Effect of tin diffusion on the optical behavior of float glass in the soft-x-ray region

The optical responses of two sides of float glass in the soft-x-ray region were studied at the Indus-1 synchrotron facility. To the best of our knowledge these are the first experimentally obtained optical data for both sides of float glass in the soft-x-ray region. Optical constants delta and beta were determined by use of angle-dependent reflectance techniques in the wavelength range 80-200 A. On the side of the glass that was tin indiffused, a significant difference in delta value from that of the non-tin-side surface was observed. The measured data were compared with Henke's tabulated value of SiO2. The surface roughness of float glass was separately determined by hard-x-ray reflectivity to minimize the number of fitting variables. The effect of a contamination layer on the determination of optical constants was avoided by an appropriate sample-cleaning method.     

Characterization of interfacial and mechanical properties of “green” composites with soy protein isolate and ramie fiber

Environment-friendly fiber-reinforced composites were fabricated using ramie fibers and soy protein isolate (SPI) and were characterized for their interfacial and mechanical properties. Ramie fibers were characterized for their tensile properties and the parameters for the Weibull distribution were estimated. Effect of glycerol content on the tensile properties of SPI was studied. Interfacial shear strength (IFSS) was determined using the microbond technique. Based on the IFSS results and fiber strength distribution, three different fiber lengths and fiber weight contents (FWC) were chosen to fabricate short fiber-reinforced composites. The results indicate that the fracture stress increases with increase in fiber length and fiber weight content. Glycerol was found to increase the fracture strain and reduce the resin fracture stress and modulus as a result of plasticization. For 10% (w/w) of 5 mm long fibers, no significant reinforcement effect was observed. In fact the short fibers acted as flaws and led to reduction in the tensile properties. On further increasing the fiber length and FWC, a significant increase in the Young's modulus and fracture stress and decrease in fracture strain was observed as the fibers started to control the tensile properties of the composites. The experimental data were compared to the theoretical predictions made using Zweben's model. The experimental results are lower than the predicted values for a variety of reasons. However, the two values get closer with increasing fiber length and FWC.     

Optimization of Fenton-biological treatment scheme for the treatment of aqueous dye solutions

Degradation of dyes especially, azo dyes are difficult due to their complex structure and synthetic nature. The main objective of this study was to evaluate the Fenton-biological (aerobic) treatment train for decolorization and mineralization of azo dyes viz. Reactive Black 5 (RB5), Reactive Blue 13 (RB13) and Acid Orange 7 (AO7). The objective of Fenton treatment was only to decolorize the dyes (breakage of -NN-), as it was considered that after breakage of -NN-, the dyes will become amenable to biodegradation and can be further treated in aerobic biological system. Hence studies were carried out to optimize the lower Fenton's doses for decolorization of dyes. The optimum doses for decolorization (>95%) of all the three dyes were found out to be 15 mgL(-1) of Fe(2+) (0.27 mM) and 50 mgL(-1) (1.47 mM) of H(2)O(2) dose at optimum pH 3. Further it was also investigated that at lower doses, the main problem of Fenton process (sludge generation) can also be minimized. Later the mineralization of the dye (removal of aromatic amines) was achieved in the aerobic biological treatment system. Overall reduction of 64, 89 and 75% in the aromatic amines (at 254 nm), 88, 95 and 78% in naphthalene ring associated compounds (near 310 nm) and 49, 89 and 91% reduction in benzene ring associated compounds (near 226 nm) were observed for RB5, RB13 and AO7, respectively. Thus this treatment system seems to be quite effective and economical option for the treatment of recalcitrant compounds like dyes, as the cost in the chemical treatment is considered mainly due to chemicals thus at lower doses the operational cost is saved. Further, as the sludge generation was almost negligible at lower doses, thus the savings in cost of handling and disposal of hazardous sludge also adds to economy of treatment.     

Prospects of manufacturing organic semiconductor-based integratedcircuits

The driving force for developing organic thin-film transistor (OTFT)-based electronics is the fact that they are flexible, lightweight and have the prospect of low-cost manufacturing. Major barriers in the practical realization of OTFT-based electronic systems are the need for larger power supplies, lower gain, lower switching speeds and reliability problems. New directions leading to changes in the design of transistors, materials used in the fabrication, and processing techniques are warranted for developing process and equipment that can lead to the manufacturing of OTFT-based electronics. For developing dense OTFT-based electronics, the low thermal conductivity (as compared to silicon) of organic semiconductors is a fundamental problem. The use of nanodimension polymers with homogeneous microstructure, transistors operating in subthreshold region and the use of new materials (high and low dielectric constant dielectric materials as well as Cu as the conductor for interconnections) for fabricating transistors and a novel rapid photothermal processing technique for depositing thin films of organic semiconductors as well as for reducing the defects introduced during processing are some of the proposed directions that may lead to the manufacturing of OTFT based electronics     

Pulsed laser ablated off-stoichiometric thin films of the Heusler alloy Co2TiSn on Si (100) substrate

We report the growth of thin films of ferromagnetic Heusler alloy Co₂TiSn on Si (100) substrate using KrF excimer pulsed laser ablation. Films of thicknesses ranging from 8 to 220 nm were deposited on Si (100) substrate heated up to 200 ± 10 °C, with an aim to study the structural, morphological and magnetic properties. The grown films are off-stoichiometric, polycrystalline, having single-phase with high degree of (220) texturing. Angle dependent fluorescence measurements suggest no segregation of alloying elements as a function of depth. X-ray reflectivity measurements indicate that all the films are having low density layer at the top as well as at the film-substrate interface. Magneto optical Kerr effect measurements at room temperature reveal clear hysteresis loops suggesting ferromagnetic behavior of the films. Thermal annealing at temperature ≥ 220 °C suggest transformation of Co₂TiSn phase into cobalt silicide phase, which confirms the necessity of low substrate temperature (< 220 °C) to produce such single-phase Co₂TiSn films.     

Influence of highly dispersible silica filler on the physical properties,tearing energy,and abrasion resistance of tire tread compound

Rubber industry is facing a stiff challenge in the years to come. There are rising price for fossil fuel and shortage of resources. There is more stringent legislation to protect the environment and reduce the emission. Filler plays an important role in imparting useful properties to rubber products. In this article, the effects of new generation filler, on the physical properties, tearing energy, and abrasion resistance were investigated. The new generation filler, highly dispersible silica, has a dibutyl phthalate (DBP) absorption value of more than 180cc 100 g⁻¹, more branched structure and relatively higher amount of small aggregates. Four different loadings of silica (up to 45 phr) were investigated. With increasing filler loading, the tensile strength and modulus at 300% elongation increased and the elongation-at-break decreased. The rebound resilience decreased and tan delta value improved with increasing silica content. The abradability continuously decreased with concomitant increase in the side coefficient force. The fatigue resistance was found to be better at higher silica loading. The silica particles due to its surface structure helps in crack arresting. The abradibility was related to tearing energy, loss modulus, and breaking energy. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 47560.     

Development of high aspect ratio X-ray parabolic compound refractive lens at Indus-2 using X-ray lithography

A synchrotron beamline dedicated to soft and deep X-ray lithography is operational on Indus-2 synchrotron source and is being used for high aspect ratio microfabrication. This X-ray lithography facility provides the access to X-ray mask fabrication, X-ray exposures and development of micro-nano structures. We report the development of planar parabolic refractive X-ray lenses in SU-8 for energy range 8–20 keV using this facility. The focussing properties of X-ray lenses were studied with synchrotron radiation in the X-ray energy range 8–20 keV on the moderate emittance machine Indus-2. A focal spot of 11 μm at 15.9 keV is obtained with a gain of 18.     

Fabrication of high aspect ratio comb-drive actuator using deep X-ray lithography at Indus-2

We report microfabrication of high aspect ratio comb-drive using deep X-ray lithography at Indus-2 synchrotron radiation source. Analysis shows that the comb-drive actuator of aspect ratio 32 will produce nearly 2.5 μm displacement when 100 V DC is applied. The displacement increases as the gap between the comb finger decreases. For fabrication of comb-drive, polyimide–gold X-ray mask using UV lithography is made for the first time in India. To pattern on an 800 μm thick X-ray photoresist (PMMA) exposures are performed using our deep X-ray lithography beamline (BL-07) at Indus-2. Metallization on the selective regions of the developed X-ray photoresist with comb-drive pattern was carried out by RF sputtering. Following this the comb-drive actuator of PMMA was fabricated by one-step X-ray lithography. The comb-drive can also be used as a sensor, energy harvester, resonator and filter.