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Pajak M.,Radom University of Technology
Journal of Intelligent and Fuzzy Systems

Quality of power units' maintenance schedule is one of the most important factors, which influences reliability and efficiency of power plant exploitation process. The schedule is created during a planning process taking into consideration a lot of different criteria. These criteria result from bidirectional connections between power plant exploitation system and surrounding systems. Therefore they are formulated in completely different domains. The criteria often are defined approximately. Frequently they are contradictory so it is not possible to fulfil all the criteria simultaneously. Because of all these difficulties, the creation process of coherent assessment system, comprising all considered criteria, is very complicated. Additionally, the number of maintenance schedule possible variants is very big. Therefore, to reach high quality of maintenance management, it is necessary to apply automatic system of power units maintenance schedules generation. This paper describes the implementation of artificial intelligence techniques in the area of maintenance management. The automatic system of power units maintenance schedules generation was created using genetic algorithms as optimization technique and developed fuzzy assessment system. In the paper, the industrial implementation of the system is also presented. © 2015 - IOS Press and the authors. Source

Brociek W.,Warsaw University of Technology | Wilanowicz R.,Radom University of Technology
Przeglad Elektrotechniczny

The paper presents a circuit model of three phase arc arrangement, taking into account the nonlinearity of the arc appearing In the particular phases as well as the windings vector groups of a furnace transformer. This model was designed on the ground of parameters, resulting from a voltage current characteristic of the arc. At modeling of changes of parameters of an arc we applied the random values of resistance. The values of higher harmonics of current and voltage for each considered case have been evaluated by using the simulation program MicroCap - 8. In the paper we have included the exemplary results of numerical calculations. Source

Religa P.,Radom University of Technology | Kowalik-Klimczak A.,Warsaw University of Technology | Gierycz P.,Warsaw University of Technology | Gierycz P.,Polish Academy of Sciences

Results of studies of the effects of concentrate salt solutions characterized by low pH, on the nanofiltration membrane surface properties used for the separation of chromium(III) have been presented in this paper. It was shown that the low pH of the concentrate salt solutions and cleaning bath with hydrochloric acid irreversibly altered the charge of tested membranes. As the consequence an instability of permeability and selectivity of the membrane during the process was noticed. The effect of alkaline bath used after cleaning with a solution of hydrochloric acid to regenerate the surface charge of tested membranes was also examined. The results showed that the use of bath in the form of sodium hydroxide leads to the partial recovery of a low surface charge of the membranes. In addition a significant improvement in the stability of the tested NF membranes used for the separation of chromium(III) from concentrate salt solutions at low pH was observed. Moreover, SEM images obtained for the tested membranes cleaned with solutions of HCl and NaOH indicated no mechanical defects in the structure of the examined membranes. © 2012 Elsevier B.V. Source

Komorska I.,Radom University of Technology
Solid State Phenomena

The method of modelling the signal of vibrations of the internal combustion engine based on the discrete wavelet transform (DWT.) is presented in the paper. This method is suitable for the representation of transient processes, which occurs in the vibroacoustic signal (VA) generated by the engine. The model is identified on the basis of the vibration signal recorded when the car is driving at a constant speed. The base model and its measures are created for the new engine and the control measurements, performed either at the determined time periods or car mileage, are compared to them. This base model must be actualised after each engine overhaul and as its wear and tear progresses, due to changes of the vibration characteristics. On account of a random character of vibration responses the envelope of the modelled signal is utilised for diagnostic purposes. The model based diagnostic method was verified in the paper on the example of the engine exhaust valve defect. © (2012) Trans Tech Publications. Source

Bojarczak P.,Radom University of Technology
Insight: Non-Destructive Testing and Condition Monitoring

Squat flaws, when left unsupervised, can pose a threat to the safety of railway traffic. Unfortunately, as surface flaws, they cannot be detected by traditional ultrasonic methods. The application of eddy current to their detection is extremely difficult in the conditions occurring on the railway track. It seems that vision-based techniques can be a good alternative solution. The paper presents an algorithm allowing for the detection of these flaws. It uses wavelet transform to extract the rail from the background of the image. A Gabor filter bank along with a support vector machine (SVM) as a classifier were used in the squat detection process. The optimal number of features used to discriminate between the squat and the area without squat was selected with the help of the sequential feature selection method. The overall classification rate for the system was 93%. Source

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