• Title/Summary/Keyword: Fines

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Effects of Low-quality Aggregates in the Same Workability Conditions on the Engineering Properties of Concrete (저품질 골재가 동일 작업성 조건에서 콘크리트 공학적 특성에 미치는 영향)

  • Min, Kyeong-Chul;Han, Cheon-Goo
    • Journal of the Korean Recycled Construction Resources Institute
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    • v.4 no.3
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    • pp.299-306
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    • 2016
  • In this research, influence of low quality aggregate on engineering properties of concrete was evaluated experimentally. From the experiment, the fresh properties of slump and air content were controlled with unit water and AE dosage and all mixture were designed to have similar fresh properties of slump and air content with various quality of aggregate. Under this conditions, comparing with the mixture with high quality aggregate, the mixture with low quality aggregate showed the unit water and AE dosage were increased about 18 and 98%, respectively, because of poor grading and quantity of fines. For compressive strength, the low quality aggregate, specifically, exploded debris, clay sand, and sea sand contributed on decreasing compressive strength about 20~35%. Additionally, the concrete mixture including low quality fine and coarse aggregate showed adverse quality in not only compressive strength but also durability of freeze-thawing resistance, drying shrinkage, carbonation, and chloride ingression. Therefore, it is considered that for low quality aggregate, extra treatment processes such as washing or controlling gradation, and regulation to limit the use of low quality aggregate are needed.

Characteristics of Carbidization for Iron Ore Fines with a Wide Size Range (입도분포가 넓은 분철광석의 탄화특성)

  • Hwang Ho-Sun;Chung Uoo-Chang;Chung Won-Sub;Chung Won-Bae
    • Resources Recycling
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    • v.12 no.5
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    • pp.42-49
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    • 2003
  • Characteristics of reduction and carbidization for hematite ore with a wide size range have been investigated at high temperature(590∼64$0^{\circ}C$) under $H_2$ and $H_2$-CO gas mixtures. The apparent activation energy for reduction of hematite ore with H2 gas was found to be 20 kJ/mol. The weight loss by reduction was about 28% md the weight gain by carbidization was about 5%. The measured values of weight change were compared with those calculated from equation (3) & (5) and fairly good agreement was obtained. The rate of carbidization was increased with an decrease in temperature, particle diameter and gas ratio($H_2$/ CO). The free carbon was increased with decrease in gas ratio($H_2$/ CO). The rate of carbidization was increased with mixing of $H_2$ gas but this effect was not proportional to fraction of $H_2$ gas. It was also found that the rate of carbidization was the maximum in the $H_2$ gas fraction of 0.5. It is considered that $H_2$ plays a part as a catalyst for formation of iron carbide($Fe_3$C).

Natural Environment of Silk Road (실크로드의 자연환경)

  • Son, Myoung-Won
    • Journal of the Korean association of regional geographers
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    • v.11 no.1
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    • pp.29-39
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    • 2005
  • Silk Road is the term involving all traffic roads connecting the East to the West, and ancient Korean culture has became globalized through Silk Road. In this paper, natural environment of Silk Road is considered as fundamental data in order to understand the Western culture introduced through Silk Road. Silk Road region is classified into Loess Plateau district; arid basin district; and high mountains district; Hesi Corridor(河西回廊) is the transition zone that the southeastern part of $W{\breve{u}}w{\bar{e}}i$(武威) is Loess Plateau district; other northwestern part is arid basin district Loess Plateau district, composed of homogeneous fines, has experienced dramatic soil loss by bringing under cultivation. At recent times, reforestation and construction of check-dam have been in operation to cope with this problems, Arid basin district; although at midlatitude, is desert climate because it is far from the ocean and is surrounded by high mountains. Oasis of Hesi Corridor is continuous linearly, but that of arid basin district is sporadic. In $H{\bar{a}}mi$ and $T{\breve{u}}l{\breve{u}}f{\bar{a}}n$(吐魯番) fruit-growing using karez flourishes, And glacier of $Ti{\bar{a}}nshian$(天山) Mts. and $Q{\bar{i}}lian$(祁連) Mts. is very important to arid basin district because of supplying water resource. In the tundra zone surrounding alpine glacier, are distributed widely solifluction lobes and earth hummocks.

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A critical review on informed consent in the revised Medical Law (개정 의료법상 설명의무에 관한 비판적 고찰)

  • Hyun, Dooyoun
    • The Korean Society of Law and Medicine
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    • v.18 no.1
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    • pp.3-35
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    • 2017
  • The Supreme Court of Korea first admitted compensation for damages caused by breach of informed consent in 1979. From then on, specific details of informed consent are shaping up and developing through court precedents. The duty of informed consent of doctor is based on article 10 of the Constitution and medical contract, and is expressly prescribed Article 12 of Framework Act on Health and Medical Services and other acts and regulations. By the way, the regulations about duty of informed consent of doctor have been established in Medical Law revised on December 20, 2016, and the revised Medical Law will be implemented on June 21, 2017. According to the revised Medical Law, medical practices subject to description and consent are operation, blood transfusion and general anesthesia that threaten to cause serious harm to human life or to the body. When performing these medical activities, the written consent must be explained and agreed upon in advance. If a doctor violates the law, he will incur fines of less than 3 million won. Comparing and viewing the revised Medical Law and existing legal principles about the duty of informed consent, we can confirm that there is a substantial difference between the two parties. Accordingly, despite the implementation of the revised medical law, the existing legal principles are unlikely to be affected. However, from the perspective of legal uniformity and stability, it is undesirable that legal judgments on the same issues differ from each other. The revised Medical Law about informed consent needs to be reformed according to existing legal principles. And, as in the case of Germany, it is desirable to include the matters concerning informed consent in the civil code.

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A Study on Magnitude Scaling Factors and Screening Limits of Liquefaction Potential Assessment in Moderate Earthquake Regions (중진지역에 적합한 액상화 평가 생략기준 및 지진규모 보정계수에 관한 연구)

  • Park Keun-Bo;Park Young-Geun;Choi Jae-Soon;Kim Soo-Il
    • Journal of the Korean Geotechnical Society
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    • v.20 no.7
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    • pp.127-140
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    • 2004
  • Conventional methods for the assessment of liquefaction potential were primarily for areas of severe earthquake zones (M=7.5) such as North America and Japan. Detailed earthquake related researches in Korea started in 1997, including development of the seismic design standards for port and harbour structures, which was later completed in 1999. Because most contents in the guidelines were quoted through literature reviews from North America and Japan, which are located in strong earthquake region, those are not proper in Korea, a moderate earthquake region. This requires further improvement of the present guidelines. Considering earthquake hazard data in Korea, use of laboratory tests based on irregular earthquake motion appears to be effective to reflect the dynamic characteristics of soil more realistically than those using simplified regular loading. In this study, cyclic triaxial tests using irregular earthquake motions are performed with different earthquake magnitudes, relative densities, and fines contents. Assessment of liquefaction potential in moderate earthquake regions is discussed based on various laboratory test results. Effects of these components on dynamic behavior of soils are discussed as well. From the test results, screening limits and magnitude scaling factors to determine the soil liquefaction resistance strength in seismic design were re-investigated and proposed using normalized maximum stress ratios under real irregular earthquake motions.

Analysis of Traffic Noise for Single and Double Layered Porous Pavement with SPB Method -National Route 1, Sejong-Si Section- (SPB측정법에 의한 복층 및 단층 다공성포장의 소음분석 -국도 1호선 세종시 구간-)

  • Yoo, In-Kyoon;Lee, Su-Hyung;Han, Dae-Seok
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.21 no.9
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    • pp.92-102
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    • 2020
  • Porous pavement (PP) has attracted attention as a new alternative measure against road traffic noise. PP refers to pavement that reduces the fines in the asphalt mixture to form voids. These voids can reduce traffic accidents and friction noise. For active application, verification of the noise reduction effect is required. In this study, the noise reduction of single-layer PP(SLPP) and double layer PP(DLPP) was analyzed. First, the Sejong section was selected, and traffic noise was measured using the SPB method on the roadside. The traffic volume, speed, and mixing ratio of large vehicles were measured. As a result, the DLPP was evaluated to be 7.95 dB(A) smaller on average and 7.57dB(A) smaller at the 95% reliability level than the SLPP. The traffic volume was more influential than the speed and the mixing rate of large vehicles. As the traffic volume increased, the noise increased, but the difference in noise between the two pavements decreased gradually. The results showed that the most effective way to reduce road traffic noise is to change the road pavement rather than reduce traffic speed, restrict traffic for heavy vehicles, or reduce traffic volume.

Analysis of Effects on Adoption of a Safety e-Reporting System (안전신고 제도(안전신문고) 도입에 따른 효과 분석)

  • Lee, Jun;Cho, Sangmyeong;Park, Eunmi;Lee, Sanghwa
    • Journal of Korean Society of Disaster and Security
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    • v.12 no.4
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    • pp.27-41
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    • 2019
  • To analyze the effectiveness of the safety e-reporting system, the present study carried out analysis of safety e-reporting data reported between September 2014 and July 2019, and selected items for measuring the effectiveness of safety e-reporting. Using these items, the effects of adopting the reporting system for the four major parking violations was analyzed, alongside an analysis of effects in terms of traffic accidents using the unit model. When we count the securement of the tax revenue through measures such as charging fines as the beneficial factor per case, the estimation of the benefit is around 62,000 KRW per case. Summing the two factors up, the total value of citizen's reports pertaining to the big four parking violations is about 275,000 KRW per case. Most of the reports made through the Safety e-Report system are about traffic and facilities. When we calculate the total annual benefit with the representative reporting value defined with traffic and facilities, the system received a total of 1,164,439 cases from 2014 to 2019, while citizens reported 52,721 cases for the big four parking violations from April to July 2019. As the value of a safety report is around the net benefit for last five years is around 27,340,000,000 KRW.

The Frost Heaving Characteristics of Subgrade Soils Using Laboratory Freezing System (실내동결시스템을 이용한 노상토의 동상 특성)

  • Shin, Eun-Chul;Ryu, Byung-Hyun;Park, Jeong-Jun
    • International Journal of Highway Engineering
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    • v.12 no.2
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    • pp.71-79
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    • 2010
  • The influence of fines of the frost susceptibility of subgrade soils were established by laboratory freezing system test simulating closely the thermal conditions in the field. During the winter season, the climate is heavily influenced by the cold and dry continental high pressure. Because of siberian air mass, the temperature of January is $-6{\sim}-7^{\circ}C$ on average. This chilly weather generate the frost heaving by freezing the moisture of soil and damage potential of the road structure. In the freezing soil, the ice lenses increase the freeze portion of soil by absorbing the ground water with capillary action. However, the capillary characteristics differ from the sort of soil on the state of freezing condition. In the current design codes for anti-freezing layer, the thickness of anti freezing layer is calculated by freezing depth against the temperature condition. Therefore, they have a tendency of over-design and uniform thickness without the considerations of thermal stability, bearing capacity and frost susceptibility of materials. So, it is essential for studying the appropriateness and bearing capacity besides the seasonal and mechanical properties of pavement materials to take a appropriate and reasonable design of the road structure. In this Paper, the evaluation of frost susceptibility was conducted by means of the mechanical property test and laboratory freezing system apparatus. The temperature, heaving amount, heaving pressure and unfrozen water contents of soil samples, the subgrade soils of highway construction site, were measured to determine the frost susceptibility.

A Study on Rational Improvement of the Gift Regulation in the Telecommunications Market (통신시장의 경품규제에 대한 합리적 개선방안 연구)

  • Kim, Yong-Beom;Kwak, Jeong Ho
    • Journal of Internet Computing and Services
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    • v.18 no.6
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    • pp.137-144
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    • 2017
  • A variety of customized marketing strategies are being implemented in the telecommunications market, including the offering of gifts to consumers, as competition in the market is being restructured with the focus on bundled products. However, the Korea Communications Commission (KCC) has recently imposed fines for user discrimination on telecommunication carriers whose marketing strategies have included the award of excessive prizes. In that regard, various issues related to the suitability and appropriate limit of the current gift regulation in the telecommunications market have been raised. Since the Fair Trade Commission, which had a similar scheme to that of the KCC, abolished the regulation on gifts in July 2016, disputes have arisen as to whether the current regulation on gifts is practically effective from the perspective of consumer benefit. In other words, discussions on the rationality of the theoretical and empirical grounds for the regulation on gifts only in the telecommunication market but not in other commodities markets have begun. As such, this study aims to empirically analyze the suitability of the current regulation on gifts in the domestic telecommunications market under the new competitive environment centered on bundled products, and to seek the rational improvement of, and infer the implications for, the regulation on gifts in the telecommunications market based on the results of the analysis.

Monetary Penalty System and Privacy (벌금형 제도의 현대적 가치와 개인정보문제)

  • Kim, Woon-Gon
    • Journal of the Korea Society of Computer and Information
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    • v.20 no.6
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    • pp.107-115
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    • 2015
  • A fine is defined to the criminal penalty which is slighter than imprisonment on a system of criminal penalty, but put practically a seat to imprisonment and similar strong discipline contrivance to commission agent in capitalism societies be doing. Also, did heavy commission, but the corporation time, a fine to consider the respect which cannot impose other criminal penalty, and cannot but impose fine penalty only to this corporation carries out art as important criminal penalty than the commission which a person does. But fine drawing of our country cannot carry out art scaring to criminal penalty to rich body as aggregate fine drawing, and a lot of, but do abatement duration of a fine so as same, and be most in spite of adjudication criminal sentence occupying at criminal case adjudication, and difference cannot do to an amount of a fine that is carrying well out the art. Therefore, and have to change to the daily fine systemdm which gained because of total fine system in order to carry out value as modern criminal penalty, and a few fines shall exchange to penalty payment system according to complement department canon of Penal Code, and social accusation protects individual information of low commission agent if so, can normally do art accomplishment of criminal penalty. The system that the maximum can guarantee right of defence of accused has to have to be introduced in procedural a few aspect to pronounce this and a fine. Specially, let explain necessary fact to be related to, and informal procedures understand, and introduction of drawing to be able to get from accord of accused is necessary for accused before charging to informal decree in order cannot be guaranteed right of defence this of accused while consisting in writing of whether accusation and adjudication are procedural at informal procedures, and to supplement respect.