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An insight into the mechanical behavior of binary granular soils

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Particuology 2015年第4期13卷 82-89页

作者： F.Vahidi-nia A.Lashkari s.M.Binesh Department of civil and Environmental Engineering Shiraz University of Technology

This paper investigates the participation of the fines fraction in the load-carrying structure of binary mixtures of granular soils. For this purpose, various fractions of two fine sands were added to two coarse sands with the same particle size distribution, but different particle shape characteristics. Based on the results of 144 direct shear tests, it was found that fines participation in the load-bearing structure increases with fines content. At the same fines content, the participation of the fines in the load-carrying structure of loose mixtures is greater than in samples that were initially compacted. In addition, it was observed that fines participation rises with the increase in the average size of the fines fraction.

关键词： sand Particle size ratio Fines content Fines participation factor lntergranular void ratio

serological surveillance for sARs-coV-2 antibodies among students,faculty and staff within a large university system during the pandemic

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World Journal of Virology 2025年第1期14卷 99-107页

作者： Marcos G Pinheiro Gabriela G O Alves Maria Eduarda R conde sofia L costa Regina c s sant’Anna Isa M F Antunes Mônica c carneiro Fabio s Ronzei Julia c scaffo Felipe R Pinheiro Lialyz s Andre helvecio c Povoa Valéria T Baltar Fabíola Giordani Eduarda s hemerly Gisele c Alexandre Karla c de Paula Márcio Watanabe Antonio claudio L da Nóbrega Jackeline christiane P Lobato Fabio Aguiar-Alves Laboratory of Molecular Epidemiology and Biotechnology Rodolpho Albino University LaboratoryFluminense Federal UniversityNiterói 24241000Rio de JaneiroBrazil Estácio de sáUniversity Nova Friburgo 28611135Rio de JaneiroBrazil Pathology Program Medicine schoolFluminense Federal UniversityNiterói 24070090Rio de JaneiroBrazil Department of Pharmaceutical sciences Lloyd L.Gregory School of PharmacyPalm Beach Atlantic UniversityWest Palm BeachFL 33401United States health Institute of Nova Friburgo Fluminense Federal UniversityNova Friburgo 28613001Rio de JaneiroBrazil Department of Epidemiology and Biostatistics Institute of Collective Health(ISC)Fluminense Federal UniversityNiterói 24033900Rio de JaneiroBrazil Institute of Physical Education Fluminense Federal UniversityNiterói 24020005Rio de JaneiroBrazil Department of statistics Fluminense Federal UniversityNiterói 24210200Rio de JaneiroBrazil Department of Physiology and Pharmacology Fluminense Federal UniversityNiterói 24210130Rio de JaneiroBrazil

BAcKGROUND At the end of December 2019,the world faced severe acute respiratory syndrome-coronavirus 2(sARs-coV-2),which led to the outbreak of coronavirus disease 2019(cOVID-19),associated with respiratory *** virus has shown significant challenges,especially for senior citizens,patients with other underlying illnesses,or those with a sedentary *** tests conducted early on have helped identify how the virus is transmitted and how to curb its *** study hypothesis was that the rapid serological test for sARs-coV-2 antibodies could indicate the immunoreactive profile during the cOVID-19 pandemic in a university *** To conduct active surveillance for serological expression of anti-sARs-coV-2 antibodies in individuals within a university setting during the cOVID-19 *** This sectional study by convenience sampling was conducted in a large university in Niteroi-RJ,Brazil,from March 2021 to July *** study population consisted of students,faculty,and administrative staff employed by the university.A total of 3433 faculty members,60703 students,and 3812 administrative staff were invited to *** were gathered through rapid serological tests to detect immunoglobulin(Ig)M and IgG against ***χ²or Fisher's exact test was used to conduct statistical analysis.A 0.20 significance level was adopted for variable selection in a multiple logistic regression model to evaluate *** A total of 1648 individuals were enrolled in the *** proportion of cOVID-19 positivity was 164/1648(9.8%).The adjusted logistic model indicate a positive association between the expression of IgM or IgG and age[odds ratio(OR)=1.16,95%cI:1.02-1.31](Ps who had been in contact with a cOVID-19-positive case(OR=3.49,95%cI:2.34-5.37)(Phose who had received the cOVID-19 vaccine(OR=2.33,95%cI:1.61-3.35)(Psocial isolation(OR=0.59,95%cI:0.41-0.84)(Phe likelihood of sho

关键词： serological surveillance sARs-coV-2 antibodies cOVID-19 serological rapid test Risk factors for cOVID-19

seismic performance and comparison of three different I beam to box column joints

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Earthquake Engineering and Engineering Vibration 2014年第4期13卷 717-729页

作者： Z.saneei nia A.Mazroi M.Ghassemieh h.Pezeshki school of civil Engineering College of Engineering University of Tehran Department of civil Engineering Central Branch of Azad University Building and housing Researching center

Despite the inherently advantages of the box column, finding the best option for the I beam to the box column connection is the main challenge in using the box column as a structural member for special moment frames. In this paper, the seismic performance of urtreinforced connection, weakened connection and strengthened connection was evaluated through a comprehensive experimental program. The seismic comparisons were fabricated by assessing the strength, ductility and energy dissipation in each configuration. Three full scale tests with several connections were carried out. All the specimens were subjected to cyclic loading and prior to failure by forming a plastic hinge in the beam, all the connections managed to reach an inelastic rotation of more than 6.0% rad. The experimental and analytical results showed that the seismic performance of the strengthened connection with flange and shear plates turned out to be the most effective in the beam to the box column connection. Moreover, the normalized stress distribution of the continuity plates revealed that the possibility of the weld fracture in unreinforced connection is more than other specimens.

关键词： box column special moment frame unreinforced connection weakened connection strengthened connection seismic comparison

Enhancing visible-light-driven NO oxidation through molecular‐level insights of dye-loaded sea sands

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Rare Metals 2024年第2期43卷 543-554页

作者： Yu-han Li Bang-Fu chen sónia A.c.carabineiro You-Yu Duan Ping Tan Wing-Kei ho Fan Dong Engineering Research center for Waste Oil Recovery Technology and Equipment Ministry of EducationChongqing Key Laboratory of Catalysis and New Environmental MaterialsChongqing Technology and Business UniversityChongqing400067China Nanchang Institute of Technology Nanchang33044China LAQV-REQUIMTE Department of ChemistryNOVA School of Science and TechnologyUniversidade NOVA de Lisboa2829-516CaparicaPortugal college of Physics and center of Quantum Materials and Devices Chongqing UniversityChongqing401331China Department of science and Environmental studies The Education University of Hong KongHong Kong999077China

Natural minerals,abundant and easily obtained through simple physical processing,offer a cost-effective and environmentally friendly solution for dyeing wastewater disposal and air pollution *** study investigates the photocatalytic removal of NO using natural different types of dyes,loaded on natural sand,under visible light *** examining various coating concentrations of dyes and sand weights,we discovered that sand loaded with Rhodamine B(RhB)exhibits high activity for the photo-oxidation of NO.A combination results of X-ray diffraction(XRD),X-ray photoelectron spectroscopy(XPs),Fourier transform infrared spectroscopy(FTIR)and thermogravimetric(TG)analyses confirm the presence of siO_(2),cacO_(3),Al_(2)O_(3)and iron oxides as the main components of the ***,studying RhB-loaded individual components reveals that cacO_(3)plays a crucial role in enhancing the NO removal *** results and theoretical calculations demonstrate the establishment of a directional charge transfer channel from cacO_(3)to RhB,facilitating the adsorption and activation of molecular NO and O_(2).This work not only promotes the utilization of natural mineral resources but also enriches the fields of environmental photochemistry and semiconductor photocatalysis.

关键词： sand dyes Rhodamine B Photo-oxidation of NO Visible light illumination

Thermogravimetric studies of Deposited Potash Impregnated for Flame-Retardancy into a cotton Fabric

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chinese Journal of chemistry 2007年第7期25卷 926-929页

作者： MOsTAshARI, s.M. nia, Y.K. BALE, s. Department of chemistry Faculty of Science the University of Gilan Rasht lran

The effect of potash as a nondurable finish on the flammability of 100% cotton fabric （plain 180 g/m^2） was investigated. The bone-drled weighed fabrics were dipped into suitable concentrations of potash, with a volume of 100 mL at 20-2℃. The impregnation was followed by means of squeeze rolls and drying at 110 ℃. The samples were then reweighed with analytical precision. After conditioning overnight by using our ＂vertical flame tester＂ the optimum add-on values to impart flame-retardancy to cotton fabric was determined and expressed by 0.80 g of potash per 100 g fabric to be an efficient addition. Thermogravimetric analysis of pure cotton, treated cotton with potash at its optimum efficiency for donation of flame-retardancy into cotton fabric was fulfilled and the thermograms were compared and commented. The effectiveness of this hydroxide was attributed to the heat dissipation by the remaining consumed material during the combustion. The results obtained are in favor of ＂Dust or Wall Effect Theory＂.

关键词： condensed phase retardation dust or wall effect theory flame-retardancy gas theory potash thermogravimetry

catalytic combustion of volatile organic compounds using perovskite oxides catalysts—a review

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Frontiers of chemical science and Engineering 2023年第11期17卷 1649-1676页

作者： shan Wang Ping Xiao Jie Yang sónia Accarabineiro Marek Wiśniewski Junjiang Zhu Xinying Liu Institute for the Development of Energy for African sustainability College of ScienceEngineering and TechnologyUniversity of South AfricaJohannesburg 1710South Africa hubei Key Laboratory of Biomass Fibers and Eco-dyeing&Finishing College of Chemistry and Chemical EngineeringWuhan Textile UniversityWuhan 430200China LAQV-REQUIMTE Department of ChemistryNOVA School of Science and TechnologyUniversidade NOVA de Lisboa2829-516 CaparicaPortugal Physicochemistry of carbon Materials Research Group Faculty of ChemistryNicolaus Copernicus University in Toruń87-100 ToruńPoland Zhijiang college of Zhejiang University of Technology Shaoxing 312030China

With the rapid development of industry,volatile organic compounds(VOcs)are gaining attention as a class of pollutants that need to be eliminated due to their adverse effects on the environment and human *** combustion is the most popular technology used for the removal of VOcs as it can be adapted to different organic emissions under mild *** review first introduces the hazards of VOcs,their treatment technologies,and summarizes the treatment mechanism ***,the characteristics and catalytic performance of perovskite oxides as catalysts for VOc removal are expounded,with a special focus on lattice distortions and surface defects caused by metal doping and surface modifications,and on the treatment of different *** challenges and the prospects regarding the design of perovskite oxides catalysts for the catalytic combustion of VOcs are also *** review provides a reference base for improving the performance of perovskite catalysts to treat VOcs.

关键词： perovskite oxides volatile organic compounds catalytic combustion reaction mechanism

Effects of different friction stir welding conditions on the microstructure and mechanical properties of copper plates

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International Journal of Minerals,Metallurgy and Materials 2016年第7期23卷 799-809页

作者： Ali Alavi nia Ali shirazi Department of Mechanical Engineering Bu-Ali Sina University

Friction stir welding is a new and innovative welding method used to fuse materials. In this welding method, the heat generated by friction and plastic flow causes significant changes in the microstructure of the material, which leads to local changes in the mechanical properties of the weld. In this study, the effects of various welding parameters such as the rotational and traverse speeds of the tool on the microstructural and mechanical properties of copper plates were investigated; additionally, charpy tests were performed on copper plates for the first time. Also, the effect of the number of welding passes on the aforementioned properties has not been investigated in previous studies. The results indicated that better welds with superior properties are produced when less heat is transferred to the workpiece during the welding process. It was also found that although the properties of the stir zone improved with an increasing number of weld passes, the properties of its weakest zone, the heat-affected zone, deteriorated.

关键词： copper friction stir welding mechanical properties microstructure

TENsILE cREEP DEFORMATION AND DAMAGE BEhAVIOR IN A NIcKEL-BAsE sUPERALLOY AT 900℃

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Acta Metallurgica sinica(English Letters) 2004年第4期17卷 606-611页

作者： h.c.Yu s.s.Xie h.c.Yang Beijing Institute of Aeronautical Materials Beijing 100095 ChinaR & D Center Baosteel Co. Ltd. Shanghai 201900 ChinaCollege of Materials and Metallurgy Northeastern University Shenyang 110004 China

The tensile creep deformation and damage evolution in a Ni-base superalloy at 900℃/170MPa were investigated. At the first creep stage, abnormal creep occured due to the resolution of fine particles, and the deformation initiated from grain boundary areas. It is evident that nearly all of the dislocations were in γ matrix channels in form of dislocation pairs and the dislocations were impeded at γ/γ' interfaces, thus the dislocation networks developed deformation. At the steady creep stage, impeded dislocations atγ/γ' interfaces climbed over γ' phases by diffusion-dominant mechanism. At the last creep stage, voids were formed around carbides at grain boundary which leaded to accumulated damage and caused creep rate accelerated. With the dislocation networks being broken, the voids connected and grew into micro-cracks gradually. Finally the cracks propagated along grain boundary area and resulted in failure.

关键词： creep deformation and damage dislocation microstructure su-peralloy

Temperature and Thermal stress Distribution for Metal Mold in squeeze casting Process

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Journal of Materials science & Technology 2008年第3期24卷 347-350页

作者： c.h.Lee s.h.Lee Institute of Technology and science Chung-Ang University

In the squeeze casting process, loaded high pressure （over approximately 200 MPa） and high temperature influence the thermo-mechanical behavior and performance of the used metal mold. Therefore, to safely maintain the metal molds, the thermo-mechanical characteristics （temperature and thermal stress） of metal mold in the squeeze casting must be investigated. In this paper, temperature and thermal stress distribution of steel mold in squeeze casting process were investigated by using a three-dimensional non-steady heat conduction analysis and a three-dimensional thermal elastic-plastic analysis considering temperature-dependent thermophysical and mechanical properties of the steel mold.

关键词： squeeze casting steel mold Thermal stress Thermo-Mechanical analysis