• Title/Summary/Keyword: Compression Effect

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The Effect of Compression Wear for the Sport Performance and Muscle Function (컴프레션웨어(Compression Wear)의 운동성능 및 근기능에 미치는 영향)

  • Koo, Young-Seok
    • Textile Coloration and Finishing
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    • v.23 no.1
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    • pp.60-68
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    • 2011
  • The effect of compression wear for sport performance and muscle function was investigated based on the physiological test and electromyograph(EMG). The EMG test was used to study muscle activity after fitting the compression wear during exercise. It showed slight difference between men and women testee groups in the results of anaerobic, aerobic, fatigue, and EMG test due to muscle content in the body. In addition, the exercise performance was increased to some extent even the muscle activity was decreased. It is estimated that the compression effect to muscle by the compression wear decreased the muscle vibration and improved blood circulation which helped the entire sport performance. However, it is necessary to study the effect of compression wear in long-term wearing in the future study.

Effect of Vibration during Distribution Process on Compression Strength of Corrugated Fiberboard Containers for Agricultural Products (농산물 골판지포장상자의 수송 중 진동에 의한 압축강도 변화)

  • Jo, Jung-Youn;Shin, Jun-Sub;Kim, Jong-Kyoung
    • Proceedings of the Korea Technical Association of the Pulp and Paper Industry Conference
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    • 2008.04a
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    • pp.290-307
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    • 2008
  • The aim of this study was to estimate adverse effect on compression strength of corrugated fiberboard containers due to vibration during distribution process. Distribution environment such as road conditions and compression strength of corrugated fiberboard containers for selected agricultural products were studied. We found that increasing humidity does not effect significantly on natural frequencies of boxes, but results in accelerative effect to decrease compression strength of boxes. Box structures and product types also effect on loss of compression strength greatly.

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Effect of Compression Ratio on the Combustion Characteristics of a Thermodynamics-Based Homogeneous Charge Compression Ignition Engine

  • Han, Sung Bin
    • Journal of Energy Engineering
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    • v.24 no.3
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    • pp.61-66
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    • 2015
  • Homogeneous charge compression ignition (HCCI) engine combines the combustion characteristics of a compression ignition engine and a spark ignition engine. HCCI engines take advantage of the high compression ratio and heat release rate and thus exhibit high efficiency found in compression ignition engines. In modern research, simulation has be come a powerful tool as it saves time and also economical when compared to experimental study. Engine simulation has been developed to predict the performance of a homogeneous charge compression ignition engine. The effects of compression ratio, cylinder pressure, rate of pressure rise, flame temperature, rate of heat release, and mass fraction burned were simulated. The simulation and analysis show several meaningful results. The objective of the present study is to develop a combustion characteristics model for a homogeneous charge compression ignition engine running with isooctane as a fuel and effect of compression ratio.

Effect of Degree of Compression on Texture Profile Parameters of Starch gels (압착율에 따른 전분 gel의 Texture Profile Parameter의 변화)

  • 윤계순
    • Journal of the Korean Home Economics Association
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    • v.26 no.3
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    • pp.103-108
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    • 1988
  • Texture Profile Analysis (TPA) on cowpea and mung bean starch gels was performed with the Instron and the effect of the degree of compression on TPA parameters measured. Fracturability was almost independent of the degree of compression. hardness usually increased with increasing compression. Cohesiveness and chewiness decreased for mung bean starch gel as compression increases. Springiness in two starch gels increased a little from 55% to 65% compression and then decreased from 75% to 95% compression. Gumminess for mung bean starch gels decreased steeply from 55% to 75% compression, then it increased moderately up to 95% compression. Since the TPA parameters vary so widely with degree of compression, all TPA measurements should standardize the degree of compression.

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Second order effects of external prestress on frequencies of simply supported beam by energy method

  • Fang, De-Ping
    • Structural Engineering and Mechanics
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    • v.52 no.4
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    • pp.687-699
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    • 2014
  • Based on the energy method considering the second order effects, the natural frequencies of externally prestressed simply supported beam and the compression softening effect of external prestress force were analyzed. It is concluded that the compression softening effect depends on the loss of external tendon eccentricity. As the number of deviators increases from zero to a large number, the compression softening effect of external prestress force decreases from the effect of axial compression to almost zero, which is consistent with the conclusion mathematically rigorously proven. The frequencies calculated by the energy method conform well to the frequencies by FEM which can simulate the frictionless slide between the external tendon and deviator, the accuracy of the energy method is validated. The calculation results show that the compression softening effect of external prestress force is negligible for the beam with 2 or more deviators due to slight loss of external tendon eccentricity. As the eccentricity and area of tendon increase, the first natural frequency of the simply supported beams noticeably increases, however the effect of the external tendon on other frequencies is negligible.

Fixation of Compression Set of Heat-Compressed Wood by Steaming (수증기 처리에 의한 열압밀화목재의 압축 고정)

  • 이원희;한규성
    • Journal of the Korea Furniture Society
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    • v.11 no.1
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    • pp.85-89
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    • 2000
  • This study investigated the effect of steaming on fixation of compression set and the effect of these treatments on mechanical properties of heat-compressed wood specimens. To determine the effect of steaming after compression set, wood specimens were compressed for 100min at 180f and then steamed for 20-100min at $120^{\circ}C$. Swelling tests were used to evaluate recovery of compression set. Bending, compression, and Brinell hardness tests were carried out for evaluating mechanical properties. Compressed wood steamed for 100 min at $120^{\circ}C$ showed 1.9% recovery of set, increases in bending and compressive properties, and no hardness change. We concluded that almost complete fixation of compression set in wood can be achieved by steaming compressed wood.

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Study of Shock Tube for Wave Phenomenon in High Speed Railway Tunnel(II)-attenuation and Nonlinear Effect of Compression Waves- (고속철도 터널에서 발생하는 파동현상에 관한 충격파관의 연구(2)-압축파의 감쇠와 비선형효과-)

  • ;;Matsuo, Kazuyasu
    • Transactions of the Korean Society of Mechanical Engineers
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    • v.19 no.8
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    • pp.1972-1981
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    • 1995
  • As a railway train enters a tunnel at high speed, a compression wave is formed in front of the train and propagates along the tunnel. The compression wave subsequently emerges from the exit of the tunnel, which causes an impulsive noise. The impulsive noise is closely related to the pressure gradient of the compression wave propagating the tunnel. In order to investigate the characteristics of the compression waves, in the present study an experiment was made using a shock tube. The results show that the strength of a compression wave decreases with the distance from the tunnel entrance and the nonlinear effect of compression wave appears to be significant if strength of the initial compression wave is greater than 7 kPa. Furthermore if the wave pattern is known, attenuation of the compression wave propagating in a tunnel can be reasonably predicted by a theoretical equation considering viscous action and heat transfer in boundary layer.

Vowel Compression due to Syllable Number in English and Korean

  • Yun, Il-Sung
    • Speech Sciences
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    • v.9 no.4
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    • pp.165-173
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    • 2002
  • Strong compression effects in a stressed vowel due to the addition of syllables have been adopted as evidence for stress-timing. In relation to this, Yun (2002) investigated the compression effects of number of syllables on Korean vowel. The results generally revealed that Korean had neither significant nor consistent anticipatory or backwards compression effects, especially when it came to the sentence level. This led us to claim that Korean would not be a stress-timed language. But the language investigated in the study was only Korean, and further cross-linguistic research was needed to confirm the claim. In this study, Yun's (2002) sentence level data are compared with Fowler's (1981) English data. The comparison reveals that Korean seems to be similar to English in the backwards compression effect, whereas the two languages are markedly different in the anticipatory compression effect. Thus, if English is a stress-timed language and the strong anticipatory compression effect is evidence in favour of stress-timing as is claimed, the present cross-linguistic study confirms Yun's (2002) suggestion-Korean is unlikely to be stress-timed. On the other hand, compression effects are revisited: the differences in vowel compression between English and Korean are discussed from the syntactic and phonological points of view.

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A Study on the Equi-biaxial Tension Test of Rubber Material (고무재료의 등 이축 인장시험에 관한 연구)

  • 김완두;김동진;김완수;이영신
    • Transactions of the Korean Society of Automotive Engineers
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    • v.11 no.5
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    • pp.95-104
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    • 2003
  • The material properties of rubber was determined by the experiments of uniaxial tension, uniaxial compression, planer tension, equi-biaxial tension and volumetric compression. In compression test, it is difficult to obtain the pure state of compression stress and strain due to friction force between the specimen and compression platen. In this study, the stress and strain data from the equi-biaxial tension test were converted to compression stress and strain and compared to a pure state of simple compression data when friction was zero. The compression test device with the tapered platen was proposed to overcome the effect of friction. It was fumed out that the relationship of the stress and strain using the tapered platen was in close agreement with the pure compressive state.

Pullout Behavior of Typical friction Anchors and Development of Design Method (앵커 형식별 인발거동과 설계법 개발)

  • 송일준;김가야;홍석우
    • Journal of Ocean Engineering and Technology
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    • v.17 no.4
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    • pp.43-51
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    • 2003
  • The resistance mechanism of anchor changes according to the types of anchor. Friction anchors are classified into tension and compression types. In this study, the characteristics and mechanism of pullout are analysed, and the design method of anchor and computer program for design are developed through compression test results of anchor body grout. The characteristics of compression anchor, compared with tension anchor, are summarized mainly as follows: (1) The effect of progressive failure of compression anchor body are much smaller than those of tension anchor during pullout of anchor: (2) The skin friction resistance is increased by Possion effect of grout (anchor body) during pullout of compression anchor.