Jiachen Li^1,2, Wenlong Deng³, Shan Qing^1,2,*, Yiqin Liu⁴, Hao Zhang^1,2, Min Zheng^1,2

FDMP-Fluid Dynamics & Materials Processing, Vol.19, No.8, pp. 2181-2200, 2023, DOI:10.32604/fdmp.2023.027299

Abstract In this study, comparing multiple models of machine learning, a multiple linear regression (MLP), multilayer feed-forward artificial neural network (BP) model, and a radial-basis feed-forward artificial neural network (RBF-BP) model are selected for the optimization of the thermal properties of TiO₂/water nanofluids. In particular, the least squares support vector machine (LS-SVM) method and radial basis support vector machine (RB-SVM) method are implemented. First, curve fitting is performed by means of multiple linear regression in order to obtain bivariate correlation functions for thermal conductivity and viscosity of the nanofluid. Then the aforementioned models are used for a predictive analysis of the… More >

A. Lkouen^1,*, M. Lamrani², A. Meskini¹, A. Khabbazi³

FDMP-Fluid Dynamics & Materials Processing, Vol.19, No.8, pp. 2013-2026, 2023, DOI:10.32604/fdmp.2023.026929

Abstract Most of the energy savings in the building sector come from the choice of the materials used and their microphysical properties. In the present study, through numerical simulations a link is established between the thermal performance of composite materials and their microstructures. First, a two-phase 3D composite structure is modeled, then the RSA (Random Sequential Addition) algorithm and a finite element method (FE) are applied to evaluate the effective thermal conductivity of these composites in the steady-state. In particular, building composites based on gypsum and clay, consolidated with peanut shell additives and/or cork are considered. The numerically determined thermal conductivities… More > Graphic Abstract

Yunfeng Li^1,#, Cheng Zhao^2,#, Qianqian Lu^2,*

Journal of Renewable Materials, Vol.11, No.5, pp. 2417-2431, 2023, DOI:10.32604/jrm.2023.025443

Abstract The control of carbon emissions and energy conservation, and environmental protection are hot spots of global concern. In this paper, phase change paraffin wax is applied to porous materials for adsorption and storage, and nature’s eco-friendly materials are selected as the porous matrix to propose an eco-friendly phase change concrete using eco-friendly materials as raw materials. It was obtained that the strength of the phase change concrete utilizing environmentally friendly materials was 25.4% to 36.8% lower than that of ordinary concrete, while some of the phase change light aggregates were found to produce slip damage with the cement paste in… More >

Zhonghai Jiang¹, Qian Wang¹, Liangbing Zhou^2,*, Chun Xiao³

FDMP-Fluid Dynamics & Materials Processing, Vol.19, No.6, pp. 1693-1708, 2023, DOI:10.32604/fdmp.2023.025270

Abstract A two-layer implicit difference scheme is employed in the present study to determine the temperature distribution in an asphalt pavement. The calculation of each layer only needs four iterations to achieve convergence. Furthermore, in order to improve the calculation accuracy a swarm intelligence optimization algorithm is also exploited to inversely analyze the laws by which the thermal physical parameters of the asphalt pavement materials change with temperature. Using the basic cuckoo and the gray wolf algorithms, an adaptive hybrid optimization algorithm is obtained and used to determine the relationship between the thermal diffusivity of two types of asphalt pavement materials… More >

Enran Hou¹, Umar Nazir², Samaira Naz³, Muhammad Sohail^2,4,*, Muhammad Nadeem⁵, Jung Rye Lee⁶, Choonkil Park^7,*, Ahmed M. Galal^8,9

CMES-Computer Modeling in Engineering & Sciences, Vol.135, No.2, pp. 1393-1411, 2023, DOI:10.32604/cmes.2022.022500

Abstract In this article, the rheology of Ferro-fluid over an axisymmetric heated disc with a variable magnetic field by considering the dispersion of hybrid nanoparticles is considered. The flow is assumed to be produced by the stretching of a rotating heated disc. The contribution of variable thermophysical properties is taken to explore the momentum, mass and thermal transportation. The concept of boundary layer mechanism is engaged to reduce the complex problem into a simpler one in the form of coupled partial differential equations system. The complex coupled PDEs are converted into highly nonlinear coupled ordinary differential equations system (ODEs) and the… More >

Belén Begines, Francisca Zamora, M. Violante de Paz, Isaac Roffé, Manuel Mancera, Juan A. Galbis^*

Journal of Renewable Materials, Vol.1, No.3, pp. 212-221, 2013, DOI:10.7569/JRM.2013.634119

Abstract A batch of linear [m,n]-type sugar-based polyureas was synthesized by polyaddition reaction in solution from hexamethylene diisocyanate or 4,4’-methylene-bis(phenyl isocyanate) with the acyclic 2,3,4-tri-O-methyl-1,5- diamino-alditols having L-arabino, or xylo confi guration or the bicyclic 1,6-diamino-1,6-dideoxy-2,4:3,5-diO-methylene-D-glucitol. The polymers were obtained in good yields and fair molecular weights. All these polyureas were semicrystalline materials showing well-defi ned melting transition within the 86−171°C range, with T_g s being dependent on the aliphatic or aromatic nature of the diisocyanate used, and on the cyclic or acyclic chemical structure of the sugar moiety. They were found to be stable up to around 240°C, decomposing at… More >

Nurul Hanan Taharuddin¹, Ridhwan Jumaidin^2,*, Muhd Ridzuan Mansor¹, Fahmi Asyadi Md Yusof³, Roziela Hanim Alamjuri^4,*

Journal of Renewable Materials, Vol.11, No.1, pp. 131-145, 2023, DOI:10.32604/jrm.2022.021528

Abstract The strict environmental regulations to overcome the drawbacks of consumption and disposal of non-renewable synthetic materials have motivated this investigation. The physical, chemical, morphological, and thermal properties of Hylocereus Polyrhizus peel (HPP) powder obtained from the raw materials were examined in this study. The physical properties analyzes of Hylocereus Polyrhizus peel (HPP) powder discovered that the moisture content, density, and water holding capacity were 9.70%, 0.45 g/cm3 , and 98.60%, respectively. Meanwhile, the chemical composition analysis of Hylocereus Polyrhizus peel (HPP) powder revealed that the powder was significantly high in cellulose contents (34.35%) from other bio-peel wastes. The crystallinity index… More > Graphic Abstract

Xiaoling Qu, Xingshuo Yang, Siqi Li, Changan Tian, Zaibo Li, Zhiguang Zhao^*

Journal of Renewable Materials, Vol.10, No.12, pp. 3335-3350, 2022, DOI:10.32604/jrm.2022.020636

Abstract The associated MgO in limestone is believed to affect the volume stability of cementitious materials at room temperature, which limits the utilization of low-grade limestone. In this study, MgO was used as an alkali activator instead of partial CaO to prepare the aerated concrete under hydrothermal conditions. The expansion process was studied to evaluate the influence of the raw materials on the gas forming stability of the slurry. The pore structure (porosity, pore size and its distribution) was analyzed by the image method. The physic-mechanical properties (density, strength, thermal properties) of concrete with the addition of MgO were comprehensively investigated.… More >

Nikola Vavřínová^*, Kateřina Stejskalová, Jiří Teslík, Kateřina Kubenková, Jiří Majer

Journal of Renewable Materials, Vol.10, No.7, pp. 1859-1873, 2022, DOI:10.32604/jrm.2022.018908

Abstract This article is focused on the investigation of the mechanical and thermal properties of composite material that could be used for the production of plaster or plasterboards. This composite material is made of gypsum and reinforcing natural fibers. The article verifies whether this natural reinforcement can improve the investigated properties compared to conventional plasters and gypsum plasterboards made of pure gypsum. From this composite material, high-strength plasterboards could then be produced, which meet the higher demands of users than conventional gypsum plasterboards. For their production, natural waste materials would be used efficiently. As part of the development of new building… More >

Yong Chen¹, Yinghao Huang^1,2,*, Min Wu¹ and Shuo Wang¹

Journal of Renewable Materials, Vol.10, No.4, pp. 1153-1173, 2022, DOI:10.32604/jrm.2022.018856

Abstract Phase change materials (PCMs) can store large amounts of energy in latent heat and release it during phase changes, which could be used to improve the freeze-thaw performance of soil. The composite phase change material was prepared with paraffin as the PCM and 8% Class C fly ash (CFA) as the supporting material. Laboratory tests were conducted to reveal the influence of phase change paraffin composite Class C fly ash (CFA-PCM) on the thermal properties, volume changes and mechanical properties of expansive soil. The results show that PCM failed to establish a good improvement effect due to leakage. CFA can… More >