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  • Open Access

    PROCEEDINGS

    Study on the Flow Dead Zone in the Shell of an Industrial Tubular Fixed Bed Reactor

    Binbin Hao1, Zhenming Liu1,*, Yajun Deng1,*, Dongliang Sun1, Wei Zhang1, Bo Yu1

    The International Conference on Computational & Experimental Engineering and Sciences, Vol.30, No.1, pp. 1-1, 2024, DOI:10.32604/icces.2024.012194

    Abstract The tubular fixed bed reactor is widely used in industrial production because of its strong applicability, high stability and easy maintenance. The flow dead zone in the shell of the reactor will significantly affect the overall performance of the reactor. Reducing the flow dead zone in the shell is the main way to optimize the performance of tubular fixed bed reactor. At present, most of the research on the flow dead zone of the reactor is based on the simplified reactor model, the number and size of tubes are far from the industrial requirements. In… More >

  • Open Access

    PROCEEDINGS

    Concurrent Topology Optimization of Shell Structures with Multi-Configuration and Variable-Density Infill

    Wei Ji1, Yingchun Bai1,*

    The International Conference on Computational & Experimental Engineering and Sciences, Vol.29, No.3, pp. 1-2, 2024, DOI:10.32604/icces.2024.011338

    Abstract The superior stiffness-to-weight and strength-to-weight mechanical advantages of shell-infill structures can be fully exploited through concurrent design of the entire topology and infill configuration. This inherent design freedom can be guaranteed by additive manufacturing, through which complicated geometry can be fabricated. The existing approaches are typically focused on topology optimization with porous infill [1-3], un-prescribed lattice configuration with uniform density [4-8], or prescribed single lattice configuration with non-uniform density [9-10]. Towards higher performance yet lightweight, this work proposes a concurrent topology optimization approach to directly generate shell-infill structures in which the inner infill consists of… More >

  • Open Access

    PROCEEDINGS

    Hierarchically Designed Shell-Plate Metamaterials with Excellent Isotropic Yield Strength

    Zongxin Hu1,*, Junhao Ding1, Qingping Ma1, Xu Song1

    The International Conference on Computational & Experimental Engineering and Sciences, Vol.29, No.2, pp. 1-1, 2024, DOI:10.32604/icces.2024.011288

    Abstract Hierarchically designed metamaterials can be found in numerous fields such as hard biomaterials and man-made structures. Recently, additively manufactured metamaterials are very promising in meeting the increasing demands for materials providing nearly isotropic yield strength in lightweight engineering as the controlled micro-structures. In this paper, a novel hierarchically shell-plate lattice structures are introduced by placing the plates along the closed shell-based structures. With fixed relative density of 10% for hierarchical metamaterials, the effects of different cell sizes and shell thicknesses of shell lattice structures on isotropy are studied. Based on theoretical analysis, the design map… More >

  • Open Access

    ARTICLE

    Characterization of Hydroxyapatite Extracted from Crab Shell Using the Hydrothermal Method with Varying Holding Times

    Deni Fajar Fitriyana1,2,*, Rifky Ismail1,3,*, Athanasius Priharyoto Bayuseno1, Januar Parlaungan Siregar4,5, Tezara Cionita6

    Journal of Renewable Materials, Vol.12, No.6, pp. 1145-1163, 2024, DOI:10.32604/jrm.2024.052165 - 02 August 2024

    Abstract Hydroxyapatite (HA) is a bio ceramic commonly utilized in bone tissue engineering due to its bioactive and osteoconductive properties. Crab shells are usually disregarded as waste material despite their significant CaCO content, and have not been widely utilized in the synthesis of HA. This study aims to synthesize and analyze HA derived from crab shells using the hydrothermal method with different durations of holding time. This study utilized precipitated calcium carbonate (PCC) derived from crab shells. With a hydrothermal reactor set at 160°C and varying holding times of 14 (HA_14), 16 (HA_16), and 18 (HA_18)… More > Graphic Abstract

    Characterization of Hydroxyapatite Extracted from Crab Shell Using the Hydrothermal Method with Varying Holding Times

  • Open Access

    ARTICLE

    Simple and High-Yield Synthesis of a Thinner Layer of Graphenic Carbon from Coconut Shells

    Retno Asih1,*, Haniffudin Nurdiansah2, Mochamad Zainuri1, Deni S. Khaerudini3,4, Angelinus T. Setiawan4, A. Y. Dias4, Pudji Untoro4,5, Ahmad Sholih1, Darminto1,*

    Journal of Renewable Materials, Vol.12, No.5, pp. 969-979, 2024, DOI:10.32604/jrm.2024.049097 - 17 July 2024

    Abstract Biomass has become of recent interest as a raw material for ‘green’ graphenic carbon (GC) since it promotes an environmentally friendly approach. Here, we investigate a single pyrolysis route to synthesize GC from coconut shells which provides a simple method and can produce a high yield, thus being convenient for large-scale production. The pyrolysis involves a stepped holding process at 350°C for 1 h and at 650°C or 900°C for 3 h. The GC sample resulted at the 900°C pyrolysis has a thinner sheet, a less porous structure, a higher C/O ratio, and an enhanced More > Graphic Abstract

    Simple and High-Yield Synthesis of a Thinner Layer of Graphenic Carbon from Coconut Shells

  • Open Access

    ARTICLE

    Performance Analysis of Plant Shells/PVC Composites under Corrosion and Aging Conditions

    Haoping Yao1, Xinyu Zhong2, Chunxia He1,*

    Journal of Renewable Materials, Vol.12, No.5, pp. 993-1006, 2024, DOI:10.32604/jrm.2024.047758 - 17 July 2024

    Abstract To make full use of plant shell fibers (rice husk, walnut shell, chestnut shell), three kinds of wood-plastic composites of plant shell fibers and polyvinyl chloride (PVC) were prepared. X-ray diffraction analysis was carried out on three kinds of plant shell fibers to test their crystallinity. The aging process of the composites was conducted under 2 different conditions. One was artificial seawater immersion and xenon lamp irradiation, and the other one was deionized water spray and xenon lamp irradiation. The mechanical properties (tensile strength, flexural strength, impact strength), changes in color, water absorption, Fourier transform… More >

  • Open Access

    ARTICLE

    Fabrication of Core-Shell Hydrogel Bead Based on Sodium Alginate and Chitosan for Methylene Blue Adsorption

    Xiaoyu Chen*

    Journal of Renewable Materials, Vol.12, No.4, pp. 815-826, 2024, DOI:10.32604/jrm.2024.048470 - 12 June 2024

    Abstract A novel core-shell hydrogel bead was fabricated for effective removal of methylene blue dye from aqueous solutions. The core, made of sodium alginate-g-polyacrylamide and attapulgite nanofibers, was cross-linked by Calcium ions (Ca). The shell, composed of a chitosan/activated carbon mixture, was then coated onto the core. Fourier transform infrared spectroscopy confirmed the grafting polymerization of acrylamide onto sodium alginate. Scanning electron microscopy images showed the core-shell structure. The core exhibited a high water uptake ratio, facilitating the diffusion of methylene blue into the core. During the diffusion process, the methylene blue was first adsorbed by More > Graphic Abstract

    Fabrication of Core-Shell Hydrogel Bead Based on Sodium Alginate and Chitosan for Methylene Blue Adsorption

  • Open Access

    ARTICLE

    Full-Scale Isogeometric Topology Optimization of Cellular Structures Based on Kirchhoff–Love Shells

    Mingzhe Huang, Mi Xiao*, Liang Gao, Mian Zhou, Wei Sha, Jinhao Zhang

    CMES-Computer Modeling in Engineering & Sciences, Vol.139, No.3, pp. 2479-2505, 2024, DOI:10.32604/cmes.2023.045735 - 11 March 2024

    Abstract Cellular thin-shell structures are widely applied in ultralightweight designs due to their high bearing capacity and strength-to-weight ratio. In this paper, a full-scale isogeometric topology optimization (ITO) method based on Kirchhoff–Love shells for designing cellular tshin-shell structures with excellent damage tolerance ability is proposed. This method utilizes high-order continuous nonuniform rational B-splines (NURBS) as basis functions for Kirchhoff–Love shell elements. The geometric and analysis models of thin shells are unified by isogeometric analysis (IGA) to avoid geometric approximation error and improve computational accuracy. The topological configurations of thin-shell structures are described by constructing the effective More >

  • Open Access

    ARTICLE

    Effect of Adhesive Type on the Quality of Coconut Shell Charcoal Briquettes Prepared by the Screw Extruder Machine

    Samsudin Anis1,*, Deni Fajar Fitriyana1, Aldias Bahatmaka1, Muhammad Choirul Anwar1, Arsyad Zanadin Ramadhan1, Fajar Chairul Anam1, Raffanel Adi Permana1, Ahmad Jazilussurur Hakim2, Natalino Fonseca Da Silva Guterres3, Mateus De Sousa Da Silva3

    Journal of Renewable Materials, Vol.12, No.2, pp. 381-396, 2024, DOI:10.32604/jrm.2023.047128 - 11 March 2024

    Abstract Indonesia is one of the largest coconut-producing countries in the world. The utilization of coconut shell waste into briquettes will increase the selling value and become a great export opportunity. However, the effect of adhesives on the quality of coconut shell charcoal briquettes made using screw extruder machine has not been widely studied. This study aims to determine the effect of adhesive type on the quality of coconut shell charcoal briquettes. The process of fabricating briquettes in this study included crushing, mixing, blending, pressing, and drying. In the mixing process, 3 types of adhesives were… More > Graphic Abstract

    Effect of Adhesive Type on the Quality of Coconut Shell Charcoal Briquettes Prepared by the Screw Extruder Machine

  • Open Access

    ARTICLE

    CFD-Based Optimization of a Shell-and-Tube Heat Exchanger

    Juanjuan Wang*, Jiangping Nan, Yanan Wang

    FDMP-Fluid Dynamics & Materials Processing, Vol.19, No.11, pp. 2761-2775, 2023, DOI:10.32604/fdmp.2023.021175 - 18 September 2023

    Abstract The main objective of this study is the technical optimization of a Shell-and-Tube Heat Exchanger (STHE). In order to do so, a simulation model is introduced that takes into account the related gas-phase circulation. Then, simulation verification experiments are designed in order to validate the model. The results show that the temperature field undergoes strong variations in time when an inlet wind speed of 6 m/s is considered, while the heat transfer error reaches a minimum of 5.1%. For an inlet velocity of 9 m/s, the heat transfer drops to the lowest point, while the More >

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