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کاربرد نوع شرط:
- جایگاه : پژوهشی
- مجله: International Journal of Nano Dimension
- نوع مقاله: Journal Article
- کلمات کلیدی: DoS,B3LYP,CO adsorption,Cu nanoclusters,LanL2DZ
- چکیده:
- چکیده انگلیسی: First-principle calculations were carried out to investigate the adsorption of CO over Cun nanoclusters. The structural, spectroscopic and electronic properties like optimized geometries, HOMO (highest occupied molecular orbital) and LUMO (lowest unoccupied molecular orbital) energy levels, binding energy, adsorption energy, vibrational frequency and density of states (DOSs) of the pure Cun nanoclusters, and CunCO complexes in their ground state were thoroughly analyzed. The CO adsorbed on the Cun nanoclusters showed a stretch frequency at 1950-2052 cm-1, which was red-shifted relative to that of gas-phase CO (2143 cm-1). This red-shift was believed to arise from the charge transfer from the Cu metal d states to the CO antibonding 2π* level. The CO adsorption on the Cu nanoclusters was chemisorption in nature with the Cu–C bond length (adsorption height) in the range of 1.85-1.92 Å.
- انتشار مقاله: 20-09-1395
- نویسندگان: Razieh Habibpour,Eslam Kashi,Raheleh Vaziri
- مشاهده
- جایگاه : پژوهشی
- مجله: Advances in Environmental Technology
- نوع مقاله: Journal Article
- کلمات کلیدی: Pollution,urban block,urban canyons,CFD,Envi-met
- چکیده:
- چکیده انگلیسی: With the wind permanent flow in the cities, obtaining the minimal pollution in the environment is accessible. Different policies have been considered for optimization of cities such as attachment and or reduction of building parts like air-traps, ceiling forms and so on. Due to population growth in cities and the increasing need for resettlement these people in the cities, inevitably, to the high-rise buildings have gone. The people living in high-rise buildings to meet the needs of their vital urban open spaces are forced to use. To have knowledge about air pollution through buildings, the CFD based software of Envi-met is used. In this case, we can say that the best angle to transfer pollution is the angle of 30 degrees. Also in an ideal case with imposed changes in the form, we could enhance the problem by better navigation of inside wind of urban canyons into spaces between blocks of buildings that have the capacity to trap the particles. Final it is found that we may be able to have more optimal results for transition of pollutions by suitable orientation of blocks against the wind direction of blow.
- انتشار مقاله: 24-12-1394
- نویسندگان: Seyyed Hossein Hosseini,Amir Hossein Peyman Rad,Eslam Kashi
- مشاهده
- جایگاه : پژوهشی
- مجله: Advances in Environmental Technology
- نوع مقاله: Journal Article
- کلمات کلیدی: Gas dispersion,Computational Fluid Dynamic,Chlorine gas,hazard simulation,Water-treatment facility
- چکیده:
- چکیده انگلیسی: In some instances, it is inevitable that large amounts of potentially hazardous chemicals like chlorine gas are stored and used in facilities in densely populated areas. In such cases, all safety issues must be carefully considered. To reach this goal, it is important to have accurate information concerning chlorine gas behaviors and how it is dispersed in dense urban areas. Furthermore, maintaining adequate air movement and the ability to purge ambient from potential toxic and dangerous chemicals like chlorine gas could be helpful. These are among the most important actions to be taken toward the improvement of safety in a big metropolis like Tehran. This paper investigates and analyzes chlorine gas leakage scenarios, including its dispersion and natural air ventilation effects on how it might be geographically spread in a city, using computational fluid dynamic (CFD). Simulations of possible hazardous events and solutions for preventing or reducing their probability are presented to gain a better insight into the incidents. These investigations are done by considering hypothetical scenarios which consist of chlorine gas leakages from pipelines or storage tanks under different conditions. These CFD simulation results are used to investigate and analyze chlorine gas behaviors, dispersion, distribution, accumulation, and other possible hazards by means of a simplified CAD model of an urban area near a water-treatment facility. Possible hazards as well as some prevention and post incident solutions are also suggested.
- انتشار مقاله: 08-11-1393
- نویسندگان: Eslam Kashi,Farshad Mirzaei,Farzad Mirzaei
- مشاهده