Effects of space velocity on methanol synthesis from Co2/Co/H2 over Cu/ZnO/Al2O3 catalyst

The space velocity had profound and complicated effects on methanol synthesis from CO₂/CO/H₂ over Cu/ZnO/Al₂O₃ at 523 K and 3.0MPa. At high space velocities, methanol yields as well as the rate of methanol production increased continuously with increasing CO₂ concentration in the feed. Below a certain space velocity, methanol yields and reaction rates showed a maximum at CO₂ concentration of 5–10%. Different coverages of surface reaction intermediates on copper appeared to be responsible for this phenomenon. The space velocity that gave the maximal rate of methanol production also depended on the feed composition. Higher space velocity yielded higher rates for CO₂/ H₂ and the opposite effect was observed for the CO/H₂ feed. For CO₂/CO/H₂ feed, an optimal space velocity existed for obtaining the maximal rate.     

Point Defects in CdZnTe Crystals Grown by Different Techniques

We studied, by current deep-level transient spectroscopy (I-DLTS), point defects in CdZnTe detectors grown by different techniques. We identified 12 different traps with energy levels from 7 meV to 1.1 eV. Although the levels of most of the identified defects were independent of the crystal growth techniques, nevertheless there were some associated differences in the traps’ energies and densities.     

Changes in total phenols, total flavonoids, and antioxidant activities of common beans and pinto beans after soaking, cooking, and in vitro digestion process

Even though bean varieties are widely consumed all over the world, data related to how cooking methods and in vitro digestion affect bioactive compounds they contain and data related to bioavailability of polyphenols are limited. The aim of the present study was to investigate how some cooking methods and in vitro digestion influence antioxidant activity, total phenols (TP), and total flavonoids (TF) of widely consumed beans in Turkey. Soaking caused a significant decrease (25.61–38.63%) in the bioavailability of TP of dry common beans (CB). Soaking in cold water resulted in a significant decrease in TP bioavailability of dry pinto beans (PB). TF content was well retained in PB cooked without soaking but was not detected in CB after in vitro digestion. CB soaked in hot water and cooked with the addition of NaHCO₃ showed the greatest inhibition effect on 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical (p<0.05). In vitro digestion caused increase in the antioxidant activity of both CB and PB.     

Catalytic fluorination of HCFC-133a (1,1,1-trifluoro-2-chloroethane)

Catalytic fluorination of HCFC-133a was performed over metal oxide catalysts. Chromium oxide showed the best catalytic activity among several metal oxides tested. An increase in the crystallinity with decreased surface area resulted in a decrease of catalytic activity for the fluorination reaction. Active phase of chromia is Cr-O-F-OH having a proper ratio of O/F and a high hydroxyl content. The hydroxyl content on the catalyst is strongly dependent on support material. The selectivity to HFC-134a is independent of the O/F ratio on the Cr surface.     

Postponement growth and antioxidative response of Brassica nigra on CuO and ZnO nanoparticles exposure under soil conditions

Due to unique physiochemical properties, nanoparticles (NPs) have acquired substantial attention in the field of research. However, threats of ecotoxicity and phytotoxicity have limited their biological applications. In this study in vivo experiments were performed to determine the effect of CuO (12.5, 25 and 50 mg/kg) and ZnO (200, 400 and 600 mg/kg) NPs on growth, and antioxidant activities of Brassica nigra. The results showed that CuO NPs did not affect the seed germination while presence of ZnO NPs in the soil generated an inhibitory effect. Both CuO and ZnO NPs positively influenced the growth of stem and other physiological parameters i.e. stem height increased (23%) at 50 mg/kg CuO while root length decreased (up to 44%) with an increase in the concentration of NPs. Phytochemical screening of apical, middle and basal leaves showed elevated phenolic and flavonoid contents in the range of 15.3–59 μg Gallic Acid Equivalent (GAE)/mg Dry Weight (DW) and 10–35 μg Querceitin Equivalent (QE)/mg DW, respectively, in NPs‐treated plants. Antioxidant activity was higher in CuO NPs‐treated plants as compared to ZnO and control plants. Results conclude that CuO and ZnO NPs at low concentrations can be exploited as nanofertilisers in agriculture fields.Inspec keywords: biochemistry, enzymes, renewable materials, crops, nanoparticles, soil, nanofabrication, zinc compounds, organic compounds, agricultural products, toxicology, nanobiotechnologyOther keywords: antioxidative response, ZnO nanoparticles exposure, soil conditions, unique physiochemical properties, germination, antioxidant activities, brassica nigra plant, antioxidant activity, CuO NP‐treated plants, control plants, ZnO NPs effect, mass 15.3 mug to 59.0 mug, mass 10.0 mug to 35.0 mug, CuO, ZnO     

Transformation and intensification of tornado-like flow in a narrow channel during elongation of an oval dimple with constant area

Technical Physics Letters - Reynolds averaged Navier–Stokes equations closed using the Menter shear-stress-transfer model have been numerically solved on multiblock intersecting structured...     

Electronic and geometric effects of alkali promoters in CO hydrogenation over K/Mo2C catalysts

When potassium salts such as K₂CO₃, KOH, CH₃COOK, and K₂S were added to Mo₂C, the promoted catalysts showed high selectivities to alcohols and light olefins in CO hydrogenation at 573 K and 1.0 MPa. However, K₂SO₄ and KCl caused only slight increase in olefin selectivity with negligible alcohol formation. These two groups of promoters showed different physical and chemical states during the reaction as observed by AES, EDS, EPMA, IR and transient reaction behavior. This difference accounted for the observed difference in selectivity.     

The effect of chemical reaction on effective deffusivity within biporous catalysts—II: Experimental study

An experimental method was developed to study the adsorption and diffusion of the reactant, and the product, reacting on porous catalysts by simultaneoTo study the effect of reaction on the effective diffusivity, supporting experiments were performed to obtain precise adsorption and diffusion characteThree types of zeolite catalysts, LiY, NaY, both active and KY, inactive, were prepared and were used to catalyze the isomerization reaction of cycloprEquilibrium adsorption constants and diffusivities measured under nonreactive conditions were comparable to values found in literature. For inactive caTherefore the use of effective diffusivity value obtained in nonreactive condition to estimate effectiveness factor may give significantly erroneous re