Oktay Çiçek and A. Cihat Baytaş
The purpose of this study is to numerically investigate the confined single-walled carbon nanotube-water nanofluid jet impingement heating of a cooled surface with a uniform heat…
Abstract
Purpose
The purpose of this study is to numerically investigate the confined single-walled carbon nanotube-water nanofluid jet impingement heating of a cooled surface with a uniform heat flux in the presence of a porous layer. The analysis of the convective heat transfer mechanism is introduced considering the buoyancy force effect under local thermal non-equilibrium conditions.
Design/methodology/approach
The governing equations for the nanofluid and solid phase are discretized by the finite volume method and the SIMPLE algorithm is used to solve these equations.
Findings
It is observed that there is an increase in a local variation of temperature along the upper wall with increasing Reynolds, Darcy and Grashof numbers. For given parameters, the optimum values of thermal conductivity ratio and porous layer thickness leading to better heating on the upper wall are found as Kr = 1.0 and S = 0.5, respectively. The maximum and minimum values of temperature on the upper wall are obtained in the case of higher nanoparticle volume fraction at Re = 100, however, the temperature values get higher along the upper wall with increasing nanoparticle volume fraction at Re = 300.
Originality/value
The effects of various parameters, such as Reynolds number, Darcy number and Grashof number, on thermal behavior and nanofluid flow are examined to determine the desirable heating conditions for the upper wall. This paper provides a solution to problems such as icing on the surface with a suitable thermal design and optimum geometric configuration.
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Gives a bibliographical review of the finite element methods (FEMs) applied for the linear and nonlinear, static and dynamic analyses of basic structural elements from the…
Abstract
Gives a bibliographical review of the finite element methods (FEMs) applied for the linear and nonlinear, static and dynamic analyses of basic structural elements from the theoretical as well as practical points of view. The range of applications of FEMs in this area is wide and cannot be presented in a single paper; therefore aims to give the reader an encyclopaedic view on the subject. The bibliography at the end of the paper contains 2,025 references to papers, conference proceedings and theses/dissertations dealing with the analysis of beams, columns, rods, bars, cables, discs, blades, shafts, membranes, plates and shells that were published in 1992‐1995.
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Xiaoyan Zeng, Pengcheng Shi and Wei Xie
This paper aims to reduce the confliction between different retail channels.
Abstract
Purpose
This paper aims to reduce the confliction between different retail channels.
Design/methodology/approach
By investigating a game-theoretic model consisting of a dominant hotel, a promoter and an OTA, the authors analyze the optimal amount of reserved rooms on the hotel's official website and realize the coordination between the hotel and the promoter with an appropriate contact.
Findings
When the gap between promoter’s reservation profits under different promotion cost coefficients is reasonable, complete coordination can be achieved in the supply chain. In addition, numerical examples are conducted to show that the profit of hotel and supply chain can be maximized with a moderate amount of reserved rooms on OTA.
Research limitations/implications
The authors only focus on one OTA scenarios, which overlooks the competition between OTAs.
Practical implications
Coordination strategy can fierce the increase on profit when the customer conversion rate increases.
Originality/value
The authors propose a contract menu to help the hotel avoid the profit loss under asymmetric promotion cost information.
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Hanxiong Zhang and Andrew Urquhart
Motivated by the debate on the patterns and sources of commodity futures returns, this paper investigates the performance of three investment trading strategies, namely, the…
Abstract
Purpose
Motivated by the debate on the patterns and sources of commodity futures returns, this paper investigates the performance of three investment trading strategies, namely, the momentum strategy of Jegadeesh and Titman (1993), the 52-week high momentum strategy of George and Hwang (2004) and the pairs trading strategy of Gatev et al. (2006) in the commodity futures market.
Design/methodology/approach
The three strategies are those given by Jegadeesh and Titman (1993), George and Hwang (2004) and Gatev et al. (2006), respectively.
Findings
The authors find that there is no significant reversal profit across 189 formation-holding windows for all the three strategies. However, there are statistical and economically significant momentum profits, and the profitability increases with the rising of formation-holding periods. Momentum returns are quite sensitive to market conditions but the crash of momentum returns is partly predictable. Return seasonality, risk and herding also provide partial explanation of the momentum profits.
Originality/value
The authors are the first to compare the performances of the pairs trading strategy of Gatev et al. (2006), the conventional momentum of Jegadeesh and Titman (1993), and the 52-week high momentum of George and Hwang (2004) under 189 formation-holding windows. Also, the authors are the first to investigate the association between herding behaviour and momentum returns in the commodity futures market.
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The purpose of this paper is to analyse inclusive growth that focuses on the creation of opportunities for all. Inclusive growth allows people to contribute to and benefit from…
Abstract
Purpose
The purpose of this paper is to analyse inclusive growth that focuses on the creation of opportunities for all. Inclusive growth allows people to contribute to and benefit from economic growth, while pro-poor growth approaches focusing on welfare of the poor only to reduce inequality.
Design/methodology/approach
Social capital forms with the development of human capital through schooling. Educated individuals are interested in dialogue and conversation. Interaction enables people to build trust, confidence and cooperation, to commit themselves to each other (i.e. reciprocity), and thereby to knit the social fabric. This study deals with the formation of social capital through development of human capital that is created through improvement of schooling and/or social inclusion. Creation of human and social capital is the basis for inclusive growth.
Findings
Recently, economics literature incorporates social capital for explaining regional disparities. Economic development of country depends on the impact of social capital which includes social culture, norms and regulations that promote economic reforms and development activities. Social capital forms with the development of human capital through schooling.
Research limitations/implications
More detail regional levels data are required for empirical findings.
Practical implications
This paper definitely suggests a clear policy for inclusive growth model in less developed regions/countries. Briefly and specific few policies are suggested as: first, improve productive consumption providing nutritional intake to all the excluded people of the society; second, dismal the social blocking and create the base for bridging social capital formation; third, improve school enrollment and strengthen the feeling of togetherness; fourth, design school curriculum as per need base; and fifth, develop institutions and improve capacity building.
Social implications
The Government expenditure policy should be focused more on productive consumption rather than unproductive consumption. The government should concentrate on the development of education and health sectors.
Originality/value
The inclusive economic growth process overcomes low-level equilibrium trap. The predictions of the model are examined empirically for a cross-section of countries and have substantial support in the chosen sample data.
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A.B.M. Zohrul Kabir and Ahmed S. Al‐Olayan
A new policy for joint optimization of age replacement and spareprovisioning has been proposed by incorporating a continuous review(s, S) type inventory policy, where s is the…
Abstract
A new policy for joint optimization of age replacement and spare provisioning has been proposed by incorporating a continuous review (s, S) type inventory policy, where s is the reorder level and S is the maximum stock level. Gives cost formulations for a single operating unit situation and outlines simulation procedure to determine optimal values of the decision variables by minimizing total cost of replacement and inventory. Studies the behaviour of this policy for a large number of case problems and highlights the effects of different cost elements, item failure characteristics and lead time characteristics. Also determines, for all case problems, optimal (s, S) policies to support Barlow‐Proschan age policy. Simulation results clearly indicate that the jointly optimal policy is more cost‐effective than Barlow‐Proschan policy.
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M. Kaltenbacher, S. Reitzinger, M. Schinnerl, J. Schöberl and H. Landes
The focus of this paper is on the efficient numerical computation of 3D electromagnetic field problems by using the finite element (FE) and multigrid (MG) methods. The magnetic…
Abstract
The focus of this paper is on the efficient numerical computation of 3D electromagnetic field problems by using the finite element (FE) and multigrid (MG) methods. The magnetic vector potential is used as the field variable and the discretization is performed by Lagrange (nodal) as well as Ne´de´lec (edge) finite elements. The resulting system of equations is solved by applying a preconditioned conjugate gradient (PCG) method with an adapted algebraic multigrid (AMG) as well as an appropriate geometric MG preconditioner.
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Canjun Yang, Hansong Wang, Qihang Zhu, Xiangzhi Liu, Wei Yang, Zhangyi Ma and Qianxiao Wei
Lower extremity exoskeletons have drawn much attention recently due to their potential ability to help the stroke and spinal cord injury patients to regain the ability of walking…
Abstract
Purpose
Lower extremity exoskeletons have drawn much attention recently due to their potential ability to help the stroke and spinal cord injury patients to regain the ability of walking. However, the balance of the human-exoskeleton system (HES) remains a big challenge. Usually, patients use crutches to keep balance when they wear exoskeleton. However, the balance depends greatly on the patient's balance ability and will be inevitably poor occasionally, which often causes the landing in advance of HES. The purpose of this paper is to propose a real-time stepping gait trajectory planning method based on the hip height variation of the swing leg to solve the problem.
Design/methodology/approach
The hip height of the swing leg was analyzed and measured. The simulation with MATLAB and the experimental test with the prototype of the proposed gait were conducted to verify its feasibility.
Findings
With the proposed method, HES can achieve successful step even when the balance kept by crutches is poor.
Research limitations/implications
Instead of actively avoiding the poor balance due to the instability caused by gravity, the method just modifies the stepping gait passively to avoid the landing in advance when the poor balance appears. In addition, it may not work well when the balance is too poor. Moreover, the proposed gait is just used in the initial stage of rehabilitation training. Besides, the step length of the gait must be limited for comfort.
Originality/value
A real-time stepping gait trajectory planning method based on the hip height variation of the swing leg is first proposed and its feasibility to avoid the landing in advance when the balance kept by the crutches is poor has been preliminary verified.
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Measures the intrinsic viscosities, in acetone and tetrahydrofurane (THF) at different temperatures, of a terpolymer of methyl methacrylate, ethyl acrylate and methacrylic acid…
Abstract
Measures the intrinsic viscosities, in acetone and tetrahydrofurane (THF) at different temperatures, of a terpolymer of methyl methacrylate, ethyl acrylate and methacrylic acid, prepared by semicontinuous emulsion polymerization (latex). Analyses data with the aid of the equations of Huggins, Kraemer, Martin, Schulz‐Blaschke and an equation recently suggested by Rao. Considers relationships between different parameters. By comparing uncleaned samples with samples purified by single precipitation or by dissolution and precipitation from THF, observes the effects of low‐molecular weight and water‐soluble on the intrinsic viscosities. Discusses solvent powers and effects of degree of purification and temperature on viscosity. Discusses polymer‐solvents interactions in terms of the acceptor/donor properties of the solvents. Concludes that purification of functionalized latices can lead to modifications of the original systems, through the elimination of different polymer chains.