• Title/Summary/Keyword: collapse rate

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Surgical outcomes in dogs with tracheal collapse treated with a novel cross-and-hook braided endoluminal stent

  • Uemura, Akiko;Ozai, Yusuke;Hamabe, Lina;Yoshida, Tomohiko;Tanaka, Ryou
    • Journal of Veterinary Science
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    • v.23 no.3
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    • pp.46.1-46.8
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    • 2022
  • Background: Stenting is an effective treatment option for tracheal collapse in dogs. Cross-braided tracheal stents are currently the norm in veterinary medicine, but cross-and-hook braided stents have recently been adopted in human medicine. We examined whether stents manufactured using this novel braiding technique provided additional advantages for the treatment of tracheal collapse in dogs. Objectives: To evaluate the outcomes of cross-and-hook braided stent implantation in the treatment of tracheal collapse in dogs. Methods: The medical records of 22 client-owned dogs that underwent luminal placement of cross-and-hook braided Fauna Stents for the treatment of tracheal collapse between January 2018 and July 2021 were examined and data on canine signalment, clinical signs, diagnostic test results, surgical outcomes, and postoperative complications were retrieved and analyzed statistically. Results: Twenty-six stents were surgically implanted, with 20 dogs (90.9%) receiving one stent and the remaining two (9.1%) receiving two or more stents. All dogs survived the procedure. The median survival time at a median follow-up of 990 days was 879 days. At the final follow-up examination, loss or mild improvement of cough was observed in all dogs. Conclusions: Compared with conventional lumen stents, the cross-and-hook braided Fauna Stent offered a higher survival rate and improved clinical symptoms in all patients. The results of this study suggest that the Fauna Stent may be a promising treatment option for dogs with tracheal collapse.

3D Finite Element Analysis of Fault Displacements in the Nobi Fault Zone, Japan

  • Choi, Young-Mook;Kim, Woo-Seok;Lee, Chul-Goo;Kim, Chang-Yong;Seo, Yong-Seok
    • The Journal of Engineering Geology
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    • v.24 no.3
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    • pp.323-332
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    • 2014
  • The Nobi fault zone, which generated the 1891 Nobi Earthquake (M8.0), includes five or six faults distributed in and around Gifu and Aichi prefectures, Japan. Because large cities are located near the fault zone (e.g., Gifu and Nagoya), and because the zone will likely be reactivated in the future, relatively thorough surveys have been conducted on the 1891 Nobi earthquake event, examining the fault geometry, house collapse rate, and the magnitude and distribution of earthquake intensity and fault displacement. In this study, we calculated the earthquake slip along faults in the Nobi fault zone by applying a 3D numerical analysis. The analysis shows that a zone with slip displacements of up to 100 mm included all areas with house collapse rates of 100%. In addition, the maximum vertical displacement was approximately ${\pm}1700mm$, which is in agreement with the ${\pm}1400mm$ or greater vertical displacements obtained in previous studies. The analysis yielded a fault zone with slip displacements of > 30 mm that is coincident with areas in which house collapse rates were 60% of more. The analysis shows that the regional slip sense was coincident with areas of uplift and subsidence caused by the Nobi earthquake.

The Estimated Drying Schedules of Larix leptolepis and Pinus koraiensis (낙엽송과 잣나무재의 추정건조(推定乾燥)스케쥴)

  • Park, Jong-Su;Kim, Su-Chang
    • Journal of Forest and Environmental Science
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    • v.11 no.1
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    • pp.50-60
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    • 1995
  • This study was carried out to estimate drying schedules of Larix Leptolepis and Pinus koraiensis by oven-drying at $100^{\circ}C$ which aimed to elucidate the characteristics such as current moisture content, drying process. initial check, collapse, internal check and drying rate during drying following each board thickness (2, 3. 4, 5, 6cm). the results were summerized as follows; Current moisture content of each board showed a rapid drying curve with the decrease of board thickness. At 20% moisture content, the drying rate of Larix leptolepis was higher than that of Pinus koraiensis and the drying rate of boards was lower with the increase of board thickness. From the estimated drying schedules. the initial conditions of drying of Larix leptolepis had to be milder than those of Pinus koraiensis and the boards thickness of 5cm, 6cm had to be most mild conditions.

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Explosive loading of multi storey RC buildings: Dynamic response and progressive collapse

  • Weerheijm, J.;Mediavilla, J.;van Doormaal, J.C.A.M.
    • Structural Engineering and Mechanics
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    • v.32 no.2
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    • pp.193-212
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    • 2009
  • The resilience of a city confronted with a terrorist bomb attack is the background of the paper. The resilience strongly depends on vital infrastructure and the physical protection of people. The protection buildings provide in case of an external explosion is one of the important elements in safety assessment. Besides the aspect of protection, buildings facilitate and enable many functions, e.g., offices, data storage, -handling and -transfer, energy supply, banks, shopping malls etc. When a building is damaged, the loss of functions is directly related to the location, amount of damage and the damage level. At TNO Defence, Security and Safety methods are developed to quantify the resilience of city infrastructure systems (Weerheijm et al. 2007b). In this framework, the dynamic response, damage levels and residual bearing capacity of multi-storey RC buildings is studied. The current paper addresses the aspects of dynamic response and progressive collapse, as well as the proposed method to relate the structural damage to a volume-damage parameter, which can be linked to the loss of functionality. After a general introduction to the research programme and progressive collapse, the study of the dynamic response and damage due to blast loading for a single RC element is described. Shock tube experiments on plates are used as a reference to study the possibilities of engineering methods and an explicit finite element code to quantify the response and residual bearing capacity. Next the dynamic response and progressive collapse of a multi storey RC building is studied numerically, using a number of models. Conclusions are drawn on the ability to predict initial blast damage and progressive collapse. Finally the link between the structural damage of a building and its loss of functionality is described, which is essential input for the envisaged method to quantify the resilience of city infrastructure.

Quantitative Analysis on the Damage of the Austenitic Stainless Steel under the Simultaneous Cavitation Bubble and Solid Particle Collapses (오스테나이트계 304 스테인리스강의 케비테이션 기포 및 고체 입자 동시 충격 손상의 정량적 고찰)

  • Hong, Sung-Mo;Park, Jin-Ju;Lee, Min-Ku;Rhee, Chang-Kyu
    • Korean Journal of Metals and Materials
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    • v.48 no.10
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    • pp.893-900
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    • 2010
  • In the present work, the impact loads and their effects on the surface damage under the simultaneous cavitation bubble and solid particle collapses in the sea water have been quantitatively investigated for the austenitic 304 stainless steel by using a vibratory cavitation test device. To do this, angular $SiO_2$ solid particles with an average size of $150{\mu}m$ were dispersed into the test liquid, and the measured impact amplitudes were converted into the impact loads by a steel ball drop test. The maximum impact load was determined to be 28.2 N in the absence of solid particles, but increased to 33.7 N in the presence of solid particles. In addition, the critical impact loads, $L_{crit}$, required to generate pits with sizes greater than $3{\mu}m$ were measured to be 19.6 N and 16.6 N, respectively, for the cavitation bubble collapse and solid particle collapse. As a result of the cavitation erosion test, the incubation time and erosion rate were 1.2 times lower and 1.5 times higher, respectively, by a solid particle collapse compared to those only by the cavitation bubble collapse, indicating a drastic decrease in a resistance to cavitation erosion by the solid particle collapse.

The Effect of Massive Neutrinos on the Merging Rates of the First Objects

  • Song, Hyun-Mi;Lee, Joung-Hun
    • The Bulletin of The Korean Astronomical Society
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    • v.35 no.2
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    • pp.44-44
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    • 2010
  • We study the effect of massive neutrinos on the evolution of the early mini-halos ($M\sim10^6h^{-1}M{\odot}at$ z~20) where the first stars may have formed. In the framework of the extended Press-Schechter formalism, we evaluate analytically the rates of merging of the mini-halos into zero-dimensional larger halos and one-dimensional mini-filaments. It is shown that the halo-to-filament merging rate increases with the neutrino mass fraction $f_v$ while the halo-to-halo merging rate decreases. Comparing the cases of $f_v$=0 and 0.10, the halo-to-filament merging rate for $f_v$=0.10 is 3 times larger than the other. The distribution of the epochs of the longest-axis collapse of these first filaments is also derived and found to reach a sharp maximum at z~8-9. Once the first mini-filaments form, they would provide bridges along which the matter and gas more rapidly accrete onto the constituent halos, causing the early formation of the first galaxies and rapid growth of their central blackholes. Furthermore, the longest axis collapse of these first mini-filaments would spur the supermassive blackholes to power the ultra-luminous high-z quasars.

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Sub-mm variability of a YSO (EC53) in Serpens main region : JCMT Transient survey

  • Yoo, Hyunju;Lee, Jeong-Eun;Johnstone, Doug;Mairs, Steve;Herczeg, Gregory
    • The Bulletin of The Korean Astronomical Society
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    • v.42 no.1
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    • pp.39.2-39.2
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    • 2017
  • Stars form through the gravitational collapse of molecular clouds. However, the rate at which a star gains most of its mass and the physics that drives the main phase of stellar growth is still unclear. The typical luminosity of observed protostars is smaller than what expected from the Shu's inside-out collapse model, which predicts a constant mass accretion rate. The episodic accretion model has been suggested as a solution of this luminosity problem. The JCMT Transient survey is a long term monitoring program using JCMT/SCUBA-2 to detect accretion variability of protostars in the eight nearby star-forming regions. Recently, we found a rise of the 850 micron flux at a clump in the Serpens main region at the rate of ~17% relative to the mean flux over previous observations. The submm clump is associated with a class I protostar, EC53, which has been reported as a binary system with a periodic variability. In this talk, we will provide a brief overview of the JCMT Transient Survey project, present the detection of the variable source, and discuss about follow-up observations.

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NUMERICAL SIMULATION OF CONVEX AND CONCAVE TUBES WITH CONSIDERATION OF STRAIN RATE SENSITIVITY

  • Ye, B.W.;Oh, S.;Cho, Y.B.;Sin, H.C.
    • International Journal of Automotive Technology
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    • v.8 no.2
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    • pp.193-201
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    • 2007
  • The present paper deals with the application of the explicit finite element code, PAM-CRASH, to simulate the crash behavior of steel thin-walled tubes with various cross-sections subjected to axial loading. An isotropic elastic, linear strain-hardening material model was used in the finite element analysis and the strain-rate sensitivity of mild steel was modeled by using the Cowper-Symonds constitutive equation with modified coefficients. The modified coefficients were applied in numerical collapse simulations of 11 types of thin-walled polygon tubes: 7 convex polygon tubes and 4 concave polygon tubes. The results show that the thin hexagonal tube and the thick octagonal tube showed relatively good performance within the convex polygon tubes. The crush strengths of the hexagonal and octagonal tubes increased by about 20% and 25% from the crush strength of the square tube, respectively. Among the concave tubes, the I-type tube showed the best performance. Its crush strength was about 50% higher than the crush strength of the square tube.

A Study on Development of Reaction Rate Equation for Reactive Flow Simulation in Energetic Materials (고에너지 물질의 연소반응 해석을 위한 반응속도식 개발 및 정의에 관한 연구)

  • Kim, Bo-Hoon;Yoh, Jai-Ick
    • Journal of the Korean Society of Propulsion Engineers
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    • v.16 no.5
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    • pp.47-57
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    • 2012
  • A modified ignition and growth(I&G) model which is necessary to simulate the combustion phenomena of energetic materials and an analytical model determining the unknown parameters of the reaction rate equation are proposed. The modified I&G model sustains important physical implications with overcoming some problems of previous rate equations. This rate model consists of ignition term which represents the formation of the hotspot due to void collapse and growth term which means the shock to detonation transition phenomena. Also, the theoretical model is used to investigate the combustion characteristics of certain energetic materials before running Hydrocode by pre-determination of unknown parameter, $b,\;G,\;x,\;I$. The analytical model provides efficient and highly accurate results rather than previous method which simulated the unconfined-rate-stick via the numerical means.

A study on development of reaction rate equation for reactive flow simulation in energetic materials (고에너지 물질의 연소반응 해석을 위한 반응속도식 개발 및 정의에 관한 연구)

  • Kim, Bo-Hoon;Yoh, Jai-Ick
    • Proceedings of the Korean Society of Propulsion Engineers Conference
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    • 2012.05a
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    • pp.331-341
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    • 2012
  • A modified Ignition and Growth(I&G) model which is necessary to simulate the combustion phenomena of energetic materials and an analytical model determining the unknown parameters of the reaction rate equation are proposed. The modified I&G model sustains important physical implications with overcoming some problems of previous rate equations. This rate model consist of Ignition term which represent the formation of the hotspot due to void collapse and Growth term which means the shock to detonation transition phenomena. Also, the theoretical model is used to investigate the combustion characteristics of certain energetic materials before running Hydrocode by pre-determination of unknown parameter, b, G, x, I. The analytical model provides efficient and highly accurate results rather than previous method which simulated the unconfined-rate-stick via the numerical means.

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