• Title/Summary/Keyword: side-wall

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Stability Analysis of Concrete Plugs Installed in Pilot Tunnels for the Storage of Compressed Air (압축공기 저장용 파일롯 터널에 설치된 콘크리트 플러그의 안정성 해석)

  • Lee, Youn-Kyou;Song, Won-Kyoung;Park, Chul-Whan;Choi, Byung-Hee
    • Tunnel and Underground Space
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    • v.20 no.6
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    • pp.446-454
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    • 2010
  • CAES-G/T (Compressed Air Energy Storage - Gas Turbine) power generation is a likely option for the buffer facility stabilizing the fluctuation of the renewable powers, such as wind and solar powers. Considering the geological conditions, the underground CAES facility is most probable if the CAES-G/T generation is planed in Korea. In this kind of facility, a concrete plug is installed to seal the compressed air in the container, so that the selection of the shape and dimension of concrete plug could be a critical design factor. The stability evaluation of two types of plug was carried out by investigating the distribution of the factor of safety in the plugs and the distribution of contact pressure over the contact surface. The analysis result shows that the taper-shaped plug is more structurally stable than the wedge-shaped plug for the given geological condition. Possible separation of the rock-concrete interface around the spring line of the wedge-shaped plug is anticipated, which means the possible leakage of compressed air through the side wall and also means the poor mobilization of frictional resistance on that area.

A Tunnel Mock-up Test and Numerical Analysis on Steel Fiber Reinforced Shotcrete (강섬유 보강 숏크리트의 터널모형실험 및 수치해석적 검증)

  • You, Kwang-Ho;Jung, Ji-Sung;Park, Yeon-Jun
    • Tunnel and Underground Space
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    • v.18 no.2
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    • pp.107-117
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    • 2008
  • In this study, the failure and deformation characteristics of steel fiber reinforced shotcrete (SFRS) which is a primary tunnel support was investigated to find out ground-support mutual behavior. To this end, a mock-up of a tunnel was made and experimented with the conditions of lateral earth pressure coefficient 0.5 and 1.0. During the tests, 11 hydraulic cylinders were used for loading. for better simulation of the lateral earth pressure effect, these cylinders were controlled separately by two groups; crown and side wall. Meanwhile, the deformation of shotcrete was measured by 11 LVDTs. Backfill material was also used fur better load transfer from hydraulic cylinders to shotcrete. For the validation of the mock-up test results, 3D numerical analysis is carried out. To do numerical analysis under the same condition as a mock-up test, the load history curve which was obtained during the test was tried to be simulated using an individual FISH routine in the numerical analysis.

Analysis of the Effect on the Process Parameters for the Thin Ceramic Plate in the Ceramic Injection Molding (판상제품의 세라믹 사출 시 공정변수 영향 분석)

  • Kim, Jinho;Hong, Seokmoo;Hwang, Jihoon;Lee, Jongchan;Kim, Naksoo
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.15 no.5
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    • pp.2587-2593
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    • 2014
  • Ceramic Injection Molding (CIM) is one of wide used processes in industry field and the applications are gradually being expanded to parts of medical and electric devices. In this study, the CIM process were analyzed with FEM and process parameters were studied and analyzed the effect on product quality. The shape of simple flat plate was compared to the shapes with the hole, with the round corner portion or with the side wall portion. If there are holes then the hole around the uneven density distribution and the defects such as weld lines could be occurred. The Large radius of the corners of the product give good formability and fluidity. Not only the shape parameters of product but also the process parameters during CIM are studied. The simulation results showed that the process parameters of temperature, initial fractions and velocity are important design parameters to improve the quality of products.

A Study on the Influence of Behavior of Underground Cavern to Cavern Size and Joint Orientation (공동 규모와 절리 방향성이 지하공동의 거동에 미치는 영향에 대한 연구)

  • Kim, Sang-Hwan;Shin, Beom-Seok
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.14 no.1
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    • pp.84-92
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    • 2010
  • This paper presents the influence of the underground structure (such as cavern and tunnels) behavior according to the rock joint orientation and underground cavern size. In order to perform this research, numerical and experimental studies are carried out. Stress aspect was assessed by quantitative according two kind of factor. In the experimental study, the laboratory model tests are performed in the several ground conditions with different underground cavern size. The results obtained from the model tests are also verified and evaluated using the numerical analysis. Due to the underground cavern, it is found from this study that the stresses developed in archcrown, side wall of underground are increased with increasing the underground cavern size. It is also investigated that the rock joint direction is one of main influence factor as risk factor, to maintain the underground cavern stability. It may be expected that this research will provide the very useful information to evaluate the underground cavern stability.

Delayed Orbital Hemorrhage around Alloplastic Implants after Blowout Fracture Reduction

  • Ryu, Yong Ah;Park, Jae Beom;Kyung, Hyun Woo;Song, Seung Han;Kang, Nak Heon
    • Archives of Craniofacial Surgery
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    • v.16 no.1
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    • pp.35-38
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    • 2015
  • Alloplastic implants have been used to repair orbital wall fractures in most cases. Orbital hemorrhage is a rare complication of these implants and has been reported rarely in Korea. The purpose of this article is to report a late complication case focusing on their etiology and management. A 20-year-old male patient underwent open reduction with Medpor (porous polyethylene) insertion for bilateral orbital floor fractures. The initial symptom occurred with proptosis in the right side as well as vertical dystopia, which had started 4 days earlier, 8 months after surgery. Any trauma history after the surgery was not present. We performed an exploration and removal of hematoma with Medpor titanium meshed alloplastic implant. A case of delayed orbital hematoma following alloplastic implant insertion was identified. It occurred within the pseudocapsule of the implant. One week after surgery, overall symptoms improved successfully, and no complications were reported during the 11-month follow-up period. Although rare, orbital hemorrhage is a potential complication of alloplastic orbital floor implants, which may present many years after surgery. As in the case presented, delayed hematoma should be included in the differential diagnosis of late proptosis or orbital dystopia.

The effect of ankle Kinesio taping on range of motion and agility during exercise in university students

  • Eom, Se Young;Lee, Won Jun;Lee, Jae Il;Lee, Eun Hee;Lee, Hye Young;Chung, Eun Jung
    • Physical Therapy Rehabilitation Science
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    • v.3 no.1
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    • pp.63-68
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    • 2014
  • Objective: The purpose of this study was to examine the effects of ankle Kinesio taping on range of motion and agility during exercise in university students. Design: Cross-sectional study. Methods: Thirty subjects were randomly allocated to two groups: taping group (n=15) and non-taping group (n=15). All groups underwent the same exercise program including stretching for 30 minutes. The exercise program proceeded in the following order: five minutes of stretching, a 20-minutes exercise program, and additional five minutes of stretching. Of the eight exercise methods suggested by Purcell et al, seven were chosen (lateral shuffle, forward and backward running, agility ladder, figure-of-8, forward jogging while jumping over cones, wall jumps and zigzags); 9090 cuts with lateral shuffle were omitted. The range of motion of ankle dorsiflexion and plantarflexion was measured using the goniometer. Agility was measured using the side hop test. Results: For ankle range of motion, the taping group showed significant differences in dorsiflexion and plantarflexion on both sides (p<0.05). The non-taping group showed significant differences only in left plantarflexion (p<0.05). There was a significant difference in dorsiflexion on both sides between the taping group and the non-taping group (p<0.05). All groups showed significant differences in agility on the left and right ankle (p<0.05). There was a significant difference in left ankles between the taping group and the non-taping group (p<0.05). Conclusions: Kinesio taping increased range of motion and agility during exercise in university students. Additional research on Kinesio taping for improving range of motion and agility is needed.

ADPI Characteristics of Line Diffuser in a Room with Perimetric Heating Load (측벽 부하가 존재하는 공간에 설치된 라인 디퓨져의 ADPI 특성에 관한 연구)

  • Cho Young-Jin;Kang Seok-Youn;Moon Jong -Sun;Lee Jae-Heon
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.16 no.12
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    • pp.1204-1211
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    • 2004
  • It is difficult to apply a conventional selection guide for diffusers when the diffuser is installed in a perimeter zone, because the air diffusion performance index (ADPI) vs. throw/length (T/L) ratio curve listed in conventional guide does not consider the perimetric heating load through the walls. The objective of this study is to evaluate the effect of the perimetric heating load on the ADPI and propose a selection guide for a proper line diffuser when perimetric heating load exists. The velocity and temperature distributions and the ADPI values are obtained numerically with various heat load ratios and air flow rates. The velocity and temperature distributions and the ADPI values are analyzed by CFD in case of various heat load ratios and air flow rates. Also, ADPI was calculated by those results. The ADPI values by numerical results are compared with an existing experimental data to verify the method for the evaluation of ADPI proposed in a present study. In case of a line diffuser installed at the high side wall, the ADPI decreases according to the increases of the flow rate on every heat load ratio of the present study except 0.75. The ADPI vs. T/L ratio curves have been proposed for the heat load ratios of 0.25, 0.5, 0.75 to guarantee the comport thermal environment when diffusers are installed in perimeter zone.

Transonic buffet alleviation on 3D wings: wind tunnel tests and closed-loop control investigations

  • Lepage, Arnaud;Dandois, Julien;Geeraert, Arnaud;Molton, Pascal;Ternoy, Frederic;Dor, Jean Bernard;Coustols, Eric
    • Advances in aircraft and spacecraft science
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    • v.4 no.2
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    • pp.145-167
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    • 2017
  • The presented paper gives an overview of several projects addressing the experimental characterization and control of the buffet phenomenon on 3D turbulent wings in transonic flow conditions. This aerodynamic instability induces strong wall pressure fluctuations and therefore limits flight domain. Consequently, to enlarge the latter but also to provide more flexibility during the design phase, it is interesting to try to delay the buffet onset. This paper summarizes the main investigations leading to the achievement of open and closed-loop buffet control and its experimental demonstration. Several wind tunnel tests campaigns, performed on a 3D half wing/fuselage body, enabled to characterize the buffet aerodynamic instability and to study the efficiency of innovative fluidic control devices designed and manufactured by ONERA. The analysis of the open-loop databases demonstrated the effects on the usual buffet characteristics, especially on the shock location and the separation areas on the wing suction side. Using these results, a closed-loop control methodology based on a quasi-steady approach was defined and several architectures were tested for various parameters such as the input signal, the objective function, the tuning of the feedback gain. All closed-loop methods were implemented on a dSPACE device able to estimate in real time the fluidic actuators command calculated mainly from the unsteady pressure sensors data. The efficiency of delaying the buffet onset or limiting its effects was demonstrated using the quasi-steady closed-loop approach and tested in both research and industrial wind tunnel environments.

Indoor distribution characteristics of airborne bacteria in pig buildings as influenced by season and housing type

  • Kim, Ki Youn;Ko, Han Jong
    • Asian-Australasian Journal of Animal Sciences
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    • v.32 no.5
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    • pp.742-747
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    • 2019
  • Objective: A concentration of airborne bacteria generated from swine houses is recognized to be relatively higher than other work places and it is essential to optimally manage it to prevent farmers' respiratory diseases. This study was conducted to assess the distribution characteristics of airborne bacteria in swine houses located at South Korea. Methods: A total 27 pig buildings of the enclosed type operated with mechanical ventilation system by a side wall fan and deep-pit manure system with slats were surveyed. Air samples were collected at 1.0 m above the middle floor in pig housing room. A six-stage viable particulate cascade impactor was used to identify the distribution of the sizes of particles in diameter. Results: Seasonal mean levels of airborne bacteria in the housing rooms of gestation/farrowing pigs, nursery pigs and growing/fattening pigs were 3,428(±1,244±1,244) colony forming unit (cfu)/m3(cfu)/m3, 8,325(±3,209)cfu/m8,325(±3,209)cfu/m, and 13,254(±6,108)cfu/m313,254(±6,108)cfu/m3 for spring; 9,824(±2,157)cfu/m39,824(±2,157)cfu/m3, 18,254(±5,166)cfu/m318,254(±5,166)cfu/m3, and 24,088(±9,274)cfu/m324,088(±9,274)cfu/m3 for summer; 1,707(±957)cfu/m31,707(±957)cfu/m3, 4,258(±1,438)cfu/m34,258(±1,438)cfu/m3, and 8,254(±2,416)cfu/m38,254(±2,416)cfu/m3 for autumn; and 2,322(±1,352)cfu/m32,322(±1,352)cfu/m3, 6,124(±1,527)cfu/m36,124(±1,527)cfu/m3 and 12,470(±4,869)cfu/m312,470(±4,869)cfu/m3 for winter, respectively. Conclusion: Concentrations of airborne bacteria according to pig housing type were highest in growing/fattening housing room followed by nursery housing room and gestation/farrowing housing room. In terms of seasonal aspect, the pig building showed the highest levels of airborne bacteria in summer followed by spring, winter and autumn. The respirable airborne bacteria which are ranged between 0.6 and 4.7μm4.7μm accounted for approximately 60% compared to total airborne bacteria regardless of pig housing type.

A study on weight reduction of bracket using CAE program (CAE 프로그램을 이용한 브래킷 경량화에 관한 연구)

  • Kang, Hyung-Suk;Han, Bong-Suk;Han, Yu-Jin;Choi, Doo-Sun;Kim, Tae-Min;Shin, Bong-Cheol;Song, Ki-Hyeok
    • Design & Manufacturing
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    • v.12 no.3
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    • pp.25-30
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    • 2018
  • Recently The automotive industry is trying to increase the energy efficiency by reducing the weight of the car body and engine components as a way to achieve high energy efficiency. In particular, the reduction of the weight of the vehicle through the weight reduction of the vehicle body has the advantage that the fuel consumption and the output can be improved. But at the same time, there is the disadvantage that the strength becomes weak due to the reduction of the material thickness. Therefore, in order to overcome these disadvantages, materials with high strength according to the unit thickness have been actively developed, and researches for applying them have also been increasing. In this study, we will investigate the application of cold rolled steel sheet, which is a lightweight material, to a horn bracket that secures a installed in an automobile engine room. The horn bracket secures the horn on the car engine and is bolted to the outer wall of the engine. The momentum is acted on the bracket due to the distance between the bolt fastening part and the car horn installed on the bracket end side. Therefore, the body part of the bracket is more likely to be destroyed by the influence of the continuous stress. In this paper, design optimization for weight reduction and strength enhancement was performed to solve this problem, and possibility of applying the rolled steel sheet material as lightweight material by tensile test and fabrication was confirmed.