• Title/Summary/Keyword: Height effect

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Strengthening of axially loaded concrete columns using stainless steel wire mesh (SSWM)-numerical investigations

  • Kumar, Varinder;Patel, P.V.
    • Structural Engineering and Mechanics
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    • v.60 no.6
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    • pp.979-999
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    • 2016
  • Stainless steel wire mesh (SSWM) is an alternative material for strengthening of structural elements similar to fiber reinforced polymer (FRP). Finite element (FE) method based Numerical investigation for evaluation of axial strength of SSWM strengthened plain cement concrete (PCC) and reinforced cement concrete (RCC) columns is presented in this paper. PCC columns of 200 mm diameter with height 400 mm, 800 mm and 1200 mm and RCC columns of diameter 200 mm with height of 1200 mm with different number of SSWM wraps are considered for study. The effect of concrete grade, height of column and number of wraps on axial strength is studied using finite element based software ABAQUS. The results of numerical simulation are compared with experimental study and design guidelines specified by ACI 440.2R-08 and CNR-DT 200/2004. As per numerical analysis, an increase in axial capacity of 15.69% to 153.95% and 52.39% to 109.06% is observed for PCC and RCC columns respectively with different number of SSWM wraps.

Effect of High-heel Shoes on Muscle Activity of the Lower Limbs (신발 굽의 높이가 하지근육 근활성도에 미치는 영향)

  • Ma, Sang-Yeol;An, Seong-Ja
    • PNF and Movement
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    • v.10 no.1
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    • pp.35-41
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    • 2012
  • Purpose : This study was conducted to identify the effects of high heel shoes on surface electromyography(EMG) activities fo tibialis anterior(TA), soles(S), and gastrocnemius(G) in 12 healthy women. Methods : Subjects were composed of three group(sports shoes, 5cm heel height shoes, and 9cm heel height shoes). The muscle activity of the TA, G, S in the lower leg were measured using a surface EMG. Results : Results of one way repeated measures ANOVA of the after waling 30minutes standing task duration among the sport shoes, 5cm, and 9cm heel height conditions. The comparison of the muscular activities showed significant differences in the G muscles among the high heel shoes. Conclusion : Wearing high heel shoes for hours will bring inappropriate alignment of the lower limbs and cause postural changes or abnormal sensation and several other problems in the body, resulting in exposure to ankle sprain or fall injuries.

On wave propagation of football ball in the free kick and the factors affecting it

  • Xumao Cheng;Ying Wu
    • Steel and Composite Structures
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    • v.46 no.5
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    • pp.669-672
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    • 2023
  • In this research, the researcher has examined the factors affecting the movement of the soccer ball and will show that the effects such as air resistance, altitude above sea level, wind, air pressure, air temperature, air humidity, rotation of the earth, changes in the earth's gravitational acceleration in different areas. It, the geographical length and latitude of the launch point, the change of gravitational acceleration with height, the change of pressure with height, the change of temperature with height and also the initial spin (Magnus effect) affect the movement of projectiles (especially soccer ball). We modelled th ball based on shell element and derive the motion equations by energy method. Finally, using numerical solution, the wave of the ball is studied. The influences of various parameters are investigated on wave propagation of the ball. Therefore, in short, it can be said that the main factors that play a major role in the lateral deviation of the hit ball are the initial spin of the ball and the wind.

The Effect of Ion Implantation on the Barrier Height in PtSi-nSi Schottky Diode (PtSi-nSi 쇼트키 다이오드에서 이온 주입이 장벽높이의 변화에 미치는 영향)

  • Lee, Yong Jae;Lee, Moon Key;Kim, Bong Ryul
    • Journal of the Korean Institute of Telematics and Electronics
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    • v.23 no.5
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    • pp.712-718
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    • 1986
  • A shallow n+ layer of implanted phosphorus was used to lower the barrier height of PtSinSi schottky diodes. The reduction of barrier height of the forward turn-on voltages from 400mV to 180mV of the forward was followed by implantation of phosphorus at 35KeV with an ion dose of 8.0x10**12 atoms/cm\ulcornerand was activated at 925\ulcorner for 30min in dry O2. The test result showed that, as the ion-implanted dose increased, the forward turn-on voltage and reverse breakdown voltage were linearly decreased, but the saturation current and ideality factor(n) were linearly increased.

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Effect of Extension of Grazing Duration in Late Autumn on Grass Growth in Following Spring (만추 방목기간의 연장이 이듬해 봄 목초의 생육에 미치는 영향)

  • ;;Masahiko Okubo
    • Journal of The Korean Society of Grassland and Forage Science
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    • v.20 no.3
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    • pp.161-168
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    • 2000
  • The experiment was carried out to investigate the effect of extension of grazing duration in late autumn on grass growth in following spring, in order to improve the rate of self-sufficiency for roughage feed. Plant height, total biomass and litter production of herbage were increased when the grazing was finished early in late autumn. The proportions of clover and litter, and amounts of animal intake were decreased, with extended grazing duration in late autumn. But when the grazing was finished late in autumn, the contents of crude protein (CP, %) of herbage were increased, contents of acid detergent fiber (ADF, %), neutral detergent fiber (NDF, %) and crude ash (%) were decreased in pasture after grazing, therefore the contents of total digestible nutrients (TDN, %) and relative feed value (RFV) of herbage were improved. The early end grazing showed that plant height, total biomass and litter production of herbage in following spring were higher than those in late end grazing. However, increased yields were not significantly different among end grazing treatments (0.12-0.15 tonha), except for the final end grazing in late autumn (0.01 tonha). With extended grazing duration in late autumn, the contents of CP of herbage in following spring were increased, contents of ADF, were decreased, and RFV were improved. (Key words : Extension of grazing duration, Plant height, Biomass, Amount of intake, Increased yield, Crude protein, TDN) rll\ulcorner c# qiil x i 9 ~ 1 a% * (College of Natural Resources, Taegu Univ., Kyongsan, 71 2-714, Korea) * $4 4 qiil 34 qq(Co1lege of Liberal Arts & Sciences, Yonsei Univ., Wonju, 220-701, Korea) '* 8 * jL@%ft@ &@%(Faculty of Agriculture, Hokkaido Univ., Sapporo, 060 Japan)

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The effect of Arch Support Taping on Plantar Pressure and Navicular Drop Height in subjects with Excessive pronated foot during 6 Weeks (6주간의 활지지 테이핑(arch support taping) 적용이 과도하게 엎침된 발의 발바닥압력과 발배뼈 높이에 미치는 영향)

  • Kim, Tae-Ho;Koh, Eun-Kyung;Jung, Do-Young
    • Journal of the Korean Society of Physical Medicine
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    • v.6 no.4
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    • pp.489-496
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    • 2011
  • Purpose : The purpose of this study was to identify the effect of an arch support taping on navicular drop height and plantar pressure in the subjects with excessive pronated foot for 6 weeks. Methods : The fifteen subjects with the pronated foot group and the fifteen subjects with the normal foot group volunteered for this study. Both groups were applied arch support taping at 3 times a week during 6 weeks. Subjects were assessed navicular drop test to evaluate pronation of subtalar joint and plantar pressure on treadmill for pressure measuring system during walking with a bare foot state at pre- taping, after 3 weeks, and after 6 weeks. A two-way repeated analysis of variance design was used to examine the difference of navicular drop height and plantar pressure in the pronation foot group and the normal foot group. Results : The pronated foot group had significantly decreased both the navicular drop height and the plantar pressure under the medial midfoot than the normal foot group after 6 weeks(p<.01). Conclusions : This study proposed that an arch support taping can be support to lift navicular bone as well as to transfer the foot pressure from medial midfoot to lateral midfoot in individuals with excessive pronated foot.

Experiment on the Limit Scale of Combustion in Constant Volume Micro Combustor (초소형 정적 연소기에서의 연소 한계에 대한 실험적 연구)

  • 나한비;권세진;김세훈;이대훈
    • Journal of the Korean Society of Propulsion Engineers
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    • v.7 no.4
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    • pp.27-32
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    • 2003
  • The Performance of micro combustor in various condition was exploited experimentally. Various geometric conditions of combustor were considered to figure out the performance of micro combustor. The micro combustor studied in this study was constant volume with cylindrical shape. Geometric parameters of combustor were defined to be combustor height and diameter. The effect of height was exploited parametrically with the size of 1mm, 2mm and 3mm. The effect of diameter was observed parameterized with 7.5mm and 15mm. Three different combustibles or Stoichiometric mixture of methane/air, hydrogen/air were used. Pressure transition during combustion process was recorded. The maximum pressure by combustion responded favorably with the change of height of combustor and the initial pressure. The flame propagation was visulized using Schlieren method. The flame propagation within combustor was observed when specific conditions such as combustor height and initial pressure over critical value was satisfied.

A numerical study of a confined turbulent wall jet with an external stream

  • Yan, Zhitao;Zhong, Yongli;Cheng, Xu;McIntyre, Rory P.;Savory, Eric
    • Wind and Structures
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    • v.27 no.2
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    • pp.101-109
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    • 2018
  • Wall jet flow exists widely in engineering applications, including the simulation of thunderstorm downburst outflows, and has been investigated extensively by both experimental and numerical methods. Most previous studies focused on the scaling laws and self-similarity, while the effect of lip thickness and external stream height on mean velocity has not been examined in detail. The present work is a numerical study, using steady Reynolds-Averaged Navier Stokes (RANS) simulations at a Reynolds number of $3.5{\times}10^4$, of a turbulent plane wall jet with an external stream to investigate the influence of the wall jet domain on downstream development of the flow. The comparisons of flow characteristics simulated by the Reynolds stress turbulence model closure (Stress-omega, SWRSM) and experimental results indicate that this model may be considered reasonable for simulating the wall jet. The confined wall jet is further analyzed in a parametric study, with the results compared to the experimental data. The results indicate that the height and the width of the wind tunnel and the lip thickness of the jet nozzle have a great effect on the wall jet development. The top plate of the tunnel does not confine the development of the wall jet within 200b of the nozzle when the height of the tunnel is more than 40b (b is the height of jet nozzle). The features of the centerline flow in the mid plane of the 3D numerical model are close to those of the 2D simulated plane wall jet when the width of the tunnel is more than 20b.

The Effect of Stage Ceiling Height on the Acoustic Characteristics of Concert Halls (콘서트홀의 무대 천장높이 변화에 의한 객석음향의 영향)

  • Shin Dong-Jae;Jeon Jin-Yong;Seo Hyung-Gyoon
    • The Journal of the Acoustical Society of Korea
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    • v.24 no.1
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    • pp.21-28
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    • 2005
  • In this Paper, the effect of stage ceiling height on the acoustic characteristics of rectangular concert halls are investigated. To find out the acoustic properties of audience area, A simple Boston Symphony Hall(BSH) model which is typically rectangular shaped was applied for computer simulation. A newly built rectangular concert hall with 400 seats was also chosen for a scale model $(1.2m{\times}0.68m{\times}0.31m)$ study and its computer simulation varing the stage ceiling height and the volume. The results show that RT increased as the stage ceiling was lowered and the difference rate of RT by its variance is from -0.09 to -0.06[sec/m].

Effects of Modified Low-Dye Taping on Stroke Patients with an Excessive Pronated Foot (과도하게 엎침된 발을 가진 뇌졸중 환자에게 적용된 수정 발바닥활 지지 테이핑의 효과)

  • Kim, Hyun-Wook;Ryu, Young-Uk
    • Journal of the Korean Society of Physical Medicine
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    • v.13 no.2
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    • pp.69-74
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    • 2018
  • PURPOSE: Stroke patients may develop an over-pronated foot, resulting in a lower medial longitudinal arch. This can lead to a structural change of the foot due to deformation of the musculoskeletal system. The purpose of this study was to examine the effects of modified low-dye taping on stroke patients with an excessively pronated foot. The effect of the taping on the foot after light daily activity was also examined. METHODS: The subjects consisted of 21 stroke patients with an excessively pronated foot, as measured by the navicular drop test. First, their navicular heights were measured at a relaxed standing position (measure 1) and while standing in the subtalar neutral position (measure 2). Modified low-dye taping was applied to each subject's affected foot and the navicular height was then measured for the standing posture (measure 3). Finally, each subject walked around for 10 minutes and the navicular height was measured again (measure 4). RESULTS: Statistical analyses showed that the navicular height value at the relaxed standing position (measure 1) was significantly lower than for the other 3 measurements. That is, the modified low-dye taping was effective in maintaining a subtalar neutral position, even after a 10-minute walk, for stroke patients with an excessively pronated foot. CONCLUSION: The results suggest that modified low-dye taping applied to stroke patients with an excessively pronated foot could be an effective way to place the subtalar joint in a neutral position, and that its effect can be sustained for light daily activities.