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The aim of this paper is to present a new relatively simple model of the rotational magnetization process in anisotropic sheets.

The surface of a sample of an anisotropic sheet is divided into an assumed number of specified directions. To each direction a certain hysteresis loop, the so‐called direction hysteresis, is assigned. The parameters of the proposed model are calculated on the basis of such values as the saturation flux density, the residual flux density (remanence), and the coercive force. It is also necessary to take into account the anisotropy constant and also the distribution function of the grains in the sample of the given anisotropic material.

The model of the rotational magnetization process of soft ferromagnetic materials takes into account two fundamental phenomena: the irreversible domain wall movements and the rotations of the flux density vectors from the easy magnetization axes. This model can also be used for the modelling of the axial magnetization process.

The proposed model can be used in numerical calculations of the rotational magnetization in magnetic circuits of electrical machines for any work conditions. However, for the comprehensive calculation of the magnetic field distribution this model should be completed with eddy current equations. Eddy currents influence magnetic field distribution in electric steel sheets.

A new model of the rotational magnetization process in anisotropic sheets is proposed.

The paper presents the analysis of magnetic field that surrounds the power transformer after it has been switched off. The purpose of this paper is to determine the possibility of defining the residual fluxes in the legs of the transformer based on the measurement of this field. It was also intended to determine the type and the location of magnetic sensors.

Numerical analysis of the magnetic field was performed. A three-dimensional model of the transformer’s magnetic core was created in the Flux 3D simulation program. The analysis was concerned with an oil-filled transformer and a dry transformer. The magnetic field of Earth was taken into account.

The research has shown that magnetic induction of the leakage field produced by residual magnetization of the core is comparable to the magnetic induction of the Earth’s field. It was also found that the measurement of the magnetic induction should be performed as close as possible to the core. The interior of the tank turned out to be a convenient space for the placement of the sensors.

The influence of external ferromagnetic objects, and devices generating magnetic field, on the measurement was not considered. It should be taken into account in the future work.

On the basis of the analysis, it was proposed to measure the magnetic induction vector of the leakage field at three points. The sensors should be placed in front of the columns at a position that is half of their height. The measurement can be performed with satisfactory accuracy by sensors located on the surface of the windings.

Current classification of fluxes is typically on the basis of a qualitative process with parameters like residue activity in a water extract or the ability to dissolve copper in a thin mirror film. The capability of quantitatively ranking fluxes by their total reaction capacity and reaction rate with copper oxide would provide valuable data for process design. Results are reported of experiments to establish a standard procedure to measure a flux activity number using a controlled reaction of a measured amount of flux reacted with an excess of a standard metal oxide.

This paper aims to describe some of the European Space Agency (ESA) workmanship standards which are based on industrial practices. Coordination with National Aeronautics and Space Administration (NASA) Centres on workmanship issues is also to be described.

The first ESA (then ESRO) workmanship standard was published in 1972. It applied to the hand soldering of electronic assemblies and became a contractual document, either replacing, or supplementing a vast number of company standards that had existed in European manufacturing companies. Since then some 40 standards related to Materials and Processes have been developed by ESA, the majority of which are to be found in the European Cooperation for Space Standardization (ECSS) series of European standards.

It is shown that, where appropriate, the standards are backed by a number of ESA‐approved skills training schools which provide training courses that result in the certification of operators, inspectors and instructors.

The workmanship standards are periodically revised in order to take into account newly developed technologies, the results of failure analyses (lessons learnt), laboratory and field test results, as well as some particular requests from industry.

The electronics assembly industry has fortunately rediscovered conductive adhesives as the search for lead‐free joining materials and improved performance intensifies. Although these intrinsically clean bonding agents are often first sought for their favourable environmental attributes, many are surprised to find that conductive adhesives can solve old and new problems. Today, new polymer solders for SMT allow low temperature processing, finer pitch assembly and wider processing latitude while providing compatibility with a very much larger range of materials than solder. State‐of‐the‐art adhesives are oxide‐tolerant and absolutely no fluxing or cleaning is required. Adhesives work where solder cannot be used. What's more, polymer‐based solder alternatives can run on existing SMT lines — no new equipment is needed. Z‐axis, or anisotropic, bonding agents are uni‐directional conductive materials that solve fine pitch interconnect problems in several areas. The anisotropics now dominate the flat panel interconnect field. Nearly every LCD and other flat panel display is connected with a polymer adhesive. The Z‐axis adhesives are also beginning to enable high density multilayer circuits and MCMs to be built more effectively. Finally, Z‐axis appears to offer the simplest and most cost‐effective means for flip chip bonding. However, special equipment is required. The paper compares the metallurgical solder joint, the present de facto standard, with the polymer composite bond to highlight similarities and important differences. All types of conductive adhesives are discussed including the latest — Area Array Z‐axis types. Bonding materials, assembly processes and performance are also covered.

Failure analyses of the lead‐free and SnPb solder joints of high‐density packages such as the plastic ball grid array and the ceramic column grid array soldered on SnCu hot‐air solder levelling electroless nickel‐immersion gold or NiAu, and organic solderability preservative Entek printed circuit boards are presented. Emphasis is placed on determining the failure locations, failure modes, and intermetallic compound composition for these high‐density packages' solder joints after they have been through 7,500 cycles of temperature cycling. The present results will be compared with those obtained from temperature cycling and finite element analysis.

The paper presents two new algorithms of controlled switching the power transformer. The purpose of this paper is to obtain formulas that determine the moments of closing of the circuit breaker poles. The study contains projects of control systems for both algorithms.

Mathematical formulas for the time instants of the breaker poles closing were developed on the basis of electric circuit theory and magnetic circuit theory. The presented systems were simulated using a model created in the Alternative Transients Program/Electromagnetic Transients Program software.

Numerical simulations have proved that the shown systems properly perform the controlled switching carried out in accordance with the proposed algorithms. The times of the poles closing were correctly determined and the inrush currents were reduced to a level of the current of unloaded transformer.

The results achieved are better than those shown in the literature. The solutions presented in the literature provide a reduction of inrush current to a value comparable to the rated current of the transformer, which is ten times greater than the no-load current. Additional achievement of the work is the development of analytical formulas that determine the times of the breaker poles closing.

With the advent of the Montreal Protocol, the removal of flux residues from printed circuit assemblies using solvents based on CFC‐113 is no longer an acceptable option. An alternative range of cleaning technologies is being developed and marketed for this purpose, and the aim of this work was to study the efficiency of a variety of these alternative cleaning regimes after IR reflow soldering. The results indicated that: (i) all the cleaning regimes were capable of removing flux and flux residues after standard IR reflow soldering; (ii) as the level of flux contamination under the components increased, the ability of the cleaning regimes to clean the boards decreased; (iii) the cleaning regimes had varying problems in removing the flux residues after the non‐standard (overheat) IR profile processing; (iv) when additional flux is introduced under the components (i.e., non‐standard IR reflow), the delay between soldering and cleaning becomes important; and (v) the cleaning regimes exhibited a wide variation in their ability to clean under components with small stand‐off heights.

Gives introductory remarks about chapter 1 of this group of 31 papers, from ISEF 1999 Proceedings, in the methodologies for field analysis, in the electromagnetic community. Observes that computer package implementation theory contributes to clarification. Discusses the areas covered by some of the papers ‐ such as artificial intelligence using fuzzy logic. Includes applications such as permanent magnets and looks at eddy current problems. States the finite element method is currently the most popular method used for field computation. Closes by pointing out the amalgam of topics.

The paper examines the convergence characteristics of the “minimized residual method based on the MRTR (three‐term recurrence formula of CG‐type) method” for solving large linear simultaneous equations.

The paper uses an example of magnetic field analysis of permanent magnet type of MRI taking account of the minor loop and eddy current.

It is shown that the preconditioned MRTR method can get a stable and quick convergence for such a relatively ill‐conditioned problem.

Illustrates that the convergence of the Incomplete Cholesky Conjugate Gradient method is one of the important issues in the practical 3D magnetic field analysis.