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Fabrication of NiFe layered double hydroxide with well-defined laminar superstructure as highly efficient oxygen evolution electrocatalysts

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Nano Research 2019年第6期12卷 1327-1331页

作者： Hao Zhang Haoyi Li Bilal akram Xun Wang Department of Chemistry Tsinghua UniversityBeijing 100084China

Structure-activity relationship (SAR) is the key problem of nanoscience,thus to fabricate novel and well-defined nanostructure will provide a new insight on catalyst preparation *** active and low cost electrocatalysts for oxygen evolution reaction (OER) are of great importance for future renewable energy conversion and ***,NiFe-based layered double hydroxides with laminar structure (NFLS) were successfully fabricated via a one-step hydrothermal approach by using sodium dodecyl sulfate as *** as-fabricated NFLS showed a well-defined periodic layered-stacking geometry with a scale down to *** from the unique structure,NFLS exhibited an excellent catalytic activity towards OER with current densities of 10 mA·cm^-2 at overpotential of 197 *** synergistic effect of Ni and Fe plays a key role in electrode *** present work provides a new insight to improve the OER performance by rational design of electrocatalysts with unique structures.

关键词： layered double hydroxide structure-activity relationship ultrathin nanostructure electrocatalysis oxygen evolution reaction

Effect of buried plates on scour profiles downstream of hydraulic jump in open channels with horizontal and reverse bed slopes

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Water Science and Engineering 2016年第4期9卷 329-335页

作者： akram Abbaspour Sahar Parvini Ali Hosseinzadeh Dalir Department of Water Engineering University of Tabriz

Local scour downstream of sluice gates in erosive beds is one of the main concerns of hydraulic engineers because it can cause considerable damage to *** researchers have conducted various studies to predict the maximum depth and length of scour holes and to develop new methods to control this *** the methods that have recently been examined,embedded buried plates are used to control the scour in the erosive *** this study,using a physical model,the effect of buried plates in erosive beds on the depth of scour downstream of a hydraulic jump was *** experiments were performed in which plates were buried at 50° and 90° angles at different distances from the apron in open channels with horizontal and reverse bed *** results of experiments in which the scour profiles were drawn in dimensionless forms show that the angle and position of the plates are important to controlling and reducing scour *** fact,by reducing the angle of buried plates,the maximum depth of scour is also ***,comparison of the results of a single buried plate and double buried plates shows that using two buried plates at the distances of 30 and 45 cm from the non-erodible bed is more effective in reducing the scour *** best distances of the buried plates with angles of 90° and 50° from the non-erodible bed are 45 cm and 30 cm,respectively,in the condition with a single buried plate.

关键词： Local scour Buried plates Hydraulic jump Horizontal and reverse bed slopes

Evaluating location specific strain rates, temperatures,and accumulated strains in friction welds through microstructure modeling

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Defence Technology（防务技术） 2018年第2期14卷 83-92页

作者： Javed akram Prasad Rao Kalvala Vikas Jindal Mano Misra Dept. of Metallurgical Engineering University of Utah Dept. of Metallurgical Engineering Indian Institute of Technology(BHU)

A microstructural simulation method is adopted to predict the location specific strain rates, temperatures, grain evolution, and accumulated strains in the Inconel 718 friction welds. Cellular automata based 2D microstructure model was developed for Inconel 718 alloy using theoretical aspects of dynamic recrystallization. Flow curves were simulated and compared with experimental results using hot deformation parameter obtained from literature work. Using validated model, simulations were performed for friction welds of Inconel 718 alloy generated at three rotational speed i.e., 1200, 1500, and1500 RPM. Results showed the increase in strain rates with increasing rotational speed. These simulated strain rates were found to match with the analytical results. Temperature difference of 150 K was noticed from center to edge of the weld. At all the rotational speeds, the temperature was identical implying steady state temperature(0.89 T_m) attainment.

关键词： Microstructure modeling Dynamic recrystallization Friction welding Inconel 718 EBSD Hot deformation Strain map

Traversable wormhole solutions in the f(R)theories of gravity under the Karmarkar condition

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Chinese Physics C 2022年第9期46卷 276-286页

作者： Adnan Malik Fatemah Mofarreh Aqsa Zia akram Ali Department of Mathematics University of Management and TechnologySialkot CampusPakistan Mathematical Science Department Faculty of Science Princess Nourah bint Abdulrahman University.Riyadh 11546 Saudi Arabia Department of Mathematics College of ScienceKing Khalid University9004 AbhaSaudi Arabia

This paper examines traversable wormhole models in the f(R) theories of gravity by applying the Karmarkar condition. For this purpose, we consider spherically symmetric space-time to examine the structure of wormholes. First, we investigate wormholes and their geometry using the redshift function under various conditions. Subsequently, we discuss the embedding diagram of the upper and lower universe using radial coordinates in two and three-dimensional Euclidean affine space. Three exclusive models are considered for the f(R) theories of gravity,and the radial and tangential pressures are observed. Furthermore, by taking a definite shape function, we observe the behavior of energy conditions. We determine that energy conditions are violated, and their violation is generic and represents the presence of exotic matter. According to Einstein’s field theory, the existence of wormholes is predicated on the occurrence of rare material. Hence, we conclude that our study is more realistic and stable.

关键词： wormhole geometry Karmarkar condition red shift function energy conditions

Comparative characterization of iridium loading on catalyst assessment under different conditions

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International Journal of Minerals,Metallurgy and Materials 2021年第7期28卷 1233-1239页

作者： Zahra Amirsardari akram Dourani Mohamad Ali Amirifar Nooredin Ghadiri Massoom Space Transportation Research Institute Iranian Space Research CenterTehranIran

To discuss the potential role of iridium(Ir)nanoparticles loaded under atmospheric and high pressures,we prepared a series of cata-lysts with the same active phase but different contents of 10wt%,20wt%,and 30wt%on gamma-alumina for decomposition of ***-der atmospheric pressure,the performance of the catalyst was better when 30wt%of the Ir nanoparticles was used with chelating agent that had greater selectivity of approximately 27%.The increase in the reaction rate from 175 to 220 h^(−1)at higher Ir loading(30wt%)was due to a good dispersion of high-number active phases rather than an agglomeration *** a satisfactory result of this investigation at high pressure,Ir catalysts with different weight percentages showed the same stability against crushing and activity with a characteristic velocity of approxim-ately 1300 m/s.

关键词： iridium nanoparticles catalyst activity laboratory reactor atmospheric pressure high pressure

Optimization of energy consumption and environmental impacts of chickpea production using data envelopment analysis(DEA)and multi objective genetic algorithm(MOGA)approaches

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Information Processing in Agriculture 2016年第3期3卷 190-205页

作者： Behzad Elhami Asadollah akram Majid Khanali Department of Agricultural Machinery Engineering Faculty of Agricultural Engineering and TechnologyUniversity of TehranKarajIran

Energy consumption in agricultural products and its environmental damages has increased in recent *** cycle assessment(LCA)has been introduced as a suitable tool for evaluation environmental impacts related to a product over its life *** this study,optimization of energy consumption and environmental impacts of chickpea production was conducted using data envelopment analysis(DEA)and multi objective genetic algorithm(MOGA)*** were collected from 110 chickpea production enterprises using a face to face questionnaire in the cropping season of *** results of optimization revealed that,when applying MOGA,optimum energy requirement for chickpea production was significantly lower compared to application of DEA technique;so that,total energy requirement in optimum situation was found to be 31511.72 and 27570.61 MJ ha^-1 by using DEA and MOGA techniques,respectively;showing a reduction by 5.11%and 17%relative to current situation of energy *** of environmental impacts by application of MOGA resulted in reduction of acidification potential(ACP),eutrophication potential(EUP),global warming potential(GWP),human toxicity potential(HTP)and terrestrial ecotoxicity potential(TEP)by 29%,23%,10%,6%and 36%,*** capable of reducing the energy consumption from machinery,farmyard manure(FYM)diesel fuel and nitrogen fertilizer(the mostly contributed inputs to the environmental emissions)by 59%,28.5%,24.58%and 11.24%,***,the MOGA technique showed a superior performance relative to DEA approach for optimizing energy inputs and reducing environmental impacts of chickpea production system.

关键词： Data envelopment analysis Energy Life cycle assessment Multi objective genetic algorithm

Combined application of Artificial Neural Networks and life cycle assessment in lentil farming in Iran

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Information Processing in Agriculture 2017年第1期4卷 18-32页

作者： Behzad Elhami Majid Khanali Asadollah akram Department of Agricultural Machinery Engineering Faculty of Agricultural Engineering and TechnologyCollege of Agriculture and Natural ResourcesUniversity of TehranKarajIran

In this study,an Artificial Neural Network(ANN)was applied to model yield and environmental emissions from lentil cultivation in Esfahan province of *** was gathered from lentil farmers using face to face questionnaire method during 2014–2015 cropping *** cycle assessment(LCA)was applied to investigate the environmental impact categories associated with lentil *** on the results,total energy input,energy output to input ratio and energy productivity were determined to be 32,970.10 MJ ha1,0.902 and 0.06 kg MJ1,*** greatest amount of energy consumption was attributed to chemical fertilizer(42.76%).Environmental analysis indicated that the acidification potential was higher than other environmental impact categories in lentil production *** results showed that the production of agricultural machinery was the main hotspot in abiotic depletion,eutrophication,global warming,human toxicity,fresh water aquatic ecotoxicity,marine aquatic ecotoxicity and terrestrial ecotoxicity impact categories,while direct emissions associated with lentil cultivation was the main hotspot in acidification potential and photochemical oxidation *** addition,diesel fuel was the main hotspot only in ozone layer *** ANN model with 9-10-6-11 structure was identified as the most appropriate network for predicting yield and related environmental impact categories of lentil ***,the results of sensitivity analysis revealed that farmyard manure had the greatest effect on the most of the environmental impacts,while machinery was the most affecting parameter on the yield of the crop.

关键词： Artificial Neural Network Energy balance Environmental impacts Lentil production Sensitivity analysis

The effect of pulse voltage rise rate on the polypropylene surface hydrophilic modification by ns pulsed nitrogen DBD

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Plasma Science and Technology 2023年第10期25卷 6-14页

作者：刘峰李舒豪赵昱雷 Shakeel akram 张丽方志 College of Electrical Engineering and Control Science Nanjing Tech UniversityNanjing 211816People's Republic of China

The nanosecond(ns) pulsed nitrogen dielectric barrier discharge(DBD) is employed to enhance the hydrophilicity of polypropylene(PP) surface and improve its application *** discharge characteristics of the ns pulsed nitrogen DBD with different pulse rise times(from 50to 500 ns) are investigated by electrical and optical diagnostic methods and the discharge uniformity is quantitatively analyzed by image processing *** characterize the surface hydrophilicity,the water contact angle(WCA) is measured,and the physical morphology and chemical composition of PP before and after modification are analyzed to explore the effect of plasma on PP *** is found that with increasing pulse rise time from 50 to 500 ns,DBD uniformity becomes worse,energy efficiency decreases from 20% to 10.8%,and electron density decrease from 6.6 × 10^(11)to 5.5 × 10^(11)cm^(-3).The tendency of electron temperature is characterized with the intensity ratio of N_(2)/N_(2)^(+)emission spectrum,which decreases from 17.4 to15.9 indicating the decreasing of T_(e) with increasing pulse rise time from 50 to 500 *** PP surface treated with 50 ns pulse rise time DBD has a lower WCA(~47°),while the WCA of PP treated with 100 to 500 ns pulse rise time DBD expands gradually(~50°–57°).According to the study of the fixed-point WCA values,the DBD-treated PP surface has superior uniformity under50 ns pulse rise time(3° variation) than under 300 ns pulse rise time(8° variation).After DBD treatment,the increased surface roughness from 2.0 to 9.8 nm and hydrophilic oxygencontaining groups on the surface,***(-OH) and carbonyl(C=O) have played the significant role to improve the sample’s surface *** short pulse voltage rise time enhances the reduced electric field strength(E/n) in the discharge space and improves the discharge uniformity,which makes relatively sufficient physical and chemical reactions have taken place on the PP surface,resulting in better treatment uniformit

关键词： dielectric barrier discharge pulse rise time material surface modification polypropylene uniformity

Two-dimensional investigation of characteristic parameters and their gradients for the self-generated electric and magnetic fields of laser-induced zirconium plasma

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Plasma Science and Technology 2024年第5期26卷 138-155页

作者： Tayyaba SAJID Shazia BASHIR Mahreen akram Maira RAZZAQ Khaliq MAHMOOD Centre for Advanced Studies in Physics Institute of PhysicsGovernment College University LahoreLahore 54000Pakistan Department of Physics Institute of PhysicsGovernment College University LahoreLahore 54000Pakistan

Two-dimensional diagnosis of laser-induced zirconium(Zr)plasma has been experimentally performed using the time-of-flight method by employing Faraday cups in addition to electric and magnetic *** characteristic parameters of laser-induced Zr plasma have been evaluated as a function of different laser irradiances ranging from 4.5 to 11.7 GW cm-2 at different axial positions of 1–4 cm with a fixed radial distance of 2 cm.A well-supporting correlation between the plume parameters and the laser-plasma-produced spontaneous electric and magnetic(E and B)fields was *** measurements of the characteristic parameters and spontaneously induced fields were observed to have an increasing trend with the increasing laser ***,when increasing the spatial distance in both the axial and radial directions,the plasma parameters(electron/ion number density,temperature and kinetic energy)did not show either continuously increasing or decreasing trends due to various kinetic and dynamic processes during the spatial evolution of the ***,the E and B fields were observed to be always diffusing away from the *** radial component of electron number densities remained higher than the axial number density component,whereas the axial ion number density at all laser irradiances and axial distances remained higher than the radial ion number *** higher axial self-generated electric field(SGEF)values than radial SGEF values are correlated with the effective charge-separation mechanism of electrons and *** generation of a self-generated magnetic field is observed dominantly in the radial direction at increasing laser irradiance as compared to the axial one due to the deflection of fast-moving electrons and the persistence of two-electron temperature on the radial axis.

关键词： Faraday cup axial and radial expansion space-charge effect laser-induced zirconium plasma two-electron temperature distribution self-generated electric and magnetic fields