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Design and fabrication of a large-scale oedometer

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Journal of Central South University 2015年第3期22卷 931-936页

作者： Maryam Mokhtari Nader Shariatmadari ali akbar Heshmati R Hossein Salehzadeh School of Civil Engineering Iran University of Science and Technology (IUST)

The most common apparatus used to investigate the load-deformation parameters of homogeneous fine-grained soils is a Casagrande-type oedometer. A typical Casagrande oedometer cell has an internal diameter of 76 mm and a height of 19 ***, the dimensions of this kind of apparatus do not meet the requirements of some civil engineering applications like studying load-deformation characteristics of specimens with large-diameter particles such as granular materials or municipal solid waste materials. Therefore, it is decided to design and develop a large-scale oedometer with an internal diameter of 490 mm. The new apparatus provides the possibility to evaluate the load-deformation characteristics of soil specimens with different diameter to height ratios. The designed apparatus is able to measure the coefficient of lateral earth pressure at rest. The details and capabilities of the developed oedometer are provided and discussed. To study the performance and efficiency, a number of consolidation tests were performed on Firoozkoh No. 161 sand using the newly developed large scale oedometer made and also the 50 mm diameter Casagrande oedometer. Benchmark test results show that measured consolidation parameters by large scale oedometer are comparable to values measured by Casagrande type oedometer.

关键词： load-deformation parameters large-scale oedometer Casagrande-type oedometer coefficient of lateral earth pressure at rest

Structural and optoelectronic properties of CsLnZnTe_(3)(Ln=La,Pr,Nd and Sm)

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Journal of Rare Earths 2023年第3期41卷 388-396,I0003页

作者： Imad Khan Ihsan Ullah Izaz Ul Haq akbar ali A.Dahshan Zahid ali Iftikhar Ahmad Center for Computational Materials Science Department of PhysicsUniversity of MalakandChakdaraPakistan Department of Physics Faculty of ScienceKing Khalid UniversityP.O.Box 9004AbhaSaudi Arabia Department of Physics Faculty of SciencePort Said UniversityPort SaidEgypt Gomal University Dera Ismail KhanPakistan

Zinc telluride is a versatile wide band gap semiconductor used in many *** it has certain limitations like large dimensions and large band *** alkali metal to its bulk lattice(3D)can reduce its dimensions and lanthanide can produce a red shift in the energy gap by converting it into quaternary *** alkali and lanthanide incorporated quaternary zinc tellurides CsLnZnTe_(3)(Ln=La,Pr,Nd and Sm)form layered crystal structure in which_(∞)^(2)[LnZnTe_(3)]-layers are separated by Cs+*** famous lanthanide contraction is experimental both from lattice constants and bond *** calculated band gaps are 2.26,2.28,2.12,2.05 eV for CsLaZnTe_(3),CsPrZnTe_(3),CsNdZnTe_(3) and CsSmZnTe_(3),*** compounds show direct band gap *** energy band gaps of these compounds have not been evaluated yet both experimentally and *** loss functions,refractive index and dielectric functions were also calculated to explore the potential applications of CsLnZnTe_(3) in optoelectronic devices.

关键词： Chalcogenides Optical materials Electronic structure Dimensions reduction Ab-initio calculations Rare earths

Covalent immobilization and characterization of Rhizopus oryzae lipase on core-shell cobalt ferrite nanoparticles for biodiesel production

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Chinese Journal of Chemical Engineering 2021年第9期34卷 128-136页

作者： Saboura Ashkevarian Jalil Badraghi Fatemeh Mamashli Behdad Delavari ali akbar Saboury Research Institute of Applied Sciences ACECRShahid Beheshti UniversityTehranIran Institute of Biochemistry and Biophysics University of TehranTehranIran Center of Excellence in Biothermodynamics University of TehranTehranIran

Rhizopus oryzae lipase(ROL)was immobilized on the surface of silica coated amino modified CoFe_(2)O_4 nanoparticles and applied for biodiesel *** results indicated more affinity of the ROL toward its substrate upon immobilization,as revealed by a lower Km value for the immobilized ROL compared to its free *** fluorescence spectroscopy indicated a lower intensity for ROL immobilized on CoFe_(2)O_4 ***,immobilized ROL steady state anisotropy measurements presented lower values,which implied assembly of ROL molecules on magnetic nanoparticles upon immobilization as well as their restricted rotation upon covalent *** stability analysis revealed improved activity at higher temperatures for the immobilized enzyme compared to its free ***,Pace analysis to determine protein thermal stability revealed preservation of the protein conformation in the presence of increasing temperatures upon immobilization on ***,ROL immobilized on CoFe_(2)O_(4)nanoparticles exhibited improved efficiency of biodiesel production in agreement with thermal activity ***,the authors suggest application of the lipase molecules immobilized on CoFe_(2)O_(4)nanoparticles for more efficient biodiesel production.

关键词： Lipase immobilization CoFe_(2)O_(4)magnetic nanoparticles Steady state anisotropy Biodiesel Biocatalysis Protein stability

An experimental study on the flexural behavior of heavily steel reinforced beams with high-strength concrete

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Frontiers of Structural and Civil Engineering 2014年第1期8卷 46-56页

作者： Yasser SHARIFI ali akbar MAGHSOUDI Department of Civil Engineering Vali-e-Asr University ofRafsanjan Rafsanjan Iran Department of Civil Engineering Shahid Bahonar University of Kerman Kerman Iran

In recent years, an emerging technology termed high-strength concrete （HSC） has become popular in construction industry. Present study describes an experimental research on the behavior of high-strength concrete beams in ultimate and service state. Six simply supported beams were tested, by applying comprising two symmetric concentrated loads. Tests are reported in this study on the flexural behavior of high-strength reinforced concrete （HSRC） beams made with coarse and fine aggregate together with Microsilica. Test parameter considered includes effect of being compressive reinforcement. Based on the obtained results, the behavior of such members is more deeply reviewed. Also a comparison between theoretical and experimental results is reported here. The beams were made from concrete having compressive strength of 66.81-77.72 N/mm2 and percentage reinforcement ratio （P/Pb） in the range of 0.56% - 1.20%. The ultimate moment for the tested beams was found to be in a good agreement with that of the predicted ultimate moment based on ACI 318-11, ACI 363 and C SA-04 provisions. The predicted deflection based classical formulation based on code provisions for serviceability requirements is found to underestimate the maximum deflection of HSC reinforced beams at service load.

关键词： high-strength concrete (HSC) members flexural behavior reinforced concrete experimental results ultimatemoment

The static and cidal effects of veterinary antibiotics on soil microorganisms in the presence of organic and mineral amendments

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Soil Ecology Letters 2023年第4期5卷 125-135页

作者： ali akbar Safari Sinegani Mehdi Rashtbari Department of Soil Science College of AgricultureBu-Ali Sina UniversityHamadan ***Iran Department of Soil and Plant Microbiome Institute of PhytopathologyChristian-Albrechts-University of KielKielGermany

●Gentamicin initially decreased microbial activity comparative to penicillin higher.●Recovery was comparatively high in oxytetracycline treated soils.●Organic amendments improved the resilience indices.●Unexpectedly the qCO_(2) decreased in the antibiotic treated soils.●The static effects of the applied antibiotics were higher than their cidal *** study aimed to describe the static and cidal adverse effects of antibiotics on soil microbial activity resulting from manure ***,in the present study,the treatments included:without antibiotics;application of gentamicin,oxytetracycline,and penicillin each in different concentrations(50,100,and 200 mg kg−1 dry soil).They were applied in soils treated with and without organic and mineral conditioners(cow manure,biochar,and nano-zeolite).Soil microbial respiration and metabolic quotient were studied at three time periods(1−7,7−30,and 30−90 days)during a 90-day incubation of the treated *** applied to the soil samples significantly decreased soil basal respiration(BR)values compared to those of the control,and the most significant decrease was observed for *** had a short intensive impact,alleviated by manure and biochar,on soil *** a significant initial reduction in substrate-induced respiration(SIR),gentamicin application then caused a substantial increase in SIR *** metabolic quotient decreased in the antibiotic-treated *** study revealed that the static effects of the applied antibiotics in soil were greater than the cidal effects.

关键词： antibiotic resistance metabolic quotient microbial respiration soil resilience

The green fuel from carbon waste： optimization and product selectivity model studies

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International Journal of Coal Science & Technology 2018年第3期5卷 399-410页

作者： Hossein Atashi Fatemeh Rezaeian ali akbar Mirzaei Department of Chemical Engineering University of Sistan and Baluchestan Zahedan Iran Department of Chemistry University of Sistan and Baluchestan Zahedan Iran

Increase in greenhouse gases, has made scientists to substitute alternative fuels for fossil fuels. Nowadays, converting biomass into liquid by Fischer-Tropsch synthesis is a major concern for alternative fuels （gasoline, diesel etc.）. Selectivity of Fischer-Tropsch hydrocarbon product （green fuel） is an important issue. In this study, the experimental data has been obtained from three factors; temperature, H2/CO ratio and pressure in the fixed bed micro reactor. T = 543-618 （K）, P = 3-10 （bar）, H2/CO = 1-2 and space velocity = 4500 （l/h） were the reactor conditions. The results of product modeling for methane （CH4）, ethane （C2H6）, ethylene （C2H4） and CO conversion with experimental data were compared. The effective parameters and the interaction between them were investigated in the model. H2/CO ratio and pressure and interaction between pressure and H2/CO in ethane selectivity model and CO conversion and interaction between temperature and H2/CO ratio in methane selectivity model and ethylene gave the best results. To determine the optimal conditions for light hydrocarbons, ANOVA and RSM were employed. Finally, products optimization was done and results were concluded.

关键词： Selectivity model Fischer-Tropsch synthesis Green fuel Optimization Fixed bed micro reactor Alternative fuels

Dynamic simulation of the effect of time-dependent variation of pH on response variable of the tailing thickener of coal washing plant

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International Journal of Coal Science & Technology 2019年第1期6卷 127-137页

作者： Mehdi Rahimi ali akbar Abdollahzadeh Bahram Rezai Department of Mining and Metallurgical Engineering Amirkabir University of Technology TehranIran Department of Mining Engineering University of KashanKashanIran

Dynamic simulation approach can be used for understanding the nonlinear behavior in mineral processing circuits. In this study, the gel point, the main parameters of batch flux density function and the main parameters of effective solid stress were determined at different conditions (pH, flocculant dosage and particle size). Therefore, the main parameters of phenome no logical model of sedimentation and thickening were determined as a functio n of particle size, pH and flocculant dosages using the result of experimental tests and Curve expert professional software. Then, the dynamic simulation was carried out for the industrial thickener of coal washing plant and the time-dependent variation of response variables was investigated by time-dependent variation of pH of input feed to thickener using the obtained equations. It was observed that it is possible to predict the thickener behavior as a function of time for time dependent variation of pH of input feed to the thickener of coal washing plant using obtained equations that it was not possible using phenomenological model of thickener alone.

关键词： Dynamic simulation Dewatering Ideal continuous thickener Thickener behavior Time-dependent variation of pH

Numerical simulation of incipient particle motion

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International Journal of Sediment Research 2020年第1期35卷 1-14页

作者： ali Nasrollahi ali akbar Salehi Neyshabouri Goodarz Ahmadi Masoud Montazeri Namin Civil Engineering Department Tarbiat Modares University Department of Mechanical and Aeronautical Engineering Clarkson University Civil Engineering Department University of Tehran

A two-dimensional(2 D) computational model for simulation of incipient sediment motion for noncohesive uniform and non-uniform particles on a horizontal bed was developed using the Discrete Element Method(DEM).The model was calibrated and verified using various experimental data reported in the literature and compared with different theories of incipient particle *** analysis was done and the effects of relevant parameters were *** addition to hydrodynamic forces such as drag,shear lift and Magnus force,the particle-particle interaction effects were included in the *** asymptotic critical mobility number was evaluated for various critical particle Reynolds numbers(R*) in the range of very small and very large R*.The obtained curve is classified into four *** was found that in the linear region,the drag force has the principal role on the initiation of ***,the critical mobility number is independent of particle diameter.A procedure for estimating the critical shear velocity directly from the information on particle diameter and roughness height was ***,the mechanism of incipient motion for the different regions was studied and the effect of different forces on the incipient particle motion was *** was found that the maximum effects of lift and Magnus forces were,respectively,less than ten and twenty percent of the total *** drag force,however,was typically the dominant force accounting for majority of the net hydrodynamic force acting on sediment particles at the onset of incipient motion.

关键词： Incipient motion Shields curve Numerical simulation Drag force Lift force Magnus force Discrete Element Method

A novel (G'/G)-expansion method and its application to the Boussinesq equation

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Chinese Physics B 2014年第2期23卷 34-43页

作者： Md.Nur Alam Md.ali akbar Syed Tauseef Mohyud-Din Department of Mathematics Pabna University of Science and Technology Department of Applied Mathematics University of Rajshahi Department of Mathematics HITEC UniversityTaxila Cantt

In this article, a novel （G＇/G）-expansion method is proposed to search for the traveling wave solutions of nonlinear evolution equations. We construct abundant traveling wave solutions involving parameters to the Boussinesq equation by means of the suggested method. The performance of the method is reliable and useful, and gives more general exact solutions than the existing methods. The new （G＇/G）-expansion method provides not only more general forms of solutions but also cuspon, peakon, soliton, and periodic waves.

关键词： (G'/G)-expansion method Boussinesq equation solitary wave solutions auxiliary nonlinear ordinary differential equation