Surface smoothening and characterization of silk fibers of Antheraea assamensis Helfer (muga) using some natural agents

Cocoons of Antheraea assamensis (muga) silkworm were treated with different classes of natural-acidic (Citrus limon and Dillenia indica) and alkaline (Musa balbisiana) materials with the aim to elucidate their effectiveness as degumming agents. The tensile strength of silk fibers increased significantly after bio-degumming compared to industrial degumming using sodium carbonate. Scanning electron microscopy of bio-degummed fibers appeared clean and even with clear individual fibroin filaments. FTIR studies confirmed that bio-degumming resulted in holding the innate nature of muga silk. Under the implemented experimental conditions, M. balbisiana and C. limon functioned as most efficient degumming agents, followed by D. indica. The findings of this study propose the use of such eco-friendly degumming practices over the usual harsh industrial treatments for obtaining applaudable quality of silk with robust strength necessary for both textile and biomaterial purpose, besides reducing the impact of chemical toxicity on the environment.     

Isolation and characterization of biosurfactant producing microorganisms from petroleum contaminated soil samples for EOR and bioremediation

Using of biosurfactant producing microorganisms for pipeline cleaning, bioremediation, enhanced oil recovery, etc. is a much soughed approach of petroleum industry. Although, many alternatives are available to serve these purposes, being ecofriendly and economic, microbial application is considered superior than most of the alternatives. This paper presents a comprehensive study on effectiveness of bacterial strain isolated from oil contaminated soil sample of Lakwa oilfield for required purposes. Its temperature sustainability and surfactant production capability was studied. Further characteristics of the produced biosurfactant were assessed through Emulsification Index measurement, Fourier Transform Infrared Spectra, Drop Collapse Test, Contact Angle and Viscosity measurement.     

Obtaining vehicle parameters from bridge dynamic response: a combined semi-analytical and particle filtering approach

Railway Engineering Science - Dynamic load imposed on the bridge by moving vehicle depends on several bridge–vehicle parameters with various uncertainties. In the present paper, particle...     

A study on the synthesis,characterization and catalytic activity of ruthenium-substituted MFI (Mobil Five) zeolite

Hydrothermal synthesis was adapted to prepare a series of ruthenium (Ru)-incorporated Mobil Five (MFI) zeolite materials with silicon (Si) to aluminium (Al) ratio of 100 and with Al to Ru ratios 1:1, 2:1 and 3:1. An X-ray diffractometer (XRD) and FT-IR were employed to identify the formation of the zeolite phase. A favourable environment was maintained in the gel to overcome the difficulties of isomorphous substitution of ruthenium into the MFI framework. The unit cell volume change and the shift in XRD reflection positions showed a positive correlation with increased ruthenium content in the samples. UV–Vis (DRS) spectra confirmed the position of ruthenium in the T-site in the MFI structure. Thermogravimetric analysis was carried out for studying water and template removal patterns and also for studying the thermal stability of the synthesized samples. Formation of uniform rectangle- and twinned-rectangle-shaped MFI particles with particle size approaching \(27\,\upmu \hbox {m}\) was confirmed by scanning electron microscopy. Energy-dispersive X-ray analysis was carried out for quantification of Si, Al and Ru. The catalytic activities of the synthesized samples for the hydroxylation of phenol was investigated, the major products being catechol and hydroquinone.     

Parameter optimization of 5.5 GHz low noise amplifier using multi-objective Firefly Algorithm

Microsystem Technologies - This work presents an optimal design of low noise amplifier (LNA) using Firefly Algorithm (FA). In this work we have implemented FA in optimizing various parameters of...     

ANALYSIS OF THE PERFORMANCE OF NON-UNIFORMLY ACTIVE CATALYST PELLETS FOR A NON-ISOTHERMAL SERIES REACTION

An analysis of the influence of the non-uniform distribution of the active species in a catalyst pellet on the effectiveness factor and selectivity for the case of a series non-isothermal reaction is carried out. The case in which the desired reaction has a lower activation energy than the undesired reaction is considered. The effect of different reaction parameters on the selectivity for a single pellet is studied, and the optimum activity distribution is determined for high values of Thiele modulus. It is shown that temperature gradients within the pellet have a detrimental effect on local and overall selectivity and that these gradients are a strong function of the distribution of catalytically active material within the pellet.     

Low noise constant current source for bias dependent noise measurements

A low noise constant current source used for measuring the 1∕f noise in disordered systems in ohmic as well as nonohmic regime is described. The source can supply low noise constant current starting from as low as 1 μA to a few tens of milliampere with a high voltage compliance limit of around 20 V. The constant current source has several stages, which can work in a standalone manner or together to supply the desired value of load current. The noise contributed by the current source is very low in the entire current range. The fabrication of a low noise voltage preamplifier modified for bias dependent noise measurements and based on the existing design available in the MAT04 data sheet is also described.