• 제목/요약/키워드: stabilization of pressure

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HYLGS 모델을 활용한 수도권 매립지에서의 침출수-가스의 동시유동 해석에 관한 연구

  • 이광희;박용찬;성원모
    • Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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    • 1998.11a
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    • pp.225-231
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    • 1998
  • Open dump causes groundwater and soil contamination by leachate, air pollution by LFG (Landfill Gas). In this paper, in order to improve landfill researches which have been done about reduction of high leachate level and LFG collection in the Kimpo landfill separately, the effect of simultaneous flowing of leachate and LFG has been Studied. The HYLGS (Hanyang Leachate Gas Simulator) used in this study is a 3D, 2-phase, transient FDM model which can be applied to venting trenches in a landfill. From present numerical analysis it can be concluded that all the pressures of the Kimpo landfill grid system are almost the same and their maximum value in the center grid block of the system is approximately 26 m $H_2O$ (2.52 atm), that because the pressures of venting trench layer situated in the middle of the landfill have the lowest values and equal with air pressure, the venting trenches play an important role in landfill stabilization, that the flow of gas will be more difficult as time goes by owing to the increase of LGR(Leachate and gas ratio).

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Effect of ischemic preconditioning on left ventricular function after cardiac arrest in isoated rat heart (적출 쥐 심장에서 허혈성 전조건화가 심정지후 좌심실 기능에 미치는 영향)

  • 조대윤
    • Journal of Chest Surgery
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    • v.27 no.7
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    • pp.563-570
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    • 1994
  • Effect of ischemic preconditioning on left ventricular function after cardiac arrest in isolated rat heart.Ischemic preconditioning reduces infarct size caused by sustained ischemia. However, the effects of preconditioning on post ischemic cardiac function are not well-known. The objective of the present study was to determine whether preconditioning would improve the recovery of left ventricular functions after cardiac arrest in isolated rat heart model.Isolated rat hearts were allowed to equilibrate for 20 minutes and were then subjected to either 5 minutes of global, normothermic transient ischemia [Group 2 and 4] or not [Group 3]. A stabilization period of perfusion lasting 5 minutes after the termination of transient ischemia was followed by a standard global, normothermic 20 minute-ischemia and 35-minute reperfusion challenge [Group 3 and 4]. These following results were odtained.1. The recovery of left ventricular developed pressures showed no significant differences between Group 3 and Group 4 at 50 [P>0.3] and 85 minute [P>0.2].2. Heart rates showed no significant differences throughout all the course of experiment and between groups [P>0.5].3. The recovery of left ventricular maximum dP/dt showed no significant differences between Group 3 and Group 4 at 50 [P>0.1] and 85 minute [P>0.2].4. The recovery of pressure-rate products showed no significant differences between Group3 and Group 4 at 50 [P>0.5] and 85 minute [P>0.1].These results suggest that ischemic preconditioning does not provide significant benefit for the postischemic left ventricular functions in isolated rat hearts.

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Comparing the Effects on Elderly Women of Bearing Weights and Lumbar Stabilization Using Lumbar Muscle Exercises-Group vs. Individual Sessions with a Physical Therapist (여성 노인에서 집단과 개별 요부 운동이 요부 안정화 및 체중 부하에 미치는 효과)

  • You, Young-Youl;Kim, Hee-Soo
    • The Journal of Korean Physical Therapy
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    • v.22 no.5
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    • pp.17-23
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    • 2010
  • Purpose: The purpose of this study was to compare the effects, in elderly women, of (a) physical therapy with (b) individual and group lumbar muscle exercise Methods: Forty-two elderly women took part in this study. Their average age was 52.59 years. All subjects participated in the study for 8 weeks, doing exercises 3 days per week. All participants were assessed on the Oswestry disability index (ODI), Gaitview. The data were analyzed using paired t-tests. Results: Foot pressure and ODI scores showed statistically significant pre- to post-exercise differences for both groups. We also found significant differences between group therapy and individual therapy. There were changes in mean ODI scores, but these were not significant. Conclusion: Eight weeks participation in an was found to be effective in improving the health of older women. Individual therapy with a physical therapist is more effective than group therapy in creating harmonious movement of the lower extremity and lumbar stability. The results of our study suggests the benefit of an exercise program with a physical therapist.

Effects of Bridging Exercise using Vibration Stimulation and ADIMs on the Lengthening and Thickness of Transversus Abdominis in Healthy Adults

  • Kong, Kwan-Woo
    • The Journal of Korean Physical Therapy
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    • v.28 no.6
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    • pp.393-397
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    • 2016
  • Purpose: This study was conducted in an effort to determine the effects of various abdominal drawing-in maneuver (ADIM) on the thickness and length of the transversus abdominis (TrA) when using lumbar stabilization exercises on healthy adults. Methods: 72 healthy adults were divided into four groups of 18 subjects each, to which different ADIM methods were applied. 1) a simple ADIM exercise, 2) an ADIM with pressure bio-feedback units, 3) an ADIM exercise with sling, and 4) an ADIM exercise with sling and vibration. Changes in the thickness and sliding length of TrA were measured when ADIM was conducted in the supine position prior to exercise and again when beginning the exercises. Following exercise, changes in the thickness and sliding length of TrA were measured using the same methods. Differences in group measurements prior to and following exercise were compared using a one-way analysis of variance. A paired t-test was applied to compare the before and after differences within each group. Results: Differences in TrA thickness change revealed that the ADIM exercise with sling and vibration group showed a significant difference in measurements taken prior to and following exercise. Differences in TrA length change revealed that the ADIM exercise with sling and vibration group showed a significant difference in measurements taken prior to and following exercise. Conclusion: ADIM exercise with vibration stimulation conducted in the bridge posture while in a prone position using a sling can be recommended as an effective exercise to improve the function of lumbar TrA.

Architectural Planning Study on Spatial Composition of Mobile Seclusion Module - Based on Modular Construction System (이동형 안정실 모듈의 공간구성에 대한 건축계획적 연구 - 모듈러 건축 공법을 기반으로)

  • Kim, Sung Hyun;Yang, Nae-won
    • Journal of The Korea Institute of Healthcare Architecture
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    • v.29 no.2
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    • pp.49-60
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    • 2023
  • Purpose: This study aims to establish detailed spatial planning by identifying the needs for a seclusion module for emergency psychiatric patients. Methods: The necessity of medical space with seclusion function was analyzed from spatial, medical, and social perspectives. The needs for a space capable of performing three medical functions: protection, isolation, and treatment, was analyzed. Among various types of mobile medical facilities, seclusion space was considered suitable for utilizing modular construction methods, as it is the most rational method that can satisfy the environmental level of fixed healthcare facilities' space. Therefore, seclusion modules based on modular construction were planned, consisting of two protective units for stabilizing patients with psychiatric illness, one for treatment unit that can accommodate both internal and external treatment, and another one for an infectious disease isolation unit equipped with negative pressure equipment. Implications: This study analyzed the necessary medical functions of the interior space of the mobile stabilization module based on the spatial analysis of existing medical facilities, and proposed alternative spatial configurations according to treatment, seclusion, isolation functions.

PID Control of a Synchronous Rotor System Vibration with Active Air Bearing (능동 공기 베어링에 의한 로터계 동기진동의 PID제어)

  • Gwon, Dae-Gyu;Lee, Yeong-Chun;Lee, Seong-Cheol
    • Journal of the Korean Society for Precision Engineering
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    • v.18 no.8
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    • pp.32-39
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    • 2001
  • This paper presents the synchronous vibration control of a rotor system using an Active Air Bearing(AAB). In order to suppress the synchronous vibration, it is necessary to actively control the air film pressure or the air film thickness. In this study, active pads are used to control the air film thickness. Active pads are supported by the pivots containing piezoelectric actuators and their radial positions can be actively controlled by applying voltage to the actuators. Disturbances and various kinds of external force can cause the shaft vibration as well as the change of the air film thickness. The dynamic behaviors of a rotary system supported by two tilting-pad gas bearings and its active stabilization using the tilting-pads as actuators are investigated numerically. The PID controller is applied to the tilting-pad gas bearing system with three pads, two of which contain piezoelectric actuators. To test the vapidity of the theoretical method, the performance of this control method is evaluated through experiments. The experimental results show the effectiveness of the control system for suppressing the unbalanced response of the rigid modes.

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The Effects of Cervical Extension-Traction Exercise on Cervical Alignment, Pain, and Neck Disability in Patients with Mild Turtle Syndrome (경추 신전-견인 운동이 경증 거북목증후군 환자의 경추정렬, 통증, 기능장애에 미치는 영향)

  • Han, Hyo-jin;Lee, Jae-nam;Hyun, Ki-hoon;Yang, Young-sik
    • The Journal of Korean Academy of Orthopedic Manual Physical Therapy
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    • v.25 no.2
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    • pp.1-10
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    • 2019
  • Background: The purpose of this study was to determine the effects of cervical extension-traction exercise on cervical alignment, pain, and neck disability in patients with mild turtle syndrome. Methods: Thirty two outpatients with mild turtle neck syndrome were recruited and randomly divided into two groups. Participants in the experimental group was applied cervical extension-traction exercise (CETE, n=16) and in the control group applied cervical stabilization exercise (CSE, n=16) for three times a week for 4 weeks. Results: Cobb angle and Jochumsen depth were CETE showed significant difference within the group post test (p<.05). And the CETE was significantly higher than the CSE. In the pressure pain threshold, both CETE and CSE showed significant differences within post test (p<.05). And the CETE was significantly higher than the CSE. Neck disability index were significant (p<.05) in the CETE post test. There was no significant difference between the two groups. Conclusion: Our results of this study showed that applying cervical extension-traction exercise to patients with mild turtle syndrome improved cervical alignment, pain and neck dysfunction.

The safety behavior of agricultural reservoirs due to raising the embankment

  • Lee, Dalwon;Lee, Younghak
    • Korean Journal of Agricultural Science
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    • v.40 no.3
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    • pp.243-252
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    • 2013
  • This study was carried out to investigate safety evaluation of agricultural reservoirs due to raising the embankment. The seepage analysis and large-scale model test were performed to compare and analyze the pore water pressure(PWP), leakage quantity, settlement and piping phenomenon in the inclined core type and the vertical core type embankments. The PWP after raising the embankment showed smaller than before raising the embankment and the stability for piping after raising the embankment. The allowable seepage quantity and the allowable leakage for the steady state and transient conditions is within the range of safe management standard. After raising the embankment in the inclined core, there was no infiltration by leakage. For the vertical core, the PWP showed a large change by faster infiltration of pore water than in the inclined core. In a rapid drawdown, inclined core was remained stable but the vertical core showed a large change in PWP. Settlement after raising the embankment showed larger amounts of settlement than before raising the embankment. The leakage quantity before raising the embankment and the inclined core type showed no leakage. From the result, an instrument system that can accurately estimate a change of PWP shall be established for the rational maintenance and stabilization of raising the embankment for agricultural reservoirs.

An Experimental Study on Optimum Design of Half-Wave Resonators for Combustion Stabilization (연소 불안정 억제를 위한 반파장 공명기 최적 설계 조건에 대한 실험적 연구)

  • Park, Ju-Hyun;Sohn, Chae-Hoon
    • Proceedings of the Korean Society of Propulsion Engineers Conference
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    • 2008.11a
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    • pp.11-14
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    • 2008
  • Acoustic design parameters of a half-wave resonator are studied experimentally for acoustic stability in a model acoustic tube. According to standard acoustic-test procedures, acoustic-pressure signals are measured. Quantitative acoustic properties of sound absorption coefficient are evaluated and thereby, the acoustic damping capacity of the resonator is characterized. The diameter and the number of a half-wave resonator and the diameter of the tube are selected as design parameters for optimal tuning of the resonator. Optimum acoustic damping capacity is observed at smaller open area ratio as the resonator diameter increases.

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The Correlation of Hip Abductor, Adductor and Abdominis, Low Limb Muscle Activation During Bridging Exercise with Hip Abductor and Adductor Contraction (고관절 내.외전근 수축을 이용한 교각 운동에서의 내.외전근과 복부 및 하지근육과의 상관관계 연구)

  • Lee, Sang-Yeol
    • Journal of the Korean Society of Physical Medicine
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    • v.7 no.2
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    • pp.199-203
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    • 2012
  • Purpose : Bridging exercise was used most frequently of lumbar stabilization exercise. There has been no reserch regarding the bridging exercise according to hip abductor activation or hip adductor activation. The purpose of this study is to determine correlation of hip abductor, adductor and abdominal muscles, lower limb muscle. Methods : Participants who met the criteria for this study (n=45). Participants performs bridging exercise on three types (normal bridging exercise, bridging exercise with hip abductor contraction, bridging exercise with hip adductor contraction) for evaluate correlation of each muscles. Results : There was a significant negative correlation between adductor magnus and gluteus medius, adductor magnus and rectus femoris. And there was a positive correlation between gluteus medius and rectus femoris on normal bridging exercise (p<0.05). There was a significant positive correlation between adductor magnus and gluteus medius, transverse abdominis, and between gulteus medius and transverse abdominis on bridging exercise with adductor magnus activation (p<0.05). There was a significant positive correlation between adductor magnus and gluteus medius, rectus femoris, and between gulteus medius and rectus femoris on bridging exercise with gluteus medius activation (p<0.05). Conclusion : When we perform bridging exercise for transverse abdominis activation and increase pressure in the abdmen, bridging exercise with hip adductor contraction is more effective than normal bridging exercise and bridging exercise with hip abductor contraction.