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Effect of mechanical activation on thiosulfate leaching of gold from complex sulfide concentrate

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Transactions of Nonferrous Metals Society of China 2011年第12期21卷 2744-2751页

作者： Mohsen HASHEMZADEHFINI Jana FICERIOVá emad.abkhoshk Behrouz Karimi SHAHRAKI Iran Mineral Processing Research Center Karaj Iran Institute of Geotechnics of Slovak Academy of Sciences Watsonova 4504353 Koice Slovakia Department of Mining Engineering Science and Research Branch Islamic Azad University Tehran Iran

The use of mechanical activation to enhance gold recovery from a CuPbZn complex sulfide concentrate was investigated. The effects of milling time, ball size, sample to ball ratio and milling speed on thiosulfate leaching were studied. Under optimum conditions of milling time 1 h, ball size 20 mm, sample to ball ratio 1/15 and mill speed 600 r/min, nearly 78% of sample is amorphized, particle size decreases from d100=30 μm to d100=8 μm, specific surface area increases from 1.3 m2/g to 4.6 m2/g and gold recovery enhances from 17.4 % in non-activated sample to 73.26 %.

关键词： mechanical activation thiosulfate leaching refractory ore extraction of gold

Age structure and static life tables of the endangered Juniperus phoenicea L. in North Sinai Mountains, Egypt:implication for conservation

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Journal of Mountain Science 2020年第9期17卷 2170-2178页

作者： emad A.FARAHAT Botany and Microbiology Department Faculty of ScienceHelwan UniversityCairoEgypt

Studying the population ecology of endangered plants provides important baseline information for its monitoring and *** phoenicea *** an endangered species in arid ecosystems in Africa and the Middle *** static life tables,survival curve and age structure of *** populations from two mountains in North Sinai,Egypt(Gabal(G.)El-Halal and ***-Maghara)were *** each mountain,fifteen plots were selected,and field measurements such as stand density,tree height,and crown diameter were ***,44 trees were cored and crossdated according to standard dendrochronological *** results showed that the tree ages ranged from 50 to 262 years at ***-Halal and 96 to431 years at *** *** individuals dominated the study area,with only a few individuals being younger than 100 ***,seedling recruitment was extremely *** the studied *** populations showed high mortality rates among both old and young individuals,there is an imminent need for establishing a conservation program to prevent its extinction in the ***,management and conservation efforts should be made to minimize human disturbance and protect the relic habitats of this endangered species at its southern distribution limits in Africa.

关键词： Juniperus phoenicea Age distribution Life history Mortality Endangered plant Sinai

Numerical analysis of frictional behavior of dense gas-solid systems

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Particuology 2017年第3期15卷 178-190页

作者： emad Ghadirian Hamid Arastoopour Gamma Technologies LLC. 601 Oakmont Ln Suite 220. Westmont IL 60559 USA Department of Chemical and Biological Engineering Illinois Institute of Technology. Chicago IL 60616 USA Wanger Institute for Sustainable Energy Research Illinois Institute of Technology Chicago IL 60616 USA

Dense gas-solid flows show significantly higher stresses compared with dilute flows, mainly attributable to particle-particle friction in dense particle flows. Several models developed have considered particle-particle friction; however, they generally underestimate its effect in dense regions of the gas-solid system, leading to unrealistic predictions in their flow patterns. Recently, several attempts have been made to formulate such flows and the impact of particle-particle friction on predicting flow patterns based on modified frictional viscosity models by including effects of bulk density changes on frictional pressure of the solid phase. The solid-wall boundary is also expected to have considerable effect on friction because particulate phases generally slip over the solid surface that directly affects particle-particle frictional forces. Polydispersity of the solid phase also leads to higher friction between particles as more particles have sustained contact in polydispersed systems. Their effects were investi- gated by performing CFD simulations of particle settlement to calculate the slope angle of resting material of non-cohesive particles as they settle on a solid surface. This slope angle is directly affected by frictional forces and may be a reasonably good measure of frictional forces between particles. The calculated slope angle, as a measure of frictional forces inside the system are compared with experimental values of this slope angle as well as simulation results from the literature.

关键词： Solid frictional pressure Particle-particle frictional forcesL-valve Computational fluid dynamics (CFD)Polydispersity Angle of repose

Theoretical-period characteristics of frame buildings designed under variable levels of seismicity and allowable-drift

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Earthquake Engineering and Engineering Vibration 2020年第3期19卷 669-681页

作者： Hamdy Abou-Elfath emad Elhout Structural Engineering Department Faculty of EngineeringAlexandria UniversityAlexandria 21544Egypt Higher Institute of Engineering and Technology King-MarriottAlexandriaEgypt

Period equations provided by seismic codes are generally derived by calibration with recorded period data of buildings located in high seismicity *** period-equations do not account for either the design level of seismicity or the permissible limit of lateral *** designed under high level of seismicity are expected to display higher stiffness and shorter periods than buildings designed under low-to-medium seismicity *** addition,buildings designed with high level of permissible lateral-drift are expected to display lower stiffness and longer periods than buildings designed with low level of permissible *** this study,the theoretical fundamental-periods of an ensemble of regular reinforced concrete(RC)and steel moment-resisting frame(MRF)buildings having 3-,6-,9-and 12-stories and designed with various levels of seismicity and permissible lateral-drift are *** obtained outcome indicates the sensitivity of the MRF theoretical-periods to the design seismicity and the permissible *** results also indicate the need for modifying the current period equations to realistically account for the variations in the design seismicity and allowable lateral-drift of MRF buildings.

关键词： concrete frame stiffness

Semantic Document Layout Analysis of Handwritten Manuscripts

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Computers, Materials & Continua 2023年第5期75卷 2805-2831页

作者： emad Sami Jaha Department of Computer Science Faculty of Computing and Information TechnologyKing Abdulaziz UniversityJeddah21589Saudi Arabia

A document layout can be more informative than merely a document’s visual and structural ***,document layout analysis(DLA)is considered a necessary prerequisite for advanced processing and detailed document image analysis to be further used in several applications and different *** research extends the traditional approaches of DLA and introduces the concept of semantic document layout analysis(SDLA)by proposing a novel framework for semantic layout analysis and characterization of handwritten *** proposed SDLA approach enables the derivation of implicit information and semantic characteristics,which can be effectively utilized in dozens of practical applications for various purposes,in a way bridging the semantic gap and providingmore understandable high-level document image analysis and more invariant characterization via absolute and relative *** approach is validated and evaluated on a large dataset ofArabic handwrittenmanuscripts comprising complex *** experimental work shows promising results in terms of accurate and effective semantic characteristic-based clustering and retrieval of handwritten *** also indicates the expected efficacy of using the capabilities of the proposed approach in automating and facilitating many functional,reallife tasks such as effort estimation and pricing of transcription or typing of such complex manuscripts.

关键词： Semantic characteristics semantic labeling document layout analysis semantic document layout analysis handwritten manuscripts clustering retrieval image processing computer vision machine learning

Nonlinear dynamical wave structures of Zoomeron equation for population models

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Chinese Physics B 2022年第6期31卷 235-240页

作者： Ahmet Bekir emad H M Zahran Neighbourhood of Akcaglan Imarli StreetNumber:28/426030EskisehirTurkey Departments of Mathematical and Physical Engineering Benha UniversityFaculty of EngineeringShubraEgypt

The nonlinear dynamical exact wave solutions to the non-fractional order and the time-fractional order of the biological population models are achieved for the first time in the framwork of the Paul-Painlevéapproach method(PPAM).When the variables appearing in the exact solutions take specific values,the solitary wave solutions will be easily *** realized results prove the efficiency of this technique.

关键词： (2+1)-dimensional non-fractional Zoomeron equation time-fractional biological population model Paul-Painlevéapproach method traveling wave solutions

Design of a new static solar concentrator with a high concentration ratio and a large acceptance angle based on bifacial solar cells

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Clean Energy 2023年第3期7卷 509-518页

作者： Adnan Shariah emad Hasan Physics Department Jordan University of Science and TechnologyPO Box 3030IrbidJordan

Solar concentrators are used in solar photovoltaic systems to lower the cost of producing *** this situation,fewer solar cells can be used,lowering the overall cost of the *** purpose of this article is to design,construct,install and test a stationary(non-tracking)concentrating system in Irbid,*** solar cells are used in the *** concentrator designs(with the same concentration ratio)are experimentally ***-A has a parabolic shape in the lower part but flat reflecting walls,whereas Conc-B has a standard compound parabolic shape in all *** receiving solar cells are arranged in three distinct positions in each *** results reveal that the output power from both concentrators is affected by the placement of the receiving solar cells within the *** has also been found that concentrators with flat reflecting walls perform better than those with parabolic reflecting ***-A’s power collection is~198%greater than that of a non-concentrating *** Conc-B is used,the increase in power is~181%.

关键词： bifacial solar cell non-tracking system parabolic trough concentration PV concentrators

Challenges against CO_(2) abatement strategies in cement industry: A review

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Journal of Environmental Sciences 2021年第6期33卷 84-101页

作者： emad Benhelal Ezzatollah Shamsaei Muhammad Imran Rashid Department of Chemical Engineering The University of NewcastleNew South Wales 2287Australia Department of Civil Engineering Monash UniversityClayton 3800VictoriaAustralia Chemical Polymer and Composite Materials Engineering DepartmentUniversity of Engineering and TechnologyLahore(New Campus)39021Pakistan

Cement industry is an intensive source of fuel consumption and greenhouse gases(GHGs) emissions. This industry is responsible for 5% of GHGs emissions and is among the top industrial sources of carbon dioxide(CO_(2)) emissions. Therefore, CO_(2) emissions reduction from cement production process has been always an appealing subject for researches in universities and industry. Various efforts have been carried out to mitigate the huge mass of CO_(2) emissions from the cement industry. Although, majority of these strategies are technically viable, due to various barriers, the level of CO_(2) mitigation in cement industry is still not satisfactory. Among numerous researches on this topic, only a few have tried to answer why CO_(2) abatement strategies are not globally practiced yet. This work aims to highlight the challenges and barriers against widespread and effective implementation of CO_(2) mitigation strategies in the cement industry and to propose practical solutions to overcome such barriers.

关键词： CO_(2)emissions CO_(2)mitigation Cement industry Challenges of CO_(2)reduction

Maximum entropy based finite element analysis of porous media

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Frontiers of Structural and Civil Engineering 2019年第2期13卷 364-379页

作者： emad NOROUZI Hesam MOSLEMZADEH Soheil MOHAMMADI High Performance Computing Laboratory School of Civil EngineeringFaculty of EngineeringUniversity of TehranTehranIran

The maximum entropy theory has been used in a wide variety of physical, mathematical and engineering applications in the past few years. However, its application in numerical methods, especially in developing new shape functions, has attracted much interest in recent years. These shape functions possess the potential for performing better than the conventional basis functions in problems with randomly generated coarse meshes. In this paper, the maximum entropy theory is adopted to spatially discretize the defonnation variable of the governing coupled equations of porous media. This is in line with the well-known fact that higher-order shape functions can provide more stable solutions in porous problems. Some of the benchmark problems in deformable porous media are solved with the developed approach and the results are compared with available references.

关键词： maximum entropy FEM fully coupled multi-phase system porous media