• Journal of Ocean Engineering and Technology
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• v.8 no.1
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• pp.105-113
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• 1994

Double-diffusive convection induced by simultaneously-imposed lateral temperature and concentration gradients in a rectangular enclosure with aspect retio, 2.0 has been studied experimentally for adiabatic and isothermal horizontal boundary conditions. Visual observations show two distinct flow structures depending on the buoyancy ratio. The unicell flow structure is observed for a lower buoyancy ratio while the layered flow structure appears for a higher buoyancy ratio. There exists an unstable flow regime between two buoyancy ratios.

• Journal of the Korean Society for Industrial and Applied Mathematics
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• v.24 no.1
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• pp.103-119
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• 2020

In this work, the hydromagnetic and thermal characteristics of natural convection flow in a vertical parallel plate micro-porous-channel with suction/injection is analytically studied in the presence of Hall current by taking the temperature jump and the velocity slip at the wall into account. The governing equations, exhibiting the physics of the flow formation are displayed and the exact analytical solutions have been obtained for momentum and energy equations under relevant boundary conditions. The impact of distinct admissible parameters such as Hartmann number, Hall current parameter, permeability parameter, suction/injection parameter, fluid wall interaction parameter, Knudsen number and wall-ambient temperature ratio on the flow formation is discussed with the aid of line graphs. In particular, as rarefaction parameter on the micro-porous-channel surfaces increases, the fluid velocity increases and the volume flow rate decreases for injection/suction.

• Structural Engineering and Mechanics
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• v.54 no.4
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• pp.755-769
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• 2015

In this study, a 2-D finite element formulation in the frame of nonlocal integral elasticity is presented. Subsequently, the bending problem of a nanobeam under different types of loadings and boundary conditions is solved based on classical beam theory and also 3-D elasticity theory using nonlocal finite elements (NL-FEM). The obtained results are compared with the analytical and numerical results of nonlocal differential elasticity. It is concluded that the classical beam theory and the nonlocal differential elasticity can separately lead to significant errors for the problem under consideration as distinct from 3-D elasticity and nonlocal integral elasticity respectively.

• Steel and Composite Structures
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• v.33 no.2
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• pp.245-259
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• 2019

The present study aims to investigate the ultimate strength and geometric nonlinear behavior of composite plates containing initial imperfection subjected to combined end-shortening strain and lateral pressure loading by using a semi-analytical method. In this study, the first order shear deformation plate theory is considered with the assumption of large deflections. Regarding in-plane boundary conditions, two adjacent edges of the laminates are completely held while the two others can move straightly. The formulations are based on the concept of the principle of minimum potential energy and Newton-Raphson technique is employed to solve the nonlinear set of algebraic equations. In addition, Hashin failure criteria are selected to predict the failures. Further, two distinct models are assumed to reduce the mechanical properties of the failure location, complete ply degradation model, and ply region degradation model. Degrading the material properties is assumed to be instantaneous. Finally, laminates having a wide range of thicknesses and initial geometric imperfections with different intensities of pressure load are analyzed and discuss how the ultimate strength of the plates changes.

• Structural Engineering and Mechanics
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• v.89 no.3
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• pp.323-334
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• 2024

Physical and chemical factors can cause traditional timber constructions to lose structural integrity. Knowing the dynamic properties of the building components is vital to avoid damage to the buildings from dynamic effects, a subset of physical effects. In this work, spruce and scotch pine wooden beams that had been strengthened in three distinct ways with carbon fiber strengthened polymer (CFRP) were investigated for changes in their dynamic properties. For this, CFRP was used to strengthening unstrengthened wooden beams in the form of bottom confinement, U-shaped confinement, and full confinement after the dynamic parameters of the beams were determined. By using experimental modal analysis with both free-free and fixed-fixed boundary conditions, the beams'initial natural frequencies were identified.

• Advances in nano research
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• v.17 no.4
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• pp.293-299
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• 2024

In this paper, the simplified ordinary differential equations are solved with shooting technique. The concentration and microorganism slip boundary conditions are implemented. Non-linear expression is reduced via non-dimensional variables. The microorganism distribution declines by increasing Lewis number and microorganism slip parameter. Behavior of distinct influential parameters viz: Eckert number, bioconvected Lewis number, bioconvected Peclet number, microorganisms slip parameter are investigated graphically and analyzed for concentration and microorganism. Enhanced concentration is correlated with energy activation. An acceptable agreement is reached when the numerical technique is compared to the existing literature. The magnitude of microorganism transfer rate shows decreasing behavior for higher values of slip parameters.

• International Journal of Air-Conditioning and Refrigeration
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• v.12 no.1
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• pp.50-60
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• 2004

An experimental analysis using three-dimensional Laser Doppler Velocimetry(LDV) measurement and computational analysis using the Reynolds stress model in FLUENT are conducted to give a clear understanding of the effect of blade loading on the structure of tip leakage flow in a forward-swept axial-flow fan operating at the maximum efficiency condition ($\Phi$=0.25) and two off-design conditions ($\Phi$=0.21 and 0.30). As the blade loading increases, the onset position of the rolling-up of tip leakage flow moves upstream and the trajectory of tip leakage vortex center is more inclined toward the circumferential direction. Because the casing boundary layer becomes thicker and the mixing between the through-flow and the leakage jet with the different flow direction is enforced, the streamwise vorticity decays more fast with the blade loading increasing. A distinct tip leakage vortex is observed downstream of the blade trailing edge at $\Phi$=0.30, but it is not observed at $\Phi$=0.21 and 0.25.

• Steel and Composite Structures
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• v.31 no.1
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• pp.27-41
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• 2019

Shear lag effect can be an important phenomenon to consider in design of the steel-concrete composite beams. Researchers have found that the effect can be strongly related with the moment distribution, the stiffness and the ductility of the composite beams. For continuous composite beams expected to sustain hogging moment, the shear lag effect can be more distinct as cracking of the concrete slab reduces its shear stiffness. Despite its influences on behaviour of the steel-concrete composite beams, a method for calculating the shear lag effect in steel-concrete composite beams sustaining hogging moment is still not available. Shear lag effect in steel-concrete composite beams sustaining hogging moment is investigated in this paper. A method was proposed specifically for predicting the effect in the cracked part of the steel-concrete composite beam. The method is validated against available experimental data. At last, FE studies are conducted for steel-concrete composite beams with different design parameters, loading conditions and boundary conditions to further investigate the shear lag effect and compare with the proposed method.

• Journal of Distribution Research
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• v.16 no.3
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• pp.77-104
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• 2011

As business marketers placed greater emphasis on building long-term relationships, trust has assumed a central role in the development of marketing theory(Dwyer, Schurr, and Oh 1987; Mogan and Hung 1994) and practice(Dertouzos, Lester, and Solow 1989). Marketing research on trust primarily focuses on two targets of trust: supplier firms and their salesperson. Trust of firm and trust of salesperson, though related, represent different concepts(Doney and Cannon 1997). Also, the definition of trust proposed by Ganesan(1994) reflects two distinct components: (1) credibility, which is based on the extent to which the buyer believes that the seller has the required expertise to perform the job effectively and reliably and (2) benevolence, which is based on the extent to which the buyer believes that the seller has intentions and motives beneficial to the buyer when new conditions arise, conditions for which a commitment was not made. The existing marketing research focuses on how trust of a firm and its salesperson has a differential effects on loyalty. However, these extant research pays little attention to the moderating effects that explicitly examine how two trust dimensions of salesperson(credibility and benevolence) affects loyalty of firm. The purpose of this study is to provide new insight into boundary conditions(individualism and industry type) that credibility and benevolence influences loyalty.

• Tribology and Lubricants
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• v.40 no.6
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• pp.181-188
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• 2024

In additive manufacturing, understanding the mechanical properties of metal powders is essential to optimize manufacturing processes. This study examines the tensile and compressive characteristics of mono- and polycrystalline copper structures using molecular dynamics simulations. Specifically, we investigate how localized thermal fusion affects the mechanical performance of these copper samples at various energy flux levels and loading conditions. We model hemispherical copper particles to mimic localized sintering effects, with variations in energy absorption resulting in structural transformations, including the face-centered cubic (FCC) to hexagonal close-packed (HCP) phase transition. The first observations indicates that energy absorption enhances the transition from FCC to HCP, initiating at the necking region and propagating at a 45° angle relative to the elongation axis. Additionally, compared to single-crystal structures, polycrystalline structures exhibit more pronounced phase transitions under tensile deformation. Additionally, polycrystalline structures exhibit more pronounced phase transitions under tensile deformation compared to single-crystal structures. Another observations highlight distinct trends in grain boundary generation and growth: single-grain copper samples show grain boundary growth originating from the free surface, while polycrystalline copper samples exhibit newly formed grain boundaries emerging from their initial structures. To quantify the differences between tensile and compressive tests, normalized normal pressure and von Mises stress are evaluated under varying levels of localized energy flux during thermal bonding. This study supports the design and optimization of copper-based additive manufacturing processes by providing useful insights into the microscopic mechanics that govern phase transformations in copper during sintering.