Scrutinizing the influence of peroxide crosslinking of dynamically vulcanized EVA/TPU blends with special reference to cable sheathing applications

A novel thermoplastic vulcanizate (TPV) based on the blends of ethylene vinyl acetate/thermoplastic polyurethane (EVA/TPU) at various blend ratios has been developed via dynamic vulcanization at 180 °C using di‐(2‐tert‐butyl peroxy isopropyl) benzene (DTBPIB) peroxide as the cross‐linking agent. Modification of the EVA/TPU blends via dynamic crosslinking significantly improves the tensile strength and modulus of the system and the improvement is more significant for EVA/TPU 50/50 and 60/40 blends. AFM study shows that crosslinked EVA particles are dispersed in the continuous TPU matrix and the dispersed EVA domain sizes are relatively smaller in EVA/TPU 50/50 and 60/40 blends leading to good mechanical properties. FTIR spectroscopy has been used to characterize the specific chemical changes occurring due to dynamic vulcanization. This TPV has excellent retention of physico‐mechanical properties even after reprocessing twice and the blends also have very good thermal resistance as indicated by aging study. The samples were found to exhibit remarkable improvement in oil resistance property as compared to their uncrosslinked counterpart. The creep behavior of the blends significantly improves after dynamic crosslinking and blends with higher TPU content show better creep resistance. Volume resistivity of all the peroxide vulcanized blends is in the range of 10¹³ ohm cm, which is suitable for cable sheathing application. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43706.     

Design and development of modular fuel cell stacks for various applications

Polymer electrolyte membrane fuel cell (PEMFC) stacks are conventionally made by assembling a large numbers of cells together connected electrically in series. The number of cells and the area of the electrodes determine the capacity of such a stack. One of the reasons for non-proliferation of the fuel cell systems in many applications is due to the high cost involved in making these units. Cost reduction of the fuel cell components, fuel cell stacks and fuel cell system are being extensively pursued. One of the options for cost reduction is thro’ fabricating the fuel cells in smaller scale industrial units as their overheads are low. To attract small scale entrepreneurs (SSE) the capital investment has to be minimum. If compact fuel cell stacks of size ranging from 200 to 300 W can be produced comfortably, the SSE's can be encouraged to set up manufacturing units and they can become original equipment manufacturer (OEM) supplier to system integrators who could develop fuel cell systems of various capacities by simply connecting these compact stacks electrically in series or parallel depending on the end use. Such modular architecture would reduce the cost and improve the reliability of manufacture and increase the range of applications. This modular construction not only allows the materials and manufacturing technologies for components and stacks for uniformity but also suitable for homogenous large volume production. The geometry of the stacks allows easy installation even in crowded or compact areas. Centre for Fuel Cell Technology (CFCT) has demonstrated PEMFC stacks of 1–3 kW capacities. These stacks are single units with fixed voltage and current capabilities. CFCT is now embarked on a program to explore the possibility of introducing modular architecture for various applications of fuel cell systems. In this context, CFCT has recently developed a 250 W module which can be cooled either by air or water. The present paper discusses the concept and design of a modular architecture.     

Hydrogen production and end-product synthesis patterns by Clostridium termitidis strain CT1112 in batch fermentation cultures with cellobiose or α-cellulose

Hydrogen (H₂) production and end-product synthesis were characterized in a novel, mesophilic, cellulolytic, anaerobic bacterium, Clostridium termitidis strain CT1112, isolated from the gut of the termite, Nasutitermes lujae. Growth curves, pH patterns, protein content, organic acid synthesis, and H₂ production were determined. When grown on 2 g l⁻¹ cellobiose and 2 g l⁻¹ α-cellulose, C. termitidis displayed a cell generation time of 6.5 h and 18.9 h, respectively. The major end-products synthesized on cellobiose included acetate, hydrogen, CO₂, lactate, formate and ethanol, where as on cellulose, the major end-products included hydrogen, acetate, CO₂ and ethanol. The concentrations of acetate were greater than ethanol, formate and lactate on both cellobiose and α-cellulose throughout the entire growth phase. Maximum yields of acetate, ethanol, hydrogen and formate on cellobiose were 5.9, 3.7, 4.6 and 4.2 mmol l⁻¹ culture, respectively, where as on cellulose, the yields were 7.2, 3.1, 7.7 and 2.9 mmol l⁻¹ culture, respectively. Hydrogen and ethanol production rates were slightly higher in C. termitidis cultured on cellobiose when compared to α-cellulose. Although, the generation time on α-cellulose was longer than on cellobiose, H₂ production was favored corresponding to acetate synthesis, thereby restricting the carbon flowing to ethanol. During log phase, H₂, CO₂ and ethanol were produced at specific rates of 4.28, 5.32, and 2.99 mmol h⁻¹ g dry weight⁻¹ of cells on cellobiose and 2.79, 2.59, and 1.1 mmol h⁻¹ g dry weight⁻¹ of cells on α-cellulose, respectively.     

Functionalization of carbons for Pt electrocatalyst in PEMFC

One of the limitations of conventional carbon-supported Pt electrocatalyst in Proton Exchange Membrane Fuel cell (PEMFC) is the carbon corrosion during start-up and shut-down of a fuel cell. The present work investigates the stability of three different carbon blacks and their functionalized forms as supports for Pt electrocatalysts. Acetylene black (AB) as a low surface area carbon shows a higher degree of graphitization and effective functionalization than Vulcan carbon and Ketjan black. Electrochemical tests on corrosion studies show that the AB and its functionalized form (f-AB) as support for Pt electrocatalyst exhibits good electrochemical activity with an ECSA of 52 m²g^-1 and 78 m²g^-1 and excellent corrosion resistance with minimum ECSA loss of 6% and 16% for Pt/AB and Pt/f-AB, respectively, satisfying the DoE target (<40% ECSA loss.) This makes the Pt/f-AB a promising durable electrocatalyst for PEMFC with improved activity and durability.     

Effect of magnetic field on two-layered natural/thermocapillary convection

Heat transfer in a two-layered fluid system is of great importance in a variety of applications. Control and optimization of convective heat transfer of the immiscible fluids needs complete understanding of all phenomena, especially those induced by surface tension at the fluid interface. The present work is focused on rather complex convective flow and heat transfer phenomena in a cavity, which can be subject to both buoyancy and thermocapillary effects in addition to the influence of magnetic field applied for flow control. With the encapsulant liquid posing magnetic properties, a magnetic force can arise to either enhance or counterbalance the gravity effect when the cavity is placed in a non-uniform magnetic field. In our study, the velocity and temperature distribution of the system can be significantly altered to change the heat transfer by varying intensity and gradient of the applied magnetic field. Preliminary results of numerical computation presented here are for a two-layered liquid cavity MnCl₂·4H₂O and Fluorinert FC40 under various magnetic fields intensities.     

Co-hydrothermal gasification of microbial sludge and algae Kappaphycus alvarezii for bio-hydrogen production: Study on aqueous phase reforming

In this study, wastewater obtained from a sewage treatment plant was treated successively by using microbial consortium and macroalgae Kappaphycus alvarezii to generate microbial sludge and algal biomass. The production of green fuel was carried out via co-gasification of microbial sludge and macroalgae Kappaphycus alvarezii for a duration of 60 min, feedstock to solvent ratio (5 to 20 g of feedstock in 200 mL), sludge to algae ratio (ranging from 1:1 to 3:1) and temperature (300–400 °C) respectively. Maximum bio-hydrogen yield was 36.1% and methane yield was 38.4% at a temperature of 360 °C at a feedstock to solvent ratio of 15:200 g/mL and sludge to algae ratio of 2:1 individually. The liquid by product of co-gasification process was later subjected to photocatalytic reforming, resulted in an enhanced hydrogen composition of 61.25%.     

Improving the performance of sulfonated polymer membrane by using sulfonic acid functionalized hetero-metallic metal-organic framework for DMFC applications

Proton transport played a crucial part in the fuel cells, sensors, and batteries. The electrolyte used in fuel cells should possess high proton conductivity and good chemical stability. Herein, taking advantage of the high proton conductivity of metal-organic framework (MOF) and the good chemical stability of branched polymers, a new heterometallic mediated MOF (Zr-Cr-SO₃H) is synthesized and utilized as a filler in the highly branched sulfonated polymer (BSP). In addition, Zr-SO₃H MOF is also prepared for comparison. Transmission electron microscope study shows that the prepared MOF particles are spherical in size and interconnected through nanosheets. The optimized quantity of MOFs inside the polymer matrix improves the water sorption, mechanical property, and proton conductivity. The composite membranes display an improved open-circuit voltage than the pristine BSP membrane. By comparing the Zr-SO₃H MOF incorporated composite membrane, Zr-Cr-SO₃H MOF incorporated composite membranes display higher proton conductivity and peak power density in a single-cell test. In particular, the single-cell fabricated with Zr-Cr-SO₃H MOF incorporated composite membrane is able to reach the peak power density of 64.6 mWcm⁻² at 60°C, which is 26% greater than the Nafion 212 membrane. Furthermore, this work offers a new strategy for the utilization of hetero-metal MOF as a filler for proton exchange membrane applications.     

Safety evaluations on ethanolic extract of red cabbage (Brassica oleracea L.) in mice

The present study has carried out safety evaluations on an ethanolic extract of red cabbage (RC) leaves in terms of acute and subchronic oral toxicity tests as per Organisation for Economic Cooperation and Development (OECD) guidelines in Swiss albino mice. Single-dose administration of RC extract (1000, 2000, 3000, 4000, or 5000 mg/kg body weight) to Swiss albino mice did not manifest toxicity or any significant adverse behavioral alterations. Chronic administration of RC extract (1000, 2000, and 3000 mg/kg body weight) for 28 d also did not register any significant alterations in fluid intake, organ weights, plasma lipid profile, plasma creatine kinase-MB, lactate dehydrogenase, aspartate transaminase, alanine transaminase, creatinine, electrolytes, and calcium levels, and the total blood count showed a nonsignificant change. However, significant reduction in body-weight gain, food intake, red blood cell count, and hemoglobin content along with higher alkaline phosphatase, bilirubin, and urea levels was observed in mice treated with 3000 mg/kg body weight for 28 d. Since there was no mortality up to a dose of 5000 mg/kg body weight, 50% lethal dose (LD(50)) could not be determined, and hence, it can be assumed that, LD(50) of RC extract is >5000 mg/kg. No observable adverse effect level dose of the RC extract was found to be 2000 mg/kg body weight. Hence, consumption of RC extract for various medicinal purposes is safe. Practical Application: RC is a popularly consumed foodstuff that has been ubiquitously reported to exert medicinal properties. It is mandatory to understand the highest permissible consumption limit of any food supplement to avoid toxicity. This study establishes the safe dose of RC. These results can be of relevance for the scientific fraternity as well as laymen who consume this vegetable or its phytochemical preparation.     

Hybrid Approach for Privacy Enhancement in Data Mining Using Arbitrariness and Perturbation

Imagine numerous clients, each with personal data; individual inputs are severely corrupt, and a server only concerns the collective, statistically essential facets of this data. In several data mining methods, privacy has become highly critical. As a result, various privacy-preserving data analysis technologies have emerged. Hence, we use the randomization process to reconstruct composite data attributes accurately. Also, we use privacy measures to estimate how much deception is required to guarantee privacy. There are several viable privacy protections; however, determining which one is the best is still a work in progress. This paper discusses the difficulty of measuring privacy while also offering numerous random sampling procedures and statistical and categorized data results. Furthermore, this paper investigates the use of arbitrary nature with perturbations in privacy preservation. According to the research, arbitrary objects (most notably random matrices) have "predicted" frequency patterns. It shows how to recover crucial information from a sample damaged by a random number using an arbitrary lattice spectral selection strategy. This filtration system's conceptual framework posits, and extensive practical findings indicate that sparse data distortions preserve relatively modest privacy protection in various situations. As a result, the research framework is efficient and effective in maintaining data privacy and security.     

The Effect of Acoustic Field on the Thermal Conductivity of composite propellants

A study is conducted to determine the effect of acoustic field on the thermal conductivity of composite propellants based on poly- butadiene and polyurethane binders. The thermal conductivity of the propellant is determined by a specially designed equipment. The thermal conductivity measurements are made in steady state conditions and in an acoustic field of constant amplitude at various frequencies ranging from 1 kHz to 6 kHz and at different temperatures ranging from 30°C to 50°C. The results indicate that the thermal conductivities of the composite propellants increase when they are subjected to an acoustic field. The data obtained are presented in the paper. Since the burning behaviour of solid propellants is influenced also by its thermal conductivity, the present work may be of direct relevance in improving upon some of the existing burning rate and combustion models.