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Change of the mode of failure by interface friction and width-to-height ratio of coal specimens

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Journal of Rock Mechanics and Geotechnical Engineering 2015年第3期7卷 256-265页

作者： Gamal rashed Syd S.Peng Department of Mining Engineering West Virginia University

Bumps in coal mines have been recognized as a major hazard for many years. These sudden and violent failures around mine openings have compromised safety, ventilation and access to mine *** studies showed that the violence of coal specimen failure depends on both the interface friction and width-to-height（W/H） ratio of coal specimen. The mode of failure for a uniaxially loaded coal specimen or a coal pillar is a combination of both shear failure along the interface and compressive failure in the coal. The shear failure along the interface triggered the compressive failure in coal. The compressive failure of a coal specimen or a coal pillar can be controlled by changing its W/H ratio. As the W/H ratio increases, the ultimate strength increases. Hence, with a proper combination of interface friction and the W/H ratio of pillar or coal specimen, the mode of failure will change from sudden violent failure which is brittle failure to non-violent failure which is ductile failure. The main objective of this paper is to determine at what W/H ratio and interface friction the mode of failure changes from violent to non-violent. In this research, coal specimens of W/H ratio ranging from 1 to 10 were uniaxially tested under two interface frictions of 0.1 and 0.25, and the results are presented and discussed.

关键词： Bump Burst Coal strength Violent failure Width-to-height(W/H) ratio Interface friction Stressestrain curve

Effect of salts and their interaction with ingenious surfactants on the interfacial tension of crude oil/ionic solution

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Chinese Journal of Chemical Engineering 2020年第1期28卷 224-235页

作者： Mostafa Lashkarbolooki Roohollah Parvizi Shahab Ayatollahi ebrahim Ghaseminejad Raeeni School of Chemical Engineering Babol Noshirvani University of TechnologyBabolIran Department of Chemical Engineering Islamic Azad UniversityIran School of Chemical and Petroleum Engineering Sharif University of TechnologyTehranIran National Iranian South Oil Company Iran

Understanding the roles of asphaltene and resin as natural surfactants existed in crude oil can enlighten contradicting reported results regarding interfacial tension(IFT) of crude oil/aqueous solution as a function of salinity and ion type. In this way, this study is aimed to investigate the effect of these natural surface active agents on IFT of with special focus on SO4^2-anion and Mg^2+cation. Two different synthetic oil solutions of 8 wt% of the extracted asphaltene and resin dissolved in toluene are prepared, and then IFT values are measured. After that,the obtained results are compared with the IFT of intact crude oil in contact with the same saline solutions examined in the previous stage. The obtained results showed a synergistic effect of Na2SO4+ MgCl2 solution unlike the MgSO4+ MgCl2 and CaSO4+ MgCl2 solutions on IFT reduction of resin at MgCl2 concentration of 15000 mg·kg^-1. In summary, it is found that the affinity of asphaltene molecules towards the interface of oleic phase/ionic solution leads to higher IFT variation.

关键词： IFT Resin Asphaltene Mg^2+ SO4^2-

Silica-bonded N-propylsulfamic acid as a recyclable catalyst for the synthesis of 2,3-dihydroquinazolin-4(1H)-ones

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Chinese Chemical Letters 2011年第1期22卷 69-72页

作者： Khodabakhsh Niknam Nasrolah Jafarpour ebrahim Niknam Department of Chemistry Islamic Azad UniversityGachsaran BranchGachsaranIran

2,3-Dihydroquinazolin-4（1H）-one derivatives are synthesized via a one-pot, three component reaction of isatoic anhydride and an aromatic aldehyde with ammonium acetate or primary amine catalyzed by silica-bonded N-p... 详细信息

关键词： Silica-bonded N-propylsulfamic acid 2,3-Dihydroquinazolin-4(1H)-ones Isatoic anhydride Aldehydes

Facile synthesis of nanoporous CuS nanospheres for high-performance supercapacitor electrodes

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Journal of Energy Chemistry 2017年第4期26卷 762-767页

作者： Hamid Heydari Seyyed ebrahim Moosavifard Mohammad Shahraki Saeed Elyasi Faculty of Sciences Razi UniversityKermanshahIran Young Researchers and Elite Club Central Tehran BranchIslamic Azad UniversityTehranIran Department of Chemistry University of Sistan and BaluchestanZahedanIran Department of Chemical Engineering Sharif University of TechnologyTehranIran

In recent years, development of high-performance supercapacitor electrode materials has stimulated a great deal of scientific research. The electrochemical performance of a supercapacitor strongly depends on its material structures. Herein, we report a simple strategy for high-performance supercapacitors by building pseudocapacitive CuS nanospheres with nanoporous structures, nanosized walls（<10 nm） and relatively large specific surface area of 65 m;/g. This electrode demonstrates excellent electrochemical performance including a maximum specific capacitance of 814 F/g at 1 A/g, significant rate capability of 42% capacitance retention at an ultrafast rate of 50 A/g, and outstanding long-term cycling stability at various current densities. The remarkable electrochemical performance of as-prepared nanoporous CuS nanospheres electrode has been attributed to its unique structures that plays a key role in providing short ion and electron diffusion pathways, facilitated ion transport and more active sites for electrochemical reactions. This work sheds a new light on the metal sulfides design philosophy, and demonstrates that nanoporous CuS nanospheres electrode is a promising candidate for application in high-performance supercapacitors.

关键词： Supercapacitor Nanoporous CuS Nanospheres

Thermodynamic analysis of combined reforming process using Gibbs energy minimization method: In view of solid carbon formation

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Journal of Natural Gas Chemistry 2012年第6期21卷 694-702页

作者： Behzad Nematollahi Mehran Rezaei ebrahim Nemati Lay Majid Khajenoori Catalyst and Advanced Materials Research Laboratory Chemical Engineering Department Faculty of Engineering University of Kashan Institute of Nanoscience and Nanotechnology University of Kashan Energy Research Institute University of Kashan

Thermodynamic analysis was applied to study combined partial oxidation and carbon dioxide reforming of methane in view of carbon formation. The equilibrium calculations employing the Gibbs energy minimization were performed upon wide ranges of pressure （1-25 atm）, temperature （600-1300 K）, carbon dioxide to methane ratio （0-2） and oxygen to methane ratio （0-1）. The thermodynamic results were compared with the results obtained over a Ru supported catalyst. The results revealed that by increasing the reaction pressure methane conversion decreased. Also it was found that the atmospheric pressure is the preferable pressure for both dry reforming and partial oxidation of methane and increasing the temperature caused increases in both activity of carbon and conversion of methane. The results clearly showed that the addition of O2 to the feed mixture could lead to a reduction of carbon deposition.

关键词： combined reforming carbon deposition chemical equilibrium Gibbs energy minimization method thermodynamic analysis

Synthesis, characterization and TL properties of SrSO_4:Dy,Tb nanocrystalline phosphor

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Journal of Rare Earths 2014年第11期32卷 1003-1009页

作者： Khadijeh Rezaee ebrahim Saraee Amin Aghay Kharieky Maryam Erfani Department of Nuclear Engineering Faculty of Advance Sciences and Technologies University of Isfahan Department of Physics Faculty of Science University Putra Malaysia

SrSO4：Dy,Tb nanocrystalline with crystalline size in the range of 44-54 nm was prepared by co-precipitation method followed by thermal treatment and characterized by X-ray diffraction （XRD）, scanning electron microscopy （SEM）, energy dispersive X-ray spectroscopy （EDX） and UV-visible spectrometry. Our results provided direct evidence of incorporation of impurities into nanocrystalline SrSO4. The thermoluminescence （TL） properties of SrSOn：Dy,Tb nanocrystalline pellets irradiated with gamma rays at different doses were studied. The TL glow curve of SrSOa：Dy,Tb nanocrystalline pellets had a prominent peak at around 490 K and a small peak at around 430 K. The major peak in the TL glow curve was almost resolved from other peaks, which was analyzed using Chen＇s peak shape method to determine the TL kinetic parameters such as activation energy, E and kinetic order, b. The intensity of main dosimetric peak of SrSO4：Dy,Tb nanocrystalline pellets at around 490 K increased linearly with the increase in gamma dose. The TL response was linear in the range of 0.1-7 kGy. These properties made it a candidate as a dosimeter to be used for estimating the high dose of gamma rays.

关键词： high dose nanocrystalline SrSO4:Dy,Tb thermoluminescence rare earths

A Novel Image Categorization Strategy Based on Salp Swarm Algorithm to Enhance Efficiency of MRI Images

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Computer Modeling in Engineering & Sciences 2019年第4期119卷 185-205页

作者： Mohammad Behrouzian Nejad Mohammad ebrahim Shiri Ahmadabadi Department of Computer Engineering Borujerd BranchIslamic Azad UniversityBorujerdIran Department of Mathematics and Computer Science AmirkabirUniversityTehranIran

The main target of this paper is presentation of an efficient method for MRI images classification so that it can be used to diagnose patients and *** classification is one of the prominent subset topics of machine learning and data mining that the most important image technique is the auto-categorization of *** images with high resolution and appropriate accuracy allow physicians to decide on the diagnosis of various diseases and treat *** auto categorization of MRI images toward diagnosing brain diseases has been being used to accurately diagnose hospitals,clinics,physicians and medical research *** this paper,an effective method is proposed for categorizing MRI images,which emphasizes the classification *** this method,images have been firstly collected and tagged,and then the discrete wavelet transform method has been implemented to extract the relevant *** the ready features in a matrix will be subsequently held,and PCA method has been applied to reduce the features ***,a new model using support vector machine classifier with radial basis function kernel ***+RBF has been *** SVM Algorithm must bimanually initialized,while,these values have been automatically entered into the SVM classifier by Salp Swarm Algorithm(SSA):Due to high performance of SSA in fast and accurate solution of nonlinear problem as compared to other optimization algorithms,it has been applied to optimally solve the designed ***,after applying the optimal parameters and SVM classification training,the test data has been utilized and *** results have transparently suggested the effectiveness of the proposed method in the Accuracy criteria with 0.9833,the Sensitivity with 1,Specificity with 0.9818 and Error with 0.0167 in best iteration as compared to the conventional SVM method.

关键词： Image classification optimization algorithm SVM RBF SSA

Optimizing and slope determination of final wall for Maiduk Mine with consideration of destabilizer factors

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矿业科学技术学报：英文版 2016年第3期26卷 501-509页

作者： Shamsoddin Saeed Masoud Maarefvand Parviz Yaaghubi ebrahim Geotechnical Engineer Mahyar Haffar Karmania Company Department Mining & Metallurgy Amirkabir University of Technology

In this research, determination of final slope for Maiduk copper mine of Kerman is investigated according to destabilizing factors of the mine. The development of the Maiduk Mine caused the extension of the mine area and also withdrawal of its wall. So, optimizing possibility of mine slope is essential. Finally,the magnitude of optimized slopes for different walls of the mine in association with executive commands with better factors of safety is provided. The results show that the most important destabilizer factors are the presence of water and pore pressure in the faults and the main joints. With the omission of pore pressure, mine wall for the designed depth is quite stable. This requires a drainage pattern in the lifetime of the mine. In an optimistic point of view, the minimum factor of safety of the wall will be 2.81 even without drainage. This conclusion allows optimizing the slope to its maximum magnitude of 51 degree. With the pessimistic engineering judgment and with the higher SF, the magnitude of the slope is optimized to 47 degree.

关键词：稳定因素最终边坡优化孔隙水压力矿山开发矿山边坡孔隙压力设计深度

Sustainability assessment of potato fields using the DEXi decision support system in Hamadan Province, Iran

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Journal of Integrative Agriculture 2018年第11期17卷 2583-2595页

作者： Mohammed ebrahim Rezaei Morteza Barmaki Hadi Veisi Department of Agronomy and Plant Breeding University of Mohaghegh Ardabili Environmental Sciences Research Institute Shahid Beheshti University

Potato is a staple food crop and the most important agricultural commodity, which critically affects food security and economic stability in Hamadan Province, Iran. Ex-ante sustainability appraisal of new cropping systems and their comparisons with conventional systems can increase the efficiencies of innovations and changes within the production process. This study aimed to explore the sustainability levels of potato cropping systems in Hamadan Province, Iran. To this end, DEXi methodology was developed for the sustainability assessment of the cropping systems. For assessing the three dimensions of environmental, economic, and social sustainability in the four systems of traditional potato system （TPS）, Quasi-industrial potato system （QIPS）, industrial potato system （IPS）, and government-promoted potato system （GPPS）, five groups of features were utilized：（1） irrigation method; （2） seed placement; （3） farm machinery use; （4） agrochemical use; and （5） rotation. The impact a^sessments of the cropping systems were based on two, three, and two groups of ecological, social, and economic indicators, respectively. Employment, supply chain, protection, operational difficulty, productivity, profitability, input use, and biodiversity resulted in 21 basic indicators and 13 aggregated indicators, by which the cropping systems were described. The results revealed that GPPS with distinctive economic and social profiles could have a better overall sustainability despite the fact that some indicators like biodiversity could be negatively affected. Finally, three strategies were recommended for the sustainability of GPPS as follows： biodiversity enhancement, input substitution, and integrated water management.

关键词： agricultural sustainability multi-criteria potato