Chronic arsenicosis in cattle with special reference to its metabolism in arsenic endemic village of Nadia district West Bengal India

Thirty Milch cattle were selected randomly from a village of Nadia district of West Bengal, India containing high arsenic in water and soil samples. Milk, feces and hair samples were collected to analyze arsenic status in animals. Water and straw samples were also estimated for arsenic. Milk products prepared from milk of cattle rearing in arsenic prone village were also collected to quantify total arsenic and speciation of arsenic in milk and feces samples were also carried out. It was observed that high amount of arsenic was present in milk, feces, hair of cattle and water and straw samples in arsenic prone village. Milk product also contained significant amount of arsenic than that of milk product of control village. Speciation study revealed arsenite fraction was mainly eliminated through milk, whereas organoarsenic species were mainly excreted through feces.     

Hydrogen permeation resistant glass-ceramic coatings for gamma-titanium aluminide

Hydrogen embrittlement is no doubt a limiting factor in the high performance applications of many intermetallics. This is mainly because of the inward diffusion of hydrogen atoms and formation of brittle hydride phases during hydrogen exposure of the intermetallic components that resulted in lowering the component's ductility and fracture toughness. γ-TiAl intermetallic is not an exception in this regard. The present study dealt with the method of providing oxide based glass-ceramic coatings on the surface of γ-TiAl by vitreous enameling technique to protect the substrate from the detrimental effect of hydrogen at high temperatures like 800 °C at 0.1 MPa gas pressure for up to 75 h. Results showed that although the uncoated γ-TiAl alloy was severely affected by the hydrogen exposure test, the coated samples were remained mostly unaffected after the test with minimum changes in their microstructure. While the gain in weight of the uncoated alloy after 75 h of H₂ permeation test was ~ 1.05 mg/cm², the weight gain of the two coated samples were only ~ 0.12 mg/cm² for BaO-SiO₂-MgO and ~ 0.15 mg/cm² for MgO-SiO₂-TiO₂ glass-ceramic coated substrates. As revealed from the XRD phase analysis, after the high temperature exposure of the coated samples in flowing H₂ for up to 75 h, the coated layers were only enriched with their major crystalline phases with little or no trace of the detrimental hydride phases, whereas, in the uncoated alloy, presence of aluminum hydride and titanium hydrides were observed.     

Low-pressure pneumatic muscles: development,phenomenological modeling,and evaluation in assistive applications through sEMG analysis

Compliant actuators have received much attention from researchers over the last two decades. Specifically, pneumatic artificial muscles (PAMs) have been used in several human-in-loop assistive and rehabilitative devices due to their inherent behavior resembling biological muscles. We presented a lucid customizable fabrication process to develop low-pressure actuated PAMs, named pneumatic silicone tube artificial muscles (pSTAMs), and to cater activity-specific actuator requirements. Two constructions of pSTAMs with varying lengths were rigorously experimented at different pressure-load conditions for their isobaric static and stiffness characterizations. Estimation of bandwidth and use of empirical correction factors in the conventional analytical models for quasi-static characterization of pSTAMs were demonstrated. Lumped parameter-based phenomenological model was employed to closely model their dynamic characteristics. A detailed integrated electromyography analysis with surface electromyography signals from the targeted muscle groups was performed to determine the efficacy of using pSTAMs in two activities.

     

Development of high-voltage pulse-slicer unit with variable pulse duration for pulse radiolysis system

A high-voltage pulse-slicer unit with variable pulse duration has been developed and integrated with a 7 MeV linear electron accelerator (LINAC) for pulse radiolysis investigation. The pulse-slicer unit provides switching voltage from 1 kV to 10 kV with rise time better than 5 ns. Two MOSFET based 10 kV switches were configured in differential mode to get variable duration pulses. The high-voltage pulse has been applied to the deflecting plates of the LINAC for slicing of electron beam of 2 μs duration. The duration of the electron beam has been varied from 30 ns to 2 μs with the optimized pulse amplitude of 7 kV to get corresponding radiation doses from 6 Gy to 167 Gy.     

Behavior of cellulose liquefaction after pretreatment using ionic liquids with water mixtures

Ionic liquid (IL)‐water mixtures were applied in cellulose pretreatment experiment and the pretreated cellulose was used in subsequent phenol liquefaction process as a new application method. Cellulose recovery rate and the average molecular weight (M_w) of pretreated cellulose were investigated to understand the influence of these mixtures on cellulose structure. X‐ray diffraction, Fourier transform infrared, gel permeation chromatograph, and scanning electron microscope were used to clarify the changes of pretreated cellulose. The liquefied residues from untreated cellulose and pretreated cellulose were considered as significant index to determine the effect of IL‐water mixtures on cellulose. Moreover, liquefied residues were initially characterized by the variation of the average M_w. It was suggested that the lower M_w of cellulose obtained in IL‐water mixtures, and the crystalline structure was disrupted. So, some cracks were found on the cellulose surface obviously. The liquefied residues result suggested that the pretreated cellulose obtained the lower residues at the same time or the same amount of residues by using the less time. The behavior of cellulose liquefaction efficiency using IL‐water mixture pretreatment was discussed. The lower M_w of cellulose was the major factor, which accelerates the cellulose phenol liquefaction process efficiency. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40255.     

In situ synthesis,fabrication and Rietveld refinement of the hydroxyapatite/titania composite coatings on 316 L SS

The development of Hydroxyapatite (HAP)/Titania (TiO₂) composite coatings on metallic implants have received a great deal of attention during the recent years owing to their superior advantages in biomedical applications. The present study has focused on the in situ formation of HAP/TiO₂ composite powders through aqueous precipitation technique. Five different HAP/TiO₂ composite powders of varied HAP to TiO₂ ratios has been synthesized in the present study and the results were compared with the stoichiometric HAP, Rutile TiO₂ and Anatase TiO₂ which also have been synthesized by adapting a similar synthetic procedure. All the synthesized powders have been analyzed using X-ray diffraction (XRD) and X-ray fluorescence (XRF) techniques. Rietveld Refinement technique has been employed to generate quantitative information about the structural characteristics and phase content in all the powder samples. Further, the electrophoretic deposition (EPD) method has been employed to fabricate HAP/TiO₂ composite coatings on 316 L SS and the resultant coatings were analyzed for its quantitative structural characteristics. The results from the present investigation has confirmed that concentration of TiO₂ in the HAP/TiO₂ composites and heat treatment temperatures have played a major role in the degradation of HAP to β-Tricalcium phosphate and also in the conversion of Anatase to Rutile TiO₂ phase.     

Etched multimode microfiber knot-type loop interferometer refractive index sensor

We propose a novel refractive index sensor based on multimode microfiber knot-type loop (NL) interferometer. The middle portion (~5 cm) of a 15 cm long multimode fiber is etched in 48% hydrofluoric acid to reduce its diameter to ~12 μm. A NL of diameter <1 mm is made from the etched fiber. The ends of etched fiber are spliced with single-mode fibers for launching and detecting light from the NL interferometer. The NL introduces path differences to produce interferometric spectra with free spectral range ~16 nm. The spectrum shifts as the surrounding refractive index of the loop is changed by adding chemicals. We observe the highest sensitivity of the NL interferometer ~172 nm/RIU (refractive index unit) at a refractive index value 1.370 as obtained experimentally using commonly available chemicals. The design could be used as simple, low cost, and highly sensitive biological and chemical sensor.     

Combined optical and acoustical method for determination of thickness and porosity of transparent organic layers below the ultra-thin film limit

Analysis techniques are needed to determine the quantity and structure of materials composing an organic layer that is below an ultra-thin film limit and in a liquid environment. Neither optical nor acoustical techniques can independently distinguish between thickness and porosity of ultra-thin films due to parameter correlation. A combined optical and acoustical approach yields sufficient information to determine both thickness and porosity. We describe application of the combinatorial approach to measure single or multiple organic layers when the total layer thickness is small compared to the wavelength of the probing light. The instrumental setup allows for simultaneous in situ spectroscopic ellipsometry and quartz crystal microbalance dynamic measurements, and it is combined with a multiple-inlet fluid control system for different liquid solutions to be introduced during experiments. A virtual separation approach is implemented into our analysis scheme, differentiated by whether or not the organic adsorbate and liquid ambient densities are equal. The analysis scheme requires that the film be assumed transparent and rigid (non-viscoelastic). We present and discuss applications of our approach to studies of organic surfactant adsorption, self-assembled monolayer chemisorption, and multiple-layer target DNA sensor preparation and performance testing.     

A novel method of determination of wire lag for enhanced profile accuracy in WEDM

Wire bending due to gap force is a major cause of imprecision in WEDM applications. To achieve higher precision and accuracy the knowledge of gap force and wire lag is extremely essential. In the present research, an in depth study on wire lag phenomenon has been carried out. A novel method to measure gap force intensity and wire lag under any given machining condition has been proposed by developing an analytical model. Experiments were carried out to verify the proposed model. Beside this, the impact of wire deflection on profile accuracy during cutting cylindrical job has been investigated. Based upon the developed analytical model an effective method has been proposed to eliminate this inaccuracy using wire lag compensation technique. The research finding will lead to better understanding of the gap force phenomena and will promote significant development in the domain of high precision WEDM.     

A self-synchronized ADALINE network for on-line tracking of power system harmonics

This paper presents a modified adaptive linear neuron (ADALINE) structure, called self-synchronized adaptive linear neuron (S-ADALINE) network for fast and accurate estimation of power system harmonics. The proposed network relies on the Levenberg gradient descent (LGD) method based parameter updating rule and is capable of dealing with both nominal and off-nominal frequency conditions, rather than the existing modified Widrow-Hoff delta rule based ADALINE network which provides good accuracy only at nominal frequency. Moreover, the S-ADALINE provides faster response and better noise immunity than the conventional approach. The only flaw of the proposed network is its high computational load. Based on simulation studies, performances of the proposed harmonic estimator at different operating conditions have been presented and its accuracy and response time have been compared with the conventional ADALINE structure.