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In this paper, we present the usability evolution of human-computer interactions. In addition, we group the various user interfaces of human-computer interaction into two generations with three classes each. The most user interfaces for human-computer interaction are assigned into a class depending on objective criteria scores, such as technical literacy level, level of natural interactions, user learning curve and UI’s ability to adapt. In addition, current tendencies for HCI are presented and future perspectives are discussed. Finally, we summarize the achieved results and draw conclusions.

The study and application of the materials that are stable in the temperature range up to 1000°C are necessary to repair forming dies operating in this range. Nickel-based alloys can be used for this purpose. The structural state of a nickel alloy layer deposited onto a KhV4F tool steel and then heat treated is investigated. KhV4F tool steel (RF GOST) samples are subjected to laser deposition using a pulsed Nd:YAG laser. A nickel-based material (0.02C–73.8Ni–2.5Nb–19.5Cr–1.9Fe–2.8Mn) is employed for laser deposition. After laser deposition, the samples are subjected to heat treatment at 400°C for 5 h, 600°C for 1 h, 800°C for 1 h, and 1000°C for 1 h. The microstructure, the phase composition, and the microhardness of the deposited layer are studied. The structure of the initial deposited layer has relatively large grains (20–40 μm in size). The morphology is characterized by a cellular–dendritic structure in the transition zone. The following two structural constituents with a characteristic dendritic structure are revealed: a supersaturated nickel-based γ solid solution and a chromium-based bcc α solid solution. In the initial state and after heat treatment, the hardness of the deposited material (210–240 HV0.1) is lower than the hardness of the base material (400–440 HV0.1). Only after heat treatment at 600°C for 1 h, the hardness increases to 240–250 HV0.1. Structure heredity in the form of a dendritic morphology is observed at temperatures of 400, 600, and 800°C. The following sharp change in the structural state is detected upon heat treatment at 1000°C for 1 h: the dendritic morphology changes into a typical α + γ crystalline structure. The hardness of the base material decreases significantly to 160–180 HV0.1. The low hardness of the deposited layer implies the use of the layer material in limited volume to repair the forming surfaces of dies and molds for die casting. However, the high ductility of the deposited layer of the nickel-based material is a prerequisite for a high stability under thermocycling loading conditions.

The structure and fracture behavior of a layer of maraging alloy deposited by laser surfacing on steel 3Kh3M3F is studied in the initial condition and after precipitation hardening at 550 and 600°C. Microhardness is measured in layer cross sections, and fractures after surfacing and aging are analyzed in an electron microscope.

High-temperature gas corrosion of steel X6CrNiMoTi17-12-2 (1.4571) used for internal structure components of chemical reactors is studied. The condition of individual regions of the structure in various stages of damage is investigated.

Amorphous/nanocrystalline SiO x / CdSe , GeS 2 / CdSe , SiO x / ZnSe and Se / CdSe amorphous multilayers (MLs) were grown by consecutive physical vapour deposition of the constituent materials at room substrate temperature. A step-by-step manner of deposition was applied for the preparation of each layer ( 2 – 10 nm thick) of MLs. Surface morphology has been investigated by atomic force microscopy (AFM) in order to get information about ML interfaces. For a scanned area of 3.4 × 4 μ m 2 SiO x / CdSe and GeS 2 / CdSe MLs showed surface roughness which is around three times greater than the roughness of SiO x / ZnSe MLs. This observation has been connected with effects of both film composition and deposition rate. For a scanned area of 250 × 250 nm 2 the roughness determined in all MLs displayed close values and a similar increase with the ML period. The latter has been related to the flexible structure of amorphous materials. The AFM results, in good agreement with previous X-ray diffraction and high resolution electron microscopy data, indicate that the application of step-by-step physical vapour deposition makes possible fabrication of various amorphous/nanocrystalline MLs with smooth interfaces and good artificial periodicity at low substrate temperatures.

In this paper, we present a new numerical model, in which both the thermal and the electromagnetic aspects of the over-critical current regime of HTS materials are taken into account. The electromagnetic and thermal equations have been implemented in finite-element-method (FEM) software in order to obtain a novel, closer to reality model for investigating the behaviour of the superconductor when the current exceeds $I_{c}$. This model has been applied for studying the behaviour of strip lines of an YBCO/Au FCL with a sapphire substrate. Simulations with currents largely exceeding $I_{c}$ have been performed, showing that the total current limitation occurs only when the temperature dependence of the electrical parameters is taken into consideration. Such modelling can replace experiments with currents far exceeding $I_{c}$ which may damage or destroy the studied sample or HTS device.

The magnetic field profile on the surface of Bi-2223/Ag tapes has been dynamically measured across the width of the samples. The experimental technique uses a Hall-probe array with 7 sensors connected to a multiple channel lock-in amplifier especially programmed for fast and synchronous data acquisition measurements. The speed of the system is high enough to measure real-time profiles with 7 probes and 50 Hz sine current through the sample. A numerical method to estimate the current distribution inside the tapes using the measured field profile data is proposed. The inverse problem has been solved using certain assumptions on the current distribution in the superconductor. Validation of the results has been done by comparison with finite element method simulations.

The performance of HTS devices is strongly influenced by local values of the current and field distributions. In this paper, we investigate the influence of the magnetic field and the geometrical configuration on the loss behavior of a 200 kVA FCL prototype, composed by Bi-2223/Ag tapes wound around a cylindrical support. The investigation is performed by means of finite element computations, with the use of an axisymmetric 2D A-V formulation for taking into account the cylindrical geometry. The electrical behavior of the superconductor is described by means of a B-dependent E-J power-law relation, derived from experimental measurements with a field of different orientation. Several geometrical configurations are analyzed and compared, in order to find the ones with the lowest AC loss.

Geometrical aspects of the design of fault current limiters (FCL) have a great impact on their performances. Recently, the University of Geneva have made certain optimizations by splitting the FCL into many small dissipative lengths in order to achieve a distributed transition along the device. For this paper, we have performed new 3D finite element method (FEM) simulations for studying the behavior of strip lines of a YBCO/Au FCL in an AC nominal use (sinusoidal current at industrial frequency) up to 3 I/sub c/. The very large aspect ratio of the device needs a particular attention to the modeling and meshing process. The numerical results show that presence of sharp corners can influence the performance of the device. Due to the high value of the electric field in these areas, the local losses are much higher than in the case of smooth corners, and this may lead to burning and cracking the wafer. Irreversible damage experiments have confirmed these locations. In this paper we proposed new geometries, taking into account the length of the connecting path and the corners optimization in order to decrease the risk of very high localized losses in the meander.

In this paper, the effects of the magnetic self-field on the transport properties of a multilayer high-T/sub c/ superconducting (HTS) cable are investigated by means of two-dimensional finite-element method (FEM) simulations. Analyzed is a three-layer HTS cable, but the developed methods can be used for a different number of layers. The superconductor is described by the nonlinear power-law relation E=E/sub c/(J/J/sub c/)/sup n/, where the parameters J/sub c/ and n depend on the magnetic field experienced by the material. This dependence decreases the global transport capacity of the superconductor, enhancing its AC losses. It is shown that, especially at high transport currents, the AC losses are considerably higher than in the case where the dependence on the magnetic field is neglected. A simple electrical model, considering the cable from macroscopic point of view, has been proposed for finding the optimal winding pitches, leading to a uniform current repartition. The use of this electrical model allows to overcome the difficulties of direct three-dimensional FEM computations. In addition, the rapidity of solutions by the electric model gives the possibility of testing quickly many geometrical configurations in order to find the ones leading to an even current repartition. This optimization process would not be possible with detailed FEM simulations.

For describing the E-J relation of high-Tc superconductors (HTS) in power applications, where the applied current I is generally limited by Ic, the critical state model, a piecewise linear generalization, or a simple power-law of the type E=Ec(J/Jc)^n are most often used. The power-law cannot be used for modelling the E-J relation with I>>I_c due to the unbound exponential increase of the electric field for currents above Ic, while in reality the non-linear HTS resistivity is limited by its normal state value. This paper presents a modified E-J model for describing the V-I characteristic of HTS tapes with applied currents largely exceeding Ic. This model is based on the power-law in combination with a parallel metallic branch and has a limited resistivity - the HTS one in the normal state. It can be used for black-box modelling of superconductors in a unlimited current range, as well as for numerical modelling of superconducting devices, which can be operated at currents far exceeding Ic; for example fault-current limiters or cables with over-critical current excursions. The model has been tested in a simple numerical implementation and the modified power-law has been implemented in finite element method simulations. It is shown that for bulk material with currents above 1.3-2Ic$ (depending on the n-value), the usual power-law results in excessive AC loss estimation.

The current repartition inside a HTS cable is very important for determining its AC losses and can be influenced by the uniformity of several parameters, either linked to the physical properties of the individual tapes (critical current Ic and power index n) or due to the manufacturing process (contact resistance). This work investigates the importance of the non-uniformity of these parameters for a manufactured 16-tape straight superconducting cable by means of finite element method (FEM) simulations. The utilized non-linear E-J model includes the anisotropic dependence of the critical current density and the power index on the local magnetic field. It is shown that the non-uniformity of the cable parameters influences the behaviour of the individual tapes, but not that of the whole cable. The utilized FEM model has been validated by a comparison with electrical measurements of the cable AC losses, as well as with the results of another simpler numerical model, which considers the cable from the macroscopic point of view.

The finite element method has been employed in order to simulate the behavior of a HTS cable for transport current applications. The E-J model includes an anisotropic dependence of the critical current density J/sub c/ and power index n on the local magnetic field, whose magnitude is nonnegligible and determines the effective critical current of the cable. The cable consists of four electrically insulated layers, each of them composed by 20 superconducting tapes, providing a total critical current of about 4 kA. In order to obtain a uniform repartition of the current among the layers, a sufficiently high contact resistance has been inserted in the electric circuit. The ac losses and the field distribution have been computed. A comparison is also made with a simple electric model of a HTS cable.

This paper presents results from numerical modelling of non-twisted multifilamentary Bi-2223/Ag conductors with various geometry and filament arrangement. New anisotropic models of Jc(B) and n(B) have been employed in finite element method simulations under different operating conditions – with applied AC transport current, in external parallel and perpendicular AC magnetic field, and with combined current and field of varying orientation. AC losses, as well as current and magnetic flux densities in square and round Bi-2223/Ag wires with different filament arrangement have been calculated and compared to those of a 7-filamentary tape. The notion of effective Ic(B) in transport current applications is introduced and discussed. It is demonstrated that the shape factor of the conductors and the orientation of the local magnetic field with respect to the individual filaments are of primary importance for the AC loss magnitude in different applications. Outlined are the advantages of using conductors with specific filament configuration for a given application.

This paper presents results from numerical modelling of BSCCO conductors performed with finite element method software. The AC losses are calculated and compared for conductors of different geometry and aspect ratio––an elliptical tape with anisotropic Jc(B) and a round wire with isotropic Jc(B), in external magnetic field of various angles. The difference in the losses of the wire and the tape is found to be significant and depends on the applied field's magnitude and orientation. Also studied is the effect of the lateral Jc distribution along the width of a 37-filamentary tape. The AC losses in each filament are calculated and compared. Simulations with transport current only, as well as with applied AC perpendicular or parallel fields have been made for a model with constant Jc and models with increasing and decreasing Jc towards the edges of the tape.

In typical power applications, Bi-2223 conductors carrying AC current will be subjected to external magnetic fields whose orientation and conductor's geometry are of major significance for the AC loss magnitude. This paper investigates the influence of the geometry and aspect ratio of nontwisted Bi-2223 conductors in reducing the AC loss for such applications. A numerical model of high-T/sub c/ materials has been used in finite-element-method (FEM) simulations. The model incorporates power-law E-J characteristics with J/sub c/ and n defined by both parallel and perpendicular local magnetic field components. It allows computations of field and current distributions with transport current and/or applied field of any orientation. Monofilamentary tapes of rectangular and elliptical geometry with anisotropic J/sub c/(B), as well as square and round wires with isotropic J/sub c/(B) have been used for simulations under various operating conditions. A comparison between AC losses, magnetic field, and current distributions in the tapes and wires is presented.

Different measurement techniques have demonstrated that due to better alignment during the manufacturing process, the central filaments in multifilamentary Bi-2223 tapes have higher critical current density than the outer filaments. A numerical model of non-twisted tapes has been used in Finite-Element-Method simulations. The model incorporates non-uniform lateral Jc distribution in accordance with direct Ic measurements, made along the width of a Bi-2223 tape. Two types of simulations are performed on 7 and 19-filamentary tapes with applied transport current – one with constant Jc in all filaments, and another with a Jc(x) dependence. The current distribution and AC loss in each filament are numerically calculated and compared. It is demonstrated that the current density distribution and power dissipation vary considerably in the different filaments, which is due to the position of the filament with respect to the edge of the tape and the different Jc values along the width.

Different finite-element method (FEM) formulations have been developed in order to model the electromagnetic behavior of type-II superconductors. This paper presents a comparison between simulations with A-V formulation models implemented in two FEM software packages (FLUX2D and FLUX3D) and a numerical method based on analytical model for superconductors in applied magnetic field. These models can be used for superconductors with complex geometry and power-law current-voltage characteristics. Simulated is a 37-filamentary tape with applied transport current in self-field and alternating current (ac) magnetic field parallel to the wide side of the tape. A good agreement is found between the ac-loss and current distributions obtained with the different models.

Mono and multifilamentary HTS tapes exhibit non-negligible AC loss in self-field and considerably higher losses in the presence of external magnetic field. The effect of the conductor’s geometry on the AC loss has been investigated in this paper. The nonlinear electromagnetic properties of the superconducting material are expressed with a B-dependent E-J power law and are implemented in Finite Element Method commercial software. The critical current density and the power index n dependence on B are obtained from DC measurements of a real Bi-2223 tape. AC loss comparison between monofilamentary conductors of rectangular, elliptical, square and round geometry has been performed in self-field and applied external perpendicular magnetic field. The areas of the cross-section and the superconducting-core-to-Ag ratio have been kept constant in the simulations. To complement the AC loss analysis, the distribution of the current density and the magnetic field of the different geometries are presented.

A digital lock-in amplifier has been used to perform V-I time series acquisition when transport currents with amplitude above Ic are driven through Bi-2223 tapes. The current waveform is triangular, sinusoidal or with arbitrary shape, and is applied for several consecutive cycles. The generator frequencies are selected to be 0.05, 0.1, 0.5, 1, 10 and 59 Hz. The amplitude of the applied current is varied from 2 to 20 times the value of Ic. The invariance of the V-I curves during several consecutive cycles and the resistive behaviour of the tapes in the over-Ic regime show that Bi-2223 tapes have very good stability to such type of transport current perturbations.

We use a dual channel digital lock-in to perform electrical measurement of AC losses at power frequencies. A DC magnetic field between 2 and 400 mT is applied with a varying angle from parallel to perpendicular to the tape surface, thus having a complete view of the loss behavior under DC applied field. Furthermore, the same experimental layout is used to acquire time series of current and voltage across the sample. Using a triangular input current, we measure and average the voltage, which then is fitted to a power law (I/I/sub c/)/sup 11/. The measurements are repeated for the mentioned magnetic field and angle domain to give the dependencies of I/sub c/ and n with magnetic field and angle. For device modeling purposes, we can then express a phenomenological law giving I/sub c/ and n as a function of the applied magnetic field's intensity and direction.

The a.c. self-field loss in Bi(2223)Ag sheathed tapes with different number of filaments has been measured between 59 and 2500 Hz by means of a dual lock-in amplifier. Due to the wide frequency range of the measurements we have been able to dissociate quantitatively the different self-field loss contributions: hysteretic, eddy current and resistive loss (near Ic). This is an important advantage compared to single frequency measurements where such loss dissociation is only qualitative. The hysteresis losses of the different tapes fall between Norris’ predictions for elliptical and strip cross section. The relative weight of eddy current loss is found to be inversely proportional to the current ratio – the higher i, the less is their contribution. Frequency independent resistive loss due to flux creep is observed for high currents at low frequencies; this loss becomes quickly negligible with the increasing frequency.

The a.c. self-field loss in Bi-2223 Ag and Ag-alloy sheathed tapes with different number of filaments has been measured in the range 59-2500 Hz by means of a dual lock-in amplifier technique. We have been able to dissociate quantitatively the different self-field loss contributions: hysteretic, eddy current and flux-creep resistive loss (near Ic) due to their different frequency dependence and the wide frequency range of the measurements. The relative weight of eddy current losses is found to be inversely proportional to the applied current ratio – the higher Ip/Ic, the less is their contribution. Shown are the frequency limits, beyond which eddy current loss has a significant and afterwards a governing contribution to the total a.c. loss in self-field. The distribution of power dissipation in the metal sheath is obtained by software simulation. A comparison has been made between the measured, simulated and theoretically calculated eddy current loss. Investigated is the effect of the sheath geometry and resistivity in reducing the eddy current loss in the measured and simulated tapes.

Plasma-arc surface treatment is a rather simple and effective method for hardening steels. The increase in the resistance to external effects depends on the treatment parameters, the composition of the treated alloy, its initial structure, and the preliminary and post-heat treatment. The present work is devoted to the effect of the regime of plasma-arc surface treatment of steels with different initial structures on the proportion and extent of the strengthened layers, the distribution of the phase and structural components in them, and the wear resistance.

Osteoporosis is a disease in which the mineral density of bone is reduced, its microarchitecture disrupted, and the expression profile of non- collagenous proteins altered. Normal fracture treatment is a complicated, multistage process, involving different cellular events and regulated by local and systematic factors. The objective of this study was to develop bio- active nanostructured materials, in both acellular and autologous cell-seeded forms to enhance bone fracture fixation and healing thought creating highly porous structures which will promote osteogenesis. The approach to develop highly effective hydrogels for counteracting the effects of osteoporosis followed different ways: (a) synthetic and biological polymer chemistry, by using a thermally gelling polymer and nanodiamonds (ultradisperse diamond UDD) (b) experiments with cell models (endothelial progenitor cells EPC). Our investigations demonstrated that in vitro EPC transformation to osteo- blasts was enhanced in the presence of a osteoprogenitor medium and UDD. These results provided initial evidence that synthetic nanomaterials may exhibit certain properties that are comparable to natural one, and nano- material architecture may serve as a superior scaffolding for promoting EPC transformation and biomineralization.

Practical applications of YBCO coated conductors (CC) involving superconducting coils will utilize tapes packed together in an arrangement resembling a vertical stack. In such configuration there is an important electromagnetic interaction between the tapes, which strongly influences the loss characteristic of the device.In the presence of an external magnetic field, the losses are reduced compared to an isolated tape because of the reduced aspect ratio of the conductor and, at least for low fields, because of an effective screening of the central part of the stack. On the contrary, in the case of AC transport current, the losses tend to increase due to the enhancement of the local field caused by the interaction of the self-field produced by neighboring tapes. In practical situations the conductor is usually subjected to both transport current and magnetic field, so that there is a trade-off between the two effects.In this paper we investigate, both experimentally and by means of finite-element method calculations, the ac loss behavior of a stack composed by a finite number of tapes in different working conditions, and we compare the AC losses to the ones of non-interacting tapes in order to determine if the use of stacked tapes is advantageous from the point of view of power dissipation.

The paper presents studies on the microwave properties of two types of polymer composites based on acrylic resin and polyurethane with nanosized magnetic (magnetite) and dielectric (carbon) fillers. The microwave (MW) absorption was measured at 9.4 GHz, while the dielectric and magnetic properties were investigated in the frequency range 1-18 GHz. Promising MW absorption properties were observed for nanostructured filler applications in comparison with the traditional MW absorbers.

A three-dimensional (3-D) numerical modeling technique for solving problems involving superconducting materials is presented. The model is implemented in finite-element method software and is based on a recently developed 3-D formulation for general electromagnetic problems with solid conductors. It has been adapted for modeling of superconductors with nonlinear resistivity in 3-D, characterized by a power-law E-J relation. It has first been compared with an existing and verified two-dimensional (2-D) model: Compared are the current density distribution inside the conductors and the self-field ac losses for different applied transport currents. Second, the model has been tested for computing the current distribution with typical 3-D geometries, such as corner-shaped and twisted superconductors. Finally, it has been used with two superconducting filaments in the presence of external magnetic field for verifying the existence of coupling currents. This effect deals with the finite length of the conductors and cannot be taken into account by 2-D models.

The use of HTSC tapes as main components in future power applications requires better understanding of their AC loss behaviour. Previous studies have lead to conclusions that eddy current loss is a significant loss factor at high frequency in self-field. In this paper we present a Finite Elements Method electromagnetic simulation of the current density and magnetic field distribution in the tape for 59Hz and 1kHz. The Ac losses due to eddy currents in the silver sheath are calculated for a mono and multicore tape. To carry out the electromagnetic simulation we have characterized the electric and magnetic properties of the superconductor using a simple model of a Bi2223 tape.

Thin films of SiO x have been prepared on quartz or c-Si substrates by thermal evaporation of SiO in vacuum and post-annealed at 1373 K in an argon or hydrogen atmosphere. High-resolution electron microscopy has shown the existence of silicon nanocrystals in the annealed films, and this result has been confirmed by Raman scattering. Photoluminescence has been observed from annealed films and attributed to radiative recombination in Si nanocrystals. Its intensity is appreciably higher upon annealing in Ar than in H2. It is shown that substrates strongly affect the Raman scattering from Si nanocrystals in nc-Si–SiO2 thin films with low filling factors.

Polymer nanocomposite materials have attracted increasing attention because of their unique optical properties. Of practical interest is the controllable increase in the refractive index (RI) values of the polymer nanocomposite materials by using nanoparticle inclusions with high refractive index values. This paper presents a study of the optical characteristics of polymer nanocomposites with diamond and titanium dioxide (titania) spherical nanoparticles with different diameters (2 nm and 15 nm) and very close refractive index values − 2.50 and 2.42, respectively. The investigated samples are with different concentration of the particles varying from 0 wt% to 3 wt.%. The refractive indices are measured by a laser refractometer at two wavelengths, 532 nm and 632.8 nm. The results obtained show that the RI increases with the increase in the concentration of the inclusions of titania and diamond in the PVA matrix.

The dielectric function of polymer nanocomposites is examined in a small filling factor approximation (SFFA). The linear concentration dependence on SFFA is experimentally confirmed by refractometric investigations of PVA thin films doped with titania and diamond nano-sized particles.

1. By plasma surface fusion in gray irons with lamellar and spheroidal graphite it is possible to obtain a hardened case with a hardness of not less than 580–600 HV and a structure characterized by high inhomogeneity, which consistas basically of quasiledeburite, cementite, carbides, martensite, residual austenite, bainite, sorbite, and graphite in various ratios and quantities depending upon the form of the iron and the treatment conditions. 2. The best quality of hardened layer is observed in irons with spheroidal and lamellar graphite with a carbon equivalent of 3.5–3.7 with a case thickness of not more than 1.2–1.5 mm, a preheat temperature of 400°C, and a ratio of vp/tp=(10–20)·10−6 cm/(sec·deg).

The nonlinear behavior of high temperature superconductors (HTS) is often modeled by an E-J power law in order to describe their electromagnetic properties. This paper presents AC loss calculations in HTS tapes, performed by means of FEM commercial software using the A-V method. The implemented nonlinear model of the HTS tapes takes into account the B-dependence of the critical current density J/sub c/ and the power index n. The expressions for J/sub c/(B) and n(B) are obtained from electrical measurements of a Bi-2223 tape under applied DC magnetic field. Numerical simulations of HTS tapes under different experimental conditions have been performed, i.e. the application of a transport current and/or AC external perpendicular magnetic field at 59 Hz. A comparative analysis of AC loss is then presented where J/sub c/ and n are maintained either constant or B-dependent. The combined J/sub c/(B) and n(B) formulation leads to a better understanding of HTS electromagnetic behavior, especially when a perpendicular magnetic field is applied.

The AC loss performance of two BSCCO and two YBCO conductors of different geometry, characterized by the same self-field critical current of 150 A, is analysed and compared quantitatively. The comparison is made using the finite-element method with a non-linear B-dependent E-J relation. A new shell-region model is utilised for the simulations of thin YBCO strips. Different AC working conditions are simulated: self-field, applied external field, and combined transport current and external perpendicular field application. Magnetic field and current density profiles are investigated in order to illustrate the reasons for the loss difference in the conductors. Depending on the application, the advantages of using BSCCO or YBCO conductors with specific geometry are outlined.

This paper presents results from numerical modeling of nontwisted multifilamentary Bi-2223/Ag conductors with various geometry and filament arrangement. Anisotropic models of J/sub c/(B) and n(B) have been employed in finite element method simulations under different operating conditions - with applied ac transport current, in external parallel and perpendicular ac magnetic field, and with combined current and field of varying orientation. AC losses and current distributions in square and round Bi-2223/Ag wires with different filament arrangement have been calculated and compared to those of a 7-filamentary tape. It is demonstrated that the shape factor of the conductors and the orientation of the local magnetic field with respect to the individual filaments are of primary importance for the ac loss magnitude in different applications. Outlined are the advantages of using conductors with specific filament configuration for a given application.