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Use of silica nanopowder to accelerate CO_2 sorption by Ca(OH)_2

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Particuology 2013年第4期11卷 448-453页

作者： M.A.s.Quintanilla J.M.Valverde Faculty of Physics University of SevilleAvenida Reina Mercedes s/n

Promising technologies have recently emerged to capture CO2 from postcombustion flue gas and to enhance the production of hydrogen from natural gas by steam-methane reforming, on the basis of sorp- tion of CO2 by Ca-based powders. The rate of CO2 sorption on Ca-based powders is limited by both carbonation kinetics and transport of CO2 to unreacted sorption sites. Ca-based powders may exhibit cohesive aggregation, thus hindering gas-solids contact efficiency. In our work, we tested the sorption rate of powder samples prepared by dry mixing of a cohesive Ca（OH）2 powder with a silica nanopowder used as additive. The silica nanopowder serves to improve the dispersibility of Ca（OH）2. Consequently, when a CO2 enriched gas and the modified sorbent are brought into contact, the rate of CO2 sorption is enhanced in the initial fast phase of interest for practical applications.

关键词： FluidizationFine powdersCO2 sorptionNanoparticles

Cold metal transfer(CMT) technology-An overview

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Defence Technology（防务技术） 2018年第1期14卷 28-44页

作者： s.selvi A.Vishvaksenan E.Rajasekar Mechanical Engineering Institute of Road and Transport Technology Automobile Engineering Institute of Road and Transport Technology

Cold Metal Transfer technology has revolutionized the welding of dissimilar metals and thicker materials by producing improved weld bead aesthetics with controlled metal deposition and low heat-input. In this study, the process, weld combinations, laser-CMT hybrid welding and applications of CMT welding are critically reviewed. Microstructure and other weld characteristics have been discussed at length for various base metal combinations. Particularly, the welding of aluminium and steel with better results has been possible with CMT Welding. The results reviewed in this article indicate that the CMT-Laser hybrid welding is more preferable to Laser or Laser hybrid welding. CMT welding has found applications in automobile industries, defence sectors and power plants as a method of additive manufacturing.

关键词： Cold metal transfer [CMT]Welding Laser-CMT welding Additive manufacturing Composite joint Metal inert gas[MIg] Metal active gas[MAg]

gETTINg TO THE BOTTOM OF FOOTWEAR CUsTOMIZATION

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Journal of systems science and systems Engineering 2011年第3期20卷 310-322页

作者： Thilina W.WEERAsINgHE Ravindra s.gOONETILLEKE Human Performance Laboratory Department of Industrial Engineering and Logistics ManagementHong Kong University of Science and TechnologyClear Water BayHong KongChina

Footwear have been evaluated mostly using commercially available products, while some researchers have used custom shoes. Hence, the understanding of the effects of various parameters of a shoe is quite limited. The footbed simulator invented in recent years allows a range of parameters to be studied in quiet standing. It can be used to evaluate perceived feel and center of pressure changes to changes in heel height, seat length, material, wedge angle and toe spring. This paper is meant to show the value of the footbed simulator in terms of research and the actual production of shoes. A study performed with two heel heights, three combinations of seat length and material and three wedge angles showed that the perceived feel is closely related to the center of pressure. The results also show the optimum footbed has a significantly different perceived feel. Thus, the footbed simulator is an ideal way to generate custom footwear designs.

关键词： Footwear insole shoe shape footbed wedge angle center of pressure comfort mid-foot stability

Physical aspects of anisotropic compact stars in f(T,T) gravity with off diagonal tetrad

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Chinese Physics C 2021年第8期45卷 190-205页

作者： M.Zubair Allah Ditta g.Abbas Rabia saleem Department of Mathematics COMSATS University IslamabadLahore CampusLahorePakistan Department of Mathematics The Islamia University of BahawalpurBahawalpurPakistan

This study addresses the formation of anisotropic compact star models in the background of f(T,T)gravity(where T and T represent the torsion and trace of the energy momentum tensor,respectively).f(T,T)gravity is an extension of the f(T)theory,and it allows a general non-minimal coupling between T and *** this setup,we apply Krori and Barua's solution to the static spacetime with the components ξ=Br^(2)+c and ψ=Ar^(2).To develop viable solutions,we select a well-known model f(T,T)=αT^(m)+βT+Ф(where α and β are coupling parameters,and Ф indicates the cosmological constant).We adopt the conventional matching of interior and exterior space time to evaluate the unknowns,which are employed in the stellar *** present a comprehensive discussion on the stellar properties to elaborate the anisotropic nature of compact stars corresponding to well-known models:PsRJ1416-2230,4U1608-52,CenX-3,EXO1785-248,and *** physical analysis,it is observed that the solution of compact spheres satisfy the acceptability criteria,and its models behave optimally and depict stability and consistency,in accordance with f(T,T)gravity.

关键词： f(T,T)gravity compact stars stellar models

synthesis and photoluminescence studies of Ba(gd,Ln)B_9O_(16):Eu^(3+)(Ln=La,Y) phosphors for n-UV LED lighting and display devices

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Journal of Rare Earths 2015年第2期33卷 140-147页

作者： V.V.Rangari s.J.Dhoble Department of Physics RTM Nagpur University

BagdB9O16：Eu^3＋ and Ba（gd,Ln）B9O16：Eu^3＋（Ln=La, Y） phosphors were synthesized by solid state diffusion method. The X-ray diffraction, scanning electron microscopy（sEM） and photoluminescence properties were investigated. The as-synthesized BagdB9O16：Eu^3＋ and Ba（gd,Ln）B9O16：Eu^3＋（Ln=La, Y） phosphors showed strong red emission under ultraviolet light excitation. By partially substituting gd^3＋ by La^3＋ and Y^3＋ ions in the host BagdB9O16：Eu^3＋ materials, the maximum emission intensity was observed for the optimum composition of Bagd0.91La0.8B9O16Eu0.01 phosphor. The experimental results indicated that the Eu doped BagdB9O16 and Ba（gd,Ln）B9O16（Ln=La, Y） phosphors were promising red phosphors, which might find potential applications in near-UV excited LED lighting as well as display devices. Comparison of as-synthesized phosphors with standard phosphor used in CFL（compact fluorescent lamp） was also done. Energy transfer mechanism of gd^3＋ to Eu^3＋ was also discussed in this paper.

关键词： phosphor solid state diffusion display devices photoluminescence rare earths

Numerical Investigation of Effect of Inlet swirl and Total-pressure Distortion on Performance and stability of an Axial Transonic Compressor

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Journal of Thermal science 2016年第6期25卷 501-510页

作者： A.Naseri M.Boroomand s.sammak Aerospace Engineering Department Amirkabir University of Technology

This paper represents numerical simulation of flow inside an axial transonic compressor subject to inlet flow distortion,to evaluate its effect on compressor performance and *** types of inlet distortion,namely inlet swirl and total pressure distortion are *** study the effect of combined distortion patterns,different combinations of inlet swirl and total pressure distortion are also *** for cases with total pressure distortion indicate that hub radial distortion improves stability range of the compressor while tip radial distortion deteriorates *** explanation for this observation is presented based on redistribution of flow parameters caused by distortion and the way it interacts with stall inception mechanisms in a transonic axial *** also show that while co-swirl patterns slightly improve stability range of the compressor,counter-swirl patterns diminish *** of combined distortion cases reveals that superimposition of effects of each individual pattern could predict the effect of a combined pattern on compressor's performance within an accuracy of 1%.However,it is unable to predict the associated effect on compressor's stability.

关键词： compressor stall distortion blade inlet axial radial rotor rotating counter

Experimental Investigation of Micro Heat Pipes of Different Cross-sections Having same Hydraulic Diameter

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Journal of Thermal science 2008年第3期17卷 247-252页

作者： s.L.Mahmood M.A.R.Akhanda Department of Mechanical and Chemical Engineering Islamic University of Technology

Effects of micro heat pipe （MHP） cross-sections and orientations on its thermal performance are experimentally investigated in this study. Tests are conducted using five different cross-sections （circular, semicircular, elliptical, semi-elliptical and rectangular） of micro heat pipes having same hydraulic diameter of 3 rnm placed at three different inclination angles （0°, 45°, 90°）, where water is used as the working fluid. Evaporator section of the MHP is heated by an electric heater and the condenser section is cooled by circulation of water in an annular space between condenser section and the water jacket. Temperatures at different locations of the MHP are measured using five calibrated K type thermocouples. Heat supply is varied using a voltage regulator which is measured by a precision ammeter and a voltmeter. It is found that thermal performance tends to deteriorate as the MHP is flattened. Thus among all cross-sections of MHP, circular one exhibits the best thermal performance in terms of heat flux dissipation followed by semi-elliptical, semi-circular, elliptical and rectangular cross-sections. Moreover, its heat transfer capability also decreases with decreasing of its inclination angle. Finally, a correlation is developed which covers all the experimental data within ＋7%.

关键词： Micro heat pipe cross-section hydraulic diameter inclination.

Active vibration control of tensegrity structures for performance enhancement: A comparative study

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Earthquake Engineering and Engineering Vibration 2019年第3期18卷 679-693页

作者： Ou Yaowen Feng Xiaodong Mohammad s. Miah College of Civil Engineering Central South University Changsha China College of Civil Engineering Shaoxing University Shaoxing China College of Civil Engineering and Architecture Zhejiang University Hangzhou China Faculty of Civil Engineering Technische Universitat Dresden-TU Dresden Dresden Germany Department of Civil Engineering University of Asia Pacifi c Dhaka Bangladesh

This study performs a novel control effi ciency assessment approach that compares performance of optimal control algorithms regarding vibration of tensegrity structures. Due to complex loading conditions and the inherent characteristics of tensegrities, e.g. geometrical nonlinearity, the quantization of control effi ciency in active control of tensegrity constitutes a challenging task especially for diff erent control algorithms. As a fi rst step, an actuator energy input, comprising the strain energy of tensegrity elements and their internal forces work, is set to constant levels for the linearquadratic regulator (LQR). Afterwards, the actuator energy of the linear-quadratic gaussian (LQg) is iterated with identical actuator energy input in LQR. A double layer tensegrity grid is employed to compare the control effi ciencies between LQR and LQg with fi ve diff erent control scenarios. The results demonstrate the effi ciency and robustness in reducing the dynamic response of tensegrity structures, and a theoretical guideline is provided to search optimal control options in controlling actual tensegrities.

关键词： tensegrity structures optimal control algorithms control effi ciency actuator placements LQg

skin layer of A380 aluminium alloy die castings and its blistering during solution treatment

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Journal of Materials science & Technology 2019年第9期35卷 1906-1916页

作者： Zihao Yuan Zhipeng guo s.M.Xionga school of Materials science and Engineering Tsinghua UniversityBeijing100084China state Key Laboratory of Automobile safety and Energy Tsinghua UniversityBeijing100084China

skin layer is a characteristic microstructure of aluminium die castings, which would effect the surface blistering during solution treatment. In this study, the microstructures of skin layer were investigated by the methods of optical microscope (OM), scanning electron microscope (sEM) and electron probe microanalyzer (EPMA). High resolution X-ray CT was used to compare the skin layer with normal surface before and after solution treatment. With the aid of computational fluid dynamics (CFD), the formation mechanism of the skin layer was discussed based on microstructure distribution, solute segregation, porosity distribution and surface blistering. The results suggested that the skin layer is related to a succession of complex processes before the filling process finished. Pore clusters or laminar defects would be formed in skin layers during solution treatm ent and cause severe surface blistering.

关键词： skin layer Die castings solution treatment Blistering