• Journal of Ocean Engineering and Technology
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• v.29 no.3
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• pp.255-262
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• 2015

The present study developed a numerical simulation tool for the coupled dynamic analysis of multiple turbines on a single floater (or Multiple Unit Floating Offshore Wind Turbine (MUFOWT)) in the time domain, considering the multiple-turbine aero-blade-tower dynamics and control, mooring dynamics, and platform motions. The numerical tool developed in this study was designed based on and extended from the single-turbine analysis tool FAST to make it suitable for multiple turbines. For the hydrodynamic loadings of floating platform and mooring-line dynamics, the CHARM3D program developed by the authors was incorporated. Thus, the coupled dynamic behavior of a floating base with multiple turbines and mooring lines can be simulated in the time domain. To investigate the effect of asymmetric aerodynamic loading on the global performance and mooring line tensions of the MUFOWT, one turbine failure case with a fully feathered blade pitch angle was simulated and checked. The aerodynamic interference between adjacent turbines, including the wake effect, was not considered in this study to more clearly demonstrate the influence of the asymmetric aerodynamic loading on the MUFOWT. The analysis shows that the unbalanced aerodynamic loading from one turbine in MUFOWT may induce appreciable changes in the performance of the floating platform and mooring system.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.28 no.11
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• pp.434-443
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• 2016

The evaporation of water from an aqueous solution is widely used in the food, desalination, pulp, and chemical industries. Usually, a large amount of energy is consumed in the evaporation process to boil off water due to atmospheric pressure. As a way of improving the energy efficiency of the evaporation process, the combination of multiple effect evaporation and thermal vapor recompression has been proposed and has become a successful technique. In this study, 4 multiple-effect falling film type evaporators for sugar solution are designed and the energy efficiency of the system is analyzed in response to the selection of the steam ejector position. Energy efficiency is increased and vapor is more compressed in the steam ejector as the Thermal Vapor Recompression (TVR) is arranged in the rear part of the evaporator system. A simplified 0-dimensional evaporator model is developed using non-linear equations derived from mass balances, energy balances, and heat transfer equations. Steam economy is calculated to compare the evaporation performance of the 4 proposed evaporators. The entrainment ratio, compression ratio, and expansion ratio are computed to check the ejector performance.

• Structural Engineering and Mechanics
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• v.53 no.3
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• pp.537-573
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• 2015

Multiple-step beams carrying intermediate lumped masses with/without rotary inertias are widely used in engineering applications, but in the literature for free vibration analysis of such structural systems; Bernoulli-Euler Beam Theory (BEBT) without axial force effect is used. The literature regarding the free vibration analysis of Bernoulli-Euler single-span beams carrying a number of spring-mass systems, Bernoulli-Euler multiple-step and multi-span beams carrying multiple spring-mass systems and multiple point masses are plenty, but that of Timoshenko multiple-step beams carrying intermediate lumped masses and/or rotary inertias with axial force effect is fewer. The purpose of this paper is to utilize Numerical Assembly Technique (NAT) and Differential Transform Method (DTM) to determine the exact natural frequencies and mode shapes of the axial-loaded Timoshenko multiple-step beam carrying a number of intermediate lumped masses and/or rotary inertias. The model allows analyzing the influence of the shear and axial force effects, intermediate lumped masses and rotary inertias on the free vibration analysis of the multiple-step beams by using Timoshenko Beam Theory (TBT). At first, the coefficient matrices for the intermediate lumped mass with rotary inertia, the step change in cross-section, left-end support and right-end support of the multiple-step Timoshenko beam are derived from the analytical solution. After the derivation of the coefficient matrices, NAT is used to establish the overall coefficient matrix for the whole vibrating system. Finally, equating the overall coefficient matrix to zero one determines the natural frequencies of the vibrating system and substituting the corresponding values of integration constants into the related eigenfunctions one determines the associated mode shapes. After the analytical solution, an efficient and easy mathematical technique called DTM is used to solve the differential equations of the motion. The calculated natural frequencies of Timoshenko multiple-step beam carrying intermediate lumped masses and/or rotary inertias for the different values of axial force are given in tables. The first five mode shapes are presented in graphs. The effects of axial force, intermediate lumped masses and rotary inertias on the free vibration analysis of Timoshenko multiple-step beam are investigated.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.40 no.1
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• pp.29-36
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• 2014

Dendrobium candidum is one of the well-known orchid on traditional and rare medicinal herb in China. We artificially cultured protocorm-like body and multiple shoots using the bioreactor culture system from Dendrobium candidum and experimented an efficacy as a cosmetic ingredient for skin care. Several studies previously have reported anti-tumor, wound healing and immunological function of Dendrobium candidum but other efficacies were not well known. In the present study, we investigated the cosmetic efficacy to know applicable value of protocorm-like body and multiple shoots cultured from Dendrobium candidum as a cosmetic ingredient. The biological activities of extracts from protocorm-like body, multiple shoots, aerial part and underground part of Dendrobium candidum were investigated. Results were found that extracts of protocorm-like body are superior to other extracts (underground part, aerial part and multiple shoots extracts) on anti-oxidant effect. Also, protocorm-like body extract contained the phenolic and flavonoid compounds more than aerial part, underground part and multiple shoots extracts. In addition, we investigated skin whitening effect related to whitening of skin. In tyrosinase activity and melanin synthesis assay, multiple shoots extract is superior to other extracts (aerial part, underground part and protocorm-like body), on inhibitory effect of tyrosinase activity and melanin synthesis respectively. These results indicate that the protocorm-like body and multiple shoots extracts cultured from Dendrobium candidum presents a new possibility of being applicable to skin improvement as a cosmetic ingredient.

• Journal of Korean Academy of Nursing
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• v.52 no.3
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• pp.324-340
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• 2022

Purpose: This study determined acculturative stress' effect on the life satisfaction of multicultural adolescents based on Roy's Adaptation Model and some earlier studies. Further, it examined the sequential multiple mediating effects of bicultural acceptance attitude, self-esteem, and social withdrawal on life satisfaction. Methods: Participants included 1,163 multicultural adolescents who participated in the sixth Multicultural Adolescents Panel Study. A hypothesis test was conducted using Hayes' Process Macro Model 81. Results: Life satisfaction increased with a decline in acculturative stress. Each of bicultural acceptance attitude, self-esteem, and social withdrawal had a single mediating effect on the relationship between acculturative stress and life satisfaction in multicultural adolescents. The sequential multiple mediating effects of bicultural acceptance attitude and self-esteem were confirmed significant after their impact on the relationship between acculturative stress and life satisfaction was analyzed. Bicultural acceptance attitude and social withdrawal were found to have a significant sequential multiple mediating effect on the relationship, as well. Conclusion: This study's results demonstrate that acculturative stress reduction is critical to improving multicultural adolescents' life satisfaction. Bicultural acceptance attitude, self-esteem, and social withdrawal have a single mediating or sequential multiple mediating effect on the relationship between multicultural adolescents' acculturative stress and life satisfaction. The findings, which highlight mediating effects, indicate that by increasing bicultural acceptance attitude and self-esteem, and reducing social withdrawal, multicultural adolescents' life satisfaction can be improved.

• Journal of Gifted/Talented Education
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• v.19 no.1
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• pp.69-94
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• 2009

The purpose of this study was to develop and apply a Korean language education program based on multiple intelligences in a bid to foster the multiple intelligences, self-efficacy and achievement motivation of elementary schoolers in regular language arts class. It's basically meant to create the educational conditions for every child to exert his or her abilities. Two research questions were posed: 1. What should be the objectives, content and teaching-learning methods of a Korean language education program based on multiple intelligences? 2. What effect does a Korean education program based on multiple intelligences have on children's multiple intelligences, self-efficacy and achievement motivation? The subjects in this study were 58 Students in two different third-grade classes in M elementary school in the city of Daejeon. A Korean language education program based on multiple intelligences was implemented during a 4month period of time, and an inclusive approach of multiple intelligences and cooperative learning were applied. The major findings of the study were as follows: First, in order to develop a Korean education program based on multiple intelligences, the kinds of themes that could cover multiple intelligences in an inclusive way were selected in consideration of the learning objectives of the major units of a third-grade language arts textbook(second semester) of the 7th national elementary language arts curriculum. And then an inclusive Korean education program was prepared, which consisted of four stages: problem awareness, problem-solving planning, problem solving, and reflection/application/development. Second, the Korean education program based on multiple intelligences had a positive effect on the children's multiple intelligences, self-efficacy and achievement motivation and suggested some of new directions for school education that typically stressed linguistic and logical-mathematical intelligences only.

• Korean Journal of Culture and Social Issue
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• v.25 no.1
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• pp.55-77
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• 2019

Negative experience related to work-family multiple roles has been associated with internalizing problems in mothers. In particular, employed mothers with preschool children report high degree of stress. As such, the need to examine potential factors that may explain and alleviate such difficulties has been emphasized. The purpose of this study was thus to examine the mediating effect of sociotropy on the relationship between negative work-family multiple roles and internalizing problems in employed mothers with preschool children. The Negative Experience of Work-Family Multiple Roles Scale, Adult Self Report (ASR) Scale, and Personal Style Inventory-II (PSI-II), were completed by 208 employed mothers with preschool children through an online survey. The results indicated that the direct effect of negative experience of work-family multiple roles on internalizing problems was statistically significant and the indirect effect of sociotropy in this relationship was significant. These findings suggest that sociotropy in employed mothers may indirectly explain internalizing problems related to multiple roles. The implications of sociotropy in negative experience of work-family multiple roles and internalizing problems are discussed.

• Korean Chemical Engineering Research
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• v.60 no.1
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• pp.25-33
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• 2022

This study developed the black liquor evaporation process models using the multiple-effect-evaporator according to the number of effects to predict steam consumption. The developed models were divided into the black liquor preheating and evaporation processes, and a virtual reboiler was added to predict steam consumption. In simulation results, the steam consumption in the double-effect-evaporator was decreased by 48.9 %, and as the number of effects increased, the steam consumption was decreased. Finally, the steam consumption in the octuple-effect-evaporator was decreased by 61.2 %. Also, this study suggests a strategy for deriving the optimal number of effects in the process by analyzing the latent heat recovered from the saturated vapor produced in the multiple-effect-evaporator and the amount of saturated vapor produced by each effect.

• Journal of Power Electronics
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• v.19 no.5
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• pp.1122-1132
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• 2019

In this paper, aiming at high-voltage applications, transformer windings schemes of multiple-output two-transistor flyback converters are investigated, which are mainly based on the stray capacitances effect. First, based on a transformer model including equivalent stray capacitors, the operational principle of the converter is presented, and the main influence of its stay capacitors is determined. Second, the windings structures of the transformer are analyzed and designed based on the stray capacitances effect. Third, the windings arrangements of the transformer are analyzed and designed through a coupling analysis of the secondary windings and a stray capacitance analysis between the primary and secondary windings. Finally, the analysis and design conclusions are verified by experimental results obtained from a 60W laboratory prototype of a multiple-output two-transistor flyback converter.

• Journal of Distribution Science
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• v.13 no.10
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• pp.15-21
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• 2015

Purpose - This study examines a bundling effect on production and distribution in a patent-protected industry. Despite the heavy use of bundling strategies in the information and technology industry, literature has paid scant attention to bundling of intellectual property rights. This study examines a theoretical exploration of the bundling effect on licensing behavior. Research design, data, and methodology - To address this behavior, we build a simplified model consisting of three stages: 1) bundling decision, 2) licensing agreement, and 3) competition. The subgame perfect Nash equilibrium is applied to the model. Results - A single-patent holder with superior technology grants its own license to the multiple-patent firm, thereby leaving the market. Anticipating the single right holder's licensing strategy, the multiple-patent firm offers a bundle, making the single-right holder's bargaining position weaker. Conclusions - Bundling is an effective business strategy, resulting in multiple products for a firm as it faces other firms with single-product lines in each market. Taking advantage of the multi-patent or multi-product lines, the firm utilizes the bundling strategy obtaining better technology from the standalone single-patent firms.