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Tytuł:
Expressions of shallow gas in the Gdansk Basin
Różnorodność form (przejawy obecności) występowania gazu w osadach Basenu Gdańskiego
Autorzy:
Majewski, P.
Klusek, Z.
Powiązania:
https://bibliotekanauki.pl/articles/222655.pdf
Data publikacji:
2011
Wydawca:
Akademia Marynarki Wojennej. Wydział Dowodzenia i Operacji Morskich
Tematy:
gaz
metan
osady morskie
Basen Gdański
anomalie akustyczne
kratery gazowe
Bałtyk
gas
methane
marine sediments
Gdańsk Basin
acoustic anomalies
gas pockmarks
Balic
Opis:
In the paper, a short introduction to present-day acoustic and seismoacoustic inventory of shallow gas occurrence and its expression in the Gdansk Basin is presented. Signals of various frequencies and beamforming were employed during surveys conducted from the board of r/v ‘Oceania’. Such a set of diverse acoustic signals was exploited in order to obtain a better recognition of different forms of shallow gas existence in the area. The utilized frequency started from about 1 kHz once a boomer was used in sounding, up to 40–60 kHz in the case a chirp echosounder. At acoustic transects classical echosounders working at 12 and 38 kHz were applied. Some details of the qualitative analysis and the technicalities of the algorithms are given. Variety of examples of echo images obtained in different frequency bands, associated with different forms of gas occurrence is presented.
W artykule dokonano wprowadzenia do współcześnie prowadzonych metodami akustycznymi detekcji i rozpoznawania różnorodności postaci występowania gazu w osadach dennych Basenu Gdańskiego. W celach lepszego rozpoznania form występowania gazu w górnej warstwie osadów w rejsach badawczych r/v „Oceanii” zastosowano sondowanie dna za pomocą sygnałów akustycznych zróżnicowanych pod względem częstotliwości oraz ukształtowania wiązki. Zakres częstotliwości sygnałów akustycznych wykorzystanych w sondowaniu dna zawierał się w granicach od około 1 kHz (boomer) poprzez 12/38 kHz do szerokopasmowych w granicach 40–80 kHz. Na wielu transektach akustycznych do obrazowania ukształtowania dna i warstwy naddanej zastosowano również sonar boczny i echosondę wielowiązkową. W artykule przedstawiono niektóre elementy analizy jakościowej oraz przybliżono szczegóły techniczne algorytmów pozwalających na identyfikację gazu w osadach. Zaprezentowano także liczne przykłady obrazów echa otrzymane dla sygnałów akustycznych w różnych pasmach częstotliwości, powiązanych z występowaniem gazu w osadach.
Źródło:
Zeszyty Naukowe Akademii Marynarki Wojennej; 2011, R. 52 nr 4 (187), 4 (187); 61-71
0860-889X
Pojawia się w:
Zeszyty Naukowe Akademii Marynarki Wojennej
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Parameters of echo signals originated from a gas seepage site in the Southern Baltic Sea
Autorzy:
Majewski, P.
Klusek, Z.
Powiązania:
https://bibliotekanauki.pl/articles/331854.pdf
Data publikacji:
2014
Wydawca:
Polskie Towarzystwo Akustyczne
Opis:
Gaseous shallow sediment has been recognized in several areas of the Southern Baltic Sea. The most commonly observed manifestation of the gas in the bottom top layer is an acoustic blanking or shadowing resulting from significant attenuation and scattering of acoustic signals in the regions of gas bubble occurrence at the bottom. The main goal of this publication was to examine whether known methods of acoustic echo parameterization generally used to determine the fraction of the surface deposits would be sufficient in determining the extent of the occurrence of gas saturated sediments and areas with periodic gaseous outflows. To this end, a set of an acoustic echo signals recorded in gas seepage regions by using four different frequencies (12, 70, 120 and 200 kHz) was analyzed. To determine the acoustic features of gaseous sediments, based on the shape of the echo envelope, a few statistical parameters, as well as the parameters resulting from a wavelet transform, were calculated. A comparison of the results allowed for a relatively accurate separation of pockmark areas.
Źródło:
Hydroacoustics; 2014, 17; 143-150
1642-1817
Pojawia się w:
Hydroacoustics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
CW and CHIRP signals bottom backscattering in the PEZ of the Baltic sea
Autorzy:
Klusek, Z.
Majewski, P.
Dragan, A.
Powiązania:
https://bibliotekanauki.pl/articles/331941.pdf
Data publikacji:
2010
Wydawca:
Polskie Towarzystwo Akustyczne
Opis:
High-frequency bottom backscattering experiments were carried out in the Polish Economy Zone of the Southern Baltic Sea. CW and chirp signals were used to determine scattering reverberation as a function of the incident wave grazing angle and at vertical sounding. The chirp signals covered the frequency range from 40 to 80 kHz whilst the CW signals were selected at 40, 60 and 80 kHz. Acoustic data concerning the angular dependence of the backscattering were taken at the points where appropriate investigations of sediment properties had been earlier made by the Polish Geology Institute. The sediment types include not only acoustically hard fine and coarse sand bottom covered with gravel but also a flat muddy bottom. The results present the backscattering as a function of frequency, signal type and sediments properties. Times of reverberation and other statistical properties of returned signal are also discussed. When possible, due to more complete information on the sediments properties the measured backscattering strength was compared to the models developed by Jackson et al.
Źródło:
Hydroacoustics; 2010, 13; 135-142
1642-1817
Pojawia się w:
Hydroacoustics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Detection damage in bearing system of jet engine using the vibroacoustic method
Autorzy:
Żokowski, M.
Majewski, P.
Spychała, J.
Powiązania:
https://bibliotekanauki.pl/articles/970580.pdf
Data publikacji:
2017
Wydawca:
Politechnika Białostocka. Oficyna Wydawnicza Politechniki Białostockiej
Tematy:
jet engine
damage of bearing
vibroacoustic method
envelope method
Opis:
The article discusses typical, operational systems for monitoring vibrations of jet engines, which constitute the propulsion of combat aircraft of the Armed Forces of the Republic of Poland. After that, the paper presents the stage of installing vibration measuring sensors in the direct area of one of the jet engine bearings, which is a support system for its rotor. The article discusses results of carried out analyses of data gathered during tests of the engine in the conditions a jet engine test bed. Results of detecting damages to the bearing, using sensors built in the direct area will be presented.
Źródło:
Acta Mechanica et Automatica; 2017, 11, 3; 237-242
1898-4088
2300-5319
Pojawia się w:
Acta Mechanica et Automatica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Comcutejs:a Web browser based platform for large-scale computations
Autorzy:
Dębski, R.
Krupa, T.
Majewski, P
Powiązania:
https://bibliotekanauki.pl/articles/305741.pdf
Data publikacji:
2013
Wydawca:
Akademia Górniczo-Hutnicza im. Stanisława Staszica w Krakowie. Wydawnictwo AGH
Tematy:
volunteer computing
parallel computations
large-scale computations
augmented cloud computing
Opis:
The paper presents a new, cost effective,volunteer computing based platform. It utilizes volunteers’web browsers as computational nodes. The computational tasks are delegated to the browsers and executed in the background (independently of any user interface scripts) making use of the HTML5 web workers technology. The capabilities of the platform hale been proved by experiments performer in a wide range of numbers of computational nodes (1–400).
Źródło:
Computer Science; 2013, 14 (1); 143-152
1508-2806
2300-7036
Pojawia się w:
Computer Science
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Explicit form of the “modified point mass trajectory model” for the use in Fire Control Systems
Autorzy:
Baranowski, L.
Majewski, P.
Szymonik, J.
Powiązania:
https://bibliotekanauki.pl/articles/200333.pdf
Data publikacji:
2020
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
ballistics
equations of motion
projectile path
modified point mass trajectory model
MPMTM
projectile deflection
Opis:
The main objective of this article is to obtain equations of motion of the spin–stabilized projectile in the presence of non–constant wind. Introducing models allowing utilization of inhomogeneous wind is dictated by new possibilities created by the use of e.g. lidars in the Fire Control Systems (FCS). Constant feed of wind data can replace meteorological messages, increasing the FCS effectiveness. Article contains results of projectile flight simulations which indicate the positive effect that the derived explicit form of the model has when considering software development for modern Fire Control Systems.
Źródło:
Bulletin of the Polish Academy of Sciences. Technical Sciences; 2020, 68, 5; 1167-1175
0239-7528
Pojawia się w:
Bulletin of the Polish Academy of Sciences. Technical Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Some problems with vibroacoustic method in relation to the transmission gearbox of a military helicopter
Autorzy:
Majewski, P.
Spychała, J.
Żokowski, M.
Powiązania:
https://bibliotekanauki.pl/articles/196884.pdf
Data publikacji:
2016
Wydawca:
Politechnika Śląska. Wydawnictwo Politechniki Śląskiej
Tematy:
transmission gear
vibroacoustics
gearbox
helicopter
przekładnia
wibroakustyka
skrzynia biegów
śmigłowiec
Opis:
The article presents the results of a laboratory gear stage with regard to deepening its consumption. In addition, the study looked at the construction of the transmission gearbox of a military helicopter, according to the basic kinematic results of the analysis of vibroacoustic signals, in order to determine the diagnostic criteria for the assessment of the technical condition of a military helicopter’s transmission gearbox.
Źródło:
Zeszyty Naukowe. Transport / Politechnika Śląska; 2016, 93; 79-90
0209-3324
2450-1549
Pojawia się w:
Zeszyty Naukowe. Transport / Politechnika Śląska
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Geochemical and acoustic evidence for the occurrence of methane in sediments of the Polish sector of the Southern Baltic Sea
Autorzy:
Brodecka, A.
Majewski, P.
Bolalek, J.
Klusek, Z.
Powiązania:
https://bibliotekanauki.pl/articles/48640.pdf
Data publikacji:
2013
Wydawca:
Polska Akademia Nauk. Instytut Oceanologii PAN
Tematy:
methane
sulphate concentration
hydrogen sulphide
sediment
Baltic Sea
marine sediment
shallow sea
organic matter decomposition
water parameter
acoustic property
Źródło:
Oceanologia; 2013, 55, 4
0078-3234
Pojawia się w:
Oceanologia
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Comparison of explicit and implicit forms of the modified point mass trajectory model
Autorzy:
Baranowski, L.
Gadomski, B.
Szymonik, J.
Majewski, P.
Powiązania:
https://bibliotekanauki.pl/articles/280031.pdf
Data publikacji:
2016
Wydawca:
Polskie Towarzystwo Mechaniki Teoretycznej i Stosowanej
Tematy:
exterior ballistics
projectile motion
MPMTM
equations of motion
projectile trajectory
Opis:
The article compares the results of trajectory computation for a 35 mm projectile using two forms (explicit and implicit) of the modified point-mass trajectory model. All necessary ammunition parameters (aerodynamic coefficients, dimensions, mass etc.) and initial conditions for differential equations are provided. The results of numerical integration (using non-stiff fourth-order Runge-Kutta solver) are presented in form of projectile trajectories projections onto vertical and horizontal planes. Data tables comparing both models in terms of projectile position and velocity in chosen time steps are also attached.
Źródło:
Journal of Theoretical and Applied Mechanics; 2016, 54, 4; 1183-1195
1429-2955
Pojawia się w:
Journal of Theoretical and Applied Mechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
System for bistatic measurements of reverberations in the shallow sea area
Autorzy:
Klusek, Z.
Elminowicz, A.
Majewski, P.
Dragan, A.
Powiązania:
https://bibliotekanauki.pl/articles/331817.pdf
Data publikacji:
2011
Wydawca:
Polskie Towarzystwo Akustyczne
Opis:
In the paper a system for measurements of reverberations in the shallow sea environment is presented. The setup operated in 40–80 kHz frequency range with pseudomonochromatic pulses or chirp signal and has possibility to acquire bistatic scattered data. The system is constructed in such manner that depending on an experiment configuration we could perform measurements of the local 3D scattering strength of the bottom and/or far range bistatic reverberations from the sea surface, volume inhomogeneities and sea bottom. The final objective of the system is to give prognosis for probability of target detections when using bior multistatic barriers. Details of the individual blocks are given in the following sections and the technicalities of the design are given. Furthermore, some examples of data gathered during test of the equipment concerning assessment of the reverberation and local bistatic scattering features are presented.
Źródło:
Hydroacoustics; 2011, 14; 83-90
1642-1817
Pojawia się w:
Hydroacoustics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Preliminary investigations on implementation of technology of broadband signals for marine biology and sediments recognition
Autorzy:
Klusek, Z.
Majewski, P.
Dragan, A.
Psuty, I.
Powiązania:
https://bibliotekanauki.pl/articles/331938.pdf
Data publikacji:
2010
Wydawca:
Polskie Towarzystwo Akustyczne
Opis:
This paper describes potential applications of broadband acoustic signals for marine biology and fisheries and acoustic precise profiling of the upper layer of sediments. Comparisons of the results of conducted experiments employing the same experimental setup but with different signals are presented. In each of experiments short pulses of CW signals and long pulses of up/down chirp signals were used. The basic theory of FM signals as well as some of the factors that must be considered when implementing this type of signal in actual systems are described.
Źródło:
Hydroacoustics; 2010, 13; 143-152
1642-1817
Pojawia się w:
Hydroacoustics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
35 mm ammunition’s trajectory model identification based on firing tables
Autorzy:
Baranowski, L.
Gadomski, B.
Majewski, P.
Szymonik, J.
Powiązania:
https://bibliotekanauki.pl/articles/200598.pdf
Data publikacji:
2018
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
identification
exterior ballistics
equations of projectile motion
curve fitting
drag coefficient
identyfikacja
ruch pocisku
współczynnik oporu
Opis:
The article presents a procedure designed for identification of projectile’s trajectory model through aerodynamic coefficients estimation. The identification process is based on firing tables artificially prepared (firing tables prepared using mathematical flight model for the projectile instead of trajectories recorded on field tests) with the use of modified point–mass and rigid body trajectory models. All the necessary data, including physical parameters of the projectile and its aerodynamic characteristics are provided. The detailed results of estimation of chosen aerodynamic coefficients are presented in both visual and tabular form. The main purpose of this paper is to establish the minimum number of trajectories (as characterized in firing tables), and the permissible error of initial parameters being passed to the mathematical model that would allow the correct identification of projectile’s trajectory model.
Źródło:
Bulletin of the Polish Academy of Sciences. Technical Sciences; 2018, 66, 5; 635-643
0239-7528
Pojawia się w:
Bulletin of the Polish Academy of Sciences. Technical Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Explicit “ballistic M-model”: a refinement of the implicit “modified point mass trajectory model”
Autorzy:
Baranowski, L.
Gadomski, B.
Majewski, P.
Szymonik, J.
Powiązania:
https://bibliotekanauki.pl/articles/202089.pdf
Data publikacji:
2016
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
ballistics
equations of motion
projectile path
modified point mass trajectory model
MPMTM
projectile deflection
balistyka
równania ruchu
lot pocisku
Opis:
Various models of a projectile in a resisting medium are used. Some are very simple, like the “point mass trajectory model”, others, like the “rigid body trajectory model”, are complex and hard to use, especially in Fire Control Systems due to the fact of numeric complexity and an excess of less important corrections. There exist intermediate ones - e.g. the “modified point mass trajectory model”, which unfortunately is given by an implicitly defined differential equation as Sec. 1 discusses. The main objective of this paper is to present a way to reformulate the model obtaining an easy to solve explicit system having a reasonable complexity yet not being parameter-overloaded. The final form of the M-model, after being carefully derived in Sec. 2, is presented in Subsec. 2.5.
Źródło:
Bulletin of the Polish Academy of Sciences. Technical Sciences; 2016, 64, 1; 81-89
0239-7528
Pojawia się w:
Bulletin of the Polish Academy of Sciences. Technical Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Web pages content analysis using browser-based volunteer computing
Autorzy:
Turek, W.
Nawarecki, E.
Dobrowolski, G.
Krupa, T.
Majewski, P.
Powiązania:
https://bibliotekanauki.pl/articles/305311.pdf
Data publikacji:
2013
Wydawca:
Akademia Górniczo-Hutnicza im. Stanisława Staszica w Krakowie. Wydawnictwo AGH
Tematy:
volunteer computing
text processing
web crawling
Opis:
Existing solutions to the problem of finding valuable information on the Web suffers from several limitations like simplified query languages, out-of-date in- formation or arbitrary results sorting. In this paper a different approach to this problem is described. It is based on the idea of distributed processing of Web pages content. To provide sufficient performance, the idea of browser-based volunteer computing is utilized, which requires the implementation of text processing algorithms in JavaScript. In this paper the architecture of Web pages content analysis system is presented, details concerning the implementation of the system and the text processing algorithms are described and test results are provided.
Źródło:
Computer Science; 2013, 14 (2); 215-230
1508-2806
2300-7036
Pojawia się w:
Computer Science
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
New trends in application of the fumigation method in medical and non-medical fields
Autorzy:
Bukłaha, A.
Wieczorek, A.
Majewski, P.
Iwaniuk, D.
Sacha, P.
Tryniszewska, E.
Wieczorek, P.
Powiązania:
https://bibliotekanauki.pl/articles/28761854.pdf
Data publikacji:
2022
Wydawca:
Instytut Medycyny Wsi
Źródło:
Annals of Agricultural and Environmental Medicine; 2022, 29, 2; 185-189
1232-1966
Pojawia się w:
Annals of Agricultural and Environmental Medicine
Dostawca treści:
Biblioteka Nauki
Artykuł

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