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Wyszukujesz frazę "46.40.-f" wg kryterium: Temat


Tytuł:
The Focused Beam Forming with a Monolithic 2D Phased Array
Autorzy:
Lila, B.
Kapelewski, J.
Powiązania:
https://bibliotekanauki.pl/articles/1811538.pdf
Data publikacji:
2008-12
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
46.40.-f
43.58.+z
Opis:
A new type of the monolithic acoustic scanner based on a near-surface quasicomposite two-dimensional array, implemented in the solid elastic substrate was proposed. It provides a simple means of focusing and scanning a beam of acoustic waves, radiated into the depth of the elastic solid substrate. A chirped surface acoustic wave is converted into a focused bulk wave by scattering from an array composed of a 2D periodic system of regions with varying material parameters, located at the surface of a surface acoustic waves substrate. In the paper, a simple numerical simulation model is presented to analyse the influences of the dynamical and geometrical parameters of the surface structure, as well as the influences of incident surface acoustic waves signal profile on the focal distribution.
Źródło:
Acta Physica Polonica A; 2008, 114, 6A; A-151-A-155
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Hardware Implementation of Artificial Neural Networks for Vibroacoustic Signals Classification
Autorzy:
Dąbrowski, D.
Jamro, E.
Cioch, W.
Powiązania:
https://bibliotekanauki.pl/articles/1537403.pdf
Data publikacji:
2010-07
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
45.80.+r
46.40.-f
Opis:
This paper studies the architecture of a neural classifier designed to identify technical condition of machines, based on vibroacoustic signals. The designed neural network is optimized for implementation on Field Programmable Gate Arrays (FPGA) programmable devices. FPGA allows massive parallelism and thus real-time classification as each neuron can execute arithmetic operations simultaneously. The classifier of vibroacoustic signals was designed and tested for the self - organized neural network. The teaching vectors are based on estimates derived from processed vibroacoustic signals generated by rotary machines. The created classifier was applied for recognizing technical state of demonstrative toothed gear DMA1 in variable operating conditions.
Źródło:
Acta Physica Polonica A; 2010, 118, 1; 41-44
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Searching for New Measurement Solutions in the Area οf Estimating Danger of Local Vibrations at Workplace
Autorzy:
Barański, R.
Powiązania:
https://bibliotekanauki.pl/articles/1537332.pdf
Data publikacji:
2010-07
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
07.10.-h
46.40.-f
Opis:
There is a lot of controversy when we consider the most popular method of measuring local vibrations to estimate danger on hand tools operators. This is because of commonly used adapter that represents many faults, from which the most significant are: strong impact of grip and placing adapter between a hand and a tool handle. What we propose in this article is a measurement system including a band placed on a wrist. This solution highly eliminates defects mentioned above, but seems to be too trivial to maintain high quality of measuring process. The purpose of this article is to estimate the quality of this new solution in respect of some basic categories in which measurement errors occur.
Źródło:
Acta Physica Polonica A; 2010, 118, 1; 3-6
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The Idea of the Selection of PZT-Beam Interaction Forces in Active Vibration Protection Problem
Autorzy:
Brański, A.
Borkowski, M.
Szela, S.
Powiązania:
https://bibliotekanauki.pl/articles/1537347.pdf
Data publikacji:
2010-07
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
46.70.De
02.60.Pn
46.40.-f
07.10.Fq
Opis:
The paper concerns an active vibration protection (p-reduction) of the structure. This problem corresponds to the active vibration reduction (a-reduction). The quantity and effectivness of the a-/p- reduction, measured with reduction and effectiveness coefficient respectively, depends on, inter alia, the PZT distribution on the structure subdomains with the largest curvatures (quasi optimal distribution) are considered. The aim of this paper is to determine such interacting forces PZT-structure, assuming QO distribution of PZTs, which maximize the effectiveness of p-reduction. The beam clamped at one end, vibrating separately with first three modes, is chosen as the research object. The interacting forces are searched requiring that the shear force and bending moment at the clamped side are equal to zero. The total p-reduction is achieved for separate modes. Assuming the QO distribution of the PZTs, the best p-effectiveness is achieved. The validation of theoretical considerations is confirmed numerically.
Źródło:
Acta Physica Polonica A; 2010, 118, 1; 17-22
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The Influence of Drivers Working Environment οn Thermical Changes of Their Organism
Autorzy:
Damijan, Z.
Uhryński, A.
Powiązania:
https://bibliotekanauki.pl/articles/1537402.pdf
Data publikacji:
2010-07
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
08.89.40.-a
46.40.-f
87.19.R-
43.80.-n
43.80.+p
Opis:
The work presents the research on the influence of driver's working environment on thermical changes in their organism. The experiment was conducted between 24 and 31 March 2008 in the tram depot of Public Transport Agency in Tychy. Thermo-visual photos were conducted twice a day - before starting work and after finishing it during six following days. The group consisted of 14 drivers aged 24-49 driving city buses (the make: Solaris Urbino 18). The results were analyzed concerning statistics using Statistica. For the sake of the analysis the significance level was p = 0.05, the non-parametric Wilcoxon test or parametric T-test were used for two groups of dependent variables. The research and analysis show that driver's working environment has valid influence on thermical changes in their organism.
Źródło:
Acta Physica Polonica A; 2010, 118, 1; 35-40
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Transformation of Nonstationary Signals into Pseudostationary Signals for the Needs of Vehicle Diagnostics
Autorzy:
Dziurdź, J.
Powiązania:
https://bibliotekanauki.pl/articles/1537406.pdf
Data publikacji:
2010-07
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
46.40.-f
46.80.+j
Opis:
Research concerning the development of diagnostic methods of the state of the vehicle driving systems basic elements - have been carried on for many years. Modern diagnostic systems, regardless of being technically highly advanced or small degree only, concern about assessments of basic mechanical subsystems such as toothed gears or suspension elements. The information on state changes of mechanical systems can be obtained by an analysis of changes of nonlinear effects in such systems operations. Since the nonlinearity increase accompanies the system destruction, the separation of nonlinear parts of signals creates the possibility of the increase of an accuracy, reliability and application range of diagnostic methods. Technical state diagnostics for vehicles is much more difficult than for machines operating in stationary conditions. the main excitation source is an internal combustion engine, in which a rotational speed changes from an idle running (approximately 800 rpm) to a maximum rotational speed (e.g. above 5000 rpm). Thus, an application of classic analytical methods is not possible. the only solution is the transformation of the analysed signals into the "pseudostationary" ones, by taking into account changes in the engine rotational speed. One of the methods applied now a days is resampling (adaptation change of a signal time resolution in a digital form) performed on the basis of information concerning changes in an engine rotational speed. the signal from the sensor of the engine crankshaft location was used for the above application.
Źródło:
Acta Physica Polonica A; 2010, 118, 1; 49-53
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Analytical Determination of the PZTs Distribution in Active Beam Vibration Protection Problem
Autorzy:
Brański, A.
Lipiński, G.
Powiązania:
https://bibliotekanauki.pl/articles/1504198.pdf
Data publikacji:
2011-06
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
43.40.Tm
43.40.Vn
77.65.-j
46.40.-f
62.25.Jk
Opis:
The paper concerns an active vibration protection (p-reduction) of the structure via piezoelectric transducers; p-reduction corresponds to an active vibration reduction (a-reduction). The quantity and effectiveness of the (a- or p-) reduction, among other parameters, depend on the piezoelectric transducers distribution on the structure. The best results are obtained bonding piezoelectric transducers to the structure in the sub-domains with the largest curvatures; it is so-called quasi-optimal distribution of the piezoelectric transducers. Up to now, the quasi-optimal distribution was determined based on heuristic reasons only. The aim of the paper is to confirm quasi-optimal distribution in analytical way. The beam clamped at one end, vibrating with first three modes separately, is chosen as the research object. It is assumed that the piezoelectric transducers are exactly the same. Demanding the vibration amplitude to be equal to zero (i.e. p-reduction condition), the general formula for interacting forces piezoelectric transducers-beam is derived. Next, such an appropriate distribution of piezoelectric transducers is searched analytically, that the minimal forces are achieved; it leads to the best reduction effectiveness. It turned out that the analytical method pointed out quasi-optimal distribution of the piezoelectric transducers. The validation of theoretical considerations is confirmed numerically.
Źródło:
Acta Physica Polonica A; 2011, 119, 6A; 936-941
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Applicability of the Fourier Expansion Method of Separation of Variables in the Linear Discrete-Continuous Systems with Distributional Coefficients
Autorzy:
Kasprzyk, S.
Powiązania:
https://bibliotekanauki.pl/articles/1504303.pdf
Data publikacji:
2011-06
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
46.70.De
46.40.-f
Opis:
The analytical examination of mechanical systems in the aspect of their vibro-isolation can be limited to the construction of a computational system. The analytical description of the adopted appropriate computational model may be executed with the help of a set of differential equations of the second order, differential equations with partial derivatives or of both types at the same time. The latest description is associated with the so-called discrete-continuous systems. It is the most convenient to analyze the vibrations of the linear discrete-continuous systems in the class of functions generalized with the Fourier method of separation of variables. Until now it was possible to execute only for a small set of parameters of the system's structure. In the work the author presents a computational model that covers all the structural parameters of the system.
Źródło:
Acta Physica Polonica A; 2011, 119, 6A; 981-985
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Design of Band-Gap Structures from Sheet Metal
Autorzy:
Iwański, D.
Wiciak, J.
Powiązania:
https://bibliotekanauki.pl/articles/1504205.pdf
Data publikacji:
2011-06
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
46.40.-f
Opis:
Two-dimensional, circular plate was taken under consideration to design a band-gap structure. The analytical model was built using the Bessel functions and at the end the numerical examples were presented using MatLab and Ansys software. Results show that it is possible to create a band-gap structure, however further verification analysis must be made to improve given solution.
Źródło:
Acta Physica Polonica A; 2011, 119, 6A; 972-976
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Investigation of the Vibroacoustic Climate inside the Buses Solaris Urbino 18 Used in Public Transport Systems - Drivers Cab
Autorzy:
Damijan, Z.
Skrzyniarz, S.
Kwaśniewski, J.
Powiązania:
https://bibliotekanauki.pl/articles/1504428.pdf
Data publikacji:
2011-06
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
89.40.-a
46.40.-f
07.10.-h
46.40.Cd
Opis:
Despite new technological solutions and attempts to improve the working conditions during driving of vehicles, city bus drivers are still exposed to negative impacts of noise and vibrations, causing stress, increased fatigue and leads to numerous diseases. Therefore it seems merited to investigate the acoustic climate and the working conditions during the operation of Solaris Urbino 18 vehicles, widely used in public transport systems. The main purpose of this research program was to show the impacts that the conditions at work might have on bus drivers or to demonstrate that these impacts do not exist. No extensive major research was done to investigate the influence of the conditions at work on functional stability of bus drivers. Investigation of vehicle vibroacoustic climate in working (normal) environment are led rarely. Measurements often are done in idle run or during ride at manoeuvring site only for 2-3 min. In this paper results of acceleration and noise in idle run are presented for 3 min measurement and for 3 h until ride. All measurements are done in working environment on streets of Tychy city with passengers on board. In this paper detailed numerical analysis of vibroacoustic parameters are presented. Physical parameters like noise spectral analysis in 1/3 octave frequency bands and histogram of acoustic pressure level in the driver's cabin are presented in results.
Źródło:
Acta Physica Polonica A; 2011, 119, 6A; 1068-1072
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Neural Classifiers of Vibroacoustic Signals in Implementation on Programmable Devices (FPGA) - Comparison
Autorzy:
Dąbrowski, D.
Cioch, W.
Powiązania:
https://bibliotekanauki.pl/articles/1504200.pdf
Data publikacji:
2011-06
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
45.80.+r
46.40.-f
Opis:
The research includes comparative analysis of the effect of the recording of weight vectors and input data of selected neural classifiers with fixed-point numbers. Research has been conducted due to insufficient literature on the influence of such a recording on the correct classification of vibroacoustic signals by neural networks. This current issue was brought up in authors' earlier researches, concerning realization of neural classifiers on programmable logical devices field programmable gate array, with the application of fixed-point processor. During the analysis, three types of neural classifiers were compared in the tests: classifier based on neural network - length vector quantization, classifier using radial neural networks - radial basis functions, and third - counter propagation neural network. The problem stated was to recognize technical state of gear transmission DMA-1 in variable operating conditions. Vectors, based on estimates derived from processed vibroacoustic signals were used as teaching material.
Źródło:
Acta Physica Polonica A; 2011, 119, 6A; 946-949
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The Concept of a System for Identification of the Dangerous Areas for People with Visual Dysfunction
Autorzy:
Wiciak, J.
Borkowski, B.
Powiązania:
https://bibliotekanauki.pl/articles/1504188.pdf
Data publikacji:
2011-06
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
41.20.-q
46.40.-f
Opis:
The article presents the concept of a system for identification of dangerous areas in the urban area targeted at the people with visual dysfunction. The idea of the system is presented comprising the attempt of application of the wireless data transmission: IR - infra-red; BLUETOOTH; RFID. The consideration comprises also the identification of the object (human), identification of the movement direction (double barrier), wireless data transmission with data on the given dangerous area, excitation of the vibration information and the feedback of the system. Also the subject of optimal installation on the urban objects was discussed. The article is a realisation of the research task in the project called "The development of the method for marking of the dangerous areas and especially important places in urban area for visually impaired people with use of the wave-vibration markers".
Źródło:
Acta Physica Polonica A; 2011, 119, 6A; 921-924
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The Spectral Response of Hand-Arm System
Autorzy:
Barański, R.
Batko, W.
Powiązania:
https://bibliotekanauki.pl/articles/1504183.pdf
Data publikacji:
2011-06
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
07.10.-h
46.40.-f
Opis:
Recently we have used better solution to protect hand tool operators. In spite of our good intentions there is still endanger on high level vibration. For that reason we need to improve protection constantly. One of the most important properties of hand-arm system is knowledge about spectral response. In this article we try to obtain spectral response in narrow band-pass filters in accordance with IEC 1260:1995 and ANSI S1.11-2004 standards (implemented in LabVIEW software). To measure signals we used accelerometer placed on a wrist and on a tool. Of course the vibrations are attenuated by hand (cartilage, muscular tissue) but the question was what the shape of envelope in measurement range is. Our research used measurement on two different systems. The one was based on vibration inductor (laboratory environment), the second one used drill (real environment). This research is a part of a wider project to make virtual model of hand-arm system.
Źródło:
Acta Physica Polonica A; 2011, 119, 6A; 913-915
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Construction of Equivalent Models of Continuous and Discrete-Continuous Systems
Autorzy:
Kasprzyk, S.
Marczuk, R.
Powiązania:
https://bibliotekanauki.pl/articles/1490367.pdf
Data publikacji:
2012-01
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
46.70.De
46.40.-f
Opis:
New models have been constructed for three physical systems. These models are characterized by a uniform and transparent mathematical description. The mathematical description belongs to the class of generalized functions, which means that all equations as well as their solutions are understood in the sense of weak topology. The elements of the set of generalized functions need not be differentiable (in the classical sense) at each point domain of the function. Analyzing of actual systems in the class of generalized functions does not require a division into subsystems, which simplifies significantly execution of all mathematical operations. As compared with the classical methods, those presented in the study allow for a much faster achievement of the goal.
Źródło:
Acta Physica Polonica A; 2012, 121, 1A; A-191-A-196
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Hamiltonian Approach to Multiple Coupled Nonlinear Oscillators
Autorzy:
Durmaz, S.
Altay Demirbag, S.
Kaya, M.
Powiązania:
https://bibliotekanauki.pl/articles/1490743.pdf
Data publikacji:
2012-01
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
05.45.-a
46.40.-f
Opis:
In this paper, Hamiltonian approach is extended to investigate coupled nonlinear multi-degree-of-freedom oscillatory systems. At the beginning of the study, basic principles of Hamiltonian approach are provided for multiple coupled oscillators. In the next section, the amplitude-frequency relation for the two-degree-of-freedom nonlinear mechanical systems is obtained via Hamiltonian approach. The natural frequency expression is compared to show the agreement between the present and published results. Additionally, the approximate and numerical periodic solutions are plotted.
Źródło:
Acta Physica Polonica A; 2012, 121, 1; 47-49
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł

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