• Title/Summary/Keyword: SFT

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Dynamic Instability of Submerged Floating Tunnels due to Tendon Slack (긴장재 느슨해짐에 따른 해중 터널의 동적 불안정 거동)

  • Won, Deok Hee;Kim, Seungjun
    • Journal of Korean Society of Steel Construction
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    • v.29 no.6
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    • pp.401-410
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    • 2017
  • This study deals with dynamic instability of a tendon moored submerged floating tunnel (SFT) due to tendon slack. In general, environmental loadings such as wave and current govern SFT design. Especially, the wave force, whose amplitude and direction continuously change, directly induces the dynamic behavior of the SFT. The motion of the floating tube, induced by the wave force, leads dynamic response of the attached tendons and the dynamic change of internal forces of the tendons significantly affects to the fatigue design as well as the structural strength design. When the severe motion of the SFT occurs due to significant waves, tendons might lose their tension and slack so that the floating tube can be transiently instable. In this study, the characteristics of dynamic instability of the SFT due to tendon slack are investigated performing hydrodynamic analysis. In addition, the effects of draft, buoyancy-weight ratio, and tendon inclination on tendon slack and dynamic instability behavior are analytically investigated.

Risk Assessment of Submerged Floating Tunnels based on Fuzzy AHP (퍼지 AHP를 이용한 수중터널의 재해위험도 분석)

  • Han, Sang-Hun
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.13 no.7
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    • pp.3244-3251
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    • 2012
  • In the construction and operation of large marine structure, hazard risk analysis is one of important factors. Therefore, this paper investigates the hazard risk indexes and evaluates the risk level in the construction and operation of SFT on the basis of expert survey and Fuzzy analytic hierarchy process. Hazard risk is divided into natural hazard risk (earthquake, typhoon, tsunami, and ice collision) and human factor hazard risk (fire, explosion, traffic accident, ship or submarine collision). Also, the influence of hazard risk indexes on SFT was evaluated in tunnel tube, supporting system, ventilation tower, foundation, and connection part. As the hazard risk level of SFT is compared with those of bridge, underwater tunnel, and immersed tunnel, the intrinsic risk level of SFT was evaluated. Tsunami and earthquake had higher risk level in natural hazard risk, and the risk levels of fire and explosion were higher in human factor hazard risk. Hazard risk level of SFT was 1.4 times higher than immersed tunnel, and 3.2 times higher than bridge.

Prediction of Optimal Gluteal Intramuscular Needle Length by Skinfold Thickness Measurements in Korean Adults (피부주름두께 측정을 통한 성인의 둔부 근육주사 바늘의 최적 길이 예측)

  • Choi, Dong-Won;Sohng, Kyeong-Yae;Kim, Bum-Soo
    • Journal of Korean Academy of Nursing
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    • v.40 no.6
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    • pp.844-851
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    • 2010
  • Purpose: This study was conducted to assess optimal needle length for gluteal intramuscular injections (IM) via simple skinfold thickness (SFT). Methods: For this study, 190 healthy adults were recruited and grouped into eight groups according to gender and body mass index (BMI) (kg/$m^2$). The Korean Society for the Study of Obesity criteria defines a BMI under 20 as underweight, 20.1-22.9 as normal, 23-24.9 as overweight and over 25 as obese. For each participant, the SFT of dorsoguteal (DG) and ventrogluteal (VG) sites were measured using a caliper. Subcutaneous tissue thickness was acquired through ultrasonic images. Results: For men in the overweight and obese groups at the DG site, for the obese group at the VG site, and for women in the normal weight, overweight and obese groups at both sites, the mean subcutaneous tissue thickness exceeded 1.84 cm, the minimal length for a 1 inch needle used for IM. At the DG site, optimal intramuscular needle length (OINL) was 1.4 times in women and 1.0 times in men compared to SFT. At the VG site, OINL was 1.3 times in women and 0.9 times in men compared to SFT. Conclusion: The results of this study suggest that SFT is a reliable index to determine optimal needle length with minimal effort prior to IM.

Numerical study on the resonance behavior of submerged floating tunnels with elastic joint

  • Park, Joohyun;Kang, Seok-Jun;Hwang, Hyun-Joong;Cho, Gye-Chun
    • Geomechanics and Engineering
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    • v.29 no.3
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    • pp.207-218
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    • 2022
  • In submerged floating tunnels (SFTs), a next-generation maritime transportation infrastructure, the tunnel module floats in water due to buoyancy. For the effective and economical use of SFTs, connection with the ground is inevitable, but the stability of the shore connection is weak due to stress concentration caused by the displacement difference between the subsea bored tunnel and the SFT. The use of an elastic joint has been proposed as a solution to solve the stability problem, but it changes the dynamic characteristics of the SFT, such as natural frequency and mode shape. In this study, the finite element method (FEM) was used to simulate the elastic joints in shore connections, assuming that the ground is a hard rock without displacement. In addition, a small-scale model test was performed for FEM model validation. A parametric study was conducted on the resonance behavior such as the natural frequency change and velocity, stress, and reaction force distribution change of the SFT system by varying the joint stiffness under loading conditions of various frequencies and directions. The results indicated that the natural frequency of the SFT system increased as the stiffness of the elastic joint increased, and the risk of resonance was the highest in the low-frequency environment. Moreover, stress concentration was observed in both the SFT and the shore connection when resonance occurred in the vertical mode. The results of this study are expected to be utilized in the process of quantitative research such as designing elastic joints to prevent resonance in the future.

Two-stage Surgical Treatment of a Giant Solitary Fibrous Tumor Occupying the Thoracic Cavity

  • Song, Joon Young;Kim, Kyung Hwa;Kuh, Ja Hong;Kim, Tae Youn;Kim, Jong Hun
    • Journal of Chest Surgery
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    • v.51 no.6
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    • pp.415-418
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    • 2018
  • A solitary fibrous tumor (SFT) is a mesenchymal fibroblastic tumor inside the pleura, for which complete surgical resection is the standard treatment. For large SFTs, preoperative identification of tumor-feeding vessels using angiography is important for achieving complete resection without unexpected operative bleeding. Extensive adhesions can make resection difficult in a limited operative window, and pulmonary resection may be required to achieve complete SFT resection. Herein, we report successful resection of a large pleural SFT in a 39-year-old man without any complications using a 2-stage approach, in which ligation of the feeding vessels through small another operative window was the first step.

Genetic Parameters for Traits in Performance and Progeny Tests and Their Genetic Relationships in Japanese Black Cattle

  • Oikawa, T.;Hoque, M.A.;Hitomi, T.;Suzuki, K.;Uchida, H.
    • Asian-Australasian Journal of Animal Sciences
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    • v.19 no.5
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    • pp.611-616
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    • 2006
  • Genetic parameters for performance traits on 409 bulls and growth and carcass traits on 591 of their steer progeny were estimated in Japanese Black cattle with Gibbs sampling. Traits of bulls included body weight at the start (BWS) and finish (BWF) of test, daily gain (DG), concentrate, roughage and TDN intake, and TDN conversion ratio. Progeny traits were BWS, BWF, DG, rib eye area, marbling score (MSR), dressing percentage and subcutaneous fat thickness (SFT). In bulls, heritabilities were high for BWS (0.50) and BWF (0.63) and moderate for concentrate (0.48) and TDN intake (0.45), while in progeny, the heritability for all the studied traits was moderate to high (ranging from 0.30 to 0.73), highlighting the potential for genetic improvement of these traits. Genetic correlations between TDN intake and growth traits (BWS, BWF and DG) in bulls were highly positive (ranging from 0.77 to 0.94). The weak but negative genetic correlation (-0.20) between MSR and SFT in progeny indicated that improvement of beef marbling without increasing subcutaneous fat deposition could be possible. The estimated genetic correlations of roughage intake of bulls with body weights (BWS and BWF) and MSR of their progeny were moderate (ranging from 0.35 to 0.52). On the basis of the selection for bulls, growth traits and TDN intake correlated positively with SFT (ranging from 0.43 to 0.53) of their progeny, suggesting the necessity of controlling the increase of SFT in selection programs.

The Roles of the SNARE Protein Sed5 in Autophagy in Saccharomyces cerevisiae

  • Zou, Shenshen;Sun, Dan;Liang, Yongheng
    • Molecules and Cells
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    • v.40 no.9
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    • pp.643-654
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    • 2017
  • Autophagy is a degradation pathway in eukaryotic cells in which aging proteins and organelles are sequestered into double-membrane vesicles, termed autophagosomes, which fuse with vacuoles to hydrolyze cargo. The key step in autophagy is the formation of autophagosomes, which requires different kinds of vesicles, including COPII vesicles and Atg9-containing vesicles, to transport lipid double-membranes to the phagophore assembly site (PAS). In yeast, the cis-Golgi localized t-SNARE protein Sed5 plays a role in endoplasmic reticulum (ER)-Golgi and intra-Golgi vesicular transport. We report that during autophagy, sed5-1 mutant cells could not properly transport Atg8 to the PAS, resulting in multiple Atg8 dots being dispersed into the cytoplasm. Some dots were trapped in the Golgi apparatus. Sed5 regulates the anterograde trafficking of Atg9-containing vesicles to the PAS by participating in the localization of Atg23 and Atg27 to the Golgi apparatus. Furthermore, we found that overexpression of SFT1 or SFT2 (suppressor of sed5 ts) rescued the autophagy defects in sed5-1 mutant cells. Our data suggest that Sed5 plays a novel role in autophagy, by regulating the formation of Atg9-containing vesicles in the Golgi apparatus, and the genetic interaction between Sft1/2 and Sed5 is essential for autophagy.

Adiposity Measurements and Related Characteristics of Young Children Born Prematurely (미숙아로 출생한 학령전기 아동의 비만도 측정과 관련 특성)

  • Ahn, Youngmee;Sohn, Min;Lee, Sangmi
    • Child Health Nursing Research
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    • v.24 no.2
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    • pp.220-228
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    • 2018
  • Purpose: This study was conducted to measure adiposity and to investigate related factors in preschoolers born prematurely. Methods: A longitudinal follow-up study was conducted with 52 preschoolers at 5 years of corrected age among 343 preterm infants. Their adiposity status was evaluated based on measurements of body mass index, subscapular and triceps skin fold thickness (SFT), waist circumference, waist-to-height ratio, and mid-arm circumference at a home visit. Results: The findings showed that SFT measurements, particularly at the triceps, reflected the degree of adiposity more accurately than other conventional measures. A shorter gestation, older maternal age, and the mother having more years of formal education were associated with higher levels of adiposity in the preschoolers. Conclusion: The adiposity of children born prematurely needs to be thoroughly monitored with additional SFT measurements, considering the risk of accelerated growth patterns overriding regular catch-up growth in children born prematurely.

Dynamic and structural responses of a submerged floating tunnel under extreme wave conditions

  • Jin, Chungkuk;Kim, MooHyun
    • Ocean Systems Engineering
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    • v.7 no.4
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    • pp.413-433
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    • 2017
  • The dynamic and structural responses of a 1000-m long circular submerged floating tunnel (SFT) with both ends fixed under survival irregular-wave excitations are investigated. The floater-mooring nonlinear and elastic coupled dynamics are modeled by a time-domain numerical simulation program, OrcaFlex. Two configurations of mooring lines i.e., vertical mooring (VM) and inclined mooring (IM), and four different buoyancy-weight ratios (BWRs) are selected to compare their global performances. The result of modal analysis is included to investigate the role of the respective natural frequencies and elastic modes. The effects of various submergence depths are also checked. The envelopes of the maximum/minimum horizontal and vertical responses, accelerations, mooring tensions, and shear forces/bending moments of the entire SFT along the longitudinal direction are obtained. In addition, at the mid-section, the time series and the corresponding spectra of those parameters are also presented and analyzed. The pros and cons of the two mooring shapes and high or low BWR values are systematically analyzed and discussed. It is demonstrated that the time-domain numerical simulation of the real system including nonlinear hydro-elastic dynamics coupled with nonlinear mooring dynamics is a good method to determine various design parameters.

Preliminary study on the ground behavior at shore connection of submerged floating tunnel using numerical analysis

  • Kang, Seok-Jun;Kim, Jung-Tae;Cho, Gye-Chun
    • Geomechanics and Engineering
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    • v.21 no.2
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    • pp.133-142
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    • 2020
  • Submerged floating tunnel (SFT) is a type of tunnel which causes the tunnel segments to float in the water. When the SFTs are connected to the ground, the connection between the SFT and the subsea bored tunnel is fragile due to the difference in behavioral characteristics between the two types of tunnels. Therefore, special design and construction methods are needed to ensure the stability of the area around the connection. However, since previous research on the stability of the connection site has not been undertaken enough, the basic step necessitates the evaluation of ground behavior at the shore connection. In this study, the numerical analysis targeting the shore connection between the subsea bored tunnel and the SFT was simulated. The strain concentration at the shore connection was analyzed by numerical simulation and the effects of several factors were examined. The results showed the instability in the ground close to the shore connection due to the imbalance in the behavior of the two types of tunnels; the location of the strain concentration varies with different environmental and structural conditions. It is expected that the results from this study can be utilized in future studies to determine weak points in the shore connection between the submerged floating tunnel and the subsea bored tunnel, and devise methods to mitigate the risks.