• 제목/요약/키워드: Face wall

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Prediction of the Environmental Conditions in Underground Tunnelling Spaces (地下터널 굴착作業場內 作業環境豫測)

  • Park, Hee-Bong
    • Tunnel and Underground Space
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    • v.2 no.1
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    • pp.116-122
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    • 1992
  • A comprehensive, nonsteady state, computer simulation program for the environmental conditions in advancing tunnels (the HEADSIM simulation program) is constructed and successfully validated with heat balance amongst all heat sources, and with mass conservation amongst various airflows including the leakage air from ducts, under timedependent variations of inlet air conditions. which include sudden, diurnal and seasonal changes. Heat conduction in the wall strata and face strata is simulated with most complicated boundary conditions using the finite difference method, and the climatic conditions in roadway sections which contain air ducts, booster fan, spray cooler, compressed air pipes, cold water pipes, return water pipes, machinery and broken rock are simulated taking into account the variations of face operation and the heat storage mechanism in the strata. The limitations of simulation time steps and roadway section lengths are defined according to the stability criteria satisfying the principles of thermodynamics. Variations of heat transfer coefficients, which are newly set, and those of wetness factors are taken into account according to the variations of other parameters and the stepwise advance of the face. Newly-derived formulae are used for computing the air duct leakage and the pressure inside of the duct. A new concept of an 'imaginary duct' is introduced to simulate the climatic conditions in tunnels during holiday periods, which directly affect conditions on subsequent working days under the consideration of natural convection. A subsidiary program (the WALLSIM simulation program) is made to compute the dimensionless tunnel surface temperatures and to compare the results with those from analytical approaches, and to demonstrate the stability, convergence and accuracy of the strata heat conduction simulation, adopting the finite difference method. The WALLSIM also has wide applications, including those for the computation of age coefficients.

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Various Applications of Deep Inferior Epigastric Artery Perforator Free Flap (심부하복벽천공지 유리피판의 다양한 임상적 적용)

  • Ahn, Hee Chang;Yang, Eun Zin;Kim, Chang Yeon;Lee, Jang Hyun
    • Archives of Plastic Surgery
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    • v.36 no.6
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    • pp.707-713
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    • 2009
  • Purpose: The deep inferior epigastric perforator(DIEP) free flap is well known as an ideal donor site for the breast reconstruction. The flap can provide huge amount of fat tissue for breast and buttock contour, while it is also very useful as a thin skin flap to reconstruct the upper and lower extremities. We used a DIEP free flap in various site reconstructions besides the breast and would like to reinsure the usefulness of this flap. Methods: Twenty nine consecutive patients who underwent DIEP free flap surgery from 2001 January to 2007 December were reviewed. The case constituted seven male patients and twenty two female patients. There were sixteen breast reconstructions, five face reconstructions, five lower extremity reconstructions, two upper extremity reconstructions, and one buttock contour reconstruction. All clinical data were based on the patient's medical records. Results: All DIEP free flaps survived without major complications. There was no hematoma, seroma, or partial necrosis. The donor sites were closed primarily with linear scar on lower abdomen. The thinnest part of flap was 0.7 cm in thickness. The size of the largest flap was $38{\times}13cm$. The flaps were used in various types of skin and adipose tissue, adipose tissue only, and skin only according to the requirement of recipient site. Conclusion: The DIEP free flap was enough to provide a thin and huge flap for both breast and extremity reconstructions. It was able to provide versatile designs with sufficient adipose tissue. So we use it for 3 - dimentional face and buttock contour reconstructions. The DIEP free flap is a valuable reconstructive donor for face, upper and lower extremity in addition to breast without compromising the integrity of abdominal wall.

Wave Reflection from Partialy Perforated Caisson Breakwater (부분 유공 케이슨 방파제로부터의 파의 반사)

  • Suh, Kyung-Doug
    • Journal of Korean Society of Coastal and Ocean Engineers
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    • v.8 no.3
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    • pp.221-230
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    • 1996
  • The Suh and Park's analytical model. originally developed to calculate wave reflection from a conventional fully perforated caisson breakwater, is applied to a partially perforated caisson breakwater by approximating the vertical wall of the lower part of the front face of the caisson as a very steep sloping wall. Also, in the model, the inertial resistance term at the perforated wall is modified by using the blockage coefficient proposed by Kakuno and Liu. The model is compared against the hydraulic experimental data reported by Park et al. in 1993. Both the experimental data and the analytical model results show that the influence of inertial resistance is important so that wave reflection becomes minimum when B/L. is approximately 0.2 (in which R : wave chamber width, and 1, : wave length inside the wave chamber), which is somewhat smaller than the theoretical value B/L, : 0.25 obtained by assuming that the influence of inertial resistance is negligible. It is also shown that the analytical model based on a linear wave theory tends to overpredict the reflection coefficient as the wave nonlinearity increases, thus the model is preferably to be used for ordinary waves of small steepness.

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Ultrasonographic Diagnosis of Subcutaneous Wooden Foreign Body (피하 조직에 발생한 나무 이물의 초음파 진단)

  • Choi, Ji-Hye;Keh, Seo-Yeon;Kim, Sung-Soo;Kim, Hye-Jin;Jang, Jae-Young;Choi, Hee-Yeon;Yoon, Jung-Hee
    • Journal of Veterinary Clinics
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    • v.28 no.1
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    • pp.163-172
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    • 2011
  • Subcutaneous foreign body causes recurrent problems such as chronic soft tissue swelling and discharge. Wooden foreign body is one of the most common foreign bodies found in subcutaneous region including face, interdigit, and thoracic or abdominal area. This report demonstrated three dogs with wooden foreign body located in subcutaneous region of thoracic wall, abdominal wall and upper eyelid, respectively. Three dogs showed prominent soft tissue swelling adjacent the foreign body. A sinus or drainage tract was developed in two of these dogs. Ultrasonography revealed that hyperechoic linear structure accompanied acoustic shadow in all dogs, and which was diagnosed as a subcutaneous foreign body. Anechoic or hyperechoic fluid and hypoechoic tissue circumscribed the foreign body. A subcutaneous foreign body in case 3 was removed by clamp under ultrasound-guide with sedation. Sinography was performed in case 1 and clarified that the wooden foreign body did not perforate the thoracic wall and there was no direct communication into thoracic cavity. Ultrasonography and sinography can be used to identify the subcutaneous foreign body and evaluate the inflammatory reaction and relationship between foreign body and adjacent structures.

Generalized Formula for Active Earth Pressure Estimation with Inclined Retaining Wall (점착력을 고려한 배면 경사 옹벽에서의 주동토압 산정 공식)

  • Kim, Woncheul;Hwang, Youngcheol
    • Journal of the Korean GEO-environmental Society
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    • v.9 no.5
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    • pp.71-81
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    • 2008
  • Active earth pressure formula, which can consider the effects of ground surface inclination, inclination of inside retaining wall face, wall friction, line load, uniform load, soil cohesion and adhesion, was derived based on the force equilibrium principle. In order to verify the accuracy of this proposed formula, the calculated active earth pressures by the proposed formula were compared with those of graphical solutions. Also, the active earth pressures determined by the proposed formula were compared with those by Coulomb's, Rankine's and Mazindrani's solution under specific conditions. The results matched quite well not only with the graphical solutions but also with those by three other methods. Also, the trend of active earth pressures by the proposed formula were corresponded with results of experimental study by Fang, et al. It can be concluded that this generalized formula not only can overcome the limitations of Rankine's, Coulomb's and Mazindrani's active earth pressure formula but also can consider the external loading conditions.

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A Study on the Use of Police Force in the Public Assembly: Focused on the Vehicle-wall-blocking and water cannon (집회현장에서의 경찰의 물리력 사용현황과 개선방안: 차벽과 물포 사용을 중심으로)

  • Hwang, Mun-Gyu
    • Korean Security Journal
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    • no.50
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    • pp.307-337
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    • 2017
  • The freedom of assembly is the fundamental freedoms guaranteed by the Constitution. However, as far as our reality is concerned, the freedom of assembly is guaranteed only when it is under the control of the police, and otherwise it is perceived as an object to be suppressed. Police say even that they will not tolerate even a small illegal law while referring to the "broken window theory". Therefore, regardless of the peaceful nature of the rally, it is too obsessed with 'compliance'. This attitude is causing the citizens who participated in the assembly to be put to the object to be suppressed. This paper analyzes the requirements and current status of police force, focusing on the vehicle-wall-blocking and water cannon as a means of using the police force, which is a recent problem, and suggests ways to improve it. First of all, the installation of the wall cuts off the essential communication function of the assembly by separating the meeting place from the object of protest. Thus, despite the warning for prevention in the face of illegal acts, other than installing a barrier, it should be allowed only in the 'urgent case where there is a risk of causing damage to the life, body or property of the person'. Without this urgency, the vehicle-wall-blocking should not be allowed to be proactive as well as preventive. Secondly, the water cannon is a police force that is likely to harm people's life and body. Therefore, aiming shots, which could pose a significant risk to the human body, should in principle be prohibited. However, considering its risk, it should be supplementary used only when there is no other alternative, only when the direct risk to the legal interest of the other person or the order of public well-being is 'obvious'. In addition, as for the use standard of such a thing, it is necessary to be specified by law.

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A Study on the Evaluation of Necessity for the Support in Case of Excavartion of the Transport Drift at Danyang Site (단양지역의 운방갱도 굴착시 갱도 지보의 필요성 판정에 관한 연구)

  • 이종욱;조만섭;김일중;김영석
    • Tunnel and Underground Space
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    • v.3 no.1
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    • pp.54-62
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    • 1993
  • In order to evaluate the necessity for the support during the excavation of the transport drift and use the data for design applications, laboratory testings of mechanical properties of rock samples and engineering rock mass classifications on this study site were performed. The values of RMR and Q-system are 68 and 11.8, respectively. Since these results were evaluated as good, this rock mass were determined to be unsupported. Full face excavation method was determined to be suitable for excavating this drift. In case of excavation, smooth blasting techniques must be carried out at the wall rock and the crown. However, considering the blast vibration etc. that have an effect on the surrounding rock mass, approximately less than 9kg of explosive charges per blast should be maintained.

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Short term unsteady wind loading on a low-rise building

  • Sterling, M.;Baker, C.J.;Hoxey, R.P.
    • Wind and Structures
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    • v.6 no.5
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    • pp.403-418
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    • 2003
  • This paper presents an extensive analysis of the short term, unsteady wind loading on a low-rise building. The building is located in a rural environment and only the specific situation of wind flow orthogonal to the long face of the structure is considered. The data is analysed using conventional analysis and less traditional methods such as conditional sampling and wavelet analysis. The nature of the flow field over the building is found to be highly unsteady and complex. Fluctuating pressures on the windward wall are shown to a large extent to be caused by the fluctuations in the upstream flow, whereas extreme pressures on the roof are as a result of high intensity small scale flow structures. On the roof of the building a significant amount of energy is shown to exist at frequencies above 1 Hz.

Zygomaticomaxillary complex fracture after two-jaw surgery

  • Park, Joseph Kyu-hyung;Kim, Sang Wha
    • Archives of Craniofacial Surgery
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    • v.21 no.5
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    • pp.301-304
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    • 2020
  • Orthognathic surgeries often utilize rigid fixation for stabilization of the osteotomy site. The longterm fate of rigid fixations is still under investigation, and whether they should be routinely removed is under debate despite their low complication rates. Here, we report a case where a 26-year-old man suffered high-velocity trauma to his face 7 years after a two-jaw surgery. Computed tomography examination revealed a zygomaticomaxillary complex fracture, and open reduction and internal fixation was performed along with anterior maxillary wall reconstruction using absorbable mesh. Intraoperative examination revealed a broken L-shaped titanium plate near the fracture site with multiple bony fragments near each titanium screw. The rigid titanium system may have caused comminution of the fracture pattern, worsening the severity of the fracture.

The Weatherability of Non-woven Geotextiles Used in Reinforced Earth Wall (보강토옹벽에 적용되는 지오텍스타일의 내후성)

  • 유중조;김영윤;전한용
    • Proceedings of the Korean Geotechical Society Conference
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    • 2001.03a
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    • pp.419-424
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    • 2001
  • In the KOESWall system, non-woven geotextiles are placed at the face of reinforced earth until the facing blocks are built up. And when this system is used as temporary structure, geotextiles facings are exposed to sunlight during service lifetime. During these periods, degradation of nonwoven geotextiles are occurred by UV light. So the UV-resistance of nonwoven geotextiles must be assessed correctly, in considering of the site conditions. In this study, laboratory test and the field test have been performed to evaluate the UV resistance of non-woven geotextiles used in KOESWall system and the results are expressed in terms of tensile characteristics & SEM photographs.

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