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Wyszukujesz frazę "thermal radiation" wg kryterium: Wszystkie pola


Tytuł:
Remedies to Thermal Radiation in Fused Silica Optical Fibers
Autorzy:
Borzycki, Krzysztof
Jaworski, Marek
Kossek, Tomasz
Powiązania:
https://bibliotekanauki.pl/articles/2200964.pdf
Data publikacji:
2023
Wydawca:
Instytut Łączności - Państwowy Instytut Badawczy
Tematy:
attenuation testing
fire resistant fiber optic cable
fire test
fused silica optical fiber
incandescent emission
interference filtering
Opis:
During fire incidents, optical fibers located with-in a fire-resistant cable are usually exposed to temperatures of 800◦C to 1000◦C. Hot fibers generate narrowband thermal (incandescent) radiation and collect broadband thermal radiation originating from the heated surroundings. The power of the second component, initially negligible, increases with time due to the rising number of fiber cracks and other defects acting as couplers for external radiation. Thermal radiation may interfere with fiber attenuation measurements performed during a fire test, but is rather unlikely to prevent data transmission with typical GbE and 10 GbE transceivers during a fire. This problem may be remedied by combining the following methods: using single mode fibers instead of multimode fibers, using bandpass filters to block thermal radiation, and selecting proper transmitter power, wavelength and photodetector.
Źródło:
Journal of Telecommunications and Information Technology; 2023, 1; 88--96
1509-4553
1899-8852
Pojawia się w:
Journal of Telecommunications and Information Technology
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Considerations on modifying basalt fabrics protecting against the thermal radiation
Autorzy:
Miśkiewicz, Pamela
Frydrych, Iwona
Powiązania:
https://bibliotekanauki.pl/articles/1179530.pdf
Data publikacji:
2017
Wydawca:
Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
Tematy:
basalt fabrics
basalt fibers
chemical vapour deposition
physical vapour deposition
protective gloves
Opis:
Due to very good thermal and mechanical properties characterizing basalt fibers and items made of them, this raw material is now more frequently used for the manufacturing various textile products. Basalt fibers on the textile market are primarily used in articles, which are designed to protect against thermal factors. The paper discusses the possibility of applying selected coatings formed by physical – PVD (Physical Vapour Deposition) or chemical CVD (Chemical Vapour Deposition) deposition of chemical compounds in the form of gaseous phase on the surface of basalt fabrics to improve their protective properties against very high temperatures affecting the clothing products.
Źródło:
World Scientific News; 2017, 76; 85-90
2392-2192
Pojawia się w:
World Scientific News
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Micropolar flow over a black isothermal plate in the presence thermal radiation
Autorzy:
Raptis, A.
Powiązania:
https://bibliotekanauki.pl/articles/1839844.pdf
Data publikacji:
2021
Wydawca:
Uniwersytet Zielonogórski. Oficyna Wydawnicza
Tematy:
płyn mikropolarny
promieniowanie cieplne
płyta izotermiczna
micropolar fluid
thermal radiation
isothermal plate
Opis:
This study numerically investigates the effects of thermal radiation on the flow over a black isothermal plate for an optically thin gray micropolar fluid. The flowing medium absorbs and emits radiation, but scattering is not included. The computational results are discussed graphically for several selected flow parameters.
Źródło:
International Journal of Applied Mechanics and Engineering; 2021, 26, 2; 235-241
1734-4492
2353-9003
Pojawia się w:
International Journal of Applied Mechanics and Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effect of thermal radiation, chemical reaction and viscous dissipation on MHD flow
Autorzy:
Zigta, B.
Powiązania:
https://bibliotekanauki.pl/articles/265728.pdf
Data publikacji:
2018
Wydawca:
Uniwersytet Zielonogórski. Oficyna Wydawnicza
Tematy:
przepływ MHD
promieniowanie cieplne
reakcja chemiczna
MHD flow
thermal radiation
chemical reaction
viscous dissipation
Opis:
This study examines the effect of thermal radiation, chemical reaction and viscous dissipation on a magnetohydro- dynamic flow in between a pair of infinite vertical Couette channel walls. The momentum equation accounts the effects of both the thermal and the concentration buoyancy forces of the flow. The energy equation addresses the effects of the thermal radiation and viscous dissipation of the flow. Also, the concentration equation includes the effects of molecular diffusivity and chemical reaction parameters. The gray colored fluid considered in this study is a non-scattering medium and has the property of absorbing and emitting radiation. The Roseland approximation is used to describe the radiative heat flux in the energy equation. The velocity of flow transforms kinetic energy into heat energy. The increment of the velocity due to internal energy results in heating up of the fluid and consequently it causes increment of the thermal buoyancy force. The Eckert number being the ratio of the kinetic energy of the flow to the temperature difference of the channel walls is directly proportional to the thermal energy dissipation. It can be observed that increasing the Eckert number results in increasing velocity. A uniform magnetic field is applied perpendicular to the channel walls. The temperature of the moving wall is high enough due to the presence of thermal radiation. The solution of the governing equations is obtained using regular perturbation techniques. These techniques help to convert partial differential equations to a set of ordinary differential equations in dimensionless form and thus they are solved analytically. The following results are obtained: from the simulation study it is observed that the flow pattern of the fluid is affected due to the influence of the thermal radiation, the chemical reaction and viscous dissipation. The increment in the Hartmann number results in the increment of the Lorentz force but a decrement in velocity of the flow. An increment in the radiative parameter results in a decrement in temperature. An increment in the Prandtl number results in a decrement in thermal diffusivity. An increment in both the chemical reaction parameter and molecular diffusivity results in a decrement in concentration.
Źródło:
International Journal of Applied Mechanics and Engineering; 2018, 23, 3; 787-801
1734-4492
2353-9003
Pojawia się w:
International Journal of Applied Mechanics and Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Sensitivity and dynamic phase response to thermal radiation of a polarization-maintaining fiber
Autorzy:
Kyselak, M.
Dvorak, F.
Maschke, J.
Vlcek, C.
Powiązania:
https://bibliotekanauki.pl/articles/173541.pdf
Data publikacji:
2018
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
fiber sensor
polarization-maintaining fiber
PMF
optical fiber
birefringence
temperature field disturbance
approximation equations
approximation parameters
Opis:
This paper deals with the phase shift development between two polarization modes in birefringent fiber, caused by body heat transfer of different temperatures. The aim is to analyze sensitivity and dynamic behaviors, which are significant when optical fiber is used as a sensor of temperature field disturbance. The analysis is based on the values measured during thermal exposure of a section of type PANDA birefringent optical fiber to heat emitted by an exposure body of chosen temperature, placed at a defined distance. The effect of heat transfer through conduction and convection is suppressed by shielding with plastic wraps. The analyzed results, the Stokes parameters and subsequent phase shift, are measured by the polarimeter. The paper follows up on previously published measurement results.
Źródło:
Optica Applicata; 2018, 48, 2; 249-261
0078-5466
1899-7015
Pojawia się w:
Optica Applicata
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Destruction of Moulding Sands with Chemical Binders Caused by the Thermal Radiation of Liquid Metal
Autorzy:
Zych, J.
Mocek, J.
Powiązania:
https://bibliotekanauki.pl/articles/382547.pdf
Data publikacji:
2015
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
sand mould
thermal destruction
thermal radiation
heating of mould
loss of strength
masa formierska
rozkład termiczny
promieniowanie cieplne
Opis:
The obtained results of heating of sand moulds with binders by means of a thermal radiation of liquid metal are presented in this study. Standard samples for measuring Rg made of the tested moulding sands were suspended at the lower part of the cover which was covering the crucible with liquid metal (cast iron), placed in the induction furnace. The authors own methodology was applied in investigations. The progressing of the samples surface layers heating process was determined as the heating time function. Samples of a few kinds of moulding sands with chemical binders were tested. Samples without protective coatings as well as samples with such coatings were tested. The influence of the thermal radiation on bending resistance of samples after their cooling was estimated. The influence of several parameters such as: time of heating, distance from the metal surface, metal temperature, application of coatings, were tested. A very fast loss of strength of moulding sands with organic binders was found, especially in cases when the distance between metal and sample surfaces was small and equaled to 10÷15 mm. Then, already after app. 15 seconds of the radiation (at Tmet=1400°C), the resistance decreases by nearly 70%. Generally, moulding sands with organic binders are losing their strength very fast, while moulding sands with water glass at first increase their strength and later slightly lose. The deposition of protective coatings increases the strength of the mould surface layers, however does not allow to retain this strength after the metal thermal radiation.
Źródło:
Archives of Foundry Engineering; 2015, 15, 4; 95-100
1897-3310
2299-2944
Pojawia się w:
Archives of Foundry Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Absorption characteristics of thermal radiation for carbon dioxide
Charakterystyka absorpcji promieniowania cieplnego dla dwutlenku węgla
Autorzy:
Kubicki, Jan
Kopczyński, Krzysztof
Młyńczak, Jarosław
Powiązania:
https://bibliotekanauki.pl/articles/2174709.pdf
Data publikacji:
2022
Wydawca:
Politechnika Lubelska. Wydawnictwo Politechniki Lubelskiej
Tematy:
absorption characteristics
saturation of absorption
thermal radiation
Schwarzschild equation
charakterystyka absorbcji
nasycenie absorbcji
promieniowanie cieplne
równanie Schwarzschilda
Opis:
The article presents graphs of absorption of thermal radiation as a function of the mass of absorbing carbon dioxide per unit of illuminated area. Experimental research was preceded by an analysis of a simplified model of radiation absorption, paying attention to the phenomenon of saturation. The results of the experimental research were compared with the theoretical ones and the discrepancies were interpreted. Based on the conclusions, suggestions were made regarding the impact of further CO2 emissions on climate change.
W artykule przedstawiono wykresy absorpcji promieniowania cieplnego w funkcji masy absorbującego dwutlenku węgla na jednostkę oświetlanej powierzchni. Badania eksperymentalne poprzedzono analizą uproszczonego modelu absorpcji promieniowania, zwracając uwagę na zjawisko nasycenia. Wyniki badań eksperymentalnych porównano z teoretycznymi, a rozbieżności zinterpretowano. Na podstawie wniosków sformułowano sugestie dotyczące wpływu dalszej emisji CO2 na zmiany klimatyczne.
Źródło:
Informatyka, Automatyka, Pomiary w Gospodarce i Ochronie Środowiska; 2022, 12, 3; 4--7
2083-0157
2391-6761
Pojawia się w:
Informatyka, Automatyka, Pomiary w Gospodarce i Ochronie Środowiska
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Heat Gain From Thermal Radiation Through Protective Clothing With Different Insulation, Reflectivity and Vapour Permeability
Autorzy:
Brode, P.
Kuklane, K.
Candas, V.
Den Hartog, E. A.
Griefahn, B.
Holmer, I.
Meinander, H.
Nocker, W.
Richards, M.
Havenith, G.
Powiązania:
https://bibliotekanauki.pl/articles/90351.pdf
Data publikacji:
2010
Wydawca:
Centralny Instytut Ochrony Pracy
Tematy:
protective clothing
heat stress
heat budget models
thermal manikin
Opis:
The heat transferred through protective clothing under long wave radiation compared to a reference condition without radiant stress was determined in thermal manikin experiments. The influence of clothing insulation and reflectivity, and the interaction with wind and wet underclothing were considered. Garments with different outer materials and colours and additionally an aluminised reflective suit were combined with different number and types of dry and pre-wetted underwear layers. Under radiant stress, whole body heat loss decreased, i.e., heat gain occurred compared to the reference. This heat gain increased with radiation intensity, and decreased with air velocity and clothing insulation. Except for the reflective outer layer that showed only minimal heat gain over the whole range of radiation intensities, the influence of the outer garments’ material and colour was small with dry clothing. Wetting the underclothing for simulating sweat accumulation, however, caused differing effects with higher heat gain in less permeable garments.
Źródło:
International Journal of Occupational Safety and Ergonomics; 2010, 16, 2; 231-244
1080-3548
Pojawia się w:
International Journal of Occupational Safety and Ergonomics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
MHD and thermal radiation effects on exponentially accelerated isothermal vertical plate with uniform mass diffusion
Autorzy:
Muthucumaraswamy, R.
Visalakshi, V.
Powiązania:
https://bibliotekanauki.pl/articles/265445.pdf
Data publikacji:
2013
Wydawca:
Uniwersytet Zielonogórski. Oficyna Wydawnicza
Tematy:
promieniowanie
izotermiczność
płyta pionowa
dyfuzja masy
pole magnetyczne
radiation
isothermal
vertical plate
mass diffusion
magnetic field
Opis:
Thermal radiation effects on an unsteady free convective flow of a viscous incompressible flow of a past an exponentially accelerated infinite isothermal vertical plate with uniform mass diffusion in the presence magnetic field are considered. The fluid considered here is a gray, absorbing-emitting radiation but a non-scattering medium. The plate temperature is raised to Tw and the concentration level near the plate is also raised to Cʹw . An exact solution to the dimensionless governing equations is obtained by the Laplace transform method, when the plate is exponentially accelerated with a velocity u= u0 exp(aʹtʹ) in its own plane against gravitational field. The effects of velocity, temperature and concentration fields are studied for different physical parameters such as the magnetic field parameter, thermal radiation parameter, Schmidt number, thermal Grashof number, mass Grashof number and time. It is observed that the velocity increases with decreasing magnetic field parameter or radiation parameter. But the trend is just reversed with respect to a or t .
Źródło:
International Journal of Applied Mechanics and Engineering; 2013, 18, 2; 599-608
1734-4492
2353-9003
Pojawia się w:
International Journal of Applied Mechanics and Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Hydromagnetic rarefied fluid flow over a wedge in the presence of surface slip and thermal radiation
Autorzy:
Das, K.
Sharma, R. P.
Duari, P. R.
Powiązania:
https://bibliotekanauki.pl/articles/264410.pdf
Data publikacji:
2017
Wydawca:
Uniwersytet Zielonogórski. Oficyna Wydawnicza
Tematy:
convective flow
heat transfer
surface slip
magnetic field
thermal radiation
przepływ konwekcyjny
przenoszenie ciepła
pole magnetyczne
promieniowanie cieplne
Opis:
An analysis is presented to investigate the effects of thermal radiation on a convective slip flow of an electrically conducting slightly rarefied fluid, having temperature dependent fluid properties, over a wedge with a thermal jump at the surface of the boundary in the presence of a transverse magnetic field. The reduced equations are solved numerically using the finite difference code that implements the 3-stage Lobatto IIIa formula for the partitioned Runge-Kutta method. Numerical results for the dimensionless velocity and temperature as well as for the skin friction coefficient and the Nusselt number are presented through graphs and tables for pertinent parameters to show interesting aspects of the solution.
Źródło:
International Journal of Applied Mechanics and Engineering; 2017, 22, 4; 827-837
1734-4492
2353-9003
Pojawia się w:
International Journal of Applied Mechanics and Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Combined effects of thermal radiation and Hall current on MHD Casson nanofluid exerted by peristaltic transport
Autorzy:
Asha, S. K.
Hadapad, Chandrashekhar
Powiązania:
https://bibliotekanauki.pl/articles/1193365.pdf
Data publikacji:
2021
Wydawca:
Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
Tematy:
Hall current
MHD
nanofluid
peristaltic transport
thermal radiation
Opis:
The present work intends to analyse the MHD Casson nano fluid inside an asymmetric channel. The equations governing the fluid flow admit both Thermophoresis and Brownian motion alongside thermal radiation. We acquired closed form analytical solutions for temperature, axial velocity, nanoparticle concentration and pressure gradient profiles. The ascendency of governing parameters like thermal radiation parameter, thermophoresis, Brownian, Hartmann number and Hall parameter on dimensionless temperature, concentration and pressure gradient profiles have been explained in detailed manner with the aid of plots and table. The prevailed results in this article are verified with prior available literature for specific cases and they are in good agreement.
Źródło:
World Scientific News; 2021, 155; 1-22
2392-2192
Pojawia się w:
World Scientific News
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effect of thermal radiation and chemical reaction on MHD flow of blood in stretching permeable vessel
Autorzy:
Zigta, B.
Powiązania:
https://bibliotekanauki.pl/articles/1839798.pdf
Data publikacji:
2020
Wydawca:
Uniwersytet Zielonogórski. Oficyna Wydawnicza
Tematy:
rozciąganie
pole magnetyczne
promieniowanie cieplne
reakcja chemiczna
stretching velocity
similarity transformations
time dependent magnetic field intensity
thermal radiation
chemical reaction
Opis:
This paper focuses on the theoretical analysis of blood flow in the presence of thermal radiation and chemical reaction under the influence of time dependent magnetic field intensity. Unsteady non linear partial differential equations of blood flow consider time dependent stretching velocity, the energy equation also accounts time dependent temperature of vessel wall and the concentration equation includes the time dependent blood concentration. The governing non linear partial differential equations of motion, energy and concentration are converted into ordinary differential equations using similarity transformations solved numerically by applying ode45. The effect of physical parameters, viz., the permeability parameter, unsteadiness parameter, Prandtl number, Hartmann number, thermal radiation parameter, chemical reaction parameter and Schmidt number on flow variables, viz., velocity of blood flow in vessel, temperature and concentration of blood, has been analyzed and discussed graphically. From the simulation study the following important results are obtained: velocity of blood flow increases with the increment of both permeability and unsteadiness parameter. The temperature of blood increases at the vessel wall as the Prandtl number and Hartmann number increase. Concentration of blood decreases as time dependent chemical reaction parameter and Schmidt number increases.
Źródło:
International Journal of Applied Mechanics and Engineering; 2020, 25, 3; 198-211
1734-4492
2353-9003
Pojawia się w:
International Journal of Applied Mechanics and Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
MHD slip flow past an extending surface with third type boundary condition and thermal radiation effects
Autorzy:
Gururaj, A. D. M.
Dhanasekaran, S.
Parthiban, V.
Powiązania:
https://bibliotekanauki.pl/articles/265680.pdf
Data publikacji:
2019
Wydawca:
Uniwersytet Zielonogórski. Oficyna Wydawnicza
Tematy:
promieniowanie cieplne
magnetohydrodynamika
warunki graniczne
third type boundary condition
slip flow
thermal radiation
extending surface
Opis:
MHD slip flow past an extending surface with third type (convective) boundary condition and thermal radiation is analysed. The governing momentum and energy equations are converted into set of nonlinear ordinary differential equations using appropriate similarity transformations. The Fourth-Order Runge-Kutta shooting method is applied for obtaining the numerical solution of the resulting nonlinear ordinary differentia equations. The numerical results for velocity and temperature distribution are found for different values of the vital parameters, namely: the magnetic interaction factor, slip factor, convective factor, Prandtl number and radiation factor and are presented graphically, and discussed.
Źródło:
International Journal of Applied Mechanics and Engineering; 2019, 24, 3; 577-590
1734-4492
2353-9003
Pojawia się w:
International Journal of Applied Mechanics and Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Thermal radiation, chemical reaction, viscous and joule dissipation effects on MHD flow embedded in a porous medium
Autorzy:
Zigta, B.
Powiązania:
https://bibliotekanauki.pl/articles/264380.pdf
Data publikacji:
2019
Wydawca:
Uniwersytet Zielonogórski. Oficyna Wydawnicza
Tematy:
promieniowanie cieplne
reakcja chemiczna
porowatość
thermal radiation
chemical reaction
Joule dissipation
viscous dissipation
porous medium
Opis:
An analysis is presented to study the effects of thermal radiation, chemical reaction, viscous and Joule dissipation on MHD free convection flow between a pair of infinite vertical Couette channel walls embedded in a porous medium. The fluid flows by a strong transverse magnetic field imposed perpendicularly to the channel wall on the assumption of a small magnetic Reynolds number. The governing non linear partial differentia equations are transformed in to ordinary differential equations and are solved analytically. The effect of various parameters viz., Eckert number, electric conductivity, dynamic viscosity and strength of magnetic field on temperature profile has been discussed and presented graphically.
Źródło:
International Journal of Applied Mechanics and Engineering; 2019, 24, 3; 725-737
1734-4492
2353-9003
Pojawia się w:
International Journal of Applied Mechanics and Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Conjugate heat and mass transfer on fluctuating mixed convection flow along a vertical wedge with thermal radiation
Autorzy:
Firoza, M. N.
Roy, N. C.
Hossain, A.
Powiązania:
https://bibliotekanauki.pl/articles/264573.pdf
Data publikacji:
2017
Wydawca:
Uniwersytet Zielonogórski. Oficyna Wydawnicza
Tematy:
mixed convection
thermal radiation
vertical wedge
promieniowanie cieplne
przepływ ciepła
niska częstotliwość
Opis:
We study the boundary layer characteristics of heat and mass transfer flow past a vertical wedge in the presence of thermal radiation. The surface temperature and the species concentration are assumed to be oscillating in the magnitude but not in the direction of oncoming flow velocity. The governing equations have been solved by two distinct methods, namely, the straightforward finite difference method for the entire frequency range, and the series solution for the low frequency range and the asymptotic series expansion method for the high frequency range. Numerical solutions have been presented in terms of the amplitudes and phase angles of the skin friction, the rate of heat transfer and the mass transfer with the variations of Richardson’s number, the Prandtl number, the conduction–radiation parameter, the surface temperature parameter and the Schmidt number. Furthermore, the effects of these parameters are examined in terms of the transient skin friction, heat transfer and mass transfer.
Źródło:
International Journal of Applied Mechanics and Engineering; 2017, 22, 3; 539-565
1734-4492
2353-9003
Pojawia się w:
International Journal of Applied Mechanics and Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł

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