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A two variable refined plate theory for the bending analysis of functionally graded plates

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Acta Mechanica Sinica 2010年第6期26卷 941-949页

作者： Ismail Mechab hassen Ait atmane Abdlouahed Tounsi hichem Abdesselem Belhadj EI Abbas Adda Bedia Laboratoire des Materiaux et hydrologie Universite de Sidi Bel AbbesBP 89 Cite Ben M'hidi22000 Sidi Bel AbbesAlgerie Departement de genie civil Faculte des Sciences de l'IngenieurUniversite Hassiba Benbouali de ChlefChlefAlgerie

Bending analysis of functionally graded plates using the two variable refined plate theory is presented in this *** number of unknown functions involved is reduced to merely four,as against five in other shear deformation theories. The variationally consistent theory presented here has, in many respects,strong similarity to the classical plate theory. It does not require shear correction factors,and gives rise to such transverse shear stress variation that the transverse shear stresses vary parabolically across the thickness and satisfy shear stress free surface *** properties of the plate are assumed to be graded in the thickness direction with their distributions following a simple power-law in terms of the volume fractions of the *** equations are derived from the principle of virtual displacements, and a closed-form solution is found for a simply supported rectangular plate subjected to sinusoidal loading by using the Navier *** results obtained by the present theory are compared with available solutions,from which it can be concluded that the proposed theory is accurate and simple in analyzing the static bending behavior of functionally graded plates.

关键词： FG plates Shear deformation theory Refined plate theory higher-order theory Navier solution

Dynamic stress concentration in an infinitely long cylindrical cavity due to a point spherical source embedded within a fluid-saturated poroelastic formation of infinite extent

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Applied Mathematics and Mechanics(English Edition) 2025年第1期46卷 139-156页

作者： h.hOSSEINI O.BALILAShAKI Department of Mechanical Engineering Faculty of EngineeringGolestan University

The effects of a harmonically exciting monopole source on an infinitely long cylindrical cavity embedded entirely within a fluid-saturated poroelastic formation of infinite extent are examined theoretically. It is assumed that the source is located outside the cavity at a specified distance from the borehole axis. The magnitudes of the hoop and radial stresses beside the pore pressures exerted on the interface and inside the porous medium surrounding the borehole are calculated and discussed. Biot's poroelastic modeling along with three types of boundary conditions for the cylindrical interface including the ideal fluid, empty borehole, and rigid inclusion with a hard boundary is employed for the analysis. Utilizing a proper translational addition theorem for expressing the incident spherical wave in terms of cylindrical wave expansions, the proposed boundary conditions at the interface are satisfied. Stresses are formulated by means of wave potential functions in a three-dimensional(3D) manner. The effects of the frequency and the radial distance between the source and borehole on the induced stresses are examined for the first cylindrical modes over frequency spectra. Two permeability conditions for the interface and three types of soils for the porous formation are considered throughout the analysis. To give an overall outline of the study, a numerical example is presented. The results clearly indicate that the distance is a key parameter and has considerable effects on the induced stress values. In addition, the interface permeability condition and soil characteristics play an important role in determining the dynamic response of the borehole. Finally,the obtained results are compared with the relevant analyses existing in the literature for some limit cases, and good agreement is achieved.

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Static Analysis of Functionally Graded Sandwich Plates Using an Efficient and Simple Refined Theory

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Chinese Journal of Aeronautics 2011年第4期24卷 432-433页

作者： hadj henni ABDELAZIZ hassen Ait atmane Ismail MEChAB Lakhdar BOUMIA Abdelouahed TOUNSI Adda Bedia El ABBAS Laboratoire des Matériaux et hydrologie Université de Sidi Bel Abbes Département de Génie Civil Université Ibn Khaldoun Département de Génie Civil Faculté de Génie Civil et d'Architecture Univesité de Chlef Département de Physique Université de Sidi Bel Abbes

In this paper, a new displacement based high-order shear deformation theory is introduced for the static response of functionally graded sandwich plate. Unlike any other theory, the number of unknown functions involved is only four, as against five in case of other shear deformation theories. The theory presented is variationally consistent, has strong similarity with classical plate theory in many aspects, does not require shear correction factor, and gives rise to transverse shear stress variation such that the transverse shear stresses vary parabolically across the thickness satisfying shear stress free surface conditions. Two common types of functionally graded sandwich plates, namely, the sandwich with fimctionally graded facesheet and homogeneous core and the sandwich with homogeneous facesheet and functionally graded core, are considered. Governing equations are derived from the principle of virtual displacements. The closed-form solution of a simply supported rectangular plate subjected to sinu- soidal loading has been obtained by using the Navier method. The validity of the present theory is investigated by comparing some of the present results with those of the classical, the first-order and the other higher-order theories. It can be concluded that the proposed theory is accurate and simple in solving the static bending behavior of functionally graded sandwich plates.

关键词： functionally graded materials sandwich plates refined plate theory bending Navier solution

Neuroinflammation as a therapeutic target in huntington's disease

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Neural Regeneration Research 2025年第3期20卷 817-818页

作者： Andrea Kwakowsky Thulani h.Palpagama Center for Brain Research and Department of Anatomy and Medical Imaging Faculty of Medical and Health SciencesUniversity of AucklandAucklandNew Zealand Pharmacology and Therapeutics School of MedicineGalway Neuroscience CentreUniversity of GalwayGalwayIreland

In 1872, George huntington presented his essay “On Chorea” to the Meigs and Mason Academy of Medicine and, in doing so, detailed a disease that would later bear his name. huntington's disease(hD) is a genetic, neurodegenerative disease that manifests as the loss of motor control,cognitive impairment,and mood and psychiatric changes in paents.

关键词： huntington inflammation Medicine

Glial response in the midcingulate cortex in huntington’s disease

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Neural Regeneration Research 2025年第1期20卷 207-208页

作者： Thulani h.Palpagama Andrea Kwakowsky Center for Brain Research and Department of Anatomy and Medical Imaging Faculty of Medical and Health SciencesUniversity of AucklandAucklandNew Zealand Pharmacology and Therapeutics School of MedicineGalway Neuroscience CenterUniversity of GalwayGalwayIreland

huntington’s disease(hD)is a genetic disease characterized by the progressive degeneration of the striatum and *** can present with a variety of symptoms that can broadly be classified into motor symptoms,inclusive of choreatic movements and rigidity,mood and psychiatric symptoms,such as depression and apathy,and cognitive symptoms,such as cognitive *** causal mutation underlying hD results from an expansion of a CAG repeat sequence on the IT15 gene,resulting in the formation and accumulation of a mutant huntingtin protein.

关键词： huntington degeneration cortex

Does mesenchymal stem cell’s secretome affect spinal sensory circuits?Implication for pain therapies

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Neural Regeneration Research 2025年第1期20卷 181-183页

作者： Francesco Ferrini Esri h.Juárez Adalberto Merighi Department of Veterinary Sciences University of TurinGrugliascoTOItaly Department of Psychiatry and Neuroscience UniversitéLavalQuébec CityQCCanada

Mesenchymal stem cells(MSCs)are multipotent adult stem cells of mesodermal origin that can be isolated from various tissues,including bone marrow,tooth pulp,adipose tissue,and umbilical *** have gained significant attention in regenerative medicine due to their ability to modulate the immune system and favor tissue *** enrich the medium in which they are cultivated with a broad range of bioactive molecules,including growth factors,cytokines,chemokines,enzymes,nucleic acids,and extracellular vesicles that collectively compose the MSC *** increasing number of pre-clinical studies suggest that delivering in vivo an MSC-conditioned medium(i.e.,the medium collected from MSC cultures after at least 3 days of exposure)exerts neuroprotective and anti-inflammatory effects in a variety of neurological conditions.

关键词： protective clinical collective

Localized magnetization reversal processes in cobalt nanorods with different aspect ratios

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Nano Research 2015年第7期8卷 2231-2241页

作者： Marc Pousthomis Evangelia Anagnostopoulou Ioannis Panagiotopoulos Rym Boubekri Weiqing Fang Frederic Ott Kahina Ait atmane Jean-Yves Piquemal Lise-Marie Lacroix Guillaume Viau Universite de Toulouse LPCNO UMR 5215 INSA CNRS UPS 135 av de Rangueil 31077 Toulouse Cedex 4 France Laboratoire Leon Brillouin CEA/CNRS UMR 12 IRAMIS CEA-Saclay 91191 Gifsur Yvette France Department of Materials Science and Engineering University ofloannina Ioannina 45110 Greece Universite Paris Diderot Sorbonne Paris Cite ITODYS CNRS UMR 7086 15 rueJ.-A de Baif 75205 Paris Cedex 13 France

We present results of the synthesis of cobalt nanorods using the polyol process and the mechanism of magnetization reversal. We show that the nucleation step is significantly dependent on the nature of the ruthenium chloride used as the nucleating agent. This allows varying the diameter and aspect ratio of the cobalt nanorods independently. Co nanorods with aspect ratio, mean diameter, and mean length in the ranges ARm =3-16, Din= 7-25 nm, and Lm=30-300 nm, respectively, were produced using this method. X-ray diffraction and electron microscopy showed that a strong discrepancy between the structural coherence and morphological aspect ratio can exist because of stacking faults. The coercivity of assemblies of different nanorods was systematically measured, and the highest values were obtained for the smallest diameter and the largest structural coherence length. Micromagnetic simulations were performed to account for the dependence of the coercive field on the diameter. An important observation is that simple coherent magnetization rotation models do not apply to these magnetic nano-objects. Even for very small diameters （Dm = 5-10 nm） well below the theoretical coherent diameter Dcoh（CO）= 24 nm, we observed inhomogeneous reversal modes dominated by nucleation at the rod edges or at structural defects such as stacking faults. We conclude that, in order to produce high-coercivity materials based on nanowires, moderate aspect ratios of 5-10 are sufficient for providing a structural coherence similar to the morphological aspect ratio. Thus, the first priority should be to avoid the formation of stacking faults within the Co nanowires.

关键词： nanorod nanowire permanent magnets micromagnetic calculations shape anisoteopy

Comparative chemical sensor for detection of chromium(Ⅵ) in aqueous solution

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Optoelectronics Letters 2025年第1期21卷 21-27页

作者： Sura h.AL-REKABI A.A.ALWAhIB Electrical Technique Department Al Suwayrah Technical Institute Middle Technical University Laser and Optoelectronics Department University of Technology-Iraq

A process for purifying aqueous solutions containing heavy and toxic metals such as chromium（Cr） has been investigated. One of the extremely harmful pollutants in rivers and seawater is the heavy metal ions due to their direct impacts on human, animals and plants are hexavalent Cr（Ⅵ）. Consequently, highly sensitive sensor to detect Cr is essential. Surface plasmon resonance（SPR） technique has attracted huge research interest in detecting heavy metals specifically. In this study, three types of prism-based SPR sensor, gold（Au）/silver（Ag）, Au/polyaniline（PANI） and Au/titanium dioxide（TiO2） nanostructured films, are investigated as potential sensing material to detect the presence of Cr（Ⅵ） ions in water. The base Au layer with thickness of 48.3 nm is deposited on a glass slide for all sensors. For Au/Ag, Au/PANI nanofibers and Au/TiO2sensor films, the Cr（Ⅵ） concentration is varied from 1 ppm to 15 ppm with sensitivity of 0.270 °ppm-1, 0.082 °ppm-1and 0.039 °ppm-1, respectively. Based on these results, the Au/PANI nanofibers are the most sensitive to Cr（Ⅵ） among the tested sensing materials.

关键词： Titanium dioxide

Free vibration and transient response of double curved beams connected by intermediate straight beams

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Applied Mathematics and Mechanics(English Edition) 2025年第1期46卷 37-62页

作者： R.A.JAFARI-TALOOKOLAEI h.GhANDVAR E.JUMAEV S.KhATIR T.CUONG-LE School of Mechanical Engineering Babol Noshirvani University of Technology Department of Mechanical Engineering Faculty of Engineering New Uzbekistan University University of Business and Science Center for Engineering Application and Technology Solutions Ho Chi Minh City Open University

This paper investigates the free vibration and transient response of interconnected structures including double curved beams and intermediate straight beams,which are all constructed from functionally graded porous(FGP) materials. The strain potential and kinetic energies of each beam along with the work done by the external force are calculated. Additionally, a higher-order beam element is introduced to derive stiffness and mass matrices, along with the force vector. The curved and straight beams are discretized, and their assembled stiffness, mass matrices, and force vectors, are *** conditions at the joints are used to derive the total matrices of the entire structure. Subsequently, the natural frequencies and transient response of the system are determined. The accuracy of the mathematical model and the self-developed computer program is validated through the comparison of the obtained results with those of the existing literature and commercial software ANSYS, demonstrating excellent ***, a comprehensive study is conducted to investigate the effects of various parameters on the free vibration and transient response of the considered structure.

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