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Degree of compaction and compression strength of Nigerian Alfisol under tilled condition and different machinery traffic passes

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International Journal of Agricultural and Biological Engineering 2012年第2期5卷 34-41页

作者： Fasinmirin Johnson Toyin Adesigbin Adedayo Joseph Department of Agricultural Engineering Federal University of TechnologyAkureNigeria

Information on the effect of soil compaction on soil mechanical properties such as degree of compaction,compression and shear strength of tropical soils of Nigeria under different machinery traffic passes is very *** experiment was conducted in a tilled and compacted sandy clay loam(Alfisol)in Akure,Nigeria,under different machinery traffic passes to determine compaction effects on bulk density,compression strength,degree of compaction and the shear strength of *** plots,A,B,C and D of area 20 m×50 m each were used for the field *** plot A was tilled with a tractor-mounted disc plough,and the remaining three plots:B,C and D were subjected to 5,10 and 15 to and fro passes,respectively,using heavy duty Mercy Fergusson tractor model 4355(3.82 Mg).The treatments were replicated three times in a randomized complete block *** plots progressively increased the bulk density from 1.63 g/cm^(3) to 1.90 g/cm^(3),but the highest bulk density was observed in plots under 15 traffic passes with the value of(1.90±0.23)g/*** percentage of soil compaction varies from 90.5%to 97%at the 0-10 cm soil *** compression strength of soil increased from 31.00 kPa to 42.05 kPa and from 29.68 to 65.44 kPa at the 0-10 cm and 10-20 cm soil layers,respectively,which resulted in the increased shear strength from 15.79 kPa to 21.03 kPa and 14.8 kPa to 32.72 kPa at the 0-10 cm and 10-20 cm in plots under 5 and 15 traffic passes,*** A(tilled soil)had the lowest bulk density,degree of compaction and compression strength with values(1.51±0.19)g/cm^(3),88.2%,and(12.15±0.37)kPa,respectively,and consequently the lowest shear strength of(6.02±1.23)kPa,which enhanced air movement and microbial activities in the *** under 15 traffic passes,especially at the 10-20 cm soil layer,may result in poor root penetration when cropped but can be very reliable and consistent when used for structural purposes.

关键词： soil compaction tillage degree of compaction compression strength shear strength farm machine traffic passes bulk density

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Microstructures and electrochemical behaviors of casting magnesium alloys with enhanced compression strengths and decomposition rates

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Journal of Magnesium and Alloys 2023年第4期11卷 1213-1223页

作者： Xuewu Li Qingyuan Yu Xi Chen Qiaoxin Zhang State Key Laboratory of Tribology Tsinghua UniversityBeijing 100084China School of Mechanical Engineering Xi’an University of Science and Technology58 Yanta RoadXi’an 710054China School of Mechanical and Electronic Engineering Wuhan University of Technology122 Luoshi RoadWuhan 430070China

New-type magnesium alloy with prominent solubility and mechanical property lays foundation for preparing fracturing part in petroleum ***,Mg-xZn-Zr-SiC alloy is prepared with casting *** and compression tests are conducted to assess the feasibility as decomposable ***,composition,phase and distribution are characterized to investigate decomposition *** indicate that floccule,substrate component and reticulate secondary phase are formed on as-prepared *** also acts out enhanced compression strength to maintain pressure and guarantee stability in dissolution ***,as decomposition time and zinc content increase,couple corrosion intensifies,resulting in gradually enhanced decomposition *** sample decomposition is mainly due to basal anode dissolution,micro particle exfoliation and poor decomposition resistance of corroding *** work shows profound significance in preparing new-type accessible alloy to ensure rapid dissolution of fracturing part and guarantee stable compression strength in oil-gas reservoir exploitation.

关键词： Magnesium alloy Corrosion dissolution compression strength Electrochemical test Decomposition mechanism

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Effects of sintering temperature and time on defect evolution and compression properties of Ti-Al_(3)Ti laminated composites

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Chinese Journal of Aeronautics 2022年第1期35卷 137-143页

作者： Meini YUAN Zhijun WANG Fangzhou HAN College of Mechatronic Engineering North University of ChinaTaiyuan 030051China

For metal-intermetallic laminated composites,various types of defects often occur during the preparation *** paper studied the evolution and formation mechanism of defects,such as pores,tunnel cracks,and delamination cracks in Ti-Al_(3)Ti laminated composites prepared by vacuum hot-pressing ***,quasi-static and dynamic compression tests were performed to study the effects of pores and delamination cracks on the compression properties of the *** results showed that for Ti-Al_(3)Ti laminated composites prepared at 710℃,their Al_(3)Ti layers exhibit a porous structure,and the porosity of Al_(3)Ti layers firstly decreases and then increases under the combined action of press,the self-propagating reaction and Al3Ti grain *** tunnel cracks in Ti-Al_(3)Ti laminated composites are resulted by tensile residual stresses and the inherent brittleness of *** Ti-Al_(3)Ti laminated composites prepared at 680°C,the formation of delamination cracks is mainly related to the diffuse reaction of Ti/Al atoms and the Kirkendall effect,and the numbers of delamination cracks increase with the increasing of sintering ***,the pores and delamination cracks greatly deteriorate the compression properties of Ti-Al_(3)Ti laminated ***-free and dense Ti-Al_(3)Ti laminated composites exhibit the highest compression properties.

关键词： compression strength Cracks Diffusion coefficients Laminated composites Scanning electron microscopy

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Influence of Spark Plasma Sintering Temperature on the Densification, Microstructure and Mechanical Properties of Al-4.5 wt.%Cu Alloy

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Acta Metallurgica Sinica(English Letters) 2013年第6期26卷 761-771页

作者： S.Devaraj S.Sankaran R.Kumar Department of Metallurgical and Materials Engineering Indian Institute of Technology Madras (IIT Madras)

The effect of sintering temperature on the densification mechanisms, microstructural evolution and mechanical properties of spark plasma sintered （SPS） compacts of a gas atomized Al-4.5 wt.%Cu alloy was investigated. The powder particles whose size varied between 10 to 500μm was subjected to SPS at 400, 450 and 500℃ at a pressure of 30 MPa. The compact sintered at 500℃ exhibited fully dense microstructure which was characterized by a uniform distribution of the secondary phase, free of dendrites and micro-porosity. Microscopy and the SPS data reveal that the events such as particle rearrangement, localized deformation and bulk deformation appear to be the sequence of sintering mechanisms depending on the size range of powder particles used for consolidation. The compact sintered at 500℃ exhibited the highest hardness and compression strength since the microstructure was characterized by fine distribution of precipitates, large fraction of submicron grains and complete metallurgical bonding.

关键词： Spark plasma sintering Sintering mechanisms Precipitation compression strength

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Comparative study of static and dynamic parameters of rock for the Xishan Rock Cliff Statue

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2011年第10期12卷 771-781页

作者： Jin JIANG Jin-zhong SUN School of Civil and Environmental Engineering Nanyang Technological University 639798 Singapore School of Engineering and Technology China University of Geosciences Beijing 100083 China

Ultrasonic wave testing was applied to investigate the quality and weathering status of rock specimens obtained in two borings situated in the Xishan Buddha rock slope in Taiyuan, China. This paper pays special attention to the distribution of bulk density, dynamic parameters and static parameters of rock specimens as well as the relationship between static and dynamic parameters. The results illustrate that the distribution of both parameters is identical along the depth of two drilled holes in the rock slope. When the hole depth increases, the density of rock mass, saturated compression strength and static elastic modulus, dynamic elastic modulus and wave velocity also show increase tendency. The weathering degree in the rock mass ranging from the surface of cliff to the depth of 2.5 m is the highest while the rock mass is unsalted and more rigid when the depth is larger than 3.0 m. The relationship between dynamic elastic modulus, sonic wave velocity and horizontal depth indicates that dynamic elastic modulus is more sensitive than sonic wave velocity. Conversely, by comparing quantity relationship between static elastic modulus and sonic wave velocity, it is found that the composition of rock has a great influence on the relationship between static and dynamic parameters, that is, inequality of rock composition will lead to dispersion and abnormality of the distribution of static and dynamic parameters.

关键词： Xishan Buddha Rock mechanics Rock quality Elastic wave velocity Elastic modulus compression strength Ultrasonic wave testing

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Microstructure and mechanical property of Mg-10Gd-2Y-1.5Zn-0.5Zr alloy processed by eight-pass equal-channel angular pressing

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Rare Metals 2023年第4期42卷 1371-1377页

作者： Huan Liu Jia Ju Xiao-Wei Yang Yu-Hua Li Jing-Hua Jiang Ai-Bin Ma College of Mechanics and Materials Hohai UniversityNanjing211100China Suqian Research Institute of Hohai University Suqian223800China College of Materials Engineering Nanjing Institute of TechnologyNanjing211167China

In this work,a high-strength Mg-10Gd-2Y-1.5Zn-0.5Zr(wt%)alloy was prepared via eight passes of equal-channel angular pressing(ECAP).The microstructures and mechanical properties of as-cast and ECAP alloys were systematically investigated by X-ray diffraction(XRD),optical microscopy(OM),scanning electron microscopy(SEM),transmission electron microscopy(TEM)and electronic universal testing *** obtained results indicate that the microstructure of as-cast alloy consists ofα-Mg dendrite,network Mg3(Gd,Y,Zn)phase and lamellar 14H long-period stacking ordered(LPSO)phase which is precipitated near the boundary of Mg3(Gd,Y,Zn)*** eight-pass ECAP,the network Mg3(Gd,Y,Zn)phase is deformed and ***,the refined Mg_3(Gd,Y,Zn)particles are not distributed uniformly in the matrix,but still aggregated at the interdendritic ***,the content of 14H lamellas increases obviously,and they become bent and kinked during severe *** is activated in the region between Mg3(Gd,Y,Zn)particles and 14H *** test at room temperature indicates that the ECAP alloy exhibits excellent mechanical property with compressive strength of 518 MPa and fracture strain of 21.6%.The comprehensive high strength and toughness could be ascribed to the refined Mg_3(Gd,Y,Zn)particles,DRX grains and kinked 14H LPSO phase.

关键词： Mg-Gd-Y-Zn-Zr Long-period stacking ordered phase Equal-channel angular pressing compression strength Fracture strain

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Mechanical properties characterization of different types of masonry infill walls

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Frontiers of Structural and Civil Engineering 2020年第2期14卷 411-434页

作者： Andre FURTADO Hugo RODRIGUES Antonio AREDE Humberto VARUM CONSTRUCT-LESE Department of Civil EngineeringFaculty of EngineeringUniversity of PortoPorto 4200-465Portugal R1SCO School of Technology and ManagementPolytechnic Institute of LeiriaLeiria 2411-901Portugal

It is remarkable,the recent advances concerning the development of numerical modeling frameworks to simulate the infill panels'seismic ***,there is a lack of experimental data of their mechanical properties,which are of full importance to calibrate the numerical *** primary objective of this paper is to present an extensive experimental campaign of mechanical characterization tests of infill masonry walls made with three different types of masonry units:lightweight vertical hollow concrete blocks and hollow clay *** different types of experimental tests were carried out,namely:compression strength tests,diagonal tensile strength tests,and flexural strength tests parallel and perpendicular to the horizontal bed joints.A total amount of 80 tests were carried out and are reported in the present *** second objective of this study was to compare the mechanical properties of as-built and existing infill *** results presented and discussed herein,will be in terms of strain-stress curves and damages observed within the *** was observed a fragile behavior in the panels made with hollow clay horizontal bricks,without propagation of *** plaster increased the flexural strength by 57%.

关键词： masonry infill walls experimental characterization compression strength shear diagonal strength flexural strength

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Preparation of Phlogopite-based Geopolymer and Its Surface Nonpolar Modification

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Journal of Wuhan University of Technology(Materials Science) 2021年第3期36卷 433-438页

作者： LIN Weiqing LUO Wenjun ZHANG Guanghui LI Haifeng School of Civil Engineering and Architecture Wuhan University of TechnologyWuhan 430070China Faculty of Material Science and Chemistry China University of GeosciencesWuhan 430074China The State Key Laboratory of Refractories and Metallurgy Wuhan University of Science and TechnologyWuhan 430081China

Phlogopite-based geopolymer was first prepared successfully under the activation of lye by compression molding at 50 MPa for 1 *** geopolymer was endowed with nonpolar surface via brushing modified liquid at room ***-cooked dirty oil,whose main component was fatty acid,was used as nonpolar *** raw materials and geopolymer samples were characterized by XRD,FT-IR and *** compression strength of 7-day specimen run up to 36.8 MPa and its surface static water contact angle could reach 132°.The solubility of phlogopite powder directly affected the compressive strength of geopolymers and the evaluation index of mechanical strength of geopolymer based on the solubility of phlogopite powder was proposed.

关键词： phlogopite geopolymer nonpolar modification solubility compression strength

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A zirconium carbide coating on graphite prepared by reactive melt infiltration

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Journal of Central South University 2014年第2期21卷 472-476页

作者：杨鑫苏哲安黄启忠柴立元钟平薛亮 School of Metallurgical Science and Engineering Central South University State Key Laboratory of Powder Metallurgy (Central South University)

A dense ZrC coating with the thickness of 130 μm is prepared on graphite by reactive melt *** and SEM analyses show that the phase composition of the coating is ZrC and it adheres well with the *** influence of ZrC coating on mechanical properties of the graphite was investigated by compression tests and the results show that after the coating process,the compression strength of the coated sample is improved by 13.64% as compared with graphite *** improvement of the compression strength for ZrC coated sample can be associated to the increased density and the ZrC particle reinforcement due to the infiltration and reaction of the melted Zr with carbon substrate in the coating process.

关键词： graphite compression strength coating ZrC

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Microstructure and mechanical property of a high-strength Mg-10Gd-6Y-1.5Zn-0.5Zr alloy prepared by multi-pass equal channel angular pressing

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Journal of Magnesium and Alloys 2017年第2期5卷 231-237页

作者： Huan Liu He Huang Xiaowei Yang Cheng Li Jingli Yan Jinghua Jiang Aibin Ma College of Mechanics and Materials Hohai UniversityNanjing 211100China Ocean and Coastal Engineering Research Institute Hohai UniversityNanjing 226300China College of Materials Science and Engineering Southeast universityNanjing 211189China

In this work,a high-strength Mg–10Gd–6Y–1.5Zn–0.5Zr(wt.%)alloy was fabricated by successive multi-pass equal channel angular pressing(ECAP).The microstructure and mechanical property of as-cast and ECAP alloys were systematically researched by X-ray diffractometer,scanning electron microscopy,transmission electron microscopy and compression *** results show that the microstructure of as-cast alloy consists ofα-Mg grains,Mg24Y5 networks,18R blocks,fine 14H lamellas,and fewY-rich *** 8 passes ECAP,dynamic recrystallization ofα-Mg is developed and their average grain size decreases to about 1μ*** network Mg_(24)Y_(5) phase at grain boundaries is broken into small particles with average diameter lower than 0.5μ***,18R blocks are kinked and delaminated,or broken into small particles and blended with Mg24Y5 particles.14H lamellas grow gradually or are dynamically precipitated within certainα-Mg *** tests indicate that 8p ECAP alloy exhibits excellent mechanical property with compressive strength of 537 MPa and fracture strain of 17.0%.The significant improvement for both strength and ductility of deformed alloy could be ascribed to DRX grains,refined Mg24Y5 particles,18R kinking and dynamical precipitation of 14H.

关键词： Mg-10Gd-6Y-1.5Zn-0.5Zr LPSO phase Equal channel angular pressing compression strength Fracture strain

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