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    Synthesis of dimethyl ether over modified H-mordenite zeolites and bifunctional catalysts composed of Cu/ZnO/ZrO2 and modified H-mordenite zeolite in slurry phase

    , Article Catalysis Letters ; Volume 129, Issue 1-2 , 2009 , Pages 111-118 ; 1011372X (ISSN) Khandan, N ; Kazemeini, M ; Aghaziarati, M ; Sharif University of Technology
    Synthesis of dimethyl ether (DME) via methanol dehydration were investigated over various catalysts, and via direct CO hydrogenation over hybrid catalysts composed of Al-modified H-Mordenite zeolite and Cu/ZnO/ZrO 2. H-Mordenite zeolite exhibited the highest activity in dehydration of methanol. However, its selectivity toward dimethyl ether was rather low. For this reason, the H-Mordenite was modified. Modification of zeolites was performed by wet impregnation method and considered catalysts were characterized by AAS, XRD and NH3-TPD analyses. Results of catalytic tests indicated that H-Mordenite modified with 8 wt% aluminum oxide was the best catalyst for synthesis of dimethyl ether from... 

    Application of temperature transient analysis for welltest interpretation and well productivity evaluation

    , Article Society of Petroleum Engineers - SPE Asia Pacific Oil and Gas Conference and Exhibition, Jakarta, Indonesia,October 30–November 1, 2007 ; 2007 ; 9781613990407 (ISBN) Bahrami, N ; Siavoshi, J ; Sharif University of Technology
    During transient tests, both pressure and temperature are changed depending on downhole flow rate. In gas producing wells, Joule-Thomson cooling and frictional heating effects are the main dynamic factors causing flowing bottomhole temperature to differ from the static formation temperature at that depth. When a gas well is shut in, JT cooling effect is vanished and this causes a sharp increase in sandface temperature. As effect of wellbore storage ends, wellbore temperature gradually cools down due to heat conduction with near wellbore region. This paper demonstrates a new technique for using temperature transient data in gas wells in order to determine end of wellbore storage. Also, effect... 

    A comparison of light-duty vehicles' high emitters fractions obtained from an emission remote sensing campaign and emission inspection program for policy recommendation

    , Article Environmental Pollution ; Volume 286 , 2021 ; 02697491 (ISSN) Hassani, A ; Safavi, S. R ; Hosseini, V ; Sharif University of Technology
    Elsevier Ltd  2021
    Urban transportation is one of the leading causes of air pollution in big cities. In-use emissions of vehicles are higher than the emission control certification levels. The current study uses a roadside remote sensing emission monitoring campaign to investigate (a) fraction of high emitters in the light-duty vehicle (LDV) fleet and their contributions to the total emissions, (b) emission inspection (I/M) programs' effectiveness, and (c) alternate fuel (natural gas) encouragement policy. LDVs consist of passenger or freight transport vehicles with four wheels equivalent to classes M1 and N1 of European union vehicle classifications. The motivation is to assess the current emission inspection... 

    A systematic review of land use regression models for volatile organic compounds

    , Article Atmospheric Environment ; Volume 171 , 2017 , Pages 1-16 ; 13522310 (ISSN) Amini, H ; Yunesian, M ; Hosseini, V ; Schindler, C ; Henderson, S. B ; Künzli, N ; Sharif University of Technology
    Various aspects of land use regression (LUR) models for volatile organic compounds (VOCs) were systematically reviewed. Sixteen studies were identified published between 2002 and 2017. Of these, six were conducted in Canada, five in the USA, two in Spain, and one each in Germany, Italy, and Iran. They were developed for 14 different individual VOCs or groupings: benzene; toluene; ethylbenzene; m-xylene; p-xylene; (m/p)-xylene; o-xylene; total BTEX; 1,3-butadiene; formaldehyde; n-hexane; total hydro carbons; styrene; and acrolein. The models were based on measurements ranging from 22 sites in El Paso (USA) to 179 sites in Tehran (Iran). Only four studies in Rome (Italy), Sabadell (Spain),... 

    Seasonal variations in the oxidative stress and inflammatory potential of PM2.5 in Tehran using an alveolar macrophage model; The role of chemical composition and sources

    , Article Environment International ; Volume 123 , 2019 , Pages 417-427 ; 01604120 (ISSN) Al Hanai, A. H ; Antkiewicz, D. S ; Hemming, J. D. C ; Shafer, M. M ; Lai, A. M ; Arhami, M ; Hosseini, V ; Schauer, J. J ; Sharif University of Technology
    Elsevier Ltd  2019
    The current study was designed to assess the association between temporal variations in urban PM2.5 chemical composition, sources, and the oxidative stress and inflammatory response in an alveolar macrophage (AM) model. A year-long sampling campaign collected PM2.5 samples at the Sharif University in Tehran, Iran. PM-induced reactive oxygen species (ROS) production was measured both with an acellular dithiothreitol consumption assay (DTT-ROS; ranged from 2.1 to 9.3 nmoles min−1 m−3) and an in vitro macrophage-mediated ROS production assay (AM-ROS; ranged from 125 to 1213 μg Zymosan equivalents m−3). The production of tumor necrosis factor alpha (TNF-α; ranged from ~60 to 518 pg TNF-α m−3)...