• Archives of Plastic Surgery
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• v.39 no.5
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• pp.509-513
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• 2012

Background The extended latissimus dorsi flap is important for breast reconstruction. Unfortunately, donor site seroma is the most common complication of extended latissimus dorsi flap for breast reconstruction. Although using fibrin sealant in the donor site reduces the rate of seroma formation, donor site seroma remains a troublesome complication. The purpose of this study was to analyze the effectiveness of the combination of quilting sutures and fibrin sealant in the latissimus dorsi donor site for the prevention of seroma. Methods Forty-six patients who underwent breast reconstruction with extended latissimus flap were enrolled in the study. The patients received either fibrin sealant (group 1, n=25) or a combination of fibrin sealant and quilting sutures (group 2, n=21) in the extended latissimus dorsi donor site. Outcome measures were obtained from the incidence, volume of postoperative seroma, total drainage amount, indwelling period of drainage, and duration of hospital stay. Results The incidence of seroma was 76% in group 1 and 42.9% in group 2 (P=0.022). We also found significant reductions in seroma volume (P=0.043), total drainage amount (P=0.002), indwelling period of drainage (P=0.01), and frequency of aspiration (P=0.043). The quilting sutures did not affect the rate of drainage, tube reinsertion, or hospital stay. Conclusions The use of quilting sutures combined with fibrin sealant on the latissimus dorsi flap donor site is helpful for reducing the overall seroma volume, frequency of aspiration, and total drainage amount.

• Journal of the Korean Society of Radiology
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• v.10 no.6
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• pp.435-442
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• 2016

This study was an investigation of the anode heel effect caused by changing the angle of the x-ray tube. We established the following conditions for experimental measurements: 70 kV, 30 mAs, focus-detector distance of 100cm, and a collimator setting of $35{\times}43cm^2$. The measurement points were set up at the center of the collimator and extended to each side in intervals of 3.5cm, with points A1, A2, A3, A4, A5, A6 on the anode side and points C1, C2, C3, C4, C5, C6 on the cathode side. We measured the entrance surface dose from point A6 to point C6 with each point perpendicular to an x-ray tube. And we did the same when measuring different angles of the x-ray tube from 15 to 30 degrees for every point on the anode and cathode sides. Using perpendicular x-ray tube, we found that the entrance surface dose of the A5 point was three times higher than that of the C5 point. Thus, we conclude that if the anode side is placed near highly radiosensitive organs, then there will be less radiation exposure when using a perpendicular x-ray tube. When imaging using x-ray tube angles, an angle to the cathode side can reduce the gap of the entrance surface dose on both the anode and cathode sides. When imaging areas where there are differences in thickness between the upper and lower sides, the angle to the cathode side that is closer to the thicker area can reduce the gap of the entrance surface dose and capture a higher quality image.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.6
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• pp.18-25
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• 2016

Enhanced tubes are used widely in the evaporators of large tonnage compression-type refrigerators. The evaporators consist of tube bundles, and the refrigerant properties are dependent on the locations in the tube bundles. In particular, the saturation temperatures of low pressure refrigerants (R-11, R-123) are strongly dependent on the locations due to the saturation temperature-pressure curve characteristics. Therefore, for the proper design of evaporators, local property predictions of the refrigerants are necessary. In this study, a computer program that simulates the flooded refrigerant evaporators was developed. The program incorporated theoretical models to predict the refrigerant shell-side boiling heat transfer coefficients and pressure drops across the tube bundle. The program adopted an incremental iterative procedure to perform row-by-row calculations over the specified incremental tube lengths for each water-side pass. The program was used to simulate the flooded refrigerant evaporator of the "T" company operating with R-123, which yielded satisfactory results. The program was extended to predict the performance of the flooded refrigerant evaporator operating with R-11, R-123, and R-134a. The effects of bundle aspect ratio are investigated.

• Proceedings of the KSME Conference
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• 2001.06d
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• pp.201-207
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• 2001

We modeled the liquid film dryout(LFD) process for both tube and annulus which have uniformly heated vertical channels. We set phenomenological initial conditions in the model. The initial void fraction on the onset of the annular flow location is derived from the physical chum-to-annular flow criterion with the help of the drift-flux-model. The initial thermodynamic-equilibrium-quality is calculated by iteration with the flow quality to find the onset of the annular-flow location. Present model tends to predict very well at the lower exit quality but under-estimates at the higher exit quality. We found that the prediction error of the present model is gradually bigger as the inlet subcooling approaches near the saturation. We obtained excellent results for both tube and annulus channels as the mean of 0.97 and root-mean-square error of 11% for the number of 3883 experimental data on tubes, and of 0.96 and of 12% for 593 on annuli. The present model extended the applicable range to the relatively low exit quality region than previous LFD models.

• Journal of Chest Surgery
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• v.7 no.2
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• pp.169-174
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• 1974

Duplication of the alimentary tract, especially of the esophagus, have been regarded as rare cong- enital anomalies. However, they are being reported with increasing frequency in the literature. In the . ,- past they have been described by a variety of names, such as "enteric cysts", "intestinal cysts", "giant diverticula", "`mediastinal cysts of foregut origin" "enterogenous cysts" and other descriptive terms. . Most authorities now agree that these anomalies are best described by the term "duplications of the alimentary tract. The duplications [of the alimentary tract] are spherical or tubular structures which poses a well developed smooth muscle layer and are lined with a mucous membrane from any part of the alimentary tract. They may occur at any place in the digestive tube from the tongue to the rectum and usually are intimately attached to some portion of the alimentary tube. We have experienced a duplication of the esophagus in 14 years old middle schoolboy. He complained dysphagia, eructation and substernal pain associated with intermittent high fever and chilliness, increasing in severity for recent three weeks. Routine chest X-ray film revealed nore markable abnormal finding but esophagogram. revealed marked narrowing of the esophagus throughout with a large blind pouch in lower half with fistulous communication at mid portion of the esophagus. On thoracotomy, a large infected blind pouch communicating with the lumen of normal esophagus proximally, Was extended from the level of 5th to 10th thoracic spine. The duplicated segment of the esophagus has a common muscular .wall and proximal communication with the adjacent esophagus. The infected, duplicated esophagus was segmentally resected, and esophagogastrostomy with pyloroplasty was done by displacing the stomach into the right thoracic cavity through midline laparotomy. His Postoperative course was uneventful and discharged without complication.

• Steel and Composite Structures
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• v.28 no.5
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• pp.541-557
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• 2018

This paper presents the influence of carbon nanotubes (CNTs) waviness and aspect ratio on the vibrational behavior of functionally graded nanocomposite sandwich annular sector plates resting on two-parameter elastic foundations. The carbon nanotube-reinforced (CNTR) sandwich plate has smooth variation of CNT fraction along the thickness direction. The distributions of CNTs are considered functionally graded (FG) or uniform along the thickness and their mechanical properties are estimated by an extended rule of mixture. In this study, the classical theory concerning the mechanical efficiency of a matrix embedding finite length fibers has been modified by introducing the tube-to-tube random contact, which explicitly accounts for the progressive reduction of the tubes' effective aspect ratio as the filler content increases. Effects of CNT distribution, volume fraction, aspect ratio and waviness, and also effects of Pasternak's elastic foundation coefficients, sandwich plate thickness, face sheets thickness and plate aspect ratio are investigated on the free vibration of the sandwich plates with wavy CNT-reinforced face sheets. The study is carried out based on three-dimensional theory of elasticity and in contrary to two-dimensional theories, such as classical, the first- and the higher-order shear deformation plate theories, this approach does not neglect transverse normal deformations. The sandwich annular sector plate is assumed to be simply supported in the radial edges while any arbitrary boundary conditions are applied to the other two circular edges including simply supported, clamped and free.

• Steel and Composite Structures
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• v.36 no.5
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• pp.587-602
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• 2020

In recent years, the composite columns have been widely used in the structures. These columns are mainly used to construct the structures with a large span and high floor height. Concrete filled tubes (CFTs) are a type of composite column, which are popular nowadays due to their numerous benefits. The purpose of this study is to investigate such frames at elevated temperatures. The method used in this research is based on section 2.2 of Eurocode 4. First, for the verification purpose, a comparison was made between the experimental results and the numerical model of the concrete filled tube. Then a composite frame was analyzed under fire temperature with different parameters. The results showed that the failure time decreased with increasing the friction of different models. Moreover, investigation of the concrete moisture content revealed that an increase in the concrete moisture content from 3% to 10% led to extended failure time for different models. For instance, in the second frame model, the failure time has increased up to 8%.

• Proceedings of the KSME Conference
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• 2000.11a
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• pp.837-842
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• 2000

In the coiling process of helical steam generator tubes of integral reactor SMART, a considerable amount of spring back, which induces dimensional inaccuracy and difficulty in fabrication, has been arised. In this research, an analytical model was derived to evaluate the amount of the spring back for steam generator tubes. The model was developed on the basis of beam theory and elastic-perfectly plastic material property. This model was extended to consider the effect of plastic hardening and the effect of the tensile force on the spring back phenomena. Parametric studies were performed for various design variables of steam generator tubes in order to minimize the spring back in the design stage. A sensitivity analysis has shown that the low yield strength, the high elastic modulus, the small helix diameter, and the large tube diameter result in a small amount of the spring back. The amount of the spring back can be controlled by the selection of adequate design values in the basic design stage and reduced to an allowable limit by the application of the tensile force to the tube during the coiling process.

• Journal of The Korean Society of Grassland and Forage Science
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• v.7 no.3
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• pp.157-161
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• 1987

In order to utilize the tuber of Jerusalem artichoke (Jerusalem tuberosus L.) which has been considered one of the most economical resources for bioenergy, the tubers of the plant were processed into silage in 11 lab-silo with three levels of mixture of concentrates i.e. 10, 20, 30%. The silage was stored for 20 to 40 days before analyses. The quality of silage was compared with those of the tube-only silage without concentrates. Aproximate composition, pH, ammonium nitrogen, total nitrogen, and organic acids were analyzed. The results obtained are summarized ; 1. With the mixture of concentrates, the water content of the silage was able to be adjusted to 70 percent and NDF significantly increased (P<0.05) while ADF significantly decreased. 2. The content of water-soluble carbohydrate (WSC) was significantly decreased in silages of the mixture of concentrate and the tuber (P<0.05), while total nitrogen and ammonium nitrogen increased. 3. Tube-only silage gave satisfaction in fermentation, particularly organic-acid fermentation. As the storage period extended, Flieg's score of the silage was improved. Conclusively, the tuber of Jerusalem artichoke found to satisfy the requirements of good silage and to be recommended as a good resource for all-inane silage provided the tuber was ensilaged with 20 to 30 percent concentrate.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 2001.11a
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• pp.245-251
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• 2001

A fretting wear tester is developed for experimental study on the fuel fretting problem of light water reactor. The feature of the developed tester is it can simulate the existence of gap between spring and fuel rod as well as different contacting force including the just-contact condition (0 N on the contact). Used are a servo-motor, an eccentric cylinder and lever mechanism for driving system. A spacer grid cell is constituted with four strap segments (each segment has a spring). This fretting wear tester can also be used as a fatigue tester of a spacer grid spring with the frequency of more than 10 Hz. It is required to simulate the frequency of the vibrating fuel rod due to flow-induced vibration in a reactor. In fretting wear test, up to two span-length of a fuel cladding tube can be accommodated. A specimen of cladding tube of one span-length is specially designed, which can be extended for two-span test. For .fatigue test, a device for clamping the spring fixture is installed additionally, Presently, the tester is designed for the condition of air environment and room temperature. The variation of the reciprocal distance is measured to check the stability of input force, which will be exerted to the cladding (for fretting wear. test) and the spring (for fatigue test) specimen.