Salicylaldimine-Ni complex supported on Al2O3: Highly efficient catalyst for hydrogen production from hydrolysis of sodium borohydride

In this study, the Ni-based complex catalyst containing nickel of 1% supported on Al₂O₃ is used as for the hydrogen production from NaBH₄ hydrolysis. The maximum hydrogen production rate from hydrolysis of NaBH₄ with Ni-based complex catalyst supported on Al₂O₃ containing nickel of 1% is 62535 ml min^?1 g^?1 (complex catalyst containing 1 wt% Ni). The resulting complex catalyst is characterised by XRD, XPS, SEM, FT-IR, UV, and BET surface area analyses. The Arrhenius activation energy is found to be 27.29 kJ mol^?1 for the nickel-based complex catalyst supported on Al₂O₃. The reusability of the catalyst used in this study has also been investigated. The Ni-based complex catalyst supported on Al₂O₃ containing nickel of 1% is maintained the activity of 100% after the fifth use, compared to the first catalytic use. The n value for the reaction rate order of NaBH₄ is found to be about 0.33.     

Preparation of N‐doped graphene‐based electrode via electrochemical method and its application in vanadium redox flow battery

An N‐doped graphene electrode has been prepared by cyclic voltammetric method in 5.0 M of HNO₃ solution on a graphite‐based electrode at room temperature. The modification of the electrode surface with different types of N‐containing groups, such as nitro groups, pyrrolic N, and pyridinic N, has been controlled by changing the scanned potential ranges. The formation of an N‐doped graphene electrode has been confirmed by scanning electron microscopic, atomic force microscopic, X‐ray photoelectron, and Raman spectroscopic methods. The prepared N‐doped graphene‐modified electrodes have been used in positive electrolyte of a vanadium‐based redox flow battery. As positive electrodes, the electrochemically modified electrodes prepared in 5.0 M of HNO₃ solution ?1.0 to (+1.9) and ?0.7 to (+1.9) V had more than 140 and 120 mA/cm² anodic and cathodic peak currents, respectively, in vanadium redox battery. This fast, low‐cost, and environmentally friendly method can be used in many application areas, such as optical devices, (bio)sensors, energy storage materials, and electronic devices.     

Electrical resistivity of porcelain bodies with natural zeolite addition

In this study, the effect of natural zeolite addition on the electrical properties of porcelain bodies was investigated. Clinoptilolite, which is a type of natural zeolite, was added partially or fully in replacement of quartz in selected electro-porcelain compositions. Samples were fired in an electric furnace with a heating rate of 10 °C/min at 1200 and 1250 °C with a period of 60 min. The electrical resistance measurements of samples were performed at 50, 200, 400 and 600 °C. It was shown that the resistivity of samples increased at 50 °C temperature after zeolite addition, while it was decreasing after zeolite addition at higher temperatures. At the same time, it was recognized that the resistivity of samples depends on sintering temperature. The activation energy of electrical resistivity of samples was found to be in the range of 0.79–0.87 eV.     

A radiointerferometric terminal of the Badary observatory

A radiointerferometric terminal recording signals on hard magnetic disks in the VSI-H format with a rate of up to 1024 Mbit/s is put into operation for the first time in Russia at the Badary observatory. This ensures the possibility of very-long-base radiointerferometry (VLBI) in quasi-real time. A P1000 signal conversion system containing 14 two-band video converters and a 16-channel 2-bit signal digitizing unit with a record-synchronizing device is designed for this terminal at the Institute of Applied Astronomy, Russian Academy of Sciences, and ZAO Radio-Electronic Processing Equipment. The signals are recorded by a Mark 5B recording equipment. The central computer of the radio telescope controls the terminal. Under the international and domestic programs, routine VLBI observations are conducted by the designed terminal in the Badary observatory.     

Selection of optimum cutting condition of cobalt-based superalloy with GONNS

Machining of new superalloys is challenging. Automated software environments for determining the optimal cutting conditions after reviewing a set of experimental results are very beneficial to obtain the desired surface quality and to use the machine tools effectively. The genetically optimized neural network system (GONNS) is proposed for the selection of optimal cutting conditions from the experimental data with minimal operator involvement. Genetic algorithm (GA) obtains the optimal operational condition by using the neural networks. A feed-forward backpropagation-type neural network was trained to represent the relationship between surface roughness, cutting force, and machining parameters of face-milling operation. Training data were collected at the symmetric and asymmetric milling operations by using different cutting speeds (V _c), feed rates (f), and depth of cuts (a _p) without using coolant. The surface roughness (Ra_asymt, Ra_symt) and cutting force (Fx_asymt, Fy_asymt, Fz_asymt, Fx_symt, Fy_symt, Fz_symt) were measured for each cutting condition. The surface roughness estimation accuracy of the neural network was better for the asymmetric milling operation with 0.4% and 5% for training and testing data, respectively. For the symmetric milling operations, slightly higher estimation errors were observed around 0.5% and 7% for the training and testing. One parameter was optimized by using the GONNS while all the other parameters, including the cutting forces and the surface roughness, were kept in the desired range.     

Thermal conductivity of oriental beech impregnated with fire retardant

This study aims to describe the effects of wood material (oriental beech) impregnated with ammonium sulfate, borax, boric acid, and zinc chloride by using two different methods (pressure and dipping) and finishes with the effects of different varnishes (polyurethane, cellulosic, synthetic) and paints (cellulosic, synthetic, industrial) on thermal conductivity. These materials were used as fire retardants. The lowest thermal conductivity of 0.143 kcal/m h°C was obtained in oriental beech control samples. The highest thermal conductivity of 0.172 kcal/m h°C was obtained in oriental beech impregnated with ammonium sulfate by using pressure and varnished with synthetic varnish. Consequently, wood impregnated with ammonium sulfate by using pressure and finished with synthetic varnish can be used as a construction material where thermal conductivity is required. Wood impregnated with borax by dipping and finished with cellulosic varnish can be used as a construction material where the insulation is required.     

Formation of surface layers in leaching of borosilicate glasses incorporating different amounts of simulated HLW

Borosilicate glass specimens incorporating 10, 15, and 20 wt % simulated high-level waste (HLW) were leached at 20, 90, and 120°C in deionized water following the procedure accepted in Russia, GOST (State Standard) R 52 126-2003. At 90°C, the altered surface layer is formed already from the first days of leaching. The main interaction in the system occurs at the phase boundary between the altered surface layer and water, rather than at the phase boundary between the glass and water through the porous surface layer as it is commonly believed. The altered surface layer acts as a natural barrier preventing transfer of simulated waste components to the liquid phase. The barrier properties of the altered surface layer are manifested to the greatest extent at 20 wt % content of simulated HLW in the initial glass and leaching temperature of 120°C.     

Assessment of antiradical potential of Calluna vulgaris (L.) Hull and its major flavonoid

BACKGROUND: Antioxidant capacity of the chloroform, ethyl acetate, n‐butanol and water fractions of the aerial parts of Calluna vulgaris (L.) Hull (Ericaceae) has been assessed in this study. Antioxidant capacity of the plant was screened by assays of 2,2‐diphenyl‐β‐picrylhydrazyl, superoxide anion and hydrogen peroxide scavenging, metal‐chelating activity and reducing power. Butylated hydroxyanisole was used as reference in all assays; ethylene diamine tetraacetic acid was also used as reference in the assay of metal‐chelating activity. Total phenolic contents of the fractions were determined by the Folin–Ciocalteu method. RESULTS: Liquid chromatography/diode array detection/mass spectrometry was used for phytochemical identification of the fractions. Kaempferol‐3‐O‐β‐D ‐galactoside was found to be the major constituent in the ethyl acetate fraction (37.1 ± 0.9%), followed by the n‐butanol fraction (4.6 ± 0.1%). High occurrence of antioxidant capacity, with the exception of metal‐chelating activity, was observed in the ethyl acetate and chloroform fractions as well as in kaempferol‐3‐O‐β‐D ‐galactoside. CONCLUSION: Calluna vulgaris and its major flavonoid, kaempferol‐3‐O‐β‐D ‐galactoside, show high antioxidant capacity in various assays. As far as is known, this is the first report on antioxidant capacity of C. vulgaris and its major flavonoid. Copyright © 2009 Society of Chemical Industry