• Title/Summary/Keyword: High-capacity

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Antioxidant Characteristics and Phytoremediation Potential of 27 Taxa of Roadside Trees at Industrial Complex Area (공단지역에서 생육하는 가로수 27종의 항산화특성과 잠재적 환경정화능력)

  • Han Sim-Hee;Lee Jae-Cheon;Oh Chang-Young;Kim Pan-Gi
    • Korean Journal of Agricultural and Forest Meteorology
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    • v.8 no.3
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    • pp.159-168
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    • 2006
  • In order to screen for the best species for mitigating air pollutants by plants at an industrial complex area, we investigated antioxidant capacity, lipid peroxidation and nitrogen content in the leaves of 27 taxa of woody plants that are mostly utilized as roadside trees. Among 27 taxa, the highest value of antioxidant capacity was given by Cedrus deodara (91.4%) and the lowest one was by Firmiana simplex (56.9%). At lipid peroxidation level, little malondialdehyde (MDA) was observed in Lagerstroemia indica and Ginkgo biloba, but Platanus occidentalis, Castanoposis cuspidata var, sieboldii, Machilus thunbergii and Juniperus chinensis showed high MDA content. Antioxidant capacity of the deciduous woody plants was not significantly different in comparison with that of the evergreen ones. But MDA content of the deciduous woody plants was lower than that of the evergreen ones. The 27 taxa of woody plants appeared to be classified into four types: those of high antioxidant capacity and low lipid peroxidation, those of high antioxidant capacity and high lipid peroxidation, those of low antioxidant capacity and low lipid peroxidation, and those of low antioxidant capacity and high lipid peroxidation. The taxa included in these types are 7 (first type), 6 (second one), 8 (third one) and 6 (fourth one) taxa. first or second type species which have a high antioxidant capacity represented low nitrogen content in their leaves. However, third or forth type species which have low antioxidant capacity showed high nitrogen content in their leaves. Metasequoia glyptostroboides, Platycarya strobilacra and P. occidentalis which belong to the first or second type had extraordinarily high antioxidant capacity and high nitrogen content. Thus, three species are considered to be good phytoremediators for an industrial complex area.

Moment redistribution of continuous composite I-girder with high strength steel

  • Joo, Hyun Sung;Moon, Jiho;Sung, Ik-Hyun;Lee, Hak-Eun
    • Steel and Composite Structures
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    • v.18 no.4
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    • pp.873-887
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    • 2015
  • The continuous composite I-girder should have a sufficient rotation capacity (or ductility) to redistribute the negative bending moment into an adjacent positive bending moment region. However, it is generally known that the ductility of the high strength steel is smaller than that of conventional steel, and application of high strength steel can cause ductility problems in a negative moment region of the I-girder. In this study, moment redistribution of the continuous composite I-girder with high strength steel was studied, where high strength steel with yield stress of 690 MPa was considered (the ultimate stress of the steel was 800 MPa). The available and required rotation capacity of the continuous composite I-girder with high strength steel was firstly derived based on the stress-strain curve of high strength steel and plastic analysis, respectively. A large scale test and a series of non-linear finite element analysis for the continuous composite I-girder with high strength steel were then conducted to examine the effectiveness of proposed models and to investigate the effect of high strength steel on the inelastic behavior of the negative bending moment region of the continuous composite I-girder with high strength steel. Finally, it can be found that the proposed equations provided good estimation of the requited and available rotation capacity of the continuous composite I-girder with high strength steel.

A Study on Shear Capacity of High Strength Lightweight Reinforced Concrete T-Beams (고강도 경량콘크리트를 사용한 철근콘크리트 T 형보의 전단성능)

  • 김진수;김원호;박성무
    • Proceedings of the Korea Concrete Institute Conference
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    • 1993.10a
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    • pp.220-225
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    • 1993
  • This paper is an experimental study on shear capacity of the high strength lightweight reinforced concrete beams with shear-depth ratio between 1.5 and 2.5. Thirteen T & rectangular beams were tested to determine their diagonal cracking and ultimate shear capacity. The major variables are shear span-depth ratio (a/d=1.5, 2.0, 2.5), concrete compressive strength(f'c=210, 24., 270㎏/㎠) and tensile steel ratio( =0.6, 1.2%). Based on results obtained from experiment of high strength lightweight reinforced concrete Beam & normal concrete, the following conclusions were drawn. (1) The shear capacity of high-strength lightweight concrete is less 15% than that of normal concrete under same condition. (2) As the results of Comparing this experimental datas with other various formulas. It is regarded that ACI 318-89 shear strength formula related tensile strength is proper to design formula of shear strength of high-strength lightweight reinforced concrete using lightweight concrete.

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A Numerical Analysis Study for Estimation of Ultimate Bearing Capacity and An Analysis of the High Capacity Bi-directional Pile Load Tests of the Large-diameter Drilled Shafts (대구경 현장타설말뚝의 대용량 양방향 말뚝재하시험 분석 및 극한지지력 추정을 위한 수치해석 연구)

  • Nam, Moonsuk;Kim, Sangil;Hong, Seokwoo;Hwang, Seongchun;Choi, Yongkyu
    • Journal of the Korean GEO-environmental Society
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    • v.12 no.10
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    • pp.63-72
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    • 2011
  • The high capacity bi-directional pile load test is an optimum pile load test method for high-rised buildings. Especially, a high pressure and double-acting bi-directional pile load testing, a special type of the high capacity bi-directional pile load test, is the most practical way to overcome limitations of loading capacities and constraints of field conditions, which was judged to be a very useful test method for requiring high loading capacities. Total of 2 high capacity bi-directional pile load tests(P-1 and P-2) were conducted in high-rised building sites in Korea. Based on the field load test results, the sufficiency ratio of loading capacities to design loads for P-1 and P-2 were 3.3 and 2.1, respectively. For P-2, the load test could not verify the design load if 1-directional loads applied slightly smaller than the actual applied load. Also, high capacity bi-directional pile load tests were difficult to determine an ultimate state of ground or piles, although the loads were applied until their maximum loads. Hence, finite element analyses were conducted to determine their ultimate states by calibrating and extrapolate with test results.

Seismic tests of RC shear walls confined with high-strength rectangular spiral reinforcement

  • Zhao, Huajing;Li, Qingning;Song, Can;Jiang, Haotian;Zhao, Jun
    • Steel and Composite Structures
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    • v.24 no.1
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    • pp.1-13
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    • 2017
  • In order to improve the deformation capacity of the high-strength concrete shear wall, five high-strength concrete shear wall specimens confined with high-strength rectangular spiral reinforcement (HRSR) possessing different parameters, were designed in this paper. One specimen was only adopted high-strength rectangular spiral hoops in embedded columns, the rest of the four specimens were used high-strength rectangular spiral hoops in embedded columns, and high-strength spiral horizontal distribution reinforcement were used in the wall body. Pseudo-static test were carried out on high-strength concrete shear wall specimens confined with HRSR, to study the influence of the factors of longitudinal reinforcement ratio, hoop reinforcement form and the spiral stirrups outer the wall on the failure modes, failure mechanism, ductility, hysteresis characteristics, stiffness degradation and energy dissipation capacity of the shear wall. Results showed that using HRSR as hoops and transverse reinforcements could restrain concrete, slow load carrying capacity degeneration, improve the load carrying capacity and ductility of shear walls; under the vertical force, seismic performance of the RC shear wall with high axial compression ratio can be significantly improved through plastic hinge area or the whole body of the shear wall equipped with outer HRSR.

The Study of Basic Direction and Successful Fixation Way for Enhancing Educational Capacity of General High School in Gyeongsangbuk-do (경상북도 일반고의 교육역량 제고를 위한 기본방향과 성공적인 정착방안 탐색)

  • Chung, Il-Hwan
    • Korean Journal of Comparative Education
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    • v.24 no.3
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    • pp.1-23
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    • 2014
  • The purpose of this study is to analyze some problems of general high school and provide some promotion ways of general high school in Gyeongsangbuk-do in long and short term perspective, considering necessity for consolidating educational capacity of general high school which is in disadvantage due to high school diversity and special high school promotion policy. For this, first, the study explores educational policy basis of Park Geun-hye's government, educational policy direction of Gyeongsangbuk-do, educational situation of general high school in Gyeongbuk area, and main contents of educational capacity consolidation way of general high school. Main tasks of Gyeongsangbuk-do general high school educational capacity reconsideration based on the educational capacity consolidation way of Ministry of Education are (1) enlargement of autonomy for formation and operation of focused curriculum by guidance, (2) enlargement of guidance and vocational education for general high school student, (3) consolidation of support program for student at risk, and (4) consolidation of support for general high school High-up program. For these main tasks are fixed and operated in school successfully, the fixation of school responsible management system based on geological environment and trait of each general high school, the application of whole quality control in school management, and the formation of cooperative school organizational culture should be constructed. And specific practice tasks and strategies for Gyeongsangbuk-do general high school educational capacity reconsideration (the cultivation of grobal democratic citizen, human being image in 2009 revised curriculum, and 'talented people with new thinking and genuine mind' of Gyeongsangbuk-do) are provided.

The Study of Load Test Method for In-Site Casting Pile In High Rise Building. (초고층에서의 현장타설말뚝 재하시험방법 고찰)

  • Kim, Dae-Hak;Hong, Young-Kil;Han, Sung-Moo;Gu, Ung-Hwoe;Park, Chan-Duck
    • Proceedings of the Korean Geotechical Society Conference
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    • 2008.03a
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    • pp.385-392
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    • 2008
  • Modern city have had a lot of high-rise building in high standards and multi-level performance. Using of city space reach better stages by using integration. These skyscraper have increased working load on ground. that building is efficiently designed for that soil capacity is well applied. With material side, big size pile, high strength concrete and high strength steel is used for that getting enough lobby space and resisting load increased of high-rise building. limit load test and load transmitted test can make soil capacity optimized. By the way, method of measuring pile capacity is more advanced and bigger. pile type applied by high rise building have underground excavation space, also reflect regional soil property and have some fact reviewed. A lot of high rise building recently is built as land mark in Seoul, Busan and Incheon. about method of measuring capacity of foundation pile, example of construction field is compared and reviewed.

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High-strength RC columns subjected to high-axial and increasing cyclic lateral loads

  • Bhayusukma, Muhammad Y.;Tsai, Keh-Chyuan
    • Earthquakes and Structures
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    • v.7 no.5
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    • pp.779-796
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    • 2014
  • This experimental investigation was conducted to examine the behavior and response of high-strength material (HSM) reinforced concrete (RC) columns under combined high-axial and cyclic-increasing lateral loads. All the columns use high-strength concrete ($f_c{^{\prime}}$=100MPa) and high-yield strength steel ($f_y$=685MPa and $f_y$=785MPa) for both longitudinal and transverse reinforcements. A total of four full-scale HSM columns with amount of transverse reinforcement equal to 100% more than that required by earthquake resistant design provisions of ACI-318 were tested. The key differences among those four columns are the spacing and configuration of transverse reinforcements. Two different constant axial loads, i.e. 60% and 30% of column axial load capacity, were combined with cyclically-increasing lateral loads to impose reversed curvatures in the columns. Test results show that columns under 30% of axial load capacity behaved much more ductile and had higher lateral deformational capacity compared to columns under the 60% of axial load capacity. The columns using closer transverse reinforcement spacing have slightly higher ductility than columns with larger spacing.

pH Variation In Soils Considering Buffer Capacity during Electrokinetic Extraction (Electrokinetic정화시 토질의 완충능을 고려한 시료내의 pH변화)

  • 오승록;한상재;김수삼;조성호
    • Proceedings of the Korean Geotechical Society Conference
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    • 2001.03a
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    • pp.585-590
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    • 2001
  • Physicochemical phenomena in soils are dependent upon pH when using electrokinetic extraction for the contaminants removal especially for heavy metals. pH variation in soils is affected on H$\^$+/ and OH ̄ ions produced by electrolysis reaction and buffer capacity of soil. High amount of heavy metals are retained in the soils if the soil buffer capacity remains high enough to resist a change in pH. Therefore, accurate pH estimation of soil is important in the application of electrokinetic mechanism for decontamination and understanding of subsurface physicochemical characteristics is also required as well as considering buffer capacity for the enhanced methods application. For these, buffer capacity and pH distribution were measured for the four soils, and also compared with modeling results. The results of buffer modeling were good agreement with experimental data. It is showed that four soils were effected by buffer capacity

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Evaluations of Si based ternary anode materials by using RF/DC magnetron sputtering for lithium ion batteries

  • Hwang, Chang-Muk;Park, Jong-Wan
    • Proceedings of the Korean Vacuum Society Conference
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    • 2010.08a
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    • pp.302-303
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    • 2010
  • Generally, the high energy lithium ion batteries depend intimately on the high capacity of electrode materials. For anode materials, the capacity of commercial graphite is unlike to increase much further due to its lower theoretical capacity of 372 mAhg-1. To improve upon graphite-based negative electrode materials for Li-ion rechargeable batteries, alternative anode materials with higher capacity are needed. Therefore, some metal anodes with high theoretic capacity, such as Si, Sn, Ge, Al, and Sb have been studied extensively. This work focuses on ternary Si-M1-M2 composite system, where M1 is Ge that alloys with Li, which has good cyclability and high specific capacity and M2 is Mo that does not alloy with Li. The Si shows the highest gravimetric capacity (up to 4000mAhg-1 for Li21Si5). Although Si is the most promising of the next generation anodes, it undergoes a large volume change during lithium insertion and extraction. It results in pulverization of the Si and loss of electrical contact between the Si and the current collector during the lithiation and delithiation. Thus, its capacity fades rapidly during cycling. Si thin film is more resistant to fracture than bulk Si because the film is firmly attached to the substrate. Thus, Si film could achieve good cycleability as well as high capacity. To improve the cycle performance of Si, Suzuki et al. prepared two components active (Si)-active(Sn, like Ge) elements film by vacuum deposition, where Sn particles dispersed homogeneously in the Si matrix. This film showed excellent rate capability than pure Si thin film. In this work, second element, Ge shows also high capacity (about 2500mAhg-1 for Li21Ge5) and has good cyclability although it undergoes a large volume change likewise Si. But only Ge does not use the anode due to its costs. Therefore, the electrode should be consisted of moderately Ge contents. Third element, Mo is an element that does not alloys with Li such as Co, Cr, Fe, Mn, Ni, V, Zr. In our previous research work, we have fabricated Si-Mo (active-inactive elements) composite negative electrodes by using RF/DC magnetron sputtering method. The electrodes showed excellent cycle characteristics. The Mo-silicide (inert matrix) dispersed homogeneously in the Si matrix and prevents the active material from aggregating. However, the thicker film than $3\;{\mu}m$ with high Mo contents showed poor cycling performance, which was attributed to the internal stress related to thickness. In order to deal with the large volume expansion of Si anode, great efforts were paid on material design. One of the effective ways is to find suitably three-elements (Si-Ge-Mo) contents. In this study, the Si based composites of 45~65 Si at.% and 23~43 Ge at.%, and 12~32 Mo at.% are evaluated the electrochemical characteristics and cycle performances as an anode. Results from six different compositions of Si-Ge-Mo are presented compared to only the Si and Ge negative electrodes.

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