Manoj Kr. Triveni^*, Dipak Sen, RajSekhar Panua

Frontiers in Heat and Mass Transfer, Vol.6, pp. 1-6, 2015, DOI:10.5098/hmt.6.2

Abstract A numerical investigation through laminar natural convection has been executed to illuminate the effect of curvature ratio in an arch enclosure filled with water. The left side wall of the cavity is maintained at a higher temperature than that of the right side wall while the other walls are kept insulated. The governing equations such as continuity, momentum and energy equation are solved by finite volume method. The effect of pertinent parameters such as curvature ratio (1≤ CR ≤ 1.5) and Rayleigh number (1×10⁴ ≤ Ra ≤ 1×10⁶) and) on heat transfer are calculated by commercial More >

J. N. Chung^*, Kun Yuan

Frontiers in Heat and Mass Transfer, Vol.6, pp. 1-7, 2015, DOI:10.5098/hmt.6.1

Abstract Chilldown or quenching is a complicated process that initiates the cryogenic fluid line transport, and it involves unsteady two-phase heat and mass transfer. To advance our understanding of this process, we have reviewed recent experimental investigations. The chilldown process can be generally divided into three regimes: film boiling, transition boiling and nucleate boiling, and each regime is associated with a different flow pattern and heat transfer mechanism. Under low flow rate conditions, it is concluded that the two-phase flow regime is dispersed flow in the film boiling regime. The dispersed liquid phase is in the More >

Miguel Ángel Ramírez¹, Luis Alfonso^†, Patricia González², Juan Reinerio Fagundo², Margaret Suarez³, Clara Melian³, Tania Rodríguez¹, Carlos Peniche^4,*

Journal of Renewable Materials, Vol.3, No.1, pp. 73-80, 2015, DOI:10.7569/JRM.2014.634116

Abstract The demineralization kinetics of deproteinized lobster shells using CO₂ were studied. Demineralization reaction proceeds until the concentration of Ca⁺² in solution reaches an equilibrium value. The introduction of a cation exchange resin (cationite), in an open system for CO₂ , allows replacement of the solution Ca²⁺ ions by Na⁺ ions, whereby the equilibrium shifts and an effective dissolution of the exoskeletons’ calcite is achieved. The mathematical relationships between the conductivity of the solution and the concentrations of major ions, the rate constants and kinetic parameters of the reaction in the absence and presence of the resin were obtained. More >

Yogesh K. Murugesan¹, Damiano Pasini², Alejandro D. Rey^1,*

Journal of Renewable Materials, Vol.3, No.1, pp. 56-72, 2015, DOI:10.7569/JRM.2014.634124

Abstract This review on self-assembly in biological fi brous composites presents theory and simulation to elucidate the principles and mechanisms that govern the thermodynamics, material science, and rheology of biological anisotropic soft matter that are involved in the growth/self-assembly/material processing of these materials. Plant cell wall, a multi-layered biological fi brous composite, is presented as a model biological system to investigate self-assembly mechanisms in nature’s material synthesis. In order to demonstrate the universality of the presented models and the mechanisms investigated, references to other biological/ biomimetic systems are made when applicable. The integration of soft matter More >

Raquel Fernández^*, Connie Ocando, Susana C. M. Fernandes, Arantxa Eceiza, Agnieszka Tercjak

Journal of Renewable Materials, Vol.3, No.1, pp. 49-55, 2015, DOI:10.7569/JRM.2014.634134

Abstract The main goal of this work was the development of photoactive multilayer fi lms. Taking into account that chitosan is a biodegradable, biocompatible, nontoxic, and antibacterial biopolymer, the fabrication of chitosanbased multilayer fi lms can be an interesting pathway to obtain biopolymer-based fi lms in which properties can be combined with a light-responsive material, such as an azobenzene-containing polymer. In particular, the layer-by-layer technique was used for the fabrication of the optically active fi lms consisting of alternating layers of chitosan and an azopolymer. The infl uence of the pH and the number of bilayers More >

Sławomir Michałowski, Aleksander Prociak^*

Journal of Renewable Materials, Vol.3, No.1, pp. 14-18, 2015, DOI:10.7569/JRM.2014.634131

Abstract This article describes the effects of the modifi cation of polyurethane system with rapeseed oil-based polyol on the cell structure and physical-mechanical properties of conventional fl exible polyurethane foams. The foams were prepared by substituting a part of the petrochemical polyether-polyols mixture with the bio-polyol based on rapeseed oil. Selected physical-mechanical properties of these foams were examined and compared to the properties of reference foam. The properties such as apparent density, resilience, comfort factor and stress-strain characteristics were analyzed in compression tests. It was found that the modifi cation of polyurethane formulation with rapeseed oil-based More >

Tamara Calvo-Correas¹, Mirna A. Mosiewicki², M. Angeles Corcuera¹, Arantxa Eceiza¹, Mirta I. Aranguren^2,*

Journal of Renewable Materials, Vol.3, No.1, pp. 3-13, 2015, DOI:10.7569/JRM.2014.634132

Abstract Rigid polyurethane foams were synthesized by using a vegetable oil-based polyol and 4,4-diphenylmethane diisocyanate prepolymer as the majority of reactives,. The polyol was produced by hydroxylation of crude linseed oil with performic acid generated in situ by the reaction of hydrogen peroxide and formic acid. The characterization by FTIR, H1 NMR, iodine and hydroxyl values of the polyol and its comparison with the original linseed oil supports the success of the reaction. The reference foam was subsequently modifi ed by substituting part of the linseed oil polyol with glycerol, diethylene glycol, and a polyethylene glycol More >

Pronob Gogoi, Dhaneswar Das, Shyamalima Sharma, Swapan K. Dolui^*

Journal of Renewable Materials, Vol.3, No.2, pp. 151-159, 2015, DOI:10.7569/JRM.2014.634129

Abstract Alkyd resins based on Jatropha curcas oil with different molar ratios of phthalic anhydride (PA) and maleic anhydride (MA) were prepared by alcoholysis followed by polyesterifi cation reaction. The progress of the reaction was traced by the determination of acid value at regular time intervals. From the kinetic study the extent of the reaction was found in the range of 52.4–61.2%. The prepared resins were blended with a commercially available fast-curing epoxy resin in order to improve the properties like curing time, chemical resistance, tensile strength, and thermal stability. The morphology study of the blends More >

X. Li¹, A. Pizzi^1,2,*, X. Zhou^3,*, V. Fierro⁴, A. Celzard⁴

Journal of Renewable Materials, Vol.3, No.2, pp. 142-150, 2015, DOI:10.7569/JRM.2014.634117

Abstract Tannin/furanic foams, typically 95% composed of materials of natural origin such as prorobinetinidin/ profi setinidin tannins and furfuryl alcohol, are potential alternatives to oil-based synthetic foams such as phenol-formaldehyde, and polyurethane foams. This article describes the development of second generation tannin/furanic foams, which are not only formaldehyde free, but also use nonvolatile, nontoxic aldehydes. Both glyoxal and glutaraldehyde were tried to substitute formaldehyde in tannin/furanic foams. The physical properties of these new foams are described and discussed. It was found that glutaraldehyde can totally substitute formaldehyde during tannin/furanic foam preparation, but that glyoxal cannot. The More >

Zhiqiang Sun, Ranlong Duan, Han Zhang, Xuan Pang^*, Xianhong Wang, Xuesi Chen

Journal of Renewable Materials, Vol.3, No.2, pp. 82-90, 2015, DOI:10.7569/JRM.2014.634133

Abstract A series of bimetallic Salen aluminum (III) complexes with different steric substituents were synthesized. These complexes were used as catalysts to produce polylactide in the ring-opening polymerization of racemic lactide. A kinetic research of polymerization demonstrated that the steric substituents on the phenolate ring of the complexes had remarkable infl uence on the stereoselectivity and the polymerization activity. The highest stereoselectivity was obtained with bulky substituent on the ortho position of the salicylidene moieties. Kinetic studies using all these complexes indicated that the polymerizations were fi rst-ordered with respect to lactide monomers. All these complexes More >