• Title/Summary/Keyword: pressure time

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A Study on Lateral Displacement of Caisson Constructed on Improved Ground (개량 지반에 설치된 케이슨의 측방변위에 대한 연구)

  • Kim, Myunghak;Lee, Sangwook;Yoon, Minseung;Han, Byungwon
    • Journal of the Korean GEO-environmental Society
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    • v.12 no.4
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    • pp.33-41
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    • 2011
  • In case of building up port facilities on soft ground, unsymmetrical surcharge of embankment, which make the excess pore water pressure to increase, causes to occur lateral displacement due to plasticity of soil. A study on lateral displacement and settlement of the caisson, which is installed on improved ground, was accomplished. The field measurement data and calculated values obtained from FEM program of Plaxis were compared and analyzed. For numerical analysis, the properties of soils, constructions stage and time were considered. Lateral displacement was measured at the point of inclinometers installed in front of caisson. Settlement was measured at the center of extra embankment behind of caisson. Comparison of measured and calculated for lateral displacement showed that the calculated value was greater than the measured, and increasing trend was different. The calculated value showed step increasing as step extra embankment applied, whereas the measured gradually was increased. For settlement of embankment, the amount of both measured and calculated were similar, but the trend was different like that of lateral movement.

An Analysis of the Effect of PBD Discharge Capacity to Leave Period (방치기간에 따른 PBD의 통수능 효과 분석)

  • Lee, Keeyong;Park, Minchul;Jeong, Sangguk;Lee, Song
    • Journal of the Korean GEO-environmental Society
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    • v.12 no.10
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    • pp.39-49
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    • 2011
  • Recently PBD method, one of acceleration of consolidation methods is used in the soft ground to shorten consolidation time for fast settlement during construction. It is economical and easy to work. Discharge capacity of PBD is sensitive in proportion to thickness of soft ground layer, and drainage of PBD declines due to disturbance effect in surrounding ground by mandrel used for vertical drainage setting and setting machines and type. Also, deviation of discharge capacity is large according to ground condition, construction condition and soil properties. In addition, when embankment loading is not conducted instantly after PBD setting due to rain or lack of embankment material supply, it causes leaving period problems. But cause and analysis of those problems for discharge capacity is lack. So, in this test, ground improvement and discharge capacity is investigated by implementing composite discharge capacity test for analysis of an effect factor of PBD discharge capacity with leaving period. After fixing the vertical drain on a cylindrical cylinder, put churned sample into the cylinder. Then leave 0day, 30day, 60day and 90day. And then, load following the loading step of 30, 70 and 120kPa using a pressure device. As a result, the longer leaving period, discharge capacity is reduced. It is caused by a decrease of discharge area caused by creep transformation moisture absorption of PBD filter after long leaving period.

Effects of Kettlebell Training on Functional Movement Screen and Balance in Middle School Baseball Players (케틀벨 훈련이 중학교 야구선수의 기능적 움직임(Functional Movememt Screen)과 균형성에 미치는 영향)

  • Kim, Tae-Yoon;Park, Woo-Young;Byun, Yong-Hyun
    • Journal of the Korean Applied Science and Technology
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    • v.39 no.1
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    • pp.96-107
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    • 2022
  • The purpose of this study was to demonstrate the effects of 8weeks Kettlebell training on the FMS and Balance in Middle school baseball player. Fourteen middle school baseball players were randomly assigned to a kettlebell group (n=8) and a control group (n=6), and kettlebell training was applied twice a week for 60 minutes. And the FMS, Y-balance test and static and dynamic balance test using smart shoes were tested before and after kettlebell training. Repeated two-way ANOVA measures was performed both before and after the exercise to verify the effect of kettlebell training. Also, if there was an interaction between time and group, a paired sample t-test was performed for each group. As a results of the study, FMS score showed a significant difference in IL (Inline Lunge) and TS(Total Score), and there was no significant difference in other variables of FMS. The YBT score showed a significant difference in all YBT variables except for the left AT. And the balance test using smart shoes, there was no significant interaction effect between group and period in all variables. In conclusion, it was found that the application of kettlebell training in middle school baseball players had an effects on the FMS and YBT scores related to functional movement and functional balance, but it did not affect the static/dynamic balance test using smart shoes evaluated by the foot pressure method. It seems that the results of this study can be provided as basic data necessary for planning a training program for middle school baseball players.

Comparison of Liquefaction Assessment Results with regard to Geotechnical Information DB Construction Method for Geostatistical Analyses (지반 보간을 위한 지반정보DB 구축 방법에 따른 액상화 평가 결과 비교)

  • Kang, Byeong-Ju;Hwang, Bum-Sik;Bang, Tea-Wan;Cho, Wan-Jei
    • Journal of the Korean Geotechnical Society
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    • v.38 no.4
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    • pp.59-70
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    • 2022
  • There is a growing interest in evaluating earthquake damage and determining disaster prevention measures due to the magnitude 5.8 earthquake in Pohang, Korea. Since the liquefaction phenomena occurred extensively in the residential area as a result of the earthquake, there was a demand for research on liquefaction phenomenon evaluation and liquefaction disaster prediction. Liquefaction is defined as a phenomenon where the strength of the ground is completely lost due to a sudden increase in excess pore water pressure caused due to large dynamic stress, such as an earthquake, acting on loose sand particles in a short period of time. The liquefaction potential index, which can identify the occurrence of liquefaction and predict the risk of liquefaction in a targeted area, can be used to create a liquefaction hazard map. However, since liquefaction assessment using existing field testing is predicated on a single borehole liquefaction assessment, there has been a representative issue for the whole targeted area. Spatial interpolation and geographic information systems can help to solve this issue to some extent. Therefore, in order to solve the representative problem of geotechnical information, this research uses the kriging method, one of the geostatistical spatial interpolation techniques, and constructs a geotechnical information database for liquefaction and spatial interpolation. Additionally, the liquefaction hazard map was created for each return period using the constructed geotechnical information database. Cross validation was used to confirm the accuracy of this liquefaction hazard map.

Evaluation Study of Blast Resistance and Structural Factors in the Explosive Simple Storage by Numerical Analysis (수치해석을 통한 화약류 간이저장소의 방폭성 및 구조인자 평가연구)

  • Jung, Seung-Won;Kim, Jung-Gyu;Kim, Jun-Ha;Kim, Nam-Soo;Kim, Jong-Gwan
    • Tunnel and Underground Space
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    • v.32 no.2
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    • pp.160-172
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    • 2022
  • The design regulations for simple explosive storage in Korea only stipulate standards for the materials and thickness of the wall of the structure because the amount of explosives that can be stored is small. There is concern about secondary damage during an internal explosion in a simple storage facility, and it is necessary to reexamine the current standards. The numerical analysis for the TNT 15 kg explosion inside the simple storage was carried out by setting the factors using the robust experimental design method. The displacement of the structure generated under the same time condition was analyzed, and the contribution was evaluated. The contribution of concrete thickness was the highest, and the contribution of concrete strength and rebar arrangement was lower than that of concrete thickness. The reinforcement diameter contributed extremely little to the displacement. The structural standards of the simple storage that are currently applied are insufficient on blast resistance, and it is necessary to present new design standards. Therefore, the design factor to be applied later analysis and actual experiments were taken into consideration. For the design variables, the thickness of the concrete was 15 cm considering the displacement, the concrete strength was selected as general concrete considering the inlet discharge pressure, the factor with the lowest average displacement was selected for the reinforcement arrangement and the diameter of the reinforcement, the factor with the smallest level was selected in consideration of economic feasibility because the difference in displacement was low.

Development of CanSat System for Collecting Weather Information With Autorotating Science Payload Ejection Function (자동회전 과학 탑재체 사출 기능을 갖춘 기상정보 수집용 캔위성 체계 개발)

  • Kim, Youngjun;Park, Junsoo;Nam, Jaeyoung;Lee, Junhyuck;Choi, Yunwon;Yoo, Seunghoon;Lee, Sanghyun;Lee, Younggun
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.50 no.8
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    • pp.573-581
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    • 2022
  • This paper deals with the development of CanSat system, which ejects two maple seed-type autorotating science payloads and collects weather information. The CanSat consists of two autorotating science payloads and a container. The container is equipped with devices for launching science payloads and communication with the ground station, and launches science payloads one by one at different designated altitudes. The science payload consists of a space for loading and a large wing, and rotates to generate lift for slowing down the fall speed. Specifically, after being ejected, it descends at a speed of 20 m/s or less, measures the rotation rate, atmospheric pressure, and temperature, and transmits the measured value to the container at a rate of once per second. The communication system is a master-slave structure, and the science payload transmits all data to the master container, which aggregates both the received data and its own data, and transmits it to the ground station. All telemetry can be checked in real time using the ground station software developed in-house. A simulation was performed in the simulation environment, and the performance of the CanSat system that satisfies the mission requirements was confirmed.

A Study of Dyeing Properties of Cotton Fabrics Under Supercritical CO2 Depending on Dyestuff : by C.I. Disperse orange 155, C.I. Disperse red 167 (초임계 유체 염색용 염료에 따른 면 섬유의 염색 특성 : C.I. Disperse orange 155, C.I. Disperse red 167)

  • Choi, Hyunseuk;Kim, Hunmin;Jeon, Taeyoung
    • Textile Coloration and Finishing
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    • v.34 no.2
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    • pp.93-101
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    • 2022
  • In this study, the dyeing properties of supercritical fluid dyed cotton fabrics were investigated which use two types of dyes, such as C.I. Disperse orange and C.I. Disperse red 167. Dyeing temperature, pressure and leveling time were equally applied at 130 ℃, 250 bar, and 60 minutes with reference to the related literature, and experiments were performed at concentrations of 0.04, 0.1, 0.4 and 0.8 % o.w.f with different concentrations. Dyeability was confirmed through measurement of washing fastness and color coordinate, and a calibration curve of each dye was drawn up and the absorbance of the residual dye was measured to confirm the amount of residual dye and the dye exhaustion rate at the corresponding concentration. As a result of color difference measurement, as the concentration increased, the L* value decreased and the K/S value increased. However, as the concentration increased, the increase in K/S value decreased compared to the input amount, and this tendency was more obvious in C.I. Disperse red 167 than in C.I. Disperse orange 155. The dye exhaustion rate which was calculated by using the amount of residual dye in the pot was also C.I. Disperse orange 155 was 96.16 % and C.I. Disperse red 167 was 94.57 %. However, as the dyeing concentration increased, the dye exhaustion rate decreased, that C.I. Disperse orange was 95.33 % and C.I. Disperse red 167 was 90.63 %. As a result of the washing fastness test for both dyes, dyed samples of which concentrations were 0.4 and 0.8 % o.w.f decreased by 0.5 ~ 1.0 grade. This is predicted because the dye did not completely adhere to the amorphous region of the cotton fiber and the dye simply adsorbed. The fastness to rubbing also maintained at least grade 3-4 up to the 0.1 % o.w.f concentration, but at the concentration of 0.4 % o.w.f or higher, it fell to grade 1 or lower, showing a very poor friction fastness.

Preparation of High Energy Density Lithium Anode for Thermal Batteries and Electrochemical Properties Thereof (열전지용 고에너지 밀도 리튬 음극 제조 및 이의 전기화학적 특성)

  • Im, Chae-Nam;Yu, Hye-Ryeon;Yoon, HyunKi;Cho, Jang-Hyeon
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.35 no.4
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    • pp.398-406
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    • 2022
  • In order to increase the electrochemical performance of thermal battery anode, LIFT anode having the same weight but a larger lithium content in electrodes was fabricated by mixing lithium, iron and titanium. By applying these electrodes, a single cell and a thermal battery were prepared, and the effect of LIFT anode on electrochemical performance was evaluated. The LIFT-applied single cell presented a better cell performance than LIFe-applied single cell at 500℃ and 550℃. The discharge performance of LIFT-applied single cell, which included the operating time (787s), specific capacity (1,683 Asg-1), and electrode utilization (80.7%), was improved collectively compared to the LIFe applied single cell (736s, 1,245 As g-1, and 74.6%) at 500℃. As the discharge progressed, the internal resistance of LIFT anode decreased, because the lithium migration path was formed due to the presence of large titanium particles among iron particles. These results were analyzed in terms of the microstructure of electrode using SEM. Energy density of LIFT-applied single cell also increased by 10% to 142.1 Wh kg-1 compared to that of LIFe-applied single cell (127.4 Wh kg-1). In addition, the LIFT-applied single cell presented a stable discharge performance for 6,500s without a short circuit which could occur by molten lithium under an open circuit voltage condition with a high pressure (4 kgf cm-2). As observed in the high temperature thermal battery performance tests, the voltage and specific capacity of LIFT-applied thermal battery are superior to those of LIFe-applied thermal batteries, indicating that the energy density of LIFT-applied thermal batteries should remarkably increase.

Clinical Experiences of High-Risk Pulmonary Thromboembolism Receiving Extracorporeal Membrane Oxygenation in Single Institution

  • Jang, Joonyong;Koo, So-My;Kim, Ki-Up;Kim, Yang-Ki;Uh, Soo-Taek;Jang, Gae-Eil;Chang, Wonho;Lee, Bo Young
    • Tuberculosis and Respiratory Diseases
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    • v.85 no.3
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    • pp.249-255
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    • 2022
  • Background: The main cause of death in pulmonary embolism (PE) is right-heart failure due to acute pressure overload. In this sense, extracorporeal membrane oxygenation (ECMO) might be useful in maintaining hemodynamic stability and improving organ perfusion. Some previous studies have reported ECMO as a bridge to reperfusion therapy of PE. However, little is known about the patients that benefit from ECMO. Methods: Patients who underwent ECMO due to pulmonary thromboembolism at a single university-affiliated hospital between January 2010 and December 2018 were retrospectively reviewed. Results: During the study period, nine patients received ECMO in high-risk PE. The median age of the patients was 60 years (range, 22-76 years), and six (66.7%) were male. All nine patients had cardiac arrests, of which three occurred outside the hospital. All the patients received mechanical support with veno-arterial ECMO, and the median ECMO duration was 1.1 days (range, 0.2-14.0 days). ECMO with anticoagulation alone was performed in six (66.7%), and ECMO with reperfusion therapy was done in three (33.3%). The 30-day mortality rate was 77.8%. The median time taken from the first cardiac arrest to initiation of ECMO was 31 minutes (range, 30-32 minutes) in survivors (n=2) and 65 minutes (range, 33-482 minutes) in non-survivors (n=7). Conclusion: High-risk PE with cardiac arrest has a high mortality rate despite aggressive management with ECMO and reperfusion therapy. Early decision to start ECMO and its rapid initiation might help save those with cardiac arrest in high-risk PE.

A Study on the Characteristics in Chinese Contemporary Tragic Films - Focused on the film - (영화 <5일의 마중>으로 본 현대 중국 비극 영화의 특성 연구)

  • Wu, Ying Zhe
    • Journal of Korea Entertainment Industry Association
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    • v.15 no.3
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    • pp.65-73
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    • 2021
  • This research analyzes the characteristics of Chinese tragic films with Chinese traditional ethical ideology as the core, analyzes its specific performance in the plot and ending setting of the film , and analyzes the director's tragic narrative strategy of cultural reconciliation in the face of political environment to understand the characteristics of Chinese contemporary tragic films.The film is a Chinese contemporary tragic film with The Great Cultural Revolution as its historical background. This film is a representative film of Chinese contemporary tragic films. The classic plot has played a certain role in the expression of Chinese traditional ethical ideology such as fatalism and optimistic attitude to life. The male lead's thought changes interpret the Chinese-style tragedy characteristics containing Chinese traditional ethical ideology. In the setting of the ending, the film broke through the "happy ending" model of Chinese traditional tragedies, and chose the open ending of "one tragedy to the end", further showing the time feature of Chinese contemporary tragic film. The euphemism and tenderness of the film as a tragic film is not only due to the compromise with the political culture of power, but also the result of the director's in-depth understanding of the aesthetics of Chinese tragedy. Through the use of symbolic signs in the film language, it has formed the implicit characteristics of the film narrative in the tragic aesthetic experience. In this paper, the author conducts text analysis for the film and discusses presentation of Director Yimou Zhang's tragic feelings and using the tragic narrative strategy of cultural reconciliation to show his creative wisdom in pursuing artistic breakthroughs under political pressure.