• Title/Summary/Keyword: Repairs

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The Compatibility Evaluation of Concrete Repairs under Bending Load (휨하중을 받는 콘크리트 보수재의 적합성기준 평가)

  • 이웅종;정연식;양승규;유재상;이종열
    • Proceedings of the Korea Concrete Institute Conference
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    • 2002.05a
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    • pp.799-804
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    • 2002
  • The compatibility of concrete repairs is proposed by D. Cusson et al. and N. K. Emberson et al. But this is the general compatibility of concrete repairs. This study is actualized the general compatibility of concrete repairs on the flexural specimen under bending load. This study is obtained following results. 1) As a results of analysis for repair effects on failure shape, debonding between concrete and repairs, yielding load and ultimate/yielding ratio, the repair effects is ascertained that the repair R3 is much excellent than the repair R7, but on the other hand R7 is very high than R3 on the viewpoint of compressive strength, where repair R7, R3 is a product. 2) Therefore the compatibility of concrete repair proposed by D. Cusson et al. and N. K. Emberson et al. must be reanalyzed for structures types of column, beam, wall, slab et al.

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Arthroscopic Rotator Cuff Repair by Single Row Technique (회전근 개 파열에 대한 관절경적 봉합술 중 일열 봉합술의 유용성)

  • Yum, Jae-Kwang
    • Clinics in Shoulder and Elbow
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    • v.11 no.2
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    • pp.77-81
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    • 2008
  • The goal of rotator cuff repairs is to achieve high initial fixation strength, minimize gap formation, maintain mechanical stability under cyclic loading and optimize the biology of the tendon-bone interface until the cuff heals biologically to the bone. Single row repairs are least successful in restoring the footprint of the rotator cuff and are most susceptible to gap formation. Double row repairs have an improved load to failure and minimal gap formation. Transosseous equivalent repairs (suture bridge technique) have the highest ultimate load and resistance to shear and rotational forces and the lowest gap formation. Even though the superior advantages of double row and transosseous equivalent repairs, those techniques take longer surgical time and are more expensive than single row repairs. Therefore single row repairs can be useful in bursal side partial thickness or small size full thickess rotator cuff tear.

Preventive Replacement Policy with the Number of General Repairs (일반수리회수에 의한 장비 교환 정책)

  • 김용필;윤덕금
    • Journal of Korean Society for Quality Management
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    • v.28 no.3
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    • pp.11-17
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    • 2000
  • This paper presents a model for determining the optimal number of general repairs and supplementary input cost limit rate in addition to minimal repair cost rate to implement preventive maintenance. The basic concept parallels the periodic replacement model with minimal repair at failure introduced by Barlow and Hunter(1960) and Park(1979), only difference being the replacement signalled by the number of previous general repairs performed on the system. A general repair brings the state of the system to a certain better state than before repaired. Numerical examples are provided.

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Some Stochastic Properties for Imperfect Repair Model

  • Lim, Jae-Hak;Park, Dong-Ho;Sohn, Joong-Kwon
    • Journal of the Korean Statistical Society
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    • v.28 no.3
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    • pp.389-398
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    • 1999
  • We consider an imperfect repair model under which either a perfect repair or a minimal repair can be performed at each failure of a unit. Some stochastic properties of the number of perfect repairs and the number of minimal repairs under the imperfect repair model are investigated. We also derive the expressions for evaluating the expected numbers of perfect and minimal repairs in general and apply these formulas for certain parametric families of life distributions.

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A Repair Process with Embedded Markov Chain

  • Lee, Eui-Yong;Munsup Seoh
    • Journal of the Korean Statistical Society
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    • v.28 no.4
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    • pp.515-522
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    • 1999
  • A repair process of a system consisting of both perfect repairs and minimal repairs is introduced. The type of repair, when the system fails, is determined by an embedded two state Markov chain. We study several stochastic properties of the process including the preservation of ageing properties and the monotonicities of the time between successive repairs. After assigning repair costs to the process, we also show that an optimal repair policy uniquely exists, if the underlying life distribution of the system has DMRL.

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Reliability Analysis for a System under Imperfect Repair Using Fourier Transform Technique (Fourier 변환 기법을 이용한 불완전 수리를 실시하는 시스템의 신뢰도 분석)

  • Kim, Ho Gyun;Son, In Soo
    • Journal of Applied Reliability
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    • v.16 no.2
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    • pp.110-117
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    • 2016
  • Purpose: Biswas and Sarkar [11] found the availability of a system maintained through several imperfect repairs before a replacement is allowed. However they missed a part of coefficients in the integration. This paper corrects the erratum of Biswas and Sarkar [11] and performs the reliability analysis incorporating the optimal number of imperfect repairs. Methods: To find the singularities and residues of the suitable complex-valued function for the availability, the computer package Matlab is used. Also the performance measures are calculated by defining and assigning costs. Results: The accurate availability functions with respect to the numbers of imperfect repairs and the optimal number of imperfect repairs before a replacement are obtained. Conclusion: The reliability for a system under imperfect repair before a replacement is analyzed using Fourier transform technique.

A Study of the Mechanical Properties of Patch-Bonded and Riveted Repairs on Cracked Al 6061-T6 alloy Structures

  • Yoon, Young-Ki;Kim, Guk-Gi;Yoon, Hi-Seak
    • International Journal of Precision Engineering and Manufacturing
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    • v.1 no.2
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    • pp.55-60
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    • 2000
  • A comparison of Riveted and bonded repairs, bearing and net tension failures, and Al 6061-T6 plates is presented. The results are then compared with previous papers about bonded repairs on different patch materials and shapes. Aluminum alloys, including Al 6061-T6, have a face-centered-cubic crystal structure. Under normal circumstances, these types of crystal structures do not exhibit cleavage fractures even at very low temperatures. In aluminum-base structures, the cracked plate structures are frequently repaired using mechanical fasteners-either rivets of bolts- even though patch-bonding techniques are applied to repair and reinforce the structure. Static test results indicate that the riveted repairs are affected by the position of the rivers. When using the same size of patch, the bonded repair technique is stronger; the rate of elongation is also increased. Form FEM analysis, it is revealed the origin of patch debonding in patch-bonded structures is the edge of the patch along to the tensile strength.

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Vascularisation of Urethral Repairs with the Gracilis Muscle Flap

  • Kua, Ee Hsiang Jonah;Leo, Kah Woon;Ong, Yee Siang;Cheng, Christopher;Tan, Bien-Keem
    • Archives of Plastic Surgery
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    • v.40 no.5
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    • pp.584-588
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    • 2013
  • Background The ability to achieve a long-term, stricture-free urethral repair is one of the ongoing challenges of reconstructive urologic surgery. A successful initial repair is critical, as repeat procedures are difficult, owing to distortion, scarring, and short urethral stumps. Methods We describe a technique in which the gracilis muscle flap is laid on or wrapped around the urethral repair site to provide a well-vascularised soft tissue reinforcement for urethral repair. This technique promotes vascular induction, whereby a new blood supply is introduced to the repair site to improve the outcome of urethral repair or anastomotic urethroplasty. The surface contact between the muscle flap and the repair site is enhanced by the use of fibrin glue to improve adherence and promote inosculation and healing. We employed this technique in 4 patients with different urethral defects. Results After a follow-up period of 32 to 108 months, all of the urethral repairs were successful without complications. Conclusions Our results suggest that the use of a gracilis muscle flap to vascularise urethral repairs can improve the outcome of challenging urethral repairs.

The Optimal Limit of the Number of COnsecutive Minimal Repairs

  • Jongho Bae;Lee, Eui-Yong
    • Journal of the Korean Statistical Society
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    • v.30 no.1
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    • pp.89-98
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    • 2001
  • Brown and Proschan(1983) introduced a model for imperfect repair. At each failure of a device, with probability p, it is repaired completely or replaced with a new device(perfect repair), and with probability 1-p, it is returned to the functioning state, but it is only recovered to its condition just prior to failure(imperfect repair or minimal repair). In this paper, we limit the number of consecutive minimal repairs by n. We find some useful properties about $\mu$$_{k}$, the expected time between the k-th and the (k+1)-st repair under he assumption that only minimal repairs are performed. Then, we assign cost to each repair and find the value of n which minimized the long-run average cost for a fixed p under the condition that the life distribution F os the device is DMRL.L.

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