Structural and electrical properties of brush plated ZnTe films

Zinc telluride thin films were deposited by the brush plating technique at a potential of −0.90 V (SCE) on conducting glass and titanium substrates at different temperatures in the range 30–90 °C. The films were polycrystalline in nature with peaks corresponding to the cubic phase. Direct band gap of 2.30 eV was observed. XPS studiers indicated the formation of ZnTe. Depth profiling studies indicated a uniform distribution of Zn and Te throughout the entire thickness. EDAX measurements were made on the films and it was found that there was a slight excess of Te. The carrier concentration was found to vary from 10¹⁴–10¹⁵ cm⁻³ with increase of substrate temperature. The mobility was found to vary from 5 to 60 cm² V⁻¹ s⁻¹.     

Mesoporous titanium dioxide nanocatalyst: a recyclable approach for one‐pot synthesis of 5‐hydroxymethylfurfural

The present study deals with the production of 5‐hydroxymethyl furfural (HMF) from fructose by chemo‐conversion method using chemical catalyst, conventionally achieved by microwave‐assisted dehydration process. Five different chemical catalysts, namely oxalic acid, phosphotungstic acid and mesoporous titanium dioxide nanoparticles (TNPs) were compared at constant conditions of which TNPs yielded a maxima of 33.95%. The optimum temperature and catalyst loading were found to be 200°C and 20%, respectively, at a 5% optimum substrate concentration during 15 min optimum reaction time to yield 61.53% HMF. The efficiency of synthesised TNPs was investigated further through reusability studies. TNPs were properly recycled and the catalytic activity recovery was good even after a 14 batch reactions. The specific surface area of the TNP obtained is about 105.46 m² /g and its pore‐volume is about 0.42 cm³ /g according to single point adsorption. A large accessible surface area combined with a minimal pore size (15.92 nm) obtained with mesoporous TNPs is desirable for better catalyst loading, high‐yield HMF, retention and reduced diffusion constraints.Inspec keywords: mesoporous materials, recycling, production management, dissociation, nanoparticles, nanotechnologyOther keywords: mesoporous titanium dioxide nanocatalyst, recyclable approach, one‐pot synthesis, 5‐hydroxymethyl furfural production, HMF, chemo‐conversion method, chemical catalyst, microwave‐assisted dehydration process, oxalic acid, phosphotungstic acid, mesoporous titanium dioxide nanoparticles, TNP     

Scaling study of cavitation pitting from cavitating jets and ultrasonic horns

Cavitation erosion prediction and characterization of cavitation field strength are of interest to industries suffering from cavitation erosion detrimental effects. One means to evaluate cavitation fields and materials is to examine pitting rates during the incubation period, where the test sample undergoes localized permanent deformations shaped as individual pits. In this study, samples from three metallic materials, an Aluminum alloy (Al 7075), a Nickel Aluminum Bronze (NAB) and a Duplex Stainless Steel (SS A2205) were subjected to a vast range of cavitation intensities generated by cavitating jets at different driving pressures and by an ultrasonic horn. The resulting pitted sample surfaces were examined and characterized with a non-contact 3D optical scanner and the resulting damage computer-analyzed. A statistical analysis of the pit population and its characteristics was then carried out. It was found that the various cavitation field strengths can be correlated to the measured pit distributions and that two characteristic quantities: a characteristic number of pits per unit surface area and unit time, and a characteristic pit diameter or a characteristic pit depth can be attributed to a given “cavitation intensity level”. This characterization concept can be used in the future to study the cavitation intensity of the full scale and to develop methods of full scale predictions based on model scale erosion data.     

Synthesis,Biochemistry, and Computational Studies of Brominated Thienyl Chalcones: A New Class of Reversible MAO‐B Inhibitors

A series of (2E)‐1‐(5‐bromothiophen‐2‐yl)‐3‐(para‐substituted phenyl)prop‐2‐en‐1‐ones ( TB1 – TB11 ) was synthesized and tested for inhibitory activity toward human monoamine oxidase (hMAO). All compounds were found to be competitive, selective, and reversible toward hMAO‐B except (2E)‐1‐(5‐bromothiophen‐2‐yl)‐3‐(4‐nitrophenyl)prop‐2‐en‐1‐one ( TB7 ) and (2E)‐1‐(5‐bromothiophen‐2‐yl)‐3‐(4‐chlorophenyl)prop‐2‐en‐1‐one ( TB8 ), which were selective inhibitors of hMAO‐A. The most potent compound, (2E)‐1‐(5‐bromothiophen‐2‐yl)‐3‐[4‐(dimethylamino)phenyl]prop‐2‐en‐1‐one ( TB5 ), showed the best inhibitory activity and higher selectivity toward hMAO‐B, with K_i and SI values of 0.11±0.01 μm and 13.18, respectively. PAMPA assays for all compounds were carried out in order to evaluate the capacity of the compounds to cross the blood–brain barrier. Moreover, the most potent MAO‐B inhibitor, TB5 , was found to be nontoxic at 5 and 25 μm , with 95.75 and 84.59 % viability among cells, respectively. Molecular docking simulations were carried out to understand the crucial interactions responsible for selectivity and potency.     

Microwave-assisted synthesis and characterization of tin oxide nanoparticles

Tin oxide nanoplatelets (SnO) and nanoparticles (SnO₂) were prepared by microwave assisted technique with an operating frequency of 2.45 GHz. This technique permits to produce gram quantity of homogeneous nanoparticles in just 10 min. The crystalline size was evaluated from XRD and found to range from 26 to 34 nm. SEM and TEM analyses showed that the nanoparticles present a platelet-like shaped particle or, a pseudo spherical morphology, after calcination at moderate temperature during which the phase transformation from SnO to SnO₂ takes place. Additional FT-IR, density and resistivity measurements were also presented.     

Chronic growth faltering amongst a birth cohort of Indian children begins prior to weaning and is highly prevalent at three years of age

Background  

Poor growth of children in developing countries is a major public health problem associated with mortality, morbidity and developmental delay. We describe growth up to three years of age and investigate factors related to stunting (low height-for-age) at three years of age in a birth cohort from an urban slum.     

A new class of Sol–gel derived LiM1xM2yMn2?x?yO3.8F0.2 (M1?=?Cr, M2?=?V; x?=?y?=?0.2) cathodes for lithium batteries

A series of LiM_1xM_2yMn_2−x−yO_3.8F_0.2 (M₁ = Cr, M₂ = V; x = y = 0.2) cathodes, viz., LiMn₂O_3.8F_0.2, LiCr_0.2Mn_1.8O_3.8F_0.2 and LiCr_0.2V_0.2Mn_1.6O_3.8F_0.2 along with native LiMn₂O₄ have been synthesized by Citric Acid assisted Modified (CAM) sol–gel method, with a view to understand the effect of synthesis methodology and the effect of dual category dopants, viz., anion and/or cation upon spinel cathodes individually. An acceptable capacity retention (94%) observed up to 50 cycles for native LiMn₂O₄ cathodes is attributed to the significance of CAM sol–gel method. Similarly, the encouraging charge–discharge results of LiMn₂O_3.8F_0.2 (130 mAh g⁻¹) and LiCr_0.2Mn_1.8O_3.8F_0.2 (142 mAh g⁻¹) cathodes revealed a possible augmentation in the reversible capacity behavior of the spinels upon F⁻ substitution at 32e site and the simultaneous substitution of Cr³⁺ and F⁻ at 16d and 32e sites respectively.     

An investigation on the mechanism of droplet formation in a microfluidic T-junction

This paper reports the findings of a numerical investigation on the droplet break-up in a microfluidic T-junction. The numerical flow visualization of the droplet formation process is validated with the experimental flow visualization. From the computational results, we show that the pressure profile of the dispersed phase and the continuous phase in the squeezing regime changes as the droplet break-up process proceeds. The assumption taken by other researchers that the dispersed phase pressure profile, during the droplet formation process at a T-junction, remains constant and only the continuous phase pressure changes according to the blockage of the channel is proved to be invalid. We provide new insights on the pressure difference between the dispersed phase and the continuous phase during the droplet break-up process and show that the minimum pressure difference happens at the last moment of the droplet break-up and not during the second and third stage of the droplet formation mechanism in the squeezing regime as suggested by other researchers.