• Title/Summary/Keyword: surface inclination

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Evaluating the effects of the inclinations of rock blocks on the stability of bimrock slopes

  • Khorasani, Emad;Amini, Mehdi;Hossaini, Mohammad Farouq;Medley, Edmund
    • Geomechanics and Engineering
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    • v.17 no.3
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    • pp.279-285
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    • 2019
  • The process of slope stability analysis is one of the most important stages in design of some civil and mining projects. Bimslopes are made from bimrocks (block-in-matrix rocks) where rocky blocks are distributed in a bonded matrix of finer texture. These kind of slopes are often seen in weathered and near-surface depths. Previous studies have shown that VBP (Volumetric Block Proportion) is one of the most significant factors affecting bimrocks strength and consequently the stability of bimslopes. In this paper, the influence of block inclinations on bimslope stability have been investigated. For this purpose, 180 theoretical models have been made with various VBPs, all of them have a specified block size distribution. These bimslopes contain blocks with differing dips relative the slope inclination. Also for each kind of block inclination, 10 different blocks arrangements have been modeled. The Finite Element Method (FEM) was used to analysis the stability of these bimslopes models. The results showed the inclination of blocks has a strong impact on the Safety Factor and stability of bimslopes. When the difference in angle of dip of blocks relative to the slope angle is maximum, the Safety Factor of bimslopes tends to be a maximum compared with the matrix-only state. Furthermore, with increasing VBP of bimslopes stability increases. The graphs obtained from this study could be used for preliminary guidance in the projects design with bimslopes.

The Cutting Characteristics of Rotary Tools Using Regression Analysis (회귀분석법을 이용한 로타리 공구의 절삭 특성)

  • 심승천;장성민;맹민재;정준기
    • Proceedings of the Korean Society of Machine Tool Engineers Conference
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    • 2004.04a
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    • pp.105-110
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    • 2004
  • This paper deals with the study of feasibility of rotary carbide tools in the machining of aluminium alloy. A rotary tool holder was designed and manufactured for this work. Experiments were performed using Taguchi methods and regression analysis to analyse the influence of various factors and their interactions on the cutting characteristics of rotary carbide tools during machining. The cutting force is influenced the most featly at the inclination angle. The surface roughness is influenced distinctly at depth of cut. It deduced an equation to predict cutting force and surface roughness. Hence, it could be concluded here that the proposed model agrees with the experimental data satisfactorily.

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Analysis of Maximum Solar Radiation on Inclined Surfaces in Korea (국내 최대 경사면일사량 분석)

  • Jo, Dok-Ki;Yun, Chang-Yeol;Kim, Kwang-Deuk;Kang, Young-Heack
    • 한국태양에너지학회:학술대회논문집
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    • 2009.04a
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    • pp.3-7
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    • 2009
  • The amount of incident rays over inclination according to direction has been widely utilized as important data in installing solar thermal systems. To optimize the incident solar radiation, the slope, that is the angle between the plane surface in question and the horizontal, and the solar azimuth angles are needed for these solar thermal systems. This is because the performance of the solar thermal systems in much affected by angle and direction of incident rays. Recognizing that factors mentioned above are of importance, actual experiment on the moving route of the sun have been performed in this research to obtain the angle of inclination with which the maximum incident rays can be absorbed. After all, the standard for designing highly optimized solar thermal systems will be provided for designers and employees working in the solar collector related industries.

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A method of contouring occlusal surface for reduction of implant overload (Implant overload 감소를 위한 교합면 형성 방법)

  • Lee, Byung-Woo;Park, Chan-Jin;Cho, Lee-Ra;Yi, Yang-Jin
    • Journal of Dental Rehabilitation and Applied Science
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    • v.19 no.2
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    • pp.105-108
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    • 2003
  • After stage-two surgery, the highest incidence of failure has been attributed to implant overload. However, the biomechanical factors cited inthe literature that contribute to implant overload, such as bone type, cuspal inclination, horizontal offset, maxillary compared to mandibular arch, the inclusion of natural teeth within the prosthesis, and occlusal harmony are superimposed on physiologic variations. Following two cases, including reduction of cuspal inclination and usage of modified incisal pin, showed a method of contouring occlusal surface for reduction of unpreditable implant overload.

The Cutting Characteristics of Rotary Tools Using Regression Analysis (회귀분석법을 이용한 로타리 공구의 절삭 특성)

  • Maeng, Min-Jae;Jang, Sung-Min
    • Journal of the Korean Society of Manufacturing Process Engineers
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    • v.4 no.4
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    • pp.14-20
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    • 2005
  • This paper deals with the study of feasibility of rotary carbide tools in the machining of aluminium alloy. A rotary tool holder was designed and manufactured for this work. Experiments were performed using Taguchi methods and regression analysis to analyse the influence of various factors and their interactions on the cutting characteristics of rotary carbide tools during machining. The cutting force is influenced the most greatly at the inclination angle. The surface roughness is influenced distinctly at depth of cut. It deduced an equation to predict cutting force and surface roughness. Hence, it could be concluded here that the proposed model agrees with the experimental data satisfactorily.

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A Study on the Spray Cooling Characteristics on the Angle of Hot Heat Transfer Surface (고온 열전달면의 각도에 따른 분무냉각특성에 관한 연구)

  • Yoon, D.H.;Kim, K.K.;Kim, M.H.;Oh, C.;Yoon, S.H.
    • Proceedings of the Korean Society of Marine Engineers Conference
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    • 2001.11a
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    • pp.8-14
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    • 2001
  • The purpose of this study is to elucidate heat characteristics according to inclination angle of the hot flat plate at the spray cooling. As results of this experiment, the heat flux, the heat transfer coefficient and the cooling speed are increased as the liquid volume flux and subcooled temperature go up. And as the inclination angle of the heat transfer surface is increased, the cooling speed on the inclined flat plate becomes faster. It means that the cooling ability is increased because droplets were excluded by gravity.

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THE STUDIES ON THE ERUPTION PATTERN OF FIRST PERMANENT MOLARS (제1대구치(第一大臼齒)의 맹출양장(萌出樣狀)에 관(關)한 연구(硏究))

  • Shon, Dong-Su
    • Journal of the korean academy of Pediatric Dentistry
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    • v.3 no.1
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    • pp.7-11
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    • 1976
  • The author measured the degree of development and the eruption pattern of first permanent molars with orthopantomography in 553 Korean children(male; 302, female; 251) from 4 to 9 years old. The orthopantomographs were obtained from dept. of pedodontics, college of dentistry, Seoul National University. The results of the studies were as follows: 1. Upper first permanent molars were erupted with distal inclination of about 30 degrees in the early stage and they gradually moved in the mesial direction by bodily movement of the tooth to be in contact with the disto-proximal surface of primary secondary molars in the late stage. 2. Lower first permanent molars were erupted with mesial inclination in the early stage and moved mesially by tipping movement of the tooth to be in contact with the disto proximal surface of the second primary molars in the late stage. 3. The eruptive forces were considered to be main etiologic factors of space closure after the premature loss of primary molars.

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Analysis of Maximum Solar Radiation on Inclined Surfaces for the Installation of Solar Thermal Systems in Korea Using the Optimum Installation Angle (국내 태양열시스템 설치를 위한 시스템 최적 설치각 산출을 통한 최대 경사면일사량 분석)

  • Jo, Dok-Ki;Kang, Young-Heack
    • Journal of the Korean Solar Energy Society
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    • v.29 no.2
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    • pp.47-54
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    • 2009
  • The amount of incident rays over inclination according to direction has been widely utilized as important data m installing solar thermal systems. To optimize the incident solar radiation, the slope, that is the angle between the plane surface in question and the horizontal, and the solar azimuth angles are needed for these solar thermal systems. This is because the performance of the solar thermal systems in much affected by angle and direction of incident rays. Recognizing that factors mentioned above are of importance, actual experiment on the moving route of the sun have been performed in this research to obtain the angle of inclination with which the maximum incident rays can be absorbed. After all, the standard for designing highly optimized solar thermal systems will be provided for designers and employees working in the solar collector related industries.

The Hydrodynamic Stability of Natural Convection Flows Adjacent to an Inclined Isothermal Surface Submerged in Cold, Pure Water (순수한 찬물속에 잠겨있는 경사진 등온벽면 부근의 자연대류에 관한 수동력학적 안정성)

  • Hwang, Y.K.;Jang, M.R.
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.2 no.4
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    • pp.268-278
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    • 1990
  • Hydrodynamic stability equations are formulated for natural convection flows adjacent to a heated or cooled, inclined, isothermal surface in pure water at $4^{\circ}C$, where the density variation with temperature becomes nonlinear. The resulting stability equations, when reduced to ordinary differential equations by a similarity transformation, constitute a two-point boundary-value problem, which was solved numerically. It is found from the obtained stability results that the neutral stability curves are systematically shifted to have lower critical Grashof numbers, as the inclination angle of upward-facing plate increases. Also, the nose of the neutral stability curve becomes blunter as the angle increases. It implies that the greater the inclination of the upward-facing plate, the more susceptible of the flow to instability for the wide range of disturbance wave number and frequency.

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Experimental and numerical analysis of mixed mode I/III fracture of sandstone using three-point bending specimens

  • Li, Yifan;Dong, Shiming;Pavier, Martyn J.
    • Structural Engineering and Mechanics
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    • v.76 no.6
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    • pp.725-736
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    • 2020
  • In this work the mixed mode I/III fracture of sandstone has been studied experimentally and numerically. The experimental work used three-point bending specimens containing pre-existing cracks, machined at various inclination angles so as to achieve varying proportions of mode I to mode III loading. Dimensionless stress intensity factors were calculated using the extended finite element method (XFEM) for and compared with existing results from literature calculated using conventional finite element method. A total of 28 samples were used to conduct the fracture test with 4 specimens for each of 7 different inclination angles. The fracture load and the geometry of the fracture surface were obtained for different mode mixities. Prediction of the fracture loads and the geometry of the fracture surface were made using XFEM coupled with a cohesive zone model (CZM) and showed a good comparison with the experimental results.