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Spectral features and antibacterial properties of Cu-doped ZnO nanoparticles prepared by sol-gel method

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Chinese Physics B 2016年第7期25卷 459-465页

作者： Alireza Samavati A F Ismail hadi Nur Z Othaman M K Mustafa Centre for Sustainable Nanomaterials Ibnu Sina Institute for Scientific and Industrial ResearchUniversiti Teknologi Malaysia Advanced Membrane Technology Research Centre (AMTEC) Universiti Teknologi Malaysia Faculty of Science Technology and Human Development Universiti Tun Hussein Onn Malaysia

Zn（1-x）Cux O（x=0.00, 0.01, 0.03, and 0.05） nanoparticles are synthesized via the sol-gel technique using gelatin and nitrate precursors. The impact of copper concentration on the structural, optical, and antibacterial properties of these nanoparticles is demonstrated. Powder x-ray diffraction investigations have illustrated the organized Cu doping into ZnO nanoparticles up to Cu concentration of 5%（x = 0.05）. However, the peak corresponding to CuO for x= 0.01 is not distinguishable. The images of field emission scanning electron microscopy demonstrate the existence of a nearly spherical shape with a size in the range of 30–52 nm. Doping Cu creates the Cu–O–Zn on the surface and results in a decrease in the crystallite size. Photoluminescence and absorption spectra display that doping Cu causes an increment in the energy band gap. The antibacterial activities of the nanoparticles are examined against Escherichia coli（Gram negative bacteria）cultures using optical density at 600 nm and a comparison of the size of inhibition zone diameter. It is found that both pure and doped ZnO nanoparticles indicate appropriate antibacterial activity which rises with Cu doping.

关键词： Cu-doped ZnO nanoparticles photoluminescence antibacterial E.coli

An adaptive finite element procedure for crack propagation analysis

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2007年第2期8卷 228-236页

作者： ALSHOAIBI Abdulnaser M. hadi M.S.A. ARIFFIN A.K. Department of Mechanical & Materials Engineering Universiti Kebangsaan Malaysia 43600 Bangi Selangor Darul Ehsan Malaysia

This paper presents the adaptive mesh finite element estimation method for analyzing 2D linear elastic fracture problems. The mesh is generated by the advancing front method and the norm stress error is taken as a posteriori error estimator for the h-type adaptive refinement. The stress intensity factors are estimated by a displacement extrapolation technique. The near crack tip displacements used are obtained from specific nodes of natural six-noded quarter-point elements which are generated around the crack tip defined by the user. The crack growth and its direction are determined by the calculated stress intensity factors. The maximum circumference theory is used for the latter. In evaluating the accuracy of the estimated stress intensity factors, four cases are tested consisting of compact tension specimen, three-point bending specimen, central cracked plate and double edge notched plate. These were carried out and compared to the results from other studies. The crack trajectories of these specimen tests are also illustrated.

关键词： Linear elastic fracture mechanics Adaptive refinement Stress intensity factors Crack propagation

Influence of initial microstructure and grain size on transformation of bainite to austenite in large size forgings

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Journal of Iron and Steel Research International 2018年第5期25卷 554-562页

作者： Emna Ben Fredj hadi Ghasemi Nanesa Mohammad Jahazi Jean-Benoit Morin Department of Mechanical Engineering Ecole deTechnologie Superieure Montreal QC H3C 1K3 Canada Finkl Steel-Sorel St-Joseph-de-Sorel QC J3R 3M8 Canada

The kinetics of austenite formation in the surface and center regions of a 40 t forged ingot of a high-strength medium- carbon low-alloy steel was studied using high-resolution dilatometry. The starting microstructures from the surface or center regions had different proportions of bainite and residual austenite as well as different prior austenite grain sizes. Two heating rates representing the actual heating rates in the surface （5℃ s -1） and center regions （0.5℃ s -1） of large size forged blocks were utilized. Dilatometric curves revealed only one transformation step of austenite formation at both heating rates independent of grain size or proportion of phases. Optical microscopy, field emission gun scanning electron microscopy and X-ray diffraction were used to study microstructure evolution and confirm the results obtained by dilatometry. The kinetic parameters for austenite formation were determined from the dilatometry data by Johnson-Mehl- Avrami-Kolmogorov （JMAK） equation. The JMAK coefficients were determined for each condition of the investigated steels. The calculations indicated that the nucleation and growth of austenite in the surface region were accelerated more than 10,000 times due to a significantly smaller average prior austenite grain size, stability of initial retained austenite, and accumulation of coarse carbides at the surface. The results were discussed in the framework of classical nucleation and growth theories using the kinetic parameters for austenite formation.

关键词： Large size ingot Medium-carbon low-alloy steel Initial microstructure Grain size Austenite formation

Synthesis and Characterization of Nano-sized Zinc Oxide Coating on Cellulosic Fibers： Photoactivity and Flame-retardancy Study

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Chinese Journal of Chemistry 2011年第6期29卷 1239-1245页

作者： Fallah, Moafi hadi Fallah, Shojaie Abdollah Zanianchi, Mohammad Ali Department of Chemistry Faculty of Science University of Guilan P.O. Box 1914 Rasht Iran

We have investigated the effect of zinc oxide as a photocatalyst and durable flame-retardant on cellulosic fibers. Zinc oxide nanocrystals were successfully synthesized and deposited onto cellulosic fibers using sol-gel process at low temperature. The samples were characterized by means of several techniques such as scanning electron microscopy, transmission electron microscopy, diffuse reflectance spectroscopy, X-ray diffraction and thermogra- vimetric analysis. The photocatalytic activity was tested by measuring the photodegradation of methylene blue under UV-Vis illumination. Moreover, flame-retardancy was tested by vertical flame spread test. The optimum add-on value for donating flame-retardancy onto cellulosic fabric was obtained to be in the range of 15.24 to 23.20 g of the ZnO per 100 g of fabric. Thermogravimetric analysis of pure and flame-retarded samples were accomplished and discussed. The results obtained are in agreement with Wall effect theory and Coating theory. The originality of this work on introducing photoactive flame-retarded fibers is highly valuable for industrial implementation.

关键词： cellulosic fiber flame-retardancy photocatalytic self-cleaning zinc oxide coating nanoparticle sol-gel processes

Experimental and Numerical Study of Shear Fracture in Brittle Materials with Interference of Initial Double Cracks

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Acta Mechanica Solida Sinica 2016年第5期29卷 555-566页

作者： hadi Haeri Vahab Sarfarazi Mohammad Fatehi Marji Ahmadreza Hedayat Zheming Zhu Young Researchers and Elite Club Bafgh BranchIslamic Azad UniversityBafghIran Department of Mining Engineering Hamedan University of TechnologytiamedanIran Associate Prof. Head of Mine Exploitation Engineering DepartmentFaculty of Mining and MetallurgyInstitution of EngineeringYazd UniversityYazdIvan Department of Civil and Environmental Engineering Colorado School of MinesGoldenColorado 80401USA College of Architecture and Environment Sichuan UniversityChengdu 610065China

A simultaneous experimental and numerical study of shear fracture of concrete-like materials is carried out using Brazilian disc specimens with initial double edge cracks and fourpoint bending beam specimens with double *** interference effects of two cracks/notches are investigated through varied ligament angles and crack *** is shown that shear fracturing paths change remarkably with the initial ligament angles and crack *** cracked specimens are numerically simulated by an indirect boundary element method.A comparison between the numerical results and the experimental ones shows good agreement.

关键词： cracked Fracture overlapped fracturing ligament simultaneous discontinuity cracking specimen shrinkage

Cracks coalescence mechanism and cracks propagation paths in rock-like specimens containing pre-existing random cracks under compression

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Journal of Central South University 2014年第6期21卷 2404-2414页

作者： hadi Haeri Kourosh Shahriar Mohammad Fatehi Marji Parviz Moarefvand Department of Mining Engineering Science and Research BranchIslamic Azad University Department of Mining and Metallurgical Engineering Amirkabir University of Technology Mine Exploitation Engineering Department Faculty of Mining and MetallurgyInstitution of EngineeringYazd University

The mechanism of cracks propagation and cracks coalescence due to compressive loading of the brittle substances containing pre-existing cracks （flaws） was modeled experimentally using specially made rock-like specimens from Portland Pozzolana Cement （PPC）. The breakage process of the specimens was studied by inserting single and double flaws with different inclination angles at the center and applying uniaxial compressive stress at both ends of the specimen. The first crack was oriented at 50＆#176; from the horizontal direction and kept constant throughout the analysis while the orientation of the second crack was changed. It is experimentally observed that the wing cracks are produced at the first stage of loading and start their propagation toward the direction of uniaxial compressive loading. The secondary cracks may also be produced in form of quasi-coplanar and/or oblique cracks in a stable manner. The secondary cracks may eventually continue their propagation in the direction of maximum principle stress. These experimental works were also simulated numerically by a modified higher order displacement discontinuity method and the cracks propagation and cracks coalescence were studied based on Mode I and Mode II stress intensity factors （SIFs）. It is concluded that the wing cracks initiation stresses for the specimens change from 11.3 to 14.1 MPain the case of numerical simulations and from 7.3 to 13.8 MPa in the case of experimental works. It is observed that cracks coalescence stresses change from 21.8 to 25.3 MPa and from 19.5 to 21.8 MPa in the numerical and experimental analyses, respectively. Comparing some of the numerical and experimental results with those recently cited in the literature validates the results obtained by the proposed study. Finally, a numerical simulation was accomplished to study the effect of confining pressure on the crack propagation process, showing that the SIFs increase and the crack initiation angles change in this case.

关键词： crack propagation crack coalescence rock-like specimen numerical simulation experiment

Investigating the potential of using acoustic frequency on the degradation of linear alkylbenzen sulfonates from aqueous solution

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2007年第9期8卷 1462-1468页

作者： DEHGHANI Mohammad hadi MAHVI Amir Hossein NAJAFPOOR Ali Asghar AZAM Kamal Department of Environmental Health Engineering School of Public HealthCenter for Environmental ResearchMedical Sciences/University of TehranTehranI.R. Iran Department of Environmental Health School of Public HealthMashhad University of Medical SciencesMashhadI.R. Iran Department of Epidemiology and Biostatistics School of Public HealthMedical Sciences/University of TehranTehranI.R. Iran

The effectiveness of using acoustical （sonochemical） reactor for degradation of linear alkylbenzen sulfonate （LAS） from aqueous solution was investigated. LASs are anionic surfactants, found in relatively high amounts in domestic and industrial wastewaters. In this study, experiments on LAS solution were performed using methylene blue active substances （MBAS） method. The effectiveness of acoustical processor reactor for LAS degradation is evaluated with emphasis on the effect of treatment time and initial LAS concentration. Experiments were performed at initial concentrations of 0.2, 0.5, 0.8 and 1.0 mg/L, acoustic frequency of 130 kHz, applied power of 500 W and temperature of 18℃-20℃. At the conditions involved, LAS degradation was found to increase with increasing sonochemical time. In addition, as the concentration increased, the LAS degradation rate decreased in the acoustical processor reactor.

关键词： Acoustical reactor Linear alkylbenzen sulfonate (LAS) Acoustic frequency Treatment time Power

Process development for green part printing using binder jetting additive manufacturing

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Frontiers of Mechanical Engineering 2018年第4期13卷 504-512页

作者： hadi MIYANAJI Morgan ORTH Junaid Muhammad AKBAR Li YANG Department of Industrial Engineering University of Louisville Louisville KY 40292 USA Department of Mechanical Engineering University of LouisvilleLouisville KY 40292 USA

Originally developed decades ago, the binder jetting additive manufacturing （B J-AM） process possesses various advantages compared to other additive manufacturing （AM） technologies such as broad material compat- ibility and technological expandability. However, the adoption of B J-AM has been limited by the lack of knowledge with the fundamental understanding of the process principles and characteristics, as well as the relatively few systematic design guideline that are available. In this work, the process design considerations for B J-AM in green part fabrication were discussed in detail in order to provide a comprehensive perspective of the design for additive manufacturing for the process. Various process factors, including binder saturation, in- process drying, powder spreading, powder feedstock characteristics, binder characteristics and post-process curing, could significantly affect the printing quality of the green parts such as geometrical accuracy and part integrity. For powder feedstock with low flowability, even though process parameters could be optimized to partially offset the printing feasibility issue, the qualities of the green parts will be intrinsically limited due to the existence of large internal voids that are inaccessible to the binder. In addition, during the process development, the balanced combination between the saturation level and in-process drying is of critical importance in the quality control of the green parts.

关键词： binder jetting additive manufacturing green part process optimization process development

A basal area increment model for individual trees in mixed continuous cover forests in Iranian Caspian forests

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Journal of Forestry Research 2020年第1期31卷 99-106页

作者： Nishtman Hatami Peter Lohmander Mohammad hadi Moayeri Soleiman Mohammadi Limaei Department of Forestry Faculty of Natural ResourcesGorgan University of Agricultural Sciences and Natural ResourcesP.O.Box 386mGorganIran Optimal Solutions in Cooperation with Linnaeus University Va¨xjo¨Sweden Department of Forestry Faculty of Natural ResourcesUniversity of GuilanP.O.Box 1144Sowmeh SaraIran

The aim of this study was to develop and test a new basal area growth model in mixed species continuous cover forests in northern *** 421 core samples from 6 main species in the forest area to develop our growth *** each plot,we measured variables such as total tree height(m),diameter at breast height(DBH)(cm)and basal area of larger trees as cumulative basal areas of trees(GCUM)ofDBH[5 *** empirical data were analyzed using regression *** was a statistically significant nonlinear function between the annual basal area increment,as the dependent variable,and the basal area of the individual trees and competition as explanatory *** area from the largest trees,was circular plot with area of 0.1 *** was estimated for trees of DBH>5 ***,we investigated the dependencies of diameter growth of different species on stand density at different levels of competition,and diameter development of individual trees through *** results indicate that competition caused by larger neighborhood trees has a negative effect on *** addition,the maximum diameter increment is affected by competition ***,the maximum diameter increment of species occurs when the trees are about 35–40 cm in dense-forest(40 to 0 m^2 per ha)and when the trees are about 60 to 70 cm in very dense forest(60 to 0 m^2 per ha)which is more likely to Caspian natural forests with high level density due to uneven-aged composition of stands.

关键词： Individual-tree model Iranian Caspian forests Continuous cover forestry Mixed stands Uneven-aged management