Mushtaq Ahmad Khan^1,*, Ahmed B. Altamimi², Zawar Hussain Khan³, Khurram Shehzad Khattak³, Sahib Khan^4,*, Asmat Ullah³, Murtaza Ali¹

CMES-Computer Modeling in Engineering & Sciences, Vol.126, No.1, pp. 55-88, 2021, DOI:10.32604/cmes.2021.011163 - 22 December 2020

Abstract This article introduces a fast meshless algorithm for the numerical solution nonlinear partial differential equations (PDE) by Radial Basis Functions (RBFs) approximation connected with the Total Variation (TV)-based minimization functional and to show its application to image denoising containing multiplicative noise. These capabilities used within the proposed algorithm have not only the quality of image denoising, edge preservation but also the property of minimization of staircase effect which results in blocky effects in the images. It is worth mentioning that the recommended method can be easily employed for nonlinear problems due to the lack of More >

Ilyas Renreng¹, Bakri Bakri^2,*, Sri Chandrabakty², Naharuddin²

Journal of Renewable Materials, Vol.9, No.2, pp. 325-335, 2021, DOI:10.32604/jrm.2021.012774 - 15 December 2020

Abstract In this study, the influence of sodium hydroxide (NaOH) treatment and microwave treatment of coir fibers on the mechanical and physical properties of pressed coir fiber/epoxy composite were evaluated. The composite was fabricated with a hand lay-up method with compression molding. Before composite fabrication, pressed coir fiber was treated with NaOH and microwave treatments. Mechanical testing (tensile, flexural, and impact testing) of the composite was conducted. Then, water absorption and thickness swelling testing are also performed. The fractured composite surface morphology after the tensile test was analyzed by scanning electronic microscopy (SEM). The results revealed… More >

Lu Hong¹, Biqing Shu^1,2, Qian He¹, Zehui Ju¹, Haiyang Zhang¹, Xiaoning Lu^1,*

Journal of Renewable Materials, Vol.9, No.1, pp. 49-59, 2021, DOI:10.32604/jrm.2021.013833 - 30 November 2020

Abstract Chinese fir was compressed by vacuum hot pressing and conventional hot pressing at different temperatures (180°C, 200°C and 220°C), respectively. The color parameters of the heat-compressed sample were measured, the relative mechanical properties of the material were tested and changes in the chemistry of fir were investigated using Fourier transform infrared spectroscopy (FTIR) and Xray photoelectron spectroscopy (XPS). The results indicated that the color difference between compressed and untreated wood increased gradually with the increase of temperature. Compared with the conventional hot pressing treatment, the color difference (ΔE*) of the Chinese fir treated by vacuum More >

A. Bikoro Bi Athomo^1,2, S. P. Engozogho Anris^1,2, R. Safou Tchiama^2,3, F. Eyma⁴, C. Arnaudguilhem⁵, B. Charrier^1,*

Journal of Renewable Materials, Vol.9, No.1, pp. 35-48, 2021, DOI:10.32604/jrm.2021.013626 - 30 November 2020

Abstract

A complementary approach using Liquid Chromatographic-Mass Spectrometric analysis was proposed to characterize phenolic compounds from the methanol-water extracts of K. ivorensis A. Chev. Two High Performance Liquid Chromatography (HPLC) complementary methods were used for the determination of phenolic compounds from the bark, sapwood and heartwood of K. ivorensis. Methods employed involved direct analysis after filtration at 0.20 µm, using a RP C₁₈ column and UV-VIS/ESI-FTMS detection. The methods used were different by their elution gradient and allowed analyzing the chemical composition of three parts of African mahogany extracts. In this study, 22 phenolic compounds and derivatives from K. ivorensis

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Christ Stone Arnaud Bopenga Bopenga¹, Henri Meyo Degboevi¹, Kevin Candelier², Prosper Edou Engonga³, Stéphane Dumarçay¹, Marie France Thévenon², Christine Gérardin Charbonnier¹, Philippe Gérardin^1,*

Journal of Renewable Materials, Vol.9, No.1, pp. 17-33, 2021, DOI:10.32604/jrm.2021.013366 - 30 November 2020

Abstract

Chemical composition of the bark extracts of Coula edulis was investigated to find potential antioxidant, anti-termite and antifungal compounds which can find useful applications in the fields of food, nutraceuticals, cosmetics or agrochemical. Phytochemical screening revealed the presence of several groups of active molecules such as alkaloids, polyphenols, flavonoids, saponins and sterols and/or terpenes in the different extracts. Total phenols, condensed tannins and flavonoids contents corroborated phytochemical screening. Gas chromatography-mass spectrometry (GC-MS) analysis revealed compounds in dichloromethane extract different from those obtained with all the other solvents. Hexadecanoic and trans-9-octadecenoic acids, as well as stigmasterol and β-sitosterol

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Febrina Dellarose Boer^1,2,3, Jérémy Valette^1,2, Jean-Michel Commandré^1,2, Mériem Fournier^3,4, Marie-France Thévenon^1,2,*

Journal of Renewable Materials, Vol.9, No.1, pp. 97-117, 2021, DOI:10.32604/jrm.2021.013147 - 30 November 2020

Abstract Sugarcane bagasse was pyrolyzed using a laboratory fixed bed reactor to produce char and its by-product (pyrolysis liquid). The pyrolysis experiments were carried out using different temperatures (400°C and 500°C), heating rate (1 °C/min and 10 °C/min), and holding time (30 min and 60 min). Char was characterized according to its thermal properties, while the pyrolysis liquid was tested for its anti-fungal and anti-termite activities. Pyrolysis temperature and heating rate had a significant influence on the char properties and the yield of char and pyrolysis liquid, where a high-quality char and high yield of pyrolysis… More >

Dexby de Guzman, Rizalinda de Leon^*

Journal of Renewable Materials, Vol.9, No.1, pp. 145-162, 2021, DOI:10.32604/jrm.2021.011646 - 30 November 2020

Abstract Levulinic acid (LA) is a platform biorefinery chemical from biomass which can be converted to green solvents, plasticizers, polymer precursors, bio-based cleaning agents, fuels and fuel additives. This study assessed the potential of SnCl₂-based mixed acid systems as catalyst in the hydrothermal conversion of microcrystalline cellulose to levulinic acid. Maximum LA yield of 36.2 mol% was achieved using 0.2 M SnCl₂ concentration at test conditions of 3 h, 180°C and 1% w/v cellulose loading. To reduce precipitate formation and further improve LA yield, the strategy employed was to combine SnCl₂ (a Lewis acid) with conventional mineral acids… More >

Ting Jiang^1,3, Chunmei Yang^1,2,*, Yueqiang Yu³, Bakary S. Doumbia^1,2, Jiuqing Liu^1,*, Yan Ma^1,2

Journal of Renewable Materials, Vol.9, No.1, pp. 119-128, 2021, DOI:10.32604/jrm.2021.011490 - 30 November 2020

Abstract

As a natural and environmentally friendly renewable material, Northeast China ash wood (NCAW) (Fraxinus mandshurica Rupr.) was cut by water-jet assisted CO₂ laser (WACL), the surface quality was evaluated by surface roughness of cut section. The surface roughness was measured by three-dimensional (3D) profilometry. Furthermore, the micromorphology of machined surface was observed by scanning electronic microscopy (SEM). Carbon content changes of machined surface were measured by energy dispersive spectrometer (EDS). A relationship between surface roughness and cutting parameters was established using response surface methodology (RSM). It is concluded that the cutting speed, laser power and water pressure

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Tabrej Khan¹, Mohamed Thariq Hameed Sultan^1,2,3,*, Mohammad Jawaid², Syafiqah Nur Azrie Safri², Ain Umaira Md Shah², Mohd Shukry Abdul Majid^4,5,*, Nik Noriman Zulkepli⁶, Haliza Jaya⁶

Journal of Renewable Materials, Vol.9, No.1, pp. 73-84, 2021, DOI:10.32604/jrm.2021.011385 - 30 November 2020

Abstract This research focused on the dynamic mechanical and thermal properties of woven mat jute/kenaf/jute (J/K/J) and kenaf/jute/kenaf (K/J/K) hybrid composites. Dynamic mechanical analysis (DMA) and Thermo-gravimetric Analysis (TGA) were used to study the effect of layering sequence on the thermal properties of kenaf/jute hybrid composites. The DMA results; it was found that the differences in the stacking sequence between the kenaf/jute composites do not affect their storage modulus, loss modulus and damping factor. From the TGA and DMA results, it has been shown that stacking sequence has given positive effect to the kenaf/jute hybrid composite… More >

Xuting Duan^1,2, Yuanhao Zhao^1,2, Kunxian Zheng^1,2,*, Daxin Tian^1,2, Jianshan Zhou^1,2,3, Jian Gao⁴

CMC-Computers, Materials & Continua, Vol.66, No.2, pp. 2127-2140, 2021, DOI:10.32604/cmc.2020.014484 - 26 November 2020

Abstract Dynamic channel assignment (DCA) is significant for extending vehicular ad hoc network (VANET) capacity and mitigating congestion. However, the un-known global state information and the lack of centralized control make channel assignment performances a challenging task in a distributed vehicular direct communication scenario. In our preliminary field test for communication under V2X scenario, we find that the existing DCA technology cannot fully meet the communication performance requirements of VANET. In order to improve the communication performance, we firstly demonstrate the feasibility and potential of reinforcement learning (RL) method in joint channel selection decision and access fallback More >