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Defence Technology（防务技术） 2019年第2期15卷 193-197页

作者： Saeid Bagherpour Mohammad Mahdavi ebrahim abedini Department of Chemistry Malek-ashtar University of Technology

Miniature flares containing magnesium/sodium nitrate compounded with different binders were studied for increasing luminosity and luminous efficiency in various fuel oxidizer ratio and flare *** polyester, Bisphenol-A epoxy resin, calcium resinate, and nitrocellulose were used as binders for construction the flares. Experimental results showed that luminous efficiency was higher for polyester based flares. Due to the difference in decomposition progress of various binders and the exothermic reaction between binder and oxidizer the luminous efficiency of the mixtures were 31000,28900, 27800 and 25100 cd respectively for polyester, epoxy, calcium resinate, and nitrocellulose. It was found that nitrocellulose as an energetic binder produces the highest light intensity in comparison to other binders, but the burning rate is higher and the burning time is lower than the other *** analysis of four binders showed that the heat of reactions was directly related to the amount of light output and luminosity.

关键词： Miniature flare Illuminating compositions Luminous efficiency Binder

An investigation of an Emden-Fowler equation from thin film flow

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Acta Mechanica Sinica 2012年第2期28卷 300-307页

作者： ebrahim Momoniat Centre for Differential Equations Continuum Mechanics and ApplicationsSchool of Computational and Applied MathematicsUniversity of the WitwatersrandJohannesburgPrivate Bag 3Wits 2050South Africa

A third-order ordinary differential equation （ODE） for thin film flow with both Neumann and Dirichlet bound- ary conditions is transformed into a second-order nonlinear ODE with Dirichlet boundary conditions. Numerical solu- tions of the nonlinear second-order ODE are investigated us- ing finite difference schemes. A finite difference formulation to an Emden-Fowler representation of the second-order non- linear ODE is shown to converge faster than a finite differ- ence formulation of the standard form of the second-order nonlinear ODE. Both finite difference schemes satisfy the von Neumann stability criteria. When mapping the numeri- cal solution of the second-order ODE back to the variables of the original third-order ODE we recover the position of the contact line. A nonlinear relationship between the position of the contact line and physical parameters is obtained.

关键词： Thin film Third-order ODE Emden-Fowler equation Finite differences Contact angle

A comparison of two formulations of the fin efficiency for straight fins

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Acta Mechanica Sinica 2012年第2期28卷 444-449页

A formulation of the fin efficiency based on New- ton＇s law of cooling is compared with a formulation based on a ratio of heat transferred from the fin surface to the sur- rounding fluid to the heat conducted through the base. The first formulation requires that the solution of the nonlinear fin equations for constant heat transfer coefficient and constant thermal conductivity is known, whilst the second formulation of the fin efficiency requires only that a first integral of the model equation is known. This paper shows the first for- mulation of the fin efficiency contains approximation errors as only power series and approximate solutions to the non- linear fin equations have been determined. The second for- mulation of the fin efficiency is exact when the first integrals can be determined.

关键词： Fin equation First integral Fin efficiency

MXene‑Graphene Composites:A Perspective on Biomedical Potentials

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Nano-Micro Letters 2022年第8期14卷 112-123页

作者： ebrahim Mostafavi Siavash Iravani Stanford Cardiovascular Institute Stanford University School of MedicineStanfordCA 94305USA Department of Medicine Stanford University School of MedicineStanfordCA 94305USA Faculty of Pharmacy and Pharmaceutical Sciences Isfahan University of Medical SciencesIsfahanIran

MXenes,transition metal carbides and nitrides with graphene-like structures,have received considerable attention since their first *** the other hand,Graphene has been extensively used in biomedical and medicinal *** and graphene,both as promising candidates of two-dimensional materials,have shown to possess high potential in future biomedical applications due to their unique physicochemical properties such as superior electrical conductivity,high biocompatibility,large surface area,optical and magnetic features,and extraordinary thermal and mechanical *** special structural,functional,and biological characteristics suggest that the hybrid/composite structure of MXene and graphene would be able to meet many unmet needs in different fields;particularly in medicine and biomedical engineering,where high-performance mechanical,electrical,thermal,magnetic,and optical requirements are ***,the hybridization and surface functionalization should be further explored to obtain biocompatible composites/platforms with unique physicochemical properties,high stability,and *** addition,toxicological and long-term biosafety assessments and clinical translation evaluations should be given high priority in *** very limited studies have revealed the excellent potentials of MXene/graphene in biomedicine,the next steps should be toward the extensive research and detailed analysis in optimizing the properties and improving their functionality with a clinical and industrial ***,different synthesis/fabrication methods and performances of MXene/graphene composites are discussed for potential biomedical *** potential toxicological effects of these composites on human cells and tissues are also covered,and future perspectives toward more successful translational applications are *** current state-of-the-art biotechnological advances in the use of MXene-Graphene composites,as wel

关键词： Graphene MXene Composites Hybrid structures Biocompatibility Cancer theranostics Biomedical engineering

Analysis of element loss, densification, and defects in laser-based powder-bed fusion of magnesium alloy WE43

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Journal of Magnesium and Alloys 2022年第8期10卷 2118-2136页

作者： Faridreza Attarzadeh ebrahim Asadi Department of Mechanical Engineering The University of MemphisMemphisTN 38152United States

It is well known that laser-based powder-bed fusion(L-PBF) additive manufacturing of magnesium(Mg) and its alloys is associated with high Mg loss due to vaporization(MgLoss) and high incidence of many types of defects in the manufactured parts/samples. Despite this,MgLoss, densification, and defect characteristics have not been holistically considered in the determination of the optimal values of L-PBF processing parameters for Mg and its alloys. This study presents a combined modeling and experimental approach applied for a widely used Mg alloy(WE43) to address this shortcoming in the literature. First, an experimentally calibrated model is proposed to determine MgLoss as a function of the L-PBF processing parameters. The model couples the temperature profile using a double ellipsoidal heat source with a Langmuir vaporization model and is calibrated using the width of the single-track L-PBF process and the measured Mglossusing inductively coupled plasma mass spectrometry(ICP-MS). Second, the densification of the samples is determined using a modification of the Archimedes method that considers the amount of MgLossin the calculation of the relative density. Third, a comprehensive and quantitative study is conducted on the relationships between the characteristics of porosity defects and the L-PBF processing parameters. Finally, the optimized L-PBF processing parameters are determined by considering the MgLoss, densification, and the characteristics of defects. The present study yields 0.23 wt.% MgLosscompared to 2 wt.% MgLossthat was reported in the previous studies. Furthermore, more than 99.5% densification is achieved while only ~2% and ~0.5% of the total defects are characterized as keyhole and lack of fusion defects, respectively.

关键词： WE43 magnesium alloy Additive manufacturing Powder-bed fusion Mg loss Vaporization Defects

A closed form of a kurtosis parameter of a hypergeometric-Gaussian type-Ⅱ beam

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Chinese Physics B 2016年第4期25卷 154-160页

作者： Khannous F ebrahim A A A Belafhal A adida Morocco

Based on the irradiance moment definition and the analytical expression of waveform propagation for hypergeometric- Gaussian type-II beams passing through an ABCD system, the kurtosis parameter is derived analytically and illustrated numerically. The kurtosis parameters of the Gaussian beam, modified Bessel modulated Gaussian beam with quadrature radial and elegant Laguerre-Gaussian beams are obtained by treating them as special cases of the present treatment. The obtained results show that the kurtosis parameter depends on the change of the beam order m and the hollowness parameter p, such as its decrease with increasing m and increase with increasing p.

关键词： Kurtosis parameter hypergeometric-Gaussian type-II beams paraxial optical ABCD system

Multi-objective optimal design of braced frames using hybrid genetic and ant colony optimization

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Frontiers of Structural and Civil Engineering 2016年第4期10卷 472-480页

作者： Mehdi BABAEI ebrahim SANAEI Department of Civil Engineering Faculty of Engineering University of Zanjan Zanjan 45371-38791 Iran

In this article, multi-objective optimization of braced frames is investigated using a novel hybrid algorithm. Initially, the applied evolutionary algorithms, ant colony optimization （ACO） and genetic algorithm （GA） are reviewed, followed by developing the hybrid method. A dynamic hybridization of GA and ACO is proposed as a novel hybrid method which does not appear in the literature for optimal design of steel braced frames. Not only the cross section of the beams, columns and braces are considered to be the design variables, but also the topologies of the braces are taken into account as additional design variables. The hybrid algorithm explores the whole design space for optimum solutions. Weight and maximum displacement of the structure are employed as the objective functions for multi-objective optimal design. Subsequently, using the weighted sum method （WSM）, the two objective problem are converted to a single objective optimization problem and the proposed hybrid genetic ant colony algorithm （HGAC） is developed for optimal design. Assuming different combination for weight coefficients, a trade-offbetween the two objectives are obtained in the numerical example section. To make the final decision easier for designers, related constraint is applied to obtain practical topologies. The achieved results show the capability of HGAC to find optimal topologies and sections for the elements.

关键词： multi-objective hybrid algorithm ant colony genetic algorithm displacement weighted sum method steelbraced frames

Geology,geochemistry,fluid inclusions and O-H stable isotope constraints on genesis of the Lake Siah Fe-oxide±apatite deposit,NE Bafq,Central Iran

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Acta Geochimica 2020年第6期39卷 920-946页

作者： ebrahim TaleFazel Mahin Rostami Department of Geology Faculty of Science.Bu-Ali Sina UniversityHamedanIran

The Lake Siah iron±apatite deposit is situated in the Bafq Mining District(BMD),Central *** iron±apatite orebodies are hosted by a succession of rhyolite,rhyolitie tuff,trachyandesite,and andesite of Lower Cambrian *** host rock has undergone wide-spread alteration and mineralization stages including Na(albite-quartz),followed by Na-Ca(albite-calcite--am-phibole-magnetite±quartz±epidote),magnetite-ap-atite,K(biotite±K-feldspar),hydrolytic(sericite-quartz),and argillic(kaolinite--montmorillonite±dickite),*** microprobe analyses(EPMA)from mag-netite and hematite show significant variations of trace *** on Ni/Cr+Mn and Ca+Al+Mn ver-sus Ti+V diagrams,the majority of magnetite samples belong to Kiruna-type *** least,three generations of fluid inclusions,including solid-bearing(L+V+S)(Type I),liquid-rich(L+V)(Type II-A),vapor-rich(L+V)(Type II-B),and liquid or vapor mono-phase(Type II),are recognized in quartz and *** solid-bearing fluid inclusions in quartz completely homogenized at temperatures of 150 to>530℃with salinities of 30--58 wt%NaCl ***-rich fluid inclusions in apatite homogenized to a liquid phase at 175--210℃,whereas the vapor-rich fuid inclusions homogenized to a vapor at 335-350°*** isotope analysis was carried out on quartz and *** hydrogen and oxygen isotopic compositions of quartz(8"Onuid values of 7.57-11.04%)show that with progress in time the ore-forming solutions gradually evolved from a magmatic to meteoric-dominated source.

关键词： Iron oxide-apatite Lower Cambrian Kirunatype Bafq Mining District Lake Siah

Influence of electron correlations on double-capture process in proton helium collisions

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Chinese Physics B 2015年第7期24卷 219-225页

作者： Hoda Ghavaminia ebrahim Ghanbari-Adivi Department of Physics Faculty of SciencesUniversity of Isfahan

The first-order correct-boundary Coulomb–Born distorted-wave approximation is used to study the double-electron capture by protons from the ground-state helium atoms at intermediate and high impact energies. The differential double capture cross sections are obtained as a function of the projectile scattering angle and the total cross sections as a function of the impact energy. In the considered range of impact energy, our calculation shows that although the results are not so sensitive to the static inter-electronic correlations in the initial channel, the strong final-state correlations have a large effect on the magnitudes of the double capture cross sections. The calculated differential and integral cross sections are compared with their available experimental values. The comparison shows a good agreement between the present calculations and the measurements. The comparison of the integral cross sections shows that the present approach is compatible with other theories.

关键词： Coulomb–Born approximation double-electron capture Coulomb boundary conditions differen-tial and total cross sections

Effect of steel slag aggregate and bitumen emulsion types on the performance of microsurfacing mixture

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Journal of Traffic and Transportation Engineering(English Edition) 2020年第2期7卷 215-226页

作者： Mahdi Zalnezhad ebrahim Hesami Highways and Transportation Engineering Babol Noshirvani University of TechnologyBabolIran AF Infrastructure AB StockholmSweden

Microsurfacing has recently been accepted widely as an effective method for preventive maintenance of *** is a mixture of cationic polymer-modified bitumen emulsion,100%manufactured well-graded fine aggregate,mineral filler,water,and chemical *** this research,in order to evaluate the performance of steel slag in microsurfacing mixture,two types of bitumen emulsions(cationic quick setting and cationic slow setting)were used together with three types of mixtures in which 100%siliceous aggregate was used as a control mixture and then steel slag was replaced by 61%and 100%aggregate of control *** performance of the samples was evaluated by experiments included wet cohesion test,wet track abrasion test,and loaded wheel test,according to international slurry surfacing association(ISSA)A143 guideline and ASTM D6372 *** results of tests showed that steel slag aggregate has proper compatibility with both of bitumen emulsion types judged by its desirable physical,chemical,and mechanical *** alkali characteristic of the steel slag leads to a stronger adhesion of these materials to acidic bitumen and cause prevented the stripping in the vicinity of water in comparison to the control ***,steel slag-containing mixtures displayed a more appropriate behavior in terms of rutting and stripping distresses.

关键词： Microsurfacing Steel slag aggregate Abrasion resistance Aggregate and bitumen adhesion