Catalytic dehydrogenation of isopropanol on La2−xSrxNiO4±y

The series of compounds La_2–xSr_xNiO_4±y (0.0 x 1.0) crystallising in tetragonal K₂NiF₄ structure were prepared and catalytic activity have been investigated using isopropanol decomposition as model reaction. All the catalyst compositions catalyse only the dehydrogenation of isopropanol reaction. The composition La_1.5Sr_0.5NiO₄ showed high activity compared to other compositions in the series. The composition is unique not only in catalytic property but also in other physical properties like structural characteristics, electrical resistivity and metal to semiconductor transition.     

Microwave drying of CuCl residue from hydrometallurgical zinc recovery process

CuCl residue is a hazardous waste from the hydrometallurgical zinc recovery plant. It is very difficult to recycle due to complicated composition, highly corrosive nature, and refractory characteristics. Recently, a new process of microwave drying and roasting was successfully developed to produce both CuO solid and HCl gas products from the CuCl residue. In this paper, the dielectric property of the CuCl residue was measured under different moisture contents. The microwave absorption characteristics of the CuCl residue improved considerably as its moisture content increased. Laboratory-scale drying tests were conducted to evaluate the kinetics of microwave drying and to optimize the operation parameters. The efficiency of microwave drying was further demonstrated in industrial-scale level by microwave dryer developed in in-house. Finally, the drying mechanism of microwave heating of the sticky material was discussed and several measurements were optimized/implemented to intensify the drying process.     

Calf massager: Intervention for body muscle discomfort during prolonged standing

Many occupations require workers to stand for long periods of time without proper interventions, which causes discomfort in the back and lower limbs. Therefore, this study aims to assess the effectiveness in alleviating body muscle discomfort during prolonged standing through the use of a calf massager. This study was conducted among male workers at a manufacturer with production line workers and the list was obtained from the HR Department and simple random sampling was done by number categorization. A total of 100 respondents (50 respondents for both the control and the experimental groups) participated in this study. The experiment took place in a room with a similar setup for the production line. Each respondent was requested to perform the simulated task for 2 hr. For the experimental group, the calf massager was turned on every 15 min. At every 15‐min interval after turning on the calf massager, respondents from both groups were required to evaluate their discomfort level on a Borg's scale CR‐10 questionnaire. The results showed that the level of body discomfort among respondents in the experimental group reduced (20–30%) compared with that of the control group. Multivariate analysis results revealed that the discomfort rating for the lower back, knees, thighs, calves, and feet was significantly lower (p < .05) among the experimental group compared with the control group. For lower body parts, the lower back region was statistically significant (p < .05) at the 90th, 105th, and 120th min; the thigh region was statistically significant (p < .05) at the 120th min; the knee region was statistically significant (p < .05) at the 105th and 120th min; the calf region was statistically significant (p < .05) at all minute intervals except the 15th and 45th min, while the feet region, was statistically significant at the 105th and 120th min. Therefore, this study indicates that calf massage treatment is capable of reducing body muscle discomfort during prolonged standing and highlights the significance of calf massage.     

Improved empirical relations for estimating original oil in place recovered during microbial enhanced oil recovery under varied salinity conditions

During microbial enhanced oil recovery (MEOR) processes, the interaction between injection water (IW) and formation water (FW) salinity causes in-situ salinity variation which affects the final oil recovery. The present study explicitly quantifies the Original Oil in Place (OOIP) recovered for different IW and FW salinity conditions through numerical simulation. Based on simulation results, user-friendly empirical correlations were deduced to quickly estimate the OOIP. The results suggest that the OOIP increases drastically in all reservoirs with any initial FW salinity as the adopted salinity of IW is lowered. The study would serve as a tool for making reservoir management decisions.     

Thickness Dependence Study of Electron Beam Evaporated LBMO Manganite Thin Films for Bolometer Applications

La_0.7Ba_0.3MnO₃ (LBMO) thin films with different thicknesses were deposited on Si substrates using an electron beam evaporation technique for bolometer applications. To evaluate the influence of the thickness on their structural, compositional, morphological, and electrical properties, the LBMO thin films were characterized by x-ray diffraction (XRD), energy-dispersive spectroscopy, atomic force microscopy, and a four-probe method. XRD measurements showed that the crystal quality of the LBMO films improved with increasing thickness. The surface morphology revealed that the grain size and surface roughness of the films increased with increasing thickness. The resistivity increased with increasing thickness of the film. The temperature coefficient of resistance of the LBMO films decreased from 5.15%/K to 4.12%/K with increase of the film thickness from 20 nm to 100 nm.     

Effect of substrate bias voltage on the physical properties of dc reactive magnetron sputtered NiO thin films

Nickel oxide (NiO) thin films were prepared on glass substrates at various bias voltages using dc reactive magnetron sputtering technique. The influence of substrate bias voltage on structural, optical and electrical properties was systematically investigated using X-ray diffraction (XRD), SEM, EDS, spectrophotometer and Hall effect studies. The NiO films are crystalline with preferential growth along (2 0 0) plane. The NiO films exhibit optical transmittance of 55% and direct band gap of 3.78 eV at the substrate bias voltage of −75 V. The electrical resistivity decreases as substrate bias voltage increases from 0 to −75 V thereafter it was slightly increased.     

Heavy metal pollution of river water and eco-friendly remediation using potent microalgal species

Pollution of rivers is mainly caused by anthropogenic activities such as discharge of effluent from industrial facilities, maintenance of sewage/effluent treatment plants, and dumping of solid waste on river banks. This study dealt with the pollution issues of the Cooum River in the well-known city of Chennai in South India. Water samples from 27 locations were collected and analyzed for 12 elements, including Ba, B, and Al, as well as heavy metals such as Pb, Cr, Mn, Fe, Co, Ni, Cu, Zn, and Cd. The samples showed levels of these elements that exceeded World Health Organization recommendations. Pearson correlation analysis revealed the inter-dependency among elements, and the contribution of each element based on factor loadings showed its percentage contribution compared to others. Water samples from six significant locations were chosen for remediation with three algae: Chlorella vulgaris, Scenedesmus dimorphus, and Phormedium sp. The uptake of pollutants led to the continuous growth of algae during the incubation period of 15 d, effectively removing heavy metals from the river water. The increasing levels of algal counts and the chlorophyll a content confirmed the algal growth during the incubation period, followed by a declining stage after the incubation period. The scanning electron microscopic images of algae before and after the remediation showed no remarkable modification of morphological patterns. This study showed that the uptake of heavy metals using algae is an effective water pollution remediation measure, making the process practicable in the field on a large scale in the near future.

     

Characterization of CuAlO2 films prepared by dc reactive magnetron sputtering

Thin films of copper aluminum oxide (CuAlO₂) were prepared on glass substrates by dc magnetron sputtering at a substrate temperature of 523 K under various oxygen partial pressures in the range 1 × 10⁻⁴–3 × 10⁻³ mbar. The dependence of cathode potential on the oxygen partial pressure was explained in terms of oxidation of the sputtering target. The influence of oxygen partial pressure on the structural, electrical and optical properties was systematically studied. p-Type CuAlO₂ films with polycrystalline nature, electrical resistivity of 3.1 Ω cm, Hall mobility of 13.1 cm² V⁻¹ s⁻¹ and optical band gap of 3.54 eV were obtained at an oxygen partial pressure of 6 × 10⁻⁴ mbar.     

Optical bonding using silica nanoparticle sol-gel chemistry

A simple method is described to bond optical components using silica nanoparticle sol-gel chemistry. The silica nanoparticles polymerize into highly branched networks that link the surfaces together. The nanoparticle mediated bonding has several advantages to currently used optical joining technologies. The bonding is a room-temperature process and does not require any clean room facilities. The bonded interface has a high mechanical strength and low scattering. The bonding is resistant to organic solvents on silylation with hydrophobic surface groups. This method achieves 100% successful bonding rates between soda-lime glass slides. The bond-setting time can be tailored to allow time for precision optical alignment.     

Effect of substrate temperature on the physical properties of In2O3:Mo films: Prepared by an activated reactive evaporation

Transparent and high conductive molybdenum doped indium oxide (IMO) thin films have been deposited on glass substrates by activated reactive evaporation. The effect of substrate temperature on the structure, surface morphology, electrical, optical and photoluminescence properties of these films were systematically examined and it was found that crystallinity and growth orientation of the films were significantly influenced by substrate temperature. In addition the films exhibited a low electrical resistivity of 5.2 × 10⁻⁴ Ω cm with an optical transmittance 90% in the visible region of the solar spectrum at a substrate temperature of 573 K. Intensive blue PL bands at 415 and 440 nm were observed in the photoluminescence spectrum at room temperature.