• Title/Summary/Keyword: Under-cut

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A Case Study on Slope Failure by Excessive Under Cut (절토사면 하부의 과도한 굴착에 따른 붕괴 사례 연구)

  • Rhee, Jong-Hyun;Kim, Seung-Hyun;Koo, Ho-Bon
    • Proceedings of the Korean Geotechical Society Conference
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    • 2009.03a
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    • pp.1154-1160
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    • 2009
  • Cut slope failure is happened in various form by several causes. In this study, we searched causes of cut slope failure shortly, and we made a study of slope failure by excessive under cut. Under cutting slope does to add unstability. Thereby, cut slope failure can be happened on a large scale.

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Cut Edge Corrosion of Painted Zn and 55%Al-Zn Coated Steels under Alternate Wetting and Drying

  • Nishikata, A.;Tsuda, T.;Tsuru, T.
    • Corrosion Science and Technology
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    • v.9 no.1
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    • pp.34-38
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    • 2010
  • Electrochemical study on cut edge corrosion of prepainted Zn coated (GI) and 55%Al-Zn coated (GL) steels has been performed in wet-dry cyclic conditions. Maximum width of delaminated polymer coating from the cut edge for GI and GL specimens was evaluated under wet-dry cyclic conditions. The cyclic tests were carried out for 1000 h by changing of relative humidity, where the salt of NaCl was deposited on the specimen every 48 h. The cut edge corrosion test under NaCl deposit indicated that the delamination of the GL specimen progresses at a higher rate than the GI. The electrochemical corrosion monitoring was also performed under condition of alternate exposure to immersion in NaCl solution and drying at 60%RH and $25^{\circ}C$. On the basis of the results of the delamination tests and electrochemical measurements, the mechanism of cut edge corrosion for GI and GL were discussed.

Effects of the Moisture Contents of Cut Tobaccos on Loose End of Cigarettes (각초 수분이 궐련의 끝빠짐에 미치는 영향)

  • Yang Burm-Ho;Jung Han-Ju;Ahn Dae-Jin;Kim Yong-Ok
    • Journal of the Korean Society of Tobacco Science
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    • v.27 no.2
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    • pp.201-206
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    • 2005
  • In this work, we studied the effects of the moisture contents of cut tobacco on loose end of cigarettes. The loose end of the cigarette groups decreased with the increase of moisture contents of the cut tobacco and especially the loose end of A and C groups decreased to $31\%\;and\;52\%$ with the increase of $1\%$ moisture contents. $A-13.5\%\;and\;B-14.0\%\;and\; C-14.0\%$ moisture samples showed the increase of the weight ratio of cut tobacco over 1.4mm cut length but the decrease under 1.4mm cut length. We concluded that the main reasons were regarded to reduction of small fragment tobaccos caused by increase of moisture contents and exception of air-suction transport of tobaccos to cigarette making machine. In spite of the moisture increase of cut tobaccos under fixed EPD(encapsulated pressure drop), the hardness of Band C sample groups were maintained constantly except A group. This result means that under fixed EPD, the weight of cut tobacco in cigarette rods increases to compensate the reduction of pressure drop by moisture increase of cut tobaccos.

The cutting process improvement for cut kimchi cabbage quality (절단배추의 선도유지를 위한 절단 공정 개선)

  • Seong, Gi-Un;Chung, Hun-Sik;Chung, Shin-Kyo
    • Food Science and Preservation
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    • v.22 no.1
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    • pp.154-157
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    • 2015
  • To maintain the freshness and to prevent browning of cut Kimchi cabbages, the effect of the cutting process using a ceramic knife under $N_2$ blowing on the quality of the cut Kimchi cabbages was investigated. Kimchi cabbages cut with a ceramic knife under $N_2$ gas blowing conditions (NC) were stored at $5^{\circ}C$ for 7 days, and their weight reduction ratio and the browning degree and appearance were compared with those of the control treatment samples (OS; cut with a stainless steel knife under normal air, OC; cut with a ceramic knife under normal air). The weight reduction ratios were 0.07~0.13%, and the NC treatment showed the lowest reduction ratio among all the treatments (p<0.05). The Hunter L values increased, but the a and b values decreased after 5-day storage in all the treatments. The NC treatment had higher L values but lower a and b values than the OS and OC treatments. The browning degrees by Hunter color value, PPO activity, and appearances were the least in the NC treatment (p<0.05). The cutting process with a ceramic knife under $N_2$ blowing could be applied to the cutting of vegetable products and for minimal fruit processing.

On the maintenance of Semimanufactured Tobacco(cut tobacco) quality during Shipping or Long Term Straging (수송 또는 보관중 반제품(각초) 담배의 품질유지에 관하여)

  • 민영근;정한주;김기환;양광규
    • Journal of the Korean Society of Tobacco Science
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    • v.14 no.1
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    • pp.57-65
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    • 1992
  • The quality of cut tobacco will be deteriorated due to weather conditions such as temperature and relative humidity, when shipping and long term storaging. The change of equilibrium moisture contents in cut tobacco were under influence of relative humidity and temperature but not humectants. Therefore internal packing materials are necessary for cut tobacco to maintain initial quality, including taste, flavour and musty smell during shipping or storaging. When packing cut tobacco for shipping or long term storaging, desiralbe packing density was 200/$m^2$, For the long term storage under R.H 90% and 3$0^{\circ}C$, polyethylene film thickness suitable for packing material are above 100$\mu$, which resulted in 42days of shelf life.

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A Study on the Stability Evaluation of Railway Cut-Slope Under Rainfall (강우시 철도 절개사면의 안정성 평가에 관한 연구)

  • 김현기;박영곤;신민호
    • Proceedings of the Korean Geotechical Society Conference
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    • 2001.03a
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    • pp.273-280
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    • 2001
  • In order to evaluate the stability of railway cut-slope under rainfall, explanatory variables and subordinate variables were selected for multivariate analysis. Furthermore the site which had occurred failure due to rainfall was investigated, and by executing multivariate analysis for 121 cases, critical rainfall was defined by the case that had high value of correlation factor. The 0.3 square value of maximum hourly rainfall during 24 hours before failure caused the collapse of railway cut-slope and could be used to estimate the stability of railway cut-slope. From the result of application to a collapse example, the evaluaton method by critical rainfall curve is satisfactory.

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Temperature Effect on Tensile Strength of Filled Natural Rubber Vulcanizates (가황 천연고무의 인장강도에 미치는 온도의 영향)

  • Ko, Young-Chon;Park, Byung-Ho
    • Elastomers and Composites
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    • v.36 no.4
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    • pp.255-261
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    • 2001
  • This study was related with the effect of elevated temperature on the tensile strength of edge-cut samples. There was a different tensile strength behavior of uncut samples and pre-cut samples under different test temperatures. Tensile strength of uncut sample decreases with increasing test temperature. When pro-cut size(C) is larger than critical cut size($C_{cr}$), tensile strength or pre-cut specimen at $80^{\circ}C$ is higher than that of pre-cut specimen at room temperature (RT). Test specimens under $80^{\circ}C$ condition exhibited more secondary cracks at the crack tip region compared to room temperature conditions. However, secondary cracks of pre-cut specimens are not clearly developed at $110^{\circ}C$. Differences in tensile strength induced by different test temperature seem to be responsible for the strain-induced crystallization and micro-cracking patterns.

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Development of miniature bar-type structural fuses with cold formed bolted connections

  • Guan, Dongzhi;Yang, Sen;Jia, Liang-Jiu;Guo, Zhengxing
    • Steel and Composite Structures
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    • v.34 no.1
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    • pp.53-73
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    • 2020
  • A novel all-steel miniature bar-type structural fuse (MBSF) with cold formed bolted connections is developed in this study, which consists of a central energy dissipation core cut from a smooth round bar, an external confining tube and nuts. Three types of cross sections for the central energy dissipation core, i.e., triple-cut, double-cut and single-cut cross sections, were studied. Totally 18 specimens were axially tested under either symmetric or asymmetric cyclic loading histories, where the parameters such as cut cross sectional area ratio, length of the yielding portion and cross sectional type were investigated. Numerical simulation of 2 representative specimens were also conducted. An analytical model to evaluate the bending failure at the elastic portion was proposed, and a design method to avoid this failure mode was also presented. The experimental results show that the proposed MBSFs exhibit satisfactory hysteretic performance under both the two cyclic loading histories. Average strain values of 8% and 4% are found to be respectively suitable for designing the new MBSFs as the ultimate strain under the symmetric and asymmetric cyclic loadings.

A Weight-reduction Design Method by Underframe Material Substitution in a Box-type Bodyshell with Cut-outs (Cut-out이 있는 Box형 차체의 하부구조 소재대체 경량화 설계 방법)

  • Cho, Jeonggil;Koo, Jeongseo;Jung, Hyunseung
    • Transactions of the Korean Society of Automotive Engineers
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    • v.21 no.2
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    • pp.45-54
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    • 2013
  • In this paper, a theoretical weight-reduction method was suggested to substitute an underframe material of a box-type bodyshell having cut-outs with an alternative light-weight material. To utilize the material substitution method previously developed for a box-type hybrid bodyshell not having cut-outs, we derived a box-type baseline model without cut-outs which is similar to the stiffness condition of a box-type bodyshell having cut-outs. To do this, the thicknesses of roof and walls of the baseline model were determined such that the deflection of the baseline model under a distributed vertical load condition is equal to the sum of the theoretical section deflections of the original box model with cut-outs. Next, to derive a hybrid bodyshell by under-frame material substitution, the material substitution method for a box-type hybrid bodyshell without cut-outs was applied to the box-type baseline model. Finally, we compared the FE simulation results of the derived hybrid bodyshells having cut-outs for various materials with the theoretical results of the suggested method, and we obtained their good correlations.

Dynamic stability evaluation of nail stabilised vertical cuts in various site classes

  • Amrita;B.R. Jayalekshmi;R. Shivashankar
    • Geomechanics and Engineering
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    • v.38 no.4
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    • pp.421-437
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    • 2024
  • The soil nailing method entails the utilisation of nails to reinforce and stabilise a zone of soil mass. This is widely used for various applications due to its effective performance under various loading conditions. The seismic response of 6m high vertical soil-nailed cut in various site classes under dynamic excitations has been investigated in this study considering various lengths and inclinations of nails. The influence of frequency content of dynamic excitation on the response of structure has been assessed through finite element analysis using time history data of three different earthquakes. The seismic stability of the nailed cut in retaining soil in various sites under El Centro, Kobe and Trinidad earthquake ground motion is evaluated based on maximum acceleration response, maximum horizontal deformation, earth pressure distribution on the wall and maximum axial force mobilised in nails. The optimum nail inclination is identified as 15° and a minimum nail length ratio of 0.7 is essential for a stable vertical cut under dynamic excitations.