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A Study on the Physical Characteristics of Grout Material for Backfilling Ground Heat Exchanger (지중 열교환기용 뒤채움재의 물리적 특성 연구)

  • Choi, Hang-Seok;Lee, Chul-Ho;Choi, Hyo-Pum;Woo, Sang-Baik
    • Journal of the Korean Geotechnical Society
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    • v.24 no.1
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    • pp.37-49
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    • 2008
  • A geothermal heat pump system is a preferable alternative energy system in Korea because it uses the heat energy of the earth, which is environmentally friendly and inexhaustible. In order to characterize the thermal conductivity and viscosity of grout materials used for backfilling ground heat exchangers, nine bentonite grouts, one marine clay from Boryung, and cement grouts adapted in the United State have been considered in this study. The bentonite grouts indicate that the thermal conductivity and viscosity increase with the content of bentonite or filler (silica sand). In addition, material segregation can be observed when the viscosity of grout is relatively low. The marine clay turns out to be unsuitable for backfilling the ground heat exchanger due to its insufficient swelling potential. The saturated cement grouts appear to possess much higher thermal conductivity than the saturated bentonite grouts, and the reduction of thermal conductivity in the cement grouts after drying specimens is less than that in the case of the bentonite grouts. Maintaining the moisture content of grouts is a crucial factor in enhancing the efficiency of ground heat exchangers.

SNU 1.5MV Van de Graaff Accelerator (IV) -Fabrication and Aberration Analysis of Magnetic Quadrupole Lens- (SNU 1.5MV 반데그라프 가속기 (IV) -자기 4극 렌즈의 제작과 수차의 분석-)

  • Bak, H.I.;Choi, B.H.;Choi, H.D.
    • Nuclear Engineering and Technology
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    • v.18 no.1
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    • pp.1-8
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    • 1986
  • A magnetic quadrupole doublet was fabricated for use at the pre-target position of SNU 1.5MV Van de Graaff accelerator and then its optical characteristics were measured and analysed. The physical dimensions are: pole length 180mm, aperture radius 25mm, pole tip radius 28.75mm. Material for poles and return yokes is carbon steel KS-SM40C. Coils have 480 turns per one pole and air-cooling is adopted. Applying the d.c. current 2.99$\pm$0.03A to the lens, and using the Hall probe, magnetic field elements $B_{\theta}$ , $B_{\gamma}$, were measured at the selected Points along each coordinate direction r,$\theta$, z. From the area integration and orthogonal polynomial fitting for the measured data, the magnetic Field gradient G=566.3$\pm$2.1 gauss/cm at lens center, the effective length L=208.3$\pm$1.44mm along the lens axis have been obtained. The harmonic contents were determined up to 20-pole from the generalized least squares fitting. The results indicate that sextupole/quadrupole is below 1.4$\pm$0.9% and all the other multipoles are below 0.5% in the region within 18mm radius at the center of lens.

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The effects of knowledge management strategy on the management performance in the hotel industry (호텔기업의 지식경영전략이 경영성과에 미치는 영향)

  • Kim, Hyoung-Gu;Son, Jae-Young;SunWoo, Young-Soo
    • Journal of the Korea Society of Computer and Information
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    • v.14 no.3
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    • pp.227-235
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    • 2009
  • The ultimate goal of hotel corporations is to maintain their existence by securing competitive advantages over their competitors. In order to secure competitive advantages, they need to shed off the conventional paradigm of company management, which increasingly grows weaker as the industrial society turns into a knowledge-based one, and make effective use of knowledge, which is the core source of their wealth and competitiveness, in their management. Thus this study set out to identify knowledge management strategy to result in great management performance to hotel corporations. It also aimed to suggest specific action plans for them to do knowledge management efficiently based on the results. The causal relations between the knowledge management strategy and management performance were examined to figure out the former's influences on the latter. As a result, Two types of knowledge management strategy seemed to have positive(+) impacts on competitive advantages, but negative(-) impacts on financial performance.

Gaze and Gender Dynamics of Portrait of a Lady on Fire (<타오르는 여인의 초상>의 시선과 젠더의 동학)

  • Kwon, Eunsun
    • The Journal of the Convergence on Culture Technology
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    • v.8 no.3
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    • pp.399-404
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    • 2022
  • Céline Sciamma is a leading female director of her time. She is constantly making works on the subject of women. It can be said that it has pioneered a 'female narrative'. In particular, it shows a unique perspective in dealing with the complexities surrounding the formation of a girl's sexual identity and the influence of peer culture on individuals. In Portrait of a Lady on Fire, 'The Handmaiden', 'The Painter', and 'The Maid' show the solidarity of women without hierarchies in a liberated space where the patriarch is absent, showing a feminist interpretation of classics and a self-reflecting consciousness of women's historical records. Based on the setting of drawing, this film explores the genderization of gaze, gaze and objectification, issues of seeing and power, etc. constructed throughout the history of visual arts. The portrait work of Heloise and Marianne in the film deconstructs the formula of 'a male painter as a viewer and a female model who gazes at herself through the male gaze' and turns the gaze into an interactive process of giving and receiving. The process of exchanging gazes is sealed with a nude painting in which Marianne's face is superimposed on Heloise's body. This overturns the nude painting as the dominant form of engraving the male audience's position in the image through the stylization of the viewing method in the history of Western painting with the erotic gaze of a lesbian in an instant.

Development of 3-D Nonlinear Wave Driver Using SPH (SPH을 활용한 3차원 비선형 파랑모형 개발)

  • Cho, Yong Jun;Kim, Gweon Soo
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.28 no.5B
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    • pp.559-573
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    • 2008
  • In this study, we newly proposed 3-D nonlinear wave driver utilizing the Navier-Stokes Eq. the numerical integration of which is carried out using SPH (Smoothed Particle Hydrodynamics), an internal wave generation with the source function of Gaussian distribution and an energy absorbing layer. For the verification of new 3-D nonlinear wave driver, we numerically simulate the sloshing problem within a parabolic water basin triggered by a Gaussian hump and uniformly inclined water surface by Thacker (1981). It turns out that the qualitative behavior of sloshing caused by relaxing the external force which makes a free surface convex or uniformly inclined is successfully simulated even though phase error is visible and an inundation height shrinks as numerical simulation more proceeds. For the more severe test, we also simulate the nonlinear shoaling and refraction over uniform beach of wedge shape. It is shown that numerically simulated waves are less refracted than the linear counterpart by Hamiltonian ray theory due to nonlinearity, energy dissipation at the bottom and side walls, energy loss induced by breaking, and the hydraulic jump occurring when breaking waves encounter a down-rush by the preceding wave.

A Site Selection of Public Facility Based on An Accessibility Theory & GIS Spatial Analysis Technologies (접근성이론과 GIS 공간분석기법을 활용한 행정기관의 입지선정)

  • Kim, Hwang Bae;Kim, Sigon
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.26 no.3D
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    • pp.385-391
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    • 2006
  • It is very important to make a decision for locating public facility site in a objectively way people in general agree with. This is because public facility affects not only daily life of people in there but also a regional development. This paper sets up a site selection model which utilize an accessibility theory and GIS spatial analysis techniques. This model has been applied to all the twelve alternatives of Chungnam Provincial Office (CPO) sites which are well known to the public. On the criterion of average access time from all the other areas in Chungnam Province, CH alternative is found to be the best one followed by CH/AS, AS alternatives. On the basis of total people-travel time CH/AS alternative turns out to be the best one followed by CH, AS alternatives. In conclusion top three best locations for CPO are CH and AS area where transportation facility are in good condition and population density is highest in Chungnam Province. This fact implies that a transportation accessibility and population density are the primary key in determining the location of public facility.

Seniors' Job Programme and User Involvement in Policy-making and Implementation Process (노인일자리사업 정책결정·집행과정에서의 '이용자 참여'에 관한 연구)

  • Yang, Yunjeong;Chung, Youngsoon
    • 한국노년학
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    • v.31 no.4
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    • pp.885-903
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    • 2011
  • This study aims at examining the extent to which older people participating in the Seniors' Job Programme do involve in policy-making and implementation processes of the programme. The study is based on qualitative interviews with seven experts among those involved in the policy process in District A of Seoul. They include civil servants of central and local governments and social workers of implementing bodies such as seniors' welfare centres and job centres. The results show that firstly, practically no direct involvement of participants is being made at the policy-making level, due mainly to the traditional top-down approach of policy process in Korea and also to prejudices of public servants concerned on the current senior citizens' capability as contributor to public policy-making. User-involvement is being made, however, at the implementation level: participants are making, although minor, suggestions for improvements of working conditions and they are being listened to by frontline social workers. Support by the implementing institutions turns out to be necessary for this. Lastly, in contrast with the present, many interview participants are expecting a more active participation from the future generation, i.e. the baby-boom generation when they would have retired. The study concludes by calling for enhancement of institutional and capacity-building support for active user involvement in the future.

Gender, A Neglected Variable: An Analysis of a Gender Gap in Voter Turnout (여성, 간과된 변수: 투표율에서의 성차(Gender Gap) 분석)

  • Koo, Bon Sang
    • Korean Journal of Legislative Studies
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    • v.27 no.1
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    • pp.5-40
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    • 2021
  • This study attempts to analyze gender gaps in voter turnout for three different types of elections held since 2017 at the aggregate level using the Central Election Management Commission's turnout data, paying attention to the importance of women's voting. The findings are as follows. First, modern gender gaps in voter turnout at the aggregate level are confirmed in most regions regardless of election types. Second, the gender gap in turnout varies with age. The gender difference is verified in the "widowhood effect," where turnout decreases in the oldest-old. In the new voter group, modern gender gaps appear in most regions. The reversed gender difference in turnout in the late 20s, which reflects the Korean society's characteristics, is confirmed in all elections. Third, it is unclear whether the reverse gender gap in turnout becomes more pronounced in urbanized districts. As urbanization progressed, modern gender differences in voter turnout across age groups are observed at the population-based size level. Paradoxically, the modern gender gap tends to be weak and turns into the traditional gender gap in younger age groups (in the late thirties) in Gangnam-gu and Seocho-gu, the most modernized districts in Seoul. These results show that the modern gender gap in turnout is now a common phenomenon and continues to be strengthened by newly recruited voters in Korea. Thus we should pay more attention to female voters' political behavior and a new approach beyond the developmental theory to understand the causal mechanism to generate the modern gender gap in voter turnout.

Posttraumatic growth in patients with cancer (암환자의 외상후성장에 영향을 미치는 요인에 관한 연구)

  • Han, In Young;Lee, In Jeong
    • Korean Journal of Social Welfare Studies
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    • v.42 no.2
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    • pp.419-441
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    • 2011
  • Cancer is a disease that threatens the individual's life. This is why the cancer patient goes through psychosocial pain in the form of a trauma. Thus, the previous researches have only focused on the cancer patient's psychosocial distress. However, the cancer patients who have grown more mature and brought upon positive changes in their lives have been clinically observed. Because of this, researches regarding the ways that social welfare can intervene in order to examine the cancer patients' positive changes and growth which breaks away from the previous pathological point of view of the cancer patients are being actively conducted in other countries. But it turns out that there aren't enough basic researches related to this topic and thereby the need to lay out the basis for social welfare intervention. Therefore, this research examines positive changes and growth that may result from the traumatic experience of having a cancer. The predictable factors regarding this are analyzed in order to provide the basic information that may promote clinical intervention for cancer patient's posttraumatic growth. For this, the information from 206 cancer patients who have agreed to participate in the research have been used to predict and evaluate the predictable factors for the cancer patient's post-traumatic growth and hierarchy multiple regression haven been analyzed. As the result of the research, main factor of the post-traumatic growth is found to be social support and coping. The positive reconstruction of coping has been discovered to be the strongest predictable factor for cancer patient's posttraumatic growth. Based on this result, the advice for further research and implications for social welfare have been given.

Improvement of Multiple-sensor based Frost Observation System (MFOS v2) (다중센서 기반 서리관측 시스템의 개선: MFOS v2)

  • Suhyun Kim;Seung-Jae Lee;Kyu Rang Kim
    • Korean Journal of Agricultural and Forest Meteorology
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    • v.25 no.3
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    • pp.226-235
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    • 2023
  • This study aimed to supplement the shortcomings of the Multiple-sensor-based Frost Observation System (MFOS). The developed frost observation system is an improvement of the existing system. Based on the leaf wetness sensor (LWS), it not only detects frost but also functions to predict surface temperature, which is a major factor in frost occurrence. With the existing observation system, 1) it is difficult to observe ice (frost) formation on the surface when capturing an image of the LWS with an RGB camera because the surface of the sensor reflects most visible light, 2) images captured using the RGB camera before and after sunrise are dark, and 3) the thermal infrared camera only shows the relative high and low temperature. To identify the ice (frost) generated on the surface of the LWS, a LWS that was painted black and three sheets of glass at the same height to be used as an auxiliary tool to check the occurrence of ice (frost) were installed. For RGB camera shooting before and after sunrise, synchronous LED lighting was installed so the power turns on/off according to the camera shooting time. The existing thermal infrared camera, which could only assess the relative temperature (high or low), was improved to extract the temperature value per pixel, and a comparison with the surface temperature sensor installed by the National Institute of Meteorological Sciences (NIMS) was performed to verify its accuracy. As a result of installing and operating the MFOS v2, which reflects these improvements, the accuracy and efficiency of automatic frost observation were demonstrated to be improved, and the usefulness of the data as input data for the frost prediction model was enhanced.