• Transactions of the Korean Society of Mechanical Engineers A
• /
• v.37 no.5
• /
• pp.649-655
• /
• 2013

During welding, the dissimilar metal butt welds of nuclear piping are typically subjected to repair welding in order to eliminate defects that are found during post-weld inspection. It has been found that the repair weld can significantly increase the tensile residual stress in the weldment, and therefore, accurate estimation of the weld residual stress due to repair weld, especially for dissimilar metal welds using Ni-based alloy 82/182 in nuclear components, is of great importance in order to assess susceptibility to primary water stress corrosion cracking. In the present study, the stress distributions of dissimilar metal butt welds in nuclear reactor piping subjected to repair weld were investigated based on detailed nonlinear finite element analyses. Particular emphasis was placed on the variation of the stress distribution in the dissimilar metal butt weld according to the finite element welding analysis sequence for the repair welding process.

• Journal of Chest Surgery
• /
• v.54 no.3
• /
• pp.186-190
• /
• 2021

Background: Pre-lifting of the sternum marked a major turning point in pectus excavatum repair. The author developed the crane technique in 2002 and successfully applied it to more than 2,000 cases using sternal wire stitching. However, blind sternal suturing limited the use of the wire-stitch crane. We propose a novel screw for sternal lifting as a new tool for the crane technique. Methods: We developed a screw system strong enough to withstand the pressure needed for sternum lifting. The screw was designed to have a broader thread to hold the bony tissue securely. The screw's sustaining power was tested using the torsion, driving torque, and axial pull-out tests in a polyurethane block and ex-vivo porcine sternum. Results: The screws were easily driven into the sternum, and the head of the screw was connectable to the table-mounted retractor. In the torsion test, the 2° offset torsional yield was 4.53 N·m (reference value, 1 N·m). In the polyurethane block driving torque test, the maximum torque was 0.98 N·m (reference value, 0.70 N·m). The axial pull-out test was 446 N (reference value, 100 N). The maximum pull-out resistance in the ex-vivo porcine sternum model was 1,516 N. Conclusion: The screw crane was strong enough to sustain the chest wall weight to be lifted. Thus, the screws could effectively replace the sternal wire stitching in crane pre-lifting of the sternum. We expect that application of the screw-crane will be easy and that it will improve the safety and success rate of pectus repair surgery.

• Journal of the Korean Arthroscopy Society
• /
• v.10 no.1
• /
• pp.83-86
• /
• 2006

Purpose: We repoted the clinical results and introduction of surgical techniques for the patients with tears of the triangular fibrocartilage complex (TFCC) who had arthroscopic management. Materials and Methods: According to Palmer classification, nine patients(9 wrists) with type 1B lesions of the triangular fibrocartilage complex from 2001 to 2004 were included in this study. The mean follow-up period was 28 months. Six were male and three were female, right side was in seven cases and left side in two cases. Nine patients received arthroscopic debridement and repair by outside-in technique. To assess the clinical outcomes, the visual analogue pain scale(VAPS), grip strength, range of motion were investigated. Results: The average of VAPS improved from 6.2 to 1.4. The grip strength of wrists of all nine patients improved after surgery and the range of motion of all wrists reached full range. Conclusion: Arthroscopic repair of type 1B tear of the triangular fibrocartilage complex has satisfactory results. The repair by outside-in technique was simple and we could have secure fixation.

• Journal of the Korean Arthroscopy Society
• /
• v.9 no.1
• /
• pp.40-45
• /
• 2005

Purpose: This study is to evaluate the clinical findings of media] meniscus root tear, pull-out repair technique and it's short term results. Materials and Methods: From September 2003 to August 2004, 23 cases of total 27 medial meniscus root tears were treated by pull-out repair technique. Mean age was 60.2 years old. The pull-out technique was divided into 2 groups In group 1(14/23 cases), anterolateral portal was used and in group 2(9/23 cases), anterolateral and posteromedial portals were used for bed preparation. Concomitant cartilage lesions were documented as ICRS mapping system. The clinical outcomes were evaluated according to Lysholm Knee Score. Results: The postoperative Lysholm Knee Score was 77.1(range; $58{\sim}97$) in group 1 and 81.4(range; $72{\sim}94$) (p>0.05). The failure rate was 3 of 14 cases(21.4%) in group 1 and 1 of 9 cases(11.1%) in group 2. Twenty of 22 cases(90.9%) showed cartilage lesions in weight bearing portion of medial femoral condyle which were 8 grade III and 5 grade IV according to the Outerbridge classification. Conclusion: Pull-out repair seems to be a useful treatment of the medial meniscus root tear for preservation of circumferential hoop tension of meniscus.

• International Journal of Quality Innovation
• /
• v.5 no.1
• /
• pp.1-9
• /
• 2004

The nonhomogeneous poisson process (NHPP) is often used to model repairable systems that are subject to a minimal repair strategy, with negligible repair times. In this situation, the system can be characterized by its intensity function. There have been many NHPP models according to intensity functions. However, the intensity function of system in use can be changed because of repair or its aging. We consider the single change point model as the modification of the power law process. The shape parameter of its intensity function is changed before and after the change point. We detect the presence of the change point using Bayesian methodology. Some numerical results are also presented.

• Journal of the Korean Operations Research and Management Science Society
• /
• v.25 no.4
• /
• pp.27-44
• /
• 2000

In this study we consider a spares provisioning problem for repairable items in which a parts inventory system is incorporated. If a machine fails, a replacement part must be obtained at the parts inventory system before the failed machine enters the repair center. The inventory policy adopted at the parts inventory system is the (S, Q) policy. Operating times of the machine before failure, ordering lead times and repair times are assumed to follow a two-stage Coxian distribution. For this system, we develop an approximation method to obtain the performance measures such as steady state probabilities of the number of machines at each station and the probability that a part will wait at the parts inventory system. For the analysis of the proposed system, we model the system as a closed queueing network and analyze it using a product-form approximation method. A recursive technique as well as an iterative procedure is used to analyze the sub-network. Numerical tests show that the approximation method provides fairly good estimation of the performance measures of interest.

• Proceedings of the KSR Conference
• /
• 2004.06a
• /
• pp.159-164
• /
• 2004

Recently the unexpected damage is broken out by the unusal change of weather. Misfortune on top of misfortune the typhoon did great damage again before finishing the repair work. And then we should study about the repair work of fast and safety as well as the construction of safety. The paper suggests the case study of a fast disaster restoration work. To minimise the term of repair work which selects Fast Track Method. This work is processed as follows. Temporary resortation is progressed at the same time as the main resortation. And In this paper, technique to evaluate the capacity of bridge is tried to develop by means of FEM analysis.

• Earthquakes and Structures
• /
• v.15 no.2
• /
• pp.165-178
• /
• 2018

The aim of this study is to investigate the efficiency of using threaded rods and steel profiles to produce a steel confining system for rehabilitation of damaged concrete corbels for the first time in literature. Some of the specimens were repaired by crack repair epoxy before being confined for further enhancement. A total of 19 two sided damaged corbels were used in the study with different mechanical properties and parameters but similar dimensions. The differences were in rehabilitation style, shear span, fiber percentage, reinforcement steel diameter, and concrete strength. The rehabilitated specimens were loaded with vertical load until failure. Four different configurations were used in the investigation. Test results show that the proposed rehabilitation technique is effective to enhance the load capacity of the corbels and to improve their ductility. Moreover, new formulations were proposed to calculate the load capacity of the rehabilitated corbels. A good fit was observed between numerical and experimental results.

• Journal of Chest Surgery
• /
• v.21 no.2
• /
• pp.326-333
• /
• 1988

The results of surgical experience of double outlet right ventricle with pulmonic stenosis in 14 patients are reported. Among the 14 patients, 8 underwent the intraventricular tunnel repair with the result of 3 hospital deaths, 5 had Fontan type operations due to the various anatomic reasons and resulted in one hospital death, and the remaining one patient had palliative pulmonary valvotomy. Besides the problems related to the effective relief of the pulmonic stenosis, double outlet right ventricle with pulmonic stenosis may present a surgical challenge because severe associated anomalies which definitely complicate their repair are not uncommon. We describe the anatomic details of our 14 cases of DORV with PS and the surgical results. The results having been unsatisfactory, more meticulous diagnostic studies for the detailed intracardiac morphologies and the strict indication for their repair with the refinement of surgical technique seem necessary for the better surgical results.

• Journal of Ginseng Research
• /
• v.16 no.3
• /
• pp.210-216
• /
• 1992

The effect of saponin extracted from Panax grneng CA Meyer on DNA repair and replicative DNA synthesis were examined in CHO-Kl cells cotreated with benzo(a)pyrene and rat liver S-15 fraction. The DNA strand breaks inititated by benzo(a)pyrene metabolites were measured by alkaline election technique. The addition of ginseng saponin to the culture media resulted in decrease of benzo(a)pyrene-induced DNA strand breaks, and restored the suppressed-semiconservative-DNA-synthesis by the carcinogen. DNA repair synthesis in the damaged cells was also elevated by the ginseng treatment when the repairing activites were measured for the (3H)-thymidine incorporation into the carcinogen damaged cellular DNk Comparative analysis of DNA-adduces of benzo(a)pyrene metabortes in microsomes suggested that ginseng saponin treatment in rats reduced the formation of electrophilic metabolites of benzo (a)-pyrene in the rat liver microsomes.