3,599 research outputs found

    A finite-element alternating method for two-dimensional Mode-1 crack configurations

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    A finite-element alternating method is presented for 2-D Mode-1 crack problems. An analytical solution for an arbitrary polynomial normal pressure distribution applied to the crack faces is obtained and used as the basic solution in the method. The method is applied to several crack problems to study its efficiency and the results are compared to accurate stress-intensity factor solutions in the literature. The method gave reasonably accurate stress-intensity factors and crack opening displacements with minimal computing effort. Because the method must model only the uncracked body, finite-element models with many degrees of freedom are not warranted and therefore, the method has been implemented on personal computers

    An unusual bilateral variation of musculocutaneous nerve.

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    Musculocutaneous nerve arises from the lateral cord (C5,6,7) of brachial plexus. Communications between the branches of brachial plexus are not so common. During routine dissection, we observed bilateral variation in 60-year-old female cadaver. In the present case, median nerve represented as a musculocutaneous nerve which supplied biceps brachii and brachialis, further continued into forearm as lateral cutaneous nerve of forearm on the right arm. This branch did not pass through coracobrachialis muscle but the coracobrachialis was innervated by a branch from lateral cord of brachial plexus. We also observed an abnormal communicating branch between the musculocutaneous and median nerve on left side of the arm. These kinds of variations are important for surgeons while performing surgeries of axilla and upperlimb

    Experiencing space–time: the stretched lifeworlds of migrant workers in India

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    In the relatively rare instances when the spatialities of temporary migrant work, workers’ journeys, and labour-market negotiations have been the subject of scholarly attention, there has been little work that integrates time into the analysis. Building on a case study of low-paid and insecure migrant manual workers in the context of rapid economic growth in India, we examine both material and subjective dimensions of these workers’ spatiotemporal experiences. What does it mean to live life stretched out, multiplyattached to places across national space? What kinds of place attachments emerge for people temporarily sojourning in, rather than moving to, new places to reside and work? Our analysis of the spatiotemporalities of migrant workers’ experiences in India suggests that, over time, this group of workers use their own agency to seek to avoid the experience of humiliation and indignity in employment relations. Like David Harvey, we argue that money needs to be integrated into such analysis, along with space and time. The paper sheds light on processes of exclusion, inequality and diff erentiation, unequal power geometries, and social topographies that contrast with neoliberalist narratives of ‘Indian shining

    A study of methods of prediction and measurement of the transmission of sound through the walls of light aircraft

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    The acoustic intensity technique was applied to the sound transmission loss of panel structures (single, composite, and stiffened). A theoretical model of sound transmission through a cylindrical shell is presented

    Studies of new media radiation induced laser

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    Various lasants were investigated especially, 2-iodohepafluoropropane (i-C3F7I) for the direct solar pumped lasers. Optical pumping of iodine laser was achieved using a small flashlamp. Using i-C3F7I as a laser gain medium, threshold inversion density, small signal gain, and laser performance at the elevated temperature were measured. The experimental results and analysis are presented. The iodine laser kinetics of the C3F7I and IBr system were numerically simulated. The concept of a direct solar-pumped laser amplifier using (i-C3F7I) as the laser material was evaluated and several kinetic coefficients for i-C3F7I laser system were reexamined. The results are discussed

    Magnetic and Thermodynamic Properties of the Collective Paramagnet-Spin Liquid Pyrochlore Tb2Ti2O7

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    In a recent letter [Phys. Rev. Lett. {\bf 82}, 1012 (1999)] it was found that the Tb3+^{3+} magnetic moments in the Tb2_2Ti2_2O7_7 pyrochlore lattice of corner-sharing tetrahedra remain in a {\it collective paramagnetic} state down to 70mK. In this paper we present results from d.c. magnetic susceptibility, specific heat data, inelastic neutron scattering measurements, and crystal field calculations that strongly suggest that (1) the Tb3+^{3+} ions in Tb2_2Ti2_2O7_7 possess a moment of approximatively 5μB\mu_{\rm B}, and (2) the ground state g−g-tensor is extremely anisotropic below a temperature of O(100)O(10^0)K, with Ising-like Tb3+^{3+} magnetic moments confined to point along a local cubic diagonal(e.g.towardsthemiddleofthetetrahedron).Suchaverylargeeasy−axisIsinglikeanisotropyalonga diagonal (e.g. towards the middle of the tetrahedron). Such a very large easy-axis Ising like anisotropy along a direction dramatically reduces the frustration otherwise present in a Heisenberg pyrochlore antiferromagnet. The results presented herein underpin the conceptual difficulty in understanding the microscopic mechanism(s) responsible for Tb2_2Ti2_2O7_7 failing to develop long-range order at a temperature of the order of the paramagnetic Curie-Weiss temperature θCW≈−101\theta_{\rm CW} \approx -10^1K. We suggest that dipolar interactions and extra perturbative exchange coupling(s)beyond nearest-neighbors may be responsible for the lack of ordering of Tb2_2Ti2_2O7_7.Comment: 8 POSTSCRIPT figures included. Submitted to Physical Review B. Contact: [email protected]

    The Eastwood-Singer gauge in Einstein spaces

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    Electrodynamics in curved spacetime can be studied in the Eastwood--Singer gauge, which has the advantage of respecting the invariance under conformal rescalings of the Maxwell equations. Such a construction is here studied in Einstein spaces, for which the Ricci tensor is proportional to the metric. The classical field equations for the potential are then equivalent to first solving a scalar wave equation with cosmological constant, and then solving a vector wave equation where the inhomogeneous term is obtained from the gradient of the solution of the scalar wave equation. The Eastwood--Singer condition leads to a field equation on the potential which is preserved under gauge transformations provided that the scalar function therein obeys a fourth-order equation where the highest-order term is the wave operator composed with itself. The second-order scalar equation is here solved in de Sitter spacetime, and also the fourth-order equation in a particular case, and these solutions are found to admit an exponential decay at large time provided that square-integrability for positive time is required. Last, the vector wave equation in the Eastwood-Singer gauge is solved explicitly when the potential is taken to depend only on the time variable.Comment: 13 pages. Section 6, with new original calculations, has been added, and the presentation has been improve

    An Integrative Review of Web 3.0 in Academic Libraries

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    Purpose – The aim of this paper is to present an integrated literature review exploring the nature of responsive, semantic and interactive Web 3.0 technologies applicable for academic libraries. Design/methodology/approach – We conducted an integrated review of the literature combining a strategy of automated and keywords search. The main source for identifying the studies are Emerald Library Studies and Information & Knowledge Management eJournals, Web of Knowledge, and Library, Information Science & Technology Abstracts (EBSCO) databases. To this end, a sample of (n= 140) studies were analyzed to characterize the Web 3.0 trends and its applications based on theme, years and document types. Findings – A review of literature reveals that Web 3. needs evaluation as to what extent they are integrated, deployed and mainstreamed into library services and in information management practices. It is important to develop a conceptual framework that explores the linkages of Web 3.0 technologies and their applications in academic libraries. Originality/value –This review shows how Web 3.0 technologies enhance library services in its holistic conceptualization and how academic libraries are moving into a more robust, inclusive and adaptable phase in their service values and innovation

    Pilot scale studies on the beneficiation of complex sulphides by flotation column

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    Experiments using pilot size flotation Column as cleaner cell were conducted to evolve a suitable flow sheet for the production of bulk sulphide concentrates of Cu-Pb-Zn. The flotalion circuit consisting of roughing, scavenging, and two stage cleaning by conventional flotation machines was compared with the circuit where two stage cleaning operation was replaced with single stage cleaning by flotation column. It is clearly demonstrated that a single stage cleaning by flotation column is more efficient and sufficient to obtain bulk concentrate suitable for further processing. Of the two types of sparger systems used viz, TURBO and MICROCEL, the former was found to be better to achieve high quality concentrate
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