Excitation functions of (n,p) reactions for stable isotopes of Cr,Fe and Ni from threshold to 20 MeV

The excitation functions of (n,p) reactions for the stable isotopes of Cr, Fe and Ni were calculated using EMPIRE 3.0 β1 (ARCOLE) from threshold to 20 MeV. The cross-sections are calculated using full featured Hauser–Feshbach statistical model with pre-equilibrium effects by invoking DEGAS option in the code. A good agreement between the calculated and experimental data (EXFOR data base) as well as evaluated data is obtained with option of neutron and proton potentials by Koning (Global) and HFB parity dependent nuclear level density. This is an important step to the validation of nuclear model with superior predictive power. The compound nucleus and pre-equilibrium reaction mechanisms as well as the isotopic effects were also studied.     

Studies on colorimetry,solubility and thermodynamic properties of Copper Soap Solutions

The colorimetric method for the estimation of metal content in non-aqueous copper soap solutions is more reliable than the method of chemical analysis particularly in dilute soap solutions. The behaviour of the copper soaps in organic media is quite different from that of the copper salts and they exhibit absorption maxima at different wavelengths. The solubility measurements at different temperatures and the values of apparent heat of solution confirm the existence of micellar aggregates above the KRAFFT point. The numerical values of the temperature coefficient of E. M. F. of the cells Cu/CuD₂(s), LiD(c), AgD(s)/Ag and ΔG, ΔH and ΔS for the cell reactions decrease with the increase in the chainlength of the acid (D) in the soap. The E. M. F. of the cell is independent of the concentration of the lithium soap solution.     

Tailoring the spring constant of Si nanorod structures using swift heavy ion irradiation

This study reports a post-deposition technique of engineering the mechanical properties of cantilever-like silicon nanorods by using swift heavy ion irradiation. Slanted silicon nanorods grown by glancing angle deposition technique on a patterned Si(1 0 0) substrate are irradiated by 100 MeV Ag⁺⁸ ions at a fluence of 10¹⁴ ions cm^?2. The average spring constant (k) of the nanorods determined by force–distance spectroscopy reduces to 65.6 ± 20.8 Nm^?1 post-irradiation as compared to 174.2 ± 26.5 Nm^?1 for pristine nanorods. Scanning electron micrographs show bending of the Si nanorods after irradiation. Micro-Raman and high-resolution transmission electron microscope studies on pristine and irradiated Si nanorods confirm the transformation of nanocrystalline regions present in pristine nanorods to amorphous phase on irradiation. This structural transformation and bending of the nanorods are responsible for the observed changes in the mechanical properties post-irradiation. The technique offers a simpler possibility of tailoring mechanical properties of nanostructures post-deposition by ion irradiation.     

Pharmacophore mapping of arylbenzothiophene derivatives for MCF cell inhibition using classical and 3D space modeling approaches

Considering the worth of developing non-steroidal estrogen analogs, the present study explores the pharmacophore features of arylbenzothiophene derivatives for inhibitory activity to MCF-7 cells using classical QSAR and 3D space modeling approaches. The analysis shows that presence of phenolic hydroxyl group and ketonic linkage in the basic side chain of 2-arylbenzothiophene core of raloxifene derivatives are crucial. Additionally piperidine ring connected through ether linkage is favorable for inhibition of breast cancer cell line. These features for inhibitory activity are also highlighted through 3D space modeling approach that explored importance of critical inter features distance among HB-acceptor lipid, hydrophobic and HB-donor features in the arylbenzothiophene scaffold for activity.     

Potassium sorbate as an inhibitor in copper chemical mechanical planarization slurry. Part I. Elucidating slurry chemistry

The integration of an advanced inhibitor, potassium sorbate (K[CH₃(CH)₄CO₂]), in a copper CMP slurry based on hydrogen peroxide and glycine is reported. The first part of the study discusses the slurry chemistry by qualitatively describing the processes involved and proposes a mechanism for a hydrogen peroxide-glycine based slurry having sorbate anion as an inhibitor. For this purpose, the specific role of each chemical constituent in the slurry was elucidated at a fundamental level by electrochemical studies, X-ray photon spectroscopy (XPS) and contact angle measurements, all linked to the CMP performance on blanket wafers. Once the polishing mechanism was resolved the influence of the inhibitor was evaluated by CMP processing of patterned wafers.     

Adsorptive removal of heavy metals from aqueous solution by treated sawdust (Acacia arabica)

The removal of Cr(VI), Pb(II), Hg(II) and Cu(II), by treated sawdust has been found to be concentration, pH, contact time, adsorbent dose and temperature dependent. The adsorption parameters were determined using both Langmuir and Freundlich isotherm models. Adsorption capacity for treated sawdust, i.e. Cr(VI) (111.61 mg/g), Pb(II) (52.38 mg/g), Hg(II) (20.62 mg/g), and Cu(II) (5.64 mg/g), respectively. Surface complexation and ion exchange are the major removal mechanisms involved. The adsorption isotherm studies clearly indicated that the adsorptive behaviour of metal ions on treated sawdust satisfies not only the Langmuir assumptions but also the Freundlich assumptions. The applicability of Lagergren kinetic model has also been investigated. The adsorption follows first-order kinetics. Thermodynamic constant (k_ad), standard free energy (ΔG°), enthalpy (ΔH°) and entropy (ΔS°) were calculated for predicting the nature of adsorption. The percentage adsorption increases with pH to attain a maximum at pH 6 and thereafter it decreases with further increase in pH. The results indicate the potential application of this method for effluent treatment in industries and also provide strong evidence to support the adsorption mechanism proposed.     

Catalytic activity of platinum-cobalt alloy nanoparticles decorated functionalized multiwalled carbon nanotubes for oxygen reduction reaction in PEMFC

The role of functionalized multiwalled carbon nanotubes (MWNTs) decorated with platinum nanoparticles (Pt/f-MWNTs) and platinum-cobalt alloy nanoparticles (Pt₃Co/f-MWNTs) has been investigated for oxygen reduction reaction (ORR) in a proton exchange membrane fuel cell. The electrocatalysts are synthesized by a conventional sodium borohydride reduction method and modified polyol reduction method. The modified polyol reduction method yields better uniform dispersion, higher loading and optimum particle size of Pt and Pt₃Co alloy nanoparticles over the MWNTs compared to the conventional sodium borohydride reduction method. The electrochemical surface area of the electrocatalysts is calculated using cyclic voltammetry. Pt₃Co/f-MWNTs synthesized via modified polyol reduction method yield the highest performance with a maximum power density of 798 mW cm⁻² at 60 °C without any back pressure. The enhanced catalytic activity of Pt₃Co/f-MWNTs toward ORR is attributed to uniform dispersion and optimum particle size of Pt₃Co alloy nanoparticles over the surface of f-MWNTs.