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Czestochowa, Poland

Częstochowa University of Technology is the largest and oldest institution of higher education in Częstochowa, Poland. All faculties of the University have the right to grant doctoral degrees , and three of them also offer PhD habilitation. Wikipedia.

Kijo-Kleczkowska A.,Czestochowa University of Technology

Combustion technologies using coal-water suspensions create a number of new possibilities for organising combustion processes so that they fulfil contemporary requirements (e.g., in terms of the environment protection-related issues). Therefore, an in-depth analysis is necessary for examining the technical applications of coal in the form of a suspension as a fuel. The paper undertakes the complex study of coal-water suspension combustion in air and in the fluidised beds. This, according to the author, best simulates the conditions that should be satisfied in order to use the new "fuel" efficiently and ecologically. An important element of the study was the identification of coal-water suspension drops, its complex morphology and evolution in the combustion process. The mathematical model enables the prognosis for change of the surface and the centre temperatures and a mass loss of the coal-water suspension during combustion in air and in the fluidised bed. © 2010 Elsevier Ltd. All rights reserved. Source

Marek M.,Czestochowa University of Technology
Physica D: Nonlinear Phenomena

Growth processes simulated on a regular cellular automaton grid with simple capture rules are considerably influenced by the structure of the grid. Some of the growth directions are favored over others leading to highly anisotropic or, at least, orientation-dependent growth pattern. A new method is proposed for significant reduction of artificial grid anisotropy in 2D and 3D cellular automata with continuous state variable. The method employs additional diffusion process controlling the growth rate and allows for isotropic or anisotropic growth where the anisotropy is decoupled from the grid structure. Verification of the method is provided in the case of isotropic circular growth, isotropic growth of various shapes in uniform and spatially varying fields, and anisotropic growth with respect to orientation and symmetry of the pattern. Finally, the reduction of grid anisotropy is demonstrated in 2D simulation of dendritic grain growth in pure metal. The shape of the grain is shown to be virtually independent of the orientation. An example growth of a grain with six-fold symmetry is also included. © 2013 Elsevier B.V. All rights reserved. Source

Werner K.,Czestochowa University of Technology
International Journal of Fatigue

In the paper, the results of crack tip opening displacement (CTOD) and crack opening displacement (COD) in place of crack initiation as well as the fatigue crack growth rate in higher strength steel are presented. The investigation were carried out on flat specimens with central notch under constant amplitude tensile fatigue loading at stress ratio R = 0.2 and different value of the stress σ max. The test results showed that with growth of crack length l grew values of the CTOD and COD. In the work, it was proposed calculation of the CTOD value on basis various dependence of plastic zone radius on crack tip. © 2011 Elsevier Ltd. All rights reserved. Source

An approach for solving the unit commitment problem based on genetic algorithm with binary representation of the unit start-up and shut-down times is presented. The proposed definition of the decision variables and their binary representation reduce the solution space and computational time in comparison to the classical genetic algorithm approach to unit commitment. The method incorporates time-dependent start-up costs, demand and reserve constraints, minimum up and down time constraints and units power generation limits. Penalty functions are applied to the infeasible solutions. Test results showed an improvement in effectiveness and computational time compared to results obtained from genetic algorithm with standard binary representation of the unit states and other methods. © 2013 Elsevier Ltd. All rights reserved. Source

Dudek G.,Czestochowa University of Technology
IEEE Transactions on Evolutionary Computation

A new multiclass classifier based on immune system principles is proposed. The unique feature of this classifier is the embedded property of local feature selection. This method of feature selection was inspired by the binding of an antibody to an antigen, which occurs between amino acid residues forming an epitope and a paratope. Only certain selected residues (so-called energetic residues) take part in the binding. Antibody receptors are formed during the clonal selection process. Antibodies binding (recognizing) with most antigens (instances) create an immune memory set. This set can be reduced during an optional apoptosis process. Local feature selection and apoptosis result in data-reduction capabilities. The amount of data required for classification was reduced by up to 99%. The classifier has only two user-settable parameters controlling the global-local properties of the feature space searching. The performance of the classifier was tested on several benchmark problems. The comparative tests were performed using k-NN, support vector machines, and random forest classifiers. The obtained results indicate good performance of the proposed classifier in comparison with both other immune inspired classifiers and other classifiers in general. © 2012 IEEE. Source

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