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A Review of Basic Mechanical Behavior of Laminated Bamboo Lumber

Journal of Renewable Materials 2022年第2期10卷 273-300页

作者： Assima Dauletbek Haitao Li Rodolfo Lorenzo Ileana Corbi Ottavia Corbi mahmud ashraf College of Civil Engineering Nanjing Forestry UniversityNanjing210037China Joint International Research Laboratory for Bio-Composite Building Materials and Structures Nanjing Forestry UniversityNanjing210037China University College London LondonWC1E 6BTUK University of Naples Federico II Naples80133Italy Deakin University GeelongVIC 3216Australia

Over the past decade,the physical and mechanical performances of laminated bamboo lumber(LBL)–a bamboo-based structural material,have been extensively studied using experimental,analytical,and numerical *** paper presents a review of existing knowledge in the literature about the mechanical properties of *** paper involved the review of the response of LBL to different types of loading such as tension,bending,compres-sion,and *** on results of the literature reviewed,the strength of LBL parallel to grain was 90–124 MPa with MOE of 10700 MPa in tension,29.55–72.60 MPa,and MOE of 8396–11022 MPa in compression,63.87–128.4 MPa,and MOE of 8320–10912 MPa in bending,and 7.15–17.5 MPa in *** average strength of LBL was similar and in some cases exceeded the average values of bamboo-or wood-based materials,while the variability of its mechanical parameters was *** variability in strength values of LBL was affected by bamboo species,density and thickness of bamboo strips,growth portion,type of treatment,strips arrange-ments,and type of adhesive which in turn calls for classification of LBL by strength grades,degree of hardness,the capability of impregnation and penetration,as well as by areas of application in *** study pro-vided and discussed concluding observations,the current research gap,and future research directions on the mechanical properties of LBL.

关键词： Laminated bamboo lumber mechanical properties composites

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Comparative Study on Various Strength Parameters of Structural Elements Made from Cross-Laminated Timber

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Journal of Renewable Materials 2022年第6期10卷 1575-1606页

作者： Mohammad Anwar-Us-Saadat Janeshka Goonewardena Bidur Kafle mahmud ashraf Mahbube Subhani School of Engineering Technology-Civil Melbourne PolytechnicEpping3076Australia School of Engineering Deakin UniversityWaurn Ponds3216Australia

Cross laminated timber(CLT)is an innovative and environment friendly engineered timber product with superior structural *** offers strong resistance against both in-plane and out-of-plane ***,it is widely used as floors,roofs or wall *** experimental research on CLT under various loading conditions has been done in the recent *** article presents a comprehensive review of various design methods to determine basic mechanical properties such as tension,compression and rolling shear strength of CLT with primary focus on Norway *** relevant experimental data available from existing literature were collated and consequently been used to evaluate the performance of various methods to design CLT *** comparison revealed that different methods show considerable variance in predicting the capacity of CLT panels due to the variation in timber species,which affects the corresponding mechanical properties of the *** addition to species,rolling shear properties can also vary considerably depending on the type of experimental technique used for testing.A predictive model has also been proposed to correlate rolling shear strength obtained from shear analogy method to that obtained using planar shear.

关键词： Cross-laminated timber mass timber mechanical strength rolling shear strength planar shear test short span bending test

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Structural behavior of intermediate length cold-formed steel rack columns with C-stitches

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Frontiers of Structural and Civil Engineering 2019年第4期13卷 937-949页

作者： M. ANBARASU mahmud ashraf Department of Civil Engineering Government College of Engineering Salem 636011 India School of Engineering Deakin University Geelong VIC 3216 Australia

This article presents an experimental and numerical investigation on the strength and performance of intermediate length rack column sections with C-stitches under axial compression. The test program consisted of 10 axial concentric compression tests on columns with and without C-stitches under pin end conditions for two different geometric lengths. Finite element (FE) models were developed using commercial FE package ABAQUS considering material and geometric nonlinearities as well as initial geometric imperfections. The elastic buckling properties of the section were calculated using readily available linear elastic buckling analysis tools based on Generalized Beam Theory (GBT) and Finite Strip Method (FSM). Obtained FE results were compared with those obtained experimentally, and once verified the developed FE modeling technique was used to carry out a parametric study to examine changes in structural response due to variations in length, depth and spacing of C-stitches. Observed influences of C-stitches on the behavior and resistance of the considered columns were carefully analyzed, and key design aspects are presented herein.

关键词： cold-formed steel columns C-stitches intermediate length columns distortional buckling

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Properties and Applications of Bamboo Fiber—A Current-State-of-the Art

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Journal of Renewable Materials 2022年第3期10卷 605-624页

作者： Chen Chen Haitao Li Assima Dauletbek Feng Shen David Hui Milan Gaff Rodolfo Lorenzo Ileana Corbi Ottavia Corbi mahmud ashraf College of Civil Engineering Nanjing Forestry UniversityNanjing210037China Joint International Research Laboratory for Bio-Composite Building Materials and Structures Nanjing Forestry UniversityNanjing210037China Jiangsu Fiber Composite Co. Ltd.Yancheng224700China Department of Mechanical Engineering University of New OrleansLos Angeles70148USA Department of Wood Processing Faculty of Forestry and Wood SciencesCzech University of Life Sciences PragueSuchdol16521Czech Republic University College London LondonWC1E 6BTUK University of Naples Federico II Naples80133Italy Deakin University GeelongWaurn PondsVIC 3216Australia

Fibers are used in many forms in engineering applications–one of the most common being used as *** to its renewable short natural growth cycle and abundance of bamboo resources,bamboo fiber has attracted attention over other natural *** fiber has a complex natural structure but offers excellent mechanical properties,which are utilized in the textile,papermaking,construction,and composites ***,bam-boo fibers can easily absorb moisture and are prone to corrosion limiting their use in engineering ***,a better understanding of bamboo fiber is particularly *** paper reviews all existing research on the mechanical characterization of bamboo fiber with an emphasis on the extraction and treatment techniques,and their effect on relevant *** chemical composition of bamboo fibers has also been thoroughly investigated and presented *** applications and future opportunities for bamboo fibers in various fields have been presented with a focus on research *** work can serve as a reference for future research on bamboo fiber.

关键词： Bamboo fiber chemical composition structure production method properties application

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A Review on Strengthening of Timber Beams Using Fiber Reinforced Polymers

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Journal of Renewable Materials 2022年第8期10卷 2073-2098页

作者： Bingyu Jian Ke Cheng Haitao Li mahmud ashraf Xiaoyan Zheng Assima Dauletbek Mahdi Hosseini Rodolfo Lorenzo Ileana Corbi Ottavia Corbi Kun Zhou College of Civil Engineering Nanjing Forestry UniversityNanjing210037China Joint International Research Laboratory for Bio-Composite Building Materials and Structures Nanjing Forestry UniversityNanjing210037China Wu Yuzhang Honors College Sichuan UniversityChengdu610200China Deakin University GeelongVIC 3216Australia University College London LondonWC1E 6BTUK University of Naples Federico II Naples80133Italy Guangxi Lvjing Bamboo Industry Co. Ltd.Guilin541402China

Fiber reinforced polymer(FRP)has been used in the construction industry because of its advantages such as high strength,light weight,corrosion resistance,low density and high *** paper presents a review of bonding techniques adopted to strengthen timber beams using FRP to achieve larger *** methods of bonding between FRP and timber beams have been summarized with a focus on the influencing factors and their effects as well as relevant bond-slip models proposed for fundamental *** investigations to evaluate the flexural performance of timber beams strengthened by FRP bars,sheets and wraps have also been critically reviewed to identify key influencing *** research available on the shear performance of FRP reinforced timber beams have been analyzed to determine the influencing factors of the shear performance in timber-FRP *** paper finally presents an overall summary of the current-state-of-the-art and proposes some future research directions in the field.

关键词： Fiber reinforced polymer(FRP) timber beams retrofitting engineered timber flexural properties

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Effects of Freeze-Thaw Cycles on Physical and Mechanical Properties of Glulam Exposed to Outdoor Environment

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Journal of Renewable Materials 2021年第7期9卷 1293-1307页

作者： Ruyuan Yang Haitao Li Assima Dauletbek mahmud ashraf Rodolfo Lorenzo Youfu Sun Yuehong Wu College of Materials Science and Engineering Nanjing Forestry UniversityNanjingChina College of Civil Engineering Nanjing Forestry UniversityNanjingChina University College London LondonWC1E 6BTUK School of Engineering Deakin UniversityGeelongVIC 3216Australia

This paper presents an experimental investigation to identify suitable indices to assess durability of glulam when subjected to freeze-thaw cycles in an exposed *** this study,two types of glulam specimens were tested for their performance when subjected to different levels of aging due to freezing and *** of aging treatment on various parameters including thickness swelling rate,static bending strength,elastic modulus,shear strength,and peeling rate of adhesive layer were *** results showed that freeze-thaw aging treatment did not affect the water-resistance of the specimens as measured by thickness swelling rate and had little effect on the dimensional stability of the ***,the applied aging treatment weakened the bending resistance of the glulam specimens with more pronounced effects on on low-density *** the other hand,bond strength of high-density wood was relatively more affected due to the appliedfreeze-thaw *** highdensity wood,it is suggested that the shear strength of the adhesive layer be taken as an important index to determine the durability of freeze-thaw cycles *** low-density wood,on the other hand,the static bending strength can be used as an index to determine the durability of glulam under freeze-thaw cycles aging.

关键词： Freeze-thaw cycles structural glulam durability wood failure percentage accelerated aging

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Evaluation of soil loss severity and ecological restoration approach for sustainable agriculture in the Hindu Kush, Karakoram and Himalaya region

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Journal of Mountain Science 2024年第5期21卷 1509-1521页

作者： Arshad ashraf Imran AHMAD Climate Energy and Water Research InstituteNational Agricultural Research Centre(NARC)Islamabad 44000Pakistan

Soil erosion has resulted in removal of the topsoils containing fine soil particles and plant nutrients, causing decrease in soil fertility in the Hindu Kush, Karakoram and Himalaya(HKH) region. The existing production of cereal crop grains has been reduced to one third of the potential crop grains production owing to land degradation and poor farming practices. It is necessary to assess risk of soil loss and identify appropriate controlling measures to address issues of low agriculture productivity and water insecurity in the region. In the present study, severity of soil loss was predicted using Revised Universal Loss Equation(RUSLE) and ecological measures were identified for sustainable mountain agriculture in the HKH region of Upper Indus Basin, Pakistan. Overall 62.6% area was found to have very low risk of soil loss, i.e., 100 t/(ha·yr) in about 6.8% and 7.4% areas respectively. The mean rate of soil loss was about 41.9 t/(ha·yr) in the Hindu Kush, 31.1 t/(ha·yr) in the Himalayas, 18.8 t/(ha·yr) in the Karakoram and overall 29.7 t/(ha·yr) in the three HKH ranges. As such no considerable measures have been adopted by the communities for restoration of the degraded areas except raising fruit/farm trees and supporting limited social forestry for their livelihoods. The slopes cleared for cultivation and susceptible to erosion may be stabilized through sowing/planting of multi-purpose plant species and formation of proper bench terraces. The conservation of forest ecosystem and pastures at higher elevations would help in reducing overland water flow, risk of flash flood hazard and minimizing sediment loads in the downstream. It is essential to adopt site-specific resource conservation techniques and restore possible ecosystem health for sustainable agriculture and economic developm

关键词： Climate change Erodibility Indus basin Land degradation Slope stabilization

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A Game-Theoretic Approach to Safe Crowd Evacuation in Emergencies

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Computers, Materials & Continua 2024年第4期79卷 1631-1657页

作者： Maria Gul Imran Ali Khan Gohar Zaman Atta Rahman Jamaluddin Mir Sardar Asad Ali Biabani May IssaAldossary Mustafa Youldash ashraf Saadeldeen Maqsood mahmud Asiya Abdus Salam Dania Alkhulaifi Abdullah AlTurkey31Department of Computer Science COMSATS University IslamabadAbbottabad CampusAbbottabad22010Pakistan Department of Computer Science Abbottabad University of Science and TechnologyAbbottabad22010Pakistan Department of Computer Science College of Computer Science and Information TechnologyImam Abdulrahman Bin Faisal UniversityP.O.Box 1982Dammam31441Saudi Arabia Science and Technology Unit Umm Al-Qura UniversityMakkah21955Saudi Arabia Deanship of Scientific Research Umm Al-Qura UniversityMakkah21955Saudi Arabia Department of Computer Information Systems College of Computer Science and Information TechnologyImam Abdulrahman Bin Faisal UniversityP.O.Box 1982Dammam31441Saudi Arabia Department of Computer Engineering College of Computer Science and Information TechnologyImam Abdulrahman Bin Faisal UniversityP.O.Box 1982Dammam31441Saudi Arabia Department of Computer Science Faculty of Computer Science and Information TechnologyOmdurman Islamic UniversityOmdurman14415Sudan Business Analytic Program Department of Management and MarketingCollege of Business AdministrationUniversity of BahrainSakhir32038Bahrain

Obstacle removal in crowd evacuation is critical to safety and the evacuation system efficiency. Recently, manyresearchers proposed game theoreticmodels to avoid and remove obstacles for crowd evacuation. Game theoreticalmodels aim to study and analyze the strategic behaviors of individuals within a crowd and their interactionsduring the evacuation. Game theoretical models have some limitations in the context of crowd evacuation. Thesemodels consider a group of individuals as homogeneous objects with the same goals, involve complex mathematicalformulation, and cannot model real-world scenarios such as panic, environmental information, crowds that movedynamically, etc. The proposed work presents a game theoretic model integrating an agent-based model to removethe obstacles from exits. The proposed model considered the parameters named: (1) obstacle size, length, andwidth, (2) removal time, (3) evacuation time, (4) crowd density, (5) obstacle identification, and (6) route *** proposed work conducts various experiments considering different conditions, such as obstacle types, obstacleremoval, and several obstacles. Evaluation results show the proposed model’s effectiveness compared with existingliterature in reducing the overall evacuation time, cell selection, and obstacle removal. The study is potentially usefulfor public safety situations such as emergency evacuations during disasters and calamities.

关键词： Safe crowd evacuation public safety emergency transition probability cooperation

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Wave propagation of a functionally graded plate via integral variables with a hyperbolic arcsine function

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Earthquake Engineering and Engineering Vibration 2024年第3期23卷 547-561页

作者： Mokhtar Ellali Mokhtar Bouazza ashraf M.Zenkour Smart structures Laboratory University of Ain TemouchentAin Temouchent 46000Algeria Department of Civil Engineering University Tahri Mohamed of BecharBechar 08000Algeria Department of Mathematics Faculty of ScienceKing Abdulaziz UniversityJeddah 21589Saudi Arabia Laboratory of Materials and Hydrology(LMH) University of Sidi Bel AbbesSidi Bel Abbes 22000Algeria Department of Mathematics Faculty of ScienceKafrelsheikh UniversityKafrelsheikh 33516Egypt

Several studies on functionally graded materials(FGMs)have been done by researchers,but few studies have dealt with the impact of the modification of the properties of materials with regard to the functional propagation of the waves in *** work aims to explore the effects of changing compositional characteristics and the volume fraction of the constituent of plate materials regarding the wave propagation response of thick plates of *** model is based on a higher-order theory and a new displacement field with four unknowns that introduce indeterminate integral variables with a hyperbolic arcsine *** FGM plate is assumed to consist of a mixture of metal and ceramic,and its properties change depending on the power functions of the thickness of the plate,such as linear,quadratic,cubic,and inverse *** utilizing Hamilton’s principle,general formulae of the wave propagation were obtained to establish wave modes and phase velocity curves of the wave propagation in a functionally graded plate,including the effects of changing compositional characteristics of materials.

关键词： FGM plate effects of material properties wave propagation indeterminate integral variables inverse sinus hyperbolic function

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Glucokinase regulatory protein rs780094 polymorphism is associated with type 2 diabetes mellitus, dyslipidemia, non-alcoholic fatty liver disease, and nephropathy

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World Journal of Diabetes 2024年第5期15卷 814-817页

作者： ashraf Al Madhoun Department of Genetics and Bioinformatics Dasman Diabetes InstituteDasman 15400Kuwait

In this editorial,we comment on the article by Liu et al published in the recent issue of the World Journal of Diabetes(Relationship between GCKR gene rs780094 polymorphism and type 2 diabetes with albuminuria).Type 2 diabetes mellitus(T2DM)is a chronic disorder characterized by dysregulated glucose *** persistent elevated blood glucose level in T2DM significantly increases the risk of developing severe complications,including cardiovascular disease,re-tinopathy,neuropathy,and nephropathy.T2DM arises from a complex interplay between genetic,epigenetic,and environmental *** genomic studies have identified numerous genetic variations associated with an increased risk of ***,variations within the glucokinase regulatory protein(GCKR)gene have been linked to heightened susceptibility to T2DM and its associated *** clinical trial by Liu et al further elucidates the role of the GCKR rs780094 polymorphism in T2DM and nephropathy *** findings demonstrate that individuals carrying the CT or TT genotype at the GCKR rs780094 locus are at a higher risk of developing T2DM with albuminuria compared to those with the CC *** findings highlight the importance of genetic testing and risk assessment in T2DM to develop effective preventive strategies and personalized treatment plans.

关键词： Glucokinase regulatory protein rs780094 Type 2 diabetes mellitus Dyslipidemia Non-alcoholic fatty liver disease Nephropathy

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