A review on biomass‐based hydrogen production for renewable energy supply

This article gives an overview of the state‐of‐the‐art biomass‐based hydrogen production technologies. Various biological and thermochemical processes of biomass are taken into consideration to find the most economical method of hydrogen production. Biohydrogen generated by biophotolysis method, photo‐fermentation and dark fermentation is studied with respect to various feedstocks in Malaysia. The fermentation approaches of biohydrogen production have shown great potential to be a future substitute of fossil fuels. Dark fermentation method is a simple biological hydrogen production method that uses a variety of substrate and does not require any light as a source of energy. A promising future for biohydrogen production is anticipated by this process both industrially and commercially. Feasibility of hydrogen production from pyrolysis and water gasification of various biomass feedstock confirm that supercritical water gasification (SCWG) of biomass is the most cost‐effective thermochemical process. Highly moisturized biomass could be employed directly in SCWG without any high‐cost drying process. Indeed, a small amount of energy is required to pressurize hydrogen in the storage tank because of highly pressurized SCWG process. The cost of hydrogen produced by SCWG of biomass is about US$3/GJ (US$0.35/kg), which is extremely lower than biomass pyrolysis method (in the range of US$8.86/GJ to US$15.52/GJ) and wind‐electrolysis systems and PV‐electrolysis systems (US$20.2/GJ and US$41.8/GJ, respectively). The best feedstock for biomass‐based hydrogen production is identified based on the availability, location of the sources, processes required for the preparation of the feedstock and the total cost of acquiring the feedstock. The cheapest and most abundantly available biomass source in Malaysia is the waste of palm industry. Hydrogen production from palm oil mill effluent and palm solid residue could play a crucial role in the energy mix of Malaysia. Malaysia has this great capability to supply about 40% of its annual energy demand by hydrogen production from SCWG of palm solid waste. Copyright © 2015 John Wiley & Sons, Ltd.     

Synthesis and polymerization of 1,5-bis( N -carbazolyl)pentane with its structural and behavioral highlights

Carbazole, the well-known electron donor and hole-transporting organic light-emitting molecule was modified into 1,5-bis[N-carbazolyl]pentane (1,5-BNCP) by introducing the saturated pentane spacer. Such insertion fixed the certain space between growing polymer chains and demonstrated π–π stacking effect over its morphology and structure. Its contribution in improving the thermal stability and photosensitization was also investigated. The FT-IR and 1H NMR was used to characterize monomer. Morphology of subsequently polymerized material was seen under SEM. The position of polymerization and structural change were studied by FT-IR and XRD, respectively. Thermal study with reference to glass transition temperature and stability was analyzed by DSC and TGA. Optical properties of monomer and polymer were investigated by UV–visible and photoluminescent spectrophotometer. The material was found crystalline, thermally stable, highly photosensitized and white light emitter.     

Materials Sliding Wear Model Based on Energy Dissipation

A mathematical model is developed to correlate the volumetric wear of materials with the dissipation energy in sliding contacts. In the analysis, the wear of contacting materials originating from the energy loss due to friction process in the contact is studied. Two mechanisms responsible for energy loss at contact are considered. The first is the amount of energy spent to import plastic deformation and the second is the elastic energy of the particulate. The energy loss due to elastic and plastic deformation is calculated. The statistical loss of energy is calculated for two rough surfaces by the assumption that there is negligible change in the statistical parameters of the surface during wear. The model can be useful to predict the service lifetime of components and eventually structures. The results showed that the amount of dissipated energy and the volumetric loss increased with increasing normal load. Also, changing the normal load changed the rate of energy dissipation per unit sliding distance.     

Discrete Element Modeling (DEM) of the Vertically Vibrated Particle Bed

Discreet element modeling (DEM) is a computational tool used for detailed exploration of dynamic particle bed behaviors. One such application is the analysis of finely sized particle mixtures under the influence of external forces such as vertical vibration, which is difficult, if barely at all accessible for detailed experimental analysis. Here, we examined the differential density dynamic particle bed behaviors, by the application of a modified two dimensional DEM-fluid model that incorporates the gravity and fluid effects, to replicate some of the important experimental based observations of segregation, heaping, tilting, high density particles on top and bottom, and partition cell separation. The simulation results compared favorably with the reported literature on the density segregation attributes such as high density particles on top at vertical vibration frequency of 6.3 and 7 Hz with corresponding dimensionless acceleration magnitude of 1.6 and 2, convection currents at vertical vibration frequency of 30, 40, and 30 with corresponding dimensionless acceleration magnitude of 3.5, 4, and 3, layer separation at vertical vibration frequency of 7 Hz with corresponding dimensionless acceleration magnitude 2 and partition cell separation at vertical vibration frequency of 45 Hz and corresponding dimensionless acceleration magnitude of 2.25 for simulated glass and bronze particle mixture properties.     

Luminescence properties of Mn and Ni doped ZnS nanoparticles synthesized by capping agent

ZnS and transition metal (Mn and Ni) doped ZnS were synthesized by a simple chemical method using alkyl hydroxyl ethyl dimethyl ammonium chloride (HY) as capping agent. The structural and optical properties were studied using various techniques. FTIR and X-ray diffraction (XRD) can be used to identify the chemical bonding and crystal structure. The XRD analysis show that the particles are in cubic structure. The mean size of the nanoparticles calculated through Scherrer equation is in the range of 5–2.5 nm. Elemental dispersive analysis of doped samples reveals the presence of doping ions. The transmission electron microscopic studies show that the synthesized particles are in spherical shape. Optical characterization of both undoped and doped samples was carried out by ultraviolet–visible and photoluminescence spectroscopy. The absorption spectra of all the samples are blue shifted from the bulk ZnS.     

MPLS technology in wireless networks

Recently, there has been increasing demand for Multi-protocol label switching (MPLS) technology in most internet service provider networks. The application of MPLS technology in wireless networking is evolving. Therefore, next generation wireless networks are required to have IP mobility solutions with high reliability, low-latency handoffs, and trustworthy security. In this paper, we propose a novel multi-path mobility scheme for fast handoff to achieve these requirements. The scheme is based on MPLS multi-path forwarding and network coding based on modulo-p Galois finite field GF(p = 2 ⁿ ) arithmetic. The simulation results show that our proposed approach scales well to fulfill fast handoff/handover performance while providing security for transmitted data with minor bandwidth overhead.     

Products of thermodynamic parameters of the generalized charged rotating black hole and the Reissner–Nordström black hole with a global monopole

We investigate the thermodynamics of the Kerr–Newman–Kasuya black hole and the Reissner–Nordström black hole with a global monopole on inner and outer horizons. Products of surface gravities, surface temperatures, Komar energies, electromagnetic potentials, angular velocities, areas, entropies, horizon radii and irreducible masses at the Cauchy and event horizons are calculated. It is observed that the product of surface gravities, the surface temperature product and the product of Komar energies, electromagnetic potentials and angular velocities at horizons are not universal quantities for these black holes. Products of areas and entropies at the horizons are independent of black hole masses. The heat capacity is calculated for the generalized charged rotating black hole, and a phase transition is observed under certain conditions on r.     

Synthesis,Characterization, and Application Studies of Polyurethane Acrylate Thermoset Coatings: Effect of Hard Segment

The waterborne polyurethane acrylate coatings are smart option to reduce the environmental hazards. To evaluate the structure–property relationship, polyurethane acrylate coating dispersions were synthesized with aromatic and aliphatic hard segments. Furthermore, to evaluate the performance, dispersions were used to finish the cotton fabric. The dispersions were prepared by prepolymer method followed by emulsion polymerization in aqueous medium. The characterization of dispersions was performed by Fourier transform infrared, dynamic light scattering, atomic force microscopy, differential scanning calorimetry, and thermogravimetric analysis. In general, aliphatic hard segment has shown more appreciable results. But, thermal stability of aromatic polyurethane acrylate was more pronounced as inherent rigidity of aromatic diisocyanate dominates.     

Silanization of ZnO nanofibers by tetraethoxysilane

Zinc oxide (ZnO) nanofibers are synthesized by electrospinning technique and then silanized to tailor its structural, optical, and electrical properties. The modification of ZnO nanofibers by chemical treatment of tetraethoxysilane (TEOS) is clearly evident from the appearance of relevant Fourier transform infrared peak at about 1000 cm^?1 corresponding to Zn? O? Si bond. The height of this peak increases linearly with increase in concentration of silane up to 400 μL, and afterward become plateau up to 500 μL. Diffuse reflectance spectroscopy measurement shows that band gap decreases from 3.35 eV for pure zinc oxide nanofibers to 3.11 eV with successive increase in concentration of TEOS from 100 to 500 μL. The electrical characteristics of modified ZnO nanofibers are analyzed by impedance spectroscopy. It is observed that impedance of ZnO nanofibers increases (resistance from 1.69 × 10⁸ to 2.618 × 10⁹ ohm and capacitance from 2.043 × 10^?12 to 7.618 × 10^?13 F) with increase of TEOS concentration. This study provides guidelines for tailoring the electrical properties of ZnO nanofibers. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134 , 45378.     

Effect of oxidation and esterification on functional properties of mung bean (Vigna radiata (L.) Wilczek) starch

The chemical and physicochemical properties of mung bean starch oxidized by sodium hypochlorite and esterified with succinic anhydride were studied. Mung bean starch was modified by oxidation with sodium hypochlorite and esterified with succinic anhydride. The native mung bean starch (NMBS) granules were shown to have an irregular shape, which varied from oval to round to bean shape with a smooth surface. Succinylation led to partial rupture of the granule integrity while oxidation converted the smooth surface of the native granules to a surface with fissures. Swelling capacity improved through succinylation but was reduced after oxidation. Oxidation enhanced solubility; however, succinylation showed no uniform effect throughout the temperature range studied. Both modifications increased hydrophilic tendency and demonstrated decreased gelatinization temperature compared to the NMBS. Oil absorption capacity and syneresis of native starch was enhanced after oxidation but was reduced after succinylation. Both starch types, native and modified, exhibited non-Newtonian behavior, but to a different extent. The gel formation of oxidized starch revealed the highest storage modulus followed by native starch and then succinated starch.