• Title/Summary/Keyword: rupturing

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Development of Bag Rupturing Device with Octagonal Rotating Blade Drums for MSWs (생활계(生活系) 폐기물(廢棄物) 봉투(封套) 파봉을 위한 회전(回傳)칼날팔각(八角)드럼식(式) 파봉장치(裝置) 개발(開發)에 관(關)한 연구(硏究))

  • Lee, Byung-Sun;Na, Kyung-Duk;Han, Sang-Kuk;Choi, Woo-Zin;Park, Eun-Kyu;Kim, Dong-Ho
    • Resources Recycling
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    • v.18 no.5
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    • pp.63-71
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    • 2009
  • Recyclable wastes coming into material recovery facilities(MRFs) is mostly packed by plastic bag or sack bag. Bag rupturing device is essential to improve capacity and efficiency of MRFs. Bag opening works of MRFs is mostly done by numerous workers and shredder-type bag rupturing device. It often makes a problems; decreased capacity, shredded recyclables, worker safety by explosion and broken glasses, etc. In the present work, bag rupturing device with octagonal rotating blade drums has been developed to solve the existing problems and environment assessment is also performed during operation of the device. Capacity of the device was about 5.6 ton/hr at 8.2 rpm of drum revolution speed and 1.25 m/min of belt conveyor speed. It satisfied initial designed capacity(5.0 ton/hr) and max. capacity 8.8 ton/hr was achieved at 12.5 rpm of drum revolution speed and 1.50m/min of belt conveyor speed. Bag rupturing efficiencies on outer and inner bag were obtained at 100% and about 95.6% as average, respectively and original form of glass bottles in the bag was maintained without broken by about 96.5%. This result shows that the safety in hand sorting by the workers could be improved. As result of environmental assessment on the noise, vibration and particulates, the measured levels on noise, vibration and particulates show the below standard regulatory limits. It could be concluded that the problems of existing devices in MRFs could be solved by adopting the bag rupturing device with octagonal rotating blade drums in on-site operation.

Visualization of rupturing of rotating films (회전 원판 위 액막 유동 찢김 가시화)

  • Dong Ju Kim;Daegyoum Kim
    • Journal of the Korean Society of Visualization
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    • v.22 no.1
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    • pp.28-33
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    • 2024
  • We visualized the rupturing of liquid films flowing over a disk rotating with large angular velocity. A setup of high speed imaging for liquid flows on dark and reflective surfaces are suggested. From the result, rivulet structures are revealed to be strongly governed by three-dimensional surface structures developed in the film flow. Additionally, unique flow structures including the rivulet sliding and internal meandering are investigated. Generation mechanism of such structures are discussed in terms of the dynamic contact angle theory.

Rupturing Anterior Communicating Artery Aneurysm during Computed Tomography Angiography : Three-Dimensional Visualization of Bleeding into the Septum Pellucidum and the Lateral Ventricle

  • Kim, Ealmaan
    • Journal of Korean Neurosurgical Society
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    • v.55 no.6
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    • pp.357-361
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    • 2014
  • Computed tomography angiography (CTA) is commonly used in setting of subarachnoid hemorrhage, but imaging features of aneurysm rupturing taking place at the time of scanning has rarely been described. The author reports a case of actively rebleeding aneurysm of the anterior communicating artery with intraventricular extravasation on the hyperacute CTA imaging. The rebleeding route, not into the third ventricle but into the lateral ventricles, can be visualized by real-time three-dimensional CT pictures. The hemorrhage broke the septum pellucidum and the lamina rostralis rather than the lamina terminalis.

An approach to improve thickness distribution and corner filling of copper tubes during hydro-forming processes

  • GhorbaniMenghari, Hossein;Poor, Hamed Ziaei;Farzin, Mahmoud;Alves De Sousa, Ricardo J.
    • Structural Engineering and Mechanics
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    • v.50 no.4
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    • pp.563-573
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    • 2014
  • In hydroforming, the general technique employed to overcome the problem of die corner filling consist in increasing the maximum fluid pressure during the forming process. This technique, in other hand, leads to other difficulties such as thinning and rupturing of the final work piece. In this paper, a new technique has been suggested in order to produce a part with complete filled corners. In this approach, two moveable bushes have been used. So, the workpiece moves driven by both bushes simultaneously. In the first stage, system pressure increases until a maximum of 15 MPa, providing aninitial tube bulge. The results showed that the pressure in this stage have to be limited to 17 MPa to avoid fracture. In a second stage, bushes are moved keeping the constant initial pressure. The punches act simultaneously at the die extremities. Results show that the friction between part and die decreases during the forming process significantly. Also, by using this technique it is possible to produce a part with reasonable uniform thickness distribution. Other outcomes of applying this method are the lower pressures required to manufacture a workpiece with complete filled corners with no wrinkling.

The dynamic response and seismic damage of single-layer reticulated shells subjected to near-fault ground motions

  • Zhang, Ming;Parke, Gerry;Chang, Zhiwang
    • Earthquakes and Structures
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    • v.14 no.5
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    • pp.399-409
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    • 2018
  • The dynamic response and seismic damage of single-layer reticulated shells in the near field of a rupturing fault can be different from those in the far field due to the different characteristics in the ground motions. To investigate the effect, the dynamic response and seismic damage of this spatial structures subjected to two different ground motions were numerically studied by nonlinear dynamic response analysis. Firstly, twelve seismic waves with an apparent velocity pulse, including horizontal and vertical seismic waves, were selected to represent the near-fault ground motion characteristics. In contrast, twelve seismic records recorded at the same site from other or same events where the epicenter was far away from the site were employed as the far-fault ground motions. Secondly, the parametric modeling process of Kiewitt single-layer reticulated domes using the finite-element package ANSYS was described carefully. Thirdly, a nonlinear time-history response analysis was carried out for typical domes subjected to different earthquakes, followed by analyzing the dynamic response and seismic damage of this spatial structures under two different ground motions based on the maximum nodal displacements and Park-Ang index as well as dissipated energy. The results showed that this spatial structures in the near field of a rupturing fault exhibit a larger dynamic response and seismic damage than those obtained from far-fault ground motions. In addition, the results also showed that the frequency overlap between structures and ground motions has a significant influence on the dynamic response of the single-layer reticulated shells, the duration of the ground motions has little effects.

Surgical Correction of Bilateral Gastrocnemius Muscle Rupture and Its Prognosis in a Korean Native Calf

  • Gyuho Jeong;Younghye Ro;Kyunghyun Min;Woojae Choi;Ilsu Yoon;Hyoeun Noh;Danil Kim
    • Journal of Veterinary Clinics
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    • v.40 no.3
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    • pp.215-220
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    • 2023
  • A 3-month-old Korean native cattle (Hanwoo) calf with difficulty taking normal posture and an inability to rise was referred for a definite diagnosis and active treatment, including surgery. The calf had a history of an accident in which both hind limbs were trapped in a barn structure. After admission, a "rabbit leg" posture was observed, a typical sign of gastrocnemius muscle rupture, and both digits were knuckled downward like they were trying to grip the ground. This was considered to be a result of the superficial digital flexor not rupturing but only the gastrocnemius muscle rupturing. Physical examination revealed laceration of the metatarsus and firmness behind both stifle joints which were presumed to be the sites of gastrocnemius muscle rupture. Skeletal abnormalities, including fractures, were ruled out by radiography. Based on these findings, the patient was diagnosed with bilateral gastrocnemius muscle rupture, and surgery was performed to reconnect the head of the ruptured muscle. Because the rupture occurred perpendicular to the muscle direction, the locking loop technique, a method of suturing severed tendons, was used to reduce the tension. After surgery, the cast was used to prevent further injuries and promote voluntary rehabilitation. Follow-up was completed, with the calf showing normal posture and gait 112 days after surgery. This is the first case report in the Republic of Korea describing the successful diagnosis and treatment of bilateral gastrocnemius muscle rupture in a calf.

Characterization of Thin Liquid Films Using Molecular Dynamics Simulation

  • Lee, Jaeil;Park, Seungho;Ohmyoung Kwon;Park, Young-Ki;Lee, Joon-Sik
    • Journal of Mechanical Science and Technology
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    • v.16 no.11
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    • pp.1477-1484
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    • 2002
  • Various characteristics of a thin liquid film in its vapor-phase are investigated using the molecular dynamics technique. Local distributions of the temperature, density, normal and tangential pressure components, and stress are calculated for various film thicknesses and temperature levels. Distributions of local stresses change considerably with respect to film thicknesses, and interracial regions on both sides of the film start to overlap with each other as the film becomes thinner. Integration of the local stresses, i.e., the surface tension, however, does not vary much regardless of the interfacial overlap. The minimum thickness of a liquid film before rupturing is estimated with respect to the calculation domain sizes and is compared with a simple theoretical relation.

EXACT RIEMANN SOLVER FOR THE AIR-WATER TWO-PHASE SHOCK TUBE PROBLEMS (공기-물 이상매질 충격파관 문제에 대한 정확한 Riemann 해법)

  • Yeom, G.S.;Chang, K.S.
    • 한국전산유체공학회:학술대회논문집
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    • 2010.05a
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    • pp.365-367
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    • 2010
  • In this paper, we presented the exact Riemann solver for the air-water two-phase shock tube problems where the strength of the propagated sock wave is moderately weak. The shock tube has a diaphragm in the middle which separates water medium in the left and air medium in the right. By rupturing the diaphragm, various waves such as rarefaction wave, shock wave and contact discontinuity are propagated into water and air. Both fluids are treated as compressible, with the linearized equations of state. We used the isentropic relations for the air and water assuming a weak shock wave. We solved the shock tube problem considering a high pressure in the water and a low pressure in the air. The numerical results cleary showed a left-traveling rarefaction wave in the water, a right-traveling shock wave in the air, and the right-traveling material interface.

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EXACT RIEMANN SOLVERS FOR COMPRESSIBLE TWO-PHASE SHOCK TUBE PROBLEMS (압축성 이상(二相) 충격파관 문제에 대한 엄밀 리만해법)

  • Yeom, Geum-Su;Chang, Keun-Shik
    • Journal of computational fluids engineering
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    • v.15 no.3
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    • pp.73-80
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    • 2010
  • In this paper, we present the exact Riemann solver for the compressible liquid-gas two-phase shock tube problems. We hereby consider both isentropic and non-isentropic two-phase flows. The shock tube has a diaphragm in the mid-section which separates the liquid medium on the left and the gas medium on the right. By rupturing the diaphragm, various waves are observed on the phasic field variables such as pressure, density, temperature and void fraction in the form of rarefaction wave, shock wave and material interface (contact discontinuity). Both phases are treated as compressible fluids using the linearized equation of state or the stiffened-gas equation of state. We solve several shock tube problems made of a high/low pressure in the liquid and a low/high pressure in the gas. The wave propagations are well resolved by the exact Riemann solutions.

A study on the mechanism of stress corrosion cracking of stainless steel (스테인레스 강판의 응력부식균열 전파기구에 관한 연구)

  • 임우조;김영식
    • Journal of Advanced Marine Engineering and Technology
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    • v.9 no.2
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    • pp.153-158
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    • 1985
  • The dependence of the corrosion potential on the stress corrosion cracking of 304 austenitic stainless steel was inspected by using the specimen of constant displacement type under the environment of 42% $MgCl_2$ boiled solution. The relationship of the corrosion potential to the intermittent propagation behaviour in stress corrosion cracking was cleared. As the results, a possible model of stress corrosion cracking of 304 austenitic stainless steel in $MgCl_2$ boiled solution was presented on the basis of the Film Rupture Model. This model is specified by the following process. Rupturing of passive film at notch tip .rarw. Dissolution of metal ion and formation of tunnel .rarw. Initiation of microcrack .rarw. Propagation of main crack .rarw. Recreation of passive film at new crack surface.

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