• Title/Summary/Keyword: filling capacity

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Human Capacity Issues Along the STEM Pipeline

  • Melkers, Julia
    • STI Policy Review
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    • v.1 no.2
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    • pp.1-18
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    • 2010
  • The development and maintenance of human capacity in economies is critical to long term competitiveness, but also for the overall health and environment of regions. Yet, human science and technology-based capacity is multidimensional and has interrelated characteristics which present certain policy challenges. This paper addresses a range of issues specific to a discussion on human capacity in S&T. First, the paper emphasizes the importance of acknowledging the complexity of human capacity issues and how they evolve along the STEM (science, technology, engineering, and mathematics) pipeline. The pipeline is an often used reference to describe the training and development in STEM disciplines, from early childhood education, to more advanced training, and finally to professional collaboration and interaction and serves as a useful organizing framework for the discussion of capacity along the career evolution process. Second, the paper offers an organizing framework for discussion of policy mechanisms that have been developed to address issues and gaps that occur along this STEM pipeline. Specifically, it contrasts the traditional mechanisms of building human capacity in STEM areas with newer "gap filling" and integrated approached to addressed human capacity disparities and priorities. Third, the paper addresses core challenges in human capacity in STEM, including the education and training, participation of women and underrepresented groups, brain drain/brain circulation issues, and the globalization of science. The paper concludes with a discussion of policy implication for the development of human capacity.

Performance Evaluation of Pile-Filling Material Using High Calcium Ash by Field Loading Test (고칼슘 연소재를 이용한 매입말뚝 주면고정액의 현장 재하시험을 통한 성능평가)

  • Seo, Se-Kwan;Kim, You-Seong;Lim, Yang-Hyun;Jo, Dae-Sung
    • Journal of the Korean Geotechnical Society
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    • v.34 no.6
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    • pp.17-24
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    • 2018
  • In this study, static load test and dynamic load test were performed to evaluate pile-filling material (ZA-Soil) of soil-cement injected precast pile method which was developed by using the ash of circulating fluidized boiler as a stimulant for alkali activation reaction of blast furnace slag. As a result of the static load test, the allowable bearing capacity of pile was 1,350 kN, which was the same as the result of using ordinary portland cement. And total settlement was 6.97 mm, and net settlement was 1.48 mm. These are similar to the total settlement, 7.825 mm, and net settlement, 2.005 mm of ordinary portland cement. As a result of the dynamic load test and CAPWAP analysis, the skin friction was 375.0 kN, the end bearing capacity was 3,045.9 kN, and the allowable bearing capacity was 1,368.36 kN. These results are similar to the results of using ordinary portland cement as pile-filling material.

Estimation of Bearing Capacity for Open-ended Pile in Sands Considering Soil Plugging (II) - Applicability of New Design Equation - (사질토지반에서 폐색효과를 고려한 개단말뚝의 지지력 산정 (II) - 새로운 지지력 산정식의 적용성 -)

  • 백규호
    • Journal of the Korean Geotechnical Society
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    • v.18 no.4
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    • pp.199-206
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    • 2002
  • The bearing capacity of open-ended piles is affected by the degree of soil plugging, which is quantified by the incremental filling ratio, IFR. However, most design criteria for open-ended piles do not consider the variation of pile bearing capacity with IFR. In this study, new design equations for calculating the pile base and shaft load capacities, based on IFR value of the pile, were proposed using the results of model pile tests. A full-scale pile load test was also conducted on fully instrumented open-ended pile driven into gravelly sand. The IFR for the pile was continuously measured during pile driving. In order to check the accuracy of predictions made with the proposed equations, the equations were applied to two examples, including the pile load test preformed in this study. Based on the comparisons with the pile load tests results, the proposed equations appear to produce satisfactory predictions.

A Study on the Adsorption Properties of Diisopropyl Methyl Phosphonate on Chromium-Based Metal-Organic Frameworks Using Acetic Acid as a Modulator (아세트산을 조절인자로 제작한 크롬 기반 금속유기골격체의 diisopropyl methyl phosphonate 흡착 특성 연구)

  • Sangjo Jeong
    • Applied Chemistry for Engineering
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    • v.34 no.6
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    • pp.596-602
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    • 2023
  • Chromium-based metal-organic frameworks (MIL-101(Cr)) were synthesized, and their potential use as a filling material for gas masks or protective clothing was assessed through adsorption experiments using diisopropyl methyl phosphate (DIMP) as a simulant for chemical warfare agents. MIL-101(Cr) was prepared using acetic acid (MIL-101(Cr)-A) and sodium hydroxide (MIL-101(Cr)-N) as modulators. The use of acetic acid as a modulator resulted in a larger specific surface area and a higher DIMP adsorption capacity. MIL-101(Cr)-A absorbed approximately 160% of its own weight of moisture when exposed to an environment with a relative humidity of 90% for 10 days, surpassing other adsorbents such as activated carbon. The DIMP adsorption capacity of MIL-101(Cr)-A decreased to about 40% of its initial adsorption capacity after 24 hours of exposure to an environment with a relative humidity of 90%. However, this capacity is still higher compared to that of activated carbon used in commercial gas masks, suggesting a high potential for future use as a filling material for gas masks or protective clothing.

Reinforcement for Bearing Capacity of PRD Steel Pile at Mudstone Area (이암지역에 근입된 PRD강관말뚝의 지지력 보강)

  • Kong, Jin-Young;Kang, Hee-Jin;Chun, Byung-Sik
    • Proceedings of the KSR Conference
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    • 2007.05a
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    • pp.1760-1769
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    • 2007
  • The cut slope sliding which has been frequently encountered in Pohang area has been reported due to the rapid reduction of shear strength in mudstone after being exposed to the air. Mudstone has characteristics that it has high enough strength and stiffness in a dry condition, but the strength and stiffness decrease in a wet condition with groundwater infiltration. The case study in this paper shows that mudstone which had enough strength in a boring stage has lost the strength after installing PRD steel pipe pile inducing an insufficient bearing capacity, which has been ascertained by the static load test. Test construction has been performed to investigate the most favorable method for increasing a pile bearing capacity in mudstone with various methods such as MSG (Micro Silica Grouting) around the tip and side of a pile, the perimeter grouting combined with Micro pile reinforcement, and concrete filling after tip reinforcing grouting. From the test construction, MSG has been turned out to be the most favorable method for increasing a pile bearing capacity in mudstone, which has been confirmed by the static load test.

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An Experimental Study on Shear Resisting Effect of Reinforced Concrete Beams Filling-up Carbon Fiber Rod Plastic (CFRP로 매립 보강된 RC보의 전단 보강 효과에 관한 실험적 연구)

  • Kim, Young-Sik;Lee, Hyung-Seok;Park, Sung-Moo
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.9 no.4
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    • pp.187-194
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    • 2005
  • The purpose of this study is to investigate experimentally the shear resisting behavior of the reinforced concrete beams strengthened with reinforcement materials. Seven specimens were manufactured and tested under static monotonic loading. The main variables in the test were the method and direction of reinforcement. This research is about the experiment of shear capacity of reinforced concrete beams strengthened with CFRP-rod, in the filling-up method. The test result indicated that the method of CFRP increase significantly the ultimate shear strength of a reinforced concrete beam.

Effect of Yellowing Times During Yellowing Stage on Physico-chemical Properties of Immature Tobacco Leaves in Bulk Curing (Bulk건조시 미숙엽의 황변시간 조절이 잎담배 이화학성에 미치는 영향)

  • 이철환;진정의;한철수;이승철
    • Journal of the Korean Society of Tobacco Science
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    • v.21 no.1
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    • pp.10-16
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    • 1999
  • Leaves harvested were separated with visual characters into 2 classes such as immature and mature leaves. In the curing process, the prolonged yellowing treatment during yellowing stage was automatically controlled at the different stalk position, and condition of curing process after this period was all the same with conventional ones. In case of prolonged yellowing in immature leaves, increase of price per kg reached to 8 % compared with those of conventional ones. In physical properties, filling capacity and shatter index was decreased with the degree of maturity, and it was equal level in filling capacity of immature leaves between curing method, while shatter index was decreased in prolonged yellowing treatment than that of conventional ones. There was no difference in chemical components between immature leaves of prolonged yellowing and conventional ones. As to the prolonged yellowing of immature leaves, there was decreased in citric and malic acid contents of the nonvolatile organic acids, and it was equal level in all higher fatty acids content of leaves cured by prolonged yellowing treatment compared with in that of conventional curing method. The contents of key compounds such as solanone, damascenone, damascone in the essential oil were lower in prolonged yellowing of immature leaves than those of mature leaves cured by conventional ones.

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Bulk 건조엽의 편평엽 발생양상과 이화학적 특성

  • 이철환;진점의;한철수
    • Journal of the Korean Society of Tobacco Science
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    • v.20 no.2
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    • pp.139-143
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    • 1998
  • The occurrence and physico-chemical properties of flat leaves found in 1997 curing trial related to the prevention of occurrence of flat leaves at bulk curing of flue-cured tobacco were investigated and compared with those of normal leaves. Cured leaves of NC82 were separated into 4 classes of none, slight, fair and severe symptoms of flat leaf by the percentage of flattened parts to whole leaf area. The flat leaves were mostly found among the leaves of lower stalk position, and it was estimated that growth rate of lower leaves also influenced on the occurrence of flat leaves. In chromatic aberration of cured leaf, flat leaves showed remarkably lower b and L values than in those of normals but there was no difference in a value. On the other hand, in chemical analyses of flat leaf samples, nicotine, total sugar, ether extract and total nitrogen contents were decreased with the degree of flat symptoms. In physical properties, filling capacity of cured leaves was decreased with the degree of flat symptoms comparing with those of normal leaves, while shatter index was showed a reverse tendency, and then within the same leaf, flat parts were decreased in total sugar, ether extract and filling capacity compared with those of normal ones, but remarkably increased in shatter index, and there was no difference in nicotine and total nitrogen contents.

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Aggregate Criterion for Paved Track Considering Recycling of Railway Ballast (도상자갈 재활용을 고려한 포장궤도용 골재 기준)

  • Lee, Il-Wha
    • Journal of the Korean Society for Railway
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    • v.12 no.4
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    • pp.481-487
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    • 2009
  • On the paved track, the railway ballast is used as aggregate for the filling layer using the pre-packed concrete method. The condition of ballast as the paved track aggregate ensure that the compressive strength, particle distribution size for the pouring and surface clearance to increase the adhesive strength with mortar. It is profitable to recycle the existing railway ballast as a economical supply. In order to increase recycling characteristic, it is necessary to apply the similar criterion which does not exceed the conventional railway ballast criterion. Consequently, this paper was to investigate physical characteristics of existing ballast, particle size distribution, compressive and flexural strength, bearing capacity and filling capacity to prepare the aggregate's recycling. As a result, optimized aggregate criterion is suggested.

Analysis of Back-to-back Refueling for Heavy Duty Hydrogen Fuel Cell Vehicles Using Hydrogen Refueling Stations Based on Cascade System (캐스케이드 시스템 기반 수소 충전소를 이용한 대형 수소 연료 전지 차량 연속 충전 분석)

  • GYU SEOK SHIM;BYUNG HEUNG PARK
    • Transactions of the Korean hydrogen and new energy society
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    • v.35 no.3
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    • pp.300-309
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    • 2024
  • Hydrogen utilization in the transportation sector, which relies on fossil fuels, can significantly reduce greenhouse gas by using to hydrogen fuel cell vehicles, and its adoption depends performance of hydrogen refueling station. The present study developed a model to simulate the back-to-back filling process of heavy duty hydrogen fuel cell vehicles at hydrogen refueling stations using a cascade method. And its quantitatively evaluated hydrogen refueling station performance by simulating various mass flow rates and storage tank capacity combinations, analyzing vehicle state of charge (SOC) of vehicles. In the cascade refueling system, the capacity of the high-pressure storage tank was found to have the greatest impact on the reduction of filling time and improvement of efficiency.