• International Journal of Fluid Machinery and Systems
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• v.6 no.1
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• pp.25-32
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• 2013

Data centers have been built with spread of cloud computing. Further, electric power consumption of it is growing rapidly. High power cooling small-sized fans; high pressure and large flow rate small-sized fan, are used for servers in the data centers and there is a strong demand to increase power of it because of increase of quantity of heat from the servers. Contra-rotating rotors have been adopted for some of high power cooling fans to meet the demand for high power. There is a limitation of space for servers and geometrical restriction for cooling fans because spokes to support fan motors, electrical power cables and so on should be installed in the cooling fans. It is important to clarify complicated internal flow condition and influence of a geometric shape of the cooling fans on performance to achieve high performance of the cooling fans. In the present paper, the performance and the flow condition of the high power contra-rotating small-sized axial fan with a 40mm square casing are shown by experimental and numerical results. Furthermore, influence of the geometrical shape of the small-sized cooling fan on the internal flow condition is clarified and design guideline to improve the performance is discussed.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.17 no.3
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• pp.212-223
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• 2007

18 Local exhaust ventilation systems in 10 melting companies located in an industrial complex were tested to know the status of maintenance. Test items were fan flowrates, fan static pressures, rotational speeds and differential pressures of bag filters. Only 22% of the tested fans has more than 80% flowrate efficiency. 44% of the fans has lower than 60% efficiency. The performance of the fans are not in a good status. For the fans with lower than 60% efficiency, the analysis shows that the lower flowrate might be caused by the degradation of fan performance. On the other hand, for the fan s with higher than 60% efficiency, the main cause of flowrate reduction might be too much pressure losses due to clogging of filter bags. The degradation of fans usually lead the reduction of hood capture efficiency, resulting in the increase of contaminant concentrations in workplace. To keep fans in good status, self inspections should be periodically conducted. This inspection should include the measurements of flowrate and pressures. The most important thing to be performed is the initial test of local exhaust ventilation system because the initial test data should be used to know the level of system degradation.

• Journal of Korean Tunnelling and Underground Space Association
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• v.15 no.3
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• pp.301-310
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• 2013

Jet fans are installed in road tunnels in order to maintain critical velocity when fire occurs. Generally the number of jet fans against fire are calculated by considering critical velocity and flow resistance by wall friction, vehicle drag force, thermal buoyance force and natural wind. In domestic case, thermal buoyance force is not considered in estimating the number of jet fans. So, in this study, we investigated the pressure loss due to the thermal buoyance force induced by tunnel air temperature rise and the impact of thermal buoyance force on the number of jet fans by the numerical fire simulation for the tunnel length(500, 750, 1000, 1500, 2000, 3500m) and grade (-1.0, -1.5, -2.0%). Considering the thermal buoyance force, number of jet fans have to be increased. Especially in the case of 100MW of heat release rate, the pressure loss due to thermal buoyance force exceed the maximum pressure loss due to vehicle drag resistance, so it is analyzed that number of 2~11 jet fans are needed additionally than current design criteria. Thus, in case of estimating the number of jet fans, it must be considered of thermal buoyance force induced tunnel air temperature rise by fire.

• Journal of the Korean Geographical Society
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• v.45 no.4
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• pp.431-443
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• 2010

The morphometric characteristics of 13 alluvial fans in the southern parts of the Korean Peninsula are studied and relationships between their distributions and causes are discussed by comparing them with 690 alluvial fans in Japan, Taiwan and the Philippines. The relationships between the surface gradient of alluvial fans and source basin area, the surface gradient and the relief ratio of the source basin, and the source basin area and the relief ratio were investigated. The alluvial fans in South Korea have typical characteristics of the Asian fans, although their frequency and density are relatively low, and the size and the relief ratio of their source basins are relatively small and steep, respectively. Moreover 36 major Korean river basins without alluvial fans tend to have lower altitude and relief ratios. Contrary to the argument by Blair and McPherson, the natural depositional gaps on the gradient of alluvial fans were not found. The Gyeongju alluvial fan is probably a fluvial fan with gentle gradient, whereas the other Korean fans seem to be debris-flow related on the base of their gradients.

• Journal of the Korean Society of Safety
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• v.29 no.5
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• pp.35-39
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• 2014

This paper is purposed to analyze the thermal characteristics of wiring according to the number of electric fans in operation for 10 fans over 10 year old and 10 fans less than 1 year old in livestock barn. In order to achieve the goal in the paper, it selected VCTFK, VFF, HIV, and CV wiring that were used most at 64 livestock barns in Cheongwon location through the research on the field investigation. Finally, it also analyzed the dangers by deducing the thermal characteristic data of 4 wiring. In addition, this paper suggested the mode of load current (the most frequently measured load current) of both over 10 years old and less than 1 year old electric fans. The data of this paper could be used for the maintenance and management of wiring and fire investigation of livestock barn as well as for materials of safe designs of wiring of electric fans.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.19 no.10
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• pp.695-702
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• 2007

In this paper, the ventilation efficiencies of an underground sewage disposal plant were investigated for ventilating system without fan, ventilating system with eleven cross flow fans and ventilating system with sixteen cross flow fans by numerical method. It has been found that the air change effectiveness of the system without fan was predicted 0.44. It means that an additional ventilating equipment is needed to maintain good indoor air quality. For the ventilating system with sixteen cross flow fans, the air change effectiveness was predicted 0.55. The air change effectiveness of the ventilating system with eleven cross flow fans was predicted 0.51. It is known that the air change effectiveness above 0.5 is enough to eliminate pollutant and bad smell in the indoor. Therefore, it is recommended to select the ventilating system with eleven cross flow fans for the underground sewage disposal plant in an economic point of view.

• Journal of Sport and Applied Science
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• v.4 no.2
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• pp.45-51
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• 2020

Purpose: The purpose of this study is to investigate how sports fans' loyalty is built via CSR activities of professional sports teams. Furthermore, the study sought to suggest the model presenting the process of developing loyalty of sport fans by teams' CSR performance. Research design, data, and methodology: For this purpose, a survey was conducted on 450 professional sports fans through the convenience sampling method. A total of 357 of the data were used for the final analysis. Based on the collected data, frequency analysis, reliability analysis, confirmatory factor analysis, and structural equation model analysis were conducted. Results: The results showed that CSR activities contribute to building a positive image of team. Regarding fan identification, team image has also a positive effect on enhancing identification. The finding has supported the notion that attitudinal loyalty is enhanced by fan identification and further attitudinal loyalty significantly influences behavioural loyalty of fans. Conclusions: The results of this study explored the function of CSR of the teams on attitudinal and behavioural outcomes, loyalty. Moreover, the study suggested the constructual model presenting its role on enhancing fans' attitudes and behaviour affecting participation and consumption. Academic and practical implications were discussed for sport marketers and practitioners.

• Korean Journal of Computational Design and Engineering
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• v.11 no.4
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• pp.246-255
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• 2006

Ribs and fans are interesting geometric entities that are derived from an ordinary $B\'{e}zier$ curve or surface. A rib itself is a $B\'{e}zier$ curve or surface with a lower degree than the given curve or surface. A fan is a vector field whose degree is also lower than its origin. First, we present methods to transform the control points of a $B\'{e}zier$ curve or surface into the control points and vectors of its ribs and fans. Then, we show that a $B\'{e}zier$ curve of degree n is decomposed into a rib of degree (n-1), a fan of degree (n-2), and a scalar function of degree 2. We also show that a $B\'{e}zier$ surface of degree (m, n) is decomposed into a rib of degree (m-1, n-1) and three fans of degrees (m-1, n-2), (m-2, n-1), and (m-2, n-2), respectively. In addition, the lengths of the fans are further controlled by scalar functions of degree 2 and (2, 2). We present relevant notations and definitions, introduce theories, and present some of design examples.

• Journal of Distribution Science
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• v.19 no.9
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• pp.113-123
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• 2021

Purpose: BTS Meal at McDonald's was launched in May 2021 in selected countries all over the world. BTS fans in Indonesia bought the BTS Meal and collectively donated to the online delivery drivers as a form of empathy. As a quantitative study, this paper aims to identify the influencing factors in sociopsychology for fans to buy products (BTS Meal) available online using celebrity endorsement strategy, as well as demonstrating social empathy as an extended effect. Research design, data and methodology: empirical research was conducted through an online survey sent to 150 participants using the purposive sampling method. Participants were BTS fans, or ARMYs, who bought BTS Meal and conducted donations. Data were then sorted and processed with path regression. Results: preference and role model influenced the buying behavior; however, these factors influenced social empathy only when mediated by consumption. Preference and role model alone did not have a direct influence on social empathy. Conclusions: Consumer behavior insight is relevant in distribution science. A meal distribution involving brand ambassadors is considerable, particularly with celebrities demonstrating quality in capturing fans' hearts through role modeling. When a distribution is conducted online using a brand ambassador, buying behavior could lead to a social impact.

• Journal of Sport and Applied Science
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• v.6 no.2
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• pp.9-18
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• 2022

Purpose: This research aims to analyze the relationship marketing between football club organizations, players, and the fans club community. Research design, data, and methodology: An ethnographic approach was used to observe for eight months in the community, interviews, and documents analysis in Bonek Mania community fans club and Persebaya, a football club management in Surabaya, Indonesia. Results: The results show that the management of the football club has maintained the football high-end brand image in the national league. Stakeholders have endeavored to build the values and shared meaning with the public and cohesively with Bonek Mania. The struggles and achievements are intended to maintain the local collective memory of Surabaya's patriotism as the "city of heroes." Sustainable relationships were built by professional football club managers, players, and the fans club to foster the spirit, economic resources, and sustainable development. Conclusions: This research implies that it can provide direction for the management of football clubs by paying attention to relationship marketing, developing unique local values to build the customers' loyalty. Further implications were discussed.