• Proceedings of the KSME Conference
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• 2000.04a
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• pp.43-48
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• 2000

In this study, a small punch creep(SP-Creep) test using miniaturized specimen$(10{\times}10{\times}0.5mm)$ has been described for the development of the newly semi-destructive creep test method for high temperature structural components such as headers and tubes of boiler turbine casino and rotor and reactor vessel. The SP-Creep testing technique has been applied to 2.25Cr-1Mo(STBA24) steel used widely as boiler tube material and the creep test temperature are varied at $550^{\circ}C{\sim}600^{\circ}C$. The overall deformations of SP-Creep curves are definitely depended with applied load and creep test temperature and show the creep behaviors of three steps like conventional uniaxial creep curves. The steady state creep rate${\delta}_{ss}$ of SP-Creep curve for miniaturized specimen increases with increasing creep temperature, but the exponential value with creep loading is decreased. The activation energy$(Q_{spc})$ during SP-Creep deformation with various test temperatures shows 605.7kJ/mol that is g.eater than 467.4kJ/mol reported in uniaxial creep test. This may be caused by the difference of stress states during creep deformation In two creep test. But from the experimental results, e.g. SP-Creep curve behaviors, the steady state creep rate${\delta}_{ss}$ with creep temperature, and the exponential value(n) with creep loading, it can be summarized that the SP-Creep test may be a useful test method to evaluate the creep properties of the heat resisting material.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.53 no.4
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• pp.583-587
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• 2020

Imitation fish roe (IFR) based on calcium alginate hydrogels (CAG) can be heat treated for sterilization and salted to prolong the shelf life. However, these processes change the physical properties of IFR, and it is necessary to minimize these changes. In this study, we investigated the effects of xanthan gum (XG) treatment on the quality and stability of IFR. Both non-XG and XG-treated IFRs were treated with boiling water (95℃), sodium chloride (0.5-2.0%, w/v), and autoclaving. The non-XG treated IFR shrunk slightly after the boiling water and autoclaving processes. By comparison, shrinkage of the XG-treated IFR after autoclaving was significantly reduced. The sphericity of the non-XG treated IFR was reduced by the boiling water, sodium chloride, and autoclaving treatment. However, the sphericity of the XG-treated IFR was maintained by 90% or more, preserving the IFR shape at a level visually recognized as spherical. In addition, unlike the non-XG treated IFR, the XG-treated IFR showed high rupture strength even after the salt and heat treatments. Our findings provide useful information for the industrialization of IFR based on CAG with heat and salt treatments.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.26 no.1
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• pp.55-60
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• 2002

For the development of a new creep test technique, the availability of SP-Creep test is discussed for 1Cr-0.5Mo boiler header material. And some results are also compared with those of 2.25Cr- 1Mo steel which widely uses as boiler superheater tube. The results can be summarized as follows. The load exponents(n) obtained by SP-Creep test for 1Cr-0.5Mo steel are decreased with increasing creep temperature and the values are 15.67, 13.89, and 17.13 at 550$^{circ}C$ ,575$^{circ}C$ and 600$^{circ}C$, respectively. The temperature dependence of the load exponent is given by n = 107.19 - 0.1108T. This reason that load exponents show the extensive range of 10∼16 is attributed to the fine carbide such as M$_{23}$C$_{6}$ in lath tempered martensitic structures. At the same creep condition, the secondary creep rate of 1Cr-0.5Mo steel is lower than the 2.25Cr-1Mo steel1 due to the strengthening microstructure composed by normalizing and tempering treatments. Through a SEM observation, it can be summarized that the primary, secondary, and tertiary creep regions of SP-Creep specimen are corresponding to plastic bending, plastic membrane stretching, and plastic instability regions among the deformation behavior of four steps in SP test, respectively.y.

• Korean Journal of Head & Neck Oncology
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• v.33 no.1
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• pp.73-77
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• 2017

An 81 year-old male patient presented with rapid enlargement of left lateral neck mass, diagnosed two months earlier as cervical nontuberculous mycobacterial lymphadenitis. Abscess formation and impending rupture related to aggravation of nontuberculous mycobacterial lymphadenitis was highly suspected. Unexpectedly, blood flow was detected by Doppler ultrasonography, which indicated possible vascular mass. Computed tomography demonstrated a $6.0cm{\times}4.0cm$ sized enhancing mass consistent with pseudoaneurysm of internal carotid artery. The patient underwent pseudoaneurysmectomy. Surgical drainage without adequate evaluation might have led to potentially life-threatening condition. We describe this rare case with importance of imaging screening in a neck mass.

• Journal of The Korean Society of Inherited Metabolic disease
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• v.14 no.2
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• pp.168-173
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• 2014

Vascular Ehlers-Danlos syndrome (vEDS) is an autosomal dominant disorder caused by a mutation of the type III collagen (COL3A1). The manifestation of vEDS can be seen in skin, joints, blood vessels, and internal organs. The diagnosis of vEDS often is missed until the patient presents with a life-threatening complication such as spontaneous arterial rupture or bowel perforation. We report a 16-year-old male who had recurrent right thigh hematoma after simple exercise and minor trauma, respectively. He had a history of surgery due to spontaneous colon perforation at his age of 11 years. Gene test of COL3A1 revealed a novel mutation c.2931+dupT.

• Advances in pediatric surgery
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• v.6 no.2
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• pp.143-148
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• 2000

Pseudoaneurysm of the splenic artery may arise from a vascular erosion by a surrounding inflammatory processes in acute and chronic pancreatitis. Rupture of the pseudoaneurysm may threaten the patient's life. Conservative management for massive hemorrhage may cause 100 percent mortality and even with prompt therapy there is a high mortality. Preoperative detection of bleeding source is desirable because of the difficult identification of the bleeding site at laparotomy. Angiographic identification and embolization of the hemorrhagic vessels in selected cases may obviate the risk of urgent surgery. The authors have recently managed a case of ruptured splenic artery pseudoaneurysm combined with a pancreatic pseudocyst in a 6 years old boy. A bolus enhanced CT scan and angiography confirmed the diagnosis. We managed this child successfully with the urgent transcatheter arterial embolization followed by elective surgery.

• Tuberculosis and Respiratory Diseases
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• v.62 no.1
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• pp.62-66
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• 2007

A bronchial artery aneurysm is a rare condition, which needs optimal treatment due to the possibility of a life-threatening hemorrhage by rupture. The surgical removal of the aneurysm is the standard treatment. However, there are a few reports of coil embolization with a transcatheter. A 69 year-old man was referred for a further evaluation of a mass in the right hilum on chest radiography. He denied any respiratory symptoms. A chest CT scan showed a $3{\times}3{\times}4.5cm$ sized vascular mass with strong contrast enhancement on the right hilar area that originated from the bronchial artery. On the angiogram, the bronchial artery originated from the descending thoracic aorta at the T8 level. A bronchial artery aneurysm was catheterized selectively. and embolized successfully with a coil. After coil embolization, the selective bronchial arteriography confirmed complete occlusion. We report this case of bronchial aneurysm that was treated successfully with coil embolization.

• Journal of the Korean Society for Railway
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• v.12 no.5
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• pp.641-648
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• 2009

Concrete structures become more common in railway systems with an advancement of high speed train technologies. As the service life of concrete structures increases, structural strengthening for concrete structures may be necessary. There are several typical strengthening techniques using steel plate and fiber reinforced polymer (FRP) materials, which have their own inherent shortcomings. In order to enhance greater durability and resistance to fire and other environmental attacks, basalt fiber material attracts engineer's attention due to its characteristics. This study investigates bonding performance of basalt fiber sheet as a structural strengthening material. Experimental variables include bond width, length and number of layer. From the bonding tests, there were three different types of bonding failure modes: debonding, rupture and rip-off. Among the variables, bond width indicated more significant effect on bonding characteristics. In addition the bond length did not contribute to bond strength in proportion to the bond length. Hence this study evaluated effective bond length and effective bond strength. The effective bond strength was compared to those suggested by other researches which used different types of FRP strengthening materials such as carbon FRP.

• Journal of the Korean Wood Science and Technology
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• v.43 no.1
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• pp.36-42
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• 2015

This study examined true modulus of elasticity (MOE) and modulus of rigidity (G) for domestic woods with different slenderness ratios (L/D) using the static bending and stress wave tests. Bending properties of small clear wood specimen of three domestic wood species were determined at 12% moisture content. The results of this study indicated that both MOR and MOE of domestic woods were affected by the slenderness ratio. As the slenderness ratio increased, MOR and MOE increased. G and true MOE of domestic timber beams were obtained at different slenderness ratios by flexure test and stress wave test. The values reported here can be useful if these species woods are used for structural purposes. However, the reported values are only indicative and do not represent the true average of wood species due to the limited number of specimens tested.

• Journal of Chest Surgery
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• v.22 no.5
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• pp.816-822
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• 1989

Aneurysms of the descending thoracic aorta can be caused by various etiologies. So, its abrupt rupture leads life-threatening state, it must be operated as soon as possible. Surgical treatment of the descending thoracic aortic aneurysm requires temporary cross-clamping of major artery. The obligatory occlusion of the descending thoracic aorta during management causes proximal arterial hypertension and distal arterial hypotension. The former may leads to left ventricular failure, or cerebrovascular accident, whereas the latter may leads to spinal cord ischemia or renal injury. Some have recommended insertion of temporary shunt around the occluded descending aorta to prevent above problems. Still others would favor expeditious operation employing simple aortic occlusion during the repair of the descending aorta. Recently we had experienced two cases of dissecting aneurysms of descending thoracic aorta which performed aortoplasty with Gore-Tex conduit under simple aortic occlusion. The one was 34-year-old female patient with traumatic dissecting aortic aneurysm [5 em X 5 cm] on the descending thoracic aorta distal to the origin of the left subclavian artery and the other was 58-year-old female patient with atherosclerotic dissecting descending thoracic aortic aneurysm [6 cmX7 cm] and diffuse abdominal aortic aneurysms [3X5 cm]. Both patients performed standard left posterolateral thoracotomy. After the aneurysmal sac was mobilized, occluding vascular clamps were placed on the transverse aorta proximal to the origin of the left subclavian artery, and on the distal descending aorta without adjuvant bypass procedures for 31 and 32 minutes, respectively, and the aneurysmal sac was repaired with 18 mm ringed Gore-Tex conduit graft. Both patients postoperative courses were uneventful.