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Wyszukujesz frazę "pressure sensitivity" wg kryterium: Temat


Wyświetlanie 1-10 z 10
Tytuł:
Measurement of pressure sensitivity of modal birefringence of birefringent optical fibers using a Sagnac interferometer
Autorzy:
Kaczmarek, C
Wójcik, W
Powiązania:
https://bibliotekanauki.pl/articles/174434.pdf
Data publikacji:
2015
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
birefringent fiber
birefringence
pressure sensitivity
Opis:
The paper presents a method of measuring the sensitivity of modal birefringence to pressure in birefringent optical fibers, based on a Sagnac interferometer with a birefringent fiber. In this method, the pressure sensitivity of modal birefringence of the optical fiber is determined on the basis of the measurement of the pressure sensitivity of the Sagnac interferometer including the fiber being measured, and the measurement of the group modal birefringence of that fiber, which is also performed by using the Sagnac interferometer. Utilizing the above method, measurements were performed of the pressure sensitivity of modal birefringence of birefringent optical fibers: a photonic crystal fiber and a bow-tie fiber, in the wavelength range 1460–1600 nm. Presented are the results of these measurements and their comparison with the results obtained by using different methods for the same types of fibers.
Źródło:
Optica Applicata; 2015, 45, 1; 5-14
0078-5466
1899-7015
Pojawia się w:
Optica Applicata
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
An extension of Burzyński hypothesis of material effort accounting for the third invariant of stress tensor
Rozszerzenie hipotezy wytężenia burzyńskiego uwzględniające wpływ trzeciego niezmiennika tensora naprężenia
Autorzy:
Pęcherski, R. B.
Szeptyński, P.
Nowak, M.
Powiązania:
https://bibliotekanauki.pl/articles/351280.pdf
Data publikacji:
2011
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
warunek plastyczności Burzyńskiego
kąt Lodego
trzeci niezmiennik dewiatora tensora naprężenia
Burzyński yield condition
strength differential effect
pressure sensitivity
Lode angle
third invariant of stress tensor deviator
Opis:
The aim of the paper is to propose an extension of the Burzyński hypothesis of material effort to account for the influence of the third invariant of stress tensor deviator. In the proposed formulation the contribution of the density of elastic energy of distortion in material effort is controlled by Lode angle. The resulted yield condition is analyzed and possible applications and comparison with the results known in the literature are discussed.
Celem pracy jest propozycja rozszerzenia hipotezy wytężenia Burzyńskiego dla uwzględnienia wpływu trzeciego niezmiennika dewiatora tensora naprężenia. W proponowanym sformułowaniu udział gęstości sprężystej energii odkształcenia postaciowego jest kontrolowany przez funkcję zależną od kąta Lodego. Wyprowadzony warunek plastyczności porównano ze znanymi wynikami z literatury oraz przedyskutowano jego możliwe zastosowania.
Źródło:
Archives of Metallurgy and Materials; 2011, 56, 2; 503-508
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Assessment of Role of Job Components and Individual Parameters on the Raised Blood Pressure in a Noisy Industry
Autorzy:
Abbasi, Milad
Farhang-Dehghan, Somayeh
Yazdanirad, Saeid
Mehri, Ahmad
Kolahdouzi, Malihe
Fallah Madvari, Rohollah
Akbarzadeh, Arash
Ghaljahi, Maryam
Powiązania:
https://bibliotekanauki.pl/articles/177433.pdf
Data publikacji:
2019
Wydawca:
Polska Akademia Nauk. Czasopisma i Monografie PAN
Tematy:
noise exposure
noise annoyance
noise sensitivity
triglyceride
cholesterol
raised blond pressure
Opis:
The present study aimed to determine the role of job components and individual parameters on the raised blood pressure among male workers of textile industry who were exposed to continuous high noise level. Information of all eligible subjects including demographic and individual characteristics, medical history and job characteristics were obtained by direct interview and referring to the medical records. All blood pressure measurements were done using mercury sphygmomanometer in the morning before work. The 8-hours equivalent A-weighted sound pressure level, the level of blood cholesterol and triglyceride, and noise annoyance was determined for each worker. As the result of weighted regression in path analysis (direct effect), only the work shift did not have a significant effect on blood pressure among the studiem variables. It can be seen that variables including the level of triglyceride, cholesterol, and noise exposure have the most direct effects on blood pressure. The results of total effects showed that variables, including using the hearing protection device, age, work experience and visibility of sound source, did not have a significant effect on blood pressure. The results of this study indicate that occupational noise exposure alone and combined with other job components and individual parameters is associated with raised blond pressure. However, noise exposure was probably a stronger stressor for increased blood pressure.
Źródło:
Archives of Acoustics; 2019, 44, 3; 575-584
0137-5075
Pojawia się w:
Archives of Acoustics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Cardiovascular system parameters in participants of Arctic expeditions
Autorzy:
Pankova, Nataliya B.
Alchinova, Irina B.
Cherepov, Anton B.
Yakovenko, Elena N.
Karganov, Mikhail Y.
Powiązania:
https://bibliotekanauki.pl/articles/2116502.pdf
Data publikacji:
2020-10-20
Wydawca:
Instytut Medycyny Pracy im. prof. dra Jerzego Nofera w Łodzi
Tematy:
adaptation
heart rate variability
cardiovascular system
climate
blood pressure variability
baroreflex sensitivity
Opis:
ObjectivesA method of continuous heart rate (HR) and blood pressure (BP) recording was used for the evaluation of the cardiovascular system parameters in participants of short-term (<1 month) high-latitude expeditions, in comparison with the parameters of residents of Central Russia and the Arctic region.Material and MethodsA dynamic examination of participants of Arctic expeditions (30 men, residents of middle-latitude regions, aged 46.7±1.7 years), workers permanently living in Central Russia (the Moscow region, 44 men, aged 46.7±1.0 years) and residents of the North (the Murmansk region, 35 men, aged 46.6±1.3 years) was performed. The authors used a spiroartheriocardiorythmograph allowing the parallel recording of HR, BP, spectral characteristics of HR variability (HRV) and the variability of systolic BP (sBP) and diastolic BP (dBP), cardiac performance parameters, and spontaneous baroreflex sensitivity (BRS). The parameters were recorded at rest, in a sitting position, over 2 min.ResultsThe basic clinical parameters (HR, BP and cardiac performance) did not differ in the workers living in different climatic zones. However, the residents of the North demonstrated a lower total power (TP) of the dBP variability spectrum and a lower relative power of the high-frequency (HF) range in both the sBP and dBP variability spectra. The participants of expeditions to the North had a lower TP of the HRV spectrum (in comparison with both control groups) that did not change during the expeditions; BRS was reduced, while the TP of the sBP spectrum was increased in comparison with the corresponding parameters obtained from the residents of circumpolar regions, and decreased during the expedition in parallel with a decrease in the sBP values. The TP of both the sBP and dBP variability spectra, as well as the power of the HF range in these spectra, were similar in the participants of expeditions to those obtained from the residents of Central Russia, and they considerably surpassed the corresponding parameters in the northerners surveyed.ConclusionsThe revealed peculiarities of the cardiovascular system in the participants of high-latitude expeditions can be considered as correlates of positive, and adequate in terms of the physiological value, adaptive shifts in the autonomous regulation of the cardiovascular system.
Źródło:
International Journal of Occupational Medicine and Environmental Health; 2020, 33, 6; 819-828
1232-1087
1896-494X
Pojawia się w:
International Journal of Occupational Medicine and Environmental Health
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Influence of Filler Surface Modification on Static and Dynamic Mechanical Responses of Rice Husk Reinforced Linear Low-Density Polyethylene Composites
Autorzy:
Omar, Mohd Firdaus
Al Bakri Abdullah, Mohd Mustafa
Ting, Sam Sung
Jeż, Bartłomiej
Nabiałek, Marcin
Md Akil, Hazizan
Zulkepli, Nik Noriman
Abd Rahim, Shayfull Zamree
Azmi, Azida
Powiązania:
https://bibliotekanauki.pl/articles/2106572.pdf
Data publikacji:
2022
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
silane coupling agents
strain rate
universal testing machine
split Hopkinson pressure bar
strain rate sensitivity
Opis:
Filler surface modification has become an essential approach to improve the compatibility problem between natural fillers and polymer matrices. However, there is limited work that concerns on this particular effect under dynamic loading conditions. Therefore, in this study, both untreated and treated low linear density polyethylene/rice husk composites were tested under static (0.001 s-1, 0.01 s-1 and 0.1 s-1) and dynamic loading rates (650 s-1, 900 s-1 and 1100 s-1) using universal testing machine and split Hopkinson pressure bar equipment, respectively. Rice husk filler was modified using silane coupling agents at four different concentrations (1, 3, 5 and 7% weight percentage of silane) at room temperature. This surface modification was experimentally proven by Fourier transform infrared and Field emission scanning electron microscopy. Results show that strength properties, stiffness properties and yield behaviour of treated composites were higher than untreated composites. Among the treated composites, the 5% silane weight percentage composite shows the optimum mechanical properties. Besides, the rate of sensitivity of both untreated and treated composites also shows great dependency on strain rate sensitivity with increasing strain rate. On the other hand, the thermal activation volume shows contrary trend. For fracture surface analysis, the results show that the treated LLDPE/RH composites experienced less permanent deformation as compared to untreated LLDPE/RH composites. Besides, at dynamic loading, the fracture surface analysis of the treated composites showed good attachment between RH and LLDPE.
Źródło:
Archives of Metallurgy and Materials; 2022, 67, 2; 507--519
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Experimental study on the effects of vibrational frequency on the permeability of gas-containing coal rocks
Autorzy:
Bairu, Zhu
Yang, Song
Beining, Wu
Yongqi, Li
Powiązania:
https://bibliotekanauki.pl/articles/1853881.pdf
Data publikacji:
2021
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
wibracje
przepuszczalność
ciśnienie gazu
gas-containing coal rock
low-frequency vibration
gas pressure
permeability
sensitivity coefficient
Opis:
Low-frequency mechanical vibrations can trigger disasters such as coal-gas outbursts. An in-house “vibration-triaxial stress-seepage” experimental apparatus was used to measure the gas flow rate of rock specimens with varying vibrational frequency, gas pressure, and confining pressure. The results of these tests were then used to derive expressions that describe how the permeability of gas-containing coal rocks is related to these aforementioned factors. In addition, sensitivity coefficients were defined to characterise the magnitude of the permeability response to each permeability-affecting factor (i.e., vibrational frequency and gas pressure). The following insights were gained, regarding the effects of vibrational frequency on the permeability of gas-containing coal rocks: (1) If gas pressure and confining pressure are fixed, the permeability of gas-containing coal rocks rapidly increases, before gradually decreasing, with increasing vibrational frequency. Thus, the permeability of the gas-containing coal rock is always larger with vibrations than without. (2) If vibrational pressure and confining pressure are fixed, the relationship between the permeability of gas-containing coal rocks and gas pressure is consistent with the “Klinkenberg effect,” i.e., the permeability initially decreases, and then increases, with increasing gas pressure. (3) The change in permeability induced by each unit change in gas pressure is proportional to the gas pressure sensitivity coefficient. (4) The change in permeability induced by each unit change in vibrational frequency is proportional to the vibrational frequency sensitivity coefficient.
Źródło:
Archives of Mining Sciences; 2021, 66, 2; 265-278
0860-7001
Pojawia się w:
Archives of Mining Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Regional features analysis of plugged holes of dense phase gas-solid separation fluidized bed
Autorzy:
Zhang, B.
Zhao, Y.
Luo, Z.
Song, S.
Duan, C.
Dong, L.
Powiązania:
https://bibliotekanauki.pl/articles/109699.pdf
Data publikacji:
2014
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
gas-solid fluidized bed for separation
pressure fluctuation
plugged holes regions
features analysis
plugged holes sensitivity
Opis:
In contrast to traditional coal separation, dry separation does not require water and does not cause water pollution. Dense phase gas–solid fluidized beds are used for dry separation. The plugged holes in the air distributor should be tested to ensure the stability of these beds for particle separation. The pressure fluctuation is sensitive to these plugged holes. This sensitivity can be tested and diagnosed by determining the standard deviation of the pressure fluctuation. In areas with partial blockage, that is the areas with weak fluidization, a decrease in the volume fraction of the particles and in the pressure differences in the transverse of the bed results in an increase of the standard deviation of the pressure fluctuation, thereby stimulating the lateral mixing of medium-sized particles. The standard deviation and the mixing intensity decrease axially. The value of sensitivity of the plugged holes in the air distributor decreases as the height of the bed increases. The features of air distributors affect the surrounding areas. The distribution law determining the influence of plugged holes on the beds is symmetrical. As the blockage of the fluidized bed distributor region increases, the mean square error of the pressure fluctuation in the related regions increases. The intensity of the effect is proportional to the distance to the plugged holes.
Źródło:
Physicochemical Problems of Mineral Processing; 2014, 50, 2; 667-679
1643-1049
2084-4735
Pojawia się w:
Physicochemical Problems of Mineral Processing
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Badania wrażliwości jabłek na stłuczenia przy obciążeniach o charakterze udarowym
Investigation of apples sensitivity to bruising at impact loading
Autorzy:
Komarnicki, P.
Stopa, R.
Powiązania:
https://bibliotekanauki.pl/articles/290416.pdf
Data publikacji:
2013
Wydawca:
Polskie Towarzystwo Inżynierii Rolniczej
Tematy:
wrażliwość na stłuczenie
udar
nacisk powierzchniowy
objętość deformacji
jabłko
sensitivity to bruising
impact
surface pressure
deformation volume
apple
Opis:
W pracy zaprezentowano wyniki badań wpływu obciążeń o charakterze udarowym na wrażliwość jabłek na stłuczenia przy zmiennych wartościach wysokości zrzutu i ilości uderzeń. Wyznaczono wartości impulsów sił, pola powierzchni styku oraz nacisków powierzchniowych w funkcji wysokości i ilości stłuczeń. Wykonano dokumentację fotograficzną, która posłużyła do przeprowadzenia komputerowej analizy obrazów w celu wyznaczenia objętości zniszczonej tkanki oraz przedstawienia oceny jakościowej wrażliwości jabłek na stłuczenia. Pomiary przy obciążeniach udarowych przeprowadzono za pomocą aparatury firmy Tekscan na specjalnie zbudowanym stanowisku badawczym, którego działanie oparte było na zasadzie wahadła. Analiza zmian objętości deformacji w funkcji sił chwilowych podczas uderzenia wykazała, że przy wzroście obciążenia z 57 N do 106 N następuje gwałtowny wzrost wartości objętości z 363 do 6233 mm3. Analiza nacisków powierzchniowych potwierdziła występowanie maksymalnych wartości dla pierwszych uderzeń jabłek, największą zaś wartość wynoszącą 0,256 MPa uzyskano dla wysokości zrzutu równej 250 mm. Niezależnie od wysokości zrzutu, po dziesięciu uderzeniach naciski powierzchniowe stabilizują się na poziomie 0,160 MPa. Stwierdzono, że badane jabłka wykazują dużą wrażliwość pod wpływem obciążeń o charakterze udarowym. Oszacowano wysokość zrzutu około 30 mm, którą można uznać za wartość niewywołującą odkształceń o charakterze plastycznym.
The paper presents results of research on the influence of impact loading on sensitivity of apples to bruising at variable values of the drop height and the number of impacts. Values of power impulses, contact surface area and surface pressure as the function of height and the number of bruises were determined. Photographic documentation was prepared, which served for carrying out a computer analysis of images in order to determine the volume of the damaged tissue and for presenting the assessment of quality sensitivity of apples to impact. Measurements at impact loading were carried out with the use of Tekscan apparatus on a specially constructed research stand, whose operation was based on the pendulum principle. Analysis of volume changes of deformation as the function of temporary powers during impact proved that at the increase of loading from 57 N to 106 N a violent increase of the volume value from 363 do 6233 mm3 took place. Analysis of surface pressures confirmed occurrence of maximum values for first impact to apples, whereas the highest value of 2.256 MPa was obtained for the drop height amounting to 250 mm. Independently from the drop height, after ten impacts, surface pressures stabilize at the level 0.160 MPa. It was determined that the investigated apples prove high sensitivity under the influence of impact loading. The drop height was estimated to be 30 mm, which may be recognized as the value, which does not cause plastic deformations.
Źródło:
Inżynieria Rolnicza; 2013, R. 17, nr 3, t. 2, 3, t. 2; 131-143
1429-7264
Pojawia się w:
Inżynieria Rolnicza
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Reliability assessment and sensitivity analysis of concrete gravity dams by considering uncertainty in reservoir water levels and dam body materials
Autorzy:
Pouraminian, Majid
Pourbakhshian, Somayyeh
Noroozinejad Farsangi, Ehsan
Powiązania:
https://bibliotekanauki.pl/articles/396079.pdf
Data publikacji:
2020
Wydawca:
Uniwersytet Zielonogórski. Oficyna Wydawnicza
Tematy:
concrete dam
sensitivity analysis
hydrostatic pressure
epistemic uncertainty
failure risk
zapora betonowa
analiza wrażliwości
ciśnienie hydrostatyczne
ryzyko awarii
Opis:
An elaborate safety assessment of the Pine Flat (PF) concrete gravity dam (CGD) has been conducted in this paper. Structural analysis was performed by taking into account the uncertainties in the physical and mechanical properties of the dam body materials and the reservoir water level. The coefficient of variation of 5 and 10 percent and the Gaussian distribution (GAUS) are assigned to random variables (RVs). Sensitivity analysis (SA) of the RVs is done, and important parameters introduced. SA is done to identify the most influential RVs on the structural response. Also, the modulus of elasticity of concrete is the most effective parameter in response to horizontal deformation of the dam crest. The concrete density and US hydrostatic pressure height are the most effective parameters, and the Poisson's ratio is the insignificant parameter on the dam response. To be confident in the safety of the dam body under usual loading, including the dam weight and the upstream (US) hydrostatic pressure, the reliability index (RI) has been obtained by Monte Carlo simulation. The RI for the coefficients of variation of 5 and 10 percent were obtained at 4.38 and 2.47, respectively. If the dispersion of RVs is high, then the dam will be at risk of failure.
Źródło:
Civil and Environmental Engineering Reports; 2020, 30, 1; 1-17
2080-5187
2450-8594
Pojawia się w:
Civil and Environmental Engineering Reports
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Directional sensitivity of differential pressure sensors of gas velocity used in manual gravimetric measurements of dust emissions from stationary sources
Czułość kierunkowa różnicowo-ciśnieniowych czujników prędkości gazu stosowanych w manualnych pomiarach grawimetrycznych emisji zanieczyszczeń pyłowych ze źródeł stacjonarnych
Autorzy:
Szulikowski, J.
Kateusz, P.
Powiązania:
https://bibliotekanauki.pl/articles/205304.pdf
Data publikacji:
2015
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
directional sensitivity
differential pressure sensors of gas velocity
flue gas velocity measurements
dust emission measurements
Pitot tube
zero pressure dust sampling probe
zanieczyszczenia pyłowe
emisja pyłów
czułość kierunkowa
różnicowo-ciśnieniowy czujnik prędkości
rurka Pitota
pyłowa sonda zerowa
Opis:
Manual measurements of distribution of gas velocity in conduits of flue gas installations using systems with differential pressure sensors of velocity are often performed for the requirements of determining emissions of dust pollutants from industrial process plants to the atmosphere. The aim is to determine an axial velocity profile. Flows in measuring sections are not always coaxial along the run of the duct; they are characterized by different directions of the velocity vector at various measuring points. The determination of actual directions of vectors of local velocities giving a guarantee of an accurate calculation of the axial velocity is often not possible from the technical point of view and the measurement of the velocity is carried out with the parallel setting of the sensor head in relation to the axis and the walls of the conduit. Then the knowledge of the directional sensitivity of the applied velocity sensor allows either to eliminate the axial velocity measurement error or to take it into account by the uncertainty of this measurement. For specific situations of two-dimensional variation of direction of the velocity vector, the directional sensitivity characteristics and in consequence the characteristics of error have been determined for three sensors adopted to tests: a zero pressure dust sampling probe with the anemometric function as an element of the gravimetric dust sampler and comparatively - two commonly used Pitot tubes: types S and L.
Na potrzeby określania emisji zanieczyszczeń pyłowych do atmosfery z przemysłowych instalacji technologicznych często wykonywane są manualne pomiary rozkładu prędkości gazu w kanałach instalacji gazów odlotowych przy pomocy układów z różnicowo-ciśnieniowymi czujnikami prędkości. Celem jest ustalenie profilu prędkości osiowej. Przepływy w przekrojach pomiarowych nie zawsze są współosiowe z biegiem kanału; cechują się różnymi kierunkami wektora prędkości w różnych punktach pomiarowych. Ustalanie rzeczywistych kierunków wektorów prędkości lokalnych, dające gwarancję dokładnego obliczenia prędkości osiowych, często nie jest możliwe z technicznego punktu widzenia i pomiar prędkości prowadzi się przy ustawieniu głowicy czujnika równoległym w stosunku do osi i ścian kanału. Wtedy wiedza o czułości kierunkowej zastosowanego czujnika prędkości pozwala albo na wyeliminowanie błędu pomiaru prędkości osiowej, albo na uwzględnienie go poprzez niepewność tego pomiaru. Dla specyficznych sytuacji dwuwymiarowej zmienności kierunku wektora prędkości wyznaczono charakterystyki czułości kierunkowej i w konsekwencji charakterystyki błędu trzech przyjętych do badań czujników: pyłowej sondy zerowej o funkcji anemometrycznej jako elementu pyłomierza grawimetrycznego i porównawczo - dwóch powszechnie stosowanych rurek spiętrzających: typu S i L.
Źródło:
Archives of Environmental Protection; 2015, 41, 3; 83-96
2083-4772
2083-4810
Pojawia się w:
Archives of Environmental Protection
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-10 z 10

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