• Transactions of the Korean Society of Automotive Engineers
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• v.18 no.3
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• pp.37-42
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• 2010

Plastic region tightening is widely used in critical bolted joints in internal combustion engines in order to reduce the engine weight by maximizing the use of load-carrying capacity of bolt. Mechanical behavior of bolt tightened in plastic region under external axial tensile load is investigated for various friction conditions using three dimensional finite element analysis. The behavior of bolt tightened in elastic region as well as that in tensile test are investigated for comparison. Tightening process is simulated by rotating the bolt in order to examine the friction effect realistically. It is revealed that the bolt tightened in plastic region can carry more external load until the joint is opened, and yields at lower bolt load than the bolt tightened in elastic region. The friction coefficient has effect on the yield load, but not on the load-carrying capacity. Moreover, the scatter in the bolt preload due to friction begins with plastic deformation of bolt in the angle tightening control, whereas it begins with the onset of tightening in the torque tightening control. The observations are interpreted with the residual torsional stress in the bolt generated during the tightening.

• Journal of the Korea institute for structural maintenance and inspection
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• v.6 no.3
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• pp.167-175
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• 2002

In this paper, an analytical model is proposed for analyzing the hysteretic behavior of RC beam with relocated plastic hinge region under load reversals. The plastic hinge is modeled not to be concentrated on a point but to be distributed on a finite size in beam. This is based on the assumption that the plastic hinge is formed over a certain region, in which the curvature varies. Tangential matrix is reformed using stiffness coefficients including variales such as the length and location of plastic hinge region. In order to construct the hysteretic rule of hinge, modified Takeda rule is also proposed on the base of regression analysis for the previous test results. Previous specimens are analyzed using the proposed model and the result is compared with test result. On the result of the comparison, it was shown that the hysteretic behavior of beams with different location of plastic hinge region could be prediced using the proposed analytical process.

• Archives of Plastic Surgery
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• v.45 no.3
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• pp.271-274
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• 2018

The decision of which surgical approach to use for the treatment of a multifocal craniofacial abscess is still a controversial matter. A failure to control disease progress in the craniofacial region can potentially put the patient's life at risk. Therefore, understanding the various ways to approach the craniofacial region helps surgeons to obtain satisfactory results in such cases. In this report, we describe a patient who visited the emergency department with a large swelling in his right cheek. A blood test and computed tomography revealed odontogenic maxillary sinusitis. The patient developed sepsis due to a progressive multifocal abscess. An abscess was seen in the temporal muscle, infratemporal fossa, and interorbital region. To control this multifocal abscess, we used the facial dismasking flap (FDF) approach. After debridement using the FDF approach, we succeeded in obtaining sufficient drainage of the abscess, and the patient recovered from sepsis. The advantages of the FDF approach are that it provides a wide surgical field, extending from the parietal region to the mid-facial region, and that it leaves no aesthetically displeasing scars on the face. The FDF approach may be one of the best options to approach multifocal abscesses in the craniofacial region.

• Structural Engineering and Mechanics
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• v.72 no.6
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• pp.675-687
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• 2019

As the bridges are an integral part of the transportation network, their function as one of the most important vital arteries during an earthquake is fundamental. In a design point of view, the bridges piers, and in particular the wall piers, are considered as effective structural elements in the seismic response of bridge structures due to their cantilever performance. Owing to reduced seismic load during design procedure, the response of these structural components should be ductile. This ductile behavior has a direct and decisive correlation to the development of plastic hinge region at the base of the wall pier. Several international seismic design codes and guidelines have suggested special detailing to assure ductile response in this region. In this paper, the parameters which affect the length of plastic hinge region in the reinforced concrete bridge with wall piers were examined and the sensitivity of these parameters was evaluated on the length of the plastic hinge region. Sensitivity analysis was accomplished by independently variable parameters with one standard deviation away from their means. For this aim, the Monte Carlo simulation, tornado diagram analysis, and first order second moment method were used to determine the uncertainties associated with analysis parameters. The results showed that, among the considered design variables, the aspect ratio of the pier wall (length to width ratio) and axial load level were the most important design parameters in the plastic hinge region, while the yield strength of transverse reinforcements had the least effect on determining the length of this region.

• Proceedings of the KSME Conference
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• 2004.04a
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• pp.420-425
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• 2004

Lee and Kang measured side-necking deformation near a crack-tip for CT specimen using Stereoscopic Digital Speckle Photography and Digital Image Correlation. In this work the same technique was applied to SENB specimen. We happened to find that the deformation shape of the side-necking is similar to the one of plastic region estimated by McClictock using slip line theory. Based on volume constancy of plastic deformation as well as this finding, it is expected that a linear relationship holds between the volume of plastic deformation region and the one of side-necking upon the lateral surface of a specimen. To prove the idea, a preliminary study has been performed using 3-D finite element method on a model with modified boundary layer formulation. As the result, it is shown that the idea works well with acceptable error.

• Archives of Plastic Surgery
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• v.41 no.6
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• pp.673-678
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• 2014

Background The depth of graft harvest and the residual dermis available for reepithelization primarily influence the healing of split-skin graft donor sites. When the thigh region is chosen, the authors hypothesize based on thickness measurements that the anterolateral region is the optimal donor site. Methods Full-thickness skin specimens were sampled from the anteromedial, anterior, and anterolateral regions of human cadavers. Skin specimens were cut perpendicularly with a custom-made precision apparatus to avoid the overestimation of thickness measurements. The combined epidermal and dermal thicknesses (overall skin thickness) were measured using a digital calliper. The specimens were histologically stained to visualize their basement membrane, and microscopy images were captured. Since the epidermal thickness varies across the specimen, a stereological method was used to eliminate observer bias. Results Epidermal thickness represented 2.5% to 9.9% of the overall skin thickness. There was a significant difference in epidermal thickness from one region to another (P<0.05). The anterolateral thigh region had the most consistent and highest mean epidermal thickness ($60{\pm}3.2{\mu}m$). We observed that overall skin thickness increased laterally from the anteromedial region to the anterior and anterolateral regions of the thigh. The overall skin thickness measured $1,032{\pm}435{\mu}m$ in the anteromedial region compared to $1,220{\pm}257{\mu}m$ in the anterolateral region. Conclusions Based on skin thickness measurements, the anterolateral thigh had the thickest epidermal and dermal layers. We suggest that the anterolateral thigh region is the optimal donor site for split-skin graft harvests from the thigh.

• Archives of Plastic Surgery
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• v.48 no.6
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• pp.660-669
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• 2021

Background The demand for aesthetic procedures continues to grow globally, particularly in East Asian countries. The popularity of specific aesthetic procedures varies, however, depending on the particular East Asian geographical region being studied. This study aimed to evaluate the experiences of and attitudes toward aesthetic procedures in five East Asian countries/regions, including China, Japan, South Korea, Hong Kong, and Taiwan. Methods To recruit participants, an online questionnaire was designed and distributed on social media networks between May 2015 and March 2016. The statistical analysis was conducted using SPSS software, version 22.0. Results A total of 3,088 people responded (approximately 600 in each country/region). Of these, 940 participants (47.8%) responded that they had experienced at least one aesthetic procedure in the past. Taiwan had the highest number of participants who had experienced at least one procedure (264/940, 41%), with primarily non-surgical experiences. Only in South Korea did surgical cosmetic experiences exceed non-surgical cosmetic experiences (55.9% vs. 44.1%). The popularity of particular procedures and the motivation for undergoing aesthetic procedures varied by country. Conclusions The popularity of aesthetic procedures continues to evolve. Similar trends were observed across the East Asian regions; however, each country had its unique demands and preferences. The information provided by this study can help aesthetic plastic surgeons further understand the patients in their corresponding region, customize their practice, and develop the requisite skills.

• Journal of Advanced Marine Engineering and Technology
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• v.33 no.4
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• pp.539-544
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• 2009

The constraint effect $A_2$ has to be evaluated within plastic region near crack tip front using opening displacement. Plastic boundary and stress or strain conditions in the vicinity of the crack tip using recrystallization heat treatment was represented. It was found that the plastic deformation boundary by recrystallization heat treatment method was the true strain of ${\epsilon}t$ = 0.05mm/mm. With the estimation of constraint effects $A_2$, the region of proper displacement measurement point near crack tip was between 0mm and 1mm distance toward direction of crack propagation, and was between 1mm to 3mm distance toward direction of load line.

• Archives of Reconstructive Microsurgery
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• v.14 no.2
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• pp.125-130
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• 2005

The purpose of this study is to introduce a sensory restoration in reconstructed breast with free TRAM flap to evaluate recovery aspect and recovery quantity. 144 patients underwent breast reconstruction with free TRAM flap by authors and were followed up at the out patient clinique. We discovered that sensory of operated breast was recoverd. We divide the breast into 5 region (upper medial, lower medial, upper lateral, lower lateral, nipple areolar complex) for examining the sensory restoration. Sense of upper medial region & upper lateral region is recovered more quickly than other region. Touch sensation was recovered more quickly than pain sensation, temperature sensation, vibratory sensation. After about 1 year all protective sensation was recovered in all patient. We discovered that severe postop scar and irradiation of breast is related to delayed sensory recovery, age and size of flap is not related to sensory recovery.

• Archives of Craniofacial Surgery
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• v.24 no.2
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• pp.73-77
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• 2023

Hidradenitis suppurativa (HS) is a chronic inflammatory condition that is difficult to diagnose, with a period of 10.0±9.6 years from symptom onset to diagnosis. A 32-year-old Asian man presented with bilateral postauricular abscesses that first appeared 5 years previously. Despite several incisions and drainage, the symptoms only temporarily improved and continued to recur. On physical examination, chronic scars and sinus tracts were observed around the lesion. Postauricular HS was diagnosed, and surgical treatment was performed. We performed a wide excision and reconstructed the defect using a posterior auricular artery perforator-based keystone flap. Histological examination confirmed the diagnosis of HS. The reconstruction was successful, and there was no recurrence for 2 years after surgery. HS is difficult to diagnose without specific attention. Although the postauricular region is not a typical site of HS, it can occur in this area. Therefore, if a patient presents with recurrent abscesses in the postauricular region, HS should be considered. Additionally, if HS is diagnosed in the postauricular region, wide excision with reconstruction using a posterior auricular artery perforator-based keystone flap can lead to a favorable outcome.