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1
Gore, J. P., U. S. Ip, and Y. R. Sivathanu. "Coupled Structure and Radiation Analysis of Acetylene/Air Flames." Journal of Heat Transfer 114, no. 2 (May 1, 1992): 487–93. http://dx.doi.org/10.1115/1.2911299.
Повний текст джерелаАнотація:
A coupled radiation-structure analysis of turbulent, non-premixed, strongly radiating acetylene/air flames is described. The analysis extends the laminar flamelet concept to include the effects of local radiative heat loss/gain. A new method for the calculation of the radiative source term is presented. New measurements of mean and fluctuating emission temperatures and radiation intensities, and previous data concerning flame structure are used to evaluate the predictions. Results show good agreement between measurements and predictions of flame structure similar to past uncoupled calculations. The mean emission temperatures and the mean visible radiation intensities are substantially underpredicted by the uncoupled analysis. The coupled calculations provide reasonable estimates of both quantities.
2
Chiang, Ren-Tai. "Analysis of Radiation Interactions and Biological Effects for Boron Neutron Capture Therapy." ASEAN Journal on Science and Technology for Development 35, no. 3 (December 24, 2018): 203–7. http://dx.doi.org/10.29037/ajstd.535.
Повний текст джерелаАнотація:
The direct and indirect ionizing radiation sources for boron neutron capture therapy (BNCT)are identi?ed. The mechanisms of physical, chemical and biological radiation interactions for BNCT are systematically described and analyzed. The relationship between the effect of biological radiation and radiation dose are illustrated and analyzed for BNCT. If the DNAs in chromosomes are damaged by ion- izing radiations, the instructions that control the cell function and reproduction are also damaged. This radiation damage may be reparable, irreparable, or incorrectly repaired. The irreparable damage can result in cell death at next mitosis while incorrectly repaired damage can result in mutation. Cell death leads to variable degrees of tissue dysfunction, which can affect the whole organism’s functions. Can- cer cells cannot live without oxygen and nutrients via the blood supply. A cancer tumor can be shrunk by damaging angiogenic factors and/or capillaries via ionizing radiations to decrease blood supply into the cancer tumor. The collisions between ionizing radiations and the target nuclei and the absorption of the ultraviolet, visible light, infrared and microwaves from bremsstrahlung in the tumor can heat up and damage cancer cells and function as thermotherapy. The cancer cells are more chemically and biologically sensitive at the BNCT-induced higher temperatures since free-radical-induced chemical re- actions are more random and vigorous at higher temperatures after irradiation, and consequently the cancer cells are harder to divide or even survive due to more cell DNA damage. BNCT is demonstrated via a recent clinical trial that it is quite effective in treating recurrent nasopharyngeal cancer.
3
Vicquelin, R., Y. F. Zhang, O. Gicquel, and J. Taine. "Effects of radiation in turbulent channel flow: analysis of coupled direct numerical simulations." Journal of Fluid Mechanics 753 (July 25, 2014): 360–401. http://dx.doi.org/10.1017/jfm.2014.368.
Повний текст джерелаАнотація:
AbstractThe role of radiative energy transfer in turbulent boundary layers is carefully analysed, focusing on the effect on temperature fluctuations and turbulent heat flux. The study is based on direct numerical simulations (DNS) of channel flows with hot and cold walls coupled to a Monte-Carlo method to compute the field of radiative power. In the conditions studied, the structure of the boundary layers is strongly modified by radiation. Temperature fluctuations and turbulent heat flux are reduced, and new radiative terms appear in their respective balance equations. It is shown that they counteract turbulence production terms. These effects are analysed under different conditions of Reynolds number and wall temperature. It is shown that collapsing of wall-scaled profiles is not efficient when radiation is considered. This drawback is corrected by the introduction of a radiation-based scaling. Finally, the significant impact of radiation on turbulent heat transfer is studied in terms of the turbulent Prandtl number. A model for this quantity, based on the new proposed scaling, is developed and validated.
4
Atashafrooz, M., and SA Gandjalikhan Nassab. "Simulation of three-dimensional laminar forced convection flow of a radiating gas over an inclined backward-facing step in a duct under bleeding condition." Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science 227, no. 2 (May 17, 2012): 332–45. http://dx.doi.org/10.1177/0954406212447657.
Повний текст джерелаАнотація:
This study presents a numerical analysis of three-dimensional laminar forced convection flow of a radiating gas over an inclined backward-facing step in a rectangular duct under bleeding condition. The fluid is treated as a gray, absorbing, emitting, and scattering medium. The three-dimensional Cartesian coordinate system is used to solve the governing equations which are the conservations of mass, momentum, and energy. These equations are solved numerically using the computational fluid dynamic techniques to obtain the temperature and velocity fields, while the blocked-off method is employed to simulate the incline surface. Discretized forms of these equations are obtained by the finite volume method and solved using the SIMPLE algorithm. Since the gas is considered as a radiating medium, besides the convective and conductive terms in the energy equation, the radiative term also presented. For computation of this term, the radiative transfer equation is solved numerically by the discrete ordinates method to find the divergence of radiative heat flux distribution inside the radiating medium. By this numerical procedure, the role of radiation heat transfer on convection flow of a radiating gas which has many engineering applications (for example in heat exchangers and combustion chambers) is studied in detail. Beside, the effects of bleeding coefficient, albedo coefficient, optical thickness, and the radiation–conduction parameter on heat transfer behavior of the system are investigated. Comparison of numerical results with the available data published in the open literature shows a good agreement.
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Damm, David L., and Andrei G. Fedorov. "Spectral Radiative Heat Transfer Analysis of the Planar SOFC." Journal of Fuel Cell Science and Technology 2, no. 4 (April 5, 2005): 258–62. http://dx.doi.org/10.1115/1.2041667.
Повний текст джерелаАнотація:
Thermo-mechanical failure of components in planar-type solid oxide fuel cells (SOFCs) depends strongly on the local temperature gradients at the interfaces of different materials. Therefore, it is of paramount importance to accurately predict the temperature fields within the stack, especially near the interfaces. Because of elevated operating temperatures (of the order of 1000K or even higher), radiation heat transfer could become a dominant mode of heat transfer in the SOFCs. In this study, we extend our recent work on radiative effects in solid oxide fuel cells [J. Power Sources, 124, No. 2, pp. 453–458] by accounting for the spectral dependence of the radiative properties of the electrolyte material. The measurements of spectral radiative properties of the polycrystalline yttria-stabilized zirconia electrolyte we performed indicate that an optically thin approximation can be used for treatment of radiative heat transfer. To this end, the Schuster–Schwartzchild two-flux approximation is used to solve the radiative transfer equation for the spectral radiative heat flux, which is then integrated over the entire spectrum using an N-band approximation to obtain the total heat flux due to thermal radiation. The divergence of the total radiative heat flux is then incorporated as a heat sink into a three-dimensional thermo-fluid model of a SOFC through the user-defined function utility in the commercial FLUENT computational fluid dynamics software. The results of sample calculations are reported and compared against the base line cases when no radiation effects are included and when the spectrally gray approximation is used for treatment of radiative heat transfer.
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Liu, Dalong, Xiaowei Jia, and Wenqin Wang. "Comparative analysis of simulation of urban radiation field." MATEC Web of Conferences 282 (2019): 02026. http://dx.doi.org/10.1051/matecconf/201928202026.
Повний текст джерелаАнотація:
In order to compare the differences between various outdoor environmental simulation software in the urban radiation field, ENVI-met, RayMan and SOLWEIG were selected as the research objects. The multiple types of urban radiation intensities that can be obtained by each software are compared, and the calculation method of types of these radiations was analyzed. Effects of underlying surface on the radiation field were simulated separately. The differences in radiation field performance simulations of three softwares were compared from several aspects such as short wave, direct radiation and reflected radiation. It is found that Rayman has the high sensitivity and fast simulation speed, but the output radiation parameters are less; ENVI-met can calculate the most radiation parameters and calculate the long-short wave radiation heat transfer process between building surfaces; the SOLWEIG can be used for simulation in large outdoor space, and has more calculated radiation parameters, but has large error. All three softwares can calculate the effect of space enclosure on direct and scattered radiation.
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Burleyson, Casey D., Charles N. Long, and Jennifer M. Comstock. "Quantifying Diurnal Cloud Radiative Effects by Cloud Type in the Tropical Western Pacific." Journal of Applied Meteorology and Climatology 54, no. 6 (June 2015): 1297–312. http://dx.doi.org/10.1175/jamc-d-14-0288.1.
Повний текст джерелаАнотація:
AbstractCloud radiative effects are examined using long-term datasets collected at the U.S. Department of Energy’s three Atmospheric Radiation Measurement Program Climate Research Facilities in the tropical western Pacific Ocean. The surface radiation budget, cloud populations, and cloud radiative effects are quantified by partitioning the data by cloud type, time of day, and large-scale modes of variability such as El Niño–Southern Oscillation (ENSO) phase and wet/dry seasons at Darwin, Australia. The novel aspect of this analysis is the breakdown of aggregate cloud radiative effects by cloud type across the diurnal cycle. The Nauru Island (Republic of Nauru) cloud populations and subsequently the surface radiation budget are strongly impacted by ENSO variability, whereas the cloud populations over Manus Island (Papua New Guinea) shift only slightly in response to changes in ENSO phase. The Darwin site exhibits large seasonal monsoon-related variations. When present, deeper convective clouds have a strong influence on the amount of radiation that reaches the surface. Their limited frequency reduces their aggregate radiative impact, however. The largest source of shortwave cloud radiative effects at all three sites comes from low clouds. The observations are used to demonstrate that potential model biases in the amplitude of the diurnal cycle and mean cloud frequency would lead to larger errors in the surface energy budget when compared with biases in the timing of the diurnal cycle of cloud frequency. These results provide solid benchmarks to evaluate model simulations of cloud radiative effects in the tropics.
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Anwar Beg, O., J. Zueco, H. S. Takhar, and T. A. Beg´. "Network Numerical Simulation of Impulsively-Started Transient Radiation-Convection Heat and Mass Transfer in a Saturated Darcy-Forchheimer Porous Medium." Nonlinear Analysis: Modelling and Control 13, no. 3 (July 25, 2008): 281–303. http://dx.doi.org/10.15388/na.2008.13.3.14558.
Повний текст джерелаАнотація:
We study the effects of thermal radiation and porous drag forces on the natural convection heat and mass transfer of a viscous, incompressible, gray, absorbingemmitting fluid flowing past an impulsively started moving vertical plate adjacent to a non-Darcian porous regime. The governing boundary-layer equations are formulated in an (X∗, Y∗, t∗) coordinate system with appropriate boundary conditions. The Rosseland diffusion approximation is employed to analyze the radiative heat flux and is appropriate for non-scattering media. The model is non-dimensionalized and solved with the network simulation model. We study the influence of Prandtl number, radiation-conduction parameter, thermal Grashof number, species Grashof number, Schmidt number, Darcy number and Forchheimer number on the dimensionless velocity, temperature and species function distributions. Additionally we compute the variation of the local skin friction, Nusselt number and Sherwood number for selected thermophysical parameters. Increasing Darcy number is seen to accelerate the flow; the converse is apparent for an increase in Forchheimer number. Thermal radiation is seen to reduce both velocity and temperature in the boundary layer. The interactive effects of second order porous drag and thermal radiation are also considered. The model finds applications in solar energy collection systems, porous combustors, transport in fires in porous media (forest fires) and also the design of high temperature chemical process systems.
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Ayash, Tarek, Sunling Gong, and Charles Q. Jia. "Direct and Indirect Shortwave Radiative Effects of Sea Salt Aerosols." Journal of Climate 21, no. 13 (July 1, 2008): 3207–20. http://dx.doi.org/10.1175/2007jcli2063.1.
Повний текст джерелаАнотація:
Abstract Sea salt aerosols play a dual role in affecting the atmospheric radiative balance. Directly, sea salt particles scatter the incoming solar radiation and absorb the outgoing terrestrial radiation. By acting as cloud condensation nuclei, sea salt aerosols indirectly modulate the atmospheric radiative budget through their effective contribution to cloud formation. Using the Canadian Aerosol Module (CAM)–Canadian Centre for Climate Modelling and Analysis (CCCma) GCM, version 3 (GCM3) framework, the direct as well as the indirect shortwave (SW) radiative effects of sea salt aerosols are simulated. The model results herein suggest that sea salt aerosols exert a significant direct radiative effect over oceanic regions, with seasonal means in the range from −2 to −3 W m−2 over the Southern Ocean. Globally, sea salt’s SW indirect effect (annual mean −0.38 W m−2) is found to be less than its direct effect (annual mean −0.65 W m−2). However, sea salt’s indirect effect is found to be far stronger over the Southern Hemisphere than over the Northern Hemisphere, especially over the Southern Ocean with seasonal means around −4 W m−2, which exceed its direct effect. The model results herein suggest that sea salt aerosols significantly modulate the atmospheric radiation budget over oceanic regions and need to be accounted for in global climate models.
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Zhan, Yueying, Jianhua He, Fei Wang, and Liqian Wang. "Analysis and testing of total ionizing dose effect on several commercial optical transceivers via gamma-ray radiation." Chinese Optics Letters 17, no. 5 (2019): 052302. http://dx.doi.org/10.3788/col201917.052302.
Повний текст джерела
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Myson, Shruthy, and Smita Saklesh Nagouda. "Convective instability analysis of couple-stress dielectric fluid saturated anisotropic porous medium with radiation effect." Multidiscipline Modeling in Materials and Structures 16, no. 5 (March 16, 2020): 1019–39. http://dx.doi.org/10.1108/mmms-08-2019-0149.
Повний текст джерелаАнотація:
PurposeThe effects of anisotropy and radiation cannot be considered negligible while investigating the stability of the fluid in convection. Hence, the purpose of this paper is to analyze how these effects could affect the system while considering a couple-stress dielectric fluid. Therefore, the study establishes the effect of thermal radiation in a couple-stress dielectric fluid with an anisotropic porous medium using Goody's approach (Goody, 1956).Design/methodology/approachTo analyze the effect of radiation on the onset of convection, the Milne–Eddington approximation is employed to convert radiative heat flux to thermal heat flux. The equations are further developed to approximate for transparent and opaque medium. Stability of the quiescent state within the framework of linear theory is performed. The principle of exchange of stabilities is shown to be valid by means of single-term Galerkin method. Large values of conduction–radiation and absorptivity parameters are avoided as fluid is considered as liquid rather than gas.FindingsThe radiative heat transfer effect on a couple-stress dielectric fluid saturated anisotropic porous medium is examined in terms of Milne–Eddington approximation. The effect of couple-stress, dielectric, anisotropy and radiation parameters are analyzed graphically for both transparent and opaque medium. It is observed that the conduction–radiation parameter stabilizes the system; in addition, the critical Darcy–Rayleigh number also shows a stabilizing effect in the absence of couple-stress, dielectric and anisotropy parameters, for both transparent and opaque medium. Furthermore, the absorptivity parameter stabilizes the system in the transparent medium, whereas it exhibits a dual effect in the case of an opaque medium. It was also found that an increase in thermal and mechanical anisotropy parameters shows an increase in the cell size, whereas the increase in Darcy–Roberts number and conduction–radiation parameter decreases the cell size. The validity of principle of exchange of stability is performed and concluded that marginal stability is the preferred mode than oscillatory.Originality/valueThe effects of anisotropy and radiation on Rayleigh–Bénard convection by considering a couple-stress dielectric fluid has been analyzed for the first time.
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Izadpanah, E., S. Talebi, and M. H. Hekmat. "Numerical simulation of non-Fourier effects in combined heat transfer." Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science 225, no. 2 (June 23, 2010): 429–36. http://dx.doi.org/10.1243/09544062jmes2001.
Повний текст джерелаАнотація:
The non-Fourier effects on transient and steady temperature distribution in combined heat transfer are studied. The processes of coupled conduction and radiation heat transfer in grey, absorbing, emitting, scattering, one-dimensional medium with black boundary surfaces are analysed numerically. The hyperbolic heat conduction equation is solved by flux splitting method, and the radiative transfer equation is solved by P1 approximate method. The transient thermal responses obtained from non-Fourier heat conduction equation are compared with those obtained from the Fourier heat conduction equation. The results show that the non-Fourier effect can be important when the conduction to radiation parameter and the thermal relaxation time are larger. Further, the radiation effect is more pronounced at small values of single scattering albedo and conduction to radiation parameters. Analysis results indicate that the internal radiation in the medium significantly influences the wave nature.
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Alessa, Nazek. "Transformation Magnetohydrodynamics in Presence of a Channel Filled with Porous Medium and Heat Transfer of Non-Newtonian Fluid by Using Lie Group Transformations." Journal of Function Spaces 2020 (October 22, 2020): 1–6. http://dx.doi.org/10.1155/2020/8840287.
Повний текст джерелаАнотація:
In this paper, the numerical results are presented by using Lie group transformations, to be more efficient and sophisticated. To solve various fluid dynamic problems numerically, we present the numerical results in a field of velocity and distribution of temperature for different parameters regarding the problem of radiative heat, a magnetohydrodynamics, and non-Newtonian viscoelasticity for the unstable flow of optically thin fluid inside a channel filled with nonuniform wall temperature and saturated porous medium, including Hartmann number, porous medium and frequency parameter, and radiation parameter, with a comparison of the corresponding flow problems for a Newtonian fluid. Moreover, the effects of the pertinent parameters on the friction coefficient of skin and local Nusselt number were discussed numerically and also illustrate that graphically.
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Mahila, S., PR Devaki, and P. Sai Kumar. "Effect of Wi-Fi radiation on Salivary Cortisol levels." Biomedicine 39, no. 1 (November 14, 2020): 52–58. http://dx.doi.org/10.51248/.v39i1.221.
Повний текст джерелаАнотація:
Introduction and Aim: Sensitivity to electromagnetic radiation is the emerging health problem of the 21st century. The sensitivity to electromagnetic radiations has become the major issue to be highlighted as environmental intolerance to Wi-Fi. These Wi-Fi radiations are a form of stress and thereby tend to increase salivary cortisol levels. Hence this study was done to analyse the effect of Wi-Fi radiations on salivary cortisol levels. The aim of the present study is to study the effect of Wi-Fi radiation from mobile phone towers on salivary cortisol levels.
Materials and Methods: This study incorporated analysis of salivary cortisol levels in 72 healthy volunteers who were divided into two groups, subjects residing within 100 mts of the location of mobile phone towers and subjects who were residing outside 100 mts of the location of mobile phone towers and both groups were age & sex matched. The data was statistically analysed using the ANOVA with the SPSS software15.0 version.
Results: The study showed that the salivary cortisol level increased in those subjects staying within 100 meters of the location of mobile phone towers compared to the subjects residing outside 100 mts of the location of mobile phone towers. Conclusion: From this study, it is concluded that Wi-Fi radiation causes invisible damaging effects by increasing the levels of salivary cortisol and vigorous measures to be taken to safeguard ourselves from these radiations.
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D, Basandrai, Dhami A. K, and Bedi A. K. "NONTHERMAL EFFECTS OF MOBILE PHONE RADIATIONS ON HUMAN HEART RATE, BLOOD PRESSURE, AND SUGAR LEVEL." Asian Journal of Pharmaceutical and Clinical Research 10, no. 7 (July 1, 2017): 142. http://dx.doi.org/10.22159/ajpcr.2017.v10i7.17655.
Повний текст джерелаАнотація:
Objective: A single-blinded pilot study has been conducted to investigate the effect of cell phone radiation on the human heart. Methods: Experimental work has been conducted in Jalandhar-based hospital under the supervision of a cardiologist. During experimental work, electrocardiogram (ECG), blood pressure (BP) level, and sugar level have been examined before and after cell phone radiation exposure. For ECG analysis, the parameters such as heart rate, rhythm, mechanism, axis, P wave, PR interval, QRS complex, ST segment, T wave, and QT interval have been examined in the study.Results: No significant variations in the results of above-mentioned parameter has been observed before and after acute exposure of cell phones radiations by placing cell phone closer to heart.Conclusion: The result of this study concludes that mobile phone radiations do not interfere with any electrical activity of the human heart, BP, and sugar level in healthy individuals.
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Rosida, NFN, and Indah Susanti. "PENGARUH AEROSOL TERHADAP FLUKS RADIASI NETO DI LAPISAN ATAS ATMOSFER DAN DI PERMUKAAN BERDASAR DATA SATELIT [INFLUENCE OF AEROSOL ON NET RADIATION FLUX AT THE TOP OF ATMOSPHERE AND SURFACE BASED ON SATELLITE]." Jurnal Sains Dirgantara 14, no. 2 (July 21, 2017): 27. http://dx.doi.org/10.30536/j.jsd.2016.v14.a2444.
Повний текст джерелаАнотація:
The direct effects of aerosols on radiation budget in Indonesia have been analyzed based on radiation flux net data from the Clouds and the Earth's Radiant Energy System (CERES) instrument and aerosol optical depth (AOD) from the Moderate Resolution Imaging Spectroradiometer (MODIS) Terra. Radiation budget calculated including short wave and long-wave radiation. Data from March 2000 until February 2010, processed using Grads version 2 to obtain aerosol radiative forcing value. Net radiation in clean sky, estimated using slope method. The analysis showed high temporal variation of aerosols density in the atmosphere with a value AODmax> 2, which generally causes decreases net radiation flux, so providing a cooling effect. The influence of aerosols on the net radiation flux can be very clearly seen in the case of forest fires. AOD in 2006 increased and caused radiation flux anomalies ranging from -9 watt/m-2 to -14 watts/m-2, with the largest decline occurred in the surface. From all the data period, aerosol radiative forcing at TOA level (ARFTOA) on Indonesia was -0.49 watt/m-2 and aerosol radiative forcing at the surface level (ARFSurf) on Indonesia was -17.72 watt/m-2, that influence to the Indonesian climate condition.
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Ungureanu, Loredana, Luciana Cristea, Marina Bulmaga, and Diana Cazangiu. "The Analysis of the Influence of EMR Effects Provided From the Mobile Phones with Different SAR Index." Applied Mechanics and Materials 555 (June 2014): 446–51. http://dx.doi.org/10.4028/www.scientific.net/amm.555.446.
Повний текст джерелаАнотація:
The researches realized on the biological effects of Electromagnetic Radiation (EMR) highlighted that the exposure of the human factor on the electromagnetic radiations of high frequency determines an excessive heating of the tissue causing different burning types. The aim of this paper is to analyze, by comparison, the effect of heating of the facial tissue under the Electromagnetic Radiation (EMR) influence provided from two mobile phones with different Specific Absorption Rate (SAR) index. Helping with the thermal maps, it determined the heating level of the human tissue exposed under the EMR generated by the phone during the conversation. The results obtained after the analysis are very useful for the evaluation of the heating level of the facial tissue in function of the SAR absorption index of the phone
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AZIZ, Jabir. "Analysis of Biological Effects of Microwave Energy and Safe Distance Calculations." Journal of Al-Rafidain University College For Sciences ( Print ISSN: 1681-6870 ,Online ISSN: 2790-2293 ), no. 2 (October 24, 2021): 1–14. http://dx.doi.org/10.55562/jrucs.v25i2.435.
Повний текст джерелаАнотація:
Microwave energy has found wide range of applications in the fields of communications, industrial, scientific, medical, commercial and military. In the Public applications, microwave energy may produce biological effects which may sometimes, lead to adverse health effect.This paper introduces the relationship between microwave energy and the public health through the analysis of the effects of microwave energy on the biological systems and its hazardous effects on the health of the human body. It starts with the analysis of non-thermal and thermal effects of microwave energy on the tissue of the human body, and then it gives an analysis of the radiation limits of microwave radiation hazard and the different international standards. The safe distance from the radiating source was formulated and estimated for four scenarios, which represents different case studies (On-Beam-Axis of Continuous Transmission, On-Beam-Axis of Pulsating Transmission, Side-Lobe Transmission, and Rotating-Beam Transmission).The results of these estimations indicate that there is a hazardous distance varies from few meters up to few hundred of meters depending on the coverage, power and type of transmission.
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Bita, Bogdan, Elena Stancu, Daniela Stroe, Mirabela Dumitrache, Steluta Carmen Ciobanu, Simona Liliana Iconaru, Daniela Predoi, and Andreea Groza. "The Effects of Electron Beam Irradiation on the Morphological and Physicochemical Properties of Magnesium-Doped Hydroxyapatite/Chitosan Composite Coatings." Polymers 14, no. 3 (January 31, 2022): 582. http://dx.doi.org/10.3390/polym14030582.
Повний текст джерелаАнотація:
This work reports on the influence of 5 MeV electron beam radiations on the morphological features and chemical structure of magnesium-doped hydroxyapatite/chitosan composite coatings generated by the magnetron sputtering technique. The exposure to ionizing radiation in a linear electron accelerator dedicated to medical use has been performed in a controllable manner by delivering up to 50 Gy radiation dose in fractions of 2 Gy radiation dose per 40 s. After the irradiation with electron beams, the surface of layers became nano-size structured. The partial detachment of irradiated layers from the substrates has been revealed only after visualizing their cross sections by scanning electron microscopy. The energy dispersive X-ray spectral analysis of layer cross-sections indicated that the distribution of chemical elements in the samples depends on the radiation dose. The X-ray photoelectron spectroscopy, Fourier transform infrared spectroscopy and X-ray diffraction analysis have shown that the physicochemical processes induced by the ionizing radiation in the magnesium doped hydroxyapatite/chitosan composite coatings do not alter the apatite structure, and Mg remains bonded with the phosphate groups.
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Chen, Guoxing, Wei-Chyung Wang, and Jen-Ping Chen. "Aerosol–Stratocumulus–Radiation Interactions over the Southeast Pacific." Journal of the Atmospheric Sciences 72, no. 7 (July 2015): 2612–21. http://dx.doi.org/10.1175/jas-d-14-0319.1.
Повний текст джерелаАнотація:
Atmosphere–ocean general circulation models tend to underestimate the solar radiative forcing by stratocumulus over the southeast Pacific, contributing to a warm sea surface temperature (SST) bias. The underestimation may be caused by biases in either macro- or micro- (or both) physical properties of clouds. This study used the WRF Model (incorporated with a physics-based two-moment cloud microphysical scheme) together with the 2008 Variability of the American Monsoon Systems Ocean–Cloud–Atmosphere–Land Study (VOCALS) field observations to investigate the effects of anthropogenic aerosols on the stratocumulus properties and their subsequent effects on the surface radiation balance. The effects were studied by comparing two cases: a control case with the anthropogenic aerosols and a sensitivity case without the anthropogenic aerosols. Results show that the control case produced cloud properties comparable with the measurements by aircraft and that aerosol–cloud microphysical interactions play an important role in regulating solar cloud radiative forcing. As expected, the anthropogenic aerosols increase the cloud droplet number and decrease the cloud droplet size, resulting in an enhancement of solar cloud radiative forcing and a reduction in solar radiation reaching the sea surface, up to a maximum of about 30 W m−2 near the coast. Results also show that aerosol–cloud microphysics–radiation interactions are sensitive to cloud fraction, thus highlighting the role of cloud diurnal variation in studying the cloud–radiation interactions. Analysis of the high-resolution (3 km) model simulations reveals that there exists an inherent scale dependence of aerosol–cloud–radiation interactions, with coarser horizontal resolution yielding a weaker variability.
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Atalla, Noureddine, and Alain Berry. "Acoustic Radiation from a Coupled Planar Semi-Complex Structure in Heavy Fluid." Journal of Ship Research 38, no. 03 (September 1, 1994): 213–24. http://dx.doi.org/10.5957/jsr.1994.38.3.213.
Повний текст джерелаАнотація:
A mathematical model is derived to address the vibrations and sound radiation into a dense fluid, of a coupled system consisting of two semi-complex plates (i.e., supporting added mass, stiffeners, and having arbitrary elastic boundary conditions) linked in four points through multistage suspensions elements. The supporting plate is subjected to point, line or surface harmonic excitation, while the radiating plate is excited through the suspensions. Both plates are assumed to be baffled, and the radiating plate is fluid loaded. The model is based on a variational approach for the plates, and a matrix transfer approach is used to handle the coupling between the two-plates. The solution is found using a Rayleigh-Ritz expansion in terms of polynomial trial functions which are shown to allow for the arbitrary elastic boundary conditions and to facilitate the calculation of the radiation impedance matrix. The vibrations and noise design of the system is discussed. The main design indicators are the force transmissibilities between the different excitation and attachment points, the mean square velocity, the radiated power and the radiation efficiency of the radiating plate. Numerical examples are presented to show the effects of fluid loading and different design parameters (plates thickness, boundary conditions, added mass, stiffeners, etc.) on the radiated sound.
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Reed, S. J. B. "Fluorescence effects in quantitative microprobe analysis." Proceedings, annual meeting, Electron Microscopy Society of America 48, no. 2 (August 12, 1990): 188–89. http://dx.doi.org/10.1017/s0424820100134533.
Повний текст джерелаАнотація:
Characteristic fluorescenceThe theory of characteristic fluorescence corrections was first developed by Castaing. The same approach, with an improved expression for the relative primary x-ray intensities of the exciting and excited elements, was used by Reed, who also introduced some simplifications, which may be summarized as follows (with reference to K-K fluorescence, i.e. K radiation of element ‘B’ exciting K radiation of ‘A’):1.The exciting radiation is assumed to be monochromatic, consisting of the Kα line only (neglecting the Kβ line).2.Various parameters are lumped together in a single tabulated function J(A), which is assumed to be independent of B.3.For calculating the absorption of the emerging fluorescent radiation, the depth distribution of the primary radiation B is represented by a simple exponential.These approximations may no longer be justifiable given the much greater computing power now available. For example, the contribution of the Kβ line can easily be calculated separately.
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Bailey, Roger C., and Daryl L. Cross. "THE RADIATING EFFECTS OF A PERSON'S RELIGIOUSNESS'." Social Behavior and Personality: an international journal 18, no. 2 (January 1, 1990): 201–5. http://dx.doi.org/10.2224/sbp.1990.18.2.201.
Повний текст джерелаАнотація:
Previous research has indicated that physical attractiveness can “radiate” or spill over onto an interaction partner. This study examined the possible radiating effect of a newly discovered social stereotype, religiousness. Males (N=56) and females (N=119) college students initially rated the religiousness of a male target and then each subject read one of five scenarios describing the male's dating partner's religious background. The female's religious background was described in four ways: 1) Always religious, 2) Recent religious convert, 3) Recent religious heretic, 4) Never religious, and a fifth control condition which omitted information on the female's religious background. Following presentation of the scenarios, subjects again rated the boyfriend's religiousness. Analysis of pre- vs. post- scenario change scores indicated the boyfriend's religiousness increased following knowledge of the girlfriend's long-term or recent religious involvement (positive radiation effect) but decreased following knowledge of the girlfriend's long-term or recent nonreligious involvement (negative radiation effect). It was concluded that the radiation effects identified can serve to further expand our understanding of the interpersonal perceptions people hold of the religious and nonreligious.
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Rehman, Khalil Ur, Wasfi Shatanawi, and Andaç Batur Çolak. "Levenberg–Marquardt Training Technique Analysis of Thermally Radiative and Chemically Reactive Stagnation Point Flow of Non-Newtonian Fluid with Temperature Dependent Thermal Conductivity." Mathematics 11, no. 3 (February 2, 2023): 753. http://dx.doi.org/10.3390/math11030753.
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We have examined the magnetized stagnation point flow of non-Newtonian fluid towards an inclined cylindrical surface. The mixed convection, thermal radiation, viscous dissipation, heat generation, first-order chemical reaction, and temperature-dependent thermal conductivity are the physical effects being carried for better novelty. Mathematical equations are constructed for four different flow regimes. The shooting method is used to evaluate the heat transfer coefficient at the cylindrical surface with and without heat generation/thermal radiation effects. For better examination, we have constructed artificial neural networking models with the aid of the Levenberg–Marquardt training technique and Purelin and Tan-Sig transfer functions. The Nusselt number strength is greater for fluctuations in the Casson fluid parameter, Prandtl number, heat generation, curvature, and Eckert number when thermal radiations are present.
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GHOSH, S., R. FRIEDRICH, M. PFITZNER, CHR STEMMER, B. CUENOT, and M. EL HAFI. "Effects of radiative heat transfer on the structure of turbulent supersonic channel flow." Journal of Fluid Mechanics 677 (April 15, 2011): 417–44. http://dx.doi.org/10.1017/jfm.2011.92.
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The interaction between turbulence in a minimal supersonic channel and radiative heat transfer is studied using large-eddy simulation. The working fluid is pure water vapour with temperature-dependent specific heats and molecular transport coefficients. Its line spectra properties are represented with a statistical narrow-band correlated-k model. A grey gas model is also tested. The parallel no-slip channel walls are treated as black surfaces concerning thermal radiation and are kept at a constant temperature of 1000 K. Simulations have been performed for different optical thicknesses (based on the Planck mean absorption coefficient) and different Mach numbers. Results for the mean flow variables, Reynolds stresses and certain terms of their transport equations indicate that thermal radiation effects counteract compressibility (Mach number) effects. An analysis of the total energy balance reveals the importance of radiative heat transfer, compared to the turbulent and mean molecular heat transport.
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Kwon, You Jin, and Dong Kun Lee. "Thermal Comfort and Longwave Radiation over Time in Urban Residential Complexes." Sustainability 11, no. 8 (April 15, 2019): 2251. http://dx.doi.org/10.3390/su11082251.
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Large cities with a high concentration of high-rise buildings are shaded by urban canyon. This brings a cooling effect compared to the space exposed to the sun, but is not always cool due to the longwave radiation emitted from buildings and the built environment. We tested the micro-scale effects of major external spatial factors, trees, and buildings, under shade on longwave radiation shifts to understand the effects of large shaded areas in megacities. Incoming and outgoing longwave radiations (ILR and OLR, respectively) were found to decrease the overall observation by time zone. Longwave radiation on a micro-scale was also inversely proportional to the tree volume. From mean radiant temperature (MRT) analysis, we found that about a 10% decrease in MRT could be achieved by increasing tree volume by around 50%. Larger tree volumes corresponded to greater blocking effects on longwave radiation. Considering the tree volume, a multilayer urban tree canopy composition can more favorably improve the thermal environment and energy sustainability of a city compared to a single-layer canopy. Larger trees planted with harmonious shrubs are the most effective in reducing longwave radiation.
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Myhre, Gunnar, Bjørn H. Samset, Christian W. Mohr, Kari Alterskjær, Yves Balkanski, Nicolas Bellouin, Mian Chin, et al. "Cloudy-sky contributions to the direct aerosol effect." Atmospheric Chemistry and Physics 20, no. 14 (July 27, 2020): 8855–65. http://dx.doi.org/10.5194/acp-20-8855-2020.
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Abstract. The radiative forcing of the aerosol–radiation interaction can be decomposed into clear-sky and cloudy-sky portions. Two sets of multi-model simulations within Aerosol Comparisons between Observations and Models (AeroCom), combined with observational methods, and the time evolution of aerosol emissions over the industrial era show that the contribution from cloudy-sky regions is likely weak. A mean of the simulations considered is 0.01±0.1 W m−2. Multivariate data analysis of results from AeroCom Phase II shows that many factors influence the strength of the cloudy-sky contribution to the forcing of the aerosol–radiation interaction. Overall, single-scattering albedo of anthropogenic aerosols and the interaction of aerosols with the short-wave cloud radiative effects are found to be important factors. A more dedicated focus on the contribution from the cloud-free and cloud-covered sky fraction, respectively, to the aerosol–radiation interaction will benefit the quantification of the radiative forcing and its uncertainty range.
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Ndlovu, Partner L., and Raseelo J. Moitsheki. "Analysis of a Convective-Radiative Continuously Moving Fin with Temperature-Dependent Thermal Conductivity." International Journal of Nonlinear Sciences and Numerical Simulation 21, no. 3-4 (May 26, 2020): 379–88. http://dx.doi.org/10.1515/ijnsns-2018-0206.
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AbstractIn this article, the differential transform method (DTM) is used to solve the nonlinear boundary value problems describing heat transfer in continuously moving fins undergoing convective-radiative heat dissipation. The thermal conductivity is variable and temperature dependent. The surface of the moving fin is assumed to be gray with a constant emissivity ɛ. The flow in the surrounding medium provides a constant heat transfer coefficient h over the entire surface of the moving fins. The effects of some physical parameters such as the Peclet number, Pe, thermal conductivity parameter, β, convection-conduction parameter, Nc, radiation-conduction parameter, Nr, and dimensionless convection-radiation sink temperature, θa, on the temperature distribution are illustrated and explained.
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Jeong, S. H., and M. Y. Ha. "Computer Modeling of the Continuous Annealing Furnace." Journal of Energy Resources Technology 114, no. 4 (December 1, 1992): 345–50. http://dx.doi.org/10.1115/1.2905963.
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A computer program to calculate the strip temperature heated in the continuous annealing furnace was developed, using the zone method for radiative heat transfer analysis with the measured gas temperature in the furnace. Using the FE operator, the present study considered the effects of soot and transient species in addition to the H2O-CO2 gas mixture on the gas radiative heat transfer. The predicted strip temperature distribution for FE = 1.05 represented well the measured data. The maximum difference in the heat flux transfered to the strip from the combustion gas for FE = 1.0 (without soot and transient species gas radiation) and 1.05 (with soot and transient species gas radiation) was about 15 percent. The present study also investigated the effects of line speed and thickness variations on the strip temperature, establishing the bases for the on-line computer model.
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Stary, O. "EFFECT OF NORMALIZING HEATING OF FERRITE COMPACTS ON COMPACTION DURING RADIATION-THERMAL SINTERING." Eurasian Physical Technical Journal 18, no. 3 (37) (September 24, 2021): 11–14. http://dx.doi.org/10.31489/2021no3/11-14.
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The study investigated linear shrinkage of lithium-titanium ferrite samples during radiation-thermal and thermal sintering. Prior to compaction, part of the powders were subjected to thermal heating for 2h at temperatures of 1273, 1373, and 1473 K. It is found that changes in the shrinkage kinetics of ferrites after powder annealing are consistent with the classical concepts of thermal deexcitation of powders due to annealing of defects. Such defects were formed in powder grains during grinding. The obtained data analysis allowed us to offer the most likely model for radiation-thermal activation of powder ferrite sintering. This is a model of radiation inhibition of non-equilibrium defects relaxation.
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Dufourcq-Sekatcheff, Elizabeth, Stephan Cuiné, Yonghua Li-Beisson, Loïc Quevarec, Myriam Richaud, Simon Galas, and Sandrine Frelon. "Deciphering Differential Life Stage Radioinduced Reproductive Decline in Caenorhabditis elegans through Lipid Analysis." International Journal of Molecular Sciences 22, no. 19 (September 24, 2021): 10277. http://dx.doi.org/10.3390/ijms221910277.
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Wildlife is chronically exposed to various sources of ionizing radiations, both environmental or anthropic, due to nuclear energy use, which can induce several defects in organisms. In invertebrates, reproduction, which directly impacts population dynamics, has been found to be the most radiosensitive endpoint. Understanding the underlying molecular pathways inducing this reproduction decrease can help in predicting the effects at larger scales (i.e., population). In this study, we used a life stage dependent approach in order to better understand the molecular determinants of reproduction decrease in the roundworm C. elegans. Worms were chronically exposed to 50 mGy·h−1 external gamma ionizing radiations throughout different developmental periods (namely embryogenesis, gametogenesis, and full development). Then, in addition to reproduction parameters, we performed a wide analysis of lipids (different class and fatty acid via FAMES), which are both important signaling molecules for reproduction and molecular targets of oxidative stress. Our results showed that reproductive defects are life stage dependent, that lipids are differently misregulated according to the considered exposure (e.g., upon embryogenesis and full development) and do not fully explain radiation induced reproductive defects. Finally, our results enable us to propose a conceptual model of lipid signaling after radiation stress in which both the soma and the germline participate.
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Zare, Mehdi, and Sadegh Sadeghi. "Development of hybrid method for coupled conduction-radiation heat transfer in two-dimensional irregular enclosure considering thermo-radiative effects and varying thermal conductivity." International Journal of Numerical Methods for Heat & Fluid Flow 30, no. 4 (April 19, 2019): 1815–37. http://dx.doi.org/10.1108/hff-11-2018-0667.
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Purpose This study aims to perform a comprehensive investigation to model the thermal characteristics of a coupled conduction-radiation heat transfer in a two-dimensional irregular enclosure including a triangular-shaped heat source. Design/methodology/approach For this purpose, a promising hybrid technique based on the concepts of blocked-off method, FVM and DOM is developed. The enclosure consists of several horizontal, vertical and oblique walls, and thermal conductivity within the enclosure varies directly with temperature and indirectly with position. To simplify the complex geometry, a promising mathematical model is introduced using blocked-off method. Emitting, absorbing and non-isotropic scattering gray are assumed as the main radiative characteristics of the steady medium. Findings DOM and FVM are, respectively, applied for solving radiative transfer equation (RTE) and the energy equation, which includes conduction, radiation and heat source terms. The temperature and heat flux distributions are calculated inside the enclosure. For validation, results are compared with previous data reported in the literature under the same conditions. Results and comparisons show that this approach is highly efficient and reliable for complex geometries with coupled conduction-radiation heat transfer. Finally, the effects of thermo-radiative parameters including surface emissivity, extinction coefficient, scattering albedo, asymmetry factor and conduction-radiation parameter on temperature and heat flux distributions are studied. Originality/value In this paper, a hybrid numerical method is used to analyze coupled conduction-radiation heat transfer in an irregular geometry. Varying thermal conductivity is included in this analysis. By applying the method, results obtained for temperature and heat flux distributions are presented and also validated by the data provided by several previous papers.
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Krishnamurthy, Saranya, Ramani Kannan, Faidhi F. A. Mohamad, Muhamad S. Ahmad, and Yusof Abdullah. "Total-dose Effects on Power MOSFET in SEPIC Converter for Nanosatellite Applications." Recent Advances in Electrical & Electronic Engineering (Formerly Recent Patents on Electrical & Electronic Engineering) 13, no. 5 (September 22, 2020): 758–65. http://dx.doi.org/10.2174/2352096512666191004154951.
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Background: Power converters used in nanosatellite application required to be more tolerant to radiations including proton, electron and heavy-ion radiation. Methods: A Single-Ended Primary Inductance Converter (SEPIC) is selected for the nanosatellite application because of the availability to step up and down the input voltage as well as having a non-inverting polarity between the input and output voltage. In this paper, remodeled SEPIC converter proposed with an improved performance at radiation environment to work for nanosatellite application. In addition, the analysis is carried out for the irradiated power MOSFET in SEPIC converter to check its impact on converter behavior. Results: Experiments conducted with the help of power MOSFET switch used in converter, irradiated with Cobalt60 gamma ray dose level from 50krad to 300krad and output characteristics analyzed by chancing the duty cycle of converter. Investigations shown that conventional converter output characteristics were virtually constant from 10% to 60% duty cycle when different radiated MOSFETs used in the converter. Conclusion: The electrical characteristics started to fluctuate at 60% duty cycle and onwards, while the remodeled converter circuit was less distorted when increasing the radiation dose.
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Marquardt Collow, Allison B., and Mark A. Miller. "The Seasonal Cycle of the Radiation Budget and Cloud Radiative Effect in the Amazon Rain Forest of Brazil." Journal of Climate 29, no. 21 (October 6, 2016): 7703–22. http://dx.doi.org/10.1175/jcli-d-16-0089.1.
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Abstract Changes in the climate system of the Amazon rain forest of Brazil can impact factors that influence the radiation budget such as clouds, atmospheric moisture, and the surface albedo. This study examines the relationships between clouds and radiation in this region using surface observations from the first year of the deployment of the Atmospheric Radiation Measurement (ARM) Program’s Mobile Facility 1 (AMF1) in Manacapuru, Brazil, and satellite measurements from the Clouds and the Earth’s Radiant Energy System (CERES). The seasonal cycles of the radiation budget and cloud radiative effects (CREs) are evaluated at the top of the atmosphere (TOA), at the surface, and within the atmospheric column using these observations and are placed into a regional context using the Modern-Era Retrospective Analysis for Research and Applications, version 2 (MERRA-2). Water vapor and clouds are abundant throughout the year, even though slight decreases are observed in the dry season. The column water vapor load is large enough that the longwave radiative flux divergence is nearly constant throughout the year. Clouds produce a significant shortwave CRE at the surface and TOA, exceeding 200 W m−2 during the wet season. Discrepancies, especially in column shortwave radiative absorption, between the observations and MERRA-2 are demonstrated that warrant additional analysis of the microphysical and macrophysical cloud properties in MERRA-2. More trustworthy fields in the MERRA-2 product suggest that the expansive nearby river system impacts the regional radiation budget and thereby renders AMF1 observations potentially biased relative to regions farther removed from rivers within the Amazon rain forest.
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Pathak, P. P., Vijay Kumar, and R. P. Vats. "Environment condition around transmission towers not fit for livelihood." Environment Conservation Journal 4, no. 1-3 (December 22, 2003): 79–82. http://dx.doi.org/10.36953/ecj.2003.0412311.
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Influence of radio frequency (RF) and mircowave radiation on human body is studied. According to Rai (1992) radio and T.V. transmission towers of Varanasi, which are located in thickly populated area, are causing health hazards problems to the people. Theoretical analysis shows that a transmission tower of 10 kW is expected to cause harmful effects on the people living upto about 300 m. For low power transmitters the distance is smaller. The radiation is more hazardous if a high voltage power transmission line is also passing over the area, as the combined effect of the two radiations may cause cancer risk to the people (Tenferde 1996).
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Goodhead, Dudley T. "Radiation effects in living cells." Canadian Journal of Physics 68, no. 9 (September 1, 1990): 872–86. http://dx.doi.org/10.1139/p90-125.
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Insult from ionizing radiation is in the form of microscopic tracks that are highly structured from the atomic level upwards. The internal composition of mammalian cells, too, is highly structured, from dimensions smaller than the DNA molecule (diameter ~2 nm) up to the entire cell [Formula: see text]. There is a wide spectrum of initial physical and chemical damage, subsequent biochemical modification, and final cellular response. The vast majority of the physical, chemical, and biochemical damage is apparently of little relevance to final observable cellular effects. This predominance of "irrelevant" damage masks the nature of that which is of prime relevance. Nevertheless, systematic studies of the effects of radiations on cells have revealed that there are unifying features in the observed responses of different cell types to induction of different effects, and by different radiations. This implies that there are dominant mechanisms that are open to kinetic analysis. Relevant processes may be dominated by the non-linear kinetics of clusters of ionizations and excitations that are within the macromolecule of interest (DNA) or shared with closely adjacent bound molecules. Quantitative models of radiobiological action have concentrated on the relative kinetics of single-track versus multitrack modes and describe the elementary damage either in terms of single ionizations or of clusters of energy depositions.
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Fraga, G. C., A. P. Petry, and F. H. R. França. "ANALYSIS OF THE TURBULENCE-RADIATION INTERACTION IN A METHANE-AIR DIFFUSION FLAME." Revista de Engenharia Térmica 17, no. 1 (June 30, 2018): 86. http://dx.doi.org/10.5380/reterm.v17i1.62265.
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The phenomenon of turbulence-radiation interaction (TRI) has been demonstrated experimentally, theoretically and numerically to be important in a great number of engineering applications. This paper presents a numerical study on the subject, focusing on a methane-air diffusion flame confined in a rectangular enclosure. An open source, Fortran-based code, Fire Dynamics Simulator, is used for the analysis. Large Eddy Simulation (LES) is adopted to model the turbulence, and to resolve the sub-grid scale terms the dynamic Smagorinsky model is employed. To solve the radiative heat transfer, the finite volume method is used alongside the Weighted-Sum-of-Gray-Gases model. The main objective of the present work is to assess the magnitude of TRI effects for the configuration proposed. For this purpose, the time-averaged wall heat fluxes and volumetric radiative heat source, calculated from the LES results, are compared with those same quantities obtained by independent simulations initialized using mean temperature and species concentration fields. TRI effects are found to be responsible for differences up to 30% between results considering and neglecting turbulent fluctuations. These differences are larger for the radiative heat source and for the radiative heat flux to the walls, smaller for the total heat flux, and almost negligible for the convective heat flux. The influence of the fuel stream Reynolds number on the TRI effects is also evaluated, and a slight decrease on the magnitude of TRI is observed with the increase of that parameter.
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Rana, Sohel, Harish Subbaraman, Austin Fleming, and Nirmala Kandadai. "Numerical Analysis of Radiation Effects on Fiber Optic Sensors." Sensors 21, no. 12 (June 15, 2021): 4111. http://dx.doi.org/10.3390/s21124111.
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Optical fiber sensors (OFS) are a potential candidate for monitoring physical parameters in nuclear environments. However, under an irradiation field the optical response of the OFS is modified via three primary mechanisms: (i) radiation-induced attenuation (RIA), (ii) radiation-induced emission (RIE), and (iii) radiation-induced compaction (RIC). For resonance-based sensors, RIC plays a significant role in modifying their performance characteristics. In this paper, we numerically investigate independently the effects of RIC and RIA on three types of OFS widely considered for radiation environments: fiber Bragg grating (FBG), long-period grating (LPG), and Fabry-Perot (F-P) sensors. In our RIC modeling, experimentally calculated refractive index (RI) changes due to low-dose radiation are extrapolated using a power law to calculate density changes at high doses. The changes in RI and length are subsequently calculated using the Lorentz–Lorenz relation and an established empirical equation, respectively. The effects of both the change in the RI and length contraction on OFS are modeled for both low and high doses using FIMMWAVE, a commercially available vectorial mode solver. An in-depth understanding of how radiation affects OFS may reveal various potential OFS applications in several types of radiation environments, such as nuclear reactors or in space.
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Kozyukov, Aleksandr, Pavel Chubunov, Konstantin Zolnikov, Tatyana Skvortsova, and I. Zhuravleva. "Analysis of potential ECB effects from AI CP exposure." Modeling of systems and processes 14, no. 2 (July 26, 2021): 80–86. http://dx.doi.org/10.12737/2219-0767-2021-14-2-80-86.
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The nature of the effect of radiation on a solid depends on the type, kinetic energy, mass and charge of the particles that make up this radiation, as well as on the mass, atomic number and density of the material. The article deals with the issues related to the physical models of the impact of ionizing radiation from outer space on the components of spacecraft equipment.
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Nor Azwadi Che Sidik, Raoudha Chaabane, and Hong Wei Xian. "Heat Transfer Study in Cylindrical Cavity with Heat Absorption or Generation." Journal of Advanced Research in Applied Sciences and Engineering Technology 27, no. 2 (August 20, 2022): 16–27. http://dx.doi.org/10.37934/araset.27.2.1627.
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Lattice Boltzmann mesoscopic (LBM) is applied to solve energy equation of a transient conduction radiation heat transfer problem in a two-dimensional cylindrical participating (absorbing, emitting and scattering) medium in the presence of heat generation/absorption coefficient. Control volume finite element method (CVFEM) formulation is used to obtain the radiative information. To study the effectiveness of the LBM-CVFEM combination on unsteady conduction-radiation problems in cylindrical media, the energy equation of the problem is also solved using the finite difference method (FDM) in which the CVFEM is used to compute radiative information. The effects of heat generation/absorption coefficient on temperature distributions in the medium are studied. Results of the present work are benchmarked against those available in the literature. The hybrid numerical model’s results are also compared with those obtained by the FDM-CVFEM combination. All the results presented in this work show that the present method is accurate and valuable for the analysis of cylindrically axisymmetric radiative heat transfer problems .
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Narahari, Marneni, Sowmya Tippa, and Rajashekhar Pendyala. "Unsteady Magnetohydrodynamic Free Convection Flow of a Radiative Fluid Past an Infinite Vertical Plate with Constant Heat and Mass Flux." Applied Mechanics and Materials 465-466 (December 2013): 149–54. http://dx.doi.org/10.4028/www.scientific.net/amm.465-466.149.
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Theoretical analysis of unsteady magnetohydrodynamic free convection flow of a viscous incompressible radiative fluid past an infinite vertical plate with constant heat and mass flux is presented. The dimensionless governing linear partial differential equations have been solved using the Laplace transform technique. The exact solutions for the velocity, temperature and concentration fields are derived. The effects of radiation, magnetic field and buoyancy ratio parameters on the velocity and temperature fields are discussed through graphs. It is found that the velocity increases with increasing radiation parameter whereas it decreases with increasing magnetic field parameter for buoyancy assisted flows.
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Ghosh, S. K., and O. Anwar Beg. "Theoretical Analysis of Radiative Effects on Transient Free Convection Heat Transfer past a Hot Vertical Surface in Porous Media." Nonlinear Analysis: Modelling and Control 13, no. 4 (October 20, 2008): 419–32. http://dx.doi.org/10.15388/na.2008.13.4.14548.
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The purpose of the present investigation deals with the unsteady free convective flow of a viscous incompressible gray, absorbing-emitting but non-scattering, optically-thick fluid occupying a semi-infinite porous regime adjacent to an infinite moving hot vertical plate with constant velocity. We employ a Darcian viscous flow model for the porous medium. The momentum and thermal boundary layer equations are non-dimensionalized using appropriate transformations and then solved subject to physically realistic boundary conditions using the Laplace transform technique. Thermal radiation effects are simulated via a radiation-conduction parameter, Kr, based on the Rosseland diffusion approximation. The influence of Grashof (free convection) number, radiation-conduction parameter (Kr), inverse permeability parameter (Kp) and dimensionless time (t) are studied graphically. We observe that increasing thermal radiation parameter causes a noticeable increase in the flow velocity, u. Temperature, θ, is significantly increased within the boundary layer with a rise in Kr since the latter represents the relative contribution of thermal radiation heat transfer to thermal conduction heat transfer. Increased radiation therefore augments heat transfer, heats the fluid and increases the thickness of the momentum and thermal boundary layers. Velocity is found to decrease with an increase in Kp (inverse permeability parameter) as are shear stress function ( ∂u/∂y | y=0) magnitudes owing to greater resistance of the porous medium for lower permeabilities, which decelerate the flow. An increase in Kr however boosts the shear stress function magnitudes i.e. serves to accelerate the flow. Temperature gradient, ∂θ/∂y | y=0 is also positively affected by an increase in thermal radiation (Kr) and with time. The present study has applications in geological convection, forest fire propagation, glass heat treatment processes at high temperature, metallurgical processing etc.
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Mateos, David, and Manuel Antón. "Worldwide Evaluation of Ozone Radiative Forcing in the UV-B Range between 1979 and 2014." Remote Sensing 12, no. 3 (January 29, 2020): 436. http://dx.doi.org/10.3390/rs12030436.
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Ultraviolet (UV) radiation plays a key role in different planetary mechanisms, thus necessitating a worldwide analysis of this solar spectrum interval. This study offers a worldwide and long-term analysis of ozone radiative forcing (ORF) in the UV-B range between 1979 and 2014. The method uses monthly total ozone column (TOC) values obtained from the ERA-Interim reanalysis data collection and radiative transfer simulations. A global mean ORF of 0.011 Wm−2 is obtained, with marked differences between mid-latitude and tropical areas. The mid-latitude belts in the Northern and Southern Hemispheres exhibit the following statistically significant ORF trends between 1982 and 2014 with respect to pre-1980 values: 0.007 Wm−2 per decade in the 60–45°S belt and around 0.004 Wm−2 per decade in the 45–30°S and 45–60°N belts. The increase observed in the net UV-B radiation levels at the troposphere might have relevant photochemical effects that impact climate change.
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Siddiqa, Sadia, Naheed Begum, S. Noor, and Md Anwar Hossain. "Marangoni Convection Flow Along a Wavy Surface with Non-Linear Radiation." International Journal of Nonlinear Sciences and Numerical Simulation 20, no. 5 (August 27, 2019): 517–25. http://dx.doi.org/10.1515/ijnsns-2016-0120.
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AbstractA boundary-layer analysis is presented for steady, two-dimensional, Marangoni convection along an irregular surface. Thick radiation limit is considered to express the radiative heat flux. A coordinate transformation is adopted to convert the physical domain into computational domain. Implicit finite difference method is then used to obtain the solutions of the problem. The main purpose of this study is to demonstrate the radiation effects on the dissipative layers. Numerical solutions are presented in the form of skin friction coefficient, heat transfer coefficient, velocity and temperature profiles, streamlines and isotherms. It is observed that thermal radiation has a pronounced effect on the flow field and amplitude of the harmonic oscillations also decay with $R_d$. The momentum and thermal boundary-layer thickness increases as $R_d$ gets augmented.
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Mazen E. Assiri, Mazen E. Assiri. "Effects of Various parameters on Radiative Transfer Theory Based Microwave Emission Model." journal of King Abdulaziz University - Meteorology, Environment and Arid Land Agriculture Sciences 27, no. 1 (January 2, 2017): 95–107. http://dx.doi.org/10.4197/met.27-1.9.
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This paper outlines research that is currently being carried out to model the interaction of electromagnetic radiation with earth and atmosphere. Among many others, passive microwave (PM) imagery represents a useful source of data for mapping Earth features. Since, signal of a microwave radiometer is composed of surface and atmospheric contributions, for proper interpretation of the data these effects should be quantified. This research presents analysis of radiative transfer model contributors, which include; the ground based parameters, forest area, water area, and meteorological parameters. The principal objective of this study is to analyze the degree to which brightness temperature can be affected by various earth and atmospheric features. A sensitivity analysis is performed to test the contributing effects of various parameters in radiative transfer theory based microwave emission model. The results of the study show that soil temperature and forest stem volume are the main contributing parameters in estimating brightness temperature values. The results further show that both the earthly located features and atmospheric parameters are important factors that must be taken into account in the development and application of radiative transfer theory based models
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Meloni, Daniela, Alcide di Sarra, Gérard Brogniez, Cyrielle Denjean, Lorenzo De Silvestri, Tatiana Di Iorio, Paola Formenti, et al. "Determining the infrared radiative effects of Saharan dust: a radiative transfer modelling study based on vertically resolved measurements at Lampedusa." Atmospheric Chemistry and Physics 18, no. 6 (March 29, 2018): 4377–401. http://dx.doi.org/10.5194/acp-18-4377-2018.
Повний текст джерелаАнотація:
Abstract. Detailed measurements of radiation, atmospheric and aerosol properties were carried out in summer 2013 during the Aerosol Direct Radiative Impact on the regional climate in the MEDiterranean region (ADRIMED) campaign in the framework of the Chemistry-Aerosol Mediterranean Experiment (ChArMEx) experiment. This study focusses on the characterization of infrared (IR) optical properties and direct radiative effects of mineral dust, based on three vertical profiles of atmospheric and aerosol properties and IR broadband and narrowband radiation from airborne measurements, made in conjunction with radiosonde and ground-based observations at Lampedusa, in the central Mediterranean. Satellite IR spectra from the Infrared Atmospheric Sounder Interferometer (IASI) are also included in the analysis. The atmospheric and aerosol properties are used as input to a radiative transfer model, and various IR radiation parameters (upward and downward irradiance, nadir and zenith brightness temperature at different altitudes) are calculated and compared with observations. The model calculations are made for different sets of dust particle size distribution (PSD) and refractive index (RI), derived from observations and from the literature. The main results of the analysis are that the IR dust radiative forcing is non-negligible and strongly depends on PSD and RI. When calculations are made using the in situ measured size distribution, it is possible to identify the refractive index that produces the best match with observed IR irradiances and brightness temperatures (BTs). The most appropriate refractive indices correspond to those determined from independent measurements of mineral dust aerosols from the source regions (Tunisia, Algeria, Morocco) of dust transported over Lampedusa, suggesting that differences in the source properties should be taken into account. With the in situ size distribution and the most appropriate refractive index the estimated dust IR radiative forcing efficiency is +23.7 W m−2 at the surface, −7.9 W m−2 within the atmosphere, and +15.8 W m−2 at the top of the atmosphere. The use of column-integrated dust PSD from AERONET may also produce a good agreement with measured irradiances and BTs, but with significantly different values of the RI. This implies large differences, up to a factor of 2.5 at surface, in the estimated dust radiative forcing, and in the IR heating rate. This study shows that spectrally resolved measurements of BTs are important to better constrain the dust IR optical properties, and to obtain a reliable estimate of its radiative effects. Efforts should be directed at obtaining an improved description of the dust size distribution and its vertical distribution, as well as at including regionally resolved optical properties.
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Polly, James B., and William B. Rossow. "Cloud Radiative Effects and Precipitation in Extratropical Cyclones." Journal of Climate 29, no. 18 (August 26, 2016): 6483–507. http://dx.doi.org/10.1175/jcli-d-15-0857.1.
Повний текст джерелаАнотація:
Abstract Clouds associated with extratropical cyclones complicate the well-developed theory of dry baroclinic waves through feedback on their dynamics by precipitation and cloud-altered radiative heating. The relationships between cyclone characteristics and the diabatic heating associated with cloud radiative effects (CREs) and latent heat release remain unclear. A cyclone tracking algorithm [NASA’s Modeling, Analysis, and Prediction (MAP) Climatology of Midlatitude Storminess (MCMS)] is used to identify over 106 cyclones in 33 years of the ERA-Interim and collect the properties of each disturbance. Considering storm intensity as related to wind speeds, which depend on the pressure gradient, the distribution of cyclone properties is investigated using groups defined by their depth (local pressure anomaly) and the radius of the region within closed pressure contours to investigate variations with longitude (especially ocean and land), hemisphere, and season. Using global data products of cloud radiative effects on in-atmosphere net radiation [the ISCCP radiative flux profile dataset (ISCCP-FD)] and precipitation (GPCP), composites are assembled for each cyclone group and for “nonstormy” locations. On average, the precipitation rate and the CRE are approximately the same among all cyclone groups and do not strongly differ from nonstormy conditions. The variance of both precipitation and CRE increases with cyclone size and depth. In larger, deeper storms, maximum precipitation and CRE increase, but so do the amounts of nonprecipitating and clear-sky conditions.
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Samir, Mendil, and Aguili Taoufik. "Analysis the effect of Diffraction Phenomena by Complex Shapes with Hybrid MOM-GTD Method." International Journal of Engineering Education 1, no. 2 (December 15, 2019): 67–73. http://dx.doi.org/10.14710/ijee.1.2.67-73.
Повний текст джерелаАнотація:
This article deals with a hybrid method combining the method of moments (MOM) with the general theory of diffraction (GTD). This hybrid approach is used to analyze antennas located near perfectly Bodies of arbitrary curved shape. Some examples, e.g. an antenna mounted near a perfect conductor cylinder with two plates, demonstrates that the hybrid approach is the most suitable technique for modeling large-scale objects and arbitrary shapes. This approach allows us to resolve the problem, that the other methods can’t solve it alone. Generally, random radiation locates on or near an arbitrary form, can be solved using this technique hence the strong advantages of our method.
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Zhan, Weiping. "Efficacy and Safety of Proton Therapy for Medulloblastoma Patients: A Mata-Analysis." Neuroscience and Neurological Surgery 11, no. 2 (January 4, 2022): 01–07. http://dx.doi.org/10.31579/2578-8868/207.
Повний текст джерелаАнотація:
Background: Currently, photon therapy is mainly used for radiotherapy, however, the long-term side effects of photon therapy are sometimes reported, especially in children, including cognitive decline, mental decline, growth retardation, endocrine dysfunction and secondary tumor.Compared with photon radiotherapy, proton therapy is a novel method of radiation therapy, which reduces acute and late radiation damage and improves patients’ quality of life. Therefore, we evaluated proton therapy on medulloblastoma patients by meta-analysis in this study. Materials and Methods: A clinical randomized controlled trial was conducted by retrieving the main databases PubMed (Medline), EMbase, Cochrane Library, Chinese Biomedical Literature Database (CBM), Chinese Zhi-wang (CNKI), Wanfang Database, and VIP Database. We analyzed the literature which matched the quality criteria for the prognostic impact of proton and photon therapy on medulloblastoma patients. Results: Ten articles were included in this study. The overall survival (OS) rate and side effects were comprehensively analyzed. The results showed that proton radiotherapy significantly reduced the side effects and recurrence rate of tumor. Conclusion: Proton therapy could significantly reduce the side effects and recurrence rate of medulloblastoma in patients.
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Khatib, Mutamed. "Evaluation of Electromagnetic Radiation level in the Outdoor from Wireless Transmission Systems in Northern West Bank – Palestine." مجلة جامعة فلسطين التقنية للأبحاث 9, no. 1 (March 30, 2021): 01–09. http://dx.doi.org/10.53671/pturj.v9i1.146.
Повний текст джерелаАнотація:
Exposure to electromagnetic fields is a major public concern due to the possible hazardous effects on health caused by exposure to these radiations. The aims of this study were to measure radiofrequency radiation levels from different wireless systems and to compare the results with the recommended limits by the World Health Organization (WHO) which should be less that 450 µw/cm2. The study was a cross-sectional study that was conducted in different cities and villages from the northern governorates in the West Bank; Jenin, Tulkarm, Nablus, Qalqilya, Tubas and Salfit. To measure the radiation levels ranging from 80 MHz to 2 GHz, a Portable Field Strength Meter with the suitable set of antennas was used. This frequency range covers the radiations from different sources as mobile phone base stations, local radio and television stations, mobile phones, Wireless Local Area Network, Bluetooth, wireless computer periphery and even microwave ovens. Points close to mobile phone base stations and local radio and television stations in addition to randomly selected points were included. The scanning process for each point was done twice and the higher reading was included in the analysis. The results were compared to the recommended limits of radiations by WHO. Also, a questionnaire was distributed to evaluate people knowledge and perception regarding radiations. A total of 2000 readings were obtained with a mean ± SD = 0.25 ± 0.214 µw/cm2. The highest reading was 1.91 µw/cm2. All the readings were below the limits of radiations recommended by the WHO. Most of the readings in the tested area 1184 (59.2%) were between 0.1 -0.45 µw/cm2 which are 1000- 4500 time less than the maximum allowed level (450 µw/cm2), 527 (26.35%) readings were <0.1 µw/cm2, 271 (13.55%) reading were between 0.45-1 µw/cm2 and the rest 17 (0.85%) were >1 µw/cm2 which were still 236-450 times less than the allowed WHO level. Regarding the questionnaire part, most of the participants use mobile phones frequently, they think radiations are dangerous and can cause cancer, they prefer not to have mobile base stations close to their living places. In this study, a scanning for all electromagnetic radiation sources caused by different sources of wireless communication systems showed theoretically no dangerous radiation levels and all the recorded levels were much lower than the recommended levels by the WHO. Most people feel afraid from radiations and think they are dangerous.