Depending on their other constituent elements, Fe-based amorphous materials can exhibit good soft magnetic properties. By determining the directional coefficient b for the relationship of mu M-0(mu H-0)(1/2) according to the best linear fit, it is possible to determine the parameter of spin wave stiffness D-spf. This parameter, amongst others, is related to the distribution of magnetic atoms around the central atom, which is reflected in the value of saturation magnetisation. This work has examined the structure of specially prepared alloy samples and analysed the influence of the spin wave stiffness parameter on the value of saturation magnetisation. Three alloys with different constitutions, based on the Fe matrix, were analysed.

The phenomenon of magnetic viscosity can be observed when measuring losses on remagnetization.During magnetization of a ferromagnetic with alternating current, apart from the losses caused by magnetization and eddy currents, an additional component can be observed, which is referred to as additional losses.Such losses can be divided into two groups, i.e., strongly and weakly dependent on frequency and temperature.The paper presents tests of losses in the frequency range from 50 to 1000 Hz.Exact calculations of the share of additional losses caused by magnetic viscosity were made.

The amorphous state is characterized by metastability, which results in structural relaxation even at low temperatures. These relaxations contribute to the magnetic properties of amorphous alloys, such as the value of the coercive field, losses from hysteresis or magnetic susceptibility. In amorphous materials, as opposed to crystalline ones, the description of relaxation phenomena is difficult due to the fact that these processes are described by the activation energy spectrum and occur in a wide temperature range. The paper presents the results of the analysis of migration processes based on the adopted H. Kronmiffier model, in which the reorientation of atoms takes place in areas of reduced volume called free volumes.

One of the characteristics of the amorphous state is metastability, which results in structural relaxation even at low temperatures. These relaxations contribute to the magnetic properties of amorphous alloys, such as the value of the coercive field, losses from hysteresis and magnetic susceptibility. In amorphous materials, as opposed to crystalline ones, the description of relaxation phenomena is difficult due to the fact that these processes are described by the activation energy spectrum and occur in a wide temperature range. The paper presents the results of the analysis of migration processes based on the adopted H. Kronmiffier model, in which the reorientation of atoms takes place in areas of a reduced volume called free volumes.

Remagnetisation losses are one of the most important performance parameters of materials designed for the production of low-loss transformer cores. Classical Fe-Si alloys are characterised by losses of a few W/kg. However, the crystal structure makes these materials unsuitable for use at high frequencies. The ferromagnetic Fe-based alloys constitute an interesting group of alloys with magnetic soft properties. This group includes alloys from the Fe-Me-B system (where Me is one of the range of transition metals). This study investigates the structure, and losses due to remagnetisation, of bulk amorphous FeYMoNbB-based alloys. It was found that the addition of a small quantity of Nb changes the structure, and the magnitude of the losses. The addition of Nb significantly reduces additional losses; this effect is associated with the changing melt viscosity.

In this work, the structural and magnetic properties of rapidly-cooled alloys Fe60Co10Y5+xZr5-xB20 were investigated. The chemical composition of the alloy and manufacturing parameters were selected to obtain a partially-crystallised structure. The tested nanocrystalline alloys were produced by injection of each liquid alloy into a copper mould. The structure of each alloy was investigated using X-ray diffraction. The diffractogram analysis was performed using the specialist Match! software. The magnetic properties of the alloys were determined on the basis of measurements that were carried out using a vibrating sample magnetometer. The study showed that it is possible, using a single-stage process, to produce an alloy with a nanocrystalline structure containing a significant proportion of an amorphous matrix. It was found that varying the proportions of Y and Zr promoted the creation of different crystalline phases. This fact was related to the physical properties of the elements: the higher value of the negative heat of mixing for Zr with the other alloying components, compared with Y. In the case of the alloy with the higher content of Y, a phase was identified which exhibited so-called "hard-magnetic" properties. The formation of this phase results in a different distribution of Fe atoms, as indicated by a higher value of saturation magnetisation and lower value of the spin-wave stiffness parameter.

The magnetisation process of amorphous materials is similar to that of crystalline materials and consists of four stages. Each step influences the formation of the primary magnetisation curve. By using measurements in the "easy," "intermediate" and "difficult" magnetisation directions, the primary magnetisation curves are obtained, on the basis of which the value of effective anisotropy can be determined. This paper presents the results of tests that were carried out on two amorphous alloys that are based on an Fe matrix. The value of effective anisotropy was related to the spin-wave stiffness parameter.

This paper presents the results of research on the magnetic saturation polarisation, as a function of temperature, for rapidly-cooled iron alloys with an amorphous structure. The rapidly-cooled Fe-based amorphous alloys are characterised by good magnetic properties. The Curie temperature is one of the main parameters that determine the stability of the ferromagnetic properties of such alloys. The tested materials met the assumptions of Heisenberg's theory; therefore, the critical factor, beta = 0.36, was used to determine the Curie temperature. It was found that both of the tested alloys have one Curie temperature pertaining to the amorphous matrix - which proves their effective homogenisation.

The paper presents the results of tests carried out on samples of FeCoB-based alloys.The samples were produced by a technique involving the injection of each liquid alloy into a copper water-cooled mould.The investigated materials are characterised by much better properties than their crystalline counterparts with the same chemical composition.It has been shown that the cooling rate has a significant impact on the magnetic properties of the produced alloy.Alteration of the production parameters of FeCoB alloys has a decisive influence on the resulting properties of these alloys.The research has revealed evidence that changes in the structural characteristics are related directly to changes in the magnetic properties.

Department of Physics, Częstochowa University of Technology, al. Armii Krajowej 19, 42-200 Częstochowa, Poland Advanced Engineering Centre, School of Computing, Engineering and Mathematics, University of Brighton, Cockcroft Building, Lewes Road, Brighton, BN2 4GJ, UK Gheorghe Asachi Technical University of Iasi, Faculty of Materials Science and Engineering, Blvd. D. Mangeron 41, 700050, Iasi, Romania Center of Excellence Geopolymer & Green Technology (CEGeoGTech), School of Materials Engineering, Universiti Malaysia Perlis, 01000 Kangar, Perlis, Malaysia

As part of this work, structural investigations were carried out on rapidly-cooled alloys with the following chemical compositions: Fe60Co10Y8-xNi2+xB20 (where x = 0, 1). X-ray diffraction studies confirmed that the tested materials have an amorphous structure. This structure is characterized by absence of long-range atomic order, in the contexts of angularity and periodicity. Therefore, these materials should exhibit different magnetic properties, compared with those of their crystalline counterparts. In the electrical power and electronics industries, there is a constant demand for materials with better and better properties. The main considerations of applicability are economics and environmental protection. The deciding parameter, determining the usefulness of ferromagnetic alloys in electrotechnical devices and considering economics and ecology, is their low losses on remagnetization. For the produced alloys, described in this paper, a series of loss tests for remagnetization at different frequencies was carried out. The losses for remagnetization-pertaining to the hysteresis loop-and additional losses were determined.

Department of Physics, Częstochowa University of Technology, al. Armii Krajowej 19, 42-200 Częstochowa, Poland University of Brighton, BN2 4GJ, Brighton, United Kingdom Gheorghe Asachi Technical University of Iasi, Faculty of Materials Science and Engineering, Blvd. D. Mangeron 41, 700050, Iasi, Romania Center of Excellence Geopolymer& Green Technology (CEGeoGTech), School of Materials Engineering, Universiti Malaysia Perlis, 01000 Kangar, Perlis, Malaysia

The structure of amorphous alloys still has not been described satisfactorily due to the lack of direct methods for observing structural defects. The magnetizing process of amorphous alloys is closely related to its disordered structure. The sensitivity of the magnetization vector to any heterogeneity allows indirect assessment of the structure of amorphous ferromagnetic alloys. In strong magnetic fields, the magnetization process involves the rotation of a magnetization vector around point and line defects. Based on analysis of primary magnetization curves, it is possible to identify the type of these defects. This paper presents the results of research into the magnetization process of amorphous alloys that are based on iron, in the areas called the approach to ferromagnetic saturation and the Holstein-Primakoff para-process. The structure of a range of specially produced materials was examined using X-ray diffraction. Primary magnetization curves were measured over the range of 0 to 2 T. The process of magnetizing all of the tested alloys was associated with the presence of linear defects, satisfying the relationship Ddi p < 1H. It was found that the addition of yttrium, at the expense of hafnium, impedes the magnetization process. The alloy with an atomic content of Y = 10% was characterized by the highest saturation magnetization value and the lowest value of the Dspf parameter, which may indicate the occurrence of antiferromagnetic ordering in certain regions of this alloy sample.

Improvised Explosive Devices (IEDs) have claimed many lives during recent wars. The response from military vehicle designers has been to provide more and more armour. However, this may not be the best long-term solution, as, amongst other factors, the weight of the vehicle increases dramatically. Aligning to the trend of more electric vehicles, this paper presents a different approach to tackle this problem which provides better protection for the crew, by removing the driver from the traditional physical location in the vehicle. A solution, such as Steer-by-Wire, leading to Drive-by-Wire crew station, can physically shift the location of the crew in the vehicle, thereby providing better protection against IEDs. This paper describes a procedure for designing such a system; it also describes a representative vehicle platform that has been assembled to demonstrate the proposed system functionality.

The control of modern electrical power systems is, in some respects, limited by traditional analogue control methods. It is recognised that digital control can offer significant advantages in enhancing a power system's closed-loop performance and improve control implementation over traditional analogue methods. In particular, an electrical power system can exhibit optimum performance throughout its operating range and even enhance its operating range through the use of dynamic digital control-coefficients. This paper seeks to describe the process by which a system under continuous-time control can be converted into one which operates with digital control. The aim is to provide an introduction to digital control, based on a design process using the open-loop frequency response of a system. Several problems encountered when designing a digital controller are highlighted; in particular, the effect of the sampling time on the performance of the system. The system performance under digital control is compared to its analogue equivalent, and suggestions are made to minimise the difference between the performances of the two types of implementations.

This paper presents the results of investigations into the microstructure and magnetic properties of Fe86Zr7Nb1Cu1B5, Fe82Zr7Nb2Cu1B8 and Fe81Pt5Zr7Nb1Cu1B5 alloys. The alloys were investigated in their as-quenched state, in the form of thin ribbons with approximate dimensions as follows: width 3 mm and thickness 20 mu m.The investigations were performed utilizing Mossbauer spectrometry and X-ray diffractometry. Also, an evaluation of the low-field magnetic susceptibility and measurements of the magnetization versus temperature and magnetizing field were performed.

This study investigates whether feedforward neural networks with two hidden layers generalise better than those with one. In contrast to the existing literature, a method is proposed which allows these networks to be compared empirically on a hidden-node-by-hidden-node basis. This is applied to ten public domain function approximation datasets. Networks with two hidden layers were found to be better generalisers in nine of the ten cases, although the actual degree of improvement is case dependent. The proposed method can be used to rapidly determine whether it is worth considering two hidden layers for a given problem.

In this paper, the results of structural and magnetic investigations are presented for the following amorphous alloys: FeMeMoCrNbB (where Me = Ni or Co). The structural investigations were performed using X-ray diffractometry. It was found that the investigated samples were amorphous in the as-cast state. The magnetisation was measured within magnetic fields ranging from 0 to 1 T using a vibrating sample magnetometer. Investigation of the "magnetisation in the area close to ferromagnetic saturation" showed that the magnetisation process in strong magnetic fields is connected with the rotation of magnetic moments in the vicinity of defects, which are the sources of short-range stresses. Analysis of the high-field magnetization curves facilitated the calculation of the spin-wave stiffness parameter.

Two-hidden-layer feedforward neural networks are investigated for the existence of an optimal hidden node ratio. In the experiments, the heuristic n_1 = int(0.5n_h + 1 ), where n_1 is the number of nodes in the first hidden layer and n_h is the total number of hidden nodes, found networks with generalisation errors, on average, just 0.023 n_h , with very little penalty. Further reductions in search complexity to logarithmic could be possible using existing methods developed by the Authors.

The paper presents the results of structural and magnetic properties and thermal stability for a group of functional materials based on Fe61Co10Zr2.5Hf2.5Me2W2B20 (where Me = Mo, Nb, Ni or Y). Samples were obtained in the form of ribbons using melt-spinning method. The X-ray diffraction patterns of investigated samples confirmed their amorphous structure. Based on the analysis of DSC curves characteristic temperatures: glass forming temperature (Tg), crystallization temperature (Tx) and temperature range of the supercooled liquid ΔTx were determined. Small addition of transition metals elements has strong influence on magnetic and thermal parameters of studied materials. The comprehensive studies revealed that in terms of magnetic properties the Ni-addition resulted in highest reduction in coercivity and anisotropy field.