• Title/Summary/Keyword: Lowering

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Local buckling by lifting and lowering supports in steel box girder bridge (국부좌굴을 고려한 지점 상승 하강 강상자형교)

  • 구민세;정재운;나귀태
    • Proceedings of the Computational Structural Engineering Institute Conference
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    • 2001.10a
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    • pp.227-234
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    • 2001
  • The lifting and lowering supports method was recently developed in steel box girder bridge. It has many advantages by lifting and lowering of inner supports and filled concrete. This method reduces an amount of steel and height of girders. It is one of the methods used to effectively increase the use of structural material. However, if there is too much lifting of inner supports, it is possible to cause buckling of the compression flange or web panel. Therefore it needs a proper number of longitudinal and transvers stiffener.

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The Cumulative Trunk Muscle Fatigue Depending on The Length of Recovery Time (작업 중 여유시간 변화에 따른 몸통 근육 누적 피로도)

  • Shin, Hyun-Joo;Kim, Jung-Yong
    • Journal of Korean Institute of Industrial Engineers
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    • v.33 no.1
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    • pp.44-51
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    • 2007
  • The purpose of this study was to identify the relationship between the cumulative fatigue of trunk muscles andthe period of recovery time during repetitive lifting and lowering tasks with symmetric and asymmetric postures.Ten subjects participated in the experiment. Subjects had 1, 2, 3, 4 and 5 minutes recovery time respectivelywhile they were performing the lifting and lowering task repeatedly for 3 minutes with the weight equivalent to25% level of MVC. EMG signals from ten trunk muscles were collected and the fatigue level was analyzedquantitatively. In results, the local muscle fatigue was no longer accumulated when 5 minutes recovery time wasgiven in symmetric position. For asymmetric position, it took longer minutes to prevent the fatigue accumul-ation. Different trunk muscles indicated slightly different recovery patterns in terms of MPF (Mean Powerfrequency) value.This result would help ergonomist design the length of recovery time to control the cumulative fatigue of trunkmuscles in industry with repetitive lifting and lowering task.

Blood Glucose-Lowering Effects of Mori Folium (상엽의 혈당강하 활성)

  • 이주선;최명현;정성현
    • YAKHAK HOEJI
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    • v.39 no.4
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    • pp.367-372
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    • 1995
  • Mori Folium(MF) methanol extract and its water soluble fraction showed significant blood glucose lowering effects alloxan-induced hyperglycemic mice. Their hypoglycemic activities seemed to nothing to do with the stimulation of insulin release or insulin-like action, according to our experiments. On the other hand, MF prevents the hyperglycemic responses from an oral load of starch and glucose in vivo. Since complex carbohydrates present in a diet must be degraded to monosaccharides by $\alpha$-glucohydrolase before being absorbed in the gastrointestinal tract, it is thought that blood glucose lowering effects of MF may be related to the inhibition of $\alpha$-glucohydrolase catalyzed enzymatic reaction. In addition, experiments that examined an effect of MF water soluble fraction on gastrointestinal movement showed no significant GI movement inhibitory effect. In conclusion, MF water soluble fraction may possess active component which is a potential candidate as an orally active agent for the treatment of diabetes mellitus.

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The Introduction of a Preschool Class as an Alternative to Lowering School Entrance Age: A Case Study of Sweden (스웨덴의 유아학급 설치 사례를 통해 살펴본 취학연령 하향화 대처 방안)

  • Han, You-Me
    • Korean Journal of Human Ecology
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    • v.19 no.4
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    • pp.589-599
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    • 2010
  • When the Korean government announced the lowering of the school entrance age from 6 to 5 years in an effort to increase the fertility rate, one candidate for the Seoul mayor rode on the slogan, 'one dong, one public kindergarten'. This study attempted to show the introduction of a preschool class for six-year-olds being used as analternative to lowering school entrance age in Sweden. First, the current state of preschool class, the Early Childhood Education and Care, and the education system in Sweden were described. Next, the background for the introduction of the preschool classes was analyzed. Thirdly, the effects of preschool class were evaluated from the perspectives of 6 year-olds as well as the institutiona land social status of the ECEC. Results from this study imply not only that the lower school entrance age policy should be abolished but also preschool classes could be considered as an alternative.

Impact of Energy Relaxation of Channel Electrons on Drain-Induced Barrier Lowering in Nano-Scale Si-Based MOSFETs

  • Mao, Ling-Feng
    • ETRI Journal
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    • v.39 no.2
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    • pp.284-291
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    • 2017
  • Drain-induced barrier lowering (DIBL) is one of the main parameters employed to indicate the short-channel effect for nano metal-oxide semiconductor field-effect transistors (MOSFETs). We propose a new physical model of the DIBL effect under two-dimensional approximations based on the energy-conservation equation for channel electrons in FETs, which is different from the former field-penetration model. The DIBL is caused by lowering of the effective potential barrier height seen by the channel electrons because a lateral channel electric field results in an increase in the average kinetic energy of the channel electrons. The channel length, temperature, and doping concentration-dependent DIBL effects predicted by the proposed physical model agree well with the experimental data and simulation results reported in Nature and other journals.

Isolation and characterization of cholesterol-lowering lactic acid bacteria from kimchi (김치에서 분리된 콜레스테롤 감소능을 가진 젖산세균의 특성)

  • Park, Hong-Yeop;Park, Seul-Ki;Kim, Bo-Geum;Ryu, Dae-Gyu;Lim, Eun-Seo;Kim, Young-Mog
    • Korean Journal of Food Science and Technology
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    • v.49 no.4
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    • pp.377-382
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    • 2017
  • The objective of this study was to isolate and characterize lactic acid bacteria (LAB) exhibiting cholesterol-lowering activity from the Korean traditional fermented food, kimchi. The previously isolated LAB strains were assessed for cholesterol-lowering efficacy in the presence of 0.1% cholesterol. All LAB strains tested in this study were able to assimilate cholesterol at varying levels, ranging from 35.0 to 99.4%. Among them, the Lactobacillus plantarum FMB 31 strain exhibited the highest cholesterol-lowering effect with 99.4% cholesterol removal efficiency. The strain was stable in the presence of acid, bile, and salt stress, and showed high adherence on HT-29 cells, a human colon line. In addition, the LAB strain showed no pathogenic properties such as the production of hemolysin and biogenic amines. Thus, this study suggests that the L. plantarum FMB 31 strain isolated from kimchi can be a potential source of probiotic products with strong cholesterol-lowering effect.

Effect of Food Humectant on Lowering Water Activity of Casing Kamaboko. 2. Effect of Lowering Water Activity of Starch, Glycine and Sodium Lactate and Prediction of the Water Activity Lowering Ability of Humectants (포장 어묵의 수분활성 저하에 미치는 식품첨가제의 영향 2. 전분류, glycine, sodium lactate의 영향 및 어목의 수분활성예측법)

  • KIM Dong-Soo;PARK Young-Ho
    • Korean Journal of Fisheries and Aquatic Sciences
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    • v.15 no.1
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    • pp.74-82
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    • 1982
  • In the previous study, we have reported the effect of lowering water activity of sodium chloride, sugars and polyols. In this study, water activity($a_w$)of various model Preparations of Kamaboko was measured and ability of lowering $a_w$ of starch, glycine and sodium lactate was discussed. In addition, the aw measurements were also compared to the predicted values of au which were derived from the equation of Raoult's law and the linear slope method by Sloan ana Labuza. The effect of starch on lowering $a_w$ was very low, and glycine was more effective than starch. Sodium lactate was shown to be the most effective among humectants examined. When it was added by $7.5\%$, the $a_w$ of model Kamaboko A was reduced to 0.93-0.94. Generally, prediction by the equation of Raoult's law turned out to be useful for determining $a_w$ lowering effect of humectants, excepting sodium chloride and sodium lactate. The equation of regression derived from the least squares could be applied to Predicting au in the model Kamaboko.

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Guidelines on the Operation Phases of Manual Material Handling Tasks Through Literature Reviews

  • Lee, Kyung-Sun;Jung, Myung-Chul
    • Journal of the Ergonomics Society of Korea
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    • v.36 no.4
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    • pp.325-341
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    • 2017
  • Objective: The purpose of this study is to suggest the guidelines of operation phases to minimize injuries and musculoskeletal disorders in manual material handling (MMH) tasks through literature reviews. The guidelines are presented as the preparing phase, lifting phase, carrying phase, and lowering phase. Also, we summarized the non-numerical general guidelines for MMH tasks. Background: Manual material handling is still a main cause to musculoskeletal disorders. Method: Procedures of a literature review are classified into database selection, keyword search, title review, abstract review related to literature selection, guideline review and arrangement. A total 48 papers and books were analyzed in detail by title and abstract reviews. Results: In the preparing phase, we suggested the basic conditions in MMH, preparing procedure, clothing and protective equipment, and education. In the lifting and carrying phases, we recommended maximal acceptable weight by frequency and body posture. In the lowering phase, we suggested the lowest weight and safety body postures. Finally, we recommended general guidelines and guideline items for MMH. General guidelines are presented to suggest worker selection, technical education, and work design parts. Conclusion: We suggested the guidelines on the four operation phases of MMH tasks such as preparing, lifting, carrying, and lowering phases. Application: The findings of this study can be utilized as guidelines for proactive recommendations according to workers in MMH tasks.

Psychophysical modeling for one-handed combined tasks (한손 연속작업의 심리육체학적 모델링)

  • 윤훈용
    • Proceedings of the ESK Conference
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    • 1997.04a
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    • pp.95-99
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    • 1997
  • Most studies in manual material handling (MMH) have paid more attention to single MMH activities-lifting, lowering, carrying, holding, pushing or pulling and have ignored combined activities. Also, many studies have been involved with two-handed MMH activities rather than to one-handed MMH activities. Very few studies are reported on the determination of workers' capacities for combinations of one-handed MMH activities (e.g. lifting a box, then carrying the box, and lowering the box). The objective of this study was to utilize the psychophysical approach to examine the combinations of lifting, carrying and lowering activities from a simulated industrial task involving one- handed and two-handed combined tasks and to develop mathematical models for combined tasks. Ten male students served as subjects for the study. The capacities that were determined as the maximum acceptable weight workloads for 1 hr work period for one-handed and two-handed combined tasks-lifting a box from floor to knuckle height, carrying the box for 4.3 m, and lowering the box form knuckle to floor height -were determined psychophysically under three frequencies: six handlings per minute, one handling per minute and one handling per five minutes. Combined MMH capacities models for one-handed tasks were developed. Te advantages and disadvantages of different models are discussed.

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Visual Biofeedback to Monitor Serratus Anterior and Upper Trapezius Muscle Activities During Arm Lowering (팔 내리기 동작 시 시각적 바이오피드백 훈련이 전거근과 상부 승모근의 근활성도에 미치는 영향)

  • Ha, Sung-Min;Min, Kyung-Jin;Choi, Houng-Sik
    • Physical Therapy Korea
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    • v.15 no.2
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    • pp.38-43
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    • 2008
  • To reduce winging scapula, various exercise protocols have been widely used by clinicians. Selective serratus anterior strengthening, and restoring balanced function, are especially recommended to reduce winging scapula. The purpose of this study was to investigate visual biofeedback using a real time video camera display system for monitoring scapular winging during arm lowering. For this study, 13 males with winging scapular were recruited during arm lowering. Electromyography (EMG) activity was recorded from the serratus anterior (SA) and upper trapezius (UT) of the right side and compared with normal EMG activity using a paired t-test. The study showed, through visual biofeedback, that EMG activity significantly increased in the SA and significantly decreased in the UT (p<.05). These results suggest that visual biofeedback can be recommended as an effective method for scapular eccentric control, to prevent scapular winging during arm lowering.

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