Firas Aziz Ali^a,*, Adnan M. Alsaffawi^b , Karam Hashim Mohammed^a

Frontiers in Heat and Mass Transfer, Vol.15, pp. 1-7, 2020, DOI:10.5098/hmt.15.21

Abstract The augmentation of the heat transfer in heat exchangers is one of the methods to increase efficiency of the system. The double tube heat exchanger is selected to many suitable techniques of heat transfer enhancement. In this study; the friction factor and heat transfer coefficient of double tube is evaluated experimentally. The Al₂O₃ nanoparticles dispersed in ethylene glycol (EG) with a diameter 50 nm and the weight concentration (0.1%, 0.3%, 0.5%, 0.7%, 1%) has been utilized. Then the effect of parallel current and counter current with different ranges of Reynolds number (10,000 to 30,000) on the friction factor and heat… More >

S. Ravi Teja^a , Chellapilla V. K. N. S. N. Moorthy^b,*, S. Jayakumar^c , Ayyagari Kiran Kumar^d , V. Srinivas^c,*

Frontiers in Heat and Mass Transfer, Vol.15, pp. 1-9, 2020, DOI:10.5098/hmt.15.7

Abstract This article is a summary of research involving the evaluation of the thermo-physical properties of Mono-ethylene - glycol-based solar thermic fluids oxidized multiwalled carbon nanotubes. Nanofluids were prepared with Mono-ethylene glycol and water as base fluids in 100:0, 90:10 and 80:20 ratios. These base fluids of three categories were dispersed with purified and oxidized multiwalled carbon nanotubes (MWCNTs) in the weight fractions of 0.125, 0.25 and 0.5 percentages. The variation in zeta potential is studied to examine the dispersion stability during 2 months. Thermal conductivity and dynamic viscosity were measured by hot disk method and Anton paar viscometer respectively. Significant… More >

Xintong Chen, Pinghua Zhu^*, Xiancui Yan, Lei Yang, Huayu Wang

Journal of Renewable Materials, Vol.11, No.6, pp. 2953-2967, 2023, DOI:10.32604/jrm.2023.027140

Abstract With the emphasis on environmental issues, the recycling of waste concrete, even recycled concrete, has become a hot spot in the field of architecture. But the repeated recycling of waste concrete used in harsh environments is still a complex problem. This paper discusses the durability and recyclability of recycled aggregate concrete (RAC) as a prefabricated material in the harsh environment, the effect of high-temperature curing (60°C, 80°C, and 100°C) on the frost resistance of RAC and physical properties of the second generation recycled coarse aggregate (RCA₂) of RAC after 300 freeze-thaw cycles were studied. The frost resistance of RAC was… More >

Zisheng Yang¹, Wendong Li¹, Xuelei Cheng^1,2,*, Ran Hai¹, Shunqun Li³

FDMP-Fluid Dynamics & Materials Processing, Vol.19, No.8, pp. 2119-2130, 2023, DOI:10.32604/fdmp.2023.025444

Abstract Sixteen groups of comprehensive tests have been conducted to investigate the modifications in the physical properties of a weak expansive soil due to the addition of a cement jute fiber. The tests have been conducted to analyze the liquid plastic limit, the particle distribution and the free expansion rate. The results show that: (1) With an increase in the cement-jute fiber content, the free expansion rate of the modified expansive soil gradually decreases, however, such a rate rebounds when the fiber content exceeds 0.5% and the cement content exceeds 6%. (2) With an increase in the cement percentage, the particle… More >

Sen Zhang¹, Jie Jiang^2,3,*, Yuedong Wang⁴

FDMP-Fluid Dynamics & Materials Processing, Vol.19, No.5, pp. 1159-1172, 2023, DOI:10.32604/fdmp.2022.024070

Abstract To improve the application of discrete element models (DEM) to the design of agricultural crushers, in this study a new highly accurate model is elaborated. The model takes into account the fiber structure, porous nature of the material and the leaf sheath coating structure. Dedicated experimental tests are conducted to determine the required “intrinsic” and basic contact parameters of the considered banana straw materials. A large number of bonding parameters are examined in relation to the particle aggregation model in order to characterize different actual banana straws. Using the particle surface energy contact model, the viscosity characteristics of the crushed… More > Graphic Abstract

Toufik Sahabi^1,*, Smain Balaska²

FDMP-Fluid Dynamics & Materials Processing, Vol.19, No.4, pp. 977-990, 2023, DOI:10.32604/fdmp.2022.022059

Abstract The heat transfer equation is used to determine the heat flow by conduction through a composite material along the real axis. An analytical dimensionless analysis is implemented in the framework of a separation of variables method (SVM). This approach leads to an Eigenvalues problem that is solved by the Newton’s method. Two types of dynamics are found: An unsteady condition (in the form of jumps or drops in temperatures depending on the considered case), and a permanent equilibrium (tending to the ambient temperature). The validity and effectiveness of the proposed approach for any number of adjacent layers is also discussed.… More > Graphic Abstract

Dalong Liao, Dongxu Li^*, Shun Zhou, Xiaotao Zhang, Ying Fang^*

Journal of Renewable Materials, Vol.11, No.2, pp. 625-641, 2023, DOI:10.32604/jrm.2022.022501

Abstract Graphene oxide (GO) as a new nano-enhancer in cement-based materials has gained wide attention. However, GO is easy to aggregate in alkaline cement mortar with poor dispersibility. This hinders its application in practical infrastructure construction. In this work, GO-M18 polycarboxylate compound superplasticizer (GM) were obtained by compounding the M18 polycarboxylate superplasticizer with GO solution at different mass ratios. The dispersion of GM in alkaline solution was systematically studied. The phases and functional groups of GM were characterized by XRD and FTIR. The effects of GM on the cement mortar hydration and the formation of microstructure were investigated by measuring the… More > Graphic Abstract

Shams B. Ali¹, Sarmad Fawzi Hamza Alhasan¹, Evan T. Salim^2,*, Forat H. Alsultany³, Omar S. Dahham^4,5

Journal of Renewable Materials, Vol.10, No.11, pp. 2819-2834, 2022, DOI:10.32604/jrm.2022.021609

Abstract The pulsed laser deposition (PLD) technology was used to effectively create conductive nano and micro hafnium oxide with great purity and transparency for (HfO₂) nanofilms. In many optoelectronics devices and their applications, the presence of a high dielectric substance like a nano HfO₂, between the metal contacts and the substrates was critical. We used the Pulsed Laser Deposition method to fabricate an Al/HfO₂/p-Si Schottky barrier diode where the nanostructured HfO₂ films as an intermediate layer and varied substrate temperatures. The optical result reveals a high degree of transparency (93%). The optical bandgap of deposited HfO₂ films was observed to vary… More >

Xiaoyan Liu^1,*, Li Liu¹, Junqing Zuo², Pingzhong Zhao¹, Xian Xie¹, Shijie Li¹, Kai Lyu^3,*, Chunying Wu⁴, Surendra P. Shah⁵

Journal of Renewable Materials, Vol.10, No.10, pp. 2685-2698, 2022, DOI:10.32604/jrm.2022.019527

Abstract Due to the existence of the attached mortar, the performance of the recycled concrete aggregate (RCA) is inferior to the natural aggregate, which significantly limits its wide application in industry. In this study, five kinds of modified solutions were used to modify the surface of RCA, and the modification effects were compared. The results showed that sodium silicate, nano-silica (NS), Bacillus pasteurii and soybean powder had relatively good modification effects on RCA, which could reduce the crushing value and water absorption, and increase apparent density. The composite solution (15% sodium silicate and 2% NS) and soybean powder solution had better… More >

Ibrahima Diaw^1,2,*, Mactar Faye^1,2, Seckou Bodian², Vincent Sambou²

FDMP-Fluid Dynamics & Materials Processing, Vol.18, No.5, pp. 1409-1418, 2022, DOI:10.32604/fdmp.2022.021968

Abstract Plant-based concretes are produced from plant aggregates and a binder. Plant fibers are mainly composed of saccharides (sugars) and these sugars can decrease the concentration of Ca²⁺ ions in the cement pore solution and delay the formation of hydration products. To improve the interfacial bond between fibers and matrix a chemical treatment is widely used. This study investigates the effect of sodium hydroxide treatment on physical and hygroscopic properties of Typha aggregates. In particular, a 5% sodium hydroxide solution is used to treat these aggregates and their bulk and absolute densities, porosity, water content and water absorption are evaluated accordingly.… More > Graphic Abstract