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Psota B.,FEEC but | Szendiuch I.,FEEC but
Proceedings of the International Spring Seminar on Electronics Technology | Year: 2011

This paper informing about the modeling of BGA structures using ANSYS software. The FEA method is cleared up, but the main emphasis lays on mechanical stress issues. As example is shown the comparison of three different solders and described their usage for electronic components. © 2011 IEEE.

Simek D.,FEEC but
Proceedings of the 2016 17th International Conference on Mechatronics - Mechatronika, ME 2016 | Year: 2016

A thermal model is one of the most important calculations during the designing of an electrical apparatuses. The well designed electrical apparatus must pass through several tests before it is placed to the market. One of these tests is temperature rise test. A paper is focused on the analysis of heating of electrical apparatus. Document contains complete practical calculation of thermal model of disconnector. The main part of work is the temperature rise test of disconnector. In the paper there are also discussed possible causes of deviations between calculated and measured values. © 2016 Czech Technical University in Prague.

Mastny P.,FEEC but | Mastna Z.,FCE but
Proceedings of the 11th International Scientific Conference Electric Power Engineering 2010, EPE 2010 | Year: 2010

Development during few recent years brought about a great interest of the professionals and general public in reviewing the approach in the field of energy use and energy resources. The fossil fuels resources that are integral part of the energy base have been reduced. Reducing these recources is a consequence to present lifestyle of the society which is strongly influenced by high energy consumption. And this trend in consumption has a growing tendency. In the last few years there appears increasing number of discussions on energy sources for low energy buildings. Bivalent and multivalent energy systems have prime importance but experience with its design and operations are little. One factor which influences the development of this issue is the reluktance (and sometimes even ignorance) to install new systems. Regarding these factors there appears a demand to specify the procedures and conditions of the designed combined systems in the building structures with an emphasis on energy economic quality of designed schemes.

Friedl M.,FEEC but | Sedlacek J.,FEEC but
Progress in Electromagnetics Research Symposium | Year: 2010

In the presented contribution are discussed some optimization methods leading to improving of resulting parameters of active filters designated using non-cascade method. Here are discussed and compared real parameters of active filters with modern active elements derived from singly or doubly terminated RLC passive prototype networks. In some examples of designated ARC filters there are prescribed some possibilities and optimization methods which enable to design and optimize of component filter sensitivity.

Fiala P.,FEEC but | Kadlec R.,FEEC but | Drexler P.,FEEC but | Dohnal P.,FEEC but
PIERS 2010 Cambridge - Progress in Electromagnetics Research Symposium, Proceedings | Year: 2010

The paper provides an insight into the issues of integration and application of non-lethal weapons and devices in the field of protection against special-type weapons. The structures like a metamaterials, left-handed type models were analyzed and prepared to the experimental measurements.

Fiala P.,FEEC but | Jirku T.,FEEC but | Drexler P.,FEEC but | Dohnal P.,FEEC but
PIERS 2010 Cambridge - Progress in Electromagnetics Research Symposium, Proceedings | Year: 2010

The aim of this paper is to present the particulars of result research in the HF measurement method and modeling of starting process partial discharge inside of high voltage transformer. The numerical analysis of the electromagnetic wave attenuation helped to set up conditions to decrease it and get of information for sensors conception preparing and detection apparatuses construction and measurement methods.

Korinek R.,Academy of Sciences of the Czech Republic | Bartusek K.,Academy of Sciences of the Czech Republic | Vondrak J.,FEEC BUT
ECS Transactions | Year: 2012

The article deal with NMR measurement and evaluation of relaxation times T1, T2 and diffusion of gel electrolytes based on the NaClO4 inorganic salt during UV polymerization process. Properties and behaviors of gel electrolytes during this process are defined by measured quantities. The measurement is focused on 23Na and 1H nuclei. To measure T1, T2 and diffusion the basic NMR methods were used. The relaxation times of NaClO4 mixed with propylene carbonate (PC) is found to be T1a = 39.2 ms and T1b = 1.5 ms. The approximation, we used two-exponential function and the calculation itself was carried out using a genetic algorithm (GA). ©The Electrochemical Society.

Geschwinder L.,FEEC but | Toman P.,FEEC but
Proceedings of the 11th International Scientific Conference Electric Power Engineering 2010, EPE 2010 | Year: 2010

This paper deals with usage of multivariate statistical analyses methods as tools for simulation reliability of distribution network. At present a description of a feeder failure is created by the help of dependence of a number of failures on length of the feeder, i.e. specific failure rate, which quite mismatch, because even two the same long lines can have different count of failures per annum. Analysis uses at description one's feeder more attributes. Preferred methods for description of feeders groups are a cluster analysis (CLU) and a principal component analysis (PCA). At the end of the paper there is a comparison between performed simulation of SAIFI with negative binomial distribution and values provided by the technique which divides feeders according to their lengths. Then a search for the dependencies between attributes and feeders division is described.

Marcon P.,FEEC BUT | Bartusek K.,FEEC BUT | Bartusek K.,Academy of Sciences of the Czech Republic | Korinek R.,FEEC BUT | And 2 more authors.
2011 34th International Conference on Telecommunications and Signal Processing, TSP 2011 - Proceedings | Year: 2011

The authors describe the techniques for measuring diffusion coefficients and creating DWI and DTI images. In order to increase the accuracy of diffusion coefficient measurement, it is necessary to eliminate the influence of artifacts such as the influence of magnetic field inhomogeneity, eddy currents, or temperature. For these artifact sources, the article presents experimental detection of the magnitude of errors, which is realized using the three measurements method, and proposes correction possibilities. The results are compared with diffusion measurements at different sizes of b-factors. © 2011 IEEE.

Korinek R.,FEEC BUT | Vondrak J.,FEEC BUT | Vondrak J.,Academy of Sciences of the Czech Republic | Bartusek K.,FEEC BUT | And 2 more authors.
ECS Transactions | Year: 2011

In the paper, the properties, particularly relaxation times T1, T2, of gel electrolytes based on the NaClO4 inorganic salt are described. For electrolytes with various concentrations of inorganic salts, relaxation times T1 and T2 were measured at regular intervals during the polymerization, using MR techniques. The reduction of relaxation times during the polymerization, namely T1 from the value 5.5 ms to 1.7 ms and T2 from the value 5.5 ms to 1 ms, indicates a change in the internal structure of the gels and a change in their chemical composition. The waveforms measured will contribute to further studies of gel electrolytes aimed at increasing their electrical conductivity and establishing the influence of water molecules on the conductivity. © The Electrochemical Society.

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