Wyniki wyszukiwania - Biblioteka Nauki

1

Evaluation of nonlinear constants from results of acoustic measurements. Regularization of problem

100%

Leble S. B. , Vereshchagin D. A. , Vereshchagina I. S.

Hydroacoustics

|

2003

|

tom Vol. 6

159--166

EN

The method of nonlinear constants B/A and C/A determination is discussed. It bases on comparison of experimental results of acoustic signal propagation with results of theoretical investigation of this problem. It is shown, that this problem, in general case, is ill-posed. So we use methods of ill-posed problem solution regularization. The values of the constants, which were extracted using this method, are in good accordance with estimations by other authors.

2

Assessment Effects of Humidification of Guitars by Complexity Measures of the Sound Level During Sustain

80%

Stępień R. , Wrzeciono P.

Archives of Acoustics

|

2024

|

tom Vol. 49, nr 2

189--197

EN

Air humidity significantly affects the sound of wooden instruments. The sound quality decreases when the instrument is exposed to low humidity for an extended period. Therefore, the instrument is treated with a humidifier to improve sound quality. This study aimed to verify the effectiveness of the humidification process by analyzing the quality of guitar sound with the methods used in signal complexity studies, such as Higuchi’s fractal dimension (HFD), symbolic analysis, and empirical mode decomposition (EMD). The sound quality was determined by the sound levels measured before, during, and after the guitars’ humidification. The methods used consistently confirmed the improvement of the guitar sound quality after the humidification process. Moreover, it was concluded that the sound quality changes irregularly during the humidification process.

3

Statistical Analysis of the Equivalent Noise Level

80%

Batko W. , Przysucha B.

|

2014

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tom Vol. 39, No. 2

195--198

EN

The authors focus their attention on the analysis of the probability density function of the equivalent noise level, in the context of a determination of the uncertainty of the obtained results in regard to the control of environmental acoustic hazards. In so doing, they discuss problems of correctness in the applicability of the classical normal distribution for the estimation of the expected interval value of the equivalent sound level. The authors also provide a set of procedures with respect to its derivation, based upon an assumption of the determined distribution of the measurement results. The obtained results then create the plane for the correct uncertainty calculation of the results of the determined controlled environmental acoustic hazard coefficient.

4

The Acoustics of the Catacombs

80%

Iannace G. , Trematerra A. , Qandil A.

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tom Vol. 39, No. 4

583--590

EN

The catacombs are underground places. This paper reports the results of acoustic measurements carried out inside the catacombs of “San Gennaro” (Naples) and in those one of “San Callisto” (Rome). Originally the catacombs were also used to perform sacred functions, although we don’t know the type of these functions i.e. if they were spoken, sung or performed as psalms. This paper presents acoustic measurements carried out in catacombs using the impulse response method, and by the analysis of the monaural acoustic parameters, (T30, EDT, C80, D50 and STI), the authors intend to understand the type of religious ceremony performed in the catacombs. If the catacombs had been reverberant places, they could not have been used for prayers because the echoes would have created difficulties in concentration and meditation for the devotees due to the poor speech comprehension.

5

Acoustic research on Baltic fish behaviour in relation to variable environmental factors

80%

Orłowski A.

Oceanological Studies

|

2000

|

tom Vol. 29, No. 2

19-32

EN

The paper describes new methods and approaches to treating acoustic, biological and environmental data collected during surveys. Examples of their applications are given. The aim of all the methods presented is to correlate acoustic, biological and environmental data with the task of estimating and mathematically describing (modelling) interactions between environment, fish, and its relevant acoustic response. The methods are intended for marine ecologists and fisheries acous-ticians.

6

Estimation of Acoustic Impedance for Surfaces Delimiting the Volume of an Enclosed Space

80%

Piechowicz J. , Czajka I.

Archives of Acoustics

|

2012

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tom Vol. 37, No. 1

97-102

EN

Several methods can be applied for analyses of the acoustic field in enclosed rooms namely: wave propagation, geometrical or statistical analysis. The paper presents problems related to application of the boundary elements method to modelling of acoustic field parameters. Experimental and numerical studies have been combined for evaluation of acoustic impedance of the material used for the walls of a model room. The experimental studies have been carried out by implementing a multichannel measuring system inside the constructed model of an industrial room. The measuring system allowed simultaneous measurements of the source parameters – the loudspeaker membrane vibration speed, the acoustic pressure values in reception points located inside the model space as well as phase shifts between signals registered in various reception points. The numerical modelling making use of the acoustic pressure values measured inside the analyzed space allowed determination of requested parameters of the surface at the space boundary.

7

Numerical Compensation of Air Absorption of Sound in Scale Model Measurements

80%

Ćirić D. G. , Pantić A.

Archives of Acoustics

|

2012

|

tom Vol. 37, No. 2

219-225

EN

The absorption of sound in air represents one of the main problems of the scale model measurements. This absorption, especially at higher frequencies, is considerably greater than the value determined by the law of acoustical similarity between the full scale and the scale model. Different alternatives are applied for compensation of the excess air absorption including a numerical compensation. In this paper, a modified approach to numerical compensation is proposed. It is based on compensation of the sound decay only, and not background noise. As a consequence, there is no an increase of background noise in the compensated impulse response. The results obtained by the proposed procedure are compared to the corresponding ones obtained by the other procedures.

8

A method of determining the low concentration gaseous mixtures be means of acoustic measurements

80%

Urbańczyk M.

Journal of Technical Physics

|

1998

|

tom Vol. 39, no 2

199-203

EN

The paper deals with a method of determining the composition of a mixture of gases, measuring the differential frequency of the matrix of acoustic oscillators of the SAW type.

9

A concept of an actuator for the positioning measurement system in an anechoic room

80%

Batko W. , Felis J. , Flach A. , Kamisiński T. , Giesko T. , Zbrowski A.

Archives of Acoustics

|

2008

|

tom Vol. 33, No. 2

201-207

EN

Automation of acoustic measurements constitutes a considerable challenge to designers. On one hand, the special character of acoustic measurements in an anechoic room requires designs that minimize disturbances to the acoustic field; on the other hand, automation always involves the introduction of additional mechanical elements, which disturb this field. The authors of this paper attempt to reconcile these conflicting demands by designing a mechatronic measurement system. On the basis of known solutions and current measurement needs, a number of concepts has been proposed, and a design has been identified that can be implemented in the room under study.

10

Harmonical and modal analysis to determine the anisotropic properties of aviation composite materials

70%

Acopyan A. , Axenov V. , Shevtsov V. , Soloviev A. , Tamarkina E.

Journal of KONES

|

2007

|

tom Vol. 14, No. 3

11-18

EN

The value of all composite elastic modules has the crucial influence on dynamic behaviour of aviation load-bearing structures. Numerous experimental techniques and standards are used to characterize the elastic properties of polymeric composite materials. Among this is the large group of static tests, acoustic methods based on longitudinal, lateral or shear surface sound wave speed measurements and also on vibrating surfaces amplitude measurements. However, preparation specimens for static test with shape required by standards not always possible from already manufactured piece. Again the designated dynamic experiment introduces difficulties of investigated specimen acoustic isolating, impossibility of some required wave type excitation and performing of displacements field measurement with guaranteed precision. In this study an acoustic method is developed using the measure of all specimen's eigenfrequencies in a certain frequency range. Small rectangular composite specimen is excited by glued piezoelectric actuator and response is measured by piezoelectric sensor. Preliminary performed finite-element (FE) analyses serve to think the vibration natural modes of linked mechanical system - specimen and piezoelectric element. In this FE analyse the rough estimations of all elastic constants obtained from other independents (as a rule static) experiments were used. Further the amelioration of initial elastic modules was performed. Thereby the target nonlinear functional dependent on all quest modules was minimized by genetic and (or) Levenberg-Marquardt algorithm.

11

Możliwości uproszczenia procedury monitorowania hałasu tramwajowego z punktu widzenia automatyzacji procesu analitycznego

60%

Komorski P. , Czechyra B. , Nowakowski T.

|

tom Z. 170

25--30

PL

W artykule przedstawiono analizę pomiarów sygnałów akustycznych generowanych podczas testu pass-by wybranego typu lekkich pojazdów szynowych w warunkach normalnej eksploatacji. Pomiary hałasu wykonano zgodnie z wymaganiami normy ISO 3095. Celem analizy było sprawdzenie, w jakim stopniu uwzględnianie czasu przed i po przejeździe pojazdu przez punkt pomiarowy, ma wpływ na obliczanie ekspozycyjnego poziomu dźwięku A.

EN

The article presents the results of analysis carried out for automatization of analytical procedures for tram noise monitoring. The primary analytical procedures were developed based on the ISO 3095:2005 standard. However, it was decided to develop own research methodology. Due to, that fulfillment of all the requirements in strict urban area is impossible. The analysis of sensitivity symptom to different averaging data condition changes is presented in the comparative study. Also the possibility of its application in the vibroacoustic monitoring system of trams is proposed. There are the two main aims of the study. Firstly, checking the extent to which, the time before and after the passage of the vehicle through the measurement point, has an impact on the calculation of the exposure sound level A (SEL), on selected tram. Secondly, ensure if obtained characteristics can be considered as own, assigned to the type of vehicle. The study presents a part of research carried out in the Department of Rail Vehicles of University of Technology in Poznan, in terms of comprehensive description of the interaction of light rail vehicle – track in a highly urbanized environment. In this range, the crucial becomes an analysis of vibroacoustic activity of the tram, which is presented here.

12

System do wspomagania pomiarów akustycznych

60%

Mężyk J. , Zbrowski A. , Flach A.

|

tom nr 11

60--64

PL

W artykule zaprezentowano system do wspomagania pomiarów akustycznych prowadzonych w komorze pogłosowej. Jego zadaniem jest pozycjonowanie próbek badanych materiałów rozpraszających dźwięk względem źródeł dźwięku i mikrofonów pomiarowych. Zaprezentowano konstrukcję mechaniczną urządzenia, zasadę sterowania nim oraz przykładowe wyniki pomiarów. Urządzenie zaprojektowano tak, aby jego wpływ na warunki akustyczne w komorze był jak najmniejszy.

EN

The article presents the system for automated acoustic measurements taken In an anechoic chamber Its task is to position the samples of tested sound dif-fusing materials related to the sources of sounds and the measurement microphones. The mechanical construction of the deyjce is presented as well as ttie principle of its control and the sample results of measurements. The design of the system is aimed at as little effect on the acoustic conditions in the chamber as possible.

13

Pomiary prędkości propagacji podłużnej i poprzecznej fali sprężystej w próbach okruchowych oraz ocena przynależności litologicznej skał w oparciu o ich widmo rezonansowe

60%

Falkowicz S. , Budak P. , Nabielec J. , Kubala A.

Nafta-Gaz

|

2006

|

tom R. 62, nr 6

290-298

PL

W artykule zaprezentowano podstawy laboratoryjnej techniki pomiaru prędkości propagacji podłużnej i poprzecznej fali sprężystej w próbach okruchowych. Przedstawiono zalety i ograniczenia tej techniki oraz wyniki pomiarów wykonanych na wybranych losowo 20 próbkach okruchowych. Zaprezentowano zarys nowej metody oceny niektórych własności skał w oparciu o analizę widma rezonansowego.

EN

The special Continuous Wave Technique (CWT) enable direct measurements of acoustic velocities [primary (P-wave) and shear or secondary (S-wave)] on small rock samples, in particular cuttings, at ultrasonic frequencies. Velocity data can be used, among others, for while-drilling prediction and evaluation of pore pressure, and some of mechanical properties of rocks. This paper presents the new method for rock's lithology identification based on resonance curves comparison

14

Zastosowanie techniki rezonansu w pomiarach akustycznych na próbkach okruchowych - nowy sposób oceny właściwości skał

60%

Falkowicz S. , Budak P. , Stadtmuller M. , Kubala A. , Myśliwiec M.

|

tom nr 130

347--351

PL

Zaprezentowano podstawy teoretyczne i zarys laboratoryjnej techniki pomiaru prędkości propagacji podłużnej i poprzecznej fali sprężystej w próbach okruchowych. Przedstawiono zalety i ograniczenia tej techniki oraz wyniki pierwszych pomiarów wykonanych na wybranych losowo 20 próbkach okruchowych. Wskazano możliwości wykorzystania wyników pomiarów w geofizyce, sejsmice i wiertnictwie oraz korzyści ekonomiczne wynikające z zastosowania tej metody pomiarowej.

EN

Presented are theoretical foundation and laboratory procedures of velocity determination of primary and secondary waves on drilling cuttings. The paper provides results for randomly selected 20 rock samples. Presented are advantages and disadvantages of this technique and possibilities of using the results in well logging, seismic soundings and drilling engineering.

15

Projektowe i rzeczywiste wartości izolacyjności akustycznej w budynkach

60%

Jabłoński M.

Fizyka Budowli w Teorii i Praktyce

|

2009

|

tom T. 4

61-68

PL

W pracy wytypowano kilka rozwiązań projektowych, dla których przewidziano w sposób teoretyczny, znanymi metodami, izolacyjność akustyczną wynikającą z założeń projektu oraz z przyjetych rozwiązań materiałowych- konstrukcyjnych. Następnie dla tych samych przegród, w warunkach rzeczywistych, pomierzono izolacyjność akustyczną wcześniej analizowanych przegród i porównano ją z obliczoną teoretycznie na etapie projektowania.

EN

In this paper several design solution were identified, for which, the known methods, acoustic insulation was predicted. This acoustic insulation due to the design assumptions and the solutions adopted materials. Then, for the same partitions, for real conditions, acoustic insulation was measured and compared to calculated theoretically.

16

Działalność Głównego Urzędu Miar w dziedzinie akustyki i drgań

60%

Dobrowolska D. , Kolasa J.

Metrologia i Probiernictwo : biuletyn Głównego Urzędu Miar

|

2018

|

tom nr 2 (21)

36--39

PL

W pracy przedstawiono w zarysie ponad 40-letnią historię działalności Głównego Urzędu Miar w dziedzinie akustyki i drgań mechanicznych. Obecne możliwości GUM w zakresie zapewnienia spójności pomiarowej przedstawiono na tle potrzeb społecznych i gospodarczych Polski w tych dziedzinach. Wskazano obszary wymagające rozwoju na drodze prac badawczo-rozwojowych, zapisanych w strategii GUM.

EN

The paper outlines the over 40-year history of the activity of the Central Office of Measures in the field of acoustics and mechanical vibrations. The current GUM’s ability to ensure traceability is presented against the background of Poland’s social and economic needs in these areas. Areas that require development through research and development work, as enshrined in the GUM strategy, were indicated.

17

Wykorzystanie badań laboratoryjnych w kalibracji pomiarów akustycznych w otworach wiertniczych

60%

Cebulski D. , Baudzis A. , Marzec D.

Prace Naukowe Instytutu Nafty i Gazu

|

2010

|

tom nr 170 wyd. konferencyjne

727--731

PL

Prędkości propagacji fal akustycznych mierzone w nasyconych ośrodkach skalnych zależą m.in. od częstotliwości sygnału wykorzystywanego podczas pomiaru. Z tego powodu istnieją rozbieżności pomiędzy pomiarami wykonanymi przy użyciu sygnału o częstotliwościach sejsmicznych, akustycznych lub ultradźwiękowych. Jednak przyjmując pewne modele oraz dysponując pomiarami ultradźwiękowymi na rdzeniach można wyznaczać prędkości dla niższych częstotliwości. W pracy podjęto próbę wyznaczenia w warunkach laboratoryjnych prędkości propagacji fal podłużnych i poprzecznych na rdzeniach wiertniczych oraz odniesienie tych pomiarów do interpretacji opartej na pomiarach akustycznych wykonanych w otworach wiertniczych.

EN

Velocity of acoustic wave propagation measured in saturated rock depends on factors such as among others frequency used during the measurement. For this reason, there are differences between measurements performed using seismic, acoustic or ultrasonic signal frequency. However, assuming certain models and having the ultrasound measurements carried out on cores you can set the velocities for lower frequencies. The study attempts to determine in the laboratory propagation velocities of longitudinal and shear waves in cores and to make the results a comparison with the interpretation of acoustic measurements performed in boreholes.

18

Od „badań profilaktycznych” do diagnostyki technicznej transformatorów

51%

Partyga S.

Śląskie Wiadomości Elektryczne

|

2005

|

tom Nr 3 (60)

18--19

PL

W artykule przedstawiono sposób oceny stanu technicznego transformatorów po drugiej wojnie światowej, na podstawie "badań profilaktycznych" opartych o pomiary tzw. Wskaźników izolacji, oraz trudności, jakie wówczas występowały przy interpretacji wyników pomiarów. " Autor opisuje przejście od okresu obowiązywania przepisów o pomiarach profilaktycznych do wprowadzenia nowoczesnej diagnostyki technicznej transformatorów.

EN

The paper describes methods of transformer testing at side, after the second world war. The so called .preventive testing" based on measurement of insulation figures, from the beginning were criticized due to the weak basement to proper transformer condition judgment. Author presents evolution from the period of obligatory “preventive testing" practice to modem transformer diagnostic testing system.

19

Pomiary elektryczne i akustyczne wykonywane w kierunkowych i poziomych otworach wiertniczych (w trakcie wiercenia) w porównaniu z klasycznymi metodami stosowanymi w otworach pionowych

51%

Bała M.

Prace Instytutu Nafty i Gazu

|

2008

|

tom nr 152

185--217

20

Wpływ położenia mikrofonu na jakość widma ciśnienia akustycznego w turbinie osiowej

51%

Ciepłucha J. , Gorząd P.

Zeszyty Naukowe. Elektryka / Politechnika Łódzka

|

2001

|

tom z. 99

15-21

PL

W pracy przedstawiono stanowisko badawcze, oprzyrządowanie i wyniki pomiarów akustycznych we wnętrzu i na zewnątrz dwustopniowej turbiny osiowej przy różnych częstościach jej pracy. Zarejestrowane sygnały ciśnienia akustycznego przedstawiono w postaci estymat widma gęstości mocy wyznaczonych zmodyfikowaną metodą Welch'a.

EN

An experimental stand, instrumentation and results of the acoustic measurements carried out inside and outside the two-stage axial turbine at different rotational speeds are presented. The acoustic pressure signals recorded during the investigation are shown in the form of estimates of the power spectrum density that were determined with the modified Welch's method.