• Title, Summary, Keyword: Down Cut

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Behavior Characteristics of Precast Concrete-Panel Retaining Wall Adhered to In-situ Ground through Large Scaled Load Test (대형재하시험을 통한 원지반 부착식 패널옹벽의 거동특성)

  • Shin, Yuncheol;Min, Kyongnam;Kim, Jinhee;Ahn, Taebong
    • Journal of the Korean Geoenvironmental Society
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    • v.17 no.11
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    • pp.45-53
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    • 2016
  • A precast panel wall system resists against the horizontal earth pressure by increasing the shear strength of ground by reinforcement connected to the panel. The application of precast panel wall system is growing to lately minimize the earth work and environmental damage caused by large cut slope and to use the limited land effectively. The ground adhered panel wall system is the construction method that has the panel engraved with natural rock shape to improve the landscape. This system is developed to complete Top-Down method, and it is possible to have vertical cut, and to adhere to in-situ ground, improve construction ability by minimizing the ground relaxation and exclusion the trench and backfill process. In this study the field tests were performed to verify the construction ability about the vertical cut and complete Top-Down process and the construction behavior of ground adhered panel wall system was analyzed by large scale loading test and measurement results during loading test.

The Effect on the Knowledge, Perception of Drinking Cultures, Drinking Problems of University Students by Cut Down Drinking Circle Activity (절주동아리 활동이 대학생의 음주에 대한 지식, 음주문화 인식도, 음주 문제에 미치는 효과)

  • Kim, Seung-Dae;Jeong, Myeong-Ae
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.13 no.9
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    • pp.4090-4097
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    • 2012
  • The purpose of this study was performed to evaluate the effect of the cut down drinking circle activity on knowledge, perception of drinking cultures and drinking problem to the university students. Study period was from April to November. The participants of this study included 95 university students, located in the adjoining region of K city. While one of the group, composed of 47 students was designated as an experimental group, and the other group, composed of 48 students, was compared as a control group. Data analysis was done using ${\chi}^2$-test, t-test, they were processed SPSS 17.0. For homogeneous, general character, knowledge of drinking, perception of drinking cultures, drinking problem were measured pretest. The result were homogeneous group. The findings in this research were as follows. Knowledge of cut down drinking circle activity was significant difference between the two groups. On the other hand, the effect on perception of drinking cultures and drinking problem were not significantly different. These findings in the study give us the necessity of the cut down drinking circle activity for university students. It is also meaningful for this program to apply university students to various programs of alcohol-related problems.

Effects of the Tool Path on the Geometric Characteristics of Milled Surface (가공경로가 밀링가공면의 기하학적 특성에 미치는 영향)

  • Park, Moon-Jin;Kim, Kang
    • Journal of the Korean Society for Precision Engineering
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    • v.15 no.6
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    • pp.58-63
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    • 1998
  • There are lots of factors that are related to the geometric characteristics of machined surface. Among them, the tool path and milling mode (up cut milling or down cut milling) are the easiest controllable machining conditions. Thus, the first objective of this research is to study the effects of them on the milled surface that is generated by an end milling tool. To get precision parts, not only the machining process but also the measurement of geometric tolerance is important. But, this measurement requires a lot of time, because the infinite surface points must be measured in the ideal case. So, the second objective is to propose a simple flatness measurement method that can be available instead of the 3-D geometric tolerance measurement method, using a scale factor and characterized points. Finally, it is also shown that the possibility of flatness improvement by shifting the consecutive fine cutting tool path as compared with the last rough cutting tool path.

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A Study on the Critical Depth of Cut in Ultra-precision Machining (초정밀 절삭에 있어서 임계절삭깊이에 대한 연구)

  • Kim, Kug-Weon
    • Journal of the Korean Society for Precision Engineering
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    • v.19 no.8
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    • pp.126-133
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    • 2002
  • The cutting thickness of ultra-precision machining is generally very small, only a few micrometer or even down to the order of a few nanometer. In such case, a basic understanding of the mechanism on the micro-machining process is is necessary to produce a high quality surface. When machining at very small depths of cut, metal flow near a rounded tool edge become important. In this paper a finite element analysis is presented to calculate the stagnation point on the tool edge or critical depth of cut below which no cutting occurs. From the simulation, the effects of the cutting speed on the critical depths of cut were calculated and discussed. Also the transition of the stagnation point according to the increase of the depths of cut was observed.

Study on the Application of Semi-open cut Top-Down Construction for Framework (세미 오픈컷 역타공법의 현장적용에 관한 연구)

  • Sho, Kwang-Ho
    • Journal of the Korean Association for Spatial Structures
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    • v.11 no.2
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    • pp.129-138
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    • 2011
  • Construction methods for underground structure are classified as bottom-up, up-up, and top-down methods depending on the procedure of construction related to a superstructure. In top-down construction methods, building's main structure is built from the ground level downwards by sequentially alternating ground excavation and structure construction. In the mean time, the main structure is also used as supporting structure for earth-retaining wall, which results in the increased stability of the earth-retaining wall due to the minimized deformation in adjacent structures and surrounding grounds. In addition, the method makes it easy to secure a field for construction work in the downtown area by using each floor slabs as working spaces. However top-down construction method is often avoided since an excavation under the slab has low efficiency and difficult environment for work, and high cost compared with earth anchor method. This paper proposes a combined construction method where semi-open cut is selected as excavation work, slurry as earth -retaining wall and CWS as top-down construction method. In the case study targeted for an actual construction project, the proposed method is compared with existing top-down construction method in terms of economic feasibility, construction period and work efficiency. The proposed construction method results in increased work efficiency in the transportation of earth and sand, and steel frame erection, better quality management in PHD construction, and reduced construction period.

GROUNDWATER POLLUTION CONTROL IN UNCONTROLLED WASTE LANDFILLS (폐기물 매립지 지반내에서의 지하수오염제어)

  • Lee, Gwang-Yeol;Jang, Yeon-Su;Han, Il-Yeong
    • Proceedings of the Korean Geotechical Society Conference
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    • pp.75-82
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    • 1994
  • Groundwater in waste landfills can be contarninated by leachates produced from wastes and flow down toward rivers. These accidents are easily discovered in uncontrolled landfill sites. In this study, applications for controlling groundwater pollution and protecting river pollution were studied using installation of cut-off walls around the waste landfill. Analyses for the efficiency and applicability of the cut-off wall were made under environmental, economical anc technical considerations. Cut-off walls were installed at the upgradient and the downgradient. prediction analyses for the hydraulic head distribution over the site were made for concerning with the final cover and without the final cover. Also, the hydraulic head distribution was predicted with well-pumping on both cases, upgradient cut-off wall and downgradient cut-off wall.

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A Study on the Optimum Finish Allowance for Machining Accuracy Improvement in the End Milling Processes (엔드밀 가공의 정밀도 향상을 위한 최적정삭여유에 관한 연구)

  • 최종근;김형선;김성초
    • Transactions of the Korean Society of Machine Tool Engineers
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    • v.13 no.3
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    • pp.8-15
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    • 2004
  • A significant error in the end milling processes is generated due to using slender tools of which the strengths are not sufficient. In order to obtain the desired machining accuracy, therefore, it is general that at first the rough cut is implemented, then the finish cut is followed. The rough cut eliminates large volume and the finish cut does the remained part. This remaining portion after the rough cut is called as the finish allowance. Larger finish allowances make it hard to get precise dimensions at a following finish cut. Smaller finish allowances are helpful for good dimension, but it sometimes is responsible for inferior surface qualities and over cuts. This study suggests a guidance for the optimum finish allowance for machining accuracy improvement, in which the rough cuts are regulated to remain the desired margins without any over cuts. Some experiments were carried out with various cutting conditions including the change of tool strengths and depth of cuts, and also extended to up millings as well as down millings.

The Analysis on Eco-friendly Technologies Effect Applied to SK Chemicals R&D Center (SK케미칼 연구소에 적용된 친환경 기술 적용 효과 분석 - 에너지 및 수자원 절감 적용 효과를 중심으로 -)

  • Yu, Ji-Yong;Lee, Yoo-Ha;Lee, Young-Ryul;Yang, Jae-Woong;Park, Hyun-Geun
    • Proceedings of the SAREK Conference
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    • pp.409-414
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    • 2009
  • The SK Chemical R&D center is an eco-friendly building designed as top score in the GBCC(GREEN BUILDING CERTIFICATE CRITERIA). This building has applied various eco-friendly technologies such as energy /water resource cutdown, improvement of indoor quality and improvement of user convenience, etc through eco-friendly concept from the design phase. In this thesis, an economic efficiency evaluation has been performed on building energy cwater resource cutdown technologies among them and the results are as follows. The building energy has cut down about 40% compared to ordinary buildings and the investment recovery period was shown as about 5 years. The water resource has cut down about 63% compared to ordinary buildings and the investment recovery period was shown as about 10 years.

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A Study for Detecting Fuel-cut Driving of Vehicle Using GPS (GPS를 이용한 차량 연료차단 관성주행의 감지에 관한 연구)

  • Ko, Kwang-Ho
    • Journal of Digital Convergence
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    • v.17 no.11
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    • pp.207-213
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    • 2019
  • The fuel-cut coast-down driving mode is activated when the acceleration pedal is released with transmission gear engaged, and it's a default function for electronic-controlled engine of vehicles. The fuel economy becomes better because fuel injection stops during fuel-cut driving mode. A fuel-cut detection method is suggested in the study and it's based on the speed, acceleration and road gradient data from GPS sensor. It detects fuel-cut driving mode by comparing calculated acceleration and realtime acceleration value. The one is estimated with driving resistance in the condition of fuel-cut driving and the other is from GPS sensor. The detection accuracy is about 80% when the method is verified with road driving data. The result is estimated with 9,600 data set of vehicle speed, acceleration, fuel consumption and road gradient from test driving on the road of 12km during 16 minutes, and the road slope is rather high. It's easy to detect fuel-cut without injector signal obtained by connecting wire. The detection error is from the fact that the variation range of speed, acceleration and road gradient data, used for road resistance force, is larger than the value of fuel consumption data.