• Title/Summary/Keyword: Dynamic Pressure

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The Effects of Coordinative Locomotor Training Program for Life-Care Promotion on Balance of Obese Elderly Women (라이프케어 증진을 위한 협응적 이동훈련 프로그램이 비만 여성노인의 균형에 미치는 영향)

  • Lee, Dong-Ryul
    • Journal of Korea Entertainment Industry Association
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    • v.14 no.1
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    • pp.17-25
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    • 2020
  • The purpose of this study was to examine the effects of coordinative locomotor training (CLT) program on the balance for the promotion of life care of elderly obese women. Ten participants of elderly obese women who were able to walk independently without surgery experience of lumbar, hip or knee joint within the past year were recruited and under went the pretest, CLT (20 sessions), followed by the post-test. The test included BMI test using In-body, joint kinematics using myoVIDEO, muscle activation using surface EMG test (erector spinae (ER), external oblique abdominalis (EO), quadriceps femoris (Quad), hamstring muscle (Ham)) and balance tests including dynamic balance test using forced treadmill, Berg balance scale (BBS) and timed up go (TUG). The CLT program was conducted 60 minutes a day, 5 days a week, over 4 weeks period. As a result of this study, The the trunk and hip joints kinematics during the stance and swing phases of gait were a statistical significance levels were set at p <0.05. The ER and EO muscle activation were significantly improved after intervention (p <0.05). The length of gait line and single support line of change of center of pressure (COP) were significantly increased after intervention (p <0.05). The BBS and TUG were also significantly enhanced after intervention (p <0.05). The results of this study showed that CLT program for the improvement of life care had significant effects on improving postural instability, muscle weakness, reduced balance ability and falling risk of obese elderly women. Therefore, it is recommended to apply CLT program to improve life-care through improving balance ability and preventing fall of obese elderly women.

Analysis of the Characteristics of Liquidization Behavior of Sand Ground in Korea Using Repeated Triaxial Compression Test (반복삼축압축시험을 이용한 국내 모래지반의 액상화 거동 특성 비교)

  • Seo, Hyeok;Kim, Daehyeon
    • The Journal of Engineering Geology
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    • v.31 no.4
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    • pp.493-506
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    • 2021
  • Liquefaction refers to a phenomenon in which excessive pore water pressure occurs when a dynamic load such as an earthquake rapidly acts on a loose sandy soil saturated with soil, and the ground loses effective stress and becomes liquefied. The indoor repeated test for liquefaction evaluation can be confirmed through the repeated triaxial compression test and the repeated shear test. In this regard, this study tried to confirm the liquefaction resistance strength according to the relative density and particle size distribution of sand using the repeated triaxial compression test. As a result of the experiment, it was confirmed that the liquefaction resistance strength increased as the relative density increased regardless of the soil classification, and the liquefaction resistance strength according to the particle size distribution of the sand was confirmed that the liquefaction resistance strength of the SP sample close to SW was significantly higher. In addition, as a result of analyzing 30% of fine powder compared to 0% of fine powder, as the relative density increased to 40~70%, the liquefaction resistance strength decreased by 5~20%, and the domestic weathered soil ground had a fine liquefaction resistance strength compared to Jumunjin standard sand. When the minute was 10%, it was measured to be 30% or more, and when the fine particle was 30%, it was measured to be less than 50%.

Evaluation of Water Quality Change by Membrane Damage to Pretreatment Process on SDI in Wastewater Reuse (하수재이용에서 전처리 막 손상에 의한 수질변화가 SDI에 미치는 영향평가)

  • Lee, Min Soo;Seo, Dongjoo;Lee, Yong-Soo;Chung, Kun Yong
    • Membrane Journal
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    • v.32 no.4
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    • pp.253-263
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    • 2022
  • This study suggests a guideline for designing unit process of wastewater reuse in terms of a maintenance of the process based on critical parameters to draw a high quality performance of RO unit. Defining the parameters was done by applying membrane integrity test (MIT) in pretreatment process utilizing lab-scale MF. SDI is utilized for judging whether permeate is suitable to RO unit. However, result said TOC concentration matching with particle count analysis is better for judging the permeate condition. When membrane test pressure (Ptest) was measured to derive log removal value in PDT, virgin state of membrane fiber was used to measure dynamic contact angle utilizing surface tension of the membrane fiber. Actually, foulant affects to the state of membrane surface, and it decreases the Ptest value along with time elapsed. Consequently, LRVDIT is also affected by Ptest value. Thus, sensitivity of direct integrity test descends with result of Ptest value change, so Ptest value should be considered not the virgin state of the membrane but its current state. Overall, this study focuses on defining design parameters suitable to MF pretreatment for RO process in wastewater reuse by assessing its impact. Therefore, utilities can acknowledge that the membrane surface condition must be considered when users conduct the direct integrity test so that Ptest and other relative parameter used to calculate LRVDIT are adequately measured.

Dynamic Behavior of Caisson Type Breakwater Considering Typhoon-induced Wave Loading Before and After Earthquakes (태풍 파랑과 지진을 연계한 케이슨식 방파제의 동적거동)

  • Hyeonsu Yun;Byeongjin Roh;Seong-Kyu Yun;Gichun Kang
    • Journal of the Korean Geosynthetics Society
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    • v.23 no.1
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    • pp.49-60
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    • 2024
  • Recently, the frequency and intensity of typhoon-induced wave loading are increasing due to changed marine environments such as climate change. In addition, frequent earthquakes are causing a lot of damage around the world, including in Japan, Chile, Haiti, China, and Indonesia. In Korea, damage from typhoons has also been increasing since the 2000s, and the frequency and intensity of earthquakes are also increasing. Korea is surrounded by sea on three sides, so typhoons can cause a lot of damage to coastal structures, and earthquakes also cause a lot of damage to coastal structures. As such, the frequency and intensity of typhoon-induced wave loading and earthquakes are increasing both domestically and internationally, but there is no research linking typhoons and earthquakes. Therefore, in this study, numerical analysis was performed for a total of four cases by linking typhoon waves and earthquakes to the caisson breakwater. Numerical analysis was performed by applying wave loads in Case 1 and seismic wave in Case 2, seismic wave after wave loads in Case 3, and wave loads after seismic wave in Case 4. As a result of the numerical analysis, it was confirmed that in Case 3 and Case 4, which linked a typhoon and earthquakes, the damage caused by each load increased compared to Case 1 and Case 2 because the load was applied while the existing ground strength was reduced. In addition, it was confirmed that the greatest damage occurred in Case 3, in which seismic wave were applied after the wave loads.

A New Detailed Assessment for Liquefaction Potential Based on the Liquefaction Driving Effect of the Real Earthquake Motion (실지진하중의 액상화 발생특성에 기초한 액상화 상세평가법)

  • 최재순;강한수;김수일
    • Journal of the Korean Geotechnical Society
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    • v.20 no.5
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    • pp.145-159
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    • 2004
  • The conventional method for assessment of liquefaction potential proposed by Seed and Idriss has been widely used in most countries because of simplicity of tests. Even though various data such as stress, strain, stress path, and excess pore water pressure can be obtained from the dynamic test, especially, two simple experimental data such as the maximum deviatoric stress and the number of cycles at liquefaction have been used in the conventional assessment. In this study, a new detailed assessment for liquefaction potential to reflect both characteristics of real earthquake motion and dynamic soil resistance is proposed and verified. In the assessment, the safety factor of the liquefaction potential at a given depth of a site can be obtained by the ratio of a resistible cumulative plastic shear strain determined through the performance of the conventional cyclic test and a driving cumulative plastic shear strain calculated from the shear strain time history through the ground response analysis. The last point to cumulate the driving plastic shear strain to initiate soil liquefaction is important for this assessment. From the result of cyclic triaxial test using real earthquake motions, it was concluded that liquefaction under the impact-type earthquake loads would initiate as soon as a peak loading signal was reached. The driving cumulative plastic shear strain, therefore, can be determined by adding all plastic shear strains obtained from the ground response analysis up to the peak point. Through the verification of the proposed assessment, it can be concluded that the proposed assessment for liquefaction potential can be a progressive method to reflect both characteristics of the unique soil resistance and earthquake parameters such as peak earthquake signal, significant duration time, earthquake loading type, and magnitude.

Dynamic response of segment lining due to train-induced vibration (세그먼트 라이닝의 열차 진동하중에 대한 동적 응답특성)

  • Gyeong-Ju Yi;Ki-Il Song
    • Journal of Korean Tunnelling and Underground Space Association
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    • v.25 no.4
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    • pp.305-330
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    • 2023
  • Unlike NATM tunnels, Shield TBM tunnels have split linings. Therefore, the stress distribution of the lining is different even if the lining is under the same load. Representative methods for analyzing the stress generated in lining in Shield TBM tunnels include Non-joint Mode that does not consider connections and a 2-ring beam-spring model that considers ring-to-ring joints and segment connections. This study is an analysis method by Break-joint Mode. However, we do not consider the structural role of segment lining connections. The effectiveness of the modeling is verified by analyzing behavioral characteristics against vibration loads by modeling with segment connection interfaces to which vertical stiffness and shear stiffness, which are friction components, are applied. Unlike the Non-joint mode, where the greatest stress occurs on the crown for static loads such as earth pressure, the stress distribution caused by contact between segment lining and friction stiffness produced the smallest stress in the crown key segment where segment connections were concentrated. The stress distribution was clearly distinguished based on segment connections. The results of static analysis by earth pressure, etc., produced up to seven times the stress generated in Non-joint mode compared to the stress generated by Break-joint Mode. This result is consistent with the stress distribution pattern of the 2-ring beam-spring model. However, as for the stress value for the train vibration load, the stress of Break-joint Mode was greater than that of Non-joint mode. This is a different result from the static mechanics concept that a segment ring consisting of a combination of short members is integrated in the circumferential direction, resulting in a smaller stress than Non-joint mode with a relatively longer member length.

The hydrodynamic characteristics of the canvas kite - 2. The characteristics of the triangular canvas kite - (캔버스 카이트의 유체역학적 특성에 관한 연구 - 2. 삼각형 캔버스 카이트의 특성 -)

  • Bae, Bong-Seong;Bae, Jae-Hyun;An, Heui-Chun;Lee, Ju-Hee;Shin, Jung-Wook
    • Journal of the Korean Society of Fisheries and Ocean Technology
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    • v.40 no.3
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    • pp.206-213
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    • 2004
  • As far as an opening device of fishing gears is concerned, applications of a kite are under development around the world. The typical examples are found in the opening device of the stow net on anchor and the buoyancy material of the trawl. While the stow net on anchor has proved its capability for the past 20 years, the trawl has not been wildly used since it has been first introduced for the commercial use only without sufficient studies and thus has revealed many drawbacks. Therefore, the fundamental hydrodynamics of the kite itself need to ne studied further. Models of plate and canvas kite were deployed in the circulating water tank for the mechanical test. For this situation lift and drag tests were performed considering a change in the shape of objects, which resulted in a different aspect ratio of rectangle and trapezoid. The results obtained from the above approaches are summarized as follows, where aspect ratio, attack angle, lift coefficient and maximum lift coefficient are denoted as A, B, $C_L$ and $C_{Lmax}$ respectively : 1. Given the triangular plate, $C_{Lmax}$ was produced as 1.26${\sim}$1.32 with A${\leq}$1 and 38$^{\circ}$B${\leq}$42$^{\circ}$. And when A${\geq}$1.5 and 20$^{\circ}$${\leq}$B${\leq}$50$^{\circ}$, $C_L$ was around 0.85. Given the inverted triangular plate, $C_{Lmax}$ was 1.46${\sim}$1.56 with A${\leq}$1 and 36$^{\circ}$B${\leq}$38$^{\circ}$. And When A${\geq}$1.5 and 22$^{\circ}$B${\leq}$26$^{\circ}$, $C_{Lmax}$ was 1.05${\sim}$1.21. Given the triangular kite, $C_{Lmax}$ was produced as 1.67${\sim}$1.77 with A${\leq}$1 and 46$^{\circ}$B${\leq}$48$^{\circ}$. And when A${\geq}$1.5 and 20$^{\circ}$B${\leq}$50$^{\circ}$, $C_L$ was around 1.10. Given the inverted triangular kite, $C_{Lmax}$ was 1.44${\sim}$1.68 with A${\leq}$1 and 28$^{\circ}$B${\leq}$32$^{\circ}$. And when A${\geq}$1.5 and 18$^{\circ}$B${\leq}$24$^{\circ}$, $C_{Lmax}$ was 1.03${\sim}$1.18. 2. For a model with A=1/2, an increase in B caused an increase in $C_L$ until $C_L$ has reached the maximum. Then there was a tendency of a very gradual decrease or no change in the value of $C_L$. For a model with A=2/3, the tendency of $C_L$ was similar to the case of a model with A=1/2. For a model with A=1, an increase in B caused an increase in $C_L$ until $C_L$ has reached the maximum. And the tendency of $C_L$ didn't change dramatically. For a model with A=1.5, the tendency of $C_L$ as a function of B was changed very small as 0.75${\sim}$1.22 with 20$^{\circ}$B${\leq}$50$^{\circ}$. For a model with A=2, the tendency of $C_L$ as a function of B was almost the same in the triangular model. There was no considerable change in the models with 20$^{\circ}$B${\leq}$50$^{\circ}$. 3. The inverted model's $C_L$ as a function of increase of B reached the maximum rapidly, then decreased gradually compared to the non-inverted models. Others were decreased dramatically. 4. The action point of dynamic pressure in accordance with the attack angle was close to the rear area of the model with small attack angle, and with large attack angle, the action point was close to the front part of the model. 5. There was camber vertex in the position in which the fluid pressure was generated, and the triangular canvas had large value of camber vertex when the aspect ratio was high, while the inverted triangular canvas was versa. 6. All canvas kite had larger camber ratio when the aspect ratio was high, and the triangular canvas had larger one when the attack angle was high, while the inverted triangluar canvas was versa.

Dosimetric Characterization of an Ion Chamber Matrix for Intensity Modulated Radiation Therapy Quality Assurance (세기변조방사선치료 선량분포 확인을 위한 2차원적 이온전리함 배열의 특성분석)

  • Lee, Jeong-Woo;Hong, Se-Mie;Kim, Yon-Lae;Choi, Kyoung-Sik;Jung, Jin-Beom;Lee, Doo-Hyun;Suh, Tae-Suk
    • Progress in Medical Physics
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    • v.17 no.3
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    • pp.131-135
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    • 2006
  • A commercial ion chamber matrix was examined the characteristics and its performance for radiotherapy qualify assurance. The device was the I'mRT 2D-MatriXX (Scanditronix-Wellhofer, Schwarzenbruck, Germany). The 2D-MatriXX device consists of a 1020 vented ion chamber array, arranged in $24{\times}24cm^2$ matrix. Each ion chamber has a volume of $0.08cm^3$, spacing of 0.762 cm and minimum sampling time of 20 ms. For the investigation of the characteristics, dose linearity, output factor, short-term reproducibility and dose rate dependency were tested. In the testing of dose linearity. It has shown a good signal linearity within 1% in the range of $1{\sim}800$cGy. Dose rate dependency was found to be lower than 0.4% (Range: 100-600 Mu/min) relative to a dose rate of 300 Mu/min as a reference. Output factors matched very well within 0.5% compared with commissioned beam data using a ionization chamber (CC01, Scanditronix-Wellhofer, Schwarzenbruck, Germany) in the range of field sizes $3{\times}3{\sim}24{\times}24cm^2$. Short-term reproducibility (6 times with a interval of 15 minute) was also shown a good agreement within 0.5%, when the temperature and the pressure were corrected by each time of measurement. in addition, we compared enhanced dynamic wedge (EDW, Varian, Palo Alto, USA) profiles from calculated values in the radiation planning system with those from measurements of the MatriXX. Furthermore, anon-uniform IMRT dose fluence was tested. All the comparison studies have shown good agreements. In this study, the MatriXX was evaluated as a reliable dosimeter, and it could be used as a simplistic and convenient tool for radiotherapy qualify assurance.

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Retrospect and Prospect of Medical Law 20th Anniversary (Medical Criminal Law) (의료법학 20주년 회고와 전망(의료형법 분야))

  • Ha, Tae Hoon
    • The Korean Society of Law and Medicine
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    • v.20 no.3
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    • pp.47-79
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    • 2019
  • The Korean Society of Law and Medicine has faithfully played the role of professional academic organizations last 20 years in terms of academic activities, accumulated achievements, diversity, professionalism, and influence on academic circles. The Korean Society of Law and Medicine and the Journal of Medical Law serve as a platform for academic information and exchange of opinions on medical law. Medical law began in the midst of increasing conflicts and disputes caused by medical malpractice and the enactment and legal coercion of medical care as pressure on medical workers. It tried to find a way to coexist with each other through the encounter and convergence of medicine and law. Medical criminal law extends from traditional crimes in the realm of life and body protection to bioethics violations caused by the development of biomedical technology, corruption and economic crime in the medical field. Medical law has evolved into a comprehensive legal area dealing with legal issues raised in medical treatment, healthcare, bioethics, and life sciences technology. On the legal side, medical law is not independent legal areas. It is overlapping with traditional law areas such as civil law, administrative law, criminal law, social law, civil and criminal procedure law. However, it is now established as a convergence study in medicine, bioethics, life science, as well as in various fields of law. It has become an area where collaboration is needed with the field of law, medicine, ethics, sociology and economics. Medical criminal law has undergone a dynamic development over the last two decades. The development of medicine and medical technology provides new and innovative methods of diagnosis and treatment. The achievements and risks of revolutionary developments in biotechnology, genetic engineering and medicine coexist. While there is a dazzling achievement that mankind has hoped for: combating disease and improving health, it also creates unwanted side effects and risks to humans. There is a need to reconsider ethical and legal principles. The discovery and development of patient identity and autonomy has changed the medical doctor-patient relationship. Furthermore, it was complicated by the triangle relationship of patients, medical doctors and insurance. Legal matters are also complicated. This is why the necessity of legislation is emerging. Criminal punishment provisions are also required. The Medical Law and Biomedical Law are systematically and coherently deformed as mosaic-based legislation that takes place whenever there are social issues, citizens' needs, and medical organizations' interests, rather than sufficient enactment and revision procedures. It needs a complete overhaul, and this is possible through interdisciplinary collaboration which is the strength of The Korean Society of Law and Medicine.

An Experimental Study on Time Dependency of Strain for Saturated Clay (포화점토(飽和粘土)의 변형(變形)에 있어서 시간의존성(時間依存性)에 관한 실험적(實驗的) 연구(研究))

  • Park, Byong Kee;Lee, Jin Soo
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.4 no.3
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    • pp.43-52
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    • 1984
  • This paper is concerned with the strain characteristics of the time effect on the remoulded saturated day sampled from the downstream of the Yeongsan river, and the constitutive equation that can generally explain time-dependent behaviors of norma1ly consolidated clay. This paper examines whether or not the afore-said constitutive equation can be applied to the remoulded Mooan-clay. Throughout this study, the conclusions obtained are as follows. 1. Throughout the isotropic consolidation test for 7 days and the isotropic relaxation test, the existence of the static and dynamic yielding surfaces is confirmed respectively. 2. The characteristics of time effect of the deformation, namely, the existence of a unique stress-strain-time relation, is conformed from the experimental result on the Mooan-clay. 3. The prodictions of the stress path and the strain on the Cam-clay theory is not consistent with those observed during the experiments. 4. Constitutive equation(2-3-12) obtained by applying Cam-clay theory to Perzyna's elastic-viscoplasticity theory can explain the behavior of pore water pressure during isotropic stress relaxation, concerned with time dependency under undrained condition. The equation can also explain the results of the undrained triaxial compression test for the clay with different strain rate under the same or different consolidation history. 5. This constitutive equation has eight material parameters which can be determined from triaxial compression tests.

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