Phase change materials,their synthesis and application in textiles—a review

Phase change materials (PCMs) are widely being used in thermal energy storage systems for solar engineering, building materials, heat pumps, spacecraft, and in textile field especially smart and technical textiles. There are large numbers of organic and inorganic PCMs that possess a wide range of melting and solidifying temperature which attracts researcher’s attention for their applications in different fields. This review paper summarizes the investigation and analysis of the available organic and inorganic PCMs, different encapsulating techniques, characterization techniques, incorporation into fiber and pad application on textiles with practical applications in the field of smart textiles.     

Effect of Boronizing on Operating Stability of Steel AISI 304L under Erosion Impact of Hard Particles

Metal Science and Heat Treatment - The effect of solid boronizing at 950°C for 2 and 4 h on the phase composition, microstructure, hardness and abrasive wear of steel AISI 304L is studied...     

Performance comparison of differential evolution techniques on optimization of feeding profile for an industrial scale baker’s yeast fermentation process

Differential evolution (DE) is one of the novel evolutionary optimization methods used for solving the problems that consist of nondifferentiable, nonlinear and multi-objective functions. In this presented work, the classical DE technique and its various versions, such as opposition based on differential evolution (ODE), adaptive differential evolution (ADE), adaptive opposition based on differential evolution (AODE) which is an advanced version of ODE, are presented to determine the optimal feeding flow profile of an industrial scale fed-batch baker’s yeast fermentation process. The main objective in any fed-batch fermentation process optimization is both to maximize the amount of the biomass at the end of the process and to minimize the ethanol formation during the process. Four different cases regarding the initial condition of the fermentation process were considered so as to evaluate the performances of proposed algorithms. Besides, two strategies of mutation and crossover operators, which are the most popular in DE’s applications, were utilized for performance comparison tests. The influence of initial seed value, initial condition of the process, and both of the mutation and crossover strategies have been investigated for all the different classic, opposition-based, self-adaptive and adaptive opposition-based mechanisms. To demonstrate the performance comparison of the of DE’s techniques, the experimental data collected from the fermentor with volume of 100 m³ are presented with the optimization results obtained by using all the interested DE techniques for the same initial conditions.     

Characterization of a Cohesive Soil Bed using a Cone Pressuremeter

A new cone pressuremeter has been developed at the University of Engineering and Technology, Lahore-Pakistan. The new device is called the Akbar Pressuremeter (APMT). This paper is based on the APMT testing of a cohesive soil deposit comprised of low plastic lean clay (CL) to sandy silty clay (CL-ML). The APMT testing, using a full-displacement technique, standard penetration tests and undisturbed samples, was carried out at two locations. The soil strength and type were determined using the undisturbed samples. The applied pressure-cavity strain curves of the APMT tests performed at different levels were analysed to determine soil strength and stiffness. The undrained shear strength of the undisturbed samples was determined in the laboratory by unconfined compression tests. This paper provides a comparison of the parameters interpreted from the pressuremeter and those determined from other field and laboratory methods.     

Facile Synthesis of Ferrocene-Based Polyamides and Their Organic Analogues Terpolyamides: Influence of Aliphatic and Aromatic Sequences on Physico-Chemical Characteristics

Efforts have been devoted to synthesize and characterize processable polymers with desired properties. Herein, four different series of aromatic and aliphatic terpolyamides were prepared via solution phase polycondensation of 4,4′-oxydianiline and hexamethylenediamine (HMDA) with various diacids chlorides (isophthalyol dichloride, terepthalyol dichloride, 1, 1′-ferrocene dicarboxylic acid chloride and trans-azobenzene-4, 4′-dicarbonyl chloride). The structural, morphological and physico-chemical nature of as prepared polymers was explored by Fourier-transform infrared spectroscopy, scanning electron microscopy, thermal analysis (TGA and DSC), and wide-angle x-ray diffraction. Moreover, an aliphatic diamine was incorporated in varying concentration as a flexible methylene spacer and the effect of its concentration on the properties of polyamides was also studied. Changes in various physico-chemical properties such as solubility, inherent viscosity, surface morphology and flame retarding behaviour were investigated. Marked difference in morphology and solubility was observed with the change in the ratio of segments in the chain. Inherent viscosities of polymers ranged from 1.8052–1.6274 dl/g indicating reasonably moderate molecular weights. Interestingly, ferrocene based aromatic polymers were more thermally stable (T_g 260 °C, T_i 310 °C, T_h 525 °C, T_f 720 °C, for PF₀), and also found to exhibit best flame retarding behavior (limiting oxygen index value for PF₀is LOI 33.15%).

     

Fluorescence and photon transmission techniques for studying film formation from PS/GO nanocomposites

Polymer Bulletin - Steady-state fluorescence and UV–Vis techniques were used to study the film formation behavior of composites consisting of pyrene (P)-labeled polystyrene (PS) latex and...