• Title/Summary/Keyword: Back Stress

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Long-term Behavior Characteristics of Backfilled Ground by EPS (EPS로 뒷채움된 지반의 장기거동특성)

  • Chun, Byung-Sik;Jung, Chang-Hee;Choi, Hui-Rim
    • Journal of the Korean Geotechnical Society
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    • v.23 no.10
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    • pp.151-161
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    • 2007
  • EPS provides a superb self-sufficient stability. Studies on the process of EPS construction method focus on the inchoate phase of general construction, which is increasingly applied to construction sites throughout the world. Unfortunately, there has been little study on the durability and long-term soil behavior involving EPS materials. In this study, the boring, in-site and laboratory tests were conducted to examine the long-term soil behavior in the back-filling of alternating behind the side to which EPS was applied. And results of finite element analysis considering various test results and the soil behavior data measured during the construction show that EPS construction method is a superb process that relieves the load and consequently reduces the settlement, alleviates the stress on the abutment, and prevents lateral flow.

Effects of High-Frequency Treatment using Radiofrequency on Autonomic Nervous System and Pain in Women with Dysmenorrhea

  • Sungeon Park;Seungwon Lee;Inok Kim
    • Physical Therapy Rehabilitation Science
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    • v.11 no.4
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    • pp.493-501
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    • 2022
  • Objective: The purpose of this study is to present basic data for appropriate therapeutic intervention by confirming changes in the autonomic nervous system and pain by applying high-frequency deep diathermy to the lower abdomen in patients with primary dysmenorrhea. Design: A randomized controlled clinical trial. Methods: Thirty-eight women aged 18-50 years who complained of regular menstrual cycles (24-32 days) and primary dysmenorrhea symptoms were randomly assigned to a high-frequency therapy group (5, 7, or 9 mins) and a superficial heat therapy group (20 min). High frequency treatment group: The subject was in a supine position, and radio frequency was applied to the lower abdomen below the umbilicus. The radio frequency therapy device used in this study uses a 300 kHz capacitive electrode and a 500 kHz resistive electric transfer to deliver deep heat. Superficial heat treatment Group: Subjects applied a hot pack to the lower abdomen for 20 minutes while lying on their back. Evaluations were made of Heart rate variability and Visual Analogue Scale. Results: In subjects with menstrual pain, there was a significant difference in pain between the high-frequency therapy group and the superficial heat therapy group (p=0.026). However, there was no significant difference between the autonomic nervous system and the stress resistance (p>0.05). Conclusions: As a result of this study, high-frequencytreatment using radiofrequency was effective in relieving pain because it can penetrate deeper tissues than conventional hot packs using superficial heat. In particular, it was found that the optimum effect was obtained when high frequency was applied forfive-seven minutes.

Seismic performance of lightweight aggregate concrete columns subjected to different axial loads

  • Yeon-Back Jung;Ju-Hyun Mun;Keun-Hyeok Yang;Chae-Rim Im
    • Structural Engineering and Mechanics
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    • v.88 no.2
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    • pp.169-178
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    • 2023
  • Lightweight aggregate concrete (LWAC) has various advantages, but it has limitations in ensuring sufficient ductility as structural members such as reinforced concrete (RC) columns due to its low confinement effect of core concrete. In particular, the confinement effect significantly decreases as the axial load increases, but studies on evaluating the ductility of RC columns at high axial loads are very limited. Therefore, this study examined the effects of concrete unit weight on the seismic performance of RC columns subjected to constant axial loads applied with different values for each specimen. The column specimens were classified into all-lightweight aggregate concrete (ALWAC), sand-lightweight aggregate concrete (SLWAC), and normal-weight concrete (NWC). The amount of transverse reinforcement was specified for all the columns to satisfy twice the minimum amount specified in the ACI 318-19 provision. Test results showed that the normalized moment capacity of the columns decreased slightly with the concrete unit weight, whereas the moment capacity of LWAC columns could be conservatively estimated based on the procedure stipulated in ACI 318-19 using an equivalent rectangular stress block. Additionally, by applying the section lamina method, the axial load level corresponding to the balanced failure decreased with the concrete unit weight. The ductility of the columns also decreased with the concrete unit weight, indicating a higher level of decline under a higher axial load level. Thus, the LWAC columns required more transverse reinforcement than their counterpart NWC columns to achieve the same ductility level. Ultimately, in order to achieve high ductility in LWAC columns subjected to an axial load of 0.5, it is recommended to design the transverse reinforcement with twice the minimum amount specified in the ACI 318-19 provision.

A Survey on Risk Factors Related to Experience Rate of Low Back Pain in High School Students (일부지역 고등학생들의 요통경험율과 관련 요인 -안동시를 중심으로-)

  • Kim, Shun-Yeop;Yi, Seung-Ju;Park, Sang-Rae;Jang, Young-Ho;Cha, Sang-Eun;Kim, Ji-Sook
    • Journal of Korean Physical Therapy Science
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    • v.2 no.3
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    • pp.653-666
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    • 1995
  • This study was conducted to investigate factors related to experience rate of low back pain(LBP) in the high school students, a questionnaire survey was carried out for 778 high school students in Andong city Kyungsang Pook province from 28th June to 10th July, 1993. The results were as follows: The experience rate of LBP for 778 high school students who were interviewed was 27.1 %. Unknown(47.4 %) was the highest in the cause of LBP. The experience rate of a academical high school students (57.8 %) was higher than the technical high school students(42.7 %) in association according to LBP and school division(P = 0. 001). The experience rate of 18 years old above students (60.2 %) was higher than 17 years old below school students(39.8 %%) in association between LBP and age(P = 0.031). The experience rate of students who go to bed at the hot floored bed (80.1 %) was higher than students who go to bed at the bed room (11.8 %) in association between LBP and room type(P = 0.012). The statisticaly significant variables related to LBP were school division, age and stress. It was revealed by this survey that independent variables related to LBP experience rate of high school students were important health problem. So the prospective research is need by those variables.

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Effect of JiaoTeng-Yuan(交藤圓) on Oxidation Stress Caused by D-galactose in Sprague-Dawley Rats (교등원(交藤圓)이 백서(白鼠)의 산화유발(酸化誘發)을 방어(防禦)하는 작용(作用)에 관(關)한 연구(硏究))

  • Lee Song-Shil;Lee Sang-Jae;Kim Kwang-Ho
    • Journal of Society of Preventive Korean Medicine
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    • v.8 no.2
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    • pp.141-156
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    • 2004
  • Objectives : JianTeng-Yuan(交藤圓) is said to be a prescription for preservation of health in ${\ulcorner}$HuaTuo ZhongZangJing(華陀 中藏經)${\lrcorner}$. It is known to have the effect of Bu-Shen(補腎: strengthening kidney) and Yi-Shou(益壽: prolonging the span of one's life). This study investigates whether JTY is effective on inhibition of oxidation stress. Methods : Sprague-Dawley Rats(12-week-old, weight $300{\pm}20g$) were divided into 3 groups. Normal group(n=8) was injected PBS(1ml/body, s.c) at the back neck's skin. Control group(n=8) was injected D-galactose(50mg/kg, 1ml PBS/body, s.c) to induce pathological animals. JTY group was injected the same treatment for the Control group, and fed containing JTY(10%). The whole groups were treated 1 time per day for 6 weeks. After rats were sacrificed and anti-oxidant enzyme(SOD, CAT, G-px) activity, GSH quantity of RBC and tissue(heart, liver and kidney), plasma Vit-C quantity were examined. Besides, the MDA levels of liver and kidney, lipofuscin of heart and endurance of erythrocyte membrane were measured. Results : In the JTY group, RBC's SOD activity decline was halted by 21% of the normal level, compared to the control group ; G-px activity(unit/g of Hb) increased significantly, compared to the normal group ; and the level of Vit-C in plasma increased by 16%. Heart's SOD activity was kept at the same level as that of the normal group ; and CAT activity decline was halted by 26%. Kidney's CAT and G-px activities were kept at the same level as that shown in the normal group, implying the existence of halting effect. Liver also showed a slight halting effect against the decline of anti-oxidant ability, but the effect was not significant(a=0.05). A comparison between the levels of peroxide in SD rats showed that the level of TBARS in plasma increased significantly in the control group and that it was normal in the JTY group. The livers in the JTY group, compared to those in the control group, showed 36% halting effect of the normal level while their kidney's indicated the level significantly lower than the normal level. Heart's lipofuscin increased significantly in the control group, but was alike in both the JTY and the normal groups. Endurance of erythrocyte membrane(%) decreased significantly in the control group while it was kept at the similar level in both the JTY and the normal groups, indicating the halting effect. Conclusions : This study suggests that JTY is effective to defend oxidation stress caused by D-galactose in the animals. It showed that the anti-oxidant ability was maintained and strengthened. On the other hand, it reduced the level of peroxide in animals. In sum, JTY appeared to have the equilibrium normal physiological function in SD rat.

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Effect of Rainwater Sprinkling System Utilization for Reducing Heat Stress in Milking Cows during Intense Heat Time (폭염시 착유우 고온스트레스 경감을 위한 빗물관수시스템 이용 효과)

  • Choi, Dong-Yoon;Cho, Sung-Back;Park, Kyu-Hyun;Yang, Seong-Hak;Hwang, Ok-Hwa;Kwag, Jung-Hoon;Jeong, Kwang-Hwa;Song, Jun-Ik;Yoo, Yong-Hee;Ahn, Hee-Kwon
    • Journal of Animal Environmental Science
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    • v.18 no.sup
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    • pp.21-28
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    • 2012
  • Since the temperature during summer is higher than the temperature which is suitable for milking cows, high temperature stress have severely affected dairy farmers due to decreased milk production. This study was carried out to investigate the effect of rainwater sprinkling system for reducing heat stress in milking cows during intense heat time. Treatment conditions were divided into 2 types ; No rainwater sprinkling (T1) and Rainwater sprinkling (T2). Temperature in the milking cow shed, feed intake, milk yield, respiration rate and rectal temperature were measured to investigate the effect of hot environment on the physiological, productive responses in milkig cows. The results obtained are summarized as follows : The daily milk yields were 24.5 and 27.4 kg per head in T1 and T2 during experimental period. The respiration rate was significantly higher in T1 than those of T2. The rectal temperature in T1 ($40.6^{\circ}C$) was higher than those of T2 ($39.8^{\circ}C$). It was suggested that rainwater sprinkling system installed in the dairy cow shed was effective means to reduce heat stress of milking cow.

Effects of Different Music Genres on the Stress Levels of Jeju Crossbred Horses (마방에서 음악장르에 따른 Jeju crossbred의 스트레스 변화 연구)

  • Yoonjeong Jang;Jae-Young Choi;Jongan Lee;Yongjun Kang;Nayoung Kim;Minjung Yoon;Moon-Cheol Shin;Sang-Min Shin;Sangsoo Sun;Jiwoong Lee
    • Journal of Life Science
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    • v.33 no.12
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    • pp.995-1001
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    • 2023
  • This study investigated the effects of three music genres (classical, new age, and rock) on the stress levels of six Jeju crossbred horses (Jeju horse × Thoroughbred) in a horse stable. The horses were exposed to the three genres for seven days, and their stress levels were measured by analyzing physiological markers, including neurotransmitter (cortisol, β-endorphin, dopamine, serotonin, and oxytocin) plasma levels and creatine phosphokinase (CPK) and aldolase serum levels. The neurotransmitter analysis showed significant differences in cortisol levels between classical and new age music exposure. Dopamine levels decreased significantly only with new age exposure. Although there were no significant differences in β-endorphin levels between the three genres, β-endorphin levels decreased with increasing classical and new age music playback times and increased with increasing rock music playback times. There were no significant differences in serotonin levels between the three genres. Oxytocin levels decreased significantly with exposure to classical and rock music. The CPK and aldolase analyses showed that CPK levels decreased significantly only with exposure to new age music and increased after playback ended, while aldolase levels decreased significantly with classical and new age music exposure and increased after playback ended. These findings suggest that classical music and new age are the optimal music genres for the psychological stability of Jeju crossbred horses. Playing back an appropriate music genre could be used to improve breeding and promote the welfare of Jeju crossbred horses.

Evaluation of Particle Size Effect on Dynamic Behavior of Soil-pile System (모래 지반의 입자크기가 지반-말뚝 시스템의 동적 거동에 미치는 영향 평가)

  • Han, Jin-Tae;Yoo, Min-Taek;Yang, Eui-Kyu;Kim, Myoung-Mo
    • Journal of the Korean Geotechnical Society
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    • v.26 no.7
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    • pp.49-58
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    • 2010
  • This paper presents experimental results of a series of 1-g shaking table model tests performed on end-bearing single piles and pile groups to investigate the effect of particle size on the dynamic behavior of soil-pile systems. Two soil-pile models were tested twice: first using Jumoonjin sand, and second using Australian Fine sand. In the case of single-pile models, the lateral displacement was almost within 1% of pile diameter which corresponds to the elastic range of the pile. The back-calculated p-y curves show that the subgrade reaction of the Jumoonjin-sand-model ground was larger than that of the Australian Fine-sand-model ground at the same displacement. This phenomenon means that the stress-strain behavior of Jumoonjin sand was initially stiffer than that of Australian Fine sand. This difference was also confirmed by resonant column tests and compression triaxial tests. And the single pile p-y backbone curves of the Australian fine sand were constructed and compared with those of the Jumoonjin sand. As a result, the stiffness of the p-y backbone curves of Jumunjin sand was larger than those of Australian fine sand. Therefore, using the same p-y curves regardless of particle size can lead to inaccurate results when evaluating dynamic behavior of soil-pile system. In the case of the group-pile models, the lateral displacement was much larger than the elastic range of pile movement at the same test conditions in the single-pile models. The back-calculated p-y curves in the case of group pile models were very similar in both sands because the stiffness difference between the Jumoonjin-sand-model ground and the Australian Fine-sand-model ground was not significantly large at a large strain level, where both sands showed non-linear behavior. According to a series of single pile and group pile test results, the evaluation group pile effect using the p-multiplier can lead to inaccurate results on dynamic behavior of soil-pile system.

Neogene Uplift in the Korean Peninsula Linked to Small-scaled Mantle Convection at Singking Slab Edge (소규모 맨틀 대류에 의한 한반도의 신제3기 이후 융기 운동)

  • Shin, Jae-Ryul;Sandiford, Mike
    • Journal of the Korean Geographical Society
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    • v.47 no.3
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    • pp.328-346
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    • 2012
  • This study provides quantitative constraints on Neogene uplift in the Korean peninsula using onshore paleo-shoreline records and seismic data. The eastern margin of Northeast Asia including Korea sits in the back-arc system behind the Western Pacific Subduction Zone, a complex trench triple junction of the Philippine Sea, Pacific, and Eurasian (Amurian) plates. An analysis of seismic data in the subduction zone shows that the pattern of uplift in the peninsula mirrors the extent of deep seismicity in subducting Pacific plate beneath. Combined with previous tomographic studies it is proposed that uplift is partly driven by asthenospheric upwelling caused by a sinking slab during the Neogene. In addition, the SHmax orientations of E-W and N-S trends in the peninsula are consistent with the prevailing in-situ stress fields in the eastern Eurasian continent generated by various plate boundary forces. The uplift in Korea during the Late Neogene is attributed, in part, to lithospheric failure relating to faulting movements, thus providing a link between dynamic effects of mantle upwelling at sinking slab edge and lithospheric responses driven by plate boundary forces.

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The Factors Related to Health Promoting Behaviors of the Late Middle Aged (중년후기 성인의 건강증진행위 관련요인)

  • Lim, Eun Ju;Noh, Jun Hee
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.13 no.10
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    • pp.4694-4702
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    • 2012
  • The purpose of this study was a descriptive research that identified the levels of health-promoting behaviors, previous related behavior, perceived benefits/barriers, self-efficacy, and social support. In addition, it was to establish the relations among the variables, and determine the factors affecting the health-promoting behaviors. Study participants were 311 middle aged between 55-64 in urban areas, and the data were collected through self-reported structured questionnair. According to the results, the mean score for the levels of health-promoting behaviors of the late middle aged was 2.64. Also, among the variables related to health-promoting behaviors, perceived benefits were the highest score (30.7), and perceived barriers were the lowest one (2.08). Meaningful positive correlations were found among health-promoting behaviors and previous related behavior, social support, perceived benefits, and self-efficacy, but perceived barriers showed weakly negative correlations. In addition, the factors affecting health promoting behaviors were revealed in order as following: Previous health related behavior(${\beta}$=.35, p<.001), perceived benefits(${\beta}$=.32, p<.001), social support(${\beta}$=.28, p<.001), and life satisfaction(${\beta}$=.13, p<.001), and this model's explanatory power was 68.8%(F=166.71, p<.001). Based on the findings from the study, in order for the late middle aged to have a well-being old age, an health promoting education program including exercises and stress management should be provided to maintain and improve proper health promoting behaviors. The network with the same age groups also should be supported to share useful information and back up one another.