... AC Loss Minimisation in High Temperature Superconductors ... Extension to AC Loss Minimisation in High Temperature Superconductors ...
DTIC Science & Technology
This report discusses the AC losses in the MICE channel magnets during magnet charging and discharging. This report talks about the three types of AC losses in the MICE magnets; the hysteretic AC loss in the superconductor, the coupling AC ...
National Technical Information Service (NTIS)
... YBCO Coated Conductors with Reduced AC Losses ... YBCO Coated Conductor, AC losses, RABiTS, Superconductor, Maganetic Properties ...
... Extension to AC Loss Minimisation in High Temperature Superconductors ... The transport AC loss decreases more than 3 times. ...
AFRL-PR-WP-TP-2006-208 AC LOSS REDUCTION OF YBCO ... SUBJECT TERMS AC losses, coated conductors, YBCO, multifilamentary 16. ...
... Abstract : Results are presented on the AC and DC characteristics of Wausau granite which show that excess AC losses at low temperatures are ...
... Accession Number : ADA461815. Title : AC Loss Reduction of YBCO Coated Conductors by Multifilamentary Structure. Descriptive ...
... Title : AC LOSSES OF SUPERCONDUCTING COMPOSITES WITH 8 MU-M NBTI FILAMENTS IN A DC MAGNETIC FIELD WITH A ...
A simple model gave utilized for calculation of magnetization effects on ac loss and sextupole for Energy Doubler dipole magnets. The calculation in the simple model gave an underestimation of ac loss by about 30%. Results of computation on ac harmonics were also described.
DOE Information Bridge
This report discusses the AC losses in the MICE channelmagnets during magnet charging and discharging. This report talks aboutthe three types of AC losses in the MICE magnets; the hysteretic AC lossin the superconductor, the coupling AC loss in the ...
Energy Citations Database
Ac loss measurements have been performed in samples of a prototype conductor being developed for application in the central solenoid of NET. Two types of losses have been measured: hysteresis losses in the strand, and coupling losses in the strand, subcab...
The theory and calculation of a.c. losses in type II superconducting materials and superconducting coils are presented. The calculated losses are compared to loss-measurements in solenoids performed by several laboratories. Methods of loss measurements are described. (author)
Page 1. AFRL-PR-WP-TP-2006-210 LOW AC LOSS STRUCTURES IN ... 2, JUNE 2005 2827 Low AC Loss Structures in YBCO Coated Conductors ...
This paper discusses the physics of ac losses in type-II superconductors and in multifilamentary superconducting-normal composite conductors. As an introduction, the ac eddy-current losses in a homogeneous normal conducting cylindrical specimen subjected ...
This lecture discusses the physics of ac losses in type-II superconductors and in multifilamentary superconducting-normal composite conductors. As an introduction, the ac eddy-current losses in a homogeneous normal conducting cylindrical specimen subjecte...
... Accession Number : ADA481255. Title : YBCO Coated Conductors with Reduced AC Losses. Descriptive Note : Final technical rept. ...
... Accession Number : ADA346511. Title : Program to Study AC Loss in High-Tc Superconductors. Descriptive Note : Final technical rept. ...
... Accession Number : ADA038393. Title : Measurements of AC Losses in Superconductors below Hc1. Descriptive Note : Final rept. Jan 74-Jun 76,. ...
... Title : Low AC Loss Structures in YBCO Coated Conductors With Filamentary ... Personal Author(s) : Barnes, Paul N. ; Levin, George A. ; Varanasi ...
... Abstract : This report results from a contract tasking University of Cambridge as follows: The contractor will investigate: 1) AC losses of appropriate ...
... report results from a contract tasking University of Cambridge as follows: The contractor will investigate: (a) Measure the AC losses of appropriate ...
... Title : Critical Currents and AC Losses in Model YBCO ... HALL EFFECT, ELECTRIC FIELDS, ALTERNATING CURRENT, OXIDES, COPPER ...
... Using the two-dimensional FEM model for electromagnetic field analysis of coated conductors, the AC losses at various conditions were calculated ...
... Title : AC LOSSES IN A MULTIFILAMENTARY NB3AL/CU COMPOSITE SUPERCONDUCTOR MADE BY A JELLY ROLL PROCESS. ...
... TERMS magnetization losses, superconductor, YBCO coated ... of coated super- conductors in demanding ac ... Theory of Superconductors Tay- lor and ...
... ALTERNATING CURRENT, CRITICAL TEMPERATURE, LOSSES, HYSTERESIS, UNITED KINGDOM, YTTRIUM BARIUM COPPER OXIDES. ...
... SUPERCONDUCTORS, *ELECTRIC FIELDS, *ALTERNATING CURRENT ... SURFACE PROPERTIES, THINNESS, SCALAR FUNCTIONS, LOSSES ...
... The main obstacle to the use of superconductors in electrical machines in ... superconducting cylinder (ie the losses in the superconductor plus the ...
... MATHEMATICAL MODELS, ALTERNATING CURRENT, LOSSES, MAGNETIZATION, COPPER OXIDES, YTTRIUM OXIDES, BARIUM OXIDES ...
The objective of the program was to study the feasibility of Nb3Ge being used as an AC superconducting power transmission cable material. Specifically, the program was to measure AC losses in available samples of Nb3Ge and find under what conditions the l...
... are superconducting. The design of such a machine is dominated by the AC losses which occur in the armature. Most superconducting ...
AC losses must be considered in SMES during discharging of the coil. This is especially true for very fast discharges. In particular, the SMES/Engineering Test Model (ETM) should be able to demonstrate the capability to discharge at 400 MW for 100 seconds. It is important to quantify AC losses to ascertain its ...
The feasibility of superconductors for alternating current use depends on successful reduction of losses. Moreover, the demand for large field amplitudes is a stimulation for investigating the nature of a.c. losses (e.g. in the set of poloidal coils in a ...
An empirical relation is presented which allows simple computation of volume-averaged winding fields from central fields for coils of small rectangular cross sections. This relation suggests that, in certain applications, ac-loss minimization can be accomplished by use of low winding densities, provided that hysteresis losses are independent of winding ...
Reduction of ac losses in applied ac fields can be accomplished through either the creation of filaments and bridging in YBCO coated conductors or an assembly of narrow width YBCO tapes. The ac losses for each of these geometries were measured at 77 K in perpendicular ac ...
AC loss is one of the main issues in the design of the CICC used for PF and TF coils of superconducting tokamak. A preliminary calculation of AC loss for the designed HT-7U CICCs used for TF magnets is given in this paper. We only consider the hysteresis and coupling losses related to ...
NASA Astrophysics Data System (ADS)
Magnetization AC losses in striated YBCO conductors in a perpendicular applied AC magnetic field were investigated with special regard to the coupling current AC loss (CCAC). The AC loss of YBCO samples of different length L was measured by using ...
... and References Search GIVE BACK � RELATED LINKS ACS Gift Shop ACS Bookstore MoreBirthdays.com ACSCAN.org Hair Loss ...
MedlinePLUS
... motion compensation will be assumed to avoid any target signal loss incurred in integration. ... the DC part &(v) and the AC spectrum pAc(v) due to ...
Development of the superconducting transformer is arguably the most difficult of the ac power applications of superconductivity - this is because of the need for very low ac losses, adequate fault and surge performance, and the rigors of the application e...
AC losses increased rapidly with frequency and quadratically with AC amplitude. Above about 2 hz, the effective resistance of the control coils exceeds that ...
NASA Website
Critical currents and AC losses of (Bi, Pb)2Sr2Ca2Cu3Ox superconducting tapes were measured in self-field as a function of temperature. The experimental data of the temperature dependence of critical current were compared with calculated results. An approach to calculating AC losses as a function of temperature was ...
In this paper a description is given of a method to measure calorimetrically ac losses in superconducting samples. The boil-off gas is stored below the liquid helium level in a measuring tube. Losses in the range of 1 mW up to 100 mW can be measured with an accuracy of 3%. Results of measurements of ac ...
In order to apply widely the superconductivity technology to electric power equipments, the development and evaluation on the AC superconducting cables have been conducted in the Central Research Institute of Electric Power Industry. The superconducting c...
This lecture discusses the physics of ac losses in type-II superconductors and in multifilamentary superconducting-normal composite conductors. As an introduction, the ac eddy-current losses in a homogeneous normal conducting cylindrical specimen subjected to an alternating applied magnetic field are briefly ...
ac losses of superconducting solenoidal coils were investigated with a calorimetric method while applying a current or uniform magnetic field of 50 Hz with a sinusoidal wave form. The peak value of the ac current was varied from 0 to 15 rms A and that of the ac magnetic field from 0 to 0.02 T. These experimental ...
AC losses in a superconductor strip are numerically evaluated by means of a finite element method formulated with a current vector potential. The expressions of AC losses in an infinite slab that corresponds to a simple model of infinitely stacked strips are also derived theoretically. It is assumed that the ...
A report is given of calorimetric measurements of the ac losses of a small superconducting coil wound from a filament superconductor designed for low ac losses (filament phi = 8 $mu$, number of filaments 1045, CuNi barriers). The coil was pulsed with a maximum dB/dt = 480 kG/s. Further the ...
This study investigated the combined function of the Autographa californica multiple nucleopolyhedrovirus overlapping genes ac16 (BV/ODV-E26, DA26) and ac17. Ac17 is a late gene and the promoter is within the ac16 open reading frame. A double ac16-ac17 knockout virus was ...
PubMed
The final goal of the program is to establish standard measurement practices and a standard reference material for calibration of apparatus. In this paper the authors discuss a comparison of several techniques for measuring ac losses in superconductors. The techniques are divided into either a calorimetric or electronic type.
It is demonstrated for the first time that a relatively large cryostable superconducting coil can be pulsed with relatively low ac losses at high ramping rates. The low ac losses with limited current sharing have been achieved by insulating the surface of...
The objective of the study is to estimate the probability of failure of the battery system of a nuclear power plant due to loss of ventilation in the battery room during AC blackout. This is part of the more general problem of the interaction between non-...
Nov 24, 2008 ... In a NASA SBIR Phase I and Phase II program we want to develop low AC loss MgB2 superconductors for the stators of synchronous motors or ...
An improved electronic method for measuring ac losses in superconducting cables of lengths from 1m to 10m has been developed and is described. This method compensates for phase shifts in the measuring circuit elements and for imbalance of the difference a...
Energy dissipation, which is also called AC loss, of a composite multifilamentary superconducting wire is one of the most fundamental concerns in building a stable superconducting magnet. Characterization and reduction of AC losses are especially importan...
The measurement of ac losses in superconducting cables by calorimetric means is necessary as a verification of electronic measurements on short high-current models and because the present method of electronic measurement is not applicable to longer cables...
A calorimeter has been developed to measure the total core loss in small samples of magnetic materials which are not suited to conventional measurement techniques. The method is similar to the helium boil-off calorimeter used in some cases to measure ac l...
AC losses in full length and 1.5 m model SSC collider dipoles were successfully measured by the direct observation of energy flow into and out of magnets during a ramp cycle. The measurement was performed by using two double-integrating type digital volt ...
Since 1995 Southwire Company and Oak Ridge National Laboratory (ORNL) have jointly designed, built, and tested nine, l-m long, high temperature superconducting (HTS) transmission cable prototypes. This paper summarizes the AC loss measurements of five of ...
A new cryostat cooled by a closed-cycle Cryomech GB-37 cryocooler for superconductor measurements at temperatures down to 20 K is described. The sample is conductively coupled to the cold stage so as to minimize vibration and thermal stresses. AC losses h...
From the time constant and the hysteresis loss measurements of the subcables, it is estimated that approximately 60% of the ac losses of the ANL 3.3 MJ coil at 6 T/s of the central field are due to the losses within the 19-strand subcable itself. The remaining 40% of the losses seem to come ...
... Work has been performed on the theory of ac losses in multifilament superconductors and experiments were made to check the theory. ...
... Abstract : The theory of magnetohydrodynamic power generators is presented. ... sectional area flows; end losses; AC generation; cycle efficiencies ...
An empirical relation is presented which allows simple computation of volume-averaged winding fields
NASA Technical Reports Server (NTRS)
A superconducting tape having reduced AC losses. The tape has a high temperature superconductor layer that is segmented. Disruptive strips, formed in one of the tape substrate, a buffer layer, and the superconducting layer create parallel discontinuities in the superconducting layer that separate the current-carrying elements of the superconducting layer ...
DOEpatents
... Abstract : ;Contents: Uses of low temperatures; Materials; Ac losses in superconductors; Superconducting, Magnets; Energy storage and ...
... X-ray induced ac losses in TFE resins (previously reported) are greatly influenced by the presence of oxygen during sintering. ...
... AC losses and proximity effects in the composites need careful consideration in the evolution of a practical composite conductor. (Author). ...
... HIGH TEMPERATURE, *SINGLE CRYSTALS, *SUPERCONDUCTORS, *ELECTRIC CONDUCTORS, *YTTRIUM BARIUM COPPER OXIDES ...
... Abstract : This report deals with two properties of high field superconductors; namely, their critical current density and ac losses. ...
This paper describes measured AC losses of NbTi Rutherford type cable when the wide side of the cable is parallel to the field variation. In the case of a Rutherford type cable, the orientation of the cable in the magnetic field is an important factor for the interstrand coupling loss which can be dominant over other ...
The report deals with hysteresis losses at 4 K measured by magnetization and complex magnetic susceptibility. The theoretical and experimental relationships between ac susceptibility and magnetization as functions of dc field were examined in terms of the...
... Abstract : Theoretical and experimental studies of the ac losses in continuous fine filament superconductors and in situ Nb3Sn superconductors are ...
We are experimentally studying basic AC loss properties of IBAD/CVD-YBCO coated conductors with a copper layer for stabilizing, especially the temperature dependence of perpendicular field loss in alternating electromagnetic environments. We prepared two types of short specimens with and without a copper layer and measured ...
We present measurements of AC losses in Bi-2223 multi-pancakes coils with different geometries. Measurements were performed at 77 K at frequencies ranging from 50 to 1600 Hz. The losses are found to depend strongly on coil configuration and linearly increase with increasing frequency. The centre pancakes in the coils exhibit larger ...
We have manufactured a small circular superconducting coil impregnated with epoxy fibreglass. The coil was wound from a Bi-2223/Ag superconducting wire and it was tested in liquid nitrogen at 77 K. Current-voltage characteristic and the AC losses of the coil were measured and compared with the measurements on the original tape. The AC ...
Alternating current loss as a function of current and external magnetic field in commercial NbTi superconductors has been measured with an electronic wattmeter. The loss varies as the current cubed, and the increase of loss with the external magnetic fiel...
An AC bridge technique is described for measuring energy losses in multifilament (MF) superconductors due to alternating current flow in superconducting solenoids. Superconductivity and transient loss theory are briefly discussed, and the apparatus used to measure the losses is described in detail. ...
A description will be given of a new method to measure calorimetrically ac losses in superconducting samples. The boil-off gas is stored below the liquid helium level in a measuring tube. Losses in the range of 1 mW up to 100 mW can be measured with an ac...
Superconducting dipole magnets for accelerators have shown various quench current degradations and unexpected field disturbances even when they were fabricated with the same cables. Such degradations become harmful in terms of the stable operation of accelerators. The reasons for the degradations seem to be caused by AC losses due to coupling currents ...
We present here results of our study of the 5-m-long AC transmission tine model with 1 kA current capability at 77 K. Primary attention was paid to the current characteristics and AC losses in individual tapes and in the core of the cable. The losses were...
In this paper the AC losses requirement for the superconducting coils of the Next European Torus (NET) project are discussed on the basis of the pulsed field scenario and plasma disruptions. The AC losses test results on the prototype 40 kA cable-in-conduit superconductors developed for NET are presented: the ...
The frequency dependence of magnetic ac loss of thin superconductor strip subjected to an ac magnetic field perpendicular to the surface of the strip is investigated by incorporating a flux creep model into the critical state model of Brandt and Indenbom. It is found that the reduced ac loss ...
We present here results of our study of the 5-m-long AC transmission tine model with 1 kA current capability at 77 K. Primary attention was paid to the current characteristics and AC losses in individual tapes and in the core of the cable. The losses were measured as a function of AC magnetic ...
Theoretical and experimental studies of the ac losses in continuous fine filament superconductors and in situ Nb3Sn superconductors are reported. The results indicate that surface currents may play a major role in determining the loss and critical current characteristics of fine filament superconductors. In situ superconductors hold ...
Inter- and intra-granular ac losses in the superconducting state of ceramic high-temperature superconductors are calculated using a Kim-like critical state model for the inter-granular loss contribution and a Bean model for the intra-granular loss. Good agreement with experimental data over a wide magnetic field ...
The phase-space of convective and diffusive fast-ion losses induced by shear Alfv�n eigenmodes has been characterized in the ASDEX Upgrade tokamak. Time-resolved energy and pitch-angle measurements of fast-ion losses correlated in frequency and phase with toroidal Alfv�n eigenmodes (TAEs) and Alfv�n cascades (ACs) have allowed to ...
A calorimeter has been developed to measure the total core loss in small samples of magnetic materials which are not suited to conventional measurement techniques. The method is similar to the helium boil-off calorimeter used in some cases to measure ac losses in superconductors. Power losses in the sample are ...
A calorimeter for measuring ac losses in meter-long lengths of HTS superconducting power transmission line cables is described. The calorimeter, which is based on a temperature difference technique, has a precision of 1 mW and measures single, two-phase (coupling), and three-phase losses. The measurements show significant coupling ...
From the time constant and the hysteresis loss measurements of the subcables, it is estimated that approximately 60% of the ac losses of the ANL 3.3 MJ coil at 6 T/s of the central field are due to the losses within the 19-strand subcable itself. The rema...
This paper describes the design of a new test system. It is under construction now and will be used to measure the AC losses of subcable from NET conductors. A special feature of the test arrangement is that the losses will be determined while the sample carries a transport current and is at the same time subjected to changing magnetic ...
We studied magnetic properties of biaxially textured Ni_1-xWx materials with x = 0, 3, 5, 6, and 9 at% W. They are important as substrates for ``RABiTS'' coated conductors containing high temperature superconductors. The quasi-static dc and ac hysteretic loss W was determined to estimate the ferromagnetic (FM) contribution to the overall ...
The complex AC susceptibility ((chi)) of high T(sub c) superconducting materials has been described in terms of hysteretic and AC losses. By including both flux creep and flux flow resistivities in the expression of the flux diffusivity, induction profile...
A dielectric loss study of porous MgO indicates that H2O absorption on MgO probably leads to the formation of surface defects as well as hydroxide ions. The ac conductivity, sigma sub ac followed the equation sigma sub ac=sigma sub 1 + KP sub H2O to the 0...
High temperature superconducting (HTS) cables with RE-123 coated conductors are expected to lower AC loss compared to that with BSCCO cable. Sumitomo Electric Industries, Ltd. (SEI) has been developing not only BSCCO wires but also RE-123 coated conductors. Recently, SEI has developed a RE-123 coated conductor with a new type of textured metal substrate ...
The setup for measuring ac-losses in short (up to 33 cm) samples of heavy-current superconducting cables is described. A calorimetric method is used for measuring losses. The sample placed into the calorimeter is in the external pulsed field. This field w...
Theoretical and experimental studies of the ac losses in continuous fine filament superconductors and in situ Nb3Sn superconductors are reported. The results indicate that surface currents may play a major role in determining the loss and critical current...
The ac losses in superconducting vanadiura are measured before and after the implantation with 75 keV Ga-ions. A pronounced increase of the surface shielding capacity resulting in a decrease of the energy losses is observed. (auth)
The magnetization loss density in stacked GdBa2Cu3O7?? coated conductor was measured using a SQUID magnetometer in a magnetic field normal to the tape surface to investigate the effect of stack on the magnetization loss. The AC loss characteristics are successfully collapsed to a single curve by the normalization ...
Power cables are one of the most promising applications for the superconducting coated conductors. In the AC use, only small resistive loss is generated, but the removal of the dissipated heat from the cryostat is inefficient due to the large temperature difference. The aim of this work is to minimize the AC losses ...
Recent results are reported pertaining to research of ac losses in superconductors with regard to magnet technology. Emphasis is on aspects which are important in demonstrating the technical feasibility and economical advantages of ac superconducting windings. In the domain of hysteresis losses the paper reports ...
Magnetic field fluctuations are inevitable in practical applications of superconductors and it is often necessary to estimate the AC losses these fluctuations induce. If the fluctuation wavelength is greater than the size of a superconductor, known estimates for an alternating uniform external magnetic field can be employed. Here we consider the opposite ...
E-print Network
This paper presents a new finite-element simulation model for computing the electromagnetic properties and AC losses in systems of YBCO (yttrium barium copper oxide) conductors on roll assisted biaxially textured substrates (RABiTS). In this model, the magnetic field dependent permeability and ferromagnetic loss of the substrates in ...
... The AC losses measured in pancake A at 3 frequencies, 54 Hz, 432 Hz and 864 Hz are shown in Figure 32. ... f = 432 Hz 900 mW 2.08 mJ 26 ...
Three areas related to the actively controlled radial magnetic bearing concepts are discussed. These areas are: (1) modification to the ac loss calculations of the 1990 report; (2) a continuous changing mechanism to compensate rotor current drop due to ac...
of track data for two aircraft (AC1 and AC2) leading up to the loss of ... error between reality and our model using statistics and formal methods. ... scenarios , small satellite design, and medical device design. ...
AC losses determined with a helium boil-off calorimeter qualitatively agree with those predicted from DC magnetization measurements for a number of niobium and niobium-zirconium superconducting samples. This is consistent with a hysteretic model of AC los...
The results are presented of investigations into the determination of the ac/dc resistance ratios of high and extra high voltage pipe-type cables with conventional and large size segmental conductors in carbon steel, stainless steel and aluminum pipes in ...
Results are given for the permeability, conductivity, and dielectric constant of a multifilament superconductor, treated as an anisotropic state of matter. The calculations are made for the limiting cases of strong and weak ac magnetic fields compared with the field required for complete penetration of the filaments. General expressions are given for the ...
Magnetization and ac susceptibility of a standard NbTi superconductor were measured as a function of longitudinal dc magnetic field. The ac-field-amplitude and frequency dependences of the complex susceptibility are examined. The magnetization is related to the susceptibility by means of a theoretical derivation based on the field dependence of the ...
Energy dissipation, which is also called AC loss, of a composite multifilamentary superconducting wire is one of the most fundamental concerns in building a stable superconducting magnet. Characterization and reduction of AC losses are especially important in designing a superconducting magnet for generating ...
The assembly of meander shaped coated conductor tapes by the Roebel technique is a promising way to manufacture high current cables with low ac losses. The application of longitudinal striations to the single strands can be an option to create a filament structure for further possible reduction of the ac losses. ...
Formulae are presented for the eddy current AC power loss and the AC hysteresis loss of z-stacks and x-arrays made of metal-superconductor strips. The AC self-field case and the applied AC magnetic field case are examined for different stacking spacings of a z-stack and ...
Since 1995 Southwire Company and Oak Ridge National Laboratory (ORNL) have jointly designed, built, and tested nine, l-m long, high temperature superconducting (HTS) transmission cable prototypes. This paper summarizes the AC loss measurements of five of the cables not reported elsewhere, and compares the losses with each other and ...
Calorimetrically determined energy losses for a series of niobium and niobium-25 at.% zirconium samples carrying an ac transport current agreed with those calculated from hysteresis loops determined by dc magnetization measurements. The results of this study showed that the energy losses in ultra-high-purity annealed Nb are less than ...
An analysis of a new method for measuring ac losses in superconducting magnets is described. The integral of compensated voltage across the magnet and a magnet current differential are multiplied. The result of multiplication is integrated and digitally displayed. The accuracy of the electronic joulemeter based on the double integration method is discussed ...
The measurement of ac losses in superconducting cables by calorimetric means is necessary as a verification of electronic measurements on short high-current models and because the present method of electronic measurement is not applicable to longer cables with simultaneously applied high current and voltage. Consequently, after the first tests of Cable No. ...
The thermo-hydraulic analysis of plant response on total loss of AC power is very demanding and challenging job due to a number of phenomena included. Such an analysis becomes even more complicated and interesting if we include also the assumption of tota...
Although much research has been conducted concerning the losses of high-(Tc) superconductors, very little has concentrated on the self-field losses in an actual magnet arrangement. The coils studied in this work were designed for use as actual magnets in ...
The properties of ac hysteresis loop of a stator tooth in a 5 hp induction motor was measured and analyzed. The load increase on the motor decreased magnetic induction, however increase the minor hysteresis loops in the high induction region. This effect caused increase in the core loss. Depending on condition of the motor, the core ...
Superconductors with inhomogeneous or filamentary structures are able to carry current distributed right across their cross sections. Because of flux- trapping properties, the form of current distribution will in general depend on the previous history of the specimen and, if a-c are carried, hysteresis in the current distribution is to be expected. This is equivalent ...
AIR CONDUCTED OCULAR VEMP: II. FIRST CLINICAL INVESTIGATIONSBACKGROUND: Vestibular-evoked myogenic potentials (VEMP) are widely used to assess vestibular function. Air conducted (AC) cervical VEMP (cVEMP) reflect sacculus and inferior vestibular nerve function. Ocular VEMP (oVEMP) however has been hardly examined up to now. In recent studies it has been assumed that ...
This paper discusses the physics of ac losses in type-II superconductors and in multifilamentary superconducting-normal composite conductors. As an introduction, the ac eddy-current losses in a homogeneous normal conducting cylindrical specimen subjected to an alternating applied magnetic field are briefly ...
For the design of a high temperature superconductor (HTS) power transformer the AC loss is a critical issue because the energy is dissipated as heat in the low temperature. It is necessary to study the AC losses theoretically and experimentally. For the analysis of AC ...
Self-field ac losses were measured by the conventional ac four-probe method in biaxially aligned Y{endash}Ba{endash}Cu{endash}O tapes using polycrystalline Hastelloy tapes with textured yttria-stabilized-zirconia buffer layers. The ac losses increased in proportion to the fourth power of ...
We have been developing a light weight and high efficiency superconducting traction transformer for railway rolling stock. We designed and fabricated a prototype superconducting traction transformer of a floor-mount type for Shinkansen rolling stock in 2004. We performed the type-test, the system-test, and the vibration-test. Consequently, we could verify that the transformer satisfied the ...
High temperature superconducting (HTS) cables using YBCO tapes are expected to be more economical because AC losses will be much smaller than conventional cables. To reduce AC loss, 10 mm wide YBCO tapes were divided into five strips using a YAG laser. Using narrower strips and optimizing the space between the ...
We investigate the AC loss of a high-0953-2048/10/8/004/img2 superconducting power-cable conductor with four layers and interlayer insulation. The electric-circuit model is applied for the calculation of the AC loss of the conductor. The result of a calculation for the AC ...
To achieve low ac losses in applied ac fields, YBa2Cu3Ox (YBCO) filaments were created on a RABiTS buffered substrate through solution inkjet deposition. The metal organic decomposition (MOD) solution was placed into an inkjet nozzle and filaments of widths of 100 ?m and 0.8 mm were placed on the substrate at a spacing of 50 to 100 ?m. ...
A new ac loss behaviour is observed in the superconducting state of Bi(2)Sr(2)CaCu(2)O(8) single crystals using a novel technique of measuring dissipation at radio frequencies. It is found that�the ac loss in the superconducting state is larger than that in the normal state. This counter-intuitive result is ...
The successful application of superconductivity to motors and other power system components depends on the characterization and subsequent minimization of the ac loss in the superconductor used for fabrication of the component. The superconductive component, excited by an ac power source, may be exposed to large dc magnetic fields ...
The authors report single-phase ac loss measurements on 8, 4, and 3-layer, multi-strand, HTS prototype conductors for power transmission lines. They use both calorimetric and electrical techniques. The agreement between the two techniques suggests that the interlayer current distribution in one-meter long conductors are representative of those in long ...
The ac losses of differently twisted samples of a multifilament superconductor in a magnetic field B=B/sub s/ +B/sub 0/ sin..omega..t have been measured. The over-all loss per cycle has a maximum at a frequency f/sub m/, which shifts to smaller frequency values with decreasing twist rate. At certain frequencies a multifilament ...
For high magnetic field operation at cryogenic temperatures near 20 K, the best lightweight conductor presently available is high-purity aluminum, sometimes referred to as a hyperconductor. However, because of its high purity, the material is mechanically weak, and because of its high conductivity the conductor must be fabricated as fine twisted strands to reduce ac eddy ...
It is demonstrated for the first time that a relatively large cryostable superconducting coil can be pulsed with relatively low ac losses at high ramping rates. The low ac losses with limited current sharing have been achieved by insulating the surface of the basic cable with thin organic film. The ...
Numerical simulations of hysteretic ac losses in a bilayer superconductor/ferromagnet heterostructure subject to an oscillating transverse magnetic field are performed within the quasistatic approach, calling upon the ANSYS finite-element software program and exploiting magnetostatic-electrostatic analogs. It is shown that one-sided magnetic shielding of a ...
A pair of coupling solenoids is used in MICE experiment to generate magnetic field which keeps the muons within the iris of thin RF cavity windows. The coupling solenoids have a 1.5-meter inner diameter and will produce 7.4 T peak magnetic field. Three types of AC losses in coupling solenoid are discussed. The affect of AC ...
A.c. losses caused by an a.c. transport current and a transverse a.c. magnetic field during simultaneous action were measured. The loss contributions have been obtained separately. The measurements were performed on a NbTi multifilamentary wire having a CuNi matrix of low conductivity in order ...
This study investigated the potential usage of activated carbon (AC) as a permeable reactive barrier material for the adsorption of benzene contaminant. Sodium persulfate (SPS) or pyrite (FeS(2)) activated SPS oxidation was used for the regeneration of spent AC. Results indicate that persulfate oxidation of AC caused a ...
A series of Bi-2223 ([Bi, Pb]:Sr:Ca:Cu:O = 2:2:2:3) tapes with 37 superconducting core filaments was investigated in an attempt to correlate critical current and alternating current (AC) losses with twist-pitch. The twist-pitch of these multi-filamentary tapes which were produced by the powder-in-(Ag)tube (PIT) method varies from 8, 10, 13, 30, 50, 70 mm ...
The magnetic properties, including ac core loss, dc hysteresis loss, eddy current loss, ac and dc permeability at 10 kG and 15 kG, and magnetic flux density at field strength 2,500 A/m, of 17 heats of fully processed, continuous-annealed low-carbon electrical steels with grain diameter from ...
The DC magnetization and AC complex magnetic susceptibilities were measured for MgB2 single crystals, unsubstituted and carbon substituted with the composition of Mg(B0.94C0.05)2. The measurements were performed in AC and DC magnetic fields oriented parallel to the c-axis of the crystals. From the DC magnetization loops and the AC ...
Harris@ozone-sec.ch.cam.ac.uk Alain Hauchecorne Quantification of the Transport ... Gerhard Kopp Evolution of Chlorine Activation and Ozone Loss over Kiruna ...
The effects of metallurgical processing on 60 Hz ac losses and dc critical currents in Nb/sub 3/Sn tapes fabricated by the solid state diffusion technique were investigated. An addition of Al to the Cu--Sn alloy for the matrix resulted in large reduction in the ac losses of Nb/sub 3/Sn tapes, but the highest linear ...
... Effect of Twins on Critical Currents of High Tc Superconductors" - AM Campbell ... from AC losses in the superconductor, magnets rotating about their ...
A compact, easy to fabricate, noninductive, low surface magnetic field superconductor transmission line that has minimal stay fields is described.
... outward flow of the electrons by diffusion (in the pressure range 0.1 to 10 rm Hg the loss of electrons and ions is due mainly to ambipolar diffusion). ...
The magnitude of AC losses from a superconducting coil strongly indicates that the predicted scaling
A power grid is a transmission network transporting electrical energy from power plants to some substations near urban or industrial centers. To reduce the loss ...
... electric effect. It was also shown that heat power losses due to the ac- tive element in radiating transducers are dependent upon past thermal, 15 ...
The failure of the Y-wheel without reconfiguration for three wheel operation would result in loss of sun pointing and earth avoidance control. ...
AC losses of NbTi-Cu and NbTi-Cu-CuNi superconducting composite magnets have been measured by means of an electronic integration technique. The experimental results are presented and their qualitative comparisons are made. It is shown within our experimental range that: (1) AC losses of NbTi-Cu composite magnet are ...
... low-tem- perature superconductors where crystal ... necessarily true for high-temperature super- conductors. ... temper- ature superconductor in regard ...
... the utility of patterning or striping the conductor (at least from a short-sample standpoint) using YBCO films deposited on single crystal substrates [9 ...
... S2 interferometric non-contact displacement measurements ... loss and low ac stiffness so that a ... 18 From these measurements, the large signal ...
Mar 1, 2011 ... AC signal testing included impedance, capacitance and dielectric loss factor of .... A multi-year program, MOST (Mars Optimized Solar Cell ...
Mar 1, 2011 ... 91. Low Ac Loss Superconducting Coils for a Wind Tunnel Magnetic ... Abstract: Thermal expansion of yttrium oxide and of magnesium oxide ...
