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The hysteresis description advanced by Harrison is static in nature. On the other hand, it seems crucial for some applications to consider how the dynamic effects due e.g. to eddy currents in conductive materials affect the shapes of modeled hysteresis loops. In the paper two possible model extensions are proposed. The approach based on the introduction of an additional term in the so-called effective field yields a better accuracy in comparison to the extension using a term related to relaxation time. • The quasi-static hysteresis description based on positive feedback mechanism is extended to the dynamical case. • Two possible model extensions are compared. • The approach based on the introduction of a damping term into the so-called effective field yields a better accuracy. [ABSTRACT FROM AUTHOR]

Monitoring and controlling the position of fibre optics connectors is a very important issue. Both autonomy and remote control of such a system are very desired and therefore energy independence must be provided. In this paper the design of an optical power supply system is given. A new idea of using theWDMtechnique in a power supply block is investigated. The electric power provided by a photovoltaic power converter and by a boost converter is shown. Moreover, in this paper the complete examination of efficiency of the system with different illuminations is given. The maximal output power of the system is 24.02 mW and the time required to identify a single fibre connector is tCYCLE = 0:65 s. [ABSTRACT FROM AUTHOR]

Purpose The purpose of this paper is to develop identification system for fiber optic connectors in passive distribution cabinets. The system should have alternative power supply and wireless communication unlike the identification systems commercially available, which will make the system fully autonomous.Design/methodology/approach Detailed project and realization of real demonstrator of fully autonomous identification system. After the realization of the demonstrator, its optimization was performed.Findings It is possible to build fully autonomous identification system which requires 15.6 mJ energy to perform one cycle of identification process. Moreover, it is possible to use the alternative power method to supply this system.Originality/value Fully autonomous identification system of fiber optic connectors with alternative power supply and wireless communication. [ABSTRACT FROM AUTHOR]

Magnetic properties of hard magnets are currently attracting a great deal of attention. In the paper, the modified Harrison model was used to describe the saturating hysteresis loops of three praseodymium–dysprosium ribbons that differed in their chemical composition and processing conditions. Microstructural studies (TEM and diffraction patterns) were performed for the ribbons under consideration. The Harrison model incorporates a number of physically tangible concepts such as the anhysteretic curve, bifurcations, and bi-stability. The modification of the original approach consisted of adding an additional degree of freedom in the modeling by freeing the restraints present in the original version, in which both coercivity and remanence are functions of temperature only. [ABSTRACT FROM AUTHOR]

The paper concerns the design and development of large electric energy storage systems made of lithium cells. Most research advances in the development of lithium-ion battery management systems focus solely on safety, functionality, and improvement of the procedures for assessing the performance of systems without considering their energy efficiency. The paper presents an alternative approach to the design and analysis of large modular battery management systems. A modular battery management system and the dedicated wireless communication system were designed to analyze and optimize energy consumption. The algorithms for assembly, reporting, management, and communication procedures described in the paper are a robust design tool for further developing large and scalable battery systems. The conducted analysis of energy efficiency for the exemplary 100S15P system shows that the energy used to power the developed battery management system is comparable to the energy dissipated due to the intrinsic self-discharge of lithium-ion cells. [ABSTRACT FROM AUTHOR]

Lithium-ion battery systems are becoming a major component in numerous applications. The thermal behaviour of cells should be monitored for many reasons. In this paper, the investigation of the energy balance for lithium-ion battery system is described. The electrothermal model allows to describe heat generation and heat dissipation processes in all components of a battery pack (BP). Moreover, this model can be easily adapted for bigger, modular battery systems, since the primitive in the proposed model is a single cell. A method to determine the energy balance through experimental investigations and to validate the model is also proposed. Four types of BPs with sixteen cylindrical 18650 lithium-ion cells were tested. The influence of both busbar material and the presence of heatsinks on the BP thermal conditions was investigated. The results show that the heat accumulated in cells can be decreased by 20% and the cell temperature lowered by 8 °C if additional elements are used in a BP. [ABSTRACT FROM AUTHOR]

The topic of this paper is modeling based on Hamiltonian spin interactions. Preliminary studies on the identification of quasi-static magnetizing field in a magnetic system were presented. The random-field Ising model was then used to simulate the simplified ferromagnetic structure. The validation of algorithms and simulation tests were carried out for the 2D and the 3D model spaces containing at least 106 unit cells. The research showed that the response of a slowly driven magnetic system did not depend on the external field sweep rate. Changes in the spatial magnetization of the lattice were very similar below a certain rate of the external field change known as the quasi-static boundary. The observed differences in obtained magnetization curves under quasi-static conditions stemmed from the random nature of the molecular field and the avalanche-like magnetization process [ABSTRACT FROM AUTHOR]

• The measurements of hysteresis loops and power losses were carried out for the LaFe 10.92 Co 1.08 Si 1.2 alloy sample. • The influence of DC-biased magnetic field on dynamic hysteresis loop and power losses is studied. • The excitation field without DC bias component results in overestimated energy losses. The paper presents an experimental study of magnetic properties of the LaFeCoSi alloy near the magnetic phase transition at the Curie temperature of 306 K. The biased magnetizing field complies with the real magnetization of active magnetic regenerators, whereas the standards for testing soft magnetic materials recommend the approach based on the bipolar magnetizing field. The influence of the DC-biased magnetic field on dynamic hysteresis loops and power losses was studied. The investigations confirmed a significant drop of power losses under biased magnetization and proved that the impact of the time of the magnetizing field switching between the isomagnetic states is critical, as far as the field distribution inside the sample and the magnitude of magnetic losses are concerned. [ABSTRACT FROM AUTHOR]

• The scaling analysis of phase transitions in magnetocaloric alloys (MCA) is validated. • The scaling exponent values change significantly near phase transition temperatures. • The scaling exponent characteristics indicate an additional phase transition at 315 K. • This is an alternative method for determining phase transition temperatures in MCA. • The method allows one to determine hardly noticeable phase transitions. The paper presents magnetization measurements and the scaling analysis of related power loss for a high-temperature magnetocaloric alloy (T C = 330 K). The measured hysteresis loops show anomalous behaviour near the temperature of 315 K, which may indicate the occurrence of additional phase transition. Power losses measured in different temperatures are analyzed using the scaling theory in order to determine the universal curves and the scaling exponents. The temperature dependence of scaling exponents confirms the existence of another phase transition at the temperature of 315 K, associated with an additional metallic phase in the alloy. [ABSTRACT FROM AUTHOR]

In the present paper, the effect of temperature on the shape of magnetic hysteresis loops for a magnetocaloric composite core was studied. The composite core, based on La(Fe, Mn, Si)13-H, was set up using three component disks with different Curie temperatures. The magnetic properties of the components and the outcome composite core were determined using a self-developed measurement setup. For the description of hysteresis loops, the phenomenological T(x) model was used. The presented methodology might be useful for the designers of magnetic active regenerators. [ABSTRACT FROM AUTHOR]

Abstract: The paper presents a press-pack package integrated with a microchannel cooling system, which is a new thermal solution for power devices, e.g. diodes. In comparison with conventional solutions enforcing the use of either an air cooling system or a liquid one, the novel package is characterised by considerably smaller dimensions, lower weight and significantly higher thermal performance. The conducted measurements of the manufactured model showed that a thermal resistance of 0.0182K/W can be obtained for an allowable pressure drop for electronic applications. [Copyright &y& Elsevier]