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Journal of Thermal Science 2024年第2期33卷 509-521页

作者： Mojtaba TAHERI Fathollah POURFAYAZ Roghayeh HABIBI akbar maleki Department of Renewable Energies and Environment Faculty of New Sciences and TechnologiesUniversity of TehranTehran***Iran Faculty of Mechanical Engineering Shahrood University of TechnologyShahrood***Iran

Thermal energy storage(TES) is of great importance in solving the mismatch between energy production and *** this regard,choosing type of Phase Change Materials(PCMs) which are widely used to control heat in latent thermal energy storage systems,plays a vital role as a means of TES ***,this field suffers from lack of a comprehensive investigation on the impact of various PCMs in terms of *** address this issue,in this study,in addition to indicating the melting temperature and latent heat of various PCMs,the exergy destruction and exergy efficiency of each material are estimated and compared with each ***,in the present work the impact of PCMs mass and ambient temperature on the exergy efficiency is *** results proved that higher latent heat does not necessarily lead to higher exergy ***,to obtain a suitable exergy efficiency,the specific heat capacity and melting temperature of the PCMs must also be *** to the results,LiF-CaF_(2)(80.5%:19.5%,mass ratio) mixture led to better performance with satisfactory exergy efficiency(98.84%) and notably lower required mass compared to other ***,the highest and lowest exergy destruction are belonged to GR25 and LiF-CaF_(2)(80.5:19.5) mixture,respectively.

关键词： exergy analysis phase change materials thermal energy storage exergy efficiency

Probabilistic stability of uncertain composite plates and stochastic irregularity in their buckling mode shapes:A semi-analytical non-intrusive approach

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Frontiers of Structural and Civil Engineering 2023年第2期17卷 179-190页

作者： Arash Tavakoli maleki Hadi PARVIZ akbar A.KHATIBI Mahnaz ZAKERI Advanced Structures Research Laboratory K.N.Toosi University of TechnologyTehran 16569-83911Iran Faculty of New Sciences and Technologies University of TehranTehran 16569-83911Iran School of Engineering RMIT UniversityMelbourne VIC 3001Australia

In this study,the mechanical properties of the composite plate were considered Gaussian random fields and their effects on the buckling load and corresponding mode shapes were studied by developing a semi-analytical nonintrusive *** random fields were decomposed by the Karhunen−Loève *** strains were defined based on the assumptions of the first-order and higher-order shear-deformation *** equations of motion were extracted using Euler-Lagrange *** probabilistic response space was obtained by employing the nonintrusive polynomial chaos ***,the effect of spatially varying stochastic properties on the critical load of the plate and the irregularity of buckling mode shapes and their sequences were studied for the first *** findings showed that different shear deformation plate theories could significantly influence the reliability of thicker plates under compressive *** is suggested that a linear relationship exists between the mechanical properties’variation coefficient and critical loads’variation ***,in modeling the plate properties as random fields,a significant stochastic irregularity is obtained in buckling mode shapes,which is crucial in practical applications.

关键词： uncertain composite plate stochastic assume mode method Karhunen−Loève theorem polynomial chaos approach plate buckling irregularity in buckling mode shapes

Analysis of factors affecting diagonal tension and compression capacity of corner joints in furniture frames fabricated with dovetail key

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Journal of Forestry Research 2013年第1期24卷 155-168页

作者： Mosayeb Dalvand Ghanbar Ebrahimi akbar Rostampour Haftkhani Sadegh maleki Department of Wood and Paper Science and Technology Faculty of Natural ResourcesUniversity of TehranKarajIran.

This study was conducted to analyze the effect of joint type, and numbers and types of dovetail keys on diagonal tension and compression performance of corner joints in a furniture frame. Joint members were cut from white fir lumber. Butted and mitered joints were constructed with one and two dovetail key（s） with butterfly and H shapes. Joints were glued by polyvinyl acetate （PVAc） and cynoacrylate （CA）. Compression capacity of joints was higher than diagonal tension. Mitered joints were stronger than butted ones. Butterfly dovetail keys were superior to H shape keys. Double keys performed better than single key. Experimental joints glued with PVAc were stronger than those glued with CA glue and control specimens. In terms of strength, butterfly dovetailed joints were comparable with doweled joints.

关键词： diagonal tension diagonal compression dovetail key joints lumber

Bending moment resistance of corner joints constructed with spline under diagonal tension and compression

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Journal of Forestry Research 2012年第3期23卷 481-490页

作者： Sadegh maleki akbar Rostampsour Haftkhani Mosayeb Dalvand Mehdi Faezipour Mehdi Tajvidi Department of Wood and Paper Science and Technology College of Natural ResourcesUniversity of TehranKaraj 31587-77878Iran

We determined the effects of the penetration depth and spline material and composite material type as well as joining method on bending moment resistance under diagonal compression and tension in common wood panel structures. Composite materials were laminated medium density fiberboard （MDF） and particleboard. Joining methods were butt and miter types. Spline materials were high density fiberboard （HDF）. The penetration depths of plywood, wood （Carpinus betolus） and spline were 8, 11 and 14 mm. The results showed that in both diagonal com- pression and tension, MDF joints are stronger than particleboard joints, and the bending moment resistance under compression is higher compared with that in tension. The highest bending moment resistance under tension was shown in MDF, butt joined using plywood spline with 8 mm penetration depth, whereas under compression bending moment resistance was seen in MDF, miter joined with the HDF spline of 14 mm penetration depth.

关键词： Penetration depth composite material type joining type bending moment resistance