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A coupled CFD simulation approach for investigating the pyrolysis process in industrial naphtha thermal cracking furnaces

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Chinese Journal of Chemical Engineering 2022年第4期35卷 528-542页

作者： Mohsen Rezaeimanesh ali asghar Ghoreyshi S.M.Peyghambarzadeh seyed Hassan Hashemabadi Chemical Engineering Department Babol Noshirvani University of TechnologyShariati Ave.47148-71167 BabolIran Department of Chemical Engineering Mahshahr BranchIslamic Azad UniversityMahshahrIran Computational Fluid Dynamics(CFD)Research Laboratory School of ChemicalPetroleum and Gas EngineeringIran University of Science and Technology(IUST)TehranIran

In the steam thermal cracking of naphtha,the hydrocarbon stream flows inside tubular reactors and is exposed to flames of a series of burners in the *** this paper,a full three-dimensional computational fluid dynamics(CFD)model was developed to investigate the process variables in the firebox and reactor coil of an industrial naphtha *** comprehensive CFD model consists of a standard k-εturbulence model accompanied by a molecular kinetic reaction for cracking,detailed combustion model,and radiative *** order to improve the steam cracking performance,the model is solved using a proposed iterative *** respect to temperature,product yield and specially propylene-toethylene ratio(P/E),the simulation results agreed well with industrial data obtained from a mega olefin plant of a petrochemical *** deviation of P/E results from industrial data was less than 2%.The obtained velocity,temperature,and concentration profiles were used to investigate the residence time,coking rate,coke concentration,and some other *** coke concentration at coil exit was1.9×10^(-3)%(mass)and the residence time is calculated to be 0.29 *** results can be used as a scientific guide for process engineers.

关键词： Naphtha thermal cracking CFD modeling Systems engineering Residence time Product yield

Synthesis and Characterization of Novel Castor Oil-Based Polyol for Potential Applications in Coatings

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Journal of Renewable Materials 2019年第1期7卷 31-40页

作者： Azam Sardari ali asghar Sabbagh Alvani seyed Reza Ghaffarian Color&Polymer Research Center(CPRC) Amirkabir University of TechnologyTehran158754413Iran Department of Polymer Engineering and Color Technology Amirkabir University of TechnologyTehran158754413Iran Advanced Materials Group Iranian Color Society(ICS)***TehranIran

In this study,three sorts of polyols were successfully synthesized from castor oil using a Dean-Stark quick,eco-friendly and high-efficiency *** this purpose,castor oil was epoxidized in the presence of two types of catalysts includingγ-alumina and formic acid,named as ECOAl and ECOF,*** castor oils were then characterized by use of hydrogen nuclear magnetic resonance(H-NMR)and oxirane oxygen content *** relative percentages of conversion double bond to oxirane were obtained 96% and 74% for ECOAl and ECOF,*** opening reaction of ECOAl was performed by two types of saponified castor oil as well as castor oil in a system equipped with Dean–Stark *** synthesized polyols were characterized by attenuated total reflectance-Fourier transform infrared spectroscopy(ATR-FTIR),gel permeation chromatography(GPC),differential scanning calorimetry(DSC),viscometer and OH number *** material obtained in this research is a candidate to be intended in synthesis of polyurethane for coating applications.

关键词： Castor oil dean-Stark polyol epoxidation

Modified unilateral periureteral injection technique in the treatment of patients with high-grade vesicoureteral reflux: A study of primary findings

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Asian Journal of Urology 2023年第1期10卷 96-100页

作者： seyed Alaeddin Asgari Afshin Safaei-Asl Mandana Mansour-Ghanaie seyed Mohammad Asgari asghar Faryabi Mohammadreza Bazli Faezeh Emami Sigaroudi seyed Ahmad Naseri Alavi Urology Research Center Razi HospitalSchool of MedicineGuilan University of Medical SciencesRashtIran School of Medicine Guilan University of Medical SciencesRashtIran Faculty of Medicine Tabriz University of Medical SciencesTabrizIran

Objective:Although endoscopic treatment has been used by many pediatric urologists for the treatment of vesicoureteral reflux(VUR),it has no considerable success in high-grade *** aimed to describe the primary outcomes of unilateral periureteral injection technique(PIT),as well as bilateral PIT in high-grade ***:In this prospective study,we examined 92 ureters in 45 boys and 40 girls from February 2010 to May *** PIT and unilateral PIT were applied in 67 and 25 refluxing units,*** the unilateral PIT,the subureteral injection site was only at the 5-or 7-o’clock ***,in the bilateral PIT,the subureteral injection sites were at 5-and 7-o’clock ***-and post-operative reflux grades were evaluated by voiding cystourethrography 6 months after ***:Seven patients had bilateral ***,75(81.5%)ureters showed Grade IV VUR,while 17(18.5%)had primary Grade V *** mean age of the subjects was 39.2 *** unilateral PIT ureters,VUR was resolved in 23(92.0%)refluxing *** was downgraded to Grade III in one ureter(4.0%)and to Grade II in another ureter(4.0%).In addition,in bilateral PIT cases,VUR was resolved in 60(89.6%)ureters;it downgraded to Grades II and III in 3(4.5%)and 4(6.0%)refluxing units,***:Unilateral PIT can be highly effective in the treatment of selected ureters of high-grade ***,further studies are needed to confirm our results.

关键词： Periureteral injection technique Bilateral periureteral injection technique Unilateral periureteral injection technique Endoscopy Vesicoureteral reflux

Estimation of aboveground tree carbon stock using SPOT-HRG data (a case study: Darabkola forests)

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Journal of Forestry Research 2017年第6期28卷 1172-1179页

作者： Masoumeh Fatholahi asghar Fallah seyed Mohammad Hojjati Siavash Kalbi Department of Natural Resource Sari University of Agricultural Sciences and Natural Resources SariMazandaran 48151 Iran

Forests are among the most important carbon sinks on earth. However, their complex structure and vast areas preclude accurate estimation of forest carbon *** sets from forest monitoring using advanced satellite imagery are now used in international policy *** sets enable tracking of emissions of COinto the atmosphere caused by deforestation and other types of land-use changes. The aim of this study is to determine the capability of SPOT-HRG Satellite data to estimate aboveground carbon stock in a district of Darabkola research and training forest, Iran. Preprocessing to eliminate or reduce geometric error and atmospheric error were performed on the images. Using cluster sampling, 165 sample plots were taken. Of 165 plots, 81 were in natural habitats, and 84 were in forest plantations. Following the collection of ground data, biomass and carbon stocks were quantified for the sample plots on a per hectare basis. Nonparametric regression models such as support vector regression were used for modeling purposes with different kernels including linear, sigmoid, polynomial, and radial basis *** results showed that a third-degree polynomial was the best model for the entire studied areas having an root mean square error, bias and accuracy, respectively, of 38.41,5.31, and 62.2; 42.77, 16.58, and 57.3% for the best polynomial for natural forest; and 44.71, 2.31, and 64.3%for afforestation. Overall, these results indicate that SPOTHRG satellite data and support vector machines are useful for estimating aboveground carbon stock.

关键词： Aboveground carbon stock Support vector machine SPOT-HRG Darabkola

Effects of geometric design of forest road and roadside vegetation on traffic noise reduction

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Journal of Forestry Research 2016年第2期27卷 463-468页

作者： seyed Ata Ollah Hosseini Seyran Zandi asghar Fallah Mehran Nasiri Department of Forestry and Forest Economics Faculty of Natural Resources University of Tehran Department of Forestry Faculty of Natural Resources Sari University of Agricultural Sciences and Natural Resources Alborz Road Development and Construction Corporation Civil Engineers office

Geometric design of forest roads and design of their landscapes can reduce noise pollution and its harmful effects on human health. We investigated the effects of technical and biological parameters such as geometric road design and various roadside tree stands on reducing noise pollution according to the tree density and distance from roadway in Darabkola Forests, Sari, Iran. We recorded the noise generated by a car （Land Rover） relative to changes in longitudinal slope, horizontal curve radius and type of road pavement. We also measured noise levels according to roadside tree density and stand type （coniferous and hardwood） in 40 rectangular plots of three widths （25, 100 and 300 m） and 50 m length that were randomly demar- cated along forest roads. The changes in noise level were recorded using a decibel meter with an accuracy of q-1.5 dB and resolution of 0.1 dB. Noise levels were higher alongside unpaved roads than alongside paved roads. There was an inverse relationship between the measured noise level and horizontal curve radius. The rate of noise level on horizontal curve with a radius less than 30, 30-45 m and more than 45 m were 64.8, 70.8 and 75.9 dB, respectively. The noise level increased with the increasing longitudinal slope of the road. There was a significant difference between the noise level on slopes less than 3 % （67 dB） and 3-8 % （71.2 dB） in comparison with slopes greater than 8 % （77.8 dB）, （p 〈 0.05）. Pinus brutia L. reduced the noise level more （about 6 dB） in stands of 1/3 density of mixed hardwoods within 25 m from middle of the road. Careful design of geometric properties of forest roads as well as planting coniferous trees with hardwoods is a suitable solution for reducing noise pollution.

关键词： Forest road Noise pollution Noise level Vegetation Distribution

Impact of land-use management on nitrogen transformation in a mountain forest ecosystem in the north of Iran

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Journal of Forestry Research 2013年第1期24卷 115-119页

作者： Maryam Asadiyan seyed Mohammad Hojjati Mohammad reza Pourmajidian asghar fallah Sari Agricultural Sciences and Natural Resources University Sari-Iran.

Soil inorganic N is one of the most important soil quality indexes, which may be influenced by land-use change. The historical conversion of land-use from native vegetation to agriculture resulted in sharp declines in soil N dynamics. This study was conducted to determine the soil inorganic N concentrations and net N mineralization rate in four common types of land-uses in the mountain forest area in the north of Iran, namely arable land, pine plantation, ash plantation, and beech stand. The soil samples were taken from top mineral soil layer （5 cm） in each site randomly （n=6） during August- September 2010. Beech stand and ash plantation showed significantly higher total nitrogen compared with arable land and pine plantation, while extractable NH4 ＋-N concentration was significantly greater in Beech stand compare to arable soils （p〈0.05）. No significantly difference was found in Net N mineralization, net nitrification and net ammonification rates among different land-uses. Results showed that net N mineralization and ammonification were occurred just in the soil of Ash plantation during the incubation time. Our findings suggested that conversion of Hyrcanian forests areas to pine plantation and agricultural land can disrupt soil natural activities and affect extremely soil quality.

关键词： soil quality net N mineralization nitrogen dynamic land use Hyrcanian forest Alandan.

Estimation of conservation value of myrtle(Myrtus communis)using a contingent valuation method:a case study in a Dooreh forest area,Lorestan Province,Iran

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Forest Ecosystems 2016年第1期3卷 26-36页

作者： Neda Amiri seyed F.Emadian asghar Fallah Kamran Adeli Hamid Amirnejad department of forestry sari agricultural and natural resource universitySariIran department of forest sciences gorgan agricultural and natural resource universityGorganlran department of forestry college of natural resourcessari agricultural sciences and natural resources universitySariIran department of forestry faculty of agriculturaluniversity of lorestanlorestanIran department of agricultural economics sari agricultural and natural resource universitySariIran

Background： Around 2000 plant species occur naturally in Lorestan Province of which 250 species are medicinal and myrtle is one of them. Myrtle is a shrub whose leaves and fruits have medicinal value and thus, if managed and harvested properly, could produce sustained economic benefits. In recent years, however, over half of the myrtle site areas was destroyed, due to inappropriate management and excessive harvesting practices. Thus, coming up with a practical harvesting approach along with identifying those factors damaging the sites, seems to be very crucial. Methods： In our investigation, we calculated the conservation value per hectare of myrtle in the Dooreh forest area in Lorestan Province. Using the Contingent Valuation （CV） and Double Bounded Dichotomous Choice （DBDC） methods, we determined the willingness to pay （VVTP） for myrtle conservation. The VVTP was estimated with a Iogit model for which indices were obtained based on a maximum precision criterion. Results： The results showed that 86.67 per cent of people were willing to pay for the conservation of these myrtle sites. Average monthly WTP per family was calculated as $0.79. The annual conservation value in terms of WTP for the preservation of the myrtle sites in Dooreh was estimated as $102,525. Among the variables of the model presented, education had a positive impact, while the amount proposed for payment and family size had a negative impact on the WTP. Conclusions： Our estimate of the value of myrtle conservation should provide justification for policy makers and decision making bodies of natural resources to implement policies in order to conserve the natural sites of this species more effectively.

关键词： Conservation value Myrtle Contingent valuation method Double Bounded Dichotomous method Logit model

Measurement of inter-particle forces by an interfacial force microscope

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Particuology 2010年第5期8卷 400-406页

作者： Qing Huang asghar Mesbah-Nejad seyed M. Tadayyon Peter Norton Hui Zhang Jesse Zhu Particle Technology Research Centre Department of Chemical and Biochemical Engineering The University of Western Ontario London Ontario N6A 5B9 Canada Department of Electrical and Computer Engineering The University of Western Ontario London Ontario N6A 5B9 Canada Department of Chemistry The University of Western Ontario London Ontario N6A 589 Canada

An interfacial force microscope （IFM） was employed to measure the inter-particle forces between two individual glass beads with diameters varying from 8 to 20 μm. With the feedback function of IFM turned off, attractive forces were obtained. The forces varied in the range of 0.1-0.34 μN, and their validity was confirmed by a theoretical analysis of the van der Waals force between the same glass beads. With the feedback function switched on, no attractive forces between particles were detected by the IFM when the probe approached the sample substrate. This may be attributed to the dramatic change of the attractive forces within a very short separation distance and/or the relatively poor signal-to-noise ratio of the IFM.

关键词： Inter-particle forcesvan der Waals forceInterracial force microscopeFine powder

MAC Sub-Layer Analysis with Channel Estimation in Broadband Power Line Communication

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Communications and Network 2011年第3期3卷 141-148页

作者： Mohammad Khaled Andari seyed ali asghar Beheshti 不详

Broadband power line communication (BPLC) gained a lot of interest because of low cost and high performance communication network in access area. In this paper physical (PHY) layer and medium access control (MAC) sub-layer of BPLC are considered. Furthermore, effects of bit error rate (BER) are analyzed in MAC sub-layer. Powerful turbo convolutional code (TCC) and wideband orthogonal frequency division multiplexing (OFDM) are used in PHY layer. Carrier sense multiple access (CSMA) and virtual slot multiple access (VSMA) are taken into consideration in MAC sub-layer. Multilayered perceptrons neural network with backpropagation (BP) learning channel estimator algorithm compare to classic algorithm in for channel estimating. The simulation results show that the proposed neural network estimation decreases bit error rate then in MAC sub-layer throughput increases and access delay is decreased.

关键词： BPLC Back-Propagation Neural Network (BPNN) Channel Estimation Throughput Access Delay