Poly(amino acid)-facilitated electrochemical growth of metal nanoparticles

Poly(amino acids) are natural chelating agents for various metal ions. Zinc ions were encapsulated in situ in a conductive polypyrrole film using polyglutamic acid as a localized complexing agent within the film. The subsequent electrochemical reduction of the metal ions to zero-valent metal leads to the formation of the nanoparticles. The electrochemical approach demonstrated in this report provides facile regeneration of the particles and also prevents aggregation of nanoparticles in the conductive polymeric film. The correlation of the amount of zinc with the thickness of the film indicates that the zinc resides largely in the outer layer of the film. TEM and EDS data show that the nanoparticles formed are composed of zinc and are 18 +/- 7 nm in diameter. The nanoparticle/ polymer composite was used to reduce halogenated organics, indicating its potential usefulness in remediation applications.     

Ultrasensitive vapor detection with surface-enhanced Raman scattering-active gold nanoparticle immobilized flow-through multihole capillaries

We developed novel flow-through surface-enhanced Raman scattering (SERS) platforms using gold nanoparticle (Au-NP) immobilized multihole capillaries for rapid and sensitive vapor detection. The multihole capillaries consisting of thousands of micrometer-sized flow-through channels provide many unique characteristics for vapor detection. Most importantly, its three-dimensional SERS-active micro-/nanostructures make available multilayered assembly of Au-NPs, which greatly increase SERS-active surface area within a focal volume of excitation and collection, thus improving the detection sensitivity. In addition, the multihole capillary's inherent longitudinal channels offer rapid and convenient vapor delivery, yet its micrometer-sized holes increase the interaction between vapor molecules and SERS-active substrate. Experimentally, rapid pyridine vapor detection (within 1 s of exposure) and ultrasensitive 4-nitrophenol vapor detection (at a sub-ppb level) were successfully achieved in open air at room temperature. Such an ultrasensitive SERS platform enabled, for the first time, the investigation of both pyridine and 4-nitrophenol vapor adsorption isotherms at very low concentrations. Type I and type V behaviors of the International Union of Pure and Applied Chemistry isotherm were well observed, respectively.     

Analysis of colour strength,colour fastness and antimicrobial properties of silk fabric dyed with natural dye from red prickly pear fruit

In the present study, a natural dye is extracted from red prickly pear fruit (Opuntia ficus-indica) and is applied on the silk fabric using natural (myrobalan) and synthetic (copper sulphate) mordant. The dyeing of silk fabric is carried out using two different routes, namely, pre-mordanting and post-mordanting at different mordant concentrations and the dyed silk fabric was evaluated for its colour strength, colour fastness and antibacterial properties. The colour strength (K/S) was found to be higher in the post-mordant-processed fabric with the use of synthetic mordant compared to pre-mordanting and with the use of natural mordants and highest colour strength was observed at the mordant concentration of 6% and at a pH of 6 in all the cases. The colour fastness properties of the fabric also found to be improved in post-mordanting with use of synthetic mordants. The antimicrobial efficacy was also evaluated both in terms of zone of inhibition (qualitative analysis [SN195920]) and bacterial reduction % (quantitative analysis [AATCC 100]), against dyed silk fabric samples against on Staphylococcus aureus and Escherichia coli.     

Use of Friction Buttering for Overcoming HAZ Liquation Cracking

Multi-layer friction deposits in nickel-based superalloy Inconel 718 were investigated for their heat-affected zone liquation cracking resistance. The friction deposits, owing to their fine-grained microstructure with a large number of subgrain boundaries and fine, uniformly distributed carbide particles, were found to exhibit superior liquation cracking resistance to standard wrought-processed alloy 718. Based on these findings, a new technique involving friction deposition of the base plates prior to fusion welding was proposed for overcoming liquation cracking.     

Enhanced intestinal absorption and bioavailability of raloxifene hydrochloride via lyophilized solid lipid nanoparticles

The current oral therapy with raloxifene hydrochloride (RXH) is less effective due to its poor bioavailability (only 2%). Henceforth, an attempt was made to investigate the utility of triglyceride (trimyristin, tripalmitin and tristearin) based solid lipid nanoparticles (SLNs) for improved oral delivery of RXH. The SLN formulations prepared were evaluated for particle size, zeta potential and % entrapment and the optimized formulation was lyophilized. Solid state characterization studies unravel the transformation of RXH to amorphous or molecular state from the native crystalline form. Further the in situ perfusion studies carried out in rat intestine reveal the potential of SLN for enhanced permeation of raloxifene HCl across gastrointestinal barrier. To derive the conclusions, in vivo pharmacokinetic study was conducted in rats to assess the bioavailability of RXH from SLN formulation compared to drug suspension. Overall a twofold increase in bioavailability with SLN formulations confer their potential for improved oral delivery of RXH.     

Unification of MOS compact models with the unified regional modeling approach

This paper reviews the development of the MOSFET model (Xsim), for unification of various types of MOS devices, such as bulk, partially/fully-depleted SOI, double-gate (DG) FinFETs and gate-all-around (GAA) silicon-nanowires (SiNWs), based on the unified regional modeling (URM) approach. The complete scaling of body doping and thickness with seamless transitions from one structure to another is achieved with the unified regional surface potential, in which other effects (such as those due to poly-gate doping and quantum-mechanical) can be incorporated. The unique features of the Xsim model and the essence of the URM approach are described.     

Experimental and theoretical studies of anti-ulcer drugs with benzimidazole rings as corrosion inhibitor for copper in 1 M nitric acid medium

The adsorption effect of esomeprazole (ESP) and lansoprazole (LP) on corrosion behavior of copper in 1 M HNO₃ solution was investigated using potentiodynamic polarization, electrochemical impedance spectroscopy (EIS) and weight loss measurements. The experimental results indicate that both ESP and LP inhibited the corrosion of copper in nitric acid solution and the inhibition efficiency increased as the concentration of the compounds increased. EIS measurements confirmed that the charge transfer resistance increases on increasing the inhibitor concentration. Polarization measurements showed that the inhibitors are of mixed type. From the weight loss measurements, the inhibition efficiency of the inhibitors was found to vary with concentration, immersion time, and temperature. The adsorption of inhibitors on the copper surface follows Langmuir isotherm. The surface morphology was examined by scanning electron microscope and atomic force microscope. Further, the computational calculations are performed to find a relation between their electronic and structural properties.     

Optimization of plasma treatment variables to improve the hydrophilicity of polylinen® fabrics

Polylinen^® fabrics are obtained as a result of modification in the physical structure of polyester yarns to replicate the linen fabric. The scanning electron microscope analysis and Fourier transform infrared results reveal that the plasma treated fabric surface is effectively modified to enhance the wettability of the fabrics. In the present study, response surface methodology was employed to investigate the effects of different plasma treatment variables on the wetting behavior of polylinen fabrics. Box–Behnken design was used for the optimization of plasma treatment process and to evaluate the effects and interactions of the process variables, i.e. treatment time, power, and distance between the electrodes on the wettability of polylinen fabrics. The optimum conditions for maximum wicking height (4.3?cm) and spreading rate (86?s) of polylinen fabrics were established at 75?s treatment time, 460 watt power, and 2.5?cm distance between the electrodes. The plasma treated polylinen fabrics showed much better wettability in terms of wicking and spreading rate compared to untreated fabrics, which confirms that the modified structure of polylinen fabric and the plasma treatment influences the wettability of fabrics.     

Thermal characterisation study of ZrO2/water nanofluid

ABSTRACT

Nanofluids act as tough elements in future of coolants in thermal management systems. Nanofluids have a remarkable potential in the process of heat transfer augmentation, which is reported in various investigations conducted by researchers across the world. Nanofluids attracted many researchers and the progress in this field has been tremendous because of the high thermal properties and probable applications in some areas like aerospace, transportation industry, medical regions and also as micro electronics. These fluids are having conjoined properties of base fluid and nano particles. This current work reports the thermophysical properties of ZrO₂/water-based nanofluid. The synthesised nanoparticles have been characterised by scanning electron microscope and XRD techniques. The behaviour of thermal conductivity and viscosity of the ZrO₂/water-based nanofluid of various concentrations have been studied.