Guojun Zheng^1,2, Zhaomin Yan¹, Yang Xia^1,2, Ping Hu^1,2, Guozhe Shen^1,2,*

CMES-Computer Modeling in Engineering & Sciences, Vol.134, No.3, pp. 1975-1995, 2023, DOI:10.32604/cmes.2022.021415

Abstract Peridynamics (PD) is a non-local mechanics theory that overcomes the limitations of classical continuum mechanics (CCM) in predicting the initiation and propagation of cracks. However, the calculation efficiency of PD models is generally lower than that of the traditional finite element method (FEM). Structural idealization can greatly improve the calculation efficiency of PD models for complex structures. This study presents a PD shell model based on the micro-beam bond via the homogenization assumption. First, the deformations of each endpoint of the micro-beam bond are calculated through the interpolation method. Second, the micro-potential energy of the axial, torsional, and bending deformations… More >

Dan Zhao^1,*, Qiong Wu¹, Minyao Gan², Ke Li¹, Wenhong Ma¹, Qun Wu¹, Liqiang Dong¹, Shaogang Liu¹

CMES-Computer Modeling in Engineering & Sciences, Vol.134, No.3, pp. 2041-2055, 2023, DOI:10.32604/cmes.2022.021026

Abstract To reduce the vibration and sound radiation of underwater cylindrical shells, a skin composed of micro floating raft arrays and a compliant wall is proposed in this paper. A vibroacoustic coupling model of a finite cylindrical shell covered with this skin for the case of turbulence excitation is established based on the shell theories of Donnell. The model is solved with the modal superposition method to investigate the effects of the structural parameters of micro floating raft elements on the performance of reducing vibration and sound radiation of the cylindrical shell of this skin. The results indicate that increasing the… More >

Miguel Ángel Ramírez¹, Luis Alfonso^†, Patricia González², Juan Reinerio Fagundo², Margaret Suarez³, Clara Melian³, Tania Rodríguez¹, Carlos Peniche^4,*

Journal of Renewable Materials, Vol.3, No.1, pp. 73-80, 2015, DOI:10.7569/JRM.2014.634116

Abstract The demineralization kinetics of deproteinized lobster shells using CO₂ were studied. Demineralization reaction proceeds until the concentration of Ca⁺² in solution reaches an equilibrium value. The introduction of a cation exchange resin (cationite), in an open system for CO₂ , allows replacement of the solution Ca²⁺ ions by Na⁺ ions, whereby the equilibrium shifts and an effective dissolution of the exoskeletons’ calcite is achieved. The mathematical relationships between the conductivity of the solution and the concentrations of major ions, the rate constants and kinetic parameters of the reaction in the absence and presence of the resin were obtained. It was… More >

Kesheng Lin^1,2, Jiawen Zhou^1,2, Lijuan Han^1,2, Ning Li^1,2,*

Phyton-International Journal of Experimental Botany, Vol.92, No.1, pp. 285-296, 2023, DOI:10.32604/phyton.2022.023219

Abstract As a traditional herbal medicine, the major alkaloids in Uncaria rhynchophylla have been proven to have blood pressure-lowering and sedative effects. It is essential to develop an effective method for the determination of the major alkaloids in U. rhynchophylla. In this research, a rapid quantitative analysis involving multi-components analysis by a single marker strategy coupled with core-shell column HPLC was adopted to analyse four alkaloids (corynoxeine, isocorynoxeine, isorhynchophylline, rhynchophylline) in U. rhynchophylla. Isorhynchophylline was selected as the internal reference substance, the content of which was determined by the traditional external standard method. Relative correction factors (RCF) between isorhynchophylline and the… More >

Francesco Tornabene^*, Matteo Viscoti, Rossana Dimitri

CMES-Computer Modeling in Engineering & Sciences, Vol.134, No.2, pp. 1393-1468, 2023, DOI:10.32604/cmes.2022.022237

Abstract In the present manuscript, a Layer-Wise (LW) generalized model is proposed for the linear static analysis of doublycurved shells constrained with general boundary conditions under the influence of concentrated and surface loads. The unknown field variable is modelled employing polynomials of various orders, each of them defined within each layer of the structure. As a particular case of the LW model, an Equivalent Single Layer (ESL) formulation is derived too. Different approaches are outlined for the assessment of external forces, as well as for non-conventional constraints. The doubly-curved shell is composed by superimposed generally anisotropic laminae, each of them characterized… More >

Lei Guo^1,2,3, Zekun Wang¹, Lixia Guo^1,2,3,*, Pingping Chen¹

Journal of Renewable Materials, Vol.11, No.1, pp. 453-471, 2023, DOI:10.32604/jrm.2023.023315

Abstract Taking an industrial sludge and its preparation of sludge wrap shell aggregates (WSAs) instead of sand to prepare baking-free brick as the research object, the development law of mechanical properties and the influence mechanism of macro and micro characteristic parameters of the bricks under different sludge and WSAs replacement rates were studied through the macroscopic mechanical properties test, with the help of nuclear magnetic resonance (NMR), transmission electron microscopy-energy spectrum and other testing technology and pores and cracks analysis system (PCAS) software. The results showed that the compressive strength of each sample decreased with the increase of sludge content. When… More > Graphic Abstract

Yueqiang Yu¹, Tingang Ma¹, Suling Wang^1,*, Minzheng Jiang¹, Yanling Guo^2,3, Ting Jiang^1,*, Shuaiqi Huang¹, Ziming Zheng¹, Bo Yan¹, Jiyuan Lv¹

Journal of Renewable Materials, Vol.11, No.1, pp. 333-347, 2023, DOI:10.32604/jrm.2022.022296

Abstract A calculation model of stress field in laser additive manufacturing of walnut shell composite powder (walnut shell/Co-PES powder) was established. The DFLUX subroutine was used to implement the moveable application of a double ellipsoid heat source by considering the mechanical properties varying with temperature. The stress field was simulated by the sequential coupling method, and the experimental results were in good accordance with the simulation results. In addition, the distribution and variation of stress and strain field were obtained in the process of laser additive manufacturing of walnut shell composite powder. The displacement of laser additive manufacturing walnut shell composite… More > Graphic Abstract

Francesco Tornabene^*, Matteo Viscoti, Rossana Dimitri

CMES-Computer Modeling in Engineering & Sciences, Vol.133, No.3, pp. 719-798, 2022, DOI:10.32604/cmes.2022.022210

Abstract The article proposes an Equivalent Single Layer (ESL) formulation for the linear static analysis of arbitrarily-shaped shell structures subjected to general surface loads and boundary conditions. A parametrization of the physical domain is provided by employing a set of curvilinear principal coordinates. The generalized blending methodology accounts for a distortion of the structure so that disparate geometries can be considered. Each layer of the stacking sequence has an arbitrary orientation and is modelled as a generally anisotropic continuum. In addition, re-entrant auxetic three-dimensional honeycomb cells with soft-core behaviour are considered in the model. The unknown variables are described employing a… More > Graphic Abstract

Nora Elizondo-Villarreal^1,*, Luz H. Verástegui-Dominguez¹, Jose J. Quijano-Briones¹, Francisco J. Vázquez-Rodríguez², Eden Rodríguez-Castellanos³, Enrique López-Cuellar³, Ernesto Torres-Lopez¹, Victor M. Castaño-Meneses^4,*

Journal of Renewable Materials, Vol.10, No.12, pp. 3559-3572, 2022, DOI:10.32604/jrm.2022.021945

Abstract

Agave salmiana ash and poultry eggshell powder as CaO sources were used for obtaining nanostructured hydroxyapatite (HAP). The synthesis was carried out by the Green Chemistry Hydrothermal Biosynthesis at 180°C with a pH of 5, by reacting CaO from Agave Salmiana ash and Eggshell powder, with dibasic calcium phosphate (CaHPO₄•2H₂O) in an aqueous solution, with Aloe barbadensis extract. The product was characterized by X-ray diffraction, Fourier-transform infrared spectroscopy (FT-IR), Scanning Electron Microscopy (SEM), and Transmission Electron Microscopy (TEM). The size and shape of the hydroxyapatite particles changed dramatically in the presence of Aloe barbadensis. Large crystals of Hydroxyapatite were observed… More > Graphic Abstract

Zhiguang Yang^1,*, Gaojun Yan^1,2, Xueping Liu¹, Zhengyuan Feng¹, Xinfeng Zhu¹, Yanli Mao¹, Songtao Chen¹, Zhisheng Yu², Ruimei Fan³, Linlin Shan^3,*

Journal of Renewable Materials, Vol.10, No.12, pp. 3573-3585, 2022, DOI:10.32604/jrm.2022.022031

Abstract Adsorption can be used to recover effectively the volatile organic gases (VOCs) in the exhaust gas from factories through using an appropriate adsorption bed. Due to form a physical or chemical bond, adsorption occurs between the porous solid medium and the liquid or gas multi-component fluid mixture. The regeneration capacity of the adsorbent is as important as the adsorption capacity and it determines the economics of the adsorption system. The regeneration of adsorbent can be realized through changing the pressure or temperature of the system. Here, activated carbon samples from coconut shell were prepared and characterized. Benzene or formaldehyde in… More > Graphic Abstract