Wyniki wyszukiwania - Biblioteka Nauki

1

The influence of the surface load exerted by a piezoelectric contact sensor on testing results: II. The electrical transients generated by piezoelectric sensor

100%

Radziszewski L.

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tom Vol. 28, no. 2

93-100

EN

The influence of a strong discontinuity wave on its measurement with a apiezoelectric sensor was analysed analytically. The one-dimensional model of the mechanical contact between the ultrasonic sensor and the solid medium was developed. Part I of the paper contained the discussion of the displacement field in the solid, the analysis of electrical transients generated by piezoelectric tranducer are given in this paper. The evaluation was made locally at the front of distortion. It was found that the relative error of PZT transducer's indication ranges from 26% up to 70%. After a long period of time (depending on the mass M) the influence of surface loading becomes much smaller.

2

The influence of the surface load exerted by a piezoelectric contact sensor on testing results: I. The displacement field in the solid

100%

Radziszewski L.

|

tom Vol. 28, no. 2

71-91

EN

The influence of a strong discontinuity wave on its measurement with a piezoelectric sensor was analysed analytically. The one-dimensional model of the mechanical contact between the ultrasonic sensor and the solid medium was developed. The displacement field was calculated with the d'Alambert's method. The evaluation was made locally at the front of the distortion. It was found that the relative difference of a displacements between the free and loaded surfaces ranges from 10% to 72% and the mass M has no influence on it in the first time interval. It is affected not only by the wave impedances but also by surfaces of the sensor and sample. After a long period of time (depending on the mass M) the influence of the surface loading becomes much smaller. Part I of the paper contains the discussion of the displacement field in the solid, the electricaltransients generated by the piezoelectic sensor are given in Part II.

3

Laser Generated Ultrasonic Waves in Polymer Composites

100%

Radziszewski L.

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1999

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tom Vol. 20

203-216

4

Propagation parameters of ultrasonic waves generated by laser in plastics

100%

Radziszewski L.

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tom Vol. 19

231-238

5

Cepstral analysis of vowels of esophageal speakers

63%

Mięsikowska M. , Radziszewski L.

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tom R. 58, nr 11

968-971

EN

The aim of this study was to compare normal (NL) and esophageal (ES) speech signals in scope of vowels in order to show differences between signals. A discriminant analysis based on cepstral features extracted from vowels of NL and ES speech was performed. The comparison was made on the basis of the classification function coefficients and the results of the classification for each speech. Vowels recordings were acquired from 10 NL speakers and 10 ES speakers. The discriminant analysis was based on cepstral features extracted from vowel recordings, and was performed separately for NL speech and ES speech. Then a comparison between coefficients of classification functions of NL and ES vowels using the Euclidean distance was made. Based on the resulting classification matrix of NL and ES speech, the results of classification were compared. The discriminant analysis based on cepstral features showed 76% of the mean classification score for ES speech and 90% for NL speech. The Euclidean distance showed low differences between the vowel /a/ of NL speech and the vowel /a/ of ES speech and between the vowel /e/ of NL speech and the vowel /e/ of ES speech.

PL

Celem pracy było porównanie sygnału mowy normalnej (NL) i przełykowej (ES) w zakresie samogłosek w celu wykazania różnic pomiędzy sygnałami. Przeprowadzono analizę dyskryminacyjną współczynników cepstralnych uzyskanych z samogłosek mowy NL i ES. Porównania dokonano na podstawie uzyskanych współczynników funkcji klasyfikacyjnych oraz otrzymanych wyników klasyfikacji dla każdej mowy. Sygnał mowy każdej samogłoski pozyskany został od 10 mówców mowy NL i 10 mówców mowy ES. Analizę dyskryminacyjną przeprowadzono w oparciu o współczynniki cepstralne oddzielnie dla mowy NL i mowy ES. Następnie dokonano porównania uzyskanych współczynników funkcji klasyfikacyjnych samogłosek mowy NL i mowy ES, wykorzystując do tego celu odległość Euklidesa. Na podstawie macierzy klasyfikacji otrzymanej dla mowy NL i ES porównano rezultaty klasyfikacji. Analiza dyskryminacyjna w oparciu o współczynniki cepstralne wykazała 76% jako średni wynik klasyfikacji dla mowy ES, natomiast 90% dla mowy NL. Odległość Euklidesa wskazuje na najmniejsze różnice w zakresie samogłoski /a/ i /e/ mowy NL i ES.

6

Determining selected diesel engine combustion descriptors based on the analysis of the coefficient of variation of in-chamber pressure

63%

Bąkowski A. , Radziszewski L.

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tom Vol. 63, nr 2

457--464

EN

This paper presents a method that uses the coefficient of variation (COV) of pressure in a diesel engine combustion chamber to determine the crank angle degree (CAD) for which the heat release rate (HRR) reaches the maximum value. The COV was proposed for determining the point corresponding to the angle of start of combustion (SoC). Regression models were fit with these descriptors for the engine powered by diesel, biodiesel or a combination of both, operating under full- or part- load conditions. The uncertainty parameter in these models was determined. Good agreement between the experimental results and the literature data shows the validity of the analysis.

7

Automatic recognition of voice commands in car

63%

Mięsikowska M. , Radziszewski L.

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tom Vol. 25

285--288

EN

The aim of this study was to evaluate the recognition process of driver’s voice commands spoken in car cabin using Sphinx-4 – the speech recognizer written entirely in Java language. Sphinx-4 recognizer was tested in real-time conditions in standalone car with engine on/off. The speech material consisted of sentences spoken directly to the microphone. Results showed significant differences in recognition accuracy obtained in different conditions (engine on/off).

8

The general formula for calculation of fundamental frequency of axisymmetric vibrations of circular plates with linearly variable thickness

63%

Jaroszewicz J. , Radziszewski L.

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tom nr 19(4)

401--410

EN

This work has derived the general formula, sufficiently precise for engineering calculations of base frequency of axisymmetric free vibrations of uniform, circular diaphragm type plates clamped at the edge with linearly variable thickness. To solve the boundary problem, the Cauchy’s function method and characteristic series have been applied. The above formula has been derived on the basis of Dunkerley’s formula which is based on the first major term of the characteristic series and results in the simplest, lower bound estimator. The analysis of the formula shows that the base frequency coefficient for diaphragm plates clamped at the edge depends to only a small extent on the Poisson’s ratio, and therefore it may be averaged in the case of construction materials. Comparison of the calculations results of the simplest lower bound estimators for the base frequency obtained by using proposed method, with the results known from the literature as precise solutions, including Conway method, confirmed the high accuracy of the proposed method.

9

Modeling of cylinder pressure in compression ignition engine with use of genetic-fuzzy system. Part 2: Engine fueled by FAME

51%

Kekez M. , Ambrozik A. , Radziszewski L.

Diagnostyka

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2008

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tom nr 4(48)

13-16

EN

This paper concerns measurement and modeling cylinder pressure in diesel engine. The main aim of this paper is to build the analytical-empirical model of work of engine fueled by different fuels. The experiments on engine test bench were conducted and a model of engine work was created by means of proposed GFSm system. In Part 1 the engine was fueled by diesel oil, and in Part 2 - fueled by methyl esters of rapeseed oil (FAME).

PL

Praca dotyczy zagadnień związanych z pomiarem i modelowaniem przebiegów ciśnień w cylindrze silnika o zapłonie samoczynnym. Głównym jej celem jest budowa modelu analityczno-eksperymentalnego pracy silnika zasilanego różnymi paliwami. Przeprowadzono badania na hamowni i opracowano model pracy silnika za pomocą proponowanego systemu GFSm. W części pierwszej pracy silnik zasilany był olejem napędowym, a w części drugiej - estrami metylowymi oleju rzepakowego (FAME).

10

Modeling of cylinder pressure in compression ignition engine with use of genetic-fuzzy system. Part 1: Engine fueled by diesel oil

51%

Kekez M. , Ambrozik A. , Radziszewski L.

Diagnostyka

|

2008

|

tom nr 4(48)

9-12

EN

This paper concerns measurement and modeling cylinder pressure in diesel engines. The aim of this paper is to build the empirical-analytical model of engine work. The experiments on engine test bench were conducted. The new genetic-fuzzy system GFSm was proposed. By means of GFSm, the engine model was built. This model allows simulation of cylinder pressure, for each allowable crankshaft speed. The model can be used to evaluate the quality of working cycles of piston engine with accuracy required in practical technical applications.

PL

Praca dotyczy pomiaru i modelowania przebiegów ciśnień w cylindrze silnika o zapłonie samoczynnym. Celem pracy jest budowa analityczno-empirycznego modelu pracy silnika. Przeprowadzono badania eksperymentalne na hamowni oraz opracowano nowy system genetyczno-rozmyty GFSm. Przy jego użyciu zbudowano model pracy silnika, który pozwala przeprowadzać symulację przebiegów ciśnień w cylindrze silnika, dla wszystkich dopuszczalnych prędkości obrotowych wału korbowego. Może także służyć do oceny jakości cykli pracy tłokowych silników spalinowych z dokładnością wymaganą w praktycznych zastosowaniach technicznych.

11

Modeling of cylinder pressure in compression ignition engine with use of genetic-fuzzy system

51%

Ambrozik A. , Kekez M. , Radziszewski L.

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2008

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tom Z. 10, Vol. 2

419-430

EN

This paper concerns measurement and modeling cylinder pressure in diesel engines. The aim of this paper is to build the empirical-analytical model of engine work. The experiments on engine test bench were conducted. The new genetic-fuzzy system GFSm was proposed. By means of GFSm, the engine model was built. This model allows simulation of cylinder pressure, for each allowable crankshaft speed. The model can be used to evaluate the quality of working cycles of piston engine with accuracy required in practical technical applications.

PL

Praca dotyczy pomiaru i modelowania przebiegów ciśnień w cylindrze silnika o zapłonie samoczynnym. Celem pracy jest budowa analityczno-empirycznego modelu pracy silnika. Przeprowadzono badania eksperymentalne na hamowni oraz opracowano nowy system genetyczno-rozmyty GFSm. Przy jego użyciu zbudowano model pracy silnika, który pozwala przeprowadzać symulację przebiegów ciśnień w cylindrze silnika, dla wszystkich dopuszczalnych prędkości obrotowych wału korbowego. Może także służyć do oceny jakości cykli pracy tłokowych silników spalinowych z dokładnością wymaganą w praktycznych zastosowaniach technicznych.

12

Vibroacoustic Real Time Fuel Classification in Diesel Engine

51%

Bąkowski A. , Kekez M. , Radziszewski L. , Sapietova A.

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tom Vol. 43, No. 3

385--395

EN

Five models and methodology are discussed in this paper for constructing classifiers capable of recognizing in real time the type of fuel injected into a diesel engine cylinder to accuracy acceptable in practical technical applications. Experimental research was carried out on the dynamic engine test facility. The signal of in-cylinder and in-injection line pressure in an internal combustion engine powered by mineral fuel, biodiesel or blends of these two fuel types was evaluated using the vibro-acoustic method. Computational intelligence methods such as classification trees, particle swarm optimization and random forest were applied.

13

The effect of influence of conservative and tangential axial forces on transverse vibrations of tapered vertical columns

51%

Jaroszewicz J. , Radziszewski L. , Dragun Ł.

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tom nr 20(4)

333--342

EN

The Cauchy function and characteristic series were applied to solve the boundary value problem of free transverse vibrations of vertically mounted, elastically supported tapered cantilever columns. The columns can be subjected to universal axial point loads which considerate – conservative and follower /tangential/ forces, and to distributed loads along the cantilever length. The general form of characteristic equation was obtained taking into account the shape of tapered cantilever for attached and elastically secured. Bernstein-Kieropian double and higher estimators of natural frequency and critical loads were calculated based on the first few coefficients of the characteristic series. Good agreement was obtained between the calculated natural frequency and the exact values available in the literature.

14

Selected operating problems of central pumps

51%

Dragun Ł. , Jaroszewicz J. , Radziszewski L. , Antoniuk V.

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2018

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tom Vol. 115, iss. 12

159--165

EN

The article presents problems of maintaining the Z-type supply pumps and network operated in ENEA Wytwarzanie Sp. z o.o. Heat Segment, Białystok Branch with the use of thermovision and vibrodiagnostic studies. The practical aim is to select parameters of the supply pumps (multistage) which ensure energy efficient operation despite a serious operational wear - a 20-year working period. Commissioning of a Z-type feed pump and thermovision tests of selected machine construction elements constituted the subject of the research.

PL

W artykule przedstawiono problematykę utrzymania ruchu pomp zasilających typu Z i sieciowych eksploatowanych w ENEA Wytwarzanie Sp. z o.o. Segment Ciepło, Oddział Białystok z wykorzystaniem badań termowizyjnych oraz wibrodiagnostycznych. Celem praktycznym jest dobór parametrów pomp zasilających (wielostopniowych), zapewniających energooszczędną eksploatację mimo poważnego zużycia eksploatacyjnego – 20 letni okres pracy. Przedmiotem badań był rozruch pompy zasilającej typu Z oraz badania termowizyjne wybranych elementów konstrukcyjnych maszyny.