Protection efficiencies of surface-active inhibitors in zinc-air batteries

Zinc (Zn) particles in alkaline electrolyte of a Zn-air battery (ZAB) are unstable and prone to corrosion. Zinc oxide (ZnO) generated on the surface of Zn particles affects the electrochemical reactions and reduces the battery efficiency. Thus, inhibiting the self-corrosion rate of Zn particles has become acritical issue for the development of these batteries. In this study, a research endeavor has been attempted by employing three types and concentrations of organic inhibitors in ZABs to constrain Zn anode corrosion. Significant analyses like polarization curve, constant current discharge, AC impedance, and dendrite growth are executed for in-depth understanding of the influences of these inhibitors. The experimental results reveal that the inhibiting efficiency of 10 wt% Sodium dodecyl benzene sulfonate surpassed polyethylene glycol 600 (PEG 600) and polysorbate 20 (Tween 20), with a maximum current density of 476.20 mA/cm² and voltage output of 1.4 V along with discharge capacitance of 10.31 Ah for 2 hours and 8 minutes. Zn anode surface analysis exposes significant dendrite growth and elemental Zn required for passivation suppression. Nevertheless, the results are also justified by Nyquist and Bode plots. Thus, the selected inhibitor will proficiently guarantee the enhanced performance and stability of the ZABs obtained and provide enormous opportunities for its applications.     

Biohythane production from organic waste: Recent advancements,technical bottlenecks and prospects

The availability of fossil fuels is a major factor that determines the economy of a country. However, possible exhaustion of fossil fuel deposits as well as increased pollution, and other adverse effects on the environment has prompted us to search for alternative fuels. This resulted in the development of hythane, a blend of hydrogen with methane, at concentrations of 10%–30%. The breakdown of organic substrates using sequential dark fermentation (DF) and anaerobic digestion (AD) leads to biohythane production. The quality and quantity of biohythane can be improved by altering the following aspects: selection, development, and/or genetic engineering of suitable microbial consortium; the use of cheap, appropriate substrates; improved design of bioreactors; and the implementation of two-stage fermentation system. This review focusses on the mechanism of biohythane production and the different aspects involved in increasing both its production rate and quality. A comparative study has also been done to demonstrate the superiority of biohythane over other biofuels.     

Design and material analysis for prototyping of four arm mechanical microgripper with self-locking and anti-slipping capability

Microsystem Technologies - In this work, a mechanically actuated microgripper is designed with the COMSOL Multiphysics and its analysis is discussed. The mechanical microgripper is having a...     

Reliability Enhancement in Nondestructive Evaluation: Development of Practical Rules for Vacuum Type Helium Leak Tests

In helium leak testing, reliability is an important factor and while attempting to improve this, lot of challenges are being faced. There are contributors for bringing in variations in leak meter readings obtained during system sensitivity check and actual leak test which ultimately affect the final measured leakage rate of test object and they need to be controlled for obtaining reliable results. Response times of leaks are affected by vacuum side volumes, contaminations in vacuum side, leaked gas travel path restrictions on vacuum side and nature of actual leak paths and their gas flow impedances. Hence, actual consideration of real responses of leaks is to be practiced for a reliable test. The traditional concept of using estimate for percentage helium concentration in test hoods is modified by a novel method for its exact determination which improves reliability in tests. Also, practical rules are derived for the reliable identification of leak locations from response time concept. Spurious indications caused by leaks in temporary test rig joints or due to leaks from joints or passages not in the scope of test are other impediments for a reliable test. The response of system changes instantly by spurious indications and hence they require elimination by adopting innovative methods.     

Modelling of Chevron electrothermal actuator and its performance analysis

Microsystem Technologies - In this work, a Chevron electrothermal actuator is designed and its analytical model is developed. Chevron actuator works on the principle of Joules heating effect and...     

Isolation and characterization of drug delivering potential of type-I collagen from eel fish Evenchelys macrura

Acid soluble collagen (ASC) and pepsin-soluble collagen (PSC) from the outer skin waste of marine eel fish (Evenchelys macrura) were isolated and characterized. The prepared collagen was used to test its effective drug delivering potential in vitro condition. Present results were confirmed as collagen by different physico-chemical techniques like SDS-PAGE, HPLC, FTIR and SEM. Further amino acid analysis corroborates isolation of type I collagen. Both ASC and PSC comprising two different α-chains (α 1 and α 2) were characterized as type I and contained imino acid of 190-200 residues, respectively. The denaturation temperatures (T(d)) of ASC and PSC were 38.5 and 35.0?°C, respectively, which is promising as an advantage for biomedical application due to closeness in T(d) to mammalian collagen. Furthermore, the gel and film forming capability of collagen samples containing implant standard antibiotic was proved to be a suitable drug delivering system.     

Overview on mitigation of acrylamide in starchy fried and baked foods

Acrylamide in fried and baked foods has the potential to cause toxic effects in animals and humans. A major challenge lies in developing an effective strategy for acrylamide mitigation in foods without altering its basic properties. Food scientists around the world have developed various methods to mitigate the presence of acrylamide in fried food products. Mitigation techniques using additives such as salts, amino acids, cations and organic acids along with blanching of foods have reduced the concentration of acrylamide. The use of secondary metabolites such as polyphenols also reduces acrylamide concentration in fried food products. Other mitigation techniques such as asparaginase pre‐treatment and low‐temperature air frying with chitosan have been effective in mitigating the concentration of acrylamide. The combined pre‐treatment process along with the use of additives is the latest trend in acrylamide mitigation. © 2018 Society of Chemical Industry     

Effects of nano size mischmetal and its oxide on improving the hydrogen sorption behaviour of MgH2

This paper reports the catalytic effects of mischmetal (Mm) and mischmetal oxide (Mm-oxide) on improving the dehydrogenation and rehydrogenation behaviour of magnesium hydride (MgH₂). It has been found that 5 wt.% is the optimum catalyst (Mm/Mm-oxide) concentration for MgH₂. The Mm and Mm-oxide catalyzed MgH₂ exhibits hydrogen desorption at significantly lower temperature and also fast rehydrogenation kinetics compared to ball-milled MgH₂ under identical conditions of temperature and pressure. The onset desorption temperature for MgH₂ catalyzed with Mm and Mm-oxide are 323 °C and 305 °C, respectively. Whereas the onset desorption temperature for the ball-milled MgH₂ is 381 °C. Thus, there is a lowering of onset desorption temperature by 58 °C for Mm and by 76 °C for Mm-oxide. The dehydrogenation activation energy of Mm-oxide catalyzed MgH₂ is 66 kJ/mol. It is 35 kJ/mol lower than ball-milled MgH₂. Additionally, the Mm-oxide catalyzed dehydrogenated Mg exhibits faster rehydrogenation kinetics. It has been noticed that in the first 10 min, the Mm-oxide catalyzed Mg (dehydrogenated MgH₂) has absorbed up to 4.75 wt.% H₂ at 315 °C under 15 atmosphere hydrogen pressure. The activation energy determined for the rehydrogenation of Mm-oxide catalyzed Mg is ∼62 kJ/mol, whereas that for the ball-milled Mg alone is ∼91 kJ/mol. Thus, there is a decrease in absorption activation energy by ∼29 kJ/mol for the Mm-oxide catalyzed Mg. In addition, Mm-oxide is the native mixture of CeO₂ and La₂O₃ which makes the duo a better catalyst than CeO₂, which is known to be an effective catalyst for MgH₂. This takes place due to the synergistic effect of CeO₂ and La₂O₃. It can thus be said that Mm-oxide is an effective catalyst for improving the hydrogen sorption behaviour of MgH₂.     

Evaluation of embeddable potential sensor for corrosion monitoring in concrete structures

Embeddable potential sensor based on MnO₂ was assembled and characterised in concrete. The stability, reversibility, polarisability and impedance characteristics have been studied with respect to known reference. The corrosion performance of reinforced steel with respect to MnO₂ sensor was monitored by different electrochemical techniques. Reversibility of MnO₂ sensor indicated that difference of ±5 mV between the forward and reverse scan indicates the better reversibility characteristics in concrete. The rebar potentials (E_R) of steel with respect to MnO₂ are −315 and −525 mV for passive and active conditions of rebar in concrete. The corrosion current from potentiodynamic polarisation and R_ct from a.c. impedance technique clearly differentiated the behaviour of steel embedded in chloride contaminated concrete (active condition) from uncontaminated concrete (passive condition) with respect to MnO₂ sensor. All these studies revealed that corrosion monitoring of steel in concrete using embedded MnO₂ as a better potential sensor for steel in concrete. In addition it is easy to fabricate for amenable miniaturisation, varied configuration as demanded for corrosion monitoring in concrete structures.     

Unsupervised Quick Reduct Algorithm Using Rough Set Theory

Feature selection (FS) is a process to select features which are more informative.It is one of the important steps in knowledge discovery.The problem is that not all features are important.Some of the features may be redundant,and others may be irrelevant and noisy.The conventional supervised FS methods evaluate various feature subsets using an evaluation function or metric to select only those features which are related to the decision classes of the data under consideration.However,for many data mining applications,decision class labels are often unknown or incomplete,thus indicating the significance of unsupervised feature selection.However,in unsupervised learning,decision class labels are not provided.In this paper,we propose a new unsupervised quick reduct (QR) algorithm using rough set theory.The quality of the reduced data is measured by the classification performance and it is evaluated using WEKA classifier tool.The method is compared with existing supervised methods and the result demonstrates the efficiency of the proposed algorithm.