Tungsten(VI) oxide supported rhodium nanoparticles: Highly active catalysts in hydrogen generation from ammonia borane

Herein, we report the use of tungsten(VI) oxide (WO₃) as support for Rh⁰ nanoparticles. The resulting Rh⁰/WO₃ nanoparticles are highly active and stable catalysts in H₂ generation from the hydrolysis of ammonia borane (AB). We present the results of our investigation on the particle size distribution, catalytic activity and stability of Rh⁰/WO₃ catalysts with 0.5%, 1.0%, 2.0% wt. Rh loadings in the hydrolysis reaction. The results reveal that Rh⁰/WO₃ (0.5% wt. Rh) is very promising catalyst providing a turnover frequency of 749 min^?1 in releasing 3.0 equivalent H₂ per mole of AB from the hydrolysis at 25.0 °C. The high catalytic activity of Rh⁰/WO₃ catalyst is attributed to the reducible nature of support. The report covers the results of kinetics study as well as comparative investigation of activity, recyclability, and reusability of colloidal(0) nanoparticles and Rh⁰/WO₃ (0.5 % wt. Rh) catalyst in the hydrolysis reaction.     

Ionic liquid intercalated clay nanofillers for chromatographic applications

In this study, the preparation and characterization of ionic liquid (IL) intercalated montmorillonite (MMT) and their application as a micro-solid phase extraction material for the determination of Chlorpyrifos (CP) pesticide in water samples were reported. The ionic liquids bearing different chain lengths [1-methyl-3-octylimidazolium bromide (C₈mimBr), 1-methyl-3-undecyl-imidazolium bromide (C₁₂mimBr) and 1-methyl-3-octadecyl-imidazolium bromide (C₁₈mimBr)] were intercalated in the galleries of MMT. The IL-intercalated MMTs were characterized by means of XRD and TG methods. The (C₁₂mimBr)-intercalated MMT had the highest sorption efficiency for the CP, which was 32 times higher than the original MMT. We also optimized the parameters for extracting CP from the (C₁₂mimBr)-intercalated MMT.     

An experimental investigation on the low velocity impact response of composite plates repaired by VARIM and hand lay-up processes

This paper presents results of an experimental investigation on the impact response of repaired and unrepaired glass/epoxy composite plates. Repaired samples were prepared by two different manufacturing methods; vacuum assisted resin infusion process and hand lay-up technique. In order to compare impact response of the repaired and unrepaired samples a number of single impact tests were performed under various impact energies. Damage process of the samples is analyzed from cross-examining load–deflection curves and damaged specimens. From the visual inspection, for the impacted side of the samples, it is noted that the main damage modes for repaired samples are matrix and fiber cracks around point of impact and delaminations while severe matrix cracks expanded through fiber directions are the dominant damage mode for unrepaired samples. At the back surfaces, delaminations and fiber–matrix debonding oriented in the fiber directions are observed for unrepaired samples. However, for repaired samples the fiber fractures through repair line as well as the delaminations become dominant modes. For a reasoning justification in discussing impact test results, interlaminar fracture toughness (Mode I and Mode II) and flexural tests for repaired and non-repaired samples were also conducted.     

Moisture Dependent Physical Properties of Dry Sweet Corn Kernels

Physical properties of sweet corn kernels have been evaluated as a function of kernel moisture content, varying from 9.12 to 17.06% (db). In the moisture range, kernel length, width, thickness, and geometric mean diameter increased linearly from 9.87 to11.09 mm, 7.41 to 9.25 mm, 3.25 to 4.37 mm, and 6.18 to 7.62 mm, respectively, with increase in moisture content from 9.12–17.06%. The sphericity index, kernel volume, kernel surface area, and thousand seed weight increased linearly from 62.6 to 68.8, 93.8 to 194.3 mm³, 120.1 to 182.9 mm², and 220 to 268 gr, respectively. Apparent density and bulk density decreased linearly from 1.315 to 1.232 g/cm³ and 0.765 to 0.698 g/cm³, respectively, while bulk porosity increased from 41.8 to 43.3%. The highest static coefficient of friction was found on the plywood surface. The static coefficient of friction increased from 0.680 to 0.891, 0.605 to 0.741, and 0.530 to 0.644 for plywood, galvanized iron, and aluminum surfaces, respectively. The angle of repose increased linearly from 30.2 to 35.2° with the increase of moisture content.