• Nuclear Engineering and Technology
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• v.55 no.9
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• pp.3342-3351
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• 2023

High-density polyethylene (HDPE) pipelines in nuclear power plants (NPPs) have to meet high requirements for seismic performance. HDPE pipes have been proved to have good seismic performance, but joints are the weak links in the pipelines, and pipeline failures usually initiate from the defects inside the joints. Limited data are available on the seismic performance of butt-fusion joints of HDPE pipelines in NPPs, especially in terms of defects changes inside the joints after earthquakes. In this paper, full-scale shaking table tests were performed on a test section of suspended HDPE pipelines in an NPP, which included straight pipes, elbows, and 10 butt-fusion joints. During the tests, the seismic load-induced strain of the joints was analyzed by strain gauges, and it was much smaller than the internal pressure and self-weight-induced strain. Before and after the shaking table tests, phased array ultrasonic testing (PA-UT) was conducted to detect defects inside the joints. The locations, numbers, and dimensions of the defects were analyzed. It was found that defects were more likely to occur in elbows joints. No new defect was observed after the shaking table tests, and the defects showed no significant growth, indicating the satisfactory seismic performance of the butt-fusion joints.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2021.05a
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• pp.269-270
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• 2021

As the era of the Fourth Industrial Revolution arrives and the culture of contact-less was established due to the long-term COVID-19, the construction industry is striving to develop smart home services to expand the scope of information and communications technology (ICT) to provide convenience to residents. However, various defects are occurring in information and communications technology facilities in apartments, and related research is lacking. In this study, case studies and research methods of related prior studies are analyzed as a basis for identifying the types and causes of defects that occur in information and communications technology facilities. To analyze various studies, we divided them into studies on smart home Internet of Things (IoT), information and communications technology construction of apartments, and investigated their features and limitations. Plus, future research will be conducted on apartments within 10 years of completion among apartments completed by domestic construction companies to supplement the limitations of prior research. In addition, we will prepare basic data on defects of ICT construction by analyzing the major causes of defect types through the analysis of defect types and frequency by detailed work type of information and communications technology construction.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2023.05a
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• pp.337-338
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• 2023

As the number of defects in apartments has increased recently, lawsuits and disputes related to defects have also increased. As a result, the loss of time and money is enormous. Therefore, fundamental measures are needed to reduce the occurrence of defects. Therefore, the purpose of this study is to propose a plan to reduce defects, focusing on window construction. To this end, existing studies were reviewed, and data from domestic construction companies were collected and classified to organize the types of defects. Based on the classified data, eight types with a high incidence of window glass were analyzed according to the time of occurrence, and the cause and causal relationship of the defect were schematized. It aims to identify the degree of possibility of recurrence of defects for each of the eight defect types for experts and derive key management elements using the RII method. Therefore, the goal is to select key management elements of window construction that actively reflect the characteristics of the construction stage.

• International conference on construction engineering and project management
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• 2011.02a
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• pp.629-635
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• 2011

Retentions are generally considered to be intended to act as a powerful tool to incentivize contractors/subcontractors to remedy defective work in cases of non-performance. This study attempts to establish the extent to which retentions can be used for this purpose by investigating case law connected with insurance and defective work. One of the significant questions is whether retentions are sufficient to deal with construction defects or value of retentions in the rectification of defects is illusory. The cost to repair a defect may vary depending on a number of components including type, cause, magnitude and the construction stage at which the defect occurs. It is expected that a review of existing cases on defective workmanship will provide an insight on the issues and whether retentions are effective in their intended function. In order to establish their functionality, the study described in this paper investigated 6 construction insurance cases to identify the critical issues and the causes of dispute. It was found that the nature and the cause of defects were different in each case. It was also established that certain defect types not covered by insurance may be covered by retentions - potentially one of the key uses of a retention strategy. It is expected that the findings will assist in forming a view on the quantum of money that may be required paving the way for a first time understanding on a rational basis for setting up retention regime.

• Journal of the Korea Institute of Building Construction
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• v.11 no.6
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• pp.597-608
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• 2011

It has been often noted as a problem that as there are no objective and clear criteria for the repair cost estimate of persistent defects, when a claim arises in relation to an apartment construction, significantly different amounts of compensation may be given for similar defects based on the experience and tendencies of the construction experts asked to make a judgment. For this reason, this research aims to present defect managers with a more reasonable and objective estimation criteria and a system to determine the repair cost of defects based on an analysis of relevant factors. The research findings show that the historical cost system is applied first, and then a standard of estimation is used to estimate the cost for the items that are not included in the historical cost system. The criteria for the repair cost for each defect is as follows: the repair cost for defects arising from a regulation violation is determined by calculating the reconstruction cost of the parts in question after demolishing them; the repair cost for progressive defects is determined based on a contribution ratio proportional to the age of the building; the repair cost for repetitive defects is calculated by considering an alternative to maximize the intended function of the defective parts; and the repair cost for value depreciation defects is determined based on the ratio of the warranty period to the lapsed years. However, repair cost estimation for dual value depreciation defects should be studied in future research.

• Journal of the korean academy of Pediatric Dentistry
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• v.50 no.2
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• pp.192-204
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• 2023

This study aimed to determine the criteria for quantifying developmental defects of enamel in primary teeth in premature babies and to investigate the severity of developmental defects according to the gestational age, birth weight, systemic complications, and treatments received after preterm birth. Birth information, a history of complications, the duration of parenteral nutrition, and endotracheal intubation were investigated by retrospectively reviewing the admission and discharge records of premature babies in the neonatal intensive care unit. The Preterm Developmental Defects of Enamel (PDDE) index was designed by modifying the existing developmental defects of enamel index. Based on PDDE index, the evaluator scored developmental defects of enamel by classifying them as enamel hypomineralization and hypoplasia. The PDDE scores in the extremely preterm and extremely low birth weight groups were significantly higher than those in other groups. Furthermore, PDDE scores of premature babies with bronchopulmonary dysplasia, rickets, intraventricular hemorrhage, or necrotizing colitis were significantly higher than those in the control group. In addition, more than 50 days of endotracheal intubation and more than 20 days of parenteral nutrition were associated with significantly higher PDDE scores than those in the control group and were risk factors for developmental defects of enamel. This study provides basic information for identifying risk factors for developmental defects of enamel in premature babies.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.9
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• pp.403-410
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• 2017

Apartment housing has rapidly increased since the housing supply policy implemented in the late 1980s. However, various defects have occurred because the policy focused only on quantity supply, while neglected quality control. In addition, disputes related to various defects are increasing. ; accordingly, studies defects of apartment houses have been continuously conducted to solve various problems. In this study, I analyzed the research trends regarding long-term accumulated defects of apartment buildings by keyword network analysis, and suggest implications. As ananalysis method, I collected journal articles using the portal of the Korea Educational and Scientific Information Agency and constructed data analysis by filtering collected academic papers and keyword refinement. Ialso performed visualization modeling for keyword network relationships, connection degree centrality analysis, and mediation centrality analysis. The results revealed that Mortgage, Dispute, Repair, Case, Response, Condensation, Cost, Institution, Standard, and Valuation are the main keywords that characterize apartment housing defects.

• Archives of Reconstructive Microsurgery
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• v.9 no.2
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• pp.172-178
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• 2000

With esthetic concern in the reconstruction of skin and soft tissue defects of face, the use of local flap has been the method of choice. However, when there is extensive tissue loss in the face, local flaps do not provide satisfactory results. The amazing development of microsurgical technique has decreased the percentage of free flap failure, thus making free flap use in reconstruction of facial soft tissue defects. Many free flaps has been applied for reconstruction of face defects. Especially, the radial forearm flap has numerous advantages with which facial reconstruction is made possible. But, its disadvantages are ; the sacrifice of one major artery supplying the hand and donor site complications. In order to circumvent these disadvantages, we employed posterior interosseous artery(PIA) forearm free flap for the reconstruction of the face defects. The posterior interosseous forearm island flap was first described by Zancolli and Angrigiani(1985). Currently, the PIA island flap and free flap have been used for hand reconstructions. The disadvantages of the PIA flap are ; the small caliber of the pedicle, different locations of the perforating branches, and the proximity of the motor branch of the radial nerve. But, its advantages lies in preserving the major artery of the hand, minimal donor site morbidity, and fairly well matched skin texture and color, and that the flap volume is sufficient, not too bulky with convenient handling. By using this flap, we performed 1 case of tumor resection and 1 case of traumatic defect. From our experiences we conclude that it is one of many useful methods in the reconstruction of the skin and soft tissue defects of the face. We also have discussed advantages and some limitations of various free flaps for reconstruction of the face.

• Proceedings of the Korean Institute Of Construction Engineering and Management
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• autumn
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• pp.46-53
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• 2002

Although Public Construction Works in Korea have been executed according to Government Contract Act, and nature of contract is very complicated. So it is difficult to define liability for the defects. Therefore the studies on the defective performance and contractor's defects liability were remained one of the non-cultivated virgin land. As a result, contract privy waive the right to claim or generally resolve the problems. Therefore domestic and overseas liability for the defects was investigated and liability for the defects, under and after construction, on the defective performance and defects, was analysed. With a literature research, contractor's defect liability was systematically analyzed, problems were defined and resolution of the problem were suggested item by item in this study.

• Archives of Plastic Surgery
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• v.32 no.3
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• pp.314-318
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• 2005

For treatment of full thickness skin defects caused by trauma or infections, skin grafts or flaps have been the treatment of choice to date. However, in patients who are not candidates for surgery, either due to his general conditions or refusal to receive treatment, supportive methods have been the only means of care, which inherently caused psychological trauma to the patient due to uncertainties of ultimate outcome and the length of treatment. This study aimed to heal full thickness skin defects through application of topical epidermal growth factor in patients who have received 2 to 3 weeks of conservative management using medifoam $B^{(R)}$ without improvement. Six patients from March 2002 to July 2004 were enrolled. The mean size of defects was $5.4{\times}4.6cm$ in 4 patients with carcinoma and $6.4{\times}4.1cm$ in 2 patients with osmidrosis. Commercially available 0.005% EGFR solution was used, and dressing was performed once daily. All patients benefitted from the use of EGF, with closure of skin defects taking an average of 28 days in cancer patients and 22.5 days in osmidrosis cases. EGF can be used as a supportive mean of treatment in the inoperable patients with skin defects, with resultant hastening of healing shortening duration of treatment.