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  • Open Access


    Flexible Biofoams Based on Furanics and Fatty Acids Esterified Tannin

    Elham Azadeh1, Ummi Hani Abdullah2,3, Christine Gerardin1,*, Antonio Pizzi1,*, Philippe Gerardin1, Cesar Segovia4

    Journal of Renewable Materials, Vol.11, No.10, pp. 3625-3645, 2023, DOI:10.32604/jrm.2023.030373

    Abstract Water repellant, flexible biofoams using tannin esterified with various fatty acid chains, namely lauric, palmitic and oleic acids, by reaction with lauryl chloride, palmitoyl chloride, and oleyl chloride were developed and their characteristics compared with the equivalently esterified rigid biofoams. Glycerol, while initially added to control the reaction temperature, was used as a plasticizer yielding flexible biofoams presenting the same water repellant character that the equivalent rigid foams. Acetaldehyde was used as the cross-linking agent instead of formaldehyde, as it showed a better performance with the esterified tannin. The compression results showed a significant decrease… More >

  • Open Access


    Higher Order OAM Mode Generation Using Wearable Antenna for 5G NR Bands

    Shehab Khan Noor1, Arif Mawardi Ismail1, Mohd Najib Mohd Yasin1,*, Mohamed Nasrun Osman1, Thennarasan Sabapathy1, Shakhirul Mat Salleh2, Ping Jack Soh3, Ali Hanafiah Rambe4, Nurulazlina Ramli5

    Computer Systems Science and Engineering, Vol.47, No.1, pp. 537-551, 2023, DOI:10.32604/csse.2023.037381

    Abstract This paper presents a flexible and wearable textile array antenna designed to generate Orbital Angular Momentum (OAM) waves with Mode +2 at 3.5 GHz (3.4 to 3.6 GHz) of the sub-6 GHz fifth-generation (5G) New Radio (NR) band. The proposed antenna is based on a uniform circular array of eight microstrip patch antennas on a felt textile substrate. In contrast to previous works involving the use of rigid substrates to generate OAM waves, this work explored the use of flexible substrates to generate OAM waves for the first time. Other than that, the proposed antenna… More >

  • Open Access



    Fangzhou Wanga,* , Gennifer A. Rileyb, Munonyedi Egboc, Melanie M. Derbyb, Gisuk Hwangc, Xianglin Lia,†

    Frontiers in Heat and Mass Transfer, Vol.15, pp. 1-8, 2020, DOI:10.5098/hmt.15.1

    Abstract This study conducts pore-scale simulations and experiments to estimate the permeability of two different types of porous materials: metal foams and sintered copper particles with porosities of approximately 0.9 and 0.4, respectively. The integration of micro X-ray computed tomography with pore-scale computational fluid dynamics simulations develops a unique tool to capture the pore-scale geometry of porous media and accurately predict non-isotropic permeability of porous media. The pore-scale simulation not only results in improved prediction accuracy but also has the capability to capture non-isotropic properties of heterogeneous materials, which is a huge challenge for empirical correlations,… More >

  • Open Access


    Hydrolysable Chestnut Tannin Extract Chemical Complexity in Its Reactions for Non-Isocyanate Polyurethanes (NIPU) Foams

    Elham Azadeh1, Antonio Pizzi1,2,*, Christine Gerardin-Charbonnier1,*, Philippe Gerardin1

    Journal of Renewable Materials, Vol.11, No.6, pp. 2823-2848, 2023, DOI:10.32604/jrm.2023.027651

    Abstract Non-isocyanate polyurethane (NIPU) foams from a commercial hydrolysable tannin extract, chestnut wood tannin extract, have been prepared to determine what chemical species and products are taking part in the reactions involved. This method is based on two main steps: the reaction with dimethyl carbonate and the formation of urethane bonds by further reaction of the carbonated tannin with a diamine-like hexamethylene diamine. The hydroxyl groups on the tannin polyphenols and on the carbohydrates intimately linked with it and part of a hydrolysable tannin are the groups involved in these reactions. The carbohydrate skeleton of the… More > Graphic Abstract

    Hydrolysable Chestnut Tannin Extract Chemical Complexity in Its  Reactions for Non-Isocyanate Polyurethanes (NIPU) Foams

  • Open Access


    Interaction of Foam and Microemulsion Components in Low-Tension-Gas Flooding

    Jing Zhao, Jun Yang*

    FDMP-Fluid Dynamics & Materials Processing, Vol.19, No.7, pp. 1951-1961, 2023, DOI:10.32604/fdmp.2023.026115

    Abstract Low-Tension-Foam (LTF) flooding is an emerging enhanced oil recovery technique for low-permeability carbonate reservoirs. Foam capacity is closely related to the salinity environment (or, equivalently, the phase behavior of the oil/water/surfactant system). Therefore, the interactions between microemulsion and foam components are of primary importance in the LTF process. In this study, the phase behavior of an oil/water/surfactant system under equilibrium is analyzed, firstly by assuming perfect mixing. Meanwhile, the formation kinetics of microemulsion are monitored through a novel low-field NMR technique, which is able to provide quantitative assessment on the microemulsion evolution characteristics. Then, foam More >

  • Open Access


    Preparation and Study of Borosilicate Foam Glass with High Thermal Insulation and Mechanical Strength

    Yiwen Zhang1, Jianjun Xie1,*, Minghui Sun1, Shaolong Wang1, Tengfei Xu2,3, Yonggen Xu2,3, Xiaoqing Ding2,3, Ying Shi1, Lei Zhang1

    Journal of Renewable Materials, Vol.11, No.5, pp. 2125-2141, 2023, DOI:10.32604/jrm.2023.025127

    Abstract Foam glass is a kind of green building material that is widely used because of its excellent thermal insulation and mechanical properties. In this study, the borosilicate foam glass was fabricated by powder sintering method using recycled soda lime waste glass, quartz, and borax as the primary raw materials. CaCO3 was used as a foaming agent and Na2CO3 as a flux agent. Results showed that as the quartz content decreases from 30 to 17.5 wt.% and borax content increases from 5 to 17.5 wt.%, the pore size, porosity, and thermal insulation of borosilicate foam glass increase significantly, while… More > Graphic Abstract

    Preparation and Study of Borosilicate Foam Glass with High Thermal Insulation and Mechanical Strength

  • Open Access


    Improved Beam Steering Method Using OAM Waves

    Nidal Qasem*, Ahmad Alamayreh

    Computer Systems Science and Engineering, Vol.46, No.1, pp. 417-431, 2023, DOI:10.32604/csse.2023.035603

    Abstract Orbital Angular Momentum (OAM) is an intrinsic feature of electromagnetic waves which has recently found many applications in several areas in radio and optics. In this paper, we use OAM wave characteristics to present a simple method for beam steering over both elevation and azimuth planes. The design overcomes some limitations of traditional steering methods, such as limited dynamic range of steering, the design complexity, bulky size of the steering structure, the limited bandwidth of operation, and low gain. Based on OAM wave characteristics, the proposed steering method avoids design complexities by adopting a simple… More >

  • Open Access


    Pilot Test for Nitrogen Foam Flooding in Low Permeability Reservoir

    Xinyu Zhou1,2, Jia Huang1,2, Yuchen Qian1,2, Wenli Luo1,2, Lisha Qi3, Jie Wang3, Zhibin Jiang3, Hao Kang4,*

    Energy Engineering, Vol.120, No.3, pp. 763-774, 2023, DOI:10.32604/ee.2023.025893


    Due to the characteristics of reservoir formation, the producing level of low permeability reservoir is relatively very low. It is hard to obtain high recovery through conventional development schemes. Considering the tight matrix, complex fracture system, low production level of producers, and low recovery factor of M block in Xinjiang oilfield, it is selected for on-site pilot test of nitrogen foam flooding. Detailed flooding scheme is made and the test results are evaluated respectively both for producers and injectors. The pressure index, filling degree, and fluid injection profile are found to be all improved in injectors

    More >

  • Open Access


    Cooperative NOMA Based on OAM Transmission for Beyond 5G Applications

    Mohammad Alkhawatrah*

    Computer Systems Science and Engineering, Vol.45, No.2, pp. 1187-1197, 2023, DOI:10.32604/csse.2023.030699

    Abstract Cooperative non-orthogonal multiple access (NOMA) is heavily studied in the literature as a solution for 5G and beyond 5G applications. Cooperative NOMA transmits a superimposed version of all users’ messages simultaneously with the aid of a relay, after that, each user decodes its own message. Accordingly, NOMA is deemed as a spectral efficient technique. Another emerging technique exploits orbital angular momentum (OAM), where OAM is an attractive character of electromagnetic waves. OAM gathered a great deal of attention in recent years (similar to the case with NOMA) due to its ability to enhance electromagnetic spectrum… More >

  • Open Access


    CO2-Responsive Smart Foams Stabilized by an Extremely Rigid Bio-Based Surfactant

    Weishan Tang, Xin Feng, Caiyun Lin, Xiaoping Rao*

    Journal of Renewable Materials, Vol.11, No.2, pp. 523-538, 2023, DOI:10.32604/jrm.2022.022809

    Abstract Environment friendly and intelligent surfactants have attracted great attention in recent years. A bio-based CO2 responsive surfactant rosin acid dimaleimide choline (R-BMI-C) with an extremely rigid skeleton was prepared using rosin and choline as raw materials by Diels-Alder addition reaction and acid-base neutralization reactions. Its structure was confirmed by IR and 1H NMR spectra. The foams’ properties of R-BMI-C could be adjusted by bubbling CO2/N2 to change the structure of the surfactant. At pH 10.4, R-BMI-C forms an unstable foam with a half-life of 1.5 h. When the pH was reduced to 7.4 by bubbling CO2, R-BMI-C… More > Graphic Abstract

    CO<sub>2</sub>-Responsive Smart Foams Stabilized by an Extremely Rigid Bio-Based Surfactant

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