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Free vibration and buckling analysis of polymeric composite beams reinforced by functionally graded bamboo fbers

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Applied mathematics and mechanics(English Edition) 2024年第3期45卷 543-562页

作者： H.m.FEIZABAD m.H.YAs Department of mechanical Engineering Razi UniversityKermanshah ***Iran

Natural fibers have been extensively researched as reinforcement materials in polymers on account of their environmental and economic advantages in comparison with synthetic fibers in the recent *** fibers are renowned for their good mechanical properties,abundance,and short cycle *** beams are one of the fundamental structural components and are susceptible to mechanical loads in engineering applications,this paper performs a study on the free vibration and buckling responses of bamboo fiber reinforced composite(BFRC)beams on the elastic *** different functionally graded(FG)layouts and a uniform one are the considered distributions for unidirectional long bamboo fibers across the *** elastic properties of the composite are determined with the law of *** Hamilton’s principle,the governing equations of motion are *** generalized differential quadrature method(GDQm)is then applied to the equations to obtain the *** achieved outcomes exhibit that the natural frequency and buckling load values vary as the fiber volume fractions and distributions,elastic foundation stiffness values,and boundary conditions(BCs)and slenderness ratio of the beam ***,a comparative study is conducted between the derived analysis outcomes for BFRC and homogenous polymer beams to examine the effectiveness of bamboo fibers as reinforcement materials,demonstrating the significant enhancements in both vibration and buckling responses,with the exception of natural frequencies for cantilever beams on the Pasternak foundation with the FG-◇fiber ***,the obtained analysis results of BFRC beams are also compared with those for carbon nanotube reinforced composite(CNTRC)beams found in the literature,indicating that the buckling loads and natural frequencies of BFRC beams are lower than those of CNTRC beams.

关键词： bamboo fiber free vibration buckling analysis functionally graded(FG)beam elastic foundation generalized differential quadrature method(GDQm)

mechanical properties and in vivo biodegradability of mg-Zr-Y-Nd-La magnesium alloy produced by a combined severe plastic deformation

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Rare metals 2021年第3期40卷 651-662页

作者： A.Torkian G.Faraji m.s.pedram school of mechanical Engineering College of EngineeringUniversity of TehranTehran 11155-4563Iran Department of Veterinary surgery and Radiology Faculty of Veterinary MedicineUniversity of Tehran14199-63111Iran

Permanent implants are going to be replaced by the implementation of biodegradable magnesium-based implants in fixation of internal bone fractures because of many concerns associated with conventional ***,biodegradable magnesium-based biomaterials exhibit higher biodegradation rate and low mechanical properties which are the main *** work aims to almost overcome both disadvantageous by grain refining of a WE43 magnesium alloy containing 93.04 wt% mg,4.12 wt% Y,2.15 wt% Nd,0.43 wt% Zr,and 0.26 wt%*** this study,the consequences of combined severe plastic deformation(sPD) on the mechanical properties.m.crostructure,and in vivo degradation behavior of WE43 magnesium alloy were *** do so,WE43 magnesium alloy was chosen and processed through multipass equal channel angular pressing(ECAP) at 330℃ for up to four passes followed by an extrusion *** results showed that higher strength and hardness with minimum ductility less was obtained in the s.m.le processed via two-pass ECAP followed by *** vivo biodegradation experiments showed higher degradation rate for the unprocessed coarse-grained(CG) WE43 *** two-pass ECAP and extruded s.m.le with ultrafine-grained(UFG) structure exhibited the lowest in vivo biodegradation rate besides appropriate mechanical *** may be concluded that the WE43 magnesium alloy processed via two-pass ECAP and extrusion could be a very promising candidate for biodegradable implants from both mechanical and biocorrosion viewpoints.

关键词： Implant severe plastic deformation WE43 Grain refinement Hardness mechanical properties

Turbulent Kinetic Energy of Flow during Inhale and Exhale to Characterize the severity of Obstructive sleep Apnea Patient

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Computer modeling in Engineering & sciences 2023年第7期136卷 43-61页

作者： W.m.Faizal C.Y.Khor muhammad Nooramin Che Yaakob N.N.N.Ghazali m.Z.Zainon Norliza Binti Ibrahim Roziana mohd razi Faculty of mechanical Engineering&Technology University Malaysia PerlisPadang Besar02100Malaysia Department of mechanical Engineering Faculty of EngineeringUniversity of MalayaKuala Lumpur50603Malaysia Department of Oral&maxillofacial Clinical science Faculty of DentistryUniversity of MalayaKuala Lumpur50603Malaysia Department of Paediatric Dentistry and Orthodontics Faculty of DentistryUniversity of MalayaKuala Lumpur50603Malaysia

This paper aims to investigate and present the numerical investigation of airflow characteristics using Turbulent Kinetic Energy(TKE)to characterize the upper airway with obstructive sleep apnea(OsA)under inhale and exhale breathing *** importance of TKE under both breathing conditions is that it showan accuratemethod in expressing the severity of flow in sleep *** fluid dynamics s.m.late the upper airway’s airflow via steady-state Reynolds-averaged Navier-stokes(RANs)with k–ωshear stress transport(ssT)*** three-dimensional(3D)airway model is created based on the CT scan images of an actual patient,meshed with 1.29 million elements using materialise Interactive medical Image Control system(mImICs)and ANsYs software,*** TKE were noticed around the region after the necking(smaller cross-sectional area)during the inhale and exhale *** turbulent kinetic energy could be used as a valuablemeasure to identify the severity of *** study is expected to provide a better understanding and clear visualization of the airflow characteristics during the inhale and exhale breathing in the upper airway of patients for medical practitioners in the OsA research field.

关键词： Obstructive sleep apnea breathing disorders real patient CFD turbulent kinetic energy

EEG/ERP evidence of possible hyperexcitability in older adults with elevated beta-amyloid

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Translational Neurodegeneration 2022年第1期11卷 835-844页

作者： Hannes Devos Kathleen Gustafson Ke Liao pedram Ahmadnezhad Bradley Estes Laura E.martin Jonathan D.mahnken William m.Brooks Jeffrey m.Burns Department of Physical Therapy Rehabilitation Scienceand Athletic TrainingUniversity of Kansas Medical CenterKansas CityKS 66160USA Department of Neurology University of Kansas Medical CenterKansas CityKS 66160USA Hoglund Biomedical Imaging Center University of Kansas Medical CenterKansas CityKS 66160USA Department of Population Health University of Kansas Medical CenterKansas CityKS 66160USA Department of Biostatistics and Data science University of Kansas Medical CenterKansas CityKS 66160USA University of Kansas Alzheimer’s Disease Center University of Kansas Medical CenterKansas CityKS 66160USA.

Background: Although growing evidence links beta-amyloid (Aβ) and neuronal hyperexcitability in preclinical mouse models of Alzheimer’s disease (AD), a s.m.lar association in humans is yet to be established. The first aim of the study was to determine the association between elevated Aβ (Aβ+) and cognitive processes.m.asured by the P3 event-related potential (ERP) in cognitively normal (CN) older adults. The second aim was to compare the event- related power between CNAβ+ and CNAβ−. methods: seventeen CNAβ+ participants (age: 73 ± 5, 11 females, montreal Cognitive Asses.m.nt [moCA] score 26 ± 2) and 17 CNAβ- participants group-matched for age, sex, and mOCA completed a working memory task (n-back with n = 0, 1, 2) test while wearing a 256-channel electro-encephalography net. P3 peak amplitude and latency of the target, nontarget and task difference effect (nontarget−target), and event-related power in the delta, theta, alpha, and beta bands, extracted from Fz, Cz, and Pz, were compared between groups using linear mixed models. P3 ampli-tude of the task difference effect at Fz and event-related power in the delta band were considered main outcomes. Correlations of mean Aβ standard uptake value ratios (sUVR) using positron emission tomography with P3 amplitude and latency of the task difference effect were analyzed using Pearson Correlation Coefficient r. Results: The P3 peak amplitude of the task difference effect at Fz was lower in the CNAβ+ group (P = 0.048). s.m.-larly, power was lower in the delta band for nontargets at Fz in the CNAβ+ participants (P = 0.04). The CNAβ+ partici-pants also demonstrated higher theta and alpha power in channels at Cz and Pz, but no changes in P3 ERP. strong correlations were found between the mean Aβ sUVR and the latency of the 1-back (r = − 0.69;P = 0.003) and 2-back (r = − 0.69;P = 0.004) of the task difference effect at channel Fz in the CNAβ+ group. Conclusions: Our data suggest that the elevated amyloid in cognitively normal ol

关键词： Event-related potentials Electro-encephalography Working memory Older adults Preclinical Beta-amyloid

A novel approach to study generalized coupled cubic schrödinger-Korteweg-de Vries equations

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Journal of Ocean Engineering and science 2024年第1期9卷 13-24页

作者： Lanre Akinyemi P.Veeresha m.T.Darvishi Hadi Rezazadeh mehmet senol Udoh Akpan Department of mathematics Lafayette CollegeEastonPAUSA Department of mathematics Christ Deemed to be UniversityBengaluru 560029India Department of mathematics Razi UniversityKermanshah 67149Iran Faculty of Engineering Technology Amol University of Special Modern TechnologiesAmolIran Department of mathematics Nev¸s ehir HacıBekta¸s Veli UniversityNev¸s ehirTurkey Drexel University Department of MathematicsPhiladelphiaPAUSA

The Kortewegde Vries(KdV)equation represents the propagation of long waves in dispersive media,whereas the cubic nonlinear schrödinger(CNLs)equation depicts the dynamics of narrow-bandwidth wave packets consisting of short dispersive waves.A model that couples these two equations seems in-triguing for s.m.lating the interaction of long and short waves,which is important in many domains of applied sciences and engineering,and such a system has been investigated in recent *** work uses a modified sardar sub-equation procedure to secure the soliton-type solutions of the generalized cubic nonlinear schrödinger-Korteweg-de Vries system of *** various selections of arbitrary parameters in these solutions,the dynamic properties of s.m. acquired solutions are represented graph-ically and *** particular,the dynamics of the bright solitons,dark solitons.m.xed bright-dark solitons,W-shaped solitons.m.shaped solitons,periodic waves,and other soliton-type *** re-sults demonstrated that the proposed technique is highly efficient and effective for the aforementioned problems,as well as other nonlinear problems that may arise in the fields of mathematical physics and engineering.

关键词： CNLs equation modiﬁed sardar sub-equation method KdV equation solitons Long and short waves

Greedy nonlinear autoregression for multifidelity computer models at different scales

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能源与人工智能(英文) 2020年第1期1卷 117-130页

作者： W.Xing m.razi R.m.Kirby K.sun A.A.shah school of Energy and Power Engineering Chongqing University174 ShazhengjieShapingbaChongqing 400044China scientific Computing and Imaging Institute University of Utah72 S Central Campus DriveRoom 3750 Salt Lake CityUT 84112United States

Although the popular multi-fidelity surrogate models,stochastic collocation and nonlinear autoregression have been applied successfully to multiple benchmark problems in different areas of science and engineering,they have certain *** propose a uniform Bayesian framework that connects these two methods allowing us to combine the strengths of *** this end,we introduce Greedy-NAR,a nonlinear Bayesian autoregressive model that can handle complex between-fidelity correlations and involves a sequential construction that allows for significant improvements in performance given a limited computational *** proposed enhanced nonlinear autoregressive method is applied to three benchmark problems that are typical of energy applications,namely molecular dynamics and computational fluid *** results indicate an increase in both prediction stability and accuracy when compared to those of the standard multi-fidelity autoregression *** results also reveal the advantages over the stochastic collocation approach in terms of accuracy and computational *** speaking,the proposed enhancement provides a straightforward and easily implemented approach for boosting the accuracy and efficiency of concatenated structure multi-fidelity s.m.lation methods,e.g.,the nonlinear autoregressive model,with a negligible additional computational cost.

关键词： multi-fidelity models Autoregressive Gaussian processes Deep Gaussian processes surrogate models molecular dynamics Computational fluid dynamics

Differentiation of Wharton's jelly mesenchymal stem cells into neurons in alginate scaffold

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Neural Regeneration Research 2015年第8期10卷 1312-1316页

作者： seyed mojtaba Hosseini Attiyeh Vasaghi Newsha Nakhlparvar Reza Roshanravan Tahereh Talaei-khozani Zahra razi student Research Committee Shiraz University of Medical Sciences Cell and molecular medicine student Research Group Medical School Shiraz University of Medical Sciences stem Cell Laboratory Department of Anatomy Shiraz University of Medical Sciences Colorectal Research Center Department of Surgery Shiraz University of Medical Science Tissue Engineering Laboratory Department of Tissue Engineering School of Advanced Medical Science and Technology Shiraz University of Medical Sciences Laboratory for stem Cell Research Department of Anatomy Medical School Shiraz University of Medical Sciences Department of medical Physics Shiraz University of Medical Sciences

Alginate scaffold has been considered as an appropriate biomaterial for promoting the differentiation of embryonic stem cells toward neuronal cell lineage. We hypothesized that alginate scaffold is suitable for culturing Wharton’s jelly mesenchymal stem cells（WJmsCs） and can promote the differentiation of WJmsCs into neuron-like cells. In this study, we cultured WJmsCs in a three-dimensional scaffold fabricated by 0.25% alginate and 50 m m Ca Cl2 in the presence of neurogenic medium containing 10 μm retinoic acid and 20 ng/m L basic fibroblast growth factor. These cells were also cultured in conventional two-dimensional culture condition in the presence of neurogenic medium as controls. After 10 days, immunofluorescence staining was performed for detecting β-tubulin（marker for WJmsCs-differentiated neuron） and CD271（motor neuron marker）. β-Tubulin and CD271 expression levels were significantly greater in the WJmsCs cultured in the three-dimensional alginate scaffold than in the conventional two-dimensional culture condition. These findings suggest that three-dimensional alginate scaffold cell culture system can induce neuronal differentiation of WJmsCs effectively.

关键词： nerve regeneration Wharton’s jelly mesenchymal stem cells.m.senchymal stem cells neurons.m.tor neurons alginate 3D scaffold neural regeneration

static and free vibration analysis of four-parameter continuous grading elliptical sandwich plates

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Applied mathematics and mechanics(English Edition) 2022年第4期43卷 523-536页

作者： m.H.YAs F.AKHLAGHI s.KAmARIAN A.H.YAs Department of mechanical Engineering Razi UniversityKermanshah ***Iran Department of mechanical Engineering Ilam BranchIslamic Azad UniversityIlam ***Iran Department of mechanical Engineering Amir-Kabir University of TechnologyTehran 158754413Iran

In the present study,the static and dynamic analyses of elliptical functionally graded sandwich(FGs)plates are *** constituent materials of the sandwich plates are ceramic and metal so that the core is.m.de of pure metal,while the face sheets consist of a combination of metal and ceramic according to a four-parameter power-law *** material profiles such as classic,s.m.etric,and as.m.etric can be obtained using the applied generalized power-law distribution *** analysis is performed based on the classical laminated plate theory(CLPT)and the Ritz *** effects of four parameters in the material distribution relation as well as different geometric parameters on the deflection and natural frequencies of elliptical FGs plates are *** results of this study show that with a proper distribution of materials,the optimal static and dynamic behavior can be *** results also indicate that the generalized power-law distribution has significant effects on the natural frequencies of elliptical FGs *** example,although the frequency parameter of a plate with ceramic face sheets is.m.re than the one with metal face sheets,the use of larger amounts of ceramic does not necessarily increase the natural frequency of the structure.

关键词： elliptical plate sandwich plate four-parameter power-law distribution static analysis free vibration analysis Ritz method

Computational Analysis of Airflow in Upper Airway under Light and Heavy Breathing Conditions for a Realistic Patient Having Obstructive sleep Apnea

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Computer modeling in Engineering & sciences 2021年第8期127卷 583-604页

作者： W.m.Faizal N.N.N.Ghazali C.Y.Khor m.Z.Zainon Irfan Anjum Badruddin sarfaraz Kamangar Norliza Binti Ibrahim Roziana mohd razi Faculty of mechanical Engineering Technology University Malaysia PerlisPerlisMalaysia Department of mechanical Engineering Faculty of EngineeringUniversity of MalayaKuala Lumpur50603Malaysia Research Center for Advanced materials science King Khalid UniversityAbha61413Saudi Arabia Department of mechanical Engineering College of EngineeringKing Khalid UniversityAbha61421Saudi Arabia Department of Oral&maxillofacial Clinical science Faculty of DentistryUniversity of MalayaKuala Lumpur50603Malaysia Department of Paediatric Dentistry and Orthodontics Faculty of DentistryUniversity of MalayaKuala Lumpur50603Malaysia

Background:Obstructive sleep apnea is a sleeping disorder that has troubled a sizeable *** is an active area of research on obstructive sleep apnea that intends to better understand airflow behaviors and therefore treat patients.m.re *** paper aims to investigate the airflow characteristics of the upper airway in an obstructive sleep apnea(OsA)patient under light and heavy breathing conditions by using Turbulent Kinetic Energy(TKE),an accurate method in expressing the flow concentration mechanisms of sleeping *** is important to visualize the concentration of flow in the upper airway in order to identify the severity level of the obstruction during ***:Computational fluid dynamic(CFD)analysis was used as a solution tool to evaluate the airflow during light and heavy breathing conditions.A medical imaging technique was used to extract the 3D model from the CT scan ***,mesh generation and s.m.lation were carried out via CFD software to evaluate the light and heavy breathing characteristics related to obstructive sleep *** state Reynold’s averaged Navier-stoke(RANs)with the k-ωshear stress transport(ssT)turbulence model was *** airflow characteristics were quantified using parameters such as pressure distribution,skin friction coefficient,velocity profile,Reynolds number,turbulent Reynolds number and turbulence kinetic ***:Contour plots at different planes were used to visualize the airflow distribution as it passed through different cross-sectional areas of the *** results revealed that the presence of a smaller cross-sectional area of the airway caused an increase in airflow parameters,especially during heavy ***,turbulent airflow conditions along the airway were noticed during heavy *** severity of OsA could be measured by the turbulent kinetic energy which is able to show the behavior and concentration of mean *** study is expected to p

关键词： Human upper airway computational fluid dynamics obstructive sleep apnea turbulent kinetic energy