Solidification and microstructural aspects of laser-deposited Ni-Mo-Cr-Si alloy on stainless steel

Laser cladding of stainless steel substrate was carried out using Ni-32Mo-15Cr-3Si (wt%) alloy powder. Laser cladding parameters were optimized to obtain defectfree and metallurgically bonded clad. Variation in solidification rate, cooling rate and compositional variation resulted in heterogeneous microstructure. Microstructure was found to be distinctly different in regions of clad cross-section. Majority of the region was found to consist of eutectic of Mo-rich hcp intermetallic Laves phase and NiFe fcc gamma solid solution phases. Extensive microstructural examinations of different clad regions have been carried out using microscopy and microanalysis techniques.     

Preparation and electrochemical characterization of a new NiMoO4 catalyst for electrochemical O2 evolution

The NiMoO₄ catalyst has been obtained by a precipitation method under a controlled pH condition and characterized ex situ by infrared, X-ray diffraction, Brunauer–Emmett–Teller (BET), and particle size, and in situ by cyclic voltammetry, impedance and steady-state anodic Tafel polarization techniques. Results show that NiMoO₄ has pure crystalline monoclinic phase with the crystallite size ~50 nm and the lattice constants, a?=?9.597 Å, b?=?8.765 Å, c?=?7.667 Å, and β?=?114.22°. Values of the average particle size and BET surface area of the oxide powders are found to be 730 nm and 11.75 m²/g, respectively. The oxygen evolution reaction follows the first-order kinetics with respect to OH^? concentration, the Tafel slope being ~70 mV.     

Kinetics and mechanism of the ruthenium(III)-catalysed oxidation of aminoalcohols by alkaline hexacyanoferrate(III)

Summary The kinetics of the ruthenium(III)-catalysed oxidation of aminoalcoholsviz. 2-aminoethanol and 3-aminopropanol by alkaline hexacyanoferrate(III) has been studied spectrophotometrically. The reactions are rapid initially, then follow a second order rate dependence with respect to each of the catalyst and the oxidant. The second order rate dependence with respect to ruthenium(III) was observed for the first time. The order in [Aminoalcohol] and [OH^–] is unity in each case. A suitable mechanism, consistent with the observed kinetic data is postulated.     

Eggshell Nanosheets: Synthesis,Properties, and Their Forensic Applications in Latent Friction Ridges Development

Since waste materials are used to identify, individualize, and evaluate evidence like fingerprints, palmprints, footprints, etc. that are found at a crime scene, they have a substantial impact on the field of forensic science. Many waste powders have recently been employed in fingerprint recognition. Nanosheets made up of eggshells have been put forward as an application in friction ridge development. Eggshell is a biochemical substance made up of chemical compounds like calcium carbonate, which is considered as a waste product. For the formation of an eggshell nanosheet (ESN), shells are dried and crushed into a fine powder and to get this powder in the form of a nanosheet, the Ball milling technique is used. The synthesis of pure ESN is confirmed by Scanning Electron Microscopy (SEM) and X-ray diffraction (XRD) techniques. The size of nanosheets ranged from 30 to 90 nm as shown in SEM images. Developed powder is then used for the application of fingerprint development and it provides excellent results on all porous, non-porous, and semi-porous surfaces. Thus, this newly synthesized ESN powder can be used as a significant powder method in latent fingerprint technology.     

Direct evidence for charge ordering and electronic phase separation in BixSr1−xMnO3 at room temperature

We present a study of charge ordering and electronic phase separation (EPS) phenomenon in Bi_xSr_1−xMnO₃, for an exhaustive range of x (0.25x0.75), by STM/STS at room temperature (RT) and specific heat measurements at high temperatures (350–650 K). Atomically resolved STM images of the samples, in real space, show the presence of stripe-like charge-ordered (CO) phase coexisting with charge-disordered (CD) phase. The STM images further reveal that the fraction of CO phase increases with an increase in x. The conductance spectra of these phases measured at nano level by STS are discussed. The transition to CO phase above RT is corroborated by specific heat measurements in all samples, giving a T_CO(x) phase diagram for this system.     

On associative curves. I

Acta Mathematica Hungarica -     

Impact of rice crop residue burning on levels of SPM,SO2 and NO2 in the ambient air of Patiala (India)

Ground-based ambient air monitoring was conducted at five different locations in and around Patiala city (29°49′–30°47′N Latitude, 75°58′–76°54′E Longitude) in Northern India in order to determine the impact of open burning of rice (Oriza sativa) crop residues on concentration levels of suspended particulate matter (SPM), sulphur dioxide (SO₂) and nitrogen dioxide (NO₂). Covering sensitive, residential, agricultural, commercial and urban areas, sampling of these pollutants was organised during August 2006 to January 2007 and August 2007 to January 2008 casing two rice crop residue burning periods (October–November) using a high volume sampling technique combined with gaseous sampling systems. Gravimetric analysis was used in the estimation of total suspended particulate matter (TSPM) whereas SO₂ and NO₂ concentration was determined using spectrophotometer (Specord205, Analytikjena). Monthly average concentrations of SPM, SO₂ and NO₂ have shown significant up and down features at all the selected sampling sites during the study period. Monthly average concentrations (24 hour) of SPM, SO₂ and NO₂ varied from 100 ± 11 µg m^?3 to 547 ± 152 µg m^?3, 5 ± 4 µg m^?3 to 55 ± 34 µg m^?3 and 9 ± 5 µg m^?3 to 91 ± 39 µg m^?3. Substantially higher concentrations were recorded at the commercial area site as compared to the other sampling sites for all the targeted air pollutants. Levels of SPM, SO₂ and NO₂ showed clear increase during the burning months (October–November) incorporated with the effect of meteorological parameters especially wind direction, precipitation and atmospheric temperature.     

Crystal structure of Alanine‐Copper(II) complex to understand the mechanism of salt induced prebiotic oligomerization of amino acids

Oligomerization of amino acid monomers is the vital step in the formation of longer peptides and functional proteins. In spite of continuing efforts towards solving the puzzle of origin of life, the mystery of chemical evolution remains unsolved. Out of various pathways proposed for the formation of peptides under prebiotic conditions, salt induced peptides synthesis presents the most plausible scenario. In attempts to study mechanism of prebiotic oligomerization of amino acid on primitive earth the current study was aimed to determine the crystal structure of intermediate copper amino acid complex and its supra‐molecular assembly. The Structure of the copper alanine complex obtained from SIPF was studied by x‐ray crystallography. The self‐assembling properties of complex into supra‐molecular nanostructures were studied using Field‐emission electron microscopy (FE‐SEM). Results showed the occurrence of racemization of amino acids. This is the first structural study for copper alanine complex formed from prebiotic peptide synthesis pathway. The aggregational properties of intermediate complex showed the formation of rod like crystals and nanospheres. The findings from our study showed the possible mechanism of prebiotic oligomerization of amino acids on the primitive earth towards formation of longer peptides and functional proteins.     

Quintic trigonometric spline based numerical scheme for nonlinear modified Burgers' equation

This paper presents a numerical method based on quintic trigonometric B‐splines for solving modified Burgers' equation (MBE). Here, the MBE is first discretized in time by Crank–Nicolson scheme and the resulting scheme is solved by quintic trigonometric B‐splines. The proposed method tackles nonlinearity by using a linearization process known as quasilinearization. A rigorous analysis of the stability and convergence of the proposed method are carried out, which proves that the method is unconditionally stable and has order of convergence O(h⁴ + k²). Numerical results presented are very much in accordance with the exact solution, which is established by the negligible values of L₂ and L_∞ errors. Computational efficiency of the scheme is proved by small values of CPU time. The method furnishes results better than those obtained by using most of the existing methods for solving MBE.