• Journal of Drive and Control
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• v.21 no.2
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• pp.15-22
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• 2024

The objective of this study was to examine whether a gerotor pump used in a transmission could be converted into an electric vehicle thermal management system pump using a virtual design environment. To achieve this objective, we first built an environment that could analyze the performance of a gerotor pump in heat transfer fluid. Flow rate, pressure, and volumetric efficiency were then analyzed when using heat transfer fluid in a gerotor pump. Finally, how large the displacement volume of the pump should be designed when using a heat transfer fluid other than oil was determined. Based on results of this study, it is expected that gerotor pumps will be applied to new business fields such as electric vehicle cooling systems.

• Geophysics and Geophysical Exploration
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• v.13 no.1
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• pp.80-87
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• 2010

This study was conducted to develop a reservoir modelling workflow to reproduce the heterogeneous distribution of effective permeability that impacts on the performance of SAGD (Steam Assisted Gravity Drainage), the in-situ bitumen recovery technique in the Athabasca Oil Sands. Lithologic facies distribution is the main cause of the heterogeneity in bitumen reservoirs in the study area. The target formation consists of sand with mudstone facies in a fluvial-to-estuary channel system, where the mudstone interrupts fluid flow and reduces effective permeability. In this study, the lithologic facies is classified into three classes having different characteristics of effective permeability, depending on the shapes of mudstones. The reservoir modelling workflow of this study consists of two main modules; facies modelling and permeability modelling. The facies modelling provides an identification of the three lithologic facies, using a stochastic approach, which mainly control the effective permeability. The permeability modelling populates mudstone volume fraction first, then transforms it into effective permeability. A series of flow simulations applied to mini-models of the lithologic facies obtains the transformation functions of the mudstone volume fraction into the effective permeability. Seismic data contribute to the facies modelling via providing prior probability of facies, which is incorporated in the facies models by geostatistical techniques. In particular, this study employs a probabilistic neural network utilising multiple seismic attributes in facies prediction that improves the prior probability of facies. The result of using the improved prior probability in facies modelling is compared to the conventional method using a single seismic attribute to demonstrate the improvement in the facies discrimination. Using P-wave velocity in combination with density in the multiple seismic attributes is the essence of the improved facies discrimination. This paper also discusses sand matrix porosity that makes P-wave velocity differ between the different facies in the study area, where the sand matrix porosity is uniquely evaluated using log-derived porosity, P-wave velocity and photographically-predicted mudstone volume.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.10
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• pp.144-149
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• 2020

Bubble reduction devices are intended to solve problems related to the quantitative supply of oil. Therefore, in this study, numerical analysis was conducted to verify the flow characteristics of bubble particles during the operation of a bubble reduction device. As a result of the basic analysis, the area where the rise and fall of bubbles were most active was found, and numerical calculations were performed focusing on the points. Before the numerical calculations, a non-dimensional derivation was performed to secure homogeneity among the variables. Based on the data obtained from non-dimension derivation, 25 variable conditions for each particle size and fluid velocity were set. Through separate calculations, the equation for bubble rise and fall was derived. By calculating the ratio of drag and buoyancy for each variable, if the drag force acting on the bubble was greater than buoyancy, the bubble falls, and bubbles are not reduced. If the buoyancy is larger than drag, the bubble rises, and the bubble is reduced. Through the analysis, the rise and fall of the bubble were confirmed, and the results were consistent with the separate numerical calculations.

• Journal of Radiation Protection and Research
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• v.33 no.1
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• pp.35-40
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• 2008

A distillation tower is one of the important facilities which separates and refines a crude oil stream according to certain boiling points. Its operation efficiency can affect the productivity of a refinery substantially. The objective of this study is to elucidate some operational information on the internal conditions of a distillation tower from a measurement of density profile by using a sealed gamma-ray source and a radiation detector. Gamma radiation counts were measured by a BGO detector positioned diametrically outside the tower-wall, opposite to the gamma source(Co-60) as the detector and the source were lowered concurrently. From the results, structural abnormality of the trays was not found inside the tower. Considering the flow distribution patterns, however, a vapor phase was dominantly formed at the upper part of the tower and a liquid phase at the lower part. From the gamma scanning of the distillation tower, it is anticipated that the gamma absorption technique can be used as an important tool for confirming the structural soundness of trays and investigating flow distribution in refinery facilities.

• Journal of the Economic Geographical Society of Korea
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• v.1 no.1
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• pp.57-74
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• 1998

Recently. the interest in Physical distribution has increased in economic geography This paper aims to review and prospect the internatonal physical distribution studies of international trade and international freight flows. And it has examined the changes in methodology of international physical distribution. Author has defined international physical distribution as the physical distribution of international trade and international freight flow The results are as follows : (1) As the methodology of international physical distribution studies developes, the physical distribution should be recognized not only as transportation phenomenon but also as total logistics which is understood as the combination of production and consumption including information flow. (2) The studies about model of international physical distribution flow ill need to study regional relations including urban, in the future. And economic geography and location theory adding culture and behaviour elements will be restructured, because not only state but also multinational corporation appear as trade subject in global economy. (3) The studies for the relation of habor and its hinterland in Physical distribution need to analyze the factors causing habor use with decision-making behaviour of corporation. (4) After oil crisis. as air freight is important, the studies for hinterland and foreland of freight centering international airport are needed because of necessity of light and small freight. flexible Production system, free trade, and high speed freight transportation of freshing food and flowers and so forth.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.39 no.11
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• pp.1123-1129
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• 2015

A pair of two-way valves typically is used in automotive washing machines, where the water flow direction is frequently reversed and highly pressurized clean water is sprayed to remove the oil and dirt remaining on machined engine and transmission blocks. Although this valve system has been widely used because of its competitive price, its application is sometimes restricted by surging effects, such as pressure ripples occurring in rapid changes in water flow caused by inaccurate valve control. As an alternative, one three-way reversing valve can replace the valve system because it provides rapid and accurate changes to the water flow direction without any precise control device. However, a cavitation effect occurs because of the complicated bottom plug shape of the valve. In this study, the cavitation index and percent of cavitation (POC) were introduced to numerically evaluate fluid flows via computational fluid dynamics (CFD) analysis. To reduce the cavitation effect generated by the bottom plug, the optimal shape design was carried out through a parametric study, in which a simple computer-aided engineering (CAE) model was applied to avoid time-consuming CFD analysis and difficulties in achieving convergence. The optimal shape design process using full factorial design of experiments (DOEs) and an artificial neural network meta-model yielded the optimal waist and tail length of the bottom plug with a POC value of less than 30%, which meets the requirement of no cavitation occurrence. The optimal waist length, tail length and POC value were found to 6.42 mm, 6.96 mm and 27%, respectively.

• Journal of Ocean Engineering and Technology
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• v.33 no.4
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• pp.350-357
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• 2019

The development of marine technology is expected to increase the demand for marine plants because of increasing oil prices. Therefore, there is also expected to be an increase in the demand for cylindrical structures such as URF (umbilical, riser, flowline) structures and spars, which are used operating in various seas. However, a cylindrical structure experiences vortex induced motion (VIM) in a current. In particular, for risers and umbilicals, it is important to identify the characteristics of the VIM because interference between structures can occur. In addition, various studies have been conducted to reduce VIM because it is the cause of fatigue damage to structures. The helical strake, which was developed for VIM reduction, has an excellent VIM reduction performance, but is difficult to install on structures and has a negative effect on heave motion. Therefore, the purpose of this study was to supplement the shortcomings of the helical strake and develop a high-performance reduction device. In the reduction device developed in this study, a string is placed around the structure inside the flow, causing vibration. The vibration of this string causes a small turbulence in the flow field, reducing the VIM effect on the structure. Finally, in this study, the 2-DOF motion characteristics of models without a suppression device, models with a helical strake, and models with a string were investigated, and their reduction performances were compared through model tests.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.35 no.6
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• pp.631-638
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• 2022

Microgrid, which enables the production and consumption of electricity to be done independently on a small scale, has been studied on one of the solutions of reinforcement for flexibility of electronic system. This study examined the application effect of new microgrid by applying hybrid battery in electric power storage device. We designed the system to highlight the advantage of each battery and complement the disadvantage by using hybrid system with Lithium-ion battery and interval Redox flow battery. It runs with lithium-ion battery during the initial startup while the Redox flow battery operates for a long time at the end of excessive period, and it enables a discharge of Lithium-ion and Redox flow battery at the same time when the load has a large output. We chose Maldives as a subject of this study for organizing and optimizing independent microgrid. Maldives is the country to accomplish 100% domestic electricity in South Asia, but the whole electric power is supplied through diesel generation imported fossil fuel. We organized and optimized microgrid for energy independence on Malahini island to solve Maldives energy cost problem and global energy environment matters. We analyzed the daily power supply and accumulated the power supply from September 18, 2018~February 11, 2019. The accumulated power supply was about 120.4 MWh and the daily power supply was about 800~1000 kWh. Based on the collected information, we divided the cases into three models which are only diesel generator, solar generator as well as diesel generator, and solar+ESS+diesel generator. We analyzed the amount of oil consumption compared to the cost of construction and power output. The result showed that solar+ESS+diesel generator was most economically feasible. As well, we obtained that our considering hybrid battery system reduced the fuel consumption for diesel power generation about 10~15%.

• Journal of Energy Engineering
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• v.17 no.3
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• pp.139-144
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• 2008

Recently due to march as the high oil price, It is necessary for Korea to grope a plan, which is to increase the energy efficiency of existing facilities as well as to develop overseas gas and oil resources. With this point, this work carried out to approach the high pressure LNG pipeline network of Inchon receiving terminal with Newton method as corrective flowrate. We found that the high pressure network mainly depends on FCVs(Flow Control Valves). The high pressure pump showed the maximum efficiency at the FCVs of 50% opening and could discharge LNG only above the LNG head of 1,500m from a system curve obtained. The operating cost of pumps was estimated from their operating points. We compared the operating cost under normal operation with the operating cost under maximum efficiency. Especially, we obtained the day savings of a year as wells as the hour savings of a day. From the results, the high pressure network win be able to reduce the operating cost of 138 million wons in a year. This means that a pump can reduce the operating cost of 9,823 thousands won. Consequently, this work could find the operating features of the pumps under the complicated high pressure LNG network and the savings effect of the pump operating cost. Also, the results will be able to macroscopically contribute the heightening of national energy competitiveness as well as to microscopically contribute the future effective operation of LNG receiving terminal.

• The Journal of Industrial Distribution & Business
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• v.9 no.12
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• pp.55-61
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• 2018

Purpose - It suggests that making a policy and strategies for a way of Dubai has a strong priority strategy on science and technology by using much oil dollars to prepare risk when oil dollar's decrease. This has been now investigated how the leading innovator has changed the periphery countries. Research design, data, and methodology - Analyze policy, status, what other neighbouring Middle East countries also want to benchmark a successful case of a leading Dubai strategy. Higher manpower is needed absolutely to develop S&T. and etc. Dubai and Arab countries establish university to nurture as well as invite the talented manpower from overseas to recover deficient manpower. Dubai built totally academy city and invited branch of the overseas famous university, and Saudi Arabia built university(KAUST) and invite faculty and support good scholarship for students. Abrab countries especially, This is studied the process of differentiating and integrating the migrant workers of these cities into the globalized cities. This has resulted in large-scale employment for foreign and local companies in these cities and the spread of science and innovation. Results - Dubai supports venture or SMEs by using a strong priority strategy and attracts foreigner's investor, with which the neighbouring countries have been preparing together for 4th wave. It demonstrates that the gravitational model has been activated from neighboring countries of innovation science to create Dubai's hub. The maturity of long-term urban innovation is related to innovation capability through the national response and review. As a result, the flow of skilled international migration has been localized because of the mutual intersection with the local employment structure, and the development has spread as it spreads to neighboring countries. Conclusion - For the exploiting of new Distribution market in the neighbouring countries, Middle East countries' a strong priority strategy on S&T and education system give an influence on economic situation of the 4th wave in the world and world order of leading by USA, Japan, or EU, and etc. This is due to the creation of clusters in the form of SEZs, friendly industrial policies and world-class infrastructure and innovation development. Its neighbours benchmark the cases of distribution of science innovation and centralizes the surrounding people.