• 제목/요약/키워드: Stability and stabilization

검색결과 884건 처리시간 0.027초

Experimental Study on Laminar Lifted Methane Jet Flame Diluted with Nitrogen and Helium

  • Sapkal, Narayan;Lee, Won June;Park, Jeong;Kwon, Oh Boomg
    • 한국연소학회:학술대회논문집
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    • 한국연소학회 2014년도 제49회 KOSCO SYMPOSIUM 초록집
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    • pp.387-389
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    • 2014
  • Laminar lifted methane jet flame diluted with nitrogen and helium in co-flow air has been investigated experimentally. This paper examines the role of chemistry, intermediate species responsible for stabilization of lifted flame. To elucidate the stabilization mechanism in lifted methane jet flames with Sc<1, the chemiluminescence intensities of $CH^*$ and $OH^*$ were measured using ICCD camera at various nozzle exit velocities and fuel mole fractions. It has been observed that the $OH^*$ species can play an important role in stabilization of lifted methane jet flame as they are good indicators of heat release rate which can affect on flame speed and increase stability through reduction in ignition delay time.

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Experimental Study on Laminar Lifted Methane Jet Flame Diluted with Nitrogen and Helium

  • Sapkal, Narayan;Lee, Won June;Park, Jeong;Kwon, Oh Boomg
    • 한국연소학회:학술대회논문집
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    • 한국연소학회 2014년도 제49회 KOSCO SYMPOSIUM 초록집
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    • pp.125-128
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    • 2014
  • Laminar lifted methane jet flame diluted with nitrogen and helium in co-flow air has been investigated experimentally. This paper examines the role of chemistry, intermediate species responsible for stabilization of lifted flame. To elucidate the stabilization mechanism in lifted methane jet flames with Sc<1, the chemiluminescence intensities of $CH^*$ and $OH^*$ were measured using ICCD camera at various nozzle exit velocities and fuel mole fractions. It has been observed that the $OH^*$ species can play an important role in stabilization of lifted methane jet flame as they are good indicators of heat release rate which can affect on flame speed and increase stability through reduction in ignition delay time.

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체간 안정화 운동과 고관절 운동이 만성 요통 환자의 허리가동범위, 통증, 장애정도에 미치는 영향 (Effects of Trunk Stability Exercise and Hip Exercise on Lumbar Range of Motion, VAS, Disability Chronic Low Back Pain Patients)

  • 박찬호;양영식;정용식
    • 대한정형도수물리치료학회지
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    • 제28권2호
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    • pp.45-55
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    • 2022
  • Background: This study compared the effects of trunk stabilization exercise and hip joint exercises on the range of motion of the lumbar spine, pain severity, and severity of disability in patients with chronic lower back pain. Methods: A total of 30 participants were enrolled and divided into group 1 (n=10), group 2 (n=10), and group 3 (n=10) were performed by each group thrice a week for a total of 8 weeks. Group 1 performed warm-up exercise (15 min), trunk stabilization exercise (25 min), finish-up exercise (15mins). Group 2 performed warm-up exercise (15 min), hip exercise (25 mins, finish-up exercise (15mins). Group 3 warm-up exercise (15 min), trunk stabilization and hip exercise (25 min), Finish-up exercise (15 min). Participants were assessed for the range of motion of the lumbar spine, pain severity (visual analog scale score; VAS), and severity of disability (Oswestry disability index score; ODI) before and after the interventions. Results: All three groups showed a significant increase in the range of motion of the lumbar spine, but there was no significant difference among the groups. Moreover, the severity of pain and ODI were significantly decreased in all groups; however, the intergroup differences were non-significant. Conclusion: The results from this study confirmed the effectiveness of trunk stabilization and hip joint exercise in improving the lumbar range of motion, pain severity, and chronic lower back pain in patients. Thus, trunk and pelvic stabilization exercises and hip joint exercise can be used as clinical practices to treat and prevent chronic lower back pain.

앞쪽머리자세가 있는 만성 목통증 환자에게 압력 바이오피드백 장비를 이용한 목안정화운동 적용이 목통증과 앞쪽머리자세, 음향학적 특성 변화에 미치는 효과 (Effects of Cervical Stabilization Exercise Using Pressure Biofeedback on Neck Pain, Forward Head Posture and Acoustic Characteristics of Chronic Neck Pain Patients with Forward Head Posture)

  • 김기철;황보필녀
    • 대한물리의학회지
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    • 제14권1호
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    • pp.121-129
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    • 2019
  • PURPOSE: This study was conducted to measure the effects of cervical stabilization exercises on neck pain, forward head posture, and the acoustic characteristics frequency and amplitude modulation of patients with chronic neck pain caused by forward head posture using pressure biofeedback. METHODS: 20 patients with chronic neck pain and voice disorders presenting at the S Exercise Center in Daegu, Korea, were included in the study. A cervical stabilization exercise program of 50 minutes per session was performed three times a week for eight weeks. Pressure biofeedback was utilized to determine the impact of the exercises on neck pain, forward head posture, and the acoustic characteristics of the patients. The measurements were taken prior to and after the intervention to determine any changes. RESULTS: A significant improvement in neck pain, craniovertebral angle and the acoustic characteristics frequency and amplitude modulation of the patients was demonstrated after the intervention (p<.05). CONCLUSION: Cervical stabilization exercises were demonstrated to have a significantly positive effect on neck pain, forward head posture, and vocalization stability in patients with chronic neck pain in the current study based on measurements taken using a pressure biofeedback system. This indicates that an improvement in forward head posture positively impacts postural stability and vocalization. Future studies investigating a greater range of interventions designed to improve neck pain and acoustical effects in patients with chronic neck pain and forward head posture patients are warranted.

수산업관측사업의 가격안정화 효과 분석 (Price Stabilization Effect of the Fisheries Outlook Project)

  • 이상호;정원호
    • 수산경영론집
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    • 제53권4호
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    • pp.15-26
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    • 2022
  • This paper analyzed the price stabilization before and after the fisheries outlook project for seaweed, flatfish, and abalone. First, the stabilization effect was analyzed through the price variation coefficient before and after the observation project. In terms of the variation coefficient, there was no effect that the price was stabilized through the seaweed outlook project. However, it can be seen that flatfish and abalone have a price-stabilizing effect. Second, as a result of analyzing the price stabilization effect through the improved ARMA-T-GARCH model, it was confirmed that seaweed was not statistically significant while flatfish and abalone had a price stabilization effect by statistically significantly reducing volatility of real prices after the introduction of the fisheries outlook project. Third, as a result of analyzing the factors affecting price stability, it was found that the price of seaweed was stabilized after the WTO, but the Japanese earthquake expanded the price volatility. In the case of flatfish, it was analyzed that the price stabilized after the WTO and the Great Japanese Earthquake. Finally, the price of abalone has stabilized since the WTO and the Great Japanese Earthquake.

Effects of Sling Bridge Exercise with Rhythmic Stabilization Technique on Trunk Muscle Endurance and Flexibility in Adolescents with Low Back Pain

  • Kim, Kyung-Yoon;Sim, Ki-Chol;Kim, Tae-Gon;Bae, Sea-Hyun;Lee, Jun-Cheol;Kim, Gi-Do
    • International Journal of Contents
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    • 제9권4호
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    • pp.72-77
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    • 2013
  • The purpose of this study was to examine the effects of general sling-bridge exercise (GSE) and sling-bridge exercise with rhythmic stabilization technique (SER) on trunk muscle endurance and flexibility in adolescents with low back pain (LBP). 30 adolescents who had complaints of LBP were randomly assigned to one of the two groups: the GSE group (n=15) and SER group (n=15). Subjects performed each exercise programs for 4 weeks with the aim of improving trunk muscle stability; GSE group trained general bridge exercise with sling, SER group trained rhythmic stabilization bridge exercise with sling. The static and dynamic trunk muscle endurance and flexibility were measured before and at the end of the exercise program. The static and dynamic trunk muscle endurance were significantly improved in both groups (p<.05) and the SER group showed significant difference from the GSE group after the exercise (p<.05). The trunk muscle flexibility was significantly improved in both groups (p<.05) and the SER group were significantly different from GSE group post-exercise (p<.05). The results of this study showed that sling bridge exercise with rhythmic stabilization technique may be appropriate for improving trunk muscle stability in adolescents with LBP.

스위스 볼을 이용한 체간 안정화 운동과 코어 안정화 운동이 여성노인의 균형과 보행에 미치는 영향 (The Effects of Trunk Stabilization Exercise Using Swiss Ball and Core Stabilization Exercise on Balance and Gait in Elderly Women)

  • 최수희;임재헌;조화영;김일복;김모경;이현영
    • 대한물리의학회지
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    • 제7권1호
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    • pp.49-58
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    • 2012
  • Purpose : The purpose of this study was to investigate the effects of trunk stabilization exercise using swiss ball and core stabilization exercise on balance and gait in elderly women. Methods : Subjects 19 elderly women were randomly divided by the swiss ball exercise group (n=10) and the core stabilization exercise group (n=9). In a period of 4 weeks, they took trunk stabilization exercise using swiss ball and core stabilization exercise for 60 minutes 3 times a week. Balance and gait were measured by Functional Reach Test (FRT), One Leg Stand Test with Open Eye (OLSTOE), One Leg Stand Test with Closed Eye (OLSTCE), Timed Up and Go Test (TUG) and 6 m Walking Test (6MWT). These tests were measured at before exercise, 4 weeks after exercise and after the follow-up period of 2 weeks. Results : As a result, in all measurement values there was no significant difference in two groups (p>.05). In FRT, TUG, OLSTOE and 6MWT before exercise and 4 weeks after exercise, there was significant difference in both of two groups (p<.05). Moreover, according to results from 4 weeks after exercise and after the follow-up period of 2 weeks, without any particular exercise, in FRT and 6MWT there was no significant difference (p>.05). Conclusion : These finding indicate that trunk stabilization exercise using swiss ball could improve balance and gait in elderly women. Accordingly, In this study trunk stabilization exercise using swiss ball and core stabilization exercise is judged to be used for elderly people with gait and balance problems to prevent hurts from fall.

상태변수에 지연요소를 갖는 시스템의 안정화 방법에 관한 연구 (Feedback stabilization of linear systems with delay in state)

  • 권욱현;임동진
    • 전기의세계
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    • 제31권1호
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    • pp.59-67
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    • 1982
  • This paper suggests easy stabilization methods for linear time-varying systems with delay in the state. While existing methods employ the function space concept, the methods introduced in this paper transform the delay systems into the non-delay systems so that the well known methods for finite dimensional systems can be utilized. Particularly the intervalwise predictor is introduced and shown to satisfy an ordinary system. Control laws stabilizing the non-delay systems satisfied by this predictor will be shown to at least pointwise stabilize the delay systems with the additional strong possibility of true stabilization. In order to combine two steps of the predictor method, first transformation and then stabilization, an intervalwise regulator problem is suggested whose optimal control laws incorporate the intervalwise predictor as an integral part and also at least pointwise stabilize the delay systems. Since the above mentioned methods render the periodic feedback gains for time invariant systems the pointwise predictor and regulator are introduced in order to obtain the constant feedback gains, with additional stability properties. The control laws given in this paper are perhaps simplest and easiest to implement.

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폴리에스터용 잉크젯 잉크의 분산안정성 개선에 관한 연구 (Improvement of Dispersion Stability of Ink-jet Ink for Polyester Fiber)

  • 최재홍;지병철;서인석
    • 한국염색가공학회지
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    • 제15권5호
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    • pp.321-326
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    • 2003
  • In order for disperse dye based ink to be fitted with the critical requirements of ink jet printing, this study was undertaken to investigate the effects of 6 different dispersants on the milling efficiency of insoluble dye particles and dispersion stability of the final ink. It was found that a polystyrene dispersant with high molecular weight exerted relatively better dispersion stability which may be associated with its steric stabilization effect in the ink solution.

무릎관절 전치환술 환자에게 적용한 무릎 안정화 운동이 균형과 보행능력에 미치는 영향 (Effect of Knee Stabilization Exercise on Balance and Walking Ability in Patients with Total Knee Replacement)

  • 박근홍;김태원;송형봉
    • 대한정형도수물리치료학회지
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    • 제27권2호
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    • pp.69-76
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    • 2021
  • Background: Degenerative arthritis accounts for a large portion of the elderly, causing a lot of inconvenience in daily life. Total knee replacement (TKR) are performed to relieve pain in the knee joint. The purpose of this study was to determine whether knee joint stabilization exercises are effective in improving balance and walking ability in degenerative arthritis patients who have undergone TKR. Methods: A total of 30 TKR patients participated in this study. They were assigned to two groups. The experimental group, the group that underwent knee stabilization exercises, joint mobilization and general physical therapy. On the other hand, and the controlled group, the group that underwent joint mobilization and general physical therapy. All exercises were conducted thrice a week, for four weeks. The main balance outcomes were evaluated using the posture balance training system, while walking ability was assessed using a wireless 3-axis accelerometer. Results: The experimental group had significantly higher scores in postural stability testing (PST), limits stability testing, and waling ability. The post-intervention evaluation, there were significant differences in all variables between the two groups. However, no significant difference was noted in the foam eyes closed test in PST. Conclusion: This study suggests that knee joint stabilization exercises effectively improve the balance and walking ability of TKR patients. Thus, it could be presented as useful in clinical practice.