Shun Kang¹, Xun Yuan¹, Changwu Liu^1,*, Yulin Chen¹, Xianliang Zhou¹, Haikuan Wu², Zhiguo Ma³

Journal of Renewable Materials, Vol.10, No.12, pp. 3521-3538, 2022, DOI:10.32604/jrm.2022.021694

Abstract Part of the tunnel spoil can not be used for concrete due to alkali-aggregate reaction (AAR). Water is an indispensable condition for AAR, so separating the alkali-aggregate from water is of great benefit to controlling the AAR. This paper investigates the modification of concrete and aggregate by hydrophobic impregnation and organic coating and then evaluates their waterproof and mechanical properties by dynamic contact angle (DCA), ultrasonic wave velocity, scanning electron microscope (SEM), nuclear magnetic resonance (NMR), and so on. For waterproofness, hydrophobic impregnation and organic coating can both improve the waterproofness of concrete and aggregate. The organic coating is suitable… More >

Supreet Singh^1,2, Nitin Mittal¹, Urvinder Singh², Rohit Salgotra², Atef Zaguia³, Dilbag Singh^4,*

CMC-Computers, Materials & Continua, Vol.71, No.2, pp. 3445-3462, 2022, DOI:10.32604/cmc.2022.023004

Abstract This paper provides a new optimization algorithm named as tunicate swarm naked mole-rat algorithm (TSNMRA) which uses hybridization concept of tunicate swarm algorithm (TSA) and naked mole-rat algorithm (NMRA). This newly developed algorithm uses the characteristics of both algorithms (TSA and NMRA) and enhance the exploration abilities of NMRA. Apart from the hybridization concept, important parameter of NMRA such as mating factor is made to be self-adaptive with the help of simulated annealing mutation operator and there is no need to define its value manually. For evaluating the working capabilities of proposed TSNMRA, it is tested for 100-digit challenge (CEC… More >

Medjda Amari¹, Kamel Khimeche^1,*, Abdelkader Hima² , Redouane Chebout³, Abderahmane Mezroua¹

Journal of Renewable Materials, Vol.9, No.3, pp. 463-475, 2021, DOI:10.32604/jrm.2021.013680

Abstract Recently, the exploitation of renewable plant resources in the formulation of adhesives is very promising for their availability at low coast, as well as their richness in biomolecules such as polyphenols. In this way, many research studies tannins extracted from different sources such as mimosa, quebracho, and pine have been the subject of very satisfactory recent studies. In this paper, a new complete characterization of the tannins extracted from the bark of eucalyptus globulus harvested from two regions in Algeria was achieved. The structural characterization enabled us to confirm the richness in condensed tannins, particularly in procyanidin and prodelphinidin units.… More >

Dragomir Vassilev^1,*, Nadezhda Petkova², Yulian Tumbarski³, Milena Koleva¹, Panteley Denev²

Journal of Renewable Materials, Vol.8, No.6, pp. 675-686, 2020, DOI:10.32604/jrm.2020.09279

Abstract Undenicylic acid (10:1) is known as an antifungal agent and an active ingredient of many topical medicines [1–6]. The present research investigates the preparation of aliphatic esters of 10-undecylic acid with butanol and i-amyl alcohol by the conventional and ultrasound-assisted syntheses as well as the structural elucidation of the resulting compounds, by FTIR and NMR spectroscopy. The antimicrobial properties of the obtained 10-undecylenic esters were tested against Gram-positive bacteria (Staphylococcus aureus; Enterococcus faecalis; Listeria monocytogenes), Gram-negative bacteria (Escherichia coli; Salmonella sp.) and filamentous fungi (Penicillium sp.; Aspergillus niger; Fusarium moniliforme) using the conventional agar-well diffusion assay. The results demonstrated that… More >

Nadezhda Petkova^1,*, Radka Arabadzhieva¹, Dragomir Vassilev², Gergana Gencheva¹, Yulian Tumbarski³, Tsveteslava Ignatova-Ivanova⁴, Sevginar Ibryamova⁴, Mina Todorova¹, Milena Koleva², Panteley Denev¹

Journal of Renewable Materials, Vol.8, No.4, pp. 365-381, 2020, DOI:10.32604/jrm.2020.09292

Abstract Microwave-assisted irradiation was performed for esterification of chicory inulin with high degree of polymerization with acetic anhydride without a solvent only with a catalyst. The resulting esters were characterized by melting point, hydrophilic-lipophilic balance, thin-layer chromatography, ultraviolet spectroscopy, Fourier transform infrared spectroscopy (FTIR) and nuclear magnetic resonance (NMR) spectroscopy. Inulin acetate demonstrated a high degree of acetylation (2.5–3.0) and presented a white, water-insoluble substance with bitter taste. The FTIR and NMR spectra confirmed esterification and demonstrated the incorporation of hydrophobic residue to the water soluble inulin backbone. Swelling capacity, water holding, oil-holding capacities, the foamability, foam stability and emulsifying properties… More >

Ibtissem Moussa^1,2, Ramzi Khiari^1,3,4,*, Ali Moussa², Gérard Mortha⁴, Mohamed Farouk Mhenni¹

Journal of Renewable Materials, Vol.7, No.4, pp. 345-354, 2019, DOI:10.32604/jrm.2019.04011

Abstract The most abundant phenolic biopolymer in the biosphere is the lignin. This phenolic biopolymer commonly exists in combination with polysaccharides and other cell wall components. In this study, the solvent system dioxane-water is used to extract lignin, which is considered as unaltered native lignin. The dioxane lignin extracted from fig stems was characterized regarding to its structural feature, quantification of its functional groups, molecular weight, and evaluation of its thermal properties. Purity and molecular weight distribution of the studied lignin indicated that isolated lignin contained a low amount of sugar (c.a. 19%) and had a high weight-average molecular weight (10… More >

F. J. Santiago-Medina¹, A. Pizzi^{1, 2*}, M. C. Basso¹, L. Delmotte³, S. Abdalla²

Journal of Renewable Materials, Vol.5, No.5, pp. 388-399, 2017, DOI:10.7569/JRM.2017.634142

Abstract The reaction of a desulphurized kraft lignin with hexamethylene diamine as a model of a polyamine has been investigated. For this purpose, guaiacol was also used as a lignin model compound and treated under similar conditions. Solid state CP-MAS 13C NMR, FTIR and MALDI-TOF spectroscopy studies revealed that polycondensation compounds leading to resins were obtained by the reaction of the amines with the phenolic and aliphatic hydroxy groups of lignin. Simultaneously a second reaction leading to the formation of ionic bonds between the same groups occurred. These new reactions have been clearly shown to involve several phenolic and alcohol hydroxyl… More >

Louis C. Muller^1*, Sanette Marx¹, Hermanus C.M. Vosloo²

Journal of Renewable Materials, Vol.5, No.1, pp. 67-80, 2017, DOI:10.7569/JRM.2016.634130

Abstract This work reports a study of polyol synthesis through liquefaction of technical lignins in crude glycerol by means of 1H and 31P NMR spectroscopy. The polyols are intended for preparation of polyurethane foam; thus, it is important to know how different lignin types as well as crude glycerol influence and contribute to the final polyol hydroxyl contents. Polyols prepared from organosolv lignin, kraft lignin and lignosulphonate had hydroxyl numbers suitable for rigid foam of 435, 515 and 529 mgKOH/g, respectively. The polyols differed in composition with glycerol, showing significant variation. During liquefaction the glycerol content was mostly reduced through bonding… More >