A.Toshimitsu Yokobori Jr^1,*, Go. Ozeki¹, Toshihito OHMI^1,2, Tadashi Kasuya³, Nobuyuki Ishikawa⁴, Manabu Enoki³, Satoshi Minamoto⁵

The International Conference on Computational & Experimental Engineering and Sciences, Vol.22, No.2, pp. 119-119, 2019, DOI:10.32604/icces.2019.05177

Abstract Authors have been founded that hydrogen diffusion and concentration behavior for notched specimens of multi-materials with space distribution of various material properties were dominated not only by the space gradient of hydrostatic stress caused by the notch tip, ∇σ_p but also by that of diffusion coefficient, ∇D(T, HV, ε_p) caused by space distributions of temperature, hardness and plastic strain due to multi-materials. In this research, on the basis of our proposed coupled analysis of heat transfer induced thermal stress driven hydrogen diffusion, the effect of ∇D(T, HV, ε_p) ) on hydrogen concentration behavior was clarified by solving the problem of… More >

Md. Anwar Hossain^1,2, Lee Hwei Voon^1,*

Journal of Renewable Materials, Vol.7, No.8, pp. 731-748, 2019, DOI:10.32604/jrm.2019.04703

Abstract Synthesizing polyol-based ester from biomass feedstocks for the preparation of biolubricant overcomes the dependence on petroleum oil usage. Albeit biomass-derived bio-oil is an alternative for the production of polyol ester, upgrading is essential prior to use as biolubricant. Levulinic acid (LA), obtained from bio-oil was applied for the catalytic esterification with two polyols, e.g., trimethylolpropane (TMP) and pentaerythritol (PE), in the presence of mixed-ligand Ni(II), Co(II), and Fe(II) complexes as catalyst. New mixed-ligand coordination complexes with empirical formula; [Ni(Phe)(Bpy)Cl].H2O, [Co(Phe)(Bpy)Cl].H2O, and [Fe(Phe)(Tyr)Cl].H2O were synthesized by the reaction of ligands [L-phenylalanine (Phe), 4,4'-bipyridine (Bpy), and L-tyrosine (Tyr)] with metal chloride salts… More >

D.W. Brenner, O.A. Shenderova, D.A. Areshkin, J.D. Schall¹, S.-J. V. Frankland²

CMES-Computer Modeling in Engineering & Sciences, Vol.3, No.5, pp. 643-674, 2002, DOI:10.3970/cmes.2002.003.643

Abstract The derivation of a bond-order potential energy function and a self-consistent tight-binding scheme is presented, followed by a survey of the application of these methods to calculating properties of carbon nanostructures. The modeling studies discussed include properties of functionalized and kinked carbon nanotubes, Raman shifts for hydrogen stored in nanotubes, nanotubes in a composite, properties of nanotubes in applied potential (electrical) fields, and structures and properties of nanocones, nanodiamond clusters and rods, and hybrid diamond-nanotube structures. More >

Poonam Trivedi¹, Jens Schaller², Jan Gustafsson¹, Pedro Fardim^1,3*

Journal of Renewable Materials, Vol.5, No.5, pp. 400-409, 2017, DOI:10.7569/JRM.2017.634143

Abstract In the present study, we report the supramolecular design of cellulose-sulfonate hydrogel beads by blending water soluble sodium cellulose ethyl sulfonate (CES) with the pretreated cellulose in sodium hydroxide-ureawater solvent system at −6 °C followed by coagulation in the 2M sulfuric acid system. The increasing of CES amount from 10% to 90% had a substantial effect on the viscosity and storage (G′) and loss (G″) moduli of the blended solutions. The CES concentration up to 50% in blends led to the formation of physically stable hydrogels after coagulation in acidic medium at pH-1 and showed the retention of nearly the… More >

Shegufta Shetranjiwalla, Shaojun Li, Laziz Bouzidi, Suresh S. Narine^*

Journal of Renewable Materials, Vol.5, No.5, pp. 333-344, 2017, DOI:10.7569/JRM.2017.634102

Abstract The impact of polymerization protocol on phase structure and properties of entirely lipid-derived thermoplastic poly(ester urethane)s (TPEU)s was investigated. The TPEUs were synthesized from 1,7-heptamethylene diisocyanate, polyester diols and 1,9-nonanediol (ND) as chain extender. A two-stage polymerization method was used to prepare two TPEUs; one in which ND was added in the first stage of polymerization as part of the prepolymer and another in the second stage after the prepolymer was formed. Two very different morphologies exhibiting different degrees of phase separation were obtained, driven by the sequence of addition of the chain extender. The incorporation of the chain extender… More >

Matthew D. Lindemer¹, Suresh G. Advani^2,*, Ajay K. Prasad²

CMES-Computer Modeling in Engineering & Sciences, Vol.117, No.3, pp. 527-553, 2018, DOI:10.31614/cmes.2018.00481

Abstract The lattice Boltzmann method (LBM) is used to simulate the growth of a solid-deposit on the walls of a circular tube resulting from a gas-to-solid reaction and precipitation process. This process is of particular interest for the design of reactors for the production of hydrogen by the heterogeneous hydrolysis of steam with Zn vapor in the Zn/ZnO thermochemical cycle. The solid deposit of ZnO product on the tube wall evolves in time according to the temporally- and axially-varying convective-diffusive transport and reaction of Zn vapor with steam on the solid surface. The LBM is well-suited to solving problems with coupled… More >

Kentaro Doi^1,2, Ikumi Onishi¹, Satoyuki Kawano^1,3

CMES-Computer Modeling in Engineering & Sciences, Vol.77, No.2, pp. 113-136, 2011, DOI:10.3970/cmes.2011.077.113

Abstract Hydrogen technologies are currently one of the most actively researched topics. A lot of researches have tied to enhance their energy conversion efficiencies. In the present study, numerical analyses have been carried out focusing on hydrogen-storage carbon materials which are expected to realize high gravimetric and volumetric capacities. In particular, dissociative adsorption processes of H₂ molecules above graphene surfaces have been investigated by ab initio molecular dynamics. The present results indicate that a steric graphene surface plays an important role in enhancing the charge transfer which induces dissociation of H₂ and adsorption of H atoms on the surface. The dissociation… More >

J. Lufrano¹, P. Sofronis¹

CMES-Computer Modeling in Engineering & Sciences, Vol.1, No.2, pp. 119-132, 2000, DOI:10.3970/cmes.2000.001.279

Abstract Transient hydrogen diffusion and hydride formation coupled with material deformation are studied in Zr-2.5Nb alloys used in the pressure tubes of CANDU nuclear generating stations. The energetics of the hydride formation is revisited and the terminal solid solubility of hydrogen in solution is defined on the basis of the total elastoplastic work done on the system by the forming hydride and the external loads. Probabilistic precipitation of hydride is modeled in the neighborhood of a crack tip under mode I plane strain loading and a uniform initial hydrogen concentration below the stress free terminal solid solubility. Finite element analysis is… More >

SouadMorsli^1,*, Amina Sabeur¹, Mohammed El Ganaoui²

FDMP-Fluid Dynamics & Materials Processing, Vol.11, No.4, pp. 342-353, 2015, DOI:10.3970/fdmp.2015.011.342

Abstract The aim of this work is the numerical simulation of the combustion of hydrogen with air in a burner and the numerical solution of local entropy generation rate in the combustion chamber. The effects of equivalence ratio φ and oxygen percentage γ on combustion and entropy generation rates are studied for different φ(ranging from 0 to 1.0) and γ values (ranging from 10 to 30%). The predictions show that the increase of φ (or the decrease of λ ) reduces notably the reaction rate levels. The equations of continuity, of energy and momentum are solved by volume finite using commercial… More >

K. Lahmer¹, R. Bessaïh¹, A. Scipioni², M. El Ganaoui²

FDMP-Fluid Dynamics & Materials Processing, Vol.10, No.1, pp. 149-162, 2014, DOI:10.3970/fdmp.2014.010.149

Abstract This paper summarizes the outcomes of a numerical study about the phenomenon of hydrogen absorption in an axisymmetric tank geometry containing magnesium hydride heated to 300˚C and at moderate storage pressure 1 MPa. The governing equations are solved with a fully implicit finite volume numerical scheme (as implemented in the commercial software FLUENT). Different kinetic reaction equations modeling hydrogen absorption are considered and the related numerical simulations are compared with experimental results. Spatial and temporal profiles of temperature and concentration in hydride bed are plotted. More >