检索结果-南通市图书馆

Cadmium speciation as influenced by soil water content and zinc and the studies of kinetic modeling in two soils textural classes

在线全文

学校读者我要写书评

暂无评论

International Soil and Water Conservation Research 2020年第3期8卷 286-294页

作者： Farzad Rassaei Mehran Hoodaji seyed Ali Abtahi Department of Soil Science Isfahan(Khorasgan)BranchIslamic Azad UniversityIsfahanIran Department of Soil Science Shiraz UniversityShirazIran

Background and aims:Since few studies have existed in the literature about the effect of zinc(Zn)on cadmium(Cd)chemical forms in ***,this study has been performed to determine the impact of Zn on cadmium Cd chemical forms in two soil textural classes in Fars province-Iran at two soil water content(SWC)(flooded soil water content(FSWC)and field capacity soil water content(FCSWC))and study the kinetic modeling of *** and materials:Variables were three levels of Cd(0,30 and 60 mg kg-1 of soil as CdSO4·8H2O),three levels of Zn(0,5 and 10 mg kg-1 of soil as Zn-EDTA)three level Incubation times(2,4 and eight weeks),two soil textural classes(clay and sandy clay loam)and two *** randomized completed block design(RCBD)was used for this *** Tessier sequential extraction method was used to determine the Cd concentration in(WsEx),(Fe-MnOx),(Car),(Om)and(Res)chemical ***:In the FSWC,Zn reduced the Cd concentration in Fe-MnOx,Car and Om forms and increased the WsEx but had no significant effect on the Res *** in the Cd chemical forms under the in-fluence of Zn in both soils followed a similar *** the FCSWC,Zn reduced the Cd concentration Car and Om forms and increased the Cd concentration in the Fe-MnOx and WsEx forms while had no sig-nificant effect on Res form in the sandy clay loam *** the clay soil adding Zn reduced the Cd con-centration in Car and Om fractions and increased the Fe-MnOx and Res forms while has no significant effect on WsEx *** competitive transport and adsorption Interactions between these two ions caused the changing in the Cd concentration in its chemical *** reduces the Cd concentration in the forms which are easily released into the soil solution from where they can be absorbed by *** power function kinetic mode is the best fitted model which can describe the Cd adsorption in our soil *** clay and organic compounds control the Cd adsorption in *** higher rate of C

关键词： Cadmium Chemical forms Field capacity Flooding condition Kinetic model Sequential technique Soil water content Zinc

Experimental study of a heavy fuel oil atomization by pressure-swirl injector in the application of entrained flow gasifier

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Chinese Journal of Chemical Engineering 2019年第4期27卷 765-771页

作者： Pouria Mikaniki seyed Mohammad Ali Najafi Hojat Ghassemi School of Mechanical Engineering Iran University of Science and Technology

The available SMD(Sauter mean diameter) correlations on pressure-swirl injectors predict droplet sizing very different from each other, especially for heavy fuels. Also there was a lack in the literature for comparing available correlations. So an experimental study was conducted on a heavy fuel oil(HFO) spray, Mazut 380. A pressure swirl injector was designed and fabricated. The experiments for Mazut at 40℃ and 80℃ were compared with the results for water, including spray half cone angle, breakup length and mean droplet diameter,at different injection pressures. Lower spray angle, higher breakup length and larger droplets were observed for lower injection pressures and higher liquid viscosity. SMD was about 75 μm for water and about 87 μm for Mazut at 80℃. The results for droplet mean diameter were also compared with correlations from previous studies on pressure swirl atomizers. The SMD results show that for water spray, LISA method was in good agreement,also Babu and Ballester correlations were successful when high viscosity fluid was injected.

关键词： Atomization Pressure-swirl injector Mazut Size distribution Fuel Viscosity

Electrochemical Behavior of Passive Films Formed on the Surface of Coarse-,Fine-and Ultra-fine-Grained AA1050 Based on a Modified PDM

在线全文

学校读者我要写书评

暂无评论

Acta Metallurgica Sinica(English Letters) 2016年第7期29卷 629-637页

作者： seyed Omid Gashti Arash Fattah-alhosseini Yousef Mazaheri Department of Materials Engineering Bu-Ali Sina University

Electrochemical impedance spectroscopy （EIS） and Mott-Schottky analysis were carried out to evaluate the electrochemical behavior of the passive films formed on the surface of coarse-grained （CG）, fine-grained （FG） and ultrafine-grained （UFG） 1050 A1 alloy （AA1050） samples in alkaline media （pH value of 8.0） based on a modification of point defect model （PDM）. The EIS results revealed that the polarization resistance increased from about 22.71-120.33 kΩ cm2 for UFG sample when compared to CG sample （annealed sample）. The semiconductor properties of the passive films formed on CG, FG and UFG AA1050 samples in the test solution were investigated by employing Mott-Schottky analysis in conjunction with PDM. The results indicated that donor densities were in the range of 2.19 × 1021-0.61 × 1021 cm-3 and decreased with grain refinement. Finally, all electrochemical tests showed that the electrochemical behavior of AA1050 alloy was improved by decreasing the grain size, mainly due to the formation of thicker and less defective oxide films.

关键词： AA1050 alloy Grain refinement Ultra-fine grain (UFG) Passive film Mott-Schottky

Ga-(Nb+Ta)-(Nb/Ta)(Zr/Hf) Ternary Diagram: An Excellent Tool for Discriminating Barren and Ta-Hosting Granite-Pegmatite Systems

在线全文

学校读者我要写书评

暂无评论

Journal of Earth Science 2020年第3期31卷 551-558页

作者： Maryam Mohamadizadeh seyed Hossein Mojtahedzadeh Farimah Ayati Mining and Metallurgical Engineering Department Yazd UniversityYazd 98195-741Iran Department of Geology Payame Noor University19395-4697 TehranIran

Discriminating barren and fertile intrusions is one of the main challenges in the search for rare-element *** comprising more than one element can make discrimination of productive and barren samples more *** diagrams distinguish samples by simultaneous means of positive and/or negative correlations between variables.A ternary diagram for S-type peraluminous granites has been obtained in this ***,a database composed of Ta-bearing and barren granitic systems was created,then geochemical behavior of trace elements was studied,and statistical investigations were done using GCDkit software,which resulted in the Ga-(Nb+Ta)-(Nb/Ta)(Zr/Hf)ternary diagram which can distinguish the non-mineralized granites from productive *** Ta-bearing samples,which are situated in the fertile field in the diagram,are those which have high Nb and Ta contents,elevated Ga content and the lowest Nb/Ta and Zr/Hf values.

关键词： tantalum mineralization S-type peraluminous granite discrimination of fertile and barren granites whole-rock geochemistry indicators

A novel hybrid algorithm based on a harmony search and artificial bee colony for solving a portfolio optimization problem using a mean-semi variance approach

在线全文

学校读者我要写书评

暂无评论

Journal of Central South University 2016年第1期23卷 181-188页

作者： seyed Mohammad seyedhosseini Mohammad Javad Esfahani Mehdi Ghaffari Department of Industrial Engineering Iran University of Science and Technology Young Researchers and Elite Club Naragh BranchIslamic Azad University Department of Industrial Engineering Naragh BranchIslamic Azad University

Portfolio selection is one of the major capital allocation and budgeting issues in financial management, and a variety of models have been presented for optimal selection. Semi-variance is usually considered as a risk factor in drawing up an efficient frontier and the optimal portfolio. Since semi-variance offers a better estimation of the actual risk portfolio, it was used as a measure to approximate the risk of investment in this work. The optimal portfolio selection is one of the non-deterministic polynomial(NP)-hard problems that have not been presented in an exact algorithm, which can solve this problem in a polynomial time. Meta-heuristic algorithms are usually used to solve such problems. A novel hybrid harmony search and artificial bee colony algorithm and its application were introduced in order to draw efficient frontier portfolios. Computational results show that this algorithm is more successful than the harmony search method and genetic algorithm. In addition, it is more accurate in finding optimal solutions at all levels of risk and return.

关键词： portfolio optimizations mean-variance model mean semi-variance model harmony search and artificial bee colony efficient frontier

Modeling of Land Subsidence in the South Pars Gas Field (Iran)

在线全文

学校读者我要写书评

暂无评论

International Journal of Geosciences 2013年第7期4卷 1095-1100页

作者： Mohammad Hossein Taherynia seyed mahmoud Fatemi Aghda Akbar Ghazifard Department of Geology Faculty of Sciences Kharazmi University Tehran Iran Department of Geology Faculty of Sciences University of Isfahan Isfahan Iran

The objective of this study is to predict the subsidence of the South Pars gas field at the end of production period. With respect to the notable reservoir thickness, significant pressure drop due to extraction and high areal extent of the South Pars gas field there is a high subsidence potential in this field. In order to determinate the maximum land subsidence and subsidence profile of the South Pars gas field, at first, the reservoir compaction was estimated based on the thickness of the reservoir, the pressure drop in the reservoir and the uniaxial compaction coefficient of the reservoir rock, and then the effect of the reservoir compaction on the field surface was modeled with the use of analytical and semi-numerical methods. The compaction of the reservoir at the end of production period was estimated to be about 0.48 m. Both of the subsidence modeling methods show similar results and predict that the maximum subsidence will reach about 0.6 m at the end of production period.

关键词： Subsidence South Pars Compressibility Reservoir Rock Analytical Method Semi-Analytical Method

A generalized set of correlations for plus fraction characterization

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Petroleum Science 2012年第3期9卷 370-378页

作者： JAMIALAHMADI Mohamad ZANGENEH Hossein HOSSEINI seyed Sajad Petroleum Engineering Department Petroleum University of Technology Chemical & Petroleum Engineering Department Sharif University of Technology

The importance of accurate determination of the critical properties of plus fractions in prediction of phase behaviour of hydrocarbon mixtures by equations of state is well known in the petroleum industry. It has been stated in various papers （Elsharkawy, 2001） that using the plus fraction as a single group in equation of state calculations reduces the accuracy of the results. However in this work it has been shown that using the proper values of critical temperature and pressure for the plus fraction group can estimate the properties of hydrocarbon mixtures, and they are accurate enough to be used in reservoir engineering and enhanced oil recovery calculations. In this paper, a new method is proposed for calculating the critical properties of plus fractions of petroleum fluids. One can use this method either in predicting critical pressure and temperature of single carbon numbers （SCNs） after the splitting process or in predicting critical pressure and temperature of the plus fraction as a single group. A comparison study is performed against Riazi-Daubert correlation （Riazi and Daubert, 1987） and Sancet correlations （Sancet, 2007） for 25 oil samples taken from 14 fields from southwest Iran. The results indicate the superiority of the proposed method to the Riazi-Daubert and Sancet correlations.

关键词： Plus fraction critical properties correlation single carbon number bubble point calculations

Optimization of passive control performance for different hard disk drives subjected to shock excitation

在线全文

学校读者我要写书评

暂无评论

Journal of Central South University 2017年第4期24卷 891-899页

作者： seyed Rashid Alavi Mehdi Rahmati Saeed Ziaei-Rad Department of Mechanical Engineering Isfahan University of Technology Isfahan 84156-83111 Iran Isfahan Mathematics House Isfahan 81698-51177 Iran

Laptop personal computers(LPCs) and their components are vulnerable devices in harsh mechanical environments. One of the most sensitive components of LPCs is hard disk drive(HDD) which needs to be protected against damages attributable to shock and vibration in order to have better magnetic read/write performance. In the present work, a LPC and its HDD are modeled as two degrees of freedom system and the nonlinear optimization method is employed to perform a passive control through minimizing peak of HDD absolute acceleration caused by a base shock excitation. The presented shock excitation is considered as half-sine pulse of acceleration. In addition, eleven inequality constraints are defined based on geometrical limitations and allowable intervals of lumped modal parameters. The target of the optimization is to reach optimum modal parameters of rubber mounts and rubber feet as design variables and subsequently propose new characteristics of rubber mounts and rubber feet to be manufactured for the HDD protection against shock excitation. The genetic algorithm and the modified constrained steepest descent algorithm are employed in order to solve the nonlinear optimization problem for three widely-used commercial cases of HDD. Finally, the results of both optimization methods are compared to make sure about their accuracy.

关键词： hard disk drive passive control shock excitation sequential quadratic programming genetic algorithm rubber

Numerical study of power production from tidal energy in the Khuran Channel and its feedback on background hydrodynamics

在线全文

学校读者我要写书评

暂无评论

Acta Oceanologica Sinica 2022年第5期41卷 173-182页

作者： Davood Shariatmadari seyed Mostafa Siadatmousavi Cyrus Ershadi Civil Engineering Department Faculty of Technology and EngineeringUniversity of HormozganHormozganBandar Abbas***Iran School of Civil Engineering Iran University of Science and TechnologyTehran***Iran

This study focuses on the development of a farm of tidal turbines in the Khuran *** important factors include the location of turbines and their hydrodynamic effects on the environment.A three-dimensional circulation model for the Persian Gulf is employed for the comprehensive evaluation of the tidal energy potential throughout the study *** model is validated by using in situ observations of water level and current *** appropriate potential points for extracting the tidal energy were identified in the Persian Gulf using the model *** Khuran Channel,located in the north of Qeshm Island,was found to be the best place to extract tidal energy inside the Persian *** adding the term of momentum losses to the governing equations,the feedback of extracting energy on the hydrodynamic around Qeshm Island was *** simulation results show that the average daily power production of a tidal farm with 99 turbines for one month is approximately 1.3 *** tidal farm also has a significant impact on the water level inside the Khuran Channel,especially near the tidal farm where these fluctuations exceed 4 *** change in the current speed caused by wake reaches 0.4 m/*** effects were active up to 7 km downstream of the *** current velocity was also estimated to be 1.6 m/s and 2.1 m/s during the spring and ebb tides within the channel,respectively.

关键词： renewable energy tidal energy Khuran Channel tidal horizontal axis turbine turbine farm Delft3D