The preparation of hard and super‐hydrophilic MgB2 coating by spray pyrolysis deposition

In this study, we report spray pyrolysis deposition using an alternative precursor solution for the fabrication of MgB₂ films. Polycrystalline MgB₂ films were prepared by spray pyrolysis, a precursor solution of magnesium diboride nanoparticles, sodium hypophosphite, sodium succinate, sodium acetate and dimethyl sulfoxide on AZ91 magnesium alloys. The spray was carried out using argon as carrier gas at a temperature of 150 °C and a spray rate of 5 ml/min for 60 min. After spraying, the deposited samples were annealed at 300 °C for 15, 30 and 45 min in order to investigate morphological changes and crystallization behaviour. The microstructure, hardness and wettability properties of approximately 30 μm coatings were investigated by X‐ray diffraction, scanning electron microscopy, microhardness tester and contact angle meter. Produced coatings showed dense and homogenous structural formation with strong grain connections. As‐deposited MgB₂ films showed the most pronounced preferred orientation with the (101) reflection and the highest hardness value compared to other annealed coatings at different times. Besides, all the synthesized coatings had a super‐hydrophilic surface.     

Energy consumption and economic growth in the USA: Evidence from renewable energy

Recent debates about renewable energy consumption manifest two main expectations. Firstly, renewable energy consumption should contribute to economic growth and secondly, it should not cause damage on environment. This study focuses on the first issue by applying Toda–Yamamoto procedure and bootstrap-corrected causality test for the US since empirical literature criticizes the Toda–Yamamoto test which bases on asymptotic distribution. The models consist of real GDP, employment, investment and kinds of renewable energy consumption. Only one causal relationship was found from biomass-waste-derived energy consumption to real GDP. No causal relationship was found between real GDP and all of the other renewable energy kinds—total renewable energy consumption, geothermal energy consumption, hydro-electric energy consumption, biomass energy consumption and biomass-wood-derived energy consumption. That is using of energy from waste cause not only solving the dumping problems but also it contributes to real GDP. For policy purpose, the results of this study suggest that countries should concentrate on energy producing from waste as an alternative energy resource.     

New metal alkoxides: Synthesis and hydrolysis-condensation reactions; some adsorption features of the hydrolysis-condensation products

In this work, (a) hydrolyses of Ti(OEt)₄ and Zr(OPrⁿ)₄ with different amounts of water, (b) complexation of the same alkoxides with varying amounts of methacrylic acid, (c) hydrolysis of the complexation products with varying amounts of water, and subsequent polymerization, (d) adsorption capacities of the hydrolysis products (a and c) for aqueous aniline and phenol, were investigated. It was found that condensation reactions which follows the hydrolysis reactions, were alcohol condensations. The products were characterized in detail. Adsorption of aniline and phenol were compared for thermally conditioned powder of the products and some powders coated with 3-glycidyloxypropyltrimethoxysilane. It was observed that the extent of adsorption was influenced significantly by the temperature at which the adsorbents were calcinated by the coating of their surfaces.     

Communication over Hypercomplex Kähler Manifolds: Capacity of Multidimensional-MIMO Channels

We consider the single-user communications scenario over joint space, pattern and polarization diversity providing dual-polarized multidimensional-MIMO (PMD-MIMO) channels established by the use of multiple dual-polarized transmit/receive antennas in the form of uniformly-spaced 1D, 2D and/or 3D MIMO arrays. Based on the equivalent channel-models formulated on hypercomplex manifolds, we subsequently identify the decomposition of dual-polarized PMD-MIMO channels into multiple independently-fading and attenuated classical MIMO channels in parallel through the algebraic properties of hypercomplex Kähler manifolds and consequently derive the corresponding ergodic capacities analytically. We show in essence via the diversity-reception over independent channels perspective deduction of the decomposition into parallel MIMO channels observation that the capacity gains achievable by PMD-MIMO Tx/Rx over classical single-polarized linear antenna array MIMO Tx/Rx may be notably large with equal number of transmit and/or receive antenna locuses and under same resource requirements/channel conditions whenever the cross-polar discrimination between dual antennas is good.     

3D numerical modeling of longwall mining with top-coal caving

There is a considerable amount of lignite reserve in the form of thick seams in Turkey. It is rather complicated to predict the characteristics of strata response to mining operation in thick seams. However, a comprehensive evaluation of ground behavior is a prerequisite for maintaining efficient production, especially when the top-coal-caving method behind the face is applied. Top-coal caving is the key factor affecting the efficiency of production at thick-coal seams. During production of top coal by caving behind the face not only a significant amount of coal is lost in the goaf but the coal drawn by means of caving is diluted considerably with surrounding rock. Therefore, it is not possible to carry out an efficient production operation unless caving of top coal behind the face is optimized. In this paper, results of 3D modeling of the top-coal-caving mechanism by using the finite difference code FLAC^3D at the M3 longwall panel of the Omerler Underground Mine located at Tuncbilek (Turkey) are presented. According to the modeling results, maximum vertical abutment stresses were formed at a distance of 7 m in front of the face. An analysis of the conditions of top coal has revealed that a 1.5 m thick layer of coal just above the shield supports is well fractured. However, a 3.5 m thick layer of coal above the fractured part is either not fractured or is fractured in the form of large blocks leading to obstruction of windows of shields during coal drawing. It is concluded that, in order to decrease dilution and increase extraction ratio and efficiency of operation, top coal should be as uniformly fractured as possible. Hence, an efficient and continuous coal flowing behind the face can be maintained. A special pre-fracture blasting strategy just sufficient enough to form cracks in the top coal is suggested by means of comparing with the results of numerical modeling.     

Characterization of the hydrothermally synthesized nano-TiO2 crystallite and the photocatalytic degradation of Rhodamine B

Pure anatase-TiO2 nanoparticles with 8 nm average crystallite size was synthesized hydrothermally at 200 degrees C in 2 h. The structural and physico-chemical properties of nano-TiO2 were determined by powder XRD, FT-IR, BET and SEM analyses. The behavior of anatase nano-TiO2 in catalytic degradation of Rhodamine B (RB) dye in transparent nano-TiO2 sol under UV-light was examined as a function of irradiation power of UV-light, irradiation time, amount of nano-TiO2 and initial RB concentration in the sol. Rhodamine B was fully degraded with the catalysis of the nano-TiO2 in a short time as low as 60 min. Photocatalytic activity of the nano-TiO2 for degradation of RB was compared with Degussa P-25 at optimum catalysis conditions determined for the nano-TiO2. It was found that, when compared to Degussa P-25, the nano-TiO2 could be repeatedly used with increasing photocatalytic activity. It was found that the photodegradation obeys the pseudo first-order reaction kinetics with the rate constant of 0.0658 min(-1), and the half period t1/2 was 10.53 min.     

Microbiological and physicochemical properties of farm bulk tank milk and antimicrobial resistance of its dominant bacteria

This study determined the antibiotic resistance of the dominant bacteria in the 85 farm BTMs according to the guidelines recommended by the epidemiological cutoff values in the EUCAST. In addition, some physicochemical and microbiological properties of farm BTMs were investigated. The milk samples were divided into two groups according to their SCC values. The milk samples with higher SCC than 400,000 cells mL⁻¹ were further examined bacteriologically, and the antibiotic resistance of isolates was determined. The average TAMB value was 6.34 log CFU/mL in farm BTM. It was found that high-SCC values did not affect other physicochemical properties of BTM samples, such as fat, protein and total solids, except for lactose content. Seventy-two strains were isolated from 45 bulk milk samples. The most prevalent bacteria were Enterococcus spp. (23.61%). The other isolates were Citrobacter spp. (12.5%), Staphylococcus spp. (12.51%), Serratia spp. (11.12%), Klebsiella spp. (9.72%), Bacillus spp. (9.72%), and Enterobacter spp. (8.33%). In antibiotic resistance analysis, 52.6% of Enterobacterales isolates showed cefoxitin resistance, and nine Enterobacterales isolates were determined as the presumptive ESBL producers. None of them was confirmed as ESBL producers. Moreover, MDR was detected in 83.3% of Enterobacter spp. isolates and all Bacillus spp. isolates. The over and inappropriate use of antibiotics in mastitis treatment may cause antibiotic-resistant microorganisms in milk. It was found that 52.7% of the isolated bacteria were MDR, which could pose a risk to public health and food safety, with the consumer's increasing interest in consuming raw milk.