Yasuhito Takahashi, Koji Fujiwara, Takeshi Iwashita and Hiroshi Nakashima
This paper aims to propose a parallel-in-space-time finite-element method (FEM) for transient motor starting analyses. Although the domain decomposition method (DDM) is suitable…
Abstract
Purpose
This paper aims to propose a parallel-in-space-time finite-element method (FEM) for transient motor starting analyses. Although the domain decomposition method (DDM) is suitable for solving large-scale problems and the parallel-in-time (PinT) integration method such as Parareal and time domain parallel FEM (TDPFEM) is effective for problems with a large number of time steps, their parallel performances get saturated as the number of processes increases. To overcome the difficulty, the hybrid approach in which both the DDM and PinT integration methods are used is investigated in a highly parallel computing environment.
Design/methodology/approach
First, the parallel performances of the DDM, Parareal and TDPFEM were compared because the scalability of these methods in highly parallel computation has not been deeply discussed. Then, the combination of the DDM and Parareal was investigated as a parallel-in-space-time FEM. The effectiveness of the developed method was demonstrated in transient starting analyses of induction motors.
Findings
The combination of Parareal with the DDM can improve the parallel performance in the case where the parallel performance of the DDM, TDPFEM or Parareal is saturated in highly parallel computation. In the case where the number of unknowns is large and the number of available processes is limited, the use of DDM is the most effective from the standpoint of computational cost.
Originality/value
This paper newly develops the parallel-in-space-time FEM and demonstrates its effectiveness in nonlinear magnetoquasistatic field analyses of electric machines. This finding is significantly important because a new direction of parallel computing techniques and great potential for its further development are clarified.
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Kenichi Nakashima and Arvinder P.S. Loomba
The purpose of this study is to consider the acquisition of end‐of‐life products under variable quality consideration for remanufacturing so as to determine optimal control policy…
Abstract
Purpose
The purpose of this study is to consider the acquisition of end‐of‐life products under variable quality consideration for remanufacturing so as to determine optimal control policy that minimizes per‐period expected costs that may guide future consideration by practitioners.
Design/methodology/approach
The authors review recent literature on reverse supply chains and remanufacturing. They utilize an undiscounted Markov decision process methodology to ascertain the order amount of remanufacturable products using optimal control under minimum cost criterion.
Findings
The authors conclude that it makes sense for firms to focus on the cost management with production control based on quality levels with different acquisition costs of remanufacturable products.
Research limitations/implications
Although the Markov decision process methodology – which is well supported in literature – was diligently followed, the nature of analysis and discussion may be subject to authors’ bias. Future investigation and adoption of the methodological approach used will verify the paper findings.
Practical implications
This study determines optimal control policy for ordering specific amount of product that minimizes per‐period expected costs for remanufacturing. Reverse supply‐chain professionals now have an easy‐to‐follow guide when acquiring end‐of‐life remanufacturable products alternatives with variable quality.
Social implications
This study determines the optimal policy for ordering remanufacturable products. This information enables practitioners to reduce their carbon footprint in reverse supply chain through inspection/sorting before remanufacturing by processing only the type, quality, and quantity of needed product.
Originality/value
For reverse supply chain to be taken seriously by senior management in firms, it is imperative that practitioners in this field synchronize their operational‐level ordering decisions with holistic cost minimization objective (to maximize value recovery) to stay viable.
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Mingjing Jiang, Fang Liu, Huaning Wang and Xinxin Wang
The purpose of this paper is to present an investigation of the effect of different gravity conditions on the penetration mechanism using the two-dimensional Distinct Element…
Abstract
Purpose
The purpose of this paper is to present an investigation of the effect of different gravity conditions on the penetration mechanism using the two-dimensional Distinct Element Method (DEM), which ranges from high gravity used in centrifuge model tests to low gravity incurred by serial parabolic flight, with the aim of efficiently analyzing cone penetration tests on the lunar surface.
Design/methodology/approach
Seven penetration tests were numerically simulated on loose granular ground under different gravity conditions, i.e. one-sixth, one-half, one, five, ten, 15 and 20 terrestrial gravities. The effect of gravity on the mechanisms is examined with aspect to the tip resistance, deformation pattern, displacement paths, stress fields, stress paths, strain and rotation paths, and velocity fields during the penetration process.
Findings
First, under both low and high gravities, the penetration leads to high gradients of the value and direction of stresses in addition to high gradients in the velocity field near the penetrometer. In addition, the soil near the penetrometer undergoes large rotations of the principal stresses. Second, high gravity leads to a larger rotation of principal stresses and more downward particle motions than low gravity. Third, the tip resistance increases with penetration depth and gravity. Both the maximum (steady) normalized cone tip resistance and the maximum normalized mean (deviatoric) stress can be uniquely expressed by a linear equation in terms of the reciprocal of gravity.
Originality/value
This study investigates the effect of different gravity conditions on penetration mechanisms by using DEM.
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Naoki Kamimaeda, Noriaki Izumi and Kôiti Hasida
The purpose of this paper is to evaluate participants' contributions to the development of discussion and knowledge creation as organizational knowledge management, and thereby…
Abstract
Purpose
The purpose of this paper is to evaluate participants' contributions to the development of discussion and knowledge creation as organizational knowledge management, and thereby help them better develop the discussion.
Design/methodology/approach
To evaluate participants' contributions more accurately, a method which analyzes discussion structures by Discourse Semantic Authoring was employed, which represents discussion structures explicitly in terms of discourse and dialogue relations.
Findings
The method successfully evaluates participants based on the content of their comments rather than their number. More fine‐grain semantic structure should be considered in order to improve the accuracy of this evaluation.
Originality/value
This paper presents a first attempt to analyze discussion structures to evaluate participants' contributions.
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Marjan Svetličič, Matija Rojec and Andreja Trtnik
A survey of selected theories relevant to foreign direct investment abroad is the basis for predicting when outward FDI from more developed Central European Countries begins…
Abstract
A survey of selected theories relevant to foreign direct investment abroad is the basis for predicting when outward FDI from more developed Central European Countries begins. Slovenian experiences are used as case studies. Although inward FDI is still dominant, outward FDI is picking up in terms of sales operations in developed countries, but also as manufacturing units in other Central European countries. It is argued that outward investment can promote the restructuring of traditional industries. Outward FDI is starting today at an earlier stage of development, not only as a result of the accumulation of firm-specific advantages, but also from a position of weakness in order to learn from abroad and to strengthen competitive advantages. Outward FDI enhances the process of restructuring where such internationalisation is synchronised with the loss of comparative advantages of home countries. The case of Slovenia is evaluated in terms of geographical allocation of such investments, sectoral distribution and dynamic changes.
Madelon Willemsen, Julien Pollack and Chivonne Algeo
There are significant, ongoing threats of species extinction. Threatened species recovery programs are an important way of reducing this threat, but many recovery programs are…
Abstract
Purpose
There are significant, ongoing threats of species extinction. Threatened species recovery programs are an important way of reducing this threat, but many recovery programs are unsuccessful. The purpose of this paper is to explore the issues facing species recovery programs, and the potential benefits to be found in managing threatened species recovery from a project management perspective.
Design/methodology/approach
This research used the Grounded Theory Method to analyze the contents of four senate inquiries and 21 interviews with recovery experts. The Grounded Theory Method was then used to inductively develop concepts and theories that explain some of the issues faced in the delivery of recovery programs in Australia. These were explored from a project management perspective, to understand ways that project management could provide benefit to the recovery planning process.
Findings
Eight core challenges that have an impact on recovery emerged from the data. It was identified that there is a general lack of integration of project management into the recovery process. This was found to be particularly evident in terms of the recovery project lifecycle, risk management and stakeholder management. Strategies for addressing these issues are discussed.
Originality/value
Conservation scientists typically focus on technical recovery competencies. The authors argue that managing recovery from a project management perspective will increase recovery success rates through an increased focus on the contextual and behavioral competencies that are essential to the management and delivery of recovery projects and programs.
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The sustainable performance of hotels which constitute a major part of the tourism industry, gains increasing importance day by day. Sustainability has become mandatory not only…
Abstract
The sustainable performance of hotels which constitute a major part of the tourism industry, gains increasing importance day by day. Sustainability has become mandatory not only for the tourism industry but also for all industries producing goods and services. Reducing the negative impact of development on the environment and environmental innovation which aims to benefit from natural resources and energy effectively and consciously helps hotels to be sustainable. The tourism industry has a complex structure and exists as being intertwined with other branches of science. Tourism, which is a multidisciplinary industry, is nourished by other branches of science as well as supplies other fields of science by providing working space. Some new solutions that are put forward by materials science and engineering take place in the tourism industry as new innovations. Owing to this interaction, the workload of the personnel working in hotels is reduced and the enterprises save material and energy. At the same time, the customers who benefit from the services of the hotels consume the services in more comfortable and safer environments.
Ceramic materials are generally used in toilet and bathroom parts of hotels. However, ceramics are observed to be used in lobbies, cafes, restaurants, pools, facades, and similar areas in addition to toilets and baths in hotels. The aim of this study is to identify new ceramic solutions that affect and contribute to the sustainability of the hotels which is a major sector under the roof of the tourism industry and to contribute the literature. In order to actualize this aim, the document analysis method which is one of qualitative research methods was used and the literature search was carried out to identify new ceramic solutions. The result of study includes moisture control tiles with the ability to keep the humidity at normal standards in terms of human health and that can be used in hotels, facade systems that clean themselves and the polluted air, thermal coating systems for heat insulation, antibacterial materials that provide hygiene, and dirt repelling products. Also, it is seen that there are new ceramic solutions such as costless night lighting and security strips as well as materials with a phosphorescence property for aesthetical purposes and also, tiles with heat control which offer different possibilities aesthetically. It is observed that the different benefits obtained from each of identified new ceramic solutions ease off the workload of personnel working in the hotels, enable material and energy saving in hotels and at the same time, provide an accommodation in a more comfortable and safer environment for customers. In addition to this, the use of high-technology ceramics and nanomaterials in the field of tourism creates places where technology and aesthetics combine.
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Maria da Graça Carvalho and Pedro Jorge Coelho
A fully three‐dimensional model has been applied to an oil‐fired water tube boiler in order to predict the flow, temperature, mixture fraction, species concentrations and the heat…
Abstract
A fully three‐dimensional model has been applied to an oil‐fired water tube boiler in order to predict the flow, temperature, mixture fraction, species concentrations and the heat flux distributions to the furnace walls. The partial differential equations governing conservation of mass, momentum and energy as well as those describing the combustion phenomena are discretized by a finite volume method and solved numerically. Radiative heat transfer is handled by the discrete transfer method. Predicted results are presented and compared with experimental data for the heat fluxes. The results have suggested that 3‐D models of the present kind can be used with some confidence for design calculations.