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A new analytical solution for calculation the displacement and shear stress of fully grouted rock bolts and numerical verifications

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International Journal of Mining Science and Technology 2016年第6期26卷 1073-1079页

作者： Ghadimi mostafa Shariar Koroush Jalalifar Hossein Department of Mining Engineering Science and Research Branch Islamic Azad University Tehran *** Iran Faculty of Mining Metallurgy and Petroleum Engineering Amir Kabir University of Technology Tehran 158754413 Iran Department of Petroleum and Mining Engineering Shahid Bahonar University of Kerman Kerman *** Iran

In presence of difficult conditions in coal mining roadways, an adequate stabilization of the excavation boundary is required to ensure a safe progress of the construction. The stabilization of the roadways can be improved by fully grouted rock bolt, offering properties optimal to the purpose and versatility in use. Investigations of load transfer between the bolt and grout indicate that the bolt profile shape and spacing play an important role in improving the shear strength between the bolt and the surrounding strata. This study proposes a new analytical solution for calculation displacement and shear stress in a fully encapsulated rock bolt in jointed rocks. The main characteristics of the analytical solution consider the bolt profile and jump plane under pull test conditions. The performance of the proposed analytical solution, for three types of different bolt profile configurations, is validated by ANSYS software. The results show there is a good agreement between analytical and numerical methods. Studies indicate that the rate of displacement and shear stress from the bolt to the rock exponentially decayed. This exponential reduction in displacement and shear stress are dependent on the bolt characteristics such as: rib height, rib spacing, rib width and grout thickness, material and joint properties.

关键词： Fully grouted bolt Jointed rock Displacement Shear stress

Experimental determination of gas holdup and volumetric mass transfer coefficient in a jet bubbling reactor

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Chinese Journal of Chemical Engineering 2021年第6期34卷 61-67页

作者： mostafa Abbasian-arani Mohammad Sadegh Hatamipour Amir Rahimi Chemical Engineering Department University of IsfahanIsfahanIran

The hydrodynamics and mass transfer characteristics of a lab-scale jet bubbling reactor(JBR)including the gas holdup,volumetric mass transfer coefficient and specific interfacial area were assessed experimentally investigating the influence of temperature,pH and superficial gas *** reactor diameter and height were 11 and 30 cm,*** was equipped with a single sparger,operating at atmospheric pressure,20 and 40℃,and two pH values of 3 and *** height of the liquid was 23 cm,while the superficial gas velocity changed within 0.010-0.040 m·s^(-1)*** were conducted with pure oxygen as the gas phase and saturated lime solution as the liquid *** liquid-side volumetric mass transfer coefficient was determined under unsteady-state oxygen absorption in a saturated lime *** gas holdup was calculated based on the liquid height change,while the specific interfacial area was obtained by a physical method based on the bubble size distribution(BSD)in different superficial gas *** results indicated that at the same temperature but different pH,the gas holdup variation was negligible,while the liquid-side volumetric mass transfer coefficient at the pH value of 6 was higher than that at the pH=*** a constant pH but different temperatures,the gas holdup and the liquid-side volumetric mass transfer coefficients at 40℃were higher than that of the same at 20℃.A reasonable and appropriate estimation of the liquid-side volumetric mass transfer coefficient(kla)in a pilot-scale JBR was provided which can be applied to the design and scale-up of JBRs.

关键词： Jet bubbling reactor Liquid-side volumetric mass transfer coefficient Gas holdup Specific interfacial area Experimental analysis

Novel aspects for thermal stability studies and shelf life assessment of modified double-base propellants

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Defence Technology（防务技术） 2019年第3期15卷 300-305页

作者： Sherif Elbasuney Ashraf.M. A. Elghafour mostafa Radwan Ahmed Fahd Hosam mostafa Ramy Sadek Amr Motaz School of Chemical Engineering Military Technical College Kobry El-Kobba Cairo Egypt British University in Egypt Elshrouk city Cairo Egypt

Modified DB propellants, based on energetic nitramine(RDX) were manufactured by solventless extrusion process. Thermal stability and shelf life assessment of modified DB propellant were investigated. Shelf life assessment was evaluated using Van’t Hoff’s formula and artificial aging at 70℃ up to120 days. Quantification of total heat released and heat flow with aging time was conducted using differential scanning calorimetry(DSC) and thermal activity monitoring(TAMIII) respectively. Modified DB formulation based on 20 wt % RDX demonstrated enhanced thermal stability in terms of controlled heat flow, and slow decomposition reactions at elevated temperature. This formulation demonstrated extended service life up to 56 years compared with reference formulation. These novel finding was ascribed to the high thermal stability of RDX and its compatibility with DB constituents. This manuscript shaded the light on novel and effective approach for thermal stability via monitoring thermal activity with aging.

关键词： Double-base propellant Thermal stability Artificial aging Shelf-life assessment

Measuring technical efficiency of potato production in Iran using robust data envelopment analysis

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Information Processing in Agriculture 2015年第1期2卷 6-14页

作者： mostafa Mardani Mashallah Salarpour Department of Agricultural Economics Faculty of AgricultureUniversity of ZabolZabolIran

A non-parametric method of data envelopment analysis(DEA)was applied to analyze the technical and scale efficiency of potato production in 23 Iranian *** many real applications,inputs and outputs may be *** the present study,a robust DEA(RDEA)optimization framework was used to concentrate on DEA with uncertain *** method was based on six inputs(human labor rent,land rent,diesel and machinery rent,irrigation water cost,fertilizer cost,pesticide cost)and the single output of potato gross *** proposed DEA for 23 Iranian potato-producing provinces reveals that the average technical efficiency is 90%and scale efficiency is 97%.This suggests that inefficient provinces can potentially reduce their overall costs for potato production.A Monte Carlo simulation was used to compute the conformity of the rankings from the RDEA model with reality to illustrate the importance of varying the level of efficiency for different levels of conservatism.

关键词： Non-parametric method Robust optimization Monte Carlo simulation Cost of potato production

Mass transfer coefficient in the eductor liquid-liquid extraction column

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Chinese Journal of Chemical Engineering 2021年第12期34卷 27-35页

作者： Bahare Esmaeeli Ahad Ghaemi Mansour Shirvani mostafa Hosseinzadeh School of Chemical Petroleum and Gas EngineeringIran University of Science&TechnologyNarmakTehranIran

In this research gasoil desalting was investigated from mass transfer point of view in an eductor liquid–liquid extraction column(eductor-LLE device).Mass transfer characteristics of the eductor-LLE device were evaluated and an empirical correlation was obtained by dimensional analysis of the dispersed phase Sherwood *** Results showed that the overall mass transfer coefficient of the dispersed phase and extraction efficiency have been increased by increasing Sauter mean diameter(SMD)and decreasing the nozzle diameter from 2 to 1 mm,*** effects of Reynolds number(R_(e)),projection ratio(ratio of the distance between venturi throat and nozzle tip to venturi throat diameter,Rpr),venturi throat area to nozzle area ratio(R_(th-n))and two phases flow rates ratio(R_(Q))on the mass transfer coefficient(K)were *** to the results,K increase with increasing Re and RQ and also with decreasing Rpr and R_(th-n).Semi-empirical models of drop formation,rising and coalescence were compared with our proposed empirical *** was revealed that the present model provided a relatively good fitting for the mass transfer model of drop ***,experimental data were in better agreement with calculated data with AARE value of 0.085.

关键词： Gasoil desalting Liquid-liquid extraction Eductor-LLE device Mass transfer coefficient Extraction efficiency

A critical review on the developments of rock support systems in high stress ground conditions

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International Journal of Mining Science and Technology 2020年第5期30卷 555-572页

作者： Masoud Ghorbani Korosh Shahriar mostafa Sharifzadeh Reza Masoudi Department of Mining and Metallurgical Engineering Amirkabir University of TechnologyTehranIran Key Laboratory of Ministry of Education on Safe Mining of Deep Metal Mines Northeastern UniversityShenyangLiaoning 110819China Department of Mining and Metallurgical Engineering Curtin UniversityKalgoorlieWA 6430Australia

Extreme ground behaviour in high-stress rock masses such as rockburst prone and squeezing ground conditions are encountered in a range of underground projects both in civil and mining *** occurrence of such ground behaviour types are difficult to predict and special design and construction measures must be taken to control *** the most appropriate support system in such grounds is one of the major challenges for ground control engineers because there are many contributing factors to be considered,such as the rock mass parameters,the stress condition,the type and performance of the support systems,the condition of major geological structures and the size and geometry of the underground *** main characteristics and support requirements of rockburst-prone and squeezing ground conditions are herein critically reviewed and characteristics of support functions are *** types of energy-absorbing rockbolts and other support elements applicable for ground support in burst-prone and squeezing grounds are *** differences in the choice and economics of ground support strategies in high-stress ground conditions between civil tunnels and mining excavations are *** support benchmarking data and mitigation measures for mines and civil tunnels in burst-prone,squeezing and heavily swelling grounds conditions are briefly presented by some examples in practice.

关键词： High in-situ stress Rockburst Squeezing Swelling Energy-absorbing rockbolts Yielding supports

Quantifying non-classical correlations under thermal effects in a double cavity optomechanical system

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Chinese Physics B 2020年第2期29卷 121-128页

作者： Mohamed Amazioug Larbi Jebli mostafa Nassik Nabil Habiballah Department of Physics Ecole Normale Supérieure(ENS)Mohammed V University in RabatMorocco LPHE-MS Department of PhysicsFaculty of SciencesMohammed V UniversityRabatMorocco EPTHE Department of PhysicsFaculty of SciencesIbn Zohr UniversityAgadirMorocco Faculty of Applied Sciences Ibn Zohr UniversityAit-MelloulMorocco Abdus Salam International Center for Theoretical Physics Strada Costiera1134151TriesteItaly

We investigate the generation of quantum correlations between mechanical modes and optical modes in an optomechanical system,using the rotating wave *** system is composed of two Fabry-Pérot cavities separated in space;each of the two cavities has a movable *** aim is the evaluation of entanglement between mechanical modes and optical modes,generated by correlations transfer from the squeezed light to the system,using Gaussian intrinsic entanglement as a witness of entanglement in continuous variables Gaussian states,and the quantification of the degree of mixedness of the Gaussian states using the ***,we quantify nonclassical correlations between mechanical modes and optical modes even beyond entanglement by considering Gaussian geometric discord via the Hellinger ***,entanglement,mixdness,and quantum discord are analyzed as a function of the parameters characterizing the system(thermal bath temperature,squeezing parameter,and optomechanical cooperativity).We find that,under thermal effect,when entanglement vanishes,purity and quantum discord remain ***,the Gaussian Hellinger discord is more robust than *** effects of the other parameters are discussed in detail.

关键词： cavity optomechanics quantum correlations Gaussian intrinsic entanglement purity Gaussian Hellinger discord Gaussian geometric discord

Enhanced selectivity of hydrolytic precipitation of Zn from Zn-Ni sulfate solution via chelation of Ni

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Transactions of Nonferrous Metals Society of China 2018年第12期28卷 2566-2573页

作者： mostafa Aghazadeh-Ghomi Javad Moghaddam Naghi Parvini Ahmadi Department of Materials Engineering Azarbaijan Shahid Madani University Materials and Metallurgical Engineering department University of Zanjan Faculty of Materials Engineering Sahand University of Technology

The selective precipitation of zinc from zinc-nickel sulfate solution with the Zn/Ni molar ratio of20:1was *** addition of0.5mol/L NaOH solution into the zinc-nickel sulfate solution containing0,0.01,0.02,0.03and0.04mol/L ethylene diamine tetraacetate(EDTA)as a chelating agent was *** equilibrium analysis of precipitation pathway was performed using Visual MINTEQ *** equilibrium analysis showed that the presence of small amounts of EDTA can prevent nickel precipitation in alkaline conditions without any negative effect on zinc *** this basis,more than90%of zinc could be precipitated as a product with about50%Zn and only0.11%Ni at pH=9.0merely as a result of the presence of0.03mol/L EDTA in the *** stirring time of120min after precipitation was found to be essential for more complete *** X-ray diffraction studies on the precipitate revealed that the precipitated phase was Zn4(OH)6SO4.4H2O.

关键词： zinc nickel hydrolytic precipitation separation chelate equilibrium analysis

The effect of finite duration inputs on the dynamics of a system： Proposing a new approach for cancer treatment

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International Journal of Biomathematics 2015年第3期8卷 155-173页

作者： mostafa Nazari Ali Ghaffari Center of Excellence in Robotics and Control K. N. Toosi University of Technology Pardis St. Tehran 19697 64499 Iran Mechanical Engineering DepartmentK. N. Toosi University of TechnologyPardis St. Tehran 19697 64499 Iran

In this paper, a principal question regarding the effect of inputs on the characteristics of dynamic systems is discussed. Whether an input implemented only for a limited duration, can change the characteristics of a dynamic system such that the behavior of the free system, after eliminating the input, differs from that before acting the input？ In this paper, it is shown that a limited time acted input is not able to change the dynamical properties of a system after its elimination. Regarding the proposed approach, a novel finite duration treatment method is developed for a tumor-immune system. The vaccine therapy is used to change the parameters of the system and the chemotherapy is applied for pushing the system to the domain of attraction of the healthy state. For optimal chemotherapy, an optimal control is used based on state-dependent Riccati equation （SDRE）. It is shown that, in spite of eliminating the treatment （therapeutic inputs）, the system approaches to healthy state conditions. The present analysis suggests that a proper treatment method must change the dynamics of the cancer instead of only reducing the population of cancer cells.

关键词： Cancer stability changeable dynamic properties system.