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  • Open Access

    ABSTRACT

    Molecular Dynamics Simulations of Carbon Nanotubes Cross-Bonding by Proton Irradiation

    N. J. Lee, C.R. Welch1

    The International Conference on Computational & Experimental Engineering and Sciences, Vol.13, No.1, pp. 11-12, 2009, DOI:10.3970/icces.2009.013.011

    Abstract Carbon nanotubes have significant potential as the basis for super infrastructure material. The shear modulus of carbon nanotube ensembles is relatively low, comparable to graphite, as the carbon nanotubes interact via weak van der Waals forces. Unmodified, their intermolecular interactions are insufficient to take full advantage of the extraordinarily high strengths predicted for carbon nanotube-based fibers. Thus, a key to their use in high-strength materials is developing strong bonds between these molecules. In this study, we examine the potential development of covalent bonds between carbon nanotube pairs cross-bonded by proton bombardment using molecular dynamics simulation. Covalent bond formation between aligned… More >

  • Open Access

    ARTICLE

    The Effects of Gamma Irradiation on Molecular Weight, Morphology and Physical Properties of PHBV/Cloisite 30B Bionanocomposites

    Kahina Iggui1,2,*, Mustapha Kaci1, Mohamed Mahlous3, Nicolas Le Moigne4, Anne Bergeret4

    Journal of Renewable Materials, Vol.7, No.9, pp. 807-820, 2019, DOI:10.32604/jrm.2019.06778

    Abstract In this paper, the effects of gamma irradiation on Cast poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) and PHBV/Cloisite 30B (C30B) (3 wt%) bionanocomposite prepared by melt compounding, were evaluated at various doses, i.e., 5, 15, 20, 50 and 100 kGy at room temperature in air. Changes in molecular weight, morphology and physical properties were investigated. The study showed that the main degradation mechanism occurring in gamma irradiation in both Cast PHBV and C-PHBV/3C30B bionanocomposite is chain scission, responsible for the decrease of molecular weight. Differential scanning calorimetry (DSC) data indicated a regular decrease in crystallization temperature, melting temperature and crystallinity index for all irradiated… More >

  • Open Access

    ARTICLE

    Microwave-Assisted Isolation and Acetylation of Inulin from Helianthus Tuberosus L Tubers

    Nadezhda Petkova1,*, Gergana Gencheva1, Dragomir Vassilev2, Milena Koleva2, Albert Krastanov3, Panteley Denev1

    Journal of Renewable Materials, Vol.6, No.7, pp. 671-679, 2018, DOI:10.32604/JRM.2018.00001

    Abstract Jerusalem artichoke (Helianthus tuberosus L.) tubers are industrial crop considered as a promising source for inulin production. “Green” method was performed for accelerated inulin extraction from Helianthus tuberosus L. tubers by the application of microwave irradiation. Further pretreatment of the water extract with acetone and ethanol yielded inulin (20%) with purity 89% and degree of polymerization 18. Jerusalem artichoke inulin was characterized by FTIR and NMR spectroscopy. For the first time eco-friendly synthesis of acetylated Jerusalem artichoke inulin was performed by the reaction with acetic anhydride, without toxic solvent, but only with sodium acetate as catalyst under microwave irradiation for… More >

  • Open Access

    ARTICLE

    Conductive Polymer Composites Synthesized from Diacetylene-Functionalized Linseed Oil and MWCNT: Gamma Irradiation and Organic Vapor Sensing

    A. Ramírez-Jiménez1*, S. Hernández López1, E. Bucio2, E. Vigueras Santiago1

    Journal of Renewable Materials, Vol.5, No.2, pp. 132-144, 2017, DOI:10.7569/JRM.2016.634138

    Abstract Epoxidized linseed oil (ELO) was synthesized and functionalized with propargylamine (PA) or 3-ethynylaniline (EA) and the products were crosslinked to obtain the diacetylene-functionalized epoxidized linseed oil polymers which were used as matrices in the preparation of the composites with multiwalled carbon nanotubes (MWCNTs). Electrical resistance at percentages between 4 and 20 wt/wt% of filler was measured and the percolation threshold was calculated, obtaining 1.2 and 1.7% for the composites with EA and PA respectively. Low critical concentration evidenced a good dispersion of the MWCNTs without necessity of any modification. The final products were used in the sensing of acetone, chloroform… More >

  • Open Access

    ARTICLE

    Transient Bioheat Simulation of the Laser-Tissue Interaction in Human Skin Using Hybrid Finite Element Formulation

    Ze-Wei Zhang*, Hui Wang, Qing-Hua Qin∗,‡

    Molecular & Cellular Biomechanics, Vol.9, No.1, pp. 31-54, 2012, DOI:10.3970/mcb.2012.009.031

    Abstract This paper presents a hybrid finite element model for describing quantitatively the thermal responses of skin tissue under laser irradiation. The model is based on the boundary integral-based finite element method and the Pennes bioheat transfer equation. In this study, temporal discretization of the bioheat system is first performed and leads to the well-known modified Helmholtz equation. A radial basis function approach and the boundary integral based finite element method are employed to obtain particular and homogeneous solutions of the laser-tissue interaction problem. In the boundary integral based finite element formulation, two independent fields are assumed: intra-element field and frame… More >

  • Open Access

    ARTICLE

    Theoretical Analysis of Thermal Damage in Biological Tissues Caused by Laser Irradiation

    Jianhua Zhou, J. K. Chen, Yuwen Zhang

    Molecular & Cellular Biomechanics, Vol.4, No.1, pp. 27-40, 2007, DOI:10.3970/mcb.2007.004.027

    Abstract A bioheat transfer approach is proposed to study thermal damage in biological tissues caused by laser radiation. The laser light propagation in the tissue is first solved by using a robust seven-flux model in cylindrical coordinate system. The resulting spatial distribution of the absorbed laser energy is incorporated into the bioheat transfer equation for solving temperature response. Thermal damage to the tissue is assessed by the extent of denatured protein using a rate process equation. It is found that for the tissue studied, a significant protein denaturation process would take place when temperature exceeds about 53oC. The effects of laser… More >

  • Open Access

    ARTICLE

    A Molecular Dynamics Study of Irradiation Induced Cascades in Iron Containing Hydrogen

    E. Hayward1, C. Deo1

    CMC-Computers, Materials & Continua, Vol.16, No.2, pp. 101-116, 2010, DOI:10.3970/cmc.2010.016.101

    Abstract Damage cascades representative of those that would be induced by neutron irradiation have been simulated in systems of pure iron and iron containing 0.01 at.% hydrogen. Results from molecular dynamics simulations using three different embedded-atom method (EAM) type potentials are compared for primary knock-on atom energies of 5, 10, and 20 keV to assess the effect of hydrogen on the primary damage state. We examine the influence of hydrogen on the primary damage state due to a single radiation cascade. These results can serve as an atomistic database for methods and simulations for long time scale evolution of radiation damage. More >

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