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Polyacrylamide hydrogel application in sand control with compressive strength testing

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Petroleum Science 2019年第1期16卷 94-104页

作者： Mahsa Baghban salehi Asefe Mousavi Moghadam Samira Zargari MarANDi Department of Petroleum Engineering Chemistry and Chemical Engineering Research Center of Iran Faculty of Chemical Engineering Tarbiat Modares University

Sand production is one of the major problems in sandstone reservoirs. Different mechanical and chemical methods have been proposed to control sand production. In this paper, we propose a chemical method based on using polyacrylamide/chromium triacetate hydrogel to investigate sand production in a synthetic sandpack system. To this end, a series of bulk experiments including the bottle test and rheological analysis along with compression tests were conducted. Experimental results indicated that the compressive strength of the sandpack was increased as much as 30 times by injecting 0.5 pore volume of hydrogel. Also, it was found that the increases in cross-linker and polymer concentrations exhibited a positive impact on the compressive strength of the sandpack, mostly by cross-linker concentration(48 psi). Hydrogel with a higher value of cross-linker could retain its viscoelastic properties against the strain which was a maximum of 122% for 0.5 weight ratio of cross-linker/polymer. The presence of salts, in particular divalent cations, has a detrimental effect on the hydrogel stability. The maximum strain value applied on hydrogel in the presence of CaCl_2 was only about 201% as compared to 1010% in the presence of distilled water. Finally, thermogravimetric analysis and its derivative showed that the hydrogel could retain its structure up to 300 °C. The results of this study revealed the potential application of the hydrogel to control sand production.

关键词： Sand control - Rheology Hydrogel strength Compressive strength Sandpack

Ultra-thin broadband solar absorber based on stadium-shaped silicon nanowire arrays

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Frontiers of Optoelectronics 2022年第1期15卷 60-72页

作者： Seyedeh Leila Mortazavifar Mohammad Reza salehi Mojtaba Shahraki Ebrahim Abiri Department of Electrical and Electronics Engineering Shiraz University of TechnologyModarres Blvd71557-13876 ShirazIran Faculty of Electrical and Electronics Engineering University of Sistan and BaluchestanDaneshgah Blvd98613-35856 ZahedanIran

This paper investigates how the dimensions and arrangements of stadium silicon nanowires(NWs)affect their absorption *** to other NWs,the structure proposed here has a simple geometry,while its absorption rate is compa-rable to that of very complex *** is shown that changing the cross-section of NW from circular(or rectangular)to a stadium shape leads to change in the position and the number of absorption modes of the *** a special case,these modes result in the maximum absorption inside *** method used in this paper to attain broadband absorption is utiliza-tion of multiple NWs which have different ***,the maximum enhancement is achieved using non-close packed *** structures can support more cavity modes,while NW scattering leads to broadening of the absorption *** the structures are optimized using particle swarm *** these optimized structures,it is viable to enhance the absorption by solar cells without introducing more absorbent materials.

关键词： Ultra-thin solar cells(SCs) Light trapping Stadium silicon nanowire(NW) Optical resonators Diffraction

Effects of Milling and Heat Treatment on the Synthesis of NiTi Powders

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Journal of Wuhan University of Technology(Materials Science) 2017年第5期32卷 1156-1162页

作者： A R Sadeghi H Mostajabodaveh A Babakhani M S Abravi A salehi Materials Research Group Iranian Academic Center for EducationCulture and Research(ACECR)Mashhad BranchP.O.Box 91779-49367MashhadIran Faculty of Metallurgical and Materials Engineering Semnan UniversityP.O.Box 35131-19111SemnanIran Department of Materials and Metallurgical Engineering School of EngineeringFerdowsi University of MashhadP.O.Box 91775-1111MashhadIran

This work reports on the production of Ni-50 at% Ti powders by a planetary ball mill in various times（0.5, 1, 2, 6, 20, 36, 54 and 120 h） and subsequent heat treatment in Ar atmosphere at 820 °C. Study of powders structure after milling and heat treatment was carried out by scanning electron microscopy and X-ray diffractometry. According to the results, after milling for 6 hours NiTi phase formed, and by the milling evolution up to 54 h, it became the dominant phase. It was found that by the milling development, a layer structure in powder particles was formed, also by increasing the milling time a more homogeneous structure was obtained. Amorphous Ni Ti transformed into ordered Ni Ti, Ni_3Ti, NiTi_2 and minor TiO_2 and TiO after heat treatment at 820 °C for 1 h.

关键词： NiTi milling amorphous heat treatment

Regenerating historical districts through tactical urbanism:A case study of Sarpol neighborhood in Isfahan Province,Iran

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Frontiers of Architectural Research 2023年第6期12卷 1234-1245页

作者： Mohammad salehi Shima Taheri Amirhosein Shabani Department of Urban Planning Najafabad BranchIslamic Azad UniversityNajafabadIran Department of Architecture Isfahan(Khorasgan)BranchIslamic Azad UniversityIsfahanIran Department of Architecture Faculty of EngineeringShahid Ashrafi Esfahani UniversityIsfahanIran Advancement in Architecture and Urban Planning Research Center Najafabad BranchIslamic Azad UniversityNajafabadIran

This paper examines historical urban fabrics’challenges regarding quality of life and visual disturbances despite their cultural and identity *** and socialoriented approaches considering social,economic,and cultural dimensions preserve and enhance these valuable *** urbanism,with its people-oriented approach,can address these *** study focused on Sarpol in Khomeinishahr County,Isfahan Province of *** city’s urban structure divides into two parts:despite its active social structure and valuable spaces,Sarpol is a historic neighborhood with significant *** followed Corbin and Strauss’s version of Grounded Theory in the qualitative research *** and snowball sampling methods were employed to select 21 participants from the Sarpol neighborhood for semi-structured *** analysis involved three stages of coding:open,axial,and *** themes included religious participation,identity,sustainable social bonds,indigenous dependence,and low environmental *** central issue identified was the crucial role of religious and cultural values as a driving force for tactical urbanism,which emerged as the most critical semantic domain related to the research problem.

关键词： Tactical urbanism Urban regeneration Historical fabrics Neighborhood Grounded theory Social-oriented approaches

Mathematical model for iron corrosion that eliminates chemical potential parameters

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Chinese Journal of Chemical Engineering 2020年第2期28卷 603-612页

作者： Hadi Seddiqi Ali Sadatshojaie Behzad Vaferi Ehsan Yahyazadeh Afshin salehi David AWood Department of Chemical and Petroleum Engineering Sharif University of TechnologyP.O.Box 11365-11155TehranIran Young Researchers and Elite Club Shiraz BranchIslamic Azad UniversityShirazIran Department of Chemistry Sharif University of TechnologyP.O.Box 11365-11155TehranIran DWA Energy Limited BassinghamLincoln LNS 9JPUnited Kingdom

Iron corrosion in acidic media is a natural phenomenon that converts elemental iron to a more chemically-stable form,*** oxide and *** this study,the iron corrosion process is modeled as a completely implicit problem,solved by a novel finite difference model to provide insight into the ionic aspects of corrosion *** new mathematical model eliminates the chemical potential parameters from the corrosion process equations,thereby reducing the need for experimental determination of chemical *** eliminatedchemical-potential-parameters model predicts and quantifies key parameters(concentrations of conjugate base ion,iron(Ⅱ)ion,hydrogen ion,anodic and cathodic potentials,and the electrical current density)associated with the iron corrosion process in acidic *** rigorous derivation and novel application of the eliminated-chemical-potential-parameters model and its results provide new insights into the iron corrosion *** present model is also applicable in any industrial process which is associated with metal *** model helps to guide the design of future corrosion resistant systems,and various experimental studies pertaining to corrosion inhibition techniques.

关键词： Finite difference modeling Implicit solution Iron corrosion process Modeling corrosion process Transient numerical simulation

Fabrication of (Ti,Hf)-rich NiTiHf Alloy Using Graphitic Mold and Crucible

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Journal of Materials Science & Technology 2014年第3期30卷 280-284页

作者： Mahdi Moshref-Javadi Majid Belbasi Seyed Hossein Seyedein Mohammad Taghi salehi School of Metallurgy & Materials Engineering Iran University of Science & Technology (IUST)

In this research, fabrication of a （Ti,Hf）-rich NiTiHf alloy by using vacuum induction melting （VIM） process and a graphitic crucible was investigated. For this purpose, casts with the nominal composition of Ni49Ti38Hf15 were prepared in graphitic crucible and mold. Optical microscopy （OM）, scanning electron microscopy （SEM）, energy dispersive X-ray spectroscopy （EDS）, X-ray diffraction （XRD）, and differential scanning calorimetry （DSC） tests were employed to characterize the samples. Results demonstrated that microstructure of the first cast was composted of a B2 austenite phase as well as a great amount of two differently formed （Ti,Hf）C carbides. Moreover, no austenite ＊-＊ martensite transformation peak was detected in the DSC curve of this sample, indicating a drastic decline in the transformation temperatures. In the succeeding cast, however, owing to the formation of carbide layers on the inner surfaces of the graphitic crucible and mold during the initial casting process, the amounts of carbides decreased remarkably. This cast exhibited transformation temperatures above 100℃, while XRD pattern denoted the presence of B19t monoclinic martensite phase at room temperature. All in all, results confirmed that VIM process using graphitic mold and crucible can be considered as an appropriate method for the fabrication of （Ti,Hf）-rich NiTiHf high temperature shape memory alloys.

关键词： High temperature shape memory alloys NiTi Martensite Casting Transformation temperatures Microstructure

Effect of Pearlite Interlamellar Spacing on Predominant Abrasive Wear Mechanism of Fully Pearlitic Steel

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材料热处理学报 2004年第5B期25卷 1207-1213页

作者： J. Ahmadi M. Monirvaghefi M. salehi B. Niroumand Merat poolad engineering company Isfahan IranIsfahan University of Technology Department of materials engineering Isfahan IranIsfahan University of Technology Department of materials engineering Isfahan IranIsfahan University of Technology Department of materials engineering Isfahan Iran

The aim of this investigation was the determination of the predominant wear mechanism on three-body abrasion of fully pearlitic low alloy steel. Furthermore, the effect of pearlite interlamellar spacing on wear behavior was investigated. For this purpose, the samples were subjected to the different heat treating to attaining different interlamellar spacing. Mechanical properties such as hardness, yield strength, tensile strength, elongation, and impact toughness were evaluated. Three body abrasion tests were conducted under ASTM standard condition using a rubber wheel abrasion test apparatus. Abraded surface and wear debris were investigated by light optical microscopy and scanning electron microscopy. The results showed that wear resistance of fully pearlitic steel depended to pearlite interlamellar spacing the and lower spacing has the greater wear resistance, so it may be due to subsurface work hardening and interlamellar spacing and cementite in fine and/or coarse pearlite, that influence on surface destruction during wear. Although during wear process the several mechanisms play roles, but study of surface and debris shows that with decreasing interlamellar spacing, the predominant mechanism wear changed from ploughing to cutting mode.

关键词：层间距珠光体三体磨损钢

Conceptual Design Process for LEO Satellite Constellations Based on System Engineering Disciplines

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Computer Modeling in Engineering & Sciences 2022年第5期131卷 599-618页

作者： Ali salehi Mahdi Fakoor Amirreza Kosari Seyed Mohammad Navid Ghoreishi Faculty of New Sciences and Technologies University of TehranTehranIran

Satellite design process is an interdisciplinary subject in which the need for collaboration among various science and engineering disciplines is ***,finding an optimal process for conceptual design of a satellite,which can optimize time and cost,is still an important *** this paper,based on system engineering approach,an optimal design process is proposed for LEO satellite *** the proposed method,design process,design sequences,and data flow are *** this regard,the conceptual design process is divided into two levels of mission(or constellation)and system(or satellite)as well as 15 main activities based on the mission profile,previous experiences of the authors,and existing ***,the relationships between these activities have been determined by considering the importance of relationships according to their ***,these relations are optimized based on design structure matrix(DSM).By utilizing this approach,system design process of a telecommunication satellite constellation in LEO is formulated in conceptual design *** and capability of the proposed approach in optimal design process of the satellite constellation are investigated by comparing the outcome with existing results in the literature.

关键词： Satellite constellation system engineering design structure matrix conceptual design

Recent progress and perspectives in additive manufacturing of magnesium alloys

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Journal of Magnesium and Alloys 2022年第6期10卷 1511-1541页

作者： Zhuoran Zeng Mojtaba salehi Alexander Kopp Shiwei Xu Marco Esmaily Nick Birbilis College of Engineering and Computer Science Australian National UniversityACT.2601 Australia Additive Manufacturing Group Singapore Institute of Manufacturing Technology(SIMTech)Agency forScienceTechnology and Research(A∗STAR)73 Nanyang Drive637662 Singapore Meotec GmbH Philipsstr.8AachenGermany State Key Laboratory of Advanced Design and Manufacturing for Vehicle Body Hunan UniversityChangsh1410082 China Department of Materials Science and Engineering Massachusetts Institute of TechnologyCambridgeMA 02139United States of America Volvo Materials Technology Laboratory Volvo GroupLundbyGothenburg 41715Sweden

Magnesium alloys remain critical in the context of light-weighting and advanced devices. The increased utilisation of magnesium(Mg)each year reveals growing demand for its Mg-based alloys. Additive manufacturing(AM) provides the possibility to directly manufacture components in net-shape, providing new possibilities and applications for the use of Mg-alloys, and new prospects in the utilisation of novel physical structures made possible from ‘3D printing’. The review herein seeks to holistically explore the additive manufacturing of Mg-alloys to date, including a synopsis of processes used and properties measured(with a comparison to conventionally prepared Mg-alloys). The challenges and possibilities of AM Mg-alloys are critically elaborated for the field of mechanical metallurgy.

关键词： Magnesium Additive manufacturing Microstructure 3D printing Mechanical properties Electrochemical properties