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Rinkeviciene, Roma, Algimantas Juozas Poška, and Alvydas Slepikas. "Dynamics of Dust Explosion Localizing System." Solid State Phenomena 164 (June 2010): 79–84. http://dx.doi.org/10.4028/www.scientific.net/ssp.164.79.
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The problem of dust explosion in corn processing enterprises is analyzed. System for localizing of dust explosions with dampers driven by linear induction motors (LIM) is considered. The paper presents the developed mathematical and computer models of a damper drive together with results of simulations.
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Kosinski, Pawel, and Alex C. Hoffmann. "Dust explosions in connected vessels: Mathematical modelling." Powder Technology 155, no. 2 (July 2005): 108–16. http://dx.doi.org/10.1016/j.powtec.2005.05.052.
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Kosinski, P., and A. C. Hoffmann. "Mathematical modelling of dust explosions in interconnected vessels." Nonlinear Analysis: Theory, Methods & Applications 63, no. 5-7 (November 2005): e1087-e1096. http://dx.doi.org/10.1016/j.na.2004.12.020.
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Kosinski, P., R. Klemens, and P. Wolanski. "Potential of mathematical modelling in large-scale dust explosions." Journal de Physique IV (Proceedings) 12, no. 7 (August 2002): 125–32. http://dx.doi.org/10.1051/jp4:20020275.
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Maier, Patrick, Philipp Hartlieb, and Jürgen F. Brune. "Laboratory Scaled Coal Dust Explosions and Physical Test Results for CFD Explosion Models." BHM Berg- und Hüttenmännische Monatshefte 165, no. 6 (April 22, 2020): 265–69. http://dx.doi.org/10.1007/s00501-020-00985-0.
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Sherzod, Zairov, Khudaiberdiev Oibek, Normatova Muborak Zh., and Nomdorov Rustam. "Developing the methods of controlling dust and gas conditions when blasting high benches in deep pits." Izvestiya vysshikh uchebnykh zavedenii Gornyi zhurnal, no. 4 (June 25, 2020): 113–21. http://dx.doi.org/10.21440/0536-1028-2020-4-113-121.
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Research aim is to develop a method of reducing dust and gas emissions concentration at bulk explosions in open pits. Research relevance. When drilling and blasting in open pits, a huge amount of dust and toxic gaseous products is released, and the rate of their formation is affected by the blasting method, the range of explosives used, the method of drilling blast holes, type and sort of stemming, massif water content, rock properties, meteorological conditions, etc. It has been established that in an explosion of 1 kg of explosives, 15% from an average of 900 liters of various gases and gaseous products formed are toxic and dangerous to humans and the environment. To prevent dust and gas emissions, various types of tamping are currently used, which affect not only emissions reduction, but also the efficiency and safety of blasting contributing to the fullest use of explosion energy and increasing the exposure time of the products of explosive 120 "Izvestiya vysshikh uchebnykh zavedenii. Gornyi zhurnal". No. 4. 2020 ISSN 0536-1028 transformation. Despite the significant amount of research and successes achieved in this direction, for deep pits it is necessary to determine the rational parameters of stemming in borehole explosive charges, reduce the formation of toxic gases released in bulk explosions, develop a method of producing an absorption solution capable of neutralizing toxic compounds after an explosion, and develop an effective way to reduce dust and gas emissions in bulk explosions. Research methodology. To solve this problem, integrated research methods were used, including theoretical generalizations and experimental studies in laboratory, testing ground and industrial conditions, methods of mathematical modeling of stemming parameters in borehole explosive charges, methods of mathematical programming using modern computer equipment, as well as methods of mathematical statistics and correlation analysis of research results. Results. Detonation products pressure change in the well has been determined taking into account motion processes of sand and absorbing mixture stemming of various lengths. It has been established that when using stemming made of absorbing mixture, detonation products pressure and escape time are higher compared to sand stemming. The effective stemming length in borehole explosive charges has been established depending on well pressure fall time and stemming length in different sections of the well. Mathematical modeling of stemming parameters in the explosion of borehole explosive charges established the change in pressure in the blast chamber as a function of stemming time and length during its escape from the well, as well as the of stemming escape duration and expiration of detonation products during emulsion explosive blast depending on stemming length. A method has been developed of dust and gas atmospheric pollution parameters determination during the production of bulk explosions in deep pits, An absorption mixture has been developed, which makes it possible to intensify the process of dust deposition above the explosion site and reduce pollution of the surrounding quarry, which favorably affects the environmental situation in the mining region. A method has been developed to reduce dust and gas emissions during blasting operations in open pits, which allows to reduce the concentration of dust and gas clouds formed. Scope of the results. A method of suppressing dust and gas emissions has been introduced at the Muruntau open pit of the Navoi Mining and Metallurgical Combinat. As a result, the process of dust deposition above the explosion site has been intensified, pollution of the surrounding open pit area has been reduced, the concentration of nitrogen dioxide has been reduced by 30.1%, carbon monoxide by 28.6% and sulfur dioxide by 20.5%. The results can be used in quarries where rock crushing is carried out using a blasting method
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Kozubková, M., J. Krutil, and V. Nevrlý. "Experiments and mathematical models of methane flames and explosions in a complex geometry." Combustion, Explosion, and Shock Waves 50, no. 4 (July 2014): 374–80. http://dx.doi.org/10.1134/s0010508214040029.
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FRYER, CHRIS L., AIMEE L. HUNGERFORD, and GABRIEL ROCKEFELLER. "SUPERNOVA EXPLOSIONS: UNDERSTANDING MIXING." International Journal of Modern Physics D 16, no. 06 (June 2007): 941–81. http://dx.doi.org/10.1142/s0218271807010523.
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It has been known since 1987 that many features of supernovae cannot be described by the spherically-symmetric picture assumed in one-dimensional explosion models. However, the study of the propagation of a supernova shock through a star in more than one spatial dimension is still in its infancy. Understanding this propagation, and the mixing associated with it, is critical for determining accurate supernova yields and correctly interpreting observations based on those yields — from gamma-rays and overall light curves produced in supernova explosions to the abundances of isotopes studied in stars. Here we review the current state-of-the-art in this field. By necessity, this problem is computational and therefore provides an ideal setting to discuss how verification and validation techniques can play an important role in taking full advantage of the results from numerical simulations. We discuss this problem using the full arsenal of verification and validation techniques currently available.
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PAULUCCI, L., and J. E. HORVATH. "NU-PROCESS IN EXOTIC MODELS." International Journal of Modern Physics D 19, no. 08n10 (August 2010): 1731–35. http://dx.doi.org/10.1142/s0218271810017238.
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The exact physical conditions generating the abundances of r-elements in environments such as supernovae explosions are still under debate. We evaluated the characteristics expected for the neutrino wind in the proposed model of type-II supernova driven by conversion of nuclear matter to strange matter. Neutrinos will change the final abundance of elements after freeze out of r-process nucleosynthesis, specially those close to mass peaks.
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KOSAREV, Nikolay Petrovich, Vladimir Nikolaevich MAKAROV, Aleksandr Vladimirovich UGOL'NIKOV, Nikolay Vladimirovich MAKAROV, and German Petrovich DYLDIN. "Mine aerology of dust aerosols under conditions of hydro-vortex coagulation." NEWS of the Ural State Mining University, no. 4 (December 20, 2020): 155–65. http://dx.doi.org/10.21440/2307-2091-2020-4-155-165.
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Dust suppression is the most popular method for depositing dust from the air to blast isolation. Improving the isolation system for probable coal dust explosions is an integral part of the problem of dust explosion protection of mining enterprises, the solution of which is one of the most important tasks in the field of occupational safety and health. Purpose: study of physics of the process and the construction of a mathematical model of the movement of aerosols in mine workings in a wide range of changes in the inertial kinematic parameters of the air flow. Research methods. Based on the Boussinesq equation, the Fourier rule and the similarity theorem of complex systems, the analogy of vorticity dispersion and kinematic viscosity, a mathematical model of the movement of dust aerosols under hydro-vortex coagulation conditions is constructed. Some similarity criteria are obtained that ensure the identity of experimental studies and real aerological processes in mines, as well as criterion equations for calculating the coefficient of aerodynamic drag and the time of unsteady inertial motion. Results. Equations are obtained that make it possible to identify aerodynamic processes of aerosol motion under hydro-cyclonic dust suppression through the criteria of Reynolds, Euler and Archimedes, corresponding to the overStokes and Stokes flow regimes. The possibility of reducing the aerodynamic resistance to 20% during hydro-vortex coagulation has been confirmed, which makes it possible to increase the energy efficiency of dust suppression by up to 15% and to increase the turbulization coefficient by at least 20%, thereby reducing the likelihood of a hazardous concentration of dust aerosols. Application. The use of the proposed mathematical model will make it possible to better calculate local aerological processes in mine workings and, as a consequence, to increase the efficiency of turbulization and dust suppression process control at mining enterprises.
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Mendon?a, J. T. "Quantum Models for Classical Dust Particles." Physica Scripta T89, no. 1 (2001): 55. http://dx.doi.org/10.1238/physica.topical.089a00055.
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VISHWAKARMA, R. G., and J. V. NARLIKAR. "QSSC RE-EXAMINED FOR THE NEWLY DISCOVERED SNeIa." International Journal of Modern Physics D 14, no. 02 (February 2005): 345–54. http://dx.doi.org/10.1142/s0218271805006547.
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We examine the possible consistency of the quasi-steady state model with the newly discovered SNe Ia . The model assumes the existence of metallic dust ejected from the SNe explosions, which extinguishes light travelling over long distances. We find that the model shows a reasonable fit to the data, which improves if one take account of the weak gravitational lensing effect of the SNe which have been observed on the brighter side.
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Lee, S. H., S. Vigneswaran, and K. Bajracharya. "Phosphorus transport in saturated slag columns: experiments and mathematical models." Water Science and Technology 34, no. 1-2 (July 1, 1996): 153–60. http://dx.doi.org/10.2166/wst.1996.0367.
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Excessive phosphorus (P as orthophosphate) is one of the major pollutants in natural water that are responsible for algal blooms and eutrophication. P removal by slag is an attractive solution if the P sorption capacity of slag is significant. To design an efficient land treatment facility, basic information on the behaviour of P in the media-water environment is required. In this study, detailed column experiments were conducted to study the P transport under dynamic condition, and mathematical models were developed to describe this process. The column experiments conducted with dust and cake waste products (slag) from a steel industry as adsorbing indicated that they had higher sorption capacity of P than that of a sandy loam soil from North Sydney, Australia. P transport in the dust and cake columns exhibited characteristic S-shaped or curvilinear breakthrough curves. The simulated results from a dynamic physical nonequilibrium sorption model (DPNSM) and Freundlich isotherm constants satisfactorily matched the corresponding experimental breakthrough data. The mobility of P is restricted by the adsorbents and it is proportional to the sorption capacity of them.
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Kessler, D. J., P. D. Anz-Meador, and M. J. Matney. "Space Debris." International Astronomical Union Colloquium 150 (1996): 201–8. http://dx.doi.org/10.1017/s0252921100501547.
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AbstractMan-made, artificial space debris is of interest to the study of interplanetary dust for two reasons: (1) In many regions of Earth orbital space, the space debris flux is larger than the natural meteoroid flux, complicating the study of interplanetary dust, and (2) models and experiments developed to understand space debris may have application to the study of interplanetary dust. The purpose of this paper is to summarize the space debris environment as it is understood today by characterizing the models used to predict the space debris environment and describing the measurements to test the model predictions.Within the last 5 years, the space debris environment has been measured by a number of experiments. These experiments have revealed significant sources of debris in addition to the assumed major source of satellite explosions. Understanding these sources has required the development of more complex models and additional insight into the design and operation of spacecraft. Increased awareness of space debris issues at an international level has led to measures that have reduced the rate of growth in the environment. However, the number of new debris sources discovered seems to be proportional to the number of new measurements of the environment.
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Palla, M., F. Calura, F. Matteucci, X. L. Fan, F. Vincenzo, and E. Lacchin. "The influence of a top-heavy integrated galactic IMF and dust on the chemical evolution of high-redshift starbursts." Monthly Notices of the Royal Astronomical Society 494, no. 2 (April 7, 2020): 2355–73. http://dx.doi.org/10.1093/mnras/staa848.
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ABSTRACT We study the effects of the integrated galactic initial mass function (IGIMF) and dust evolution on the abundance patterns of high redshift starburst galaxies. In our chemical models, the rapid collapse of gas clouds triggers an intense and rapid star formation episode, which lasts until the onset of a galactic wind, powered by the thermal energy injected by stellar winds and supernova explosions. Our models follow the evolution of several chemical elements (C, N, α-elements, and Fe) both in the gas and dust phases. We test different values of β, the slope of the embedded cluster mass function for the IGIMF, where lower β values imply a more top-heavy initial mass function (IMF). The computed abundances are compared to high-quality abundance measurements obtained in lensed galaxies and from composite spectra in large samples of star-forming galaxies in the redshift range 2 ≲ z ≲ 3. The adoption of the IGIMF causes a sensible increase of the rate of star formation with respect to a standard Salpeter IMF, with a strong impact on chemical evolution. We find that in order to reproduce the observed abundance patterns in these galaxies, either we need a very top-heavy IGIMF (β < 2) or large amounts of dust. In particular, if dust is important, the IGIMF should have β ≥ 2, which means an IMF slightly more top-heavy than the Salpeter one. The evolution of the dust mass with time for galaxies of different mass and IMF is also computed, highlighting that the dust amount increases with a top-heavier IGIMF.
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Endeve, E., C. Y. Cardall, R. D. Budiardja, and A. Mezzacappa. "Convection- and SASI-driven flows in parametrized models of core-collapse supernova explosions." Physica Scripta 91, no. 2 (January 21, 2016): 024002. http://dx.doi.org/10.1088/0031-8949/91/2/024002.
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ZANINETTI, LORENZO. "MODELS OF DIFFUSION OF GALACTIC COSMIC RAYS FROM SUPERBUBBLES." International Journal of Modern Physics A 22, no. 05 (February 20, 2007): 995–1026. http://dx.doi.org/10.1142/s0217751x07035215.
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Superbubbles are shells in the interstellar medium produced by the simultaneous explosions of many supernova remnants. The solutions of the mathematical diffusion and of the Fourier expansion in 1D, 2D and 3D were deduced in order to describe the diffusion of nucleons from such structures. The mean number of visits in the the case of the Levy flights in 1D was computed with a Monte Carlo simulation. The diffusion of cosmic rays has its physical explanation in the relativistic Larmor gyro-radius which is energy dependent. The mathematical solution of the diffusion equation in 1D with variable diffusion coefficient was computed. Variable diffusion coefficient means magnetic field variable with the altitude from the Galactic plane. The analytical solutions allow us to calibrate the code that describes the Monte Carlo diffusion. The maximum energy that can be extracted from the superbubbles is deduced. The concentration of cosmic rays is a function of the distance from the nearest superbubble and the selected energy. The interaction of the cosmic rays on the target material allows us to trace the theoretical map of the diffuse Galactic continuum gamma-rays. The streaming of the cosmic rays from the Gould Belts that contains the sun at its internal was described by a Monte Carlo simulation. Ten new formulas are derived.
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FRYER, CHRIS L. "STELLAR COLLAPSE." International Journal of Modern Physics D 12, no. 10 (December 2003): 1795–835. http://dx.doi.org/10.1142/s0218271803004298.
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The collapse of massive stars have been used to explain many of the largest outbursts known to mankind, from supernovae to hypernovae to gamma-ray bursts. These explosions differ in their level of asymmetry and the spectral energy of the photons they emit. It is likely that such a wide range in the nature of these explosions requires more than one explosion mechanism to extract the gravitational potential energy released during the collapse. Three major classes of mechanisms have been proposed: neutrino-driven, magnetic-field driven, collapsar (black hole accretion disk) driven. This review discusses each mechanism in turn, discussing the current state-of-the-art calculations along with their observational predictions. We conclude with a summary of the current observational constraints on these models.
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Kruzhilko, O., R. Cherneha, V. Maystrenko, O. Polukarov, and V. Kalinchyk. "Modelling and forecasting the workplace environmental physical factors values." Archives of Materials Science and Engineering 1-2, no. 100 (November 1, 2019): 21–33. http://dx.doi.org/10.5604/01.3001.0013.5999.
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Purpose: To develop a mathematical model for predicting the workplace environmental physical factors values. Design/methodology/approach: Experimental measurements of the harmful and dangerous physical factors values of workplace environmental were carried out using special certified equipments. For each physical factor, 200 measurements were carried out. The workplace choice is justified by the employees’ survey and specialists’ expert evaluation results. Prediction methods that can be used to predict the workplace environmental physical factors values have been analyzed analytically. Working conditions assessment was carried out in accordance with the classification of working conditions for workplace harmfulness and danger, which function in Ukraine. Findings: For a preliminary assessment of the impact of environmental physical factors on workers, it is proposed to use the strict ranking method. It has been established that the proposed mathematical models for predicting the workplace environmental physical factors values (noise, dust, vibration, relative humidity) have an accuracy of more than 90% and can be used for planning measures to working conditions improve. Research limitations/implications: The results of a study of modelling and forecasting the workplace environmental physical factors values at the enterprise for the manufacture of glass and glass products at workplaces of transportation, preparation and mixing of materials are shown. Mathematical models for four physical factors are presented: noise, dustiness of air, vibration, relative humidity. Practical implications: Mathematical models make it possible to predict the environmental physical factors values (noise, vibration, dust, humidity) taking into account the specifics of the production process, assess the hazard class and harmfulness of working conditions at workplaces and justify the measures at labour protection. Originality/value: For the first time proposed by the mathematical models for predict the environmental physical factors values (noise, vibration, dust, humidity) taking into account the specifics of the production process.
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Freytag, B., F. Allard, H.-G. Ludwig, D. Homeier, and M. Steffen. "Models of surface convection and dust clouds in brown dwarfs." Physica Scripta T133 (December 2008): 014005. http://dx.doi.org/10.1088/0031-8949/2008/t133/014005.
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Eckhoff, Rolf K. "Ignition of Combustible Dust Clouds by Strong Capacitive Electric Sparks of Short Discharge Times." Zeitschrift für Physikalische Chemie 231, no. 10 (October 26, 2017): 1683–707. http://dx.doi.org/10.1515/zpch-2016-0935.
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Abstract It has been known for more than half a century that the discharge times of capacitive electric sparks can influence the minimum ignition energies of dust clouds substantially. Experiments by various workers have shown that net electric-spark energies for igniting explosive dust clouds in air were reduced by a factor of the order of 100 when spark discharge times were increased from a few μs to 0.1–1 ms. Experiments have also shown that the disturbance of the dust cloud by the shock/blast wave emitted by “short” spark discharges is a likely reason for this. The disturbance increases with increasing spark energy. In this paper a hitherto unpublished comprehensive study of this problem is presented. The work was performed about 50 years ago, using sparks of comparatively high energies (strong sparks). Lycopodium was used as test dust. The experiments were conducted in a brass vessel of 1 L volume. A transient dust cloud was generated in the vessel by a blast of compressed air. Synchronization of appearance of dust cloud and spark discharge was obtained by breaking the spark gap down by the dust cloud itself. This may in fact also be one possible synchronization mechanism in accidental industrial dust explosions initiated by electrostatic sparks. The experimental results for various spark energies were expressed as the probability of ignition, based on 100 replicate experiments, as a function of the nominal dust concentration. All probabilities obtained were 0%<p<100%. A tentative mathematical model could be fitted to all the data, assuming that the life time of the spark channel as an effective ignition source increased with the spark energy, that the minimum time of contact between the spark and the dust cloud for ignition to occur was a function of spark energy and nominal dust concentration, and that the stochastic element was the statistical distribution of the time interval between spark appearance and re-establishment of contact between spark channel and dust cloud, following detachment of the dust cloud from the spark by the shock/blast wave emitted by the spark discharge.
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Sandhu, Gurcharn S. "Black Holes are a Mathematical Fantasy, not a Physical Reality." Applied Physics Research 11, no. 4 (July 15, 2019): 16. http://dx.doi.org/10.5539/apr.v11n4p16.
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With recent detection of black hole mergers by LIGO, the 'Black Holes' and 'Neutron Stars' have become common house-hold names, albeit fanciful names in public domain. However, for the scientific community black holes are the ultimate paradoxes of nature. The claimed observations of black hole mergers are in fact interpretations of certain observations under the spacetime model of Relativity. These interpretations can change significantly with the change in operating model of the phenomenon. A black hole is believed to be a ‘region of spacetime’ exhibiting such strong gravitational effects that nothing, not even light can escape from it. We demonstrate in this paper that this conviction is based on erroneous derivation for the gravitational redshift and the correct derivation shows that a photon cannot be prevented from escaping a gravitating body of any mass and size. Due to erroneous depiction of spacetime as a physical entity in GR, a mathematical singularity predicted by Schwarzschild metric solution of EFE has been projected as a physical possibility in the form of Black Holes. To strengthen the physical basis of Black Hole creation, the observations of Super Nova explosions are being interpreted under core collapse models. The core collapse models are now regarded as the physical foundation of Black Holes and Neutron stars. In this paper we have established the invalidity of current core collapse models on the grounds of treating electrons, ions and nuclei as non-interacting particles and using kinetic theory of gases for analyzing compressive stresses in solid iron core.
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Minkin, Maksim, and Denis Kuimov. "Development of the principles of mathematical modelling and management of behaviour of fine dust fractions of various nature in non-uniform electric field." MATEC Web of Conferences 226 (2018): 02029. http://dx.doi.org/10.1051/matecconf/201822602029.
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The main fundamental objective of this work is the research of behaviour of fine dust fractions (aerosols) of various nature in non-uniform electric field (the crown category) in the conditions of action of electric, gravitational, aerodynamic and other indignations. Determination of the fundamental principles and also development of methods of management of particles of fine fraction with the set physical characteristics will allow to develop adequate mathematical behaviour models of aerosols in nonuniform electric field. In the real work mathematical modelling of electrostatic field in the device is described and the mathematical model is presented. The analysis of physical processes in the device of blocking of dust emissions – “an electrostatic lock” taking into account influence of Aerodynamic effort is carried out from such phenomenon as “Ionic wind”.
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Belikov, A. S., N. N. Biliaiev, V. V. Biliaieva, and O. V. Berlov. "Assessment of the dust pollution level in the workspaces by the methods of mathematical modeling." Geo-Technical mechanics, no. 152 (2020): 218–25. http://dx.doi.org/10.15407/geotm2020.152.218.
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Coal dust leakage from coal stacks leads to intensive contamination of the working areas. Therefore, determining level of air pollution near the coal piles for various meteorological situations, when new coal piles are arranged, is an important applied problem. For practice, it is necessary to have quick-calculating mathematical models whiсh take into account the most significant physical processes impacting on formation of contamination zones near the coal piles. Today, to predict the level of air pollution at dust leaking from the coal stacks, the normative technique OND-86 or the Gauss model is used. These forecasting methods make it possible to quickly calculate the contamination zones, but they do not take into account geometric shape of the coal stack and unevenness of the velocity field near it. The subject of this research was creation of a mathematical model for predicting the level of air pollution near coal piles with taking into account the aerodynamics of air flows around them. The purpose of the work was to develop a set of numerical models for quick calculation of the level of air pollution at coal dust leaking from the coal piles with taking into account the uneven emission of dust from different areas of the stack surface. The modelling equations are the three-dimensional mass transfer equation (Marchuk's model) and the three-dimensional equation for the velocity potential. The Marchuk's model allows taking into account rate of the coal dust particles settling, parameters of turbulent diffusion and uneven air flow rate near the coal pile. The Dirac delta function is used for modelling coal dust leaking from various sections of the coal pile. For the numerical solution of the mass transfer equation, a difference splitting scheme is used. On the basis of the three-dimensional equation for the velocity potential, an uneven velocity field near the coal pile is determined. The Richardson method is used for numerical solution of the three-dimensional equation for the velocity potential. An algorithm for solving the problem of calculating a level of contamination of working areas near a coal pile is considered. The description of the structure of the created complex of computer programs is given.
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Kimball, Colin E. "Evaluating Groundwater Pollution Susceptibility of Dust Suppressants and Roadbed Stabilizers: Case Study of a Petroleum-Based Product." Transportation Research Record: Journal of the Transportation Research Board 1589, no. 1 (January 1997): 64–69. http://dx.doi.org/10.3141/1589-11.
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Current environmental regulations have prompted regulatory officials, users, and manufacturers of roadbed stabilizers and dust suppressants to evaluate the environmental impact of these products to ensure that human health and the environment are not compromised through their use. Because roadbed stabilizers and dust suppressants are inherently designed to prevent dust emissions and erosion, this study focuses on evaluating the groundwater pollution susceptibility of roadbed stabilizers and dust suppressants. Current techniques used in evaluating hazardous waste sites to estimate the fate and transport of constituents in the subsurface are useful for evaluating roadbed stabilizers and dust suppressants. Chemical properties of roadbed stabilizers and dust suppressants along with generic soil property parameters can be incorporated into screening-level mathematical models to estimate constituent target-level concentrations in groundwater. These techniques were applied to a petroleum-based soil stabilizer and dust suppressant known as Pennz-Suppress D (petroleum-based product). The content of Environmental Protection Agency priority pollutants was determined by laboratory analysis. Further testing with leachate extraction methods provided additional data on leachability of the petroleum-based products under assumed worst-case conditions. Mathematical modeling was used to qualify the results. Groundwater pollution susceptibility results indicate a low risk for the product to adversely affect groundwater.
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Labovská, Zuzana, and Juraj Labovský. "Estimation of thermal effects on receptor from pool fires." Acta Chimica Slovaca 9, no. 2 (October 1, 2016): 169–79. http://dx.doi.org/10.1515/acs-2016-0029.
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Abstract The aim of this contribution is to provide an overview of the calculation procedures of risk analysis, that is, the effects and consequences of pool fires. Fires and explosions are the most significant and most common causes of damage to equipment and of injuries and death in industry. Damages are a direct consequence of the generated heat flux. Mathematical tools for the prediction of heat flux at a distance can be divided into four classes: semi-empirical models, field models, integral models and zone models. Semi-empirical modeling is a relatively simple technique providing models predicting heat flux at a distance. There are two types of semi-empirical models: point source models and surface emitter models. By their nature, semi-empirical models depend strongly on experimental data. Correlations are able to describe the general features of a fire. Semi-empirical models are ideal for routine hazard assessment purposes because they are mathematically simple, and hence easily understood. However, if more models describing the same phenomenon are available, significant differences in the heat flux prediction can be expected. In this contribution, differences in the prediction of the heat flux from pool fires are discussed.
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Kotov, B., V. Hryshchenko, Yu Pantsyr, and I. Herasymchuk. "Electrotechnological complex for dedusting ventilation exhausts heat recovery units in production facilities and units." Energy and automation, no. 2(54) (June 22, 2021): 118–26. http://dx.doi.org/10.31548/energiya2021.02.118.
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Currently, to create a microclimate in the production facilities of agro-industrial production are widely used utilizers of waste heat of ventilation emissions. But the air of such premises is clogged with dust impurities and has a high moisture content, as a result of which condensate falls on the heat-transfer surfaces, and dust sticks to the moistened surface. As a result, the efficiency of heat exchangers is significantly reduced, and the hydraulic resistance increases, which can cause a decrease in air supply. Therefore, there is a need to combat dust in the air supplied to heat recovery units. The most common method of purification of gas streams from solid dust impurities is the deposition of the latter in electrostatic precipitators, to increase the efficiency of which use gravitational moving water film. Currently, there are no mathematical descriptions and calculated dependences for horizontal electrostatic precipitators and electrohydrocyclones. The aim of the study is to formulate a mathematical description of the processes of movement of solid particles in the chambers of the horizontal electrostatic precipitator and electrohydrocyclone. The analysis of the existing systems of heat utilization of exhaust air and influence of dustiness on efficiency of their use is resulted. The possibility of using various systems for dust cleaning of exhaust air in agro-industrial facilities is considered. The technological and constructive scheme of the electrotechnological complex of utilization of heat of ventilating emissions which includes the electrohydrocyclone for clearing of dust of exhaust air is offered. The effect of determining forces, including electric, on the motion of a dust particle in the rotating flow of an electrohydrocyclone is analyzed. Equations describing the motion of a particle in an air rotating flow under the action of an electric field are determined, and mathematical models are compiled to calculate the trajectory of the dust particle. Simplified analytical expressions for particle motion trajectories are presented. Keywords: dust, separation, electric field, cyclone, airflow
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PATIL, K. D. "ANALYSIS OF TRAPPED SURFACES IN HIGHER DIMENSIONAL DUST COLLAPSE." International Journal of Modern Physics D 15, no. 02 (February 2006): 251–59. http://dx.doi.org/10.1142/s0218271806007705.
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We analyze the dynamics of an apparent horizon in higher dimensional (HD) dust collapse. We have taken into consideration two different types of dust models. We propose the concept of a "trapped range" of initial data in different higher dimensional space–times. We show that "trapped range" of initial data increases with the increase in dimensions of the space–times.
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Amekhyan, A. "The structure of galactic halos and the microwave temperature maps." International Journal of Modern Physics D 28, no. 16 (October 16, 2019): 2040016. http://dx.doi.org/10.1142/s0218271820400167.
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The study of Planck microwave temperature maps toward several nearby spiral edge-on galaxies had revealed frequency-independent temperature asymmetry detection of Doppler origin in their halos. The contribution of the dust component to that effect is studied in this paper, particularly for the case of the M31 galaxy, using the models of dust emission and the phenomenological profiles of the dark matter configurations. The obtained results are in accordance with those inferred from the microwave temperature asymmetry data, thus indicating the possible contribution of dust, among other radiation mechanisms, in revealing the dark halo parameters.
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Vasenin, Igor, Anatoliy Glazunov, Vladimir Shuvarikov, Ivan Eremin, Anuar Kagenov, and Kirill Kostyushin. "The physical aspects of gas dynamic and thermal physics processes mathematical modelling of descent spacecraft’s." Thermal Science 23, Suppl. 2 (2019): 513–18. http://dx.doi.org/10.2298/tsci19s2513v.
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The article discusses the physical aspects and assumptions in the formulation of the gas dynamics and thermal physics models in conditions of ?Luna - Resource? spacecraft landing on the Moon surface. It was proposed to divide the problem into two stages: calculation of the gas phase and determination of trajectories and heating of particles of lunar dust. The use of the continuum equations and not taking into account the reverse effect of particles on gas was substantiated. The calculation results of parameters impingement exhaust jet of spacecraft propulsion system with Moon surface are given. It was obtained that a reverse external force is added to the streamlined surfaces equal to 196 N, the gas temperature at the bottom of the cargo compartment reaches 2000 K, and the calculated heat flux was 400 kW. The trajectories of the particles of lunar dust was determined and it was found that with a size of 1 ?m the distance of their flight range was 3.5 km.
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Schady, Patricia. "Gamma-ray bursts and their use as cosmic probes." Royal Society Open Science 4, no. 7 (July 2017): 170304. http://dx.doi.org/10.1098/rsos.170304.
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Since the launch of the highly successful and ongoing Swift mission, the field of gamma-ray bursts (GRBs) has undergone a revolution. The arcsecond GRB localizations available within just a few minutes of the GRB alert has signified the continual sampling of the GRB evolution through the prompt to afterglow phases revealing unexpected flaring and plateau phases, the first detection of a kilonova coincident with a short GRB, and the identification of samples of low-luminosity, ultra-long and highly dust-extinguished GRBs. The increased numbers of GRB afterglows, GRB-supernova detections, redshifts and host galaxy associations has greatly improved our understanding of what produces and powers these immense, cosmological explosions. Nevertheless, more high-quality data often also reveal greater complexity. In this review, I summarize some of the milestones made in GRB research during the Swift era, and how previous widely accepted theoretical models have had to adapt to accommodate the new wealth of observational data.
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KHADEKAR, G. S., VRISHALI PATKI, and R. RADHA. "STRING DUST COSMOLOGICAL MODEL IN HIGHER-DIMENSIONAL SPACE–TIME." International Journal of Modern Physics D 14, no. 09 (September 2005): 1621–34. http://dx.doi.org/10.1142/s0218271805007292.
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We have investigated the bulk viscous fluid string dust cosmological model in the higher dimensional space–time. To obtain a determinate solution, it is assumed that the coefficient of bulk viscosity is a power function of the energy density τ = τcρm(t) and the scalar of expansion is proportional to shear scalar, which leads to a relation between metric potentials A = KRn where A and R are functions of time. It is also observed that models appear to be singular at [Formula: see text] and [Formula: see text] in the presence and absence of bulk viscosity and for n = 1, the model represent an isotropic universe. The physical and geometrical aspects of the model are also discussed.
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Abebe, Amare, and Maye Elmardi. "Irrotational-fluid cosmologies in fourth-order gravity." International Journal of Geometric Methods in Modern Physics 12, no. 10 (October 25, 2015): 1550118. http://dx.doi.org/10.1142/s0219887815501182.
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In this paper, we explore classes of irrotational-fluid cosmological models in the context of f(R)-gravity in an attempt to put some theoretical and mathematical restrictions on the form of the f(R) gravitational Lagrangian. In particular, we investigate the consistency of linearized dust models for shear-free cases as well as in the limiting cases when either the gravito-magnetic or gravito-elecric components of the Weyl tensor vanish. We also discuss the existence and consistency of classes of non-expanding irrotational spacetimes in f(R)-gravity.
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Cheng, Yu Ting, Zhao Peng Jia, and Shi Liu. "Numerical Study of the Co-Firing Pulverized Coal and Biomass." Applied Mechanics and Materials 170-173 (May 2012): 3419–24. http://dx.doi.org/10.4028/www.scientific.net/amm.170-173.3419.
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This study presented Computational Fluid Dynamic (CFD) analysis of the effect of co-firing coal blended with biomass, which is saw dust here. This complex problem which is because of its turbulent on the chemical reactions has been simulated in this paper for the purpose to decline the large amount of cost of doing experiment. The CFD analysis includes the prediction of vectors of the gas phase and DPM burnout result alike. What’s more, the reduction of CO2 by coal blended with different proportions of biomass has been presented because of low content of char in biomass. The mathematical models consist of models for turbulence flow(RNG K-EPSILON MODEL);non-premixed model with two mixture fractions/PDF model; and radiation (P-1 radiation model). The coal is from An Qin in China, and then respectively blended with 5% and 10% saw dust for co-combustion.
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Munyeshyaka, Albert, Joseph Ntahompagaze, and Tom Mutabazi. "Cosmological perturbations in f(G) gravity." International Journal of Modern Physics D 30, no. 07 (April 29, 2021): 2150053. http://dx.doi.org/10.1142/s021827182150053x.
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We explore cosmological perturbations in a modified Gauss–Bonnet [Formula: see text] gravity, using a [Formula: see text] covariant formalism. In such a formalism, we define gradient variables to get perturbed linear evolution equations. We transform these linear evolution equations into ordinary differential equations using a spherical harmonic decomposition method. The obtained ordinary differential equations are time-dependent and then transformed into redshift-dependent. After these transformations, we analyze energy-density perturbations for two fluid systems, namely, for a Gauss–Bonnet field-dust system and for a Gauss–Bonnet field-radiation system for three different pedagogical [Formula: see text] models: trigonometric, exponential and logarithmic. For the Gauss–Bonnet field-dust system, energy-density perturbations decay with increase in redshift for all the three models. For the Gauss–Bonnet field-radiation system, the energy-density perturbations decay with increase in redshift for all of the three [Formula: see text] models for long wavelength modes whereas for short wavelength modes, the energy-density perturbations decay with increasing redshift for the logarithmic and exponential [Formula: see text] models and oscillate with decreasing amplitude for the trigonometric [Formula: see text] model.
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SINGH, C. P., and SURESH KUMAR. "BIANCHI TYPE-II COSMOLOGICAL MODELS WITH CONSTANT DECELERATION PARAMETER." International Journal of Modern Physics D 15, no. 03 (March 2006): 419–38. http://dx.doi.org/10.1142/s0218271806007754.
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A special law of variation for Hubble's parameter in anisotropic space–time models that yields a constant value of the deceleration parameter is presented. Also, a spatially homogeneous and anisotropic but locally rotationally symmetric (LRS) Bianchi type-II cosmological model is studied with a perfect fluid and constant deceleration parameter. Assuming the equation of state p = γρ, where 0≤γ≤1, and using a special law of variation for the Hubble parameter, we are able to construct many new solutions to Einstein's field equations of LRS Bianchi type-II for four different physical models (dust, radiation, Zel'dovich and vacuum). We discuss the solutions with power-law and exponential expansion and examine a particular class of models. A detailed study of kinematic, geometrical and observational properties is carried out.
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Herbst, Eric. "Models of Gas-Grain Chemistry in Star-forming Regions." Symposium - International Astronomical Union 197 (2000): 147–59. http://dx.doi.org/10.1017/s0074180900164757.
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It is difficult if not impossible to explain the abundances of assorted interstellar molecules in both the gaseous and condensed phases without the use of grain chemistry. Unfortunately, the chemistry occurring on grains is not well understood because of a variety of uncertainties including the nature, size, and shape of dust particles, the binding energies of key species, the dominant mechanism of surface chemistry, and the correct mathematical treatment of surface processes. Still, intrepid astrochemists have used granular chemistry in chemical models of an assortment of sources including cold clouds, protostellar disks, and hot cores. Indeed, the dominant explanation of the saturated gas-phase molecules observed in hot cores involves grain chemistry during an earlier, low temperature phase. Although gas-grain models have elucidated major features of the chemistry, much more work remains to be accomplished before they can be used to help characterize the physical conditions in star-forming regions and their temporal variations.
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Cheberiachko, Serhii, Olena Yavorska, Yurii Cheberiachko, and Andrii Yavorskyi. "Analysis of pressure difference changes in respirator filters while dusting." E3S Web of Conferences 60 (2018): 00012. http://dx.doi.org/10.1051/e3sconf/20186000012.
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Objective is to determine the relation between pressure difference of a filter and parameters of a filtering layer to lengthen the protection period. The study involved elements of system analysis and mathematical modeling. Basic statements of the theory of nonstationary filtration and aerohydrodynamics were applied to develop a dust-loaded filter model. Dependence of pressure difference in a filter upon certain changes in packaging density of dust-loaded fibers has been determined; the dependence makes it possible to define minimum fiber packaging density to provide maximum dust capacity. To provide maximum dust capacity and high protective efficiency, the number of filtering layers in multilayered filters depends upon dust concentration within the air of the working zone, specified protection level of a respirator, air loss, and maximum dust volume which may be accumulated in the finishing filtering layer in terms of fiber packaging density being determined according to the minimum pressure difference in a filter at final time of respirator operation. A model of changes in pressure difference in filtering respirators in the process of aerosol particles depositing on filters has been improved; contrary to other available models, that one takes into consideration changes in fiber packaging density while dusting, filtration coefficient, and the amount of aerosol particles.
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LEBO, I. G., N. N. DEMCHENKO, A. B. ISKAKOV, J. LIMPOUCH, V. B. ROZANOV, and V. F. TISHKIN. "Simulation of high-intensity laser–plasma interactions by use of the 2D Lagrangian code “ATLANT-HE”." Laser and Particle Beams 22, no. 3 (July 2004): 267–73. http://dx.doi.org/10.1017/s0263034604223096.
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Hot electrons may significantly influence interaction of ultrashort laser pulses with solids. Accurate consideration of resonant absorption of laser energy and hot electron generation at a critical surface was achieved through the developed physical and mathematical models. A two-dimensional (2D) ray-tracing algorithm has been developed to simulate laser beam refraction and Bremsstrahlung absorption with allowance for nonlinear influence of a strong electromagnetic field. Hot electron transport was considered as a straight-line flow weakening by a friction force calculated in the approximation of the average state of ionization. Developed models were coupled with the 2D Lagrangian gas dynamic code “ATLANT” that takes into account nonlinear heat transport. The developed program has been applied to simulate irradiation of Al foils by picosecond laser double pulses. Hot electron transport and heating resulted in thin foil explosions. The transition from the exploding foil regime to the ablative one with foil thickening has been simulated and analyzed at various values of laser light intensity. In second series of calculations we have modeled the interaction of a nanosecond iodine laser with a two-layered target.
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Bastrukov, Sergey, and Jongmann Yang. "Dissipative-free Models for Wave Dynamics of Interstellar Gas-dust Medium in Galactic Magnetic Fields." Physica Scripta 65, no. 4 (January 1, 2002): 340–44. http://dx.doi.org/10.1238/physica.regular.065a00340.
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Stark, C. R., and D. A. Diver. "Dust cloud evolution in sub-stellar atmospheres via plasma deposition and plasma sputtering." Astronomy & Astrophysics 611 (March 2018): A91. http://dx.doi.org/10.1051/0004-6361/201731253.
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Context. In contemporary sub-stellar model atmospheres, dust growth occurs through neutral gas-phase surface chemistry. Recently, there has been a growing body of theoretical and observational evidence suggesting that ionisation processes can also occur. As a result, atmospheres are populated by regions composed of plasma, gas and dust, and the consequent influence of plasma processes on dust evolution is enhanced.Aim. This paper aims to introduce a new model of dust growth and destruction in sub-stellar atmospheres via plasma deposition and plasma sputtering.Methods. Using example sub-stellar atmospheres from DRIFT-PHOENIX, we have compared plasma deposition and sputtering timescales to those from neutral gas-phase surface chemistry to ascertain their regimes of influence. We calculated the plasma sputtering yield and discuss the circumstances where plasma sputtering dominates over deposition.Results. Within the highest dust density cloud regions, plasma deposition and sputtering dominates over neutral gas-phase surface chemistry if the degree of ionisation is ≳10−4. Loosely bound grains with surface binding energies of the order of 0.1–1 eV are susceptible to destruction through plasma sputtering for feasible degrees of ionisation and electron temperatures; whereas, strong crystalline grains with binding energies of the order 10 eV are resistant to sputtering.Conclusions. The mathematical framework outlined sets the foundation for the inclusion of plasma deposition and plasma sputtering in global dust cloud formation models of sub-stellar atmospheres.
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James, William, and Boregowda Shivalingaiah. "Storm water pollution modelling: buildup of dust and dirt on surfaces subject to runoff." Canadian Journal of Civil Engineering 12, no. 4 (December 1, 1985): 906–15. http://dx.doi.org/10.1139/l85-103.
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Many runoff models are currently in use to predict both the quantity and quality of storm water runoff. In most models, the quality algorithms need further development to gain the confidence of model users. The writers have attempted to disaggregate the accumulation process and to develop improved algorithms for pollutant buildup. The factors and processes that affect buildup include atmospheric dustfall due to plumes of dust-laden air, wind effects, vehicles, intentional removals (e.g., street cleaning), special activities (such as construction and demolition), biological decomposition, and population-related activities (e.g., vegetation density, insecticides, herbicides, fertilizers, and lawn cutting). Mathematical expressions for each of these mechanisms are presented and utilized to develop algorithms in the RUNOFF module of the SWMM3 package.A separate multiregression model is used to generate atmospheric dustfall from meteorological information; this is input to the new program (NEWBLD) to calculate pollutant accumulation on individual subcatchments. NEWBLD is interfaced with the RUNOFF block of SWMM3. A sensitivity analysis is carried out using data for the Chedoke Creek catchment in Hamilton, Ontario. The modified version of the SWMM3 RUNOFF block developed herein by incorporating the new water quality algorithms is called CHGQUAL. It is applied to an urban catchment in Hamilton, Ontario. Key words: storm water models, dust and dirt buildup, storm water pollution, urban hydrology, air pollution.
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Grecea, Danut, Gabriela Pupazan, Zoltan Vass, Cosmin Colda, and Adriana Andris. "Analysis of the purge time values for pressurized enclosure using a parameterized CFD model." MATEC Web of Conferences 342 (2021): 04005. http://dx.doi.org/10.1051/matecconf/202134204005.
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The use of computerized simulations offers definite advantages in understanding phenomena and analysing parameters that have influence during a complex process, more can provide on the basis of scenarios valuable information on the effects for physical processes analysed. Thus, in this paper, using mathematical models and numerical solutions based on physical principles and functions with assumed accuracy are analyse, using CFD (Computational fluids dynamics), the values of purge time for pressurized enclosure, resulting in the action of post-processing of construction for graphs and colour icons, in order to render images as representative possible both for the design phase of the equipment with protection type pressurization “p” and for their evaluation for certification. Determining the values of purging time by using computer simulations is particularly important for avoiding catastrophic events caused by explosions that can lead to human casualties, significant material losses or have significant environmental consequences.
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Podviezko, Valentinas, and Henrikas Sivilevičius. "THE STUDY OF THE STABILITY OF ASPHALT CONCRETE MIXTURE COMPOSITION OPTIMIZATION MATHEMATICAL MODELS USING IMITATIVE SIMULATION." TRANSPORT 18, no. 6 (December 31, 2003): 259–66. http://dx.doi.org/10.3846/16483840.2003.10414108.
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The method of statistical imitative simulation (Monte-Carlo) was used to simulate the heterogeneity of the produced asphalt concrete mixture (ACM) mineral part grading. The stability of optimisation of mathematical models of ACM composition developed by us was tested by a computer using tpe theory of this method application. Average values aij and their average standard deviations σ ij of seven (Aj = 7) finally hatched aggregate partial residues on control sieves i (i = 9) were set for research. Imported filler A 1 and reclaimed dust A 2 were replaced by their mixture Ā1 when the accepted ratio of these materials masses λ is 1, 2 and 3. The maximum (A max) and minimum (A j min) values of ACM materials quantity optimal composition were calculated from numerical values of aggregate with different heterogeneity ((minimum - σ ijmin, medium - σ ijvid , maximum - σ ijmax) increasing the number of computer imitations N (100, 300, 500, 1000, 5000, 10 000). The graphs of the difference between the calculated maximum and minimum values of optimal quantity of aggregate dependence ΔAj on the imitation number N are presented. Calculation results proved the sufficient stability and practical application of the used optimization mathematical model to forecast ACM heterogeneity, when the heterogeneity and optimal quantity of the aggregate used in the mixture are known.
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Azarov, A. V., N. S. Zhukova, E. Yu Kozlovtseva, and D. R. Dobrinsky. "Obtaining mathematical models for assessing efficiency of dust collectors using integrated system of analysis and data management STATISTICA Design of Experiments." Journal of Physics: Conference Series 1015 (May 2018): 032010. http://dx.doi.org/10.1088/1742-6596/1015/3/032010.
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Bezpalova, Alla, Vladimir Lebedev, and Yuri Morozov. "ANALITIC INVESTIGATION OF THE REGULARITIES OF CHANGING DUST CONCENTRATION DURING THE ABRASIVE DECREASE OF STONE STRUCTURES." EUREKA: Physics and Engineering 2 (March 30, 2018): 28–39. http://dx.doi.org/10.21303/2461-4262.2018.00584.
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In the process of repair or restoration of building structures, it is often necessary to strengthen building structures from limestone-shell rock, concrete, reinforced concrete, hard materials-granite, basalt, etc. by cutting or making cuts of the required size with detachable circles of synthetic diamond and cubic boron nitride (CA and CBN) The cutting process is accompanied by considerable dust formation, which can be both harmful and dangerous factor in the work. The aim of the work is studying the process of dust sedimentation and the regularity of the change in dust concentration during the abrasive cutting of concrete and stone materials. Mathematical models have been developed – dust emission from under the wheel, speed of sedimentation of dust particles depending on their material, size and shape, and also depending on temperature, pressure and humidity, the concentration of dust in the working space and the concentration change during the cutting cycle are calculated. It is shown that the velocity of the sedimentation of particles depends significantly on the shape. The higher the sphericity, the higher the sedimentation rate. The ambient temperature has little effect on the sedimentation rate, in the temperature range (-20 → + 40 °C) at which the operation takes place. The sedimentation rate of dust particles generated by cutting the most common building stone materials also differs slightly. Almost the same sedimentation rate has dust particles obtained by cutting basalt and concrete. A bit higher is the sedimentation rate of particles from granite. The sedimentation rate of particles of generated dust is about 600-700 cm/h or 10-11 cm/min for particles measuring 6 μm. This means that at a production height of about 2 m (200 cm) during the operating cycle (about 3 min), the dust will remain at an altitude of about 1.5 m, i.е. practically remains in the working area. This gives grounds to assert about a high concentration of dust during the cutting cycle (about 4.8 108/m3).
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Yurko, Volodymyr, Anton Ganzha, Oleksandra Tarasenko, and Larysa Tiutiunyk. "Improvement of methods for calculating thermal characteristics of loop air heaters." Eastern-European Journal of Enterprise Technologies 1, no. 8 (109) (February 26, 2021): 36–43. http://dx.doi.org/10.15587/1729-4061.2021.225330.
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Utilization of heat from gases leaving the waelz process is a promising way to increase its energy efficiency and environmental safety. Taking into account the gas dustiness, the most rational is the use of a loop air heater, which is a multi-pass and multi-section heat exchanger with a complex mixed scheme of coolant movement. In modern conditions, when the methods and means of calculation of such devices are simplified, the task of obtaining improved methods and means of calculation, determining the efficiency and reliability of their work is relevant. Two mathematical models of the process of heat transfer and hydroaerodynamics in a multi-pass tubular air heater with a cross-circuit of coolants are used. The developed models for the loop air heater are based on the main methods of thermal calculation: a simpler method of correction factor to the average logarithmic temperature pressure and a discrete P-NTU method, which allows obtaining local thermal characteristics of the surface. Diagrams of distribution of heat transfer coefficients, heat transfer, local temperatures of flue gases, air and pipe walls are constructed. The influence of dust and dust particle size on heat transfer is determined. When the flue gas dust is 50 g/Nm3 and with a dust particle size of 1 μm, the heat transfer coefficient increases by 12 %. The application of the air heater design with different schemes of coolant movement is substantiated. The developed universal methods allow determining the thermal productivity of heat exchangers and obtaining the distribution of local temperature characteristics on the heating surface. It is also possible to identify places of possible overheating of the heat exchange surface and the course of corrosion processes, taking into account the design of recuperators, operating conditions, operating modes and different schemes of coolant movement
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Hu, Man Yin, Chao Du, and Bo Yang. "Study on Energy Saving and Emission Reduction of EP Low-Voltage Power Supply System in Power Plant." Advanced Materials Research 219-220 (March 2011): 1109–12. http://dx.doi.org/10.4028/www.scientific.net/amr.219-220.1109.
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According to operation situation of power plant’s EP, the technical measures of energy saving in low-voltage power supply system have been analyzed over the years. Based on the classical theory of electrostatic precipitator and the operating status quo of EP, the paper has been focused on the principles of energy-saving and emission-reduction EP, established high-voltage current supply energy-saving and emission-reduction EP dust removal efficiency of mathematical models, analyzed energy saving and emission reduction technical measures of the low voltage device and proposed the technical solutions. It provided reference for design, adjustment, operation and energy saving of power plant’s EP.
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Cheberyachko, Serhii, Yurii Cheberyachko, Dmytro Radchuk, Oleg Deryugin, and Olha Nesterova. "Improvement of the procedure of new filter masks development." MATEC Web of Conferences 305 (2020): 00038. http://dx.doi.org/10.1051/matecconf/202030500038.
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The purpose is to substantiate theoretically the design of elastomeric half mask and canister of respirator of long-term protection. To develop the models for theoretical calculations of protective properties of dust masks the theory of non-stationary filtration and hydro aerodynamics was applied. To develop the digital model of a head the downhill simplex method was applied reflecting separate face features considering sex or age; to determine the halfmask surface the free energy equation for bowed plate being described by two-dimension spline surface was used with its unknown coefficients determined by method of proportional parts based on three-dimension coordinates of anthropometric face features. The main anthropometric face features influencing halfmasks design were determined to develop polygonous 3D model of head. According to its determined basic coordinates the surface of halfmask was determined using method of interpolation. Considering the mathematical model describing the movement of dust flows near a halfmask and in canister the dependences of distribution of air flow speed in a canister of variable geometry were set and kinematic parameters of dust-laden airflow according to a canister volume were determined. Reasonable geometric parameters of canister were determined; transient modulation from filter to inlet valve hole is performed as a contractor.
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Woodward, C. E., and S. Starrfield. "Recent observational and theoretical studies of the classical nova outburst1This review is part of a Special Issue on the 10th International Colloquium on Atomic Spectra and Oscillator Strengths for Astrophysical and Laboratory Plasmas." Canadian Journal of Physics 89, no. 4 (April 2011): 333–43. http://dx.doi.org/10.1139/p11-010.
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Many facets of astrophysics are captured in classical novae (CNe) eruptions, making these systems unique laboratories to investigate several poorly understood processes, many in real time. CNe may also be related to the super-soft sources, the likely progenitors of SN Ia explosions. Spectra of CNe ejecta, from X-ray to infrared (IR) wavelengths, are remarkable for the changing elemental and ionic content as the ejecta temporally evolves — often exhibiting a variety of low-energy permitted lines of CNO and Fe II, high ionization lines, e.g., [Fe VIII] λ 6078 Å, and IR “coronal” lines (few 100 eV transitions) of metals such as Ne, Si, S, and Ar. At higher energies, X-ray and UV emission in CNe comes from the nuclear burning of residual accreted material on the white dwarf surface after the initial outburst; this emission directly probes processes powering the post-outburst evolution of the white dwarf and the ejecta. Some nova systems are observed to form dust, making CNe one of the known in situ stellar sources of dust grains. However, from a theoretical standpoint the interpretation of the emission line spectra, the derivation of metal abundances and estimates of ejecta mass are vexed by limited and (or) uncertain atomic and molecular data that is becoming increasingly acute, as spectral resolution and wavelength coverage expands into heretofore new observational phase space. Here we highlight IR observations of select CNe, including V2467 Cygni and V2361 Cygni, studied with the NASA Spitzer telescope and contemporaneously with ground-based optical spectroscopy as well as Swift, Chandra, and XMM-Newton spectrophotometry. We discuss new paradigms derived from photoionization models, recent issues associated with ejecta abundances derived from hydrodynamical codes simulating the nova outburst, and future challenges.