• 한국지반공학회:학술대회논문집
• /
• 한국지반공학회 1988년도 학술세미나 강연집
• /
• pp.3-67
• /
• 1988

Model studies on the response of homgeneous earth embankment dams subjected to strike-slip fault movement have been penomed via centrifuge and finite element analysis. The centrifuge model tests have shown that crack development in earth embankment experiences two major patters: shear failure deep inside the embankment and tension failure near the surface. The shear rupture zone develops from the base level and propagates upward continuously in the transverse direction but allows no open leakage chnnel. The open tensile cracks develop near the surface of the embankment, but they disappear deep in the embankment. The functional relationship has been developed based on the results of the centrifuge model tests incorporating tile variables of amount of fault movement, embankment geometry, and crack propagation extent in earth des. This set of information can be used as a guide line to evaluate a "transient" safety of the duaged embankment subjected to strike-slip fault movement. The finite element analysis has supplemented the additional expluations on crack development behavior identified from the results of the centrifuge model tests. The bounding surface time-independent plasticity soil model was employed in the numerical analysis. Due to the assumption of continuum in the current version of the 3-D FEM code, the prediction of the soil structure response beyond the failure condition was not quantitatively accurate. However, the fundamental mechanism of crack development was qualitatively evaluated based on the stress analysis for the deformed soil elements of the damaged earth embankment. The tensile failure zone is identified when the minor principal stress of the deformed soil elements less than zero. The shear failure zone is identified when the stress state of the deformed soil elements is at the point where the critical state line intersects the bounding surface.g surface.

• Archives of Plastic Surgery
• /
• 제34권3호
• /
• pp.358-364
• /
• 2007

Purpose: A life-threatening hemorrhage resulting from a severe facial fracture is rare, but it needs a prompt and aggressive treatment. Especially, a massive oronasal bleeding combined with midfacial fracture which may result from the rupture of the internal maxillary artery. With the recent advances in the radiologic intervention, its use has increased for managing these life threatening case. We reviewed its usefulness with our experiences and literatures. Methods: A retrospective review was performed to determine the usefulness of the transcatheter arterial embolization in patients with panfacial trauma. If the vital signs were unstable, cardiopulmonary resuscitation was performed. Oronasal bleeding was controlled with nasal packing and electrocautery. All injured regions were studied by radiologic study including CT. Even after primary management, if the oronasal bleeding was persistent, radiologic intervention was performed 10 patients were treated with transcatheter arterial embolization and the bleeding focus controlled by embolization with polyvinyl alcohol and gelfoam. Results: After the intervention, the vital signs became stable and there were no complications from embolization in the follow-up for 6 months. Also patients could recover through appropriate operations. Conclusion: Transcatheter arterial embolization for maxillofacial injury has many advantages for both, the doctor and the patient. First, less pain is induced than a compression device or an operation, which is another way to treat oronasal bleeding. Second, it does not need general anesthesia. And through a single procedure not only we can know the accurate bleeding point, but we can also bleeding by embolization.

• 척추신경추나의학회지
• /
• 제5권2호
• /
• pp.151-158
• /
• 2010

Objective : SLAP is rupture of biceps brachii muscle tendon and it's origin, posterior side of superior labral to anterior glenoid fossa. Snapping and Pain, instability are its typical symptoms. SLAP is physical damage so surgeons use arthroscopy. In point of surgeons view, a conservative medicine is not effective for lesion of labrum. So In this article, we report a result of conservative treatment for the amatuer baseball player diagnosis with type 2 superior labral anterior posterior lesion. Methods : In this case, patient played amatuer baseball for 2 years, had diagnosis with type 2 Superior labral anterior posterior lesion by MRI after right shoulder Injury. OS recommened arthroscopy surgery. But he receive conservative Korean medicin treatment in Korean medicine hospital, including Atx, BV, herbal acupunture and rehabilitation excersise. Results : After 6 months, in the end of continuous conservative treatment and rehabilitation excersise, patient can play baseball normally, and felt a little pain. But In physical examination, he still has a some abnormal signs. Conclusion : A Conservative treatment for an amatuer baseball player diagnosis with SLAP type 2 was effective in restore of fuctional activities, but usefulness of this treatment needs more study.

• 철학연구
• /
• 제117권
• /
• pp.249-273
• /
• 2011

큰 틀에서 이 글은 철학적 성찰이 비쥬얼로 무대화되는 극장(劇場 movie theater)과 영화적 상상력이 개념으로 결정(結晶)되는 극장(極場 extreme field)에 관한 담론이다. 들뢰즈와 홍상수는 이 극장의 환유들이다. 이 환유들은 서로 긴밀하게 내통한다. 홍상수의 영화는 들뢰즈의 경험론을 이미지로 전시해주고, 들뢰즈의 유목론은 홍상수의 카메라를 이론으로 갈무리한다. 들뢰즈의 어휘로 말하자면 <돼지가 우물에 빠진 날>에서 <하하하>에 이르는 10편의 필모그래피를 채운 홍상수의 작품들은 어떤 국가장치로도 포획될 수 없는 전쟁기계들이다. 그것들은 영화관 내부에서만이 아니라 외부에까지 '되기'(becomming)의 생성을 확장해나간다. 우리의 관심사는 그 작품들의 '되기'를 계열선 위에 배치하는 게 아니라 탈주선 위로 방면하는 것이다. 차이, 되기, 놀기 등으로 유쾌하고 발랄하게 전개되는 홍상수의 영상들이 기존의 영화문법에 보내는 통렬한 야유를 들뢰즈 유목론의 맥락에서 조명해본다.

• Journal of Korean Neurosurgical Society
• /
• 제62권2호
• /
• pp.183-192
• /
• 2019

Objective : The objective of this study was to analyze patient-specific blood flow in ruptured aneurysms using obtained non-Newtonian viscosity and to observe associated hemodynamic features and morphological effects. Methods : Five patients with acute subarachnoid hemorrhage caused by ruptured posterior communicating artery aneurysms were included in the study. Patients' blood samples were measured immediately after enrollment. Computational fluid dynamics (CFD) was conducted to evaluate viscosity distributions and wall shear stress (WSS) distributions using a patient-specific geometric model and shear-thinning viscosity properties. Results : Substantial viscosity change was found at the dome of the aneurysms studied when applying non-Newtonian blood viscosity measured at peak-systole and end-diastole. The maximal WSS of the non-Newtonian model on an aneurysm at peak-systole was approximately 16% lower compared to Newtonian fluid, and most of the hemodynamic features of Newtonian flow at the aneurysms were higher, except for minimal WSS value. However, the differences between the Newtonian and non-Newtonian flow were not statistically significant. Rupture point of an aneurysm showed low WSS regardless of Newtonian or non-Newtonian CFD analyses. Conclusion : By using measured non-Newtonian viscosity and geometry on patient-specific CFD analysis, morphologic differences in hemodynamic features, such as changes in whole blood viscosity and WSS, were observed. Therefore, measured non-Newtonian viscosity might be possibly useful to obtain patient-specific hemodynamic and morphologic result.

• Advances in concrete construction
• /
• 제14권5호
• /
• pp.299-307
• /
• 2022

Cement-based matrixes have low tensile strength and negligible ductility. Adding fibres to these matrixes will improve their mechanical properties and make these composites suitable for structural applications. Post-cracking tensile strength of steel fibers-reinforced cementitious composite materials is directly related to the number of transverse fibers passing through the crack width and the pulling-out behavior of each of the fibers. Therefore, the exact recognition of the pullout behavior of single fibers is necessary to understand the uniaxial tensile and bending behavior of steel fiber-reinforced concrete. In this paper, an experimental study has been carried out on the pullout behavior of 3D (steel fibers with totally two hooks at both ends), 4D (steel fibers with a total of four hooks at both ends), and 5D (steel fibers with totally six hooks at both ends) in which the fibers have been located either perpendicular to the crack width or in an inclined manner. The pullout behavior of the mentioned steel fibers at an inclination angle of 0, 15, 30, 45, and 60 degrees and with embedded lengths of 10, 15, 20, 25, and 30 millimetres is studied in order to explore the simultaneous effect of the inclination angle of the fibers relative to the alongside loading and the embedded length of fibers on the pullout response in each case, including the maximal pullout force, the slip of the maximum point of pullout force, pullout energy, fiber rupture, and concrete matrix spalling. The results showed that the maximum pullout energy in 3D, 4D, and 5D steel fibers with different embedded lengths occurs at 0 to 30° inclination angles. In 5D fibers, maximum pullout energy occurs at a 30° angle with a 25 mm embedded length.

• Computers and Concrete
• /
• 제31권5호
• /
• pp.433-442
• /
• 2023

This study presents the visually observed behavior of fibers embedded in concrete samples that were subjected to a flexural bending test. Three types of fibers such as macro polypropylene, macro polyethylene, and the hybrid of steel and polyvinyl alcohol were mixed with cement by a designated mix ratio to prepare a total of nine specimens of each. The bending test was conducted by following ASTM C1609 with a net deflection of 2, 4, and 7 mm. The X-ray computed tomography (XCT) was carried out for 7 mm-deflection specimens. The original XCT images were post-processed to denoise the beam-hardening effect. Then, fiber, crack, and void were semi-manually segmented. The hybrid specimen showed the highest toughness compared to the other two types. Debonding based on 2D XCT sliced images was commonly observed for all three groups. The cement matrix near the crack surface often involved partially localized breakage in conjunction with debonding. The pullout was predominant for steel fibers that were partially slipped toward the crack. Crack bridging and rupture were not found presumably due to the image resolution and the level of energy dissipation for poly-fibers, while the XCT imaging was advantageous in evaluating the distribution and behavior of various fibers upon bending for fiber-reinforced concrete beam elements.

• Steel and Composite Structures
• /
• 제46권1호
• /
• pp.75-92
• /
• 2023

The novel composite cold-formed steel (CFS)/engineered cementitious composites (ECC) beams have been recently presented. The new composite section exhibited superior structural performance as a flexural member, benefiting from the lightweight thin-walled CFS sections with improved buckling and torsional properties due to the restraints provided by thinlayered ECC. This paper investigated the shear performance of the new composite CFS/ECC section. Twenty-eight simply supported beams, with a shear span-to-depth ratio of 1.0, were assembled back-to-back and tested under a 3-point loading scheme. Bare CFS, composite CFS/ECC utilising ECC with Polyethylene fibres (PE-ECC), composite CFS/MOR, and CFS/HSC utilising high-strength mortar (MOR) and high-strength concrete (HSC) as replacements for PE-ECC were compared. Different failure modes were observed in tests: shear buckling modes in bare CFS sections, contact shear buckling modes in composite CFS/MOR and CFS/HSC sections, and shear yielding or block shear rupture in composite CFS/ECC sections. As a result, composite CFS/ECC sections showed up to 96.0% improvement in shear capacities over bare CFS, 28.0% improvement over composite CFS/MOR and 13.0% over composite CFS/HSC sections, although MOR and HSC were with higher compressive strength than PE-ECC. Finally, shear strength prediction formulae are proposed for the new composite sections after considering the contributions from the CFS and ECC components.

• 한국염색가공학회지
• /
• 제35권4호
• /
• pp.246-255
• /
• 2023

In this study, we investigated for natural rubber foam to replace petrochemical-based neoprene foam. Experiments were conducted on vulcanization system and 2-step foaming process of natural rubber. The vulcanization system were EV(Efficient Vulcanization Cure), Semi-EV(Semi-Efficient Vulcanization Cure) and CV(Conventional Vulcanization Cure). In the 2-step foaming process, first molding temperature was 140℃, times were 15, 20, 25, and 30minutes, and the second molding temperature was 160℃, the times 5, 10, 15, and 20minutes. The cure and viscosity characterization were evaluated by oscillating disc rheometer (ODR) and mooney viscosmeter. Various mechanical characteristics, including hardness, tensile strength, elongation at the point of rupture, and tear strength, were quantified. Subsequently, an assessment of alterations in these mechanical attributes was conducted post-immersion in a NaCl solution. In addition degree of volume change was measured after immersing the NR foam in NaCl solution and the low-temperature permanent compression set was evaluated at 4℃. And expansion ratio and shrinkage ratio of NR foam were evaluated for 28 days. As a result the EV vulcanization system showed the least change in physical properties before and after salt water immersion, and the lowest shrinkage ratio for 28 days. In addition it was confirmed that the 2-step foaming optimum condition differed depending on the appropriate vulcanization condition.

• Nuclear Engineering and Technology
• /
• 제56권3호
• /
• pp.973-979
• /
• 2024

In the framework of the Generation IV research and development project, in which the French Commission of Alternative and Atomic Energies (CEA) is involved, a main objective for the design of Sodium-cooled Fast Reactor (SFR) is to meet the safety goals for severe accidents. Among the severe ones, the Unprotected Transient OverPower (UTOP) accidents can lead very quickly to a global melting of the core. UTOP accidents can be considered either as slow during a Control Rod Withdrawal (CRW) or as fast. The paper focuses on fast UTOP accidents, which occur in a few milliseconds, and three different scenarios are considered: rupture of the core support plate, uncontrolled passage of a gas bubble inside the core and core mechanical distortion such as a core flowering/compaction during an earthquake. Several levels and rates of reactivity insertions are also considered and the thermal-mechanical behavior of an ASTRID fuel pin from the ASTRID CFV core is simulated with the GERMINAL code. Two types of fuel pins are simulated, inner and outer core pins, and three different burn-up are considered. Moreover, the feedback from the CABRI programs on these type of transients is used in order to evaluate the failure mechanism in terms of kinetics of energy injection and fuel melting. The CABRI experiments complete the analysis made with GERMINAL calculations and have shown that three dominant mechanisms can be considered as responsible for pin failure or onset of pin degradation during ULOF/UTOP accident: molten cavity pressure loading, fuel-cladding mechanical interaction (FCMI) and fuel break-up. The study is one of the first step in fast UTOP accidents modelling with GERMINAL and it has shown that the code can already succeed in modelling these type of scenarios up to the sodium boiling point. The modeling of the radial propagation of the melting front, validated by comparison with CABRI tests, is already very efficient.