• Title/Summary/Keyword: Side condition

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Operational modal analysis of a long-span suspension bridge under different earthquake events

  • Ni, Yi-Qing;Zhang, Feng-Liang;Xia, Yun-Xia;Au, Siu-Kui
    • Earthquakes and Structures
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    • v.8 no.4
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    • pp.859-887
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    • 2015
  • Structural health monitoring (SHM) has gained in popularity in recent years since it can assess the performance and condition of instrumented structures in real time and provide valuable information to the asset's manager and owner. Operational modal analysis plays an important role in SHM and it involves the determination of natural frequencies, damping ratios and mode shapes of a constructed structure based on measured dynamic data. This paper presents the operational modal analysis and seismic response characterization of the Tsing Ma Suspension Bridge of 2,160 m long subjected to different earthquake events. Three kinds of events, i.e., short-distance, middle-distance and long-distance earthquakes are taken into account. A fast Bayesian modal identification method is used to carry out the operational modal analysis. The modal properties of the bridge are identified and compared by use of the field monitoring data acquired before and after the earthquake for each type of the events. Research emphasis is given on identifying the predominant modes of the seismic responses in the deck during short-distance, middle-distance and long-distance earthquakes, respectively, and characterizing the response pattern of various structural portions (deck, towers, main cables, etc.) under different types of earthquakes. Since the bridge is over 2,000 m long, the seismic wave would arrive at the tower/anchorage basements of the two side spans at different time instants. The behaviors of structural dynamic responses on the Tsing Yi side span and on the Ma Wan side span under each type of the earthquake events are compared. The results obtained from this study would be beneficial to the seismic design of future long-span bridges to be built around Hong Kong (e.g., the Hong Kong-Zhuhai-Macau Bridge).

Predictions of Microscale Separated Flow using Langmuir Slip Boundary Condition (Langmuir 미끄럼 경계조건을 이용한 미소 박리유동의 예측)

  • Lee, Do-Hyung;Meang, Joo-Sung;Choi, Hyung-Il;Na, Wook-Sang
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.27 no.8
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    • pp.1097-1104
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    • 2003
  • The current study analyzes Langmuir slip boundary condition theoretically and it is tested in practical numerical analysis for separation-associated flow. Slip phenomenon at the channel wall is properly implemented by various numerical slip boundary conditions including Langmuir slip model. Compressible backward-facing step flow is compared to other analysis results with the purpose of diatomic gas Langmuir slip model validation. The numerical solutions of pressure and velocity distributions where separation occurs are in good agreement with other numerical results. Numerical analysis is conducted for Reynolds number from 10 to 60 for a prediction of separation at T-shaped micro manifold. Reattachment length of flows shows nonlinear distribution at the wall of side branch. The Langmuir slip model predicts fairly the physics in terms of slip effect and separation.

Etching behavior of electroetching by using photomask (Photomask를 이용한 electroetching의 부식거동)

  • 김동규;이홍로
    • Journal of the Korean institute of surface engineering
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    • v.28 no.2
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    • pp.101-109
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    • 1995
  • Electroetching rates of $FeCl_3$ solution were increased according to increasing solution temperature. Activation energy of electroetching at Be'36 and 5A/$dm^2$ condition was 28.3Kcal and also, at Be'46 and 5A/dm$^2$ condition was 33.2Kcal. At Be'36 concentration of $FeCl_3$ solution, electroetching rate were more higher than at Be'46 concentration. Surfaces of etched grooves obtained at 8A/$dm^2$ or higher current density in 46 Be' concentration of $FeCl_3$ solution were observed to be flat and smooth owing to suppressing chemical etching reaction. Distinctly etched boundaries became to be appeared at 2A/$dm^2$ in Be'41 electroetching condition by differential effects. In case of applying 8A/$dm^2$ current density to Be'46 of $FeCl_3$ solution, etching depth were 4 times and side etching were 6 times more than chemical etching case respectively.

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Thermal Environment Analysis of a Room in Accordance with Ventilation Condition with Multi-Heat Sources (다수의 열원을 가지는 공간에서의 환기 조건에 따른 열환경 해석)

  • Kim, Jae-Jung;Son, Young-Gap;Chang, Seog-Weon;Ryu, Dong-Su
    • Proceedings of the KSME Conference
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    • 2000.11b
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    • pp.199-204
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    • 2000
  • This paper reports a thermal environmental analysis of a room in accommodated with multi-heat sources according to ventilation condition. Two case modification have been investigated to obtain the lower temperature distribution in the room. The temperature distribution of the original room were found about $25{\sim}35^{\circ}C$. As a result, the use of, three ventilating fans and two electric fans are useful for room ventilation respectively, and using two electric fan is more recommendable in side of economical efficiency.

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Numerical Study for the Effect of Inlet Humidity Condition at PEMFC Channel (전산해석을 통한 고분자 전해질 연료전지 내 입구 가습조건의 영향에 관한 연구)

  • Lee Dong-Ryul;Ahmed Dewan Hasan;Bae Joong-Myeon
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.30 no.12 s.255
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    • pp.1228-1235
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    • 2006
  • PEMFC(Proton Exchange Membrane Fuel Cell) is a low temperature fuel cell and has many probabilities of commercial use. However, water management is one of the serious technical problems for commercialization. It is necessary to understand the relationship between operation conditions and water behavior in PEMFC channel because it affects fuel cell performance. In this paper, the distribution of current density according to inlet humidity condition is mainly observed and discussed. If the anode inlet is well humidified, electro-osmotic drag is very active. For this reason, current density is very high at inlet side and the distribution is non-uniform.

Analysis of Field Condition for Proper Waterproofing Materials applied to Green Roof System for Depot (도시철도 차량기지의 기반녹화에 적합한 방수시스템 선정을 위한 환경 조건 분석)

  • Min, Kwang-Man;Kwon, Shi-Won;Choi, Sung-Min;Kwak, Kyu-Sung;Oh, Sang-Keun
    • Proceedings of the Korean Institute of Building Construction Conference
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    • 2006.11a
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    • pp.127-131
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    • 2006
  • Depot have a lagged behind structure in the side of building up the view. With this reason, people have been recognized depot as hatred facility causes to have car noise, air pollution. In the other hand, depot become a underground and complex facility as a higher-value added building, and moreover, it need to understand the environment that depot structure have a specific field condition to apply green roof system. 1) Analysis proper waterproofing material and root barrier apply to depot need root penetrating test method 2) Suggest root barrier and waterproofing material relate to maintain and construction for green roof system 3) Construction condition for depot have crack movement of structure by vehicle vibration and root penetrating force by plant growth

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The Numerical Analysis on the Behaviour of Combined Sheet Pile in the Reclaimed Ground Mixed by Sandy Soil and Clayey Soil (사질토와 점성토가 혼재하는 해안 매립지반에서 조합형 Sheet Pile의 거동에 관한 해석적 연구)

  • Kim, Byung-Il;Kim, Young-Sun;Han, Sang-Jae;Park, Eon-Sang
    • Journal of the Korean Geosynthetics Society
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    • v.19 no.3
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    • pp.9-21
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    • 2020
  • In this study, the design method of the combined sheet pile was considered in the coastal landfill where sandy and clayey soils are mixed, and the behavior in excavation was analyzed. It was confirmed from the elasto-plastic analysis that the predicted behavior of the temporary facilities of earth retaining differs according to the type of the combined sheet pile method (Built up, Interlocking, Welding) and the analysis method (soldier pile method, continuous wall method). In the case of sheet pile member force, the results of the continuous wall analysis method predicted the most conservative results. When the stress ratio (calculation/allowance) of each member was analyzed based on the maximum member force of the combined sheet pile method, the maximum value was obtained for bending moment in the side pile and combined stress in the case of the strut. As a result of finite element analysis, the member force of the side pile was the largest in the short-term effective stress analysis condition, while the compressive force of the strut was large in the consolidation analysis. When comparing the results of the elasto-plastic analysis and the finite element analysis, the shear force of the side pile and the axial force of the strut were greatly evaluated in the elasto-plastic analysis, and the bending moment of the side pile was the largest in the short-term effective stress condition of the finite element analysis. In addition, the displacement of the side pile was predicted to be greater in the finite element analysis than in the elasto-plastic analysis.

Relationships between the Nutritional Status for Lunch-Box, the Taste of Food and the Environmental Factors of Middle School Girls in Kwangju City (광주시내 여중학생의 도시락 영양실태와 식품 기호 및 환경요인과의 관계)

  • 안순례
    • Journal of the Korean Home Economics Association
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    • v.26 no.3
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    • pp.53-68
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    • 1988
  • This article concerned with the nutritional status and the taste of the lunch box of 311 middle school girls in Kwangju City from May 18 to June 12 in 1987. The purpose of this research was making materials to show direction of the education about nutrition by checking relationships among the nutritional status for the lunch box, the taste of food and the environmental factors. The results observed in the study were as follows: 1. The intake of nutrition from the lunch box and the ratio between the recommended dietary allowance and the contained nutrients in the lunch box as follows. Calorie(603 Kcal, 78.6%), protein (21.7g, 93.1%) Animal protein (10.3g, 132.1%) calcium (151.7 g, 56.9%) Ferrum 93.1 mg, 51.7%), Vitamin a (129.3 RE, 55.4%) Vitamin B1 (0.29 mg, 72.5%), Vitamin B (0.26 mg, 55.3%) Niacin (4.7 mg, 94.0%), Vitamin C 913.2 mg, 79.0%). Except animal protein, all the recommended dietary allowance. 2. According to the intake of calorie, the ratio of taken carbohydrate, protein and fat was 77.7 : 15.5 : 6.8. The intake of protein was desirable but most of calorie depended on carbohydrate. Among the total intake of protein, the ratio of animal protein was 47.5%, which was a high rate. 3. Most of calorie (75%), was taken from staples, protein (41.5%), vitamin B1 (48.3%) were taken at the same rate from staples and side dishes. Most of fat, calcium, ferrum, vitamin A, vitamin B, and vitamin C, was taken from side dishes. 4. In taking among the five basic food groups, proportion of the grain fourth food group was the highest, light color vegetable the third food groups, proportion of the grain fourth food group was the highest, light color vegetable the third food group was second, and Calcium food the second food group was the lowest. 5. As the staples, students liked tchajangmyon, mandu and ttokkuk as written order. They disliked Kongbap and Patpap. As the side dishes for the lunch box, they liked kimchi, ham, sausage, cuttlefish, dried slices of filefish, eggs and green seaweed as written order. As a side dishes they liked Laver, Cucumber, Squid, lettuce, Potatoes. They disliked pork fat, cow's intestines, cow's liver, Crussian carp, pickled fish. The favorite snack was fruits, ice cream, hamburger, Chocolate and milk. 6. In taking condition of the principal food, rice rate (65.6%) was the most, and mixed food was 5 or 10%. 7. Favorite cooking was frying, roasting and kimch. But disagreeable cooking was pickling. 8. Favorite food was what was pungent but disagreeable food was what was salty. 9. the higher parents educational background was, the higher their income was. Also the more various the information about the nutrition was, the better the intake of nutrition was. 10. The preference tendency influenced in choosing the side dish of the Lunch box. The higher the preference tendency of the girl students became, the better their nutrition condition became.

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RADIATION SAFETY ASSESSMENT FOR KN-12 SPENT NUCLEAR FUEL TRANSPORT CASK USING MONTE CARLO SIMULATION

  • Kim, J.K.;Kim, G.H.;Shin, C.H.;Choi, H.S.
    • Journal of Radiation Protection and Research
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    • v.26 no.3
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    • pp.207-214
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    • 2001
  • The KN-12 spent nuclear fuel (SNF) transport cask is designed for transportation of up to 12 assemblies and is in standby status for being licensed in accordance with Korea Atomic Energy Act. To evaluate radiation shielding and criticality safety of the KN-12 cask, each case of study was carried out using MCNP4B Code. MCNP code is verified by performing benchmark calculation for the KSC-4 SNF cask designed in 1989. As a result of radiation safety evaluation for the KN-12 cask, calculated dose rates always satisfied the standards at the cask surface, at 2m from the surface in normal transport condition, and at 1 m from the surface in hypothetical accident condition. Maximum dose rate was always arisen on the side of the cask. For normal transport condition, photons primarily contribute to dose rate between two kinds of released sources, neutrons and photons, from spent nuclear fuel but for hypothetical accident condition, contrary case was resulted. The level of calculated dose rate was 27.8% of the limit at the cask surface, 89.3% at 2 m from the cask surface, and 25.1% at 1 m from the cask surface. For criticality analysis, keff resulting from the criticality analysis considering the condition of optimum partial flooding with fresh water is 0.89708(0.00065. The results confirm the standards recommended by all regulations on radiation safety.

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A Study on the EMG Activity of Abdominal Muscles with Stable and Unstable Bridging Exercises in Individuals with Healthy Subjects

  • Lee, Jun Cheol
    • Journal of International Academy of Physical Therapy Research
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    • v.8 no.1
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    • pp.1077-1083
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    • 2017
  • The purpose of this study was to investigate the effects of stable and unstable bridging exercises on the EMG activity of abdominal muscles. Twenty healthy women participated in this study and the muscle activities of left-right rectus abdominis (RA), external oblique (EO), and internal oblique (IO) muscles were recorded during 4 bridging exercises (unilateral/ bilateral, stable/unstable). The activity of the right EO muscle was the highest during unilateral exercise in unstable condition, and left EO muscle also produced the same result. The activity of the right IO muscle was the highest during unilateral exercise in an unstable condition, and left IO muscle also produced the same result. The activity of the right RA muscle was the highest during unilateral exercise in a stable condition, and left RA muscle produced the same result. Unstable/unilateral (USUL) represented the highest activity among the 4 exercises. EO/IO muscles represented the highest activity during the USUL exercise, and RA did so during the stable/unilateral exercise. These results suggest that specific posture (USUL) can be administered targeting a specific side of abdominal muscles.