16 research outputs found

    Advanced numerical scheme and its convergence analysis for a class of two-point singular boundary value problems.

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    [EN]In this article, a novel approach based on the shooting projection method and the Legendre wavelet operational matrix formulation for approximating a class of two-point SBVPs with Dirichlet and Neumann–Robin boundary conditions is proposed. For the new approach, an initial guess is postulated in contrast to the boundary conditions in the first step. The second step deals with the usage of the Legendre wavelet operational matrix method to solve the initial value problem (IVP). Further, the resulting solution of the IVP is utilized at the second endpoint of the domain of a differential equation in a shooting projection method to improve the initial condition. These two steps are repeated until the desired accuracy of the solution is achieved. To support the mathematical formulation, a detailed convergence analysis of the new approach is conducted. The new approach is tested against some existing methods such as various types of the variational iteration method, considering several numerical examples to which it provides high-quality solutions

    NEW APPROACH BASED ON COLLOCATION AND SHIFTED CHEBYSHEV POLYNOMIALS FOR A CLASS OF THREE-POINT SINGULAR BVPS.

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    [EN]In the recent decades, variety of real-life problems arises in astrophysics have been mimic using the class of three-point singular boundary value problems (BVPs). Finding an effective and accurate approach for a class of three-point BVPs is still a difficult problem, though. The goal of this paper is to design a numerical strategy for approximating a class of three-point singular boundary value problems using the collocation technique and shifted Chebyshev polynomials. Utilizing shifted Chebyshev polynomials, the problem is reduced to a matrix form, which is then converted into a system of nonlinear algebraic equations by employing the collocation points. The key advantages of the new approach are (a) it is a straightforward mathematical formulation, which makes it effortless to code, and (b) it is easily adaptable to solve various classes of three-point singular boundary value problems. The convergence analysis is carried out to ensure the viability of the proposed scheme

    NMR structure of an acyl-carrier protein from Borrelia burgdorferi

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    The high-resolution NMR structure of the acyl-carrier protein from the pathogen B. burgdorferi determined to a r.m.s. deviation of 0.4 Å over the protein backbone is reported. The NMR structure was determined using multidimensional NMR spectroscopy and consists of four α-helices and two 310-helices. Structural comparison reveals that this protein is highly similar to the acyl-carrier protein from A. aeolicus

    Characterization Studies on Lead-Zinc Tailings from Rampura-Agucha Mines

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    The process tailings of base metal industries contain considerable amounts of acid generating 'pyrite and sul-fides of other minerals. The recovery of sulfide minerals from the tailings not only will have environmental advan-tage but will also result in conservation of mineral wealth.For any such recovery activity, it is essential to characterize the tailings for physical, chemical and mineralogical characteristics. In the present study, typi-cal lead-zinc tailings sample from the operating plant at Rampura-Agucha mines of Hindustan Zinc Limited was collec-ted and characterized for size distribution, size by size chemical composition and mineral phase analysis through X-ray diffraction method. The size-by-size metal contents indicated increasing levels of silver and pyrite with decreasing particle size and the lead and zinc bearing minerals are segregated at relatively coarser size fract-ions. Microscopic studies of the coarser fractions have indicated that the lead and zinc minerals are in unliber-ated form. The XRD study has indicated that quartz is the major mineral phase followed by pyrite, sphalerite, galena and silver. The overall tailings sample was found to cont-ain 19.41% of pyrite, 2.02 % of zinc, 0.69 % lead, and 26.94 ppm of silver contents

    MGS Studies for Recovering Iron and Silver Values from Lead-Zinc Tailings

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    In mineral processing plants valuable minerals are recovered by rejecting gangue materials through various physical processing techniques to produce high-grade concentrate. However, after processing these ores, the tailings generated contain considerable amount of valua-bles because of inefficient of process plant or due to fluctuations in the mineralogical composition of the ore. Therefore, recovery of these valuable minerals is prerequisite from environmental and mineral conservation point of views

    Dip coating of forsterite-hydroxyapatitie-poly (ɛ-caprolactone) nanocomposites on Ti6Al4Vsubstrates for its corrosion prevention

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    522-528Titanium and titanium alloys are extensively used in biomedical, cardiac and cardiovascular applications for their superb properties, such as good fatigue strength, low modulus, machinability, formability, corrosion resistance and biocompatibility. However, titanium and its alloys do not meet the majority of all clinical necessities. Due to these reasons, surface modification is frequently performed to enhance the mechanical, biological and chemical properties of titanium and alloys. In this work, nanocomposites coating of poly(ɛ-caprolactone)/hydroxyapatite/forsterite (PCL/HA/F) have been successfully deposited on the Ti6Al4V substratesby dip coating at room temperature. The coatings are prepared with various concentrations of forsterite/hydroxyapatite nanopowder (2, 4, 6 and 8 wt.%) with a fixed concentration of PCL (4 wt.%) and thus coated Ti6Al4V substrates are examined for corrosion resistance. PCL/Hydroxyapatite/Forsterite coatings are characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM), which clearly showed the formation of nanocomposites. Potentiodynamic polarization curves and electrochemical impedance spectroscopy (EIS) are used to investigate corrosion behavior of the coated substrates, which portrayed that the composite coating of PCL/HA/F substantially enhanced the corrosion resistance of Ti6Al4V alloy

    Dip coating of forsterite-hydroxyapatitie-poly (ɛ-caprolactone) nanocomposites on Ti6Al4Vsubstrates for its corrosion prevention

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    Titanium and titanium alloys are extensively used in biomedical, cardiac and cardiovascular applications for their superb properties, such as good fatigue strength, low modulus, machinability, formability, corrosion resistance and biocompatibility. However, titanium and its alloys do not meet the majority of all clinical necessities. Due to these reasons, surface modification is frequently performed to enhance the mechanical, biological and chemical properties of titanium and alloys. In this work, nanocomposites coating of poly(ɛ-caprolactone)/hydroxyapatite/forsterite (PCL/HA/F) have been successfully deposited on the Ti6Al4V substratesby dip coating at room temperature. The coatings are prepared with various concentrations of forsterite/hydroxyapatite nanopowder (2, 4, 6 and 8 wt.%) with a fixed concentration of PCL (4 wt.%) and thus coated Ti6Al4V substrates are examined for corrosion resistance. PCL/Hydroxyapatite/Forsterite coatings are characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM), which clearly showed the formation of nanocomposites. Potentiodynamic polarization curves and electrochemical impedance spectroscopy (EIS) are used to investigate corrosion behavior of the coated substrates, which portrayed that the composite coating of PCL/HA/F substantially enhanced the corrosion resistance of Ti6Al4V alloy

    Complete backbone assignment of a Ca<SUP>2+</SUP>-binding protein of the βγ-crystallin superfamily from Methanosarcina acetivorans, at two denaturant concentrations

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    We report here almost complete backbone assignment of a Ca2+-binding protein of the &#946;&#947;-crystallin superfamily from Methanosarcina acetivorans, at two denaturant (GdmCl) concentrations, using double and triple resonance experiments. These NMR assignments will be useful to understand the unfolding path of this protein
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