Microwave Assisted Modulation of Vat Dyeing of Cellulosic Fiber: Improvement in Color Characteristics

The role of radiations in textile processing is gaining attention due to its low cost, energy effectiveness and eco-friendly process. This study is concerned with the improvement in modulation of microwave assisted vat dyeing of cellulosic fiber. It was found that radiation treatment of both cotton fabric and dye solution for 1 min gives good color strength, while for redox reaction, 2.5 g of NaHSO₃, 2 mL of CH₃COOH, and 1.5 mL of H₂O₂ are the optimized conditions which show it is a cost-effective tool. Good color strength was obtained at 65 °C for 1 h dyeing using 50 mL of optimal solution in dye bath at pH 9. Finally, ISO standards for color fastness to light, washing, rubbing and perspiration were applied at 0.5–2.5% of shade at optimal conditions which showed that microwave treatment has enhanced the color characteristics. Hence, the technique can successfully and easily be employed for surface modification of fabric for good quality dyeing with various classes of dyes.     

Formulation strategy towards minimizing viscosity mediated negative food effect on disintegration and dissolution of immediate release tablets

Food induced viscosity can delay disintegration and subsequent release of API from solid dosage form which may lead to severe reduction in the bioavailability of BCS type III compounds. Formulations of such tablets need to be optimized in view of this postprandial viscosity factor. In this study, three super disintegrants, croscarmellose sodium (CCS), cross-linked polyvinylpolypyrrolidone (CPD), and sodium starch glycolate (SSG) were assessed for their efficiency under simulated fed state. Tablets containing these disintegrants were compressed at 10 and 30?KN, while taking lactose as a soluble filler. In addition to other compendial tests, disintegration force of these formulations was measured by texture analysis. Comparison of parameters derived from force – time curves revealed a direct relation of maximum disintegration force (F_max) and disintegration force development rate (DFDR) with compressional force in fasted state, whereas an inverse relationship of F_max and DFDR with compressional force was observed in fed state. The gelling tendency of disintegrants influenced the rate of release of API in simulated fed and fasted states when compressional force was changed. These observations recommend the evaluation of formulations in simulated fed state, in the development stage, with an objective of minimizing the negative impact of food induced viscosity on disintegration. Use of disintegrants that act without gelling or can counteract the effect of gelling is recommended for tablet formulations with reduced disintegration time (DT) and mean dissolution time (MDT) in fed state, respectively.     

Estimating the Aquifer’s Renewable Water to Mitigate the Challenges of Upcoming Megadrought Events

Water Resources Management - In arid and semi-arid regions of the world, the occurrence of prolonged drought events (megadroughts) associated with climate change can seriously affect the balance...     

Hydrogen production by silica membrane reactor during dehydrogenation of methylcyclohexane: CFD analysis

A comprehensive computational fluid dynamic model has been developed using COMSOL Multiphysics 5.4 software to predict the behavior of a membrane reactor in dehydrogenation of methylcyclohexane for hydrogen production. A reliable reaction kinetic of dehydrogenation reaction and a permeation mechanism of hydrogen through silica membrane have been used in computational fluid dynamic modeling. For performance comparison, an equivalent traditional fixed bed reactor without hydrogen removal has been also modeled. After model validation, it has been used to evaluate the operating parameters effect on the performance of both the silica membrane reactor and the equivalent traditional reactor as well. The operating temperature ranged between 473 and 553 K, pressure between 1 and 2.5 bar, sweep factor from ?6.22 to 25 and feed flow rate from 1 to 5 × 10^?6 mol/s. The membrane reactor performed better than the equivalent traditional reactor, achieving as best result complete methylcyclohexane conversion and 96% hydrogen recovery.     

Effect of Shot Peening Operation on the Microstructure and Wear Behavior of AZ31 Magnesium Alloy

Protection of Metals and Physical Chemistry of Surfaces - Shot peening is a treatment used to increase surface hardness and wear resistance. In this study, the effect of shot peening on the...     

An Investigation of Low Velocity Impact Properties of Rotationally Molded Skin–Foam–Skin Sandwich Structure

In this study, the low velocity impact properties of rotationally molded skin–foam–skin sandwich structures were investigated experimentally since there is a need for a greater understanding of the impact behavior of these composites in service to extend the range of their applications. Polyethylene rotationally molded sandwich structures were manufactured at various skin and core layer thickness combinations and tested using an instrumented low velocity drop weight impact testing machine at 20–100 J impact energy levels, at room temperature. This allowed the identification of the impact response, failure mode, and the effects of the skin and core layer thickness on impact resistance. Force–deflection curves, maximum force, contact time, maximum deflection versus impact energy curves were analyzed. Samples were seen to fail due to the indentation dart piercing the upper and lower skins, with crushing and consolidation seen in the core foamed layer. Delamination at the core/skin interface was not observed. It was found that fracture initiates from the lower skin and then continues to grow to the upper skin via the foamed core layer. The impact resistance was noted to increase with increasing skin and core layer thickness; though an increase in skin layer thickness had a greater contribution than an increase in the core layer thickness. POLYM. ENG. SCI., 60: 387–397, 2019. © 2019 Society of Plastics Engineers     

Ethanol shock enhances the recovery of anthocyanin from lowbush blueberry

Deactivation of polyphenol oxidase (PPO) in natural products is essential for downstream processing of functional molecules used as food or food additives, particularly those served as antioxidants. In the present work, we identified two proteins with PPO activity from lowbush blueberry using ammonium sulphate precipitation and chromatography procedures. Deactivation of these proteins was studied using aqueous solutions of ethanol of different concentrations. The PPO activity was recovered after ethanol removal for the protein samples previously soaked in a low concentration ethanol solution. A complete and unrecoverable deactivation of the proteins was achieved using ethanol with concentration over 70% (v/v), as manifested by the significant changes in circular dichroism (CD) and fluorescence spectroscopy measurements. Based on these findings, we propose a new extraction process for blueberry anthocyanin, in which an ethanol shock, i.e. soaking blueberry fruit in a 70% (v/v) ethanol solution for 1 h, is implemented before subsequent procedures. This new process increases the anthocyanin yield by 55% in comparison to that without the ethanol shock.     

Aircore mechanism during draining based on influence of pressure difference and drain port diameter

An understanding of the mechanism of aircore phenomenon during draining is very important. In this study, numerical simulations were conducted for different pressurized and suction pressure water tanks, as well as for different drain port diameters, to explain and validate the proposed aircore mechanism. It was found that increasing the pressure at the top surface of the tank results in suppression of the aircore, whereas an increase in the suction pressure at the drain port outlet enhances the development of the aircore. For different drain port diameters, it was observed that the duration of the aircore during draining decreases with a decrease in the drain port diameter, and that the aircore is suppressed for a very small drain port diameter.