• Title/Summary/Keyword: head cross-sectional area

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Comparison of the Cross-Sectional Area of Longus Colli and Muscle Activity of Sternocleidomastoid in Subjects With Forward Head Posture on the Two Craniocervical Flexion Methods

  • Son, Min-chan;Hwang, Ui-jae;Jung, Sung-hoon;Ahn, Sun-hee;Kim, Hyun-a;Kwon, Oh-yun
    • Physical Therapy Korea
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    • v.25 no.2
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    • pp.62-70
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    • 2018
  • Background: The craniocervical flexion (CCF) exercise is one of the effective exercise in correcting forward head posture (FHP). However, some people with FHP achieve CCF with compensatory movements, for example, low cervical flexion using superficial neck flexors such as the sternocleidomastoid (SCM) muscle. No study has yet investigated whether a dual­pres ure biofeedback unit (D-PBU) method to prevent low cervical flexion would be helpful in performing pure CCF movement. Objects: The purpose of this study was to compare the effects of the CCF using D-PBU method and the traditional CCF method on the cross-sectional area (CSA) of the longus colli muscle (LCM) and the activity of SCM muscle in subjects with FHP. Methods: Twenty­four FHP subjects (male: 16, female: 8) were recruited for this study. All subjects performed CCF using two different methods: the traditional CCF method and the CCF using D-PBU method. The CSA of the LCM was measured via ultrasound, and surface electromyography was used to measure SCM muscle activity. Results: The change in CSA of the LCM was significantly larger during the CCF using D-PBU method ($1.28{\pm}.09$) compared with the traditional CCF method ($1.19{\pm}.08$) (p<.05). The SCM muscle activity using the CCF using D-PBU method ($2.01{\pm}1.97$ %MVIC) was significantly lower than when using the traditional CCF method ($2.79{\pm}2.32$ %MVIC) (p<.05). Conclusion: The CCF using D-PBU method can be recommended for increasing LCM activation and decreasing SCM muscle activity during CCF movement in subjects with FHP.

A Numerical Study on the Effect of Volute Geometry on the Performance of Centrifugal Pump (볼류트 형상이 원심 펌프의 성능에 미치는 영향에 대한 수치 해석적 연구)

  • Kim, Deok-Su;Jeon, Sang-Gyu;Yoon, Joon-Yong;Choi, Young-Seok
    • The KSFM Journal of Fluid Machinery
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    • v.9 no.2 s.35
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    • pp.44-49
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    • 2006
  • In this study, the effects of volute area distribution on the performance of a centrifugal pump were numerically studied using a commercial CFD code. To reduce the shutoff head, maintaining head and efficiency at a design flow rate, the flat head-capacity characteristic curves in which the head varies only slightly with capacity from shutoff to design capacity are frequently required. In order to control the shutoff head of a pump, several volute cross-sectional area distributions were proposed as a main parameter with the same impeller geometry The calculation results show that the slope of the performance characteristic curve of the centrifugal pump can be controlled by modifying the area distribution from volute tongue to volute outlet with fixed volute outlet area and also varied volute outlet area.

A Numerical Study on the effect of Volute Geometry on the Performance of Centrifugal Pump (볼류트 형상이 원심 펌프의 성능에 미치는 영향에 대한 수치 해석적 연구)

  • Kim, Deok-Su;Choi, Young-Seok;Jeon, Sang-Gyu;Yoon, Joon-Yong
    • 유체기계공업학회:학술대회논문집
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    • 2005.12a
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    • pp.497-502
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    • 2005
  • In this study. the effect of volute area distribution on the performance of a centrifugal pump were numerically studied using a commercial CFD code. To reduce the shutoff head, maintaining head and efficiency at a design flow rate. the flat head-capacity characteristic curves in which the head varies only slightly with capacity from shutoff to design capacity are frequently required. In order to control the shutoff head of a pump, several volute cross-sectional area distributions were proposed as a main parameter with the same impeller geometry. The calculation results show that the slope of the performance characteristic curve of the centrifugal pump can be controlled by modifying the area distribution from volute tongue to volute outlet with fixed volute outlet area and also varied volute outlet area.

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Treatment Outcomes of Septoplasty with Turbinate Surgery in Septal Deviation with Chronic Hypertrophic Rhinitis (비중격 만곡증 및 만성 비후성 비염 환자에서 비중격 성형술고 하비갑개 수술의 치료효과)

  • Kim, Yong-Dae;Suh, Bo-Su;Cho, Gil-Sung;Song, Si-Youn;Yoon, Seok-Keun;Song, Kei-Won
    • Journal of Yeungnam Medical Science
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    • v.18 no.2
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    • pp.199-207
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    • 2001
  • Background: Septoplasty with turbinate surgery is common surgical treatment in patients with septal deviation and chronic hypertrophic rhinitis. The aim of this study was to evaluation objective outcomes of septoplasty with turbinate surgery by analysis of subjective symptom score with objective acoustic rhinometric test before and after surgery, prospectively. Materials and Methods: We reviewed 45 adult patients which were done septoplasty with bilateral turbinectomy or turbinoplasty and followed up at least 3 months by one rhinologist from November 1999 to April 2000, prospectively. We analyzed subjective symptom score, minimal cross-sectional area (MCA), C-notch cross-sectional area, and total volume of both nasal cavity before and after surgery. Correlation test was studied between symptom improvement and acoustic rhinometric results. Results: Twenty nine cases were male and sixteen cases female. The average age was 26.9 year-old (range: 17 to 57 years). There was significantly improvement of symptom score in postoperative 3 months (p<0.05). There was significantly increased C-notch cross-sectional area and total volume in postoperative 3 months. Symptoms improvement were associated with acoustic rhinometric profiles, but, there was not significantly correlation. Conclusion: Septoplasty with turbinate surgery is considered to be effective for nasal obstruction in patients with septal deviation and turbinate hypertrophy. Acoustic rhinometric test is favorable objective test for evaluation of symptom improvement after septal surgery.

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Hydraulic Computation and Stress Analysis of Box Culvert (암거의 수리 및 응력계산)

  • 함준호
    • Magazine of the Korean Society of Agricultural Engineers
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    • v.14 no.1
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    • pp.2557-2569
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    • 1972
  • Hydraulic computations to determine the elevation of canal bottom and mater surface for box type concrete culverts are discussed. Velocity and cross sectional area of flow are computed from Manning's formula. Aad then head loss and velocity head are considered to determine the elevation of bottom and water surface. For stress analysis, 13.5 ton live load and earth pressure are considered. Also longitudinal stress of box culverts is checked.

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Conductivity Imaging of a Canine Head using a 3T MREIT System with a Carbon-Hydrogel Electrode: Postmortem Experiment (3T MREIT 시스템을 이용한 실험견 사체의 두부 도전율 영상)

  • Jeong, Woo-Chul;Kim, Young-Tae;Minhas, Atul S.;Kim, Hyung-Joong;Lee, Tae-Hwi;Kang, Byeong-Teck;Park, Hee-Myung;Woo, Eung-Je
    • Journal of Biomedical Engineering Research
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    • v.30 no.2
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    • pp.179-184
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    • 2009
  • Magnetic Resonance Electrical Impedance Tomography (MREIT) is a new bio-imaging modality providing cross-sectional conductivity images from measurements of internal magnetic flux densities produced by externally injected currents. Recent MREIT studies demonstrated successful conductivity image reconstructions of postmortem and in vivo canine brain. However, the whole head imaging was not achieved due to technical issues related with electrodes and noise in measured magnetic flux density data. In this study, we used a new carbon-hydrogel electrode with a large contact area and injected 30 mA imaging current through a canine head. Using a 3T MREIT system, we performed a postmortem canine experiment and produced high-resolution conductivity images of the entire canine head. Collecting magnetic flux density data inside the head subject to multiple injection currents, we reconstructed cross-sectional conductivity images using the harmonic $B_z$ algorithm. The conductivity images of the canine head show a good contrast not only inside the brain region including white and gray matter but also outside the brain region including the skull, temporalis muscle, mandible, lingualis proprius muscle, and masseter muscle.

Correlations Between Maximal Isometric Strength and the Cross-Sectional Area of Lumbrical Muscles in the Hand

  • Jung, Doh-Heon;Lee, Won-Hwee;Kim, Su-Jung;Cynn, Heon-Seock
    • Physical Therapy Korea
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    • v.18 no.4
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    • pp.34-42
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    • 2011
  • The lumbrical muscles contribute to the intrinsic plus position, that is simultaneous metacarpophalangeal (MCP) flexion and interphalangeal (IP) extension. The strength of the lumbrical muscles is necessary for normal hand function. However, there is no objective and efficient method of strength measurement for the lumbrical muscles. In addition, previous studies have not investigated the measurement of the cross-sectional area (CSA) of the lumbrical muscles using ultrasonography (US) and the relationship between lumbrical muscle strength in the intrinsic plus position and the CSA. Therefore, the purpose of this study was to identify the measurement method of the CSA of the lumbrical muscles using US and to examine the relationship between maximal isometric strength and the CSA of lumbrical muscles. Nine healthy males participated in this study. Maximal isometric strength of the second, third, and fourth lumbrical muscles was assessed using a tensiometer in the intrinsic plus position which isolated MCP flexion and IP extension. The CSA of the lumbrical muscles was measured with an US. The US probe was applied on the palmar aspect of the metacarpal head with a transverse view of the hand in resting position. There was no significant difference between maximal isometric strength of the lumbrical muscles, but the fourth lumbrical muscle was stronger than the others. The CSA of the lumbrical muscles was significantly different and the fourth lumbrical muscle was significantly larger than the second lumbrical muscle. There was moderate to good correlation between maximal isometric strength and the CSA of the lumbrical muscles. Therefore, we conclude that maximal isometric strength of the lumbrical muscles was positively correlated to the CSA of the lumbrical muscle in each finger, while the measurement of the CSA of the lumbrical muscles, using US protocol in this study, was useful for measuring the CSA of the lumbrical muscles.

Fabrication of wide-head T-gate with 0.2 ${\mu}{\textrm}{m}$ gate length using E-beam lithography for MIMIC applications. (전자선 묘화를 이용한 0.2 ${\mu}{\textrm}{m}$의 게이트 길이를 갖는 MIMIC용 Wide-Head T-gate 제작)

  • 전병철;박덕수;신재완;양성환;박현창;이진구
    • Proceedings of the IEEK Conference
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    • 1999.11a
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    • pp.187-190
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    • 1999
  • We have developed fabrication processes that form a wide-head T-gate with a 0.2 ${\mu}{\textrm}{m}$ gate length using the combination of thickness of each PMMA layer, line doses and development times for applications in millimeter- and micro-waves monolithic integrated circuits. The three-layer resist structure (PMMA/P(MMA-MAA)/PMMA = 1800 $\AA$/5800 A/1900$\AA$), 4nC/cm and over development were used for fabrication of a wide-head T-gate by the conventional double E-beam exposure technology. The experimented results show that the cross sectional area of T-gate fabricated by the proposed method is easily enlarged without additional processes.

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Analysis of Internal Overpressure by Pipe Cross-Sectional Area Ratio and Filling Rate in the Hydraulic Test of Shipboard Tank (수압시험 시 관 단면적 비 및 충수 속도별 탱크 내부 과압 발생에 관한 해석)

  • Geun-Gon Kim;Tak-Kee Lee
    • Journal of the Society of Naval Architects of Korea
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    • v.60 no.6
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    • pp.460-472
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    • 2023
  • This study was conducted based on the case of an accident (excessive deformation) that occurred during the hydraulic test of a shipboard tank manufactured in accordance with the design regulations. Over-pressure phenomenon was noted as the main cause of accidents in the process of testing tanks without physical damage, which can be found in external factors such as cross-sectional difference between inlet pipe and air pipe and higher water filling rate than the recommended one. The main goal of this paper is to establish a safe water filling rate according to the range of sectional area ratio(SAR) reduced below the regulations for each test situation. The simulation was conducted in accordance with the hydraulic test procedure specified in the Ship Safety Act, and the main situation was divided into two types: filling the tank with water and increasing the water head to the test pressure. The structural safety evaluation of the pressure generated inside the tank and the effect on the structure during the test was reviewed according to the SAR range. Based on the results, guidelines for the optimal filling rate applicable according to SAR during the hydraulic test were presented for the shipboard tanks used in this study.

The Effect of Partial Blockage of Flow Passage to Performance Change of a Liquid Rocket Engine (유로 단면 부분 폐쇄가 액체로켓엔진 성능 변화에 미치는 영향)

  • Cho, Won Kook
    • Journal of Aerospace System Engineering
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    • v.9 no.4
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    • pp.67-72
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    • 2015
  • The analysis has been performed on the blockage effect at the propellant flow passage in a liquid rocket engine. This simulates an example of emergency situation where flow passage is partially blocked. The analysis method has been validated by predicting the pump head and flow rate within 1% precision against the measured data of turbopump-gas generator coupled test. When the oxidizer passage is reduced it is predicted that the mixture ratio decreases, the oxidizer pump head increases and the gas generator pressure increases. When the fuel passage is reduced it is predicted that the mixture ratio increases, fuel flow rate decreases and the fuel pump head increases.