Hydrogen production by methanol steam reforming on a cordierite monolith reactor coated with Cu–Ni/LaZnAlO<Subscript>4</Subscript> and Cu–Ni/γ-Al<Subscript>2</Subscript>O<Subscript>3</Subscript> catalysts

The performance of Cu–Ni/LaZnAlO₄ and Cu–Ni/γ-Al₂O₃ catalysts in the methanol reforming process in a monolith reactor in the temperature range of 200–350 °C, feed flow rate of WHSV = 20.8 h^?1 and atmospheric pressure has been investigated. In order to perform a more thorough investigation, surface area, morphology and crystalline structure of the synthetic catalysts have been studied using BET, FE-SEM, TPR, FT-IR, TEM, TGA and XRD analyses. The results have shown that Cu–Ni/LaZnAlO₄ catalyst synthesized by combustion reaction method under ultrasound irradiation has a very high efficiency and catalytic activity, low reduction temperature, high mechanical resistance and large pore sizes. The latter causes a higher percentage of active metal impregnation and better distribution on the support, greater resistance against sintering and maintenance of catalyst inertness at temperatures over 1000 °C, in comparison with conventional catalysts such as Cu–Ni/γ-Al₂O₃. This make its substitution for currently used catalysts affordable.     

Effective eddy viscosity in stratified turbulence

This paper investigates the effective eddy viscosity inferred from direct numerical simulations of decaying stratified and non-stratified turbulence. It is shown that stratification affects the horizontal eddy viscosity dramatically, by increasing non-local energy transfer between large and small horizontal scales. This non-local horizontal energy transfer is around 20% of the local horizontal energy transfer at the cutoff wavenumber k_c = 40. The non-local horizontal energy transfer occurs at large vertical wavenumbers, which may be larger than the buoyancy wavenumber k_b = N/u_rms, where N is the buoyancy frequency and u_rms is the root-mean-square velocity. By increasing the value of the test cutoff wavenumber k_c from large scales to the dissipation range, the non-local horizontal eddy viscosity decreases and the local eddy viscosity is dominant. Overall, the presence of stratification can significantly change the features of subgrid-scale (SGS) motions. Current SGS models should, therefore, be modified for use in large-eddy simulation of stratified turbulence.     

A correction of (2+1) Dimensional BTZ Black Hole Entropy as a New Series with Dependence on Plank Constant

We investigate the corrected entropy and Hawking temperature of the BTZ black hole which obtained from (2 + 1) dimensional black hole. Besides, we generalize our analysis of black holes to the case of Friedmann-Robertson-Walker (FRW) universe. The corrections to the Hawking temperature and entropy of apparent horizon for FRW universe are also obtained. Comparing the results with the high energy black hole demonstrates how the semi-classic approximation affects the thermodynamics of the BTZ black hole, corrected terms, classical action and the entropy.     

Electroosmotic flow in a water column surrounded by an immiscible liquid

In this paper, we conducted numerical simulation of the electroosmotic flow in a column of an aqueous solution surrounded by an immiscible liquid. While governing equations in this case are the same as that in the electroosmotic flow through a microchannel with solid walls, the main difference is the types of interfacial boundary conditions. The effects of electric double layer (EDL) and surface charge (SC) are considered to apply the most realistic model for the velocity boundary condition at the interface of the two fluids. Effects on the flow field of ?-potential and viscosity ratio of the two fluids were investigated. Similar to the electroosmotic flow in microchannels, an approximately flat velocity profile exists in the aqueous solution. In the immiscible fluid phase, the velocity decreases to zero from the interface toward the immiscible fluid phase. The velocity in both phases increases with ?-potential at the interface of the two fluids. The higher values of ?-potential also increase the slip velocity at the interface of the two fluids. For the same applied electric field and the same ?-potential at the interface of the two fluids, the more viscous immiscible fluid, the slower the system moves. The viscosity of the immiscible fluid phase also affects the flatness of the velocity profile in the aqueous solution.     

Polyethylene-based nanocomposite: Structure and properties of poly(vinyl alcohol)/organofunctionalized Mg-doped fluorapatite hybrid

We report here the production and characterization of polymer nanocomposites (NC)s containing nanoceramics of organofunctionalized Mg-doped fluorapatite (MDFA) in a poly(vinyl alcohol) matrix. First, the MDFA materials were functionalized with N-trimellitylimido-L-leucine modifier through ultrasonic irradiation. The numerous experimental techniques like Fourier transform infrared spectroscopy, X-ray diffraction, atomic force microscopy, field emission scanning electron microscopy, transmission electron microscopy, and thermogravimetric analysis were applied to characterize the prepared materials. Thermal analysis of the obtained NCs showed an increase in thermal stability of the NCs when compared to the neat macromolecule.     

Designing composite polymer electrolytes for all-solid-state lithium batteries

Ceramic fast-ion conductors have high ionic conductivities (>10^?4 S cm^?1) but are difficult to process and have poor chemo/mechanical properties at the electrode/electrolyte interfaces. In contrast, polymer electrolytes are pliable and easy to process but suffer from low room-temperature ionic conductivities (≈10^?6-10^?7 S cm^?1). Combining these two elements to form a composite polymer electrolyte is a promising way to enable all-solid-state lithium-metal batteries. The choice of ceramic filler and polymer can be tailored to provide synergistic benefits that overcome the practical shortcomings of the two components. Herein, the fundamentals of Li⁺ conduction through the various phases and interfaces in these materials are discussed as well as the important parameters, beyond the initial choice of polymer and ceramic filler materials that must be considered while designing composite polymer electrolytes. Emphasis is placed on the particle filler engineering and practical fabrication methods as routes toward enhancing the properties of these composites.     

A new and simple method for sulfur nanoparticles synthesis

Sulfur nanoparticles were successfully synthesized via novel water-in-oil microemulsion system. The microemulsion system contained cyclohexane as an oil phase, Triton X-100 as a surfactant, butanol as a co-surfactant and sodium polysulfide solution or hydrochloric acid solution as aqueous phase, respectively. The sulfur nanoparticles were characterized by X-ray diffraction, scanning electron microscopy, energy dispersive spectroscopy and Fourier transform infrared spectroscopy. The results showed that the as-prepared monoclinic sulfur nanoparticles exhibited high purity and spherical shape with an average size of about 22 nm.     

A reusable reduced graphene oxide-cobalt oxide nanocomposite with excellent yield as adsorbent for determination trace-level of brilliant green in environmental water samples

Research on Chemical Intermediates - In view of large-scale production, usage and toxic nature, the synthetic dyes are a very significant category of pollutants. This work reports the preparation...     

A Sensitive Method for Determination Glycolic Acid, Mono- and Di-Chloroacetic Acids in Betaine Media Using Amino-Functionalized SBA-15 as a Sorbent and HPLC Assay

In this paper, amino-modified nanoporous silica (APS-SBA-15) was synthesized as a new solid-phase sorbent for the extraction of glycolic acid, monochloroacetic acid, and dichloroacetic acid in synthetical betaine products. Octadecyl silica cartridge was used to reduce the concentration of matrix betaine. PS-Ag⁺ pre-treatment cartridge was applied to remove high Cl^? concentration. The obtained effluent sample was passed through of the APS-SBA-15 sorbent. The effect of pH, flow rate of sample and eluent, and type and volume of the eluent were investigated and optimized. Chloroacetate and glycolate were eluted with 0.8 mol L^?1 solution of HClO₄ and measured by HPLC with a UV–vis detector. At optimum effective parameters, preconcentration factor of 129 was achieved in this method. The detection limits of mono- and dichloroacetic acid and glycolic acid were 13, 3.7, and 8.6 ng L^?1, respectively.