• Nuclear Engineering and Technology
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• v.53 no.4
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• pp.1049-1078
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• 2021

The review summarizes the published data on the widely applied electron-beam, laser-beam, as well as resistance upset, projection, and spot welding of zirconium alloys for nuclear applications. It provides the results of their analysis to identify common patterns in this area. Great attention has been paid to the quality requirements, the edge preparation, up-to-date equipment, process parameters, as well as post-weld treatment and processing. Also, quality control and weld repair methods have been mentioned. Finally, conclusions have been drawn about a significant gap between the capabilities of advanced welding equipment to control the microstructure and, accordingly, the properties of welded joints of the zirconium alloys and existing algorithms that enable to realize them in the nuclear industry. Considering the ever-increasing demands on the high-burnup accident tolerant nuclear fuel assemblies, great efforts should be focused on the improving the welding procedures by implementing predefined heat input cycles. However, a lot of research is required, since the number of possible combinations of the zirconium alloys, designs and dimensions of the joints dramatically exceeds the quantity of published results on the effect of the welding parameters on the properties of the welds.

• Structural Engineering and Mechanics
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• v.87 no.6
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• pp.517-527
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• 2023

The severe deterioration of structures has led to extensive research on the development of structural repair techniques using composite materials. Consequently, previous researchers have devised various analytical methods to predict the interface performance of bonded repairs. However, these analytical solutions are highly complex mathematically and necessitate numerous calculations with a large number of iterations to obtain the output parameters. In this paper, an artificial neural network prediction models is used to calculate the interfacial stress distribution in RC beams strengthened with FRP sheet. The R2value for the training data is evaluated as 0.99, and for the testing data, it is 0.92. Closed-form solutions are derived for RC beams strengthened with composite sheets simply supported at both ends and verified through direct comparisons with existing results. A comparative study of peak interfacial shear and normal stresses with the literature gives the usefulness and effectiveness of ANN proposed. A parametrical study is carried out to show the effects of some design variables, e.g., thickness of adhesive layer and FRP sheet.

• Journal of the Korea Institute of Building Construction
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• v.23 no.2
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• pp.133-142
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• 2023

In this study, the fire resistance capabilities of polypropylene fiber-reinforced polymer-modified cement mortar were assessed to guarantee the fire resistance fo this materials, commonly employed in the repair of concrete structures. Experimental outcomes revealed that an increased water and polymer content heightened the likelihood of spalling, while longer polypropylene fibers and elevated polymer concentrations proved more effective in mitigating spalling.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2021.05a
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• pp.49-50
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• 2021

However, in the case of concrete, there is a concern that carbonation may proceed due to environmental factors. However, in the case of concrete, there is a concern that carbonation may proceed due to environmental factors. Research is steadily underway to prevent carbonation because carbonation decreases durability and increases the risk from disasters. However, there are many cases in which studies related to carbonation have been conducted only with materials in the same space. Therefore, in this study, FT-IR was used to analyze the difference in carbonation components by structural parts of old buildings. As a result, it was confirmed that there was a difference in peak values for each structural part of the building. The difference in peak values was determined to indicate differences in components, so the level of carbonation progress was different, and it is believed that differentiated repair and reinforcement methods will be needed depending on the structure.

• Steel and Composite Structures
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• v.44 no.4
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• pp.569-586
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• 2022

This study introduces a novel friction damper as a component of a recentering frame connection, to solve the problem of structural repair costs, caused by stiffness deterioration and brittle fracture of the central brace frame (CBF). The proposed damper consists of shape memory alloy (SMA) bars with pretension applied to them to improve the stability. SMAs reduce the residual displacement by virtue of the properties of the materials themselves; in addition, a pretension can be applied to partially improve their energy dissipation capacity. The damper also consists of a friction device equipped with friction bolts for increased energy dissipation. Therefore, a study was conducted on the effects of the friction device as well as the pretension forces on the friction damper. For performance verification, 12 cases were studied and analyzed using ABAQUS program. In addition, the friction and pretension forces were used as variables in each case, and the results were compared. As a result, when the pretension and friction force are increased, the energy dissipation capacity gradually increases by up to about 94% and the recentering capacity decreases by up to about 55%. Therefore, it has been shown that SMA bars with adequate pretension in combination with bolts with adequate frictional force effectively reduce residual deformation and increase damper capacity. Thus, this study has successfully proposed a novel friction damper with excellent performance in terms of recentering and energy dissipation capacity.

• Structural Monitoring and Maintenance
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• v.10 no.3
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• pp.221-242
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• 2023

Internal and external corrosion are common in pressure pipes used in a variety of industries, often resulting in defects that compromise their integrity. This economically and industrially significant problem calls for both preventive and curative technical solutions to guarantee the reliability of these structures. With this in mind, our study focuses on the influence of composite and metallic patch repairs on the limit loads of pipes, particularly elbows, the critical component of piping systems. To this end, we used the nonlinear extended finite element method (X-FEM) to study elbows, a priori corroded on the internal surface of the extrados section, then repaired with composite and metallic patches. In addition, the effect of the geometry of composite materials and metal patches was examined, in particular the effect of their thickness and material on the increase in limit loads of repaired structures. The results obtained provide information on the effectiveness and optimization of patch repair of corroded elbows, with the aim of increasing their service life.

• Journal of Practical Agriculture & Fisheries Research
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• v.25 no.4
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• pp.67-77
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• 2024

This study analyzed the profitability and diagnosed business performance of fruit and vegetable (cherry tomatoes, tomatoes, strawberries, cucumbers) businesses targeting young farmers participating in the youth business incubation center of A Smart Farm Innovation Valley. The purpose of this is to provide basic data for decision-making by prospective young entrepreneurs. As a result of the analysis, Smart Farm Innovation Valley had the advantage of having a fixed rental fee. As a result, it was analyzed that various costs such as depreciation of large farm equipment, depreciation of farming facilities, repair and maintenance costs, land rent, floating capital service cost, fixed capital service cost, and land capital service cost are being reduced. However, excessive input of labor, water, electricity, other materials, and fertilizer costs was being made. Guidance to reduce these costs is expected to make a significant contribution to expanding the influx of young farmers.

• Asian Pacific Journal of Cancer Prevention
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• v.15 no.11
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• pp.4535-4538
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• 2014

Objective: To explore the value of porous titanium alloy plates for chest wall reconstruction after resection of chest wall tumors. Materials and Methods: A total of 8 patients with chest wall tumors admitted in our hospital from Jan. 2006 to Jan. 2009 were selected and underwent tumor resection, then chest wall repair and reconstruction with porous titanium alloy plates for massive chest wall defects. Results: All patients completed surgery successfully with tumor resection-induced chest wall defects being $6.5{\times}7cm{\sim}12{\times}15.5$ cm in size. Two weeks after chest wall reconstruction, only 1 patient had subcutaneous fluidify which healed itself after pressure bandaging following fluid drainage. Postoperative pathological reports showed 2 patients with costicartilage tumors, 1 with squamous cell carcinoma of lung, 1 with lung adeno-carcinoma, 1 with malignant lymphoma of chest wall, 2 with chest wall metastasis of breast cancers and 1 with chest wall neurofibrosarcoma. All patients had more than 2~5 years of follow-up, during which time 1 patient with breast cancer had surgical treatment due to local recurrence after 7 months and none had chest wall reconstruction associated complications. The mean survival time of patients with malignant tumors was ($37.3{\pm}5.67$) months. Conclusions: Porous titanium alloy plates are safe and effective in the chest wall reconstruction after resection of chest tumors.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.18 no.3
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• pp.371-377
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• 1996

Bone graft has been used to repair one defect caused by disease and trauma, congenital and acquired deformities. Graft materials are autogenous bone, allogenic bone, xenogenic bone, synthetics. Autogenous bone graft is the most superior to other materials for immunologic reaction, compatibility to host tissue, and revascularization. However, autogenous bone graft is required for additional operation and the amount of taking is limited. Autografts are obtained at own expense and also limited in size, shape. In order to compensate these problems, allogenic bone graft has been used increasingly. But allogenic bone graft encounters immunologic complications. Therefore, it has been used after freezing, lyophilization, or demineralization. Allogenic bone processed by only lyophilization includes potential antigenic properties on its surface, therefore it is demineralized to deplete immunologic reaction. Demineralized bone releases BMP and helps the mesenchymal cells transform to the chondroblast to produce cartilage and bone. This reaction is called osteoinducation. Many authors have reported that mineralized lyophilized bone had less antigenicity clinically and favorable bony consideration with host bone. In our department from 1995 to now, we have used banked allogenic bone graft that has been prepared from Wonkwang Bone Bank in 5 cases and mineralized lyophilized bone graft in 2 cases to reconstruct the maxillofacial bone defect after tumor resection and cyst enucleation and cleft alveolus. We will report with literature review that the result is favorable functionally and esthetically.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.41
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• pp.60.1-60.6
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• 2019

Background: The lingual nerve plays an important role in multiple functions, including gustatory sensation and contact sensitivity and thermosensitivity. Misdiagnosed conservative treatments for serious lingual nerve (LN) injuries can induce the patient to serious mental disability. After continuous observation and critical diagnosis of the injury, in cases involving significant disruption of lingual nerve function, microneurosurgical reconstruction of the nerve is recommended. Direct anastomosis of the torn nerve ends without tension is the recommended approach. However, in cases that present significant gaps between the injured nerve ends, nerve grafts or conduits (tubes of various materials) are employed. Recently, various reconstruction materials for peripheral nerves were commercially offered especially in the USA, but the best method and material is still unclear in the world. There currently exists no conventional protocol for managing LN neurosensory deficiency in regard to optimal methods and the timing for surgical repair. In Japan, the allograft collagen nerve for peripheral nerves reconstruction was permitted in 2017, and we tried to use this allograft nerve and got a recommendable result. Case presentation: This report is a long-term abandoned torn LN reconstructed with allograft nerve induced by the lower third molar extraction. Conclusions: In early sick period, with the exact diagnosis, the LN disturbance should be managed. In a serious condition, the reconstruction with allograft nerve is one of the recommendable methods.