Analysis of the results obtained by optical measurements in plasma focus equipments

International Nuclear Information System (INIS)

Bilbao, L.; Bruzzone, H.

1982-01-01

The results obtained by shadow and Schlieren photographies and interferometry in a 1MJ plasma focus device of Frascati (CNEN-EURATOM, Italy) are compared with a great number of similar measurement results in several devices of the world. A critical analysis of the above results is presented. (L.C.) [pt

Experimental results on one-pion neutral current reaction in all channels induced by antineutrinos at CERN PS

CERN Document Server

Erriquez, O; Bullock, F W; Cavalli, D; Engel, J P; Fogli-Muciaccia, M T; Gamba, D; Guyonnet, J L; Halsteinslid, A; Henderson, R C W; Huss, D; Jones, T W; Marzari-Chiesa, A; Myklebost, K; Natali, S; Nuzzo, S; Paty, M; Pullia, A; Riccati, L; Riester, J L; Rognebakke, A; Rollier, M; Romero, A

1980-01-01

Single pion production, in antineutrino-nucleon interactions via the neutral current, has been studied in the bubble chamber Gargamelle, filled with propane. Complete analysis of the secondaries, including pi /sup 0/'s, has allowed a detailed study of all channels. After background and nuclear corrections, results are obtained which can be interpreted in terms of isospin structure of the neutral weak current and of the Salam-Weinberg angle. Agreement is found with the currently accepted value of sin/sup 2/ theta /sub w/ and the data suggest an important contribution of I=/sup 3///sub 2/ final states. (11 refs).

Obtaining source current density related to irregularly structured electromagnetic target field inside human body using hybrid inverse/FDTD method.

Science.gov (United States)

Han, Jijun; Yang, Deqiang; Sun, Houjun; Xin, Sherman Xuegang

2017-01-01

Inverse method is inherently suitable for calculating the distribution of source current density related with an irregularly structured electromagnetic target field. However, the present form of inverse method cannot calculate complex field-tissue interactions. A novel hybrid inverse/finite-difference time domain (FDTD) method that can calculate the complex field-tissue interactions for the inverse design of source current density related with an irregularly structured electromagnetic target field is proposed. A Huygens' equivalent surface is established as a bridge to combine the inverse and FDTD method. Distribution of the radiofrequency (RF) magnetic field on the Huygens' equivalent surface is obtained using the FDTD method by considering the complex field-tissue interactions within the human body model. The obtained magnetic field distributed on the Huygens' equivalent surface is regarded as the next target. The current density on the designated source surface is derived using the inverse method. The homogeneity of target magnetic field and specific energy absorption rate are calculated to verify the proposed method.

Quantitative estimation of defects from measurement obtained by remote field eddy current inspection

International Nuclear Information System (INIS)

Davoust, M.E.; Fleury, G.

1999-01-01

Remote field eddy current technique is used for dimensioning grooves that may occurs in ferromagnetic pipes. This paper proposes a method to estimate the depth and the length of corrosion grooves from measurement of a pick-up coil signal phase at different positions close to the defect. Grooves dimensioning needs the knowledge of the physical relation between measurements and defect dimensions. So, finite element calculations are performed to obtain a parametric algebraic function of the physical phenomena. By means of this model and a previously defined general approach, an estimate of groove size may be given. In this approach, algebraic function parameters and groove dimensions are linked through a polynomial function. In order to validate this estimation procedure, a statistical study has been performed. The approach is proved to be suitable for real measurements. (authors)

Electron Beam Return-Current Losses in Solar Flares: Initial Comparison of Analytical and Numerical Results

Science.gov (United States)

Holman, Gordon

2010-01-01

Accelerated electrons play an important role in the energetics of solar flares. Understanding the process or processes that accelerate these electrons to high, nonthermal energies also depends on understanding the evolution of these electrons between the acceleration region and the region where they are observed through their hard X-ray or radio emission. Energy losses in the co-spatial electric field that drives the current-neutralizing return current can flatten the electron distribution toward low energies. This in turn flattens the corresponding bremsstrahlung hard X-ray spectrum toward low energies. The lost electron beam energy also enhances heating in the coronal part of the flare loop. Extending earlier work by Knight & Sturrock (1977), Emslie (1980), Diakonov & Somov (1988), and Litvinenko & Somov (1991), I have derived analytical and semi-analytical results for the nonthermal electron distribution function and the self-consistent electric field strength in the presence of a steady-state return-current. I review these results, presented previously at the 2009 SPD Meeting in Boulder, CO, and compare them and computed X-ray spectra with numerical results obtained by Zharkova & Gordovskii (2005, 2006). The phYSical significance of similarities and differences in the results will be emphasized. This work is supported by NASA's Heliophysics Guest Investigator Program and the RHESSI Project.

Self-propelled prospection methodology: first results obtained in the northeast basin (Uruguay)

International Nuclear Information System (INIS)

Goso, H; Spoturno, J; Peciozzi, F.

2008-01-01

This report refers about uranium prospection methodology in Uruguay and its first results obtained in the northeast basin.The preliminary radiometric researching is carried out four works phases: material preparation, radiometric, statistics analysis, anomalies revision

Overview of galactic results obtained by MAGIC

Energy Technology Data Exchange (ETDEWEB)

Zanin, Roberta

2013-06-15

MAGIC is a system of two atmospheric Cherenkov telescopes which explores the very-high-energy sky, from some tens of GeV up to tens of TeV. Located in the Canary island of La Palma, MAGIC has the lowest energy threshold among the instruments of its kind, well suited to study the still poorly explored energy band below 100 GeV. Although the space-borne gamma-ray telescope Fermi/LAT is sensitive up to 300 GeV, gamma-ray rates drop fast with increasing energy, so γ-ray collection areas larger than 10{sup 4}m{sup 2}, as those provided by grounds-based instruments, are crucial above a few GeV. The combination of MAGIC and Fermi/LAT observations have provided the first astrophysical spectra sampled in the inverse Compton peak region, resulting in a complete coverage from MeV up to TeV energies, as well as the discovery of a pulsed emission in the very-high-energy band. This paper focuses on the latest results on Galactic sources obtained by MAGIC which are highlighted by the detection of the pulsed gamma-ray emission from the Crab pulsar up to 400 GeV. In addition, we will present the morphological study on the W51 complex which allowed to pinpoint the location of the majority of the emission around the interaction point between the supernova remnant W51C and the star forming region W51B, but also to find a possible contribution from the associated pulsar wind nebula. Other important scientific achievements involve the Crab Nebula with an unprecedented spectrum covering three decades in energy starting from 50 GeV and a morphological study of the unidentified source HESS J1857+026 which supports the pulsar wind nebula scenario. Finally we will report on the searches of very-high-energy signals from gamma-ray binaries, mainly LS I 303+ and HESS J0632+057.

CIEMAT interlaboratories comparison of the results obtained in the proficiency test run by IAEA

International Nuclear Information System (INIS)

Gasco, C.; Anton, M. P.; Alvarez, A.; Navarro, N.; Meral, J.; Gonzalez, A.; Higueras Lafaja, E.

2000-01-01

This report contains the results obtained by two different laboratories from CIEMAT after participating in the Proficiency Test organised by IAEA (International Atomic Energy Agency) in 1999. This test involves the analysis of fly ashes containing natural radionuclides and different amounts of added transuranics. The extraction techniques, counting methods and results obtained are detailed. This type of test are used for the labs to achieve their accreditation and check the reliability of the procedures routinely employed. (Author) 4 refs

LEP and results obtained by DELPHI after four years of operation

International Nuclear Information System (INIS)

Blocki, J.

1993-10-01

We characterize the most important problems of modern elementary particles physics, for the solution of which the LEP (Large Electron Positron) accelerator was built. We present the characteristics of this accelerator. The structure and properties of the DELPHI detector are described with special emphasis on the contribution of Polish groups. The most important results obtained so far in the LEP accelerator are discussed. (author). 12 refs, 17 figs, 1 tab

Comparison of the results of radiation transport calculation obtained by means of different programs

International Nuclear Information System (INIS)

Gorbatkov, D.V.; Kruchkov, V.P.

1995-01-01

Verification of calculational results of radiation transport, obtained by the known, programs and constant libraries (MCNP+ENDF/B, ANISN+HILO, FLUKA92) by means of their comparison with the precision results calculations through ROZ-6N+Sadko program constant complex and with experimental data, is carried out. Satisfactory agreement is shown with the MCNP+ENDF/B package data for the energy range of E<14 MeV. Analysis of the results derivations, obtained trough the ANISN-HILO package for E<400 MeV and the FLUKA92 programs of E<200 GeV is carried out. 25 refs., 12 figs., 3 tabs

Current system of the solar wind: results of numerical calculation

International Nuclear Information System (INIS)

Pisanko, Yu.V.

1985-01-01

Results of numerical calculations of surface current in the interplanetary current layer and steady volume current in the solar wind for heliocentric distances (1-10)Rsub(s) (Rsub(s) is the Sun radius) are given. The strength of current dependence on spatial coordinates is considered. Stationary nondissipative magnetohydrodynamic corona expansion (SNMCE) in the reference system rotating with the Sun is studied. Calculations show that three-dimensional current system of nonaxial-symmetric and nonsymmetric relatively to helioequator plane of SNMCE is more complicated than the zonal ring current around the Sun, which is the only component of the current system in spatial symmetric case

Most recent developments in combined radium and high voltage therapy of uterine tumours as shown by the results obtained at the municipal hospital Passau

International Nuclear Information System (INIS)

Moos, G.

1987-01-01

It was the aim of the study described here to review data on healing successes achieved in malignant changes of the uterus. The results obtained were analysed on the bais of tumour stage and, in particular, the radiation dose actually administered. It could be shown that the treatment results currently achieved at this clinic are in keeping with relevant patient data collected previously or by other centres. (orig./MG) [de

Obtaining subjects' consent to publish identifying personal information: current practices and identifying potential issues.

Science.gov (United States)

Yoshida, Akiko; Dowa, Yuri; Murakami, Hiromi; Kosugi, Shinji

2013-11-25

In studies publishing identifying personal information, obtaining consent is regarded as necessary, as it is impossible to ensure complete anonymity. However, current journal practices around specific points to consider when obtaining consent, the contents of consent forms and how consent forms are managed have not yet been fully examined. This study was conducted to identify potential issues surrounding consent to publish identifying personal information. Content analysis was carried out on instructions for authors and consent forms developed by academic journals in four fields (as classified by Journal Citation Reports): medicine general and internal, genetics and heredity, pediatrics, and psychiatry. An online questionnaire survey of editors working for journals that require the submission of consent forms was also conducted. Instructions for authors were reviewed for 491 academic journals (132 for medicine general and internal, 147 for genetics and heredity, 100 for pediatrics, and 112 for psychiatry). Approximately 40% (203: 74 for medicine general and internal, 31 for genetics and heredity, 58 for pediatrics, and 40 for psychiatry) stated that subject consent was necessary. The submission of consent forms was required by 30% (154) of the journals studied, and 10% (50) provided their own consent forms for authors to use. Two journals mentioned that the possible effects of publication on subjects should be considered. Many journal consent forms mentioned the difficulties in ensuring complete anonymity of subjects, but few addressed the study objective, the subjects' right to refuse consent and the withdrawal of consent. The main reason for requiring the submission of consent forms was to confirm that consent had been obtained. Approximately 40% of journals required subject consent to be obtained. However, differences were observed depending on the fields. Specific considerations were not always documented. There is a need to address issues around the study

Kinetic instabilities of thin current sheets: Results of two-and-one-half-dimensional Vlasov code simulations

International Nuclear Information System (INIS)

Silin, I.; Buechner, J.

2003-01-01

Nonlinear triggering of the instability of thin current sheets is investigated by two-and-one-half- dimensional Vlasov code simulations. A global drift-resonant instability (DRI) is found, which results from the lower-hybrid-drift waves penetrating from the current sheet edges to the center where they resonantly interact with unmagnetized ions. This resonant nonlinear instability grows faster than a Kelvin-Helmholtz instability obtained in previous studies. The DRI is either asymmetric or symmetric mode or a combination of the two, depending on the relative phase of the lower-hybrid-drift waves at the edges of the current sheet. With increasing particle mass ratio the wavenumber of the fastest-growing mode increases as kL z ∼(m i /m e ) 1/2 /2 and the growth rate of the DRI saturates at a finite level

Compton current detector

International Nuclear Information System (INIS)

Carvalho Campos, J.S. de.

1984-01-01

The project and construction of a Compton current detector, with cylindrical geometry using teflon as dielectric material; for electromagnetic radiation in range energy between 10 KeV and 2 MeV are described. The measurements of Compton current in teflon were obtained using an electrometer. The Compton current was promoted by photon flux proceeding from X ray sources (MG 150 Muller device) and gamma rays of 60 Co. The theory elaborated to explain the experimental results is shown. The calibration curves for accumulated charge and current in detector in function of exposition rates were obtained. (M.C.K.) [pt

Effect of electrolysis parameters on the morphologies of copper powder obtained at high current densities

Directory of Open Access Journals (Sweden)

Orhan Gökhan

2012-01-01

Full Text Available The effects of copper ion concentrations and electrolyte temperature on the morphologies and on the apparent densities of electrolytic copper powders at high current densities under galvanostatic regime were examined. These parameters were evaluated by the current efficiency of hydrogen evolution. In addition, scanning electron microscopy was used for analyzing the morphology of the copper powders. It was found that the morphology was dependent over the copper ion concentration and electrolyte temperature under same current density (CD conditions. At 150 mA cm-2 and the potential of 1000±20 mV (vs. SCE, porous and disperse copper powders were obtained at low concentrations of Cu ions (0.120 M Cu2+ in 0.50 M H2SO4. Under this condition, high rate of hydrogen evolution reaction took place parallel to copper electrodeposition. The morphology was changed from porous, disperse and cauliflower-like to coral-like, shrub-like and stalk-stock like morphology with the increasing of Cu ion concentrations towards 0.120 M, 0.155 M, 0.315 M, 0.475 M and 0.630 M Cu2+ in 0.5 M H2SO4 respectively at the same CD. Similarly, as the temperature was increased, powder morphology and apparent density were observed to be changed. The apparent density values of copper powders were found to be suitable for many of the powder metallurgy applications.

Westinghouse accident tolerant fuel program. Current results and future plans

Energy Technology Data Exchange (ETDEWEB)

Ray, Sumit; Xu, Peng; Lahoda, Edward; Hallstadius, Lars; Boylan, Frank [Westinghouse Electric Company LLC, Hopkins, SC (United States)

2016-07-15

This paper discusses the current status, results from initial tests, as well as the future direction of the Westinghouse's Accident Tolerant Fuel (ATF) program. The current preliminary testing is addressed that is being performed on these samples at the Massachusetts Institute of Technology (MIT) test reactor, initial results from these tests, as well as the technical learning from these test results. In the Westinghouse ATF approach, higher density pellets play a significant role in the development of an integrated fuel system.

Obtaining patient test results from clinical laboratories: a survey of state law for pharmacists.

Science.gov (United States)

Witry, Matthew J; Doucette, William R

2009-01-01

To identify states with laws that restrict to whom clinical laboratories may release copies of laboratory test results and to describe how these laws may affect pharmacists' ability to obtain patient laboratory test results. Researchers examined state statutes and administrative codes for all 50 states and the District of Columbia at the University of Iowa Law Library between June and July 2007. Researchers also consulted with lawyers, state Clinical Laboratory Improvement Amendments officers, and law librarians. Laws relating to the study objective were analyzed. 34 jurisdictions do not restrict the release of laboratory test results, while 17 states have laws that restrict to whom clinical laboratories can send copies of test results. In these states, pharmacists will have to use alternative sources, such as physician offices, to obtain test results. Pharmacists must consider state law before requesting copies of laboratory test results from clinical laboratories. This may be an issue that state pharmacy associations can address to increase pharmacist access to important patient information.

Applying the computer code ''beam scanning' for obtaining the electron beam energy spectrum and monitoring the beam scanning system with a faraday cup and edge current sensors

International Nuclear Information System (INIS)

Bystrov, P.A.

2014-01-01

The results of experiments simulation, obtained in the development of technique for controlling the parameters of the electron beam in a compact radiation sterilization installation are presented. Calculations were performed with a help of a computer code ''BEAM SCANNING'', developed in MRTI. Proposed a method to obtain the spectrum of the electron beam by simulation the experiments in which a Faraday cup waveforms were measured. Preliminary results are presented. Also the results of the experiments and calculations obtained in the development of the amplitude angle sensors are presented. The experiments for the beam irradiation of lead plates proposed as current sensors were modeled. Results are presented in comparison with experimental data. Also are presented the simulation results for the device designed to control scanning system.

Ohm's law for a current sheet

Science.gov (United States)

Lyons, L. R.; Speiser, T. W.

1985-01-01

The paper derives an Ohm's law for single-particle motion in a current sheet, where the magnetic field reverses in direction across the sheet. The result is considerably different from the resistive Ohm's law often used in MHD studies of the geomagnetic tail. Single-particle analysis is extended to obtain a self-consistency relation for a current sheet which agrees with previous results. The results are applicable to the concept of reconnection in that the electric field parallel to the current is obtained for a one-dimensional current sheet with constant normal magnetic field. Dissipated energy goes directly into accelerating particles within the current sheet.

Contradiction between the results of observations of resistance and critical current quantum oscillations in asymmetric superconducting rings

International Nuclear Information System (INIS)

Gurtovoi, V. L.; Dubonos, S. V.; Karpii, S. V.; Nikulov, A. V.; Tulin, V. A.

2007-01-01

Magnetic field dependences of critical current, resistance, and rectified voltage of asymmetric (half circles of different widths) and symmetrical (half circles of equal widths) aluminum rings close to the super-conducting transition were measured. All these dependences are periodic magnetic field functions with periods corresponding to the flux quantum in the ring. The periodic dependences of critical current measured in opposite directions were found to be close to each other for symmetrical rings and shifted with respect to each other by half the flux quantum in asymmetric rings with ratios between half circle widths of from 1.25 to 2. This shift of the dependences by a quarter of the flux quantum as the ring becomes asymmetric makes critical current anisotropic, which explains the effect of alternating current rectification observed for asymmetric rings. Shifts of the extrema of the periodic dependences of critical current by a quarter of the flux quantum directly contradict the results obtained by measuring asymmetric ring resistance oscillations, whose extrema are, as for symmetrical rings, observed at magnetic fluxes equal to an integer and a half of flux quanta

Deep-sequencing protocols influence the results obtained in small-RNA sequencing.

Directory of Open Access Journals (Sweden)

Joern Toedling

Full Text Available Second-generation sequencing is a powerful method for identifying and quantifying small-RNA components of cells. However, little attention has been paid to the effects of the choice of sequencing platform and library preparation protocol on the results obtained. We present a thorough comparison of small-RNA sequencing libraries generated from the same embryonic stem cell lines, using different sequencing platforms, which represent the three major second-generation sequencing technologies, and protocols. We have analysed and compared the expression of microRNAs, as well as populations of small RNAs derived from repetitive elements. Despite the fact that different libraries display a good correlation between sequencing platforms, qualitative and quantitative variations in the results were found, depending on the protocol used. Thus, when comparing libraries from different biological samples, it is strongly recommended to use the same sequencing platform and protocol in order to ensure the biological relevance of the comparisons.

Applying inversion techniques to derive source currents and geoelectric fields for geomagnetically induced current calculations

Directory of Open Access Journals (Sweden)

J. S. de Villiers

2014-10-01

Full Text Available This research focuses on the inversion of geomagnetic variation field measurement to obtain source currents in the ionosphere. During a geomagnetic disturbance, the ionospheric currents create magnetic field variations that induce geoelectric fields, which drive geomagnetically induced currents (GIC in power systems. These GIC may disturb the operation of power systems and cause damage to grounded power transformers. The geoelectric fields at any location of interest can be determined from the source currents in the ionosphere through a solution of the forward problem. Line currents running east–west along given surface position are postulated to exist at a certain height above the Earth's surface. This physical arrangement results in the fields on the ground having the magnetic north and down components, and the electric east component. Ionospheric currents are modelled by inverting Fourier integrals (over the wavenumber of elementary geomagnetic fields using the Levenberg–Marquardt technique. The output parameters of the inversion model are the current strength, height and surface position of the ionospheric current system. A ground conductivity structure with five layers from Quebec, Canada, based on the Layered-Earth model is used to obtain the complex skin depth at a given angular frequency. This paper presents preliminary and inversion results based on these structures and simulated geomagnetic fields. The results show some interesting features in the frequency domain. Model parameters obtained through inversion are within 2% of simulated values. This technique has applications for modelling the currents of electrojets at the equator and auroral regions, as well as currents in the magnetosphere.

Impact of recirculation on the East Greenland Current in Fram Strait: Results from moored current meter measurements between 1997 and 2009

NARCIS (Netherlands)

de Steur, L.; Hansen, E.; Mauritzen, C.; Beszczynska-Möller, A.; Fahrbach, E.

2014-01-01

Transports of total volume and water masses obtained from a mooring array in the East Greenland Current (EGC) in Fram Strait are presented for the period 1997–2009. The array in the EGC was moved along isobaths from 79°N to 78°50'N78°50'N in 2002 to line up with moorings in the eastern Fram Strait.

Summary of personal neutron dosemeter results obtained within the EVIDOS project

International Nuclear Information System (INIS)

Luszik-Bhadra, M.; Reginatto, M.; Schuhmacher, H.; Bolognese-Milsztajn, T.; Lacoste, V.; Boschung, M.; Fiechtner, A.; Coeck, M.; Vanhavere, F.; Curzio, G.; Errico d', F.; Kylloenen, J.-E.; Lindborg, L.; Bartlett, D.; Tanner, R.

2005-01-01

Full text: Within the EC project EVIDOS ('Evaluation of Individual Dosimetry in Mixed Neutron and Photon Radiation Fields'), different types of neutron personal dosemeters were irradiated in workplace fields in nuclear installations in Europe. Mostly electronic personal neutron dosemeters were tested, among them commercial devices (Thermo Electron EPD-N, Aloka PDM-313), devices from first industrial prototype series (Thermo Electron EPD-N2, Saphydose-n) and laboratory prototypes which were already in the stage of lightweight battery-operated instruments (PTB DOS-2002). In addition, dosemeters with (almost) immediate readout (BTI bubble detectors, Rados DIS-N) and passive dosemeters which needed no fielddependent calibration factors (PADC track detectors from PSI and NRPB) were used, as well as those TLD albedo dosemeters which are routinely used in the facilities visited. The results of measurements obtained within the EVIDOS project in workplace fields in nuclear installations in Europe, i.e. at Kruemmel (boiling water reactor, transport cask), at Mol (Venus research reactor, fuel facility Belgonucleaire) and at Ringhals (pressurized water reactor, transport cask) are presented and compared to reference values of personal dose equivalent H p (10) determined by means of Bonner spheres and novel directional spectrometers. In fields with strong back-scatter and moderation of neutrons, several dosemeters showed overreadings by more than a factor of two. In strongly directed fields with neutron dose equivalent peaked at about 1 MeV (MOX fuel), the same dosemeters showed under-readings of about a factor of two. These under- and over-readings in the workplace fields can be explained in terms of the dosemeter response functions for mono-energetic neutrons, which show over-responses in the thermal and intermediate neutron energy region and under-responses at about 1 MeV neutron energy. The dosemeter readings obtained in the workplace fields were checked for consistency by

New dynamics information from experimental results obtained in d-Au collisions at RHIC-BNL energies

International Nuclear Information System (INIS)

Jipa, Alexandru

2004-01-01

During the last runs d-Au collisions at √s NN = 200 GeV have been investigated at RHIC-BNL using the BRAHMS Experiment. Some interesting experimental results on charged particle multiplicities, rapidity distributions, transverse momentum spectra, antiparticle to particle ratios, participant spectator evolution have been obtained. In this work the most interesting results are presented for different rapidity and collision centrality ranges. Taking into account the importance of the collision geometry and collision symmetry in the collision dynamics, comparisons with the similar experimental results obtained in Au-Au collisions have been done. New interesting results can be reported. The most significant are related to the evolution of the nuclear modification factor with rapidity and collision centrality. The high transverse momentum suppression and the behaviours in different rapidity and centrality ranges suggest strong initial state effects. These effects could be related to the gluonic structure of the colliding nuclei. Some insights on the Color Glass Condensate formation are possible. (author)

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

Energy Technology Data Exchange (ETDEWEB)

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.

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

International Nuclear Information System (INIS)

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

Design, operational experiences and beam results obtained with the SNS H- ion source and LEBT at Berkeley Lab

International Nuclear Information System (INIS)

Keller, R.; Thomae, R.; Stockli, M.; Welton, R.

2002-01-01

The ion source and Low-Energy Transport (LEBT) system that will provide H - ion beams to the Spallation Neutron Source (SNS)** Front End and the accelerator chain have been developed into a mature unit that fully satisfies the operational requirements through the commissioning and early operating phases of SNS. Compared to the early R and D version, many features of the ion source have been improved, and reliable operation at 6% duty factor has been achieved producing beam currents in the 35-mA range and above. LEBT operation proved that the purely electrostatic focusing principle is well suited to inject the ion beam into the RFQ accelerator, including the steering and pre-chopping functions. This paper will discuss the latest design features of the ion source and LEBT, give performance data for the integrated system, and report on commissioning results obtained with the SNS RFQ and Medium-Energy Beam Transport (MEBT) system. Prospects for further improvements will be outlined in concluding remarks

Test results of the 18 kA EDIPO HTS current leads

International Nuclear Information System (INIS)

Wesche, Rainer; Bagnasco, Maurizio; Bruzzone, Pierluigi; Felder, Roland; Guetg, Marc; Holenstein, Manuel; Jenni, Markus; March, Stephen; Roth, Felix; Vogel, Martin

2011-01-01

For the new test facility EDIPO (European DIPOle), to be hosted by CRPP, two 18 kA HTS current leads were manufactured and successfully tested. The HTS module, made of AgMgAu/Bi-2223 tapes, is cooled only by heat conduction to the cold end, while the copper part is cooled by forced flow helium gas. The current leads were tested at low voltage up to the maximum current of 18 kA. The helium mass flow rates required for stable operation at various currents were determined. In addition to the steady state operation, the transient behavior in the case of a loss of flow was studied experimentally. The test results provide an estimate of the operational limits of the EDIPO HTS current leads.

Test results of the 18 kA EDIPO HTS current leads

Energy Technology Data Exchange (ETDEWEB)

Wesche, Rainer, E-mail: rainer.wesche@psi.ch [Ecole Polytechnique Federale de Lausanne (EPFL), Centre de Recherches en Physique des Plasmas (CRPP), Association Euratom - Confederation Suisse, 5232 Villigen PSI (Switzerland); Bagnasco, Maurizio; Bruzzone, Pierluigi; Felder, Roland; Guetg, Marc; Holenstein, Manuel; Jenni, Markus; March, Stephen; Roth, Felix; Vogel, Martin [Ecole Polytechnique Federale de Lausanne (EPFL), Centre de Recherches en Physique des Plasmas (CRPP), Association Euratom - Confederation Suisse, 5232 Villigen PSI (Switzerland)

2011-10-15

For the new test facility EDIPO (European DIPOle), to be hosted by CRPP, two 18 kA HTS current leads were manufactured and successfully tested. The HTS module, made of AgMgAu/Bi-2223 tapes, is cooled only by heat conduction to the cold end, while the copper part is cooled by forced flow helium gas. The current leads were tested at low voltage up to the maximum current of 18 kA. The helium mass flow rates required for stable operation at various currents were determined. In addition to the steady state operation, the transient behavior in the case of a loss of flow was studied experimentally. The test results provide an estimate of the operational limits of the EDIPO HTS current leads.

AC over-current test results of YBCO conductor for YBCO power transformer with fault current limiting function

International Nuclear Information System (INIS)

Tomioka, A.; Otonari, T.; Ogata, T.; Iwakuma, M.; Okamoto, H.; Hayashi, H.; Iijima, Y.; Saito, T.; Gosho, Y.; Tanabe, K.; Izumi, T.; Shiohara, Y.

2011-01-01

The single-layer coils with a diameter of 250 mm and 12 turns were manufactured with YBCO tapes with a CuNi- or Cu-Tape. The AC over-current tests were carried out in subcooled liquid nitrogen at 66 K and 74 K to develop power transformers with current limiting function. The AC over-current was two to seven times larger than the I c of conductor and it was reduced to the same level of I c . The I c of model coils did not degrade. The test results showed the possibility of YBCO superconducting transformers with current limiting function. We are developing elemental technology for 66 kV/6.9 kV 20 MVA-class YBCO power transformer. The YBCO transformer is considered to have a possibility to stabilize the power system by improving function of fault current limiting. Current limiting behavior functions over critical current flows. There is a possibility that superconducting characteristic may be damaged due to increase in temperature of YBCO tapes. Therefore, we have taken a measure to combine YBCO tape with CuNi tape or Cu Tape. We manufactured model coils using these conductors and conducted the AC over-current tests. The test current was two to seven times larger than the I c of conductor and it was damped with time from its maximum value according to the generation of conductor resistance. We verified the effectiveness of current limiting characteristics. In these tests, the I c of model coil did not degrade. We consider this conductor to be able to withstand AC over-current with the function of current limiting.

The effect of deformation after backarc spreading between the rear arc and current volcanic front in Shikoku Basin obtained by seismic reflection survey

Science.gov (United States)

Yamashita, M.; Takahashi, N.; Nakanishi, A.; Kodaira, S.; Tamura, Y.

2012-12-01

Detailed crustal structure information of a back-arc basin must be obtained to elucidate the mechanism of its opening. Especially, the Shikoku Basin, which occupies the northern part of the Philippine Sea Plate between the Kyushu-Palau Ridge and the Izu-Bonin (Ogasawara) Arc, is an important area to understand the evolution of the back-arc basins as a part of the growth process of the Philippine Sea. Especially, the crustal structure oft the east side of Shikoku Basin is complicated by colliding to the Izu Peninsula Japan Agency for Marine-Earth Science and Technology has been carried out many multi-channel seismic reflection surveys since 2004 in Izu-Bonin region. Kodaira et al. (2008) reported the results of a refraction seismic survey along a north-south profile within paleoarc in the rear arc (i.e., the Nishi-shichito ridge) about 150 km west of current volcanic front. According to their results, the variation relationship of crustal thickness between the rear arc and volcanic front is suggested the evidence of rifting from current volcanic arc. There is the en-echelon arrangement is located in the eastern side of Shikoku Basin from current arc to rear arc, and it is known to activate after ceased spreading at 15 Ma (Okino et al., 1994) of Shikoku Basin by geologic sampling of Ishizuka et al. (2003). Our MCS results are also recognized the recent lateral fault zone is located in east side of Shikoku Basin. We carried out high density grid multi-channel seismic reflection (MCS) survey using tuned airgun in order to obtain the relationship between the lateral faults and en-echelon arrangement in KR08-04 cruise. We identified the deformation of sediments in Shikoku Basin after activity of Kanbun seamount at 8 Ma in MCS profile. It is estimated to activate a part of the eastern side of Shikoku Basin after construction of en-echelon arrangement and termination of Shikoku Basin spreading. Based on analyses of magnetic and gravity anomalies, Yamazaki and Yuasa (1998

Lambing results obtained with imported Ile de France rarn semen

African Journals Online (AJOL)

insemination was carried out either 54,5 h (fixed time single ... Table 1 Conception rate obtained using two batches of frozen lle de France ... Pregnant mare serum gonadotrophin (Fostim, 300 ... Effect of initial freezing temperature, addition.

Near-Infrared Scintillation of Liquid Argon: Recent Results Obtained with the NIR Facility at Fermilab

Energy Technology Data Exchange (ETDEWEB)

Escobar, C. O. [Fermilab; Rubinov, P. [Fermilab; Tilly, E. [Sewanee U.

2018-03-19

After a short review of previous attempts to observe and measure the near-infrared scintillation in liquid argon, we present new results obtained with NIR, a dedicated cryostat at the Fermilab Proton Assembly Building (PAB). The new results give confidence that the near-infrared light can be used as the much needed light signal in large liquid argon time projection chambers.11 pages,

Study of neoclassical transport and bootstrap current for W7-X in the 1/upsilon regime, using results from the PIES code

International Nuclear Information System (INIS)

Nemov, V V; Kalyuzhnyj, V N; Kasilov, S V; Drevlak, M; Nuehrenberg, J; Kernbichler, W; Reiman, A; Monticello, D

2004-01-01

For the magnetic field of the Wendelstein 7-X (W7-X) standard high-mirror configuration, computed by the PIES code, taking into account real coil geometry, neoclassical transport and bootstrap current are analysed in the 1/upsilon regime using methods based on the integration along magnetic field lines in a given magnetic field. The zero beta and (beta) = 1% cases are studied. The results are compared to the corresponding results for the vacuum magnetic field directly produced by modular coils. A significant advantage of W7-X over a conventional stellarator resulting from reduced neoclassical transport and from reduced bootstrap current follows from the computations although the neoclassical transport is somewhat larger than that previously obtained for the ideal W7-X model configuration

Near-earth Thin Current Sheets and Birkeland Currents during Substorm Growth Phase

International Nuclear Information System (INIS)

Sorin Zaharia; Cheng, C.Z.

2003-01-01

Two important phenomena observed during the magnetospheric substorm growth phase are modeled: the formation of a near-Earth (|X| ∼ 9 R E ) thin cross-tail current sheet, as well as the equatorward shift of the ionospheric Birkeland currents. Our study is performed by solving the 3-D force-balance equation with realistic boundary conditions and pressure distributions. The results show a cross-tail current sheet with large current (J φ ∼ 10 nA/m 2 ) and very high plasma β (β ∼ 40) between 7 and 10 R E . The obtained region-1 and region-2 Birkeland currents, formed on closed field lines due to pressure gradients, move equatorward and become more intense (J parallel max ∼ 3 (micro)A/m 2 ) compared to quiet times. Both results are in agreement with substorm growth phase observations. Our results also predict that the cross-tail current sheet maps into the ionosphere in the transition region between the region-1 and region-2 currents

Experimental results of current distribution in Rutherford-type LHC cables

CERN Document Server

Verweij, A P

2000-01-01

Current distribution among the wires of multi-strand superconducting cables is an important item for accelerator magnets. A non-uniform distribution could cause additional field distortions in the magnet bore and can as well be one of the reasons of premature quenching. Since two years electrical measurements on superconducting Rutherford-type cables are performed at CERN as part of the reception tests for the Large Hadron Collider (LHC). Cable samples of 2.4 m length are tested at currents up to 32 kA, temperatures around 1.9 and 4.3 K, and fields up to 10 T, applied perpendicularly as well as parallel to the broad face of the cable. Last year, an array of 24 Hall probes was installed in the test set-up in order to measure the self-field of the cable samples along one cable pitch. Each of the probes measures the local field generated by the current in the strands close by, and the results of the all probes reflect therefore the distribution of the strand currents. Experiments are done varying the applied fie...

Results of Investigative Tests of Gas Turbine Engine Compressor Blades Obtained by Electrochemical Machining

Science.gov (United States)

Kozhina, T. D.; Kurochkin, A. V.

2016-04-01

The paper highlights results of the investigative tests of GTE compressor Ti-alloy blades obtained by the method of electrochemical machining with oscillating tool-electrodes, carried out in order to define the optimal parameters of the ECM process providing attainment of specified blade quality parameters given in the design documentation, while providing maximal performance. The new technological methods suggested based on the results of the tests; in particular application of vibrating tool-electrodes and employment of locating elements made of high-strength materials, significantly extend the capabilities of this method.

Results obtained on dileptons and prospects

International Nuclear Information System (INIS)

Roche, G.

1992-01-01

Experimental results (mostly from the DLS collaboration at LBL) and model calculations of dielectron production in pp/pd/pBe (1-5 GeV) and CaCa (1-2 GeV/A) are presented. Dileptons appear to be a suitable probe to approach in-medium properties of hadrons in nuclear matter. At the present time, the ρ/ω region looks the most promising. Oncoming programs are briefly presented, in particular the HADES project at GSI. 7 figs

Isotopic identification using Pulse Shape Analysis of current signals from silicon detectors: Recent results from the FAZIA collaboration

Energy Technology Data Exchange (ETDEWEB)

Pastore, G., E-mail: pastore@fi.infn.it [Dipartimento di Fisica, Università di Firenze, via G.Sansone 1, 50019 Sesto Fiorentino (Italy); INFN Sezione di Firenze, via G.Sansone 1, 50019 Sesto Fiorentino (Italy); Gruyer, D. [INFN Sezione di Firenze, via G.Sansone 1, 50019 Sesto Fiorentino (Italy); Ottanelli, P. [Dipartimento di Fisica, Università di Firenze, via G.Sansone 1, 50019 Sesto Fiorentino (Italy); INFN Sezione di Firenze, via G.Sansone 1, 50019 Sesto Fiorentino (Italy); Le Neindre, N. [LPC Caen, Normandie Univ, ENSICAEN, UNICAEN, CNRS/IN2P3, LPC Caen, 14000 Caen (France); Pasquali, G. [Dipartimento di Fisica, Università di Firenze, via G.Sansone 1, 50019 Sesto Fiorentino (Italy); INFN Sezione di Firenze, via G.Sansone 1, 50019 Sesto Fiorentino (Italy); Alba, R. [INFN LNS, Via S.Sofia 62, 95123 Catania (Italy); Barlini, S.; Bini, M. [Dipartimento di Fisica, Università di Firenze, via G.Sansone 1, 50019 Sesto Fiorentino (Italy); INFN Sezione di Firenze, via G.Sansone 1, 50019 Sesto Fiorentino (Italy); Bonnet, E. [SUBATECH, EMN-IN2P3/CNRS-Université de Nantes, Nantes (France); GANIL, CEA/DSM-CNRS/IN2P3, B.P. 5027, F-14076 Caen Cedex (France); Borderie, B. [Institut de Physique Nucléaire, CNRS-IN2P3, Univ. Paris-Sud, Université Paris-Saclay, F-91406 Orsay Cedex (France); Bougault, R. [LPC Caen, Normandie Univ, ENSICAEN, UNICAEN, CNRS/IN2P3, LPC Caen, 14000 Caen (France); Bruno, M. [INFN, Sezione di Bologna, Viale Berti Pichat 6/2, 40127 Bologna (Italy); Casini, G. [INFN Sezione di Firenze, via G.Sansone 1, 50019 Sesto Fiorentino (Italy); Chbihi, A. [GANIL, CEA/DSM-CNRS/IN2P3, B.P. 5027, F-14076 Caen Cedex (France); and others

2017-07-11

The FAZIA apparatus exploits Pulse Shape Analysis (PSA) to identify nuclear fragments stopped in the first layer of a Silicon-Silicon-CsI(Tl) detector telescope. In this work, for the first time, we show that the isotopes of fragments having atomic number as high as Z∼20 can be identified. Such a remarkable result has been obtained thanks to a careful construction of the Si detectors and to the use of low noise and high performance digitizing electronics. Moreover, optimized PSA algorithms are needed. This work deals with the choice of the best algorithm for PSA of current signals. A smoothing spline algorithm is demonstrated to give optimal results without requiring too much computational resources.

First results obtained from the Cello liquid argon end cap calorimeters

International Nuclear Information System (INIS)

Le Diberder, F.

1981-05-01

The Cello liquid argon calorimeter is presented in the first part of this thesis. The cryogenic system has to supply three cryostats filled with liquid argon: one cylindrical cryostat of 25 m 3 volume contains 2x8 separate modules; each of the two symmetric end cap cryostats contains two half cylindrical modules. Each module in the end cap part consists of 42 layers of lead strips interleaved with 43 full plates. The strips are alternatively vertical, horizontal and circular. In front of the lead calorimeter are 4 planes of copper foils glued on epoxy for dE/dx measurement. The electronics, signal processing and data acquisition system are described. In the second part, the performance and analysis of data measured by the end cap calorimeters are reported: study of Bhabha scattering e + e - → e + e - ; preliminary results obtained in two photon physics e + e - → e + e - γγ → e + e - X [fr

Eddy current inspection of tubing

International Nuclear Information System (INIS)

Bauza, J. L. R.; Herrero, J.; Diaz, J.

1966-01-01

The Experimental research work carried out to develop a Eddy current testing equipment is described. Search coils with ferrite or air cores were used and the obtained results are discussed. Valuable information was gained from a improved channel in which a direct measure of the defect and the reference signal phase difference is obtained. Artificial defect used to evaluate resolution and sensitivity were produced by electro-machining and mechanical means. Finned SAP tubing was tested in a routine basis with the described equipment and the results plotted. Basic and theoretical considerations on the Eddy current testing technique are given in the last section of this report. (Author)

Prediction of SFL Interruption Performance from the Results of Arc Simulation during High-Current Phase

Science.gov (United States)

Lee, Jong-Chul; Lee, Won-Ho; Kim, Woun-Jea

2015-09-01

The design and development procedures of SF6 gas circuit breakers are still largely based on trial and error through testing although the development costs go higher every year. The computation cannot cover the testing satisfactorily because all the real processes arc not taken into account. But the knowledge of the arc behavior and the prediction of the thermal-flow inside the interrupters by numerical simulations are more useful than those by experiments due to the difficulties to obtain physical quantities experimentally and the reduction of computational costs in recent years. In this paper, in order to get further information into the interruption process of a SF6 self-blast interrupter, which is based on a combination of thermal expansion and the arc rotation principle, gas flow simulations with a CFD-arc modeling are performed during the whole switching process such as high-current period, pre-current zero period, and current-zero period. Through the complete work, the pressure-rise and the ramp of the pressure inside the chamber before current zero as well as the post-arc current after current zero should be a good criterion to predict the short-line fault interruption performance of interrupters.

High current density ion beam obtained by a transition to a highly focused state in extremely low-energy region

Energy Technology Data Exchange (ETDEWEB)

Hirano, Y., E-mail: y.hirano@aist.go.jp, E-mail: hirano.yoichi@phys.cst.nihon-u.ac.jp [Innovative Plasma Processing Group, National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, Ibaraki 305-8568 (Japan); College of Science and Technologies, Nihon University, Chiyodaku, Tokyo 101-0897 (Japan); Kiyama, S.; Koguchi, H. [Innovative Plasma Processing Group, National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, Ibaraki 305-8568 (Japan); Fujiwara, Y.; Sakakita, H. [Innovative Plasma Processing Group, National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, Ibaraki 305-8568 (Japan); Department of Engineering Mechanics and Energy, University of Tsukuba, Ibaraki 305-8577 (Japan)

2015-11-15

A high current density (≈3 mA/cm{sup 2}) hydrogen ion beam source operating in an extremely low-energy region (E{sub ib} ≈ 150–200 eV) has been realized by using a transition to a highly focused state, where the beam is extracted from the ion source chamber through three concave electrodes with nominal focal lengths of ≈350 mm. The transition occurs when the beam energy exceeds a threshold value between 145 and 170 eV. Low-level hysteresis is observed in the transition when E{sub ib} is being reduced. The radial profiles of the ion beam current density and the low temperature ion current density can be obtained separately using a Faraday cup with a grid in front. The measured profiles confirm that more than a half of the extracted beam ions reaches the target plate with a good focusing profile with a full width at half maximum of ≈3 cm. Estimation of the particle balances in beam ions, the slow ions, and the electrons indicates the possibility that the secondary electron emission from the target plate and electron impact ionization of hydrogen may play roles as particle sources in this extremely low-energy beam after the compensation of beam ion space charge.

Presal36: a high resolution ocean current model for Brazilian pre-salt area: implementation and validation results

Energy Technology Data Exchange (ETDEWEB)

Schoellkopf, Jacques P. [Advanced Subsea do Brasil Ltda., Rio de Janeiro, RJ (Brazil)

2012-07-01

The PRESAL 36 JIP is a project for the development of a powerful Ocean Current Model of 1/36 of a degree resolution, nested in an existing Global Ocean global Model, Mercator PSY4 (1/12-a-degree resolution ), with tide corrections, improved bathymetry accuracy and high frequency atmospheric forcing (every 3 hours). The simulation outputs will be the 3 dimensional structure of the velocity fields (u,v,w) at 50 vertical levels over the water column, including geostrophic, Ekman and tidal currents, together with Temperature, Salinity and sea surface height at a sub-mesoscale spatial resolution. Simulations will run in hindcast, nowcast and forecast modes, with a temporal resolution of 3 hours . This Ocean current model will allow to perform detailed statistical studies on various areas using conditions analysed using hindcast mode, short term operational condition prediction for various surface and sub sea operations using realtime and Forecast modes. The paper presents a publication of significant results of the project, in term of pre-sal zoomed model implementation, and high resolution model validation. It demonstrate the capability to properly describe ocean current phenomenon at beyond mesoscale frontier. This project demonstrate the feasibility of obtaining accurate information for engineering studies and operational conditions, based on a 'zoom technique' starting from global ocean models. (author)

Recent results with a high-current, heavy-ion source system

International Nuclear Information System (INIS)

Keller, R.; Spaedtke, P.; Emig, H.

1986-01-01

In the last conference of this series, an improved high-current ion source for gases, CORDIS was presented. This source has been further developed to allow the processing of substances which are not volatile at room temperature. One of these modifications, HORDIS, incorporates an oven whereas the third version works at rather moderate temperatures and can be fed through a slightly heated external bottle. With this source system, high-current ion beams in the 100 mA range can be produced for a considerable part of the periodic table. Operation parameters and experiences with the sources are discussed, and the most recent results for all versions are given. (author)

Ocean current surface measurement using dynamic elevations obtained by the GEOS-3 radar altimeter

Science.gov (United States)

Leitao, C. D.; Huang, N. E.; Parra, C. G.

1977-01-01

Remote Sensing of the ocean surface from the GEOS-3 satellite using radar altimeter data has confirmed that the altimeter can detect the dynamic ocean topographic elevations relative to an equipotential surface, thus resulting in a reliable direct measurement of the ocean surface. Maps of the ocean dynamic topography calculated over a one month period and with 20 cm contour interval are prepared for the last half of 1975. The Gulf Stream is observed by the rapid slope change shown by the crowding of contours. Cold eddies associated with the current are seen as roughly circular depressions.

Determination of High-Frequency Current Distribution Using EMTP-Based Transmission Line Models with Resulting Radiated Electromagnetic Fields

Energy Technology Data Exchange (ETDEWEB)

Mork, B; Nelson, R; Kirkendall, B; Stenvig, N

2009-11-30

Application of BPL technologies to existing overhead high-voltage power lines would benefit greatly from improved simulation tools capable of predicting performance - such as the electromagnetic fields radiated from such lines. Existing EMTP-based frequency-dependent line models are attractive since their parameters are derived from physical design dimensions which are easily obtained. However, to calculate the radiated electromagnetic fields, detailed current distributions need to be determined. This paper presents a method of using EMTP line models to determine the current distribution on the lines, as well as a technique for using these current distributions to determine the radiated electromagnetic fields.

On the dynamics of the Mouth of the Columbia River: Results from a three-dimensional fully coupled wave-current interaction model

Science.gov (United States)

Akan, Çiǧdem; Moghimi, Saeed; Özkan-Haller, H. Tuba; Osborne, John; Kurapov, Alexander

2017-07-01

Numerical simulations were performed using a 3-D ocean circulation model (ROMS) two-way coupled to a phase-averaged wave propagation model (SWAN), to expand our understanding of the dynamics of wave-current interactions at the Mouth of the Columbia River (MCR). First, model results are compared with water elevations, currents, temperature, salinity, and wave measurements obtained by the U.S. Army Corp of Engineers during the Mega-Transect Experiment in 2005. We then discuss the effects of the currents on the waves and vice versa. Results show that wave heights are intensified notably at the entrance of the mouth in the presence of the tidal currents, especially in ebb flows. We also find nonlocal modifications to the wave field because of wave focusing processes that redirect wave energy toward the inlet mouth from adjacent areas, resulting in the presence of a tidal signatures in areas where local currents are weak. The model also suggests significant wave amplification at the edge of the expanding plume in the later stages of ebb, some tens of kilometers offshore of the inlet mouth, with potential implications for navigation safety. The effect of waves on the location of the plume is also analyzed, and results suggest that the plume is shifted in the down-wave direction when wave effects are considered, and that this shift is more pronounced for larger waves, and consistent with the presence of alongshore advection terms in the salt advection equation, which are related to the Stokes velocities associated with waves.

A Comparative Study of Voltage, Peak Current and Dual Current Mode Control Methods for Noninverting Buck-Boost Converter

Directory of Open Access Journals (Sweden)

M. Č. Bošković

2016-06-01

Full Text Available This paper presents a comparison of voltage mode control (VMC and two current mode control (CMC methods of noninverting buck-boost converter. The converter control-to-output transfer function, line-to-output transfer function and the output impedance are obtained for all methods by averaging converter equations over one switching period and applying small-signal linearization. The obtained results are required for the design procedure of feedback compensator to keep a system stable and robust. A comparative study of VMC, peak current mode control (PCMC and dual-current mode control (DCMC is performed. Performance evaluation of the closed-loop system with obtained compensator between these methods is performed via numerical simulations.

Current distribution tomography for determination of internal current density distributions

International Nuclear Information System (INIS)

Gailey, P.C.

1993-01-01

A method is presented for determination of current densities inside a cylindrical object using measurements of the magnetic fields outside the object. The cross section of the object is discretized with the current assumed constant over each defined region. Magnetic fields outside the object are related to the internal current densities through a geometry matrix which can be inverted to yield a solution for the current densities in terms of the measured fields. The primary limitation of this technique results from singularities in the geometry matrix that arise due to cylindrical symmetry of the problem. Methods for circumventing the singularities to obtain information about the distribution of current densities are discussed. This process of current distribution tomography is designed to determine internal body current densities using measurements of the external magnetic field distribution. It is non-invasive, and relatively simple to implement. Although related to a more general study of magnetic imaging which has been used to investigate endogenous currents in the brain and other parts of the body, it is restricted to currents either applied directly or induced by exposure to an external field. The research is related to public concern about the possibility of health effects resulting from exposure to power frequency electric and magnetic fields

Preliminary observations and results obtained with the ultraviolet spectrometer and polarimeter

International Nuclear Information System (INIS)

Tandberg-Hanssen, E.; Athay, R.G.; Beckers, J.M.; Brandt, J.C.; Bruner, E.C.; Chapman, R.D.; Cheng, C.C.; Burman, J.G.; Henze, W.; Hyder, C.L.; Michalitsianos, A.G.; Shine, R.A.; Schoolman, S.A.; Woodgate, B.E.

1981-01-01

We present new observations with the Ultraviolet Spectrometer and Polarimeter (UVSP) of a number of manifestations of solar activity obtained during the first 3 months of Solar Maximum Mission operations

Obtaining of Solids With Potential Corrosion Inhibitory Effects by Electrocoagulation Vinasse Methods

Directory of Open Access Journals (Sweden)

Dra. Elaine Ojeda-Armaignac

2015-11-01

Full Text Available In this paper, electrocoagulation experiments are performed at different vinasse samples with a viewto obtaining solids with potential corrosion inhibitory effects. Experimental tests were performed with samples of complex sugar «Argeo Martínez» Guantánamo province, «Urbano Noris Holguín province, in the antique complex Destillery-Brewery «Hatuey» of the province of Santiago de Cuba and in the rum factory of Appleton» in Kingston Jamaica. Electrocoagulation preliminary tests performed with the vinasse from distilleries of Santiago de Cuba, Guantánamo and Holguín allowed the definition of thevariables and their domain, which were considered in the design of experiments to obtain the most favorable conditions of operation. Preliminary experiments corroborated that increasing the current density and pH, increase linearly solids obtained and current density values exceeding 0,194 5 A/cm2 are not feasible because they increase the energy consumption process and the increase of solids is negligible. Validation of electrocoagulation method was demonstrated with results of the experimentaldesign from Jamaica´s vinasse, that were similar to those obtained with Cuban vinasse; reaching favorable conditions for operation at current density of 0,194 5/cm2, pH equal to 8,97 and time 5,6 min, resulting in 15,42 g of total solids for a minimum consumption of 8,44 kW·h/kg.

Test results of fault current limiter using YBCO tapes with shunt protection

Energy Technology Data Exchange (ETDEWEB)

Baldan, Carlos A; Lamas, Jerika S; Shigue, Carlos Y [Escola de Engenharia de Lorena, EEL USP, Lorena - SP (Brazil); Filho, Ernesto Ruppert, E-mail: cabaldan@gmail.co [Faculdade de Engenharia Eletrica, FEEC Unicamp, Campinas - SP (Brazil)

2010-06-01

A Fault Current Limiter (FCL) based on high temperature superconducting elements with four tapes in parallel were designed and tested in 220 V line for a fault current peak between 1 kA to 4 kA. The elements employed second generation (2G) HTS tapes of YBCO coated conductor with stainless steel reinforcement. The tapes were electrically connected in parallel with effective length of 0.4 m per element (16 elements connected in series) constituting a single-phase unit. The FCL performance was evaluated through over-current tests and its recovery characteristics under load current were analyzed using optimized value of the shunt protection. The projected limiting ratio achieved a factor higher than 4 during fault of 5 cycles without degradation. Construction details and further test results will be shown in the paper.

Investigating discrimination model of the signals obtained by eddy current testing

International Nuclear Information System (INIS)

Wache, G.; Rivenez, J.

1986-01-01

A software using an eddy current system controlled by a desk computer has been developed in order to separate a characteristic physical value among several parts. The numerical process involved uses multiparameter measurements done previously on significant parts belonging to the same class. The analysis presented deals with hardness testing of steel bolts in relation with heat-treatment, but other applications dealing with either micro structure check or defect investigation, could be done in the future by using a similar method

Operating results obtained in a nuclear power plant with a sensor surveillance prototype

International Nuclear Information System (INIS)

Jacquot, J.P.; Poujol, A.; Beaubatie, J.; Ciaramitaro, W.

1983-03-01

Surveillance methods have been validated and specific equipment have been built to measure the response time of sensors from a nuclear power plant protection channel. The reason of the choice of this parameter is twofold: the sensor response time is representative of the sensor physical status and is also part of the overall channel response time. Two surveillance methods are used: noise analysis (by AR or PSD modeling), and loop current step response (for resistance thermometer detectors only). The methods were validated on test facilities and on nuclear power plants. Two test equipments were built and tested on plants. Results are represented and conclusions are drawn on the feasibility of such methods for sensor surveillance [fr

The effect of uncertainty of reactor parameters obtained using k0-NAA on result of analysis

International Nuclear Information System (INIS)

Sasajima, Fumio

2006-01-01

Neutron Activation Analysis using the k 0 method is a useful method allowing convenient and accurate simultaneous analysis of plural elements, eliminating the need for the use of comparative reference samples. As already well known, it is essential for the correct result of an analysis to obtain the α-factor and f-factor for a neutron spectrum in an irradiation field accurately when an attempt is made to use the k 0 method. For this reason, based on data obtained from the experiment conducted in the JRR-3 PN-3 system, how uncertainty of the measured values for α-factor and f-factor affects the result of an analysis was evaluated. The process of evaluation involved intentionally varying the values for reactor parameters followed by making an analysis of environmental reference samples (NIST SRM-1632c) using the k 0 method to examine the effect of these factors on the concentrations of 19 elements. The result of the evaluation revealed that the degree of the effect of uncertainty on the concentrations of 19 elements was at best approx. 1% under the condition of this experiment assuming that the factor α, a reactor parameter, had uncertainty of approx. 200%. (author)

Results obtained with the passive radiation detectors in the ICCHIBAN-4 experiment

International Nuclear Information System (INIS)

Bilski, P.; Horwacik, T.

2005-05-01

In frame of the InterComparison of Cosmic rays with Heavy Ions Beams at NIRS (ICCHIBAN) organized at the HIMAC accelerator in Chiba several types of the thermoluminescent detectors (TLD), as well as CR-39 track detectors, were exposed. Four different types of TLDs were used: MTS-7 ( 7 LiF:Mg,Ti), MTS-6 ( 6 LiF:Mg,Ti), MCP-7 ( 7 LiF:Mg,Cu,P) and MTT-7 ( 7 LiF:Mg,Ti with changed activator composition. All TLDs were manufactured at the Institute of Nuclear Physics (INP) in Cracow. The detectors were irradiated with various doses of He, C, Ne and Fe ions. Part of exposures were done in unknown conditions, to test measuring capabilities of the detectors. For analyses of these results, the method of obtaining information on ionisation density of an unknown radiation field, which is based on ratios of responses of different LiF detectors, was successfully used. (author)

Current-current correlation function in presence of chemical potential and external magnetic field

International Nuclear Information System (INIS)

Apresyan, E.A.

2017-01-01

The (2+1)-dimensional electron system was observed, where relation between the Green functions and conductivity was used. The current-current correlation function Π_μ_ν(B) for the fermion system was calculated in presence of non-quantizing magnetic field B, chemical potential η and gap m. From this function it is possible to obtain the equation for polarization operator calculated without the magnetic field. The result is also applicable for graphene

Cross sections for neutrino and antineutrino neutral current interactions

International Nuclear Information System (INIS)

Bosetti, P.C.; Deden, H.; Deutschmann, M.; Fritze, P.; Graessler, H.; Hasert, F.J.; Morfin, J.; Schulte, R.; Schultze, K.; Seyfert, H.; Banerjee, S.; Barnham, K.W.J.; Beuselinck, R.; Butterworth, I.; Clayton, E.F.; Miller, D.B.; Powell, K.J.; Davis, C.L.; Grossman, P.; McGow, R.; Mulvey, J.H.; Myatt, G.; Perkins, D.H.; Pons, R.; Radojicic, O.; Renton, P.; Saitta, B.; Stenger, V.

1978-01-01

The cross sections for γ and anti γ neutral current interactions for which the hadron energy is > 15 GeV have been measured. These results, and the ratios of neutral current to charged current sections, are in agreement with the Weinberg-Salam model. Values of sin 2 thetasub(w) have been obtained both with and without the use of a parametrisation for the hadronic part of the interaction; the values are in good agreement with each other and the preferred result, that obtained by the method independent of hadronic models, is sin 2 thetasub(w) = 0.22 +- 0.05. (Auth.)

'Leak Current' correction for critical current measurement of no-insulation HTS coil

Energy Technology Data Exchange (ETDEWEB)

Song, Jung Bin [Laboratoire National des Champs Magnétiques Intenses, CNRS, Grenoble (France); Hahn, Seung Yong [Dept. of Electrical and Computer Engineering, Seoul National University, Seoul (Korea, Republic of)

2017-06-15

Discrepancy between a power supply current and an actual “spiral” coil current makes the conventional 4-probe measurement of a critical current (I{sub c}) of a no-insulation (NI) high temperature superconductor (HTS) coil inaccurate and time-consuming. This paper presents a fast and accurate approach for I{sub c} measurement of NI HTS coils. With an NI HTS coil energized at a constant ramping rate, a complete analytic expression for the spiral coil current was obtained from a first-order partial differential equation that derived from an equivalent circuit model of the NI coil. From the analytic solution, both spiral coil current and radial leak current can be obtained simultaneously, which enables fast and accurate measurement of the NI coil I{sub c}. To verify the proposed approach, an NI double-pancake (DP) coil, wound with GdBCO tapes of 6 mm × 0.1 mm, was constructed and its Ic was repeatedly measured with various ramping rates in a bath of liquid nitrogen at 77 K. The measured results agreed well with the calculated ones, which validates the proposed approach to measure I{sub c} of an NI HTS coil.

The heat current density correlation function: sum rules and thermal conductivity

International Nuclear Information System (INIS)

Singh, Shaminder; Tankeshwar, K; Pathak, K N; Ranganathan, S

2006-01-01

Expressions for the second and fourth sum rules of the heat current density correlation function have been derived in an appropriate ensemble. The thermal conductivity of Lennard-Jones fluids has been calculated using these sum rules for the heat current density correlation function and the Gaussian form of the memory function. It is found that the results obtained for the thermal conductivity are in good agreement with the molecular dynamics simulation results over a wide range of densities and temperatures. Earlier results obtained using the energy current density correlation function are also discussed

The heat current density correlation function: sum rules and thermal conductivity

Energy Technology Data Exchange (ETDEWEB)

Singh, Shaminder [Department of Physics, Panjab University, Chandigarh-160 014 (India); Tankeshwar, K [Department of Physics, Panjab University, Chandigarh-160 014 (India); Pathak, K N [Department of Physics, Panjab University, Chandigarh-160 014 (India); Ranganathan, S [Department of Physics, Royal Military College, Kingston, ON, K7K 7B4 (Canada)

2006-02-01

Expressions for the second and fourth sum rules of the heat current density correlation function have been derived in an appropriate ensemble. The thermal conductivity of Lennard-Jones fluids has been calculated using these sum rules for the heat current density correlation function and the Gaussian form of the memory function. It is found that the results obtained for the thermal conductivity are in good agreement with the molecular dynamics simulation results over a wide range of densities and temperatures. Earlier results obtained using the energy current density correlation function are also discussed.

Brief review of topmost scientific results obtained in 2016 at the Joint Institute for Nuclear Research

International Nuclear Information System (INIS)

Kravchenko, E.I.; Sabaeva, E.V.

2017-01-01

This brief review presents the topmost scientific results obtained in 2016 at the Joint Institute for Nuclear Research in such fields as theoretical and experimental physics, radiation and radiobiological research, accelerators, information technology and computer physics. It also provides information about the publications by JINR staff members and activities carried out at the JINR University Centre in 2016. [ru

Thermal domains in inhomogeneous current-carrying superconductors. Current-voltage characteriscs and dynamics of domain formation after current jumps

International Nuclear Information System (INIS)

Bezuglyj, A.I.; Shklovskij, V.A.

1984-01-01

The static and dynamic behavior of thermal domains in inhomogeneous superconducting films, where the inhomogeneity behaves like a portion of the film with a reduced critical current, have been studied theoretically within the framework of the phenomenological approach, using the heat balance equation and the dependence of the superconductor critical current on temperature. Depending on the size of the inhomogeneity (local or extended) and on the relative values of parameters of the homogeneous and inhomogeneous regions, different types of current-voltage characteristics are obtained. The nonstationary problem of thermal domain formation near the inhomogeneity after a current jump has been solved, and the domain boundary (kink) dynamics at a distance from the inhomogeneity has been analyzed. A combination of the results allows one to describe the whole process of normal phase formation and its spread throughout the superconducting film

High current density ion beam measurement techniques

International Nuclear Information System (INIS)

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

First results on fast wave current drive in advanced tokamak discharges in DIII-D

International Nuclear Information System (INIS)

Prater, R.; Cary, W.P.; Baity, F.W.

1995-07-01

Initial experiments have been performed on the DIII-D tokamak on coupling, direct electron heating, and current drive by fast waves in advanced tokamak discharges. These experiments showed efficient central heating and current drive in agreement with theory in magnitude and profile. Extrapolating these results to temperature characteristic of a power plant (25 keV) gives current drive efficiency of about 0.3 MA/m 2

Photoemission in nanosecond and picosecond regimes obtained from macro and micro cathodes

International Nuclear Information System (INIS)

Boussoukaya, M.; Bergeret, H.; Chehab, R.; Leblond, B.; Franco, M.

1987-03-01

For Lasertron studies at LAL, results obtained from tests on different photocathodes are given below. Using respectively two Nd: YAG lasers (a nanosecond one and a picosecond one) we have determined the level and the intensity of pulsed photoemission and the photoelectric yield in UV, green and infrared lights. We obtained a total current of more than 1 A with nanosecond width from a single W needle, and photoconversion yield of more than 1 was reached in green and UV lights. In classical pulsed photoemission, obtained photoconversion yield from LaB 6 photocathode was of about 10 -3 in higher fields

New high-definition thickness data obtained at tropical glaciers: preliminary results from Antisana volcano (Ecuador) using GPR prospection

Science.gov (United States)

Zapata, Camilo; Andrade, Daniel; Córdova, Jorge; Maisincho, Luis; Carvajal, Juan; Calispa, Marlon; Villacís, Marcos

2014-05-01

The study of tropical glaciers has been a significant contribution to the understanding of glacier dynamics and climate change. Much of the data and results have been obtained by analyzing plan-view images obtained by air- and space-borne sensors, as well as depth data obtained by diverse methodologies at selected points on the glacier surface. However, the measurement of glacier thicknesses has remained an elusive task in tropical glaciers, often located in rough terrains where the application of geophysical surveys (i.e. seismic surveys) requires logistics sometimes hardly justified by the amount of obtained data. In the case of Ecuador, however, where most glaciers have developed on active volcanoes and represent sources/reservoirs of fresh water, the precise knowledge of such information is fundamental for scientific research but also in order to better assess key aspects for the society. The relatively recent but fast development of the GPR technology has helped to obtain new highdefinition thickness data at Antisana volcano that will be used to: 1) better understand the dynamics and fate of tropical glaciers; 2) better estimate the amount of fresh water stored in the glaciers; 3) better assess the hazards associated with the sudden widespread melting of glaciers during volcanic eruptions. The measurements have been obtained at glaciers 12 and 15 of Antisana volcano, with the help of a commercial GPR equipped with a 25 MHz antenna. A total of 30 transects have been obtained, covering a distance of more than 3 km, from the glacier ablation zone, located at ~ 4600 masl, up to the level of 5200 masl. The preliminary results show a positive correlation between altitude and glacier thickness, with maximum and minimum calculated values reaching up to 80 m, and down to 15 m, respectively. The experience gained at Antisana volcano will be used to prepare a more widespread GPR survey in the glaciers of Cotopaxi volcano, whose implications in terms of volcanic hazards

Current-current interaction picture for proton-proton scattering

International Nuclear Information System (INIS)

Clarke, D.J.; Lo, S.Y.

1979-01-01

The authors propose that color current - color current interaction is reponsible for small angle elastic proton proton scattering at asymptotic energy. Excellent fits are obtained for all data above 12 GeV/c which covers twelve orders of magnitude

Enhanced performance on high current discharges in JET produced by ICRF heating during the current rise

International Nuclear Information System (INIS)

Bures, M.; Bhatnagar, V.; Cotrell, G.; Corti, S.; Christiansen, J.P.; Hellsten, T.; Jacquinot, J.; Lallia, P.; Lomas, P.; O'Rourke, J.; Taroni, A.; Tibone, F.; Start, D.F.H.

1989-01-01

The performance of high current discharges can be increased by applying central ICRF heating before or shortly after the onset of sawtooth activity in the plasma current rise phase. Sawtooth-free periods have been obtained resulting in the enhanced discharge performance. High T e (0) 9 - 10.5 keV with peaked profiles T e (0)/ e > = 3 - 4 were obtained giving values of n e (0)T e (0) up to 6x10 20 (keV m -3 ). Improvements in T i (0) and neutron production are observed. A 60 % enhancement in D-D reaction rate from 2nd harmonic deuterium (2ω CD ) heating appears to be present. In all current rise (CR) discharges radiation amounts to 25-50 % of total power. (author) 4 refs., 6 figs

Immobilized cell technology in beer brewing: Current experience and results

Directory of Open Access Journals (Sweden)

Leskošek-Čukalov Ida J.

2005-01-01

Full Text Available Immobilized cell technology (ICT has been attracting continual attention in the brewing industry over the past 30 years. Some of the reasons are: faster fermentation rates and increased volumetric productivity, compared to those of traditional beer production based on freely suspended cells, as well as the possibility of continuous operation. Nowadays, ICT technology is well established in secondary fermentation and alcohol- free and low-alcohol beer production. In main fermentation, the situation is more complex and this process is still under scrutiny on both the lab and pilot levels. The paper outlines the most important ICT processes developed for beer brewing and provides an overview of carrier materials, bioreactor design and examples of their industrial applications, as well as some recent results obtained by our research group. We investigated the possible applications of polyvinyl alcohol in the form of LentiKats®, as a potential porous matrices carrier for beer fermentation. Given are the results of growth studies of immobilized brewer's yeast Saccharomyces uvarum and the kinetic parameters obtained by using alginate microbeads with immobilized yeast cells and suspension of yeast cells as controls. The results indicate that the immobilization procedure in LentiKat® carriers has a negligible effect on cell viability and growth. The apparent specific growth rate of cells released in medium was comparable to that of freely suspended cells, implying preserved cell vitality. A series of batch fermentations performed in shaken flasks and an air-lift bioreactor indicated that the immobilized cells retained high fermentation activity. The full attenuation in green beer was reached after 48 hours in shaken flasks and less than 24 hours of fermentation in gas-lift bioreactors.

Brief review of topmost scientific results obtained in 2015 at the Joint Institute for Nuclear Research

International Nuclear Information System (INIS)

Sabaeva, E.V.; Krupko, E.I.

2016-01-01

This brief review presents the topmost scientific results obtained in 2015 at the Joint Institute for Nuclear Research in such fields as theoretical and experimental physics, radiation and radiobiological research, accelerators, information technology and computer physics. It also provides information about the publications by JINR staff members, awards given to JINR scientists, and activities carried out at the JINR University Centre in 2015. [ru

Brief review of topmost scientific results obtained in 2013 at the Joint Institute for Nuclear Research

International Nuclear Information System (INIS)

Sabaeva, E.V.; Kravchenko, E.I.

2014-01-01

This brief review presents the topmost scientific results obtained in 2013 at the Joint Institute for Nuclear Research in such areas as theoretical physics, experimental physics, radiation and radiobiological research, accelerators, information technology and computer physics. It also provides information on the number of publications by JINR staff members, awards given to JINR scientists, and activities carried out at the JINR University Centre in 2013.

Brief review of topmost scientific results obtained in 2014 at the Joint Institute for Nuclear Research

International Nuclear Information System (INIS)

Bulatova, V.V.; Sabaeva, E.V.

2015-01-01

This brief review presents the topmost scientific results obtained in 2014 at the Joint Institute for Nuclear Research in such fields as theoretical and experimental physics, radiation and radiobiological research, accelerators, information technology and computer physics. It also provides information about the publications by JINR staff members, patents for inventions, awards given to JINR scientists, and activities carried out at the JINR University Centre in 2014. [ru

The short-circuit test results of 6.9 kV/2.3 kV 400 kVA-class YBCO model transformer with fault current limiting function

International Nuclear Information System (INIS)

Tomioka, A.; Bohno, T.; Kakami, S.; Isozaki, M.; Watanabe, K.; Toyama, K.; Sugiyama, S.; Konno, M.; Gosho, Y.; Okamoto, H.; Hayashi, H.; Tsutsumi, T.; Iwakuma, M.; Saito, T.; Tanabe, K.; Shiohara, Y.

2013-01-01

Highlights: ► We manufactured the 400 kV A-class YBCO model transformer with FCL function. ► Short-circuit test was performed by applying 6.9 kV on primary side. ► The short-circuit current was limited to 174 A for a prospective current of 559 A. ► It agreed with the design and we also confirmed the I c did not degrade. ► The results suggest the possibility to design YBCO transformers with FCL function. -- Abstract: We are developing an elemental technology for 66/6.9 kV 20 MVA-class superconducting power transformer with fault current limiting function. In order to obtain the characteristics of YBCO conductor when the AC over current supplied to the conductor, the model coils were manufactured with YBCO tapes and tested. Based on these results, we manufactured the 6.9 kV/2.3 kV 400 kVA-class YBCO model transformer with fault current limiting function and performed short-circuit test. At the 0.25 s after short-circuit, the short-circuit current of primary winding was limited to about 174 A for a prospective current of 559 A. It was consistent with the design. The I–V characteristics of the winding did not change before and after the test. We consider the model transformer to be able to withstand AC over-current with the function of current limiting. The results suggest the possibility to design YBCO superconducting transformers with fault current limiting function for practical power grid

Current results from the Los Alamos CTX spheromak

Energy Technology Data Exchange (ETDEWEB)

Barnes, C.W.; Henins, I.; Hoida, H.W.; Jarboe, T.R.; Knox, S.O.; Linford, R.K.; Platts, D.A.; Sherwood, A.R.

1982-01-01

Continued discharge cleaning, improved vacuum practices, and optimized plasma formation operation have resulted in the CTX experiment achieving 1-ms plasma lifetimes with average temperatures of 20 to 40 eV. The major advance in operation has been the use of 5 to 20 mTorr H/sub 2/ gas fill. A multipoint Thomson scattering diagnostic with 12 radial positions yields radial profiles of temperature and densities, an example of which is shown. Local ..beta..'s can be determined from the measured pressure profile, and average values are typically 15 to 20%. In clean, long-lived discharges the density decreases at a more rapid rate than the magnetic field, until it reaches a value around 2 to 4 x 10/sup 13/ cm/sup -3/ where it remains constant. This is in contrast to the colder, radiation-dominated behavior, and is taken as evidence that the plasma ..beta.. is a limit to current operation in CTX.

Test result communication in primary care: a survey of current practice.

Science.gov (United States)

Litchfield, Ian; Bentham, Louise; Lilford, Richard; McManus, Richard J; Hill, Ann; Greenfield, Sheila

2015-11-01

The number of blood tests ordered in primary care continues to increase and the timely and appropriate communication of results remains essential. However, the testing and result communication process includes a number of participants in a variety of settings and is both complicated to manage and vulnerable to human error. In the UK, guidelines for the process are absent and research in this area is surprisingly scarce; so before we can begin to address potential areas of weakness there is a need to more precisely understand the strengths and weaknesses of current systems used by general practices and testing facilities. We conducted a telephone survey of practices across England to determine the methods of managing the testing and result communication process. In order to gain insight into the perspectives from staff at a large hospital laboratory we conducted paired interviews with senior managers, which we used to inform a service blueprint demonstrating the interaction between practices and laboratories and identifying potential sources of delay and failure. Staff at 80% of practices reported that the default method for communicating normal results required patients to telephone the practice and 40% of practices required that patients also call for abnormal results. Over 80% had no fail-safe system for ensuring that results had been returned to the practice from laboratories; practices would otherwise only be aware that results were missing or delayed when patients requested results. Persistent sources of missing results were identified by laboratory staff and included sample handling, misidentification of samples and the inefficient system for collating and resending misdirected results. The success of the current system relies on patients both to retrieve results and in so doing alert staff to missing and delayed results. Practices appear slow to adopt available technological solutions despite their potential for reducing the impact of recurring errors in the

MEASURING RESULTS NUMERAL TREATMENT OF IMPULSIVE CURRENTS BY MEANS OF ROGOVSKY BELT APPLICATION

Directory of Open Access Journals (Sweden)

U. Batygin

2009-01-01

Full Text Available The technique of numerical processing of measurement results of pulse currents by means of Rogovsky belt application is offered in the given work. It is shown that at measurement of signals by digital oscillographs and further numerical transformation of target signals, the possibilities of Rogovsky belt without the application of additional devices that in turn allows to define parameters of pulse currents with any peak-time characteristics essentially expand.

Non-inductive electric current generation with the Alfven waves

International Nuclear Information System (INIS)

Assis, A.S. de.

1988-01-01

Non-inductive current generation by means of radio frequency waves is studied using one-dimensional (1D) quasilinear equations. The main results obtained in this thesis are the general expressions for the current generated, for the efficiency of current generation and for the critical power - the lowest power required for current saturation. (M.W.O.) [pt

Pipeline inspection - failures selection and results obtained; Inspeccion interna de ductos - seleccion de fallas y resultados obtenidos

Energy Technology Data Exchange (ETDEWEB)

Motylicki, Juan Enrique [Oleoductos del Valle S.A. (OLDEVAL S.A.), (Argentina)

2003-07-01

The main objective of the pipelines maintenance is to assure the integrity of them in order to have a reliable operation and with an acceptable level of risk that minimizes the impact to people, to the environment and the business. The objective of this work is to expose the experiences obtained before by Oldelval and after the passages of the intelligent pig, carried out in the years 1999/2000. In the same one they will be described: How the flaws were selected to verify / to repair. Results obtained in digs. Laboratory studies to determine like they affect to the integrity of the pipeline, the different types of opposing plane defects. Conclusions. (author)

The earth's ring current - Present situation and future thrusts

Science.gov (United States)

Williams, D. J.

1987-01-01

Particle distributions, currents, and the ring current situation prior to the August 1984 launch of the AMPTE Charge Composition Explorer (CCE) are discussed. CCE results which demonstrate the capability of these new measurements to pursue questions of ring current sources, energization, and transport are presented. Consideration is given to various ring current generation mechanisms which have been discussed in the literature, and a two-step generation process which to a certain extent unifies the previous mechanisms is presented. The first in-situ global observations of ring current decay as obtained through the detection of energetic neutral atoms generated by charge exchange interactions between the ring current and hydrogen geocorona are discussed, as well as the possibility of using the detection of energetic neutral atoms to obtain global images of the earth's ring current.

Gender Diversity in Anesthesiology Programs: The Role of Current Residents and Department Leadership in the 2014 Match Results.

Science.gov (United States)

Kranner, Paul W; Mussehl, Denise A; Hess, Aaron S

2016-01-01

Nearly half of graduates of American medical colleges are women, yet the percentage of women entering accredited anesthesiology programs remains less than 40%. There are obviously many factors that influence the choice of a residency training program, from geography to reputation to the atmosphere, composition and camaraderie of the department. We examined whether a greater number of current female residents, a female Chair, or a female Program Director were associated with a program matching a greater number of female candidates in the 2014 NRMP Match. An electronic questionnaire was sent to all 132 ACGME-accredited anesthesiology programs immediately following the 2014 Match seeking information on the gender mix of their current residents, the gender of the Chair and Program Director, and the gender composition of their newly-matched candidates. The percentage of current female residents was significantly associated with the percentage of incoming female residents (p = 0.013). There was no association between the percentage of new female residents obtained in the Match and the presence of a female Chair or Program Director. The results of the 2013 NRMP anesthesiology match indicate that programs with a higher proportion of female residents were able to sustain that diversity and successfully match a higher percentage of female candidates. No correlation was seen with Chair and Program Director gender, suggesting further work is needed to define the influence of female role models on female applicants' choice of anesthesiology residency programs.

Problem of construction of the operator of the electromagnetic current of a nucleus

International Nuclear Information System (INIS)

Korchin, A.Y.; Shebeko, A.V.

1984-01-01

The idea of R. G. Sachs [Phys. Rev. 74, 433 (1948)] in the phenomenological theory of exchange currents in nuclei is developed to obtain an expression for the Hamiltonian of a nucleus. An expression is obtained for the current which has the same isospin structure as the pion and seagull currents in the theory of meson exchange currents. Sachs' result follows for the case of point nucleons

Method of forecasting pollutant transfer in an aquifer initial results obtained in a sandy medium (Barp site, Gironde)

International Nuclear Information System (INIS)

Madoz-Escande, C.; Peyrus, J.-C.

1979-01-01

Hydrogeological studies are undertaken in the context of the radiological safety of nuclear plants to forecast consequences of accidental releases of radioactive pollutants into an aquifer (transfer time, concentration at points of emergence). This quantitative forecast is obtained with the aid of a mathematical model with sequential emission. This requires a knowledge of the physical parameters of the aquifer and of the behavior of the pollutant in relation to the water-bearing medium. The physical parameters of a saturated porous medium are presented with the aid of radioactive tracer tests on a model and also in the field. The initial results obtained in a sandy medium are presented. In view of the difficulty of extrapolating to field conditions the conclusions of tests on models, it was necessary to set up a mobile laboratory with which in situ studies could be undertaken. The behavior of the pollutant in relation to the water-bearing medium is the subject of preliminary laboratory research on the laws of adsorption under different pH and temperature conditions. The numerical results obtained call for confirmation in the field. A description is given of a method which should enable the distribution coefficients to be evaluated in situ

Stability of a plasma filament with a skinned current

International Nuclear Information System (INIS)

Blekher, P.M.

1984-01-01

An effective sufficient condition of existence of ideal helical plasma filament instability in a strong longitUdinal magnetic field for skinned current profiles is deduced in the paper. The results of numerical calculations of current skinned profiles of instability diagrams are presented and these results are compared with the obtained sufficient condition. An analytical solution for one model current profile skinning and this solution also is compared with the sufficient condition of instability

Current-voltage characteristic of parallel-plane ionization chamber with inhomogeneous ionization

International Nuclear Information System (INIS)

Stoyanov, D G

2007-01-01

The balances of particles and charges in the volume of parallel-plane ionization chamber are considered. Differential equations describing the distribution of current densities in the chamber volume are obtained. As a result of the differential equations solution an analytical form of the current-voltage characteristic of parallel-plane ionization chamber with inhomogeneous ionization in the volume is obtained

Current-voltage characteristic of parallel-plane ionization chamber with inhomogeneous ionization

Energy Technology Data Exchange (ETDEWEB)

Stoyanov, D G [Faculty of Engineering and Pedagogy in Sliven, Technical University of Sofia, 59, Bourgasko Shaussee Blvd, 8800 Sliven (Bulgaria)

2007-08-15

The balances of particles and charges in the volume of parallel-plane ionization chamber are considered. Differential equations describing the distribution of current densities in the chamber volume are obtained. As a result of the differential equations solution an analytical form of the current-voltage characteristic of parallel-plane ionization chamber with inhomogeneous ionization in the volume is obtained.

Comparison of model results obtained with several European regional air quality models

NARCIS (Netherlands)

Hass, H.; Builtjes, P.J.H.; Simpson, D.; Stern, R.

1997-01-01

An intercomparison study has been performed with four photo-oxidant dispersion models (EMEP, EURAD, LOTOS and REM3) which are currently capable of performing photo-oxidant formation calculations over larger path of Europe. The models, in principle, were run in the mode in which they are normally

Summary of CDHS results on charged current in upsilon sup(-) -nucleon interactions

International Nuclear Information System (INIS)

Abramowicz, H.

1982-01-01

This short review includes results on cross sections up to 300 GeV, a test of Callan - Gross relation, the determination of structure functions of the nucleon and the limit on right handed currents contribution. Conclusions from tests of QCD and non asymptotically free theories for strong interactions are presented. (author)

Eddy current standards - Cracks versus notches

Science.gov (United States)

Hagemaier, D. J.; Collingwood, M. R.; Nguyen, K. H.

1992-10-01

Eddy current tests aimed at evaluating cracks and electron-discharge machined (EDM) notches in 7075-T6 aluminum specimens are described. A comparison of the shape and amplitude of recordings made from both transverse and longitudinal scans of small EDM notches and fatigue cracks showd almost identical results. The signal amplitude and phase angle increased with an increase of EDM notch and crak size. It is concluded that equivalent eddy current results obtained from similar-size surface cracks and notches in aluminum can be used to establish a desired sensitivity level for inspection.

Review of current results in computational studies of hydrocarbon phase and transport properties in nanoporous structures

Science.gov (United States)

Stroev, N.; Myasnikov, A.

2017-12-01

This article provides a general overview of the main simulation results on the behavior of gas/liquids under confinement conditions, namely hydrocarbons in shale formations, and current understanding of such phenomena. In addition to the key effects, which different research groups obtained and which have to be taken into account during the creation of reservoir simulation software, a list of methods is briefly covered. Comprehensive understanding of both fluid phase equilibrium and transport properties in nanoscale structures is of great importance for many scientific and technical disciplines, especially for petroleum engineering considering the hydrocarbon behavior in complex shale formations, the development of which increases with time. Recent estimations show that a significant amount of resources are trapped inside organic matter and clays, which has extremely low permeability and yet great economic potential. The issue is not only of practical importance, as the existing conventional approaches by definition are unable to capture complicated physics phenomena for effective results, but it is also of fundamental value. The research of the processes connected with such deposits is necessary for both evaluations of petroleum reservoir deposits and hydrodynamic simulators. That is why the review is divided into two major parts—equilibrium states of hydrocarbons and their transport properties in highly confined conditions.

Modeling of Pulsed Direct-Current Glow Discharge

International Nuclear Information System (INIS)

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.

Recent results from the HIT-II and HIT-SI helicity injection current drive experiments

International Nuclear Information System (INIS)

Jarboe, T.R.; Hamp, W.T.; Izzo, V.A.; Nelson, B.A.; O'Neill, R.G.; Raman, R.; Redd, A.J.; Sieck, P.E.; Smith, R.J.

2005-01-01

Three important results are reported. 1) CHI startup has produced 100 kA of closed current without using poloidal field (PF) coils or any transformer action. The initial equilibrium is then driven to 240 kA with a 3 V transformer loop voltage, indicating high quality plasma. 2) For the first time CHI alone has produced toroidal currents (350 kA) that far exceed q a I inj , and with I p /I tf as high as 1.2. The key to these new results appears to be having the toroidal field small enough that relaxation will occur. 3) The steady inductive helicity injection spheromak experiment has operated at 5 kHz for 6 ms with current amplitudes up to 11 kA in each injector. The helicity injection rate is nearly constant with the ExB flow always into the plasma and not into the walls. NIMROD simulations of HIT-SI show a buildup of spheromak fields. (author)

Computation of the current density in nonlinear materials subjected to large current pulses

International Nuclear Information System (INIS)

Hodgdon, M.L.; Hixson, R.S.; Parsons, W.M.

1991-01-01

This paper reports that the finite element method and the finite difference method are used to calculate the current distribution in two nonlinear conductors. The first conductor is a small ferromagnetic wire subjected to a current pulse that rises to 10,000 Amperes in 10 microseconds. Results from the transient thermal and transient magnetic solvers of the finite element code FLUX2D are used to compute the current density in the wire. The second conductor is a metal oxide varistor. Maxwell's equations, Ohm's law and the varistor relation for the resistivity and the current density of p = αj -β are used to derive a nonlinear differential equation. The solutions of the differential equation are obtained by a finite difference approximation and a shooting method. The behavior predicted by these calculations is in agreement with experiments

Eddy current analysis by BEM utilizing loop electric and surface magnetic currents as unknowns

International Nuclear Information System (INIS)

Ishibashi, Kazuhisa

2002-01-01

The surface integral equations whose unknowns are the surface electric and magnetic currents are widely used in eddy current analysis. However, when the skin depth is thick, computational error is increased especially in obtaining electromagnetic fields near the edge of the conductor. In order to obtain the electromagnetic field accurately, we propose an approach to solve surface integral equations utilizing loop electric and surface magnetic currents as unknowns. (Author)

Recent results on Tore Supra

International Nuclear Information System (INIS)

Moreau, D.

1995-01-01

Recent results regarding heating, confinement, current drive and profile modifications, heat and particle exhaust are reported. Improved core confinement is obtained after pellet injection (PEP) or Lower Hybrid current drive (LHEP) and may be linked with small - or reversed - central magnetic shear. Conversely, by increasing the magnetic shear in the gradient region, both LHCD and fast wave electron heating (FWEH) have produced improved global confinement was carried by the bootstrap current. Fast wave current drive has been observed at the level of 80 kA in a 0.4 MA discharge. In the ergodic divertor configuration, stable radiative layers were obtained with neon injection. At least 80% of a total of 7 MW injected power were radiated without confinement degradation or impurity accumulation. Finally, the heat exhaust capability of the various actively cooled plasma facing components is briefly described. (author) 14 refs.; 13 figs

Study on classical and excess eddy currents losses of Terfenol-D

Energy Technology Data Exchange (ETDEWEB)

Talebian, Soheil; Hojjat, Yousef [Department of Mechanical Engineering, Tarbiat Modares University, Tehran (Iran, Islamic Republic of); Ghodsi, Mojtaba [Department of Mechanical and Industrial Engineering, Sultan Qaboos University, Muscat (Oman); Karafi, Mohammad Reza [Department of Mechanical Engineering, Tarbiat Modares University, Tehran (Iran, Islamic Republic of)

2015-08-15

In the present paper, classical and excess eddy currents losses of Terfenol-D are studied and effects of magnetic field frequency, peak of magnetic flux density and diameter of Terfenol-D on the eddy currents losses are investigated. To provide reliable data for the purpose of the paper, an experimental laboratory is fabricated and used to obtain major and minor hysteresis loops of Terfenol-D at different frequencies. In theoretical study, initially an analytical model based on uniform distribution of magnetic flux is developed which yields to calculation of classical eddy currents losses. Then, another eddy currents model based on non-uniform distribution of magnetic flux and nonlinear diffusion of electromagnetic fields is presented. The difference between output values of the two models is identified as excess eddy currents losses. Obtained results show that the values of excess losses are generally larger than classical losses and applying just classical model leads to wrong calculation of actual value of eddy currents losses. For the results obtained from two above models, empirical models with respect to the magnetic field frequency and the peak value of magnetic flux density are achieved which can predict the eddy currents losses precisely. To validate the empirical relations, experiments are repeated at a new frequency and values of power losses calculated from analytical equations are compared with the predicted values of the empirical models. The results point towards possibility to use the obtained empirical relations in order to calculate the classical and excess eddy currents losses of Terfenol-D at the frequencies below 200 Hz and different values of magnetic flux density. - Highlights: • Classical eddy currents loss of Terfenol-D is studied using Maxwell's laws. • Excess eddy currents loss of Terfenol-D is studied using Mayergoyz nonlinear model. • Effects of Terfenol-D geometry on the eddy currents losses are investigated. • Power

Thermoelectric generator based on composites obtained by sintering of detonation nanodiamonds

Science.gov (United States)

Eidelman, E. D.; Meilakhs, A. P.; Semak, B. V.; Shakhov, F. M.

2017-11-01

A model of a thermoelectric generator is proposed, in which composite materials obtained by sintering diamond nanoparticles are used as the main component. To increase the useful conversion of heat into electric current, it is proposed to use the effect of electron drag by ballistic phonons. To reduce the ineffective heat spread, it is proposed to use the effect of thermal resistance of the boundaries between the graphite-like and diamond-like phases of the composite. An experimental confirmation of the existence of an optimal volume ratio between graphite-like and diamond-like phases of the composite is predicted and obtained. The highest achieved value of thermoelectric coefficient in the actual structure is 80 µV K-1 (which means 20 times increase compared to that of composites not of the optimal structure), with a thermal conductivity of 50 W m-1 K-1. These results were obtained with constant electrical conductivity. The combined influence of these two effects in case of the ideal composite structure should result in an increase of the thermoelectric efficiency parameter by three orders of magnitude.

The results obtained by INR-Pitesti to an international in-situ intercomparison exercise

International Nuclear Information System (INIS)

Dobrin, Relu; Dulama, Cristian; Toma, Alexandru

2008-01-01

Full text: The determination of soil contamination, dose rate measurements and in-situ gamma spectrometry are well established and widely used measurement procedures, especially after large scale nuclear incidents. To support decision makers and first responders with a more comprehensive and accurate overview immediately after a large scale nuclear or radiological emergency, as releases from a nuclear power plant or a terrorist attack with a dirty bomb, a fast and clear presentation of measurement data is indispensable. In 2007, the Austrian Research Centers GmbH - ARC (Seibersdorf) in cooperation with IAEA and the Austrian NBC Defense School organized an international measurement campaign, 'In-Situ Intercomparison Scenario' ISIS 2007, with the focus on In-Situ Gamma Spectrometry and Dose Rate Measurements in Emergency Situations. 56 teams from 25 countries, worldwide, took part to this exercise. The only Romanian team was 'CROWN'. The CROWN Laboratory is part of the Radiation Protection Laboratory of the Institute for Nuclear Research - Pitesti, certified for characterization of radioactive wastes and nuclear materials. The paper presents results obtained during different tasks of the exercise: 'Dose rate mapping'; 'Localization - Drive by'; 'Simulation of a contamination'; 'Identification Shielded; 'Identification/Quantification'; 'Buried sources; 'Environmental measurement'. (authors)

Comparison between dosimeter films and electronic dosimeters results obtained in F-18 production practices at IEN/CNEN

International Nuclear Information System (INIS)

Paulo, Osvaldir; Carlos, Luiz R.J.; Mendes, Milton

2008-01-01

Full text: The aim of the present work is the comparison of the dose rates values obtained from dosimeter films with the values obtained from electronic dosimeters used by radiological protection technician involved in practices with fluorine-18 production in CV-28 cyclotron at IEN/CNEN. The motivation for this work was the increase on the demand of this radiopharmaceutical. Nowadays there is an increase demand on the number of clinics and hospitals which had started to use the technique of radiodiagnostic using positron-emission tomography (PET). Therefore, the produced radionuclide activities (physics quantity) and also the complexity of the practices of radiological protection in the areas of that facility had increased a lot. The conventional statistical methods will be used to evaluate the results obtained in the analysis of the data obtained in the reading of the dosimeters. This comparative method is however a first step to taking decisions regarding radiological protection service. Therefore that the radiometric surveys of routine are taken in consideration, as well as the information from the technician of radiological protection that is working in those areas. All this data will give support to improve and implement methods and practices on the accelerators' facilities. In addition, the use of these electronic dosimeters will makes possible the technician read these dose rates received immediately during the practices and use these information you make decisions. In case of dose rates values to present above the expected the practice will be ploughed. Another point to be considered is that this work will propitiate the future updates of the procedures designated to those practices and to conduct at the radiological protection optimization. (author)

Vessel eddy current characteristics in SST-1 tokamak

Energy Technology Data Exchange (ETDEWEB)

Jana, Subrata; Pradhan, Subrata, E-mail: pradhan@ipr.res.in; Dhongde, Jasraj; Masand, Harish

2016-11-15

Highlights: • Eddy current distribution in the SST-1 vacuum vessel. • Circuit model analysis of eddy current. • A comparison of the field lines with and without the plasma column in identical conditions. • The influence of eddy current in magnetic NULL dynamics. - Abstract: Eddy current distribution in the vacuum vessel of the Steady state superconducting (SST-1) tokamak has been determined from the experimental data obtained using an array of internal voltage loops (flux loop) installed inside the vacuum vessel. A simple circuit model has been employed. The model takes into account the geometric and constructional features of SST-1 vacuum vessel. SST-1 vacuum vessel is a modified ‘D’ shaped vessel having major axis of 1.285 m and minor axis of 0.81 m and has been manufactured from non-magnetic stainless steel. The Plasma facing components installed inside the vacuum vessel are graphite blocks mounted on Copper Chromium Zirconium (CuCrZr) heat sink plates on inconel supports. During discharge of the central solenoid, eddy currents get generated in the vacuum vessel and passive supports on it. These eddy currents influence the early magnetic NULL dynamics and plasma break-down and start-up characteristics. The computed results obtained from the model have been benchmarked against experimental data obtained in large number of SST-1 plasma shots. The results are in good agreement. Once bench marked, the calculated eddy current based on flux loop signal and circuit equation model has been extended to the reconstruction of the overall B- field contours of SST-1 tokamak in the vessel region. A comparison of the field lines with and without the plasma column in identical conditions of the central solenoid and equilibrium field profiles has also been done with an aim to quantify the diagnostics responses in vacuum shots.

Experimental results obtained with the simulated cold moderator system. System characteristics and technical issues

CERN Document Server

Aso, T; Hino, R; Kaminaga, M; Kinoshita, H; Takahashi, T

2002-01-01

The Japan Atomic Energy Research Institute and the High Energy Accelerator Research Organization have been developing a Mega-Watt scale spallation target system. In the system, neutrons generated in a target are sorted out their energy to the proper values in liquid-hydrogen moderators. Then, the liquid-hydrogen is forced to circulate in order to suppress hydrogen temperature increase. In the operation of moderators, it is very important to establish a safety protection system against emergency shutdown of the accelerator or accidents of the cold moderator system. In order to obtain a technical data for design and safety review of the liquid-hydrogen system, we have fabricated an experimental apparatus simulated the cold moderator system using liquid nitrogen (max. 1.5 MPa, mini. 77 K) instead of liquid hydrogen. The experiments on a controllability of the system were carried out to investigate dynamic characteristics of the system. This report presents the experimental results and technical issues for the co...

Experimental Results Obtained with Air Liquide Cold Compression System CERN LHC and SNS Projects

CERN Document Server

Delcayre, F; Hamber, F; Hilbert, B; Monneret, E; Toia, J L

2006-01-01

Large scale collider facilities will make intensive use of superconducting magnets, operating below 2.0 K. This dictates high‐capacity refrigeration systems operating below 2.0 K. These systems, making use of cryogenic centrifugal compressors in a series arrangement with room temperature screw compressors will be coupled to a refrigerator, providing a certain power at 4.5 K. A first Air Liquide Cold Compression System (CCS) unit was built and delivered to CERN in 2001. Installed at the beginning of 2002, it was commissioned and tested successfully during year 2002. A series of four sets of identical CCS were then tested in 2004. Another set of four cryogenic centrifugal compressors (CCC) has been delivered to Thomas Jefferson National Accelerator Facility (JLAB) for the Spallation Neutron Source (SNS) in 2002. These compressors were tested and commissioned from December 2004 to July 2005. The experimental results obtained with these systems will be presented and discussed: the characteristics of the CCC wil...

The properties of chromium electrodeposited with programmed currents. Part II. Reversing current

Directory of Open Access Journals (Sweden)

TANJA M. KOSTIC

2000-01-01

Full Text Available The electrodeposition of chromium in programmed reversing current (RC, was investigated in the regime of high cathodic current density (77 A dm-2 and anodic current density (55 A dm-2. The ratio of the cathodic and anodic time (60 : 1 was used. Chromium was deposed on a steel substrate from a chromic-sulphuric acid solution, during one hour. Anode and cathode were suited in a system of parallel plates. Basic properties of deposits, like thickness, morphology, microhardness, brightness were examined. Surface distribution of the deposits was obtained from the measurements of the thicknesses of the deposits (between 32 and 67 µm. A ferromagnetic non-destructive method was used in the measurements. Based on the results, graphic models of deposit surface distribution were made. Two ranges of the thickness could be seen on the model (range 1 - average thickness 35.1 µm and range 2 - average thickness 57.81 µm. These results were statisticaly analysed by colums, rows and by the whole surface. For the whole specimens, the average thickness was 45.39 µm with a coefficient of variation of 0.2582. The basic properties of the deposits did not change with a variation of the thickness. Because of this, the coatings deposited with the reversing current could be much more considered reliable in wear and corrosion protection systems than ones deposited by direct current.

Dynamics and stabilization of peak current-mode controlled buck converter with constant current load

International Nuclear Information System (INIS)

Leng Min-Rui; Zhou Guo-Hua; Zhang Kai-Tun; Li Zhen-Hua

2015-01-01

The discrete iterative map model of peak current-mode controlled buck converter with constant current load (CCL), containing the output voltage feedback and ramp compensation, is established in this paper. Based on this model the complex dynamics of this converter is investigated by analyzing bifurcation diagrams and the Lyapunov exponent spectrum. The effects of ramp compensation and output voltage feedback on the stability of the converter are investigated. Experimental results verify the simulation and theoretical analysis. The stability boundary and chaos boundary are obtained under the theoretical conditions of period-doubling bifurcation and border collision. It is found that there are four operation regions in the peak current-mode controlled buck converter with CCL due to period-doubling bifurcation and border-collision bifurcation. Research results indicate that ramp compensation can extend the stable operation range and transfer the operating mode, and output voltage feedback can eventually eliminate the coexisting fast-slow scale instability. (paper)

Measurement results obtained from air quality monitoring system

Energy Technology Data Exchange (ETDEWEB)

Turzanski, P.K.; Beres, R. [Provincial Inspection of Environmental Protection, Cracow (Poland)

1995-12-31

An automatic system of air pollution monitoring operates in Cracow since 1991. The organization, assembling and start-up of the network is a result of joint efforts of the US Environmental Protection Agency and the Cracow environmental protection service. At present the automatic monitoring network is operated by the Provincial Inspection of Environmental Protection. There are in total seven stationary stations situated in Cracow to measure air pollution. These stations are supported continuously by one semi-mobile (transportable) station. It allows to modify periodically the area under investigation and therefore the 3-dimensional picture of creation and distribution of air pollutants within Cracow area could be more intelligible.

Aircrew Exposure To Cosmic Radiation Evaluated By Means Of Several Methods; Results Obtained In 2006

International Nuclear Information System (INIS)

Ploc, Ondrej; Spurny, Frantisek; Jadrnickova, Iva; Turek, Karel

2008-01-01

Routine evaluation of aircraft crew exposure to cosmic radiation in the Czech Republic is performed by means of calculation method. Measurements onboard aircraft work as a control tool of the routine method, as well as a possibility of comparison of results measured by means of several methods. The following methods were used in 2006: (1) mobile dosimetry unit (MDU) type Liulin--a spectrometer of energy deposited in Si-detector; (2) two types of LET spectrometers based on the chemically etched track detectors (TED); (3) two types of thermoluminescent detectors; and (4) two calculation methods. MDU represents currently one of the most reliable equipments for evaluation of the aircraft crew exposure to cosmic radiation. It is an active device which measures total energy depositions (E dep ) in the semiconductor unit, and, after appropriate calibration, is able to give a separate estimation for non-neutron and neutron-like components of H*(10). This contribution consists mostly of results acquired by means of this equipment; measurements with passive detectors and calculations are mentioned because of comparison. Reasonably good agreement of all data sets could be stated

Potential theory for stationary Schrödinger operators: a survey of results obtained with non-probabilistic methods

Directory of Open Access Journals (Sweden)

Marco Bramanti

1992-05-01

Full Text Available In this paper we deal with a uniformly elliptic operator of the kind: Lu  Au + Vu, where the principal part A is in divergence form, and V is a function assumed in a “Kato class”. This operator has been studied in different contexts, especially using probabilistic techniques. The aim of the present work is to give a unified and simplified presentation of the results obtained with non probabilistic methods for the operator L on a bounded Lipschitz domain. These results regard: continuity of the solutions of Lu=0; Harnack inequality; estimates on the Green's function and L-harmonic measure; boundary behavior of positive solutions of Lu=0, in particular a “Fatou's theorem”.

Magnetooscillations of the tunneling current between two-dimensional electron systems

International Nuclear Information System (INIS)

Raichev, O.E.; Vasko, F.T.

1995-08-01

We calculate electric current caused by electron tunnelling between two-dimensional layers in the magnetic field applied perpendicular to the layers. An elastic scattering of the electrons is taken into account. Analytical results are obtained for two regimes: i) small magnetic field, when the Landau quantization is suppressed by the scattering and the oscillatory part of the current shows nearly harmonic behaviour; ii) high magnetic field, when the Landau levels are well-defined and the conductivity shows series of sharp peaks corresponding to resonant magnetotunneling. In the last case, we used two alternative approaches: self-consistent Born approximation and path integral method, and compared obtained results. (author). 12 refs, 3 figs

Current efficiency in the chlorate cell process

Directory of Open Access Journals (Sweden)

Spasojević Miroslav D.

2014-01-01

Full Text Available A mathematical model has been set up for current efficiency in a chlorate cell acting as an ideal electrochemical tubular reactor with a linear increase in hypochlorite concentration from the entrance to the exit. Good agreement was found between the results on current efficiency experimentally obtained under simulated industrial chlorate production conditions and the theoretical values provided by the mathematical model. [Projekat Ministarstva nauke Republike Srbije, br. 172057 i br. 172062

Quantitative pulsed eddy current analysis

International Nuclear Information System (INIS)

Morris, R.A.

1975-01-01

The potential of pulsed eddy current testing for furnishing more information than conventional single-frequency eddy current methods has been known for some time. However, a fundamental problem has been analyzing the pulse shape with sufficient precision to produce accurate quantitative results. Accordingly, the primary goal of this investigation was to: demonstrate ways of digitizing the short pulses encountered in PEC testing, and to develop empirical analysis techniques that would predict some of the parameters (e.g., depth) of simple types of defect. This report describes a digitizing technique using a computer and either a conventional nuclear ADC or a fast transient analyzer; the computer software used to collect and analyze pulses; and some of the results obtained. (U.S.)

Programmable, very low noise current source

Science.gov (United States)

Scandurra, G.; Cannatà, G.; Giusi, G.; Ciofi, C.

2014-12-01

We propose a new approach for the realization of very low noise programmable current sources mainly intended for application in the field of low frequency noise measurements. The design is based on a low noise Junction Field Effect Transistor (JFET) acting as a high impedance current source and programmability is obtained by resorting to a low noise, programmable floating voltage source that allows to set the sourced current at the desired value. The floating voltage source is obtained by exploiting the properties of a standard photovoltaic MOSFET driver. Proper filtering and a control network employing super-capacitors allow to reduce the low frequency output noise to that due to the low noise JFET down to frequencies as low as 100 mHz while allowing, at the same time, to set the desired current by means of a standard DA converter with an accuracy better than 1%. A prototype of the system capable of supplying currents from a few hundreds of μA up to a few mA demonstrates the effectiveness of the approach we propose. When delivering a DC current of about 2 mA, the power spectral density of the current fluctuations at the output is found to be less than 25 pA/√Hz at 100 mHz and less than 6 pA/√Hz for f > 1 Hz, resulting in an RMS noise in the bandwidth from 0.1 to 10 Hz of less than 14 pA.

Fokker-Planck modeling of current penetration during electron cyclotron current drive

International Nuclear Information System (INIS)

Merkulov, A.; Westerhof, E.; Schueller, F. C.

2007-01-01

The current penetration during electron cyclotron current drive (ECCD) on the resistive time scale is studied with a Fokker-Planck simulation, which includes a model for the magnetic diffusion that determines the parallel electric field evolution. The existence of the synergy between the inductive electric field and EC driven current complicates the process of the current penetration and invalidates the standard method of calculation in which Ohm's law is simply approximated by j-j cd =σE. Here it is proposed to obtain at every time step a self-consistent approximation to the plasma resistivity from the Fokker-Planck code, which is then used in a concurrent calculation of the magnetic diffusion equation in order to obtain the inductive electric field at the next time step. A series of Fokker-Planck calculations including a self-consistent evolution of the inductive electric field has been performed. Both the ECCD power and the electron density have been varied, thus varying the well known nonlinearity parameter for ECCD P rf [MW/m -3 ]/n e 2 [10 19 m -3 ] [R. W. Harvey et al., Phys. Rev. Lett 62, 426 (1989)]. This parameter turns out also to be a good predictor of the synergetic effects. The results are then compared with the standard method of calculations of the current penetration using a transport code. At low values of the Harvey parameter, the standard method is in quantitative agreement with Fokker-Planck calculations. However, at high values of the Harvey parameter, synergy between ECCD and E parallel is found. In the case of cocurrent drive, this synergy leads to the generation of large amounts of nonthermal electrons and a concomitant increase of the electrical conductivity and current penetration time. In the case of countercurrent drive, the ECCD efficiency is suppressed by the synergy with E parallel while only a small amount of nonthermal electrons is produced

Enhanced performance of high current discharges in JET produced by ICRF heating during the current rise

International Nuclear Information System (INIS)

Bures, M.; Bhatnagar, V.; Christiansen, J.P.

1989-01-01

The performance of high current discharges can be improved by applying central ICRF heating before or shortly after the onset of sawtooth activity in the plasma current rise phase. Long sawtooth-free periods have been obtained which result in a transiently-enhanced discharge performance. High T c (0) = 9-10.5 keV with peaked profile T e (0)/ e > = 3-4 were obtained giving values of N e (0)T e (0) up to 6 x 10 20 (keV m -3 ). Improvements in T i (0) and neutron production are observed. A best value of n Dd (0)T i (0)τ E = 1.65 x 10 20 (m -3 keV s) was achieved. Local transport simulation shows that the electron and ion thermal diffusivities do not differ substantially in the two cases of current-rise (CR) and flat-top (FT) heating, the performance of the central plasma region being enhanced, in the case of current-rise, entirely by the elimination of the sawtooth instability. The maximum D-D reaction rate is enhanced by a factor of 2 compared to the flat-top value. An appreciable part of the reaction rate is attributed to 2nd harmonic deuterium (2ω CD ) heating. In all current-rise discharges radiation amounts to 25-50% of total power and Ζ eff remains roughly constant. (author)

Dark Current Measurements in GIF++

CERN Document Server

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.

Deposition By Turbidity Currents In Intraslope Diapiric Minibasins: Results Of 1-D Experiments And Numerical Modeling

Science.gov (United States)

Lamb, M.; Toniolo, H.; Parker, G.

2001-12-01

The slope of the continental margin of the northern Gulf of Mexico is riddled with small basins resulting from salt tectonics. Each such minibasin is the result of local subsidence due to salt withdrawal, and is isolated from neighboring basins by ridges formed due to compensational uplift. The minibasins are gradually filled by turbidity currents, which are active at low sea stand. Experiments in a 1-D minibasin reveal that a turbidity current flowing into a deep minibasin must undergo a hydraulic jump and form a muddy pond. This pond may not spill out of the basin even with continuous inflow. The reason for this is the detrainment of water across the settling interface that forms at the top of the muddy pond. Results of both experiments and numerical modeling of the flow and the evolution of the deposit are presented. The numerical model is the first of its kind to capture both the hydraulic jump and the effect of detrainment in ponded turbidity currents.

Quasi-equilibrium channel model of an constant current arc

Directory of Open Access Journals (Sweden)

Gerasimov Alexander V.

2003-01-01

Full Text Available The rather simple method of calculation of electronic and gas temperature in the channel of arc of plasma generator is offered. This method is based on self-consistent two-temperature channel model of an electric arc. The method proposed enables to obtain radial allocation of gas and electronic temperatures in a non-conducting zone of an constant current arc, for prescribed parameters of discharge (current intensity and power of the discharge, with enough good precision. The results obtained can be used in model and engineering calculations to estimate gas and electronic temperatures in the channel of an arc plasma generator.

Experimental Results Obtained with Air Liquide Cold Compression System: CERN LHC and SNS Projects

Science.gov (United States)

Delcayre, F.; Courty, J.-C.; Hamber, F.; Hilbert, B.; Monneret, E.; Toia, J.-L.

2006-04-01

Large scale collider facilities will make intensive use of superconducting magnets, operating below 2.0 K. This dictates high-capacity refrigeration systems operating below 2.0 K. These systems, making use of cryogenic centrifugal compressors in a series arrangement with room temperature screw compressors will be coupled to a refrigerator, providing a certain power at 4.5 K. A first Air Liquide Cold Compression System (CCS) unit was built and delivered to CERN in 2001. Installed at the beginning of 2002, it was commissioned and tested successfully during year 2002. A series of four sets of identical CCS were then tested in 2004. Another set of four cryogenic centrifugal compressors (CCC) has been delivered to Thomas Jefferson National Accelerator Facility (JLAB) for the Spallation Neutron Source (SNS) in 2002. These compressors were tested and commissioned from December 2004 to July 2005. The experimental results obtained with these systems will be presented and discussed: the characteristics of the CCC will be detailed. The principles of control for the CCC in series will be detailed.

Experimental results obtained with the simulated cold moderator system. System characteristics and technical issues

Energy Technology Data Exchange (ETDEWEB)

Aso, Tomokazu; Kaminaga, Masanori; Haga, Katsuhiro; Kinoshita, Hidetaka; Takahashi, Toshio; Hino, Ryutaro [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

2002-12-01

The Japan Atomic Energy Research Institute and the High Energy Accelerator Research Organization have been developing a Mega-Watt scale spallation target system. In the system, neutrons generated in a target are sorted out their energy to the proper values in liquid-hydrogen moderators. Then, the liquid-hydrogen is forced to circulate in order to suppress hydrogen temperature increase. In the operation of moderators, it is very important to establish a safety protection system against emergency shutdown of the accelerator or accidents of the cold moderator system. In order to obtain a technical data for design and safety review of the liquid-hydrogen system, we have fabricated an experimental apparatus simulated the cold moderator system using liquid nitrogen (max. 1.5 MPa, mini. 77 K) instead of liquid hydrogen. The experiments on a controllability of the system were carried out to investigate dynamic characteristics of the system. This report presents the experimental results and technical issues for the construction of a practical liquid-hydrogen moderator system of the Mega-Watt scale target system. (author)

Development and performance test results of 50 kA vapor-cooled current lead for ITER

International Nuclear Information System (INIS)

Sugimoto, Makoto; Isono, Takaaki; Hamada, Kazuya

1998-01-01

JAERI has developed 50 kA current leads for the International Thermonuclear Experimental Reactor (ITER). The Center Solenoid (CS) Model Coil program is under way by means of international collaboration in ITER-EDA. The CS model coil is being developed for ITER CS coil and is for demonstration for ITER construction. The performance test of the CS model coil will be carried out at the JAERI ITER common test facility (CTF). The current lead consists of the vertical lead and the connection lead. The vertical lead is a vapor-cooled type and has a cable-in-conduit geometry. The vertical lead was designed with a heat leak of 1.2 W/kA at a helium flow rate of 0.06 g/(s·kA). The measured heat leak satisfied the designed value. The connection lead was made from copper pipe soldered with NbTi superconducting wires. The pipe was stabilized by the superconducting wires and a cooling channel. The current lead was operated up to 60 kA. The design and the performance test results of 50 kA current leads are reported. The results meet the specifications for the CS model coil test and for the ITER real machine. (author)

The analysis of the survey results for the current 'business agent'

International Nuclear Information System (INIS)

Kim, I. H.; Shim, H. S.; Jeon, I. Y.; Kang, W. S.; Yun, K. H.; Na, S. H.; Park, T. J.; Kim, I. S.

2004-01-01

Our survey is conducted about the current systems in the 'Business Agents' regulations which prescribes running business such as the safe control of radiation on behalf of any permitted users. The radiation safety staffs who are engaged in the handling of radioisotope respond our quaternaries. They are as follows: 1. the radiation safety staffs' attitude to the need of 'Business Agent' regulations, 2. the satisfaction level of 'Business Agent' service, 3. the propriety of the manpower. The survey results are that the 68.4% of the respondents are in favor of the need of 'Business Agent' regulations and the 63.6% of the respondents expressed satisfactions for the service of 'Business Agent'. For the one manpower managing 'Business Agent', 32.3% of the respondents expressed as 'overburdened' and 37.5% as 'appropriate.' Our results give the feedback to develop the system of 'Business Agent' regulations as making feedback effect

Turbulent current layer equilibrium and current layer of the Earth magnetotail

International Nuclear Information System (INIS)

Antonova, E.E.; Ovchinnikov, I.L.

1996-01-01

Analysis of distribution of plasma and magnetic field concentration in the unidimensional current layer under the condition of equality of the current inflowing into the layer and the counter diffusion current by various dependences of the regular velocity and the turbulent diffusion coefficient on the magnetic field. Corresponding two-dimensional solutions are obtained in the tail approximation. Comparison of the model turbulent current layer with characteristics of the plasma layer of the Earth magnetosphere tail is carried out. 16 refs., 3 figs

Pregnancy does not affect HIV incidence test results obtained using the BED capture enzyme immunoassay or an antibody avidity assay.

Directory of Open Access Journals (Sweden)

Oliver Laeyendecker

2010-10-01

Full Text Available Accurate incidence estimates are needed for surveillance of the HIV epidemic. HIV surveillance occurs at maternal-child health clinics, but it is not known if pregnancy affects HIV incidence testing.We used the BED capture immunoassay (BED and an antibody avidity assay to test longitudinal samples from 51 HIV-infected Ugandan women infected with subtype A, C, D and intersubtype recombinant HIV who were enrolled in the HIVNET 012 trial (37 baseline samples collected near the time of delivery and 135 follow-up samples collected 3, 4 or 5 years later. Nineteen of 51 women were also pregnant at the time of one or more of the follow-up visits. The BED assay was performed according to the manufacturer's instructions. The avidity assay was performed using a Genetic Systems HIV-1/HIV-2 + O EIA using 0.1M diethylamine as the chaotropic agent.During the HIVNET 012 follow-up study, there was no difference in normalized optical density values (OD-n obtained with the BED assay or in the avidity test results (% when women were pregnant (n = 20 results compared to those obtained when women were not pregnant (n = 115; for BED: p = 0.9, generalized estimating equations model; for avidity: p = 0.7, Wilcoxon rank sum. In addition, BED and avidity results were almost exactly the same in longitudinal samples from the 18 women who were pregnant at only one study visit during the follow-up study (p = 0.6, paired t-test.These results from 51 Ugandan women suggest that any changes in the antibody response to HIV infection that occur during pregnancy are not sufficient to alter results obtained with the BED and avidity assays. Confirmation with larger studies and with other HIV subtypes is needed.

Comparison radiation dose of Z-axis automatic tube current modulation technique with fixed tube current multi-detector row CT scanning of lower extremity venography

International Nuclear Information System (INIS)

Yoo, Beong Gyu; Kweon, Dae Cheol; Lee, Jong Seok; Jang, Keun Jo; Jeon, Sang Hwan; Kim, Yong Soo

2007-01-01

Z-axis automatic tube current modulation technique automatically adjusts tube current based on size of body region scanned. The purpose of the current study was to compare noise, and radiation dose of Multi-Detector row CT (MDCT) of lower extremity performed with Z-axis modulation technique of automatic tube current modulation with manual selection fixed tube current. Fifty consecutive underwent MDCT venography of lower extremity with use of a MDCT scanner fixed tube current and Z-axis automatic tube current modulation technique (10, 11 and 12 HU noise index, 70∼450 mA). Scanning parameters included 120 kVp, 0.5 second gantry rotation time, 1.35:1 beam pitch, and 1 mm reconstructed section thickness. For each subject, images obtained with Z-axis modulation were compared with previous images obtained with fixed tube current (200, 250, 300 mA) and with other parameters identical. Images were compared for noise at five levels: iliac, femoral, popliteal, tibial, and peroneal vein of lower extremity. Tube current and gantry rotation time used for acquisitions at these levels were recorded. All CT examinations of study and control groups were diagnostically acceptable, though objective noise was significantly more with Z-axis automatic tube current modulation. Compared with fixed tube current, Z-axis modulation resulted in reduction of CTDIvol (range, -6.5%∼-35.6%) and DLP (range,-0.2%∼-20.2%). Compared with manually selected fixed tube current, Z-axis automatic tube current modulation resulted in reduced radiation dose at MDCT of lower extremity venography

Current results of the tandem mirror experiment

International Nuclear Information System (INIS)

Drake, R.P.

1980-01-01

The basic operating characteristics of the Tandem Mirror Experiment, (TMX) at the Lawrence Livermore Laboratory in the USA have been established. Tandem-mirror plasmas have been produced using neutral-beam-fueled end plugs and a gas-fueled center cell. An axial potential well between the end plugs has been measured. There is direct evidence that this potential well enhances the axial confinement of the center-cell ions. The observed densities and loss currents are consistent with preliminary studies of the particle sources and losses near the magnetic axis. The observed confinement is consistent with theory when plasma fluctuations are low. When the requirement of drift-cyclotron loss-cone mode stability is violated, the plasma fluctuations degrade the center-cell confinement

2D and 3D core-collapse supernovae simulation results obtained with the CHIMERA code

Energy Technology Data Exchange (ETDEWEB)

Bruenn, S W; Marronetti, P; Dirk, C J [Physics Department, Florida Atlantic University, 777 W. Glades Road, Boca Raton, FL 33431-0991 (United States); Mezzacappa, A; Hix, W R [Physics Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831-6354 (United States); Blondin, J M [Department of Physics, North Carolina State University, Raleigh, NC 27695-8202 (United States); Messer, O E B [Center for Computational Sciences, Oak Ridge National Laboratory, Oak Ridge, TN 37831-6354 (United States); Yoshida, S, E-mail: bruenn@fau.ed [Max-Planck-Institut fur Gravitationsphysik, Albert Einstein Institut, Golm (Germany)

2009-07-01

Much progress in realistic modeling of core-collapse supernovae has occurred recently through the availability of multi-teraflop machines and the increasing sophistication of supernova codes. These improvements are enabling simulations with enough realism that the explosion mechanism, long a mystery, may soon be delineated. We briefly describe the CHIMERA code, a supernova code we have developed to simulate core-collapse supernovae in 1, 2, and 3 spatial dimensions. We then describe the results of an ongoing suite of 2D simulations initiated from a 12, 15, 20, and 25 M{sub o-dot} progenitor. These have all exhibited explosions and are currently in the expanding phase with the shock at between 5,000 and 20,000 km. We also briefly describe an ongoing simulation in 3 spatial dimensions initiated from the 15 M{sub o-dot} progenitor.

A comparative analysis of the EEDF obtained by Regularization and by Least square fit methods

International Nuclear Information System (INIS)

Gutierrez T, C.; Flores Ll, H.

2004-01-01

The second derived of the characteristic curve current-voltage (I - V) of a Langmuir probe (I - V) is numerically calculated using the Tikhonov method for to determine the distribution function of the electrons energy (EEDF). One comparison of the obtained EEDF and a fit by least square are discussed (LS). The I - V experimental curve is obtained in a plasma source in the electron cyclotron resonance (ECR) using a cylindrical probe. The parameters of plasma are determined of the EEDF by means of the Laframboise theory. For the case of the LS fit, the obtained results are similar to those obtained by the Tikhonov method, but in the first case the procedure is slow to achieve the best fit. (Author)

Birkeland currents in the earth's magnetosphere

International Nuclear Information System (INIS)

Potemra, T.A.

1988-01-01

As a result of his polar expeditions at the beginning of this century, Kristian Birkeland determined that intense ionspheric currents were associated with the aurora. Birkeland suggested that these currents originated far from the Earth and that they flowed into and away from the polar atmosphere along the geomagnetic field lines. The existence of such field-aligned or Birkeland currents was disputed because it was not possible to unambiguously identify current systems that are field-aligned and those which are completely contained in the ionosphere with surface magnetic field observations. The presence of Birkeland currents has been absolutely confirmed with satellite-borne particle and magnetic field experiments conducted over the past two decades. These satellite observations have determined the large-scale patterns, flow directions, and intensities of Birkeland currents in the auroral and polar regions, and their relationship to the orientation and magnitude of the interplanetary magnetic field. The Birkeland currents are directly associated with visible and UV auroral forms observed with satellites. The results obtained from a variety of recently launched satellites are discussed here. These include Sweden's first satellite, VIKING, which has provided evidence for resonant Alfven waves on the same geomagnetic field lines that guide stationary Birkeland currents. These observations demonstrate the important role that these currents play in the coupling of energy between the interplanetary medium and the lower ionosphere and atmosphere

Paternity tests in Mexico: Results obtained in 3005 cases.

Science.gov (United States)

García-Aceves, M E; Romero Rentería, O; Díaz-Navarro, X X; Rangel-Villalobos, H

2018-04-01

National and international reports regarding the paternity testing activity scarcely include information from Mexico and other Latin American countries. Therefore, we report different results from the analysis of 3005 paternity cases analyzed during a period of five years in a Mexican paternity testing laboratory. Motherless tests were the most frequent (77.27%), followed by trio cases (20.70%); the remaining 2.04% included different cases of kinship reconstruction. The paternity exclusion rate was 29.58%, higher but into the range reported by the American Association of Blood Banks (average 24.12%). We detected 65 mutations, most of them involving one-step (93.8% and the remaining were two-step mutations (6.2%) thus, we were able to estimate the paternal mutation rate for 17 different STR loci: 0.0018 (95% CI 0.0005-0.0047). Five triallelic patterns and 12 suspected null alleles were detected during this period; however, re-amplification of these samples with a different Human Identification (HID) kit confirmed the homozygous genotypes, which suggests that most of these exclusions actually are one-step mutations. HID kits with ≥20 STRs detected more exclusions, diminishing the rate of inconclusive results with isolated exclusions (Powerplex 21 kit (20 STRs) and Powerplex Fusion kit (22 STRs) offered similar PI (p = 0.379) and average number of exclusions (PE) (p = 0.339) when a daughter was involved in motherless tests. In brief, besides to report forensic parameters from paternity tests in Mexico, results describe improvements to solve motherless paternity tests using HID kits with ≥20 STRs instead of one including 15 STRs. Copyright © 2018 Elsevier Ltd and Faculty of Forensic and Legal Medicine. All rights reserved.

Current-induced atomic dynamics, instabilities, and Raman signals

DEFF Research Database (Denmark)

Lu, Jing Tao; Brandbyge, Mads; Hedegard, Per

2012-01-01

We derive and employ a semiclassical Langevin equation obtained from path integrals to describe the ionic dynamics of a molecular junction in the presence of electrical current. The electronic environment serves as an effective nonequilibrium bath. The bath results in random forces describing Joule...... heating, current-induced forces including the nonconservative wind force, dissipative frictional forces, and an effective Lorentz-type force due to the Berry phase of the nonequilibrium electrons. Using a generic two-level molecular model, we highlight the importance of both current-induced forces...... and Joule heating for the stability of the system. We compare the impact of the different forces, and the wide-band approximation for the electronic structure on our result. We examine the current-induced instabilities (excitation of runaway "waterwheel" modes) and investigate the signature...

Microsecond ramp compression of a metallic liner driven by a 5 MA current on the SPHINX machine using a dynamic load current multiplier pulse shaping

Science.gov (United States)

d'Almeida, T.; Lassalle, F.; Morell, A.; Grunenwald, J.; Zucchini, F.; Loyen, A.; Maysonnave, T.; Chuvatin, A. S.

2013-09-01

SPHINX is a 6 MA, 1-μs Linear Transformer Driver (LTD) operated by the CEA Gramat (France) and primarily used for imploding Z-pinch loads for radiation effects studies. Among the options that are currently being evaluated to improve the generator performances are an upgrade to a 20 MA, 1-μs LTD machine and various power amplification schemes, including a compact Dynamic Load Current Multiplier (DLCM). A method for performing magnetic ramp compression experiments, without modifying the generator operation scheme, was developed using the DLCM to shape the initial current pulse in order to obtain the desired load current profile. In this paper, we discuss the overall configuration that was selected for these experiments, including the choice of a coaxial cylindrical geometry for the load and its return current electrode. We present both 3-D Magneto-hydrodynamic and 1D Lagrangian hydrodynamic simulations which helped guide the design of the experimental configuration. Initial results obtained over a set of experiments on an aluminium cylindrical liner, ramp-compressed to a peak pressure of 23 GPa, are presented and analyzed. Details of the electrical and laser Doppler interferometer setups used to monitor and diagnose the ramp compression experiments are provided. In particular, the configuration used to field both homodyne and heterodyne velocimetry diagnostics in the reduced access available within the liner's interior is described. Current profiles measured at various critical locations across the system, particularly the load current, enabled a comprehensive tracking of the current circulation and demonstrate adequate pulse shaping by the DLCM. The liner inner free surface velocity measurements obtained from the heterodyne velocimeter agree with the hydrocode results obtained using the measured load current as the input. An extensive hydrodynamic analysis is carried out to examine information such as pressure and particle velocity history profiles or magnetic

Microsecond ramp compression of a metallic liner driven by a 5 MA current on the SPHINX machine using a dynamic load current multiplier pulse shaping

Energy Technology Data Exchange (ETDEWEB)

D' Almeida, T.; Lassalle, F.; Morell, A.; Grunenwald, J.; Zucchini, F.; Loyen, A. [CEA, DAM, GRAMAT, F-46500 Gramat (France); Maysonnave, T. [International Technologies for High Pulsed Power, F-46500 Thégra (France); Chuvatin, A. S. [Laboratoire de Physique des Plasmas, Ecole Polytechnique, F-91128 Palaiseau (France)

2013-09-15

SPHINX is a 6 MA, 1-μs Linear Transformer Driver (LTD) operated by the CEA Gramat (France) and primarily used for imploding Z-pinch loads for radiation effects studies. Among the options that are currently being evaluated to improve the generator performances are an upgrade to a 20 MA, 1-μs LTD machine and various power amplification schemes, including a compact Dynamic Load Current Multiplier (DLCM). A method for performing magnetic ramp compression experiments, without modifying the generator operation scheme, was developed using the DLCM to shape the initial current pulse in order to obtain the desired load current profile. In this paper, we discuss the overall configuration that was selected for these experiments, including the choice of a coaxial cylindrical geometry for the load and its return current electrode. We present both 3-D Magneto-hydrodynamic and 1D Lagrangian hydrodynamic simulations which helped guide the design of the experimental configuration. Initial results obtained over a set of experiments on an aluminium cylindrical liner, ramp-compressed to a peak pressure of 23 GPa, are presented and analyzed. Details of the electrical and laser Doppler interferometer setups used to monitor and diagnose the ramp compression experiments are provided. In particular, the configuration used to field both homodyne and heterodyne velocimetry diagnostics in the reduced access available within the liner's interior is described. Current profiles measured at various critical locations across the system, particularly the load current, enabled a comprehensive tracking of the current circulation and demonstrate adequate pulse shaping by the DLCM. The liner inner free surface velocity measurements obtained from the heterodyne velocimeter agree with the hydrocode results obtained using the measured load current as the input. An extensive hydrodynamic analysis is carried out to examine information such as pressure and particle velocity history profiles or

Microsecond ramp compression of a metallic liner driven by a 5 MA current on the SPHINX machine using a dynamic load current multiplier pulse shaping

International Nuclear Information System (INIS)

D'Almeida, T.; Lassalle, F.; Morell, A.; Grunenwald, J.; Zucchini, F.; Loyen, A.; Maysonnave, T.; Chuvatin, A. S.

2013-01-01

SPHINX is a 6 MA, 1-μs Linear Transformer Driver (LTD) operated by the CEA Gramat (France) and primarily used for imploding Z-pinch loads for radiation effects studies. Among the options that are currently being evaluated to improve the generator performances are an upgrade to a 20 MA, 1-μs LTD machine and various power amplification schemes, including a compact Dynamic Load Current Multiplier (DLCM). A method for performing magnetic ramp compression experiments, without modifying the generator operation scheme, was developed using the DLCM to shape the initial current pulse in order to obtain the desired load current profile. In this paper, we discuss the overall configuration that was selected for these experiments, including the choice of a coaxial cylindrical geometry for the load and its return current electrode. We present both 3-D Magneto-hydrodynamic and 1D Lagrangian hydrodynamic simulations which helped guide the design of the experimental configuration. Initial results obtained over a set of experiments on an aluminium cylindrical liner, ramp-compressed to a peak pressure of 23 GPa, are presented and analyzed. Details of the electrical and laser Doppler interferometer setups used to monitor and diagnose the ramp compression experiments are provided. In particular, the configuration used to field both homodyne and heterodyne velocimetry diagnostics in the reduced access available within the liner's interior is described. Current profiles measured at various critical locations across the system, particularly the load current, enabled a comprehensive tracking of the current circulation and demonstrate adequate pulse shaping by the DLCM. The liner inner free surface velocity measurements obtained from the heterodyne velocimeter agree with the hydrocode results obtained using the measured load current as the input. An extensive hydrodynamic analysis is carried out to examine information such as pressure and particle velocity history profiles or magnetic

Non-dissipative currents in the theory of thermomagnetic properties of inversion layers

International Nuclear Information System (INIS)

Streda, P.; Oji, H.

1983-07-01

Starting from the Kubo formula, the non-dissipative electric and thermal currents are expressed as functions of thermodynamical quantities only. These currents originate from the surface currents which are responsible for the quantized Hall effect. The results are in full agreement with that, obtained from thermodynamical arguments. One-electron approximation is used. (author)

Unsupervised Classification of Surface Defects in Wire Rod Production Obtained by Eddy Current Sensors

Directory of Open Access Journals (Sweden)

Sergio Saludes-Rodil

2015-04-01

Full Text Available An unsupervised approach to classify surface defects in wire rod manufacturing is developed in this paper. The defects are extracted from an eddy current signal and classified using a clustering technique that uses the dynamic time warping distance as the dissimilarity measure. The new approach has been successfully tested using industrial data. It is shown that it outperforms other classification alternatives, such as the modified Fourier descriptors.

Operating results for the beam profile monitor system currently in use at Bevalac Facility

International Nuclear Information System (INIS)

Stover, G.; Fowler, K.

1987-03-01

Three stations of a soon to be completed multi-station, multi-wire beam monitoring system have been installed in the Bevalac transfer line. The following article will provide a cursory analysis of the electronic circuitry, discuss new design additions and summarize the operating results obtained over the last year

Current density profile inside q=1 on Tore Supra

International Nuclear Information System (INIS)

Joffrin, E.; Desgranges, C.; Sabot, R.; Dubois, M.A.

1995-01-01

The Tore Supra polarimeter used to measure the poloidal field distribution is described. The current density profiles are computed in two different ways using the interferometric and polarimetric data in conjunction with the magnetic data and the location of the inversion radius determined by the soft X-ray camera. The current density inside the q=1 surface is investigated for normal and monster sawteeth. Its variation are also measured by the polarimeter and compared with that predicted by the current diffusion equation assuming complete reconnection. Finally, the safety factor profile is compared with that obtained with the striation data of the pellet ablation. The results of the evolution of the q profile during sawteeth are in good agreement with those obtained in other devices. (author) 9 refs.; 4 figs

Current 2-μm dial measurements of atmospheric CO2 and expected results from space using new MCT APDS

Science.gov (United States)

Dumas, A.; Gibert, F.; Rothman, J.; Édouart, D.; Le Mounier, F.; Cénac, C.

2017-11-01

In the framework of CO2 monitoring in the Atmospheric Boundary Layer (ABL), a ground-based 2-μm Differential Absorption Lidar (DIAL) has been developed at the Laboratoire de Météorologie Dynamique (LMD) in Palaiseau. In order to derive flux information, this system has been set up with coherent detection, which allows to combine CO2 density measurements with wind velocity measurements. On the other hand, new advances in the field of Mercury Cadmium Tellure (MCT) Avalanche Photodiodes (APDs) open the way for high-precision measurements in direct detection ultimately from space. In this study, we first report on state of the art measurements obtained with the current coherent DIAL system before presenting expected results for a similar laser transmitter equipped with MCT APDs. For this latter part, we use a numerical model which relies on APDs performance data provided by the Laboratoire d'Électronique et de Technologie de l'Information (LETI).

Validation Test Results for Orthogonal Probe Eddy Current Thruster Inspection System

Science.gov (United States)

Wincheski, Russell A.

2007-01-01

Recent nondestructive evaluation efforts within NASA have focused on an inspection system for the detection of intergranular cracking originating in the relief radius of Primary Reaction Control System (PCRS) Thrusters. Of particular concern is deep cracking in this area which could lead to combustion leakage in the event of through wall cracking from the relief radius into an acoustic cavity of the combustion chamber. In order to reliably detect such defects while ensuring minimal false positives during inspection, the Orthogonal Probe Eddy Current (OPEC) system has been developed and an extensive validation study performed. This report describes the validation procedure, sample set, and inspection results as well as comparing validation flaws with the response from naturally occuring damage.

CONSIDERATION REGARDING CURRENT ASSETS IN THE CONSTRUCTION ENTITIES

Directory of Open Access Journals (Sweden)

Laura Adriana COJOCARU (ALIONESCU

2014-06-01

Full Text Available Accounting for current assets mainly aims to obtain useful information on the management of their best in order to make management decisions. Counting efficiency of these assets, their importance, provides improved performance of the entity. In this paper we want to study the degree of implementation of policies and accounting treatments on the current assets in the specific construction economic entities, the problems of implementation and thus better addressing their theoretical and procedural to improve the information provided by financial statements. Due to the importance of proper conduct of business owned entities, accounting current assets should result in optimal and efficient control of current assets.

Determination of averaged axisymmetric flow surfaces according to results obtained by numerical simulation of flow in turbomachinery

Directory of Open Access Journals (Sweden)

Bogdanović-Jovanović Jasmina B.

2012-01-01

Full Text Available In the increasing need for energy saving worldwide, the designing process of turbomachinery, as an essential part of thermal and hydroenergy systems, goes in the direction of enlarging efficiency. Therefore, the optimization of turbomachinery designing strongly affects the energy efficiency of the entire system. In the designing process of turbomachinery blade profiling, the model of axisymmetric fluid flows is commonly used in technical practice, even though this model suits only the profile cascades with infinite number of infinitely thin blades. The actual flow in turbomachinery profile cascades is not axisymmetric, and it can be fictively derived into the axisymmetric flow by averaging flow parameters in the blade passages according to the circular coordinate. Using numerical simulations of flow in turbomachinery runners, its operating parameters can be preliminarily determined. Furthermore, using the numerically obtained flow parameters in the blade passages, averaged axisymmetric flow surfaces in blade profile cascades can also be determined. The method of determination of averaged flow parameters and averaged meridian streamlines is presented in this paper, using the integral continuity equation for averaged flow parameters. With thus obtained results, every designer can be able to compare the obtained averaged flow surfaces with axisymmetric flow surfaces, as well as the specific work of elementary stages, which are used in the procedure of blade designing. Numerical simulations of flow in an exemplary axial flow pump, used as a part of the thermal power plant cooling system, were performed using Ansys CFX. [Projekat Ministarstva nauke Republike Srbije, br. TR33040: Revitalization of existing and designing new micro and mini hydropower plants (from 100 kW to 1000 kW in the territory of South and Southeast Serbia

Tidal current energy resource assessment in Ireland: Current status and future update

International Nuclear Information System (INIS)

O'Rourke, Fergal; Boyle, Fergal; Reynolds, Anthony

2010-01-01

Interest in renewable energy in Ireland has increased continually over the past decade. This interest is due primarily to security of supply issues and the effects of climate change. Ireland imports over 90% of its primary energy consumption, mostly in the form of fossil fuels. The exploitation of Ireland's vast indigenous renewable energy resources is required in order to reduce this over-dependence on fossil fuel imports to meet energy demand. Various targets have been set by the Irish government to incorporate renewable energy technologies into Ireland's energy market. As a result of these targets, the development in wind energy has increased substantially over the past decade; however this method of energy extraction is intermittent and unpredictable. Ireland has an excellent tidal current energy resource and the use of this resource will assist in the development of a sustainable energy future. Energy extraction using tidal current energy technologies offers a vast and predictable energy resource. This paper reviews the currently accepted tidal current energy resource assessment for Ireland. This assessment was compiled by Sustainable Energy Ireland in a report in 2004. The assessment employed a 2-dimensional numerical model of the tidal current velocities around Ireland, and from this numerical model the theoretical tidal current energy resource was identified. With the introduction of constraints and limitations, the technical, practical, accessible and viable tidal current energy resources were obtained. The paper discusses why the assessment needs updating including the effect on the assessment of the current stage of development of tidal current turbines and their deployment technology. (author)

Interobserver agreement of the injury diagnoses obtained by postmortem computed tomography of traffic fatality victims and a comparison with autopsy results

DEFF Research Database (Denmark)

Leth, Peter Mygind; Struckmann, Henrik; Lauritsen, Jens

2013-01-01

The present study investigated the interobserver variation between a radiologist and a forensic pathologist in 994 injury diagnoses obtained by postmortem computed tomography (CT) of 67 traffic fatality victims, and the results were compared with diagnoses obtained by autopsy. The injuries were...... system, but the pathologist diagnosed more organ injuries. We recommend the use of a radiologist as a consultant for the evaluation of postmortem CT images. Training in radiology should be included in forensic medicine postgraduate training. CT was superior to autopsy in detecting abnormal air...

Chiral current generation in QED by longitudinal photons

Energy Technology Data Exchange (ETDEWEB)

Acosta Avalo, J.L., E-mail: jlacosta@instec.cu [Instituto Superior de Tecnologías y Ciencias Aplicadas (INSTEC), Ave Salvador Allende, No. 1110, Vedado, La Habana 10400 (Cuba); Pérez Rojas, H., E-mail: hugo@icimaf.cu [Instituto de Cibernética, Matemática y Física (ICIMAF), Calle E esq 15, No. 309, Vedado, La Habana 10400 (Cuba)

2016-08-15

We report the generation of a pseudovector electric current having imbalanced chirality in an electron–positron strongly magnetized gas in QED. It propagates along the external applied magnetic field B as a chiral magnetic effect in QED. It is triggered by a perturbative electric field parallel to B, associated to a pseudovector longitudinal mode propagating along B. An electromagnetic chemical potential was introduced, but our results remain valid even when it vanishes. A nonzero fermion mass was assumed, which is usually considered vanishing in the literature. In the quantum field theory formalism at finite temperature and density, an anomaly relation for the axial current was found for a medium of massive fermions. It bears some analogy to the Adler–Bell–Jackiw anomaly. From the expression for the chiral current in terms of the photon self-energy tensor in a medium, it is obtained that electrons and positrons scattered by longitudinal photons (inside the light cone) contribute to the chiral current, as well as the to pair creation due to longitudinal photons (out of light cone). In the static limit, an electric pseudovector current is obtained in the lowest Landau level.

Chiral current generation in QED by longitudinal photons

Directory of Open Access Journals (Sweden)

J.L. Acosta Avalo

2016-08-01

Full Text Available We report the generation of a pseudovector electric current having imbalanced chirality in an electron–positron strongly magnetized gas in QED. It propagates along the external applied magnetic field B as a chiral magnetic effect in QED. It is triggered by a perturbative electric field parallel to B, associated to a pseudovector longitudinal mode propagating along B. An electromagnetic chemical potential was introduced, but our results remain valid even when it vanishes. A nonzero fermion mass was assumed, which is usually considered vanishing in the literature. In the quantum field theory formalism at finite temperature and density, an anomaly relation for the axial current was found for a medium of massive fermions. It bears some analogy to the Adler–Bell–Jackiw anomaly. From the expression for the chiral current in terms of the photon self-energy tensor in a medium, it is obtained that electrons and positrons scattered by longitudinal photons (inside the light cone contribute to the chiral current, as well as the to pair creation due to longitudinal photons (out of light cone. In the static limit, an electric pseudovector current is obtained in the lowest Landau level.

Tiling by rectangles and alternating current

KAUST Repository

Prasolov, M. V.

2011-04-01

This paper is on tilings of polygons by rectangles. A celebrated physical interpretation of such tilings by R.L. Brooks, C.A.B. Smith, A.H. Stone and W.T. Tutte uses direct-current circuits. The new approach of this paper is an application of alternating-current circuits. The following results are obtained: •a necessary condition for a rectangle to be tilable by rectangles of given shapes;•a criterion for a rectangle to be tilable by rectangles similar to it but not all homothetic to it;•a criterion for a "generic" polygon to be tilable by squares. These results generalize those of C. Freiling, R. Kenyon, M. Laczkovich, D. Rinne, and G. Szekeres. © 2010 Elsevier Inc.

Assessment of the French environment radiological status in 2009. Synthesis of the results obtained by the IRSN survey networks

International Nuclear Information System (INIS)

2009-01-01

After a brief recall of the IRSN's missions, this report describes why and how radioactivity is controlled in France. It presents the national network for environment radioactivity measurements, and indicates the objectives of this radiological survey. It comments the status and levels of the natural and artificial radioactivity in France, discusses the results of the territory general survey (atmosphere, inland, coast, regions), the results of fuel cycle related sites (nuclear sites, old mining sites, front end industries, electricity production plants, back end industries, waste storage sites), the results concerning the nuclear medicine radioactive releases, the results obtained during selective expertises, and discusses the assessment of the exposure of the French population to ionizing radiations. It finally indicates how those data are published

Nuclear power in the OECD countries results and current issues

International Nuclear Information System (INIS)

Jones, C.F.

1989-01-01

The first use of nuclear power for the generation of electricity on a commercial scale occurred in the United Kingdom in 1956. Today, 13 OECD countries have 318 nuclear units in operation and 66 more in construction or on order. This outstanding achievement is the result of the successful organization, start up, and operation of an industry to design, build, equip, fuel, and maintain these facilites. Nuclear power, however, is currently troubled by a number of issues that may impair its ability to reach its full potential. The industry has acknowledged problems that can be and are being managed. But the industry also has a number of political difficulties that could be beyond its ability to resolve with its own resources. These are issues common to the introduction of new technologies into a complex world. Nevertheless, nuclear power continues to be the means by which we can provide the electric power needed to raise the living standard of everyone on the globe

Current neutralization of converging ion beams

International Nuclear Information System (INIS)

Mosher, D.

1978-01-01

It is desired to consider the problem of current neutralization of heavy ion beams traversing gas backgrounds in which the conductivity changes due to beam heating and beam convergence. The procedure is to determine Green's-function solutions to the magnetic-diffusion equation derived from Maxwell's equations and an assumed scaler-plasma conductivity sigma for the background-electron current density j/sub e/. The present calculation is more general than some previously carried out in that arbitrary time variations for the beam current j/sub b/ and conductivity are allowed and the calculation is valid for both weak and strong neutralization. Results presented here must be combined with an appropriate energy-balance equation for the heated background in order to obtain the neutralization self-consistently

Obtaining of uranium tetrafluoride UF4 by electrodialysis reactive from uranium concentrates

International Nuclear Information System (INIS)

Munoz Lay, Danny Mauricio

2014-01-01

The generation of uranium fuels has always been a topic worldwide. The uranium fuel manufacturing base is made under very strict parameters of radiological and industrial safety, being a stage called 'nuclear fuel cycle'. In Chile, it is done constant research for fuels. This report focuses primarily on participating in such research; mainly in the production of uranium tetrafluoride (UF 4 ) .The tetrafluoride production is very crucial for the nuclear fuel industry. Its production varies from precipitation in stirred conditions to electrolysis in mercury. However, both processes has shortcomings either in performance and environmental pollution, which is why it is proposed a new method of production based on a friendly process to the environment and easier to operate, the reactive electrodialysis (RED). Electrodialysis is a hybrid reactive process of separation by membranes, cationic and / or anionic, namely, ionic species. In the process, ions are induced to move by an electric potential applied and separated by these membranes, a highly selective physical barrier which allows passage of ions with certain charge, and prevents the passage of oppositely charged ions. And in turn, it is reactive because it forces a chemical reaction, redox, to obtain uranium tetrafluoride (UF 4 ). The results of these experiments show that by reactive electrodialysis, NH 4 UF 5 deposits were obtained. However, calcinating the NH 4 UF 5 to 450 o C, it decomposes to obtain uranium tetrafluoride, UF 4 . The best working conditions were obtained with an electric current of 0.5 (A), 41 o C and a flow of 16 (ml / s) of the electrolyte. It was possible to obtain 5,995 (g) to 3 (h), giving a current efficiency of 71.42%. In turn, working at high temperatures and flow recirculation is possible to operate with a potential difference of 1.7 (V)

The Effects of Different Electrode Types for Obtaining Surface Machining Shape on Shape Memory Alloy Using Electrochemical Machining

Science.gov (United States)

Choi, S. G.; Kim, S. H.; Choi, W. K.; Moon, G. C.; Lee, E. S.

2017-06-01

Shape memory alloy (SMA) is important material used for the medicine and aerospace industry due to its characteristics called the shape memory effect, which involves the recovery of deformed alloy to its original state through the application of temperature or stress. Consumers in modern society demand stability in parts. Electrochemical machining is one of the methods for obtained these stabilities in parts requirements. These parts of shape memory alloy require fine patterns in some applications. In order to machine a fine pattern, the electrochemical machining method is suitable. For precision electrochemical machining using different shape electrodes, the current density should be controlled precisely. And electrode shape is required for precise electrochemical machining. It is possible to obtain precise square holes on the SMA if the insulation layer controlled the unnecessary current between electrode and workpiece. If it is adjusting the unnecessary current to obtain the desired shape, it will be a great contribution to the medical industry and the aerospace industry. It is possible to process a desired shape to the shape memory alloy by micro controlling the unnecessary current. In case of the square electrode without insulation layer, it derives inexact square holes due to the unnecessary current. The results using the insulated electrode in only side show precise square holes. The removal rate improved in case of insulated electrode than others because insulation layer concentrate the applied current to the machining zone.

Modeling of Lightning Strokes Using Two-Peaked Channel-Base Currents

Directory of Open Access Journals (Sweden)

V. Javor

2012-01-01

Full Text Available Lightning electromagnetic field is obtained by using “engineering” models of lightning return strokes and new channel-base current functions and the results are presented in this paper. Experimentally measured channel-base currents are approximated not only with functions having two-peaked waveshapes but also with the one-peaked function so as usually used in the literature. These functions are simple to be applied in any “engineering” or electromagnetic model as well. For the three “engineering” models: transmission line model (without the peak current decay, transmission line model with linear decay, and transmission line model with exponential decay with height, the comparison of electric and magnetic field components at different distances from the lightning channel-base is presented in the case of a perfectly conducting ground. Different heights of lightning channels are also considered. These results enable analysis of advantages/shortages of the used return stroke models according to the electromagnetic field features to be achieved, as obtained by measurements.

Square pulse current wave’s effect on electroplated nickel hardness

Directory of Open Access Journals (Sweden)

Bibian Alonso Hoyos

2006-09-01

Full Text Available The effects of frequency, average current density and duty cycle on the hardness of electroplated nickel were studied in Watts and sulphamate solutions by means of direct and square pulse current. The results in Watts’ solutions revealed greater hardness at low duty cycle, high average current density and high square pulse current frequency. There was little variation in hardness in nickel sulphamate solutions to changes in duty cycle and wave frequency. Hardness values obtained in the Watts’ bath with square pulse current were higher than those achieved with direct current at the same average current density; such difference was not significant in sulphamate bath treatment.

Theory of potentiostatic current transients for coupled catalytic reaction at random corrugated fractal electrode

International Nuclear Information System (INIS)

Jha, Shailendra K.; Kant, Rama

2010-01-01

We developed a mathematical model for the first order homogeneous catalytic chemical reaction coupled with an electron transfer (EC') on a rough working electrode. Results are obtained for the various roughness models of electrode corrugations, viz., (i) roughness as an exact periodic function, (ii) roughness as a random function with known statistical properties, and (iii) roughness as a random function with statistical self-affine fractality over a finite range of length scales. Method of Green's function is used in the formulation to obtain second-order perturbation (in roughness profile) expressions for the concentration, the local current density and the current transients. A general operator structure between these quantities and arbitrary roughness profile is emphasized. The statistically averaged (randomly rough) electrode response is obtained by an ensemble averaging over all possible surface configurations. An elegant mathematical formula between the average electrochemical current transient and surface structure factor or power-spectrum of roughness is obtained. This formula is used to obtain an explicit equation for the current on an approximately self-affine (or realistic) fractal electrode with a limited range of length scales of irregularities. This description of realistic fractal is obtained by cutoff power law power-spectrum of roughness. The realistic fractal power-spectrum consists of four physical characteristics, viz., the fractal dimension (D H ), lower (l) and upper (L) cutoff length scales of fractality and a proportionality factor (μ), which is related to the topothesy or strength of fractality. Numerical calculations are performed on final results to understand the effect of catalytic reaction and fractal morphological characteristics on potentiostatic current transients.

Standardization of a fluconazole bioassay and correlation of results with those obtained by high-pressure liquid chromatography.

Science.gov (United States)

Rex, J H; Hanson, L H; Amantea, M A; Stevens, D A; Bennett, J E

1991-01-01

An improved bioassay for fluconazole was developed. This assay is sensitive in the clinically relevant range (2 to 40 micrograms/ml) and analyzes plasma, serum, and cerebrospinal fluid specimens; bioassay results correlate with results obtained by high-pressure liquid chromatography (HPLC). Bioassay and HPLC analyses of spiked plasma, serum, and cerebrospinal fluid samples (run as unknowns) gave good agreement with expected values. Analysis of specimens from patients gave equivalent results by both HPLC and bioassay. HPLC had a lower within-run coefficient of variation (less than 2.5% for HPLC versus less than 11% for bioassay) and a lower between-run coefficient of variation (less than 5% versus less than 12% for bioassay) and was more sensitive (lower limit of detection, 0.1 micrograms/ml [versus 2 micrograms/ml for bioassay]). The bioassay is, however, sufficiently accurate and sensitive for clinical specimens, and its relative simplicity, low sample volume requirement, and low equipment cost should make it the technique of choice for analysis of routine clinical specimens. PMID:1854166

Edaphic macrofauna as biological indicator of the conservation/disturbance status of soil. Results obtained in Cuba

International Nuclear Information System (INIS)

Cabrera, Grisel

2012-01-01

In order to predict the degradation status of a soil, a group of variables comprising its physical, chemical and/or biological properties is used. Macrofauna, which includes soil invertebrates higher than 2 mm of diameter, is a biological component that can be used for such purpose. Its taxonomic richness as well as its density, biomass and functional composition change depending on the effect of diverse land uses and managements. This review reaffirms that the macrofauna characteristics and the results obtained, mainly in Cuba, about its variation in ecosystems with different anthropization levels, support the potential use of this fauna as biological indicator of the soil's conservation status. Future studies should consider a lower taxonomic level in the identification of macrofauna, and relate its taxonomic and functional composition to the climate and pedological factors. (author)

Self-consistent model for pulsed direct-current N2 glow discharge

International Nuclear Information System (INIS)

Liu Chengsen

2005-01-01

A self-consistent analysis of a pulsed direct-current (DC) N 2 glow discharge is presented. The model is based on a numerical solution of the continuity equations for electron and ions coupled with Poisson's equation. The spatial-temporal variations of ionic and electronic densities and electric field are obtained. The electric field structure exhibits all the characteristic regions of a typical glow discharge (the cathode fall, the negative glow, and the positive column). Current-voltage characteristics of the discharge can be obtained from the model. The calculated current-voltage results using a constant secondary electron emission coefficient for the gas pressure 133.32 Pa are in reasonable agreement with experiment. (authors)

Overview of the FTU results

International Nuclear Information System (INIS)

Alladio, F.; Angelini, B.; Apicella, M.L.

1999-01-01

An overview of the Frascati Tokamak Upgrade results during the period 1996-1998 is presented. Most of the activity has been devoted to the investigation of the electron heat transport with flat/nonmonotonic safety factor profiles. Up to 14 keV of electron temperature have been obtained using electron cyclotron resonance heating (ECRH) on the current ramp. The transport analysis shows a very low electron heat transport in the region with flat/nonmonotonic safety factor profile. The electron thermal conductivity is strongly dependent on the MHD activity and it drops to values of the order 0.1 m 2 /s in the absence of MHD fluctuations. Upon varying the resonance position in steady state conditions the effect of the ECRH on the sawtooth stabilization has been also investigated. Lower hybrid current drive studies have been performed in order to investigate the dependence of the current drive efficiency with density. Previous results of the Alcator C tokamak pointed out that at high density rather low efficiency values were obtained. The investigation carried out on FTU shows that such a result can be explained as due to the electron temperature dependence of the current drive efficiency. No degradation of the current drive efficiency is indeed observed on FTU even at density values of the order 10 20 m -3 . Ion Bernstein wave (IBW) heating studies have been also carried out in order to check the behaviour of wave-plasma coupling which is found in agreement with linear theory. Finally, impurity transport studies have been carried out. It has been possible to have a direct measurement of the flux of Mo33 which turns out to be in agreement with the expectation of quasilinear theory. (author)

Results of the new eddy current tester for steam generator applications

International Nuclear Information System (INIS)

Ribes, B.; Hernandez, J.; Barcenilla, V.

2006-01-01

As a result of the recent developing line of eddy current data acquisition systems a new product comes to the market named Teddy+. With only 4 kg of weight constitutes a great advance with regards to the equipments used for this type of inspections available in the market. This advances, have enabled, among others, to increase considerably the S/N ratio, avoid typical saturation problems in the eddy current signal, increase the inspection speed, eliminate the reference probe, detect the air/tube signal in real time, together with the possibility to integrate the tester inside the pusher thanks to its reduced size and to have integrated the mechanical systems control board as part of the tester. The software application in charge of data acquisition and analysis has been optimized making it possible a faster and efficient data access, incorporating a new tool to allow a data quality control on-line, which has accelerated the detection process of non-valid registers. The processes related with the supervision of different analysis have been automated enabling a simultaneous comparison of up to four different analysis types. At the same time the necessary tools to make the successive passes of the resolution process have been included in the analysis software according to EPRI guidelines. These innovations and improvements place the new SG inspection system from TECNATOM, as one of the most powerful and reliable existing in the market (orig.)

Influence of current and temperature on discharge characteristics of electrochemical nickel−cadmium system

Directory of Open Access Journals (Sweden)

Todorović Andreja

2010-01-01

Full Text Available The paper elaborates determination of characteristic values in the discharging process of non-hermetic nickel-cadmium galvanic battery with nominal voltage Un = 60 V and nominal capacity qn = C5 = 190 Ah and its dependence from current and temperature. Study has been performed with the set of experimental metering of voltages, electromotive force, current from discharge time range and electromotive force in steady state regime before and after battery charging. Electromotive force characteristics are obtained by using the Nernst’s equation, while the least square method was used to determine the average values of internal electrical resistivity, power losses and efficiency level. These results were used in the approximate exponential functions to determine the range dependence of the efficiency level from the internal electrical resistance of discharge current in reliance from the temperature range. Obtained results show that, in accordance to the given voltage variation of 10% Un, this type of battery holds maximal full load current of one hour capacity at the temperature of 25°C and maximal full load current of two hours capacity at the temperature of −30°C. The methodology used in the case study covers determination of the electromotive force in time range based on the metered results of values during complete battery fullness and emptiness with prior determination of equilibrium constants of galvanic battery reaction through method suggested by the author of this paper. Further process, using the electromotive force values obtained through the aforementioned process, the metered current, and approximate polynomial function of the nominal discharge voltage characteristic determines range of battery internal electric resistance from time, followed by the selection of discharge cases with average values for: voltage, electromotive force, internal electrical resistance, available and utilized power, power losses, and battery efficiency

Eddy current inspection of tubing; Inspeccion de tubos por corrientes de Foucault

Energy Technology Data Exchange (ETDEWEB)

Bauza, J L. R.; Herrero, J; Diaz, J

1966-07-01

The Experimental research work carried out to develop a Eddy current testing equipment is described. Search coils with ferrite or air cores were used and the obtained results are discussed. Valuable information was gained from a improved channel in which a direct measure of the defect and the reference signal phase difference is obtained. Artificial defect used to evaluate resolution and sensitivity were produced by electro-machining and mechanical means. Finned SAP tubing was tested in a routine basis with the described equipment and the results plotted. Basic and theoretical considerations on the Eddy current testing technique are given in the last section of this report. (Author)

Effect of eddy current damping on phononic band gaps generated by locally resonant periodic structures

Science.gov (United States)

Ozkaya, Efe; Yilmaz, Cetin

2017-02-01

The effect of eddy current damping on a novel locally resonant periodic structure is investigated. The frequency response characteristics are obtained by using a lumped parameter and a finite element model. In order to obtain wide band gaps at low frequencies, the periodic structure is optimized according to certain constraints, such as mass distribution in the unit cell, lower limit of the band gap, stiffness between the components in the unit cell, the size of magnets used for eddy current damping, and the number of unit cells in the periodic structure. Then, the locally resonant periodic structure with eddy current damping is manufactured and its experimental frequency response is obtained. The frequency response results obtained analytically, numerically and experimentally match quite well. The inclusion of eddy current damping to the periodic structure decreases amplitudes of resonance peaks without disturbing stop band width.

Current matrix element in HAL QCD's wavefunction-equivalent potential method

Science.gov (United States)

Watanabe, Kai; Ishii, Noriyoshi

2018-04-01

We give a formula to calculate a matrix element of a conserved current in the effective quantum mechanics defined by the wavefunction-equivalent potentials proposed by the HAL QCD collaboration. As a first step, a non-relativistic field theory with two-channel coupling is considered as the original theory, with which a wavefunction-equivalent HAL QCD potential is obtained in a closed analytic form. The external field method is used to derive the formula by demanding that the result should agree with the original theory. With this formula, the matrix element is obtained by sandwiching the effective current operator between the left and right eigenfunctions of the effective Hamiltonian associated with the HAL QCD potential. In addition to the naive one-body current, the effective current operator contains an additional two-body term emerging from the degrees of freedom which has been integrated out.

Results obtained by Trillo Nuclear Power Plant in 2001

International Nuclear Information System (INIS)

Solar, V.

2002-01-01

Unification of the Almaraz and Trillo plant managements was given a strong boost with unification of the central offices and management computer platforms (economic and technical) and with signature of an agreement with Madrid's trade unions providing for appropriate management of surpluses and the transfer of knowledge between people leaving the company and those taking their place. The operating results have been maintained at a high level although they were lower than last year, which was exceptional. The plant was on line for 7,979 hours, most of them at full load. (Author)

Noninductive current drive for INTOR: A comparison of four driver options

International Nuclear Information System (INIS)

Ehst, D.A.; Evans, K. Jr.; Mikkelsen, D.R.; Ignat, D.W.; Mau, T.K.

1987-01-01

The current drive power and normalized efficiency are calculated for the INTOR tokamak, including spatial profiles of the plasma and current density. Current drive requirements are computed for purely steady state operation with no electromotive force and also in the presence of a reversed emf typical of start-up or transformer recharging. Results are obtained for lower-hybrid-waves, high frequency fast waves, low frequency fast waves and neutral beam injection

High-temperature performance of MoS{sub 2} thin-film transistors: Direct current and pulse current-voltage characteristics

Energy Technology Data Exchange (ETDEWEB)

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.

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

International Nuclear Information System (INIS)

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

Eddy current testing

Energy Technology Data Exchange (ETDEWEB)

Song, Sung Jin; Lee, Hyang Beom; Kim, Young Hwan [Soongsil Univ., Seoul (Korea, Republic of); Shin, Young Kil [Kunsan Univ., Gunsan (Korea, Republic of)

2004-02-15

Eddy current testing has been widely used for non destructive testing of steam generator tubes. In order to retain reliability in ECT, the following subjects were carried out in this study: numerical modeling and analysis of defects by using BC and RPC probes in SG tube, preparation of absolute coil impedance plane diagram by FEM. Signal interpretation of the eddy current signals obtained from nuclear power plants.

Eddy current testing

International Nuclear Information System (INIS)

Song, Sung Jin; Lee, Hyang Beom; Kim, Young Hwan; Shin, Young Kil

2004-02-01

Eddy current testing has been widely used for non destructive testing of steam generator tubes. In order to retain reliability in ECT, the following subjects were carried out in this study: numerical modeling and analysis of defects by using BC and RPC probes in SG tube, preparation of absolute coil impedance plane diagram by FEM. Signal interpretation of the eddy current signals obtained from nuclear power plants

Simple WZW currents

International Nuclear Information System (INIS)

Fuchs, J.

1990-08-01

A complete classification of simple currents of WZW theory is obtained. The proof is based on an analysis of the quantum dimensions of the primary fields. Simple currents are precisely the primaries with unit quantum dimension; for WZW theories explicit formulae for the quantum dimensions can be derived so that an identification of the fields with unit quantum dimension is possible. (author). 19 refs.; 2 tabs

Report of test and research results on atomic energy obtained in national institutes in fiscal 1985

International Nuclear Information System (INIS)

1986-01-01

As for the test and research on the utilization of atomic energy in national institutes, the budget was appropriated for the first time in fiscal year 1956, and since then, the many valuable results of research have been obtained so far in the diversified fields of nuclear fusion, safety research, the irradiation of foods, medicine and others, thus the test and research accomplished the large role for promoting the utilization of atomic energy in Japan. In this report, the gists of the results of the test and research on the utilization of atomic energy carried out by national institutes in fiscal year 1985 are collected. No.1 of this report was published in 1960, and this is No.26. It is desired to increase the understanding about the recent trend and the results of the test and research on atomic energy utilization with this book. The researches on nuclear fusion, engineering safety and environmental radioactivity safety, the irradiation of foods, the countermeasures against cancer, fertilized soil, the quality improvement of brewing and farm products, the protection of farm products and the improvement of breeding, diagnosis and medical treatment, pharmaceuticals, environmental hygiene, the application to physiology and pathology, radiochemistry, radiation measurement, process analysis, nuclear reactor materials, nuclear powered ships, civil engineering, radioactivation analysis and injury prevention are reported. (Kako, I.)

Classification of simple current invariants

CERN Document Server

Gato-Rivera, Beatriz

1992-01-01

We summarize recent work on the classification of modular invariant partition functions that can be obtained with simple currents in theories with a center (Z_p)^k with p prime. New empirical results for other centers are also presented. Our observation that the total number of invariants is monodromy-independent for (Z_p)^k appears to be true in general as well. (Talk presented in the parallel session on string theory of the Lepton-Photon/EPS Conference, Geneva, 1991.)

Current pulse shaping of the load current on PTS

Directory of Open Access Journals (Sweden)

Minghe Xia

2016-02-01

Full Text Available The typical rise time of PTS machine is ∼110 ns with about 10 MA peak current under short pulse mode when all 24 modules discharge simultaneously. By distributing the trigger times of 12 laser beams logically and adjusting the statues of the pulse output switches, longer rise-time pulse can be obtained on the PTS facility. Based on the required pulse shape, whole circuit simulations will be used to calculate the trigger times of each laser triggering gas switch and the status of the pulse output switches. The rise time of the current is determined by the time difference between the first and last trigged laser triggering gas switches. In order to trigger the laser triggering gas switch, sufficient laser power is needed to be sent into the gap of the gas switches. The gas pressure and voltage difference on the two electrodes of the gas switches also affect the triggering of the gas switches, and the voltage added on the gas switch is determined by its transition time. Traditionally the trigger time difference should be less than the transition time of the two neighboring modules. A new simulation model of PTS shows one can break this transition time limits. Series of current pulse shaping experiments have been investigated on the PTS (Primary Test Stand. As results, more than 5 MA peak current were successfully achieved on the load with a rise time of 600 ns. This study and experiments of the pulse shaping on PTS demonstrate the adaptable ability of the PTS for offering different waveform of mega ampere current pulse for different research purpose.

Mesoporous silicon oxide films and their uses as templates in obtaining nanostructured conductive polymers

Science.gov (United States)

Salgado, R.; Arteaga, G. C.; Arias, J. M.

2018-04-01

Obtaining conductive polymers (CPs) for the manufacture of OLEDs, solar cells, electrochromic devices, sensors, etc., has been possible through the use of electrochemical techniques that allow obtaining films of controlled thickness with positive results in different applications. Current trends point towards the manufacture of nanomaterials, and therefore it is necessary to develop methods that allow obtaining CPs with nanostructured morphology. This is possible by using a porous template to allow the growth of the polymeric materials. However, prior and subsequent treatments are required to separate the material from the template so that it can be evaluated in the applications mentioned above. This is why mesoporous silicon oxide films (template) are essential for the synthesis of nanostructured polymers since both the template and the polymer are obtained on the electrode surface, and therefore it is not necessary to separate the material from the template. Thus, the material can be evaluated directly in the applications mentioned above. The dimensions of the resulting nanostructures will depend on the power, time and technique used for electropolymerization as well as the monomer and the surfactant of the mesoporous film.

Micromagnetic Simulation of Strain-Assisted Current-Induced Magnetization Switching

Directory of Open Access Journals (Sweden)

H. B. Huang

2016-01-01

Full Text Available We investigated the effect of substrate misfit strain on the current-induced magnetization switching in magnetic tunnel junctions by combining micromagnetic simulation with phase-field microelasticity theory. Our results indicate that the positive substrate misfit strain can decrease the critical current density of magnetization switching by pushing the magnetization from out-of-plane to in-plane directions, while the negative strain pushes the magnetization back to the out-of-plane directions. The magnetic domain evolution is obtained to demonstrate the strain-assisted current-induced magnetization switching.

Results obtained during wall breaching research

CSIR Research Space (South Africa)

Hattingh, S

2008-11-01

Full Text Available To understand the physics of what is happening inside the wall directly after the detonation and the application of this knowledge in the improvement of the charge Measure the shock/stress waves in the masonry material and then in the wall as a whole... to maximise the effect of the charges on the walls and to broaden the knowledge of the physics of shock and stress waves. The thickness and characteristics of walls are not usually known in an operation. The effect of the charges on real buildings is still...

Evaluation of magnetic properties of NI-ZN ferrites obtained by different synthesis methods

International Nuclear Information System (INIS)

Simoes, A.N.; Neiva, L.S.; Simoes, V.N.; Gama, L.; Gomes Filho, A.C.; Oliveira, J.B.L.

2012-01-01

Ceramic oxides that exhibit ferromagnetic behavior represent important commercial products for the electronics industry and are commonly known as ferrites. The Ni-Zn ferrites are considered to be one of the most versatile and soft due to its high electrical resistivity and low eddy current losses. Thus, this study aims to evaluate the magnetic properties of Ni-Zn ferrite obtained by the Pechini and combustion reaction. After synthesis the powders were characterized by XRD, SEM, BET and magnetic measurements. The results showed that for both methods of synthesis used was the formation of the spinel phase of Ni-Zn ferrite. The micrographs show that the powders obtained by both methods have regular shapes and spherical. Were determined by BET surface area is 26 m 2 /g by the Pechini and 13 m 2 /g by combustion. And the samples synthesized by Pechini method obtained the best magnetic characteristics (author)

Analysis of current diffusive ballooning mode

International Nuclear Information System (INIS)

Yagi, M.; Azumi, M.; Itoh, K.; Itoh, S.; Fukuyama, A.

1993-04-01

The current diffusive ballooning mode is analysed in the tokamak plasma. This mode is destabilized by the current diffusivity (i.e., the electron viscosity) and stabilized by the thermal conductivity and ion viscosity. By use of the ballooning transformation, the eigenmode equation is solved. Analytic solution is obtained by the strong ballooning limit. Numerical calculation is also performed to confirm the analytic theory. The growth rate of the mode and the mode structure are analysed. The stability boundary is derived in terms of the current diffusivity, thermal conductivity, ion viscosity and the pressure gradient for the given shear parameter. This result is applied to express the thermal conductivity in terms of the pressure gradient, magnetic configurational parameters (such as the safety factor, shear and aspect ratio) and the Prandtl numbers. (author)

Analytical Model of Subthreshold Drain Current Characteristics of Ballistic Silicon Nanowire Transistors

Directory of Open Access Journals (Sweden)

Wanjie Xu

2015-01-01

Full Text Available A physically based subthreshold current model for silicon nanowire transistors working in the ballistic regime is developed. Based on the electric potential distribution obtained from a 2D Poisson equation and by performing some perturbation approximations for subband energy levels, an analytical model for the subthreshold drain current is obtained. The model is further used for predicting the subthreshold slopes and threshold voltages of the transistors. Our results agree well with TCAD simulation with different geometries and under different biasing conditions.

Thermally induced spin-dependent current based on Zigzag Germanene Nanoribbons

Science.gov (United States)

Majidi, Danial; Faez, Rahim

2017-02-01

In this paper, using first principle calculation and non-equilibrium Green's function, the thermally induced spin current in Hydrogen terminated Zigzag-edge Germanene Nanoribbon (ZGeNR-H) is investigated. In this model, because of the difference between the source and the drain temperature of ZGeNR device, the spin up and spin down currents flow in the opposite direction with two different threshold temperatures (Tth). Hence, a pure spin polarized current which belongs to spin down is obtained. It is shown that, for temperatures above the threshold temperature spin down current increases with the increasing temperature up to 75 K and then decreases. But spin up current rises steadily and in the high temperature we can obtain polarized spin up current. In addition, we show an acceptable spin current around the room temperature for ZGeNR. The transmission peaks in ZGeNR which are closer to the Fermi level rather than Zigzag Graphene Nanoribbon (ZGNRS) which causes ZGeNR to have spin current at higher temperatures. Finally, it is indicated that by tuning the back gate voltage, the spin current can be completely modulated and polarized. Simulation results verify the Zigzag Germanene Nanoribbon as a promising candidate for spin caloritronics devices, which can be applied in future low power consumption technology.

Aircraft and ground vehicle friction correlation test results obtained under winter runway conditions during joint FAA/NASA Runway Friction Program

Science.gov (United States)

Yager, Thomas J.; Vogler, William A.; Baldasare, Paul

1988-01-01

Aircraft and ground vehicle friction data collected during the Joint FAA/NASA Runway Friction Program under winter runway conditions are discussed and test results are summarized. The relationship between the different ground vehicle friction measurements obtained on compacted snow- and ice-covered conditions is defined together with the correlation to aircraft tire friction performance under similar runway conditions.

Oxidation of organic pollutants on BDD anodes using modulated current electrolysis

International Nuclear Information System (INIS)

Panizza, M.; Kapalka, Agnieszka; Comninellis, Ch.

2008-01-01

In this paper, a theoretical model is presented for organic pollutants mineralization at high current efficiency (close to 100%) and low energy consumption on boron-doped diamond electrodes. The model is formulated for a perfect mixed electrochemical reactor operated as a batch recirculation system under multiple current steps, in which the applied current is adjusted during the electrolysis to be close to the limiting value. An experimental validation with the anodic oxidation of 3,4,5-trihydroxybenzoic acid is also provided. The results have shown that multiple current steps electrolysis and continuous current control allowed obtaining high oxidation rate and current efficiency

Oxidation of organic pollutants on BDD anodes using modulated current electrolysis

Energy Technology Data Exchange (ETDEWEB)

Panizza, M. [Department of Chemical and Process Engineering, University of Genoa, P.le J.F. Kennedy 1, 16129 Genova (Italy)], E-mail: marco.panizza@unige.it; Kapalka, Agnieszka [Institute of Chemical Sciences and Engineering, Ecole Polytechnique Federale de Lausanne (EPFL), CH-1015 Lausanne (Switzerland); Comninellis, Ch. [Institute of Chemical Sciences and Engineering, Ecole Polytechnique Federale de Lausanne (EPFL), CH-1015 Lausanne (Switzerland)], E-mail: christos.comninellis@epfl.ch

2008-01-01

In this paper, a theoretical model is presented for organic pollutants mineralization at high current efficiency (close to 100%) and low energy consumption on boron-doped diamond electrodes. The model is formulated for a perfect mixed electrochemical reactor operated as a batch recirculation system under multiple current steps, in which the applied current is adjusted during the electrolysis to be close to the limiting value. An experimental validation with the anodic oxidation of 3,4,5-trihydroxybenzoic acid is also provided. The results have shown that multiple current steps electrolysis and continuous current control allowed obtaining high oxidation rate and current efficiency.

Results Obtained in Training Romanian Sport Horses for Jumping Competitions

Directory of Open Access Journals (Sweden)

Flavia Luminiţa Bochiş

2012-10-01

Full Text Available A number of 29 equines, Romanian Sport Horse stallions, were taken as green horses, break into the saddle, andteach into basic training while later train as jumpers over three years. The obstacle courses results had been obtainedin our country, in Hungary and in Serbia. There were courses jumped in the national championship, somedemonstrations organized in Romania or in the two foreign countries, or periodically test pattern courses run on theown arena. The best results, respectively more than 50% obstacle courses with no fault points over 3 years, were runby five stallions, and the same percent for 2 seasons, was reached by nine stallions.

Photonic chiral current and its anomaly in a gravitational field

International Nuclear Information System (INIS)

Dolgov, A.D.; Khriplovich, I.B.; Vajnshtejn, A.I.; Zakharov, V.I.

1988-01-01

The notion of chirality for electromagnetic field which is conserved in interactions with gravitons is formulated. The correponding chiral current is the one-particle-state analogue of the Pauli-Lubansky vector. The anomaly of this current in an external gravitational field is found. The results obtained are used for the calculation of the electromagnetic radiative correction to the fermionic chiral anomaly in a gravitational field

Current drive by asymmetrical heating in a toroidal plasma

International Nuclear Information System (INIS)

Gahl, J.M.

1986-01-01

This report describes the first experimental observation of current generation by asymmetrical heating of ions. A unidirectional fast Alfven wave launched by a slow-wave antenna inside the Texas Tech Tokamak, asymmetrically heated the ions. Measurements of the asymmetry of the toroidal plasma current with probes at the top and bottom of the toroidal plasma column confirmed the current generation indirectly. Current generation, obtained in a one-species, hydrogen plasma, is a phenomenon which had not been predicted previously. Calculations of the dispersion relation for the fast Alfven wave near the fundamental cyclotron resonance in a one-species, hydrogen plasma, using warm plasma theory, support the experimental results

Are there missing convective currents?

International Nuclear Information System (INIS)

Chen, C.Y.

1992-01-01

It is revealed in this letter that as far as distribution functions obtained from gyrokinetic equations are concerned, the standard formulae to evaluate currents in plasmas are not applicable due to the fact that those distribution functions are given in a moving coordinate frame and the moving is essentially related to perturbed fields. With heuristic and analytic approaches, appropriate formulae are obtained to evaluate several types of currents in plasmas of which some have been missing in previous approaches. (author). 6 refs, 1 fig

Influence of sintering parameters in the ferroelectric properties os strontium bismuth tantalate samples obtained by oxide mixture

International Nuclear Information System (INIS)

Souza, R.R. de; Pereira, A.S.; Sousa, V.C.; Egea, J.R.J.

2012-01-01

The family of compounds layered-type perovskite, know as Aurivilius presents great alternative not only by the absence of lead in the composition, but because the polarization retention, replacing PZT in FeRAM devices. The strontium bismuth tantalate (SrBi 2 Ta 2 O 9 ) or SBT is ferroelectric material that has attracted considerable interest, since it has high fatigue resistance, supporting high hysteresis loops, with the change in polarization.Checking polarization and depolarization currents stimulated by temperature it is possible to obtain, for example, information about the nature of charges and about the activation energy for the process of dielectric relaxation. For analysis of ferroelectric properties of this compound, it is essential to obtain specimens with a relative density around 95%. Thus, it is important the optimization of the sintering process in order to obtain a ceramic body with a high densification. The influence of sintering parameters to obtain SrBi 2 Ta 2 O 9 in the polarization properties and in the microstructure of sintered samples was investigated by thermostimulated currents and electronic microscopy, respectively. Results show that variation of these parameters may cause changes in the ferroelectric properties of the material. (author)

Variable current speed controller for eddy current motors

Science.gov (United States)

Gerth, H.L.; Bailey, J.M.; Casstevens, J.M.; Dixon, J.H.; Griffith, B.O.; Igou, R.E.

1982-03-12

A speed control system for eddy current motors is provided in which the current to the motor from a constant frequency power source is varied by comparing the actual motor speed signal with a setpoint speed signal to control the motor speed according to the selected setpoint speed. A three-phase variable voltage autotransformer is provided for controlling the voltage from a three-phase power supply. A corresponding plurality of current control resistors is provided in series with each phase of the autotransformer output connected to inputs of a three-phase motor. Each resistor is connected in parallel with a set of normally closed contacts of plurality of relays which are operated by control logic. A logic circuit compares the selected speed with the actual motor speed obtained from a digital tachometer monitoring the motor spindle speed and operated the relays to add or substract resistance equally in each phase of the motor input to vary the motor current to control the motor at the selected speed.

Use of an Ultrasonic/Sonic Driller/Corer to Obtain Sample Powder for CHEMIN, a Combined XRD/XRF Instrument

Science.gov (United States)

Chipera, S. J.; Bish, D. L.; Vaniman, D. T.; Sherrit, S.; Bar-Cohen, Y.; Sarrazin, P.; Blake, D. F.

2003-01-01

A miniature CHEMIN XRD/XRF (X-Ray Diffraction/X-Ray Fluourescence) instrument is currently being developed for definitive mineralogic analysis of soils and rocks on Mars. One of the technical issues that must be addressed in order to enable XRD analysis on an extraterrestrial body is how best to obtain a representative sample powder for analysis. For XRD powder diffraction analyses, it is beneficial to have a fine-grained sample to reduce preferred orientation effects and to provide a statistically significant number of crystallites to the X-ray beam. Although a 2-dimensional detector as used in the CHEMIN instrument will produce good results with poorly prepared powders, the quality of the data will improve if the sample is fine-grained and randomly oriented. An Ultrasonic/Sonic Driller/Corer (USDC) currently being developed at JPL is an effective mechanism of sampling rock to produce cores and powdered cuttings. It requires low axial load (XRD/XRF spectrometer such as CHEMIN, powders obtained from the JPL ultrasonic drill were analyzed and the results were compared to carefully prepared powders obtained using a laboratory bench scale Retsch mill.

On-line monitoring of base current and forward emitter current gain of the voltage regulator's serial pnp transistor in a radiation environment

Directory of Open Access Journals (Sweden)

Vukić Vladimir Đ.

2012-01-01

Full Text Available A method of on-line monitoring of the low-dropout voltage regulator's operation in a radiation environment is developed in this paper. The method had to enable detection of the circuit's degradation during exploitation, without terminating its operation in an ionizing radiation field. Moreover, it had to enable automatic measurement and data collection, as well as the detection of any considerable degradation, well before the monitored voltage regulator's malfunction. The principal parameters of the voltage regulator's operation that were monitored were the serial pnp transistor's base current and the forward emitter current gain. These parameters were procured indirectly, from the data on the voltage regulator's load and quiescent currents. Since the internal consumption current in moderately and heavily loaded devices was used, the quiescent current of a negligibly loaded voltage regulator of the same type served as a reference. Results acquired by on-line monitoring demonstrated marked agreement with the results acquired from examinations of the voltage regulator's maximum output current and minimum dropout voltage in a radiation environment. The results were particularly consistent in tests with heavily loaded devices. Results obtained for moderately loaded voltage regulators and the risks accompanying the application of the presented method, were also analyzed.

Preliminary results of proton ring current observations in time of magnetic perturbations with the 'Molniya-1' satellite

International Nuclear Information System (INIS)

Grechin, A.N.; Kovrygina, L.M.; Kovtyukh, A.S.

1975-01-01

The experimental results of observation on the injection of the annular current protons (30< Esub(r)<380 KeV) into the radiation band during the storm on October 28, 1973 and three storms on January 1, 1974, July 12 and 21, 1974, with the maximum values of Dsup(st) of 65, 30, and 20γ, respectively, are described. During the main phases of the storms the assymetry of the annular current of protons relative to the mid-day-mid-night meridian was observed. The injection of the particles was being accompanied by variation of the shape of the spectrum on the internal edge of the annular current. The possible effect of the ion-cyclotron instability on the formation of the initial edge of the annular current has been analyzed. Immediately after the main phases of the storms on July 12 and 21, 1974, a gap in the spectum within the pre-mid-night sector, with the energies amounting to several dozens of KeV was observed. The formation of this gap may be explained by the development of the instability which results in the pinch-angular diffusion of protons and their decay in the region of plasmapause

Comparison of Vespula germanica venoms obtained from different sources.

Science.gov (United States)

Sanchez, F; Blanca, M; Miranda, A; Carmona, M J; Garcia, J; Fernandez, J; Torres, M J; Rondon, M C; Juarez, C

1994-08-01

This study was carried out to compare the allergenic potency of Vespula germanica (VG) venoms extracted by different methods and commercially available venoms from Vespula species currently used for in vivo and in vitro studies including immunotherapy. Pure VG venom was used as the reference material. Protein content and enzymatic and allergenic properties of all venoms studied were determined by dye stain reagent, hyaluronidase and phospholipase A1B enzyme activities, and radioallergosorbent test inhibition studies, respectively. Radioallergosorbent test discs sensitized with commercial and pure VG venom were compared using specific IgE antibodies from subjects allergic to VG venom. The data obtained indicate that there were important differences in the allergenic potency between the Vespula species venoms employed for in vivo and/or in vitro assays, VG venom obtained by sac dissection, and pure VG venom. These results indicate that venoms from Vespula species used for in vitro and in vivo tests have a lower concentration of allergens and contain nonvenom proteins. These data should be taken into account when these vespid venoms are used for diagnostic purposes and also when evaluating immunotherapy studies.

Macrophytes in the lower Ebro and exploitation of Asco NPP. Current situation

International Nuclear Information System (INIS)

Munte Clua, L.; Esparza Martin, J. L.

2012-01-01

The objective of this stage is to expose the information obtained during the last decade and to present the current situation of the river, the implications involved for the operation of the plant, the solutions adopted in the short term and the results obtained so as proposals that the Administration must respond.

On resonance phenomena in a stellarator with longitudinal current in a plasma

International Nuclear Information System (INIS)

Aleksin, V.F.; Pyatov, V.N.; Sebko, V.P.; Tyupa, V.I.

1976-01-01

A magnetic configuration structure of a stellarator with a current plasma has been considered in the presence of small disturbances. Structures of magnetic fields of a real stellarator configuration with a longitudinal current in a plasma have been obtained by means of averaged coordinates with the subsequent transition to real coordinates. The development of a socket structure and destruction of an integral configuration with an increase of the disturbance amplitude are demonstrated, its range of variation is within the limits of 0.1+-0.01%. Deformations of sockets in different cross sections of the magnetic system along the toroidal axis have been investigated. The results of calculations agree with experimental data obtained at stellarators with a current plasma

Birkeland currents in an anisotropic, magnetostatic plasma

International Nuclear Information System (INIS)

Birmingham, T.J.

1992-01-01

An expression for the parallel current density is derived for a plasma characterized by negligible bulk flow (magnetostatic) velocity and a two-component (anisotropic) pressure tensor by expanding the equilibrium Vlasov equation for each species in the adiabatic parameter until such point as a nonvanishing moment j parallel = ∫ d 3 vv parallel is identified. The result is a nonlocal one: it relates j parallel at one point s along a field line to j parallel at another (reference) point s 0 plus an integral function of the pressure and magnetic field between them. It is a generalization and elaboration of results obtained by Bostrom (1975), Heinemann (1990), and Heinemann and Pontius (1991). The expression could have been obtained by integrating the current continuity equation with -∇ x j perpendicular as a source term and j perpendicular given by perpendicular momentum balance. The authors explicitly show the equivalency. The widely used Vasyliunas (1970) equation follows when P perpendicular is set equal to P parallel and s and s 0 are taken to be at the ionosphere and the equator. An extended discussion of the relationship of results derived here to others in the literature is carried out in an effort to bring unity and perspective to this problem area

Photoinduced currents in pristine and ion irradiated kapton-H polyimide

Science.gov (United States)

Sharma, Anu; Sridharbabu, Y.; Quamara, J. K.

2014-10-01

The photoinduced currents in pristine and ion irradiated kapton-H polyimide have been investigated for different applied electric fields at 200°C. Particularly the effect of illumination intensity on the maximum current obtained as a result of photoinduced polarization has been studied. Samples were irradiated by using PELLETRON facility, IUAC, New Delhi. The photo-carrier charge generation depends directly on intensity of illumination. The samples irradiated at higher fluence show a decrease in the peak current with intensity of illumination. The secondary radiation induced crystallinity (SRIC) is responsible for the increase in maximum photoinduced currents generated with intensity of illumination.

Photoinduced currents in pristine and ion irradiated kapton-H polyimide

Energy Technology Data Exchange (ETDEWEB)

Sharma, Anu, E-mail: sharmaanu81@gmail.com; Sridharbabu, Y., E-mail: sharmaanu81@gmail.com; Quamara, J. K., E-mail: sharmaanu81@gmail.com [Physics Department, SGTB Khalsa college, Delhi University, Delhi (India); Department of Physics, National Institute of Technology, Kurukshetra-136119 (India); Echelon Group of Institutions, Faridabad (India)

2014-10-15

The photoinduced currents in pristine and ion irradiated kapton-H polyimide have been investigated for different applied electric fields at 200°C. Particularly the effect of illumination intensity on the maximum current obtained as a result of photoinduced polarization has been studied. Samples were irradiated by using PELLETRON facility, IUAC, New Delhi. The photo-carrier charge generation depends directly on intensity of illumination. The samples irradiated at higher fluence show a decrease in the peak current with intensity of illumination. The secondary radiation induced crystallinity (SRIC) is responsible for the increase in maximum photoinduced currents generated with intensity of illumination.

Role of current algebra in B→pp-barπ(π)

International Nuclear Information System (INIS)

Paver, N.; Riazuddin.

1987-11-01

We estimate in a current algebra framework the hadronic matrix elements relevant to the weak B→pp-barπ(π) transitions measured recently. The results so obtained are in agreement with the observed values. (author). 11 refs, 1 fig

Wideband Precision Current Transformer for the Magnet Current of the Beam Extraction Kicker Magnet of the Large Hadron Collider

CERN Document Server

Gräwer, G

2004-01-01

The LHC beam extraction system is composed of 15 fast kicker magnets per beam to extract the particles in one turn of the collider and to safely dispose them on external absorbers. Each magnet is powered by a separate pulse generator. The generator produces a magnet current pulse with 3 us rise time, 20 kA amplitude and 1.8 ms fall time, of which 90 us are needed to dump the beam. The beam extraction system requires a high level of reliability. To detect any change in the magnet current characteristics, which might indicate a slow degradation of the pulse generator, a high precision wideband current transformer will be installed. For redundancy reasons, the results obtained with this device will be cross-checked with a Rogowski coil, installed adjacent to the transformer. A prototype transformer has been successfully tested at nominal current levels and showed satisfactory results compared with the output of a high frequency resistive coaxial shunt. The annular core of the ring type transformer is composed of...

Analysis of results obtained from field tracing test under natural rain condition

International Nuclear Information System (INIS)

Mukai, M.; Kamiyama, H.; Tanaka, T.; Wang Zhiming; Zhao Yingjie; Li Zhengtang

1993-01-01

As one of the tests arranged by the cooperative research between CIRP and JAERI, field tracing tests using 3 H, 60 Co, 85 Sr and 134 Cs were conducted in pits at the CIRP's field test site located on a loess tableland under natural rain condition. Precipitation amount and evaporation rate were measured to study complicated spatial-temporal behavior of soil water movement under that condition. The evaporation rate was obtained through an analysis on the measured data by a combined method of heat balance and eddy correlation. Numerical model, that is based on piston flow assumption of soil water movement, was developed and applied to determine the behavior of the soil water movement in the pits. Using the determined water movement, 3 H migration was evaluated by numerical simulation. Change of 3 H distribution as a function of elapsed time as well explained by careful evaluation of the soil water movement that carried out before the analysis. (5 figs.)

Optimizing Methods of Obtaining Stellar Parameters for the H3 Survey

Science.gov (United States)

Ivory, KeShawn; Conroy, Charlie; Cargile, Phillip

2018-01-01

The Stellar Halo at High Resolution with Hectochelle Survey (H3) is in the process of observing and collecting stellar parameters for stars in the Milky Way's halo. With a goal of measuring radial velocities for fainter stars, it is crucial that we have optimal methods of obtaining this and other parameters from the data from these stars.The method currently developed is The Payne, named after Cecilia Payne-Gaposchkin, a code that uses neural networks and Markov Chain Monte Carlo methods to utilize both spectra and photometry to obtain values for stellar parameters. This project was to investigate the benefit of fitting both spectra and spectral energy distributions (SED). Mock spectra using the parameters of the Sun were created and noise was inserted at various signal to noise values. The Payne then fit each mock spectrum with and without a mock SED also generated from solar parameters. The result was that at high signal to noise, the spectrum dominated and the effect of fitting the SED was minimal. But at low signal to noise, the addition of the SED greatly decreased the standard deviation of the data and resulted in more accurate values for temperature and metallicity.

SIMULATION OF THE DISTILLATION BY PRESSURE REDUCTION TO OBTAIN ANHYDROUS ETHANOL

Directory of Open Access Journals (Sweden)

Yeney Lauzurique Guerra

2016-10-01

Full Text Available In this work the distillation by pressure reduction was evaluated through the HYSYS v3.2 process simulator. Due to the lack of data in the consulted bibliography to perform the simulation, the STATGRAPHICS Centurion XVI software was used to obtain a response surface that would define optimal operating conditions. The property package selected to work was based on the Margules model. An anhydrous ethanol molar composition of 0.9917 was obtained. Temperature profiles were analyzed as well as liquid and vapor molar flows and dehydration column composition profiles. The influence of operating parameters on the efficiency of simulated technology was determined by analyzing one case study. According to economic evaluation, the implementation of this technology is not economically profitable; taking into account current prices and costs mostly due to high energy consumption and construction costs of the tower. This result contributes to the pursuit of other profitable technologies from the economic point of view.

Investigating the computer analysis of eddy current NDT data

International Nuclear Information System (INIS)

Brown, R.L.

1979-01-01

The objective of this activity was to investigate and develop techniques for computer analysis of eddy current nondestructive testing (NDT) data. A single frequency commercial eddy current tester and a precision mechanical scanner were interfaced with a PDP-11/34 computer to obtain and analyze eddy current data from samples of 316 stainless steel tubing containing known discontinuities. Among the data analysis techniques investigated were: correlation, Fast Fourier Transforms (FFT), clustering, and Adaptive Learning Networks (ALN). The results were considered encouraging. ALN, for example, correctly identified 88% of the defects and non-defects from a group of 153 signal indications

Numerical modeling of lower hybrid heating and current drive

International Nuclear Information System (INIS)

Valeo, E.J.; Eder, D.C.

1986-03-01

The generation of currents in toroidal plasma by application of waves in the lower hybrid frequency range involves the interplay of several physical phenomena which include: wave propagation in toroidal geometry, absorption via wave-particle resonances, the quasilinear generation of strongly nonequilibrium electron and ion distribution functions, and the self-consistent evolution of the current density in such a nonequilibrium plasma. We describe a code, LHMOD, which we have developed to treat these aspects of current drive and heating in tokamaks. We present results obtained by applying the code to a computation of current ramp-up and to an investigation of the possible importance of minority hydrogen absorption in a deuterium plasma as the ''density limit'' to current drive is approached

Current and future delivery of diagnostic electron microscopy in the UK: results of a national survey.

Science.gov (United States)

de Haro, Tracey; Furness, Peter

2012-04-01

Electron microscopy (EM) remains essential to delivering several specialist areas of diagnosis, especially the interpretation of native renal biopsies. However, there is anecdotal evidence of EM units struggling to survive, for a variety of reasons. The authors sought to obtain objective evidence of the extent and the causes of this problem. An online survey was undertaken of Fellows of the Royal College of Pathologists who use EM in diagnosis. A significant number of EM units anticipate having to close and hence outsource their EM work in the coming years. Yet most existing units are working to full capacity and would be unable to take on the substantial amounts of extra work implied by other units outsourcing their needs. Equipment and staffing are identified by most EM units as the major barriers to growth and are also the main reasons cited for units facing potential closure. In the current financial climate it seems unlikely that units will be willing to make the large investment in equipment and staff needed to take on extra work, unless they can be reasonably confident of an acceptable financial return as a result of increased external referral rates. The case is thus made for a degree of national coordination of the future provision of this specialist service, possibly through the National Commissioning Group or the new National Commissioning Board. Without this, the future of diagnostic EM services in the UK is uncertain. Its failure would pose a threat to good patient care.

Field-emission from parabolic tips: Current distributions, the net current, and effective emission area

Science.gov (United States)

Biswas, Debabrata

2018-04-01

Field emission from nano-structured emitters primarily takes place from the tips. Using recent results on the variation of the enhancement factor around the apex [Biswas et al., Ultramicroscopy 185, 1-4 (2018)], analytical expressions for the surface distribution of net emitted electrons, as well as the total and normal energy distributions are derived in terms of the apex radius Ra and the local electric field at the apex Ea. Formulae for the net emitted current and effective emission area in terms of these quantities are also obtained.

Dynamics of a plasma shell with a carrying out current

International Nuclear Information System (INIS)

Komel'kov, V.S.; Kuznetsov, A.P.; Perebejnos, V.V.; Pleshanov, A.S.; Solomonov, M.T.

1982-01-01

Experimental data on hydrogen plasma acceleration in continuous medium after plasma escape out from the coaxial plasma accelerator with discharge current approximately 1 MA and initial gas pressure approximately 10 4 Pa are obtained. Modified method of particle calculation in cells qualitatively satisfactorily describes the experiment and indicate a number of quantitative regularities of the process. The investigation made it possible to obtain qualitative characteristics on hydrogen plasma flow and displayed a number of quantitative regularities. Calculation results show the real possibility to obtain high-temperature dense plasma in continuous medium beyond the accelerator boundary

The use of human samples obtained during medicolegal autopsies in research: An introduction to current conditions and initiatives in Japan.

Science.gov (United States)

Tsujimura-Ito, Takako; Inoue, Yusuke; Muto, Kaori; Yoshida, Ken-Ichi

2017-04-01

Background Leftover samples obtained during autopsies are extremely important basic materials for forensic research. However, there are no established practices for research-related use of obtained samples. Objective This study discusses good practice for the secondary use of samples collected during medicolegal autopsies. Methods A questionnaire was posted to all 76 departments of forensic medicine performing medicolegal autopsies in Japan, and 48 responses were received (response rate: 63.2%). As a secondary analysis, we surveyed information provided on department websites. Results Ethical reviews conducted when samples were to be used for research varied greatly among departments, with 21 (43.8%) departments reporting 'fundamentally, all cases are subject to review', eight (16.7%) reporting 'only some are subject to review' and 17 (39.6%) reporting 'none are subject to review'. Information made available on websites indicated that 11 departments had a statement of some type to bereaved families about the potential research use of human samples obtained during autopsies. Nine of these included a notice stating that bereaved families may revoke their consent for use. Several departments used an opt-out system. Conclusion There is no common practice in the field of legal medicine on the ethical use for medical research of leftover samples from medicolegal autopsies. The trust of not only bereaved families but also society in general is required for the scientific validity and social benefits of medical studies using leftover samples from medicolegal autopsies through the use of opt-out consenting and offline and online dissemination and public-relations activities.

Terahertz spectroscopy of shift currents resulting from asymmetric (110)-oriented GaAs/AlGaAs quantum wells

International Nuclear Information System (INIS)

Priyadarshi, Shekhar; Leidinger, Markus; Pierz, Klaus; Racu, Ana M.; Siegner, Uwe; Bieler, Mark; Dawson, Philip

2009-01-01

We report the observation and the study of an additional shift current tensor element in (110)-oriented GaAs quantum wells, which arises from an out-of-plane asymmetry of the quantum well structure. The current resulting from this tensor element is optically induced with 150 fs laser pulses and detected by measuring the simultaneously emitted terahertz radiation. This terahertz spectroscopy of shift currents is a powerful technique for symmetry investigations, which shows, for example, that our nominally symmetric (110)-oriented GaAs/AlGaAs quantum wells grown by molecular beam epitaxy are in reality asymmetric structures with different right and left interfaces.

Higher spin currents in the orthogonal coset theory

Energy Technology Data Exchange (ETDEWEB)

Ahn, Changhyun [Kyungpook National University, Department of Physics, Taegu (Korea, Republic of)

2017-06-15

In the coset model (D{sub N}{sup (1)} + D{sub N}{sup (1)}, D{sub N}{sup (1)}) at levels (k{sub 1}, k{sub 2}), the higher spin 4 current that contains the quartic WZW currents contracted with a completely symmetric SO(2N) invariant d tensor of rank 4 is obtained. The three-point functions with two scalars are obtained for any finite N and k{sub 2} with k{sub 1} = 1. They are determined also in the large N 't Hooft limit. When one of the levels is the dual Coxeter number of SO(2N), k{sub 1} = 2N - 2, the higher spin (7)/(2) current, which contains the septic adjoint fermions contracted with the above d tensor and the triple product of structure constants, is obtained from the operator product expansion (OPE) between the spin (3)/(2) current living in the N = 1 superconformal algebra and the above higher spin 4 current. The OPEs between the higher spin (7)/(2), 4 currents are described. For k{sub 1} = k{sub 2} = 2N - 2 where both levels are equal to the dual Coxeter number of SO(2N), the higher spin 3 current of U(1) charge (4)/(3), which contains the six products of spin (1)/(2) (two) adjoint fermions contracted with the product of the d tensor and two structure constants, is obtained. The corresponding N = 2 higher spin multiplet is determined by calculating the remaining higher spin (7)/(2), (7)/(2), 4 currents with the help of two spin (3)/(2) currents in the N = 2 superconformal algebra. The other N = 2 higher spin multiplet, whose U(1) charge is opposite to the one of the above N = 2 higher spin multiplet, is obtained. The OPE between these two N = 2 higher spin multiplets is also discussed. (orig.)

Recent progress in lower hybrid current drive theory and experiments

International Nuclear Information System (INIS)

Barbato, E.

1998-01-01

In this paper lower hybrid current drive (LHCD) experimental milestones paving the way for future experiments are briefly summarized. The current drive efficiency scaling with the electron temperature is discussed. The role of wave propagation in determining the power deposition profile is stressed and methods are discussed to control the current density profile. Modelling of negative central shear configurations, experimentally obtained by LHCD, are reported. A good agreement is found between the modelling results and the experimental findings, thus showing that a good degree of understanding has been achieved in LHCD theory. (author)

Evaluation of instrumental parameters for obtaining acceptable analytical results of the Dosimetry Laboratory of Chemistry of the Regional Center of Nuclear Sciences, CNEN-NE, Recife, Brazil

International Nuclear Information System (INIS)

Souza, V.L.B.; Figueiredo, M.D.C.; Cunha, M.S.

2008-01-01

Instrumental parameters need to be evaluated for obtaining acceptable analytical results for a specific instrument. The performance of the UV-VIS spectrophotometer can be verified for wavelengths and absorbances with appropriate materials (solutions of different concentrations of K 2 CrO 4 , for example). The aim of this work was to demonstrate the results of the procedures to control the quality of the measurements carried out in the laboratory in the last four years. The samples were analyzed in the spectrophotometer and control graphics were obtained for K 2 CrO 4 and Fe 3+ absorbance values. The variation in the results obtained for the stability of the spectrophotometer and for the control of its calibration did not exceed 2%. (author)

Breeze Gravity Current in a Uniform Flow of Air

Directory of Open Access Journals (Sweden)

M.V. Shokurov

2017-02-01

Full Text Available Breeze circulation is often observed nearby the water basin coasts and usually accompanied by a background synoptic wind. One of the basic dynamically important components of the breeze circulation is gravity current. In the present paper the latter is used as the breeze simplified model. The theory of interaction of gravity current and a uniform synoptic wind are developed. The gravity current in the domain of infinite height in a stationary environment and environment with background flow was considered. To solve this problem the law of conservation of mass and universal property of the Froude number was used, which is true in the steady state. It is shown that increase of a tail-wind is followed by growth of the gravity current velocity and decrease of its height. The opposite situation is observed at increase of a head wind: the current velocity reduces and its height increases. Using a Taylor series expansion for small values of the background flow velocity a linear dependence of gravity current velocity on background flow velocity can be obtained. The factor determining the slope of the velocity of gravity current propagation on the background wind speed, which is equal 2/3, is a universal constant. The theory explains the results of numerical simulation previously obtained by numerous authors. A physical interpretation of dependence of the height and velocity of the gravity current on the background flow velocity is presented.

Iterative reconstruction for quantitative computed tomography analysis of emphysema: consistent results using different tube currents

Directory of Open Access Journals (Sweden)

Yamashiro T

2015-02-01

Full Text Available Tsuneo Yamashiro,1 Tetsuhiro Miyara,1 Osamu Honda,2 Noriyuki Tomiyama,2 Yoshiharu Ohno,3 Satoshi Noma,4 Sadayuki Murayama1 On behalf of the ACTIve Study Group 1Department of Radiology, Graduate School of Medical Science, University of the Ryukyus, Nishihara, Okinawa, Japan; 2Department of Radiology, Osaka University Graduate School of Medicine, Suita, Osaka, Japan; 3Department of Radiology, Kobe University Graduate School of Medicine, Kobe, Hyogo, Japan; 4Department of Radiology, Tenri Hospital, Tenri, Nara, Japan Purpose: To assess the advantages of iterative reconstruction for quantitative computed tomography (CT analysis of pulmonary emphysema. Materials and methods: Twenty-two patients with pulmonary emphysema underwent chest CT imaging using identical scanners with three different tube currents: 240, 120, and 60 mA. Scan data were converted to CT images using Adaptive Iterative Dose Reduction using Three Dimensional Processing (AIDR3D and a conventional filtered-back projection mode. Thus, six scans with and without AIDR3D were generated per patient. All other scanning and reconstruction settings were fixed. The percent low attenuation area (LAA%; < -950 Hounsfield units and the lung density 15th percentile were automatically measured using a commercial workstation. Comparisons of LAA% and 15th percentile results between scans with and without using AIDR3D were made by Wilcoxon signed-rank tests. Associations between body weight and measurement errors among these scans were evaluated by Spearman rank correlation analysis. Results: Overall, scan series without AIDR3D had higher LAA% and lower 15th percentile values than those with AIDR3D at each tube current (P<0.0001. For scan series without AIDR3D, lower tube currents resulted in higher LAA% values and lower 15th percentiles. The extent of emphysema was significantly different between each pair among scans when not using AIDR3D (LAA%, P<0.0001; 15th percentile, P<0.01, but was not

Preliminary results of the TBR small tokamak

International Nuclear Information System (INIS)

Nascimento, I.C.; Fagundes, A.N.; Da Silva, R.P.; Galvao, R.M.O.; Del Bosco, E.; Vuolo, J.H.; Sanada, E.K.; Dellaqua, R.

1982-01-01

The paper gives a short description of the TBR - small Brazilian tokamak and the first results obtained for plasma formation and equilibrium. Measured breakdown curves for hydrogen are shown to be confined within analytically calculated limits and to depend strongly on stray vertical magnetic fields. Time profiles of plasma current in equilibrium are shown and compared with the predictions of a simple analytical model for tokamak discharges. Reasonable agreement is obtained taking Zsub(eff) as a free parameter. (author)

Aero thermal test results obtained on the n. C 5 EL 4 Cluster in the atmospheric pressure cell

International Nuclear Information System (INIS)

Gasc, B.

1964-01-01

In the framework of thermal studies on the EL-4 cluster, the full-scale tests at atmospheric pressure are designed to permit measurement of local values of the wall temperature, of the velocity and of the temperature in the fluid. The experimental results, obtained with the help of an original measuring apparatus, make it possible to follow the changes in these values along the cluster and to predict in much detail the in-pile thermal behaviour. In particular it is shown that changes in the wall temperature along the cluster are greatly influenced by disruption of the flow caused by grids and supports. (author) [fr

Model for ICRF fast wave current drive in self-consistent MHD equilibria

International Nuclear Information System (INIS)

Bonoli, P.T.; Englade, R.C.; Porkolab, M.; Fenstermacher, M.E.

1993-01-01

Recently, a model for fast wave current drive in the ion cyclotron radio frequency (ICRF) range was incorporated into the current drive and MHD equilibrium code ACCOME. The ACCOME model combines a free boundary solution of the Grad Shafranov equation with the calculation of driven currents due to neutral beam injection, lower hybrid (LH) waves, bootstrap effects, and ICRF fast waves. The equilibrium and current drive packages iterate between each other to obtain an MHD equilibrium which is consistent with the profiles of driven current density. The ICRF current drive package combines a toroidal full-wave code (FISIC) with a parameterization of the current drive efficiency obtained from an adjoint solution of the Fokker Planck equation. The electron absorption calculation in the full-wave code properly accounts for the combined effects of electron Landau damping (ELD) and transit time magnetic pumping (TTMP), assuming a Maxwellian (or bi-Maxwellian) electron distribution function. Furthermore, the current drive efficiency includes the effects of particle trapping, momentum conserving corrections to the background Fokker Planck collision operator, and toroidally induced variations in the parallel wavenumbers of the injected ICRF waves. This model has been used to carry out detailed studies of advanced physics scenarios in the proposed Tokamak Physics Experiment (TPX). Results are shown, for example, which demonstrate the possibility of achieving stable equilibria at high beta and high bootstrap current fraction in TPX. Model results are also shown for the proposed ITER device

Current state of the art of HNF based composite propellants

NARCIS (Netherlands)

Ciucci, A.; Frota, O.; Welland, W.H.M.; Heijden, A.E.D.M. van der; Leeming, B.; Bellerby, J.M.; Brotzu, A.

2004-01-01

The main activities currently performed for the development of HNF-based propellants are presented. The objectives and approach adopted are described. The results obtained on the HNF decomposition mechanism and on the re- and co-crystallisation of HNF with potential propellant ingredients are

Lower hybrid wave current ramp-up and plasma equilibrium

International Nuclear Information System (INIS)

Gong Xueyu

1996-01-01

Questions on lower hybrid driven current and plasma equilibrium are studied. With the induced electric field taken into account, a system of self-consistent equations is obtained. This theory has been applied to some moments of the current ramp-up phase for the Tokamak Engineering Test Breeder (TETB) to study the lower hybrid current drive and MHD equilibrium. So, better electron current and safety factor profiles are obtained

Nonlinear current diffusion in type-II superconductors

International Nuclear Information System (INIS)

Beek, C.J. van der; Nieuwenhuys, G.J.; Kes, P.H.; Schnack, H.G.; Griessen, R.

1992-01-01

The temporal evolution of flux profiles in superconducting slabs and cylinders is investigated numerically for the situation where the flux-creep activation barrier U depends explicitly on current density j, e.g., U(j) ∝ [(j c /j) μ -1] or U(j)∝ln(j c /j). Both field-independent and field-dependent forms of the critical current density j c are considered. Exact numerical results for the time-dependent magnetization and relaxation time τ are compared to approximate analytical solutions. When the flux-creep activation barrier diverges as j → 0, flux- and current-density profiles evolve towards an asymptotic behaviour that is independent of initial conditions. The time-dependent magnetization in the case of full flux penetration is then well described by the appropriate form for the magnetization of the sample in the critical state, but with a time-dependent surface current density replacing the critical current density. The current-dependent flux-creep activation barrier may be obtained from low-temperature experiments using the analysis method of Maley et al., even when j c depends explicitly on B. (orig.)

Excessive current in wide superconducting films

International Nuclear Information System (INIS)

Volotskaya, V.G.; Sivakov, A.G.; Turutanov, O.G.

1986-01-01

The resistive state of a wide long film due to superconductivity destruction by current is studied. The voltage-independent excess current I 0 is observed on I-V curves at high transport currents. The two-dimensional image of the current-carrying sample obtained by laser scanning technique in this current range indicates that the whole film is in the resistive state. The current I 0 is measured as a function of magnetic field and SHF power

Suppression of Noise to Obtain a High-Performance Low-Cost Optical Encoder

Directory of Open Access Journals (Sweden)

Sergio Alvarez-Rodríguez

2018-01-01

Full Text Available Currently, commercial encoders endowed with high precision are expensive sensors, and optical low-cost designs to measure the positioning angle have undesirable levels of system noise which reduce the good performance of devices. This research is devoted to the designing of mathematical filters to suppress noise in polarized transducers, in order to obtain high accuracy, precision, and resolution, along with an adaptive maximum response speed for low-cost optical encoders. This design was proved through a prototype inside a research platform, and experimental results show an accuracy of 3.9, a precision of 26, and a resolution of 17 [arc seconds], at least for the specified working conditions, for the sensing of the angular position of a rotary polarizer. From this work has been obtained a high-performance low-cost polyphase optical encoder, which uses filtering mathematical principles potentially generalizable to other inventions.

Possible room temperature superconductivity in conductors obtained by bringing alkanes into contact with a graphite surface

Directory of Open Access Journals (Sweden)

Yasushi Kawashima

2013-05-01

Full Text Available Electrical resistances of conductors obtained by bringing alkanes into contact with a graphite surface have been investigated at room temperatures. Ring current in a ring-shaped container into which n-octane-soaked thin graphite flakes were compressed did not decay for 50 days at room temperature. After two HOPG plates were immersed into n-heptane and n-octane at room temperature, changes in resistances of the two samples were measured by four terminal technique. The measurement showed that the resistances of these samples decrease to less than the smallest resistance that can be measured with a high resolution digital voltmeter (0.1μV. The observation of persistent currents in the ring-shaped container suggests that the HOPG plates immersed in n-heptane and n-octane really entered zero-resistance state at room temperature. These results suggest that room temperature superconductor may be obtained by bringing alkanes into contact with a graphite surface.

Current algebra, statistical mechanics and quantum models

Science.gov (United States)

Vilela Mendes, R.

2017-11-01

Results obtained in the past for free boson systems at zero and nonzero temperatures are revisited to clarify the physical meaning of current algebra reducible functionals which are associated to systems with density fluctuations, leading to observable effects on phase transitions. To use current algebra as a tool for the formulation of quantum statistical mechanics amounts to the construction of unitary representations of diffeomorphism groups. Two mathematical equivalent procedures exist for this purpose. One searches for quasi-invariant measures on configuration spaces, the other for a cyclic vector in Hilbert space. Here, one argues that the second approach is closer to the physical intuition when modelling complex systems. An example of application of the current algebra methodology to the pairing phenomenon in two-dimensional fermion systems is discussed.

Current issues in electromagnetic knockout reactions

International Nuclear Information System (INIS)

Giusti, C.

2002-01-01

The role of correlations and two-body currents in one-nucleon emission reactions induced by an electromagnetic probe is discussed. The theoretical framework for cross section calculations is outlined and some results are presented for the exclusive "1"6O(e,e'p) "1"5N and "1"6O(γ, p) "1"5N reactions in relativistic and nonrelativistic models. A reliable and consistent evaluation of different types of correlations is needed to determine the spectroscopic factors. A consistent description of (e,e'p) and (γ, p) data, with the same spectroscopic factors, can be obtained when meson-exchange currents (MEC) are included in the theoretical model. MEC give an important contribution to (γ, p) cross sections and have only a small effect in (e, e'p). In the relativistic model the two-body seagull current affects the calculated cross sections less than in the nonrelativistic calculations.

The low-current low-temperature plasma generators

International Nuclear Information System (INIS)

Dautov, G.Yu.

2000-01-01

In this article, the results of low-current gas-discharge plasma generator investigations carried out by a group of scientists from the Kazan' Aviation Institute are presented. When considered necessary, the results are compared with the data obtained by other authors. The basic configurations and theoretical calculation peculiarities of plasma generators are described. The electrical, thermal and energy characteristics of discharges in gas flows, as well as summarised empirical formulae and experimental data necessary for calculations and design of plasma devices are presented. (author)

Machining tools in AISI M2 high-speed steel obtained by spray forming process

International Nuclear Information System (INIS)

Jesus, Edilson Rosa Barbosa de.

2004-01-01

The aim of the present work was the obtention of AISI M2 high-speed steel by spray forming technique and the material evaluation when used as machining tool. The obtained material was hot rolled at 50% and 72% reduction ratios, and from which it was manufactured inserts for machining tests. The performance of inserts made of the spray formed material was compared to inserts obtained from conventional and powder metallurgy (MP) processed materials. The spray formed material was chemical, physical, mechanical and microstructural characterised. For further characterisation, the materials were submitted to machining tests for performance evaluation under real work condition. The results of material characterisation highlight the potential of the spray forming technique, in the obtention of materials with good characteristics and properties. Under the current processing, hot rolling and heat treatments condition, the analysis of the results of the machining tests revealed a very similar behaviour among the tested materials. Proceeding a criterious analysis of the machining results tests, it was verified that the performance presented by the powder metallurgy material (MP) was slight superior, followed by conventional obtained material (MConv), which presented a insignificant advantage over the spray formed and hot rolled (72% reduction ratio) material. The worst result was encountered for the spray forming and hot rolled (50% reduction ratio) material that presented the highest wear values. (author)

Wave-current interaction in Willapa Bay

Science.gov (United States)

Olabarrieta, Maitane; Warner, John C.; Kumar, Nirnimesh

2011-01-01

This paper describes the importance of wave-current interaction in an inlet-estuary system. The three-dimensional, fully coupled, Coupled Ocean-Atmosphere-Wave-Sediment Transport (COAWST) modeling system was applied in Willapa Bay (Washington State) from 22 to 29 October 1998 that included a large storm event. To represent the interaction between waves and currents, the vortex-force method was used. Model results were compared with water elevations, currents, and wave measurements obtained by the U.S. Army Corp of Engineers. In general, a good agreement between field data and computed results was achieved, although some discrepancies were also observed in regard to wave peak directions in the most upstream station. Several numerical experiments that considered different forcing terms were run in order to identify the effects of each wind, tide, and wave-current interaction process. Comparison of the horizontal momentum balances results identified that wave-breaking-induced acceleration is one of the leading terms in the inlet area. The enhancement of the apparent bed roughness caused by waves also affected the values and distribution of the bottom shear stress. The pressure gradient showed significant changes with respect to the pure tidal case. During storm conditions the momentum balance in the inlet shares the characteristics of tidal-dominated and wave-dominated surf zone environments. The changes in the momentum balance caused by waves were manifested both in water level and current variations. The most relevant effect on hydrodynamics was a wave-induced setup in the inner part of the estuary.

Obtaining and Characterization of Flux-Based Products

Directory of Open Access Journals (Sweden)

Cosmina Maria Bogăţean

2015-11-01

Full Text Available The purpose of creating this assortment was to remind the public of a long forgotten sugar based product, with a high energy value and which can be easily associated both with plain or mineral water consumption. Also we have taken into consideration the well-known '' home-made'' and ''vintage'' concepts. The purpose of this scientific research is to obtain a laboratory created product, as well as obtaining both the cocoa and the lemon sorbet. In the technological process this type of products can be redefined under a new form. The great advantage comes with the fact that it dosen't currently exit on the market and so it can be considered as being a brand new product. The anbalyses both on the raw materials and on the final deliverable product were done in the Faculty's laboratories and it was proven to meet the standars.

Current-induced Rashba spin orbit torque in silicene

Energy Technology Data Exchange (ETDEWEB)

Chen, Ji, E-mail: muze7777@hdu.edu.cn [Department of Mathematics, School of Science, Hangzhou Dianzi University, Hangzhou 310018 (China); Peng, Yingzi [Department of Physics, School of Science, Hangzhou Dianzi University, Hangzhou 310018 (China); Center for Integrated Spintronic Devices, Hangzhou Dianzi University, Hangzhou 310018 (China); Zhou, Jie [Department of Mathematics, School of Science, Hangzhou Dianzi University, Hangzhou 310018 (China)

2017-06-15

Highlights: • The spin dynamics of a ferromagnetic layer coupled to a silicene is investigated. • The Rashba spin orbit torque is obtained and the well-known LLG equation is modified. • The explicit forms of spin orbit torques in Domain Wall and vortex is also obtained. - Abstract: We study theoretically the spin torque of a ferromagnetic layer coupled to a silicene in the presence of the intrinsic Rashba spin orbit coupling (RSOC) effect. By using gauge field method, we find that under the applied current, the RSOC can induce an effective field which will result in the spin precession of conduction electron without applying any magnetic field. We also derive the spin torques due to the RSOC, which generalize the Landau-Lifshitz-Gilbert (LLG) equation. The spin torques are related to the applied current, the carrier density and Rashba strength of the system.

Higher spin currents in Wolf space. Part I

Energy Technology Data Exchange (ETDEWEB)

Ahn, Changhyun [Department of Physics, Kyungpook National University,Taegu 702-701 (Korea, Republic of)

2014-03-20

For the N=4 superconformal coset theory described by ((SU(N+2))/(SU(N))) (that contains a Wolf space) with N=3, the N=2 WZW affine current algebra with constraints is obtained. The 16 generators of the large N=4 linear superconformal algebra are described by those WZW affine currents explicitly. By factoring out four spin-(1/2) currents and the spin-1 current from these 16 generators, the remaining 11 generators (spin-2 current, four spin-(3/2) currents, and six spin-1 currents) corresponding to the large N=4 nonlinear superconformal algebra are obtained. Based on the recent work by Gaberdiel and Gopakumar on the large N=4 holography, the extra 16 currents, with spin contents (1,(3/2),(3/2),2), ((3/2),2,2,(5/2)), ((3/2),2,2,(5/2)), and (2,(5/2),(5/2),3) described in terms of N=2 multiplets, are obtained and realized by the WZW affine currents. As a first step towards N=4W algebra (which is NOT known so far), the operator product expansions (OPEs) between the above 11 currents and these extra 16 higher spin currents are found explicitly. It turns out that the composite fields with definite U(1) charges, made of above (11+16) currents (which commute with the Wolf space subgroup SU(N=3)×SU(2)×U(1) currents), occur in the right hand sides of these OPEs.

Evaluation of the CDTN's cementation facility using the results obtained in two different sizes: laboratory and facility

International Nuclear Information System (INIS)

Haucz, Maria Judite A.; Calabria, Jaqueline A. Almeida; Tello, Cledola Cassia O.; Candido, Francisco Donizete; Seles, Sandro Rogerio Novaes

2011-01-01

At CDTN R and D activities generate low-level radioactive wastes, among them the aqueous liquid ones, which need special attention due to their volumes. The usual treatment for these wastes is the volume reduction process using chemicals in order to change the radionuclides of the waste to an insoluble form. The resultant sludge is incorporated into cement in 200-liter drums using an in-line batch mixing system (CDTN Cementation Facility). The process parameters and solidified product quality are evaluated at the Cementation Laboratory (LABCIM), where tests are carried out to determine the viscosity, set time and density of the paste. In addition of the visual examination, compressive strength test and density are also established in the solidified product. In the cementation facility some pastes are also prepared for the immobilization of non-compactable waste, such as dump, scrap metal, wood, and other ones. This paper aims to present the study comparing the results of tests done in the pastes and products prepared in LABCIM and the ones obtained in CDTN's cementation facility, in order to check the efficiency of the cementation system. (author)

Evaluation of the CDTN cementation facility using the results obtained in two different sizes: laboratory and facility

International Nuclear Information System (INIS)

Haucz, Maria Judite A.; Calabria, Jaqueline A. Almeida; Tello, Cledola Cassia O.; Candido, Francisco Donizete; Seles, Sandro Rogerio Novaes

2011-01-01

At CDTN R and D activities generate low-level radioactive wastes, among them the aqueous liquid ones, which need special attention due to their volumes. The usual treatment for these wastes is the volume reduction process using chemicals in order to change the radionuclides of the waste to an insoluble form. The resultant sludge is incorporated into cement in 200-liter drums using an in-line batch mixing system (CDTN Cementation Facility). The process parameters and solidified product quality are evaluated at the Cementation Laboratory (LABCIM), where tests are carried out to determine the viscosity, set time and density of the paste. In addition of the visual examination, compressive strength test and density are also established in the solidified product. In the cementation facility some pastes are also prepared for the immobilization of non-compactable waste, such as dump, scrap metal, wood, and other ones. This paper aims to present the study comparing the results of tests done in the pastes and products prepared in LABCIM and the ones obtained in CDTN's cementation facility, in order to check the efficiency of the cementation system. (author)

First in-core measurement results obtained with the innovative mobile calorimeter CALMOS inside the OSIRIS material testing reactor

International Nuclear Information System (INIS)

Carcreff, Hubert; Salmon, Laurent; Courtaux, Cedric

2014-01-01

Nuclear heating rate inside an MTR has to be known in order to design and to run irradiation experiments which have to fulfill target temperature constraints. This measurement is usually carried out by calorimetry. An innovative calorimetric system, CALMOS, has been studied and built in 2011 for the 70 MWth OSIRIS reactor operated by CEA. Thanks to a new calorimetric probe, associated to a specific displacement system, it provides measurements along the fissile height and above the core. Development of the calorimetric probe required manufacturing and irradiation of mock-ups in the ex-core area, where nuclear heating rate does not exceed 2 W.g -1 . The calorimeter working mode, the different measurement procedures, main modeling and ex-core experimental results have been already presented in previous papers. In this paper, we present in-core results obtained from 2011 to 2013 with the final device. For the first time, this new experimental measurement system was operated in several experimental locations, with nominal in-core thermal hydraulic conditions, nominal neutron flux and nuclear heating rate up to 6 W.g -1 (in graphite). After a brief presentation of the displacement system specificities, first nuclear heating distributions are presented and discussed. The Finite Element model of the calorimeter was upgraded in order to match calculated temperatures with measured ones. This 'validated' model allowed to estimate a Kc factor which tends to correct small nonlinearities when heating rate is calculated from the 'calibration method'. A comparison is made between nuclear heating rates determined from 'calibration' and 'zero methods'. In addition, an evaluation of the global uncertainty associated to the measurements is detailed. Finally, a comparison is made with available measurements obtained from previous calorimeters. (authors)

First In-Core Measurement Results Obtained with the Innovative Mobile Calorimeter CALMOS inside the OSIRIS Material Testing Reactor

International Nuclear Information System (INIS)

Carcreff, Hubert; Salmon, Laurent; Courtaux, Cedric

2013-06-01

Nuclear heating rate inside an MTR has to be known in order to design and to run irradiation experiments which have to fulfill target temperature constraints. This measurement is usually carried out by calorimetry [1, 2]. An innovative calorimetric system, CALMOS, has been studied and built in 2011 for the 70 MWth OSIRIS reactor operated by CEA. Thanks to a new calorimetric probe, associated to a specific displacement system, it provides measurements along the fissile height and above the core. The development of the calorimetric probe required the manufacturing and the irradiation of mock-ups in the ex-core area, where nuclear heating rate does not exceed 2 W.g -1 . The calorimeter working mode, the different measurement procedures allowed with such a new probe and main modeling and experimental results have been already presented [3, 4]. In this paper, we present the first results obtained during several measurement campaigns carried out in 2012 and 2013 inside the OSIRIS core with the final device. For the first time, this new experimental measurement system was operated in nominal in-core thermo hydraulic conditions with nominal neutron and gamma fluxes (up to 6 W.g -1 ) in several experimental locations. After a brief presentation of the displacement system specificities, first nuclear heating distributions are presented and discussed. Experimental data were also used to upgrade the Finite Element model of the calorimeter in order to match measured temperatures with calculated ones. This model allowed to estimate a Kc correction factor which takes into account small nonlinearities when the heating rate is deduced from the calibration method. A comparison is made between nuclear heating rates determined from the probe calibration and from the zero method. In addition, an evaluation of the global uncertainty associated to the measurements is detailed. Finally, a global comparison is made with available measurements obtained from previous calorimeters. (authors)

Low current beam techniques

Energy Technology Data Exchange (ETDEWEB)

Saint, A.; Laird, J.S.; Bardos, R.A.; Legge, G.J.F. [Melbourne Univ., Parkville, VIC (Australia). School of Physics; Nishijima, T.; Sekiguchi, H. [Electrotechnical Laboratory, Tsukuba (Japan).

1993-12-31

Since the development of Scanning Transmission Microscopy (STIM) imaging in 1983 many low current beam techniques have been developed for the scanning (ion) microprobe. These include STIM tomography, Ion Beam Induced Current, Ion Beam Micromachining and Microlithography and Ionoluminense. Most of these techniques utilise beam currents of 10{sup -15} A down to single ions controlled by beam switching techniques This paper will discuss some of the low beam current techniques mentioned above, and indicate, some of their recent applications at MARC. A new STIM technique will be introduced that can be used to obtain Z-contrast with STIM resolution. 4 refs., 3 figs.

Low current beam techniques

Energy Technology Data Exchange (ETDEWEB)

Saint, A; Laird, J S; Bardos, R A; Legge, G J.F. [Melbourne Univ., Parkville, VIC (Australia). School of Physics; Nishijima, T; Sekiguchi, H [Electrotechnical Laboratory, Tsukuba (Japan).

1994-12-31

Since the development of Scanning Transmission Microscopy (STIM) imaging in 1983 many low current beam techniques have been developed for the scanning (ion) microprobe. These include STIM tomography, Ion Beam Induced Current, Ion Beam Micromachining and Microlithography and Ionoluminense. Most of these techniques utilise beam currents of 10{sup -15} A down to single ions controlled by beam switching techniques This paper will discuss some of the low beam current techniques mentioned above, and indicate, some of their recent applications at MARC. A new STIM technique will be introduced that can be used to obtain Z-contrast with STIM resolution. 4 refs., 3 figs.

Langmuir probe characteristic in a current - carrying magnetized plasma

International Nuclear Information System (INIS)

Stanojevic, M.; Cercek, M.; Gyergyek, T.

1995-01-01

Experimental investigation of the Langmuir probe characteristic is a magnetized plasma with an electron current along the magnetic field direction shows that the standard procedure for determination of the electron temperature and plasma density, which is applicable in a current - free magnetized plasma, gives erroneous results for these plasma parameters. However, more precise values of the plasma parameters can be calculated from the ion saturation currents and electron temperatures obtained with that procedure for two opposite orientations of the one - sided planar probe collecting surface with respect to the direction of the electron drift. With the existing theoretical models only the order of magnitude of the electron drift velocity can be accurately determined from the measured electron saturation currents for the two probe orientations. (author)

Evaluation of Rock Powdering Methods to Obtain Fine-grained Samples for CHEMIN, a Combined XRD/XRF Instrument

Science.gov (United States)

Chipera, S. J.; Vaniman, D. T.; Bish, D. L.; Sarrazin, P.; Feldman, S.; Blake, D. F.; Bearman, G.; Bar-Cohen, Y.

2004-01-01

A miniature XRD/XRF (X-ray diffraction / X-ray fluorescence) instrument, CHEMIN, is currently being developed for definitive mineralogic analysis of soils and rocks on Mars. One of the technical issues that must be addressed to enable remote XRD analysis is how best to obtain a representative sample powder for analysis. For powder XRD analyses, it is beneficial to have a fine-grained sample to reduce preferred orientation effects and to provide a statistically significant number of crystallites to the X-ray beam. Although a two-dimensional detector as used in the CHEMIN instrument will produce good results even with poorly prepared powder, the quality of the data will improve and the time required for data collection will be reduced if the sample is fine-grained and randomly oriented. A variety of methods have been proposed for XRD sample preparation. Chipera et al. presented grain size distributions and XRD results from powders generated with an Ultrasonic/Sonic Driller/Corer (USDC) currently being developed at JPL. The USDC was shown to be an effective instrument for sampling rock to produce powder suitable for XRD. In this paper, we compare powder prepared using the USDC with powder obtained with a miniaturized rock crusher developed at JPL and with powder obtained with a rotary tungsten carbide bit to powders obtained from a laboratory bench-scale Retsch mill (provides benchmark mineralogical data). These comparisons will allow assessment of the suitability of these methods for analysis by an XRD/XRF instrument such as CHEMIN.

Influence of the Dermis Thickness on the Results of the Skin Treatment with Monopolar and Bipolar Radiofrequency Currents.

Science.gov (United States)

Kruglikov, Ilja L

2016-01-01

Electrically layered tissue structure significantly modifies distribution of radiofrequency (RF) current in the dermis and in the subcutaneous adipose tissue comparing to that in a homogeneous medium. On the basis of the simple model of RF current distribution in a two-layer skin containing dermis and subcutis, we assess the influence of the dermal thickness on the current density in different skin layers. Under other equal conditions, current density in the dermis is higher for the skin having thinner dermis. This contradicts the main paradigm of the RF theory stating that treatment results are mainly dependent on the maximal temperature reached in a target tissue, since the best short- and long-term clinical results of RF application to the skin were reported in the areas having thicker dermis. To resolve this contradiction, it is proposed that the long-term effect of RF can be realized through a structural modification of the subcutaneous fat depot adjacent to the treated skin area. Stimulation of these cells located near the interface dermis/subcutis will demand the concentration of applied RF energy in this area and will require the optimal arrangement of RF electrodes on the skin surface.

Influence of the Dermis Thickness on the Results of the Skin Treatment with Monopolar and Bipolar Radiofrequency Currents

Directory of Open Access Journals (Sweden)

Ilja L. Kruglikov

2016-01-01

Full Text Available Electrically layered tissue structure significantly modifies distribution of radiofrequency (RF current in the dermis and in the subcutaneous adipose tissue comparing to that in a homogeneous medium. On the basis of the simple model of RF current distribution in a two-layer skin containing dermis and subcutis, we assess the influence of the dermal thickness on the current density in different skin layers. Under other equal conditions, current density in the dermis is higher for the skin having thinner dermis. This contradicts the main paradigm of the RF theory stating that treatment results are mainly dependent on the maximal temperature reached in a target tissue, since the best short- and long-term clinical results of RF application to the skin were reported in the areas having thicker dermis. To resolve this contradiction, it is proposed that the long-term effect of RF can be realized through a structural modification of the subcutaneous fat depot adjacent to the treated skin area. Stimulation of these cells located near the interface dermis/subcutis will demand the concentration of applied RF energy in this area and will require the optimal arrangement of RF electrodes on the skin surface.

Definition of current density in the presence of a non-local potential.

Science.gov (United States)

Li, Changsheng; Wan, Langhui; Wei, Yadong; Wang, Jian

2008-04-16

In the presence of a non-local potential arising from electron-electron interaction, the conventional definition of current density J(c) = (e/2m)([(p-eA)ψ](*)ψ-ψ(*)[(p-eA)ψ]) cannot satisfy the condition of current conservation, i.e., [Formula: see text] in the steady state. In order to solve this problem, we give a new definition of current density including the contribution due to the non-local potential. We show that the current calculated based on the new definition of current density conserves the current and is the same as that obtained from the Landauer-Büttiker formula. Examples are given to demonstrate our results.

Definition of current density in the presence of a non-local potential

International Nuclear Information System (INIS)

Li Changsheng; Wan Langhui; Wei Yadong; Wang Jian

2008-01-01

In the presence of a non-local potential arising from electron-electron interaction, the conventional definition of current density J c = (e/2m)([(p-eA)ψ]*ψ-ψ*[(p-eA)ψ]) cannot satisfy the condition of current conservation, i.e., ∇ . J c ≠ 0 in the steady state. In order to solve this problem, we give a new definition of current density including the contribution due to the non-local potential. We show that the current calculated based on the new definition of current density conserves the current and is the same as that obtained from the Landauer-Buettiker formula. Examples are given to demonstrate our results

Higher spin currents in orthogonal Wolf space

International Nuclear Information System (INIS)

Ahn, Changhyun; Paeng, Jinsub

2015-01-01

For the N=4 superconformal coset theory by ((SO(N+4))/(SO(N)×SU(2)))×U(1) (that contains an orthogonal Wolf space) with N = 4, the N=2 WZW affine current algebra is obtained. The 16 generators (or 11 generators) of the large N=4 linear (or nonlinear) superconformal algebra are described by these WZW affine currents explicitly. Along the line of large N=4 holography, the extra 16 currents with spins (2,(5/2),(5/2),3), ((5/2),3,3,(7/2)), ((5/2),3,3,(7/2)), and (3,(7/2),(7/2),4) are obtained in terms of the WZW affine currents. The lowest spin of this N=4 multiplet is two rather than one, which is for a unitary Wolf space. The operator product expansions between the above 11 currents and these extra 16 higher spin currents are found explicitly. (paper)

Production, detection, storage and release of spin currents

Directory of Open Access Journals (Sweden)

Michele Cini

2015-03-01

Full Text Available Background: Quantum rings connected to ballistic circuits couple strongly to external magnetic fields if the connection is not symmetric. Moreover, properly connected rings can be used to pump currents in the wires giving raise to a number of interesting new phenomena. At half filling using a time-dependent magnetic field in the plane of the ring one can pump a pure spin current, excited by the the spin–orbit interaction in the ring.Results: Such a magnetic current is even under time reversal and produces an electric field instead of the usual magnetic field. Numerical simulations show that one can use magnetizable bodies as storage units to concentrate and save the magnetization in much the same way as capacitors operating with charge currents store electric charge. The polarization obtained in this way can then be used on command to produce spin currents in a wire. These currents show interesting oscillations while the storage units exchange their polarizations.Conclusion: The magnetic production of spin currents can be a useful alternative to optical excitation and electric field methods.

Preliminary observations and results obtained with the ultraviolet spectrometer and polarimeter. [for Solar Maximum Mission

Science.gov (United States)

Tandberg-Hassen, E.; Cheng, C. C.; Athay, R. G.; Beckers, J. M.; Brandt, J. C.; Chapman, R. D.; Bruner, E. C.; Henze, W.; Hyder, C. L.; Gurman, J. B.

1981-01-01

New observation with the Ultraviolet Spectrometer and Polarimeter (UVSP) of a number of manifestations of solar activity obtained during the first three months of Solar Maximum Mission operations are presented. Attention is given to polarimetry in sunspots, oscillations above sunspots, density diagnostics of transition-zone plasmas in active regions, and the eruptive prominence - coronal transient link.

Matching the results of a theoretical model with failure rates obtained from a population of non-nuclear pressure vessels

International Nuclear Information System (INIS)

Harrop, L.P.

1982-02-01

Failure rates for non-nuclear pressure vessel populations are often regarded as showing a decrease with time. Empirical evidence can be cited which supports this view. On the other hand theoretical predictions of PWR type reactor pressure vessel failure rates have shown an increasing failure rate with time. It is shown that these two situations are not necessarily incompatible. If adjustments are made to the input data of the theoretical model to treat a non-nuclear pressure vessel population, the model can produce a failure rate which decreases with time. These adjustments are explained and the results obtained are shown. (author)

Dynamics and stabilization of peak current-mode controlled buck converter with constant current load

Science.gov (United States)

Leng, Min-Rui; Zhou, Guo-Hua; Zhang, Kai-Tun; Li, Zhen-Hua

2015-10-01

The discrete iterative map model of peak current-mode controlled buck converter with constant current load (CCL), containing the output voltage feedback and ramp compensation, is established in this paper. Based on this model the complex dynamics of this converter is investigated by analyzing bifurcation diagrams and the Lyapunov exponent spectrum. The effects of ramp compensation and output voltage feedback on the stability of the converter are investigated. Experimental results verify the simulation and theoretical analysis. The stability boundary and chaos boundary are obtained under the theoretical conditions of period-doubling bifurcation and border collision. It is found that there are four operation regions in the peak current-mode controlled buck converter with CCL due to period-doubling bifurcation and border-collision bifurcation. Research results indicate that ramp compensation can extend the stable operation range and transfer the operating mode, and output voltage feedback can eventually eliminate the coexisting fast-slow scale instability. Project supported by the National Natural Science Foundation of China (Grant No. 61371033), the Fok Ying-Tung Education Foundation for Young Teachers in the Higher Education Institutions of China (Grant No. 142027), the Sichuan Provincial Youth Science and Technology Fund, China (Grant Nos. 2014JQ0015 and 2013JQ0033), and the Fundamental Research Funds for the Central Universities, China (Grant No. SWJTU11CX029).

Preliminary analysis of surface displacement results in the creepdown irradiation experiment HOBBIE-1

International Nuclear Information System (INIS)

Hobson, D.O.

1979-01-01

This report presents the results of the eddy-current surface displacement measurements of Zircaloy cladding obtained during the HOBBIE-1 irradiation experiment in the HFR at ECN-Petten, the Netherlands. Raw creepdown data from the test were corrected through the use of reference coils incorporated in the eddy-current coil block in the experiment capsule. The corrected displacement results are compared with out-of-reactor results obtained under nominally identical conditions of pressure and temperature. Experiment HOBBIE-1 was run at 371 0 C and 13.1 MPa specimen external pressure for a total time of approximately 950 h. No gross cladding ovalization was obtained. This result differed from the relatively simple ovality found in the out-of-reactor test. Contact with the internal mandrel occurred between 400 and 500 h, compared with 375 h for a comparable out-of-reactor test. Average diameter decreases for both tests were similar. These results are discussed in detail

Working harder to obtain more snack foods when wanting to eat less.

Science.gov (United States)

Giesen, Janneke C A H; Havermans, Remco C; Nederkoorn, Chantal; Strafaci, Silvana; Jansen, Anita

2009-01-01

This study investigates individual differences in the reinforcing value of snack food. More specifically, it was investigated whether differences in restraint status are associated with differences in working for high-caloric snack food. Thirty-six unrestrained non-dieters, twenty restrained non-dieters and fifteen current dieters performed a concurrent schedules task in which they had the option to work for points for either snack food or fruit and vegetables. By progressively increasing the "price" of the snack foods (i.e., the amount of work required to obtain extra snack points) the relative reinforcing value of snack food was determined. As hypothesized, restrained non-dieters worked harder and current dieters worked less hard to obtain snack food as compared to unrestrained non-dieters.

Critical power for lower hybrid current drive

International Nuclear Information System (INIS)

Assis, A.S. de; Sakanaka, P.H.; Azevedo, C.A. de; Busnardo-Neto, J.

1995-11-01

We have solved numerically the quasilinear Fokker-Planck equation which models the critical power for lower hybrid wave current drive. An exact value for the critical power necessary for current saturation, for tokamak current drive experiments, has been obtained. The nonlinear treatment presented here leads to a final profile for the parallel distribution function which is a plateau only in a part of the resonance region. This form of the distribution function is intermediate between two well known results: a plateau throughout the resonance region for the linear strong-source regime, D wave >> D coll and no plateau at all in the resonance region the linear weak-source regimen, D wave coll . The strength of the external power source and the value of the dc electric field are treated as given parameters in the integration scheme. (author). 24 refs, 6 figs

Global Ocean Currents Database (GOCD) (NCEI Accession 0093183)

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — The Global Ocean Currents Database (GOCD) is a collection of quality controlled ocean current measurements such as observed current direction and speed obtained from...

Light-cone gauge approach to arbitrary spin fields, currents and shadows

International Nuclear Information System (INIS)

Metsaev, R R

2014-01-01

Totally symmetric arbitrary spin fields in AdS space, conformal fields, conformal currents, and shadow fields in flat space are studied. Light-cone gauge formulations for such fields, currents and shadows are obtained. Use of the Poincaré parametrization of AdS space and ladder operators allows us to treat fields in flat and AdS spaces on an equal footing. Light-cone gauge realization of relativistic symmetries for fields, currents and shadows is also obtained. The light-cone gauge formulation for fields is obtained by using the gauge invariant Lagrangian which is presented in terms of modified de Donder divergence, while the light-cone gauge formulation for currents and shadows is obtained by using the gauge invariant approach to currents and shadows. This allows us to demonstrate explicitly how the ladder operators entering the gauge invariant formulation of fields, currents and shadows manifest themselves in the light-cone gauge formulation for fields, currents and shadows. (paper)

Diversification of the Industrial Use of the Land River Layer: Obtaining Aluminum Sulfate for Water Treatment

Directory of Open Access Journals (Sweden)

Leonardo Rodríguez-Suárez

2017-04-01

Full Text Available With the objective of obtaining aluminum sulphate to be used as a coagulant in the water treatment, experimental test works were conducted with a sample of the kaolin ore body Río del Callejón located in the special municipality of the Isle of Youth. The sample was characterized from the chemical and granulometric point of view and was subjected to a technological process with calcination and sulphuric acid leaching being the main operations. The Plackett–Burman screening design was used in the technological tests taking calcination temperature, calcination time, leaching temperature, leaching time, agitation velocity, acid concentration and liquid-solid ratio as independent variables. An aluminum sulphate with suitable characteristics to be used as a coagulant substance in water treatment (human consumption and residual was obtained. The experimental results revealed that the aluminum sulphate obtained shows better quality than that of the one currently obtained in the industry using aluminum hydroxide.

New Methods for Estimating Water Current Velocity Fields from Autonomous Underwater Vehicles

Science.gov (United States)

Kinsey, J. C.; Medagoda, L.

2016-02-01

Water current velocities are a crucial component of understanding oceanographic processes and underwater robots, such as autonomous underwater vehicles (AUVs), provide a mobile platform for obtaining these observations. Estimating water current velocities requires both measurements of the water velocity, often obtained with an Acoustic Doppler Current Profiler (ADCP), as well as estimates of the vehicle velocity. Presently, vehicle velocities are supplied on the sea surface with velocity from GPS, or near the seafloor where Doppler Velocity Log (DVL) in bottom-lock is available; however, this capability is unavailable in the mid-water column where DVL bottom-lock and GPS are unavailable. Here we present a method which calculates vehicle velocities using consecutive ADCP measurements in the mid-water using an extended Kalman filter (EKF). The correlation of the spatially changing water current states, along with mass transport and shear constraints on the water current field, is formulated using least square constraints. Results from the Sentry AUV from a mid-water surveying mission at Deepwater Horizon and a small-scale hydrothermal vent flux estimation mission suggest the method is suitable for real-time use. DVL data is denied to simulate mid-water missions and the results compared to ground truth water velocity measurements estimated using DVL velocities. Results show quantifiable uncertainties in the water current velocities, along with similar performance, for the DVL and no-DVL case in the mid-water. This method has the potential to provide geo-referenced water velocity measurements from mobile ocean robots in the absence of GPS and DVL as well as estimate the uncertainty associated with the measurements.

Ramp compression of a metallic liner driven by a shaped 5 MA current on the SPHINX machine

Science.gov (United States)

d'Almeida, T.; Lassalle, F.; Morell, A.; Grunenwald, J.; Zucchini, F.; Loyen, A.; Maysonnave, T.; Chuvatin, A.

2014-05-01

SPHINX is a 6MA, 1-us Linear Transformer Driver operated by the CEA Gramat (France) and primarily used for imploding Z-pinch loads for radiation effects studies. A method for performing magnetic ramp compression experiments was developed using a compact Dynamic Load Current Multiplier inserted between the convolute and the load, to shape the initial current pulse. We present the overall experimental configuration chosen for these experiments and initial results obtained over a set of experiments on an aluminum cylindrical liner. Current profiles measured at various critical locations across the system, are in good agreement with simulated current profiles. The liner inner free surface velocity measurements agree with the hydrocode results obtained using the measured load current as the input. The potential of the technique in terms of applications and achievable ramp pressure levels lies in the prospects for improving the DLCM efficiency.

Ramp compression of a metallic liner driven by a shaped 5 MA current on the SPHINX machine

International Nuclear Information System (INIS)

D'Almeida, T; Lassalle, F; Morell, A; Grunenwald, J; Zucchini, F; Loyen, A; Maysonnave, T; Chuvatin, A

2014-01-01

SPHINX is a 6MA, 1-us Linear Transformer Driver operated by the CEA Gramat (France) and primarily used for imploding Z-pinch loads for radiation effects studies. A method for performing magnetic ramp compression experiments was developed using a compact Dynamic Load Current Multiplier inserted between the convolute and the load, to shape the initial current pulse. We present the overall experimental configuration chosen for these experiments and initial results obtained over a set of experiments on an aluminum cylindrical liner. Current profiles measured at various critical locations across the system, are in good agreement with simulated current profiles. The liner inner free surface velocity measurements agree with the hydrocode results obtained using the measured load current as the input. The potential of the technique in terms of applications and achievable ramp pressure levels lies in the prospects for improving the DLCM efficiency.

Measurement of the ratios of neutral-current to charged current cross sections of neutrino and antineutrino interactions in Ne

Science.gov (United States)

Bosetti, P. C.; Fritze, P.; Grässler, H.; Hasert, F. J.; Schulte, R.; Schultze, K.; Geich-Gimbel, C.; Nellen, B.; Pech, R.; Wünsch, B.; Grant, A.; Hulth, P. O.; Klein, H.; Morrison, D. R. O.; Pape, L.; Wachsmuth, H.; Vayaki, A.; Barnham, K. W. J.; Beuselinck, R.; Clayton, E. F.; Miller, D. B.; Mobayyen, M. M.; Petrides, A.; Albajar, C.; Myatt, G.; Saitta, B.; Wells, J.; Bolognese, T.; Vignaud, D.; Aachen-Bonn-CERN-Democritos-Imperial College, London-Oxford-Saclay Collaboration

1983-05-01

The ratios of neutral current to charged current cross sections of neutrino and antineutrino interactions in heavy Ne/H 2 mixture have been measured in BEBC. The beam was the CERN SPS 200 GeV/ c narrow band beam. The ratios were obtained using a cut in the transverse momentum of the hadronic system. In the standard Glashow-Salam-Weinberg model, our results correspond to the value of sin 2θw = 0.182 ± 0.020 ± 0.012. By combining this experiment with data from a hydrogen target the coupling constants uL2 and L2 are found to be 0.15 ± 0.04 and 0.19 ± 0.05, respectively.

Measurement of the ratios of neutral-current to charged current cross sections of neutrino and antineutrino interactions in Ne

International Nuclear Information System (INIS)

Bosetti, P.C.; Fritze, P.; Graessler, H.; Hasert, F.J.; Schulte, R.; Schultze, K.; Vayaki, A.; Barnham, K.W.J.; Beuselinck, R.; Clayton, E.F.; Miller, D.B.; Mobayyen, M.M.; Petrides, A.; Albajar, C.; Myatt, G.; Saitta, B.; Wells, J.

1983-01-01

The ratios of neutral current to charged current cross sections of neutrino and antineutrino interactions in heavy Ne/H 2 mixture have been measured in BEBC. The beam was the CERN SPS 200 GeV/c narrow band beam. The ratios were obtained using a cut in the transverse momentum of the hadronic system. In the standard Glashow-Salam-Weinberg model, our results correspond to the value of sin 2 THETAsub(w)=0.182+-0.020+-0.012. By combining this experiment with data from a hydrogen target the coupling constants usub(L) 2 and dsub(L) 2 are found to be 0.15+-0.04 and 0.19+-0.05, respectively. (orig.)

Simulations of enhanced reversed shear TFTR discharges with lower hybrid current drive

International Nuclear Information System (INIS)

Kesner, J.; Bateman, G.

1996-01-01

The BALDUR based BBK code permits predictive simulations of time-dependent tokamak discharges and has the capability to include neutral beam heating, pellet injection, bootstrap currents and lower hybrid current drive. BALDUR contains a theory based multi-regime transport model and previous work has shown excellent agreement with both L-mode and supershot TFTR discharges. These simulations reveal that core transport is dominated by η i and trapped electron modes and the outer region by resistive ballooning. We simulate enhanced reverse shear discharges by beginning with a supershot simulation with a reversed shear profile. Similarly to the TFTR experiments the reversed shear profile is obtained through the programming of the current during startup and the freezing in of these profiles by subsequent heating. At the time of transition into the enhanced confinement regime we turn off the η i and trapped-electron mode transport. We examine the further modification of the plasma current profile that can be obtained with the application of lower hybrid current drive. The results of these simulations will be discussed

Analysis of results of AZTRAN and AZKIND codes for a BWR

International Nuclear Information System (INIS)

Bastida O, G. E.; Vallejo Q, J. A.; Galicia A, J.; Francois L, J. L.; Xolocostli M, J. V.; Rodriguez H, A.; Gomez T, A. M.

2016-09-01

This paper presents an analysis of results obtained from simulations performed with the neutron transport code AZTRAN and the kinetic code of neutron diffusion AZKIND, based on comparisons with models corresponding to a typical BWR, in order to verify the behavior and reliability of the values obtained with said code for its current development. For this, simulations of different geometries were made using validated nuclear codes, such as CASMO, MCNP5 and Serpent. The results obtained are considered adequate since they are comparable with those obtained and reported with other codes, based mainly on the neutron multiplication factor and the power distribution of the same. (Author)

Comparison between two sampling methods by results obtained using petrographic techniques, specially developed for minerals of the Itataia uranium phosphate deposit, Ceara, Brazil

International Nuclear Information System (INIS)

Salas, H.T.; Murta, R.L.L.

1985-01-01

The results of comparison of two sampling methods applied to a gallery of the uranium-phosphate ore body of Itataia-Ceara State, Brazil, along 235 metres of mineralized zone, are presented. The results were obtained through petrographic techniques especially developed and applied to both samplings. In the first one it was studied hand samples from a systematically sampling made at intervals of 2 metres. After that, the estimated mineralogical composition studies were carried out. Some petrogenetic observations were for the first time verified. The second sampling was made at intervals of 20 metres and 570 tons of ore extracted and distributed in sections and a sample representing each section was studied after crushing at -65. Their mineralogy were quantified and the degree of liberation of apatite calculated. Based on the mineralogical data obtained it was possible to represent both samplings and to make the comparison of the main mineralogical groups (phosphates, carbonates and silicates). In spite of utilizing different methods and methodology and the kind of mineralization, stockwork, being quite irregular, the results were satisfactory. (Author) [pt

Conduction mechanism of leakage current due to the traps in ZrO2 thin film

Science.gov (United States)

Seo, Yohan; Lee, Sangyouk; An, Ilsin; Song, Chulgi; Jeong, Heejun

2009-11-01

In this work, a metal-oxide-semiconductor capacitor with zirconium oxide (ZrO2) gate dielectric was fabricated by an atomic layer deposition (ALD) technique and the leakage current characteristics under negative bias were studied. From the result of current-voltage curves there are two possible conduction mechanisms to explain the leakage current in the ZrO2 thin film. The dominant mechanism is the space charge limited conduction in the high-electric field region (1.5-5.0 MV cm-1) while the trap-assisted tunneling due to the existence of traps is prevailed in the low-electric field region (0.8-1.5 MV cm-1). Conduction caused by the trap-assisted tunneling is found from the experimental results of a weak temperature dependence of current, and the trap barrier height is obtained. The space charge limited conduction is evidenced, for different temperatures, by Child's law dependence of current density versus voltage. Child's law dependence can be explained by considering a single discrete trapping level and we can obtain the activation energy of 0.22 eV.

Neutron induced current pulses in fission chambers

International Nuclear Information System (INIS)

Taboas, A.L.; Buck, W.L.

1978-01-01

The mechanism of neutron induced current pulse generation in fission chambers is discussed. By application of the calculated detector transfer function to proposed detector current pulse shapes, and by comparison with actually observed detector output voltage pulses, a credible, semi-empirical, trapezoidal pulse shape of chamber current is obtained

Measuring electric conductivity in liquid metals by eddy current method

International Nuclear Information System (INIS)

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%

Analysis of transient state in HTS tapes under ripple DC load current

Science.gov (United States)

Stepien, M.; Grzesik, B.

2014-05-01

The paper concerns the analysis of transient state (quench transition) in HTS tapes loaded with the current having DC component together with a ripple component. Two shapes of the ripple were taken into account: sinusoidal and triangular. Very often HTS tape connected to a power electronic current supply (i.e. superconducting coil for SMES) that delivers DC current with ripples and it needs to be examined under such conditions. Additionally, measurements of electrical (and thermal) parameters under such ripple excitation is useful to tape characterization in broad range of load currents. The results presented in the paper were obtained using test bench which contains programmable DC supply and National Instruments data acquisition system. Voltage drops and load currents were measured vs. time. Analysis of measured parameters as a function of the current was used to tape description with quench dynamics taken into account. Results of measurements were also used to comparison with the results of numerical modelling based on FEM. Presented provisional results show possibility to use results of measurements in transient state to prepare inverse models of superconductors and their detailed numerical modelling.

SnO2*CoO ceramic obtained by microwave sintering

International Nuclear Information System (INIS)

Bordignon, M.A.N; Moura, F.; Zaghete, M.A.; Varela, J.A.; Perazolli, L.

2009-01-01

This work consists in the sintering study of CoO doped SnO 2 using microwave sintering oven and silicon carbide as a susceptor. The powders were obtained by dry oxides mixture and conformed in cylindrical shapes with 6mmx8mm and green density to 60%. Then the compacts were sintering up to 1.050 deg C, using heating rate of 50 deg C/min and isotherm up to 30min. The densities obtained were above 95% for both techniques. It was observed that occurred a temperature reducing of 400 deg C and time reducing of 210min to obtain the same densities, when was used the microwave oven without the phenomena of thermal runaway. So the sintered compacts were accomplished using DRX and SEM. It was made the electrical characterization (current x voltage) and it was found to have great potential in the production of dense ceramic-based SnO 2 with low resistivity to obtain electro-ceramic devices. (author)

LEP and results obtained by DELPHI after four years of operation; LEP i wyniki uzyskane przez DELPHI po czterech latach dzialania

Energy Technology Data Exchange (ETDEWEB)

Blocki, J. [Warsaw Univ. (Poland). Inst. Fizyki Doswiadczalnej; Brueckman de Renstrom, P.; Budziak, A. [Institute of Nuclear Physics, Cracow (Poland)] [and others

1993-10-01

We characterize the most important problems of modern elementary particles physics, for the solution of which the LEP (Large Electron Positron) accelerator was built. We present the characteristics of this accelerator. The structure and properties of the DELPHI detector are described with special emphasis on the contribution of Polish groups. The most important results obtained so far in the LEP accelerator are discussed. (author). 12 refs, 17 figs, 1 tab.

Current-induced magnetic switching of a single molecule magnet on a spin valve

International Nuclear Information System (INIS)

Zhang, Xiao; Wang, Zheng-Chuan; Zheng, Qing-Rong; Zhu, Zheng-Gang; Su, Gang

2015-01-01

The current-induced magnetic switching of a single-molecule magnet (SMM) attached on the central region of a spin valve is explored, and the condition for the switching current is derived. Electrons flowing through the spin valve will interact with the SMM via the s–d exchange interaction, producing the spin accumulation that satisfies the spin diffusion equation. We further describe the spin motion of the SMM by a Heisenberg-like equation. Based on the linear stability analysis, we obtain the critical current from two coupled equations. The results of the critical current versus the external magnetic field indicate that one can manipulate the magnetic state of the SMM by an external magnetic field. - Highlights: • We theoretically study the current-induced magnetic switching of the SMM. • We describe the spin motion of the SMM by a Heisenberg-like equation. • We describe the spin accumulation by the spin diffusion equation. • We obtain the critical current by the linear stability analysis. • Our approach can be easily extended to other SMMs

Current-induced magnetic switching of a single molecule magnet on a spin valve

Energy Technology Data Exchange (ETDEWEB)

Zhang, Xiao [Theoretical Condensed Matter Physics and Computational Materials Physics Laboratory, School of Physics, University of Chinese Academy of Sciences, Beijing 100049 (China); Wang, Zheng-Chuan, E-mail: wangzc@ucas.ac.cn [Theoretical Condensed Matter Physics and Computational Materials Physics Laboratory, School of Physics, University of Chinese Academy of Sciences, Beijing 100049 (China); Zheng, Qing-Rong [Theoretical Condensed Matter Physics and Computational Materials Physics Laboratory, School of Physics, University of Chinese Academy of Sciences, Beijing 100049 (China); Zhu, Zheng-Gang [Theoretical Condensed Matter Physics and Computational Materials Physics Laboratory, School of Physics, University of Chinese Academy of Sciences, Beijing 100049 (China); School of Electronics, Electric and Communication Engineering, University of Chinese Academy of Sciences, Beijing 100049 (China); Su, Gang, E-mail: gsu@ucas.ac.cn [Theoretical Condensed Matter Physics and Computational Materials Physics Laboratory, School of Physics, University of Chinese Academy of Sciences, Beijing 100049 (China)

2015-04-17

The current-induced magnetic switching of a single-molecule magnet (SMM) attached on the central region of a spin valve is explored, and the condition for the switching current is derived. Electrons flowing through the spin valve will interact with the SMM via the s–d exchange interaction, producing the spin accumulation that satisfies the spin diffusion equation. We further describe the spin motion of the SMM by a Heisenberg-like equation. Based on the linear stability analysis, we obtain the critical current from two coupled equations. The results of the critical current versus the external magnetic field indicate that one can manipulate the magnetic state of the SMM by an external magnetic field. - Highlights: • We theoretically study the current-induced magnetic switching of the SMM. • We describe the spin motion of the SMM by a Heisenberg-like equation. • We describe the spin accumulation by the spin diffusion equation. • We obtain the critical current by the linear stability analysis. • Our approach can be easily extended to other SMMs.

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

Science.gov (United States)

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.

Current Account Balance and Export Performances: Evidence Based on New EU Countries

Directory of Open Access Journals (Sweden)

Bogdan Željko

2017-11-01

Full Text Available In this paper, we investigate whether the differences in the current account balance and export performances for a new EU countries are a result of exchange rate policies. The analysis shows that countries with a flexible exchange rate have better export performances and the current account balance in the pre-crisis period. The obtained results show that movements in the current account balance are mainly driven by domestic variables. In the countries with a flexible exchange rate, real and nominal depreciation affects export positively although the magnitude of these effects is tiny and limited to the crisis period. These results point to a higher significance of non-price competitiveness on export which should be a future research topic.

Current and future levels of mercury atmospheric pollution on global scale

NARCIS (Netherlands)

Pacyna, Jozef M.; Travnikov, Oleg; De Simone, Francesco; Hedgecock, Ian M.; Sundseth, Kyrre; Pacyna, Elisabeth G.; Steenhuisen, Frits; Pirrone, Nicola; Munthe, John; Kindbom, Karin

2016-01-01

An assessment of current and future emissions, air concentrations and atmospheric deposition of mercury world-wide are presented on the basis of results obtained during the performance of the EU GMOS (Global Mercury Observation System) project. Emission estimates for mercury were prepared with the

Management of Current Psychiatric Disorders

Science.gov (United States)

Carbonnel, François; David, Michel; Norton, Joanna; Bourrel, Gérard; Boulenger, Jean-Philippe; Capdevielle, Delphine

2016-01-01

Objective: Describe and analyse the experience of family physicians in managing current psychiatric disorders to obtain a better understanding of the underlying reasons of under-detection and inadequate prescribing identified in studies. Methods: A qualitative study using in-depth interviews. Sample of 15 practicing family physicians, recruited by telephone from a precedent cohort (Sesame1) with a maximum variation: sex, age, single or group practice, urban or rural. Qualitative method is inspired by the completed grounded theory of a verbatim semiopragmatic analysis from 2 experts in this approach. Results: Family physicians found that current psychiatric disorders were related to psychological symptoms in reaction to life events. Their role was to make patients aware of a psychiatric symptom rather than establish a diagnosis. Their management responsibility was considered in contrasting ways: it was claimed or endured. They defined their position as facilitating compliance to psychiatrist consultations, while assuring a complementary psychotherapeutic approach. Prescribing medication was not a priority for them. Conclusions: The identified under-detection is essentially due to inherent frontline conditions and complexity of clinical forms. The family physician role, facilitating compliance to psychiatrist consultations while assuring a support psychotherapy is the main result of this study. More studies should be conducted to define more accurately the clinical reality, management and course of current psychiatric disorders in primary care.

Experimental study of neoclassical currents

International Nuclear Information System (INIS)

Zarnstorff, M.C.; Prager, S.C.

1985-05-01

A detailed experimental study is presented of the bootstrap and Pfirsch-Schlueter currents that are predicted by neoclassical transport theory. In a toroidal octupole, on magnetic surfaces within the separatrix, the observed parallel plasma currents are in excellent quantitative agreement with neoclassical theory with regard to the spatial structure (along a magnetic surface), collisionality dependence and toroidal magnetic field dependence. On magnetic surfaces outside the separatrix, the ion portion of the parallel current is in agreement with neoclassical theory but the electron parallel current is observed to obtain a unidirectional component which deviates from and exceeds the theoretical prediction

The effect of solar and lunar currents on simultaneous phase path, group path and amplitude measurements

International Nuclear Information System (INIS)

Baulch, R.N.E.; Butcher, E.C.

1984-01-01

The solar and lunar variations in the phase path, group path and amplitude of a fixed frequency transmission were obtained at the September equinox over a slightly oblique path. The phase of the lunar semi-diurnal tide in the phase path and amplitude were similar, the maxima occurring near 0200 lunar time, whereas the group path had a maximum near 0800 lunar time. These results were compared with other results obtained near the same location. The results suggest a complex situation in the E-region, where the height of the lunar current depends on season, and also suggest that the location and distribution of the solar and lunar currents may be different. (author)

Digital peak current mode control with adaptive slope compensation for DC-DC converters

DEFF Research Database (Denmark)

Andersen, Karsten Holm; Nymand, Morten

2017-01-01

performance and stability of current mode control. The presented method adapt to DC-DC converter operating conditions by estimating the rising and falling inductor current slopes, to apply a current slope compensation value to obtain a constant quality factor. The experimental results verifies the theoretical......This paper presents an adaptive slope compensation method for peak current mode control of digital controlled DC-DC converters, which controls the quality factor of the complex conjugated poles at half the switching frequency. Using quality factor control enables optimization of the dynamic...

Resolving Overlimiting Current Mechanisms in Microchannel-Nanochannel Interface Devices

Science.gov (United States)

Yossifon, Gilad; Leibowitz, Neta; Liel, Uri; Schiffbauer, Jarrod; Park, Sinwook

2015-11-01

We present results demonstrating the space charge-mediated transition between classical, diffusion-limited current and surface-conduction dominant over-limiting currents in a shallow micro-nanochannel device. The extended space charge layer develops at the depleted micro-nanochannel entrance at high current and is correlated with a distinctive maximum in the dc resistance. Experimental results for a shallow surface-conduction dominated system are compared with theoretical models, allowing estimates of the effective surface charge at high voltage to be obtained. Further, we extend the study to microchannels of moderate to large depths where the role of various electro-convection mechanisms becomes dominant. In particular, electro-osmotic of the second kind and electro-osmotic instability (EOI) which competes each other at geometrically heterogeneous (e.g. undulated nanoslot interface, array of nanoslots) nanoslot devices. Also, these effects are also shown to be strongly modulated by the non-ideal permselectivity of the nanochannel.

Bilateral cochlear implantation: current concepts, indications, and results.

Science.gov (United States)

Basura, Gregory J; Eapen, Rose; Buchman, Craig A

2009-12-01

The optimal treatment for bilateral hearing loss continues to evolve as cochlear implant (CI) and hearing aid technologies advance, as does our understanding of the central auditory system. Ongoing discussions continue on the validity and feasibility of bilateral CI in terms of performance, justification of need, medical/surgical safety concerns, and economics. The purpose of this review article is to provide an update on the advantages and disadvantages of bilateral CI and to provide a discussion on timing (simultaneous vs. sequential), technology (bimodal vs. binaural) and feasibility. Binaural advantages are found in both adult and pediatric bilateral CI recipients, the greatest being the head shadow effect and improvements in localization and loudness summation. This theoretically offers an advantage over their unilateral implanted counterparts in terms of improved sound localization and enhanced speech perception under noisy conditions. Most investigators agree that bilateral stimulation during critical periods of development is paramount for optimizing auditory functioning in children. Currently, bilateral CI is widely accepted as a safe and effective means of bilateral auditory stimulation.

Anomalous current in periodic Lorentz gases with infinite horizon

Energy Technology Data Exchange (ETDEWEB)

Dolgopyat, Dmitrii I [University of Maryland, College Park (United States); Chernov, Nikolai I [University of Alabama at Birmingham, Birmingham, Alabama (United States)

2009-08-31

Electric current is studied in a two-dimensional periodic Lorentz gas in the presence of a weak homogeneous electric field. When the horizon is finite, that is, free flights between collisions are bounded, the resulting current J is proportional to the voltage difference E, that is, J=1/2 D*E+o(||E||), where D* is the diffusion matrix of a Lorentz particle moving freely without an electric field (see a mathematical proof). This formula agrees with Ohm's classical law and the Einstein relation. Here the more difficult model with an infinite horizon is investigated. It is found that infinite corridors between scatterers allow the particles (electrons) to move faster, resulting in an abnormal current (causing 'superconductivity'). More precisely, the current is now given by J=1/2 DE| log||E|| | + O(||E||), where D is the 'superdiffusion' matrix of a Lorentz particle moving freely without an electric field. This means that Ohm's law fails in this regime, but the Einstein relation (suitably interpreted) still holds. New results are also obtained for the infinite-horizon Lorentz gas without external fields, complementing recent studies by Szasz and Varju. Bibliography: 31 titles.

Anomalous current in periodic Lorentz gases with infinite horizon

International Nuclear Information System (INIS)

Dolgopyat, Dmitrii I; Chernov, Nikolai I

2009-01-01

Electric current is studied in a two-dimensional periodic Lorentz gas in the presence of a weak homogeneous electric field. When the horizon is finite, that is, free flights between collisions are bounded, the resulting current J is proportional to the voltage difference E, that is, J=1/2 D*E+o(||E||), where D* is the diffusion matrix of a Lorentz particle moving freely without an electric field (see a mathematical proof). This formula agrees with Ohm's classical law and the Einstein relation. Here the more difficult model with an infinite horizon is investigated. It is found that infinite corridors between scatterers allow the particles (electrons) to move faster, resulting in an abnormal current (causing 'superconductivity'). More precisely, the current is now given by J=1/2 DE| log||E|| | + O(||E||), where D is the 'superdiffusion' matrix of a Lorentz particle moving freely without an electric field. This means that Ohm's law fails in this regime, but the Einstein relation (suitably interpreted) still holds. New results are also obtained for the infinite-horizon Lorentz gas without external fields, complementing recent studies by Szasz and Varju. Bibliography: 31 titles.

Holographic heat current as Noether current

Science.gov (United States)

Liu, Hai-Shan; Lü, H.; Pope, C. N.

2017-09-01

We employ the Noether procedure to derive a general formula for the radially conserved heat current in AdS planar black holes with certain transverse and traceless perturbations, for a general class of gravity theories. For Einstein gravity, the general higher-order Lovelock gravities and also a class of Horndeski gravities, we derive the boundary stress tensor and show that the resulting boundary heat current matches precisely the bulk Noether current.

Comparison of visual field test results obtained through Humphrey matrix frequency doubling technology perimetry versus standard automated perimetry in healthy children

Directory of Open Access Journals (Sweden)

Sibel Kocabeyoglu

2013-01-01

Full Text Available Aims : The aim of this study was to compare the visual field test results in healthy children obtained via the Humphrey matrix 24-2 threshold program and standard automated perimetry (SAP using the Swedish interactive threshold algorithm (SITA-Standard 24-2 test. Materials and Methods: This prospective study included 55 healthy children without ocular or systemic disorders who underwent both SAP and frequency doubling technology (FDT perimetry visual field testing. Visual field test reliability indices, test duration, global indices (mean deviation [MD], and pattern standard deviation [PSD] were compared between the 2 tests using the Wilcoxon signed-rank test and paired t-test. The performance of the Humphrey field analyzer (HFA 24-2 SITA-standard and frequency-doubling technology Matrix 24-2 tests between genders were compared with Mann-Whitney U-test. Results: Fifty-five healthy children with a mean age of 12.2 ± 1.9 years (range from 8 years to 16 years were included in this prospective study. The test durations of SAP and FDT were similar (5.2 ± 0.5 and 5.1 ± 0.2 min, respectively, P = 0.651. MD and the PSD values obtained via FDT Matrix were significantly higher than those obtained via SAP (P < 0.001, and fixation losses and false negative errors were significantly less with SAP (P < 0.05. A weak positive correlation between the two tests in terms of MD (r = 0.352, P = 0.008 and PSD (r = 0.329, P = 0.014 was observed. Conclusion: Children were able to complete both the visual test algorithms successfully within 6 min. However, SAP testing appears to be associated with less depression of the visual field indices of healthy children. FDT Matrix and SAP should not be used interchangeably in the follow-up of children.

The similia principle: results obtained in a cellular model system.

Science.gov (United States)

Wiegant, Fred; Van Wijk, Roeland

2010-01-01

This paper describes the results of a research program focused on the beneficial effect of low dose stress conditions that were applied according to the similia principle to cells previously disturbed by more severe stress conditions. In first instance, we discuss criteria for research on the similia principle at the cellular level. Then, the homologous ('isopathic') approach is reviewed, in which the initial (high dose) stress used to disturb cellular physiology and the subsequent (low dose) stress are identical. Beneficial effects of low dose stress are described in terms of increased cellular survival capacity and at the molecular level as an increase in the synthesis of heat shock proteins (hsps). Both phenomena reflect a stimulation of the endogenous cellular self-recovery capacity. Low dose stress conditions applied in a homologous approach stimulate the synthesis of hsps and enhance survival in comparison with stressed cells that were incubated in the absence of low dose stress conditions. Thirdly, the specificity of the low dose stress condition is described where the initial (high dose) stress is different in nature from the subsequently applied (low dose) stress; the heterologous or 'heteropathic' approach. The results support the similia principle at the cellular level and add to understanding of how low dose stress conditions influence the regulatory processes underlying self-recovery. In addition, the phenomenon of 'symptom aggravation' which is also observed at the cellular level, is discussed in the context of self-recovery. Finally, the difference in efficiency between the homologous and the heterologous approach is discussed; a perspective is indicated for further research; and the relationship between studies on the similia principle and the recently introduced concept of 'postconditioning hormesis' is emphasized. Copyright 2009 The Faculty of Homeopathy. Published by Elsevier Ltd. All rights reserved.

Preliminary determination of the energy potential of ocean currents along the southern coast of Brazil

Energy Technology Data Exchange (ETDEWEB)

Fischer, Andrea; Beluco, Alexandre; de Almeida, Luiz Emilio B. [Inst. Pesquisas Hidraulicas, Univ. Fed Rio Grande do Sul, Porto Alegre (Brazil)

2013-07-01

The ocean can be a strategic alternative for obtaining energy supplies, both from ocean waves as from sea currents and tides. Among these features, the power generation projects based on ocean currents are still under development. Generating energy from ocean can have great impact on the Brazilian energy grid, since Brazil has a vast coastline, with more than 9,000 km long, with potential for generating energy from ocean currents not fully estimated. This article presents a preliminary determination of the energy potential for power generation from ocean currents along the coast of Rio Grande do Sul, the southernmost state of Brazil, and also presents notes that contribute to the characterization of the system of ocean currents in the region. The data used were obtained in two areas near Tramandai, allowing the determination of velocities and directions of the currents on a seasonal basis. The maximum speeds obtained rarely exceed 0.750 m/s, while the average speeds do not exceed 0.200 m/s. A relationship with the prevailing winds in the region was identified. Unfortunately, the results do not allow optimism about the power generation from ocean currents on the southern coast of Brazil, at least over the continental shelf.

Eddy current detection of spacers in the fuel channels of CANDU nuclear reactors

International Nuclear Information System (INIS)

Krause, T.W.; Schankula, J.; Sullivan, S.P.

2002-01-01

Garter Spring (GS) spacers in the fuel channels of CANDU nuclear reactors maintain separation between the hot pressure tube and surrounding moderator cooled calandria tube. Eddy current detection of the four GSs provides assurance that spacers are at or close to design positions and are performing their intended function of maintaining a non-zero gap between pressure tube and calandria tube. Pressure tube constrictions, resulting from relatively less diametral creep at end-of-fuel bundle locations, also produce large eddy current signals. Large constrictions, present in higher service pressure tubes, can produce signals that are 10 times larger than GS signals, reducing GS detectability to 30% in standard GS-detect probes. The introduction of field-focussing elements into the design of the standard GS detection eddy current probe has been used to recover the detectability of GS spacers by increasing the signal amplitude obtained from GSs relative to that from constrictions by a factor of 10. The work presented here compares laboratory, modelling and in-reactor measurements of GS and constriction signals obtained from the standard probe with that obtained from field-focussed eddy current probe designs. (author)

Current saturation in tellurium caused by the acoustoelectric effect at 4.2 K

International Nuclear Information System (INIS)

Bondar, V.M.; Radchenko, V.S.

1980-01-01

Current voltage characteristics of p-Te for x- and z-cuts have been taken for different time moments and at an electric field pulse with nonosecond duration at 77 and 4.2 K (incubation time). Experimental and calculational field dependences of incubation time of ac- aoustic electrical current for xnd z-cut in p-Te in 77-4.2 K temperature range have been obtained. Satisfactory (and unusual at 4.2 K) coincidence of experimental and calculational curves justifies aplication of the incubation time approximation. The results obtained allow to support an assumption of strengthening of extraaxial modes by ''supersonic'' carriers drifting along the C 3 axis. Obtained are experimental data permitting to eliminate the acoustic electric effect in studies of mechanisms of carrier scattering in Te by choosing the proper duration of field pulses

Analytical study on discrete model of virtual cathode in a high-current diode

International Nuclear Information System (INIS)

Privezentsev, A.P.

1988-01-01

Interest in investigation of virtual cathode dynamics related to the development of high-current accelerator equipment is caused by the possibility of its application for ion collective acceleration in direct high-current electron beams and generation of power electromagnetic radiation. The Hamiltonian form of a plane sheet model for a high-current flux in a plane diode is investigated. Variables used permit to carry out the investigation of dynamics of the virtual cathode flux by the method of coordinate point transformations in a phase space. The necessity of numerical integration of sheet motion equations is dropped out in this case. Analytical solution of the suggested iterative circuit for total flux passage is presented as an example. The solution obtained is equivalent to the known results of the plane diode theory, obtained in the hydrodynamic approximation

Experiments for obtaining field influence mass particles.

CERN Document Server

Yahalomi, E

2010-01-01

Analyzing time dilation experiments the existence of a universal field interacting with moving mass particles is obtained. It is found that mass particle changes its properties depend on its velocity relative to this universal scalar field and not on its velocity relative to the laboratory. High energy proton momentum, energy and mass were calculated obtaining new results. Experiments in high energy accelerators are suggested as additional proofs for the existence of this universal field. This universal field may explain some results of other high energy experiments.

Automatic J–A Model Parameter Tuning Algorithm for High Accuracy Inrush Current Simulation

Directory of Open Access Journals (Sweden)

Xishan Wen

2017-04-01

Full Text Available Inrush current simulation plays an important role in many tasks of the power system, such as power transformer protection. However, the accuracy of the inrush current simulation can hardly be ensured. In this paper, a Jiles–Atherton (J–A theory based model is proposed to simulate the inrush current of power transformers. The characteristics of the inrush current curve are analyzed and results show that the entire inrush current curve can be well featured by the crest value of the first two cycles. With comprehensive consideration of both of the features of the inrush current curve and the J–A parameters, an automatic J–A parameter estimation algorithm is proposed. The proposed algorithm can obtain more reasonable J–A parameters, which improve the accuracy of simulation. Experimental results have verified the efficiency of the proposed algorithm.

Determining the Limiting Current Density of Vanadium Redox Flow Batteries

Directory of Open Access Journals (Sweden)

Jen-Yu Chen

2014-09-01

Full Text Available All-vanadium redox flow batteries (VRFBs are used as energy storage systems for intermittent renewable power sources. The performance of VRFBs depends on materials of key components and operating conditions, such as current density, electrolyte flow rate and electrolyte composition. Mass transfer overpotential is affected by the electrolyte flow rate and electrolyte composition, which is related to the limiting current density. In order to investigate the effect of operating conditions on mass transport overpotential, this study established a relationship between the limiting current density and operating conditions. First, electrolyte solutions with different states of charge were prepared and used for a single cell to obtain discharging polarization curves under various operating conditions. The experimental results were then analyzed and are discussed in this paper. Finally, this paper proposes a limiting current density as a function of operating conditions. The result helps predict the effect of operating condition on the cell performance in a mathematical model.

Current distribution in conducting nanowire networks

Science.gov (United States)

Kumar, Ankush; Vidhyadhiraja, N. S.; Kulkarni, Giridhar U.

2017-07-01

Conducting nanowire networks find diverse applications in solar cells, touch-screens, transparent heaters, sensors, and various related transparent conducting electrode (TCE) devices. The performances of these devices depend on effective resistance, transmittance, and local current distribution in these networks. Although, there have been rigorous studies addressing resistance and transmittance in TCE, not much attention is paid on studying the distribution of current. Present work addresses this compelling issue of understanding current distribution in TCE networks using analytical as well as Monte-Carlo approaches. We quantified the current carrying backbone region against isolated and dangling regions as a function of wire density (ranging from percolation threshold to many multiples of threshold) and compared the wired connectivity with those obtained from template-based methods. Further, the current distribution in the obtained backbone is studied using Kirchhoff's law, which reveals that a significant fraction of the backbone (which is believed to be an active current component) may not be active for end-to-end current transport due to the formation of intervening circular loops. The study shows that conducting wire based networks possess hot spots (extremely high current carrying regions) which can be potential sources of failure. The fraction of these hot spots is found to decrease with increase in wire density, while they are completely absent in template based networks. Thus, the present work discusses unexplored issues related to current distribution in conducting networks, which are necessary to choose the optimum network for best TCE applications.

Correlation of eddy current responses between fatigue cracks and electrical-discharge-machining notches

Science.gov (United States)

Seo, Sukho; Choi, Gyudong; Eom, Tae Jhoun; Lee, Bokwon; Lee, Soo Yeol

2017-07-01

The eddy current responses of Electrical Discharge Machining (EDM) notches and fatigue cracks are directly compared to verify the reliability of eddy current inspection. The fatigue crack growth tests using a constant load range control mode were conducted to obtain a variety of edge crack sizes, ranging from 0.9 to 6.6 mm for Al alloy and from 0.1 to 3 mm for Ti alloy. EDM notch specimens of Al and Ti alloys were accordingly prepared in lengths similar to that of the fatigued specimen. The crack length was determined by optical microscope and scanning electron microscope. The eddy current responses between the EDM and fatigued specimens with varying notch/crack length were examined using probe sensors at (100-500) kHz and (1-2) MHz for Al and Ti alloys, respectively. The results show a significant difference in the eddy current signal between the two specimens, based on the correlation between the eddy current response and notch/crack length. This suggests that eddy current inspection using the EDM reference specimen is inaccurate in determining the precise crack size, unless the eddy current response data base is obtained from a fatigue-cracked specimen.

Analysis of results obtained with different cutting techniques and associated filtration systems for the dismantling of radioactive metallic components

International Nuclear Information System (INIS)

Bach, F.W.; Steiner, H.; Schreck, G.

1993-01-01

The present joint study performed by the Commissariat a l'energie atomique and the Universitaet Hannover and coordinated by the Commission of the European Communities was intended to analyse the results generated in a number of research contracts concerned with cutting tests in air and underwater, with consideration of the prevailing working conditions. The analysis has led to a large database, giving broadly-assessed information for the dismantling of radioactive components. The range of study was enlarged, where possible, to include recently obtained results outside the present research programme, consideration also being given to supplementary cutting tools and filtration systems not covered by the present programme. Data was concentrated in structured information packages on practical experience available for a series of cutting tools and filters. These were introduced into a computerized user-friendly databank, to be considered as a first-stage development, which should be continuously updated and possibly oriented in the future to an expert system

Review of the scientific results obtained at the research reactor-booster IBR-30 and the Program of investigations at the neutron source IREN

CERN Document Server

Furman, W

2002-01-01

Brief review of the main scientific results obtained at research reactor booster IBR-30 and its predecessor IBR and IBR-1 for the period 1960 - 2001 is presented. The thesis of the scientific program for the upgrade of IBR-30 resonance neutron source IREN are adduced

LIGNOCELLULOSE AS AN ALTERNATIVE SOURCE FOR OBTAINING OF BIOBUTANOL

Directory of Open Access Journals (Sweden)

S. M. Shulga

2013-04-01

Full Text Available Energy and environmental crisis facing the world force us to reconsider the effectiveness or find an alternative use of renewable natural resources, especially organic «waste» by using environmentally friendly technologies. Microbial conversion of renewable resources of biosphere to produce useful products, including biofuels, currently is an actual biotech problem. Anaerobic bacteria of Clostridiaceae family are known as butanol producers, but unfortunately, the microbiological synthesis is currently not economical one. In order to make cost-effective aceton-butanol-ethanol fermentation, solventproducing strains using available cheap raw materials, such as agricultural waste or plant biomass, are required. Opportunities and ways to obtaine economic and ecological processing of lignocellulosic wastes for biobutanol creation are described in the review .

EDDYTRAN program system for eddy current, electromagnetic force and structural analysis

International Nuclear Information System (INIS)

Kameari, A.; Nikura, S.

1983-01-01

A computer program system (EDDYTRAN), which is applicable to torus structures of magnetic fusion devices, has been developed to calculate the eddy current, electromagnetic force and structural analysis. The program system is designed to perform the following functions sequentially: 1) generation of model mesh and other data such as electromagnetic and mechanical properties of finite elements and boundary conditions, 2) calculations of eddy currents and electromagnetic forces, 3) transformation of the resultant force to load data fit to the structural analysis program, 4) structural analysis and 5) post-processing of the results. The EDDYTRAN utilizes the EDDYCUFF (EDDY CUrrent, magnetic Field and electromagnetic Force) program and the NASTRAN (NASA STRuctural ANalysis) program. Here, the EDDYCUFF program which has been developed by the authors is a generalized computer program to calculate transient eddy currents, resultant magnetic fields and electromagnetic forces in the conductive components. This paper describes the outline of the EDDYTRAN program system and preliminary results obtained through the application to the Tokamak reactor design which was performed for the Japan Atomic Energy Research Institute

Plasma characteristics in the discharge region of a 20 A emission current hollow cathode

Science.gov (United States)

Mingming, SUN; Tianping, ZHANG; Xiaodong, WEN; Weilong, GUO; Jiayao, SONG

2018-02-01

Numerical calculation and fluid simulation methods were used to obtain the plasma characteristics in the discharge region of the LIPS-300 ion thruster’s 20 A emission current hollow cathode and to verify the structural design of the emitter. The results of the two methods indicated that the highest plasma density and electron temperature, which improved significantly in the orifice region, were located in the discharge region of the hollow cathode. The magnitude of plasma density was about 1021 m-3 in the emitter and orifice regions, as obtained by numerical calculations, but decreased exponentially in the plume region with the distance from the orifice exit. Meanwhile, compared to the emitter region, the electron temperature and current improved by about 36% in the orifice region. The hollow cathode performance test results were in good agreement with the numerical calculation results, which proved that that the structural design of the emitter and the orifice met the requirements of a 20 A emission current. The numerical calculation method can be used to estimate plasma characteristics in the preliminary design stage of hollow cathodes.

Determination of residual stresses in steel 20 comparison of the results obtained by the Barkhausen noise and X-ray diffraction

International Nuclear Information System (INIS)

Fernandez, L. M.; Herrera, V.; Suarez, J.C.; Merino, F.J.

1997-01-01

During a heat treatment (quenching, surface hardening, Thermochemical treatment) the metallic alloys undergo temperature variations and phase transformation. The resulting changes give rise to internal stresses in the piece. Phase transformation modifies the thermomechanical behavior of the material through the change of mechanical properties ( hardness, fatigue-behaviour, corrosion resistance, electric resistivity, etc.) The aim of this paper is residual stress measurements in specimens of steel-20 submitted to different heat treatment, by two non destructive methods: Barkhausen and X-ray diffraction. Brakhausen Effects utilizes the magnetic properties of ferromagnetic materials such as ferritic and perlitic steels and provides a practical tool for surface streets evaluation. X-ray streets analysis is based on the measurement of lattice strains in different directions of specimen The results obtained by two techniques are compared, avowing a good agreement

INVESTIGATION OF PROPERTIES OF CURRENT COLLECTOR ELEMENTS AND THEIR EFFECT ON THE PERFORMANCE OF TRIBOSYSTEM «CONTACT WIRE - CURRENT COLLECTOR ELEMENT»

Directory of Open Access Journals (Sweden)

Yu. L. Bolshakov

2015-11-01

Full Text Available Purpose. The paper is devoted to the detailed analysis of interrelations at the contact point of friction pair «contact wire – current collector insert». In the work it is necessary: 1 to examine quality of manufacturing of specimens of current collector elements from different manufacturers; 2 to narrow the range of hardness for carbon inserts; 3 to develop a technique of sorting carbon current collector inserts for the structural parameters. Methodology. The executed work was based on the use of the theory of reliability of technical systems and electromechanical processes. Findings. The paper studies the interrelation at the contact point of friction pair «contact wire – current col lector insert», the connection was established between the hardness and electrical resistivity. It is proposed to narrow the range of carbon inserts hardness. The method of sorting coal collector inserts in hardness was developed, and the research has revealed the discrepancy of current collector inserts with existing regulations. It was proposed to equip the pantographs slide with current collector elements using special scheme and to develop a specialized research facility, which will be possible to conduct studies of the interaction of the friction pair «contact wire – current collector insert». Originality. In the course of the study the current collector inserts the sharp structural heterogeneity and fluctuations of the density of the material along the length of the insert were established. The dependence between hardness of inserts and electrical resistivity was established. It was analyzed and concluded about the need to reduce the values of the normal range of hardness. Based on the results of the research, the experimental dependences were obtained and proposed the method for sorting carbon current collector inserts for the structural parameters. Practical value. The obtained results of coal current collector inserts define the need to use

Bow Shock Generator Current Systems: MMS Observations of Possible Current Closure

Science.gov (United States)

Hamrin, M.; Gunell, H.; Lindkvist, J.; Lindqvist, P.-A.; Ergun, R. E.; Giles, B. L.

2018-01-01

We use data from the first two dayside seasons of the Magnetospheric Multiscale (MMS) mission to study current systems associated with quasi-perpendicular bow shocks of generator type. We have analyzed 154 MMS bow shock crossings near the equatorial plane. We compute the current density during the crossings and conclude that the component perpendicular to the shock normal (J⊥) is consistent with a pileup of the interplanetary magnetic field (IMF) inside the magnetosheath. For predominantly southward IMF, we observe a component Jn parallel (antiparallel) to the normal for GSM Y > 0 (MMS probing region. For IMF clock angles near 90∘, we find indications of the current system being tilted toward the north-south direction, obtaining a significant Jz component, and we suggest that the current closes off the equatorial plane at higher latitudes where the spacecraft are not probing. The observations are complicated for several reasons. For example, variations in the solar wind and the magnetospheric currents and loads affect the closure, and Jn is distributed over large regions, making it difficult to resolve inside the magnetosheath proper.

Superconducting fault current limiter using high-resistive YBCO tapes

Energy Technology Data Exchange (ETDEWEB)

Yazawa, T. [Power and Industrial System R and D Center, Toshiba Corporation, 2-4 Suehiro, Tsurumi, Yokohama 230-0045 (Japan)], E-mail: takashi.yazawa@toshiba.co.jp; Koyanagi, K.; Takahashi, M.; Ono, M.; Toba, K.; Takigami, H.; Urata, M. [Power and Industrial System R and D Center, Toshiba Corporation, 2-4 Suehiro, Tsurumi, Yokohama 230-0045 (Japan); Iijima, Y.; Saito, T. [Fujikura Ltd., 1-5-1 Kiba, Koto, Tokyo 135-0042 (Japan); Ameniya, N. [Yokohama National University, 79-1 Tokiwadai, Hodogaya, Yokohama 240-8501 (Japan); Shiohara, Y. [Superconductivity Research Laboratory, ISTEC, 1-10-13 Shinonome, Koto, Tokyo 135-0062 (Japan)

2008-09-15

One of the programs in the Ministry of Economy and Trade and Industry (METI) project regarding R and D on YBCO conductor is to evaluate the applicability of the developed conductor toward several applications. This paper focuses on a fault current limiter (FCL) as one of the expected power applications. YBCO tape conductors with ion beam assisted deposition (IBAD) substrate are used in this work. In order to obtain high resistance of the conductor, which is preferable to an FCL, the thickness of the protecting layer made of silver was decreased as possible. Then high-resistive metal stabilizing layer is attached on the silver layer to improve stability. Obtaining the relevant current limiting performance on short sample experiments, model coils were developed to aim the 6.6 kV-class FCL. Short circuit experiments were implemented with a short circuit generator. The coil successfully restricted the short circuit current over 17 kA to about 700 A by the applied voltage of 3.8 kV, which is nominal phase-to-ground voltage. The experimental results show good agreement with computer analyses and show promising toward the application.

High current DC negative ion source for cyclotron

Energy Technology Data Exchange (ETDEWEB)

Etoh, H., E-mail: Hrh-Etoh@shi.co.jp; Aoki, Y.; Mitsubori, H.; Arakawa, Y.; Sakuraba, J.; Kato, T.; Mitsumoto, T.; Hiasa, T.; Yajima, S. [Sumitomo Heavy Industries, Ltd., Tokyo 141-6025 (Japan); Onai, M.; Hatayama, A. [Graduate School of Science and Technology, Keio University, Kanagawa 223-8522 (Japan); Shibata, T. [High Energy Accelerator Research Organization (KEK), Ibaraki 305-0801 (Japan); Okumura, Y. [Fusion Research and Development Directorate, Japan Atomic Energy Agency, Aomori 039-3212 (Japan)

2016-02-15

A filament driven multi-cusp negative ion source has been developed for proton cyclotrons in medical applications. In Cs-free operation, continuous H{sup −} beam of 10 mA and D{sup −} beam of 3.3 mA were obtained stably at an arc-discharge power of 3 kW and 2.4 kW, respectively. In Cs-seeded operation, H{sup −} beam current reached 22 mA at a lower arc power of 2.6 kW with less co-extracted electron current. The optimum gas flow rate, which gives the highest H{sup −} current, was 15 sccm in the Cs-free operation, while it decreased to 4 sccm in the Cs-seeded operation. The relationship between H{sup −} production and the design/operating parameters has been also investigated by a numerical study with KEIO-MARC code, which gives a reasonable explanation to the experimental results of the H{sup −} current dependence on the arc power.

Experiments of full non-inductive current drive on HT-7

International Nuclear Information System (INIS)

Zhang, X.D.; Wu, Z.W.; Chen, Z.Y.; Gong, X.Z.; Wang, H.; Xu, D.; Huang, Y.; Luo, J.; Gao, X.; Hu, L.; Zhao, J.; Wan, B.N.; Li, J.

2005-01-01

Some experimental results of steady-state operation and full non-inductive current drive have been obtained on HT-7. Three types of experiment are used to study long pulse discharge, quasi-steady-state operation and full non-inductive current drive. The experiments show that the plasma current in the full non-inductive drive case is instable due to no adjusting effect of OH heating field, when the waveguide tube discharge lead to the LHW power injecting tokamak plasma decrease. This instability of plasma current will increase the interaction of plasma with limiter and first surface and bring impurity. All discharges of full non-inductive current drive are terminated because of impurity spurting. To adjust the LHW injection power for control the loop voltage during long pulse discharge is the most effective method for steady-state operation on HT-7. (author)

Current and future levels of mercury atmospheric pollution on a global scale

NARCIS (Netherlands)

Pacyna, J. M.; Travnikov, O.; De Simone, F.; Hedgecock, I. M.; Sundseth, K.; Pacyna, E. G.; Steenhuisen, F.; Pirrone, N.; Munthe, J.; Kindbom, K.

2016-01-01

An assessment of current and future emissions, air concentrations, and atmospheric deposition of mercury worldwide is presented on the basis of results obtained during the performance of the EU GMOS (Global Mercury Observation System) project. Emission estimates for mercury were prepared with the

Process for obtaining cobalt and lanthanum nickelate

International Nuclear Information System (INIS)

Tapcov, V.; Samusi, N.; Gulea, A.; Horosun, I.; Stasiuc, V.; Petrenco, P.

1999-01-01

The invention relates to the process for obtaining polycrystalline ceramics of cobalt and lanthanum nickelate with the perovskite structure from coordinative hetero metallic compounds. The obtained products can be utilized in the industry in the capacity of catalysts. Summary of the invention consists in obtaining polycrystalline ceramics LaCoO 3 and LaNiO 3 with the perovskite structure by pyrolysis of the parent compounds, namely, the coordinative hetero metallic compounds of the lanthanum cobalt or lanthanum nickel. The pyrolysis of the parent compound runs during one hour at 800 C. The technical result of the invention consists in lowering the temperature of the parent compound pyrolysis containing the precise ratio of metals necessary for ceramics obtaining

Coastal tomographic mapping of nonlinear tidal currents and residual currents

Science.gov (United States)

Zhu, Ze-Nan; Zhu, Xiao-Hua; Guo, Xinyu

2017-07-01

Depth-averaged current data, which were obtained by coastal acoustic tomography (CAT) July 12-13, 2009 in Zhitouyang Bay on the western side of the East China Sea, are used to estimate the semidiurnal tidal current (M2) as well as its first two overtide currents (M4 and M6). Spatial mean amplitude ratios M2:M4:M6 in the bay are 1.00:0.15:0.11. The shallow-water equations are used to analyze the generation mechanisms of M4 and M6. In the deep area, where water depths are larger than 60 m, M4 velocity amplitudes measured by CAT agree well with those predicted by the advection terms in the shallow water equations, indicating that M4 in the deep area is predominantly generated by the advection terms. M6 measured by CAT and M6 predicted by the nonlinear quadratic bottom friction terms agree well in the area where water depths are less than 20 m, indicating that friction mechanisms are predominant for generating M6 in the shallow area. In addition, dynamic analysis of the residual currents using the tidally averaged momentum equation shows that spatial mean values of the horizontal pressure gradient due to residual sea level and of the advection of residual currents together contribute about 75% of the spatial mean values of the advection by the tidal currents, indicating that residual currents in this bay are induced mainly by the nonlinear effects of tidal currents. This is the first ever nonlinear tidal current study by CAT.

Effect of current density and pH in obtaining the Ni-Fe alloy by electrodeposition; Efeito da densidade de corrente e pH na obtencao da liga Ni-Fe por eletrodeposicao

Energy Technology Data Exchange (ETDEWEB)

Oliveira, Jose Anderson Machado; Raulino, Anamelia de Medeiros Dantas; Raulino, Jose Leonardo Costa; Campos, Ana Regina Nascimento; Prasad, Shiva; Santana, Renato Alexandre Costa de, E-mail: jmo.anderson@gmail.com, E-mail: anameliadantas@yahoo.com.br, E-mail: leonardo.jcr@hotmail.com, E-mail: arncampos@yahoo.com.br, E-mail: prasad@deq.ufcg.edu.br, E-mail: renatoacs@ufcg.edu.br [Universidade Federal de Campina Grande (UFCG), Cuite, PB (Brazil). Lab. de Eletroquimica e Corrosao

2017-01-15

Metallic coatings can be applied for different purposes, for example to improve the mechanical, catalytic, anti corrosive properties or simply to improve the decorative appearance. In the work the Fe-Ni alloys have been obtained by electrodeposition process using a simple electrolytic bath containing the reagents, nickel sulfate, iron sulfate and sodium tartrate. A complete experimental design 2{sup 2} , associated with the response surface methodology (RSM) technique was used as optimization tool. Chemical composition, current efficiency, surface morphology and electrochemical corrosion measures were performed. It was observed that a decrease in the pH favored an increase in iron and decrease in nickel contents in the alloy. The iron content influenced the alloy morphology. The best experiment showed an average corrosion resistance 5471.5 Ω.cm² and a corrosion current density 4.814x10{sup -6} A/cm². This experiment presented a composition of 70 wt% Ni and 30 wt% Fe in the alloy and an average deposition current efficiency of 58.7%. (author)

Resistive Instabilities in Hall Current Plasma Discharge

International Nuclear Information System (INIS)

Litvak, Andrei A.; Fisch, Nathaniel J.

2000-01-01

Plasma perturbations in the acceleration channel of a Hall thruster are found to be unstable in the presence of collisions. Both electrostatic lower-hybrid waves and electromagnetic Alfven waves transverse to the applied electric and magnetic field are found to be unstable due to collisions in the E X B electron flow. These results are obtained assuming a two-fluid hydrodynamic model in slab geometry. The characteristic frequencies of these modes are consistent with experimental observations in Hall current plasma thrusters

A general scheme for obtaining graviton spectrums

International Nuclear Information System (INIS)

GarcIa-Cuadrado, G

2006-01-01

The aim of this contribution is to present a general scheme for obtaining graviton spectra from modified gravity theories, based on a theory developed by Grishchuk in the mid 1970s. We try to be pedagogical, putting in order some basic ideas in a compact procedure and also giving a review of the current trends in this arena. With the aim to fill a gap for the interface between quantum field theorists and observational cosmologist in this matter, we highlight two interesting applications to cosmology: clues as to the nature of dark energy; and the possibility of reconstruction of the scalar potential in scalar-tensor gravity theories

Conversion of spin current into charge current in a topological insulator: Role of the interface

Science.gov (United States)

Dey, Rik; Prasad, Nitin; Register, Leonard F.; Banerjee, Sanjay K.

2018-05-01

Three-dimensional spin current density injected onto the surface of a topological insulator (TI) produces a two-dimensional charge current density on the surface of the TI, which is the so-called inverse Edelstein effect (IEE). The ratio of the surface charge current density on the TI to the spin current density injected across the interface defined as the IEE length was shown to be exactly equal to the mean free path in the TI determined to be independent of the electron transmission rate across the interface [Phys. Rev. B 94, 184423 (2016), 10.1103/PhysRevB.94.184423]. However, we find that the transmission rate across the interface gives a nonzero contribution to the transport relaxation rate in the TI as well as to the effective IEE relaxation rate (over and above any surface hybridization effects), and the IEE length is always less than the original mean free path in the TI without the interface. We show that both the IEE relaxation time and the transport relaxation time in the TI are modified by the interface transmission time. The correction becomes significant when the transmission time across the interface becomes comparable to or less than the original momentum scattering time in the TI. This correction is similar to experimental results in Rashba electron systems in which the IEE relaxation time was found shorter in the case of direct interface with metal in which the interface transmission rate will be much higher, compared to interfaces incorporating insulating oxides. Our results indicate the continued importance of the interface to obtain a better spin-to-charge current conversion and a limitation to the conversion efficiency due to the quality of the interface.

Influence of coupling parameter on current-voltage characteristics of intrinsic Josephson junctions in high-T c superconductors

International Nuclear Information System (INIS)

Shukrinov, Yu.M.; Mahfouzi, F.

2006-01-01

We study the current-voltage characteristics of intrinsic Josephson junctions in high-T c superconductors by numerical calculations and in framework of capacitively coupled Josephson junctions model we obtain the total number of branches. The influence of the coupling parameter α on the current-voltage characteristics at fixed parameter β (β 2 1/β c , where β c is McCumber parameter) and the influence of α on β-dependence of the current-voltage characteristics are investigated. We obtain the α-dependence of the branch's slopes and branch's endpoints. The presented results show new features of the coupling effect on the scheme of hysteresis jumps in current-voltage characteristics of intrinsic Josephson junctions in high-T c superconductors

Determination of the inter- and intra-granular critical currents in superconducting YBa2Cu3O7 welds

International Nuclear Information System (INIS)

Bozzo, B; Iliescu, S; Bartolome, E; Palau, A; Granados, X; Puig, T; Obradors, X; Amoros, J; Carrera, M

2005-01-01

A method for determining simultaneously the inter- and intra-grain critical currents has been developed in welded YBa 2 Cu 3 O 7 (YBCO) ceramics by solving the Inverse Problem for local maps of the magnetic field in the remanent state. From that current distribution, the current density flowing through the superconducting weld as well as the current density circulating inside the grains can be deduced. The method is discussed and it is applied to several examples of YBCO/Ag/YBCO welds. The results obtained show that it is possible to obtain superconducting joints with a quality at the same level as that of the starting material

U-Mo Alloy Powder Obtained Through Selective Hydriding. Particle Size Control

International Nuclear Information System (INIS)

Balart, S.N.; Bruzzoni, P.; Granovsky, M.S.

2002-01-01

Hydride-dehydride methods to obtain U-Mo alloy powder for high-density fuel elements have been successfully tested by different authors. One of these methods is the selective hydriding of the α phase (HSα). In the HSα method, a key step is the partial decomposition of the γ phase (retained by quenching) to α phase and an enriched γ phase or U 2 Mo. This transformation starts mainly at grain boundaries. Subsequent hydrogenation of this material leads to selective hydriding of the α phase, embrittlement and intergranular fracture. According to this picture, the particle size of the final product should be related to the γ grain size of the starting alloy. The feasibility of controlling the particle size of the product by changing the γ grain size of the starting alloy is currently investigated. In this work an U-7 wt% Mo alloy was subjected to various heat treatments in order to obtain different grain sizes. The results on the powder particle size distribution after applying the HSα method to these samples show that there is a strong correlation between the original γ grain size and the particle size distribution of the powder. (author)

Polycarbonate-based ordered arrays of electrochemical nanoelectrodes obtained by e-beam lithography

Energy Technology Data Exchange (ETDEWEB)

Moretto, L M; De Leo, M; Ugo, P [Department of Molecular Sciences and Nanosystems, University Ca' Foscari of Venice, Santa Marta 2137, 30123 Venice (Italy); Tormen, M; Carpentiero, A, E-mail: ugo@unive.it [CNR-IOM, TASC Laboratory, Basovizza S S 14 km 163.5, 34149 Trieste (Italy)

2011-05-06

Ordered arrays of nanoelectrodes for electrochemical use are prepared by electron beam lithography (EBL) using polycarbonate as a novel e-beam resist. The nanoelectrodes are fabricated by patterning arrays of holes in a thin film of polycarbonate spin-coated on a gold layer on Si/Si{sub 3}N{sub 4} substrate. Experimental parameters for the successful use of polycarbonate as high resolution EBL resist are optimized. The holes can be filled partially or completely by electrochemical deposition of gold. This enables the preparation of arrays of nanoelectrodes with different recession degree and geometrical characteristics. The polycarbonate is kept on-site and used as the insulator that separates the nanoelectrodes. The obtained nanoelectrode arrays (NEAs) exhibit steady state current controlled by pure radial diffusion in cyclic voltammetry for scan rates up to approximately 50 mV s{sup -1}. Electrochemical results showed satisfactory agreement between experimental voltammograms and suitable theoretical models. Finally, the peculiarities of NEAs versus ensembles of nanoelectrodes, obtained by membrane template synthesis, are critically evaluated.

Current Abstracts Nuclear Reactors and Technology

Energy Technology Data Exchange (ETDEWEB)

Bales, J.D.; Hicks, S.C. [eds.

1993-01-01

This publication Nuclear Reactors and Technology (NRT) announces on a monthly basis the current worldwide information available from the open literature on nuclear reactors and technology, including all aspects of power reactors, components and accessories, fuel elements, control systems, and materials. This publication contains the abstracts of DOE reports, journal articles, conference papers, patents, theses, and monographs added to the Energy Science and Technology Database during the past month. Also included are US information obtained through acquisition programs or interagency agreements and international information obtained through acquisition programs or interagency agreements and international information obtained through the International Energy Agency`s Energy Technology Data Exchange or government-to-government agreements. The digests in NRT and other citations to information on nuclear reactors back to 1948 are available for online searching and retrieval on the Energy Science and Technology Database and Nuclear Science Abstracts (NSA) database. Current information, added daily to the Energy Science and Technology Database, is available to DOE and its contractors through the DOE Integrated Technical Information System. Customized profiles can be developed to provide current information to meet each user`s needs.

Textural analyses of carbon fiber materials by 2D-FFT of complex images obtained by high frequency eddy current imaging (HF-ECI)

Science.gov (United States)

Schulze, Martin H.; Heuer, Henning

2012-04-01

Carbon fiber based materials are used in many lightweight applications in aeronautical, automotive, machine and civil engineering application. By the increasing automation in the production process of CFRP laminates a manual optical inspection of each resin transfer molding (RTM) layer is not practicable. Due to the limitation to surface inspection, the quality parameters of multilayer 3 dimensional materials cannot be observed by optical systems. The Imaging Eddy- Current (EC) NDT is the only suitable inspection method for non-resin materials in the textile state that allows an inspection of surface and hidden layers in parallel. The HF-ECI method has the capability to measure layer displacements (misaligned angle orientations) and gap sizes in a multilayer carbon fiber structure. EC technique uses the variation of the electrical conductivity of carbon based materials to obtain material properties. Beside the determination of textural parameters like layer orientation and gap sizes between rovings, the detection of foreign polymer particles, fuzzy balls or visualization of undulations can be done by the method. For all of these typical parameters an imaging classification process chain based on a high resolving directional ECimaging device named EddyCus® MPECS and a 2D-FFT with adapted preprocessing algorithms are developed.

Higher Mellin moments for charged current DIS

International Nuclear Information System (INIS)

Rogal, M.; Moch, S.

2007-06-01

We report on our recent results for deep-inelastic neutrino(ν)-proton(P) scattering. We have computed the perturbative QCD corrections to three loops for the charged current structure functions F 2 , F L and F 3 for the combination νP- anti νP. In leading twist approximation we have calculated the first six odd-integer Mellin moments in the case of F 2 and F L and the first six even-integer moments in the case of F 3 . As a new result we have obtained the coefficient functions to O(α 3 s ) and we have found the corresponding anomalous dimensions to agree with known results in the literature. (orig.)

Study on UPF Harmonic Current Detection Method Based on DSP

Energy Technology Data Exchange (ETDEWEB)

Zhao, H J [Northwestern Polytechnical University, Xi' an 710072 (China); Pang, Y F [Xi' an University of Technology, Xi' an 710048 (China); Qiu, Z M [Xi' an University of Technology, Xi' an 710048 (China); Chen, M [Northwestern Polytechnical University, Xi' an 710072 (China)

2006-10-15

Unity power factor (UPF) harmonic current detection method applied to active power filter (APF) is presented in this paper. The intention of this method is to make nonlinear loads and active power filter in parallel to be an equivalent resistance. So after compensation, source current is sinusoidal, and has the same shape of source voltage. Meanwhile, there is no harmonic in source current, and the power factor becomes one. The mathematic model of proposed method and the optimum project for equivalent low pass filter in measurement are presented. Finally, the proposed detection method applied to a shunt active power filter experimental prototype based on DSP TMS320F2812 is developed. Simulation and experiment results indicate the method is simple and easy to implement, and can obtain the real-time calculation of harmonic current exactly.

Current account dynamics with rule of thumb consumers

Directory of Open Access Journals (Sweden)

Rodrigo M. Pereira

2011-06-01

Full Text Available In this paper the idea of rule of thumb consumption, in which some households do not behave according to the Permanent Income Hypothesis, is applied to a small open economy framework. A model of current account with rule of thumb individuals and habit formation is presented and estimated for five different countries. Two parameters of the model are of particular interest: the share of domestic income that accrues to rule of thumb individuals and the coefficient of habit formation. Using current account data, the results obtained here support the view that rule of thumb behavior plays a major role in the economy. Moreover, the estimated habit formation coefficients are mostly small and nonsignificant.

Current status of multi-detector row helical CT in imaging of adult ...

African Journals Online (AJOL)

Current status of multi-detector row helical CT in imaging of adult acquired pancreatic diseases and assessing surgical neoplastic resectability. ... The presence of inflammation, masses, and vascular invasion was evaluated and interpreted images were obtained during each phase. Results were compared with surgery, ...

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

International Nuclear Information System (INIS)

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.

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

Science.gov (United States)

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.

Conduction mechanism of leakage current due to the traps in ZrO2 thin film

International Nuclear Information System (INIS)

Seo, Yohan; Lee, Sangyouk; An, Ilsin; Jeong, Heejun; Song, Chulgi

2009-01-01

In this work, a metal-oxide-semiconductor capacitor with zirconium oxide (ZrO 2 ) gate dielectric was fabricated by an atomic layer deposition (ALD) technique and the leakage current characteristics under negative bias were studied. From the result of current–voltage curves there are two possible conduction mechanisms to explain the leakage current in the ZrO 2 thin film. The dominant mechanism is the space charge limited conduction in the high-electric field region (1.5–5.0 MV cm −1 ) while the trap-assisted tunneling due to the existence of traps is prevailed in the low-electric field region (0.8–1.5 MV cm −1 ). Conduction caused by the trap-assisted tunneling is found from the experimental results of a weak temperature dependence of current, and the trap barrier height is obtained. The space charge limited conduction is evidenced, for different temperatures, by Child's law dependence of current density versus voltage. Child's law dependence can be explained by considering a single discrete trapping level and we can obtain the activation energy of 0.22 eV

Comparison of NDT techniques to evaluate CFRP. Results obtained in a MAIzfp round robin test

Energy Technology Data Exchange (ETDEWEB)

Grosse, Christian U. [Technische Univ. Muenchen (Germany). Chair of Non-destructive Testing; Goldammer, Matthias; Grager, Jan-Carl [Siemens AG Corporate Technology, Muenchen (Germany); and others

2016-10-01

Fiber reinforced polymeric materials are used for lightweight constructions and are an integral part of cars, airplanes or rotor blades of wind turbines. Nondestructive testing (NDT) methods play an increasing role concerning the manufacturing process and the inspection during lifetime. The selection of the best NDT technique for a certain application depends - of course - on many factors including the type, position and size of the defect to be detected but also on secondary issues like accessibility, automation, testing costs, reliability and resolution to mention only some. For the more technical-scientific part of these issues, the determination of the probability of detection (PoD) plays a significant role. Early in the design process questions should be raised concerning the probability with which certain attribute of interest (a defect that has an effect on the structural behavior) can be detected (and localized) in a certain construction. Several defect types have been identified to be critical like impact damages, undulations and porosity. Test samples out of differently processed Carbon Fiber-Reinforced Polymers (CFRP) as used in the automotive or aeronautical industry have been produced including defects of different type and size. In order to determine the PoD and to check whether a technique is applicable the different partners applied a broad variety of selected NDT techniques including Micro CT, Ultrasound (including phased-array and air-coupled UT), Active Thermography, Eddy Current, Vibration and Visual Analysis and Local Acoustic Resonance Spectroscopy (LARS). The presentation will summarize some of the results of the experiments and ongoing data analysis.

Comparison of NDT techniques to evaluate CFRP. Results obtained in a MAIzfp round robin test

International Nuclear Information System (INIS)

Grosse, Christian U.

2016-01-01

Fiber reinforced polymeric materials are used for lightweight constructions and are an integral part of cars, airplanes or rotor blades of wind turbines. Nondestructive testing (NDT) methods play an increasing role concerning the manufacturing process and the inspection during lifetime. The selection of the best NDT technique for a certain application depends - of course - on many factors including the type, position and size of the defect to be detected but also on secondary issues like accessibility, automation, testing costs, reliability and resolution to mention only some. For the more technical-scientific part of these issues, the determination of the probability of detection (PoD) plays a significant role. Early in the design process questions should be raised concerning the probability with which certain attribute of interest (a defect that has an effect on the structural behavior) can be detected (and localized) in a certain construction. Several defect types have been identified to be critical like impact damages, undulations and porosity. Test samples out of differently processed Carbon Fiber-Reinforced Polymers (CFRP) as used in the automotive or aeronautical industry have been produced including defects of different type and size. In order to determine the PoD and to check whether a technique is applicable the different partners applied a broad variety of selected NDT techniques including Micro CT, Ultrasound (including phased-array and air-coupled UT), Active Thermography, Eddy Current, Vibration and Visual Analysis and Local Acoustic Resonance Spectroscopy (LARS). The presentation will summarize some of the results of the experiments and ongoing data analysis.

Modelling of Leakage Current Through Double Dielectric Gate Stack in Metal Oxide Semiconductor Capacitor

International Nuclear Information System (INIS)

Fatimah A Noor; Mikrajuddin Abdullah; Sukirno; Khairurrijal

2008-01-01

In this paper, we have derived analytical expression of leakage current through double barriers in Metal Oxide Semiconductor (MOS) capacitor. Initially, electron transmittance through the MOS capacitor was derived by including the coupling between the transverse and longitudinal energies. The transmittance was then employed to obtain leakage current through the double barrier. In this model, we observed the effect of electron velocity due to the coupling effect and the oxide thickness to the leakage current. The calculated results showed that the leakage current decreases as the electron velocity increases. (author)

Comparative analysis of the results obtained by computer code ASTEC V2 and RELAP 5.3.2 for small leak ID 80 for VVER 1000

International Nuclear Information System (INIS)

Atanasova, B.; Grudev, P.

2011-01-01

The purpose of this report is to present the results obtained by simulation and subsequent analysis of emergency mode for small leak with ID 80 for WWER 1000/B320 - Kozloduy NPP Units 5 and 6. Calculations were performed with the ASTEC v2 computer code used for calculation of severe accident, which was designed by French and German groups - IRSN and GRS. Integral RELAP5 computer code is used as a reference for comparison of results. The analyzes are focused on the processes occurring in reactor internals phase of emergency mode with significant core damage. The main thermohydraulic parameters, start of reactor core degradation and subsequent fuel relocalization till reactor vessel failure are evaluated in the analysis. RELAP5 computer code is used as a reference code to compare the results obtained till early core degradation that occurs after core stripping and excising of fuel temperature above 1200 0 C

Numerical analysis of the stability of HTS power cable under fault current considering the gaps in the cable

International Nuclear Information System (INIS)

Fang, J.; Li, H.F.; Zhu, J.H.; Zhou, Z.N.; Li, Y.X.; Shen, Z.; Dong, D.L.; Yu, T.; Li, Z.M.; Qiu, M.

2013-01-01

Highlights: •The equivalent circuit equations and the heat balance equations were established. •The current distributions of the HTS cable under fault current were obtained. •The temperature curves of conductor layers under fault current were obtained. •The effect of the gap liquid nitrogen on the thermal characteristics was studied. -- Abstract: During the operation of a high temperature superconducting power cable in a real grid, the power cable can be impacted inevitably by large fault current. The study on current distribution and thermal characteristics in the cable under fault current is the foundation to analyze its stability. To analyze the operation situation of 110 kV/3 kA class superconducting cable under the fault current of 25 kA rms for 3 s, the equivalent circuit equations and heat balance equations were established. The current distribution curves and the temperature distribution curves were obtained. The liquid nitrogen which exists in the gaps of HTS cable was taken into consideration, the influence of gap liquid nitrogen on the thermal characteristics was investigated. The analysis results can be used to estimate the security and stability of the superconducting cable

Numerical analysis of the stability of HTS power cable under fault current considering the gaps in the cable

Energy Technology Data Exchange (ETDEWEB)

Fang, J., E-mail: fangseer@sina.com [School of Electrical Engineering, Beijing Jiaotong University, Beijing 100044 (China); Li, H.F. [School of Electrical Engineering, Beijing Jiaotong University, Beijing 100044 (China); Zhu, J.H.; Zhou, Z.N. [China Electric Power Research Institute, Beijing 100192 (China); Li, Y.X.; Shen, Z.; Dong, D.L.; Yu, T. [School of Electrical Engineering, Beijing Jiaotong University, Beijing 100044 (China); Li, Z.M.; Qiu, M. [China Electric Power Research Institute, Beijing 100192 (China)

2013-11-15

Highlights: •The equivalent circuit equations and the heat balance equations were established. •The current distributions of the HTS cable under fault current were obtained. •The temperature curves of conductor layers under fault current were obtained. •The effect of the gap liquid nitrogen on the thermal characteristics was studied. -- Abstract: During the operation of a high temperature superconducting power cable in a real grid, the power cable can be impacted inevitably by large fault current. The study on current distribution and thermal characteristics in the cable under fault current is the foundation to analyze its stability. To analyze the operation situation of 110 kV/3 kA class superconducting cable under the fault current of 25 kA{sub rms} for 3 s, the equivalent circuit equations and heat balance equations were established. The current distribution curves and the temperature distribution curves were obtained. The liquid nitrogen which exists in the gaps of HTS cable was taken into consideration, the influence of gap liquid nitrogen on the thermal characteristics was investigated. The analysis results can be used to estimate the security and stability of the superconducting cable.

Considerations on ECFH current drive and bootstrap current for W VII-X

International Nuclear Information System (INIS)

Gasparino, U.; Maassberg, H.

1988-01-01

Low shear is the characteristic of all proposed Wendelstein VII-X configurations. To avoid low harmonic rational numbers within the rotational transform profile, the current contribution to the rotational transform, Δt a α I/B, should be typically less than 10%. This leads to an upper limit of 50 kA (at B = 2.5 T) for the tolerable net toroidal current. A considerable net toroidal current (bootstrap current) is expected by neoclassical theory in the plateau and the low-collisionality regimes. Both radial transport as well as the bootstrap current densities depend sensitively on the magnetic configuration (see A. Montvai, this workshop). In case of an axisymmetric configuration with dimension and plasma parameters as predicted for the high- regime of WVII-X ( ∼ 5%), this current (∼ 0.5/1 MA) would dominate the rotational transform profile. This requires a reduction of magnitude of the bootstrap current to some % of the value of an equivalent tokamak. This reduction must act on the current profile itself and should not be merely obtained by having two channels of currents of different sign at different radii. Due to the possibility of controlling absorbed power and driven current profiles, electron cyclotron waves are a natural candidate for current profile control. Linear calculations show the possibility to drive a counteracting current with a profile similar to the bootstrap one. For ∼ 5% conditions, however, the optimium current drive efficiency (η ∼ 10 kA per MW) is far too low to make ECF-current drive suitable

Two-section linear direct-current accelerator of 1.2 MeV electrons. Mean beam current of 50 mA

International Nuclear Information System (INIS)

Alimov, A.S.; Ermakov, D.I.; Ishkhanov, B.S.; Shvedunov, V.I.; Sakharov, V.P.; Trower, W.P.

2002-01-01

The theoretical and experimental results, obtained by simulation, creation and start-up of the two-section linear electron accelerator, are presented. The following beam parameters: beam current of 49 mA, mean energy of 1.2 MeV, of 59 kV, normalized emittance of 11 mm mrad are determined on the basis of the data on the beam dynamics simulation and the accelerating structure optimization. Special attention is paid to the choice of the version of the SHF-supply system of the two-section accelerator. The version of the SHF-supply system, based on the sections phasing, operating in the auto-oscillation model by means of the synchronizing signal from the feedback chain of the first section into the feedback chain of the second section, is considered. The electron beam parameters on the accelerator outlet (beam current - 44 mA, beam energy - 1.15 MeV, beam efficiency - 50.6 kW) proved to be close to the simulation results [ru

Low-Frequency Pulsed Current Versus Kilohertz-Frequency Alternating Current: A Scoping Literature Review.

Science.gov (United States)

Vaz, Marco Aurélio; Frasson, Viviane Bortoluzzi

2018-04-01

To compare the effectiveness of low-frequency pulsed current versus kilohertz-frequency alternating current in terms of evoked force, discomfort level, current intensity, and muscle fatigability; to discuss the physiological mechanisms of each neuromuscular electrical stimulation type; and to determine if kilohertz-frequency alternating current is better than low-frequency pulsed current for clinical treatment. Articles were obtained from PubMed, Scopus, Cochrane Central Register of Controlled Trials, CINAHL, MEDLINE, and SPORTSDiscus databases using the terms Russian current or kilohertz current or alternating current or pulsed current or Aussie current and torque or discomfort or fatigue or current intensity, and through citation tracking up to July 2017. Two independent reviewers selected studies comparing the use of the 2 neuromuscular electrical stimulation currents. Studies describing maximal current intensity tolerated and the main effects of the 2 different current types on discomfort, muscle force, and fatigability were independently reviewed. Data were systematized according to (1) methodology; (2) electrical current characteristics; and (3) outcomes on discomfort level, evoked force, current intensity, and muscle fatigability. The search revealed 15 articles comparing the 2 current types. Kilohertz-frequency alternated current generated equal or less force, similar discomfort, similar current intensity for maximal tolerated neuromuscular electrical stimulation, and more fatigue compared with low-frequency pulsed current. Similar submaximal levels of evoked force revealed higher discomfort and current intensity for kilohertz-frequency alternated current compared with low-frequency pulsed current. Available evidence does not support the idea that kilohertz-frequency alternated current is better than low-frequency pulsed current for strength training and rehabilitation. Copyright © 2017 American Congress of Rehabilitation Medicine. Published by Elsevier

Obtaining of ceramics biphasic dense and porous

International Nuclear Information System (INIS)

Pallone, E.M.J.A.; Rigo, E.C.S.; Fraga, A.F.

2010-01-01

Among the bioceramic hydroxyapatite (HAP) and beta-tricalcium phosphate (beta-TCP) are materials commonly used in biomedical field. Their combined properties result in a material with absorbable and at the same time with bioactive surface. Called biphasic ceramics such materials respond more quickly when exposed to physiological environment. In this work, powders of HAP/beta-TCP were obtained by chemical precipitation. After obtaining the post-phase was added at a ratio of 0, 15% and 30w% aqueous solutions of corn starch in order to obtain porous bodies. After mixing the resulting solutions were dried, resigned in tablet form and sintered at 1300 deg C. The initial powder was characterized by X-ray diffraction with Rietveld refinement to quantify the phases present. Bodies-of-evidence has been characterized by calculating the bulk density, X-ray diffraction (XRD), scanning electron microscopy and diametral compression. (author)

Review of recent LHCb results and prospects for Run II

CERN Document Server

Hicheur, A

2015-01-01

As first Run II data acquisition has begun, it is useful to expose the pending questions by reviewing some of the most recent results obtained with Run I data analyses. Early results of the current data taking and middle-term prospects are also shown to illustrate the efficiency of the acquisition and analysis chain.

Review of recent LHCb results and expectations for Run II

CERN Document Server

Hicheur, Adlene

2016-01-01

As first Run II data acquisition has begun, it is useful to expose the pending questions by reviewing some of the most recent results obtained with Run I data analyses. Early results of the current data taking and middle-term prospects are also shown to illustrate the efficiency of the acquisition and analysis chain.

Limiting currents of overcompensated electron beams

International Nuclear Information System (INIS)

Malafaev, V.A.

1990-01-01

A possibility of producing recompensated electron beam and increasing its limiting currents in the magnetic field is experimentally investigated. It is shown that such a possibility is realized when the beam is surrounded by a cylindrical net placed into the tube located under the positive potential relative to the net. In this case an increase of limiting current at the expense of increasing the ion life time, takes place. Current, exceeding the Pierce threshold 1.5 times, is obtained

Preliminary Results from Duplex Procedure for Obtain of Fe Based Materials for Automotive Applications

Science.gov (United States)

Crăciun, R. C.; Stanciu, S.; Geantă, V.; Voiculescu, I.; Manole, V.; Gârneţ, I. A.; Alexandru, A.; Cimpoesu, N.; Săndulache, F.

2017-06-01

Abstract Iron based materials still represent a high percentage from metallic materials used in industry, in general, and in automotive industry, in particular. In this case we used a duplex process in order to obtain the FeMnSiAl experimental alloy for a more efficient use of various units. In the first stage iron, manganese, silicon and aluminum were melted and mixed together using arc melting technology and for the second stage the alloy was re-melt for homogeneity in an induction furnace. Chemical composition, after each melting step, was analyzed using EDS Bruker detector for various areas and microstructural characterization using SEM, VegaTescan LMH II with SE detector, equipment. This alloy is proposed as a metallic approach of mechanical dumpers used in automotive industry for low and medium impact contacts.

INVESTIGATION OF MICROPROCESSOR CURRENT PROTECTION LINES WITH IMPROVED INDICES OF TECHNICAL PERFECTION

Directory of Open Access Journals (Sweden)

E. V. Buloichyk

2014-01-01

Full Text Available Technical perfection improvement of microprocessor current protection of distribution networks lines is provided by introduction of asymmetrical fault mode determination and fault location functions in the algorithm of its functioning. As a result of computing experiment the basic indices of the technical perfection of current protection have been obtained in the paper. The paper proves high efficiency of the proposed methods that ensure selective and proper operation in the different modes of the controlled line.

Transition currents in diagonal spin basis

International Nuclear Information System (INIS)

Rogalev, R.N.

1996-01-01

Scalar and pseudoscalar densities, vector, pseudovector and tensor currents are expressed in terms of momentum and spin vectors of the corresponding particles in an explicitly covariant way. The obtained expressions are free of singularities and make it possible to draw a number of identities, which relate axial-vector, vector and tensor currents to each other. 8 refs

Current Results of NEUTRINO-4 Experiment

Science.gov (United States)

Serebrov, A.; Ivochkin, V.; Samoilov, R.; Fomin, A.; Polyushkin, A.; Zinoviev, V.; Neustroev, P.; Golovtsov, V.; Chernyj, A.; Zherebtsov, O.; Martemyanov, V.; Tarasenkov, V.; Aleshin, V.; Petelin, A.; Izhutov, A.; Tuzov, A.; Sazontov, S.; Ryazanov, D.; Gromov, M.; Afanasiev, V.; Zaytsev, M.; Chaikovskii, M.

2017-12-01

The main goal of experiment “Neutrino-4” is to search for the oscillation of reactor antineutrino to a sterile state. Experiment is conducted on SM-3 research reactor (Dimitrovgrad, Russia). Data collection with full-scale detector with liquid scintillator volume of 3m3 was started in June 2016. We present the results of measurements of reactor antineutrino flux dependence on the distance in range 6- 12 meters from the center of the reactor. At that distance range, the fit of experimental dependence has good agreement with the law 1/L2. Which means, at achieved during the data collecting accuracy level oscillations to sterile state are not observed. In addition, the spectrum of prompt signals of neutrino-like events at different distances have been presented.

Self-consistent neutral point current and fields from single particle dynamics

International Nuclear Information System (INIS)

Martin, R.F. Jr.

1988-01-01

In order to begin to build a global model of the magnetotail-auroral region interaction, it is of interest to understand the role of neutral points as potential centers of particle energization in the tail. In this paper, the single particle current is calculated near a magnetic neutral point with magnetotail properties. This is balanced with the Ampere's law current producing the magnetic field to obtain the self-consistent electric field for the problem. Also calculated is the current-electric field relationship and, in the regime where this relation is linear, an effective conductivity. Results for these macroscopic quantities are surprisingly similar to the values calculated for a constant normal field current sheet geometry. Application to magnetotail modeling is discussed. 11 references

Do Changes in Current Flow as a Result of Arrays of Tidal Turbines Have an Effect on Benthic Communities?

Science.gov (United States)

Kregting, Louise; Elsaesser, Bjoern; Kennedy, Robert; Smyth, David; O'Carroll, Jack; Savidge, Graham

2016-01-01

Arrays of tidal energy converters have the potential to provide clean renewable energy for future generations. Benthic communities may, however, be affected by changes in current speeds resulting from arrays of tidal converters located in areas characterised by strong currents. Current speed, together with bottom type and depth, strongly influence benthic community distributions; however the interaction of these factors in controlling benthic dynamics in high energy environments is poorly understood. The Strangford Lough Narrows, the location of SeaGen, the world's first single full-scale, grid-compliant tidal energy extractor, is characterised by spatially heterogenous high current flows. A hydrodynamic model was used to select a range of benthic community study sites that had median flow velocities between 1.5-2.4 m/s in a depth range of 25-30 m. 25 sites were sampled for macrobenthic community structure using drop down video survey to test the sensitivity of the distribution of benthic communities to changes in the flow field. A diverse range of species were recorded which were consistent with those for high current flow environments and corresponding to very tide-swept faunal communities in the EUNIS classification. However, over the velocity range investigated, no changes in benthic communities were observed. This suggested that the high physical disturbance associated with the high current flows in the Strangford Narrows reflected the opportunistic nature of the benthic species present with individuals being continuously and randomly affected by turbulent forces and physical damage. It is concluded that during operation, the removal of energy by marine tidal energy arrays in the far-field is unlikely to have a significant effect on benthic communities in high flow environments. The results are of major significance to developers and regulators in the tidal energy industry when considering the environmental impacts for site licences.

On Current Drive and Wave Induced Bootstrap Current in Toroidal Plasmas

International Nuclear Information System (INIS)

Hellsten, T.; Johnson, T.

2008-01-01

A comprehensive treatment of wave-particle interactions in toroidal plasmas including collisional relaxation, applicable to heating or anomalous wave induced transport, has been obtained by using Monte Carlo operators satisfying quasi-neutrality. This approach enables a self-consistent treatment of wave-particle interactions applicable to the banana regime in the neoclassical theory. It allows an extension into a regime with large temperature and density gradients, losses and transport of particles by wave-particle interactions making the method applicable to transport barriers. It is found that at large gradients the relationship between radial electric field, parallel velocity, temperature and density gradient in the neoclassical theory is modified such that coefficient in front of the logarithmic ion temperature gradient, which in the standard neoclassical theory is small and counteracts the electric field caused by the density gradient, now changes sign and contributes to the built up of the radial electric field. The possibility to drive current by absorbing the waves on trapped particles has been studied and how the wave-particle interactions affect the bootstrap current. Two new current drive mechanisms are studied: current drive by wave induced bootstrap current and selective detrapping into passing orbits by directed waves.

OBTAINING AND PROPERTIES OF AgInS2 FILMS

Directory of Open Access Journals (Sweden)

M. A. Abdullaev

2016-01-01

Full Text Available Aim. The aim is to obtain AgInS2 films and study their electrical and optical properties.Methods. The samples of thin AgInS2 films for measurement were obtained by the method of magnetron sputtering with direct current. The structure, phase and elemental composition were studied using DRON-2 X-ray diffractometer (СuKа - radiation and the microscope LEO-1450 with EDS attachment for X-ray microanalysis. The optical transmittance and absorption were examined using MDR-2 monochromator in the wavelength range of 400-800 nm with the Keitley electrometer and FD-10G; we applied the spectral resolution of ± 1 meV. The electrical conductivity, Hall effect was measured by the four-point probe method with indium ohmic contacts. Measurements were carried out in the temperature range of 77-400 K.Findings. We obtained indium disulfide and silver films with the thickness of up to 1 μm on quartz substrates by magnetron sputtering. It is shown that increasing the substrate temperature to about 450 0С allows to obtain single phase film with a chalcopyrite structure with a band gap of 1.88 eV and high absorption coefficient (>104см-1.Conclusions. The possibility of obtaining films in a wide range of the electrical resistance and variation of the electrical parameters at constant stoichiometry is of interest for efficient technologies of phototransduction.

[Nutritional screening before surgery for esophageal cancer - current status and evaluation results].

Science.gov (United States)

Shimakawa, Takeshi; Asaka, Shinich; Sagawa, Masano; Shimazaki, Asako; Yamaguchi, Kentaro; Usui, Takebumi; Yokomizo, Hajime; Shiozawa, Shunichi; Yoshimatsu, Kazuhiko; Katsube, Takao; Naritaka, Yoshihiko

2014-10-01

The incidence of postoperative complications and mortality are usually higher in patients with preoperative malnutrition. Malnutrition often preexists, particularly in patients undergoing surgery for esophageal cancer, which is substantially invasive. It is therefore important to understand the nutritional condition of patients and actively control perioperative nutrition.Our hospital has been providing nutritional status screening for patients before resection of esophageal cancer, and we report the current status and evaluation results in this article.This screening included 158 patients requiring radical resection of esophageal cancer.Age, comorbidity with diabetes, body mass index(BMI), serum albumin(Alb), Onodera's prognostic nutritional index(PNI), and Glasgow prognostic score(GPS)were used as nutritional indicators to stratify patients for analysis.Evaluation parameters included the incidence of postoperative complications(any complication, pulmonary complications, psychiatric disorder, and anastomotic leakage)and rates of long-term postoperative hospitalization.The analysis indicated that age, BMI, serum Alb, PNI, and GPS are useful for predicting the onset of postoperative complications and prolonged postoperative hospitalization.For such patients, more active nutritional control should be provided.

Eddy current loss calculation and thermal analysis of axial-flux permanent magnet couplers

Directory of Open Access Journals (Sweden)

Di Zheng

2017-02-01

Full Text Available A three-dimensional magnetic field analytical model of axial-flux permanent magnet couplers is presented to calculate the eddy current loss, and the prediction of the copper plate temperature under various loads is analyzed. The magnetic field distribution is calculated, and then the eddy current loss is obtained, with the magnetic field analytical model established in cylindrical coordinate. The influence of various loads on eddy current loss is analyzed. Furthermore, a thermal model of axial-flux permanent magnet couplers is established by taking the eddy current loss as the heat source, using the electromagnetic-thermal coupled method. With the help of the thermal model, the influence of various loads on copper plate temperature rise is also analyzed. The calculated results are compared with the results of finite element method and measurement. The comparison results confirm the validity of the magnetic field analytical model and thermal model.

Fermentation Results and Chemical Composition of Agricultural Distillates Obtained from Rye and Barley Grains and the Corresponding Malts as a Source of Amylolytic Enzymes and Starch.

Science.gov (United States)

Balcerek, Maria; Pielech-Przybylska, Katarzyna; Dziekońska-Kubczak, Urszula; Patelski, Piotr; Strąk, Ewelina

2016-10-01

The objective of this study was to determine the efficiency of rye and barley starch hydrolysis in mashing processes using cereal malts as a source of amylolytic enzymes and starch, and to establish the volatile profile of the obtained agricultural distillates. In addition, the effects of the pretreatment method of unmalted cereal grains on the physicochemical composition of the prepared mashes, fermentation results, and the composition of the obtained distillates were investigated. The raw materials used were unmalted rye and barley grains, as well as the corresponding malts. All experiments were first performed on a semi-technical scale, and then verified under industrial conditions in a Polish distillery. The fermentable sugars present in sweet mashes mostly consisted of maltose, followed by glucose and maltotriose. Pressure-thermal treatment of unmalted cereals, and especially rye grains, resulted in higher ethanol content in mashes in comparison with samples subjected to pressureless liberation of starch. All agricultural distillates originating from mashes containing rye and barley grains and the corresponding malts were characterized by low concentrations of undesirable compounds, such as acetaldehyde and methanol. The distillates obtained under industrial conditions contained lower concentrations of higher alcohols (apart from 1-propanol) than those obtained on a semi-technical scale.

Fermentation Results and Chemical Composition of Agricultural Distillates Obtained from Rye and Barley Grains and the Corresponding Malts as a Source of Amylolytic Enzymes and Starch

Directory of Open Access Journals (Sweden)

Maria Balcerek

2016-10-01

Full Text Available The objective of this study was to determine the efficiency of rye and barley starch hydrolysis in mashing processes using cereal malts as a source of amylolytic enzymes and starch, and to establish the volatile profile of the obtained agricultural distillates. In addition, the effects of the pretreatment method of unmalted cereal grains on the physicochemical composition of the prepared mashes, fermentation results, and the composition of the obtained distillates were investigated. The raw materials used were unmalted rye and barley grains, as well as the corresponding malts. All experiments were first performed on a semi-technical scale, and then verified under industrial conditions in a Polish distillery. The fermentable sugars present in sweet mashes mostly consisted of maltose, followed by glucose and maltotriose. Pressure-thermal treatment of unmalted cereals, and especially rye grains, resulted in higher ethanol content in mashes in comparison with samples subjected to pressureless liberation of starch. All agricultural distillates originating from mashes containing rye and barley grains and the corresponding malts were characterized by low concentrations of undesirable compounds, such as acetaldehyde and methanol. The distillates obtained under industrial conditions contained lower concentrations of higher alcohols (apart from 1-propanol than those obtained on a semi-technical scale.

Recent results from neutrino interactions in heavy neon

International Nuclear Information System (INIS)

Baltay, C.; Caroumbalis, D.; French, H.

1978-01-01

Recent results are reported from an analysis of 100,000 pictures of the Fermilab 15 ft. bubble chamber filled with heavy neon and exposed to the double horn focused, wideband ν/sub μ/ beam. There were 164 dilepton (μ - e + ) events with 33 vees, in good agreement with the GIM model of charm production. Also the production of the charmed D 0 meson, followed by the decay D 0 → K 0 π + π - , at a rate of (0.7 +- 0.2)% of all charged current events were observed. Searches were carried out for charm changing neutral current processes and for heavy lepton production, both with negative results; the upper limits obtained in these searches are given

Surfzone Currents Over Irregular Bathymetry: Drifter Observations and Numerical Model Results

Science.gov (United States)

Schmidt, W. E.; Slinn, D. N.; Guza, R. T.

2002-12-01

Surfzone currents on alongshore variable bathymetry were observed with recently developed GPS-tracked drifters and numerically modeled with the time-dependent, nonlinear shallow water equations. These currents, forced by alongshore inhomogeneous pressure and radiation stress gradients, contain flow features difficult to resolve with fixed instrument arrays, such as rips, eddies, and meanders. Drifters were repeatedly released and recovered near Scripps Beach, La Jolla, California, in July 2000, 2001, and 2002. The most recent deployment of 10 drifters yielded about 32 hours of drifter data for each 5 hour deployment day. Offshore wave heights were moderate, between 0.3-1.0 m. The bathymetry, measured over a 600-700 m alongshore span with a GPS- and sonar-equipped jetski (2001 and 2002 deployments), was alongshore inhomogeneous primarily where an irregularly shaped bar-trough feature spanned the surf zone. The model simulations suggest that the alongshore inhomogeneous bathymetry strongly influences the location and strength of the observed flow features. Research supported by the California Sea Grant College Program and the Office of Naval Research.

Results from CrIS-ATMS Obtained Using the AIRS Science Team Retrieval Methodology

Science.gov (United States)

Susskind, Joel; Kouvaris, Louis C.; Iredell, Lena

2013-01-01

which significantly improved results of AIRS Version-6. Version-5.70 CrIS/ATMS temperature profile and surface skin temperature retrievals are of very good quality, and are better than AIRS Version-5 retrievals, but are still significantly poorer than those of AIRS Version-6. CrIS/ATMS retrievals should improve when a Neural-Net start-up system is ready for use. We also examined CrIS/ATMS retrievals generated by NOAA using their NUCAPS retrieval algorithm, which is based on earlier versions of the AIRS Science Team retrieval algorithms. We show that the NUCAPS algorithm as currently configured is not well suited for climate monitoring purposes.

Vacuum energies due to delta-like currents: multipole interactions

International Nuclear Information System (INIS)

Barone, F.A.; Borges, K.; Flores-Hidalgo, G.

2009-01-01

Full text. This work is devoted to a study about the quantum description of multipoles distributions by the use of external static currents concentrated along specific regions of space. For this task we consider models of bosonic quantum fields (scalar and electromagnetic fields) interacting with external currents which simulate the presence of charges, dipoles and quadrupoles distributions along D-dimensional static branes. Along the work we consider models in d+D+1 dimensions described by a quantum field coupled with an external current composed by two parts: the first one concentrated along a D-brane and the other one concentrated at a given point of space. This last part represents a point-like test-charge which is used to investigate the force field produced by the former one. Specifically, we consider models for the scalar field, with and without mass, coupled to currents describing distributions of charges, dipoles and quadrupoles currents along D-branes. These currents are given, respectively, by a Dirac's delta function, a directional derivative of a Dirac's delta function and the second derivative of a Dirac's delta function (coupled with a second rank tensor). We also extend the previous results for the electromagnetic case in order to bring them to more realistic contexts. We show that, as expected, there is an overall minus sing in comparing the results obtained for the scalar and electromagnetic fields. (author)

Development of high current injector for tandem accelerator

Energy Technology Data Exchange (ETDEWEB)

Baba, Takashi; Iwamoto, Eiji [Nissin - High Voltage Co. Ltd., Kyoto (Japan); Kishimoto, Naoki; Saito, Tetsuya; Mori, Yoshiharu

1997-02-01

The development of the electrostatic type tandem accelerators has been carried out so far, but by the recent remarkable progress of negative ion sources, the beam current which was inconceivable so far has become obtainable, and the use as the electrostatic type tandem accelerators is expanding rapidly. The problem which must be solved in the development of a high energy, large current heavy ion injection device is the development of an injector. As to the generation of negative ions, by the development of plasma sputter negative ion sources, the almost satisfactory performance has been obtained in beam current, emittance, life and so on, but as for the transport and control of generated negative ion beam, there is the large problem of spatial charge effect. This time, the verifying test on this problem was carried out, therefore, its contents and results are reported. The equipment which was developed this time was delivered to the Institute for Materials Research. Its specifications are shown. The whole constitution, negative ion source, and beam transport system are described. Beam generation test and spatial charge effect test are reported. The test stand was made, and in the verifying test, the maximum beams of 4 mA in Cu and 3 mA in Ni were able to be generated and transported. The effect of the countermeasures to spatial charge effect was confirmed. (K.I.)

On-electrode autonomous current generator for multi-frequency EIT

International Nuclear Information System (INIS)

Jivet, I; Dragoi, B

2008-01-01

The paper presents an autonomous programmable current generator module for multi-frequency EIT systems. The module incorporates all stages from the sine wave generation with frequency and amplitude tuning, D/A converter and filter, a high output resistance voltage-to-current converter to the associated digital communication and control. The paper presents in depth the original digital quadrature signal generator and the output current generator with a high resistance. The other main blocks of the design use current practice specifications, since recent technological solutions proposed in the literature were found appropriate. The proposed signal generator circuit, characterized by a very low complexity, is analyzed in its capacity to produce multiple accurate signals up to 1 MHz in frequency. The precision output current source uses a modified current conveyor of type CCII with a high output resistance and low distortion. The output current frequency spectrum and linearity parameters obtained in the simulations are also described. The simulation results indicate a good linearity and high output resistance with an acceptable output voltage swing. The calculated performance parameters are validated with simulations, and future work for the prototype fabrication of the IC is outlined

Current-induced domain wall motion in magnetic nanowires with spatial variation

International Nuclear Information System (INIS)

Ieda, Jun'ichi; Sugishita, Hiroki; Maekawa, Sadamichi

2010-01-01

We model current-induced domain wall motion in magnetic nanowires with the variable width. Employing the collective coordinate method we trace the wall dynamics. The effect of the width modulation is implemented by spatial dependence of an effective magnetic field. The wall destination in the potential energy landscape due to the magnetic anisotropy and the spatial nonuniformity is obtained as a function of the current density. For a nanowire of a periodically modulated width, we identify three (pinned, nonlinear, and linear) current density regimes for current-induced wall motion. The threshold current densities depend on the pulse duration as well as the magnitude of wire modulation. In the nonlinear regime, application of ns order current pulses results in wall displacement which opposes or exceeds the prediction of the spin transfer mechanism. The finding explains stochastic nature of the domain wall displacement observed in recent experiments.

Influence of ambient humidity on the current delivered by air-vented ionization chambers revisited

International Nuclear Information System (INIS)

Poirier, Aurelie; Douysset, Guilhem

2006-01-01

The influence of ambient humidity on the current delivered by a vented ionization chamber has been re-investigated. A Nucletron 077.091 well-type chamber together with a 192 Ir HDR brachytherapy source was enclosed in a climatic test chamber and the current was recorded for various humidity values. Great care has been taken for the design of the experimental setup in order to obtain reliable measurements of currents and humidity values inside the chamber active volume. A ±0.35% linear variation of the measured currents has been observed over a common range of humidities. This result is larger than the expected variation. No formal explanation of such a discrepancy has been found yet, however the present results could lead to a set of recommendations

Influence of ambient humidity on the current delivered by air-vented ionization chambers revisited

Energy Technology Data Exchange (ETDEWEB)

Poirier, Aurelie; Douysset, Guilhem [Laboratoire National Henri Becquerel-LNE, CEA Saclay 91191 Gif-sur-Yvette (France)

2006-10-07

The influence of ambient humidity on the current delivered by a vented ionization chamber has been re-investigated. A Nucletron 077.091 well-type chamber together with a {sup 192}Ir HDR brachytherapy source was enclosed in a climatic test chamber and the current was recorded for various humidity values. Great care has been taken for the design of the experimental setup in order to obtain reliable measurements of currents and humidity values inside the chamber active volume. A {+-}0.35% linear variation of the measured currents has been observed over a common range of humidities. This result is larger than the expected variation. No formal explanation of such a discrepancy has been found yet, however the present results could lead to a set of recommendations.

Results obtained using the pellet charge exchange diagnostic on TFTR

International Nuclear Information System (INIS)

McChesney, J.M.; Fisher, R.K.; Parks, P.B.; Duong, H.H.; Mansfield, D.K.; Medley, S.S.; Roquemore, A.L.; Petrov, M.P.

1994-05-01

Experiments are underway on TFTR to measure the confined alpha particle distribution functions using small low-Z pellets injected into the plasma. Upon entering the plasma, the pellet ablates, forming a plasma ablation cloud, elongated in the magnetic field direction, that travels alongside the pellet. A small fraction of the fusion produced 3.5 MeV alpha particles incident on the cloud are converted to helium neutrals. By measuring the resultant helium neutrals escaping from the plasma by means of a mass and energy resolving charge exchange analyzer, the energy distribution of the alpha particles incident on the cloud can be inferred. Preliminary experiments to observe neutrals from the 100-1000 keV He tail produced during ICRF minority heating experiments were successful. However, no significant alpha particle signals have been observed during D-T operation on TFTR. The authors attribute this lack of signal to stochastic toroidal field ripple loss in the outer regions of the plasma. They are studying ways to improve the pellet penetration so that the pellet penetrates into the central regions of the plasma where ripple induced losses are small and the alpha population is high

GAMMA RADIATION INTERACTS WITH MELANIN TO ALTER ITS OXIDATION-REDUCTION POTENTIAL AND RESULTS IN ELECTRIC CURRENT PRODUCTION

Energy Technology Data Exchange (ETDEWEB)

Turick, C.; Ekechukwu, A.; Milliken, C.

2011-05-17

The presence of melanin pigments in organisms is implicated in radioprotection and in some cases, enhanced growth in the presence of high levels of ionizing radiation. An understanding of this phenomenon will be useful in the design of radioprotective materials. However, the protective mechanism of microbial melanin in ionizing radiation fields has not yet been elucidated. Here we demonstrate through the electrochemical techniques of chronoamperometry, chronopotentiometry and cyclic voltammetry that microbial melanin is continuously oxidized in the presence of gamma radiation. Our findings establish that ionizing radiation interacts with melanin to alter its oxidation-reduction potential. Sustained oxidation resulted in electric current production and was most pronounced in the presence of a reductant, which extended the redox cycling capacity of melanin. This work is the first to establish that gamma radiation alters the oxidation-reduction behavior of melanin, resulting in electric current production. The significance of the work is that it provides the first step in understanding the initial interactions between melanin and ionizing radiation taking place and offers some insight for production of biomimetic radioprotective materials.

Analytical form of current-voltage characteristic of parallel-plane, cylindrical and spherical ionization chambers with homogeneous ionization

Energy Technology Data Exchange (ETDEWEB)

Stoyanov, D G [Faculty of Engineering and Pedagogy in Sliven, Technical University of Sofia, 59, Bourgasko Shaussee Blvd, 8800 Sliven (Bulgaria)

2007-11-15

The elementary processes taking place in the formation of charged particles and their flow in parallel-plane, cylindrical and spherical geometry cases of ionization chamber are considered. On the basis of particles and charges balance a differential equation describing the distribution of current densities in the ionization chamber volume is obtained. As a result of the differential equation solution an analytical form of the current-voltage characteristic of an ionization chamber with homogeneous ionization is obtained. For the parallel-plane case comparision with experimental data is performed.

Analytical form of current-voltage characteristic of parallel-plane, cylindrical and spherical ionization chambers with homogeneous ionization

International Nuclear Information System (INIS)

Stoyanov, D G

2007-01-01

The elementary processes taking place in the formation of charged particles and their flow in parallel-plane, cylindrical and spherical geometry cases of ionization chamber are considered. On the basis of particles and charges balance a differential equation describing the distribution of current densities in the ionization chamber volume is obtained. As a result of the differential equation solution an analytical form of the current-voltage characteristic of an ionization chamber with homogeneous ionization is obtained. For the parallel-plane case comparision with experimental data is performed

Charged current deep-inelastic scattering at three loops

International Nuclear Information System (INIS)

Moch, S.; Rogal, M.

2007-04-01

We derive for deep-inelastic neutrino(ν)-proton(P) scattering in the combination νP- anti νP the perturbative QCD corrections to three loops for the charged current structure functions F 2 , F L and F 3 . In leading twist approximation we calculate the first five odd-integer Mellin moments in the case of F 2 and F L and the first five even-integer moments in the case of F 3 . As a new result we obtain the coefficient functions to O(α 3 s ) while the corresponding anomalous dimensions agree with known results in the literature. (orig.)

Automated eddy current signal processing: operation between declarative and procedural programming

International Nuclear Information System (INIS)

Zorgati, R.; Georgel, B.; Duvaut, P.; Doligez, T.; Garreau, D.

1993-09-01

In this paper we present the problem of cooperation between numerical and symbolical programming. This cooperation enables an efficient substitution of some human based decisions. This approach is applied to Eddy current testing of steam generator tubes. We illustrate our purpose with results obtained with the mock-up Extraction. (authors). 1 fig., 5 refs

Physics issues of high bootstrap current tokamaks

International Nuclear Information System (INIS)

Ozeki, T.; Azumi, M.; Ishii, Y.

1997-01-01

Physics issues of a tokamak plasma with a hollow current profile produced by a large bootstrap current are discussed based on experiments in JT-60U. An internal transport barrier for both ions and electrons was obtained just inside the radius of zero magnetic shear in JT-60U. Analysis of the toroidal ITG microinstability by toroidal particle simulation shows that weak and negative shear reduces the toroidal coupling and suppresses the ITG mode. A hard beta limit was observed in JT-60U negative shear experiments. Ideal MHD mode analysis shows that the n = 1 pressure-driven kink mode is a plausible candidate. One of the methods to improve the beta limit against the kink mode is to widen the negative shear region, which can induce a broader pressure profile resulting in a higher beta limit. The TAE mode for the hollow current profile is less unstable than that for the monotonic current profile. The reason is that the continuum gaps near the zero shear region are not aligned when the radius of q min is close to the region of high ∇n e . Finally, a method for stable start-up for a plasma with a hollow current profile is describe, and stable sustainment of a steady-state plasma with high bootstrap current is discussed. (Author)

Microscopic models for bridging electrostatics and currents

Science.gov (United States)

Borghi, L.; DeAmbrosis, A.; Mascheretti, P.

2007-03-01

A teaching sequence based on the use of microscopic models to link electrostatic phenomena with direct currents is presented. The sequence, devised for high school students, was designed after initial work carried out with student teachers attending a school of specialization for teaching physics at high school, at the University of Pavia. The results obtained with them are briefly presented, because they directed our steps for the development of the teaching sequence. For both the design of the experiments and their interpretation, we drew inspiration from the original works of Alessandro Volta; in addition, a structural model based on the particular role of electrons as elementary charges both in electrostatic phenomena and in currents was proposed. The teaching sequence starts from experiments on charging objects by rubbing and by induction, and engages students in constructing microscopic models to interpret their observations. By using these models and by closely examining the ideas of tension and capacitance, the students acknowledge that a charging (or discharging) process is due to the motion of electrons that, albeit for short time intervals, represent a current. Finally, they are made to see that the same happens in transients of direct current circuits.

HIRFL-SSC trim coil currents calculation by conjugate gradients method

International Nuclear Information System (INIS)

Liu, W.

2005-01-01

For accelerating different kinds of ions to various energies, the HIRFL-SSC should form the corresponding isochronous magnetic field by its main coil and trim coils. Previously, there were errors in fitting the theoretical isochronous magnetic field in the small radius region, which led to some operation difficulties for ion acceleration in the inject region. After further investigation of the restrictive condition of the maximum current limitation, the trim coil currents for fitting the theoretical isochronous magnetic field were recalculated by the conjugate gradients method. Better results were obtained in the operation of HIRFL-SSC. This article introduces the procedure to calculate the trim coil currents. The calculation method of conjugate gradients is introduced and the fitting error is analysed. (author)

Recent results from the Large Hadron Collider

CERN Document Server

Alcaraz Maestre, J

2013-01-01

We present an overview of the physics results obtained by experiments at the Large Hadron Collider (LHC) in 2009–2010, for an integrated luminosity of L ≈ 40 pb$^{−1}$ , collected mostly at a centre-of-mass energy of √ s = 7 TeV. After an introduction to the physics environment at the LHC and the current performance of the accelerator and detectors, we will discuss quantum chro- modynamics and B-physics analyses, W and Z production, the first results in the top sector, and searches for new physics, with particular emphasis on su- persymmetry and Higgs studies. While most of the presented results are in remarkable agreement with Standard Model predictions, the excellent perfor- mance of the LHC machine and experiments, the prompt analysis of all data within just a few months after the end of data taking, and the high quality of the results obtained constitute an encouraging step towards unique measurements and exciting discoveries in the 2011–2012 period and beyond.

On the accuracy of current TCAD hot carrier injection models in nanoscale devices

Science.gov (United States)

Zaka, Alban; Rafhay, Quentin; Iellina, Matteo; Palestri, Pierpaolo; Clerc, Raphaël; Rideau, Denis; Garetto, Davide; Dornel, Erwan; Singer, Julien; Pananakakis, Georges; Tavernier, Clément; Jaouen, Hervé

2010-12-01

In this work, the hot electron injection models presently available for technology support have been investigated within the context of the development of advanced embedded non-volatile memories. The distribution functions obtained by these models (namely the Fiegna Model - FM [1], the Lucky Electron Model - LEM [2] and the recently implemented Spherical Harmonics Expansion of the Boltzman's Transport Equation - SHE [3]), have been systematically compared to rigorous Monte Carlo (MC) results [4], both in homogeneous and device conditions. Gate-to-drain current ratio and gate current density simulation has also been benchmarked in device simulations. Results indicate that local models such as FM, can partially capture the channel hot electron injection, at the price of model parameter adjustments. Moreover, at least in the device and field condition considered in this work, an overall better agreement with MC simulations has been obtained using the 1st order SHE, even without any particular fitting procedure. Extending the results presented in [3] by exploring shorter gate lengths and addressing the floating gate voltage dependence of the gate current, this work shows that the SHE method could contribute to bridge the gap between the rigorous but time consuming MC method and less rigorous but suitable TCAD local models.

Comprehensive assessment of energy systems: approach and current results of the Swiss activities

International Nuclear Information System (INIS)

Hirschberg, S.; Dones, R.; Kypreos, S.

1994-01-01

This paper provides an overview of the approaches used and results obtained to this date within the Swiss Project GaBE on ''Comprehensive Assessment of Energy Systems''. Based on the ''cradle to grave'' approach detailed environmental inventories for major fuel cycles have been generated. In comparison to earlier studies a very broad spectrum of resources and air and water pollutants has been covered. Also non-energetic resources such as land depreciation have been considered. Numerous examples of evaluations are provided in the paper, including comparisons of greenhouse gas emissions, land use, radiation and wastes, and illustrating the impact of consideration of full energy chains. In the part concerning severe accidents some evaluations based on the database established as the Paul Scherrer Institute are presented as well as the estimated contribution of hypothetical severe accidents to the external costs associated with a specific Swiss nuclear power plant. Results of applications of the large scale energy-economy model MARKAL to the Swiss energy system and greenhouse gas scenarios are described. This includes cost-optimal contributions of different technologies to reduce CO 2 emissions, and trade-offs on the national and international level. Finally, the content of other GaBE activities either being in progress or planned is provided. (orig.)

Charge Transport in Spiro-OMeTAD Investigated through Space-Charge-Limited Current Measurements

Science.gov (United States)

Röhr, Jason A.; Shi, Xingyuan; Haque, Saif A.; Kirchartz, Thomas; Nelson, Jenny

2018-04-01

Extracting charge-carrier mobilities for organic semiconductors from space-charge-limited conduction measurements is complicated in practice by nonideal factors such as trapping in defects and injection barriers. Here, we show that by allowing the bandlike charge-carrier mobility, trap characteristics, injection barrier heights, and the shunt resistance to vary in a multiple-trapping drift-diffusion model, a numerical fit can be obtained to the entire current density-voltage curve from experimental space-charge-limited current measurements on both symmetric and asymmetric 2 ,2',7 ,7' -tetrakis(N ,N -di-4-methoxyphenylamine)-9 ,9' -spirobifluorene (spiro-OMeTAD) single-carrier devices. This approach yields a bandlike mobility that is more than an order of magnitude higher than the effective mobility obtained using analytical approximations, such as the Mott-Gurney law and the moving-electrode equation. It is also shown that where these analytical approximations require a temperature-dependent effective mobility to achieve fits, the numerical model can yield a temperature-, electric-field-, and charge-carrier-density-independent mobility. Finally, we present an analytical model describing trap-limited current flow through a semiconductor in a symmetric single-carrier device. We compare the obtained charge-carrier mobility and trap characteristics from this analytical model to the results from the numerical model, showing excellent agreement. This work shows the importance of accounting for traps and injection barriers explicitly when analyzing current density-voltage curves from space-charge-limited current measurements.

Current control of superconducting coils for fusion experimental facility

International Nuclear Information System (INIS)

Ise, T.; Etou, D.; Chikaraishi, H.; Takami, S.; Inoue, T.

2003-01-01

The LHD (Large Helical Device) has twelve superconducting coils and six dc power supplies, and following specifications are required for its control system; each coil current must be controlled independently, the steady state control error is less than 0.01% of the reference value, the current settling time for 0.1% of control error is less than 1 second, and the control system must be robust against turbulence caused by appearance and disappearance of the plasma, parameter errors and external electro-magnetic noises. In this paper, the design and test results of the coil current control system for the LHD are described. The good response and robustness are in the relation of trade off each other. H-infinity controller is one of schemes to guarantee robustness for stability. However, the independent responses of six coils were impossible by the H-infinity controller only. To resolve this problem, we applied a feed-forward control with the H-infinity control. Moreover, the advanced design method of H-infinity controller using μ-synthesis was applied to guarantee the control performance in the whole operating condition. As a result, good control results were obtained by experiments. (author)

Accurate characterization of organic thin film transistors in the presence of gate leakage current

Directory of Open Access Journals (Sweden)

Vinay K. Singh

2011-12-01

Full Text Available The presence of gate leakage through polymer dielectric in organic thin film transistors (OTFT prevents accurate estimation of transistor characteristics especially in subthreshold regime. To mitigate the impact of gate leakage on transfer characteristics and allow accurate estimation of mobility, subthreshold slope and on/off current ratio, a measurement technique involving simultaneous sweep of both gate and drain voltages is proposed. Two dimensional numerical device simulation is used to illustrate the validity of the proposed technique. Experimental results obtained with Pentacene/PMMA OTFT with significant gate leakage show a low on/off current ratio of ∼ 102 and subthreshold is 10 V/decade obtained using conventional measurement technique. The proposed technique reveals that channel on/off current ratio is more than two orders of magnitude higher at ∼104 and subthreshold slope is 4.5 V/decade.

Application of digital PWM technology in current transducers

International Nuclear Information System (INIS)

Liu Huifang; Hu Zhimin; Li Rui

2012-01-01

With the development of DSP technology and mature use of PID technology,, a new program for DC or AC signal measurement is proposed. Combined with the DSP chip timer module and PID algorithm, PWM signals are generated to control the feedback circuit for the compensation current. Finally the measured current value can be obtained according to the ampere-turns compensation current and the measured current. Studies have shown that this technology enables new current transducers have high stability. (authors)

Research on the correlation between corona current spectrum and audible noise spectrum of HVDC transmission line

Science.gov (United States)

Liu, Yingyi; Zhou, Lijuan; Liu, Yuanqing; Yuan, Haiwen; Ji, Liang

2017-11-01

Audible noise is closely related to corona current on a high voltage direct current (HVDC) transmission line. In this paper, we measured a large amount of audible noise and corona current waveforms simultaneously based on the largest outdoor HVDC corona cage all over the world. By analyzing the experimental data, the related statistical regularities between a corona current spectrum and an audible noise spectrum were obtained. Furthermore, the generation mechanism of audible noise was analyzed theoretically, and the related mathematical expression between the audible noise spectrum and the corona current spectrum, which is suitable for all of these measuring points in the space, has been established based on the electro-acoustic conversion theory. Finally, combined with the obtained mathematical relation, the internal reasons for these statistical regularities appearing in measured corona current and audible noise data were explained. The results of this paper not only present the statistical association regularities between the corona current spectrum and the audible noise spectrum on a HVDC transmission line, but also reveal the inherent reasons of these associated rules.

Current control by ECCD for W7-X

International Nuclear Information System (INIS)

Turkin, Yu.; Maassberg, H.; Beidler, C.D.; Geiger, J.; Marushchenko, N.B.

2005-01-01

One of the optimization criteria for the stellarator W7-X is the minimization of the bootstrap current. The plasma current changes the magnetic configuration, especially near the plasma edge, where X-points and islands are located. It was shown that the plasma parameter distributions in the divertor region and the particle and energy depositions on the divertor plates depend strongly on the island geometry. An estimation of the tolerable plasma current obtained from the shift of the island structure close to the target plates shows that the plasma current should be controlled within a range of about 10 kA. The bootstrap current even for the standard configuration can easily exceed this value. The W7-X is not equipped with an Ohmic transformer, so the only means for compensating this current is electron cyclotron current drive (ECCD) and/or neutral beam current drive (NBCD). In this report we study the compensation of residual bootstrap current by using ECCD. To model the control of the toroidal current we use a predictive 1D transport code, which is under development. For evaluation of the bootstrap current and neoclassical transport coefficients we use results from an international collaboration on neoclassical transport in stellarators. Power deposition and current drive profiles due to electron cyclotron resonance heating are calculated by a new ray tracing code. The modeling showed that the loop voltage induced by ECCD leads to a redistribution of the current density with the diffusion time of about two seconds. The relaxation time of the total current is much longer than this time - for a typical ECRH-plasma the total toroidal current reaches steady state after several L/R-time that is about hundreds of seconds. In order to keep current in an acceptable range and to avoid long relaxation times we propose Feed-forward or Predictive control using ECCD as actuator, the steps are as follows: - calculate the bootstrap current distribution using measured plasma

Circulation-based Modeling of Gravity Currents

Science.gov (United States)

Meiburg, E. H.; Borden, Z.

2013-05-01

Atmospheric and oceanic flows driven by predominantly horizontal density differences, such as sea breezes, thunderstorm outflows, powder snow avalanches, and turbidity currents, are frequently modeled as gravity currents. Efforts to develop simplified models of such currents date back to von Karman (1940), who considered a two-dimensional gravity current in an inviscid, irrotational and infinitely deep ambient. Benjamin (1968) presented an alternative model, focusing on the inviscid, irrotational flow past a gravity current in a finite-depth channel. More recently, Shin et al. (2004) proposed a model for gravity currents generated by partial-depth lock releases, considering a control volume that encompasses both fronts. All of the above models, in addition to the conservation of mass and horizontal momentum, invoke Bernoulli's law along some specific streamline in the flow field, in order to obtain a closed system of equations that can be solved for the front velocity as function of the current height. More recent computational investigations based on the Navier-Stokes equations, on the other hand, reproduce the dynamics of gravity currents based on the conservation of mass and momentum alone. We propose that it should therefore be possible to formulate a fundamental gravity current model without invoking Bernoulli's law. The talk will show that the front velocity of gravity currents can indeed be predicted as a function of their height from mass and momentum considerations alone, by considering the evolution of interfacial vorticity. This approach does not require information on the pressure field and therefore avoids the need for an energy closure argument such as those invoked by the earlier models. Predictions by the new theory are shown to be in close agreement with direct numerical simulation results. References Von Karman, T. 1940 The engineer grapples with nonlinear problems, Bull. Am. Math Soc. 46, 615-683. Benjamin, T.B. 1968 Gravity currents and related

A two dimensional model of undertow current over mud bed

International Nuclear Information System (INIS)

Mir Hammadul Azam; Abdul Aziz Ibrahim; Noraieni Hj, Mokhtar

1996-01-01

Coastal wave-current dynamics often causes severe erosion and this activity is more prominent within the surf zone. Turbulence generated by breaking wave is a complex phenomena and the degree of complexity increases to a higher degree when it happens over mud bed. A better understanding on wave and current is necessary to enrich the engineering hand to facilitate any coastal development work. Since physical model has certain deficiencies, such as high cost and scaling problem, the need for developing numerical models in such cases is significant. A time averaged two dimensional model has been developed to simulate the undertow over mud bed. A turbulent energy model also included which considers only the vertical variation of mixing length. Production of turbulent kinetic energy in the surf zone has been calculated from an hydraulic jump analogy. The result obtained shows an insignificant vertical variation of current. Further research is needed involving laboratory and field works to get sufficient data for comparing the model results

Application of Oversampling to obtain the MTF of Digital Radiology Equipment.

Science.gov (United States)

Narváez, M.; Graffigna, J. P.; Gómez, M. E.; Romo, R.

2016-04-01

Within the objectives of theproject Medical Image Processing for QualityAssessment ofX Ray Imaging, the present research work is aimed at developinga phantomX ray image and itsassociated processing algorithms in order to evaluatethe image quality rendered by digital X ray equipment. These tools are used to measure various image parameters, among which spatial resolution shows afundamental property that can be characterized by the Modulation Transfer Function (MTF)of an imaging system [1]. After performing a thorough literature surveyon imaging quality control in digital X film in Argentine and international publications, it was decided to adopt for this work the Norm IEC 62220 1:2003 that recommends using an image edge as a testingmethod. In order to obtain the characterizing MTF, a protocol was designedfor unifying the conditions under which the images are acquired for later evaluation. The protocol implied acquiring a radiography image by means of a specific referential technique, i.e. referred either to voltage, current, time, distance focus plate (/film?) distance, or other referential parameter, and to interpret the image through a system of computed radiology or direct digital radiology. The contribution of the work stems from the fact that, even though the traditional way of evaluating an X film image quality has relied mostly on subjective methods, this work presents an objective evaluative toolfor the images obtained with a givenequipment, followed by a contrastive analysis with the renderings from other X filmimaging sets.Once the images were obtained, specific calculations were carried out. Though there exist some methods based on the subjective evaluation of the quality of image, this work offers an objective evaluation of the equipment under study. Finally, we present the results obtained on different equipment.

Application of Oversampling to obtain the MTF of Digital Radiology Equipment

International Nuclear Information System (INIS)

Narváez, M.; Graffigna, J. P.; Gómez, M. E.; Romo, R.

2016-01-01

Within the objectives of theproject Medical Image Processing for QualityAssessment ofX Ray Imaging, the present research work is aimed at developinga phantomX ray image and itsassociated processing algorithms in order to evaluatethe image quality rendered by digital X ray equipment. These tools are used to measure various image parameters, among which spatial resolution shows afundamental property that can be characterized by the Modulation Transfer Function (MTF)of an imaging system [1]. After performing a thorough literature surveyon imaging quality control in digital X film in Argentine and international publications, it was decided to adopt for this work the Norm IEC 62220 1:2003 that recommends using an image edge as a testingmethod. In order to obtain the characterizing MTF, a protocol was designedfor unifying the conditions under which the images are acquired for later evaluation. The protocol implied acquiring a radiography image by means of a specific referential technique, i.e. referred either to voltage, current, time, distance focus plate (/film?) distance, or other referential parameter, and to interpret the image through a system of computed radiology or direct digital radiology. The contribution of the work stems from the fact that, even though the traditional way of evaluating an X film image quality has relied mostly on subjective methods, this work presents an objective evaluative toolfor the images obtained with a givenequipment, followed by a contrastive analysis with the renderings from other X filmimaging sets.Once the images were obtained, specific calculations were carried out. Though there exist some methods based on the subjective evaluation of the quality of image, this work offers an objective evaluation of the equipment under study. Finally, we present the results obtained on different equipment. (paper)

Neutron transport assembly calculation with non-zero net current boundary condition

International Nuclear Information System (INIS)

Jo, Chang Keun

1993-02-01

is then performed by CASMO-3M with the inhomogeneous source. The results of the benchmark problems show that the relative errors of mesh wise fluxed are negligible. It is thus verified that CASMO-3M can perform assembly calculation with inhomogeneous sources, i.e., non-zero net current boundary conditions. The two sets of the homogenized group constants obtained by the assembly calculation with (1) zero net current boundary condition (i.e., CASMO-3) and (2) non-zero net current boundary condition (i.e., CASMO-3M) show significant differences. Thus, it will be worthwhile to evaluate the global effects (e.g., core multiplication factor and assembly power distribution of the core) of the homogenized group constants obtained with the non-zero net current boundary condition by CASMO-3M

Purification of alcohol obtained from molasses

Energy Technology Data Exchange (ETDEWEB)

Visnevskaya, G L; Egorov, A S; Sokol' skaya, E V

1960-01-01

A study of the composition of alcohol liquids on different plates of a fractionation column of indirect action during purification of alcohol obtained from normal and defective molasses, and from starch raw material, showed that there were two local strength minima in the lower part of the column and on the plates (adjacent and feed). Aldehydes behaved as a typical head impurity; a noticeable increase in their concentration occurred only on the highest plates in the fractionation column. In the zone of the column containing liquids of a strength of 86 to 94% alcohol by weight a sharply pronounced local maximum of ester accumulation were observed, provisionally designated as intermediate, whose presence is apparently one of the causes of the specific sharp taste of alcohol obtained from molasses. These esters hinder the obtaining of high-grade alcohols which are standard in respect to ester content and oxidizability test. Reduction with 0.05N KMnO/sub 4/ occurs most rapidly with alcohol liquids in the zone of ester accumulation; purification of alcohols obtained from grain and potato raw material resulted in no zones of ester accumulation in the column.

Gold Nanoparticles Obtained by Bio-precipitation from Gold(III) Solutions

International Nuclear Information System (INIS)

Gardea-Torresdey, J.L.; Tiemann, K.J.; Gamez, G.; Dokken, K.; Tehuacanero, S.; Jose-Yacaman, M.

1999-01-01

The use of metal nanoparticles has shown to be very important in recent industrial applications. Currently gold nanoparticles are being produced by physical methods such as evaporation. Biological processes may be an alternative to physical methods for the production of gold nanoparticles. Alfalfa biomass has shown to be effective at passively binding and reducing gold from solutions containing gold(III) ions and resulting in the formation of gold(0) nanoparticles. High resolution microscopy has shown that five different types of gold particles are present after reaction with gold(III) ions with alfalfa biomass. These particles include: fcc tetrahedral, hexagonal platelet, icosahedral multiple twinned, decahedral multiple twinned, and irregular shaped particles. Further analysis on the frequency of distribution has shown that icosahedral and irregular particles are more frequently formed. In addition, the larger particles observed may be formed through the coalescence of smaller particles. Through modification of the chemical parameters, more uniform particle size distribution may be obtained by the alfalfa bio-reduction of gold(III) from solution

A Novel Programmable CMOS Fuzzifiers Using Voltage-to-Current Converter Circuit

Directory of Open Access Journals (Sweden)

K. P. Abdulla

2012-01-01

Full Text Available This paper presents a new voltage-input, current-output programmable membership function generator circuit (MFC using CMOS technology. It employs a voltage-to-current converter to provide the required current bias for the membership function circuit. The proposed MFC has several advantageous features. This MFC can be reconfigured to perform triangular, trapezoidal, S-shape, Z-Shape, and Gaussian membership forms. This membership function can be programmed in terms of its width, slope, and its center locations in its universe of discourses. The easily adjustable characteristics of the proposed circuit and its accuracy make it suitable for embedded system and industrial control applications. The proposed MFC is designed using the spice software, and simulation results are obtained.

Current and cumulative night shift work and subclinical atherosclerosis: results of the Gutenberg Health Study.

Science.gov (United States)

Jankowiak, S; Backé, E; Liebers, F; Schulz, A; Hegewald, J; Garthus-Niegel, S; Nübling, M; Blankenberg, S; Pfeiffer, N; Lackner, K J; Beutel, M; Blettner, M; Münzel, T; Wild, P S; Seidler, A; Letzel, S; Latza, U

2016-11-01

The study examines the association between exposure to current and cumulative night shift work and subclinical parameters of atherosclerosis. Participants of a population-based cohort study (the Gutenberg Health Study, N = 15,010) aged 35-64 years were examined at baseline (2007-2012). Investigations included measurements of arterial stiffness, vascular function [reactive hyperaemia (RH) index], and intima media thickness (IMT). Also, a complete job history (including up to 15 periods), occupational exposures, a variety of lifestyle, and dispositional variables were enquired. Night shift work was performed by 1071 out of 8065 currently employed individuals. The strongest association after adjustment for age, sex, job complexity level, being a manager, overtime work, and noise appeared for more than 660 night shifts within the last 10 years and a significantly increased arterial stiffness of 0.33 m/s. This reflects a 4 % flow velocity increase for individuals with more than 660 night shifts compared to non-night workers. Regarding the entire professional life, night shift workers showed a significantly decreased vascular function by -0.054 RH index points by using the same adjustment. IMT values did not differ statistically from non-night workers. Lifestyle and dispositional factors showed an influence on all used subclinical atherosclerosis parameters. The cross-sectional results demonstrate an association between night work and detrimental changes in the atherosclerotic process. The association is more pronounced with more years in night shift and is partly explained by lifestyle and dispositional factors. Longitudinal analyses are necessary to confirm the results.

Biomonitoring of heavy metal deposition in the south Ural region: some preliminary results obtained by nuclear and related techniques

International Nuclear Information System (INIS)

Frontas'eva, M.V.; Steinnes, E.; Lyapunov, S.M.; Cherchintsev, V.D.; Smirnov, L.I.

1999-01-01

The first results are reported from the analysis of feather mosses used to study heavy metal atmospheric deposition in the vicinity of Magnitogorsk, the center of the steel industry in Russia. Moss samples collected at sites 30 km to the north-west of the industry were analyzed by instrumental neutron activation analysis using epithermal neutrons (ENAA), Results for a total of 38 elements are reported, including Pb, Cd, and Cu determined by atomic absorption spectroscopy (AAS). The element concentrations in moss samples from this work are compared with relevant literature data for strongly polluted areas in Central and Northern Europe and background values from Norway obtained by the same biomonitoring technique. The concentrations of Sb in the examined area are the highest ever reported for mosses, and also levels of Fe, Cr, and V are found to be particularly high. A scanning electron microscope connected to an XRF analyzer (SEM-XRF) was used to examine the surface of the moss samples. Photographs of identified iron spherules along with other aerosol particles made at magnification of 3500 to 5000 times and corresponding XRF analyses verifying the nature of typical particles are presented

Radioimmunotherapy for malignant diseases. Current contributions and future options

International Nuclear Information System (INIS)

Mahe, M.A.; Chatal, J.F.

1995-01-01

Radioimmunotherapy is based on the use of radioactive agents (iodine 131, yttrium 90), murine-derived monoclonal antibodies and specific tumour-related membrane antigens. This new treatment modality was applied in 800 patients with different types of malignant tumours which had not responded to traditional therapy. Among the haematologic tumours, the most promising results were obtained in B phenotype non-Hodgkin lymphoma. More modest results were obtained for solid tumours although good results were observed after intraperitoneal administration in patients with cancer of the ovary. The main side effects are acute reversible anaphylactic shock, haematologic toxicity and development of anti-murine human antibodies. Several methods are currently under study to increase irradiation dose delivered at the tumoural site since less than 1% of the injected radioactive dose is absorbed by tumoural cells. Several clinical studies are to be conducted in France, particularly for malignant non-Hodgkin lymphoma and cancer of the ovary. (authors). 31 refs

Zero current measurements using the Rogowski coil

International Nuclear Information System (INIS)

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)

Modulational instability development and current drive

International Nuclear Information System (INIS)

Popel, S.I.; Vladimirov, S.V.; Tsytovich, V.N.

1992-01-01

Recently many investigations on current driven by lower-hybrid (LH) waves in a plasma of toroidal nuclear fusion installations are carried out. Usually a theoretical approach taking into account quasilinear and binary collisions effects is used to describe current drive. However a problem of comparison of the results obtained with the aid of the above theoretical approach and experimental data takes place. Namely the experimentally observed currents driven by LH waves is two-three orders of magnitude larger than those calculated. The above discrepancy between theory and experiment is related with the existence of the so-called ''spectral gap'', that is the gap between the parallel phase velocities of LH waves ω/k || (where ω, k || are LH wave frequency and a component of wavenumber k parallel to the external magnetic field) which are necessary for effective Landau damping of LH waves (i.e. velocities as high as several electron thermal velocities) and the lowest parallel phase velocity in the injected LH wave spectrum. Experimentally observed current drive may be explained if one accounts for filling of the ''spectral gap'' by LH waves. Some nonlinear effects have been drawn in current drive description to explain the ''spectral gap'' filling by LH waves. However the LH wave modulational instability (MI) effect has not been considered yet in application to current drive description. The aim of this paper is to investigate this MI influence. We shall show that for sufficiently intensive pump level of LH wave the MI can lead to ''spectral gap'' filling. (author) 4 refs

Interpretation of secondary electron images obtained using a low vacuum SEM

International Nuclear Information System (INIS)

Toth, M.; Thiel, B.L.; Donald, A.M.

2003-01-01

Charging of insulators in a variable pressure environment was investigated in the context of secondary electron (SE) image formation. Sample charging and ionized gas molecules present in a low vacuum specimen chamber can give rise to SE image contrast. 'Charge-induced' SE contrast reflects lateral variations in the charge state of a sample caused by electron irradiation during and prior to image acquisition. This contrast corresponds to SE emission current alterations produced by sub-surface charge deposited by the electron beam. 'Ion-induced' contrast results from spatial inhomogeneities in the extent of SE signal inhibition caused by ions in the gaseous environment of a low vacuum scanning electron microscope (SEM). The inhomogeneities are caused by ion focusing onto regions of a sample that correspond to local minima in the magnitude of the surface potential (generated by sub-surface trapped charge), or topographic asperities. The two types of contrast exhibit characteristic dependencies on microscope operating parameters such as scan speed, beam current, gas pressure, detector bias and working distance. These dependencies, explained in terms of the behavior of the gaseous environment and sample charging, can serve as a basis for a correct interpretation of SE images obtained using a low vacuum SEM

Using Internet Search Engines to Obtain Medical Information: A Comparative Study

Science.gov (United States)

Wang, Liupu; Wang, Juexin; Wang, Michael; Li, Yong; Liang, Yanchun

2012-01-01

Background The Internet has become one of the most important means to obtain health and medical information. It is often the first step in checking for basic information about a disease and its treatment. The search results are often useful to general users. Various search engines such as Google, Yahoo!, Bing, and Ask.com can play an important role in obtaining medical information for both medical professionals and lay people. However, the usability and effectiveness of various search engines for medical information have not been comprehensively compared and evaluated. Objective To compare major Internet search engines in their usability of obtaining medical and health information. Methods We applied usability testing as a software engineering technique and a standard industry practice to compare the four major search engines (Google, Yahoo!, Bing, and Ask.com) in obtaining health and medical information. For this purpose, we searched the keyword breast cancer in Google, Yahoo!, Bing, and Ask.com and saved the results of the top 200 links from each search engine. We combined nonredundant links from the four search engines and gave them to volunteer users in an alphabetical order. The volunteer users evaluated the websites and scored each website from 0 to 10 (lowest to highest) based on the usefulness of the content relevant to breast cancer. A medical expert identified six well-known websites related to breast cancer in advance as standards. We also used five keywords associated with breast cancer defined in the latest release of Systematized Nomenclature of Medicine-Clinical Terms (SNOMED CT) and analyzed their occurrence in the websites. Results Each search engine provided rich information related to breast cancer in the search results. All six standard websites were among the top 30 in search results of all four search engines. Google had the best search validity (in terms of whether a website could be opened), followed by Bing, Ask.com, and Yahoo!. The search

Obtaining zircaloy powder through hydriding

International Nuclear Information System (INIS)

Dupim, Ivaldete da Silva; Moreira, Joao M.L.

2009-01-01

Zirconium alloys are good options for the metal matrix in dispersion fuels for power reactors due to their low thermal neutron absorption cross-section, good corrosion resistance, good mechanical strength and high thermal conductivity. A necessary step for obtaining such fuels is producing Zr alloy powder for the metal matrix composite material. This article presents results from the Zircaloy-4 hydrogenation tests with the purpose to embrittle the alloy as a first step for comminuting. Several hydrogenation tests were performed and studied through thermogravimetric analysis. They included H 2 pressures of 25 and 50 kPa and temperatures ranging between from 20 to 670 deg C. X-ray diffraction analysis showed in the hydrogenated samples the predominant presence of ZrH 2 and some ZrO 2 . Some kinetics parameters for the Zircaloy-4 hydrogenation reaction were obtained: the time required to reach the equilibrium state at the dwell temperature was about 100 minutes; the hydrogenation rate during the heating process from 20 to 670 deg C was about 21 mg/h, and at constant temperature of 670 deg C, the hydride rate was about 1.15 mg/h. The hydrogenation rate is largest during the heating process and most of it occurs during this period. After hydrogenated, the samples could easily be comminuted indicating that this is a possible technology to obtain Zircaloy powder. The results show that only few minutes of hydrogenation are necessary to reach the hydride levels required for comminuting the Zircaloy. The final hydride stoichiometry was between 2.7 and 2.8 H for each Zr atom in the sample (author)

Organoclays obtaining starting up of clays sodium

International Nuclear Information System (INIS)

Silva, M.M. da; Mota, M.F.; Oliveira, G.C. de; Rodrigues, M.G.F.

2012-01-01

Clays have several applications in many areas of fields of technology, however, modification of these materials using organic compounds can be performed to obtain further hydrophobic materials, for applications in the adsorption of organic pollutants. This study aimed to analyze the effects of modifying two clays using sodium quaternary ammonium surfactants through ion exchange reaction process, in obtaining organoclays. The samples with sodium and organoclays were characterized by the techniques of X-ray diffraction (XRD), Infrared Spectroscopy in the region (IV), Gravimetric and Differential Thermal Analysis (DTA / TG) and organic adsorption tests. The results show that the process of obtaining organoclay is efficient, and materials have the potential for future applications in removing organic contaminants. (author)

Rotating gravity currents. Part 1. Energy loss theory

Science.gov (United States)

Martin, J. R.; Lane-Serff, G. F.

2005-01-01

A comprehensive energy loss theory for gravity currents in rotating rectangular channels is presented. The model is an extension of the non-rotating energy loss theory of Benjamin (J. Fluid Mech. vol. 31, 1968, p. 209) and the steady-state dissipationless theory of rotating gravity currents of Hacker (PhD thesis, 1996). The theory assumes the fluid is inviscid, there is no shear within the current, and the Boussinesq approximation is made. Dissipation is introduced using a simple method. A head loss term is introduced into the Bernoulli equation and it is assumed that the energy loss is uniform across the stream. Conservation of momentum, volume flux and potential vorticity between upstream and downstream locations is then considered. By allowing for energy dissipation, results are obtained for channels of arbitrary depth and width (relative to the current). The results match those from earlier workers in the two limits of (i) zero rotation (but including dissipation) and (ii) zero dissipation (but including rotation). Three types of flow are identified as the effect of rotation increases, characterized in terms of the location of the outcropping interface between the gravity current and the ambient fluid on the channel boundaries. The parameters for transitions between these cases are quantified, as is the detailed behaviour of the flow in all cases. In particular, the speed of the current can be predicted for any given channel depth and width. As the channel depth increases, the predicted Froude number tends to surd 2, as for non-rotating flows.

Geopolymer obtained from coal ash

International Nuclear Information System (INIS)

Conte, V.; Bissari, E.S.; Uggioni, E.; Bernardin, A.M.

2011-01-01

Geopolymers are three-dimensional alumino silicates that can be rapidly formed at low temperature from naturally occurring aluminosilicates with a structure similar to zeolites. In this work coal ash (Tractebel Energy) was used as source of aluminosilicate according a full factorial design in eight formulations with three factors (hydroxide type and concentration and temperature) and two-levels. The ash was dried and hydroxide was added according type and concentration. The geopolymer was poured into cylindrical molds, cured (14 days) and subjected to compression test. The coal ash from power plants belongs to the Si-Al system and thus can easily form geopolymers. The compression tests showed that it is possible to obtain samples with strength comparable to conventional Portland cement. As a result, temperature and molarity are the main factors affecting the compressive strength of the obtained geopolymer. (author)

Current fluctuations in quantum absorption refrigerators

Science.gov (United States)

Segal, Dvira

2018-05-01

Absorption refrigerators transfer thermal energy from a cold bath to a hot bath without input power by utilizing heat from an additional "work" reservoir. Particularly interesting is a three-level design for a quantum absorption refrigerator, which can be optimized to reach the maximal (Carnot) cooling efficiency. Previous studies of three-level chillers focused on the behavior of the averaged cooling current. Here, we go beyond that and study the full counting statistics of heat exchange in a three-level chiller model. We explain how to obtain the complete cumulant generating function of the refrigerator in a steady state, then derive a partial cumulant generating function, which yields closed-form expressions for both the averaged cooling current and its noise. Our analytical results and simulations are beneficial for the design of nanoscale engines and cooling systems far from equilibrium, with their performance optimized according to different criteria, efficiency, power, fluctuations, and dissipation.

Radon in Estonian buildings. Establishment of a measurement system and obtained results

International Nuclear Information System (INIS)

Pahapill, L.; Rulkov, A.; Swedjemark, G.A.

1996-12-01

One purpose of this project was the establishment of a radon monitoring programme inside the state environmental monitoring programme. Another purpose was to investigate regions, expected to have high radon levels indoors. A new method for the long-term measurement of indoor radon was established and the staff for these measurements was trained. The results of the measurement can be used by Estonian decision-makers to work out rules and standards. There is no legislative act in the field of radiation in Estonian at this time. To summarize the results of the measurements we can say that indoor radon concentrations vary by region. The radon investigations must be continued to identify the risk areas and types of housing construction. The results of the state radon monitoring are provided to the municipalities, who advice the owners of planned new houses to select the right construction for the house. A new project will follow with an investigation of radon in randomly selected dwellings, training and equipment for radon measurement in soil, and general advice with regard to radon, as well as assistance in preparing information about radon. 7 refs, 5 figs

Current methodologies for assessing seismically induced settlements in soil

International Nuclear Information System (INIS)

Ledbetter, R.

1983-08-01

Earthquake-induced surface settlements have ranged from 0.7 to 10 percent of layer thickness for the relatively few incidences where reliable estimates have been made of settlement magnitudes and soil conditions. Standard penetration test results obtained for pre-earthquake and postearthquake conditions in Japan show that relative densities have changed from 188 percent increase to 44 percent decrease. At present, there are no verified methods of seismic settlement analysis. However, there are current methods of analysis ranging from empirical to fully theoretical, which take into account a few to all of the major variables affecting seismically induced settlement behavior. This report reviews pertinent current knowledge and methodologies related to this subject. 69 references, 9 figures

Is current clinical practice modified about intraoperative breast irradiation?

Science.gov (United States)

Massa, Michela; Franchelli, Simonetta; Panizza, Renzo; Massa, Tiberio

2016-04-01

After the results obtained in the two randomized clinical trial, the ELIOT trial and the TARGIT-A trial, a heated debate is going on concerning the question of applying intraoperative radiotherapy (IORT) instead of postoperative whole breast irradiation (WBI) after breast conservative treatment. Currently, many centers are applying the IORT following the strict selection criteria dictated by the working groups American Society for Radiation Oncology (ASTRO) and Groupe Européen de Curiethérapie-European Society for Therapeutic Radiology and Oncology (GEC-ESTRO) and monitoring the oncological outcome together with radiation toxicity on breast tissue. The clinical experience of the Geneva University Hospital regarding the use of the Intrabeam system is evaluated and compared with current evidences.

Recent results from neutrino interactions in heavy neon

International Nuclear Information System (INIS)

Baltay, C.; Caroumbalis, D.; French, H.

1978-01-01

We report recent results from an analysis of 100,000 pictures from the Fermilab 15 ft. bubble chamber filled with heavy neon and exposed to the double horn focused, wideband ν/sub μ/ beam. We have found 164 dilepton (μ - e + ) events with 33 vees, in good agreement with the GIM model of charm production. We have also observed the production of the charmed D 0 meson, followed by the decay D 0 → K 0 π + π - , at a rate of (0.7 +- 0.2)% of all charged current events. We have carried out searches for charm changing neutral current processes and for heavy lepton production, both with negative results; the upper limits obtained in these searches are given

EddyOne automated analysis of PWR/WWER steam generator tubes eddy current data

International Nuclear Information System (INIS)

Nadinic, B.; Vanjak, Z.

2004-01-01

INETEC Institute for Nuclear Technology developed software package called Eddy One which has option of automated analysis of bobbin coil eddy current data. During its development and on site use, many valuable lessons were learned which are described in this article. In accordance with previous, the following topics are covered: General requirements for automated analysis of bobbin coil eddy current data; Main approaches to automated analysis; Multi rule algorithms for data screening; Landmark detection algorithms as prerequisite for automated analysis (threshold algorithms and algorithms based on neural network principles); Field experience with Eddy One software; Development directions (use of artificial intelligence with self learning abilities for indication detection and sizing); Automated analysis software qualification; Conclusions. Special emphasis is given on results obtained on different types of steam generators, condensers and heat exchangers. Such results are then compared with results obtained by other automated software vendors giving clear advantage to INETEC approach. It has to be pointed out that INETEC field experience was collected also on WWER steam generators what is for now unique experience.(author)

Overview and initial results of the ETE spherical tokamak

International Nuclear Information System (INIS)

Berni, L.A.; Del Bosco, E.; Ferreira, J.G.; Ludwig, G.O.; Oliveira, R.M.; Shibata, C.S.; Barbosa, L.F.F.P.W.; Vilela, W.A.

2003-01-01

The ETE spherical tokamak is a small size aspect-ratio machine with major and minor radius of 30 cm and 20 cm, respectively. The vessel was made of Inconel 625 and provides good access for plasma diagnostics through 58 Conflat ports. The first plasma was obtained at the end of 2000 and presently plasma currents of about 45 kA lasting for about 4 ms with electron temperature up to 160 eV and densities of 2.2x10 19 m -3 are routinely obtained. Achievement of the designed parameters for the first phase of operation is expected by the end of this year, with plasma current up to 200 kA lasting for about 15 ms. This paper describes some details of the ETE project, construction and mainly the first results and analysis of basic parameters. (author)

Hydrodynamic behaviour of a gas—solid counter-current packed column at trickle flow

NARCIS (Netherlands)

Roes, A.W.M.; van Swaaij, Willibrordus Petrus Maria

1979-01-01

Trickle flow of a more or less fluidized catalyst through a packed column is a promising new gas—solid counter-current operation. The hydrodynamic, behaviour of such a column, filled with dumped PALL rings, has been investigated, while some results have been obtained with RASCHIG rings and

Analytic description of tokamak equilibrium sustained by high fraction bootstrap current

International Nuclear Information System (INIS)

Shi Bingren

2002-01-01

Recently, to save the current drive power and to obtain more favorable confinement merit for tokamak reactor, large faction bootstrap current sustained equilibrium has attracted great interests both theoretically and experimentally. An powerful expanding technique and the tokamak ordering are used to expand the Grad-Shafranov equation to obtain a series of ordinary differential equations which allow for different sets of input parameters. The fully bootstrap current sustained tokamak equilibria are then solved analytically

Comparison of visual field test results obtained through Humphrey matrix frequency doubling technology perimetry versus standard automated perimetry in healthy children.

Science.gov (United States)

Kocabeyoglu, Sibel; Uzun, Salih; Mocan, Mehmet Cem; Bozkurt, Banu; Irkec, Murat; Orhan, Mehmet

2013-10-01

The aim of this study was to compare the visual field test results in healthy children obtained via the Humphrey matrix 24-2 threshold program and standard automated perimetry (SAP) using the Swedish interactive threshold algorithm (SITA)-Standard 24-2 test. This prospective study included 55 healthy children without ocular or systemic disorders who underwent both SAP and frequency doubling technology (FDT) perimetry visual field testing. Visual field test reliability indices, test duration, global indices (mean deviation [MD], and pattern standard deviation [PSD]) were compared between the 2 tests using the Wilcoxon signed-rank test and paired t-test. The performance of the Humphrey field analyzer (HFA) 24-2 SITA-standard and frequency-doubling technology Matrix 24-2 tests between genders were compared with Mann-Whitney U-test. Fifty-five healthy children with a mean age of 12.2 ± 1.9 years (range from 8 years to 16 years) were included in this prospective study. The test durations of SAP and FDT were similar (5.2 ± 0.5 and 5.1 ± 0.2 min, respectively, P = 0.651). MD and the PSD values obtained via FDT Matrix were significantly higher than those obtained via SAP (P tests in terms of MD (r = 0.352, P = 0.008) and PSD (r = 0.329, P = 0.014) was observed. Children were able to complete both the visual test algorithms successfully within 6 min. However, SAP testing appears to be associated with less depression of the visual field indices of healthy children. FDT Matrix and SAP should not be used interchangeably in the follow-up of children.

Current practises and future needs - Results from ARGONA Work Package 1

International Nuclear Information System (INIS)

Lidberg, Maria; Andersson, Kjell

2009-12-01

The point of departure for the European Union ARGONA project is that participation and transparency are key elements of effective radioactive waste management. The project investigates how approaches of transparency and deliberation relate to each other and also how they relate to the political system in which decisions, for example on the final disposal of nuclear waste, are ultimately taken. As a basis for the analysis of this issue, one part of the project deals with the policy making structures that exist, such as Strategic Environmental Assessment and Environmental Impact Assessment Directives, as well as national nuclear safety and environmental legislation. The aim is to determine the framework within which new arenas for participation and transparency can be formed. A questionnaire was issued and sent to key organizations at national and local levels. The intention was to highlight issues that set the scene for e.g. site selection and involvement of stakeholders. One issue is the requirements for, but also if there are any limitations of, the use of novel public participation approaches (as compared to traditional participation such as receiving information, asking questions at public meetings and submitting written comments) within the legal systems. This paper describes the questionnaire and summarises the results of responses. Driving forces for transparency and participation are discussed, as well as current practices and future needs, and conclusions are made of relevance for the future development and application of new approaches

Current practises and future needs - Results from ARGONA Work Package 1

Energy Technology Data Exchange (ETDEWEB)

Lidberg, Maria; Andersson, Kjell (Karita Research AB, Taeby (Sweden)), E-Mail: kjell.andersson@karita.se

2009-12-15

The point of departure for the European Union ARGONA project is that participation and transparency are key elements of effective radioactive waste management. The project investigates how approaches of transparency and deliberation relate to each other and also how they relate to the political system in which decisions, for example on the final disposal of nuclear waste, are ultimately taken. As a basis for the analysis of this issue, one part of the project deals with the policy making structures that exist, such as Strategic Environmental Assessment and Environmental Impact Assessment Directives, as well as national nuclear safety and environmental legislation. The aim is to determine the framework within which new arenas for participation and transparency can be formed. A questionnaire was issued and sent to key organizations at national and local levels. The intention was to highlight issues that set the scene for e.g. site selection and involvement of stakeholders. One issue is the requirements for, but also if there are any limitations of, the use of novel public participation approaches (as compared to traditional participation such as receiving information, asking questions at public meetings and submitting written comments) within the legal systems. This paper describes the questionnaire and summarises the results of responses. Driving forces for transparency and participation are discussed, as well as current practices and future needs, and conclusions are made of relevance for the future development and application of new approaches

Statistical Analysis Of Tank 19F Floor Sample Results

International Nuclear Information System (INIS)

Harris, S.

2010-01-01

Representative sampling has been completed for characterization of the residual material on the floor of Tank 19F as per the statistical sampling plan developed by Harris and Shine. Samples from eight locations have been obtained from the tank floor and two of the samples were archived as a contingency. Six samples, referred to in this report as the current scrape samples, have been submitted to and analyzed by SRNL. This report contains the statistical analysis of the floor sample analytical results to determine if further data are needed to reduce uncertainty. Included are comparisons with the prior Mantis samples results to determine if they can be pooled with the current scrape samples to estimate the upper 95% confidence limits (UCL95%) for concentration. Statistical analysis revealed that the Mantis and current scrape sample results are not compatible. Therefore, the Mantis sample results were not used to support the quantification of analytes in the residual material. Significant spatial variability among the current scrape sample results was not found. Constituent concentrations were similar between the North and South hemispheres as well as between the inner and outer regions of the tank floor. The current scrape sample results from all six samples fall within their 3-sigma limits. In view of the results from numerous statistical tests, the data were pooled from all six current scrape samples. As such, an adequate sample size was provided for quantification of the residual material on the floor of Tank 19F. The uncertainty is quantified in this report by an UCL95% on each analyte concentration. The uncertainty in analyte concentration was calculated as a function of the number of samples, the average, and the standard deviation of the analytical results. The UCL95% was based entirely on the six current scrape sample results (each averaged across three analytical determinations).

[Current program of in-vitro fertilization at the Erasmus Hospital: initial results and original ethical aspects].

Science.gov (United States)

Englert, Y; Van den Bergh, M; Rodesch, C; Van der Vorst, P; Berberoglugil, P; Laruelle, C; Biramane, J; Gervy, C; Schwers, J

1991-10-01

The clinical results including all in vitro fertilization (IVF) cycles with oocyte pick-up in 1990 are presented. Different types of treatment including classical IVF and embryo transfer, laparoscopic replacement of zygotes in the fallopian tube (ZIFT), IVF with donor sperm (IVF-D), cross fertilization test, embryo freezing, oocyte donation and IVF with epididymal sperm were performed. The total pregnancy rate obtained reaches 38% per oocyte pick-up, 30% of clinical pregnancies (including 4 pregnancies obtained with frozen and thawed embryos). The anticipated "Take Home Baby Rate" will be around 25% per oocyte pick-up, 26 of these 40 pregnancies being today over 20 weeks of gestation. Particular ethical aspects of the program are presented: a study on couple's attitudes regarding embryo freezing as well as the final destination of possibly remaining supernumerary embryos will stress the importance of a precise clear decision on that matter before entering IVF treatment. Indeed the couple's idea on embryo destiny were very precise but also very different. The oocyte donation program has the originality of preserving the donor's anonymity by exchanging the donors recruited by the patients. It will be stressed that this kind of approach combines higher pregnancy chances for the patients, respect of ethical principles linked to gamete donation and gives satisfaction to the patients. The global normalized pregnancy cumulative curve shows that 60% of the couples entering IVF treatment will obtain a child within the first three pick-up cycles.

Quantum dot as a spin-current diode: A master-equation approach

DEFF Research Database (Denmark)

Souza, F.M.; Egues, J.C.; Jauho, Antti-Pekka

2007-01-01

We report a study of spin-dependent transport in a system composed of a quantum dot coupled to a normal metal lead and a ferromagnetic lead NM-QD-FM. We use the master equation approach to calculate the spin-resolved currents in the presence of an external bias and an intradot Coulomb interaction....... We find that for a range of positive external biases current flow from the normal metal to the ferromagnet the current polarization =I↑−I↓ / I↑+I↓ is suppressed to zero, while for the corresponding negative biases current flow from the ferromagnet to the normal metal attains a relative maximum value....... The system thus operates as a rectifier for spin-current polarization. This effect follows from an interplay between Coulomb interaction and nonequilibrium spin accumulation in the dot. In the parameter range considered, we also show that the above results can be obtained via nonequilibrium Green functions...

Welding Current Distribution in the Work-piece and Pool in Arc Welding

Directory of Open Access Journals (Sweden)

A. M. Rybachuk

2015-01-01

Full Text Available In order to select the optimal configuration of controlling magnetic fields and build rational construction of magnetic systems, we need to know the distribution of welding current in the molten metal of the weld pool. So the objective of the work is to establish the calculated methods for determining current density in the weld pool during arc welding. The distribution of welding current in the pool depends on the field of the electrical resistance, which is determined by the deformed temperature field while arc moves with the welding speed. The previous works have shown experimentally and by simulation on the conductive paper that deformation of temperature field defines deformation of electric field. On the basis thereof, under certain boundary conditions the problem has been solved to give a general solution of differential equation, which relates the potential distribution to the temperature in the product during arc welding. This solution is obtained under the following boundary conditions: 1 metal is homogeneous; 2 input and output surfaces of heat flux and electric current coincide; 3 input and output surfaces of heat flux and electric current are insulated and equipotential; 4 other (lateral surfaces are adiabatic boundaries. Therefore, this paper pays basic attention to obtaining the analytical solution of a general differential equation, which relates distribution of potential to the temperature in the product. It considers the temperature field of the heat source, which moves at a welding speed with normal-circular distribution of the heat flow at a certain concentration factor. The distribution of current density is calculated on the assumption that the welding current is introduced through the same surface as the heat flux and the distribution of current density corresponds to the normally circular at a certain concentration factor. As a result, we get an expression that allows us to calculate the current density from the known

Fault Current Characteristics of the DFIG under Asymmetrical Fault Conditions

Directory of Open Access Journals (Sweden)

Fan Xiao

2015-09-01

Full Text Available During non-severe fault conditions, crowbar protection is not activated and the rotor windings of a doubly-fed induction generator (DFIG are excited by the AC/DC/AC converter. Meanwhile, under asymmetrical fault conditions, the electrical variables oscillate at twice the grid frequency in synchronous dq frame. In the engineering practice, notch filters are usually used to extract the positive and negative sequence components. In these cases, the dynamic response of a rotor-side converter (RSC and the notch filters have a large influence on the fault current characteristics of the DFIG. In this paper, the influence of the notch filters on the proportional integral (PI parameters is discussed and the simplified calculation models of the rotor current are established. Then, the dynamic performance of the stator flux linkage under asymmetrical fault conditions is also analyzed. Based on this, the fault characteristics of the stator current under asymmetrical fault conditions are studied and the corresponding analytical expressions of the stator fault current are obtained. Finally, digital simulation results validate the analytical results. The research results are helpful to meet the requirements of a practical short-circuit calculation and the construction of a relaying protection system for the power grid with penetration of DFIGs.

Motivations toward smoking cessation, reasons for relapse, and modes of quitting: results from a qualitative study among former and current smokers

Directory of Open Access Journals (Sweden)

Buczkowski K

2014-10-01

Full Text Available Krzysztof Buczkowski,1 Ludmila Marcinowicz,2 Slawomir Czachowski,1 Elwira Piszczek3 1Department of Family Medicine, Collegium Medicum, Nicolaus Copernicus University, Torun, 2Department of Family Medicine and Community Nursing, Medical University of Bialystok, Bialystok, 3Sociology Institute, Nicolaus Copernicus University, Torun, Poland Background: Smoking cessation plays a crucial role in reducing preventable morbidity and mortality and is a recognized public-health-policy issue in many countries. Two of the most important factors that affect the efficacy of quitting smoking are motivation and the ability to cope with situations causing relapse.Aim: The objective of the study reported here was to investigate former and current smokers’ motivations for smoking cessation, reasons for relapse, and modes of quitting.Methods: We arranged four focus groups with 24 participants (twelve current and twelve former smokers and eleven semi-structured interviews (five current and six former smokers with a view to understanding and categorizing their opinions on motivations and the course and process of smoking cessation. The data were next analyzed using descriptive qualitative methods.Results: Three main themes were identified: (1 motivations to quit smoking, (2 reasons why smokers sometimes relapse, and (3 modes of quitting smoking. Within the first theme, the following six subthemes surfaced: (1 a smoking ban at home and at work due to other people’s wishes and rules, (2 the high cost of cigarettes, (3 the unpleasant smell, (4 health concern, (5 pregnancy and breastfeeding, and (6 a variety of other factors. The second theme encompassed the following subthemes: (1 stress and the need to lessen it by smoking a cigarette, (2 the need to experience the pleasure connected with smoking, and (3 the smoking environment both at home and at work. Participants presented different smoking-cessation modes, but mainly they were unplanned attempts.Conclusion: Two

Mass transfer in counter current flows

Energy Technology Data Exchange (ETDEWEB)

Doichinova, Maria D.; Popova, Petya G.; Boyadjiev, Christo B. [Bulgarian Academy of Science, Institute of Chemical Engineering, Sofia (Bulgaria)

2011-07-01

A theoretical analysis of gas-liquid counter-current flow in laminar boundary layers with flat phase boundary based on similarity variables method has been done. The obtained numerical results for the energy dissipation, mass transfer rate and their ratio are compared with analogous results for concurrent flows. A diffusion type of model is proposed for modeling of the mass transfer with chemical reaction in the column apparatuses in the cases of circulation zones. The presence of rising and descending flows (the change of the velocity direction) leads to using three coordinate systems. An iterative algorithm for the concentration distribution calculation is proposed. The influence of the zones breadths on the mass transfer efficiency in the column is investigated. Key words: efficiency, mass transfer, velocity distribution, column apparatuses, circulation zones.

Obtaining and Using Images in the Clinical Setting

International Nuclear Information System (INIS)

Cendales, Ricardo

2009-01-01

Currently small electronic devices capable of producing high quality images are available. The massive use of these devices has become common in the clinical setting as medical images represent a useful tool to document relevant clinical conditions for patient diagnosis, treatment and follow-up. Besides, clinical images are beneficial for legal, scientific and academic purposes. The extended practice without proper ethical guidelines might represent a significant risk for the protection of patient rights and clinical practice. This document discusses risks and duties when obtaining medical images, and presents some arguments on institutional and professional responsibilities around the definition of policies regarding the protection of privacy and dignity of the patient.

The dynamic current-voltage characteristic as a powerful tool to analyze fast phenomena in plasma

International Nuclear Information System (INIS)

Ivan, L. M.; Mihai-Plugaru, M.; Amarandei, G.; Aflori, M.; Dimitriu, D. G.

2006-01-01

The static current-voltage characteristic of an electrode immersed in plasma is obtained by slowly increasing and subsequently decreasing the potential on the electrode with respect to the plasma potential or the ground. This characteristic can give us important information about the phenomena that take place in front of the electrode. Current jumps can be evidenced which were often associated with an hysteresis effect, regions with S-type or N-type negative differential resistance, etc. The method is always used when we investigate the appearance of complex space charge configurations (CSCC) in front of an electrode immersed in plasma. However, to investigate the dynamics of such structures or other fast phenomena (like instabilities) which take place in plasma devices with frequencies of tenth, hundred kHz or more, complex investigation techniques must be used. One of the most efficient methods to investigate fast phenomena in plasma devices is the dynamic current-voltage characteristic. This is obtained by recording the time series of the current collected by the electrode when the voltage applied on it is very fast modified (most likely increased) by using a signal generator. In this way, very fast oscillations of the current can be recorded and new phenomena can be evidenced. We used this technique to study the phenomena which take place at the onset of electrostatic instabilities in Q-machine plasma, namely the potential relaxation instability (PRI) and the electrostatic ion-cyclotron instability (EICI). The obtained experimental results prove that the negative differential resistance region in the static current-voltage characteristic is the result of a nonlinear dynamics of a CSCC in form of a double layer (DL) which takes place just before the onset of the instabilities. In the case of the PRI we emphasized current jumps related with the DL appearance, which are not present in the static current-voltage characteristic at high plasma density. (authors)