• Journal of the Korean Solar Energy Society
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• v.23 no.3
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• pp.37-44
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• 2003

This paper presents the modeling and analysis of V47-660 kW wind turbine generation system(WTGS) in Jeju wind farm using Psim program. Generally, WTGS is composed of complicated machinery. So it is very difficult to present the mathematic model. This means that WTGS has a nonlinear system. Using the real output data from V47 WTGS for one year, it is simply possible to express the rotor and gear coupling system as a torque generator according to wind speed. Also, the modeling of electrical system can be able to present using the data sheet from the company. To analyze the proposed method, results of computer simulation using Psim program are presented to support the discussion.

• Journal of Korea Water Resources Association
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• v.44 no.6
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• pp.461-470
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• 2011

Abrupt and gradual levee breach analyses on the flat domain were implemented by laboratory experiments and numerical simulations. To avoid the reflective wave from the side wall the experiment was performed in a large domain surrounded by waterway. A numerical model was developed for solving the two-dimensional gradual levee breach flow. The results of the numerical simulation developed in this study showed good agreement with those of the experimental data. However, even if the numerical schemes effectively replicated the trends of the observed water depth for the first shock, there were little differences for the second shock. In addition, even though the model considered the Smagorinsky horizontal eddy viscosity, the location and height of the hydraulic jump in the numerical simulation were not fairly well agree with experimental measurements. This shows the shallow water equation solver has a limitation which does not exactly reproduce the energy dissipation from the hydraulic jump. Further study might be required, considering the energy dissipation due to the hydraulic jump or transition flow from reflective wave.

• Journal of the Korea Institute of Building Construction
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• v.2 no.4
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• pp.177-182
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• 2002

The purpose of this study is to develope the strength prediction model by Maturity Method. A maturity function is a mathematical expression to account for the combined effects of time and temperature on the strength development of a cementious mixture. The method of equivalent ages is to use Arrhenius equation which indicates the influence of curing temperature on the initial hydration ratio of cement. For the experimental factors of this study, we selected the concrete mixing of W/C ratio 45, 50, 55 and 60% and curing temperature 5, 10, 20 and $30^{\circ}C$. And we compare and evaluate with logistic model that is existing strength prediction model, because we have to verify adaption possibility of new strength prediction model which is proposed by maturity method. As the results, it is found that investigation of the activation energy that are used to calculate equivalent age is necessary, and new strength prediction model was proved to be more accurate in the strength prediction than logistic model in the early age. Moreover, the use of new model was more reasonable because it has low SSE and high decisive factor.

• Nuclear Engineering and Technology
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• v.39 no.4
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• pp.287-298
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• 2007

As part of the $AP1000^{TM}$ pressurized water reactor design certification program, a series of integral systems tests of the nuclear steam supply system was performed at the APEX-1000 test facility at Oregon State University. These tests provided data necessary to validate Westinghouse safety analysis computer codes for AP1000 applications. In addition, the tests provided the opportunity to investigate the thermal-hydraulic phenomena expected to be important in AP1000 small-break loss of coolant accidents (SBLOCAs). The APEX-1000 facility is a 1/4-scale pressure and 1/4-scale height simulation of the AP1000 nuclear steam supply system and passive safety features. A series of eleven tests was performed in the APEX-1000 facility as part of a U.S. Department of Energy contract. In all, four SBLOCA tests representing a spectrum of break sizes and locations were simulated along with tests to study specific phenomena of interest. The focus of this paper is the SBLOCA tests. The key thermal-hydraulic phenomena simulated in the APEX-1000 tests, and the performance and interactions of the passive safety-related systems that can be investigated through the APEX-1000 facility, are emphasized. The APEX-1000 tests demonstrate that the AP1000 passive safety-related systems successfully combine to provide a continuous removal of core decay heat and the reactor core remains covered with considerable margin for all small-break LOCA events.

• Korean Chemical Engineering Research
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• v.56 no.6
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• pp.804-810
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• 2018

Most biofuel companies are in a small scale with short experience of operating the entire supply chain. In order to compete with existing fossil fuel competitors, renewable companies should be more responsive to demand. It is financially important to reflect this in the decision supporting system of the company. This paper addresses an evolutionary algorithm based methodology for the distribution problem of renewable energies. A numerical example was presented to illustrate the applicability of the proposed methodology with some remarks.

• Journal of Drive and Control
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• v.15 no.4
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• pp.39-47
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• 2018

Recently, as environmental regulations for earth-moving equipment have been tightening, advanced systems such as electronic control, have been introduced for energy savings. An IMV (Independent Metering Valve) consisting of four 2-way valves, is an electro-hydraulic control systems that provides more flexible controllability, and potential for energy savings in excavators, when compared to the conventional 4-way spool valve system. To fully maximize use of an IMV, the bi-directional flow control valve that can regulate a large amount of flow in both directions, should be adopted. The hydraulic circuit of an IMV applied to an excavator from an overseas construction equipment company, reveals the flow control valve with the compound of proportional solenoid valve for first stage, and 2-way spool valve for the second stage. Moreover, the two spools are interconnected by a feedback spring, presumed to compensate for flow force acting on the second stage spool. This paper addresses the static analysis of flow control valve in an IMV to investigate the improvement of robustness, against flow force by the feedback spring. From the steady-state analysis of flow control valve model, it can be concluded that the feedback spring facilitates maintaining linearity of spool displacement for control input, and relatively constant flow for load disturbance.

• Nuclear Engineering and Technology
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• v.53 no.5
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• pp.1705-1716
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• 2021

Bangladesh, as a newcomer country, is expecting to start her nuclear power journey by 2022. Due to evident reasons, newcomer nuclear countries face several key challenges concerning the development of national nuclear safety infrastructure. The paper investigates the status of the 7 key safety infrastructure issues out of the 19 and readiness of the supportive organizations, laboratories, and workforces following the International Atomic energy Agency's status evaluation guide at milestone 3 and foreign countries' practice. Much progress has been achieved at phase 3 regarding the establishments of a few Acts, a regulator, and an operator. However, comprehensive regulatory frameworks, skilled workforces, establishments of a few supportive organizations, and laboratories for managing environmental radioactivity, radiological accidents, and radioactive wastes are yet to ready. Several suggestions are made for establishing and expediting radiation monitoring laboratories, a radiological emergency management center, a radioactive waste management company, and technical support organizations for the safety infrastructure. To avoid perceived risks, policymakers and competent authorities need to emphasize creating an optimized safety infrastructure before commissioning and operating the 1^st nuclear power plant safely, securely, and cost-sustainably.

• International Journal of Computer Science & Network Security
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• v.21 no.12
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• pp.349-355
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• 2021

The article investigates the conceptual principles of transformation of industrial parks into eco-industrial ones in the conditions of sustainable development. It is substantiated that the concept of sustainable development in the transformation of industrial parks is to grow industry and jobs, modernize production and introduce innovative technologies, resource and energy efficiency, reduce greenhouse gas emissions and waste storage, social protection of local communities and create favorable infrastructure. It is determined that for the transformation of industrial parks, it is necessary to improve regulatory changes, introduce criteria for compliance of industrial parks and the importance of their consideration, ensure park management by the management company and create favorable incentives for industrial entry into industrial symbiosis. It is proved that industrial parks can be an incentive for industrial development and competitiveness of enterprises. The availability of talented human capital, attractive territories, minerals, energy and mineral resources, developed domestic market, agricultural potential, transport networks is becoming an attractive place for investment and development. Industrial parks need investment. Transformation into eco-industrial parks through the implementation of sustainable development goals opens additional opportunities for access to investment funds and contributes to the implementation of growth and prosperity strategies of the country.

• East Asian Journal of Business Economics (EAJBE)
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• v.11 no.1
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• pp.31-40
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• 2023

Purpose - The prior literature indicated that green consumerism encouragements and programs have led to strict standards against environmental issues, thus reducing emissions from motors and engines and improving clean-burning energy options. The present study seeks to elaborate on the responsibility of ecological education in amplifying potential green consumers. Research design, Data, and methodology -The justification of the qualitative literature method used in this research is essential because, through the extensive explanation, justification and description of the methods used, researchers can enhance the trustworthiness of the research to a particular or designated audience. Result - Environmental education helps customers worldwide recognize the barriers to purchasing green products at every purchase level. Prior studies pointed out that after environmental education, consumers are much more willing to go greener in their consumption and safeguard the environment. Customers want to act green; however, they anticipate companies to lead the way. Conclusion - This research suggests that reusing prevailing resources creatively implies that fewer dollars are spent buying novel stock to generate green products. Although establishing a green company is expensive, it saves a lot of cash over time. Greening procedures can lead to efficiency gains by minimizing energy costs, permitting companies to acquire green tax credits.

• Nuclear Engineering and Technology
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• v.55 no.7
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• pp.2678-2686
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• 2023

This work demonstrates the results of full-scale numerical experiments of a hybrid thorium-containing fuel plant operating in a state close to critical due to a controlled source of D-T neutrons. The proposed facility represented a level of generated power (~10-100 MW_t) in a small pilot. In this work, the simulation of the D-T neutron plasma source operation in conjunction with the facility blanket was performed. The fission of fuel nuclei and the formation of spatial-energy release were studied in this simulation, in pulsed and stationary modes of the facility operation. The optimization results of neutronic and fluid dynamics studies to level the emerging offsets of the radial energy formed in the volume of the facility multiplying part due to the pulsed operation of the D-T neutron plasma source were presented. The results will be useful in improving the power control-based subcriticality monitoring method in coupled systems of the "pulsed neutron source-subcritical fuel assembly" type.