Alan F.N. Boss¹, Manuella G.C. Munhoz¹, Gisele Amaral-Labat², Rodrigo G.A. Lima², Leonardo I. Medeiros^2,3, Nila C.F.L. Medeiros^2,3, Beatriz C.S. Fonseca², Flavia L. Braghiroli^4,*, Guilherme F.B. Lenz e Silva¹

Journal of Renewable Materials, Vol.12, No.10, pp. 1639-1659, 2024, DOI:10.32604/jrm.2024.056004 - 23 October 2024

Abstract Radar Absorbing Materials (RAM) are a class of composites that can attenuate incident electromagnetic waves to avoid radar detection. Most carbon allotropes that have the potential to be used as RAM are either carbon nanotubes (CNTs), graphene, carbon black (CB) and ultimately, sustainable porous carbon (SPC). Here, black wattle bark waste (following tannin extraction) was used as a sustainable source to produce SPC made from biomass waste. It was characterized and used as a filler for a silicone rubber matrix to produce a flexible RAM. The electromagnetic performance of this composite was compared with composites… More >

Nure Alam Chowdhury¹, Lulu Wang^2,*, Md Shazzadul Islam³, Linxia Gu¹, Mehmet Kaya^1,*

CMES-Computer Modeling in Engineering & Sciences, Vol.138, No.2, pp. 1301-1322, 2024, DOI:10.32604/cmes.2023.030844 - 17 November 2023

Abstract This study designs a microstrip patch antenna with an inverted T-type notch in the partial ground to detect tumor cells inside the human breast. The size of the current antenna is small enough (18 mm × 21 mm × 1.6 mm) to distribute around the breast phantom. The operating frequency has been observed from 6–14 GHz with a minimum return loss of −61.18 dB and the maximum gain of current proposed antenna is 5.8 dBi which is flexible with respect to the size of antenna. After the distribution of eight antennas around the breast phantom, the return loss curves were observed in the presence and More > Graphic Abstract

Lei Liu^*, Shenao Pang, Zhuhui Luo

Journal of Renewable Materials, Vol.11, No.11, pp. 3891-3906, 2023, DOI:10.32604/jrm.2023.028192 - 31 October 2023

Abstract The recycling of carbon fibers and protection from unwanted microwave radiation are two important environmental issues that need to be addressed in modern society. Herein, branched carbon nanofibers (CNFs) were grown in-situ on recycled carbon fibers (RCFs) through the chemical vapor deposition method using nickel as catalysts and thiophene as aided-catalysts. The effect of thiophene on the growth morphology of CNFs was investigated. Correspondingly, branched CNFs-RCFs and straight CNFs-RCFs were respectively obtained in the presence and absence of thiophene. The microstructure and electromagnetic behaviour investigations have shown that the branched CNFs possess a typical multi-branched structure, More > Graphic Abstract

Jianping Deng¹, Qianqian Zhang¹, Yuling Lan¹, Lingcong Luo¹, Zimin Dai¹, Zhonghang Lin¹, Zhixin Lu¹, Jiancheng Yuan¹, Yiqi Fu¹, Lu Luo^2,*, Weigang Zhao^1,*

Journal of Renewable Materials, Vol.11, No.6, pp. 2631-2646, 2023, DOI:10.32604/jrm.2023.027163 - 27 April 2023

Abstract The development and utilization of biomass and agroforestry processing byproducts for high-value applications have been an important topic in the field of renewable materials research. Based on this, a two-step microwave hydrothermal pre-carbonization and KOH activation method was proposed to synthesize tannin-based activated carbons with a high specific surface area, hierarchical pore structure, and good electrochemical performance. The microstructure, texture properties, and physicochemical characteristics were investigated. The results show that the prepared tannin-based activated carbons presented a hierarchical pore structure (micro- and mesopores) with a specific surface area as high as 997.46 m³ g⁻¹ . The… More > Graphic Abstract

Mohd Aminudin Jamlos^1,*, Nur Amirah Othman¹, Wan Azani Mustafa², Mohd Faizal Jamlos³, Mohamad Nur Khairul Hafizi Rohani²

CMC-Computers, Materials & Continua, Vol.75, No.1, pp. 277-292, 2023, DOI:10.32604/cmc.2023.032840 - 06 February 2023

Abstract Metamaterials (MTM) can enhance the properties of microwaves and also exceed some limitations of devices used in technical practice. Note that the antenna is the element for realizing a microwave imaging (MWI) system since it is where signal transmission and absorption occur. Ultra-Wideband (UWB) antenna superstrates with MTM elements to ensure the signal transmitted from the antenna reaches the tumor and is absorbed by the same antenna. The lack of conventional head imaging techniques, for instance, Magnetic Resonance Imaging (MRI) and Computerized Tomography (CT)-scan, has been demonstrated in the paper focusing on the point of… More >

Sheng He¹, Weiqi Leng^2,*, Yuhe Chen¹, Hongchen Li³, Jingpeng Li¹, Zaixing Wu¹, Zizhang Xiao¹

Journal of Renewable Materials, Vol.11, No.1, pp. 321-331, 2023, DOI:10.32604/jrm.2023.022097 - 10 August 2022

Abstract Microwave (MW) drying method was adopted to enhance the liquid permeability of Scots pine lumber. Structure changes were characterized by stereoscope microscope, scanned electron microscope (SEM) and transmission electron microscope (TEM) examination. Pore parameters before and after MW treatment were detected by mercury intrusion porosimetry (MIP) method, and the effect of structure changes on liquid permeability were analyzed. As stereoscope microscope, SEM and TEM examination results shown, macro and micro checks mainly developed at intercellcular of tracheids, intercellular of ray parenchyma and tracheid, while these checks extend main along the radial-longitudinal plane. Pit border destruction, More >

Xiya Yu¹, Nianfeng Wei², Qisong Liu², Zhiyong Wu², Mizi Fan³, Weigang Zhao^1,*, Qinzhi Zeng^1,*

Journal of Renewable Materials, Vol.10, No.8, pp. 2041-2053, 2022, DOI:10.32604/jrm.2022.018027 - 25 April 2022

Abstract To improve the mechanical properties of fast-growing Chinese fir (Cunnighamia lanceolate), expand its range of application, increase its value, and avoid the environmental pollution caused by impregnation with synthetic resin, Chinese fir was impregnated with a shellac solution. Since the shellac solution was difficult to penetrate into fast-growing Chinese fir, so microwave pretreatment was used to irradiate the wood to improve the permeability. This study investigated the effects of four factors, including the content of moisture in the wood before it was microwaved, the chamber pressure of microwave, the time of microwaving and the vacuum impregnation… More > Graphic Abstract

N. A. Koma'rudin¹, Z. Zakaria^1,*, A. A. Althuwayb², H. Lago³, H. Alsariera¹, H. Nornikman¹, A. J. A. Al-Gburi¹, P. J. Soh^4,5

CMC-Computers, Materials & Continua, Vol.72, No.1, pp. 983-998, 2022, DOI:10.32604/cmc.2022.024782 - 24 February 2022

Abstract This work proposes a wideband and unidirectional antenna consisting of dual layer of coplanar waveguide based on the circular parasitic element technique. The design procedure is implemented in three stages: Design A, which operates at 3.94 GHz with a bandwidth of 3.83 GHz and a fractional bandwidth (FBW) of 97.2%; Design B, which operates at 3.98 GHz with a bandwidth of 0.66 GHz (FBW of 56.53%); and Design C as the final antenna. The final Design C is designed to resonate at several frequencies between 2.89 and 7.0 GHz for microwave imaging applications with a More >

Shafayat Hossain¹, Md. Iquebal Hossain Patwary¹, Sikder Sunbeam Islam¹, Sultan Mahmud^1,2, Norbahiah Binti Misran², Ali F. Almutairi³, Mohammad Tariqul Islam^2,*

CMC-Computers, Materials & Continua, Vol.71, No.3, pp. 5817-5836, 2022, DOI:10.32604/cmc.2022.022042 - 14 January 2022

Abstract This paper presents a new Double-E-Triple-H-Shaped NRI (negative refractive index) metamaterial (MM) for dual-band microwave sensing applications. Here, a horizontal H-shaped metal structure is enclosed by two face-to-face E-shaped metal structures. This double-E-H-shaped design is also encased by two vertical H-shaped structures along with some copper links. Thus, the Double-E-Triple-H-Shaped configuration is developed. Two popular substrate materials of Rogers RO 3010 and FR-4 were adopted for analyzing the characteristics of the unit cell. The proposed structure exhibits transmission resonance inside the S-band with NRI and ENG (Epsilon Negative) metamaterial properties, and inside the C-band with… More >

Kabir Hossain^1,2, Thennarasan Sabapathy^1,2,*, Muzammil Jusoh^1,2, Ping Jack Soh^1,3, Samir Salem Al-Bawri⁴, Mohamed Nasrun Osman^1,2, Hasliza A. Rahim^1,2, Danai Torrungrueng⁵, Prayoot Akkaraekthalin⁶

CMC-Computers, Materials & Continua, Vol.71, No.1, pp. 1677-1693, 2022, DOI:10.32604/cmc.2022.022227 - 03 November 2021

Abstract This paper introduces a decagonal C-shaped complementary split-ring resonator (CSRR) textile-based metamaterial (MTM). The overall size of the proposed sub-wavelength MTM unit cell is 0.28λ₀ × 0.255λ₀ at 3 GHz. Its stopband behaviour was first studied prior analysing the negative index properties of the proposed MTM. It is worth noting that in this work a unique way the experiments were completed. For both simulations and measurements, the proposed MTM exhibited negative-permittivity and negative-refractive index characteristics with an average bandwidth of more than 3 GHz (considering 1.7 to 8.2 GHz as the measurements were carried out within this range).… More >