Enhanced Visible Light Photocatalytic Activity of Curcumin‐Sensitized Perovskite Bi0.5Na0.5TiO3 for Rhodamine 6G Degradation

Curcumin‐sensitized perovskite Bi_0.5Na_0.5TiO₃ (BNT) was synthesized for visible light photocatalytic decolorization of rhodamine 6G (Rh6G). Cube‐shaped perovskite BNT was synthesized by solid‐state route, and curcumin sensitization was performed using hydrothermal method. The surface sensitization of curcumin was analyzed by UV–Vis absorption spectra and FTIR. The degradation kinetics of Rh6G over Cur‐BNT were investigated and discussed through first‐order Langmuir–Hinshelwood kinetic model. The effect of catalyst dose on photocatalytic decolorization process was investigated. Photocatalysis was performed with different scavengers to investigate the role of active hole and radical species and photocatalytic degradation mechanism of Rh6G.     

Recent advances for serial processes of hazardous chemicals in fully integrated microfluidic systems

The development and enlargement of toxic and hazardous chemicals are severely limited by health and safety concerns. We summarize studies on fully integrated micro-chemical systems and total processes to reduce accidental exposure to various regents that are toxic, explosive, or carcinogenic, which significantly improved the safety of work involving risky compounds. This review covers the leak-free continuous-flow processes of hazardous chemicals in fully integrated microfluidic systems, specially denoted as micro-total envelope systems (μ-TESs), that are conducting a serial process of the generation of hazardous reagents, in-situ purification and separation, subsequent reaction, and product isolation with improved efficiencies. These attempts suggest safe and efficient tools and processes of useful but hazardous chemicals for researchers and manufacturing workers in the field of pharmaceutic discovery, natural products, biology as well as materials synthesis.     

Fabrication of poly (vinyl alcohol)/ovalbumin/cellulose nanocrystals/nanohydroxyapatite based biocomposite scaffolds

Biocomposite scaffolds composed of PVA, ovalbumin, cellulose nanocrystals, and nanohydroxyapatite were fabricated by freeze-drying method. The results revealed that the different fractions of nanohydroxyapatite and cellulose nanocrystals provide the mechanical strength and stiffness to the desired biocomposite scaffolds. In vitro biomineralization showed the formation of apatite onto the surface of obtained biocomposite scaffolds and increased as amount of nanohydroxyapatite increased. The obtained results suggest that the different combinations of these four biomaterials can be used to fabricate highly porous scaffolds with desired mechanical performance and degradation rate by adjusting ratio for potential use in low load-bearing applications.     

Hierarchical growth of BiOCl on SrO‐Bi2O3‐B2O3 glass‐ceramics for self‐cleaning applications

We have grown hierarchical structure of bismuth oxycloride (BiOCl) on SrO‐Bi₂O₃‐B₂O₃ (SBBO) transparent glass‐ceramic. SBBO glass‐ceramics were fabricated via conventional melt‐quenching technique while BiOCl was grown by etching the glass via HCl. Enhanced visible light driven photocatalytic activity and increasing hydrophobic feature were observed on BiOCl grown SBBO than as‐quenched SBBO glass‐ceramics. Contact angle analysis showed maximum contact angle of 130.7° on the surface of most BiOCl grown SBBO glass‐ceramic. Furthermore, under visible light illumination water contact angle decreased from 130.7° to 30.8°. Such photo‐induced hydrophilicity and catalytic performance in translucent glass‐ceramics lead self‐cleaning applications.     

Studies on Micellar Behavior of PEO‐PBO or PEO‐PBO‐PEO Copolymers,or Surface Active Amphiphilic Ionic Liquids in Aqueous Media and Exploration of the Micellar Solutions for Solubilization of Dexamethasone and its Delayed Release

The aggregation behavior of a di‐ and tri‐block copolymers of type PEO‐PBO, PEO‐PBO‐PEO, surface‐active ionic liquid (SAIL) of type 4‐dodecyl‐4‐methylmorpholinium chloride [C₁₂mmor][Cl], and 1‐dodecyl‐1‐methylpyrrolidinium chloride [C₁₂mpyrr][Cl]) in water as well as in 10 mM of a poorly water soluble dexamethasone (dex) aqueous solution was studied by determining the critical micelle concentrations using drug solubilization, surface tension, and isothermal titration calorimetry (ITC) methods. ITC measurements were also made on solutions prepared by mixing the micellar aqueous solutions of copolymers and simple aqueous solutions of SAIL across the mole fractions at three different temperatures (298.15, 308.15, and 318.15 K). The thermodynamic parameters, namely Gibbs free energy (ΔG_m), enthalpy (ΔH_m), and entropy (ΔS_m), of micellization were calculated, and it was observed that the negative ΔG_m and positive ΔS_m for the mixture solutions increase with the increase in mole fraction of SAIL. Otherwise, the micellization is reported to be a spontaneous and highly entropy‐driven process. The dex‐solubilized micellar solutions were mixed with agar to obtain standing gels. The gel samples were dry‐cast into thin films, and the release of dex from films by simple dilution was monitored by UV measurements. The drug release data was fitted to several mechanistic models, and it was inferred that the release mechanism for dex from thin films is non‐Fickian for mixtures and Fickian in copolymer or SAIL micellar aqueous solutions. The transport of dex is diffusion‐controlled with diffusivities of 5.8–12 × 10^?11 m² s^?1 for copolymer micelles, 5–11 × 10^?11 m² s^?1 for micelles of SAIL, and 3–14 × 10^?11 m² s^?1 for the mixed micelles of copolymer and SAIL in aqueous media.     

An improved method for the determination of saturationcharacteristics of switched reluctance motors

Experimental determination of magnetization characteristics of switched reluctance motors (SRMs) is quite important in their accurate performance prediction. Over the last decade, various experimental procedures have been used to obtain these characteristics. Every evolved new method has its own limitations and constraints. This paper describes an improved, simple and cost effective experimental procedure and an equally simple post-experimental data processing to obtain the flux-linkage-current curves at varying rotor positions of the SRM. The experimental results on a 4 kW, four-phase, 8/6 pole SRMs show the effectiveness of the method and the results compare well with the previously results compare well with the previously published results of similar and higher rating SRM's     

Hypsometric Integral Estimation Methods and its Relevance on Erosion Status of North-Western Lesser Himalayan Watersheds

Assessment of erosion status of a watershed is an essential prerequisite of integrated watershed management. This not only assists in chalking out suitable soil and water conservation measures to arrest erosion and conserve water but also helps in devising best management practices to enhance biomass production in watersheds. The geologic stages of development and erosion proneness of the watersheds are quantified by hypsometric integral. The estimation of hypsometric integral is carried out from the graphical plot of the measured contour elevation and encompassed area and by using empirical formulae. In this study, efforts were made to estimate the hypsometric integral values of the Sainj and Tirthan watersheds and their sub watersheds in the Lesser Himalayas using four different techniques, and to compare the procedural techniques of its estimation and relevance on erosion status. It was revealed that the hypsometric integral calculated by elevation–relief ratio method was accurate, less cumbersome and easy to calculate within GIS environment. Also comparison of these hypsometric integral values revealed that the Sainj watershed (0.51) was more prone to erosion than the Tirthan watershed (0.41). Further, the validation of these results with the recorded sediment yield data of 24 years (1981–2004) corroborated that the average annual sediment yield during this period for Sainj watershed (0.53 Mt) was more than that of the Tirthan watershed (0.3 Mt). Thus, the hypsometric integral value can be used as an estimator of erosion status of watersheds leading to watershed prioritization for taking up soil and water conservation measures in watershed systems.