• Title/Summary/Keyword: Active failure

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Stability analysis of a rock slope in Himalayas

  • Latha, Gali Madhavi;Garaga, Arunakumari
    • Geomechanics and Engineering
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    • v.2 no.2
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    • pp.125-140
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    • 2010
  • Slope stability analysis of the right abutment of a railway bridge proposed at about 350 m above the ground level, crossing a river and connecting two huge hillocks in the Himalayas, India is presented in this paper. The site is located in a highly active seismic zone. The rock slopes are intensely jointed and the joint spacing and orientation are varying at different locations. Static slope stability of the rock slope is studied using equivalent continuum approach through the most commonly used commercial numerical tools like FLAC and SLOPE/W of GEOSTUDIO. The factor of safety for the slope under static conditions was 1.88 and it was reduced by 46% with the application of earthquake loads in pseudo-static analysis. The results obtained from the slope stability analyses confirmed the global stability of the slope. However, it is very likely that there could be possibility of wedge failures at some of the pier locations. This paper also presents the results from kinematics of right abutment slope for the wedge failure analysis based on stereographic projections. Based on the kinematics, it is recommended to flatten the slope from 50o to 43o to avoid wedge failures at all pier locations.

Factors Associated With Success or Failure of Quit Attempts: A Clinical Approach for Lung Cancer Prevention

  • Su, Tin Tin;Sallehuddin, Bin Abu Bakar;Murniati, Hj Hussain;Swinder, Jit;Sadat, Nabilla Al;Saimy, Ismail
    • Asian Pacific Journal of Cancer Prevention
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    • v.13 no.1
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    • pp.175-179
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    • 2012
  • The objective of the study is to investigate the success rate of quit attempts and identify factors associated with success or failure of quit attempts in a quit smoking clinic. A cohort study was conducted with 495 smokers who enrolled in a quit smoking clinic from 2005 to 2008. The factors leading to quit smoking successfully were "being Malay", "having high blood pressure" "type of Nicotine Replacement Therapy" and "duration of follow up". In contrast, clerical staff had negative association to quit smoking. People who started smoking in their teenage years had a high risk of relapse. Integration of active follow up and tailor-made support programmes for quitters appear necessary in order to maintain their non-smoking status and encourage them to be permanent quitters. Integration of quit smoking clinics and primary care clinics could be another potential step for the success of quit smoking programmes.

Linear regression analysis for factors influencing displacement of high-filled embankment slopes

  • Zhang, Guangcheng;Tan, Jiansong;Zhang, Lu;Xiang, Yong
    • Geomechanics and Engineering
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    • v.8 no.4
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    • pp.511-521
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    • 2015
  • It is a common failure type that high-filled embankment slope sideslips. The deformation mechanism and factors influencing the sideslip of embankment slope is the key to reduce the probability of this kind of engineering disaster. Taking Liujiawan high-filled embankment slope as an example, the deformation and failure characteristics of embankment slope and sheet-pile wall are studied, and the factors influencing instability are analyzed, then the correlation of deformation rate of the anti-slide plies and each factor is calculated with multivariate linear regression analysis. The result shows that: (1) The length of anchoring segment is not long enough, and displacement direction of embankment and retaining structure are perpendicular to the trend of the highway; (2) The length of the cantilever segment is so large that the active earth pressures behind the piles are very large. Additionally, the surface drainage is not smooth, which leads to form a potential sliding zone between bottom of the backfill and the primary surface; (3) The thickness of the backfill and the length of the anti-slide pile cantilever segment have positive correlation with the deformation whereas the thickness of anti-slide pile through mudstone has a negative correlation with the deformation. On the other hand the surface water is a little disadvantage on the embankment stability.

Study of Corrosion-Induced Failure Mechanisms of Epoxy Coated Reinforcing Steel (Parts I and II)

  • Lee, Seung-kyoung
    • Proceedings of the Korea Concrete Institute Conference
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    • 1995.04a
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    • pp.396-401
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    • 1995
  • Epoxy coated reinforcing steels (ECRs) were acquired from ten sources and coatings from each source were initially characterized in terms of defects, thickness, solvent extraction weight loss and hardness. Testing involved exposure in three aqueous solutions at elevated temperature (8$0^{\circ}C$) and in chloride-contaminated concrete slabs under outdoor exposure, It was found that the density and size of coating defects was the promary factor affecting ECR performance. The equivalent circuit analysis using electrochemical impedance spectroscopy (EIS) data indicated that the impedance response for well-performing ECR specimens showed no signs of active degradation at the interface although diffusional processes similar to those noted for poorly performing bars occurred here. Experimental results also indicated a relationship between corrosion behavior and bar source. Weight loss upon solvent extraction correlated with impedance reduction from hot water exposure. Coating defects during most of the tests, especially in high pH solutions containing chloride ions. ECRs with excessive coating defects, either initially present or ones which developed in service, performed poorly in every test category regardless of source. Forms of coating failure were extensive rusting at defects, blistering, wet adhesion loss, cathodic delamination, underfilm corrosion and coating cracks. These occurred sequentially or concurrently, depending on the condition of the ECR and nature of the environment

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Dynamic Island Partition for Distribution System with Renewable Energy to Decrease Customer Interruption Cost

  • Zhu, Junpeng;Gu, Wei;Jiang, Ping;Song, Shan;Liu, Haitao;Liang, Huishi;Wu, Ming
    • Journal of Electrical Engineering and Technology
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    • v.12 no.6
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    • pp.2146-2156
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    • 2017
  • When a failure occurs in active distribution system, it will be isolated through the action of circuit breakers and sectionalizing switches. As a result, the network might be divided into several connected components, in which distributed generations could supply power for customers. Aimed at decreasing customer interruption cost, this paper proposes a theoretically optimal island partition model for such connected components, and a simplified but more practical model is also derived. The model aims to calculate a dynamic island partition schedule during the failure recovery time period, instead of a static islanding status. Fluctuation and stochastic characteristics of the renewable distributed generations and loads are considered, and the interruption cost functions of the loads are fitted. To solve the optimization model, a heuristic search algorithm based on the hill climbing method is proposed. The effectiveness of the proposed model and algorithm is evaluated by comparing with an existing static island partitioning model and intelligent algorithms, respectively.

Sphingosine 1-Phosphate Receptor Modulators and Drug Discovery

  • Park, Soo-Jin;Im, Dong-Soon
    • Biomolecules & Therapeutics
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    • v.25 no.1
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    • pp.80-90
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    • 2017
  • Initial discovery on sphingosine 1-phosphate (S1P) as an intracellular second messenger was faced unexpectedly with roles of S1P as a first messenger, which subsequently resulted in cloning of its G protein-coupled receptors, $S1P_{1-5}$. The molecular identification of S1P receptors opened up a new avenue for pathophysiological research on this lipid mediator. Cellular and molecular in vitro studies and in vivo studies on gene deficient mice have elucidated cellular signaling pathways and the pathophysiological meanings of S1P receptors. Another unexpected finding that fingolimod (FTY720) modulates S1P receptors accelerated drug discovery in this field. Fingolimod was approved as a first-in-class, orally active drug for relapsing multiple sclerosis in 2010, and its applications in other disease conditions are currently under clinical trials. In addition, more selective S1P receptor modulators with better pharmacokinetic profiles and fewer side effects are under development. Some of them are being clinically tested in the contexts of multiple sclerosis and other autoimmune and inflammatory disorders, such as, psoriasis, Crohn's disease, ulcerative colitis, polymyositis, dermatomyositis, liver failure, renal failure, acute stroke, and transplant rejection. In this review, the authors discuss the state of the art regarding the status of drug discovery efforts targeting S1P receptors and place emphasis on potential clinical applications.

A study on the Average Factor of Safety in Slope Stability Being Applied to Wedge theory (Wedge 이론을 적용한 사면안정해석의 평균 안전율에 관한 연구)

  • 김경진
    • Journal of the Korean Professional Engineers Association
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    • v.19 no.1
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    • pp.3-11
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    • 1986
  • The analysis of Geotechnical stability problems by the limit equilibrium method involve assuming the shape of the failure and then investigating many surfaces of the shape to identify the one on which failure seems most likely to occur. These arbitrary assumptions most frequently concern to the locations or directions of side force on slice and the overall factor of safety is considered identical to the local factor of safety. In this paper, let the factor of safety of a slope at wedge block stage differently, when an upper part of the potential sliding mass has a simple active stress field and the lower part of the passive stress field and overall factor of safety is obtained by the average of local factor and computer program based on the modified wedge Method is proposed for this thesis. The new algorithm based on tile modified new method is made for estimating the safety factor of Earth Dam. Compared with conventional method for many cases tile average values of the factor of safety determined by the modified new method are very nearly the same. For all of the cases studied the difference was found 0.03. Finally this new method is thought to be very useful in slope stability analysis.

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An Intervention Study on the Implementation of Control Banding in Controlling Exposure to Hazardous Chemicals in Small and Medium-sized Enterprises

  • Terwoert, Jeroen;Verbist, Koen;Heussen, Henri
    • Safety and Health at Work
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    • v.7 no.3
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    • pp.185-193
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    • 2016
  • Background: Management and workers in small and medium-sized enterprises (SMEs) often find it hard to comprehend the requirements related to controlling risks due to exposure to substances. An intervention study was set up in order to support 45 SMEs in improving the management of the risks of occupational exposure to chemicals, and in using the control banding tool and exposure model Stoffenmanager in this process. Methods: A 2-year intervention study was carried out, in which a mix of individual and collective training and support was offered, and baseline and effect measurements were carried out by means of structured interviews, in order to measure progress made. A seven-phase implementation evolutionary ladder was used for this purpose. Success and failure factors were identified by means of company visits and structured interviews. Results: Most companies clearly moved upwards on the implementation evolutionary ladder; 76% of the companies by at least one phase, and 62% by at least two phases. Success and failure factors were described. Conclusion: Active training and coaching helped the participating companies to improve their chemical risk management, and to avoid making mistakes when using and applying Stoffenmanager. The use of validated tools embedded in a community platform appears to support companies to organize and structure their chemical risk management in a business-wise manner, but much depends upon motivated occupational health and safety (OHS) professionals, management support, and willingness to invest time and means.

Design and Implementation of a Fault-Tolerant Magnetic Bearing System

  • Park, B.C.;Noh, M.D.;Ro, S.K.;Kyung, J.H.;Park, J.K.
    • KSTLE International Journal
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    • v.4 no.2
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    • pp.37-42
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    • 2003
  • One of the obstacles for a magnetic bearing to be used in the wide range of industrial applications is the failure modes associated with magnetic bearings, which we don't expect for conventional passive bearings. These failure modes include electric power outage, power amplifier faults, position sensor faults, and the malfunction of controllers. Fault-tolerant magnetic bearing systems have been proposed so that the system can operate in spite of some faults in the system. In this paper, we designed a fault-tolerant magnetic bearing system for a turbo-molecular vacuum pump. The system can cope with the actuator/amplifier faults which are the most common faults in a magnetic bearing system. We implemented the existing fault-tolerant algorithms to experimentally prove the adequacy of the algorithms for industrial applications. As it turns out, the system can operate even with three simultaneously failing poles out of eight actuator poles.

The bibliographical study on the cause and originative of vertigo (현운(眩暈)의 원인(原因)과 기전(機轉)에 대(對)한 문헌적(文獻的) 고찰(考察))

  • Kim, Kang-San
    • The Journal of Internal Korean Medicine
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    • v.13 no.1
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    • pp.167-180
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    • 1992
  • This study has been carried out to investigate the cause and originative mechanism of vertigo by referring to 46 literatures. The results were as follows; 1. The 1st factors causing vertigo are exuberance of fire in the Liver (肝火偏亢). and ascending of Yang of Wind (風陽升動) resulting from thought excess (思慮太過) and melancholy (憂鬱). 2. The 2nd factors causing vertigo is a malnurtrient of the brain resulting from dispersion of the Liver function (肝血虛) and failure in ascending of the Clear Yang (淸陽不升) due to hemorrhage and so on. 3. The 3rd factors causing vertigo are failure in ascending to the Brain and deficiency of blood of the Liver (肝血虛) resulting from the injury of the essence of the Kidney (肝精虧損). 4. The 4th factors causing vertigo is a ascending of exogenous pathogenic factors (外邪) to the Brain on deficiency state. 5. The 1st factors causing vertigo are Stagnatum of clear Yang (淸陽不振) and pershing of Yang (亡陽) resulting from loss of water and damage of active thin body fluid (津氣虧損). 6. The obesity is beonged to excessiveness Symptom-Complex (實證) and the thin to deficiency Symptom-complex (虛證). 7. The vertigo is connective with the Live (肝), Spleen (脾) and the Kidney (腎), but among those, most intimative viscera is the Liver (肝).

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