• Title/Summary/Keyword: sagA

Search Result 560, Processing Time 0.04 seconds

Analytical Study of Geometric Nonlinear Behavior of Cable-stayed Bridges (사장교의 기하학적 비선형 거동의 해석적 연구)

  • Kim, Seungjun;Lee, Kee Sei;Kim, Kyung Sik;Kang, Young Jong
    • KSCE Journal of Civil and Environmental Engineering Research
    • /
    • v.30 no.1A
    • /
    • pp.1-13
    • /
    • 2010
  • This paper presents an investigation on the geometric nonlinear behavior of cable-stayed bridges using geometric nonlinear finite element analysis method. The girder and mast in cable-stayed bridges show the combined axial load and bending moment interaction due to horizontal and vertical forces of inclined cable. So these members are considered as beam-column member. In this study, the nonlinear finite element analysis method is used to resolve the geometric nonlinear behavior of cable-stayed bridges in consideration of beam-column effect, large displacement effect (known as P-${\delta}$ effect) and cable sag effect. To analyze a cable-stayed bridge model, nonlinear 6-degree of freedom frame element and nonlinear 3-degree of freedom equivalent truss element is used. To resolve the geometric nonlinear behavior for various live load cases, the initial shape analysis is performed for considering dead load before live load analysis. Then the geometric nonlinear analysis for each live load case is performed. The deformed shapes of each model, load-displacement curves of each point and load-tensile force curves for each cable are presented for quantitative study of geometric nonlinear behavior of cable-stayed bridges.

Characterization of In(Al)GaN layer grown by mixed-source hydride vapor phase epitaxy (혼합소스 HVPE에 의해 성장된 In(Al)GaN 층의 특성)

  • Hwang, S.L.;Kim, K.H.;Jang, K.S.;Jeon, H.S.;Choi, W.J.;Chang, J.H.;Kim, H.S.;Yang, M.;Ahn, H.S.;Bae, J.S.;Kim, S.W.
    • Journal of the Korean Crystal Growth and Crystal Technology
    • /
    • v.16 no.4
    • /
    • pp.157-161
    • /
    • 2006
  • InGaN layers on GaN templated sapphire (0001) substrates were grown by mixed-source hydride vapor phase epitaxy (HVPE) method. In order to get InGaN layers, Ga-mixed In metal and $NH_3$ gas were used as group III and group V source materials, respectively. The InGaN material was compounded from chemical reaction between $NH_3$ and indium-gallium chloride farmed by HCl flowed over metallic In mixed with Ga. The grown layers were confirmed to be InGaN ternary crystal alloys by X-ray photoelectron spectroscopy (XPS). In concentration of the InGaN layers grown by selective area growth (SAG) method was investigated by the photoluminescence (PL) and cathodoluminescence (CL) measurements. Indium concentration was estimated to be in the range 3 %. Moreover, as a new attempt in obtaining InAlGaN layers, the growth of the thick InAlGaN layers was performed by putting small amount of Ga and Al into the In source. We found the new results that the metallic In mixed with Ga (and Al) as a group III source material could be used in the growth process of the In(Al)GaN layers by the mixed-source HVPE method.

Self-purification Capacity of Eutrophic Buk Bay by DO mass Balance (부영양화된 북만의 용존산소 수지에 의한 자정능력)

  • CHOI Woo-Jeung;NA Gui-Hwan;CHUN Young-Yell;PARK Chung-Kil
    • Korean Journal of Fisheries and Aquatic Sciences
    • /
    • v.24 no.1
    • /
    • pp.21-30
    • /
    • 1991
  • In Summer, oxygen-deficient water masses were developed extensively in the closed eutrophic bays such as Chinhae Bay which results in mass mortality of marine organisms and severe decrease the production of the bay every year. Under the circumstances, this study was performed to investigate the oxygen depletion relating to eutrophication, and also to evaluate self-purfication capacity of Buk Bay by dissolved oxygen mass balance in 1988. The mean concentration of total inorganic nitrogen, phosphate phosphorus and chlorophyll-a were $11.06{\mu}g-at/l,\;0.80{\mu}g-at/l\;and\;1.11mg/m^3$ respectively, which were over eutrophication criteria. Oxygen-deficient water mass was formed in July with the minimum concentration of 2.08ml/l(mean) at the bottom of all stations and recovered slowly in August. The decay and reaeration coefficient calculated from dissloved oxygen sag curve were 0.222/day and 0.018ml/l/day, respectively. To maintain above 4ml/l of oxygen to prevent oxygen-deficient water mass, it is recommendable to supply as much as 0.856ml/l/day of dissolved oxygen or should be reduced the same mass loading of BOD from watershed by the construction of wastewater treatment plant.

  • PDF

A study on the development and the physical properties of Epoxy Putty for earthenware restoration (토기 복원용 Epoxy Putty 개발 및 물성에 관한 연구)

  • Bae, Jin Soo;Cheong, Da Som;Kim, Woo Hyun;Kang, Seok In;Wi, Koang Chul
    • Journal of Conservation Science
    • /
    • v.30 no.1
    • /
    • pp.103-109
    • /
    • 2014
  • This study aimed to develop materials to compensate for problems of restoration for lost parts and material problems in the conservation treatment. First, there are several problems with existing materials as follows: secondary damage due to the high shrinkage rate and low adhesive strength, sense of difference due to the severe yellowing, remelting due to irreversibility of materials, processability due to the high strength, sag due to the prolonged setting time in the work process and surface contamination of artifacts due to tools or gloves. In order to solve these problems, this study set developmental goals after understanding the types and physical properties based on epoxy resin among the currently used restoration materials of pottery and earthenware. The developed epoxy resin is epoxy putty, which is cured within 5 minutes, for earthenware restoration. In the earthenware restoration method, the epoxy putty enhanced the workability by quickly curing in paste form and compensated disadvantages such as surface contamination. In addition, the use of white micro-balloon for the epoxy stock solution made coloring easier and weight lighter, and a restoration material with low shrinkage and superior processability was developed.

Optimum Dumping Rate of Biodegradable Liquid Waste in Ocean Disposal (분해성 액상폐기물의 해양처리시 최적 투기율)

  • LEE Suk-Mo
    • Korean Journal of Fisheries and Aquatic Sciences
    • /
    • v.23 no.3
    • /
    • pp.198-207
    • /
    • 1990
  • Among the biodegradable liquid waste treatment and disposal methods, ocean dumping is a cost-effective and productive manner considering reuse point of view However, when biodegradable liquid waste is dumped in the ocean, oxygen consumption by the decomposition of organic matter must be considered. The purpose of this study is to determine the maximum allowable concentration and dumping rate in the southern waters of the East Sea based on dissolved oxygen level. Streeter and Phelps' model has been used to determine the maximum allowable concentration. Factors in this model, deoxygenation constants and reaeration coefficients, have been determined by appling oxygen consumption method and closed system model. Deoxygenation constants and reaeration coefficients from surface to each standard depth are $0.24\~0.29/day\;and\;0.03\~0.39/day$ in summer, $0.17\~0.20/day\;and\;0.04\~0.56/day$ in winter, respectively. The allowable organic matter concentration($mgBOD/\iota$) to the dissolved oxy-gen sag value of $5mg/{\iota}$ is represented $17.23\times(H)^{-0.37}$ in summer, and $64.96\times(H)^{-0.52}$ in winter by mixing depth(H, m). Csanady's experiment has been applied to estimate the optimum dumping rate. The optimum dumping rate($R,\;m^3/sec$) can be written as a product of the beam(b, m) and the draft(h, m) of vessel, and biochemical oxygen demand of waste($L_n,\;mg/{\iota}$) $R=275{\times}bh^{0.63}L_n^{-1}$ in summer $=745{\times}bh^{0.48}L_n^{-1}$ in winter. The difference of dumping rate between in summer and winter is due to the oxygen distribution.

  • PDF

Distribution of Natural Frequency of 2-DOF Approximate Model of Stay Cable to Reduction of Area (단면감소에 따른 사장케이블의 2-자유도 근사모델의 고유진동수 분포)

  • Joe, Yang-Hee;Lee, Hyun-Chol
    • Journal of the Korea institute for structural maintenance and inspection
    • /
    • v.18 no.6
    • /
    • pp.147-154
    • /
    • 2014
  • The cable damages of the bridge structures induce very important impact on the structural safety, which implies the close monitoring of the cable damage is required to secure sustained safety of the bridges. Most usual available maintenance techniques are based on the monitoring the change of the natural frequency of the structures by damages. However, existing method are based on vibration method to calculate lateral vibration and system identification can calculate the axial stiffness using sensitivity equation by trial error method. But the frequency study by the longitudinal movement need because of the sag effect in system identification. This study proposes a new method to investigate the damage magnitudes and status. The method improves the accuracies in the magnitudes and status of damages by adopting the natural frequency of longitudinal movement. The study results have been validated by comparing them with the approximate solution of FEM. Thus, the relationship of cable damage and frequency appear with relation that the severe damage has the little frequency. If we know the real frequency we can estimate the cable damage severity using this relationship. This method can be possible the efficient management of the cable damage.

Differences in Infant Problem Behaviors According to Adult Attachment and Parenting Attitudes of Mother (어머니의 성인애착과 양육태도에 따른 유아의 문제행동에서의 차이)

  • Lee, Seung Hee;Kim, Sag Ok
    • Korean Journal of Child Education & Care
    • /
    • v.19 no.1
    • /
    • pp.75-86
    • /
    • 2019
  • Objective: The study looked at the relationship between the mother's adult attachment, the children's problematic behavior and the mother's nurturing attitude. In doing so, this study tried to determine whether the mother's nurturing attitude would play a moderating role in the context of the effect of mother' adult attachment on the children's problematic behavior. Methods: we surveyed 352 mothers of 3~5 year old infants who were financially dependent on day care centers. Results: The problematic behavior of being daunted is high when mothers' adult attachment of avoidance is high and when mothers have low level of controlling pattern in their nurturing of their children. The problematic behavior of anxiety and depression was observed when adult attachment of anxiety was high and low level of controlling pattern in their nurturing. Meanwhile, when the externalized problematic behaviors were examined, no interaction effect of mothers' adult attachment and nurturing pattern was observed in all sub-levels of the children's externalized problematic behaviors. Conclusion/Implications: We could see how the influence of parenting attitude appears in mothers with unstable adult attachment. In addition, mothers with unstable adult attachment may be able to confirm that the quality of the interaction of the parent-child relationship and the form of the child's problem behavior differ according to the level of the mother's parenting attitude in the child's problem behavior. The results of this study showed that mothers with unstable adult attachment differed in the form of problem behaviors of infants according to mother's parenting attitude in infant problem behaviors.

Microscopic Traffic Analysis of Freeway Based on Vehicle Trajectory Data Using Drone Images (드론 영상을 활용한 차량궤적자료 기반 고속도로 미시적 교통분석)

  • Ko, Eunjeong;Kim, Soohee;Kim, Hyungjoo
    • The Journal of The Korea Institute of Intelligent Transport Systems
    • /
    • v.20 no.6
    • /
    • pp.66-83
    • /
    • 2021
  • Vehicles experience changes in driving behavior due to the various facilities on the freeway. These sections may cause repetitive traffic congestion when the traffic volume increases, so safety issues may be raised. Therefore, the purpose of this study is to perform microscopic traffic analysis on these sections using drone images and to identify the causes of traffic problems. In the case of drone image, since trajectory data of individual vehicles can be obtained, empirical analysis of driving behavior is possible. The analysis section of this study was selected as the weaving section of Pangyo IC and the sag section of Seohae Bridge. First, the trajectory data was extracted through the drone image. And the microscopic traffic analysis performed on the speed, density, acceleration, and lane change through cell-unit analysis using Generalized definition method. This analysis results can be used as a basic study to identify the cause of the problem section in the freeway. Through this, we aim to improve the efficiency and convenience of traffic analysis.

Stratigraphic response to tectonic evolution of sedimentary basins in the Yellow Sea and adjacent areas (황해 및 인접 지역 퇴적분지들의 구조적 진화에 따른 층서)

  • Ryo In Chang;Kim Boo Yang;Kwak won Jun;Kim Gi Hyoun;Park Se Jin
    • The Korean Journal of Petroleum Geology
    • /
    • v.8 no.1_2 s.9
    • /
    • pp.1-43
    • /
    • 2000
  • A comparison study for understanding a stratigraphic response to tectonic evolution of sedimentary basins in the Yellow Sea and adjacent areas was carried out by using an integrated stratigraphic technology. As an interim result, we propose a stratigraphic framework that allows temporal and spatial correlation of the sedimentary successions in the basins. This stratigraphic framework will use as a new stratigraphic paradigm for hydrocarbon exploration in the Yellow Sea and adjacent areas. Integrated stratigraphic analysis in conjunction with sequence-keyed biostratigraphy allows us to define nine stratigraphic units in the basins: Cambro-Ordovician, Carboniferous-Triassic, early to middle Jurassic, late Jurassic-early Cretaceous, late Cretaceous, Paleocene-Eocene, Oligocene, early Miocene, and middle Miocene-Pliocene. They are tectono-stratigraphic units that provide time-sliced information on basin-forming tectonics, sedimentation, and basin-modifying tectonics of sedimentary basins in the Yellow Sea and adjacent area. In the Paleozoic, the South Yellow Sea basin was initiated as a marginal sag basin in the northern margin of the South China Block. Siliciclastic and carbonate sediments were deposited in the basin, showing cyclic fashions due to relative sea-level fluctuations. During the Devonian, however, the basin was once uplifted and deformed due to the Caledonian Orogeny, which resulted in an unconformity between the Cambro-Ordovician and the Carboniferous-Triassic units. The second orogenic event, Indosinian Orogeny, occurred in the late Permian-late Triassic, when the North China block began to collide with the South China block. Collision of the North and South China blocks produced the Qinling-Dabie-Sulu-Imjin foldbelts and led to the uplift and deformation of the Paleozoic strata. Subsequent rapid subsidence of the foreland parallel to the foldbelts formed the Bohai and the West Korean Bay basins where infilled with the early to middle Jurassic molasse sediments. Also Piggyback basins locally developed along the thrust. The later intensive Yanshanian (first) Orogeny modified these foreland and Piggyback basins in the late Jurassic. The South Yellow Sea basin, however, was likely to be a continental interior sag basin during the early to middle Jurassic. The early to middle Jurassic unit in the South Yellow Sea basin is characterized by fluvial to lacustrine sandstone and shale with a thick basal quartz conglomerate that contains well-sorted and well-rounded gravels. Meanwhile, the Tan-Lu fault system underwent a sinistrai strike-slip wrench movement in the late Triassic and continued into the Jurassic and Cretaceous until the early Tertiary. In the late Jurassic, development of second- or third-order wrench faults along the Tan-Lu fault system probably initiated a series of small-scale strike-slip extensional basins. Continued sinistral movement of the Tan-Lu fault until the late Eocene caused a megashear in the South Yellow Sea basin, forming a large-scale pull-apart basin. However, the Bohai basin was uplifted and severely modified during this period. h pronounced Yanshanian Orogeny (second and third) was marked by the unconformity between the early Cretaceous and late Eocene in the Bohai basin. In the late Eocene, the Indian Plate began to collide with the Eurasian Plate, forming a megasuture zone. This orogenic event, namely the Himalayan Orogeny, was probably responsible for the change of motion of the Tan-Lu fault system from left-lateral to right-lateral. The right-lateral strike-slip movement of the Tan-Lu fault caused the tectonic inversion of the South Yellow Sea basin and the pull-apart opening of the Bohai basin. Thus, the Oligocene was the main period of sedimentation in the Bohai basin as well as severe tectonic modification of the South Yellow Sea basin. After the Oligocene, the Yellow Sea and Bohai basins have maintained thermal subsidence up to the present with short periods of marine transgressions extending into the land part of the present basins.

  • PDF

Preparation of Low Methoxyl Pectins by Pectinesterase in Tangerine Albedo and their Chemical, Physical and Gelling Properties (감귤류 과피내의 Pectinesterase 작용에 의한 Low Methoxyl Pectin 조제 및 특성에 관한 연구)

  • Yoon, Kyung Hee;Yoon, Sun;Lee, Mung Hee
    • Journal of the Korean Society of Food Science and Nutrition
    • /
    • v.12 no.1
    • /
    • pp.7-11
    • /
    • 1983
  • The purpose of this study was to prepare low methoxyl pectins (LMPs) by pectinesterase (PE) using waste tangerine peels and to compare the chemical, physical and gelling properties of the prepared pectins with the commercial LMP. The LMPs were prepared by treating albedo with 0.25M $Na_2CO_3$ to activate the PE. PE was then inactivated by heating. The sample was centrifuged and the supernatant was collected. LMP was obtained as precipitate by adding alcohol to the collected supernatant. The amounts of extractible pectins in albedo were 12.71~12.98% on a dry weight basis. Methoxyl contents of LMPs prepared by treating albedo with PE at pH 7.5 for 10min, at pH 8.5 for 10min, 20min and 30min were 5.12%, 4.27%, 3.08%, 1.85% respectively, demonstrating that the methoxyl contents of the preparations decreased as the degree of treatment albedo with PE increased. The acetyl contents of the preparations ranged from 0.09% to 0.12%, the values of which do not interfere with gel formation. The anhydrouronic acid contents of the prepared pectins were in the range of 94.2%~94.8%. The values of viscosity and molecular weights of the prepared LMPs tent to decrease as the degree of PE action on albedo increased. The textural value of the prepared LMP gels determined by Consistometer, Ridgelimeter and Instron denonstrated that the excess treatment of albedo with PE significantly impaired the gelling properties of the preparations.

  • PDF