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A connected thermomechanical boundary problem for an infinite TiNi cylinder, loaded by an external axial force and subjected to cooling from the surface, has been solved. The constitutive relations are given by the microstructural...
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A connected thermomechanical boundary problem for an infinite TiNi cylinder, loaded by an external axial force and subjected to cooling from the surface, has been solved. The constitutive relations are given by the microstructural model. Even for a low cooling rate, the temperature, stress, and martensite volume fraction are inhomogeneous, and the transformation-induced strain in the force direction decreases with an increase in the cylinder radius.
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This paper presents an experimental study on the added masses associated with the cylinders of different cross-sectional geometries (circular, square and rectangular of side ratio of 4) and angles of attack (theta = 0 degrees 90 d...
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This paper presents an experimental study on the added masses associated with the cylinders of different cross-sectional geometries (circular, square and rectangular of side ratio of 4) and angles of attack (theta = 0 degrees 90 degrees) with respect to incident flow. Two fluid media are considered, i.e. water and paraffin oil. The added mass is investigated from three different perspectives. Firstly, the added mass is estimated from a shift in the oscillation frequency of the cylinder in water or paraffin oil from that in still air, referred to as the average added mass. Thus defined added mass is dependent on both cylinder cross-sectional geometry and orientation but is independent of the fluid medium. The average added mass decreases from 1.52 at theta = 0 degrees to a minimum of 1.20 at theta = 45 degrees for the square cylinder but grows monotonically from 0.55 at theta = 0 degrees to 4.90 at theta = 90 degrees for the rectangular cylinder. Secondly, the added mass is calculated from the equation of structural dynamics. This added mass decreases linearly with the decreasing oscillation amplitude, thus called the amplitude-dependent added mass. Thirdly, the amplitude-dependent added mass is reduced to the unique added mass in the absence of vibration. The unique added mass is in general smaller (< 11.3% depending on geometry and theta) than the average added mass but displays a similar dependence on the cylinder cross-sectional geometry and theta. (C) 2020 Elsevier Ltd. All rights reserved.
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ASTM D 4832: Standard Test Method for Preparation and Testing of Controlled Low Strength Materila (CLSM) Test Cylinders currently permits three types of capping for CLSM cylinders: sulfur mortar (ASTM C 617), grpsum plaster (ASTM ...
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ASTM D 4832: Standard Test Method for Preparation and Testing of Controlled Low Strength Materila (CLSM) Test Cylinders currently permits three types of capping for CLSM cylinders: sulfur mortar (ASTM C 617), grpsum plaster (ASTM C 617), and unbonded neoprene restrained by rigid retainers (ASTM C 1231). These cappings were developed for portland cement concrete (PCC) cylindrs and all produce good estimates of PCC potentilawl strength.
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Natural convection has been extensively studied due to its presence in many engineering applications. It is one of the most important modes of heat transfer and arises due to buoyancy-induced flows resulting from temperature diffe...
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Natural convection has been extensively studied due to its presence in many engineering applications. It is one of the most important modes of heat transfer and arises due to buoyancy-induced flows resulting from temperature differences. This review presents a detailed summary of numerical and experimental studies related to laminar natural convection in enclosures with and without internal bodies. Square, circular, and elliptical cylinders are mostly considered as internal bodies. The presence of internal bodies makes significant changes in the flow characteristics within the enclosure. The effects on the flow regime and thermal fields of various parameters have been discussed in detail, including the Rayleigh number, aspect ratio, position of internal bodies, number of internal bodies, and inclination angle. The different flow regimes depending on the input parameters are categorized based on observations made from flow and thermal patterns. This review discusses various methodologies used by a large group of researchers to improve the hydrodynamic and thermal behavior for buoyancy-driven flows within an enclosure. (C) 2019 Elsevier Ltd. All rights reserved.
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Metal cylinders are being phased out in favour of composite LPG cylinders. These cylinders are light, have a pleasing colour and shape, are rust and corrosion resistant, UV resistant, and also 100% explosion proof. The aim of this...
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Metal cylinders are being phased out in favour of composite LPG cylinders. These cylinders are light, have a pleasing colour and shape, are rust and corrosion resistant, UV resistant, and also 100% explosion proof. The aim of this study is to understand consumer's awareness level and likeliness to shift to composite LPG cylinders. The paper studies the relative strength and weaknesses of composite LPG cylinders in comparison with traditional metal cylinders. This paper provides the opportunity to identify the consumer's needs and to bridge by suggesting technological applications, thus giving an idea to streamline the value chain of LPG cylinder distribution. This study also provides a holistic study of both B2B and B2C segments in the LPG cylinder value chain and thus provides a scope of improving the existing system. The paper will help the business leaders in composite LPG cylinder manufacturing along with cost saving opportunities to the distributors in the long run.
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Flow around an isolated generic sharp-edged object with varying height ratio (beta= 0-1) i.e. height from the rear end of the object to the front end (beta = H-2/H-1) has been investigated in cross-flow configuration covering stea...
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Flow around an isolated generic sharp-edged object with varying height ratio (beta= 0-1) i.e. height from the rear end of the object to the front end (beta = H-2/H-1) has been investigated in cross-flow configuration covering steady and periodic regimes at Reynolds number (Re) from 1 to 150 using air as a working fluid. Flow separation is delayed with a decrease in beta. Wake formed is the highest for beta = 1 (square object) and progressively decreases with the decrease in beta. The vortex shedding effect has been demonstrated on the heat transfer phenomena around the objects. For all the cases of height ratios, as Re increases the flow undergoes supercritical Hopf bifurcation to periodic state as steady-state condition loses its stability. Stuart-Landau theory has been used to determine the value of critical Re or the onset of vortex shedding for all the cases of height ratios. As beta increases from 0 to 0.7, the value of critical Re increases. Influence of surface vorticity and surface pressure on the overall drag coefficient (C-D) has been explored. Effect of beta on the Strouhal number (St) has been investigated and the findings are in agreement with previous results. Finally, correlations relating Lr, C-D, (Nu) over bar and St with Re and beta have been developed. (C) 2018 Elsevier Ltd. All rights reserved.
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Numerical investigations are presented for mixed convection problems in a concentric inner sinusoidal cylinder and an outer rotating circular cylinder, which were kept at constant hot and cold temperatures, respectively. The free ...
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Numerical investigations are presented for mixed convection problems in a concentric inner sinusoidal cylinder and an outer rotating circular cylinder, which were kept at constant hot and cold temperatures, respectively. The free space between the cylinders and the enclosure walls was filled with a water-Cu nanofluid. The governing equations are formulated for velocity, pressure, and temperature formulation and are modeled in COMSOL5.2a, a partial differential equation solver based on the Galerkin finite element method. The governing parameters considered are the solid volume fraction, [0, 0.02, 0.04, and 0.06], Re (1, 25, 100, 200, and 300), and Ra (less than 10~4), and the inner cylinder corrugation frequencies varied from (N = 3, 6, and 9). According to the calculations, the Reynolds number, the Rayleigh number, the nanoparticle volume fraction, and the number of corrugations play an important role of forming the stream and isothermal lines, the local and the average Nusselt number inside the annulus enclosure. The average Nusselt number decreases with increasing Reynolds number and the number of corrugations, while it increases as the Rayleigh number and the volume fraction increase.
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Given n points in Euclidean space E~d, we propose an algebraic algorithm to compute the best fitting (d - 1)-cylinder. This algorithm computes the unknown direction of the axis of the cylinder. The location of the axis and the rad...
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Given n points in Euclidean space E~d, we propose an algebraic algorithm to compute the best fitting (d - 1)-cylinder. This algorithm computes the unknown direction of the axis of the cylinder. The location of the axis and the radius of the cylinder are deduced analytically from this direction. Special attention is paid to the case d = 3 when n = 4 and n = 5. For the former, the minimal radius enclosing cylinder is computed algebrically from constrained minimization of a quartic form of the unknown direction of the axis. For the latter, an analytical condition of existence of the circumscribed cylinder is given, and the algorithm reduces to find the zeroes of an one unknown polynomial of degree at most 6. In both cases, the other parameters of the cylinder are deduced analytically. The minimal radius enclosing cylinder is computed analytically for the regular tetrahedron and for a trigonal bipyramids family with a symmetry axis of order 3.
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A solution for the equations governing dynamic thermopiezoelectric behavior is assumed in the form of an exponential e(i(kz+m0+wt)). The resulting formulation is reduced to one-dimension and will have both real and imaginary parts...
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A solution for the equations governing dynamic thermopiezoelectric behavior is assumed in the form of an exponential e(i(kz+m0+wt)). The resulting formulation is reduced to one-dimension and will have both real and imaginary parts. The Galerkin method and assumed shape functions are used to illustrate the formulation of the resulting eigenvalue problem. (c) 2005 Elsevier Ltd. All rights reserved.
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This paper investigates a peculiar case of thermal convection in a vertical porous prism with impermeable and partially conducting walls. We facilitate the analysis in the numerical finite-element environment alongside with analyt...
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This paper investigates a peculiar case of thermal convection in a vertical porous prism with impermeable and partially conducting walls. We facilitate the analysis in the numerical finite-element environment alongside with analytical considerations, in special cases where direct solutions are feasible. The present eigenvalue problem results in a non-normal-mode behaviour in the horizontal cross-sectional plane. Further, it is identified that the stagnation points for the horizontal flow are displaced from the extremal points of the temperature perturbation, for both symmetric and antisymmetric eigenfunctions. In addition, the corresponding normal-mode counterparts are provided from an analogy solution. We show that the critical Rayleigh number decreases with increasing Robin parameter values for all of the investigated aspect ratios. Finally, the influence of the aspect ratio on the critical Rayleigh number for the fully conducting wall case is identified. An asymptotic benchmark case of the Robin condition is validated from well-known analytical solutions which confirm the effectiveness of the predictions made in this paper. In fact, this is the first contribution that reports a three-dimensional geometry with a two-dimensional non-normal mode.
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