, Kate E

    2018-04-01

    See Crinion (doi:10.1093/brain/awy075) for a scientific commentary on this article.Stuttering is a neurodevelopmental condition affecting 5% of children, and persisting in 1% of adults. Promoting lasting fluency improvement in adults who stutter is a particular challenge. Novel interventions to improve outcomes are of value, therefore. Previous work in patients with acquired motor and language disorders reported enhanced benefits of behavioural therapies when paired with transcranial direct current stimulation. Here, we report the results of the first trial investigating whether transcranial direct current stimulation can improve speech fluency in adults who stutter. We predicted that applying anodal stimulation to the left inferior frontal cortex during speech production with temporary fluency inducers would result in longer-lasting fluency improvements. Thirty male adults who stutter completed a randomized, double-blind, controlled trial of anodal transcranial direct current stimulation over left inferior frontal cortex. Fifteen participants received 20 min of 1-mA stimulation on five consecutive days while speech fluency was temporarily induced using choral and metronome-timed speech. The other 15 participants received the same speech fluency intervention with sham stimulation. Speech fluency during reading and conversation was assessed at baseline, before and after the stimulation on each day of the 5-day intervention, and at 1 and 6 weeks after the end of the intervention. Anodal stimulation combined with speech fluency training significantly reduced the percentage of disfluent speech measured 1 week after the intervention compared with fluency intervention alone. At 6 weeks after the intervention, this improvement was maintained during reading but not during conversation. Outcome scores at both post-intervention time points on a clinical assessment tool (the Stuttering Severity Instrument, version 4) also showed significant improvement in the group receiving

  7. SQUID based cryogenic current comparator for measurements of the dark current of superconducting cavities

    Vodel, W.; Nietzsche, S.; Neubert, R.; Nawrodt, R. [Friedrich Schiller Univ. Jena (Germany); Peters, A. [GSI Darmstadt (Germany); Knaack, K.; Wendt, M.; Wittenburg, K. [DESY Hamburg (Germany)

    2005-07-01

    The linear accelerator technology, based on super-conducting L-band (1.3 GHz) is currently under study at DESY (Hamburg, Germany). The two 10 km long main Linacs will be equipped with a total of nearly 20.000 cavities. The dark current due to the emission of electrons in these high gradient field super-conducting cavities is an unwanted particle source. A newly high performance SQUID based measurement system for detecting dark currents is proposed. It makes use of the Cryogenic Current Comparator principle and senses dark currents in the pA range with a measurement bandwidth of up to 70 kHz. The use of a cryogenic current comparator as dark current sensor has some important advantages: -) the measurement of the absolute value of the dark current, -) the non-dependence on the electron trajectories, -) the accurate absolute calibration with an additional wire loop, and -) extremely high resolution.

  8. Phocine distemper virus: current knowledge and future directions.

    Duignan, Pádraig J; Van Bressem, Marie-Françoise; Baker, Jason D; Barbieri, Michelle; Colegrove, Kathleen M; De Guise, Sylvain; de Swart, Rik L; Di Guardo, Giovanni; Dobson, Andrew; Duprex, W Paul; Early, Greg; Fauquier, Deborah; Goldstein, Tracey; Goodman, Simon J; Grenfell, Bryan; Groch, Kátia R; Gulland, Frances; Hall, Ailsa; Jensen, Brenda A; Lamy, Karina; Matassa, Keith; Mazzariol, Sandro; Morris, Sinead E; Nielsen, Ole; Rotstein, David; Rowles, Teresa K; Saliki, Jeremy T; Siebert, Ursula; Waltzek, Thomas; Wellehan, James F X

    2014-12-22

    Phocine distemper virus (PDV) was first recognized in 1988 following a massive epidemic in harbor and grey seals in north-western Europe. Since then, the epidemiology of infection in North Atlantic and Arctic pinnipeds has been investigated. In the western North Atlantic endemic infection in harp and grey seals predates the European epidemic, with relatively small, localized mortality events occurring primarily in harbor seals. By contrast, PDV seems not to have become established in European harbor seals following the 1988 epidemic and a second event of similar magnitude and extent occurred in 2002. PDV is a distinct species within the Morbillivirus genus with minor sequence variation between outbreaks over time. There is now mounting evidence of PDV-like viruses in the North Pacific/Western Arctic with serological and molecular evidence of infection in pinnipeds and sea otters. However, despite the absence of associated mortality in the region, there is concern that the virus may infect the large Pacific harbor seal and northern elephant seal populations or the endangered Hawaiian monk seals. Here, we review the current state of knowledge on PDV with particular focus on developments in diagnostics, pathogenesis, immune response, vaccine development, phylogenetics and modeling over the past 20 years.

  9. Collagen Cross-Linking: Current Status and Future Directions

    Marine Hovakimyan

    2012-01-01

    Full Text Available Collagen cross-linking (CXL using UVA light and riboflavin (vitamin B2 was introduced as a clinical application to stabilize the cornea by inducing cross-links within and between collagen fibers. CXL has been investigated extensively and has been shown clinically to arrest the progression of keratoconic or post-LASIK ectasia. With its minimal cost, simplicity, and proven positive clinical outcome, CXL can be regarded as a useful approach to reduce the number of penetrating keratoplasties performed. Small case series have also indicated that CXL is beneficial in corneal edema by reducing stromal swelling behavior and in keratitis by inhibiting pathogen growth. Despite these encouraging results, CXL remains a relatively new method that is potentially associated with complications. Aspects such as side effects and recurrence rates have still to be elucidated. In light of the growing interest in CXL, our paper summarizes present knowledge about this promising approach. We have intentionally endeavored to include the more relevant studies from the recent literature to provide an overview of the current status of CXL.

  10. Current status and directions for fast reactor reprocessing

    Burch, W.D.

    1983-01-01

    The development of fast breeder reactors (FBRs) for commercial electric power production has been under way in several countries for more than 20 years. In the United States (US), as elsewhere, early work was focused on small reactors to prove the feasibility of concepts and later was followed by larger reactors to test engineering features and to develop fuel technology. Because of the perceived crisis in electrical generation expected late in this century, major efforts (including fuel cycle activities) were developed in the early 1970s to ensure the capability of developing and using this new form of nuclear power. However, because of the effects of the oil price rise and subsequent emphasis on conservation, and a slowdown of industrial growth, there has been a decline in such activities, particularly in the US, which was at one time (1970s) the world leader in reactor development. This paper provides a brief history of breeder reprocessing and describes the current status, with emphasis on US programs and glimpses into the future

  11. The Evolution of Process Safety: Current Status and Future Direction.

    Mannan, M Sam; Reyes-Valdes, Olga; Jain, Prerna; Tamim, Nafiz; Ahammad, Monir

    2016-06-07

    The advent of the industrial revolution in the nineteenth century increased the volume and variety of manufactured goods and enriched the quality of life for society as a whole. However, industrialization was also accompanied by new manufacturing and complex processes that brought about the use of hazardous chemicals and difficult-to-control operating conditions. Moreover, human-process-equipment interaction plus on-the-job learning resulted in further undesirable outcomes and associated consequences. These problems gave rise to many catastrophic process safety incidents that resulted in thousands of fatalities and injuries, losses of property, and environmental damages. These events led eventually to the necessity for a gradual development of a new multidisciplinary field, referred to as process safety. From its inception in the early 1970s to the current state of the art, process safety has come to represent a wide array of issues, including safety culture, process safety management systems, process safety engineering, loss prevention, risk assessment, risk management, and inherently safer technology. Governments and academic/research organizations have kept pace with regulatory programs and research initiatives, respectively. Understanding how major incidents impact regulations and contribute to industrial and academic technology development provides a firm foundation to address new challenges, and to continue applying science and engineering to develop and implement programs to keep hazardous materials within containment. Here the most significant incidents in terms of their impact on regulations and the overall development of the field of process safety are described.

  12. Microorganisms in Fermented Apple Beverages: Current Knowledge and Future Directions.

    Cousin, Fabien J; Le Guellec, Rozenn; Schlusselhuber, Margot; Dalmasso, Marion; Laplace, Jean-Marie; Cretenet, Marina

    2017-07-25

    Production of fermented apple beverages is spread all around the world with specificities in each country. 'French ciders' refer to fermented apple juice mainly produced in the northwest of France and often associated with short periods of consumption. Research articles on this kind of product are scarce compared to wine, especially on phenomena associated with microbial activities. The wine fermentation microbiome and its dynamics, organoleptic improvement for healthy and pleasant products and development of starters are now widely studied. Even if both beverages seem close in terms of microbiome and process (with both alcoholic and malolactic fermentations), the inherent properties of the raw materials and different production and environmental parameters make research on the specificities of apple fermentation beverages worthwhile. This review summarizes current knowledge on the cider microbial ecosystem, associated activities and the influence of process parameters. In addition, available data on cider quality and safety is reviewed. Finally, we focus on the future role of lactic acid bacteria and yeasts in the development of even better or new beverages made from apples.

  13. Osteoporosis in older persons: current pharmacotherapy and future directions.

    Duque, Gustavo

    2013-10-01

    Osteopororic fractures are highly prevalent in older persons having catastrophic consequences in their quality of life and increasing disability and mortality in this population. The mechanisms of osteoporosis in older persons are unique in terms of cellular changes and response to osteoporosis treatment. Therefore, specifically targeted treatments are required in this particular population. This paper provides an overview on the particular mechanisms of osteoporosis in older persons and the current and future therapeutic strategies to improve bone mass and prevent fractures in this population. Osteoporosis in older persons (especially in the old-old) has a unique pathophysiology that predisposes them to fractures thus having catastrophic consequences. Identification of patients at risk followed by therapies targeted to their cellular changes is pivotal to close the care gap observed in osteoporosis, predominantly in the older population. The treatment of osteoporosis has evolved from daily to yearly dosing thus facilitating compliance and effectiveness. It is expected that future biologically targeted treatments will have a similar separate dosing regime with better anti-fracture efficacy and lower incidence of side effects.

  14. Acute myeloid leukemia in children: Current status and future directions.

    Taga, Takashi; Tomizawa, Daisuke; Takahashi, Hiroyuki; Adachi, Souichi

    2016-02-01

    Acute myeloid leukemia (AML) accounts for 25% of pediatric leukemia and affects approximately 180 patients annually in Japan. The treatment outcome for pediatric AML has improved through advances in chemotherapy, hematopoietic stem cell transplantation (HSCT), supportive care, and optimal risk stratification. Currently, clinical pediatric AML studies are conducted separately according to the AML subtypes: de novo AML, acute promyelocytic leukemia (APL), and myeloid leukemia with Down syndrome (ML-DS). Children with de novo AML are treated mainly with anthracyclines and cytarabine, in some cases with HSCT, and the overall survival (OS) rate now approaches 70%. Children with APL are treated with an all-trans retinoic acid (ATRA)-combined regimen with an 80-90% OS. Children with ML-DS are treated with a less intensive regimen compared with non-DS patients, and the OS is approximately 80%. HSCT in first remission is restricted to children with high-risk de novo AML only. To further improve outcomes, it will be necessary to combine more accurate risk stratification strategies using molecular genetic analysis with assessment of minimum residual disease, and the introduction of new drugs in international collaborative clinical trials. © 2015 Japan Pediatric Society.

  15. Phocine Distemper Virus: Current Knowledge and Future Directions

    Pádraig J. Duignan

    2014-12-01

    Full Text Available Phocine distemper virus (PDV was first recognized in 1988 following a massive epidemic in harbor and grey seals in north-western Europe. Since then, the epidemiology of infection in North Atlantic and Arctic pinnipeds has been investigated. In the western North Atlantic endemic infection in harp and grey seals predates the European epidemic, with relatively small, localized mortality events occurring primarily in harbor seals. By contrast, PDV seems not to have become established in European harbor seals following the 1988 epidemic and a second event of similar magnitude and extent occurred in 2002. PDV is a distinct species within the Morbillivirus genus with minor sequence variation between outbreaks over time. There is now mounting evidence of PDV-like viruses in the North Pacific/Western Arctic with serological and molecular evidence of infection in pinnipeds and sea otters. However, despite the absence of associated mortality in the region, there is concern that the virus may infect the large Pacific harbor seal and northern elephant seal populations or the endangered Hawaiian monk seals. Here, we review the current state of knowledge on PDV with particular focus on developments in diagnostics, pathogenesis, immune response, vaccine development, phylogenetics and modeling over the past 20 years.

  16. Munchausen by internet: current research and future directions.

    Pulman, Andy; Taylor, Jacqui

    2012-08-22

    also suggest directions for future research.

  17. Direct measurement of tritium in urine by liquid scintillation method

    Zhang Caihong; Wen Qinghua; Chen Kefei; Li Huaixin

    1999-01-01

    The author introduces the method for direct measurement of tritium concentration in urine using liquid scintillation. Effects of sampling containers, store patterns and storage time are studied. Meanwhile, results of two methods are compared with direct measurement method and oxidation distillation method. The results shows that direct measurement method is a economic and simple method, which can meet the need of determination of urine tritium for NPP workers. There is no significant difference compared with the data obtained by oxidation distillation method

  18. CRISPR technologies for bacterial systems: Current achievements and future directions.

    Choi, Kyeong Rok; Lee, Sang Yup

    2016-11-15

    Throughout the decades of its history, the advances in bacteria-based bio-industries have coincided with great leaps in strain engineering technologies. Recently unveiled clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR-associated proteins (Cas) systems are now revolutionizing biotechnology as well as biology. Diverse technologies have been derived from CRISPR/Cas systems in bacteria, yet the applications unfortunately have not been actively employed in bacteria as extensively as in eukaryotic organisms. A recent trend of engineering less explored strains in industrial microbiology-metabolic engineering, synthetic biology, and other related disciplines-is demanding facile yet robust tools, and various CRISPR technologies have potential to cater to the demands. Here, we briefly review the science in CRISPR/Cas systems and the milestone inventions that enabled numerous CRISPR technologies. Next, we describe CRISPR/Cas-derived technologies for bacterial strain development, including genome editing and gene expression regulation applications. Then, other CRISPR technologies possessing great potential for industrial applications are described, including typing and tracking of bacterial strains, virome identification, vaccination of bacteria, and advanced antimicrobial approaches. For each application, we note our suggestions for additional improvements as well. In the same context, replication of CRISPR/Cas-based chromosome imaging technologies developed originally in eukaryotic systems is introduced with its potential impact on studying bacterial chromosomal dynamics. Also, the current patent status of CRISPR technologies is reviewed. Finally, we provide some insights to the future of CRISPR technologies for bacterial systems by proposing complementary techniques to be developed for the use of CRISPR technologies in even wider range of applications. Copyright © 2016. Published by Elsevier Inc.

  19. The European Drought Observatory (EDO): Current State and Future Directions

    Vogt, Jürgen; Sepulcre, Guadalupe; Magni, Diego; Valentini, Luana; Singleton, Andrew; Micale, Fabio; Barbosa, Paulo

    2013-04-01

    Europe has repeatedly been affected by droughts, resulting in considerable ecological and economic damage and climate change studies indicate a trend towards increasing climate variability most likely resulting in more frequent drought occurrences also in Europe. Against this background, the European Commission's Joint Research Centre (JRC) is developing methods and tools for assessing, monitoring and forecasting droughts in Europe and develops a European Drought Observatory (EDO) to complement and integrate national activities with a European view. At the core of the European Drought Observatory (EDO) is a portal, including a map server, a metadata catalogue, a media-monitor and analysis tools. The map server presents Europe-wide up-to-date information on the occurrence and severity of droughts, which is complemented by more detailed information provided by regional, national and local observatories through OGC compliant web mapping and web coverage services. In addition, time series of historical maps as well as graphs of the temporal evolution of drought indices for individual grid cells and administrative regions in Europe can be retrieved and analysed. Current work is focusing on validating the available products, developing combined indicators, improving the functionalities, extending the linkage to additional national and regional drought information systems and testing options for medium-range probabilistic drought forecasting across Europe. Longer-term goals include the development of long-range drought forecasting products, the analysis of drought hazard and risk, the monitoring of drought impact and the integration of EDO in a global drought information system. The talk will provide an overview on the development and state of EDO, the different products, and the ways to include a wide range of stakeholders (i.e. European, national river basin, and local authorities) in the development of the system as well as an outlook on the future developments.

  20. Systemic Immunotherapy for Urothelial Cancer: Current Trends and Future Directions

    Shilpa Gupta

    2017-01-01

    Full Text Available Urothelial cancer of the bladder, renal pelvis, ureter, and other urinary organs is the fifth most common cancer in the United States, and systemic platinum-based chemotherapy remains the standard of care for first-line treatment of advanced/metastatic urothelial carcinoma (UC. Until recently, there were very limited options for patients who are refractory to chemotherapy, or do not tolerate chemotherapy due to toxicities and overall outcomes have remained very poor. While the role of immunotherapy was first established in non-muscle invasive bladder cancer in the 1970s, no systemic immunotherapy was approved for advanced disease until the recent approval of a programmed death ligand-1 (PD-L1 inhibitor, atezolizumab, in patients with advanced/metastatic UC who have progressed on platinum-containing regimens. This represents a significant milestone in this disease after a void of over 30 years. In addition to atezolizumab, a variety of checkpoint inhibitors have shown a significant activity in advanced/metastatic urothelial carcinoma and are expected to gain Food and Drug Administration (FDA approval in the near future. The introduction of novel immunotherapy agents has led to rapid changes in the field of urothelial carcinoma. Numerous checkpoint inhibitors are being tested alone or in combination in the first and subsequent-line therapies of metastatic disease, as well as neoadjuvant and adjuvant settings. They are also being studied in combination with radiation therapy and for non-muscle invasive bladder cancer refractory to BCG. Furthermore, immunotherapy is being utilized for those ineligible for firstline platinum-based chemotherapy. This review outlines the novel immunotherapy agents which have either been approved, or are currently being investigated in clinical trials in UC.

  1. Development of a Direct Methanol Fuel Cell with Lightweight Disc Type Current Collectors

    Yean-Der Kuan

    2014-05-01

    Full Text Available The direct methanol fuel cell (DMFC adopts methanol solution as a fuel suitable for low power portable applications. A miniature, lightweight, passive air-breathing design is therefore desired. This paper presents a novel planar disc-type DMFC with multiple cells containing a novel developed lightweight current collector at both the anode and cathode sides. The present lightweight current collector adopts FR4 Glass/Epoxy as the substrate with the current collecting areas located at the corresponding membrane electrolyte assembly (MEA areas. The current collecting areas are fabricated by sequentially coating a corrosion resistant layer and electrical conduction layer via the thermal evaporation technique. The anode current collector has carved flow channels for fuel transport and production. The cathode current collector has drilled holes for passive air breathing. In order to ensure feasibility in the present concept a 3-cell prototype DMFC module with lightweight disc type current collectors is designed and constructed. Experiments were conducted to measure the cell performance. The results show that the highest cell power output is 54.88 mW·cm−2 and successfully demonstrate the feasibility of this novel design.

  2. Current management of diabetes mellitus and future directions in care.

    Chatterjee, Sudesna; Davies, Melanie J

    2015-11-01

    outcomes, but macrovascular outcomes and cardiovascular safety remain controversial with several glucose-lowering agents. Future directions in diabetes care include strategies such as the 'bionic pancreas', stem cell therapy and targeting the intestinal microbiome. All of these treatments are still being refined, and it may be several decades before they are clinically useful. Prevention and cure of diabetes is the Holy Grail but remain elusive due to lack of detailed understanding of the metabolic, genetic and immunological causes that underpin diabetes. Much progress has been made since the time of Prof MacLean 90 years ago, but there are still great strides to be taken before the life of the patient with diabetes improves even more significantly. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/

  3. Transcranial direct current stimulation in patients with Alzheimer’s disease: Challenges and responses

    Hong Yuan

    2015-09-01

    Full Text Available The use of transcranial direct current stimulation (tDCS as a noninvasive therapeutic approach for Alzheimer’s disease (AD has gained increasing attention. Research regarding the utility of tDCS in AD is inconsistent. In this study, we reviewed the importance of individual diversity among AD patients, starting from the uninformative mean results. We also demonstrated variation among AD patients. Highly educated patients seem to benefit more; education also seems to modulate baseline measurements and the results. Individual cortical morphology also affects the current distribution, which influences the effectiveness of stimulation. We suggest the use of structural MRI to distinguish inter-individual variability; high-resolution modeling can also be used to predict current distributions and should be combined with cognitive training (CT along with tDCS.

  4. Is transcranial direct current stimulation a potential method for improving response inhibition?

    Kwon, Yong Hyun; Kwon, Jung Won

    2013-04-15

    Inhibitory control of movement in motor learning requires the ability to suppress an inappropriate action, a skill needed to stop a planned or ongoing motor response in response to changes in a variety of environments. This study used a stop-signal task to determine whether transcranial direct-current stimulation over the pre-supplementary motor area alters the reaction time in motor inhibition. Forty healthy subjects were recruited for this study and were randomly assigned to either the transcranial direct-current stimulation condition or a sham-transcranial direct-current stimulation condition. All subjects consecutively performed the stop-signal task before, during, and after the delivery of anodal transcranial direct-current stimulation over the pre-supplementary motor area (pre-transcranial direct-current stimulation phase, transcranial direct-current stimulation phase, and post-transcranial direct-current stimulation phase). Compared to the sham condition, there were significant reductions in the stop-signal processing times during and after transcranial direct-current stimulation, and change times were significantly greater in the transcranial direct-current stimulation condition. There was no significant change in go processing-times during or after transcranial direct-current stimulation in either condition. Anodal transcranial direct-current stimulation was feasibly coupled to an interactive improvement in inhibitory control. This coupling led to a decrease in the stop-signal process time required for the appropriate responses between motor execution and inhibition. However, there was no transcranial direct-current stimulation effect on the no-signal reaction time during the stop-signal task. Transcranial direct-current stimulation can adjust certain behaviors, and it could be a useful clinical intervention for patients who have difficulties with response inhibition.

  5. Adaptive threshold hunting for the effects of transcranial direct current stimulation on primary motor cortex inhibition.

    Mooney, Ronan A; Cirillo, John; Byblow, Winston D

    2018-06-01

    Primary motor cortex excitability can be modulated by anodal and cathodal transcranial direct current stimulation (tDCS). These neuromodulatory effects may, in part, be dependent on modulation within gamma-aminobutyric acid (GABA)-mediated inhibitory networks. GABAergic function can be quantified non-invasively using adaptive threshold hunting paired-pulse transcranial magnetic stimulation (TMS). The previous studies have used TMS with posterior-anterior (PA) induced current to assess tDCS effects on inhibition. However, TMS with anterior-posterior (AP) induced current in the brain provides a more robust measure of GABA-mediated inhibition. The aim of the present study was to assess the modulation of corticomotor excitability and inhibition after anodal and cathodal tDCS using TMS with PA- and AP-induced current. In 16 young adults (26 ± 1 years), we investigated the response to anodal, cathodal, and sham tDCS in a repeated-measures double-blinded crossover design. Adaptive threshold hunting paired-pulse TMS with PA- and AP-induced current was used to examine separate interneuronal populations within M1 and their influence on corticomotor excitability and short- and long-interval inhibition (SICI and LICI) for up to 60 min after tDCS. Unexpectedly, cathodal tDCS increased corticomotor excitability assessed with AP (P = 0.047) but not PA stimulation (P = 0.74). SICI AP was reduced after anodal tDCS compared with sham (P = 0.040). Pearson's correlations indicated that SICI AP and LICI AP modulation was associated with corticomotor excitability after anodal (P = 0.027) and cathodal tDCS (P = 0.042). The after-effects of tDCS on corticomotor excitability may depend on the direction of the TMS-induced current used to make assessments, and on modulation within GABA-mediated inhibitory circuits.

  6. First direct observations linking confined supercritical turbidity currents to their depositional architecture and facies characteristics

    Hage, S.; Cartigny, M.; Hughes Clarke, J. E.; Clare, M. A.; Sumner, E.; Hubbard, S. M.; Talling, P.; Lintern, G.; Stacey, C.; Vardy, M. E.; Hunt, J.; Vendettuoli, D.; Yokokawa, M.; Hizzett, J. L.; Vellinga, A. J.; Azpiroz, M.

    2017-12-01

    Turbidity currents transfer globally significant amounts of sediment via submarine channels from the continental margin to deep submarine fans. Submarine channel inception is thought to result from erosive, supercritical turbidity currents that are common in proximal settings of the marine realm. Recent monitoring of submarine processes have provided the first measurements of supercritical turbidity currents (Hughes Clarke, 2016), demonstrating that they drive the upstream migration of crescentic bedforms in confined submarine channels. Although upstream-migrating bedforms are common in confined channels across the world's oceans, there is considerable debate over the type of deposits that they produce. It is important to understand what types of deposit record these supercritical bedforms to potentially identify them from geological archives. For the first time, we combine direct measurements from supercritical field-scale turbidity currents with the facies and depositional architecture resulting from such flows. We show how the subsurface architecture evolves in a highly active channel at Squamish submarine delta, British Columbia, Canada. Repeated upstream migration of bedforms is found to create two main deposit geometries. First, regular back-stepping beds result from flow deceleration on the slightly-inclined sides of the bedforms. Second, lens-shaped scour fills composed of massive deposits result from erosion of the back-stepping beds by subsequent turbidity currents. We relate our findings to a range of ancient outcrop studies to demonstrate that supercritical flows are common in proximal settings through the geological record. This study provides the first direct observation-based model to identify confined supercritical turbidity currents and their associated upslope-migrating bedforms in the sedimentary record. This is important for correctly identifying the proximal sites of ancient submarine channels that served as past conduits for globally

  7. Characterizing Ductile Damage and Failure: Application of the Direct Current Potential Drop Method to Uncracked Tensile Specimens

    Brinnel, V.; Döbereiner, B.; Münstermann, Sebastian

    2014-01-01

    Modern high-strength steels exhibit excellent ductility properties but their application is hindered by traditional design rules. A characterization of necessary safety margins for the ductile failure of these steels is therefore required. Direct observation of ductile damage within tests is currently not possible, only limited measurements can be made with synchrotron or X-ray radiation facilities. The direct current potential drop (DCPD) method can determine ductile crack propagation with l...

  8. Effect of Cathodal Transcranial Direct Current Stimulation on a Child with Involuntary Movement after Hypoxic Encephalopathy

    Mayumi Nagai

    2018-01-01

    Full Text Available The aim of the study was to investigate the effect of cathodal transcranial direct current stimulation to the supplementary motor area to inhibit involuntary movements of a child. An 8-year-old boy who developed hypoxic encephalopathy after asphyxia at the age of 2 had difficulty in remaining standing without support because of involuntary movements. He was instructed to remain standing with his plastic ankle-foot orthosis for 10 s at three time points by leaning forward with his forearms on a desk. He received cathodal or sham transcranial direct current stimulation to the supplementary motor area at 1 mA for 10 min. Involuntary movements during standing were measured using an accelerometer attached to his forehead. The low-frequency power of involuntary movements during cathodal transcranial direct current stimulation significantly decreased compared with that during sham stimulation. No adverse effects were observed. Involuntary movement reduction by cathodal stimulation to supplementary motor areas suggests that stimulations modulated the corticobasal ganglia motor circuit. Cathodal stimulation to supplementary motor areas may be effective for reducing involuntary movements and may be safely applied to children with movement disorders.

  9. Variability in measured current structure on the southwest continental shelf of India

    DineshKumar, P.K.; Srinivas, K.

    -1 Variability in Measured Current Structure on the Southwest Continental Shelf of India P.K. Dinesh Kumar and K. Srinivas National Institute of Oceanography, Regional Centre P.O.Box 1913, Cochin - 682018,India Email: dineshku@niokochi.org ABSTRACT... WORDS: Direct current measurements, tidal currents, southwest coast of India. INTRODUCTION The circulation pattern of the eastern Arabian Sea over the southwest continental shelf of India (inferred...

  10. Measurement of the absolute tunneling current density in field emission from tungsten(110)

    Ehrlich, C.D.; Plummer, E.W.

    1978-01-01

    The phenomenon of quantum-mechanical tunneling of an electron through a barrier in the potential energy has been well established in a variety of experiments. The quantity which is usually measured in these experiments is the rate of change of tunneling current and not the absolute current density. This paper reports on a direct measurement of the tunneling current density, which is found to be in good agreement with free-electron theory for W

  11. Direct measurement of VOC diffusivities in tree tissues

    Baduru, K.K.; Trapp, Stefan; Burken, Joel G.

    2008-01-01

    Recent discoveries in the phytoremediation of volatile organic compounds (VOCs) show that vapor-phase transport into roots leads to VOC removal from the vadose zone and diffusion and volatilization out of plants is an important fate following uptake. Volatilization to the atmosphere constitutes one...... in numerous vegetation−VOC interactions, including the phytoremediation of soil vapors and dissolved aqueous-phase contaminants. The diffusion of VOCs through freshly excised tree tissue was directly measured for common groundwater contaminants, chlorinated compounds such as trichloroethylene, perchloroethene......, and tetrachloroethane and aromatic hydrocarbons such as benzene, toluene, and methyl tert-butyl ether. All compounds tested are currently being treated at full scale with tree-based phytoremediation. Diffusivities were determined by modeling the diffusive transport data with a one-dimensional diffusive flux model...

  12. Direct electronic measurement of Peltier cooling and heating in graphene.

    Vera-Marun, I J; van den Berg, J J; Dejene, F K; van Wees, B J

    2016-05-10

    Thermoelectric effects allow the generation of electrical power from waste heat and the electrical control of cooling and heating. Remarkably, these effects are also highly sensitive to the asymmetry in the density of states around the Fermi energy and can therefore be exploited as probes of distortions in the electronic structure at the nanoscale. Here we consider two-dimensional graphene as an excellent nanoscale carbon material for exploring the interaction between electronic and thermal transport phenomena, by presenting a direct and quantitative measurement of the Peltier component to electronic cooling and heating in graphene. Thanks to an architecture including nanoscale thermometers, we detected Peltier component modulation of up to 15 mK for currents of 20 μA at room temperature and observed a full reversal between Peltier cooling and heating for electron and hole regimes. This fundamental thermodynamic property is a complementary tool for the study of nanoscale thermoelectric transport in two-dimensional materials.

  13. Direct methods for radionuclides measurement in water environment

    Chernyaev, A.; Gaponov, I.; Kazennov, A.

    2004-01-01

    The paper is devoted to the direct method of anthropogenic radionuclide measurement in the water environment. Opportunities of application of submersible gamma-spectrometers for in situ underwater measurements of gamma-radiating nuclides and also the direct method for 90 Sr detection are considered

  14. Current measurement studies around the Cesme Peninsula (Turkey)

    Taspinar, N.

    1989-04-01

    In order to design coastal structures and marine vehicles safely, it is required to know current climate which shows the variation of the current characteristics with time. There are a wide variety of current meters designed to measure water flow today. Each current meter is capable of recording the influence of mooring arrangement. Here we describe sea water temperatures, salinities and current velocities at offshore of Akburun, Tatlicak Burnu, Kalem Burnu and Kizil Burun areas in Cesme Peninsula 27 August, 1986 to 19 November, 1986. At the end of the investigations, measured significant maximum and average current velocities have been routinely analysed with micro-computers and also the percentages of current velocity have been calculated. (author). 8 refs, 6 figs, 4 tabs

  15. Onsite-effects of dual-hemisphere versus conventional single-hemisphere transcranial direct current stimulation

    Kwon, Yong Hyun; Jang, Sung Ho

    2012-01-01

    We performed functional MRI examinations in six right-handed healthy subjects. During functional MRI scanning, transcranial direct current stimulation was delivered with the anode over the right primary sensorimotor cortex and the cathode over the left primary sensorimotor cortex using dual-hemispheric transcranial direct current stimulation. This was compared to a cathode over the left supraorbital area using conventional single-hemispheric transcranial direct current stimulation. Voxel coun...

  16. Basic properties of the current-current correlation measure for random Schroedinger operators

    Hislop, Peter D.; Lenoble, Olivier

    2006-01-01

    The current-current correlation measure plays a crucial role in the theory of conductivity for disordered systems. We prove a Pastur-Shubin-type formula for the current-current correlation measure expressing it as a thermodynamic limit for random Schroedinger operators on the lattice and the continuum. We prove that the limit is independent of the self-adjoint boundary conditions and independent of a large family of expanding regions. We relate this finite-volume definition to the definition obtained by using the infinite-volume operators and the trace-per-unit volume

  17. Cathode fall model and current-voltage characteristics of field emission driven direct current microplasmas

    Venkattraman, Ayyaswamy [Department of Applied Mechanics, Indian Institute of Technology Madras, Chennai 600036 (India)

    2013-11-15

    The post-breakdown characteristics of field emission driven microplasma are studied theoretically and numerically. A cathode fall model assuming a linearly varying electric field is used to obtain equations governing the operation of steady state field emission driven microplasmas. The results obtained from the model by solving these equations are compared with particle-in-cell with Monte Carlo collisions simulation results for parameters including the plasma potential, cathode fall thickness, ion number density in the cathode fall, and current density vs voltage curves. The model shows good overall agreement with the simulations but results in slightly overpredicted values for the plasma potential and the cathode fall thickness attributed to the assumed electric field profile. The current density vs voltage curves obtained show an arc region characterized by negative slope as well as an abnormal glow discharge characterized by a positive slope in gaps as small as 10 μm operating at atmospheric pressure. The model also retrieves the traditional macroscale current vs voltage theory in the absence of field emission.

  18. Cathode fall model and current-voltage characteristics of field emission driven direct current microplasmas

    Venkattraman, Ayyaswamy

    2013-01-01

    The post-breakdown characteristics of field emission driven microplasma are studied theoretically and numerically. A cathode fall model assuming a linearly varying electric field is used to obtain equations governing the operation of steady state field emission driven microplasmas. The results obtained from the model by solving these equations are compared with particle-in-cell with Monte Carlo collisions simulation results for parameters including the plasma potential, cathode fall thickness, ion number density in the cathode fall, and current density vs voltage curves. The model shows good overall agreement with the simulations but results in slightly overpredicted values for the plasma potential and the cathode fall thickness attributed to the assumed electric field profile. The current density vs voltage curves obtained show an arc region characterized by negative slope as well as an abnormal glow discharge characterized by a positive slope in gaps as small as 10 μm operating at atmospheric pressure. The model also retrieves the traditional macroscale current vs voltage theory in the absence of field emission

  19. Comparative studies of high-frequency and direct current molecular gas discharges

    Goichman, V.H.; Goldfarb, V.M.; Tendler, M.B.

    1975-01-01

    Electron gas parameters, gas temperatures, ionization and thermal instability are found to be markedly different in direct current glow discharges from capactive electrodless high frequency discharge even when equal net power input is provided. It is reasonable to expect that the combined discharge containing both types of discharges mentioned above may be expected to improve significantly both the steady-state and transient characteristics of the plasma. The characteristics of different discharges in air, nitrogen air-CO 2 -He mixture have been compared. Because of the lack of the direct electrical methods for measurements of the hf plasma, exphasis in this investigation has been laid on both theoretical) based on the analytical expression for electron energy distribution function received previously and experimental spectroscopic evaluations of the plasma parameters. (Auth.)

  20. Low noise constant current source for bias dependent noise measurements

    Talukdar, D.; Bose, Suvendu; Bardhan, K. K.; Chakraborty, R. K.

    2011-01-01

    A low noise constant current source used for measuring the 1/f noise in disordered systems in ohmic as well as nonohmic regime is described. The source can supply low noise constant current starting from as low as 1 μA to a few tens of milliampere with a high voltage compliance limit of around 20 V. The constant current source has several stages, which can work in a standalone manner or together to supply the desired value of load current. The noise contributed by the current source is very low in the entire current range. The fabrication of a low noise voltage preamplifier modified for bias dependent noise measurements and based on the existing design available in the MAT04 data sheet is also described.

  1. Direct current plasma jet at atmospheric pressure operating in nitrogen and air

    Deng, X. L.; Nikiforov, A. Yu.; Vanraes, P.; Leys, Ch.

    2013-01-01

    An atmospheric pressure direct current (DC) plasma jet is investigated in N2 and dry air in terms of plasma properties and generation of active species in the active zone and the afterglow. The influence of working gases and the discharge current on plasma parameters and afterglow properties are studied. The electrical diagnostics show that discharge can be sustained in two different operating modes, depending on the current range: a self-pulsing regime at low current and a glow regime at high current. The gas temperature and the N2 vibrational temperature in the active zone of the jet and in the afterglow are determined by means of emission spectroscopy, based on fitting spectra of N2 second positive system (C3Π-B3Π) and the Boltzmann plot method, respectively. The spectra and temperature differences between the N2 and the air plasma jet are presented and analyzed. Space-resolved ozone and nitric oxide density measurements are carried out in the afterglow of the jet. The density of ozone, which is formed in the afterglow of nitrogen plasma jet, is quantitatively detected by an ozone monitor. The density of nitric oxide, which is generated only in the air plasma jet, is determined by means of mass-spectroscopy techniques.

  2. Measurement of Neutrino Induced, Charged Current, Charged Pion Production

    Wilking, Michael Joseph [Univ. of Colorado, Boulder, CO (United States)

    2009-05-01

    Neutrinos are among the least understood particles in the standard model of particle physics. At neutrino energies in the 1 GeV range, neutrino properties are typically determined by observing the outgoing charged lepton produced in a charged current quasi-elastic interactions. The largest charged current background to these measurements comes from charged current pion production interactions, for which there is very little available data.

  3. Hall probe for measuring high currents in superconducting coils

    Ferendeci, A.M.

    1986-01-01

    Constructional details of a compact Hall probe for measuring high currents in superconducting coils are given. The Hall probe is easy to assemble and can be inserted or removed from the system without breaking the superconducting loop. Upper current limit of the probe can be increased by using larger magnetic core material. Shielding becomes necessary if the probe holder is to be placed near large current dependent magnetic fields

  4. Converter for Measurement of non-sinusoidal current peak value

    Butvin, P.; Nielsen, Otto V; Brauer, Peter

    1997-01-01

    A linear-response toroid with core wound of rapidly quenched soft magnetic metallic ribbon and fitted with two windings is used to enable correct measurement of mean peak value of non-sinusoidal and not noise-free alternating current.......A linear-response toroid with core wound of rapidly quenched soft magnetic metallic ribbon and fitted with two windings is used to enable correct measurement of mean peak value of non-sinusoidal and not noise-free alternating current....

  5. Measurements of current penetration during PDX discharge start-up

    Meyerhofer, D.D.; Goldston, R.J.; Kaita, R.; Cavallo, A.; Grek, B.; Johnson, D.; McCune, D.C.; McGuire, K.; White, R.B.

    1984-11-01

    The current penetration phase of PDX discharges is examined. The Fast Ion Diagnostic Experiment has been used to measure the temporal evolution of the central q (r/a < 0.4), and to show the effect of magnetic perturbations on fast ions. During plasma current penetration, a series of magnetic perturbations was observed in the plasma. If the current was rising rapidly, the perturbations were accompanied by increases in β/sub theta/ + l/sub i//2 and decreases in the loop voltage, suggesting a rapid penetration of the plasma current. When the plasma current was rising slowly, a series of minor disruptions occurred. These were accompanied by decreases in β/sub theta/ + l/sub i//2 and the loop voltage, and increases in the plasma current. During this phase, current penetration may be enhanced by the change in the resistivity profile which accompanies the disruption

  6. History and current safety measures at Laguna Palcacocha, Huaraz, Peru

    Salazar Checa, César; Cochachin, Alejo; Frey, Holger; Huggel, Christian; Portocarrero, César

    2017-04-01

    Laguna Palcacocha is a large glacier lake in the Cordillera Blanca, Peru, located in the Quillcay catchment, above the city of Huaraz, the local capital. On 13 December 1941, the moraine dam lake collapsed, probably after having been impacted by a large ice avalanche, and triggered a major outburst flood. This GLOF destroyed about a third of the city of Huaraz, causing about 2,000 casualties and is therefore one of the deadliest glacier lake outbursts known in history. In 1974, the Glaciology Unit of Peru, responsible for the studying, monitoring and mitigation works related to glacier hazards installed a reinforcement of the natural moraine dam of the newly filled Laguna Palcacocha, with an artificial drainage channel at 7 m below the crest of the reinforced dam. At that time, the lake had an area of 66,800 m2 and a volume of 0.5 x 106 m3. During the past decades, in the course of continued glacier retreat, Laguna Palcacocha has undergone an extreme growth. In February 2016, the lake had an area of 514,000 m2 (7.7 times the area of 1974) and a volume of more than 17 x 106 m3 (more than 34 times the volume of 1974). At the same time, the city of Huaraz, located 20 km downstream of the lake, grew significantly after its almost complete destruction by the 1970 earthquake. Today, about 120,000 people are living in the city. Due to the persisting possibility for large ice avalanches directly above the Palcacocha lake, this constitutes a high-risk situation, requiring new hazard and risk mitigation measures. As an immediate temporal measure, in order to bridge the time until the realization of a more permanent measure, a syphoning system has been installed in 2011, using about ten 700-m pipes with a 10-inch (25.4 cm) diameter. The aim of this syphoning attempt is to lower the lake level by about 7 m, and therefore reduce the lake volume on the one hand, and also reach a higher dam freeboard. However, the system is less effective than assumed, currently the lake level

  7. Bending Under Tension Test with Direct Friction Measurement

    Andreasen, Jan Lasson; Olsson, David Dam; Chodnikiewicz, K.

    2006-01-01

    A special Bending-Under-Tension (BUT) transducer has been developed in which friction around the tool radius can be directly measured when drawing a plane sheet strip around a cylindrical tool-pin under constant back tension. The front tension, back tension and torque on the tool-pin are all...... measured directly, thus enabling accurate measurement of friction and direct determination of lubricant film breakdown for varying normal pressure, sliding speed, tool radius and tool preheat temperature. The transducer is applied in an experimental investigation focusing on limits of lubrication...

  8. Bending Under Tension Test with Direct Friction Measurement

    Andreasen, Jan Lasson; Olsson, David Dam; Chodnikiewicz, K.

    2004-01-01

    A special BUT-transducer has been developed in which friction around the tool radius can be directly measured when drawing a plane sheet strip around a cylindrical tool-pin under constant back tension. The front tension, back tension and torque on the tool-pin are all measured directly, thus...... enabling accurate measurement of friction and direct determination of lubricant film breakdown for varying normal pressure, sliding speed, tool radius and tool preheat temperature. The transducer is applied in an experimental investigation focusing on limits of lubrication in drawing of stainless steel...

  9. Subcortical structures in humans can be facilitated by transcranial direct current stimulation

    Nonnekes, Johan Hendrik; Arrogi, Anass; Munneke, Moniek; van Asseldonk, Edwin H.F.; Oude Nijhuis, Lars; Geurts, Alexander; Weerdesteyn, Vivian

    2014-01-01

    BACKGROUND: Transcranial direct current stimulation (tDCS) is a noninvasive brain stimulation technique that alters cortical excitability via application of a weak direct current. Interestingly, it was demonstrated in cats that tDCS can facilitate subcortical structures as well (Bolzonii et al., J

  10. Direct current magnetron sputtering deposition of InN thin films

    Cai Xingmin; Hao Yanqing; Zhang Dongping; Fan Ping

    2009-01-01

    In this paper, InN thin films were deposited on Si (1 0 0) and K9 glass by reactive direct current magnetron sputtering. The target was In metal with the purity of 99.999% and the gases were Ar (99.999%) and N 2 (99.999%). The properties of InN thin films were studied. Scanning electron microscopy (SEM) shows that the film surface is very rough and energy dispersive X-ray spectroscopy (EDX) shows that the film contains In, N and very little O. X-ray diffraction (XRD) and Raman scattering reveal that the film mainly contains hexagonal InN. The four-probe measurement shows that InN film is conductive. The transmission measurement demonstrates that the transmission of InN deposited on K9 glass is as low as 0.5% from 400 nm to 800 nm.

  11. Development of an external Faraday cup for beam current measurements

    Kim, Kye-Ryung; Jung, Myung-Hwan; Ra, Se-Jin; Lee, Seok-Ki

    2010-01-01

    In general, beam current measurements are very important for many kinds of experiments using highly energetic particle beams at accelerators, such as cyclotrons, linacs, etc. The Faraday cup is known to be one of the most popular beam current measurement tools. We developed an external Faraday cup to measure the beam current at a dedicated beam line for low-flux experiments installed at the MC-50 cyclotron of Korea Institute of Radiological and Medical Sciences (KIRAMS). It was designed for external beam current measurements and is composed of a vacuum chamber, an entrance window, a collimator, a electrostatic suppressor ring, and a cup. The window is made of 75-um-thick Kapton film, and the diameter of the collimator is 10 mm or 20 mm. The ring and the cup has 5-cm inner diameters, and the thickness of the bottom of the cup is 2 cm, which is enough to absorb the total proton energy up to 45 MeV. Using this external Faraday cup, we measured the beam current from the cyclotron, and we compared measured flux to the results from film dosimetry using GAF films.

  12. Resistance and sheet resistance measurements using electron beam induced current

    Czerwinski, A.; Pluska, M.; Ratajczak, J.; Szerling, A.; KaPtcki, J.

    2006-01-01

    A method for measurement of spatially uniform or nonuniform resistance in layers and strips, based on electron beam induced current (EBIC) technique, is described. High electron beam currents are used so that the overall resistance of the measurement circuit affects the EBIC signal. During the evaluation, the electron beam is scanned along the measured object, whose load resistance varies with the distance. The variation is compensated by an adjustable resistance within an external circuit. The method has been experimentally deployed for sheet resistance determination of buried regions of lateral confinements in semiconductor laser heterostructures manufactured by molecular beam epitaxy

  13. Measurement in Marketing: Current Scenario, Recommendations and Challenges

    Felipe Zambaldi

    2014-05-01

    Full Text Available The purpose of this article is to discuss about construct measurement in Marketing by summarizing the main considerations about the subject. First, it discusses the origins of the debates about the theme since the 1970s and describes its main consolidated models (the classical Churchill’s model, the COARSE model and the formative measurement model. Then it presents current concerns about the classical approach with relevant recommendations (particularly regarding multi-item measurement, single-item measurement, rating scales and cross-cultural aspects. At the end, it presents considerations about measurement trends in Marketing with emphasis on the Item Response Theory (IRT, Bayesian estimators and Partial Least Squares (PLS. The article updates the debate on the theme and contributes to Marketing experts and researchers who demand a current view about measurement and recommendations for research development. 

  14. Accurate measurement of directional emittance of solar energy materials

    Nijnatten, van P.A.; Hugo-Le Gof, A.; Granqvist, C.-G.; Lampert, C.M.

    1992-01-01

    Directional emittance plays an important role in the calculation of radiative heat exchange. It partly determines the thermal insulation of single and multiple glazing and the efficiency of solar collectors. An emissiometer has been designed and built, capable for measurements of the directional

  15. First current density measurements in the ring current region using simultaneous multi-spacecraft CLUSTER-FGM data

    C. Vallat

    2005-07-01

    Full Text Available The inner magnetosphere's current mapping is one of the key elements for current loop closure inside the entire magnetosphere. A method for directly computing the current is the multi-spacecraft curlometer technique, which is based on the application of Maxwell-Ampère's law. This requires the use of four-point magnetic field high resolution measurements. The FGM experiment on board the four Cluster spacecraft allows, for the first time, an instantaneous calculation of the magnetic field gradients and thus a measurement of the local current density. This technique requires, however, a careful study concerning all the factors that can affect the accuracy of the J estimate, such as the tetrahedral geometry of the four spacecraft, or the size and orientation of the current structure sampled. The first part of this paper is thus providing a detailed analysis of the method accuracy, and points out the limitations of this technique in the region of interest. The second part is an analysis of the ring current region, which reveals, for the first time, the large latitudinal extent of the ring current, for all magnetic activity levels, as well as the latitudinal evolution of the perpendicular (and parallel components of the current along the diffuse auroral zone. Our analysis also points out the sharp transition between two distinct plasma regions, with the existence of high diamagnetic currents at the interface, as well as the filamentation of the current inside the inner plasma sheet. A statistical study over multiple perigee passes of Cluster (at about 4 RE from the Earth reveals the azimuthal extent of the partial ring current. It also reveals that, at these distances and all along the evening sector, there isn't necessarily a strong dependence of the local current density value on the magnetic activity level. This is a direct consequence of the ring current morphology evolution, as well as the relative

  16. 3-D direct current resistivity anisotropic modelling by goal-oriented adaptive finite element methods

    Ren, Zhengyong; Qiu, Lewen; Tang, Jingtian; Wu, Xiaoping; Xiao, Xiao; Zhou, Zilong

    2018-01-01

    Although accurate numerical solvers for 3-D direct current (DC) isotropic resistivity models are current available even for complicated models with topography, reliable numerical solvers for the anisotropic case are still an open question. This study aims to develop a novel and optimal numerical solver for accurately calculating the DC potentials for complicated models with arbitrary anisotropic conductivity structures in the Earth. First, a secondary potential boundary value problem is derived by considering the topography and the anisotropic conductivity. Then, two a posteriori error estimators with one using the gradient-recovery technique and one measuring the discontinuity of the normal component of current density are developed for the anisotropic cases. Combing the goal-oriented and non-goal-oriented mesh refinements and these two error estimators, four different solving strategies are developed for complicated DC anisotropic forward modelling problems. A synthetic anisotropic two-layer model with analytic solutions verified the accuracy of our algorithms. A half-space model with a buried anisotropic cube and a mountain-valley model are adopted to test the convergence rates of these four solving strategies. We found that the error estimator based on the discontinuity of current density shows better performance than the gradient-recovery based a posteriori error estimator for anisotropic models with conductivity contrasts. Both error estimators working together with goal-oriented concepts can offer optimal mesh density distributions and highly accurate solutions.

  17. Online effects of transcranial direct current stimulation on prefrontal metabolites in gambling disorder.

    Dickler, Maya; Lenglos, Christophe; Renauld, Emmanuelle; Ferland, Francine; Edden, Richard A; Leblond, Jean; Fecteau, Shirley

    2018-03-15

    Gambling disorder is characterized by persistent maladaptive gambling behaviors and is now considered among substance-related and addictive disorders. There is still unmet therapeutic need for these clinical populations, however recent advances indicate that interventions targeting the Glutamatergic/GABAergic system hold promise in reducing symptoms in substance-related and addictive disorders, including gambling disorder. There is some data indicating that transcranial direct current stimulation may hold clinical benefits in substance use disorders and modulate levels of brain metabolites including glutamate and GABA. The goal of the present work was to test whether this non-invasive neurostimulation method modulates key metabolites in gambling disorder. We conducted a sham-controlled, crossover, randomized study, blinded at two levels in order to characterize the effects of transcranial direct current stimulation over the dorsolateral prefrontal cortex on neural metabolites levels in sixteen patients with gambling disorder. Metabolite levels were measured with magnetic resonance spectroscopy from the right dorsolateral prefrontal cortex and the right striatum during active and sham stimulation. Active as compared to sham stimulation elevated prefrontal GABA levels. There were no significant changes between stimulation conditions in prefrontal glutamate + glutamine and N-acetyl Aspartate, or in striatal metabolite levels. Results also indicated positive correlations between metabolite levels during active, but not sham, stimulation and levels of risk taking, impulsivity and craving. Our findings suggest that transcranial direct current stimulation can modulate GABA levels in patients with gambling disorder which may represent an interesting future therapeutic avenue. Copyright © 2017 Elsevier Ltd. All rights reserved.

  18. On the structure of intermediate state created by the direct current

    Kan, Ya.S.; Frolov, V.A.

    1974-01-01

    Observations were made of the structure of an intermediate state formed at the destruction of superconductivity of a cylindrical tin sample by an electric current through it. For this purpose, there was determined the nature of the dependence of the magnetic permeability averaged over a section normal with the sample axis on the position of this section relative to the axis. the quantity actually measured was the inductance of a short (0.5 mm) superconductive probe coil embracing the sample and moving along the axis of the latter. In order the inductance were representatative of the magnetic permeability in the depth of a thick (5 mm in diameter) sample, measurements were made with a direct current by means of the device specially designed for this purpose; the operating principle and method for checking of this device being briefly described in the paper. The curves of oscillations of the inductance of the probe with the latter being moved along the sample suggested a conclusion that the structure of the intermediate state had a periodic nature (of the London type) with a period of 1.3 mm. The reduction of the oscillation amplitude and the increase of their average level while an increase of the current passing through the sample above the critical value (at constant temperature) indicated the reduction of the diameter of the core, being in the intermediate state, and an increase of the thickness of a normal layer. Measurements were made at temperatures (13-17)x10 -3 deg K below Tsub(k) with a current of 2-3 A in the sample

  19. Plasma flow measurement using directional Langmuir probe under weakly ion-magnetized conditions

    Nagaoka, Kenichi; Okamoto, Atsushi [Graduate School of Science, Nagoya Univ., Nagoya (Japan); Yoshimura, Shinji; Tanaka, Masayoshi Y. [National Inst. for Fusion Science, Toki, Gifu (Japan)

    2000-07-01

    It is both experimentally and theoretically demonstrated that ion flow velocity at an arbitrary angle with respect to the magnetic field can be measured with a directional Langmuir probe. Based on the symmetry argument, we show that the effect of magnetic field on directional probe current is exactly canceled in determining the ion flow velocity, and obtain the generalized relation between flow velocity and directional probe currents valid for any flowing direction. The absolute value of the flow velocity is determined by an in situ calibration method of the probe. The applicability limit of the present method to a strongly ion-magnetized plasma is experimentally examined. (author)

  20. Current Measurements and Overwash Monitoring Using Tilt Current Meters in Three Coastal Environments

    Lowell, N. S.; Sherwood, C. R.; Decarlo, T. M.; Grant, J. R.

    2014-12-01

    Tilt Current Meters (TCMs) provide accurate, cost effective measurements of near-bottom current velocities. Many studies in coastal environments require current measurements, which are frequently made with Acoustic Doppler Profilers (ADPs). ADPs are expensive, however, and may not be suitable for locations where there is significant risk of damage, loss, or theft or where a large spatial array of measurements is required. TCMs, by contrast, are smaller, less expensive, and easier to deploy. This study tested TCMs in three sites to determine their suitability for use in research applications. TCMs are based on the drag-tilt principle, where the instrument tilts in response to current. The meter consists of a buoyant float with an onboard accelerometer, three-axis tilt sensor, three-axis magnetometer (compass), and a data logger. Current measurements are derived by post processing the tilt and compass values and converting them to velocity using empirical calibration data. Large data-storage capacity (4 GB) and low power requirements allow long deployments (many months) at high sample rates (16 Hz). We demonstrate the utility of TCM current measurements on a reef at Dongsha Atoll in the South China Sea, and in Vineyard Sound off Cape Cod, where the TCM performance was evaluated against ADP measurements. We have also used the TCM to record waves during an overwash event on a Cape Cod barrier beach during a winter storm. The TCM recorded waves as they came through the overwash channel, and the data were in agreement with the water-level record used as a reference. These tests demonstrate that TCMs may be used in a variety of near shore environments and have the potential to significantly increase the density of meters in future studies were current measurements are required.

  1. Induced electric currents in the Alaska oil pipeline measured by gradient, fluxgate, and SQUID magnetometers

    Campbell, W. H.; Zimmerman, J. E.

    1979-01-01

    The field gradient method for observing the electric currents in the Alaska pipeline provided consistent values for both the fluxgate and SQUID method of observation. These currents were linearly related to the regularly measured electric and magnetic field changes. Determinations of pipeline current were consistent with values obtained by a direct connection, current shunt technique at a pipeline site about 9.6 km away. The gradient method has the distinct advantage of portability and buried- pipe capability. Field gradients due to the pipe magnetization, geological features, or ionospheric source currents do not seem to contribute a measurable error to such pipe current determination. The SQUID gradiometer is inherently sensitive enough to detect very small currents in a linear conductor at 10 meters, or conversely, to detect small currents of one amphere or more at relatively great distances. It is fairly straightforward to achieve imbalance less than one part in ten thousand, and with extreme care, one part in one million or better.

  2. Hybrid Direct Carbon Fuel Cell Performance with Anode Current Collector Material

    Deleebeeck, Lisa; Kammer Hansen, Kent

    2015-01-01

    collectors were studied: Au, Ni, Ag, and Pt. It was shown that the performance of the direct carbon fuel cell (DCFC) is dependent on the current collector materials, Ni and Pt giving the best performance, due to their catalytic activity. Gold is suggested to be the best material as an inert current collector......The influence of the current collector on the performance of a hybrid direct carbon fuel cell (HDCFC), consisting of solid oxide fuel cell (SOFC) with a molten carbonate-carbon slurry in contact with the anode, has been investigated using current-voltage curves. Four different anode current...

  3. Direct measurement of γ-emitting radionuclides in waste drum

    Ma Ruwei; Mao Yong; Zhang Xiuzhen; Xia Xiaobin; Guo Caiping; Han Yueqin

    1993-01-01

    The low-level rad waste produced from nuclear power plant, nuclear facilities, and in the process of their decommissioning is stored in waste depository. For the safety of transport and storage of these wastes, some test must be done. One of them is to analyse the kinds and activities of radionuclides in each waste drum. Segmented scanning gamma spectrum analysis can be used for direct measurement of gamma-emitting radionuclides in drum. Gamma emitters such as Co-60, Cs-137, Ra-226 can be measured directly from outside of drum. A method and system for direct measuring gamma emitters in waste drum are described, and measuring apparatus and measurement results as well

  4. Image analysis software versus direct anthropometry for breast measurements.

    Quieregatto, Paulo Rogério; Hochman, Bernardo; Furtado, Fabianne; Machado, Aline Fernanda Perez; Sabino Neto, Miguel; Ferreira, Lydia Masako

    2014-10-01

    To compare breast measurements performed using the software packages ImageTool(r), AutoCAD(r) and Adobe Photoshop(r) with direct anthropometric measurements. Points were marked on the breasts and arms of 40 volunteer women aged between 18 and 60 years. When connecting the points, seven linear segments and one angular measurement on each half of the body, and one medial segment common to both body halves were defined. The volunteers were photographed in a standardized manner. Photogrammetric measurements were performed by three independent observers using the three software packages and compared to direct anthropometric measurements made with calipers and a protractor. Measurements obtained with AutoCAD(r) were the most reproducible and those made with ImageTool(r) were the most similar to direct anthropometry, while measurements with Adobe Photoshop(r) showed the largest differences. Except for angular measurements, significant differences were found between measurements of line segments made using the three software packages and those obtained by direct anthropometry. AutoCAD(r) provided the highest precision and intermediate accuracy; ImageTool(r) had the highest accuracy and lowest precision; and Adobe Photoshop(r) showed intermediate precision and the worst accuracy among the three software packages.

  5. A measurement of perpendicular current density in an aurora

    Bering, E.A.; Mozer, F.S.

    1975-01-01

    A Nike Tomahawk sounding rocket was launched into a 400-γ auroral substorm on February 7, 1972, from Esrange, Kiruna, Sweden. The rocket instrumentation included a split Langmuir probe plasma velocity detector and a double-probe electric field detector. Above 140-km altitude the electric field deduced from the ion flow velocity measurement and the electric field measured by the double probe agree to an accuracy within the uncertainties of the two measurements. The difference between the two measurements at altitudes below 140 km provides an in situ measurement of current density and conductivity. Alternatively, if values for the conductivity are assumed, the neutral wind velocity can be deduced. The height-integrated current was 0.11 A/m flowing at an azimuth of 276degree. The neutral winds were strong, exhibited substantial altitude variation in the east-west component, and were predominantly southward

  6. Current measurements by Faraday rotation in single mode optical fibers

    Chandler, G.I.; Jahoda, F.C.

    1984-01-01

    Development of techniques for measuring magnetic fields and currents by Faraday rotation in single-mode optical fibers has continued. We summarize the results of attempts to measure the toroidal plasma current in the ZT-40 Reversed-Field-Pinch using multi-turn fiber coils. The fiber response is reproducible and in accord with theory, but the amount and distribution of the stress-induced birefringence in this case are such that prediction of the sensor response at low currents is difficult if not impossible. The low-current difficulty can be overcome by twisting the fiber to induce a circular birefringence bias. We report the results of auxiliary experiments with a fiber that has been twisted with 15 turns per meter and then re-coated to lock the twist in place

  7. Automatic control system for measuring currents produced by ionization chambers

    Brancaccio, Franco

    2002-01-01

    Ionization Chambers in current mode operation are usually used in Nuclear Metrology. Activity measurements are quickly performed by Ionization Chambers, with very good precision. For this purpose measurements of very low ionization currents, carried out by high quality instrumentation, are required. Usually, electrometers perform the current integration method under command of signals from an automation system, in order to reduce the measurement uncertainties. Among the measurement systems at the Laboratorio de Metrologia Nuclear (LMN) of IPEN, there are two ionization chamber systems. In the present work, an automation system developed for current integration measurements is described. This automation system is composed by software (graphic interface and control) and an electronic module connected to a microcomputer, by means of a commercial data acquisition card. Several test measurements were performed in order to determine the intrinsic uncertainty, linearity and stability of the system. Using calibrated radioactive solutions, the IG12/A20 chamber calibration factors for 18 F and 153 Sm were obtained, making possible to determine activities of these radionuclides. (author)

  8. Proton current measurements using the prompt gamma ray diagnostic technique

    Leeper, R.J.; Burns, E.J.T.; Johnson, D.J.; McMurtry, W.M.

    1981-01-01

    Prompt gamma ray signals from the nuclear reaction 7 Li(p,γ) 8 Be have been used to make time resolved proton current measurements. In these measurements, the proton beam was allowed to strike cylindrical thick lithium metal targets. The time integrated proton current was measured using gamma activation of copper via the reaction 63 Cu(γ,n) 62 Cu(β+). The positron activity of the copper sample was easily measured using coincidence counting techniques. The number of 62 Cu atoms produced per proton incident on a thick Li metal target was determined with separate calibration runs performed on the Sandia 2.5 MeV Van de Graaff accelerator. The time history of the prompt gamma production was measured using six EGG NPM-54 scintillator photomultiplier combinations shielded by 96.5 cm of concrete and 5.1 cm of Pb. The use of six scintillator photomultiplier combinations was necessary to increase the statistical precision of the data. The normalization of the prompt gamma time history data with the total time integrated proton-current measurement yielded the absolute time resolved proton current on target. Data from runs performed on the Sandia Proto I accelerator will be presented

  9. Measurements of the reverse current of highly irradiated silicon sensors to determine the effective energy and current related damage rate

    Wiehe, Moritz; Wonsak, S.; Kuehn, S.; Parzefall, U.; Casse, G.

    2018-01-01

    The reverse current of irradiated silicon sensors leads to self heating of the sensor and degrades the signal to noise ratio of a detector. Precise knowledge of the expected reverse current during detector operation is crucial for planning and running experiments in High Energy Physics. The dependence of the reverse current on sensor temperature and irradiation fluence is parametrized by the effective energy and the current related damage rate, respectively. In this study 18 n-in-p mini silicon strip sensors from companies Hamamatsu Photonics and Micron Semiconductor Ltd. were deployed. Measurements of the reverse current for different bias voltages were performed at temperatures of -32 ° C, -27 ° C and -23 ° C. The sensors were irradiated with reactor neutrons in Ljubljana to fluences ranging from 2 × 1014neq /cm2 to 2 × 1016neq /cm2. The measurements were performed directly after irradiation and after 10 and 30 days of room temperature annealing. The aim of the study presented in this paper is to investigate the reverse current of silicon sensors for high fluences of up to 2 × 1016neq /cm2 and compare the measurements to the parametrization models.

  10. Enhanced motor learning following task-concurrent dual transcranial direct current stimulation.

    Sophia Karok

    Full Text Available OBJECTIVE: Transcranial direct current stimulation (tDCS of the primary motor cortex (M1 has beneficial effects on motor performance and motor learning in healthy subjects and is emerging as a promising tool for motor neurorehabilitation. Applying tDCS concurrently with a motor task has recently been found to be more effective than applying stimulation before the motor task. This study extends this finding to examine whether such task-concurrent stimulation further enhances motor learning on a dual M1 montage. METHOD: Twenty healthy, right-handed subjects received anodal tDCS to the right M1, dual tDCS (anodal current over right M1 and cathodal over left M1 and sham tDCS in a repeated-measures design. Stimulation was applied for 10 mins at 1.5 mA during an explicit motor learning task. Response times (RT and accuracy were measured at baseline, during, directly after and 15 mins after stimulation. Motor cortical excitability was recorded from both hemispheres before and after stimulation using single-pulse transcranial magnetic stimulation. RESULTS: Task-concurrent stimulation with a dual M1 montage significantly reduced RTs by 23% as early as with the onset of stimulation (p<0.01 with this effect increasing to 30% at the final measurement. Polarity-specific changes in cortical excitability were observed with MEPs significantly reduced by 12% in the left M1 and increased by 69% in the right M1. CONCLUSION: Performance improvement occurred earliest in the dual M1 condition with a stable and lasting effect. Unilateral anodal stimulation resulted only in trendwise improvement when compared to sham. Therefore, task-concurrent dual M1 stimulation is most suited for obtaining the desired neuromodulatory effects of tDCS in explicit motor learning.

  11. Transcranial direct current stimulation for motor recovery of upper limb function after stroke.

    Lüdemann-Podubecká, Jitka; Bösl, Kathrin; Rothhardt, Sandra; Verheyden, Geert; Nowak, Dennis Alexander

    2014-11-01

    Changes in neural processing after stroke have been postulated to impede recovery from stroke. Transcranial direct current stimulation has the potential to alter cortico-spinal excitability and thereby might be beneficial in stroke recovery. We review the pertinent literature prior to 30/09/2013 on transcranial direct current stimulation in promoting motor recovery of the affected upper limb after stroke. We found overall 23 trials (they included 523 participants). All stimulation protocols pride on interhemispheric imbalance model. In a comparative approach, methodology and effectiveness of (a) facilitation of the affected hemisphere, (b) inhibition of the unaffected hemisphere and (c) combined application of transcranial direct current stimulation over the affected and unaffected hemispheres to treat impaired hand function after stroke are presented. Transcranial direct current stimulation is associated with improvement of the affected upper limb after stroke, but current evidence does not support its routine use. Copyright © 2014 Elsevier Ltd. All rights reserved.

  12. Effects of transcranial direct current stimulation on motor learning in healthy individuals: a systematic review

    Águida Foerster

    Full Text Available Introduction Transcranial direct current stimulation (tDCS has been used to modify cortical excitability and promote motor learning. Objective To systematically review published data to investigate the effects of transcranial direct current stimulation on motor learning in healthy individuals. Methods Randomized or quasi-randomized studies that evaluated the tDCS effects on motor learning were included and the risk of bias was examined by Cochrane Collaboration’s tool. The following electronic databases were used: PubMed, Scopus, Web of Science, LILACS, CINAHL with no language restriction. Results It was found 160 studies; after reading the title and abstract, 17 of those were selected, but just 4 were included. All studies involved healthy, right-handed adults. All studies assessed motor learning by the Jebsen Taylor Test or by the Serial Finger Tapping Task (SFTT. Almost all studies were randomized and all were blinding for participants. Some studies presented differences at SFTT protocol. Conclusion The result is insufficient to draw conclusions if tDCS influences the motor learning. Furthermore, there was significant heterogeneity of the stimulation parameters used. Further researches are needed to investigate the parameters that are more important for motor learning improvement and measure whether the effects are long-lasting or limited in time.

  13. Direct current stimulation of the left temporoparietal junction modulates dynamic humor appreciation.

    Slaby, Isabella; Holmes, Amanda; Moran, Joseph M; Eddy, Marianna D; Mahoney, Caroline R; Taylor, Holly A; Brunyé, Tad T

    2015-11-11

    The aim of this study was to evaluate the influence of transcranial direct current stimulation targeting the left temporoparietal junction (TPJ) on humor appreciation during a dynamic video rating task. In a within-participants design, we targeted the left TPJ with anodal, cathodal, or no transcranial direct current stimulation, centered at electrode site C3 using a 4×1 targeted stimulation montage. During stimulation, participants dynamically rated a series of six stand-up comedy videos for perceived humor. We measured event-related (time-locked to crowd laughter) modulation of humor ratings as a function of stimulation condition. Results showed decreases in rated humor during anodal (vs. cathodal or none) stimulation; this pattern was evident for the majority of videos and was only partially predicted by individual differences in humor style. We discuss the possibility that upregulation of neural circuits involved in the theory of mind and empathizing with others may reduce appreciation of aggressive humor. In conclusion, the present data show that neuromodulation of the TPJ can alter the mental processes underlying humor appreciation, suggesting critical involvement of this cortical region in detecting, comprehending, and appreciating humor.

  14. Augmentation of Fear Extinction by Transcranial Direct Current Stimulation (tDCS

    Natalie Dittert

    2018-04-01

    Full Text Available Although posttraumatic stress disorder (PTSD; DSM-V 309.82 and anxiety disorders (DSM-V 300.xx are widely spread mental disorders, the effectiveness of their therapy is still unsatisfying. Non-invasive brain-stimulation techniques like transcranial direct current stimulation (tDCS might be an option to improve extinction learning, which is a main functional factor of exposure-based therapy for anxiety disorders. To examine this hypothesis, we used a fear conditioning paradigm with female faces as conditioned stimuli (CS and a 95-dB female scream as unconditioned stimulus (UCS. We aimed to perform a tDCS of the ventromedial prefrontal cortex (vmPFC, which is mainly involved in the control of extinction-processes. Therefore, we applied two 4 × 4 cm electrodes approximately at the EEG-positions F7 and F8 and used a direct current of 1.5 mA. The 20-min stimulation was started during a 10-min break between acquisition and extinction and went on overall extinction-trials. The healthy participants were randomly assigned in two double-blinded process into two sham stimulation and two verum stimulation groups with opposite current flow directions. To measure the fear reactions, we used skin conductance responses (SCR and subjective ratings. We performed a generalized estimating equations model for the SCR to assess the impact of tDCS and current flow direction on extinction processes for all subjects that showed a successful conditioning (N = 84. The results indicate that tDCS accelerates early extinction processes with a significantly faster loss of CS+/CS– discrimination. The discrimination loss was driven by a significant decrease in reaction toward the CS+ as well as an increase in reaction toward the CS– in the tDCS verum groups, whereas the sham groups showed no significant reaction changes during this period. Therefore, we assume that tDCS of the vmPFC can be used to enhance early extinction processes successfully. But before it should be

  15. Measurement of fast risetime megampere currents by quartz gauge

    Williams, R.R.; McDaniel, D.H.; Stinnett, R.W.

    1980-01-01

    Quartz gauges have been used on the Sandia National Laboratories Proto II accelerator to measure current in the magnetically insulated transmission line at the 11 TW power level. The accelerator delivers 3.5 MA at 2 x 10 14 A/s in a 40 ns pulse to a 0.0127 m diameter aluminum liner to produce a high density plasma. At this radius and dI/dt levels, the B-dot monitors no longer function for the measurement of load current because the monitor suffers electrical breakdown. Quartz pressure gauges mounted at a radius of 0.0086 m have successfully measured the magnetic pressure due to the load current with nanosecond temporal resolution

  16. Stimulating thought: a functional MRI study of transcranial direct current stimulation in schizophrenia.

    Orlov, Natasza D; O'Daly, Owen; Tracy, Derek K; Daniju, Yusuf; Hodsoll, John; Valdearenas, Lorena; Rothwell, John; Shergill, Sukhi S

    2017-09-01

    Individuals with schizophrenia typically suffer a range of cognitive deficits, including prominent deficits in working memory and executive function. These difficulties are strongly predictive of functional outcomes, but there is a paucity of effective therapeutic interventions targeting these deficits. Transcranial direct current stimulation is a novel neuromodulatory technique with emerging evidence of potential pro-cognitive effects; however, there is limited understanding of its mechanism. This was a double-blind randomized sham controlled pilot study of transcranial direct current stimulation on a working memory (n-back) and executive function (Stroop) task in 28 individuals with schizophrenia using functional magnetic resonance imaging. Study participants received 30 min of real or sham transcranial direct current stimulation applied to the left frontal cortex. The 'real' and 'sham' groups did not differ in online working memory task performance, but the transcranial direct current stimulation group demonstrated significant improvement in performance at 24 h post-transcranial direct current stimulation. Transcranial direct current stimulation was associated with increased activation in the medial frontal cortex beneath the anode; showing a positive correlation with consolidated working memory performance 24 h post-stimulation. There was reduced activation in the left cerebellum in the transcranial direct current stimulation group, with no change in the middle frontal gyrus or parietal cortices. Improved performance on the executive function task was associated with reduced activity in the anterior cingulate cortex. Transcranial direct current stimulation modulated functional activation in local task-related regions, and in more distal nodes in the network. Transcranial direct current stimulation offers a potential novel approach to altering frontal cortical activity and exerting pro-cognitive effects in schizophrenia. © The Author (2017). Published by Oxford

  17. The morphological and molecular changes of brain cells exposed to direct current electric field stimulation.

    Pelletier, Simon J; Lagacé, Marie; St-Amour, Isabelle; Arsenault, Dany; Cisbani, Giulia; Chabrat, Audrey; Fecteau, Shirley; Lévesque, Martin; Cicchetti, Francesca

    2014-12-07

    The application of low-intensity direct current electric fields has been experimentally used in the clinic to treat a number of brain disorders, predominantly using transcranial direct current stimulation approaches. However, the cellular and molecular changes induced by such treatment remain largely unknown. Here, we tested various intensities of direct current electric fields (0, 25, 50, and 100V/m) in a well-controlled in vitro environment in order to investigate the responses of neurons, microglia, and astrocytes to this type of stimulation. This included morphological assessments of the cells, viability, as well as shape and fiber outgrowth relative to the orientation of the direct current electric field. We also undertook enzyme-linked immunosorbent assays and western immunoblotting to identify which molecular pathways were affected by direct current electric fields. In response to direct current electric field, neurons developed an elongated cell body shape with neurite outgrowth that was associated with a significant increase in growth associated protein-43. Fetal midbrain dopaminergic explants grown in a collagen gel matrix also showed a reorientation of their neurites towards the cathode. BV2 microglial cells adopted distinct morphological changes with an increase in cyclooxygenase-2 expression, but these were dependent on whether they had already been activated with lipopolysaccharide. Finally, astrocytes displayed elongated cell bodies with cellular filopodia that were oriented perpendicularly to the direct current electric field. We show that cells of the central nervous system can respond to direct current electric fields both in terms of their morphological shape and molecular expression of certain proteins, and this in turn can help us to begin understand the mechanisms underlying the clinical benefits of direct current electric field. © The Author 2015. Published by Oxford University Press on behalf of CINP.

  18. Simulation of vibration-induced effect on plasma current measurement using a fiber optic current sensor.

    Descamps, Frédéric; Aerssens, Matthieu; Gusarov, Andrei; Mégret, Patrice; Massaut, Vincent; Wuilpart, Marc

    2014-06-16

    An accurate measurement of the plasma current is of paramount importance for controlling the plasma magnetic equilibrium in tokamaks. Fiber optic current sensor (FOCS) technology is expected to be implemented to perform this task in ITER. However, during ITER operation, the vessel and the sensing fiber will be subject to vibrations and thus to time-dependent parasitic birefringence, which may significantly compromise the FOCS performance. In this paper we investigate the effects of vibrations on the plasma current measurement accuracy under ITER-relevant conditions. The simulation results show that in the case of a FOCS reflection scheme including a spun fiber and a Faraday mirror, the error induced by the vibrations is acceptable regarding the ITER current diagnostics requirements.

  19. Current Consumption Measurements with a Carrier Aggregation Smartphone

    Sanchez-Mejias, Rafael; Guo, Yu; Lauridsen, Mads

    2014-01-01

    on this topic. Currently there are only theoretical expansions of LTE release 8 power models available, but this article presents the first publicly available current consumption measurements on a commercial CA-capable UE. In this work it is examined how the activation and use of CA (10 + 10 MHz) affects the UE......Carrier Aggregation (CA) is introduced in LTE release 10 to improve data rates by allowing the User Equipment (UE) to receive data on more than one LTE carrier. The related increased complexity is expected to affect the UE current consumption, but yet no empirical evaluation has been published...

  20. Measuring electric conductivity in liquid metals by eddy current method

    Zhuravlev, S.P.; Ostrovskij, O.I.; Grigoryan, V.A.

    1982-01-01

    Technique permitting to apply the method of vertiginous currents for investigation of electric conductivity of metal melts in the high temperature range is presented. Interferences affecting accuracy of measurements are specified and ways of their removing are pointed out. Scheme of measuring and design of the facility are described. Results of measuring electric resistance of liquid Fe, Co, Ni obtained for the first time by this method are presented. The data obtained agree with the results of measurements conducted by the method of the rotating magnetic field. Difference in absolute values of electric resistance in parallel experiments for each metal does not exceed 4%

  1. Estimating Radar Velocity using Direction of Arrival Measurements

    Doerry, Armin Walter [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Horndt, Volker [General Atomics Aeronautical Systems, Inc., San Diego, CA (United States); Bickel, Douglas Lloyd [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Naething, Richard M. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2014-09-01

    Direction of Arrival (DOA) measurements, as with a monopulse antenna, can be compared against Doppler measurements in a Synthetic Aperture Radar ( SAR ) image to determine an aircraft's forward velocity as well as its crab angle, to assist the aircraft's navigation as well as improving high - performance SAR image formation and spatial calibration.

  2. Analysis of electromagnetic field of direct action solenoid valve with current changing

    Liu Qianfeng; Bo Hanliang; Qin Benke

    2009-01-01

    Control rod hydraulic drive mechanism(CRHDM) is a newly invented patent of Institute of Nuclear and New Energy Technology of Tsinghua University. The direct action solenoid valve is the key part of this technology, so the performance of the solenoid valve directly affects the function of the CRHDM. With the current and the air gap changing,the electromagnetic field of the direct action solenoid valve was analyzed using the ANSYS software,which was validated by the experiment. The result shows that the electromagnetic force of the solenoid valve increases with the current increasing or the gap between the two armatures decreasing. Further more, the working current was confirmed. (authors)

  3. Cryogenic Current Comparator for Absolute Measurement of the Dark Current of the Superconducting Cavities for Tesla

    Knaack, K; Wittenburg, K

    2003-01-01

    A newly high performance SQUID based measurement system for detecting dark currents, generated by superconducting cavities for TESLA is proposed. It makes use of the Cryogenic Current Comparator principle and senses dark currents in the nA range with a small signal bandwidth of 70 kHz. To reach the maximum possible energy in the TESLA project is a strong motivation to push the gradients of the superconducting cavities closer to the physical limit of 50 MV/m. The field emission of electrons (the so called dark current) of the superconducting cavities at strong fields may limit the maximum gradient. The absolute measurement of the dark current in correlation with the gradient will give a proper value to compare and classify the cavities. This contribution describes a Cryogenic Current Comparator (CCC) as an excellent and useful tool for this purpose. The most important component of the CCC is a high performance DC SQUID system which is able to measure extremely low magnetic fields, e.g. caused by the extracted ...

  4. Direct imaging of enhanced current collection on grain boundaries of Cu(In,Ga)Se{sub 2} solar cells

    Kim, JunHo, E-mail: jhk@incheon.ac.kr [Department of Physics, Incheon National University, Incheon 406-772 (Korea, Republic of); National Center for Photovoltaics, National Renewable Energy Laboratory (NREL), Golden, Colorado 80401 (United States); Kim, SeongYeon [Department of Physics, Incheon National University, Incheon 406-772 (Korea, Republic of); Jiang, Chun-Sheng; Ramanathan, Kannan; Al-Jassim, Mowafak M. [National Center for Photovoltaics, National Renewable Energy Laboratory (NREL), Golden, Colorado 80401 (United States)

    2014-02-10

    We report on direct imaging of current collection by performing conductive atomic force microscopy (C-AFM) measurement on a complete Cu(In,Ga)Se{sub 2} solar cell. The localized current was imaged by milling away the top conductive layer of the device by repeated C-AFM scans. The result exhibits enhanced photocurrent collection on grain boundaries (GBs) of CIGS films, consistent with the argument for electric-field-assisted carrier collection on the GBs.

  5. Investigation of in vitro bone cell adhesion and proliferation on Ti using direct current stimulation

    Bodhak, Subhadip; Bose, Susmita; Kinsel, William C.; Bandyopadhyay, Amit

    2012-01-01

    Our objective was to establish an in vitro cell culture protocol to improve bone cell attachment and proliferation on Ti substrate using direct current stimulation. For this purpose, a custom made electrical stimulator was developed and a varying range of direct currents, from 5 to 25 μA, was used to study the current stimulation effect on bone cells cultured on conducting Ti samples in vitro. Cell–material interaction was studied for a maximum of 5 days by culturing with human fetal osteoblast cells (hFOB). The direct current was applied in every 8 h time interval and the duration of electrical stimulation was kept constant at 15 min for all cases. In vitro results showed that direct current stimulation significantly favored bone cell attachment and proliferation in comparison to nonstimulated Ti surface. Immunochemistry and confocal microscopy results confirmed that the cell adhesion was most pronounced on 25 μA direct current stimulated Ti surfaces as hFOB cells expressed higher vinculin protein with increasing amount of direct current. Furthermore, MTT assay results established that cells grew 30% higher in number under 25 μA electrical stimulation as compared to nonstimulated Ti surface after 5 days of culture period. In this work we have successfully established a simple and cost effective in vitro protocol offering easy and rapid analysis of bone cell–material interaction which can be used in promotion of bone cell attachment and growth on Ti substrate using direct current electrical stimulation in an in vitro model. - Highlights: ► D.C. stimulation was used to enhance in vitro bone cell adhesion and proliferation. ► Cells cultured on Ti were stimulated by using a custom made electrical stimulator. ► Optimization was performed by using a varying range of direct currents ∼ 5 to 25 μA. ► 25 μA stimulation was found most beneficial for promotion of cell adhesion/growth.

  6. Noninvasive transcranial direct current stimulation (tDCS) for the treatment of orofacial pain.

    Fricova, Jitka; Englerova, Katerina; Rokyta, Richard

    2016-10-01

    tDCS is a promising method for the treatment of chronic pain. Electrode placement locations must be chosen in accordance with the density and the time course of the current in order to prevent pathological changes in the underlying tissue. In order to reduce current spatial variability, more electrodes of the same polarity are placed in a circle around the second electrode of the opposite polarity. The applied current produced the greatest changes directly beneath the electrodes: the cathode reduces the excitability of cortical neurons, while the anode has the opposite effect. Based on inclusion criteria, 10 patients with chronic orofacial pain, secondary trigeminal neuralgia after oral surgery, were enrolled and underwent both anode and cathode stimulation. Before the first session we measured pain intensity on a numeric pain rating scale and tactile and thermal stimulation were used to assess somatosensory status. tDCS was applied for five consecutive days. At the end of tDCS application, somatosensory status was assessed again. From our results we can conclude that the application of tDCS improves the perception of some types of pain. When we increase our sample size, we would expect confirmation not only on our positive results, but also some additional findings for explaining the pathophysiology of orofacial pain. These pathophysiological findings and explanations are very important for the application of tDCS in the treatment of orofacial pain and also for other types of neuropathic pain.

  7. Influence of Concurrent Finger Movements on Transcranial Direct Current Stimulation (tDCS)-Induced Aftereffects.

    Shirota, Yuichiro; Terney, Daniella; Antal, Andrea; Paulus, Walter

    2017-01-01

    Transcranial direct current stimulation (tDCS) has been reported to have bidirectional influence on the amplitude of motor-evoked potentials (MEPs) in resting participants in a polarity-specific manner: anodal tDCS increased and cathodal tDCS decreased them. More recently, the effects of tDCS have been shown to depend on a number of additional factors. We investigated whether a small variety of movements involving target and non-target muscles could differentially modify the efficacy of tDCS. MEPs were elicited from the right first dorsal interosseous muscle, defined as the target muscle, by single pulse transcranial magnetic stimulation (TMS) over the primary motor cortex (M1). During M1 tDCS, which lasted for 10 min applying anodal, cathodal, or sham condition, the participants were instructed to squeeze a ball with their right hand (Task 1), to move their right index finger only in the medial (Task 2), in the lateral direction (Task 3), or in medial and lateral direction alternatively (Task 4). Anodal tDCS reduced MEP amplitudes measured in Task 1 and Task 2, but to a lesser extent in the latter. In Task 3, anodal tDCS led to greater MEP amplitudes than cathodal stimulation. Alternating movements resulted in no effect of tDCS on MEP amplitude (Task 4). The results are congruent with the current notion that the aftereffects of tDCS are highly variable relying on a number of factors including the type of movements executed during stimulation.

  8. Effects of Transcranial Direct Current Stimulation (tDCS) on Pain Distress Tolerance: A Preliminary Study.

    Mariano, Timothy Y; van't Wout, Mascha; Jacobson, Benjamin L; Garnaat, Sarah L; Kirschner, Jason L; Rasmussen, Steven A; Greenberg, Benjamin D

    2015-08-01

    Pain remains a critical medical challenge. Current treatments target nociception without addressing affective symptoms. Medically intractable pain is sometimes treated with cingulotomy or deep brain stimulation to increase tolerance of pain-related distress. Transcranial direct current stimulation (tDCS) may noninvasively modulate cortical areas related to sensation and pain representations. The present study aimed to test the hypothesis that cathodal ("inhibitory") stimulation targeting left dorsal anterior cingulate cortex (dACC) would increase tolerance to distress from acute painful stimuli vs anodal stimulation. Forty healthy volunteers received both anodal and cathodal stimulation. During stimulation, we measured pain distress tolerance with three tasks: pressure algometer, cold pressor, and breath holding. We measured pain intensity with a visual-analog scale before and after each task. Mixed ANOVA revealed that mean cold pressor tolerance tended to be higher with cathodal vs anodal stimulation (P = 0.055) for participants self-completing the task. Pressure algometer (P = 0.81) and breath holding tolerance (P = 0.19) did not significantly differ. The pressure algometer exhibited a statistically significant order effect irrespective of stimulation polarity (all P tDCS (P = 0.072). Although our primary results were nonsignificant, there is a preliminary suggestion that cathodal tDCS targeting left dACC may increase pain distress tolerance to cold pressor. Pressure algometer results are consistent with task-related sensitization. Future studies are needed to refine this novel approach for pain neuromodulation. Wiley Periodicals, Inc.

  9. Surface Current Measurements In Terra Nova Bay By Hf Radar

    Flocco, D.; Falco, P.; Wadhams, P.; Spezie, G.

    We present the preliminary results of a field experiment carried out within frame- work of the CLIMA project of the Italian National Programme for Antarctic Research (PNRA) and in cooperation with the Scott Polar Research Institute of Cambridge. Dur- ing the second period (02/12/1999-23/01/2000) of the XV Italian expedition a coastal radar was used to characterize the current field in the area of Terra Nova Bay (TNB). One of the aims of the CLIMA (Climatic Long-term Interactions for the Mass balance in Antarctica) project is to determine the role of the polynya in the sea ice mass bal- ance, water structure and local climate. The OSCR-II experiment was planned in order to provide surface current measurements in the area of TNB polynya, one of the most important coastal polynya of the Ross Sea. OSCR (Ocean Surface Current Radar) is a shore based, remote sensing system designed to measure sea surface currents in coastal waters. Two radar sites (a master and a slave) provide with radial current mea- surements; data combined from both sites yield the total current vector. Unfortunately the master and slave stations did not work together throughout the whole period of the experiment. A description of the experiment and a discussion of the results, will be proposed.

  10. Current distribution evaluation of dye-sensitized solar cell using HTS-SQUID-based magnetic measurement system

    Sakai, Kenji, E-mail: Sakai-k@okayama-u.ac.jp; Tanaka, Kohei; Kiwa, Toshihiko; Tsukada, Keiji

    2016-11-15

    Highlights: • Current distribution and direction of dye-sensitized solar cell (DSSC) was measured. • Electrical current flowing in the indium tin oxide (ITO) glass substrate was uniform. • The distribution of electrical current depended on I–V characteristic. • Current direction changed when the performance of DSSC is low. - Abstract: The current flowing inside a dye-sensitized solar cell (DSSC) was measured using a high-temperature superconductor superconducting quantum interference device (HTS-SQUID)-based magnetic measurement system. Further, a new evaluation method of the DSSC, which is difficult to measure using the conventional method, was investigated to improve the characteristics of the DSSC. The tangential components of the magnetic field generated from the DSSC were measured using two HTS-SQUIDs, and the intensity and direction related to the electrical current were obtained by the measured magnetic field. The DSSCs prepared with different dyes and catalytic substances showed different current-intensity mapping. The current direction was different for the DSSC with low performance. In addition, the current flowing in the ITO layer of the ITO glass substrate was also measured and the results confirmed that it had uniform distribution. These results show that the current mapping and the direction of the electrical current depend on the internal factors of the DSSC, and the detection of the magnetic field distribution generated from it is expected to lead to its new evaluation method.

  11. Psychological Therapies for Auditory Hallucinations (Voices): Current Status and Key Directions for Future Research

    Thomas, N.; Hayward, M.; Peters, E; van der Gaag, M.; Bentall, R.P.; Jenner, J.; Strauss, C.; Sommer, I.E.; Johns, L.C.; Varese, F.; Gracia-Montes, J.M.; Waters, F.; Dodgson, G.; McCarthy-Jones, S.

    2014-01-01

    This report from the International Consortium on Hallucinations Research considers the current status and future directions in research on psychological therapies targeting auditory hallucinations (hearing voices). Therapy approaches have evolved from behavioral and coping-focused interventions,

  12. Comments on: “Transcranial Direct Current Stimulation for Obsessive-Compulsive Disorder: A Systematic Review”

    Mohammad Alwardat

    2018-03-01

    Full Text Available Dear Editor, Brunelin et al. [1] recently conducted a systematic review that evaluated the effect of applied transcranial direct current stimulation (tDCS on patients with obsessive compulsive disorder (OCD.[...

  13. Measurement of MOS current mismatch in the weak inversion region

    Forti, F.; Wright, M.E.

    1994-01-01

    The MOS transistor matching properties in the weak inversion region have not received, in the past, the attention that the mismatch in the strong inversion region has. The importance of weak inversion biased transistors in low power CMOS analog systems calls for more extensive data on the mismatch in this region of operation. The study presented in this paper was motivated by the need of controlling the threshold matching in a low power, low noise amplifier discriminator circuit used in a silicon radiation detector read-out, where both the transistor dimensions and the currents had to be kept to a minimum. The authors have measured the current matching properties of MOS transistors operated in the weak inversion region. They measured a total of about 1,400 PMOS and NMOS transistors produced in four different processes and report here the results in terms of mismatch dependence on current density, device dimensions, and substrate voltage, without using any specific model for the transistor

  14. Direct Thermodynamic Measurements of the Energetics of Information Processing

    2017-08-08

    Title: Direct thermodynamic measurements of the energetics of information processing Report Term: 0-Other Email : roukes@caltech.edu Distribution...INVESTIGATOR(S): Phone Number: 6263952916 Principal: Y Name: PhD Michael L. Roukes Email : roukes@caltech.edu PARTICIPANTS: Person Months Worked: 1.00... writing of this final DURIP report. These initial data directly demonstrate our ability to drive and detect nanomechanical motion at ultralow

  15. SQUID Based Cryogenic Current Comparator for Measurements of the Dark Current of Superconducting Cavities

    Vodel, W; Neubert, R; Nietzsche, S

    2005-01-01

    This contribution presents a LTS-SQUID based Cryogenic Current Comparator (CCC) for detecting dark currents, generated e.g. by superconducting cavities for the upcoming X-FEL project at DESY. To achieve the maximum possible energy the gradients of the superconducting RF cavities should be pushed close to the physical limit of 50 MV/m. The measurement of the undesired field emission of electrons (the so-called dark current) in correlation with the gradient will give a proper value to compare and classify the cavities. The main component of the CCC is a high performance LTS-DC SQUID system which is able to measure extremely low magnetic fields, e.g. caused by the extracted dark current. For this reason the input coil of the SQUID is connected across a special designed toroidal niobium pick-up coil (inner diameter: about 100 mm) for the passing electron beam. A noise limited current resolution of nearly 2 pA/√(Hz) with a measurement bandwidth of up to 70 kHz was achieved without the pick-up coil. Now, ...

  16. Safety Parameter Considerations of Anodal Transcranial Direct Current Stimulation in Rats

    2017-10-01

    Richardson, J.D., Baker, J.M., Rorden, C., 2011. Transcranial direct current stimulation improves naming reaction time in fluent aphasia: a...AFRL-RH-WP-TR-2017-0069 Safety parameter considerations of anodal transcranial Direct Current Stimulation in rats R. Andy McKinley...response, including the time for reviewing instructions, searching existing data sources, searching existing data sources, gathering and maintaining the

  17. Outcomes in spasticity after repetitive transcranial magnetic and transcranial direct current stimulations

    Gunduz, Aysegul; Kumru, Hatice; Pascual-Leone, Alvaro

    2014-01-01

    Non-invasive brain stimulations mainly consist of repetitive transcranial magnetic stimulation and transcranial direct current stimulation. Repetitive transcranial magnetic stimulation exhibits satisfactory outcomes in improving multiple sclerosis, stroke, spinal cord injury and cerebral palsy-induced spasticity. By contrast, transcranial direct current stimulation has only been studied in post-stroke spasticity. To better validate the efficacy of non-invasive brain stimulations in improving ...

  18. Transcranial direct-current stimulation induced in stroke patients with aphasia: a prospective experimental cohort study

    Santos,Michele Devido; Gagliardi,Rubens José; Mac-Kay,Ana Paula Machado Goyano; Boggio,Paulo Sergio; Lianza,Roberta; Fregni,Felipe

    2013-01-01

    CONTEXT AND OBJECTIVE: Previous animal and human studies have shown that transcranial direct current stimulation can induce significant and lasting neuroplasticity and may improve language recovery in patients with aphasia. The objective of the study was to describe a cohort of patients with aphasia after stroke who were treated with transcranial direct current stimulation. DESIGN AND SETTING: Prospective cohort study developed in a public university hospital. METHODS: Nineteen patients with ...

  19. An accurate low current measurement circuit for heavy iron beam current monitor

    Zhou Chaoyang; Su Hong; Mao Ruishi; Dong Chengfu; Qian Yi; Kong Jie

    2012-01-01

    Heavy-ion beams at 10 6 particles per second have been applied to the treatment of deep-seated inoperable tumors in the therapy terminal of the Heavy Ion Research Facility in Lanzhou (HIRFL) which is located at the Institute of Modern Physics, Chinese Academy of Sciences (IMP, CAS). An accurate low current measurement circuit following a Faraday cup was developed to monitor the beam current at pA range. The circuit consisted of a picoammeter with a bandwidth of 1 kHz and a gated integrator (GI). A low input bias current precision amplifier and new guarding and shielding techniques were used in the picoammeter circuit which allowed as to measure current less than 1 pA with a current gain of 0.22 V/pA and noise less than 10 fA. This paper will also describe a novel compensation approach which reduced the charge injection from switches in the GI to 10 −18 C, and a T-switch configuration which was used to eliminate leakage current in the reset switch.

  20. Transcranial direct current stimulation for depression in Alzheimer's disease: study protocol for a randomized controlled trial.

    Narita, Zui; Yokoi, Yuma

    2017-06-19

    Patients with Alzheimer's disease frequently elicit neuropsychiatric symptoms as well as cognitive deficits. Above all, depression is one of the most common neuropsychiatric symptoms in Alzheimer's disease but antidepressant drugs have not shown significant beneficial effects on it. Moreover, electroconvulsive therapy has not ensured its safety for potential severe adverse events although it does show beneficial clinical effect. Transcranial direct current stimulation can be the safe alternative of neuromodulation, which applies weak direct electrical current to the brain. Although transcranial direct current stimulation has plausible evidence for its effect on depression in young adult patients, no study has explored it in older subjects with depression in Alzheimer's disease. Therefore, we present a study protocol designed to evaluate the safety and clinical effect of transcranial direct current stimulation on depression in Alzheimer's disease in subjects aged over 65 years. This is a two-arm, parallel-design, randomized controlled trial, in which patients and assessors will be blinded. Subjects will be randomized to either an active or a sham transcranial direct current stimulation group. Participants in both groups will be evaluated at baseline, immediately, and 2 weeks after the intervention. This study investigates the safety and effect of transcranial direct current stimulation that may bring a significant impact on both depression and cognition in patients with Alzheimer's disease, and may be useful to enhance their quality of life. ClinicalTrials.gov, NCT02351388 . Registered on 27 January 2015. Last updated on 30 May 2016.

  1. Multitarget transcranial direct current stimulation for freezing of gait in Parkinson's disease.

    Dagan, Moria; Herman, Talia; Harrison, Rachel; Zhou, Junhong; Giladi, Nir; Ruffini, Giulio; Manor, Brad; Hausdorff, Jeffrey M

    2018-04-01

    Recent findings suggest that transcranial direct current stimulation of the primary motor cortex may ameliorate freezing of gait. However, the effects of multitarget simultaneous stimulation of motor and cognitive networks are mostly unknown. The objective of this study was to evaluate the effects of multitarget transcranial direct current stimulation of the primary motor cortex and left dorsolateral prefrontal cortex on freezing of gait and related outcomes. Twenty patients with Parkinson's disease and freezing of gait received 20 minutes of transcranial direct current stimulation on 3 separate visits. Transcranial direct current stimulation targeted the primary motor cortex and left dorsolateral prefrontal cortex simultaneously, primary motor cortex only, or sham stimulation (order randomized and double-blinded assessments). Participants completed a freezing of gait-provoking test, the Timed Up and Go, and the Stroop test before and after each transcranial direct current stimulation session. Performance on the freezing of gait-provoking test (P = 0.010), Timed Up and Go (P = 0.006), and the Stroop test (P = 0.016) improved after simultaneous stimulation of the primary motor cortex and left dorsolateral prefrontal cortex, but not after primary motor cortex only or sham stimulation. Transcranial direct current stimulation designed to simultaneously target motor and cognitive regions apparently induces immediate aftereffects in the brain that translate into reduced freezing of gait and improvements in executive function and mobility. © 2018 International Parkinson and Movement Disorder Society. © 2018 International Parkinson and Movement Disorder Society.

  2. Arrester Resistive Current Measuring System Based on Heterogeneous Network

    Zhang, Yun Hua; Li, Zai Lin; Yuan, Feng; Hou Pan, Feng; Guo, Zhan Nan; Han, Yue

    2018-03-01

    Metal Oxide Arrester (MOA) suffers from aging and poor insulation due to long-term impulse voltage and environmental impact, and the value and variation tendency of resistive current can reflect the health conditions of MOA. The common wired MOA detection need to use long cables, which is complicated to operate, and that wireless measurement methods are facing the problems of poor data synchronization and instability. Therefore a novel synchronous measurement system of arrester current resistive based on heterogeneous network is proposed, which simplifies the calculation process and improves synchronization, accuracy and stability and of the measuring system. This system combines LoRa wireless network, high speed wireless personal area network and the process layer communication, and realizes the detection of arrester working condition. Field test data shows that the system has the characteristics of high accuracy, strong anti-interference ability and good synchronization, which plays an important role in ensuring the stable operation of the power grid.

  3. Direct liquid content measurement applicable for He II space cryostats

    Wanner, M.

    1988-01-01

    A direct calorimetric method for content measurement in the He II cryostat ISO was assessed. A well defined heat pulse into the He II bath causes a small temperature increase which can be measured and directly correlated to the liquid mass through the He II specific heat. To study this method under the potential zero gravity constraints of disconnected liquid volumes a setup was established for investigating heat transfer between separated liquid volumes. The results for different fluid configurations confirm that even for completely disconnected volumes the heat is almost immediately distributed throughout the whole liquid by evaporation and recondensation

  4. Measurement of the current in water discharge using magneto-optical Faraday effect

    Sarkisov, G.S.; Woodworth, J.R.

    2006-01-01

    The observation of magnetooptical Faraday effects in water in experiments with electrical breakdown is presented. After high-voltage breakdown, the ionized channel with ∼4 kA current was generated. The magnetic field from the current channel induces a circular birefringence which results in rotation of the polarization plane of a probing laser (200 ps, 532 nm). In spite of fast opposite radius drop of the magnetic field in radial direction, the Faraday rotation effect drops very slowly. The rotation of the polarization plane was ∼0.65 deg. ±5%. The optical measurements are in good agreement within ∼7% with the electrical measurements of the current

  5. Notes on Human Trials of Transcranial Direct Current Stimulation between 1960 and 1998

    Esmaeilpour, Zeinab; Schestatsky, Pedro; Bikson, Marom; Brunoni, André R.; Pellegrinelli, Ada; Piovesan, Fernanda X.; Santos, Mariana M. S. A.; Menezes, Renata B.; Fregni, Felipe

    2017-01-01

    Background: Transcranial direct current stimulation (tDCS) is investigated to modulate neuronal function including cognitive neuroscience and neuropsychiatric therapies. While cases of human stimulation with rudimentary batteries date back more than 200 years, clinical trials with current controlled stimulation were published intermittently since the 1960s. The modern era of tDCS only started after 1998. Objectives: To review methods and outcomes of tDCS studies from old literature (between 1960 and 1998) with intention of providing new insight for ongoing tDCS trials and development of tDCS protocols especially for the purpose of treatment. Methods: Articles were identified through a search in PubMed and through the reference list from its selected articles. We included only non-invasive human studies that provided controlled direct current and were written in English, French, Spanish or Portuguese before the year of 1998, the date in which modern stimulation paradigms were implemented. Results: Fifteen articles met our criteria. The majority were small-randomized controlled clinical trials that enrolled a mean of approximately 26 subjects (Phase II studies). Most of the studies (around 83%) assessed the role of tDCS in the treatment of psychiatric conditions, in which the main outcomes were measured by means of behavioral scales and clinical observation, but the diagnostic precision and the quality of outcome monitoring, including adverse events, were deficient by modern standards. Compared to modern tDCS dose, the stimulation intensities used (0.1–1 mA) were lower, however as the electrodes were typically smaller (e.g., 1.26 cm2), the average electrode current density (0.2 mA/cm2) was approximately 4× higher. The number of sessions ranged from one to 120 (median 14). Notably, the stimulation session durations of several minutes to 11 h (median 4.5 h) could markedly exceed modern tDCS protocols. Twelve studies out of 15 showed positive results. Only mild side

  6. Impact of transcranial direct current stimulation (tDCS) on neuronal functions

    Das, S. (Suman); P.J. Holland (Peter); M.A. Frens (Maarten); O. Donchin (Opher)

    2016-01-01

    textabstractTranscranial direct current stimulation (tDCS), a non-invasive brain stimulation technique, modulates neuronal excitability by the application of a small electrical current. The low cost and ease of the technique has driven interest in potential clinical applications. However, outcomes

  7. Four-point probe measurements using current probes with voltage feedback to measure electric potentials

    Lüpke, Felix; Cuma, David; Korte, Stefan; Cherepanov, Vasily; Voigtländer, Bert

    2018-02-01

    We present a four-point probe resistance measurement technique which uses four equivalent current measuring units, resulting in minimal hardware requirements and corresponding sources of noise. Local sample potentials are measured by a software feedback loop which adjusts the corresponding tip voltage such that no current flows to the sample. The resulting tip voltage is then equivalent to the sample potential at the tip position. We implement this measurement method into a multi-tip scanning tunneling microscope setup such that potentials can also be measured in tunneling contact, allowing in principle truly non-invasive four-probe measurements. The resulting measurement capabilities are demonstrated for \

  8. Direct numerical simulations of particle-laden density currents with adaptive, discontinuous finite elements

    S. D. Parkinson

    2014-09-01

    Full Text Available High-resolution direct numerical simulations (DNSs are an important tool for the detailed analysis of turbidity current dynamics. Models that resolve the vertical structure and turbulence of the flow are typically based upon the Navier–Stokes equations. Two-dimensional simulations are known to produce unrealistic cohesive vortices that are not representative of the real three-dimensional physics. The effect of this phenomena is particularly apparent in the later stages of flow propagation. The ideal solution to this problem is to run the simulation in three dimensions but this is computationally expensive. This paper presents a novel finite-element (FE DNS turbidity current model that has been built within Fluidity, an open source, general purpose, computational fluid dynamics code. The model is validated through re-creation of a lock release density current at a Grashof number of 5 × 106 in two and three dimensions. Validation of the model considers the flow energy budget, sedimentation rate, head speed, wall normal velocity profiles and the final deposit. Conservation of energy in particular is found to be a good metric for measuring model performance in capturing the range of dynamics on a range of meshes. FE models scale well over many thousands of processors and do not impose restrictions on domain shape, but they are computationally expensive. The use of adaptive mesh optimisation is shown to reduce the required element count by approximately two orders of magnitude in comparison with fixed, uniform mesh simulations. This leads to a substantial reduction in computational cost. The computational savings and flexibility afforded by adaptivity along with the flexibility of FE methods make this model well suited to simulating turbidity currents in complex domains.

  9. Time structure measurement of the ATLAS RPC gap current

    Aielli, G; The ATLAS collaboration

    2010-01-01

    The current absorbed by an RPC represents the sum of the charge delivered in the gas by the ionizing events interesting the gap, integrated by the electrodes time constant. This is typically of the order of tens of ms thus dominating the gas discharge time scale and characterizing the granular structure observed in the current signal. In most cases this structure is considered as noise to be further integrated to observe the average gap current, used often as a detector monitoring parameter or to precisely measure the uncorrelated background rate effects. A remarkable case is given if a large number of particles is passing trough the detector within an integration time constant producing a current peak clearly detectable above the average noise. The ATLAS RPC system is equipped with a dedicated current monitoring based on an ADC capable of reading out the average value as well as the transient peaks of the currents above a given threshold. A study on such data was used to spot the gap HV noise, to monitor the...

  10. A Review of Player Monitoring Approaches in Basketball: Current Trends and Future Directions.

    Fox, Jordan L; Scanlan, Aaron T; Stanton, Robert

    2017-07-01

    Fox, JL, Scanlan, AT, and Stanton, R. A review of player monitoring approaches in basketball: current trends and future directions. J Strength Cond Res 31(7): 2021-2029, 2017-Effective monitoring of players in team sports such as basketball requires an understanding of the external demands and internal responses, as they relate to training phases and competition. Monitoring of external demands and internal responses allows coaching staff to determine the dose-response associated with the imposed training load (TL), and subsequently, if players are adequately prepared for competition. This review discusses measures reported in the literature for monitoring the external demands and internal responses of basketball players during training and competition. The external demands of training and competition were primarily monitored using time-motion analysis, with limited use of microtechnology being reported. Internal responses during training were typically measured using hematological markers, heart rate, various TL models, and perceptual responses such as rating of perceived exertion (RPE). Heart rate was the most commonly reported indicator of internal responses during competition with limited reporting of hematological markers or RPE. These findings show a large discrepancy between the reporting of external and internal measures and training and competition demands. Microsensors, however, may be a practical and convenient method of player monitoring in basketball to overcome the limitations associated with current approaches while allowing for external demands and internal responses to be recorded simultaneously. The triaxial accelerometers of microsensors seem well suited for basketball and warrant validation to definitively determine their place in the monitoring of basketball players. Coaching staff should make use of this technology by tracking individual player responses across the annual plan and using real-time monitoring to minimize factors such as fatigue

  11. Directivity measurements in aluminum using a laser ultrasonics system

    Sakamoto, J M S; Pacheco, G M; Tittmann, B R; Baba, A

    2011-01-01

    A laser ultrasonics system was setup to measure the directivity (angular dependence pattern) of the amplitude of ultrasonic waves generated in aluminum samples. A pulsed Nd:YAG laser operating at 1064 nm optical wavelength, with typical pulse width (FWHM) of 8 ns, and energy per pulse of 450 mJ, was used to generate the ultrasound waves in the samples. The laser detection system was a Mach-Zehnder interferometer with typical noise-limited resolution of 0.25 nm (rms), frequency range from 50 kHz to 20 MHz, and measurement range from -75 nm/V to +75 nm/V. Two different optical spot sizes of the Nd:YAG laser were used to generate waves in the ablation regime: one was focused and the other was unfocused. Using the obtained data, the directivity graphics were drawn and compared with the theoretical curves, showing a good agreement. The experiments showed the directivity as a function of the optical spot size. For a point ultrasonic source (or focused optical spot), the directivity shows that the longitudinal waves present considerable amplitude in all directions. For a larger ultrasonic source (or an unfocused optical spot) the directivity shows that the longitudinal waves are generated with the higher amplitudes inside angles around ±10 0 .

  12. Individualized model predicts brain current flow during transcranial direct-current stimulation treatment in responsive stroke patient.

    Datta, Abhishek; Baker, Julie M; Bikson, Marom; Fridriksson, Julius

    2011-07-01

    Although numerous published reports have demonstrated the beneficial effects of transcranial direct-current stimulation (tDCS) on task performance, fundamental questions remain regarding the optimal electrode configuration on the scalp. Moreover, it is expected that lesioned brain tissue will influence current flow and should therefore be considered (and perhaps leveraged) in the design of individualized tDCS therapies for stroke. The current report demonstrates how different electrode configurations influence the flow of electrical current through brain tissue in a patient who responded positively to a tDCS treatment targeting aphasia. The patient, a 60-year-old man, sustained a left hemisphere ischemic stroke (lesion size = 87.42 mL) 64 months before his participation. In this study, we present results from the first high-resolution (1 mm(3)) model of tDCS in a brain with considerable stroke-related damage; the model was individualized for the patient who received anodal tDCS to his left frontal cortex with the reference cathode electrode placed on his right shoulder. We modeled the resulting brain current flow and also considered three additional reference electrode positions: right mastoid, right orbitofrontal cortex, and a "mirror" configuration with the anode over the undamaged right cortex. Our results demonstrate the profound effect of lesioned tissue on resulting current flow and the ability to modulate current pattern through the brain, including perilesional regions, through electrode montage design. The complexity of brain current flow modulation by detailed normal and pathologic anatomy suggest: (1) That computational models are critical for the rational interpretation and design of individualized tDCS stroke-therapy; and (2) These models must accurately reproduce head anatomy as shown here. Copyright © 2011 Elsevier Inc. All rights reserved.

  13. Psychological Therapies for Auditory Hallucinations (Voices): Current Status and Key Directions for Future Research

    Thomas, Neil; Hayward, Mark; Peters, Emmanuelle; van der Gaag, Mark; Bentall, Richard P.; Jenner, Jack; Strauss, Clara; Sommer, Iris E.; Johns, Louise C.; Varese, Filippo; García-Montes, José Manuel; Waters, Flavie; Dodgson, Guy; McCarthy-Jones, Simon

    2014-01-01

    This report from the International Consortium on Hallucinations Research considers the current status and future directions in research on psychological therapies targeting auditory hallucinations (hearing voices). Therapy approaches have evolved from behavioral and coping-focused interventions, through formulation-driven interventions using methods from cognitive therapy, to a number of contemporary developments. Recent developments include the application of acceptance- and mindfulness-based approaches, and consolidation of methods for working with connections between voices and views of self, others, relationships and personal history. In this article, we discuss the development of therapies for voices and review the empirical findings. This review shows that psychological therapies are broadly effective for people with positive symptoms, but that more research is required to understand the specific application of therapies to voices. Six key research directions are identified: (1) moving beyond the focus on overall efficacy to understand specific therapeutic processes targeting voices, (2) better targeting psychological processes associated with voices such as trauma, cognitive mechanisms, and personal recovery, (3) more focused measurement of the intended outcomes of therapy, (4) understanding individual differences among voice hearers, (5) extending beyond a focus on voices and schizophrenia into other populations and sensory modalities, and (6) shaping interventions for service implementation. PMID:24936081

  14. Current limiting characteristics of transformer type SFCL with coupled secondary windings according to its winding direction

    Lim, Sung Hun [Dept. of Electrical Engineering, Soongsil University, Seoul (Korea, Republic of); Han, Tae Hee [Dept. of Aero Materials Engineering, Jungwon University, Goesan (Korea, Republic of)

    2017-06-15

    In this paper, the current limiting characteristics of the transformer type superconducting fault current limiter (SFCL) with the two coupled secondary windings due to its winding direction were analyzed. To analyze the dependence of transient fault current limiting characteristics on the winding direction of the additional secondary winding, the fault current limiting tests of the SFCL with an additional secondary winding, wound as subtractive polarity winding and additive polarity winding, were carried out. The time interval of quench occurrence between two superconducting elements comprising the transformer type SFCL with the additional secondary winding was confirmed to be affected by the winding direction of the additional secondary winding. In case of the subtractive polarity winding of the additional secondary winding, the time interval of the quench occurrence in two superconducting elements was shorter than the case of the additive polarity winding.

  15. Current limiting characteristics of transformer type SFCL with coupled secondary windings according to its winding direction

    Lim, Sung Hun; Han, Tae Hee

    2017-01-01

    In this paper, the current limiting characteristics of the transformer type superconducting fault current limiter (SFCL) with the two coupled secondary windings due to its winding direction were analyzed. To analyze the dependence of transient fault current limiting characteristics on the winding direction of the additional secondary winding, the fault current limiting tests of the SFCL with an additional secondary winding, wound as subtractive polarity winding and additive polarity winding, were carried out. The time interval of quench occurrence between two superconducting elements comprising the transformer type SFCL with the additional secondary winding was confirmed to be affected by the winding direction of the additional secondary winding. In case of the subtractive polarity winding of the additional secondary winding, the time interval of the quench occurrence in two superconducting elements was shorter than the case of the additive polarity winding

  16. Writer identification using directional ink-trace width measurements

    Brink, A. A.; Smit, J.; Bulacu, M. L.; Schomaker, L. R. B.

    As suggested by modern paleography, the width of ink traces is a powerful source of information for off-line writer identification, particularly if combined with its direction. Such measurements can be computed using simple, fast and accurate methods based on pixel contours, the combination of which

  17. Convergence of Algorithms for Reconstructing Convex Bodies and Directional Measures

    Gardner, Richard; Kiderlen, Markus; Milanfar, Peyman

    2006-01-01

    We investigate algorithms for reconstructing a convex body K in Rn from noisy measurements of its support function or its brightness function in k directions u1, . . . , uk. The key idea of these algorithms is to construct a convex polytope Pk whose support function (or brightness function) best...

  18. New Technique of Direct Intra-abdominal Pressure Measurement

    Elena Risin

    2006-10-01

    Conclusion: Direct measurement of intra-abdominal pressure using 14-Fr PVC round drain is a newly described technique that is simple, fast and credible. Future investigation will be needed to confirm the reliability of this method during postoperative follow-up of intra-abdominal pressures in selected patients.

  19. Can Transcranial Direct Current Stimulation Improve Cognitive Functioning in Adults with Schizophrenia?

    Schretlen, David J; van Steenburgh, Joseph J; Varvaris, Mark; Vannorsdall, Tracy D; Andrejczuk, Megan A; Gordon, Barry

    Cognitive impairment is nearly ubiquitous in schizophrenia. First-degree relatives of persons with schizophrenia often show similar but milder deficits. Current methods for the treatment of schizophrenia are often ineffective in cognitive remediation. Since transcranial direct current stimulation (tDCS) can enhance cognitive functioning in healthy adults, it might provide a viable option to enhance cognition in schizophrenia. We sought to explore whether tDCS can be tolerated by persons with schizophrenia and potentially improve their cognitive functioning. We examined the effects of anodal versus cathodal tDCS on working memory and other cognitive tasks in five outpatients with schizophrenia and six first-degree relatives of persons with schizophrenia. Each participant completed tasks thought to be mediated by the prefrontal cortex during two 30-minute sessions of tDCS to the left and right dorsolateral prefrontal cortex (DLPFC). Anodal stimulation over the left DLPFC improved performance relative to cathodal stimulation on measures of working memory and aspects of verbal fluency relevant to word retrieval. The patient group showed differential changes in novel design production without alteration of overall productivity, suggesting that tDCS might be capable of altering self-monitoring and executive control. All participants tolerated tDCS well. None withdrew from the study or experienced any adverse reaction. We conclude that adults with schizophrenia can tolerate tDCS while engaging in cognitive tasks and that tDCS can alter their performance.

  20. Sex Mediates the Effects of High-Definition Transcranial Direct Current Stimulation on "Mind-Reading".

    Martin, A K; Huang, J; Hunold, A; Meinzer, M

    2017-12-16

    Sex differences in social cognitive ability are well established, including measures of Theory of Mind (ToM). The aim of this study was to investigate if sex mediates the effects of high-definition transcranial direct current stimulation (HD-tDCS) administered to a key hub of the social brain (i.e., the dorsomedial prefrontal cortex, dmPFC) on the Reading the Mind in the Eyes Test (RMET). Forty healthy young adults (18-35 years) were randomly allocated to receive either anodal or cathodal HD-tDCS in sham HD-tDCS controlled, double blind designs. In each of the two sessions, subjects completed the RMET. Anodal stimulation to the dmPFC increased accuracy on the RMET in females only. To assure regional specificity we performed a follow-up study stimulating the right temporoparietal junction and found no effect in either sex. The current study is the first to show improved performance on the RMET after tDCS to the dmPFC in females only. The polarity-specific effects and use of focal HD-tDCS provide evidence for sex-dependent differences in dmPFC function in relation to the RMET. Future studies using tDCS to study or improve ToM, need to consider sex. Copyright © 2017 IBRO. Published by Elsevier Ltd. All rights reserved.

  1. The control of the upstream movement of fish with pulsated direct current

    McLain, Alberton L.

    1957-01-01

    Alternating-current electromechanical devices installed in the mouths of streams have proved effective in stopping the spawning migrations of the parasitic sea lamprey (Petromyzon marinus) which has seriously damaged Great Lakes fisheries. In a few streams, excessive mortality has occurred to other fish at the alternating-current barriers. A direct-current unit was developed in an attempt to reduce this mortality. This direct-current “diversion device” consists of a row of suspended negative electrodes which begins at the end of a trap wing and extends across the river at a downstream angle of 45° and a series of pipes (positive electrodes) driven into the stream bank. A second array, consisting of horizontal pipes installed downstream and parallel to the suspended electrodes and connected to a series of rods driven into the bank near the positive electrodes, controls the electrical field and dissipates the collecting influence of the positive side of the circuit. The electrical field is established from the end of the trap wing to the opposite bank. Fish are diverted away from the negative electrodes and toward the bank near which the trap is located. The array is activiated by pulsated direct current of essentially square wave shape with pulses at a duty cycle of 0.66 and a repetition rate of 3 per second. Direct-current diversion devices were operated in conjunction with alternating-current barriers during 1956 in the Chocolay River, Marquette County, and the Silver River, Baraga County, Michigan.

  2. Plasma position from ring current measurements in Extrap T1

    Brunsell, P.; Jin Li.

    1989-11-01

    The inductive coupling between the plasma and the four octupole field coils in the Extrap T1 device is utilized as a means of estimating the plasma position. The current in each octupole ring as well as the plasma current is measured by a Rogowski coil and the ring - plasma mutual inductance is then computed assuming axisymmetric plasma displacements. The obtained position is in agreement with internal magnetic probe measurements. The time - evolution of the plasma position for different external vertical and toroidal field strengths is studied. For the present discharge parameter a vertical field of about .008 T is found to give an almost radially stationary plasma. The results are compared with a simple equilibrium model

  3. Performance analysis and evaluation of direct phase measuring deflectometry

    Zhao, Ping; Gao, Nan; Zhang, Zonghua; Gao, Feng; Jiang, Xiangqian

    2018-04-01

    Three-dimensional (3D) shape measurement of specular objects plays an important role in intelligent manufacturing applications. Phase measuring deflectometry (PMD)-based methods are widely used to obtain the 3D shapes of specular surfaces because they offer the advantages of a large dynamic range, high measurement accuracy, full-field and noncontact operation, and automatic data processing. To enable measurement of specular objects with discontinuous and/or isolated surfaces, a direct PMD (DPMD) method has been developed to build a direct relationship between phase and depth. In this paper, a new virtual measurement system is presented and is used to optimize the system parameters and evaluate the system's performance in DPMD applications. Four system parameters are analyzed to obtain accurate measurement results. Experiments are performed using simulated and actual data and the results confirm the effects of these four parameters on the measurement results. Researchers can therefore select suitable system parameters for actual DPMD (including PMD) measurement systems to obtain the 3D shapes of specular objects with high accuracy.

  4. Quantifying short-lived events in multistate ionic current measurements.

    Balijepalli, Arvind; Ettedgui, Jessica; Cornio, Andrew T; Robertson, Joseph W F; Cheung, Kin P; Kasianowicz, John J; Vaz, Canute

    2014-02-25

    We developed a generalized technique to characterize polymer-nanopore interactions via single channel ionic current measurements. Physical interactions between analytes, such as DNA, proteins, or synthetic polymers, and a nanopore cause multiple discrete states in the current. We modeled the transitions of the current to individual states with an equivalent electrical circuit, which allowed us to describe the system response. This enabled the estimation of short-lived states that are presently not characterized by existing analysis techniques. Our approach considerably improves the range and resolution of single-molecule characterization with nanopores. For example, we characterized the residence times of synthetic polymers that are three times shorter than those estimated with existing algorithms. Because the molecule's residence time follows an exponential distribution, we recover nearly 20-fold more events per unit time that can be used for analysis. Furthermore, the measurement range was extended from 11 monomers to as few as 8. Finally, we applied this technique to recover a known sequence of single-stranded DNA from previously published ion channel recordings, identifying discrete current states with subpicoampere resolution.

  5. High-temperature ultrasonic measurements applied to directly heated samples

    Moore, R.I.; Taylor, R.E.

    1984-01-01

    High-temperature ultrasonic measurements of Young's modulus were made of graphite samples heated directly. The samples were cylindrical rods of the same geometry as that used in the multiproperty apparatus for simultaneous/consecutive measurements of a number of thermophysical properties to high temperatures. The samples were resonated in simple longitudinal vibration modes. Measurements were performed up to 2000 K. Incorporation of ultrasonic measurements of Young's modulus in the capabilities of the multiproperty apparatus is valuable because (i) ultrasonic measurements can be related to normal destructive measurements of this property; (ii) they can be used for screening materials or acceptance testing of specimens; (iii) they can be used to increase the understanding of thermophysical properties and property correlations. (author)

  6. AN INDUCTION SENSOR FOR MEASURING CURRENTS OF NANOSECOND RANGE

    S. P. Shalamov

    2016-11-01

    Full Text Available Purpose. A current meter based on the principle of electromagnetic induction is designed to register the current flowing in the rod lightning. The aim of the article is to describe the way of increasing the sensitivity of the converter by means of their serial communication. Methodology. The recorded current is in the nanosecond range. If compared with other methods, meters based on the principle of electromagnetic induction have several advantages, such as simplicity of construction, reliability, low cost, no need in a power source, relatively high sensitivity. Creation of such a meter is necessary, because in some cases there is no possibility to use a shunt. Transient properties of a meter are determined by the number of turns and the constant of integration. Sensitivity is determined by measuring the number of turns, the coil sectional area, the core material and the integration constant. For measuring the magnetic field pulses with a rise time of 5 ns to 50 ns a meter has turns from 5 to 15. The sensitivity of such a meter is low. When the number of turns is increased, the output signal and the front increase. Earlier described dependencies were used to select the main parameters of the converter. It was based on generally accepted and widely known equivalent circuit. The experience of created earlier pulse magnetic field meters was considered both for measuring the magnetic fields, and large pulse current. Originality. Series connection of converters has the property of a long line. The level of the transient response of the meter is calculated. The influence of parasitic parameters on the type of meter transient response is examined. The shown construction was not previously described. Practical value. The results of meter implementation are given. The design peculiarities of the given measuring instruments are shown.

  7. Direct measurement of annual β dose using TLD on porcelain

    Leung, P.L.; Stokes, M.J.; Xia Junding; Wang Weida; Zhou Zhixin

    1999-01-01

    In order to improve accuracy of TL authentication test for porcelain, a method of direct measurement of annual β dose using ultrathin TLD (CaSO 4 :Tm) on porcelain was studied. Since the TLD was placed into a hole left after sampling for the TL measurement, the method will not cause any new damage to the studied object. The results show that the technique is suitable for measuring annual β dose and improving accuracy of TL authentication test for both porcelain and pottery

  8. Measurement of proton momentum distributions using a direct geometry instrument

    Senesi, R; Andreani, C; Kolesnikov, A I

    2014-01-01

    We report the results of inelastic neutron scattering measurements on bulk water and ice using the direct geometry SEQUOIA chopper spectrometer at the Spallation Neutron Source (USA), with incident energy E i = 6 eV. In this set up the measurements allow to access the Deep Inelastic Neutron Scattering regime. The scattering is centred at the proton recoil energy given by the impulse approximation, and the shape of the recoil peak conveys information on the proton momentum distribution in the system. The comparison with the performance of inverse geometry instruments, such as VESUVIO at the ISIS source (UK), shows that complementary information can be accessed by the use of direct and inverse geometry instruments. Analysis of the neutron Compton profiles shows that the proton kinetic energy in ice at 271 K is larger than in room temperature liquid water, in agreement with previous measurements on VESUVIO

  9. Performance evaluation of directly photovoltaic powered DC PM (direct current permanent magnet) motor – propeller thrust system

    Atlam, Ozcan; Kolhe, Mohan

    2013-01-01

    Photovoltaic (PV) powered directly coupled electro-mechanical system has wide applications (e.g. PV powered cooling fans in green houses, PV water pumping system, solar vehicles). The objective of this work is to analyse the operation of directly PV powered DC PM (direct current permanent magnet) motor – propeller system for selection of motor parameters. The performance of such system mainly depends on the incident solar radiation, operating cell temperature, DC motor and propeller load parameters. It is observed that the operating points of the PV DC PM motor – propeller system matches very closely with the maximum power points (MPPs) of the PV array, if the DC PM motor – propeller parameters have been properly selected. It is found that for a specific application of such type of system, matching of torque–speed operating points with respect to the maximum power points of PV array are very important. It is ascertained through results that the DC PM motor's armature resistance, magnetic field constant, starting current to overcome the starting torque and torque coefficient are the main parameters. In designing a PV powered DC PM motor for a specific application, selection of these parameters are important for maximum utilization of the PV array output. The results of this system are useful for designing of directly PV powered DC PM motor's for aerodynamic applications. - Highlights: • We analyse the performance of directly PV powered DC PM motor – propeller system. • We examine PV electro-mechanical system for selection of DC motor parameters. • Matching of torque–speed curve to maximum power points of PV array is important

  10. An Intrinsic Fiber-Optic Sensor for Structure Lightning Current Measurement

    Nguyen, Truong X.; Ely, Jay J.; Szatkowski, George N.; Mata, Carlos T.; Mata, Angel. G.; Snyder, Gary P.

    2014-01-01

    An intrinsic optical-fiber sensor based on Faraday Effect is developed that is highly suitable for measuring lightning current on aircraft, towers and complex structures. Originally developed specifically for aircraft installations, it is light-weight, non-conducting, structure conforming, and is immune to electromagnetic interference, hysteresis and saturation. It can measure total current down to DC. When used on lightning towers, the sensor can help validate other sensors and lightning detection network measurements. Faraday Effect causes light polarization to rotate when the fiber is exposed to a magnetic field in the direction of light propagation. Thus, the magnetic field strength can be determined from the light polarization change. By forming closed fiber loops and applying Ampere's law, measuring the total light rotation yields the total current enclosed. A broadband, dual-detector, reflective polarimetric scheme allows measurement of both DC component and AC waveforms with a 60 dB dynamic range. Two systems were built that are similar in design but with slightly different sensitivities. The 1310nm laser system can measure 300 A - 300 kA, and has a 15m long sensing fiber. It was used in laboratory testing, including measuring current on an aluminum structure simulating an aircraft fuselage or a lightning tower. High current capabilities were demonstrated up to 200 kA at a lightning test facility. The 1550nm laser system can measure 400 A - 400 kA and has a 25m fiber length. Used in field measurements, excellent results were achieved in the summer of 2012 measuring rocket-triggered lightning at the International Center for Lightning Research and Testing (ICLRT), Camp Blanding, Florida. In both systems increased sensitivity can be achieved with multiple fiber loops. The fiber optic sensor provides many unique capabilities not currently possible with traditional sensors. It represents an important new tool for lightning current measurement where low weight

  11. Comparison of NWP wind speeds and directions to measured wind speeds and directions

    Astrup, Poul; Mikkelsen, Torben

    Numerical Weather Predictions (NWP) of wind speed and direction has been compared to measurements for seven German sites for nuclear power plants, and for Risø, the site of the Danish nuclear research reactors now being decommissioned . For the German sites the data cover approximately three month...

  12. Transcutaneous spinal direct current stimulation induces lasting fatigue resistance and enhances explosive vertical jump performance

    Tate, Rothwelle J.; Conway, Bernard A.

    2017-01-01

    Transcutaneous spinal direct current stimulation (tsDCS) is a non-invasive neuromodulatory intervention that has been shown to modify excitability in spinal and supraspinal circuits in animals and humans. Our objective in this study was to explore the functional neuromodulatory potential of tsDCS by examining its immediate and lasting effects over the repeated performance of a whole body maximal exercise in healthy volunteers. Using a double-blind, randomized, crossover, sham-controlled design we investigated the effects of 15 min of anodal tsDCS on repeated vertical countermovement jump (VCJ) performance at 0, 20, 60, and 180 minutes post-stimulation. Measurements of peak and take-off velocity, vertical displacement, peak power and work done during countermovement and push-off VCJ phases were derived from changes in vertical ground reaction force (12 performance parameters) in 12 healthy participants. The magnitude and direction of change in VCJ performance from pre- to post-stimulation differed significantly between sham and active tsDCS for 7 of the 12 VCJ performance measures (P 0.05). Our original findings demonstrate that one single session of anodal tsDCS in healthy subjects can prevent fatigue and maintain or enhance different aspects of whole body explosive motor power over repeated sets of VCJs performed over a period of three hours. The observed effects are discussed in relation to alterations in central fatigue mechanisms, muscle contraction mode during jump execution and changes in spinal cord excitability. These findings have important implications for power endurance sport performance and for neuromotor rehabilitation. PMID:28379980

  13. Transcutaneous spinal direct current stimulation induces lasting fatigue resistance and enhances explosive vertical jump performance.

    Helen R Berry

    Full Text Available Transcutaneous spinal direct current stimulation (tsDCS is a non-invasive neuromodulatory intervention that has been shown to modify excitability in spinal and supraspinal circuits in animals and humans. Our objective in this study was to explore the functional neuromodulatory potential of tsDCS by examining its immediate and lasting effects over the repeated performance of a whole body maximal exercise in healthy volunteers. Using a double-blind, randomized, crossover, sham-controlled design we investigated the effects of 15 min of anodal tsDCS on repeated vertical countermovement jump (VCJ performance at 0, 20, 60, and 180 minutes post-stimulation. Measurements of peak and take-off velocity, vertical displacement, peak power and work done during countermovement and push-off VCJ phases were derived from changes in vertical ground reaction force (12 performance parameters in 12 healthy participants. The magnitude and direction of change in VCJ performance from pre- to post-stimulation differed significantly between sham and active tsDCS for 7 of the 12 VCJ performance measures (P 0.05. Our original findings demonstrate that one single session of anodal tsDCS in healthy subjects can prevent fatigue and maintain or enhance different aspects of whole body explosive motor power over repeated sets of VCJs performed over a period of three hours. The observed effects are discussed in relation to alterations in central fatigue mechanisms, muscle contraction mode during jump execution and changes in spinal cord excitability. These findings have important implications for power endurance sport performance and for neuromotor rehabilitation.

  14. Current measurement system utilizing cryogenic techniques for the absolute measurement of the magnetic flux quantum

    Endo, T.; Murayama, Y.; Sakamoto, Y.; Sakuraba, T.; Shiota, F.

    1989-01-01

    A series of systems composed of cryogenic devices such as a Josephson potentiometer and a cryogenic current comparator has been proposed and developed to precisely measure a current with any value up to 1 A. These systems will be used to measure the injected electrical energy with an uncertainty of the order of 0.01 ppm or less in the absolute measurement of the magnetic flux quantum by superconducting magnetic levitation. Some preliminary experiments are described

  15. Feasibility of transcranial direct current stimulation use in children aged 5 to 12 years.

    Andrade, Agnes Carvalho; Magnavita, Guilherme Moreira; Allegro, Juleilda Valéria Brasil Nunes; Neto, Carlos Eduardo Borges Passos; Lucena, Rita de Cássia Saldanha; Fregni, Felipe

    2014-10-01

    Transcranial direct current stimulation is a noninvasive brain stimulation technique that has been studied for the treatment of neuropsychiatric disorders in adults, with minimal side effects. The objective of this study is to report the feasibility, tolerability, and the short-term adverse effects of transcranial direct current stimulation in children from 5 to 12 years of age. It is a naturalistic study of 14 children who underwent 10 sessions of transcranial direct current stimulation as an alternative, off-label, and open-label treatment for various languages disorders. Frequency, intensity, adverse effects, and perception of improvement reported by parents were collected. The main side effects detected were tingling (28.6%) and itching (28.6%), acute mood changes (42.9%), and irritability (35.7%). Transcranial direct current stimulation is a feasible and tolerable technique in children, although studies regarding plastic and cognitive changes in children are needed to confirm its safety. In conclusion, this is a naturalistic report in which we considered transcranial direct current stimulation as feasible in children. © The Author(s) 2013.

  16. Modulation of mu rhythm desynchronization during motor imagery by transcranial direct current stimulation

    Kimura Akio

    2010-06-01

    Full Text Available Abstract Background The mu event-related desynchronization (ERD is supposed to reflect motor preparation and appear during motor imagery. The aim of this study is to examine the modulation of ERD with transcranial direct current stimulation (tDCS. Methods Six healthy subjects were asked to imagine their right hand grasping something after receiving a visual cue. Electroencephalograms (EEGs were recorded near the left M1. ERD of the mu rhythm (mu ERD by right hand motor imagery was measured. tDCS (10 min, 1 mA was used to modulate the cortical excitability of M1. Anodal, cathodal, and sham tDCS were tested in each subject with a randomized sequence on different days. Each condition was separated from the preceding one by more than 1 week in the same subject. Before and after tDCS, mu ERD was assessed. The motor thresholds (MT of the left M1 were also measured with transcranial magnetic stimulation. Results Mu ERD significantly increased after anodal stimulation, whereas it significantly decreased after cathodal stimulation. There was a significant correlation between mu ERD and MT. Conclusions Opposing effects on mu ERD based on the orientation of the stimulation suggest that mu ERD is affected by cortical excitability.

  17. Monitoring transcranial direct current stimulation induced changes in cortical excitability during the serial reaction time task.

    Ambrus, Géza Gergely; Chaieb, Leila; Stilling, Roman; Rothkegel, Holger; Antal, Andrea; Paulus, Walter

    2016-03-11

    The measurement of the motor evoked potential (MEP) amplitudes using single pulse transcranial magnetic stimulation (TMS) is a common method to observe changes in motor cortical excitability. The level of cortical excitability has been shown to change during motor learning. Conversely, motor learning can be improved by using anodal transcranial direct current stimulation (tDCS). In the present study, we aimed to monitor cortical excitability changes during an implicit motor learning paradigm, a version of the serial reaction time task (SRTT). Responses from the first dorsal interosseous (FDI) and forearm flexor (FLEX) muscles were recorded before, during and after the performance of the SRTT. Online measurements were combined with anodal, cathodal or sham tDCS for the duration of the SRTT. Negative correlations between the amplitude of online FDI MEPs and SRTT reaction times (RTs) were observed across the learning blocks in the cathodal condition (higher average MEP amplitudes associated with lower RTs) but no significant differences in the anodal and sham conditions. tDCS did not have an impact on SRTT performance, as would be predicted based on previous studies. The offline before-after SRTT MEP amplitudes showed an increase after anodal and a tendency to decrease after cathodal stimulation, but these changes were not significant. The combination of different interventions during tDCS might result in reduced efficacy of the stimulation that in future studies need further attention. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  18. Ground penetrating radar and direct current resistivity evaluation of the desiccation test cap, Savannah River Site

    Wyatt, D.E.; Cumbest, R.J.

    1996-04-01

    The Savannah River Site (SRS) has a variety of waste units that may be temporarily or permanently stabilized by closure using an impermeable cover to prevent groundwater infiltration. The placement of an engineered kaolin clay layer over a waste unit is an accepted and economical technique for providing an impermeable cover but the long term stability and integrity of the clay in non-arid conditions is unknown. A simulated kaolin cap has been constructed at the SRA adjacent to the Burial Ground Complex. The cap is designed to evaluate the effects of desiccation on clay integrity, therefore half of the cap is covered with native soil to prevent drying, while the remainder of the cap is exposed. Measurements of the continuing impermeability of a clay cap are difficult because intrusive techniques may locally compromise the structure. Point measurements made to evaluate clay integrity, such as those from grid sampling or coring and made through a soil cover, may miss cracks, joints or fissures, and may not allow for mapping of the lateral extent of elongate features. Because of these problems, a non-invasive technique is needed to map clay integrity, below a soil or vegetation cover, which is capable of moderate to rapid investigation speeds. Two non-intrusive geophysical techniques, direct current resistivity and ground penetrating radar (GPR), have been successful at the SRS in geologically mapping shallow subsurface clay layers. The applicability of each technique in detecting the clay layer in the desiccation test cap and associated anomalies was investigated

  19. DI3 - A New Procedure for Absolute Directional Measurements

    A Geese

    2011-06-01

    Full Text Available The standard observatory procedure for determining a geomagnetic field's declination and inclination absolutely is the DI-flux measurement. The instrument consists of a non-magnetic theodolite equipped with a single-axis fluxgate magnetometer. Additionally, a scalar magnetometer is needed to provide all three components of the field. Using only 12 measurement steps, all systematic errors can be accounted for, but if only one of the readings is wrong, the whole measurement has to be rejected. We use a three-component sensor on top of the theodolites telescope. By performing more measurement steps, we gain much better control of the whole procedure: As the magnetometer can be fully calibrated by rotating about two independent directions, every combined reading of magnetometer output and theodolite angles provides the absolute field vector. We predefined a set of angle positions that the observer has to try to achieve. To further simplify the measurement procedure, the observer is guided by a pocket pc, in which he has only to confirm the theodolite position. The magnetic field is then stored automatically, together with the horizontal and vertical angles. The DI3 measurement is periodically performed at the Niemegk Observatory, allowing for a direct comparison with the traditional measurements.

  20. Directed Current Without Dissipation: Reincarnation of a Maxwell-Loschmidt Demon

    Goychuk, Igor; Haenggi, Peter

    We investigate whether for initially localized particles a directed current in rocked periodic structures is possible in absence of a dissipative mechanism. With a pure Hamiltonian dynamics the breaking of Time-Reversal-Invariante presents anecessary condition to find nonzero current values. Numerical studies are presented for the classical Hamiltonian dynamical case. These support the fact that indeed a finite current does occur when a time-reversal symmetry-breaking signal, such as a harmonic mixing signal, is acting. To gain analytical insight we consider the coherent driven quantum transport in a one-dimensional tight-binding lattice. Here, a finite coherent current is absent for initially localized preparations; it emerges, however, when the initial preparation (with zero initial current) possesses finite coherence. The presence of phase fluctuations will eventually kill any finite current, thereby rendering the nondissipative currents a transient phenomenon.

  1. Effects of an NMDA antagonist on the auditory mismatch negativity response to transcranial direct current stimulation.

    Impey, Danielle; de la Salle, Sara; Baddeley, Ashley; Knott, Verner

    2017-05-01

    Transcranial direct current stimulation (tDCS) is a non-invasive form of brain stimulation which uses a weak constant current to alter cortical excitability and activity temporarily. tDCS-induced increases in neuronal excitability and performance improvements have been observed following anodal stimulation of brain regions associated with visual and motor functions, but relatively little research has been conducted with respect to auditory processing. Recently, pilot study results indicate that anodal tDCS can increase auditory deviance detection, whereas cathodal tDCS decreases auditory processing, as measured by a brain-based event-related potential (ERP), mismatch negativity (MMN). As evidence has shown that tDCS lasting effects may be dependent on N-methyl-D-aspartate (NMDA) receptor activity, the current study investigated the use of dextromethorphan (DMO), an NMDA antagonist, to assess possible modulation of tDCS's effects on both MMN and working memory performance. The study, conducted in 12 healthy volunteers, involved four laboratory test sessions within a randomised, placebo and sham-controlled crossover design that compared pre- and post-anodal tDCS over the auditory cortex (2 mA for 20 minutes to excite cortical activity temporarily and locally) and sham stimulation (i.e. device is turned off) during both DMO (50 mL) and placebo administration. Anodal tDCS increased MMN amplitudes with placebo administration. Significant increases were not seen with sham stimulation or with anodal stimulation during DMO administration. With sham stimulation (i.e. no stimulation), DMO decreased MMN amplitudes. Findings from this study contribute to the understanding of underlying neurobiological mechanisms mediating tDCS sensory and memory improvements.

  2. Method for exciting inductive-resistive loads with high and controllable direct current

    Hill, H.M. Jr.

    1976-01-01

    The apparatus and method for transmitting dc power to a load circuit by applying a dc voltage from a standard waveform synthesizer to duration modulate a bipolar rectangular wave generator are described. As the amplitude of the dc voltage increases, the widths of the rectangular wave generator output pulses increase, and as the amplitude of the dc voltage decreases, the widths of the rectangular wave generator output pulses decrease. Thus, the waveform synthesizer selectively changes the durations of the rectangular wave generator bipolar output pulses so as to produce a rectangular wave ac carrier that is duration modulated in accordance with and in direct proportion to the voltage amplitude from the synthesizer. Thereupon, by transferring the carrier to the load circuit through an amplifier and a rectifier, the load current also corresponds directly to the voltage amplitude from the synthesizer. To this end, the rectified wave at less than 100 percent duty factor amounts to a doubled frequency direct voltage pulse train for applying a direct current to the load, while the current ripple is minimized by a high L/R in the load circuit. In one embodiment, a power transmitting power amplifier means having a dc power supply is matched to the load circuit through a transformer for current magnification without sacrificing load current duration capability, while negative voltage and current feedback are provided in order to insure good output fidelity. 4 Claims, 18 Drawing Figures

  3. Co-ordination of directional overcurrent protection with load current for parallel feeders

    Wright, J.W.; Lloyd, G.; Hindle, P.J. [Alstom, Inc., Stafford (United Kingdom). T and D Protection and Control

    1999-11-01

    Directional phase overcurrent relays are commonly applied at the receiving ends of parallel feeders or transformer feeders. Their purpose is to ensure full discrimination of main or back-up power system overcurrent protection for a fault near the receiving end of one feeder. This paper reviews this type of relay application and highlights load current setting constraints for directional protection. Such constraints have not previously been publicized in well-known text books. A directional relay current setting constraint that is suggested in some text books is based purely on thermal rating considerations for older technology relays. This constraint may not exist with modern numerical relays. In the absence of any apparent constraint, there is a temptation to adopt lower current settings with modern directional relays in relation to reverse load current at the receiving ends of parallel feeders. This paper identifies the danger of adopting very low current settings without any special relay feature to ensure protection security with load current during power system faults. A system incident recorded by numerical relays is also offered to highlight this danger. In cases where there is a need to infringe the identified constraints an implemented and testing relaying technique is proposed.

  4. Polarity-Specific Transcranial Direct Current Stimulation Disrupts Auditory Pitch Learning

    Reiko eMatsushita

    2015-05-01

    Full Text Available Transcranial direct current stimulation (tDCS is attracting increasing interest because of its potential for therapeutic use. While its effects have been investigated mainly with motor and visual tasks, less is known in the auditory domain. Past tDCS studies with auditory tasks demonstrated various behavioural outcomes, possibly due to differences in stimulation parameters or task measurements used in each study. Further research using well-validated tasks are therefore required for clarification of behavioural effects of tDCS on the auditory system. Here, we took advantage of findings from a prior functional magnetic resonance imaging study, which demonstrated that the right auditory cortex is modulated during fine-grained pitch learning of microtonal melodic patterns. Targeting the right auditory cortex with tDCS using this same task thus allowed us to test the hypothesis that this region is causally involved in pitch learning. Participants in the current study were trained for three days while we measured pitch discrimination thresholds using microtonal melodies on each day using a psychophysical staircase procedure. We administered anodal, cathodal, or sham tDCS to three groups of participants over the right auditory cortex on the second day of training during performance of the task. Both the sham and the cathodal groups showed the expected significant learning effect (decreased pitch threshold over the three days of training; in contrast we observed a blocking effect of anodal tDCS on auditory pitch learning, such that this group showed no significant change in thresholds over the three days. The results support a causal role for the right auditory cortex in pitch discrimination learning.

  5. Effects of transcranial direct current stimulation (tDCS) on pain distress tolerance: a preliminary study

    Mariano, Timothy Y.; Wout, Mascha van’t; Jacobson, Benjamin L.; Garnaat, Sarah L.; Kirschner, Jason L.; Rasmussen, Steven A.; Greenberg, Benjamin D.

    2015-01-01

    Objective Pain remains a critical medical challenge. Current treatments target nociception without addressing affective symptoms. Medically intractable pain is sometimes treated with cingulotomy or deep brain stimulation to increase tolerance of pain-related distress. Transcranial direct current stimulation (tDCS) may noninvasively modulate cortical areas related to sensation and pain representations. The present study aimed to test the hypothesis that cathodal (“inhibitory”) stimulation targeting left dorsal anterior cingulate cortex (dACC) would increase tolerance to distress from acute painful stimuli versus anodal stimulation. Methods Forty healthy volunteers received both anodal and cathodal stimulation. During stimulation, we measured pain distress tolerance with three tasks: pressure algometer, cold pressor, and breath holding. We measured pain intensity with a visual-analog scale before and after each task. Results Mixed ANOVA revealed that mean cold pressor tolerance tended to be higher with cathodal versus anodal stimulation (p = 0.055) for participants self-completing the task. Pressure algometer (p = 0.81) and breath holding tolerance (p = 0.19) did not significantly differ. The pressure algometer exhibited a statistically significant order effect irrespective of stimulation polarity (all p Pain intensity ratings increased acutely after cold pressor and pressure algometer tasks (both p pain ratings tended to rise less after cathodal versus anodal tDCS (p = 0.072). Conclusions Although our primary results were nonsignificant, there is a preliminary suggestion that cathodal tDCS targeting left dACC may increase pain distress tolerance to cold pressor. Pressure algometer results are consistent with task-related sensitization. Future studies are needed to refine this novel approach for pain neuromodulation. PMID:26115372

  6. Method and system for a gas tube-based current source high voltage direct current transmission system

    She, Xu; Chokhawala, Rahul Shantilal; Bray, James William; Sommerer, Timothy John; Zhou, Rui; Zhang, Di

    2017-08-29

    A high-voltage direct-current (HVDC) transmission system includes an alternating current (AC) electrical source and a power converter channel that includes an AC-DC converter electrically coupled to the electrical source and a DC-AC inverter electrically coupled to the AC-DC converter. The AC-DC converter and the DC-AC inverter each include a plurality of legs that includes at least one switching device. The power converter channel further includes a commutating circuit communicatively coupled to one or more switching devices. The commutating circuit is configured to "switch on" one of the switching devices during a first portion of a cycle of the H-bridge switching circuits and "switch off" the switching device during a second portion of the cycle of the first and second H-bridge switching circuits.

  7. Inter- and Intra-individual Variability in Response to Transcranial Direct Current Stimulation (tDCS) at Varying Current Intensities.

    Chew, Taariq; Ho, Kerrie-Anne; Loo, Colleen K

    2015-01-01

    Translation of transcranial direct current stimulation (tDCS) from research to clinical practice is hindered by a lack of consensus on optimal stimulation parameters, significant inter-individual variability in response, and in sufficient intra-individual reliability data. Inter-individual differences in response to anodal tDCS at a range of current intensities were explored. Intra-individual reliability in response to anodal tDCS across two identical sessions was also investigated. Twenty-nine subjects participated in a crossover study. Anodal-tDCS using four different current intensities (0.2, 0.5, 1 and 2 mA), with an anode size of 16 cm2, was tested. The 0.5 mA condition was repeated to assess intra-individual variability. TMS was used to elicit 40 motor-evoked potentials (MEPs) before 10 min of tDCS, and 20 MEPs at four time-points over 30 min following tDCS. ANOVA revealed no main effect of TIME for all conditions except the first 0.5 mA condition, and no differences in response between the four current intensities. Cluster analysis identified two clusters for the 0.2 and 2 mA conditions only. Frequency distributions based on individual subject responses (excitatory, inhibitory or no response) to each condition indicate possible differential responses between individuals to different current intensities. Test-retest reliability was negligible (ICC(2,1) = -0.50). Significant inter-individual variability in response to tDCS across a range of current intensities was found. 2 mA and 0.2 mA tDCS were most effective at inducing a distinct response. Significant intra-individual variability in response to tDCS was also found. This has implications for interpreting results of single-session tDCS experiments. Crown Copyright © 2015. Published by Elsevier Inc. All rights reserved.

  8. Instrumentation for Gate Current Noise Measurements on sub-100 nm MOS Transistors

    Gaioni, L; Ratti, L; Re, V; Speziali, V; Traversi, G

    2008-01-01

    This work describes a measuring system that was developed to characterize the gate current noise performances of CMOS devices with minimum feature size in the 100 nm span. These devices play an essential role in the design of present daymixedsignal integrated circuits, because of the advantages associated with the scaling process. The reduction in the gate oxide thickness brought about by CMOS technology downscaling leads to a non-negligible gate current due to direct tunneling phenomena; this current represents a noise source which requires an accurate characterization for optimum analog design. In this paper, two instruments able to perform measurements in two different ranges of gate current values will be discussed. Some of the results of gate current noise characterization will also be presented.

  9. Modelling the effect of electrode displacement on transcranial direct current stimulation (tDCS)

    Ramaraju, Sriharsha; Roula, Mohammed A.; McCarthy, Peter W.

    2018-02-01

    Objective. Transcranial direct current stimulation (tDCS) is a neuromodulatory technique that delivers a low-intensity, direct current to cortical areas with the purpose of modulating underlying brain activity. Recent studies have reported inconsistencies in tDCS outcomes. The underlying assumption of many tDCS studies has been that replication of electrode montage equates to replicating stimulation conditions. It is possible however that anatomical difference between subjects, as well as inherent inaccuracies in montage placement, could affect current flow to targeted areas. The hypothesis that stimulation of a defined brain region will be stable under small displacements was tested. Approach. Initially, we compared the total simulated current flowing through ten specific brain areas for four commonly used tDCS montages: F3-Fp2, C3-Fp2, Fp1-F4, and P3-P4 using the software tool COMETS. The effect of a slight (~1 cm in each of four directions) anode displacement on the simulated regional current density for each of the four tDCS montages was then determined. Current flow was calculated and compared through ten segmented brain areas to determine the effect of montage type and displacement. The regional currents, as well as the localised current densities, were compared with the original electrode location, for each of these new positions. Main results. Recommendations for montages that maximise stimulation current for the ten brain regions are considered. We noted that the extent to which stimulation is affected by electrode displacement varies depending on both area and montage type. The F3-Fp2 montage was found to be the least stable with up to 38% change in average current density in the left frontal lobe while the Fp1-F4 montage was found to the most stable exhibiting only 1% change when electrodes were displaced. Significance. These results indicate that even relatively small changes in stimulation electrode placement appear to result in surprisingly large

  10. High-temperature performance of MoS{sub 2} thin-film transistors: Direct current and pulse current-voltage characteristics

    Jiang, C.; Samnakay, R.; Balandin, A. A., E-mail: balandin@ee.ucr.edu [Nano-Device Laboratory (NDL), Department of Electrical Engineering, Bourns College of Engineering, University of California—Riverside, Riverside, California 92521 (United States); Phonon Optimized Engineered Materials (POEM) Center, Materials Science and Engineering Program, University of California—Riverside, Riverside, California 92521 (United States); Rumyantsev, S. L. [Department of Electrical, Computer, and Systems Engineering, Center for Integrated Electronics, Rensselaer Polytechnic Institute, Troy, New York 12180 (United States); Ioffe Physical-Technical Institute, St. Petersburg 194021 (Russian Federation); Shur, M. S. [Department of Electrical, Computer, and Systems Engineering, Center for Integrated Electronics, Rensselaer Polytechnic Institute, Troy, New York 12180 (United States)

    2015-02-14

    We report on fabrication of MoS{sub 2} thin-film transistors (TFTs) and experimental investigations of their high-temperature current-voltage characteristics. The measurements show that MoS{sub 2} devices remain functional to temperatures of at least as high as 500 K. The temperature increase results in decreased threshold voltage and mobility. The comparison of the direct current (DC) and pulse measurements shows that the direct current sub-linear and super-linear output characteristics of MoS{sub 2} thin-films devices result from the Joule heating and the interplay of the threshold voltage and mobility temperature dependences. At temperatures above 450 K, a kink in the drain current occurs at zero gate voltage irrespective of the threshold voltage value. This intriguing phenomenon, referred to as a “memory step,” was attributed to the slow relaxation processes in thin films similar to those in graphene and electron glasses. The fabricated MoS{sub 2} thin-film transistors demonstrated stable operation after two months of aging. The obtained results suggest new applications for MoS{sub 2} thin-film transistors in extreme-temperature electronics and sensors.

  11. Feedwater flow measurements: challenges, current solutions, and 'soft' developments

    Ruan, D.; Roverso, D.; Fantoni, P.F.; Sanabrias, J.I.; Carrasco, J.A.; Fernandez, L.

    2002-07-01

    This report presents an early progress of a feasibility study of a computational intelligence approach to the enhancement of the accuracy of feedwater flow measurements in the framework of an ongoing cooperation between Tecnatom s.a. in Madrid and the OECD Halden Reactor Project (HRP) in Halden. The aim of this research project is to contribute to the development and validation of a flow sensor in a nuclear power plant (NPP). The basic idea is to combine the use of applied computational intelligence approaches (noise analysis, neural networks, fuzzy systems, wavelets etc.) with existing traditional flow measurements, and in particular with cross correlation flow meter concepts. In this report, Section 2 outlines relevant aspects of thermal power calculations on electrical power plants. Section 3 reviews from the available literature possible approaches and solutions for feedwater flow measurement, including ultrasonic flow meters, cross-correlation flow meters, and 'Virtural' flow meters with artificial neural networks. Section 4 reports typical experimental measurements at the Tecnatom's facility. Section 5 presents an integration approach and preliminary experimental tests. Section 6 discusses the role of soft computing techniques in the context of feedwater flow measurements related nuclear fields, and Section 7 highlights the future research direction. (Author)

  12. Nearshore Processes, Currents and Directional Wave Spectra Monitoring Using Coherent and Non-coherent Imaging Radars

    Trizna, D.; Hathaway, K.

    2007-05-01

    Two new radar systems have been developed for real-time measurement of near-shore processes, and results are presented for measurements of ocean wave spectra, near-shore sand bar structure, and ocean currents. The first is a non-coherent radar based on a modified version of the Sitex radar family, with a data acquisition system designed around an ISR digital receiver card. The card operates in a PC computer with inputs from a Sitex radar modified for extraction of analogue signals for digitization. Using a 9' antenna and 25 kW transmit power system, data were collected during 2007 at the U.S. Army Corps of Engineers Field Research Facility (FRF), Duck, NC during winter and spring of 2007. The directional wave spectrum measurements made are based on using a sequence of 64 to 640 antenna rotations to form a snapshot series of radar images of propagating waves. A square window is extracted from each image, typically 64 x 64 pixels at 3-m resolution. Then ten sets of 64 windows are submitted to a three-dimensional Fast Fourier Transform process to generate radar image spectra in the frequency-wavenumber space. The relation between the radar image spectral intensity and wave spectral intensity derived from the FRF pressure gauge array was used for a test set of data, in order to establish a modulation transfer function (MTF) for each frequency component. For 640 rotations, 10 of such spectra are averaged for improved statistics. The wave spectrum so generated was compared for extended data sets beyond those used to establish the MTF, and those results are presented here. Some differences between the radar and pressure sensor data that are observed are found to be due to the influence of the wind field, as the radar echo image weakens for light winds. A model is developed to account for such an effect to improve the radar estimate of the directional wave spectrum. The radar ocean wave imagery is severely influenced only by extremely heavy rain-fall rates, so that

  13. Current direction, benthic organisms, temperature, and wind direction data from moored current meter casts in the Gulf of Mexico during the Brine Disposal project, 22 September 1977 - 30 November 1978 (NODC Accession 7900110)

    National Oceanic and Atmospheric Administration, Department of Commerce — Current direction, benthic organisms, temperature, and wind direction data were collected using moored current meter casts in the Gulf of Mexico from September 22,...

  14. Wind direction/velocity and current direction/velocity data from current meter casts in a world wide distribution from 1970-12-06 to 1991-10-01 (NODC Accession 9700218)

    National Oceanic and Atmospheric Administration, Department of Commerce — Wind direction/velocity and current direction/velocity data were collected using current meter casts in a world wide distribution from December 6, 1970 to October 1,...

  15. Current direction, wind direction, temperature, and salinity data from moored current meter casts in the Gulf of Mexico during the Brine Disposal project, 01 February 1981 - 01 February 1981 (NODC Accession 8100516)

    National Oceanic and Atmospheric Administration, Department of Commerce — Current direction, temperature, wind direction, and salinity data were collected using moored current meter casts in the Gulf of Mexico from February 1, 1981 to...

  16. Direct shaft torque measurements in a transient turbine facility

    Beard, Paul F; Povey, Thomas

    2011-01-01

    This paper describes the development and implementation of a shaft torque measurement system for the Oxford Turbine Research Facility (formerly the Turbine Test Facility (TTF) at QinetiQ, Farnborough), or OTRF. As part of the recent EU TATEF II programme, the facility was upgraded to allow turbine efficiency measurements to be performed. A shaft torque measurement system was developed as part of this upgrade. The system is unique in that, to the authors' knowledge, it provided the first direct measurement of shaft torque in a transient turbine facility although the system has wider applicability to rotating test facilities in which power measurement is a requirement. The adopted approach removes the requirement to quantify bearing friction, which can be difficult to accurately calibrate under representative operating conditions. The OTRF is a short duration (approximately 0.4 s run time) isentropic light-piston facility capable of matching all of the non-dimensional parameters important for aerodynamic and heat studies, namely Mach number, Reynolds number, non-dimensional speed, stage pressure ratio and gas-to-wall temperature ratio. The single-stage MT1 turbine used for this study is a highly loaded unshrouded design, and as such is relevant to modern military, or future civil aero-engine design. Shaft torque was measured directly using a custom-built strain gauge-based torque measurement system in the rotating frame of reference. This paper describes the development of this measurement system. The system was calibrated, including the effects of temperature, to a traceable primary standard using a purpose-built facility. The bias and precision uncertainties of the measured torque were ±0.117% and ±0.183%, respectively. To accurately determine the shaft torque developed by a turbine in the OTRF, small corrections due to inertial torque (associated with changes in the rotational speed) and aerodynamic drag (windage) are required. The methods for performing these

  17. Analysis of critical thinking ability in direct current electrical problems solving

    Hartono; Sunarno, Widha; Sarwanto; Arya Nugraha, Dewanta

    2017-11-01

    This study concern on analyzing the ability of students in critical thinking skills on the subject matter of direct current electricity. Samples were taken using purposive random sampling consisted of 32 students of grade XI, Multimedia 1, SMK Negeri 3 Surakarta in academic year 2016/2017. This study used descriptive quantitative method. The data were collected using tests and interviews regarding the subject matter of direct current electricity. Based on the results, students are getting some difficulties in solving problem in indicator 4. The average of students’ correct answer is 62.8%.

  18. Non-Cyanide Electrodeposited Ag–PTFE Composite Coating Using Direct or Pulsed Current Deposition

    Raymond Sieh

    2016-07-01

    Full Text Available The effects of FC-4 cationic surfactant on electrodeposited Ag–PTFE composite coating using direct or pulsed currents were studied using scanning electron microscope (SEM, energy dispersive X-ray (EDS, optical microscope, and a linear tribometer. FC-4:PTFE in various ratios were added to a non-cyanide succinimide silver complex bath. Direct or pulsed current method was used at a constant current density to enable comparison between both methods. A high incorporation rate of PTFE was successfully achieved, with pulsed current being highly useful in increasing the amount of PTFE in the composite coating. The study of coating wear under sliding showed that a large majority of the electrodeposited coatings still managed to adhere to the substrate, even after 10 wear cycles of sliding tests. Performance improvements were achieved on all the samples with a coefficient of friction (CoF between 0.06 and 0.12.

  19. Direct measurements of transport properties are essential for site characterization

    Wright, J.; Conca, J.L.

    1994-08-01

    Direct measurements of transport parameters on subsurface sediments using, the UFA method provided detailed hydrostratigraphic mapping, and subsurface flux distributions at a mixed-waste disposal site at Hanford. Seven hundred unsaturated conductivity measurements on fifty samples were obtained in only six months total of UFA run time. These data are used to provide realistic information to conceptual models, predictive models and restoration strategies. The UFA instrument consists of an ultracentrifuge with a constant, ultralow flow pump that provides fluid to the sample surface through a rotating seal assembly and microdispersal system. Effluent from the sample is collected in a transparent, volumetrically-calibrated chamber at the bottom of the sample assembly. Using a strobe light, an observer can check the chamber while the sample is being centrifuged. Materials can be run in the UFA as recomposited samples or in situ samples can be subcored directly into the sample UFA chamber

  20. Transcranial direct-current stimulation induced in stroke patients with aphasia: a prospective experimental cohort study

    Michele Devido Santos

    Full Text Available CONTEXT AND OBJECTIVE: Previous animal and human studies have shown that transcranial direct current stimulation can induce significant and lasting neuroplasticity and may improve language recovery in patients with aphasia. The objective of the study was to describe a cohort of patients with aphasia after stroke who were treated with transcranial direct current stimulation. DESIGN AND SETTING: Prospective cohort study developed in a public university hospital. METHODS: Nineteen patients with chronic aphasia received 10 transcranial direct current stimulation sessions lasting 20 minutes each on consecutive days, using a current of 2 mA. The anode was positioned over the supraorbital area and the cathode over the contralateral motor cortex. The following variables were analyzed before and after the 10 neuromodulation sessions: oral language comprehension, copying, dictation, reading, writing, naming and verbal fluency. RESULTS: There were no adverse effects in the study. We found statistically significant differences from before to after stimulation in relation to simple sentence comprehension (P = 0.034, naming (P = 0.041 and verbal fluency for names of animals (P = 0.038. Improved scores for performing these three tasks were seen after stimulation. CONCLUSIONS: We observed that excitability of the primary motor cortex through transcranial direct current stimulation was associated with effects on different aspects of language. This can contribute towards future testing in randomized controlled trials.

  1. Transcranial direct-current stimulation induced in stroke patients with aphasia: a prospective experimental cohort study.

    Santos, Michele Devido; Gagliardi, Rubens José; Mac-Kay, Ana Paula Machado Goyano; Boggio, Paulo Sergio; Lianza, Roberta; Fregni, Felipe

    2013-01-01

    Previous animal and human studies have shown that transcranial direct current stimulation can induce significant and lasting neuroplasticity and may improve language recovery in patients with aphasia. The objective of the study was to describe a cohort of patients with aphasia after stroke who were treated with transcranial direct current stimulation. Prospective cohort study developed in a public university hospital. Nineteen patients with chronic aphasia received 10 transcranial direct current stimulation sessions lasting 20 minutes each on consecutive days, using a current of 2 mA. The anode was positioned over the supraorbital area and the cathode over the contralateral motor cortex. The following variables were analyzed before and after the 10 neuromodulation sessions: oral language comprehension, copying, dictation, reading, writing, naming and verbal fluency. There were no adverse effects in the study. We found statistically significant differences from before to after stimulation in relation to simple sentence comprehension (P = 0.034), naming (P = 0.041) and verbal fluency for names of animals (P = 0.038). Improved scores for performing these three tasks were seen after stimulation. We observed that excitability of the primary motor cortex through transcranial direct current stimulation was associated with effects on different aspects of language. This can contribute towards future testing in randomized controlled trials.

  2. Detecting Single-Nucleotides by Tunneling Current Measurements at Sub-MHz Temporal Resolution.

    Morikawa, Takanori; Yokota, Kazumichi; Tanimoto, Sachie; Tsutsui, Makusu; Taniguchi, Masateru

    2017-04-18

    Label-free detection of single-nucleotides was performed by fast tunneling current measurements in a polar solvent at 1 MHz sampling rate using SiO₂-protected Au nanoprobes. Short current spikes were observed, suggestive of trapping/detrapping of individual nucleotides between the nanoelectrodes. The fall and rise features of the electrical signatures indicated signal retardation by capacitance effects with a time constant of about 10 microseconds. The high temporal resolution revealed current fluctuations, reflecting the molecular conformation degrees of freedom in the electrode gap. The method presented in this work may enable direct characterizations of dynamic changes in single-molecule conformations in an electrode gap in liquid.

  3. Effects of Transcranial Direct Current Stimulation (tDCS) on Human Memory.

    Matzen, Laura E.; Trumbo, Michael Christopher Stefan

    2014-10-01

    Training a person in a new knowledge base or skill set is extremely time consuming and costly, particularly in highly specialized domains such as the military and the intelligence community. Recent research in cognitive neuroscience has suggested that a technique called transcranial direct current stimulation (tDCS) has the potential to revolutionize training by enabling learners to acquire new skills faster, more efficiently, and more robustly (Bullard et al., 2011). In this project, we tested the effects of tDCS on two types of memory performance that are critical for learning new skills: associative memory and working memory. Associative memory is memory for the relationship between two items or events. It forms the foundation of all episodic memories, so enhancing associative memory could provide substantial benefits to the speed and robustness of learning new information. We tested the effects of tDCS on associative memory, using a real-world associative memory task: remembering the links between faces and names. Working memory refers to the amount of information that can be held in mind and processed at one time, and it forms the basis for all higher-level cognitive processing. We investigated the degree of transfer between various working memory tasks (the N-back task as a measure of verbal working memory, the rotation-span task as a measure of visuospatial working memory, and Raven's progressive matrices as a measure of fluid intelligence) in order to determine if tDCS-induced facilitation of performance is task-specific or general.

  4. Direct measurement of skin friction with a new instrument

    Vakili, A. D.; Wu, J. M.

    1986-01-01

    The design and performance of a small belt-type skin-friction gage to measure wall shear-stress coefficients in wind-tunnel testing are described, summarizing the report of Vakili and Wu (1982). The sensor employs a flexible belt of variable surface characteristics; this belt, wrapped tightly around two cylinders mounted on frictionless flexures, is equipped with strain gages to estimate the deflection of the belt by the flow. An alternative approach uses IR illumination, optical fibers, and a photosensitive transistor, permitting direct measurement of the belt deflection. Drawings, diagrams, and graphs of sample data are provided.

  5. Direct nn-Scattering Measurement With the Pulsed Reactor YAGUAR.

    Mitchell, G E; Furman, W I; Lychagin, E V; Muzichka, A Yu; Nekhaev, G V; Strelkov, A V; Sharapov, E I; Shvetsov, V N; Chernuhin, Yu I; Levakov, B G; Litvin, V I; Lyzhin, A E; Magda, E P; Crawford, B E; Stephenson, S L; Howell, C R; Tornow, W

    2005-01-01

    Although crucial for resolving the issue of charge symmetry in the nuclear force, direct measurement of nn-scattering by colliding free neutrons has never been performed. At present the Russian pulsed reactor YAGUAR is the best neutron source for performing such a measurement. It has a through channel where the neutron moderator is installed. The neutrons are counted by a neutron detector located 12 m from the reactor. In preliminary experiments an instantaneous value of 1.1 × 10(18)/cm(2)s was obtained for the thermal neutron flux density. The experiment will be performed by the DIANNA Collaboration as International Science & Technology Center (ISTC) project No. 2286.

  6. Radar velocity determination using direction of arrival measurements

    Doerry, Armin W.; Bickel, Douglas L.; Naething, Richard M.; Horndt, Volker

    2017-12-19

    The various technologies presented herein relate to utilizing direction of arrival (DOA) data to determine various flight parameters for an aircraft A plurality of radar images (e.g., SAR images) can be analyzed to identify a plurality of pixels in the radar images relating to one or more ground targets. In an embodiment, the plurality of pixels can be selected based upon the pixels exceeding a SNR threshold. The DOA data in conjunction with a measurable Doppler frequency for each pixel can be obtained. Multi-aperture technology enables derivation of an independent measure of DOA to each pixel based on interferometric analysis. This independent measure of DOA enables decoupling of the aircraft velocity from the DOA in a range-Doppler map, thereby enabling determination of a radar velocity. The determined aircraft velocity can be utilized to update an onboard INS, and to keep it aligned, without the need for additional velocity-measuring instrumentation.

  7. Transportable IOT measurement station for direct-broadcast satellites

    Ulbricht, Michael

    A transportable 11.7-12.5-GHz flux-density measurement facility for use in the in-orbit testing (IOT) of the FRG TV-Sat direct-broadcast satellites is described. Major components include a 1.2-m-diameter antenna, the fluxmeter, a radiometer to determine atmospheric attenuation, a weather station, and a control and data-processing computer; all of the components are mounted on a 5.10 x 2.35 x 2.70-m trailer. IOT performance parameters include gain/temperature ratio 15.9 dB/K, measurement range -97 to -117 dBW/sq m, measurement accuracy less than 0.5 dB rms, and measurement rate 250-650 msec. Photographs and a block diagram are provided.

  8. Development of an intelligent high-voltage direct-current power supply for nuclear detectors

    Zhao Xiuliang

    1997-01-01

    The operation and performances of a new type direct-current high-voltage power supply are described. The power supply with intelligent feature is controlled by a single-chip microcomputer (8031), and various kinds of output voltage can be preset. The output-voltage is monitored and regulated by the single-chip microcomputer and displayed by LED. The output voltage is stable when the load current is within the allowable limits

  9. Eddy-current flow rate meter for measuring sodium flow rates

    Knaak, J.

    1976-01-01

    For safety reasons flow rate meters for monitoring coolant flow rates are inserted in the core of sodium-cooled fast breeder reactors. These are so-called eddy-current flow rate meters which can be mounted directly above the fuel elements. In the present contribution the principle of measurement, the mechanical construction and the circuit design of the flow rate measuring device are described. Special problems and their solution on developing the measuring system are pointed out. Finally, results of measurement and experience with the apparatus in several experiments are reported, where also further possibilities of application were tested. (orig./TK) [de

  10. Direct Measurement of the Surface Energy of Graphene.

    van Engers, Christian D; Cousens, Nico E A; Babenko, Vitaliy; Britton, Jude; Zappone, Bruno; Grobert, Nicole; Perkin, Susan

    2017-06-14

    Graphene produced by chemical vapor deposition (CVD) is a promising candidate for implementing graphene in a range of technologies. In most device configurations, one side of the graphene is supported by a solid substrate, wheras the other side is in contact with a medium of interest, such as a liquid or other two-dimensional material within a van der Waals stack. In such devices, graphene interacts on both faces via noncovalent interactions and therefore surface energies are key parameters for device fabrication and operation. In this work, we directly measured adhesive forces and surface energies of CVD-grown graphene in dry nitrogen, water, and sodium cholate using a modified surface force balance. For this, we fabricated large (∼1 cm 2 ) and clean graphene-coated surfaces with smooth topography at both macro- and nanoscales. By bringing two such surfaces into contact and measuring the force required to separate them, we measured the surface energy of single-layer graphene in dry nitrogen to be 115 ± 4 mJ/m 2 , which was similar to that of few-layer graphene (119 ± 3 mJ/m 2 ). In water and sodium cholate, we measured interfacial energies of 83 ± 7 and 29 ± 6 mJ/m 2 , respectively. Our work provides the first direct measurement of graphene surface energy and is expected to have an impact both on the development of graphene-based devices and contribute to the fundamental understanding of surface interactions.

  11. Poloidal polarimeter for current density measurements in ITER

    Donne, A.J.H.; Graswinckel, M.F.; Cavinato, M.; Giudicotti, L.; Zilli, E.; Gil, C.; Koslowski, H.R.; McCarthy, P.; Nyhan, C.; Prunty, S.; Spillane, M.; Walker, C.

    2004-01-01

    One of the systems envisaged for measuring the current density profile in the ITER is a 118 μm poloidal polarimeter system. The proposed system has two independent views: one fan of chords observes the plasma via an equatorial port and a second fan views down from an upper port. This article will present the status of the on-going work and will address issues as sensitivity and accuracy, refraction, Gaussian beam ray-tracing, alignment, and calibration as well as some specific design details

  12. Model for an irreversible bias current in the superconducting qubit measurement process

    Hutchinson, G. D.; Williams, D. A.; Holmes, C. A.; Stace, T. M.; Spiller, T. P.; Barrett, S. D.; Milburn, G. J.; Hasko, D. G.

    2006-01-01

    The superconducting charge-phase ''quantronium'' qubit is considered in order to develop a model for the measurement process used in the experiment of Vion et al. [Science 296, 886 (2002)]. For this model we propose a method for including the bias current in the readout process in a fundamentally irreversible way, which to first order is approximated by the Josephson junction tilted-washboard potential phenomenology. The decohering bias current is introduced in the form of a Lindblad operator and the Wigner function for the current-biased readout Josephson junction is derived and analyzed. During the readout current pulse used in the quantronium experiment we find that the coherence of the qubit initially prepared in a symmetric superposition state is lost at a time of 0.2 ns after the bias current pulse has been applied, a time scale that is much shorter than the experimental readout time. Additionally we look at the effect of Johnson-Nyquist noise with zero mean from the current source during the qubit manipulation and show that the decoherence due to the irreversible bias current description is an order of magnitude smaller than that found through adding noise to the reversible tilted-washboard potential model. Our irreversible bias current model is also applicable to persistent-current-based qubits where the state is measured according to its flux via a small-inductance direct-current superconducting quantum interference device

  13. Safety and tolerability of transcranial direct current stimulation to stroke patients - A phase I current escalation study.

    Chhatbar, Pratik Y; Chen, Rong; Deardorff, Rachael; Dellenbach, Blair; Kautz, Steven A; George, Mark S; Feng, Wuwei

    A prior meta-analysis revealed that higher doses of transcranial direct current stimulation (tDCS) have a better post-stroke upper-extremity motor recovery. While this finding suggests that currents greater than the typically used 2 mA may be more efficacious, the safety and tolerability of higher currents have not been assessed in stroke patients. We aim to assess the safety and tolerability of single session of up to 4 mA in stroke patients. We adapted a traditional 3 + 3 study design with a current escalation schedule of 1»2»2.5»3»3.5»4 mA for this tDCS safety study. We administered one 30-min session of bihemispheric montage tDCS and simultaneous customary occupational therapy to patients with first-ever ischemic stroke. We assessed safety with pre-defined stopping rules and investigated tolerability through a questionnaire. Additionally, we monitored body resistance and skin temperature in real-time at the electrode contact site. Eighteen patients completed the study. The current was escalated to 4 mA without meeting the pre-defined stopping rules or causing any major safety concern. 50% of patients experienced transient skin redness without injury. No rise in temperature (range 26°C-35 °C) was noted and skin barrier function remained intact (i.e. body resistance >1 kΩ). Our phase I safety study supports that single session of bihemispheric tDCS with current up to 4 mA is safe and tolerable in stroke patients. A phase II study to further test the safety and preliminary efficacy with multi-session tDCS at 4 mA (as compared with lower current and sham stimulation) is a logical next step. ClinicalTrials.gov Identifier: NCT02763826. Copyright © 2017 Elsevier Inc. All rights reserved.

  14. Onsite-effects of dual-hemisphere versus conventional single-hemisphere transcranial direct current stimulation: A functional MRI study.

    Kwon, Yong Hyun; Jang, Sung Ho

    2012-08-25

    We performed functional MRI examinations in six right-handed healthy subjects. During functional MRI scanning, transcranial direct current stimulation was delivered with the anode over the right primary sensorimotor cortex and the cathode over the left primary sensorimotor cortex using dual-hemispheric transcranial direct current stimulation. This was compared to a cathode over the left supraorbital area using conventional single-hemispheric transcranial direct current stimulation. Voxel counts and blood oxygenation level-dependent signal intensities in the right primary sensorimotor cortex regions were estimated and compared between the two transcranial direct current stimulation conditions. Our results showed that dual-hemispheric transcranial direct current stimulation induced greater cortical activities than single-hemispheric transcranial direct current stimulation. These findings suggest that dual-hemispheric transcranial direct current stimulation may provide more effective cortical stimulation than single-hemispheric transcranial direct current stimulation.

  15. An Annotated Bibliography of High-Voltage Direct-Current Transmission and Flexible AC Transmission (FACTS) Devices, 1991-1993.

    Litzenberger, Wayne; Lava, Val

    1994-08-01

    References are contained for HVDC systems, converter stations and components, overhead transmission lines, cable transmission, system design and operations, simulation of high voltage direct current systems, high-voltage direct current installations, and flexible AC transmission system (FACTS).

  16. Comparison of direct and alternating current vacuum ultraviolet lamps in atmospheric pressure photoionization.

    Vaikkinen, Anu; Haapala, Markus; Kersten, Hendrik; Benter, Thorsten; Kostiainen, Risto; Kauppila, Tiina J

    2012-02-07

    A direct current induced vacuum ultraviolet (dc-VUV) krypton discharge lamp and an alternating current, radio frequency (rf) induced VUV lamp that are essentially similar to lamps in commercial atmospheric pressure photoionization (APPI) ion sources were compared. The emission distributions along the diameter of the lamp exit window were measured, and they showed that the beam of the rf lamp is much wider than that of the dc lamp. Thus, the rf lamp has larger efficient ionization area, and it also emits more photons than the dc lamp. The ionization efficiencies of the lamps were compared using identical spray geometries with both lamps in microchip APPI mass spectrometry (μAPPI-MS) and desorption atmospheric pressure photoionization-mass spectrometry (DAPPI-MS). A comprehensive view on the ionization was gained by studying six different μAPPI solvent compositions, five DAPPI spray solvents, and completely solvent-free DAPPI. The observed reactant ions for each solvent composition were very similar with both lamps except for toluene, which showed a higher amount of solvent originating oxidation products with the rf lamp than with the dc lamp in μAPPI. Moreover, the same analyte ions were detected with both lamps, and thus, the ionization mechanisms with both lamps are similar. The rf lamp showed a higher ionization efficiency than the dc lamp in all experiments. The difference between the lamp ionization efficiencies was greatest when high ionization energy (IE) solvent compositions (IEs above 10 eV), i.e., hexane, methanol, and methanol/water, (1:1 v:v) were used. The higher ionization efficiency of the rf lamp is likely due to the larger area of high intensity light emission, and the resulting larger efficient ionization area and higher amount of photons emitted. These result in higher solvent reactant ion production, which in turn enables more efficient analyte ion production. © 2012 American Chemical Society

  17. Optical emission spectroscopy diagnostics of an atmospheric pressure direct current microplasma jet

    Sismanoglu, B.N., E-mail: bogos@ita.b [Departamento de Fisica, Instituto Tecnologico de Aeronautica, Comando-Geral de Tecnologia Aeroespacial, Pca Marechal Eduardo Gomes 50, 12 228-900, Sao Jose dos Campos, SP (Brazil); Amorim, J., E-mail: jayr.amorim@bioetanol.org.b [Centro de Ciencia e Tecnologia do Bioetanol - CTBE, Caixa Postal 6170, 13083-970 Campinas, Sao Paulo (Brazil); Souza-Correa, J.A., E-mail: jorge.correa@bioetanol.org.b [Centro de Ciencia e Tecnologia do Bioetanol - CTBE, Caixa Postal 6170, 13083-970 Campinas, Sao Paulo (Brazil); Oliveira, C., E-mail: carlosf@ita.b [Departamento de Fisica, Instituto Tecnologico de Aeronautica, Comando-Geral de Tecnologia Aeroespacial, Pca Marechal Eduardo Gomes 50, 12 228-900, Sao Jose dos Campos, SP (Brazil); Gomes, M.P., E-mail: gomesmp@ita.b [Departamento de Fisica, Instituto Tecnologico de Aeronautica, Comando-Geral de Tecnologia Aeroespacial, Pca Marechal Eduardo Gomes 50, 12 228-900, Sao Jose dos Campos, SP (Brazil)

    2009-11-15

    This paper is about the use of optical emission spectroscopy as a diagnostic tool to determine the gas discharge parameters of a direct current (98% Ar-2% H{sub 2}) non-thermal microplasma jet, operated at atmospheric pressure. The electrical and optical behaviors were studied to characterize this glow discharge. The microplasma jet was investigated in the normal and abnormal glow regimes, for current ranging from 10 to 130 mA, at approx 220 V of applied voltage for copper cathode. OH (A {sup 2}SIGMA{sup +}, nu = 0 -> X {sup 2}PI, nu' = 0) rotational bands at 306.357 nm and also the 603.213 nm Ar I line, which is sensitive to van der Waals broadening, were used to determine the gas temperature, which ranges from 550 to 800 K. The electron number densities, ranging from 6.0 x 10{sup 14} to 1.4 x 10{sup 15} cm{sup -3}, were determined through a careful analysis of the main broadening mechanisms of the H{sub beta} line. From both 603.213 nm and 565.070 nm Ar I line broadenings, it was possible to obtain simultaneously electron number density and temperature (approx 8000 K). Excitation temperatures were also measured from two methods: from two Cu I lines and from Boltzmann-plot of 4p-4s and 5p-4s Ar I transitions. By employing H{sub alpha} line, the hydrogen atoms' H temperature was estimated (approx 18,000 K) and found to be surprisingly hotter than the excitation temperature.

  18. Determination of optimal electrode positions for transcranial direct current stimulation (tDCS)

    Im, Chang-Hwan; Jung, Hui-Hun; Choi, Jung-Do; Lee, Soo Yeol; Jung, Ki-Young

    2008-01-01

    The present study introduces a new approach to determining optimal electrode positions in transcranial direct current stimulation (tDCS). Electric field and 3D conduction current density were analyzed using 3D finite element method (FEM) formulated for a dc conduction problem. The electrode positions for minimal current injection were optimized by changing the Cartesian coordinate system into the spherical coordinate system and applying the (2+6) evolution strategy (ES) algorithm. Preliminary simulation studies applied to a standard three-layer head model demonstrated that the proposed approach is promising in enhancing the performance of tDCS. (note)

  19. Determination of optimal electrode positions for transcranial direct current stimulation (tDCS)

    Im, Chang-Hwan; Jung, Hui-Hun; Choi, Jung-Do [Department of Biomedical Engineering, Yonsei University, Wonju, 220-710 (Korea, Republic of); Lee, Soo Yeol [Department of Biomedical Engineering, Kyung Hee University, Suwon (Korea, Republic of); Jung, Ki-Young [Korea University Medical Center, Korea University College of Medicine, Seoul (Korea, Republic of)], E-mail: ich@yonsei.ac.kr

    2008-06-07

    The present study introduces a new approach to determining optimal electrode positions in transcranial direct current stimulation (tDCS). Electric field and 3D conduction current density were analyzed using 3D finite element method (FEM) formulated for a dc conduction problem. The electrode positions for minimal current injection were optimized by changing the Cartesian coordinate system into the spherical coordinate system and applying the (2+6) evolution strategy (ES) algorithm. Preliminary simulation studies applied to a standard three-layer head model demonstrated that the proposed approach is promising in enhancing the performance of tDCS. (note)

  20. Load Torque Compensator for Model Predictive Direct Current Control in High Power PMSM Drive Systems

    Preindl, Matthias; Schaltz, Erik

    2010-01-01

    In drive systems the most used control structure is the cascade control with an inner torque, i.e. current and an outer speed control loop. The fairly small converter switching frequency in high power applications, e.g. wind turbines lead to modest speed control performance. An improvement bring...... the use of a current controller which takes into account the discrete states of the inverter, e.g. DTC or a more modern approach: Model Predictive Direct Current Control (MPDCC). Moreover overshoots and oscillations in the speed are not desired in many applications, since they lead to mechanical stress...

  1. Cytotoxicity, Bactericidal, and Antioxidant Activity of Sodium Alginate Hydrosols Treated with Direct Electric Current

    Żaneta Król

    2017-03-01

    Full Text Available The aim of the study was to investigate the effect of using direct electric current (DC of 0, 200, and 400 mA for five minutes on the physiochemical properties, cytotoxicity, antibacterial, and antioxidant activity of sodium alginate hydrosols with different sodium chloride concentrations. The pH, oxidation-reduction potential (ORP, electrical conductivity (EC, and available chlorine concentration (ACC were measured. The effect of sodium alginate hydrosols treated with DC on Staphylococcus aureus, Listeria monocytogenes, Bacillus cereus, Micrococcus luteus, Escherichia coli, Salmonella enteritidis, Yersinia enterocolitica, Pseudomonas fluorescence, and RAW 264.7 and L929 cells was investigated. Subsequently, the antioxidant properties of hydrosols were evaluated by determining the scavenging ability of 1,1-diphenyl-2-picrylhydrazyl free radical (DPPH and ferric reducing antioxidant power (FRAP. The results have shown that after applying 400 mA in hydrosol samples with 0.1% and 0.2% NaCl all tested bacteria were inactivated. The ACC concentration of C400 samples with NaCl was equal to 13.95 and 19.71 mg/L, respectively. The cytotoxicity analysis revealed that optimized electric field conditions and the addition of sodium chloride allow for the avoidance of toxicity effects on normal cells without disturbing the antibacterial effects. Due to the presence of oxidizing substances, the DPPH of variants treated with DC was lower than the DPPH of control samples.

  2. Modulation of motor performance and motor learning by transcranial direct current stimulation.

    Reis, Janine; Fritsch, Brita

    2011-12-01

    Transcranial direct current stimulation (tDCS) has shown preliminary success in improving motor performance and motor learning in healthy individuals, and restitution of motor deficits in stroke patients. This brief review highlights some recent work. Within the past years, behavioural studies have confirmed and specified the timing and polarity specific effects of tDCS on motor skill learning and motor adaptation. There is strong evidence that timely co-application of (hand/arm) training and anodal tDCS to the contralateral M1 can improve motor learning. Improvements in motor function as measured by clinical scores have been described for combined tDCS and training in stroke patients. For this purpose, electrode montages have been modified with respect to interhemispheric imbalance after brain injury. Cathodal tDCS applied to the unlesioned M1 or bihemispheric M1 stimulation appears to be well tolerated and useful to induce improvements in motor function. Mechanistic studies in humans and animals are discussed with regard to physiological motor learning. tDCS is well tolerated, easy to use and capable of inducing lasting improvements in motor function. This method holds promise for the rehabilitation of motor disabilities, although acute studies in patients with brain injury are so far lacking.

  3. Modulation of Total Sleep Time by Transcranial Direct Current Stimulation (tDCS).

    Frase, Lukas; Piosczyk, Hannah; Zittel, Sulamith; Jahn, Friederike; Selhausen, Peter; Krone, Lukas; Feige, Bernd; Mainberger, Florian; Maier, Jonathan G; Kuhn, Marion; Klöppel, Stefan; Normann, Claus; Sterr, Annette; Spiegelhalder, Kai; Riemann, Dieter; Nitsche, Michael A; Nissen, Christoph

    2016-09-01

    Arousal and sleep are fundamental physiological processes, and their modulation is of high clinical significance. This study tested the hypothesis that total sleep time (TST) in humans can be modulated by the non-invasive brain stimulation technique transcranial direct current stimulation (tDCS) targeting a 'top-down' cortico-thalamic pathway of sleep-wake regulation. Nineteen healthy participants underwent a within-subject, repeated-measures protocol across five nights in the sleep laboratory with polysomnographic monitoring (adaptation, baseline, three experimental nights). tDCS was delivered via bi-frontal target electrodes and bi-parietal return electrodes before sleep (anodal 'activation', cathodal 'deactivation', and sham stimulation). Bi-frontal anodal stimulation significantly decreased TST, compared with cathodal and sham stimulation. This effect was location specific. Bi-frontal cathodal stimulation did not significantly increase TST, potentially due to ceiling effects in good sleepers. Exploratory resting-state EEG analyses before and after the tDCS protocols were consistent with the notion of increased cortical arousal after anodal stimulation and decreased cortical arousal after cathodal stimulation. The study provides proof-of-concept that TST can be decreased by non-invasive bi-frontal anodal tDCS in healthy humans. Further elucidating the 'top-down' pathway of sleep-wake regulation is expected to increase knowledge on the fundamentals of sleep-wake regulation and to contribute to the development of novel treatments for clinical conditions of disturbed arousal and sleep.

  4. Impact of antipsychotic medication on transcranial direct current stimulation (tDCS) effects in schizophrenia patients.

    Agarwal, Sri Mahavir; Bose, Anushree; Shivakumar, Venkataram; Narayanaswamy, Janardhanan C; Chhabra, Harleen; Kalmady, Sunil V; Varambally, Shivarama; Nitsche, Michael A; Venkatasubramanian, Ganesan; Gangadhar, Bangalore N

    2016-01-30

    Transcranial direct current stimulation (tDCS) has generated interest as a treatment modality for schizophrenia. Dopamine, a critical pathogenetic link in schizophrenia, is also known to influence tDCS effects. We evaluated the influence of antipsychotic drug type (as defined by dopamine D2 receptor affinity) on the impact of tDCS in schizophrenia. DSM-IV-TR-diagnosed schizophrenia patients [N=36] with persistent auditory hallucinations despite adequate antipsychotic treatment were administered add-on tDCS. Patients were divided into three groups based on the antipsychotic's affinity to D2 receptors. An auditory hallucinations score (AHS) was measured using the auditory hallucinations subscale of the Psychotic Symptom Rating Scales (PSYRATS). Add-on tDCS resulted in a significant reduction inAHS. Antipsychotic drug type had a significant effect on AHS reduction. Patients treated with high affinity antipsychotics showed significantly lesser improvement compared to patients on low affinity antipsychotics or a mixture of the two. Furthermore, a significant sex-by-group interaction occurred; type of medication had an impact on tDCS effects only in women. Improvement differences could be due to the larger availability of the dopamine receptor system in patients taking antipsychotics with low D2 affinity. Sex-specific differences suggest potential estrogen-mediated effects. This study reports a first-time observation on the clinical utility of antipsychotic drug type in predicting tDCS effects in schizophrenia. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

  5. Transcranial Direct Current Stimulation (tDCS) Enhances the Excitability of Trigemino-Facial Reflex Circuits.

    Cabib, Christopher; Cipullo, Federica; Morales, Merche; Valls-Solé, Josep

    2016-01-01

    Transcranial direct current stimulation (tDCS) causes a tiny burning sensation through activation of local cutaneous trigeminal afferents. Trigeminal sensory inputs from tDCS may generate excitability changes in the trigemino-facial reflex circuits. Sixteen healthy volunteers were submitted to 20 minutes tDCS sessions with two types of electrode-montage conditions: 1. Real vs Sham 'bi-hemispheric' tDCS (cathode/anode: C4/C3), for blinded assessment of effects, and 2. 'uni-hemispheric' tDCS (cathode/anode: Fp3/C3), for assessment of laterality of the effects. Supraorbital nerve stimuli were used to obtain blink reflexes before, during (10 minutes from onset) and after (30 minutes from onset) the tDCS session. Outcome measures were R2 habituation (R2H) to repeated stimuli, the blink reflex excitability recovery (BRER) to paired stimuli and the blink reflex inhibition by a prepulse (BRIP). Real but not sham bi-hemispheric tDCS caused a significant decrease of R2H and leftward shift of BRER curve (p tDCS on BRER and BRIP were larger on ipsilateral than on contralateral blink reflexes (p tDCS enhances the excitability of trigemino-facial reflex circuits. The finding of larger ipsilateral than contralateral effects suggests that sensitization through cutaneous trigeminal afferents adds on other possible mechanisms such as activation of cortico-nuclear or cortico-reticular connections. Copyright © 2016 Elsevier Inc. All rights reserved.

  6. Development of a piping thickness monitoring system using equipotential switching direct current potential drop method

    Kyung Ha, Ryu; Na Young, Lee; Il Soon, Hwang

    2007-01-01

    As nuclear power plants age, low alloy steel piping undergoes wall thickness reduction due to Flow Accelerated Corrosion (FAC). Persisting pipe rupture accidents prompted thinned pipe management programs. As a consequence extensive inspection activities are made based on the Ultrasonic Technique (UT). As the inspection points increase, time is needed to cover required inspection areas. In this paper, we present the Wide Range Monitoring (WiRM) concept with Equipotential Switching Direct Current Potential Drop (ES-DCPD) method by which FAC-active areas can be screened for detailed UT inspections. To apply ES-DCPD, we developed an electric resistance network model and electric field model based on Finite Element Analysis (FEA) to verify its feasibility. Experimentally we measured DCPD of the pipe elbow and confirmed the validity using UT inspections. For a more realistic validation test, we designed a high temperature flow test loop with environmental parameters turned for FAC simulation in the laboratory. Using electrochemical monitoring of water chemistry and local flow velocity prediction by computational fluid dynamic model, FAC rate is estimated. Based on the FAC prediction model and the simulation loop test, we plan to demonstrate the applicability of ES-DCPD in the PWR secondary environment. (authors)

  7. Current status and future directions of development of PR/PP evaluation methodology

    Kim, D. Y.; Kwon, E. H.; Kim, H. D.

    2012-01-01

    A mandatory design requirement for the introduction of generation IV nuclear energy systems (NESs) is defined as the characteristic of a nuclear energy system that impedes the diversion or undeclared production of nuclear material, or misuse of technology, by State in order to acquire nuclear weapons or other nuclear explosive devices. The same report also defines physical protection (PP) as the use of technical, administrative, and operational measures to prevent the theft of nuclear/radioactive material for the purpose of producing nuclear weapons, producing nuclear devices for nuclear terrorism, or using the facility or transportation system for radiological sabotage. Since the early 1970s right after the Indian nuclear test, the international community has recognized the limits of political and diplomatic means to prevent overt proliferation by states and looked for ways to incorporate technical features that are inherent in NESs. As a first step, active research has been conducted to develop a methodology to evaluate PR and PP components of NESs and has now been reduced to two main R and D streams: the Generation IV International Forum (GIF) and International Project on Innovative Nuclear Reactors and Fuel Cycles (INPRO). (Currently, GIF and INPRO are leading the debate as major projects for PR and PP evaluation methods.) This paper presents an overview of the R and D accomplishments during the development of PR and PP evaluation methodology. It also suggests some directions for future research

  8. Current status and future directions of development of PR/PP evaluation methodology

    Kim, D. Y.; Kwon, E. H.; Kim, H. D. [KAERI, Daejeon (Korea, Republic of)

    2012-10-15

    A mandatory design requirement for the introduction of generation IV nuclear energy systems (NESs) is defined as the characteristic of a nuclear energy system that impedes the diversion or undeclared production of nuclear material, or misuse of technology, by State in order to acquire nuclear weapons or other nuclear explosive devices. The same report also defines physical protection (PP) as the use of technical, administrative, and operational measures to prevent the theft of nuclear/radioactive material for the purpose of producing nuclear weapons, producing nuclear devices for nuclear terrorism, or using the facility or transportation system for radiological sabotage. Since the early 1970s right after the Indian nuclear test, the international community has recognized the limits of political and diplomatic means to prevent overt proliferation by states and looked for ways to incorporate technical features that are inherent in NESs. As a first step, active research has been conducted to develop a methodology to evaluate PR and PP components of NESs and has now been reduced to two main R and D streams: the Generation IV International Forum (GIF) and International Project on Innovative Nuclear Reactors and Fuel Cycles (INPRO). (Currently, GIF and INPRO are leading the debate as major projects for PR and PP evaluation methods.) This paper presents an overview of the R and D accomplishments during the development of PR and PP evaluation methodology. It also suggests some directions for future research.

  9. Transcranial direct current stimulation for hyperactivity and noncompliance in autistic disorder.

    D'Urso, Giordano; Bruzzese, Dario; Ferrucci, Roberta; Priori, Alberto; Pascotto, Antonio; Galderisi, Silvana; Altamura, Alfredo Carlo; Bravaccio, Carmela

    2015-01-01

    To evaluate the safety, efficacy, and feasibility of inhibitory transcranial direct current stimulation (tDCS) for the treatment of behavioural abnormalities of autistic patients. Twelve young adult patients with autistic disorder were enrolled. All subjects presented intellectual disability and most of them had speech impairment. The Aberrant Behavior Checklist (ABC) was administered as the primary outcome measure before and after a 2-week tDCS course. All subjects received 10 daily applications of 20 min/1.5 mA/cathodal (inhibitory) tDCS over the left dorso-lateral pre-frontal cortex. Eight out of 10 study completers improved in their abnormal behaviours, reaching an average reduction of 26.7% of the total ABC score. The remaining two patients showed no changes. In the whole group of completers, among the five subscales contributing to the significant reduction of the total score, the most remarkable and statistically significant change was seen in the subscale assessing hyperactivity and non-compliance (-35.9%, P = 0.002). No adverse effects were reported. Inhibitory tDCS improved the ABC rating scores for autistic behaviours. Owing to its ease of use, cost-effectiveness and the limited availability of specific treatment strategies, tDCS might be a valid therapeutic option to be tested in autistic patients.

  10. The application of bonded magnet MQP-0 on an electrical direct current motor

    Ridwan; Mujamilah; Gunawan

    2002-01-01

    Isotropic bonded magnet materials using NdFeB produced by rapid quench method, has advantages that can be easily adapted to the costumer demand. The synthesized bonded magnets are mixed of cpoxy resin or polyester as matrix binder with powder magnet of MQP-O The proportions of polymer and magnetic powder are 4060; 50:50; and 6040 volume % of magnet composites. The characterization of magnetic properties was determined by Vibrating Sample Magnetometer (VSM) at P3IB-BATAN and the density was measured by piknometer. The highest energy product maximum, (BH) m ax of magnet composite synthesized by P3IB-BATAN in this activity is 435 MGOeThe quality of magnet components has been tested empirically by changing the magnetic components of an electric direct current motor found in the local market by magnetic components synthesized by P 3IB-BA TAN. The max imum rotation resulted by using P3IB-BATAN is 40 0 00 rpm The magnetic components synthesized in these research activities are functionally work and comparatively the same with the magnetic components found in the local market as an import commodities

  11. High rate deposition of thin film cadmium sulphide by pulsed direct current magnetron sputtering

    Lisco, F., E-mail: F.Lisco@lboro.ac.uk [Centre for Renewable Energy Systems Technology (CREST), School of Electronic, Electrical and Systems Engineering, Loughborough University, Leicestershire LE11 3TU (United Kingdom); Kaminski, P.M.; Abbas, A.; Bowers, J.W.; Claudio, G. [Centre for Renewable Energy Systems Technology (CREST), School of Electronic, Electrical and Systems Engineering, Loughborough University, Leicestershire LE11 3TU (United Kingdom); Losurdo, M. [Institute of Inorganic Methodologies and of Plasmas, IMIP-CNR, via Orabona 4, 70126 Bari (Italy); Walls, J.M. [Centre for Renewable Energy Systems Technology (CREST), School of Electronic, Electrical and Systems Engineering, Loughborough University, Leicestershire LE11 3TU (United Kingdom)

    2015-01-01

    Cadmium Sulphide (CdS) is an important n-type semiconductor widely used as a window layer in thin film photovoltaics Copper Indium Selenide, Copper Indium Gallium (di)Selenide, Copper Zinc Tin Sulphide and Cadmium Telluride (CdTe). Cadmium Sulphide has been deposited using a number of techniques but these techniques can be slow (chemical bath deposition and Radio Frequency sputtering) or the uniformity and the control of thickness can be relatively difficult (close space sublimation). In this paper we report on the development of a process using pulsed Direct Current magnetron sputtering which allows nanometre control of thin film thickness using time only. The CdS thin films deposited in this process are highly uniform and smooth. They exhibit the preferred hexagonal structure at room temperature deposition and they have excellent optical properties. Importantly, the process is highly stable despite the use of a semi-insulating magnetron target. Moreover, the process is very fast. The deposition rate using 1.5 kW of power to a 6-inch circular magnetron was measured to be greater than 8 nm/s. This makes the process suitable for industrial deployment. - Highlights: • Pulsed DC magnetron sputtering of CdS • High deposition rate deposition • Uniform, pinhole free films.

  12. The Joint Effects of Spatial Cueing and Transcranial Direct Current Stimulation on Visual Acuity

    Taly Bonder

    2018-02-01

    Full Text Available The present study examined the mutual influence of cortical neuroenhancement and allocation of spatial attention on perception. Specifically, it explored the effects of transcranial Direct Current Stimulation (tDCS on visual acuity measured with a Landolt gap task and attentional precues. The exogenous cues were used to draw attention either to the location of the target or away from it, generating significant performance benefits and costs. Anodal tDCS applied to posterior occipital area for 15 min improved performance during stimulation, reflecting heightened visual acuity. Reaction times were lower, and accuracy was higher in the tDCS group, compared to a sham control group. Additionally, in post-stimulation trials tDCS significantly interacted with the effect of precuing. Reaction times were lower in valid cued trials (benefit and higher in invalid trials (cost compared to neutrally cued trials, the effect which was pronounced stronger in tDCS group than in sham control group. The increase of cost and benefit effects in the tDCS group was of a similar magnitude, suggesting that anodal tDCS influenced the overall process of attention orienting. The observed interaction between the stimulation of the visual cortex and precueing indicates a magnification of attention modulation.

  13. THE ASSESSMENT OF ENTREPRENEURIAL PERSONALITY: THE CURRENT SITUATION AND FUTURE DIRECTIONS

    Javier Suárez-Álvarez

    2016-01-01

    Full Text Available Entrepreneurship is fundamental in modern society because it represents an important source of innovation, employment, productivity, and growth. While the first theoretical models arose from economic and sociological approaches, psychology provides models that integrate different aspects such as cognitions, attitudes and personality, which allow a more detailed study. The purpose of this paper is to show the main contributions of psychology to the assessment of the enterprising personality. For this purpose, the main models and instruments developed to date were reviewed. The results confirm that the enterprising personality has a multidimensional structure and eight personality traits can be highlighted: achievement motivation, risk-taking, autonomy, self-efficacy, stress tolerance, innovativeness, internal locus of control, and optimism. From a methodological point of view, Item Response Theory and Computerised Adaptive Tests represent the most advanced and modern methods for assessing enterprising personality. There are currently several measurement instruments available. Future areas of research should be directed at the construction of multidimensional models as well as providing alternatives that facilitate a reduction in social desirability and other biases inherent in self-reports.

  14. High rate deposition of thin film cadmium sulphide by pulsed direct current magnetron sputtering

    Lisco, F.; Kaminski, P.M.; Abbas, A.; Bowers, J.W.; Claudio, G.; Losurdo, M.; Walls, J.M.

    2015-01-01

    Cadmium Sulphide (CdS) is an important n-type semiconductor widely used as a window layer in thin film photovoltaics Copper Indium Selenide, Copper Indium Gallium (di)Selenide, Copper Zinc Tin Sulphide and Cadmium Telluride (CdTe). Cadmium Sulphide has been deposited using a number of techniques but these techniques can be slow (chemical bath deposition and Radio Frequency sputtering) or the uniformity and the control of thickness can be relatively difficult (close space sublimation). In this paper we report on the development of a process using pulsed Direct Current magnetron sputtering which allows nanometre control of thin film thickness using time only. The CdS thin films deposited in this process are highly uniform and smooth. They exhibit the preferred hexagonal structure at room temperature deposition and they have excellent optical properties. Importantly, the process is highly stable despite the use of a semi-insulating magnetron target. Moreover, the process is very fast. The deposition rate using 1.5 kW of power to a 6-inch circular magnetron was measured to be greater than 8 nm/s. This makes the process suitable for industrial deployment. - Highlights: • Pulsed DC magnetron sputtering of CdS • High deposition rate deposition • Uniform, pinhole free films

  15. Direct Measurement of Photon Recoil from a Levitated Nanoparticle

    Jain, Vijay; Gieseler, Jan; Moritz, Clemens; Dellago, Christoph; Quidant, Romain; Novotny, Lukas

    2016-06-01

    The momentum transfer between a photon and an object defines a fundamental limit for the precision with which the object can be measured. If the object oscillates at a frequency Ω0 , this measurement backaction adds quanta ℏΩ0 to the oscillator's energy at a rate Γrecoil, a process called photon recoil heating, and sets bounds to coherence times in cavity optomechanical systems. Here, we use an optically levitated nanoparticle in ultrahigh vacuum to directly measure Γrecoil. By means of a phase-sensitive feedback scheme, we cool the harmonic motion of the nanoparticle from ambient to microkelvin temperatures and measure its reheating rate under the influence of the radiation field. The recoil heating rate is measured for different particle sizes and for different excitation powers, without the need for cavity optics or cryogenic environments. The measurements are in quantitative agreement with theoretical predictions and provide valuable guidance for the realization of quantum ground-state cooling protocols and the measurement of ultrasmall forces.

  16. Strong Measurements Give a Better Direct Measurement of the Quantum Wave Function.

    Vallone, Giuseppe; Dequal, Daniele

    2016-01-29

    Weak measurements have thus far been considered instrumental in the so-called direct measurement of the quantum wave function [4J. S. Lundeen, Nature (London) 474, 188 (2011).]. Here we show that a direct measurement of the wave function can be obtained by using measurements of arbitrary strength. In particular, in the case of strong measurements, i.e., those in which the coupling between the system and the measuring apparatus is maximum, we compared the precision and the accuracy of the two methods, by showing that strong measurements outperform weak measurements in both for arbitrary quantum states in most cases. We also give the exact expression of the difference between the original and reconstructed wave function obtained by the weak measurement approach; this will allow one to define the range of applicability of such a method.

  17. Directly Measuring the Degree of Quantum Coherence using Interference Fringes

    Wang, Yi-Tao; Tang, Jian-Shun; Wei, Zhi-Yuan; Yu, Shang; Ke, Zhi-Jin; Xu, Xiao-Ye; Li, Chuan-Feng; Guo, Guang-Can

    2017-01-01

    Quantum coherence is the most distinguished feature of quantum mechanics. It lies at the heart of the quantum-information technologies as the fundamental resource and is also related to other quantum resources, including entanglement. It plays a critical role in various fields, even in biology. Nevertheless, the rigorous and systematic resource-theoretic framework of coherence has just been developed recently, and several coherence measures are proposed. Experimentally, the usual method to measure coherence is to perform state tomography and use mathematical expressions. Here, we alternatively develop a method to measure coherence directly using its most essential behavior—the interference fringes. The ancilla states are mixed into the target state with various ratios, and the minimal ratio that makes the interference fringes of the "mixed state" vanish is taken as the quantity of coherence. We also use the witness observable to witness coherence, and the optimal witness constitutes another direct method to measure coherence. For comparison, we perform tomography and calculate l1 norm of coherence, which coincides with the results of the other two methods in our situation. Our methods are explicit and robust, providing a nice alternative to the tomographic technique.

  18. TESTING CPT SYMMETRY WITH CURRENT AND FUTURE CMB MEASUREMENTS

    Li, Si-Yu; Zhang, Xinmin [Theory Division, Institute of High Energy Physics, Chinese Academy of Science, P.O. Box 918-4, Beijing 100049 (China); Xia, Jun-Qing; Li, Hong [Key Laboratory of Particle Astrophysics, Institute of High Energy Physics, Chinese Academy of Science, P.O. Box 918-3, Beijing 100049 (China); Li, Mingzhe, E-mail: xiajq@ihep.ac.cn [Interdisciplinary Center for Theoretical Study, University of Science and Technology of China, Hefei, Anhui 230026 (China)

    2015-02-01

    In this paper, we use the current and future cosmic microwave background (CMB) experiments to test the Charge-Parity-Time Reversal (CPT) symmetry. We consider a CPT-violating interaction in the photon sector L{sub cs}∼p{sub μ}A{sub ν} F-tilde {sup μν}, which gives rise to a rotation of the polarization vectors of the propagating CMB photons. By combining the 9 yr WMAP, BOOMERanG 2003, and BICEP1 observations, we obtain the current constraint on the isotropic rotation angle α-bar =−2.12±1.14 (1σ), indicating that the significance of the CPT violation is about 2σ. Here, we particularly take the systematic errors of CMB measurements into account. Then, we study the effects of the anisotropies of the rotation angle [Δα( n-hat )] on the CMB polarization power spectra in detail. Due to the small effects, the current CMB polarization data cannot constrain the related parameters very well. We obtain the 95% C.L. upper limit of the variance of the anisotropies of the rotation angle C {sup α}(0) < 0.035 from all of the CMB data sets. More interestingly, including the anisotropies of rotation angle could lower the best-fit value of r and relax the tension on the constraints of r between BICEP2 and Planck. Finally, we investigate the capabilities of future Planck polarization measurements on α-bar and Δα( n-hat ). Benefited from the high precision of Planck data, the constraints of the rotation angle can be significantly improved.

  19. Effects of Transcranial Direct Current Stimulation (tDCS) on Behaviour and Electrophysiology of Language Production

    Wirth, Miranka; Rahman, Rasha Abdel; Kuenecke, Janina; Koenig, Thomas; Horn, Helge; Sommer, Werner; Dierks, Thomas

    2011-01-01

    Excitatory anodal transcranial direct current stimulation (A-tDCS) over the left dorsal prefrontal cortex (DPFC) has been shown to improve language production. The present study examined neurophysiological underpinnings of this effect. In a single-blinded within-subject design, we traced effects of A-tDCS compared to sham stimulation over the left…

  20. Boosting Cognition : Effects of Multiple-Session Transcranial Direct Current Stimulation on Working Memory

    Talsma, L.J.; Kroese, H.A.; Slagter, H.A.

    Transcranial direct current stimulation (tDCS) is a promising tool for neurocognitive enhancement. Several studies have shown that just a single session of tDCS over the left dorsolateral pFC (lDLPFC) can improve the core cognitive function of working memory (WM) in healthy adults. Yet, recent

  1. Subcortical structures in humans can be facilitated by transcranial direct current stimulation

    Nonnekes, J.H.; Arrogi, A.; Munneke, M.A.M.; Asseldonk, E.H. van; Nijhuis, L.B.; Geurts, A.C.H.; Weerdesteyn, V.G.M.

    2014-01-01

    Transcranial direct current stimulation (tDCS) is a noninvasive brain stimulation technique that alters cortical excitability. Interestingly, in recent animal studies facilitatory effects of tDCS have also been observed on subcortical structures. Here, we sought to provide evidence for the potential

  2. Subcortical Structures in Humans Can Be Facilitated by Transcranial Direct Current Stimulation

    Nonnekes, Johan Hendrik; Arrogi, A.; Munneke, M.A.M.; van Asseldonk, Edwin H.F.; Oude Nijhuis, L.B.; Geurts, A.C.; Weerdesteyn, V.

    2014-01-01

    Transcranial direct current stimulation (tDCS) is a noninvasive brain stimulation technique that alters cortical excitability. Interestingly, in recent animal studies facilitatory effects of tDCS have also been observed on subcortical structures. Here, we sought to provide evidence for the potential

  3. Simulating Transcranial Direct Current Stimulation With a Detailed Anisotropic Human Head Model

    Rampersad, S.; Janssen, A.J.E.M.; Lucka, F.; Aydin, U.; Lanfer, B.; Lew, S.; Wolters, C.H.; Stegeman, D.F.; Oostendorp, T.F.

    2014-01-01

    Transcranial direct current stimulation (tDCS) is a noninvasive brain stimulation technique able to induce long-lasting changes in cortical excitability that can benefit cognitive functioning and clinical treatment. In order to both better understand the mechanisms behind tDCS and possibly improve

  4. Simulating transcranial direct current stimulation with a detailed anisotropic human head model

    Rampersad, S.M.; Janssen, A.M.; Lucka, F.; Aydin, U.; Lanfer, B.; Lew, S.; Wolters, C.H.; Stegeman, D.F.; Oostendorp, T.F.

    2014-01-01

    Transcranial direct current stimulation (tDCS) is a noninvasive brain stimulation technique able to induce long-lasting changes in cortical excitability that can benefit cognitive functioning and clinical treatment. In order to both better understand the mechanisms behind tDCS and possibly improve

  5. Neuroprotective effect of cathodal transcranial direct current stimulation in a rat stroke model.

    Notturno, Francesca; Pace, Marta; Zappasodi, Filippo; Cam, Etrugul; Bassetti, Claudio L; Uncini, Antonino

    2014-07-15

    Experimental focal brain ischemia generates in the penumbra recurrent depolarizations which spread across the injured cortex inducing infarct growth. Transcranial direct current stimulation can induce a lasting, polarity-specific, modulation of cortical excitability. To verify whether cathodal transcranial direct current stimulation could reduce the infarct size and the number of depolarizations, focal ischemia was induced in the rat by the 3 vessels occlusion technique. In the first experiment 12 ischemic rats received cathodal stimulation (alternating 15 min on and 15 min off) starting 45 min after middle cerebral artery occlusion and lasting 4 h. In the second experiment 12 ischemic rats received cathodal transcranial direct current stimulation with the same protocol but starting soon after middle cerebral artery occlusion and lasting 6 h. In both experiments controls were 12 ischemic rats not receiving stimulation. Cathodal stimulation reduced the infarct volume in the first experiment by 20% (p=0.002) and in the second by 30% (p=0.003). The area of cerebral infarction was smaller in animals receiving cathodal stimulation in both experiments (p=0.005). Cathodal stimulation reduced the number of depolarizations (p=0.023) and infarct volume correlated with the number of depolarizations (p=0.048). Our findings indicate that cathodal transcranial direct current stimulation exert a neuroprotective effect in the acute phase of stroke possibly decreasing the number of spreading depolarizations. These findings may have translational relevance and open a new avenue in neuroprotection of stroke in humans. Copyright © 2014. Published by Elsevier B.V.

  6. A clinical trial with combined transcranial direct current stimulation and alcohol approach bias retraining

    den Uyl, T.E.; Gladwin, T.E.; Rinck, M.; Lindenmeyer, J.; Wiers, R.W.

    2017-01-01

    Two studies showed an improvement in clinical outcomes after alcohol approach bias retraining, a form of Cognitive Bias Modification (CBM). We investigated whether transcranial direct current stimulation (tDCS) could enhance effects of CBM. TDCS is a neuromodulation technique that can increase

  7. Cathodal Transcranial Direct Current Stimulation of the Right Wernicke's Area Improves Comprehension in Subacute Stroke Patients

    You, Dae Sang; Kim, Dae-Yul; Chun, Min Ho; Jung, Seung Eun; Park, Sung Jong

    2011-01-01

    Previous studies have shown the appearance of right-sided language-related brain activity in right-handed patients after a stroke. Non-invasive brain stimulation such as transcranial direct current stimulation (tDCS) and repetitive transcranial magnetic stimulation (rTMS) have been shown to modulate excitability in the brain. Moreover, rTMS and…

  8. Improving Naming Abilities among Healthy Young-Old Adults Using Transcranial Direct Current Stimulation

    Lifshitz-Ben-Basat, Adi; Mashal, Nira

    2018-01-01

    Transcranial direct current stimulation (tDCS) is a noninvasive tool to facilitate brain plasticity and enhance language abilities. Our study aims to search for a potential beneficial influence of tDCS on a cognitive linguistic task of naming which found to decline during aging. A group of fifteen healthy old adults (M = 64.93 ± 5.09 years) were…

  9. Single-layer skull approximations perform well in transcranial direct current stimulation modeling

    Rampersad, S.M.; Stegeman, D.F.; Oostendorp, T.F.

    2013-01-01

    In modeling the effect of transcranial direct current stimulation, the representation of the skull is an important factor. In a spherical model, we compared a realistic skull modeling approach, in which the skull consisted of three isotropic layers, to anisotropic and isotropic single-layer

  10. Left Atrial Sphericity Index Predicts Early Recurrence of Atrial Fibrillation After Direct-Current Cardioversion

    Osmanagic, Armin; Möller, Sören; Osmanagic, Azra

    2016-01-01

    BACKGROUND: Attempts to achieve rhythm control using direct-current cardioversion (DCC) are common in those with persistent atrial fibrillation (AF). Although often successful, AF recurs within 1 month in as many as 57% of patients. The aim of this study was to assess whether a baseline left atri...

  11. Trans-spinal direct current stimulation for the modulation of the lumbar spinal motor networks

    Kuck, Alexander

    2018-01-01

    Trans-spinal Direct Current Stimulation (tsDCS) is a noninvasive neuromodulatory tool for the modulation of the spinal neurocircuitry. Initial studies have shown that tsDCS is able to induce a significant and lasting change in spinal-reflex- and corticospinal information processing. It is therefore

  12. Counteracting fatigue in multiple sclerosis with right parietal anodal transcranial direct current stimulation

    Hanken, K.; Bosse, M.; Möhrke, K.; Eling, P.A.T.M.; Kastrup, A.; Antal, A.; Hildebrandt, H.

    2016-01-01

    Background: Fatigue in multiple sclerosis (MS) patients appears to correlate with vigilance decrement as reflected in an increase in reaction time and errors with prolonged time-on-task. Objectives: The aim of this study was to investigate whether anodal transcranial direct current stimulation

  13. Early Childhood Inclusion in the United States: Goals, Current Status, and Future Directions

    Guralnick, Michael J.; Bruder, Mary Beth

    2016-01-01

    The current status and future directions of early childhood inclusion in the United States are discussed from the perspective of 4 key goals: access, accommodations and feasibility, developmental progress, and social integration. Recommendations are put forward to promote inclusion goals emphasizing administrative structures, personnel…

  14. Pharmacologic versus direct-current electrical cardioversion of atrial flutter and fibrillation

    Van Gelder, IC; Tuinenburg, AE; Schoonderwoerd, BS; Tieleman, RG; Crijns, HJGM

    1999-01-01

    Conversion of atrial flutter and atrial fibrillation (AF) can be achieved by either pharmacologic or direct-current (DC) electrical cardioversion. DC electrical cardioversion is more effective and restores sinus rhythm instantaneously; however, general anesthesia is necessary, which can cause severe

  15. Universal "Imaginary Closed Circuit Method" and Formula for Determination of Direction of Induced EMF/Current

    Atram, Dattatraya Balaram

    2011-01-01

    Fleming's right-hand rule and the right-flat-hand rule are generally applied for determining the direction of flow of induced emf/current in straight conductors. The right-hand-fingers rule is applied for coils only. The right-hand-thumb rule can be applied for either straight conductors or coils. Different rules have to be applied for different…

  16. Current in the plasma moving in an arbitrary direction across a magnetic field

    Samokhin, M.V.

    1991-01-01

    Condition under which freezing-in equation is satisfied in case of arbitrarily changeable direction of rate of plasma flow across the magnetic field is considered. It is shown that in the ideally frozen-in plasma there should exist current independent on the flow rate

  17. Rocket-based measurement of Birkeland currents in an active post-midnight aurora

    Coley, W.R.

    1979-01-01

    At 10:45 U.T. on March 1, 1976, an instrumented payload was launched by a Nike-Tomahawk rocket from Poker Flat, Alaska. The payload passed over auroral breakup activity that had a visual intensity of about 150 kR. An electron detector covering the 8 to 10 keV energy range observed electron precipitation while a cesium vapor vector magnetometer measured magnetic perturbations along the vehicle trajectory. From the magnetic measurements a current system consisting of horizontal electrojets and two pairs of oppositely directed field-aligned current sheets was inferred. The total current density carried by these sheets is much larger than that carried by the energetic electrons alone; hence, other particles are the primary current carriers. Data provided by the Chatanika radar facility are used along with other ground-based data to obtain electric fields conductivity estimates, and current densities, which are compared to the currents measured by the flight magnetometer. Results indicate that the ionosphere acts as an electrical load, providing the closing current for Birkeland current flow being generated out in the magnetosphere

  18. 30 CFR 75.703-3 - Approved methods of grounding offtrack mobile, portable and stationary direct-current machines.

    2010-07-01

    ..., portable and stationary direct-current machines. 75.703-3 Section 75.703-3 Mineral Resources MINE SAFETY... stationary direct-current machines. In grounding offtrack direct-current machines and the enclosures of their... requirements: (1) Installation of silicon diodes shall be restricted to electric equipment receiving power from...

  19. Precision Photometric Extinction Corrections from Direct Atmospheric Measurements

    McGraw, John T.; Zimmer, P.; Linford, J.; Simon, T.; Measurement Astrophysics Research Group

    2009-01-01

    For decades astronomical extinction corrections have been accomplished using nightly mean extinction coefficients derived from Langley plots measured with the same telescope used for photometry. Because this technique results in lost time on program fields, observers only grudgingly made sporadic extinction measurements. Occasionally extinction corrections are not measured nightly but are made using tabulated mean monthly or even quarterly extinction coefficients. Any observer of the sky knows that Earth's atmosphere is an ever-changing fluid in which is embedded extinction sources ranging from Rayleigh (molecular) scattering to aerosol, smoke and dust scattering and absorption, to "just plain cloudy.” Our eyes also tell us that the type, direction and degree of extinction changes on time scales of minutes or less - typically shorter than many astronomical observations. Thus, we should expect that atmospheric extinction can change significantly during a single observation. Mean extinction coefficients might be well-defined nightly means, but those means have high variance because they do not accurately record the wavelength-, time-, and angle-dependent extinction actually affecting each observation. Our research group is implementing lidar measurements made in the direction of observation with one minute cadence, from which the absolute monochromatic extinction can be measured. Simultaneous spectrophotometry of nearby bright standard stars allows derivation and MODTRAN modeling atmospheric transmission as a function of wavelength for the atmosphere through which an observation is made. Application of this technique is demonstrated. Accurate real-time extinction measurements are an enabling factor for sub-1% photometry. This research is supported by NSF Grant 0421087 and AFRL Grant #FA9451-04-2-0355.

  20. Revision of the Euratom basic safety standards directive-current status

    Mundig, S.

    2011-01-01

    The European Commission is currently developing a revised Euratom Basic Safety Standards (BSS) Directive covering two major objectives: the consolidation of existing Euratom Radiation Protection legislation and the revision of the Euratom BSS. The consolidation will merge the following five Directives into one single Directive: the BSS Directive, the Medical Exposures Directive, the Public Information Directive, the Outside Workers Directive and the Directive on the Control of high-activity sealed radioactive sources and orphan sources. The revision of the Euratom BSS will take account of the latest recommendations by the International Commission on Radiological Protection and shall improve clarity of the requirements where appropriate. It is planned to introduce more binding requirements on natural radiation sources, on criteria for exemption and clearance, and on the cooperation between Member States for emergency planning and response. The provisions for regulatory control of planned exposure situations foresee a graded approach commensurate to the magnitude and likelihood of exposures from a practice. Finally, the new BSS shall take account of recent scientific developments. One additional goal is to achieve greater harmonisation between the Euratom BSS and the international BSS. While the requirements on the protection of workers, apprentices and students remain nearly unchanged, the revised BSS will clarify the roles and responsibilities of services and experts involved in technical and practical aspects of radiation protection, such as the occupational health services, the dosimetry services, the radiation protection expert and the medical physics expert. The requirements in the BSS on individual monitoring of category A workers remain unchanged, but the existing guidance on individual monitoring was revised and updated-the technical recommendations for monitoring individuals occupationally exposed to external radiation are published by the European

  1. Modeling of the Direct Current Generator Including the Magnetic Saturation and Temperature Effects

    Alfonso J. Mercado-Samur

    2013-11-01

    Full Text Available In this paper the inclusion of temperature effect on the field resistance on the direct current generator model DC1A, which is valid to stability studies is proposed. First, the linear generator model is presented, after the effect of magnetic saturation and the change in the resistance value due to temperature produced by the field current are included. The comparison of experimental results and model simulations to validate the model is used. A direct current generator model which is a better representation of the generator is obtained. Visual comparison between simulations and experimental results shows the success of the proposed model, because it presents the lowest error of the compared models. The accuracy of the proposed model is observed via Modified Normalized Sum of Squared Errors index equal to 3.8979%.

  2. Transvertebral direct current stimulation paired with locomotor training in chronic spinal cord injury: A case study.

    Powell, Elizabeth Salmon; Carrico, Cheryl; Raithatha, Ravi; Salyers, Emily; Ward, Andrea; Sawaki, Lumy

    2016-01-01

    This double-blind, sham-controlled, crossover case study combined transvertebral direct current stimulation (tvDCS) and locomotor training on a robot-assisted gait orthosis (LT-RGO). Determine whether cathodal tvDCS paired with LT-RGO leads to greater changes in function and neuroplasticity than sham tvDCS paired with LT-RGO. University of Kentucky (UK) HealthCare Stroke and Spinal Cord Neurorehabilitation Research at HealthSouth Cardinal Hill Hospital. A single subject with motor incomplete spinal cord injury (SCI) participated in 24 sessions of sham tvDCS paired with LT-RGO before crossover to 24 sessions of cathodal tvDCS paired with LT-RGO. Functional outcomes were measured with 10 Meter Walk Test (10MWT), 6 Minute Walk Test (6MWT), Spinal Cord Independence Measure-III (SCIM-III) mobility component, lower extremity manual muscle test (MMT), and Berg Balance Scale (BBS). Corticospinal changes were assessed using transcranial magnetic stimulation. Improvement in 10MWT speed, SCIM-III mobility component, and BBS occurred with both conditions. 6MWT worsened after sham tvDCS and improved after cathodal tvDCS. MMT scores for both lower extremities improved following sham tvDCS but decreased following cathodal tvDCS. Corticospinal excitability increased following cathodal tvDCS but not sham tvDCS. These results suggest that combining cathodal tvDCS and LT-RGO may improve functional outcomes, increase corticospinal excitability, and possibly decrease spasticity. Randomized controlled trials are needed to confirm these conclusions. This publication was supported by the National Center for Research Resources and the National Center for Advancing Translational Sciences, National Institutes of Health, through Grant UL1TR000117, and the HealthSouth Cardinal Hill Stroke and Spinal Cord Endowment (1215375670).

  3. Thermal conductivity measurement of HTS tapes and stacks for current lead applications

    Schwarz, Michael; Weiss, Klaus-Peter; Heller, Reinhard; Fietz, Walter H.

    2009-01-01

    The use of high-temperature-superconductors (HTS) within current leads offers a high potential to save cooling-power. The principle of HTS current leads is well established, e.g. for particle accelerators (LHC-CERN) but also on the commercial sector, which offer HTS current leads ready for use in small scale magnets and magnets systems. Future fusion machines currently under construction like ITER, W7-X or JT-60SA also will use HTS current leads. At the moment the standard material for HTS current leads is a Bi 2 Sr 2 Ca 2 Cu 3 O x (BSCCO)-AgAu composite tape. The common way to receive high current capacity current leads is to form stacks by sintering or soldering these tapes together. The solder changes the thermal conductivity of the stacks compared to the single tape in the temperature range from 4 K to 60 K. To estimate the heat flux from the warm environment to the cold application the measurement of the thermal conductivity of the soldered stack is mandatory. Therefore the thermal conductivity of stacks with different number of tapes is investigated. To measure the thermal conduction in the current flow direction, the axial heat flow method is used. Combining these results with FEM simulations gives the possibility to estimate the thermal conductivity normal to the flat tape plane. The resulting anisotropic thermal conductivity can be used to model the behaviour of the HTS tape under thermal disturbances more accurately.

  4. Direct measurements of intermolecular forces by chemical force microscopy

    Vezenov, Dmitri Vitalievich

    1999-12-01

    Detailed description of intermolecular forces is key to understanding a wide range of phenomena from molecular recognition to materials failure. The unique features of atomic force microscopy (AFM) to make point contact force measurements with ultra high sensitivity and to generate spatial maps of surface topography and forces have been extended to include measurements between well-defined organic molecular groups. Chemical modification of AFM probes with self-assembled monolayers (SAMs) was used to make them sensitive to specific molecular interactions. This novel chemical force microscopy (CFM) technique was used to probe forces between different molecular groups in a range of environments (vacuum, organic liquids and aqueous solutions); measure surface energetics on a nanometer scale; determine pK values of the surface acid and base groups; measure forces to stretch and unbind a short synthetic DNA duplex and map the spatial distribution of specific functional groups and their ionization state. Studies of adhesion forces demonstrated the important contribution of hydrogen bonding to interactions between simple organic functionalities. The chemical identity of the tip and substrate surfaces as well as the medium had a dramatic effect on adhesion between model monolayers. A direct correlation between surface free energy and adhesion forces was established. The adhesion between epoxy polymer and model mixed SAMs varied with the amount of hydrogen bonding component in the monolayers. A consistent interpretation of CFM measurements in polar solvents was provided by contact mechanics models and intermolecular force components theory. Forces between tips and surfaces functionalized with SAMs terminating in acid or base groups depended on their ionization state. A novel method of force titration was introduced for highly local characterization of the pK's of surface functional groups. The pH-dependent changes in friction forces were exploited to map spatially the

  5. Activity plan: Directional drilling and environmental measurements while drilling

    Myers, D.A.

    1998-01-01

    This activity plan describes the testing of directional drilling combined with environmental measurements while drilling at two Hanford Site locations. A cold test is to be conducted at the 105A Mock Tank Leak Facility in the 200 East Area. A hot test is proposed to be run at the 216-B-8 tile field north of the 241-B Tank Farm in 200 East Area. Criteria to judge the success, partial success or failure of various aspects of the test are included. The TWRS program is assessing the potential for use of directional drilling because of an identified need to interrogate the vadose zone beneath the single-shell tanks. Because every precaution must be taken to assure that investigation activities do not violate the integrity of the tanks, control of the drill bit and ability to follow a predetermined drill path are of utmost importance and are being tested

  6. Activity plan: Directional drilling and environmental measurements while drilling

    Myers, D.A.

    1998-07-16

    This activity plan describes the testing of directional drilling combined with environmental measurements while drilling at two Hanford Site locations. A cold test is to be conducted at the 105A Mock Tank Leak Facility in the 200 East Area. A hot test is proposed to be run at the 216-B-8 tile field north of the 241-B Tank Farm in 200 East Area. Criteria to judge the success, partial success or failure of various aspects of the test are included. The TWRS program is assessing the potential for use of directional drilling because of an identified need to interrogate the vadose zone beneath the single-shell tanks. Because every precaution must be taken to assure that investigation activities do not violate the integrity of the tanks, control of the drill bit and ability to follow a predetermined drill path are of utmost importance and are being tested.

  7. Bi-directional high-side current sense circuit for switch mode power supplies

    Ekhtiari, Marzieh; Bruun, Erik; Andersen, Michael A. E.

    2014-01-01

    In order to control a power supply using piezoelectric transformer, AC current in the transformer ne eds to be measured. Due to the control strategy it is necessary to measure amplitude, phase angle and zero crossing of this c urrent. In some applications there is common ground between pri mary...

  8. Direct measurement of the intrinsic ankle stiffness during standing.

    Vlutters, M; Boonstra, T A; Schouten, A C; van der Kooij, H

    2015-05-01

    Ankle stiffness contributes to standing balance, counteracting the destabilizing effect of gravity. The ankle stiffness together with the compliance between the foot and the support surface make up the ankle-foot stiffness, which is relevant to quiet standing. The contribution of the intrinsic ankle-foot stiffness to balance, and the ankle-foot stiffness amplitude dependency remain a topic of debate in the literature. We therefore developed an experimental protocol to directly measure the bilateral intrinsic ankle-foot stiffness during standing balance, and determine its amplitude dependency. By applying fast (40 ms) ramp-and-hold support surface rotations (0.005-0.08 rad) during standing, reflexive contributions could be excluded, and the amplitude dependency of the intrinsic ankle-foot stiffness was investigated. Results showed that reflexive activity could not have biased the torque used for estimating the intrinsic stiffness. Furthermore, subjects required less recovery action to restore balance after bilateral rotations in opposite directions compared to rotations in the same direction. The intrinsic ankle-foot stiffness appears insufficient to ensure balance, ranging from 0.93±0.09 to 0.44±0.06 (normalized to critical stiffness 'mgh'). This implies that changes in muscle activation are required to maintain balance. The non-linear stiffness decrease with increasing rotation amplitude supports the previous published research. With the proposed method reflexive effects can be ruled out from the measured torque without any model assumptions, allowing direct estimation of intrinsic stiffness during standing. Copyright © 2015 Elsevier Ltd. All rights reserved.

  9. LEAD SLOWING DOWN SPECTROSCOPY FOR DIRECT Pu MASS MEASUREMENTS

    Ressler, Jennifer J.; Smith, Leon E.; Anderson, Kevin K.

    2008-01-01

    The direct measurement of Pu in previously irradiated fuel assemblies is a recognized need in the international safeguards community. A suitable technology could support more timely and independent material control and accounting (MC and A) measurements at nuclear fuel storage areas, the head-end of reprocessing facilities, and at the product-end of recycled fuel fabrication. Lead slowing down spectroscopy (LSDS) may be a viable solution for directly measuring not only the mass of 239Pu in fuel assemblies, but also the masses of other fissile isotopes such as 235U and 241Pu. To assess the potential viability of LSDS, an LSDS spectrometer was modeled in MCNP5 and 'virtual assays' of nominal PWR assemblies ranging from 0 to 60 GWd/MTU burnup were completed. Signal extraction methods, including the incorporation of nonlinear fitting to account for self-shielding effects in strong resonance regions, are described. Quantitative estimates of Pu uncertainty are given for simplistic and more realistic fuel isotopic inventories calculated using ORIGEN. A discussion of additional signal-perturbing effects that will be addressed in future work, and potential signal extraction approaches that could improve Pu mass uncertainties, are also discussed

  10. Inductive current measurements in an oriented grained YBa2Cu3Ox superconductor

    Kupfer, H.; Keller, C.; Salama, K.; Selvamanickam, V.

    1989-01-01

    The critical current of grain aligned YBa 2 Cu 3 O x bulk material was investigated by inductive flux profile and ac susceptibility measurements. The induced current was directed perpendicular to the a-b plane oriented grains where high values of the transport current, have been previously reported. In spite of the unfavorable geometry of the investigated shielding current, no features of granularity were observed. The results yield a uniform bulk critical current density j c of 3x10 4 A/cm 2 at zero field and 77 K. Field and temperature dependences of this j c are discussed and compared with those in a granular Y-Ba-Cu-O material

  11. Directly measured secondhand smoke exposure and COPD health outcomes

    Balmes John

    2006-06-01

    Full Text Available Abstract Background Although personal cigarette smoking is the most important cause and modulator of chronic obstructive pulmonary disease (COPD, secondhand smoke (SHS exposure could influence the course of the disease. Despite the importance of this question, the impact of SHS exposure on COPD health outcomes remains unknown. Methods We used data from two waves of a population-based multiwave U.S. cohort study of adults with COPD. 77 non-smoking respondents with a diagnosis of COPD completed direct SHS monitoring based on urine cotinine and a personal badge that measures nicotine. We evaluated the longitudinal impact of SHS exposure on validated measures of COPD severity, physical health status, quality of life (QOL, and dyspnea measured at one year follow-up. Results The highest level of SHS exposure, as measured by urine cotinine, was cross-sectionally associated with poorer COPD severity (mean score increment 4.7 pts; 95% CI 0.6 to 8.9 and dyspnea (1.0 pts; 95% CI 0.4 to 1.7 after controlling for covariates. In longitudinal analysis, the highest level of baseline cotinine was associated with worse COPD severity (4.7 points; 95% CI -0.1 to 9.4; p = 0.054, disease-specific QOL (2.9 pts; -0.16 to 5.9; p = 0.063, and dyspnea (0.9 pts; 95% CI 0.2 to 1.6 pts; p Conclusion Directly measured SHS exposure appears to adversely influence health outcomes in COPD, independent of personal smoking. Because SHS is a modifiable risk factor, clinicians should assess SHS exposure in their patients and counsel its avoidance. In public health terms, the effects of SHS exposure on this vulnerable subpopulation provide a further rationale for laws prohibiting public smoking.

  12. Probing Anisotropic Surface Properties of Molybdenite by Direct Force Measurements.

    Lu, Zhenzhen; Liu, Qingxia; Xu, Zhenghe; Zeng, Hongbo

    2015-10-27

    Probing anisotropic surface properties of layer-type mineral is fundamentally important in understanding its surface charge and wettability for a variety of applications. In this study, the surface properties of the face and the edge surfaces of natural molybdenite (MoS2) were investigated by direct surface force measurements using atomic force microscope (AFM). The interaction forces between the AFM tip (Si3N4) and face or edge surface of molybdenite were measured in 10 mM NaCl solutions at various pHs. The force profiles were well-fitted with classical DLVO (Derjaguin-Landau-Verwey-Overbeek) theory to determine the surface potentials of the face and the edge surfaces of molybdenite. The surface potentials of both the face and edge surfaces become more negative with increasing pH. At neutral and alkaline conditions, the edge surface exhibits more negative surface potential than the face surface, which is possibly due to molybdate and hydromolybdate ions on the edge surface. The point of zero charge (PZC) of the edge surface was determined around pH 3 while PZC of the face surface was not observed in the range of pH 3-11. The interaction forces between octadecyltrichlorosilane-treated AFM tip (OTS-tip) and face or edge surface of molybdenite were also measured at various pHs to study the wettability of molybdenite surfaces. An attractive force between the OTS-tip and the face surface was detected. The force profiles were well-fitted by considering DLVO forces and additional hydrophobic force. Our results suggest the hydrophobic feature of the face surface of molybdenite. In contrast, no attractive force between the OTS-tip and the edge surface was detected. This is the first study in directly measuring surface charge and wettability of the pristine face and edge surfaces of molybdenite through surface force measurements.

  13. Measurement of electron- and ion beam energies and currents in a plasma focus discharge

    Yamamoto, Toshikazu; Kondoh, Yoshiomi; Shimoda, Katsuji; Hirano, Katsumi

    1982-01-01

    Measurements of energetic particle beams in a plsma focus with a Mather type device are presented. Rogowski coils are used for time-resolved measurement, and solid-state nuclear track detectors for time-integrated measurement of the beams. In the upstream direction with respect to the discharge current, only the electron beam with the maximum current of several kA was detected, which was approximately one percent of the discharge current. The electron energies of the beam were spread from 0.1 to 1 MeV. In the downstream direction, two successive emissions of ions were observed. The first emission had an extremely high energy of the order of some MeV and a low beam current of less than 10 A. The second emission, the main part of the ion beam, with energies of 100 - 800 keV, followed the first one with a time lag of several tens of nanoseconds, and the beam current reached several tens of amperes. (author)

  14. Surface current dynamics under sea breeze conditions observed by simultaneous HF radar, ADCP and drifter measurements

    Sentchev, Alexei; Forget, Philippe; Fraunié, Philippe

    2017-04-01

    Ocean surface boundary layer dynamics off the southern coast of France in the NW Mediterranean is investigated by using velocity observations by high-frequency (HF) radars, surface drifting buoys and a downward-looking drifting acoustic Doppler current profiler (ADCP). The analysis confirms that velocities measured by HF radars correspond to those observed by an ADCP at the effective depth z f = k -1, where k is wavenumber of the radio wave emitted by the radar. The radials provided by the radars were in a very good agreement with in situ measurements, with the relative errors of 1 and 9 % and root mean square (RMS) differences of 0.02 and 0.04 m/s for monostatic and bistatic radar, respectively. The total radar-based velocities appeared to be slightly underestimated in magnitude and somewhat biased in direction. At the end of the survey period, the difference in the surface current direction, based on HF radar and ADCP data, attained 10°. It was demonstrated that the surface boundary layer dynamics cannot be reconstructed successfully without taking into the account velocity variation with depth. A significant misalignment of ˜30° caused by the sea breeze was documented between the HF radar (HFR-derived) surface current and the background current. It was also found that the ocean response to a moderate wind forcing was confined to the 4-m-thick upper layer. The respective Ekman current attained the maximum value of 0.15 m/s, and the current rotation was found to be lagging the wind by approximately 40 min, with the current vector direction being 15-20° to the left of the wind. The range of velocity variability due to wind forcing was found comparable with the magnitude of the background current variability.

  15. GMTI Direction of Arrival Measurements from Multiple Phase Centers.

    Doerry, Armin W. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Bickel, Douglas L. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2015-03-01

    Ground Moving Target Indicator (GMTI) radar attempts to detect and locate targets with unknown motion. Very slow-moving targets are difficult to locate in the presence of surrounding clutter. This necessitates multiple antenna phase centers (or equivalent) to offer independent Direction of Arrival (DOA) measurements. DOA accuracy and precision generally remains dependent on target Signal-to-Noise Ratio (SNR), Clutter-toNoise Ratio (CNR), scene topography, interfering signals, and a number of antenna parameters. This is true even for adaptive techniques like Space-Time-AdaptiveProcessing (STAP) algorithms.

  16. Directed energy deflection laboratory measurements of common space based targets

    Brashears, Travis; Lubin, Philip; Hughes, Gary B.; Meinhold, Peter; Batliner, Payton; Motta, Caio; Madajian, Jonathan; Mercer, Whitaker; Knowles, Patrick

    2016-09-01

    We report on laboratory studies of the effectiveness of directed energy planetary defense as a part of the DE-STAR (Directed Energy System for Targeting of Asteroids and exploRation) program. DE-STAR and DE-STARLITE are directed energy "stand-off" and "stand-on" programs, respectively. These systems consist of a modular array of kilowatt-class lasers powered by photovoltaics, and are capable of heating a spot on the surface of an asteroid to the point of vaporization. Mass ejection, as a plume of evaporated material, creates a reactionary thrust capable of diverting the asteroid's orbit. In a series of papers, we have developed a theoretical basis and described numerical simulations for determining the thrust produced by material evaporating from the surface of an asteroid. In the DESTAR concept, the asteroid itself is used as the deflection "propellant". This study presents results of experiments designed to measure the thrust created by evaporation from a laser directed energy spot. We constructed a vacuum chamber to simulate space conditions, and installed a torsion balance that holds a common space target sample. The sample is illuminated with a fiber array laser with flux levels up to 60 MW/m2 , which allows us to simulate a mission level flux but on a small scale. We use a separate laser as well as a position sensitive centroid detector to readout the angular motion of the torsion balance and can thus determine the thrust. We compare the measured thrust to the models. Our theoretical models indicate a coupling coefficient well in excess of 100 μN/Woptical, though we assume a more conservative value of 80 μN/Woptical and then degrade this with an optical "encircled energy" efficiency of 0.75 to 60 μN/Woptical in our deflection modeling. Our measurements discussed here yield about 45 μN/Wabsorbed as a reasonable lower limit to the thrust per optical watt absorbed. Results vary depending on the material tested and are limited to measurements of 1 axis, so

  17. Measurement of charm in charged current at HERA

    Zimmermann, Tobias

    2008-12-15

    A measurement of charm production in charged current (CC) polarized electron-proton deep inelastic scattering processes with data from the H1 detector at the HERA collider is presented. This process in principle allows access to the strange quark density in the proton. In total 5460 CC candidate events in e{sup +}p and 6253 in e{sup -}p data are selected in the kinematic range Q{sup 2}>223 GeV{sup 2} and 0.03measured CC cross sections are {sigma}{sub CC}=(28.9{+-} 1.4)+P{sub e}.(28.6{+-}4.7) pb for e{sup +}p and {sigma}{sub CC}=(49.2{+-}2.3)-P{sub e}.(42.5 {+-}6.8) pb for e{sup -}p, where P{sub e} is the lepton beam polarization. While the measured cross section for e{sup +}p data is in agreement with the theoretical prediction, the cross section for e{sup -}p data shows a weaker dependence on P{sub e} than predicted. The charm fractions in the selected CC candidate event samples are extracted using the muon charge asymmetry. Muons originating from charmed hadron decays in CC events at HERA always have the same charge as the beam lepton. The extracted charm fractions in the selected CC candidate event samples are F{sub c}=9.5{+-}8.9{+-}3.0 % for e{sup +}p and F{sub c}=4.4{+-}6.9{+-}2.6 % for e{sup -}p. Due to the large statistical errors of the measured charm fractions, the strange quark density in the proton has not been extracted. (orig.)

  18. Influence of Waveform and Current Direction on Short-Interval Intracortical Facilitation

    Delvendahl, Igor; Lindemann, Hannes; Jung, Nikolai H

    2014-01-01

    -posterior (AP) current direction (AP-AP or PA-PA), whereas current direction was reversed between first and second pulse for half-sine paired-pulse stimulation (PA-AP and AP-PA). RESULTS: Monophasic AP-AP stimulation resulted in stronger early SICF at 1.4 ms relative to late SICF at 2.8 and 4.4 ms, whereas...... monophasic PA-PA stimulation produced SICF of comparable size at all three peaks. With half-sine stimulation the third SICF peak was reduced for PA-AP current orientation compared with AP-PA. CONCLUSION: SICF elicited using monophasic as well as half-sine pulses is affected by current direction at clearly......BACKGROUND: Transcranial magnetic stimulation (TMS) of the human primary motor hand area (M1-HAND) can produce multiple descending volleys in fast-conducting corticospinal neurons, especially so-called indirect waves (I-waves) resulting from trans-synaptic excitation. Facilitatory interaction...

  19. Comparison of HF radar measurements with Eulerian and Lagrangian surface currents

    Röhrs, Johannes; Sperrevik, Ann Kristin; Christensen, Kai Håkon; Broström, Göran; Breivik, Øyvind

    2015-05-01

    High-frequency (HF) radar-derived ocean currents are compared with in situ measurements to conclude if the radar observations include effects of surface waves that are of second order in the wave amplitude. Eulerian current measurements from a high-resolution acoustic Doppler current profiler and Lagrangian measurements from surface drifters are used as references. Directional wave spectra are obtained from a combination of pressure sensor data and a wave model. Our analysis shows that the wave-induced Stokes drift is not included in the HF radar-derived currents, that is, HF radars measure the Eulerian current. A disputed nonlinear correction to the phase velocity of surface gravity waves, which may affect HF radar signals, has a magnitude of about half the Stokes drift at the surface. In our case, this contribution by nonlinear dispersion would be smaller than the accuracy of the HF radar currents, hence no conclusion can be made. Finally, the analysis confirms that the HF radar data represent an exponentially weighted vertical average where the decay scale is proportional to the wavelength of the transmitted signal.

  20. Electrochemical deposition and characterization of zinc–nickel alloys deposited by direct and reverse current

    JELENA B. BAJAT

    2005-12-01

    Full Text Available Zn–Ni alloys electrochemically deposited on steel under various deposition conditions were investigated. The alloys were deposited on a rotating disc electrode and on a steel panel from chloride solutions by direct and reverse current. The influence of reverse plating variables (cathodic and anodic current densities and their time duration on the composition, phase structure and corrosion properties were investigated. The chemical content and phase composition affect the anticorrosive properties of Zn–Ni alloys during exposure to a corrosive agent (3 % NaCl solution. It was shown that the Zn–Ni alloy electrodeposited by reverse current with a full period T = 1 s and r = 0.2 exhibits the best corrosion properties of all the investigated alloys deposited by reverse current.