• Journal of Welding and Joining
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• v.29 no.2
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• pp.64-71
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• 2011

In this paper, crack propagation analyses in the inner diameter (ID) repair weld of the dissimilar metal weldment of a nozzle were performed using a finite element alternating method (FEAM). To calculate the theoretical solution for the crack tip stress intensity factor, a weak type singular integral equation consisted of crack surface traction and dislocation density function was constructed and solved in conjunction with the FEAM. A two-dimensional axisymmetric finite element nozzle model was prepared and ID repair welding was simulated. An initial crack, 10% depth of weld thickness, was assumed and crack propagation trajectory from the initial crack to the 75% depth of thickness was calculated using the FEAM. Crack growth versus time curve was also calculated and compared with the curves obtained from ASME code method. With the method constructed in this paper, crack propagation trajectory and crack growth time were calculated automatically and effectively.

• Structural Engineering and Mechanics
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• v.61 no.1
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• pp.1-13
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• 2017

The effectiveness of the repair scheme for the damaged captive-columns with CFRPs (Carbon Fiber Reinforced Polymer) was investigated in terms of response quantities such as strength, ductility, dissipated energy and stiffness degradation. Two 1/3 scale, one-story one-bay RC (Reinforced Concrete) frames were designed to represent the substandard RC buildings in Turkish building stock. The first one, which is the reference specimen, is the bare frame without infill wall. Partial infill wall with opening was constructed between the columns of the second frame and this caused captive column defect. Severe damage was observed with the concentration of shear cracks in the second specimen columns. Then, the damaged members were repaired by CFRP wrapping and retested. For the three test series, similar reversed cyclic lateral displacement under combined effect of axial load was applied to the top of the columns. Overall response of the bare frame was dominated by flexural cracks. Brittle type of shear failure in the column top ends was observed in the specimen with partial infill wall. It was observed that former capacity of damaged members of the second frame was recovered by the applied repair scheme. Moreover, ultimate displacement capacity of the damaged frame was improved considerably by CFRP wrapping.

• Journal of Chest Surgery
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• v.25 no.11
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• pp.1254-1260
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• 1992

Rupture of the posterior left ventricular wall following mitral valve replacement is a rare but fatal complication. Over a 10 year period from August 25 1980 to November 27 1990, we have experienced 6 such patients among 884 cases of mitral valve replacement with 4 deaths and 2 survivors. One patient had a type I rupture and another a type II rapture with the remaining four patients having suffered type III ruptures. All of the ruptures were dis covered intraoperatively enabling prompt reinstitution of the cardiopulmonary bypass and subsequent cardioplegic arrest prior to repair. Overzealous removal of calcified valve leaflets seemed to be responsible for the single type I rupture, and untethering of the so called ventricular loop appeared to be the main mechanism responsible for the type III ruptures. The single type II rupture that had occurred seemed to have been caused by inadvertent laceration of the papillary muscle with resultant rupture of the posterior LV wall at the base of the papillary muscle. Among the type III ruptures, 2 patients required intraaortic balloon pump[IABP] support only for mechanical assistance and 1 patient required both the IABP and the Biomedicus LV assist device for successfull weaning following repair of the LV rupture Another patient with a type II rupture also required the circulatory assistance of both the IABP and the bio-medicus LV assist device for weaning from the bypass. Attention to meticulous technical considerations such as avoiding over aggressive removal of heavily calcified valvular tissue, preservation of as much mural leaflet tissue and chordal stuctures as possible seemed helpful in preventing this catastrophic complication from occurring. Fusion and fibrous stricture of the chordal structures appeared particularly conducive to the type II ruptures as a result of the increased susceptibility to papillary injury during operation.

• Proceedings of the Korea Concrete Institute Conference
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• 2008.04a
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• pp.621-624
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• 2008

Repair materials which applied to the concrete structures may have different quality characteristics depending on the environmental factors. Evaluation on durability of domestic repair materials have not yet secured enough quality performance on durability, mainly due to the lack of test methods resulted from various environmental factors. In this study, we carried out the tests on freezing and thawing resistance of domestic repair materials with different environmental factors applied under BS EN 13687, and analyzed the results by comparing with Korea's national test standards(KS F 4716). The results indicate that after the repetition of dry and wet conditions and the test on freezing and thawing with salt immersion resistance bond strength might show great difference depending on the type of repair materials and the size of sample. For securing better quality performance of repair materials, it is required to establish various standards on the test methods of freezing and thawing resistance with different environmental factors applied.

• Tribology and Lubricants
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• v.38 no.3
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• pp.93-100
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• 2022

Micro-light emitting diode (micro-LED) displays offer numerous advantages such as high brightness, fast response, and low power consumption. Hence, they are spotlighted as the next-generation display. However, defective LEDs may be created due to non-uniform contact loads or LED alignment errors. Therefore, a repair process involving the replacement of defective LEDs with favorable ones is necessitated. The general repair process involves the removal of defective micro-LEDs, interconnection material transfer, as well as new micro-LED transfer and bonding. However, micro-LEDs are difficult to repair since their size decreases to a few tens of micron in width and less than 10 ㎛ in thickness. The conventional nozzle-type dispenser for fluxes and the conventional vacuum chuck for LEDs are not applicable to the micro-LED repair process. In this study, transfer conditions are determined using a micro stamp for repairing micro-LEDs. Results show that the aging time should be set to within 60 min, based on measuring the aging time of the flux. Additionally, the micro-LEDs are subjected to a compression test, and the result shows that they should be transferred under 18.4 MPa. Finally, the I-V curves of micro-LEDs processed by the laser and hot plate reflows are measured to compare the electrical properties of the micro-LEDs based on the reflow methods. It was confirmed that the micro-LEDs processed by the laser reflow show similar electrical performance with that processed by the hot plate reflow. The results can provide guidance for the repair of micro-LEDs using micro stamps.

• Physical Therapy Korea
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• v.30 no.1
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• pp.41-49
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• 2023

Background: Scapular dyskinesis may cause not only rotator cuff (RC) tear but also weakness of the upper extremity, studies on scapular dyskinesis that may occur after RC repair is still lacking. Objects: To determine whether scapular dsykinesis was present in patients after arthroscopic RC repair and to investigate the influence of passive scapular stabilization on upper extremity strength. Methods: A total of 30 patients after RC repair participated in this study. To compare the scapula of the arthroscopic RC repair shoulder and the contralateral shoulder, the winged scapula (WS) was measured using a scapulometer and scapular dyskinesis was also classified by type. Fixed instruments for muscle strength measurements were used to measure upper extremity muscle strength differences depending on passive scapular stabilization position or natural scapular position. A chi-square test, an independent t-test and a 2-way mixed measures analysis of variance (ANOVA) was used as statistical analysis. In analyses, p < 0.05 was deemed to be statistically significant. Results: Postoperative shoulder had a significant association with scapular dyskinesis and the WS compared to the contralateral shoulder (F = 0.052, p < 0.01). Postoperative shoulder, muscle strength in the shoulder abduction (p < 0.01), elbow flexion (p < 0.01) and forearm supination (p < 0.05) were significantly greater in the scapular stabilization position than in the scapular natural position. Conclusion: Patients underwent arthroscopic RC repair had a significant association with scapular dyskinesis and muscle strength was improved by a passive scapular stabilization position, therefore scapular stabilization is important in rehabilitation program.

• Clinics in Shoulder and Elbow
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• v.26 no.1
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• pp.71-81
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• 2023

Background: This study evaluated the clinical and radiologic outcomes of onlay patch augmentation in rotator cuff repair for moderate-to-large tears in elderly patients. Methods: We reviewed 24 patients who underwent onlay augmentation with dermal allograft after arthroscopic rotator cuff repair from January 2017 to March 2020. Inclusion criteria were patients aged >65 years with tears >2.5 cm, who were followed for >12 months after surgery, and patients who could raise their arms above 90° preoperatively. American Shoulder and Elbow Surgeons (ASES) score, Constant-Murley score, pain visual analog scale (VAS), and VAS for satisfaction were used as clinical outcomes. For the evaluation of cuff integrity, magnetic resonance imaging scans were performed every 3 months after surgery. The results were compared before and after surgery in all patients and between the retear and intact groups. Results: The average follow-up period was 16.38 months, and the mean age of patients was 71.05 years. All patients showed significant improvement in ASES score, Constant-Murley score, and pain VAS at the last evaluation. The average value of satisfaction VAS was 7.27/10. The retear rate was 25% (6/24) if Sugaya type 3 was categorized in the retear group, otherwise 16.7% (4/24), if Sugaya type 3 was categorized into the intact group. Irrespective of Sugaya type 3 being included in the retear group, there was no significant difference in outcome variables between the intact and retear groups during follow-up. Conclusions: In moderate-to-large rotator cuff tear in elderly patients, onlay patch augmentation improved clinical outcomes. Retear did not adversely affect clinical outcomes.

• Korean Journal of Radiology
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• v.22 no.4
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• pp.577-583
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• 2021

Objective: To report the authors' experience in performing thoracic endovascular aortic repair (TEVAR) for zone 2 lesions after traumatic aortic injury (TAI). Materials and Methods: This retrospective review included 10 patients who underwent zone 2 TEVAR after identification of aortic isthmus injury by CT angiography (CTA) upon arrival at the emergency room of a regional trauma center from 2016 to 2019. Patients were classified into two groups: those who underwent left subclavian artery (LSA) embolization concurrently with the main TEVAR procedure, and those in whom LSA embolization was not performed during the main procedure, but was planned as a bailout treatment if type II endoleak was noted on follow-up CTA images. Pre-procedural and procedure-related factors and post-procedure prognosis were compared between the groups. Results: There were no differences in pre-procedural factors, occurrence of endoleaks, and post-procedure prognosis (including mortality) between patients in the two groups. The duration of the procedure was shorter in the non-LSA embolization group (61 minutes vs. 27 minutes, p = 0.012). During follow-up, type II endoleak did not occur in either group. Conclusion: Delaying preventative LSA embolization until stabilization of the patient would be desirable when performing zone 2 TEVAR for TAI, in the absence of endoleak on the completion aortography image taken after complete deployment of the stent graft.

• Journal of Chest Surgery
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• v.40 no.12
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• pp.855-858
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• 2007

A left ventricular rupture might be one of the most disastrous complications after a mitral valve replacement. An acute atrioventricular groove rupture (type I) was detected in a 54-year-old female diagnosed with a mitral stenosis combined with severe tricuspid regurgitation. She had a prior medical history of an open mitral commissurotomy in Japan at 30 years ago. The surgical findings suggested that the previous procedure was not a simple commissurotomy but a commissurotomy combined with a posteromedial annuloplasty procedure. After a successful mitral valve replacement and a measured (De Vega type) tricuspid annuloplasty, the weaning from a cardiopulmonary bypass was uneventful. However, copious intraoperative bleeding from the posterior wall was detected and the cardiopulmonary bypass was restarted. Exposure of the posterior wall of the left ventricle showed bleeding from the atrioventricular groove 3 cm lateral to the left atrial auricle. Under the impression of a Type I left ventricular rupture, epicardial repair (primary repair of the Teflon felt pledgetted suture, continuous sealing suture using auto-pericardial patch and application of fibrin-sealant) was attempted. Successful local control was made and the patient recovered uneventfully. The patient was discharged at 14 postoperative days without complications. We report this successful epicardial repair of an acute type I left ventricular rupture after mitral valve replacement.

• Journal of Chest Surgery
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• v.47 no.2
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• pp.167-170
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• 2014

Herein, we present a case of a successful treatment of persistent type 2 endoleaks associated with aneurysmal sac enlargement after endovascular aneurysm repair in an elderly patient. We confirmed the diagnosis by abdominal computed tomography and selective angiography revealing an 11.0-cm aneurysm sac with type 2 endoleaks. An attempt for the endovascular embolization of collateral arteries was unsuccessful due to anatomic variations and their multiple complex communications. Instead, transperitoneal sacotomy and direct suturing on the feeding target vessels was successfully performed without any endograft damage. In conclusion, sacotomy appears to be a feasible therapeutic substitute where endovascular or other techniques have a high risk of failure and lead to unsuccessful results.