• Title/Summary/Keyword: contraction rate

Search Result 342, Processing Time 0.029 seconds

Flow-Induced Birefringence of Polymers in the Region of Abrupt Thickness Transition (두께가 급격히 변하는 영역에서 고분자 유동에 의한 복굴절)

  • Lee, H.S.;Isayev, A.I.
    • Transactions of Materials Processing
    • /
    • v.18 no.1
    • /
    • pp.20-25
    • /
    • 2009
  • A finite element analysis was carried out for a 4:1 planar contraction die for polymer melts using the viscoelastic constitutive equation of Leonov. Viscoelastic fluids showed significant differences in pressure drop and birefringence in contraction and expansion flows. The pressure drop was higher and the birefringence smaller in expansion than in contraction flow. The difference increased with increasing flow rate. The nonlinear Leonov model was shown to describe the viscoelastic effects observed in experiments.

Change of the Maximal Isometric Contraction to the Spastic Muscle by NMES (신경근전기자극에 의한 경직근의 최대 등척성 수축력 변화)

  • Lim, Sang-Wan;Lee, Jeong-Woo;Kim, Tae-Youl;Song, Myung-Soo;Choi, Eun-Young
    • Journal of the Korean Academy of Clinical Electrophysiology
    • /
    • v.2 no.3
    • /
    • pp.25-35
    • /
    • 2004
  • The purpose of this study was compared to MTICs(maximal tolerated isometric contraction), decrement and recovery. For this, using isokinetic exercise analysis device(Biodex Medical Systems Inc., Biodex System 3PRO, USA), low rate(20 Hz) and high rate(100 Hz) NMES(neuromuscular electrical stimulation) were applied to the quadriceps muscles of fifteen patients with spastic hemiplegia caused by lesions in the central nervous system. The results were as follows: 1. It was shown to fast decrement in the middle of phase at low rate NMES and to slow decrement of MTIC response at high rate NMES(p<.01). 2. It was shown to fast recovery at high rate NMES and to slow recovery at low rate NMES in recovery tendency of MTIC(p<.01). These conclusions suggest that NMES of high rate caused to slow fatigue and fast recovery different from low rate NMES.

  • PDF

Pharmacological Studies of Plantaginis Semen (차전자(車前子)(질경이)의 약리학적(藥理學的) 연구(硏究))

  • Ko, Suk-Tai;Lim, Dong-Yoon
    • Journal of Pharmaceutical Investigation
    • /
    • v.7 no.1_4
    • /
    • pp.28-37
    • /
    • 1977
  • The pharmacological actions to methanol extract(PME) obtained from Plantaginis semen were examined in the rabbit. 1) PME, when administered into the vein of rabbit, produced the fall of blood pressure and stimulation of respiration. The former action was inhibited by atropine but the latter not affected by atropine. 2) PME caused contraction in both isolated intestinal and uterus strips, atropine blocked the contraction of intestinal strips while did not the uterus contraction. 3) PME decreased the heart rate of rabbit anesthetized with urethane. 4) PME elicited antidiuresis with doses ranging from 10mg/kg. The antidiuresis appeared to be related to the hemodynamic changes decreases in the renal plasma flow and glomerular filtration rate. Urinary sodium and potassium decrease in the renal plasma flow and glomerular filtration rate. Urinary sodium and potassium decrease in relation to the diminished filtration.

  • PDF

An ergonomic Study on the function of Slacks -On the Expansion and Contraction of the Skin Surface of the Lower Body- (Slacks의 기능성에 관한 인간공학적 연구 -동하부 및 대퇴부의 신축을 중심으로-)

  • 함옥상
    • Journal of the Korean Home Economics Association
    • /
    • v.19 no.2
    • /
    • pp.151-163
    • /
    • 1981
  • This study was to investigate the changes of shape of the surface square measurements, the rate, measurements of expansion and contraction and correlation. In this study was found the following: 1. According to the developmental illustration of the shell it was revealed that there was a great change in the thigh area of the body. When the leg was raised and the waist bent forward the front sections of the abdomen were contracted and the center back of the hip was expanded. 2. It was found that the contraction was present in the girth of the back section and front section was expanded in the rate of the body surface. In the length from the middle waist to hip the front area showed a great deal of contraction the back area of the hip & thigh revealed a great deal of expansion. 3. By the somatometry, the measurements of the expansion and contraction of the body surface, there was a great change in waist and hip. It revealed that the maximum expansions of waist and hip line in the chair were 1.8cm and 4.08cm respectively. Therefor, when slacks are made at least the amount of ease of 1.8cm of waist line and 4cm of hip line must be made and the allowance of the center back of hip area must be made. 4. It revealed that there was a correlation between waist and hip girth.

  • PDF

An Ergonomic Study on the Function of the Basic Pattern of Clothing -On the Expansion and Contraction of the Skin Surface of the Upper Body- (의복 원형의 기능성에 관한 인간공학적 연구)

  • 함옥상
    • Journal of the Korean Home Economics Association
    • /
    • v.17 no.4
    • /
    • pp.1-14
    • /
    • 1979
  • The functional problems of the basic pattern of clothing are a matter of the first importance to clothing construction. Therefore, the ergonomic analysis of the expansion and contraction of the upper body surface, due to motion, has become required. thus in order to obtain the measurements and rate of expansion and contraction of the upper body surface following from its motions, the development figure of " Shell" and somatometry were employed. The results obtained through the investigation can be summarized as follows : 1) According to the developmental figures of "Shell" the latitudes centering around the shoulder line present contractive tendencies by arm movement. The longitudes around the center back waist length are expansive tendencies when bent forward. In the case of a 15$^{\circ}$ lean backward posture, the longitudes around the center front waist length are expansive tendencies. 2) By somatometry, the region from the scapula to the axilla point the upper back with presents the greatest expansion (more than 30%). The region from scapla to arm presents the maximum rate of contraction. In considering the longitude , under the axilla waist length and the bust point waist length generally shows the greatest rate of expansion. 3) The bust point waist length and under the axilla waist length are of great importance to the basic pattern of clothing. and have expansive tendencies(6.3cm). Among the latitudes, the upper back width has the greatest tendency for expansion (7.83 cm). 4) The region which presents the greatest rate of the expansion and contraction is in the proximity of the arm. These results testify that the amount of room of the back width must be given consideration in constructing the basic pattern of clothing.pattern of clothing.

  • PDF

Blood Pressure and Heart Rate Responses to Concentric, Eccentric, Isometric Exercises (구심성, 원심성, 등척성 운동방법에 따른 혈압과 심박수의 변화)

  • Jung, Yeon-Tai;Kim, Ki-Hun;Current, Marion E.;Han, So-Young
    • Physical Therapy Korea
    • /
    • v.1 no.1
    • /
    • pp.75-82
    • /
    • 1994
  • The purpose of this study is to determine cardiovascular reponses to concentric, eccentric and isometric exercise applied to the knee extensor muscle group. Exercise types studied were concentric, eccentric and isometric. The subjects were sixty healthy male volunteers who had no hypertension or cardiac disease. Heart rate, systolic and diastolic blood pressure were recorded prior to starting exercise. The subjects also performed 10RM on right lower extremity. A N-K table was used for three exercises to right knee extensors. Each exercise was selected randomly and applied to each subject 10 times in a 10 second. After each exercise, heart rate, systolic and diastolic blood pressure were recorded immediately. Findings were as follows concectric contractions had a greater effect on the increase of systolic blood pressure and heart rate than eccentric or isometric contractions. Diastolic blood pressure is influenced only by isometric contractions. Eccentric contractions have less effect on the increase of systolic blood pressure and heart rate than concentric or isometric contractions. We hope that the results of this experiment can be adapted to exercise programs for patients with cardiac disease.

  • PDF

Effects of Transcutaneous Electrical Nerve Stimulation(TENS), Self-Stretching and Functional Massage on the Muscle Fatigue by Maximum Muscular Strength

  • Yoon, Jung Gyu;Ryu, Je Ju;Roh, Hye Won;Yang, Hyun Ah;Lee, Sang Bin
    • Journal of International Academy of Physical Therapy Research
    • /
    • v.3 no.2
    • /
    • pp.422-428
    • /
    • 2012
  • The present study purposed to examine the effects of transcutaneous electrical nerve stimulation, self-stretching and functional massage on the recovery of muscle contraction force for muscle fatigue caused by sustained isotonic contraction. The subjects of this study were 45 healthy students. They were divided into transcutaneous electrical nerve stimulation group(n=15), self-stretching group(n=15) and functional massage group(n=15), and using Primus RS. We observed the pattern of changes in maximal voluntary isometric contraction force(MVIC) after causing muscle fatigue in quadriceps femoris muscle through sustained isotonic contraction. Maximal voluntary isometric contraction force(MVIC) were greatly increased after transcutaneous electrical nerve stimulation, self-stretching and functional massage. In the comparison of recovery rate of muscle contraction force for muscle fatigue caused by sustained isotonic contraction among the treatment groups, it did not show any significant differences. However, it showed that each treatment may be effective in recovery of muscle fatigue caused by sustained isotonic contraction.

Personalized Specific Premature Contraction Arrhythmia Classification Method Based on QRS Features in Smart Healthcare Environments

  • Cho, Ik-Sung
    • Journal of IKEEE
    • /
    • v.25 no.1
    • /
    • pp.212-217
    • /
    • 2021
  • Premature contraction arrhythmia is the most common disease among arrhythmia and it may cause serious situations such as ventricular fibrillation and ventricular tachycardia. Most of arrhythmia clasification methods have been developed with the primary objective of the high detection performance without taking into account the computational complexity. Also, personalized difference of ECG signal exist, performance degradation occurs because of carrying out diagnosis by general classification rule. Therefore it is necessary to design efficient method that classifies arrhythmia by analyzing the persons's physical condition and decreases computational cost by accurately detecting minimal feature point based on only QRS features. We propose method for personalized specific classification of premature contraction arrhythmia based on QRS features in smart healthcare environments. For this purpose, we detected R wave through the preprocessing method and SOM and selected abnormal signal sets.. Also, we developed algorithm to classify premature contraction arrhythmia using QRS pattern, RR interval, threshold for amplitude of R wave. The performance of R wave detection, Premature ventricular contraction classification is evaluated by using of MIT-BIH arrhythmia database that included over 30 PVC(Premature Ventricular Contraction) and PAC(Premature Atrial Contraction). The achieved scores indicate the average of 98.24% in R wave detection and the rate of 97.31% in Premature ventricular contraction classification.

Influence of Aging on Surface EMG Signals Generated Under Sustained Fixed Load Contraction (고정 부하 수축시 기록한 표면근전도 신호에 대한 노화의 영향)

  • Lee, Jin;Kim, Sung-Hwan
    • The Transactions of The Korean Institute of Electrical Engineers
    • /
    • v.59 no.8
    • /
    • pp.1497-1505
    • /
    • 2010
  • The present study was performed to investigate the effect of aging on muscular activity of older subjects under the condition of fixed load muscle contraction. SEMG signals were recorded from old (46 women) and young (45 women) groups performing sustained isometric elbow flexion contraction with a fixed load during 30 seconds. Linear regression and mean square error (MSE) analysis with four characteristic variables (ARV, RMS, MDF, MNF) were used to compare the age-related difference (of local muscle fatigue and fluctuation of the amplitude and frequency) in the SEMG signal. The main results can be summarized as follows: During sustained muscle contraction with a fixed load: i) the MSE values of amplitude (ARV, RMS) and frequency (MDF, MNF) variables were more than 30% higher for the young than for the old adults; ii) the measures of local muscle fatigue (slope of the MDF and MNF) indicated greater fatigue in the old; and iii) the rate of increase of the SEMG amplitude was higher for the young than the old.

PERFORMANCE BY WIDTH CONTRACTION IN VANELESS DIFFUSER OF CENTRIFUGAL COMPRESSOR BY COMPUTATIONAL FLUID DYNAMICS (전산해석을 통한 원심압축기용 디퓨저의 폭변화에 따른 성능 연구)

  • Lee, S.C.;Lee, W.S.;Shin, Y.H.;Chung, J.T.
    • 한국전산유체공학회:학술대회논문집
    • /
    • 2010.05a
    • /
    • pp.136-141
    • /
    • 2010
  • This study describes effects of width contraction in vaneless diffuser on the performance of centrifugal compressors using commercial CFD code. Numerical analysis for three different diffusers such as Parallel, half contraction, and full contraction was performed. The results show that the performance of the centrifugal compressor is improved through the use of the diffusers with width parallel in high flow rate. The width contraction of diffusers is influenced static pressure rises. Comparison with the experimental data shows agreement.

  • PDF