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This paper discusses the lower concentration reinforcement of cathodic ultrafine ceramic particulates, on metal matrices like Zn, Al and alloy‐matrices like Cu Zn, Cu Mn, Al Zn and Ni‐P‐B alloy‐electrodeposits, etc. It is assumed that these ultrafine ceramic particulates in lower concentration‐range are effective in covering the anodic grain‐boundary networks and other anodic‐defect sites, such that there is an effective reduction of surface anodic‐current. It is shown that at a critical threshold particulate concentration, the surface dissolution is minimum, followed by a drastic increase above that concentration. Such increase in dissolution is attributed to the random dispersion of the particulates on the grain‐proper, as these cannot be accommodated within the anodic grain‐boundary channels, micro‐voids and other defect sites. As such they form stress‐raiser points and enhance surface dissolution. This paper also discusses the correlation of the grain boundary structures, particulate trapping capacity of the matrix and the galvanic stress factors due to random distribution of particulates.

The purpose of this study was to design, fabricate and test devices based on transformers integrated with low-temperature co-fired ceramic (LTCC) modules with isolation between primary and secondary windings at the level between 6 and 12 kV.

Insulating properties of the LTCC were examined. Dielectric strength and volume resistivity were determined for common LTCC tapes: 951 (DuPont), 41020, 41060 (ESL), A6M (Ferro) and SK47 (KEKO). According to the determined properties, three different devices were designed, fabricated and tested: a compact DC/DC converter, a galvanic separator for serial digital bus and a transformer for high-voltage generator.

Breakdown field intensity higher than 40 kV/mm was obtained for the test samples set, whereas the best breakdown field intensity of about 90 kV/mm was obtained for 951 tape. The materials 41020 and 951 exhibited the highest volume resistivity. Fabricated devices exhibited safe operation up to a potential difference of 10 kV, limited by minimum clearance. Long-term stability was assured by over 20 kV strength of inner dielectric.

This paper contains description of three devices made in the LTCC technology for application in systems with high-voltage isolation requirement, for example, for power or railway power networks.

The results show that LTCC is a suitable material for fabrication of high-voltage devices with integrated passives. Technology and properties of three examples of such devices are described, demonstrating the ability of the LTCC technology for application in reliable high-voltage devices and systems.

The rapid advances in recent years made within the field of fibre optics and opto‐electronics open up new opportunities within many areas.

This paper aims to present a new non‐destructive method of brick wall dampness testing in real building structures. The electrical impedance tomography (EIT) method makes it possible to obtain a distribution of wall dampness. The paper aims to give basic information about the measuring system, including prototype equipment. The setup was used to determine the dampness of test brick walls on a specially built laboratory test rig. The paper seeks to compare test results obtained by the non‐destructive impedance tomography method with the results obtained by the conventional destructive dry‐weight method.

The paper adopts a tomography approach to control humidity inside of the brick walls. In case of brick walls other nondestructive methods fields, for example, the ultrasonic tomography is useless. On the other hand the most popular dry‐weight method is strictly forbidden for historical buildings. As a forward solver, functionally graded material boundary element method was used.

The paper proves that diffuse tomography could provide reliable results with respect of humidity content inside the brick walls. This method could provide 3D humidity distribution inside of the brick walls.

It is expected that the technique's impact will be limited to site inspection of building following floods or to evaluate older damp buildings.

The presented technique can eventually lead to much simpler, cheaper and more efficient evaluation of the moisture content in walls. This can revolutionize some procedures in civil engineering.

The application has commercial potential and could result in more cost‐effective repair of old buildings, which has an economic impact on society.

The authors propose application of the diffuse tomography for nondestructive investigation of brick walls. According to the authors' best knowledge this is a novel approach.

This paper aims to describe a new concept of transformer based on the displacement current. The paper shows how this idea can be translated into reality and presents an example of a working design.

The authors replace the primary winding of the transformer with a capacitor. The displacement current between the capacitor plates induces a magnetic flux in the core. This flux in turn induces electromotive force in the classical secondary winding.

The basic mathematical aspects illustrated by results obtained from a simulation developed using a commercial software ANSYS-HFSS are given. The saturation of the magnetic core due to the applied high-frequency range is investigated and simulated using a finite difference time domain code implemented in MATLAB. A prototype transformer was built and tested; the obtained results confirm the previous ones from simulations.

A new concept of the single winding transformer was used as a pulse forming circuit.

Analytical determination of harmonic components of current in electric circuits containing semiconductor converters with the use of a small parameter method (SPM) in frequency domain. The paper aims to discuss these issues.

A SPM realized in frequency domain was used in the analytical analysis of electric circuits with semiconductor converters. An automated method of formation of orthogonal harmonic components of electrical values on the basis of discrete convolution algorithm was used to provide the possibility of realization of calculation in frequency domain. A nonlinear characteristic of a semiconductor converter was presented by the method of numerical approximation. A numerical structured simulation method was applied to determination of the reference values of current in the analyzed circuit. Laws of theoretical electrical engineering were used for formation of the equations of voltage balance in the circuit with a nonlinear element.

It is shown that application of a SPM with its realization in frequency domain enables significant simplification of the process of the analysis of electric circuits with semiconductor converters in an analytical form and facilitation of calculation automation. Analytical and numerical calculation of a circuit with a diode under active-inductive load demonstrated efficiency and sufficient accuracy of the proposed method. It is shown that increase of the order of approximating polynomial and of the number of the analyzed harmonics provides the improvement of the accuracy of numerical calculations.

The results of the work can be used in calculation of electrotechnical devices containing semiconductor appliances and electric devices with nonlinear characteristics. Moreover, the obtained results enable studying the processes of compensation of current higher harmonics in electric networks with a nonlinear load containing semiconductor converters.

For the first time it was proposed to apply a SPM with its realization in frequency domain to the analysis of nonlinear electric circuits. The significance of the paper consists in the fact that the offered method makes it possible to carry out both circuit analytical and numerical analysis with the possibility of its automation.

Concrete forms a major component of the national infrastructure. Corrosion of reinforced steels embedded in concrete has recently received wide attention in R&D programmes. Different cases have been reported showing failures of concrete structures which means huge loss. An attempt has been made to identify the different factors affecting the corrosion of embedded steel. Comparative evaluation of different protective schemes use of additives in concrete admixtures and the application of the cathodic protection technique has been discussed.

Three types of alloys have been chosen, and subjected to three different varieties of macro‐strains, e.g. corrosion‐pittings in a high strength low‐alloy, sensitization‐induced precipitation in an unstabilized 304 s.s. and cold‐working stresses in FeNiMoB and FeNiMoBSi metallic glass foils for diagnostic studies in corrosion console. Attempts to correlate the galvanic activity of these substrates with the imposed galvanic micro‐strains using an entirely new type of criterion, namely the distance between the forward and backward‐scan, indicated by “d” value in terms of current at a particular chosen potential. This technique, however, is limited by a threshold extent of surface‐strains, in terms of either anodic or cathodic stress concentration‐points above which the surface either develops an anodically activated film or it starts behaving as an effective cathode. The galvanic interactions of the surface, under such conditions, become minimal so that the “d” values no longer remain an increasing function of the increasing surface galvanic strain.

The purpose of this study is to study the pitting caused by Ca-Al-O-S composite inclusions of low-alloy steel in 3 Wt.% NaCl solution and 0.01M NaHSO3 solution.

The corrosion in 0.01M NaHSO3 was much weaker than in 3 Wt.% NaCl 3D display of the pitting formation and development process that has been calculated using scanning electron microscope (SEM) and laser scanning confocal microscopy (LSCM). In addition, a corrosion mechanism of pitting formation by galvanic interaction of composite inclusion and base metal has been proposed.

Results show that in immersion test, metal base around inclusions was dissolved due to corrosion. Corrosion on the metal base closer to inclusions was more severe.

A corrosion mechanism of pitting formation by galvanic interaction of composite inclusion and base metal has been proposed.

The paper aims to present a learning environment for optimal synthesis of voltage regulator circuits (LEOS‐VRC) using PSPICE simulator.

LEOS‐VRC supports a database with voltage regulator circuits edited as projects in PSPICE compatible format and a methodology for optimal synthesis. The methodology is based on the estimation of multiple voltage regulator circuits' realizations over a given specification, through comparative study in PSPICE, using a set of predefined specific electrical characteristics, which values are determined from simulation waveforms. LEOS‐VRC allows integrating the voltage regulator circuit in a power supply system through adding transformer, rectifier and control stages. Both linear and switch‐mode power supplies are considered.

The methodology and examples proposed illustrate the efficiency of LEOS‐VRC for teaching and self‐education in the area of power supply circuit design.

In future LEOS‐VRC database will be enlarged with new voltage regulator circuit topologies and new controller circuits.

LEOS‐VRC is suitable for students in electronics and designers of power supply circuits.

With LEOS‐VRC students become familiar with multisolution synthesis. By analyzing the complex behaviour of the power supply system and applying comparative study and optimization criteria, they can make a motivated selection of an optimal voltage regulator design solution for a concrete application.