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Wyszukujesz frazę "low frequency" wg kryterium: Temat


Tytuł:
Noise spectroscopy of resistive components at elevated temperature
Autorzy:
Stadler, A.W.
Zawiślak, Z.
Dziedzic, A.
Nowak, D.
Powiązania:
https://bibliotekanauki.pl/articles/221348.pdf
Data publikacji:
2014
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
noise spectroscopy
low-frequency noise
resistance noise
low-frequency noise measurements
thick-film resistors
Opis:
Studies of electrical properties, including noise properties, of thick-film resistors prepared from various resistive and conductive materials on LTCC substrates have been described. Experiments have been carried out in the temperature range from 300 K up to 650 K using two methods, i.e. measuring (i) spectra of voltage fluctuations observed on the studied samples and (ii) the current noise index by a standard meter, both at constant temperature and during a temperature sweep with a slow rate. The 1/f noise component caused by resistance fluctuations occurred to be dominant in the entire range of temperature. The dependence of the noise intensity on temperature revealed that a temperature change from 300 K to 650 K causes a rise in magnitude of the noise intensity approximately one order of magnitude. Using the experimental data, the parameters describing noise properties of the used materials have been calculated and compared to the properties of other previously studied thick-film materials.
Źródło:
Metrology and Measurement Systems; 2014, 21, 1; 15-26
0860-8229
Pojawia się w:
Metrology and Measurement Systems
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A Study of Annoyance Caused by Low-Frequency Noise During Mental Work
Autorzy:
Kaczmarska, A.
Łuczak, A.
Powiązania:
https://bibliotekanauki.pl/articles/89879.pdf
Data publikacji:
2007
Wydawca:
Centralny Instytut Ochrony Pracy
Tematy:
low-frequency noise
annoyance
working environments
Opis:
This article presents the results of an analysis of annoyance caused by low-frequency noise (including infrasonic noise) that occurs at work stations located in offices. The tests covered measurements of acoustic parameters specific for this type of noise and a survey conducted in the working environment and in laboratory conditions at a model of a work station.
Źródło:
International Journal of Occupational Safety and Ergonomics; 2007, 13, 2; 117-125
1080-3548
Pojawia się w:
International Journal of Occupational Safety and Ergonomics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Reflection of low-frequency long-range sound in the ocean
Autorzy:
Didenkulov, I.
Powiązania:
https://bibliotekanauki.pl/articles/332043.pdf
Data publikacji:
2003
Wydawca:
Polskie Towarzystwo Akustyczne
Tematy:
low frequency
long-range
sound
ocean
underwater
Opis:
Experimental results on energetic characteristics of low frequency (about 200 Hz) underwater channel sound reflection by ocean mountains and islands are presented. lt is investigated also sound penetration into shallow water. Transformation of vertical structure of sound field over continental slope is considered. Continental slope and shelf-wedge reflection coefficients of law frequency sound propagating in the underwater waveguide were measured. Results of the work show that low-frequency sound reflections from large-scale bottom irregularities can be important in ocean acoustics.
Źródło:
Hydroacoustics; 2003, 6; 117-124
1642-1817
Pojawia się w:
Hydroacoustics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Analiza termowizyjna zmian temperatury kończyn dolnych pod wpływem drgań ogólnych niskiej częstotliwości
Thermovision analysis of temperature changes in lower extremities after exposing to general low frequency vibrations
Autorzy:
Krzyworzeka, P.
Uhryński, A.
Powiązania:
https://bibliotekanauki.pl/articles/261640.pdf
Data publikacji:
2009
Wydawca:
Politechnika Wrocławska. Wydział Podstawowych Problemów Techniki. Katedra Inżynierii Biomedycznej
Tematy:
drgania niskoczęstotliwościowe
termowizja
thermovision
low-frequency vibrations
Opis:
W pracy przedstawiono wpływ drgań niskiej częstotliwości na zmianę temperatury w obrębie kończyn dolnych. Badania odbyły się w lipcu 2006 r. w Krynicy-Zdroju. Eksperyment polegał na przeprowadzeniu 19 dwudziestominutowych treningów z wykorzystaniem drgań ogólnych niskiej częstotliwości (pozycja stojąca), o stałej porze dnia. Przed i po ekspozycji rejestrowano zdjęcia termowizyjne kończyn dolnych. Amplituda drgań niskoczęstotliwościowych wynosiła 4 mm, częstotliwość 3,5 Hz. W eksperymencie uczestniczyło 28 osób. Otrzymane wyniki poddano analizom statystycznym w środowisku Statistica. W analizach statystycznych przyjęto poziom istotności p = 0,05, zastosowano nieparametryczny test Wilcoxona oraz parametryczny test t-studenta dla dwóch grup zmiennych zależnych. Po przeprowadzeniu badań i analiz można stwierdzić, iż po 20 minutach drgań niskiej częstotliwości obserwowane są istotne zmiany temperatur kończyn dolnych.
The influence of low frequency vibrations on temperature variations in lower extremities, is analyzed. The examination was conducted in Krynica-Zdrój in July 2006. The experiment included 19 training sessions, each lasting 20 minutes. The low frequency vibration was applied to each participant in standing position at the same time each day. Before and after the session thermal images were recorded. The low frequency vibration amplitude was 4 mm, while the frequency was 3,5 Hz. 28 participants were examined. The results were analyzed by means of Statistica software. The significance level p = 0,05 was chosen, the non-parametric Wilcoxon test and the parametric t-student test were applied for two groups of dependent variables. It was stated that 20 minutes exposure to low frequency vibrations resulted in significant changes temperature distribution within lower extremities.
Źródło:
Acta Bio-Optica et Informatica Medica. Inżynieria Biomedyczna; 2009, 15, 1; 23-26
1234-5563
Pojawia się w:
Acta Bio-Optica et Informatica Medica. Inżynieria Biomedyczna
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Analysis of current noise in MOSFET-based charge-transfer device
Autorzy:
Inokawa, H.
Singh, V.
Satoh, H.
Powiązania:
https://bibliotekanauki.pl/articles/385224.pdf
Data publikacji:
2009
Wydawca:
Sieć Badawcza Łukasiewicz - Przemysłowy Instytut Automatyki i Pomiarów
Tematy:
low-frequency noise
MOSFET
charge-transfer device
Opis:
Low-frequency current noise in the MOSFET-based charge-transfer devices was evaluated at room and cryogenic temperatures. Excessive noise, whose power was 25-50 times larger than that of room temperature, was observed at 20 K, and this hindered the accurate transfer of charge. Interestingly, the noise power was proportional to the square of the pulse frequency that drove the gates in these devices, and an expression for the noise was proposed to correlate it with the frequency, gate capacitance and fluctuation of the threshold voltage at the gate.
Źródło:
Journal of Automation Mobile Robotics and Intelligent Systems; 2009, 3, 4; 72-75
1897-8649
2080-2145
Pojawia się w:
Journal of Automation Mobile Robotics and Intelligent Systems
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Low Frequency Noise and Its Assessment and Evaluation
Autorzy:
Žiaran, S.
Powiązania:
https://bibliotekanauki.pl/articles/176925.pdf
Data publikacji:
2013
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
low frequency sound
human being
health
evaluation
Opis:
The main aim of this paper is to present recent knowledge about the assessment and evaluation of low frequency noise and infrasound close to the threshold of hearing and the potential effects on human health. Low frequency noise generated by air flowing over a moving car with the open window is chosen as a source of noise. The noise within the interior of the car and its effects on a driver’s comfort at different velocities is analyzed. An open window at high velocity behaves as a source of specifically strong tonal low frequency noise which is annoying. The interior noise of a passenger car was measured under different conditions; while driving on normal highway and roadways. First, an octave-band analysis was used to assess the noise level and its impact on the driver’s comfort. Second, a Fast Fourier Transform (FFT) analysis was used for the detection of tonal low frequency noise. Finally, the paper suggests possibilities for scientifically assessing and evaluating low frequency noise but not only for the presented source of the sound.
Źródło:
Archives of Acoustics; 2013, 38, 2; 265-270
0137-5075
Pojawia się w:
Archives of Acoustics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Brain’s Frequency Following Responses to Low-Frequency and Infrasound
Autorzy:
Jurado, Carlos
Marquardt, Torsten
Powiązania:
https://bibliotekanauki.pl/articles/176507.pdf
Data publikacji:
2020
Wydawca:
Polska Akademia Nauk. Czasopisma i Monografie PAN
Tematy:
low-frequency hearing
frequency-following response
infrasound
auditory brain
Opis:
Complaints and awareness about environmental low-frequency (LF) noise and infrasound (IS) have increased in recent years, but knowledge about perceptual mechanisms is limited. To evaluate the use of the brain’s frequency-following response (FFR) as an objective correlate of individual sensitivity to IS and LF, we recorded the FFR to monaurally presented IS (11 Hz) and LF (38 Hz) tones over a 30-phon range for 11 subjects. It was found that 11-Hz FFRs were often significant already at ~0 phon, steeply grew to 20 phon, and saturated above. In contrast, the 38-Hz FFR growth was relatively shallow and continued to 60 phon. Furthermore, at the same loudness level (30 phon), the 11-Hz FFR strength was significantly larger (4.5 dB) than for 38 Hz, possibly reflecting a higher phase synchronization across the auditory pathway. Overall, unexpected inter-individual variability as well as qualitative differences between the measured FFR growth functions and typical loudness growth make interpretation of the FFR as objective correlate of IS and LF sensitivity difficult.
Źródło:
Archives of Acoustics; 2020, 45, 2; 313-319
0137-5075
Pojawia się w:
Archives of Acoustics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Progress in stellarator research at IPP-Kharkov
Autorzy:
Moiseenko, V. E.
Lozin, O. V.
Shapoval, A. M.
Dreval, M. B.
Kulyk, Y. S.
Mironov, Y. K.
Romanov, V. S.
Pashnev, V. K.
Sorokovoy, E. L.
Petrushenya, A. A.
Ozherel’ev, F. I.
Kozulya, M. M.
Konovalov, V. G.
Maznichenko, S. M.
Garkusha, I. E.
Powiązania:
https://bibliotekanauki.pl/articles/146173.pdf
Data publikacji:
2016
Wydawca:
Instytut Chemii i Techniki Jądrowej
Tematy:
stellarator
radio-frequency heating
low frequency modes
magnetic diagnostics
Opis:
A new antenna of ‘crankshaft’ type has been installed in the Uragan-2M device in order to increase the plasma density and heating below the ion cyclotron frequency. Antenna operation is modelled by 1D code, which solves boundary problem for time-harmonic Maxwell’s equations in radially non-uniform plasma cylinder. In recent experiments with this antenna, the SXR, CV, OV and OII emission measurements indicate that the light impurity radiation barrier is overcame at this device. Plasma with a temperature of ~50 eV exists during a short period of a few milliseconds. Then the radiation collapse comes owing to strong infl ux of impurities to the plasma column. A new magnetic diagnostics has been installed at Uragan-3M. Using it the poloidal magnetic fi eld is measured and the shift of toroidal current in major radius is registered. A miniature pinhole camera array for spatially and temporally resolved measurements of soft X-ray (SXR) plasma emission has been recently installed on the U-3M. Different shapes of the SXR emission profi le has been observed in different discharge conditions.
Źródło:
Nukleonika; 2016, 61, 2; 91-97
0029-5922
1508-5791
Pojawia się w:
Nukleonika
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Efficiency of the constant interaction force vibroisolation (WoSSO)
Autorzy:
Dobry, M. W.
Powiązania:
https://bibliotekanauki.pl/articles/279381.pdf
Data publikacji:
2014
Wydawca:
Polskie Towarzystwo Mechaniki Teoretycznej i Stosowanej
Tematy:
low-frequency passive vibroisolation
efficiency of force vibroisolation
Opis:
In this paper, the force efficiency of the WoSSO vibroisolation in reducing forces transferred into the base by machines and the equipment working at low operating frequencies has been discussed. To assess that efficiency, a strongly non-linear mathematical model using Lagrange equations of the second kind has been developed. That model takes into account the specific design of the vibroisolator. The mathematical model has been solved using s digital simulation method, by developing a special computer program in the MATLAB/simulink environment. The efficiency of the force vibroisolation has been determined for a specific application of the WoSSO vibroisolator. The calculated force vibroisolation efficiency exceeds 32.
Źródło:
Journal of Theoretical and Applied Mechanics; 2014, 52, 4; 1083-1091
1429-2955
Pojawia się w:
Journal of Theoretical and Applied Mechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
On the Sound Radiation From a Circular Hatchway
Autorzy:
Arenas, J. P.
Powiązania:
https://bibliotekanauki.pl/articles/89797.pdf
Data publikacji:
2009
Wydawca:
Centralny Instytut Ochrony Pracy
Tematy:
low-frequency noise
sound radiation
circular plate
hatchway
Opis:
Low-frequency sound radiation from vibrating plates is a practical problem often found in engineering applications. In this article, the sound radiation from a circular hatchway is examined using a discrete approach based in the acoustic resistance matrix. Since this matrix can be combined with the volume velocity vector on the discretized vibrating circular surface, the sound radiation efficiency can be estimated through matrix approaches. The limitation of the approach is discussed by using benchmark results presented in previous works. The method produces acceptable results in low frequencies when the response of the plate is dominated by one low structural mode. When the response of more than one mode is significant, the method gives good estimation of the total sound power just for frequencies up to the first resonance. However, the method can be applied to complex and irregular vibrating plane surfaces.
Źródło:
International Journal of Occupational Safety and Ergonomics; 2009, 15, 4; 401-407
1080-3548
Pojawia się w:
International Journal of Occupational Safety and Ergonomics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The Modal Low Frequency Noise of an Elastically Supported Circular Plate
Autorzy:
Rdzanek, W. P.
Rdzanek, W. J.
Engel, Z.
Szemela, K.
Powiązania:
https://bibliotekanauki.pl/articles/89877.pdf
Data publikacji:
2007
Wydawca:
Centralny Instytut Ochrony Pracy
Tematy:
low frequency noise
radiation efficiency
circular plate
hatchway
Opis:
The modal low frequency noise generated by a vibrating elastically supported circular plate embedded into a flat infinite baffle has been examined. The main aim of this study is the analysis of the radiation efficiency. Low frequency approximated formulas have been presented. They are valid for all the limiting boundary conditions of the plate with its edge clamped, guided, simply supported or free as well as for all the intermediate axisymmetric boundary configurations. The formulas are expressed in the elementary form, useful for numerical computations. They are a generalization of some earlier published results. First, they are valid for axisymmetric and asymmetric modes since both kinds of modes play an important role in the low frequency range. Second, a single formula for the radiation efficiency, valid for all the axisymmetric boundary configurations, has been proposed. A numerical example for the sound power radiation has been given for some hatchway covers mounted on a ship deck.
Źródło:
International Journal of Occupational Safety and Ergonomics; 2007, 13, 2; 147-157
1080-3548
Pojawia się w:
International Journal of Occupational Safety and Ergonomics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Analysis and measure of novel stereo-garage driven by linear induction motor
Autorzy:
Lu, Q.
Ye, Y.
Shen, J.
Powiązania:
https://bibliotekanauki.pl/articles/140630.pdf
Data publikacji:
2015
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
FEM
linear induction motors
low frequency
stereo-garage
Opis:
The car access time is a key parameter, especially in a huge stereo-garage, where this one should be decreased as much as possible. This paper proposes a novel stereo-garage. Adopting the linear induction motors (LIMs), the system has a simple structure and rapid response capability. In the stereo-garage, several LIMs are installed below the crossbeam on a lifting platform, and several LIMs are fixed on the top of a moving frame. During the operation of LIMs, the moving frame moves forward and backward to reach the required parking place, whereas the crossbeam moves horizontally in order to take or store the vehicle rapidly. All these LIMs are the same and should be designed at a low frequency. The influences of key structure parameters and dynamic performances are investigated, based on FEM. The predicted results are validated by a prototype. Finally, the designed LIMs are successfully applied in two 8-layer stereo-garages.
Źródło:
Archives of Electrical Engineering; 2015, 64, 4; 669-678
1427-4221
2300-2506
Pojawia się w:
Archives of Electrical Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
An Observation of an Inverted Type U Solar Burst Due to AR1429 Active Region
Autorzy:
Hamidi, Z. S.
Shariff, N. N. M.
Monstein, C.
Powiązania:
https://bibliotekanauki.pl/articles/412209.pdf
Data publikacji:
2014
Wydawca:
Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
Tematy:
CALLISTO
low frequency
solar burst
type U
Radio Frequency Interference (RFI)
Opis:
A detailed investigation of an inverted type U solar burst in meter region and their associated the solar flare and Coronal Mass Ejections (CMEs) has been reported. Solar type U burst has been observed at the National Space Centre, Banting, Selangor detected by the Compound Low Cost Low Frequency Transportable Observatories (CALLISTO) system in the 150 MHz till 400 MHz at the low frequency band. An inverted U type is occurring on 9th March 2012 between 4:00 UT to 4:15 UT within 1 minute (4:12 − 4:13) UT. From the dynamic spectra of CALLISTO, we have identified metric type U burst with maximum emission near the frequency 385MHz. In specific, the continuum type III burst will soon structure this burst due to our observations. Other types such as type II and IV are only appearing only after type U burst is ejected and appear at the same point of the solar flare event. Since the U burst activity coincides with the peak of the hard X-ray flare at 4:12UT in AR1429, we classified that the event is associated with the injection of the high energetic particles. In conclusion, it is confirmed that an inverted type U burst is initiated after a complex and a group solar radio burst type III.
Źródło:
International Letters of Chemistry, Physics and Astronomy; 2014, 10; 81-90
2299-3843
Pojawia się w:
International Letters of Chemistry, Physics and Astronomy
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
ON LOW-FREQUENCY ESTIMATION OF BID-ASK SPREAD IN THE STOCK MARKET
Autorzy:
Kociński, Andrzej Marek
Powiązania:
https://bibliotekanauki.pl/articles/453684.pdf
Data publikacji:
2014
Wydawca:
Szkoła Główna Gospodarstwa Wiejskiego w Warszawie. Katedra Ekonometrii i Statystyki
Tematy:
high-frequency data
low-frequency data
Roll estimator
Corwin-Schultz estimator
Opis:
In the article two popular low-frequency methods od bid-ask spread estimation are presented and applied to the stocks quoted on the Warsaw Stock Exchange (WSE): the Roll method [Roll 1984] and Corwin-Schultz method [Corwin and Schultz 2012]. The widely available data on average spreads published by WSE are used as benchmark and proxy of information, usually received from difficult to access and limited high-frequency financial data
Źródło:
Metody Ilościowe w Badaniach Ekonomicznych; 2014, 15, 2; 135-143
2082-792X
Pojawia się w:
Metody Ilościowe w Badaniach Ekonomicznych
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Comparison of the Radio Frequency Interference (RFI) in the Region of Solar Burst Type III Data At Selected CALLISTO Network
Autorzy:
Hamidi, Z. S.
Shariff, N. N. M.
Monstein, C.
Powiązania:
https://bibliotekanauki.pl/articles/412319.pdf
Data publikacji:
2014
Wydawca:
Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
Tematy:
CALLISTO
low frequency
solar burst type III
Radio Frequency Interference (RFI)
Opis:
Compact Astronomical Low-frequency, Low-cost Instrument for Spectroscopy in Transportable Observatories (CALLISTO) is a global network of spectrometer system with the purpose to observe the Sun’s activities. There are 25 stations that are used for this purpose. Radio Frequency Interference (RFI) is a major obstacle when performing observation with CALLISTO. We have confirmed at least 2 stations out of 10 stations with a complete overview spectral (OVS) made available to us showed clear detection of these consistent types of RFI for each specific region. In Malaysia, these RFI are also clearly detected. The major RFI affecting CALLISTO within radio astronomical windows below 1 GHz are local electronic system specifically radio navigation (at 73.1 MHz and 75.2 MHz), broadcasting (at (i) 151 MHz, (ii) 151.8 MHz and 152 MHz), aeronautical navigation (at (i) 245.5 MHz, (ii) 248.7 MHz and (iii) 249 MHz and fixed mobile at (i) 605 MHz, (ii) 608.3 MHz, (iii) 612.2 MHz, (iv) 613.3 MHz). It is obviously showed that all sites within this region are free from interference at 320-330 MHz and is the best specific region to be considered for solar burst monitoring. We also investigate the effect of RFI on detection of solar burst. We have considered type III solar bursts on 9th March 2012 in order to measure the percentage of RFI level during the solar burst. The RFI level is as low as 6.512 % to 80.769 % above solar burst detection.
Źródło:
International Letters of Chemistry, Physics and Astronomy; 2014, 10; 38-45
2299-3843
Pojawia się w:
International Letters of Chemistry, Physics and Astronomy
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Electrical Characterization of 65 W Cubic Sonoreactor with Horizontally Stacked Transducers
Autorzy:
Kerdthongmee, P.
Pholnak, C.
Sirisathitkul, C.
Danworaphong, S.
Powiązania:
https://bibliotekanauki.pl/articles/176328.pdf
Data publikacji:
2017
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
sonoreactor
dual stack transducer
low frequency ultrasound
RLC circuit
resonant frequency
Opis:
A sonoreactor was assembled with stacked lead zirconate titanate transducers. These transducers were attached on one side of a 10×10×10 cm3 chamber and driven by an integrated circuit power amplifier. The impedance of the reactor was analyzed in order to determine a matching inductance. The electrical frequency could be varied from 20 to 50 kHz and the electrical output power was adjustable up to 65 W. The highest power was obtained in the case of resonance at 31 kHz and the maximum temperature at the heat sink of the amplifier rose to 42.0ºC. Both acoustic cavitation and mechanical effects could be utilized in this sonoreactor for a variety of purposes including sonochemical synthesis, ultrasonic cleaning and microbial cell disruption.
Źródło:
Archives of Acoustics; 2017, 42, 1; 149-153
0137-5075
Pojawia się w:
Archives of Acoustics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Wpływ drgań niskoczęstotliwościowych na wybrane parametry fizjologiczne
Changes of selected physiological parameters under low frequency vibration
Autorzy:
Damijan, Z.
Powiązania:
https://bibliotekanauki.pl/articles/328276.pdf
Data publikacji:
2005
Wydawca:
Polska Akademia Nauk. Polskie Towarzystwo Diagnostyki Technicznej PAN
Tematy:
drgania niskoczęstotliwościowe
parametry fizjologiczne
low frequency vibration
physiological parameters
Opis:
Praca przedstawia badania i analizy wpływu drgań niskoczęstotliwościowych na wybrane parametry fizjologiczne organizmu człowieka. Z uwagi na nieliczne doniesienia literaturowe o możliwości stosowania drgań niskoczęstotliwościowych w terapii, przeprowadzono badania mające na celu sprawdzenie jak ekspozycja drganiami wpływa na zmiany wytypowanych parametrów fizjologicznych.
The aim of the work was the re-search and analysis con-cerning the influence of low-fre-quency vibra-tions on chosen func-tional parame-ters of human body. Due to the fact, that there is not much literature on the possibility of using low-fre-quency vibrations in therapy. The experi-ment carried what are the changes of chosen physiologi-cal parameters.
Źródło:
Diagnostyka; 2005, 35; 101-104
1641-6414
2449-5220
Pojawia się w:
Diagnostyka
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Modern Methods of Irrigation Water Purification by a Mesh-Filter Using Influence of Low Frequency Vibration
Autorzy:
Bilokon, S.
Turbal, Y.
Kunanets, N.
Pasichnyk, V.
Powiązania:
https://bibliotekanauki.pl/articles/410930.pdf
Data publikacji:
2019
Wydawca:
Polska Akademia Nauk. Oddział w Lublinie PAN
Tematy:
irrigation water
low-frequency vibration
standing wave
floating impurities
Opis:
The article is devoted to the analysis of different methods of irrigation water purification from suspended particles. There have been considered the problems of irrigation water purification by using the low-frequency vibration technology and the effects arising from the influence of vibration on the water with different floating impurities. Vibration parameters that allow obtaining the effect of standing wave was substantiated. Also in the article have been disclosed the influence of low-frequency vibration on the quality of water purification depending on the types of pollution and their granulometric composition. Obtained the hydraulic characteristics of the mesh such as the effect of vibration on the pressure loss.
Źródło:
ECONTECHMOD : An International Quarterly Journal on Economics of Technology and Modelling Processes; 2019, 8, 2; 21-26
2084-5715
Pojawia się w:
ECONTECHMOD : An International Quarterly Journal on Economics of Technology and Modelling Processes
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Influence of Low-Frequency Ultrasound on the Disintegration of Coliform and Fecal Coliform Bacteria
Autorzy:
Hawrylik, Eliza
Butarewicz, Andrzej
Powiązania:
https://bibliotekanauki.pl/articles/1955566.pdf
Data publikacji:
2021
Wydawca:
Polskie Towarzystwo Inżynierii Ekologicznej
Tematy:
coliform bacteria
ultrasonic disintegration
low frequency ultrasound
treated wastewater
Opis:
Wastewater contains an abundance of pathogenic microorganisms, which, if they infiltrate into the environment, can cause many bacterial diseases. The lack of widespread use of the wastewater disinfection process raises more and more concerns about the sanitary quality of the wastewater leaving treatment plants. This article aimed to test the effectiveness of the ultrasonic disintegration process against coliform bacteria and fecal coliforms in the treated wastewater. The paper presents the research on the use of ultrasound with a frequency of 20 and 40 kHz, with a variable and constant operating mode of an ultrasonic cleaner. The obtained test results confirm the effectiveness of the applied method. In most of the analyzed cases, 25-minute sonication reduced the number of tested microorganisms by over 90% compared to the control sample. Ultrasonic disintegration can therefore be successfully used in municipal wastewater treatment plants. The use of ultrasound for disinfection can improve the sanitary safety of the wastewater discharged into water or soil.
Źródło:
Journal of Ecological Engineering; 2021, 22, 9; 192-197
2299-8993
Pojawia się w:
Journal of Ecological Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Low frequency noise in advanced Si bulk and SOI MOSFETs
Autorzy:
Jomaah, J.
Balestra, F.
Ghibaudo, G.
Powiązania:
https://bibliotekanauki.pl/articles/308980.pdf
Data publikacji:
2005
Wydawca:
Instytut Łączności - Państwowy Instytut Badawczy
Tematy:
CMOS
SOI
low frequency noise
kink-related excess noise
DTMOS
Opis:
A review of recent results concerning the low frequency noise in modern CMOS devices is given. The approaches such as the carrier number and the Hooge mobility fluctuations used for the analysis of the noise sources are presented and illustrated through experimental data obtained on advanced CMOS SOI and Si bulk generations. Furthermore, the impact on the electrical noise of the shrinking of CMOS devices in the deep submicron range is also shown. The main physical characteristics of random telegraph signals (RTS) observed in small area MOS transistors are reviewed. Experimental results obtained on 0.35-0.12 žm CMOS technologies are used to predict the trends for the noise in future CMOS technologies, e.g., 0.1 žm and beyond. For SOI MOSFETS, the main types of layout will be considered, that is floating body, DTMOS, and body-contact. Particular attention will be paid to the floating body effect that induces a kink-related excess noise, which superimposes a Lorentzian spectrum on the flicker noise.
Źródło:
Journal of Telecommunications and Information Technology; 2005, 1; 24-33
1509-4553
1899-8852
Pojawia się w:
Journal of Telecommunications and Information Technology
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Type II Solar Radio Burst with a Split and Herring − Bones During a Minimum Solar Activity
Autorzy:
Hamidi, Z. S.
Shariff, N. N. M.
Monstein, C.
Powiązania:
https://bibliotekanauki.pl/articles/411839.pdf
Data publikacji:
2014
Wydawca:
Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
Tematy:
sun
low frequency
solar radio
burst
type II
e-CALLISTO
Opis:
A preliminary correlation study of the herring − bone type II with a type III solar burst of has been made. On the basis of this study and in combination with the observation in radio emission, an interpretation of the mechanism of the occurrence of this event has been proposed. The type II solar radio burst with a split and herring bone is occurring at the same time from 36 MHz till 50 MHz. We have noted that an individual type III burst also can be observed at 13:23 UT from 45-50 MHz. During that day, a stream of solar wind from a coronal hole on the Sun has disturbing Earth's magnetosphere creating a minor geomagnetic storm, G1 on the NOAA scale of G1-G5. In this case, the solar flare is not very high, but CME is responsible to form a solar radio burst type II. Overall, based on seven days observation beginning from 25th March 2013, the solar activity is considered as very low. The highest solar flare can be observed within 7 days is only a class of B8 flare. There was no CMEs event that directed to the Earth is detected. The geomagnetic field activities are also at minimum level. Although the solar flare event is at a lower stage, it is still possible to form the solar radio burst type II which is associated with CME event. From the selected event, although theoretically solar radio burst type II is associated with CMEs, there is no compelling solar radio burst type II without a flare. The only difference is the dynamic structure and the intensity and speed of both phenomena (solar flares and CMEs) which depend on the active region. Nevertheless, understanding how energy is released in solar flares is one of the central questions in astrophysics. This solar radio burst type II formation is the first event that successfully detected by e-CALLISTO network in 2013.
Źródło:
International Letters of Chemistry, Physics and Astronomy; 2014, 13, 2; 104-111
2299-3843
Pojawia się w:
International Letters of Chemistry, Physics and Astronomy
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Noise Properties of Graphene-Polymer Thick-Film Resistors
Autorzy:
Mleczko, K.
Ptak, P.
Zawiślak, Z.
Słoma, M.
Jakubowska, M.
Kolek, A.
Powiązania:
https://bibliotekanauki.pl/articles/220754.pdf
Data publikacji:
2017
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
graphene
polymer thick-film resistor
low-frequency noise
noise measurements
Opis:
Graphene is a very promising material for potential applications in many fields. Since manufacturing technologies of graphene are still at the developing stage, low-frequency noise measurements as a tool for evaluating their quality is proposed. In this work, noise properties of polymer thick-film resistors with graphene nano-platelets as a functional phase are reported. The measurements were carried out in room temperature. 1/f noise caused by resistance fluctuations has been found to be the main component in the specimens. The parameter values describing noise intensity of the polymer thick-film specimens have been calculated and compared with the values obtained for other thick-film resistors and layers used in microelectronics. The studied polymer thick-film specimens exhibit rather poor noise properties, especially for the layers with a low content of the functional phase.
Źródło:
Metrology and Measurement Systems; 2017, 24, 4; 589-594
0860-8229
Pojawia się w:
Metrology and Measurement Systems
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Noise Properties Of Thick-Film Conducting Lines For Integrated Inductors
Autorzy:
Stadler, A. W.
Kolek, A.
Mleczko, K.
Zawiślak, Z.
Dziedzic, A.
Nowak, D.
Powiązania:
https://bibliotekanauki.pl/articles/221399.pdf
Data publikacji:
2015
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
low-frequency noise
thick-film conducting layer
thick-film inductor
Opis:
Studies of noise properties of thick-film conducting lines from Au or PdAg conductive pastes on LTCC or alumina substrates are reported. Experiments have been carried out at the room temperature on samples prepared in the form of meanders by traditional screen-printing or laser-shaping technique. Due to a low resistance of the devices under test (DUTs), low-frequency noise spectra have been measured for the dc-biased samples arranged in a bridge configuration, transformer-coupled to a low-noise amplifier. The detailed analysis of noise sources in the signal path and its transfer function, including the transformer, has been carried out, and a procedure for measurement setup self-calibration has been described. The 1/f noise component originating from resistance fluctuations has been found to be dominant in all DUTs. The analysis of experimental data leads to the conclusion that noise is produced in the bends of meanders rather than in their straight segments. It occurs that noise of Au-based laser-shaped lines is significantly smaller than screen-printed ones. PdAg lines have been found more resistive but simultaneously less noisy than Au-based lines.
Źródło:
Metrology and Measurement Systems; 2015, 22, 2; 229-240
0860-8229
Pojawia się w:
Metrology and Measurement Systems
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Wpływ drgań wibracyjnych o niskiej częstotliwości na wybrane parametry fizjologiczne sportowców
The effect of low frequency vibration on selected physiological parameters in athletes
Autorzy:
Pośpiech, S.
Czapkowicz-Pośpiech, R.
Barucha, P.
Błaszczyk, J.
Powiązania:
https://bibliotekanauki.pl/articles/99293.pdf
Data publikacji:
2016
Wydawca:
Politechnika Śląska. Katedra Biomechatroniki
Tematy:
drgania wibracyjne niskoczęstotliwościowe
parametry fizjologiczne
low frequency vibration
physiological parameters
Opis:
Praca przedstawia wpływ krótkotrwałych drgań ogólnych o częstotliwości 3.5 Hz na wybrane parametry fizjologiczne sportowców. W badaniu zastosowano platformę wibracyjną generującą drgania harmoniczne o częstotliwości biegu człowieka-3.5 Hz i wzrastającej amplitudzie od 4 do 5,5 mm. W pracy założono, że stanie na platformie w pozycji swobodnej bez wykonywania żadnych dodatkowych ćwiczeń stanowi dla organizmu człowieka trening fizyczny oraz że platforma wibracyjna jest urządzeniem, które odtwarza bodźce mechaniczne występujące w czasie biegu lub szybkiego marszu.
The study is focused on the effect of a short-term general 3.5 Hz frequency vibration on physiological parameters in athletes. The study used a vibration platform designed for the requirements of the experiment, generating harmonic vibration with the frequency of a human run-3.5 Hz, and the amplitude increased from 4 to 5 millimeters. The study assumed that free standing on the platform with no other physical exercises is an exercise for the human organism and that a vibration platform is a device that reproduces mechanical stimuli associated with running or a vigorous march.
Źródło:
Aktualne Problemy Biomechaniki; 2016, 10; 49-56
1898-763X
Pojawia się w:
Aktualne Problemy Biomechaniki
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Four-point probe resistivity noise measurements of GaSb layers
Autorzy:
Ciura, L.
Kolek, A.
Smoczyński, D.
Jasik, A.
Powiązania:
https://bibliotekanauki.pl/articles/201503.pdf
Data publikacji:
2020
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
low frequency noise
GaSb noise
noise measurements
resistance noise calculation
Opis:
This paper concerns measurements and calculations of low frequency noise for semiconductor layers with four-probe electrodes. The measurements setup for the voltage noise cross-correlation method is described. The gain calculations for local resistance noise are performed to evaluate the contribution to total noise from different areas of the layer. It was shown, through numerical calculations and noise measurements, that in four-point probe specimens, with separated current and voltage terminals, the non-resistance noise of the contact and the resistance noise of the layer can be identified. The four-point probe method is used to find the low frequency resistance noise of the GaSb layer with a different doping type. For n-type and p-type GaSb layers with low carrier concentrations, the measured noise is dominated by the non-resistance noise contributions from contacts. Low frequency resistance noise was identified in high-doped GaSb layers (both types). At room temperature, such resistance noise in an n-type GaSb layer is significantly larger than for p-type GaSb with comparable doping concentration.
Źródło:
Bulletin of the Polish Academy of Sciences. Technical Sciences; 2020, 68, 1; 135-140
0239-7528
Pojawia się w:
Bulletin of the Polish Academy of Sciences. Technical Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Badanie wpływu dźwięków niskiej częstotliwości na poziom aktywności elektrodermalnej
The effects of low-frequency sound exposure on the level of electrodermal activity
Autorzy:
Damijan, Z.
Powiązania:
https://bibliotekanauki.pl/articles/328274.pdf
Data publikacji:
2005
Wydawca:
Polska Akademia Nauk. Polskie Towarzystwo Diagnostyki Technicznej PAN
Tematy:
dźwięki niskoczęstotliwościowe
aktywność elektrodermalna (EDA)
low frequency sound
electrodermal activity
Opis:
Praca przedstawia badania wpływu dźwięków niskiej częstotliwości na poziom aktywności elektrodermalnej skóry (ozn. EDA). Badania stanowiły trzy niezależne sytuacje badawcze, pierw-sza: dla częstotliwości bodźca fśr=7 Hz przy poziomie ciśnienia akustycznego Lp = 120 dB HP, druga - (fśr=18 Hz, Lp = 120 dB HP) oraz trzecia - (fśr=40 Hz, Lp = 110 dB HP). Każdy, 35 minu-towy, ekspe-ryment składał się z trzech etapów. Etap I - 5 minutowy - bez ekspozycji bodźca. Etap II z 20 mi-nutowa ekspozycją na uczestników bodźca dźwiękowego niskiej częstotliwości. Trzeci etap 10 minutowy bez ekspozycji bodźca. W każdym eksperymencie w sposób ciągły rejestro-wano wyty-powane parametry EDA.
The paper investigates the effects of low-frequency sound exposure on the level of elec-trodermal activity (EDA). The experimental programme involved three independent tests 1st ex-periment: frequency fśr = 7 Hz, acoustic pressure Lp = 120 dB HP, 2nd experiment - (fśr = 18 Hz, Lp = 120 dB HP), 3rd experiment - (fśr = 40 Hz, Lp = 110 dB HP). Each 35 minutes' long session involved three stages. During the first stage, lasting 1 -5 minutes, there was no low-frequency sound exposure. During the second stage participants were exposed to low-frequency sound for 20 min. The third stage did not involve any low-frequency sound exposure. During each experiment selected EDA parameters were monitored on an online basis.
Źródło:
Diagnostyka; 2005, 35; 95-100
1641-6414
2449-5220
Pojawia się w:
Diagnostyka
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Study on Chinese Speech Intelligibility Under Different Low-Frequency Characteristics of Reverberation Time Using a Hybrid Method
Autorzy:
Huang, Wuqiong
Peng, Jianxin
Xie, Tinghui
Powiązania:
https://bibliotekanauki.pl/articles/31339871.pdf
Data publikacji:
2023
Wydawca:
Polska Akademia Nauk. Czasopisma i Monografie PAN
Tematy:
low frequency
speech intelligibility
classroom
finite-difference time-domain method
Opis:
Reverberation time (RT) is an important indicator of room acoustics, however, most studies focus on the mid-high frequency RT, and less on the low-frequency RT. In this paper, a hybrid approach based on geometric and wave methods was proposed to build a more accurate and wide frequency-band room acoustic impulse response. This hybrid method utilized the finite-difference time-domain (FDTD) method modeling at low frequencies and the Odeon simulation at mid-high frequencies, which was investigated in a university classroom. The influence of the low-frequency RT on speech intelligibility was explored. For the low-frequency part, different impedance boundary conditions were employed and the effectiveness of the hybrid method has also been verified. From the results of objective acoustical parameters and subjective listening experiments, the smaller the low-frequency RT was, the higher the Chinese speech intelligibility score was. The syllables, consonants, vowels, and the syllable order also had significant effects on the intelligibility score.
Źródło:
Archives of Acoustics; 2023, 48, 3; 151-157
0137-5075
Pojawia się w:
Archives of Acoustics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Katalog przemysłowych zabezpieczeń przed hałasem infradźwiękowym i niskoczęstotliwościowym
Catalogue of noise control measures in low frequency range
Autorzy:
Kaczmarska, A.
Augustyńska, D.
Engel, Z.
Powiązania:
https://bibliotekanauki.pl/articles/181243.pdf
Data publikacji:
2002
Wydawca:
Centralny Instytut Ochrony Pracy
Tematy:
hałas
hałas infradźwiękowy
hałas niskoczęstotliwościowy
noise
infrasound noise
low frequency noise
Opis:
Artykuł przedstawia katalog wybranych przemysłowych zabezpieczeń przed hałasem infradźwiękowym i niskoczęstotliwościowym. Przedstawiono parametry akustyczne materiałów, wyrobów i elementów stosowanych do ochrony przed hałasem niskoczęstotliwościowym.
This paper shall be presented catalogue of industrial noise control measures in low frequency range. Acoustic properties of the materials, goods and structures designed to protect from low frequency noise have bean determined in this paper.
Źródło:
Bezpieczeństwo Pracy : nauka i praktyka; 2002, 6; 24-25
0137-7043
Pojawia się w:
Bezpieczeństwo Pracy : nauka i praktyka
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Study and Assessment of Low Frequency Noise in Occupational Settings
Autorzy:
Shehap, A. M.
Shawky, H. A.
El-Basheer, T. M.
Powiązania:
https://bibliotekanauki.pl/articles/177844.pdf
Data publikacji:
2016
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
low frequency noise
A-weighting
C-weighting
audible
method of assessment
Opis:
Low frequency noise is one of the most harmful factors occurring in human working and living environment. Low frequency noise components from 20 to 250 Hz are often the cause of employee complaints. Noise from power stations is an actual problem for large cities, including Cairo. The noise from equipments of station could be a serious problem for station and for environmental area. The development of power stations in Cairo leads to appearing a wide range of gas turbines which are strong source of noise. Two measurement techniques using C-weighted along side the A-weighted scale are explored. C-weighting is far more sensitive to detect low frequency sound. Spectrum analysis in the low frequency range is done in order to identify a significant tonal component. Field studies were supported by a questionnaire to determine whether sociological or other factors might influence the results by using annoyance rating mean value. Subjects included in the study were 153 (mean = 36.86, SD = 8.49) male employees at the three electrical power stations. The (C-A) level difference is an appropriate metric for indicating a potential low frequency noise problem. A-weighting characteristics seem to be able to predict quite accurately annoyance experienced from LFN at workplaces. The aim of the present study is to find simple and reliable method for assessing low frequency noise in occupational environment to prevent its effects on work performance for the workers. The proposed method has to be compared with European methods.
Źródło:
Archives of Acoustics; 2016, 41, 1; 151-160
0137-5075
Pojawia się w:
Archives of Acoustics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Acoustic Study of REpower MM92 Wind Turbines During Exploitation
Autorzy:
Kłaczyński, M.
Wszołek, T.
Powiązania:
https://bibliotekanauki.pl/articles/177881.pdf
Data publikacji:
2014
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
wind turbine noise
low frequency noise
airfoil self noise
measurements assessment
Opis:
The paper presents the current state of knowledge concerning the sources of noise generated by wind turbines, force measurement methodology, and assessment of noise onerousness in this type of installation, on the basis of a study concerning a wind farm with five REpower MM92 wind turbines and the electric power of 2 MW and the sound power level of 104.2 dB(A) each. Particular attention was focused on the often discussed problem of presence of infrasound generated by turbines and on the requirements of the applicable reference methodologies for the measurement of wind speed to 5 m/s, while the turbine reaches its full power at speeds above 10 m/s.
Źródło:
Archives of Acoustics; 2014, 39, 1; 3-10
0137-5075
Pojawia się w:
Archives of Acoustics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Badania i ocena uciążliwości hałasu niskoczęstotliwościowego w czterokondygnacyjnym budynku mieszkalnym
Investigations and analysis of low frequnecy troublesome in a fourstorey living house
Autorzy:
Wiciak, J.
Powiązania:
https://bibliotekanauki.pl/articles/328113.pdf
Data publikacji:
2005
Wydawca:
Polska Akademia Nauk. Polskie Towarzystwo Diagnostyki Technicznej PAN
Tematy:
fale niskoczęstotliwościowe
identyfikacja źródeł hałasu
low frequency waves
noise source identification
Opis:
W pracy przedstawiono badania i ocenę hałasu niskoczęstotliwościowego występującego w wybranym czterokondygnacyjnym budynku mieszkalnym. Ocenę warunków akustycznych występujących w badanym budynku przeprowadzono w oparciu o Instrukcję ITB 358/98.
The paper presents results and analysis of investigations of low frequency noise sources, existing in living houses. The results of noise measurements in building were carried out according to instruction ITB 358/98.
Źródło:
Diagnostyka; 2005, 36; 109-116
1641-6414
2449-5220
Pojawia się w:
Diagnostyka
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
On the design of an automated system for the characterization of the electromigration performance of advanced interconnects by means of low-frequency noise measurements
Autorzy:
Scandurra, Graziella
Beyne, Sofie
Giusi, Gino
Ciofi, Carmine
Powiązania:
https://bibliotekanauki.pl/articles/221721.pdf
Data publikacji:
2019
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
low-frequency noise measurements
electron devices reliability
electro-migration
dedicated instrumentation
Opis:
Low-frequency noise measurements have long been recognized as a valuable tool in the examination of quality and reliability of metallic interconnections in the microelectronic industry. While characterized by very high sensitivity, low-frequency noise measurements can be extremely time-consuming, especially when tests have to be carried out over an extended temperature range and with high temperature resolutionas it is required by some advanced characterization approaches recently proposed in the literature. In order to address this issue we designed a dedicated system for the characterization of the low-frequency noise produced by a metallic line vs temperature. The system combines high flexibility and automation with excellent background noise levels. Test temperatures range from ambient temperature up to 300°C. Measurements can be completely automated with temperature changing in pre-programmed steps. A ramp temperature mode is also possible that can be used, with proper caution, to virtually obtain a continuous plot of noise parameters vs temperature.
Źródło:
Metrology and Measurement Systems; 2019, 26, 1; 13-21
0860-8229
Pojawia się w:
Metrology and Measurement Systems
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Hałas niskoczęstotliwościowy w samochodach osobowych
Low frequency noise in passenger cars
Autorzy:
Zagubień, A.
Wolniewicz, W.
Powiązania:
https://bibliotekanauki.pl/articles/312948.pdf
Data publikacji:
2017
Wydawca:
Instytut Naukowo-Wydawniczy "SPATIUM"
Tematy:
hałas niskoczęstotliwościowy
infradźwięki
pomiary hałasu
low frequency noise
infrasound
noise measurement
Opis:
W artykule przedstawiono analizę hałasu niskoczęstotliwościowego w wybranych modelach samochodów osobowych. Badania prowadzono w dwóch wariantach: przejazd z zamkniętymi wszystkimi oknami oraz przejazd z uchylonym szyberdachem. Pojazdy poruszały się po autostradzie z dużymi prędkościami. Autorzy nie dokonują oceny zarejestrowanych wyników badań, wskazują jedynie na wysokie poziomy hałasu infradźwiękowego i niskoczęstotliwościowego w pojazdach osobowych poruszających się z prędkościami autostradowymi.
The article presents an analysis of low frequency noise in selected models of passenger cars. The study has been performed in two variants: travel with all windows closed and travel with the sliding roof half-open. The vehicles moved along the motorway with high speeds. The authors do not evaluate the recorded study results, but only indicate the high levels of infrasound and low frequency noise in passenger cars moving at motorway speeds.
Źródło:
Autobusy : technika, eksploatacja, systemy transportowe; 2017, 18, 7-8; 139-142
1509-5878
2450-7725
Pojawia się w:
Autobusy : technika, eksploatacja, systemy transportowe
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
First Light Detection of A Single Solar Radio Burst Type III Due To Solar Flare Event
Autorzy:
Hamidi, Z. S.
Shariff, N. N. M.
Monstein, C.
Powiązania:
https://bibliotekanauki.pl/articles/411677.pdf
Data publikacji:
2014
Wydawca:
Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
Tematy:
Solar flare
low frequency
radio wavelength
solar burst
type III
CALLISTO
Opis:
The eruption mechanism of solar flares and type III are currently an extremely active area of research, especially during the solar cycle is towards maximum. In this case, the total energy of solar burst type III is of the order of solar flare with the explosion of the energy can up to 1015 ergs. The solar flare event is one of the most spectacular explosions that still be on-going study in the solar physics world. This event occurred at 2:000 UT on 15th April 2012 is due to the explosion of the magnetic energy in from the chromosphere and converted into the heating, mass motion and particle acceleration which can be detected by solar radio burst type III. In this work, we will highlight our first light detection of very tiny solar radio burst type III, which has been observed at the National Space Centre, Banting, Selangor detected by the Compound Low Cost Low Frequency Transportable Observatories (CALLISTO) system at 5:53:23. The region of the data is from 150 − 400 MHz in radio region. This burst is drifted from 150 MHz till 260 MHz. It represents a total energy of 6.2035 × 10-7 eV − 1.0753 × 10-6 eV. This fast drift burst is a continuity of the acceleration of the particles which is intermittent, and can be observed since the explosion of the solar flare. Although the burst is very tiny, it is still significant because this burst is the first detection of a single type III burst from our site. Still, the acceleration of the particles can be detected from Earth in the radio region within 3 hours period of observation at the post stage of solar flare.
Źródło:
International Letters of Chemistry, Physics and Astronomy; 2014, 11, 1; 51-58
2299-3843
Pojawia się w:
International Letters of Chemistry, Physics and Astronomy
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Badania wpływu nadmiernej ekspozycji na hałas niskoczęstotliwościowy - choroba wibroakustyczna
Effects of exposure to low - frequency noise - the vibroacoustic disease
Autorzy:
Engel, Z.
Kaczmarska, A.
Augustyńska, D.
Powiązania:
https://bibliotekanauki.pl/articles/180627.pdf
Data publikacji:
2005
Wydawca:
Centralny Instytut Ochrony Pracy
Tematy:
hałas niskoczęstotliwościowy
wibroakustyka
choroba wibroakustyczna
low-frequency noise
vibroacoustic
vibroacoustic disease
Opis:
W artykule omówiono takie pojęcia, jak wibroakustyczna terapia i choroba wibroakustyczna, która może być następstwem długotrwałej, znaczącej ekspozycji na hałas niskoczęstotliwościowy i infradźwięki. Przedstawiono kierunki aktualnych badań prowadzonych w Centralnym Instytucie Ochrony Pracy - Państwowym Instytucie Badawczym w zakresie uciążliwości dźwięków o niskich częstotliwościach.
This article discuses terms such as vibroacoustic therapy and vibroacoustic disease. The vibroacoustic disease is inducted by long-term exposure to low-frequency noise and infrasound. The results of tests on the annoyance of low-frequency sounds carried out by the Central Labour Protection – National Research Institute are also presented.
Źródło:
Bezpieczeństwo Pracy : nauka i praktyka; 2005, 11; 4-7
0137-7043
Pojawia się w:
Bezpieczeństwo Pracy : nauka i praktyka
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
TDR and low-frequency measurements for continuous monitoring of moisture and density in a snow pack
Autorzy:
Stacheder, M.
Powiązania:
https://bibliotekanauki.pl/articles/25546.pdf
Data publikacji:
2005
Wydawca:
Polska Akademia Nauk. Instytut Agrofizyki PAN
Tematy:
moisture
low-frequency measurement
monitoring
time domain reflectometry
density
snow density
Źródło:
International Agrophysics; 2005, 19, 1
0236-8722
Pojawia się w:
International Agrophysics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Biological risk assessment of high-voltage transmission lines on worker’s health of electric society
Autorzy:
Bidi, Manel
Powiązania:
https://bibliotekanauki.pl/articles/141717.pdf
Data publikacji:
2020
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
biological risk
electromagnetic fields
extremely low frequency
induced current
overhead lines
Opis:
A probable risk for different diseases has been reported due to exposure of peoples living in the vicinity of electrical substations and electrical workers. The aim of this paper is to examine and reduce the induced current density due to the power system field acting on human beings in the working environment, by using the spheroidal calculation model. The results obtained by means of computer programs developed by the author in the MATLAB environment are compared with the limit values given by the International Committee on Non-Ionizing Radiation Protection (ICNIRP) for demonstrating the degree of danger due to the induced current and have a certain guidance function for worker’s health to ensure their safety
Źródło:
Archives of Electrical Engineering; 2020, 69, 1; 57-68
1427-4221
2300-2506
Pojawia się w:
Archives of Electrical Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Pomiary charakterystyk szumowych jako narzędzie diagnostyczne detektorów UV
Noise characteristic measurement as a tool for UV detectors diagnostic
Autorzy:
Ćwirko, J.
Ćwirko, R.
Powiązania:
https://bibliotekanauki.pl/articles/327504.pdf
Data publikacji:
2006
Wydawca:
Polska Akademia Nauk. Polskie Towarzystwo Diagnostyki Technicznej PAN
Tematy:
detektor UV
GaN
AlGaN
szumy niskoczęstotliwościowe
UV detectors
low-frequency noise
Opis:
W artykule przedstawiono zastosowanie analizy niskoczęstotliwościowych charakterystyk szumowych do diagnostyki detektorów UV. Ze względu na zakres widmowy detektory UV są wykonywane z materiałów o szerokiej przerwie zabronionej, głównie z GaN, AlN, SiC. Detektory UV są głównie stosowane w automatyce przemysłowej, robotyce, medycynie, systemach ochrony środowiska i technologiach militarnych. Charakterystyki szumowe detektorów były mierzone w szerokim zakresie temperatury (80 K - 350 K) oraz w funkcji napięcia polaryzacji. Analiza charakterystyk szumowych umożliwia wybranie optymalnego punktu pracy detektora ze względu na stosunek sygnału użytecznego do szumu oraz pozwala prognozować jego niezawodność.
The work is aimed on analyze the low frequency noise characteristics of UV detectors. UV detectors are manufactured from wide band gap materials as GaN, AlGaN, SiC. The most important fields of UV detectors applications are industrial automation, robotics, space technology, medicine, military technology and solar ultraviolet measurements. The noise characteristics of UV detectors were measurement in wide temperature range (from 80 K to 350 K) and as function of polarization. The investigation results should be allowed to optimize the UV detection system providing maximal value of signal-to-noise ratio, selection of the optimal working point and estimate reliability of detectors UV.
Źródło:
Diagnostyka; 2006, 4(40); 199-202
1641-6414
2449-5220
Pojawia się w:
Diagnostyka
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Badanie wpływu niskoczęstotliwościowego pola magnetycznego (f=7 Hz, B=330 nT) na wybrane parametry elektrofizjologiczne organizmu
The effects of low-frequency magnetic field (f =7 Hz, B=330 nT) exposure on selected physiological parameters of human body
Autorzy:
Damijan, Z.
Powiązania:
https://bibliotekanauki.pl/articles/328539.pdf
Data publikacji:
2007
Wydawca:
Polska Akademia Nauk. Polskie Towarzystwo Diagnostyki Technicznej PAN
Tematy:
niskoczęstotliwościowe pole magnetyczne
czynność bioelektryczna
low-frequency magnetic filed
bioelectric activity
Opis:
W wykonanych przez autora badaniach nt. wpływu infradźwięków na organizm człowieka prowadzonych w kabinie ciśnieniowej typu węgierskiego, bodziec generowano za pomocą głośników elektrodynamicznych GDN 30/80, oprócz ekspozycji dźwięku, czynnikiem zakłócającym było pole elektromagnetyczne (PEM). Pole elektryczne eliminowano przez zastosowanie siatki Faradaya. Czynnikiem zakłócającym pozostawało zmienne pole magnetyczne (PM) głośników (f=7 Hz, B=330 nT). Autor postawił tezę, że PM niskiej częstotliwości może wpływać na organizm człowieka. Jako estymaty wpływu ekspozycji PM zaproponowano wariancję oraz wartość skuteczną sygnału EEG. W eksperymencie uczestniczyło 28 ochotników, obojga płci. Uczestnicy zostali poddani 20 minutowej ekspozycji PM (f=7 Hz, B=330 nT). Badania przeprowadzono w roku 2003. Przeprowadzone analizy wskazują, że organizm człowieka jest wrażliwy na ekspozycję "bardzo słabego" PM, następują zmiany wartości wariancji oraz wartość skutecznej sygnału EEG.
In the author's research program to investigate the effects of infrasound exposure on the human body, tests were performed in a Hungarian type pressure cabin. The applied stimuli were generated by electrodynamic speakers GDB 30/80. Apart from sound exposure, the excitation was applied in the form of electromagnetic field (EMF). The electric field was eliminated by Faraday cage and magnetic field (MF) (f=7 Hz, B=330 nT)remained as a disturbing agent. The author put forward a hypothesis that that low frequency magnetic field might affect human body. Variance and the effective value of EEG signal are taken as estimates the effects of PM exposure. The test group included 28 volunteers, both males and females. They were subjected to 20 min of MF exposure (f=7 Hz, B=330 nT). Tests were performed in 2003. The research data reveal human sensitivity to the 'weak' field exposure', which is borne out by the obtained variance values and effective values of EEG signals.
Źródło:
Diagnostyka; 2007, 1(41); 49-53
1641-6414
2449-5220
Pojawia się w:
Diagnostyka
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Infrasound and low frequency noise of a wind turbine
Autorzy:
Wojsznis, M.
Szulczyk, J.
Powiązania:
https://bibliotekanauki.pl/articles/128032.pdf
Data publikacji:
2014
Wydawca:
Politechnika Poznańska. Instytut Mechaniki Stosowanej
Tematy:
low frequency noise
infrasound
wind turbine
hałas niskoczęstotliwościowy
infradźwięki
turbina wiatrowa
Opis:
The paper presents noise evaluation for a 2 MW wind turbine. The obtained results have been analyzed with regard to infrasound and low frequency noise generated during work of the wind turbine. The evaluation was based on standards and decrees binding in Poland. The paper presents also current literature data on the influence of the infrasound and low frequency noise on a human being. It has been concluded, that the permissible levels of infrasound for the investigated wind turbine were not exceeded.
Źródło:
Vibrations in Physical Systems; 2014, 26; 327-334
0860-6897
Pojawia się w:
Vibrations in Physical Systems
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
An Improved MSA Model for Evaluating the Sound Transmission Loss of a Rectangular Plate for Diffuse Field Incidence
Autorzy:
Kim, Myong-Jin
Won, Kyong-Su
Ri, Chol-Su
Powiązania:
https://bibliotekanauki.pl/articles/176309.pdf
Data publikacji:
2019
Wydawca:
Polska Akademia Nauk. Czasopisma i Monografie PAN
Tematy:
transmission loss
low frequency range
natural vibration mode
diffuse field incidence
Opis:
This paper presents an approximate analytical model for estimating the transmission loss (TL) of a finite rectangular plate in the low frequency range, which is based on the modal summation approach (MSA) taking into account the modal radiation impedance and fluid loading. The mode-dependent radiation resistance is calculated using the Rayleigh integral. The fluid loading is taken into account through the natural frequency modified by the added mass. The results are compared with the ones of Statistical Energy Analysis (SEA) coupled with FEM and FEM coupled with BEM. In addition, the effects of the various vibration modes and the fluid loading on TL, and a way for reducing the calculation time are discussed.
Źródło:
Archives of Acoustics; 2019, 44, 2; 259-265
0137-5075
Pojawia się w:
Archives of Acoustics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Analysis of a Geometrical-Stiffening Membrane Acoustic Metamaterial with Individually Tunable Multi-Frequencies
Autorzy:
Zhao, Junjuan
Li, Xianhui
Thompson, David
Wang, Yueyue
Wang, Wenjiang
Zhu, Liying
Liu, Yunan
Powiązania:
https://bibliotekanauki.pl/articles/1953515.pdf
Data publikacji:
2021
Wydawca:
Polska Akademia Nauk. Czasopisma i Monografie PAN
Tematy:
membrane acoustic metamaterial
nonlinear geometric stiffening
low frequency tuning
sound transmission
Opis:
To realize a structure which can be conveniently tuned to multiple and wideband frequency ranges, a geometrical-stiffening membrane acoustic metamaterial (MAM) with individually tunable multiple frequencies is presented. The MAM is realized by a stacked arrangement of two membrane-magnet elements, each of which has a membrane with a small piece of steel attached in the centre. It can be tuned individually by adjusting the position of its compact magnet. The normal incidence sound transmission loss of the MAM is investigated in detail by measurements in an impedance tube. The test sample results demonstrate that this structure can easily achieve a transmission loss with two peaks which can be shifted individually in a wide low-frequency range. A theoretical consideration is analysed, the analysis shows that the magnetic effect related to this distance leads to a nonlinear attractive force and, consequently, nonlinear geometrical stiffening in each membrane-magnet element, which allows the peaks to be shifted. A reasonable design can make the structure have a good application prospect for low-frequency noise insulation where there is a need to adjust the transmission loss according to the spectrum of the noise source.
Źródło:
Archives of Acoustics; 2021, 46, 1; 87-93
0137-5075
Pojawia się w:
Archives of Acoustics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Measurement of Compound Sound Sources with Adaptive Spatial Radiation for Low-Frequency Active Noise Control Applications
Autorzy:
Giouvanakis, Marios
Sevastiadis, Christos
Papanikolaou, George
Powiązania:
https://bibliotekanauki.pl/articles/1953496.pdf
Data publikacji:
2021
Wydawca:
Polska Akademia Nauk. Czasopisma i Monografie PAN
Tematy:
Low-Bl loudspeakers
compound sound sources
adaptive spatial radiation
active low-frequency noise control
Opis:
The proposed compound sound sources for low-frequency noise control applications are composed of dipole sources. Their spatial radiation, which is critical in the modal field of small, closed spaces, is intended to be controlled with independent driving signals of each dipole. The need for small and efficient low-frequency elementary monopole sources led to the proposed vented sub-woofer loudspeaker design with low force factor (low-Bl) drivers. The investigated sources are set up in quadrupole configurations and measured in terms of polar near field response patterns to verify the theoretical predictions. The measurement results consist of the validation of the proposed compound sound sources on the implementation of active noise control problems in the low-frequency range. Also, their small size and modular construction make them interesting for use in other applications.
Źródło:
Archives of Acoustics; 2021, 46, 2; 205-212
0137-5075
Pojawia się w:
Archives of Acoustics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Observations of Different Type of Bursts Associated with M 6.3 Solar Flares
Autorzy:
Hamidi, Z. S.
Shariff, N. N. M.
Powiązania:
https://bibliotekanauki.pl/articles/412558.pdf
Data publikacji:
2014
Wydawca:
Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
Tematy:
sun
low frequency
solar radio
burst
type III
type U
e-CALLISTO
Opis:
Variation of solar bursts due to solar flares such as type an isolated type III , a complex type III, U is being highlighted. These bursts occurred on 9th March 2012 at the National Space Centre, Sg. Lang, Selangor, Malaysia Here, we study a unique case with a combination of two types burst associated with solar flare and CMEs. Our observation is focused on the low frequency region starting from 150 MHz till 400 MHz. We found that a solar flare type solar flare type M 6.3 which occurred in active region AR 1429 starting from 3:32 UT and ending at 05:00 UT. The flare has been confirmed to be the largest flare since 2005. Some physical parameters will be measured. We then compared our results with X-ray data from NOAA Space Weather Prediction Centre (SWPC).
Źródło:
International Letters of Chemistry, Physics and Astronomy; 2014, 4; 29-36
2299-3843
Pojawia się w:
International Letters of Chemistry, Physics and Astronomy
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The Tendencies and Timeline of the Solar Burst Type II Fragmented
Autorzy:
Hamidi, Z. S.
Shariff, N. N. M.
Monstein, C.
Powiązania:
https://bibliotekanauki.pl/articles/412634.pdf
Data publikacji:
2014
Wydawca:
Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
Tematy:
sun
low frequency
solar radio
burst
type II
type III
e-CALLISTO
Opis:
We report the timeline of the solar radio burst Type II that formed but fragmented at certain point based on the eruption of the solar flare on 13th November 2012 at 2:04:20 UT. The active region AR 1613 is one of the most active region in 2012. It is well known that the magnetic energy in the solar corona is explosively released before converted into the thermal and kinetic energy in solar flares. In this work, the Compound Astronomical Low-frequency, Low-cost Instrument for Spectroscopy Transportable Observatories (CALLIISTO) system is used in obtaining a dynamic spectrum of solar radio burst data. There are eight active regions and this is the indicator that the Sun is currently active. Most the active regions radiate a Beta radiation. The active regions 1610, 1611 and 1614 are currently the largest sunspots on the visible solar disk. There is an increasing chance for an isolated M-Class solar flare event. It is also expected that there will be a chance of an M flare, especially from AR 1614 and 1610. Although these two observations (radio and X-rays) seem to be dominant on the observational analysis, we could not directly confirmed that this is the only possibility, and we need to consider other processes to explain in detailed the injection, energy loss and the mechanism of the acceleration of the particles. In conclusion, the percentage of energy of solar flare becomes more dominant rather than the acceleration of particles through the Coronal Mass Ejections (CMEs) and that will be the main reason why does the harmonic structure of type II burst is not formed. This event is one fine example of tendencies solar radio burst type III, which makes the harmonic structure of solar radio burst type II fragmented.
Źródło:
International Letters of Chemistry, Physics and Astronomy; 2014, 12; 84-102
2299-3843
Pojawia się w:
International Letters of Chemistry, Physics and Astronomy
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Dobór warstwowych zabezpieczeń przeciwhałasowych - wytyczne dla projektantów
Choosing good layer noise protections – guidelines for designers
Autorzy:
Kaczmarska, A.
Engel, Z.
Sikora, J.
Powiązania:
https://bibliotekanauki.pl/articles/179916.pdf
Data publikacji:
2005
Wydawca:
Centralny Instytut Ochrony Pracy
Tematy:
hałas
ochrona przed hałasem
hałas niskoczęstotliwościowy
noise
noise protection
low-frequency noise
Opis:
Hałas niskoczęstotliwościowy jest zwykle bardzo słabo redukowany przez typowe zabezpieczenia przeciwhałasowe. W artykule przedstawiono wyniki badań dotyczące izolacyjności akustycznej elementów budowlanych warstwowych zabezpieczeń przeciwhałasowych w zakresie niskich częstotliwości oraz zalecenia dla projektantów dotyczące prawidłowego doboru warstwowych zabezpieczeń przeciwhałasowych w tym zakresie.
Low-frequency noise is not normally much reduced with conventional noise protections. This paper presents the results of investigations of the sound insulation of building elements in layer noise protections in the low-frequency range. It also presents guidelines for designers regarding a good choice of layer noise protection in this range.
Źródło:
Bezpieczeństwo Pracy : nauka i praktyka; 2005, 6; 10-13
0137-7043
Pojawia się w:
Bezpieczeństwo Pracy : nauka i praktyka
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Ustroje rezonatorowe obniżające hałas niskoczęstotliwościowy w kabinach przemysłowych
Autorzy:
Kaczmarska, A.
Augustyńska, D.
Engel, Z.
Powiązania:
https://bibliotekanauki.pl/articles/180162.pdf
Data publikacji:
2000
Wydawca:
Centralny Instytut Ochrony Pracy
Tematy:
hałas
ochrona przed hałasem
hałas niskoczęstotliwościowy
noise
noise protection
low frequency noise
Źródło:
Bezpieczeństwo Pracy : nauka i praktyka; 2000, 11; 14-16
0137-7043
Pojawia się w:
Bezpieczeństwo Pracy : nauka i praktyka
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Wielokanałowy system akwizycji sygnałów wolnozmiennych
Multichannel low frequency signal acquisition system
Autorzy:
Golijanek-Jędrzejczyk, A.
Kuciński, M.
Rafiński, L.
Powiązania:
https://bibliotekanauki.pl/articles/151750.pdf
Data publikacji:
2012
Wydawca:
Stowarzyszenie Inżynierów i Techników Mechaników Polskich
Tematy:
karta pomiarowa
DAQ
sygnał wolnozmienny
STM32
acquisition card
low frequency signal
Opis:
W artykule zaprezentowano urządzenie służące do pomiaru szesnastu sygnałów napięciowych wolnozmiennych. Przeznaczeniem zaprojektowanego urządzenia jest ułatwienie czynności serwisowych nowoczesnych urządzeń elektronicznych. Informacja o stanie napięć w kluczowych punktach układu (często dostępnych poprzez złącze diagnostyczne) pozwala w sposób natychmiastowy ocenić powód usterki. Założeniem projektowym było utrzymanie niskiej ceny bez utraty kluczowej funkcjonalności.
Service operations always begin with a diagnosis of the malfunctioning device. Trustworthy methods for localisation of a source of damage are key to fast restoration of the equipment efficiency. Most of present electronic equipment have diagnostic connectors which simplify this operation. A measurement of significant voltage signals is the easiest approach to find a failure. In this paper the principles of functioning and a manner of realization of a multichannel low frequency signal acquisition system are presented. The core of the system is a modern microcontroller STM32F103 [1] based on ARM CortexM3 architecture. As a result of this selection a low cost but still powerful acquisition device is built. A low measurement frequency is the effect of project requirements - power supply malfunction is a frequent cause of electrical devices malfunctions. The measurement and analysis of high speed digital transmission signals is a subject of a separate diagnosis problem and is not discussed in the paper. The measurement device design is as simple as possible as an effect of nonindustrial environment and low cost elements used. Tests proved a sufficient level of robustness and measurement ability for the desired diagnostic application. Professional manufacturing of the device is planned after extensive testing.
Źródło:
Pomiary Automatyka Kontrola; 2012, R. 58, nr 11, 11; 909-911
0032-4140
Pojawia się w:
Pomiary Automatyka Kontrola
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Investigation on a Broken Solar Burst Type II during High Activities in AR1613 on 13th November 2012
Autorzy:
Hamidi, Z. S.
Shariff, N. N. M.
Monstein, C.
Zulkifli, W. N. A. W.
Ibrahim, M. B.
Arifin, N. S.
Amran, N. A.
Powiązania:
https://bibliotekanauki.pl/articles/411666.pdf
Data publikacji:
2014
Wydawca:
Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
Tematy:
sun
low frequency
solar radio
burst
type II
type III
e-CALLISTO
Opis:
The present article is an attempt to analyze the solar burst Type II observations based on solar flare and Coronal Mass Ejections (CMEs) events. We choose an intriguing type II radio burst with a velocity of 1193 kms-1 that occurred on 2012 November 13 at 2:04:20 UT. In this case, the study of solar radio burst type III is of paramount importance because of the fact that it helps to gain an insight of generation mechanisms of solar flare and Coronal Mass Ejections (CMEs) phenomena. Here, we have got a reasonably clear idea of the various forms under which the type III continuum emission may appear and potentially form a type II burst. However, in this case, the Type II solar burst only successfully forms a fundamental structure within the first few minute period, but broken suddenly before evolve a harmonic structure. This phenomenon is very interesting to be tackled and study. How the burst suddenly broken is still ongoing research seems the event is very rare and hard to be proved. There are a few questions that cause this unique situation which related to: (i) the intensity and duration of type III burst which also related to the classification of solar flare (ii) the probabilities CMEs to occur during that time and also the factor of the total amount of massive burst that exploded, Thus, we can conclude that the solar burst type III event still tells us an enigmatic characteristic from time to time due to the relationship of energetic particles and streams of particles with coronal magnetic fields and the pattern of Sun activity due to the 24th solar cycle. It might an interesting to study in detail the main factor that caused the Type II solar burst broken. Indirectly, it might because of the very intense of solar flares that make the percentage of energy of solar flare become more dominant rather than the acceleration of particles through the Coronal Mass Ejections. Thus, we realize that the potential energy during this event is higher than the kinetic energy of the particles.
Źródło:
International Letters of Chemistry, Physics and Astronomy; 2014, 9; 8-15
2299-3843
Pojawia się w:
International Letters of Chemistry, Physics and Astronomy
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Wpływ pola magnetycznego niskiej częstotliwości na stres oksydacyjny w tkance mięśniowej szczura
Influence of the low frequency magnetic field on the parameters of oxidative stress in rats muscles
Autorzy:
Ciejka, E.
Skibska, B.
Gorąca, A.
Powiązania:
https://bibliotekanauki.pl/articles/261224.pdf
Data publikacji:
2010
Wydawca:
Politechnika Wrocławska. Wydział Podstawowych Problemów Techniki. Katedra Inżynierii Biomedycznej
Tematy:
pole magnetyczne niskiej częstotliwości
stres oksydacyjny
low frequency magnetic field
oxidative stress
Opis:
Wolne rodniki (WR) to atomy lub cząsteczki, posiadające wolne niesparowane elektrony. Ich nadmiar prowadzi do rozwoju stresu oksydacyjnego - przyczyny wielu chorób nowotworowych, neurodegeneracyjnych, zapalnych oraz starzenia się organizmu. Głównymi egzogennymi źródłami wolnych rodników są m.in.: zanieczyszczenia przemysłowe, dym tytoniowy, promieniowanie jonizujące oraz pola magnetyczne. Cel. Celem pracy jest ocena działania pola magnetycznego niskiej częstotliwości na proces peroksydacji lipidów w tkance mięśniowej zwierząt doświadczalnych. Materiał i metody. Materiał badawczy stanowiły dorosłe szczury, samce rasy Sprague-Dawley w wieku 3-4 miesięcy. Zwierzęta podzielono na 3 grupy badawcze: I - grupa kontrolna; II grupa poddana działaniu pola magnetycznego o następujących parametrach: 7 mT, 40 Hz, 30 min/dzień, 2 tyg.; III grupa - poddana działaniu pola magnetycznego o parametrach: 7 mT, 40 Hz, 60 min/dzień, 2 tyg. U badanych zwierząt wykonano pomiar stężenia produktów peroksydacji lipidów (TBARS[h1]) w homogenatach tkanki mięśniowej po zakończeniu ekspozycji na działanie pola magnetycznego. Wyniki. Po działaniu zmiennego pola magnetycznego o częstotliwości 40 Hz, indukcji 7 mT, w czasie 30, 60 min/dzień przez 2 tygodnie zaobserwowano wzrost stężenia TBARS w tkance mięśniowej szczura. Wnioski. Pole magnetyczne niskiej częstotliwości (Low Frequency Magnetic Field - LFMF) o parametrach stosowanych w magnetoterapii wywołuje istotne zmiany w procesie generacji reaktywnych form tlenu.
Free radicals (FR) are atoms or molecules with unpaired electrons. They may lead to the development of the oxidative stress, which is a cause of many neoplastic, neurodegenerative, inflammatory diseases and aging of the organism. The main exogenous sources of free radicals are among others: industrial pollution, tobacco smoke, ionizing radiation, and magnetic field. Goal: The aim of this study was to evaluate the influence of the low magnetic field on the parameters of the oxidative stress (TBARS[h2]) in rat's muscles. Materials and methods. Thirty male rats, weight of 280-300 g were randomly divided into three experimental groups: control I and treatment II i III (Low Frequency Magnetic Field LFMF). Animals in the group II were exposed to the LFMF of the following parameters: frequency 40 Hz, induction 7 mT for 0.5 h/day for 14 days (this kind of the ELFMF is mostly used in magnetotherapy), while the group III was subjected to the field: 40 Hz, 7 mT for 1h/day for 14 days. Control rats were kept in the separate room and were not exposed to the to ELFMF. Immediately, after the last exposure, the part of muscles was taken under pentobarbital anaesthesia. The effects of the exposure to the LFMF on the oxidative states were assessed by the measurements of concentration of TBARS in muscles homogenates. Results. Exposure to the LFMF with the following parameters: 40 Hz, 7 mT, 30 and 60min/day for 2 weeks caused significant increase in TBARS concentration in the muscles homogenates. Conclusion. Low magnetic field used in magnetotherapy causes the significant changes of the process of generation of the reactive forms of oxygen in the muscles.
Źródło:
Acta Bio-Optica et Informatica Medica. Inżynieria Biomedyczna; 2010, 16, 3; 224-226
1234-5563
Pojawia się w:
Acta Bio-Optica et Informatica Medica. Inżynieria Biomedyczna
Dostawca treści:
Biblioteka Nauki
Artykuł

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